WorldWideScience

Sample records for water wetting properties

  1. On the influence of the intermolecular potential on the wetting properties of water on silica surfaces

    Science.gov (United States)

    Pafong, E.; Geske, J.; Drossel, B.

    2016-09-01

    We study the wetting properties of water on silica surfaces using molecular dynamics (MD) simulations. To describe the intermolecular interaction between water and silica atoms, two types of interaction potential models are used: the standard BródkA and Zerda (BZ) model and the Gulmen and Thompson (GT) model. We perform an in-depth analysis of the influence of the choice of the potential on the arrangement of the water molecules in partially filled pores and on top of silica slabs. We find that at moderate pore filling ratios, the GT silica surface is completely wetted by water molecules, which agrees well with experimental findings, while the commonly used BZ surface is less hydrophilic and is only partially wetted. We interpret our simulation results using an analytical calculation of the phase diagram of water in partially filled pores. Moreover, an evaluation of the contact angle of the water droplet on top of the silica slab reveals that the interaction becomes more hydrophilic with increasing slab thickness and saturates around 2.5-3 nm, in agreement with the experimentally found value. Our analysis also shows that the hydroaffinity of the surface is mainly determined by the electrostatic interaction, but the van der Waals interaction nevertheless is strong enough that it can turn a hydrophobic surface into a hydrophilic surface.

  2. Wetting Transition in Water

    Science.gov (United States)

    Friedman, S. R.; Khalil, M.; Taborek, P.

    2013-11-01

    Optical images were used to study the wetting behavior of water on graphite, sapphire, and quartz along the liquid vapor coexistence curve from room temperature to 300°C. Wetting transitions were identified by the temperature at which the contact angle decreased to zero and also by the disappearance of dropwise condensation. These two methods yielded consistent values for the wetting temperatures, which were 185°C, 234°C, and 271°C for water on quartz, sapphire, and graphite, respectively. We compare our results with the theoretical predictions based on a simplified model of the water-substrate potential and sharp interfaces.

  3. Wet water glass production plant

    Directory of Open Access Journals (Sweden)

    Stanković Mirjana S.

    2003-01-01

    Full Text Available The IGPC Engineering Department designed basic projects for a wet hydrate dissolution plant, using technology developed in the IGPC laboratories. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant of a capacity of 75,000 t/y was manufactured, at "Zeolite Mira", Mira (VE, Italy, in 1997. and 1998, increasing detergent zeolite production, from 50,000 to 100,000 t/y. Several goals were realized by designing a wet hydrate dissolution plant. The main goal was increasing the detergent zeolite production. The technological cycle of NaOH was closed, and no effluents emitted, and there is no pollution (except for the filter cake. The wet water glass production process is fully automatized, and the product has uniform quality. The production process can be controlled manually, which is necessary during start - up, and repairs. By installing additional process equipment (centrifugal pumps and heat exchangers technological bottlenecks were overcome, and by adjusting the operation of autoclaves, and water glass filters and also by optimizing the capacities of process equipment.

  4. Wetting properties of nanostructured surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ramos-Canut, S. [Laboratoire de Physique de la Matiere Condensee et Nanostructures (UMR CNRS 5586), Universite Claude Bernard Lyon 1, 69622 Villeurbanne Cedex (France)]. E-mail: ramos@lpmcn.univ-lyon1.fr

    2006-04-15

    Swift heavy ion irradiation is a powerful tool to tailor surfaces under controlled conditions at a nanometric scale. The growing importance of nanostructured surfaces for a wide variety of applications and fundamental investigations is now well established. In this paper I will mainly discuss the interest of such surfaces for investigations concerning solid-liquid interfaces. The role played by topographical defects on wetting properties of solid surfaces, and both the dissipative and the confinement effects on the interface will be demonstrated by simple examples.

  5. Impact of wet season river flood discharge on phytoplankton absorption properties in the southern Great Barrier Reef region coastal waters

    Science.gov (United States)

    Cherukuru, Nagur; Brando, Vittorio E.; Blondeau-Patissier, David; Ford, Phillip W.; Clementson, Lesley A.; Robson, Barbara J.

    2017-09-01

    Light absorption due to particulate and dissolved material plays an important role in controlling the underwater light environment and the above water reflectance signature. Thorough understanding of absorption properties and their variability is important to estimate light propagation in the water column. However, knowledge of light absorption properties in flood impacted coastal waters is limited. To address this knowledge gap we investigated a bio-optical dataset collected during a flood (2008) in the southern Great Barrier Reef (GBR) region coastal waters. Results presented here show strong impact of river flood discharges on water column stratification, distribution of suspended substances and light absorption properties in the study area. Bio-optical analysis showed phytoplankton absorption efficiency to reduce in response to increased coloured dissolved organic matter presence in flood impacted coastal waters. Biogeophysical property ranges, relationships and parametrisation presented here will help model realistic underwater light environment and optical signature in flood impacted coastal waters.

  6. Effects of the water level hydrated in NMMO on the physical properties of cellulose fiber in dry jet-wet spinning

    Energy Technology Data Exchange (ETDEWEB)

    Kim, D.B.; Lee, W.S.; Kim, B.C.; Jo, S.M.; Park, J.S. [Korea Institute of Science and Technology, Seoul (Korea, Republic of); Lee, Y.M. [Hanyang University, Seoul (Korea, Republic of)

    1998-03-01

    The effects of the amount of water hydrated in N-methylmorpholine N-oxide (NMMO) in dry jet-wet spinning of cellulose was investigated in terms of rheological properties of the spinning dope and the physical properties of the fiber. At the identical polymer concentration of 12 wt%, the solution of cellulose in 90.4 wt% NMMO gave higher viscosity and higher storage modulus (G`) than that in 86.7 wt% NMMO, which was more noticeable at 110 {sup o} C than at 12 {sup o} C. Decrease in the hydrated water level or increase in the air-gap or spin draw ratio increased such physical properties of the fiber as birefringence, initial modulus and tensile strength. The tensile fractured morphology revealed that the fiber from NMMO containing less water gave more fibrils resulting from higher orientation. Further, it produced thicker and longer fibrils when treated with an ultrasonic generator.

  7. Analysis on Wetting Deformation Properties of Silty Clay

    Directory of Open Access Journals (Sweden)

    Xinrong Liu

    2014-06-01

    Full Text Available Changes in water level that cause deformation and stability problems often occur in foundation pit engineering. Water damage is one of the main problems that will lead to disasters in foundation pit engineering. Research findings with regard to properties of wetting deformation due to water damage can be applied not only in foundation pit engineering, slope engineering, hydraulic engineering, and mining engineering but also in related issues in the field of theoretical research and practice. In this study, the characteristics of silty clay deformation after wetting are examined from the perspective of the effect of wetting on the side wall of foundation pit, and wetting experiments on silty clay of a selected area’s stratum located in Chongqing Municipality are conducted under different confining pressures and stress levels through a multi-function triaxial apparatus. Then, laws of silty clay wetting deformation are obtained, and the relationship between wetting stress level and wetting deformation amount is also figured out. The study reveals that the maximum values of wetting deformation under different confining pressures have appear at a particular stress level; therefore, the related measures should be taken to avoid this deformation in the process of construction.

  8. Quantitative structure-property relationship modeling of water-to-wet butyl acetate partition coefficient of 76 organic solutes using multiple linear regression and artificial neural network.

    Science.gov (United States)

    Dashtbozorgi, Zahra; Golmohammadi, Hassan

    2010-12-01

    The main aim of this study was the development of a quantitative structure-property relationship method using an artificial neural network (ANN) for predicting the water-to-wet butyl acetate partition coefficients of organic solutes. As a first step, a genetic algorithm-multiple linear regression model was developed; the descriptors appearing in this model were considered as inputs for the ANN. These descriptors are principal moment of inertia C (I(C)), area-weighted surface charge of hydrogen-bonding donor atoms (HACA-2), Kier and Hall index (order 2) ((2)χ), Balaban index (J), minimum bond order of a C atom (P(C)) and relative negative-charged SA (RNCS). Then a 6-4-1 neural network was generated for the prediction of water-to-wet butyl acetate partition coefficients of 76 organic solutes. By comparing the results obtained from multiple linear regression and ANN models, it can be seen that statistical parameters (Fisher ratio, correlation coefficient and standard error) of the ANN model are better than that regression model, which indicates that nonlinear model can simulate the relationship between the structural descriptors and the partition coefficients of the investigated molecules more accurately.

  9. Mechanical Properties of Sheared Wet Granular Piles

    Science.gov (United States)

    Seemann, Ralf; Schaber, Marc; Karmakar, Somnath; Hippler, Anna-Lena; Scheel, Mario; di Michiel, Marco; Brinkmann, Martin

    2015-03-01

    The mechanical properties of dry and wet granulates are explored when being sheared with a parabolic profile at constant shear volume. The dissipated energy increase linearly with external pressure both for a wet and a dry granulate. However, the dissipated energy for wet a granulate has a finite value for the limiting case of vanishing external pressure and increases slower with external pressure compared to the dry granulate. Using a down sized version of the shear cell the reorganization of a granulate and liquid is additionally imaged in real time using x-ray micro-tomography. With the insight from x-ray tomography the contribution of the breaking capillary bridges to the dissipated energy can be analyzed. We could also shed light on the influence of dilatation effects on the dissipated energy upon inverting the shear direction.

  10. Wetting properties of molecularly rough surfaces

    Science.gov (United States)

    Svoboda, Martin; Malijevský, Alexandr; Lísal, Martin

    2015-09-01

    We employ molecular dynamics simulations to study the wettability of nanoscale rough surfaces in systems governed by Lennard-Jones (LJ) interactions. We consider both smooth and molecularly rough planar surfaces. Solid substrates are modeled as a static collection of LJ particles arranged in a face-centered cubic lattice with the (100) surface exposed to the LJ fluid. Molecularly rough solid surfaces are prepared by removing several strips of LJ atoms from the external layers of the substrate, i.e., forming parallel nanogrooves on the surface. We vary the solid-fluid interactions to investigate strongly and weakly wettable surfaces. We determine the wetting properties by measuring the equilibrium droplet profiles that are in turn used to evaluate the contact angles. Macroscopic arguments, such as those leading to Wenzel's law, suggest that surface roughness always amplifies the wetting properties of a lyophilic surface. However, our results indicate the opposite effect from roughness for microscopically corrugated surfaces, i.e., surface roughness deteriorates the substrate wettability. Adding the roughness to a strongly wettable surface shrinks the surface area wet with the liquid, and it either increases or only marginally affects the contact angle, depending on the degree of liquid adsorption into the nanogrooves. For a weakly wettable surface, the roughness changes the surface character from lyophilic to lyophobic due to a weakening of the solid-fluid interactions by the presence of the nanogrooves and the weaker adsorption of the liquid into the nanogrooves.

  11. Structural and wetting properties of fuel cell components

    Science.gov (United States)

    Volfkovich, Yu. M.; Sosenkin, V. E.; Bagotsky, V. S.

    The operation of proton exchange membrane (PEMFC) and direct methanol fuel cells (DMFC) is connected with the flow of different gaseous and liquid components in the cell's membrane-electrode assembly (MEA). The structural and wetting properties of different components of the MEA influence the rate and direction of these flows and hence the fuel cell's efficiency. For a better understanding of the mechanism of all processes influencing the fuel cell efficiency, for a mathematical modelling of these processes, and for a possibility of their optimization, a detailed knowledge of the geometrical structure and wetting properties of all MEA components is necessary. This review describes the results of such investigations performed mainly by using the method of standard contact porosimetry (MSCP). This method gives the possibility to receive information on multicomponent porous and powdered materials hitherto not accessible, viz. their wetting and swelling properties, pore corrugation, and also isotherms of capillary pressure and bond energy. Measurements of MEA components by this method can be performed under exactly the same conditions (temperature, compression degree, contact with water, etc.) as those existing in real fuel cells.

  12. Wick wetting for water condensation systems

    Energy Technology Data Exchange (ETDEWEB)

    Hering, Susanne Vera; Spielman, Steven Russel; Lewis, Gregory Stephen; Kreisberg, Nathan Michael

    2017-04-04

    A system and method for particle enlargement with continuously wetted wicks includes a container into which a flow of particle-laden air is introduced in a laminar manner through an inlet and to an outlet. The container has a first section, a second section and a third section though which the particle-laden air flows between the inlet and the outlet. The temperature of the second section is warmer than that of the first section at the inlet and the third section at the outlet. In one embodiment, a continuous wick spanning an interior wall of the first second, second section and third section, said wick being capable of internally transporting liquid water along its length is provided.

  13. Soil physical properties changed induced by dry-wet cycles in the water-level fluctuation zone of Three Gorges Reservoir region, China

    Science.gov (United States)

    Cui, Junfang; Tang, Xiangyu; Zhang, Wei

    2017-04-01

    In southwest China, a grand hydraulic engineering called Three Gorges Dam (TGD) was completed and under full power run since 2009, making a total area of 349 km2 along Yangtze River exposing the dry-wet cycles by its impounding of water step by step from the elevations of 135 m in summer season to 175 m in winter season at each year. As populated area, the environmental issues aroused by the TGR have centered on water quality, biodiversity, sedimentation, downstream riverbed erosion and pollutants (both heavy metals and organic pollutants) transportation. All these are regulated or affected by soil structure and pore network, directly or indirectly. Thus, the study of soil physical quality changed induced by these seasonal dry-wet cycles is crucial. The objective of this study is: (1) to describe soil structural status in WLF zone of TGR by combination of laboratory measures and visual evaluation method; (2) to describe the pore system in this zone by both SWRC and CT images; and (3) to address the changes of soil physical quality changed by seasonal dry-wet cycles. Our results showed a deterioration of soil structure (indicated by a high Sq score in VESS) and soil aggregate stability (indicated by low MWD and the mass fractal dimension Dm) in lower land of TGR. The data from both soil water retention curve and micro-CT image demonstrates a going -worse of soil physical quality by decreasing of soil pore number and porosity as well as a shift of drainable micro-pores (0.1 < r < 125 µm) to non-drainable micro-pores (r < 0.1 µm) in the lower land of TGR.

  14. Wetting dynamics of a water nanodrop on graphene.

    Science.gov (United States)

    Andrews, Joseph Eugene; Sinha, Shayandev; Chung, Peter W; Das, Siddhartha

    2016-09-14

    Water-graphene wetting interactions are central to several applications such as desalination, water filtration, electricity generation, biochemical sensing, fabrication of fuel cells, and many more. While substantial attention has been devoted to probe the wetting statics of a water drop on graphene, unraveling the possible wetting translucency nature of graphene, very little research has been done on the dynamics of wetting of water drops on graphene-coated solids or free-standing graphene layers. In this paper, we employ molecular dynamics (MD) simulations to study the contact and the spreading of a water nanodrop, quantifying its wetting dynamics, on supported and free-standing graphene. We demonstrate that nanoscale water drops establish contact with graphene by forming patches on graphene, and this patch formation is hastened for graphene layer(s) supported on hydrophilic solids. More importantly, our results demonstrate that the nanodrop spreading dynamics, regardless of the number of graphene layers or the nature of the underlying solid, obey the half-power law, i.e., r∼t(1/2) (where r is the wetting contact radius and t is the spreading time) for the entire timespan of spreading except towards the very end of the spreading lifetime when the spreading stops. Such a spreading behavior is exactly analogous to the spreading dynamics of nanodroplets for standard solids - this is in sharp contrast to the wetting statics of graphene where the wetting translucency effect makes graphene different from other standard solids.

  15. On the gasification of wet biomass in supercritical water : over de vergassing van natte biomassa in superkritiek water

    NARCIS (Netherlands)

    Withag, J.A.M.

    2013-01-01

    Supercritical water gasification (SCWG) is a challenging thermo-chemical conversion route for wet biomass and waste streams into hydrogen and/or methane. At temperatures and pressures above the critical point the physical properties of water differ strongly from liquid water or steam. Because of the

  16. Hydrophobic Surfaces: Topography Effects on Wetting by Supercooled Water and Freezing Delay

    DEFF Research Database (Denmark)

    Heydari, Golrokh; Thormann, Esben; Järn, Mikael

    2013-01-01

    Hydrophobicity, and in particular superhydrophobicity, has been extensively considered to promote ice-phobicity. Dynamic contact angle measurements above 0 °C have been widely used to evaluate the water repellency. However, it is the wetting properties of supercooled water at subzero temperatures...

  17. Wetting of doped carbon nanotubes by water droplets

    DEFF Research Database (Denmark)

    Kotsalis, E. M.; Demosthenous, E.; Walther, Jens Honore

    2005-01-01

    We study the wetting of doped single- and multi-walled carbon nanotubes by water droplets using molecular dynamics simulations. Chemisorbed hydrogen is considered as a model of surface impurities. We study systems with varying densities of surface impurities and we observe increased wetting......, as compared to the pristine nanotube case, attributed to the surface dipole moment that changes the orientation of the interfacial water. We demonstrate that the nature of the impurity is important as here hydrogen induces the formation of an extended hydrogen bond network between the water molecules...

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  19. Subcritical water extraction of lipids from wet algal biomass

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Shuguang; Reddy, Harvind K.; Schaub, Tanner; Holguin, Francisco Omar

    2016-05-03

    Methods of lipid extraction from biomass, in particular wet algae, through conventionally heated subcritical water, and microwave-assisted subcritical water. In one embodiment, fatty acid methyl esters from solids in a polar phase are further extracted to increase biofuel production.

  20. Subcritical water extraction of lipids from wet algal biomass

    Science.gov (United States)

    Deng, Shuguang; Reddy, Harvind K.; Schaub, Tanner; Holguin, Francisco Omar

    2016-05-03

    Methods of lipid extraction from biomass, in particular wet algae, through conventionally heated subcritical water, and microwave-assisted subcritical water. In one embodiment, fatty acid methyl esters from solids in a polar phase are further extracted to increase biofuel production.

  1. Effect of wet grinding on structural properties of ball clay

    Science.gov (United States)

    Purohit, A.; Hameed, A.; Chander, S.; Nehra, S. P.; Singh, P.; Dhaka, M. S.

    2015-05-01

    In this paper, the effect of wet grinding on structural properties of ball clay is undertaken. The wet grinding treatment was performed employing ball and vibro mills for different time spells of 2, 4, 8 and 16 hours. The structural properties were carried out using X-ray diffraction (XRD). The structure of ground samples is found to be simple cubic. The crystallographic parameters are calculated and slight change in lattice constant, inter planner spacing and particle size is observed with grinding treatment. The results are in agreement with the available literature.

  2. Mechanical properties of wet granular materials

    Energy Technology Data Exchange (ETDEWEB)

    Fournier, Z; Geromichalos, D; Herminghaus, S; Kohonen, M M; Mugele, F; Scheel, M; Schulz, M; Schulz, B; Schier, Ch; Seemann, R; Skudelny, A

    2005-03-09

    We elaborate on the impact of liquids upon the mechanical properties of granular materials. We find that most of the experimental and simulation results may be accounted for by a simple model assuming frictionless, spherical grains, with a hysteretic attractive interaction between neighbouring grains due to capillary forces.

  3. Critical wetting of n-alkanes on water; Mouillage critique des alcanes sur l`eau

    Energy Technology Data Exchange (ETDEWEB)

    Ragil, K.

    1996-10-18

    This study concerns the wetting properties of n-alkanes on water under thermodynamic equilibrium conditions, a problem that is interesting for the petroleum industry as well as for the fundamental understanding of wetting phenomena. An experimental study using ellipsometry reveals that pentane on water undergoes a continuous or critical wetting transition at a temperature equal to 53.1 deg. C. This is the first experimental observation of such a transition, confirming theoretical predictions made on this subject over ten years. This transition is characterized by a continuous and reversible evolution of the thickness of the film of pentane with temperature from a thick (but finite film) to a macroscopic film. The critical wetting transition occurs when the Hamaker constant of the system, which gives the net interaction between the two interfaces bounding the wetting layer of pentane in terms of the van der Waals forces, changes sign. A theoretical approach based on the Cahn-Landau theory, which takes into account long range forces (van der Waals forces), enables us to explain the mechanism of the critical wetting transition and to show that a first-order wetting transition should precede it. Because of their similar dispersive properties, linear alkanes could all be able to show such a succession of transitions. An ellipsometry study performed on a brine/hexane/vapor system confirms that a discontinuous transition from a thin microscopic film to a thick but finite adsorbed film takes place. THis study demonstrates that the wetting of alkanes on water is determined by subtle interplay between short range and long range forces, which can lead to an intermediary state between partial and complete wetting. (author)

  4. The influence of the hydrophobic agent, catalyst, solvent and water content on the wetting properties of the silica films prepared by one-step sol–gel method

    Energy Technology Data Exchange (ETDEWEB)

    Ramezani, Maedeh, E-mail: m.ramezani@merc.ac.ir [Division of Nanotechnology and Advanced Materials, Materials and Energy Research Center, P.O. Box 31787-316, Karaj (Iran, Islamic Republic of); Vaezi, Mohammad Reza [Division of Nanotechnology and Advanced Materials, Materials and Energy Research Center, P.O. Box 31787-316, Karaj (Iran, Islamic Republic of); Kazemzadeh, Asghar [Division of Semiconductors, Materials and Energy Research Center, P.O. Box 31787-316, Karaj (Iran, Islamic Republic of)

    2015-01-30

    Graphical abstract: - Highlights: • Transparent, hydrophobic, uniform silica film by sol–gel co-precursor process. • Preparation of silica coatings from ETES and Iso-OTMS in different molar ratios. • Decreasing in hydrophobicity of the films with increasing in Iso-TMS molar ratio. • By changing the molar ratio of component, different size of particles was obtained. - Abstract: In this paper, we used one-step sol–gel process to prepare the hydrophobic silica films on the glass substrate from the ethyltriethoxysilane (ETES) as a precursor and iso-octyltrimethoxysilane (Iso-OTMS) as a hydrophobic agent. In order to study the effect of the hydrophobic agent on the water repellent properties of the silica films, the alcosol was prepared by keeping constant the molar ratio of ETES:EtOH:H{sub 2}O at 1:36.2:6.3, with 6 M ammonium hydroxide and Iso-OTMS/ETES molar ratio varied from 0.2 to 1.4. Also, we investigated the influence of the other sol–gel reaction parameters, such as catalyst, solvent and water content and their effect on the morphology and hydrophobic properties of the silica films. The results revealed that by altering the molar ratio of NH{sub 4}OH, EtOH and H{sub 2}O, different sizes of silica nanoparticles from 41.24 to 86.16 nm were obtained. The silica films were characterized by atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) images, contact angle measurement (CA) and percentage of optical transmission.

  5. Universal wetting transition of an evaporating water droplet on superhydrophobic surfaces

    Science.gov (United States)

    Tsai, Peichun Amy; Bussonnière, Adrien; Bigdeli, Masoud; Chueh, Di-Yen; Liu, Qingxia; Chen, Peilin

    2016-11-01

    An evaporating water droplet on a superhydrophobic surface undergoes a wetting transition from a heterogeneous wetting (Cassie-Baxter) to homogeneous wetting (Wenzel) state. The critical transition is manifested by a sudden decrease of contact angle, when "Fakir" water drop permeates the minute hydrophobic cavities. This breakdown of superhydrophobicity would hinder various applications of self-cleaning, low-frictional, and potentially ice-phobic properties of superhydrophobic materials. In this work, we experimentally investigate such wetting transition using hydrophobic nanostructures. With a theoretical model, we find a universal criterion of the critical contact angle at the transition point. The prediction of critical contact angle, which solely depends on the geometrical parameters of the hydrophobic pillars, agree well with various data for both micro- and nano-structures.

  6. Physicochemical properties and combustion behavior of duckweed during wet torrefaction.

    Science.gov (United States)

    Zhang, Shuping; Chen, Tao; Li, Wan; Dong, Qing; Xiong, Yuanquan

    2016-10-01

    Wet torrefaction of duckweed was carried out in the temperature range of 130-250°C to evaluate the effects on physicochemical properties and combustion behavior. The physicochemical properties of duckweed samples were investigated by ultimate analysis, proximate analysis, FTIR, XRD and SEM techniques. It was found that wet torrefaction improved the fuel characteristics of duckweed samples resulting from the increase in fixed carbon content, HHVs and the decrease in nitrogen and sulfur content and atomic ratios of O/C and H/C. It can be seen from the results of FTIR, XRD and SEM analyses that the dehydration, decarboxylation, solid-solid conversion, and condensation polymerization reactions were underwent during wet torrefaction. In addition, the results of thermogravimetric analysis (TGA) in air indicated that wet torrefaction resulted in significant changes on combustion behavior and combustion kinetics parameters. Duckweed samples after wet torrefaction behaved more char-like and gave better combustion characteristics than raw sample. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Diffusion Monte Carlo ab initio calculations to study wetting properties of graphene

    Science.gov (United States)

    Wu, Yanbin; Zheng, Huihuo; Wagner, Lucas; Aluru, N. R.

    2013-11-01

    For applications of graphene in water, including for example desalination and DNA sequencing, it is critical to understand the wetting properties of graphene. In this work, we investigate the wetting properties using data from highly accurate diffusion quantum Monte Carlo (DMC) calculations, which treat electron correlation explicitly. Our DMC data show a strong graphene-water interaction, indicating graphene surface is more hydrophilic than previously believed. This has been recently confirmed by experiments [Li et al. Nat. Mater. 2013, doi:10.1038/nmat3709]. The unusually strong interaction can be attributed to weak bonding formed between graphene and water. Besides its inadequate description of dispersion interactions as commonly reported in the literature, density function theory (DFT) fails to describe the correct charge transfer, which leads to an underestimate of graphene-water binding energy. Our DMC calculations can provide insight to experimentalists seeking to understand water-graphene interfaces and to theorists improving DFT for weakly bound systems.

  8. An engineered anisotropic nanofilm with unidirectional wetting properties

    Science.gov (United States)

    Malvadkar, Niranjan A.; Hancock, Matthew J.; Sekeroglu, Koray; Dressick, Walter J.; Demirel, Melik C.

    2010-12-01

    Anisotropic textured surfaces allow water striders to walk on water, butterflies to shed water from their wings and plants to trap insects and pollen. Capturing these natural features in biomimetic surfaces is an active area of research. Here, we report an engineered nanofilm, composed of an array of poly(p-xylylene) nanorods, which demonstrates anisotropic wetting behaviour by means of a pin-release droplet ratchet mechanism. Droplet retention forces in the pin and release directions differ by up to 80μN, which is over ten times greater than the values reported for other engineered anisotropic surfaces. The nanofilm provides a microscale smooth surface on which to transport microlitre droplets, and is also relatively easy to synthesize by a bottom-up vapour-phase technique. An accompanying comprehensive model successfully describes the film's anisotropic wetting behaviour as a function of measurable film morphology parameters.

  9. WET TORREFACTION OF MISCANTHUS – CHARACTERIZATION OF HYDROCHARS IN VIEW OF HANDLING, STORAGE AND COMBUSTION PROPERTIES

    Directory of Open Access Journals (Sweden)

    Mateusz Wnukowski

    2015-06-01

    Full Text Available Properties of miscanthus hydrochars obtained through wet torrefaction were studied. The process was carried out in three different temperatures – 180, 200 and 220 °C and with four different ratios of water to biomass – 3:1, 6:1, 12:1 and 16:1. The obtained solid products were characterized with respect to their fuel properties. The best results were obtained for the temperature of 220 °C and showed a noticeable improvement in fuel properties – especially grindability and lowered ash content. The influence of water to biomass ratio was not so explicit and while high ratio showed an improvement in all mentioned properties, low ratio allowed to achieve the highest energy yield. The results obtained for miscanthus wet torrefaction and the literature data for dry torrefaction were compared.

  10. Universal wetting transition of an evaporating water droplet on hydrophobic micro- and nano-structures.

    Science.gov (United States)

    Bussonnière, Adrien; Bigdeli, Masoud B; Chueh, Di-Yen; Liu, Qingxia; Chen, Peilin; Tsai, Peichun Amy

    2017-02-07

    Water-repellent, rough surfaces have a remarkable and beneficial wetting property: when a water droplet comes in contact with a small fraction of the solid, both liquid-solid adhesion and hydrodynamic drag are reduced. As a prominent example from nature, the lotus leaf-comprised of a wax-like material with micro- and nano-scaled roughness-has recently inspired numerous syntheses of superhydrophobic substrates. Due to the diverse applications of superhydrophobicity, much research has been devoted to the fabrication and investigations of hydrophobic micro-structures using established micro-fabrication techniques. However, wetting transitions remain relatively little explored. During evaporation, a water droplet undergoes a wetting transition from a (low-frictional) partial to (adhesive) complete contact with the solid, destroying the superhydrophobicity and the self-cleaning properties of the slippery surface. Here, we experimentally examine the wetting transition of a drying droplet on hydrophobic nano-structures, a previously unexplored regime. In addition, using a theoretical analysis we found a universal criterion of this wetting transition that is characterized by a critical contact angle. Different from previous results showing different critical droplet sizes, our results show a universal, geometrically-dependent, critical contact angle, which agrees well with various data for both hydrophobic micro- and nano-structures.

  11. Wetting properties of fungi mycelium alter soil infiltration and soil water repellency in a γ-sterilized wettable and repellent soil.

    Science.gov (United States)

    Chau, Henry Wai; Goh, Yit Kheng; Vujanovic, Vladimir; Si, Bing Cheng

    2012-12-01

    Soil water repellency (SWR) has a drastic impact on soil quality resulting in reduced infiltration, increased runoff, increased leaching, reduced plant growth, and increased soil erosion. One of the causes of SWR is hydrophobic fungal structures and exudates that change the soil-water relationship. The objective of this study was to determine whether SWR and infiltration could be manipulated through inoculation with fungi. The effect of fungi on SWR was investigated through inoculation of three fungal strains (hydrophilic -Fusarium proliferatum, chrono-amphiphilic -Trichoderma harzianum, and hydrophobic -Alternaria sp.) on a water repellent soil (WR-soil) and a wettable soil (W-soil). The change in SWR and infiltration was assessed by the water repellency index and cumulative infiltration respectively. F. proliferatum decreased the SWR on WR-soil and slightly increased SWR in W-soil, while Alternaria sp. increased SWR in both the W-soil and the WR-soil. Conversely T. harzianum increased the SWR in the W-soil and decreased the SWR in the WR-soil. All strains showed a decrease in infiltration in W-soil, while only the F. proliferatum and T. harzianum strain showed improvement in infiltration in the WR-soil. The ability of fungi to alter the SWR and enmesh soil particles results in changes to the infiltration dynamics in soil. Copyright © 2012 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.

  12. Contact angles of wetting and water stability of soil structure

    Science.gov (United States)

    Kholodov, V. A.; Yaroslavtseva, N. V.; Yashin, M. A.; Frid, A. S.; Lazarev, V. I.; Tyugai, Z. N.; Milanovskiy, E. Yu.

    2015-06-01

    From the soddy-podzolic soils and typical chernozems of different texture and land use, dry 3-1 mm aggregates were isolated and sieved in water. As a result, water-stable aggregates and water-unstable particles composing dry 3-1 mm aggregates were obtained. These preparations were ground, and contact angles of wetting were determined by the static sessile drop method. The angles varied from 11° to 85°. In most cases, the values of the angles for the water-stable aggregates significantly exceeded those for the water-unstable components. In terms of carbon content in structural units, there was no correlation between these parameters. When analyzing the soil varieties separately, the significant positive correlation between the carbon content and contact angle of aggregates was revealed only for the loamy-clayey typical chernozem. Based on the multivariate analysis of variance, the value of contact wetting angle was shown to be determined by the structural units belonging to water-stable or water-unstable components of macroaggregates and by the land use type. In addition, along with these parameters, the texture has an indirect effect.

  13. Water Touch-and-Bounce from a Soft Viscoelastic Substrate: Wetting, Dewetting, and Rebound on Bitumen.

    Science.gov (United States)

    Lee, Jae Bong; Dos Santos, Salomé; Antonini, Carlo

    2016-08-16

    Understanding the interaction between liquids and deformable solid surfaces is a fascinating fundamental problem, in which interaction and coupling of capillary and viscoelastic effects, due to solid substrate deformation, give rise to complex wetting mechanisms. Here we investigated as a model case the behavior of water drops on two smooth bitumen substrates with different rheological properties, defined as hard and soft (with complex shear moduli in the order of 10(7) and 10(5) Pa, respectively, at 1 Hz), focusing both on wetting and on dewetting behavior. By means of classical quasi-static contact angle measurements and drop impact tests, we show that the water drop behavior can significantly change from the quasi-static to the dynamic regime on soft viscoelastic surfaces, with the transition being defined by the substrate rheological properties. As a result, we also show that on the hard substrate, where the elastic response is dominant under all investigated conditions, classical quasi-static contact angle measurements provide consistent results that can be used to predict the drop dynamic wetting behavior, such as drop deposition or rebound after impact, as typically observed for nondeformable substrates. Differently, on soft surfaces, the formation of wetting ridges did not allow to define uniquely the substrate intrinsic advancing and receding contact angles. In addition, despite showing a high adhesion to the soft surface in quasi-static measurements, the drop was surprisingly able to rebound and escape from the surface after impact, as it is typically observed for hydrophobic surfaces. These results highlight that measurements of wetting properties for viscoelastic substrates need to be critically used and that wetting behavior of a liquid on viscoelastic surfaces is a function of the characteristic time scales.

  14. Wet peroxide oxidation and catalytic wet oxidation of stripped sour water produced during oil shale refining.

    Science.gov (United States)

    Prasad, Jaidev; Tardio, James; Jani, Harit; Bhargava, Suresh K; Akolekar, Deepak B; Grocott, Stephen C

    2007-07-31

    Catalytic wet oxidation (CWO) and wet peroxide oxidation (WPO) of stripped sour water (SSW) from an oil shale refinery was investigated. Greater than 70% total organic carbon (TOC) removal from SSW was achieved using Cu(NO(3))(2) catalysed WO under the following conditions using a glass lined reaction vessel: 200 degrees C, pO(2)=0.5MPa, 3h, [Cu(NO(3))(2)]=67mmol/L. Significant TOC removal ( approximately 31%) also occurred in the system without added oxygen. It is proposed that this is predominantly due to copper catalysed oxidative decarboxylation of organics in SSW based on observed changes in copper oxidation state. Greater than 80% TOC removal was achieved using WPO under the following conditions: 150 degrees C, t=1.5h, [H(2)O(2)]=64g/L. Significantly more TOC could be removed from SSW by adding H(2)O(2) in small doses as opposed to adding the same total amount in one single dose. It was concluded that WPO was a far more effective process for removing odorous compounds from SSW.

  15. Imaging of oil layers, curvature and contact angle in a mixed-wet and a water-wet carbonate rock

    Science.gov (United States)

    Singh, Kamaljit; Bijeljic, Branko; Blunt, Martin J.

    2016-03-01

    We have investigated the effect of wettability of carbonate rocks on the morphologies of remaining oil after sequential oil and brine injection in a capillary-dominated flow regime at elevated pressure. The wettability of Ketton limestone was altered in situ using an oil phase doped with fatty acid which produced mixed-wet conditions (the contact angle where oil contacted the solid surface, measured directly from the images, θ=180°, while brine-filled regions remained water-wet), whereas the untreated rock (without doped oil) was weakly water-wet (θ=47 ± 9°). Using X-ray micro-tomography, we show that the brine displaces oil in larger pores during brine injection in the mixed-wet system, leaving oil layers in the pore corners or sandwiched between two brine interfaces. These oil layers, with an average thickness of 47 ± 17 µm, may provide a conductive flow path for slow oil drainage. In contrast, the oil fragments into isolated oil clusters/ganglia during brine injection under water-wet conditions. Although the remaining oil saturation in a water-wet system is about a factor of two larger than that obtained in the mixed-wet rock, the measured brine-oil interfacial area of the disconnected ganglia is a factor of three smaller than that of oil layers.

  16. Wetting Properties of Single-Wall Carbon Nanotubes

    Science.gov (United States)

    Kriebel, Jennah; Moos, Gunnar; Fasel, Roman; Hertel, Tobias; Ertl, Gerhard

    2001-03-01

    We present a comparative study of the ad-- and desorption kinetics of inert gases (CH_4, Xe, SF_6) and polar molecules (H_2O, MeOH, EthOH) from single--wall carbon nanotube samples and from highly oriented pyrolytic graphite (HOPG). Binding energies and sticking coefficients have been determined under ultra-high vacuum conditions as a function of adsorbate coverage using thermal desorption spectroscopy. At coverages below one mono-layer binding energies of inert gases are found to be substantially higher on tube samples than on HOPG which --- in combination with molecular mechanics calculations --- allows us to identify the preferred low coverage adsorption site. The results indicate that all inert gases studied here should wet nanotube and HOPG surfaces. However, as intermolecular forces within the more polar solvents increase there is a marked change in the wetting behavior of HOPG. In contrast to expectations we find that the wetting properties of SWNT samples cannot be directly related to those of graphite. The origin of this peculiar behavior can be interpreted using our data on ad-- and desorption kinetics in combination with macroscopic contact angle measurements.

  17. Surfactant controlled switching of water-in-oil wetting behaviour of porous silica films grown at oil-water interfaces

    Indian Academy of Sciences (India)

    Manish M Kulkarni; Rajdip Bandyopadhyaya; Ashutosh Sharma

    2008-11-01

    Selective permeation of oil and water across a porous medium, as in oil recovery operations, depends on the preferential wetting properties of the porous medium. We show a profound influence of surfactants in wetting of porous media and thus demonstrate a new route for the control of water-in-oil wetting of porous substrates by changing the concentration of surfactants in an aqueous sub-phase below the substrate. This strategy is employed to engineer partial reversible wetting transitions on a porous silica film. The film itself is grown and stabilized on a flat, macroscopic interface between an oil phase and an aqueous sub-phase. On increasing the surfactant (CTAB) concentration in the sub-phase, contact angle of a water drop (placed on the oil side of the film) changes from 140° to 16° in 25 min by diffusion of the surfactant across the porous film. On further replacement of the sub-phase with pure water, diffusion of the surfactant from the water drop back to the sub-phase was slower, increasing the contact angle in the process from 16° to 90° in 2 h. Wettability control by a cationic surfactant (CTAB) was found to be much faster (6 deg/min) than that offered by an anionic surfactant, SDS (0.05 deg/min). Switching of the surface wettability due to the surfactant diffusion may have implications in oil-water separation, chemical bed reactors and microfluidic devices.

  18. Effect of Substrate-Water Interaction on the Wetting Behavior in Water-Oil and Substrate-Water-Oil Systems

    Institute of Scientific and Technical Information of China (English)

    Yuan Yin-quan; Zou Xian-wu; Jin Zhun-zhi

    2003-01-01

    The effects of the substrate-water interaction on the wetting behavior in water-oil and surfactant-water-oil systems confined by one substrate which has the preferential interaction to one species of particles have been investigated by using the free energy analysis and discontinuous molecular dynamic simulations. As the preferential interaction between the substrate and water particles varies from small repulsion to large attraction, the partial drying, partial wetting and complete wetting state are observed in sequence. In addition, the wetting behavior of surfactant aqueous solution on the substrate is not only dependent on the interaction, but also limited by the maximum equilibrium concentration of surfactants at the interface.

  19. Effect of Substrate-Water Interaction on the Wetting Behavior in Water-Oil and Substrate-Water-Oil Systems

    Institute of Scientific and Technical Information of China (English)

    YuanYin-quan; ZouXian-wu; JinZhun-zhi

    2003-01-01

    The effects of the substrate-water interaction on the wetting behavior in water-oil and surfactant-water-oil systerns confined by one substrate which has the preferential interaction to one species of particles have been investigated by using the free energy analysis and discontinuous molecular dynamic simulations. As the preferential interaction between the substrate and water particles varies from small repulsion to large attraction, the partial drying, partial wetting and complete wetting state are observed in sequence. In addition, the wetting behavior of surfactant aqueous solution on the substrate is not only dependent on the interaction, but also limited by the maximum equilibrium concentration of surfactants at the interface.

  20. Biochar effects on wet and dry regions of the soil water retention curve of a sandy loam

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Moldrup, Per; Sun, Zhencai;

    2014-01-01

    Reported beneficial effects of biochar on soil physical properties and processes include decreased soil density, and increased soil water transport, water holding capacity and retention (mainly for the wet region). Research is limited on biochar effects on the full soil water retention curve (wet...... and dry regions) for a given soil and biochar amendment scenarios. This study evaluates how biochar applied to a sandy loam field at rates from 0 to 50 Mg ha−1 yr–1 in 2011, 2012, or both years (2011+2012) influences the full water retention curve. Inorganic fertilizer and pig slurry were added to all...... region-water retention curve increased with increasing biochar rates....

  1. Wetting properties of AFM probes by means of contact angle measurement

    Science.gov (United States)

    Tao, Zhenhua; Bhushan, Bharat

    2006-09-01

    An atomic force microscopy (AFM) based technique was developed to measure the wetting properties of probe tips. By advancing and receding the AFM tip across the water surface, the meniscus force between the tip and the liquid was measured at the tip-water separation. The water contact angle was determined from the meniscus force. The obtained contact angle results were compared with that by the sessile drop method. It was found that the AFM based technique provided higher contact angle values than the sessile drop method. The mechanisms responsible for the difference are discussed.

  2. Applications of asymmetric nanotextured parylene surface using its wetting and transport properties

    Science.gov (United States)

    Sekeroglu, Koray

    In this thesis, basic digital fluidics devices were introduced using polymeric nanorods (nano-PPX) inspired from nature. Natural inspiration ignited this research by observing butterfly wings, water strider legs, rye grass leaves, and their asymmetric functions. Nano-PPX rods, manufactured by an oblique angle polymerization (OAP) method, are asymmetrically aligned structures that have unidirectional wetting properties. Nano-PPX demonstrates similar functions to the directional textured surfaces of animals and plants in terms of wetting, adhesion, and transport. The water pin-release mechanism on the asymmetric nano-PPX surface with adhesion function provides a great transport property. How the asymmetry causes transport is discussed in terms of hysteresis and interface contact of water droplets. In this study, the transport property of nano-PPX rods is used to guide droplets as well as transporting cargo such as microgels. With the addition of tracks on the nano-PPX rods, the surfaces were transformed into basic digital fluidics devices. The track-assisted nano-PPX has been employed to applications (i.e. sorting, mixing, and carrying cargo particles). Thus, digital fluidics devices fabricated on nano-PPX surface is a promising pathway to assemble microgels in the field of bioengineering. The characterization of the nano textured surface was completed using methods such as Scanning Electron Microscopy, Atomic Force Microscopy, Contact Angle Goniometry, and Fourier Transform Infra-Red Spectroscopy. These methods helped to understand the physical and chemical properties of nano-PPX. Parameters such as advancing and receding contact angles, nanorod tilt angle, and critical drop volumes were utilized to investigate the anisotropic wetting properties of nano-PPX surface. This investigation explained the directional wetting behavior of the surface as well as approaching new design parameters for adjusting surface properties. The nanorod tilt angle was a key parameter

  3. Evaporation of water between two microspheres: how wetting affects drying

    Science.gov (United States)

    Cho, Kun; Kim, Yeseul; Lim, Jun; Kim, Joon Heon; Weon, Byung Mook

    2016-11-01

    When a small volume of water is confined between microparticles or nanoparticles, its evaporation behavior can be influenced by wettability of particles. This situation frequently appears in coating or printing of colloidal drops in which colloidal particles are uniformly dispersed into a liquid. To explore water evaporation between particles, here we study on evaporation dynamics of water between two microspheres by utilizing high-resolution X-ray microscopy for side views and optical microscopy for bottom views. We find that evaporating water gets pinned on microsphere surfaces, due to a force balance among air, water, and microspheres. Side and bottom views of evaporating water enable us to evaluate water curvature evolution around microspheres before and after pinning. Interestingly curvature evolution is controlled by cooperation of evaporation and wetting dynamics. This study would be useful in identifying and controlling of coating or printing for colloidal drops. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2016R1D1A1B01007133).

  4. Wetting characteristic of ceramic to water and adhesive resin.

    Science.gov (United States)

    Oh, Won-Suck; Shen, Chiayi; Alegre, Brandon; Anusavice, Kenneth J

    2002-12-01

    Maximum wetting of ceramic by adhesive resin is required to achieve optimal adhesion of the resin to ceramic. It is unknown whether the adhesion of the resin to the ceramic is affected by the surface topography and wetting by water or the adhesive resin. This study was designed to characterize the effect of surface topography on the wetting of ceramics by water and adhesive resin. Three materials, a veneering ceramic, Eris (ERV), and 2 core ceramics, Empress 1 core ceramic (E1C) and an experimental core ceramic (EXC), were used. Four surface-roughening procedures were used. They included polishing through 1200-grit SiC paper (P), air abrasion with 50 microm Al(2)O(3) (A), etching with 5% hydrofluoric acid gel (E), and a combination of airborne particle abrasion and etching (A/E). Forty bar specimens (15 x 10 x 1.5 mm) were prepared from each material (N=120). Twelve groups of 10 specimens each were prepared for the 4 surface-roughening procedures. Advancing (theta(A)) and receding (theta(R)) contact angles were measured with a CAHN Dynamic Contact Analyzer, on the basis of the Wilhelmy plate technique, with water and adhesive resin. The work of adhesion (W(A)) by the probing media was calculated by use of advancing contact angle data. The data were analyzed by t testing, analysis of variance, and Duncan's tests (alpha=0.05) to determine the statistical significance of differences in the contact angles between ceramic and water or resin as a function of surface roughening. In general, the mean theta(A) values were higher than the mean theta(R) values except for groups of E or A/E specimens with water used as a probing medium. E and A/E treatments yielded the lowest contact angle values, followed by A and P treatments (P<.001). The E1C exhibited the highest mean contact angles, whereas EXC exhibited the lowest mean contact angle except for the theta(R) with resin. The corresponding values for ERV were between those of E1C and EXC except for theta(R) values with resin

  5. Morphology-dependent field emission properties and wetting behavior of ZnO nanowire arrays

    Directory of Open Access Journals (Sweden)

    Ma Li

    2011-01-01

    Full Text Available Abstract The fabrication of three kinds of ZnO nanowire arrays with different structural parameters over Au-coated silicon (100 by facile thermal evaporation of ZnS precursor is reported, and the growth mechanism are proposed based on structural analysis. Field emission (FE properties and wetting behavior were revealed to be strongly morphology dependent. The nanowire arrays in small diameter and high aspect ratio exhibited the best FE performance showing a low turn-on field (4.1 V/μm and a high field-enhancement factor (1745.8. The result also confirmed that keeping large air within the films was an effective way to obtain super water-repellent properties. This study indicates that the preparation of ZnO nanowire arrays in an optimum structural model is crucial to FE efficiency and wetting behavior.

  6. Molecular Structure and Dynamics of Water on Pristine and Strained Phosphorene: Wetting and Diffusion at Nanoscale

    Science.gov (United States)

    Zhang, Wei; Ye, Chao; Hong, Linbi; Yang, Zaixing; Zhou, Ruhong

    2016-12-01

    Phosphorene, a newly fabricated two-dimensional (2D) nanomaterial, has emerged as a promising material for biomedical applications with great potential. Nonetheless, understanding the wetting and diffusive properties of bio-fluids on phosphorene which are of fundamental importance to these applications remains elusive. In this work, using molecular dynamics (MD) simulations, we investigated the structural and dynamic properties of water on both pristine and strained phosphorene. Our simulations indicate that the diffusion of water molecules on the phosphorene surface is anisotropic, with strain-enhanced diffusion clearly present, which arises from strain-induced smoothing of the energy landscape. The contact angle of water droplet on phosphorene exhibits a non-monotonic variation with the transverse strain. The structure of water on transverse stretched phosphorene is demonstrated to be different from that on longitudinal stretched phosphorene. Moreover, the contact angle of water on strained phosphorene is proportional to the quotient of the longitudinal and transverse diffusion coefficients of the interfacial water. These findings thereby offer helpful insights into the mechanism of the wetting and transport of water at nanoscale, and provide a better foundation for future biomedical applications of phosphorene.

  7. Mechanical and microstructural properties of "wet" alginate and composite films containing various carbohydrates.

    Science.gov (United States)

    Harper, B Allison; Barbut, Shai; Smith, Alexandra; Marcone, Massimo F

    2015-01-01

    Composite "wet" alginate films were manufactured from alginate-carbohydrate solutions containing 5% alginate and 0.25% pectin, carrageenan (kappa or iota), potato starch (modified or unmodified), gellan gum, or cellulose (extracted or commercial). The "wet" alginate films were used as a model to understand co-extruded alginate sausage casings that are currently being used by several sausage manufacturers. The mechanical, optical, and microstructural properties of the calcium cross-linked composite films were explored. In addition, the water holding capacity and textural profile analysis properties of the alginate-carbohydrate gels were studied. The results indicate that the mechanical properties of "wet" alginate films/casings can be modified by adding various carbohydrates to them. Alginate films with pectin, carrageenan, and modified potato starch had significantly (P alginate films. The alginate-pectin films also had greater (P alginate films. Alginate films with extracted cellulose, commercial cellulose, and modified potato starch had lower (P alginate control films. Transmission electron microscopy images showed a very uniform alginate network in the control films. Several large cellulose fibers were visible in the films with extracted cellulose, while the cellulose fibers in the films with commercial cellulose were difficult to distinguish. Despite these apparent differences in cellulose fiber length, the 2 cellulose films had similar puncture and tensile properties.

  8. Patterning of polymers: precise channel stamping by optimizing wetting properties

    Energy Technology Data Exchange (ETDEWEB)

    Seemann, Ralf; Kramer, Edward J; Lange, Frederick F [Mitsubishi Chemical Center for Advanced Materials, University of California, Santa Barbara, CA 93106 (United States)

    2004-08-01

    Channel stamping is a soft lithography technique that can be used to fabricate small structures of polymeric materials. This technique is cheap and easy but a considerable drawback is the fact that reproduction of the patterns of the stamp is often imprecise due to the wetting properties of liquid and stamp. In this paper, we report on experiments that reveal the parameters governing the behaviour of liquids in grooves and on edges. Optimizing these parameters leads to better-quality channel-stamped structures and enables the design of sophisticated structured polymeric materials, allowing channels as small as about 100 nm to be fabricated. Moreover, we show that it is even possible to build up a freestanding three-dimensional structure by stamping line patterns on top of each other.

  9. Wetting properties of model interphases coated with defined organic functional groups

    Science.gov (United States)

    Woche, Susanne K.; Goebel, Marc-O.; Guggenberger, Georg; Tunega, Daniel; Bachmann, Joerg

    2013-04-01

    Surface properties of soil particles are of particular interest regarding transport of water and sorption of solutes, especially hazardous xenobiotic species. Wetting properties (e.g. determined by contact angle, CA), governed by the functional groups exposed, are crucial to understand sorption processes in water repellent soils as well as for the geometry of water films sustaining microbial processes on the pore scale. Natural soil particle surfaces are characterized by a wide variety of mineralogical and chemical compounds. Their composition is almost impossible to identify in full. Hence, in order to get a better understanding about surface properties, an option is the usage of defined model surfaces, whereas the created surface should be comparable to natural soil interphases. We exposed smooth glass surfaces to different silane compounds, resulting in a coating covalently bound to the surface and exhibiting defined organic functional groups towards the pore space. The wetting properties as evaluated by CA and the surface free energy (SFE), calculated according to the Acid-Base Theory, were found to be a function of the specific functional group. Specifically, the treated surfaces showed a large variation of CA and SFE as function of chain length and polarity of the organic functional group. The study of wetting properties was accompanied by XPS analysis for selective detection of chemical compounds of the interphase. As the reaction mechanism of the coating process is known, the resulting interphase structure can be modeled based on energetic considerations. A next step is to use same coatings for the defined modification of the pore surfaces of porous media to study transport and sorption processes in complex three phase systems.

  10. Aldehyde concentrations in wet deposition and river waters

    Energy Technology Data Exchange (ETDEWEB)

    Dąbrowska, Agata, E-mail: agatadab@amu.edu.pl; Nawrocki, Jacek

    2013-05-01

    The process of pollutants removal from the atmosphere can be responsible for the appearance of aldehydes in surface waters. We observed that formaldehyde, acetaldehyde, propanal, glyoxal, methylglyoxal and acetone were commonly present in precipitations as well as in surface water samples, while semi-volatile and poorly soluble aldehydes as nonanal and decanal were observed seasonally. Particularly high level of carbonyls concentration was noted after periods of drought and at the beginning of rainy periods. We estimated that ca. 40% of aldehydes from wet precipitations were delivered into river waters. The level of carbonyl concentration in river was positively correlated with specific local meteorological conditions such as solar radiation and ozone concentration, in contrast, there was negative correlation between aldehyde concentration in the river samples and the precipitation intensity. - Highlights: ► Atmosphere pollutants are responsible for the appearance of aldehydes in surface waters. ► Volatile aldehydes are commonly present in precipitations as well as in surface waters. ► Semi-volatile and poorly soluble aldehydes as nonanal and decanal were observed seasonally. ► High concentration of carbonyls were noted after periods of drought and at the beginning of rain. ► Carbonyl concentration in river is correlated to meteorological conditions.

  11. Water wetting of solids during the field demulsification process

    Energy Technology Data Exchange (ETDEWEB)

    Mead, S.L.; Navarrete, R.C. [Akzo Nobel Surface Chemistry, Mississauga, ON (Canada)

    2003-07-01

    This paper presents the results of a bottle test procedure in which surfactants and emulsifiers were blended with typical Lloydminster crude emulsion to obtain a product that is both an efficient demulsifier and a solids control chemical. Petroleum crude is a mixture of oil, water and gas. The separation of these phases plays a critical role in the quality of the final oil. The main problem during oil/water separation of petroleum crude lies with inorganic solids which accumulate at the interface. Anionic and nonionic surfactants were used to help remove the solids at the interface by water wetting the surface of the solids, allowing them to settle. It was demonstrated that surfactants can be used to facilitate solids sedimentation from the oil/water interface without increasing the amount of water in the thief grind-out. The application of both anionic and nonionic surfactants is preferred. The optimum formulation for solids control and the effectiveness of the surfactants can be determined through visual observations during bottle testing. 3 refs., 3 figs., 1 append.

  12. Compound microstructures and wax layer of beetle elytral surfaces and their influence on wetting properties.

    Directory of Open Access Journals (Sweden)

    Mingxia Sun

    Full Text Available A beetles' first line of defense against environmental hazards is their mesothoracic elytra--rigid, protective forewings. In order to study the interaction of these wings with water, the surface microstructures of various beetles' elytra were observed by Environment Scanning Electron Microscopy (ESEM and Atomic Force Microscopy (AFM. Chemistry components were ascertained using X-ray photoelectron spectroscopy (XPS. All the beetles of various habitats (including desert, plant, dung, land and water exhibited compound microstructures on their elytra. The wetting properties of these elytra were identified using an optical contact angle meter. In general the native elytra exhibited hydrophilic or weak hydrophobic properties with contact angles (CAs ranging from 47.5° to 109.1°. After treatment with chloroform, the CAs all increased on the rougher elytral surfaces. The presence of wax is not the only determinant of hydrophobic properties, but rather a combination with microscopic structures found on the surfaces. Irregularities and the presence or absence of tiny cracks, hairs (or setae, pores and protrusions are important factors which influence the wetting properties. Rougher elytral surfaces tended to present a stronger hydrophobicity. Effects on hydrophobicity, such as surface microstructures, chemistry, environment and aging (referring to the time after emergence, are also included and discussed. Our results also provide insights into the motion of water droplets when in contact with beetle elytra.

  13. Self-drying: a gecko's innate ability to remove water from wet toe pads.

    Directory of Open Access Journals (Sweden)

    Alyssa Y Stark

    Full Text Available When the adhesive toe pads of geckos become wet, they become ineffective in enabling geckos to stick to substrates. This result is puzzling given that many species of gecko are endemic to tropical environments where water covered surfaces are ubiquitous. We hypothesized that geckos can recover adhesive capabilities following exposure of their toe pads to water by walking on a dry surface, similar to the active self-cleaning of dirt particles. We measured the time it took to recover maximum shear adhesion after toe pads had become wet in two groups, those that were allowed to actively walk and those that were not. Keeping in mind the importance of substrate wettability to adhesion on wet surfaces, we also tested geckos on hydrophilic glass and an intermediately wetting substrate (polymethylmethacrylate; PMMA. We found that time to maximum shear adhesion recovery did not differ in the walking groups based on substrate wettability (22.7±5.1 min on glass and 15.4±0.3 min on PMMA but did have a significant effect in the non-walking groups (54.3±3.9 min on glass and 27.8±2.5 min on PMMA. Overall, we found that by actively walking, geckos were able to self-dry their wet toe pads and regain maximum shear adhesion significantly faster than those that did not walk. Our results highlight a unexpected property of the gecko adhesive system, the ability to actively self-dry and recover adhesive performance after being rendered dysfunctional by water.

  14. Self-drying: a gecko's innate ability to remove water from wet toe pads.

    Science.gov (United States)

    Stark, Alyssa Y; Wucinich, Nicholas A; Paoloni, Eva L; Niewiarowski, Peter H; Dhinojwala, Ali

    2014-01-01

    When the adhesive toe pads of geckos become wet, they become ineffective in enabling geckos to stick to substrates. This result is puzzling given that many species of gecko are endemic to tropical environments where water covered surfaces are ubiquitous. We hypothesized that geckos can recover adhesive capabilities following exposure of their toe pads to water by walking on a dry surface, similar to the active self-cleaning of dirt particles. We measured the time it took to recover maximum shear adhesion after toe pads had become wet in two groups, those that were allowed to actively walk and those that were not. Keeping in mind the importance of substrate wettability to adhesion on wet surfaces, we also tested geckos on hydrophilic glass and an intermediately wetting substrate (polymethylmethacrylate; PMMA). We found that time to maximum shear adhesion recovery did not differ in the walking groups based on substrate wettability (22.7±5.1 min on glass and 15.4±0.3 min on PMMA) but did have a significant effect in the non-walking groups (54.3±3.9 min on glass and 27.8±2.5 min on PMMA). Overall, we found that by actively walking, geckos were able to self-dry their wet toe pads and regain maximum shear adhesion significantly faster than those that did not walk. Our results highlight a unexpected property of the gecko adhesive system, the ability to actively self-dry and recover adhesive performance after being rendered dysfunctional by water.

  15. Toughness and Hot/Wet Properties of a Novel Modified BMI/Carbon Fiber Composite

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The toughness and hot/wet properties of a novel modified bismaleimide (BMI) 5428/carbon fiber composite was investigated. Results indicate that the prepared BMI/T700 composite owns high toughness, excellent hot/wet properties and mechanical properties. The compression strength after impact (CAl) of 5428/T700 composite is 260 MPa, and the results of hot/wet test show that the long-term service temperature of 5428/T700 composite can maintain at 170°C.

  16. Surface and Wetting Properties of Embiopteran (Webspinner) Nanofiber Silk.

    Science.gov (United States)

    Osborn Popp, Thomas M; Addison, J Bennett; Jordan, Jacob S; Damle, Viraj G; Rykaczewski, Konrad; Chang, Shery L Y; Stokes, Grace Y; Edgerly, Janice S; Yarger, Jeffery L

    2016-05-10

    Insects of the order Embioptera, known as embiopterans, embiids, or webspinners, weave silk fibers together into sheets to make shelters called galleries. In this study, we show that silk galleries produced by the embiopteran Antipaluria urichi exhibit a highly hydrophobic wetting state with high water adhesion macroscopically equivalent to the rose petal effect. Specifically, the silk sheets have advancing contact angles above 150°, but receding contact angle approaching 0°. The silk sheets consist of layered fiber bundles with single strands spaced by microscale gaps. Scanning and transmission electron microscopy (SEM, TEM) images of silk treated with organic solvent and gas chromatography mass spectrometry (GC-MS) of the organic extract support the presence of a lipid outer layer on the silk fibers. We use cryogenic SEM to demonstrate that water drops reside on only the first layer of the silk fibers. The area fraction of this sparse outer silk layers is 0.1 to 0.3, which according to the Cassie-Baxter equation yields an effective static contact angle of ∼130° even for a mildly hydrophobic lipid coating. Using high magnification optical imaging of the three phase contact line of a water droplet receding from the silk sheet, we show that the high adhesion of the drop stems from water pinning along bundles of multiple silk fibers. The bundles likely form when the drop contact line is pinned on individual fibers and pulls them together as it recedes. The dynamic reorganization of the silk sheets during the droplet movement leads to formation of "super-pinning sites" that give embiopteran silk one of the strongest adhesions to water of any natural hydrophobic surface.

  17. Dynamic wetting and de-wetting of thin films of water under the influence of MHz surface acoustic waves

    CERN Document Server

    Altshuler, Gennady

    2015-01-01

    We use both theory and experiment to study the response of partially wetting films of water and surfactant solutions to a propagating MHz vibration in the solid substrate in the form of a Rayleigh surface acoustic wave (SAW). The SAW invokes a drift of mass in the liquid film that, balanced by capillary stress, may support dynamic wetting and de-wetting along the path of the SAW. The motion of the film is governed by a non-dimensional parameter, $\\theta^3/{\\rm We}$, where $\\theta$ is the three phase contact angle and ${\\rm We}\\equiv \\rho U^2H/\\gamma$; $\\rho,~\\gamma$, $H$, and $U$ are the liquid density, liquid/vapour surface tension, film thickness, and the intensity of the SAW at the solid surface, respectively. We show partially wetting films of water and surfactant solutions atop a lithium niobate substrate, for which $\\theta^3/{\\rm We}>1$, undergo qualitatively different dynamics to fully wetting films of silicon oil, for which $\\theta^3/{\\rm We}\\ll1$, and further explore an intermediate parameter region ...

  18. Universal scaling of spontaneous imbibition for water-wet systems

    Science.gov (United States)

    Schmid, K. S.; Geiger, S.

    2012-03-01

    Spontaneous, counter-current imbibition (SI) is a key mechanism in many multiphase flow processes, such as cleanup of nonaqueous phase liquids (NAPLs), bioremediation, or CO2 storage. For interpreting and upscaling laboratory SI data, and modeling and prediction purposes, scaling groups are an essential tool. The question of how to formulate a general scaling group has been debated for over 90 years. Here we propose the first scaling group that incorporates the influence of all parameters on SI that are present in the two-phase Darcy model. The group is derived rigorously from the only known exact analytical solution for spontaneous imbibition by relating the cumulative water phase imbibed to the normalized pore volume. We show the validity of the group by applying it to 42 published SI studies for water-oil and water-air experiments, for a wide range of viscosity ratios, different materials, different initial water saturations, and different length-scales. In all cases, water was the wetting phase. Our group serves as a "master equation" whose generality allows the rigorous prediction of the validity of a large number of specialized scaling groups proposed during the last 90 years. Furthermore, our results give strong evidence that the Darcy model is suitable for describing SI, and that including dynamic effects in capillary pressure is not necessary for counter-current SI, contrary to what has been hypothesized. Two key applications of the group are discussed: First, the group can serve as the long sought after general transfer rate for imbibition used in dual-porosity models. Second, it is the so far missing proportionality constant in imbibition-germination models for plant seeds.

  19. Wet-preserved hemp fibreboard properties improvement with veneering

    Science.gov (United States)

    Kirilovs, E.; Kukle, S.; Gusovius, H.-J.

    2015-03-01

    The initial research describes a new type of fiber boards for the furniture interior design, developed in cooperation with ATB (Leibniz-Institute for Agricultural Engineering) by using a new method of raw materials preparation and specific production technologies of ATB. The main raw materials are aerobically aged hemp stalks. The samples are made of hemp chips with a long preservation time and fastened together with the UF glue. Specimens are 8 mm thick and correspond to a medium-density fiberboard, fitting standard EN622. Due to the fact that non-veneered material can be used only in non-load-bearing constructions, material improving technologies were studied, such as increase of board density, increase of glue percentage, partially substitution of wet-preserved hemp chips with a dry hemp and/or wooden chips to equalize moisture content of obtained mixture. The particular article describes how the new material is veneered with the oak veneer obtaining three-ply composite board with the improved mechanical properties that allows to use these boards in a load-bearing constructions. Tests are performed with the veneered material to determine such parameters as static bending strength (MOR), modulus of elasticity in static bending (MOE), swelling in thickness and hardness.

  20. Characterization of the mechanical properties and structural integrity of T-welded connections repaired by grinding and wet welding

    Energy Technology Data Exchange (ETDEWEB)

    Terán, G., E-mail: gteran@imp.mx [Instituto Mexicano del Petróleo, Eje central Lázaro Cárdenas 152, Col. San Bartolo Atepehuacan, México D.F. CP 07730, México (Mexico); Cuamatzi-Meléndez, R., E-mail: rcuamatzi@imp.mx [Instituto Mexicano del Petróleo, Eje central Lázaro Cárdenas 152, Col. San Bartolo Atepehuacan, México D.F. CP 07730, México (Mexico); Albiter, A., E-mail: aalbiter@imp.mx [Instituto Mexicano del Petróleo, Eje central Lázaro Cárdenas 152, Col. San Bartolo Atepehuacan, México D.F. CP 07730, México (Mexico); Maldonado, C., E-mail: cmzepeda@umich.mx [Instituto de Investigaciones Metalúrgicas, UMSNH, PO Box 52-B, 58000, México (Mexico); Bracarense, A.Q., E-mail: bracarense@ufmg.br [UFMG Departamento de Engeharia Mecánica Belo Horizonte, MG (Brazil)

    2014-04-01

    This paper presents an experimental methodology to characterize the structural integrity and mechanical properties of repaired T-welded connections using in fixed offshore structures. Grinding is employed to remove localized damage like cracking and corrosion and subsequent wet welding can be used to fill the grinded material. But it is important to define the grinding depth and profile in order to maintain structural integrity during the repair. Therefore, in this work different grinding depths were performed, for damage material removal, at the weld toe of the T-welded connections. The grinding was filled by wet welding in a hyperbaric chamber, simulating three different water depths: 50 m, 70 m and 100 m. The electrodes were coated with vinilic varnish, which is cheap and easy to apply. The characterization of the mechanical properties of the T-welded connections was done with standard tensile, hardness and Charpy tests; microstructure and porosity analysis were also performed. The samples were obtained from the welded connections in regions of the wet weld beads. The test results were compared with the mechanical properties of the T-welded connections welded in air conditions performed by other authors. The results showed that the wet welding technique performed in this work produced good mechanical properties of the repaired T-welded connection. The mechanical properties, measured in wet conditions, for 6 mm grinding depth, were similar for the 3 different water depths measured in air conditions. But for 10 mm grinding depth, the values of the mechanical properties measured in wet conditions were quite lower than that for air conditions for the 3 water depths. However a porosity analysis, performed with a Scanning Electronic Microscopy (SEM), showed that the level of porosity in the resulted wet weld beads is in the range of that published in the literature and some samples revealed lower level of porosity. The main resulting microstructure was polygonal

  1. Playing with Water Drops: From Wetting to Optics through Electrostatics

    Science.gov (United States)

    Domps, A.; Roques-Carmes, T.

    2011-01-01

    We present a consistent series of activities, including experiments and basic computational studies, investigating the shape and optical properties of water drops in connection with novel technological devices. Most of the work can be carried out with simple teaching equipment and is well suited to undergraduate students. Firstly, we show how the…

  2. Fingerlike wetting patterns in two water-repellent loam soils

    NARCIS (Netherlands)

    Dekker, L.W.; Ritsema, C.J.

    1995-01-01

    In soils with fingered flow, surface-applied solutes can reach the groundwater more rapidly than in the case of homogeneous wetting. This study was undertaken to demonstrate the occurrence of finger-like wetting patterns in a silt loam soil and a silty clay loam soil, and to investigate the

  3. Wetting properties of liquid lithium on lithium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Krat, S.A., E-mail: stepan.krat@gmail.com [Center for Plasma Material Interactions, Department of Nuclear, Plasma, and Radiological Engineering, University Illinois at Urbana-Champaign, Urbana (United States); National Research Nuclear University MEPhI, Moscow (Russian Federation); Popkov, A.S. [Center for Plasma Material Interactions, Department of Nuclear, Plasma, and Radiological Engineering, University Illinois at Urbana-Champaign, Urbana (United States); National Research Nuclear University MEPhI, Moscow (Russian Federation); Gasparyan, Yu. M.; Pisarev, A.A. [National Research Nuclear University MEPhI, Moscow (Russian Federation); Fiflis, Peter; Szott, Matthew; Christenson, Michael; Kalathiparambil, Kishor; Ruzic, David N. [Center for Plasma Material Interactions, Department of Nuclear, Plasma, and Radiological Engineering, University Illinois at Urbana-Champaign, Urbana (United States)

    2017-04-15

    Highlights: • Contact angles of liquid lithium and Li{sub 3}N, Li{sub 2}O, Li{sub 2}CO{sub 3} were measured. • Liquid lithium wets lithium compounds at relatively low temperatures: Li{sub 3}N at 257 °C, Li{sub 2}O at 259 °C, Li{sub 2}CO{sub 3} at 323 °C. • Li wets Li{sub 2}O and Li{sub 3}N better than previously measured fusion-relevant materials (W, Mo, Ta, TZM, stainless steel). • Li wets Li{sub 2}CO{sub 3} better than most previously measured fusion-relevant materials (W, Mo, Ta). - Abstract: Liquid metal plasma facing components (LMPFC) have shown a potential to supplant solid plasma facing components materials in the high heat flux regions of magnetic confinement fusion reactors due to the reduction or elimination of concerns over melting, wall damage, and erosion. To design a workable LMPFC, one must understand how liquid metal interacts with solid underlying structures. Wetting is an important factor in such interaction, several designs of LMPFC require liquid metal to wet the underlying solid structures. The wetting of lithium compounds (lithium nitride, oxide, and carbonate) by 200 °C liquid lithium at various surface temperature from 230 to 330 °C was studied by means of contact angle measurements. Wetting temperatures, defined as the temperature above which the contact angle is less than 90°, were measured. The wetting temperature was 257 °C for nitride, 259 °C for oxide, and 323 °C for carbonate. Surface tensions of solid lithium compounds were calculated from the contact angle measurements.

  4. Reactive wetting properties of TiO2 nanoparticles predicted by ab initio molecular dynamics simulations.

    Science.gov (United States)

    Brandt, Erik G; Agosta, Lorenzo; Lyubartsev, Alexander P

    2016-07-21

    Small-sized wet TiO2 nanoparticles have been investigated by ab initio molecular dynamics simulations. Chemical and physical adsorption of water on the TiO2-water interface was studied as a function of water content, ranging from dry nanoparticles to wet nanoparticles with monolayer coverage of water. The surface reactivity was shown to be a concave function of water content and driven by surface defects. The local coordination number at the defect was identified as the key factor to decide whether water adsorption proceeds through dissociation or physisorption on the surface. A consistent picture of TiO2 nanoparticle wetting at the microscopic level emerges, which corroborates existing experimental data and gives further insight into the molecular mechanisms behind nanoparticle wetting. These calculations will facilitate the engineering of metal oxide nanoparticles with a controlled catalytic water activity.

  5. Improvement of surface wetting properties of poly(p-phenylene benzoxazole) by incorporation of ionic groups

    Energy Technology Data Exchange (ETDEWEB)

    Luo Kaiqing [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 200051 (China); Jin Junhong [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 200051 (China); Yang Shenglin [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 200051 (China); Li Guang [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 200051 (China)]. E-mail: lig@dhu.edu.cn; Jiang Jianming [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Material Science and Engineering, Donghua University, Shanghai 200051 (China)

    2006-07-25

    Modified poly(p-phenylene benzoxazole), SPBO, containing ionic sulfonate groups was synthesized by polycondensation of the corresponding monomers in polyphosphoric acid. SPBO fiber was spun via a dry-jet wet-spinning technique. The wetting property of poly(p-phenylene benzoxazole) (PBO) fiber and SPBO fiber were measured by contact angle analysis, and the interfacial shear strength (IFSS) between fibers and epoxy was determined by microbond pull-out testing. The contact angles of water and ethanol on SPBO fiber surface get smaller, and the wetting process becomes faster. The surface free energy of SPBO fiber increases to 38.9 mJ m{sup -2}, which is 9.6% higher than that of PBO fiber. Furthermore the ionic introducing leads to a 23% increase in IFSS from 8.2 MPa for PBO/epoxy to 10.1 MPa for SPBO/epoxy. It could be expected that the failure mode may change from fiber/matrix interface adhesive failure to partly cohesive failure mode.

  6. The effect of pH modification on wetting kinetics of a naturally water repellent coniferous soil

    Science.gov (United States)

    Amer, Ahmad; Diehl, Dörte; Schaumann, Gabriele

    2017-04-01

    The interfacial dynamics of soil-water interactions are significantly affected by the hydrophobic properties of organic matter. The underlying mechanisms responsible for the development of soil water repellency (SWR) are still under discussion. Various environmental factors control the appearance and degree of SWR. The wetting of soil greatly depends on the physicochemical characteristics of soil surfaces which in turn depends on pH. In this contribution, we propose a mechanism for the change in SWR that is observed upon the artificial change in soil pH. Wetting kinetics were studied by the time dependent sessile drop measurements (TISED) of the contact angle, the work of spreading and the drop base diameter as time elapsed under controlled relative humidity. Modification of pH strongly affected the wetting kinetics, suggesting maximum wetting resistance at the control pH (3.60) and with decreased wetting resistance as pH was changed in either direction. The enhancement of the wetting kinetics by artificial modification of soil pH can be attributed to the chemical modification in organic materials coating soil particles based on the magnitude of spreading activation energy and the hydrophilic/hydrophobic moieties ratio of treated soil samples measured by (XPS & MIR spectroscopy). On the basis of our current state of knowledge, we propose that acid and base catalyzed hydrolysis-condensation reactions as dominant processes responsible for the chemical nature of SWR.

  7. Growth and wetting of water droplet condensed between micron-sized particles and substrate

    Science.gov (United States)

    Quang, Tran Si Bui; Leong, Fong Yew; An, Hongjie; Tan, Beng Hau; Ohl, Claus-Dieter

    2016-08-01

    We study heterogeneous condensation growth of water droplets on micron-sized particles resting on a level substrate. Through numerical simulations on equilibrium droplet profiles, we find multiple wetting states towards complete wetting of the particle. Specifically, a partially wetting droplet could undergo a spontaneous transition to complete wetting during condensation growth, for contact angles above a threshold minimum. In addition, we find a competitive wetting behavior between the particle and the substrate, and interestingly, a reversal of the wetting dependence on contact angles during late stages of droplet growth. Using quasi-steady assumption, we simulate a growing droplet under a constant condensation flux, and the results are in good agreement with our experimental observations. As a geometric approximation for particle clusters, we propose and validate a pancake model, and with it, show that a particle cluster has greater wetting tendency compared to a single particle. Together, our results indicate a strong interplay between contact angle, capillarity and geometry during condensation growth.

  8. Variations of dryness/wetness across China: Changing properties, drought risks, and causes

    Science.gov (United States)

    Huang, Qingzhong; Zhang, Qiang; Singh, Vijay P.; Shi, Peijun; Zheng, Yongjie

    2017-08-01

    Variations of wetness/dryness across China during 1949-2014 in both space and time were investigated using the grid climate data of Time-Series (TS) Version 3.23. The Standardized Precipitation Evapotranspiration Index (SPEI) was used to evaluate the wetness and dryness conditions. Results indicated that the regions that experienced a drying/wetting tendency are similar in area, and the regions dominated by a drying tendency are east of 100°E and the regions experiencing a wetting tendency are west of 100°E. A significant wetting tendency was observed in the northern parts of northwestern China, Qaidam Basin and northeastern parts of the Tibetan Plateau. Analysis of water vapor flux by air mass propagation indicated that dry regimes are attributed to continental air mass and wet regimes to oceanic air mass. Propagation of water vapor flux can thus explain the occurrence of wetness/dryness events in both space and time. The shortening of periodicity or increased frequency of wet and/or dry regimes implies intensifying and amplifying wet and dry regimes across China. The results of this study would be useful for the management of agricultural irrigation and water resources across China in a changing environment.

  9. Wetting behaviour during evaporation and condensation of water microdroplets on superhydrophobic patterned surfaces.

    Science.gov (United States)

    Jung, Y C; Bhushan, B

    2008-01-01

    Superhydrophobic surfaces have considerable technological potential for various applications due to their extreme water repellent properties. The superhydrophobic surfaces may be generated by the use of hydrophobic coating, roughness and air pockets between solid and liquid. The geometric effects and dynamic effects, such as surface waves, can destroy the composite solid-air-liquid interface. The relationship between the water droplet size and geometric parameters governs the creation of composite interface and affects transition from solid-liquid interface to composite interface. Therefore, it is necessary to study the effect of droplets of various sizes. We have studied the effect of droplet size on contact angle by evaporation using droplets with radii ranging from about 300 to 700 microm. Experimental and theoretical studies of the wetting properties of silicon surfaces patterned with pillars of two different diameters and heights with varying pitch values are presented. We propose a criterion where the transition from Cassie and Baxter regime to Wenzel regime occurs when the droop of the droplet sinking between two asperities is larger than the depth of the cavity. The trends are explained based on the experimental data and the proposed transition criteria. An environmental scanning electron microscopy (ESEM) is used to form smaller droplets of about 20 microm radius and measure the contact angle on the patterned surfaces. The investigation has shown that ESEM provides a new approach to wetting studies on the microscale.

  10. Biochar effects on wet and dry regions of the soil water retention curve of a sandy loam

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Moldrup, Per; Sun, Zhencai

    2014-01-01

    Reported beneficial effects of biochar on soil physical properties and processes include decreased soil density, and increased soil water transport, water holding capacity and retention (mainly for the wet region). Research is limited on biochar effects on the full soil water retention curve (wet...... and dry regions) for a given soil and biochar amendment scenarios. This study evaluates how biochar applied to a sandy loam field at rates from 0 to 50 Mg ha−1 yr–1 in 2011, 2012, or both years (2011+2012) influences the full water retention curve. Inorganic fertilizer and pig slurry were added to all...... treatments. Six months after the last biochar application, intact and disturbed soil samples were collected for analyses. Soil water retention was measured from −1 kPa to −100 kPa using tension tables and ceramic plates and from −10 MPa to −480 MPa using a Vapor Sorption Analyzer. Soil specific area...

  11. Water Productivity of Irrigated Rice under Transplanting, Wet Seeding and Dry Seeding Methods of Cultivation

    Directory of Open Access Journals (Sweden)

    Murali, NS.

    1997-01-01

    Full Text Available Water productivity (WP of irrigated lowland rice was determined during the 1994 dry (January to May and wet (August to December seasons on a heavy clay acid sulphate soil. Treatments consisted of three cultivation methods : transplanted rice, pregerminated seeds broadcasted on puddled soil (wet seeding and dry seeds broadcasted on unpuddled soil (dry seeding. In wet and dry seeded plots, continuous standing water condition was initiated 17 days after sowing. Total water requirement for rice production was highest in transplanted plots (755 mm in wet season and 1154 mm in dry season and was lowest in dry seeded plots (505 mm in wet season and 1040 mm in dry season. Dry seeding required no water for land preparation but transplanting and wet seeding methods required 18 - 20 % of total water requirement in dry season and 27 - 29 % in wet season. Total percolation was maximum (99 mm in wet season and 215 mm in dry season in dry seeding method and was minimum (62 mm in wet season and 94 mm in dry season in transplanting method. In dry and wet seeding methods, daily percolation gradually decreased with the age of the crop. Total seepage loss did not show any significant difference between the cultivation methods in the two seasons. Grain yield was not affected by the three cultivation methods in both seasons. Water productivity (the ratio between grain yield and total amount of water used in production was 3.5 - 4.1 kg ha-1 mm-1, 3.8 - 4.4 kg ha-1 mm-1 and 4.1 - 5.5 kg ha-1 mm-1 in transplanted, wet seeded and dry seeded rice, respectively. Labour requirement for land preparation and sowing was maximum in transplanted (219 - 226 man-hours ha-1 followed by wet (104 -112 man-hours ha-1 and dry seeded (94 - 99 man-hours ha-1 methods. However, in wet season extra labour (77 man-hours ha-1 was required for weeding after crop establishment in dry and wet seeding methods. Crop maturity was 20 days earlier in wet and dry seeding methods compared to

  12. Microscale Mechanism of Age Dependent Wetting Properties of Prickly Pear Cacti (Opuntia).

    Science.gov (United States)

    Rykaczewski, Konrad; Jordan, Jacob S; Linder, Rubin; Woods, Erik T; Sun, Xiaoda; Kemme, Nicholas; Manning, Kenneth C; Cherry, Brian R; Yarger, Jeffery L; Majure, Lucas C

    2016-09-13

    Cacti thrive in xeric environments through specialized water storage and collection tactics such as a shallow, widespread root system that maximizes rainwater absorption and spines adapted for fog droplet collection. However, in many cacti, the epidermis, not the spines, dominates the exterior surface area. Yet, little attention has been dedicated to studying interactions of the cactus epidermis with water drops. Surprisingly, the epidermis of plants in the genus Opuntia, also known as prickly pear cacti, has water-repelling characteristics. In this work, we report that surface properties of cladodes of 25 taxa of Opuntia grown in an arid Sonoran climate switch from water-repelling to superwetting under water impact over the span of a single season. We show that the old cladode surfaces are not superhydrophilic, but have nearly vanishing receding contact angle. We study water drop interactions with, as well as nano/microscale topology and chemistry of, the new and old cladodes of two Opuntia species and use this information to uncover the microscopic mechanism underlying this phenomenon. We demonstrate that composition of extracted wax and its contact angle do not change significantly with time. Instead, we show that the reported age dependent wetting behavior primarily stems from pinning of the receding contact line along multilayer surface microcracks in the epicuticular wax that expose the underlying highly hydrophilic layers.

  13. Electric and Thermal Properties of Wet Cable 10kV and 15kV

    Directory of Open Access Journals (Sweden)

    K. Rajagopala

    2012-11-01

    Full Text Available The increased temperature of the cable insulation with rising load currents, are known to accelerate the formation of water and electric trees in cables which ultimately lead to cables failure. There are several factors which will determine the thermal and electrical behaviour of a given wet cable installation. These include the assumed ampacity, the cable construction and circumstances of installation, the thermal properties of the surrounding soil and the electrical properties. The work presented in this paper involves the use of COMSOL multiphysics finite element software to develop an integrated electrical, thermal model with 5micro meter and 2.5 micro meter water bubble radius. The presence of water tree results in the reduction of their dielectric strength. Here the finite element simulation technique is used to evaluate the electric field, potential and temperature distribution inside the 10 kV and 15 kV power cables. A model that illustrates the water-dielectric interface within the cable insulation system is proposed.

  14. Wetting and superhydrophobic properties of PECVD grown hydrocarbon and fluorinated-hydrocarbon coatings

    Energy Technology Data Exchange (ETDEWEB)

    Sarkar, D.K., E-mail: dsarkar@uqac.ca [Canada Research Chair on Atmospheric Icing Engineering of Power Networks (INGIVRE) and Industrial Chair on Atmospheric Icing of Power Network Equipment (CIGELE), Universite du Quebec a Chicoutimi UQAC, 555 Boulevard de l' Universite, Chicoutimi, Quebec, G7H 2B1 (Canada); Farzaneh, M. [Canada Research Chair on Atmospheric Icing Engineering of Power Networks (INGIVRE) and Industrial Chair on Atmospheric Icing of Power Network Equipment (CIGELE), Universite du Quebec a Chicoutimi UQAC, 555 Boulevard de l' Universite, Chicoutimi, Quebec, G7H 2B1 (Canada); Paynter, R.W. [INRS-EMT, 1650 boul. Lionel-Boulet, Varennes, Quebec, J3X 1S2 (Canada)

    2010-03-15

    Wetting characteristics of micro-nanorough substrates of aluminum and smooth silicon substrates have been studied and compared by depositing hydrocarbon and fluorinated-hydrocarbon coatings via plasma enhanced chemical vapor deposition (PECVD) technique using a mixture of Ar, CH{sub 4} and C{sub 2}F{sub 6} gases. The water contact angles on the hydrocarbon and fluorinated-hydrocarbon coatings deposited on silicon substrates were found to be 72 deg. and 105 deg., respectively. However, the micro-nanorough aluminum substrates demonstrated superhydrophobic properties upon coatings with fluorinated-hydrocarbon providing a water contact angle of {approx}165 deg. and contact angle hysteresis below 2 deg. with water drops rolling off from those surfaces while the same substrates showed contact angle of 135 deg. with water drops sticking on those surfaces. The superhydrophobic properties is due to the high fluorine content in the fluorinated-hydrocarbon coatings of {approx}36 at.%, as investigated by X-ray photoelectron spectroscopy (XPS), by lowering the surface energy of the micro-nanorough aluminum substrates.

  15. Nano-Wilhelmy investigation of dynamic wetting properties of AFM tips through tip-nanobubble interaction

    OpenAIRE

    2016-01-01

    The dynamic wetting properties of atomic force microscopy (AFM) tips are of much concern in many AFM-related measurement, fabrication, and manipulation applications. In this study, the wetting properties of silicon and silicon nitride AFM tips are investigated through dynamic contact angle measurement using a nano-Wilhelmy balance based method. This is done by capillary force measurement during extension and retraction motion of AFM tips relative to interfacial nanobubbles. The working princi...

  16. Water Properties Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this Phase I project, Kaitech proposes to design a Water Properties Sensor (WPS) sensing system to synchronously measure the spectral inherent and apparent...

  17. Water Properties Sensor Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this Phase II project, Kaitech proposes to develop and demonstrate a Water Properties Sensor (WPS) sensing system to synchronously measure the spectral inherent...

  18. Physico-chemical examination of the displacement mechanism using polyacrylamide solutions. Part 4. Examination of flow characteristics in water-wet and oil-wet porous systems

    Energy Technology Data Exchange (ETDEWEB)

    Lakatos, T.

    1975-07-01

    Flow characteristics of polymer solutions and carrier phases (formation water) are examined in water-wet and oil-wet systems. According to experimental results, fluids (polymer solutions, formation water, distilled water) will move in oil-wet porous rocks with their original mobility and viscosity and no apparent permeability reduction will take place. The cause of this phenomenon is attributed to the fact that the sorption loss of polyacrylamide on oil-wet rock surfaces is nil, and the carrying effect of carrier phases is unrestricted. A disadvantageous consequence of the lower mobility ratio and of the apparent permeability reduction is that identical displacement and areal sweep efficiency can be attained in an oil-wet reservoir at considerably higher costs (polymer amounts) only. Examinations have been performed in a compatible polymer-rock system. (12 refs.)

  19. Reactive wetting properties of TiO2 nanoparticles predicted by ab initio molecular dynamics simulations

    Science.gov (United States)

    Brandt, Erik G.; Agosta, Lorenzo; Lyubartsev, Alexander P.

    2016-07-01

    Small-sized wet TiO2 nanoparticles have been investigated by ab initio molecular dynamics simulations. Chemical and physical adsorption of water on the TiO2-water interface was studied as a function of water content, ranging from dry nanoparticles to wet nanoparticles with monolayer coverage of water. The surface reactivity was shown to be a concave function of water content and driven by surface defects. The local coordination number at the defect was identified as the key factor to decide whether water adsorption proceeds through dissociation or physisorption on the surface. A consistent picture of TiO2 nanoparticle wetting at the microscopic level emerges, which corroborates existing experimental data and gives further insight into the molecular mechanisms behind nanoparticle wetting. These calculations will facilitate the engineering of metal oxide nanoparticles with a controlled catalytic water activity.Small-sized wet TiO2 nanoparticles have been investigated by ab initio molecular dynamics simulations. Chemical and physical adsorption of water on the TiO2-water interface was studied as a function of water content, ranging from dry nanoparticles to wet nanoparticles with monolayer coverage of water. The surface reactivity was shown to be a concave function of water content and driven by surface defects. The local coordination number at the defect was identified as the key factor to decide whether water adsorption proceeds through dissociation or physisorption on the surface. A consistent picture of TiO2 nanoparticle wetting at the microscopic level emerges, which corroborates existing experimental data and gives further insight into the molecular mechanisms behind nanoparticle wetting. These calculations will facilitate the engineering of metal oxide nanoparticles with a controlled catalytic water activity. Electronic supplementary information (ESI) available: Simulation data on equilibration of energies and structures (root-mean-square-deviations and

  20. Effects of fibrous fillers on friction and wear properties of polytetrafluoroethylene composites under dry or wet conditions

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The friction and wear behavior and mechanism as well as the mechanical properties of polytetrafluoroethylene (PTFE) composites filled with potassium titanate whiskers (PTW) and short carbon fibers (CF) under dry, wet and alkaline conditions were investigated. Experiments indicated that owing to appropriate cooling and boundary lubricating effects, the filled PTFE composites showed much lower frictional coefficient and better wear resistance under alkaline than dry and wet sliding conditions. The wear resistance of carbon-fiber-filled PTFE was much better than that of potassium titanate-whisker-filled PTFE composites in water. Results also showed that the transfer film on counterpart rings was significantly hindered by water and alkali. Hydrophilic-filler-reinforced PTFE composites yield higher wear rate when sliding under water.

  1. Modification of wetting property of Inconel 718 surface by nanosecond laser texturing

    Science.gov (United States)

    Yang, Z.; Tian, Y. L.; Yang, C. J.; Wang, F. J.; Liu, X. P.

    2017-08-01

    Topographic and wetting properties of Inconel 718 (IN718) surfaces were modified via nanosecond laser treatment. In order to investigate surface wetting behavior without additional post treatment, three kinds of microstructures were created on IN718 surfaces, including line pattern, grid pattern and spot pattern. From the viewpoint of surface morphology, the results show that laser ablated grooves and debris significantly altered the surface topography as well as surface roughness compared with the non-treated surfaces. The effects of laser parameters, such as laser scanning speed and laser power, on surface features were also discussed. We have observed the laser treated surfaces of IN718 showed very high hydrophilicity just after laser ablation under ambient air condition. And this hydrophilic property has changed rapidly to the other state, very high hydrophobicity over about 20 days. Further experiments and analysis have been carried out so as to investigate this phenomenon. Based on the XPS analysis, the results indicate that the change of wetting property from hydrophilic to hydrophobic over time may be due to the surface chemistry modifications, especially carbon content. After the contact angles reached steady state, the maximum water contact angle (WCA) for line-patterned and grid-patterned surfaces increased to 152.3 ± 1.2° and 156.8 ± 1.1° with the corresponding rolling angle (RA) of 8.8 ± 1.1° and 6.5 ± 0.8°, respectively. These treated IN718 surfaces exhibited superhydrophobic property. However, the maximum WCA for the spot-patterned surfaces just increased to 140.8 ± 2.8° with RA above 10°. Therefore, it is deduced that laser-inscribed modification of surface wettability has high sensitivity to surface morphology and surface chemical compositions. This work can be utilized to optimize the laser processing parameters so as to fabricate desired IN718 surfaces with hydrophobic or even superhydrophobic property and thus extend the applications

  2. Revisiting the droplet simulation approach to derive force-field parameters for water on molybdenum disulfide from wetting angle measurements

    Science.gov (United States)

    Leroy, Frédéric

    2016-10-01

    Owing to its peculiar electronic properties, molybdenum disulfide (MoS2) has been the subject of a growing number of studies in the recent years. In applications, this material and other transition metal dichalcogenides (TMDs) may have to interact with a liquid or polymer phase as well as solutions of biomolecules. It is therefore of primary importance to understand the wetting and adhesion properties of TMDs. Starting from existing models, we derive Lennard-Jones parameters for the interaction between water and the basal plane of MoS2 that are consistent with recent wetting experiments. Molecular dynamics simulations indicate that a stack of only two MoS2 monolayers is necessary to capture the wetting behavior of bulk MoS2. It is found that the Coulomb interaction between water and monolayer and bilayer MoS2 plays no role in the related interfacial thermodynamics. Calculations with the optimized parameters show that the depth of the well of the interaction potential between water and bulk MoS2 is of the order of 8.2 kJ/mol. Such a value is comparable with what was found for graphite and consistent with the fact that the wetting angles of water on graphite and MoS2 are almost equal. The derivation of the force-field parameters is performed using a methodology which, contrary to previous studies, makes a consistent use of droplet calculations. The results of our work should find application in further simulation studies on the wetting behavior of TMDs and other dispersive materials.

  3. Effects of Mo, Ti and B on Microstructure and Mechanical Properties of Underwater Wet Welding Joints

    Science.gov (United States)

    Liu, Duo; Guo, Ning; Xu, Changsheng; Li, Hongliang; Yang, Ke; Feng, Jicai

    2017-03-01

    Alloy components are designed and transferred into weld metal via electrode covering to address the deterioration of the microstructure and mechanical properties of underwater wet welds. Emphasis is placed on studying the effects that the Mo, Ti and B contents have on the microstructure, tensile strength and low-temperature toughness of the underwater wet welding joint. The as-welded metal obtained at a water depth of 3 m is analyzed. The results indicate that the addition of Mo depresses the formation of coarse pro-eutectoid ferrite. However, a higher Mo content (0.609 wt.%) results in the formation of lath-like bainite and martensite, which are harmful to the plasticity and toughness of the weld. Acicular ferrite nucleation increases with the combined addition of Ti and B. The deposited metal with the optimum alloy components ratio achieves good plasticity and toughness while maintaining its tensile strength of 592 MPa, with the impact toughness at 0 °C and elongation reaching 53.34 J and 16.2%, respectively.

  4. Catalytic properties of carbon materials for wet oxidation of aniline

    Energy Technology Data Exchange (ETDEWEB)

    Gomes, Helder T. [Laboratorio de Catalise e Materiais (LCM), Laboratorio Associado LSRE/LCM, Departamento de Engenharia Quimica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Departamento de Tecnologia Quimica e Biologica, Escola Superior de Tecnologia e de Gestao, Instituto Politecnico de Braganca, Campus de Santa Apolonia, 5300-857 Braganca (Portugal); Machado, Bruno F.; Ribeiro, Andreia; Moreira, Ivo; Rosario, Marcio; Silva, Adrian M.T.; Figueiredo, Jose L. [Laboratorio de Catalise e Materiais (LCM), Laboratorio Associado LSRE/LCM, Departamento de Engenharia Quimica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Faria, Joaquim L. [Laboratorio de Catalise e Materiais (LCM), Laboratorio Associado LSRE/LCM, Departamento de Engenharia Quimica, Faculdade de Engenharia, Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)], E-mail: jlfaria@fe.up.pt

    2008-11-30

    A mesoporous carbon xerogel with a significant amount of oxygen functional groups and a commercial activated carbon, were tested in the catalytic wet air oxidation of aniline at 200 deg. C and 6.9 bar of oxygen partial pressure. Both carbon materials showed high activity in aniline and total organic carbon removal, a clear increase in the removal efficiency relatively to non-catalytic wet air oxidation being observed. The best results in terms of aniline removal were obtained with carbon xerogel, an almost complete aniline conversion after 1 h oxidation with high selectivity to non-organic compounds being achieved. The materials were characterized by thermogravimetric analysis, temperature programmed desorption, N{sub 2} adsorption and scanning electron microscopy, in order to relate their performances to the chemical and textural characteristics. It was concluded that the removal efficiency, attributed to both adsorption and catalytic activity, is related to the mesoporous character of the materials and to the presence of specific oxygen containing functional groups at their surface. The effect of catalytic activity was found to be more important in the removal of aniline than the effect of adsorption at the materials surface. The results obtained indicate that mesoporous carbon xerogels are promising catalysts for CWAO processes.

  5. Catalytic properties of carbon materials for wet oxidation of aniline.

    Science.gov (United States)

    Gomes, Helder T; Machado, Bruno F; Ribeiro, Andreia; Moreira, Ivo; Rosário, Márcio; Silva, Adrián M T; Figueiredo, José L; Faria, Joaquim L

    2008-11-30

    A mesoporous carbon xerogel with a significant amount of oxygen functional groups and a commercial activated carbon, were tested in the catalytic wet air oxidation of aniline at 200 degrees C and 6.9 bar of oxygen partial pressure. Both carbon materials showed high activity in aniline and total organic carbon removal, a clear increase in the removal efficiency relatively to non-catalytic wet air oxidation being observed. The best results in terms of aniline removal were obtained with carbon xerogel, an almost complete aniline conversion after 1h oxidation with high selectivity to non-organic compounds being achieved. The materials were characterized by thermogravimetric analysis, temperature programmed desorption, N(2) adsorption and scanning electron microscopy, in order to relate their performances to the chemical and textural characteristics. It was concluded that the removal efficiency, attributed to both adsorption and catalytic activity, is related to the mesoporous character of the materials and to the presence of specific oxygen containing functional groups at their surface. The effect of catalytic activity was found to be more important in the removal of aniline than the effect of adsorption at the materials surface. The results obtained indicate that mesoporous carbon xerogels are promising catalysts for CWAO processes.

  6. Why do pigeon feathers repel water? Hydrophobicity of pennae, Cassie-Baxter wetting hypothesis and Cassie-Wenzel capillarity-induced wetting transition.

    Science.gov (United States)

    Bormashenko, Edward; Bormashenko, Yelena; Stein, Tamir; Whyman, Gene; Bormashenko, Ester

    2007-07-01

    Wetting of pigeon feathers has been studied. It was demonstrated that the Cassie-Baxter wetting regime is inherent for pigeon pennae. The water drop, supported by network formed by barbs and barbules, sits partially on air pockets. Small static apparent angle hysteresis justifies the Cassie-Baxter wetting hypothesis. A twofold structure of a feather favors large contact angles and provides its water repellency. Cassie-Wenzel transition has been observed under drop evaporation, when drop radius becomes small enough for capillarity-induced water penetration into the protrusions, formed by barbules.

  7. Investigation of Parameters Affecting Gypsum Dewatering Properties in a Wet Flue Gas Desulphurization Pilot Plant

    OpenAIRE

    Hansen, Brian Brun; Kiil, Søren

    2012-01-01

    Wet flue gas desulphurization (FGD) plants with forced oxidation, installed at coal and oil fired power plants for removal of SO2(g), must produce gypsum of high quality. However, quality issues such as an excessive moisture content, due to poor gypsum dewatering properties, may occur from time to time. In this work, the particle size distribution, morphology, and filtration rate of wet FGD gypsum formed in a pilot-scale experimental setup, operated in forced oxidation mode, have been studied...

  8. Changes in Structure and Properties of Soybean Protein/Poly (vinyl alcohol) Blended Fibers Subjected to Wet Heat Treatment

    Institute of Scientific and Technical Information of China (English)

    TANG Ren-cheng; XU Wei; SONG Xin-yuan

    2006-01-01

    The properties of soybean protein/poly (vinyl alcohol) (SP/PVA) blended fibers subjected to wet heat treatment in hot water were measured. The structure of fibers was investigated by scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, wide-angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). The results show that the wet heat treatment above 100℃ has a great influence on the properties and structure of SP/PVA blended fibers. After the wet heat treatment at high temperature, the fibers exhibit the severe shrinking and yellowing, the great decrease in breaking strength and adhesive aggregation. The fibers show a broader main X-ray diffraction peak with the disappearance of minor diffraction peaks, a double DSC melting behavior with the peak temperatures of 215 and 233℃, and a weaker intensity of crystallization-sensitive absorbance peak of PVA component at 1142 cm-1. Therefore it is concluded that the wet heat treatment above 100℃ leads to a change in the crystalline structure of fibers and the scission and degradation of PVA macromolecular chains.

  9. Wet-dry cycles effect on ash water repellency. A laboratory experiment.

    Science.gov (United States)

    Pereira, Paulo; Cerdà, Artemi; Oliva, Marc; Mataix, Jorge; Jordán, Antonio

    2014-05-01

    In the immediate period after the fire, the ash layer has a strong influence on soil hydrological processes, as runoff, infiltration and erosion. Ash is very dynamic in the space and time. Until the first rainfall periods, ash is (re)distributed by the wind. After it can cover the soil surface, infiltrate or transported to other areas by water transport (Pereira et al., 2013a, b). This will have strong implications on nutrient redistribution and vegetation recovery. Ash layer may affect soil water repellency in different ways, depending on fire severity, soil properties and vegetation. Ash produced at low temperatures after low-severity burning is usually hydrophobic (Bodi et al., 2011, 2012). Wet-dry cycles have implications on ash physical and chemical properties, changing their effects in space and time. The aim of this study is to analyse the effects of fire temperature and severity on ash water repellency. Pinus sylvestris needles were collected in a Lithuania forest in Dzukija National Park (53º 54' N and 24º 22' E), transported to laboratory and washed with deionized water to remove soil particles and other residues. Needle samples were dried during 24 hours and exposed to different temperatures: 200, 300, 400 and 500 ºC, during 2 hours. Ash colour was analysed according to the Munsell Soil Color charts. Ash was black (10 YR 2/1) at 200 ºC, very dark grey (10YR 3/1) at 300 ºC, gray (10YR 5/1) at 400 ºC and light gray (10YR 7/1) at 500 ºC. Ten samples of ash released after each treatment were placed in plastic dishes (50 mm in diameter) in an amount enough to form a 5 mm thick layer, and ash water repellency was measured according to the Water Drop Penetration Test. Later, ash was carefully wetted with 15 ml of deionized water and placed in an oven during 4 days (96 hours), as in Bodí et al. (2012). This procedure was repeated 5 times in order to observe the effects of wet-dry cycles in ash water repellency. The results showed significant differences

  10. Wetting hysteresis induced by temperature changes: Supercooled water on hydrophobic surfaces.

    Science.gov (United States)

    Heydari, Golrokh; Sedighi Moghaddam, Maziar; Tuominen, Mikko; Fielden, Matthew; Haapanen, Janne; Mäkelä, Jyrki M; Claesson, Per M

    2016-04-15

    The state and stability of supercooled water on (super)hydrophobic surfaces is crucial for low temperature applications and it will affect anti-icing and de-icing properties. Surface characteristics such as topography and chemistry are expected to affect wetting hysteresis during temperature cycling experiments, and also the freezing delay of supercooled water. We utilized stochastically rough wood surfaces that were further modified to render them hydrophobic or superhydrophobic. Liquid flame spraying (LFS) was utilized to create a multi-scale roughness by depositing titanium dioxide nanoparticles. The coating was subsequently made non-polar by applying a thin plasma polymer layer. As flat reference samples modified silica surfaces with similar chemistries were utilized. With these substrates we test the hypothesis that superhydrophobic surfaces also should retard ice formation. Wetting hysteresis was evaluated using contact angle measurements during a freeze-thaw cycle from room temperature to freezing occurrence at -7°C, and then back to room temperature. Further, the delay in freezing of supercooled water droplets was studied at temperatures of -4°C and -7°C. The hysteresis in contact angle observed during a cooling-heating cycle is found to be small on flat hydrophobic surfaces. However, significant changes in contact angles during a cooling-heating cycle are observed on the rough surfaces, with a higher contact angle observed on cooling compared to during the subsequent heating. Condensation and subsequent frost formation at sub-zero temperatures induce the hysteresis. The freezing delay data show that the flat surface is more efficient in enhancing the freezing delay than the rougher surfaces, which can be rationalized considering heterogeneous nucleation theory. Thus, our data suggests that molecular flat surfaces, rather than rough superhydrophobic surfaces, are beneficial for retarding ice formation under conditions that allow condensation and frost

  11. An Engineered Anisotropic Nanofilm with Unidirectional Wetting Properties

    Science.gov (United States)

    2010-01-01

    to walk on water, butterflies to shed water from their wings and plants to trap insects and pollen . Capturing these natural features in biomimetic...butterfly wing water repellency3 and plant pollination4. In each case, such surfaces usually comprise millions of organized structures per square...MATERIALS | ADVANCE ONLINE PUBLICATION | www.nature.com/naturematerials 1 © 2010 Macmillan Publishers Limited. All rights reserved . Report Documentation

  12. Effect of wet vs. dry testing on the mechanical properties of hydrophilic self-etching primer polymers.

    Science.gov (United States)

    Hosaka, Keiichi; Tagami, Junji; Nishitani, Yoshihiro; Yoshiyama, Masahiro; Carrilho, Marcela; Tay, Franklin R; Agee, Kelli A; Pashley, David H

    2007-06-01

    Self-etching primers and adhesives contain very hydrophilic methacrylate monomers that result in high water sorptions by their polymers. Water sorption plasticizes the polymers and lowers their mechanical properties. The purpose of this work was to rank the hydrophilicity of a series of acidic primers by their Hoy's solubility parameters (delta) to determine if there was a significant relationship between the delta of polymers and their mechanical properties. A series of six acidic primer blends containing a fixed concentration of phenyl-P but variable amounts of 2-hydroxyethyl methacrylate (HEMA), 2,2 bi[4-(2-hydroxy-3-methacryloyloxy)propane (BisGMA), and triethylene-glycol dimethacrylate (TEGDMA) was formulated and their Hoy's solubility parameters calculated. The polymers were cast into small 'I' beams and light-cured. The modulus of elasticity (E) and ultimate tensile strength (UTS) were measured in dry polymers and after immersion in water for 24 h. The results showed significant correlations between E and UTS under dry or wet conditions. Both E and UTS fell significantly when the specimens were immersed in water. After water immersion, the E and UTS showed significant correlations with Hoy's delta(p) values. Both E and UTS correlated significantly with the BisGMA concentration of the polymers, either wet or dry. The percentage changes in E or UTS were significantly correlated with the water sorption of the polymers.

  13. The Analysis of Four Waters Converting Mechanism in Wet and Low-lying Farmland

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhong-xue; WEI Yong-xia; KANG Bai-ying

    2004-01-01

    Most of China's wetland areas are located in Sanjiang Plain (Three River Basin). It's area has 207×104 hm2 of wet and low-lying farmland, of which 59% is cropped. During 1970s and 1980s, the Chinese government organized intensive scientific research into potential changes to existing natural resources conditions for this farmland.The aim was to make the water resources regime beneficial to crop production. Arterial drainage, field drainage and appropriate sub-soil treatments were suggested. The Four Waters converting mechanism and the estimation of the Four Water converting amount in wet and low-lying farmland were discussed in the paper.

  14. Wetting and absorption of water drops on Nafion films.

    Science.gov (United States)

    Goswami, Sharonmoyee; Klaus, Shannon; Benziger, Jay

    2008-08-19

    Water drops on Nafion films caused the surface to switch from being hydrophobic to being hydrophilic. Contact angle hysteresis of >70 degrees between advancing and receding values were obtained by the Wilhelmy plate technique. Sessile drop measurements were consistent with the advancing contact angle; the sessile drop contact angle was 108 degrees . Water drop adhesion, as measured by the detachment angle on an inclined plane, showed much stronger water adhesion on Nafion than Teflon. Sessile water and methanol drops caused dry Nafion films to deflect. The flexure went through a maximum with time. Flexure increased with contact area of the drop, but was insensitive to the film thickness. Methanol drops spread more on Nafion and caused larger film flexure than water. The results suggest that the Nafion surface was initially hydrophobic but water and methanol drops caused hydrophilic sulfonic acid domains to be drawn to the Nafion surface. Local swelling of the film beneath the water drop caused the film to buckle. The maximum flexure is suggested to result from motion of a water swelling front through the Nafion film.

  15. WET-tests on UV-treated ballast water

    NARCIS (Netherlands)

    Kaag, N.H.B.M.

    2015-01-01

    Damen Shipyards has developed a barge-based ballast water management system (BWMS) that enables direct treatment of ballast water during discharge in a receiving harbour. The treatment is based upon filtration and a once-through UV-treatment. As part of the Type Approval process, the Dutch Authoriti

  16. Water-induced finger wrinkles do not affect touch acuity or dexterity in handling wet objects.

    Directory of Open Access Journals (Sweden)

    Julia Haseleu

    Full Text Available Human non-hairy (glabrous skin of the fingers, palms and soles wrinkles after prolonged exposure to water. Wrinkling is a sympathetic nervous system-dependent process but little is known about the physiology and potential functions of water-induced skin wrinkling. Here we investigated the idea that wrinkling might improve handling of wet objects by measuring the performance of a large cohort of human subjects (n = 40 in a manual dexterity task. We also tested the idea that skin wrinkling has an impact on tactile acuity or vibrotactile sensation using two independent sensory tasks. We found that skin wrinkling did not improve dexterity in handling wet objects nor did it affect any aspect of touch sensitivity measured. Thus water-induced wrinkling appears to have no significant impact on tactile driven performance or dexterity in handling wet or dry objects.

  17. Spacecraft Water Regeneration by Catalytic Wet Air Oxidation Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this project is to develop advanced catalysts for a volatile removal assembly used to purify spacecraft water. The innovation of the proposed...

  18. Properties of fly ashes in wet environment; Flygaskors egenskaper i vaat miljoe

    Energy Technology Data Exchange (ETDEWEB)

    Broemssen, M. von; Lindstroem, N.; Hedman, K.; Svensson, M.

    2009-03-15

    This report describes how inorganic elements are mobilised from fly ashes that are placed under water, i.e. what are the properties and processes that governs the mobilisation. This knowledge may serve as basic data for decision making when fly ashes from e.g. bio-, industrial- and municipal solid wastes are to be used in civil engineering applications in wet environments. The composition of ashes varies in a vide range of concentrations and depends on the fuel and the type of incinerator. The main contents of fly ashes are calcium oxide, silicic acid and aluminium compounds. Several environmental hazardous elements are also present in varying concentrations. The pH of fishily is often very high. A number of chemical processes occur when flyashes is mixed with water. When the pH-value increases, mainly due to hydratisation of calcium oxide (CaO), many metals will precipitate as metal hydroxides. The objective of this study was to, within a rather short time period (8 month), describe the processes governing mobilisation of different elements from fly ashes placed under water. The work included chemical equilibrium modelling with PHREEQC, the model was used to determine what minerals may control solubility of different elements. Three fly ashes were used for the study, one flyash from industrial- and municipal waste with no CaO or ammonia added, one flyash from municipal waste with CaO and ammonia added and one fly ash from solid biofuels with chalk added. The fly ashes, ca 300 kg, was mixed with water in 1000 l plastic containers and filled with water. Two batches per flyash were used; i) in the first batch surplus water were not replaced, ii) in the second batch the surplus water was replaced with fresh water five times during the test. Measured pH-values in the batches with industrial and municipal waste were stabilised at a pH-value around 9.5 indicating carbonation is complete. The pH-values in the bio flyash were higher. Four categories of elements were

  19. Study on wetting properties of periodical nanopatterns by a combinative technique of photolithography and laser interference lithography

    KAUST Repository

    Yang, Yung-Lang

    2010-03-01

    This study presents the wetting properties, including hydrophilicity, hydrophobicity and anisotropic behavior, of water droplets on the silicon wafer surface with periodical nanopatterns and hierarchical structures. This study fabricates one- and two-dimensional periodical nanopatterns using laser interference lithography (LIL). The fabrication of hierarchical structures was effectively achieved by combining photolithography and LIL techniques. Unlike conventional fabrication methods, the LIL technique is mainly used to control the large-area design of periodical nanopatterns in this study. The minimum feature size for each nanopattern is 100 nm. This study shows that the wetting behavior of one-dimensional, two-dimensional, and hierarchical patterns can be obtained, benefiting the development of surface engineering for microfluidic systems. © 2010 Elsevier B.V. All rights reserved.

  20. Mapping soil water dynamics and a moving wetting front by spatiotemporal inversion of electromagnetic induction data

    Science.gov (United States)

    Huang, J.; Monteiro Santos, F. A.; Triantafilis, J.

    2016-11-01

    Characterization of the spatiotemporal distribution of soil volumetric water content (θ) is fundamental to agriculture, ecology, and earth science. Given the labor intensive and inefficient nature of determining θ, apparent electrical conductivity (ECa) measured by electromagnetic induction has been used as a proxy. A number of previous studies have employed inversion algorithms to convert ECa data to depth-specific electrical conductivity (σ) which could then be correlated to soil θ and other soil properties. The purpose of this study was to develop a spatiotemporal inversion algorithm which accounts for the temporal continuity of ECa. The algorithm was applied to a case study where time-lapse ECa was collected on a 350 m transect on seven different days on an alfalfa farm in the USA. Results showed that the approach was able to map the location of moving wetting front along the transect. Results also showed that the spatiotemporal inversion algorithm was more precise (RMSE = 0.0457 cm3/cm3) and less biased (ME = -0.0023 cm3/cm3) as compared with the nonspatiotemporal inversion approach (0.0483 cm3/cm3 and ME = -0.0030 cm3/cm3, respectively). In addition, the spatiotemporal inversion algorithm allows for a reduced set of ECa surveys to be used when non abrupt changes of soil water content occur with time. To apply this spatiotemporal inversion algorithm beyond low induction number condition, full solution of the EM induction phenomena can be studied in the future.

  1. Stay Wet, Stay Stable? How Internal Water Helps the Stability of Thermophilic Proteins.

    Science.gov (United States)

    Chakraborty, Debashree; Taly, Antoine; Sterpone, Fabio

    2015-10-08

    We present a systematic computational investigation of the internal hydration of a set of homologous proteins of different stability content and molecular complexities. The goal of the study is to verify whether structural water can be part of the molecular mechanisms ensuring enhanced stability in thermophilic enzymes. Our free-energy calculations show that internal hydration in the thermophilic variants is generally more favorable, and that the cumulated effect of wetting multiple sites results in a meaningful contribution to stability. Moreover, thanks to a more effective capability to retain internal water, some thermophilic proteins benefit by a systematic gain from internal wetting up to their optimal working temperature. Our work supports the idea that internal wetting can be viewed as an alternative molecular variable to be tuned for increasing protein stability.

  2. Stay Wet, Stay Stable? How Internal Water Helps Stability of Thermophilic Proteins

    Science.gov (United States)

    Chakraborty, Debashree; Taly, Antoine; Sterpone, Fabio

    2017-01-01

    We present a systematic computational investigation of the internal hydration of a set of homologous proteins of different stability content and molecular complexities. The goal of the study is to verify whether structural water can be part of the molecular mechanisms ensuring enhanced stability in thermophilic enzymes. Our free energy calculations show that internal hydration in the thermophilic variants is generally more favourable and that the cumulated effect of wetting multiple sites results in a meaningful contribution to stability. Moreover, thanks to a more effective capability to retain internal water some thermophilic proteins benefit of a systematic gain from internal wetting up to their optimal working temperature. Our work supports the idea that internal wetting can be viewed as an alternative molecular variable to be tuned for increasing protein stability. PMID:26335353

  3. Characterization of Polymer Surfaces by the Use of Different Wetting Theories Regarding Acid-Base Properties

    Directory of Open Access Journals (Sweden)

    Eduard Kraus

    2017-01-01

    Full Text Available The existing wetting methods for the determination of acid-base properties on solid surfaces are discussed. Striving for a better understanding of the adhesive polymer interactions in adhesively joined polymers, the methods of Berger and van Oss-Chaudhury-Good were found as the most suitable methods for the investigation of wetting on solid polymer surfaces. Methods of nonlinear systems by Della Volpe and Siboni were adapted and evaluated on plastic surfaces. In the context of these investigations various data of the surface free energy as well as its components have been identified for a number of polymer surfaces by application of spatial equation solutions.

  4. Superhydrophobic aluminium-based surfaces: Wetting and wear properties of different CVD-generated coating types

    Science.gov (United States)

    Thieme, M.; Streller, F.; Simon, F.; Frenzel, R.; White, A. J.

    2013-10-01

    In view of generating superhydrophobic aluminium-based surfaces, this work presents further results for the combination of anodic oxidation as the primary pretreatment method and chemical vapour deposition (CVD) variants for chemical modification producing coatings of 250-1000 nm thickness. In detail, CVD involved the utilisation of i - hexafluoropropylene oxide as precursor within the hot filament CVD process for the deposition of poly(tetrafluoroethylene) coatings at alternative conditions (PTFE-AC) and ii - 1,3,5-trivinyltrimethylcyclotrisiloxane for the deposition of polysiloxane coatings (PSi) by initiated CVD. The substrate material was Al Mg1 subjected to usual or intensified sulphuric acid anodisation pretreatments (SAAu, SAAi, respectively) affording various degrees of surface micro-roughness (SAAu weathering and/or mild wear testing. Superhydrophobicity (SH) was observed with the system SAAi + PTFE-AC similarly to former findings with the standard hot filament CVD PTFE coating variant (SAAi + PTFE-SC). The results indicated that the specific coating morphology made an important contribution to the water-repellency, because even some of the SAAu-based samples tended to reveal SH. Subjecting samples to weathering treatment resulted in a general worsening of the wetting behaviour, primarily limited to the receding contact angles. These tendencies were correlated with the chemical composition of the sample surfaces as analysed by X-ray photoelectron spectroscopy. The wear tests showed, as evaluated by scanning electron microscopy and contact angle measurement, that the PTFE coatings were relatively sensitive to friction. This was connected with a dramatic deterioration of the water-repelling properties. PSi-coated surfaces generally showed rather poor water-repellency, but this coating type was surprisingly resistant towards the applied friction test. From these findings it may be concluded that the combination of hydrophobic fluorine containing structure

  5. Using liquid droplet penetration experiments to determine wetting properties of powders

    Science.gov (United States)

    Callegari, Gerardo; Liu, Zhanjie; Wang, Yifan; Muzzio, Fernando; Drazer, German

    2016-11-01

    We show that the spontaneous penetration of droplets on a powder bed provides a simple way to characterize the wetting properties of a test liquid. Specifically, we demonstrate that calculating the appropriate dimensionless penetrating volume and time, and performing supplementary experiments with a reference liquid, it is possible to obtain the contact angle between the test liquid and the powder. Interestingly, the proposed analysis lets us calculate the contact angle without having to compute the solution to the 3D penetration problem. This approach is valid when the contact area between the droplet and the powder bed remains constant, which is a good approximation in many powder systems. We first test the validity of our approach by studying droplets of different sizes and show that the non-dimensional penetration curves are independent of the initial volume and contact radius of the drops, as predicted. We then use a reference liquid (silicone oil) to measure the contact angle of water on three powder systems with increasing number of pharmaceutical components and different processing conditions known to affect blend wettability. We show that the proposed method is able to capture the overlubrication of the blend, a well-known effect in pharmaceutical manufacturing.

  6. Evaporation-Triggered Wetting Transition for Water Droplets upon Hydrophobic Microstructures

    OpenAIRE

    Tsai, Peichun; Lammertink, Rob G. H.; Wessling, Matthias; Lohse, Detlef

    2010-01-01

    When placed on rough hydrophobic surfaces, water droplets of diameter larger than a few millimeters can easily form pearls, as they are in the Cassie-Baxter state with air pockets trapped underneath the droplet. Intriguingly, a natural evaporating process can drive such a Fakir drop into a completely wetting (Wenzel) state. Our microscopic observations with simultaneous side and bottom views of evaporating droplets upon transparent hydrophobic microstructures elucidate the water-filling dynam...

  7. Wetting of sessile water drop under an external electrical field

    Science.gov (United States)

    Vancauwenberghe, Valerie; di Marco, Paolo; Brutin, David; Amu Collaboration; Unipi Collaboration

    2013-11-01

    The enhancement of heat and mass transfer using a static electric field is an interesting process for industrial applications, due to its low energy consumption and potentially high level of evaporation rate enhancement. However, to date, this phenomenon is still not understood in the context of the evaporation of sessile drops. We previously synthesized the state of the art concerning the effect of an electric field on sessile drops with a focus on the change of contact angle and shape and the influence of the evaporation rate [1]. We present here the preliminary results of an new experiment set-up. The novelty of the set-up is the drop injection from the bottom that allows to generate safety the droplet under the electrostatic field. The evaporation at room temperature of water drops having three different volumes has been investigated under an electric field up to 10.5 kV/cm. The time evolutions of the contact angles, volumes and diameters have been analysed. As reported in the literature, the drop elongate along the direction of the electric field. Despite the hysteresis effect of the contact angle, the receding contact angle increases with the strength of the electric field. This is clearly observable for the small drops for which the gravity effect can be neglected.

  8. Measurement of wetted area fraction in subcooled pool boiling of water using infrared thermography

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyungdae, E-mail: hdkims@khu.ac.kr [Massachusetts Institute of Technology, Cambridge, Massachusetts (United States); Kyung Hee University, Youngin, Gyeonggi 446-701 (Korea, Republic of); Park, Youngjae [Kyung Hee University, Youngin, Gyeonggi 446-701 (Korea, Republic of); Buongiorno, Jacopo, E-mail: jacopo@mit.edu [Massachusetts Institute of Technology, Cambridge, Massachusetts (United States)

    2013-11-15

    The wetted area fraction in subcooled pool boiling of water at atmospheric pressure is measured using the DEPIcT (DEtection of Phase by Infrared Thermography) technique. DEPIcT exploits the contrast in infrared (IR) light emissions between wet and dry areas on the surface of an IR-transparent heater to visualize the instantaneous distribution of the liquid and gas phases in contact with the heater surface. In this paper time-averaged wetted area fraction data in nucleate boiling are reported as functions of heat flux (from 30% up to 100% of the Critical Heat Flux) and subcooling (ΔT{sub sub} = 0, 5, 10, 30 and 50 °C). The results show that the wetted area fraction monotonically decreases with increasing heat flux and increases with increasing subcooling: both trends are expected. The range of time-averaged wetted area fractions is from 90%, at low heat flux and high subcooling, to 50% at high heat flux (right before CHF) and low subcooling. It is also shown that the dry areas are periodically rewetted by liquid sloshing on the surface at any subcooling and heat flux; however, the dry areas expand irreversibly at CHF.

  9. Depletion of water molecules during ethanol wet-bonding with etch and rinse dental adhesives

    Energy Technology Data Exchange (ETDEWEB)

    Gregoire, Genevieve, E-mail: gregoire@cict.fr [Department of Biomaterials, Faculty of Odontology, University Toulouse III, 31062, Toulouse (France); Sharrock, Patrick [Medical and Spatial Imaging Laboratory, University Toulouse III, Ave. Pompidou, 81104, Castres (France); Delannee, Mathieu [Department of Biomaterials, Faculty of Odontology, University Toulouse III, 31062, Toulouse (France); Delisle, Marie-Bernadette [Faculty of Medicine, University Toulouse III, 31062, Toulouse (France)

    2013-01-01

    The treatment of demineralized dentin with ethanol has been proposed as a way to improve hydrophobic monomer penetration into otherwise water saturated collagen fibrils. The ethanol rinse is expected to preserve the fibrils from collapsing while optimizing resin constituent infiltration for better long term adhesion. The physico-chemical investigations of demineralized dentin confirmed objectively these working hypotheses. Namely, Differential Scanning Calorimetry (DSC) measurements of the melting point of water molecules pointed to the presence of free and bound water states. Unfreezable water was the main type of water remaining following a rinsing step with absolute ethanol. Two different liquid water phases were also observed by Magic Angle Spinning (MAS) solid state Nuclear magnetic Resonance (NMR) spectroscopy. Infrared spectra of ethanol treated specimens illustrated differences with the fully hydrated specimens concerning the polar carbonyl vibrations. Optical microscopy observations as well as scanning electron microscopy showed an improved dentin-adhesive interface with ethanol wet bonding. The results indicate that water can be confined to strongly bound structural molecules when excess water is removed with ethanol prior to adhesive application. This should preserve collagen from hydrolysis upon aging of the hybrid layer. - Highlights: Black-Right-Pointing-Pointer Non-freezable water exists in demineralized dentine. Black-Right-Pointing-Pointer Free water can be removed by ethanol rinse of the demineralized collagen. Black-Right-Pointing-Pointer Ethanol wet bonding leads to a homogeneous hybrid layer free of defects.

  10. Evaporation-triggered wetting transition for water droplets upon hydrophobic microstructures.

    Science.gov (United States)

    Tsai, Peichun; Lammertink, Rob G H; Wessling, Matthias; Lohse, Detlef

    2010-03-19

    When placed on rough hydrophobic surfaces, water droplets of diameter larger than a few millimeters can easily form pearls, as they are in the Cassie-Baxter state with air pockets trapped underneath the droplet. Intriguingly, a natural evaporating process can drive such a Fakir drop into a completely wetting (Wenzel) state. Our microscopic observations with simultaneous side and bottom views of evaporating droplets upon transparent hydrophobic microstructures elucidate the water-filling dynamics and suggest the mechanism of this evaporation-triggered transition. For the present material the wetting transition occurs when the water droplet size decreases to a few hundreds of micrometers in radius. We present a general global energy argument which estimates the interfacial energies depending on the drop size and can account for the critical radius for the transition.

  11. Effects of Dry-Milling and Wet-Milling on Chemical, Physical and Gelatinization Properties of Rice Flour

    Directory of Open Access Journals (Sweden)

    Jitranut Leewatchararongjaroen

    2016-09-01

    Full Text Available Rice flour from nine varieties, subjected to dry- and wet-milling processes, was determined for its physical and chemical properties. The results revealed that milling method had an effect on properties of flour. Wet-milling process resulted in flour with significantly lower protein and ash contents and higher carbohydrate content. Wet-milled flour also tended to have lower lipid content and higher amylose content. In addition, wet-milled rice flour contained granules with smaller average size compared to dry-milled samples. Swelling power at 90 °C of wet-milled samples was higher while solubility was significantly lower than those of dry-milled flour. Dry milling process caused the destruction of the crystalline structure and yielded flour with lower crystallinity compared to wet-milling process, which resulted in significantly lower gelatinization enthalpy.

  12. Molecular dynamics simulations of wetting behavior of water droplets on polytetrafluorethylene surfaces.

    Science.gov (United States)

    Chen, Shuai; Wang, Jiadao; Ma, Tianbao; Chen, Darong

    2014-03-21

    Molecular dynamics simulations are performed to simulate the wetting behavior of nanosized water droplets on flat and pillar polytetrafluorethylene surfaces. The results show that the cutoff of the Lennard-Jones (LJ) potential has a large effect on the simulated value of the contact angle and some suggestions are given on how to choose an appropriate cutoff. On flat surfaces, the contact angle is independent of the size of the water droplet, which was determined by the energy parameters of the LJ potential. Furthermore, on pillar surfaces, two different equilibrium states are present: wetted contact and cross contact. For the wetted contact state, the contact angle increases with increasing droplet size and pillar size within a certain range. However, for the cross contact state, the contact angle and droplet size are uncorrelated, which results from the layering and structuring of molecules after their penetration into the hollows between pillars. However, additional simulations show that the final state depends on the initial geometry and the cross contact state is a metastable wetting state.

  13. Nano-Wilhelmy investigation of dynamic wetting properties of AFM tips through tip-nanobubble interaction.

    Science.gov (United States)

    Wang, Yuliang; Wang, Huimin; Bi, Shusheng; Guo, Bin

    2016-07-25

    The dynamic wetting properties of atomic force microscopy (AFM) tips are of much concern in many AFM-related measurement, fabrication, and manipulation applications. In this study, the wetting properties of silicon and silicon nitride AFM tips are investigated through dynamic contact angle measurement using a nano-Wilhelmy balance based method. This is done by capillary force measurement during extension and retraction motion of AFM tips relative to interfacial nanobubbles. The working principle of the proposed method and mathematic models for dynamic contact angle measurement are presented. Geometric models of AFM tips were constructed using scanning electronic microscopy (SEM) images taken from different view directions. The detailed process of tip-nanobubble interaction was investigated using force-distance curves of AFM on nanobubbles. Several parameters including nanobubble height, adhesion and capillary force between tip and nanobubbles are extracted. The variation of these parameters was studied over nanobubble surfaces. The dynamic contact angles of the AFM tips were calculated from the capillary force measurements. The proposed method provides direct measurement of dynamic contact angles for AFM tips and can also be taken as a general approach for nanoscale dynamic wetting property investigation.

  14. Improving methane storage on wet activated carbons at various amounts of water

    Institute of Scientific and Technical Information of China (English)

    MOHAMMAD JABER DARABI MAHBOUB; ALI AHMADPOUR; HAMED RASHIDI

    2012-01-01

    Different mesoporous activated carbons were prepared by both chemical and physical activation processes and were examined for methane uptake in the presence of water.Methane isotherms were obtained at wet condition by wetting samples with water at mass ratio of water/carbon (R) close to 1.0.To compare,the amount of methane storage were also measured at dry situation.The maximum amount of methane stored was attained as 237 WV at R=1.0 by hydrate formation at the methane critical pressure.In the next step,mass ratios of water/carbon were changed to investigate various amount of water for methane storage enhancement.Two other values of mass ratio of water/carbon ( R =0.8 and 1.4 ) were selected and methane isotherms were obtained at the same conditions.Maximum values of 210 and 248 V/V were reached for methane storage,respectively.It was also observed that,in the pressure range lower than hydrate pressure,by increasing water ratio the hydrate formation pressure was decreased and methane uptake was much less than that of dry condition due to pore filling by water.

  15. An analytical method for 14C in environmental water based on a wet-oxidation process.

    Science.gov (United States)

    Huang, Yan-Jun; Guo, Gui-Yin; Wu, Lian-Sheng; Zhang, Bing; Chen, Chao-Feng; Zhang, Hai-Ying; Qin, Hong-Juan; Shang-Guan, Zhi-Hong

    2015-04-01

    An analytical method for (14)C in environmental water based on a wet-oxidation process was developed. The method can be used to determine the activity concentrations of organic and inorganic (14)C in environmental water, or total (14)C, including in drinking water, surface water, rainwater and seawater. The wet-oxidation of the organic component allows the conversion of organic carbon to an inorganic form, and the extraction of the inorganic (14)C can be achieved by acidification and nitrogen purging. Environmental water with a volume of 20 L can be used for the wet-oxidation and extraction, and a detection limit of about 0.02 Bq/g(C) can be achieved for water with carbon content above 15 mg(C)/L, obviously lower than the natural level of (14)C in the environment. The collected carbon is sufficient for measurement with a low level liquid scintillation counter (LSC) for typical samples. Extraction or recovery experiments for inorganic carbon and organic carbon from typical materials, including analytical reagents of organic benzoquinone, sucrose, glutamic acid, nicotinic acid, humic acid, ethane diol, et cetera., were conducted with excellent results based on measurement on a total organic carbon analyzer and LSC. The recovery rate for inorganic carbon ranged tween 98.7%-99.0% with a mean of 98.9(± 0.1)%, for organic carbon recovery ranged between 93.8% and 100.0% with a mean of 97.1(± 2.6)%. Verification and an uncertainty budget of the method are also presented for a representative environmental water. The method is appropriate for (14)C analysis in environmental water, and can be applied also to the analysis of liquid effluent from nuclear facilities.

  16. Water and Ethanol Droplet Wetting Transition during Evaporation on Omniphobic Surfaces

    Science.gov (United States)

    Chen, Xuemei; Weibel, Justin A.; Garimella, Suresh V.

    2015-11-01

    Omniphobic surfaces with reentrant microstructures have been investigated for a range of applications, but the evaporation of high- and low-surface-tension liquid droplets placed on such surfaces has not been rigorously studied. In this work, we develop a technique to fabricate omniphobic surfaces on copper substrates to allow for a systematic examination of the effects of surface topography on the evaporation dynamics of water and ethanol droplets. Compared to a water droplet, the ethanol droplet not only evaporates faster, but also inhibits Cassie-to-Wenzel wetting transitions on surfaces with certain geometries. We use an interfacial energy-based description of the system, including the transition energy barrier and triple line energy, to explain the underlying transition mechanism and behaviour observed. Suppression of the wetting transition during evaporation of droplets provides an important metric for evaluating the robustness of omniphobic surfaces requiring such functionality.

  17. Stay Wet, Stay Stable? How Internal Water Helps Stability of Thermophilic Proteins

    OpenAIRE

    Chakraborty, Debashree; Taly, Antoine; Sterpone, Fabio

    2015-01-01

    We present a systematic computational investigation of the internal hydration of a set of homologous proteins of different stability content and molecular complexities. The goal of the study is to verify whether structural water can be part of the molecular mechanisms ensuring enhanced stability in thermophilic enzymes. Our free energy calculations show that internal hydration in the thermophilic variants is generally more favourable and that the cumulated effect of wetting multiple sites res...

  18. Superhydrophobic aluminium-based surfaces: Wetting and wear properties of different CVD-generated coating types

    Energy Technology Data Exchange (ETDEWEB)

    Thieme, M., E-mail: michael.thieme@tu-dresden.de [Technische Universität Dresden, Institute of Materials Science, 01062 Dresden (Germany); Streller, F., E-mail: streller@seas.upenn.edu [Technische Universität Dresden, Institute of Materials Science, 01062 Dresden (Germany); Simon, F., E-mail: frsimon@ipfdd.de [Leibniz-Institut für Polymerforschung Dresden, Postfach 120 411, 01005 Dresden (Germany); Frenzel, R., E-mail: frenzelr@ipfdd.de [Leibniz-Institut für Polymerforschung Dresden, Postfach 120 411, 01005 Dresden (Germany); White, A.J. [GVD Corporation, 45 Spinelli Place, Cambridge, MA 02138 (United States)

    2013-10-15

    In view of generating superhydrophobic aluminium-based surfaces, this work presents further results for the combination of anodic oxidation as the primary pretreatment method and chemical vapour deposition (CVD) variants for chemical modification producing coatings of 250–1000 nm thickness. In detail, CVD involved the utilisation of i – hexafluoropropylene oxide as precursor within the hot filament CVD process for the deposition of poly(tetrafluoroethylene) coatings at alternative conditions (PTFE-AC) and ii – 1,3,5-trivinyltrimethylcyclotrisiloxane for the deposition of polysiloxane coatings (PSi) by initiated CVD. The substrate material was Al Mg1 subjected to usual or intensified sulphuric acid anodisation pretreatments (SAAu, SAAi, respectively) affording various degrees of surface micro-roughness (SAAu < SAAi) to the oxidic layers. Performance characteristics were evaluated in the original as-coated states and after standardised artificial weathering and/or mild wear testing. Superhydrophobicity (SH) was observed with the system SAAi + PTFE-AC similarly to former findings with the standard hot filament CVD PTFE coating variant (SAAi + PTFE-SC). The results indicated that the specific coating morphology made an important contribution to the water-repellency, because even some of the SAAu-based samples tended to reveal SH. Subjecting samples to weathering treatment resulted in a general worsening of the wetting behaviour, primarily limited to the receding contact angles. These tendencies were correlated with the chemical composition of the sample surfaces as analysed by X-ray photoelectron spectroscopy. The wear tests showed, as evaluated by scanning electron microscopy and contact angle measurement, that the PTFE coatings were relatively sensitive to friction. This was connected with a dramatic deterioration of the water-repelling properties. PSi-coated surfaces generally showed rather poor water-repellency, but this coating type was surprisingly

  19. Titanium carbide nanoparticles reinforcing nickel matrix for improving nanohardness and fretting wear properties in wet conditions

    Science.gov (United States)

    Dănăilă, Eliza; Benea, Lidia; Caron, Nadège; Raquet, Olivier

    2016-09-01

    In this study Ni/nano-TiC functional composite coatings were produced by electro-codeposition of TiC nanoparticles (50 nm mean diameter) with nickel on 304L stainless steel support. Coatings were obtained from a Watts classical solution in which TiC nanoparticles were added. The surface morphology, chemical composition, structure, roughness and thickness, were evaluated in relation to the effect of TiC nanoparticles incorporation into Ni matrix. It was found that incorporation of TiC nanoparticles into the nickel matrix produces morphological changes in the deposit and increases the roughness. The fretting wear behavior in wet conditions of the obtained coatings was evaluated on a ball-on-plate configuration. To evaluate the wet fretting wear (tribocorrosion) behavior the open circuit potential was measured before, during and after the fretting tests at room temperature in the solution that simulates the primary water circuit of Pressurized Water Reactors. The results show that Ni/nano-TiC composite coatings exhibited a low friction coefficient, high nanohardness and fretting wear resistance in wet conditions compared with pure Ni coatings.

  20. Gray free-energy multiphase lattice Boltzmann model with effective transport and wetting properties.

    Science.gov (United States)

    Zalzale, Mohamad; Ramaioli, M; Scrivener, K L; McDonald, P J

    2016-11-01

    The paper shows that it is possible to combine the free-energy lattice Boltzmann approach to multiphase modeling of fluids involving both liquid and vapor with the partial bounce back lattice Boltzmann approach to modeling effective media. Effective media models are designed to mimic the properties of porous materials with porosity much finer than the scale of the simulation lattice. In the partial bounce-back approach, an effective media parameter or bounce-back fraction controls fluid transport. In the combined model, a wetting potential is additionally introduced that controls the wetting properties of the fluid with respect to interfaces between free space (white nodes), effective media (gray nodes), and solids (black nodes). The use of the wetting potential combined with the bounce-back parameter gives the model the ability to simulate transport and sorption of a wide range of fluid in material systems. Results for phase separation, permeability, contact angle, and wicking in gray media are shown. Sorption is explored in small sections of model multiscale porous systems to demonstrate two-step desorption, sorption hysteresis, and the ink-bottle effect.

  1. Gray free-energy multiphase lattice Boltzmann model with effective transport and wetting properties

    Science.gov (United States)

    Zalzale, Mohamad; Ramaioli, M.; Scrivener, K. L.; McDonald, P. J.

    2016-11-01

    The paper shows that it is possible to combine the free-energy lattice Boltzmann approach to multiphase modeling of fluids involving both liquid and vapor with the partial bounce back lattice Boltzmann approach to modeling effective media. Effective media models are designed to mimic the properties of porous materials with porosity much finer than the scale of the simulation lattice. In the partial bounce-back approach, an effective media parameter or bounce-back fraction controls fluid transport. In the combined model, a wetting potential is additionally introduced that controls the wetting properties of the fluid with respect to interfaces between free space (white nodes), effective media (gray nodes), and solids (black nodes). The use of the wetting potential combined with the bounce-back parameter gives the model the ability to simulate transport and sorption of a wide range of fluid in material systems. Results for phase separation, permeability, contact angle, and wicking in gray media are shown. Sorption is explored in small sections of model multiscale porous systems to demonstrate two-step desorption, sorption hysteresis, and the ink-bottle effect.

  2. Investigation of Parameters Affecting Gypsum Dewatering Properties in a Wet Flue Gas Desulphurization Pilot Plant

    DEFF Research Database (Denmark)

    Hansen, Brian Brun; Kiil, Søren

    2012-01-01

    Wet flue gas desulphurization (FGD) plants with forced oxidation, installed at coal and oil fired power plants for removal of SO2(g), must produce gypsum of high quality. However, quality issues such as an excessive moisture content, due to poor gypsum dewatering properties, may occur from time...... to time. In this work, the particle size distribution, morphology, and filtration rate of wet FGD gypsum formed in a pilot-scale experimental setup, operated in forced oxidation mode, have been studied. The influence of holding tank residence time (10–408 h), solids content (30–169 g/L), and the presence...... of impurities (0.002 M Al2F6; 50 g quartz/L; 0.02 M Al3+, and 0.040 M Mg2+) were investigated. In addition, slurry from a full-scale wet FGD plant, experiencing formation of flat shaped crystals and poor gypsum dewatering properties, was transferred to the pilot plant to test if the plant would now start...

  3. Water Use Efficiency and Physiological Response of Rice Cultivars under Alternate Wetting and Drying Conditions

    Directory of Open Access Journals (Sweden)

    Yunbo Zhang

    2012-01-01

    Full Text Available One of the technology options that can help farmers cope with water scarcity at the field level is alternate wetting and drying (AWD. Limited information is available on the varietal responses to nitrogen, AWD, and their interactions. Field experiments were conducted at the International Rice Research Institute (IRRI farm in 2009 dry season (DS, 2009 wet season (WS, and 2010 DS to determine genotypic responses and water use efficiency of rice under two N rates and two water management treatments. Grain yield was not significantly different between AWD and continuous flooding (CF across the three seasons. Interactive effects among variety, water management, and N rate were not significant. The high yield was attributed to the significantly higher grain weight, which in turn was due to slower grain filling and high leaf N at the later stage of grain filling of CF. AWD treatments accelerated the grain filling rate, shortened grain filling period, and enhanced whole plant senescence. Under normal dry-season conditions, such as 2010 DS, AWD reduced water input by 24.5% than CF; however, it decreased grain yield by 6.9% due to accelerated leaf senescence. The study indicates that proper water management greatly contributes to grain yield in the late stage of grain filling, and it is critical for safe AWD technology.

  4. Effects of Wet/Dry-Cycling and Plasma Treatments on the Properties of Flax Nonwovens Intended for Composite Reinforcing

    Directory of Open Access Journals (Sweden)

    Heura Ventura

    2016-02-01

    Full Text Available This research analyzes the effects of different treatments on flax nonwoven (NW fabrics which are intended for composite reinforcement. The treatments applied were of two different kinds: a wet/dry cycling which helps to stabilize the cellulosic fibers against humidity changes and plasma treatments with air, argon and ethylene gases considering different conditions and combinations, which produce variation on the chemical surface composition of the NWs. The resulting changes in the chemical surface composition, wetting properties, thermal stability and mechanical properties were determined. Variations in surface morphology could be observed by scanning electron microscopy (SEM. The results of the X-ray photoelectron spectroscopy (XPS showed significant changes to the surface chemistry for the samples treated with argon or air (with more content on polar groups on the surface and ethylene plasma (with less content of polar groups. Although only slight differences were found in moisture regain and water retention values (WRV, significant changes were found on the contact angle values, thus revealing hydrophilicity for the air-treated and argon-treated samples and hydrophobicity for the ethylene-treated ones. Moreover, for some of the treatments the mechanical testing revealed an increase of the NW breaking force.

  5. Ultra-wetting graphene-based PES ultrafiltration membrane - A novel approach for successful oil-water separation.

    Science.gov (United States)

    Prince, J A; Bhuvana, S; Anbharasi, V; Ayyanar, N; Boodhoo, K V K; Singh, G

    2016-10-15

    Oil pollution in water and separation of oil from water are receiving much attention in recent years due to the growing environmental concerns. Membrane technology is one of the emerging solutions for oil-water separation. However, there is a limitation in using polymeric membrane for oil water separation due to its surface properties (wetting behaviour), thermal and mechanical properties. Here, we have shown a simple method to increase the hydrophilicity of the polyethersulfone (PES) hollow fibre ultrafiltration (UF) membrane by using carboxyl, hydroxyl and amine modified graphene attached poly acrylonitrile-co-maleimide (G-PANCMI). The prepared membranes were characterized for its morphology, water and oil contact angle, liquid entry pressure of oil (LEPoil), water permeability and finally subjected to a continuous 8 h filtration test of oil emulsion in water. The experimental data indicates that the G-PANCMI play an important role in enhancing the hydrophilicity, permeability and selectivity of the PES membrane. The water contact angle (CAw) of the PES membrane is reduced from 63.7 ± 3.8° to 22.6 ± 2.5° which is 64.5% reduction while, the oil contact angle was increased from 43.6 ± 3.5° to 112.5 ± 3.2° which is 158% higher compared to that of the PES membrane. Similarly, the LEPoil increased 350% from 50 ± 10 kPa of the control PES membrane to 175 ± 25 kPa of PES-G-PANCMI membrane. More importantly, the water permeability increased by 43% with >99% selectivity. Based on our findings we believe that the development of PES-G-PANCMI membrane will open up a solution for successful oil-water separation.

  6. Spatial and temporal mapping of water content across Nafion membranes under wetting and drying conditions.

    Science.gov (United States)

    Zhang, Ziheng; Marble, Andrew E; MacMillan, Bryce; Promislow, Keith; Martin, Jonathan; Wang, Haijiang; Balcom, Bruce J

    2008-10-01

    Water transport and water management are fundamental to polymer electrolyte membrane fuel cell operation. Accurate measurements of water content within and across the Nafion layer are required to elucidate water transport behavior and validate existing numerical models. We report here a direct measurement of water content profiles across a Nafion layer under wetting and drying conditions, using a novel magnetic resonance imaging methodology developed for this purpose. This method, multi-echo double half k-space spin echo single point imaging, based on a pure phase encode spin echo, is designed for high resolution 1D depth imaging of thin film samples. The method generates high resolution (drying, in addition to the steady state.

  7. Wetting and evaporation of salt-water nanodroplets: A molecular dynamics investigation

    OpenAIRE

    Zhang, Jun; Borg, Matthew; Sefiane, Khellil; Reese, Jason

    2015-01-01

    We employ molecular dynamics simulations to study the wetting and evaporation of salt-water nanodroplets on platinum surfaces. Our results show that the contact angle of the droplets increases with the salt concentration. To verify this, a second simulation system of a thin salt-water film on a platinum surface is used to calculate the various surface tensions. We find that both the solid-liquid and liquid-vapor surface tensions increase with salt concentration and as a result these cause an ...

  8. PROPERTIES OF SWIMMING WATER

    Directory of Open Access Journals (Sweden)

    Tayfun KIR

    2004-10-01

    Full Text Available Swimming waters may be hazardous on human health. So, The physicians who work in the facilities, which include swimming areas, are responsible to prevent risks. To ensure hygiene of swimming water, European Swimming Water Directive offers microbiological, physical, and chemical criteria. [TAF Prev Med Bull 2004; 3(5.000: 103-104

  9. PROPERTIES OF SWIMMING WATER

    OpenAIRE

    Tayfun KIR; Zakir COBANOÐLU

    2004-01-01

    Swimming waters may be hazardous on human health. So, The physicians who work in the facilities, which include swimming areas, are responsible to prevent risks. To ensure hygiene of swimming water, European Swimming Water Directive offers microbiological, physical, and chemical criteria. [TAF Prev Med Bull 2004; 3(5.000): 103-104

  10. Impacts of grass removal on wetting and actual water repellency in a sandy soil

    National Research Council Canada - National Science Library

    Klaas Oostindie; Louis W. Dekker; Jan G. Wesseling; Violette Geissen; Coen J. Ritsema

    2017-01-01

    Soil water content and actual water repellency were assessed for soil profiles at two sites in a bare and grasscovered plot of a sand pasture, to investigate the impact of the grass removal on both properties...

  11. Effect of various gelling cations on the physical properties of "wet" alginate films.

    Science.gov (United States)

    Harper, B Allison; Barbut, Shai; Lim, Loong-Tak; Marcone, Massimo F

    2014-04-01

    In this study, the physical properties of "wet" alginate films gelled with various divalent cations (Ba(2+) , Ca(2+) , Mg(2+) , Sr(2+) , and Zn(2+) ) were explored. Additionally, the effect of adding NaCl to the alginate film-forming solution prior to gelling was evaluated. Aside from Mg(2+) , all of the divalent cations were able to produce workable "wet" alginate films. Films gelled with BaCl2 (without added NaCl) had the highest (P alginate and Sr-alginate films had the highest elongation at break values. Adding NaCl to the alginate film-forming solution increased the viscosity of the solution. Films with added NaCl were less transparent and had lower tensile strength, elongation, and puncture strength than films formed without NaCl in the film-forming solution. ATR-FTIR results showed a slight shift in the asymmetric COO(-) vibrational peak of the alginate when the "wet" alginate films were gelled with Zn(2+) .

  12. The magnetic properties and microstructure of Co-Pt thin films using wet etching process.

    Science.gov (United States)

    Lee, Chang-Hyoung; Cho, Young-Lae; Lee, Won-Pyo; Suh, Su-Jeong

    2014-11-01

    Perpendicular magnetic recording (PMR) is a promising candidate for high density magnetic recording and has already been applied to hard disk drive (HDD) systems. However, media noise still limits the recording density. To reduce the media noise and achieve a high signal-to-noise ratio (SNR) in hard disk media, the grains of the magnetic layer must be magnetically isolated from each other. This study examined whether sputter-deposited Co-Pt thin films can have adjacent grains that are physically isolated. To accomplish this, the effects of the sputtering conditions and wet etching process on magnetic properties and the microstructure of the films were investigated. The film structure was Co-Pt (30 nm)/Ru (30 nm)/NiFe (10 nm)/Ta (5 nm). The composition of the Co-Pt thin films was Co-30.7 at.% Pt. The Co-Pt thin films were deposited in Ar gas at 5, 10, 12.5, and 15 mTorr. Wet etching process was performed using 7% nitric acid solution at room temperature. These films had high out-of-plane coercivity of up to 7032 Oe, which is twice that of the as-deposited film. These results suggest that wet etched Co-Pt thin films have weaker exchange coupling and enhanced out-of-plane coercivity, which would reduce the medium noise.

  13. Conditioning of Si-interfaces by wet-chemical oxidation: Electronic interface properties study by surface photovoltage measurements

    Science.gov (United States)

    Angermann, Heike

    2014-09-01

    The field-modulated surface photovoltage (SPV) method, a very surface sensitive technique, was utilized to determine electronic interface properties on wet-chemically oxidized and etched silicon (Si) interfaces. The influence of preparation-induced surface micro-roughness and un-stoichiometric oxides on the resulting the surface charge, energetic distribution Dit(E), and density Dit,min of rechargeable states was studied by simultaneous, spectroscopic ellipsometry (SE) measurements on polished Si(111) and Si(100) substrates. Based on previous findings and new research, a study of conventional and newly developed wet-chemical oxidation methods was established, correlating the interactions between involved oxidizing and etching solutions and the initial substrate morphology to the final surface conditioning. It is shown, which sequences of wet-chemical oxidation and oxide removal, have to be combined in order to achieve atomically smooth, hydrogen terminated surfaces, as well as ultra-thin oxide layers with low densities of rechargeable states on flat, saw damage etched, and textured Si substrates, as commonly applied in silicon device and solar cell manufacturing. These conventional strategies for wet-chemical pre-treatment are mainly based on concentrated solutions. Therefore, special attention was put on the development of more environmentally acceptable processes, utilizing e.g. hot pure water with low contents of oxygen or hydrochloric acid, and of ozone, working at ambient temperatures. According to our results, these methods could be a high quality and low cost alternative to current approaches with liquid chemicals for the preparation of hydrophobic Si substrate surfaces and ultra-thin passivating oxide layers. As demonstrated for selected examples, the effect of optimized wet-chemical pre-treatments can be preserved during subsequent soft plasma enhanced chemical vapor depositions of Si oxides (SiOx), or amorphous materials such as Si (a-Si:H), Si nitride (a

  14. Evaluation of supercritical water gasification and biomethanation for wet biomass utilization in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Matsumura, Yukihiko [Hiroshima Univ., Dept. of Mechanical System Engineering, Hiroshima (Japan)

    2002-08-01

    Two wet biomass gasification processes, supercritical water gasification and biomethanation, were evaluated from energy, environmental, and economic aspects. Gasification of 1 dry-t/d of water hyacinth was taken as a model case. Assumptions were made that system should be energetically independent, that no environmentally harmful material should be released, and that carbon dioxide should be removed from the product gas. Energy efficiency, carbon dioxide payback time, and price of the product gas were chosen as indices for energy, environmental, and economic evaluations, respectively. Under the conditions assumed here, supercritical water gasifications is evaluated to be more advantageous over biomethanation, but the cost of the product gas is still 1.86 times more expensive than city gas in Tokyo. To improve efficiency of supercritical water gasification, improvement of heat exchanger efficiency is effective. Utilization of fermentation sludge will make biomethanation much more advantageous. (Author)

  15. Mechano-activated surface modification of calcium carbonate in wet stirred mill and its properties

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Surface modification of calcium carbonate particles using sodium stearate(SDS) as a modification agent incorporated with the simultaneous wet ultra-fine grinding in the laboratory stirred mill was investigated. The physical properties and application properties of modified calcium carbonate were measured and evaluated. The action mechanism between SDS and calcium carbonate in the modification was studied by infrared spectrometry(IR) and X-ray photoelectron energy spectroscopy(XPS). The results indicate that the crushing mechanic force intensity can obviously influence the modification effect of calcium carbonate because of mechano-chemical effect. The hydrophilic surface of calcium carbonate is turned into hydrophobic after modification. The properties of polyethylene(PE) filled by modified calcium carbonate powder is markedly improved. And the adsorption of SDS could occur by chemical reaction with calcium carbonate surface.

  16. Adaptable bioinspired special wetting surface for multifunctional oil/water separation

    Science.gov (United States)

    Kavalenka, Maryna N.; Vüllers, Felix; Kumberg, Jana; Zeiger, Claudia; Trouillet, Vanessa; Stein, Sebastian; Ava, Tanzila T.; Li, Chunyan; Worgull, Matthias; Hölscher, Hendrik

    2017-01-01

    Inspired by the multifunctionality of biological surfaces necessary for the survival of an organism in its specific environment, we developed an artificial special wetting nanofur surface which can be adapted to perform different functionalities necessary to efficiently separate oil and water for cleaning accidental oil spills or separating industrial oily wastewater. Initial superhydrophobic nanofur surface is fabricated using a hot pulling method, in which nano- and microhairs are drawn out of the polymer surface during separation from a heated sandblasted steel plate. By using a set of simple modification techniques, which include microperforation, plasma treatment and subsequent control of storage environment, we achieved selective separation of either water or oil, variable oil absorption and continuous gravity driven separation of oil/water mixtures by filtration. Furthermore, these functions can be performed using special wetting nanofur made from various thermoplastics, including biodegradable and recyclable polymers. Additionally, nanofur can be reused after washing it with organic solvents, thus, further helping to reduce the environmental impacts of oil/water separation processes.

  17. Strength and Water Interactions of Cellulose I Filaments Wet-Spun from Cellulose Nanofibril Hydrogels

    Science.gov (United States)

    Lundahl, Meri J.; Cunha, A. Gisela; Rojo, Ester; Papageorgiou, Anastassios C.; Rautkari, Lauri; Arboleda, Julio C.; Rojas, Orlando J.

    2016-07-01

    Hydrogels comprising cellulose nanofibrils (CNF) were used in the synthesis of continuous filaments via wet-spinning. Hydrogel viscosity and spinnability, as well as orientation and strength of the spun filaments, were found to be strongly affected by the osmotic pressure as determined by CNF surface charge and solid fraction in the spinning dope. The tensile strength, Young’s modulus and degree of orientation (wide-angle X-ray scattering, WAXS) of filaments produced without drawing were 297 MPa, 21 GPa and 83%, respectively, which are remarkable values. A thorough investigation of the interactions with water using dynamic vapour sorption (DVS) experiments revealed the role of sorption sites in the stability of the filaments in wet conditions. DVS analysis during cycles of relative humidity (RH) between 0 and 95% revealed major differences in water uptake by the filaments spun from hydrogels of different charge density (CNF and TEMPO-oxidised CNF). It is concluded that the mechanical performance of filaments in the presence of water deteriorates drastically by the same factors that facilitate fibril alignment and, consequently, enhance dry strength. For the most oriented filaments, the maximum water vapour sorption at 95% RH was 39% based on dry weight.

  18. Fine tails reclamation research and development program : wet landscape water quality model development

    Energy Technology Data Exchange (ETDEWEB)

    Gulley, J. R.

    1993-07-01

    The 1992/93 wet landscape simulation model development project was summarized. The project included several tasks: (1)the development of a probabilistic version of the model; (2)the completion of a literature review; the completion of a comparative analysis of physical, chemical and biological characteristics of experimental pits; (3)the updating of the experimental pit model; (4)the development of a secondary production model; (5)the implementation of a food-chain model to simulate accumulation of contaminants; and (6)the completion of a preliminary evaluation of contaminant fate and transport for the wet landscape system. Each task was detailed and included as an appendix to the consultant`s report. As a result of the project, there is now a probabilistic water quality model configured for a wet landscape reclamation scenario. Second productivity modelling capabilities have been integrated to the model, as well as linkages with a food chain model and an off-site river model. The other tasks will be undertaken during succeeding years of the project. 1 ref.

  19. Bacterial spore heat resistance correlated with water content, wet density, and protoplast/sporoplast volume ratio.

    Science.gov (United States)

    Beaman, T C; Greenamyre, J T; Corner, T R; Pankratz, H S; Gerhardt, P

    1982-05-01

    Five types of dormant Bacillus spores, between and within species, were selected representing a 600-fold range in moist-heat resistance determined as a D100 value. The wet and dry density and the solids and water content of the entire spore and isolated integument of each type were determined directly from gram masses of material, with correction for interstitial water. The ratio between the volume occupied by the protoplast (the structures bounded by the inner pericytoplasm membrane) and the volume occupied by the sporoplast (the structures bounded by the outer pericortex membrane) was calculated from measurements made on electron micrographs of medially thin-sectioned spores. Among the various spore types, an exponential increase in the heat resistance correlated directly with the wet density and inversely with the water content and with the protoplast/sporoplast volume ratio. Altogether with results supported a hypothesis that the extent of heat resistance is based in whole or in part on the extent of dehydration and diminution of the protoplast in the dormant spore, without implications about physiological mechanisms for attaining this state.

  20. Water quality criteria for total suspended solids (TSS) in urban wet-weather discharges.

    Science.gov (United States)

    Rossi, L; Fankhauser, R; Chèvre, N

    2006-01-01

    Total suspended solids (TSS) from combined sewer overflows (CSOs) and stormwater discharges represent a crucial parameter for evaluating wet-weather pollution in urban areas. In fact, the increase of TSS in water during rain events can have ecotoxic effects on aquatic organisms. Furthermore, major potentially harmful substances such as heavy metals, PAHs and organic matter are adsorbed onto TSS and later settle on sediment. Water quality criteria for TSS consequently enable the risk of wet-weather pollution to be assessed, for instance to avoid detrimental effects on aquatic organisms. The criteria proposed in this study cover the short-term impact of TSS on fish (acute quality criteria AQC), taking into account the duration of their exposure in the receiving water. The concentration-exposure duration-effect curve proposed here thus predicts "ill effects" on fish for different exposure times and TSS concentrations. The ecotoxic effects of adsorbed pollutants are also taken into account with an additional safety factor. We implement this TSS criteria in a software that allows us to estimate the number of rain events that exceed a given morbidity threshold for fishes per year.

  1. A Novel Method for Measuring the Coarse Water Droplets in Wet Steam Flow in Steam Turbines

    Institute of Scientific and Technical Information of China (English)

    Xiaoshu Cai; Lili Wang; Yongzhi Pan; Xin Ouyan; Jianqi Shen

    2001-01-01

    Some optical probes based on light extinction have been developed to measure wemess dominated with fine droplets in steam turbine. However, coarse water droplets (hereafter referred to as CWD) that are the main cause of erosion of blade and of wetness loss of steam turbine can't be detected by the extinction probes because of its large size. In this paper, a new method - the light fluctuation method is presented that is capable of measuring the size of CWD. A new probe based on this method was developed for measuring the size of CWD as well as its velocity and concentration.

  2. Sputtered Ag thin films with modified morphologies: Influence on wetting property

    Energy Technology Data Exchange (ETDEWEB)

    Dutheil, P., E-mail: perrine.dutheil@univ-orleans.fr [GREMI, UMR 7344- Université D’Orléans, 14 rue d’Issoudun, BP 6744, Orléans 45067 (France); Thomann, A.L.; Lecas, T.; Brault, P. [GREMI, UMR 7344- Université D’Orléans, 14 rue d’Issoudun, BP 6744, Orléans 45067 (France); Vayer, M. [ICMN, UMR 7374- Université D’Orléans, 1b rue de la Férollerie, Orléans 45071 (France)

    2015-08-30

    Graphical abstract: - Highlights: • Ag thin films are deposited by DC magnetron sputtering on Si and W/Si layers. • The influence of the W underlayer morphology on Ag film growth is evidenced. • Variation of the Ag growth mode and roughness is investigated by SEM and AFM. • Wetting property is correlated to the roughness of Ag deposits on Si and W layers. - Abstract: Silver thin films with thickness ranging from 3 nm to 33 nm were sputter deposited onto silicon wafers and tungsten layers. Those W layers were previously synthesized in the same DC magnetron sputter deposition system with various experimental conditions (argon pressure, target to substrate distance) in order to stabilize different surface morphologies. SEM observations and AFM images showed that the growth mode of Ag films is similar on Si substrates and on the smoothest W layers, whereas it is modified for rough W layers made of sharp grains. The effect of the W layer morphology on Ag film growth was clearly evidenced when the deposition took place at high temperature. It is seen that performing the deposition onto substrates of various morphologies allows tailoring the wetting property of the Ag deposit.

  3. Effects of wet deposition on optical properties of the atmosphere over Bermuda and Barbados

    Science.gov (United States)

    Todd, Deborah L.; Keene, William C.; Moody, Jennie L.; Maring, Hal; Galloway, James N.

    2003-02-01

    Substantial spatial and temporal variabilities in chemical and physical properties of aerosols complicate attempts to model associated influences on global climate. Although wet deposition is the major mechanism by which most aerosols are removed from the atmosphere, direct effects of precipitation on radiative properties of the atmosphere are not well understood. To address this issue, attenuation coefficients for total insoluble constituents (ACt) and for nonvolatile (at 500°C) insoluble constituents (ACnv; primarily crustal dust) of precipitation at Bermuda and Barbados were measured at six wavelengths between 414 and 859 nm. Coefficients for volatile (at 500°C) insoluble constituents (ACv; primarily carbonaceous species) were calculated by difference. Between April and September, ACt at Bermuda was dominated by mineral constituents transported from North Africa, whereas carbonaceous species from North America were relatively low and exhibited no systematic seasonal variability. ACt and ACnv at Barbados were dominated by mineral dust, especially between April and September. Relative to ACv, ACnv decreased more rapidly with increasing wavelength. The wavelength dependencies of ACs for volatile and nonvolatile constituents at Bermuda were statistically indistinguishable from those at Barbados. The optical and chemical characteristics of precipitation were compared with scattering and absorption by ambient aerosols in associated air parcels to evaluate the influence of scavenging on the radiative properties of air. Although discernible relationships were evident, the small number of cases limited their applicability as reliable empirical predictors. However, these data do provide useful constraints for validating models of aerosol scavenging and wet removal on the optical properties of the troposphere.

  4. Two-photon laser confocal microscopy of micropermeability of resin-dentin bonds made with water or ethanol wet bonding.

    Science.gov (United States)

    Sauro, Salvatore; Watson, Timothy F; Mannocci, Francesco; Miyake, Katsuya; Huffman, Bradford P; Tay, Franklin R; Pashley, David H

    2009-07-01

    This study evaluated the micropermeability of six etch-and-rinse adhesives bonded to dentin. There were two principal groups: wet bonding with water or wet bonding with absolute ethyl alcohol. After bonding and the creation of composite build-ups, the pulp chambers were filled with 0.1% lucifer yellow. The contents of the pulp chamber were kept under 20 cm H(2)O pressure to simulate pulpal pressure for 3 h. The specimens were vertically sectioned into multiple 0.5-mm thick slabs that were polished and then examined using a two-photon confocal laser scanning microscope (TPCLSM). The results showed that specimens bonded with adhesives using the water wet-bonding condition all showed tracer taken up uniformly by the hybrid layer. This uptake of fluorescent tracer into the hybrid layer was quantified by computer software. The most hydrophobic experimental resins showed the highest fluorescent tracer uptake (ca. 1800 +/- 160 arbitrary fluorescent units/std. surface area). The most hydrophilic experimental resins showed the lowest tracer uptake into water-saturated hybrid layers. When ethanol wet-bonding was used, significantly less fluorescent tracer was seen in hybrid layers. The most hydrophilic experimental resins and Single Bond Plus showed little micropermeability. Clearly, ethanol wet-bonding seals dentin significantly better than water-wet dentin regardless of the adhesive in etch-and-rinse systems.

  5. Ternary System of Fe-based Ionic Liquid, Ethanol and Water for Wet Flue Gas Desulfurization

    Institute of Scientific and Technical Information of China (English)

    解美莹; 李沛沛; 郭惠锋; 高丽霞; 余江

    2012-01-01

    Fe-based ionic liquid (Fe-IL) was synthesized by mixing FeCl3·6H2O and 1-butyl-3-methylimidazolium chloride [Bmim]C1 in this paper. The phase diagram of a ternary Fe-IL, ethanol and water system was investigated to construct a ternary desulfurization solution for wet flue gas desulfurization. The effects of flow rate and concentration of SO2, reaction temperature, pH and Fe-IL fraction in aqueous desulfurization solution on the desulfiariza- tion efficiency were investigated. The results shows that the best composition of ternary desulfurization solution of Fe-IL, ethanol and water is 1 : 1.5 : 3 by volume ratio, and pH should be controlled at 2.0. Under such conditions, a desulfurization rate greater than 90% could be obtained. The product of sulfuric acid had inhibition effect on the wet desulfurization process. With applying this new ternary desulfurization solution, not only the catalyst Fe-IL can be recycled and reused, but also the product sulfuric acid can be separated directly from the ternary desulfurization system.

  6. Direct and accurate measurement of size dependent wetting behaviors for sessile water droplets

    Science.gov (United States)

    Park, Jimin; Han, Hyung-Seop; Kim, Yu-Chan; Ahn, Jae-Pyeong; Ok, Myoung-Ryul; Lee, Kyung Eun; Lee, Jee-Wook; Cha, Pil-Ryung; Seok, Hyun-Kwang; Jeon, Hojeong

    2015-12-01

    The size-dependent wettability of sessile water droplets is an important matter in wetting science. Although extensive studies have explored this problem, it has been difficult to obtain empirical data for microscale sessile droplets at a wide range of diameters because of the flaws resulting from evaporation and insufficient imaging resolution. Herein, we present the size-dependent quantitative change of wettability by directly visualizing the three phase interfaces of droplets using a cryogenic-focused ion beam milling and SEM-imaging technique. With the fundamental understanding of the formation pathway, evaporation, freezing, and contact angle hysteresis for sessile droplets, microdroplets with diameters spanning more than three orders of magnitude on various metal substrates were examined. Wetting nature can gradually change from hydrophobic at the hundreds-of-microns scale to super-hydrophobic at the sub-μm scale, and a nonlinear relationship between the cosine of the contact angle and contact line curvature in microscale water droplets was demonstrated. We also showed that the wettability could be further tuned in a size-dependent manner by introducing regular heterogeneities to the substrate.

  7. Hydrophobic pore array surfaces: wetting and interaction forces in water/ethanol mixtures.

    Science.gov (United States)

    Hansson, Petra M; Hormozan, Yashar; Brandner, Birgit D; Linnros, Jan; Claesson, Per M; Swerin, Agne; Schoelkopf, Joachim; Gane, Patrick A C; Thormann, Esben

    2013-04-15

    Interactions between and wetting behavior of structured hydrophobic surfaces using different concentrations of water/ethanol mixtures have been investigated. Silica surfaces consisting of pore arrays with different pore spacings and pore depths were made hydrophobic by silanization. Their static and dynamic contact angles were found to be independent of the pore depth while fewer pores on the surface, i.e. a closer resemblance to a flat surface, gave a lower contact angle. As expected, a higher amount of ethanol facilitated wetting on all the surfaces tested. Confocal Raman microscopy measurements proved both water and ethanol to penetrate into the pores. AFM colloidal probe force measurements clearly showed that formation of air cavitation was hindered between the hydrophobic surfaces in presence of ethanol, and an increase in ethanol concentration was followed by a smaller jump-in distance and a weaker adhesion force. On separation, an immediate jump-out of contact occurred. The measured forces were interpreted as being due to capillary condensation of ethanol between the surfaces giving rise to very unstable cavities immediately rupturing on surface separation.

  8. Forsterite Carbonation in Wet-scCO2: Dependence on Adsorbed Water Concentration

    Science.gov (United States)

    Loring, J.; Benezeth, P.; Qafoku, O.; Thompson, C.; Schaef, T.; Bonneville, A.; McGrail, P.; Felmy, A.; Rosso, K.

    2013-12-01

    Capturing and storing CO2 in basaltic formations is one of the most promising options for mitigating atmospheric CO2 emissions resulting from the burning of fossil fuels. These geologic reservoirs have high reactive potential for CO2-mineral trapping due to an abundance of divalent-cation containing silicates, such as forsterite (Mg2SiO4). Recent studies have shown that carbonation of these silicates under wet scCO2 conditions, e. g. encountered near a CO2 injection well, proceeds along a different pathway and is more effective than in CO2-saturated aqueous fluids. The presence of an adsorbed water film on the forsterite surface seems to be key to reactivity towards carbonation. In this study, we employed in situ high pressure IR spectroscopy to investigate the dependence of adsorbed water film thickness on forsterite carbonation chemistry. Post reaction ex situ SEM, TEM, TGA, XRD, and NMR measurements will also be discussed. Several IR titrations were performed of forsterite with water at 50 °C and 90 bar scCO2. Aliquots of water were titrated at 4-hour reaction-time increments. Once a desired total water concentration was reached, data were collected for about another 30 hours. One titration involved 10 additions, which corresponds to 6.8 monolayers of adsorbed water. Clearly, a carbonate was precipitating, and its spectral signature matched magnesite. Another titration involved 8 aliquots, or up to 4.4 monolayers of water. The integrated absorbance under the CO stretching bands of carbonate as a function of time after reaching 4.4 monolayers showed an increase and then a plateau. We are currently unsure of the identity of the carbonate that precipitated, but it could be an amorphous anhydrous phase or magnesite crystals with dimensions of only several nanometers. A third titration only involved 3 additions, or up to 1.6 monolayers of water. The integrated absorbance under the CO stretching bands of carbonate as a function of time after reaching 1.6 monolayers

  9. The dynamical and microphysical properties of wet season convection in Darwin as a function of wet season regime.

    Science.gov (United States)

    Jackson, Robert; Collis, Scott; Protat, Alain; Majewski, Leon; Louf, Valentin; Potvin, Corey; Lang, Timothy

    2017-04-01

    A known deficiency of general circulation models (GCMs) is in their representation of convection (Arakawa 2004), typically parameterized using given assumptions about entrainment rates and mass fluxes that depend on the dynamical and microphysical characteristics of convection and lack any sort of representation of the organization of convection. Furthermore, mechanisms that couple large scale forcing and convective organization are poorly represented (Del Genio 2012). The Accelerated Climate Model for Energy (ACME) version 1 aims to run at resolutions of 25 km, too coarse for convective parameterizations used in large eddy simulations but too fine for typical convective parameterizations used in GCMs. This prompts the need for observational datasets to validate simulations and guide model development in ACME in several regions of the globe. The focus of this study will be at the Tropical Western Pacific (TWP) site in Darwin, Australia and the surrounding maritime continent. In Darwin, well defined forcing regimes occur during the wet season of September to April with the onset and the break of the Northern Australian Monsoon (Drosdowsky 1996; Pope et al. 2009). In this study, the vertical velocities retrieved from over ten years of continuous plan position indicator scans from the C-band POLarimetric and Berrima radars stationed at the Atmospheric Radiation Measurement TWP site in Darwin are derived. This long term dataset in such a region provides an opportunity to explore the statistics of vertical velocities in convection as a function of large scale forcing and modes of convective organization. Initial attempts to classify the convective organizational state and derive vertical velocities using three-dimensional variational data retrieval (Potvin et al. 2012) are shown. The results will be used to validate ACME Regionally Refined Mesh simulations over Darwin as well as guide convective parameterization development.

  10. Control on wetting properties of spin-deposited silica films by surface silylation method

    Energy Technology Data Exchange (ETDEWEB)

    Rao, A. Venkateswara, E-mail: avrao2012@gmail.com [Air Glass Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004, Maharashtra (India); Latthe, Sanjay S.; Dhere, Sunetra L.; Pawar, Swapnali S. [Air Glass Laboratory, Department of Physics, Shivaji University, Kolhapur 416 004, Maharashtra (India); Imai, Hiroaki [Faculty of Science and Technology, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522 (Japan); Ganesan, V. [CSR, Indore Centre, University Campus, Khandwa Road, Indore 452 017, Madhyapradesh (India); Gupta, Satish C.; Wagh, Pratap B. [Applied Physics Division, Bhabha Atomic Research Centre (BARC), Trombay, Mumbai 400 085 (India)

    2010-01-15

    Control on the wettability of solid materials by liquid is a classical and key issue in surface engineering. Optically transparent water-repellent silica films have been spin-deposited on glass substrates at room temperature ({approx}27 deg. C). The wetting behavior of silica films was controlled by surface silylation method using dimethylchlorosilane (DMCS) as a silylating reagent. A coating sol was prepared by keeping the molar ratio of methyltrimethoxysilane (MTMS) precursor, methanol (MeOH) solvent, water (H{sub 2}O) constant at 1:8.8:2.64 respectively, with 4 M NH{sub 4}OH as a catalyst throughout the experiments and the amount of DMCS in hexane was varied from 0 to 12 vol.%. It was found that with an increase in vol.% of DMCS, the water contact angle values of the films increased from 78 deg. to 136 deg. At 12 vol.% of DMCS, the film shows static water contact angle as high as 136 deg. and water sliding angle as low as 18 deg. The hydrophobic silica films retained their water repellency up to a temperature 295 deg. C and above this temperature the films show superhydrophilic behavior. These results are compared with our earlier research work done on silylation of silica surface using hexamethyldisilazane (HMDZ) and trimethylchlorosilane (TMCS). The hydrophobic silica films were characterized by taking into consideration the Fourier transform infrared (FT-IR) spectroscopy, thermo gravimetric-differential thermal (TG-DT) analyses, scanning electron microscopy (SEM), atomic force microscopy (AFM), % of optical transmission, thermal and chemical aging tests, humidity tests, static and dynamic water contact angle measurements.

  11. Control on wetting properties of spin-deposited silica films by surface silylation method

    Science.gov (United States)

    Rao, A. Venkateswara; Latthe, Sanjay S.; Dhere, Sunetra L.; Pawar, Swapnali S.; Imai, Hiroaki; Ganesan, V.; Gupta, Satish C.; Wagh, Pratap B.

    2010-01-01

    Control on the wettability of solid materials by liquid is a classical and key issue in surface engineering. Optically transparent water-repellent silica films have been spin-deposited on glass substrates at room temperature (˜27 °C). The wetting behavior of silica films was controlled by surface silylation method using dimethylchlorosilane (DMCS) as a silylating reagent. A coating sol was prepared by keeping the molar ratio of methyltrimethoxysilane (MTMS) precursor, methanol (MeOH) solvent, water (H 2O) constant at 1:8.8:2.64 respectively, with 4 M NH 4OH as a catalyst throughout the experiments and the amount of DMCS in hexane was varied from 0 to 12 vol.%. It was found that with an increase in vol.% of DMCS, the water contact angle values of the films increased from 78° to 136°. At 12 vol.% of DMCS, the film shows static water contact angle as high as 136° and water sliding angle as low as 18°. The hydrophobic silica films retained their water repellency up to a temperature 295 °C and above this temperature the films show superhydrophilic behavior. These results are compared with our earlier research work done on silylation of silica surface using hexamethyldisilazane (HMDZ) and trimethylchlorosilane (TMCS). The hydrophobic silica films were characterized by taking into consideration the Fourier transform infrared (FT-IR) spectroscopy, thermo gravimetric-differential thermal (TG-DT) analyses, scanning electron microscopy (SEM), atomic force microscopy (AFM), % of optical transmission, thermal and chemical aging tests, humidity tests, static and dynamic water contact angle measurements.

  12. Enhancement of dynamic wetting properties by direct fabrication on robust micro-micro hierarchical polymer surfaces

    Science.gov (United States)

    Chu, Donghui; Nemoto, Akihiko; Ito, Hiroshi

    2014-05-01

    Understanding evaporation phenomena on hierarchical surfaces is of crucial importance for the design of robust superhydrophobic polymer structures for various applications. This fabrication method enables precise control of the dimensions to elucidate the dynamic wetting behavior affected by geometric parameters. That behavior exhibits three distinct evaporation modes: a constant contact line (CCL), a constant contact angle (CCA), and mixed mode during the droplet evaporation. The droplet evaporation results show that the sticky CCL mode and the Cassie-Wenzel transition can be prevented by engineering hierarchy integration. Moreover, the CCL-CCA transition point time scale exhibits remarkable dependence on surface dimensions such as the area fraction and solid-liquid contact line. Finally, the fabricated hierarchical structures indicate remarkable superhydrophobic properties, static contact angle above 160° and low sliding angle under 10°, with good durability in terms of aging effect and mechanical robustness for 2 months.

  13. Image Charge Effects in the Wetting Behavior of Alkanes on Water with Accounting for Water Solubility

    Directory of Open Access Journals (Sweden)

    Kirill A. Emelyanenko

    2016-03-01

    Full Text Available Different types of surface forces, acting in the films of pentane, hexane, and heptane on water are discussed. It is shown that an important contribution to the surface forces originates from the solubility of water in alkanes. The equations for the distribution of electric potential inside the film are derived within the Debye-Hückel approximation, taking into account the polarization of the film boundaries by discrete charges at water-alkane interface and by the dipoles of water molecules dissolved in the film. On the basis of above equations we estimate the image charge contribution to the surface forces, excess free energy, isotherms of water adsorption in alkane film, and the total isotherms of disjoining pressure in alkane film. The results indicate the essential influence of water/alkane interface charging on the disjoining pressure in alkane films, and the wettability of water surface by different alkanes is discussed.

  14. Wetting Splashing

    CERN Document Server

    Tsai, Peichun; Dijkstra, Remko; Lohse, Detlef

    2010-01-01

    We present fluid dynamics videos illustrating wetting splashing-produced by water drop impact onto hydrophobic microstructures at high impact velocity ($\\sim 3$ ms$^{-1}$). The substrate consists of regular and transparent microtextures in square or hexagonal lattice, yielding a high contact angle of $\\sim 150 ^\\circ$. Our high speed top-or-bottom view recordings through the transparent surface shed light on the solid-liquid-air interfaces at impact. Despite the superhydrophobicity of the latticed micropillars (of a periodicity of $10 {\\mu}m), water droplet wets a certain central area and moreover entraps an air bubble beneath the droplet. Besides the central wet area, lamella surf on air splashing outward at high impinging velocity. The effects of micropatterns and air pressure on the impact outcome are also examined. We show that microscopic boundary condition, imposed by the solid texture, profoundly influences the macroscopic flow dynamics upon superhydrophobic surfaces at high impinging velocity. In addi...

  15. Wetting and evaporation of salt-water nanodroplets: A molecular dynamics investigation

    Science.gov (United States)

    Zhang, Jun; Borg, Matthew K.; Sefiane, Khellil; Reese, Jason M.

    2015-11-01

    We employ molecular dynamics simulations to study the wetting and evaporation of salt-water nanodroplets on platinum surfaces. Our results show that the contact angle of the droplets increases with the salt concentration. To verify this, a second simulation system of a thin salt-water film on a platinum surface is used to calculate the various surface tensions. We find that both the solid-liquid and liquid-vapor surface tensions increase with salt concentration and as a result these cause an increase in the contact angle. However, the evaporation rate of salt-water droplets decreases as the salt concentration increases, due to the hydration of salt ions. When the water molecules have all evaporated from the droplet, two forms of salt crystals are deposited, clump and ringlike, depending on the solid-liquid interaction strength and the evaporation rate. To form salt crystals in a ring, it is crucial that there is a pinned stage in the evaporation process, during which salt ions can move from the center to the rim of the droplets. With a stronger solid-liquid interaction strength, a slower evaporation rate, and a higher salt concentration, a complete salt crystal ring can be deposited on the surface.

  16. Wetting and evaporation of salt-water nanodroplets: A molecular dynamics investigation.

    Science.gov (United States)

    Zhang, Jun; Borg, Matthew K; Sefiane, Khellil; Reese, Jason M

    2015-11-01

    We employ molecular dynamics simulations to study the wetting and evaporation of salt-water nanodroplets on platinum surfaces. Our results show that the contact angle of the droplets increases with the salt concentration. To verify this, a second simulation system of a thin salt-water film on a platinum surface is used to calculate the various surface tensions. We find that both the solid-liquid and liquid-vapor surface tensions increase with salt concentration and as a result these cause an increase in the contact angle. However, the evaporation rate of salt-water droplets decreases as the salt concentration increases, due to the hydration of salt ions. When the water molecules have all evaporated from the droplet, two forms of salt crystals are deposited, clump and ringlike, depending on the solid-liquid interaction strength and the evaporation rate. To form salt crystals in a ring, it is crucial that there is a pinned stage in the evaporation process, during which salt ions can move from the center to the rim of the droplets. With a stronger solid-liquid interaction strength, a slower evaporation rate, and a higher salt concentration, a complete salt crystal ring can be deposited on the surface.

  17. A comparison between wet canopy evaporation estimated by stable isotope ratios of water and canopy interception measured by water balance

    Science.gov (United States)

    Murakami, Shigeki; Hattori, Shohei; Uemura, Ryu

    2017-04-01

    Some papers proved that canopy interception is proportional to rainfall not only on a rain event basis but also on an hourly basis (e.g. Murakami, 2006, J. Hydrol.; Saito et al., 2013, J. Hydrol.). However, theoretically, evaporation does not depend on rainfall amount. These results are enigmatic and we need to reevaluate wet canopy evaporation. We measured gross rainfall and net rainfall in a plastic Christmas tree stand with a height of 165 cm placed on a 180-cm square tray as described in Murakami and Toba (2013, Hydrol. Res. Lett.). The measurement was conducted outside under natural rainfall. We also estimated wet canopy evaporation using stable isotope ratios of water. During a rain event, we manually sampled gross and net rainwater on an hourly basis. Evaporation was calculated using the difference between the δ18O (or δ2H) values in gross and net rainfall using isotope fractionation factor. Total gross rainfall in a target rain event in October, 2014, was 28.0 mm and net rainfall (discharge from the tray) was 22.7 mm, i.e. canopy interception was 5.3 mm (18.9% of gross rainfall). The δ18O (or δ2H) value in net rainfall was higher than that in gross rainfall because of fractionation by evaporation on wet canopy surface. Hourly evaporation calculated by the values of δ18O varied from 2% to 24% of gross rainfall, and the weighted average by hourly gross rainfall was 5.2% of gross rainfall. Further, we estimated rainfall interception using a tank model (Yoshida et al., 1993) assuming constant evaporation rate, i.e. 20% of gross rainfall. Total net rainfall calculated by the model was 23.1 mm, i.e. calculated canopy interception was 4.9 mm (17.5% of gross rainfall). Then, keeping the parameters of the model, we simulated net rainfall using hourly surface evaporation obtained by the δ18O values. Calculated net rainfall was 25.6 mm, i.e. wet canopy evaporation was only 2.4 mm (8.6% of gross rainfall). So far, possible explanation of the discrepancy between

  18. The mechanism of lipids extraction from wet microalgae Scenedesmus sp. by ionic liquid assisted subcritical water

    Science.gov (United States)

    Yu, Zhuanni; Chen, Xiaolin; Xia, Shuwei

    2016-06-01

    In this paper, the total sugar concentration, protein concentration, lipid yield and morphology characteristics of the algae residue were determined to explain the mechanism of lipids extraction from wet microalgae Scenedesmus sp. by ionic liquid assisted subcritical water. The results showed similar variation for the sugar, protein and lipid. However, the total sugar was more similar to lipids yield, so the results showed that the reaction between ionic liquid and cellulose and hemicellulose in cell wall was the most important step which determined the lipids extration directly. And the total sugar variation may be representing the lipids yield. For later lipids extraction, we can determine the total sugar concentration to predict the extraction end product.

  19. Fe-based magnetic nanomaterials: Wet chemical synthesis, magnetic properties and exploration on applications

    Science.gov (United States)

    Xiaoliang, Hong

    Even though the start of research based on Fe-based magnetic nanomaterials could be dated back to hundreds years ago, the considerably large amount of emerging fields for their applications, including spintronic structures in information storage, biomedical and environmental applications, magnetic sensors, magnetic energy harvesters, has spurred renewed interest on the application-related properties of Fe-based nanomaterial in both the nanoparticle and film forms. Besides, an exploration of a simple, wide, effective technique that can be used for growth of high-quality Fe-based magnetic nanoparticles and films is of great importance for better materialization of these potential Fe-based devices. This thesis mainly focuses on fabricating different magnetic Fe-based materials (ferrites and ferrous alloys, nanoparticle and film) with wet chemical method, investigating their growth mechanism and magnetic and electrical properties. In addition, the possible applications of as-fabricated Fe-based nanoparticles and films are studied. The contribution of the work is summarized as below: (1) Investigation indicated that the external magnetic field plays an important role in determining the microstructure, magnetic properties of the Fe3O4 nanoparticles. The magnetic field can promote the change of Fe3O4 nanocuboctahedrons to nanocubes. Compared the hyperthermia property of as-fabricated nanocuboctahedrons and nanocubes Fe3O4, the intrinsic loss power (ILP) of the Fe3O4 nanocubes was much higher than that of nanocuboctahedrons due to the surface magnetic effect. (2) A general and facile method for broadly deposition of thick Fe 3O4 film and other ferrites has been demonstrated. It had been found that the epitaxial high-quality Fe3O4 film could be deposited either on MgO substrates directly or Si substrates with Fe3O4 seed layer deposited by PLD. As-deposited Fe 3O4 film could be easily patterned and shows potential applications for microwave and MEMS supercapacitor. Besides

  20. Properties of Water in Nanovolumes

    CERN Document Server

    Górski, N I

    2003-01-01

    This small review considers results of investigations carried out at a small-angle scattering facility in Dubna (the fourth channel of the IBR-2 reactor) with the aim of studying the properties of water in small volumes. Some physical aspects of dimensional effects for water drops are discussed. Peculiarities of the micellar objects used for the studies are pointed out. It is shown that the density of water in small volumes differs severalfold from the macroscopic one. References to works on contrast variation published earlier are given.

  1. Understanding the wetting properties of nanostructured selenium coatings: the role of nanostructured surface roughness and air-pocket formation

    Directory of Open Access Journals (Sweden)

    Tran PA

    2013-05-01

    Full Text Available Phong A Tran,1,2 Thomas J Webster31Department of Chemical and Biomolecular Engineering, University of Melbourne, Melbourne, VIC, Australia; 2The Particulate Fluid Processing Centre, University of Melbourne, Melbourne, VIC, Australia; 3Department of Chemical Engineering and Program in Bioengineering, Northeastern University, Boston, MA, USAAbstract: Wetting properties of biomaterials, in particular nanomaterials, play an important role, as these influence interactions with biological elements, such as proteins, bacteria, and cells. In this study, the wetting phenomenon of titanium substrates coated with selenium nanoparticles was studied using experimental and mathematical modeling tools. Importantly, these selenium-coated titanium substrates were previously reported to increase select protein adsorption (such as vitronectin and fibronectin, to decrease bacteria growth, and increase bone cell growth. Increased selenium nanoparticle coating density resulted in higher contact angles but remained within the hydrophilic regime. This trend was found in disagreement with the Wenzel model, which is widely used to understand the wetting properties of rough surfaces. The trend also did not fit well with the Cassie–Baxter model, which was developed to understand the wetting properties of composite surfaces. A modified wetting model was thus proposed in this study, to understand the contributing factors of material properties to the hydrophilicity/hydrophobicity of these nanostructured selenium-coated surfaces. The analysis and model created in this study can be useful in designing and/or understanding the wetting behavior of numerous biomedical materials and in turn, biological events (such as protein adsorption as well as bacteria and mammalian cell functions.Keywords: hydrophilicity, hydrophobicity, Wenzel model, Cassie–Baxter model, free energy, implant material, proteins, cells, bacteria

  2. Review of thermo-physical properties, wetting and heat transfer characteristics of nanofluids and their applicability in industrial quench heat treatment

    Directory of Open Access Journals (Sweden)

    Ramesh Gopalan

    2011-01-01

    Full Text Available Abstract The success of quenching process during industrial heat treatment mainly depends on the heat transfer characteristics of the quenching medium. In the case of quenching, the scope for redesigning the system or operational parameters for enhancing the heat transfer is very much limited and the emphasis should be on designing quench media with enhanced heat transfer characteristics. Recent studies on nanofluids have shown that these fluids offer improved wetting and heat transfer characteristics. Further water-based nanofluids are environment friendly as compared to mineral oil quench media. These potential advantages have led to the development of nanofluid-based quench media for heat treatment practices. In this article, thermo-physical properties, wetting and boiling heat transfer characteristics of nanofluids are reviewed and discussed. The unique thermal and heat transfer characteristics of nanofluids would be extremely useful for exploiting them as quench media for industrial heat treatment.

  3. Review of thermo-physical properties, wetting and heat transfer characteristics of nanofluids and their applicability in industrial quench heat treatment.

    Science.gov (United States)

    Ramesh, Gopalan; Prabhu, Narayan Kotekar

    2011-04-14

    The success of quenching process during industrial heat treatment mainly depends on the heat transfer characteristics of the quenching medium. In the case of quenching, the scope for redesigning the system or operational parameters for enhancing the heat transfer is very much limited and the emphasis should be on designing quench media with enhanced heat transfer characteristics. Recent studies on nanofluids have shown that these fluids offer improved wetting and heat transfer characteristics. Further water-based nanofluids are environment friendly as compared to mineral oil quench media. These potential advantages have led to the development of nanofluid-based quench media for heat treatment practices. In this article, thermo-physical properties, wetting and boiling heat transfer characteristics of nanofluids are reviewed and discussed. The unique thermal and heat transfer characteristics of nanofluids would be extremely useful for exploiting them as quench media for industrial heat treatment.

  4. Mechanical and wet tribological properties of carbon fabric/phenolic composites with different weave filaments counts

    Science.gov (United States)

    Wenbin, Li; Jianfeng, Huang; Jie, Fei; Liyun, Cao; Chunyan, Yao

    2015-10-01

    Carbon fabric/phenolic composites with different weave filaments counts were prepared by dip-coating and hot-press techniques, and then their mechanical and wet tribological properties were investigated based on the analysis of the three-dimensional surface profiles and the pore structures. Results show that the mechanical properties (elastic modulus, flexural modulus, tensile modulus, flexural strength and tensile strength) of the 3K carbon fabric/phenolic composites (Composite A) are better than that of the 12K carbon fabric/phenolic composites (Composite B). Fractured surfaces observation suggests that the dominant tensile failure mechanism is fiber breakage for Composite A and matrix fracture for Composite B. Compared with Composite B, Composite A possesses high friction coefficient in different loads and at different sliding speeds, and the friction coefficient of Composite A is more sensitive to load and sliding speed. The wear rate of Composite B is 39% greater than that of Composite A and the wear features of worn surfaces demonstrate the excellent wear resistance for Composite A. Based on the observation of worn surface, the wear mechanisms are presented.

  5. Preparation of silica thin films by novel wet process and study of their optical properties.

    Science.gov (United States)

    Im, Sang-Hyeok; Kim, Nam-Jin; Kim, Dong-Hwan; Hwang, Cha-Won; Yoon, Duck-Ki; Ryu, Bong-Ki

    2012-02-01

    Silicon dioxide (SiO2) thin films have gained considerable attention because of their various industrial applications. For example, SiO2 thin films are used in superhydrophilic self-cleaning surface glass, UV protection films, anti-reflection coatings, and insulating materials. Recently, many processes such as vacuum evaporation, sputtering, chemical vapor deposition, and spin coating have been widely applied to prepare thin films of functionally graded materials. However, these processes suffer from several engineering problems. For example, a special apparatus is required for the deposition of films, and conventional wet processes are not suitable for coating the surfaces of substrates with a large surface area and complex morphology. In this study, we investigated the film morphology and optical properties of SiO2 films prepared by a novel technique, namely, liquid phase deposition (LPD). Images of the SiO2 films were obtained by scanning electron microscopy (SEM) and atomic force microscopy (AFM) in order to study the surface morphology of these films: these images indicate that films deposited with different reaction times were uniform and dense and were composed of pure silica. Optical properties such as refractive index and transmittance were estimated by UV-vis spectroscopy and ellipsometry. SiO2 films with porous structures at the nanometer scale (100-250 nm) were successfully produced by LPD. The deposited film had excellent transmittance in the visible wavelength region.

  6. A new approach of tailoring wetting properties of TiO2 nanotubular surfaces

    KAUST Repository

    Isimjan, Tayirjan T.

    2012-11-01

    TiO2 nanotube layers were grown on a Ti surface by electrochemical anodization. As prepared, these layers showed a superhydrophilic wetting behavior. Modified with 1H, 1H, 2H, 2H-perfluorooctyltriethoxysilane (PTES), the layers showed a superhydrophobic behavior. We demonstrate how to change the surface characteristics of the TiO2 nanotube layers in order to achieve any desirable degree of hydrophobicity between 100° to 170°. The treated superhydrophobic TiO2 nanotube layers have an advanced contact angle exceeding 165°, a receding angle more than 155°and a slide angle less than 5°. It is found that the surface morphology of the film which depends on anodization time among other variables, has a great influence on the superhydrophobic properties of the surface after PTES treatment. The hydrodynamic properties of the surface are discussed in terms of both Cassie and Wenzel mechanisms. The layers are characterized with dynamic contact angle measurements, SEM, and XPS analyses. © 2012 American Scientific Publishers.

  7. Novel structural and magnetic properties of Mg doped copper nanoferrites prepared by conventional and wet methods

    Energy Technology Data Exchange (ETDEWEB)

    Ahmed, M.A., E-mail: moala47@hotmail.com [Materials Science Lab. (1), Physics Department, Cairo University, Giza (Egypt); Afify, H.H.; El Zawawia, I.K.; Azab, A.A. [Solid State Physics Department, National Research Center, Dokki, Cairo (Egypt)

    2012-07-15

    Nanoferrites of the general formula Cu{sub 1-x}Mg{sub x}Fe{sub 2}O{sub 4} with 0{<=}x{<=}0.6 were prepared by standard ceramic and wet methods. The structure was studied by X-ray diffraction and IR spectroscopy. The density and lattice constant were calculated and reported. The particle size of the prepared nanoferrites ranged from 8.7 to 41.1 nm. It was found that the lattice parameter decreases with increasing cation substitution of Mg{sup 2+} due to the difference of ionic radius and atomic mass. The dc magnetic susceptibility was measured out using Faraday's method. The magnetic hysteresis measurement was performed using a vibrating sample magnetometer. Magnetic constants such as Curie temperature, effective magnetic moment, saturation magnetization, remanent magnetization and corecivicty were obtained and reported. The magnetic constants decrease with increasing Mg{sup 2+}, except the remanent magnetization which increased. - Highlights: Black-Right-Pointing-Pointer We study the effect of Mg{sup 2+} on structural and magnetic properties of copper ferrite prepared by the different methods. Black-Right-Pointing-Pointer To determine which method gives the smallest particle size and optimize the physical properties. Black-Right-Pointing-Pointer To determine which sample is suitable for different applications.

  8. Predicting Pumpability and Shootability of Crushed Aggregate Wet-Mix Shotcrete Based on Rheological Properties

    Directory of Open Access Journals (Sweden)

    Kyong-Ku Yun

    2016-01-01

    Full Text Available This study aims to estimate the pumpability and shootability of wet-mix shotcrete (WMS made with crushed aggregates and various admixtures such as silica fume, fly ash, ground granulated blast furnace slag (GGBFS, metakaolin, and steel fiber based on rheological properties. The IBB rheometer was employed as an apparatus to measure the rheological properties of freshly mixed shotcrete such as flow resistance and torque viscosity. Results have shown that the use of silica fume and metakaolin led to satisfactory pumpability, whereas mixtures with fly ash and steel fiber failed to meet the pumping criteria at normal pump pressure. The build-up thickness, an indicator to represent shotcrete shootability, was predicted to vary between 68 and 218 mm, demonstrating that the use of admixtures resulted in a wide spectrum of shootability. In particular, the use of metakaolin was found to substantially increase the predicted build-up thickness only with a small replacement. The findings of this study are expected to be used as an easy-to-use guideline for estimating pumpability and shootability of WMS when no compliance testing data is available.

  9. Slash Incorporation for Amelioration of Site, Soil and Hydrologic Properties on Pocosins and Wet Flats in North Carolina

    Science.gov (United States)

    William A. Lakel; W. Michael Aust; Emily A. Carter; Bryce J. Stokes; Marilyn A. Buford; Felipe G. Sanchez

    1999-01-01

    It was hypothesized that mulching and incorporation of slash as part of site preparation treatments could affect soil water characteristics. Two forested wetland sites, an organic pocosin and a mineral wet flat. located in the lower coastal plain of North Carolina, were selected for treatments. Treatments consisted of slash mulching and incorporation in comoinations...

  10. Leaching and antimicrobial properties of silver nanoparticles loaded onto natural zeolite clinoptilolite by ion exchange and wet impregnation

    CSIR Research Space (South Africa)

    Missengue, RNM

    2015-11-01

    Full Text Available This study aimed to compare the leaching and antimicrobial properties of silver that was loaded onto the natural zeolite clinoptilolite by ion exchange and wet impregnation. Silver ions were reduced using sodium borohydride (NaBH(sub4...

  11. Method of producing an item with enhanced wetting properties by fast replication and replication tool used in the method

    DEFF Research Database (Denmark)

    2016-01-01

    The invention relates to a replication tool (1) for producing an item (4) with enhanced wetting properties by fast replication, such as injection moulding or extrusion coating. The replication tool (1) comprises a tool surface (2a, 2b) defining a general shape of the item (4). The tool surface (2a...

  12. Impacts of the Manaus pollution plume on the microphysical properties of Amazonian warm-phase clouds in the wet season

    Science.gov (United States)

    Cecchini, Micael A.; Machado, Luiz A. T.; Comstock, Jennifer M.; Mei, Fan; Wang, Jian; Fan, Jiwen; Tomlinson, Jason M.; Schmid, Beat; Albrecht, Rachel; Martin, Scot T.; Artaxo, Paulo

    2016-06-01

    The remote atmosphere over the Amazon can be similar to oceanic regions in terms of aerosol conditions and cloud type formations. This is especially true during the wet season. The main aerosol-related disturbances over the Amazon have both natural sources, such as dust transport from Africa, and anthropogenic sources, such as biomass burning or urban pollution. The present work considers the impacts of the latter on the microphysical properties of warm-phase clouds by analysing observations of the interactions between the Manaus pollution plume and its surroundings, as part of the GoAmazon2014/5 Experiment. The analysed period corresponds to the wet season (specifically from February to March 2014 and corresponding to the first Intensive Operating Period (IOP1) of GoAmazon2014/5). The droplet size distributions reported are in the range 1 µm ≤ D ≤ 50 µm in order to capture the processes leading up to the precipitation formation. The wet season largely presents a clean background atmosphere characterized by frequent rain showers. As such, the contrast between background clouds and those affected by the Manaus pollution can be observed and detailed. The focus is on the characteristics of the initial microphysical properties in cumulus clouds predominantly at their early stages. The pollution-affected clouds are found to have smaller effective diameters and higher droplet number concentrations. The differences range from 10 to 40 % for the effective diameter and are as high as 1000 % for droplet concentration for the same vertical levels. The growth rates of droplets with altitude are slower for pollution-affected clouds (2.90 compared to 5.59 µm km-1), as explained by the absence of bigger droplets at the onset of cloud development. Clouds under background conditions have higher concentrations of larger droplets (> 20 µm) near the cloud base, which would contribute significantly to the growth rates through the collision-coalescence process. The overall shape

  13. Impacts of the Manaus pollution plume on the microphysical properties of Amazonian warm-phase clouds in the wet season

    Energy Technology Data Exchange (ETDEWEB)

    Cecchini, Micael A.; Machado, Luiz A. T.; Comstock, Jennifer M.; Mei, Fan; Wang, Jian; Fan, Jiwen; Tomlinson, Jason M.; Schmid, Beat; Albrecht, Rachel; Martin, Scot T.; Artaxo, Paulo

    2016-01-01

    The remote atmosphere over the Amazon can be similar to oceanic regions in terms of aerosol conditions and cloud type formations. This is especially true during the wet season. The main aerosol-related disturbances over the Amazon have both natural sources, such as dust transport from Africa, and anthropogenic sources, such as biomass burning or urban pollution. The present work considers the impacts of the latter on the microphysical properties of warm-phase clouds by analysing observations of the interactions between the Manaus pollution plume and its surroundings, as part of the GoAmazon2014/5 Experiment. The analysed period corresponds to the wet season (specifically from February to March 2014 and corresponding to the first Intensive Operating Period (IOP1) of GoAmazon2014/5). The droplet size distributions reported are in the range 1 µm ≤ D≤50 µm in order to capture the processes leading up to the precipitation formation. The wet season largely presents a clean background atmosphere characterized by frequent rain showers. As such, the contrast between background clouds and those affected by the Manaus pollution can be observed and detailed. The focus is on the characteristics of the initial microphysical properties in cumulus clouds predominantly at their early stages. The pollution-affected clouds are found to have smaller effective diameters and higher droplet number concentrations. The differences range from 10 to 40% for the effective diameter and are as high as 1000% for droplet concentration for the same vertical levels. The growth rates of droplets with altitude are slower for pollution-affected clouds (2.90 compared to 5.59 µm km₋1), as explained by the absence of bigger droplets at the onset of cloud development. Clouds under background conditions have higher concentrations of larger droplets (>20 µm) near the cloud base, which would contribute significantly to the growth rates through the collision

  14. Design of self-dispersible dry nanosuspension through wet milling and spray freeze-drying for poorly water-soluble drugs.

    Science.gov (United States)

    Niwa, Toshiyuki; Danjo, Kazumi

    2013-11-20

    The purpose of the present research is to establish a novel nanosizing technique starting from wet nano-milling, named "dry nanosuspension" technique for poorly water-soluble drugs. The spray freeze-drying (SFD) method was applied instead of the spray-drying one previously developed. Drug particles were milled in the aqueous solution of dispersing agents using an oscillating beads-milling apparatus. The milled nanosuspension was sprayed to the surface of liquid nitrogen, and the resultant iced droplets were freeze-dried to obtain the powdery product. The loading ratio of a dispersing agent was investigated to enhance its redispersing property. Dry nanosuspension, which could be spontaneously dispersed into original nanosuspension in water, was obtained by SFD process. It was assumed that self dispersion property would be attributed to its structure with porous network, in which the primary milled drug crystals were embedded. Such unique structure contributed greatly to immediate release behaviors of the drug in gastrointestinal buffered media. These pharmaceutical properties were enhanced by increasing the ratio of the dispersing agent to the drug and the solid content in suspension to be sprayed. The present technique via wet milling and spray freeze-drying processes would be a novel dissolution-enhanced technology for poorly water-soluble drugs.

  15. Impacts of grass removal on wetting and actual water repellency in a sandy soil

    Directory of Open Access Journals (Sweden)

    Oostindie Klaas

    2017-03-01

    Full Text Available Soil water content and actual water repellency were assessed for soil profiles at two sites in a bare and grasscovered plot of a sand pasture, to investigate the impact of the grass removal on both properties. The soil of the plots was sampled six times in vertical transects to a depth of 33 cm between 23 May and 7 October 2002. On each sampling date the soil water contents were measured and the persistence of actual water repellency was determined of field-moist samples. Considerably higher soil water contents were found in the bare versus the grass-covered plots. These alterations are caused by differences between evaporation and transpiration rates across the plots. Noteworthy are the often excessive differences in soil water content at depths of 10 to 30 cm between the bare and grass-covered plots. These differences are a consequence of water uptake by the roots in the grass-covered plots. The water storage in the upper 19 cm of the bare soil was at least two times greater than in the grass-covered soil during dry periods. A major part of the soil profile in the grass-covered plots exhibited extreme water repellency to a depth of 19 cm on all sampling dates, while the soil profile of the bare plots was completely wettable on eight of the twelve sampling dates. Significant differences in persistence of actual water repellency were found between the grass-covered and bare plots.

  16. Water-oil drainage dynamics in oil-wet random microfluidic porous media analogs

    CERN Document Server

    Xu, Wei; Neeves, Keith; Yin, Xiaolong

    2012-01-01

    Displacement experiments carried out in microfluidic porous media analogs show that reduced surface tension leads to a more stable displacement, opposite to the process in Hele-Shaw cells where surface tension stabilizes the displacement of a more viscous fluid by a less viscous fluid. In addition, geometry of porous media is observed to play an important role. Three random microfluidic porous media analogs were made to study water-oil drainage dynamics, featuring a pattern of randomly connected channels with a uniform width, a pattern with Gaussian channel width distribution, and a pattern with large isolated pores. The microfluidic chips fabricated using Polydimenthylsiloxane with glass covers have the internal surface treated by Trichlorosilane to achieve a uniform oil-wet condition. The aqueous phase displaces the oil phase, with a viscosity ratio of about 1:40 and a density ratio of 1:0.85. Videos 1-3 show water flooding processes. It is observed that both channel size distribution (Video 2) and heteroge...

  17. WET MARS: Plentiful, Readily-Available Martian Water and its Implications

    Energy Technology Data Exchange (ETDEWEB)

    Hyde, R.; Ishikawa, M.; Nuckolls, J.; Whitehead, J.; Wood, L.

    1999-09-14

    /oxygen/fuel plant exploiting Martian atmospheric water. All of the oxygen, water and propellants necessary for life-support, extensive exploration and Earth-return can be provided readily by the host planet. Crewed exploration of Mars launched from LEO with on1.V 2 Shuttle-loads of equipment and consumables--a commercial total cost-equivalent of {approx}$650 M--thereby becomes feasible. The most challenging current problem with respect to human expeditions to Mars is escape from Earth's deep, 11.2 km/s gravity well, and is largely an economic issue. Living on Mars, exploring it extensively and returning to Earth, each hitherto major technical issues, are actually much less difficult, thanks in no small part to the effective ''wetness'' of Mars. Similar considerations apply to other water-rich locations in the Solar system, e.g. Europa.

  18. Wetting property of smooth and textured hydrophobic surfaces under condensation condition

    Science.gov (United States)

    Hao, PengFei; Lv, CunJing; Yao, ZhaoHui; Niu, FengLei

    2014-11-01

    Static and dynamic wetting behaviors of sessile droplet on smooth, microstructured and micro/nanostructured surface under condensation condition are systematically studied. In contrast to the conventional droplet wetting on such natural materials by dropping, we demonstrate here that when dropwise condensation occurs, the sessile droplet will transit from the Cassie-Baxter wetting state to the Wenzel wetting state or partial Cassie-Baxter wetting state on the microstructured surface or the micro/nanostructured surface, which leads to a strong adhesion between the droplet and the substrate. In contrast, the apparent contact angle and the sliding angle on the smooth surface changes a little before and after the condensation because of small roughness. Theoretical analysis shows that the roughness factor controls the adhesion force of the droplet during condensation, and a theoretical model is constructed which will be helpful for us to understand the relationship between the adhesion force and the geometry of the surface.

  19. Wet-spinnability and crosslinked fibre properties of two collagen polypeptides with varied molecular weight

    CERN Document Server

    Tronci, Giuseppe; Arafat, M Tarik; Yin, Jie; Wood, David J; Russell, Stephen J

    2015-01-01

    The formation of naturally-derived materials with wet stable fibrous architectures is paramount in order to mimic the features of tissues at the molecular and microscopic scale. Here, we investigated the formation of wet-spun fibres based on collagen-derived polypeptides with comparable chemical composition and varied molecular weight. Gelatin and hydrolysed fish collagen (HFC) were selected as widely-available linear amino-acidic chains of high and low molecular weight, respectively, and functionalised in the wet-spun fibre state in order to preserve the material geometry in physiological conditions. Wet-spun fibre diameter and morphology were dramatically affected depending on the polypeptide molecular weight, wet-spinning solvent (i.e. 2,2,2-Trifluoroethanol and dimethyl sulfoxide) and coagulating medium (i.e. acetone and ethanol), resulting in either bulky or porous internal geometry. Dry-state tensile moduli were significantly enhanced in gelatin and HFC samples following covalent crosslinking with activ...

  20. Effects of Revolution on soil wetting, turf performance and nitrogen efficiency of a fairway prone to soil water repellency

    NARCIS (Netherlands)

    Oostindie, K.; Dekker, L.W.; Geissen, V.; Ritsema, C.J.

    2013-01-01

    This study reports on the effects of applications of the surfactant Revolution on soil wetting and turf performance of fairway 10 of the Rosendaelsche Golfclub, located near Arnhem, The Netherlands. In addition, the influence of Revolution on soil water repellency and the nitrogen contents in grass

  1. The Effect of Non-Uniform Wetting Properties on Contact Line Dynamics

    Science.gov (United States)

    Grivel, Morgane; Jeon, David; Gharib, Morteza

    2015-11-01

    Surfaces with non-uniform wetting properties have been shown to modify contact line dynamics and induce passive displacements of shallow flows. These surfaces are patterned with alternating hydrophobic and hydrophilic stripes of a certain width, spacing and orientation. A thin rectangular wall jet impinges on the surfaces and Fourier Transform Profilometry is used to reconstruct the 3D profile of the low to medium Reynolds number flows. Our previous work reported the development of intriguing roller structures at the contact line near hydrophobic-hydrophilic interfaces and the effect of varying the stripes' dimensions and orientation on these flows. Our present work extends the study to the effects of flow rate and plate inclination angle (with respect to the horizontal). The current work also studies air entrainment by the roller structures of the modified contact line. We will also discuss potential uses of this technique for modifying contact line dynamics and bow waves near surface-piercing bodies. Work is funded by the Office of Naval Research (grant N00014-11-1-0031) and the National Science Foundation's GRFP.

  2. Observation of interactions between hydrophilic ionic liquid and water on wet agar gels by FE-SEM and its mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Chisato; Shirai, Takashi [Ceramics Research Laboratory, Nagoya Institute of Technology, 3-101-1, Honmachi, Tajimi, Gifu 507-0033 (Japan); Fuji, Masayoshi, E-mail: fuji@nitech.ac.jp [Ceramics Research Laboratory, Nagoya Institute of Technology, 3-101-1, Honmachi, Tajimi, Gifu 507-0033 (Japan)

    2012-03-15

    Highlights: Black-Right-Pointing-Pointer The mechanism of SEM observation of agar gel using ionic liquid was investigated. Black-Right-Pointing-Pointer Weak hydrogen bond between ionic liquid and water exist even under vacuum condition. Black-Right-Pointing-Pointer Ionic liquid binding ability with water is useful for observing wet material using FE-SEM. Black-Right-Pointing-Pointer We could optimize the water concentrations of sample of IL and wet material mixtures. Black-Right-Pointing-Pointer SEM observation of fine morphology of agar gel in optimum water content. - Abstract: In the present study, an attempt is made to understand the mechanism of field emission electron microscopy (FE-SEM) observation of wet agar gel using a typical hydrophilic ionic liquid (IL) 1-butyl-3-methylimidazolium tetrafluoroborate; [BMIM][BF{sub 4}]. The IL interaction with water molecules within agar gel during sample preparation condition for FE-SEM observation was investigated using Raman spectroscopy. Results showed that water molecules within agar gel form weak hydrogen bond such as BF{sub 4}{sup -} Midline-Horizontal-Ellipsis HOH Midline-Horizontal-Ellipsis BF{sub 4}{sup -} by interaction with BF{sub 4}{sup -} of IL, and, it remained stable even under vacuum condition at 60 Degree-Sign C, 24 h. This interaction was found to be helpful for IL displacement of the water molecules within agar gel. From this study, it was found that the exact morphology of gel materials in FE-SEM condition can be observed by optimization of water concentrations of IL and gel mixtures. Thus, using IL, agar gel or any other material under wet condition can be observed without drying in FE-SEM chamber, and, present result gives an insight to the mechanism of FE-SEM observation of agar gel using IL without any conducting coating.

  3. Influence of wet activation of used inorganic binder on cyclically refreshed water glass moulding sands hardened by microwaves

    OpenAIRE

    Mateusz Stachowicz; Kazimierz Granat

    2016-01-01

    The paper presents the research results of using an innovative method to reclaim the waste moulding sands containing water glass. Two of the examined processes are connected with "dry" or "wet" activation of inorganic binder in waste moulding sand mixtures physically hardened by microwave radiation. The sand mixtures consisting of high-silica sand and water-glass with average molar module 2.5, were subjected to the following cyclical process: mixing the components, compacting, microwave heati...

  4. Octagon to Square Wetting Area Transition of Water-Ethanol Droplets on a Micropyramid Substrate by Increasing Ethanol Concentration.

    Science.gov (United States)

    Feng, Huicheng; Chong, Karen Siew-Ling; Ong, Kian-Soo; Duan, Fei

    2017-02-07

    The wettability and evaporation of water-ethanol binary droplets on the substrate with micropyramid cavities are studied by controlling the initial ethanol concentrations. The droplets form octagonal initial wetting areas on the substrate. As the ethanol concentration increases, the side ratio of the initial wetting octagon increases from 1.5 at 0% ethanol concentration to 3.5 at 30% ethanol concentration. The increasing side ratio indicates that the wetting area transforms from an octagon to a square if we consider the octagon to be a square with its four corners cut. The droplets experience a pinning-depinning transition during evaporation. The pure water sessile droplet evaporation demonstrates three stages from the constant contact line (CCL) stage, and then the constant contact angle (CCA) stage, to the mixed stage. An additional mixed stage is found between the CCL and CCA stages in the evaporation of water-ethanol binary droplets due to the anisotropic depinning along the two different axes of symmetry of the octagonal wetting area. Droplet depinning occurs earlier on the patterned surface as the ethanol concentration increases.

  5. Effect of coagulation temperature on structures and properties of poly(p-phenylene benzobisoxazole) (DHPBO) fibers during dry-jet wet-spinning process

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The effect of coagulation temperature on the morphology, microstructures and mechanical properties of dihydroxy poly(p-phenylene benzobisoxazole) (DHPBO) fibers was investigated during dry-jet wet- spinning process, in which the coagulation bath concentration and drawn ratio were kept as 10 wt% of PPA in water and 1.7, respectively. The structures and mechanical properties of the as-spun DHPBO fibers were characterized by FTIR, XRD, SEM, and single fiber tensile testing. The results indicated that in PPA/H2O coagulation system, when the coagulation temperature was 25℃, highly crystallized DHPBO as-spun fibers possessing fine crystallites, circular and smooth morphology, and excellent mechanical properties could be achieved.

  6. Wet, Dry, Dim, or Bright? The Future of Water Resources in North Texas

    Science.gov (United States)

    Brikowski, T. H.

    2009-12-01

    Future water resource availability in North Texas (Dallas-Ft. Worth Metroplex) is likely to be limited by the combined impact of decadal-scale and longer term climate changes. Two decadal precipitation anomalies are statistically distinguishable in the historical record (dry/wet, Table 1). These correspond temporally with the onset of global dimming/brightening events (hydrologic cycle retardation/acceleration) respectively (Table 1). Surface water hydrologic parameters are variably correlated with these events, depending on the degree of time-integration of each process. Precipitation correlates most strongly with the decadal anomalies. Runoff changes during these periods were magnified relative to precipitation changes, presumably an effect of soil moisture changes, and over the basin as a whole correlate best with the global events. Palmer Drought Severity Index (PDSI) attempts to capture such effects, and also correlates most strongly with the global events. The most important time-integrators of the system, reservoirs, show mixed correlation in terms of total storage with the decadal and longer term climate periods. Reservoir flood releases (excess storage) correlate with decadal precipitation anomalies, in part reflecting short-term consumption influences. Major reservoirs in the area post-date the dry period, precluding direct evaluation of sustainability from historical records. Historical correlations versus PDSI can be combined with climate-model based PDSI projections to evaluate future sustainability. Climate projections based on a mean of 19 IPCC intermediate scenario (SRESa1b) models indicate an approximately 10% reduction in mean annual precipitation, and warming of 2oC by 2050 in this region. Steady lowering of mean annual PDSI results, with a 50% probability that annual PDSI will average -0.5 by 2050. Average climate will move from humid (Aridity Index=35) to semi-humid (AI=27), and runoff can be expected to decline accordingly. Probability of a

  7. The Preliminary Study on the Converting Measures between the Four Waters in Wet and Low-lying Farmland

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Most of China's wetland areas are located in the Sanjiang Plain.This area has 207×104 hm2 of wet and low-lying farmland,of which 59% is cropped.During the 1970s and 1980s,the Chinese government organized intensive scientific research into potential changes to existing natural resources conditions for these farmlands.The aim was to change the water resources regime to one that was beneficial to crop production.Arterial drainage,field drainage and appropriate sub-soil treatments were required.The relation between plant products industry and the Four Waters distribution,also the main measures of the Four Waters converting in wet and low-lying farmland were discussed in the paper.

  8. FILM-30: A Heat Transfer Properties Code for Water Coolant

    Energy Technology Data Exchange (ETDEWEB)

    MARSHALL, THERON D.

    2001-02-01

    A FORTRAN computer code has been written to calculate the heat transfer properties at the wetted perimeter of a coolant channel when provided the bulk water conditions. This computer code is titled FILM-30 and the code calculates its heat transfer properties by using the following correlations: (1) Sieder-Tate: forced convection, (2) Bergles-Rohsenow: onset to nucleate boiling, (3) Bergles-Rohsenow: partially developed nucleate boiling, (4) Araki: fully developed nucleate boiling, (5) Tong-75: critical heat flux (CHF), and (6) Marshall-98: transition boiling. FILM-30 produces output files that provide the heat flux and heat transfer coefficient at the wetted perimeter as a function of temperature. To validate FILM-30, the calculated heat transfer properties were used in finite element analyses to predict internal temperatures for a water-cooled copper mockup under one-sided heating from a rastered electron beam. These predicted temperatures were compared with the measured temperatures from the author's 1994 and 1998 heat transfer experiments. There was excellent agreement between the predicted and experimentally measured temperatures, which confirmed the accuracy of FILM-30 within the experimental range of the tests. FILM-30 can accurately predict the CHF and transition boiling regimes, which is an important advantage over current heat transfer codes. Consequently, FILM-30 is ideal for predicting heat transfer properties for applications that feature high heat fluxes produced by one-sided heating.

  9. Influence of short chain organic acids and bases on the wetting properties and surface energy of submicrometer ceramic powders.

    Science.gov (United States)

    Neirinck, Bram; Soccol, Dimitri; Fransaer, Jan; Van der Biest, Omer; Vleugels, Jef

    2010-08-15

    The effect of short chained organic acids and bases on the surface energy and wetting properties of submicrometer alumina powder was assessed. The surface chemistry of treated powders was determined by means of Diffuse Reflectance Infrared Fourier Transform spectroscopy and compared to untreated powder. The wetting of powders was measured using a modified Washburn method, based on the use of precompacted powder samples. The geometric factor needed to calculate the contact angle was derived from measurements of the porous properties of the powder compacts. Contact angle measurements with several probe liquids before and after modification allowed a theoretical estimation of the surface energy based on the surface tension component theory. Trends in the surface energy components were linked to observations in infrared spectra. The results showed that the hydrophobic character of the precompacted powder depends on both the chain length and polar group of the modifying agent. Copyright 2010 Elsevier Inc. All rights reserved.

  10. Variation in soil water uptake and its effect on plant water status in Juglans regia L. during dry and wet seasons.

    Science.gov (United States)

    Sun, Shou-Jia; Meng, Ping; Zhang, Jin-Song; Wan, Xianchong

    2011-12-01

    Temporal and spatial variations in the water status of walnut trees (Juglans regia L.) and the soil in which they were growing were traced by analyzing the differences in hydrogen isotopes during spring and summer in a 7-year-old walnut stand. Walnut root dynamics were measured in both dry and wet seasons. Walnut roots were mainly distributed in the upper soil (0-30 cm depth), with around 60% of the total root mass in upper soil layers and 40% in deep soil layers (30-80 cm depth). The upper soil layers contributed 68% of the total tree water requirement in the wet season, but only 47% in the dry season. In the wet season, total roots, living roots and new roots were all significantly more abundant than in the dry season. There were significant differences in pre-dawn branch percentage loss of hydraulic conductance (PLC), pre-dawn leaf water potential and transpiration between the dry and wet seasons. Water content in the upper soil layers remarkably influenced xylem water stable-hydrogen isotope (δD) values. Furthermore, there were linear relationships between the xylem water δD value and pre-dawn branch PLC, pre-dawn leaf water potential, transpiration rate and photosynthetic rate. In summary, J. regia was compelled to take a larger amount of water from the deep soil layers in the dry season, but this shift could not prevent water stress in the plant. The xylem water δD values could be used as an indicator to investigate the water stress of plants, besides probing profiles of soil water use.

  11. Structural, optical and photocatalytic properties of flower-like ZnO nanostructures prepared by a facile wet chemical method

    OpenAIRE

    2013-01-01

    Flower-like ZnO nanostructures were synthesized by a facile wet chemical method. Structural, optical and photocatalytic properties of these nanostructures have been studied by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photoluminescence (PL) and UV–vis absorption spectroscopy. SEM and TEM studies revealed flower-like structures consisting of nanosheets, formed due to oriented attachment of ZnO nanoparticles. Flower-like ZnO structures ...

  12. Impacts of Wetting Fly Ash on the Properties of Concrete%湿排粉煤灰对混凝土性能的影响

    Institute of Scientific and Technical Information of China (English)

    吴传明; 钱觉时; 侯鹏坤; 王智; 汪克进; 罗晖

    2009-01-01

    通过实验室模拟研究不同湿法存放时间(1~60个月)的2种低钙粉煤灰的形貌、粒径和用于混凝土掺合料的性能变化.粉煤灰湿排后颗粒变粗,颗粒表面出现侵蚀,但颗粒形貌基本保持不变;湿排粉煤灰矿物减水效应明显降低,掺量为20%~40%的湿排粉煤灰混凝土坍落度比原状粉煤灰混凝土减少约20~40 mm;掺加湿排粉煤灰的混凝土与外加剂适应性、抗渗和抗碳化无明显变化,坍落度经时损失有所降低;湿法存放3个月的粉煤灰掺量20%时混凝土28 d和56 d抗压强度比原状粉煤灰混凝土分别下降5.8%和3.7%,但掺量为20%的湿法存放36个月粉煤灰混凝土抗压强度比仍可以达到85%,湿法存放时间为3 a和5 a的粉煤灰混凝土强度无明显差别.研究结果表明,湿排低钙粉煤灰可以用作为混凝土掺合料.%Two types of wetting low-calcium fly ash were made for studying the performance under different storage time (1 to 60 months). The surface morphology, granule size distribution of the wetting fly ashes and their properties as supplementary cementitious materials in concrete were investigated. Although the granule size increased and there appeared considerable erosion on the surface, the surface morphology of wetting fly ash kept mostly unchangeable. The water reducing effect resulted from mineral properties of fly ash decreased much due to wetting. Compared with a parallel concrete with dry fly ash, slump of concretes with fly ash of 20~40% wetting for 3 months decreased by 20~40 mm while bleeding and permeability and carbonation had no change. The compressive strength of concrete in 28 day and 60 days with fly ash of 30% wetting for 3 months decreased by 5. 8% and 3. 7% respectively. However, the specific compressive strength of concrete in 56 days with fly ash of 20% wetting for 36 months still reached at 85% and there was no visible strength discrepancy of fly ash concrete wetting for 3 and 5 years

  13. Effect of surfactants or a water soluble polymer on the crystal transition of clarithromycin during a wet granulation process.

    Science.gov (United States)

    Nozawa, Kenji; Iwao, Yasunori; Noguchi, Shuji; Itai, Shigeru

    2015-11-10

    To generate products containing a stable form of clarithromycin (CAM) (form II) regardless of the initial crystal form of CAM or type of granulation solvent, the effects of five surfactants, or a water-soluble polymer (macrogol 400) were determined on the crystal transition of CAM. The metastable form (form I) was kneaded with water, after adding surfactants, or a water-soluble polymer. Form II was also kneaded with ethanol, after adding the same additives. The resulting samples were analyzed by powder X-ray diffraction. Form I was completely converted to form II by a wet granulation using water with additives bearing polyoxyethylene chains such as polysorbate 80 (PS80), polyoxyl 40 stearate or macrogol 400. The granulation of the form II using ethanol with these additives did not result in a crystal transition to form I. Furthermore, CAM tablets were manufactured using granules with PS80, and these crystal forms and dissolution behaviors were investigated. As a result, the wet granulation of CAM with PS80 gave CAM tablets containing only form II and PS80 did not have any adverse effects on tablet characteristics. Therefore, these data suggests that the crystal form of CAM can be controlled to be form II using a wet granulation process with additives bearing polyoxyethylene chains regardless of the initial crystal form of CAM or type of granulation solvent. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Wetting property of smooth and textured hydrophobic surfaces under condensation condition

    Institute of Scientific and Technical Information of China (English)

    HAO PengFei; LV CunJing; YAO ZhaoHui; NIU FengLei

    2014-01-01

    Static and dynamic wetting behaviors of sessile droplet on smooth,microstructured and micro/nanostructured surface under condensation condition are systematically studied.In contrast to the conventional droplet wetting on such natural materials by dropping,we demonstrate here that when dropwise condensation occurs,the sessile droplet will transit from the Cassie-Baxter wetting state to the Wenzel wetting state or partial Cassie-Baxter wetting state on the microstructured surface or the micro/nanostructured surface,which leads to a strong adhesion between the droplet and the substrate.In contrast,the apparent contact angle and the sliding angle on the smooth surface changes a little before and after the condensation because of small roughness.Theoretical analysis shows that the roughness factor controls the adhesion force of the droplet during condensation,and a theoretical model is constructed which will be helpful for us to understand the relationship between the adhesion force and the geometry of the surface.

  15. Leaching and antimicrobial properties of silver nanoparticles loaded onto natural zeolite clinoptilolite by ion exchange and wet impregnation.

    Science.gov (United States)

    Missengue, Roland N M; Musyoka, Nicholas M; Madzivire, Godfrey; Babajide, Omotola; Fatoba, Ojo O; Tuffin, Marla; Petrik, Leslie F

    2016-01-28

    This study aimed to compare the leaching and antimicrobial properties of silver that was loaded onto the natural zeolite clinoptilolite by ion exchange and wet impregnation. Silver ions were reduced using sodium borohydride (NaBH4). The leaching of silver from the prepared silver-clinoptilolite (Ag-EHC) nanocomposite samples and their antimicrobial activity on Escherichia coli Epi 300 were investigated. It was observed that the percentage of silver loaded onto EHC depended on the loading procedure and the concentration of silver precursor used. Up to 87% of silver was loaded onto EHC by wet impregnation. The size of synthesized silver nanoparticles varied between 8.71-72.67 nm and 7.93-73.91 nm when silver was loaded by ion exchange and wet impregnation, respectively. The antimicrobial activity of the prepared nanocomposite samples was related to the concentration of silver precursor used, the leaching rate and the size of silver nanoparticles obtained after reduction. However, only in the case of the nanocomposite sample (Ag-WEHC) obtained after loading 43.80 ± 1.90 µg of Ag per gram zeolite through wet impregnation was the leaching rate lower than 0.1 mg L(-1) limit recommended by WHO, with an acceptable microbial killing effect.

  16. Influence of the Surfactants on Microstructure and the Properties of Wet Coagulation Polyurethane Film

    Institute of Scientific and Technical Information of China (English)

    ZENG Yue-min; YAN Hao-jing; HU Jin-lian

    2002-01-01

    Polyurethane asymmetric membranes were prepared bywet coagulation process from the PU/DMF/Span-80/OT-70 solutions, and the morphological features of the cross section of the membranes obtained by scanning electron microscopy were presented. The influences of the non-ionic hydrophobic surfactant Span- 80 and the anionic surfactant hydrophilic OT-70 on the morphology of the membranes, the mechanical properties and the water vapor permeability were studied. The formation mechanism of the membrane microstructure from the different PU/DMF/Surfactants systems was discussed.

  17. The periodic wetting of leaves enhances water relations and growth of the long-lived conifer Araucaria angustifolia.

    Science.gov (United States)

    Cassana, F F; Dillenburg, L R

    2013-01-01

    The importance of foliar absorption of water and atmospheric solutes in conifers was recognised in the 1970s, and the importance of fog as a water source in forest environments has been recently demonstrated. Araucaria angustifolia (Araucariaceae) is an emergent tree species that grows in montane forests of southern Brazil, where rainfall and fog are frequent events, leading to frequent wetting of the leaves. Despite anatomical evidence in favour of leaf water absorption, there is no information on the existence and physiological significance of a such process. In this study, we test the hypothesis that the use of atmospheric water by leaves takes place and is physiologically relevant for the species, by comparing growth, water relations and nutritional status between plants grown under two conditions of soil water (well-watered and water-stressed plants) and three types of leaf spraying (none, water and nutrient solution spray). Leaf spraying had a greater effect in improving plant water relations when plants were under water stress. Plant growth was more responsive to water available to the leaves than to the roots, and was equally increased by both types of leaf spraying, with no interaction with soil water status. Spraying leaves with nutrient solution increased shoot ramification and raised the concentrations of N, P, K, Zn, Cu and Fe in the roots. Our results provide strong indications that water and nutrients are indeed absorbed by leaves of A. angustifolia, and that this process might be as important as water uptake by its roots.

  18. Coarse-graining MARTINI model for molecular-dynamics simulations of the wetting properties of graphitic surfaces with non-ionic, long-chain and T-shaped surfactants

    CERN Document Server

    Sergi, Danilo; Ortona, Alberto

    2012-01-01

    We report on a molecular dynamics investigation of the wetting properties of graphitic surfaces by various solutions at concentrations 1-8 wt% of commercially available non-ionic surfactants with long hydrophilic chains, linear or T-shaped. These are surfactants of length up to 160 [\\AA]. It turns out that molecular dynamics simulations of such systems ask for a number of solvent particles that can be reached without seriously compromising computational efficiency only by employing a coarse-grained model. The MARTINI force field with polarizable water offers a framework particularly suited for our problem. In general, its advantages over other coarse-grained models are the possibility to explore faster long time scales and the wider range of applicability. Although the accuracy is sometimes put under question, the results for the wetting properties by pure water are in good agreement with those for the corresponding atomistic systems and theoretical predictions. On the other hand, the bulk properties of vario...

  19. Fabrication of Nanostructured Polymer Surfaces and Characterization of their Wetting Properties

    DEFF Research Database (Denmark)

    Andersen, Nis Korsgaard

    micro- and nanostructuring of commerical injection molding tools to create the desired surface structures directly in the molding process. The aim of this project was to enable the fabrication of surfaces with controlled wetting by injection molding. During the project, I have demonstrated improvements....... • Simulations of wetting transitions. • Clean room fabrication of functional surfaces, and production of micro- and nanostructured mold inserts. • Injection molding of micro- and nanostructured polymer parts on a commercial injection molding machine. • Co-invented a patented technique for microstructuring steel...

  20. Effects of water re-saturation conditions and associated extractives leaching on thermal softening of wet wood

    OpenAIRE

    BREMAUD, Iris; Bardet, Sandrine; Gril, Joseph; Perré, Patrick

    2014-01-01

    International audience; Thermal softening, or thermo-activated viscoelasticity, is involved in several industrial and/or traditional craftsmanship techniques processing of wood. More fundamentally, it represents a very useful probe of chemical differences and/or of physical histories of wood samples [1,2,3,4,5]. Thermal softening of wet (= water-saturated) wood occurs at much lower temperature than that of completely (anhydrous) dried wood [6,7]. Softening of oven-dry wood happens at temperat...

  1. Wetting and Photocatalytic Properties of TiO2 Nanotube Arrays Prepared via Anodic Oxidation of E-Beam Evaporated Ti Thin Films

    Directory of Open Access Journals (Sweden)

    Soon Wook Kim

    2015-01-01

    Full Text Available TiO2 nanotube arrays (TNAs are fabricated on quartz substrate by anodizing E-beam evaporated Ti films. E-beam evaporated Ti films are directly anodized at various anodizing voltages ranging from 20 to 45 V and their morphological, wetting, and photocatalytic properties are examined. The photocatalytic activity of the prepared TNAs is evaluated by the photodecomposition of methylene blue under UV illumination. The TNAs prepared at an anodizing voltage of 30 V have a high roughness of 30.1 nm and a low water contact angle of 7.5°, resulting in a high photocatalytic performance. The surface roughness of the TNAs is found to correlate inversely with the water contact angle. High roughness (i.e., high surface area, which leads to high hydrophilicity, is desirable for effective photocatalytic activity.

  2. Contact Angles of Water-repellent Porous Media Inferred by Tensiometer- TDR Probe Measurement Under Controlled Wetting and Drying Cycles

    DEFF Research Database (Denmark)

    Subedi, Shaphal; Komatsu, Ken; Komatsu, Toshiko;

    2013-01-01

    The time dependency of water repellency (WR) in hydrophobic porous media plays a crucial role for water infiltration processes after rainfall and for the long-term performance of capillary barrier systems. The contact angle (CA) of hydrophobic media normally decreases with continuous contact...... equipped with a mini-time domain reflectometry (TDR) coil probe under controlled wetting and drying in a water-repellent volcanic ash soil (VAS) and in sands coated with different hydrophobic agents. The contact angle (CA–SWRC) under imbibition was evaluated based on the inflection points on the water...... retention curves. For both water-repellent VAS and hydrophobized sand samples, the calculated CA–SWRC increased with increasing WR. This was determined from both the water drop penetration time and the initial contact angle (CAi) by the sessile drop method. Calculated CA–SWRC values ranged from 20° to 48...

  3. Wetting behavior of water and oil droplets in three-phase interfaces for hydrophobicity/philicity and oleophobicity/philicity.

    Science.gov (United States)

    Jung, Yong Chae; Bhushan, Bharat

    2009-12-15

    Biomimetics, mimicking nature for engineering solutions, provides a model for the development of superhydrophobic/superoleophobic and self-cleaning surfaces. A number of biomimetic superhydrophobic surfaces have been developed by using a hydrophobic coating, surface roughness, and the ability to form air pockets between solid and water. Oleophobic surfaces that have the potential for self-cleaning and antifouling from biological and organic contaminants in both air and water need to be studied. The surface tension of oil and organic liquids is lower than that of water, so to create a superoleophobic surface, the surface energy of the solid surface in air should be lower than that of oil. The wetting behavior of water and oil droplets for hydrophobic/philic and oleophobic/philic surfaces in three-phase interfaces was studied. In order to make the surface oleophobic at a solid-air-oil interface, a material with a surface energy lower than that of oil was used. In underwater applications, the oleophobicity/philicity of an oil droplet in water was studied on the surfaces with different surface energies of various interfaces and contact angles of water and oil droplets in air. A model for predicting the contact angles of water and oil droplets was proposed. To validate the model, the wetting behavior of flat and micropatterned surfaces with varying pitch values were studied. Furthermore, the wetting behavior of the nano- and hierarchical structures found in Lotus plant surfaces and the shark skin replica as an example of aquatic animal were also studied. On the basis of the experimental data and the model, the trends were explained.

  4. Hydroxypropylcellulose controlled release tablet matrix prepared by wet granulation: effect of powder properties and polymer composition

    Directory of Open Access Journals (Sweden)

    Antonio Zenon Antunes Teixeira

    2009-02-01

    Full Text Available The aim of this study was to attain 100% drug release of caffeine after 24 h from hydroxypropylcellulose (HPC tablet matrices and to investigate the effect of co-excipient. Physical properties of the powders were evaluated and suggested for a wet granulation process. The tablet containing caffeine was formulated by different weight ratios of hydrophilic polymers. The results of polymer evaluation confirmed that the increase of HPC level with the same drug content significantly decreased the rate of drug release. The presence of co-polymer excipients carboxymethylcellulose (CMC and polyvinylpyrrolidone (PVP in the tablet matrix was also investigated. The release rate was also controlled by low levels of CMC (O objetivo deste estudo é desenvolver a liberação 100% da droga cafeína em 24 horas em comprimidos matrizes e investigar o uso de hidroxipropilcelulose (HPC mais os efeitos de co-excipiente. As propriedades físicas dos pós foram avaliadas assim como seu uso no processo de granulação úmida. O comprimido contendo a cafeína foi formulado por diferentes relações de peso dos polímeros hidrofílicos. Os resultados da avaliação do polímero confirmaram que o aumento do nível de HPC com o mesmo índice da droga diminuiu significativamente a taxa de liberação da droga. A presença do co-polímero excipiente carboximetilcelulose (CMC e do polivinilpirrolidona (PVP na matriz do comprimido foi também investigado. A taxa de liberação foi controlada principalmente por baixos níveis de CMC (< 10% enquanto PVP não mostrou efeito diferente considerável. A melhor taxa de liberação de cafeína 100% em 24 horas foi obtida quando 10% da lactose monoidrato foi adicionado na formulação.

  5. An investigation into environment dependent nanomechanical properties of shallow water shrimp (Pandalus platyceros) exoskeleton

    Energy Technology Data Exchange (ETDEWEB)

    Verma, Devendra; Tomar, Vikas, E-mail: tomar@purdue.edu

    2014-11-01

    The present investigation focuses on understanding the influence of change from wet to dry environment on nanomechanical properties of shallow water shrimp exoskeleton. Scanning Electron Microscopy (SEM) based measurements suggest that the shrimp exoskeleton has Bouligand structure, a key characteristic of the crustaceans. As expected, wet samples are found to be softer than dry samples. Reduced modulus values of dry samples are found to be 24.90 ± 1.14 GPa as compared to the corresponding values of 3.79 ± 0.69 GPa in the case of wet samples. Hardness values are found to be 0.86 ± 0.06 GPa in the case of dry samples as compared to the corresponding values of 0.17 ± 0.02 GPa in the case of wet samples. In order to simulate the influence of underwater pressure on the exoskeleton strength, constant load creep experiments as a function of wet and dry environments are performed. The switch in deformation mechanism as a function of environment is explained based on the role played by water molecules in assisting interface slip and increased ductility of matrix material in wet environment in comparison to the dry environment. - Highlights: • Environment dependent (dry-wet) properties of shrimp exoskeleton are analyzed. • Mechanical properties are correlated with the structure and composition. • Presence of water leads to lower reduced modulus and hardness. • SEM images shows the Bouligand pattern based structure. • Creep-relaxation of polymer chains, interface slip is high in presence of water.

  6. Asymmetry of agricultural water consumption in arid regions during alternating decadal scale wet and dry periods: explanation using behavioral economics

    Science.gov (United States)

    Tian, Fuqiang

    2017-04-01

    Increase of human water consumption for agriculture and consequent degradation of the ecological environment is a common feature in many arid regions. Understanding the driving mechanisms behind this phenomenon is of critical importance for regional sustainable development. In this study, analyses of temporal patterns of human water consumption are carried out in three hyper-arid inland basins, i.e., Aral Sea Basin in Central Asia, and the Tarim and Heihe River Basins in Northwestern China. Multi-decadal time series of hydrological and human consumption data are divided into decadal sequences of wet and dry years. During the wet phases, the greater water availability inspires economic expansion and human water consumption experiences growth at a rate faster than that of incoming water. During the dry phases, however, the expanded economy (e.g., irrigation land expansion in an agriculture-based economy) has been managed to sustain or even to increase production by over-exploitation of water with sophisticated technologies. Inability to reduce human water consumption at a rate commensurate with the decrease of incoming water supply leads to serious ecosystem degradation. This asymmetric human water consumption response of society to decadal scale hydrologic variability can be explained in terms of prospect theory drawn from behavioral economics, which states that people tend to be risk averse when facing gains and show risk preference when facing losses. In the three socio-hydrological case studies, direct economic gain/loss has relatively low value but high certainty when compared to indirect economic loss/gain (such as environmental or sustainability loss/gain), which has high value but with high uncertainty. According to prospect theory, people tend to gain direct economic benefits at the expense of environmental degradation and at the risk of system collapse. The outcomes of this study have major implications for water resources management at long time scales

  7. Fabrication and durable antibacterial properties of 3D porous wet electrospun RCSC/PCL nanofibrous scaffold with silver nanoparticles

    Science.gov (United States)

    Zhang, Mei; Lin, Han; Wang, -->Yilong; Yang, Guang; Zhao, He; Sun, Dahui

    2017-08-01

    Electrospunnanofibers are used as three-dimensional (3D) scaffold materials that can alter cell attachment and cell proliferation, change the antibacterial properties of materials, and can be used as wound dressings. But the fabrication of porous 3D scaffold structure and the antibacterial properties enhancing are challenges remained to improve. With the states here, a Ranachensinensis skin collagen (RCSC)/poly(ɛ-caprolactone) (PCL)AgNP-loaded3D nanofiber scaffold is fabricated as a wound dressing material by using an improved wet electrospinning method (blending). The nanoscale of the AgNPs is proved. The 3D porous morphologies of the materials with different AgNP loadings, are determined with field emission scanning electron microscopy (FESEM) and the presence and uniformity distribution of AgNPs is confirmed by Energy dispersive X-ray (EDX) spectroscopy. The silver-ion release rates, antibacterial properties, and cytotoxicities of dressing materials with different AgNP contents are evaluated using ICP-AES, the zone inhibition method, and MTT testing. These results showed that the improved wet electrospun is an effective way to fabricate AgNP loaded 3D scaffold materials with porous structure and nearly 90% porosity and the presence of AgNPs in dressing materials strengthen the antibacterial properties. The RCSC/PCL 3D scaffold materials containing 2.0%AgNP would be promising for dressing materials application nearly without cytotoxicities.

  8. Organic solvent wetting properties of UV and plasma treated ZnO nanorods: printed electronics approach

    KAUST Repository

    Sliz, Rafal

    2012-09-13

    Due to low manufacturing costs, printed organic solar cells are on the short-list of renewable and environmentally- friendly energy production technologies of the future. However, electrode materials and each photoactive layer require different techniques and approaches. Printing technologies have attracted considerable attention for organic electronics due to their potentially high volume and low cost processing. A case in point is the interface between the substrate and solution (ink) drop, which is a particularly critical issue for printing quality. In addition, methods such as UV, oxygen and argon plasma treatments have proven suitable to increasing the hydrophilicity of treated surfaces. Among several methods of measuring the ink-substrate interface, the simplest and most reliable is the contact angle method. In terms of nanoscale device applications, zinc oxide (ZnO) has gained popularity, owing to its physical and chemical properties. In particular, there is a growing interest in exploiting the unique properties that the so-called nanorod structure exhibits for future 1-dimensional opto-electronic devices. Applications, such as photodiodes, thin-film transistors, sensors and photo anodes in photovoltaic cells have already been demonstrated. This paper presents the wettability properties of ZnO nanorods treated with UV illumination, oxygen and argon plasma for various periods of time. Since this work concentrates on solar cell applications, four of the most common solutions used in organic solar cell manufacture were tested: P3HT:PCBM DCB, P3HT:PCBM CHB, PEDOT:PSS and water. The achieved results prove that different treatments change the contact angle differently. Moreover, solvent behaviour varied uniquely with the applied treatment. © (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

  9. Organic solvent wetting properties of UV and plasma treated ZnO nanorods: printed electronics approach

    Science.gov (United States)

    Sliz, Rafal; Suzuki, Yuji; Nathan, Arokia; Myllyla, Risto; Jabbour, Ghassan

    2012-09-01

    Due to low manufacturing costs, printed organic solar cells are on the short-list of renewable and environmentally- friendly energy production technologies of the future. However, electrode materials and each photoactive layer require different techniques and approaches. Printing technologies have attracted considerable attention for organic electronics due to their potentially high volume and low cost processing. A case in point is the interface between the substrate and solution (ink) drop, which is a particularly critical issue for printing quality. In addition, methods such as UV, oxygen and argon plasma treatments have proven suitable to increasing the hydrophilicity of treated surfaces. Among several methods of measuring the ink-substrate interface, the simplest and most reliable is the contact angle method. In terms of nanoscale device applications, zinc oxide (ZnO) has gained popularity, owing to its physical and chemical properties. In particular, there is a growing interest in exploiting the unique properties that the so-called nanorod structure exhibits for future 1-dimensional opto-electronic devices. Applications, such as photodiodes, thin-film transistors, sensors and photo anodes in photovoltaic cells have already been demonstrated. This paper presents the wettability properties of ZnO nanorods treated with UV illumination, oxygen and argon plasma for various periods of time. Since this work concentrates on solar cell applications, four of the most common solutions used in organic solar cell manufacture were tested: P3HT:PCBM DCB, P3HT:PCBM CHB, PEDOT:PSS and water. The achieved results prove that different treatments change the contact angle differently. Moreover, solvent behaviour varied uniquely with the applied treatment.

  10. WetNet: Using SSM/I data interactively for global distribution of tropical rainfall and precipitable water

    Science.gov (United States)

    Zipser, Edward J.; Mcguirk, James P.

    1993-01-01

    The research objectives were the following: (1) to use SSM/I to categorize, measure, and parameterize effects of rainfall systems around the globe, especially mesoscale convective systems; (2) to use SSM/I to monitor key components of the global hydrologic cycle, including tropical rainfall and precipitable water, and links to increasing sea surface temperatures; and (3) to assist in the development of efficient methods of exchange of massive satellite data bases and of analysis techniques, especially their use at a university. Numerous tasks have been initiated. First and foremost has been the integration and startup of the WetNet computer system into the TAMU computer network. Scientific activity was infeasible before completion of this activity. Final hardware delivery was not completed until October 1991, after which followed a period of identification and solution of several hardware and software and software problems. Accomplishments representing approximately four months work with the WetNEt system are presented.

  11. Surface properties and wetting behavior of liquid Ag-Sb-Sn alloys

    Directory of Open Access Journals (Sweden)

    Sklyarchuk V.

    2012-01-01

    Full Text Available Surface tension and density measurements of liquid Ag-Sb-Sn alloys were carried out over a wide temperature range by using the sessile drop method. The surface tension experimental data were analyzed by the Butler thermodynamic model in the regular solution approximation. The wetting characteristics of these alloys on Cu and Ni substrates have been also determined. The new experimental results were compared with the calculated values as well as with data available in the literature.

  12. U0{sub 2} pellets surface properties and environmental conditions effects on the wet adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Junqueira, Fabio da S.; Carnaval, Joao Paulo R., E-mail: fabiojunqueira@inb.gov.br, E-mail: joaocarnaval@inb.gov.br [Industrias Nucleares do Brasil S.A. (INB), Resende, Rio de Janeiro, RJ (Brazil)

    2013-07-01

    Angra power plants fuels are made bye en riche uranium dioxide (UO{sub 2}) pellets which are assembled inside metal tubes. These tubes are welded and arranged in order to perform the final product, the fuel assembly. The UO{sub 2} pellets have a specified humidity tolerance designed to comply with security and performance requirements when working under operating conditions in the reactor. This work intends to verify the pellet opened porosity and the environmental conditions (relative humidity and temperature) influence on the wet adsorption by UO{sub 2} pellet. The work was done in 2 parts: Firstly, pallets groups from 3 opened porosity levels were tested under a fixed relative humidity, temperature and time. In the second part of the work, the most critical pallet group upon wet adsorption was tested under different relative humidity and temperature conditions, regarding design of experiments. The opened porosity and environmental conditions tests allowed the evolution of the wet adsorption by the UO{sub 2} pallet. (author)

  13. Influence of wet activation of used inorganic binder on cyclically refreshed water glass moulding sands hardened by microwaves

    Directory of Open Access Journals (Sweden)

    Mateusz Stachowicz

    2016-11-01

    Full Text Available The paper presents the research results of using an innovative method to reclaim the waste moulding sands containing water glass. Two of the examined processes are connected with "dry" or "wet" activation of inorganic binder in waste moulding sand mixtures physically hardened by microwave radiation. The sand mixtures consisting of high-silica sand and water-glass with average molar module 2.5, were subjected to the following cyclical process: mixing the components, compacting, microwave heating, cooling-down, thermally loading the mould to 800 °C, cooling-down to ambient temperature, and knocking-out. After being knocked-out, the waste moulding sands were subjected to either dry or wet activation of the binder. To activate thermally treated inorganic binder, each of the examined processes employed the surface phenomenon usually associated to mechanical reclamation. The study also covered possible use of some elements of wet reclamation to rehydrate waste binder. To evaluate the effectiveness of the two proposed methods of waste binder activation, selected strength and technological parameters were measured. After each subsequent processing cycle, the permeability, tensile strength and bending strength were determined. In addition, the surface of activated sand grains was examined with a scanning electron microscope. Analysis of the results indicates that it is possible to re-activate the used binder such as sodium silicate, and to stabilize the strength parameters in both activation processes. Permeability of the refreshed moulding sands strongly depends on the surface condition of high-silica grains. The wet activation process by wetting and buffering knocked-out moulding sands in closed humid environment makes it possible to reduce the content of refreshing additive in water-glass. The moulding sands cyclically prepared in both processes do not require the addition of fresh high-silica sand. The relatively high quality achieved in the

  14. An investigation into environment dependent nanomechanical properties of shallow water shrimp (Pandalus platyceros) exoskeleton.

    Science.gov (United States)

    Verma, Devendra; Tomar, Vikas

    2014-11-01

    The present investigation focuses on understanding the influence of change from wet to dry environment on nanomechanical properties of shallow water shrimp exoskeleton. Scanning Electron Microscopy (SEM) based measurements suggest that the shrimp exoskeleton has Bouligand structure, a key characteristic of the crustaceans. As expected, wet samples are found to be softer than dry samples. Reduced modulus values of dry samples are found to be 24.90 ± 1.14 GPa as compared to the corresponding values of 3.79 ± 0.69 GPa in the case of wet samples. Hardness values are found to be 0.86 ± 0.06 GPa in the case of dry samples as compared to the corresponding values of 0.17 ± 0.02 GPa in the case of wet samples. In order to simulate the influence of underwater pressure on the exoskeleton strength, constant load creep experiments as a function of wet and dry environments are performed. The switch in deformation mechanism as a function of environment is explained based on the role played by water molecules in assisting interface slip and increased ductility of matrix material in wet environment in comparison to the dry environment.

  15. Contribution of water-limited regions to their own supply of rainfall during wet and dry years

    Science.gov (United States)

    Miralles, Diego; Nieto, Raquel; McDowell, Nathan; Dorigo, Wouter; Verhoest, Niko; Liu, Yi; Teuling, Adriaan; Dolman, Han; Good, Stephen; Gimeno, Luis

    2017-04-01

    The occurrence of wet and dry spells in water-limited regions remains poorly understood. When these precipitation anomalies happen during the growing season, they can impact carbon and water budgets and hinder the regional management of natural resources. The difficulties to understand and predict these anomalies are partly owed to the complex role that water-limited ecoregions play in the genesis of their own rainfall: the increases in biomass and transpiration during the growing season are expected to influence the local input of rainfall. In this presentation, we unravel the origin and immediate drivers of growing-season rainfall in the ten major water-limited ecoregions on Earth. We use novel satellite data of vegetation water content and transpiration, combined with Langrangian atmospheric trajectory modelling. The extent to which these ecoregions themselves contribute to their own supply of rainfall is analyzed for dry and wet years separately. Results show that persistent anomalies in growing-season precipitation—and subsequent biomass impacts—are caused by a complex interplay of anomalies in land and ocean evaporation, air circulation and local atmospheric stability. Nonetheless, the specific drivers vary depending on the region of interest. For instance, in Kalahari and Australia, local atmospheric instability and evaporation in the surrounding regions play a central role. In these regions, the volumes of moisture recycling decline in dry years, providing an overall positive feedback that intensifies dry conditions. Despite these declines in the volumes of recycled rainfall, recycling ratios increase over 40% during dry times. This implies that transpiration in periods of water stress partly offsets the decreases in incoming precipitation that are mainly triggered by external conditions. Findings highlight the need to adequately represent vegetation-atmosphere feedbacks in models to predict biomass changes and simulate the fate of water-limited regions

  16. Field performance of alternate wetting and drying furrow irrigation on tomato crop growth, yield, water use efifciency, quality and proiftability

    Institute of Scientific and Technical Information of China (English)

    Khokan Kumer Sarker; M A R Akanda; S K Biswas; D K Roy; A Khatun; M A Goffar

    2016-01-01

    Sustainable irrigation method is now essential for adaptation and adoption in the areas where water resources are limited. Therefore, a ifeld experiment was conducted to test the performance of alternate wetting and drying furrow irrigation (AWDFI) on crop growth, yield, water use efifciency (WUE), fruit quality and proiftability analysis of tomato. The experiment was laid out in randomized complete block design with six treatments replicated thrice during the dry seasons of 2013-2014 and 2014-2015. Irrigation water was applied through three ways of furrow: AWDFI, ifxed wetting and drying furrow irrigation (FWDFI) and traditional (every) furrow irrigation (TFI). Each irrigation method was divided into two levels: irrigation up to 100 and 80% ifeld capacity (FC). Results showed that plant biomass (dry matter) and marketable fruit yield of tomato did not differ signiifcantly between the treatments of AWDFI and TFI, but signiifcant difference was observed in AWDFI and in TFI compared to FWDFI at same irrigation level. AWDFI saved irrigation water by 35 to 38% for the irrigation levels up to 80 and 100% FC, compared to the TFI, respectively. AWDFI improved WUE by around 37 to 40% compared to TFI when irrigated with 100 and 80% FC, respectively. Fruit quality (total soluble solids and pulp) was found greater in AWDFI than in TFI. Net return from AWDFI technique was found nearly similar compared to TFI and more than FWDFI. The beneift cost ratio was viewed higher in AWDFI than in TFI and FWDFI by 2.8, 8.7 and 11, 10.4% when irrigation water was applied up to 100 and 80% FC, respectively. Unit production cost was obtained lower in AWDFI compared to TFI and FWDFI. However, AWDFI is a useful water-saving furrow irrigation technique which may resolve as an alternative choice compared with TFI in the areas where available water and supply methods are limited to irrigation.

  17. Fabrication of Nanostructured Polymer Surfaces and Characterization of their Wetting Properties

    DEFF Research Database (Denmark)

    Andersen, Nis Korsgaard

    molds able to produce superhydrophobic polymer parts. The patented microstructuring technique generates microstructures similar to those found on the leaf of the lotus flower, without the overlaying nanostructure. Despite the lack of hierarchical structures, the microstructured surface shows excellent....... • Simulations of wetting transitions. • Clean room fabrication of functional surfaces, and production of micro- and nanostructured mold inserts. • Injection molding of micro- and nanostructured polymer parts on a commercial injection molding machine. • Co-invented a patented technique for microstructuring steel...

  18. The method of neutron imaging as a tool for the study of the dynamics of water movement in wet aramid-based ballistic body armour panels

    Science.gov (United States)

    Reifler, Felix A.; Lehmann, Eberhard H.; Frei, Gabriel; May, Hans; Rossi, René

    2006-07-01

    A new non-destructive method based on neutron imaging (neutron radiography) to determine the exact water content in aramid-based soft body armour panels is presented. While investigating the ballistic resistance of aramid-based body armour panels under a wet condition, it is important to precisely determine their water content and its chronological development. Using the presented method, the influence of water amount and location on impact testing as well as its time dependence was shown. In the ballistic panels used, spreading of water strongly depended on the kind of quilting. Very fast water migration could be observed when the panels were held vertically. Some first results regarding the water distribution in wet panels immediately after the impact are presented. On the basis of the presented results, requirements for a standard for testing the performance of ballistic panels in the wet state are deduced.

  19. Nitrogen chemistry in surface waters and wet deposition at high altitude in the Sagarmatha (Mt Everest) National Park.

    Science.gov (United States)

    Balestrini, R.; Polesello, S.; Rusconi, M.

    2012-04-01

    The knowledge of the nitrogen cycle is mainly based on studies conducted in relatively human-altered zones located in the north-western hemisphere. Therefore it is of great interest to identify the limits of natural variations of nitrogen in ecosystems that have not experienced the nitrogen pollution, and have undergone minor alterations from human activities. Among the alpine environments of the world, the region of Mount Everest, is a unique ecosystem with a degree of biodiversity among the highest existing, but characterized by a recognized fragility and low resilience. The extreme climate, the slow growing seasons and the thin soils make this ecosystem very sensitive to any environmental change. A yearly sampling campaign was conducted in the Sagarmatha National Park (Nepal) during the monsoon season in 2008 to collect surface water samples at high elevation from 4300 to 5500 m asl. In addition during 2007 and 2008 the sampling of wet deposition was carried on at 5050 m asl at the Nepal Climate Observatory - Pyramid ABC site. The nitrate concentration in the running waters fell in the lower range of the values reported for comparable environments in Europe. As well, the wet deposition load of nitrogen was remarkable lower than those observed in high elevation areas in Europe and North America. A comparison among running waters, precipitations and small lakes, located in the same area, revealed significant higher nitrate concentrations in running waters compared to the other two matrixes. Conversely, ammonia level resulted higher in the rain compared to surface waters. The spatial and temporal variation of the chemical species in running waters were analyzed taking in account the use of soil in the basins and the hydrological regime.

  20. Additives affecting properties of β-Li2TiO3 pebbles in a modified indirect wet chemistry process

    Science.gov (United States)

    Yu, Cheng-Long; Liu, Wei; Yang, Long-Tao; Wang, Dao-Yi; Wu, Kang; Zhang, Zeng-Ping; Wang, Xiu-Feng; Yanagisawa, Kazumichi

    2016-11-01

    Lithium metatitanate (β-Li2TiO3) pebbles were fabricated via the modified indirect wet chemistry method. Effect of varied additives, as polyvinyl alcohol, glycerol, and agar on the properties evolution was investigated. The highest density is obtained by adding 2 wt% (weight percent) polyvinyl alcohol, 3 wt% glycerol, and 3 wt% agar, respectively. β-Li2TiO3 pebbles with relative sintered density of 92.4%T.D. (Theoretical Density), the ratio of the intensity of diffraction peak (002) to that of (-133) of about 2.93, about 1.58 mm in diameter, a better sphericity of 1.02, the particle size of 5-6 μm, and the well-developed surface layered structure are successfully fabricated with 3 wt% glycerol. Glycerol is beneficial to improving the properties by other fabrication method as well.

  1. Evaluation of Empirical Tropospheric Models Using Satellite-Tracking Tropospheric Wet Delays with Water Vapor Radiometer at Tongji, China.

    Science.gov (United States)

    Wang, Miaomiao; Li, Bofeng

    2016-02-02

    An empirical tropospheric delay model, together with a mapping function, is commonly used to correct the tropospheric errors in global navigation satellite system (GNSS) processing. As is well-known, the accuracy of tropospheric delay models relies mainly on the correction efficiency for tropospheric wet delays. In this paper, we evaluate the accuracy of three tropospheric delay models, together with five mapping functions in wet delays calculation. The evaluations are conducted by comparing their slant wet delays with those measured by water vapor radiometer based on its satellite-tracking function (collected data with large liquid water path is removed). For all 15 combinations of three tropospheric models and five mapping functions, their accuracies as a function of elevation are statistically analyzed by using nine-day data in two scenarios, with and without meteorological data. The results show that (1) no matter with or without meteorological data, there is no practical difference between mapping functions, i.e., Chao, Ifadis, Vienna Mapping Function 1 (VMF1), Niell Mapping Function (NMF), and MTT Mapping Function (MTT); (2) without meteorological data, the UNB3 is much better than Saastamoinen and Hopfield models, while the Saastamoinen model performed slightly better than the Hopfield model; (3) with meteorological data, the accuracies of all three tropospheric delay models are improved to be comparable, especially for lower elevations. In addition, the kinematic precise point positioning where no parameter is set up for tropospheric delay modification is conducted to further evaluate the performance of tropospheric delay models in positioning accuracy. It is shown that the UNB3 model is best and can achieve about 10 cm accuracy for the N and E coordinate component while 20 cm accuracy for the U coordinate component no matter the meteorological data is available or not. This accuracy can be obtained by the Saastamoinen model only when meteorological data is

  2. Evaluation of Empirical Tropospheric Models Using Satellite-Tracking Tropospheric Wet Delays with Water Vapor Radiometer at Tongji, China

    Directory of Open Access Journals (Sweden)

    Miaomiao Wang

    2016-02-01

    Full Text Available An empirical tropospheric delay model, together with a mapping function, is commonly used to correct the tropospheric errors in global navigation satellite system (GNSS processing. As is well-known, the accuracy of tropospheric delay models relies mainly on the correction efficiency for tropospheric wet delays. In this paper, we evaluate the accuracy of three tropospheric delay models, together with five mapping functions in wet delays calculation. The evaluations are conducted by comparing their slant wet delays with those measured by water vapor radiometer based on its satellite-tracking function (collected data with large liquid water path is removed. For all 15 combinations of three tropospheric models and five mapping functions, their accuracies as a function of elevation are statistically analyzed by using nine-day data in two scenarios, with and without meteorological data. The results show that (1 no matter with or without meteorological data, there is no practical difference between mapping functions, i.e., Chao, Ifadis, Vienna Mapping Function 1 (VMF1, Niell Mapping Function (NMF, and MTT Mapping Function (MTT; (2 without meteorological data, the UNB3 is much better than Saastamoinen and Hopfield models, while the Saastamoinen model performed slightly better than the Hopfield model; (3 with meteorological data, the accuracies of all three tropospheric delay models are improved to be comparable, especially for lower elevations. In addition, the kinematic precise point positioning where no parameter is set up for tropospheric delay modification is conducted to further evaluate the performance of tropospheric delay models in positioning accuracy. It is shown that the UNB3 model is best and can achieve about 10 cm accuracy for the N and E coordinate component while 20 cm accuracy for the U coordinate component no matter the meteorological data is available or not. This accuracy can be obtained by the Saastamoinen model only when

  3. Well-balanced bicharacteristic-based scheme for multilayer shallow water flows including wet/dry fronts

    Science.gov (United States)

    Dudzinski, M.; Lukáčová-Medvid'ová, M.

    2013-02-01

    The aim of this paper is to present a new well-balanced finite volume scheme for two-dimensional multilayer shallow water flows including wet/dry fronts. The ideas, presented here for the two-layer model, can be generalized to a multilayer case in a straightforward way. The method developed here is constructed in the framework of the Finite Volume Evolution Galerkin (FVEG) schemes. The FVEG methods couple a finite volume formulation with evolution operators. The latter are constructed using the bicharacteristics of multidimensional hyperbolic systems. However, in the case of multilayer shallow water flows the required eigenstructure of the underlying equations is not readily available. Thus we approximate the evolution operators numerically. This approximation procedure can be used for arbitrary hyperbolic systems. We derive a well-balanced approximation of the evolution operators and prove that the FVEG scheme is well-balanced for the multilayer lake at rest states even in the presence of wet/dry fronts. Several numerical experiments confirm the reliability and efficiency of the new well-balanced FVEG scheme.

  4. Wet oxidation of quinoline

    DEFF Research Database (Denmark)

    Thomsen, A.B.; Kilen, H.H.

    1998-01-01

    The influence of oxygen pressure (0.4 and 2 MPa). reaction time (30 and 60 min) and temperature (260 and 280 degrees C) on the wet oxidation of quinoline has been studied. The dominant parameters for the decomposition of quinoline were oxygen pressure and reaction temperature. whereas the reaction...... time was less important within the range studied. Nitrifying bacteria were used to measure the inhibition from wet oxidative-treated samples to study the effect of the (wet oxidation) reaction conditions. Wet oxidation made quinoline more toxic to Nitrosomonas. This was observed for Nitrobacter as well....... The combined wet oxidation and biological treatment of reaction products resulted in 91% oxidation of the parent compound to CO2 and water. Following combined wet oxidation and biological treatment the sample showed low toxicity towards Nitrosomonas and no toxicity towards Nitrobacter. (C) 1998 Elsevier...

  5. Analysis of the effects of wet and dry seasons on a Mediterranean river basin: consequences for coastal waters and its quality management

    OpenAIRE

    Sebastiá Frasquet, María Teresa; Rodilla Alamá, Miguel; Falco Giaccaglia, Silvia Laura; Sanchís Blay, José Andrés

    2013-01-01

    Rivers play a major role in the delivery of nutrients to coastal ecosystems which are essential for ecosystem productivity. However, the increase of nutrients due to anthropogenic activities can cause eutrophication problems. This study analyzes the seasonal variation of phytoplankton communities in the coastal receiving waters of a Mediterranean river. Two scenarios are compared: the wet and the dry season with distinctive characteristics. During the wet season agricultural runoff and combin...

  6. Effect of Boric Acid Concentration on Viscosity of Slag and Property of Weld Metal Obtained from Underwater Wet Welding

    Science.gov (United States)

    Guo, Ning; Guo, Wei; Xu, Changsheng; Du, Yongpeng; Feng, Jicai

    2015-06-01

    Underwater wet welding is a crucial repair and maintenance technology for nuclear plant. A boric acid environment raises a new challenge for the underwater welding maintenance of nuclear plant. This paper places emphasis on studying the influence of a boric acid environment in nuclear plant on the underwater welding process. Several groups of underwater wet welding experiments have been conducted in boric acid aqueous solution with different concentration (0-35000 ppm). The viscosity of the welding slag and the mechanical properties of welds, such as the hardness, strength, and elongation, have been studied. The results show that with increasing boric acid concentration, the viscosity of the slag decreases first and then increases at a lower temperature (less than 1441 °C). However, when the temperature is above 1480 °C, the differences between the viscosity measurements become less pronounced, and the viscosity tends to a constant value. The hardness and ductility of the joints can be enhanced significantly, and the maximum strength of the weld metal can be reached at 2300 ppm.

  7. Wetting of potassium surfaces by superfluid 4He: A study using variational properties of the chemical potential

    Science.gov (United States)

    Szybisz, Leszek

    2000-08-01

    The wetting of planar surfaces of K by superfluid 4He films at T=0 K is theoretically studied. In order to examine the consistency of numerical results, new variational properties of the chemical potential μ are derived. Two substrate-adsorbate interactions are analyzed: (a) the standard ``3-9'' one and (b) the more elaborated potential recently proposed by Chizmeshya, Cole, and Zaremba (CCZ). New results calculated within the framework of two different nonlocal density functionals (namely, those known as the Orsay-Paris and Orsay-Trento formalisms) are reported. It is demonstrated that the numerical solutions obtained from the theoretical equations verify with high accuracy the derived variational conditions. The main output of this investigation is the finding that, for both analyzed adsorption potentials, thick enough helium films exhibit a positive square of the third-sound velocity. The wetting of a potassium substrate by superfluid 4He at T=0 K suggested by experimental data is guaranteed in the case of the recent CCZ potential.

  8. Linear and nonlinear optical properties of functionalized CdSe quantum dots prepared by plasma sputtering and wet chemistry.

    Science.gov (United States)

    Humbert, Christophe; Dahi, Abdellatif; Dalstein, Laetitia; Busson, Bertrand; Lismont, Marjorie; Colson, Pierre; Dreesen, Laurent

    2015-05-01

    We develop an innovative manufacturing process, based on radio-frequency magnetron sputtering (RFMS), to prepare neat CdSe quantum dots (QDs) on glass and silicon substrates and further chemically functionalize them. In order to validate the fabrication protocol, their optical properties are compared with those of QDs obtained from commercial solutions and deposited by wet chemistry on the substrates. Firstly, AFM measurements attest that nano-objects with a mean diameter around 13 nm are located on the substrate after RFMS treatment. Secondly, the UV-Vis absorption study of this deposited layer shows a specific optical absorption band, located at 550 nm, which is related to a discrete energy level of QDs. Thirdly, by using two-color sum-frequency generation (2C-SFG) nonlinear optical spectroscopy, we show experimentally the functionalization efficiency of the RFMS CdSe QDs layer with thiol derived molecules, which is not possible on the QDs layer prepared by wet chemistry due to the surfactant molecules from the native solution. Finally, 2C-SFG spectroscopy, performed at different visible wavelengths, highlights modifications of the vibration mode shape whatever the QDs deposition method, which is correlated to the discrete energy level of the QDs.

  9. Properties of Ceramic Fiber and Ceramic Shot in Wet-laid Processes

    Institute of Scientific and Technical Information of China (English)

    CHENG Long-di

    2002-01-01

    The paper deals with the different sinking properties of ceramic fiber and the ceramic shot in wetlaid nonwoven processes. The difference between the sinking properties of the fiber and the shot is very great according to theory analysis and the test. From results of calculating and practical testing, the method of removing ceramic shots during manufacturing is put forward.

  10. Dynamic behavior of water droplet impact on microtextured surfaces: the effect of geometrical parameters on anisotropic wetting and the maximum spreading diameter.

    Science.gov (United States)

    Li, Xiying; Mao, Liqun; Ma, Xuehu

    2013-01-29

    Textured silicon surfaces decorated by square arrays of pillars with adjustable pitch were fabricated. The wetting behavior, especially for direction-dependent water contact angles on textured silicon surfaces after silanization, was investigated by incorporating the contact line fraction into a modified Wenzel model. Also, the effect of geometrical parameters on the anisotropic wetting behavior of water was examined with respect to water droplet impact on the textured surface. Moreover, the maximum spreading factor was studied theoretically in terms of energy conservation, allowing for surface topography and viscous friction of the liquid flowing among the arrays of the posts. Theoretical models were found to be in good agreement with experimental data.

  11. Wetting Properties of Liquid Lithium on Stainless Steel and Enhanced Stainless Steel Surfaces

    Science.gov (United States)

    Fiflis, P.; Xu, W.; Raman, P.; Andruczyk, D.; Ruzic, D. N.; Curreli, D.

    2012-10-01

    Research into lithium as a first wall material has proven its ability to effectively getter impurities and reduce recycling of hydrogen ions at the wall. Current schemes for introducing lithium into a fusion device consist of lithium evaporators, however, as these devices evolve from pulsed to steady state, new methods will need to be employed such as the LIMIT concept of UIUC, or thin flowing film lithium walls. Critical to their implementation is understanding the interactions of liquid lithium with various surfaces. One such interaction is the wetting of materials by lithium, which may be characterized by the contact angle between the lithium and the surface. Experiments have been performed at UIUC into the contact angle of liquid lithium with a given surface, as well as methods to increase it. To reduce the oxidation rate of the droplets, the experiments were performed in vacuum, using a lithium injector to deposit drops on each surface. Among the materials investigated are stainless steel, both untreated and coated with a diamond like carbon (DLC) layer, molybdenum, and boronized molybdenum. The contact angle and its dependence on temperature is measured.

  12. Effect of Wet Surface Treated Nano-SiO2 on Mechanical Properties of Polypropylene Composite

    Institute of Scientific and Technical Information of China (English)

    WANG Dongbo; FENG Yujie; HAN Liwei; TIAN Yan

    2008-01-01

    Nano-SiO2/polypropylene composite was prepared by melt-blending process. The nano-SiO2 particles were organized by wet process surface treatment with silane coupling agent KH-570. The effect of mass fraction of nano-SiO2 particles and dosage of KH-570 on the toughening and strengthening of PP matrix were investigated based on the fractography of impact notch and the analysis of crystal structure by X-ray and dispersive structure of nano-SiO2 by TEM. Results show that the impact and flexural strength and modulus of the composite are improved obviously with low loading of nano-SiO2 (3wt%-5wt%), and the izod impact strength of PP increases twice with 4wt% nano-SiO2. The nano-SiO2 particles treated can disperse into the matrix resin, which has evident heterogeneous nucleation effects on the crystallization of PP. The optimal toughening and strengthening effects of PP matrix can be obtained when the content of nano-SiO2 and KH-570 are 4wt% and 3wt%, respectively.

  13. Control of the wetting properties of ^{4}He crystals in superfluid.

    Science.gov (United States)

    Takahashi, T; Minezaki, H; Suzuki, A; Obara, K; Itaka, K; Nomura, R; Okuda, Y

    2016-05-01

    To investigate whether it is possible to control the wetting of ^{4}He crystals on a wall in superfluid, the contact angles of ^{4}He crystals were measured on rough and smooth walls at very low temperatures. A rough wall was prepared in a simple manner in which a commercially available coating agent for car mirrors, which makes the glass surface superhydrophobic, was used to coat a glass plate. The contact angles of ^{4}He crystals were increased by approximately 10^{∘} on the rough wall coated with the agent. Therefore, the increase in the repellency of ^{4}He crystals in superfluid was demonstrated to be possible on a very rough surface. The enhancement of the contact angles and a scanning electron microscopy image of the coated surface both suggest that a Cassie-Baxter state of ^{4}He crystals was realized on the surface; the crystals did not have full contact with the wall, but entrapped superfluid was present beneath the crystals in the hollow parts of the rough wall.

  14. Structural, optical and photocatalytic properties of flower-like ZnO nanostructures prepared by a facile wet chemical method

    Directory of Open Access Journals (Sweden)

    Sini Kuriakose

    2013-11-01

    Full Text Available Flower-like ZnO nanostructures were synthesized by a facile wet chemical method. Structural, optical and photocatalytic properties of these nanostructures have been studied by X-ray diffraction (XRD, scanning electron microscopy (SEM, transmission electron microscopy (TEM, photoluminescence (PL and UV–vis absorption spectroscopy. SEM and TEM studies revealed flower-like structures consisting of nanosheets, formed due to oriented attachment of ZnO nanoparticles. Flower-like ZnO structures showed enhanced photocatalytic activity towards sun-light driven photodegradation of methylene blue dye (MB as compared to ZnO nanoparticles. XRD, UV–vis absorption, PL, FTIR and TEM studies revealed the formation of Zn(OH2 surface layer on ZnO nanostructures upon ageing. We demonstrate that the formation of a passivating Zn(OH2 surface layer on the ZnO nanostructures upon ageing deteriorates their efficiency to photocatalytically degrade of MB.

  15. Outstanding field emission properties of wet-processed titanium dioxide coated carbon nanotube based field emission devices

    Science.gov (United States)

    Xu, Jinzhuo; Xu, Peng; Ou-Yang, Wei; Chen, Xiaohong; Guo, Pingsheng; Li, Jun; Piao, Xianqing; Wang, Miao; Sun, Zhuo

    2015-02-01

    Field emission devices using a wet-processed composite cathode of carbon nanotube films coated with titanium dioxide exhibit outstanding field emission characteristics, including ultralow turn on field of 0.383 V μm-1 and threshold field of 0.657 V μm-1 corresponding with a very high field enhancement factor of 20 000, exceptional current stability, and excellent emission uniformity. The improved field emission properties are attributed to the enhanced edge effect simultaneously with the reduced screening effect, and the lowered work function of the composite cathode. In addition, the highly stable electron emission is found due to the presence of titanium dioxide nanoparticles on the carbon nanotubes, which prohibits the cathode from the influence of ions and free radical created in the emission process as well as residual oxygen gas in the device. The high-performance solution-processed composite cathode demonstrates great potential application in vacuum electronic devices.

  16. 水足迹与印染%Water footprint and textile wet processing

    Institute of Scientific and Technical Information of China (English)

    王东; 李戎; 宋阳; 王建庆; 阎克路

    2011-01-01

    水足迹计量是指某产品在整个供应链中用于生产该产品所需新鲜水的使用量.水足迹分析法能改善水资源的管理,为个人、企业或国家改善水资源的管理提供途径.纺织印染行业不仅是高耗水行业,也是高废水排放行业,水资源的利用率影响纺织印染行业的未来发展.文中介绍了水足迹分析法,阐述了纺织印染行业核算水足迹的意义.%The water footprint of a product is defined as the total volume of fresh water that is used directly or indirecly to produce the product. The water footprint analysis approach provides a means of improving water resources management for an individual, enterprise or state. The dyeing and finishing industry is not only the water intensive industry, but also a high wastewater discharge industry. To improve the utilization of water resources have great impact on the dyeing and finishing industry. The significance of water footprint accounting in dyeing and finishing industry is discussed by using the water footprint analysis approach.

  17. Gas Property Demonstrations Using Plastic Water Bottles

    Science.gov (United States)

    Campbell, Dean J.; Bannon, Stephen J.; Gunter, Molly M.

    2011-01-01

    Plastic water bottles are convenient containers for demonstrations of gas properties illustrating Boyle's law, Charles's law, and Avogadro's law. The contents of iron-based disposable hand warmer packets can be used to remove oxygen gas from the air within an unfilled plastic water bottle.

  18. Optical properties of a tropical estuary during wet and dry conditions in the Nha Phu estuary, Khanh Hoa Province, south-east Vietnam

    DEFF Research Database (Denmark)

    Lund-Hansen, Lars Chresten; Hai, Doan Nhu; Lam, Nguyen Ngoc

    2010-01-01

    There has been a strong research focus on optical properties in temperate estuaries but very much less in tropical estuaries. These properties comprise light and beam attenuation dominated by suspended particulate matter, Chl a, and CDOM. Spatially and temporally distributed data on optical prope...... estuaries, was the episodic character with days of strong rainfall followed by longer periods of dry weather. All sampling, both wet and dry, was carried out in the dry season which implies a less definitive perception of wet and dry seasons....

  19. Degradation of Pore Structure and Microstructures in Hardened Cement Paste Subjected to Flexural Loading and Wet-dry Cycles in Sea Water

    Institute of Scientific and Technical Information of China (English)

    ZHANG Wuman; SUN Wei; ZHANG Yunsheng; CHEN Huisu

    2009-01-01

    Hardened cement paste was subjected to the flexural loading and wet-dry cycles in sea water.The degradation of microstructures was obtained using scanning electron microscope(SEM),and the energy dispersive spectrum(EDS)analysis was carried to analyze the local composition.Mercury intrusion porosimetry(Poremaster GT-60)was used to analyze the degradation of pore structures.The experimental results show that the synergistic action of the flexural loading,wet-dry cycles and sea water leads to significant deterioration of hardened cement paste.The degradation of microstructures in the tensile region is more serious than that in the compressive region.The flexural loading and wet-dry cycles accelerate the chemical attack of sea water.

  20. Dry and wet heat transfer through clothing dependent on the clothing properties under cold conditions

    NARCIS (Netherlands)

    Richards, M.G.M.; Rossi, R.; Meinander, H.; Broede, P.; Candas, V.; Hartog, E.A. den; Holmér, I.; Nocker, W.; Havenith, G.

    2008-01-01

    The purpose of this study was to investigate the effect of moisture on the heat transfer through clothing in relation to the water vapour resistance, type of underwear, location of the moisture and climate. This forms part of the work performed for work package 2 of the European Union THERMPROTECT p

  1. Production of BSA-poly(ethyl cyanoacrylate) nanoparticles as a coating material that improves wetting property

    Science.gov (United States)

    Alkyl cyanoacrylates have long been used for the synthesis of colloidal nanoparticles. In the involved polymerization reaction, OH- ions derived from dissociation of water have been used as an initiator. In the current research, an animal protein, bovine serum albumin (BSA) molecules were utilized a...

  2. Understanding Microstructural Properties of Perovskite Ceramics through Their Wet-Chemical Synthesis

    NARCIS (Netherlands)

    Stawski, Tomasz

    2011-01-01

    This thesis comprises of seven full research chapters on the morphology, properties and processing of sol-gel precursor systems of barium titanate and lead zirconate titanate thin films and powders. In all the considered problems, the synthesis leading to nano-sized perovskite ceramics constitutes

  3. Water and Ethanol Droplet Wetting Transition during Evaporation on Omniphobic Surfaces

    OpenAIRE

    Xuemei Chen; Weibel, Justin A.; Garimella, Suresh V.

    2015-01-01

    Omniphobic surfaces with reentrant microstructures have been investigated for a range of applications, but the evaporation of high- and low-surface-tension liquid droplets placed on such surfaces has not been rigorously studied. In this work, we develop a technique to fabricate omniphobic surfaces on copper substrates to allow for a systematic examination of the effects of surface topography on the evaporation dynamics of water and ethanol droplets. Compared to a water droplet, the ethanol dr...

  4. Analysis on the daily courses of water potential of nine woody species from Cerrado vegetation during wet season

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The water potential (Y ) daily courses of 9 woody species from Cerrado vegetation in different weather conditions during wet season were observed and analyzed. The adjusting strategies of 9 species could be divided into 3 groups according to Cluster Analysis and based on the data observed on the January 18, March 20 and April 6. The Y values of the first group, which included 2 species, were maintained at the higher level consistently. The Y values of the second group, which included 5 species, were intermediate level. The Y values of the third group, which included 2 species, were kept in the lower level. The Y values of all species always kept pace with the weather condition, especially water condition. During the clear day only one Y value peak for all species occurred at midday (12:30-13:30). When the overcast or raining occurred for a short period, the fluctuation of Y values would appear after about 15-30 min responding to the change of weather condition. Even in the same group under the same external circumstance, there was a clear variation of the leaf Y values among different species, which showed that the strategy diversity for plant to balance water relation. From January to April, the Y values of 9 species reduced in response to the drought condition. The species with the lower values of water saturation deficiency at turgid loss point (Wsdtlp), the osmotic potential at saturation (p sat), the osmotic potential at turgid lose point (p tlp) or lower predawn water potential (Y pd) usually had the lower Y values at midday. The mechanism of water balance controlled by many systems has been assumed.

  5. Moderate wetting and drying increases rice yield and reduces water use, grain arsenic level, and methane emission

    Directory of Open Access Journals (Sweden)

    Jianchang Yang

    2017-04-01

    Full Text Available To meet the major challenge of increasing rice production to feed a growing population under increasing water scarcity, many water-saving regimes have been introduced in irrigated rice, such as an aerobic rice system, non-flooded mulching cultivation, and alternate wetting and drying (AWD. These regimes could substantially enhance water use efficiency (WUE by reducing irrigation water. However, such enhancements greatly compromise grain yield. Recent work has shown that moderate AWD, in which photosynthesis is not severely inhibited and plants can rehydrate overnight during the soil drying period, or plants are rewatered at a soil water potential of −10 to −15 kPa, or midday leaf potential is approximately −0.60 to −0.80 MPa, or the water table is maintained at 10 to 15 cm below the soil surface, could increase not only WUE but also grain yield. Increases in grain yield WUE under moderate AWD are due mainly to reduced redundant vegetative growth; improved canopy structure and root growth; elevated hormonal levels, in particular increases in abscisic acid levels during soil drying and cytokinin levels during rewatering; and enhanced carbon remobilization from vegetative tissues to grain. Moderate AWD could also improve rice quality, including reductions in grain arsenic accumulation, and reduce methane emissions from paddies. Adoption of moderate AWD with an appropriate nitrogen application rate may exert a synergistic effect on grain yield and result in higher WUE and nitrogen use efficiency. Further research is needed to understand root–soil interaction and evaluate the long-term effects of moderate AWD on sustainable agriculture.

  6. Consolidating and water repellent treatments applied to wet and salt contaminated granite

    Directory of Open Access Journals (Sweden)

    Silva, B.

    2000-03-01

    Full Text Available A comparison was made of the efficacy of two consolidants and two water repellents applied to samples of granite under optimum conditions, with the efficacy of the same products applied to the granite in the presence of soluble salts or water. The amount of product absorbed and the amount of dry polymer remaining after treatment were compared. The results show that the presence of water and soluble salts in the stone significantly modifies the consumption of the products (in particular the water repellents and also the level of dry polymer retained. The water repellents were found to be much less effective when the substrate contained salts, whereas the presence of water did not appear to influence their efficacy. The lack of correlation between uptake, active dry polymer, and efficacy led to the conclusion that the presence of salts or water markedly changes the kinetics of the polymerization of the products.

    Se analiza la eficacia de dos consolidantes y dos hidrofugantes aplicados a rocas graníticas en condiciones óptimas comparativamente a la eficacia de los mismos productos aplicados sobre los mismos sustratos conteniendo cierta cantidad de sales solubles o de agua. Se compara la cantidad de producto absorbido y la cantidad de materia seca presente tras el curado. Los resultados indican que la presencia de agua y de sales solubles en la piedra modifica significativamente el consumo de los productos, sobre todo el de los hidrofugantes, así como la cantidad de materia seca. Se observa, asimismo, un fuerte detrimento en la eficacia de los hidrofugantes cuando el sustrato contiene sales mientras que, al contrario, la presencia de agua no parece infiuir en dicha eficacia. La falta de correlación entre el consumo, materia seca activa y eficacia lleva a concluir que la presencia de sales o agua modifica sensiblemente la cinética de la polimeración de los productos.

  7. Application of advanced oxidation processes for cleaning of industrial water generated in wet dedusting of shaft furnace gases.

    Science.gov (United States)

    Czaplicka, Marianna; Kurowski, Ryszard; Jaworek, Katarzyna; Bratek, Łukasz

    2013-01-01

    The paper presents results of studies into advanced oxidation processes in 03 and 03/UV systems. An advanced oxidation process (AOP) was conducted to reduce the load of impurities in circulating waters from wet de-dusting of shaft furnace gases. Besides inorganic impurities, i.e. mainly arsenic compounds (16 g As L(-1) on average), lead, zinc, chlorides and sulphates, the waters also contain some organic material. The organic material is composed of a complex mixture that contains, amongst others, aliphatic compounds, phenol and its derivatives, pyridine bases, including pyridine, and its derivatives. The test results show degradation of organic and inorganic compounds during ozonation and photo-oxidation processes. Analysis of the solutions from the processes demonstrated that the complex organic material in the industrial water was oxidized in ozonation and in photo-oxidation, which resulted in formation of aldehydes and carboxylic acids. Kinetic degradation of selected pollutants is presented. Obtained results indicated that the O3/UV process is more effective in degradation of organic matter than ozonation. Depending on the process type, precipitation of the solid phase was observed. The efficiency of solid-phase formation was higher in photo-oxidation with ozone. It was found that the precipitated solid phase is composed mainly of arsenic, iron and oxygen.

  8. WetNet: Using SSM/I data interactively for global distribution of rainfall and precipitable water

    Science.gov (United States)

    Zipser, Edward J.; Mcguirk, James P.

    1991-01-01

    By completing hardware installation, preparing for comparative studies of SSM/I, radar, and lightning data, it is believed that this will be a powerful combination for evaluating the global distribution of tropical rainfall, and the vertical distribution of latent heating, with strong application to algorithms for use on TRMM, EOS-A, and future GOES spacecraft. Potential data bases will be surveyed, about 5 case studies with surface rainfall, radar, lightning, and sounding data will be identified. SSM/I algorithms will be used to identify convective regions of MCSs. A catalog will be developed of the global profile of heavy tropical rainfall, and how these zones are organized within larger tropical weather systems. Beginning with the first few months of SSM/I data distributed over WetNet, SSM/I radiances will be compared with TOVS radiance (moisture and thermal) and OLR observations. The purpose is to improve understanding of how real world water vapor profiles in the tropical atmosphere are perceived by SSM/I precipitable water algorithm and, at the same time, by the TOVS water vapor channel.

  9. Physico-mechanical and physico-chemical properties of synthesized cement based on plasma- and wet technologies

    Science.gov (United States)

    Sazonova, Natalya; Skripnikova, Nelli

    2016-01-01

    In this work we studied the influence of plasma-chemical technology of cement clinker synthesis under conditions of high-concentrated heat streams on the properties of cement on fixing such factors as raw-material type (chemical and mineralogical composition), fraction composition, homogenization and module characters of the raw-material mixture. In this connection the sludge of the cement plant in town Angarsk, based on which the cement clinker synthesis using the wet- and plasma-chemical technologies was performed, was used in the studies. The results of chemical X-ray-phase analysis, petrography of cement clinkers, differential scanning colorimetry of hardened cement paste are represented in this work. The analysis of building-technical properties of inorganic viscous substances was performed. It was found that in using the identical raw-material mixture the cement produced with temperature higher by 1650 °C than the traditional one may indicate the higher activity. The hardened cement paste compressive strength at the age of 28 days was higher than the strength of the reference samples by 40.8-41.4 %.

  10. Evaporation-Triggered Wetting Transition for Water Droplets upon Hydrophobic Microstructures

    NARCIS (Netherlands)

    Tsai, Peichun; Lammertink, Rob G.H.; Wessling, Matthias; Lohse, Detlef

    2010-01-01

    When placed on rough hydrophobic surfaces, water droplets of diameter larger than a few millimeters can easily form pearls, as they are in the Cassie-Baxter state with air pockets trapped underneath the droplet. Intriguingly, a natural evaporating process can drive such a Fakir drop into a completel

  11. Ion adsorption-induced wetting transition in oil-water-mineral systems

    NARCIS (Netherlands)

    Bera, B.; Sîretanu, Igor; Maestro, Armando; Duits, Michael H.G.; Cohen Stuart, Martinus Abraham; van den Ende, Henricus T.M.; Mugele, Friedrich Gunther; Collins, I

    2015-01-01

    The relative wettability of oil and water on solid surfaces is generally governed by a complex competition of molecular interaction forces acting in such three-phase systems. Herein, we experimentally demonstrate how the adsorption of in nature abundant divalent Ca2+ cations to solid-liquid interfac

  12. Ion adsorption-induced wetting transition in oil-water-mineralsystems

    NARCIS (Netherlands)

    Mugele, Friedrich Gunther; Bera, B.; Cavalli, Andrea; Sîretanu, Igor; Maestro, Armando; Duits, Michael H.G.; Cohen Stuart, Martinus Abraham; van den Ende, Henricus T.M.; Stocker, I.; Collins, I

    2015-01-01

    The relative wettability of oil and water on solid surfaces is generally governed by a complex competition of molecular interaction forces acting in such three-phase systems. Herein, we experimentally demonstrate how the adsorption of in nature abundant divalent Ca2+ cations to solid-liquid interfac

  13. The role of wetting on the water flux performance of microsieve membranes

    NARCIS (Netherlands)

    Girones nogue, Miriam; Borneman, Zandrie; Lammertink, Rob G.H.; Wessling, Matthias

    2005-01-01

    Microsieve membranes are microfabricated devices that possess a high and controlled porosity. Due to the extremely high product throughput, microsieves are very sensitive systems in terms of flux decline during clean water measurements. The goal of this investigation was to study the influence of

  14. Impact of long term wetting on pore water chemistry in a peat bog in Ontario, Canada

    Science.gov (United States)

    Schaper, Jonas; Blodau, Christian; Holger Knorr, Klaus

    2013-04-01

    Peatlands of the northern hemisphere store a remarkable amount of carbon but also contribute to global methane emissions. As large areas in the boreal and subarctic zone are considered to undergo significant climate change it is necessary to understand how these ecosystems react to altered environmental conditions. Since not only temperatures but also precipitation is likely to increase in these regions, it is of particular interest to understand the impact of raised water tables and changing local hydrological flow patterns on peatlands' carbon cycle. We chose a pristine bog that was partly flooded by a reservoir lake created 60 years ago in Ontario, Canada. Water management in the reservoir resulted in seasonal flooding, shifting hydrological flow patterns and vegetation gradients. The impact of partial flooding on pore water chemistry and DIC and CH4 concentrations were studied within surface peat layers. Samples were taken with pore water peepers along the vegetation- and flooding gradient. Turnover rates of DIC and methane were calculated from obtained concentration profiles and peat porosity under the assumption that transport is dominated by diffusion. Values of pH changed remarkably from 4 within the undisturbed bog part to almost 8 at the lake shore. Ca2+ and Mg2+ were the only ions that showed significant distribution patterns with readily increasing concentrations towards the lake water body. CH4 and DIC concentrations also increased towards the lake and peaked in around 100 cm depth right at the shore with maximum concentrations being 2766 μmol L-1 for CH4 and 7543 μmol L-1 for DIC, respectively. Turnover rates also increased towards the shore albeit some uncertainty lies in this finding as steady state condition required for calculations were probably not established and transport was not only dominated by diffusion. Maximum CH4 production rates were modeled to be 36 nmol cm-3 d-1 and maximum DIC production was calculated to 64 nmol cm-3 d-1. Ca2

  15. Experimental Investigation of Effects of Vibration upon Elastic and Cohesive Properties of Beds of Wet Sand

    Directory of Open Access Journals (Sweden)

    S. Alsop

    1995-01-01

    Full Text Available The transmission of sinusoidal vibrations through beds of cohesive particulate solids was measured. Results were interpreted in terms of a critical state model to predict the elastic swelling constant k, and the cohesive stress C. Factorial experimental design was used to identify significant parameters. Factors that affect k include percent moisture, bulk density, sample size, sample shape, the presence of a supporting membrane, and loading order. Factors that affect C include percent moisture and particle size distribution. Factors affecting k were interpreted in terms of their effects upon bed structure and factors affecting C in terms of an equivalent pore water pressure due to capillary and liquid bridge effects. The critical state model was modified to incorporate general relationships between axial and radial strains.

  16. Mobile Information Collection Application: Water Equipment Tracker (MICA:WET) Tool

    Science.gov (United States)

    2013-10-01

    Processor Unit TEMF Tactical Equipment Maintenance Facility TR Technical Report TWDB Texas Water Development Board UPH Unaccompanied Personnel...1731 Trans Unaccompanied Personnel Housing ( UPH ) Advanced Individual Training (AIT) 4109 Consol Open Din (metered) 1789 AIT Barrack 10:30-12:00...1732 Trans UPH AIT 5268 Car Wash 470 Admin Gen Purpose Lunch Break 1:30-3:30 1784 DFAC 11480 Tech Eq Maintenance Facility 1607 Museum 2:30-3:30

  17. Exploring Localized Mixing Dynamics during Wet Weather in a Tidal Fresh Water System

    Directory of Open Access Journals (Sweden)

    Ramona Stammermann

    2014-04-01

    Full Text Available A recently validated 3-dimensional implementation of the Environmental Fluid Dynamic Code (EFDC for the tidal-fresh portions of the Delaware Estuary was exercised against the results of a dye release from a sewer outfall during a storm. The influence on dye distribution in the estuary resulting from variations in wind and local storm water discharges in an urban area is investigated. The modeled domain stretches 116 km from the head of tide and includes hydrologic input from 33 streams and a number of municipal and industrial discharges. Bottom roughness was parameterized from sedimentological and geophysical surveys. Model validation to-date relies upon field observations and tidal harmonics for sea level and currents derived from the NOAA-NOS 1984–1985 circulation survey and a current survey conducted by the Philadelphia Water Department (PWD. Model representation of dye distribution compared favorably for observations of concentrations in the dye plume from 10 cross-sections spanning the extent of the plume over seven tidal cycles. The dye distribution was characterized by an initial period of high local storm water and stream inflows with low wind conditions, lasting for several tidal cycles, followed by a period of reduced fresh water input and increasing wind stress. The dye experiment provided a unique opportunity to observe the performance of the model through the transition between these two very different meteorological periods, and to explore the physical conditions driving the hydrodynamics through both observations and numerical experiments. The influences of local meteorological forcing and channel morphology on lateral mixing, dispersion and longitudinal dynamics are characterized.

  18. Aqueous Wetting Films on Fused Quartz.

    Science.gov (United States)

    Mazzoco; Wayner

    1999-06-15

    Using an image analyzing interferometer, IAI, the interfacial characteristics of an isothermal constrained vapor bubble, CVB, in a quartz cuvette were studied as a precursor to heat transfer research. The effects of pH and electrolyte concentration on the meniscus properties (curvature and adsorbed film thickness) and the stability of the aqueous wetting films were evaluated. The surface potential in the electric double layer was a function of the cleaning and hydroxylation of the quartz surface. The disjoining pressure isotherm for pure water was very close to that predicted by the Langmuir equation. For aqueous solutions of moderate electrolyte concentration, the Gouy-Chapman theory provided a good representation of the electrostatic effects in the film. The effect of temperature on the film properties of aqueous solutions and pure water was also evaluated: The meniscus curvature decreased with increasing temperature, while Marangoni effects, intermolecular forces, and local evaporation and condensation enhanced waves on the adsorbed film layer. Pure water wetting films were mechanically metastable, breaking into droplets and very thin films (less than 10 nm) after a few hours. Aqueous wetting films with pH 12.4 proved to be stable during a test of several months, even when subjected to temperature and mechanical perturbations. The mechanical stability of wetting films can explain the reported differences between the critical heat fluxes of pure water and aqueous solutions. The IAI-CVB technique is a simple and versatile experimental technique for studying the characteristics of interfacial systems. Copyright 1999 Academic Press.

  19. Droplet impact upon a wet surface with varied fluid and surface properties.

    Science.gov (United States)

    Pan, Kuo-Long; Hung, Chun-Yu

    2010-12-01

    The transition boundaries of various regimes characterizing the impact outcomes of a droplet upon a liquid layer of small thickness were investigated experimentally. With careful control of film thickness, the onset of these regimes in terms of a Weber number (We), which expresses the ratio between the droplet inertia and surface force, specifically when the layer depth is smaller than the droplet diameter, has been further clarified, as compared to prior studies. Several turning, non-monotonic trends between We and the film thickness normalized by the droplet diameter, H, were thus identified as H≲1. Furthermore, by adding various percentages of glycerine, the effects of liquid viscosity were revealed, which inhibited disintegration into secondary droplets. We also added surfactant to change the surface tension, leading to further complication of the collision outcome that would be related to the interaction between the crater and the bottom surface. The material effect of the solid surface was hence studied for further demonstration of such interplays. The results showed that increasing viscosity would essentially delay the occurrence of these transitions whereas reducing surface tension might encourage the onset. Therefore a possibility of using additives to manipulate the collision outcomes, while not changing much the constituent fluid properties, is presented. Copyright © 2010 Elsevier Inc. All rights reserved.

  20. Wrinkling of wet paper

    Science.gov (United States)

    Kim, Ho-Young; Kim, Jungchul; Mahadevan, L.

    2011-11-01

    It is a mundane experience that paper stained with water wrinkles. It is because a wetted portion of paper, which swells due to the hygroexpansive nature of the cellulose fiber network, deforms out of its original plane. Here we quantify the dynamics of wrinkling of wet paper coupled to the capillary imbibition of water into paper using a combination of experiment and theory. While supplying water from a capillary tube that touches the center of a paper strip, we measure the spreading rate of the wet area, wait time for the out-of-plane buckling, and temporal growth of a wrinkling magnitude. Using a theoretical model assuming a linear increase of the strain and an exponential decay of the elastic modulus with the water concentration, we construct scaling laws to predict the simultaneous capillary imbibition and wrinkling rates. This work was supported by the Wyss Institute of Harvard University.

  1. Overview of economic, legal, and water availability factors affecting the demand for dry and wet/dry cooling for thermal power plants

    Energy Technology Data Exchange (ETDEWEB)

    Hendrickson, P.L.

    1977-06-01

    The economic, legal, and water availability factors which will contribute to selection in the future, of dry and wet/dry cooling vis-a-vis other methods of cooling and which will influence the projected market for these types of cooling systems in the next twenty years are considered.

  2. Outstanding field emission properties of wet-processed titanium dioxide coated carbon nanotube based field emission devices

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jinzhuo; Ou-Yang, Wei, E-mail: ouyangwei@phy.ecnu.edu.cn; Chen, Xiaohong; Guo, Pingsheng; Piao, Xianqing; Sun, Zhuo [Engineering Research Center for Nanophotonics and Advanced Instrument, Ministry of Education, Department of Physics, East China Normal University, 3663 North Zhongshan Road, Shanghai 200062 (China); Xu, Peng; Wang, Miao [Department of Physics, Zhejiang University, 38 ZheDa Road, Hangzhou 310027 (China); Li, Jun [Department of Electronic Science and Technology, Tongji University, 4800 Caoan Road, Shanghai 201804 (China)

    2015-02-16

    Field emission devices using a wet-processed composite cathode of carbon nanotube films coated with titanium dioxide exhibit outstanding field emission characteristics, including ultralow turn on field of 0.383 V μm{sup −1} and threshold field of 0.657 V μm{sup −1} corresponding with a very high field enhancement factor of 20 000, exceptional current stability, and excellent emission uniformity. The improved field emission properties are attributed to the enhanced edge effect simultaneously with the reduced screening effect, and the lowered work function of the composite cathode. In addition, the highly stable electron emission is found due to the presence of titanium dioxide nanoparticles on the carbon nanotubes, which prohibits the cathode from the influence of ions and free radical created in the emission process as well as residual oxygen gas in the device. The high-performance solution-processed composite cathode demonstrates great potential application in vacuum electronic devices.

  3. Carbon isotope analysis of dissolved organic carbon in fresh and saline (NaCl) water via continuous flow cavity ring-down spectroscopy following wet chemical oxidation.

    Science.gov (United States)

    Conaway, Christopher H; Thomas, Burt; Saad, Nabil; Thordsen, James J; Kharaka, Yousif K

    2015-01-01

    This work examines the performance and limitations of a wet chemical oxidation carbon analyser interfaced with a cavity ring-down spectrometer (WCO-CRDS) in a continuous flow (CF) configuration for measuring δ(13)C of dissolved organic carbon (δ(13)C-DOC) in natural water samples. Low-chloride matrix (oxidation despite using high-concentration oxidant, extended reaction time, or post-wet chemical oxidation gas-phase combustion. However, through a combination of dilution, chloride removal, and increasing the oxidant:sample ratio, high-salinity samples with sufficient DOC (>22.5 µg C/aliquot) may be analysed. The WCO-CRDS approach requires more total carbon (µg C/aliquot) than conventional CF-isotope ratio mass spectrometer, but is nonetheless applicable to a wide range of DOC concentration and water types, including brackish water, produced water, and basinal brines.

  4. Effect of diaper cream and wet wipes on skin barrier properties in infants: a prospective randomized controlled trial.

    Science.gov (United States)

    Garcia Bartels, Natalie; Lünnemann, Lena; Stroux, Andrea; Kottner, Jan; Serrano, José; Blume-Peytavi, Ulrike

    2014-01-01

    The effect of different diaper care procedures on skin barrier function in infants has been minimally investigated and may be assessed using objective methods. In a single-center, prospective trial, 89 healthy 9-month-old infants (±8 wks) were randomly assigned to three diaper care regimens: group I used water-moistened washcloths at diaper changes (n = 30), group II additionally applied diaper cream twice daily (n = 28), and group III used wet wipes and diaper cream twice daily (n = 31). Transepidermal water loss (TEWL), skin hydration (SCH), skin pH, interleukin 1α (IL-1α) levels, and microbiologic colonization were measured in diapered skin (upper outer quadrant of the buttocks), nondiapered skin (upper leg), and if diaper dermatitis (DD) occurred, using the most affected skin area at day 1 and weeks 4 and 8. Skin condition was assessed utilizing a neonatal skin condition score and diaper rash grade. On diapered skin, SCH decreased in groups II and III, whereas TEWL values were reduced in group II only. Skin pH increased in groups II and III. In general, SCH, skin pH, and IL-1α levels were higher in healthy diapered skin than in nondiapered skin. The incidence and course of DD was comparable in all groups. Areas with DD had greater TEWL and skin pH than unaffected skin areas. Infants who received diaper cream had lower SCH and TEWL and higher pH levels in the diapered area than on nondiapered skin. No correlation with the occurrence of DD was found. © 2014 Wiley Periodicals, Inc.

  5. Optical properties of water for the Yangbajing water cherenkov detector

    Science.gov (United States)

    Gao, Shang-qi; Sun, Zhi-bin; Jiang, Yuan-da; Wang, Chao; Du, Ke-ming

    2011-08-01

    Cherenkov radiation is used to study the production of particles during collisions, cosmic rays detections and distinguishing between different types of neutrinos and electrons. The optical properties of water are very important to the research of Cherenkov Effect. Lambert-beer law is a method to study the attenuation of light through medium. In this paper, optical properties of water are investigated by use of a water attenuation performance test system. The system is composed of the light-emitting diode (LED) light source and the photon receiver models. The LED light source model provides a pulse light signal which frequency is 1 kHz and width is 100ns. In photon receiver model, a high sensitivity photomultiplier tube (PMT) is used to detect the photons across the water. Because the output voltage amplitude of PMT is weak which is from 80mv to 120mV, a low noise pre-amplifier is used to improve the detector precise. An effective detector maximum time window of PMT is 100ns for a long lifetime, so a peak holder circuit is used to hold the maximum peak amplitude of PMT for the induced photons signal before the digitalization. In order to reduce the noise of peak holder, a multi-pulse integration is used before the sampling of analog to digital converter. At last, the detector of photons from the light source to the PMT across the water is synchronized to the pulse width of the LED. In order to calculate the attenuation coefficient and attenuation length of water precisely, the attenuation properties of air-to-water boundary is considered in the calculation.

  6. Effects of Vermicompost and Water Treatment Residuals on Soil Physical Properties and Wheat Yield

    Science.gov (United States)

    Ibrahim, Mahmoud M.; Mahmoud, Essawy K.; Ibrahim, Doaa A.

    2015-04-01

    The application of vermicompost and water treatment residuals to improve the physical properties in the salt affected soils is a promising technology to meet the requirements of high plant growth and cost-effective reclamation. Therefore, the aim of this study was to investigate the effect of vermicompost and its mixtures with water treatment residuals on selected physical properties of saline sodic soil and on wheat yield. The treatments were vermicompost, water treatment residuals, vermicompost + water treatment residuals (1:1 and 2:1 wet weight ratio) at levels of 5 and 10 g dry weight kg-1 dry soil. The considered physical properties included aggregate stability, mean weight diameter, pore size distribution and dry bulk density. The addition of vermicompost and water treatment residuals had significant positive effects on the studied soil physical properties, and improved the grain yield of wheat. The treatment of (2 vermicompost + 1 water treatment residuals) at level of 5 g kg-1 soil gave the best grain yield. Combination of vermicompost and water treatment residuals improved the water treatment residuals efficiency in ameliorating the soil physical properties, and could be considered as an ameliorating material for the reclamation of salt affected soils.

  7. Thresholds in soil response to water stress: intensity and duration of dry-wet cycles induce differential soil C and bacterial diversity dynamics

    Science.gov (United States)

    Kaisermann, Aurore; Nunan, Naoise; Maron, Pierre-Alain; Terrat, Sébastien; Lata, Jean-Christophe

    2013-04-01

    After the wetting of dry soils, a CO2 flush (known as the 'Birch effect') is often observed. Although the Birch effect can often result in large CO2 fluxes, the process is not sufficiently well understood to predict its intensity. In particular, the impact of dry-wet cycles on microbial communities is poorly understood, as are the consequences of the possible changes for soil functioning. Using microcosm-based experiments, we investigated different climate change scenarios, such as drying periods of different durations (with co-variation of drying intensity and drought duration) and different rainfall intensities. The effects of four dry-wet cycles on the (i) immediate intensity of the Birch effect, (ii) rate of return to basal C mineralisation (functional resilience), (iii) total amount of CO2 released during a 5-month incubation and (iv) the dynamics of bacterial diversity were determined. Bacterial diversity was measured by pyrosequencing. The CO2 flush increased as a function of drying intensity, drought duration and wetting intensity but was not affected by the number of dry-wet cycles. However, the functional resilience was slower after the first dry-wet cycle than subsequent cycles, suggesting an adaptation of the microbial communities to water-stress. However, this was not associated with a higher stability of bacterial community since the pyrosequencing data showed that drying decreased bacterial diversity after each dry-wet cycle, but only if a threshold of minimal moisture is exceeded. These modifications were permanent over the long term and suggest that the communities were characterised by functional redundancy. Moderate droughts had no effect on overall CO2 emissions but severe droughts led to a lower loss of soil C due to the absence of mineralisation during the longer periods of desiccation that was not compensated by over-mineralisation during Birch effect. The study highlighted moisture threshold beyond which it can be observed a Birch effect and

  8. Wet storage integrity update

    Energy Technology Data Exchange (ETDEWEB)

    Bailey, W.J.; Johnson, A.B. Jr.

    1983-09-01

    This report includes information from various studies performed under the Wet Storage Task of the Spent Fuel Integrity Project of the Commercial Spent Fuel Management (CSFM) Program at Pacific Northwest Laboratory. An overview of recent developments in the technology of wet storage of spent water reactor fuel is presented. Licensee Event Reports pertaining to spent fuel pools and the associated performance of spent fuel and storage components during wet storage are discussed. The current status of fuel that was examined under the CSFM Program is described. Assessments of the effect of boric acid in spent fuel pool water on the corrosion and stress corrosion cracking of stainless steel and the stress corrosion cracking of stainless steel piping containing stagnant water at spent fuel pools are discussed. A list of pertinent publications is included. 84 references, 21 figures, 11 tables.

  9. Application of sludge-based carbonaceous materials in a hybrid water treatment process based on adsorption and catalytic wet air oxidation.

    Science.gov (United States)

    Julcour Lebigue, Carine; Andriantsiferana, Caroline; N'Guessan Krou; Ayral, Catherine; Mohamed, Elham; Wilhelm, Anne-Marie; Delmas, Henri; Le Coq, Laurence; Gerente, Claire; Smith, Karl M; Pullket, Suangusa; Fowler, Geoffrey D; Graham, Nigel J D

    2010-12-01

    This paper describes a preliminary evaluation of the performance of carbonaceous materials prepared from sewage sludges (SBCMs) in a hybrid water treatment process based on adsorption and catalytic wet air oxidation; phenol was used as the model pollutant. Three different sewage sludges were treated by either carbonisation or steam activation, and the physico-chemical properties of the resultant carbonaceous materials (e.g. hardness, BET surface area, ash and elemental content, surface chemistry) were evaluated and compared with a commercial reference activated carbon (PICA F22). The adsorption capacity for phenol of the SBCMs was greater than suggested by their BET surface area, but less than F22; a steam activated, dewatered raw sludge (SA_DRAW) had the greatest adsorption capacity of the SBCMs in the investigated range of concentrations (oxidation tests, the SBCMs demonstrated catalytic behaviour arising from their substrate adsorptivity and metal content. Recycling of SA_DRAW in successive oxidations led to significant structural attrition and a hardened SA_DRAW was evaluated, but found to be unsatisfactory during the oxidation step. In a combined adsorption-oxidation sequence, both the PICA carbon and a selected SBCM showed deterioration in phenol adsorption after oxidative regeneration, but a steady state performance was reached after 2 or 3 cycles.

  10. Wide-Band Airborne Microwave and Millimeter-Wave Radiometers to Provide High-Resolution Wet-Tropospheric Path Delay Corrections for Coastal and Inland Water Altimetry

    Science.gov (United States)

    Reising, Steven C.; Kangaslahti, Pekka; Brown, Shannon T.; Tanner, Alan B.; Padmanabhan, Sharmila; Parashare, Chaitali; Montes, Oliver; Dawson, Douglas E.; Gaier, Todd C.; Khayatian, Behrouz; Bosch-Lluis, Xavier; Nelson, Scott P.; Johnson, Thaddeus; Hadel, Victoria; Gilliam, Kyle L.; Razavi, Behzad

    2013-04-01

    Current satellite ocean altimeters include nadir-viewing, co-located 18-34 GHz microwave radiometers to measure wet-tropospheric path delay. Due to the area of the surface instantaneous fields of view (IFOV) at these frequencies, the accuracy of wet path retrievals is substantially degraded near coastlines, and retrievals are not provided over land. Retrievals are flagged as not useful about 40 km from the world's coastlines. A viable approach to improve their capability is to add wide-band millimeter-wave window channels at 90 to 170 GHz, yielding finer spatial resolution for a fixed antenna size. In addition, NASA's Surface Water and Ocean Topography (SWOT) mission in formulation (Phase A) is planned for launch in late 2020. The primary objectives of SWOT are to characterize ocean sub-mesoscale processes on 10-km and larger scales in the global oceans, and to measure the global water storage in inland surface water bodies and the flow rate of rivers. Therefore, an important new science objective of SWOT is to transition satellite radar altimetry into the coastal zone. The addition of millimeter-wave channels near 90, 130 and 166 GHz to current Jason-class radiometers is expected to improve retrievals of wet-tropospheric delay in coastal areas and to enhance the potential for over-land retrievals. The Ocean Surface Topography Science Team Meeting recommended in 2012 to add these millimeter-wave channels to the Jason Continuity of Service (CS) mission. To reduce the risks associated with wet-tropospheric path delay correction over coastal areas and fresh water bodies, we are developing an airborne radiometer with 18.7, 23.8 and 34.0 GHz microwave channels, as well as millimeter-wave window channels at 90, 130 and 166 GHz, and temperature sounding above 118 as well as water vapor sounding below 183 GHz for validation of wet-path delay. For nadir-viewing space-borne radiometers with no moving parts, two-point internal calibration sources are necessary, and the

  11. Occurrence of Blastocystis sp. in water catchments at Malay villages and Aboriginal settlement during wet and dry seasons in Peninsular Malaysia

    Directory of Open Access Journals (Sweden)

    Samseh Abdullah Noradilah

    2016-10-01

    Full Text Available In the tropics, there are too few studies on isolation of Blastocystis sp. subtypes from water sources; in addition, there is also an absence of reported studies on the occurrence of Blastocystis sp. subtypes in water during different seasons. Therefore, this study was aimed to determine the occurrence of Blastocystis sp. subtypes in river water and other water sources that drained aboriginal vicinity of highly endemic intestinal parasitic infections during wet and dry seasons. Water samples were collected from six sampling points of Sungai Krau (K1–K6 and a point at Sungai Lompat (K7 and other water sources around the aboriginal villages. The water samples were collected during both seasons, wet and dry seasons. Filtration of the water samples were carried out using a flatbed membrane filtration system. The extracted DNA from concentrated water sediment was subjected to single round polymerase chain reaction and positive PCR products were subjected to sequencing. All samples were also subjected to filtration and cultured on membrane lactose glucuronide agar for the detection of faecal coliforms. During wet season, Blastocystis sp. ST1, ST2 and ST3 were detected in river water samples. Blastocystis sp. ST3 occurrence was sustained in the river water samples during dry season. However Blastocystis sp. ST1 and ST2 were absent during dry season. Water samples collected from various water sources showed contaminations of Blastocystis sp. ST1, ST2, ST3 and ST4, during wet season and Blastocystis sp. ST1, ST3, ST8 and ST10 during dry season. Water collected from all river sampling points during both seasons showed growth of Escherichia coli and Enterobacter aerogenes, indicating faecal contamination. In this study, Blastocystis sp. ST3 is suggested as the most robust and resistant subtype able to survive in any adverse environmental condition. Restriction and control of human and animal faecal contaminations to the river and other water sources

  12. Occurrence of Blastocystis sp. in water catchments at Malay villages and Aboriginal settlement during wet and dry seasons in Peninsular Malaysia

    Science.gov (United States)

    Noradilah, Samseh Abdullah; Lee, Ii Li; Anuar, Tengku Shahrul; Salleh, Fatmah Md; Abdul Manap, Siti Nor Azreen; Mohd Mohtar, Noor Shazleen Husnie; Azrul, Syed Muhamad; Abdullah, Wan Omar

    2016-01-01

    In the tropics, there are too few studies on isolation of Blastocystis sp. subtypes from water sources; in addition, there is also an absence of reported studies on the occurrence of Blastocystis sp. subtypes in water during different seasons. Therefore, this study was aimed to determine the occurrence of Blastocystis sp. subtypes in river water and other water sources that drained aboriginal vicinity of highly endemic intestinal parasitic infections during wet and dry seasons. Water samples were collected from six sampling points of Sungai Krau (K1–K6) and a point at Sungai Lompat (K7) and other water sources around the aboriginal villages. The water samples were collected during both seasons, wet and dry seasons. Filtration of the water samples were carried out using a flatbed membrane filtration system. The extracted DNA from concentrated water sediment was subjected to single round polymerase chain reaction and positive PCR products were subjected to sequencing. All samples were also subjected to filtration and cultured on membrane lactose glucuronide agar for the detection of faecal coliforms. During wet season, Blastocystis sp. ST1, ST2 and ST3 were detected in river water samples. Blastocystis sp. ST3 occurrence was sustained in the river water samples during dry season. However Blastocystis sp. ST1 and ST2 were absent during dry season. Water samples collected from various water sources showed contaminations of Blastocystis sp. ST1, ST2, ST3 and ST4, during wet season and Blastocystis sp. ST1, ST3, ST8 and ST10 during dry season. Water collected from all river sampling points during both seasons showed growth of Escherichia coli and Enterobacter aerogenes, indicating faecal contamination. In this study, Blastocystis sp. ST3 is suggested as the most robust and resistant subtype able to survive in any adverse environmental condition. Restriction and control of human and animal faecal contaminations to the river and other water sources shall prevent the

  13. Nanocomposites Based on Water Glass Matrix as a Foundry Binder: Chosen Physicochemical Properties

    Directory of Open Access Journals (Sweden)

    Kmita A.

    2017-03-01

    Full Text Available The nanocomposites based on water glass matrix were attempted in the study. Nanoparticles of ZnO, Al2O3 or MgO in organic solutions were applied into water glass matrix in the amounts of: 1.5; 3; 4 or 5 mas. %. Wettability of the quartz sad by the nanocomposites based on water glass matrix was determined by testing changes of the wetting angle θ in time τ for the system: quartz - binder in non-stationary state, by means of the device for measuring wetting angles. Wettability measurements were carried out under isothermal conditions at an ambient temperature (20 - 25°C. The modification improves wettability of quartz matrix by water glass, which is effective in improving strength properties of hardened moulding sands. Out of the considered modifiers in colloidal solution of propyl alcohol water glass modified by MgO nanoparticles indicated the smallest values of the equilibrium wetting angle θr. This value was equal app. 11 degrees and was smaller no less than 40 degrees than θr value determined for not modified water glass. Viscosity η of nanocomposites based on water glass matrix was determined from the flow curve, it means from the empirically determined dependence of the shearing stress τ on shear rate γ: τ = f (γ (1, by means of the rotational rheometer. Measurements were carried out at a constant temperature of 20°C. The modification influences the binder viscosity. This influence is conditioned by: amount of the introduced modifier as well as dimensions and kinds of nanoparticles and organic solvents. The viscosity increase of the modified binder does not negatively influence its functional properties.

  14. Thermodynamic properties of water solvating biomolecular surfaces

    Science.gov (United States)

    Heyden, Matthias

    Changes in the potential energy and entropy of water molecules hydrating biomolecular interfaces play a significant role for biomolecular solubility and association. Free energy perturbation and thermodynamic integration methods allow calculations of free energy differences between two states from simulations. However, these methods are computationally demanding and do not provide insights into individual thermodynamic contributions, i.e. changes in the solvent energy or entropy. Here, we employ methods to spatially resolve distributions of hydration water thermodynamic properties in the vicinity of biomolecular surfaces. This allows direct insights into thermodynamic signatures of the hydration of hydrophobic and hydrophilic solvent accessible sites of proteins and small molecules and comparisons to ideal model surfaces. We correlate dynamic properties of hydration water molecules, i.e. translational and rotational mobility, to their thermodynamics. The latter can be used as a guide to extract thermodynamic information from experimental measurements of site-resolved water dynamics. Further, we study energy-entropy compensations of water at different hydration sites of biomolecular surfaces. This work is supported by the Cluster of Excellence RESOLV (EXC 1069) funded by the Deutsche Forschungsgemeinschaft.

  15. Grey water impact on soil physical properties

    Directory of Open Access Journals (Sweden)

    Miguel L. Murcia-Sarmiento

    2014-01-01

    Full Text Available Due to the increasing demand for food produced by the increase in population, water as an indispensable element in the growth cycle of plants every day becomes a fundamental aspect of production. The demand for the use of this resource is necessary to search for alternatives that should be evaluated to avoid potential negative impacts. In this paper, the changes in some physical properties of soil irrigated with synthetic gray water were evaluated. The experimental design involved: one factor: home water and two treatments; without treated water (T1 and treated water (T2. The variables to consider in the soil were: electrical conductivity (EC, exchangeable sodium percentage (ESP, average weighted diameter (MWD and soil moisture retention (RHS. The water used in drip irrigation high frequency was monitored by tensiometer for producing a bean crop (Phaseolous vulgaris L. As filtration system used was employed a unit composed of a sand filter (FLA and a subsurface flow wetland artificial (HFSS. The treatments showed significant differences in the PSI and the RHS. The FLA+HFSS system is an alternative to the gray water treatment due to increased sodium retention.

  16. Transport properties of supercooled confined water

    Science.gov (United States)

    Mallamace, F.; Branca, C.; Broccio, M.; Corsaro, C.; Gonzalez-Segredo, N.; Spooren, J.; Stanley, H. E.; Chen, S.-H.

    2008-07-01

    This article presents an overview of recent experiments performed on transport properties of water in the deeply supercooled region, a temperature region of fundamental importance in the science of water. We report data of nuclear magnetic resonance, quasi-elastic neutron scattering, Fourier-transform infrared spectroscopy, and Raman spectroscopy, studying water confined in nanometer-scale environments. When contained within small pores, water does not crystallise, and can be supercooled well below its homogeneous nucleation temperature Th. On this basis it is possible to carry out a careful analysis of the well known thermodynamical anomalies of water. Studying the temperature and pressure dependencies of water dynamics, we show that the liquid-liquid phase transition (LLPT) hypothesis represents a reliable model for describing liquid water. In this model, water in the liquid state is a mixture of two different local structures, characterised by different densities, namely the low density liquid (LDL) and the high-density liquid (HDL). The LLPT line should terminate at a special transition point: a low-T liquid-liquid critical point. We discuss the following experimental findings on liquid water: (i) a crossover from non-Arrhenius behaviour at high T to Arrhenius behaviour at low T in transport parameters; (ii) a breakdown of the Stokes-Einstein relation; (iii) the existence of a Widom line, which is the locus of points corresponding to maximum correlation length in the p-T phase diagram and which ends in the liquid-liquid critical point; (iv) the direct observation of the LDL phase; (v) a minimum in the density at approximately 70 K below the temperature of the density maximum. In our opinion these results represent the experimental proofs of the validity of the LLPT hypothesis.

  17. Water retention curves and thermal insulating properties of Thermosand

    Science.gov (United States)

    Leibniz, Otto; Winkler, Gerfried; Birk, Steffen

    2010-05-01

    The heat loss and the efficiency of isolating material surrounding heat supply pipes are essential issues for the energy budget of heat supply pipe lines. Until now heat loss from the pipe is minimized by enlarging the polyurethane (PU) - insulation thickness around the pipe. As a new approach to minimize the heat loss a thermally insulating bedding material was developed and investigated. Conventional bedding sands cover all necessary soil mechanical properties, but have a high thermal conductivity from λ =1,5 to 1,7 W/(m K). A newly developed embedding material 'Thermosand' shows thermal properties from λ=0,18 W/(m K) (dry) up to 0,88 W/(m K) (wet). The raw material originates from the waste rock stockpiles of a coal mine near Fohnsdorf, Austria. With high temperatures up to nearly 1000 ° C and a special mineral mixture, a natural burned reddish material resembling clinker arises. The soilmechanical properties of Thermosand has been thoroughly investigated with laboratory testing and in situ investigations to determine compaction-, permeability- and shear-behaviour, stiffness and corresponding physical parameters. Test trenches along operational heat pipes with temperature-measurement along several cross-sections were constructed to compare conventional embedding materials with 'Thermosand'. To investigate the influence of varying moisture content on thermal conductivity a 1:1 large scale model test in the laboratory to simulate real insitu-conditions was established. Based on this model it is planned to develop numerical simulations concerning varying moisture contents and unsaturated soil mechanics with heat propagation, including the drying out of the soil during heat input. These simulations require the knowledge about the water retention properties of the material. Thus, water retention curves were measured using both steady-state tension and pressure techniques and the simplified evaporation method. The steady-state method employs a tension table (sand

  18. Water saturation phase of the buffer and backfill in the KBS-3V concept. Special emphasis given to the influence of the backfill on the wetting of the buffer

    Energy Technology Data Exchange (ETDEWEB)

    Boergesson, Lennart; Faelth, Billy [Clay Technology AB, Lund (Sweden); Hernelind, Jan [5T Engineering AB, Vaesteraas (Sweden)

    2006-08-15

    The wetting and rate of saturation of the buffer and backfill materials in a KBS- V repository from the rock fractures and the rock matrix have been investigated by a large number of different finite element models and calculations. For most models the FE-code ABAQUS has been used but for investigation of the influence of trapped air in the backfill FE-code Code Bright was used. Both codes include completely coupled THM models, which have been used, but for some calculations it has been sufficient to limit the models to only use the hydraulic or thermohydraulic parts of the models. The following analyses have been made: 1. The influence of the backfill properties and wetting conditions on the water saturation phase of the buffer has been investigated with the old FEM-model used in earlier wetting calculations for SR-97. The old calculations have been updated regarding the influence of the backfill. The model is 2-dimensional with axial symmetry around the axis of the deposition hole. These calculations show that there is strong influence of wetting from the backfill if the rock is rather dry (K{sub rock} = 10{sup -13} m/s), while the influence is low if the rock is rather wet (K{sub rock} = 10{sup -12} m/s). At K{sub rock} = 10{sup -13} m/s the time to saturation decreases with a factor 2 in the absence of fractures and with a factor 1.5 with two fractures intersecting the hole when water is supplied from the backfill (30/70) compared to when no water is available. A completely dry rock yields very long time to saturation and of course decisive influence of the water supply from the backfill. If water is freely available at a water pressure of 5 MPa in the backfill it takes 250-500 years to reach full saturation of the buffer. If the water available in the backfill is limited to the initial amount (completely dry rock also around the tunnel and thus no addition of water from the rock in the tunnel) it will take several thousands years to reach some kind of

  19. Evaluation of Empirical Tropospheric Models Using Satellite-Tracking Tropospheric Wet Delays with Water Vapor Radiometer at Tongji, China

    OpenAIRE

    Miaomiao Wang; Bofeng Li

    2016-01-01

    An empirical tropospheric delay model, together with a mapping function, is commonly used to correct the tropospheric errors in global navigation satellite system (GNSS) processing. As is well-known, the accuracy of tropospheric delay models relies mainly on the correction efficiency for tropospheric wet delays. In this paper, we evaluate the accuracy of three tropospheric delay models, together with five mapping functions in wet delays calculation. The evaluations are conducted by comparing ...

  20. Impact of Wet Deposition of Black Carbon on Particle Dynamics in Surface Waters of Halong Bay, North Vietnam

    Science.gov (United States)

    Mari, X.; Guinot, B. P.; Thuoc, C. V.; Brune, J.; Lefebvre, J. P.; Raimbault, P.; Niggemann, J.; Dittmar, T.

    2016-02-01

    Black Carbon (BC) is an aerosol emitted during biomass burning and fossil fuel combustion. The atmospheric lifetime of Black Carbon (BC) ranges from a few days in rainy climates up to one month in dry regions, and on a global scale wet deposition of atmospheric BC accounts for about 80% of the BC input to the ocean. The rain-mediated input of BC to the ocean was studied in a coastal site located in a regional hotspot of atmospheric BC concentration, North Vietnam. We monitored changes in atmospheric and marine BC during a 24-h cycle impacted by a short and heavy rainfall event. During the rainfall event, atmospheric BC concentration decreased by a factor of 8 (i.e. from 5230 to 660 µg BC m-3). This cleaning of the air column was immediately followed by a significant increase (by a factor of 2 to 4) of particulate BC (PBC) and POC concentrations in the surface microlayer (SML) and at 1.5 m depth. In the SML, this event was also followed by a significant increase of DOC and dissolved BC (DBC) concentrations. Interestingly, the concentration of DOC decreased by >10% after the rainfall at 1.5 m depth, suggesting an adsorption of DOC onto sinking PBC. Concomitantly with the increase in particulate BC, nutrient concentrations increased by a factor of 2 in the SML, while no change was observed in the underlying water column. After the rainfall, the particle size spectra, measured along the water column with a LISST (Laser In-Situ Scattering and Transmissometry probe), changed in that the concentration of small particles (100 µm) increased. This alteration of the particle size spectra was restricted to a thin layer of about 20 cm thickness, probably corresponding to a BC-enriched layer adsorbing DOC and small particles, and stimulating aggregation during sinking from the surface to deeper water layers. The concentrations of POC, DOC, PBC, DBC and nutrients reached pre-rainfall levels 4 hours after the event.

  1. Topographical Anisotropy and Wetting of Ground Stainless Steel Surfaces

    Directory of Open Access Journals (Sweden)

    Cornelia Bellmann

    2012-12-01

    Full Text Available Microscopic and physico-chemical methods were used for a comprehensive surface characterization of different mechanically modified stainless steel surfaces. The surfaces were analyzed using high-resolution confocal microscopy, resulting in detailed information about the topographic properties. In addition, static water contact angle measurements were carried out to characterize the surface heterogeneity of the samples. The effect of morphological anisotropy on water contact angle anisotropy was investigated. The correlation between topography and wetting was studied by means of a model of wetting proposed in the present work, that allows quantifying the air volume of the interface water drop-stainless steel surface.

  2. Energy and exergy analysis of counter flow wet cooling towers

    Directory of Open Access Journals (Sweden)

    Saravanan Mani

    2008-01-01

    Full Text Available Cooling tower is an open system direct contact heat exchanger, where it cools water by both convection and evaporation. In this paper, a mathematical model based on heat and mass transfer principle is developed to find the outlet condition of water and air. The model is solved using iterative method. Energy and exergy analysis infers that inlet air wet bulb temperature is found to be the most important parameter than inlet water temperature and also variation in dead state properties does not affect the performance of wet cooling tower. .

  3. Isotopic analysis of dissolved organic carbon in produced water brines by wet chemical oxidation and cavity ring-down spectroscopy

    Science.gov (United States)

    Thomas, Randal; Conaway, Christopher; Saad, Nabil; Kharaka, Yousif

    2013-04-01

    Identification of fluid migration and escape from intentionally altered subsurface geologic systems, such as in hydraulic fracturing, enhanced oil recovery, and carbon sequestration activities, is an important issue for environmental regulators based on the traction that the "fracking" process is gathering across the United States. Given diverse injected fluid compositions and the potential for toxic or regulated compounds to be released, one of the most important steps in the process is accurately identifying evidence of injected fluid escape during and after injection processes. An important tool in identifying differences between the natural groundwater and injected fluid is the isotopic composition of dissolved constituents including inorganic components such as Sr and carbon isotopes of the dissolved organic compounds. Since biological processes in the mesothermal subsurface can rapidly alter the organic composition of a fluid, stable carbon isotopes of the dissolved organic compounds (DOC) are an effective means to identify differences in the origin of two fluids, especially when coupled with inorganic compound analyses. The burgeoning field of cavity ring-down spectroscopy (CRDS) for isotopic analysis presents an opportunity to obtain rapid, reliable and cost-effective isotopic measurements of DOC in potentially affected groundwater for the identification of leakage or the improvement of hydrogeochemical pathway models. Here we adapt the use of the novel hyphenated TOC-CRDS carbon isotope analyzer for the analysis of DOC in produced water by wet oxidation and describe the methods to evaluate performance and obtain useful information at higher salinities. Our methods are applied to a specific field example in a CO2-enhanced EOR field in Cranfield, Mississippi (USA) as a means to demonstrate the ability to distinguish natural and injected DOC using the stable isotopic composition of the dissolved organic carbon when employing the novel TOC-CRDS instrumentation

  4. Retrieval of Wet-Tropospheric Path Delay over Coastal and Inland Water Regions using Wide-band Millimeter-Wave Radiometry

    Science.gov (United States)

    Bosch-Lluis, Xavier; Gilliam, Kyle L.; Reising, Steven C.; Tanner, Alan B.; Brown, Shannon T.; Kangaslahti, Pekka

    2013-04-01

    Currently, wet-tropospheric path delay measurements over inland water and coastal areas are extremely sparse. They are generally limited to twice-per-day radiosonde launches and a small number of ground-based GPS or radiometer path delay measurements, as well as radar measurements of phase delay to a small number of fixed targets on the ground. Knowledge of the wet-tropospheric path delay is necessary for next-generation high-resolution altimeters, such as the Surface Water and Ocean Topography (SWOT) mission, in formulation and planned for launch in 2020. SWOT has two major science objectives. First, the oceanographic objective is to characterize ocean mesoscale and sub-mesoscale circulation with horizontal resolution of 10 km and order of 1 cm height precision. Second, the hydrological objective is to provide global height measurements of inland surface water bodies with area of greater than 250 square meters and flow rate of rivers with width greater than 100 m. Wet-tropospheric path delay retrieval over coastal and inland-water areas is needed to achieve both of these objectives with sufficient height accuracy. In addition, information on total precipitable water vapor under nearly all weather conditions is needed to improve initialization of numerical weather prediction models. Currently, 18-34 GHz microwave radiometers provide wet-path delay corrections for the Jason series of nadir-viewing altimeters. However, these retrievals are limited to open ocean, and land incursion is unacceptable within 40 km of coastlines. The addition of millimeter-wave radiometers (70-170 GHz) is needed to address this problem by providing smaller surface footprint dimensions proportional to wavelength. In this work, we present a prototype algorithm to demonstrate the potential to retrieve wet-tropospheric path delay from brightness temperatures measured by millimeter-wave radiometers using the Brightness Temperature Deflection Ratio (BTDR) method. The BTDR algorithm retrieves wet

  5. Comparison of the chemical properties of wheat straw and beech fibers following alkaline wet oxidation and laccase treatments

    DEFF Research Database (Denmark)

    Schmidt, A. S.; Mallon, S.; Thomsen, Anne Belinda;

    2002-01-01

    Wheat straw (Triticum aestivum) and beech (Fagus sylvatica), were used to evaluate the effects of two pre-treatment processes (alkaline wet oxidation and enzyme treatment with laccase) on lignocellulosic materials for applications in particleboards and fiberboards. Wheat straw and beech fibers...... reacted differently in the two processes. The chemical composition changed little following enzyme treatment. After alkaline wet oxidation, fibers enriched in cellulose were obtained. With both materials, almost all hemicellulose (80%) together with a large portion of the lignin were solubilised...... by alkaline wet oxidation, but essentially all cellulose remained in the solid fraction. Following enzyme treatment most material remained as a solid. For wheat straw, reaction with acetic anhydride indicated that both treatments resulted in more hydroxyl groups being accessible for reaction. The enzyme...

  6. Effect of water absorption on the mechanical properties of cotton fabric-reinforced geopolymer composites

    Directory of Open Access Journals (Sweden)

    T. Alomayri

    2014-09-01

    Full Text Available Cotton fabric (CF reinforced geopolymer composites are fabricated with fibre loadings of 4.5, 6.2 and 8.3 wt%. Results show that flexural strength, flexural modulus, impact strength, hardness and fracture toughness are increased as the fibre content increased. The ultimate mechanical properties were achieved with a fibre content of 8.3 wt%. The effect of water absorption on mechanical and physical properties of CF reinforced geopolymer composites is also investigated. The magnitude of maximum water uptake and diffusion coefficient is increased with an increase in fibre content. Flexural strength, modulus, impact strength, hardness and fracture toughness values are decreased as a result of water absorption. Scanning electron microscopy (SEM is used to characterise the microstructure and failure mechanisms of dry and wet cotton fibre reinforced geopolymer composites.

  7. Effects of surface coating process conditions on the water permeation and salt rejection properties of composite polyamide reverse osmosis membranes

    KAUST Repository

    Louie, Jennifer Sarah

    2011-02-01

    The application of polymer surface coatings to improve the fouling resistance of reverse osmosis membranes tends to increase flow resistance across the membrane. This paper presents a systematic analysis on how membrane properties and performance are impacted by the coating process steps, and investigates how such effects could contribute to lower water flux. On one hand, simply pre-soaking dry aromatic polyamide composite membranes in aliphatic alcohols results in a significant increase in water flux, which is attributed to wetting of pores in the selective polyamide layer and to changes in the polymer structure. This flux increase was not readily reversible, based on a 300-h water permeation test. Conversely, drying a wetted membrane led to a decrease in water flux, which we hypothesize is caused by increased interchain hydrogen-bonding in the selective layer. This drop in water flux was not permanent; higher flux was observed if the same wetted/dried membrane was then re-soaked in ethanol prior to the water permeation experiment. An ethanol pre-soaking step also increased water flux of a PEBAX-coated membrane by nearly 70%. In contrast to the reduction in water flux caused by the specific treatment sequence of ethanol-swelling followed by drying, this same sequence actually increased gas transport. The eight- to ten-fold increase in Knudsen diffusion-based gas permeance after this pre-treatment was attributed to an increase in the number or size of membrane defects. © 2010 Elsevier B.V.

  8. Modeling Relations Among Relative Permeabilities, Fluid Saturations, and Capillary Pressures in Mixed-Wet Porous Media: Model Testing and Application to Oil-Water Systems

    Energy Technology Data Exchange (ETDEWEB)

    Oostrom, Mart (BATTELLE (PACIFIC NW LAB)); Lenhard, Robert J.(INEEL); Delshad, M; Robertson, S D.(Spirit 76, Midland, TX); M.Th. van Genuchten, F.J. Leij and L. Wu

    1998-01-01

    A critical component of all multiphase flow codes is how relationships among relative permeabilities, fluid saturations, and capillary pressures (i.e., k-S-P relations) are described. Models that are able to mimic fundamental fluid-flow processes to predict k S-P relations are preferable than extrapolating measured data points to estimate k-S-P relations because they may have greater utility and may be more consistent. Furthermore, different saturation-path histories may be simulated with a computer code than those measured in the k-S-P experiments. Because the geometry of the pore spaces in natural porous media is very complex and will likely never be precisely known to predict k-S-P behavior from fundamental relationships, k-S-P models are largely empirical. In this paper, an empirical model based on theoretical considerations is developed to predict hysteretic k-S-P relations in porous media in which the smaller pores are water-wet and the larger pores are oil-wet, i.e., mixed-w et. At high oil-water capillary pressures, the water saturation is modeled to approach the residual water saturation. At low oil-water capillary pressures (i.e., negative), the oil saturation is modeled to approach the residual oil saturation. Relative permeabilities are predicted using parameters that describe main-drainage S-P relations and accounting for the distribution of water and oil in the pore spaces of mixed-wet porous media. The proposed algebraic expressions are easy to implement in multiphase flow codes and can be used to predict k-S-P relations for any saturation-path history. In addition, the model is relatively easy to calibrate to porous media.

  9. The Modification of Sodium Polyacrylate Water Solution Cooling Properties by AL2O3

    Directory of Open Access Journals (Sweden)

    Wojciech Gęstwa

    2010-01-01

    Based on cooling curves, it can be concluded that for the water solution of sodium polyacrylate with AL2O3 nanoparticles in comparison to water and 10% polymer water solution lower cooling speed is obtained. The cooling medium containing nanoparticles provides lower cooling speed in the smallest surface austenite occurance (500–600 C in the charts of the CTP for most nonalloy structural steels and low-alloy steels. However lower cooling temperature at the beginning of martensitic transformation causes the formation of smaller internal stresses, leading to smaller dimensional changes and hardening deformation. For the quenching media the wetting angle was appointed by the drop-shape method. These studies showed the best wettability of polymer water solution (sodium polyacrylate with the addition of AL2O3 nanoparticles, whose wetting angle was about 65 degrees. Obtaining the smallest wetting angle for the medium containing nanoparticles suggests that the heat transfer to the cooling medium is larger. This allows slower cooling at the same time ensuring its homogeneity. The obtained values of wetting angle confirm the conclusions drawn on the basis of cooling curves and allowus to conclude that in the case of the heat transfer rate it will have a lower value than for water and 10% polymer water solution. In the research on hardened carburized steel samples C10 and 16MnCr5 surface hardness, impact strength and changes in the size of cracks in Navy C-ring sample are examined. On this basis of the obtained results it can be concluded that polymer water solution with nanoparticles allows to obtain a better impact strength at comparable hardness on the surface. Research on the dimensional changes on the basis of the sample of Navy C-ring also shows small dimensional changes for samples carburized and hardened in 10% polymer water solution with the addition of nanoparticles AL2O3. Smaller dimensional changes were obtained for samples of steel 16MnCr5 thanfar C10. The

  10. Land application of mine water causes minimal uranium loss offsite in the wet-dry tropics: Ranger Uranium Mine, Northern Territory, Australia.

    Science.gov (United States)

    Mumtaz, Saqib; Streten, Claire; Parry, David L; McGuinness, Keith A; Lu, Ping; Gibb, Karen S

    2015-11-01

    Ranger Uranium Mine (RUM) is situated in the wet-dry tropics of Northern Australia. Land application (irrigation) of stockpile (ore and waste) runoff water to natural woodland on the mine lease is a key part of water management at the mine. Consequently, the soil in these Land Application Areas (LAAs) presents a range of uranium (U) and other metals concentrations. Knowledge of seasonal and temporal changes in soil U and physicochemical parameters at RUM LAAs is important to develop suitable management and rehabilitation strategies. Therefore, soil samples were collected from low, medium, high and very high U sites at RUM LAAs for two consecutive years and the effect of time and season on soil physicochemical parameters particularly U and other major solutes applied in irrigation water was measured. Concentrations of some of the solutes applied in the irrigation water such as sulphur (S), iron (Fe) and calcium (Ca) showed significant seasonal and temporal changes. Soil S, Fe and Ca concentration decreased from year 1 to year 2 and from dry to wet seasons during both years. Soil U followed the same pattern except that we recorded an increase in soil U concentrations at most of the RUM LAAs after year 2 wet season compared to year 2 dry season. Thus, these sites did not show a considerable decrease in soil U concentration from year 1 to year 2. Sites which contained elevated U after wet season 2 also had higher moisture content which suggests that pooling of U containing rainwater at these sites may be responsible for elevated U. Thus, U may be redistributed within RUM LAAs due to surface water movement. The study also suggested that a decrease in U concentrations in LAA soils at very high U (>900 mg kg(-1)) sites is most likely due to transport of particulate matter bound U by surface runoff and U may not be lost from the surface soil due to vertical movement through the soil profile. Uranium attached to particulate matter may reduce its potential for environmental

  11. [Anomalous Properties of Water and Aqueous Solutions at Low Temperatures].

    Science.gov (United States)

    Matsumoto, Masakazu

    2015-01-01

    Water has many anomalous properties below the room temperature. The temperature range overlaps with that of the Earth's atmosphere and also with that natural life forms favor. We review the origin of the anomalous properties of water and aqueous solutions in association with the hypothetical second critical point and liquid-liquid phase separation of water hidden in the supercooled state of liquid water.

  12. Development, calibration, and performance of a novel biocrust wetness probe (BWP) measuring the water content of biological soil crusts and surface soils

    Science.gov (United States)

    Weber, Bettina; Berkemeier, Thomas; Ruckteschler, Nina; Caesar, Jennifer; Ritter, Holger; Heintz, Henno; Brass, Henning

    2015-04-01

    The surface layer of soils as transition zone between pedosphere and atmosphere plays a crucial role in exchange processes of nutrients, atmospheric gases and water. In arid and semiarid regions, this uppermost soil layer is commonly colonized by biological soil crusts (biocrusts), which cover about 46 million km2 worldwide being highly relevant in the global terrestrial carbon and nitrogen cycles. Their water status is of major concern, as activity of these poikilohydric organisms is directly controlled by their water content. On-site analyses of both bare and crusted soils thus are urgently needed to correctly model exchange processes of water, nutrients and trace gases at the soil surface. In this study we present the biocrust wetness probe (BWP), which is the first low-cost sensor to reliably measure the water content within biocrusts or the uppermost 5 mm of the substrate. Using a weak alternating current, the electrical conductivity is assessed and an automatic calibration routine allows calculating the water content and precipitation equivalent of the surface layer over time. During one year of continuous field measurements, 60 BWPs were installed in different types of biocrusts and bare soil to measure at 5-minute intervals in the Succulent Karroo, South Africa. All sensors worked reliably and responded immediately and individually upon precipitation events. Upon completion of field measurements, soil and biocrust samples were collected from all measurement spots to compile calibration curves in the lab. In most soil and biocrust samples the water content rose linearly with increasing electrical conductivity values and only for few samples an exponential relationship was observed. Measurements revealed characteristic differences in biocrust and soil wetness patterns, which affect both the water regime and physiological processes in desert regions. Thus BWPs turned out to be well suited sensors for spatio-temporal monitoring of soil water content, allowing

  13. Climate-Determined Suitability of the Water Saving Technology "Alternate Wetting and Drying" in Rice Systems: A Scalable Methodology demonstrated for a Province in the Philippines.

    Directory of Open Access Journals (Sweden)

    Andrew Nelson

    Full Text Available 70% of the world's freshwater is used for irrigated agriculture and demand is expected to increase to meet future food security requirements. In Asia, rice accounts for the largest proportion of irrigated water use and reducing or conserving water in rice systems has been a long standing goal in agricultural research. The Alternate Wetting and Drying (AWD technique has been developed to reduce water use by up to 30% compared to the continuously flooded conditions typically found in rice systems, while not impacting yield. AWD also reduces methane emissions produced by anaerobic archae and hence has applications for reducing water use and greenhouse gas emissions. Although AWD is being promoted across Asia, there have been no attempts to estimate the suitable area for this promising technology on a large scale. We present and demonstrate a spatial and temporal climate suitability assessment method for AWD that can be widely applied across rice systems in Asia. We use a simple water balance model and easily available spatial and temporal information on rice area, rice seasonality, rainfall, potential evapotranspiration and soil percolation rates to assess the suitable area per season. We apply the model to Cagayan province in the Philippines and conduct a sensitivity analysis to account for uncertainties in soil percolation and suitability classification. As expected, the entire dry season is climatically suitable for AWD for all scenarios. A further 60% of the wet season area is found suitable contradicting general perceptions that AWD would not be feasible in the wet season and showing that spatial and temporal assessments are necessary to explore the full potential of AWD.

  14. Effect of water absorption on the mechanical properties of nanoclay filled recycled cellulose fibre reinforced epoxy hybrid nanocomposites

    KAUST Repository

    Alamri, H.

    2013-01-01

    Recycled cellulose fibre (RCF) reinforced epoxy/clay nanocomposites were successfully synthesized with different weight percentages (0%, 1%, 3% and 5%) of organoclay platelets (30B). The objective of this study was to investigate the effect of water absorption on the physical and mechanical properties of the RCF reinforced epoxy/clay nanocomposites. TEM images indicated a well-intercalated structure of nanoclay/epoxy matrix with some exfoliated regions. Water absorption was found to decrease as the clay content increased. The flexural strength, flexural modulus and fracture toughness significantly decreased as a result of water absorption. However, the properties of impact strength and impact toughness were found to increase after exposing to water. The addition of nanoclay slightly minimized the effect of moisture on the mechanical properties. SEM images showed that water absorption severely damaged the cellulose fibres and the bonding at fibres-matrix interfaces in wet composites. © 2012 Elsevier Ltd. All rights reserved.

  15. 关于湿法熄焦系统中水锤现象防护的比较%Measures for water hammer prevention in wet quenching system

    Institute of Scientific and Technical Information of China (English)

    张春才; 张晓光

    2014-01-01

    介绍了水锤现象的成因、危害、机理及防护措施,通过对比分析国内几种典型湿法熄焦工艺中水锤现象的防护措施,发现在熄焦水泵出口选用缓闭止回阀,在熄焦水输送管道中部选用自动液力阀,可防止湿法熄焦系统中水锤现象发生。%With description of the cause , harmfulness , mechanism and prevention measures against water hammer , and by analyzing several typical measures for water hammer prevention in wet quenching system ,this paper concluded that delay-close check valve can be selected at the outlet of quenching pump and automatic hydraulic pump can be used on the pipeline carrying quenching water so that the water hammer can be effectively avoided in the wet quenching process .

  16. STUDY ON PROPERTIES OF DISFECTING WET WIPER%一种消毒湿巾性能的试验研究

    Institute of Scientific and Technical Information of China (English)

    刘小娟; 周庆; 冯磊; 蔡曙光

    2011-01-01

    Objective To study the germicidal efficacy and related properties of disinfecting wet wiper. Methods Carrier quantitative germicidal test and animal test were used to observe the disinfection properties of wet wiper both in laboratory and on the spot. Results The disinfecting wiper was made up of o - phenylphenol and o - benzyl - p - chlorophenol.The average killing rates of Staphylococcus aureus and Escherichia coli in the suspension soaking the disinfecting wet wiper for 10 minutes both achieved 100%. The 20% (V/V) FBS had no influence on germicidal efficacy. In animal tests of the dermal irritation test and the skin sensitization test, the rabbits had no erythema or edema. The disinfecting wet wiper had no irritation to the intact skin of rabbit. Conclusion The disinfecting wet wiper has good germicidal efficacy and has no irritation to intact skin. The organic substances have little influence on it.%目的 观察一种消毒湿巾的杀菌效果及其消毒相关性能.方法 采用载体定量杀菌试验法和动物试验法,对该消毒湿巾进行了实验室和现场试验.结果 该消毒湿巾是用邻苯基苯酚与邻苄基对氯酚复配制剂浸渍制成.在消毒湿巾上直接污染细菌,浸透作用10 min,对金黄色葡萄球菌和大肠杆菌平均杀灭率均达到100%.体积分数20%小牛血清,对该消毒湿巾杀菌效果基本无影响.用该消毒湿巾湿敷实验动物皮肤,均未出现红斑及水肿现象,完整皮肤刺激反应积分为0,属无刺激性.结论 该消毒湿巾杀菌效果良好,受有机物影响小,对完整皮肤无刺激性.

  17. Sticky or Slippery Wetting: Network Formation Conditions Can Provide a One-Way Street for Water Flow on Platinum-cured Silicone.

    Science.gov (United States)

    Wang, Chenyu; Nair, Sithara S; Veeravalli, Sharon; Moseh, Patricia; Wynne, Kenneth J

    2016-06-01

    In the course of studies on Sylgard 184 (S-PDMS), we discovered strong effects on receding contact angles (CAs), θrec, while cure conditions have little effect on advancing CAs. Network formation at high temperatures resulted in high θadv of 115-120° and high θrec ≥ 80°. After network formation at low temperatures (≤25 °C), θadv was still high but θrec was 30-50°. Uncertainty about compositional effects on wetting behavior resulted in similar experiments with a model D(V)D(H) silicone elastomer (Pt-PDMS) composed of a vinyl-terminated poly(dimethylsiloxane) (PDMS) base and a polymeric hydromethylsilane cross-linker. Again, network formation at high temperature (∼100 °C) resulted in high CAs, while low-temperature curing retained high advancing CAs but gave low receding CAs (θrec 30-50°). These changes in receding CAs translate to strong effects on water adhesion, wp, which is the actual work required to separate a liquid (water) from a surface: wp ∝ (1 + θrec). When the values θrec 84° for high-temperature and θrec 50° for low-temperature network formation are used, wp is ∼1.5 times higher for curing at low temperature. The origin of low receding contact angles was investigated by attenuated total reflectance IR spectroscopy. Absorptions for Si-OH hydrogen-bonded to water (3350 cm(-1)) were stronger for low- versus high-temperature curing. This result is attributed to faster hydrosilylation during curing at higher temperatures that consumes Si-H before autoxidation to Si-OH. Sharp bands at 3750 and 3690 cm(-1) due to isolated -Si-OH are more prominent for Pt-PDMS than those for S-PDMS, which may be due to an effect of functionalized nanofiller. To explore the impact of wp on water droplet flow, gradient coatings of S-PDMS and Pt-PDMS elastomers were prepared by coating a slide, maintaining opposite ends at high and low temperatures and thus forming a thermal gradient. When the slide was tilted, a droplet moved easily on the high

  18. Study of the mechanical properties of welded joints by wet sub sea welding technique with tubular electrode; Estudo das propriedades mecanicas de juntas soldadas pela tecnica de soldagem subaquatica molhada com eletrodo tubular

    Energy Technology Data Exchange (ETDEWEB)

    Teichmann, Erwin Werner; Baixo, Carlos Eduardo Iconomos; Dutra, Jair Carlos [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica. Lab. de Soldagem e Mecatronica - LABSOLDA]. E-mail: erwin@labsolda.ufsc.br; Santos, Valter Rocha dos [Centro Federal de Educacao Tecnologica (CEFET), Rio de Janeiro, RJ (Brazil); Teixeira, Jose Claudio [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    1997-07-01

    Some experiments conducted at LABSOLDA/UFSC - a welding laboratory of Santa Catarina Univ., Florianopolis, Brazil - in order to identify mechanical properties, weld bead geometry and the quantity and dimensions of pores in weld beads produced by sub sea wet FCAW are described. Welding in shallow water with power source adjusted to operate in constant current characteristic mode and a set of parameters to establish an open arc transfer mode it was obtained weld beads with regular geometry and an acceptable profile, with low level of defects incidence, no pores and crack free. The tenacity measured by Charpy tests (0C) was 34 J and hardness of 119 HV-10 measured by Vickers tests. The methodology used in the experiments and the results obtained are discussed in the paper. (author)

  19. Relationship between mechanical properties of one-step self-etch adhesives and water sorption.

    Science.gov (United States)

    Hosaka, Keiichi; Nakajima, Masatoshi; Takahashi, Masahiro; Itoh, Shima; Ikeda, Masaomi; Tagami, Junji; Pashley, David H

    2010-04-01

    The purpose of this study was to evaluate the relationship between changes in the modulus of elasticity and ultimate tensile strength of one-step self-etch adhesives, and their degree of water sorption. Five one-step self-etch adhesives, Xeno IV (Dentsply Caulk), G Bond (GC Corp.), Clearfil S3 Bond (Kuraray Medical Inc.), Bond Force (Tokuyama Dental Corp.), and One-Up Bond F Plus (Tokuyama Dental Corp.) were used. Ten dumbelled-shaped polymers of each adhesive were used to obtain the modulus of elasticity by the three-point flexural bending test and the ultimate tensile strength by microtensile testing. The modulus of elasticity and the ultimate tensile strength were measured in both dry and wet conditions before/after immersion in water for 24h. Water sorption was measured, using a modification of the ISO-4049 standard. Each result of the modulus of elasticity and ultimate tensile strength was statistically analyzed using a two-way ANOVA and the result of water sorption was statistically analyzed using a one-way ANOVA. Regression analyses were used to determine the correlations between the modulus of elasticity and the ultimate tensile strength in dry or wet states, and also the percent decrease in these properties before/after immersion of water vs. water sorption. In the dry state, the moduli of elasticity of the five adhesive polymers varied from 948 to 1530 MPa, while the ultimate tensile strengths varied from 24.4 to 61.5 MPa. The wet specimens gave much lower moduli of elasticity (from 584 to 1073 MPa) and ultimate tensile strengths (from 16.5 to 35.0 MPa). Water sorption varied from 32.1 to 105.8 g mm(-3). The moduli of elasticity and ultimate tensile strengths of the adhesives fell significantly after water-storage. Water sorption depended on the constituents of the adhesive systems. The percent decreases in the ultimate tensile strengths of the adhesives were related to water sorption, while the percent reductions in the moduli of elasticity of the

  20. Physico-chemical properties of perturbed water: facts and enigmas

    Directory of Open Access Journals (Sweden)

    Vittorio Elia

    2012-09-01

    Full Text Available Background The study of extremely diluted and agitated substances and solutions is strictly linked with the analysis of properties of water perturbed using different systems. This study is about the determination of the physical-chemical parameters of water, after the perturbations described. Methods The perturbed water was obtained using the three different protocols: · EDS (Extremely Diluted Solutions. Obtained through an iterative process of successive dilutions and agitations. · IFW (Iteratively Filtered Water. Obtained through an iterative process of successive filtrations through sintered glass filters. · INW (Iteratively Nafionized Water. Obtained through an iterative process of successive drying and wetting of the Nafion polymer. The parameters under study are: electrical conductivity, χ / μS cm-1; heat of mixing with acid (HCl, ΔQmixHCl / J Kg-1 or basic (NaOH solutions, ΔQmixNaOH / J Kg-1 and pH. χ increases of up to two orders of magnitude, ΔQmixNaOH / J Kg-1 is exothermic and increases as the electrical conductivity increases, with a roughly linear trend, up to one order of magnitude. The analogous ΔQmixHCl / J Kg-1, on the contrary, is found to be exothermic or null depending on the protocol used. For the two protocol (EDS or IFW the pH is alkaline while for the third one (INW is quite acid and shows a very good linear correlation with logχ. The linear correlations hint at a single cause for the variation of the three very different physical- chemical parameters. Results and discussion Each protocol produces water exhibiting its own peculiarities, to the point that they can be considered different, albeit with the common element of a variation of the super-molecular structure of the water solvent. These three procedures capable of affecting water can be grouped together by means of a common work

  1. C++ Implementation of IAPWS Water/Steam Properties

    Energy Technology Data Exchange (ETDEWEB)

    Ling Zou; Haihua Zhao; Hongbin Zhang; Qiyue Lu

    2014-02-01

    For the calculations of water-involved systems, such as safety analysis of light water reactors, it is essential to provide accurate water properties. The International Association for the Properties of Water and Steam is an international non-profit association of national organizations concerned with the properties of water and steam. It provides internationally accepted formulations of water/steam properties for scientific and industrial applications. The purpose of this work is to provide a stand-alone software package in C++ programming language to provide accurate and efficient water/steam properties evaluation, based on the latest IAPWS releases. The discussion on related IAPWS releases, code implementations and verifications are provided in details.

  2. Investigation of the Influence of PLA Molecular Structure on the Crystalline Forms (α’ and α and Mechanical Properties of Wet Spinning Fibres

    Directory of Open Access Journals (Sweden)

    Michał Puchalski

    2017-01-01

    Full Text Available In this paper, the influence of the molecular structure of polylactide (PLA—characterised by its molar mass and content of d-lactide isomer—on the molecular ordering and α’–α form transition during fibre manufacturing by the wet spinning method is described. Fibres were studied by wide-angle X-ray diffraction (WAXD and differential scanning calorimetry (DSC. Additionally, the physical and mechanical properties of the fibres were determined. This study also examines the preliminary molecular ordering and crystallisation of PLA fibres at various draw ratios. The performed experiments clearly show the dependence of the molecular ordering of PLA on the molar mass and d-lactide content during the wet spinning process. The fibres manufactured from PLA with the lowest content of d-lactide and the lowest molar mass were characterised by a higher tendency for crystallisation and a higher possibility to undergo the disorder-to-order phase transition (α’ to α form. The structural changes in PLA explain the observed changes in the physical and mechanical properties of the obtained fibres.

  3. Water masses and property distribution in the EEZ of Mauritius

    Digital Repository Service at National Institute of Oceanography (India)

    DeSousa, S.N.; Singbal, S.Y.S.; George, M.D.

    Water masses and their properties have been studied in the Mauritian during September-October, 1987. Surface water is characterizEd. by two water masses: 1) a warm (temp. 27 degrees C) and relatively saline water (salinity 35.3 x 10 sup(-3)) which...

  4. Optical backscattering properties of the "clearest" natural waters

    Directory of Open Access Journals (Sweden)

    M. S. Twardowski

    2007-07-01

    Full Text Available During the BIOSOPE field campaign October–December 2004, measurements of inherent optical properties from the surface to 500 m depth were made with a ship profiler at stations covering over ~8000 km through the Southeast Pacific Ocean. Data from a ~3000 km section containing the very clearest waters in the central gyre are reported here. The total volume scattering function at 117°, βt(117°, was measured with a WET Labs ECO-BB3 sensor at 462, 532, and 650 nm with estimated uncertainties of 2×10−5, 5×10−6, and 2×10−6 m−1 sr−1, respectively. These values were approximately 6%, 3%, and 3% of the scattering by pure seawater at their respective wavelengths. From a methodological perspective, there were several results:

    bbp distributions were resolvable even though some of the values from the central gyre were an order of magnitude lower than the lowest previous measurements in the literature;
    – Direct in-situ measurements of instrument dark offsets were necessary to accurately resolve backscattering at these low levels;
    – accurate pure seawater backscattering values are critical in determining particulate backscattering coefficients in the open ocean (not only in these very clear waters; the pure water scattering values determined by Buiteveld et al. (1994 with a [1 + 0.3S/37] adjustment for salinity based on Morel (1974 appear to be the most accurate estimates, with aggregate accuracies as low as a few percent; and
    – closure was demonstrated with subsurface reflectance measurements reported by Morel et al. (2007 within instrument precisions, a useful factor in validating the backscattering measurements.

    This methodology enabled several observations with respect to the hydrography and the use of backscattering as a biogeochemical proxy:

    – The clearest waters sampled were found at

  5. Optical backscattering properties of the "clearest" natural waters

    Directory of Open Access Journals (Sweden)

    M. S. Twardowski

    2007-11-01

    Full Text Available During the BIOSOPE field campaign October–December 2004, measurements of inherent optical properties from the surface to 500 m depth were made with a ship profiler at stations covering over 8000 km through the Southeast Pacific Ocean. Data from a ~3000 km section containing the very clearest waters in the central gyre are reported here. The total volume scattering function at 117°, βt(117°, was measured with a WET Labs ECO-BB3 sensor at 462, 532, and 650 nm with estimated uncertainties of 2×10-5, 5×10-6, and 2×10-6 m−1 sr−1, respectively. These values were approximately 6%, 3%, and 3% of the volume scattering by pure seawater at their respective wavelengths. From a methodological perspective, there were several results:

    – distributions were resolvable even though some of the values from the central gyre were an order of magnitude lower than the lowest previous measurements in the literature;
    – Direct in-situ measurements of instrument dark offsets were necessary to accurately resolve backscattering at these low levels;
    – accurate pure seawater backscattering values are critical in determining particulate backscattering coefficients in the open ocean (not only in these very clear waters; the pure water scattering values determined by Buiteveld et al. (1994 with a [1+0.3S/37] adjustment for salinity based on Morel (1974 appear to be the most accurate estimates, with aggregate accuracies as low as a few percent; and
    – closure was demonstrated with subsurface reflectance measurements reported by Morel et al. (2007 within instrument precisions, a useful factor in validating the backscattering measurements.

    This methodology enabled several observations with respect to the hydrography and the use of backscattering as a biogeochemical proxy:

    –The clearest waters sampled were found at depths between 300 and 350 m, from 23.5° S

  6. Surface state modulation through wet chemical treatment as a route to controlling the electrical properties of ZnO nanowire arrays investigated with XPS

    Energy Technology Data Exchange (ETDEWEB)

    Lord, Alex M., E-mail: a.m.lord@swansea.ac.uk [Centre for Nanohealth, College of Engineering, University of Swansea, Singleton Park, SA2 8PP (United Kingdom); Maffeis, Thierry G. [Multidisciplinary Nanotechnology Centre, College of Engineering, University of Swansea, Singleton Park, SA2 8PP (United Kingdom); Allen, Martin W. [MacDiarmid Institute for Advanced Materials and Nanotechnology, University of Canterbury, Private Bag 4800, Christchurch, 8014 (New Zealand); Morgan, David; Davies, Philip R. [Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Park Place, Cardiff, CF10 3AT (United Kingdom); Jones, Daniel R.; Evans, Jonathan E. [Multidisciplinary Nanotechnology Centre, College of Engineering, University of Swansea, Singleton Park, SA2 8PP (United Kingdom); Smith, Nathan A.; Wilks, Steve P. [Multidisciplinary Nanotechnology Centre, Department of Physics, College of Science, University of Swansea, Singleton Park, SA2 8PP (United Kingdom)

    2014-11-30

    Highlights: • Direct measurement of the surface band bending exhibited by ZnO nanowires using monochromatic XPS. • Modulation of the surface depletion region using wet chemical treatment (EtOH, H{sub 2}O{sub 2}). • The measured surface potential barrier agrees with electrical measurements of individual nanowires. • H{sub 2}O{sub 2} depletes the nanowire of charge carriers while EtOH donates electrons at the surface. • EtOH has the effect of restoring the surface potential barrier of oxidised nanowires. - Abstract: ZnO is a wide bandgap semiconductor that has many potential applications including solar cell electrodes, transparent thin film transistors and gas/biological sensors. Since the surfaces of ZnO materials have no amorphous or oxidised layers, they are very environmentally sensitive, making control of their semiconductor properties challenging. In particular, the electronic properties of ZnO nanostructures are dominated by surface effects while surface conduction layers have been observed in thin films and bulk crystals. Therefore, the ability to use the ZnO materials in a controlled way depends on the development of simple techniques to modulate their surface electronic properties. Here, we use monochromatic x-ray photoelectron spectroscopy (XPS) to investigate the use of different wet chemical treatments (EtOH, H{sub 2}O{sub 2}) to control the electronic properties of ZnO nanowires by modulating the surface depletion region. The valence band and core level XPS spectra are used to explore the relationship between the surface chemistry of the nanowires and the surface band bending.

  7. Bio-Inspired Extreme Wetting Surfaces for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Sera Shin

    2016-02-01

    Full Text Available Biological creatures with unique surface wettability have long served as a source of inspiration for scientists and engineers. More specifically, materials exhibiting extreme wetting properties, such as superhydrophilic and superhydrophobic surfaces, have attracted considerable attention because of their potential use in various applications, such as self-cleaning fabrics, anti-fog windows, anti-corrosive coatings, drag-reduction systems, and efficient water transportation. In particular, the engineering of surface wettability by manipulating chemical properties and structure opens emerging biomedical applications ranging from high-throughput cell culture platforms to biomedical devices. This review describes design and fabrication methods for artificial extreme wetting surfaces. Next, we introduce some of the newer and emerging biomedical applications using extreme wetting surfaces. Current challenges and future prospects of the surfaces for potential biomedical applications are also addressed.

  8. Methods of analysis by the U.S. Geological Survey National Water Quality Laboratory : determination of nonpurgeable suspended organic carbon by wet-chemical oxidation and infrared spectrometry

    Science.gov (United States)

    Burkhardt, Mark R.; Kammer, James A.; Jha, Virendra K.; O'Mara-Lopez, Peggy G.; Woodworth, Mark T.

    1997-01-01

    Precision and accuracy results are described for the determination of nonpurgeable suspended organic carbon (SOC) by silver-filter filtration, wet-chemical oxidation, and infrared determination of hte resulting carbon dioxide (CO2) used at the U.S. Geological Survey's nationalWater Quality Laboratory. An aliquot of raw water isfiltered through a 0.45-micrometer silver filter. The trapped organic material is oxidized using phosphoric acid and potassium persulfate in a scaled glass ampule,and the rseulting CO2 is measured by an infrared CO2 detector. The amount of CO3 is proportional to the concentration of chemically oxidizable nonpurgeable organic carbon in the sample. The SOC method detection limit for routine analysis is 0.2 milligram per liter. The average percent recovery is 97.1 percent and the average standard deviation is 11 percent.

  9. Subcritical and supercritical water oxidation of organic, wet wastes for carbon cycling in regenerative life support systems

    Science.gov (United States)

    Ronsse, Frederik; Lasseur, Christophe; Rebeyre, Pierre; Clauwaert, Peter; Luther, Amanda; Rabaey, Korneel; Zhang, Dong Dong; López Barreiro, Diego; Prins, Wolter; Brilman, Wim

    2016-07-01

    For long-term human spaceflight missions, one of the major requirements is the regenerative life support system which has to be capable of recycling carbon, nutrients and water from both solid and liquid wastes generated by the crew and by the local production of food through living organisms (higher plants, fungi, algae, bacteria, …). The European Space Agency's Life Support System, envisioned by the MELiSSA project, consists of a 5 compartment artificial ecosystem, in which the waste receiving compartment (so-called compartment I or briefly 'CI') is based on thermophilic fermentation. However, as the waste generated by the crew compartment and food production compartment contain typical plant fibres (lignin, cellulose and hemicellulose), these recalcitrant fibres end up largely unaffected in the digestate (sludge) generated in the C-I compartment. Therefore, the C-I compartment has to be supplemented with a so-called fibre degradation unit (in short, FDU) for further oxidation or degradation of said plant fibres. A potential solution to degrading these plant fibres and other recalcitrant organics is their oxidation, by means of subcritical or supercritical water, into reusable CO2 while retaining the nutrients in an organic-free liquid effluent. By taking advantage of the altered physicochemical properties of water above or near its critical point (647 K, 22.1 MPa) - including increased solubility of non-polar compounds and oxygen, ion product and diffusivity - process conditions can be created for rapid oxidation of C into CO2. In this research, the oxidizer is provided as a hydrogen peroxide solution which, at elevated temperature, will dissociated into O2. The purpose of this study is to identify ideal process conditions which (a) ensure complete oxidation of carbon, (b) retaining the nutrients other than C in the liquid effluent and (c) require as little oxidizer as possible. Experiments were conducted on a continuous, tubular heated reactor and on batch

  10. Strong disorder renewal approach to DNA denaturation and wetting: typical and large deviation properties of the free energy

    Science.gov (United States)

    Monthus, Cécile

    2017-01-01

    For the DNA denaturation transition in the presence of random contact energies, or equivalently the disordered wetting transition, we introduce a strong disorder renewal approach to construct the optimal contacts in each disordered sample of size L. The transition is found to be of infinite order, with a correlation length diverging with the essential singularity \\ln ξ (T)\\propto |T-{{T}\\text{c}}{{|}-1} . In the critical region, we analyze the statistics over samples of the free-energy density f L and of the contact density, which is the order parameter of the transition. At the critical point, both decay as a power-law of the length L but remain distributed, in agreement with the general phenomenon of lack of self-averaging at random critical points. We also obtain that for any real q  >  0, the moment \\overline{ZLq} of order q of the partition function at the critical point is dominated by some exponentially rare samples displaying a finite free-energy density, i.e. by the large deviation sector of the probability distribution of the free-energy density.

  11. "Breath figures" on leaf surfaces-formation and effects of microscopic leaf wetness.

    Science.gov (United States)

    Burkhardt, Juergen; Hunsche, Mauricio

    2013-01-01

    "Microscopic leaf wetness" means minute amounts of persistent liquid water on leaf surfaces which are invisible to the naked eye. The water is mainly maintained by transpired water vapor condensing onto the leaf surface and to attached leaf surface particles. With an estimated average thickness of less than 1 μm, microscopic leaf wetness is about two orders of magnitude thinner than morning dewfall. The most important physical processes which reduce the saturation vapor pressure and promote condensation are cuticular absorption and the deliquescence of hygroscopic leaf surface particles. Deliquescent salts form highly concentrated solutions. Depending on the type and concentration of the dissolved ions, the physicochemical properties of microscopic leaf wetness can be considerably different from those of pure water. Microscopic leaf wetness can form continuous thin layers on hydrophobic leaf surfaces and in specific cases can act similar to surfactants, enabling a strong potential influence on the foliar exchange of ions. Microscopic leaf wetness can also enhance the dissolution, the emission, and the reaction of specific atmospheric trace gases e.g., ammonia, SO2, or ozone, leading to a strong potential role for microscopic leaf wetness in plant/atmosphere interaction. Due to its difficult detection, there is little knowledge about the occurrence and the properties of microscopic leaf wetness. However, based on the existing evidence and on physicochemical reasoning it can be hypothesized that microscopic leaf wetness occurs on almost any plant worldwide and often permanently, and that it significantly influences the exchange processes of the leaf surface with its neighboring compartments, i.e., the plant interior and the atmosphere. The omission of microscopic water in general leaf wetness concepts has caused far-reaching, misleading conclusions in the past.

  12. Influence of sputtering conditions on the optical and electrical properties of laser-annealed and wet-etched room temperature sputtered ZnO:Al thin films

    Energy Technology Data Exchange (ETDEWEB)

    Boukhicha, Rym, E-mail: rym.boukhicha@polytechnique.edu [CNRS, LPICM, Ecole Polytechnique, 91128 Palaiseau (France); Charpentier, Coralie [CNRS, LPICM, Ecole Polytechnique, 91128 Palaiseau (France); Total S and M — New Energies Division, R and D Division, Department of Solar Energies EN/BO/RD/SOL, Tour Michelet, 24 cours Michelet, La Défense 10, 92069 Paris La Défense Cedex (France); Prod' Homme, Patricia [Total S and M — New Energies Division, R and D Division, Department of Solar Energies EN/BO/RD/SOL, Tour Michelet, 24 cours Michelet, La Défense 10, 92069 Paris La Défense Cedex (France); Roca i Cabarrocas, Pere [CNRS, LPICM, Ecole Polytechnique, 91128 Palaiseau (France); Lerat, Jean-François; Emeraud, Thierry [Photovoltaic Business Unit, Excico Group NV, Kempische Steenweg 305/2, B-3500 Hasselt (Belgium); Johnson, Erik [CNRS, LPICM, Ecole Polytechnique, 91128 Palaiseau (France)

    2014-03-31

    We explore the influence of the sputtering deposition conditions on the outcome of an excimer laser anneal and chemical etching process with the goal of producing highly textured substrates for thin film silicon solar cells. Aluminum-doped zinc oxide (ZnO:Al) thin films were prepared on glass substrates by radio frequency magnetron sputtering from a ceramic target at room temperature. The effects of the process pressure (0.11–1.2 Pa) and oxygen flow (0–2 sccm) on the optical and electrical properties of ZnO:Al thin films have been studied both before and after an excimer laser annealing treatment followed by a dilute HCl chemical etch. The as-deposited films varied from completely opaque to yellowish. Thin film laser annealing dramatically improves the optical properties of the most opaque thin films. After laser annealing at the optimum fluence, the average transmittance in the visible wavelength range was around 80% for most films, and reasonable electrical performance was obtained for the films deposited at lower pressures and without oxygen flux (7 Ω/□ for films of 1 μm). After etching, all films displayed a dramatic improvement in haze, but only the low pressure, low oxygen films retained acceptable electrical properties (< 11 Ω/□). - Highlights: • Al:ZnO thin films were deposited at room temperature. • The ZnO:Al films were excimer laser annealed and then wet-etched. • The optical and electrical properties were studied in details.

  13. Wetting agent investigation for controlling dust of lead-zinc ores

    Institute of Scientific and Technical Information of China (English)

    WU Chao; PENG Xiao-lan; WU Guo-min

    2007-01-01

    The purpose of this project is to control the pollution of dust, which occurred in a typical lead-zinc mine. Two kinds of surfactants and water glass were chosen as the wetting agents to study the behaviours of suppressing the dust. The performances of the wetting agents of various sizes and water content of dust and their compositions among different weting agents were investigated. Firstly, the chemical compounds, dispersity, water content, bulk density and other relevant physico-chemical properties of the choiced dust of lead-zinc ore were mensurated. A great number of down-ward penetrating tests were conducted to different partical sizes of dust and to analyze the dust wetting behaviour respectively. The optimal compositions of wetting agents were obtained in accordance with different water contents and partical sizes of the dust after analyzing and statisting the achieved experimental data. The data show that the efficiency of chemical dust suppression of weting agents is much better than that of water. The results of the research work prove that the partical size and the water content of the dust are very important factors to the dust suppression. The results are also proved validly by the dropping experiment, which takes the penetrating diameter and penetrating time as the major factors. The superfine dust is much more difficult to be wetted. Since increasing the water content of dust is the best approach to control it, the choice of wetting agents for improving dispensation is significant.

  14. The exchange of energy, water and carbon dioxide between wet arctic tundra and the atmosphere at the Lena River Delta, Northern Siberia

    Energy Technology Data Exchange (ETDEWEB)

    Kutzbach, L.

    2006-07-01

    The ecosystem-scale exchange fluxes of energy, water and carbon dioxide between wet arctic tundra and the atmosphere were investigated by the micrometeorological eddy covariance method. The investigation site was the centre of the Lena River Delta in Northern Siberia characterised by a polar and distinctly continental climate, very cold and ice-rich permafrost and its position at the interface between the Eurasian continent and the Arctic Ocean. The measurements were performed on the surface of a Holocene river terrace characterised by wet polygonal tundra. The soils at the site are characterised by high organic matter content, low nutrient availability and pronounced water logging. The vegetation is dominated by sedges and mosses. The fluctuations of the H{sub 2}O and CO{sub 2} concentrations were measured with a closed-path infrared gas analyser. The fast-response eddy covariance measurements were supplemented by a set of slow-response meteorological and soil-meteorological measurements. The combined datasets of the two campaigns 2003 and 2004 were used to characterise the seasonal course of the energy, water and CO{sub 2} fluxes and the underlying processes for the synthetic measurement period May 28..October 21 2004/2003 including the period of snow and soil thawing as well as the beginning of refreezing. The synthetic measurement period 2004/2003 was characterised by a long snow ablation period and a late start of the growing season. On the other hand, the growing season ended also late due to high temperatures and snow-free conditions in September. The cumulative summer energy partitioning was characterised by low net radiation, large ground heat flux, low latent heat flux and very low sensible heat flux compared to other tundra sites. These findings point out the major importance of the very cold permafrost for the summer energy budget of the tundra in Northern Siberia. (orig./SR)

  15. Effect of a Trace of Bi and Ni on the Microstructure and Wetting Properties of Sn-Zn-Cu Lead-Free Solder

    Institute of Scientific and Technical Information of China (English)

    Haitao MA; Haiping XIE; Lai WANG

    2007-01-01

    The microstructure and melting behavior of Sn-9Zn-2Cu (SZC) lead-free solder with 3 wt pct Bi and various amount of Ni additions were studied. The wetting properties and the interracial reaction of Sn-Zn-Cu with Cu substrate were also examined. The results indicated that the addition of 3 wt pct Bi could decrease the melting point of the solder and Ni would refine the microstructure and the rod-shape Cu5Zn8 phase changed into square-shape (Cu, Ni)5Zn8 phase. The addition of Bi, Ni greatly improved the wettability of SZC solder.In addition, the interfacial phase of the solders/Cu joint was typical planar Cu5Zn8 in SZC-3Bi-INi alloy.

  16. Predictions of the properties of water from first principles

    NARCIS (Netherlands)

    Bukowski, R.; Szalewicz, K.; Groenenboom, G.C.; Avoird, A. van der

    2007-01-01

    A force field for water has been developed entirely from first principles, without any fitting to experimental data. It contains both pairwise and many-body interactions. This force field predicts the properties of the water dimer and of liquid water in excellent agreement with experiments, a previo

  17. Refinement and carbon incorporation effects on the superconducting properties of MgB{sub 2} through wet milling process of low purity boron powder

    Energy Technology Data Exchange (ETDEWEB)

    Jun, Byung-Hyuk, E-mail: bhjun@kaeri.re.kr [Neutron Science Division, Korea Atomic Energy Research Institute (KAERI), Daejeon 305-353 (Korea, Republic of); Park, Soon-Dong; Kim, Chan-Joong [Neutron Science Division, Korea Atomic Energy Research Institute (KAERI), Daejeon 305-353 (Korea, Republic of)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Wet milling effects of B powder on the superconducting properties were investigated. Black-Right-Pointing-Pointer The C substitution for the B site in MgB{sub 2} occurred due to a toluene medium. Black-Right-Pointing-Pointer A shift of MgB{sub 2} peaks in XRD and a variation of J{sub c}-B slopes proved C incorporation. Black-Right-Pointing-Pointer The B particle size reduction could induce a small grain size in the MgB{sub 2} formation. Black-Right-Pointing-Pointer J{sub c} and H{sub c2} were enhanced by increased grain boundary pinning and lattice disorder. - Abstract: The wet milling effects of boron (B) powder on the full width at half maximum (FWHM) value of X-ray reflexes, grain size, carbon (C) substitution, critical temperature (T{sub c}), critical current density (J{sub c}), irreversibility field (H{sub irr}), and upper critical field (H{sub c2}) have been investigated for MgB{sub 2} bulk superconductors. The semi-crystalline B powder with a low purity of 95-97% was refined with different milling times of 1 to 15 h using a toluene medium. As a result of B powder milling, the particle size of the B powder decreased and the semi-crystalline phase became an amorphous phase. As the milling time increased, T{sub c} of MgB{sub 2} bulk decreased by the deterioration of the crystallinity and J{sub c} increased over the applied magnetic fields. With the refinement of the B powder, the grain boundary pinning increased due to smaller MgB{sub 2} grain size. In addition, it was found that a C substitution for the B site occurred from a toluene medium during wet milling process. The increased electron scattering due to an increase of the defects like grain boundary and lattice disorder by C substitution led to enhance the superconducting properties with an increase of the FWHM value of the MgB{sub 2} peaks and a decrease of the T{sub c}. The MgB{sub 2} prepared from B powder mechanically milled for 7 h showed the highest magnetic

  18. The trade of virtual water: do property rights matter?

    Science.gov (United States)

    Xu, Ankai

    2016-04-01

    My paper examines the determinants of the virtual water trade - embodied in the trade of agriculture products - by estimating a structural gravity model. In particular, it tests the relationship between property rights and the export of water-intensive agricultural products based on water footprint data in Mekonnen and Hoekstra (2011, 2012). Using two different measures of property rights protection, I show that countries with weaker property rights have an apparent comparative advantage in the trade of water-intensive products. After controlling for the economic size, natural resource endowments, and possible effects of reverse causality, the trade flow of virtual water is negatively and significantly correlated with the property rights index of the exporting country. Holding other factors constant, one point increase in the property rights index of a country is associated with a 24% - 36% decrease in its virtual water export, whereas a 1% increase in the natural resource protection index of a country is associated with a 16% decrease in its virtual water export. This paper is the first empirical work that tests the relationship between property rights and trade of water-intensive products, offering a new perceptive in the debate of virtual water trade. The findings provide a possible explanation on the paradoxical evidence that some countries with scarce water resources export water-intensive products. The result is important not only in terms of its theoretical relevance, but also its policy implications. As prescribed by the model of trade and property rights, when countries with weaker property rights open to international trade, they are more likely to over-exploit and thus expedite the depletion of natural resources.

  19. Drop splashing is independent of substrate wetting

    CERN Document Server

    Latka, Andrzej; Nagel, Sidney R; de Pablo, Juan J

    2016-01-01

    A liquid drop impacting a dry solid surface with sufficient kinetic energy will splash, breaking apart into numerous secondary droplets. This phenomenon shows many similarities to forced wetting, including the entrainment of air at the contact line. Because of these similarities and the fact that forced wetting has been shown to depend on the wetting properties of the surface, existing theories predict splashing to depend on wetting properties as well. However, using high-speed interference imaging we observe that wetting properties have no effect on splashing for various liquid-surface combinations. Additionally, by fully resolving the Navier-Stokes equations at length and time scales inaccessible to experiments, we find that the shape and motion of the air-liquid interface at the contact line are independent of wettability. We use these findings to evaluate existing theories and to compare splashing with forced wetting.

  20. Identifying overarching excipient properties towards an in-depth understanding of process and product performance for continuous twin-screw wet granulation.

    Science.gov (United States)

    Willecke, N; Szepes, A; Wunderlich, M; Remon, J P; Vervaet, C; De Beer, T

    2017-02-14

    The overall objective of this work is to understand how excipient characteristics influence the process and product performance for a continuous twin-screw wet granulation process. The knowledge gained through this study is intended to be used for a Quality by Design (QbD)-based formulation design approach and formulation optimization. A total of 9 preferred fillers and 9 preferred binders were selected for this study. The selected fillers and binders were extensively characterized regarding their physico-chemical and solid state properties using 21 material characterization techniques. Subsequently, principal component analysis (PCA) was performed on the data sets of filler and binder characteristics in order to reduce the variety of single characteristics to a limited number of overarching properties. Four principal components (PC) explained 98.4% of the overall variability in the fillers data set, while three principal components explained 93.4% of the overall variability in the data set of binders. Both PCA models allowed in-depth evaluation of similarities and differences in the excipient properties.

  1. Phoenix's Wet Chemistry Lab

    Science.gov (United States)

    2008-01-01

    This is an illustration of the analytical procedure of NASA's Phoenix Mars Lander's Wet Chemistry Lab (WCL) on board the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument. By dissolving small amounts of soil in water, WCL can determine the pH, the abundance of minerals such as magnesium and sodium cations or chloride, bromide and sulfate anions, as well as the conductivity and redox potential. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  2. Phoenix's Wet Chemistry Lab

    Science.gov (United States)

    2008-01-01

    This is an illustration of soil analysis on NASA's Phoenix Mars Lander's Wet Chemistry Lab (WCL) on board the Microscopy, Electrochemistry, and Conductivity Analyzer (MECA) instrument. By dissolving small amounts of soil in water, WCL will attempt to determine the pH, the abundance of minerals such as magnesium and sodium cations or chloride, bromide and sulfate anions, as well as the conductivity and redox potential. The Phoenix Mission is led by the University of Arizona, Tucson, on behalf of NASA. Project management of the mission is by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Spacecraft development is by Lockheed Martin Space Systems, Denver.

  3. Early Mars was wet but not warm: Erosion, fluvial features, liquid water habitats, and life below freezing

    Science.gov (United States)

    Mckay, C. P.; Davis, W. L.

    1993-01-01

    There is considerable evidence that Mars had liquid water early in its history and possibly at recurrent interval. It has generally been assumed that this implied that the climate was warmer as a result of a thicker CO2 atmosphere than at the present. However, recent models suggest that Mars may have had a thick atmosphere but may not have experienced mean annual temperatures above freezing. In this paper we report on models of liquid water formation and maintenance under temperatures well below freezing. Our studies are based on work in the north and south polar regions of Earth. Our results suggest that early Mars did have a thick atmosphere but precipitation and hence erosion was rare. Transient liquid water, formed under temperature extremes and maintained under thick ice covers, could account for the observed fluvial features. The main difference between the present climate and the early climate was that the total surface pressure was well above the triple point of water.

  4. Exploiting interfacial water properties for desalination and purification applications.

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Hongwu (Los Alamos National Laboratory, Los Alamos, NM); Varma, Sameer; Nyman, May Devan; Alam, Todd Michael; Thuermer, Konrad; Holland, Gregory P.; Leung, Kevin; Liu, Nanguo (University of New Mexico Albuquerque, NM); Xomeritakis, George K. (University of New Mexico Albuquerque, NM); Frankamp, Benjamin L.; Siepmann, J. Ilja (University of Minnesota, Minneapolis, MN); Cygan, Randall Timothy; Hartl, Monika A. (Los Alamos National Laboratory, Los Alamos, NM); Travesset, Alex (Iowa State University, Ames, IA); Anderson, Joshua A. (Iowa State University, Ames, IA); Huber, Dale L.; Kissel, David J. (University of New Mexico Albuquerque, NM); Bunker, Bruce Conrad; Lorenz, Christian Douglas; Major, Ryan C. (University of Minnesota, Minneapolis, MN); McGrath, Matthew J. (University of Minnesota, Minneapolis, MN); Farrow, Darcie; Cecchi, Joseph L. (University of New Mexico Albuquerque, NM); van Swol, Frank B.; Singh, Seema; Rempe, Susan B.; Brinker, C. Jeffrey; Clawson, Jacalyn S.; Feibelman, Peter Julian; Houston, Jack E.; Crozier, Paul Stewart; Criscenti, Louise Jacqueline; Chen, Zhu (University of New Mexico Albuquerque, NM); Zhu, Xiaoyang (University of Minnesota, Minneapolis, MN); Dunphy, Darren Robert (University of New Mexico Albuquerque, NM); Orendorff, Christopher J.; Pless, Jason D.; Daemen, Luke L. (Los Alamos National Laboratory, Los Alamos, NM); Gerung, Henry (University of New Mexico Albuquerque, NM); Ockwig, Nathan W.; Nenoff, Tina Maria; Jiang, Ying-Bing; Stevens, Mark Jackson

    2008-09-01

    A molecular-scale interpretation of interfacial processes is often downplayed in the analysis of traditional water treatment methods. However, such an approach is critical for the development of enhanced performance in traditional desalination and water treatments. Water confined between surfaces, within channels, or in pores is ubiquitous in technology and nature. Its physical and chemical properties in such environments are unpredictably different from bulk water. As a result, advances in water desalination and purification methods may be accomplished through an improved analysis of water behavior in these challenging environments using state-of-the-art microscopy, spectroscopy, experimental, and computational methods.

  5. Microbial community composition of transiently wetted Antarctic Dry Valley soils

    Directory of Open Access Journals (Sweden)

    Thomas D. Neiderberger

    2015-01-01

    Full Text Available During the summer months, wet (hyporheic soils associated with ephemeral streams and lake edges in the Antarctic Dry Valleys (DV become hotspots of biological activity and are hypothesized to be an important source of carbon and nitrogen for arid DV soils. Recent research in the DV has focused on the geochemistry and microbial ecology of lakes and arid soils, with substantially less information being available on hyporheic soils. Here we determined the unique properties of hyporheic microbial communities, resolved their relationship to environmental parameters and to compared them to archetypal arid DV soils. Generally, pH increased and chlorophyll a concentrations decreased along transects from wet to arid soils (9.0 to ~7.0 for pH and ~0.8 to ~ 5 µg/cm3 for chlorophyll a, respectively. Soil water content decreased to below ~3% in the arid soils. Community fingerprinting-based principle component analyses revealed that bacterial communities formed distinct clusters specific to arid and wet soils; however, eukaryotic communities that clustered together did not have similar soil moisture content nor did they group together based on sampling location. Collectively, rRNA pyrosequencing indicated a considerably higher abundance of Cyanobacteria in wet soils and a higher abundance of Acidobacterial, Actinobacterial, Deinococcus/Thermus, Bacteroidetes, Firmicutes, Gemmatimonadetes, Nitrospira and Planctomycetes in arid soils. The two most significant differences at the genus level were Gillisia signatures present in arid soils and chloroplast signatures related to Streptophyta that were common in wet soils. Fungal dominance was observed in arid soils and Viridplantae were more common in wet soils. This research represents an in-depth characterization of microbial communities inhabiting wet DV soils. Results indicate that the repeated wetting of hyporheic zones has a profound impact on the bacterial and eukaryotic communities inhabiting in these areas.

  6. The Status of Water in Swelling Shales: An Insight from the Water Retention Properties of the Callovo-Oxfordian Claystone

    Science.gov (United States)

    Menaceur, Hamza; Delage, Pierre; Tang, Anh Minh; Talandier, Jean

    2016-12-01

    The Callovo-Oxfordian (COx) claystone is considered in France as a possible host rock for the disposal of high-level long-lived radioactive waste at great depth. During the operational phase, the walls of the galleries and of the disposal cells will be successively subjected to desaturation induced by ventilation followed by resaturation once the galleries are closed. To better understand this phenomenon, a sound understanding of the water retention properties of the COx claystone is necessary. Following a previous study by the same group, this paper presents an investigation of microstructure changes in COx claystone under suction changes. Microstructure was investigated by means of mercury intrusion porosimetry tests on freeze-dried specimens previously submitted to various suctions. Along the drying path, the initial microstructure, characterised by a well-classified unimodal pore population around a mean diameter value of 32 nm, slightly changed with the same shape of the PSD curve and slightly moved towards smaller diameters (27-28 nm) at suctions of 150 and 331 MPa, respectively. The infra-porosity too small to be intruded by mercury (diameter smaller than 5.5 nm) reduced from 4.3 to 3.3 %. Oven drying reduced the mean diameter to 20 nm and the infra-porosity to 1 %. Wetting up to 9 MPa suction leads to saturation with no significant change in the PSD curve, whereas wetting at zero suction gave rise to the appearance of a large pore population resulting from the development of cracks with width of several micrometres, together with an enlargement of the initial pore population above the mean diameter. The concepts describing the step hydration of smectites (by the successive placement within the clay platelets along the smectite faces of 1, 2, 3 and 4 layers of water molecules with respect to the suction applied) appeared relevant to better understand the changes in microstructure of the COx claystone under suction changes. This also allowed to better define

  7. The measurement and research of thermal-wet comfort properties of textiles under reverse temperature field conditions%逆温差条件下织物热湿舒适性的测试与研究

    Institute of Scientific and Technical Information of China (English)

    姚穆; 李毅; 李顺东; 施楣梧

    2001-01-01

    The thermal-wet comfort proprties of textiles under the conditions that the environment temperature is higher than that of human body (called “reverse temperature field”) are examined in this paper.Four quanties (i.e.equivalent thermal resistance,thermal resistance,resistance to water vapour transmission and air permeability) were suggested as the physical indexes of thermal-wet comfort properties of textiles under this condition.Their special meanings under this condition were explained also.The Colthing Microclimate Testing Meter was used to determine the indexes of seven different kinds of textiles.The statistical analysis was applied to analyse the relationship between these indexes and the results from wearing-clothing test.Some elementary results were obtained.%研究了在环境温度高于人体体表温度(称逆温差)条件下,服装用织物的热湿舒适性能,提出使用当量热阻、热阻、湿阻及透气率作为在此条件下织物的热湿舒适性物理指标,指出了在此条件下其特殊含义.并且用织物微气候仪测试了此条件下7种织物的热湿舒适性指标,与对比穿着试验的结果进行了分析,得出了一些初步规律.

  8. Soil water repellency changes with depth and relationship to physical properties within wettable and repellent soil profiles

    Directory of Open Access Journals (Sweden)

    Sepehrnia Nasrollah

    2017-03-01

    Full Text Available This study explored the effect of soil water repellency (SWR on soil hydrophysical properties with depth. Soils were sampled from two distinctly wettable and water repellent soil profiles at depth increments from 0-60 cm. The soils were selected because they appeared to either wet readily (wettable or remain dry (water repellent under field conditions. Basic soil properties (MWD, SOM, θv were compared to hydrophysical properties (Ks, Sw, Se, Sww, Swh, WDPT, RIc, RIm and WRCT that characterise or are affected by water repellency. Our results showed both soil and depth affected basic and hydrophysical properties of the soils (p <0.001. Soil organic matter (SOM was the major property responsible for water repellency at the selected depths (0-60. Water repellency changes affected moisture distribution and resulted in the upper layer (0-40 cm of the repellent soil to be considerably drier compared to the wettable soil. The water repellent soil also had greater MWDdry and Ks over the entire 0-60 cm depth compared to the wettable soil. Various measures of sorptivity, Sw, Se, Sww, Swh, were greater through the wettable than water repellent soil profile, which was also reflected in field and dry WDPT measurements. However, the wettable soil had subcritical water repellency, so the range of data was used to compare indices of water repellency. WRCT and RIm had less variation compared to WDPT and RIc. Estimating water repellency using WRCT and RIm indicated that these indices can detect the degree of SWR and are able to better classify SWR degree of the subcritical-repellent soil from the wettable soil.

  9. Improved method for the determination of nonpurgeable suspended organic carbon in natural water by silver filter filtration, wet chemical oxidation, and infrared spectrometry

    Science.gov (United States)

    Burkhardt, M.R.; Brenton, R.W.; Kammer, J.A.; Jha, V.K.; O'Mara-Lopez, P. G.; Woodworth, M.T.

    1999-01-01

    Precision and accuracy are reported for the first time for the analysis of nonpurgeable suspended organic carbon by silver membrane filtration followed by wet chemical oxidation. A water sample is pressure filtered through a 0.45-??m-pore-size, 47-mm-diameter silver membrane filter. The silver membrane filter then is cut into ribbons and placed in a flame-sealable glass ampule. The organic material trapped on the membrane filter strips is acidified, purged with oxygen to remove inorganic carbonates and volatile organic compounds, and oxidized to carbon dioxide (CO2) using phosphoric acid and potassium persulfate in the sealed glass ampule. The resulting CO2 is measured by a nondispersive infrared CO2 detector. The amount of CO2 is proportional to the concentration of chemically oxidizable nonpurgeable organic carbon in the environmental water sample. The quantitation and method detection limit for routine analysis is 0.2 mg/L. The average percent recovery in five representative matrices was 97 ?? 11%. The errors associated with sampling and sample preparation of nonpurgeable suspended organic carbon are also described.Precision and accuracy are reported for the first time for the analysis of nonpurgeable suspended organic carbon by silver membrane filtration followed by wet chemical oxidation. A water sample is pressure filtered through a 0.45-??m-pore-size, 47-mm-diameter silver membrane filter. The silver membrane filter then is cut into ribbons and placed in a flame-sealable glass ampule. The organic material trapped on the membrane filter strips is acidified, purged with oxygen to remove inorganic carbonates and volatile organic compounds, and oxidized to carbon dioxide (CO2) using phosphoric acid and potassium persulfate in the sealed glass ampule. The resulting CO2 is measured by a nondispersive infrared CO2 detector. The amount of CO2 is proportional to the concentration of chemically oxidizable nonpurgeable organic carbon in the environmental water sample

  10. Dentinal tubules driven wetting of dentin: Cassie-Baxter modelling

    Science.gov (United States)

    Ramos, S. M. M.; Alderete, L.; Farge, P.

    2009-10-01

    We investigate the wetting properties of dentin surfaces submitted to a phosphoric acid etching followed by an air drying procedure, as in clinical situations of adhesive dentistry. The surface topography of the etched surfaces was characterized by AFM, and the wetting properties of water on these rough and heterogeneous surfaces were studied, by contact angle measurements. We showed that the contact angle increases with the acid exposure time and consequently with both surface roughness and the organic-mineral ratio of the dentin components. From the whole results, obtained on dentin and also on synthesized hydroxyapatites samples, we inferred a water contact angle of ˜ 133° on the dentinal tubule. These experimental results may be described by the Cassie-Baxter approach, and it is suggested that small air pockets could be formed inside the dentinal tubules.

  11. Effects of wood polymers and extractives on the adsorption of wet-end chemicals and the properties of the sheet - MPKY 03

    Energy Technology Data Exchange (ETDEWEB)

    Bobacka, V.; Lindholm, J.; Nurmi, M.; Naesman, J. [Aabo Akademi, Turku (Finland). Lab. of Paper Chemistry; Holmbom, B.; Konn, J.; Sundberg, A.; Willfoer, S. [Aabo Akademi, Turku (Finland). Lab. of Forest Products Chemistry

    1998-12-31

    The effects of deposition of dissolved and colloidal substances (disco, DCS) together with fixing agents on the wet end chemistry, and the paper quality have been studied. Increased amounts of wood resin in handsheets results in lower strength properties and friction of the sheets. Addition of isolated polysaccharides together with wood resin results in higher strength properties compared, at the same resin content, to sheets without added polysaccharides. Disco substances released from TMP were adsorbed/deposited onto different fillers. It is possible to determine the distribution of aggregated wood resin in handsheets of kraft pulp by confocal laser scanning microscopy. Addition of iron salts to a TMP suspension results in a decrease in the brightness of the fibers. The adsorption of cationic starch and cationic polyacrylamide was studied as well as the flocculation of a peroxide bleached TMP and mixture of TMP and kraft pulp in the presence of retention aids and fixing agents. The fixing agent had a minor effect on the flocculation in peroxide bleached TMP, while cationic starch induced flocculation after a threshold. When added together, cationic starch induced flocculation immediately. The retention of carbohydrates in the mixture was not much influenced by the presence of fixing agents and retention aids, but the extractives were efficiently retained. Colloidal substances adsorb both cationic starch and polyacrylamide. Of the dissolved substances, pectic acids are most efficiently aggregated. (orig.)

  12. Identifying the correlation between drug/stabilizer properties and critical quality attributes (CQAs) of nanosuspension formulation prepared by wet media milling technology.

    Science.gov (United States)

    George, Maya; Ghosh, Indrajit

    2013-01-23

    Wet media milling by top down method has proved to be an effective method to prepare nanosuspension of poorly soluble drugs/APIs. Few or no attempts have been made so far to understand the feasibility of nanosuspension formulation in terms of the mechanism of stabilization as a function of drug properties. The objective of this study was to understand the effect of drug substance and stabilizer properties to form a successful nanosuspension product. From this study, logP and enthalpy were concluded to have a direct correlation on the feasibility of formation of a stable nanosuspension. The most likely candidate for media milling was a drug substance with a high enthalpy and hydrophobicity which can be stabilized either electrostatically or sterically. The least likely candidate will be one that is hydrophilic and having a very low enthalpy value. Also the choice of an ideal stabilizer/surfactant was found to be influenced by the degree of hydrophobicity of the drug itself. Finally the morphology of the starting drug was found to significantly affect the milling time required to produce submicron particles.

  13. Improvement on the microstructure stability, mechanical and wetting properties of Sn-Ag-Cu lead-free solder with the addition of rare earth elements

    Energy Technology Data Exchange (ETDEWEB)

    Yu, D.Q.; Zhao, J.; Wang, L

    2004-08-11

    Ternary lead-free solder alloys Sn-Ag-Cu were considered as the potential alternatives to lead-tin alloys comparing with other solders. In this paper, microstructure and mechanical properties of Sn-2.5Ag-0.7Cu, Sn-3.5Ag-0.7Cu, Sn-3.5Ag-0.7Cu-0.1RE, and Sn-3.5Ag-0.7Cu-0.25RE alloys were researched. Coarse {beta}-Sn grains were formed in Sn-2.5Ag-0.7Cu and Sn-3.5Ag-0.7Cu alloys and bulky Ag{sub 3}Sn intermetallics were found in Sn-3.5Ag-0.7Cu alloy. With the addition of trace rare earth (RE) elements the coarse {beta}-Sn grains were refrained, at the same time, Cu{sub 6}Sn{sub 5} and Ag{sub 3}Sn intermetallics were finer according to the adsorption affection of the active rare earth elements. Due to the fine and uniform microstructure, the tensile strength and elongation were improved. In addition, the wetting properties were also enhanced. All these results indicated that adding trace rare earth elements was an efficient way to develop new solders.

  14. ‘Breath figures’ on leaf surfaces – formation and effects of microscopic leaf wetness

    Directory of Open Access Journals (Sweden)

    Jürgen eBurkhardt

    2013-10-01

    Full Text Available ‘Microscopic leaf wetness’ means minute amounts of persistent liquid water on leaf surfaces which are invisible to the naked eye. The water is mainly maintained by transpired water vapor condensing onto the leaf surface and to attached leaf surface particles. With an estimated average thickness of less than 1 µm, microscopic leaf wetness it is about 2 orders of magnitude thinner than morning dewfall. The most important physical processes which reduce the saturation vapor pressure and promote condensation are cuticular absorption and the deliquescence of hygroscopic leaf surface particles. Deliquescent salts form highly concentrated solutions. Depending on the amount and concentration of the dissolved ions, the physicochemical properties of microscopic leaf wetness can be considerably different from those of pure water. Microscopic leaf wetness can form continuous thin layers on hydrophobic leaf surfaces and in specific cases can act similar to surfactants, enabling a strong potential influence on the foliar exchange of ions. Microscopic leaf wetness can also enhance the dissolution, the emission, and the reaction of specific atmospheric trace gases e.g. ammonia, SO2, or ozone, leading to a strong potential role for microscopic leaf wetness in plant/atmosphere interaction. Due to its difficult detection, there is little knowledge about the occurrence and the properties of microscopic leaf wetness. However, based on the existing evidence and on physicochemical reasoning it can be hypothesized that microscopic leaf wetness occurs on almost any plant worldwide and often permanently, and that it significantly influences the exchange processes of the leaf surface with its neighboring compartments, i.e., the plant interior and the atmosphere. The omission of microscopic water in general leaf wetness concepts has caused far-reaching, misleading conclusions in the past.

  15. Thermodynamic properties of bulk and confined water

    Energy Technology Data Exchange (ETDEWEB)

    Mallamace, Francesco, E-mail: francesco.mallamace@unime.it [Dipartimento di Fisica e Scienza della Terra Università di Messina and CNISM, I-98168 Messina (Italy); Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215 (United States); Corsaro, Carmelo [Dipartimento di Fisica e Scienza della Terra Università di Messina and CNISM, I-98168 Messina (Italy); Mallamace, Domenico [Dipartimento di Scienze dell' Ambiente, della Sicurezza, del Territorio, degli Alimenti e della Salute, Università di Messina, I-98166 Messina (Italy); Vasi, Sebastiano; Vasi, Cirino [IPCF-CNR, I-98166 Messina (Italy); Stanley, H. Eugene [Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215 (United States)

    2014-11-14

    The thermodynamic response functions of water display anomalous behaviors. We study these anomalous behaviors in bulk and confined water. We use nuclear magnetic resonance (NMR) to examine the configurational specific heat and the transport parameters in both the thermal stable and the metastable supercooled phases. The data we obtain suggest that there is a behavior common to both phases: that the dynamics of water exhibit two singular temperatures belonging to the supercooled and the stable phase, respectively. One is the dynamic fragile-to-strong crossover temperature (T{sub L} ≃ 225 K). The second, T{sup *} ∼ 315 ± 5 K, is a special locus of the isothermal compressibility K{sub T}(T, P) and the thermal expansion coefficient α{sub P}(T, P) in the P–T plane. In the case of water confined inside a protein, we observe that these two temperatures mark, respectively, the onset of protein flexibility from its low temperature glass state (T{sub L}) and the onset of the unfolding process (T{sup *})

  16. Influence of n-hexanol and n-octanol on wetting properties and air entrapment at superhydrophobic surfaces.

    Science.gov (United States)

    Krasowska, Marta; Ferrari, Michele; Liggieri, Libero; Malysa, Kazimierz

    2011-05-28

    Superhydrophobic surfaces have recently attracted a lot of attention due to their self-cleaning properties. The superhydrophobic surfaces used in our studies were prepared using a mixed inorganic-organic coating. In order to check how short chain surface active agents affect the surface energy of such surfaces, their wettability (sessile drop technique) and the kinetics of the three phase contact formation were studied. It was found that with increasing concentrations of n-hexanol and n-octanol the surface energy of these surfaces was only slightly changed, i.e. a small decrease in contact angle values with increasing solution concentration was detected. Even for the most concentrated n-hexanol and n-octanol solutions, the contact angles were in the range 145-155° and the drop rolled off, indicating that the studied surfaces stayed superhydrophobic. Air bubbles, upon collision with such superhydrophobic surfaces, spread over the superhydrophobic surface within milliseconds in the studied solutions.

  17. 汽轮机内湿蒸汽两相流介电性质研究%Study on Dielectric Properties of Wet Steam in Turbine

    Institute of Scientific and Technical Information of China (English)

    钱江波; 韩中合; 张美凤

    2011-01-01

    The relationship between complex permittivity and static dielectric parameters,frequency of alternating electric field was substituted into the Maxwell-Wagner non-homogeneous dielectric theory.An equivalent complex permittivity model of wet steam was established.The complex permittivity distribution of saturated water,dry saturated steam and wet steam with wavelength and temperature changing were obtained.The real part of saturated water complex permittivity increases with wavelength increasing and temperature decreasing.When wavelength is large,the real part closes to static dielectric constant,and when wavelength is small,it closes to a constant,independent of temperature.The imaginary part of saturated water complex permittivity first increases and then decreases with wavelength increasing,and it increases with temperature decreasing.When wavelength is large or small,the imaginary part closes to 0.The real part of dry saturated steam complex permittivity increases with wavelength and temperature increasing.When wavelength is small or temperature is low,the real part closes to 1.The imaginary part of dry saturated steam complex permittivity first increases and then decreases with wavelength increasing,and it increases with temperature increasing.When wavelength is large or small or temperature is low,the imaginary part closes to 0.The complex permittivity of wet steam is similar to the one of dry saturated steam.When humidity increases especially in high temperature,the real and imaginary parts are larger.%将电介质的复介电常数与其静介电参数、交变电场频率的关系引入Maxwell-Wagner非均质电介质理论,建立湿蒸汽等效复介电常数模型,得到饱和水、干饱和蒸汽和湿蒸汽的复介电常数随波长和温度的变化。饱和水复介电常数的实部随波长增加、温度降低而变大,当波长较大时,实部趋于静介电常数,当波长较小时,实部趋于常数,与温度无关;其虚部随波长增加先

  18. Adhesion and Water Repellent Properties Of Nascent Dammar—Silicone Thin Film: A Bio Mimicry Approach

    Science.gov (United States)

    Zakaria, R.; Ahmad, A. H.

    2009-06-01

    Dammar, a local plant resin (Dipterocaupacea sp) has been used in coating formulation to produce dammar-modified silicone resin. Dammar and silicone were mixed in various compositions and then were coated onto Aluminum Q-panel by using spin coating method and left to dry at room temperature. Adhesion property was investigated by using impact test and pull-off test. There were no significant damage and delaminations were observed at the panel coated with 15 wt.% of dammar that has undergone the impact test. Hence, the addition of more than 15 wt.% of dammar resulted in large delaminations and cracks on the coating materials. Results from pull off test also showed that 15 wt.% of dammar organic coating has strong adhesion, 108 Psi. It made 15 wt% as optimized composition. This optimized composition was added with nanopowder as rheological modifier or additive. Again the modified samples were undergone the impact and pull off test to study the effect of adhesiveness. Contact angle measurement of wettability test was also being carried out. The surface coated with dammar-silicone resin was found to be hydrophobic where the contact angle obtained was 70° for the sample containing 10 wt% of dammar. The additional of nanopowder into optimized composition exhibited more hydrophobic phenomenon which approached towards bio-mimicry behaviour, when water droplets simply rest on the surface without actually wetting the surface to any significant extent (hydrophobic) where the angle of wetting tests more than 90° have been achieved.

  19. Water-soluble cavitands - synthesis, solubilities and binding properties

    NARCIS (Netherlands)

    Middel, Oskar; Verboom, Willem; Reinhoudt, David N.

    2002-01-01

    Water-soluble cavitand receptors have been obtained by the introduction of ionizable groups (5, 21-28, 39) and neutral hydrophilic tetraethylene glycol based dendritic wedges (19, 20). The synthesis of these cavitands and a study of their water solubilities and binding properties toward neutral orga

  20. Thermodynamic properties of water desorption of forage turnip seeds

    OpenAIRE

    Kelly Aparecida Sousa; Osvaldo Resende; André Luis Duarte Goneli; Thaís Adriana de Souza Smaniotto; Daniel Emanuel Cabral de Oliveira

    2014-01-01

    The purpose of this study was to determine the thermodynamic properties of the process of water sorption in forage turnip  seeds. The equilibrium moisture content of forage turnip  seeds was determined by the gravimetric-dynamic method for different values of temperature and water activity. According to the results, increasing the moisture content increases the energy required for the evaporation of water in forage turnip seeds, and the values of integral isosteric heat of desorption, within ...

  1. Thermodynamic properties of water desorption of forage turnip seeds

    OpenAIRE

    Sousa,Kelly Aparecida de; Resende,Osvaldo; Goneli, André Luis Duarte; Smaniotto,Thaís Adriana de Souza; Oliveira,Daniel Emanuel Cabral de

    2015-01-01

    The purpose of this study was to determine the thermodynamic properties of the process of water sorption in forage turnip seeds. The equilibrium moisture content of forage turnip seeds was determined by the gravimetric-dynamic method for different values of temperature and water activity. According to the results, increasing the moisture content increases the energy required for the evaporation of water in forage turnip seeds, and the values of integral isosteric heat of desorption, within th...

  2. THERMOPHYSICAL PROPERTIES AND WATER ACTIVITY OF TRANSFERRED CHEESE (UF

    Directory of Open Access Journals (Sweden)

    Mohsen Dalvi Esfahan

    2015-06-01

    Full Text Available Few data are available on the thermophysical properties of cheese in the ripening process.The main objective of this work was to investigate the effects of brining and temperature on the thermophysical properties, i.e., thermal conductivity, specific heat, density and water activity of UF cheese and finally we measure surface heat transfer coefficient .Then we develop models for thermophysical properties based on physical and multiple regression concept .

  3. Particles in water properties and processes

    CERN Document Server

    Gregory, John

    2005-01-01

    INTRODUCTION Particles in the Aquatic Environment Colloidal Aspects PARTICLE SIZE AND RELATED PROPERTIES Particle Size and Shape Particle Size Distributions Particle Transport Light Scattering and Turbidity Measurement of Particle Size SURFACE CHARGE Origin of Surface Charge The Electrical Double Layer Electrokinetic Phenomena COLLOID INTERACTIONS AND COLLOID STABILITY Colloid Interactions - General Concepts van der Waals Interaction Electrical Double Layer Interaction Combined Interaction - DLVO Theory Non-DLVO Interactions AGGREGATION KINETICS Collision Frequency - Smoluchow

  4. An intercalibrated dataset of total column water vapour and wet tropospheric correction based on MWR on board ERS-1, ERS-2, and Envisat

    Science.gov (United States)

    Bennartz, Ralf; Höschen, Heidrun; Picard, Bruno; Schröder, Marc; Stengel, Martin; Sus, Oliver; Bojkov, Bojan; Casadio, Stefano; Diedrich, Hannes; Eliasson, Salomon; Fell, Frank; Fischer, Jürgen; Hollmann, Rainer; Preusker, Rene; Willén, Ulrika

    2017-04-01

    The microwave radiometers (MWRs) on board the European Remote Sensing Satellites 1 and 2 (ERS-1 and ERS-2) and Envisat provide a continuous time series of brightness temperature observations between 1991 and 2012. Here we report on a new total column water vapour (TCWV) and wet tropospheric correction (WTC) dataset that builds on this time series. We use a one-dimensional variational approach to derive TCWV from MWR observations and ERA-Interim background information. A particular focus of this study lies on the intercalibration of the three different instruments, which is performed using constraints on liquid water path (LWP) and TCWV. Comparing our MWR-derived time series of TCWV against TCWV derived from Global Navigation Satellite System (GNSS) we find that the MWR-derived TCWV time series is stable over time. However, observations potentially affected by precipitation show a degraded performance compared to precipitation-free observations in terms of the accuracy of retrieved TCWV. An analysis of WTC shows further that the retrieved WTC is superior to purely ERA-Interim-derived WTC for all satellites and for the entire time series. Even compared to the European Space Agency's (ESA) operational WTC retrievals, which incorporate in addition to MWR additional observational data, the here-described dataset shows improvements in particular for the mid-latitudes and for the two earlier satellites, ERS-1 and ERS-2. The dataset is publicly available under doi:10.5676/DWD_EMIR/V001 (Bennartz et al., 2016).

  5. Study on Wet Permeability Models of Yarns and Knitted Fabrics

    Institute of Scientific and Technical Information of China (English)

    王其; 冯勋伟

    2001-01-01

    Water transport through the pore structure of the knitted fabric can occur only in place where the fiber-water surface attraction force is greater than the water weight in the capillary. To investigate wet permeability of the knitted yarn in the fabric, a liquid transport model is established. The main factors which have significant influences on the liquid transport have been analyzed. It is derived from the argument that the optimal design for the knitted fabric with quick sweat transport property can be obtained.

  6. Designer-Wet Micromodels for Studying Potential Changes in Wettability during Microbial Enhanced Oil Recovery

    Science.gov (United States)

    Armstrong, R. T.; Wildenschild, D.

    2010-12-01

    Microbial Enhanced Oil Recovery (MEOR) is a process where microorganisms are used for tertiary recovery of oil. Some bacteria can facilitate the mobilization of oil through the production of amphiphilic compounds called biosurfactants that reduce the interfacial tension (IFT) between immiscible phases. Additionally, most bacteria have an inclination to colonize surfaces and form biofilm, which can change a reservoir's wetting properties or clog preferential flow paths. Herein, we aim to understand changes in wettability during MEOR under mixed wettability conditions within silicon etched micromodels and to identify the type of oil field (i.e. based on wettability) in which MEOR is likely to be most profitable. To quantify porous media wettability, macro-scale indexes (obtained with techniques such as the Carter or Amott methods) are used regularly. However, these measurements lack the capability for characterization of changes in wettability during MEOR treatment, and only provide macro-scale information. In an effort to understand micro-scale temporal and spatial changes in wettability we measure interfacial curvature from stereo microscope images using level set methods. Curvature, from the perspective of the oil phase, is positive for a concave interface (i.e. water-wet surface) and negative for a convex interface (i.e. oil-wet surface). Thus, shifts in the radius of curvature distribution (i.e. from positive to negative or conversely) are indicative of wettability changes. Both curvature distributions using level-set methods and the Carter method are used to characterize wettability before and after microbial treatment. In preliminary studies aimed at understanding wettability changes due to microbial surface interactions by Bacillus mojavensis JF-2, oil droplets were placed on glass slides suspended in growth media and the resulting contact angle was measured over time. Results showed that a water-wet surface will become more water wet as JF-2 accumulated in

  7. Industrially benign super-compressible piezoresistive carbon foams with predefined wetting properties: from environmental to electrical applications

    Science.gov (United States)

    Pham, Tung Ngoc; Samikannu, Ajaikumar; Kukkola, Jarmo; Rautio, Anne-Riikka; Pitkänen, Olli; Dombovari, Aron; Lorite, Gabriela Simone; Sipola, Teemu; Toth, Geza; Mohl, Melinda; Mikkola, Jyri-Pekka; Kordas, Krisztian

    2014-11-01

    In the present work electrically conductive, flexible, lightweight carbon sponge materials derived from open-pore structure melamine foams are studied and explored. Hydrophobic and hydrophilic surface properties - depending on the chosen treatment conditions - allow the separation and storage of liquid chemical compounds. Activation of the carbonaceous structures substantially increases the specific surface area from ~4 m2g-1 to ~345 m2g-1, while retaining the original three-dimensional, open-pore structure suitable for hosting, for example, Ni catalyst nanoparticles. In turn the structure is rendered suitable for hydrogenating acetone to 2-propanol and methyl isobutyl ketone as well for growing hierarchical carbon nanotube structures used as electric double-layer capacitor electrodes with specific capacitance of ~40 F/g. Mechanical stress-strain analysis indicates the materials are super-compressible (>70% volume reduction) and viscoelastic with excellent damping behavior (loss of 0.69 +/- 0.07), while piezoresistive measurements show very high gauge factors (from ~20 to 50) over a large range of deformations. The cost-effective, robust and scalable synthesis - in conjunction with their fascinating multifunctional utility - makes the demonstrated carbon foams remarkable competitors with other three-dimensional carbon materials typically based on pyrolyzed biopolymers or on covalently bonded graphene and carbon nanotube frameworks.

  8. Microstructures and Mechanical Properties of Friction Tapered Stud Overlap Welding for X65 Pipeline Steel Under Wet Conditions

    Science.gov (United States)

    Xu, Y. C.; Jing, H. Y.; Han, Y. D.; Xu, L. Y.

    2017-08-01

    This paper exhibits a novel in situ remediation technique named friction tapered stud overlap welding (FTSOW) to repair a through crack in structures and components in extremely harsh environments. Furthermore, this paper presents variations in process data, including rotational speed, stud displacement, welding force, and torque for a typical FTSOW weld. In the present study, the effects of welding parameters on the microstructures and mechanical properties of the welding joints were investigated. Inapposite welding parameters consisted of low rotational speeds and welding forces, and when utilized, they increased the occurrence of a lack of bonding and unfilled defects within the weld. The microstructures with a welding zone and heat-affected zone mainly consisted of upper bainite. The hardness value was highest in the welding zone and lowest in the base material. During the pull-out tests, all the welds failed in the stud. Moreover, the defect-free welds broke at the interface of the lap plate and substrate during the cruciform uniaxial tensile test. The best tensile test results at different depths and shear tests were 721.6 MPa and 581.9 MPa, respectively. The favorable Charpy impact-absorbed energy was 68.64 J at 0 °C. The Charpy impact tests revealed a brittle fracture characteristic with a large area of cleavage.

  9. Handling of wet residues in industry

    DEFF Research Database (Denmark)

    Villanueva, Alejandro

    In countries with high prices of fresh water use and wastewater discharge, water recycling has become an alternative to traditional water consumption and discharge for industries with water-based processes. Industrial water recycling means in many cases that water has to be treated and cleaned......, to remove from it the substances which presence impedes reusing the water. These substances accumulate in a by-product called wet residue. An integral part of water recycling projects in the industry is the handling and disposal of the wet residues generated. The treatment, utilisation and disposal of wet...... residues depend totally on the industrial sector of origin and the composition of the water to be recycled. Treatment is more problematic in some cases than in others, but in all water recycling applications it is an issue of concern. The present study addresses this concern by providing a package...

  10. Intensive measurements of gas, water, and energy exchange between vegetation and troposphere during the MONTES Campaign in a vegetation gradient from short semi-desertic shrublands to tall wet temperate forests in the NW Mediterranean basin

    Science.gov (United States)

    MONTES (“Woodlands”) was a multidisciplinary international field campaign aimed at measuring energy, water and especially gas exchange between vegetation and atmosphere in a gradient from short semi-desertic shrublands to tall wet temperate forests in NE Spain in the North Wester...

  11. Influence of physical and chemical polymer-filler bonds on wet skid resistance and related properties of passenger car tire treads

    NARCIS (Netherlands)

    Cichomski, E.M.; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.; Tolpekina, T.V.; Schultz, S.M.

    2012-01-01

    Knowledge about the influence of rubber – filler interactions on the wet skid behavior of tire treads is insufficient, in order to quickly develop new compounds with improved wet skid performance. The rubber compound used for a tire tread is in fact a composite material of which the dynamic

  12. 水质对染整加工的影响(一)%Impacts of water quality on wet processing (Ⅰ)

    Institute of Scientific and Technical Information of China (English)

    曹万里; 吕志阳; 顾志安

    2012-01-01

    阐述印染用水各项水质指标对染整加工的影响,包括pH值、浊度、色度、硬度、重金属离子、活性氯与氯离子、COD、BOD、电导率、固体悬浮物(SS)、总碱度和总固体等,分析了它们的来源、作用机理和解决方法.%Effects of a variety of water quality indexes on dyeing and finishing processes are introduced,including pH value, turbidity, colourity, hardness, heavy metallic ion, active chlorine and chloride ion, COD and BOD, electrical conductivity, SS(solid suspension), total alkalinity and total solids. The sources, mechanism and solutions are analyzed.

  13. Pretreatment of refinery waste water by wet oxidation. LOPROX {sup registered} procedure: Alternative treatment of sulfidic waste lyes by wet oxidation; Vorbehandlung von Raffinerieabwasser durch Nassoxidation. LOPROX {sup registered} -Verfahren: Alternative Behandlung von sulfidischen Ablaugen durch Nassoxidation

    Energy Technology Data Exchange (ETDEWEB)

    Leonhaeuser, Johannes; Weissenberg, Dirk; Birkenbeul, Udo [Bayer Technology Services GmbH (BTS), Leverkusen (Germany). Technology Development and Engineering; Bloecher, Christoph [Currenta (Germany)

    2012-05-15

    The authors of the contribution under consideration report on the treatment of refinery wastewater by means of the wet oxidation. The authors present the LOPROX {sup registered} method as an alternative treatment of sulfidic waste lyes. This method can not only treat successfully organic polluted wastewater from the chemical industry, but also various waste lyes from refinery processes. Based on a customer-specific process optimization in pilot scale, a cost-effective treatment can be achieved.

  14. Dielectric Properties of Water in Butter and Water-AOT-Heptane Systems Measured using Terahertz Time-Domain Spectroscopy

    DEFF Research Database (Denmark)

    Møller, Uffe; Folkenberg, Jacob Riis; Jepsen, Peter Uhd

    2010-01-01

    We investigate the dielectric properties of water confined in nanometer-sized inverse micelles in mixtures of water, AOT, and heptane. We show that the dielectric properties of the confined water are dependent on the water pool size and different from those of bulk water. We also discuss the diel...... the dielectric properties of different vegetable oils, lard, and butter, and use these properties to deduce the dielectric properties of water in butter, which are shown to deviate significantly from the dielectric properties of bulk water....

  15. Viscosity and electric properties of water aerosols

    Science.gov (United States)

    Shavlov, A. V.; Sokolov, I. V.; Dzhumandzhi, V. A.

    2016-09-01

    The flow of water mist in a narrow duct has been studied experimentally. The profile of the velocity of drops has been measured, and the viscosity of the mist has been calculated using the Navier-Stokes equation. It has been found that at low gradients of the rate of shear the viscosity of the mist can exceed that of clean air by tens and even hundreds of times. The electric charge of the drops has been measured. It has been found that the viscosity of the mist differs from that of clean air at gradients of the rate of shear that are less than the frequency of the establishment of electric equilibrium between the drops. A comparative analysis of the viscosities of the mist and a drop cluster has been carried out, and the dependence of the viscosity of the water aerosol on the radius and the charge of the drops has been predicted. The possible role of aerosols that contain submicron drops in the known "clear air turbulence" problem has been shown.

  16. Effect of Synthesis Parameters on the Structure and Magnetic Properties of Magnetic Manganese Ferrite/Silver Composite Nanoparticles Synthesized by Wet Chemistry Method

    DEFF Research Database (Denmark)

    Huy, L.T.; Tam, L.T.; Phan, V.N.

    2016-01-01

    In the present work, magnetic manganese ferrite/silver (MnFe2O4-Ag) composite nanoparticles were synthesized by wet chemistry method. This synthesis process consists of two steps: first, the seed of manganese ferrite nanoparticles (MnFe2O4 NPs) was prepared by a coprecipitationmethod; second......, growth of silver nanoparticles (AgNPs) on the MnFe2O4 seed by modified photochemical reaction. We have conducted systematically the effects of synthesis parameters such as pH value, synthesis time, precursor salts concentration, mass ratio and stabilizing agents on the structure and magnetic properties...... of nanocomposites. In an optimized condition of synthesis parameters, the high quality MnFe2O4 NPs are obtained at pH value = 13, Mn2+ cation concentration= 0.4 M and synthesis time about 105 min; and the use of PVP stabilizing agent is found to optimize the formation of Ag-NPs on the surface of MnFe2O4 NPs. The as...

  17. Wetting in Color

    Science.gov (United States)

    Burgess, Ian Bruce

    Colorimetric litmus tests such as pH paper have enjoyed wide commercial success due to their inexpensive production and exceptional ease of use. However, expansion of colorimetry to new sensing paradigms is challenging because macroscopic color changes are seldom coupled to arbitrary differences in the physical/chemical properties of a system. In this thesis I present in detail the development of Wetting in Color Technology, focusing primarily on its application as an inexpensive and highly selective colorimetric indicator for organic liquids. The technology exploits chemically-encoded inverse-opal photonic crystals to control the infiltration of fluids to liquid-specific spatial patterns, projecting minute differences in liquids' wettability to macroscopically distinct, easy-to-visualize structural color patterns. It is shown experimentally and corroborated with theoretical modeling using percolation theory that the high selectivity of wetting, upon-which the sensitivity of the indicator relies, is caused by the highly symmetric structure of our large-area, defect-free SiO2 inverse-opals. The regular structure also produces a bright iridescent color, which disappears when infiltrated with liquid - naturally coupling the optical and fluidic responses. Surface modification protocols are developed, requiring only silanization and selective oxidation, to facilitate the deterministic design of an indicator that differentiates a broad range of liquids. The resulting tunable, built-in horizontal and vertical chemistry gradients allow the wettability threshold to be tailored to specific liquids across a continuous range, and make the readout rely only on countable color differences. As wetting is a generic fluidic phenomenon, Wetting in Color technology could be suitable for applications in authentication or identification of unknown liquids across a broad range of industries. However, the generic nature of the response also ensures chemical non-specificity. It is shown

  18. Modeled Wet Nitrate Deposition

    Data.gov (United States)

    U.S. Environmental Protection Agency — Modeled data on nitrate wet deposition was obtained from Dr. Jeff Grimm at Penn State Univ. Nitrate wet depostion causes acidification and eutrophication of surface...

  19. Vaginitis test - wet mount

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003916.htm Vaginitis test - wet mount To use the sharing features on this page, please enable JavaScript. The vaginitis wet mount test is a test to detect ...

  20. Novel wireless health monitor with acupuncture bio-potentials obtained by using a replaceable salt-water-wetted foam-rubber cushions on RFID-tag.

    Science.gov (United States)

    Lin, Jium-Ming; Lu, Hung-Han; Lin, Cheng-Hung

    2014-01-01

    This paper proposes a bio-potential measurement apparatus including a wireless device for transmitting acupuncture bio-potential information to a remote control station for health conditions analysis and monitor. The key technology of this system is to make replaceable foam-rubber cushions, double-side conducting tapes, chip and antenna on the radio frequency identification (RFID) tag. The foam-rubber cushions can be wetted with salt-water and contact with the acupuncture points to reduce contact resistance. Besides, the double-side conducting tapes are applied to fix foam-rubber cushions. Thus, one can peel the used cushions or tapes away and supply new ones quickly. Since the tag is a flexible plastic substrate, it is easy to deploy on the skin. Besides, the amplifier made by CMOS technology on RFID chip could amplify the signals to improve S/N ratio and impedance matching. Thus, cloud server can wirelessly monitor the health conditions. An example shows that the proposed system can be used as a wireless health condition monitor, the numerical method and the criteria are given to analyze eleven bio-potentials for the important acupunctures of eleven meridians on a person's hands and legs. Then a professional doctor can know the performance of an individual and the cross-linking effects of the organs.

  1. Dry? or Wet? Magma-Water Interaction during Minoan-Thera Eruption of Santorini depicted from 3D morphological analysis of Ashes

    Science.gov (United States)

    Aydar, E.; Ecochard, E.; Çiner, A.; Fouache, E.

    2012-04-01

    Powerful and, catastrophic Minoan-Thera eruption of Santorini occurred at mid-second millennium BC (~3300 BP) produced totally 30 km3 DRE of tephras (Sigurdsson et al., 1990; Pyle, 1990). Magnitude of Minoan-Thera of Santorini Late Bronze Age eruption was estimated as 6 (Colossal) to 7(super colossal) corresponding to Plinian/Ultraplinian style activity according to Volcanic Explosivity Index (McCoy&Heiken,2000). During this one of the largest eruptions in the human history, vent properties and eruption dynamics have changed from dry plinian phase (first phase) to wet phreatomagmatic surges and to pyroclastic flows, comprising of four distinct phases. Convective eruption cloud formed in the first phase was under influence of westerly winds, according to numerous published papers, extending toward east-northeast-southeast, toward Black Sea, Turkey, Mediterannean Sea. We drilled Letoon Plain, southwestern coast of Turkey and cut 3 cm thick tephra deposit overlying an organic material-rich layer dated as 1612 BC (C14, AMS method), corresponding well to the age of Minoan-Thera eruption. The iron content of Minoan-Thera tephras (≥ 2%) is higher than Turkish tephras (in general 2 as polyhedron - multifractal unvesiculated glassy ashes. Meanwhile, blocky-equant ashes have SA/PA nature of the first phase of Minoan-Thera is not purely magmatic as it was classically claimed in most of the previous works.

  2. Analytic model for the electrowetting properties of oil-water-solid systems

    NARCIS (Netherlands)

    Cavalli, Andrea; Bera, B.; van den Ende, Henricus T.M.; Mugele, Friedrich Gunther

    2016-01-01

    The competitive wetting of oil and aqueous electrolytes on solid surfaces depends strongly on the surface charge of the solid-water and the water-oil interface. This charge density is generally not known a priori but changes as ions adsorb or desorb from or to the interfaces, depending on the

  3. Membranes with Surface-Enhanced Antifouling Properties for Water Purification

    Science.gov (United States)

    Shahkaramipour, Nima; Tran, Thien N.; Ramanan, Sankara; Lin, Haiqing

    2017-01-01

    Membrane technology has emerged as an attractive approach for water purification, while mitigation of fouling is key to lower membrane operating costs. This article reviews various materials with antifouling properties that can be coated or grafted onto the membrane surface to improve the antifouling properties of the membranes and thus, retain high water permeance. These materials can be separated into three categories, hydrophilic materials, such as poly(ethylene glycol), polydopamine and zwitterions, hydrophobic materials, such as fluoropolymers, and amphiphilic materials. The states of water in these materials and the mechanisms for the antifouling properties are discussed. The corresponding approaches to coat or graft these materials on the membrane surface are reviewed, and the materials with promising performance are highlighted. PMID:28273869

  4. Membranes with Surface-Enhanced Antifouling Properties for Water Purification

    Directory of Open Access Journals (Sweden)

    Nima Shahkaramipour

    2017-03-01

    Full Text Available Membrane technology has emerged as an attractive approach for water purification, while mitigation of fouling is key to lower membrane operating costs. This article reviews various materials with antifouling properties that can be coated or grafted onto the membrane surface to improve the antifouling properties of the membranes and thus, retain high water permeance. These materials can be separated into three categories, hydrophilic materials, such as poly(ethylene glycol, polydopamine and zwitterions, hydrophobic materials, such as fluoropolymers, and amphiphilic materials. The states of water in these materials and the mechanisms for the antifouling properties are discussed. The corresponding approaches to coat or graft these materials on the membrane surface are reviewed, and the materials with promising performance are highlighted.

  5. Wet solids flow enhancemant

    Energy Technology Data Exchange (ETDEWEB)

    Caram, H.S.; Foster, N.; Wildman, D.J. [USDOE Pittsburgh Energy Technology Center, PA (United States)

    1996-12-31

    WE used glass beads of different sizes as.a model system to study the flow enhancing properties of Octadecyltrichlorosilane (OTS). 0TS provides Si(CH{sub 2}){sub 17}CH{sub 3} groups that bind with the surface hydrox groups to make it hydrophobic. Experimental data showed, indeed, that surface hydrophobicity promotes the flow of wet granular materials. Mixtures of different percentage of silanized/unsilanized particles were prepared for tensile strength measurements. The tensile strength decreased as more silanized particles were added to the samples. The relationship between dimensionless tensile strength and void fraction followed the correlation found by Pierrat (1994). Contact angles were larger for the silanized particles, as compared with unsilanized ones.

  6. An Inactive Water-Wet Film for Paraffin Inhibition in Qinghai Oilfield%青海油田亲水钝化膜防蜡技术研究

    Institute of Scientific and Technical Information of China (English)

    窦红梅; 王龙飞

    2013-01-01

    Paraffin precipitation is seriously affecting crude oil production in Qinghai Oilfield .In order to solve the increasingly worsening problem of paraffin precipitation and achieve the goal of high and stable yields at low cost ,this paper comprehensively analyzed the application status of paraffin inhibition technol-ogies in Qinghai Oilfield on the basis of investigation ,and proposed a new paraffin inhibition method ,name-ly water-wet inactive film technology .A new chemical is added into tubing to form a water-wet inactive film on tubing surface to inhibit paraffin ,corrosion and scale precipitation .Through theoretical analysis and la-boratory infrared spectroscopy experiment ,the paraffin inhibition mechanism of the new technique was show n in detail from the microscopic view ,that is the hydrophilic groups of the inactive film strongly inter-act with water through hydrogen bonds to form a stable chelate ,preventing paraffin deposition .Laboratory experiment and field application show that the new technology works better than traditional chemical par-affin inhibition methods ,especially for oil wells with 30% 50% water cut ,it can effectively control paraf-fin ,slow corrosion ,prevent scale formation ,extend purge period and pump inspection interval ,raise produc-tion ,w hich show s good economic benefits and promising prospects of application .%青海油田油井结蜡现象严重,结蜡问题已经成为影响该油田正常生产的重要因素。为了有效解决该问题,实现稳产、增产并降低生产成本,对青海油田清蜡防蜡技术应用现状进行了综合分析,提出了亲水钝化膜防蜡技术。该技术通过加入油管表面处理剂,使其与油管表面反应生成亲水钝化膜,达到防蜡、防腐、防垢的目的。通过理论分析和室内红外光谱试验,从微观角度详细阐述了该技术的防蜡机理:亲水钝化膜中的基团与水发生强氢键作用形成稳定螯合物,从而抑制蜡

  7. Effect of coagulation temperature on structures and properties of poly(p-phenylene benzobisoxazole) (DHPBO) fibers during dry-jet wet-spinning process

    Institute of Scientific and Technical Information of China (English)

    ZHANG Tao; JIN JunHong; HU DaYong; YANG ShengLin; LI Guang; JIANG JianMing

    2009-01-01

    The effect of coagulation temperature on the morphology, microstructures and mechanical properties of dihydroxy poly(p-phenylene benzobisoxazole) (DHPBO) fibers was investigated during dry-jet wetspinning process, in which the coagulation bath concentration and drawn ratio were kept as 10 wt% of PPA in water and 1.7, respectively. The structures and mechanical properties of the as-spun DHPBO fibers were characterized by FTIR, XRD, SEM, and single fiber tensile testing. The results indicated that in PPA/H20 coagulation system, when the coagulation temperature was 25℃, highly crystallized DHPBO as-spun fibers possessing fine crystallites, circular and smooth morphology, and excellent mechanical properties could be achieved.

  8. Dielectric properties of low-water-content tissues.

    Science.gov (United States)

    Smith, S R; Foster, K R

    1985-09-01

    The dielectric properties of two low-water-content tissues, bone marrow and adipose tissue, were measured from 1 kHz to 1 GHz. From 1 kHz to 13 MHz, the measurements were performed using a parallel-plate capacitor method. From 10 MHz to 1 GHz, a reflection coefficient technique using an open-ended coaxial transmission line was employed. The tissue water contents ranged from 1 to almost 70% by weight. The dielectric properties correlate well with the values predicted by mixture theory. Comparison with previous results from high-water-content tissues suggests that bone marrow and adipose tissues contain less motionally altered water per unit dry volume than do the previously studied tissues with lower lipid fractions. The high degree of structural heterogeneity of these tissues was reflected in the large scatter of the data, a source of uncertainty that should be considered in practical applications of the present data.

  9. Thermodynamic properties and diffusion of water + methane binary mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Shvab, I.; Sadus, Richard J., E-mail: rsadus@swin.edu.au [Centre for Molecular Simulation, Swinburne University of Technology, PO Box 218 Hawthorn, Victoria 3122 (Australia)

    2014-03-14

    Thermodynamic and diffusion properties of water + methane mixtures in a single liquid phase are studied using NVT molecular dynamics. An extensive comparison is reported for the thermal pressure coefficient, compressibilities, expansion coefficients, heat capacities, Joule-Thomson coefficient, zero frequency speed of sound, and diffusion coefficient at methane concentrations up to 15% in the temperature range of 298–650 K. The simulations reveal a complex concentration dependence of the thermodynamic properties of water + methane mixtures. The compressibilities, heat capacities, and diffusion coefficients decrease with increasing methane concentration, whereas values of the thermal expansion coefficients and speed of sound increase. Increasing methane concentration considerably retards the self-diffusion of both water and methane in the mixture. These effects are caused by changes in hydrogen bond network, solvation shell structure, and dynamics of water molecules induced by the solvation of methane at constant volume conditions.

  10. Wet inside and out? Constraints on water in the Martian mantle and on outgassed water, based on melt inclusions in SNC meteorites

    Science.gov (United States)

    Mcsween, H. Y., Jr.; Harvey, R. P.

    1993-01-01

    Constraints on the volatile inventory and outgassing history of Mars are critical to understanding the origin of ancient valley systems and paleoclimates. Planetary accretion models for Mars allow either a volatile-rich or volatile-poor mantle, depending on whether the accreted materials were fully oxidized or whether accretion was homogeneous so that water was lost through reaction with metallic iron. The amount of water that has been outgassed from the interior is likewise a contentious subject, and estimates of globally distributed water based on various geochemical and geological measurements vary from a few meters to more than a thousand meters. New data on SNC meteorites, which are thought to be Martian igneous rocks, provide constraints on both mantle and outgassed water.

  11. Locomotion and drag in wet and dry granular media

    Science.gov (United States)

    Goldman, Daniel; Kuckuk, Robyn; Sharpe, Sarah

    2015-03-01

    Many animals move within substrates such as soil and dry sand; the resistive properties of such granular materials (GM) can depend on water content and compaction, but little is known about how such parameters affect locomotion or the relevant physics of drag and penetration. We developed a system to create homogeneous wet GM of varying moisture content and compaction in quantities sufficient to study the burial and subsurface locomotion of the Ocellated skink (C. ocellatus) a desert-generalist lizard. X-ray imaging revealed that in wet and dry GM the lizard slowly buried (~ 30 seconds) propagating a wave from head to tail, while moving in a start-stop motion. During forward movement, the head oscillated, and the forelimb on the convex side of the body propelled the animal. Although body kinematics (and ``slip'') were similar in both substrates, the burial depth was smaller in wet GM. Penetration and drag force experiments on smooth cylinders revealed that wet GM was ~ 3 × more resistive than dry GM, suggesting that during burial the lizard operated near its maximum force producing capability and was thus constrained by environmental properties. work supported by NSF PoLS.

  12. Properties of water surface discharge at different pulse repetition rates

    Energy Technology Data Exchange (ETDEWEB)

    Ruma,; Yoshihara, K. [Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555 (Japan); Hosseini, S. H. R., E-mail: hosseini@kumamoto-u.ac.jp; Sakugawa, T.; Akiyama, H. [Graduate School of Science and Technology, Kumamoto University, Kumamoto 860-8555 (Japan); Institute of Pulsed Power Science, Kumamoto University, Kumamoto 860-8555 (Japan); Akiyama, M. [Department of Electrical and Electronic Engineering, Kagoshima University, Kagoshima 890-0065 (Japan); Lukeš, P. [Institute of Plasma Physics, AS CR, Prague, Prague 18200 (Czech Republic)

    2014-09-28

    The properties of water surface discharge plasma for variety of pulse repetition rates are investigated. A magnetic pulse compression (MPC) pulsed power modulator able to deliver pulse repetition rates up to 1000 Hz, with 0.5 J per pulse energy output at 25 kV, was used as the pulsed power source. Positive pulse with a point-to-plane electrode configuration was used for the experiments. The concentration and production yield of hydrogen peroxide (H₂O₂) were quantitatively measured and orange II organic dye was treated, to evaluate the chemical properties of the discharge reactor. Experimental results show that the physical and chemical properties of water surface discharge are not influenced by pulse repetition rate, very different from those observed for under water discharge. The production yield of H₂O₂ and degradation rate per pulse of the dye did not significantly vary at different pulse repetition rates under a constant discharge mode on water surface. In addition, the solution temperature, pH, and conductivity for both water surface and underwater discharge reactors were measured to compare their plasma properties for different pulse repetition rates. The results confirm that surface discharge can be employed at high pulse repetition rates as a reliable and advantageous method for industrial and environmental decontamination applications.

  13. Dielectric Properties of Flocculated Water-in-Oil Emulsions

    Energy Technology Data Exchange (ETDEWEB)

    Skodvin, T.

    1995-12-31

    When an offshore oil field is near completion, water occupies a large fraction of the available pore volume. Thus, in collecting the oil and gas reserves, one has to deal with a high co-production of either formation- or injected water. This doctoral thesis focuses on the effect of water-in-oil emulsions on the dielectric properties, in particular the effect of flocculation. Various dielectric models are applied to obtain methods for qualitative and quantitative characterization of the flocculated state. Permittivity and measurement of dielectric properties are discussed as a basis for the interpretation of the dielectric properties of the emulsions. Various flocculation models are presented. It is concluded that the dielectric properties of water-in-oil emulsions are strongly influenced by continuously ongoing processes in the system. Because of flocculation and sedimentation the traditional dielectric mixture models cannot satisfactorily predict the dielectric behaviour. The experimentally obtained permittivities for the emulsions can be reproduced by including flocculation in the models and treating the floc aggregates as spheroids or subsystems with dielectric properties given by the degree of flocculation. The models discussed have difficulties reproducing the complete frequency behaviour found experimentally. This is probably because the dielectric relaxation may be influenced by processes not included in the models, such as the effects of dipolar or multipolar interactions between the droplets. For further research it is recommended that rheological and dielectric measurements be combined. 227 refs., 61 figs., 16 tabs.

  14. Study of Transitions between Wetting States on Microcavity Arrays by Optical Transmission Microscopy

    DEFF Research Database (Denmark)

    Søgaard, Emil; Andersen, Nis Korsgaard; Smistrup, Kristian

    2014-01-01

    compared the contact angle properties of two polymeric materials (COC and PP) with moderate hydrophobicity. We attributed the difference in the water repellency of the two materials to a difference in the wetting of their nanostructures. Our experimental observations thus indicate that both the diffusion...

  15. Influence of water-repellent treatment on the properties lime and lime pozzolan mortars

    Directory of Open Access Journals (Sweden)

    Fortes Revilla, C.

    2001-06-01

    Full Text Available The influence that water-repellent products can have on physical and micro-structural properties of lime mortars, and lime plus pozzolan mortars has been studied. Three water repellent products have been used. Mixes of the previously mentioned three water repellents plus a biocide product were also applied. Treatments make the total porosity and saturation coefficient of both mortars to decrease, while colorimetric coordinates bear little alteration. All treatments with water repellent products provided mortars with a hydrophobic property index close to 100%. Durability of such mortars has been also studied: salt crystallization test, frost-thaw and dry-wet cycles, as well as ultraviolet radiation test were carried out. Relationship between mortars behavior and their porosity and saturation coefficient were found.

    En el presente trabajo se ha estudiado la influencia de la aplicación de productos hidrofugantes a morteros de cal y morteros de cal y puzolana sobre sus propiedades físicas y microestructurales. Se han estudiado tres productos hidrofugantes. También han sido estudiados dichos productos junto con un biocida. La porosidad total y el coeficiente de saturación de ambos tipos de morteros se ve reducido por el efecto de los tratamientos mientras que las coordenadas colorimétricas se ven poco alteradas. Todos los tratamientos confieren un índice de hidrofobicidad a los morteros próximo al 100%. Asimismo, también se ha estudiado la durabilidad de dichos morteros frente a la cristalización de sales, hielo-deshielo, los ciclos de humedad-sequedad y radiaciones ultravioleta. Se relaciona el comportamiento de los morteros con su porosidad y el coeficiente de saturación.

  16. Water-repellent cellulose fiber networks with multifunctional properties.

    Science.gov (United States)

    Bayer, Ilker S; Fragouli, Despina; Attanasio, Agnese; Sorce, Barbara; Bertoni, Giovanni; Brescia, Rosaria; Di Corato, Riccardo; Pellegrino, Teresa; Kalyva, Maria; Sabella, Stefania; Pompa, Pier Paolo; Cingolani, Roberto; Athanassiou, Athanassia

    2011-10-01

    We demonstrate a simple but highly efficient technique to introduce multifunctional properties to cellulose fiber networks by wetting them with ethyl-cyanoacrylate monomer solutions containing various suspended organic submicrometer particles or inorganic nanoparticles. Solutions can be applied on cellulosic surfaces by simple solution casting techniques or by dip coating, both being suitable for large area applications. Immediately after solvent evaporation, ethyl-cyanoacrylate starts cross-linking around cellulose fibers under ambient conditions because of naturally occurring surface hydroxyl groups and adsorbed moisture, encapsulating them with a hydrophobic polymer shell. Furthermore, by dispersing various functional particles in the monomer solutions, hydrophobic ethyl-cyanoacrylate nanocomposites with desired functionalities can be formed around the cellulose fibers. To exhibit the versatility of the method, cellulose sheets were functionalized with different ethyl-cyanoacrylate nanocomposite shells comprising submicrometer wax or polytetrafluoroethylene particles for superhydophobicity, MnFe(2)O(4) nanoparticles for magnetic activity, CdSe/ZnS quantum dots for light emission, and silver nanoparticles for antimicrobial activity. Morphological and functional properties of each system have been studied by scanning and transmission electron microscopy, detailed contact angle measurements, light emission spectra and E. coli bacterial growth measurements. A plethora of potential applications can be envisioned for this technique, such as food and industrial packaging, document protection, catalytic cellulosic membranes, textronic (electrofunctional textiles), electromagnetic devices, authentication of valuable documents, and antimicrobial wound healing products to name a few.

  17. PHYSICOCHEMICAL PROPERTIES OF THE WATER DEPLETED OF HEAVY ISOTOPES

    Directory of Open Access Journals (Sweden)

    Vladislav V. Goncharuk

    2012-06-01

    Full Text Available Data on physicochemical properties of the light water (deuterium concentration is reduced to the ratio D/H = 4 ppm and that of the isotope of oxygen 18 – to the ratio 18O/16O = 750 ppm have been obtained. They include the melting and boiling points, kinematic viscosity, density, the spin-spin proton relaxation time, self-diffusion coefficients, and the small-angle laser light scattering. An explanation was proposed for the detected significant changes of the light water as compared with the high-resistivity water having geochemically ordinary isotope composition.

  18. 油菜角果外表面浸润性试验研究%Experimental Study of Wetting Property of Rape Pod Surface

    Institute of Scientific and Technical Information of China (English)

    徐立章; 马征; 李耀明

    2014-01-01

    油菜脱出物的浸润特性研究有助于解决其粘筛堵孔难题。本文以油菜脱出物中主要成分之一的油菜角果为研究对象,以两种典型液体为液相,采用 CAM 101型接触角测量仪对6个品种的油菜角果外表面接触角进行测试试验,并对试验结果进行了对比分析和方差分析。结果表明:油菜角果外表面普遍显示出亲水亲油特性,油菜品种对油菜角果外表面的浸润性无直接影响,但油菜品种会因对其成熟度的影响而间接地对其角果外表面浸润性产生影响。%Research on permeability of threshed oilseed rape mixture helps to solve the problems of adhesion onto sieve and blocking of sieve opening .Silique is one of the main oilseed rape mixtures and considered as study object in this pa-per .With two typical liquid as liquid , outside surface contact angles of six types of rape silique were tested by contact an-gle meter CAM101, and the test result was analyzed by comparison and contrast method and variance method .The result showed that outside surfaces of silique were universally oil-wet and water-loving .Rape variety had no direct influence on permeability of rape silique outside surface , but it may impact on rape maturity and then it brought some influences on permeability of rape silique outside surface indirectly .

  19. Volumetric properties of water/AOT/isooctane microemulsions.

    Science.gov (United States)

    Du, Changfei; He, Wei; Yin, Tianxiang; Shen, Weiguo

    2014-12-23

    The densities of AOT/isooctane micelles and water/AOT/isooctane microemulsions with the molar ratios R of water to AOT being 2, 8, 10, 12, 16, 18, 20, 25, 30, and 40 were measured at 303.15 K. The apparent specific volumes of AOT and the quasi-component water/AOT at various concentrations were calculated and used to estimate the volumetric properties of AOT and water in the droplets and in the continuous oil phase, to discuss the interaction between the droplets, and to determine the critical micelle concentration and the critical microemulsion concentrations. A thermodynamic model was proposed to analysis the stability boundary of the microemulsion droplets, which confirms the maximum value of R being about 65 for the stable AOT/water/isooctane microemulsion droplets.

  20. Tensile properties of ADI material in water and gaseous environments

    Energy Technology Data Exchange (ETDEWEB)

    Rajnovic, Dragan, E-mail: draganr@uns.ac.rs [Faculty of Technical Sciences, University of Novi Sad, Trg D. Obradovića 6, 21000 Novi Sad (Serbia); Balos, Sebastian; Sidjanin, Leposava [Faculty of Technical Sciences, University of Novi Sad, Trg D. Obradovića 6, 21000 Novi Sad (Serbia); Eric Cekic, Olivera [Innovation Centre, Faculty of Mechanical Engineering, University of Belgrade, Kraljice Marije 16, 11120 Belgrade (Serbia); Grbovic Novakovic, Jasmina [Vinca Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11000 Belgrade (Serbia)

    2015-03-15

    Austempered ductile iron (ADI) is an advanced type of heat treated ductile iron, having comparable mechanical properties as forged steels. However, it was found that in contact with water the mechanical properties of austempered ductile irons decrease, especially their ductility. Despite considerable scientific attention, the cause of this phenomenon remains unclear. Some authors suggested that hydrogen or small atom chemisorption causes the weakening of the surface atomic bonds. To get additional reliable data of that phenomenon, in this paper, two different types of austempered ductile irons were tensile tested in various environments, such as: argon, helium, hydrogen gas and water. It was found that only the hydrogen gas and water gave a statistically significant decrease in mechanical properties, i.e. cause embrittlement. Furthermore, the fracture surface analysis revealed that the morphology of the embrittled zone near the specimen surface shares similarities to the fatigue micro-containing striation-like lines, which indicates that the morphology of the brittle zone may be caused by cyclic local-chemisorption, micro-embrittlement and local-fracture. - Highlights: • In contact with water and other liquids the ADI suddenly exhibits embrittlement. • The embrittlement is more pronounced in water than in the gaseous hydrogen. • The hydrogen chemisorption into ADI surface causes the formation of a brittle zone. • The ADI austempered at lower temperatures (300 °C) is more resistant to embrittlement.

  1. Volumetric properties of human islet amyloid polypeptide in liquid water.

    Science.gov (United States)

    Brovchenko, I; Andrews, M N; Oleinikova, A

    2010-04-28

    The volumetric properties of human islet amyloid polypeptide (hIAPP) in water were studied in a wide temperature range by computer simulations. The intrinsic density rho(p) and the intrinsic thermal expansion coefficient alpha(p) of hIAPP were evaluated by taking into account the difference between the volumetric properties of hydration and bulk water. The density of hydration water rho(h) was found to decrease almost linearly with temperature upon heating and its thermal expansion coefficient was found to be notably higher than that of bulk water. The peptide surface exposed to water is more hydrophobic and its rho(h) is smaller in conformation with a larger number of intrapeptide hydrogen bonds. The two hIAPP peptides studied (with and without disulfide bridge) show negative alpha(p), which is close to zero at 250 K and decreases to approximately -1.5 x 10(-3) K(-1) upon heating to 450 K. The analysis of various structural properties of peptides shows a correlation between the intrinsic peptide volumes and the number of intrapeptide hydrogen bonds. The obtained negative values of alpha(p) can be attributed to the shrinkage of the inner voids of the peptides upon heating.

  2. Squeezing wetting and nonwetting liquids.

    Science.gov (United States)

    Samoilov, V N; Persson, B N J

    2004-01-22

    We present molecular-dynamics results for the squeezing of octane (C8H18) between two approaching solid elastic walls with different wetting properties. The interaction energy between the octane bead units and the solid walls is varied from a very small value (1 meV), corresponding to a nonwetting surface with a very large contact angle (nearly 180 degrees), to a high value (18.6 meV) corresponding to complete wetting. When at least one of the solid walls is wetted by octane we observe well defined molecular layers develop in the lubricant film when the thickness of the film is of the order of a few atomic diameters. An external squeezing-pressure induces discontinuous, thermally activated changes in the number n of lubricant layers (n-->n-1 layering transitions). With increasing interaction energy between the octane bead units and the solid walls, the transitions from n to n-1 layers occur at higher average pressure. This results from the increasing activation barrier to nucleate the squeeze-out with increasing lubricant-wall binding energy (per unit surface area) in the contact zone. Thus, strongly wetting lubricant fluids are better boundary lubricants than the less wetting ones, and this should result in less wear. We analyze in detail the effect of capillary bridge formation (in the wetting case) and droplets formation (in the nonwetting case) on the forces exerted by the lubricant on the walls. For the latter case small liquid droplets may be trapped at the interface, resulting in a repulsive force between the walls during squeezing, until the solid walls come into direct contact, where the wall-wall interaction may be initially attractive. This effect is made use of in some practical applications, and we give one illustration involving conditioners for hair care application.

  3. Synthesis and properties of water-soluble asterisk molecules.

    Science.gov (United States)

    Menger, Fredric M; Azov, Vladimir A

    2002-09-18

    An asterisk is comprised of six semirigid arms projecting from a benzene nucleus. In the case at hand, asterisks were synthesized with one, two, or three aromatic rings (connected by sulfur atoms) in each of the six arms. A phosphomonoester at the termini of each arm solubilized the asterisks in water. The colloidal properties of these amphiphilic molecules were investigated by UV-vis and fluorescence spectroscopy, calorimetry, light scattering, surface tensiometry, and pulse-gradient spin-echo NMR. Solubility, solubilization, metal binding, and micelle "seeding" experiments were also carried out. Chain-conformation and supramolecular assembly into remarkable molecular "scrolls" were investigated by X-ray analysis and electron microscopy, respectively. One of the more interesting properties of the asterisks is that they remain monomeric in water despite having as many as 19 hydrophobic aromatic rings exposed to the water. The reasons for this behavior, and the possibility of exploiting it for constructing enzyme models free from aggregation equilibria, are discussed.

  4. Investigation of radiological properties and water equivalency of PRESAGE dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Gorjiara, Tina; Hill, Robin; Kuncic, Zdenka; Adamovics, John; Bosi, Stephen; Kim, Jung-Ha; Baldock, Clive [Institute of Medical Physics, School of Physics, University of Sydney, New South Wales 2006 (Australia); Institute of Medical Physics, School of Physics, University of Sydney, New South Wales 2006 (Australia) and Department of Radiation Oncology, Royal Prince Alfred Hospital, Sydney, New South Wales 2050 (Australia); Institute of Medical Physics, School of Physics, University of Sydney, New South Wales 2006 (Australia); Department of Chemistry and Biology, Rider University, Lawrenceville, New Jersey 08648 (United States); Institute of Medical Physics, School of Physics, University of Sydney, New South Wales 2006 (Australia) and Department of Radiation Oncology, Prince of Wales Hospital, Randwick, New South Wales 2031 (Australia); Institute of Medical Physics, School of Physics, University of Sydney, New South Wales 2006 (Australia)

    2011-04-15

    Purpose: PRESAGE is a dosimeter made of polyurethane, which is suitable for 3D dosimetry in modern radiation treatment techniques. Since an ideal dosimeter is radiologically water equivalent, the authors investigated water equivalency and the radiological properties of three different PRESAGE formulations that differ primarily in their elemental compositions. Two of the formulations are new and have lower halogen content than the original formulation. Methods: The radiological water equivalence was assessed by comparing the densities, interaction probabilities, and radiation dosimetry properties of the three different PRESAGE formulations to the corresponding values for water. The relative depth doses were calculated using Monte Carlo methods for 50, 100, 200, and 350 kVp and 6 MV x-ray beams. Results: The mass densities of the three PRESAGE formulations varied from 5.3% higher than that of water to as much as 10% higher than that of water for the original formulation. The probability of photoelectric absorption in the three different PRESAGE formulations varied from 2.2 times greater than that of water for the new formulations to 3.5 times greater than that of water for the original formulation. The mass attenuation coefficient for the three formulations is 12%-50% higher than the value for water. These differences occur over an energy range (10-100 keV) in which the photoelectric effect is the dominant interaction. The collision mass stopping powers of the relatively lower halogen-containing PRESAGE formulations also exhibit marginally better water equivalency than the original higher halogen-containing PRESAGE formulation. Furthermore, the depth dose curves for the lower halogen-containing PRESAGE formulations are slightly closer to that of water for a 6 MV beam. In the kilovoltage energy range, the depth dose curves for the lower halogen-containing PRESAGE formulations are in better agreement with water than the original PRESAGE formulation. Conclusions: Based

  5. The effects of wetting layer on electronic and optical properties of intersubband P-to-S transitions in strained dome-shaped InAs/GaAs quantum dots

    Directory of Open Access Journals (Sweden)

    Mohammadreza Shahzadeh

    2014-06-01

    Full Text Available The authors report on the impact of wetting layer thickness and quantum dot size on the electronic and optical properties of dome-shaped InAs/GaAs quantum dots (QDs with strained potential. Two wetting layer thicknesses of 0.5 and 2.0 nm were compared. A strong size dependence of P-to-S transition energy, transition dipole moment, oscillator strength, and linear and third-order nonlinear susceptibilities were concluded. The P-to-S transition dipole moment was shown to be purely in-plane polarization. The linear and nonlinear absorption and dispersion showed a red shift when the wetting layer thickness was increased. Our results revealed that the nonlinear susceptibility is much more sensitive to QD size compared to the linear susceptibility. An interpretation of the results was presented based on the probability density of finding the electron inside the dot and wetting layer. The results are in good agreement with previously reported experimental data.

  6. Development and application of a comprehensive simulation model to evaluate impacts of watershed structures and irrigation water use on streamflow and groundwater: The case of Wet Walnut Creek Watershed, Kansas, USA

    Science.gov (United States)

    Ramireddygari, S.R.; Sophocleous, M.A.; Koelliker, J.K.; Perkins, S.P.; Govindaraju, R.S.

    2000-01-01

    This paper presents the results of a comprehensive modeling study of surface and groundwater systems, including stream-aquifer interactions, for the Wet Walnut Creek Watershed in west-central Kansas. The main objective of this study was to assess the impacts of watershed structures and irrigation water use on streamflow and groundwater levels, which in turn affect availability of water for the Cheyenne Bottoms Wildlife Refuge Management area. The surface-water flow model, POTYLDR, and the groundwater flow model, MODFLOW, were combined into an integrated, watershed-scale, continuous simulation model. Major revisions and enhancements were made to the POTYLDR and MODFLOW models for simulating the detailed hydrologic budget for the Wet Walnut Creek Watershed. The computer simulation model was calibrated and verified using historical streamflow records (at Albert and Nekoma gaging stations), reported irrigation water use, observed water-level elevations in watershed structure pools, and groundwater levels in the alluvial aquifer system. To assess the impact of watershed structures and irrigation water use on streamflow and groundwater levels, a number of hypothetical management scenarios were simulated under various operational criteria for watershed structures and different annual limits on water use for irrigation. A standard 'base case' was defined to allow comparative analysis of the results of different scenarios. The simulated streamflows showed that watershed structures decrease both streamflows and groundwater levels in the watershed. The amount of water used for irrigation has a substantial effect on the total simulated streamflow and groundwater levels, indicating that irrigation is a major budget item for managing water resources in the watershed. (C) 2000 Elsevier Science B.V.This paper presents the results of a comprehensive modeling study of surface and groundwater systems, including stream-aquifer interactions, for the Wet Walnut Creek Watershed in west

  7. Effect of fibrous filter properties on the oil-in-water-emulsion separation and filtration performance.

    Science.gov (United States)

    Bansal, Swarna; von Arnim, Volkmar; Stegmaier, Thomas; Planck, Heinrich

    2011-06-15

    Separation of secondary emulsions of dispersed droplet size less than 10 μm, by means of fibrous medium is a very complex but important process. The study investigates the influence of thin fibrous filter properties, i.e. surface energy, pore size and porosity on the separation performance of an isooctane in water emulsion (0.2%, mean drop size 2 μm). Experiments were carried out on five different filter media with a wide variation in their pore size (2-51 μm), surface energy (14-46 mN/m) and porosity (0.46-0.87) at similar process conditions. Filter media with different wettability are obtained by applying various hydrophobic and hydrophilic coatings. All the used coatings contain nanoparticles (25 nm) to impart nanoscale surface roughness at the single fiber surface. Besides emulsion properties and operating conditions, the phase separation mechanism and performance highly depends on pore size, surface energy and porosity of the filter media. More complete coalescence takes place at reduced pore size and at a surface preferentially wetted by the dispersed phase. Whereas when the pore size equals to the influent droplet size, then the surface wettability of filter is less effective and the separation mechanism is governed by inflow velocity. The emulsion inflow velocity and pressure drop are significantly affected by the filter media air permeability but do not depend on filter surface energy.

  8. STUDY ON WET STRENGTH PERFORMANCE OF KENAF MULCH

    Institute of Scientific and Technical Information of China (English)

    Jinghui Zhou; Xinge Wu; Hongwei Zhu

    2004-01-01

    Optimum applied technical conditions of wet strength agent for kenaf mulch were studied in this article. Breaking length, wet-dry strength ratio, tear index and burst index of kenaf mulch were measured and optimum wet strength agent was selected. The aim is to make mulch have properties of heat preservation, humidity preservation, growth prompting, biodegradation and maximum wet strength and to improve impact resistance of mulch to rainwater so as to assure growth of plant and replace plastic film.

  9. Geotechnical properties of two siliceous cores from the central Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Khadge, N.H.

    Physical properties of the siliceous sediments from the Central Indian Basin are measured on two short cores. The properties such as water content, Atterberg limits, porosity specific gravity, wet density show the medium to high plastic sediment...

  10. Capillarity and wetting of carbon dioxide and brine during drainage in Berea sandstone at reservoir conditions

    Science.gov (United States)

    Al-Menhali, Ali; Niu, Ben; Krevor, Samuel

    2015-10-01

    The wettability of CO2-brine-rock systems will have a major impact on the management of carbon sequestration in subsurface geological formations. Recent contact angle measurement studies have reported sensitivity in wetting behavior of this system to pressure, temperature, and brine salinity. We report observations of the impact of reservoir conditions on the capillary pressure characteristic curve and relative permeability of a single Berea sandstone during drainage—CO2 displacing brine—through effects on the wetting state. Eight reservoir condition drainage capillary pressure characteristic curves were measured using CO2 and brine in a single fired Berea sandstone at pressures (5-20 MPa), temperatures (25-50°C), and ionic strengths (0-5 mol kg-1 NaCl). A ninth measurement using a N2-water system provided a benchmark for capillarity with a strongly water wet system. The capillary pressure curves from each of the tests were found to be similar to the N2-water curve when scaled by the interfacial tension. Reservoir conditions were not found to have a significant impact on the capillary strength of the CO2-brine system during drainage through a variation in the wetting state. Two steady-state relative permeability measurements with CO2 and brine and one with N2 and brine similarly show little variation between conditions, consistent with the observation that the CO2-brine-sandstone system is water wetting and multiphase flow properties invariant across a wide range of reservoir conditions.

  11. Measuring the specific surface area of wet snow using 1310 nm reflectance

    Directory of Open Access Journals (Sweden)

    J.-C. Gallet

    2013-10-01

    Full Text Available The specific surface area (SSA of snow can be used as an objective measurement of grain size and is therefore a central variable to describe snow physical properties such as albedo. Snow SSA can now be easily measured in the field using optical methods based on infrared reflectance. However, existing optical methods have only been validated for dry snow. Here we test the possibility to use the DUFISSS instrument, based on the measurement of the 1310 nm reflectance of snow with an integrating sphere, to measure the SSA of wet snow. We perform cold room experiments where we measure the SSA of a wet snow sample, freeze it and measure it again, to quantify the difference in reflectance between frozen and wet snow. We study snow samples in the SSA range 12–37 m2 kg−1 and in the mass liquid water content range 5–32%. We conclude that the SSA of wet snow can be obtained from the measurement of its 1310 nm reflectance using three simple steps. In most cases, the SSA thus obtained is less than 10% different from the value that would have been obtained if the sample had been considered dry, so that the three simple steps constitute a minor correction. We also run two optical models to interpret the results, but no model reproduces correctly the water-ice distribution in wet snow, so that their predictions of wet snow reflectance are imperfect.

  12. Wetting transitions of simple liquid films adsorbed on selfassembled monolayer substrates: an ellipsometric study

    Science.gov (United States)

    Batchelder, D. N.; Cheng, Y. L.; Evans, S. D.; Henderson, J. R.

    We report on an ellipsometric experimental study designed to explore the relevance of the wetting phase diagram predicted by liquid state physics of basic models, to the wide class of simple organic liquid films that adsorb from saturated vapour onto planar substrates at room temperature. The wetting properties are explored by measuring adsorption isotherms in the approach to saturation, in particular, for adsorption of n -hexane on a variety of specially constructed substrates (self-assembled monolayers) spanning a wide range of surface energy, and by carrying out the microscopic equivalent of contact angle experiments at saturation. We locate a wetting transition, which in our case is continuous, and then study its properties in detail. The general prediction of the wetting phase diagram, that wetting transitions should be ubiquitous in nature and readily located via control over the substrate field, is supported by our data, but the quantitative nature of the thick film adsorption regime is not in agreement with Lifshitz theory. This conclusion supports the work of a variety of earlier related studies, but contrasts with recent results for adsorption onto the surface of water. In addition, the correlation length determined from our complete wetting adsorption isotherms is mesoscopic, suggesting that equilibrium statistical mechanics of simple models of inhomogeneous fluids cannot explain the data.

  13. The Paradox of a Wet (High H2O) and Dry (Low H2O/Ce) Mantle: High Water Concentrations in Mantle Garnet Pyroxenites from Hawaii

    Science.gov (United States)

    Peslier, Anne H.; Bizimis, Michael

    2013-01-01

    Water dissolved as trace amounts in anhydrous minerals has a large influence on the melting behavior and physical properties of the mantle. The water concentration of the oceanic mantle is inferred from the analyses of Mid-Ocean Ridge Basalt (MORB) and Oceanic Island Basalt (OIB). but there is little data from actual mantle samples. Moreover, enriched mineralogies (pyroxenites, eclogites) are thought as important sources of heterogeneity in the mantle, but their water concentrations and their effect on the water budget and cycling in the mantle are virtually unknown. Here, we analyzed by FTIR water in garnet clinopyroxenite xenoliths from Salt Lake Crater, Oahu, Hawaii. These pyroxenites are high-pressure (>20kb) crystal fractionates from alkalic melts. The clinopyroxenes (cpx) have 260 to 576 ppm wt H2O, with the least differentiated samples (Mg#>0.8) in the 400-500 ppm range. Orthopyroxene (opx) contain 117-265 ppm H2O, about half of that of cpx, consistent with other natural sample studies, but lower than cpx/opx equilibrium from experimental data. The pyroxenite cpx and opx H2O concentrations are at the high-end of on-and off-craton peridotite xenolith concentrations and those of Hawaiian spinel peridotites. In contrast, garnet has extremely low water contents (Ce is 69 +/-35, lower than estimates of the MORB source (approx 150) or FOZO, C (200-250) mantle component, but consistent with "dry" EM sources (Ce, and may contribute to EM-type OIB sources, like that of Samoa basalts. Therefore, a low H2O/Ce mantle source may not necessarily be "dry".

  14. Non-isothermal wetting during impact of millimeter size water drop on a flat substrate: numerical investigation and comparison with high-speed visualization experiments

    CERN Document Server

    Bhardwaj, Rajneesh

    2010-01-01

    The objective of this work is to develop and validate a numerical model to study wetting during the impact of millimeter-size drops on a flat, smooth, solid substrate under isothermal or non-isothermal conditions. A finite-element modeling is used to simulate the transient fluid dynamics and heat transfer, considering Laplace forces on the liquid-gas boundary. The Lagrangian scheme allows a very precise tracking of the free surface deformation. In this work, the numerical model is extended to account for a temperature-dependent viscosity and for dynamic wetting at the contact line. Numerical results are presented to study the influence of the kinetic wetting parameter on the wetting incipience and behavior. Our results show the influence of wetting on the spreading and the transient drop shape. Also, numerical results are compared with high-speed visualization, for cases of isothermal and non-isothermal impact. Matching between simulations and high-speed visualization allows the determination of the value of ...

  15. Thermal properties of phosphoric acid-doped polybenzimidazole membranes in water and methanol-water mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Nores-Pondal, Federico J.; Corti, Horacio R. [Grupo de Pilas de Combustible, Departamento de Fisica de la Materia Condensada, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica (CNEA), Av. General Paz 1499, B1650KNA San Martin, Buenos Aires (Argentina); Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Buera, M. Pilar [Consejo Nacional de Investigaciones Cientificas y Tecnicas (Argentina); Departamento de Industrias, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Av. Cantilo s/n, Ciudad Universitaria (1428) Buenos Aires (Argentina)

    2010-10-01

    The thermal properties of phosphoric acid-doped poly[2-2'-(m-phenylene)-5-5' bi-benzimidazole] (PBI) and poly[2,5-benzimidazole] (ABPBI) membranes, ionomeric materials with promising properties to be used as electrolytes in direct methanol and in high temperature polymer electrolyte membrane (PEM) fuel cells, were studied by means of differential scanning calorimetry (DSC) technique in the temperature range from -145 C to 200 C. The DSC scans of samples equilibrated in water at different relative humidities (RH) and in liquid water-methanol mixtures were analyzed in relation to glass transition, water crystallization/melting and solvent desorption in different temperature regions. The thermal relaxation observed in the very low temperature region could be ascribed to the glass transition of the H{sub 3}PO{sub 4}-H{sub 2}O mixture confined in the polymeric matrix. After cooling the samples up to -145 C, frozen water was detected in PBI and ABPBI at different RH, although at 100% RH less amount of water had crystallized than that observed in Nafion membranes under the same conditions. Even more important is the fact that the freezing degree of water is much lower in ABPBI membranes equilibrated in liquid water-methanol mixtures than that observed for PBI and, in a previous study, for Nafion. Thus, apart from other well known properties, acid-doped ABPBI emerges as an excellent ionomer for applications in direct methanol fuel cells working in cold environments. (author)

  16. Biological properties of water-soluble phosphorhydrazone dendrimers

    Directory of Open Access Journals (Sweden)

    Anne-Marie Caminade

    2013-01-01

    Full Text Available Dendrimers are hyperbranched and perfectly defined macromolecules, constituted of branches emanating from a central core in an iterative fashion. Phosphorhydrazone dendrimers constitute a special family of dendrimers, possessing one phosphorus atom at each branching point. The internal structure of these dendrimers is hydrophobic, but hydrophilic terminal groups can induce the solubility of the whole structure in water. Indeed, the properties of these compounds are mainly driven by the type of terminal groups their bear; this is especially true for the biological properties. For instance, positively charged terminal groups are efficient for transfection experiments, as drug carriers, as anti-prion agents, and as inhibitor of the aggregation of Alzheimer's peptides, whereas negatively charged dendrimers have anti-HIV properties and can influence the human immune system, leading to anti-inflammatory properties usable against rheumatoid arthritis. This review will give the most representative examples of the biological properties of water-soluble phosphorhydrazone dendrimers, organized depending on the type of terminal groups they bear.

  17. Efeito da profundidade de soldagem no hidrogênio difusível de soldas molhadas Effect of water depth on diffusible hydrogen on wet welds

    Directory of Open Access Journals (Sweden)

    Weslley Carlos Dias da Silva

    2012-12-01

    Full Text Available Em soldagem subaquática molhada, a ocorrência de poros e trincas a frio pode ter um efeito bastante prejudicial nas propriedades mecânicas da junta soldada. O hidrogênio contribui diretamente para o aparecimento destas duas descontinuidades. A quantidade de hidrogênio difusível (Hdif no metal de solda pode ser influenciada por diversos fatores. Todavia, pouco se sabe sobre a influência da profundidade de soldagem (pressão sobre a quantidade de Hdif no metal de solda. Neste trabalho, diversas medições de hidrogênio difusível foram feitas nas profundidades de 0,30 m, 10 m e 20 m e 30 m em soldagem molhada. O consumível utilizado foi o eletrodo comercial E6013 envernizado. As medições de hidrogênio difusível foram feitas através do método da cromatografia. Para medição de porosidade foi utilizado o método macrográfico e um programa analisador de imagem. O hidrogênio residual também foi medido. Os resultados mostraram que o hidrogênio difusível reduziu significativamente com o aumento da pressão hidrostática ao contrário da porosidade, que aumentou com o aumento da pressão hidrostática. Não se observou alterações apreciáveis no hidrogênio residual do metal de solda. Desta forma, é possível concluir que a profundidade de soldagem afeta diversos aspectos da soldagem subaquática molhada, em especial, o hidrogênio difusível e porosidade, conforme foi observado neste trabalho.In underwater wet welding, cold cracking and pores might have a deleterious effect in the mechanical properties of welded joint. The hydrogen might act in the occurrence of theses discontinuities. The amount of diffusible hydrogen in the weld metal can be influenced by several factors. However, not yet known whether the depth of welding (pressure affects the amount of diffusible hydrogen in weld metal. In this work, several measurements of diffusible hydrogen were made at following depth: 0.30 m, 10 m, 20 m and 30 m atwet welding. The

  18. Evaluation of Water Resistance and Diffusion Properties of Paint Materials

    Directory of Open Access Journals (Sweden)

    J. Drchalová

    2001-01-01

    Full Text Available A simple method is presented for evaluating the water-proofness quality of paints on lining materials. The method is based on measuring the integral capillarity in dependence on time, and then comparing this value to the value determined for the basic lining material. Measurements of the effective water vapor permeability then provide information on the risk of condensation which may increase after applying the paint. A practical application of the method is performed with four Karlocolor paints on glass concrete substrates. All the Karlocolor paints are found to be very effective materials for driven rain protection. The diffusion properties of all the paints are found to be excellent.

  19. WetVegEurope

    NARCIS (Netherlands)

    Landucci, Flavia; Řezníčková, Marcela; Šumberová, Kateřina; Hennekens, S.M.; Schaminée, J.H.J.

    2015-01-01

    WetVegEurope is a research project (http://www.sci.muni.cz/botany/vegsci/wetveg) whose goal is to provide a synthesized formalized classification of the aquatic and marsh vegetation across Europe at the level of phytosociological associations. In order to achieve the project objective, a WetVegEu

  20. Effects of Coal—Water Mixture Properties in Atomization

    Institute of Scientific and Technical Information of China (English)

    DavidJ.Wildman; JamesM.Ekmann

    1994-01-01

    Recent suggested CWM applications include using filter cake material and mill tailings as coal sources.Neither coal type nor particle size distribution are necessarily well suited for coal-water mixture production.Slurries were prepared with and without additives and attempts were made to characterize their rheological properties and atomize these materials,Limits of operation and the value of existing rheological instrumentation and methods were investigated.Effects of changes in particle size distribution are discussed.

  1. Reverse osmosis membrane of high urea rejection properties. [water purification

    Science.gov (United States)

    Johnson, C. C.; Wydeven, T. J. (Inventor)

    1980-01-01

    Polymeric membranes suitable for use in reverse osmosis water purification because of their high urea and salt rejection properties are prepared by generating a plasma of an unsaturated hydrocarbon monomer and nitrogen gas from an electrical source. A polymeric membrane is formed by depositing a polymer of the unsaturated monomer from the plasma onto a substrate, so that nitrogen from the nitrogen gas is incorporated within the polymer in a chemically combined form.

  2. Forced wetting of a reactive surface.

    Science.gov (United States)

    Blake, T D

    2012-11-01

    The dynamic wetting of water on gelatin-coated poly(ethylene terephthalate) (GC-PET) has been investigated by forced wetting over a wide speed range and compared with earlier data obtained with unmodified PET. The results were analysed according to the molecular-kinetic theory of dynamic wetting (MKT). Both substrates show complex behaviour, with separate low- and high-speed modes. For the GC-PET, this is attributed to a rapid change in the wettability of the substrate on contact with water, specifically a surface molecular transformation from hydrophobic to hydrophilic. This results in a smooth wetting transition from one mode to the other. For the PET, the bimodal behaviour is attributed to surface heterogeneity, with the low-speed dynamics dominated by interactions with polar sites on the substrate that become masked at higher speeds. In this case, the transition is discontinuous. The study has general ramifications for the investigation of any wetting processes in which a physicochemical transformation takes place at the solid surface on contact with the liquid. In particular, it shows how forced wetting, combined with the MKT, can reveal subtle details of the processes involved. It is unlikely that similar insight could be gained from spontaneous wetting studies, such as spreading drops.

  3. The effect on slurry water as a fresh water replacement in concrete properties

    Science.gov (United States)

    Kadir, Aeslina Abdul; Shahidan, Shahiron; Hai Yee, Lau; Ikhmal Haqeem Hassan, Mohd; Bakri Abdullah, Mohd Mustafa Al

    2016-06-01

    Concrete is the most widely used engineering material in the world and one of the largest water consuming industries. Consequently, the concrete manufacturer, ready mixed concrete plant is increased dramatically due to high demand from urban development project. At the same time, slurry water was generated and leading to environmental problems. Thus, this paper is to investigate the effect of using slurry water on concrete properties in term of mechanical properties. The basic wastewater characterization was investigated according to USEPA (Method 150.1 & 300.0) while the mechanical property of concrete with slurry water was compared according to ASTM C1602 and BS EN 1008 standards. In this research, the compressive strength, modulus of elasticity and tensile strength were studied. The percentage of wastewater replaced in concrete mixing was ranging from 0% up to 50%. In addition, the resulted also suggested that the concrete with 20% replacement of slurry water was achieved the highest compressive strength and modulus of elasticity compared to other percentages. Moreover, the results also recommended that concrete with slurry water mix have better compressive strength compared to control mix concrete.

  4. [KEEPING THE ELECTRON-DONOR PROPERTIES OF DRINKING WATER].

    Science.gov (United States)

    Gibert, K K; Stekhin, A A; Iakovleva, G V; Sul'ina, Iu S

    2015-01-01

    In a study there was performed the experimental evaluation of long-term structural--physical changes of the phase of associated water in drinking water treated in hypomagnetic conditions according to the the technology providing the retention of of ortho/para isomers of water in the presence of a catalyst--triplet oxygen. According to the results of measurements ofparameters of nano-associates formed in the water there was found a series ofconsistencies, allowing to determine the mechanisms of the impact of hypomagnetic treatment on the catalytic properties ofwater and long-term stability of its activated state, that provides the long-term maintenance of high biological activity of drinking water. In particular, under hypomagnetic conditions of the treatment there is formed denser packing of amorphous ice--VI in the composition of associates peroxide, serving as a kind of "reservoir" of atmospheric gases. In such a "reservoir" there realized higher pressure, compared with normal geophysical conditions, that stimulates the gas-phase reactions with the formation of dimers and trimers of oxygen existing in the 2-electron--active configurations with binding energies of 0.3 eVand ~0.2 eV providing phase modulation, resulting in condensation of environment additional electrons on paramagnetic oxygen, which provides the long-term maintenance of the electron--donor ability of water and electrically non-equilibrium state.

  5. Local properties of countercurrent stratified steam-water flow

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H J

    1985-10-01

    A study of steam condensation in countercurrent stratified flow of steam and subcooled water has been carried out in a rectangular channel/flat plate geometry over a wide range of inclination angles (4/sup 0/-87/sup 0/) at several aspect ratios. Variables were inlet water and steam flow rates, and inlet water temperature. Local condensation rates and pressure gradients were measured, and local condensation heat transfer coefficients and interfacial shear stress were calculated. Contact probe traverses of the surface waves were made, which allowed a statistical analysis of the wave properties. The local condensation Nusselt number was correlated in terms of local water and steam Reynolds or Froude numbers, as well as the liquid Prandtl number. A turbulence-centered model developed by Theofanous, et al. principally for gas absorption in several geometries, was modified. A correlation for the interfacial shear stress and the pressure gradient agreed with measured values. Mean water layer thicknesses were calculated. Interfacial wave parameters, such as the mean water layer thickness, liquid fraction probability distribution, wave amplitude and wave frequency, are analyzed.

  6. Wetting and Non-Wetting Models of Black Carbon Activation

    Science.gov (United States)

    Henson, B. F.; Laura, S.

    2006-12-01

    We present the results of recent modeling studies on the activation of black carbon (BC) aerosol to form cloud condensation nuclei (CCN). We use a model of BC activation based on a general modification of the Koehler equation for insoluble activation in which we introduce a term based on the activity of water adsorbed on the particle surface. We parameterize the model using the free energy of adsorption, a parameter directly comparable to laboratory measurements of water adsorption on carbon. Although the model of the water- surface interaction is general, the form of the activation equation that results depends upon a further model of the distribution of water on the particle. One possible model involves the symmetric growth of a water shell around the isoluble particle core (wetting). This model predicts upper and lower bounding curves for the activation supersaturation given by the range of water interaction energies from hydrophobic to hydrophilic which are in agreement with a large body of recent activation data. The resulting activation diameters are from 3 to 10 times smaller than activation of soluble particles of identical dry diameter. Another possible model involves an exluded liquid droplet growing in contact with the particle (non-wetting). The geometry of this model much more resembles classic assumptions of heterogeneous nucleation theory. This model can yield extremely high activation supersaturation as a function of diameter, as has been observed in some experiments, and enables calculations in agreement with some of these results. We discuss these two geometrical models of water growth, the different behaviors predicted by the resulting activation equation, and the means to determine which model of growth is appropriate for a given BC particle characterized by either water interaction energy or morphology. These simple models enable an efficient and physically reasonable means to calculate the activation of BC aerosol to form CCN based upon a

  7. Distribution characteristics of soil water under partial wetted irrigation and it's potential environmental effects%局部湿润灌溉土壤水分分布特征及其潜在环境效应

    Institute of Scientific and Technical Information of China (English)

    徐俊增; 卫琦; 彭世彰; 于艳梅; 张晓勇

    2012-01-01

    针对多种局部湿润的灌溉技术,在概括其湿润体湿润特征的基础上,总结了湿润体分布特征的影响因素、局部湿润灌溉土壤水分运动模拟和局部湿润灌溉的农田环境效应,并从农田土壤氧化亚氮排放与土壤水分关系和局部灌溉土壤水分非均匀分布特征角度,提出应该开展不同湿润体形式下土壤氧化亚氮排放规律及其对土壤水分布的响应、高效减排的局部湿润灌溉灌水技术参数优化角度开展新的研究.%The characteristics of wet body for several partial wet irrigation techniques were briefly introduced , as well as the influencing factors and the simulation of soil moisture moving and the environmental effect caused by partial wet irrigation. Then from nitrous oxide emission of agro-soils and its relation to soil moisture variation the non-uniform characteristics of soil moisture were put forward, some should be studied in future, included nitrous oxide emission rule and its responses to soil water distribution under partial wet irrigation, irrigation parameters optimization of partial wet irrigation for high irrigation uniformity and low nitrous oxide emission.

  8. Wetting behavior of alternative solder alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Vianco, P.T.; Hernandez, C.L.; Rejent, J.A.

    1993-07-01

    Recent economic and environmental issues have stimulated interest in solder alloys other than the traditional Sn-Pb eutectic or near eutectic composition. Preliminary evaluations suggest that several of these alloys approach the baseline properties (wetting, mechanical, thermal, and electrical) of the Sn-Pb solders. Final alloy acceptance will require major revisions to existing industrial and military soldering specifications. Bulk alloy and solder joint properties are consequently being investigated to validate their producibility and reliability. The work reported in this paper examines the wetting behavior of several of the more promising commercial alloys on copper substrates. Solder wettability was determined by the meniscometer and wetting balance techniques. The wetting results suggest that several of the alternative solders would satisfy pretinning and surface mount soldering applications. Their use on plated through hole technology might be more difficult since the alloys generally did not spread or flow as well as the 60Sn-40Pb solder.

  9. Water properties in fern spores: sorption characteristics relating to water affinity, glassy states, and storage stability.

    Science.gov (United States)

    Ballesteros, Daniel; Walters, Christina

    2007-01-01

    Ex situ conservation of ferns may be accomplished by maintaining the viability of stored spores for many years. Storage conditions that maximize spore longevity can be inferred from an understanding of the behaviour of water within fern spores. Water sorption properties were measured in spores of five homosporeous species of ferns and compared with properties of pollen, seeds, and fern leaf tissue. Isotherms were constructed at 5, 25, and 45 degrees C and analysed using different physicochemical models in order to quantify chemical affinity and heat (enthalpy) of sorption of water in fern spores. Fern spores hydrate slowly but dry rapidly at ambient relative humidity. Low Brunauer-Emmet-Teller monolayer values, few water-binding sites according to the D'Arcy-Watt model, and limited solute-solvent compatibility according to the Flory-Huggins model suggest that fern spores have low affinity for water. Despite the low water affinity, fern spores demonstrate relatively high values of sorption enthalpy (DeltaH(sorp)). Parameters associated with binding sites and DeltaH(sorp) decrease with increasing temperature, suggesting temperature- and hydration-dependent changes in volume of spore macromolecules. Collectively, these data may relate to the degree to which cellular structures within fern spores are stabilized during drying and cooling. Water sorption properties within fern spores suggest that storage at subfreezing temperatures will give longevities comparable with those achieved with seeds. However, the window of optimum water contents for fern spores is very narrow and much lower than that measured in seeds, making precise manipulation of water content imperative for achieving maximum longevity.

  10. Changes in catchment-scale water fluxes due to time-variant soil hydraulic properties in a subtropical agricultural watershed

    Science.gov (United States)

    Verrot, Lucile; Geris, Josie; Gao, Lei; Peng, Xinhua; Hallett, Paul

    2017-04-01

    In agricultural landscapes, temporal fluxes in hydraulic properties due to tillage, grazing, crop root growth and cycles of wetting and drying influenced by irrigation, could have large impacts at catchment scale. These effects are particularly evident in tropical climates where long periods of drought are followed by intense rainfall that greatly exceeds the infiltration capacity of the soil. This work explores the impact of the seasonal development of crops and the shifts in time between crop types on soil physical properties and the relative changes in the probability distribution of the water storage and fluxes dynamics. We focussed on an agricultural catchment in south east China where the climatic conditions include periods of droughts and heavy rainfall. Using coupled 1-dimension and semi-distributed catchment modelling combined with basic water balance data and both on-site and literature values for soil and crop properties, we investigated the impact of soil physical changes in the root-zone of the soil over different time scales ranging from daily to annual. Our results also showed that the resulting time-variant spatial patterns in soil water storage and flow had an impact on the integrated catchment runoff response at different times of the year.

  11. A molecular dynamics study on surface properties of supercooled water

    Institute of Scientific and Technical Information of China (English)

    L(U) Yongjun; WEI Bingbo

    2006-01-01

    Molecular dynamics simulations were performed to study the surface properties of water in a temperature range from 228 to 293 K by using the extended simple point charge (SPC/E) and four-site TIP4P potentials. The calculated surface tension increases with the decrease of temperature, and moreover the slopes of the surface tension-temperature curves show a weak rise below 273 K, whereas no obvious anomalies appear near 228 K, which accords with the previous experiments. Compared with the measured values, the SPC/E potential shows a good agreement, and the TIP4P potential scription of the surface structure of supercooled water for the SPC/E. When simulating the orientational distributions of water molecules near the surface, the SPC/E potential produces higher ordering and larger surface potentials than the TIP4P potential.

  12. Effective modification of particle surface properties using ultrasonic water mist

    DEFF Research Database (Denmark)

    Genina, Natalja; Räikkönen, Heikki; Heinämäki, Jyrki

    2009-01-01

    The goal of the present study was to design a new technique to modify particle surface properties and, through that, to improve flowability of poorly flowing drug thiamine hydrochloride and pharmaceutical sugar lactose monohydrate of two different grades. The powdered particles were supplied...... properties. It was found that rapid exposition of pharmaceutical materials by water mist resulted in the improvement of powder technical properties. The evident changes in flowability of coarser lactose were obviously due to smoothing of particle surface and decreasing in the level of fines with very slight...... increment in particle size. The changes in thiamine powder flow were mainly due to narrowing in particle size distribution where the tendency for better flow of finer lactose was related to surface and size modifications. The aqueous mist application did not cause any alteration of the crystal structures...

  13. Effective modification of particle surface properties using ultrasonic water mist

    DEFF Research Database (Denmark)

    Genina, Natalja; Räikkönen, Heikki; Heinämäki, Jyrki

    2009-01-01

    increment in particle size. The changes in thiamine powder flow were mainly due to narrowing in particle size distribution where the tendency for better flow of finer lactose was related to surface and size modifications. The aqueous mist application did not cause any alteration of the crystal structures......The goal of the present study was to design a new technique to modify particle surface properties and, through that, to improve flowability of poorly flowing drug thiamine hydrochloride and pharmaceutical sugar lactose monohydrate of two different grades. The powdered particles were supplied...... properties. It was found that rapid exposition of pharmaceutical materials by water mist resulted in the improvement of powder technical properties. The evident changes in flowability of coarser lactose were obviously due to smoothing of particle surface and decreasing in the level of fines with very slight...

  14. Effectiveness of a sediment time critical removal action-PCB reduction in fish tissue, surface water, and sediment via wet excavation.

    Science.gov (United States)

    Santini, Andrew D; King, Todd; Krawczyk, Keith; Kern, John W

    2015-01-01

    Documenting successful remediation of polychlorinated biphenyl (PCB)-contaminated sediments is limited; potentially due to inadequate monitoring methods, complexities associated with the environment, and selected remedial techniques. At some sites, absence of appropriate baseline and postremoval monitoring limits proper evaluation of remedial efficacy. Accurate interpretation of interactions between media, space, time, species, lipid content, and remedial technique requires robust study design and data. This article presents baseline and postremoval data documenting reduced PCB concentrations in fish tissue, surface water, and sediment in response to the US Environmental Protection Agency (USEPA) time-critical removal action (TCRA) that was conducted at the former Bryant Mill Pond (BMP) on Portage Creek in Kalamazoo, Michigan. The BMP is part of an operable unit (OU) within the Allied Paper, Inc./Portage Creek/Kalamazoo River Superfund Site. PCBs discharged to the creek as a byproduct of carbonless copy paper recycling are the primary contaminant of concern. Paper waste residuals commonly appear as gray to light gray clays in river sediments and floodplain soils. The cleanup criterion was 10 mg/kg, with a residual PCB concentration goal of 1 mg/kg. Because the PCB-containing waste is (generally) associated with readily visible light gray clay, excavation of all visibly contaminated current or formerly impounded sediment served as a surrogate for the cleanup criteria and goal. Sediment was wet excavated and backfilled after diversion of the creek. After confirmation that PCB concentrations met cleanup criteria, the stream was diverted to the excavated side, and excavation and backfilling were completed. Overall, 146000 cubic yards of material including PCB-contaminated sediments were removed from the BMP. The long-term monitoring (LTM) program implemented by the Michigan Department of Environmental Quality (MDEQ), and historic data from a variety of sources

  15. Experimental investigation of the link between static and dynamic wetting by forced wetting of nylon filament.

    Science.gov (United States)

    Vega, M J; Gouttière, C; Seveno, D; Blake, T D; Voué, M; De Coninck, J; Clarke, A

    2007-10-09

    Forced wetting experiments with various liquids were conducted to study the dynamic wetting properties of nylon filament. The molecular-kinetic theory of wetting (MKT) was used to interpret the dynamic contact angle data and evaluate the contact-line friction zeta0 at the microscopic scale. By taking account of the viscosity of the liquid, zeta0 could be related exponentially to the reversible work of adhesion. This clearly establishes an experimental link between the static and dynamic wetting properties of the material. Moreover, statistical analysis of the equilibrium molecular displacement frequency K0 and the length of the displacements lambda reveals that these two fundamental parameters of the MKT are strongly correlated, not only in the linearized form of the theory (valid close to equilibrium) but also when the nonlinear form of the equations has to be considered at higher wetting speeds.

  16. Biodegradation of wet-white leather

    OpenAIRE

    Ollé Otero, Lluís; Jorba Rafart, Montse; Font Vallès, Joaquim; Shendrik, Alexander; Bacardit Dalmases, Anna

    2011-01-01

    This paper deals with the study of the physical, chemical and biological processes associated with the deterioration of wet-white leather. The samples of leather were exposed for eight months to outdoor weathering and then their properties were subsequently evaluated. The results indicate that resistance and dimensional stability of wet-white (THPS-syntan) leather is higher than that of chrometanned leather. The comparative work with chrome leather was described earlier.

  17. Effect of Pressure on Wetting Properties of Crude Oil, Sandstone Rock, Water, CO2 and (or) Flue Gas System

    NARCIS (Netherlands)

    Shojaikaveh, N.; Amerighasrodashti, A.; Rossen, W.R.; Bruining, J.; Wolf, K-H.A.A.

    2014-01-01

    Carbon dioxide injection, either miscible or immiscible, has been known as an efficient strategy to enhance oil recovery as well as reduce CO2 emission. Wettability has a significant effect on the performance of enhanced oil recovery techniques because of its effect on fluid saturation distribution

  18. Regulation of Isotopic Composition of Water - way of Improvement of Cosmonauts Drinking Water Functional Properties

    Science.gov (United States)

    Kulikova, Ekaterina; Utina, Dina; Vorozhtsova, Svetlana; Severyuhin, Yuri; Abrosimova, Anna; Sinyak, Yuri; Ivanov, Alexander

    The problem in providing drinking water to cosmonauts is solved - at this moment there is a task to improve the functional properties of the water. One of the perspectives of this trend is the use of light isotopic water. The animal studies have shown that long-term consumption of water with a depletion of deuterium and oxygen heavy isotopes accelerates the rise of mass non-irradiated mice, the phase fluctuations reducing or increasing hematological parameters were having adaptive nature. These fluctuations didn’t overcome values beyond the physiological norm of this type of animal. It is established that the therapeutic use of light isotopic water with 35 - 90 ppm in deuterium increases the survival of irradiated mice by an average of 30%, contributes to the preservation of irradiated animals body weight. Treatment of acute radiation sickness with light isotopic water stimulates hematopoietic recovery. At the same time, keeping mice drinking light isotopic water for 7 - 8 days before the irradiation (from 4 to 8.5 Gr) has no effect on the level of radio resistance. Longer keeping mice on light isotopic water, for 14 -21 days - reduction in life expectancy, animal mass, bone marrow cellularity and the level of white blood cells in irradiated animals is noted. It was established that keeping mice on light isotopic water for 14 days before exposure in experimental animals causes an increase in the mitotic index and the frequency of formation of aberrant mitosis after 24 hours of Co(60) gamma radiation in doses of 1 , 2, and 4 Gr. Thus, it is clear that the regulation of the isotopic composition of drinking water - way to improve its functional properties.

  19. Spatial patterns of wetting characteristics in grassland sandy soil

    Directory of Open Access Journals (Sweden)

    Orfánus Tomáš

    2016-06-01

    Full Text Available In grasslands where organic and inorganic resources are alternating at scales of individual plants, the transient character is given to certain wetting properties of soil, which then become highly variable both in space and in time. The objective of presented study was to study wetting pattern within two soil horizons at 5-cm and 10-cm depths respectively and to examine how the wetting patterns relate to hydraulic conductivity determined by Minidisc infiltrometer at suction −2 cm, K(−2 cm. This characteristics is implicitly independent on antecedent soil water content (SWC since it relates to steady infiltration phase but can be influenced by present soil water repellency (SWR. Field measurements were performed on July 27–28, 2010 on the grassland experimental site located near the village Sekule in Southwest Slovakia. The water drop penetration time (WDPT, SWC and tension Minidisc infiltration measurements were carried out on the 0.64 m2 plot in a regular 8 × 8 grid. The results showed that SWR and SWC influence each other and cause correlation between spatial patterns of studied soil wetting characteristics and between characteristics measured at the two soil depths. Further, it was found out, that calculation of K(−2 cm according to Zhang may cause apparent correlation of K(−2 cm with antecedent SWC, which is the artificial effect of sorptivity parameter in the equation on steady stage of infiltration process. This pseudocorrelation has disappeared after adopting of Minasny and McBratney (2000 approaches by calculation of K(−2 cm.

  20. A review of ethanol wet-bonding: Principles and techniques.

    Science.gov (United States)

    Ayar, Muhammet Kerim

    2016-01-01

    Conventional water wet-bonding technique has been advocated by many scientists, but the excess water will induce suboptimal polymerization of dental adhesives, phase separation, and nanoleakage, which will influence the longevity of resin-dentin interfaces. Recent studies have put forward a new concept, ethanol wet-bonding. This technique can increase in dentin bond durability. This review focuses on the principles of ethanol wet-bonding, its surface treatment methods.

  1. A review of ethanol wet-bonding: Principles and techniques

    OpenAIRE

    Ayar, Muhammet Kerim

    2016-01-01

    Conventional water wet-bonding technique has been advocated by many scientists, but the excess water will induce suboptimal polymerization of dental adhesives, phase separation, and nanoleakage, which will influence the longevity of resin-dentin interfaces. Recent studies have put forward a new concept, ethanol wet-bonding. This technique can increase in dentin bond durability. This review focuses on the principles of ethanol wet-bonding, its surface treatment methods.

  2. Thickness of residual wetting film in liquid-liquid displacement

    Science.gov (United States)

    Beresnev, Igor; Gaul, William; Vigil, R. Dennis

    2011-08-01

    Core-annular flow is common in nature, representing, for example, how streams of oil, surrounded by water, move in petroleum reservoirs. Oil, typically a nonwetting fluid, tends to occupy the middle (core) part of a channel, while water forms a surrounding wall-wetting film. What is the thickness of the wetting film? A classic theory has been in existence for nearly 50 years offering a solution, although in a controversial manner, for moving gas bubbles. On the other hand, an acceptable, experimentally verified theory for a body of one liquid flowing in another has not been available. Here we develop a hydrodynamic, testable theory providing an explicit relationship between the thickness of the wetting film and fluid properties for a blob of one fluid moving in another, with neither phase being gas. In its relationship to the capillary number Ca, the thickness of the film is predicted to be proportional to Ca2 at lower Ca and to level off at a constant value of ˜20% the channel radius at higher Ca. The thickness of the film is deduced to be approximately unaffected by the viscosity ratio of the fluids. We have conducted our own laboratory experiments and compiled experimental data from other studies, all of which are mutually consistent and confirm the salient features of the theory. At the same time, the classic law, originally deduced for films surrounding moving gas bubbles but often believed to hold for liquids as well, fails to explain the observations.

  3. Fast and Slow Wetting Dynamics on nanostructured surfaces

    Science.gov (United States)

    Nandyala, Dhiraj; Rahmani, Amir; Cubaud, Thomas; Colosqui, Carlos

    2015-11-01

    This talk will present force-displacement and spontaneous drop spreading measurements on diverse nanostructured surfaces (e.g., mesoporous titania thin films, nanoscale pillared structures, on silica or glass substrates). Experimental measurements are performed for water-air and water-oil systems. The dynamics of wetting observed in these experiments can present remarkable crossovers from fast to slow or arrested dynamics. The emergence of a slow wetting regime is attributed to a multiplicity of metastable equilibrium states induced by nanoscale surface features. The crossover point can be dramatically advanced or delayed by adjusting specific physical parameters (e.g., viscosity of the wetting phases) and geometric properties of the surface nanostructure (e.g., nanopore/pillar radius and separation). Controlling the crossover point to arrested dynamics can effectively modify the degree of contact angle hysteresis and magnitude of liquid adhesion forces observed on surfaces of different materials. This work is supported by a SEED Award from The Office of Brookhaven National Laboratory Affairs at Stony Brook University.

  4. Wet Work and Barrier Function.

    Science.gov (United States)

    Fartasch, Manigé

    2016-01-01

    Wet work defined as unprotected exposure to humid environments/water; high frequencies of hand washing procedures or prolonged glove occlusion is believed to cause irritant contact dermatitis in a variety of occupations. This review considers the recent studies on wet-work exposure and focuses on its influence on barrier function. There are different methods to study the effect of wet work on barrier function. On the one hand, occupational cohorts at risk can be monitored prospectively by skin bioengineering technology and clinical visual scoring systems; on the other hand, experimental test procedures with defined application of water, occlusion and detergents are performed in healthy volunteers. Both epidemiological studies and the results of experimental procedures are compared and discussed. A variety of epidemiological studies analyze occupational cohorts at risk. The measurement of transepidermal water loss, an indicator of the integrity of the epidermal barrier, and clinical inspection of the skin have shown that especially the frequencies of hand washing and water contact/contact to aqueous mixtures seem to be the main factors for the occurrence of barrier alterations. On the other hand, in a single cross-sectional study, prolonged glove wearing (e.g. occlusion for 6 h per shift in clean-room workers) without exposure to additional hazardous substances seemed not to affect the skin negatively. But regarding the effect of occlusion, there is experimental evidence that previously occluded skin challenged with sodium lauryl sulfate leads to an increased susceptibility to the irritant with an aggravation of the irritant reaction. These findings might have relevance for the real-life situation in so far as after occupational glove wearing, the skin is more susceptible to potential hazards to the skin even during leisure hours.

  5. A new low-cost method of reclaiming mixed foundry waste sand based on wet-thermal composite reclamation

    Institute of Scientific and Technical Information of China (English)

    Fan Zitian; Liu Fuchu; Long Wei; Li Guona

    2014-01-01

    A lot of mixed clay-resin waste sand from large-scale iron foundries is discharged every day; so mixed waste sand reclamation in low cost and high quality has a great realistic significance. In the study to investigate the possibility of reusing two types of waste foundry sands, resin bonded sand and clay bonded sand which came from a Chinese casting factory, a new low-cost reclamation method of the mixed foundry waste sand based on the wet-thermal composite reclamation was proposed. The waste resin bonded sand was first reclaimed by a thermal method and the waste clay bonded sand was reclaimed by a wet method. Then, hot thermal reclaimed sand and the dehydrated wet reclaimed sand were mixed in certain proportions so that the hot thermal reclaimed sand dried the wet reclaimed sand leaving some water. The thermal reclamation efficiency of the waste resin bonded sand was researched at different heat levels. The optimized wet reclamation process of the waste clay bonded sand was achieved by investigating the effects of wet reclamation times, sand-water ratio and pH value on the reclaimed sand characteristics. The composite reclamation cost also was calculated. The research results showed that the properties of the mixed reclaimed sand can satisfy the application requirements of foundries; in which the temperature of the thermal reclamation waste resin bonded sand needs to be about 800 ºC, the number of cycles of wet reclamation waste clay bonded sand should reach four to five, the optimal sand-water ratio of wet reclamation is around 1:1.5, and the pH value should be adjusted by adding acid. The mass ratio of hot thermal reclaimed sand to dehydrated wet reclaimed sand is about 1:2.5, and the composite reclaimed sand cost is around 100 yuan RMB per ton.

  6. A new low-cost method of reclaiming mixed foundry waste sand based on wet-thermal composite reclamation

    Directory of Open Access Journals (Sweden)

    Fan Zitian

    2014-09-01

    Full Text Available A lot of mixed clay-resin waste sand from large-scale iron foundries is discharged every day; so mixed waste sand reclamation in low cost and high quality has a great realistic significance. In the study to investigate the possibility of reusing two types of waste foundry sands, resin bonded sand and clay bonded sand which came from a Chinese casting factory, a new low-cost reclamation method of the mixed foundry waste sand based on the wet-thermal composite reclamation was proposed. The waste resin bonded sand was first reclaimed by a thermal method and the waste clay bonded sand was reclaimed by a wet method. Then, hot thermal reclaimed sand and the dehydrated wet reclaimed sand were mixed in certain proportions so that the hot thermal reclaimed sand dried the wet reclaimed sand leaving some water. The thermal reclamation efficiency of the waste resin bonded sand was researched at different heat levels. The optimized wet reclamation process of the waste clay bonded sand was achieved by investigating the effects of wet reclamation times, sand-water ratio and pH value on the reclaimed sand characteristics. The composite reclamation cost also was calculated. The research results showed that the properties of the mixed reclaimed sand can satisfy the application requirements of foundries; in which the temperature of the thermal reclamation waste resin bonded sand needs to be about 800 篊, the number of cycles of wet reclamation waste clay bonded sand should reach four to five, the optimal sand-water ratio of wet reclamation is around 1:1.5, and the pH value should be adjusted by adding acid. The mass ratio of hot thermal reclaimed sand to dehydrated wet reclaimed sand is about 1:2.5, and the composite reclaimed sand cost is around 100 yuan RMB per ton.

  7. The role of water on the structure and mechanical properties of a thermoplastic natural block co-polymer from squid sucker ring teeth.

    Science.gov (United States)

    Rieu, Clément; Bertinetti, Luca; Schuetz, Roman; Salinas-Zavala, Cesar Ca; Weaver, James C; Fratzl, Peter; Miserez, Ali; Masic, Admir

    2016-09-02

    Hard biological polymers exhibiting a truly thermoplastic behavior that can maintain their structural properties after processing are extremely rare and highly desirable for use in advanced technological applications such as 3D-printing, biodegradable plastics and robust composites. One exception are the thermoplastic proteins that comprise the sucker ring teeth (SRT) of the Humboldt jumbo squid (Dosidicus gigas). In this work, we explore the mechanical properties of reconstituted SRT proteins and demonstrate that the material can be re-shaped by simple processing in water and at relatively low temperature (below 100 °C). The post-processed material maintains a high modulus in the GPa range, both in the dry and the wet states. When transitioning from low to high humidity, the material properties change from brittle to ductile with an increase in plastic deformation, where water acts as a plasticizer. Using synchrotron x-ray scattering tools, we found that water mostly influences nano scale structure, whereas at the molecular level, the protein structure remains largely unaffected. Furthermore, through simultaneous in situ x-ray scattering and mechanical tests, we show that the supramolecular network of the reconstituted SRT material exhibits a progressive alignment along the strain direction, which is attributed to chain alignment of the amorphous domains of SRT proteins. The high modulus in both dry and wet states, combined with their efficient thermal processing characteristics, make the SRT proteins promising substitutes for applications traditionally reserved for petroleum-based thermoplastics.

  8. Effect of wet-chemical substrate pretreatment on electronic interface properties and recombination losses of a -Si:H/c -Si and a -SiN{sub x}:H/c -Si hetero-interfaces

    Energy Technology Data Exchange (ETDEWEB)

    Angermann, Heike; Conrad, Erhard; Korte, Lars; Schmidt, Manfred [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Institut fuer Silizium-Photovoltaik, Berlin (Germany); Wuensch, Frank; Kunst, Marinus [Helmholtz-Zentrum Berlin fuer Materialien und Energie GmbH, Institut Solare Brennstoffe und Energiespeichermaterialien, Berlin (Germany); Laades, Abdelazize; Stuerzebecher, Uta [CiS Institut fuer Mikrosensorik GmbH, SolarZentrum Erfurt (Germany)

    2011-03-15

    Surface charge, surface state density and interface recombination behavior on polished float zone (FZ) solar cell substrates were investigated after various wet-chemical pre-cleaning procedures and deposition of amorphous silicon (a-Si:H) or silicon nitride (a-SiNx:H). Applying surface photo voltage (SPV), microwave detected photo conductance decay ({mu}W-PCD) and transient microwave conduction (TRMC) measurements, electronic interface properties were monitored repeatedly during the preparation processes. As shown for an inverted a-Si:H/c-Si hetero-junction structure, with front side passivation by a-SiN{sub x}:H and a p-type a-Si:H emitter on the rear side, the effect of optimised wet-chemical pre-treatment can be preserved during the subsequent soft plasma enhanced chemical vapour deposition of a-Si:H or a-SiN{sub x}:H. This leads to hetero-interfaces with low interface recombination velocities. These results were compared to previously reported findings, obtained on textured Czochralski (CZ) single crystalline substrates. a-SiN{sub x}:H is known to result in a field effect passivation. Nevertheless a strong influence of wet-chemical treatments on surface charge and recombination losses was observed on both flat and textured a-SiN{sub x}:H/c-Si interfaces. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  9. Mold management of wetted carpet.

    Science.gov (United States)

    Ong, Kee-Hean; Dixit, Anupma; Lewis, Roger D; MacDonald Perkins, Maureen; Backer, Denis; Condoor, Sridhar; Emo, Brett; Yang, Mingan

    2014-01-01

    This study evaluated the growth and removal of fungi on wetted carpet using newly designed technologies that rely on physical principles of steam, heat, and fluid flow. Sixty samples of carpet were embedded with heat-treated house dust, followed by embedding, wearing with a hexapod, and wetting. Samples were inoculated using a liquid suspension of Cladosporium sphaerospermum prior to placement over a water-saturated foam pad. Incubation times were 24 hr, 7 days, and 30 days. Cleaning was performed using three methods; high-flow hot water extraction, hot water and detergent, and steam. Fungal loading increased from approximately 1500 colony forming units per area (CFU/cm(2)) in 24 hr to a maximum of approximately 10,200 CFU/cm(2) after 7 days with a slight decline to 9700 CFU/cm(2) after 30 days incubation. Statistically significant differences were found among all three methods for removal of fungi for all three time periods (p Steam-vapor was significantly better than the alternative methods (p steam has a consistent fungal removal rate, the detergent and high-flow, hot water methods decline in efficiency with increasing incubation time.

  10. Influence of pH on wetting kinetics of a pine forest soil

    Science.gov (United States)

    Amer, Ahmad; Schaumann, Gabriele; Diehl, Dörte

    2014-05-01

    Water repellent properties of organic matter significantly alter soil water dynamics. Various environmental factors control appearance and breakup of repellency in soil. Beside water content and temperature also pH exerts an influence on soil water repellency although investigations achieved partly ambiguous results; some found increasing repellency with increasing pH (Terashima et al. 2004; Duval et al. 2005), other with decreasing pH (Karnok et al. 1993; Roper 2005) and some found repellency maxima at intermediate pH and an increase with decreasing and with increasing pH (Bayer and Schaumann 2007; Diehl et al. 2010). The breakup of repellency may be observed via the time dependent sessile drop contact angle (TISED). With water contact time, soil-water contact angle decreases until complete wetting is reached. Diehl and Schaumann (2007) calculated the activation energy of the wetting process from the rate of sessile drop wetting obtained at different temperatures and draw conclusions on chemical or physical nature of repellency. The present study aims at the influence of pH on the wetting kinetics of soil. Therefore, TISED of soil was determined as a function of pH and temperature. We used upper soil samples (0 - 10 cm) from a pine forest in the southwest of Germany (Rheinland-Pfalz). Samples were air-dried, sieved Contact Angle Meter (Dataphysics, Germany) on three replications for each soil sample. Apparent work of adhesion was calculated, plotted vs. time and mathematically fitted using double exponential function. Rate constants of wetting were used to determine the activation energy by Arrhenius equation. First results indicated that despite comparable initial contact angles, pH alteration strongly changed the wetting rate suggesting maximum wetting resistance at the natural pH of 4.3 and decreasing wetting resistance at lower and at higher pH. The poster will present further current results of the ongoing study and discuss the activation energy of the

  11. Wetting, superhydrophobicity, and icephobicity in biomimetic composite materials

    Science.gov (United States)

    Hejazi, Vahid

    Recent developments in nano- and bio-technology require new materials. Among these new classes of materials which have emerged in the recent years are biomimetic materials, which mimic structure and properties of materials found in living nature. There are a large number of biological objects including bacteria, animals and plants with properties of interest for engineers. Among these properties is the ability of the lotus leaf and other natural materials to repel water, which has inspired researchers to prepare similar surfaces. The Lotus effect involving roughness-induced superhydrophobicity is a way to design nonwetting, self-cleaning, omniphobic, icephobic, and antifouling surfaces. The range of actual and potential applications of superhydrophobic surfaces is diverse including optical, building and architecture, textiles, solar panels, lab-on-a-chip, microfluidic devices, and applications requiring antifouling from biological and organic contaminants. In this thesis, in chapter one, we introduce the general concepts and definitions regarding the wetting properties of the surfaces. In chapter two, we develop novel models and conduct experiments on wetting of composite materials. To design sustainable superhydrophobic metal matrix composite (MMC) surfaces, we suggest using hydrophobic reinforcement in the bulk of the material, rather than only at its surface. We experimentally study the wetting properties of graphite-reinforced Al- and Cu-based composites and conclude that the Cu-based MMCs have the potential to be used in the future for the applications where the wear-resistant superhydrophobicity is required. In chapter three, we introduce hydrophobic coating at the surface of concrete materials making them waterproof to prevent material failure, because concretes and ceramics cannot stop water from seeping through them and forming cracks. We create water-repellant concretes with CA close to 160o using superhydrophobic coating. In chapter four, experimental

  12. Airborne Demonstration of Microwave and Wide-Band Millimeter-Wave Radiometers to Provide High-Resolution Wet-Tropospheric Path Delay Corrections for Coastal and Inland Water Altimetry

    Science.gov (United States)

    Reising, Steven; Kangaslahti, Pekka; Tanner, Alan; Padmanabhan, Sharmila; Montes, Oliver; Parashare, Chaitali; Bosch-Lluis, Xavier; Hadel, Victoria; Johnson, Thaddeus; Brown, Shannon; Khayatian, Behrouz; Dawson, Douglas; Gaier, Todd; Razavi, Behzad

    2014-05-01

    Current satellite ocean altimeters include nadir-viewing, co-located 18-34 GHz microwave radiometers to measure wet-tropospheric path delay. Due to the size of the surface instantaneous fields of view (IFOV) at these frequencies, the accuracy of wet path retrievals is substantially degraded near coastlines, and retrievals are not provided over land. Retrievals are flagged as not useful within approximately 40 km of the world's coastlines. A viable approach to improve their capability is to add wide-band high-frequency millimeter-wave window channels in the 90-180 GHz band, thereby achieving finer spatial resolution for a limited antenna size. In this context, the upcoming NASA/CNES/CSA Surface Water and Ocean Topography (SWOT) mission is in formulation and planned for launch in late 2020. The primary objectives of SWOT are to characterize ocean mesoscale and sub-mesoscale processes on 10-km and larger scales in the global oceans and provide measurements of the global water storage in inland surface water bodies and the flow rate of rivers. Therefore, an important new science objective of SWOT is to transition satellite altimetry from the open ocean into the coastal zone and over inland water. The addition of 90-180 GHz millimeter-wave window-channel radiometers to current Jason-class 18-34 GHz radiometers is expected to improve retrievals of wet-tropospheric delay in coastal areas and to enhance the potential for over-land retrievals. In 2012 the Ocean Surface Topography Science Team Meeting recommended to add high-frequency millimeter-wave radiometers to the Jason Continuity of Service (CS) mission. To reduce the risks of wet-tropospheric path delay measurement over coastal areas and inland water bodies, we have designed, developed and fabricated a new airborne radiometer, combining three high-frequency millimeter-wave window channels at 90, 130 and 168 GHz, along with Jason-series microwave channels at 18.7, 23.8 and 34.0 GHz, and validation channels sounding

  13. Adsorption and wetting.

    NARCIS (Netherlands)

    Schlangen, L.J.M.

    1995-01-01

    Adsorption and wetting are related phenomena. In order to improve knowledge of both and their relations, experiments, thermodynamics and a theoretical interpretation have been connected, starring n-alkanes.Starting from the Gibbs adsorption equation thermodynamic relations between vapour adsorption

  14. Novel applications of biomass wet pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Sillanpaa, M. [Lappeenranta Univ. of Technology (Finland)], email: mika.sillanpaa@lut.fi

    2012-07-01

    Production of carbonaceous material from unconventional wet biomass sources by thermal processing offers interesting novel opportunities and application possibilities in different fields. Thermal treatment at low temperatures refers to torrefication in general. Disadvantage in this technique is that biomass has to be dried first which consumes a lot energy and time and limits use of biomass materials widely. In wetpyrolysis (hydrothermal carbonization, HTC), biomass source can be wetter, like wood, household wastes, manure or industrial wastewater sludge. Reaction takes place in water environment at higher temperature (180-250 deg C) and pressure which is self-generated. Typically reaction system is high pressure reactor also called autoclave. Comparing to torrefaction HTC produces more solid yield, water soluble organic compounds but formation is low during reaction. Properties of the product can be easily modified by changing reaction conditions, utilization of additives or catalysts. Novel materials obtained by this technique will be used in different applications in water treatment and it will be also interesting to compare purification efficiency of these materials to activated carbon.

  15. Induced heterogeneity of soil water content and chemical properties by treated wastewater irrigation and its reclamation by freshwater irrigation

    Science.gov (United States)

    Rahav, Matan; Brindt, Naaran; Yermiyahu, Uri; Wallach, Rony

    2017-06-01

    The recognition of treated wastewater (TWW) as an alternative water resource is expanding in areas with a shortage of freshwater (FW) resources. Today, most orchards in Israel are irrigated with TWW. While the benefits of using TWW for irrigation are apparent, evidence of its negative effects on soil, trees, and yield is accumulating. This study, performed in a commercial TWW-irrigated citrus orchard in central Israel, examined the effects of (1) soil-wettability decrease due to prolonged TWW irrigation on the spatial and temporal distribution of water content and associated chemical properties in the root zone; (2) the conversion of irrigation in half of the TWW-irrigated research plot to FW (2012) for soil reclamation. Electrical resistivity tomography surveys in the substantially water repellent soils revealed that water flow is occurring along preferential flow paths in both plots, leaving behind a considerably nonuniform water-content distribution. This was despite the gradual relief in soil water repellency measured in the FW plots. Four soil-sampling campaigns (spring and fall, 2014-2016), performed in 0-20 and 20-40 cm layers of the research plot, revealed bimodal gravimetrically measured water-content distribution. The preferential flow led to uneven chemical-property distribution, with substantially high concentrations in the dry spots, and lower concentrations in the wet spots along the preferential flow paths. The average salt and nutrient concentrations, which were initially high in both plots, gradually dispersed with time, as concentrations in the FW plots decreased. Nevertheless, the efficiency of reclaiming TWW soil by FW irrigation appears low.

  16. Wet hydrate dissolution plant

    OpenAIRE

    Stanković Mirjana S.; Kovačević Branimir T.; Pezo Lato L.

    2003-01-01

    The IGPC Engineering Department designed basic projects for a wet hydrate dissolution plant, using technology developed in the IGPC laboratories. Several projects were completed: technological, machine, electrical, automation. On the basis of these projects, a production plant with capacity of 50,000 t/y was manufactured, at "Zeolite Mira", Mira (VE), Italy, in 1997, for increasing detergent zeolite production from 50,000 to 100,000 t/y. Several goals were realized by designing a wet hydrate ...

  17. Thermodynamic properties of water desorption of forage turnip seeds

    Directory of Open Access Journals (Sweden)

    Kelly Aparecida Sousa

    2014-11-01

    Full Text Available The purpose of this study was to determine the thermodynamic properties of the process of water sorption in forage turnip  seeds. The equilibrium moisture content of forage turnip  seeds was determined by the gravimetric-dynamic method for different values of temperature and water activity. According to the results, increasing the moisture content increases the energy required for the evaporation of water in forage turnip seeds, and the values of integral isosteric heat of desorption, within the moisture content range of 3.33 to 11.30 (% d.b., varies from 4,222.70 to 2,870.34 kJ kg-1. With the elevation in the equilibrium moisture content, there is an increase in differential entropy and Gibbs free energy, which has positive values, demonstrating non-spontaneity in the process of desorption in the seeds. The theory of enthalpy-entropy compensation can be satisfactorily applied to the sorption phenomenon, and the process of water desorption of forage turnip seeds is controlled by enthalpy.

  18. Fouling-release Property of Water-filled Porous Elastomers

    Institute of Scientific and Technical Information of China (English)

    Lai-yong Xie; Fei Hong; Chuan-xin He; Jian-hong Liu; Chi Wu

    2012-01-01

    Since the fouling-releasing ability of silicone elastomers increased as their modulus decreases,we designed and prepared composites with embedded tiny NaCl crytals that were soluble after their immersion in water,resulting in water-filled porous elastomers.The scanning electron microscope images confirmed such a designed water-filling porous structure.The existence of many micro-drops of water in these specially designed elastomers decreased the shear storage modulus and increased the loss factors.The decrease of shear modulus plays a leading role here and is directly related to a lower critical peeling-off stress of a pseudo-barnacle on them.Therefore,such a novel preparation with cheap salts instead of an expensive silicone provides a better way to make fouling-release paints with a lower modulus,a lower critical peeling-off stress and a better fouling-release property without a significant decrease of the cross-linking density.

  19. [Mutagen properties of water-soluble polysaccharides from Acorus calamus].

    Science.gov (United States)

    Gur'ev, A M; Belousov, M B; Akhmedzhanov, R R; Iusubov, M S; Voronova, O L; Karpova, G V; Churin, A A

    2010-08-01

    Mutagenic properties of water soluble polysaccharides (WSPS) extracted from Acorus calamus L. have been studied. Neither a single intravenous injection nor a course intraperitoneal introduction of WSPS in a dose of 1/2 LD50 to mice of the CBA/CaLac line increases the level of cytogenetic disorders in the bone marrow cells. The investigation of WSPS by means of the somatic mosaicism test showed that the given dose of WSPS does not increase the rate of mutant spots on Drosophila wings.

  20. Preparation and Properties of Water-soluble Conjugated Polyelectrolyte

    Institute of Scientific and Technical Information of China (English)

    BAO Xiangjun; HONG Ruibin; HU Jianhua; ZHONG Yiping; LIU Ping; DENG Wenji

    2014-01-01

    The water-soluble conjugated polyelectrolyte, poly[3-(1′-ethyloxy-2′-N- methylimidazole) thiophene] (PEOIMT), was prepared. Its photophysical and electrochemical properties, and response characteristics to the external condition (e g, temperature response, solvent response and pH response), were investigated. The results show the PEOIMT belongs to the organic semiconductor. The interaction between the PEOIMT and the bovine serum albumin (BSA) was investigated using UV-vis spectroscopy. It was found that the PEOIMT could interact with the BSA. The PEOIMT can be used as a biosensor to detect the BSA.

  1. Wetting of flexible fibre arrays.

    Science.gov (United States)

    Duprat, C; Protière, S; Beebe, A Y; Stone, H A

    2012-02-23

    Fibrous media are functional and versatile materials, as demonstrated by their ubiquity both in natural systems such as feathers and adhesive pads and in engineered systems from nanotextured surfaces to textile products, where they offer benefits in filtration, insulation, wetting and colouring. The elasticity and high aspect ratios of the fibres allow deformation under capillary forces, which cause mechanical damage, matting self-assembly or colour changes, with many industrial and ecological consequences. Attempts to understand these systems have mostly focused on the wetting of rigid fibres or on elastocapillary effects in planar geometries and on a fibre brush withdrawn from an infinite bath. Here we consider the frequently encountered case of a liquid drop deposited on a flexible fibre array and show that flexibility, fibre geometry and drop volume are the crucial parameters that are necessary to understand the various observations referred to above. We identify the conditions required for a drop to remain compact with minimal spreading or to cause a pair of elastic fibres to coalesce. We find that there is a critical volume of liquid, and, hence, a critical drop size, above which this coalescence does not occur. We also identify a drop size that maximizes liquid capture. For both wetting and deformation of the substrates, we present rules that are deduced from the geometric and material properties of the fibres and the volume of the drop. These ideas are applicable to a wide range of fibrous materials, as we illustrate with examples for feathers, beetle tarsi, sprays and microfabricated systems.

  2. Mechanical properties and solubility in water of corn starch-collagen composite films: Effect of starch type and concentrations.

    Science.gov (United States)

    Wang, Kun; Wang, Wenhang; Ye, Ran; Liu, Anjun; Xiao, Jingdong; Liu, Yaowei; Zhao, Yana

    2017-02-01

    This study investigated the possibility of enhancing the properties of collagen with three different maize starches: waxy maize starch, normal starch, and high amylose starch. Scanning electron microscopy images revealed that starch-collagen films had a rougher surface compared to pure collagen films which became smoother upon heating. Amylose starch and normal starch increased the tensile strength of unheated collagen films in both dry and wet states, while all starches increased tensile strength of collagen film by heating. Depending upon the amylose content and starch concentrations, film solubility in water decreased with the addition of starch. DSC thermograms demonstrated that addition of all starches improved the thermal stability of the collagen film. Moreover, X-ray diffraction results indicated that except for high amylose starch, the crystallinity of both starch and collagen was significantly decreased when subject to heating. FTIR spectra indicated that intermolecular interactions between starch and collagen were enhanced upon heating.

  3. Membrane-based wet electrostatic precipitation.

    Science.gov (United States)

    Bayless, David J; Shi, Liming; Kremer, Gregory; Stuart, Ben J; Reynolds, James; Caine, John

    2005-06-01

    Emissions of fine particulate matter, PM2.5, in both primary and secondary form, are difficult to capture in typical dry electrostatic precipitators (ESPs). Wet (or water-based) ESPs are well suited for collection of acid aerosols and fine particulates because of greater corona power and virtually no re-entrainment. However, field disruptions because of spraying (misting) of water, formation of dry spots (channeling), and collector surface corrosion limit the applicability of current wet ESPs in the control of secondary PM2.5. Researchers at Ohio University have patented novel membrane collection surfaces to address these problems. Water-based cleaning in membrane collectors made of corrosion-resistant fibers is facilitated by capillary action between the fibers, maintaining an even distribution of water. This paper presents collection efficiency results of lab-scale and pilot-scale testing at FirstEnergy's Bruce Mansfield Plant for the membrane-based wet ESP. The data indicate that a membrane wet ESP was more effective at collecting fine particulates, acid aerosols, and oxidized mercury than the metal-plate wet ESP, even with approximately 15% less collecting area.

  4. Properties and application of wet rubbing fastness improver assisted by copper particles%铜颗粒增效湿摩擦牢度提升剂的性能及其应用

    Institute of Scientific and Technical Information of China (English)

    杨宏林; 项伟; 董淑秀

    2016-01-01

    为提高活性染料深色织物湿摩擦牢度,在丙烯酸丁酯、甲基丙烯酸甲酯及十二烷基苯磺酸钠水溶液混合体系中制备了铜颗粒增效湿摩擦牢度提升剂。使用扫描电子显微镜对其形貌进行表征,测试其粒径,研究了其作为湿摩擦牢度提升剂对活性染料染色棉织物的最佳整理工艺及应用性能。结果表明:铜颗粒增效湿摩擦牢度提升剂的平均粒径为2472 nm,改性铜微粒在水溶液中呈石榴状聚集。浸轧法的最佳整理工艺为:湿摩擦牢度提升剂质量浓度20 g/L,pH值5~6,焙烘温度110~120℃,焙烘时间2 min。当活性染料用量分别为6%、8%(o. w. f)时,经铜颗粒增效湿摩擦牢度提升剂整理后活性染料染色棉织物的耐摩擦色牢度提高1~1�5级。%In order to improve the wet rubbing fastness of fabrics in dark shade, the wet rubbing fastness improver assisted by copper particles was synthesized from butyl acrylate, methyl methacrylate and sodium dodecyl benzene sulfonate. Morphology and dispersion distribution of the wet rubbing fastness improver assisted by copper particles was analyzed by scanning electron microscopy and particle size analysis. It was found that the modified copper particles were assembled like a pomegranate in water. Mean particle diameter of the wet rubbing fastness improver assisted by copper particles is around 2 472 nm. Thus, the finishing processes and application of the wet rubbing fastness improver on cotton fabrics dyed with reactive dyes were investigated. It was found that the optimal finishing process was:the wet rubbing fastness improver mass concentration 20 g/L, pH value 5 -6, baking temperature 110 -120 ℃, baking time 2 min, and padding method. The wet rubbing fastness of cotton fabrics dyed with reactive dyes increased by 1 -1. 5 grades after treatment with wet rubbing fastness improver, when reactive dyes concentration was at 6% and 8%( o. w. f

  5. The world of water, or testing neoliberalism: Is water a common good or private property?

    Directory of Open Access Journals (Sweden)

    Lošonc Alpar

    2006-01-01

    Full Text Available The backbone of neoliberalisation is privatization of common goods from the perspective of market naturalization and creation of a specific resource regime. It is of important to emphasis that neoliberalism coexists with other societal projects and we are witnessing simultaneity amongst different projects. The naturalization of market structures and identification of market with competition produce intensified risk-related consequences for the society; actually, neoliberalism exposes the society to environmental risks with a number of concrete examples. The author analyses the importance of water resources from the economic perspective, especially with regard to the neoliberal perspectives on water resources. The modalities of market-based usage of water are presented, constituting the property-rights regime. It is argued that an unconditional, socially irresponsible privatization does not take into account community-related management of common pools and dogmatically acknowledges only state and private forms of property. Such a critical view is supported with considerations that a the ongoing form of economic globalization does not maintain the development of the green market b water is a common good embedded in cultural and political relationships and filled with symbolic meanings. The impasse concerning the status of water takes place in the context where the Washington-consensus proved to be defective. At the same there is no other coherently formulated corpus of ideas to substitute the neoliberal canon. Water as a common good needs normative engagement and ecological economy has a task to participate in determination of sustainable levels of costs and prices of water resources.

  6. Water Repellency, Infiltration and Water Retention Properties of Forest Soils Under Different Management Practices

    Science.gov (United States)

    Wahl, N. A.; Bens, O.; Schäfer, B.; Hüttl, R. F.

    For soils under both agricultural and forest use, management and tillage practice can have significant influence on the hydraulic properties. It is therefore supposed, that management practices are capable of altering surface runoff, water retention and flood- ing risk for river catchments. Soil water repellency (hydrophobicity) can adversely affect soil hydrological properties, e.g. reduce infiltration capacity and induce pref- erential flow, thus enhancing the overall risk of flooding in river catchment areas. Hydrophobic effects are especially pronounced in coniferous forest soils. Investigations were carried out on several study plots in the German Northeastern Lowlands, located app. 50 km NE of Berlin in Brandenburg. Soils found in the area are mainly of glacifluvial origin with a pronounced sandy texture (with medium sized sand dominating). The four stands investigated represent different stages of forest transfor- mation, in a sense of a SfalseT chronosequence and are made up of populations of & cedil;Pinus sylvestris and Fagus sylvatica of different ages. Infiltration was measured with hood infiltrometers, and single infiltration rings at soil surface. Water retention capacity and the influence of soil organic matter on water storage were evaluated with laboratory methods. Water repellency was quantified with the water drop penetration time (WDPT) test, for determining the persistence of water repellency, and the ethanol percentage (EP) test, for measuring the severity/degree of water repellency. Soil samples from the four forest plots and different soil depths (0U160 cm) were used for the measurements. SPotentialT water repellencies were & cedil;determined after 3-day oven-drying at 45 C. The results indicate that for sandy forest soils, the overall infiltration capacity of the plots is low due to the effects of water repellency. The inter-variability of the plots is mainly caused by changes in the textural composition of the soils. For all plots a

  7. The Role of Surface Chemistry in Adhesion and Wetting of Gecko Toe Pads

    Science.gov (United States)

    Badge, Ila; Stark, Alyssa Y.; Paoloni, Eva L.; Niewiarowski, Peter H.; Dhinojwala, Ali

    2014-10-01

    An array of micron-sized setal hairs offers geckos a unique ability to walk on vertical surfaces using van der Waals interactions. Although many studies have focused on the role of surface morphology of the hairs, very little is known about the role of surface chemistry on wetting and adhesion. We expect that both surface chemistry and morphology are important, not only to achieve optimum dry adhesion but also for increased efficiency in self-cleaning of water and adhesion under wet conditions. Here, we used a plasma-based vapor deposition process to coat the hairy patterns on gecko toe pad sheds with polar and non-polar coatings without significantly perturbing the setal morphology. By a comparison of wetting across treatments, we show that the intrinsic surface of gecko setae has a water contact angle between 70-90°. As expected, under wet conditions, adhesion on a hydrophilic surface (glass) was lower than that on a hydrophobic surface (alkyl-silane monolayer on glass). Surprisingly under wet and dry conditions the adhesion was comparable on the hydrophobic surface, independent of the surface chemistry of the setal hairs. This work highlights the need to utilize morphology and surface chemistry in developing successful synthetic adhesives with desirable adhesion and self-cleaning properties.

  8. Influence of Soil Water Retention Properties on Hydrological Cycle and Water Budgeting Module Simulation

    Directory of Open Access Journals (Sweden)

    Hamid Čustović

    2011-03-01

    Full Text Available The complexity of water budgeting module as shown in this paper is represented in phases. By experimental measurement of precipitation and lysimetric measurement of percolation runoff the fi rst phase establishes monthly and annual soil-water budgets of skeletal and clayey soils, and hence the influence of soil water-retention potential on hydrologic cycle and water budget over a four year period in the area of Mostar. Then, a soil-water budget model is simulated in a simplified procedure in order to determine the corresponding soil productive water reserve (R for given soils.In this way, depending on R values, the output parameters of the simulated model may produce different results in: calculated surplus or percolation runoff, real evapotranspiration (RET and water deficit.The lysimetric measuring of the water input and output in skeletal and clayey soils determined significant differences in the water budgets of these, by physical properties, divergent soils. Such correlations indicate that there is a realistic possibility of computing new, relatively reliable and pragmatically significant agro-hydrological parameters using measured precipitation and calculated PET.Also, this paper addresses a correlative analysis between the apple and maize ET on one side, and evaporation measured by Piche and by Class A, as well as PET calculated by Thornthwaite, Turc and Penman, on the other side. The results show a reliable reaction between ET of apple and maize with E by Piche, while the same relation is even more reliable with Class A. Other methods in this correlative analysis are less reliable.

  9. Sphere impact and penetration into wet sand

    Science.gov (United States)

    Marston, J. O.; Vakarelski, I. U.; Thoroddsen, S. T.

    2012-08-01

    We present experimental results for the penetration of a solid sphere when released onto wet sand. We show, by measuring the final penetration depth, that the cohesion induced by the water can result in either a deeper or shallower penetration for a given release height compared to dry granular material. Thus the presence of water can either lubricate or stiffen the granular material. By assuming the shear rate is proportional to the impact velocity and using the depth-averaged stopping force in calculating the shear stress, we derive effective viscosities for the wet granular materials.

  10. Sphere impact and penetration into wet sand

    KAUST Repository

    Marston, J. O.

    2012-08-07

    We present experimental results for the penetration of a solid sphere when released onto wet sand. We show, by measuring the final penetration depth, that the cohesion induced by the water can result in either a deeper or shallower penetration for a given release height compared to dry granular material. Thus the presence of water can either lubricate or stiffen the granular material. By assuming the shear rate is proportional to the impact velocity and using the depth-averaged stopping force in calculating the shear stress, we derive effective viscosities for the wet granular materials.

  11. Interfacial properties of asphaltenes at toluene-water interfaces.

    Science.gov (United States)

    Zarkar, Sharli; Pauchard, Vincent; Farooq, Umer; Couzis, Alexander; Banerjee, Sanjoy

    2015-05-05

    Asphaltenes are "n-alkane insoluble" species in crude oil that stabilize water-in-oil emulsions. To understand asphaltene adsorption mechanisms at oil-water interfaces and coalescence blockage, we first studied the behavior in aliphatic oil-water systems in which asphaltenes are almost insoluble. They adsorbed as monomers, giving a unique master curve relating interfacial tension (IFT) to interfacial coverage through a Langmuir equation of state (EoS). The long-time surface coverage was independent of asphaltene bulk concentration and asymptotically approached the 2-D packing limit for polydisperse disks. On coalescence, the surface coverage exceeded the 2-D limit and the asphaltene film appeared to become solidlike, apparently undergoing a transition to a soft glassy material and blocking further coalescence. However, real systems consist of mixtures of aliphatic and aromatic components in which asphaltenes may be quite soluble. To understand solubility effects, we focus here on how the increased bulk solubility of asphaltenes affects their interfacial properties in comparison to aliphatic oil-water systems. Unlike the "almost irreversible" adsorption of asphaltenes where the asymptotic interfacial coverage was independent of the bulk concentration, an equilibrium surface pressure, dependent on bulk concentration, was obtained for toluene-water systems because of adsorption being balanced by desorption. The equilibrium surface coverage could be obtained from the short- and long-term Ward-Tordai approximations. The behavior of the equilibrium surface pressure with the equilibrium surface coverage was then derived. These data for various asphaltene concentrations were used to determine the EoS, which for toluene-water could also be fitted by the Langmuir EoS with Γ∞ = 3.3 molecule/nm(2), the same value as that found for these asphaltenes in aliphatic media. Asphaltene solubility in the bulk phase only appears to affect the adsorption isotherm but not the Eo

  12. The effects of replacing the water model while decoupling water-water and water-solute interactions on computed properties of simple salts

    Science.gov (United States)

    Li, Jicun; Wang, Feng

    2016-07-01

    The effects of decoupling the water-water and water-solute interactions are studied with selected mono-valent ions as the solute. Using the ion-water cross terms developed for the BLYPSP-4F water model, we replaced the water potential with WAIL, TIP4P, and TIP3P without changing the ion-water parameters. When the adaptive force matching (AFM) derived BLYPSP-4F model is replaced by the other AFM derived WAIL model, the difference in ion properties, such as hydration free energies, radial distribution functions, relative diffusion constants, is negligible, demonstrating the feasibility for combining AFM parameters from different sources. Interestingly, when the AFM-derived ion-water cross-terms are used with a non-AFM based water model, only small changes in the ion properties are observed. The final combined models with TIP3P or TIP4P water reproduce the salt hydration free energies within 6% of experiments. The feasibility of combining AFM models with other non-AFM models is of significance since such combinations allow more complex systems to be studied without specific parameterization. In addition, the study suggests an interesting prospect of reusing the cross-terms when a part of a general force field is replaced with a different model. The prevailing practice, which is to re-derive all cross-terms with combining rules, may not have been optimal.

  13. Membrane fouling and wetting in membrane distillation and their mitigation by novel membranes with special wettability.

    Science.gov (United States)

    Wang, Zhangxin; Lin, Shihong

    2017-04-01

    Membrane distillation (MD) has been identified as a promising technology to desalinate the hypersaline wastewaters from fracking and other industries. However, conventional hydrophobic MD membranes are highly susceptible to fouling and/or wetting by the hydrophobic and/or amphiphilic constituents in these wastewaters of complex compositions. This study systematically investigates the impact of the surface wetting properties on the membrane wetting and/or fouling behaviors in MD. Specifically, we compare the wetting and fouling resistance of three types of membranes of different wetting properties, including hydrophobic and omniphobic membranes as well as composite membranes with a hydrophobic substrate and a superhydrophilic top surface. We challenged the MD membranes with hypersaline feed solutions that contained a relatively high concentration of crude oil with and without added synthetic surfactants, Triton X-100. We found that the composite membranes with superhydrophilic top surface were robustly resistant to oil fouling in the absence of Triton X-100, but were subject to pore wetting in the presence of Triton X-100. On the other hand, the omniphobic membranes were easily fouled by oil-in-water emulsion without Triton X-100, but successfully sustained stable MD performance with Triton X-100 stabilized oil-in-water emulsion as the feed solution. In contrast, the conventional hydrophobic membranes failed readily regardless whether Triton X-100 was present, although via different mechanisms. These findings are corroborated by contact angle measures as well as oil-probe force spectroscopy. This study provides a holistic picture regarding how a hydrophobic membrane fails in MD and how we can leverage membranes with special wettability to prevent membrane failure in MD operations. Copyright © 2017 Elsevier Ltd. All rights reserved.

  14. A molecular dynamics study on surface properties of supercooled water

    Institute of Scientific and Technical Information of China (English)

    Lü; Yongjun

    2006-01-01

    [1]Basu J K,Hazra S,Sanyal M K.Growth mechanism of Langmuir-Blodgett films.Phys Rev Lett,1999,82:4675-4678[2]Taylor R S,Shields R L.Molecular-dynamics simulations of the ethanol liquid-vapor interface.J Chem Phys,2003,119:12569-12576[3]Velev O D,Gurkov T D,Ivanov I B,et al.Abnormal thickness and stability of nonequilibrium liquid films.Phys Rev Lett,1995,75:264-267[4]Weng J G,Park S,Lukes J R,et al.Molecular dynamics investigation of thickness effect on liquid films.J Chem Phys,2000,113:5917-5923[5]Zakharov V V,Brodskaya E N,Laaksonen A.Surface tension of water droplets:A molecular dynamics study of model and size dependencies.J Chem Phys,1997,107:10675-10683[6]Wang J Z,Chen M,Guo Z Y.A two-dimensional molecular dynamics simulation of liquid-vapor nucleation.Chin Sci Bull,2003,48(7):623-626[7]Guissani Y,Guillot B.A computer simulation study of the liquid-vapor coexistence curve of water.J Chem Phys,1993,98:8221-8235[8]Wilson M A,Pohorille A,Pratt L R.Surface potential of the water liquid-vapor interface.J Chem Phys,1988,88:3281-3285[9]Alejandre J,Tildesley D J,Chapela G A.Molecular dynamics simulation of the orthobaric densities and surface tension of water.J Chem Phys,1995,102:4574-4583[10]Matsumoto M,Kataoka Y.Study on liquid-vapor interface of water (Ⅰ):Simulational results of thermodynamic properties and orientational structure.J Chem Phys,1988,88:3233-3245[11]Floriano M A,Angell C A.Surface tension and molar surface free energy and entropy of water to-27.2℃.J Phys Chem,1990,94:4199-4202[12]Jorgensen W L,Chandrasekhar J,Madura J D.Comparison of simple potential functions for simulating liquid water.J Chem Phys,1993,79:926-935[13]Berendsen H J C,Grigera J R,Straatsma T P.The missing term in effective pair potentials.J Phys Chem,1987,91:6269-6271[14]Arbuckle B W,Clancy P.Effects of the Ewald sum on the free energy of the extended simple point charge model for water.J Chem Phys,2002,116:5090-5098[15]Tarazona P,Chacon E,Reinaldo-Falagan M,et al

  15. FATIGUE PROPERTIES OF AUSTEMPERED DUCTILE IRON (ADI)IN WATER ENVIRONMENT

    Institute of Scientific and Technical Information of China (English)

    Q.Z.Cai; B.K.Wei; Y.Tanaka

    2004-01-01

    The acicular ferrite in austempered ductile iron(ADI)matrix around graphite was corroded preferentially in wet condition,promoting crack origination and propagation and resulting in the disappearance of ADI fatigue limit.ADI fatigue strength was gradually reduced with increasing the time of test and was reduced by 50% in wet condition at 107 cycles compared with the fatigue limit in dry condition.The fatigue strength variation of ferritic ductile iron in wet condition was similar to that of ADI.The ferritic ductile iron,however,has better corrosion resistance so that the fatigue strength was lowered only by 10% in wet condition at 107 cycles compared with the fatigue limit in dry condition.On the other hand,the fatigue limits of A DI and ferritic ductile iron were dropped by 32% and 25% in tap water dipping 480h/dry condition respectively compared with those in dry condition.The reduction of fatigue limit was attributed to corrosion pits formation correlated with stress concentration,resulting in origination and propagation of fatigue crack.

  16. Antioxidant Properties of Water-Soluble Gum from Flaxseed Hulls.

    Science.gov (United States)

    Bouaziz, Fatma; Koubaa, Mohamed; Barba, Francisco J; Roohinejad, Shahin; Chaabouni, Semia Ellouz

    2016-08-02

    Soluble flaxseed gum (SFG) was extracted from flax (Linum usitatissimum) hulls using hot water, and its functional groups and antioxidant properties were investigated using infrared spectroscopy and different antioxidant assays (2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid (ABTS), reducing power capacity, and β-carotene bleaching inhibition assay), respectively. The antioxidant capacity of SFG showed interesting DPPH radical-scavenging capacity (IC50 SFG = 2.5 mg·mL(-1)), strong ABTS radical scavenging activity (% inhibition ABTS = 75.6% ± 2.6% at 40 mg·mL(-1)), high reducing power capacity (RPSFG = 5 mg·mL(-1)), and potent β-carotene bleaching inhibition activity (IC50 SFG = 10 mg·mL(-1)). All of the obtained results demonstrate the promising potential use of SFG in numerous industrial applications, and a way to valorize flaxseed hulls.

  17. Physicochemical properties of calcium polycarbophil, a water-absorbing polymer.

    Science.gov (United States)

    Yamada, T; Kitayama, M; Yamazaki, M; Nagata, O; Tamaj, I; Tsuji, A

    1996-07-01

    The physicochemical properties of calcium polycarbophil were examined. Calcium polycarbophil was decalcified rapidly under acidic conditions, affording polycarbophil. Polycarbophil absorbed about 10 times its own weight of water under acidic conditions, but the swelling ratio markedly increased at above pH 4.0 and reached 70 times the initial weight under neutral conditions. The swelling of polycarbophil was not affected by non-ionic osmolarity, but was affected by ionic strength, showing a decrease with increase of ionic strength. Monovalent metal ions such as sodium and potassium ions in gastrointestinal fluid did not reduce the equilibrium swelling of polycarbophil, but divalent ions such as calcium and magnesium ions did. However, calcium ion only slightly reduced the equilibrium swelling under sodium-rich conditions. The viscosity (as an indicator of fluidity) of polycarbophil was larger than that of CMC-Na at every shear rate and polymer content examined.

  18. Analysis of Water Properties and Geostrophic Currents in Fiji Waters Before and After Tropical Cyclone Gene

    Directory of Open Access Journals (Sweden)

    Shivneel Prasad

    2009-01-01

    Full Text Available Problem statement: Water properties influence ocean primary production and drive the ocean food chain. This study depicts changes in temperature and salinity and its effects on geostrophic currents near Fiji before and after Tropical Cyclone (TC Gene. Approach: Available Argo float data from 6 January-4 February 2008 were used for analysis since TC Gene passed the area on 28 January 2008. The dynamic height and geostrophic current data were obtained from the Aviso website. Results: The thermocline depth increased by 20 m after the cyclone. A temperature drop of approximately 3°C was also noticed in the study area. Using this drop in temperature, the heat energy removed by the cyclone was calculated to be 0.095 MWh m-2. Salinity profiles showed an increase of 0.42 psu to a depth of 35 m after the cyclone. Changes in salinity and temperature of water may also cause changes in the dynamic height and in turn the geostrophic current patterns. After plotting the geostrophic current vectors, it was observed that the current patterns changed significantly after TC gene. Seasonal changes were also evident before the cyclone. Conclusion/Recommendations: Although the lifespan of TC gene was short, its effect on the water properties near Fiji was significant as it completely changed the geostrophic current patterns and this can have a huge implication on marine life.

  19. The Properties of Water and their Applications for Training

    Science.gov (United States)

    Torres-Ronda, Lorena; del Alcázar, Xavi Schelling i

    2014-01-01

    The biological effects of immersion in water, which are related to the fundamental principles of hydrodynamics, may be beneficial in certain training contexts. The effects and physical properties of water, such as density, hydrostatic pressure and buoyancy are highly useful resources for training, when used as a counterbalance to gravity, resistance, a compressor and a thermal conductor. Not only does the aquatic medium enable a wider range of activities to be used in a context of low joint impact, but it also constitutes a useful tool in relation to sports rehabilitation, since it allows the athlete to return to training earlier or to continue with high-intensity exercise while ensuring both low joint impact and greater comfort for the individual concerned. Moreover, this medium enables the stimulation of metabolic and neuromuscular systems, followed by their corresponding physiological adaptations allowing both to maintain and improve athletic performance. Hydrotherapy can also play a beneficial role in an athlete’s recovery, helping to prevent as well as treat muscle damage and soreness following exercise. PMID:25713684

  20. The Properties of Water and their Applications for Training

    Directory of Open Access Journals (Sweden)

    Torres-Ronda Lorena

    2014-12-01

    Full Text Available The biological effects of immersion in water, which are related to the fundamental principles of hydrodynamics, may be beneficial in certain training contexts. The effects and physical properties of water, such as density, hydrostatic pressure and buoyancy are highly useful resources for training, when used as a counterbalance to gravity, resistance, a compressor and a thermal conductor. Not only does the aquatic medium enable a wider range of activities to be used in a context of low joint impact, but it also constitutes a useful tool in relation to sports rehabilitation, since it allows the athlete to return to training earlier or to continue with high-intensity exercise while ensuring both low joint impact and greater comfort for the individual concerned. Moreover, this medium enables the stimulation of metabolic and neuromuscular systems, followed by their corresponding physiological adaptations allowing both to maintain and improve athletic performance. Hydrotherapy can also play a beneficial role in an athlete’s recovery, helping to prevent as well as treat muscle damage and soreness following exercise.

  1. Wetting of real surfaces

    CERN Document Server

    Bormashenko, Edward Yu

    2013-01-01

    The problem of wetting and drop dynamics on various surfaces is very interesting from both the scientificas well as thepractical viewpoint, and subject of intense research.The results are scattered across papers in journals, sothis workwill meet the need for a unifying, comprehensive work.

  2. Wet Macular Degeneration

    Science.gov (United States)

    ... macular degeneration Overview By Mayo Clinic Staff Wet macular degeneration is a chronic eye disease that causes blurred vision or a blind spot in your visual field. It's generally caused by abnormal blood vessels that leak fluid or blood into ... macular degeneration is one of two types of age-related ...

  3. Fluorine- and iron-modified hierarchical anatase microsphere photocatalyst for water cleaning: facile wet chemical synthesis and wavelength-sensitive photocatalytic reactivity.

    Science.gov (United States)

    Liu, Shaohong; Sun, Xudong; Li, Ji-Guang; Li, Xiaodong; Xiu, Zhimeng; Yang, He; Xue, Xiangxin

    2010-03-16

    High photocatalytic efficiency, easy recovery, and no biological toxicity are three key properties related to the practical application of anatase photocatalyst in water cleaning, but seem to be incompatible. Nanoparticles-constructed hierarchical anatase microspheres with high crystallinity and good dispersion prepared in this study via one-step solution processing at 90 degrees C under atmospheric pressure by using ammonium fluotitanate as the titanium source and urea as the precipitant can reconcile these three requirements. The hierarchical microspheres were found to grow via an aggregative mechanism, and contact recrystallization occurred at high additions of the FeCl(3) electrolyte into the reaction system. Simultaneous incorporation of fluorine and iron into the TiO(2) matrix was confirmed by combined analysis of X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, and UV-vis absorption spectroscopy. Surface structure and morphology changes of the microspheres induced by high-temperature annealing were clearly observed by field-emission scanning electron microscopy, especially for the phase-transformed particles. The original nanoparticles-constructed rough surfaces partially became smooth, resulting in a sharp drop in photocatalytic efficiency. Interestingly, iron loading has detrimental effects on the visible-light photocatalytic activity of both the as-prepared and the postannealed anatase microspheres but greatly enhances the photocatalytic activity of the as-prepared anatase microspheres under UV irradiation. No matter under UV or visible-light irradiation, the fluorine-loaded anatase microspheres and especially the postannealed ones show excellent photocatalytic performance. The underlying mechanism of fluorine and iron loading on the photocatalytic efficacy of the anatase microspheres was discussed in detail. Beyond photocatalytic applications, this kind of material is of great importance to the assembling of

  4. Water Quality and optical properties of Crater Lake, Oregon

    Science.gov (United States)

    Larson, Gary L.; Hoffman, Robert L.; McIntire, C.D.; Buktenica, M.W.; Girdner, Scott

    2007-01-01

    We examine observations of key limnological properties (primarily temperature, salinity, and dissolved oxygen), measured over a 14-year period in Crater Lake, Oregon, and discuss variability in the hypolimnion on time scales of days to a decade. During some years (e.g., 1994a??1995), higher-than-average wintertime deep convection and ventilation led to the removal of significant amounts of heat and salt from the hypolimnion, while dissolved oxygen concentrations increase. In other years, such as the winter of 1996a??1997, heat and salt concentrations increase throughout the year and dissolved oxygen levels drop, indicating conditions were dominated by the background geothermal inputs and dissolved oxygen consumption by bacteria (i.e., minimal deep convection). Over the entire 14 year period, no statistically significant trend was observed in the annual hypolimnetic heat and salt content. Measurements from several thermistors moored in the hypolimnion provide new insight into the time and space scales of the deep convection events. For some events, cool water intrusions are observed sequentially, from shallower depths to deeper depths, suggesting vertical mixing or advection from above. For other events, the cooling is observed first at the deepest sensors, suggesting a thin, cold water pulse that flows along the bottom and mixes more slowly upwards into the basin. In both cases, the source waters must originate from the epilimnion. Conditions during a strong ventilation year (1994a??1995) and a weak ventilation year (1996a??1997) were compared. The results suggest the major difference between these 2 years was the evolution of the stratification in the epilimnion during the first few weeks of reverse stratification such that thermobaric instabilities were easier to form during 1995 thana?#1997. Thus, the details of surface cooling and wind-driven mixing during the early stages ofa?#reverse stratification may determine the neta?#amount of ventilation possible during

  5. Inferring inherent optical properties and water constituent profiles from apparent optical properties.

    Science.gov (United States)

    Fan, Yongzhen; Li, Wei; Calzado, Violeta Sanjuan; Trees, Charles; Stamnes, Snorre; Fournier, Georges; McKee, David; Stamnes, Knut

    2015-07-27

    The BP09 experiment conducted by the Centre for Maritime Research and Experimentation in the Ligurian Sea in March 2009 provided paired vertical profiles of nadir-viewing radiances L(u)(z) and downward irradiances E(d)(z) and inherent optical properties (IOPs, absorption, scattering and backscattering coefficients). An inversion algorithm was implemented to retrieve IOPs from apparent optical properties (AOPs, radiance reflectance R(L), irradiance reflectance R(E) and diffuse attenuation coefficient K(d)) derived from the radiometric measurements. Then another inversion algorithm was developed to infer vertical profiles of water constituent concentrations, including chlorophyll-a concentration, non-algal particle concentration, and colored dissolved organic matter from the retrieved IOPs based on a bio-optical model. The algorithm was tested on a synthetic dataset and found to give reliable results with an accuracy better than 1%. When the algorithm was applied to the BP09 dataset it was found that good retrievals of IOPs could be obtained for sufficiently deep waters, i.e. for L(u)(z) and E(d)(z) measurements conducted to depths of 50 m or more. This requirement needs to be satisfied in order to obtain a good estimation of the backscattering coefficient. For such radiometric measurements a correlation of 0.88, 0.96 and 0.93 was found between retrieved and measured absorption, scattering and backscattering coefficients, respectively. A comparison between water constituent values derived from the measured IOPs and in-situ measured values, yielded a correlation of 0.80, 0.78, and 0.73 for chlorophyll-a concentration, non-algal particle concentration, and absorption coefficient of colored dissolved organic matter at 443 nm, respectively. This comparison indicates that adjustments to the bio-optical model are needed in order to obtain a better match between inferred and measured water constituent values in the Ligurian Sea using the methodology developed in this paper.

  6. WET STRENGTH PAPER REPULPING:LABORATORY EVALUATION

    Institute of Scientific and Technical Information of China (English)

    Nishi K. Bhardwaj; Vikas Rajan; A.G. Kulkarni

    2004-01-01

    The recycling of wet strength papers in a normal recycling mill is often troublesome due to the severe operating conditions required to defibre wet strength papers. The various methods are presented which will quickly allow mills to determine the most effective pulping aids to use when repulping wet strength papers. The repulping of wet strength paper with inorganic chemicals was investigated in the laboratory. The effects of major variables, that is,repulping time, pulp consistency, soaking time,temperature, and reactant concentration in the repulping stage were examined using Plackett-Burman design. The repulping time was the most crucial & influential process variable affecting repulping characteristic and formation related properties. The more significant repulping process variables affecting pulp yield were repulping time,soaking temperature and pulp consistency whereas for formation index and feature size, repulping time,pulp consistency, soaking temperature and time were the more important variables. The formation index is increased by an increase in repulping time, pulp consistency and soaking time whereas the feature size is decreased by an increase in repulping time,soaking temperature and pulp consistency. The formation index and the rejects were more sensitive to changes in process variables than were the feature size or the pulp yield. The pulp recycled from wet strength waste paper had good physical strength properties.

  7. Catalytic gasification of dry and wet biomass

    NARCIS (Netherlands)

    van Rossum, G.; Potic, B.; Kersten, Sascha R.A.; van Swaaij, Willibrordus Petrus Maria

    2009-01-01

    Catalytic gasification of dry biomass and of wet biomass streams in hot compressed water are reviewed and discussed as potential technologies for the production of synthesis gas, hydrogen- and methane-rich gas. Next to literature data also new experimental results from our laboratory on catalytic

  8. Physical properties of the sub-micrometer aerosol over the Amazon rain forest during the wet-to-dry season transition - comparison of modeled and measured CCN concentrations

    Directory of Open Access Journals (Sweden)

    J. Rissler

    2004-01-01

    Full Text Available Sub-micrometer atmospheric aerosol particles were studied in the Amazon region, 125 km northeast of Manaus, Brazil (-1°55.2'S, 59°28.1'W. The measurements were performed during the wet-to-dry transition period, 4-28 July 2001 as part of the LBA (Large-Scale Biosphere Atmosphere Experiment in Amazonia CLAIRE-2001 (Cooperative LBA Airborne Regional Experiment experiment. The number size distribution was measured with two parallel differential mobility analyzers, the hygroscopic growth at 90% RH with a Hygroscopic Tandem Mobility Analyzer (H-TDMA and the concentrations of cloud condensation nuclei (CCN with a cloud condensation nuclei counter. A model was developed that uses the H-TDMA data to predict the number of soluble molecules or ions in the individual particles and the corresponding minimum particle diameter for activation into a cloud droplet at a certain supersaturation. Integrating the number size distribution above this diameter, CCN concentrations were predicted with a time resolution of 10 min and compared to the measured concentrations. During the study period, three different air masses were identified and compared: clean background, air influenced by aged biomass burning, and moderately polluted air from recent local biomass burning. For the clean period 2001, similar number size distributions and hygroscopic behavior were observed as during the wet season at the same site in 1998, with mostly internally mixed particles of low diameter growth factor (~1.3 taken from dry to 90% RH. During the periods influenced by biomass burning the hygroscopic growth changed slightly, but the largest difference was seen in the number size distribution. The CCN model was found to be successful in predicting the measured CCN concentrations, typically within 25%. A sensitivity study showed relatively small dependence on the assumption of which model salt that was used to predict CCN concentrations from H-TDMA data. One strength of using H-TDMA data

  9. Time-varying wetting behavior on copper wafer treated by wet-etching

    Energy Technology Data Exchange (ETDEWEB)

    Tu, Sheng-Hung; Wu, Chuan-Chang [Department of Chemical and Materials Engineering, National Central University, Jhongli 320, Taiwan, ROC (China); Wu, Hsing-Chen [Advanced Technology Materials Inc, Hsinchu 310, Taiwan, ROC (China); Cheng, Shao-Liang [Department of Chemical and Materials Engineering, National Central University, Jhongli 320, Taiwan, ROC (China); Sheng, Yu-Jane, E-mail: yjsheng@ntu.edu.tw [Department of Chemical Engineering, National Taiwan University, Taipei 106, Taiwan, ROC (China); Tsao, Heng-Kwong, E-mail: hktsao@cc.ncu.edu.tw [Department of Chemical and Materials Engineering, National Central University, Jhongli 320, Taiwan, ROC (China)

    2015-06-30

    Graphical abstract: - Highlights: • A thin oxide layer always remains on surfaces of Cu wafers after aqueous etching. • A pure Cu wafer is obtained by the HAc treatment and the water CA is about 45°. • The oxide layer and CA grow with time after the Cu wafer is exposed to air. • Surface roughness and hydrophobicity of pure Cu wafers grow rapidly in vacuum. - Abstract: The wet cleaning process in semiconductor fabrication often involves the immersion of the copper wafer into etching solutions and thereby its surface properties are significantly altered. The wetting behavior of a copper film deposited on silicon wafer is investigated after a short dip in various etching solutions. The etchants include glacial acetic acid and dilute solutions of nitric acid, hydrofluoric acid, and tetramethylammonium hydroxide. It was found that in most cases a thin oxide layer still remains on the surface of as-received Cu wafers when they are subject to etching treatments. However, a pure Cu wafer can be obtained by the glacial acetic acid treatment and its water contact angle (CA) is about 45°. As the pure Cu wafer is placed in the ambient condition, the oxide thickness grows rapidly to the range of 10–20 Å within 3 h and the CA on the hydrophilic surface also rises. In the vacuum, it is surprising to find that the CA and surface roughness of the pure Cu wafer can grow significantly. These interesting results may be attributed to the rearrangement of surface Cu atoms to reduce the surface free energy.

  10. Wetting behavior of multi-walled carbon nanotube nanofluids

    Science.gov (United States)

    Karthikeyan, A.; Coulombe, S.; Kietzig, A. M.

    2017-03-01

    Nanofluids—engineered colloidal suspensions in base liquids—have captivated the interest of researchers over the last two decades for various existing as well as emerging technological applications. The main impetus for the synthesis of such novel nanocomposite liquids is the potential to alter properties of the base liquid, such as its viscosity, thermal conductivity, and surface tension, and to introduce specific optical and magnetic properties. Numerous studies suggest trends and explanations for the effects associated with the addition of nanoparticles, and that deviation from the base liquid properties are dependent on nanoparticle concentration. However, there remains a certain ambiguity in the available literature. The wetting behavior and surface tension of nanofluids are particular examples where highly conflicting results exist. In this study, we used multi-walled carbon nanotubes (MWCNTs) functionalized by plasma treatment and dispersed in reverse osmosis water and 99% anhydrous ethanol. Our observations reveal that the surface tension and wetting behavior of the stable aqueous and ethanol-based nanofluids containing plasma functionalized MWCNTs are unaffected by the MWCNT loading up to 120 (0.012) and ∼210 (0.021) ppm (vol%), respectively. The ethanol-based MWCNT nanofluids allowed us to extend the study to higher loadings, and a linear increase of the surface tension past ∼200 ppm was observed. Conversely, nanofluids containing non-functionalized or surfactant-stabilized MWCNTs show drastically different contact angle values when compared to the base liquids even at very low concentrations (less than 100 ppm). We demonstrate that the stability of nanofluid and method of stabilization are crucial parameters in determining the wetting behavior of nanofluids.

  11. Wetting behavior of multi-walled carbon nanotube nanofluids.

    Science.gov (United States)

    Karthikeyan, A; Coulombe, S; Kietzig, A M

    2017-03-10

    Nanofluids-engineered colloidal suspensions in base liquids-have captivated the interest of researchers over the last two decades for various existing as well as emerging technological applications. The main impetus for the synthesis of such novel nanocomposite liquids is the potential to alter properties of the base liquid, such as its viscosity, thermal conductivity, and surface tension, and to introduce specific optical and magnetic properties. Numerous studies suggest trends and explanations for the effects associated with the addition of nanoparticles, and that deviation from the base liquid properties are dependent on nanoparticle concentration. However, there remains a certain ambiguity in the available literature. The wetting behavior and surface tension of nanofluids are particular examples where highly conflicting results exist. In this study, we used multi-walled carbon nanotubes (MWCNTs) functionalized by plasma treatment and dispersed in reverse osmosis water and 99% anhydrous ethanol. Our observations reveal that the surface tension and wetting behavior of the stable aqueous and ethanol-based nanofluids containing plasma functionalized MWCNTs are unaffected by the MWCNT loading up to 120 (0.012) and ∼210 (0.021) ppm (vol%), respectively. The ethanol-based MWCNT nanofluids allowed us to extend the study to higher loadings, and a linear increase of the surface tension past ∼200 ppm was observed. Conversely, nanofluids containing non-functionalized or surfactant-stabilized MWCNTs show drastically different contact angle values when compared to the base liquids even at very low concentrations (less than 100 ppm). We demonstrate that the stability of nanofluid and method of stabilization are crucial parameters in determining the wetting behavior of nanofluids.

  12. Design Aspects of Wet Scrubber System

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hyun-Chul; Bang, Young-suk; Jung, Woo-Young; Lee, Doo-Yong [FNC Technology Co. Ltd., Yongin (Korea, Republic of)

    2015-10-15

    The water pool in the wet scrubber system has advantage to cope with decay heat based on the thermal hydraulic balance such as condensation and evaporation inside it. This study focuses on the design aspects of the wet scrubber system to estimate the required water pool mass during the mission time and size of the scrubbing tank including inner structures. The design of the wet scrubber system include the estimation of the required water mass during the mission time and sizing of the scrubber vessel to contain the water pool. The condensation due to the inlet steam and evaporation due to the steam and non-condensable gas superheat and decay heat from filtered fission products should be considered to estimate the water mass required to maintain its function during the mission time. On the other hand, the level swelling due to the noncondensable gas is another important design aspect on the sizing of the scrubber vessel and determination of the entry elevation of the filtration components such as the droplet separator or filter. The minimum water level based on the minimum collapsed water level should be higher than the exit of scrubber nozzle.

  13. A simulation study on the thermal and wetting behavior of alkane thiol SAM on gold (111) surface

    Institute of Scientific and Technical Information of China (English)

    J. Meena Devi

    2014-01-01

    Molecular dynamics simulations have been performed to investigate the structural, thermal and wetting properties of self-assembled monolayer (SAM) of alkane thiol on gold surface. The specific heat capacity of the gold SAM surface was found to linearly increase with the temperature in the range 100-300 K. It was found to drop down at 400 K and this decrease might be attributed to the disorder of the SAM chains. Hydration of gold SAM surface for two different terminal groups, namely methyl (hydrophobic), and hydroxy (hydrophilic) was studied at room temperature. The difference in their wetting behavior and the structure of their interfacial water were examined from the estimation of the z density profile, radial distribution function, hydrogen bonds and orientation of water dipoles in the interfacial region. The present simulation results suggest that the wetting behavior of the gold SAM surface can be modified by altering the terminal functional group of the SAM chains.

  14. Impact of a molecular wetting layer on the structural and optical properties of tin(II)-phthalocyanine multilayers on Ag(111)

    Science.gov (United States)

    Gruenewald, Marco; Peuker, Julia; Meissner, Matthias; Sojka, Falko; Forker, Roman; Fritz, Torsten

    2016-03-01

    We investigate ultrathin highly ordered layers of tin(II)-phthalocyanine (SnPc) on top of a monolayer (ML) of 3,4,9,10-perylenetetracarboxylic dianhydride (PTCDA) on Ag(111). The films are analyzed structurally by means of scanning tunneling microscopy (STM) and low-energy electron diffraction (LEED) as well as optically using differential reflectance spectroscopy (DRS). We find that the first ML of SnPc is entirely rearranged upon bilayer (BL) formation, yielding a commensurate registry in higher-order coincidence with the underlying PTCDA lattice. SnPc layers adsorbed on top self-assemble in further BLs. Within each BL the molecules are arranged pairwise, i.e., stacked as physical dimers, providing a characteristic absorption spectrum with strongly redshifted components compared to SnPc monomers. This altered spectral envelope mainly originates from strong orbital overlap of stacked molecules within each BL. In contrast, adjacent BLs show only weak orbital overlap, which is responsible for an additional redshift of the low-energy transition band. Our results demonstrate that a simple modification of the metal substrate surface, e.g., by a PTCDA wetting layer, has beneficial effects on structural ordering of SnPc multilayers adsorbed on top. The impact on the optical absorption spectrum manifests in a narrow and intense absorption peak in the near-infrared spectral region which is significantly less pronounced if the PTCDA layer is omitted.

  15. Wet foams hydrophobized by amphiphiles to give Al2O3 porous ceramics

    Science.gov (United States)

    Pokhrel, Ashish; Park, Jung Gyu; Kim, Ik Jin

    2012-05-01

    Wet chemical method to prepare ceramic foams with antecedent stability using inorganic particles (Al2O3,SiO2 etc.) which are in situ hydrophobized upon adsorption of short-chain amphiphilic molecules in the wet state and heightened mechanical property in the sintered state was developed. These wet foams are stable over several days and show no bubble coarsening nor drainage or creaming. This long-term stability is achieved through the irreversible adsorption of partially hydrophobized colloidal particles to the air-water interface using short-chain amphiphiles to in situ modify the wetting behavior of the particle surface based on the observations of Pickering emulsions. As a result, the suspension is foamed homogeneously throughout its entire volume and porous bulk materials can be produced upon drying and sintering. Wet foams featuring average bubble sizes between 30 and 300μm and sintered foams with porosity from 50 to 85% were obtained by adjusting the amphiphile - particle concentration, and additives in the initial suspension. Cells were mostly closed with an average size of approximately 150 μm. Single cells were separated by walls with minimum thicknesses of 1-3 μm.

  16. The effect of superhydrophobic wetting state on corrosion protection--the AKD example.

    Science.gov (United States)

    Ejenstam, Lina; Ovaskainen, Louise; Rodriguez-Meizoso, Irene; Wågberg, Lars; Pan, Jinshan; Swerin, Agne; Claesson, Per M

    2013-12-15

    Corrosion is of considerable concern whenever metal is used as construction material. In this study we address whether superhydrophobic coatings could be used as part of an environmentally friendly corrosion-protective system, and specific focus is put on how the wetting regime of a superhydrophobic coating affects corrosion inhibition. Superhydrophobic alkyl ketene dimer (AKD) wax coatings were produced, using different methods resulting in hierarchical structures, where the coatings exhibit the same surface chemistry but different wetting regimes. Contact angle measurements, ESEM, confocal Raman microscopy, open circuit potential and electrochemical impedance spectroscopy were used to evaluate the surfaces. Remarkably high impedance values of 10(10)Ω cm(2) (at 10(-2) Hz) were reached for the sample showing superhydrophobic lotus-like wetting. Simultaneous open circuit potential measurements suggest that the circuit is broken, most likely due to the formation of a thin air layer at the coating-water interface that inhibits ion transport from the electrolyte to the metal substrate. The remaining samples, showing superhydrophobic wetting in the rose state and hydrophobic Wenzel-like wetting, showed less promising corrosion-protective properties. Due to the absence of air films on these surfaces the coatings were penetrated by the electrolyte, which allowed the corrosion reaction to proceed. Copyright © 2013 Elsevier Inc. All rights reserved.

  17. Controlled preparation of wet granular media reveals limits to lizard burial ability

    Science.gov (United States)

    Sharpe, Sarah S.; Kuckuk, Robyn; Goldman, Daniel I.

    2015-07-01

    Many animals move within ground composed of granular media (GM); the resistive properties of such substrates can depend on water content and compaction, but little is known about how such parameters affect locomotion or the physics of drag and penetration. Using apparatus to control compaction of GM, our recent studies of movement in dry GM have revealed locomotion strategies of specialized dry-sand-swimming reptiles. However, these animals represent a small fraction of the diversity and presumed burial strategies of fossorial reptilian fauna. Here we develop a system to create states of wet GM of varying moisture content and compaction in quantities sufficient to study the burial and subsurface locomotion of the Ocellated skink (C. ocellatus), a generalist lizard. X-ray imaging revealed that in wet and dry GM the lizard slowly buried (≈ 30 s) propagating a wave from head to tail, while moving in a start-stop motion. During forward movement, the head oscillated, and the forelimb on the convex side of the body propelled the animal. Although body kinematics and ‘slip’ were similar in both substrates, the burial depth was smaller in wet GM. Penetration and drag force experiments on smooth cylinders revealed that wet GM was ≈ 4× more resistive than dry GM. In total, our measurements indicate that while the rheology of the dry and wet GM differ substantially, the lizard's burial motor pattern is conserved across substrates, while its burial depth is largely constrained by environmental resistance.

  18. Interfacial properties of dissolved crude oil components in produced water

    OpenAIRE

    Eftekhardadkhah, Mona

    2013-01-01

    Produced water is a mixture of water trapped in underground formations and injection water that is brought to the surface along with oil or gas. In general, produced water is a mixture of dispersed oil in water (o/w), dissolved organic compounds (including hydrocarbons), residual concentration of chemical additives from the production line, heavy metals, dissolved minerals and suspended solids.In the year 2011, 131 million m3 of produced water were discharged on the Norwegian Continental Shel...

  19. Properties of atmospheric humic-like substances – water system

    Directory of Open Access Journals (Sweden)

    G. Láng

    2008-02-01

    Full Text Available Urban-type PM2.5-fraction aerosol samples were collected and samples of pure atmospheric humic-like substances (HULIS were isolated from them. Atmospheric concentrations of organic carbon (OC, water soluble organic carbon (WSOC and HULIS were determined, and UV/Vis spectroscopic properties, solubility and conductivity of HULIS in aqueous samples were investigated. Mean atmospheric concentrations of OC and WSOC were 8.5 and 4.6 μg m−3, respectively. Hydrophilic WSOC accounted for 39% of WSOC, carbon in HULIS made up 47% of WSOC, and 14% of WSOC was retained on the separation column by irreversible adsorption. Average molecular mass and aromatic carbon abundance of HULIS were both estimated from molar absorptivity to be 556 Da and 12%, respectively. Both results are substantially smaller than for standard reference fulvic acids, which imply different mechanisms for the formation processes of atmospheric HULIS and aquatic or terrestrial humic matter. HULIS were found to be water soluble as ionic unimers with a saturation concentration of 2–3 g l−1. Their solubility increased again with total HULIS concentration being above approximately 4 g l−1, which was most likely explained by the formation of HULIS aggregates. Solubility increased linearly from approximately 5 up to 20 g l−1 of dissolved HULIS concentration. The ionic dissolution was confirmed by electrochemical conductivity in the investigated concentration interval. Limiting molar conductivity was extrapolated and this was utilized to determine the apparent dissociation degree of HULIS for different concentrations. The dissociation degree was further applied to derive the concentration dependence of the van't Hoff factor of HULIS. The van't Hoff factor decreased monotonically with HULIS concentration; the decrease was substantial for dilute solutions and the relationship became weak for rather concentrated solutions.

  20. Properties of atmospheric humic-like substances ─ water system

    Directory of Open Access Journals (Sweden)

    G. G. Láng

    2008-04-01

    Full Text Available Urban-type PM2.5-fraction aerosol samples were collected and samples of pure atmospheric humic-like substances (HULIS were isolated from them. Atmospheric concentrations of organic carbon (OC, water soluble organic carbon (WSOC and HULIS were determined, and UV/Vis spectroscopic properties, solubility and conductivity of HULIS in aqueous samples were investigated. Atmospheric concentrations of OC and WSOC were 8.5 and 4.6 μg m−3, respectively. Hydrophilic WSOC accounted for 39% of WSOC, carbon in HULIS made up 47% of WSOC, and 14% of WSOC was retained on the separation column by irreversible adsorption. Overall average molecular mass and aromatic carbon abundance of HULIS were estimated from molar absorptivity to be 556 Da and 12%, respectively. Both results are substantially smaller than for standard reference fulvic acids, which imply different mechanisms for the formation processes of atmospheric HULIS and aquatic or terrestrial humic matter. HULIS were found to be water soluble as ionic unimers with a saturation concentration of 2–3 g l−1. Their solubility increased again with total HULIS concentration being above approximately 4 g l−1, which was most likely explained by the formation of HULIS aggregates. Solubility increased linearly from approximately 5 up to 20 g l−1 of dissolved HULIS concentration. The ionic dissolution was confirmed by electrochemical conductivity in the investigated concentration interval. Limiting molar conductivity was extrapolated and this was utilized to determine the apparent dissociation degree of HULIS for different concentrations. The dissociation degree was further applied to derive the concentration dependence