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Sample records for irradiated liquid water

  1. Optical Fluorescence Detected from X-ray Irradiated Liquid Water.

    PubMed

    Hans, Andreas; Ozga, Christian; Seidel, Robert; Schmidt, Philipp; Ueltzhöffer, Timo; Holzapfel, Xaver; Wenzel, Philip; Reiß, Philipp; Pohl, Marvin N; Unger, Isaak; Aziz, Emad F; Ehresmann, Arno; Slavíček, Petr; Winter, Bernd; Knie, André

    2017-03-16

    Despite its importance, the structure and dynamics of liquid water are still poorly understood in many apsects. Here, we report on the observation of optical fluorescence upon soft X-ray irradiation of liquid water. Detection of spectrally resolved fluorescence was achieved by a combination of the liquid microjet technique and fluorescence spectroscopy. We observe a genuine liquid-phase fluorescence manifested by a broad emission band in the 170-340 nm (4-7 eV) photon wavelength range. In addition, another narrower emission near 300 nm can be assigned to the fluorescence of OH (A state) in the gas phase, the emitting species being formed by Auger electrons escaping from liquid water. We argue that the newly observed broad-band emission of liquid water is relevant in search of extraterrestrial life, and we also envision the observed electron-ejection mechanism to find application for exploring solutes at liquid-vapor interfaces.

  2. Electronic Excitation Dynamics in Liquid Water under Proton Irradiation

    PubMed Central

    Reeves, Kyle G.; Kanai, Yosuke

    2017-01-01

    Molecular behaviour of liquid water under proton irradiation is of great importance to a number of technological and medical applications. The highly energetic proton generates a time-varying field that is highly localized and heterogeneous at the molecular scale, and massive electronic excitations are produced as a result of the field-matter interaction. Using first-principles quantum dynamics simulations, we reveal details of how electrons are dynamically excited through non-equilibrium energy transfer from highly energetic protons in liquid water on the atto/femto-second time scale. Water molecules along the path of the energetic proton undergo ionization at individual molecular level, and the excitation primarily derives from lone pair electrons on the oxygen atom of water molecules. A reduced charge state on the energetic proton in the condensed phase of water results in the strongly suppressed electronic response when compared to water molecules in the gas phase. These molecular-level findings provide important insights into understanding the water radiolysis process under proton irradiation. PMID:28084420

  3. Electronic Excitation Dynamics in Liquid Water under Proton Irradiation

    NASA Astrophysics Data System (ADS)

    Reeves, Kyle G.; Kanai, Yosuke

    2017-01-01

    Molecular behaviour of liquid water under proton irradiation is of great importance to a number of technological and medical applications. The highly energetic proton generates a time-varying field that is highly localized and heterogeneous at the molecular scale, and massive electronic excitations are produced as a result of the field-matter interaction. Using first-principles quantum dynamics simulations, we reveal details of how electrons are dynamically excited through non-equilibrium energy transfer from highly energetic protons in liquid water on the atto/femto-second time scale. Water molecules along the path of the energetic proton undergo ionization at individual molecular level, and the excitation primarily derives from lone pair electrons on the oxygen atom of water molecules. A reduced charge state on the energetic proton in the condensed phase of water results in the strongly suppressed electronic response when compared to water molecules in the gas phase. These molecular-level findings provide important insights into understanding the water radiolysis process under proton irradiation.

  4. Calculated distance distributions of energy transfer events in irradiated liquid water

    SciTech Connect

    Hamm, R.N.; Turner, J.E.; Wright, H.A.; Ritchie, R.H.

    1980-01-01

    Histories from a Monte Carlo electron transport calculation in liquid water are analyzed to obtain the distance distribution functions, t(x) and T(x), of energy transfer events. These functions, which give the average energy transferred within a distance x from an arbitrary transfer event, are presented for irradiation by monoenergetic electrons of several energies between 500 eV and 1 MeV, for monoenergetic photons of 10, 50, and 200 keV energy and for 65 kVp and 200 kVp x rays and /sup 60/Co..gamma.. rays. The dose average lineal energy in spherical sites as a function of site radius is also presented for these same photon spectra.

  5. Effects of nonthermal plasma jet irradiation on the selective production of H2O2 and NO2- in liquid water

    NASA Astrophysics Data System (ADS)

    Uchida, Giichiro; Nakajima, Atsushi; Ito, Taiki; Takenaka, Kosuke; Kawasaki, Toshiyuki; Koga, Kazunori; Shiratani, Masaharu; Setsuhara, Yuichi

    2016-11-01

    We present the effects of the application of a nonthermal plasma jet to a liquid surface on H2O2 and NO2- generation in the liquid. Two distinct plasma irradiation conditions, with plasma contact and with no observable plasma contact with the liquid surface, were precisely compared. When the plasma was made to touch the liquid surface, the H2O2 concentration of the plasma-treated water was much higher than the NO2- concentration. In contrast, when no observable contact of the plasma with the liquid surface occurred, the ratio of the NO2- to H2O2 concentration became over 1 and NO2- became more dominant than H2O2 in the plasma-treated water. Our experiments clearly show that reactive oxygen and nitrogen species can be selectively produced in liquid using appropriate plasma-irradiation conditions of the liquid surface. The ratio of NO2- to H2O2 was controlled within a wide range of 0.02-1.2 simply by changing the plasma-irradiation distance from the liquid surface.

  6. IMPACT OF AEROSOL LIQUID WATER ON SECONDARY ORGANIC AEROSOL YIELDS OF IRRADIATED TOLUENE/PROPYLENE/NOX/(NH4)2SO4/AIR MIXUTRES

    EPA Science Inventory

    Laboratory experiments were conducted to assess whether the presence of liquid water on pre-existing submicron ammonium sulfate aerosols affects yields of condensible organic compounds. Toluene/propylene/NOX/air mixtures were irradiated in the presence of submicron ammonium su...

  7. IMPACT OF AEROSOL LIQUID WATER ON SECONDARY ORGANIC AEROSOL YIELDS OF IRRADIATED TOLUENE/PROPYLENE/NOX/(NH4)2SO4/AIR MIXUTRES

    EPA Science Inventory

    Laboratory experiments were conducted to assess whether the presence of liquid water on pre-existing submicron ammonium sulfate aerosols affects yields of condensible organic compounds. Toluene/propylene/NOX/air mixtures were irradiated in the presence of submicron ammonium su...

  8. Niobium-based sputtered thin films for corrosion protection of proton-irradiated liquid water targets for [18F] production

    NASA Astrophysics Data System (ADS)

    Skliarova, H.; Azzolini, O.; Cherenkova-Dousset, O.; Johnson, R. R.; Palmieri, V.

    2014-01-01

    Chemically inert coatings on Havar® entrance foils of the targets for [18F] production via proton irradiation of enriched water at pressurized conditions are needed to decrease the amount of ionic contaminants released from Havar®. In order to find the most effective protective coatings, the Nb-based coating microstructure and barrier properties have been correlated with deposition parameters such as substrate temperature, applied bias, deposition rate and sputtering gas pressure. Aluminated quartz used as a substrate allowed us to verify the protection efficiency of the desirable coatings as diffusion barriers. Two modelling corrosion tests based on the extreme susceptibility of aluminum to liquid gallium and acid corrosion were applied. Pure niobium coatings have been found to be less effective barriers than niobium-titanium coatings. But niobium oxide films, according to the corrosion tests performed, showed superior barrier properties. Therefore multi-layered niobium-niobium oxide films have been suggested, since they combine the high thermal conductivity of niobium with the good barrier properties of niobium oxide.

  9. On the nature and origin of dicationic, charge-separated species formed in liquid water on X-ray irradiation.

    PubMed

    Thürmer, Stephan; Ončák, Milan; Ottosson, Niklas; Seidel, Robert; Hergenhahn, Uwe; Bradforth, Stephen E; Slavíček, Petr; Winter, Bernd

    2013-07-01

    To understand the yield and patterns of damage in aqueous condensed matter, including biological systems, it is essential to identify the initial products subsequent to the interaction of high-energy radiation with liquid water. Until now, the observation of several fast reactions induced by energetic particles in water was not possible on their characteristic timescales. Therefore, some of the reaction intermediates involved, particularly those that require nuclear motion, were not considered when describing radiation chemistry. Here, through a combined experimental and theoretical study, we elucidate the ultrafast proton dynamics in the first few femtoseconds after X-ray core-level ionization of liquid water. We show through isotope analysis of the Auger spectra that proton-transfer dynamics occur on the same timescale as electron autoionization. Proton transfer leads to the formation of a Zundel-type intermediate [HO*···H···H2O](+), which further ionizes to form a so-far unnoticed type of dicationic charge-separated species with high internal energy. We call the process proton-transfer mediated charge separation.

  10. Vacuum electrospray of volatile liquids assisted by infrared laser irradiation.

    PubMed

    Ninomiya, Satoshi; Chen, Lee Chuin; Suzuki, Hiroaki; Sakai, Yuji; Hiraoka, Kenzo

    2012-04-15

    Current large cluster sources such as C(60) or argon utilize gas-phase sources which are of low-brightness and cannot be focused efficiently to better than 1 micron diameter spot size. The development of a high-brightness large cluster ion source is of critical importance to achieve high resolution in secondary ion mass spectrometry (SIMS) imaging of organics. We propose a new high-brightness large cluster ion source, and a technique for producing a stable electrospray of volatile liquids under vacuum. It is known that vacuum electrospray of volatile liquids such as water is extremely difficult because of freezing of the liquids introduced in vacuum by evaporative cooling. To avoid freezing, the tip of the electrospray emitter was irradiated by a continuous wave infrared laser. Without continuous laser irradiation the vacuum electrospray of a water/methanol solution was unstable with respect to the shapes of the Taylor cone and current, whereas continuous laser irradiation produced a stable electrospray of water. The typical modes of electrospray were clearly observed with an optical microscope even under vacuum conditions. A stable vacuum electrospray could be achieved by improving the vacuum pressure to suppress electric discharge and by using the laser to maintain the liquid state. This is the first description of the production of a stable vacuum electrospray of volatile liquids such as water. This vacuum electrospray technique can be expected to produce a novel high-brightness large cluster ion beam source. Copyright © 2012 John Wiley & Sons, Ltd.

  11. Laser ablation of liquid surface in air induced by laser irradiation through liquid medium

    NASA Astrophysics Data System (ADS)

    Utsunomiya, Yuji; Kajiwara, Takashi; Nishiyama, Takashi; Nagayama, Kunihito; Kubota, Shiro; Nakahara, Motonao

    2010-10-01

    The pulse laser ablation of a liquid surface in air when induced by laser irradiation through a liquid medium has been experimentally investigated. A supersonic liquid jet is observed at the liquid-air interface. The liquid surface layer is driven by a plasma plume that is produced by laser ablation at the layer, resulting in a liquid jet. This phenomenon occurs only when an Nd:YAG laser pulse (wavelength: 1064 nm) is focused from the liquid onto air at a low fluence of 20 J/cm2. In this case, as Fresnel’s law shows, the incident and reflected electric fields near the liquid surface layer are superposed constructively. In contrast, when the incident laser is focused from air onto the liquid, a liquid jet is produced only at an extremely high fluence, several times larger than that in the former case. The similarities and differences in the liquid jets and atomization processes are studied for several liquid samples, including water, ethanol, and vacuum oil. The laser ablation of the liquid surface is found to depend on the incident laser energy and laser fluence. A pulse laser light source and high-resolution film are required to observe the detailed structure of a liquid jet.

  12. Water: The Strangest Liquid

    SciTech Connect

    Nilsson, Anders

    2009-02-24

    Water, H2O, is familiar to everyone - it shapes our bodies and our planet. But despite its abundance, water has remained a mystery, exhibiting many strange properties that are still not understood. Why does the liquid have an unusually large capacity to store heat? And why is it denser than ice? Now, using the intense X-ray beams from particle accelerators, investigations into water are leading to fundamental discoveries about the structure and arrangement of water molecules. This lecture will elucidate the many mysteries of water and discuss current studies that are revolutionizing the way we see and understand one of the most fundamental substances of life.

  13. Photoresponsive liquid marbles and dry water.

    PubMed

    Tan, Tristan Tsai Yuan; Ahsan, Aniq; Reithofer, Michael R; Tay, Siok Wei; Tan, Sze Yu; Hor, Tzi Sum Andy; Chin, Jia Min; Chew, Benny Kia Jia; Wang, Xiaobai

    2014-04-01

    Stimuli-responsive liquid marbles for controlled release typically rely on organic moieties that require lengthy syntheses. We report herein a facile, one-step synthesis of hydrophobic and oleophobic TiO2 nanoparticles that display photoresponsive wettability. Water liquid marbles stabilized by these photoresponsive TiO2 particles were found to be stable when shielded from ultraviolet (UV) radiation; however, they quickly collapsed after being irradiated with 302 nm UV light. Oil- and organic-solvent-based liquid marbles could also be fabricated using oleophobic TiO2 nanoparticles and show similar UV-induced collapse. Finally, we demonstrated the formation of the micronized form of water liquid marbles, also known as dry water, by homogenization of the TiO2 nanoparticles with water. The TiO2 dry water displayed a similar photoresponse, whereby the micronized liquid marbles collapsed after irradiation and the dry water turned from a free-flowing powder to a paste. Hence, by exploiting the photoresponsive wettability of TiO2, we fabricated liquid marbles and dry water that display photoresponse and studied the conditions required for their collapse.

  14. Mars: occurrence of liquid water.

    PubMed

    Ingersoll, A P

    1970-05-22

    In the absence of juvenile liquid water, condensation of water vapor to ice and subsequent melting of ice are the only means of producing liquid water on the martian surface. However, the evaporation rate is so high that the available heat sources cannot melt pure ice. Liquid water is therefore limited to concentrated solutions of strongly deliquescent salts.

  15. Supercooled liquid water Estimation Tool

    SciTech Connect

    Roskovensky, John; Sallade, Jeff

    2012-05-04

    The Cloud Supercooled liquid water Estimation Tool (SEET) is a user driven Graphical User Interface (GUI) that estimates cloud supercooled liquid water (SLW) content in terms of vertical column and total mass from Moderate resolution Imaging Supercooled liquid water Estimation Tool Spectroradiometer (MODIS) spatially derived cloud products and realistic vertical cloud parameterizations that are user defined. It also contains functions for post-processing of the resulting data in tabular and graphical form.

  16. Comparison of chromatographic band profiles obtained under microwave irradiated and non-irradiated reversed-phase liquid chromatography column

    SciTech Connect

    Galinada, Wilmer; Guiochon, Georges A

    2005-08-01

    The possible influence of the application of microwave energy to a reversed-phase liquid chromatography column on the mass transfer kinetics and the thermodynamics of equilibrium between mobile and stationary phases was examined. Chromatograms of propylbenzene and phenol were recorded under the same experimental conditions, on the same column, successively irradiated and not. The effect of microwave irradiation on the mass transfer kinetics was determined by measuring the second moment of small pulses of propylbenzene in a 70:30 (v/v) solution of methanol in water and microwave outputs of 15 and 30 W. The effect of microwave irradiation on the equilibrium thermodynamics was determined by measuring the elution time of breakthrough curves of phenol at high concentrations in a 20:80 (v/v) solution of methanol and water and microwave outputs of 15, 50, and 150 W. A qualitative comparison of the profiles of the propylbenzene peaks obtained with and without irradiation suggests that this irradiation affects significantly the peak shapes. However, a qualitative comparison of the profiles of the breakthrough curves of phenol obtained with and without irradiation suggests that this irradiation has no significant effect on their shapes. The peak sharpening observed may be due to an increase in the diffusivity, resulting from the dielectric polarization under microwave irradiation. This effect is directly related to an increase of the rate of mass transfers in the column. In contrast, the similarity of the overloaded band profiles at high concentrations suggests that the equilibrium thermodynamics is unaffected by microwave irradiation. This may be explained by the transparence of the stationary phase to microwaves at 2.45 GHz. The column temperature was measured at the column outlet under irradiation powers of 15, 30, 50, and 150 W. It increases with increasing power, the corresponding effluent temperatures being 25 {+-} 1, 30 {+-} 1, 35 {+-} 1, and 45 {+-} 1 C, respectively.

  17. Molecular dynamics simulation analysis of ion irradiation effects on plasma-liquid interface

    NASA Astrophysics Data System (ADS)

    Minagawa, Yudai; Shirai, Naoki; Uchida, Satoshi; Tochikubo, Fumiyoshi

    2013-09-01

    Nonthermal atmospheric plasmas are used in a wide range of fields because the high-density plasma can be easily irradiated to various substances such as solid, liquid, biological object and so on. On the other hand, the mechanisms of physical and chemical phenomena at the plasma-liquid interface are not well understood yet. To investigate the effects of ion impact from plasma on water surface, we analyzed behavior of liquid water by classical molecular dynamics simulation. Simulation system consists of an irradiation particle in gas phase and 2000 water molecules in liquid phase. O+ ion with 10 eV or 100 eV was impinged on the water surface. Ion impact induced increasing water temperature and ejection of water molecules. The averaged number of evaporated water molecules by ion impact is 0.6 molecules at 10 eV and 7.0 molecules at 100 eV. The maximum ion penetration depth was 1.14 nm at 10 eV and 2.75 nm at 100 eV. Ion entering into water disturbs the stable hydrogen bonding configurations between water molecules and gives energy to water molecules. Some water molecules rotated and moved by ion interaction impact on other water molecules one after another. When the water molecule near the surface received strongly repulsive force, it released into gas phase. This work was supported financially in part by a Grant-in-Aid for Scientific Research on Innovation Areas (No21110007) from MEXT, Japan.

  18. Liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry for the analysis of sulfaquinoxaline byproducts formed in water upon solar light irradiation.

    PubMed

    Le Fur, C; Legeret, B; de Sainte Claire, P; Wong-Wah-Chung, P; Sarakha, M

    2013-03-30

    Sulfonamides such as sulfaquinoxaline (SQX) are among the most important antibiotic families due to their extensive use in veterinary medicine. The prediction of their fate under solar irradiation through the identification of the generated metabolites is required. However, unambiguous structural characterizations often remain a challenge particularly when several isomers could match with the same MS(2) data. Liquid chromatography/electrospray ionization quadrupole time-of-flight mass spectrometry (LC/ESI-Q-TOFMS) in the positive ion mode, leading to the formation of the protonated forms of the studied compounds, [M + H(+)] ions, was employed. Collision-induced dissociation tandem mass spectrometry (CID-MS/MS) of the protonated molecules was carried out, and the effect of the collision energy as well as the elemental compositions of the product ions were used to propose chemical structures. Validation of the hypothesized structures was performed by the calculation of key fragmentation pathway energies using density functional theory (DFT) calculations (B3LYP/6-31 G (d,p)). The photoproducts were identified as 2-aminoquinoxaline, SQX isomers, 2-(N-parabenzoquinoneimine)quinoxaline and isomers resulting from SO(2) extrusion. The direct fragmentations of [SQX + H](+) and its protonated isomers mostly occurred through the loss of 2-aminoquinoxaline and/or the 4-sulfoaniline radical ion, while their rearrangements involved the migration of H and/or O atoms. For the desulfonated byproducts in their protonated forms, the main neutral losses were of the quinoxaline radical, aminoquinoxaline and NH(3). The fragmentation of the protonated 2-aminoquinoxaline mainly involved the elimination of NH(3) and HCN. LC/ESI-Q-TOFMS and DFT calculations have been shown to be useful and complementary methods for the identification of unknown isomeric compounds and the elucidation of fragmentation patterns, in the case of the sulfaquinoxaline veterinary antibiotic. Copyright

  19. Liquid Water Restricts Habitability in Extreme Deserts

    NASA Astrophysics Data System (ADS)

    Cockell, Charles S.; Brown, Sarah; Landenmark, Hanna; Samuels, Toby; Siddall, Rebecca; Wadsworth, Jennifer

    2017-04-01

    Liquid water is a requirement for biochemistry, yet under some circumstances it is deleterious to life. Here, we show that liquid water reduces the upper temperature survival limit for two extremophilic photosynthetic microorganisms (Gloeocapsa and Chroococcidiopsis spp.) by greater than 40°C under hydrated conditions compared to desiccated conditions. Under hydrated conditions, thermal stress causes protein inactivation as shown by the fluorescein diacetate assay. The presence of water was also found to enhance the deleterious effects of freeze-thaw in Chroococcidiopsis sp. In the presence of water, short-wavelength UV radiation more effectively kills Gloeocapsa sp. colonies, which we hypothesize is caused by factors including the greater penetration of UV radiation into hydrated colonies compared to desiccated colonies. The data predict that deserts where maximum thermal stress or irradiation occurs in conjunction with the presence of liquid water may be less habitable to some organisms than more extreme arid deserts where organisms can dehydrate prior to being exposed to these extremes, thus minimizing thermal and radiation damage. Life in extreme deserts is poised between the deleterious effects of the presence and the lack of liquid water.

  20. Liquid Water Restricts Habitability in Extreme Deserts.

    PubMed

    Cockell, Charles S; Brown, Sarah; Landenmark, Hanna; Samuels, Toby; Siddall, Rebecca; Wadsworth, Jennifer

    2017-04-01

    Liquid water is a requirement for biochemistry, yet under some circumstances it is deleterious to life. Here, we show that liquid water reduces the upper temperature survival limit for two extremophilic photosynthetic microorganisms (Gloeocapsa and Chroococcidiopsis spp.) by greater than 40°C under hydrated conditions compared to desiccated conditions. Under hydrated conditions, thermal stress causes protein inactivation as shown by the fluorescein diacetate assay. The presence of water was also found to enhance the deleterious effects of freeze-thaw in Chroococcidiopsis sp. In the presence of water, short-wavelength UV radiation more effectively kills Gloeocapsa sp. colonies, which we hypothesize is caused by factors including the greater penetration of UV radiation into hydrated colonies compared to desiccated colonies. The data predict that deserts where maximum thermal stress or irradiation occurs in conjunction with the presence of liquid water may be less habitable to some organisms than more extreme arid deserts where organisms can dehydrate prior to being exposed to these extremes, thus minimizing thermal and radiation damage. Life in extreme deserts is poised between the deleterious effects of the presence and the lack of liquid water. Key Words: Deserts-Extremophiles-Stress-High temperatures-UV radiation-Desiccation. Astrobiology 17, 309-318.

  1. Liquid egg white pasteurization using a centrifugal UV irradiator

    USDA-ARS?s Scientific Manuscript database

    Studies are lacking on UV nonthermal pasteurization of liquid egg white (LEW). The objective of this study was to inactivate Escherichia coli using a UV irradiator that centrifugally formed a thin film of LEW on the inside of a rotating cylinder. The LEW was inoculated with E. coli K12 to approximat...

  2. ESR detection procedure of irradiated papaya containing high water content

    NASA Astrophysics Data System (ADS)

    Kikuchi, Masahiro; Shimoyama, Yuhei; Ukai, Mitsuko; Kobayashi, Yasuhiko

    2011-05-01

    ESR signals were recorded from irradiated papaya at liquid nitrogen temperature (77 K), and freeze-dried irradiated papaya at room temperature (295 K). Two side peaks from the flesh at the liquid nitrogen temperature indicated a linear dose response for 3-14 days after the γ-irradiation. The line shapes recorded from the freeze-dried specimens were sharper than those at liquid nitrogen temperature.

  3. Nanoscale heating of laser irradiated single gold nanoparticles in liquid.

    PubMed

    Honda, Mitsuhiro; Saito, Yuika; Smith, Nicholas I; Fujita, Katsumasa; Kawata, Satoshi

    2011-06-20

    Biological applications where nanoparticles are used in a cell environment with laser irradiation are rapidly emerging. Investigation of the localized heating effect due to the laser irradiation on the particle is required to preclude unintended thermal effects. While bulk temperature rise can be determined using macroscale measurement methods, observation of the actual temperature within the nanoscale domain around the particle is difficult and here we propose a method to measure the local temperature around a single gold nanoparticle in liquid, using white light scattering spectroscopy. Using 40-nm-diameter gold nanoparticles coated with thermo-responsive polymer, we monitored the localized heating effect through the plasmon peak shift. The shift occurs due to the temperature-dependent refractive index change in surrounding polymer medium. The results indicate that the particle experiences a temperature rise of around 10 degrees Celsius when irradiated with tightly focused irradiation of ~1 mW at 532 nm.

  4. Is Every Transparent Liquid Water?

    NASA Astrophysics Data System (ADS)

    Hugerat, Muhamad; Basheer, Sobhi

    2001-08-01

    The accepted description for water in schools worldwide is a transparent and colorless liquid. Since students in lower grades (ages 8-13) often see warning signs "Do not drink this liquid--it is not water", we believe that presenting experiments that demonstrate the inadequacy of the accepted description for water would be beneficial for teachers and their students to practice in their schools. These activities provide simple experiments that introduce students to important characteristics of different compounds that have similar external appearance. The characteristics presented here include polarity, electric conductivity, color change due to presence of an acid-base indicator, and electrolysis.

  5. WATER COLUMN DATA AND SPECTRAL IRRADIANCE MODEL

    EPA Science Inventory

    Water samples collected monthly, for 18 months, from six sites in the Laguna Madre were analyzed to identify and quantify phytopigments using High Performance Liquid Chromatography (HPLC). In addition, water column pigment and nutrient data were acquired at 12 stations in Upper ...

  6. WATER COLUMN DATA AND SPECTRAL IRRADIANCE MODEL

    EPA Science Inventory

    Water samples collected monthly, for 18 months, from six sites in the Laguna Madre were analyzed to identify and quantify phytopigments using High Performance Liquid Chromatography (HPLC). In addition, water column pigment and nutrient data were acquired at 12 stations in Upper ...

  7. Static heterogeneities in liquid water

    NASA Astrophysics Data System (ADS)

    Stanley, H. Eugene; Buldyrev, Sergey V.; Giovambattista, Nicolas

    2004-10-01

    The thermodynamic behavior of water seems to be closely related to static heterogeneities. These static heterogeneities are related to the local structure of water molecules, and when properly characterized, may offer an economical explanation of thermodynamic data. The key feature of liquid water is not so much that the existence of hydrogen bonds, first pointed out by Linus Pauling, but rather the local geometry of the liquid molecules is not spherical or oblong but tetrahedral. In the consideration of static heterogeneities, this local geometry is critical. Recent experiments suggested more than one phase of amorphous solid water, while simulations suggest that one of these phases is metastable with respect to another, so that in fact there are only two stable phases.

  8. Twin Astir: An irradiation experiment in liquid Pb Bi eutectic environment

    NASA Astrophysics Data System (ADS)

    Van den Bosch, J.; Al Mazouzi, A.; Benoit, Ph.; Bosch, R. W.; Claes, W.; Smolders, B.; Schuurmans, P.; Abderrahim, H. Aït

    2008-06-01

    The Twin Astir irradiation program, currently under irradiation in the BR2 reactor at SCK.CEN is aimed at determining the separate and possibly synergetic effects of a liquid lead bismuth eutectic (LBE) environment and neutron irradiation. It will lead to a parameterisation of the key influencing factors on the mechanical properties of the candidate structural materials for the future experimental accelerator driven system (ADS). The experiment consists of six capsules containing mainly mini tensile samples and one capsule containing mini DCT's (disc shaped compact tension specimens). Three of the tensile containing capsules and half of the DCT containing capsule are filled each with approximately 20 ml of low oxygen (10 -6 wt%) LBE. To complete the filling of these capsules with LBE under controlled conditions a dedicated filling installation was constructed at SCK.CEN. The other three tensile containing capsules are subjected to PWR water conditions, in order to discriminate the effect of PbBi under irradiation from the effect of the irradiation itself. To extract the effect of the PbBi corrosion itself on the material properties, one of the capsules is undergoing the thermal cycles of the BR2 reactor without being subjected to irradiation. This results in a matrix of three irradiation doses in LBE (0, 1.5 and 2.5 dpa) and two environments (PbBi and PWR water conditions). Here we will present the detailed concept and the status of the Twin Astir project, describe the materials under irradiation and report on our experience with the licensing of the experiment.

  9. Influence of plasmon coupling on the photoluminescence of ZnS/Ag nanoparticles obtained by laser irradiation in liquid

    NASA Astrophysics Data System (ADS)

    Moos, Rafaela; Graff, Ismael L.; de Oliveira, Vinicius S.; Schreiner, Wido H.; Bezerra, Arandi G.

    2017-10-01

    We investigate the photoluminescence, optical absorption and structural properties of ZnS submitted to laser irradiation in water and isopropyl alcohol. Nanoparticles were produced by irradiating micro-sized ZnS particles dispersed in both liquids, with and without the addition of Ag nanoparticles, taking advantage of the laser-assisted fragmentation effect. When ZnS microparticles are irradiated either in pure water or isopropyl alcohol a considerable size reduction is achieved (from micra to few nanometers). The photoluminescence of these nanoparticles mainly occurs in the UV, centered at 350 nm, and with smaller intensity in the visible, centered at 600 nm. Irradiation of ZnS microparticles dispersed in colloidal silver triggers a reaction between both materials, modifying its optical absorption and photoluminescent properties. After irradiation of ZnS in alcohol containing Ag nanoparticles, a giant increase of the UV photoluminescence is observed. Interestingly, when the irradiation is performed in aqueous Ag nanoparticles colloids, the photoluminescence suffers a red-shift towards the violet-blue. The data show that core-shell (Ag-ZnO) nanostructures are formed after irradiation and the visible emission likely originates from the ZnO shell grown around silver nanoparticles. The presence of Ag nanoparticles in the liquid medium promotes a stronger absorption of the laser beam during irradiation due to the coupling with the surface plasmon resonance, fostering intense reactions among ZnS, Ag nanoparticles, and the liquid medium. Our study shows that with a simple change of the liquid medium wherein the irradiation is conducted the photoluminescence can be tuned from UV to visible and core-shell nanostructures can be obtained.

  10. Inhomogeneities of stratocumulus liquid water

    NASA Technical Reports Server (NTRS)

    Cahalan, Robert F.; Snider, Jack B.

    1990-01-01

    There is a growing body of observational evidence on inhomogeneous cloud structure, most recently from the extensive measurements of the FIRE field program. Knowledge of cloud structure is important because it strongly influences the cloud radiative properties, one of the major factors in determining the global energy balance. Current atmospheric circulation models use plane-parallel radiation, so that the liquid water in each gridbox is assumed to be uniform, which gives an unrealistically large albedo. In reality cloud liquid water occupies only a subset of each gridbox, greatly reducing the mean albedo. If future climate models are to treat the hydrological cycle in a manner consistent with energy balance, a better treatment of cloud liquid is needed. FIRE concentrated upon two cloud types of special interest: cirrus and marine stratocumulus. Cirrus tend to be high and optically thin, thus reducing the effective radiative temperature without increasing the albedo significantly, leading to an enhanced greenhouse heating. In contrast, marine stratocumulus are low and optically thick, thus producing a large increase in reflected radiation with a small change in emitted radiation, giving a net cooling which could potentially mitigate the expected greenhouse warming. The FIRE measurements in California stratocumulus during June and July of 1987 show variations in cloud liquid water on all scales. Such variations are associated with inhomogeneous entrainment, in which entrained dry air, rather than mixing uniformly with cloudy air, remains intact in blobs of all sizes, which decay only slowly by invasion of cloudy air. Two important stratocumulus observations are described, followed by a simple fractal model which reproduces these properties, and finally, the model radiative properties are discussed.

  11. Magnetization transfer in a partly deuterated lyotropic liquid crystal by single- and dual-frequency RF irradiations

    NASA Astrophysics Data System (ADS)

    Lee, Jae-Seung; Regatte, Ravinder R.; Jerschow, Alexej

    2017-08-01

    The mechanism of magnetization transfer (MT) in a lyotropic liquid crystal made of sodium dodecyl sulfate, decanol, and water molecules is investigated by using deuterated molecules and single- and dual-frequency RF irradiations. The resulting Z-spectra suggest that the decanol molecules are mainly responsible for the MT effects in this system, through proton exchange to water. This is further confirmed by monitoring the relaxation of dipolar order, which allows one to estimate the transfer rate of magnetization from decanol to water. The potential benefits of using dual-frequency RF irradiation for inducing MT effects are explored through numerical solutions to a MT model based on Provotorov's partial saturation theory.

  12. Ionic liquids influence on the surface properties of electron beam irradiated wood

    NASA Astrophysics Data System (ADS)

    Croitoru, Catalin; Patachia, Silvia; Doroftei, Florica; Parparita, Elena; Vasile, Cornelia

    2014-09-01

    In this paper, the influence of three imidazolium-based ionic liquids (1-butyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium hexafluorophosphate and 1-hexyl-3-methylimidazolium chloride) on the structure and surface properties of sycamore maple (Acer pseudoplatanus) veneers submitted to electron beam irradiation with a dose of 50 kGy has been studied by using Fourier transform infrared spectroscopy, as well as image, scanning electron microscopy/SEM/EDX, atomic force microscopy and contact angle analysis. The experimental results have proven that the studied ionic liquids determine a better preservation of the structural features of wood (cellulose crystallinity index and lignin concentration on the surface) as well as some of surface properties such as surface energy, roughness, color upon irradiation with electron beam, in comparison with the reference wood, but surface composition is changed by treatment with imidazolium-based ionic liquids mainly with 1-butyl-3-methylimidazolium tetrafluoroborate. Also, under electron beam irradiation covalent bonding of the imidazolium moiety to wood determines a higher resistance to water penetration and spreading on the surface.

  13. Geomorphologic evidence for liquid water

    USGS Publications Warehouse

    Masson, P.; Carr, M.H.; Costard, F.; Greeley, R.; Hauber, E.; Jaumann, R.

    2001-01-01

    Besides Earth, Mars is the only planet with a record of resurfacing processes and environmental circumstances that indicate the past operation of a hydrologic cycle. However the present-day conditions on Mars are far apart of supporting liquid water on the surface. Although the large-scale morphology of the Martian channels and valleys show remarkable similarities with fluid-eroded features on Earth, there are major differences in their size, small-scale morphology, inner channel structure and source regions indicating that the erosion on Mars has its own characteristic genesis and evolution. The different landforms related to fluvial, glacial and periglacial activities, their relations with volcanism, and the chronology of water-related processes, are presented.

  14. Density Fluctuations in Liquid Water

    NASA Astrophysics Data System (ADS)

    English, Niall J.; Tse, John S.

    2011-01-01

    The density distributions and fluctuations in grids of varying size in liquid water at ambient pressure, both above the freezing point and in the supercooled state, are analyzed from the trajectories obtained from large-scale molecular dynamics simulations. It is found that the occurrence of low- and high-density regions (LDL and HDL) is transient and their respective residence times are dependent on the size of the simulated system. The spatial extent of density-density correlation is found to be within 7 Å or less. The temporal existence of LDL and HDL arises as a result of natural density fluctuations of an equilibrium system. The density of bulk water at ambient conditions is homogenous.

  15. Depolarization of water in protic ionic liquids.

    PubMed

    Zahn, Stefan; Wendler, Katharina; Delle Site, Luigi; Kirchner, Barbara

    2011-09-07

    A mixture of the protic ionic liquid mono-methylammonium nitrate with 1.6 wt% water was investigated from Car-Parrinello molecular dynamics simulations. In contrast to imidazolium-based ionic liquids, the cation possesses strong directional hydrogen bonds to water and all hydrogen bonds in the mixture have a comparable strength. This results in a good incorporation of water into the hydrogen bond network of mono-methylammonium nitrate and a tetrahedral hydrogen bond coordination of water. Hence, one might expect a larger dipole moment of water in the investigated mixture compared to neat water due to the good hydrogen bond network incorporation and the charged vicinity of water in the protic ionic liquid. However, the opposite is observed pointing to strong electrostatic screening in protic ionic liquids. Additionally, the influence of water on the properties of the protic ionic liquid is discussed.

  16. Measurement of radiation damage of water-based liquid scintillator and liquid scintillator

    DOE PAGES

    Bignell, L. J.; Diwan, M. V.; Hans, S.; ...

    2015-10-19

    Liquid scintillating phantoms have been proposed as a means to perform real-time 3D dosimetry for proton therapy treatment plan verification. We have studied what effect radiation damage to the scintillator will have upon this application. We have performed measurements of the degradation of the light yield and optical attenuation length of liquid scintillator and water-based liquid scintillator after irradiation by 201 MeV proton beams that deposited doses of approximately 52 Gy, 300 Gy, and 800 Gy in the scintillator. Liquid scintillator and water-based liquid scintillator (composed of 5% scintillating phase) exhibit light yield reductions of 1.74 ± 0.55 % andmore » 1.31 ± 0.59 % after ≈ 800 Gy of proton dose, respectively. Some increased optical attenuation was observed in the irradiated samples, the measured reduction to the light yield is also due to damage to the scintillation light production. Based on our results and conservative estimates of the expected dose in a clinical context, a scintillating phantom used for proton therapy treatment plan verification would exhibit a systematic light yield reduction of approximately 0.1% after a year of operation.« less

  17. Measurement of radiation damage of water-based liquid scintillator and liquid scintillator

    SciTech Connect

    Bignell, L. J.; Diwan, M. V.; Hans, S.; Jaffe, D. E.; Rosero, R.; Vigdor, S.; Viren, B.; Worcester, E.; Yeh, M.; Zhang, C.

    2015-10-19

    Liquid scintillating phantoms have been proposed as a means to perform real-time 3D dosimetry for proton therapy treatment plan verification. We have studied what effect radiation damage to the scintillator will have upon this application. We have performed measurements of the degradation of the light yield and optical attenuation length of liquid scintillator and water-based liquid scintillator after irradiation by 201 MeV proton beams that deposited doses of approximately 52 Gy, 300 Gy, and 800 Gy in the scintillator. Liquid scintillator and water-based liquid scintillator (composed of 5% scintillating phase) exhibit light yield reductions of 1.74 ± 0.55 % and 1.31 ± 0.59 % after ≈ 800 Gy of proton dose, respectively. Some increased optical attenuation was observed in the irradiated samples, the measured reduction to the light yield is also due to damage to the scintillation light production. Based on our results and conservative estimates of the expected dose in a clinical context, a scintillating phantom used for proton therapy treatment plan verification would exhibit a systematic light yield reduction of approximately 0.1% after a year of operation.

  18. Effect of ionic liquid properties on lipase stabilization under microwave irradiation

    SciTech Connect

    Zhao, Hua; Baker, Gary A; Song, Zhiyan; Olubajo, Olarongbe; Zanders, Lavezza; Campbell, Sophia

    2009-01-01

    Ionic liquids (ILs) as neoteric solvents and microwave irradiation as alternative energy source are becoming two important tools for many enzymatic reactions. However, it is not well understood what properties of ILs govern the enzyme stabilization, and whether the microwave irradiation could activate enzymes in ILs. To tackle these two important issues, the synthetic activities of immobilized Candida antarctica lipase B (Novozyme 435) were examined in more than twenty ILs through microwave heating. Under microwave irradiation, enhanced enzyme activities were observed when the enzyme was surrounded by a layer of water molecules. However, such enhancement diminished when the reaction system was dried. To understand the effect of IL properties, the enzyme activities under microwave irradiation were correlated with the viscosity, polarity and hydrophobicity (log P) of ILs, respectively. The initial reaction rates bear no direct relationship with the viscosity and polarity (in terms of dielectric constant and EN T ) of ILs, but have a loose correlation (a bell curve) with log P values. The enzyme stabilization by ILs was explained from aspects of hydrogen-bond basicity of anions, dissolution of the enzyme, ionic association strength of anions, and substrate ground-state stabilization by ILs.

  19. Raman lidar observations of cloud liquid water.

    PubMed

    Rizi, Vincenzo; Iarlori, Marco; Rocci, Giuseppe; Visconti, Guido

    2004-12-10

    We report the design and the performances of a Raman lidar for long-term monitoring of tropospheric aerosol backscattering and extinction coefficients, water vapor mixing ratio, and cloud liquid water. We focus on the system's capabilities of detecting Raman backscattering from cloud liquid water. After describing the system components, along with the current limitations and options for improvement, we report examples of observations in the case of low-level cumulus clouds. The measurements of the cloud liquid water content, as well as the estimations of the cloud droplet effective radii and number densities, obtained by combining the extinction coefficient and cloud water content within the clouds, are critically discussed.

  20. Effects of irradiation distance on supply of reactive oxygen species to the bottom of a Petri dish filled with liquid by an atmospheric O2/He plasma jet

    NASA Astrophysics Data System (ADS)

    Kawasaki, Toshiyuki; Kusumegi, Shota; Kudo, Akihiro; Sakanoshita, Tomohiro; Tsurumaru, Takuya; Sato, Akihiro; Uchida, Giichiro; Koga, Kazunori; Shiratani, Masaharu

    2016-05-01

    The impact of irradiation distances on plasma jet-induced specific effects on the supply of reactive oxygen species (ROS) to the bottom of a Petri dish filled with liquid was investigated using a KI-starch gel reagent that can be employed as a ROS indicator even in water. O3 exposure experiments without plasma irradiation were also performed to elucidate the specific effects of the plasma jet. Relative concentrations of ROS transported to the bottom were evaluated using absorbance measurements. The results indicated that ROS supply to the bottom is markedly enhanced by the plasma jet irradiation at shorter irradiation distances, whereas similar results could not be obtained for the O3 exposure. In these cases, the liquid mixing in the depth direction was also enhanced by the plasma jet irradiation only, and the supply of reactive atomic oxygen to the liquid surface was markedly increased as well.

  1. Irradiation of shell egg on the physicochemical and functional properties of liquid egg white.

    PubMed

    Min, B; Nam, K C; Jo, C; Ahn, D U

    2012-10-01

    This study was aimed at determining the effect of irradiation of shell eggs on the physiochemical and functional properties of liquid egg white during storage. Color and textural parameters of irradiated liquid egg white after cooking were also determined. Shell eggs were irradiated at 0, 2.5, 5, or 10 kGy using a linear accelerator. Egg white was separated from yolk and stored in at 4°C up to 14 d. Viscosity, pH, turbidity, foaming properties, color, and volatile profile of liquid egg white, and color and texture properties of cooked egg white were determined at 0, 7, and 14 d of storage. Irradiation increased the turbidity but decreased viscosity of liquid egg white. Foaming capacity and foam stability were not affected by irradiation at lower dose (2.5 kGy), but were deteriorated at higher doses (≥5.0 kGy) of irradiation. Sulfur-containing volatiles were generated by irradiation and their amounts increased as the irradiation dose increased. However, the sulfur volatiles disappeared during storage under aerobic conditions. Lightness (L* value) and yellowness (b* value) decreased, but greenness (-a* value) increased in cooked egg white in irradiation dose-dependent manners. All textural parameters (hardness, adhesiveness, cohesiveness, chewiness, and resilience) of cooked egg white increased as the irradiation dose increased, but those changes were marginal. Our results indicated that irradiation of shell egg at lower doses (up to 2.5 kGy) had little negative impact on the physiochemical and functional properties of liquid egg white, but can improve the efficiency of egg processing due to its viscosity-lowering effect. Therefore, irradiation of shell eggs at the lower doses has high potential to be used by the egg processing industry to improve the safety of liquid egg without compromising its quality.

  2. Determination of effective droplet radius and optical depth of liquid water clouds over a tropical site in northern Thailand using passive microwave soundings, aircraft measurements and spectral irradiance data

    NASA Astrophysics Data System (ADS)

    Nimnuan, P.; Janjai, S.; Nunez, M.; Pratummasoot, N.; Buntoung, S.; Charuchittipan, D.; Chanyatham, T.; Chantraket, P.; Tantiplubthong, N.

    2017-08-01

    This paper presents an algorithm for deriving the effective droplet radius and optical depth of liquid water clouds using ground-based measurements, aircraft observations and an adiabatic model of cloud liquid water. The algorithm derives cloud effective radius and cloud optical depth over a tropical site at Omkoi (17.80°N, 98.43°E), Thailand. Monthly averages of cloud optical depth are highest in April (54.5), which is the month with the lowest average cloud effective radius (4.2 μm), both occurring before the start of the rainy season and at the end of the high contamination period. By contrast, the monsoon period extending from May to October brings higher cloud effective radius and lower cloud optical depth to the region on average. At the diurnal scale there is a gradual increase in average cloud optical depth and decrease in cloud effective radius as the day progresses.

  3. Dipolar correlations in liquid water

    SciTech Connect

    Zhang, Cui; Galli, Giulia

    2014-08-28

    We present an analysis of the dipolar correlations in water as a function of temperature and density and in the presence of simple ionic solutes, carried out using molecular dynamics simulations and empirical potentials. We show that the dipole-dipole correlation function of the liquid exhibits sizable oscillations over nanodomains of about 1.5 nm radius, with several isosbestic points as a function of temperature; the size of the nanodomains is nearly independent on temperature and density, between 240 and 400 K and 0.9 and 1.3 g/cm{sup 3}, but it is substantially affected by the presence of solvated ions. In the same range of thermodynamic conditions, the decay time (τ) of the system dipole moment varies by a factor of about 30 and 1.5, as a function of temperature and density, respectively. At 300 K, we observed a maximum in τ as a function of density, and a corresponding shallow maximum in the tetrahedral order parameter, in a range where the diffusion coefficient, the pressure and the dielectric constant increase monotonically.

  4. Degradation of crosslinked polyethylene in water by gamma-irradiation

    NASA Astrophysics Data System (ADS)

    Matsui, Tatsuro; Takano, Tadao; Takayama, Shigeru; Ito, Masayuki; Narisawa, Ikuo

    2002-02-01

    The degradation of crosslinked polyethylene by gamma-irradiation in water was studied. Change in the physical properties and the growth of carbonyl group after irradiation showed a good correlation. The degradation observed at 80°C is the least, and that at 60°C is the severest. The distribution of the oxidized layer in the sample was measured and was also calculated from the diffusion model using the observed parameters. Comparison of both results suggest that some products caused by gamma-irradiation of water supress the degradation of XLPE at 80°C.

  5. Liquid-liquid phase transitions in supercooled water studied by computer simulations of various water models.

    PubMed

    Brovchenko, Ivan; Geiger, Alfons; Oleinikova, Alla

    2005-07-22

    Liquid-liquid and liquid-vapor coexistence regions of various water models were determined by Monte Carlo (MC) simulations of isotherms of density fluctuation-restricted systems and by Gibbs ensemble MC simulations. All studied water models show multiple liquid-liquid phase transitions in the supercooled region: we observe two transitions of the TIP4P, TIP5P, and SPCE models and three transitions of the ST2 model. The location of these phase transitions with respect to the liquid-vapor coexistence curve and the glass temperature is highly sensitive to the water model and its implementation. We suggest that the apparent thermodynamic singularity of real liquid water in the supercooled region at about 228 K is caused by an approach to the spinodal of the first (lowest density) liquid-liquid phase transition. The well-known density maximum of liquid water at 277 K is related to the second liquid-liquid phase transition, which is located at positive pressures with a critical point close to the maximum. A possible order parameter and the universality class of liquid-liquid phase transitions in one-component fluids are discussed.

  6. Understanding the liquid-liquid (water-hexane) interface

    NASA Astrophysics Data System (ADS)

    Murad, Sohail; Puri, Ishwar K.

    2017-10-01

    Nonequilibrium molecular dynamics simulations are employed to investigate the interfacial thermal resistance of nanoscale hexane-water interfaces subject to an applied heat flux. Our studies show that these liquid-liquid interfaces exhibit behavior significantly dissimilar to that of solid-liquid and solid-vapor interfaces. Notably, the thermal resistance of a hexane-water interface is contingent on the interfacial temperature gradient alone with negligible dependence on the mean interfacial temperature, while the solid-liquid dependent strongly on the interfacial temperature. Application of a heat flux also increases the interface thickness significantly as compared to an equilibrium isothermal interface. Since liquid-liquid interfaces have been proposed for diverse applications, e.g., sensors for wastewater treatment and for extraction of toxic ions from water, they can be designed to be wider by applying a heat flux. This may allow the interface to be used for other applications not possible currently because of the very limited thickness of the interface in isothermal systems.

  7. Correlation between irradiation conditions and nanoparticles obtained in case of laser ablation of aluminum targets in liquids

    NASA Astrophysics Data System (ADS)

    Damian, V.; Apostol, I.; Apostol, D.; Bojan, M.; Iordache, I.; Manoiu, S.; Militaru, A.; Udrea, C.

    2014-07-01

    The process of nanoparticles production by nanosecond pulsed laser ablation of aluminum targets situated in deionized water was studied from the point of view of laser-target interaction and incident laser fluence domain selection as a preliminary stage in the process of nanoparticles production. We have analyzed the irradiated surface morphology and crater profiles as a function of irradiation conditions (incident fluence and irradiation pulses number) by optical microscopy and white light interferometry in order to determine the most efficient coupling between the irradiation conditions and the irradiated surface immersed in liquid. The obtained nanoparticles were studied "in situ", as obtained in suspension in water and "ex situ", using TEM. TEM analyses have demonstrated that we have obtained nanoparticles with the lowest dimensions of 3-5 nm organized in clouds with dimensions between 40 and 80 nm. Typically the obtained nanoparticles presented two clear distributions, one corresponding to low diameters in the 6-10 or 20-40 nm regions, and another with a distribution around a maximum situated at hundreds of nanometers (250-290 nm). The obtained nanoparticles distribution was correlated with the irradiation conditions.

  8. Hydrogen generation by laser irradiation of colloids of iron and beryllium in water

    NASA Astrophysics Data System (ADS)

    Sukhov, I. A.; Shafeev, G. A.; Barmina, E. V.; Simakin, A. V.; Voronov, V. V.; Uvarov, O. V.

    2017-06-01

    The hydrogen generation under irradiation of aqueous colloids of iron and beryllium nanoparticles by 10-ns pulses of the first harmonic of a Nd : YAG laser with an energy density of about 80 J cm-2 in the solution is experimentally investigated. The partial hydrogen content in the atmosphere above the colloidal solutions of nanoparticles first increases with increasing irradiation time and then reaches a stationary level (400-500 Torr). The hydrogen generation rate, being nonzero in the case of irradiation of pure water, passes through a maximum with an increase in the nanoparticle concentration. The results obtained are discussed in terms of the dissociation of water molecules under a direct electron impact from the optical breakdown plasma formed in the liquid.

  9. Liquid egg white pasteurization using a centrifugal UV irradiator.

    PubMed

    Geveke, David J; Torres, Daniel

    2013-03-01

    Studies are limited on UV nonthermal pasteurization of liquid egg white (LEW). The objective of this study was to inactivate Escherichia coli using a UV irradiator that centrifugally formed a thin film of LEW on the inside of a rotating cylinder. The LEW was inoculated with E. coli K12 to approximately 8 log cfu/ml and was processed at the following conditions: UV intensity 1.5 to 9.0 mW/cm²; cylinder rotational speed 450 to 750 RPM, cylinder inclination angle 15° to 45°, and flow rate 300 to 900 ml/min, and treatment time 1.1 to 3.2s. Appropriate dilutions of the samples were pourplated with tryptic soy agar (TSA). Sublethal injury was determined using TSA+4% NaCl. The regrowth of surviving E. coli during refrigerated storage for 28 days was investigated. The electrical energy of the UV process was also determined. The results demonstrated that UV processing of LEW at a dose of 29 mJ/cm² at 10°C reduced E. coli by 5 log cfu/ml. Inactivation significantly increased with increasing UV dose and decreasing flow rate. The results at cylinder inclination angles of 30° and 45° were similar and were significantly better than those at 15°. The cylinder rotational speed had no significant effect on inactivation. The occurrence of sublethal injury was detected. Storage of UV processed LEW at 4° and 10°C for 21 days further reduced the population of E. coli to approximately 1 log cfu/ml where it remained for an additional 7 days. The UV energy applied to the LEW to obtain a 5 log reduction of E. coli was 3.9 J/ml. These results suggest that LEW may be efficiently pasteurized, albeit at low flow rates, using a nonthermal UV device that centrifugally forms a thin film.

  10. Determination of neutron energy spectra inside a water phantom irradiated by 64 MeV neutrons.

    PubMed

    Herbert, M S; Brooks, F D; Allie, M S; Buffler, A; Nchodu, M R; Makupula, S A; Jones, D T L; Langen, K M

    2007-01-01

    A NE230 deuterated liquid scintillator detector (25 mm diameter x 25 mm) has been used to investigate neutron energy spectra as a function of position in a water phantom under irradiation by a quasi-monoenergetic 64 MeV neutron beam. Neutron energy spectra are obtained from measurements of pulse height spectra by the NE230 detector using the Bayesian unfolding code MAXED. The experimentally measured energy spectra are compared with spectra calculated by Monte Carlo simulation using the code MCNPX.

  11. High-water-base hydraulic fluid-irradiation experiments

    SciTech Connect

    Bradley, E.C.; Meacham, S.A.

    1981-10-01

    A remote system for shearing spent nuclear fuel assemblies is being designed under the direction of the Consolidated Fuel Reprocessing Program (CFRP). The design incorporates a dual hydraulic fluid actuation system in which only one of the fluids, a high-water-base (HWBF), would be exposed to ionizing radiation and radioactive contamination. A commercially available synthetic, solution-type HWBF was selected as the reference. Single-sample irradiation experiments were conducted with three commercial fluids over a range of irradiation exposures. The physical and chemical properties of the irradiated HWBFs were analyzed and compared with unirradiated samples. In general, the results of the analyses showed increasing degradation of fluid properties with increasing irradiation dose. The results also indicated that a synthetic solution-type HWBF would perform satisfactorily in the remote shear system where irradiation doses up to 10/sup 6/ Gy (10/sup 8/ rad) are expected.

  12. Global Cloud Liquid Water Path Simulations(.

    NASA Astrophysics Data System (ADS)

    Lemus, Lilia; Rikus, Lawrie; Martin, C.; Platt, R.

    1997-01-01

    A new parameterization of cloud liquid water and ice content has been included in the Bureau of Meteorology Global Assimilation and Prediction System. The cloud liquid water content is derived from the mean cloud temperatures in the model using an empirical relationship based on observations. The results from perpetual January and July simulations are presented and show that the total cloud water path steadily decreases toward high latitudes, with two relative maxima at midlatitudes and a peak at low latitudes. To validate the scheme, the simulated fields need to be processed to produce liquid water paths that can be directly compared with the corresponding field derived from Special Sensor Microwave/Imager (SSM/I) data. This requires the identification of cloud ice water content within the parameterization and a prescription to account for the treatment of strongly precipitating subgrid-scale cloud. The resultant cloud liquid water paths agree qualitatively with the SSM/I data but show some systematic errors that are attributed to corresponding errors in the model's simulation of cloud amounts. Given that a more quantitative validation requires substantial improvement in the model's diagnostic cloud scheme, the comparison with the SSM/I data indicates that the cloud water path, derived from the cloud liquid water content parameterization introduced in this paper, is consistent with the observations and can be usefully incorporated in the prediction system.

  13. Evidence for Liquid Water on Comets

    NASA Technical Reports Server (NTRS)

    Sheldon, Robert; Hoover, Richard

    2005-01-01

    We have reexamined the arguments for the existence of liquid water on comets, and believe that recent cometary flybys along with pre-Giotto data support its presence on short-period comets. Liquid water would affect cometary dynamics, leaving distinct signatures in precession, orbital dynamics, and potential splitting of comets. Liquid water geysers would affect cometary atmosphere, dust evolution, and non-gravitational forces that perturb the orbit. Liquid water would affect the composition of both the interior and exterior of the comet, producing geologic effects consistent with recent flyby photographs. And most importantly, liquid water suppork the growth of lifeforms, which would make a comet a biofriendly incubator for interplanetary transport. The major objection against liquid water is the necessity of a pressure vessel to prevent sublimation into space. We discuss how such a pressure vessel could naturally evolve as a pristine comet makes its first journey inside the orbit of Mars, and suggest that this type of vessel was observed by Giotto, Deep Space I, and Stardust.

  14. Are There Two Forms of Liquid Water?

    NASA Astrophysics Data System (ADS)

    Stanley, H. E.

    We will introduce some of the 73 documented anomalies of the most complex of liquids, water--focusing on recent progress in understanding these anomalies by combining information provided by recent experiments and simulations on water in bulk, nanoconfined and biological environments designed to test the hypothesis that liquid water has behavior consistent with the novel phenomenon of ``liquid polymorphism'' in that water can exist in two distinct phases [1]. We will also discuss very recent work on nanoconfined water anomalies as well as the apparently related, and highly unusual, behavior of water in biological environments. Finally, we will discuss how the general concept of liquid polymorphism is proving useful in understanding anomalies in other liquids, such as silicon, silica, and carbon, as well as metallic glasses, which have in common that they are characterized by two characteristic length scales in their interactions.This work has been supported by the NSF Chemistry Division grant CHE-1213217 and was performed in collaboration with, among others, C. A. Angell, S. V. Buldyrev, S.-H. Chen, D. Corradini, P. G. Debenedetti, G. Franzese, P. Kumar, E. Lascaris, F. Mallamace, O. Mishima, P. H. Poole, S. Sastry, F. Sciortino, and L. Xu. H. E. Stanley, Editor, Liquid Polymorphism, Vol. 152 in Advances in Chemical Physics, S. A. Rice, Series Editor (Wiley, New York, 2013).

  15. Liquid water production from atmospheric sources

    NASA Astrophysics Data System (ADS)

    Matthews, John D.; Clarke, Norman P.

    1991-02-01

    The purpose of this effort was to assess the feasibility of developing a desiccant system to produce potable water from atmospheric sources that is compatible with military constraints. Goals were: (1) to examine desiccant technology, investigate methods of using available desiccants to collect atmospheric moisture, (2) develop a conceptual model of a desiccant water production system, and (3) develop a mathematical model to simulate the operation of the conceptual model. Results show that a desiccant system can produce large quantities of potable water using relatively small amounts of fuel for heat and fan power. The focus of this project was using a liquid desiccant (such as triethylene glycol) in an absorption-distillation cycle. This report documents the theoretical analysis of a hypothetical liquid desiccant based system for producing liquid water through collection of atmospheric moisture. Estimates are made of cost, weight and water production rate for the hypothetical system.

  16. Cleaning with water decomposed products obtained by laser irradiation

    NASA Astrophysics Data System (ADS)

    Hidai, Hirofumi; Tokura, Hitoshi

    2006-11-01

    ArF excimer laser irradiation can decompose water, and decomposed products contain highly reactive substrates, such as radicals. We propose cleaning using pure water with the aid of water decomposed products obtained by ArF excimer laser irradiation. In this study, the oxidation potential of decomposed products was estimated in metal etching. Then, cleaning of cutting oil was examined. The focal point of the lens used was set at the water surface. Specimens were aligned parallel to the laser beam, so that only decomposed products affected contaminants. As a result, decomposed products could not etch nickel and copper plates, but only zinc plates. Cutting oil was cleaned after 18 000 irradiation pulses. The range of the region cleaned was 5 mm around the focal point.

  17. Optimizing irradiance estimates for coastal and inland water imaging spectroscopy

    NASA Astrophysics Data System (ADS)

    Thompson, David R.; Seidel, Felix C.; Gao, Bo Cai; Gierach, Michelle M.; Green, Robert O.; Kudela, Raphael M.; Mouroulis, Pantazis

    2015-05-01

    Next generation orbital imaging spectrometers, with advanced global remote sensing capabilities, propose to address outstanding ocean science questions related to coastal and inland water environments. These missions require highly accurate characterization of solar irradiance in the critical 380-600 nm spectral range. However, the irradiance in this spectral region is temporally variable and difficult to measure directly, leading to considerable variance between different models. Here we optimize an irradiance estimate using data from the NASA airborne Portable Remote Imaging Spectrometer (PRISM), leveraging spectrally smooth in-scene targets. We demonstrate improved retrievals for both PRISM and the Next Generation Airborne Visible Infrared Imaging Spectrometer.

  18. Platinum nanostructures formed by femtosecond laser irradiation in water

    SciTech Connect

    Huo Haibin; Shen Mengyan

    2012-11-15

    Platinum nanostructures with various morphologies, such as spike-like, ripple-like and array-like structures, have been fabricated by 400 nm and 800 nm femtosecond laser irradiation in water. Different structures can be formed on the surfaces as a function of the laser wavelength, the fluence and scan methods. The reflectance measurements of these structures show much larger absorption on the irradiated surfaces than untreated platinum surfaces.

  19. The design of an irradiator for the continuous processing of liquid latex

    NASA Astrophysics Data System (ADS)

    Reuter, O.; Langley, R.; Zn, Wan Manshol Bin W.

    1998-06-01

    This paper presents anew design concept for a gamma irradiation plant for the continuous processing of pumpable liquids. Typical applications of such a plant include ∗ the irradiation vulcanisation of natural latex rubber ∗ disinfection of municipal sewage sludge for agricultural use ∗ sterilisation of liquids in the pharmaceutical and cosmetics industries ∗ industrial processing of bulk liquids The authors describe the design and operation of the latex irradiator now operating on a small production scale in Malaysia and proposed developments. The design allows irradiation processing to be carried out under an inert or other gaseous environment. State-of-the-art computer control system ensures the fully automatic processing operation needed by industrial computers.

  20. Properties of Water Confined in Ionic Liquids

    PubMed Central

    Saihara, Koji; Yoshimura, Yukihiro; Ohta, Soichi; Shimizu, Akio

    2015-01-01

    The varying states of water confined in the nano-domain structures of typical room temperature ionic liquids (ILs) were investigated by 1H NMR and by measurements of self-diffusion coefficients while systematically varying the IL cations and anions. The NMR peaks for water in BF4-based ILs were clearly split, indicating the presence of two discrete states of confined water (H2O and HOD). Proton and/or deuterium exchange rate among the water molecules was very slowly in the water-pocket. Notably, no significant changes were observed in the chemical shifts of the ILs. Self-diffusion coefficient results showed that water molecules exhibit a similar degree of mobility, although their diffusion rate is one order of magnitude faster than that of the IL cations and anions. These findings provide information on a completely new type of confinement, that of liquid water in soft matter. PMID:26024339

  1. Liquid chromatographic determination of water

    DOEpatents

    Fortier, Nancy E.; Fritz, James S.

    1990-11-13

    A sensitive method for the determination of water in the presence of common interferences is presented. The detection system is based on the effect of water on the equilibrium which results from the reaction aryl aldehydes, such as cinnamaldehyde and methanol in the eluent to form cinnamaldehyde dimethylacetal, plus water. This equilibrium is shifted in a catalytic atmosphere of a hydrogen ion form past column reactor. The extent of the shift and the resulting change in absorbance are proportional to the amount of water present.

  2. Liquid chromatographic determination of water

    DOEpatents

    Fortier, N.E.; Fritz, J.S.

    1990-11-13

    A sensitive method for the determination of water in the presence of common interferences is presented. The detection system is based on the effect of water on the equilibrium which results from the reaction aryl aldehydes, such as cinnamaldehyde and methanol in the eluent to form cinnamaldehyde dimethylacetal, plus water. This equilibrium is shifted in a catalytic atmosphere of a hydrogen ion form past column reactor. The extent of the shift and the resulting change in absorbance are proportional to the amount of water present. 1 fig.

  3. Liquid Water Oceans in Ice Giants

    NASA Technical Reports Server (NTRS)

    Wiktorowicz, Sloane J.; Ingersoll, Andrew P.

    2007-01-01

    Aptly named, ice giants such as Uranus and Neptune contain significant amounts of water. While this water cannot be present near the cloud tops, it must be abundant in the deep interior. We investigate the likelihood of a liquid water ocean existing in the hydrogen-rich region between the cloud tops and deep interior. Starting from an assumed temperature at a given upper tropospheric pressure (the photosphere), we follow a moist adiabat downward. The mixing ratio of water to hydrogen in the gas phase is small in the photosphere and increases with depth. The mixing ratio in the condensed phase is near unity in the photosphere and decreases with depth; this gives two possible outcomes. If at some pressure level the mixing ratio of water in the gas phase is equal to that in the deep interior, then that level is the cloud base. The gas below the cloud base has constant mixing ratio. Alternately, if the mixing ratio of water in the condensed phase reaches that in the deep interior, then the surface of a liquid ocean will occur. Below this ocean surface, the mixing ratio of water will be constant. A cloud base occurs when the photospheric temperature is high. For a family of ice giants with different photospheric temperatures, the cooler ice giants will have warmer cloud bases. For an ice giant with a cool enough photospheric temperature, the cloud base will exist at the critical temperature. For still cooler ice giants, ocean surfaces will result. A high mixing ratio of water in the deep interior favors a liquid ocean. We find that Neptune is both too warm (photospheric temperature too high) and too dry (mixing ratio of water in the deep interior too low) for liquid oceans to exist at present. To have a liquid ocean, Neptune s deep interior water to gas ratio would have to be higher than current models allow, and the density at 19 kbar would have to be approx. equal to 0.8 g/cu cm. Such a high density is inconsistent with gravitational data obtained during the Voyager

  4. Liquid Water Oceans in Ice Giants

    NASA Technical Reports Server (NTRS)

    Wiktorowicz, Sloane J.; Ingersoll, Andrew P.

    2007-01-01

    Aptly named, ice giants such as Uranus and Neptune contain significant amounts of water. While this water cannot be present near the cloud tops, it must be abundant in the deep interior. We investigate the likelihood of a liquid water ocean existing in the hydrogen-rich region between the cloud tops and deep interior. Starting from an assumed temperature at a given upper tropospheric pressure (the photosphere), we follow a moist adiabat downward. The mixing ratio of water to hydrogen in the gas phase is small in the photosphere and increases with depth. The mixing ratio in the condensed phase is near unity in the photosphere and decreases with depth; this gives two possible outcomes. If at some pressure level the mixing ratio of water in the gas phase is equal to that in the deep interior, then that level is the cloud base. The gas below the cloud base has constant mixing ratio. Alternately, if the mixing ratio of water in the condensed phase reaches that in the deep interior, then the surface of a liquid ocean will occur. Below this ocean surface, the mixing ratio of water will be constant. A cloud base occurs when the photospheric temperature is high. For a family of ice giants with different photospheric temperatures, the cooler ice giants will have warmer cloud bases. For an ice giant with a cool enough photospheric temperature, the cloud base will exist at the critical temperature. For still cooler ice giants, ocean surfaces will result. A high mixing ratio of water in the deep interior favors a liquid ocean. We find that Neptune is both too warm (photospheric temperature too high) and too dry (mixing ratio of water in the deep interior too low) for liquid oceans to exist at present. To have a liquid ocean, Neptune s deep interior water to gas ratio would have to be higher than current models allow, and the density at 19 kbar would have to be approx. equal to 0.8 g/cu cm. Such a high density is inconsistent with gravitational data obtained during the Voyager

  5. Liquid Water Production from Atmospheric Sources

    DTIC Science & Technology

    1991-02-01

    triethylene glycol ) in an absorption-distillation and a condenser. A desiccant is a material that has an cycle much like that used in the petroleum...the liquid surface and give up energy ture for many desiccants . Curves for triethylene glycol . Ihe to assume the liquid form. Equilibrium is defined as... desiccant cycle). Based on the toxicat anticipated that trace quantities of the desiccant would be levels for triethylene glycol , the corresponding water

  6. Water Contaminant Mitigation in Ionic Liquid Propellant

    NASA Technical Reports Server (NTRS)

    Conroy, David; Ziemer, John

    2009-01-01

    Appropriate system and operational requirements are needed in order to ensure mission success without unnecessary cost. Purity requirements applied to thruster propellants may flow down to materials and operations as well as the propellant preparation itself. Colloid electrospray thrusters function by applying a large potential to a room temperature liquid propellant (such as an ionic liquid), inducing formation of a Taylor cone. Ions and droplets are ejected from the Taylor cone and accelerated through a strong electric field. Electrospray thrusters are highly efficient, precise, scaleable, and demonstrate low thrust noise. Ionic liquid propellants have excellent properties for use as electrospray propellants, but can be hampered by impurities, owing to their solvent capabilities. Of foremost concern is the water content, which can result from exposure to atmosphere. Even hydrophobic ionic liquids have been shown to absorb water from the air. In order to mitigate the risks of bubble formation in feed systems caused by water content of the ionic liquid propellant, physical properties of the ionic liquid EMI-Im are analyzed. The effects of surface tension, material wetting, physisorption, and geometric details of the flow manifold and electrospray emitters are explored. Results are compared to laboratory test data.

  7. Water Contaminant Mitigation in Ionic Liquid Propellant

    NASA Technical Reports Server (NTRS)

    Conroy, David; Ziemer, John

    2009-01-01

    Appropriate system and operational requirements are needed in order to ensure mission success without unnecessary cost. Purity requirements applied to thruster propellants may flow down to materials and operations as well as the propellant preparation itself. Colloid electrospray thrusters function by applying a large potential to a room temperature liquid propellant (such as an ionic liquid), inducing formation of a Taylor cone. Ions and droplets are ejected from the Taylor cone and accelerated through a strong electric field. Electrospray thrusters are highly efficient, precise, scaleable, and demonstrate low thrust noise. Ionic liquid propellants have excellent properties for use as electrospray propellants, but can be hampered by impurities, owing to their solvent capabilities. Of foremost concern is the water content, which can result from exposure to atmosphere. Even hydrophobic ionic liquids have been shown to absorb water from the air. In order to mitigate the risks of bubble formation in feed systems caused by water content of the ionic liquid propellant, physical properties of the ionic liquid EMI-Im are analyzed. The effects of surface tension, material wetting, physisorption, and geometric details of the flow manifold and electrospray emitters are explored. Results are compared to laboratory test data.

  8. Using ultraviolet irradiation for removal of malathion pesticide in water.

    PubMed

    Shayeghi, M; Dehghani, Mh; Alimohammadi, M; Goodini, K

    2012-01-01

    Organophosphorus pesticides are one of the most consumable poisons. Such poisons can enter water sources by different routes. Since consuming some drinking water containing an amount of poison higher than the standard level, causes undesirable effects on human health. This research aimed to study the effectiveness of eliminating malathion from water by ultraviolet irradiation (UV) mercury lamp with a medium pressure. In this experimental- applied study, variants of initial pHs and initial concentrations and exposure times were investigated. Initial concentrations of malathion were 0.5, 1 and 2 mg/l. The samples were then exposed to UV irradiation interruptedly the time periods of 10, 20, 30, 40, 50 and 60 minutes. The UV lamp used in the reactor was medium pressure (irradiation intensity= 200 W/m(2)). The amounts of malathion were determined before and after the irradiation by HPLC instrument. Moreover, the results obtained from the study were analyzed using SPSS software and ANOVA and t-test statistical trials. The minimum reduction occurs at 10 min (46%) and the maximum reduction in 60 min (87.25%) (P< 0.05). In addition, the effectiveness of irradiation process decreases with increasing the poison concentration (P< 0.001). However, the efficiency of the process increases with pH increase. The results show the most effectiveness were achieved at 60 min and 0.5 mg/l and pH= 9. Therefore, the application of UV reactors could be considered as an appropriate method.

  9. Microwave-assisted liquid-liquid microextraction based on solidification of ionic liquid for the determination of sulfonamides in environmental water samples.

    PubMed

    Song, Ying; Wu, Lijie; Lu, Chunmei; Li, Na; Hu, Mingzhu; Wang, Ziming

    2014-12-01

    An easy, quick, and green method, microwave-assisted liquid-liquid microextraction based on solidification of ionic liquid, was first developed and applied to the extraction of sulfonamides in environmental water samples. 1-Ethy-3-methylimidazolium hexafluorophosphate, which is a solid-state ionic liquid at room temperature, was used as extraction solvent in the present method. After microwave irradiation for 90 s, the solid-state ionic liquid was melted into liquid phase and used to finish the extraction of the analytes. The ionic liquid and sample matrix can be separated by freezing and centrifuging. Several experimental parameters, including amount of extraction solvent, microwave power and irradiation time, pH of sample solution, and ionic strength, were investigated and optimized. Under the optimum experimental conditions, good linearity was observed in the range of 2.00-400.00 μg/L with the correlation coefficients ranging from 0.9995 to 0.9999. The limits of detection for sulfathiazole, sulfachlorpyridazine, sulfamethoxazole, and sulfaphenazole were 0.39, 0.33, 0.62, and 0.85 μg/L, respectively. When the present method was applied to the analysis of environmental water samples, the recoveries of the analytes ranged from 75.09 to 115.78% and relative standard deviations were lower than 11.89%. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Sources of variance of downwelling irradiance in water.

    PubMed

    Gege, Peter; Pinnel, Nicole

    2011-05-20

    The downwelling irradiance in water is highly variable due to the focusing and defocusing of sunlight and skylight by the wave-modulated water surface. While the time scales and intensity variations caused by wave focusing are well studied, little is known about the induced spectral variability. Also, the impact of variations of sensor depth and inclination during the measurement on spectral irradiance has not been studied much. We have developed a model that relates the variance of spectral irradiance to the relevant parameters of the environmental and experimental conditions. A dataset from three German lakes was used to validate the model and to study the importance of each effect as a function of depth for the range of 0 to 5 m.

  11. Water: A Tale of Two Liquids.

    PubMed

    Gallo, Paola; Amann-Winkel, Katrin; Angell, Charles Austen; Anisimov, Mikhail Alexeevich; Caupin, Frédéric; Chakravarty, Charusita; Lascaris, Erik; Loerting, Thomas; Panagiotopoulos, Athanassios Zois; Russo, John; Sellberg, Jonas Alexander; Stanley, Harry Eugene; Tanaka, Hajime; Vega, Carlos; Xu, Limei; Pettersson, Lars Gunnar Moody

    2016-07-13

    Water is the most abundant liquid on earth and also the substance with the largest number of anomalies in its properties. It is a prerequisite for life and as such a most important subject of current research in chemical physics and physical chemistry. In spite of its simplicity as a liquid, it has an enormously rich phase diagram where different types of ices, amorphous phases, and anomalies disclose a path that points to unique thermodynamics of its supercooled liquid state that still hides many unraveled secrets. In this review we describe the behavior of water in the regime from ambient conditions to the deeply supercooled region. The review describes simulations and experiments on this anomalous liquid. Several scenarios have been proposed to explain the anomalous properties that become strongly enhanced in the supercooled region. Among those, the second critical-point scenario has been investigated extensively, and at present most experimental evidence point to this scenario. Starting from very low temperatures, a coexistence line between a high-density amorphous phase and a low-density amorphous phase would continue in a coexistence line between a high-density and a low-density liquid phase terminating in a liquid-liquid critical point, LLCP. On approaching this LLCP from the one-phase region, a crossover in thermodynamics and dynamics can be found. This is discussed based on a picture of a temperature-dependent balance between a high-density liquid and a low-density liquid favored by, respectively, entropy and enthalpy, leading to a consistent picture of the thermodynamics of bulk water. Ice nucleation is also discussed, since this is what severely impedes experimental investigation of the vicinity of the proposed LLCP. Experimental investigation of stretched water, i.e., water at negative pressure, gives access to a different regime of the complex water diagram. Different ways to inhibit crystallization through confinement and aqueous solutions are

  12. Effect of Water on the Surface Composition of Irradiated Minerals

    NASA Astrophysics Data System (ADS)

    Dukes, C. A.; Baragiola, R. A.

    2010-03-01

    Sections of olivine and augite exposed to 10^17 Ar cm-2 ion irradiation and then rinsed in water or exposed to a humid enviornment show up to 60% depletion of surface cations. This has implications for sample return and curation.

  13. Electron irradiated liquid encapsulated Czochralski grown undoped gallium antimonide studied by positron lifetime spectroscopy and photoluminescence

    NASA Astrophysics Data System (ADS)

    Ma, S. K.; Lui, M. K.; Ling, C. C.; Fung, S.; Beling, C. D.; Li, K. F.; Cheah, K. W.; Gong, M.; Hang, H. S.; Weng, H. M.

    2004-09-01

    Electron irradiated undoped liquid encapsulated Czochralski (LEC) grown GaSb samples were studied by positron lifetime spectroscopy (PLS) and photoluminescence (PL). In addition to the 315 ps component reported in the previous studies, another defect with a lifetime of 280 ps was also identified in the present electron irradiated samples. The bulk lifetime of the GaSb material was found to be 258 ps. The VGa,280 ps and the VGa,315 ps defects were associated with two independent Ga vacancy related defects having different microstructures. The well known 777 meV PL signal (usually band A) was also observed in the electron irradiated undoped GaSb samples. The band A intensity decreases with increasing electron irradiation dosage and it disappears after the 300 °C annealing regardless of the irradiation dosage. The origin of the band A signal is also discussed.

  14. Detection of radiation-induced hydrocarbons in baked sponged cake prepared with irradiated liquid egg

    NASA Astrophysics Data System (ADS)

    Schulzki, G.; Spiegelberg, A.; Bögl, K. W.; Schreiber, G. A.

    1995-02-01

    For identification of irradiated food, radiation-induced volatile hydrocarbons (HC) are determined by gas chromatography in the non-polar fraction of fat. However, in complex food matrices the detection is often disturbed by fat-associated compounds. On-line coupling of high performance liquid chromatography (LC) and gas chromatography (GC) is very efficient to remove such compounds from the HC fraction. The high sensitivity of this fast and efficient technique is demonstrated by the example of detection of radiation-induced HC in fat isolated from baked sponge cake which had been prepared with irradiated liquid egg.

  15. An effective method to measure wall temperature of a liquid tank by laser irradiation

    NASA Astrophysics Data System (ADS)

    Jiao, Lu-guang; Zhao, Guo-min; Chen, Min-sun; Jiang, Hou-man

    2017-05-01

    Accurate measurement of the wall temperature is of great significance to investigate laser irradiation effects on a liquid tank. It was shown that the wall temperature couldn't be measured accurately using the traditional installation method for the thermocouple. To overcome this problem, an effective installation technique was developed. First, a groove was carved on the rear surface of the metal casing of a liquid tank by laser irradiation. Then the thermocouple junction was welded to the measurement point and covered up by high-temperature heat conduction glue. The experimental results showed that the wall temperature could be measured correctly using this installation technique.

  16. Water: A Tale of Two Liquids

    PubMed Central

    2016-01-01

    Water is the most abundant liquid on earth and also the substance with the largest number of anomalies in its properties. It is a prerequisite for life and as such a most important subject of current research in chemical physics and physical chemistry. In spite of its simplicity as a liquid, it has an enormously rich phase diagram where different types of ices, amorphous phases, and anomalies disclose a path that points to unique thermodynamics of its supercooled liquid state that still hides many unraveled secrets. In this review we describe the behavior of water in the regime from ambient conditions to the deeply supercooled region. The review describes simulations and experiments on this anomalous liquid. Several scenarios have been proposed to explain the anomalous properties that become strongly enhanced in the supercooled region. Among those, the second critical-point scenario has been investigated extensively, and at present most experimental evidence point to this scenario. Starting from very low temperatures, a coexistence line between a high-density amorphous phase and a low-density amorphous phase would continue in a coexistence line between a high-density and a low-density liquid phase terminating in a liquid–liquid critical point, LLCP. On approaching this LLCP from the one-phase region, a crossover in thermodynamics and dynamics can be found. This is discussed based on a picture of a temperature-dependent balance between a high-density liquid and a low-density liquid favored by, respectively, entropy and enthalpy, leading to a consistent picture of the thermodynamics of bulk water. Ice nucleation is also discussed, since this is what severely impedes experimental investigation of the vicinity of the proposed LLCP. Experimental investigation of stretched water, i.e., water at negative pressure, gives access to a different regime of the complex water diagram. Different ways to inhibit crystallization through confinement and aqueous solutions are

  17. Liquid-liquid phase transitions and water-like anomalies in liquids

    NASA Astrophysics Data System (ADS)

    Lascaris, Erik

    In this thesis we employ computer simulations and statistical physics to understand the origin of liquid-liquid phase transitions and their relationship with anomalies typical of liquid water. Compared with other liquids, water has many anomalies. For example the density anomaly: when water is cooled below 4 °C the density decreases rather than increases. This and other anomalies have also been found to occur in a few other one-component liquids, sometimes in conjunction with the existence of a liquid-liquid phase transition (LLPT) between a low-density liquid (LDL) and a high-density liquid (HDL). Using simple models we explain how these anomalies arise from the presence of two competing length scales. As a specific example we investigate the cut ramp potential, where we show the importance of "competition" in this context, and how one length scale can sometimes be zero. When there is a clear energetic preference for either LDL or HDL for all pressures and temperatures, then there is insufficient competition between the two liquid structures and no anomalies occur. From the simple models it also follows that anomalies can occur without the presence of a LLPT and vice versa. It remains therefore unclear if water has a LLPT that ends in a liquid-liquid critical point (LLCP), a hypothesis that was first proposed based on simulations of the ST2 water model. We confirm the existence of a LLCP in this model using finite size scaling and the Challa-Landau-Binder parameter, and show that the LLPT is not a liquid-crystal transition, as has recently been suggested. Previous research has indicated the possible existence of a LLCP in liquid silica. We perform a detailed analysis of two different silica models (WAC and BKS) at temperatures much lower than was previously simulated. Within the accessible temperature range we find no LLCP in either model, although in the case of WAC potential it is closely approached. We compare our results with those obtained for other

  18. Luminescence imaging of water during alpha particle irradiation

    NASA Astrophysics Data System (ADS)

    Yamamoto, Seiichi; Komori, Masataka; Koyama, Shuji; Toshito, Toshiyuki

    2016-05-01

    The luminescence imaging of water using the alpha particle irradiation of several MeV energy range is thought to be impossible because this alpha particle energy is far below the Cerenkov-light threshold and the secondary electrons produced in this energy range do not emit Cerenkov-light. Contrary to this consensus, we found that the luminescence imaging of water was possible with 5.5 MeV alpha particle irradiation. We placed a 2 MBq of 241Am alpha source in water, and luminescence images of the source were conducted with a high-sensitivity, cooled charge-coupled device (CCD) camera. We also carried out such imaging of the alpha source in three different conditions to compare the photon productions with that of water, in air, with a plastic scintillator, and an acrylic plate. The luminescence imaging of water was observed from 10 to 20 s acquisition, and the intensity was linearly increased with time. The intensity of the luminescence with the alpha irradiation of water was 0.05% of that with the plastic scintillator, 4% with air, and 15% with the acrylic plate. The resolution of the luminescence image of water was better than 0.25 mm FWHM. Alpha particles of 5.5 MeV energy emit luminescence in water. Although the intensity of the luminescence was smaller than that in air, it was clearly observable. The luminescence of water with alpha particles would be a new method for alpha particle detection and distribution measurements in water.

  19. [Effect of infrared laser irradiation on the arterial blood pressure in liquidators of the accident at the Chernobyl power plant].

    PubMed

    Korkushko, O O

    2003-01-01

    Liquidators of Tchernobyl accident with discirculatory post-irradiation encephalopathy were treated with infra-red lazer irradiation together with a half doze of pharmacological agents usually used. Infra-red lazer irradiation has been shown to result in a significant reduce in the arterial pressure level, so it can be effective in correcting the disturbances in haemodynamics.

  20. Theory of water and charged liquid bridges.

    PubMed

    Morawetz, K

    2012-08-01

    The phenomenon of liquid bridge formation due to an applied electric field is investigated. A solution of a charged catenary is presented, which allows one to determine the static and dynamical stability conditions where charged liquid bridges are possible. The creeping height, the bridge radius and length, as well as the shape of the bridge are calculated showing an asymmetric profile, in agreement with observations. The flow profile is calculated from the Navier-Stokes equation leading to a mean velocity, which combines charge transport with neutral mass flow and which describes recent experiments on water bridges.

  1. Using Ultraviolet Irradiation for Removal of Malathion Pesticide in Water

    PubMed Central

    Shayeghi, M; Dehghani, MH; Alimohammadi, M; Goodini, K

    2012-01-01

    Background Organophosphorus pesticides are one of the most consumable poisons. Such poisons can enter water sources by different routes. Since consuming some drinking water containing an amount of poison higher than the standard level, causes undesirable effects on human health. This research aimed to study the effectiveness of eliminating malathion from water by ultraviolet irradiation (UV) mercury lamp with a medium pressure. Methods: In this experimental- applied study, variants of initial pHs and initial concentrations and exposure times were investigated. Initial concentrations of malathion were 0.5, 1 and 2 mg/l. The samples were then exposed to UV irradiation interruptedly the time periods of 10, 20, 30, 40, 50 and 60 minutes. The UV lamp used in the reactor was medium pressure (irradiation intensity= 200 W/m2). The amounts of malathion were determined before and after the irradiation by HPLC instrument. Moreover, the results obtained from the study were analyzed using SPSS software and ANOVA and t-test statistical trials. Results: The minimum reduction occurs at 10 min (46%) and the maximum reduction in 60 min (87.25%) (P< 0.05). In addition, the effectiveness of irradiation process decreases with increasing the poison concentration (P< 0.001). However, the efficiency of the process increases with pH increase. Conclusion: The results show the most effectiveness were achieved at 60 min and 0.5 mg/l and pH= 9. Therefore, the application of UV reactors could be considered as an appropriate method. PMID:23293778

  2. Methodology of water quality index (WQI) development for filtrated water using irradiated basic filter elements

    NASA Astrophysics Data System (ADS)

    Anuar, Nuraslinda; Muhamad Pauzi, Anas; Abu Bakar, Asyraf Arif

    2017-01-01

    Clean water production can be achieved by using common simple water filtration system that consists of an empty bottle and the filter elements such as cotton/coffee filter, sands, and gravels, which can be easily assembled and used. To reduce the time to get an acceptably clean water using the common water filtration, this paper will discuss on a solution to increase the filtration effectiveness of the filter elements by irradiating gossypium (or commonly known as cotton), and silica oxide which is the main composition material for sand and gravel from various scale based on the Wentworth scale. There were few studies regarding gamma and neutron irradiation of silica based materials that proves that gamma and neutron irradiation introduce defects, hence, we expect that it may lead to the formation of micropores and alter the water filtration effectiveness. It was established that higher amount of irradiation results in higher concentration of defects. This paper will firstly review literatures on the effect of gamma and neutron irradiation effect on filter elements such as sands and papers, and then develops a water quality index (WQI) that reflects the water appearance quality of the filtrated water. The WQI focuses on the physical appearance such as smells and color of the filtered water.

  3. Surface reformation and electro-optical characteristics of liquid crystal alignment layers using ion beam irradiation

    SciTech Connect

    Oh, Byeong-Yun; Lee, Kang-Min; Kim, Byoung-Yong; Kim, Young-Hwan; Han, Jin-Woo; Han, Jeong-Min; Lee, Sang-Keuk; Seo, Dae-Shik

    2008-09-15

    The surface modification characteristics of liquid crystal (LC) alignment layers irradiated with various argon (Ar) ion beam (IB) energies were investigated as a substitute for rubbing technology. Various pretilt angles were created on the IB-irradiated polyimide (PI) surfaces after IB irradiation, but the Ar ions did not alter the morphology on the PI surface, indicating that the pretilt angle was not due to microgrooves. The chemical bonding states of the IB-irradiated PI surfaces were analyzed in detail by x-ray photoelectron spectroscopy to verify the compositional behavior for the LC alignment. Chemical structure analysis showed that the alignment ability of LCs was due to the preferential reorientation of the carbon network due to the breaking of C=O double bonds in the imide ring parallel to the incident IB direction. The potential of applying nonrubbing technology to display devices was further supported by the superior electro-optical characteristics compared to rubbed PI.

  4. Degradation of HT9 under simultaneous ion beam irradiation and liquid metal corrosion

    NASA Astrophysics Data System (ADS)

    Frazer, D.; Qvist, S.; Parker, S.; Krumwiede, D. L.; Caro, M.; Tesmer, J.; Maloy, S. A.; Wang, Y. Q.; Hosemann, P.

    2016-10-01

    A potentially promising coolant/structural material pair for a liquid-metal-cooled fast reactors is lead bismuth eutectic (LBE) coolant with the ferritic/martensitic steel HT9. The challenge of deploying LBE, however, is the corrosive environment it creates for structural materials. This corrosion can be mitigated with precise oxygen content control in the LBE to allow for the growth of passive protective oxide layers on the surface of the steel. In this paper, results are reported from the Irradiation Corrosion Experiment II (ICE-II), which allowed the simultaneous irradiation of a sample while in contact with LBE. It was found that a characteristic multilayer structure with an outer Fe3O4 oxide and inner FeCr2O4 spinel was grown and the oxidation was significantly larger in the irradiated region when compared to the region that was only exposed to LBE corrosion. Possible mechanisms are discussed to help understand this irradiation enhanced corrosion behavior.

  5. Liquid water habitats on early Mars

    NASA Technical Reports Server (NTRS)

    Mckay, Christopher P.; Davis, Wanda L.

    1992-01-01

    Although the Viking results may indicate that Mars has no life today, the possibility exists that Mars may hold the best record of the events that led to the origin of life. There is direct geomorphological evidence that in the past Mars had large amounts of liquid water on its surface. Atmospheric models would suggest that this early period of hydrological activity was due to the presence of a thick atmosphere and the resulting warmer temperatures. From a biological perspective the existence of liquid water by itself motivates the question of the origin of life on Mars. From studies of the Earth's earliest biosphere, we know that by 3.5 Gyr ago life had originated on Earth and reached a fair degree of biological sophistication. Surface activity and erosion on Earth make it difficult to trace the history of life before the 3.5 Gyr timeframe. If Mars did maintain a clement environment for longer than it took for life to originate on Earth, then the question of the origin of life on Mars follows naturally. Based upon simple models of the evolution of the Martian climate, we divide the history of liquid water habitats on the Martian surface into four epochs based upon the atmospheric temperature and pressure.

  6. Liquid water habitats on early Mars

    NASA Technical Reports Server (NTRS)

    Mckay, Christopher P.; Davis, Wanda L.

    1992-01-01

    Although the Viking results may indicate that Mars has no life today, the possibility exists that Mars may hold the best record of the events that led to the origin of life. There is direct geomorphological evidence that in the past Mars had large amounts of liquid water on its surface. Atmospheric models would suggest that this early period of hydrological activity was due to the presence of a thick atmosphere and the resulting warmer temperatures. From a biological perspective the existence of liquid water by itself motivates the question of the origin of life on Mars. From studies of the Earth's earliest biosphere, we know that by 3.5 Gyr ago life had originated on Earth and reached a fair degree of biological sophistication. Surface activity and erosion on Earth make it difficult to trace the history of life before the 3.5 Gyr timeframe. If Mars did maintain a clement environment for longer than it took for life to originate on Earth, then the question of the origin of life on Mars follows naturally. Based upon simple models of the evolution of the Martian climate, we divide the history of liquid water habitats on the Martian surface into four epochs based upon the atmospheric temperature and pressure.

  7. Photoelectron Emission Spectroscopy of Liquid Water.

    DTIC Science & Technology

    1981-04-01

    correlated to solvation free energies for H2O+(aq) and OH (aq)., DD ,FO*M 1473 EDITIOOF INOV so iS OBSOLETE Unclassified SECURITY CLASSIFICATION OF THIS PAGE...Photoelectron spectroscopy Reorganization free energy Water, liquid 20. ABSTRACT (Chlnw am ef We, aid* it nooe"mr and 1iEru’h hr 190k le 6) The threshold... energy Et a 10.06 eV (0.002 @V standard deviation) is detemined for phot~oelectron emission by litquid water and is correlated with Et a 8.45 eV for

  8. Separation of THF and water by room temperature ionic liquids.

    PubMed

    Hu, X; Yu, J; Liu, H

    2006-01-01

    Liquid-liquid equilibrium data are presented for mixtures of 1-(2-hydroxyethyl)-3-methylimidazolium chloride or tetrafluoroborate + tetrahydrofuran(THF) + water at 293.15 K. The data presented provides a valuable insight into how the environmentally friendly ionic liquid solvent can have the separation power of THF-water azeotropic systems. The sloping of the tie lines towards the THF vertex is investigated for mixtures of 1-(2-hydroxyethyl)-3-methylimidazolium chloride (or tetrafluoroborate) + THF + water. Selectivity values, derived from the tie line data, indicate that these two ionic liquids are suitable solvents for the liquid-liquid extraction of water from THF.

  9. Liquid water and active resurfacing on Europa

    NASA Technical Reports Server (NTRS)

    Squyres, S. W.; Reynolds, R. T.; Cassen, P. M.; Peale, S. J.

    1983-01-01

    Arguments for recent resurfacing of Europa by H2O from a liquid layer are presented, based on new interpretations of recent spacecraft and earth-based observations and revised theoretical calculations. The heat flow in the core and shell due to tidal forces is discussed, and considerations of viscosity and convection in the interior are found to imply water retention in the outer 60 km or so of the silicates, forming a layer of water/ice many tens of km thick. The outer ice crust is considered to be too thin to support heat transport rates sufficient to freeze the underlying water. Observational evidence for the calculations would consist of an insulating layer of frosts derived from water boiling up between cracks in the surface crust. Evidence for the existence of such a frost layer, including the photometric function of Europa and the deposits of sulfur on the trailing hemisphere, is discussed.

  10. Liquid water and active resurfacing on Europa

    NASA Technical Reports Server (NTRS)

    Squyres, S. W.; Reynolds, R. T.; Cassen, P. M.; Peale, S. J.

    1983-01-01

    Arguments for recent resurfacing of Europa by H2O from a liquid layer are presented, based on new interpretations of recent spacecraft and earth-based observations and revised theoretical calculations. The heat flow in the core and shell due to tidal forces is discussed, and considerations of viscosity and convection in the interior are found to imply water retention in the outer 60 km or so of the silicates, forming a layer of water/ice many tens of km thick. The outer ice crust is considered to be too thin to support heat transport rates sufficient to freeze the underlying water. Observational evidence for the calculations would consist of an insulating layer of frosts derived from water boiling up between cracks in the surface crust. Evidence for the existence of such a frost layer, including the photometric function of Europa and the deposits of sulfur on the trailing hemisphere, is discussed.

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

    SciTech Connect

    Kawasaki, Toshiyuki Kusumegi, Shota; Kudo, Akihiro; Sakanoshita, Tomohiro; Tsurumaru, Takuya; Sato, Akihiro; Uchida, Giichiro; Koga, Kazunori; Shiratani, Masaharu

    2016-05-07

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

  12. Thermodynamics of ice nucleation in liquid water.

    PubMed

    Wang, Xin; Wang, Shui; Xu, Qinzhi; Mi, Jianguo

    2015-01-29

    We present a density functional theory approach to investigate the thermodynamics of ice nucleation in supercooled water. Within the theoretical framework, the free-energy functional is constructed by the direct correlation function of oxygen-oxygen of the equilibrium water, and the function is derived from the reference interaction site model in consideration of the interactions of hydrogen-hydrogen, hydrogen-oxygen, and oxygen-oxygen. The equilibrium properties, including vapor-liquid and liquid-solid phase equilibria, local structure of hexagonal ice crystal, and interfacial structure and tension of water-ice are calculated in advance to examine the basis for the theory. The predicted phase equilibria and the water-ice surface tension are in good agreement with the experimental data. In particular, the critical nucleus radius and free-energy barrier during ice nucleation are predicted. The critical radius is similar to the simulation value, suggesting that the current theoretical approach is suitable in describing the thermodynamic properties of ice crystallization.

  13. Toxicity of irradiated advanced heavy water reactor fuels.

    PubMed

    Priest, N D; Richardson, R B; Edwards, G W R

    2013-02-01

    The good neutron economy and online refueling capability of the CANDU® heavy water moderated reactor (HWR) enable it to use many different fuels such as low enriched uranium (LEU), plutonium, or thorium, in addition to its traditional natural uranium (NU) fuel. The toxicity and radiological protection methods for these proposed fuels, unlike those for NU, are not well established. This study uses software to compare the fuel composition and toxicity of irradiated NU fuel against those of two irradiated advanced HWR fuel bundles as a function of post-irradiation time. The first bundle investigated is a CANFLEX® low void reactor fuel (LVRF), of which only the dysprosium-poisoned central element, and not the outer 42 LEU elements, is specifically analyzed. The second bundle investigated is a heterogeneous high-burnup (LEU,Th)O(2) fuelled bundle, whose two components (LEU in the outer 35 elements and thorium in the central eight elements) are analyzed separately. The LVRF central element was estimated to have a much lower toxicity than that of NU at all times after shutdown. Both the high burnup LEU and the thorium fuel had similar toxicity to NU at shutdown, but due to the creation of such inhalation hazards as (238)Pu, (240)Pu, (242)Am, (242)Cm, and (244)Cm (in high burnup LEU), and (232)U and (228)Th (in irradiated thorium), the toxicity of these fuels was almost double that of irradiated NU after 2,700 d of cooling. New urine bioassay methods for higher actinoids and the analysis of thorium in fecal samples are recommended to assess the internal dose from these two fuels.

  14. Liquid-liquid equilibrium of cholinium-derived bistriflimide ionic liquids with water and octanol.

    PubMed

    Costa, Anabela J L; Soromenho, Mário R C; Shimizu, Karina; Marrucho, Isabel M; Esperança, José M S S; Canongia Lopes, J N; Rebelo, Luís Paulo N

    2012-08-02

    The liquid-liquid equilibria of mixtures of cholinum-based ionic liquids (N-alkyl-N,N-dimethylhydroxyethylammonium bis(trifluoromethane)sulfonylimide, [N(11n2OH)][Ntf(2)], n = 1, 2, 3, 4, and 5) plus water or 1-octanol were investigated at atmospheric pressure over the entire composition range. The experiments were conducted between 265 and 385 K using the cloud-point method. The systems exhibit phase diagrams consistent with the existence of upper critical solution temperatures. The solubility of [N(1 1 n 2OH)][Ntf(2)] in water is lower for cations with longer alkyl side chains (larger n values). The corresponding trend in the octanol mixtures is reversed. The ([N(1 1 1 2OH)][Ntf(2)] + water + octanol) ternary system shows triple liquid-liquid immiscibility at room temperature and atmospheric pressure. A combined analytic/synthetic method was used to estimate the corresponding phase diagram under those conditions. Auxiliary molecular dynamics simulation data were used to interpret the experimental results at a molecular level.

  15. An Improved Liquid Water Absorption Model at Microwave Frequencies for Supercooled Liquid Water Clouds

    SciTech Connect

    Turner, D. D.; Kneifel, Stefan; Cadeddu, M. P.

    2016-01-01

    An improved liquid water absorption model is developed for frequencies between 0.5 and 500 GHz. The empirical coefficients for this model were retrieved from a dataset that consists of both laboratory observations of the permittivity of liquid water (primarily at temperatures above 0 degrees C) and field observations collected by microwave radiometers in three separate locations with observations at temperatures as low as -32 degrees C. An optimal estimation framework is used to retrieve the model's coefficients. This framework shows that there is high information content in the observations for seven of the nine model coefficients, but that the uncertainties in all of the coefficients result in less than 15% uncertainty in the liquid water absorption coefficient for all temperatures between -32 degrees and 0 degrees C and frequencies between 23 and 225 GHz. Furthermore, this model is more consistent with both the laboratory and field observations over all frequencies and temperatures than other popular absorption models.

  16. Metastable liquid-liquid transition in a molecular model of water

    NASA Astrophysics Data System (ADS)

    Palmer, Jeremy C.; Martelli, Fausto; Liu, Yang; Car, Roberto; Panagiotopoulos, Athanassios Z.; Debenedetti, Pablo G.

    2014-06-01

    Liquid water's isothermal compressibility and isobaric heat capacity, and the magnitude of its thermal expansion coefficient, increase sharply on cooling below the equilibrium freezing point. Many experimental, theoretical and computational studies have sought to understand the molecular origin and implications of this anomalous behaviour. Of the different theoretical scenarios put forward, one posits the existence of a first-order phase transition that involves two forms of liquid water and terminates at a critical point located at deeply supercooled conditions. Some experimental evidence is consistent with this hypothesis, but no definitive proof of a liquid-liquid transition in water has been obtained to date: rapid ice crystallization has so far prevented decisive measurements on deeply supercooled water, although this challenge has been overcome recently. Computer simulations are therefore crucial for exploring water's structure and behaviour in this regime, and have shown that some water models exhibit liquid-liquid transitions and others do not. However, recent work has argued that the liquid-liquid transition has been mistakenly interpreted, and is in fact a liquid-crystal transition in all atomistic models of water. Here we show, by studying the liquid-liquid transition in the ST2 model of water with the use of six advanced sampling methods to compute the free-energy surface, that two metastable liquid phases and a stable crystal phase exist at the same deeply supercooled thermodynamic condition, and that the transition between the two liquids satisfies the thermodynamic criteria of a first-order transition. We follow the rearrangement of water's coordination shell and topological ring structure along a thermodynamically reversible path from the low-density liquid to cubic ice. We also show that the system fluctuates freely between the two liquid phases rather than crystallizing. These findings provide unambiguous evidence for a liquid-liquid transition in

  17. Metastable liquid-liquid transition in a molecular model of water.

    PubMed

    Palmer, Jeremy C; Martelli, Fausto; Liu, Yang; Car, Roberto; Panagiotopoulos, Athanassios Z; Debenedetti, Pablo G

    2014-06-19

    Liquid water's isothermal compressibility and isobaric heat capacity, and the magnitude of its thermal expansion coefficient, increase sharply on cooling below the equilibrium freezing point. Many experimental, theoretical and computational studies have sought to understand the molecular origin and implications of this anomalous behaviour. Of the different theoretical scenarios put forward, one posits the existence of a first-order phase transition that involves two forms of liquid water and terminates at a critical point located at deeply supercooled conditions. Some experimental evidence is consistent with this hypothesis, but no definitive proof of a liquid-liquid transition in water has been obtained to date: rapid ice crystallization has so far prevented decisive measurements on deeply supercooled water, although this challenge has been overcome recently. Computer simulations are therefore crucial for exploring water's structure and behaviour in this regime, and have shown that some water models exhibit liquid-liquid transitions and others do not. However, recent work has argued that the liquid-liquid transition has been mistakenly interpreted, and is in fact a liquid-crystal transition in all atomistic models of water. Here we show, by studying the liquid-liquid transition in the ST2 model of water with the use of six advanced sampling methods to compute the free-energy surface, that two metastable liquid phases and a stable crystal phase exist at the same deeply supercooled thermodynamic condition, and that the transition between the two liquids satisfies the thermodynamic criteria of a first-order transition. We follow the rearrangement of water's coordination shell and topological ring structure along a thermodynamically reversible path from the low-density liquid to cubic ice. We also show that the system fluctuates freely between the two liquid phases rather than crystallizing. These findings provide unambiguous evidence for a liquid-liquid transition in

  18. Replacement of tritiated water from irradiated fuel storage bay

    SciTech Connect

    Castillo, I.; Boniface, H.; Suppiah, S.; Kennedy, B.; Minichilli, A.; Mitchell, T.

    2015-03-15

    Recently, AECL developed a novel method to reduce tritium emissions (to groundwater) and personnel doses at the NRU (National Research Universal) reactor irradiated fuel storage bay (also known as rod or spent fuel bay) through a water swap process. The light water in the fuel bay had built up tritium that had been transferred from the heavy water moderator through normal fuel transfers. The major advantage of the thermal stratification method was that a very effective tritium reduction could be achieved by swapping a minimal volume of bay water and warm tritiated water would be skimmed off the bay surface. A demonstration of the method was done that involved Computational Fluid Dynamics (CFD) modeling of the swap process and a test program that showed excellent agreement with model prediction for the effective removal of almost all the tritium with a minimal water volume. Building on the successful demonstration, AECL fabricated, installed, commissioned and operated a full-scale system to perform a water swap. This full-scale water swap operation achieved a tritium removal efficiency of about 96%.

  19. Effect of confinement on the liquid-liquid phase transition of supercooled water.

    PubMed

    Brovchenko, I; Oleinikova, A

    2007-06-07

    We report on an observation of the phase transition between two liquid phases of supercooled confined water in simulations. The temperature of the liquid-liquid transition of water at zero pressure slightly decreases due to confinement in the hydrophobic pore. The hydrophilic confinement affects this temperature in the opposite direction and shifts the critical point of the liquid-liquid transition to a higher pressure. As a result, in a strongly hydrophilic pore the liquid-liquid phase transition becomes continuous at zero pressure, indicating the shift of its critical point from negative to a positive pressure. These findings indicate that experimental studies of water confined in the pores of various hydrophobicity/hydrophilicity may clarify the location of the liquid-liquid critical point of bulk water.

  20. Liquid nanodroplet formation through phase explosion mechanism in laser-irradiated metal targets

    NASA Astrophysics Data System (ADS)

    Mazzi, Alberto; Gorrini, Federico; Miotello, Antonio

    2015-09-01

    Some quantitative aspects of laser-irradiated pure metals, while approaching phase explosion, are still not completely understood. Here, we develop a model that describes the main quantities regulating the liquid-vapor explosive phase transition and the expulsion of liquid nanodroplets that, by solidifying, give rise to nanoparticle formation. The model combines both a thermodynamics description of the explosive phase change and a Monte Carlo simulation of the randomly generated critical vapor bubbles. The calculation is performed on a set of seven metals (Al, Fe, Co, Ni, Cu, Ag, and Au) which are frequently used in pulsed laser ablation experiments. Our final predictions about the size distribution of the liquid nanodroplets and the number ratio of liquid/vapor ejected atoms are compared, whenever possible, with available molecular dynamics simulations and experimental data.

  1. Tribological coatings for liquid metal and irradiation environments

    SciTech Connect

    Johnson, R.N.

    1986-06-01

    Several metallurgical coatings have been developed that provide good tribological performances in high-temperature liquid sodium and that are relatively unaffected by neutron fluences to 6 X 10/sup 22/ n/cm/sup 2/ (E > 0.1 MeV). The coatings that have consistently provided the best tribological performance have been the nickel aluminide diffusion coatings created by the pack cementation process, chromium carbide or Tribaloy 700 trade mark (a nickel-base hardfacing alloy) applied by the detonation-gun process, and chromium carbide and other hardfacing alloy) applied by the detonation-gun process, and chromium carbide and other hardfacing materials applied by the electro-spark deposition process. The latter process is a relatively recent development for nuclear applications and is expected to find wide usage. Other coating processes, such as plasma-spray coating, sputtering, and chemical vapor deposition, were candidates for use on various components, but the coatings did not pass the required qualification tests or were not economically competitive. The advantages and limitations of the three selected processes are discussed, the tribological performance of the coatings is reviewed, and representative applications and their performance requirements are described.

  2. Triplet correlation functions in liquid water

    SciTech Connect

    Dhabal, Debdas; Chakravarty, Charusita; Singh, Murari; Wikfeldt, Kjartan Thor

    2014-11-07

    Triplet correlations have been shown to play a crucial role in the transformation of simple liquids to anomalous tetrahedral fluids [M. Singh, D. Dhabal, A. H. Nguyen, V. Molinero, and C. Chakravarty, Phys. Rev. Lett. 112, 147801 (2014)]. Here we examine triplet correlation functions for water, arguably the most important tetrahedral liquid, under ambient conditions, using configurational ensembles derived from molecular dynamics (MD) simulations and reverse Monte Carlo (RMC) datasets fitted to experimental scattering data. Four different RMC data sets with widely varying hydrogen-bond topologies fitted to neutron and x-ray scattering data are considered [K. T. Wikfeldt, M. Leetmaa, M. P. Ljungberg, A. Nilsson, and L. G. M. Pettersson, J. Phys. Chem. B 113, 6246 (2009)]. Molecular dynamics simulations are performed for two rigid-body effective pair potentials (SPC/E and TIP4P/2005) and the monatomic water (mW) model. Triplet correlation functions are compared with other structural measures for tetrahedrality, such as the O–O–O angular distribution function and the local tetrahedral order distributions. In contrast to the pair correlation functions, which are identical for all the RMC ensembles, the O–O–O triplet correlation function can discriminate between ensembles with different degrees of tetrahedral network formation with the maximally symmetric, tetrahedral SYM dataset displaying distinct signatures of tetrahedrality similar to those obtained from atomistic simulations of the SPC/E model. Triplet correlations from the RMC datasets conform closely to the Kirkwood superposition approximation, while those from MD simulations show deviations within the first two neighbour shells. The possibilities for experimental estimation of triplet correlations of water and other tetrahedral liquids are discussed.

  3. Triplet correlation functions in liquid water

    NASA Astrophysics Data System (ADS)

    Dhabal, Debdas; Singh, Murari; Wikfeldt, Kjartan Thor; Chakravarty, Charusita

    2014-11-01

    Triplet correlations have been shown to play a crucial role in the transformation of simple liquids to anomalous tetrahedral fluids [M. Singh, D. Dhabal, A. H. Nguyen, V. Molinero, and C. Chakravarty, Phys. Rev. Lett. 112, 147801 (2014)]. Here we examine triplet correlation functions for water, arguably the most important tetrahedral liquid, under ambient conditions, using configurational ensembles derived from molecular dynamics (MD) simulations and reverse Monte Carlo (RMC) datasets fitted to experimental scattering data. Four different RMC data sets with widely varying hydrogen-bond topologies fitted to neutron and x-ray scattering data are considered [K. T. Wikfeldt, M. Leetmaa, M. P. Ljungberg, A. Nilsson, and L. G. M. Pettersson, J. Phys. Chem. B 113, 6246 (2009)]. Molecular dynamics simulations are performed for two rigid-body effective pair potentials (SPC/E and TIP4P/2005) and the monatomic water (mW) model. Triplet correlation functions are compared with other structural measures for tetrahedrality, such as the O-O-O angular distribution function and the local tetrahedral order distributions. In contrast to the pair correlation functions, which are identical for all the RMC ensembles, the O-O-O triplet correlation function can discriminate between ensembles with different degrees of tetrahedral network formation with the maximally symmetric, tetrahedral SYM dataset displaying distinct signatures of tetrahedrality similar to those obtained from atomistic simulations of the SPC/E model. Triplet correlations from the RMC datasets conform closely to the Kirkwood superposition approximation, while those from MD simulations show deviations within the first two neighbour shells. The possibilities for experimental estimation of triplet correlations of water and other tetrahedral liquids are discussed.

  4. Quantification of C in Si by photoluminescence at liquid N temperature after electron irradiation

    NASA Astrophysics Data System (ADS)

    Tajima, Michio; Kiuchi, Hirotatsu; Higuchi, Fumito; Ogura, Atsushi

    2017-04-01

    We demonstrate practical great advantages of the photoluminescence (PL) measurement at liquid N temperature after electron irradiation for quantifying low-level C in Si compared with the measurement at liquid He temperature. The broadening of the C-related C- and G-lines enabled us to detect the lines rapidly with high sensitivity by using the optimized low-dispersion spectroscopic apparatus. Positive correlations were found between their intensity ratios to the band-edge emission and the C concentration estimated by PL measurement at 4.2 K. The disappearance of dopant-impurity-related lines simplifies the recombination process, suggesting the improvement of quantification accuracy.

  5. Liquid-liquid transition in ST2 water

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Palmer, Jeremy C.; Panagiotopoulos, Athanassios Z.; Debenedetti, Pablo G.

    2012-12-01

    We use the weighted histogram analysis method [S. Kumar, D. Bouzida, R. H. Swendsen, P. A. Kollman, and J. M. Rosenberg, J. Comput. Chem. 13, 1011 (1992), 10.1002/jcc.540130812] to calculate the free energy surface of the ST2 model of water as a function of density and bond-orientational order. We perform our calculations at deeply supercooled conditions (T = 228.6 K, P = 2.2 kbar; T = 235 K, P = 2.2 kbar) and focus our attention on the region of bond-orientational order that is relevant to disordered phases. We find a first-order transition between a low-density liquid (LDL, ρ ≈ 0.9 g/cc) and a high-density liquid (HDL, ρ ≈ 1.15 g/cc), confirming our earlier sampling of the free energy surface of this model as a function of density [Y. Liu, A. Z. Panagiotopoulos, and P. G. Debenedetti, J. Chem. Phys. 131, 104508 (2009), 10.1063/1.3229892]. We demonstrate the disappearance of the LDL basin at high pressure and of the HDL basin at low pressure, in agreement with independent simulations of the system's equation of state. Consistency between directly computed and reweighted free energies, as well as between free energy surfaces computed using different thermodynamic starting conditions, confirms proper equilibrium sampling. Diffusion and structural relaxation calculations demonstrate that equilibration of the LDL phase, which exhibits slow dynamics, is attained in the course of the simulations. Repeated flipping between the LDL and HDL phases in the course of long molecular dynamics runs provides further evidence of a phase transition. We use the Ewald summation with vacuum boundary conditions to calculate long-ranged Coulombic interactions and show that conducting boundary conditions lead to unphysical behavior at low temperatures.

  6. BLISTERING AND EXPLOSIVE DESORPTION OF IRRADIATED AMMONIA-WATER MIXTURES

    SciTech Connect

    Loeffler, M. J.; Baragiola, R. A. E-mail: raul@virginia.edu

    2012-01-10

    We present laboratory studies on the thermal evolution of a solid ammonia-water mixture after it has been irradiated at 20, 70, and 120 K. In samples irradiated at {<=}70 K, we observed fast outbursts that appear to indicate grain ejection and correlate well with the formation of micron-sized scattering centers. The occurrence of this phenomenon at the lower irradiation temperatures indicates that our results may be most relevant for understanding the release of gas and grains by comets and the surfaces of some of the colder icy satellites. We observe outgassing at temperatures below those where ice sublimates, which suggests that comets containing radiolyzed material may have outbursts farther from the Sun that those that are passive. In addition, the estimated size of the grains ejected from our sample is on the order of the size of E-ring particles, suggesting that our results give a plausible mechanism for how micron-sized grains could be formed from an icy surface. Finally, we propose that the presence of the {approx}4.5 {mu}m N{sub 2}O absorption band on an icy surface in outer space will serve to provide indirect evidence for radiation-processed ices that originally contained ammonia or nitrogen, which could be particularly useful since nitrogen is such a weak absorber in the infrared and ammonia is rapidly decomposed by radiolysis.

  7. Temperature oscillations in liquid media caused by continuous (nonmodulated) millimeter wavelength electromagnetic irradiation.

    PubMed

    Khizhnyak, E P; Ziskin, M C

    1996-01-01

    Convection in liquids caused by 53-78 GHz millimeter wave irradiation with incident power density that ranged from 10 microW/cm2 to 1 W/cm2 was studied. Infrared thermography was used as an artifact-free method for recording surface-temperature dynamics during irradiation. It was found that continuous (nonmodulated) waves can produce a relaxation-type temperature oscillation in liquids with a relatively high stability of the period between temperature spikes. The temperature oscillation is due to the repetitive formation and dissipation of a torroidal type of convection vortex. When the vortex became stable during irradiation, we observed a temperature decrease following the initial temperature-rise phase, even though the irradiation was constantly maintained. This result constitutes a new process that can play a significant role in producing microwave bioeffects, including some so-called "nonthermal" effects and some effects that are inversely related to heating. Also, it can be considered as a newly discovered potential artifact in microwave bioeffects studies.

  8. Determination of four heterocyclic insecticides by ionic liquid dispersive liquid-liquid microextraction in water samples.

    PubMed

    Liu, Yu; Zhao, Ercheng; Zhu, Wentao; Gao, Haixiang; Zhou, Zhiqiang

    2009-02-06

    A novel microextraction method termed ionic liquid dispersive liquid-liquid microextraction (IL-DLLME) combining high-performance liquid chromatography with diode array detection (HPLC-DAD) was developed for the determination of insecticides in water samples. Four heterocyclic insecticides (fipronil, chlorfenapyr, buprofezin, and hexythiazox) were selected as the model compounds for validating this new method. This technique combines extraction and concentration of the analytes into one step, and the ionic liquid was used instead of a volatile organic solvent as the extraction solvent. Several important parameters influencing the IL-DLLME extraction efficiency such as the volume of extraction solvent, the type and volume of disperser solvent, extraction time, centrifugation time, salt effect as well as acid addition were investigated. Under the optimized conditions, good enrichment factors (209-276) and accepted recoveries (79-110%) were obtained for the extraction of the target analytes in water samples. The calibration curves were linear with correlation coefficient ranged from 0.9947 to 0.9973 in the concentration level of 2-100 microg/L, and the relative standard deviations (RSDs, n=5) were 4.5-10.7%. The limits of detection for the four insecticides were 0.53-1.28 microg/L at a signal-to-noise ratio (S/N) of 3.

  9. Behavior of a SnLi liquid metal eutectic on D-irradiated, porous tungsten substrates

    NASA Astrophysics Data System (ADS)

    Lang, Eric; Kapat, Aveek; Allain, J. P.

    2016-10-01

    Tungsten (W) is a common PFC material in the divertor due to its beneficial thermomechanical properties and high sputter threshold. Under helium irradiation, W develops surface morphology such as fuzz. Liquid metals, such as tin-lithium eutectics, have been proposed as PFCs to combat W erosion and allow for a self-healing surface. Tin-dominant eutectics have lower evaporation rates than pure lithium due to increased binding energies, yet exhibit decreased D retention and Li surface segregation. In prior experiments of SnLi coatings on fuzzy W substrates, the SnLi layer has been shown to protect underlying fuzz. Additionally, the liquid metal better adhered to a fuzzy surface than a smooth one. Fuzzy W samples have been coated with a 95 at.% SnLi eutectic and exposed to 250eV D ions at elevated temperatures and fluences of 1017 cm-2 . Experiments will be conducted in the IGNIS facility, a multi-functional, in-situ irradiation and characterization facility at the University of Illinois. In-situ XPS will be used to elucidate irradiation-driven liquid metal behavior to identify surface chemistry changes. Additionally, ex-situSEM will be used to identify surface morphology changes. Work supported by US DOE Contract DE-SC0014267.

  10. Liquid water sill emplacement on Europa?

    NASA Astrophysics Data System (ADS)

    Craft, K.; Patterson, G. W.; Lowell, R. P.

    2013-12-01

    Recent work has suggested that lithospheric flexure and flanking fractures observed along some ridges on Europa are best explained by the initial presence of a shallow liquid water sill. The emplacement of a sill suggests certain conditions existed that were favorable to water flow from the ocean to the subsurface, stresses that allowed horizontal fracturing for sill emplacement, and liquid water replenishment to enable a sill lifetime of ~ 1000s of years. Here, we investigate whether these conditions could occur and result in sill formation. Previous models of the stresses resulting from ice shell thickening on Europa indicated that fractures can initiate within the shell and propagate both upward toward the surface and downward to the ice-ocean interface. For an ~10 km thick ice shell, we determined that flow velocities for ocean water driven up a vertical fracture by the release of lithostatic pressures are adequate for reaching the subsurface before freezing occurs (LPSC #3033). We propose the next step for sill emplacement could occur through horizontal fracturing. Nominally, the stress field in a material under lithostatic load is conducive to vertical crack propagation. However, factors exist that can cause the stress field to change and propagate cracks horizontally. Seismically imaged terrestrial sills beneath mid-ocean ridges often occur in areas with extensive cracking and/or faulting, suggesting crack interactions may play a key role. Through application of a finite element program, we modeled four stress changing mechanisms and the resulting fracture propagation in a 10 km thick ice shell on Europa: (1) mechanical layering, (2) shallow cracks to the surface, (3) deep cracks from the ocean-ice interface and (4) shallow and deep cracks combined. Results determined that all mechanisms cause some turn in propagation direction, with Model 4 (both shallow and deep cracks) enabling the greatest turn to ~ horizontal. The horizontal extent of the fracture

  11. Liquid-liquid and liquid-solid equilibria of systems containing water and selected chlorophenols

    SciTech Connect

    Jaoui, M.; Luszczyk, M.; Rogalski, M.

    1999-12-01

    Chlorinated phenols are present in effluents of oil refinery, coal mining, plastic, leather, paint, and pharmaceutical industrial plants. The solubilities of phenol, 4-chlorophenol, 2,4-dichlorophenol, 2,4,6-trichlorophenol, and pentachlorophenol in water were determined in the temperature range between 270 K and 423 K. Dynamic thermal analysis and a visual static method were used to establish the phase diagrams. Results obtained over a wide temperature and concentration range were used to model the liquid-liquid coexistence curve of the systems studied.

  12. Polarized View of Supercooled Liquid Water Clouds

    NASA Technical Reports Server (NTRS)

    Alexandrov, Mikhail D.; Cairns, Brian; Van Diedenhoven, Bastiaan; Ackerman, Andrew S.; Wasilewski, Andrzej P.; McGill, Matthew J.; Yorks, John E.; Hlavka, Dennis L.; Platnick, Steven E.; Arnold, G. Thomas

    2016-01-01

    Supercooled liquid water (SLW) clouds, where liquid droplets exist at temperatures below 0 C present a well known aviation hazard through aircraft icing, in which SLW accretes on the airframe. SLW clouds are common over the Southern Ocean, and climate-induced changes in their occurrence is thought to constitute a strong cloud feedback on global climate. The two recent NASA field campaigns POlarimeter Definition EXperiment (PODEX, based in Palmdale, California, January-February 2013) and Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS, based in Houston, Texas in August- September 2013) provided a unique opportunity to observe SLW clouds from the high-altitude airborne platform of NASA's ER-2 aircraft. We present an analysis of measurements made by the Research Scanning Polarimeter (RSP) during these experiments accompanied by correlative retrievals from other sensors. The RSP measures both polarized and total reflectance in 9 spectral channels with wavelengths ranging from 410 to 2250 nm. It is a scanning sensor taking samples at 0.8deg intervals within 60deg from nadir in both forward and backward directions. This unique angular resolution allows for characterization of liquid water droplet size using the rainbow structure observed in the polarized reflectances in the scattering angle range between 135deg and 165deg. Simple parametric fitting algorithms applied to the polarized reflectance provide retrievals of the droplet effective radius and variance assuming a prescribed size distribution shape (gamma distribution). In addition to this, we use a non-parametric method, Rainbow Fourier Transform (RFT),which allows retrieval of the droplet size distribution without assuming a size distribution shape. We present an overview of the RSP campaign datasets available from the NASA GISS website, as well as two detailed examples of the retrievals. In these case studies we focus on cloud fields with spatial features

  13. Liquid penetration inside glass nozzle during bubble departures in water

    NASA Astrophysics Data System (ADS)

    Dzienis, P.; Mosdorf, R.; Augustyniak, J.

    2016-09-01

    Liquid penetration into the glass nozzle with inner diameter of 1 mm during the bubble, departures in distilled (surface tension = 65 mN/m) and not distilled (surface tension = 72 mN/m), water was investigated. It has been shown that dynamics of liquid movement inside the nozzle depend on the water surface tension. Maximum value of liquid penetration inside the nozzle is different for distilled and not distilled water. In not distilled water the depth of liquid penetration into the nozzle depends on air volume flow rate. For desilted water this value is constant.

  14. Ab Initio Quantum Simulations of Liquid Water

    NASA Astrophysics Data System (ADS)

    Gergely, John; Ceperley, David; Gygi, Francois

    2007-03-01

    Some recent efforts at simulating liquid water have employed ``ab initio'' molecular dynamics (AIMD) methods with forces from a version of density functional theory (DFT) and, in some cases, imaginary-time path integrals (PI) to study quantum effects of the protons. Although AIMD methods have met with many successes, errors introduced by the approximations and choices of simulation parameters are not fully understood. We report on path integral Monte Carlo (PIMC) studies of liquid water using DFT energies that provide quantitative benchmarks for PI-AIMD work. Specifically, we present convergence studies of the path integrals and address whether the Trotter number can be reduced by improving the form of the (approximate) action. Also, we assess 1) whether typical AIMD simulations are sufficiently converged in simulation time, i.e., if there is reason to suspect that nonergodic behavior in PI-AIMD methods leads to poor convergence, and 2) the relative efficiency of the methods. E. Schwegler, J.C. Grossman, F. Gygi, G. Galli, J. Chem. Phys 121, 5400 (2004).

  15. Alteration of an annealed and irradiated lunar fines sample by adsorbed water

    NASA Technical Reports Server (NTRS)

    Holmes, H. F.; Agron, P. A.; Eichler, E.; Fuller, E. L., Jr.; Okelley, G. D.; Gammage, R. B.

    1975-01-01

    Apollo 12 lunar fines sample 12070,403 was annealed at 1000 C and subsequently irradiated with a beam of 130 MeV Fe(9+) ions. Adsorptions of nitrogen and water were measured before and after the irradiation. Prior to the irradiation, the fines were nonporous and water had no effect on the physical characteristics of the lunar fines. In contrast, after the irradiation, the interaction with water caused an increase in the specific surface area and created a pore system. These results are definitive evidence that the interaction of water with damage tracks is the prime factor involved in the alteration of lunar fines by adsorbed water.

  16. Effects of Atmospheric Air Plasma Irradiation on pH of Water

    NASA Astrophysics Data System (ADS)

    Sarinont, Thapanut; Koga, Kazunori; Kitazaki, Satoshi; Uchida, Giichirou; Hayashi, Nobuya; Shiratani, Masaharu

    We have studied the effects of atmospheric air plasma irradiation to water using a scalable dielectric barrier discharge device. Measurements of the pH of water treated by the plasmas have shown the pH decreases due to peroxide molecules generated by plasma irradiation and depends on material of water container. We also found this plasma treated water has little effect on the growth enhancement on Radish sprouts compare with plasma irradiation on dry seeds and the plasma irradiation can affect them through the water buffer of 0.2 mm in thickness.

  17. Sublimation and Irradiation of Glycolaldehyde/Water Ices

    NASA Astrophysics Data System (ADS)

    Burke, Daren; Brown, W. A.; Viti, S.; Woods, P. M.; Slater, B.

    2012-05-01

    There is currently great interest among astronomers and astrobiologists in the inventory of organic molecules in space, in particular in star and planet-forming regions. Observations towards the Galactic Centre have revealed a rich and complex chemistry, from simple organic molecules such as methane (CH4) and methanol (CH3OH) to the recent detection of ethyl formate (C2H5OCHO) and n-propyl cyanide (C3H7CN). Amongst the most important organic species detected in space is glycolaldehyde (CH2OHCHO), an isomer of methyl formate (HCOOCH3) and acetic acid (CH3COOH). Glycolaldehyde is the simplest of the monosaccharide sugars and it reacts with propenal to form ribose, a central constituent of RNA. As a consequence, it is thought that glycolaldehyde may have a role in the origins of life in our universe. We present a detailed investigation of the adsorption and desorption of glycolaldehyde and methyl formate using temperature programmed desorption (TPD) and reflection absorption infrared spectroscopy (RAIRS) under ultra-high vacuum. The sublimation of glycolaldehyde/water and methyl formate/water containing ices from a model carbonaceous grain surface (graphite) will be presented, along with kinetic parameters for desorption (such as the binding energy, order of desorption and desorption pre-exponential factor) derived from analysis of TPD. These experimental parameters will be incorporated into astronomical models of star-forming regions. Additional experiments investigating the stability of glycolaldehyde/water containing ices to electron/UV irradiation will also be discussed. Electron irradiation (simulating the effect of cosmic ray ionisation, which produces electrons) and UV irradiation (over a range of wavelengths) is used to examine competing routes for non-thermal desorption, decomposition and formation. RAIRS and TPD will be used to identify any reaction products and to monitor the desorption/decomposition of glycolaldehyde as a function of irradiation time. This

  18. Ice Electric: Electron Irradiation Experiments with Porous Water Ice Samples

    NASA Astrophysics Data System (ADS)

    Galli, A.; Vorburger, A.; Wurz, P.; Pommerol, A.; Poch, O.; Jost, B.; Brouet, Y.

    2016-12-01

    The importance of energetic ions impacting the surface of the icy moons of Jupiter for surface weathering and for atmospheric release processes has been studied to some extent in models and in laboratory experiments. The tenuous oxygen atmosphere at Europa, e.g., is believed to be the result of O+ and S+ magnetosphericions sputtering water ice. By comparison, the role of magnetospheric electrons irradiating icy surfaces has attracted little attention. To better understand the effects of the plasma environment on icy surfaces in the outer solar system, we prepared centimeter-sized samples of porous water ice and irradiated them with fast electrons (1-10 keV energy) at pressures and temperatures relevant for the large icy moons of Jupiter. One of the known effects is that electron irradiation triggers chemical reactions in the ice (so-called radiolysis), leading to the formation of H2, O2, and other products. We present new results on the release efficiencies of such radiolysis products from a porous ice layer. We also estimate the sputtering yields for electrons ejecting electrons or molecules and we study the thermal and electric effects of weak and strong electron beams on ice samples. Finally, we examine the relevance of these experimental results for surface processes on the icy moons of Jupiter, considering the few observational constraints on the plasma environment and surface properties. Figure: Ice sample at the end of an experiment. The more energetic electron beams heated up the ice to temperatures where sublimation sets in and forms troughs.

  19. Near-IR irradiation of the S2 state of the water oxidizing complex of photosystem II at liquid helium temperatures produces the metalloradical intermediate attributed to S1Y(Z*).

    PubMed

    Koulougliotis, Dionysios; Shen, Jian-Ren; Ioannidis, Nikolaos; Petrouleas, Vasili

    2003-03-18

    Near-IR (NIR) excitation at liquid He temperatures of photosystem II (PSII) membranes from the cyanobacterium Synechococcus vulcanus or from spinach poised in the S2 state results in the production of a g = 2.035 EPR resonance, reminiscent of metalloradical signals. The signal is smaller in the spinach preparations, but it is significantly enhanced by the addition of exogenous quinones. Ethanol (2-3%, v/v) eliminates the ability to trap the signal. The g = 2.035 signal is identical to the one recently obtained by Nugent et al. by visible-light illumination of the S1 state, and preferably assigned to S1Y(Z*) [Nugent, J. H. A., Muhiuddin, I. P., and Evans, M. C. W. (2002) Biochemistry 41, 4117-4126]. The production of the g = 2.035 signal by liquid He temperature NIR excitation of the S2 state is paralleled by a significant reduction (typically 40-45% in S. vulcanus) of the S2 state multiline signal. This is in part due to the conversion of the Mn cluster to higher spin states, an effect documented by Boussac et al. [Boussac, A., Un, S., Horner, O., and Rutherford, A. W. (1998) Biochemistry 37, 4001-4007], and in part due to the conversion to the g = 2.035 configuration. Following the decay of the g = 2.035 signal at liquid helium temperatures (decay halftimes in the time range of a few to tens of minutes depending on the preparation), annealing at elevated temperatures (-80 degrees C) results in only partial restoration of the S2 state multiline signal. The full size of the signal can be restored by visible-light illumination at -80 degrees C, implying that during the near-IR excitation and subsequent storage at liquid helium temperatures recombination with Q(A-) (and therefore decay of the S2 state to the S1 state) occurred in a fraction of centers. In support of this conclusion, the g = 2.035 signal remains stable for several hours (at 11 K) in centers poised in the S2...Q(A) configuration before the NIR excitation. The extended stability of the signal under these

  20. The Liquid Treasure Water History Trunk: Learning from the Past.

    ERIC Educational Resources Information Center

    Kesselheim, Alan S.; And Others

    This document is a guide to building a Liquid Treasure Water History Trunk that allows educators and students of all ages to learn about water from a historical perspective. By assembling historical water related items into a meaningful and interesting learning format--The Liquid Treasure Trunk--teachers and students of all ages can gain a glimpse…

  1. The Liquid Treasure Water History Trunk: Learning from the Past.

    ERIC Educational Resources Information Center

    Kesselheim, Alan S.; And Others

    This document is a guide to building a Liquid Treasure Water History Trunk that allows educators and students of all ages to learn about water from a historical perspective. By assembling historical water related items into a meaningful and interesting learning format--The Liquid Treasure Trunk--teachers and students of all ages can gain a glimpse…

  2. Evidence for Recent Liquid Water on Mars

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Newton Crater is a large basin formed by an asteroid impact that probably occurred more than 3 billion years ago. It is approximately 287 kilometers (178 miles) across. The picture shown here (top) highlights the north wall of a specific, smaller crater located in the southwestern quarter of Newton Crater (above). The crater of interest was also formed by an impact; it is about 7 km (4.4 mi) across, which is about 7 times bigger than the famous Meteor Crater in northern Arizona in North America. The north wall of the small crater has many narrow gullies eroded into it. These are hypothesized to have been formed by flowing water and debris flows. Debris transported with the water created lobed and finger-like deposits at the base of the crater wall where it intersects the floor (bottom center top image). Many of the finger-like deposits have small channels indicating that a liquid, most likely water, flowed in these areas. Hundreds of individual water and debris flow events might have occurred to create the scene shown here. Each outburst of water from higher up on the crater slopes would have constituted a competition between evaporation, freezing, and gravity. The individual deposits at the ends of channels in this MOC image mosaic were used to get a rough estimate of the minimum amount of water that might be involved in each flow event. This is done first by assuming that the deposits are like debris flows on Earth. In a debris flow, no less than about 10% (and no more than 30%) of their volume is water. Second, the volume of an apron deposit is estimated by measuring the area covered in the MOC image and multiplying it by a conservative estimate of thickness, 2 meters (6.5 feet). For a flow containing only 10% water, these estimates conservatively suggest that about 2.5 million liters (660,000 gallons) of water are involved in each event; this is enough to fill about 7 community-sized swimming pools or enough to supply 20 people with their water needs for a year

  3. Water splitting on semiconductor catalysts under visible-light irradiation.

    PubMed

    Navarro Yerga, Rufino M; Alvarez Galván, M Consuelo; del Valle, F; Villoria de la Mano, José A; Fierro, José L G

    2009-01-01

    Sustainable hydrogen production is a key target for the development of alternative, future energy systems that will provide a clean and affordable energy supply. The Sun is a source of silent and precious energy that is distributed fairly all over the Earth daily. However, its tremendous potential as a clean, safe, and economical energy source cannot be exploited unless the energy is accumulated or converted into more useful forms. The conversion of solar energy into hydrogen via the water-splitting process, assisted by photo-semiconductor catalysts, is one of the most promising technologies for the future because large quantities of hydrogen can potentially be generated in a clean and sustainable manner. This Minireview provides an overview of the principles, approaches, and research progress on solar hydrogen production via the water-splitting reaction on photo-semiconductor catalysts. It presents a survey of the advances made over the last decades in the development of catalysts for photochemical water splitting under visible-light irradiation. The Minireview also analyzes the energy requirements and main factors that determine the activity of photocatalysts in the conversion of water into hydrogen and oxygen using sunlight. Remarkable progress has been made since the pioneering work by Fujishima and Honda in 1972, but he development of photocatalysts with improved efficiencies for hydrogen production from water using solar energy still faces major challenges. Research strategies and approaches adopted in the search for active and efficient photocatalysts, for example through new materials and synthesis methods, are presented and analyzed.

  4. Discharge characteristics in liquid helium, liquid nitrogen and pure water preparatory to fabrication of carbon nanomaterials

    NASA Astrophysics Data System (ADS)

    Kawasaki, Hiroharu; Shigematsu, Toshinobu; Imasaka, Kiminobu; Ohshima, Tamiko; Yagyu, Yoshihito; Suda, Yoshiaki

    2012-12-01

    Discharge characteristics and emission spectra of the discharges in low-temperature liquid such as liquid helium have been measured to investigate the conditions for fabrication of carbon nanomaterial by arc discharge in low-temperature liquid. Measurements of the discharge characteristics of the resulting plasma and observation of the associated optical emission spectra show that the behaviour of discharge current over time and the associated spectra depend strongly on discharge voltage and both may be related to the temperature of the carbon target. However, discharge voltage and current with time are almost the same regardless of whether the liquid is pure water, liquid nitrogen, liquid helium and superfluid liquid helium

  5. Liquid-liquid transition without macroscopic phase separation in a water-glycerol mixture

    NASA Astrophysics Data System (ADS)

    Murata, Ken-Ichiro; Tanaka, Hajime

    2012-05-01

    The existence of more than two liquid states in a single-component substance and the ensuing liquid-liquid transitions (LLTs) has attracted considerable attention because of its counterintuitive nature and its importance in the fundamental understanding of the liquid state. Here we report direct experimental evidence for a genuine (isocompositional) LLT without macroscopic phase separation in an aqueous solution of glycerol. We show that liquid I transforms into liquid II by way of two types of kinetics: nucleation and growth, and spinodal decomposition. Although liquid II is metastable against crystallization, we could access both its static and dynamical properties experimentally. We find that liquids I and II differ in density, refractive index, structure, hydrogen bonding state, glass transition temperature and fragility, and that the transition between the two liquids is mainly driven by the local structuring of water rather than of glycerol, suggesting a link to a plausible LLT inpure water.

  6. Mass Spectrometry of Liquid Aniline Aerosol Particles by IR/UV Laser Irradiation.

    PubMed

    Zelenyuk, A; Cabalo, J; Baer, T; Miller, R E

    1999-05-01

    The first results are reported from a new single-particle two-color laser time-of-flight mass spectrometer, incorporating a combination of infrared (CO(2)) and UV (excimer) laser irradiation. This combination of lasers has the capability to effectively separate the desorption or evaporation step from the ionization step, thereby greatly improving the analytical capabilities of such an instrument. The results on liquid aerosols, such as aniline, show that prior evaporation of the aerosol particle with the IR laser increases the ion signal produced by the excimer laser by more than 2 orders of magnitude. In the case of nitrobenzene aerosols, the excimer laser alone produces no ions, while a very large signal is observed when the aerosol is first irradiated with the CO(2) laser. A simple model, based on the Coulomb explosion of the ionized aerosol, is used to estimate the number of ions generated by the excimer laser (∼10(5) ions). Experimental evidence based on the observed time delay of protonated aniline parent ions indicates that the laser irradiation of the liquid aerosol results in a stable neutral plasma which separates into positive and negative charges only after a 100-500-ns delay.

  7. Organics Produced by Irradiation of Frozen and Liquid HCN Solutions: Implications for Chemical Evolution Studies

    NASA Astrophysics Data System (ADS)

    Colín-García, M.; Negrón-Mendoza, A.; Ramos-Bernal, S.

    2009-04-01

    Hydrogen cyanide (HCN), an important precursor of organic compounds, is widely present in extraterrestrial environments. HCN is also readily synthesized in prebiotic simulation experiments. To gain insight into the radiation chemistry of one of the most important and highly versatile constituents of cometary ices, we examined the behavior of over-irradiated frozen and liquid HCN solutions under ionizing radiation. The samples were exposed to gamma radiation at a dose range from 0 up to 419 kGy. Ultraviolet spectroscopy and gas chromatography were used to follow the process. The analyses confirmed that gamma-ray irradiation of liquid HCN solutions generates several organic products. Many of them are essential to life; we verified the presence of carboxylic acids (some of them members of the Krebs cycle) as well as free amino acids and urea. These are the first studies to reveal the presence of these compounds in experiments performed at low temperatures and bulk irradiation. Organic material was produced even at low temperatures and low radiation doses. This work strongly supports the presumption that, as a parent molecule, HCN played a central essential role in the process of chemical evolution on early Earth, comets, and other extraterrestrial environments.

  8. Air and water stable ionic liquids in physical chemistry.

    PubMed

    Endres, Frank; Zein El Abedin, Sherif

    2006-05-14

    Ionic liquids are defined today as liquids which solely consist of cations and anions and which by definition must have a melting point of 100 degrees C or below. Originating from electrochemistry in AlCl(3) based liquids an enormous progress was made during the recent 10 years to synthesize ionic liquids that can be handled under ambient conditions, and today about 300 ionic liquids are already commercially available. Whereas the main interest is still focussed on organic and technical chemistry, various aspects of physical chemistry in ionic liquids are discussed now in literature. In this review article we give a short overview on physicochemical aspects of ionic liquids, such as physical properties of ionic liquids, nanoparticles, nanotubes, batteries, spectroscopy, thermodynamics and catalysis of/in ionic liquids. The focus is set on air and water stable ionic liquids as they will presumably dominate various fields of chemistry in future.

  9. Temporal Evolution of the High-energy Irradiation and Water Content of TRAPPIST-1 Exoplanets

    NASA Astrophysics Data System (ADS)

    Bourrier, V.; de Wit, J.; Bolmont, E.; Stamenković, V.; Wheatley, P. J.; Burgasser, A. J.; Delrez, L.; Demory, B.-O.; Ehrenreich, D.; Gillon, M.; Jehin, E.; Leconte, J.; Lederer, S. M.; Lewis, N.; Triaud, A. H. M. J.; Van Grootel, V.

    2017-09-01

    The ultracool dwarf star TRAPPIST-1 hosts seven Earth-size transiting planets, some of which could harbor liquid water on their surfaces. Ultraviolet observations are essential to measuring their high-energy irradiation and searching for photodissociated water escaping from their putative atmospheres. Our new observations of the TRAPPIST-1 Lyα line during the transit of TRAPPIST-1c show an evolution of the star emission over three months, preventing us from assessing the presence of an extended hydrogen exosphere. Based on the current knowledge of the stellar irradiation, we investigated the likely history of water loss in the system. Planets b to d might still be in a runaway phase, and planets within the orbit of TRAPPIST-1g could have lost more than 20 Earth oceans after 8 Gyr of hydrodynamic escape. However, TRAPPIST-1e to h might have lost less than three Earth oceans if hydrodynamic escape stopped once they entered the habitable zone (HZ). We caution that these estimates remain limited by the large uncertainty on the planet masses. They likely represent upper limits on the actual water loss because our assumptions maximize the X-rays to ultraviolet-driven escape, while photodissociation in the upper atmospheres should be the limiting process. Late-stage outgassing could also have contributed significant amounts of water for the outer, more massive planets after they entered the HZ. While our results suggest that the outer planets are the best candidates to search for water with the JWST, they also highlight the need for theoretical studies and complementary observations in all wavelength domains to determine the nature of the TRAPPIST-1 planets and their potential habitability.

  10. Elimination of diclofenac from water using irradiation technology.

    PubMed

    Homlok, Renáta; Takács, Erzsébet; Wojnárovits, László

    2011-10-01

    The effluents of wastewater treatment plants, usually directly emitted to the environment, often contain the anti-inflammatory drug diclofenac (DCF). The paper investigates DCF elimination using irradiation technology. Hydroxyl radical and hydrated electron reactive intermediates resulting from water radiolysis effectively degrade DCF and strongly reduce the toxicity of the solutions. ()OH attaches to one of the rings of DCF, and hydroxylated molecules, 2,6-dichloroaniline and quinoid type compounds are the products. Hydrated electron adds to the chlorine atom containing ring, in the reaction quinoid type compounds and 4-chloroacridine form. At a 0.1 mM DCF concentration, a ∼1 kGy absorbed dose is needed for the degradation of DCF molecules, but for mineralization of the products (in presence of O2) an order of magnitude higher dose is required. For irradiation of wastewater after biological treatment a ∼1 kGy dose is suggested. At this dose DCF and other drugs or metabolites present at μg L(-1) level are eliminated together with microorganism deactivation. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Enhanced mass transfer during solid liquid extraction of gamma-irradiated red beetroot

    NASA Astrophysics Data System (ADS)

    Nayak, Chetan A.; Chethana, S.; Rastogi, N. K.; Raghavarao, K. S. M. S.

    2006-01-01

    The exposure to gamma-irradiation pretreatment increases cell wall permeabilization, resulting in loss of turgor pressure, which led to the increase of extractability of betanin from red beetroot. The degree of extraction of betanin was investigated using gamma irradiation as a pretreatment prior to the solid-liquid extraction process and compared with control beetroot samples. The beetroot subjected to different doses of gamma irradiation (2.5, 5.0, 7.5, 10.0 kGy) and control was dipped in an acetic acid medium (1% v/v) to extract the betanin. The diffusion coefficients for betanin as well as ionic component were estimated considering Fickian diffusion. The results indicated an increase in the diffusion coefficient of betanin (0.302×10 -9-0.463×10 -9 m 2/s) and ionic component (0.248×10 -9-0.453×10 -9 m 2/s) as the dose rate increased (from 2.5 to 10.0 kGy). The degradation constant was found to increase (0.050-0.079 min -1) with an increase gamma-irradiation doses (2.5-10.0 kGy), indicating lower stability of the betanin as compared to control sample at 65 °C.

  12. Effect of ion beam irradiation and rubbing on the directional behavior and alignment mechanism of liquid crystals on polyimide surfaces

    SciTech Connect

    Lee, Kang-Min; Oh, Byeong-Yun; Kim, Young-Hwan; Seo, Dae-Shik

    2009-01-01

    We investigated the effects of ion beam (IB) irradiation and rubbing on the directional behavior and alignment mechanism of liquid crystals (LCs) on polyimide (PI) surfaces. We found that the LC direction follows the IB irradiation alignment direction on the PI surface regardless of whether the irradiation occurs before or after rubbing. We assumed that the LC direction depends strongly on the C-O bonds created from C=O bonds on the PI surface broken by IB irradiation and conducted an investigation of the chemical bonding state of the PI surface by x-ray photoelectron spectroscopy.

  13. Ionic liquid-based microwave-assisted dispersive liquid-liquid microextraction and derivatization of sulfonamides in river water, honey, milk, and animal plasma.

    PubMed

    Xu, Xu; Su, Rui; Zhao, Xin; Liu, Zhuang; Zhang, Yupu; Li, Dan; Li, Xueyuan; Zhang, Hanqi; Wang, Ziming

    2011-11-30

    The ionic liquid-based microwave-assisted dispersive liquid-liquid microextraction (IL-based MADLLME) and derivatization was applied for the pretreatment of six sulfonamides (SAs) prior to the determination by high-performance liquid chromatography (HPLC). By adding methanol (disperser), fluorescamine solution (derivatization reagent) and ionic liquid (extraction solvent) into sample, extraction, derivatization, and preconcentration were continuously performed. Several experimental parameters, such as the type and volume of extraction solvent, the type and volume of disperser, amount of derivatization reagent, microwave power, microwave irradiation time, pH of sample solution, and ionic strength were investigated and optimized. When the microwave power was 240 W, the analytes could be derivatized and extracted simultaneously within 90 s. The proposed method was applied to the analysis of river water, honey, milk, and pig plasma samples, and the recoveries of analytes obtained were in the range of 95.0-110.8, 95.4-106.3, 95.0-108.3, and 95.7-107.7, respectively. The relative standard deviations varied between 1.5% and 7.3% (n=5). The results showed that the proposed method was a rapid, convenient and feasible method for the determination of SAs in liquid samples.

  14. Modification on liquid retention property of cassava starch by radiation grafting with acrylonitrile. I. Effect of γ-irradiation on grafting parameters

    NASA Astrophysics Data System (ADS)

    Kiatkamjornwong, S.; Chvajarernpun, J.; Nakason, C.

    1993-07-01

    Radiation modification on liquid retention properties of native cassava starch, gelatinized at 85°C, by graft copolymerization with acrylonitrile was carried out by mutual irradiation to gamma-rays. A thin aluminum foil was used to cover the inner wall of the reaction vessel, so that the homopolymer concentration was reduced to be less than 1.0% with a distilled water retention value of 665 g/g of the dry weight of the saponified grafted product. Confirmation of graft copolymerization and saponification reactions was made by the infrared spectrophotometric technique. The combined effect of radiation parameters in terms of an irradiation time and a dose rate to the total dose on the extent of the grafting reaction expressed in terms of grafting parameters which directly influenced liquid retention values was evaluated in conjunction with statistical analysis.

  15. Interactions between water and 1-butyl-1-methylpyrrolidinium ionic liquids

    SciTech Connect

    Fadeeva, Tatiana A.; DeVine, Jessalyn A.; Castner, Edward W.; Husson, Pascale; Costa Gomes, Margarida F.; Greenbaum, Steven G.

    2015-08-14

    We report experimental results on the diffusivity of water in two ionic liquids obtained using the pulsed-gradient spin-echo NMR method. Both ionic liquids have the same cation, 1-butyl-1-methylpyrrolidinium, but different trifluoromethyl-containing anions. One has a strongly hydrophobic anion, bis(trifluoromethylsulfonyl)amide, while the second has a hydrophilic anion, trifluoromethylsulfonate. Transport of water in these ionic liquids is much faster than would be predicted from hydrodynamic laws, indicating that the neutral water molecules experience a very different friction than the anions and cations at the molecular level. Temperature-dependent viscosities, conductivities, and densities are reported as a function of water concentration to further analyze the properties of the ionic liquid-water mixtures. These results on the properties of water in ionic liquids should be of interest to researchers in diverse areas ranging from separations, solubilizing biomass and energy technologies.

  16. Interactions between water and 1-butyl-1-methylpyrrolidinium ionic liquids

    NASA Astrophysics Data System (ADS)

    Fadeeva, Tatiana A.; Husson, Pascale; DeVine, Jessalyn A.; Costa Gomes, Margarida F.; Greenbaum, Steven G.; Castner, Edward W.

    2015-08-01

    We report experimental results on the diffusivity of water in two ionic liquids obtained using the pulsed-gradient spin-echo NMR method. Both ionic liquids have the same cation, 1-butyl-1-methylpyrrolidinium, but different trifluoromethyl-containing anions. One has a strongly hydrophobic anion, bis(trifluoromethylsulfonyl)amide, while the second has a hydrophilic anion, trifluoromethylsulfonate. Transport of water in these ionic liquids is much faster than would be predicted from hydrodynamic laws, indicating that the neutral water molecules experience a very different friction than the anions and cations at the molecular level. Temperature-dependent viscosities, conductivities, and densities are reported as a function of water concentration to further analyze the properties of the ionic liquid-water mixtures. These results on the properties of water in ionic liquids should be of interest to researchers in diverse areas ranging from separations, solubilizing biomass and energy technologies.

  17. Interactions between water and 1-butyl-1-methylpyrrolidinium ionic liquids.

    PubMed

    Fadeeva, Tatiana A; Husson, Pascale; DeVine, Jessalyn A; Costa Gomes, Margarida F; Greenbaum, Steven G; Castner, Edward W

    2015-08-14

    We report experimental results on the diffusivity of water in two ionic liquids obtained using the pulsed-gradient spin-echo NMR method. Both ionic liquids have the same cation, 1-butyl-1-methylpyrrolidinium, but different trifluoromethyl-containing anions. One has a strongly hydrophobic anion, bis(trifluoromethylsulfonyl)amide, while the second has a hydrophilic anion, trifluoromethylsulfonate. Transport of water in these ionic liquids is much faster than would be predicted from hydrodynamic laws, indicating that the neutral water molecules experience a very different friction than the anions and cations at the molecular level. Temperature-dependent viscosities, conductivities, and densities are reported as a function of water concentration to further analyze the properties of the ionic liquid-water mixtures. These results on the properties of water in ionic liquids should be of interest to researchers in diverse areas ranging from separations, solubilizing biomass and energy technologies.

  18. Fluorescence-based remote irradiation sensor in liquid-filled hollow-core photonic crystal fiber

    SciTech Connect

    Zeltner, R.; Russell, P. St.J.; Bykov, D. S.; Xie, S.; Euser, T. G.

    2016-06-06

    We report an irradiation sensor based on a fluorescent “flying particle” that is optically trapped and propelled inside the core of a water-filled hollow-core photonic crystal fiber. When the moving particle passes through an irradiated region, its emitted fluorescence is captured by guided modes of the fiber core and so can be monitored using a filtered photodiode placed at the fiber end. The particle speed and position can be precisely monitored using in-fiber Doppler velocimetry, allowing the irradiation profile to be measured to a spatial resolution of ∼10 μm. The spectral response can be readily adjusted by appropriate choice of particle material. Using dye-doped polystyrene particles, we demonstrate detection of green (532 nm) and ultraviolet (340 nm) light.

  19. Fluorescence-based remote irradiation sensor in liquid-filled hollow-core photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Zeltner, R.; Bykov, D. S.; Xie, S.; Euser, T. G.; Russell, P. St. J.

    2016-06-01

    We report an irradiation sensor based on a fluorescent "flying particle" that is optically trapped and propelled inside the core of a water-filled hollow-core photonic crystal fiber. When the moving particle passes through an irradiated region, its emitted fluorescence is captured by guided modes of the fiber core and so can be monitored using a filtered photodiode placed at the fiber end. The particle speed and position can be precisely monitored using in-fiber Doppler velocimetry, allowing the irradiation profile to be measured to a spatial resolution of ˜10 μm. The spectral response can be readily adjusted by appropriate choice of particle material. Using dye-doped polystyrene particles, we demonstrate detection of green (532 nm) and ultraviolet (340 nm) light.

  20. Compositional investigation of liquid crystal alignment on tantalum oxide via ion beam irradiation

    SciTech Connect

    Kim, Jong-Yeon; Oh, Byeong-Yun; Kim, Byoung-Yong; Kim, Young-Hwan; Han, Jin-Woo; Han, Jeong-Min; Seo, Dae-Shik

    2008-01-28

    The homogeneously aligned liquid crystal display on Ta{sub 2}O{sub 5} via ion beam (IB) irradiation was first embodied with controllability of pretilt angle depending on incident angle of the IB. As a result of x-ray photoelectron spectroscopic analysis, the intensity of Ta-O and O-Ta bondings as a function of incident angle behaved reversely with the pretilt angle and the lowest amplitude was observed at 45 deg. It revealed that the creation of pretilt angle was attributed to the irradiation of the IB by breaking Ta-O and O-Ta bonding so orientational order was generated by directional IB. Comparable electro-optical characteristics to rubbed polyimide were also achieved.

  1. Photoelectron angular distributions from liquid water: effects of electron scattering.

    PubMed

    Thürmer, Stephan; Seidel, Robert; Faubel, Manfred; Eberhardt, Wolfgang; Hemminger, John C; Bradforth, Stephen E; Winter, Bernd

    2013-10-25

    Photoelectron angular distributions (PADs) from the liquid-water surface and from bulk liquid water are reported for water oxygen-1s ionization. Although less so than for the gas phase, the measured PADs from the liquid are remarkably anisotropic, even at electron kinetic energies lower than 100 eV, when elastic scattering cross sections for the outgoing electrons with other water molecules are large. The PADs reveal that theoretical estimates of the inelastic mean free path are likely too long at low kinetic energies, and hence the electron probing depth in water, near threshold ionization, appears to be considerably smaller than so far assumed.

  2. Removal of 30 active pharmaceutical ingredients in surface water under long-term artificial UV irradiation.

    PubMed

    Blum, Kristin M; Norström, Sara H; Golovko, Oksana; Grabic, Roman; Järhult, Josef D; Koba, Olga; Söderström Lindström, Hanna

    2017-06-01

    This study investigated the i) kinetics, and ii) proportion of photolysis of 30 relatively stable active pharmaceutical ingredients (APIs) during artificial UV irradiation for 28 d in ammonium acetate buffer, filtered and unfiltered river water. Buffer was included to control removal kinetics under stable pH conditions and without particulate matter. Dark controls were used to determine removal due to other processes than photolysis and calculate the proportion of photolysis of the total removal. The removal of each API in each matrix was determined using online solid phase extraction/liquid chromatography tandem mass spectrometry (online SPE/LC-MS/MS). Most APIs transformed during the 28 d of UV irradiation and the dark controls showed that photolysis was the major removal process for the majority of the APIs studied. The half-lives ranged from 6 h (amitriptyline) in unfiltered river water to 884 h (37 d, carbamazepine) in buffer. In unfiltered river water, the proportion of APIs with short half-lives (<48 h) was much higher (29%) than in the other matrices (4%), probably due to additional organic carbon, which could have promoted indirect photolysis. Furthermore, two APIs, memantine and fluconazole, were stable in all three matrices, while alprazolam was stable in buffer and unfiltered river water and four additional APIs were stable in buffer. Considering the relatively long-term UV-exposure, this study enabled the investigation of environmentally relevant half-lives in natural waters. Many APIs showed high persistence, which is environmentally concerning and emphasizes the importance of further studies on their environmental fate and effects. Copyright © 2017 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  3. Hydrogen bonding in protic ionic liquids: reminiscent of water.

    PubMed

    Fumino, Koichi; Wulf, Alexander; Ludwig, Ralf

    2009-01-01

    Similarities and differences: Far-infrared spectra of protic ionic liquids could be assigned to intermolecular bending and stretching modes of hydrogen bonds. The characteristics of the low-frequency spectra resemble those of water. Both liquids form three-dimensional network structures, but only water is capable of building tetrahedral configurations. EAN: ethylammonium nitrate, PAN: propylammonium nitrate, DMAN: dimethylammonium nitrate.

  4. The glass-liquid transition of water on hydrophobic surfaces.

    PubMed

    Souda, Ryutaro

    2008-09-28

    Interactions of thin water films with surfaces of graphite and vitrified room-temperature ionic liquid [1-butyl-3-methylimidazolium hexafluorophosphate ([bmim][PF(6)])] were investigated using time-of-flight secondary ion mass spectrometry as a function of temperature and annealing time to elucidate the glass-liquid transition of water at the molecular level. Surface diffusion of water occurs at temperatures higher than 120 K, thereby forming three-dimensional clusters (a two-dimensional layer) on the [bmim][PF(6)] (graphite) surface. The hydrophobic effect of the surface decreases with increasing coverage of water; the bulklike properties evolve up to 40 ML, as evidenced by the occurrence of film dewetting at around the conventional glass transition temperature (140 K). Results also showed that aging is necessary for the water monolayer (a 40 ML water film) to dewet the graphite ([bmim][PF(6)]) surface. The occurrence of aging is explainable by the successive evolution of two distinct liquids during the glass-liquid transition: low density liquid is followed by supercooled liquid water. The water monolayer on graphite is characterized by the preferred orientation of unpaired OH groups toward the surface; this structure is arrested during the aging time despite the occurrence of surface diffusion. However, the water monolayer formed on the [bmim][PF(6)] surface agglomerates immediately after the commencement of surface diffusion. The structure of low density liquid tends to be arrested by the attractive interaction with the neighbors.

  5. Liquid-liquid equilibria of water + methanol + 1-octanol and water + ethanol + 1-octanol at various temperatures

    SciTech Connect

    Arce, A.; Blanco, A.; Souza, P.; Vidal, I. . Dept. of Chemical Engineering)

    1994-04-01

    This study is part of a wider program of research on the recovery of light alcohols from dilute aqueous solutions using high molecular weight solvents. The authors report liquid-liquid equilibrium data and binodal curves for the systems water + methanol + 1-octanol and water + ethanol + 1-octanol at 25, 35, and 45 C. The data were fitted to the NRTL and UNIQUAC equations.

  6. Evidence for Recent Liquid Water on Mars

    NASA Technical Reports Server (NTRS)

    2000-01-01

    This image, acquired by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) in May 2000 shows numerous examples of martian gullies that all start--or head--in a specific layer roughly a hundred meters beneath the surface of Mars. These features are located on the south-facing wall of a trough in the Gorgonum Chaos region, an area found to have many examples of gullies proposed to have formed by seepage and runoff of liquid water in recent martian times. The layer from which the gullies emanate has recessed backward to form an overhang beneath a harder layer of rock. The larger gullies have formed an alcove--an area above the overhang from which debris has collapsed to leave a dark-toned scar. Below the layer of seepage is found a dark, narrow channel that runs down the slope to an apron of debris. The small, bright, parallel features at the base of the cliff at the center-right of the picture is a series of large windblown ripples. Although the dark tone of the alcoves and channels in this image is not likely to be the result of wet ground (the contrast in this image has been enhanced), it does suggest that water has seeped out of the ground and moved down the slope quite recently. Sharp contrasts between dark and light areas are hard to maintain on Mars for very long periods of time because dust tends to coat surfaces and reduce brightness differences. To keep dust from settling on a surface, it has to have undergone some process of erosion (wind, landslides, water runoff) relatively recently. There is no way to know how recent this activity was, but educated guesses center between a few to tens of years, and it is entirely possible that the area shown in this image has water seeping out of the ground today. Centered near 37.9S, 170.2W, sunlight illuminates the MOC image from the upper left, north is toward the upper right. The context view above is from the Viking 1 orbiter and was acquired in 1977. The Viking picture is illuminated from the upper right

  7. Control of airborne and liquid-borne fungal and pet allergens using microwave irradiation.

    PubMed

    Wu, Yan; Yao, Maosheng

    2013-01-01

    In this study, the dog, cat allergens (Can f 1 and Fel d 1) and fungal allergens (Alt a 1 and Asp f 1) were aerosolized and exposed to the microwave irradiation (2450 MHz) at different output powers for up to 2 min. The allergen bioaerosols were collected by a BioSampler, and analyzed using enzyme-linked immunosorbent assay (ELISA). Control and microwave-irradiated Asp f 1 allergens were also tested with IgEs in human blood sera samples. For airborne Asp f 1 and Alt a 1 allergens, the allergenicity was shown to decrease about 50% when exposed to microwave irradiation at 385 and 119 W and relatively no change at 700 W. For airborne Can f 1 allergen, the allergenicity was shown to increase about 70% when exposed to the irradiation at 385 W, but remained relatively unchanged at 700 and 119 W. In contrast, airborne Fel d 1 allergen was observed to lose allergenicity completely at 700 W, and retained about 40% and 80% at 385 and 119 W, respectively. Radioallergosorbent (RAST) tests showed that changes detected in IgE levels in human blood sera mixtures were not statistically significant for the control and microwave-irradiated waterborne Asp f 1 allergens. This study implies that although certain allergenicity reductions were observed for some allergens in certain cases, particular care should be taken when the microwave irradiation is used to disinfect food, water, and air because of its complex effects.

  8. Irradiation performance of U-Pu-Zr metal fuels for liquid-metal-cooled reactors

    SciTech Connect

    Tsai, H.; Cohen, A.B.; Billone, M.C.; Neimark, L.A.

    1994-10-01

    This report discusses a fuel system utilizing metallic U-Pu-Zr alloys which has been developed for advanced liquid metal-cooled reactors (LMRs). Result`s from extensive irradiation testing conducted in EBR-II show a design having the following key features can achieve both high reliability and high burnup capability: a cast nominally U-20wt %Pu-10wt %Zr slug with the diameter sized to yield a fuel smear density of {approx}75% theoretical density, low-swelling tempered martensitic stainless steel cladding, sodium bond filling the initial fuel/cladding gap, and an as-built plenum/fuel volume ratio of {approx}1.5. The robust performance capability of this design stems primarily from the negligible loading on the cladding from either fuel/cladding mechanical interaction or fission-gas pressure during the irradiation. The effects of these individual design parameters, e.g., fuel smear density, zirconium content in fuel, plenum volume, and cladding types, on fuel element performance were investigated in a systematic irradiation experiment in EBR-II. The results show that, at the discharge burnup of {approx}11 at. %, variations on zirconium content or plenum volume in the ranges tested have no substantial effects on performance. Fuel smear density, on the other hand, has pronounced but countervailing effects: increased density results in greater cladding strain, but lesser cladding wastage from fuel/cladding chemical interaction.

  9. Photochemical oxidation of water and reduction of polyoxometalate anions at interfaces of water with ionic liquids or diethylether.

    PubMed

    Bernardini, Gianluca; Wedd, Anthony G; Zhao, Chuan; Bond, Alan M

    2012-07-17

    Photoreduction of [P(2)W(18)O(62)](6-), [S(2)Mo(18)O(62)](4-), and [S(2)W(18)O(62)](4-) polyoxometalate anions (POMs) and oxidation of water occurs when water-ionic liquid and water-diethylether interfaces are irradiated with white light (275-750 nm) or sunlight. The ionic liquids (ILs) employed were aprotic ([Bmim]X; Bmim = (1-butyl-3-methylimidazolium, X = BF(4), PF(6)) and protic (DEAS = diethanolamine hydrogen sulphate; DEAP = diethanolamine hydrogen phosphate). Photochemical formation of reduced POMs at both thermodynamically stable and unstable water-IL interfaces led to their initial diffusion into the aqueous phase and subsequent extraction into the IL phase. The mass transport was monitored visually by color change and by steady-state voltammetry at microelectrodes placed near the interface and in the bulk solution phases. However, no diffusion into the organic phase was observed when [P(2)W(18)O(62)](6-) was photo-reduced at the water-diethylether interface. In all cases, water acted as the electron donor to give the overall process: 4POM + 2H(2)O + hν → 4POM(-) + 4H(+) + O(2). However, more highly reduced POM species are likely to be generated as intermediates. The rate of diffusion of photo-generated POM(-) was dependent on the initial concentration of oxidized POM and the viscosity of the IL (or mixed phase system produced in cases in which the interface is thermodynamically unstable). In the water-DEAS system, the evolution of dioxygen was monitored in situ in the aqueous phase by using a Clark-type oxygen sensor. Differences in the structures of bulk and interfacial water are implicated in the activation of water. An analogous series of reactions occurred upon irradiation of solid POM salts in the presence of water vapor.

  10. Stability of liquid saline water on present day Mars

    NASA Astrophysics Data System (ADS)

    Zorzano, M.-P.; Mateo-Martí, E.; Prieto-Ballesteros, O.; Osuna, S.; Renno, N.

    2009-10-01

    Perchlorate salts (mostly magnesium and sodium perchlorate) have been detected on Mars' arctic soil by the Phoenix lander, furthermore chloride salts have been found on the Meridiani and Gusev sites and on widespread deposits on the southern Martian hemisphere. The presence of these salts on the surface is not only relevant because of their ability to lower the freezing point of water, but also because they can absorb water vapor and form a liquid solution (deliquesce). We show experimentally that small amounts of sodium perchlorate (˜ 1 mg), at Mars atmospheric conditions, spontaneously absorb moisture and melt into a liquid solution growing into ˜ 1 mm liquid spheroids at temperatures as low as 225 K. Also mixtures of water ice and sodium perchlorate melt into a liquid at this temperature. Our results indicate that salty environments make liquid water to be locally and sporadically stable on present day Mars.

  11. Spectral irradiance measurement and actinic radiometer calibration for UV water disinfection

    NASA Astrophysics Data System (ADS)

    Sperfeld, Peter; Barton, Bettina; Pape, Sven; Towara, Anna-Lena; Eggers, Jutta; Hopfenmüller, Gabriel

    2014-12-01

    In a joint project, sglux and PTB investigated and developed methods and equipment to measure the spectral and weighted irradiance of high-efficiency UV-C emitters used in water disinfection plants. A calibration facility was set up to calibrate the microbicidal irradiance responsivity of actinic radiometers with respect to the weighted spectral irradiance of specially selected low-pressure mercury and medium-pressure mercury UV lamps. To verify the calibration method and to perform on-site tests, spectral measurements were carried out directly at water disinfection plants in operation. The weighted microbicidal irradiance of the plants was calculated and compared to the measurements of various actinic radiometers.

  12. Nanoparticles alloying in liquids: Laser-ablation-generated Ag or Pd nanoparticles and laser irradiation-induced AgPd nanoparticle alloying.

    PubMed

    Semaltianos, N G; Chassagnon, R; Moutarlier, V; Blondeau-Patissier, V; Assoul, M; Monteil, G

    2017-04-18

    Laser irradiation of a mixture of single-element micro/nanomaterials may lead to their alloying and fabrication of multi-element structures. In addition to the laser induced alloying of particulates in the form of micro/nanopowders in ambient atmosphere (which forms the basis of the field of additive manufacturing technology), another interesting problem is the laser-induced alloying of a mixture of single-element nanoparticles in liquids since this process may lead to the direct fabrication of alloyed-nanoparticle colloidal solutions. In this work, bare-surface ligand-free Ag and Pd nanoparticles in solution were prepared by laser ablation of the corresponding bulk target materials, separately in water. The two solutions were mixed and the mixed solution was laser irradiated for different time durations in order to investigate the laser-induced nanoparticles alloying in liquid. Nanoparticles alloying and the formation of AgPd alloyed nanoparticles takes place with a decrease of the intensity of the surface-plasmon resonance peak of the Ag nanoparticles (at ∼405 nm) with the irradiation time while the low wavelength interband absorption peaks of either Ag or Pd nanoparticles remain unaffected by the irradiation for a time duration even as long as 30 min. The nanoalloys have lattice constants with values between those of the pure metals, which indicates that they consist of Ag and Pd in an approximately 1:1 ratio similar to the atomic composition of the starting mixed-nanoparticle solution. Formation of nanoparticle networks consisting of bimetallic alloyed nanoparticles and nanoparticles that remain as single elements (even after the end of the irradiation), joining together, are also formed. The binding energies of the 3d core electrons of both Ag and Pd nanoparticles shift to lower energies with the irradiation time, which is also a typical characteristic of AgPd alloyed nanoparticles. The mechanisms of nanoparticles alloying and network formation are also

  13. Nanoparticles alloying in liquids: Laser-ablation-generated Ag or Pd nanoparticles and laser irradiation-induced AgPd nanoparticle alloying

    NASA Astrophysics Data System (ADS)

    Semaltianos, N. G.; Chassagnon, R.; Moutarlier, V.; Blondeau-Patissier, V.; Assoul, M.; Monteil, G.

    2017-04-01

    Laser irradiation of a mixture of single-element micro/nanomaterials may lead to their alloying and fabrication of multi-element structures. In addition to the laser induced alloying of particulates in the form of micro/nanopowders in ambient atmosphere (which forms the basis of the field of additive manufacturing technology), another interesting problem is the laser-induced alloying of a mixture of single-element nanoparticles in liquids since this process may lead to the direct fabrication of alloyed-nanoparticle colloidal solutions. In this work, bare-surface ligand-free Ag and Pd nanoparticles in solution were prepared by laser ablation of the corresponding bulk target materials, separately in water. The two solutions were mixed and the mixed solution was laser irradiated for different time durations in order to investigate the laser-induced nanoparticles alloying in liquid. Nanoparticles alloying and the formation of AgPd alloyed nanoparticles takes place with a decrease of the intensity of the surface-plasmon resonance peak of the Ag nanoparticles (at ∼405 nm) with the irradiation time while the low wavelength interband absorption peaks of either Ag or Pd nanoparticles remain unaffected by the irradiation for a time duration even as long as 30 min. The nanoalloys have lattice constants with values between those of the pure metals, which indicates that they consist of Ag and Pd in an approximately 1:1 ratio similar to the atomic composition of the starting mixed-nanoparticle solution. Formation of nanoparticle networks consisting of bimetallic alloyed nanoparticles and nanoparticles that remain as single elements (even after the end of the irradiation), joining together, are also formed. The binding energies of the 3d core electrons of both Ag and Pd nanoparticles shift to lower energies with the irradiation time, which is also a typical characteristic of AgPd alloyed nanoparticles. The mechanisms of nanoparticles alloying and network formation are also

  14. Observation of broadband terahertz wave generation from liquid water

    NASA Astrophysics Data System (ADS)

    Jin, Qi; E, Yiwen; Williams, Kaia; Dai, Jianming; Zhang, X.-C.

    2017-08-01

    Bulk liquid water is a strong absorber in the terahertz (THz) frequency range, due to which liquid water has historically been sworn off as a source for THz radiation. Here, we experimentally demonstrate the generation of broadband THz waves from liquid water excited by femtosecond laser pulses. Our measurements reveal the critical dependence of the THz field upon the relative position between the water film and the focal point of the laser beam. The THz radiation from liquid water shows distinct characteristics when compared with the THz radiation from air plasmas with single color optical excitation. First, the THz field is maximized with the laser beam of longer pulse durations. In addition, the p-polarized component of the emitted THz waves will be influenced by the polarization of the optical excitation beam. It is also shown that the energy of the THz radiation is linearly dependent on the excitation pulse energy.

  15. Effect of an optically thick water layer during 9.6-μm CO2 laser irradiation on caries inhibition

    NASA Astrophysics Data System (ADS)

    Le, Charles Q.; Fried, Daniel; Sarma, Anupama V.; Featherstone, John D. B.

    2004-05-01

    Previous studies have shown that laser irradiation of dental enamel by a pulsed carbon dioxide laser can inhibit subsequent acid dissolution of the enamel surface. The aim of the present study was to determine the influence of an applied water layer before laser irradiation by a 9.6-μm TEA laser on the dissolution kinetics of the dental enamel surface. Recent studies have shown that residual non-hydroxyapatite particles accumulate on the enamel surface if a water layer is not present before laser irradiation. Such non-hydroxyapatite mineral phases are expected to profoundly influence the surface dissolution rate. Bovine enamel blocks (3x3 mm2) were irradiated at 9.6-μm wavelength with a 5-8 μs pulse duration laser and a fluence of 20 J/cm2. A motion control system and a liquid spray system were used to ensure uniform water application and uniform irradiation of the entire enamel surface. Surface acid dissolution profiles following irradiation were acquired with and without the water spray. Dissolution profiles without the water-spray manifested higher initial dissolution rates than the non-irradiated control group, followed by later rates lower than the control group. In contrast, dissolution rates with the applied water layer produced early low dissolution rates, lower than the control group, followed by a more rapid dissolution rate, similar to the control group. This study demonstrates that the application of a water layer before laser irradiation significantly alters the surface dissolution kinetics of dental enamel.

  16. Cloud top liquid water from lidar observations of marine stratocumulus

    NASA Technical Reports Server (NTRS)

    Spinhirne, J. D.; Boers, R.; Hart, W. D.

    1989-01-01

    Marine stratus clouds were simultaneously observed by nadir Nd:YAG lidar measurements and in situ cloud physics measurements. A procedure was applied to derive the two-dimensional vertical cross section of the liquid water from within the cloud top lidar observations. A comparison to direct in-cloud liquid water observations gave good results. The liquid water retrieval was limited to an effective optical depth of 1.5. The true cloud optical thickness was also obtained from the retrieval procedure to a corresponding limit of 3.8. The optical thickness of the observed marine stratus clouds was predominantly below 3.0.

  17. Observed reflectivities and liquid water content for marine stratocumulus

    NASA Technical Reports Server (NTRS)

    Coakley, J. A., Jr.; Snider, J. B.

    1989-01-01

    Simultaneous observations of cloud liquid water content and cloud reflectivity are used to verify their parametric relationship in a manner consistent with simple parameterizations often used in general-circulation climate models. The column amount of cloud liquid water was measured with a microwave radiometer on San Nicolas Island as described by Hogg et al., (1983). Cloud reflectivity was obtained through spatial coherence analysis of AVHRR imagery data as per Coakley and Baldwin (1984) and Coakley and Beckner (1988). The dependence of the observed reflectivity on the observed liquid water is discussed, and this empirical relationship is compared with the parameterization proposed by Stephens (1978).

  18. Liquid water changes its structure at 43 °C

    NASA Astrophysics Data System (ADS)

    Catalán, Javier; Gonzalo, Julio A.

    2017-07-01

    Analysis of the changes in specific (HBD acidity and HBA basicity) and general nonspecific (polarizability and dipolarity) solvent interactions in liquid water, as determined by means of solvatochromic probes, shows that this liquid undergoes an internal structural change with increasing temperature, connected with a small increase of its polarizability and basicity as well as a comparatively larger decrease of its dipolarity. This change in the structure of water shows up in a non-uniform change in the behavior of these solvent parameters in going to temperatures higher than 43 °C. Liquid water simultaneously decreases its acidity with the rise of temperature.

  19. Luminescence imaging of water during carbon-ion irradiation for range estimation.

    PubMed

    Yamamoto, Seiichi; Komori, Masataka; Akagi, Takashi; Yamashita, Tomohiro; Koyama, Shuji; Morishita, Yuki; Sekihara, Eri; Toshito, Toshiyuki

    2016-05-01

    The authors previously reported successful luminescence imaging of water during proton irradiation and its application to range estimation. However, since the feasibility of this approach for carbon-ion irradiation remained unclear, the authors conducted luminescence imaging during carbon-ion irradiation and estimated the ranges. The authors placed a pure-water phantom on the patient couch of a carbon-ion therapy system and measured the luminescence images with a high-sensitivity, cooled charge-coupled device camera during carbon-ion irradiation. The authors also carried out imaging of three types of phantoms (tap-water, an acrylic block, and a plastic scintillator) and compared their intensities and distributions with those of a phantom containing pure-water. The luminescence images of pure-water phantoms during carbon-ion irradiation showed clear Bragg peaks, and the measured carbon-ion ranges from the images were almost the same as those obtained by simulation. The image of the tap-water phantom showed almost the same distribution as that of the pure-water phantom. The acrylic block phantom's luminescence image produced seven times higher luminescence and had a 13% shorter range than that of the water phantoms; the range with the acrylic phantom generally matched the calculated value. The plastic scintillator showed ∼15 000 times higher light than that of water. Luminescence imaging during carbon-ion irradiation of water is not only possible but also a promising method for range estimation in carbon-ion therapy.

  20. Thermoluminescence dosimetry measurements of brachytherapy sources in liquid water

    SciTech Connect

    Tailor, Ramesh; Tolani, Naresh; Ibbott, Geoffrey S.

    2008-09-15

    Radiation therapy dose measurements are customarily performed in liquid water. The characterization of brachytherapy sources is, however, generally based on measurements made with thermoluminescence dosimeters (TLDs), for which contact with water may lead to erroneous readings. Consequently, most dosimetry parameters reported in the literature have been based on measurements in water-equivalent plastics, such as Solid Water. These previous reports employed a correction factor to transfer the dose measurements from a plastic phantom to liquid water. The correction factor most often was based on Monte Carlo calculations. The process of measuring in a water-equivalent plastic phantom whose exact composition may be different from published specifications, then correcting the results to a water medium leads to increased uncertainty in the results. A system has been designed to enable measurements with TLDs in liquid water. This system, which includes jigs to support water-tight capsules of lithium fluoride in configurations suitable for measuring several dosimetric parameters, was used to determine the correction factor from water-equivalent plastic to water. Measurements of several {sup 125}I and {sup 131}Cs prostate brachytherapy sources in liquid water and in a Solid Water phantom demonstrated a correction factor of 1.039{+-}0.005 at 1 cm distance. These measurements are in good agreement with a published value of this correction factor for an {sup 125}I source.

  1. Glass–liquid transition of water at high pressure

    PubMed Central

    Andersson, Ove

    2011-01-01

    The knowledge of the existence of liquid water under extreme conditions and its concomitant properties are important in many fields of science. Glassy water has previously been prepared by hyperquenching micron-sized droplets of liquid water and vapor deposition on a cold substrate (ASW), and its transformation to an ultraviscous liquid form has been reported on heating. A densified amorphous solid form of water, high-density amorphous ice (HDA), has also been made by collapsing the structure of ice at pressures above 1 GPa and temperatures below approximately 140 K, but a corresponding liquid phase has not been detected. Here we report results of heat capacity Cp and thermal conductivity, in situ, measurements, which are consistent with a reversible transition from annealed HDA to ultraviscous high-density liquid water at 1 GPa and 140 K. On heating of HDA, the Cp increases abruptly by (3.4 ± 0.2) J mol-1 K-1 before crystallization starts at (153 ± 1) K. This is larger than the Cp rise at the glass to liquid transition of annealed ASW at 1 atm, which suggests the existence of liquid water under these extreme conditions. PMID:21690361

  2. Isothermal vapor-liquid equilibria for methanol + ethanol + water, methanol + water, and ethanol + water

    SciTech Connect

    Kurihara, Kiyofumi; Takeda, Kouichi; Kojima, Kazuo; Minoura, Tsuyoshi

    1995-05-01

    Isothermal vapor-liquid equilibria were measured for the ternary system methanol + ethanol + water and its constituent binary systems of methanol + water and ethanol + water at 323.15, 328.15, and 333.15 K. The apparatus that was used made it possible to control the measured temperature and total pressure by computer. The experimental binary data were correlated by the NRTL equation. The ternary system was predicted using the binary NRTL parameters with good accuracy.

  3. Liquid chromatography-electrospray ionization tandem mass spectrometric analysis of 2-alkylcyclobutanones in irradiated chicken by precolumn derivatization with hydroxylamine.

    PubMed

    Ye, Yuran; Liu, Hanxia; Horvatovich, Peter; Chan, Wan

    2013-06-19

    Food irradiation is a common preservation method that is used in many countries. The ability to identify irradiated food is important for assuring compliance with regulatory policies, such as food labeling requirements, and for informed consumer choice. There is thus a significant demand for analytical methods of high sensitivity and selectivity to identify irradiated food, especially for foods subjected to low-dose irradiation and for processed or composite foods that contain small quantities of irradiated ingredients. 2-Alkylcyclobutanones (2-ACBs) are uniquely formed during food irradiation and have been adopted by the European Committee for Standardization as signature biomarkers for the identification of irradiated foods. We now report the development of a novel assay for quantification of 2-ACBs in γ-irradiated food by liquid extraction of fat content followed by precolumn derivatization and liquid chromatography-tandem mass spectrometric (LC-MS/MS) detection. Precolumn derivatization with hydroxylamine introduced a polar functional group into the otherwise nonpolar 2-ACBs, which greatly enhanced ESI-MS response. The method was validated for extraction efficiency, precision, accuracy, and detection limit. In comparison with the current GC-MS based European official method (EN1785:2003) for 2-ACBs determination, our new LC-MS/MS method offers a more efficient sample processing protocol with reduced solvent consumption. More importantly, the combination of chemical derivatization and LC-MS/MS detection significantly enhanced the analytical sensitivity of the method, which allows confident identification of food irradiated with as little as 10 Gy. To the best of our knowledge, this is the first report of 2-ACB determination by LC-MS/MS and the first analytical method allowing confident identification of irradiated food at dosage of down to 10 Gy.

  4. Space Station Water Processor Mostly Liquid Separator (MLS)

    NASA Technical Reports Server (NTRS)

    Lanzarone, Anthony

    1995-01-01

    This report presents the results of the development testing conducted under this contract to the Space Station Water Processor (WP) Mostly Liquid Separator (MLS). The MLS units built and modified during this testing demonstrated acceptable air/water separation results in a variety of water conditions with inlet flow rates ranging from 60 - 960 LB/hr.

  5. Liquid-liquid transition in supercooled water suggested by microsecond simulations.

    PubMed

    Li, Yaping; Li, Jicun; Wang, Feng

    2013-07-23

    The putative liquid-liquid phase transition in supercooled water has been used to explain many anomalous behaviors of water. However, no direct experimental verification of such a phase transition has been accomplished, and theoretical studies from different simulations contradict each other. We investigated the putative liquid-liquid phase transition using the Water potential from Adaptive Force Matching for Ice and Liquid (WAIL). The simulation reveals a first-order phase transition in the supercooled regime with the critical point at ~207 K and 50 MPa. Normal water is high-density liquid (HDL). Low-density liquid (LDL) emerges at lower temperatures. The LDL phase has a density only slightly larger than that of the ice-Ih and shows more long-range order than HDL. However, the transformation from LDL to HDL is spontaneous across the first-order phase transition line, suggesting the LDL configuration is not poorly formed nanocrystalline ice. It has been demonstrated in the past that the WAIL potential provides reliable predictions of water properties such as melting temperature and temperature of maximum density. Compared with other simple water potentials, WAIL is not biased by fitting to experimental properties, and simulation with this potential reflects the prediction of a high-quality first-principle potential energy surface.

  6. Liquid water in the domain of cubic crystalline ice Ic

    NASA Technical Reports Server (NTRS)

    Jenniskens, P.; Banham, S. F.; Blake, D. F.; McCoustra, M. R.

    1997-01-01

    Vapor-deposited amorphous water ice when warmed above the glass transition temperature (120-140 K), is a viscous liquid which exhibits a viscosity vs temperature relationship different from that of liquid water at room temperature. New studies of thin water ice films now demonstrate that viscous liquid water persists in the temperature range 140-210 K. where it coexists with cubic crystalline ice. The liquid character of amorphous water above the glass transition is demonstrated by (1) changes in the morphology of water ice films on a nonwetting surface observed in transmission electron microscopy (TEM) at around 175 K during slow warming, (2) changes in the binding energy of water molecules measured in temperature programmed desorption (TPD) studies, and (3) changes in the shape of the 3.07 micrometers absorption band observed in grazing angle reflection-absorption infrared spectroscopy (RAIRS) during annealing at high temperature. whereby the decreased roughness of the water surface is thought to cause changes in the selection rules for the excitation of O-H stretch vibrations. Because it is present over such a wide range of temperatures, we propose that this form of liquid water is a common material in nature. where it is expected to exist in the subsurface layers of comets and on the surfaces of some planets and satellites.

  7. Liquid water in the domain of cubic crystalline ice Ic.

    PubMed

    Jenniskens, P; Banham, S F; Blake, D F; McCoustra, M R

    1997-07-22

    Vapor-deposited amorphous water ice when warmed above the glass transition temperature (120-140 K), is a viscous liquid which exhibits a viscosity vs temperature relationship different from that of liquid water at room temperature. New studies of thin water ice films now demonstrate that viscous liquid water persists in the temperature range 140-210 K. where it coexists with cubic crystalline ice. The liquid character of amorphous water above the glass transition is demonstrated by (1) changes in the morphology of water ice films on a nonwetting surface observed in transmission electron microscopy (TEM) at around 175 K during slow warming, (2) changes in the binding energy of water molecules measured in temperature programmed desorption (TPD) studies, and (3) changes in the shape of the 3.07 micrometers absorption band observed in grazing angle reflection-absorption infrared spectroscopy (RAIRS) during annealing at high temperature. whereby the decreased roughness of the water surface is thought to cause changes in the selection rules for the excitation of O-H stretch vibrations. Because it is present over such a wide range of temperatures, we propose that this form of liquid water is a common material in nature. where it is expected to exist in the subsurface layers of comets and on the surfaces of some planets and satellites.

  8. Liquid water in the domain of cubic crystalline ice Ic

    NASA Technical Reports Server (NTRS)

    Jenniskens, P.; Banham, S. F.; Blake, D. F.; McCoustra, M. R.

    1997-01-01

    Vapor-deposited amorphous water ice when warmed above the glass transition temperature (120-140 K), is a viscous liquid which exhibits a viscosity vs temperature relationship different from that of liquid water at room temperature. New studies of thin water ice films now demonstrate that viscous liquid water persists in the temperature range 140-210 K. where it coexists with cubic crystalline ice. The liquid character of amorphous water above the glass transition is demonstrated by (1) changes in the morphology of water ice films on a nonwetting surface observed in transmission electron microscopy (TEM) at around 175 K during slow warming, (2) changes in the binding energy of water molecules measured in temperature programmed desorption (TPD) studies, and (3) changes in the shape of the 3.07 micrometers absorption band observed in grazing angle reflection-absorption infrared spectroscopy (RAIRS) during annealing at high temperature. whereby the decreased roughness of the water surface is thought to cause changes in the selection rules for the excitation of O-H stretch vibrations. Because it is present over such a wide range of temperatures, we propose that this form of liquid water is a common material in nature. where it is expected to exist in the subsurface layers of comets and on the surfaces of some planets and satellites.

  9. Inelastic cross sections for electron interactions in liquid water

    SciTech Connect

    Hamm, R.N.; Ritchie, R.H.; Turner, J.E.; Wright, H.A.

    1982-01-01

    The task was to develop a set of cross sections for electron inelastic processes in liquid water suitable for use in a Monte Carlo transport calculation. Results are plotted as inverse mean free paths vs electron energy. (DLC)

  10. Entropy-driven liquid–liquid separation in supercooled water

    PubMed Central

    Holten, V.; Anisimov, M. A.

    2012-01-01

    Twenty years ago Poole et al. suggested that the anomalous properties of supercooled water may be caused by a critical point that terminates a line of liquid–liquid separation of lower-density and higher-density water. Here we present a thermodynamic model based on this hypothesis, which describes all available experimental data for supercooled water with better quality and fewer adjustable parameters than any other model. Liquid water at low temperatures is viewed as an ‘athermal solution' of two molecular structures with different entropies and densities. Alternatively to popular models for water, in which liquid–liquid separation is driven by energy, the phase separation in the athermal two-state water is driven by entropy upon increasing the pressure, while the critical temperature is defined by the ‘reaction' equilibrium constant. The model predicts the location of density maxima at the locus of a near-constant fraction of the lower-density structure. PMID:23056905

  11. Structure and dynamics of liquid water between plates

    NASA Astrophysics Data System (ADS)

    Zhu, S.-B.; Robinson, G. W.

    1991-01-01

    Using the recently developed SPC-FP water model (simple point charge model with flexible bonds and polarization) and the molecular dynamics method, we investigate the structure and properties of liquid water between two rigid plates. In one case the plates are neutral and in the other the plates are electrically charged. In both cases substantial differences from bulk state water are found, structurally and dynamically. We observe some anomalies compared with normal liquids and attribute these to the breakage of hydrogen bonds under the influence of the solid-liquid interface. Adding an external torque enhances such breakage through the attempted alignment of the water molecules. A combination of these two contributions determines the resultant dynamical behavior of water between charged plates. The information obtained from this work should be helpful in the understanding of ``hydrophobic effects'' in aqueous solutions. The behavior of water near large polar or nonpolar molecular solutes is also revealed by these studies.

  12. Continuous in situ measurements of stable isotopes in liquid water

    NASA Astrophysics Data System (ADS)

    Herbstritt, Barbara; Gralher, Benjamin; Weiler, Markus

    2012-03-01

    We developed a method to measure in situ the isotopic composition of liquid water with minimal supervision and, most important, with a temporal resolution of less than a minute. For this purpose a microporous hydrophobic membrane contactor (Membrana) was combined with an isotope laser spectrometer (Picarro). The contactor, originally designed for degassing liquids, was used with N2 as a carrier gas in order to transform a small fraction of liquid water to water vapor. The generated water vapor was then analyzed continuously by the Picarro analyzer. To prove the membrane's applicability, we determined the specific isotope fractionation factor for the phase change through the contactor's membrane across an extended temperature range (8°C-21°C) and with different waters of known isotopic compositions. This fractionation factor is needed to subsequently derive the liquid water isotope ratio from the measured water vapor isotope ratios. The system was tested with a soil column experiment, where the isotope values derived with the new method corresponded well (R2 = 0.998 for δ18O and R2 = 0.997 for δ2H) with those of liquid water samples taken simultaneously and analyzed with a conventional method (cavity ring-down spectroscopy). The new method supersedes taking liquid samples and employs only relatively cheap and readily available components. This makes it a relatively inexpensive, fast, user-friendly, and easily reproducible method. It can be applied in both the field and laboratory wherever a water vapor isotope analyzer can be run and whenever real-time isotope data of liquid water are required at high temporal resolution.

  13. Evidence for Recent Liquid Water on Mars

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Gullies eroded into the wall of a meteor impact crater in Noachis Terra. This high resolution view (top left) from the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC) shows channels and associated aprons of debris that are interpreted to have formed by groundwater seepage, surface runoff, and debris flow. The lack of small craters superimposed on the channels and apron deposits indicates that these features are geologically young. It is possible that these gullies indicate that liquid water is present within the martian subsurface today. The MOC image was acquired on September 28, 1999. The scene covers an area approximately 3 kilometers (1.9 miles) wide by 6.7 km (4.1 mi) high (note, the aspect ratio is 1.5 to 1.0). Sunlight illuminates this area from the upper left. The image is located near 54.8S, 342.5W. The context image (above) shows the location of the MOC image on the south-facing wall of an impact crater approximately 20 kilometers (12 miles) in diameter. The context picture was obtained by the Viking 1 orbiter in 1980 and is illuminated from the upper left. The large mound on the floor of the crater in the context view is a sand dune field. The Mars Orbiter Camera high resolution images are taken black-and-white (grayscale); the color seen here has been synthesized from the colors of Mars observed by the MOC wide angle cameras and by the Viking Orbiters in the late 1970s. A brief description of how the color was generated: The MOC narrow angle camera only takes grayscale (black and white) pictures. To create the color versions seen here, we have taken much lower resolution red and blue images acquired by the MOC's wide angle cameras, and by the Viking Orbiter cameras in the 1970s, synthesized a green image by averaging red and blue, and created a pallete of colors that represent the range of colors on Mars. We then use a relationship that correlates color and brightness to assign a color to each gray level. This is only a crude approximation of

  14. Zenithal alignment of liquid crystal on homeotropic polyimide film irradiated by ion beam

    PubMed Central

    2012-01-01

    We investigate the pretilt characteristics of a nematic liquid crystal [LC] in terms of ion beam exposure conditions on the homeotropic polyimide alignment layer. The pretilt angle of LCs in the case of high-energy ion beam treatment was decreased considerably almost the same to that of the homogenous alignment layer though we used homeotropic polyimide film at first. Increasing irradiating energy, we could control the pretilt from 90° to 1° with several steps. We believe that this is because the side chain with hydrophobicity in the used polyimide is broken by ion beam exposure. To confirm it, contact angle measurement was carried out. With this result, we can easily control the LC pretilt in the pixel with appropriate exposure conditions which is critical to achieve excellent electrooptic characteristics and good image quality. PMID:22221956

  15. Free ion yield observed in liquid isooctane irradiated by gamma rays. Comparison with the Onsager theory.

    PubMed

    Pardo, J; Franco, L; Gómez, F; Iglesias, A; Lobato, R; Mosquera, J; Pazos, A; Pena, J; Pombar, M; Rodríguez, A; Sendón, J

    2004-05-21

    We have analysed data on the free ion yield observed in liquid isooctane irradiated by 60Co gamma rays within the framework of the Onsager theory about initial recombination. Several distribution functions describing the electron thermalization distance have been used and compared with the experimental results: a delta function, a Gaussian-type function and an exponential function. A linear dependence between the free ion yield and the external electric field has been found at low-electric-field values (E < or = 1.2 x 10(3) V mm(-1)) in excellent agreement with the Onsager theory. At higher electric field values, we obtain a solution in power series of the external field using the Onsager theory.

  16. Flow type barrier-discharge UV photoreactor for irradiating liquids and gases

    NASA Astrophysics Data System (ADS)

    Tsvetkov, V. M.; Pikulev, A. A.

    2012-04-01

    A flow type barrier-discharge UV photoreactor intended for irradiation of liquids and gases has been developed. In the proposed reactor design, both the discharge region and processed medium occur inside the bulb of an excilamp and the electrodes are made of an UV-reflecting material. The UV radiation intensity in the photoreactor is determined using the photochemical reaction of acetic acid decomposition (CH3COOH + hν → CH4 + CO2) that takes place under the action of KrCl exciplex emission at 222 nm, and the UV exposure dose is evaluated by measuring the evolved gas volume. The experiments showed that the UV radiation intensity in the proposed photoreactor is higher by an order of magnitude than that at the surface of an excilamp with analogous geometry.

  17. Formation Monocrystalline Carbon Micro-and Nanostructures Under Femtosecond Laser Irradiation of graphite in Liquid Nitrogen

    NASA Astrophysics Data System (ADS)

    Khorkov, Kirill S.; Abramov, Dmitrii V.; Kochuev, Dmitriy A.; Arakelian, Sergey M.; Prokoshev, Valery G.

    The combination of high energy and ultra short duration of femtosecond laser pulses allow to reach in the area of impact the local conditions which can change the phase composition of irradiated material. Traditional methods of structural phase transformation of the graphite at high pressures do not provide the abrupt simultaneous cancellation of the applied pressure and temperature. As a result, some of the synthesized nanostructures and metastable forms of carbon are destroyed. The suggested method allows to eliminate this disadvantage. Femtosecond laser radiation provides ultrafast heating of the target material, and the use of liquid nitrogen dramatically accelerates the process of it cooling. The formation of new carbon micro- and nanostructures has been registered at experimental approbation of the proposed method. The check of elemental composition of the created crystals showed that they are formed solely of carbon. The experimental results show the possibility of creation of new (less studied) carbon forms with a variety of properties.

  18. Water: The Liquid of Life. Fifth Grade.

    ERIC Educational Resources Information Center

    Illinois State Environmental Protection Agency, Springfield.

    These materials are for use by elementary and middle school teachers in the state of Illinois. This document contains five modules for teaching water conservation. Topics include: (1) "Life Depends on Water,""What is Water?" and "The Hydrologic Cycle"; (2) "The Treatment of Drinking Water"; (3)…

  19. Water: The Liquid of Life. Fifth Grade.

    ERIC Educational Resources Information Center

    Illinois State Environmental Protection Agency, Springfield.

    These materials are for use by elementary and middle school teachers in the state of Illinois. This document contains five modules for teaching water conservation. Topics include: (1) "Life Depends on Water,""What is Water?" and "The Hydrologic Cycle"; (2) "The Treatment of Drinking Water"; (3)…

  20. Inactivation of Salmonella serovars in liquid whole egg by heat following irradiation treatments.

    PubMed

    Alvarez, Ignacio; Niemira, Brendan A; Fan, Xuetong; Sommers, Christopher H

    2006-09-01

    Salmonella is a frequent contaminant on eggs and is responsible for foodborne illnesses in humans. Ionizing radiation and thermal processing can be used to inactivate Salmonella in liquid whole egg, but when restricted to doses that do not affect egg quality, these technologies are only partially effective in reducing Salmonella populations. In this study, the effect of ionizing radiation in combination with thermal treatment on the survival of Salmonella serovars was investigated. Of the six Salmonella serovars tested, Salmonella Senftenberg was the most resistant to radiation (Dgamma = 0.65 kGy) and heat (D(55 degrees C) = 11.31 min, z = 4.9 degrees C). Irradiation followed by thermal treatment at 55 or 57 degrees C improved the pasteurization process. Radiation doses as low as 0.1 kGy prior to thermal treatments synergistically reduced the D(55 degrees C) and D(57 degrees C) of Salmonella Senftenberg 3.6- and 2.5-fold, respectively. The D(55 degrees C) and D(57 degrees C) of Salmonella Typhimurium were reduced 2- and 1.4-fold and those of Salmonella Enteritidis were reduced 2- and 1.6-fold, respectively. Irradiation prior to thermal treatment would enable the reduction of heat treatment times by 86 and 30% at 55 and 57 degrees C, respectively, and would inactivate 9 log units of Salmonella serovars.

  1. Process for blending coal with water immiscible liquid

    DOEpatents

    Heavin, Leonard J.; King, Edward E.; Milliron, Dennis L.

    1982-10-26

    A continuous process for blending coal with a water immiscible liquid produces a uniform, pumpable slurry. Pulverized raw feed coal and preferably a coal derived, water immiscible liquid are continuously fed to a blending zone (12 and 18) in which coal particles and liquid are intimately admixed and advanced in substantially plug flow to form a first slurry. The first slurry is withdrawn from the blending zone (12 and 18) and fed to a mixing zone (24) where it is mixed with a hot slurry to form the pumpable slurry. A portion of the pumpable slurry is continuously recycled to the blending zone (12 and 18) for mixing with the feed coal.

  2. Ice-Crystal Fallstreaks from Supercooled Liquid Water Parent Clouds

    NASA Technical Reports Server (NTRS)

    Campbell, James R.; O'C. Starr, David; Welton, Ellsworth J.; Spinhirne, James D.; Ferrare, Richard A.

    2003-01-01

    On 31 December 2001, ice-crystal fallstreaks (e.g., cirrus uncinus, or colloquially "Mare's Tails") from supercooled liquid water parent clouds were observed by ground-based lidars pointed vertically from the Atmospheric Radiation Measurement Southern Great Plains (SGP) facility near Lamont, Oklahoma. The incidence of liquid phase cloud with apparent ice-phase precipitation is investigated. Scenarios for mixed-phase particle nucleation, and fallstreak formation and sustenance are discussed. The observations are unique in the context of the historical reverence given to the commonly observed c h s uncinus fallstreak (wholly ice) versus this seemingly contradictory coincidence of liquid water begetting ice-crystal streaks.

  3. Thin-layer liquid crystal thermometry of cells in vitro during hyperthermal microwave irradiation.

    PubMed

    Robinson, J E; McCulloch, D; Harrison, G H; Cheung, A Y

    1982-01-01

    A nonperturbing technique of thin-layer liquid crystal thermometry was developed to quantitate heating of Chinese hamster ovary cells and the bacterium Serratia marcescens when exposed to 2450-MHz microwave fields at 0.2-0.5 W/cm2. Cells suspended in culture medium were injected into 5-cm glass microcapillary tubes coated on the inside with a thin layer of liquid crystal. The tubes were sealed and placed parallel to the electric field in a watertight waveguide exposure chamber where they were heated by circulating temperature-controlled water. Even at high circulation rates, liquid crystal color changes indicated local microwave capillary tube heating of 0.1-0.25 degrees C. Precision of measurement was 0.02 degrees C. Observations during microwave heating were significantly different from observations without microwaves at the 1% level, and heating increased as circulating water flow was reduced from 300 ml/s to 100 ml/s. The results of a cell survival assay following hyperthermal treatment were in good agreement with expectations based on the observations of microwave heating using liquid crystals.

  4. Cluster Monte Carlo and numerical mean field analysis for the water liquid-liquid phase transition

    NASA Astrophysics Data System (ADS)

    Mazza, Marco G.; Stokely, Kevin; Strekalova, Elena G.; Stanley, H. Eugene; Franzese, Giancarlo

    2009-04-01

    Using Wolff's cluster Monte Carlo simulations and numerical minimization within a mean field approach, we study the low temperature phase diagram of water, adopting a cell model that reproduces the known properties of water in its fluid phases. Both methods allow us to study the thermodynamic behavior of water at temperatures, where other numerical approaches - both Monte Carlo and molecular dynamics - are seriously hampered by the large increase of the correlation times. The cluster algorithm also allows us to emphasize that the liquid-liquid phase transition corresponds to the percolation transition of tetrahedrally ordered water molecules.

  5. Phenomenon of PDT-induced post-irradiation apoptosis in biological liquids cancer cells using sulphonated phthalocyanine aluminum photosensitizer

    NASA Astrophysics Data System (ADS)

    Douplik, Alexandre Y.; Loschenov, Victor B.; Vorozhtsov, Georgy N.; Kogan, Eugenia A.; Kusin, Michael; Ablitsov, Y.; Ilyina, O. S.

    1997-12-01

    Discovered during last year's phenomenon of PDT-induced apoptosis (programmed cell destruction) in cell culture immediately after light irradiation using phthalocyanine photosensitizers can be used for treatment of cancer. Experiments were carried out on mice with ascites. Ascitic liquid with the added photosensitizer was irradiated by light source with wavelength 660 - 680 nm and used according to ex vivo procedure. Actuation and development of apoptosis process in ascitic liquid were estimated by cytomorphological tests. It has been observed the phenomenon of growth of relative fraction of cells damage level expressed mainly as apoptosis after PDT procedure ex vivo. We suggest to call this phenomenon as PDT-induced post-irradiation apoptosis (PIP- apoptosis). Dependence between level of expressing of PIP- apoptosis and sulphonated phthalocyanine aluminum photosensitizer (Photosense) concentration at used photosensitizer concentrations has not been found out.

  6. Liquid Water in the Extremely Shallow Martian Subsurface

    NASA Technical Reports Server (NTRS)

    Pavlov, A.; Shivak, J. N.

    2012-01-01

    Availability of liquid water is one of the major constraints for the potential Martian biosphere. Although liquid water is unstable on the surface of Mars due to low atmospheric pressures, it has been suggested that liquid films of water could be present in the Martian soil. Here we explored a possibility of the liquid water formation in the extremely shallow (1-3 cm) subsurface layer under low atmospheric pressures (0.1-10 mbar) and low ("Martian") surface temperatures (approx.-50 C-0 C). We used a new Goddard Martian simulation chamber to demonstrate that even in the clean frozen soil with temperatures as low as -25C the amount of mobile water can reach several percents. We also showed that during brief periods of simulated daylight warming the shallow subsurface ice sublimates, the water vapor diffuses through porous surface layer of soil temporarily producing supersaturated conditions in the soil, which leads to the formation of additional liquid water. Our results suggest that despite cold temperatures and low atmospheric pressures, Martian soil just several cm below the surface can be habitable.

  7. Crack initiation behavior of neutron irradiated model and commercial stainless steels in high temperature water

    NASA Astrophysics Data System (ADS)

    Stephenson, Kale J.; Was, Gary S.

    2014-01-01

    The objective of this study was to isolate key factors affecting the irradiation-assisted stress corrosion cracking (IASCC) susceptibility of eleven neutron-irradiated austenitic stainless steel alloys. Four commercial purity and seven high purity stainless steels were fabricated with specific changes in composition and microstructure, and irradiated in a fast reactor spectrum at 320 °C to doses between 4.4 and 47.5 dpa. Constant extension rate tensile (CERT) tests were performed in normal water chemistry (NWC), hydrogen water chemistry (HWC), or primary water (PW) environments to isolate the effects of environment, elemental solute addition, alloy purity, alloy heat, alloy type, cold work, and irradiation dose. The irradiated alloys showed a wide variation in IASCC susceptibility, as measured by the relative changes in mechanical properties and crack morphology. Cracking susceptibility measured by %IG was enhanced in oxidizing environments, although testing in the lowest potential environment caused an increase in surface crack density. Alloys containing solute addition of Ni or Ni + Cr exhibited no IASCC. Susceptibility was reduced in materials cold worked prior to irradiation, and increased with increasing irradiation dose. Irradiation-induced hardening was accounted for by the dislocation loop microstructure, however no relation between crack initiation and radiation hardening was found.

  8. Reactions of recoil nitrogen-13 atoms in the ethanol-water system. Formation of [{sup 13}N]NH{sub 3} upon irradiation of water and dilute aqueous solutions of ethanol under a pressure of various gases

    SciTech Connect

    Korsakov, M.V.; Krasikova, R.N.; Fedorova, O.S.

    1995-07-01

    The influence of the nature and pressure of a gas (helium, hydrogen) contacting with a solution on radiochemical yield of the {sup 13}N-labeled products of nuclear-chemical and radiolytic reactions occurring upon irradiation of water and dilute aqueous solution of ethanol by 17-MeV protons was examined. It was shown that irradiation of water under hydrogen pressure, about 50% of recoil nitrogen-13 atoms are stabilized in the gas phase in the form of [{sup 13}N]N{sub 2}, and the main product in the liquid phase is ammonia-{sup 13}N.

  9. Review: Drinking water for liquid-fed pigs.

    PubMed

    Meunier-Salaün, M-C; Chiron, J; Etore, F; Fabre, A; Laval, A; Pol, F; Prunier, A; Ramonet, Y; Nielsen, B L

    2016-11-07

    Liquid feeding has the potential to provide pigs with sufficient water to remain hydrated and prevent prolonged thirst. However, lack of permanent access to fresh water prevents animals from drinking when they are thirsty. Moreover, individual differences between pigs in a pen may result in uneven distribution of the water provided by the liquid feed, leading to some pigs being unable to meet their water requirements. In this review, we look at the need for and provision of water for liquid-fed pigs in terms of their production performance, behaviour, health and welfare. We highlight factors which may lead to water ingestion above or below requirements. Increases in the need for water may be caused by numerous factors such as morbidity, ambient temperature or competition within the social group, emphasising the necessity of permanent access to water as also prescribed in EU legislation. The drinkers can be the target of redirected behaviour in response to feed restriction or in the absence of rooting materials, thereby generating water losses. The method of water provision and drinker design is critical to ensure easy access to water regardless of the pig's physiological state, and to limit the amount of water used, which does not benefit the pig.

  10. Formation of hydroxylamine (NH2OH) in electron-irradiated ammonia-water ices.

    PubMed

    Zheng, Weijun; Kaiser, Ralf I

    2010-04-29

    We investigated chemical and physical processes in electron-irradiated ammonia-water ices at temperatures of 10 and 50 K. Chemically speaking, the formation of hydroxylamine (NH(2)OH) was observed in electron-irradiated ammonia-water ices. The synthesis of molecular hydrogen (H(2)), molecular nitrogen (N(2)), molecular oxygen (O(2)), hydrazine (N(2)H(4)), and hydrogen peroxide (H(2)O(2)), which was also monitored in previous irradiation of pure ammonia and water ices, was also evident. These newly formed species were trapped inside of the ices and were released into the gas phase during the warm-up phase of the sample after the irradiation. A quantitative analysis of the data showed that the production rates of the newly formed species at 10 K are higher compared to those at 50 K. Our studies also suggest that hydroxylamine is likely formed by the recombination of amino (NH(2)) with hydroxyl (OH) radicals inside of the ices. Considering the physical effects on the ice sampled during the irradiation, the experiments provided compelling evidence that the crystalline ammonia-water ice samples can be partially converted to amorphous ices during the electron irradiation; similar to the chemical processes, the irradiation-induced amorphization of the ices is faster at 10 K than that at 50 K--a finding which is similar to electron-irradiated crystalline water ices under identical conditions. However, the amorphization of water in water-ammonia ices was found to be faster than that in pure water ices at identical temperatures.

  11. Oiling out or molten hydrate-liquid-liquid phase separation in the system vanillin-water.

    PubMed

    Svärd, Michael; Gracin, Sandra; Rasmuson, Ake C

    2007-09-01

    Vanillin crystals in a saturated aqueous solution disappear and a second liquid phase emerges when the temperature is raised above 51 degrees C. The phenomenon has been investigated with crystallization and equilibration experiments, using DSC, TGA, XRD and hot-stage microscopy for analysis. The new liquid solidifies on cooling, appears to melt at 51 degrees C, and has a composition corresponding to a dihydrate. However, no solid hydrate can be detected by XRD, and it is shown that the true explanation is that a liquid-liquid phase separation occurs above 51 degrees C where the vanillin-rich phase has a composition close to a dihydrate. To our knowledge, liquid-liquid phase separation has not previously been reported for the system vanillin-water, even though thousands of tonnes of vanillin are produced globally every year. (c) 2007 Wiley-Liss, Inc. and the American Pharmacists Association.

  12. Dynamic imaging of a single gold nanoparticle in liquid irradiated by off-resonance femtosecond laser.

    PubMed

    Boutopoulos, Christos; Hatef, Ali; Fortin-Deschênes, Matthieu; Meunier, Michel

    2015-07-21

    Plasmonic nanoparticles can lead to extreme confinement of the light in the near field. This unique ability of plasmonic nanoparticles can be used to generate nanobubbles in liquid. In this work, we demonstrate with single-particle monitoring that 100 nm gold nanoparticles (AuNPs) irradiated by off-resonance femtosecond (fs) laser in the tissue therapeutic optical window (λ = 800 nm), can act as a durable nanolenses in liquid and provoke nanocavitation while remaining intact. We have employed combined ultrafast shadowgraphic imaging, in situ dark field imaging and dynamic tracking of AuNP Brownian motion to ensure the study of individual AuNPs/nanolenses under multiple fs laser pulses. We demonstrate that 100 nm AuNPs can generate multiple, highly confined (radius down to 550 nm) and transient (life time < 50 ns) nanobubbles. The latter is of significant importance for future development of in vivo AuNP-assisted laser nanosurgery and theranostic applications, where AuNP fragmentation should be avoided to prevent side effects, such as cytotoxicity and immune system's response. The experimental results have been correlated with theoretical modeling to provide an insight to the AuNP-safe cavitation mechanism as well as to investigate the deformation mechanism of the AuNPs at high laser fluences.

  13. Adsorption of alcohol from water by poly(ionic liquid)s.

    PubMed

    Bi, Wentao; Tang, Baokun; Row, Kyung Ho

    2013-06-01

    Bioethanol is used widely as a solvent and is considered a potential liquid fuel. Ethanol can be produced from biomass by fermentation, which results in low concentrations of alcohol in water. Conventional distillation is normally used to separate ethanol from water, but it required high energy consumption. Therefore, alternative approaches to this separation are being pursued. This study examined the potential use of poly(ionic liquid)s (PILs) for the extraction and separation of alcohols from the aqueous phase. Hydrophobic PILs were developed and evaluated by the adsorption of ethanol from ethanol/water solutions. All the necessary parameters, such as cations and anions of the ionic liquid, morphology of the polymer and processing conditions, were evaluated.

  14. Character and Structure of Hydrogen Bonding in Liquid Water

    NASA Astrophysics Data System (ADS)

    Guo, Jinghua; Luo, Yi; Augustsson, Andreas; Rubensson, Jan-Erik; Sathe, Conny; Agren, Hans; Siegbahn, Hans; Nordgren, Joseph

    2003-03-01

    Pauling stated in the 50s that electron sharing between water molecules results in a covalency in the hydrogen bond. Many attempts have been made in the past to verify PaulingÂ's prediction, but without much success due to the limitation of experimental access to the electronic structure of liquids. We reported the first X-ray emission spectra of liquid water. X-ray emission is a direct probe of the local electronic structure of complex systems. Our experimental and theoretical studies on liquid water provide clear evidence that an electron sharing takes place between water molecules. Such a sharing mainly involves the so-called 3a1 orbital, which is a mixing of oxygen 2p and hydrogen 2s atomic orbitals. The outermost "lone pair" orbital (1b_1), however, hardly shows any change upon solvation, which is in contradiction with the normal definition of so-called coordinate-covalent bonding (also called donor-acceptor or Lewis acid-base bonding). Moreover, the X-ray emission spectra of liquid water nicely show the origin for the increasing of dipole moment in liquid water, and they have also been used to separately determine a particular structure with broken hydrogen bonding.

  15. Loss of structural water and carbonate of Nd:YAG laser-irradiated human enamel.

    PubMed

    Corrêa-Afonso, Alessandra Marques; Bachmann, Luciano; de Almeida, Cíntia Guimarães; Dibb, Regina Guenka Palma; Borsatto, Maria Cristina

    2015-05-01

    The objective of this study was to use Fourier Transform Infrared (FTIR) spectroscopy and Scanning Electron Microscopy (SEM) to assess whether Nd:YAG laser irradiation associated with a dye or not alters the chemical constitution of the enamel. Fourteen enamel sections were randomly divided into two groups: (1) Nd:YAG and (2) dye + Nd:YAG. First, the untreated enamel surfaces were analyzed by FTIR to acquire the control absorption spectrum. Next, Group 2 received a layer of inactivated coal diluted in deionized water before laser treatment. Enamel samples belonging to groups 1 and 2 were then irradiated with a 1,064-nm Nd:YAG laser (80 mJ, 10 Hz) in the contact mode; the carbonate absorption band and the water absorption band were measured in each sample after irradiation. The water band was measured again 24 h, 48 h, and 7 days after irradiation. Group 1 had statistically similar water and carbonate contents before and after irradiation. Group 2 displayed significantly lower (p < 0.05) water content after irradiation, which remained constant along time at 24 and 48 h. After 7 days, the water content increased slightly, being statistically higher than in the other experimental periods, except for the control. The carbonate/phosphate ratio was measured only at the beginning, and after irradiation, it decreased only in Group 2 indicating carbonate loss (p < 0.05). Irradiation with 1,064-nm Nd:YAG laser associated with a dye reduces the carbonate and structural water content in the enamel.

  16. The putative liquid-liquid transition is a liquid-solid transition in atomistic models of water. II.

    PubMed

    Limmer, David T; Chandler, David

    2013-06-07

    This paper extends our earlier studies of free energy functions of density and crystalline order parameters for models of supercooled water, which allows us to examine the possibility of two distinct metastable liquid phases [D. T. Limmer and D. Chandler, J. Chem. Phys. 135, 134503 (2011) and preprint arXiv:1107.0337 (2011)]. Low-temperature reversible free energy surfaces of several different atomistic models are computed: mW water, TIP4P/2005 water, Stillinger-Weber silicon, and ST2 water, the last of these comparing three different treatments of long-ranged forces. In each case, we show that there is one stable or metastable liquid phase, and there is an ice-like crystal phase. The time scales for crystallization in these systems far exceed those of structural relaxation in the supercooled metastable liquid. We show how this wide separation in time scales produces an illusion of a low-temperature liquid-liquid transition. The phenomenon suggesting metastability of two distinct liquid phases is actually coarsening of the ordered ice-like phase, which we elucidate using both analytical theory and computer simulation. For the latter, we describe robust methods for computing reversible free energy surfaces, and we consider effects of electrostatic boundary conditions. We show that sensible alterations of models and boundary conditions produce no qualitative changes in low-temperature phase behaviors of these systems, only marginal changes in equations of state. On the other hand, we show that altering sampling time scales can produce large and qualitative non-equilibrium effects. Recent reports of evidence of a liquid-liquid critical point in computer simulations of supercooled water are considered in this light.

  17. The putative liquid-liquid transition is a liquid-solid transition in atomistic models of water. II

    SciTech Connect

    Limmer, David T.; Chandler, David

    2013-06-07

    This paper extends our earlier studies of free energy functions of density and crystalline order parameters for models of supercooled water, which allows us to examine the possibility of two distinct metastable liquid phases [D. T. Limmer and D. Chandler, J. Chem. Phys.135, 134503 (2011) and preprint http://arxiv.org/abs/arXiv:1107.0337 (2011)]. Low-temperature reversible free energy surfaces of several different atomistic models are computed: mW water, TIP4P/2005 water, Stillinger-Weber silicon, and ST2 water, the last of these comparing three different treatments of long-ranged forces. In each case, we show that there is one stable or metastable liquid phase, and there is an ice-like crystal phase. The time scales for crystallization in these systems far exceed those of structural relaxation in the supercooled metastable liquid. We show how this wide separation in time scales produces an illusion of a low-temperature liquid-liquid transition. The phenomenon suggesting metastability of two distinct liquid phases is actually coarsening of the ordered ice-like phase, which we elucidate using both analytical theory and computer simulation. For the latter, we describe robust methods for computing reversible free energy surfaces, and we consider effects of electrostatic boundary conditions. We show that sensible alterations of models and boundary conditions produce no qualitative changes in low-temperature phase behaviors of these systems, only marginal changes in equations of state. On the other hand, we show that altering sampling time scales can produce large and qualitative non-equilibrium effects. Recent reports of evidence of a liquid-liquid critical point in computer simulations of supercooled water are considered in this light.

  18. Searching for Liquid Water in Europa by Using Surface Observatories

    NASA Astrophysics Data System (ADS)

    Khurana, Krishan K.; Kivelson, Margaret G.; Russell, Christopher T.

    2002-03-01

    Liquid water, as far as we know, is an indispensable ingredient of life. Therefore, locating reservoirs of liquid water in extraterrestrial bodies is a necessary prerequisite to searching for life. Recent geological and geophysical observations from the Galileo spacecraft, though not unambiguous, hint at the possibility of a subsurface ocean in the Jovian moon Europa. After summarizing present evidence for liquid water in Europa, we show that electromagnetic and seismic observations made from as few as two surface observatories comprising a magnetometer and a seismometer offer the best hope of unambiguous characterization of the three-dimensional structure of the ocean and the deeper interior of this icy moon. The observatories would also help us infer the composition of the icy crust and the ocean water.

  19. Charge-on-spring polarizable water models revisited: From water clusters to liquid water to ice

    NASA Astrophysics Data System (ADS)

    Yu, Haibo; van Gunsteren, Wilfred F.

    2004-11-01

    The properties of two improved versions of charge-on-spring (COS) polarizable water models (COS/G2 and COS/G3) that explicitly include nonadditive polarization effects are reported. In COS models, the polarization is represented via a self-consistently induced dipole moment consisting of a pair of separated charges. A previous polarizable water model (COS/B2), upon which the improved versions are based, was developed by Yu, Hansson, and van Gunsteren [J. Chem. Phys. 118, 221 (2003)]. To improve the COS/B2 model, which overestimated the dielectric permittivity, one additional virtual atomic site was used to reproduce the water monomer quadrupole moments besides the water monomer dipole moment in the gas phase. The molecular polarizability, residing on the virtual atomic site, and Lennard-Jones parameters for oxygen-oxygen interactions were varied to reproduce the experimental values for the heat of vaporization and the density of liquid water at room temperature and pressure. The improved models were used to study the properties of liquid water at various thermodynamic states as well as gaseous water clusters and ice. Overall, good agreement is obtained between simulated properties and those derived from experiments and ab initio calculations. The COS/G2 and COS/G3 models may serve as simple, classical, rigid, polarizable water models for the study of organic solutes and biopolymers. Due to its simplicity, COS type of polarization can straightforwardly be used to introduce explicit polarization into (bio)molecular force fields.

  20. Behavior of supercooled aqueous solutions stemming from hidden liquid-liquid transition in water.

    PubMed

    Biddle, John W; Holten, Vincent; Anisimov, Mikhail A

    2014-08-21

    A popular hypothesis that explains the anomalies of supercooled water is the existence of a metastable liquid-liquid transition hidden below the line of homogeneous nucleation. If this transition exists and if it is terminated by a critical point, the addition of a solute should generate a line of liquid-liquid critical points emanating from the critical point of pure metastable water. We have analyzed thermodynamic consequences of this scenario. In particular, we consider the behavior of two systems, H2O-NaCl and H2O-glycerol. We find the behavior of the heat capacity in supercooled aqueous solutions of NaCl, as reported by Archer and Carter [J. Phys. Chem. B 104, 8563 (2000)], to be consistent with the presence of the metastable liquid-liquid transition. We elucidate the non-conserved nature of the order parameter (extent of "reaction" between two alternative structures of water) and the consequences of its coupling with conserved properties (density and concentration). We also show how the shape of the critical line in a solution controls the difference in concentration of the coexisting liquid phases.

  1. Behavior of supercooled aqueous solutions stemming from hidden liquid-liquid transition in water

    NASA Astrophysics Data System (ADS)

    Biddle, John W.; Holten, Vincent; Anisimov, Mikhail A.

    2014-08-01

    A popular hypothesis that explains the anomalies of supercooled water is the existence of a metastable liquid-liquid transition hidden below the line of homogeneous nucleation. If this transition exists and if it is terminated by a critical point, the addition of a solute should generate a line of liquid-liquid critical points emanating from the critical point of pure metastable water. We have analyzed thermodynamic consequences of this scenario. In particular, we consider the behavior of two systems, H2O-NaCl and H2O-glycerol. We find the behavior of the heat capacity in supercooled aqueous solutions of NaCl, as reported by Archer and Carter [J. Phys. Chem. B 104, 8563 (2000)], to be consistent with the presence of the metastable liquid-liquid transition. We elucidate the non-conserved nature of the order parameter (extent of "reaction" between two alternative structures of water) and the consequences of its coupling with conserved properties (density and concentration). We also show how the shape of the critical line in a solution controls the difference in concentration of the coexisting liquid phases.

  2. Inactivation of Aspergillus flavus in drinking water after treatment with UV irradiation followed by chlorination.

    PubMed

    Al-Gabr, Hamid Mohammad; Zheng, Tianling; Yu, Xin

    2013-10-01

    The disinfection process for inactivating microorganisms at drinking water treatment plants is aimed for safety of drinking water for humans from a microorganism, such as bacteria, viruses, algae, fungi by using chlorination, ozonation, UV irradiation, etc. In the present study, a combination of two disinfectants, UV irradiation followed by chlorination, was evaluated for inactivating Aspergillus flavus under low contact time and low dosage of UV irradiation. The results indicated an inverse correlation between the inactivation of A. flavus by using UV irradiation only or chlorination alone. By using UV radiation, the 2 log10 control of A. flavus was achieved after 30 s of irradiation, while chlorination was observed to be more effective than UV, where the 2 log was achieved at chlorine concentration of 0.5, 1, 2 and 3 mg/l, in contact time of 60, 5, 1 and 1 min, respectively. However, combined use (UV irradiation followed by chlorination) was more effective than using either UV or chlorination alone; 5 s UV irradiation followed by chlorination produced 4 log10 reduction of A. flavus at chlorine concentrations of 2 and 3 mg/l under a contact time of 15 min. The results indicated that efficiency of UV irradiation improves when followed by chlorination at low concentrations. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. Bond-Valence Constraints on Liquid Water Structure

    SciTech Connect

    Bickmore, Barry R.; Rosso, Kevin M.; Brown, I. David; Kerisit, Sebastien N.

    2009-03-05

    The recent controversy about the structure of liquid water pits a new model involving water molecules in relatively stable rings-and-chains structures against the standard model that posits water molecules in distorted tetrahedral coordination. Molecular dynamics (MD) simulations—both classical and ab initio—almost uniformly support the standard model, but since none of them can yet reproduce all the anomalous properties of water, they leave room for doubt. We argue that it is possible to evaluate these simulations by testing them against their adherence to the bond-valence model, a well known, and quantitatively accurate, empirical summary of the behavior of atoms in the bonded networks of inorganic solids. Here we use the results of ab initio molecular dynamics simulations of ice, water, and several solvated aqueous species to show that the valence sum rule (the first axiom of the bond-valence model,) is followed in both solid and liquid bond networks. We then test MD simulations of water, employing several popular potential models, against this criterion and the experimental O-O radial distribution function. It appears that most of those tested cannot satisfy both criteria well, except TIP4P and TIP5P. If the valence sum rule really can be applied to simulated liquid structures, then it follows that the bonding behaviors of atoms in liquids are in some ways identical to those in solids. We support this interpretation by showing that the simulations produce O-H…O geometries completely consistent with the range of geometries available in solids, and the distributions of instantaneous valence sums reaching the atoms in both the ice and liquid water simulations are essentially identical. Taken together, this is powerful evidence in favor of the standard distorted tetrahedral model of liquid water structure.

  4. Light water reactor mixed-oxide fuel irradiation experiment

    SciTech Connect

    Hodge, S.A.; Cowell, B.S.; Chang, G.S.; Ryskamp, J.M.

    1998-06-01

    The United States Department of Energy Office of Fissile Materials Disposition is sponsoring and Oak Ridge National Laboratory (ORNL) is leading an irradiation experiment to test mixed uranium-plutonium oxide (MOX) fuel made from weapons-grade (WG) plutonium. In this multiyear program, sealed capsules containing MOX fuel pellets fabricated at Los Alamos National Laboratory (LANL) are being irradiated in the Advanced Test Reactor (ATR) at the Idaho National Engineering and Environmental Laboratory (INEEL). The planned experiments will investigate the utilization of dry-processed plutonium, the effects of WG plutonium isotopics on MOX performance, and any material interactions of gallium with Zircaloy cladding.

  5. Communication: Protein dynamical transition vs. liquid-liquid phase transition in protein hydration water

    NASA Astrophysics Data System (ADS)

    Schirò, Giorgio; Fomina, Margarita; Cupane, Antonio

    2013-09-01

    In this work, we compare experimental data on myoglobin hydrated powders from elastic neutron scattering, broadband dielectric spectroscopy, and differential scanning calorimetry. Our aim is to obtain new insights on the connection between the protein dynamical transition, a fundamental phenomenon observed in proteins whose physical origin is highly debated, and the liquid-liquid phase transition (LLPT) possibly occurring in protein hydration water and related to the existence of a low temperature critical point in supercooled water. Our results provide a consistent thermodynamic/dynamic description which gives experimental support to the LLPT hypothesis and further reveals how fundamental properties of water and proteins are tightly related.

  6. Water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels

    NASA Astrophysics Data System (ADS)

    Wang, Qingguo; Zhou, Xue; Zeng, Jinxia; Wang, Jizeng

    2016-02-01

    In this paper, the electron beam irradiation technology being more suitable for the industry application is explored to fabricate the acrylic acid (AAc) monomer-grafted polyvinyl alcohol (PVA-g-AAc) hydrogels. ATR-IR spectra of the PVA-g-AAc hydrogels shows an obvious absorption peak of the sbnd Cdbnd O group at 1701 cm-1, indicating that the AAc monomers were grafted onto the PVA macromolecules. This paper also studied some effects of the mass ratio of PVA/AAc, pH of buffer solution and irradiation dosage on the water swelling properties of the electron beam irradiated PVA-g-AAc hydrogels. The water swelling ratio of PVA-g-AAc hydrogels decreases with increased irradiation dosage and mass ratio of PVA/AAc, whereas swelling ratio increases with increased pH of buffer solution and soaking time. The water-swelling behavior of PVA-g-AAc hydrogels occurred easily in an alkaline environment, particularly in a buffer solution with pH 9.2. Both PVA-g-AAc hydrogels (PVA/AAc = 1/5, w/w) irradiated with 5 kilogray (kGy) and PVA-g-AAc hydrogels (PVA/AAc = 1/1, w/w) irradiated with 15 kGy could easily absorb water and lead to high water swelling ratios (up to about 600%), which are potential candidates to meet the requirements for some biomedical applications.

  7. Dependence of marine stratocumulus reflectivities on liquid water paths

    NASA Technical Reports Server (NTRS)

    Coakley, James A., Jr.; Snider, Jack B.

    1990-01-01

    Simple parameterizations that relate cloud liquid water content to cloud reflectivity are often used in general circulation climate models to calculate the effect of clouds in the earth's energy budget. Such parameterizations have been developed by Stephens (1978) and by Slingo and Schrecker (1982) and others. Here researchers seek to verify the parametric relationship through the use of simultaneous observations of cloud liquid water content and cloud reflectivity. The column amount of cloud liquid was measured using a microwave radiometer on San Nicolas Island following techniques described by Hogg et al., (1983). Cloud reflectivity was obtained through spatial coherence analysis of Advanced Very High Resolution Radiometer (AVHRR) imagery data (Coakley and Beckner, 1988). They present the dependence of the observed reflectivity on the observed liquid water path. They also compare this empirical relationship with that proposed by Stephens (1978). Researchers found that by taking clouds to be isotropic reflectors, the observed reflectivities and observed column amounts of cloud liquid water are related in a manner that is consistent with simple parameterizations often used in general circulation climate models to determine the effect of clouds on the earth's radiation budget. Attempts to use the results of radiative transfer calculations to correct for the anisotropy of the AVHRR derived reflectivities resulted in a greater scatter of the points about the relationship expected between liquid water path and reflectivity. The anisotropy of the observed reflectivities proved to be small, much smaller than indicated by theory. To critically assess parameterizations, more simultaneous observations of cloud liquid water and cloud reflectivities and better calibration of the AVHRR sensors are needed.

  8. Limit of metastability for liquid and vapor phases of water.

    PubMed

    Cho, Woo Jong; Kim, Jaegil; Lee, Joonho; Keyes, Thomas; Straub, John E; Kim, Kwang S

    2014-04-18

    We report the limits of superheating of water and supercooling of vapor from Monte Carlo simulations using microscopic models with configurational enthalpy as the order parameter. The superheating limit is well reproduced. The vapor is predicted to undergo spinodal decomposition at a temperature of Tspvap=46±10 °C (0 °C≪Tspvap≪100 °C) under 1 atm. The water-water network begins to form at the supercooling limit of the vapor. Three-dimensional water-water and cavity-cavity unbroken networks are interwoven at critically superheated liquid water; if either network breaks, the metastable state changes to liquid or vapor.

  9. A Mechanism for Recent Production of Liquid Water on Mars

    NASA Technical Reports Server (NTRS)

    Hecht, M. H.; Bridges, N. T.

    2003-01-01

    Though Mars is a cold, dry planet, with respect to the thermal stability of liquid water at low altitudes it is not terribly different from comparably cold places on Earth. In dry air such water would evaporate faster on Mars, at a rate comparable to a 60 C hot spring on Earth, but the heat loss associated with that evaporation would be mitigated by the poor thermal convection in the thin Martian air. Even at higher altitudes where the atmospheric pressure does not reach the triple point of water, liquid water might theoretically exist in a low-vapor pressure form such as wet soil, in a briny solution, or simply under a layer of dust or snow. The theoretical stability of liquid water does not suggest its occurrence, either on Mars or in Antarctica. In fact, global models have suggested that locations capable of providing sufficient heat for melting are, precisely for that reason, too dry for water to be present. However, the temperature of irregular local structures such as trenches or craters can be markedly warmer than those of the uniform surfaces of global models. The work described here suggests a plausible scenario in which seasonal liquid water might be produced locally, in sheltered locations, through a process of condensation, cold-trapping, buffering, and melting. While the amounts produced in the present climate would be small, copious amounts of meltwater may have been produced at other phases of the orbital cycle, as recently as 20,000 years ago.

  10. A Mechanism for Recent Production of Liquid Water on Mars

    NASA Technical Reports Server (NTRS)

    Hecht, M. H.; Bridges, N. T.

    2003-01-01

    Though Mars is a cold, dry planet, with respect to the thermal stability of liquid water at low altitudes it is not terribly different from comparably cold places on Earth. In dry air such water would evaporate faster on Mars, at a rate comparable to a 60 C hot spring on Earth, but the heat loss associated with that evaporation would be mitigated by the poor thermal convection in the thin Martian air. Even at higher altitudes where the atmospheric pressure does not reach the triple point of water, liquid water might theoretically exist in a low-vapor pressure form such as wet soil, in a briny solution, or simply under a layer of dust or snow. The theoretical stability of liquid water does not suggest its occurrence, either on Mars or in Antarctica. In fact, global models have suggested that locations capable of providing sufficient heat for melting are, precisely for that reason, too dry for water to be present. However, the temperature of irregular local structures such as trenches or craters can be markedly warmer than those of the uniform surfaces of global models. The work described here suggests a plausible scenario in which seasonal liquid water might be produced locally, in sheltered locations, through a process of condensation, cold-trapping, buffering, and melting. While the amounts produced in the present climate would be small, copious amounts of meltwater may have been produced at other phases of the orbital cycle, as recently as 20,000 years ago.

  11. The puzzling unsolved mysteries of liquid water: Some recent progress

    NASA Astrophysics Data System (ADS)

    Stanley, H. E.; Kumar, P.; Xu, L.; Yan, Z.; Mazza, M. G.; Buldyrev, S. V.; Chen, S.-H.; Mallamace, F.

    2007-12-01

    Water is perhaps the most ubiquitous, and the most essential, of any molecule on earth. Indeed, it defies the imagination of even the most creative science fiction writer to picture what life would be like without water. Despite decades of research, however, water's puzzling properties are not understood and 63 anomalies that distinguish water from other liquids remain unsolved. We introduce some of these unsolved mysteries, and demonstrate recent progress in solving them. We present evidence from experiments and computer simulations supporting the hypothesis that water displays a special transition point (which is not unlike the “tipping point” immortalized by Malcolm Gladwell). The general idea is that when the liquid is near this “tipping point,” it suddenly separates into two distinct liquid phases. This concept of a new critical point is finding application to other liquids as well as water, such as silicon and silica. We also discuss related puzzles, such as the mysterious behavior of water near a protein.

  12. Effect of UV irradiation, sample thickness and storage temperature on storability, bacterial activity and functional properties of liquid egg.

    PubMed

    Abdanan Mehdizadeh, S; Minaei, S; Karimi Torshizi, M A; Mohajerani, E

    2015-07-01

    Effect of sample thickness, ultraviolet irradiation and storage temperature on bacterial activity, storability and functional properties (foamability and stability) of liquid egg were investigated. Eggs were contaminated with prepared Salmonella suspension 108/mL. Separated albumen and yolk samples were poured in three thicknesses (1, 2 and 3 mm) and irradiated at 3, 5 10, 15 min with ultraviolet radiation and were stored at 5, 15, 25, 37 °C for up to 8 days. Observations indicated that all ultraviolet irradiation times, reduced the total count of Salmonella bacteria in egg samples. Although, functional properties were improved, protein oxidation in both albumen and yolk increased. After the first 2 days of storage, total counts of Salmonella and protein oxidation of eggs decreased solely in the 5 °C treatment. It is concluded that irradiation treatment can be used to decrease bacterial contamination of liquid egg albeit not below the safe level for raw consumption. Furthermore, the best irradiation times to improve foam ability and stability were 10 and 5 min, respectively.

  13. Photochemical synthesis of silver particles in Tween 20/water/ionic liquid microemulsions.

    PubMed

    Harada, Masafumi; Kimura, Yoshifumi; Saijo, Kenji; Ogawa, Tetsuya; Isoda, Seiji

    2009-11-15

    Metal particles of silver (Ag) were synthesized by the photoreduction of silver perchlorate (AgClO(4)) in water-in-ionic liquid (ILs) microemulsions consisting of Tween 20, water and ionic liquids. The ILs were tetrafluoroborate anions associated with the cations 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIm][BF(4)]) and 1-octyl-3-methylimidazolium tetrafluoroborate ([OMIm][BF(4)]). The time evolution of Ag particle formation by photoreduction using UV-irradiation was investigated by UV-Vis, cryo-TEM, extended X-ray absorption fine structure (EXAFS) and small angle X-ray scattering (SAXS) measurements. The average diameter of the metallic Ag particles prepared in the water-in-[BMIm][BF(4)] and water-in-[OMIm][BF(4)] microemulsions was estimated from TEM to be 8.9 and 4.9nm, respectively, which was consistent with that obtained from the SAXS analysis. Using Guinier plots in a low q-range (<0.16nm(-1)), we demonstrate that the average diameter of the water droplets that consisted of aggregates of ionic precursors of AgClO(4) before reduction and Ag particles after reduction, in the microemulsions, was estimated to be about 20-40nm. The diameter of the water droplets increased as a function of photoreduction time because of the formation of Ag particles and their aggregates. EXAFS analysis indicated that Ag(+) ions were completely reduced to Ag(0) atoms during the photoreduction, followed by the formation of larger Ag particles.

  14. Elimination of disinfection byproduct formation potential in reclaimed water during solar light irradiation.

    PubMed

    Qian-Yuan, Wu; Chao, Li; Ye, Du; Wen-Long, Wang; Huang, Huang; Hong-Ying, Hu

    2016-05-15

    Ecological storage of reclaimed water in ponds and lakes is widely applied in water reuse. During reclaimed water storage, solar light can degrade pollutants and improve water quality. This study investigated the effects of solar light irradiation on the disinfection byproduct formation potential in reclaimed water, including haloacetonitriles (HANs), trichloronitromethane (TCNM), trihalomethanes (THMs), haloketones (HKs) and chloral hydrate (CH). Natural solar light significantly decreased the formation potential of HANs, TCNM, and HKs in reclaimed water, but had a limited effect on the formation potential of THMs and CH. Ultraviolet (UV) light in solar radiation played a dominant role in the decrease of the formation potential of HANs, TCNM and HKs. Among the disinfection byproducts, the removal kinetic constant of dichloroacetonitrile (DCAN) with irradiation dose was much larger than those for dichloropropanone (1,1-DCP), trichloropropanone (1,1,1-TCP) and TCNM. During solar irradiation, fluorescence spectra intensities of reclaimed water also decreased significantly. The removal of tyrosine (Tyr)-like and tryptophan (Trp)-like protein fluorescence spectra intensity volumes was correlated to the decrease in DCAN formation potential. Solar irradiation was demonstrated to degrade Trp, Tyr and their DCAN formation potential. The photolysis products of Trp after solar irradiation were detected as kynurenine and tryptamine, which had chloroform, CH and DCAN formation potential lower than those of Trp.

  15. Surface potential of the water liquid-vapor interface

    NASA Technical Reports Server (NTRS)

    Wilson, Michael A.; Pohorille, Andrew; Pratt, Lawrence R.

    1988-01-01

    An analysis of an extended molecular dynamics calculation of the surface potential (SP) of the water liquid-vapor interface is presented. The SP predicted by the TIP4P model is -(130 + or - 50) mV. This value is of reasonable magnitude but of opposite sign to the expectations based on laboratory experiments. The electrostatic potential shows a nonmonotonic variation with depth into the liquid.

  16. Bond orientational order in liquids: Towards a unified description of water-like anomalies, liquid-liquid transition, glass transition, and crystallization: Bond orientational order in liquids.

    PubMed

    Tanaka, Hajime

    2012-10-01

    There are at least three fundamental states of matter, depending upon temperature and pressure: gas, liquid, and solid (crystal). These states are separated by first-order phase transitions between them. In both gas and liquid phases a complete translational and rotational symmetry exist, whereas in a solid phase both symmetries are broken. In intermediate phases between liquid and solid, which include liquid crystal and plastic crystal phases, only one of the two symmetries is preserved. Among the fundamental states of matter, the liquid state is the most poorly understood. We argue that it is crucial for a better understanding of liquids to recognize that a liquid generally has the tendency to have a local structural order and its presence is intrinsic and universal to any liquid. Such structural ordering is a consequence of many-body correlations, more specifically, bond angle correlations, which we believe are crucial for the description of the liquid state. We show that this physical picture may naturally explain difficult unsolved problems associated with the liquid state, such as anomalies of water-type liquids (water, Si, Ge, ...), liquid-liquid transition, liquid-glass transition, crystallization and quasicrystal formation, in a unified manner. In other words, we need a new order parameter representing a low local free-energy configuration, which is a bond orientational order parameter in many cases, in addition to a density order parameter for the physical description of these phenomena. Here we review our two-order-parameter model of liquid and consider how transient local structural ordering is linked to all of the above-mentioned phenomena. The relationship between these phenomena is also discussed.

  17. Luminescence imaging of water during carbon-ion irradiation for range estimation

    SciTech Connect

    Yamamoto, Seiichi Komori, Masataka; Koyama, Shuji; Morishita, Yuki; Sekihara, Eri; Akagi, Takashi; Yamashita, Tomohiro; Toshito, Toshiyuki

    2016-05-15

    Purpose: The authors previously reported successful luminescence imaging of water during proton irradiation and its application to range estimation. However, since the feasibility of this approach for carbon-ion irradiation remained unclear, the authors conducted luminescence imaging during carbon-ion irradiation and estimated the ranges. Methods: The authors placed a pure-water phantom on the patient couch of a carbon-ion therapy system and measured the luminescence images with a high-sensitivity, cooled charge-coupled device camera during carbon-ion irradiation. The authors also carried out imaging of three types of phantoms (tap-water, an acrylic block, and a plastic scintillator) and compared their intensities and distributions with those of a phantom containing pure-water. Results: The luminescence images of pure-water phantoms during carbon-ion irradiation showed clear Bragg peaks, and the measured carbon-ion ranges from the images were almost the same as those obtained by simulation. The image of the tap-water phantom showed almost the same distribution as that of the pure-water phantom. The acrylic block phantom’s luminescence image produced seven times higher luminescence and had a 13% shorter range than that of the water phantoms; the range with the acrylic phantom generally matched the calculated value. The plastic scintillator showed ∼15 000 times higher light than that of water. Conclusions: Luminescence imaging during carbon-ion irradiation of water is not only possible but also a promising method for range estimation in carbon-ion therapy.

  18. Investigation of parameters of interaction of hydrogen isotopes with liquid lithium and lithium capillary-porous system under reactor irradiation

    SciTech Connect

    Tazhibayeva, I. L. Kulsartov, T. V.; Gordienko, Yu. N.; Zaurbekova, Zh. A.; Ponkratov, Yu. V.; Barsukov, N. I.; Tulubayev, Ye. Yu.; Baklanov, V. V.; Gnyrya, V. S.; Kenzhin, Ye. A.

    2015-12-15

    In this study, the effect of reactor irradiation on the processes of interaction of hydrogen with liquid lithium and a lithium capillary-porous system (CPS) is considered. The experiments are carried out by the gas-absorption method with use of a specially designed ampoule device. The results of investigation of the interaction of hydrogen with liquid lithium and a lithium CPS under conditions of reactor irradiation are described; namely, these are the temperature dependences of the rate constant for the interaction of hydrogen with liquid lithium at different reactor powers, the activation energies of the processes, and the pre-exponential factor in the Arrhenius dependence. The effect of increasing absorption of hydrogen by the samples under investigation as a result of the reactor irradiation is fixed. The effect can be explained by increasing mobility of hydrogen in liquid lithium due to hot spots in lithium bulk and the interaction of helium and tritium ions (formed as a result of the nuclear reaction of {sup 6}Li with neutron) with a surface hydride film.

  19. Metastability of Liquid Water on Mars

    NASA Technical Reports Server (NTRS)

    Hecht, M. H.

    2001-01-01

    This talk reviews reasonable spatial and temporal scales for melting and flowing of water on Mars, and relates them to plausible martian conditions. Additional information is contained in the original extended abstract.

  20. Are hydrated salts evidence of liquid water on Mars?

    NASA Astrophysics Data System (ADS)

    Gough, R. V.; Tolbert, M. A.

    2016-12-01

    Recent observation of hydrated salts associated with recurring slope lineae in several locations on Mars has created excitement over the possibility of contemporary liquid water flows (Ojha et al., 2015). Hydrated salts are crystalline solids such as sodium chloride dihydrate; although in the solid phase, these salts can form by precipitating from aqueous solutions. It is also possible, however, that such solid salts can form via absorption of atmospheric water vapor by anhydrous or less hydrated salts. Such a pathway would not require liquid water on any scale on current Mars, and therefore the hypothesis that RSL are due to recent liquid water would be weakened. Here we report the results of laboratory experiments that address the likelihood of these two hydrate formation pathways specifically for perchlorate and chloride salts observed in Martian RSL. We use a Raman microscope and environmental cell to study hydrated salt formation under Mars-relevant temperature and humidity conditions. We attempt to form these Mars-relevant hydrated salts by recrystallizing perchlorate or chloride brines and also by increasing the humidity around their anhydrous salts. We identify which particular hydrated salts, if present, would be the best markers of recent liquid water in the shallow subsurface because their water vapor-induced hydration is kinetically or thermodynamically hindered.

  1. Local structure analysis in ab initio liquid water

    NASA Astrophysics Data System (ADS)

    Santra, Biswajit; DiStasio, Robert A., Jr.; Martelli, Fausto; Car, Roberto

    2015-09-01

    Within the framework of density functional theory, the inclusion of exact exchange and non-local van der Waals/dispersion (vdW) interactions is crucial for predicting a microscopic structure of ambient liquid water that quantitatively agrees with experiment. In this work, we have used the local structure index (LSI) order parameter to analyse the local structure in such highly accurate ab initio liquid water. At ambient conditions, the LSI probability distribution, P(I ), was unimodal with most water molecules characterised by more disordered high-density-like local environments. With thermal excitations removed, the resultant bimodal P(I ) in the inherent potential energy surface (IPES) exhibited a 3:1 ratio between high-density- and low-density-like molecules, with the latter forming small connected clusters amid the predominant population. By considering the spatial correlations and hydrogen bond network topologies among water molecules with the same LSI identities, we demonstrate that the signatures of the experimentally observed low- and high-density amorphous phases of ice are present in the IPES of ambient liquid water. Analysis of the LSI autocorrelation function uncovered a persistence time of ∼ 4 ps - a finding consistent with the fact that natural thermal fluctuations are responsible for transitions between these distinct yet transient local aqueous environments in ambient liquid water.

  2. Dynamic imaging of a single gold nanoparticle in liquid irradiated by off-resonance femtosecond laser

    NASA Astrophysics Data System (ADS)

    Boutopoulos, Christos; Hatef, Ali; Fortin-Deschênes, Matthieu; Meunier, Michel

    2015-07-01

    Plasmonic nanoparticles can lead to extreme confinement of the light in the near field. This unique ability of plasmonic nanoparticles can be used to generate nanobubbles in liquid. In this work, we demonstrate with single-particle monitoring that 100 nm gold nanoparticles (AuNPs) irradiated by off-resonance femtosecond (fs) laser in the tissue therapeutic optical window (λ = 800 nm), can act as a durable nanolenses in liquid and provoke nanocavitation while remaining intact. We have employed combined ultrafast shadowgraphic imaging, in situ dark field imaging and dynamic tracking of AuNP Brownian motion to ensure the study of individual AuNPs/nanolenses under multiple fs laser pulses. We demonstrate that 100 nm AuNPs can generate multiple, highly confined (radius down to 550 nm) and transient (life time < 50 ns) nanobubbles. The latter is of significant importance for future development of in vivo AuNP-assisted laser nanosurgery and theranostic applications, where AuNP fragmentation should be avoided to prevent side effects, such as cytotoxicity and immune system's response. The experimental results have been correlated with theoretical modeling to provide an insight to the AuNP-safe cavitation mechanism as well as to investigate the deformation mechanism of the AuNPs at high laser fluences.Plasmonic nanoparticles can lead to extreme confinement of the light in the near field. This unique ability of plasmonic nanoparticles can be used to generate nanobubbles in liquid. In this work, we demonstrate with single-particle monitoring that 100 nm gold nanoparticles (AuNPs) irradiated by off-resonance femtosecond (fs) laser in the tissue therapeutic optical window (λ = 800 nm), can act as a durable nanolenses in liquid and provoke nanocavitation while remaining intact. We have employed combined ultrafast shadowgraphic imaging, in situ dark field imaging and dynamic tracking of AuNP Brownian motion to ensure the study of individual AuNPs/nanolenses under multiple fs

  3. Present status of the liquid lithium target facility in the international fusion materials irradiation facility (IFMIF)

    NASA Astrophysics Data System (ADS)

    Nakamura, Hiroo; Riccardi, B.; Loginov, N.; Ara, K.; Burgazzi, L.; Cevolani, S.; Dell'Orco, G.; Fazio, C.; Giusti, D.; Horiike, H.; Ida, M.; Ise, H.; Kakui, H.; Matsui, H.; Micciche, G.; Muroga, T.; Nakamura, Hideo; Shimizu, K.; Sugimoto, M.; Suzuki, A.; Takeuchi, H.; Tanaka, S.; Yoneoka, T.

    2004-08-01

    During the three year key element technology phase of the International Fusion Materials Irradiation Facility (IFMIF) project, completed at the end of 2002, key technologies have been validated. In this paper, these results are summarized. A water jet experiment simulating Li flow validated stable flow up to 20 m/s with a double reducer nozzle. In addition, a small Li loop experiment validated stable Li flow up to 14 m/s. To control the nitrogen content in Li below 10 wppm will require surface area of a V-Ti alloy getter of 135 m 2. Conceptual designs of diagnostics have been carried out. Moreover, the concept of a remote handling system to replace the back wall based on `cut and reweld' and `bayonet' options has been established. Analysis by FMEA showed safe operation of the target system. Recent activities in the transition phase, started in 2003, and plan for the next phase are also described.

  4. Effects of irradiation on protein electrophoretic properties, water absorption and cooking quality of lentils.

    PubMed

    Celik, Süeda; Yalçin, Erkan; Başman, Arzu; Köksel, Hamit

    2004-12-01

    Effects of gamma irradiation at doses of 1 kGy, 5 kGy, and 10 kGy on water absorption properties, cooking quality and electrophoretic patterns of insoluble proteins of red and green lentil samples were investigated. The densitometric analysis indicated that the effects of irradiation on sodium dodecyl sulfate-polycrylamide gel electrophoresis patterns of red and green lentil proteins were not significant. Generally, a 1 kGy irradiation dose did not significantly affect the water absorption properties of the lentil samples while significant increases were observed at the 5 kGy level. The dry and wet cooking times were found to be significantly decreased, as the irradiation level increased in all red and green lentil samples.

  5. Solid−liquid critical behavior of water in nanopores

    PubMed Central

    Mochizuki, Kenji; Koga, Kenichiro

    2015-01-01

    Nanoconfined liquid water can transform into low-dimensional ices whose crystalline structures are dissimilar to any bulk ices and whose melting point may significantly rise with reducing the pore size, as revealed by computer simulation and confirmed by experiment. One of the intriguing, and as yet unresolved, questions concerns the observation that the liquid water may transform into a low-dimensional ice either via a first-order phase change or without any discontinuity in thermodynamic and dynamic properties, which suggests the existence of solid−liquid critical points in this class of nanoconfined systems. Here we explore the phase behavior of a model of water in carbon nanotubes in the temperature−pressure−diameter space by molecular dynamics simulation and provide unambiguous evidence to support solid−liquid critical phenomena of nanoconfined water. Solid−liquid first-order phase boundaries are determined by tracing spontaneous phase separation at various temperatures. All of the boundaries eventually cease to exist at the critical points and there appear loci of response function maxima, or the Widom lines, extending to the supercritical region. The finite-size scaling analysis of the density distribution supports the presence of both first-order and continuous phase changes between solid and liquid. At around the Widom line, there are microscopic domains of two phases, and continuous solid−liquid phase changes occur in such a way that the domains of one phase grow and those of the other evanesce as the thermodynamic state departs from the Widom line. PMID:26100904

  6. Irradiation accelerated corrosion of 316L stainless steel in simulated primary water

    NASA Astrophysics Data System (ADS)

    Raiman, Stephen S.

    The objective of this work is to understand the effects of irradiation on the corrosion of 316L stainless steel in simulated primary water. 316L stainless steel samples were irradiated with a proton beam while simultaneously exposed to simulated PWR primary water to study the effects of radiation on corrosion. A 3.2 MeV proton beam was transmitted through a 37 microm thick sample that served as a "window" into a corrosion cell containing flowing 320° C water with 3 wppm H2. This design permitted radiolysis and displacement damage to occur on the sample surface in contact with the simulated primary water environment. Samples were irradiated for 4, 12, 24, and 72 hrs at dose rates between 400 and 4000 kGy/s, corresponding to damage rates of 7x10-7 to 7x10-6 dpa/s respectively. The structure and composition of the oxide films were characterized using Raman spectroscopy, STEM, and SEM. Sample areas exposed to direct proton irradiation had inner oxide films that were thinner, more porous, and were deficient in chromium when compared to unirradiated oxides. Outer oxides on irradiated samples exhibited a smaller particle size, and had a significant amount of hematite, which was not found on unirradiated samples. The presence of hematite on irradiated samples indicates an increase in electrochemical potential due to irradiation. Dissolution of chromium-rich spinels due to the elevated potential is identified as a likely mechanism behind the loss of inner oxide chromium. It is suggested that the loss of inner-oxide chromium leads to a less protective inner oxide, and a higher rate of oxide dissolution. Sample areas that were not irradiated, but were exposed to the flow of radiolyzed water, exhibited most of the same phenomena found on irradiated areas including loss of Cr and thinner more porous oxides, indicating that water radiolysis is the primary mechanism. When a sample with a pre-formed oxide was irradiated in the same conditions, the region exposed to radiolyzed

  7. The morphological changes of Ascaris lumbricoides ova in sewage sludge water treated by gamma irradiation

    NASA Astrophysics Data System (ADS)

    Shamma, M.; Al-Adawi, M. A.

    2002-10-01

    Untreated wastewater sampled from Damascus sewage water treatment plant containing nematode Ascaris lumbricoides ova were treated using gamma irradiation (doses between 1.5 and 8 kGy), immediately after irradiation the morphological and developmental status of eggs was examined microscopically. Major morphological changes of the contents of the eggs were detected. These eggs were incubated for 8 weeks, after this period no larvae "inside the eggs" were observed. Thus the morphological changes can be used as a viable parameter.

  8. Effects of gas flow on oxidation reaction in liquid induced by He/O{sub 2} plasma-jet irradiation

    SciTech Connect

    Nakajima, Atsushi; Uchida, Giichiro Takenaka, Kosuke; Setsuhara, Yuichi; Kawasaki, Toshiyuki; Koga, Kazunori; Sarinont, Thapanut; Amano, Takaaki; Shiratani, Masaharu

    2015-07-28

    We present here analysis of oxidation reaction in liquid by a plasma-jet irradiation under various gas flow patterns such as laminar and turbulence flows. To estimate the total amount of oxidation reaction induced by reactive oxygen species (ROS) in liquid, we employ a KI-starch solution system, where the absorbance of the KI-starch solution near 600 nm behaves linear to the total amount of oxidation reaction in liquid. The laminar flow with higher gas velocity induces an increase in the ROS distribution area on the liquid surface, which results in a large amount of oxidation reaction in liquid. However, a much faster gas flow conversely results in a reduction in the total amount of oxidation reaction in liquid under the following two conditions: first condition is that the turbulence flow is triggered in a gas flow channel at a high Reynolds number of gas flow, which leads to a marked change of the spatial distribution of the ROS concentration in gas phase. Second condition is that the dimpled liquid surface is formed by strong gas flow, which prevents the ROS from being transported in radial direction along the liquid surface.

  9. Luminescence imaging of water during proton-beam irradiation for range estimation

    SciTech Connect

    Yamamoto, Seiichi Okumura, Satoshi; Komori, Masataka; Toshito, Toshiyuki

    2015-11-15

    Purpose: Proton therapy has the ability to selectively deliver a dose to the target tumor, so the dose distribution should be accurately measured by a precise and efficient method. The authors found that luminescence was emitted from water during proton irradiation and conjectured that this phenomenon could be used for estimating the dose distribution. Methods: To achieve more accurate dose distribution, the authors set water phantoms on a table with a spot scanning proton therapy system and measured the luminescence images of these phantoms with a high-sensitivity, cooled charge coupled device camera during proton-beam irradiation. The authors imaged the phantoms of pure water, fluorescein solution, and an acrylic block. Results: The luminescence images of water phantoms taken during proton-beam irradiation showed clear Bragg peaks, and the measured proton ranges from the images were almost the same as those obtained with an ionization chamber. Furthermore, the image of the pure-water phantom showed almost the same distribution as the tap-water phantom, indicating that the luminescence image was not related to impurities in the water. The luminescence image of the fluorescein solution had ∼3 times higher intensity than water, with the same proton range as that of water. The luminescence image of the acrylic phantom had a 14.5% shorter proton range than that of water; the proton range in the acrylic phantom generally matched the calculated value. The luminescence images of the tap-water phantom during proton irradiation could be obtained in less than 2 s. Conclusions: Luminescence imaging during proton-beam irradiation is promising as an effective method for range estimation in proton therapy.

  10. Ion-beam-irradiated CYTOP-transferred graphene for liquid crystal cells

    NASA Astrophysics Data System (ADS)

    Oh, Jeong Hyeon; Choi, Gyu Jin; Kwon, Ki Chang; Bae, Sa-Rang; Jang, Ho Won; Gwag, Jin Seog; Kim, Soo Young

    2017-05-01

    The twisted nematic liquid crystal cell was developed by using a CYTOP-transferred graphene sheet as an electrode and an alignment layer. A graphene layer was synthesized by chemical vapor deposition and transferred onto a plastic substrate using a fluoropolymer known as CYTOP. As the ion-beam treatment time increased, the sheet resistance increased from 500 to 1100 Ω/sq., while the water contact angle decreased from 110.5° to 69.7°. The increased intensities of the D and G' bands and the appearance of D + D″ and D + G' bands in the Raman spectra indicated the formation of defects because of the ion-beam treatment. An ion-beam exposure time of 15 s was found to be the most effective for the production of CYTOP-transferred graphene and for achieving high contrast in operating cells. The ion beam detached F from the CYTOP-transferred graphene layer, and the resulting exposure of the C=C bond on the graphene surface affected the alignment of liquid crystal molecules. Based on these results, the technique described here has applications in novel, high-performance liquid crystal displays that do not require indium-tin-oxide electrodes and polyimide alignment layers. Sheets synthesized by chemical vapor deposition were transferred and simultaneously doped using fluoropolymer supporting layers. [Figure not available: see fulltext.

  11. On the Stability of Liquid Water on Present Day Mars

    NASA Technical Reports Server (NTRS)

    Haberle, Robert M.; DeVincenzi, Donald L. (Technical Monitor)

    2000-01-01

    The mean annual surface pressure and temperature on present day Mars do not allow for the long term stability of liquid water on the surface. However, theoretical arguments have been advanced that suggest liquid water could form in transient events even though it would not be in equilibrium with the environment. Using a Mars General Circulation Model, we calculate where and for how long the surface pressure and surface temperature meet the minimum requirements for this metastability of liquid water. These requirements are that the pressure and temperature must be above the triple point of water, but below its boiling point. We find that there are five regions on Mars where these requirements are periodically satisfied: in the near equatorial regions of Amazonis, Arabia, and Elysium, and in the Hellas and Argyre impact basins. Whether liquid water ever forms in these regions depends on the availability of ice and heat, and on the evaporation rate. The latter is poorly understood for low pressure CO2 environments, but is likely to be so high that melting occurs rarely, if at all. However, in the relatively recent past, surface pressures may have been higher than they are today perhaps by as much as a factor of 2 or 3. Under these circumstances melting would have been easier to achieve. We plan to undertake laboratory experiments to better understand the potential for melting in low pressure environments.

  12. Development of a dispersive liquid-liquid microextraction method using a lighter-than-water ionic liquid for the analysis of polycyclic aromatic hydrocarbons in water.

    PubMed

    Medina, Giselle S; Reta, Mario

    2016-11-01

    A dispersive liquid-liquid microextraction method using a lighter-than-water phosphonium-based ionic liquid for the extraction of 16 polycyclic aromatic hydrocarbons from water samples has been developed. The extracted compounds were analyzed by liquid chromatography coupled to fluorescence/diode array detectors. The effects of several experimental parameters on the extraction efficiency, such as type and volume of ionic liquid and disperser solvent, type and concentration of salt in the aqueous phase and extraction time, were investigated and optimized. Three phosphonium-based ionic liquids were assayed, obtaining larger extraction efficiencies when trihexyl-(tetradecyl)phosphonium bromide was used. The optimized methodology requires a few microliters of a lighter-than-water phosphonium-based ionic liquid, which allows an easy separation of the extraction solvent phase. The obtained limits of detection were between 0.02 and 0.56 μg/L, enrichment factors between 109 and 228, recoveries between 60 and 108%, trueness between 0.4 and 9.9% and reproducibility values between 3 and 12% were obtained. These figures of merit combined with the simplicity, rapidity and low cost of the analytical methodology indicate that this is a viable and convenient alternative to the methods reported in the literature. The developed method was used to analyze polycyclic aromatic hydrocarbons in river water samples.

  13. On the Fluctuations that Order and Frustrate Liquid Water

    NASA Astrophysics Data System (ADS)

    Limmer, David Tyler

    At ambient conditions, water sits close to phase coexistence with its crystal. More so than in many other materials, this fact is manifested in the fluctuations that maintain a large degree of local order in the liquid. These fluctuations and how they result in long-ranged order, or its absence, are emergent features of many interacting molecules. Their study therefore requires using the tools of statistical mechanics for their their systematic understanding. In this dissertation we develop such an understanding. In particular, we focus on collective behavior that emerges in liquid and solid water. At room temperatures, the thermophysical properties of water are quantified and rationalized with simple molecular models. A key feature of these models is the correct characterization of the competition between entropic forces of packing and the energetic preference for tetrahedral order. At cold temperatures, the properties of ice surfaces are studied with statistical field theory. The theory we develop for the long wavelength features of ice interfaces allows us to explain the existence of a premelting layer on the surface of ice and the stability of ice in confinement. In between these extremes, the dynamics of supercooled water are considered. A detailed theory for the early stages of coarsening is developed and used to explain the peculiar observation of a transient second liquid state of water. When coarsening dynamics are arrested, the result is the formation of a glassy states of water. We show that out-of-equilibrium the phase diagram for supercooled water exhibits a rich amount of structure, including a triple point between two glass phases of water and the liquid. At the end, we explore possible technological implications for the interplay between ordering and frustration in studies of water at metal interfaces.

  14. Simple Evaluation Method of Atmospheric Plasma Irradiation Dose using pH of Water

    NASA Astrophysics Data System (ADS)

    Koga, Kazunori; Sarinont, Thapanut; Amano, Takaaki; Seo, Hyunwoong; Itagaki, Naho; Nakatsu, Yoshimichi; Tanaka, Akiyo; Shiratani, Masaharu

    2015-09-01

    Atmospheric discharge plasmas are promising for agricultural productivity improvements and novel medical therapies, because plasma provides high flux of short-lifetime reactive species at low temperature, leading to low damage to living body. For the plasma-bio applications, various kinds of plasma systems are employed, thus common evaluation methods are needed to compare plasma irradiation dose quantitatively among the systems. Here we offer simple evaluation method of plasma irradiation dose using pH of water. Experiments were carried out with a scalable DBD device. 300 μl of deionized water was prepared into the quartz 96 microwell plate at 3 mm below electrode. The pH value has been measured just after 10 minutes irradiation. The pH value was evaluated as a function of plasma irradiation dose. Atmospheric air plasma irradiation decreases pH of water with increasing the dose. We also measured concentrations of chemical species such as nitrites, nitrates and H2O2. The results indicate our method is promising to evaluate plasma irradiation dose quantitatively.

  15. A numerical model of initial recombination for high-LET irradiation: Application to liquid-filled ionization chambers

    NASA Astrophysics Data System (ADS)

    Aguiar, P.; Pardo-Montero, J.

    2016-02-01

    In this paper we present a numerical model of initial recombination in media irradiated with high linear energy transfer (LET) ions, which relies on an amorphous track model of ionization of high LET particles, and diffusion, drift and recombination of ionized charge carriers. The model has fundamental applications for the study of recombination in non-polar liquids, as well as practical ones, like in modelling hadrontherapy dosimetry with ionization chambers. We have used it to study the response of liquid-filled ionization chambers to hadrontherapy beams: dependence of initial recombination on ion species, energy and applied external electric field.

  16. Ionic liquid as a promising biobased green solvent in combination with microwave irradiation for direct biodiesel production.

    PubMed

    Wahidin, Suzana; Idris, Ani; Shaleh, Sitti Raehanah Muhamad

    2016-04-01

    The wet biomass microalgae of Nannochloropsis sp. was converted to biodiesel using direct transesterification (DT) by microwave technique and ionic liquid (IL) as the green solvent. Three different ionic liquids; 1-butyl-3-metyhlimidazolium chloride ([BMIM][Cl], 1-ethyl-3-methylimmidazolium methyl sulphate [EMIM][MeSO4] and 1-butyl-3-methylimidazolium trifluoromethane sulfonate [BMIM][CF3SO3]) and organic solvents (hexane and methanol) were used as co-solvents under microwave irradiation and their performances in terms of percentage disruption, cell walls ruptured and biodiesel yields were compared at different reaction times (5, 10 and 15 min). [EMIM][MeSO4] showed highest percentage cell disruption (99.73%) and biodiesel yield (36.79% per dried biomass) after 15 min of simultaneous reaction. The results demonstrated that simultaneous extraction-transesterification using ILs and microwave irradiation is a potential alternative method for biodiesel production.

  17. Residual water in ionic liquids: clustered or dissociated?

    PubMed

    Reid, Joshua E S J; Walker, Adam J; Shimizu, Seishi

    2015-06-14

    How do residual water molecules in ionic liquids (ILs) interact with themselves, as well as with the ions? This question is crucial in understanding why the physical properties of ILs--and chemical reactions performed in them--are strongly affected by the residual water content. There have been three conflicting hypotheses regarding the structure and behaviour of the residual water: (i) water molecules are separated from one another, while interacting strongly with the ions, and dispersed throughout the medium; (ii) water molecules self-associate or form clusters in the ILs; (iii) residual water weakens ion-ion interactions. A satisfactory resolution of these conflicting suggestions has been hindered by the complexity and long range of the interactions in the water-IL mixture and by the often profound differences in physical structure between various different ILs. Here we present a route to resolve this question through a combination of a statistical thermodynamic theory (Kirkwood-Buff theory) with density and osmotic data from the literature. The structure of water-IL mixtures is shown to be water content dependent; at the lowest measured water concentration, strong water-IL interaction and water-water separation are observed in accordance to (i), whereas water in a more hydrophobic IL environment seems to self-associate at moderately low water concentrations, in accordance with (ii).

  18. Heat and Momentum Transfer on the Rapid Phase Change of Liquid Induced by Nanosecond-Pulsed Laser Irradiation.

    NASA Astrophysics Data System (ADS)

    Park, Hee Kuwon

    1994-01-01

    This study examines the physics of the liquid -vapor phase transition phenomenon induced by nanosecond -pulsed ultraviolet laser irradiation. This work is concerned with the science and technological applications of the phenomenon of rapid nucleation and explosive vaporization of a liquid in contact with a pulsed-laser heated solid surface. The thermodynamics of the phase transition, the kinetics of collective bubble growth and collapse, and the transient development of pressure field have been investigated experimentally by various fast optical sensing techniques. The purpose of this study is to provide new insight into the physics of the liquid-vapor transition and the interaction between laser and liquid-solid interface. A detailed study on the practical aspects of a novel technological application, the laser cleaning technology, is also included. A model system investigated throughout this work is pure water, methanol, or isopropanol in contact with a solid chromium surface that is heated by ultraviolet KrF excimer laser pulses of nanosecond duration. The dynamics of bubble nucleation, growth, and collapse is studied by optical specular reflectance and scattering probe, which isolates the onset of phase transformation with great accuracy. The thermodynamics of phase transition and metastability of liquid matter have been studied by transient photothermal reflectance probe, which monitors the transient temperature field non-intrusively with nanosecond time resolution. The transient response from the photothermal reflectance probe which utilizes temperature-dependent optical properties of an embedded thin film sensor are coupled with heat transfer modeling results in order to predict the thermodynamic condition for the vaporization in nanosecond time scale. The generation of transient pressure pulses by bubble growth and the effect of static pressure on the phase transition are studied by the piezoelectric transducer probe, photoacoustic probe beam deflection

  19. The irradiation of rabbit sperm cells with He-Ne laser prevents their in vitro liquid storage dependent damage.

    PubMed

    Iaffaldano, Nicolaia; Rosato, Maria Pina; Paventi, Gianluca; Pizzuto, Roberto; Gambacorta, Mario; Manchisi, Angelo; Passarella, Salvatore

    2010-05-01

    The aim of the study was to investigate the effects of different energy doses of helium-neon (He-Ne) laser irradiation on both mitochondrial bioenergetics functions and functional quality of rabbit spermatozoa during 48 h of in vitro liquid storage at 15 degrees C. 11 rabbit semen pools were each divided into four aliquots: three of them were irradiated with He-Ne laser with different energy doses (3.96, 6.12 and 9.00 J/cm(2)) being the last control kept under the same experimental conditions without irradiation. Sperm motility, viability and acrosome integrity were monitored together with cytochrome c oxidase (COX) activity and the cell energy charge (EC) at 0, 24 and 48 h of storage. Irradiated samples stored for 24 and 48 h better maintained motility (P < 0.01), acrosome integrity (P < 0.01) and viability (P < 0.05) with respect to the control, particularly with the energy dose of 6.12 J/cm(2) that showed the most intense biostimulative effect. COX activity and EC were immediately increased by irradiation particularly in the treatments 6.12 and 9.00 J/cm(2) (P < 0.05), that maintained their levels higher with respect to the control after 48 h of storage (P < 0.01). COX activity of rabbit sperm cells was positively correlated with EC (P < 0.05), viability (P < 0.01) and acrosome integrity (P < 0.05) parameters. These results indicate that the effects of He-Ne laser irradiation on sperm cells are mediated through the stimulation of the sperm mitochondrial respiratory chain and that this effect plays a significant role in the augmentation of the rabbit sperm cells' capability to survive during liquid storage conditions.

  20. An eight-month climatology of marine stratocumulus cloud fraction, albedo, and integrated liquid water

    NASA Technical Reports Server (NTRS)

    Fairall, C. W.; Hare, J. E.; Snider, Jack B.

    1990-01-01

    As part of the FIRE/Extended Time Observations (ETO) program, extended time observations were made at San Nicolas Island (SNI) from March to October, 1987. Hourly averages of air temperature, relative humidity, wind speed and direction, solar irradiance, and downward longwave irradiance were recorded. The radiation sensors were standard Eppley pyranometers (shortwave) and pyrgeometers (longwave). The SNI data were processed in several ways to deduce properties of the stratocumulus covered marine boundary layer (MBL). For example, from the temperature and humidity the lifting condensation level, which is an estimate of the height of the cloud bottom, can be computed. A combination of longwave irradiance statistics can be used to estimate fractional cloud cover. An analysis technique used to estimate the integrated cloud liquid water content (W) and the cloud albedo from the measured solar irradiance is also described. In this approach, the cloud transmittance is computed by dividing the irradiance measured at some time by a clear sky value obtained at the same hour on a cloudless day. From the transmittance and the zenith angle, values of cloud albedo and W are computed using the radiative transfer parameterizations of Stephens (1978). These analysis algorithms were evaluated with 17 days of simultaneous and colocated mm-wave (20.6 and 31.65 GHz) radiometer measurements of W and lidar ceilometer measurements of cloud fraction and cloudbase height made during the FIRE IFO. The algorithms are then applied to the entire data set to produce a climatology of these cloud properties for the eight month period.

  1. Economics of liquid hydrogen from water electrolysis

    NASA Technical Reports Server (NTRS)

    Lin, F. N.; Moore, W. I.; Walker, S. W.

    1985-01-01

    An economical model for preliminary analysis of LH2 cost from water electrolysis is presented. The model is based on data from vendors and open literature, and is suitable for computer analysis of different scenarios for 'directional' purposes. Cost data associated with a production rate of 10,886 kg/day are presented. With minimum modification, the model can also be used to predict LH2 cost from any electrolyzer once the electrolyzer's cost data are available.

  2. Economics of liquid hydrogen from water electrolysis

    NASA Technical Reports Server (NTRS)

    Lin, F. N.; Moore, W. I.; Walker, S. W.

    1985-01-01

    An economical model for preliminary analysis of LH2 cost from water electrolysis is presented. The model is based on data from vendors and open literature, and is suitable for computer analysis of different scenarios for 'directional' purposes. Cost data associated with a production rate of 10,886 kg/day are presented. With minimum modification, the model can also be used to predict LH2 cost from any electrolyzer once the electrolyzer's cost data are available.

  3. Satellite Remote Sensing of the Liquid Water Sensitivity in Water Clouds

    NASA Technical Reports Server (NTRS)

    Han, Qing-Yuan; Rossow, William B.; Welch, Ronald; Zeng, Jane; Jansen, James E. (Technical Monitor)

    2001-01-01

    In estimation of the aerosol indirect effect, cloud liquid water path is considered either constant (Twomey effect) or increasing with enhanced droplet number concentrations (drizzle-suppression effect, or Albrecht effect) if cloud microphysics is the prevailing mechanism during the aerosol-cloud interactions. On the other hand, if cloud thermodynamics and dynamics are considered, the cloud liquid water path may be decreased with increasing droplet number concentration, which is predicted by model calculations and observed in ship-track and urban influence studies. This study is to examine the different responses of cloud liquid water path to changes of cloud droplet number concentration. Satellite data (January, April, July and October 1987) are used to retrieve the cloud liquid water sensitivity, defined as the changes of liquid water path versus changes of column droplet number concentrations. The results of a global survey reveal that 1) in at least one third of the cases the cloud liquid water sensitivity is negative, and the regional and seasonal variations of the negative liquid water sensitivity are consistent with other observations; 2) cloud droplet sizes are always inversely proportional to column droplet number concentrations. Our results suggest that an increase of cloud droplet number concentration leads to reduced cloud droplet size and enhanced evaporation, which weakens the coupling between water clouds and boundary layer in warm zones, decreases water supply from surface and desiccates cloud liquid water. Our results also suggest that the current evaluations of negative aerosol indirect forcing by global climate models (GCM), which are based on Twomey effect or Albrecht effect, may be overestimated.

  4. Disinfection of contaminated water by using solar irradiation.

    PubMed

    Caslake, Laurie F; Connolly, Daniel J; Menon, Vilas; Duncanson, Catriona M; Rojas, Ricardo; Tavakoli, Javad

    2004-02-01

    Contaminated water causes an estimated 6 to 60 billion cases of gastrointestinal illness annually. The majority of these cases occur in rural areas of developing nations where the water supply remains polluted and adequate sanitation is unavailable. A portable, low-cost, and low-maintenance solar unit to disinfect unpotable water has been designed and tested. The solar disinfection unit was tested with both river water and partially processed water from two wastewater treatment plants. In less than 30 min in midday sunlight, the unit eradicated more than 4 log10 U (99.99%) of bacteria contained in highly contaminated water samples. The solar disinfection unit has been field tested by Centro Panamericano de Ingenieria Sanitaria y Ciencias del Ambiente in Lima, Peru. At moderate light intensity, the solar disinfection unit was capable of reducing the bacterial load in a controlled contaminated water sample by 4 log10 U and disinfected approximately 1 liter of water in 30 min.

  5. Disinfection of Contaminated Water by Using Solar Irradiation

    PubMed Central

    Caslake, Laurie F.; Connolly, Daniel J.; Menon, Vilas; Duncanson, Catriona M.; Rojas, Ricardo; Tavakoli, Javad

    2004-01-01

    Contaminated water causes an estimated 6 to 60 billion cases of gastrointestinal illness annually. The majority of these cases occur in rural areas of developing nations where the water supply remains polluted and adequate sanitation is unavailable. A portable, low-cost, and low-maintenance solar unit to disinfect unpotable water has been designed and tested. The solar disinfection unit was tested with both river water and partially processed water from two wastewater treatment plants. In less than 30 min in midday sunlight, the unit eradicated more than 4 log10 U (99.99%) of bacteria contained in highly contaminated water samples. The solar disinfection unit has been field tested by Centro Panamericano de Ingenieria Sanitaria y Ciencias del Ambiente in Lima, Peru. At moderate light intensity, the solar disinfection unit was capable of reducing the bacterial load in a controlled contaminated water sample by 4 log10 U and disinfected approximately 1 liter of water in 30 min. PMID:14766599

  6. Liquid-liquid interfaces of semifluorinated alkane diblock copolymers with water, alkanes, and perfluorinated alkanes.

    PubMed

    Pierce, Flint; Tsige, Mesfin; Perahia, Dvora; Grest, Gary S

    2008-12-18

    The liquid-liquid interface between semifluorinated alkane diblock copolymers of the form F3C(CF2)n-1-(CH2)m-1CH3 and water, protonated alkanes, and perfluorinated alkanes are studied by fully atomistic molecular dynamics simulations. A modified version of the OPLS-AA (Optimized Parameter for Liquid Simulation All-Atom) force field of Jorgensen et al. has been used to study the interfacial behavior of semifluorinated diblocks. Aqueous interfaces are found to be sharp, with correspondingly large values of the interfacial tension. Due to the reduced hydrophobicity of the protonated block compared to the fluorinated block, hydrogen enhancement is observed at the interface. Water dipoles in the interfacial region are found to be oriented nearly parallel to the liquid-liquid interface. A number of protonated alkanes and perfluorinated alkanes are found to be mutually miscible with the semifluorinated diblocks. For these liquids, interdiffusion follows the expected Fickian behavior, and concentration-dependent diffusivities are determined.

  7. Liquid-liquid interfaces of semifluorinated alkane diblock copolymers with water, alkanes, and perfluorinated alkanes.

    SciTech Connect

    Perahia, Dvora, Dr.; Pierce, Flint; Tsige, Mesfin; Grest, Gary Stephen, Dr.

    2008-08-01

    The liquid-liquid interface between semifluorinated alkane diblock copolymers of the form F3C(CF2)n-1-(CH2)m-1CH3 and water, protonated alkanes, and perfluorinated alkanes are studied by fully atomistic molecular dynamics simulations. A modified version of the OPLS-AA (Optimized Parameter for Liquid Simulation All-Atom) force field of Jorgensen et al. has been used to study the interfacial behavior of semifluorinated diblocks. Aqueous interfaces are found to be sharp, with correspondingly large values of the interfacial tension. Due to the reduced hydrophobicity of the protonated block compared to the fluorinated block, hydrogen enhancement is observed at the interface. Water dipoles in the interfacial region are found to be oriented nearly parallel to the liquid-liquid interface. A number of protonated alkanes and perfluorinated alkanes are found to be mutually miscible with the semifluorinated diblocks. For these liquids, interdiffusion follows the expected Fickian behavior, and concentration-dependent diffusivities are determined.

  8. Limiting shear stress and monotonic properties of liquid water

    NASA Astrophysics Data System (ADS)

    Gorshkov, A. I.

    2016-12-01

    Publications in scientific journals in which the authors attempt to experimentally prove that water, the most widespread substance on the Earth, is not a completely classical liquid, have become more frequent recently. This means, first, that water behaves as a solid at very low shear stress, i.e., does not flow, and, second, that the temperature dependences of its different properties are non-monotonic, i.e., possess singularities. We are aware of several such publications [1-5].

  9. Molecular dynamics simulation of liquid water: Hybrid density functionals

    SciTech Connect

    Todorova, T; Seitsonen, A; Hutter, J; Kuo, W; Mundy, C

    2005-09-12

    The structure, dynamical and electronic properties of liquid water utilizing different hybrid density functionals were tested within the plane wave framework of first principles molecular dynamics simulations. The computational approach, which employs modified functionals with short-ranged Hartree-Fock exchange, was first tested in calculations of the structural and bonding properties of the water dimer and cyclic water trimer. Liquid water simulations were performed at the state point of 350 K at the experimental density. Simulations included three different hybrid functionals, a meta functional, four gradient corrected functionals, the local density and Hartree-Fock approximation. It is found that hybrid functionals are superior in reproducing the experimental structure and dynamical properties as measured by the radial distribution function and self diffusion constant when compared to the pure density functionals. The local density and Hartree-Fock approximations show strongly over- and under-structured liquids, respectively. Hydrogen bond analysis shows that the hybrid functionals give slightly smaller averaged numbers of hydrogen bonds and similar hydrogen bond populations as pure density functionals. The average molecular dipole moments in the liquid from the three hybrid functionals are lower than from the corresponding pure density functionals.

  10. Molecular dynamics of the water liquid-vapor interface

    NASA Technical Reports Server (NTRS)

    Wilson, M. A.; Pohorille, A.; Pratt, L. R.; MacElroy, R. D. (Principal Investigator)

    1987-01-01

    The results of molecular dynamics calculations on the equilibrium interface between liquid water and its vapor at 325 K are presented. For the TIP4P model of water intermolecular pair potentials, the average surface dipole density points from the vapor to the liquid. The most common orientations of water molecules have the C2 nu molecular axis roughly parallel to the interface. The distributions are quite broad and therefore compatible with the intermolecular correlations characteristic of bulk liquid water. All near-neighbor pairs in the outermost interfacial layers are hydrogen bonded according to the common definition adopted here. The orientational preferences of water molecules near a free surface differ from those near rigidly planar walls which can be interpreted in terms of patterns found in hexagonal ice 1. The mean electric field in the interfacial region is parallel to the mean polarization which indicates that attention cannot be limited to dipolar charge distributions in macroscopic descriptions of the electrical properties of this interface. The value of the surface tension obtained is 132 +/- 46 dyn/cm, significantly different from the value for experimental water of 68 dyn/cm at 325 K.

  11. Molecular dynamics of the water liquid-vapor interface

    NASA Technical Reports Server (NTRS)

    Wilson, M. A.; Pohorille, A.; Pratt, L. R.; MacElroy, R. D. (Principal Investigator)

    1987-01-01

    The results of molecular dynamics calculations on the equilibrium interface between liquid water and its vapor at 325 K are presented. For the TIP4P model of water intermolecular pair potentials, the average surface dipole density points from the vapor to the liquid. The most common orientations of water molecules have the C2 nu molecular axis roughly parallel to the interface. The distributions are quite broad and therefore compatible with the intermolecular correlations characteristic of bulk liquid water. All near-neighbor pairs in the outermost interfacial layers are hydrogen bonded according to the common definition adopted here. The orientational preferences of water molecules near a free surface differ from those near rigidly planar walls which can be interpreted in terms of patterns found in hexagonal ice 1. The mean electric field in the interfacial region is parallel to the mean polarization which indicates that attention cannot be limited to dipolar charge distributions in macroscopic descriptions of the electrical properties of this interface. The value of the surface tension obtained is 132 +/- 46 dyn/cm, significantly different from the value for experimental water of 68 dyn/cm at 325 K.

  12. Breakdown Voltage Scaling in Gas Bubbles Immersed in Liquid Water

    NASA Astrophysics Data System (ADS)

    Gucker, Sarah; Sommers, Bradley; Foster, John

    2013-09-01

    Radicals produced by the interaction of plasma with liquid water have the capacity to rapidly oxidize organic contaminants. This interaction is currently being investigated as a means to purify water. Direct plasma creation in water typically requires very high voltages to achieve breakdown. Igniting plasma in individual gas bubbles in liquid water on the other hand requires much less voltage. Furthermore, the use of an electrode-less plasma initiation in such bubbles is attractive in that it eliminates electrode erosion thereby circumventing the contamination issue. The breakdown physics of isolated bubbles in liquid water is still poorly understood. In this work, we investigate the relationship between applied voltage for breakdown and the associated pd. This is achieved by locating the breakdown voltage over a range of bubble sizes. This approach allows for the generation of a Paschen-type breakdown curve for isolated bubbles. Such a relationship yields insight into breakdown mechanics and even streamer propagation through water. This material is based upon work supported by the National Science Foundation (CBET 1033141) and the National Science Foundation Graduate Student Research Fellowship under Grant No. DGE 0718128.

  13. Accelerated corrosion and oxide dissolution in 316L stainless steel irradiated in situ in high temperature water

    NASA Astrophysics Data System (ADS)

    Raiman, Stephen S.; Was, Gary S.

    2017-09-01

    316L stainless steel samples were irradiated with a proton beam while simultaneously exposed to high temperature water with added hydrogen (320 °C, 3 wppm H2, neutral pH) to study the effect of radiation on stainless steel corrosion. Irradiated samples had thinner and more porous inner oxides with a lower chromium content when compared to unirradiated samples. Observations suggest that depletion of chromium from the inner oxide can be attributed to the dissolution of chromium-rich spinel oxides in irradiated water, leading to an accelerated rate of inner oxide dissolution. Sample areas which were not irradiated, but were exposed to the flow of irradiated water were also found to be porous and deficient in chromium, indicating that these phenomena can be attributed primarily to water radiolysis. A new empirical equation for oxide growth and dissolution is used to describe the observed changes in oxide thickness under irradiation. An experiment in which a stainless steel sample was exposed to high temperature water (320 °C, 3 wppm H2, neutral pH) without irradiation, and then exposed for a second time with irradiation was conducted to observe the effect of irradiation on a pre-formed protective film. After the irradiated exposure, the sample exhibited chromium loss in regions which were directly irradiated, but not on regions exposed only to irradiated water, suggesting that a pre-formed protective oxide may be effective in preventing chromium loss due to irradiated water. Additionally, this observation suggests that enhanced kinetics under irradiation may have accelerated dissolution of chromium from the inner oxide.

  14. Computer simulation of liquid/liquid interfaces. I. Theory and application to octane/water

    NASA Astrophysics Data System (ADS)

    Zhang, Yuhong; Feller, Scott E.; Brooks, Bernard R.; Pastor, Richard W.

    1995-12-01

    Statistical ensembles for simulating liquid interfaces at constant pressure and/or surface tension are examined, and equations of motion for molecular dynamics are obtained by various extensions of the Andersen extended system approach. Valid ensembles include: constant normal pressure and surface area; constant tangential pressure and length normal to the interface; constant volume and surface tension; and constant normal pressure and surface tension. Simulations at 293 K and 1 atm normal pressure show consistent results with each other and with a simulation carried out at constant volume and energy. Calculated surface tensions for octane/water (61.5 dyn/cm), octane/vacuum (20.4 dyn/cm) and water/vacuum (70.2 dyn/cm) are in very good agreement with experiment (51.6, 21.7, and 72.8 dyn/cm, respectively). The practical consequences of simulating with two other approaches commonly used for isotropic systems are demonstrated on octane/water: applying equal normal and tangential pressures leads to an instability; and applying a constant isotropic pressure of 1 atm leads to a large positive normal pressure. Both results are expected for a system of nonzero surface tension. Mass density and water polarization profiles in the liquid/liquid and liquid/vapor interfaces are also compared.

  15. Switchable water: microfluidic investigation of liquid-liquid phase separation mediated by carbon dioxide.

    PubMed

    Lestari, Gabriella; Abolhasani, Milad; Bennett, Darla; Chase, Preston; Günther, Axel; Kumacheva, Eugenia

    2014-08-27

    Increase in the ionic strength of water that is mediated by the reaction of carbon dioxide (CO2) with nitrogenous bases is a promising approach toward phase separation in mixtures of water with organic solvents and potentially water purification. Conventional macroscale studies of this complicated process are challenging, due to its occurrence via several consecutive and concurrent steps, mass transfer limitation, and lack of control over gas-liquid interfaces. We report a new microfluidic strategy for fundamental studies of liquid-liquid phase separation mediated by CO2 as well as screening of the efficiency of nitrogenous agents. A single set of microfluidic experiments provided qualitative and quantitative information on the kinetics and completeness of water-tetrahydrofuran phase separation, the minimum amount of CO2 required to complete phase separation, the total CO2 uptake, and the rate of CO2 consumption by the liquid mixture. The efficiency of tertiary diamines with different lengths of alkyl chain was examined in a time- and labor-efficient manner and characterized with the proposed efficiency parameter. A wealth of information obtained using the MF methodology can facilitate the development of new additives for switchable solvents in green chemistry applications.

  16. Boson peak, Ioffe-Regel Crossover, and Liquid-Liquid phase transition in Supercooled Water

    NASA Astrophysics Data System (ADS)

    Kumar, Pradeep

    We have investigated the onset of Boson peak in a model of liquid water which exhibits a clear first-order phase transition between a low-density liquid phase and a high-density liquid phase of water at low temperature and high pressure. We find that the at low pressures, the onset of Boson peak coincides with the Widom-line of the system. At high pressures, the onset occurs at the transition temperature between the two liquids. Furthermore, we show that at both low and high pressure, the frequency of the Boson peak coincides with the Ioffe-Regel crossover of the transverse phonons, suggesting that the breakdown of Debye behavior is a general feature of Ioffe-Regel limit crossover in supercooled water. The frequency of the Boson peak is weakly pressure dependent and decreases with increasing pressure. Our work bridges gap between the experimental results on the Boson peak nanoconfined water and the behavior that one would expect from a bulk system.

  17. Solar light irradiation significantly reduced cytotoxicity and disinfection byproducts in chlorinated reclaimed water.

    PubMed

    Lv, Xiao-Tong; Zhang, Xue; Du, Ye; Wu, Qian-Yuan; Lu, Yun; Hu, Hong-Ying

    2017-08-26

    Chlorinated reclaimed water is widely used for landscaping and recreational purposes, resulting in human exposure to toxic disinfection byproducts. Although the quality of chlorinated reclaimed water might be affected by sunlight during storage, the effects of solar light irradiation on the toxicity remain unknown. This study investigated the changes in cytotoxicity and total organic halogen (TOX) of chlorinated reclaimed water exposed to solar light. Irradiation with solar light for 12 h was found to significantly reduce the cytotoxicity of chlorinated reclaimed water by about 75%, with ultraviolet light being responsible for the majority of this reduction. Chlorine residual in reclaimed water tended to increase the cytotoxicity, and the synergy between solar light and free chlorine could not enhance the reduction of cytotoxicity. Adding hydroxyl radical scavengers revealed that the contribution of hydroxyl radical to cytotoxicity reduction was limited. Solar light irradiation concurrently reduced TOX. The low molecular weight (<1 kDa) fraction was the major contributor of cytotoxicity and TOX in chlorinated reclaimed water. Detoxification of the low molecular weight fraction by light irradiation was mainly a result of TOX dehalogenation, while detoxification of the high molecular weight (>1 kDa) fraction was probably caused by photoconversion from high toxic TOX to low toxic TOX. Copyright © 2017. Published by Elsevier Ltd.

  18. Ionic liquid-based dispersive liquid-liquid microextraction for sensitive determination of aromatic amines in environmental water.

    PubMed

    Han, Dandan; Yan, Hongyuan; Row, Kyung H

    2011-05-01

    Ionic liquid-based dispersive liquid-liquid microextraction was developed for the extraction and preconcentration of aromatic amine from environmental water. A suitable mixture of extraction solvent (100 μL, 1-butyl-3-methylimidazolium hexafluorophoshate) and dispersive solvent (750 μL, methanol) were injected into the aqueous samples (10.00 mL), forming a cloudy solution. After centrifuging, enriched analytes in the sediment phase were determined by HPLC-UV. The effect of various factors, such as the extraction and dispersive solvent, sample pH, extraction time and salt effect were investigated. Under optimum conditions, enrichment factors for 2-anilinoethanol, o-chloroaniline and 4-bromo-N,N-dimethylaniline were above 50 and the limits of detection (LODs) were 0.023, 0.015 and 0.026 ng/mL, respectively. Their linear ranges were 0.8-400 ng/mL for 2-anilinoethanol, 0.5-200 ng/mL for o-chloroaniline and 0.4-200 ng/mL for 4-bromo-N,N-dimethylaniline, respectively. Relative standard deviations (RSDs) were below 5.0%. The relative recoveries from samples of environmental water were in the range of 82.0-94.0%. Compared with other methods, dispersive liquid-liquid microextraction is simple, rapid, sensitive and economical.

  19. Effects of water-filtered infrared A irradiation on human fibroblasts.

    PubMed

    Jung, Tobias; Höhn, Annika; Piazena, Helmut; Grune, Tilman

    2010-01-01

    Infrared radiation is a substantial part of the solar energy output reaching the earth surface. Therefore, exposure of humans to infrared radiation is common. However, whether and how infrared (IR) or infrared A acts on human skin cells is still under debate. Recently the generation of reactive oxygen species by water-filtered infrared A (wIRA) irradiation was postulated. wIRA shows a spectral distribution similar to that of solar irradiation at the earth's surface. Thus, the need for protection of human skin from both solar- and artificially generated infrared A irradiation was concluded. Here we demonstrate that in human dermal fibroblasts this reactive oxygen species generation is dependent on heat formation by infrared A and can be reproduced by thermal exposure. On the other hand wIRA irradiation had no detectable effect if the temperature in the cells was kept constant, even if irradiance exceeded the extraterrestrial solar irradiance in the IR range by a factor of about 4 and the maximum at noontime in the tropics by a factor up to about 6. This could be demonstrated by the measurement of oxidant formation using H(2)DCFDA and the determination of protein carbonyls. In additional experiments we could show that during thermal exposure the mitochondria contribute significantly to oxidant production. Further experiments revealed that the major absorbance of infrared is due to absorption of the energy by cellular water. Copyright 2009 Elsevier Inc. All rights reserved.

  20. Estimating hydroxyl radical photochemical formation rates in natural waters during long-term laboratory irradiation experiments.

    PubMed

    Sun, Luni; Chen, Hongmei; Abdulla, Hussain A; Mopper, Kenneth

    2014-04-01

    In this study it was observed that, during long-term irradiations (>1 day) of natural waters, the methods for measuring hydroxyl radical (˙OH) formation rates based upon sequentially determined cumulative concentrations of photoproducts from probes significantly underestimate actual ˙OH formation rates. Performing a correction using the photodegradation rates of the probe products improves the ˙OH estimation for short term irradiations (<1 day), but not long term irradiations. Only the 'instantaneous' formation rates, which were obtained by adding probes to aliquots at each time point and irradiating these sub-samples for a short time (≤2 h), were found appropriate for accurately estimating ˙OH photochemical formation rates during long-term laboratory irradiation experiments. Our results also showed that in iron- and dissolved organic matter (DOM)-rich water samples, ˙OH appears to be mainly produced from the Fenton reaction initially, but subsequently from other sources possibly from DOM photoreactions. Pathways of ˙OH formation in long-term irradiations in relation to H2O2 and iron concentrations are discussed.

  1. Liquid Water, the ``Most Complex'' Liquid: New Results in Bulk, Nanoconfined, and Biological Environments

    NASA Astrophysics Data System (ADS)

    Stanley, H. Eugene

    2010-03-01

    We will introduce some of the 63 anomalies of the most complex of liquids, water. We will demonstrate some recent progress in understanding these anomalies by combining information provided by recent experiments and simulations on water in bulk, nanoconfined, and biological environments. We will interpret evidence from recent experiments designed to test the hypothesis that liquid water may display ``polymorphism'' in that it can exist in two different phases---and discuss recent work on water's transport anomalies [1] as well as the unusual behavior of water in biological environments [2]. Finally, we will discuss how the general concept of liquid polymorphism [3] is proving useful in understanding anomalies in other liquids, such as silicon, silica, and carbon, as well as metallic glasses, which have in common that they are characterized by two characteristic length scales in their interactions. This work was supported by NSF Chemistry Division, and carried out in collaboration with a number of colleagues, chief among whom are C. A. Angell, M. C. Barbosa, M. C. Bellissent, L. Bosio, F. Bruni, S. V. Buldyrev, M. Canpolat, S. -H. Chen, P. G. Debenedetti, U. Essmann,G. Franzese, A. Geiger, N. Giovambattista, S. Han, P. Kumar, E. La Nave,G. Malescio, F. Mallamace, M. G. Mazza, O. Mishima, P. Netz, P. H. Poole, P. J. Rossky, R. Sadr,S. Sastry, A. Scala, F. Sciortino, A. Skibinsky, F. W. Starr, K. C. Stokely J. Teixeira, L. Xu, and Z. Yan.[4pt] [1] L. Xu, F. Mallamace, Z. Yan, F. W. Starr, S. V. Buldyrev, and H. E. Stanley, ``Appearance of a Fractional Stokes-Einstein Relation in Water and a Structural Interpretation of Its Onset,'' Nature Physics 5, 565--569 (2009). [0pt] [2] P. Kumar, Z. Yan, L. Xu, M. G. Mazza, S. V. Buldyrev, S. -H. Chen. S. Sastry, and H. E. Stanley, ``Glass Transition in Biomolecules and the Liquid-Liquid Critical Point of Water,'' Phys. Rev. Lett. 97, 177802 (2006). [0pt] [3] H. E. Stanley, ed. , Liquid Polymorphism [Advances in Chemical Physics

  2. The interfacial structure of water droplets in a hydrophobic liquid

    PubMed Central

    Smolentsev, Nikolay; Smit, Wilbert J.; Bakker, Huib J.; Roke, Sylvie

    2017-01-01

    Nanoscopic and microscopic water droplets and ice crystals embedded in liquid hydrophobic surroundings are key components of aerosols, rocks, oil fields and the human body. The chemical properties of such droplets critically depend on the interfacial structure of the water droplet. Here we report the surface structure of 200 nm-sized water droplets in mixtures of hydrophobic oils and surfactants as obtained from vibrational sum frequency scattering measurements. The interface of a water droplet shows significantly stronger hydrogen bonds than the air/water or hexane/water interface and previously reported planar liquid hydrophobic/water interfaces at room temperature. The observed spectral difference is similar to that of a planar air/water surface at a temperature that is ∼50 K lower. Supercooling the droplets to 263 K does not change the surface structure. Below the homogeneous ice nucleation temperature, a single vibrational mode is present with a similar mean hydrogen-bond strength as for a planar ice/air interface. PMID:28537259

  3. Complete wetting of Pt(111) by nanoscale liquid water films

    SciTech Connect

    Xu, Yuntao; Dibble, Collin J.; Petrik, Nikolay G.; Smith, R. Scott; Kay, Bruce D.; Kimmel, Gregory A.

    2016-02-04

    The melting and wetting of nanoscale crystalline ice films on Pt(111) that are transiently heated above the melting point using nanosecond laser pulses are studied with infrared refection absorption spectroscopy (IRAS) and Kr temperature programmed desorption (TPD). The as-grown crystalline ice films consist of isolated nanoscale ice crystallites embedded in a hydrophobic water monolayer. Upon heating above the melting point, these ice crystallites rapidly melt to form nanoscale droplets of liquid water. Rapid cooling of the system to cryogenic temperatures after each laser pulse quenches the water films and allows them to be interrogated with IRAS, Kr TPD and other ultrahigh vacuum surface science techniques. With each successive heat pulse, these liquid drops spread across the surface until it is entirely covered with multilayer water films after several pulses. These results, which show that nanoscale water films completely wet Pt(111), are in contrast to molecular dynamics simulations predicting partial wetting of nanoscale water drops on a hydrophobic water monolayer. The results provide valuable new insights into the wetting characteristics of nanoscale water films on a clean, well-characterized single crystal surface.

  4. The interfacial structure of water droplets in a hydrophobic liquid

    NASA Astrophysics Data System (ADS)

    Smolentsev, Nikolay; Smit, Wilbert J.; Bakker, Huib J.; Roke, Sylvie

    2017-05-01

    Nanoscopic and microscopic water droplets and ice crystals embedded in liquid hydrophobic surroundings are key components of aerosols, rocks, oil fields and the human body. The chemical properties of such droplets critically depend on the interfacial structure of the water droplet. Here we report the surface structure of 200 nm-sized water droplets in mixtures of hydrophobic oils and surfactants as obtained from vibrational sum frequency scattering measurements. The interface of a water droplet shows significantly stronger hydrogen bonds than the air/water or hexane/water interface and previously reported planar liquid hydrophobic/water interfaces at room temperature. The observed spectral difference is similar to that of a planar air/water surface at a temperature that is ~50 K lower. Supercooling the droplets to 263 K does not change the surface structure. Below the homogeneous ice nucleation temperature, a single vibrational mode is present with a similar mean hydrogen-bond strength as for a planar ice/air interface.

  5. Three-dimensional picture of dynamical structure in liquid water

    NASA Astrophysics Data System (ADS)

    Svishchev, Igor M.; Zassetsky, Alexander Yu.

    2000-01-01

    This paper presents a methodology with which to study the local density distributions in molecular liquids and their fluctuations in any spatial direction. The distinct part of the van Hove density-density correlation function for liquid water is calculated in molecular dynamics simulations. Because of the pronounced nonspherical intermolecular interactions this pair-density function is direction dependent in the local molecular frame. We explicitly resolve the distinct van Hove function in the local frame of water molecules. The dynamics of the tetrahedrally coordinated (hydrogen bonded) and the interstitial molecules in liquid water are examined. The spectrum of the pair-density fluctuations for the tetrahedrally coordinated molecules in supercooled and ambient water exhibits a well-known translational mode at 200 cm-1 and a collective relaxation mode at lower frequencies, at approximately 10 cm-1 at 263 K. The correlation time of this relaxation process decreases with temperature, from 2.2 ps at 238 K to 1.4 ps at 298 K. The spectrum for the interstitial coordination also features a 10 cm-1 mode. It represents a secondary relaxation process in water different from a much slower Debye process. As temperature increases this relaxation mode tends to disappear from the pair-density fluctuations.

  6. Electronic stopping in liquid water from first principles: An application of large-scale real-time TDDFT simulations

    NASA Astrophysics Data System (ADS)

    Reeves, Kyle; Yao, Yi; Kanai, Yosuke

    Electronic stopping describes the transfer of energy from a highly-energetic charged particle to electrons in a material. This process induces massive electronic excitations via interaction between the material and the highly localized electric field from the charged particle. Understanding this phenomenon in condensed matter systems under proton irradiation has implications in various modern technologies. First-principles simulations, based on our recently-developed large-scale real-time time-dependent density functional theory approach, provide a detailed description of how electrons are excited via a non-equilibrium energy transfer from protons on the attosecond time scale. We apply this computational approach to the important case of liquid water under proton irradiation. Our work reveals several key features of the excitation dynamics at the mesoscopic and molecular levels which support a clearer understanding of the water radiolysis mechanism under proton irradiation. Importantly, we will demonstrate a first-principles determination of the energy transfer rate, (i.e. electronic stopping power) in liquid water, and a comparison to existing empirical models will be presented. We will conclude by discussing how the exchange-correlation approximation influences the calculation of the electronic stopping power.

  7. Numerical studies on the separation performance of liquid- liquid Hydrocyclone for higher water-cut wells

    NASA Astrophysics Data System (ADS)

    Osei, H.; Al-Kayiem, H. H.; Hashim, F. M.

    2015-12-01

    Liquid-liquid hydrocyclones have nowadays become very useful in the oil industry because of their numerous applications. They can be installed downhole in the case of a well that produces higher water-oil ratios. The design of a liquid-liquid hydrocyclone for such a task is critical and every geometric part of the hydrocyclone has a part to play as far as separation is concerned. This work, through validated numerical technique, investigated the liquid-liquid hydrocyclone performance for the cases of single-inlet and dual-inlets, with different upper cylindrical lengths, specifically, 30mm and 60mm.It was observed that the hydrocyclones with the 30mm upper cylindrical section perform better than the ones with 60 mm upper cylindrical section. It was again noted that, even though higher number of tangential inlets increases the swirl intensity, they have the tendency to break up the oil droplets within the hydrocyclone because of increasing shear and jet flow interaction.

  8. Study of the ST2 model of water close to the liquid-liquid critical point.

    PubMed

    Sciortino, Francesco; Saika-Voivod, Ivan; Poole, Peter H

    2011-11-28

    We perform successive umbrella sampling grand canonical Monte Carlo computer simulations of the original ST2 model of water in the vicinity of the proposed liquid-liquid critical point, at temperatures above and below the critical temperature. Our results support the previous work of Y. Liu, A. Z. Panagiotopoulos and P. G. Debenedetti [J. Chem. Phys., 2009, 131, 104508], who provided evidence for the existence and location of the critical point for ST2 using the Ewald method to evaluate the long-range forces. Our results therefore demonstrate the robustness of the evidence for critical behavior with respect to the treatment of the electrostatic interactions. In addition, we verify that the liquid is equilibrated at all densities on the Monte Carlo time scale of our simulations, and also that there is no indication of crystal formation during our runs. These findings demonstrate that the processes of liquid-state relaxation and crystal nucleation are well separated in time. Therefore, the bimodal shape of the density of states, and hence the critical point itself, is a purely liquid-state phenomenon that is distinct from the crystal-liquid transition.

  9. Probing Hydrophilic Interface of Solid/Liquid-Water by Nanoultrasonics

    PubMed Central

    Mante, Pierre-Adrien; Chen, Chien-Cheng; Wen, Yu-Chieh; Chen, Hui-Yuan; Yang, Szu-Chi; Huang, Yu-Ru; -Ju Chen, I.; Chen, Yun-Wen; Gusev, Vitalyi; Chen, Miin-Jang; Kuo, Jer-Lai; Sheu, Jinn-Kong; Sun, Chi-Kuang

    2014-01-01

    Despite the numerous devoted studies, water at solid interfaces remains puzzling. An ongoing debate concerns the nature of interfacial water at a hydrophilic surface, whether it is more solid-like, ice-like, or liquid-like. To answer this question, a complete picture of the distribution of the water molecule structure and molecular interactions has to be obtained in a non-invasive way and on an ultrafast time scale. We developed a new experimental technique that extends the classical acoustic technique to the molecular level. Using nanoacoustic waves with a femtosecond pulsewidth and an ångström resolution to noninvasively diagnose the hydration structure distribution at ambient solid/water interface, we performed a complete mapping of the viscoelastic properties and of the density in the whole interfacial water region at hydrophilic surfaces. Our results suggest that water in the interfacial region possesses mixed properties and that the different pictures obtained up to now can be unified. Moreover, we discuss the effect of the interfacial water structure on the abnormal thermal transport properties of solid/liquid interfaces. PMID:25176017

  10. Intra-oral administration of rebamipide liquid prevents tongue injuries induced by X-ray irradiation in rats.

    PubMed

    Nakashima, Takako; Uematsu, Naoya; Sakurai, Kazushi

    2017-07-01

    Oral mucositis is a common and serious side effect in patients who undergo cytotoxic cancer therapies. The purpose of this study was to investigate the preventive effects of rebamipide on radiation-induced glossitis model in rats. Glossitis was induced by a single dose of 15 Gy of X-rays to the snouts of rats (day 0). A novel form of rebamipide liquid comprising its submicronized crystals was administered intra-orally. The preventive effect of rebamipide on tongue injuries was macroscopically evaluated on day 7 following irradiation. The pretreatment period, dosing frequency, and dose dependency of rebamipide were examined. Two percent rebamipide liquid, administered six times a day for 14 days from day -7 to day 6, significantly decreased the ulcer-like area. However, no significant effect was observed when rebamipide was given either from day -4 or from day -1. Four or six times daily, 2% rebamipide liquid significantly inhibited the ulcer-like injury area ratio, but not when given twice daily. Rebamipide liquid, 1, 2, and 4% six times daily significantly reduced the area ratios of total injury and ulcer-like injury in a dose-dependent manner. Gene expression and protein levels of proinflammatory cytokines and chemokines were dramatically elevated in the irradiated tongues of control rats on day 7 without rebamipide liquid treatment. They were dose-dependently and significantly suppressed in rebamipide-treated groups. Intra-oral administration of rebamipide liquid prevented oral mucositis dose-dependently accompanied by the suppression of inflammatory expression in the radiation-induced rats' glossitis model.

  11. Liquid-vapor oscillations of water in hydrophobic nanopores.

    PubMed

    Beckstein, Oliver; Sansom, Mark S P

    2003-06-10

    Water plays a key role in biological membrane transport. In ion channels and water-conducting pores (aquaporins), one-dimensional confinement in conjunction with strong surface effects changes the physical behavior of water. In molecular dynamics simulations of water in short (0.8 nm) hydrophobic pores the water density in the pore fluctuates on a nanosecond time scale. In long simulations (460 ns in total) at pore radii ranging from 0.35 to 1.0 nm we quantify the kinetics of oscillations between a liquid-filled and a vapor-filled pore. This behavior can be explained as capillary evaporation alternating with capillary condensation, driven by pressure fluctuations in the water outside the pore. The free-energy difference between the two states depends linearly on the radius. The free-energy landscape shows how a metastable liquid state gradually develops with increasing radius. For radii > approximately 0.55 nm it becomes the globally stable state and the vapor state vanishes. One-dimensional confinement affects the dynamic behavior of the water molecules and increases the self diffusion by a factor of 2-3 compared with bulk water. Permeabilities for the narrow pores are of the same order of magnitude as for biological water pores. Water flow is not continuous but occurs in bursts. Our results suggest that simulations aimed at collective phenomena such as hydrophobic effects may require simulation times >50 ns. For water in confined geometries, it is not possible to extrapolate from bulk or short time behavior to longer time scales.

  12. Ultrasonic irradiation of deuterium-loaded palladium particles suspended in heavy water

    SciTech Connect

    Jorne, J.

    1996-01-01

    Ultrasonic irradiation of a slurry of deuterium-loaded palladium powder (1 {mu}m) suspended in heavy water causes cavitation and high-speed collisions between the palladium particles. High local temperatures, estimated at above the melting point of palladium (1828 K), cause melting and interparticle fusion. The expectation that such collisions can induce high stresses within the palladium particles and lead to favorable conditions for nuclear cold fusion of the deuterium atoms within the palladium lattice is checked by measuring the neutron rates during ultrasonic irradiation. Several bursts of neutron counting are observed and can be accounted for as background anomalism, although the highest observed neutron rate is about four times the background and cannot be explained as background. The X-ray photoelectron spectroscopy analysis of the deuterium-loaded palladium powders reveals that after ultrasonic irradiation in heavy water, the palladium powder becomes partially oxidized and undergoes some compositional changes. 18 refs., 7 figs., 1 tab.

  13. Observation of bubble formation in water during microwave irradiation by dynamic light scattering

    NASA Astrophysics Data System (ADS)

    Asakuma, Yusuke; Munenaga, Takuya; Nakata, Ryosuke

    2016-09-01

    A microwave reactor was designed for in situ observation of nano- and micro-bubbles, and size profiles during and after irradiation were measured with respect to irradiation power and time. Bubble formation in water during irradiation was observed even at temperatures below the boiling point of water. The maximum size strongly depended on radiation power and time, even at a given temperature. Nano-particles in the dispersion medium were found to play an important role in achieving more stable nucleation of bubbles around particles, and stable size distributions were obtained from clear autocorrelation by a dynamic light scattering system. Moreover, a combination of microwave induction heating and the addition of nano-particles to the dispersion medium can prevent heterogeneous nucleation of bubbles on the cell wall. Quantitative nano-bubble size profiles obtained by in situ observation provide useful information regarding microwave-based industrial processes for nano-particle production.

  14. The liquid water balance of the Greenland ice sheet

    NASA Astrophysics Data System (ADS)

    Steger, Christian; Reijmer, Carleen; van den Broeke, Michiel

    2017-04-01

    Mass loss from the Greenland Ice Sheet (GrIS) is an increasingly important contributor to global sea level rise. During the last decade, the mass loss was dominated by meltwater runoff. Linking actual runoff from the ice sheet to melt and other forms of liquid water input at the surface (rainfall and condensation) is however complex, as liquid water may be retained within the ice sheet due to refreezing and/or (perennial) storage. In the ablation zone on bare ice, liquid water runs of laterally at the surface, accumulates in supraglacial lakes or enters the ice sheet's en- or subglacial hydraulic system via moulins and crevasses. In the higher elevated accumulation zone, liquid water percolates into the porous firn layer and part of it may be retained due to refreezing and/or perennial storage in so called firn aquifers. In this study, we investigate the liquid water balance of the GrIS focussing on the role of the firn layer. For this purpose, we ran SNOWPACK, a relatively complex one-dimensional snow model, on a horizontal resolution of ˜ 11km and for the transient period of 1960 to 2015. At the snow-atmosphere-interface, the model was forced by output of the regional atmospheric climate model RACMO2.3. A comparison of SNOWPACK with in-situ observations (firn density profiles) and remote sensing data (firn aquifer locations inferred from radar measurements) indicated a good agreement for most climatic conditions. On a GrIS-wide scale, the modelled surface mass balance of SNOWPACK exhibits, in combination with ice-discharge data for ocean-terminating glaciers, an excellent agreement with GRACE data for the period 2003 - 2012. GrIS-integrated amounts of surface melt reveal a significant positive trend (+11.6Gta-2) in the second half of the simulation period. Within this interval, the trend in runoff is larger (+8.3Gta-2) than the one in refreezing (+3.6Gta-2), which results in an overall decrease of the refreezing fraction. This decrease is for instance less

  15. Water Tank with Capillary Air/Liquid Separation

    NASA Technical Reports Server (NTRS)

    Ungar, Eugene K.; Smith, Frederick; Edeen, Gregg; Almlie, Jay C.

    2010-01-01

    A bladderless water tank (see figure) has been developed that contains capillary devices that allow it to be filled and emptied, as needed, in microgravity. When filled with water, the tank shields human occupants of a spacecraft against cosmic radiation. A membrane that is permeable by air but is hydrophobic (neither wettable nor permeable by liquid water) covers one inside surface of the tank. Grooves between the surface and the membrane allow air to flow through vent holes in the surface as the tank is filled or drained. A margin of wettable surface surrounds the edges of the membrane, and all the other inside tank surfaces are also wettable. A fill/drain port is located in one corner of the tank and is covered with a hydrophilic membrane. As filling begins, water runs from the hydrophilic membrane into the corner fillets of the tank walls. Continued filling in the absence of gravity will result in a single contiguous air bubble that will be vented through the hydrophobic membrane. The bubble will be reduced in size until it becomes spherical and smaller than the tank thickness. Draining the tank reverses the process. Air is introduced through the hydrophobic membrane, and liquid continuity is maintained with the fill/drain port through the corner fillets. Even after the tank is emptied, as long as the suction pressure on the hydrophilic membrane does not exceed its bubble point, no air will be drawn into the liquid line.

  16. A single-site multipole model for liquid water

    NASA Astrophysics Data System (ADS)

    Tran, Kelly N.; Tan, Ming-Liang; Ichiye, Toshiko

    2016-07-01

    Accurate and efficient empirical potential energy models that describe the atomistic interactions between water molecules in the liquid phase are essential for computer simulations of many problems in physics, chemistry, and biology, especially when long length or time scales are important. However, while models with non-polarizable partial charges at four or five sites in a water molecule give remarkably good values for certain properties, deficiencies have been noted in other properties and increasing the number of sites decreases computational efficiency. An alternate approach is to utilize a multipole expansion of the electrostatic potential due to the molecular charge distribution, which is exact outside the charge distribution in the limits of infinite distances or infinite orders of multipoles while partial charges are a qualitative representation of electron density as point charges. Here, a single-site multipole model of water is presented, which is as fast computationally as three-site models but is also more accurate than four- and five-site models. The dipole, quadrupole, and octupole moments are from quantum mechanical-molecular mechanical calculations so that they account for the average polarization in the liquid phase, and represent both the in-plane and out-of-plane electrostatic potentials of a water molecule in the liquid phase. This model gives accurate thermodynamic, dynamic, and dielectric properties at 298 K and 1 atm, as well as good temperature and pressure dependence of these properties.

  17. GAS EVOLUTION FROM INSULATING MATERIALS FOR SUPERCONDUCTING COIL OF ITER BY GAMMA RAY IRRADIATION AT LIQUID NITROGEN TEMPERATURE

    SciTech Connect

    Idesaki, A.; Morishita, N.; Ohshima, T.; Koizumi, N.; Sugimoto, M.; Okuno, K.

    2008-03-03

    A laminated material composed of glass cloth/polyimide film/epoxy resin will be used as an insulating material for superconducting coil of International Thermonuclear Experimental Reactor (ITER). In order to keep safe and stable operation of the superconducting coil system, it is indispensable to evaluate radiation resistance of the material, because the material is exposed to severe environments such as high radiation field and low temperature of 4 K. Especially, it is important to estimate the amount of gases evolved from the insulating material by irradiation, because the gases affect on the purifying system of liquid helium in the superconducting coil system. In this work, the gas evolution from the laminated material by gamma ray irradiation at liquid nitrogen temperature (77 K) was investigated, and the difference of gas evolution behavior due to difference of composition in the epoxy resin was discussed. It was found that the main gases evolved from the laminated material by the irradiation were hydrogen, carbon monoxide and carbon dioxide, and that the amount of gases evolved from the epoxy resin containing cyanate ester was about 60% less than that from the epoxy resin containing tetraglycidyl-diaminophenylmethane (TGDDM)

  18. Water corrosion measurements on tungsten irradiated with high energy protons and spallation neutrons

    NASA Astrophysics Data System (ADS)

    Maloy, Stuart A.; Scott Lillard, R.; Sommer, Walter F.; Butt, Darryl P.; Gac, Frank D.; Willcutt, Gordon J.; Louthan, McIntyre R.

    2012-12-01

    A detailed analysis was performed on the degradation of a tungsten target under water cooling while being exposed to a 761 MeV proton beam at an average current of 0.867 mA to a maximum fluence of 1.3 × 1021 protons/cm2. The target consisted of 3 mm diameter tungsten rods arranged in bundles and cooled with deionized water flowing over their length. Degradation of the tungsten was measured through analyzing water resistivity, tungsten concentration in water samples that were taken during irradiation and through dimensional measurements on the rods after irradiation. Chemical analysis of irradiated water samples showed W concentrations up to 35 μg/ml. Gamma analysis showed increases in concentrations of many isotopes including W-178, Lu-171, Tm-167, Tm-166, Yb-169 and Hf-175. Dimensional measurements performed after irradiation on the W rods revealed a decrease in diameter as a function of position that followed closely the Gaussian proton beam profile along the rod length and indicated a definite beam-effect. A general decrease in diameter, especially on the coolant-water entrance point where turbulent flow was likely, also suggests a chemically and mechanically-driven corrosion effect. A method to estimate the apparent corrosion rate based on proton fluence is presented and application of this method estimates the material loss rate at about 1.9 W atoms/incident proton. From this result, the corrosion rate of tungsten in a 761 MeV, 0.867 mA proton beam was calculated to be 0.073 cm/full power year. of irradiation.

  19. The corrosion of materials in water irradiated by 800 MeV protons

    NASA Astrophysics Data System (ADS)

    Lillard, R. S.; Pile, D. L.; Butt, D. P.

    2000-02-01

    A method for measuring the real-time corrosion rates for Alloy 718, stainless steels (SS) 304L and 316L nuclear grade (NG), aluminum alloys 5052 (Al5052) and 6061 (Al6061), copper (Cu), tantalum (Ta), and tungsten (W) in two separate water systems that were irradiated by 800 MeV protons is presented. The first water system was fabricated entirely of 304 SS, thoroughly cleaned before operation, and employed hydrogen water chemistry (HWC) to mitigate the formation of some of the radiolysis products. The samples were adequately shielded from the irradiation cavity such that only the effects of water chemistry were investigated. Over the course of that irradiation period the corrosion rates for 304L SS, 316L-NG SS, Alloy 718, and Ta were less than 0.12 μm/yr. For Al6061 and Al5052, the corrosion rates were of the order of 0.50-2.0 μm/yr. The corrosion rate of W was relatively high between 5.0 and 30 μm/yr. The second water system, fabricated from copper piping and steel components, was not cleaned prior to operation, and employed no HWC. In comparison to the other system, the corrosion rates in the copper/steel system were 1-3 orders of magnitude higher. These results are discussed in terms of water radiolysis and water impurity levels.

  20. On the implications of aerosol liquid water and phase ...

    EPA Pesticide Factsheets

    Organic compounds and liquid water are major aerosol constituents in the southeast United States (SE US). Water associated with inorganic constituents (inorganic water) can contribute to the partitioning medium for organic aerosol when relative humidities or organic matter to organic carbon (OM ∕ OC) ratios are high such that separation relative humidities (SRH) are below the ambient relative humidity (RH). As OM ∕ OC ratios in the SE US are often between 1.8 and 2.2, organic aerosol experiences both mixing with inorganic water and separation from it. Regional chemical transport model simulations including inorganic water (but excluding water uptake by organic compounds) in the partitioning medium for secondary organic aerosol (SOA) when RH  >  SRH led to increased SOA concentrations, particularly at night. Water uptake to the organic phase resulted in even greater SOA concentrations as a result of a positive feedback in which water uptake increased SOA, which further increased aerosol water and organic aerosol. Aerosol properties, such as the OM ∕ OC and hygroscopicity parameter (κorg), were captured well by the model compared with measurements during the Southern Oxidant and Aerosol Study (SOAS) 2013. Organic nitrates from monoterpene oxidation were predicted to be the least water-soluble semivolatile species in the model, but most biogenically derived semivolatile species in the Community Multiscale Air Quality (CMAQ) model were hig

  1. On the implications of aerosol liquid water and phase ...

    EPA Pesticide Factsheets

    Organic compounds and liquid water are major aerosol constituents in the southeast United States (SE US). Water associated with inorganic constituents (inorganic water) can contribute to the partitioning medium for organic aerosol when relative humidities or organic matter to organic carbon (OM ∕ OC) ratios are high such that separation relative humidities (SRH) are below the ambient relative humidity (RH). As OM ∕ OC ratios in the SE US are often between 1.8 and 2.2, organic aerosol experiences both mixing with inorganic water and separation from it. Regional chemical transport model simulations including inorganic water (but excluding water uptake by organic compounds) in the partitioning medium for secondary organic aerosol (SOA) when RH  >  SRH led to increased SOA concentrations, particularly at night. Water uptake to the organic phase resulted in even greater SOA concentrations as a result of a positive feedback in which water uptake increased SOA, which further increased aerosol water and organic aerosol. Aerosol properties, such as the OM ∕ OC and hygroscopicity parameter (κorg), were captured well by the model compared with measurements during the Southern Oxidant and Aerosol Study (SOAS) 2013. Organic nitrates from monoterpene oxidation were predicted to be the least water-soluble semivolatile species in the model, but most biogenically derived semivolatile species in the Community Multiscale Air Quality (CMAQ) model were hig

  2. Hydrogen bonding definitions and dynamics in liquid water.

    PubMed

    Kumar, R; Schmidt, J R; Skinner, J L

    2007-05-28

    X-ray and neutron diffractions, vibrational spectroscopy, and x-ray Raman scattering and absorption experiments on water are often interpreted in terms of hydrogen bonding. To this end a number of geometric definitions of hydrogen bonding in water have been developed. While all definitions of hydrogen bonding are to some extent arbitrary, those involving one distance and one angle for a given water dimer are unnecessarily so. In this paper the authors develop a systematic procedure based on two-dimensional potentials of mean force for defining cutoffs for a given pair of distance and angular coordinates. They also develop an electronic structure-based definition of hydrogen bonding in liquid water, related to the electronic occupancy of the antibonding OH orbitals. This definition turns out to be reasonably compatible with one of the distance-angle geometric definitions. These two definitions lead to an estimate of the number of hydrogen bonds per molecule in liquid simple point charge/extended (SPC/E) water of between 3.2 and 3.4. They also used these and other hydrogen-bond definitions to examine the dynamics of local hydrogen-bond number fluctuations, finding an approximate long-time decay constant for SPC/E water of between 0.8 and 0.9 ps, which corresponds to the time scale for local structural relaxation.

  3. Appearance of the therapeutically irradiated breast on whole-breast water-path ultrasonography

    SciTech Connect

    Meyer, J.E.; Kopans, D.B.

    1983-05-01

    The sonographic appearance of the breast on whole-breast water-path ultrasonography in 30 patients with prior therapeutic irradiation for carcinoma is described. Skin thickening, a nonspecific increase in echogenicity of the subcutaneous fat, loss of volume, and architectural asymmetry are the prominent features.

  4. Gamma irradiation of pharmaceutical compounds, nitroimidazoles, as a new alternative for water treatment.

    PubMed

    Sánchez-Polo, M; López-Peñalver, J; Prados-Joya, G; Ferro-García, M A; Rivera-Utrilla, J

    2009-09-01

    The main objectives of this study were: (1) to investigate the decomposition and mineralization of nitroimidazoles (Metronidazole [MNZ], Dimetridazole [DMZ], and Tinidazole [TNZ]) in waste and drinking water using gamma irradiation; (2) to study the decomposition kinetics of these nitroimidazoles; and (3) to evaluate the efficacy of nitroimidazole removal using radical promoters and scavengers. The results obtained showed that nitroimidazole concentrations decreased with increasing absorbed dose. No differences in irradiation kinetic constant were detected for any nitroimidazole studied (0.0014-0.0017 Gy(-1)). The decomposition yield was higher under acidic conditions than in neutral and alkaline media. Results obtained showed that, at appropriate concentrations, H(2)O(2) accelerates MNZ degradation by generating additional HO(); however, when the dosage of H(2)O(2) exceeds the optimal concentration, the efficacy of MNZ degradation is reduced. The presence of t-BuOH (HO() radical scavenger) and thiourea (HO(), H() and e(aq)(-) scavenger) reduced the MNZ irradiation rate, indicating that degradation of this pollutant can take place via two pathways: oxidation by HO() radicals and reduction by e(aq)(-) and H(). MNZ removal rate was slightly lower in subterranean and surface waters than in ultrapure water and was markedly lower in wastewater. Regardless of the water chemical composition, MNZ gamma irradiation can achieve i) a decrease in the concentration of dissolved organic carbon, and ii) a reduction in the toxicity of the system with higher gamma absorbed dose.

  5. [Radioprotective effect of drinking sulfate mineral water on spermatogenesis in offspring of irradiated male rats].

    PubMed

    Korolev, Iu N; Geniatulina, M S; Nikulina, L A; Kurilo, L F

    2003-01-01

    Histological and electron-microscopic studies of a radioprotective action of drinking sulphate mineral water (SMW) on spermatogenesis of irradiated male rats' progeny have found that SMW used before radiation (2 Gy) and 10 days after it is able to reduce postradiation sequelae in the progeny (2-5 month and 1.5 year old rats) testes.

  6. Ultrasonic irradiation accelerated cyclopalladated ferrocenylimines catalyzed Suzuki reaction in neat water.

    PubMed

    Zhang, Jinli; Yang, Fan; Ren, Gerui; Mak, Thomas C W; Song, Maoping; Wu, Yangjie

    2008-02-01

    Both conventional heating and ultrasound effect on the cyclopalladated ferrocenylimines catalyzed Suzuki reaction of phenylboronic acid with a range of arylhalides in neat water was investigated. Heterogenous reaction of electron-withdrawing arylchlorides with phenylboronic acid could also result in good yields by using Cat. 2. It was found that the ultrasonic irradiation could dramatically accelerate the Suzuki reaction to achieve comparable results.

  7. Photochemical oxidation of water and reduction of polyoxometalate anions at interfaces of water with ionic liquids or diethylether

    PubMed Central

    Bernardini, Gianluca; Wedd, Anthony G.; Zhao, Chuan; Bond, Alan M.

    2012-01-01

    Photoreduction of [P2W18O62]6-, [S2Mo18O62]4-, and [S2W18O62]4- polyoxometalate anions (POMs) and oxidation of water occurs when water–ionic liquid and water–diethylether interfaces are irradiated with white light (275–750 nm) or sunlight. The ionic liquids (ILs) employed were aprotic ([Bmim]X; Bmim = (1-butyl-3-methylimidazolium,X = BF4,PF6) and protic (DEAS = diethanolamine hydrogen sulphate; DEAP = diethanolamine hydrogen phosphate). Photochemical formation of reduced POMs at both thermodynamically stable and unstable water–IL interfaces led to their initial diffusion into the aqueous phase and subsequent extraction into the IL phase. The mass transport was monitored visually by color change and by steady-state voltammetry at microelectrodes placed near the interface and in the bulk solution phases. However, no diffusion into the organic phase was observed when [P2W18O62]6- was photo-reduced at the water–diethylether interface. In all cases, water acted as the electron donor to give the overall process: 4POM + 2H2O + hν → 4POM- + 4H+ + O2. However, more highly reduced POM species are likely to be generated as intermediates. The rate of diffusion of photo-generated POM- was dependent on the initial concentration of oxidized POM and the viscosity of the IL (or mixed phase system produced in cases in which the interface is thermodynamically unstable). In the water-DEAS system, the evolution of dioxygen was monitored in situ in the aqueous phase by using a Clark-type oxygen sensor. Differences in the structures of bulk and interfacial water are implicated in the activation of water. An analogous series of reactions occurred upon irradiation of solid POM salts in the presence of water vapor. PMID:22753501

  8. Liquid-liquid critical point in a simple analytical model of water

    NASA Astrophysics Data System (ADS)

    Urbic, Tomaz

    2016-10-01

    A statistical model for a simple three-dimensional Mercedes-Benz model of water was used to study phase diagrams. This model on a simple level describes the thermal and volumetric properties of waterlike molecules. A molecule is presented as a soft sphere with four directions in which hydrogen bonds can be formed. Two neighboring waters can interact through a van der Waals interaction or an orientation-dependent hydrogen-bonding interaction. For pure water, we explored properties such as molar volume, density, heat capacity, thermal expansion coefficient, and isothermal compressibility and found that the volumetric and thermal properties follow the same trends with temperature as in real water and are in good general agreement with Monte Carlo simulations. The model exhibits also two critical points for liquid-gas transition and transition between low-density and high-density fluid. Coexistence curves and a Widom line for the maximum and minimum in thermal expansion coefficient divides the phase space of the model into three parts: in one part we have gas region, in the second a high-density liquid, and the third region contains low-density liquid.

  9. A physically-based retrieval of cloud liquid water from SSM/I measurements

    NASA Technical Reports Server (NTRS)

    Greenwald, Thomas J.; Stephens, Graeme L.; Vonder Haar, Thomas H.

    1992-01-01

    A simple physical scheme is proposed for retrieving cloud liquid water over the ice-free global oceans from Special Sensor Microwave/Imager (SSM/I) observations. Details of the microwave retrieval scheme are discussed, and the microwave-derived liquid water amounts are compared with the ground radiometer and AVHRR-derived liquid water for stratocumulus clouds off the coast of California. Global distributions of the liquid water path derived by the method proposed here are presented.

  10. Liquid-Liquid Phase Equilibria and Interactions between Droplets in Water-in-Oil Microemulsions.

    PubMed

    Yin, Tianxiang; Wang, Mingjie; Tao, Xiaoyi; Shen, Weiguo

    2016-12-20

    The liquid-liquid phase equilibria of [water/sodium bis(2-ethylhexyl)sulfosuccinate (AOT)/n-decane] with the molar ratio w0 of water to AOT being 37.9 and [water/AOT/ethoxylated-2,5,8,11-tetramethyl-6-dodecyne-5,8-diol(Dynol-604)/n-decane] with w0 = 37.9 and the mole fraction α of Dynol-604 in the total surfactants being 0.158 were measured in this study. From the data collected in the critical region, the critical exponent β corresponding to the width of the coexistence curve was determined, which showed good agreement with the 3D-Ising value. A thermodynamic approach based on the Carnahan-Starling-van der Waals type equation was proposed to describe the coexistence curves and to deduce the interaction properties between droplets in the microemulsions. The interaction enthalpies were found to be positive for the studied systems, which evidenced that the entropy effect dominated the phase separations as the temperature increased. The addition of Dynol-604 into the (water/AOT/n-decane) microemulsion resulted in the decrease in the critical temperature and the interaction enthalpy. Combining the liquid-liquid equilibrium data for (water/AOT/n-decane) microemulsions with various w0 values determined previously, it was shown that the interaction enthalpy decreased with w0 and tended to change its sign at low w0, which coincided with the results from the isothermal titration calorimetry investigation. All of these behaviors were interpreted by the effects of entropy and enthalpy and their competition, which resulted from the release of solvent molecules entrapped in the interface of microemulsion droplets and were dependent on the rigidity of the surfactant layers and the size of the droplet.

  11. An experimental study on the motion of water droplets in oil under ultrasonic irradiation.

    PubMed

    Luo, Xiaoming; He, Limin; Wang, Hongping; Yan, Haipeng; Qin, Yahua

    2016-01-01

    The motion of a single water droplet in oil under ultrasonic irradiation is investigated with high-speed photography in this paper. First, we described the trajectory of water droplet in oil under ultrasonic irradiation. Results indicate that in acoustic field the motion of water droplet subjected to intermittent positive and negative ultrasonic pressure shows obvious quasi-sinusoidal oscillation. Afterwards, the influence of major parameters on the motion characteristics of water droplet was studied, such as acoustic intensity, ultrasonic frequency, continuous phase viscosity, interfacial tension, and droplet diameter, etc. It is found that when the acoustic intensity and frequency are 4.89 W cm(-2) and 20 kHz respectively, which are the critical conditions, the droplet varying from 250 to 300 μm in lower viscous oil has the largest oscillation amplitude and highest oscillation frequency.

  12. Photochemical Degradation of Organic Pollutants in Liquid Water and Ice

    NASA Astrophysics Data System (ADS)

    Sprenkle, A. M.; Grannas, A. M.

    2006-12-01

    Arctic snow and ice play an important role as reactive media in the environment. A variety of species are photochemically generated from snow/ice, including carbonyl compounds, alkyl halides, molecular halogens, and nitrogen oxides. However, the fate of anthropogenic organic pollutants in snow and ice is largely unknown. Volatile pollutants evaporate from lower, warmer latitudes and condense out in the higher, colder latitudes by a process known as global distillation, leading to enhanced concentrations of a variety of pollutants in polar regions. Here we present recent results of photochemical degradation studies of several important organic pollutants including aldrin, dieldrin, hexachlorobenzene, and 3,3',4,5'-tetrachlorobiphenyl. Direct and indirect (with H2O2) pathways were studied in both liquid water and ice forms. Aldrin and 3,3',4,5'-tetrachlorobiphenyl have shown the most reactivity, both degrading significantly via the direct and indirect pathway in liquid water and ice. Dieldrin has shown reactivity under both direct and indirect liquid conditions, while HCB is only reactive under indirect liquid conditions. These results indicate that ice can serve as an important reactive surface for anthropogenic organic pollutants. Snow/ice photochemistry should be included in models of pollutant fate, but further studies are necessary to determine which pollutants are most affected by ice photochemistry under typical environmental conditions.

  13. X-Ray Spectroscopy of the Liquid Water Surface

    NASA Astrophysics Data System (ADS)

    Saykally, Richard

    2004-03-01

    We have developed a new experiment for probing molecular details of liquid-vapor interfaces of volatile substances and their solutions under equilibrium conditions. Electronic and geometric structures of interfacial molecules are probed by EXAFS and NEXAFS methods in the soft X-ray region, using the Advanced Light Source, Berkeley, CA. Liquids are introduced into a high vacuum environment through the use of liquid microjets, which have been characterized independently by Raman spectroscopy. Detection of ions and electrons produced by the Auger avalanche probe the bulk and surface regions of the microjet, respectively, as a result of their different escape depths. Our first efforts involved a comparative study of the interfaces of water and methanol, wherein we detailed the first observation of surface relaxation for a liquid. Analysis of EXAFS data yielded a 6distance at the water interface, whereas a 5was found for methanol. NEXAFS measurements, interpreted in terms of density functional theory simulations, indicate a large population of interfacial water molecules having two free OH bonds ("acceptor only molecules"). This complements the "single donor" species identified in sum frequency generation experiments. These results are supported by recent theoretical calculations. For methanol and other simple alcohols, the data indicate that free alkyl groups extend into the vapor part of the interface. Preliminary results for aqueous solutions, as well as for other pure liquids, have been obtained and are presently under analysis. REFERENCES 1. K.R. Wilson, R.D. Schaller, B.S. Rude, T. Catalano, D.T. Co, J.D. Bozek, and R.J. Saykally, "Surface relaxation in liquid water and methanol studied by X-ray absorption spectroscopy," J. Chem. Phys 117,7738(2002). 2. K.R. Wilson, M. Cavalleri, B.S. Rude, R.D. Schaller, A. Nilsson, L.G.M. Pettersson, N. Goldman, T. Catalano, J.D. Bozek, and R.J. Saykally, "Characterization of hydrogen bond acceptor molecules at the water surface

  14. Stable and water-tolerant ionic liquid ferrofluids.

    PubMed

    Jain, Nirmesh; Zhang, Xiaoli; Hawkett, Brian S; Warr, Gregory G

    2011-03-01

    Ionic liquid ferrofluids have been prepared containing both bare and sterically stabilized 8-12 nm diameter superparamagnetic iron oxide nanoparticles, which remain stable for several months in both protic ethylammonium and aprotic imidazolium room-temperature ionic liquids. These ferrofluids exhibit spiking in static magnetic fields similar to conventional aqueous and nonaqueous ferrofluids. Ferrofluid stability was verified by following the flocculation and settling behavior of dilute nanoparticle dispersions. Although bare nanoparticles showed excellent stability in some ILs, they were unstable in others, and exhibited limited water tolerance. Stability was achieved by incorporating a thin polymeric steric stabilization layer designed to be compatible with the IL. This confers the added benefit of imbuing the ILF with a high tolerance to water.

  15. Gas-phase and liquid-phase pre-irradiation grafting of AAc onto LDPE and HDPE films for pervaporation membranes

    NASA Astrophysics Data System (ADS)

    Zhigong, Rao; Guixiang, Li; Sugo, Takanobu; Okamoto, Jiro

    A study has been made on gas-phase and liquid-phase pre-irradiation grafting of acrylic acid onto LDPE and HDPE films for pervaporation membranes of ethanol-water mixtures. It was found that the degree of grafting, percent volume change of grafted membranes and length of grafting chains depend on the methods of grafting, crystal state of substrate films and diffusion rate of the monomer in the films. The pervaporation characteristics of grafted membranes is influenced directly by the surface hydrophilicity of grafted membranes, temperature of the feed, degree of grafting, crosslinking of grafted chains and alkaline metal ions in the functional groups. The potassium ion exchange membrane of HDPE synthesized by gas-phase grafting has better pervaporation efficiency. At 80 wt% ethanol in the feed, 25°C feed temperature and 70% degree of grafting a grafted membrane has a 0.65 kg/m 2h flux and a separation factor of 20.

  16. Ionic-liquid-based dispersive liquid-liquid microextraction combined with high-performance liquid chromatography for the determination of multiclass pesticide residues in water samples.

    PubMed

    Tadesse, Bezuayehu; Teju, Endale; Gure, Abera; Megersa, Negussie

    2015-03-01

    Ionic-liquid-based dispersive liquid-liquid microextraction in combination with high-performance liquid chromatography and diode array detection has been proposed for the simultaneous analysis of four multiclass pesticide residues including carbaryl, methidathion, chlorothalonil, and ametryn from water samples. The major experimental parameters including the type and volume of ionic liquid, sample pH, type, and volume of disperser solvent and cooling time were investigated and optimum conditions were established. Under the optimum experimental conditions, limits of detection and quantification of the method were in the range of 0.1-1.8 and 0.4-5.9 μg/L, respectively, with satisfactory enrichment factors ranging from 10-20. The matrix-matched calibration curves, which were constructed for lake water, as a representative matrix were linear over wide range with coefficients of determination of 0.996 or better. Intra- and interday precisions, expressed as relative standard deviations, were in the range of 1.1-9.7 and 3.1-7.8%, respectively. The relative recoveries of the spiked environmental water samples at one concentration level were in the range of 77-102%. The results of the present study revealed that the proposed method is simple, fast, and uses environmentally friendly extraction solvent for the analysis of the target pesticide residues in environmental water samples.

  17. Dispersive liquid-liquid microextraction of silver nanoparticles in water using ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate.

    PubMed

    Chen, Sha; Sun, Yuanjing; Chao, Jingbo; Cheng, Liping; Chen, Yun; Liu, Jingfu

    2016-03-01

    Using the ionic liquid (IL) 1-octyl-3-methylimidazolium hexafluorophosphate as the extractant and methanol as the dispersion solvent, a dispersive liquid-liquid microextraction method was developed to extract silver nanoparticles (AgNPs) from environmental water samples. Parameters that influenced the extraction efficiency such as IL concentration, pH and extraction time were optimized. Under the optimized conditions, the highest extraction efficiency for AgNPs was above 90% with an enrichment factor of >90. The extracted AgNPs in the IL phase were identified by transmission electron microscopy and ultraviolet-visible spectroscopy, and quantified by inductively coupled plasma mass spectrometry after microwave digestion, with a detection limit of 0.01μg/L. The spiked recovery of AgNPs was 84.4% with a relative standard deviation (RSD) of 3.8% (n=6) at a spiked level of 5μg/L, and 89.7% with a RSD of 2.2% (n=6) at a spiked level of 300μg/L, respectively. Commonly existed environmental ions had a very limited influence on the extraction efficiency. The developed method was successfully applied to the analysis of AgNPs in river water, lake water, and the influent and effluent of a wastewater treatment plant, with recoveries in the range of 71.0%-90.9% at spiking levels of 0.11-4.7μg/L.

  18. The Discrepancy Between Measured and Modeled Downwelling Solar Irradiance at the Ground: Dependence on Water Vapor

    NASA Technical Reports Server (NTRS)

    Pilewski, P.; Rabbette, M.; Bergstrom, R.; Marquez, J.; Schmid, B.; Russell, P. B.

    2000-01-01

    Moderate resolution spectra of the downwelling solar irradiance at the ground in north central Oklahoma were measured during the Department of Energy Atmospheric Radiation Measurement Program Intensive Observation Period in the fall of 1997. Spectra obtained under-cloud-free conditions were compared with calculations using a coarse resolution radiative transfer model to examine the dependency of model-measurement bias on water vapor. It was found that the bias was highly correlated with water vapor and increased at a rate of 9 Wm per cm of water. The source of the discrepancy remains undetermined because of the complex dependencies of other variables, most notably aerosol optical depth, on water vapor.

  19. Some research aspects for irradiation treatment of the polluted waters in China

    NASA Astrophysics Data System (ADS)

    Jingtian, Yang; Guichun, Yun; Hongfei, Ha

    This paper is a review for some aspects of research works in the field of radiation treatment of surface and industrial polluted waters in China. These studies included: radiation-oxidized decomposition of the phenols, cyandes and pesticies etc., radiation decolourization of wastewater from dyestuff factory, radiation modification of the biodegradability of saponificated wastewater as well as radiation sterilization of surface water, hospital sewage sludge, industrial cooling- water and water flooding in oil field. In the next 5- 10 years, above-mentioned several basic application fields relating to waste irradiation will be further assisted by government departments.

  20. Spallation occurrence from polyamide materials irradiated by thermal plasma with water absorption

    NASA Astrophysics Data System (ADS)

    Nakano, Tomoyuki; Tanaka, Yasunori; Nakagawa, T.; Shinsei, N.; Uesugi, Y.; Ishijima, T.

    2016-09-01

    This paper first describes the effect of water absorption in polyamide material irradiated by thermal plasmas on the occurrence of spallation phenomena. The interaction between polyamide materials and arc plasmas occurs particularly in the low voltage circuit breaker and aerospace fields. Spallation phenomena are those in which polymer particles are ejected from polymer bulk materials irradiated by high heat flux. To confirm the effect of water absorption into the polyamide material on spallation phenomena, polyamide specimens with and without water absorption were irradiated by Ar inductively coupled thermal plasma. The results show that the polyamide specimen with water absorption ejected spallation particles, whereas the polyamide specimen without water absorption were only slightly ejected, indicating that water absorption promotes the occurrence of spallation. The cooling effects of the spallation polyamide 66 (PA66) particles ablation were also estimated in hot air to assess the arc quenching ability from the spallation particle inclusion. This estimation showed that 10 and more PA66 particles inclusion might decrease the air temperature by 3000 K effectively, which can be useful to enhance arc quenching in circuit breakers working in air.

  1. Water color affects the stratification, surface temperature, heat content, and mean epilimnetic irradiance of small lakes

    USGS Publications Warehouse

    Houser, J.N.

    2006-01-01

    The effects of water color on lake stratification, mean epilimnetic irradiance, and lake temperature dynamics were examined in small, north-temperate lakes that differed widely in water color (1.5-19.8 m -1). Among these lakes, colored lakes differed from clear lakes in the following ways: (i) the epilimnia were shallower and colder, and mean epilimnetic irradiance was reduced; (ii) the diel temperature cycles were more pronounced; (iii) whole-lake heat accumulation during stratification was reduced. The depth of the epilimnion ranged from 2.5 m in the clearest lake to 0.75 m in the most colored lake, and 91% of the variation in epilimnetic depth was explained by water color. Summer mean morning epilimnetic temperature was ???2??C cooler in the most colored lake compared with the clearest lake. In clear lakes, the diel temperature range (1.4 ?? 0.7??C) was significantly (p = 0.01) less than that in the most colored lake (2.1 ?? 1.0??C). Change in whole-lake heat content was negatively correlated with water color. Increasing water color decreased light penetration more than thermocline depth, leading to reduced mean epilimnetic irradiance in the colored lakes. Thus, in these small lakes, water color significantly affected temperature, thermocline depth, and light climate. ?? 2006 NRC.

  2. Optically Thin Liquid Water Clouds: Their Importance and Our Challenge

    NASA Technical Reports Server (NTRS)

    Turner, D. D.; Vogelmann, A. M.; Austin, R. T.; Barnard, J. C.; Cady-Pereira, K.; Chiu, J. C.; Clough, S. A.; Flynn, C.; Khaiyer, M. M.; Liljegren, J.; Johnson, K.; Lin, B.; Long, C.; Marshak, A.; Matrosov, S. Y.; McFarlane, S. A.; Miller, M.; Min, Q.; Minnis, P.; O'Hirok, W.; Wang, Z.; Wiscombe, W.

    2006-01-01

    Many of the clouds important to the Earth's energy balance, from the tropics to the Arctic, are optically thin and contain liquid water. Longwave and shortwave radiative fluxes are very sensitive to small perturbations of the cloud liquid water path (LWP) when the liquid water path is small (i.e., < g/sq m) and, thus, the radiative properties of these clouds must be well understood to capture them correctly in climate models. We review the importance of these thin clouds to the Earth's energy balance, and explain the difficulties in observing them. In particular, because these clouds are optically thin, potentially mixed-phase, and often (i.e., have large 3-D variability), it is challenging to retrieve their microphysical properties accurately. We describe a retrieval algorithm intercomparison that was conducted to evaluate the issues involved. The intercomparison included eighteen different algorithms to evaluate their retrieved LWP, optical depth, and effective radii. Surprisingly, evaluation of the simplest case, a single-layer overcast cloud, revealed that huge discrepancies exist among the various techniques, even among different algorithms that are in the same general classification. This suggests that, despite considerable advances that have occurred in the field, much more work must be done, and we discuss potential avenues for future work.

  3. Rapid screening of water soluble arsenic species in edible oils using dispersive liquid-liquid microextraction.

    PubMed

    López-García, Ignacio; Briceño, Marisol; Vicente-Martínez, Yesica; Hernández-Córdoba, Manuel

    2015-01-15

    A methodology for the non-chromatographic screening of the main arsenic species present in edible oils is discussed. Reverse dispersive liquid-liquid microextraction was used to extract water soluble arsenic compounds (inorganic arsenic, methylarsonate, dimethylarsinate and arsenobetaine) from the edible oils into a slightly acidic aqueous medium. The total arsenic content was measured in the extracts by electrothermal atomic absorption spectrometry using palladium as the chemical modifier. By repeating the measurement using cerium instead of palladium, the sum of inorganic arsenic and methylarsonate was obtained. The detection limit was 0.03 ng As per gram of oil. Data for the total and water-soluble arsenic levels of 29 samples of different origin are presented. Inorganic arsenic was not found in any of the samples marketed as edible oils.

  4. Thermally driven electrokinetic energy conversion with liquid water microjets

    NASA Astrophysics Data System (ADS)

    Lam, Royce K.; Gamlieli, Zach; Harris, Stephen J.; Saykally, Richard J.

    2015-11-01

    A goal of current energy research is to design systems and devices that can efficiently exploit waste heat and utilize solar or geothermal heat energy for electrical power generation. We demonstrate a novel technique exploiting water's large coefficient of thermal expansion, wherein modest thermal gradients produce the requisite high pressure for driving fast-flowing liquid water microjets, which can effect the direct conversion of the kinetic energy into electricity and gaseous hydrogen. Waste heat in thermoelectric generating plants and combustion engines, as well as solar and geothermal energy could be used to drive these systems.

  5. Measuring Low Concentrations of Liquid Water in Soil

    NASA Technical Reports Server (NTRS)

    Buehler, Martin

    2009-01-01

    An apparatus has been developed for measuring the low concentrations of liquid water and ice in relatively dry soil samples. Designed as a prototype of instruments for measuring the liquidwater and ice contents of Lunar and Martian soils, the apparatus could also be applied similarly to terrestrial desert soils and sands. The apparatus is a special-purpose impedance spectrometer: Its design is based on the fact that the electrical behavior of a typical soil sample is well approximated by a network of resistors and capacitors in which resistances decrease and capacitances increase (and, hence, the magnitude of impedance decreases) with increasing water content.

  6. Homogeneously aligned liquid crystal molecules on reformed poly(methyl methacrylate) via ion-beam irradiation

    NASA Astrophysics Data System (ADS)

    Jeong, Hae-Chang; Park, Hong-Gyu; Lee, Ju Hwan; Jang, Sang Bok; Oh, Byeong-Yun; Han, Jeong-Min; Seo, Dae-Shik

    2016-04-01

    We demonstrated uniform LC alignment using IB-irradiated poly(methyl methacrylate) (PMMA) as an alignment layer. We confirmed the topographical changes on PMMA caused by IB irradiation. Moreover, the wettability and chemical modification of the PMMA surface were investigated as functions of incidence angle. The results show that PMMA irradiated with IB at an incidence angle of 30° had a higher molecular polarity than PMMA irradiated with IB at other incidence angles, resulting in strong van der Waals interactions between the surface and LC molecules. The LC cells containing PMMA irradiated with IB at an incidence angle of 30° exhibited good thermal stability (180°) compared with LC cells containing conventional rubbing PI (150°). In addition, LC molecules on PMMA irradiated with IB at an incidence angle of 30° were observed to switch faster than those on conventional rubbing PI. Therefore, PMMA irradiated with IB under the optimal conditions may allow for PMMA to be applied in advanced LC devices as an alternative alignment layer.

  7. Determination of amitrole in environmental water samples with precolumn derivatization by high-performance liquid chromatography.

    PubMed

    Sun, Yan; Liu, Peng Fei; Wang, Deng; Li, Jian Qiang; Cao, Yong Song

    2009-06-10

    Amitrole is a nonselective polar herbicide that can easily pollute ground and surface waters because of its high solubility in water. A precolumn derivatization high-performance liquid chromatographic method for amitrole analysis has been developed. Derivatization of amitrole was performed with 4-chloro-3,5-dinitrobenzotrifluoride (CNBF). The derivatization conditions and the influence of elution composition on the separation were investigated. In pH 9.5 H(3)BO(3)-Na(2)B(4)O(7) media, the reaction of amitrole with CNBF was complete at 60 degrees C after 30 min. The stability of the derivative under light irradiation and room temperature in methanol-water samples was demonstrated. The derivatized amitrole was separated on a K C(18) column (250 mm x 4.6 mm, 5 microm) at room temperature, and UV detection was applied at 360 nm. The separation of derivatized amitrole was achieved within 18 min by gradient elution mode. The method correlation coefficient was 0.9995, in concentrations ranging from 1.59 to 318 mg L(-1). The detection limit of amitrole was 0.16 mg L(-1) with a signal-to-noise ratio of 3. The proposed method was applied to the quantitative determination of amitrole in environmental water with recoveries of 92.0-103.0% and RSDs of 2.22-6.26, depending on the sample investigated. This method has good accuracy and repeatability that can be used to quantify amitrole in environmental water.

  8. Temperature dependence of the structure of protein hydration water and the liquid-liquid transition.

    PubMed

    Accordino, S R; Malaspina, D C; Rodriguez Fris, J A; Alarcón, L M; Appignanesi, G A

    2012-03-01

    We study the temperature dependence of the structure and orientation of the first hydration layers of the protein lysozyme and compare it with the situation for a model homogeneous hydrophobic surface, a graphene sheet. We show that in both cases these layers are significantly better structured than bulk water. The geometrical constraint of the interface makes the water molecules adjacent to the surface lose one water-water hydrogen bond and expel the fourth neighbors away from the surface, lowering local density. We show that a decrease in temperature improves the ordering of the hydration water molecules, preserving such a geometrical effect. For the case of graphene, this favors an ice Ih-like local structuring, similar to the water-air interface but in the opposite way along the c axis of the basal plane (while the vicinal water molecules of the air interface orient a hydrogen atom toward the surface, the oxygens of the water molecules close to the graphene plane orient a lone pair in such a direction). In turn, the case of the first hydration layers of the lysozyme molecule is shown to be more complicated, but still displaying signs of both kinds of behavior, together with a tendency of the proximal water molecules to hydrogen bond to the protein both as donors and as acceptors. Additionally, we make evident the existence of signatures of a liquid-liquid transition (Widom line crossing) in different structural parameters at the temperature corresponding to the dynamic transition incorrectly referred to as "the protein glass transition."

  9. Liquid water can slip on a hydrophilic surface

    PubMed Central

    Ho, Tuan Anh; Papavassiliou, Dimitrios V.; Lee, Lloyd L.; Striolo, Alberto

    2011-01-01

    Understanding and predicting the behavior of water, especially in contact with various surfaces, is a scientific challenge. Molecular-level understanding of hydrophobic effects and their macroscopic consequences, in particular, is critical to many applications. Macroscopically, a surface is classified as hydrophilic or hydrophobic depending on the contact angle formed by a water droplet. Because hydrophobic surfaces tend to cause water slip whereas hydrophilic ones do not, the former surfaces can yield self-cleaning garments and ice-repellent materials whereas the latter cannot. The results presented herein suggest that this dichotomy might be purely coincidental. Our simulation results demonstrate that hydrophilic surfaces can show features typically associated with hydrophobicity, namely liquid water slip. Further analysis provides details on the molecular mechanism responsible for this surprising result. PMID:21911406

  10. Reversible Hydrophobic to Hydrophilic Transition in Graphene via Water Splitting Induced by UV Irradiation

    PubMed Central

    Xu, Zhemi; Ao, Zhimin; Chu, Dewei; Younis, Adnan; Li, Chang Ming; Li, Sean

    2014-01-01

    Although the reversible wettability transition between hydrophobic and hydrophilic graphene under ultraviolet (UV) irradiation has been observed, the mechanism for this phenomenon remains unclear. In this work, experimental and theoretical investigations demonstrate that the H2O molecules are split into hydrogen and hydroxyl radicals, which are then captured by the graphene surface through chemical binding in an ambient environment under UV irradiation. The dissociative adsorption of H2O molecules induces the wettability transition in graphene from hydrophobic to hydrophilic. Our discovery may hold promise for the potential application of graphene in water splitting. PMID:25245110

  11. Irradiation performance of (Th,Pu)O2 fuel under Pressurized Water Reactor conditions

    NASA Astrophysics Data System (ADS)

    Boer, B.; Lemehov, S.; Wéber, M.; Parthoens, Y.; Gysemans, M.; McGinley, J.; Somers, J.; Verwerft, M.

    2016-04-01

    This paper examines the in-pile safety performance of (Th,Pu)O2 fuel pins under simulated Pressurized Water Reactor (PWR) conditions. Both sol-gel and SOLMAS produced (Th,Pu)O2 fuels at enrichments of 7.9% and 12.8% in Pu/HM have been irradiated at SCK·CEN. The irradiation has been performed under PWR conditions (155 bar, 300 °C) in a dedicated loop of the BR-2 reactor. The loop is instrumented with flow and temperature monitors at inlet and outlet, which allow for an accurate measurement of the deposited enthalpy.

  12. Mesos-scale modeling of irradiation in pressurized water reactor concrete biological shields

    SciTech Connect

    Le Pape, Yann; Huang, Hai

    2016-01-01

    Neutron irradiation exposure causes aggregate expansion, namely radiation-induced volumetric expansion (RIVE). The structural significance of RIVE on a portion of a prototypical pressurized water reactor (PWR) concrete biological shield (CBS) is investigated by using a meso- scale nonlinear concrete model with inputs from an irradiation transport code and a coupled moisture transport-heat transfer code. RIVE-induced severe cracking onset appears to be triggered by the ini- tial shrinkage-induced cracking and propagates to a depth of > 10 cm at extended operation of 80 years. Relaxation of the cement paste stresses results in delaying the crack propagation by about 10 years.

  13. Degradation of methylene blue by radio frequency plasmas in water under ultraviolet irradiation.

    PubMed

    Maehara, Tsunehiro; Nishiyama, Kyohei; Onishi, Shingo; Mukasa, Shinobu; Toyota, Hiromichi; Kuramoto, Makoto; Nomura, Shinfuku; Kawashima, Ayato

    2010-02-15

    The degradation of methylene blue by radio frequency (RF) plasmas in water under ultraviolet (UV) irradiation was studied experimentally. When the methylene blue solution was exposed to RF plasma, UV irradiation from a mercury vapor lamp enhanced degradation significantly. A lamp without power supply also enhanced degradation since weak UV light was emitted weakly from the lamp due to the excitation of mercury vapor by stray RF power. Such an enhancement is explained by the fact that after hydrogen peroxide is produced via the recombination process of OH radicals around the plasma, OH radicals reproduced from hydrogen peroxide via the photolysis process degrade methylene blue.

  14. Impact of UV-irradiation on the formation of odorous chloroaldimines in drinking water.

    PubMed

    Freuze, Ingrid; Brosillon, Stéphan; Arlot, Jérémy; Laplanche, Alain; Tozza, Dominique; Cavard, Jacques

    2006-06-01

    In order to explain some of the possible origins of an odor episode which took place in a drinking water supply in the region of Paris (France), the impact of disinfection on the formation of odorous by-products was investigated. We have previously established that very odorous and stable chloroaldimines are formed during amino acid chlorination in conditions relevant to those of drinking water treatment. As chlorination is preceded by a UV-irradiation step, we examined here the impact of this irradiation on the formation of chloroaldimines. Irradiation (30 m W cm(-2)) of various amino acids (glycine, valine, phenylalanine) and peptides (Phe-Gly-Gly-Phe, Phe-Ala) led to a degradation of the compounds but it was negligible at the doses applied in drinking water supplies. As peptides were concerned, contrary to what we previously expected, the degradation did not involve the peptidic bond breaking: irradiation induces therefore no increase in the quantity of free amino acids, precursors of odorous chloroaldimines. However chlorination of peptides (Phe-Ala-Ala-Val, Phe-Gly-Gly-Phe and Ala-Phe) showed that chloroaldimines are also probably formed during combined amino acids chlorination.

  15. Extraction of pesticides in water samples using vortex-assisted liquid-liquid microextraction.

    PubMed

    Jia, Chunhong; Zhu, Xiaodan; Wang, Jihua; Zhao, Ercheng; He, Min; Chen, Li; Yu, Pingzhong

    2010-09-10

    A simple solvent microextraction method termed vortex-assisted liquid-liquid microextraction (VALLME) coupled with gas chromatography micro electron-capture detector (GC-microECD) has been developed and used for the pesticide residue analysis in water samples. In the VALLME method, aliquots of 30 microL toluene used as extraction solvent were directly injected into a 25 mL volumetric flask containing the water sample. The extraction solvent was dispersed into the water phase under vigorously shaking with the vortex. The parameters affecting the extraction efficiency of the proposed VALLME such as extraction solvent, vortex time, volumes of extraction solvent and salt addition were investigated. Under the optimum condition, enrichment factors (EFs) in a range of 835-1115 and limits of detection below 0.010 microg L(-1) were obtained for the determination of target pesticides in water. The calculated calibration curves provide high levels of linearity yielding correlation coefficients (r(2)) greater than 0.9958 with the concentration level ranged from 0.05 to 2.5 microg L(-1). Finally, the proposed method has been successfully applied to the determination of pesticides from real water samples and acceptable recoveries over the range of 72-106.3% were obtained.

  16. Effect of an external electric field on the escape probability in groups of multiple ion pairs in irradiated nonpolar liquids

    NASA Astrophysics Data System (ADS)

    Tachiya, M.; Hummel, A.

    1989-02-01

    The effect of an external electric field on the probability for ions to escape from recombination in groups of multiple ion pairs in irradiated nonpolar liquids is studied theoretically. It is shown analytically that the escape probability increases linearly with increasing field in the low-field limit and that the slope-to-intercept ratio in this limit is given by the same constant as that derived by Onsager for the case of a single ion pair. This result is in agreement with recent Monte Carlo results on multi-pair spurs reported by Bartczak and Hummel.

  17. How water manifests the structural regimes in ionic liquids.

    PubMed

    Singh, Akhil Pratap; Gardas, Ramesh L; Senapati, Sanjib

    2017-03-22

    Ionic liquids (ILs) are being considered as greener alternatives to the conventional organic solvents. However, highly viscous nature of ILs often limits their applications. Hence studies on IL/water binary mixtures have received tremendous attention. These mixtures exhibit much lower viscosity, but almost similar density, compressibility and other properties as that of the neat ILs, up to certain water content. Hence, determining the IL-water ratio till which the solution behaves like IL and subsequently changes to a state of solute IL dissolved in continuous water phase is of paramount importance. Noting the very different and characteristic behaviours of neat ILs and pure water over a temperature range, herein, we measured the various thermophysical properties of the binary mixtures of tetramethylguanidinium benzoate/water and tetramethylguanidinium salicylate/water with water content varying from 20 wt% to 95 wt% for a temperature range of 298 K to 343 K. The results show that similar to neat ILs, the measured densities and compressibility of these mixtures display a linear change, and viscosity decreases rapidly as temperature is increased for water content up to 50 wt%. At higher water concentrations, the measured density and compressibility exhibit nonlinear behaviour and the decrease in viscosity with increased temperature is minute, mimicking the behaviour of bulk water. MD simulations were carried out to explain the experimental observations. Simulation results show a greater temperature-induced disintegration of IL ion-water interactions in dense systems, explaining the rapid decay of the properties with temperature. The results also exhibit the presence of a neat, IL-like, H-bond mediated expanded structure in concentrated solution versus a collapsed IL structure in dilute solution.

  18. Disordering by γ-irradiation on long range order of liquid crystalline phases of cholesteryl esters

    NASA Astrophysics Data System (ADS)

    Srivastava, S. L.; Dhar, R.

    1992-10-01

    Effect of γ-irradiation from Co60 of radiation doze 50 MRad on the dielectric and thermodynamical properties of cholesteryl myristate (ChM) and cholesteryl pelargonate (ChP) have been studied by an electric impedance analyzer and differential scanning calorimeter (DSC). The mesophase transition temperatures, the enthalpy and the entropy of the transitions are depressed, and transition curves become asymmetric and wide on γ-irradiation. From the depressions in crystal to mesophase transition temperatures of ChM and ChP, we have estimated the molar fraction of impurity like fragments produced due to γ-irradiation of 50 MRad doze to be about 10%. Dielectric study of planar oriented samples of these two esters in the frequency range of 1 kHz to 10 MHz shows that due to γ-irradiation dielectric loss (ɛ`) is increased by 50 to 150% in different mesophases while dielectric constant (ɛ') is almost unchanged.

  19. Experimental basis for discriminating between thermal and athermal effects of water-filtered infrared A irradiation.

    PubMed

    Jung, Tobias; Grune, Tilman

    2012-07-01

    Considering the widespread application of water-filtered infrared A (wIRA) irradiation in medicine, cosmetics, and wellness, we have conluded that the biological effects of this electromagnetic spectrum, ranging from 780 nm to 1400 nm, have become an important focus of experimental research. Two main effects of wIRA on single cells are discussed: thermal effects, caused by absorption of energy by cellular water and the aqueous medium surrounding the irradiated sample that result in warming, and supposed athermal effects that result from a direct interaction of wIRA with cellular molecules/structures excluding water. In the following, we discuss different experimental setups and highlight some cellular responses to thermal and athermal wIRA effects, as well as the experimental problems in differentiating between them. © 2012 New York Academy of Sciences.

  20. Study of some liquid crystalline fatty acid samples subjected to thermal neutron irradiation

    NASA Astrophysics Data System (ADS)

    Ghelmez, Mihaela A.; Slavnicu, Elena; Slavnicu, Dan; Sterian, Andreea R.; Dumitru, Bogdan

    2003-11-01

    This paper presents the effect of thermal neutrons irradiation on some properties of one of the most common long-chain fatty acids, found in combined form in natural animal and vegetable fats, the stearic acid, with role in the biological membrane. Microscopic aspect, electric current and optical properties under laser beam change by irradiation. These changes can offer information both for biology and technique.

  1. Improvement in properties of coal water slurry by combined use of new additive and ultrasonic irradiation.

    PubMed

    Guo, Zhaobing; Feng, Ruo; Zheng, Youfei; Fu, Xiaoru

    2007-07-01

    Coal water slurry (CWS) was prepared with a newly developed additive from naphthalene oil. The effects of ultrasonic irradiation on coal particle size distribution (PSD), adsorption behavior of additive in coal particles and the characteristics of CWS were investigated. Results showed that ultrasonic irradiation led to a higher proportion of fine coal in CWS and increased the saturated adsorption amount of additive in coal particles. In addition, the rheological behavior and static stability of CWS irradiated by ultrasonic wave were remarkably improved. The changes on viscosity of CWS containing 1% and 2% additive are qualitatively different with the increasing sonication time studied. The reason for the different effect of sonication time on CWS viscosity is presented in this study.

  2. Tuning the Liquid-Liquid Transition by Modulating the Hydrogen-Bond Angular Flexibility in a Model for Water

    NASA Astrophysics Data System (ADS)

    Smallenburg, Frank; Sciortino, Francesco

    2015-07-01

    We propose a simple extension of the well known ST2 model for water [F. H. Stillinger and A. Rahman, J. Chem. Phys. 60, 1545 (1974)] that allows for a continuous modification of the hydrogen-bond angular flexibility. We show that the bond flexibility affects the relative thermodynamic stability of the liquid and of the hexagonal (or cubic) ice. On increasing the flexibility, the liquid-liquid critical point, which in the original ST2 model is located in the no-man's land (i.e., the region where ice is the thermodynamically stable phase) progressively moves to a temperature where the liquid is more stable than ice. Our study definitively proves that the liquid-liquid transition in the ST2 model is a genuine phenomenon, of high relevance in all tetrahedral network-forming liquids, including water.

  3. IR and Raman spectra of liquid water: theory and interpretation.

    PubMed

    Auer, B M; Skinner, J L

    2008-06-14

    IR and Raman (parallel- and perpendicular-polarized) spectra in the OH stretch region for liquid water were measured some years ago, but their interpretation is still controversial. In part, this is because theoretical calculation of such spectra for a neat liquid presents a formidable challenge due to the coupling between vibrational chromophores and the effects of motional narrowing. Recently we proposed an electronic structure/molecular dynamics method for calculating spectra of dilute HOD in liquid D(2)O, which relied on ab initio calculations on clusters to provide a map from nuclear coordinates of the molecules in the liquid to OH stretch frequencies, transition dipoles, and polarizabilities. Here we extend this approach to the calculation of couplings between chromophores. From the trajectories of the fluctuating local-mode frequencies, transition moments, and couplings, we use our recently developed time-averaging approximation to calculate the line shapes. Our results are in good agreement with experiment for the IR and Raman line shapes, and capture the significant differences among them. Our analysis shows that while the coupling between chromophores is relatively modest, it nevertheless produces delocalization of the vibrational eigenstates over up to 12 chromophores, which has a profound effect on the spectroscopy. In particular, our results demonstrate that the peak in the parallel-polarized Raman spectrum at about 3250 wavenumbers is collective in nature.

  4. Ab initio liquid water from PBE0 hybrid functional simulations

    NASA Astrophysics Data System (ADS)

    Li, Zhaofeng; Wu, Xifan; Car, Roberto

    2010-03-01

    For reasons of computational efficiency, so far most ab initio molecular dynamics simulations of liquid water have been based on semi-local density functional approximations, such as PBE and BLYP. These approaches yield a liquid structure that, albeit qualitatively correct, is overstructured compared to experiment, even after nuclear quantum effects have been taken into account.footnotetextJ. A. Morrone and R. Car, Phys. Rev. Lett. 101, 017801(2008) A major cause of this inaccuracy is the delocalization error associated to semi-local density functional approximations, which, as a consequence, overestimate slightly the hydrogen bond strength in the liquid. In this work we adopt the PBE0 hybrid functional approximation, which, by mixing a fraction of exact (Hartree-Fock) exchange, reduces significantly the delocalization error of semi-local functionals. Our approach is based on a numerically efficient order-N implementation of exact exchange.footnotetextX. Wu, A. Selloni, and R. Car, Phys. Rev. B 79, 085102(2009) We find that PBE0 systematically improves the agreement of the simulated liquid with experiment. Our conclusion is substantiated by the calculated radial distribution functions, H-bond statistics, and molecular dipole distribution.

  5. Relationship between structural order and the anomalies of liquid water.

    PubMed

    Errington, J R; Debenedetti, P G

    2001-01-18

    In contrast to crystalline solids--for which a precise framework exists for describing structure--quantifying structural order in liquids and glasses has proved more difficult because even though such systems possess short-range order, they lack long-range crystalline order. Some progress has been made using model systems of hard spheres, but it remains difficult to describe accurately liquids such as water, where directional attractions (hydrogen bonds) combine with short-range repulsions to determine the relative orientation of neighbouring molecules as well as their instantaneous separation. This difficulty is particularly relevant when discussing the anomalous kinetic and thermodynamic properties of water, which have long been interpreted qualitatively in terms of underlying structural causes. Here we attempt to gain a quantitative understanding of these structure-property relationships through the study of translational and orientational order in a models of water. Using molecular dynamics simulations, we identify a structurally anomalous region--bounded by loci of maximum orientational order (at low densities) and minimum translational order (at high densities)--in which order decreases on compression, and where orientational and translational order are strongly coupled. This region encloses the entire range of temperatures and densities for which the anomalous diffusivity and thermal expansion coefficient of water are observed, and enables us to quantify the degree of structural order needed for these anomalies to occur. We also find that these structural, kinetic and thermodynamic anomalies constitute a cascade: they occur consecutively as the degree of order is increased.

  6. Liquid water simulations with the density fragment interaction approach.

    PubMed

    Hu, Xiangqian; Jin, Yingdi; Zeng, Xiancheng; Hu, Hao; Yang, Weitao

    2012-06-07

    We reformulate the density fragment interaction (DFI) approach [Fujimoto and Yang, J. Chem. Phys., 2008, 129, 054102.] to achieve linear-scaling quantum mechanical calculations for large molecular systems. Two key approximations are developed to improve the efficiency of the DFI approach and thus enable the calculations for large molecules: the electrostatic interactions between fragments are computed efficiently by means of polarizable electrostatic-potential-fitted atomic charges; and frozen fragment pseudopotentials, similar to the effective fragment potentials that can be fitted from interactions between small molecules, are employed to take into account the Pauli repulsion effect among fragments. Our reformulated and parallelized DFI method demonstrates excellent parallel performance based on the benchmarks for the system of 256 water molecules. Molecular dynamics simulations for the structural properties of liquid water also show a qualitatively good agreement with experimental measurements including the heat capacity, binding energy per water molecule, and the radial distribution functions of atomic pairs of O-O, O-H, and H-H. With this approach, large-scale quantum mechanical simulations for water and other liquids become feasible.

  7. Selective extraction of emerging contaminants from water samples by dispersive liquid-liquid microextraction using functionalized ionic liquids.

    PubMed

    Yao, Cong; Li, Tianhao; Twu, Pamela; Pitner, William R; Anderson, Jared L

    2011-03-25

    Functionalized ionic liquids containing the tris(pentafluoroethyl)trifluorophosphate (FAP) anion were used as extraction solvents in dispersive liquid-liquid microextraction (DLLME) for the extraction of 14 emerging contaminants from water samples. The extraction efficiencies and selectivities were compared to those of an in situ IL DLLME method which uses an in situ metathesis reaction to exchange 1-butyl-3-methylimidazolium chloride (BMIM-Cl) to 1-butyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide (BMIM-NTf(2)). Compounds containing tertiary amine functionality were extracted with high selectivity and sensitivity by the 1-(6-amino-hexyl)-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate (HNH(2)MPL-FAP) IL compared to other FAP-based ILs and the BMIM-NTf(2) IL. On the other hand, polar or acidic compounds without amine groups exhibited higher enrichment factors using the BMIM-NTf(2) IL. The detection limits for the studied analytes varied from 0.1 to 55.1 μg/L using the traditional IL DLLME method with the HNH(2)MPL-FAP IL as extraction solvent, and from 0.1 to 55.8 μg/L using in situ IL DLLME method with BMIM-Cl+LiNTf(2) as extraction solvent. A 93-fold decrease in the detection limit of caffeine was observed when using the HNH(2)MPL-FAP IL compared to that obtained using in situ IL DLLME method. Real water samples including tap water and creek water were analyzed with both IL DLLME methods and yielded recoveries ranging from 91% to 110%.

  8. Using LiF:Mg,Cu,P TLDs to estimate the absorbed dose to water in liquid water around an 192Ir brachytherapy source.

    PubMed

    Lucas, P Avilés; Aubineau-Lanièce, I; Lourenço, V; Vermesse, D; Cutarella, D

    2014-01-01

    The absorbed dose to water is the fundamental reference quantity for brachytherapy treatment planning systems and thermoluminescence dosimeters (TLDs) have been recognized as the most validated detectors for measurement of such a dosimetric descriptor. The detector response in a wide energy spectrum as that of an (192)Ir brachytherapy source as well as the specific measurement medium which surrounds the TLD need to be accounted for when estimating the absorbed dose. This paper develops a methodology based on highly sensitive LiF:Mg,Cu,P TLDs to directly estimate the absorbed dose to water in liquid water around a high dose rate (192)Ir brachytherapy source. Different experimental designs in liquid water and air were constructed to study the response of LiF:Mg,Cu,P TLDs when irradiated in several standard photon beams of the LNE-LNHB (French national metrology laboratory for ionizing radiation). Measurement strategies and Monte Carlo techniques were developed to calibrate the LiF:Mg,Cu,P detectors in the energy interval characteristic of that found when TLDs are immersed in water around an (192)Ir source. Finally, an experimental system was designed to irradiate TLDs at different angles between 1 and 11 cm away from an (192)Ir source in liquid water. Monte Carlo simulations were performed to correct measured results to provide estimates of the absorbed dose to water in water around the (192)Ir source. The dose response dependence of LiF:Mg,Cu,P TLDs with the linear energy transfer of secondary electrons followed the same variations as those of published results. The calibration strategy which used TLDs in air exposed to a standard N-250 ISO x-ray beam and TLDs in water irradiated with a standard (137)Cs beam provided an estimated mean uncertainty of 2.8% (k = 1) in the TLD calibration coefficient for irradiations by the (192)Ir source in water. The 3D TLD measurements performed in liquid water were obtained with a maximum uncertainty of 11% (k = 1) found at 1 cm

  9. Using LiF:Mg,Cu,P TLDs to estimate the absorbed dose to water in liquid water around an {sup 192}Ir brachytherapy source

    SciTech Connect

    Lucas, P. Avilés Aubineau-Lanièce, I.; Lourenço, V.; Vermesse, D.; Cutarella, D.

    2014-01-15

    Purpose: The absorbed dose to water is the fundamental reference quantity for brachytherapy treatment planning systems and thermoluminescence dosimeters (TLDs) have been recognized as the most validated detectors for measurement of such a dosimetric descriptor. The detector response in a wide energy spectrum as that of an{sup 192}Ir brachytherapy source as well as the specific measurement medium which surrounds the TLD need to be accounted for when estimating the absorbed dose. This paper develops a methodology based on highly sensitive LiF:Mg,Cu,P TLDs to directly estimate the absorbed dose to water in liquid water around a high dose rate {sup 192}Ir brachytherapy source. Methods: Different experimental designs in liquid water and air were constructed to study the response of LiF:Mg,Cu,P TLDs when irradiated in several standard photon beams of the LNE-LNHB (French national metrology laboratory for ionizing radiation). Measurement strategies and Monte Carlo techniques were developed to calibrate the LiF:Mg,Cu,P detectors in the energy interval characteristic of that found when TLDs are immersed in water around an{sup 192}Ir source. Finally, an experimental system was designed to irradiate TLDs at different angles between 1 and 11 cm away from an {sup 192}Ir source in liquid water. Monte Carlo simulations were performed to correct measured results to provide estimates of the absorbed dose to water in water around the {sup 192}Ir source. Results: The dose response dependence of LiF:Mg,Cu,P TLDs with the linear energy transfer of secondary electrons followed the same variations as those of published results. The calibration strategy which used TLDs in air exposed to a standard N-250 ISO x-ray beam and TLDs in water irradiated with a standard{sup 137}Cs beam provided an estimated mean uncertainty of 2.8% (k = 1) in the TLD calibration coefficient for irradiations by the {sup 192}Ir source in water. The 3D TLD measurements performed in liquid water were obtained with a

  10. One-dimensional model for water and aqueous solutions. I. Pure liquid water

    NASA Astrophysics Data System (ADS)

    Ben-Naim, Arieh

    2008-01-01

    Two simplified one-dimensional models for waterlike particles are studied. One is referred to as the primitive model which is a simplified version of a model introduced by Ben-Naim in 1992 [Statistical Thermodynamics for Chemists and Biochemists (Plenum, New York, 1992)]. The second, referred to as the primitive cluster model, is a simplified version of the model used by Lovett and Ben-Naim in 1969 [J. Chem. Phys. 51, 3108 (1969)]. The two models are shown to be nearly equivalent and both exhibit some of the most characteristic behavior of liquid water. It is argued that a key feature of the molecular interactions—the correlation between the strong binding energy and low local density—is essential for the manifestation of the anomalous behavior of liquid water. It is also essential for the understanding of the outstanding behavior of liquid water.

  11. Liquid water and organics in Comets: implications for exobiology

    NASA Astrophysics Data System (ADS)

    Wickramasinghe, J. T.; Wickramasinghe, N. C.; Wallis, M. K.

    2009-10-01

    Liquid water in comets, once considered impossible, now appears to be almost certain. New evidence has come from the discovery of clay minerals in comet Tempel 1, which compliments the indirect evidence in aqueous alteration of carbonaceous chondrites. Infrared spectral indication of clay is confirmed by modelling data in the 8-40 μm and 8-12 μm wavebands on the basis of mixtures of clays and organics. Radiogenic heating producing liquid water cores in freshly formed comets appears more likely on current evidence for solar system formation. A second possibility investigated here is transient melting in comets in the inner solar system, where thin crusts of asphalt-like material, formed due to solar processing and becoming hot in the daytime, can cause melting of sub-surface icy material a few centimetres deep. Supposing comets were seeded with microbes at the time of their formation from pre-solar material, there would be plenty of time for exponential amplification and evolution within the liquid interior and in the transient ponds or lakes formed as the outer layers are stripped away via sublimation.

  12. Liquid Water and Organics in Comets: Implications for Exobiology

    NASA Astrophysics Data System (ADS)

    Wickramasinghe, J. T.; Wickramasinghe, N. C.; Wallis, M. K.

    Liquid water in comets, once considered impossible, now appears to be almost certain. New evidence has come from the discovery of clay minerals in comet Tempel 1, which complements the indirect evidence in aqueous alteration of carbonaceous chondrites. Infrared spectral indication of clay is confirmed by modelling data in the 8-40 μm and 8-12 μm wavebands on the basis of mixtures of clays and organics. Radiogenic heating producing liquid water cores in freshly formed comets appears more likely on current evidence for solar system formation. A second possibility investigated here is transient melting in comets in the inner solar system, where thin crusts of asphalt-like material, formed due to solar processing and becoming hot in the daytime, can cause melting of sub-surface icy material a few centimetres deep. Supposing comets were seeded with microbes at the time of their formation from pre-solar material, there would be plenty of time for exponential amplification and evolution within the liquid interior and in the transient ponds or lakes formed as the outer layers are stripped away via sublimation.

  13. Fractionation of sugar cane with hot, compressed, liquid water

    SciTech Connect

    Allen, S.G.; Kam, L.C.; Zemann, A.J.; Antal, M.J. Jr.

    1996-08-01

    Sugar-cane bagasse and leaves (10--15 g oven-dry basis) were fractionated without size reduction by a rapid (45 s to 4 min), immersed percolation using only hot (190--230 C), compressed (P > P{sub sat}), liquid water (0.6--1.2 kg). Over 50% of the biomass could be solubilized. All of the hemicellulose, together with much of the acid-insoluble lignin in the bagasse (>60%), was solubilized, while less than 10% of the cellulose entered the liquid phase. Moreover, recovery of the hemicellulose as monomeric sugars (after a mild posthydrolysis) exceeded 80%. Less than 5% of the hemicellulose was converted to furfural. Percolation beyond that needed to immerse the biomass in hot liquid water did not result in increased solubilization. The yield of lignocellulosic residue was also not sensitive to the form of the sugar cane used (bagasse or leaves) or its moisture content (8--50%). Commercial applications for this fractionation process include the pretreatment of lignocellulosics for bioconversion to ethanol and the production of pulp and paper products.

  14. Influence of microwave irradiation on the mass-transfer kinetics of propylbenzene in reversed-phase liquid chromatography

    SciTech Connect

    Galinada, Wilmer; Kaczmarski, Krzysztof; Guiochon, Georges A

    2005-09-01

    The effect of microwave irradiation on the kinetics of mass transfer in reversed-phase liquid chromatography (RPLC) was studied by measuring its influence on the band profile of propylbenzene in a C{sub 18}-silica column eluted with an aqueous solution of methanol and placed inside a microwave oven. The elution peaks were measured by the pulse-response method, under linear conditions. The amount of microwave energy induced into the column was varied based on the microwave input power. The experimental data were analyzed using the conventional method of moment analysis and the lumped pore diffusion model. With input powers of 15 and 30 W, the effluent temperatures were 25 {+-} 1 and 30 {+-} 1 C, respectively. The effect of microwave irradiation on the mass transfer of the studied solute was determined by comparing the band profiles obtained under the same experimental conditions, at the same temperature, with and without irradiation. The values of the intraparticle diffusion coefficient, D{sub e}, measured with microwave irradiation were ca. 20% higher than those obtained without irradiation. Derived from the method of moments, the values of D{sub e} at 15 W (25 {+-} 1 C) and 0 W (25 {+-} 1 C) were 8.408 x 10{sup -6} cm{sup 2} s{sup -1} and 6.947 x 10{sup -6} cm{sup 2} s{sup -1}, respectively, while these values at 30 W (30 {+-} 1 C) and 0 W (30 {+-} 1 C) were 9.389 x 10{sup -6} cm{sup 2} s{sup -1} and 7.848 x 10{sup -6} cm{sup 2} s{sup -1}, respectively. The values of the surface diffusivity, D{sub S}, also increased with increasing power of the microwave irradiation. It is assumed that the increase in intraparticle diffusion for propylbenzene was caused by the molecular excitation of the organic modifier that has a higher dielectric loss than the solute. The values of D{sub e} were also analyzed and determined using the POR model. There was an excellent agreement between the results of the two independent methods. These preliminary results suggest that microwave

  15. Meteoritic strikes and liquid water pools on Titan

    NASA Astrophysics Data System (ADS)

    Artemieva, Natalia; Lunine, Jonathan

    Impact cratering must be an important process on Titan, since the airless icy satellites of the saturnian system exhibit high crater densities. However, Titan's thick atmosphere efficiently decelerates all comets smaller than 2-3 km in diameter. The resulting airblasts may heat an atmosphere locally and distribute cometary materials around Titan. We performed 3D numerical simulations of cometary impacts on Titan varying the comet size from 3 to 30 km and the crust thickness -from 10 km (ancient Titan) to 50 km (the last 1 Gyr). The surface temperature is 94 K, the water mantle is at 273 K with a calculated crustal thermal gradient in between. Cratering processes on Titan are mainly defined by the thickness of its crust. Even the smallest comets easily breached an ancient Titan's crust, delivering huge amount of water (both, molten crust and underlying ocean). The shape of these craters differs substantially from standard complex craters: a central uplift does not emerge; the rim is substantially eroded by liquid flows. Moreover, any crater relaxes quickly in the high-temperature (hence, low-viscosity) ice. Indeed, recent Cassini observations revealed a substantial dearth of impact craters on the surface with an approximate surface age of < 1 Gyr. Under modern conditions only < 10-km-diameter comets produce a crater in ice, while larger comets breach the crust creating an open water pool. The freezing time of an impact pool with a thickness H [km] is 26H2 [kyr]. If ammonia is present at non-negligible levels then the time for complete freezing could be significantly longer. Comparison of the impact rates and the cooling time of water shows that a persistent surface water layer on Titan does not exist for the present thermal conditions and for the present impact rate in saturnian system. Nonetheless, a non-negligible fraction of Titan's hydrocarbon (including ethane) deposits might have been exposed to liquid water on the surface over Titan's history. The interaction

  16. A "First Principles" Potential Energy Surface for Liquid Water from VRT Spectroscopy of Water Clusters

    SciTech Connect

    Goldman, N; Leforestier, C; Saykally, R J

    2004-05-25

    We present results of gas phase cluster and liquid water simulations from the recently determined VRT(ASP-W)III water dimer potential energy surface. VRT(ASP-W)III is shown to not only be a model of high ''spectroscopic'' accuracy for the water dimer, but also makes accurate predictions of vibrational ground-state properties for clusters up through the hexamer. Results of ambient liquid water simulations from VRT(ASP-W)III are compared to those from ab initio Molecular Dynamics, other potentials of ''spectroscopic'' accuracy, and to experiment. The results herein represent the first time that a ''spectroscopic'' potential surface is able to correctly model condensed phase properties of water.

  17. Liquid-liquid coexistence and crystallization in supercooled ST2 water

    NASA Astrophysics Data System (ADS)

    Martelli, Fausto; Palmer, Jeremy; Debenedetti, Pablo; Car, Roberto

    2014-03-01

    We have computed the free energy landscape of ST2 water in the supercooled regime (228.6 K and 2.4 kbar) using several state-of-the-art computational techniques, including umbrella sampling and metadynamics. Such results conclusively demonstrate coexistence between two liquid phases, a high-density liquid (HDL) and a low-density liquid (HDL), which are metastable with respect to cubic ice. We show that the three phases have distinct structural features characterized by the local structure index and ring statistics. We also find that ice nucleation, should it occur, does so from the low-density liquid. Interestingly, we find that the number of 6-member rings increases monotonically along the path from HDL to LDL, while non-monotonic behavior is observed near the saddle point along the LDL-ice Ic path. This behavior indicates a complex re-arrangement of the H-bond network, followed by progressive crystallization. DOE: DE-SC0008626 (F. M. and R.C.)

  18. Shock wave initiated by an ion passing through liquid water

    NASA Astrophysics Data System (ADS)

    Surdutovich, Eugene; Solov'Yov, Andrey V.

    2010-11-01

    We investigate the shock wave produced by an energetic ion in liquid water. This wave is initiated by a rapid energy loss when the ion moves through the Bragg peak. The energy is transferred from the ion to secondary electrons, which then transfer it to the water molecules. The pressure in the overheated water increases by several orders of magnitude and drives a cylindrical shock wave on a nanometer scale. This wave eventually weakens as the front expands further; but before that, it may contribute to DNA damage due to large pressure gradients developed within a few nanometers from the ion’s trajectory. This mechanism of DNA damage may be a very important contribution to the direct chemical effects of low-energy electrons and holes.

  19. Thermodynamic properties of liquid water from a polarizable intermolecular potential.

    PubMed

    Yigzawe, Tesfaye M; Sadus, Richard J

    2013-01-28

    Molecular dynamics simulation results are reported for the pressure, isothermal pressure coefficient, thermal expansion coefficient, isothermal and adiabatic compressibilities, isobaric and isochoric heat capacities, Joule-Thomson coefficient and speed of sound of liquid water using a polarizable potential [Li et al., J. Chem. Phys. 127, 154509 (2007)]. These properties were obtained for a wide range of temperatures and pressures at a common liquid density using the treatment of Lustig [J. Chem. Phys. 100, 3048 (1994)] and Meier and Kabelac [J. Chem. Phys. 124, 064104 (2006)], whereby thermodynamic state variables are expressible in terms of phase-space functions determined directly from molecular dynamics simulations. Comparison with experimental data indicates that the polarizable potential can be used to predict most thermodynamic properties with a very good degree of accuracy.

  20. Development of a liquid-fed water resistojet

    NASA Technical Reports Server (NTRS)

    Morren, W. Earl; Stone, James R.

    1988-01-01

    A concept for a forced-flow once-through water vaporizer for application to resistojet thrusters was evaluated as an element of a laboratory model thruster and tested to investigate its operating characteristics. The vaporizer design concept employs flow swirling to attach the liquid flow to the boiler chamber wall, providing for separation of the two liquid phases. This vaporizer was modified with a nozzle and a centrally-located heater to facilitatite vaporization, superheating, and expansion of the propellant, allowing it to function as a resistojet. Performance was measured at thrust levels ranging from 170 to 360 mN and at power levels ranging from 443 to 192 W. Maximum measured specific impulse was 192 sec.

  1. Development of a liquid-fed water resistojet

    NASA Technical Reports Server (NTRS)

    Morren, W. Earl; Stone, James R.

    1988-01-01

    A concept for a forced-flow once-through water vaporizer for application to resistojet thrusters was evaluated as an element of a laboratory model thruster and tested to investigate its operating characteristics. The vaporizer design concept employs flow swirling to attach the liquid flow to the boiler chamber wall, providing for separation of the two liquid phases. This vaporizer was modified with a nozzle and a centrally-located heater to facilitate vaporization, superheating, and expansion of the propellant, allowing it to function as a resistojet. Performance was measured at thrust levels ranging from 170 to 360 mN and at power levels ranging from 443 to 192 W. Maximum measured specific impulse was 192 sec.

  2. Jeju ground water containing vanadium induced immune activation on splenocytes of low dose γ-rays-irradiated mice.

    PubMed

    Ha, Danbee; Joo, Haejin; Ahn, Ginnae; Kim, Min Ju; Bing, So Jin; An, Subin; Kim, Hyunki; Kang, Kyung-goo; Lim, Yoon-Kyu; Jee, Youngheun

    2012-06-01

    Vanadium, an essential micronutrient, has been implicated in controlling diabetes and carcinogenesis and in impeding reactive oxygen species (ROS) generation. γ-ray irradiation triggers DNA damage by inducing ROS production and causes diminution in radiosensitive immunocytes. In this study, we elucidate the immune activation capacities of Jeju water containing vanadium on immunosuppression caused by γ-ray irradiation, and identify its mechanism using various low doses of NaVO(3). We examined the intracellular ROS generation, DNA damage, cell proliferation, population of splenocytes, and cytokine/antibody profiles in irradiated mice drinking Jeju water for 180 days and in non-irradiated and in irradiated splenocytes both of which were treated with NaVO(3). Both Jeju water and 0.245 μM NaVO(3) attenuated the intracellular ROS generation and DNA damage in splenocytes against γ-ray irradiation. Splenocytes were significantly proliferated by the long-term intake of Jeju water and by 0.245 μM NaVO(3) treatment, and the expansion of B cells accounted for the increased number of splenocytes. Also, 0.245 μM NaVO(3) treatment showed the potency to amplify the production of IFN-γ and total IgG in irradiated splenocytes, which correlated with the expansion of B cells. Collectively, Jeju water containing vanadium possesses the immune activation property against damages caused by γ-irradiation.

  3. Ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction for the separation and determination of estrogens in water samples by high-performance liquid chromatography with fluorescence detection.

    PubMed

    Zhang, Rui; Wang, Chuanliu; Yue, Qiaohong; Zhou, Tiecheng; Li, Na; Zhang, Hanqi; Hao, Xiaoke

    2014-11-01

    An ionic liquid foam floatation coupled with ionic liquid dispersive liquid-liquid microextraction method was proposed for the extraction and concentration of 17-α-estradiol, 17-β-estradiol-benzoate, and quinestrol in environmental water samples by high-performance liquid chromatography with fluorescence detection. 1-Hexyl-3-methylimidazolium tetrafluoroborate was applied as foaming agent in the foam flotation process and dispersive solvent in microextraction. The introduction of the ion-pairing and salting-out agent NH4 PF6 was beneficial to the improvement of recoveries for the hydrophobic ionic liquid phase and analytes. Parameters of the proposed method including concentration of 1-hexyl-3-methylimidazolium tetrafluoroborate, flow rate of carrier gas, floatation time, types and concentration of ionic liquids, salt concentration in samples, extraction time, and centrifugation time were evaluated. The recoveries were between 98 and 105% with relative standard deviations lower than 7% for lake water and well water samples. The isolation of the target compounds from the water was found to be efficient, and the enrichment factors ranged from 4445 to 4632. This developing method is free of volatile organic solvents compared with regular extraction. Based on the unique properties of ionic liquids, the application of foam floatation, and dispersive liquid-liquid microextraction was widened. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Size-Resolved Photoelectron Anisotropy of Gas Phase Water Clusters and Predictions for Liquid Water

    NASA Astrophysics Data System (ADS)

    Hartweg, Sebastian; Yoder, Bruce L.; Garcia, Gustavo A.; Nahon, Laurent; Signorell, Ruth

    2017-03-01

    We report the first measurements of size-resolved photoelectron angular distributions for the valence orbitals of neutral water clusters with up to 20 molecules. A systematic decrease of the photoelectron anisotropy is found for clusters with up to 5-6 molecules, and most remarkably, convergence of the anisotropy for larger clusters. We suggest the latter to be the result of a local short-range scattering potential that is fully described by a unit of 5-6 molecules. The cluster data and a detailed electron scattering model are used to predict the anisotropy of slow photoelectrons in liquid water. Reasonable agreement with experimental liquid jet data is found.

  5. Characterization of modified PVDF membrane by gamma irradiation for non-potable water reuse.

    PubMed

    Lim, Seung Joo; Kim, Tak-Hyun; Shin, In Hwan

    2015-01-01

    Poly(vinylidene fluorine) (PVDF) membranes were grafted by gamma-ray irradiation and were sulfonated by sodium sulfite to modify the surface of the membranes. The characteristics of the modified PVDF membranes were evaluated by the data of Fourier transform infrared (FT-IR), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscope (FE-SEM), the contact angle of the membrane surface and the water permeability. From the results of FT-IR, XPS and FE-SEM, it was shown that the modified membranes were successfully grafted by gamma-ray irradiation and were sulfonated. The content of oxygen and sulfur increased with the monomer concentration, while the content of fluorine sharply decreased. The pore size of the modified membranes decreased after gamma-ray irradiation. The contact angle and the water permeability showed that the hydrophilicity of the modified membranes played a role in determining the membrane performance. The feasibility study of the modified PVDF membranes for using non-potable water reuse were carried out using a laboratory-scale microfiltration system. Grey wastewater was used as the influent in the filtration unit, and permeate quality satisfied non-potable water reuse guidelines in the Republic of Korea.

  6. Gradual modification of ITO particle's crystal structure and optical properties by pulsed UV laser irradiation in a free liquid jet.

    PubMed

    Lau, Marcus; Straube, Thomas; Aggarwal, A Vikas; Hagemann, Ulrich; de Oliveira Viestel, Bernardo; Hartmann, Nils; Textor, Torsten; Lutz, Harald; Gutmann, Jochen S; Barcikowski, Stephan

    2017-05-09

    Indium tin oxide (ITO) particle coatings are known for high transparency in the visible, good conductive properties and near-infrared absorption. These properties depend on ITO particle's stoichiometric composition, defects and size. Here we present a method to gradually change ITO particle's optical properties by a simple and controlled laser irradiation process. The defined irradiation process and controlled energy dose input allows one to engineer the absorption and transmission of coatings made from these particles. We investigate the role of the surrounding solvent, influence of laser fluence and the specific energy dose targeting modification of the ITO particle's morphology and chemistry by stepwise laser irradiation in a free liquid jet. TEM, SEM, EDX, XPS, XRD and Raman are used to elucidate the structural, morphological and chemical changes of the laser-induced ITO particles. On the basis of these results the observed modification of the optical properties is tentatively attributed to chemical changes, e.g. laser-induced defects or partial reduction.

  7. Reinforcement of natural rubber/high density polyethylene blends with electron beam irradiated liquid natural rubber-coated rice husk

    NASA Astrophysics Data System (ADS)

    Chong, E. L.; Ahmad, Ishak; Dahlan, H. M.; Abdullah, Ibrahim

    2010-08-01

    Coating of rice husk (RH) surface with liquid natural rubber (LNR) and exposure to electron beam irradiation in air were studied. FTIR analysis on the LNR-coated RH (RHR) exposed to electron beam (EB) showed a decrease in the double bonds and an increase in hydroxyl and hydrogen bonded carbonyl groups arising from the chemical interaction between the active groups on RH surface with LNR. The scanning electron micrograph showed that the LNR formed a coating on the RH particles which transformed to a fine and clear fibrous layer at 20 kGy irradiation. The LNR film appeared as patches at 50 kGy irradiation due to degradation of rubber. Composites of natural rubber (NR)/high density polyethylene (HDPE)/RHR showed an optimum at 20-30 kGy dosage with the maximum stress, tensile modulus and impact strength of 6.5, 79 and 13.2 kJ/m 2, respectively. The interfacial interaction between the modified RH and TPNR matrix had improved on exposure of RHR to e-beam at 20-30 kGy dosage.

  8. Determination of trace lead in biological and water samples with dispersive liquid-liquid microextraction preconcentration.

    PubMed

    Liang, Pei; Sang, Hongbo

    2008-09-01

    A new method for the determination of trace lead was developed by dispersive liquid-liquid microextraction preconcentration and graphite furnace atomic absorption spectrometry. In the proposed approach, 1-phenyl-3-methyl-4-benzoyl-5-pyrazolone (PMBP) was used as a chelating agent, and carbon tetrachloride and ethanol were selected as extraction and dispersive solvents. Some factors influencing the extraction efficiency of lead and its subsequent determination, including extraction and dispersive solvent type and volume, pH of sample solution, concentration of the chelating agent, and extraction time, were studied and optimized. Under the optimum conditions, the enrichment factor of this method for lead was reached at 78. The detection limit for lead was 39 ng L(-1) (3 sigma), and the relative standard deviation (RSD) was 3.2% (n=7, c=10 ng mL(-1)). The method was successfully applied to the determination of trace amounts of lead in human urine and water samples.

  9. Interfacial thermodynamics of water and six other liquid solvents.

    PubMed

    Pascal, Tod A; Goddard, William A

    2014-06-05

    We examine the thermodynamics of the liquid-vapor interface by direct calculation of the surface entropy, enthalpy, and free energy from extensive molecular dynamics simulations using the two-phase thermodynamics (2PT) method. Results for water, acetonitrile, cyclohexane, dimethyl sulfoxide, hexanol, N-methyl acetamide, and toluene are presented. We validate our approach by predicting the interfacial surface tensions (IFT--excess surface free energy per unit area) in excellent agreement with the mechanical calculations using Kirkwood-Buff theory. Additionally, we evaluate the temperature dependence of the IFT of water as described by the TIP4P/2005, SPC/Ew, TIP3P, and mW classical water models. We find that the TIP4P/2005 and SPC/Ew water models do a reasonable job of describing the interfacial thermodynamics; however, the TIP3P and mW are quite poor. We find that the underprediction of the experimental IFT at 298 K by these water models results from understructured surface molecules whose binding energies are too weak. Finally, we performed depth profiles of the interfacial thermodynamics which revealed long tails that extend far into what would be considered bulk from standard Gibbs theory. In fact, we find a nonmonotonic interfacial free energy profile for water, a unique feature that could have important consequences for the absorption of ions and other small molecules.

  10. Gas hydrate inhibition by perturbation of liquid water structure

    NASA Astrophysics Data System (ADS)

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Lee, Kun-Hong

    2015-06-01

    Natural gas hydrates are icy crystalline materials that contain hydrocarbons, which are the primary energy source for this civilization. The abundance of naturally occurring gas hydrates leads to a growing interest in exploitation. Despite their potential as energy resources and in industrial applications, there is insufficient understanding of hydrate kinetics, which hinders the utilization of these invaluable resources. Perturbation of liquid water structure by solutes has been proposed to be a key process in hydrate inhibition, but this hypothesis remains unproven. Here, we report the direct observation of the perturbation of the liquid water structure induced by amino acids using polarized Raman spectroscopy, and its influence on gas hydrate nucleation and growth kinetics. Amino acids with hydrophilic and/or electrically charged side chains disrupted the water structure and thus provided effective hydrate inhibition. The strong correlation between the extent of perturbation by amino acids and their inhibition performance constitutes convincing evidence for the perturbation inhibition mechanism. The present findings bring the practical applications of gas hydrates significantly closer, and provide a new perspective on the freezing and melting phenomena of naturally occurring gas hydrates.

  11. Gas hydrate inhibition by perturbation of liquid water structure.

    PubMed

    Sa, Jeong-Hoon; Kwak, Gye-Hoon; Han, Kunwoo; Ahn, Docheon; Lee, Kun-Hong

    2015-06-17

    Natural gas hydrates are icy crystalline materials that contain hydrocarbons, which are the primary energy source for this civilization. The abundance of naturally occurring gas hydrates leads to a growing interest in exploitation. Despite their potential as energy resources and in industrial applications, there is insufficient understanding of hydrate kinetics, which hinders the utilization of these invaluable resources. Perturbation of liquid water structure by solutes has been proposed to be a key process in hydrate inhibition, but this hypothesis remains unproven. Here, we report the direct observation of the perturbation of the liquid water structure induced by amino acids using polarized Raman spectroscopy, and its influence on gas hydrate nucleation and growth kinetics. Amino acids with hydrophilic and/or electrically charged side chains disrupted the water structure and thus provided effective hydrate inhibition. The strong correlation between the extent of perturbation by amino acids and their inhibition performance constitutes convincing evidence for the perturbation inhibition mechanism. The present findings bring the practical applications of gas hydrates significantly closer, and provide a new perspective on the freezing and melting phenomena of naturally occurring gas hydrates.

  12. Storage tank with liquid insulator for storing cryogenic fluids using water displacement

    SciTech Connect

    McCabe, J.S.; Stafford, D.C.; Laverman, R.J.

    1980-06-24

    For storing cryogenic liquids such as LNG at or slightly above atmospheric pressure, this design uses a tank with insulated vertical walls and an insulated top located in and surrounded by a body of water in communication with a layer of water inside the tank; the level of the tank contents can thus be controlled using the water-displacement principle. A layer of insulating liquid having a specific gravity lower than water and higher than LNG (or the cryogenic liquid being stored) separates the water and LNG while remaining liquid at the cryogenic temperature; the insulating liquid - pentanes, particularly isopentane, are suitable - must be essentially immiscible with water, LNG, or both. For preventing turbulent mixing of the water and LNG while the tank is being filled or emptied, a float in the form of a closed or open shell made partially or entirely of insulating material extends over the water layer and contains the insulating liquid.

  13. Nature of proton transport in a water-filled carbon nanotube and in liquid water.

    PubMed

    Chen, Ji; Li, Xin-Zheng; Zhang, Qianfan; Michaelides, Angelos; Wang, Enge

    2013-05-07

    Proton transport (PT) in bulk liquid water and within a thin water-filled carbon nanotube has been examined using ab initio path-integral molecular dynamics (PIMD). Barrierless proton transfer is observed in each case when quantum nuclear effects (QNEs) are accounted for. The key difference between the two systems is that in the nanotube facile PT is facilitated by a favorable pre-alignment of water molecules, whereas in bulk liquid water solvent reorganization is required prior to PT. Configurations where the quantum excess proton is delocalized over several adjacent water molecules along with continuous interconversion between different hydration states reveals that, as in liquid water, the hydrated proton under confinement is best described as a fluxional defect, rather than any individual idealized hydration state such as Zundel, Eigen, or the so-called linear H7O3(+) complex along the water chain. These findings highlight the importance of QNEs in intermediate strength hydrogen bonds (HBs) and explain why H(+) diffusion through nanochannels is impeded much less than other cations.

  14. Cloud and rain liquid water statistics in the CHUVA campaign

    NASA Astrophysics Data System (ADS)

    Calheiros, Alan J. P.; Machado, Luiz A. T.

    2014-07-01

    The purpose of this study is to present statistics related to the integration of cloud and rain liquid water and the profiles for different cloud types and regimes. From 2010 to 2012, the CHUVA project collected information regarding cloud and rain characteristics in different precipitation regimes in Brazil. CHUVA had four field campaigns between 2010 and 2011, located in the North, Northeast and Southeast regions of Brazil, covering the semi-arid, Amazon, coastal and mountain regions. The synergy of several instruments allowed us to classify rain events and describe the cloud processes regionally. Microwave radiometers, LiDAR, radar, and disdrometers were employed in this study. The rain type classification was made using vertical profiles of reflectivity (VPR) and polarimetric variables from dual polarization radar (XPOL). The integrated liquid water (ILWC) for non-precipitating clouds was retrieved with a microwave ground-based radiometer using a neural network. For rainy conditions, the profiles from the rain liquid water content (LWCR) and their integrated (ILWR) properties were estimated by Micro Rain Radar (MRR) and XPOL VPRs. For non-precipitating clouds, the ILWC values were larger for the sites in tropical regions, in particular near the coast, than for Southeast Brazil. For rainy cases, distinct LWCR profiles were observed for different rain classifications and regions. The differences are small for low rain rates and a distinction between different rainfall regimes is more evident for high rain rates. Vale and Belém clouds present the deepest layers and largest convective rain rates. The clouds in the Southeast region of Brazil (Vale do Paraíba) and North region (Belém) showed the largest reflectivity in the mixed and glaciated layers, respectively. In contrast, the Northeast coastal site (e.g. Fortaleza) showed larger values in the warm part of the clouds. Several analyses are presented, describing the cloud processes and the differences among the

  15. Identification of dimethoate-containing water using partitioned dispersive liquid-liquid microextraction coupled with near-infrared spectroscopy.

    PubMed

    Zhang, Ming; Geng, Ying; Xiang, Bingren

    2011-01-01

    A simple, rapid and efficient extraction procedure, partitioned dispersive liquid-liquid microextraction, has been developed in combination with near-infrared spectroscopy for the extraction and discrimination of dimethoate from aqueous samples. For this technique, the appropriate mixture of extraction solvent (CCl(4)) and disperser solvent (THF) was utilized. Partial least squares discriminant analysis was applied to build the model with several pre-process methods over the wavenumber regions between 7100 cm(-1) to 7300 cm(-1). The best model gave satisfactory classification accuracy, 98.6% for calibration set (n=74) and 97.6% for prediction set (n=42), using preprocessing of standard normal variate followed by Savitzky-Golay first derivative. The method was successfully applied to bottled water, tap water, lake water and farm water samples. The results demonstrated the possibility of near-infrared spectroscopy after partitioned dispersive liquid-liquid microextraction for the identification of water contaminated by dimethoate.

  16. The Boson peak in confined water: An experimental investigation of the liquid-liquid phase transition hypothesis

    NASA Astrophysics Data System (ADS)

    Mallamace, Francesco; Corsaro, Carmelo; Mallamace, Domenico; Wang, Zhe; Chen, Sow-Hsin

    2015-10-01

    The Boson peak (BP) of deeply cooled confined water is studied by using inelastic neutron scattering (INS) in a large interval of the ( P, T) phase plane. By taking into account the different behavior of such a collective vibrational mode in both strong and fragile glasses as well as in glass-forming materials, we were able to determine the Widom line that characterizes supercooled bulk water within the frame of the liquid-liquid phase transition (LLPT) hypothesis. The peak frequency and width of the BP correlated with the water polymorphism of the LLPT scenario, allowing us to distinguish the "low-density liquid" (LDL) and "high-density liquid" (HDL) phases in deeply cooled bulk water.Moreover, the BP properties afford a further confirmation of theWidom line temperature T W as the ( P, T) locus in which the local structure of water transforms from a predominately LDL form to a predominately HDL form.

  17. Transformation of DON in reclaimed water under solar light irradiation leads to decreased haloacetamide formation potential during chloramination.

    PubMed

    Du, Ye; Zhang, Xue; Li, Chao; Wu, Qian-Yuan; Huang, Huang; Hu, Hong-Ying

    2017-10-15

    Reclaimed water is usually stored in rivers or lakes before subsequent use. In storage ecosystems, the natural process of solar light irradiation plays a key role in water quality, altering disinfection byproduct formation potential in later use. This study investigated changes in haloacetamide formation potential (HAcAm FP) during subsequent chloramination when reclaimed water was exposed to solar light irradiation. Significant decreases in HAcAm FP were observed for the solar light irradiated reclaimed water, with reductions of 27%-69% for different haloacetamides. Moreover, transformation of dissolved organic nitrogen (DON) to inorganic nitrogen occurred during irradiation. The application of (15)N- labeled monochloramine indicated that the nitrogen source of the decreased HAcAms mainly originated from DON, rather than chloramine. Chloramination of the model compound l-asparagine after irradiation demonstrated that the decreased HAcAms could be attributed to the decrease in DON. After solar light irradiation, the brominated HAcAm FP in the presence of bromide was also reduced, while the bromine incorporation factor remained steady. Overall, this study revealed the contribution of natural processes in controlling HAcAm FP during subsequent chloramination, suggesting solar light irradiation is important to water purification during reclaimed water storage. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Radar and the Detection of Liquid Water on Mars

    NASA Technical Reports Server (NTRS)

    Roth, L. E.; Saunders, R. S.

    1985-01-01

    Detection of the seasonally variable radar reflectivity in the Goldstone Mars data (the Solis Lacus radar anomaly and the proposed interpretation in terms of the near-surface presence of liquid water created a controversy in the planetary science community. Over the past year, skepticism was voiced about the reality of the phenomenon of a seasonally variable radar reflectivity anywhere on Mars. The necessary background information and the pertinent data are reviewed in a format perhaps more convincing than that employed in the original presentation of the discovery. A summary of the results and recommendations for future work are included.

  19. The structural origin of anomalous properties of liquid water

    PubMed Central

    Nilsson, Anders; Pettersson, Lars G. M.

    2015-01-01

    Water is unique in its number of unusual, often called anomalous, properties. When hot it is a normal simple liquid; however, close to ambient temperatures properties, such as the compressibility, begin to deviate and do so increasingly on further cooling. Clearly, these emerging properties are connected to its ability to form up to four well-defined hydrogen bonds allowing for different local structural arrangements. A wealth of new data from various experiments and simulations has recently become available. When taken together they point to a heterogeneous picture with fluctuations between two classes of local structural environments developing on temperature-dependent length scales. PMID:26643439

  20. Solute-induced dissolution of hydrophobic ionic liquids in water.

    PubMed

    Rickert, Paul G; Stepinski, Dominique C; Rausch, David J; Bergeron, Ruth M; Jakab, Sandrine; Dietz, Mark L

    2007-04-15

    Significant solubilization of ostensibly water-immiscible ionic liquids (ILs) in acidic aqueous phases is induced by the presence of any of a variety of neutral extractants, the apparent result of the formation of the protonated form of the extractant and its subsequent exchange for the cationic component of the IL. The extent of this solubilization is shown to diminish with increasing hydrophobicity of the IL cation and decreasing extractant basicity. These observations raise concerns as to the viability of ILs as "drop in replacements" for traditional organic solvents in the solvent extraction of metal ions.

  1. Radar and the Detection of Liquid Water on Mars

    NASA Technical Reports Server (NTRS)

    Roth, L. E.; Saunders, R. S.

    1985-01-01

    Detection of the seasonally variable radar reflectivity in the Goldstone Mars data (the Solis Lacus radar anomaly and the proposed interpretation in terms of the near-surface presence of liquid water created a controversy in the planetary science community. Over the past year, skepticism was voiced about the reality of the phenomenon of a seasonally variable radar reflectivity anywhere on Mars. The necessary background information and the pertinent data are reviewed in a format perhaps more convincing than that employed in the original presentation of the discovery. A summary of the results and recommendations for future work are included.

  2. Water-based scintillators for large-scale liquid calorimetry

    SciTech Connect

    Winn, D.R.; Raftery, D.

    1985-02-01

    We have investigated primary and secondary solvent intermediates in search of a recipe to create a bulk liquid scintillator with water as the bulk solvent and common fluors as the solutes. As we are not concerned with energy resolution below 1 MeV in large-scale experiments, light-output at the 10% level of high-quality organic solvent based scintillators is acceptable. We have found encouraging performance from industrial surfactants as primary solvents for PPO and POPOP. This technique may allow economical and environmentally safe bulk scintillator for kiloton-sized high energy calorimetry.

  3. Investigation of a liquid-fed water resistojet plume

    NASA Technical Reports Server (NTRS)

    Manzella, D. H.; Carney, L. M.

    1989-01-01

    Measurements of mass flux and flow angle were taken throughout the forward flow region of the exhaust of a liquid-fed water resistojet using a quartz crystal microbalance (QCM). The resistojet operated at a mass flow rate of 0.1 g/s with a power input of 330 Watts. Measured values were compared to theoretical predictions obtained by employing a source flow approximation. Excellent agreement between predicted and measured mass flux values was attained; however, this agreement was highly dependent on knowledge of nozzle flow conditions. Measurements of the temperature at which the exhaust condensed on the QCM were obtained as a function of incident mass flux.

  4. Improvement of coal water slurry property through coal physicochemical modifications by microwave irradiation and thermal heat

    SciTech Connect

    Jun Cheng; Junhu Zhou; Yanchang Li; Jianzhong Liu; Kefa Cen

    2008-07-15

    To improve the coal water slurry (CWS) property made from Chinese Shenhua coal with high inherent moisture and oxygen contents, microwave irradiation and thermal heat were employed to modify the coal physicochemical property. Microwave irradiation reduces the inherent moisture and reforms the oxygenic function groups, while it decreases the total specific surface area. Thermal heat markedly decreases the inherent moisture, volatile, and oxygen contents, while it dramatically increases the total specific surface area. Therefore, microwave irradiation gives a higher CWS concentration and a better rheological behavior than thermal heat, while it remarkably reduces the operation time and energy consumption. The maximum CWS concentration given by microwave irradiation at 420 W for 60 s is 62.14%, which is not only higher than that of 60.41% given by thermal heat at 450{sup o}C for 0.5 h but also higher than the initial 58.23%. Meanwhile, the minimum shear stress given by microwave irradiation is 36.4 Pa at the shear rate of 100 s{sup -1}, which is not only lower than that of 42.4 Pa given by thermal heat but also lower than the initial 79.8 Pa. The minimum unit energy consumption of 0.115 kWh/(kg of coal) and electricity cost of 4.6 U.S. $/(ton of coal) for CWS concentration promotion by 1% are obtained at 420 W for 20 s in the microwave oven. The unit energy consumptions for CWS concentration promotion and inherent moisture removal by thermal heat are, respectively, 214 and 22.5 times higher than those by microwave irradiation, while the energy use efficiencies are on the converse. 27 refs., 11 figs., 2 tabs.

  5. Nondestructive verification with minimal movement of irradiated light-water-reactor fuel assemblies

    SciTech Connect

    Phillips, J.R.; Bosler, G.E.; Halbig, J.K.; Klosterbuer, S.F.; Menlove, H.O.

    1982-10-01

    Nondestructive verification of irradiated light-water reactor fuel assemblies can be performed rapidly and precisely by measuring their gross gamma-ray and neutron signatures. A portable system measured fuel assemblies with exposures ranging from 18.4 to 40.6 GWd/tU and with cooling times ranging from 1575 to 2638 days. Differences in the measured results for side or corner measurements are discussed. 25 figures, 20 tables.

  6. The Convenient Synthesis of Unsaturated Nucleoside Analogues in Water under Microwave Irradiation.

    PubMed

    Xia, Ran; Sun, Li-Ping

    2016-01-01

    A convenient method for the regioselective synthesis of unsaturated nucleoside analogs in water under microwave irradiation was developed. All pyrimidine and purine nucleoside derivatives were exclusively alkylated at N1 and N9 respectively in good to excellent yields. In addition, this system could tolerate a broad range of functional groups, such as chloro, bromo, iodo, alkyl, amino, and hydroxyl groups. More importantly, the reaction scale could be enlarged to 50 mmol which made this route attractive for industrial application.

  7. Interplay of the Glass Transition and the Liquid-Liquid Phase Transition in Water

    PubMed Central

    Giovambattista, Nicolas; Loerting, Thomas; Lukanov, Boris R.; Starr, Francis W.

    2012-01-01

    Water has multiple glassy states, often called amorphous ices. Low-density (LDA) and high-density (HDA) amorphous ice are separated by a dramatic, first-order like phase transition. It has been argued that the LDA-HDA transformation connects to a first-order liquid-liquid phase transition (LLPT) above the glass transition temperature Tg. Direct experimental evidence of the LLPT is challenging to obtain, since the LLPT occurs at conditions where water rapidly crystallizes. In this work, we explore the implications of a LLPT on the pressure dependence of Tg(P) for LDA and HDA by performing computer simulations of two water models – one with a LLPT, and one without. In the absence of a LLPT, Tg(P) for all glasses nearly coincide. When there is a LLPT, different glasses exhibit dramatically different Tg(P) which are directly linked with the LLPT. Available experimental data for Tg(P) are only consistent with the scenario including a LLPT. PMID:22550566

  8. Gamma irradiation-induced Cd 2+ and Pb 2+ removal from different kinds of water

    NASA Astrophysics Data System (ADS)

    Guo, Zhaobing; Tang, Dengyong; Liu, Xiaguo; Zheng, Zheng

    2008-09-01

    Gamma irradiation-induced removal of cadmium ion (Cd 2+) and lead ion (Pb 2+) in different kinds of water was investigated. It is observed that solution pH, dissolved oxygen (DO) concentration, sodium carbonate and EDTA played an important effect on Cd 2+ and Pb 2+ removal. Low solution pH, low DO concentration and sodium carbonate were favorable for removal of Cd 2+ and Pb 2+ by reducing species, while the presence of EDTA in solution restrained Cd 2+ and Pb 2+ reduction. Pb 2+ removal percentage was higher compared to that of Cd 2+ at the same experimental conditions. Cd 2+ and Pb 2+ removal under different conditions was well described by the pseudo-first-order kinetics model. Cd 2+ and Pb 2+ removal in different water followed an increasing order: water inflowwaterwater. In addition, gamma irradiation resulted in a slight decrease in pH and TOC values of water inflow of municipal sewage treatment plant.

  9. LIPSIE device: Pb-17Li irradiation in water loop with on-line tritium measurements

    NASA Astrophysics Data System (ADS)

    Thevenot, G.; Lefevre, F.; Estrade, J.; Roche, M.; Flament, T.; Terlain, A.

    1992-09-01

    Due to the low solubility and high diffusivity of tritium in Pb-17Li, tritium permeation through the walls of a water-cooled Pb-17Li blanket has to be investigated. This has been done in Lipsie irradiation performed by CEA in the OSIRIS reactor. The Isabelle 4 PWR loop, in the OSIRIS reactor pool, has been adapted to allow us to irradiate in demineralized water at 15 MPa and 300°C a 316L stainless steel capsule of 0.025 m diameter, containing about 0, 450 kg of Pb-17Li manufactured with natural lithium. Two tritium measurements systems have been specially developed around radioactivity scintillation counting devices: one for tritium in cooling water out of the capsule and one for tritium in helium gas after sweeping or sparging in Pb-17Li inside the capsule. This paper describes the loop used for this irradiation and the tritium measurement systems. The experiment will enable us to estimate tritium permeation rate through the capsule wall in Demo-representative conditions of tritium in Pb-17Li and also study the effect of oxidation of the external capsule wall on tritium permeation by oxygen injection near the capsule.

  10. Photolytic dehalogenation of disinfection byproducts in water by natural sunlight irradiation.

    PubMed

    Abusallout, Ibrahim; Hua, Guanghui

    2016-09-01

    The aqueous photolysis of halogenated disinfection byproducts (DBPs) by natural sunlight irradiation was studied to determine their photolytic dehalogenation kinetics. Total organic halogen analysis was used to quantify the dehalogenation extents of DBPs during outdoor photolysis experiments. Dichloroacetamide, chloral hydrate, chloroform, dichloroacetonitrile, monochloro-, monobromo-, dichloro-, dibromo-, and trichloroacetic acids were generally resistant to photolytic dehalogenation and showed less than 10% reduction after 6 h sunlight irradiation. Monoiodoacetic acid, tribromoacetic acid, bromoform, dibromoacetonitrile, and trichloronitromethane showed moderate to high dehalogenation degrees with half-lives of 4.0-19.3 h. Diiodoacetic acid, triiodoacetic acid, and iodoform degraded rapidly under the sunlight irradiation and exhibited half-lives of 5.3-10.2 min. In general, the photosensitive cleavage of carbon-halogen bonds of DBPs increased with increasing number of halogens (tri- > di- > mono-halogenated) and size of the substituted halogens (I > Br > Cl). Nitrate, nitrite, and pH had little impact on the photodehalogenation of DBPs under typical levels in surface waters. The presence of natural organic matter (NOM) inhibited the photodehalogenation of DBPs by light screening. The NOM inhibiting effects were more pronounced for the fast degrading iodinated DBPs. The results of this study improve our understanding about the photolytic dehalogenation of wastewater-derived DBPs in surface waters during water reuse.

  11. Determination of organic compounds in water using dispersive liquid-liquid microextraction.

    PubMed

    Rezaee, Mohammad; Assadi, Yaghoub; Milani Hosseini, Mohammad-Reza; Aghaee, Elham; Ahmadi, Fardin; Berijani, Sana

    2006-05-26

    A new microextraction technique termed dispersive liquid-liquid microextraction (DLLME) was developed. DLLME is a very simple and rapid method for extraction and preconcentration of organic compounds from water samples. In this method, the appropriate mixture of extraction solvent (8.0 microL C2Cl4) and disperser solvent (1.00 mL acetone) are injected into the aqueous sample (5.00 mL) by syringe, rapidly. Therefore, cloudy solution is formed. In fact, it is consisted of fine particles of extraction solvent which is dispersed entirely into aqueous phase. After centrifuging, the fine particles of extraction solvent are sedimented in the bottom of the conical test tube (5.0 +/- 0.2 microL). The performance of DLLME is illustrated with the determination of polycyclic aromatic hydrocarbons (PAHs) in water samples by using gas chromatography-flame ionization detection (GC-FID). Some important parameters, such as kind of extraction and disperser solvent and volume of them, and extraction time were investigated. Under the optimum conditions the enrichment factor ranged from 603 to 1113 and the recovery ranged from 60.3 to 111.3%. The linear range was 0.02-200 microg/L (four orders of magnitude) and limit of detection was 0.007-0.030 microg/L for most of analytes. The relative standard deviations (RSDs) for 2 microg/L of PAHs in water by using internal standard were in the range 1.4-10.2% (n = 5). The recoveries of PAHs from surface water at spiking level of 5.0 microg/L were 82.0-111.0%. The ability of DLLME technique in the extraction of other organic compounds such as organochlorine pesticides, organophosphorus pesticides and substituted benzene compounds (benzene, toluene, ethyl benzene, and xylenes) from water samples were studied. The advantages of DLLME method are simplicity of operation, rapidity, low cost, high recovery, and enrichment factor.

  12. On the implications of aerosol liquid water and phase separation for organic aerosol mass

    EPA Science Inventory

    Organic compounds and liquid water are major aerosol constituents in the southeast United States (SE US). Water associated with inorganic constituents (inorganic water) can contribute to the partitioning medium for organic aerosol when relative humidities or organic matter to org...

  13. On the implications of aerosol liquid water and phase separation for organic aerosol mass

    EPA Science Inventory

    Organic compounds and liquid water are major aerosol constituents in the southeast United States (SE US). Water associated with inorganic constituents (inorganic water) can contribute to the partitioning medium for organic aerosol when relative humidities or organic matter to org...

  14. Gas and liquid measurements in air-water bubbly flows

    SciTech Connect

    Zhou, X.; Doup, B.; Sun, X.

    2012-07-01

    Local measurements of gas- and liquid-phase flow parameters are conducted in an air-water two-phase flow loop. The test section is a vertical pipe with an inner diameter of 50 mm and a height of 3.2 m. The measurements are performed at z/D = 10. The gas-phase measurements are performed using a four-sensor conductivity probe. The data taken from this probe are processed using a signal processing program to yield radial profiles of the void fraction, bubble velocity, and interfacial area concentration. The velocity measurements of the liquid-phase are performed using a state-of-the-art Particle Image Velocimetry (PIV) system. The raw PIV images are acquired using fluorescent particles and an optical filtration device. Image processing is used to remove noise in the raw PIV images. The statistical cross correlation is introduced to determine the axial velocity field and turbulence intensity of the liquid-phase. Measurements are currently being performed at z/D = 32 to provide a more complete data set. These data can be used for computational fluid dynamic model development and validation. (authors)

  15. Comparison of dispersion behavior of agglomerated particles in liquid between ultrasonic irradiation and mechanical stirring.

    PubMed

    Sumitomo, Syunsuke; Koizumi, Hayato; Uddin, Md Azhar; Kato, Yoshiei

    2018-01-01

    The particle dispersion behavior was compared for ultrasonic irradiation and mechanical stirring. The experiment and calculation were carried out with polymethylmethacrylate (PMMA) particles. The dispersion rate of the agglomerated particles increased with the decreasing ultrasonic frequency and the increasing electric power, whereas it increased with the increasing rotation speed for the mechanical stirring. The temporal change in the particle dispersion proceeded stably after passage of a long time. The dispersion of the ultrasonic irradiation was suggested to occur by the erosion from the surface of the cluster one by one due to the bulk cavitation as well as the division into smaller particles because of the inner cavitation, and that of the mechanical stirring mainly by the division into smaller clusters due to the shear stress flow. Based on the experimental results, mathematical models for the ultrasonic irradiation and mechanical stirring were developed with the dispersion and agglomeration terms and the calculation of the temporal change in the total cluster number at the different operational factors agreed with the experiments. The dispersion efficiency of the ultrasonic irradiation was larger than that of the mechanical stirring at the lower input power, but it was reversed at the higher input power. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Innovative Strategy on Hydrogen Evolution Reaction Utilizing Activated Liquid Water

    NASA Astrophysics Data System (ADS)

    Hwang, Bing-Joe; Chen, Hsiao-Chien; Mai, Fu-Der; Tsai, Hui-Yen; Yang, Chih-Ping; Rick, John; Liu, Yu-Chuan

    2015-11-01

    Splitting water for hydrogen production using light, or electrical energy, is the most developed ‘green technique’. For increasing efficiency in hydrogen production, currently, the most exciting and thriving strategies are focused on efficient and inexpensive catalysts. Here, we report an innovative idea for efficient hydrogen evolution reaction (HER) utilizing plasmon-activated liquid water with reduced hydrogen-bonded structure by hot electron transfer. This strategy is effective for all HERs in acidic, basic and neutral systems, photocatalytic system with a g-C3N4 (graphite carbon nitride) electrode, as well as in an inert system with an ITO (indium tin oxide) electrode. Compared to deionized water, the efficiency of HER increases by 48% based on activated water ex situ on a Pt electrode. Increase in energy efficiency from activated water is 18% at a specific current yield of -20 mA in situ on a nanoscale-granulated Au electrode. Moreover, the onset potential of -0.023 V vs RHE was very close to the thermodynamic potential of the HER (0 V). The measured current density at the corresponding overpotential for HER in an acidic system was higher than any data previously reported in the literature. This approach establishes a new vista in clean green energy production.

  17. Innovative Strategy on Hydrogen Evolution Reaction Utilizing Activated Liquid Water

    PubMed Central

    Hwang, Bing-Joe; Chen, Hsiao-Chien; Mai, Fu-Der; Tsai, Hui-Yen; Yang, Chih-Ping; Rick, John; Liu, Yu-Chuan

    2015-01-01

    Splitting water for hydrogen production using light, or electrical energy, is the most developed ‘green technique’. For increasing efficiency in hydrogen production, currently, the most exciting and thriving strategies are focused on efficient and inexpensive catalysts. Here, we report an innovative idea for efficient hydrogen evolution reaction (HER) utilizing plasmon-activated liquid water with reduced hydrogen-bonded structure by hot electron transfer. This strategy is effective for all HERs in acidic, basic and neutral systems, photocatalytic system with a g-C3N4 (graphite carbon nitride) electrode, as well as in an inert system with an ITO (indium tin oxide) electrode. Compared to deionized water, the efficiency of HER increases by 48% based on activated water ex situ on a Pt electrode. Increase in energy efficiency from activated water is 18% at a specific current yield of −20 mA in situ on a nanoscale-granulated Au electrode. Moreover, the onset potential of −0.023 V vs RHE was very close to the thermodynamic potential of the HER (0 V). The measured current density at the corresponding overpotential for HER in an acidic system was higher than any data previously reported in the literature. This approach establishes a new vista in clean green energy production. PMID:26541371

  18. The role of UV-irradiation pretreatment on the degradation of 2,4-dichlorophenoxyacetic acid in water.

    PubMed

    Tchaikovskaya, O; Sokolova, I; Mayer, G V; Karetnikova, E; Lipatnikova, E; Kuzmina, S; Volostnov, D

    2011-01-01

    The degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) in water by the combination process of UV-irradiation, humic acids and activated sludge treatment has been studied. The photoreaction rate of all irradiated samples was lowest for the sample irradiated at 308 nm (the XeCl excilamp) in the absence and in the presence of humic acids, and highest for the sample irradiated at 222 nm (the KrCl excilamp). Photolysis of 2,4-D has been shown to enhance the subsequent microbial degradation. Copyright © 2010 John Wiley & Sons, Ltd.

  19. Distribution of binding energies of a water molecule in the water liquid-vapor interface

    SciTech Connect

    Chempath, Shaji; Pratt, Lawrence R

    2008-01-01

    Distributions of binding energies of a water molecule in the water liquid-vapor interface are obtained on the basis of molecular simulation with the SPC/E model of water. These binding energies together with the observed interfacial density profile are used to test a minimally conditioned Gaussian quasi-chemical statistical thermodynamic theory. Binding energy distributions for water molecules in that interfacial region clearly exhibit a composite structure. A minimally conditioned Gaussian quasi-chemical model that is accurate for the free energy of bulk liquid water breaks down for water molecules in the liquid-vapor interfacial region. This breakdown is associated with the fact that this minimally conditioned Gaussian model would be inaccurate for the statistical thermodynamics of a dilute gas. Aggressive conditioning greatly improves the performance of that Gaussian quasi-chemical model. The analogy between the Gaussian quasi-chemical model and dielectric models of hydration free energies suggests that naive dielectric models without the conditioning features of quasi-chemical theory will be unreliable for these interfacial problems. Multi-Gaussian models that address the composite nature of the binding energy distributions observed in the interfacial region might provide a mechanism for correcting dielectric models for practical applications.

  20. ETV REPORT AND VERIFICATION STATEMENT; EVALUATION OF LOBO LIQUIDS RINSE WATER RECOVERY SYSTEM

    EPA Science Inventory

    The Lobo Liquids Rinse Water Recovery System (Lobo Liquids system) was tested, under actual production conditions, processing metal finishing wastewater, at Gull Industries in Houston, Texas. The verification test evaluated the ability of the ion exchange (IX) treatment system t...

  1. ETV REPORT AND VERIFICATION STATEMENT; EVALUATION OF LOBO LIQUIDS RINSE WATER RECOVERY SYSTEM

    EPA Science Inventory

    The Lobo Liquids Rinse Water Recovery System (Lobo Liquids system) was tested, under actual production conditions, processing metal finishing wastewater, at Gull Industries in Houston, Texas. The verification test evaluated the ability of the ion exchange (IX) treatment system t...

  2. Forecast model applications of retrieved three dimensional liquid water fields

    NASA Technical Reports Server (NTRS)

    Raymond, William H.; Olson, William S.

    1990-01-01

    Forecasts are made for tropical storm Emily using heating rates derived from the SSM/I physical retrievals described in chapters 2 and 3. Average values of the latent heating rates from the convective and stratiform cloud simulations, used in the physical retrieval, are obtained for individual 1.1 km thick vertical layers. Then, the layer-mean latent heating rates are regressed against the slant path-integrated liquid and ice precipitation water contents to determine the best fit two parameter regression coefficients for each layer. The regression formulae and retrieved precipitation water contents are utilized to infer the vertical distribution of heating rates for forecast model applications. In the forecast model, diabatic temperature contributions are calculated and used in a diabatic initialization, or in a diabatic initialization combined with a diabatic forcing procedure. Our forecasts show that the time needed to spin-up precipitation processes in tropical storm Emily is greatly accelerated through the application of the data.

  3. Hot electron dominated rapid transverse ionization growth in liquid water.

    PubMed

    Brown, Michael S; Erickson, Thomas; Frische, Kyle; Roquemore, William M

    2011-06-20

    Pump/probe optical-transmission measurements are used to monitor in space and time the ionization of a liquid column of water following impact of an 800-nm, 45-fs pump pulse. The pump pulse strikes the 53-μm-diameter column normal to its axis with intensities up to 2 × 10(15) W/cm2. After the initial photoinization and for probe delay times < 500 fs, the neutral water surrounding the beam is rapidly ionized in the transverse direction, presumably by hot electrons with initial velocities of 0.55 times the speed of light (relativistic kinetic energy of ~100 keV). Such velocities are unusual for condensed-matter excitation at the stated laser intensities.

  4. Release of liquid water from the Space Shuttle

    NASA Technical Reports Server (NTRS)

    Pike, C. P.; Knecht, D. J.; Viereck, R. A.; Murad, E.; Kofsky, I. L.; Bagian, J. P.; Buchli, J. F.

    1990-01-01

    Groundbased and onboard video images of a sunlit Shuttle Orbiter water dump are interpreted as showing that the continuous 1-mm-diameter liquid stream quickly breaks up in near-vacuum to form ice/snow particles of two characteristic sizes. Discrete large droplets are most evident in the close-in photographs, and unresolved submicron 'fog' from recondensation of overexpanded evaporated water appears to dominate the ground-telescope photographs of the 2.5 km long optically detectable trail. The mean diameter of the smaller particles was estimated from the spatial distribution of visible radiance using a model of their energy balance, (small) surface roughening as they sublime, and Mie scattering of pre-dawn sunlight. The results are consistent with those from recent space-tank simulations.

  5. In-line coupled single drop liquid-liquid-liquid microextraction with capillary electrophoresis for determining fluoroquinolones in water samples.

    PubMed

    Springer, Valeria H; Lista, Adriana G

    2015-07-01

    A simple in-line single drop liquid-liquid-liquid microextraction (SD-LLLME) coupled with CE for the determination of two fluoroquinolones was developed. The method is capable to quantify trace amount of analytes in water samples and to improve the sensitivity of CE detection. For the SD-LLLME, a thin layer of organic phase was used to separate a drop of 0.1 M NaOH hanging at the inlet of the capillary from the aqueous donor phase. By this way, the analytes were extracted to the acceptor phase through the organic layer based on their acidic/basic dissociation equilibrium. The drop was immersed into the organic phase during 10 min for extraction and then it is directly injected into the capillary for the analysis. Parameters such as type and volume of organic solvent phase, aqueous donor, and acceptor phases and extraction time and temperature were optimized. The enrichment factor was calculated, resulting 40-fold for enrofloxacin (ENR) and sixfold for ciprofloxacin (CIP). The linear range were 20-400 μg/L for ENR and 60-400 μg/L for CIP. The detection limits were 10.1 μg/L and 55.3 μg/L for ENR and CIP, respectively, and a good reproducibility was obtained (4.4% for ENR and 5.6% for CIP). Two real water samples were analysed applying the new method and the obtained results presented satisfactory recovery percentages (90-100.3%). © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Response functions near the liquid-liquid critical point of ST2 water

    NASA Astrophysics Data System (ADS)

    Lascaris, Erik; Kesselring, T. A.; Franzese, G.; Buldyrev, S. V.; Herrmann, H. J.; Stanley, H. E.

    2013-02-01

    We simulate the ST2 water model for time periods up to 1000 ns, and for four different system sizes, N = 63, 73, 83, and 93. We locate the liquid-liquid phase transition line and its critical point in the supercooled region. Near the liquidliquid phase transition line, we observe that the system continuously flips between the low-density and high-density liquid phases. We analyze the transition line further by calculating two thermodynamic response functions, the isobaric specific heat capacity CP and the isothermal compressibility KT. We use two different methods: (i) from fluctuations and (ii) with the relevant thermodynamic derivative. We find that, within the accuracy of our simulations, the maxima of two different response functions occur at the same temperatures. The lines of CP and KT maxima below the critical pressure approximate the Widom line which is continuous with the line of first-order transitions in the two-phase region where we observe the phase flipping.

  7. Rapid determination of octanol-water partition coefficient using vortex-assisted liquid-liquid microextraction.

    PubMed

    Román, Iván P; Mastromichali, Anna; Tyrovola, Konstantina; Canals, Antonio; Psillakis, Elefteria

    2014-02-21

    Vortex-assisted liquid-liquid microextraction (VALLME) coupled with high-performance liquid chromatography (HPLC) is proposed here for the rapid determination of octanol-water partitioning coefficients (Kow). VALLME uses vortex agitation, a mild emulsification procedure, to disperse microvolumes of octanol in the aqueous phase thus increasing the interfacial contact area and ensuring faster partitioning rates. With VALLME, 2min were enough to achieve equilibrium conditions between the octanolic and aqueous phases. Upon equilibration, separation was achieved using centrifugation and the octanolic microdrop was collected and analyzed in a HPLC system. Six model compounds with logKow values ranging between ∼0.5 and 3.5 were used during the present investigations. The proposed method produced logKow values that were consistent with previously published values and the recorded uncertainty was well within the acceptable log unit range. Overall, the key features of the proposed Kow determination procedure comprised speed, reliability, simplicity, low cost and minimal solvent consumption. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Discovery of luminescence of water during radiation irradiation and application for medical physics

    NASA Astrophysics Data System (ADS)

    Yamamoto, Seiichi

    2017-02-01

    Optical imaging detecting Cerenkov-light is a promising approach for molecular imaging or radiation therapy, but it was not yet conducted for proton therapy because light was not thought to be produced with the energy ranges because they are lower than Cerenkov-light threshold. Contrary to this consensus, our research group found that luminescence was emitted from water during proton-beam irradiation. The luminescence images of water phantoms showed clear Bragg peak, and the measured proton ranges from the images were almost the same as those obtained with an ionization chamber. The luminescence was also observed for carbon-ion and low energy X-ray photons.

  9. Thin Liquid Water Clouds: Their Importance and Our Challenge

    SciTech Connect

    Turner, David D.; Vogelmann, A. M.; Austin, Richard T.; Barnard, James C.; Cady-Pereira, Karen; Chiu, C.; Clough, Shepard A.; Flynn, Connor J.; Khaiyer, Mandana M.; Liljegren, James C.; Johnson, Karen L.; Lin, B.; Long, Charles N.; Marshak, A.; Matrosov, S. Y.; McFarlane, Sally A.; Miller, Mark A.; Min, Qilong; Minnis, Patrick; O'Hirok, William; Wang, Zhien; Wiscombe, Warren J.

    2007-02-19

    Many of the clouds important to the Earth’s energy balance, from the tropics to the Arctic, are optically thin and contain liquid water. Longwave and shortwave radiative fluxes are very sensitive to small perturbations of the cloud liquid water path (LWP) when the LWP is small (i.e., <100 gm-2) and, thus, the radiative properties of these clouds must be well understood to capture them correctly in climate models. Here we review the importance of these thin clouds to the Earth’s energy balance, and explain the difficulties in observing them. In particular, because these clouds are optically thin, potentially mixed-phase, and often broken (i.e., have large 3-D variability), it is challenging to retrieve their microphysical properties accurately. We describe a retrieval algorithm intercomparison that was conducted to evaluate the issues involved. Seventeen different algorithms participated and their retrieved LWP, optical depth, and effective radii are evaluated using data from several case studies. Surprisingly, evaluation of the simplest case, a single-layer overcast cloud, revealed that huge discrepancies exist among the various techniques, even among different algorithms that are in the same general classification. This suggests that, despite considerable advances that have occurred in the field, much more work must be done, and we discuss fruitful avenues for future research.

  10. Heavy ion irradiation of crystalline water ice. Cosmic ray amorphisation cross-section and sputtering yield

    NASA Astrophysics Data System (ADS)

    Dartois, E.; Augé, B.; Boduch, P.; Brunetto, R.; Chabot, M.; Domaracka, A.; Ding, J. J.; Kamalou, O.; Lv, X. Y.; Rothard, H.; da Silveira, E. F.; Thomas, J. C.

    2015-04-01

    Context. Under cosmic irradiation, the interstellar water ice mantles evolve towards a compact amorphous state. Crystalline ice amorphisation was previously monitored mainly in the keV to hundreds of keV ion energies. Aims: We experimentally investigate heavy ion irradiation amorphisation of crystalline ice, at high energies closer to true cosmic rays, and explore the water-ice sputtering yield. Methods: We irradiated thin crystalline ice films with MeV to GeV swift ion beams, produced at the GANIL accelerator. The ice infrared spectral evolution as a function of fluence is monitored with in-situ infrared spectroscopy (induced amorphisation of the initial crystalline state into a compact amorphous phase). Results: The crystalline ice amorphisation cross-section is measured in the high electronic stopping-power range for different temperatures. At large fluence, the ice sputtering is measured on the infrared spectra, and the fitted sputtering-yield dependence, combined with previous measurements, is quadratic over three decades of electronic stopping power. Conclusions: The final state of cosmic ray irradiation for porous amorphous and crystalline ice, as monitored by infrared spectroscopy, is the same, but with a large difference in cross-section, hence in time scale in an astrophysical context. The cosmic ray water-ice sputtering rates compete with the UV photodesorption yields reported in the literature. The prevalence of direct cosmic ray sputtering over cosmic-ray induced photons photodesorption may be particularly true for ices strongly bonded to the ice mantles surfaces, such as hydrogen-bonded ice structures or more generally the so-called polar ices. Experiments performed at the Grand Accélérateur National d'Ions Lourds (GANIL) Caen, France. Part of this work has been financed by the French INSU-CNRS programme "Physique et Chimie du Milieu Interstellaire" (PCMI) and the ANR IGLIAS.

  11. Ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction followed high-performance liquid chromatography for the determination of ultraviolet filters in environmental water samples.

    PubMed

    Zhang, Yufeng; Lee, Hian Kee

    2012-10-31

    In the present study, a rapid, highly efficient and environmentally friendly sample preparation method named ionic liquid-based ultrasound-assisted dispersive liquid-liquid microextraction (IL-USA-DLLME), followed by high performance liquid chromatography (HPLC) has been developed for the extraction and preconcentration of four benzophenone-type ultraviolet (UV) filters (viz. benzophenone (BP), 2-hydroxy-4-methoxybenzophenone (BP-3), ethylhexyl salicylate (EHS) and homosalate (HMS)) from three different water matrices. The procedure was based on a ternary solvent system containing tiny droplets of ionic liquid (IL) in the sample solution formed by dissolving an appropriate amount of the IL extraction solvent 1-hexyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate ([HMIM][FAP]) in a small amount of water-miscible dispersive solvent (methanol). An ultrasound-assisted process was applied to accelerate the formation of the fine cloudy solution, which markedly increased the extraction efficiency and reduced the equilibrium time. Various parameters that affected the extraction efficiency (such as type and volume of extraction and dispersive solvents, ionic strength, pH and extraction time) were evaluated. Under optimal conditions, the proposed method provided good enrichment factors in the range of 354-464, and good repeatability of the extractions (RSDs below 6.3%, n=5). The limits of detection were in the range of 0.2-5.0 ng mL(-1), depending on the analytes. The linearities were between 1 and 500 ng mL(-1) for BP, 5 and 500 ng mL(-1) for BP-3 and HMS and 10 and 500 ng mL(-1) for EHS. Finally, the proposed method was successfully applied to the determination of UV filters in river, swimming pool and tap water samples and acceptable relative recoveries over the range of 71.0-118.0% were obtained.

  12. IR spectra of water droplets in no man's land and the location of the liquid-liquid critical point

    NASA Astrophysics Data System (ADS)

    Ni, Yicun; Skinner, J. L.

    2016-09-01

    No man's land is the region in the metastable phase diagram of water where it is very difficult to do experiments on liquid water because of homogeneous nucleation to the crystal. There are a number of estimates of the location in no man's land of the liquid-liquid critical point, if it exists. We suggest that published IR absorption experiments on water droplets in no man's land can provide information about the correct location. To this end, we calculate theoretical IR spectra for liquid water over a wide range of temperatures and pressures, using our E3B3 model, and use the results to argue that the temperature dependence of the experimental spectra is inconsistent with several of the estimated critical point locations, but consistent with others.

  13. IR spectra of water droplets in no man's land and the location of the liquid-liquid critical point.

    PubMed

    Ni, Yicun; Skinner, J L

    2016-09-28

    No man's land is the region in the metastable phase diagram of water where it is very difficult to do experiments on liquid water because of homogeneous nucleation to the crystal. There are a number of estimates of the location in no man's land of the liquid-liquid critical point, if it exists. We suggest that published IR absorption experiments on water droplets in no man's land can provide information about the correct location. To this end, we calculate theoretical IR spectra for liquid water over a wide range of temperatures and pressures, using our E3B3 model, and use the results to argue that the temperature dependence of the experimental spectra is inconsistent with several of the estimated critical point locations, but consistent with others.

  14. Quantitation of antioxidants in water samples using ionic liquid dispersive liquid-liquid microextraction followed by high-performance liquid chromatography-ultraviolet detection.

    PubMed

    Sobhi, Hamid Reza; Kashtiaray, Amir; Farahani, Hadi; Farahani, Mohammad Reza

    2011-01-01

    A simple and efficient method, ionic liquid-based dispersive liquid-liquid microextraction combined with high-performance liquid chromatography-ultraviolet detection (HPLC-UV), has been applied for the extraction and determination of some antioxidants (Irganox 1010, Irganox 1076 and Irgafos 168) in water samples. The microextraction efficiency factors were investigated and optimized: 1-hexyl-3-methylimidazolium hexafluorophosphate [C(6)MIM][PF(6)] (0.06 g) as extracting solvent, methanol (0.5 mL) as disperser solvent without salt addition. Under the selected conditions, enrichment factors up to 48-fold, limits of detection (LODs) of 5.0-10.0 ng/mL and dynamic linear ranges of 25-1500 ng/mL were obtained. A reasonable repeatability (RSD≤11.8%, n=5) with satisfactory linearity (r(2)≥0.9954) of the results illustrated a good performance of the presented method. The accuracy of the method was tested by the relative recovery experiments on spiked samples, with results ranging from 85 to 118%. Finally, the method was successfully applied for determination of the analytes in several real water samples.

  15. Effect of gamma irradiation and water activity on mycotoxin production of Alternaria in tomato paste and juice.

    PubMed

    Aziz, N H; Farag, S; Hassanin, M A

    1991-01-01

    Gamma-irradiation, water activity (aw) and incubation temperature were found to affect the production of tenuazonic acid (TZA) by Alternaria alternata in tomato paste and juice. By increasing the irradiation doses, the dry weight as well as TZA decreased greatly until complete inhibition at 4 kGy. Greatest production of TZA occurred at 0.98 aw (57.5 micrograms/g and 26.3 micrograms/g) for both tomato paste and juice, respectively, at 25 degrees C. Changing temperature and aw altered the relative amounts of TZA produced in tomato paste und juice by unirradiated and irradiated conidia of A. alternata. Only trace amount of TZA was detected at 0.98 aw (1.50 micrograms/g) by 3 kGy-irradiated conidia in tomato paste, while it was inhibited completely in juice. Increasing gamma-irradiation doses and decreasing water activities decreased greatly or inhibited TZA production in both tomato paste and juice.

  16. New metal-organic nanomaterials synthesized by laser irradiation of organic liquids

    SciTech Connect

    Kuzmin, Stanislav L.; Wesolowski, Michal J.; Duley, Walter W.

    2014-03-31

    A new type of metal-organic composition consisting of clusters of nanoparticles has been synthesised by laser irradiation of metallocene/benzene solutions. The metallocene molecules in this reaction become the source of the metal. Exposure to high-energy femtosecond laser pulses dehydrogenate benzene molecules and initiate the high-temperature high-pressure conditions that results in the synthesis of new materials. Irradiation experiments have been carried out on ferrocene/benzene and on other solutions. With ferrocene the synthesis of a new compound has been confirmed by X-ray powder diffraction as the peaks detected do not correspond to any known substance in the Crystallography Open Database. Theoretical simulation of the periodic structure of this new carbide predicts that it has hexagonal symmetry and a unit cell with a = 3.2A and c =2.8A. The exact structure is still uncertain but may be determined from scanning tunneling microscope (STM) studies.

  17. The microwave heating mechanism of N-(4-methoxybenzyliden)-4-butylaniline in liquid crystalline and isotropic phases as determined using in situ microwave irradiation NMR spectroscopy.

    PubMed

    Tasei, Yugo; Tanigawa, Fumikazu; Kawamura, Izuru; Fujito, Teruaki; Sato, Motoyasu; Naito, Akira

    2015-04-14

    Microwave heating effects are widely used in the acceleration of organic, polymerization and enzymatic reactions. These effects are primarily caused by the local heating induced by microwave irradiation. However, the detailed molecular mechanisms associated with microwave heating effects on the chemical reactions are not yet well understood. This study investigated the microwave heating effect of N-(4-methoxybenzylidene)-4-butylaniline (MBBA) in liquid crystalline and isotropic phases using in situ microwave irradiation nuclear magnetic resonance (NMR) spectroscopy, by obtaining (1)H NMR spectra of MBBA under microwave irradiation. When heated simply using the temperature control unit of the NMR instrument, the liquid crystalline MBBA was converted to the isotropic phase exactly at its phase transition temperature (Tc) of 41 °C. The application of microwave irradiation at 130 W for 90 s while maintaining the instrument temperature at 20 °C generated a small amount of isotropic phase within the bulk liquid crystal. The sample temperature of the liquid crystalline state obtained during microwave irradiation was estimated to be 35 °C by assessing the linewidths of the (1)H NMR spectrum. This partial transition to the isotropic phase can be attributed to a non-equilibrium local heating state induced by the microwave irradiation. The application of microwave at 195 W for 5 min to isotropic MBBA while maintaining an instrument temperature of 50 °C raised the sample temperature to 160 °C. In this study, the MBBA temperature during microwave irradiation was estimated by measuring the temperature dependent chemical shifts of individual protons in the sample, and the different protons were found to indicate significantly different temperatures in the molecule. These results suggest that microwave heating polarizes bonds in polar functional groups, and this effect may partly explain the attendant acceleration of organic reactions.

  18. Ionic liquid-based dispersive liquid-liquid microextraction followed high-performance liquid chromatography for the determination of organophosphorus pesticides in water sample.

    PubMed

    He, Lijun; Luo, Xianli; Xie, Hongxue; Wang, Chunjian; Jiang, Xiuming; Lu, Kui

    2009-11-23

    Using 1-octyl-3-methylimidazolium hexafluorophosphate ([C(8)MIM][PF(6)]) ionic liquid as extraction solvent, organophosphorus pesticides (OPPs) (parathion, phoxim, phorate and chlorpyifos) in water were determined by dispersive liquid-liquid microextraction (DLLME) combined with high-performance liquid chromatography (HPLC). The extraction procedure was induced by the formation of cloudy solution, which was composed of fine drops of [C(8)MIM][PF(6)] dispersed entirely into sample solution with the help of disperser solvent (methanol). Parameters including extraction solvent and its volume, disperser solvent and its volume, extraction time, centrifugal time, salt addition, extraction temperature and sample pH were investigated and optimized. Under the optimized conditions, up to 200-fold enrichment factor of analytes and acceptable extraction recovery (>70%) were obtained. The calibration curves were linear in the concentration range of 10.5-1045.0 microg L(-1) for parathion, 10.2-1020.0 microg L(-1) for phoxim, 54.5-1089.0 microg L(-1) for phorate and 27.2-1089.0 microg L(-1) for chlorpyifos, respectively. The limits of detection calculated at a signal-to-noise ratio of 3 were in the range of 0.1-5.0 microg L(-1). The relative standard deviations for seven replicate experiments at 200 microg L(-1) concentration level were less than 4.7%. The proposed method was applied to the analysis of four different sources water samples (tap, well, rain and Yellow River water) and the relative recoveries of spiked water samples are 99.9-115.4%, 101.8-113.7% and 87.3-117.6% at three different concentration levels of 75, 200 and 1000 microg L(-1), respectively.

  19. Phosphorus doping of 4H SiC by liquid immersion excimer laser irradiation

    SciTech Connect

    Ikeda, Akihiro; Nishi, Koji; Ikenoue, Hiroshi; Asano, Tanemasa

    2013-02-04

    Phosphorus doping of 4H SiC is performed by KrF excimer laser irradiation of 4H SiC immersed in phosphoric acid. Phosphorus is incorporated to a depth of a few tens of nanometers at a concentration of over 10{sup 20}/cm{sup 3} without generating significant crystal defects. Formation of a pn junction diode with an ideality factor of 1.06 is demonstrated.

  20. Effects of water chemistry on intergranular cracking of irradiated austenitic stainless steels

    SciTech Connect

    Chung, H.M.; Ruther, W.E.; Sanecki, J.E.; Hins, A.; Kassner, T.F.

    1995-12-31

    To determine the effects of water chemistry on the susceptibility to irradiation-assisted stress corrosion cracking (IASCC) in austenitic stainless steels, constant-extension-rate tests were conducted in simulated BWR environments on several heats of high- and commercial-purity (HP and CP) Type 304 SS specimens from BWR components irradiated to fluences up to 2.4 {times} 10{sup 21} n cm{sup {minus}2} (E > 1 MeV). Effects of dissolved oxygen (DO) and electrochemical potential (ECP) in 289 C water were investigated. Dependence of susceptibility to intergranular stress corrosion cracking (IGSCC) on DO was somewhat different for the two materials. Susceptibility of the HP heats, less influenced by DO and ECP, was higher than that of CP material for all DO and fluence levels. Percent IGSCC in the CP material was negligible for DO < 0.01 ppm or ECP <{minus}140 mV SHE. Results of analysis by Auger electron spectroscopy indicated that the HP neutron absorber tubes were characterized by relatively lower concentrations of Cr, Ni, and Li and relatively higher concentrations of F and N on grain boundaries than those of the CP materials. It is suggested that a synergism between irradiation-induced grain-boundary Cr depletion and fabrication-related fluorine contamination plays an important role in the stress corrosion cracking behavior of the HP neutron absorber tubes.

  1. The Discrepancy Between Measured and Modeled Downwelling Solar Irradiance at the Ground: Dependence on Water Vapor

    NASA Technical Reports Server (NTRS)

    Pilewskie, P.; Rabbette, M.; Bergstrom, R.; Marquez, J.; Schmid, B.; Russell, P. B.

    2000-01-01

    Moderate resolution spectra of the downwelling solar irradiance at the around in north central Oklahoma were measured during the Department of Energy Atmospheric Radiation Measurement Program Intensive Observation Period in the fall of 1997. Spectra obtained under cloud-free conditions were compared with calculations using a coarse resolution radiative transfer model to examine the dependency of model-measurement bias on water vapor. It was found that the bias was highly correlated with water vapor and increased at a rate of 9 W/sq m per cm of water. The source of the discrepancy remains undetermined because of the complex dependencies of other variables, most notably aerosol optical depth, on water vapor.

  2. The Discrepancy Between Measured and Modeled Downwelling Solar Irradiance at the Ground: Dependence on Water Vapor

    NASA Technical Reports Server (NTRS)

    Pilewskie, P.; Rabbette, M.; Bergstrom, R.; Marquez, J.; Schmid, B.; Russell, P. B.

    2000-01-01

    Moderate resolution spectra of the downwelling solar irradiance at the ground in north central Oklahoma were measured during the Department of Energy Atmospheric Radiation Measurement Program Intensive Observation Period in the fall of 1997. Spectra obtained under cloud-free conditions were compared with calculations using a coarse resolution radiative transfer model to examine the dependency of model-measurement bias on water vapor. It was found that the bias was highly correlated with water vapor and increased at a rate of 9 Wm(exp -2) per cm of water. The source of the discrepancy remains undetermined because of the complex dependencies of other variables, most notably aerosol optical depth, on water vapor.

  3. Fixed eruption due to quinine in tonic water: a case report with high-performance liquid chromatography and ultraviolet A analyses.

    PubMed

    Ohira, Aoi; Yamaguchi, Sayaka; Miyagi, Takuya; Yamamoto, Yu-Ichi; Yamada, Satoshi; Shiohira, Hideo; Hagiwara, Keisuke; Uno, Tsukasa; Uezato, Hiroshi; Takahashi, Kenzo

    2013-08-01

    Fixed drug eruption is a common cutaneous adverse reaction in young patients with a characteristic clinical appearance. However, the diagnosis and identification of the substance may be difficult if food or food additives provoke the fixed eruption. A 26-year-old man had a history of two episodes of cutaneous erythema with residual pigmentation. Close examination of the history including his diet in addition to an oral challenge test and patch testing led to the diagnosis of fixed eruption secondary to quinine in tonic water. We examined for the presence of quinine in commercially available brands of tonic water using ultraviolet A and irradiation and high-performance liquid chromatography. Both Schweppes and CANADA DRY brands of tonic water emitted fluorescent light upon ultraviolet A irradiation, and contained quinine at concentrations of 67.9 and 61.3 mg/L, respectively. Quinine contained in some tonic waters may trigger fixed eruption.

  4. Relationship between optical extinction and liquid water content in fogs

    NASA Astrophysics Data System (ADS)

    Klein, C.; Dabas, A.

    2014-05-01

    Studies carried out in the late 1970s suggest that a simple linear relationship exists in practice between the optical extinction in the thermal IR and the liquid water content (LWC) in fogs. Such a relationship opens the possibility to monitor the vertical profile of the LWC in fogs with a rather simple backscatter lidar. Little is known on how the LWC varies as a function of height and during the fog life cycle, so the new measurement technique would help understand fog physics and provide valuable data for improving the quality of fog forecasts. In this paper, the validity of the linear relationship is revisited in the light of recent observations of fog droplet size distributions measured with a combination of sensors covering a large range of droplet radii. In particular, large droplets (radius above 15 μm) are now detected, which was not the case in the late 1970s. The results confirm that the linear relationship still holds, at least for the mostly radiative fogs observed during the campaign. The impact of the precise value of the real and imaginary parts of the refractive index on the coefficient of the linear relationship is also studied. The usual practice considers that droplets are made of pure water. This assumption is probably valid for big drops, but it may be questioned for small ones since droplets are formed from condensation nuclei of highly variable chemical composition. The study suggests that the precise nature of condensation nuclei will primarily affect rather light fogs with small droplets and light liquid water contents.

  5. Ionic liquids for improving the extraction of NSAIDs in water samples using dispersive liquid-liquid microextraction by high performance liquid chromatography-diode array-fluorescence detection.

    PubMed

    Toledo-Neira, Carla; Álvarez-Lueje, Alejandro

    2015-03-01

    A rapid, sensitive and efficient analytical method based on the use of ionic liquids for determination of non-steroidal anti-inflammatory drugs (NSAIDs) in water samples was developed. High-performance liquid chromatography equipped with a diode array and fluorescence detector was used for quantification of ketoprofen, ibuprofen and diclofenac in tap and river water samples. This new method relies on the use of two ionic liquids with multiple functionalities: one functions as an extraction solvent (1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), and the other changes the polarity in the aqueous medium (1-butyl-3-methylimidazolium tetrafluoroborate, ([BMIM][BF4]). Factors such as the type and volume of the ILs and dispersive solvent, sample volume, and centrifugation time were investigated and optimized. The optimized method exhibited good precision, with relative standard deviation values between 2% and 3%, for the three NSAIDs. Limits of detection achieved for all of the analytes were between 17 and 95 ng mL(-1), and the recoveries ranged from 89% to 103%. Furthermore, the enrichment factors ranged from 49 to 57. The proposed method was successfully applied to the analysis of NSAIDs in tap and river water samples.

  6. Temporal changes in endmember abundances, liquid water and water vapor over vegetation at Jasper Ridge

    NASA Technical Reports Server (NTRS)

    Roberts, Dar A.; Green, Robert O.; Sabol, Donald E.; Adams, John B.

    1993-01-01

    Imaging spectrometry offers a new way of deriving ecological information about vegetation communities from remote sensing. Applications include derivation of canopy chemistry, measurement of column atmospheric water vapor and liquid water, improved detectability of materials, more accurate estimation of green vegetation cover and discrimination of spectrally distinct green leaf, non-photosynthetic vegetation (NPV: litter, wood, bark, etc.) and shade spectra associated with different vegetation communities. Much of our emphasis has been on interpreting Airborne Visible/Infrared Imaging Spectrometry (AVIRIS) data spectral mixtures. Two approaches have been used, simple models, where the data are treated as a mixture of 3 to 4 laboratory/field measured spectra, known as reference endmembers (EM's), applied uniformly to the whole image, to more complex models where both the number of EM's and the types of EM's vary on a per-pixel basis. Where simple models are applied, materials, such as NPV, which are spectrally similar to soils, can be discriminated on the basis of residual spectra. One key aspect is that the data are calibrated to reflectance and modeled as mixtures of reference EM's, permitting temporal comparison of EM fractions, independent of scene location or data type. In previous studies the calibration was performed using a modified-empirical line calibration, assuming a uniform atmosphere across the scene. In this study, a Modtran-based calibration approach was used to map liquid water and atmospheric water vapor and retrieve surface reflectance from three AVIRIS scenes acquired in 1992 over the Jasper Ridge Biological Preserve. The data were acquired on June 2nd, September 4th and October 6th. Reflectance images were analyzed as spectral mixtures of reference EM's using a simple 4 EM model. Atmospheric water vapor derived from Modtran was compared to elevation, and community type. Liquid water was compare to the abundance of NPV, Shade and Green Vegetation

  7. Simulated liquid water and visibility in stratiform boundary-layer clouds over sloping terrain

    SciTech Connect

    Tjernstroem, M. )

    1993-04-01

    The amount of liquid water in stratus clouds or fog is discussed from the point of view of estimating visibility variations in areas with complex terrain. The average vertical profile of liquid water from numerical simulations with a higher-order closure mesoscale model is examined, and runs with the model for moderately complex terrain are utilized to estimate the of low-level liquid water content variability and thus, indirectly, the variations in horizontal visibility along a slope. 37 refs., 11 figs.

  8. The Relationship Between Dynamics and Structure in the Far Infrared Absorption Spectrum of Liquid Water

    SciTech Connect

    Woods, K.

    2005-01-14

    Using an intense source of far-infrared radiation, the absorption spectrum of liquid water is measured at a temperature ranging from 269 to 323 K. In the infrared spectrum we observe modes that are related to the local structure of liquid water. Here we present a FIR measured spectrum that is sensitive to the low frequency (< 100cm{sup -1}) microscopic details that exist in liquid water.

  9. Mechanical Properties of Organic Materials Used in Superconducting Magnets Irradiated by Gamma Rays at Liquid Nitrogen Temperature

    SciTech Connect

    Nakamoto, T.; Kimura, N.; Makida, Y.; Ogitsu, T.; Ohhata, H.; Yamamoto, A.; Idesaki, A.; Morishita, N.; Itoh, H.; Kamiya, T.

    2006-03-31

    Radiation resistance of organic materials used in superconducting magnets for a 50 GeV-750 kW proton beam line for the J-PARC neutrino experiment was studied with respect to mechanical properties. Specimens cooled at a liquid nitrogen temperature of 77 K were irradiated by gamma rays from 60Co with the maximum dose beyond 10 MGy. The flexural strength of glass-fiber reinforced plastics (GFRPs), the tear strength of polyimide films and the tensile lap-shear strength of adhesive films were evaluated. It was verified that the organic materials used in the superconducting magnets have the sufficient radiation resistance, and the degradation of their mechanical properties after the 10 years operation was estimated to be negligible.

  10. Irradiation of a wide range of water ice samples in laboratory with electrons and heavy ions

    NASA Astrophysics Data System (ADS)

    Galli, André; Vorburger, Audrey; Pommerol, Antoine; Poch, Olivier; Wurz, Peter

    2017-04-01

    Airless bodies in space are subject to a continuous bombardment of charged particles from the plasma environment. This bombardment triggers chemical reactions in the surface and also acts as an atmospheric release process. The O2 atmosphere around Europa, e.g., probably is the result of magnetospheric O+ and S+ ions sputtering the surface ice. We experimentally investigate the interaction of charged particles with water ice by irradiating samples with electrons (0.1 - 10 keV) and ions (1 - 100 keV). The water ice samples are prepared with various techniques, resulting in 100 nm ice films or centimeter-thick icy regolith with a range of grain sizes. In this presentation, we summarize our results of all electron irradiation experiments. The results allow us to assess if sputtering due to electrons plays a role for the icy moons of Jupiter and Saturn compared to the better studied sputtering due to ions. We also will show our most recent results of multiply charged Ar+ ions and ionized molecules (O2+ for instance) impacting water ice. Finally, we compare the results from thin and compact ice films with those from more realistic deep and porous samples and their respective relevance for the study of water ice sputtering in the laboratory.

  11. Influence of liquid water and water vapor on antimisting kerosene (AMK)

    NASA Technical Reports Server (NTRS)

    Yavrouian, A. H.; Sarolouki, M.; Sarohia, V.

    1983-01-01

    Experiments have been performed to evaluate the compatibility of liquid water and water vapor with antimisting kerosenes (AMK) containing polymer additive FM-9 developed by Imperial Chemical Industries. This effort consists of the determination of water solubility in AMK, influence of water on restoration (degradation) of AMK, and effect of water on standard AMK quality control methods. The principal conclusions of this investigation are: (1) the uptake of water in AMK critically depends upon the degree of agitation and can be as high as 1300 ppm at 20 C, (2) more than 250 to 300 ppm of water in AMK causes an insoluble second phase to form. The amount of this second phase depends on fuel temperature, agitation, degree of restoration (degradation) and the water content of the fuel, (3) laboratory scale experiments indicate precipitate formation when water vapor comes in contact with cold fuel surfaces at a much lower level of water (125 to 150 ppm), (4) precipitate formation is very pronounced in these experiments where humid air is percolated through a cold fuel (-20 C), (5) laboratory tests further indicate that water droplet settling time is markedly reduced in AMK as compared to jet A, (6) limited low temperature testing down to -30 C under laboratory conditions indicates the formation of stable, transparent gels.

  12. Thermodynamics and quantum corrections from molecular dynamics for liquid water

    NASA Astrophysics Data System (ADS)

    Berens, Peter H.; Mackay, Donald H. J.; White, Gary M.; Wilson, Kent R.

    1983-09-01

    In principle, given the potential energy function, the values of thermodynamic variables can be computed from statistical mechanics for a system of molecules. In practice for the liquid state, however, two barriers must be overcome. This paper treats the first problem, how to quantum correct the classical mechanical thermodynamic values available from molecular dynamics, Monte Carlo, perturbation, or integral methods in order to compare with experimental quantum reality. A subsequent paper will focus on the second difficulty, the effective computation of free energy and entropy. A simple technique, derived from spectral analysis of the atomic velocity time histories, is presented here for the frequency domain quantum correction of classical thermodynamic values. This technique is based on the approximation that potential anharmonicities mainly affect the lower frequencies in the velocity spectrum where the system behaves essentially classically, while the higher spectral frequencies, where the deviation from classical mechanics is most pronounced, involve sufficiently harmonic atomic motions that harmonic quantum corrections apply. Thus, a harmonic quantum correction can be applied at all frequencies: at low frequencies where it is inaccurate it will be small, while at high frequencies where it is large it will also be relatively accurate. The approach is demonstrated by computation of the energy and constant volume heat capacity for water from classical molecular dynamics followed by quantum correction. The potential used to describe the interactions of the system of water molecules includes internal vibrational degrees of freedom and thus strong quantum effects. Comparison of the quantum corrected theoretical values with experimental measurements shows good agreement. The quantum corrections to classical thermodynamics (which are also derived for free energy and entropy) are shown to be important not only for internal vibrational motion, but also for

  13. Rapid and efficient functionalized ionic liquid-catalyzed aldol condensation reactions associated with microwave irradiation.

    PubMed

    Wang, Chang; Liu, Jing; Leng, Wenguang; Gao, Yanan

    2014-01-17

    Five quaternary ammonium ionic liquid (IL) and two tetrabutylphosphonium ILs were prepared and characterized. An environmentally benign and convenient functionalized ionic liquid catalytic system was thus explored in the aldol condensation reactions of aromatic aldehydes with acetone. The aldol reactions proceeded more efficiently through microwave-assisted heating than through conventional thermal heating. The yield of products obtained under microwave heating for 30 min was approximately 90%, and the ILs can be recovered and reused at least five times without apparent loss of activity. In addition, this catalytic system can be successfully extended to the Henry reactions.

  14. Rapid and Efficient Functionalized Ionic Liquid-Catalyzed Aldol Condensation Reactions Associated with Microwave Irradiation

    PubMed Central

    Wang, Chang; Liu, Jing; Leng, Wenguang; Gao, Yanan

    2014-01-01

    Five quaternary ammonium ionic liquid (IL) and two tetrabutylphosphonium ILs were prepared and characterized. An environmentally benign and convenient functionalized ionic liquid catalytic system was thus explored in the aldol condensation reactions of aromatic aldehydes with acetone. The aldol reactions proceeded more efficiently through microwave-assisted heating than through conventional thermal heating. The yield of products obtained under microwave heating for 30 min was approximately 90%, and the ILs can be recovered and reused at least five times without apparent loss of activity. In addition, this catalytic system can be successfully extended to the Henry reactions. PMID:24445262

  15. [The heavy ion irradiation influence on the thermodynamic parameters of liquids in human body].

    PubMed

    Vlasenko, T S; Bulavin, L A; Sysoev, V M

    2014-01-01

    In this manuscript a theoretical model describing the influence of the heavy ion radiotherapy on the liquid matter in the human body is suggested. Based on the fundamental equations of Bogoliubov chain the effective temperatures in the case of constant particles fluent are found in the context of single component model. An existence of such temperatures allows the use of equilibrium thermodynamics formalism to nonequilibrium stationary state. The obtained results provide the possibility of predicting the liquid matter structural changes in the biological systems in the area influenced by the heavy ion beams.

  16. Use of Spacecraft Data to Drive Regions on Mars where Liquid Water would be Stable

    NASA Technical Reports Server (NTRS)

    Lobitz, Brad; Wood, Byron L.; Averner, Maurice M.; McKay, Christopher P.; MacElroy, Robert D.

    2001-01-01

    Combining Viking pressure and temperature data with Mars Orbital Laser Altimeter (MOLA) topography data we have computed the fraction of the martian year during which pressure and temperature allow for liquid water to be stable on the martian surface. We find that liquid water would be stable within the Hellas and Argyre basin and over the northern lowlands equatorward of about 40 degrees. The location with the maximum period of stable conditions for liquid water is in the southeastern portion of Utopia Planitia where 34% of the year liquid water would be stable if it was present. Locations of stability appear to correlate with the distribution of valley networks.

  17. Use of spacecraft data to derive regions on Mars where liquid water would be stable

    PubMed Central

    Lobitz, Brad; Wood, Byron L.; Averner, Maurice M.; McKay, Christopher P.

    2001-01-01

    Combining Viking pressure and temperature data with Mars Orbital Laser Altimeter topography data, we have computed the fraction of the martian year during which pressure and temperature allow for liquid water to be stable on the martian surface. We find that liquid water would be stable within the Hellas and Argyre basin and over the northern lowlands equatorward of about 40°. The location with the maximum period of stable conditions for liquid water is in the southeastern portion of Utopia Planitia, where 34% of the year liquid water would be stable if it were present. Locations of stability appear to correlate with the distribution of valley networks. PMID:11226204

  18. Thermodynamic constraint on the cloud liquid water feedback in climate models

    NASA Technical Reports Server (NTRS)

    Betts, Alan K.; HARSHVARDHAN

    1987-01-01

    The cloud liquid water feedback in climate models consists of the increase (decrease) in optical depth of clouds resulting from higher (lower) liquid water contents that might accompany tropospheric warming (cooling). The change in cloud liquid water with temperature is shown to depend on the rate of change of the slope of the moist adiabat with respect to temperature, and it is a strong function of temperature. The value of this rate of change in the tropics is about half that in mid and high latitudes and is much less than the value obtained by assuming that liquid water scales with the saturation mixing ratio.

  19. A Simple Model to Quantify Radiolytic Production following Electron Emission from Heavy-Atom Nanoparticles Irradiated in Liquid Suspensions.

    PubMed

    Wardlow, Nathan; Polin, Chris; Villagomez-Bernabe, Balder; Currell, Fred

    2015-11-01

    We present a simple model for a component of the radiolytic production of any chemical species due to electron emission from irradiated nanoparticles (NPs) in a liquid environment, provided the expression for the G value for product formation is known and is reasonably well characterized by a linear dependence on beam energy. This model takes nanoparticle size, composition, density and a number of other readily available parameters (such as X-ray and electron attenuation data) as inputs and therefore allows for the ready determination of this contribution. Several approximations are used, thus this model provides an upper limit to the yield of chemical species due to electron emission, rather than a distinct value, and this upper limit is compared with experimental results. After the general model is developed we provide details of its application to the generation of HO• through irradiation of gold nanoparticles (AuNPs), a potentially important process in nanoparticle-based enhancement of radiotherapy. This model has been constructed with the intention of making it accessible to other researchers who wish to estimate chemical yields through this process, and is shown to be applicable to NPs of single elements and mixtures. The model can be applied without the need to develop additional skills (such as using a Monte Carlo toolkit), providing a fast and straightforward method of estimating chemical yields. A simple framework for determining the HO• yield for different NP sizes at constant NP concentration and initial photon energy is also presented.

  20. Water-mediated ion–ion interactions are enhanced at the water vapor–liquid interface

    PubMed Central

    Venkateshwaran, Vasudevan; Vembanur, Srivathsan; Garde, Shekhar

    2014-01-01

    There is overwhelming evidence that ions are present near the vapor–liquid interface of aqueous salt solutions. Charged groups can also be driven to interfaces by attaching them to hydrophobic moieties. Despite their importance in many self-assembly phenomena, how ion–ion interactions are affected by interfaces is not understood. We use molecular simulations to show that the effective forces between small ions change character dramatically near the water vapor–liquid interface. Specifically, the water-mediated attraction between oppositely charged ions is enhanced relative to that in bulk water. Further, the repulsion between like-charged ions is weaker than that expected from a continuum dielectric description and can even become attractive as the ions are drawn to the vapor side. We show that thermodynamics of ion association are governed by a delicate balance of ion hydration, interfacial tension, and restriction of capillary fluctuations at the interface, leading to nonintuitive phenomena, such as water-mediated like charge attraction. “Sticky” electrostatic interactions may have important consequences on biomolecular structure, assembly, and aggregation at soft liquid interfaces. We demonstrate this by studying an interfacially active model peptide that changes its structure from α-helical to a hairpin-turn–like one in response to charging of its ends. PMID:24889634

  1. The oxygen isotope partition function ratio of water and the structure of liquid water

    USGS Publications Warehouse

    O'Neil, J.R.; Adami, L.H.

    1969-01-01

    By means of the CO2-equilibration technique, the temperature dependence and absolute values of the oxygen isotope partition function ratio of liquid water have been determined, often at 1?? intervals, from -2 to 85??. A linear relationship between In (Q2/Q1) (H2O) and T-1 was obtained that is explicable in terms of the Bigeleisen-Mayer theory of isotopic fractionation. The data are incompatible with conventional, multicomponent mixture models of water because liquid water behaves isotopically as a singly structured homogeneous substance over the entire temperature range studied. A two-species model of water is proposed in which approximately 30% of the hydrogen bonds in ice are broken on melting at 0?? and in which this per cent of monomer changes by only a small amount over the entire liquid range. Because of the high precision and the fundamental property determined, the isotopic fractionation technique is particularly well suited to the detection of thermal anomalies. No anomalies were observed and those previously reported are ascribed to under-estimates of experimental error.

  2. One-step phenol production from a water-toluene mixture using radio frequency in-liquid plasma

    NASA Astrophysics Data System (ADS)

    Agung, Muhammad; Nomura, Shinfuku; Mukasa, Shinobu; Toyota, Hiromichi; Kazuhiko, Otsuka; Goto, Hidekazu

    2017-05-01

    The objectives of this research were to understand the process of converting toluene into phenol in a one-step process directly from a water-toluene mixture using the plasma in-liquid method. Experiments were conducted using 27.12 MHz radio frequency (RF) in-liquid plasma to decompose a solution of 30% toluene. Based on the experimental results as evaluated using gas chromatography-mass spectrometry (GC-MS), along with additional analysis by the Gaussian calculation, density functional theory (DFT) hybrid exchange-correlational functional (B3LYP) and 6-311G basis, the phenol generated from toluene was quantified including any by-products. In the experiment, it was found that OH radicals from water molecules produced using RF in-liquid plasma play a significant role in the chemical reaction with toluene. The experimental results suggest that phenol can be directly produced from a water-toluene mixture. The maximum phenol yields were 0.0013% and 0.0038% for irradiation times of 30 s and 60 s, respectively, at 120 W.

  3. Detachment of Liquid-Water Droplets from Gas-Diffusion Layers

    SciTech Connect

    Das, Prodip K.; Grippin, Adam; Weber, Adam Z.

    2011-07-01

    A critical issue for optimal water management in proton-exchange-membrane fuel cells at lower temperatures is the removal of liquid water from the cell. This pathway is intimately linked with the phenomena of liquid-water droplet removal from surface of the gas-diffusion layer and into the flow channel. Thus, a good understanding of liquid-water transport and droplet growth and detachment from the gas-diffusion layer is critical. In this study, liquid-water droplet growth and detachment on the gas-diffusion layer surfaces are investigated experimentally to improve the understating of water transport through and removal from gas-diffusion layers. An experiment using a sliding-angle measurement is designed and used to quantify and directly measure the adhesion force for liquid-water droplets, and to understand the droplets? growth and detachment from the gas-diffusion layers.

  4. EFFECT OF UV IRRADIATION ON ORGANIC MATTER EXTRACTED FROM TREATED OHIO RIVER WATER STUDIED THROUGH THE USE OF ELECTROSPRAY MASS SPECTROMETRY

    EPA Science Inventory

    Ohio River water was treated by settling, sand filtration, and granular activated carbon filtration. It was then irradiated by low pressure (monochromatic) and medium pressure (polychromatic) UV lamps to investigate the effects of UV irradiation of natural organic matter (NOM). ...

  5. EFFECT OF UV IRRADIATION ON ORGANIC MATTER EXTRACTED FROM TREATED OHIO RIVER WATER STUDIED THROUGH THE USE OF ELECTROSPRAY MASS SPECTROMETRY

    EPA Science Inventory

    Ohio River water was treated by settling, sand filtration, and granular activated carbon filtration. It was then irradiated by low pressure (monochromatic) and medium pressure (polychromatic) UV lamps to investigate the effects of UV irradiation of natural organic matter (NOM). ...

  6. Stability of uncapped gold nanoparticles produced by laser ablation in deionized water: The effect of post-irradiation

    NASA Astrophysics Data System (ADS)

    Kim, Kuk Ki; Kwon, Hye Jin; Shin, Seung Keun; Song, Jae Kyu; Park, Seung Min

    2013-11-01

    Gold nanoparticle (AuNP) solution prepared by laser ablation in liquid (LAL) was irradiated by ns laser pulses to investigate the wavelength dependence on the size distribution of AuNPs and long-term stability of post-irradiated AuNP solutions. We have employed 266, 355, 532, and 1064 nm lasers for post-irradiation source and found considerable wavelength dependence in the size distribution and stability of laser-generated AuNPs. Post-irradiation at 355 nm was most effective to reduce the size distribution and to enhance the stability. The classical Derjaguin-Landau-Verwey-Overbeek theory was employed to explain the anomalous stability at 355 nm.

  7. Phase transition model of water flow irradiated by high-energy laser in a chamber

    NASA Astrophysics Data System (ADS)

    Wei, Ji-Feng; Sun, Li-Qun; Zhang, Kai; Hu, Xiao-Yang

    2014-07-01

    In the absorption chamber of a high-energy laser energy meter, water is directly used as an absorbing medium and the interaction of the high-power laser and the water flow can produce a variety of physical phenomena such as phase transitions. The unit difference method is adopted to deduce the phase transition model for water flow irradiated by a high-energy laser. In addition, the model is simulated and verified through experiments. Among them, the experimental verification uses the photographic method, shooting the distribution and the form of the air mass of water flow in different operating conditions, which are compared with the simulation results. The research shows that it is achievable to reduce the intensity of the phase transition by increasing the water flow, reducing the power intensity of the beam, shortening the distance the beam covers, reducing the initial water temperature or adopting a shorter wavelength laser. The study's results will provide the reference for the design of a water-direct-absorption-type high-energy laser energy meter as well as an analysis of the interaction processes of other similar high-power lasers and water flow.

  8. Onset of simple liquid behaviour in modified water models

    SciTech Connect

    Prasad, Saurav; Chakravarty, Charusita

    2014-04-28

    The transition to simple liquid behaviour is studied in a set of modified hybrid water models where the potential energy contribution of the Lennard-Jones dispersion-repulsion contribution is progressively enhanced relative to the electrostatic contribution. Characteristics of simple liquid behaviour that indicate the extent to which a given system can be mapped onto an inverse power law fluid are examined, including configurational energy-virial correlations, functional form of temperature dependence of the excess entropy along isochores, and thermodynamic and excess entropy scaling of diffusivities. As the Lennard-Jones contribution to the potential energy function increases, the strength of the configurational energy-virial correlations increases. The Rosenfeld-Tarazona temperature dependence of the excess entropy is found to hold for the range of state points studied here for all the hybrid models, regardless of the degree of correlating character. Thermodynamic scaling is found to hold for weakly polar fluids with a moderate degree of energy-virial correlations. Rosenfeld-scaling of transport properties is found not to be necessarily linked with the strength of energy-virial correlations but may hold for systems with poor thermodynamic scaling if diffusivities and excess entropies show correlated departures from the isomorph-invariant behaviour characteristic of approximate inverse power law fluids. The state-point dependence of the configurational energy-virial correlation coefficient and the implications for thermodynamic and excess entropy scalings are considered.

  9. Onset of simple liquid behaviour in modified water models

    NASA Astrophysics Data System (ADS)

    Prasad, Saurav; Chakravarty, Charusita

    2014-04-01

    The transition to simple liquid behaviour is studied in a set of modified hybrid water models where the potential energy contribution of the Lennard-Jones dispersion-repulsion contribution is progressively enhanced relative to the electrostatic contribution. Characteristics of simple liquid behaviour that indicate the extent to which a given system can be mapped onto an inverse power law fluid are examined, including configurational energy-virial correlations, functional form of temperature dependence of the excess entropy along isochores, and thermodynamic and excess entropy scaling of diffusivities. As the Lennard-Jones contribution to the potential energy function increases, the strength of the configurational energy-virial correlations increases. The Rosenfeld-Tarazona temperature dependence of the excess entropy is found to hold for the range of state points studied here for all the hybrid models, regardless of the degree of correlating character. Thermodynamic scaling is found to hold for weakly polar fluids with a moderate degree of energy-virial correlations. Rosenfeld-scaling of transport properties is found not to be necessarily linked with the strength of energy-virial correlations but may hold for systems with poor thermodynamic scaling if diffusivities and excess entropies show correlated departures from the isomorph-invariant behaviour characteristic of approximate inverse power law fluids. The state-point dependence of the configurational energy-virial correlation coefficient and the implications for thermodynamic and excess entropy scalings are considered.

  10. Rapid conversion of sorbitol to isosorbide in hydrophobic ionic liquids under microwave irradiation.

    PubMed

    Kamimura, Akio; Murata, Kengo; Tanaka, Yoshiki; Okagawa, Tomoki; Matsumoto, Hiroshi; Kaiso, Kouji; Yoshimoto, Makoto

    2014-12-01

    Sorbitol was effectively converted to isosorbide by treatment with [TMPA][NTf2 ] in the presence of catalytic amounts of TsOH under microwave heating at 180 °C. The reaction completed within 10 min and isosorbide was isolated to about 60%. Ionic liquids were readily recovered by an extraction treatment and reused several times.

  11. Cloud Liquid Water, Mean Droplet Radius and Number Density Measurements Using a Raman Lidar

    NASA Technical Reports Server (NTRS)

    Whiteman, David N.; Melfi, S. Harvey

    1999-01-01

    A new technique for measuring cloud liquid water, mean droplet radius and droplet number density is outlined. The technique is based on simultaneously measuring Raman and Mie scattering from cloud liquid droplets using a Raman lidar. Laboratory experiments on liquid micro-spheres have shown that the intensity of Raman scattering is proportional to the amount of liquid present in the spheres. This fact is used as a constraint on calculated Mie intensity assuming a gamma function particle size distribution. The resulting retrieval technique is shown to give stable solutions with no false minima. It is tested using Raman lidar data where the liquid water signal was seen as an enhancement to the water vapor signal. The general relationship of retrieved average radius and number density is consistent with traditional cloud physics models. Sensitivity to the assumed maximum cloud liquid water amount and the water vapor mixing ratio calibration are tested. Improvements to the technique are suggested.

  12. Cloud Liquid Water, Mean Droplet Radius and Number Density Measurements Using a Raman Lidar

    NASA Technical Reports Server (NTRS)

    Whiteman, David N.; Melfi, S. Harvey

    1999-01-01

    A new technique for measuring cloud liquid water, mean droplet radius and droplet number density is outlined. The technique is based on simultaneously measuring Raman and Mie scattering from cloud liquid droplets using a Raman lidar. Laboratory experiments on liquid micro-spheres have shown that the intensity of Raman scattering is proportional to the amount of liquid present in the spheres. This fact is used as a constraint on calculated Mie intensity assuming a gamma function particle size distribution. The resulting retrieval technique is shown to give stable solutions with no false minima. It is tested using Raman lidar data where the liquid water signal was seen as an enhancement to the water vapor signal. The general relationship of retrieved average radius and number density is consistent with traditional cloud physics models. Sensitivity to the assumed maximum cloud liquid water amount and the water vapor mixing ratio calibration are tested. Improvements to the technique are suggested.

  13. In situ observation of axial irradiation growth in liquid-metal reactor metal fuel

    SciTech Connect

    Cramer, E.R.; Pitner, A.L.

    1989-01-01

    Effects of the rapid early-in-life expansion of metal fuel were measured in an irradiation experiment in the Fast Flux Test Facility (FFTF). This important performance/design information was obtainable through the unique combination of a dimensionally stable FFTF oxide core and the calibrated proximity instrumentation associated with the test. These results delineate the time dependence of metal-fuel swelling and provide quantitative estimates of the magnitude of axial fuel swelling in full-length metal-fuel assemblies. Final posttest examination results will define actual fuel column growth levels.

  14. Conversion of lignocellulosics pretreated with liquid hot water to ethanol

    SciTech Connect

    Walsum, G.P. van; Laser, M.S.; Lynd, L.R.

    1996-12-31

    Lignocellulosic materials pretreated using liquid hot water (LHW) (220{degrees}C, 5 MPa, 120 s) were fermented to ethanol by batch simultaneous saccharification and fermentation (SSF) using Saccharomyces cerevisiae in the presence of Trichoderma reesei cellulose. SSF of sugarcane bagasse (as received), aspen chips (smallest dimension 3 mm), and mixed hardwood flour (-60 +70 mesh) resulted in 90% conversion to ethanol in 2-5 d at enzyme loadings of 15-30 FPU/g. In most cases, 90% of the final conversion was achieved within 75 h of inoculation. Comminution of the pretreated substrates did not affect the conversion to ethanol. The hydrolysate produced from the LHW pretreatment showed slight inhibition of batch growth of S. cerevisiae. Solids pretreated at a concentration of 100 g/L were as reactive as those pretreated at a lower concentration, provided that the temperature was maintained at 220{degrees}C. 51 refs., 3 figs., 4 tabs.

  15. Electrokinetic Hydrogen Generation from Liquid WaterMicrojets

    SciTech Connect

    Duffin, Andrew M.; Saykally, Richard J.

    2007-05-31

    We describe a method for generating molecular hydrogen directly from the charge separation effected via rapid flow of liquid water through a metal orifice, wherein the input energy is the hydrostatic pressure times the volume flow rate. Both electrokinetic currents and hydrogen production rates are shown to follow simple equations derived from the overlap of the fluid velocity gradient and the anisotropic charge distribution resulting from selective adsorption of hydroxide ions to the nozzle surface. Pressure-driven fluid flow shears away the charge balancing hydronium ions from the diffuse double layer and carries them out of the aperture. Downstream neutralization of the excess protons at a grounded target electrode produces gaseous hydrogen molecules. The hydrogen production efficiency is currently very low (ca. 10-6) for a single cylindrical jet, but can be improved with design changes.

  16. Characterization and Modeling of a Water-based Liquid Scintillator

    SciTech Connect

    L. J. Bignell; Beznosko, D.; Diwan, M. V.; Hans, S.; Jaffe, D. E.; S. Kettell; Rosero, R.; Themann, H. W.; Viren, B.; Worcester, E.; Yeh, M.; Zhang, C.

    2015-12-15

    We characterised Water-based Liquid Scintillator (WbLS) using low energy protons, UV-VIS absorbance, and fluorescence spectroscopy. We have also developed and validated a simulation model that describes the behaviour of WbLS in our detector configurations for proton beam energies of 210 MeV, 475 MeV, and 2 GeV and for two WbLS compositions. These results have enabled us to estimate the light yield and ionisation quenching of WbLS, as well as to understand the influence of the wavelength shifting of Cherenkov light on our measurements. These results are relevant to the suitability of WbLS materials for next generation intensity frontier experiments.

  17. Atomistic simulations of liquid water using Lekner electrostatics

    NASA Astrophysics Data System (ADS)

    English, Niall J.; MacElroy, J. M. D.

    Equilibrium molecular dynamics simulations have been performed for liquid water using three different potential models in the NVT and NPT ensembles. The flexible SPC model, the rigid TIP4P model and the rigid/polarizable TIP4P-FQ potential were studied. The Lekner method was used to handle long range electrostatic interactions, and an efficient trivariate cubic spline interpolation method was devised for this purpose. A partitioning of the electrostatic interactions into medium and long range parts was performed, and the concomitant use of multiple timestep techniques led to substantially enhanced computation speeds. The simulations were carried out using 256 molecules in the NVT ensemble at 25°C and 997kgm-3 and in the NPT ensemble at 25°C and 1 bar. Various dynamic, structural, dielectric, rotational and thermodynamic properties were calculated, and it was found that the simulation methodologies performed satisfactorily vis-à-vis previous simulation results and experimental observations.

  18. Luminescence imaging of water during irradiation of X-ray photons lower energy than Cerenkov- light threshold

    NASA Astrophysics Data System (ADS)

    Yamamoto, Seiichi; Koyama, Shuji; Komori, Masataka; Toshito, Toshiyuki

    2016-10-01

    Luminescence imaging of water using X-ray photon irradiation at energy lower than maximum energy of ~200 keV is thought to be impossible because the secondary electrons produced in this energy range do not emit Cerenkov- light. Contrary to this consensus assumption, we show that the luminescence imaging of water can be achieved by X-ray irradiation at energy lower than 120 keV. We placed water phantoms on a table with a conventional X-ray imaging system, and luminescence images of these phantoms were measured with a high-sensitivity, cooled charge coupled device (CCD) camera during X-ray photon irradiation at energy below 120 keV. We also carried out such imaging of an acrylic block and plastic scintillator. The luminescence images of water phantoms taken during X-ray photon irradiation clearly showed X-ray photon distribution. The intensity of the X-ray photon images of the phantom increased almost proportionally to the number of X-ray irradiations. Lower-energy X-ray photon irradiation showed lower-intensity luminescence at the deeper parts of the phantom due to the higher X-ray absorption in the water phantom. Furthermore, lower-intensity luminescence also appeared at the deeper parts of the acrylic phantom due to its higher density than water. The intensity of the luminescence for water was 0.005% of that for plastic scintillator. Luminescence imaging of water during X-ray photon irradiation at energy lower than 120 keV was possible. This luminescence imaging method is promising for dose estimation in X-ray imaging systems.

  19. Removal of diclofenac from surface water by electron beam irradiation combined with a biological aerated filter

    NASA Astrophysics Data System (ADS)

    He, Shijun; Wang, Jianlong; Ye, Longfei; Zhang, Youxue; Yu, Jiang

    2014-12-01

    The degradation of DCF was investigated in aqueous solution by using electron beam (EB) technology. When the initial concentration was between 10 and 40 mg/L, almost 100% of the DCF was degraded at a dose of 0.5 kGy. However, only about 6.5% of DCF was mineralized even at 2 kGy according to total organic carbon (TOC) measurements. A combined process of EB and biological aerated filter (BAF) was therefore developed to enhance the treatment of DCF contaminated surface water. The effluent quality of combined process was substantially improved by EB pretreatment due to the degradation of DCF and related intermediates. Both irradiation and biological treatment reduced the toxicity of the treated water. The experimental results showed that EB is effective for removing DCF from artificial aqueous solution and real surface water.

  20. Deployment of Cesium Recovered from High Level Liquid Waste for Irradiation - Indian Scenario - 13128

    SciTech Connect

    Vincent, Tessy; Shah, J.G.; Kumar, Amar; Patil, S.B.; Wattal, P.K.

    2013-07-01

    Recovery of Cs-137 from HLW and its utilisation as source pencil in place of Co-60 is vital for medical and sewage treatment applications in India. For separation of Cs, specific ion exchange resins as well as 'Calyx crown' solvent have been developed and synthesized indigenously. A flow sheet involving separation of Cs from acidic HLW using Ammonium Molybdo Phosphate (AMP) resins, recovery of Cs from the loaded AMP column by dissolving it in alkali, ion exchange purification of Cs rich alkaline solution using Resorcinol-Formaldehyde Poly condensate (RF) resins and its elution in cesium nitrate form was developed and demonstrated. Solvent extraction route employing 0.03 Molar, 1-3-octyl oxy Calyx (4) arene crown-6 in 30% isodecyl alcohol and dodecane was also established using mixer settlers. Cesium lithium borosilicate glass based formulations have been considered as a glass matrix for Cs irradiation pencils. While choosing this vitreous matrix, attributes addressing maximum possible Cs-137 loading, low glass pouring temperature to minimise Cs volatility, reasonably good mechanical strength and good chemical durability have been considered. Recovered cesium nitrate solution was vitrified along with glass additives in an induction heated metallic melter and subsequently poured into 12 numbers of Cs irradiation pencils positioned on turn-table equipped with the load cell. The complete cycle involving recovery of Cs from HLW followed by its conversion into Cs pencil was demonstrated. (authors)

  1. Stabilization of lamellar oil-water liquid crystals by surfactant/ co-surfactant monolayers

    NASA Astrophysics Data System (ADS)

    Braganza, L. F.; Dubois, M.; Tabony, J.

    1989-03-01

    LIQUID crystals are divided into two main classes, thermotropic and lyotropic. Thermotropic liquid crystals are formed by melting, whereas lyotropic liquid crystals arise from the association of molecules, such as soap and water, that in general are not in themselves liquid crystalline. Thermotropic liquid crystals are used for liquid-crystal displays; lyotropic liquid crystals occur in living cells. Here we report a novel sequence of lyotropic liquid crystals comprising alternate layers of oil and water whose thickness varies linearly with the relative proportions of oil and water, and we have determined their structure using neutron diffraction methods. The oil and water layers are separated and stabilized by a monolayer film of surfactant and co-surfactant. The individual layers are typically a hundred ångströms or more in thickness, and total lamellar spacings of up to 1,000 Å were observed. This behaviour is difficult to describe in terms of the theories of colloid stability currently used to describe lyotropic liquid crystals. An understanding of the self-organization of such systems over such large distances would elucidate how long-range liquid-crystalline ordering arises in living cells. Moreover, thermotropic liquid crystals are expensive and chemically relatively unstable, and lamellar mesophases of the lyotopic type described here could lead to inexpensive, chemically stable liquid-crystalline materials suitable for industrial application.

  2. Inhalation radiotoxicity of irradiated thorium as a heavy water reactor fuel

    SciTech Connect

    Edwards, G.W.R.; Priest, N.D.; Richardson, R.B.

    2013-07-01

    The online refueling capability of Heavy Water Reactors (HWRs), and their good neutron economy, allows a relatively high amount of neutron absorption in breeding materials to occur during normal fuel irradiation. This characteristic makes HWRs uniquely suited to the extraction of energy from thorium. In Canada, the toxicity and radiological protection methods dealing with personnel exposure to natural uranium (NU) spent fuel (SF) are well-established, but the corresponding methods for irradiated thorium fuel are not well known. This study uses software to compare the activity and toxicity of irradiated thorium fuel ('thorium SF') against those of NU. Thorium elements, contained in the inner eight elements of a heterogeneous high-burnup bundle having LEU (Low-enriched uranium) in the outer 35 elements, achieve a similar burnup to NU SF during its residence in a reactor, and the radiotoxicity due to fission products was found to be similar. However, due to the creation of such inhalation hazards as U-232 and Th-228, the radiotoxicity of thorium SF was almost double that of NU SF after sufficient time has passed for the decay of shorter-lived fission products. Current radio-protection methods for NU SF exposure are likely inadequate to estimate the internal dose to personnel to thorium SF, and an analysis of thorium in fecal samples is recommended to assess the internal dose from exposure to this fuel. (authors)

  3. Robustly photogenerating H2 in water using FeP/CdS catalyst under solar irradiation

    NASA Astrophysics Data System (ADS)

    Cheng, Huanqing; Lv, Xiao-Jun; Cao, Shuang; Zhao, Zong-Yan; Chen, Yong; Fu, Wen-Fu

    2016-01-01

    Photosplitting water for H2 production is a promising, sustainable approach for solar-to-chemical energy conversion. However, developing low-cost, high efficient and stable photocatalysts remains the major challenge. Here we report a composite photocatalyst consisting of FeP nanoparticles and CdS nanocrystals (FeP/CdS) for photogenerating H2 in aqueous lactic acid solution under visible light irradiation. Experimental results demonstrate that the photocatalyst is highly active with a H2-evolution rate of 202000 μmol h-1 g-1 for the first 5 h (106000 μmol h-1 g-1 under natural solar irradiation), which is the best H2 evolution activity, even 3-fold higher than the control in situ photo-deposited Pt/CdS system, and the corresponding to an apparent quantum efficiency of over 35% at 520 nm. More important, we found that the system exhibited excellent stability and remained effective after more than 100 h in optimal conditions under visible light irradiation. A wide-ranging analysis verified that FeP effectively separates the photoexcited charge from CdS and showed that the dual active sites in FeP enhance the activity of FeP/CdS photocatalysts.

  4. Irradiation treatment of pharmaceutical and personal care products (PPCPs) in water and wastewater: An overview

    NASA Astrophysics Data System (ADS)

    Wang, Jianlong; Chu, Libing

    2016-08-01

    Pharmaceutical and personal care products (PPCPs), especially the pharmaceutically active compounds (PhACs) such as antibiotics and hormones have attracted great concerns worldwide for their persistence and potential threat to ecosystem and public health. This paper presents an overview on the ionizing irradiation-induced degradation of PPCPs in aqueous solution. Parameters that affect PPCPs degradation, such as the absorbed dose, solution pH, dose rate, water matrices and the presence of some inorganic ions and humic acid are evaluated. The mechanism and pathways of radiolytic degradation of PPCPs are reviewed. In many cases, PPCPs such as antibiotics and X-ray contrast agent could be removed completely by radiation, but a higher absorbed dose was needed for their mineralization and toxicity reduction. The combination of ionizing irradiation with other methods such as H2O2, ozonation and TiO2 nanoparticles could improve the degradation efficacy and reduce the cost. Ionizing irradiation is a promising alternative for degradation of PPCPs in aqueous solution.

  5. Robustly photogenerating H2 in water using FeP/CdS catalyst under solar irradiation

    PubMed Central

    Cheng, Huanqing; Lv, Xiao-Jun; Cao, Shuang; Zhao, Zong-Yan; Chen, Yong; Fu, Wen-Fu

    2016-01-01

    Photosplitting water for H2 production is a promising, sustainable approach for solar-to-chemical energy conversion. However, developing low-cost, high efficient and stable photocatalysts remains the major challenge. Here we report a composite photocatalyst consisting of FeP nanoparticles and CdS nanocrystals (FeP/CdS) for photogenerating H2 in aqueous lactic acid solution under visible light irradiation. Experimental results demonstrate that the photocatalyst is highly active with a H2-evolution rate of 202000 μmol h−1 g−1 for the first 5 h (106000 μmol h−1 g−1 under natural solar irradiation), which is the best H2 evolution activity, even 3-fold higher than the control in situ photo-deposited Pt/CdS system, and the corresponding to an apparent quantum efficiency of over 35% at 520 nm. More important, we found that the system exhibited excellent stability and remained effective after more than 100 h in optimal conditions under visible light irradiation. A wide-ranging analysis verified that FeP effectively separates the photoexcited charge from CdS and showed that the dual active sites in FeP enhance the activity of FeP/CdS photocatalysts. PMID:26818001

  6. Vapor and Gas-Bubble Growth Dynamics around Laser-Irradiated, Water-Immersed Plasmonic Nanoparticles.

    PubMed

    Wang, Yuliang; Zaytsev, Mikhail E; The, Hai Le; Eijkel, Jan C T; Zandvliet, Harold J W; Zhang, Xuehua; Lohse, Detlef

    2017-02-28

    Microbubbles produced by exposing water-immersed metallic nanoparticles to resonant light play an important role in emerging and efficient plasmonic-enhanced processes for catalytic conversion, solar energy harvesting, biomedical imaging, and cancer therapy. How do these bubbles form, and what is their gas composition? In this paper, the growth dynamics of nucleating bubbles around laser-irradiated, water-immersed Au plasmonic nanoparticles are studied to determine the exact origin of the occurrence and growth of these bubbles. The microbubbles' contact angle, footprint diameter, and radius of curvature were measured in air-equilibrated water (AEW) and degassed water (DGW) with fast imaging. Our experimental data reveals that the growth dynamics can be divided into two regimes: an initial bubble nucleation phase (regime I, < 10 ms) and, subsequently a bubble growth phase (regime II). The explosive growth in regime I is identical for AEW and DGW due to the vaporization of water. However, the slower growth in regime II is distinctly different for AEW and DGW, which is attributed to the uptake of dissolved gas expelled from the water around the hot nanoparticle. Our scaling analysis reveals that the bubble radius scales with time as R(t) ∝ t(1/6) for both AEW and DGW in the initial regime I, whereas in the later regime II it scales as R(t) ∝ t(1/3) for AEW and is constant for perfectly degassed water. These scaling relations are consistent with the experiments.

  7. In situ separation of root hydraulic redistribution of soil water from liquid and vapor transport

    Treesearch

    Jeffrey M. Warren; J. Renée Brooks; Maria I. Dragila; Frederick C. Meinzer

    2011-01-01

    Nocturnal increases in water potential and water content in the upper soil profile are often attributed to root water efflux, a process termed hydraulic redistribution (HR). However, unsaturated liquid or vapor flux of water between soil layers independent of roots also contributes to the daily recovery in water content, confounding efforts to determine the actual...

  8. Relationship between optical extinction and liquid water content in fogs

    NASA Astrophysics Data System (ADS)

    Klein, C.; Dabas, A.

    2013-11-01

    Studies carried out in the late 1970s suggest a simple linear relationship exists in practice between the optical extinction in the thermal IR and the liquid water content (LWC) in fogs. Such a relationship opens the possibility to monitor the vertical profile of the LWC in fogs with a rather simple backscatter lidar. Little is known on how the LWC varies as a function of height and during the fog life cycle, so the new measurement technique would help understand fog physics and provide valuable data for improving the quality of fog forecasts. In the present article, the validity of the linear relationship is revisited at the light of recent observations of fog droplet size distributions measured with a combination of sensors covering a large range of droplet radii. In particular, large droplets (radius above 15 μm) are detected, which was not the case in the late 1970s. The results confirm the linear relationship still holds, at least for the mostly radiative fogs observed during the campaign. The impact of the precise value of the real and imaginary parts of the refractive index on the coefficient of the linear relationship is also studied. The usual practice considers droplets are made of pure water. This assumption is probably valid for big droplets, it may be questioned for small ones since droplets are formed from condensation nuclei of highly variable chemical composition. The study suggests the relationship is mostly sensitive to the real part of the refractive index and the sensitivity grows with the size of fog droplets. However, large fog droplets are more likely to have an index close to that of water since they are mainly composed of water.

  9. Water-Filtered Infrared A Irradiation in Combination with Visible Light Inhibits Acute Chlamydial Infection

    PubMed Central

    Marti, Hanna; Koschwanez, Maria; Pesch, Theresa; Blenn, Christian; Borel, Nicole

    2014-01-01

    New therapeutic strategies are needed to overcome drawbacks in treatment of infections with intracellular bacteria. Chlamydiaceae are Gram-negative bacteria implicated in acute and chronic diseases such as abortion in animals and trachoma in humans. Water-filtered infrared A (wIRA) is short wavelength infrared radiation with a spectrum ranging from 780 to 1400 nm. In clinical settings, wIRA alone and in combination with visible light (VIS) has proven its efficacy in acute and chronic wound healing processes. This is the first study to demonstrate that wIRA irradiation combined with VIS (wIRA/VIS) diminishes recovery of infectious elementary bodies (EBs) of both intra- and extracellular Chlamydia (C.) in two different cell lines (Vero, HeLa) regardless of the chlamydial strain (C. pecorum, C. trachomatis serovar E) as shown by indirect immunofluorescence and titration by subpassage. Moreover, a single exposure to wIRA/VIS at 40 hours post infection (hpi) led to a significant reduction of C. pecorum inclusion frequency in Vero cells and C. trachomatis in HeLa cells, respectively. A triple dose of irradiation (24, 36, 40 hpi) during the course of C. trachomatis infection further reduced chlamydial inclusion frequency in HeLa cells without inducing the chlamydial persistence/stress response, as ascertained by electron microscopy. Irradiation of host cells (HeLa, Vero) neither affected cell viability nor induced any molecular markers of cytotoxicity as investigated by Alamar blue assay and Western blot analysis. Chlamydial infection, irradiation, and the combination of both showed a similar release pattern of a subset of pro-inflammatory cytokines (MIF/GIF, Serpin E1, RANTES, IL-6, IL-8) and chemokines (IL-16, IP-10, ENA-78, MIG, MIP-1α/β) from host cells. Initial investigation into the mechanism indicated possible thermal effects on Chlamydia due to irradiation. In summary, we demonstrate a non-chemical reduction of chlamydial infection using the combination of water

  10. Water-filtered infrared a irradiation in combination with visible light inhibits acute chlamydial infection.

    PubMed

    Marti, Hanna; Koschwanez, Maria; Pesch, Theresa; Blenn, Christian; Borel, Nicole

    2014-01-01

    New therapeutic strategies are needed to overcome drawbacks in treatment of infections with intracellular bacteria. Chlamydiaceae are Gram-negative bacteria implicated in acute and chronic diseases such as abortion in animals and trachoma in humans. Water-filtered infrared A (wIRA) is short wavelength infrared radiation with a spectrum ranging from 780 to 1400 nm. In clinical settings, wIRA alone and in combination with visible light (VIS) has proven its efficacy in acute and chronic wound healing processes. This is the first study to demonstrate that wIRA irradiation combined with VIS (wIRA/VIS) diminishes recovery of infectious elementary bodies (EBs) of both intra- and extracellular Chlamydia (C.) in two different cell lines (Vero, HeLa) regardless of the chlamydial strain (C. pecorum, C. trachomatis serovar E) as shown by indirect immunofluorescence and titration by subpassage. Moreover, a single exposure to wIRA/VIS at 40 hours post infection (hpi) led to a significant reduction of C. pecorum inclusion frequency in Vero cells and C. trachomatis in HeLa cells, respectively. A triple dose of irradiation (24, 36, 40 hpi) during the course of C. trachomatis infection further reduced chlamydial inclusion frequency in HeLa cells without inducing the chlamydial persistence/stress response, as ascertained by electron microscopy. Irradiation of host cells (HeLa, Vero) neither affected cell viability nor induced any molecular markers of cytotoxicity as investigated by Alamar blue assay and Western blot analysis. Chlamydial infection, irradiation, and the combination of both showed a similar release pattern of a subset of pro-inflammatory cytokines (MIF/GIF, Serpin E1, RANTES, IL-6, IL-8) and chemokines (IL-16, IP-10, ENA-78, MIG, MIP-1α/β) from host cells. Initial investigation into the mechanism indicated possible thermal effects on Chlamydia due to irradiation. In summary, we demonstrate a non-chemical reduction of chlamydial infection using the combination of water

  11. Doping of Ion Irradiated Polyethylenterephtalate from Water Solution of LiCl

    NASA Astrophysics Data System (ADS)

    Hnatowicz, V.; Vacík, J.; Ervená, J.; Vorík, V.; Rybka, V.; Fink, D.; Klett, R.

    1997-02-01

    Polyethylenterephtalate foils (10 m thick with the density of = 1.3 g cm - 3) were irradiated with 150 keV Ar+ ions to fluences from 5×1011 to 1×1015 cm - 2 and one year after the irradiation they were exposed to a 5 M water solution of LiCl at the boiling point for times ranging from 15 s up to 8 h. The depth profiles of incorporated Li atoms as a function of the ion fluence and the doping time were determined using the neutron depth profiling technique based on the 6Li(nth, α)3H nuclear reaction. The Li content in the 600 nm thick surface layer achieves saturation very rapidly, already after 15 s doping time, and it exhibits a local, pronounced maximum at 2 or 4 h doping times for the specimens irradiated to fluences below and above 5×1014 cm - 2, respectively. The concentration depth profiles of incorporated Li atoms consist of a pronounced surface component, obviously connected with radiation damages created by the ion irradiation and a long inward tail which is due to regular diffusion in pristine polymer. As a function of ion fluence, the Li content increases up to the fluence of 5×1013 cm - 2 and then declines in most cases. The surface component of the Li depth profiles changes dramatically with increasing ion fluence from bell-shaped ones for fluences below 5×1014 cm×2 to those characterized by a depleted surface layer and a rather sharp concentration maximum at depths significantly exceeding the calculated ion projected range.

  12. Effectiveness of Liquid-Liquid Extraction, Solid Phase Extraction, and Headspace Technique for Determination of Some Volatile Water-Soluble Compounds of Rose Aromatic Water.

    PubMed

    Canbay, Hale Seçilmiş

    2017-01-01

    Steam distillation is used to isolate scent of rose flowers. Rose aromatic water is commonly used in European cuisine and aromatherapy besides its use in cosmetic industry for its lovely scent. In this study, three different sampling techniques, liquid-liquid extraction (LLE), headspace technique (HS), and solid phase extraction (SPE), were compared for the analysis of volatile water-soluble compounds in commercial rose aromatic water. Some volatile water-soluble compounds of rose aromatic water were also analyzed by gas chromatography mass spectrometry (GCMS). In any case, it was concluded that one of the solid phase extraction methods led to higher recoveries for 2-phenylethyl alcohol (PEA) in the rose aromatic water than the liquid-liquid extraction and headspace technique. Liquid-liquid extraction method provided higher recovery ratios for citronellol, nerol, and geraniol than others. Ideal linear correlation coefficient values were observed by GCMS for quantitative analysis of volatile compounds (r(2) ≥ 0.999). Optimized methods showed acceptable repeatability (RSDs < 5%) and excellent recovery (>95%). For compounds such as α-pinene, linalool, β-caryophyllene, α-humulene, methyl eugenol, and eugenol, the best recovery values were obtained with LLE and SPE.

  13. Effectiveness of Liquid-Liquid Extraction, Solid Phase Extraction, and Headspace Technique for Determination of Some Volatile Water-Soluble Compounds of Rose Aromatic Water

    PubMed Central

    2017-01-01

    Steam distillation is used to isolate scent of rose flowers. Rose aromatic water is commonly used in European cuisine and aromatherapy besides its use in cosmetic industry for its lovely scent. In this study, three different sampling techniques, liquid-liquid extraction (LLE), headspace technique (HS), and solid phase extraction (SPE), were compared for the analysis of volatile water-soluble compounds in commercial rose aromatic water. Some volatile water-soluble compounds of rose aromatic water were also analyzed by gas chromatography mass spectrometry (GCMS). In any case, it was concluded that one of the solid phase extraction methods led to higher recoveries for 2-phenylethyl alcohol (PEA) in the rose aromatic water than the liquid-liquid extraction and headspace technique. Liquid-liquid extraction method provided higher recovery ratios for citronellol, nerol, and geraniol than others. Ideal linear correlation coefficient values were observed by GCMS for quantitative analysis of volatile compounds (r2 ≥ 0.999). Optimized methods showed acceptable repeatability (RSDs < 5%) and excellent recovery (>95%). For compounds such as α-pinene, linalool, β-caryophyllene, α-humulene, methyl eugenol, and eugenol, the best recovery values were obtained with LLE and SPE. PMID:28791049

  14. Local Environment Distribution in Ab Initio Liquid Water

    NASA Astrophysics Data System (ADS)

    Santra, Biswajit; Distasio, Robert A., Jr.; Car, Roberto

    2013-03-01

    We have analyzed the distribution of local environments in liquid water at ambient conditions and its inherent potential energy surface (IPES) based on state-of-the-art ab initio molecular dynamics simulations performed on 128 molecules implementing hybrid PBE0 exchange [PRB 79, 085102 (2009)] and van der Waals (vdW) interactions [PRL 102, 073005 (2009)]. The local environments of molecules are characterized in terms of the local structure index (LSI) [JCP 104, 7671 (1996)] which is able to distinguish high- and low-density molecular environments. In agreement with simulations based on model potentials, we find that the distribution of LSI is unimodal at ambient conditions and bimodal in the IPES, consistent with the existence of polymorphism in amorphous phases of water. At ambient conditions spatial LSI fluctuations extend up to ~7 Å and their dynamical correlation decays on a time scale of ~3 ps, as found for density fluctuations in a recent study [PRL 106, 037801 (2011)]. DOE: DE-SC0008626, DOE: DE-SC0005180, NSF: CHE-0956500

  15. Why does hydronium diffuse faster than hydroxide in liquid water?

    NASA Astrophysics Data System (ADS)

    Zheng, Lixin; Santra, Biswajit; Distasio, Robert; Klein, Michael; Car, Roberto; Wu, Xifan

    Experiments show that the hydronium ion (H3O+) diffuses much faster than the hydroxide ion (OH-) in liquid water. ab initio molecular dynamics (AIMD) simulations correctly associated the diffusion mechanism to proton transfer (PT) but have been unable so far to clearly identify the reason for the faster diffusion of hydronium compared to hydroxide, as the diffusion rate was found to depend sensitively on the adopted functional approximation. We carried out AIMD simulations of the solvated water ions using a van der Waals (vdW) inclusive PBE0 hybrid density functional. It is found that not only hydronium diffuses faster than hydroxide but also the absolute rates agree with experiment. The fast diffusion of H3O+ occurs via concerted PT that enables the ion to jump across several H-bonded molecules in successful transfer events; in contrast, such concerted motion is significantly hindered in OH- where the ion is easily trapped in a hyper-coordination configuration (a local solvation structure that forbids PT). As a result multiple PT events are rare and the diffusion of OH- is significantly slowed down. Such a clear difference between the two ions results from the combined effect of vdW interactions and self-interaction correction. Doe SciDac: DE-SC0008626 and DE-SC0008726.

  16. Learning Science Through Guided Discovery: Liquid Water and Molecular Networks

    NASA Astrophysics Data System (ADS)

    Essmann, U.; Glotzer, S.; Gyure, M.; Ostrovsky, B.; Poole, P. H.; Sastry, S.; Schwarzer, S.; Selinger, R.; Shann, M. H.; Shore, L. S.; Stanley, H. E.; Taylor, E. F.; Trunfio, P.

    In every drop of water, down at the scale of atoms and molecules, there is a world that can fascinate anyone—ranging from a non-verbal young science student to an ardent science-phobe. The objective of Learning Science through Guided Discovery: Liquid Water and Molecular Networks is to use advanced technology to provide a window into this submicroscopic world, and thereby allow students to discover by themselves a new world. We have developed a coordinated two-fold approach in which a cycle of hands-on activities, games, and experimentation is followed by a cycle of advanced computer simulations employing the full power of computer animation to "ZOOM" into the depths of his or her newly-discovered world, an interactive experience surpassing that of an OMNIMAX theater. Pairing of laboratory experiments with corresponding simulations challenges students to understand multiple representations of concepts. Answers to student questions, resolution of student misconceptions, and eventual personalized student discoveries are all guided by a clear set of "cues" which we build into the computer display. We thereby provide students with the opportunity to work in a fashion analogous to that in which practicing scientists work—e.g., by using advanced technology to "build up" to general principles from specific experiences. Moreover, the ability to visualize "real-time" dynamic motions allows for student-controlled animated graphic simulations on the molecular scale and interactive guided lessons superior to those afforded by even the most artful of existing texts.

  17. Network analysis of proton transfer in liquid water

    SciTech Connect

    Shevchuk, Roman; Rao, Francesco; Agmon, Noam

    2014-06-28

    Proton transfer in macromolecular systems is a fascinating yet elusive process. In the last ten years, molecular simulations have shown to be a useful tool to unveil the atomistic mechanism. Notwithstanding, the large number of degrees of freedom involved make the accurate description of the process very hard even for the case of proton diffusion in bulk water. Here, multi-state empirical valence bond molecular dynamics simulations in conjunction with complex network analysis are applied to study proton transfer in liquid water. Making use of a transition network formalism, this approach takes into account the time evolution of several coordinates simultaneously. Our results provide evidence for a strong dependence of proton transfer on the length of the hydrogen bond solvating the Zundel complex, with proton transfer enhancement as shorter bonds are formed at the acceptor site. We identify six major states (nodes) on the network leading from the “special pair” to a more symmetric Zundel complex required for transferring the proton. Moreover, the second solvation shell specifically rearranges to promote the transfer, reiterating the idea that solvation beyond the first shell of the Zundel complex plays a crucial role in the process.

  18. Direct Raman evidence for a weak continuous phase transition in liquid water.

    PubMed

    Alphonse, Natalie K; Dillon, Stephanie R; Dougherty, Ralph C; Galligan, Dawn K; Howard, Louis N

    2006-06-22

    This paper presents the Raman depolarization ratio of degassed ultrapure water as a function of temperature, in the range 303.4-314.4 K (30.2-41.2 degrees C). The pressure of the sample was the vapor pressure of water at the measurement temperature. The data provide a direct indication of the existence of a phase transition in the liquid at 307.7 K, 5.8 kPa (34.6 degrees C, 0.057 atm). The minimum in the heat capacity, C(p)(), of water occurs at 34.5 degrees C, 1.0 atm (J. Res. Natl. Bur. Stand. 1939, 23, 197(1)). The minimum in C(p)() is shallow, and the transition is a weak-continuous phase transition. The pressure coefficient of the viscosity of water changes sign as pressure increases for temperatures below 35 degrees C (Nature 1965, 207, 620(2)). The viscosity minimum tracks the liquid phase transition in the P, T plane where it connects with the minimum in the freezing point of pure water in the same plane (Proc. Am. Acad. Arts Sci. 1911-12, 47, 441(3)). Previously we argued (J. Chem. Phys. 1998, 109, 7379(4)) that the minimum in the pressure coefficient of viscosity signaled the elimination of three-dimensional connectivity in liquid water. These observations coupled with recent measurements of the coordination shell of water near 300 K (Science 2004, 304, 995(5)) suggest that the structural component that changes during the phase transition is tetrahedrally coordinated water. At temperatures above the transition, there is no tetrahedrally coordinated water in the liquid and locally planar water structures dominate the liquid structure. Water is a structured liquid with distinct local structures that vary with temperature. Furthermore, liquid water has a liquid-liquid phase transition near the middle of the normal liquid range.

  19. Bright and multicolor luminescent colloidal Si nanocrystals prepared by pulsed laser irradiation in liquid

    SciTech Connect

    Nakamura, Toshihiro Watanabe, Kanta; Adachi, Sadao; Yuan, Ze

    2016-01-11

    We reported the preparation of bright and multicolor luminescent colloidal Si nanocrystal (Si-nc) by pulsed UV laser irradiation to porous Si (PSi) in an organic solvent. The different-luminescence-color (different-sized) colloidal Si-nc was produced by the pulsed laser-induced fragmentation of different-sized porous nanostructures. The colloidal Si-nc samples were found to have higher photoluminescence quantum efficiencies (20%–23%) than the PSi samples (1%–3%). The brighter emission of the colloidal Si-nc was attributed to an enhanced radiative band-to-band transition rate due to the presence of a surface organic layer formed by UV laser-induced hydrosilylation.

  20. Isobaric vapor-liquid equilibria for methanol + ethanol + water and the three constituent binary systems

    SciTech Connect

    Kurihara, Kiyofumi; Nakamichi, Mikiyoshi; Kojima, Kazuo . Dept. of Industrial Chemistry)

    1993-07-01

    Vapor-liquid equilibrium data for methanol + ethanol + water and its three constituent binary systems methanol + ethanol, ethanol + water, and methanol + water were measured at 101.3 kPa using a liquid-vapor ebullition-type equilibrium still. The experimental binary data were correlated by the NRTL equation. The ternary system methanol + ethanol + water was predicted by means of the binary NRTL parameters with good accuracy.

  1. Investigation of the Extinguishing Features for Liquid Fuels and Organic Flammable Liquids Atomized by a Water Flow

    NASA Astrophysics Data System (ADS)

    Voytkov, Ivan V.; Zabelin, Maksim V.; Vysokomornaya, Olga V.

    2016-02-01

    The processes of heat and mass transfer were investigated experimentally while moving and evaporating the atomized water flow in high-temperature combustion products of typical liquid fuels and organic flammable liquids: gasoline, kerosene, acetone, crude oil, industrial alcohol. We determined typical periods of liquid extinguishing by an atomized water flow of various dispersability. Data of the discharge of extinguishing medium corresponding to various parameters of atomization and duration of using the atomization devices was presented. It is shown that Um≈3.5 m/s is a minimal outflow velocity of droplets during moving while passing the distance of 1m in the high-temperature gas medium to stop the combustion of organic liquids.

  2. Investigation of by-product formation during the irradiation of drinking water with a medium pressure lamp.

    PubMed

    Couvert, A; Grandguillot, G; Féliers, C

    2007-08-01

    The goal of this study was to determine the effect of UV irradiation with a polychromatic spectrum on natural organic matter. Several irradiation tests were carried out with or without cut-off of wavelengths lower than 240 nm on water samples coming from different drinking water plants. DOC, BDOC, SEC analyses, chlorine demand, nitrate and nitrite concentration measurements were made. Changes were noticed as regarding SEC and chlorine demand analyses. Indeed a consistent trend of breaking-up NOM molecules into smaller fragments was observed. Moreover, the chlorine demand increased with the dose when the cut-off filter was not applied, whereas a maximum value resulted when the cut-off filter was applied. Most of these results were obtained at high UV doses (40000 J x m(-2)), suggesting that UV irradiation would not have a noticeable effect on the water samples tested at doses usually used for drinking water treatment.

  3. Low intensity electromagnetic irradiation with 70.6 and 73 GHz frequencies affects Escherichia coli growth and changes water properties.

    PubMed

    Torgomyan, Heghine; Kalantaryan, Vitaly; Trchounian, Armen

    2011-07-01

    The low intensity electromagnetic irradiation (EMI) of the 70.6 and 73 GHz frequency is resonant for Escherichia coli but not for water. In this study, E. coli irradiation with this EMI during 1 h directly and in bi-distilled water or in the assay buffer with those frequencies resulted with noticeable changes in bacterial growth parameters. Furthermore, after EMI, 2 h rest of bacteria renewed their growth in 1.2-fold, but repeated EMI--had no significant action. Moreover, water absorbance, pH, and electric conductance were changed markedly after such irradiation. The results point out that EMI of the 70.6 and 73 GHz frequency can interact with bacteria affecting growth and in the same time with the surrounding medium (water) as well.

  4. Further evaluations of the toxicity of irradiated advanced heavy water reactor fuels.

    PubMed

    Edwards, Geoffrey W R; Priest, Nicholas D

    2014-11-01

    The neutron economy and online refueling capability of heavy water moderated reactors enable them to use many different fuel types, such as low enriched uranium, plutonium mixed with uranium, or plutonium and/or U mixed with thorium, in addition to their traditional natural uranium fuel. However, the toxicity and radiological protection methods for fuels other than natural uranium are not well established. A previous paper by the current authors compared the composition and toxicity of irradiated natural uranium to that of three potential advanced heavy water fuels not containing plutonium, and this work uses the same method to compare irradiated natural uranium to three other fuels that do contain plutonium in their initial composition. All three of the new fuels are assumed to incorporate plutonium isotopes characteristic of those that would be recovered from light water reactor fuel via reprocessing. The first fuel investigated is a homogeneous thorium-plutonium fuel designed for a once-through fuel cycle without reprocessing. The second fuel is a heterogeneous thorium-plutonium-U bundle, with graded enrichments of U in different parts of a single fuel assembly. This fuel is assumed to be part of a recycling scenario in which U from previously irradiated fuel is recovered. The third fuel is one in which plutonium and Am are mixed with natural uranium. Each of these fuels, because of the presence of plutonium in the initial composition, is determined to be considerably more radiotoxic than is standard natural uranium. Canadian nuclear safety regulations require that techniques be available for the measurement of 1 mSv of committed effective dose after exposure to irradiated fuel. For natural uranium fuel, the isotope Pu is a significant contributor to the committed effective dose after exposure, and thermal ionization mass spectrometry is sensitive enough that the amount of Pu excreted in urine is sufficient to estimate internal doses, from all isotopes, as low

  5. Which shape characteristics of the intermolecular interaction of liquid water determine its compressibility ?

    NASA Astrophysics Data System (ADS)

    Yasutomi, Makoto

    2016-05-01

    We consider a fluid of spherical particles with a pair potential given by a hard core repulsion and a tail, and show that the isothermal compressibility of liquid water is determined by the degree of steepness of the soft repulsion near the hard-core contact. This helps us understand the thermodynamic mechanism that causes the compressibility anomaly of liquid water.

  6. ASSESSMENT OF THE LIQUID WATER CONTENT OF SUMMERTIME AEROSOL IN THE SOUTHEAST UNITED STATES

    EPA Science Inventory

    The concentration of aerosol liquid water mass represents an important parameter for understanding the physical properties of PM2.5 in the atmosphere. Increases in ambient relative humidity can increase aerosol liquid water and thus the composite particle mass and particle volu...

  7. ASSESSMENT OF THE LIQUID WATER CONTENT OF SUMMERTIME AEROSOL IN THE SOUTHEAST UNITED STATES

    EPA Science Inventory

    The concentration of aerosol liquid water mass represents an important parameter for understanding the physical properties of PM2.5 in the atmosphere. Increases in ambient relative humidity can increase aerosol liquid water and thus the composite particle mass and particle volu...

  8. Ephemeral liquid water at the surface of the martian North Polar Residual Cap: Results of numerical modelling

    NASA Astrophysics Data System (ADS)

    Losiak, Anna; Czechowski, Leszek; Velbel, Michael A.

    2015-12-01

    Gypsum, a mineral that requires water to form, is common on the surface of Mars. Most of it originated before 3.5 Gyr when the Red Planet was more humid than now. However, occurrences of gypsum dune deposits around the North Polar Residual Cap (NPRC) seem to be surprisingly young: late Amazonian in age. This shows that liquid water was present on Mars even at times when surface conditions were as cold and dry as the present-day. A recently proposed mechanism for gypsum formation involves weathering of dust within ice (e.g., Niles, P.B., Michalski, J. [2009]. Nat. Geosci. 2, 215-220.). However, none of the previous studies have determined if this process is possible under current martian conditions. Here, we use numerical modelling of heat transfer to show that during the warmest days of the summer, solar irradiation may be sufficient to melt pure water ice located below a layer of dark dust particles (albedo ⩽ 0.13) lying on the steepest sections of the equator-facing slopes of the spiral troughs within martian NPRC. During the times of high irradiance at the north pole (every 51 ka; caused by variation of orbital and rotational parameters of Mars e.g., Laskar, J. et al. [2002]. Nature 419, 375-377.) this process could have taken place over larger parts of the spiral troughs. The existence of small amounts of liquid water close to the surface, even under current martian conditions, fulfils one of the main requirements necessary to explain the formation of the extensive gypsum deposits around the NPRC. It also changes our understanding of the degree of current geological activity on Mars and has important implications for estimating the astrobiological potential of Mars.

  9. Effect of 3-D instrument casing shape on the self-shading of in-water upwelling irradiance.

    PubMed

    Piskozub, Jacek

    2004-07-12

    The self-shading measurement error of the upwelling irradiance caused by the presence of a typical cylindrical housing of an optical instrument was calculated with the 3-D Monte-Carlo code as a function of the housing dimensions and of the optical parameters of seawater. The resulting values were compared to the self-shading error for a flat disk of the same diameter, originally used to establish self-shading error estimations universally used in marine optics. The results show that the self-shading of upwelling irradiance is underestimated by up to 25% producing a significant underestimation of the measured upwelling irradiance, and therefore reflectance, especially in turbid waters.

  10. Effect of 3-D instrument casing shape on the self-shading of in-water upwelling irradiance

    NASA Astrophysics Data System (ADS)

    Piskozub, Jacek

    2004-07-01

    The self-shading measurement error of the upwelling irradiance caused by the presence of a typical cylindrical housing of an optical instrument was calculated with the 3-D Monte-Carlo code as a function of the housing dimensions and of the optical parameters of seawater. The resulting values were compared to the self-shading error for a flat disk of the same diameter, originally used to establish self-shading error estimations universally used in marine optics. The results show that the self-shading of upwelling irradiance is underestimated by up to 25% producing a significant underestimation of the measured upwelling irradiance, and therefore reflectance, especially in turbid waters.

  11. Model for the structure of the liquid water network

    SciTech Connect

    Grunwald, E.

    1986-09-17

    The state of a water molecule in liquid water is defined by its time-average network environment. Two states are characterized. State A is the familiar four-coordinated state of the Bernal-Fowler model with tetrahedral hydrogen bonds. State B is five-coordinated. Reexamination of the static dielectric constant by the method of Oster and Kirkwood confirms the marked polar character of the four-coordinated state but shows that the five-coordinated state is only about half as polar. Explicit five-coordinated models are proposed which are consistent with polarity and satisfy constraints of symmetry and hydrogen-bond stoichiometry. The potential energy due to the dipole-dipole interaction of the central water molecule with its time-average solvent network is derived without additional parameters. This permits prediction of barriers to rotation, frequencies for hindered rotation and liberation in the network, and ..delta..H/sub A,B/ and ..delta..S/sub A,B/. The results are in substantial agreement with relevant experiments. In particular, the barriers to rotation permit a consistent interpretation of the dielectric relaxation spectrum. The relative importance of the two states varies predictably with the property being examined, and this can account for some of the schizophrenia of aqueous properties. Since the two-state model is based on time-average network configurations, it does not apply when the time scale of observation is short compared to network frequencies, i.e., at infrared frequencies where continuum models may be successful.

  12. Ultrapreconcentration and determination of organophosphorus pesticides in water by solid-phase extraction combined with dispersive liquid-liquid microextraction and high-performance liquid chromatography.

    PubMed

    Chen, Junhua; Zhou, Guangming; Deng, Yongli; Cheng, Hongmei; Shen, Jie; Gao, Yi; Peng, Guilong

    2016-01-01

    Solid-phase extraction coupled with dispersive liquid-liquid microextraction was developed as an ultra-preconcentration method for the determination of four organophosphorus pesticides (isocarbophos, parathion-methyl, triazophos and fenitrothion) in water samples. The analytes considered in this study were rapidly extracted and concentrated from large volumes of aqueous solutions (100 mL) by solid-phase extraction coupled with dispersive liquid-liquid microextraction and then analyzed using high performance liquid chromatography. Experimental variables including type and volume of elution solvent, volume and flow rate of sample solution, salt concentration, type and volume of extraction solvent and sample solution pH were investigated for the solid-phase extraction coupled with dispersive liquid-liquid microextraction with these analytes, and the best results were obtained using methanol as eluent and ethylene chloride as extraction solvent. Under the optimal conditions, an exhaustive extraction for four analytes (recoveries >86.9%) and high enrichment factors were attained. The limits of detection were between 0.021 and 0.15 μg/L. The relative standard deviations for 0.5 μg/L of the pesticides in water were in the range of 1.9-6.8% (n = 5). The proposed strategy offered the advantages of simple operation, high enrichment factor and sensitivity and was successfully applied to the determination of four organophosphorus pesticides in water samples. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Evidence for Recent Liquid Water on Mars: Gullies

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Gully landforms proposed to have been caused by geologically-recent seepage and runoff of liquid water on Mars are found in the most unlikely places. They typically occur in areas that are quite cold, well below freezing all year round. Like the old adage about moss on trees, nearly all of them form on slopes that face away from sunlight. Most of the gullies occur at latitudes between 30 and 70. The highest latitude at which martian gullies have been found is around 70-75 S on the walls of pits developed in the south polar pitted plains. If you were at this same latitude on Earth, you would be in Antarctica. This region spends much of the winter--which lasts approximately 6 months on Mars--in darkness and at temperatures cold enough to freeze carbon dioxide (around -130C or -200F). Nevertheless, gullies with very sharp, deep, v-shaped channels are seen on the pit walls. Based upon the locations of the tops of the channels on the slope shown here, the inferred site of liquid seepage is located at a layer in the pit wall about 1/3 of the way down from the top of the MOC image. The channels start wide and taper downslope. The area above the channels is layered and has been eroded by mass movement dry avalanching of debris--to form a pattern of chutes and ridges on the upper slope of the pit wall. The top layer appears to have many boulders in it (each about the size of a small house), these boulders are left behind on the upper slopes of the pit wall as debris is removed.

  14. Low-temperature synthesis of allyl dimethylamine by selective heating under microwave irradiation used for water treatment

    NASA Astrophysics Data System (ADS)

    Tian, Binghui; Luan, Zhaokun; Li, Mingming

    2005-08-01

    Low-temperature synthesis of allyl dimethylamine (ADA) by selective heating under microwave irradiation (MI) used for water treatment is investigated. The effect of MI, ultrasound irradiation (UI) and conventional heating on yield of ADA, reaction time and the flocculation efficiency of polydiallyl dimethylammunion chloride (PDADMAC) prepared form ADA were studied. The results show that by selective heating at low temperature, MI not only increases yield of ADA and reduces reaction time, but also greatly enhances the flocculation efficiency of PDADMAC.

  15. Development of an ionic liquid based dispersive liquid-liquid microextraction method for the analysis of polycyclic aromatic hydrocarbons in water samples.

    PubMed

    Pena, M Teresa; Casais, M Carmen; Mejuto, M Carmen; Cela, Rafael

    2009-09-04

    A simple, rapid and efficient method, ionic liquid based dispersive liquid-liquid microextraction (IL-DLLME), has been developed for the first time for the determination of 18 polycyclic aromatic hydrocarbons (PAHs) in water samples. The chemical affinity between the ionic liquid (1-octyl-3-methylimidazolium hexafluorophosphate) and the analytes permits the extraction of the PAHs from the sample matrix also allowing their preconcentration. Thus, this technique combines extraction and concentration of the analytes into one step and avoids using toxic chlorinated solvents. The factors affecting the extraction efficiency, such as the type and volume of ionic liquid, type and volume of disperser solvent, extraction time, dispersion stage, centrifuging time and ionic strength, were optimised. Analysis of extracts was performed by high performance liquid chromatography (HPLC) coupled with fluorescence detection (Flu). The optimised method exhibited a good precision level with relative standard deviation values between 1.2% and 5.7%. Quantification limits obtained for all of these considered compounds (between 0.1 and 7 ng L(-1)) were well below the limits recommended in the EU. The extraction yields for the different compounds obtained by IL-DLLME, ranged from 90.3% to 103.8%. Furthermore, high enrichment factors (301-346) were also achieved. The extraction efficiency of the optimised method is compared with that achieved by liquid-liquid extraction. Finally, the proposed method was successfully applied to the analysis of PAHs in real water samples (tap, bottled, fountain, well, river, rainwater, treated and raw wastewater).

  16. Vacuum ultraviolet light production by nuclear irradiation of liquid and gaseous xenon

    NASA Technical Reports Server (NTRS)

    Baldwin, G. C.

    1981-01-01

    Recent Los Alamos investigations suggest that a liquefied noble element may be the long-sought medium for a nuclear-excited laser or flashlamp. Research is needed to confirm this finding and to provide a basis for design and application studies. Quantitative and qualitative information are needed on the nature and behavior of the excited species, the effects of impurities and additives in the liquid phase under nuclear excitation, and the existence and magnitudes of nonlinear effects. Questions that need to be addressed and the most appropriate types of facilities for this task are identified.

  17. Ion irradiation in liquid of {mu}m{sup 3} region for cell surgery

    SciTech Connect

    Iwai, Yoshio; Ikeda, Tokihiro; Kojima, Takao M.; Yamazaki, Yasunori; Maeshima, Kazuhiro; Imamoto, Naoko; Kobayashi, Tomohiro; Nebiki, Takuya; Narusawa, Tadashi; Pokhil, Grigory P.

    2008-01-14

    We present here a cell surgery scheme involving selective inactivation or disruption of cellular structures. Energetic ions are injected into a cell through a tapered glass capillary like a microinjection method. A slight but essential difference from microinjection is that a thin window is prepared at the outlet so that no liquid material can flow in or back through the outlet while still allowing energetic ions to penetrate into the cell. An {approx}MeV He ion beam from such a capillary having 10 {mu}m outlet diameter inactivated a selected volume ({approx}{mu}m{sup 3}) of fluorescent molecules located in a HeLa cell nucleus.

  18. Effects of water in film boiling over liquid metal melts

    SciTech Connect

    Greene, G.A.; Finfrock, C.; Burson, S.B.

    1986-01-01

    Liquid-liquid boiling experiments have been performed with H/sub 2/O and liquid metal melts in the 100-series test matrix (Runs 121, 126, 127) and the VE test matrix. Some of the pre-explosion unstable film boiling data as well as observations from the explosive series have been previously reported.

  19. Rapid identification of γ-irradiated food by direct solvent extraction and liquid chromatography-tandem mass spectrometric analysis of 2-dodecylcyclobutanone: application in surveillance of irradiated food.

    PubMed

    Chan, Wan; Ye, Yuran; Leung, Elvis M K

    2014-10-15

    2-Dodecylcyclobutanone (2-DCB) is one of the major 2-alkylcyclobutanones (2-ACBs) that are uniquely formed when triglycerides are exposed to ionizing radiation and is being widely used as marker signature for identifying irradiated food. Current methods for 2-DCB extraction are either time-/solvent-consuming or involve the use of expensive extraction instruments. We have developed in this study an efficient extraction method for extracting 2-DCB from γ-irradiated food by direct extraction using acetonitrile. In comparison with the European standard method for irradiated food identification, our method reduced the per sample organic solvent consumption from 450 to 30mL per sample and shortened sample processing time from 8h to 30min. The assay combining direct acetonitrile extraction, precolumn derivatization with hydroxylamine, and LC-MS/MS analysis was validated with irradiated chicken as positive control, and applied in surveillance of irradiated food in Hong Kong. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Porous SiC nanowire arrays as stable photocatalyst for water splitting under UV irradiation

    SciTech Connect

    Liu, Hailong; She, Guangwei; Mu, Lixuan; Shi, Wensheng

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer Arrays of porous SiC nanowires prepared by a facile in situ carbonizing method. Black-Right-Pointing-Pointer Utilizing the SiC nanowire arrays as photocatalysis for water splitting. Black-Right-Pointing-Pointer Excellent photocatalytic performance under the UV irradiation. Black-Right-Pointing-Pointer Very high stability of the SiC nanowire photocatalyst. -- Abstract: In this study, we report the fabrication and photocatalytic properties of the oriented arrays of SiC nanowires on the Si substrate. The SiC nanowire arrays were prepared by carbonizing the Si nanowire arrays with the graphite powder at 1250 Degree-Sign C. The as-prepared SiC nanowires are highly porous, which endows them with a high surface-to-volume ratio. Considering the large surface areas and the high stability, the porous SiC nanowire arrays were used as photocatalyst for water splitting under UV irradiation. It was found that such porous SiC structure exhibited an enhanced and extremely stable photocatalytic performance.

  1. Angle-resolved photoemission spectroscopy of liquid water at 29.5 eV

    PubMed Central

    Nishitani, Junichi; West, Christopher W.; Suzuki, Toshinori

    2017-01-01

    Angle-resolved photoemission spectroscopy of liquid water was performed using extreme ultraviolet radiation at 29.5 eV and a time-of-flight photoelectron spectrometer. SiC/Mg coated mirrors were employed to select the single-order 19th harmonic from laser high harmonics, which provided a constant photon flux for different laser polarizations. The instrument was tested by measuring photoemission anisotropy for rare gases and water molecules and applied to a microjet of an aqueous NaI solution. The solute concentration was adjusted to eliminate an electric field gradient around the microjet. The observed photoelectron spectra were analyzed considering contributions from liquid water, water vapor, and an isotropic background. The anisotropy parameters of the valence bands (1b1, 3a1, and 1b2) of liquid water are considerably smaller than those of gaseous water, which is primarily attributed to electron scattering in liquid water. PMID:28405592

  2. Technical specification: Mixed-oxide pellets for the light-water reactor irradiation demonstration test

    SciTech Connect

    Cowell, B.S.

    1997-06-01

    This technical specification is a Level 2 Document as defined in the Fissile Materials Disposition Program Light-Water Reactor Mixed-oxide Fuel Irradiation Test Project Plan. It is patterned after the pellet specification that was prepared by Atomic Energy of Canada, Limited, for use by Los Alamos National Laboratory in fabrication of the test fuel for the Parallex Project, adjusted as necessary to reflect the differences between the Canadian uranium-deuterium reactor and light-water reactor fuels. This specification and the associated engineering drawing are to be utilized only for preparation of test fuel as outlined in the accompanying Request for Quotation and for additional testing as directed by Oak Ridge National Laboratory or the Department of Energy.

  3. Formation of high spatial frequency ripples in stainless steel irradiated by femtosecond laser pulses in water

    NASA Astrophysics Data System (ADS)

    Huo, Yanyan; Jia, Tianqing; Feng, Donghai; Zhang, Shian; Liu, Jukun; Pan, Jia; Zhou, Kan; Sun, Zhenrong

    2013-05-01

    We report the formation of high spatial frequency ripples (HSFRs) in stainless steel irradiated by 50 fs, 800 nm, 1 kHz femtosecond laser pulses in water. The period of the HSFRs, Λ, is less than 0.2λ, where λ is the laser wavelength. We further conduct theoretical calculations to study the ultrafast dynamics, and find that double splitting of the low spatial frequency ripples (LSFRs, Λ > 0.45λ) plays a decisive role in the formation of HSFRs. Similar experiments are conducted in copper, however, no splitting of LSFRs is observed. The different experimental results on stainless steel and copper conducted in water and in air are also discussed.

  4. Bacteria and fungi inactivation by photocatalysis under UVA irradiation: liquid and gas phase.

    PubMed

    Rodrigues-Silva, Caio; Miranda, Sandra M; Lopes, Filipe V S; Silva, Mário; Dezotti, Márcia; Silva, Adrián M T; Faria, Joaquim L; Boaventura, Rui A R; Vilar, Vítor J P; Pinto, Eugénia

    2016-06-29

    In the last decade, environmental risks associated with wastewater treatment plants (WWTPs) have become a concern in the scientific community due to the absence of specific legislation governing the occupational exposure limits (OEL) for microorganisms present in indoor air. Thus, it is necessary to develop techniques to effectively inactivate microorganisms present in the air of WWTPs facilities. In the present work, ultraviolet light A radiation was used as inactivation tool. The microbial population was not visibly reduced in the bioaerosol by ultraviolet light A (UVA) photolysis. The UVA photocatalytic process for the inactivation of microorganisms (bacteria and fungi, ATCC strains and isolates from indoor air samples of a WWTP) using titanium dioxide (TiO2 P25) and zinc oxide (ZnO) was tested in both liquid-phase and airborne conditions. In the slurry conditions at liquid phase, P25 showed a better performance in inactivation. For this reason, gas-phase assays were performed in a tubular photoreactor packed with cellulose acetate monolithic structures coated with P25. The survival rate of microorganisms under study decreased with the catalyst load and the UVA exposure time. Inactivation of fungi was slower than resistant bacteria, followed by Gram-positive bacteria and Gram-negative bacteria. Graphical abstract Inactivation of fungi and bacteria in gas phase by photocatalitic process performed in a tubular photoreactor packed with cellulose acetate monolith structures coated with TiO2.

  5. Automated dynamic liquid-liquid-liquid microextraction followed by high-performance liquid chromatography-ultraviolet detection for the determination of phenoxy acid herbicides in environmental waters.

    PubMed

    Wu, Jingming; Ee, Kim Huey; Lee, Hian Kee

    2005-08-05

    Automated dynamic liquid-liquid-liquid microextraction (D-LLLME) controlled by a programmable syringe pump and combined with HPLC-UV was investigated for the extraction and determination of 5 phenoxy acid herbicides in aqueous samples. In the extraction procedure, the acceptor phase was repeatedly withdrawn into and discharged from the hollow fiber by the syringe pump. The repetitive movement of acceptor phase into and out of the hollow fiber channel facilitated the transfer of analytes into donor phase, from the organic phase held in the pore of the fiber. Parameters such as the organic solvent, concentrations of the donor and acceptor phases, plunger movement pattern, speed of agitation and ionic strength of donor phase were evaluated. Good linearity of analytes was achieved in the range of 0.5-500 ng/ml with coefficients of determination, r2 > 0.9994. Good repeatabilities of extraction performance were obtained with relative standard deviations lower than 7.5%. The method provided up-to 490-fold enrichment within 13 min. In addition, the limits of detection (LODs) ranged from 0.1 to 0.4 ng/mL (S/N = 3). D-LLLME was successfully applied for the analysis of phenoxy acid herbicides from real environmental water samples.

  6. Water quantitatively induces the mucoadhesion of liquid crystalline phases of glyceryl monooleate.

    PubMed

    Lee, J; Young, S A; Kellaway, I W

    2001-05-01

    The possible role of water in the mucoadhesion phenomenon exhibited by the liquid crystalline phases of glyceryl monooleate was investigated using an in-vitro tensile strength technique. The mucoadhesion of the liquid crystalline phases of glyceryl monooleate was found to occur following uptake of water. The mucoadhesive force of the cubic phase was consistent since it is not capable of taking up additional water. An increase in pre-load period greatly facilitated the mucoadhesion of glyceryl monooleate (0% w/w initial water content), suggesting that the mucoadhesion is dependent upon the extent of the dehydration of the substrate. A good linear relationship between initial water content of the liquid crystalline phases and mucoadhesive force led to the conclusion that the mucoadhesive force increased with decreasing initial water concentration. Rheological properties of the liquid crystalline phases were also studied to allow a correlation between physical changes and mucoadhesion of the liquid crystalline phases, revealing that higher water concentrations in the liquid crystalline phases led to a more ordered structure that showed less mucoadhesion. The results of this study indicated that the mucoadhesive force of the liquid crystalline phases of glyceryl monooleate is determined by the capability to take up water from a water-rich environment. It may, therefore, be advantageous to use the lamellar phase as a buccal drug carrier as opposed to the relatively less mucoadhesive cubic phase.

  7. Laboratory Analysis Of Water, Hydrocarbon And Ammonia Ice Mixtures Exposed To High-energy Electron Irradiation

    NASA Astrophysics Data System (ADS)

    Hand, Kevin P.; Carlson, R. W.; Tsapin, A. I.

    2006-09-01

    Irradiation of low temperature ices in the laboratory provides insight into processes that may be occurring on icy bodies in the solar system. Here we report on results from high-energy (10keV) electron irradiation of thin ice films at 1e-8 torr and 70-120K. Mixtures include water with CO2, C3H8, C3H6, C4H10 (butane and isobutane), C4H8,(1-butene and cis/trans-2-butene), and NH3. During irradiation of H2O + alkane films at 80K, CO2 and CH4 production is observed and both species are retained in the ice, possibly trapped in clathrates. The -CH3 infrared bands initially present are seen to decrease with increasing dose. Bands associated with -CH2- persist, indicating polymerization of the initial short-chain hydrocarbons. In alkenes a similar evolution toward polymerization is observed, however the first step appears to be the destruction of the C=C bond. Upon warming of the film, mass spectra data compliment the mid-infrared data and indicate the production of H2CO, however glycolic acid is not explicitly seen in the mass spectra. When warmed to 300K, residues remained for all irradiated films except that of the H2O + CO2 mixtures. Residues were analyzed with Matrix Assisted Laser Desorption/Ionization Mass Spectrometry (MALDI). Results show the production of large aliphatic, very refractory, hydrocarbons (with m/z up to 2500). Mid-infrared spectra of the residues indicate carbonyls and alcohols, likely due to polymerized aldehydes and carboxylic acids. Films of H2O + C3H8 + NH3 at 70K show the production of OCN- (cyanate ion), formamide, along with other possible amides and hydrocarbons. HPLC results indicate the production of racemic alanine. Finally, results of abiotic experiments are compared to results from the irradiation of bacterial spores in ice. The application to Europa and Enceladus is discussed.

  8. Equilibrium structural model of liquid water: Evidence from heat capacity, spectra, density, and other properties

    NASA Astrophysics Data System (ADS)

    Dougherty, Ralph C.; Howard, Louis N.

    1998-11-01

    Hydrogen bond strength depends on both temperature and pressure. The gradient for hydrogen bond strength with temperature, or pressure, depends upon the hydrogen bonded structure. These features create an intimate connection between quantum mechanics and thermodynamics in the structure of liquid water. The equilibrium structural model of liquid water developed from analysis of the heat capacity at constant pressure is complex. The model is based on the assumptions that: (i) the hydrogen bond length and molecular packing density of water both vary with temperature; (ii) the number of different geometries for hydrogen bonding is limited to a small set; (iii) water molecules that possess these hydrogen bonding geometries are in equilibrium with each other under static conditions; (iv) significant changes in the slope of the heat capacity, Cp, and to a lesser extent other properties of the liquid, reflect the onset of significant changes in the chemical structure of the liquid; (v) the partial molal enthalpies and entropies of the different water arrays generated from these building blocks differ from each other in their dependence upon temperature; and (vi) the structure of the liquid is a random structural network of the structural components. The equilibrium structural model for liquid water uses four structural components and the assumptions listed above. At the extrapolated-homogeneous nucleation temperature, 221 K, a disordered hexagonal-diamond lattice (tetrahedrally hydrogen bonded water clusters) is the structure of liquid water. At the homogeneous nucleation temperature, ˜238 K, liquid water is a mixture of disordered tetrahedral water arrays and pentagonal water arrays. The abundance of tetrahedral water structures at this temperature causes the system to self-nucleate. As the temperature increases to 266 K the proportion of disordered pentagonal water clusters in the equilibrium mixture increases. At 256 K, the temperature of the previously unrecognized

  9. Studies of liquid water by computer simulations. V. Equation of state of fluid water with Carravetta-Clementi potential

    NASA Astrophysics Data System (ADS)

    Kataoka, Yosuke

    1987-07-01

    The pressure of liquid water at normal density is obtained by molecular dynamics simulations based on four intermolecular potential functions derived from quantum chemical calculations of the water dimer; Matsuoka-Clementi-Yoshimine, Carravetta-Clementi, Clementi-Habitz, Yoon-Morokuma-Davidson. Among them, the Carravetta-Clementi potential gives the most reasonable temperature-dependence of pressure, although the absolute value is large compared with the experimental one. The fluid state is surveyed over a wide range of temperature and density with the Carravetta-Clementi potential. The equation of state of fluid water is determined by a least-square fitting of the calculated energies and pressures at 347 state points. The anomalous properties of liquid water observed experimentally are nonempirically reproduced on a semiquantitative level. The calculated equation of state of liquid water is consistent with the Speedy-Angell conjecture on the limit of stability of the liquid phase.

  10. Probing the interactions between ionic liquids and water: experimental and quantum chemical approach.

    PubMed

    Khan, Imran; Kurnia, Kiki A; Mutelet, Fabrice; Pinho, Simão P; Coutinho, João A P

    2014-02-20

    For an adequate choice or design of ionic liquids, the knowledge of their interaction with other solutes and solvents is an essential feature for predicting the reactivity and selectivity of systems involving these compounds. In this work, the activity coefficient of water in several imidazolium-based ionic liquids with the common cation 1-butyl-3-methylimidazolium was measured at 298.2 K. To contribute to a deeper insight into the interaction between ionic liquids and water, COSMO-RS was used to predict the activity coefficient of water in the studied ionic liquids along with the excess enthalpies. The results showed good agreement between experimental and predicted activity coefficient of water in ionic liquids and that the interaction of water and ionic liquids was strongly influenced by the hydrogen bonding of the anion with water. Accordingly, the intensity of interaction of the anions with water can be ranked as the following: [CF3SO3](-) < [SCN](-) < [TFA](-) < Br(-) < [TOS](-) < Cl(-) < [CH3SO3](-) [DMP](-) < [Ac](-). In addition, fluorination and aromatization of anions are shown to reduce their interaction with water. The effect of temperature on the activity coefficient of water at infinite dilution was measured by inverse gas chromatography and predicted by COSMO-RS. Further analysis based on COSMO-RS provided information on the nature of hydrogen bonding between water and anion as well as the possibility of anion-water complex formation.

  11. Detection of solar wind-produced water in irradiated rims on silicate minerals

    PubMed Central

    Bradley, John P.; Ishii, Hope A.; Gillis-Davis, Jeffrey J.; Ciston, James; Nielsen, Michael H.; Bechtel, Hans A.; Martin, Michael C.

    2014-01-01

    The solar wind (SW), composed of predominantly ∼1-keV H+ ions, produces amorphous rims up to ∼150 nm thick on the surfaces of minerals exposed in space. Silicates with amorphous rims are observed on interplanetary dust particles and on lunar and asteroid soil regolith grains. Implanted H+ may react with oxygen in the minerals to form trace amounts of hydroxyl (−OH) and/or water (H2O). Previous studies have detected hydroxyl in lunar soils, but its chemical state, physical location in the soils, and source(s) are debated. If −OH or H2O is generated in rims on silicate grains, there are important implications for the origins of water in the solar system and other astrophysical environments. By exploiting the high spatial resolution of transmission electron microscopy and valence electron energy-loss spectroscopy, we detect water sealed in vesicles within amorphous rims produced by SW irradiation of silicate mineral grains on the exterior surfaces of interplanetary dust particles. Our findings establish that water is a byproduct of SW space weathering. We conclude, on the basis of the pervasiveness of the SW and silicate materials, that the production of radiolytic SW water on airless bodies is a ubiquitous process throughout the solar system. PMID:24449869

  12. Photoproduction of carbonyl sulfide in south Pacific Ocean waters as a function of irradiation wavelength

    NASA Technical Reports Server (NTRS)

    Weiss, Peter S.; Andrews, Steven S.; Johnson, James E.; Zafiriou, Oliver C.

    1995-01-01

    Carbonly sulfide (OCS) photoproduction rates were measured at selected wavelengths of ultraviolet light between 297 and 405 nm in sea water samples from the southern Pacific Ocean. Near-surface and column production rate spectra for natural sunlit waters were calculated using sea-surface sunlight data measured near the austral summer solstice. These plots show that photoproduction rates are at a maximum at 313 nm in tropical waters and at 336 nm in Antarctic waters. Tropical surface and column rates were found to be 68 pM/day and 360 nmol/sq m/day, respectively, and Antarctic surface and column rates were found to be 101 pM/day and 620 nmol/sq m/day, respectively. A high degree of variability was observed between photoproduction rates from different ocean regions, with coastal rates being the highest, suggesting that natural environmental variability is an important factor. Photoproduction rates at 297 nm were found to be constant at individual locations with increasing irradiation time. Relative photoproduction rates from this work are compared to previously measured rates from coastal sea water.

  13. Detection of solar wind-produced water in irradiated rims on silicate minerals.

    PubMed

    Bradley, John P; Ishii, Hope A; Gillis-Davis, Jeffrey J; Ciston, James; Nielsen, Michael H; Bechtel, Hans A; Martin, Michael C

    2014-02-04

    The solar wind (SW), composed of predominantly ∼1-keV H(+) ions, produces amorphous rims up to ∼150 nm thick on the surfaces of minerals exposed in space. Silicates with amorphous rims are observed on interplanetary dust particles and on lunar and asteroid soil regolith grains. Implanted H(+) may react with oxygen in the minerals to form trace amounts of hydroxyl (-OH) and/or water (H2O). Previous studies have detected hydroxyl in lunar soils, but its chemical state, physical location in the soils, and source(s) are debated. If -OH or H2O is generated in rims on silicate grains, there are important implications for the origins of water in the solar system and other astrophysical environments. By exploiting the high spatial resolution of transmission electron microscopy and valence electron energy-loss spectroscopy, we detect water sealed in vesicles within amorphous rims produced by SW irradiation of silicate mineral grains on the exterior surfaces of interplanetary dust particles. Our findings establish that water is a byproduct of SW space weathering. We conclude, on the basis of the pervasiveness of the SW and silicate materials, that the production of radiolytic SW water on airless bodies is a ubiquitous process throughout the solar system.

  14. Hydrophobic zeolites for biofuel upgrading reactions at the liquid-liquid interface in water/oil emulsions.

    PubMed

    Zapata, Paula A; Faria, Jimmy; Ruiz, M Pilar; Jentoft, Rolf E; Resasco, Daniel E

    2012-05-23

    HY zeolites hydrophobized by functionalization with organosilanes are much more stable in hot liquid water than the corresponding untreated zeolites. Silylation of the zeolite increases hydrophobicity without significantly reducing the density of acid sites. This hydrophobization with organosilanes makes the zeolites able to stabilize water/oil emulsions and catalyze reactions of importance in biofuel upgrading, i.e., alcohol dehydration and alkylation of m-cresol and 2-propanol in the liquid phase, at high temperatures. While at 200 °C the crystalline structure of an untreated HY zeolite collapses in a few hours in contact with a liquid medium, the functionalized hydrophobic zeolites keep their structure practically unaltered. Detailed XRD, SEM, HRTEM, and BET analyses indicate that even after reaction under severe conditions, the hydrophobic zeolites retain their crystallinity, surface area, microporosity, and acid density. It is proposed that by preferentially anchoring hydrophobic functionalities on the external surface, the direct contact of bulk liquid water and the zeolite is hindered, thus preventing the collapse of the framework during the reaction in liquid hot water.

  15. Evaporation of Ethanol-Water Binary Mixture Sessile Liquid Marbles.

    PubMed

    Ooi, Chin Hong; Bormashenko, Edward; Nguyen, Anh V; Evans, Geoffrey M; Dao, Dzung V; Nguyen, Nam-Trung

    2016-06-21

    Liquid marble is a liquid droplet coated with particles. Recently, the evaporation process of a sessile liquid marble using geometric measurements has attracted great attention from the research community. However, the lack of gravimetric measurement limits further insights into the physical changes of a liquid marble during the evaporation process. Moreover, the evaporation process of a marble containing a liquid binary mixture has not been reported before. The present paper investigates the effective density and the effective surface tension of an evaporating liquid marble that contains aqueous ethanol at relatively low concentrations. The effective density of an evaporating liquid marble is determined from the concurrent measurement of instantaneous mass and volume. Density measurements combined with surface profile fitting provide the effective surface tension of the marble. We found that the density and surface tension of an evaporating marble are significantly affected by the particle coa