COVER ILLUSTRATION: Complexities of splashing

NASA Astrophysics Data System (ADS)

Deegan, R. D.; Brunet, P.; Eggers, J.

2008-01-01

We study the impact of a drop of liquid onto a thin layer of the same liquid. We give an overview of the sequence of events that occur as the two most important dimensionless control parameters are varied. In particular, multiple cohorts of droplets can be ejected at different stages after impact due to different mechanisms. Edgerton's famous Milkdrop Coronet is only observed for a narrow range of parameters. Outside this range, the splash is either qualitatively different, or suffers from a much lower level of regularity.

Method of fabrication of supported liquid membranes

DOEpatents

Luebke, David R.; Hong, Lei; Myers, Christina R.

2015-11-17

Method for the fabrication of a supported liquid membrane having a dense layer in contact with a porous layer, and a membrane liquid layer within the interconnected pores of the porous layer. The dense layer is comprised of a solidified material having an average pore size less than or equal to about 0.1 nanometer, while the porous layer is comprised of a plurality of interconnected pores and has an average pore size greater than 10 nanometers. The supported liquid membrane is fabricated through the preparation of a casting solution of a membrane liquid and a volatile solvent. A pressure difference is established across the dense layer and porous layer, the casting solution is applied to the porous layer, and the low viscosity casting solution is drawn toward the dense layer. The volatile solvent is evaporated and the membrane liquid precipitates, generating a membrane liquid layer in close proximity to the dense layer.

Navy Additive Manufacturing: Policy Analysis for Future DLA Material Support

DTIC Science & Technology

2014-12-01

printing (3DP) for it is a direct offshoot of inkjet paper printing. There are two subtypes to his modality that both involve depositing droplets of...liquid material in layers. The first is material jetting, which uses an inkjet head to move across a print area and deposit a polymer or wax in layers... inkjet printer, this means that the product can be made in multiple colors. Supports have to be built, but they can be made of a different material that

Microelectromechanical-System-Based Variable-Focus Liquid Lens for Capsule Endoscopes

NASA Astrophysics Data System (ADS)

Seo, Sang Won; Han, Seungoh; Seo, Jun Ho; Kim, Young Mok; Kang, Moon Sik; Min, Nam Ki; Choi, Woo Beom; Sung, Man Young

2009-05-01

A liquid lens based on the electrowetting phenomenon was designed to be cylindrical to minimize dead area. The lens was fabricated with microelectromechanical-system (MEMS) technology using silicon thin film and wafer bonding processes. A multiple dielectric layer comprising Teflon, silicon nitride, and thermal oxide was formed on the cylinder wall. With a change of 11 Vrms in the applied bias, the lens module, including the fabricated liquid lens, showed a focal length change of approximately 166 mm. A capsule endoscope was assembled, including the lens module, and was successfully used to take images of a pig colon at various focal lengths.

In Situ Electrochemical Synthesis of Oriented and Defect-Free AEL Molecular-Sieve Films Using Ionic Liquids.

PubMed

Yu, Tongwen; Chu, Wenling; Cai, Rui; Liu, Yanchun; Yang, Weishen

2015-10-26

Simply preparing oriented and defect-free molecular-sieve films have been a long-standing challenge both in academia and industry. Most of the early works focus on the careful and multiple controls of the seeds layer or synthesis conditions. Herein, we report a one-step in situ electrochemical ionothermal method that combines a controllable electric field with ionic liquids. We demonstrate that an in-plane oriented and defect-free AEL (one molecular-sieve framework type) molecular-sieve film was obtained using an Al electrode as the Al source. The excellent corrosion-resistant performance of the film makes this technology promising in multiple applications, such as anti-corrosion coatings. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Observation of surface layering in a nonmetallic liquid

NASA Astrophysics Data System (ADS)

Mo, Haiding; Evmenenko, Guennadi; Kewalramani, Sumit; Kim, Kyungil; Dutta, Pulak; Ehrlich, Steven

2006-03-01

Non-monotonic density profiles (layers) have previously been observed at the free surfaces of many metallic liquids, but not in isotropic dielectric liquids. Whether the presence of an electron gas is necessary for surface layering has been the subject of debate. Until recently, MD simulations have suggested that layering at free liquid interface may be a generic phenomenon and is not limited to the metallic liquids^1. The theories predict that if normal liquids can be cooled down to temperatures low enough, layering structure should be observed experimentally. However, this is difficult for most molecular liquids because these liquids freeze well above the temperature necessary for observing the layering structure. By studying the surface structure of liquid TEHOS (tetrakis(2-ethylhexoxy)silane), which combines relatively low freezing point and high boiling point compared to that of most molecular liquids, we have observed the evidence of layering at the free interface of liquid TEHOS using x-ray reflectivity. When cooled to T/Tc 0.25 (well above the bulk freezing point, Tc is the critical temperature of TEHOS), the surface roughness drops sharply and density oscillations appear near the surface. Lateral ordering of the surface layers is liquid-like, just as at liquid metal surfaces. 1. E. Chac'on and P. Tarazona, Phys. Rev. Lett. 91 166103-1 (2003)

A Variational Method to Retrieve the Extinction Profile in Liquid Clouds Using Multiple Field-of-View Lidar

NASA Technical Reports Server (NTRS)

Pounder, Nicola L.; Hogan, Robin J.; Varnai, Tamas; Battaglia, Alessandro; Cahalan, Robert F.

2011-01-01

While liquid clouds playa very important role in the global radiation budget, it's been very difficult to remotely determine their internal cloud structure. Ordinary lidar instruments (similar to radars but using visible light pulses) receive strong signals from such clouds, but the information is limited to a thin layer near the cloud boundary. Multiple field-of-view (FOV) lidars offer some new hope as they are able to isolate photons that were scattered many times by cloud droplets and penetrated deep into a cloud before returning to the instrument. Their data contains new information on cloud structure, although the lack of fast simulation methods made it challenging to interpret the observations. This paper describes a fast new technique that can simulate multiple-FOV lidar signals and can even estimate the way the signals would change in response to changes in cloud properties-an ability that allows quick refinements in our initial guesses of cloud structure. Results for a hypothetical airborne three-FOV lidar suggest that this approach can help determine cloud structure for a deeper layer in clouds, and can reliably determine the optical thickness of even fairly thick liquid clouds. The algorithm is also applied to stratocumulus observations by the 8-FOV airborne "THOR" lidar. These tests demonstrate that the new method can determine the depth to which a lidar provides useful information on vertical cloud structure. This work opens the way to exploit data from spaceborne lidar and radar more rigorously than has been possible up to now.

SINDA/FLUINT Stratified Tank Modeling for Cryrogenic Propellant Tanks

NASA Technical Reports Server (NTRS)

Sakowski, Barbara

2014-01-01

A general purpose SINDA/FLUINT (S/F) stratified tank model was created to simulate self-pressurization and axial jet TVS; Stratified layers in the vapor and liquid are modeled using S/F lumps.; The stratified tank model was constructed to permit incorporating the following additional features:, Multiple or singular lumps in the liquid and vapor regions of the tank, Real gases (also mixtures) and compressible liquids, Venting, pressurizing, and draining, Condensation and evaporation/boiling, Wall heat transfer, Elliptical, cylindrical, and spherical tank geometries; Extensive user logic is used to allow detailed tailoring - Don't have to rebuilt everything from scratch!!; Most code input for a specific case is done through the Registers Data Block:, Lump volumes are determined through user input:; Geometric tank dimensions (height, width, etc); Liquid level could be input as either a volume percentage of fill level or actual liquid level height

Sinda/Fluint Stratfied Tank Modeling

NASA Technical Reports Server (NTRS)

Sakowski, Barbara A.

2014-01-01

A general purpose SINDA/FLUINT (S/F) stratified tank model was created and used to simulate the Ksite1 LH2 liquid self-pressurization tests as well as axial jet mixing within the liquid region of the tank. The S/F model employed the use of stratified layers, i.e. S/F lumps, in the vapor ullage as well as in the liquid region. The model was constructed to analyze a general purpose stratified tank that could incorporate the following features: Multiple or singular lumps in the liquid and vapor regions of the tank, Real gases (also mixtures) and compressible liquids, Venting, pressurizing, and draining, Condensation and evaporation/boiling, Wall heat transfer, Elliptical, cylindrical, and spherical tank geometries. Extensive user logic was used to allow for tailoring of the above features to specific cases. Most of the code input for a specific case could be done through the Registers Data Block.

Evidence of unfrozen liquids and seismic anisotropy at the base of the polar ice sheets

NASA Astrophysics Data System (ADS)

Wittlinger, Gérard; Farra, Véronique

2015-03-01

We analyze seismic data from broadband stations located on the Antarctic and Greenland ice sheets to determine polar ice seismic velocities. P-to-S converted waves at the ice/rock interface and inside the ice sheets and their multiples (the P-receiver functions) are used to estimate in-situ P-wave velocity (Vp) and P-to-S velocity ratio (Vp/Vs) of polar ice. We find that the polar ice sheets have a two-layer structure; an upper layer of variable thickness (about 2/3 of the total thickness) with seismic velocities close to the standard ice values, and a lower layer of approximately constant thickness with standard Vp but ∼25% smaller Vs. The lower layer ceiling corresponds approximately to the -30 °C isotherm. Synthetic modeling of P-receiver functions shows that strong seismic anisotropy and low vertical S velocity are needed in the lower layer. The seismic anisotropy results from the preferred orientation of ice crystal c-axes toward the vertical. The low vertical S velocity may be due to the presence of unfrozen liquids resulting from premelting at grain joints and/or melting of chemical solutions buried in the ice. The strongly preferred ice crystal orientation fabric and the unfrozen fluids may facilitate polar ice sheet basal flow.

Effect of Liquid Viscosity on Dispersion of Quasi-Lamb Waves in an Elastic-Layer-Viscous-Liquid-Layer System

NASA Astrophysics Data System (ADS)

Guz, A. N.; Bagno, A. M.

2017-07-01

The dispersion curves are constructed and propagation of quasi-Lamb waves are studied for wide range of frequencies based on the Navier -Stokes three-dimensional linearized equations for a viscous liquid and linear equations of the classical theory of elasticity for an elastic layer. For a thick liquid layer, the effect of the viscosity of the liquid and the thickness of elastic and liquid layers on the phase velocities and attenuation coefficients of quasi-Lamb modes is analyzed. It is shown that in the case of a thick liquid layer for all modes, there are elastic layers of certain thickness with minimal effect of liquid viscosity on the phase velocities and attenuation coefficients of modes. It is also discovered that for some modes, there are both certain thicknesses and certain ranges of thickness where the effect of liquid viscosity on the phase velocities and attenuation coefficients of these modes is considerable. We ascertain that liquid viscosity promotes decrease of the penetration depth of the lowest quasi-Lamb mode into the liquid. The developed approach and the obtained results make it possible to ascertain for wave processes the limits of applicability of the model of ideal compressible fluid. Numerical results in the form of graphs are adduced and analyzed.

Investigations on laser hard tissue ablation under various environments

NASA Astrophysics Data System (ADS)

Kang, H. W.; Oh, J.; Welch, A. J.

2008-06-01

The purpose of this study was to investigate the effect of liquid environments upon laser bone ablation. A long-pulsed Er,Cr:YSGG laser was employed to ablate bovine bone tibia at various radiant exposures under dry, wet (using water or perfluorocarbon) and spray environmental conditions. Energy loss by the application of liquid during laser irradiation was evaluated, and ablation performance for all conditions was quantitatively measured by optical coherence tomography (OCT). Microscope images were also used to estimate thermal side effects in tissue after multiple-pulse ablation. Wet using water and spray conditions equally attenuated the 2.79 µm wavelength laser beam. Higher transmission efficiency was obtained utilizing a layer of perfluorocarbon. Dry ablation exhibited severe carbonization due to excessive heat accumulation. Wet condition using water resulted in similar ablation volume to the dry case without carbonization. The perfluorocarbon layer produced the largest ablation volume but some carbonization due to the poor thermal conductivity. Spray induced clean cutting with slightly reduced efficiency. Liquid-assisted ablation provided significant beneficial effects such as augmented material removal and cooling/cleaning effects during laser osteotomy.

Ion distributions in electrolyte confined by multiple dielectric interfaces

NASA Astrophysics Data System (ADS)

Jing, Yufei; Zwanikken, Jos W.; Jadhao, Vikram; de La Cruz, Monica

2014-03-01

The distribution of ions at dielectric interfaces between liquids characterized by different dielectric permittivities is crucial to nanoscale assembly processes in many biological and synthetic materials such as cell membranes, colloids and oil-water emulsions. The knowledge of ionic structure of these systems is also exploited in energy storage devices such as double-layer super-capacitors. The presence of multiple dielectric interfaces often complicates computing the desired ionic distributions via simulations or theory. Here, we use coarse-grained models to compute the ionic distributions in a system of electrolyte confined by two planar dielectric interfaces using Car-Parrinello molecular dynamics simulations and liquid state theory. We compute the density profiles for various electrolyte concentrations, stoichiometric ratios and dielectric contrasts. The explanations for the trends in these profiles and discuss their effects on the behavior of the confined charged fluid are also presented.

Histopathological analysis of the therapeutic response to cryotherapy with liquid nitrogen in patients with multiple actinic keratosis.

PubMed

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

2015-01-01

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

Ternary liquid mixtures control the multiplicity, shape and internal structure of emulsion droplets

NASA Astrophysics Data System (ADS)

Haase, Martin F.; Brujic, Jasna

2014-03-01

It is important to control the shape, internal structure and stability of emulsion droplets for drug delivery, biochemical assays, and the design of materials with novel physical properties. Successful methods involve the mechanical manipulation of the flow of oil in water using complex microfluidic devices to make multiple emulsions with a sequential introduction of specific reactants. Instead, here we show how the thermodynamics of immiscible liquid mixtures tailor emulsions using a single dripping instability. For example, the initial composition and choice of surfactant govern the multiplicity of concentric alternating oil and water layers inside the droplets. Stabilizing ternary droplets using nanoparticles gives rise to a plethora of shapes whose geometry is defined by the deformability of the shell and the flow rate. Another option is to incorporate lipids to the multiple emulsion droplet, which form vesicles upon expulsion of the inner water droplets. Depending on the number of initial water droplets, these vesicles eventually form complex hollow topologies, which can be used as junctions or scaffolds for the self-assembly of colloidal particles in the future.

The Mixed-Phase Arctic Cloud Experiment (M-PACE)

NASA Technical Reports Server (NTRS)

Verlinde, J.; Harrington, J. Y.; McFarquhar, G. M.; Yannuzzi, V. T.; Avramov, A.; Greenberg, S.; Johnson, N.; Zhang, G.; Poellot, M. R.; Mather, J. H.;

Surface order in cold liquids: X-ray reflectivity studies of dielectric liquids and comparison to liquid metals

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chattopadhyay, S.; Ehrlich, S.; Uysal, A.

2010-05-17

Oscillatory surface-density profiles layers have previously been reported in several metallic liquids, one dielectric liquid, and in computer simulations of dielectric liquids. We have now seen surface layers in two other dielectric liquids, pentaphenyl trimethyl trisiloxane, and pentavinyl pentamethyl cyclopentasiloxane. These layers appear below T?285 K and T?130 K, respectively; both thresholds correspond to T/Tc?0.2 where Tc is the liquid-gas critical temperature. All metallic and dielectric liquid surfaces previously studied are also consistent with the existence of this T/Tc threshold, first indicated by the simulations of Chacon et al. The layer width parameters, determined using a distorted-crystal fitting model, followmore » common trends as functions of Tc for both metallic and dielectric liquids.« less

Phase-partitioning in mixed-phase clouds - An approach to characterize the entire vertical column

NASA Astrophysics Data System (ADS)

Kalesse, H.; Luke, E. P.; Seifert, P.

2017-12-01

The characterization of the entire vertical profile of phase-partitioning in mixed-phase clouds is a challenge which can be addressed by synergistic profiling measurements with ground-based polarization lidars and cloud radars. While lidars are sensitive to small particles and can thus detect supercooled liquid (SCL) layers, cloud radar returns are dominated by larger particles (like ice crystals). The maximum lidar observation height is determined by complete signal attenuation at a penetrated optical depth of about three. In contrast, cloud radars are able to penetrate multiple liquid layers and can thus be used to expand the identification of cloud phase to the entire vertical column beyond the lidar extinction height, if morphological features in the radar Doppler spectrum can be related to the existence of SCL. Relevant spectral signatures such as bimodalities and spectral skewness can be related to cloud phase by training a neural network appropriately in a supervised learning scheme, with lidar measurements functioning as supervisor. The neural network output (prediction of SCL location) derived using cloud radar Doppler spectra can be evaluated with several parameters such as liquid water path (LWP) detected by microwave radiometer (MWR) and (liquid) cloud base detected by ceilometer or Raman lidar. The technique has been previously tested on data from Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) instruments in Barrow, Alaska and is in this study utilized for observations from the Leipzig Aerosol and Cloud Remote Observations System (LACROS) during the Analysis of the Composition of Clouds with Extended Polarization Techniques (ACCEPT) field experiment in Cabauw, Netherlands in Fall 2014. Comparisons to supercooled-liquid layers as classified by CLOUDNET are provided.

Thermocapillary convection in two immiscible liquid layers with free surface

NASA Technical Reports Server (NTRS)

Doi, Takao; Koster, Jean N.

1993-01-01

Thermocapillary convection is studied in two immiscible liquid layers with one free surface, one liquid/liquid interface, and differential heating applied parallel to the interfaces. An analytical solution is introduced for infinite horizontal layers. The defining parameter for the flow pattern is lambda, the ratio of the temperature coefficient of the interfacial tension to that of the surface tension. Four different flow patterns exist under zero gravity conditions. 'Halt' conditions which halt the fluid motion in the lower encapsulated liquid layer have been found. A numerical experiment is carried out to study effects of vertical end walls on the double layer convection in a 2D cavity. The halt condition obtained from the analytical study is found to be valid in the limit of small Reynolds numbers. The flow in the encapsulated liquid layer can be suppressed substantially.

Surface order in cold liquids: X-ray reflectivity studies of dielectric liquids and comparison to liquid metals

NASA Astrophysics Data System (ADS)

Chattopadhyay, Sudeshna; Uysal, Ahmet; Stripe, Benjamin; Ehrlich, Steven; Karapetrova, Evguenia A.; Dutta, Pulak

2010-05-01

Oscillatory surface-density profiles (layers) have previously been reported in several metallic liquids, one dielectric liquid, and in computer simulations of dielectric liquids. We have now seen surface layers in two other dielectric liquids, pentaphenyl trimethyl trisiloxane, and pentavinyl pentamethyl cyclopentasiloxane. These layers appear below T˜285K and T˜130K , respectively; both thresholds correspond to T/Tc˜0.2 where Tc is the liquid-gas critical temperature. All metallic and dielectric liquid surfaces previously studied are also consistent with the existence of this T/Tc threshold, first indicated by the simulations of Chacón [Phys. Rev. Lett. 87, 166101 (2001)]. The layer width parameters, determined using a distorted-crystal fitting model, follow common trends as functions of Tc for both metallic and dielectric liquids.

Chembio extraction on a chip by nanoliter droplet ejection.

PubMed

Yu, Hongyu; Kwon, Jae Wan; Kim, Eun Sok

2005-03-01

This paper describes a novel liquid separation technique for chembio extraction by an ultrasonic nanoliter-liquid-droplet ejector built on a PZT sheet. This technique extracts material from an aqueous two-phase system (ATPS) in a precise amount through digital control of the number of nanoliter droplets, without any mixing between the two liquids in the ATPS. The ultrasonic droplet ejector uses an acoustic streaming effect produced by an acoustic beam focused on the liquid surface, and ejects liquid droplets only from the liquid surface without disturbing most of the liquid below the surface. This unique characteristic of the focused acoustic beam is perfect (1) for separating a top-layer liquid (from the bulk of liquid) that contains particles of interest or (2) for recovering a top-layer liquid that has different phase from a bottom-layer liquid. Three kinds of liquid extraction are demonstrated with the ultrasonic droplet ejector: (1) 16 microl of top layer in Dextran-polyethylene glycol-water ATPS (aqueous two-phase system) is recovered within 20 s; (2) micron sized particles that float on water surface are ejected out with water droplets; and (3) oil layer on top of water is separated out.

Long-Wavelength Instability in Marangoni Convection

NASA Technical Reports Server (NTRS)

VanHook, Stephen J.; Schatz, Michael F.; Swift, Jack B.; McCormick, W. D.; Swinney, Harry L.

1996-01-01

Our experiments in thin liquid layers (approximately 0.1 mm thick) heated from below reveal a well-defined long-wavelength instability: at a critical temperature difference across the layer, the depth of the layer in the center of the cell spontaneously decreases until the liquid-air interface ruptures and a dry spot forms. The onset of this critical instability occurs at a temperature difference across the liquid layer that is 35% smaller than that predicted in earlier theoretical studies of a single layer model. Our analysis of a two-layer model yields predictions in accord with the observations for liquid layer depths greater than or equal to 0.15 mm, but for smaller depths there is an increasing difference between our predictions and observations (the difference is 25% for a layer 0.06 mm thick). In microgravity environments the long-wavelength instability observed in our terrestrial experiments is expected to replace cellular convection as the primary instability in thick as well as thin liquid layers heated quasistatically from below.

Infrared laboratory studies of synthetic planetary atmospheres

NASA Technical Reports Server (NTRS)

Williams, D.

1977-01-01

Topics covered include: the broadening of individual lines in the CO fundamental by various gases; total band absorptance as a function of absorber thickness and total effect pressure at various temperatures for bands of CO and N2O; nitric acid vapor content in the region of the ozone layer; optical properties of solid NH3; HSO4 concentration in Venus clouds; Burch's law of multiplicative transmittance for mixing absorbing gases when their lines are broadened by helium and hydrogen; ling strength and self-broadening parameters in the v3 fundamental of CO2 and N2O; optical constants of liquid ammonia, liquid methane, saturated hydrocarbons, ammonium hydride and ammonium salts.

Vortex Flows in the Liquid Layer and Droplets on a Vibrating Flexible Plate

NASA Astrophysics Data System (ADS)

Aleksandrov, Vladimir; Kopysov, Sergey; Tonkov, Leonid

2018-02-01

In certain conditions, in the layers and droplets of a liquid on a vibrating rectangular flexible plate, vortex flows are formed simultaneously with the excitation of capillary oscillations on the free surface of the liquid layers and droplets. Capillary oscillations in the form of two-dimensional standing waves form Faraday ripples on the free surface of the liquid layer. On the surface of the vibrating droplets, at the excitation of capillary oscillations a light spot reflected from a spotlight source moves along a trajectory in the form of a Lissajous figure observed with a microscope. When vortex flows visualized with graphite microparticles appear in the layer and droplets of a transparent liquid, the trajectory of the light spot on the layer and droplet surface is a two-dimensional trajectory in the form of an ellipse or a saddle. This indicates that the generation of the vortex flows in a liquid at vibrations is due to capillary oscillations in the orthogonally related directions. In the liquid layer and droplets on the surface of the flexible plate, the vibrations of which are generated by bending vibrations, the vortex flows appear due to the plate vibrations and the capillary oscillations of the surface of a layer or a droplet of the liquid. On the free surface of the liquid, the capillary waves, which are parametrically excited by the plate bending vibrations, are additionally modulated by the same bending vibrations in the transverse direction.

Method for improving the durability of ion insertion materials

DOEpatents

Lee, Se-Hee; Tracy, C. Edwin; Cheong, Hyeonsik M.

2002-01-01

The invention provides a method of protecting an ion insertion material from the degradative effects of a liquid or gel-type electrolyte material by disposing a protective, solid ion conducting, electrically insulating, layer between the ion insertion layer and the liquid or gel-type electrolyte material. The invention further provides liquid or gel-type electrochemical cells having improved durability having a pair of electrodes, a pair of ion insertion layers sandwiched between the pair of electrodes, a pair of solid ion conducting layers sandwiched between the ion insertion layers, and a liquid or gel-type electrolyte material disposed between the solid ion conducting layers, where the solid ion conducting layer minimizes or prevents degradation of the faces of the ion insertion materials facing the liquid or gel-type electrolyte material. Electrochemical cells of this invention having increased durability include secondary lithium batteries and electrochromic devices.

Study on dynamic deformation synchronized measurement technology of double-layer liquid surfaces

NASA Astrophysics Data System (ADS)

Tang, Huiying; Dong, Huimin; Liu, Zhanwei

2017-11-01

Accurate measurement of the dynamic deformation of double-layer liquid surfaces plays an important role in many fields, such as fluid mechanics, biomechanics, petrochemical industry and aerospace engineering. It is difficult to measure dynamic deformation of double-layer liquid surfaces synchronously for traditional methods. In this paper, a novel and effective method for full-field static and dynamic deformation measurement of double-layer liquid surfaces has been developed, that is wavefront distortion of double-wavelength transmission light with geometric phase analysis (GPA) method. Double wavelength lattice patterns used here are produced by two techniques, one is by double wavelength laser, and the other is by liquid crystal display (LCD). The techniques combine the characteristics such as high transparency, low reflectivity and fluidity of liquid. Two color lattice patterns produced by laser and LCD were adjusted at a certain angle through the tested double-layer liquid surfaces simultaneously. On the basis of the refractive indexes difference of two transmitted lights, the double-layer liquid surfaces were decoupled with GPA method. Combined with the derived relationship between phase variation of transmission-lattice patterns and out-of plane heights of two surfaces, as well as considering the height curves of the liquid level, the double-layer liquid surfaces can be reconstructed successfully. Compared with the traditional measurement method, the developed method not only has the common advantages of the optical measurement methods, such as high-precision, full-field and non-contact, but also simple, low cost and easy to set up.

Nanoporous carbon supercapacitors in an ionic liquid: a computer simulation study.

PubMed

Shim, Youngseon; Kim, Hyung J

2010-04-27

Supercapacitors composed of carbon nanotube (CNT) micropores in the room-temperature ionic liquid (RTIL) 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI+BF4(-)) are studied via molecular dynamics (MD)computer simulations. It is found that the distribution of RTIL ions inside the micropore varies significantly with the pore size. Internal solvation of small (6,6) and (7,7) CNTs with an electrified interior wall is effected almost exclusively via counterions. Surprisingly, these counterions, even though they all have the same charge, lead to a charge density characterized by multiple layers with alternating signs. This intriguing feature is attributed to the extended nature of RTIL ion charge distributions, which result in charge separation through preferential orientation inside the electrified nanotubes. In the case of larger (10,10) and (15,15) CNTs, counterions and coions develop multilayer solvation structures. The specific capacitance normalized to the pore surface area is found to increase as the CNT diameter decreases from (15,15) to (7,7). As the pore size further reduces from (6,6) to(5,5), however, the specific capacitance diminishes rapidly. These findings are in excellent agreement with recent experiments with carbon-based materials. A theoretical model based on multiple charge layers is proposed to understand both the MD and experimental results.

Micromachined quartz crystal resonator arrays for bioanalytical applications

NASA Astrophysics Data System (ADS)

Kao, Ping

This work presents the design, fabrication and investigation of high frequency quartz crystal resonator arrays and their application for analyzing interfacial layers and sensing purposes. An 8-pixel micromachined quartz crystal resonator array with a fundamental resonance frequency of ˜66 MHz has been fabricated, tested and used in this work. One dimensional model for the characterization of resonator behavior for single or multiple viscoelastic layers under liquid ambient are developed by continuum mechanics approach as well as using an equivalent electrical admittance analysis approach. The investigation of thin interfacial layer between solid (electrode) and liquid phases are reported in terms of the improved resolution of viscoelasitc characteristics of adsorbed layer arising from the use of high frequency resonators. Analyzed layers include globular proteins layer under phosphate buffer solution (PBS) with molecular weights spanning three orders of magnitude, multilayers of avidin and biotin labeled bovine albumin under PBS and diffuse double layer induced by DC bias under 0.5 M sulfuric acid solution. The second half of the dissertation focuses on biosensing applications of quartz resonator arrays. The selective functionalization of 3,3'-Dithiobis (sulfosuccinimidylpropionate) (DTSSP) by physical masking method was first used for specifically detecting avidin molecules. The selective immobilization of thiol modified single stranded DNA probes via electrochemical methods was used for the specific detection of Respiratory Syncytial Virus (RSV) G-gene. The work demonstrates that micromachined quartz crystal resonator arrays could be a powerful analytical tool of investigating interfacial region and can be readily configured as biosenors that can be used for label-free, quantitative assays using extremely small volumes of analytes.

Generation of three-dimensional multiple spheroid model of olfactory ensheathing cells using floating liquid marbles

PubMed Central

Vadivelu, Raja K.; Ooi, Chin H.; Yao, Rebecca-Qing; Tello Velasquez, Johana; Pastrana, Erika; Diaz-Nido, Javier; Lim, Filip; Ekberg, Jenny A. K.; Nguyen, Nam-Trung; St John, James A.

2015-01-01

We describe a novel protocol for three-dimensional culturing of olfactory ensheathing cells (OECs), which can be used to understand how OECs interact with other cells in three dimensions. Transplantation of OECs is being trialled for repair of the paralysed spinal cord, with promising but variable results and thus the therapy needs improving. To date, studies of OEC behaviour in a multicellular environment have been hampered by the lack of suitable three-dimensional cell culture models. Here, we exploit the floating liquid marble, a liquid droplet coated with hydrophobic powder and placed on a liquid bath. The presence of the liquid bath increases the humidity and minimises the effect of evaporation. Floating liquid marbles allow the OECs to freely associate and interact to produce OEC spheroids with uniform shapes and sizes. In contrast, a sessile liquid marble on a solid surface suffers from evaporation and the cells aggregate with irregular shapes. We used floating liquid marbles to co-culture OECs with Schwann cells and astrocytes which formed natural structures without the confines of gels or bounding layers. This protocol can be used to determine how OECs and other cell types associate and interact while forming complex cell structures. PMID:26462469

Generation of three-dimensional multiple spheroid model of olfactory ensheathing cells using floating liquid marbles

NASA Astrophysics Data System (ADS)

Vadivelu, Raja K.; Ooi, Chin H.; Yao, Rebecca-Qing; Tello Velasquez, Johana; Pastrana, Erika; Diaz-Nido, Javier; Lim, Filip; Ekberg, Jenny A. K.; Nguyen, Nam-Trung; St John, James A.

2015-10-01

We describe a novel protocol for three-dimensional culturing of olfactory ensheathing cells (OECs), which can be used to understand how OECs interact with other cells in three dimensions. Transplantation of OECs is being trialled for repair of the paralysed spinal cord, with promising but variable results and thus the therapy needs improving. To date, studies of OEC behaviour in a multicellular environment have been hampered by the lack of suitable three-dimensional cell culture models. Here, we exploit the floating liquid marble, a liquid droplet coated with hydrophobic powder and placed on a liquid bath. The presence of the liquid bath increases the humidity and minimises the effect of evaporation. Floating liquid marbles allow the OECs to freely associate and interact to produce OEC spheroids with uniform shapes and sizes. In contrast, a sessile liquid marble on a solid surface suffers from evaporation and the cells aggregate with irregular shapes. We used floating liquid marbles to co-culture OECs with Schwann cells and astrocytes which formed natural structures without the confines of gels or bounding layers. This protocol can be used to determine how OECs and other cell types associate and interact while forming complex cell structures.

Interaction of Multiple Particles with a Solidification Front: From Compacted Particle Layer to Particle Trapping.

PubMed

Saint-Michel, Brice; Georgelin, Marc; Deville, Sylvain; Pocheau, Alain

2017-06-13

The interaction of solidification fronts with objects such as particles, droplets, cells, or bubbles is a phenomenon with many natural and technological occurrences. For an object facing the front, it may yield various fates, from trapping to rejection, with large implications regarding the solidification pattern. However, whereas most situations involve multiple particles interacting with each other and the front, attention has focused almost exclusively on the interaction of a single, isolated object with the front. Here we address experimentally the interaction of multiple particles with a solidification front by performing solidification experiments of a monodisperse particle suspension in a Hele-Shaw cell with precise control of growth conditions and real-time visualization. We evidence the growth of a particle layer ahead of the front at a close-packing volume fraction, and we document its steady-state value at various solidification velocities. We then extend single-particle models to the situation of multiple particles by taking into account the additional force induced on an entering particle by viscous friction in the compacted particle layer. By a force balance model this provides an indirect measure of the repelling mean thermomolecular pressure over a particle entering the front. The presence of multiple particles is found to increase it following a reduction of the thickness of the thin liquid film that separates particles and front. We anticipate the findings reported here to provide a relevant basis to understand many complex solidification situations in geophysics, engineering, biology, or food engineering, where multiple objects interact with the front and control the resulting solidification patterns.

Antimycobacterial, antimicrobial, and biocompatibility properties of para-aminosalicylic acid with zinc layered hydroxide and Zn/Al layered double hydroxide nanocomposites

PubMed Central

Saifullah, Bullo; El Zowalaty, Mohamed E; Arulselvan, Palanisamy; Fakurazi, Sharida; Webster, Thomas J; Geilich, Benjamin M; Hussein, Mohd Zobir

2014-01-01

The treatment of tuberculosis by chemotherapy is complicated due to multiple drug prescriptions, long treatment duration, and adverse side effects. We report here for the first time an in vitro therapeutic effect of nanocomposites based on para-aminosalicylic acid with zinc layered hydroxide (PAS-ZLH) and zinc-aluminum layered double hydroxides (PAS-Zn/Al LDH), against mycobacteria, Gram-positive bacteria, and Gram-negative bacteria. The nanocomposites demonstrated good antimycobacterial activity and were found to be effective in killing Gram-positive and Gram-negative bacteria. A biocompatibility study revealed good biocompatibility of the PAS-ZLH nanocomposites against normal human MRC-5 lung cells. The para-aminosalicylic acid loading was quantified with high-performance liquid chromatography analysis. In summary, the present preliminary in vitro studies are highly encouraging for further in vivo studies of PAS-ZLH and PAS-Zn/Al LDH nanocomposites to treat tuberculosis. PMID:25114509

Biosensor properties of SOI nanowire transistors with a PEALD Al{sub 2}O{sub 3} dielectric protective layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Popov, V. P., E-mail: popov@isp.nsc.ru; Ilnitskii, M. A.; Zhanaev, E. D.

2016-05-15

The properties of protective dielectric layers of aluminum oxide Al{sub 2}O{sub 3} applied to prefabricated silicon-nanowire transistor biochips by the plasma enhanced atomic layer deposition (PEALD) method before being housed are studied depending on the deposition and annealing modes. Coating the natural silicon oxide with a nanometer Al{sub 2}O{sub 3} layer insignificantly decreases the femtomole sensitivity of biosensors, but provides their stability in bioliquids. In deionized water, transistors with annealed aluminum oxide are closed due to the trapping of negative charges of <(1–10) × 10{sup 11} cm{sup −2} at surface states. The application of a positive potential to the substratemore » (V{sub sub} > 25 V) makes it possible to eliminate the negative charge and to perform multiple measurements in liquid at least for half a year.« less

Methods of Fabricating a Layer of Metallic Glass-Based Material Using Immersion and Pouring Techniques

NASA Technical Reports Server (NTRS)

Hofmann, Douglas (Inventor)

2015-01-01

Systems and methods in accordance with embodiments of the invention implement layers of metallic glass-based materials. In one embodiment, a method of fabricating a layer of metallic glass includes: applying a coating layer of liquid phase metallic glass to an object, the coating layer being applied in a sufficient quantity such that the surface tension of the liquid phase metallic glass causes the coating layer to have a smooth surface; where the metallic glass has a critical cooling rate less than 1000 K/s; and cooling the coating layer of liquid phase metallic glass to form a layer of solid phase metallic glass.

One-step production of multilayered microparticles by tri-axial electro-flow focusing

NASA Astrophysics Data System (ADS)

Si, Ting; Feng, Hanxin; Li, Yang; Luo, Xisheng; Xu, Ronald

2014-03-01

Microencapsulation of drugs and imaging agents in the same carrier is of great significance for simultaneous detection and treatment of diseases. In this work, we have developed a tri-axial electro-flow focusing (TEFF) device using three needles with a novel concentric arrangement to one-step form multilayered microparticles. The TEFF process can be characterized as a multi-fluidic compound cone-jet configuration in the core of a high-speed coflowing gas stream under an axial electric field. The tri-axial liquid jet eventually breaks up into multilayered droplets. To validate the method, the effect of main process parameters on characteristics of the cone and the jet has been studied experimentally. The applied electric field can dramatically promote the stability of the compound cone and enhance the atomization of compound liquid jets. Microparticles with both three-layer, double-layer and single-layer structures have been obtained. The results show that the TEFF technique has great benefits in fabricating multilayered microparticles at smaller scales. This method will be able to one-step encapsulate multiple therapeutic and imaging agents for biomedical applications such as multi-modal imaging, drug delivery and biomedicine.

Advances in NIF Shock Timing Experiments

NASA Astrophysics Data System (ADS)

Robey, Harry

2012-10-01

Experiments are underway to tune the shock timing of capsule implosions on the National Ignition Facility (NIF). These experiments use a modified cryogenic hohlraum geometry designed to precisely match the performance of ignition hohlraums. The targets employ a re-entrant Au cone to provide optical access to multiple shocks as they propagate in the liquid deuterium-filled capsule interior. The strength and timing of all four shocks is diagnosed with VISAR (Velocity Interferometer System for Any Reflector). Experiments are now routinely conducted in a mirrored keyhole geometry, which allows for simultaneous diagnosis of the shock timing at both the hohlraum pole and equator. Further modifications are being made to improve the surrogacy to ignition hohlraums by replacing the standard liquid deuterium (D2) capsule fill with a deuterium-tritium (DT) ice layer. These experiments will remove any possible surrogacy difference between D2 and DT as well as incorporate the physics of shock release from the ice layer, which is absent in current experiments. Experimental results and comparisons with numerical simulation are presented.

Applying a uniform layer of disinfectant by wiping.

PubMed

Cooper, D W

2000-01-01

Disinfection or sterilization often requires applying a film of liquid to a surface, frequently done by using a wiper as the applicator. The wiper must not only hold a convenient amount of liquid, it must deposit it readily and uniformly. Contact time is critical to disinfection efficacy. Evaporation can limit the contact time. To lengthen the contact time, thickly applied layers are generally preferred. The thickness of such layers can be determined by using dyes or other tracers, as long as the tracers do not significantly affect the liquid's surface tension and viscosity and thus do not affect the thickness of the applied layer. Alternatively, as done here, the thickness of the layer can be inferred from the weight loss of the wiper. Results are reported of experiments on thickness of the layers applied under various conditions. Near saturation, hydrophilic polyurethane foam wipers gave layers roughly 10 microns thick, somewhat less than expected from hydrodynamic theory, but more than knitted polyester or woven cotton. Wipers with large liquid holding capacity, refilled often, should produce more nearly uniform layers. Higher pressures increase saturation in the wiper, tending to thicken the layer, but higher pressures also force liquid from the interface, tending to thin the layer, so the net result could be thicker or thinner layers, and there is likely to be an optimal pressure.

Transient liquid phase ceramic bonding

DOEpatents

Glaeser, Andreas M.

1994-01-01

Ceramics are joined to themselves or to metals using a transient liquid phase method employing three layers, one of which is a refractory metal, ceramic or alloy. The refractory layer is placed between two metal layers, each of which has a lower melting point than the refractory layer. The three layers are pressed between the two articles to be bonded to form an assembly. The assembly is heated to a bonding temperature at which the refractory layer remains solid, but the two metal layers melt to form a liquid. The refractory layer reacts with the surrounding liquid and a single solid bonding layer is eventually formed. The layers may be designed to react completely with each other and form refractory intermetallic bonding layers. Impurities incorporated into the refractory metal may react with the metal layers to form refractory compounds. Another method for joining ceramic articles employs a ceramic interlayer sandwiched between two metal layers. In alternative embodiments, the metal layers may include sublayers. A method is also provided for joining two ceramic articles using a single interlayer. An alternate bonding method provides a refractory-metal oxide interlayer placed adjacent to a strong oxide former. Aluminum or aluminum alloys are joined together using metal interlayers.

Origin of Fe-Ti Oxide Mineralization in the Middle Paleoproterozoic Elet'ozero Syenite-Gabbro Intrusive Complex (Northern Karelia, Russia)

NASA Astrophysics Data System (ADS)

Sharkov, E. V.; Chistyakov, A. V.; Shchiptsov, V. V.; Bogina, M. M.; Frolov, P. V.

2018-03-01

Magmatic oxide mineralization widely developed in syenite-gabbro intrusive complexes is an important Fe and Ti resource. However, its origin is hotly debatable. Some researchers believe that the oxide ores were formed through precipitation of dense Ti-magnetite in an initial ferrogabbroic magma (Bai et al., 2012), whereas others consider them as a product of immiscible splitting of Fe-rich liquid during crystallization of Fe-Ti basaltic magma (Zhou et al., 2013). We consider this problem with a study of the Middle Paleoproterozoic (2086 ± 30 Ma) Elet'ozero Ti-bearing layered intrusive complex in northern Karelia (Baltic Shield). The first ore-bearing phase of the complex is mainly made up of diverse ferrogabbros, with subordinate clinopyroxenites and peridotites. Fe-Ti oxides (magnetite, Ti-magnetite, and ilmenite) usually account for 10-15 vol %, reaching 30-70% in ore varieties. The second intrusive phase is formed by alkaline and nepheline syenites. Petrographical, mineralogical, and geochemical data indicate that the first phase of the intrusion was derived from a moderately alkaline Fe-Ti basaltic melt, while the parental melt of the second phase was close in composition to alkaline trachyte. The orebodies comprise disseminated and massive ores. The disseminated Fe-Ti oxide ores make up lenses and layers conformable to general layering. Massive ores occur in subordinate amounts as layers and lenses, as well as cross-cutting veins. Elevated Nb and Ta contents in Fe-Ti oxides makes it possible to consider them complex ores. It is shown that the Fe-Ti oxide mineralization is related to the formation of a residual (Fe,Ti)-rich liquid, which lasted for the entire solidification history of the first intrusive phase. The liquid originated through multiple enrichment of Fe and Ti in the crystallization zone of the intrusion owing to the following processes: (1) precipitation of silicate minerals in the crystallization zone with a corresponding increase in the Fe and Ti contents in an interstitial melt; and (2) periodic accumulation of the residual melt in front of this zone. Unlike liquid immiscibility leading to melt splitting into two phases, this liquid dissolved the residual components of the melt. Correspondingly, such an Fe-rich liquid has unusual properties and requires further study.

Gravitational instability of thin gas layer between two thick liquid layers

NASA Astrophysics Data System (ADS)

Pimenova, A. V.; Goldobin, D. S.

2016-12-01

We consider the problem of gravitational instability (Rayleigh-Taylor instability) of a horizontal thin gas layer between two liquid half-spaces (or thick layers), where the light liquid overlies the heavy one. This study is motivated by the phenomenon of boiling at the surface of direct contact between two immiscible liquids, where the rate of the "break-away" of the vapor layer growing at the contact interface due to development of the Rayleigh-Taylor instability on the upper liquid-gas interface is of interest. The problem is solved analytically under the assumptions of inviscid liquids and viscous weightless vapor. These assumptions correspond well to the processes in real systems, e.g., they are relevant for the case of interfacial boiling in the system water- n-heptane. In order to verify the results, the limiting cases of infinitely thin and infinitely thick gas layers were considered, for which the results can be obviously deduced from the classical problem of the Rayleigh-Taylor instability. These limiting cases are completely identical to the well-studied cases of gravity waves at the liquidliquid and liquid-gas interfaces. When the horizontal extent of the system is long enough, the wavenumber of perturbations is not limited from below, and the system is always unstable. The wavelength of the most dangerous perturbations and the rate of their exponential growth are derived as a function of the layer thickness. The dependence of the exponential growth rate on the gas layer thickness is cubic.

Method and apparatus for processing algae

DOEpatents

Chew, Geoffrey; Reich, Alton J.; Dykes, Jr., H. Waite; Di Salvo, Roberto

2012-07-03

Methods and apparatus for processing algae are described in which a hydrophilic ionic liquid is used to lyse algae cells. The lysate separates into at least two layers including a lipid-containing hydrophobic layer and an ionic liquid-containing hydrophilic layer. A salt or salt solution may be used to remove water from the ionic liquid-containing layer before the ionic liquid is reused. The used salt may also be dried and/or concentrated and reused. The method can operate at relatively low lysis, processing, and recycling temperatures, which minimizes the environmental impact of algae processing while providing reusable biofuels and other useful products.

Magnetic Phase Diagram of α-RuCl3

NASA Astrophysics Data System (ADS)

Sears, Jennifer; Kim, Young-June; Zhao, Yang; Lynn, Jeffrey

The layered honeycomb material α-RuCl3 is thought to possess unusual magnetic interactions including a strong bond-dependent Kitaev term, offering a potential opportunity to study a material near a well understood spin liquid phase. Although this material orders magnetically at low temperatures and is thus not a realization of a Kitaev spin liquid, it does show a broad continuum of magnetic excitations reminiscent of that expected for the spin liquid phase. It has also been proposed that a magnetic field could destabilize the magnetic order in this material and induce a transition into a spin liquid phase. Low temperature magnetization and specific heat measurements in this material have suggested a complex magnetic phase diagram with multiple unidentified magnetic phases present at low temperature. This has provided motivation for our work characterizing the magnetic transitions and phase diagram in α-RuCl3. I will present detailed bulk measurements combined with magnetic neutron diffraction measurements to map out the phase diagram and identify the various phases present.

Versatile alignment layer method for new types of liquid crystal photonic devices

DOE Office of Scientific and Technical Information (OSTI.GOV)

Finnemeyer, V.; Bryant, D.; Lu, L.

2015-07-21

Liquid crystal photonic devices are becoming increasingly popular. These devices often present a challenge when it comes to creating a robust alignment layer in pre-assembled cells. In this paper, we describe a method of infusing a dye into a microcavity to produce an effective photo-definable alignment layer. However, previous research on such alignment layers has shown that they have limited stability, particularly against subsequent light exposure. As such, we further describe a method of utilizing a pre-polymer, infused into the microcavity along with the liquid crystal, to provide photostability. We demonstrate that the polymer layer, formed under ultraviolet irradiation ofmore » liquid crystal cells, has been effectively localized to a thin region near the substrate surface and provides a significant improvement in the photostability of the liquid crystal alignment. This versatile alignment layer method, capable of being utilized in devices from the described microcavities to displays, offers significant promise for new photonics applications.« less

Mathematic modeling of the method of measurement relative dielectric permeability

NASA Astrophysics Data System (ADS)

Plotnikova, I. V.; Chicherina, N. V.; Stepanov, A. B.

2018-05-01

The method of measuring relative permittivity’s and the position of the interface between layers of a liquid medium is considered in the article. An electric capacitor is a system consisting of two conductors that are separated by a dielectric layer. It is mathematically proven that at any given time it is possible to obtain the values of the relative permittivity in the layers of the liquid medium and to determine the level of the interface between the layers of the two-layer liquid. The estimation of measurement errors is made.

Stable azodye photo-alignment layer for liquid crystal devices achieved by "turning off" dye photosensitivity

NASA Astrophysics Data System (ADS)

McGinty, C.; Finnemeyer, V.; Reich, R.; Clark, H.; Berry, S.; Bos, P.

2017-11-01

We have previously proposed a low cost, versatile process for stabilizing azodye photo-alignment layers for liquid crystal devices by utilizing a surface localized reactive mesogen (RM) layer. The RM is applied by dissolving the monomer in a liquid crystal material prior to filling the cell. In this paper, we show the significant effect of azodye layer thickness on the long term stability of these alignment layers when exposed to polarized light. We demonstrate, surprisingly, that thin azodye layers (˜3 nm) provide improved stability over thicker (˜40 nm) layers. Using this process, we show cells which have been stable to exposure with polarized light through one month. Additionally, we demonstrate the use of a photo-alignment layer to align the liquid crystals that afterwards can be rendered insensitive to polarized light. This was accomplished by using the process described above with the additional step of eliminating the photosensitivity of the azodye layer through photo-bleaching; the result is an RM alignment layer that will be stable when exposed to polarized light in the dye absorption band.

Drop impact on liquid film: dynamics of interfacial gas layer

NASA Astrophysics Data System (ADS)

Tang, Xiaoyu; Saha, Abhishek; Law, Chung K.; Sun, Chao

2016-11-01

Drop impacting liquid film is commonly observed in many processes including inkjet printing and thermal sprays. Owing to the resistance from the interfacial gas layer trapped between the drop and film surface, impact may not always result in coalescence; and as such investigating the behavior of the interfacial gas layer is important to understand the transition between bouncing and merging outcomes. The gas layer is, however, not easily optically accessible due to its microscopic scale and curved interfaces. We report the measurement of this critical gas layer thickness between two liquid surfaces using high-speed color interferometry capable of measuring micron and submicron thicknesses. The complete gas layer dynamics for the bouncing cases can be divided into two stages: the approaching stage when the drop squeezes the gas layer at the beginning of the impact, and the rebounding stage when the drop retracts and rebounds from the liquid film. The approaching stage is found to be similar across wide range of conditions studied. However, for the rebounding stage, with increase of liquid film thickness, the evolution of gas layer changes dramatically, displaying a non-monotonic behavior. Such dynamics is analyzed in lights of various competing timescales.

A polarization-independent liquid crystal phase modulation using polymer-network liquid crystal with orthogonal alignment layers

NASA Astrophysics Data System (ADS)

Chen, Ming-Syuan; Lin, Wei-Chih; Tsou, Yu-Shih; Lin, Yi-Hsin

2012-10-01

A polarization-independent liquid crystal (LC) phase modulation using polymer-network liquid crystals with orthogonal alignments layers (T-PNLC) is demonstrated. T-PNLC consists of three layers. LC directors in the two layers near glass substrates are orthogonal to each other. In the middle layer, LC directors are perpendicular to the glass substrate. The advantages of such T-PNLC include polarizer-free, larger phase shift (~0.4π rad) than the residual phase type (<0.05π rad), and low operating voltage (< 30Vrms). It does not require bias voltage for avoiding scattering because the refractive index of liquid crystals matches that of polymers. The phase shift of T-PNLC is affected by the cell gap and the curing voltages. The potential applications are laser beam steering, spatial light modulators and electrically tunable micro-lens arrays.

Effect of surface wave propagation in a four-layered oceanic crust model

NASA Astrophysics Data System (ADS)

Paul, Pasupati; Kundu, Santimoy; Mandal, Dinbandhu

2017-12-01

Dispersion of Rayleigh type surface wave propagation has been discussed in four-layered oceanic crust. It includes a sandy layer over a crystalline elastic half-space and over it there are two more layers—on the top inhomogeneous liquid layer and under it a liquid-saturated porous layer. Frequency equation is obtained in the form of determinant. The effects of the width of different layers as well as the inhomogeneity of liquid layer, sandiness of sandy layer on surface waves are depicted and shown graphically by considering all possible case of the particular model. Some special cases have been deduced, few special cases give the dispersion equation of Scholte wave and Stoneley wave, some of which have already been discussed elsewhere.

Uniform hydrogen fuel layers for inertial fusion targets by microgravity

NASA Technical Reports Server (NTRS)

Parks, P. B.; Fagaly, Robert L.

1994-01-01

A critical concern in the fabrication of targets for inertial confinement fusion (ICF) is ensuring that the hydrogenic (D(sub 2) or DT) fuel layer maintains spherical symmetry. Solid layered targets have structural integrity, but lack the needed surface smoothness. Liquid targets are inherently smooth, but suffer from gravitationally induced sagging. One method to reduce the effective gravitational field environment is freefall insertion into the target chamber. Another method to counterbalance field gravitational force is to use an applied magnetic field combined with a gradient field to induce a magnetic dipole force on the liquid fuel layer. Based on time dependent calculations of the dynamics of the liquid fuel layer in microgravity environments, we show that it may be possible to produce a liquid layered ICF target that satisfies both smoothness and symmetry requirements.

Topological defects in electric double layers of ionic liquids at carbon interfaces

DOE PAGES

Black, Jennifer M.; Okatan, Mahmut Baris; Feng, Guang; ...

2015-06-07

The structure and properties of the electrical double layer in ionic liquids is of interest in a wide range of areas including energy storage, catalysis, lubrication, and many more. Theories describing the electrical double layer for ionic liquids have been proposed, however a full molecular level description of the double layer is lacking. To date, studies have been predominantly focused on ion distributions normal to the surface, however the 3D nature of the electrical double layer in ionic liquids requires a full picture of the double layer structure not only normal to the surface, but also in plane. Here wemore » utilize 3D force mapping to probe the in plane structure of an ionic liquid at a graphite interface and report the direct observation of the structure and properties of topological defects. The observation of ion layering at structural defects such as step-edges, reinforced by molecular dynamics simulations, defines the spatial resolution of the method. Observation of defects allows for the establishment of the universality of ionic liquid behavior vs. separation from the carbon surface and to map internal defect structure. In conclusion, these studies offer a universal pathway for probing the internal structure of topological defects in soft condensed matter on the nanometer level in three dimensions.« less

Microfluidic droplet trapping array as nanoliter reactors for gas-liquid chemical reaction.

PubMed

Zhang, Qingquan; Zeng, Shaojiang; Qin, Jianhua; Lin, Bingcheng

2009-09-01

This article presents a simple method for trapping arrays of droplets relying on the designed microstructures of the microfluidic device, and this has been successfully used for parallel gas-liquid chemical reaction. In this approach, the trapping structure is composed of main channel, lateral channel and trapping region. Under a negative pressure, array droplets can be generated and trapped in the microstructure simultaneously, without the use of surfactant and the precise control of the flow velocity. By using a multi-layer microdevice containing the microstructures, single (pH gradient) and multiple gas-liquid reactions (metal ion-NH3 complex reaction) can be performed in array droplets through the transmembrane diffusion of the gas. The droplets with quantitative concentration gradient can be formed by only replacing the specific membrane. The established method is simple, robust and easy to operate, demonstrating the potential of this device for droplet-based high-throughput screening.

Combustion theory for liquids with a free surface. 3: Special problems

NASA Technical Reports Server (NTRS)

Milkov, S. N.; Sukhov, G. S.; Yarin, L. P.

1986-01-01

Two special problems concerning the combustion of liquids with a free surface, i.e., flame quenching during the mixing of a burning liquid inside a container and liquid burnout from a porous layer, are analyzed using a quasi-one-dimensional model. The critical parameters corresponding to the quenching of a burning fluid with a free surface are determined. Determinations are also made of the limiting pressure gradients corresponding to the transition from the combustion mode where the liquid evaporates from the surface of a porous layer to the mode where the phase transition surface lies inside the porous layer.

Some bifurcation routes to chaos of thermocapillary convection in two-dimensional liquid layers of finite extent

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, K., E-mail: likai@imech.ac.cn; University of Chinese Academy of Sciences, Beijing 100190; Xun, B.

2016-05-15

As a part of the preliminary studies for the future space experiment (Zona-K) in the Russian module of the International Space Station, some bifurcation routes to chaos of thermocapillary convection in two-dimensional liquid layers filled with 10 cSt silicone oil have been numerically studied in this paper. As the laterally applied temperature difference is raised, variations in the spatial structure and temporal evolution of the thermocapillary convection and a complex sequence of transitions are observed. The results show that the finite extent of the liquid layer significantly influences the tempo-spatial evolution of the thermocapillary convection. Moreover, the bifurcation route ofmore » the thermocapillary convection changes very sensitively by the aspect ratio of the liquid layer. With the increasing Reynolds number (applied temperature difference), the steady thermocapillary convection experiences two consecutive transitions from periodic oscillatory state to quasi-periodic oscillatory state with frequency-locking before emergence of chaotic convection in a liquid layer of aspect ratio 14.25, and the thermocapillary convection undergoes period-doubling cascades leading to chaotic convection in a liquid layer of aspect ratio 13.0.« less

Marangoni-Benard Convection in a Evaporating Liquid Thin Layer

NASA Technical Reports Server (NTRS)

Chai, An-Ti; Zhang, Nengli

1996-01-01

Marangoni-Benard convection in evaporating liquid thin layers has been investigated through flow visualization and temperature profile measurement. Twelve liquids, namely ethyl alcohol, methanol, chloroform, acetone, cyclohexane, benzine, methylene chloride, carbon tetrachloride, ethyl acetate, n-pentane, silicone oil (0.65 cSt.), and freon-113, were tested and convection patterns in thin layers of these samples were observed. Comparison among these tested samples shows that some liquids are sensitive to surface contamination from aluminum powder but some are not. The latter is excellent to be used for the investigation of surface-tension driven convection through visualization using the tracer. Two sample liquids, alcohol and freon-113 were particularly selected for systematic study. It was found that the wavelength of Benard cells would not change with thickness of the layer when it evaporates at room temperature. Special attention was focused on cases in which a liquid layer was cooled from below, and some interesting results were obtained. Convection patterns were recorded during the evaporation process and the patterns at certain time frame were compared. Benard cells were observed in thin layers with a nonlinear temperature profile and even with a zero or positive temperature gradient. Wavelength of the cells was found to increase as the evaporation progressed.

Optical control of graphene plasmon using liquid crystal layer 29K New One

DTIC Science & Technology

2017-03-01

AFRL-AFOSR-UK-TR-2017-0014 Optical control of graphene plasmon using liquid crystal layer 29K New One Viktor Yuriyovych Reshetnyak SCIENCE AND... plasmon using liquid crystal layer 29K New One 5a.  CONTRACT NUMBER 5b.  GRANT NUMBER STCU-P652 5c.  PROGRAM ELEMENT NUMBER 61102F 6. AUTHOR(S) Viktor...the basic research and establishes possible optical ways to control the surface plasmon polariton in graphene layer. A system comprises the graphene

Processes that generate and deplete liquid water and snow in thin midlevel mixed-phase clouds

NASA Astrophysics Data System (ADS)

Smith, Adam J.; Larson, Vincent E.; Niu, Jianguo; Kankiewicz, J. Adam; Carey, Lawrence D.

2009-06-01

This paper uses a numerical model to investigate microphysical, radiative, and dynamical processes in mixed-phase altostratocumulus clouds. Three cloud cases are chosen for study, each of which was observed by aircraft during the fifth or ninth Complex Layered Cloud Experiment (CLEX). These three clouds are numerically modeled using large-eddy simulation (LES). The observed and modeled clouds consist of a mixed-phase layer with a quasi-adiabatic profile of liquid, and a virga layer below that consists of snow. A budget of cloud (liquid) water mixing ratio is constructed from the simulations. It shows that large-scale ascent/descent, radiative cooling/heating, turbulent transport, and microphysical processes are all significant. Liquid is depleted indirectly via depositional growth of snow (the Bergeron-Findeisen process). This process is more influential than depletion of liquid via accretional growth of snow. Also constructed is a budget of snow mixing ratio, which turns out to be somewhat simpler. It shows that snow grows by deposition in and below the liquid (mixed-phase) layer, and sublimates in the remainder of the virga region below. The deposition and sublimation are balanced primarily by sedimentation, which transports the snow from the growth region to the sublimation region below. In our three clouds, the vertical extent of the virga layer is influenced more by the profile of saturation ratio below the liquid (mixed-phase) layer than by the mixing ratio of snow at the top of the virga layer.

Surface Layering Near Room Temperature in a Nonmetallic Liquid

NASA Astrophysics Data System (ADS)

Chattopadhyay, Sudeshna; Stripe, Benjamin; Shively, Patrick; Evmenenko, Geunnadi; Dutta, Pulak; Ehrlich, Steven; Mo, Haiding

2009-03-01

Oscillatory density profiles (layers) have been observed at the free surfaces of many liquid metals at and above room temperature [1]. A surface-layered state has been previously reported only in one dielectric liquid, tetrakis(2-ethylhexoxy)silane (TEHOS), and only at lower temperatures [2]. We have used x-ray reflectivity to study a molecular liquid, pentaphenyl trimethyl trisiloxane. Below T˜ 267K (well above the freezing point for this liquid), density oscillations appear at the surface. This liquid has a higher Tc (˜1200K) than TEHOS (˜950K), so that layers appear at T/Tc 0.2 in both cases. Our results indicate that surface order is a universal phenomenon in both metallic and dielectric liquids, and that the underlying physics is likely to be the same since layers always appear at T<˜0.2Tc as theoretically predicted [3] [3pt] REFERENCES: [0pt] [1]. e.g. O. M. Magnussen et al., Phys. Rev. Lett. 74, 4444 (1995) [0pt] [2]. H. Mo et al. Phys. Rev. Lett. 96, 096107 (2006); Phys. Rev. B 76, 024206 (2007) [0pt] [3]. e.g. E. Chac'on et al., Phys. Rev. Lett. 87, 166101 (2001)

Acoustic wave-driven oxidized liquid metal-based energy harvester

NASA Astrophysics Data System (ADS)

Jeon, Jinpyo; Chung, Sang Kug; Lee, Jeong-Bong; Doo, Seok Joo; Kim, Daeyoung

2018-06-01

We report an oxidized liquid metal droplet-based energy harvester that converts acoustic energy into electrical energy by modulating an electrical double layer that originates from the deformation of the oxidized liquid metal droplet. Gallium-based liquid metal alloy has been developed for various applications owing to the outstanding material properties, such as its high electrical conductivity (metallic property) and unlimited deformability (liquid property). In this study, we demonstrated energy harvesting using an electrical double layer between the acoustic wave-modulated liquid metal droplet and two electrodes. The proposed energy harvester consisted of top and bottom electrodes covered with the dielectric layer and a Gallium-based liquid metal droplet placed between the electrodes. When we applied an external bias voltage and acoustic wave to the proposed device, the contact area between the liquid metal droplet and the electrodes changed, leading to the variation of the capacitance in the electrical double layer and the generation of electrical output current. Using the proposed energy harvester, the maximum output current of 41.2 nA was generated with an applied acoustic wave of 30 Hz. In addition, we studied the relationships between the maximum output current and a variety of factors, such as the size of the liquid metal droplet, the thickness of the hydrophobic layer, and the distance between the top and bottom electrode plates.

Effect of anisotropy on defect mode peculiarities in chiral liquid crystals

NASA Astrophysics Data System (ADS)

Gevorgyan, A. H.; Oganesyan, K. B.

2018-01-01

The effect of anisotropy on defect mode peculiarities in cholesteric liquid crystals is investigated. The light transmission through the cholesteric liquid crystal layer with an anisotropic layer defect inside is solved by Ambartsumian’s layer addition modified method. Two cases are considered. In the first case, it is assumed that the defect layer is non-absorbing, and the effect of refraction anisotropy on the reflection, relative photonic density of states and the total field intensity produced in the defect layer are studied. In the second case, the defect layer is assumed to be isotropic for refraction and anisotropic for absorption, and the influence of defect layer absorption anisotropy on reflection, absorption, relative photonic density of states and the total field intensity produced in the defect layer are investigated.

a Fractal Permeability Model Coupling Boundary-Layer Effect for Tight Oil Reservoirs

NASA Astrophysics Data System (ADS)

Wang, Fuyong; Liu, Zhichao; Jiao, Liang; Wang, Congle; Guo, Hu

A fractal permeability model coupling non-flowing boundary-layer effect for tight oil reservoirs was proposed. Firstly, pore structures of tight formations were characterized with fractal theory. Then, with the empirical equation of boundary-layer thickness, Hagen-Poiseuille equation and fractal theory, a fractal torturous capillary tube model coupled with boundary-layer effect was developed, and verified with experimental data. Finally, the parameters influencing effective liquid permeability were quantitatively investigated. The research results show that effective liquid permeability of tight formations is not only decided by pore structures, but also affected by boundary-layer distributions, and effective liquid permeability is the function of fluid type, fluid viscosity, pressure gradient, fractal dimension, tortuosity fractal dimension, minimum pore radius and maximum pore radius. For the tight formations dominated with nanoscale pores, boundary-layer effect can significantly reduce effective liquid permeability, especially under low pressure gradient.

A Parallel Spectroscopic Method for Examining Dynamic Phenomena on the Millisecond Time Scale

PubMed Central

Snively, Christopher M.; Chase, D. Bruce; Rabolt, John F.

2009-01-01

An infrared spectroscopic technique based on planar array infrared (PAIR) spectroscopy has been developed that allows the acquisition of spectra from multiple samples simultaneously. Using this technique, it is possible to acquire spectra over a spectral range of 950–1900cm−1 with a temporal resolution of 2.2ms. The performance of this system was demonstrated by determining the shear-induced orientational response of several low molecular weight liquid crystals. Five different liquid crystals were examined in combination with five different alignment layers, and both primary and secondary screens were demonstrated. Implementation of this high throughput PAIR technique resulted in a reduction in acquisition time as compared to both step-scan and ultra-rapid-scanning FTIR spectroscopy. PMID:19239197

Alternative design of pipe sleeve for liquid removal mechanism in mortar slab layer

NASA Astrophysics Data System (ADS)

Nazri, W. M. H. Wan; Anting, N.; Lim, A. J. M. S.; Prasetijo, J.; Shahidan, S.; Din, M. F. Md; Anuar, M. A. Mohd

2017-11-01

Porosity is one of the mortar’s characteristics that can cause problems, especially in the room space that used high amount of water, such as bathrooms. Waterproofing is one of the technology that normally used to minimize this problem which is preventing deep penetration of liquid water or moisture into underlying concrete layers. However, without the proper mechanism to remove liquid water and moisture from mortar system, waterproofing layer tends to be damaged after a long period of time by the static formation of liquid water and moisture at mortar layer. Thus, a solution has been proposed to drain out water that penetrated into the mortar layer. This paper introduces a new solution using a Modified Pipe Sleeve (MPS) that installed at the mortar layer. The MPS has been designed considering the percentage surface area of the pipe sleeve that having contact with mortar layer (2%, 4%, 6%, 8% and 10%) with angle of holes of 60°. Infiltration test and flow rate test have been conducted to identify the effectiveness of the MPS in order to drain out liquid water or moisture from the mortar layer. In this study shows that, MPS surface area 10%, angled 60°, function effectively as a water removal compared to other design.

Wetting of cholesteric liquid crystals.

PubMed

Silvestre, Nuno M; Figueirinhas Pereira, Maria Carolina; Bernardino, Nelson R; Telo da Gama, Margarida M

2016-02-01

We investigate theoretically the wetting properties of cholesteric liquid crystals at a planar substrate. If the properties of substrate and of the interface are such that the cholesteric layers are not distorted, the wetting properties are similar to those of a nematic liquid crystal. If, on the other hand, the anchoring conditions force the distortion of the liquid crystal layers the wetting properties are altered, the free cholesteric-isotropic interface is non-planar and there is a layer of topological defects close to the substrate. These deformations can either promote or hinder the wetting of the substrate by a cholesteric, depending on the properties of the cholesteric liquid crystal.

Long-wavelength Instability in Surface-tension-driven Bénard Convection

NASA Astrophysics Data System (ADS)

van Hook, Stephen J.

1997-03-01

Laboratory experiments and numerical simulations reveal that a liquid layer heated from below and possessing a free upper surface can undergo a long-wavelength deformational instability that causes rupture of the interface.(S. J. VanHook, M. F. Schatz, W. D. McCormick, J. B. Swift, and H. L. Swinney, Phys. Rev. Lett.) 75, 4397 (1995). Depending on the depth and thermal conductivity of the liquid and the overlying gas layer, the interface can rupture downwards and form a dry spot or rupture upwards and form a high spot. This long-wavelength instability competes with the formation of Bénard hexagons for thin or viscous liquid layers, or for liquid layers in microgravity.

Liquid-phase growth of few-layered graphene on sapphire substrates using SiC micropowder source

NASA Astrophysics Data System (ADS)

Maruyama, Takahiro; Yamashita, Yutaka; Saida, Takahiro; Tanaka, Shin-ichiro; Naritsuka, Shigeya

2017-06-01

We demonstrated direct synthesis of graphene films consisting of a few layers (few-layered graphene) on sapphire substrates by liquid-phase growth (LPG), using liquid Ga as the melt and SiC micropowder as the source material. When the dissolution temperature was above 700 °C, almost all Si atoms of SiC diffused into the Ga melt and only carbon atoms remained at the interface beneath the liquid Ga. Above 800 °C, X-ray photoelectron spectra showed that most of the remaining carbon was graphitized. When the dissolution temperature was 1000 °C, Raman spectra showed that few-layered graphene films grew on the sapphire substrates.

Synthetic Polymers at Interfaces: Monodisperse Emulsions Multiple Emulsions and Liquid Marbles

NASA Astrophysics Data System (ADS)

Sun, Guanqing

The adsorption of polymeric materials at interfaces is an energetically favorable process which is investigated in much diversified fields, such as emulsions, bubbles, foams, liquid marbles. Pickering emulsion, which is emulsion stabilized by solid particles has been investigated for over one century and preparation of Pickering emulsion with narrow size distribution is crucial for both the theoretical study of the stabilization mechanism and practical application, such as templated fabrication of colloidosomes. The precise control over the size and functionality of polymer latices allows the preparation of monodisperse Pickering emulsions with desired sizes through SPG membrane emulsification at rather rapid rate compared to microfludic production. Double or multiple emulsions have long been investigated but its rapid destabilization has always been a major obstacle in applying them into practical applications. The modern living polymerization techniques allow us to prepare polymers with designed structure of block copolymers which makes it possible to prepare ultra-stable multiple emulsions. The precise tuning of the ratio of hydrophobic part over the hydrophilic can unveil the stabilization mechanism. Liquid marble is a new type of materials of which liquid droplets are coated by dry particles. The coating of an outer layer of dry particles renders the liquid droplets non-sticky at solid surface which is useful in transportation of small amount of liquid without leakage at extreme low friction force. The property of liquid marbles relies largely on the stabilizers and the drying condition of polymeric latices is shown to have great influence on the property of liquid marbles. Firstly, an introduction to the interfacial and colloidal science with special attention to topics on emulsions, multiple emulsion and liquid marbles is given in Chapter 1. The unique features of an interface and a discussion on the definition of colloids are introduced prior to the discussion of emulsion stabilization and preparation. A historical review of multiple emulsions is presented subsequently and the stability mechanism is discussed in details with regard to the transportation kinetics of small molecules through the separating membrane of double emulsions. The principle, property and applications of liquid marbles are then summarized. Secondly, the preparation of monodisperse Pickering emulsions stabilized by soft PNIPAM-co-MAA microgels through SPG membrane emulsification is described. The influence of the membrane pore size, pH of the particle dispersion, particle size and the operating parameters of the membrane emulsification device on the size of the emulsion droplets was investigated systematically. The improvement in monodispersity of the emulsion droplets allows us to measure the release profiles of a small molecular dye and a larger nanoparticle through the colloidosomes. It is further demonstrated that the preparation of monodisperse emulsions stabilized by other types of soft particles allows us control the stability of the emulsion with a pH trigger and improved biocompatibility. Thirdly, the preparation of multiple emulsions stabilized by a special designed PEG-b-PS diblock copolymer with desired hydrophobicity by one-step method was presented. The ultra-stability of the as-obtained multiple emulsions was ascribed to the effective steric stabilization of the two interfaces with different polymer configurations at the interfaces. A series of diblock copolymer with increasing PS chain length was then synthesized to investigate the influence of asymmetry ratio on the type of emulsions prepared. It is found that the diblock copolymers with the asymmetry ratio of approximately 1 had the highest power to stabilize multiple emulsions. The multiple emulsions were demonstrated to be a promising platform for controlled release. In the end, particle-stabilized water-in-air liquid marbles were investigated. PSco-MAA nanoparticles synthesized from surfactant-free emulsion polymerization were proved to be effective liquid marble stabilizers. The influence of drying conditions on the properties of liquid marbles was investigated through a macroscopic way. The pH value of the particle dispersion, which influences the protonation states of the particles before freeze-drying, has a profound influence on the property of the stabilized liquid marbles. A brief comment to the future of work of these investigated systems is delivered in the last part.

Experimental study of oblique impact between dry spheres and liquid layers

NASA Astrophysics Data System (ADS)

Ma, Jiliang; Liu, Daoyin; Chen, Xiaoping

2013-09-01

Liquid addition is common in industrial fluidization-based processes. A detailed understanding of collision mechanics of particles with liquid layers is helpful to optimize these processes. The normal impact with liquid has been studied extensively; however, the studies on oblique impact with liquid are scarce. In this work, experiments are conducted to trace Al2O3 spheres obliquely impacting on a surface covered by liquid layers, in which the free-fall spheres are disturbed initially by a horizontal gas flow. The oblique impact exhibits different rebound behaviors from normal collision due to the occurrence of strong rotation. The normal and tangential restitution coefficients (en and et) and liquid bridge rupture time (trup) are analyzed. With increase in liquid layer thickness and viscosity, en and et decline, and trup increases. With increase in tangential velocity, et decreases first and then increases, whereas en remains nearly unchanged, and trup decreases constantly. A modified Stokes number is proposed to further explore the relation between restitution coefficients and the impact parameters. Finally, an analysis of energy dissipation shows that the contact deformation and liquid phase are the two main sources of total energy dissipation. Unexpectedly, the dissipative energy caused by the liquid phase is independent of tangential velocity.

A naked eye refractive index sensor with a visible multiple peak metamaterial absorber.

PubMed

Ma, Heli; Song, Kun; Zhou, Liang; Zhao, Xiaopeng

2015-03-26

We report a naked eye refractive index sensor with a visible metamaterial absorber. The visible metamaterial absorber consisting of a silver dendritic/dielectric/metal structure shows multiple absorption peaks. By incorporating a gain material (rhodamine B) into the dielectric layer, the maximal magnitude of the absorption peak can be improved by about 30%. As the metamaterial absorber is sensitive to the refractive index of glucose solutions, it can function as a sensor that quickly responds to variations of the refractive index of the liquid. Meanwhile, since the response is presented via color changes, it can be clearly observed by the naked eyes. Further experiments have confirmed that the sensor can be used repeatedly.

Terraced spreading of simple liquids on solid surfaces

NASA Technical Reports Server (NTRS)

Yang, Ju-Xing; Koplik, Joel; Banavar, Jayanth R.

1992-01-01

We have studied the spreading of liquid drops on a solid surface by molecular-dynamics simulations of coexisting three-phase Lennard-Jones systems of liquid, vapor, and solid. We consider both spherically symmetric atoms and diatomic molecules, and a range of interaction strengths. As the attraction between liquid and solid increases we observe a smooth transition in spreading regimes, from partial to complete to terraced wetting. In the terraced case, where distinct monomolecular layers spread with different velocities, the layers are ordered but not solid, with substantial molecular diffusion both within and between layers. The quantitative behavior resembles recent experimental findings, but the detailed dynamics differ. In particular, the layers exhibit an unusual spreading law, where their radii vary in time as R-squared approximately equal to log10t, which disagrees with experiments on polymeric liquids as well as recent calculations.

Control of liquid crystal molecular orientation using ultrasound vibration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Taniguchi, Satoki; Wave Electronics Research Center, Doshisha University, 1-3 Tataramiyakodani, Kyotanabe, Kyoto 610-0321; Koyama, Daisuke

2016-03-07

We propose a technique to control the orientation of nematic liquid crystals using ultrasound and investigate the optical characteristics of the oriented samples. An ultrasonic liquid crystal cell with a thickness of 5–25 μm and two ultrasonic lead zirconate titanate transducers was fabricated. By exciting the ultrasonic transducers, the flexural vibration modes were generated on the cell. An acoustic radiation force to the liquid crystal layer was generated, changing the molecular orientation and thus the light transmission. By modulating the ultrasonic driving frequency and voltage, the spatial distribution of the molecular orientation of the liquid crystals could be controlled. The distributionmore » of the transmitted light intensity depends on the thickness of the liquid crystal layer because the acoustic field in the liquid crystal layer is changed by the orientational film.« less

Simulation of Layered Magma Chambers.

ERIC Educational Resources Information Center

Cawthorn, Richard Grant

1991-01-01

The principles of magma addition and liquid layering in magma chambers can be demonstrated by dissolving colored crystals. The concepts of density stratification and apparent lack of mixing of miscible liquids is convincingly illustrated with hydrous solutions at room temperature. The behavior of interstitial liquids in "cumulus" piles…

Photonic band gaps from a stack of right- and left-hand chiral photonic crystal layers.

PubMed

Gevorgyan, A H

2012-02-01

In the present paper we investigated the optical properties of a stack of right- and left- hand chiral photonic crystal layers. The problem is solved by Ambartsumian's layer addition modified method. We investigated the reflection spectra peculiarities of this system and showed that in contrast to a single cholesteric liquid crystal (CLC) layer this system has multiple photonic band gaps (PBGs) (at light normal incidence). We showed that this system has unique polarization properties, particularly the eigenpolarizations (EPs) of the system are degenerated (i.e., the two EPs coincide) for an even number of layers and, in contrast to ordinary gyrotropic systems, the polarization plane rotation decreases if the system thickness is increased, the rotation sign depends on the first sublayer chirality sign, the system is very sensitive to the change of the sublayer number in the system, etc. We also investigated the influence of sublayer thicknesses, incidence angle, the sublayer local dielectric anisotropies, the sublayer helix pitches on the reflection peculiarities, and other optical parameters of the system. © 2012 American Physical Society

Leaping shampoo glides on a lubricating air layer

NASA Astrophysics Data System (ADS)

Lee, S.; Li, E. Q.; Marston, J. O.; Bonito, A.; Thoroddsen, S. T.

2013-06-01

When a stream of shampoo is fed onto a pool in one's hand, a jet can leap sideways or rebound from the liquid surface in an intriguing phenomenon known as the Kaye effect. Earlier studies have debated whether non-Newtonian effects are the underlying cause of this phenomenon, making the jet glide on top of a shear-thinning liquid layer, or whether an entrained air layer is responsible. Herein we show unambiguously that the jet slides on a lubricating air layer. We identify this layer by looking through the pool liquid and observing its rupture into fine bubbles. The resulting microbubble sizes suggest this air layer is of submicron thickness. This thickness estimate is also supported by the tangential deceleration of the jet during the rebounding.

Leaping shampoo glides on a lubricating air layer.

PubMed

Lee, S; Li, E Q; Marston, J O; Bonito, A; Thoroddsen, S T

2013-06-01

When a stream of shampoo is fed onto a pool in one's hand, a jet can leap sideways or rebound from the liquid surface in an intriguing phenomenon known as the Kaye effect. Earlier studies have debated whether non-Newtonian effects are the underlying cause of this phenomenon, making the jet glide on top of a shear-thinning liquid layer, or whether an entrained air layer is responsible. Herein we show unambiguously that the jet slides on a lubricating air layer. We identify this layer by looking through the pool liquid and observing its rupture into fine bubbles. The resulting microbubble sizes suggest this air layer is of submicron thickness. This thickness estimate is also supported by the tangential deceleration of the jet during the rebounding.

Twisted nematic liquid crystal cells with rubbed poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) films for active polarization control of terahertz waves

NASA Astrophysics Data System (ADS)

Sasaki, Tomoyuki; Okuyama, Hiroki; Sakamoto, Moritsugu; Noda, Kohei; Okamoto, Hiroyuki; Kawatsuki, Nobuhiro; Ono, Hiroshi

2017-04-01

We fabricated a terahertz (THz) polarization converter using a twisted nematic (TN) liquid crystal (LC) cell. Poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) films coated on quartz glass substrates were used as electrode layers in the TN LC cell. The PEDOT/PSS films were rubbed unidirectionally using a rayon cloth to align the nematic LC, thereby also serving as an alignment layer. The azimuthal surface anchoring strength of the PEDOT/PSS films was measured to be 5 × 10-4 J/m2 using the Néel wall method, which is similar to that of typical polymeric alignment layers. The optical constants of the PEDOT/PSS film in the THz range were also characterized using the Drude-Smith model, and the results indicated that the PEDOT/PSS films could be used both as transparent electrodes in the THz range and as alignment layers for the LC. The electro-optical properties of the fabricated TN LC cell were also investigated using a polarized visible laser and THz time-domain spectroscopic system. In particular, the transmission spectra and polarization conversion property of the TN LC cell in the THz range were theoretically analyzed based on a stratified model that considers optical anisotropy, absorption, and multiple interference. This work substantiates the advantages of TN LC cells with rubbed PEDOT/PSS films useful for THz polarization converters with electrical tunability.

Ionic Liquids as Electrolytes for Electrochemical Double-Layer Capacitors: Structures that Optimize Specific Energy.

PubMed

Mousavi, Maral P S; Wilson, Benjamin E; Kashefolgheta, Sadra; Anderson, Evan L; He, Siyao; Bühlmann, Philippe; Stein, Andreas

2016-02-10

Key parameters that influence the specific energy of electrochemical double-layer capacitors (EDLCs) are the double-layer capacitance and the operating potential of the cell. The operating potential of the cell is generally limited by the electrochemical window of the electrolyte solution, that is, the range of applied voltages within which the electrolyte or solvent is not reduced or oxidized. Ionic liquids are of interest as electrolytes for EDLCs because they offer relatively wide potential windows. Here, we provide a systematic study of the influence of the physical properties of ionic liquid electrolytes on the electrochemical stability and electrochemical performance (double-layer capacitance, specific energy) of EDLCs that employ a mesoporous carbon model electrode with uniform, highly interconnected mesopores (3DOm carbon). Several ionic liquids with structurally diverse anions (tetrafluoroborate, trifluoromethanesulfonate, trifluoromethanesulfonimide) and cations (imidazolium, ammonium, pyridinium, piperidinium, and pyrrolidinium) were investigated. We show that the cation size has a significant effect on the electrolyte viscosity and conductivity, as well as the capacitance of EDLCs. Imidazolium- and pyridinium-based ionic liquids provide the highest cell capacitance, and ammonium-based ionic liquids offer potential windows much larger than imidazolium and pyridinium ionic liquids. Increasing the chain length of the alkyl substituents in 1-alkyl-3-methylimidazolium trifluoromethanesulfonimide does not widen the potential window of the ionic liquid. We identified the ionic liquids that maximize the specific energies of EDLCs through the combined effects of their potential windows and the double-layer capacitance. The highest specific energies are obtained with ionic liquid electrolytes that possess moderate electrochemical stability, small ionic volumes, low viscosity, and hence high conductivity, the best performing ionic liquid tested being 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide.

A Liquid Optical Phase Shifter with an Embedded Electrowetting Actuator

PubMed Central

Ashtiani, Alireza Ousati; Jiang, Hongrui

2017-01-01

We demonstrate an electrowetting-based liquid optical phase shifter. The phase shifter consists of two immiscible liquid layers with different refractive indices. Sandwiched between the two liquids is a rigid membrane that moves freely along the optical axis and supported by a compliant surround. When applied with a pressure, the thicknesses of both liquid layers change, which induces a difference in optical path, resulting in a phase shift. A miniaturized electrowetting-based actuator is used to produce hydraulic pressure. A multi-layered SU8 bonded structure was fabricated. A phase shift of 171° was observed when the device was incorporated in a Mach-Zehnder interferometer and driven with 100 V. PMID:29038640

Surface modification of active material structures in battery electrodes

DOEpatents

Erickson, Michael; Tikhonov, Konstantin

2016-02-02

Provided herein are methods of processing electrode active material structures for use in electrochemical cells or, more specifically, methods of forming surface layers on these structures. The structures are combined with a liquid to form a mixture. The mixture includes a surface reagent that chemically reacts and forms a surface layer covalently bound to the structures. The surface reagent may be a part of the initial liquid or added to the mixture after the liquid is combined with the structures. In some embodiments, the mixture may be processed to form a powder containing the structures with the surface layer thereon. Alternatively, the mixture may be deposited onto a current collecting substrate and dried to form an electrode layer. Furthermore, the liquid may be an electrolyte containing the surface reagent and a salt. The liquid soaks the previously arranged electrodes in order to contact the structures with the surface reagent.

Triangular Black Phosphorus Atomic Layers by Liquid Exfoliation.

PubMed

Seo, Soonjoo; Lee, Hyun Uk; Lee, Soon Chang; Kim, Yooseok; Kim, Hyeran; Bang, Junhyeok; Won, Jonghan; Kim, Youngjun; Park, Byoungnam; Lee, Jouhahn

2016-03-30

Few-layer black phosphorus (BP) is the most promising material among the two-dimensional materials due to its layered structure and the excellent semiconductor properties. Currently, thin BP atomic layers are obtained mostly by mechanical exfoliation of bulk BP, which limits applications in thin-film based electronics due to a scaling process. Here we report highly crystalline few-layer black phosphorus thin films produced by liquid exfoliation. We demonstrate that the liquid-exfoliated BP forms a triangular crystalline structure on SiO2/Si (001) and amorphous carbon. The highly crystalline BP layers are faceted with a preferred orientation of the (010) plane on the sharp edge, which is an energetically most favorable facet according to the density functional theory calculations. Our results can be useful in understanding the triangular BP structure for large-area applications in electronic devices using two-dimensional materials. The sensitivity and selectivity of liquid-exfoliated BP to gas vapor demonstrate great potential for practical applications as sensors.

Triangular Black Phosphorus Atomic Layers by Liquid Exfoliation

PubMed Central

Seo, Soonjoo; Lee, Hyun Uk; Lee, Soon Chang; Kim, Yooseok; Kim, Hyeran; Bang, Junhyeok; Won, Jonghan; Kim, Youngjun; Park, Byoungnam; Lee, Jouhahn

2016-01-01

Few-layer black phosphorus (BP) is the most promising material among the two-dimensional materials due to its layered structure and the excellent semiconductor properties. Currently, thin BP atomic layers are obtained mostly by mechanical exfoliation of bulk BP, which limits applications in thin-film based electronics due to a scaling process. Here we report highly crystalline few-layer black phosphorus thin films produced by liquid exfoliation. We demonstrate that the liquid-exfoliated BP forms a triangular crystalline structure on SiO2/Si (001) and amorphous carbon. The highly crystalline BP layers are faceted with a preferred orientation of the (010) plane on the sharp edge, which is an energetically most favorable facet according to the density functional theory calculations. Our results can be useful in understanding the triangular BP structure for large-area applications in electronic devices using two-dimensional materials. The sensitivity and selectivity of liquid-exfoliated BP to gas vapor demonstrate great potential for practical applications as sensors. PMID:27026070

Perceptual transparency from image deformation.

PubMed

Kawabe, Takahiro; Maruya, Kazushi; Nishida, Shin'ya

2015-08-18

Human vision has a remarkable ability to perceive two layers at the same retinal locations, a transparent layer in front of a background surface. Critical image cues to perceptual transparency, studied extensively in the past, are changes in luminance or color that could be caused by light absorptions and reflections by the front layer, but such image changes may not be clearly visible when the front layer consists of a pure transparent material such as water. Our daily experiences with transparent materials of this kind suggest that an alternative potential cue of visual transparency is image deformations of a background pattern caused by light refraction. Although previous studies have indicated that these image deformations, at least static ones, play little role in perceptual transparency, here we show that dynamic image deformations of the background pattern, which could be produced by light refraction on a moving liquid's surface, can produce a vivid impression of a transparent liquid layer without the aid of any other visual cues as to the presence of a transparent layer. Furthermore, a transparent liquid layer perceptually emerges even from a randomly generated dynamic image deformation as long as it is similar to real liquid deformations in its spatiotemporal frequency profile. Our findings indicate that the brain can perceptually infer the presence of "invisible" transparent liquids by analyzing the spatiotemporal structure of dynamic image deformation, for which it uses a relatively simple computation that does not require high-level knowledge about the detailed physics of liquid deformation.

Numerical Simulation of Convective Heat and Mass Transfer in a Two-Layer System

NASA Astrophysics Data System (ADS)

Myznikova, B. I.; Kazaryan, V. A.; Tarunin, E. L.; Wertgeim, I. I.

The results are presented of mathematical and computer modeling of natural convection in the “liquid-gas” two-layer system, filling a vertical cylinder surrounded by solid heat conductive tract. The model describes approximately the conjugate heat and mass transfer in the underground oil product storage, filled partially by a hydrocarbon liquid, with natural gas layer above the liquid surface. The geothermal gradient in a rock mass gives rise to the intensive convection in the liquid-gas system. The consideration is worked out for laminar flows, laminar-turbulent transitional regimes, and developed turbulent flows.

Stretchable Metamaterial Absorber Using Liquid Metal-Filled Polydimethylsiloxane (PDMS)

PubMed Central

Kim, Kyeongseob; Lee, Dongju; Eom, Seunghyun; Lim, Sungjoon

2016-01-01

A stretchable metamaterial absorber is proposed in this study. The stretchability was achieved by liquid metal and polydimethylsiloxane (PDMS). To inject liquid metal, microfluidic channels were fabricated using PDMS powers and microfluidic-channel frames, which were built using a three-dimensional printer. A top conductive pattern and ground plane were designed after considering the easy injection of liquid metal. The proposed metamaterial absorber comprises three layers of PDMS substrate. The top layer is for the top conductive pattern, and the bottom layer is for the meandered ground plane. Flat PDMS layers were inserted between the top and bottom PDMS layers. The measured absorptivity of the fabricated absorber was 97.8% at 18.5 GHz, and the absorption frequency increased from 18.5 to 18.65 GHz as the absorber was stretched from its original length (5.2 cm) to 6.4 cm. PMID:27077861

Air plasma treatment of liquid covered tissue: long timescale chemistry

NASA Astrophysics Data System (ADS)

Lietz, Amanda M.; Kushner, Mark J.

2016-10-01

Atmospheric pressure plasmas have shown great promise for the treatment of wounds and cancerous tumors. In these applications, the sample is usually covered by a thin layer of a biological liquid. The reactive oxygen and nitrogen species (RONS) generated by the plasma activate and are processed by the liquid before the plasma produced activation reaches the tissue. The synergy between the plasma and the liquid, including evaporation and the solvation of ions and neutrals, is critical to understanding the outcome of plasma treatment. The atmospheric pressure plasma sources used in these procedures are typically repetitively pulsed. The processes activated by the plasma sources have multiple timescales—from a few ns during the discharge pulse to many minutes for reactions in the liquid. In this paper we discuss results from a computational investigation of plasma-liquid interactions and liquid phase chemistry using a global model with the goal of addressing this large dynamic range in timescales. In modeling air plasmas produced by a dielectric barrier discharge over liquid covered tissue, 5000 voltage pulses were simulated, followed by 5 min of afterglow. Due to the accumulation of long-lived species such as ozone and N x O y , the gas phase dynamics of the 5000th discharge pulse are different from those of the first pulse, particularly with regards to the negative ions. The consequences of applied voltage, gas flow, pulse repetition frequency, and the presence of organic molecules in the liquid on the gas and liquid reactive species are discussed.

Structure, Hydrodynamics, and Phase Transition of Freely Suspended Liquid Crystals

NASA Technical Reports Server (NTRS)

Clark, Noel A.

2000-01-01

Smectic liquid crystals are phases of rod shaped molecules organized into one dimensionally (1D) periodic arrays of layers, each layer being between one and two molecular lengths thick. In the least ordered smectic phases, the smectics A and C, each layer is a two dimensional (2D) liquid. Additionally there are a variety of more ordered smectic phases having hexatic short range translational order or 2D crystalline quasi long range translational order within the layers. The inherent fluid-layer structure and low vapor pressure of smectic liquid crystals enable the long term stabilization of freely suspended, single component, layered fluid films as thin as 30A, a single molecular layer. The layering forces the films to be an integral number of smectic layers thick, quantizing their thickness in layer units and forcing a film of a particular number of layers to be physically homogeneous with respect to its layer structure over its entire area. Optical reflectivity enables the precise determination of the number of layers. These ultrathin freely suspended liquid crystal films are structures of fundamental interest in condensed matter and fluid physics. They are the thinnest known stable condensed phase fluid structures and have the largest surface-to-volume ratio of any stable fluid preparation, making them ideal for the study of the effects of reduced dimensionality on phase behavior and on fluctuation and interface phenomena. Their low vapor pressure and quantized thickness enable the effective use of microgravity to extend the study of basic capillary phenomena to ultrathin fluid films. Freely suspended films have been a wellspring of new liquid crystal physics. They have been used to provide unique experimental conditions for the study of condensed phase transitions in two dimensions. They are the only system in which the hexatic has been unambiguously identified as a phase of matter, and the only physical system in which fluctuations of a 2D XY system and Kosterlitz Thouless phase transition has been observed and 2D XY quasi long range order verified. Smectic films have enabled the precise determination of smectic layer electron density and positional fluctuation profile and have been used to show that the interlayer interactions in anti-ferroelectric tilted smectics do not extend significantly beyond nearest neighbors. The interactions which are operative in liquid crystals are generally weak in comparison to those in crystalline phases, leading to the facile manipulation of the order in liquid crystals by external agents such as applied fields and surfaces. Effects arising from weak ordering are significantly enhanced in ultrathin free films and filaments wherein the intermolecular coupling is effectively reduced by loss of neighbors. Over the past four years this research, which we now detail, has produced a host of exciting new discoveries and unexpected results, maintaining the position of the study of freely suspended liquid crystal structures as one of most exciting and fruitful areas of complex fluid physics. In addition, several potentially interesting microgravity free film experiments have been identified.

Bio-inspired direct patterning functional nanothin microlines: controllable liquid transfer.

PubMed

Wang, Qianbin; Meng, Qingan; Wang, Pengwei; Liu, Huan; Jiang, Lei

2015-04-28

Developing a general and low-cost strategy that enables direct patterning of microlines with nanometer thickness from versatile liquid-phase functional materials and precise positioning of them on various substrates remains a challenge. Herein, with inspiration from the oriental wisdom to control ink transfer by Chinese brushes, we developed a facile and general writing strategy to directly pattern various functional microlines with homogeneous distribution and nanometer-scale thickness. It is demonstrated that the width and thickness of the microlines could be well-controlled by tuning the writing method, providing guidance for the adaptation of this technique to various systems. It is also shown that various functional liquid-phase materials, such as quantum dots, small molecules, polymers, and suspensions of nanoparticles, could directly write on the substrates with intrinsic physicochemical properties well-preserved. Moreover, this technique enabled direct patterning of liquid-phase materials on certain microdomains, even in multiple layered style, thus a microdomain localized chemical reaction and the patterned surface chemical modification were enabled. This bio-inspired direct writing device will shed light on the template-free printing of various functional micropatterns, as well as the integrated functional microdevices.

Temperature Stratification in a Cryogenic Fuel Tank

NASA Technical Reports Server (NTRS)

Daigle, Matthew John; Smelyanskiy, Vadim; Boschee, Jacob; Foygel, Michael Gregory

2013-01-01

A reduced dynamical model describing temperature stratification effects driven by natural convection in a liquid hydrogen cryogenic fuel tank has been developed. It accounts for cryogenic propellant loading, storage, and unloading in the conditions of normal, increased, and micro- gravity. The model involves multiple horizontal control volumes in both liquid and ullage spaces. Temperature and velocity boundary layers at the tank walls are taken into account by using correlation relations. Heat exchange involving the tank wall is considered by means of the lumped-parameter method. By employing basic conservation laws, the model takes into consideration the major multi-phase mass and energy exchange processes involved, such as condensation-evaporation of the hydrogen, as well as flows of hydrogen liquid and vapor in the presence of pressurizing helium gas. The model involves a liquid hydrogen feed line and a tank ullage vent valve for pressure control. The temperature stratification effects are investigated, including in the presence of vent valve oscillations. A simulation of temperature stratification effects in a generic cryogenic tank has been implemented in Matlab and results are presented for various tank conditions.

Sintered Lining for Heat-Pipe Evaporator

NASA Technical Reports Server (NTRS)

Ernst, D. M.; Eastman, G. Y.

1985-01-01

Hotspots eliminated by lining inner wall. Distribution of heat transfer liquid in heat-pipe evaporator improved by lining inner wall with layer of sintered metal. Sintered layer takes place of layer of screen wick formerly sintered or bonded to wall. Since sintered layer always full of liquid, no hotspot of type that previously arose where former screen wick did not fit properly against wall.

Breakthrough to Non-Vacuum Deposition of Single-Crystal, Ultra-Thin, Homogeneous Nanoparticle Layers: A Better Alternative to Chemical Bath Deposition and Atomic Layer Deposition

PubMed Central

Liao, Yu-Kuang; Liu, Yung-Tsung; Hsieh, Dan-Hua; Shen, Tien-Lin; Hsieh, Ming-Yang; Tzou, An-Jye; Chen, Shih-Chen; Tsai, Yu-Lin; Lin, Wei-Sheng; Chan, Sheng-Wen; Shen, Yen-Ping; Cheng, Shun-Jen; Chen, Chyong-Hua; Wu, Kaung-Hsiung; Chen, Hao-Ming; Kuo, Shou-Yi; Charlton, Martin D. B.; Hsieh, Tung-Po; Kuo, Hao-Chung

2017-01-01

Most thin-film techniques require a multiple vacuum process, and cannot produce high-coverage continuous thin films with the thickness of a few nanometers on rough surfaces. We present a new ”paradigm shift” non-vacuum process to deposit high-quality, ultra-thin, single-crystal layers of coalesced sulfide nanoparticles (NPs) with controllable thickness down to a few nanometers, based on thermal decomposition. This provides high-coverage, homogeneous thickness, and large-area deposition over a rough surface, with little material loss or liquid chemical waste, and deposition rates of 10 nm/min. This technique can potentially replace conventional thin-film deposition methods, such as atomic layer deposition (ALD) and chemical bath deposition (CBD) as used by the Cu(In,Ga)Se2 (CIGS) thin-film solar cell industry for decades. We demonstrate 32% improvement of CIGS thin-film solar cell efficiency in comparison to reference devices prepared by conventional CBD deposition method by depositing the ZnS NPs buffer layer using the new process. The new ZnS NPs layer allows reduction of an intrinsic ZnO layer, which can lead to severe shunt leakage in case of a CBD buffer layer. This leads to a 65% relative efficiency increase. PMID:28383488

Effect of film thickness on morphological evolution in dewetting and crystallization of polystyrene/poly(ε-caprolactone) blend films.

PubMed

Ma, Meng; He, Zhoukun; Yang, Jinghui; Chen, Feng; Wang, Ke; Zhang, Qin; Deng, Hua; Fu, Qiang

2011-11-01

In this Article, the morphological evolution in the blend thin film of polystyrene (PS)/poly(ε-caprolactone) (PCL) was investigated via mainly AFM. It was found that an enriched two-layer structure with PS at the upper layer and PCL at the bottom layer was formed during spinning coating. By changing the solution concentration, different kinds of crystal morphologies, such as finger-like, dendritic, and spherulitic-like, could be obtained at the bottom PCL layer. These different initial states led to the morphological evolution processes to be quite different from each other, so the phase separation, dewetting, and crystalline morphology of PS/PCL blend films as a function of time were studied. It was interesting to find that the morphological evolution of PS at the upper layer was largely dependent on the film thickness. For the ultrathin (15 nm) blend film, a liquid-solid/liquid-liquid dewetting-wetting process was observed, forming ribbons that rupture into discrete circular PS islands on voronoi finger-like PCL crystal. For the thick (30 nm) blend film, the liquid-liquid dewetting of the upper PS layer from the underlying adsorbed PCL layer was found, forming interconnected rim structures that rupture into discrete circular PS islands embedded in the single lamellar PCL dendritic crystal due to Rayleigh instability. For the thicker (60 nm) blend film, a two-step liquid-liquid dewetting process with regular holes decorated with dendritic PCL crystal at early annealing stage and small holes decorated with spherulite-like PCL crystal among the early dewetting holes at later annealing stage was observed. The mechanism of this unusual morphological evolution process was discussed on the basis of the entropy effect and annealing-induced phase separation.

A polarization-independent liquid crystal phase modulation using polymer-network liquid crystals in a 90° twisted cell

NASA Astrophysics Data System (ADS)

Lin, Yi-Hsin; Chen, Ming-Syuan; Lin, Wei-Chih; Tsou, Yu-Shih

2012-07-01

A polarization-independent liquid crystal phase modulation using polymer-network liquid crystals in a 90° twisted cell (T-PNLC) is demonstrated. T-PNLC consists of three layers. Liquid crystal (LC) directors in the two layers near glass substrates are orthogonal to each other and those two layers modulate two eigen-polarizations of an incident light. As a result, two eigen-polarizations of an incident light experience the same phase shift. In the middle layer, LC directors are perpendicular to the glass substrate and contribute no phase shift. The phase shift of T-PNLC is electrically tunable and polarization-independent. T-PNLC does not require any bias voltage for operation. The phase shift is 0.28 π rad for the voltage of 30 Vrms. By measuring and analyzing the optical phase shift of T-PNLC at the oblique incidence of transverse magnetic wave, the pretilt angle of LC directors and the effective thickness of three layers are obtained and discussed. The potential applications are spatial light modulators, laser beam steering, and micro-lens arrays.

Coupled Land Surface-Subsurface Hydrogeophysical Inverse Modeling to Estimate Soil Organic Carbon Content in an Arctic Tundra

NASA Astrophysics Data System (ADS)

Tran, A. P.; Dafflon, B.; Hubbard, S.

2017-12-01

Soil organic carbon (SOC) is crucial for predicting carbon climate feedbacks in the vulnerable organic-rich Arctic region. However, it is challenging to achieve this property due to the general limitations of conventional core sampling and analysis methods. In this study, we develop an inversion scheme that uses single or multiple datasets, including soil liquid water content, temperature and ERT data, to estimate the vertical profile of SOC content. Our approach relies on the fact that SOC content strongly influences soil hydrological-thermal parameters, and therefore, indirectly controls the spatiotemporal dynamics of soil liquid water content, temperature and their correlated electrical resistivity. The scheme includes several advantages. First, this is the first time SOC content is estimated by using a coupled hydrogeophysical inversion. Second, by using the Community Land Model, we can account for the land surface dynamics (evapotranspiration, snow accumulation and melting) and ice/liquid phase transition. Third, we combine a deterministic and an adaptive Markov chain Monte Carlo optimization algorithm to better estimate the posterior distributions of desired model parameters. Finally, the simulated subsurface variables are explicitly linked to soil electrical resistivity via petrophysical and geophysical models. We validate the developed scheme using synthetic experiments. The results show that compared to inversion of single dataset, joint inversion of these datasets significantly reduces parameter uncertainty. The joint inversion approach is able to estimate SOC content within the shallow active layer with high reliability. Next, we apply the scheme to estimate OC content along an intensive ERT transect in Barrow, Alaska using multiple datasets acquired in the 2013-2015 period. The preliminary results show a good agreement between modeled and measured soil temperature, thaw layer thickness and electrical resistivity. The accuracy of estimated SOC content will be evaluated by comparison with measurements from soil samples along the transect. Our study presents a new surface-subsurface, deterministic-stochastic hydrogeophysical inversion approach, as well as the benefit of including multiple types of data to estimate SOC and associated hydrological-thermal dynamics.

Ion-beam-spurted dimethyl-sulfate-doped PEDOT:PSS composite-layer-aligning liquid crystal with low residual direct-current voltage

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Yang; Lee, Ju Hwan; Seo, Dae-Shik, E-mail: dsseo@yonsei.ac.kr

2016-09-05

Thin ion-beam (IB)-spurted dimethyl sulfate/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (DMS/PEDOT:PSS) layers with improved electro-optic performance are presented for aligning liquid crystals. IB spurting is effective for enhancing the conductivity of such layers, as well as the anchoring energy of the liquid crystals sandwiched between them. Compared with a commercial twisted-nematic cell assembled with polyimide alignment layers, the same cell assembled with 3.0-keV IB-spurted DMS/PEDOT:PSS alignment layers shows a 38% faster switching and a 93% lower residual direct current. The improved electro-optic performance here is likely due to the enhanced electric field effect and the charge-releasing ability of thin IB-spurted DMS/PEDOT:PSS layers.

Modeling liquid organic thin films on substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bernacki, Bruce E.; Johnson, Timothy J.; Myers, Tanya L.

We present the rationale, methods, and results of modeling of thin film organic liquids on various substrates. These liquids may coat surfaces (substrates) either as a result of their production, dispersal via aerosols or spills. Identification of unknown coated surfaces using either reflectance or emittance spectroscopy cannot be accomplished simply through reference to reflectance signature libraries since neither the thickness of the liquid layer nor the substrate type is known beforehand and both contribute to the signature. Liquid spectral libraries offer the complex index of refraction (n,k) as a function of wavelength which by itself is useful only for thickmore » (bulk) liquid layers via computation of reflectance and transmittance coefficients using the Fresnel equations. Thin liquid layers both reflect and refract incident light in combination with reflectance from the substrate. We show modeling of various organic liquids on substrates using commercial thin film design and modeling software, as well as Monte Carlo ray tracing software to demonstrate the variety of potential signatures encountered that depend on the thickness of the liquid layer as well as the characteristics of the substrate (metal or dielectric). These substrates give rise to transflectance behavior, while many dielectric substrates have rich absorption features that provide complex signatures that combine attributes of both the liquid and the substrate. Knowledge of the complex index of refraction of both target liquids and substrates is essential in order to synthesize spectra necessary in the application of target identification algorithms.« less

Sheath liquid interface for the coupling of normal-phase liquid chromatography with electrospray mass spectrometry and its application to the analysis of neoflavonoids.

PubMed

Charles, Laurence; Laure, Frédéric; Raharivelomanana, Phila; Bianchini, Jean-Pierre

2005-01-01

A novel interface that allows normal-phase liquid chromatography to be coupled with electrospray ionization (ESI) is reported. A make-up solution of 60 mM ammonium acetate in methanol, infused at a 5 microl min(-1) flow-rate at the tip of the electrospray probe, provides a sheath liquid which is poorly miscible with the chromatographic effluent, but promotes efficient ionization of the targeted analytes. Protonated molecules generated in the ESI source were subjected to tandem mass spectrometric experiments in a triple-quadrupole mass spectrometer. The main fragmentation reactions were characterized for each analyte and specific mass spectral transitions were used to acquire chromatographic data in the multiple reaction monitoring detection mode. Results obtained during optimization of the sheath liquid composition and flow-rate suggest that the electrospray process was mainly under the control of the make-up solution, and that it forms an external charged layer around a neutral chromatographic mobile phase core. This sheath liquid interface was implemented for the analysis of some neoflavonoid compounds and its performance was evaluated. Limits of detection were established for calophillolide, inophyllum B, inophyllum P and inophyllum C at 100, 25, 15 and 100 ng ml(-1), respectively.

Depositing spacing layers on magnetic film with liquid phase epitaxy

NASA Technical Reports Server (NTRS)

Moody, J. W.; Shaw, R. W.; Sanfort, R. M.

1975-01-01

Liquid phase epitaxy spacing layer is compatible with systems which are hard-bubble proofed by use of second magnetic garnet film as capping layer. Composite is superior in that: circuit fabrication time is reduced; adherence is superior; visibility is better; and, good match of thermal expansion coefficients is provided.

Structural behavior and dynamics of an anomalous fluid between attractive and repulsive walls: Templating, molding, and superdiffusion

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leoni, Fabio; Franzese, Giancarlo

2014-11-07

Confinement can modify the dynamics, the thermodynamics, and the structural properties of liquid water, the prototypical anomalous liquid. By considering a generic model for anomalous liquids, suitable for describing solutions of globular proteins, colloids, or liquid metals, we study by molecular dynamics simulations the effect that an attractive wall with structure and a repulsive wall without structure have on the phases, the crystal nucleation, and the dynamics of the fluid. We find that at low temperatures the large density of the attractive wall induces a high-density, high-energy structure in the first layer (“templating” effect). In turn, the first layer inducesmore » a “molding” effect on the second layer determining a structure with reduced energy and density, closer to the average density of the system. This low-density, low-energy structure propagates further through the layers by templating effect and can involve all the existing layers at the lowest temperatures investigated. Therefore, although the high-density, high-energy structure does not self-reproduce further than the first layer, the structured wall can have a long-range influence thanks to a sequence of templating, molding, and templating effects through the layers. We find that the walls also have an influence on the dynamics of the liquid, with a stronger effect near the attractive wall. In particular, we observe that the dynamics is largely heterogeneous (i) among the layers, as a consequence of the sequence of structures caused by the walls presence, and (ii) within the same layer, due to superdiffusive liquid veins within a frozen matrix of particles near the walls at low temperature and high density. Hence, the partial freezing of the first layer does not correspond necessarily to an effective reduction of the channel's section in terms of transport properties, as suggested by other authors.« less

Structural behavior and dynamics of an anomalous fluid between attractive and repulsive walls: templating, molding, and superdiffusion.

PubMed

Leoni, Fabio; Franzese, Giancarlo

2014-11-07

Confinement can modify the dynamics, the thermodynamics, and the structural properties of liquid water, the prototypical anomalous liquid. By considering a generic model for anomalous liquids, suitable for describing solutions of globular proteins, colloids, or liquid metals, we study by molecular dynamics simulations the effect that an attractive wall with structure and a repulsive wall without structure have on the phases, the crystal nucleation, and the dynamics of the fluid. We find that at low temperatures the large density of the attractive wall induces a high-density, high-energy structure in the first layer ("templating" effect). In turn, the first layer induces a "molding" effect on the second layer determining a structure with reduced energy and density, closer to the average density of the system. This low-density, low-energy structure propagates further through the layers by templating effect and can involve all the existing layers at the lowest temperatures investigated. Therefore, although the high-density, high-energy structure does not self-reproduce further than the first layer, the structured wall can have a long-range influence thanks to a sequence of templating, molding, and templating effects through the layers. We find that the walls also have an influence on the dynamics of the liquid, with a stronger effect near the attractive wall. In particular, we observe that the dynamics is largely heterogeneous (i) among the layers, as a consequence of the sequence of structures caused by the walls presence, and (ii) within the same layer, due to superdiffusive liquid veins within a frozen matrix of particles near the walls at low temperature and high density. Hence, the partial freezing of the first layer does not correspond necessarily to an effective reduction of the channel's section in terms of transport properties, as suggested by other authors.

Fabrication Methods for Adaptive Deformable Mirrors

NASA Technical Reports Server (NTRS)

Toda, Risaku; White, Victor E.; Manohara, Harish; Patterson, Keith D.; Yamamoto, Namiko; Gdoutos, Eleftherios; Steeves, John B.; Daraio, Chiara; Pellegrino, Sergio

2013-01-01

Previously, it was difficult to fabricate deformable mirrors made by piezoelectric actuators. This is because numerous actuators need to be precisely assembled to control the surface shape of the mirror. Two approaches have been developed. Both approaches begin by depositing a stack of piezoelectric films and electrodes over a silicon wafer substrate. In the first approach, the silicon wafer is removed initially by plasmabased reactive ion etching (RIE), and non-plasma dry etching with xenon difluoride (XeF2). In the second approach, the actuator film stack is immersed in a liquid such as deionized water. The adhesion between the actuator film stack and the substrate is relatively weak. Simply by seeping liquid between the film and the substrate, the actuator film stack is gently released from the substrate. The deformable mirror contains multiple piezoelectric membrane layers as well as multiple electrode layers (some are patterned and some are unpatterned). At the piezolectric layer, polyvinylidene fluoride (PVDF), or its co-polymer, poly(vinylidene fluoride trifluoroethylene P(VDF-TrFE) is used. The surface of the mirror is coated with a reflective coating. The actuator film stack is fabricated on silicon, or silicon on insulator (SOI) substrate, by repeatedly spin-coating the PVDF or P(VDFTrFE) solution and patterned metal (electrode) deposition. In the first approach, the actuator film stack is prepared on SOI substrate. Then, the thick silicon (typically 500-micron thick and called handle silicon) of the SOI wafer is etched by a deep reactive ion etching process tool (SF6-based plasma etching). This deep RIE stops at the middle SiO2 layer. The middle SiO2 layer is etched by either HF-based wet etching or dry plasma etch. The thin silicon layer (generally called a device layer) of SOI is removed by XeF2 dry etch. This XeF2 etch is very gentle and extremely selective, so the released mirror membrane is not damaged. It is possible to replace SOI with silicon substrate, but this will require tighter DRIE process control as well as generally longer and less efficient XeF2 etch. In the second approach, the actuator film stack is first constructed on a silicon wafer. It helps to use a polyimide intermediate layer such as Kapton because the adhesion between the polyimide and silicon is generally weak. A mirror mount ring is attached by using adhesive. Then, the assembly is partially submerged in liquid water. The water tends to seep between the actuator film stack and silicon substrate. As a result, the actuator membrane can be gently released from the silicon substrate. The actuator membrane is very flat because it is fixed to the mirror mount prior to the release. Deformable mirrors require extremely good surface optical quality. In the technology described here, the deformable mirror is fabricated on pristine substrates such as prime-grade silicon wafers. The deformable mirror is released by selectively removing the substrate. Therefore, the released deformable mirror surface replicates the optical quality of the underlying pristine substrate.

Method and apparatus to produce and maintain a thick, flowing, liquid lithium first wall for toroidal magnetic confinement DT fusion reactors

DOEpatents

Woolley, Robert D.

2002-01-01

A system for forming a thick flowing liquid metal, in this case lithium, layer on the inside wall of a toroid containing the plasma of a deuterium-tritium fusion reactor. The presence of the liquid metal layer or first wall serves to prevent neutron damage to the walls of the toroid. A poloidal current in the liquid metal layer is oriented so that it flows in the same direction as the current in a series of external magnets used to confine the plasma. This current alignment results in the liquid metal being forced against the wall of the toroid. After the liquid metal exits the toroid it is pumped to a heat extraction and power conversion device prior to being reentering the toroid.

Charge Transport and Phase Behavior of Imidazolium-Based Ionic Liquid Crystals from Fully Atomistic Simulations.

PubMed

Quevillon, Michael J; Whitmer, Jonathan K

2018-01-02

Ionic liquid crystals occupy an intriguing middle ground between room-temperature ionic liquids and mesostructured liquid crystals. Here, we examine a non-polarizable, fully atomistic model of the 1-alkyl-3-methylimidazolium nitrate family using molecular dynamics in the constant pressure-constant temperature ensemble. These materials exhibit a distinct "smectic" liquid phase, characterized by layers formed by the molecules, which separate the ionic and aliphatic moieties. In particular, we discuss the implications this layering may have for electrolyte applications.

Relationships between Liquid Atomization and Solid Fragmentation

DTIC Science & Technology

2016-03-01

Sallam, C. Aalburg, G.M. Faeth, K.-C. Lin, C.D. Carter, and T.A. Jackson, Primary Breakup of Aerated- Liquid Jets in Supersonic Crossflows, Atomization...Wu, L.-K. Tseng, and G. M. Faeth, Primary Breakup in Gas / Liquid Mixing Layers for Turbulent Liquids , Atomization and Sprays, 295-317, 1992 P.-K...Wu, G. A. Ruff, and G. M. Faeth, Primary Breakup in Liquid - Gas Mixing Layers, Atomization and Sprays, 1, 421-440, 1991 P.-K. Wu and G. M. Faeth

Structure for monolithic optical circuits

NASA Technical Reports Server (NTRS)

Evanchuk, Vincent L. (Inventor)

1984-01-01

A method for making monolithic optical circuits, with related optical devices as required or desired, on a supporting surface (10) consists of coating the supporting surface with reflecting metal or cladding resin, spreading a layer of liquid radiation sensitive plastic (12) on the surface, exposing the liquid plastic with a mask (14) to cure it in a desired pattern of light conductors (16, 18, 20), washing away the unexposed liquid plastic, and coating the conductors thus formed with reflective metal or cladding resin. The index of refraction for the cladding (22) is selected to be lower than for the conductors so that light in the conductors will be reflected by the interface with the cladding. For multiple level conductors, as where one conductor must cross over another, the process may be repeated to fabricate a bridge with columns (24, 26) of conductors to the next level, and conductor (28) between the columns. For more efficient transfer of energy over the bridge, faces at 45.degree. may be formed to reflect light up and across the bridge.

Improvement of Aconitum napellus micropropagation by liquid culture on floating membrane rafts.

PubMed

Watad, A A; Kochba, M; Nissim, A; Gaba, V

1995-03-01

An efficient method was developed using floating membrane rafts (Liferaft(™)) for the micropropagation of Aconitum napellus (Ranunculaceae), a cut flower crop with a low natural propagation rate. This was achieved by introducing shoot tips into culture on Murashige and Skoog's (1962) solid medium, or liquid medium-supported rafts, supplemented by different levels of benzyl adenine (BA). Optimum shoot proliferation on solid medium required 4mg/l BA, whereas for expiants supported on rafts optimal proliferation was achieved at 0.25mg/l BA. Maximum shoot proliferation was found using the floating rafts (propagation ratio of 4.2 per month), 45% higher than the maximum value on solid medium. A similar value could be obtained on solid medium after a period of 2 months. The optimal response to BA was similar for fresh weight gain and shoot length. Growth in a shallow layer of liquid in shake flasks gives a similar shoot multiplication rate to that on floating rafts; however, submerged leaves brown and die.

Smectic layer instabilities in liquid crystals.

PubMed

Dierking, Ingo; Mitov, Michel; Osipov, Mikhail A

2015-02-07

Scientists aspire to understand the underlying physics behind the formation of instabilities in soft matter and how to manipulate them for diverse investigations, while engineers aim to design materials that inhibit or impede the nucleation and growth of these instabilities in critical applications. The present paper reviews the field-induced rotational instabilities which may occur in chiral smectic liquid-crystalline layers when subjected to an asymmetric electric field. Such instabilities destroy the so-named bookshelf geometry (in which the smectic layers are normal to the cell surfaces) and have a detrimental effect on all applications of ferroelectric liquid crystals as optical materials. The transformation of the bookshelf geometry into horizontal chevron structures (in which each layer is in a V-shaped structure), and the reorientation dynamics of these chevrons, are discussed in details with respect to the electric field conditions, the material properties and the boundary conditions. Particular attention is given to the polymer-stabilisation of smectic phases as a way to forbid the occurrence of instabilities and the decline of related electro-optical performances. It is also shown which benefit may be gained from layer instabilities to enhance the alignment of the liquid-crystalline geometry in practical devices, such as optical recording by ferroelectric liquid crystals. Finally, the theoretical background of layer instabilities is given and discussed in relation to the experimental data.

Lithium ion intercalation in thin crystals of hexagonal TaSe2 gated by a polymer electrolyte

NASA Astrophysics Data System (ADS)

Wu, Yueshen; Lian, Hailong; He, Jiaming; Liu, Jinyu; Wang, Shun; Xing, Hui; Mao, Zhiqiang; Liu, Ying

2018-01-01

Ionic liquid gating has been used to modify the properties of layered transition metal dichalcogenides (TMDCs), including two-dimensional (2D) crystals of TMDCs used extensively recently in the device work, which has led to observations of properties not seen in the bulk. The main effect comes from the electrostatic gating due to the strong electric field at the interface. In addition, ionic liquid gating also leads to ion intercalation when the ion size of the gate electrolyte is small compared to the interlayer spacing of TMDCs. However, the microscopic processes of ion intercalation have rarely been explored in layered TMDCs. Here, we employed a technique combining photolithography device fabrication and electrical transport measurements on the thin crystals of hexagonal TaSe2 using multiple channel devices gated by a polymer electrolyte LiClO4/Polyethylene oxide (PEO). The gate voltage and time dependent source-drain resistances of these thin crystals were used to obtain information on the intercalation process, the effect of ion intercalation, and the correlation between the ion occupation of allowed interstitial sites and the device characteristics. We found a gate voltage controlled modulation of the charge density waves and a scattering rate of charge carriers. Our work suggests that ion intercalation can be a useful tool for layered materials engineering and 2D crystal device design.

Transient phases during fast crystallization of organic thin films from solution

NASA Astrophysics Data System (ADS)

Wan, Jing; Li, Yang; Ulbrandt, Jeffrey G.; Smilgies, Detlef-M.; Hollin, Jonathan; Whalley, Adam C.; Headrick, Randall L.

2016-01-01

We report an in situ microbeam grazing incidence X-ray scattering study of 2,7-dioctyl[1]benzothieno[3,2-b][1]benzothiophene (C8-BTBT) organic semiconductor thin film deposition by hollow pen writing. Multiple transient phases are observed during the crystallization for substrate temperatures up to ≈93 °C. The layered smectic liquid-crystalline phase of C8-BTBT initially forms and preceedes inter-layer ordering, followed by a transient crystalline phase for temperature >60 °C, and ultimately the stable phase. Based on these results, we demonstrate a method to produce extremely large grain size and high carrier mobility during high-speed processing. For high writing speed (25 mm/s), mobility up to 3.0 cm2/V-s has been observed.

Active probing of cloud multiple scattering, optical depth, vertical thickness, and liquid water content using wide-angle imaging lidar

NASA Astrophysics Data System (ADS)

Love, Steven P.; Davis, Anthony B.; Rohde, Charles A.; Tellier, Larry; Ho, Cheng

2002-09-01

At most optical wavelengths, laser light in a cloud lidar experiment is not absorbed but merely scattered out of the beam, eventually escaping the cloud via multiple scattering. There is much information available in this light scattered far from the input beam, information ignored by traditional 'on-beam' lidar. Monitoring these off-beam returns in a fully space- and time-resolved manner is the essence of our unique instrument, Wide Angle Imaging Lidar (WAIL). In effect, WAIL produces wide-field (60-degree full-angle) 'movies' of the scattering process and records the cloud's radiative Green functions. A direct data product of WAIL is the distribution of photon path lengths resulting from multiple scattering in the cloud. Following insights from diffusion theory, we can use the measured Green functions to infer the physical thickness and optical depth of the cloud layer, and, from there, estimate the volume-averaged liquid water content. WAIL is notable in that it is applicable to optically thick clouds, a regime in which traditional lidar is reduced to ceilometry. Here we present recent WAIL data on various clouds and discuss the extension of WAIL to full diurnal monitoring by means of an ultra-narrow magneto-optic atomic line filter for daytime measurements.

Globular, Sponge-like to Layer-like Morphological Transition in 1-n-Alkyl-3-methylimidazolium Octylsulfate Ionic Liquid Homologous Series.

PubMed

Kapoor, Utkarsh; Shah, Jindal K

2018-01-11

Segregation of polar and nonpolar domains in ionic liquids for which either the cation or anion is responsible for inducing nonpolar domains is well understood. On the other hand, information regarding the nanoscale heterogeneities originating due to the presence of nonpolar content on both the ions is rudimentary at this point. The present contribution is aimed at addressing this question and focuses on a molecular dynamics simulation study to probe nanoscale structural and aggregation features of the 1-n-alkyl-3-methylimidazolium [C n mim] octylsulfate [C 8 SO 4 ] ionic liquid homologous series (n = 2, 4, 6, 8, 10, and 12). The objective of this work is to determine the effect of increasing alkyl chain length in the cation on nonpolar domain formation, especially when the alkyl chain lengths from both the ions participate in defining such domains. The results indicate that all the ionic liquids form nonpolar domains, morphology of which gradually changes from globular, sponge-like to layer-like structure with increase in the cationic alkyl chain length. The length of the nonpolar domains calculated from the total structure factor for [C 10 mim][C 8 SO 4 ] is considerably higher than that reported for other imidazolium-based ionic liquid containing smaller anions. The structure factor for [C 12 mim][C 8 SO 4 ] ionic liquid contains multiple intermediate peaks separating the charge alternation peak and pre-peak, which points to nonpolar domains of varying lengths, an observation that remains to be validated. Analysis of the heterogeneous order parameters and orientational correlation functions of the alkyl chains further suggests an increase in the spatial heterogeneity and long-range order along the homologous series. The origin of rich diversity of structures obtained by introducing nonpolar content on both the ions is discussed.

D 2 and D-T Liquid-Layer Target Shots at the National Ignition Facility

DOE PAGES

Walters, Curtis; Alger, Ethan; Bhandarkar, Suhas; ...

2018-01-19

Experiments at the National Ignition Facility (NIF) using targets containing a deuterium-tritium (D-T) fuel layer have, until recently, required that a high-quality layer of solid D-T (herein referred to as an ice layer) be formed in the capsule. The development of a process to line the inner surface of a target capsule with a foam layer of a thickness that is typical of ice layers has resulted in the ability to field targets with liquid layers wetting the foam. Successful fielding of liquid-layer targets on NIF required not only a foam-lined capsule but also changes to the capsule filling processmore » and the manner with which the inventory is maintained in the capsule. Additionally, changes to target heater power and the temperature drops across target components were required in order to achieve the desired range of shot temperatures. Finally, these changes and the target’s performance during four target shots on NIF are discussed.« less

D 2 and D-T Liquid-Layer Target Shots at the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walters, Curtis; Alger, Ethan; Bhandarkar, Suhas

Experiments at the National Ignition Facility (NIF) using targets containing a deuterium-tritium (D-T) fuel layer have, until recently, required that a high-quality layer of solid D-T (herein referred to as an ice layer) be formed in the capsule. The development of a process to line the inner surface of a target capsule with a foam layer of a thickness that is typical of ice layers has resulted in the ability to field targets with liquid layers wetting the foam. Successful fielding of liquid-layer targets on NIF required not only a foam-lined capsule but also changes to the capsule filling processmore » and the manner with which the inventory is maintained in the capsule. Additionally, changes to target heater power and the temperature drops across target components were required in order to achieve the desired range of shot temperatures. Finally, these changes and the target’s performance during four target shots on NIF are discussed.« less

A thin-layer liquid culture technique for the growth of Helicobacter pylori.

PubMed

Joo, Jung-Soo; Park, Kyung-Chul; Song, Jae-Young; Kim, Dong-Hyun; Lee, Kyung-Ja; Kwon, Young-Cheol; Kim, Jung-Min; Kim, Kyung-Mi; Youn, Hee-Shang; Kang, Hyung-Lyun; Baik, Seung-Chul; Lee, Woo-Kon; Cho, Myung-Je; Rhee, Kwang-Ho

2010-08-01

Several attempts have been successful in liquid cultivation of Helicobaccter pylori. However, there is a need to improve the growth of H. pylori in liquid media in order to get affluent growth and a simple approach for examining bacterial properties. We introduce here a thin-layer liquid culture technique for the growth of H. pylori. A thin-layer liquid culture system was established by adding liquid media to a 90-mm diameter Petri dish. Optimal conditions for bacterial growth were investigated and then viability, growth curve, and released proteins were examined. Maximal growth of H. pylori was obtained by adding 3 mL of brucella broth supplemented with 10% horse to a Petri dish. H. pylori grew in both DMEM and RPMI-1640 supplemented with 10% fetal bovine serum and 0.5% yeast extract. Serum-free RPMI-1640 supported the growth of H. pylori when supplemented with dimethyl-beta-cyclodextrin (200 microg/mL) and 1% yeast extract. Under optimal growth, H. pylori grew exponentially for 28 hours, reaching a density of 3.4 OD(600) with a generation time of 3.3 hours. After 24 hours, cultures at a cell density of 1.0 OD(600) contained 1.3 +/- 0.1 x 10(9 )CFU/mL. gamma-Glutamyl transpeptidase, nuclease, superoxide dismutase, and urease were not detected in culture supernatants at 24 hours in thin-layer liquid culture, but were present at 48 hours, whereas alcohol dehydrogenase, alkylhydroperoxide reductase, catalase, and vacuolating cytotoxin were detected at 24 hours. Thin-layer liquid culture technique is feasible, and can serve as a versatile liquid culture technique for investigating bacterial properties of H. pylori.

Slippery liquid-infused porous surfaces having improved stability

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aizenberg, Joanna; Vogel, Nicolas

Methods and articles disclosed herein relate to liquid repellant surfaces having selective wetting and transport properties. An article having a repellant surface includes a substrate comprising surface features with re-entrant curvature and an immobilized layer of lubricating liquid wetting over the surface features. The surface features with re-entrant curvature can be designed to provide high repellency even after failure or removal of the immobilized layer of lubricating liquid under certain operating conditions.

Evaluation of the Effect of Exhausts from Liquid and Solid Rockets on Ozone Layer

NASA Astrophysics Data System (ADS)

Yamagiwa, Yoshiki; Ishimaki, Tetsuya

This paper reports the analytical results of the influences of solid rocket and liquid rocket exhausts on ozone layer. It is worried about that the exhausts from solid propellant rockets cause the ozone depletion in the ozone layer. Some researchers try to develop the analytical model of ozone depletion by rocket exhausts to understand its physical phenomena and to find the effective design of rocket to minimize its effect. However, these models do not include the exhausts from liquid rocket although there are many cases to use solid rocket boosters with a liquid rocket at the same time in practical situations. We constructed combined analytical model include the solid rocket exhausts and liquid rocket exhausts to analyze their effects. From the analytical results, we find that the exhausts from liquid rocket suppress the ozone depletion by solid rocket exhausts.

Impedance method for measuring shear elasticity of liquids

NASA Astrophysics Data System (ADS)

Badmaev, B. B.; Dembelova, T. S.; Damdinov, B. B.; Gulgenov, Ch. Zh.

2017-11-01

Experimental results of studying low-frequency (74 kHz) shear elasticity of polymer liquids by the impedance method (analogous to the Mason method) are presented. A free-volume thick liquid layer is placed on the horizontal surface of a piezoelectric quartz crystal with dimensions 34.7 × 12 × 5.5 cm. The latter performs tangential vibrations at resonance frequency. The liquid layer experiences shear strain, and shear waves should propagate in it. From the theory of the method, it follows that, with an increase in the layer thickness, both real and imaginary resonance frequency shifts should exhibit damped oscillations and tend to limiting values. For the liquids under study, the imaginary frequency shift far exceeds the real one, which testifies to the presence of bulk shear elasticity.

Thermal Transport at Solid-Liquid Interfaces: High Pressure Facilitates Heat Flow through Nonlocal Liquid Structuring.

PubMed

Han, Haoxue; Mérabia, Samy; Müller-Plathe, Florian

2017-05-04

The integration of three-dimensional microelectronics is hampered by overheating issues inherent to state-of-the-art integrated circuits. Fundamental understanding of heat transfer across soft-solid interfaces is important for developing efficient heat dissipation capabilities. At the microscopic scale, the formation of a dense liquid layer at the solid-liquid interface decreases the interfacial heat resistance. We show through molecular dynamics simulations of n-perfluorohexane on a generic wettable surface that enhancement of the liquid structure beyond a single adsorbed layer drastically enhances interfacial heat conductance. Pressure is used to control the extent of the liquid layer structure. The interfacial thermal conductance increases with pressure values up to 16.2 MPa at room temperature. Furthermore, it is shown that liquid structuring enhances the heat-transfer rate of high-energy lattice waves by broadening the transmission peaks in the heat flux spectrum. Our results show that pressure is an important external parameter that may be used to control interfacial heat conductance at solid-soft interfaces.

Charge Transport and Phase Behavior of Imidazolium-Based Ionic Liquid Crystals from Fully Atomistic Simulations

PubMed Central

2018-01-01

Ionic liquid crystals occupy an intriguing middle ground between room-temperature ionic liquids and mesostructured liquid crystals. Here, we examine a non-polarizable, fully atomistic model of the 1-alkyl-3-methylimidazolium nitrate family using molecular dynamics in the constant pressure–constant temperature ensemble. These materials exhibit a distinct “smectic” liquid phase, characterized by layers formed by the molecules, which separate the ionic and aliphatic moieties. In particular, we discuss the implications this layering may have for electrolyte applications. PMID:29301305

Influence of Cooling Condition on the Performance of Grinding Hardened Layer in Grind-hardening

NASA Astrophysics Data System (ADS)

Wang, G. C.; Chen, J.; Xu, G. Y.; Li, X.

2018-02-01

45# steel was grinded and hardened on a surface grinding machine to study the effect of three different cooling media, including emulsion, dry air and liquid nitrogen, on the microstructure and properties of the hardened layer. The results show that the microstructure of material surface hardened with emulsion is pearlite and no hardened layer. The surface roughness is small and the residual stress is compressive stress. With cooling condition of liquid nitrogen and dry air, the specimen surface are hardened, the organization is martensite, the surface roughness is also not changed, but high hardness of hardened layer and surface compressive stress were obtained when grinding using liquid nitrogen. The deeper hardened layer grinded with dry air was obtained and surface residual stress is tensile stress. This study provides an experimental basis for choosing the appropriate cooling mode to effectively control the performance of grinding hardened layer.

Monitoring of Soft Deposition Layers in Liquid-Filled Tubes with Guided Acoustic Waves Excited by Clamp-on Transducers.

PubMed

Tietze, Sabrina; Singer, Ferdinand; Lasota, Sandra; Ebert, Sandra; Landskron, Johannes; Schwuchow, Katrin; Drese, Klaus Stefan; Lindner, Gerhard

2018-02-09

The monitoring of liquid-filled tubes with respect to the formation of soft deposition layers such as biofilms on the inner walls calls for non-invasive and long-term stable sensors, which can be attached to existing pipe structures. For this task a method is developed, which uses an ultrasonic clamp-on device. This method is based on the impact of such deposition layers on the propagation of circumferential guided waves on the pipe wall. Such waves are partly converted into longitudinal compressional waves in the liquid, which are back-converted to guided waves in a circular cross section of the pipe. Validating this approach, laboratory experiments with gelatin deposition layers on steel tubes exhibited a distinguishable sensitivity of both wave branches with respect to the thickness of such layers. This allows the monitoring of the layer growth.

Shear-induced surface alignment of polymer dispersed liquid crystal microdroplets on the boundary layer

NASA Technical Reports Server (NTRS)

Parmar, D. S.; Singh, J. J.

1993-01-01

Polymer dispersed liquid crystal thin films have been deposited on a glass substrate, utilizing the processes of polymerization and solvent evaporation induced phase separation. Liquid crystal microdroplets trapped on the upper surface of the thin film respond to the shear stress due to air or gas flow on the surface layer. Response to an applied step shear stress input on the surface layer has been measured by measuring the time response of the transmitted light intensity. Initial results on the measurements of the light transmission as a function of the air flow differential pressure indicate that these systems offer features suitable for boundary layer and gas flow sensors.

The competition between the liquid-liquid dewetting and the liquid-solid dewetting.

PubMed

Xu, Lin; Shi, Tongfei; An, Lijia

2009-05-14

We investigate the dewetting behavior of the bilayer of air/PS/PMMA/silanized Si wafer and find the two competing dewetting pathways in the dewetting process. The upper layer dewets on the lower layer (dewetting pathway 1, the liquid-liquid dewetting) and the two layers rupture on the solid substrate (dewetting pathway 2, the liquid-solid dewetting). To the two competing dewetting pathways, the process of forming holes and the process of hole growth, influence their competing relation. In the process of forming holes, the time of forming holes is a main factor that influences their competing relation. During the process of hole growth, the dewetting velocity is a main factor that influences their competing relation. The liquid-liquid interfacial tension, the film thickness of the polymer, and the viscosity of the polymer are important factors that influence the time of forming holes and the dewetting velocity. When the liquid-liquid dewetting pathway and the liquid-solid dewetting pathway compete in the dewetting process, the competing relation can be controlled by changing the molecular weight of the polymer, the film thickness, and the annealing temperature. In addition, it is also found that the rim growth on the solid substrate is by a rolling mechanism in the process of hole growth.

Layered interfaces between immiscible liquids studied by density-functional theory and molecular-dynamics simulations.

PubMed

Geysermans, P; Elyeznasni, N; Russier, V

2005-11-22

We present a study of the structure in the interface between two immiscible liquids by density-functional theory and molecular-dynamics calculations. The liquids are modeled by Lennard-Jones potentials, which achieve immiscibility by suppressing the attractive interaction between unlike particles. The density profiles of the liquids display oscillations only in a limited part of the simple liquid-phase diagram (rho,T). When approaching the liquid-vapor coexistence, a significant depletion appears while the layering behavior of the density profile vanishes. By analogy with the liquid-vapor interface and the analysis of the adsorption this behavior is suggested to be strongly related to the drying transition.

Electric double-layer capacitance between an ionic liquid and few-layer graphene.

PubMed

Uesugi, Eri; Goto, Hidenori; Eguchi, Ritsuko; Fujiwara, Akihiko; Kubozono, Yoshihiro

2013-01-01

Ionic-liquid gates have a high carrier density due to their atomically thin electric double layer (EDL) and extremely large geometrical capacitance Cg. However, a high carrier density in graphene has not been achieved even with ionic-liquid gates because the EDL capacitance CEDL between the ionic liquid and graphene involves the series connection of Cg and the quantum capacitance Cq, which is proportional to the density of states. We investigated the variables that determine CEDL at the molecular level by varying the number of graphene layers n and thereby optimising Cq. The CEDL value is governed by Cq at n < 4, and by Cg at n > 4. This transition with n indicates a composite nature for CEDL. Our finding clarifies a universal principle that determines capacitance on a microscopic scale, and provides nanotechnological perspectives on charge accumulation and energy storage using an ultimately thin capacitor.

Electric double-layer capacitance between an ionic liquid and few-layer graphene

PubMed Central

Uesugi, Eri; Goto, Hidenori; Eguchi, Ritsuko; Fujiwara, Akihiko; Kubozono, Yoshihiro

2013-01-01

Ionic-liquid gates have a high carrier density due to their atomically thin electric double layer (EDL) and extremely large geometrical capacitance Cg. However, a high carrier density in graphene has not been achieved even with ionic-liquid gates because the EDL capacitance CEDL between the ionic liquid and graphene involves the series connection of Cg and the quantum capacitance Cq, which is proportional to the density of states. We investigated the variables that determine CEDL at the molecular level by varying the number of graphene layers n and thereby optimising Cq. The CEDL value is governed by Cq at n < 4, and by Cg at n > 4. This transition with n indicates a composite nature for CEDL. Our finding clarifies a universal principle that determines capacitance on a microscopic scale, and provides nanotechnological perspectives on charge accumulation and energy storage using an ultimately thin capacitor. PMID:23549208

Novel electrospun gas diffusion layers for polymer electrolyte membrane fuel cells: Part II. In operando synchrotron imaging for microscale liquid water transport characterization

NASA Astrophysics Data System (ADS)

Chevalier, S.; Ge, N.; Lee, J.; George, M. G.; Liu, H.; Shrestha, P.; Muirhead, D.; Lavielle, N.; Hatton, B. D.; Bazylak, A.

2017-06-01

This is the second paper in a two-part series in which we investigate the impact of the gas diffusion layer structure on the liquid water distribution in an operating polymer electrolyte membrane (PEM) fuel cell through the procedures of design, fabrication, and testing of novel hydrophobic electrospun gas diffusion layers (eGDLs). In this work, fibre diameters and alignment in eGDLs are precisely controlled, and concurrent synchrotron X-ray radiography and electrochemical impedance spectroscopy (EIS) are used to evaluate the influence of the controlled eGDL parameters on the liquid water distribution and on membrane liquid water content. For eGDLs with small fibre diameters (150-200 nm) and correspondingly smaller pore sizes, reduced liquid water accumulation under the flow field ribs is observed. However, more liquid water is pinned onto the eGDL - at the interface with flow field channels. Orienting fibre alignment perpendicular to the flow field channel direction leads to improved eGDL-catalyst layer contact and prevents rib-channel membrane deformation. On the other hand, eGDLs facilitate significant membrane dry-out, even under highly humidified operating conditions at high current densities.

Research on liquid impact forming technology of double-layered tubes

NASA Astrophysics Data System (ADS)

Sun, Changying; Liu, Jianwei; Yao, Xinqi; Huang, Beixing; Li, Yuhan

2018-03-01

A double-layered tube is widely used and developed in various fields because of its perfect comprehensive performance and design. With the advent of the era of a double-layered tube, the requirements for double layered tube forming quality, manufacturing cost and forming efficiency are getting higher, so forming methods of a double-layered tube are emerged in an endless stream, the forming methods of a double-layered tube have a great potential in the future. The liquid impact forming technology is a combination of stamping technology and hydroforming technology. Forming a double-layered tube has huge advantages in production cost, quality and efficiency.

D 2 and DT Liquid-Layer Target Shots on NIF

DOE Office of Scientific and Technical Information (OSTI.GOV)

Walters, Curtis; Alger, Ethan; Bhandarkar, Suhas

Experiments at the National Ignition Facility (NIF) using targets containing a Deuterium-Tritium (DT) fuel layer have, until recently, required that a high-quality layer of solid deuterium-tritium (herein referred to as an "ice-layer") be formed in the capsule. The development of a process to line the inner surface of a target capsule with a foam layer of a thickness that is typical of icelayers has resulted in the ability to field targets with liquid layers wetting the foam. Successful fielding of liquid-layer targets on NIF required not only a foam lined capsule, but also changes to the capsule filling process andmore » the manner with which the inventory is maintained in the capsule. Additionally, changes to target heater power and the temperature drops across target components were required in order to achieve the desired range of shot temperatures. These changes, and the target's performance during four target shots on NIF will be discussed.« less

Absorbent product to absorb fluids. [for collection of human wastes

NASA Technical Reports Server (NTRS)

Dawn, F. S.; Correale, J. V. (Inventor)

1982-01-01

A multi-layer absorbent product for use in contact with the skin to absorb fluids is discussed. The product utilizes a water pervious facing layer for contacting the skin, overlayed by a first fibrous wicking layer, the wicking layer preferably being of the one-way variety in which fluid or liquid is moved away from the facing layer. The product further includes a first container section defined by inner and outer layer of a water pervious wicking material between which is disposed a first absorbent mass. A second container section defined by inner and outer layers between which is disposed a second absorbent mass and a liquid impermeable/gas permeable layer. Spacesuit applications are discussed.

The Effect of Martian Dust on Radiator Performance

NASA Technical Reports Server (NTRS)

Hollingsworth, D. Keith; Witte, Larry C.; Hinke, Jaime; Hulbert, Kathryn

2004-01-01

Experiments were performed in which the effective emittance of three types of radiator Coatings was measured as Martian dust simulant was added to the radiator face. The apparatus consisted of multiple radiator coupons on which Carbondale Red Clay dust was deposited. The coupons were powered by electric heaters, using a guard-heating configuration to achieve the accuracy required for acceptable emittance calculations. The apparatus was containing in a vacuum chamber that featured a liquid-nitrogen cooled shroud that simulated the Martian sky temperature. Radiator temperatures ranged from 250 to 350 K with sky temperatures from 185 to 248 K. Results show that as dust was added to the radiator surfaces, the effective emittance of the high - emittance coatings decreased from near 0.9 to a value of about 0.5. A low-emittance control surface, polished aluminum, demonstrated a rise in effective emittance for thin dust layers, and then a decline as the dust layer thickened. This behavior is attributed to the conductive resistance caused by the dust layer.

Retinal optical coherence tomography at 1 μm with dynamic focus control and axial motion tracking

NASA Astrophysics Data System (ADS)

Cua, Michelle; Lee, Sujin; Miao, Dongkai; Ju, Myeong Jin; Mackenzie, Paul J.; Jian, Yifan; Sarunic, Marinko V.

2016-02-01

High-resolution optical coherence tomography (OCT) retinal imaging is important to noninvasively visualize the various retinal structures to aid in better understanding of the pathogenesis of vision-robbing diseases. However, conventional OCT systems have a trade-off between lateral resolution and depth-of-focus. In this report, we present the development of a focus-stacking OCT system with automatic focus optimization for high-resolution, extended-focal-range clinical retinal imaging by incorporating a variable-focus liquid lens into the sample arm optics. Retinal layer tracking and selection was performed using a graphics processing unit accelerated processing platform for focus optimization, providing real-time layer-specific en face visualization. After optimization, multiple volumes focused at different depths were acquired, registered, and stitched together to yield a single, high-resolution focus-stacked dataset. Using this system, we show high-resolution images of the retina and optic nerve head, from which we extracted clinically relevant parameters such as the nerve fiber layer thickness and lamina cribrosa microarchitecture.

Retinal optical coherence tomography at 1 μm with dynamic focus control and axial motion tracking.

PubMed

Cua, Michelle; Lee, Sujin; Miao, Dongkai; Ju, Myeong Jin; Mackenzie, Paul J; Jian, Yifan; Sarunic, Marinko V

2016-02-01

High-resolution optical coherence tomography (OCT) retinal imaging is important to noninvasively visualize the various retinal structures to aid in better understanding of the pathogenesis of vision-robbing diseases. However, conventional OCT systems have a trade-off between lateral resolution and depth-of-focus. In this report, we present the development of a focus-stacking OCT system with automatic focus optimization for high-resolution, extended-focal-range clinical retinal imaging by incorporating a variable-focus liquid lens into the sample arm optics. Retinal layer tracking and selection was performed using a graphics processing unit accelerated processing platform for focus optimization, providing real-time layer-specific en face visualization. After optimization, multiple volumes focused at different depths were acquired, registered, and stitched together to yield a single, high-resolution focus-stacked dataset. Using this system, we show high-resolution images of the retina and optic nerve head, from which we extracted clinically relevant parameters such as the nerve fiber layer thickness and lamina cribrosa microarchitecture.

In situ creation of reactive polymer nanoparticles and resulting polymer layers formed at the interfaces of liquid crystals (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kang, Shin-Woong; Kundu, Sudarshan; Park, Heung-Shik; Oh, Keun Chan; Lyu, Jae Jin

2017-02-01

We report the in situ creation of reactive polymer nanoparticles and resulting polymer networks formed at the interfaces of liquid crystals. It is known that polymerization-induced phase separation proceeds in two distinct regimes depending on the concentration of monomer. For a high monomer concentration, phase separation occurs mainly through the spinodal decomposition process, consequently resulting in interpenetrating polymer networks. For a dilute system, however, the phase separation mainly proceeds and completes in the binodal decomposition regime. The system resembles the aggregation process of colloidal particle. In this case, the reaction kinetics is limited by the reaction between in situ created polymer aggregates and hence the network morphologies are greatly influenced by the diffusion of reactive polymer particles. The thin polymer layers localized at the surface of substrate are inevitably observed and can be comprehended by the interfacial adsorption and further cross-linking reaction of reactive polymer aggregates at the interface. This process provides a direct perception on understanding polymer stabilized liquid crystals accomplished by the interfacial polymer layer. The detailed study has been performed for an extremely dilute condition (below 0.5 wt%) by employing systematic experimental approaches. Creation and growth of polymer nanoparticles have been measured by particle size analyzer. The interfacial localization of polymer aggregates and resulting interfacial layer formation with a tens of nanometer scale have been exploited at various interfaces such as liquid-solid, liquid-liquid, and liquid-gas interfaces. The resulting interfacial layers have been characterized by using fuorescent confocal microscope and field emission scanning electron microscope. The detailed processes of the polymer stabilized vertically aligned liquid crystals will be discussed in support of the reported study.

Biocide squirting from an elastomeric tri-layer film.

PubMed

Sonntag, Philippe; Hoerner, Pierre; Cheymol, André; Argy, Gilles; Riess, Gérard; Reiter, Günter

2004-05-01

Protective layers typically act in a passive way by simply separating two sides. Protection is only efficient as long as the layers are intact. If a high level of protection has to be achieved by thin layers, complementary measures need to be in place to ensure safety, even after breakage of the layer-an important issue in medical applications. Here, we present a novel approach for integrating a biocide liquid into a protective film (about 300-500 microm thick), which guarantees that a sufficient amount of biocide is rapidly released when the film is punctured. The film is composed of a middle layer, containing the liquid in droplet-like compartments, sandwiched between two elastomeric boundary layers. When the film is punctured, the liquid squirts out of the middle layer. A theoretical model was used to determine the size and density of droplets that are necessary to ensure a sufficient quantity of biocide is expelled from an adequately elastic matrix to provide protection at the site of damage. We demonstrate the utility of this approach for the fabrication of surgical gloves.

Accurate Measurement of the Optical Constants n and k for a Series of 57 Inorganic and Organic Liquids for Optical Modeling and Detection.

PubMed

Myers, Tanya L; Tonkyn, Russell G; Danby, Tyler O; Taubman, Matthew S; Bernacki, Bruce E; Birnbaum, Jerome C; Sharpe, Steven W; Johnson, Timothy J

2018-04-01

For optical modeling and other purposes, we have created a library of 57 liquids for which we have measured the complex optical constants n and k. These liquids vary in their nature, ranging in properties that include chemical structure, optical band strength, volatility, and viscosity. By obtaining the optical constants, one can model most optical phenomena in media and at interfaces including reflection, refraction, and dispersion. Based on the works of others, we have developed improved protocols using multiple path lengths to determine the optical constants n/k for dozens of liquids, including inorganic, organic, and organophosphorus compounds. Detailed descriptions of the measurement and data reduction protocols are discussed; agreement of the derived optical constant n and k values with literature values are presented. We also present results using the n/k values as applied to an optical modeling scenario whereby the derived data are presented and tested for models of 1 µm and 100 µm layers for dimethyl methylphosphonate (DMMP) on both metal (aluminum) and dielectric (soda lime glass) substrates to show substantial differences between the reflected signal from highly reflective substrates and less-reflective substrates.

The effect of surface alignment on analog control of director rotation in polarization stiffened SmC* devices

NASA Astrophysics Data System (ADS)

Reznikov, Mitya; Lopatina, Lena M.; O'Callaghan, Michael J.; Bos, Philip J.

2011-03-01

The effect of surface alignment on the achievement of analog ("V"-shaped) electric field control of director rotation in SmC* liquid crystal devices is investigated experimentally and through numerical modeling. Ferroelectric SmC* liquid crystals are intrinsically analog and thresholdless, i.e. the director can be rotated freely around the tilt cone. Whether or not a SmC* liquid crystal cell exhibits thresholdless switching depends strongly on the influence of the cell's alignment layers, on the magnitude of the liquid crystal's spontaneous polarization, and on whether smectic layers adopt a bookshelf or chevron configuration. To study the effect of the surface alignment layers, we have exploited a technique for the vertical (bookshelf) alignment of the smectic layers that does not depend on surface anisotropy. The alignment technique allows an experimental study of the influence of surfaces spanning a wide range of pretilt angles, azimuthal and zenithal anchoring energies. This technique is used to study the effect of surfaces on the threshold behavior of director rotation in SmC* materials under the influence of an electric field. The alignment technique also allowed us to use a high-PS liquid crystal material having an I-A-C phase sequence and reduced layer shrinkage thought to be well suited to thresholdless switching. We show that the alignment layer has a strong effect, and that excellent analog response can be achieved for the case of alignment layers which promote homeotropic director orientation. We further model and discuss the potential effect of a thin layer of nematic at the surface and the possibility of gliding of the easy axis during switching.

Measurement of the oxygen mass transfer through the air-water interface.

PubMed

Mölder, Erik; Mashirin, Alelxei; Tenno, Toomas

2005-01-01

Gas mass transfer through the liquid-gas interface has enormous importance in various natural and industrial processes. Surfactants or insoluble compounds adsorbed onto an interface will inhibit the gas mass transfer through the liquid-gas surface. This study presents a technique for measuring the oxygen mass transfer through the air-water interface. Experimental data obtained with the measuring device were incorporated into a novel mathematical model, which allowed one to calculate diffusion conduction of liquid surface layer and oxygen mass transfer coefficient in the liquid surface layer. A special measurement cell was constructed. The most important part of the measurement cell is a chamber containing the electrochemical oxygen sensor inside it. Gas exchange between the volume of the chamber and the external environment takes place only through the investigated surface layer. Investigated liquid was deoxygenated, which triggers the oxygen mass transfer from the chamber through the liquid-air interface into the liquid phase. The decrease of oxygen concentration in the cell during time was measured. By using this data it is possible to calculate diffusional parameters of the water surface layer. Diffusion conduction of oxygen through the air-water surface layer of selected wastewaters was measured. The diffusion conduction of different wastewaters was about 3 to 6 times less than in the unpolluted water surface. It was observed that the dilution of wastewater does not have a significant impact on the oxygen diffusion conduction through the wastewater surface layer. This fact can be explained with the presence of the compounds with high surface activity in the wastewater. Surfactants achieved a maximum adsorption and, accordingly, the maximum decrease of oxygen permeability already at a very low concentration of surfactants in the solution. Oxygen mass transfer coefficient of the surface layer of the water is found to be Ds/ls = 0.13 x 10(-3) x cm/s. A simple technique for measuring oxygen diffusion parameters through the air-water solution surface has been developed. Derived equations enable the calculation of diffusion parameters of the surface layer at current conditions. These values of the parameters permit one to compare the resistances of the gas-liquid interface to oxygen mass transfer in the case of adsorption of different substances on the surface layer. This simple technique may be used for a determination of oxygen permeability of different water-solution surface layers. It enables one to measure the resistance to the oxygen permeability of all inflowing wastewater surface layers in the wastewater treatment plant, and to initiate a preliminary cleaning of this wastewater if required. Similarly, we can measure oxygen permeability of natural waterbodies. Especially in the case of pollution, it is important to know to what extent the oxygen permeability of the water surface layer has been decreased. Based on the tehnique presented in this research, fieldwork equipment will be developed.

Calculations of electric currents in Europa

NASA Technical Reports Server (NTRS)

Colburn, D. S.; Reynolds, R. T.

1986-01-01

Electrical currents should flow in the Galilean satellite, Europa, because it is located in Jupiter's corotating magnetosphere. The possible magnitudes of these currents are calculated by assuming that Europa is a differentiated body consisting of an outer H2O layer and a silicate core. Two types of models are considered here: one in which the water is completely frozen and a second in which there is an intermediate liquid layer. For the transverse electric mode (eddy currents), the calculated current density in a liquid layer is approximately 10 to the -5/Am. For the transverse magnetic mode (unipolar generator), the calculated current density in the liquid is severely constrained by the ice layer to a range of only 10 to the -10 to -11th power/ Am, for a total H2O thickness of 100 km, provided that neither layer is less than 4 km thick. The current density is less for a completely frozen H2O layer. If transient cracks were to appear in the ice layer, thereby exposing liquid, the calculated current density could rise to a range of 10 to the -6 to 10 to the -5/Am, depending on layer thicknesses, which would require an exposed area of 10 to the -9 to 10 to the -8 of the Europa surface. The corresponding total current of 2.3x10 to the 5th power A could in 1 yr. electrolyze 7x10 to the 5th power kg of water (and more if the cells were in series), and thereby store up to 10 the 8th power J of energy, but it is not clear how electrolysis can take place in the absence of suitable electrodes. Electrical heating would be significant only if the ice-layer thickness were on the order of 1 m, such as might occur if an exposed liquid surface were to freeze over; the heating under this condition could hinder the thickening of the ice layer.

A molecular dynamics study of freezing in a confined geometry

NASA Technical Reports Server (NTRS)

Ma, Wen-Jong; Banavar, Jayanth R.; Koplik, Joel

1992-01-01

The dynamics of freezing of a Lennard-Jones liquid in narrow channels bounded by molecular walls is studied by computer simulation. The time development of ordering is quantified and a novel freezing mechanism is observed. The liquid forms layers and subsequent in-plane ordering within a layer is accompanied by a sharpening of the layer in the transverse direction. The effects of channel size, the methods of quench, the liquid-wall interaction and the roughness of walls on the freezing mechanism are elucidated. Comparison with recent experiments on freezing in confined geometries is presented.

Understanding rapid changes in phase partitioning between cloud liquid and ice in an Arctic stratiform mixed-phase cloud

NASA Astrophysics Data System (ADS)

Kalesse, Heike; de Boer, Gijs; Solomon, Amy; Oue, Mariko; Ahlgrimm, Maike; Zhang, Damao; Shupe, Matthew; Luke, Edward; Protat, Alain

2016-04-01

In the Arctic, a region particularly sensitive to climate change, mixed-phase clouds occur as persistent single or multiple stratiform layers. For many climate models, the correct partitioning of hydrometeor phase (liquid vs. ice) remains a challenge. However, this phase partitioning plays an important role for precipitation processes and the radiation budget. To better understand the partitioning of phase in Arctic clouds, observations using a combination of surface-based remote sensors are useful. In this study, the focus is on a persistent low-level single-layer stratiform Arctic mixed-phase cloud observed during March 11-12, 2013 at the US Department of Energy's (DOE) Atmospheric Radiation Measurement (ARM) North Slope of Alaska (NSA) permanent site in Barrow, Alaska. This case is of particular interest due to two significant shifts in observed precipitation intensity over a 36 hour period. For the first 12 hours of this case, the observed liquid portion of the cloud cover featured a stable cloud top height with a gradually descending liquid cloud base and continuous ice precipitation. Then the ice precipitation intensity significantly decreased. A second decrease in ice precipitation intensity was observed a few hours later coinciding with the advection of a cirrus over the site. Through analysis of the data collected by extensive ground-based remote-sensing and in-situ observing systems as well as Nested Weather Research and Forecasting (WRF) simulations and ECMWF radiation scheme simulations, we try to shed light on the processes responsible for these rapid changes in precipitation rates. A variety of parameters such as the evolution of the internal dynamics and microphysics of the low-level mixed-phase cloud and the influence of the cirrus cloud are evaluated.

Surface tension and quasi-emulsion of cavitation bubble cloud.

PubMed

Bai, Lixin; Chen, Xiaoguang; Zhu, Gang; Xu, Weilin; Lin, Weijun; Wu, Pengfei; Li, Chao; Xu, Delong; Yan, Jiuchun

2017-03-01

A quasi-emulsion phenomenon of cavitation structure in a thin liquid layer (the thin liquid layer is trapped between a radiating surface and a hard reflector) is investigated experimentally with high-speed photography. The transformation from cloud-in-water (c/w) emulsion to water-in-cloud (w/c) emulsion is related to the increase of cavitation bubble cloud. The acoustic field in the thin liquid layer is analyzed. It is found that the liquid region has higher acoustic pressure than the cloud region. The bubbles are pushed from liquid region to cloud region by the primary Bjerknes forces. The rate of change of CSF increased with the increase of CSF. The cavitation bubbles on the surface of cavitation cloud are attracted by the cavitation bubbles inside the cloud due to secondary Bjerknes forces. The existence of surface tension on the interface of liquid region and cloud region is proved. The formation mechanism of disc-shaped liquid region and cloud region are analysed by surface tension and incompressibility of cavitation bubble cloud. Copyright © 2016 Elsevier B.V. All rights reserved.

Measurement of high-pressure shock waves in cryogenic deuterium-tritium ice layered capsule implosions on NIF.

PubMed

Robey, H F; Moody, J D; Celliers, P M; Ross, J S; Ralph, J; Le Pape, S; Berzak Hopkins, L; Parham, T; Sater, J; Mapoles, E R; Holunga, D M; Walters, C F; Haid, B J; Kozioziemski, B J; Dylla-Spears, R J; Krauter, K G; Frieders, G; Ross, G; Bowers, M W; Strozzi, D J; Yoxall, B E; Hamza, A V; Dzenitis, B; Bhandarkar, S D; Young, B; Van Wonterghem, B M; Atherton, L J; Landen, O L; Edwards, M J; Boehly, T R

2013-08-09

The first measurements of multiple, high-pressure shock waves in cryogenic deuterium-tritium (DT) ice layered capsule implosions on the National Ignition Facility have been performed. The strength and relative timing of these shocks must be adjusted to very high precision in order to keep the DT fuel entropy low and compressibility high. All previous measurements of shock timing in inertial confinement fusion implosions [T. R. Boehly et al., Phys. Rev. Lett. 106, 195005 (2011), H. F. Robey et al., Phys. Rev. Lett. 108, 215004 (2012)] have been performed in surrogate targets, where the solid DT ice shell and central DT gas regions were replaced with a continuous liquid deuterium (D2) fill. This report presents the first experimental validation of the assumptions underlying this surrogate technique.

Kelvin-Helmholtz instability of a thin liquid sheet: Effect of the gas-boundary layer

NASA Astrophysics Data System (ADS)

Tirumkudulu, Mahesh

2017-11-01

It is well known that when a thin liquid sheet moves with respect to a surrounding gas phase, the liquid sheet is susceptible to the Kelvin-Helmholtz instability. Here, flow in both the liquid and the gas phases are assumed to be inviscid. In this work, we include exactly via a perturbation analysis, the influence of the growing boundary layer in the gas phase in the base flow and show that both temporal and spatial growth rates obtained from the linear stability analysis are significantly reduced due to the presence of the boundary layer. These results are in line with the simulation results of Lozano et al. and Tammisola et al.. We conclude with the implication of these results on the break-up of radially expanding liquid sheets. Funding from IIT Bombay, CSIR India, and Trinity College, Cambridge University is acknowledged.

Capillary condenser/evaporator

NASA Technical Reports Server (NTRS)

Valenzuela, Javier A. (Inventor)

2010-01-01

A heat transfer device is disclosed for transferring heat to or from a fluid that is undergoing a phase change. The heat transfer device includes a liquid-vapor manifold in fluid communication with a capillary structure thermally connected to a heat transfer interface, all of which are disposed in a housing to contain the vapor. The liquid-vapor manifold transports liquid in a first direction and conducts vapor in a second, opposite direction. The manifold provides a distributed supply of fluid (vapor or liquid) over the surface of the capillary structure. In one embodiment, the manifold has a fractal structure including one or more layers, each layer having one or more conduits for transporting liquid and one or more openings for conducting vapor. Adjacent layers have an increasing number of openings with decreasing area, and an increasing number of conduits with decreasing cross-sectional area, moving in a direction toward the capillary structure.

Alternative hot spot formation techniques using liquid deuterium-tritium layer inertial confinement fusion capsules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olson, R. E.; Leeper, R. J.

2013-09-27

The baseline DT ice layer inertial confinement fusion (ICF) ignition capsule design requires a hot spot convergence ratio of ~34 with a hot spot that is formed from DT mass originally residing in a very thin layer at the inner DT ice surface. In the present paper, we propose alternative ICF capsule designs in which the hot spot is formed mostly or entirely from mass originating within a spherical volume of DT vapor. Simulations of the implosion and hot spot formation in two DT liquid layer ICF capsule concepts—the DT wetted hydrocarbon (CH) foam concept and the “fast formed liquid”more » (FFL) concept—are described and compared to simulations of standard DT ice layer capsules. 1D simulations are used to compare the drive requirements, the optimal shock timing, the radial dependence of hot spot specific energy gain, and the hot spot convergence ratio in low vapor pressure (DT ice) and high vapor pressure (DT liquid) capsules. 2D simulations are used to compare the relative sensitivities to low-mode x-ray flux asymmetries in the DT ice and DT liquid capsules. It is found that the overall thermonuclear yields predicted for DT liquid layer capsules are less than yields predicted for DT ice layer capsules in simulations using comparable capsule size and absorbed energy. However, the wetted foam and FFL designs allow for flexibility in hot spot convergence ratio through the adjustment of the initial cryogenic capsule temperature and, hence, DT vapor density, with a potentially improved robustness to low-mode x-ray flux asymmetry.« less

Alternative hot spot formation techniques using liquid deuterium-tritium layer inertial confinement fusion capsules

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olson, R. E.; Leeper, R. J.

2013-09-15

The baseline DT ice layer inertial confinement fusion (ICF) ignition capsule design requires a hot spot convergence ratio of ∼34 with a hot spot that is formed from DT mass originally residing in a very thin layer at the inner DT ice surface. In the present paper, we propose alternative ICF capsule designs in which the hot spot is formed mostly or entirely from mass originating within a spherical volume of DT vapor. Simulations of the implosion and hot spot formation in two DT liquid layer ICF capsule concepts—the DT wetted hydrocarbon (CH) foam concept and the “fast formed liquid”more » (FFL) concept—are described and compared to simulations of standard DT ice layer capsules. 1D simulations are used to compare the drive requirements, the optimal shock timing, the radial dependence of hot spot specific energy gain, and the hot spot convergence ratio in low vapor pressure (DT ice) and high vapor pressure (DT liquid) capsules. 2D simulations are used to compare the relative sensitivities to low-mode x-ray flux asymmetries in the DT ice and DT liquid capsules. It is found that the overall thermonuclear yields predicted for DT liquid layer capsules are less than yields predicted for DT ice layer capsules in simulations using comparable capsule size and absorbed energy. However, the wetted foam and FFL designs allow for flexibility in hot spot convergence ratio through the adjustment of the initial cryogenic capsule temperature and, hence, DT vapor density, with a potentially improved robustness to low-mode x-ray flux asymmetry.« less

Attenuation of the Acoustic Signal Propagating Through a Bubbly Liquid Layer

NASA Astrophysics Data System (ADS)

Gubaidullin, D. A.; Nikiforov, A. A.

2018-01-01

The acoustic signal dynamics in a five-layer medium containing two liquid layers with polydisperse gas bubbles has been investigated. Calculations have been made for the interaction between the pulse perturbation of smallamplitude pressure and a multilayer sample containing two layers of industrial gel with polydisperse air bubbles. It has been shown that a small content of bubbles (about 0.1 vol. %) in a thin gel layer decreases tenfold or more the amplitude of acoustic waves with frequencies close to the resonance frequency of natural oscillations of bubbles. There are frequency ranges thereby where the influence of the bubbly layer is insignificant.

RETENTION OF LIQUID CONTAMINANTS IN LAYERED SOILS. (R825549C063)

EPA Science Inventory

Observations of organic contaminant liquids retained in layered soil profiles indicate contaminant saturations much greater than residual, where residual saturation would be expected, if one assumes a static distribution of fluid pressure. It is theorized that the increased re...

Determination of Surface Potential and Electrical Double-Layer Structure at the Aqueous Electrolyte-Nanoparticle Interface

NASA Astrophysics Data System (ADS)

Brown, Matthew A.; Abbas, Zareen; Kleibert, Armin; Green, Richard G.; Goel, Alok; May, Sylvio; Squires, Todd M.

2016-01-01

The structure of the electrical double layer has been debated for well over a century, since it mediates colloidal interactions, regulates surface structure, controls reactivity, sets capacitance, and represents the central element of electrochemical supercapacitors. The surface potential of such surfaces generally exceeds the electrokinetic potential, often substantially. Traditionally, a Stern layer of nonspecifically adsorbed ions has been invoked to rationalize the difference between these two potentials; however, the inability to directly measure the surface potential of dispersed systems has rendered quantitative measurements of the Stern layer potential, and other quantities associated with the outer Helmholtz plane, impossible. Here, we use x-ray photoelectron spectroscopy from a liquid microjet to measure the absolute surface potentials of silica nanoparticles dispersed in aqueous electrolytes. We quantitatively determine the impact of specific cations (Li+ , Na+ , K+ , and Cs+ ) in chloride electrolytes on the surface potential, the location of the shear plane, and the capacitance of the Stern layer. We find that the magnitude of the surface potential increases linearly with the hydrated-cation radius. Interpreting our data using the simplest assumptions and most straightforward understanding of Gouy-Chapman-Stern theory reveals a Stern layer whose thickness corresponds to a single layer of water molecules hydrating the silica surface, plus the radius of the hydrated cation. These results subject electrical double-layer theories to direct and falsifiable tests to reveal a physically intuitive and quantitatively verified picture of the Stern layer that is consistent across multiple electrolytes and solution conditions.

Instabilities of Shallow Dynamic Thermocapillary Liquid Layers

NASA Technical Reports Server (NTRS)

Schwabe, D.; Moeller, U.; Schneider, J.; Scharmann, A.

1992-01-01

In the experiments reported here, correlation measurements with three fixed thermocouples and direct optical observations of the dynamically deformed liquid-gas interface were used to study the spatiotemporal structure of stable and unstable thermocapillary flows. The frequency, wavelength, phase speed, angle of propagation, and stability limits are reported for two geometrically different configurations of thermocapillary flow in side-heated thin liquid layers. A theoretical interpretation of the results is presented.

Flash evaporation of liquid monomer particle mixture

DOEpatents

Affinito, John D.; Darab, John G.; Gross, Mark E.

1999-01-01

The present invention is a method of making a first solid composite polymer layer. The method has the steps of (a) mixing a liquid monomer with particles substantially insoluble in the liquid monomer forming a monomer particle mixture; (b) flash evaporating the particle mixture and forming a composite vapor; and (c) continuously cryocondensing said composite vapor on a cool substrate and cross-linking the cryocondensed film thereby forming the polymer layer.

Surface structure evolution in a homologous series of ionic liquids.

PubMed

Haddad, Julia; Pontoni, Diego; Murphy, Bridget M; Festersen, Sven; Runge, Benjamin; Magnussen, Olaf M; Steinrück, Hans-Georg; Reichert, Harald; Ocko, Benjamin M; Deutsch, Moshe

2018-02-06

Interfaces of room temperature ionic liquids (RTILs) are important for both applications and basic science and are therefore intensely studied. However, the evolution of their interface structure with the cation's alkyl chain length [Formula: see text] from Coulomb to van der Waals interaction domination has not yet been studied for even a single broad homologous RTIL series. We present here such a study of the liquid-air interface for [Formula: see text], using angstrom-resolution X-ray methods. For [Formula: see text], a typical "simple liquid" monotonic surface-normal electron density profile [Formula: see text] is obtained, like those of water and organic solvents. For [Formula: see text], increasingly more pronounced nanoscale self-segregation of the molecules' charged moieties and apolar chains yields surface layering with alternating regions of headgroups and chains. The layering decays into the bulk over a few, to a few tens, of nanometers. The layering periods and decay lengths, their linear [Formula: see text] dependence, and slopes are discussed within two models, one with partial-chain interdigitation and the other with liquid-like chains. No surface-parallel long-range order is found within the surface layer. For [Formula: see text], a different surface phase is observed above melting. Our results also impact general liquid-phase issues like supramolecular self-aggregation and bulk-surface structure relations.

Anomalous temperature dependence of layer spacing of de Vries liquid crystals: Compensation model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Merkel, K.; Kocot, A.; Vij, J. K., E-mail: jvij@tcd.ie

Smectic liquid crystals that exhibit temperature independent layer thickness offer technological advantages for their use in displays and photonic devices. The dependence of the layer spacing in SmA and SmC phases of de Vries liquid crystals is found to exhibit distinct features. On entering the SmC phase, the layer thickness initially decreases below SmA to SmC (T{sub A–C}) transition temperature but increases anomalously with reducing temperature despite the molecular tilt increasing. This anomalous observation is being explained quantitatively. Results of IR spectroscopy show that layer shrinkage is caused by tilt of the mesogen's rigid core, whereas the expansion is causedmore » by the chains getting more ordered with reducing temperature. This mutual compensation arising from molecular fragments contributing to the layer thickness differs from the previous models. The orientational order parameter of the rigid core of the mesogen provides direct evidence for de Vries cone model in the SmA phase for the two compounds investigated.« less

Manipulating femtosecond pulse shape using liquid crystals infiltrated one-dimensional graded index photonic crystal waveguides composed of coupled-cavities

NASA Astrophysics Data System (ADS)

Fathollahi Khalkhali, T.; Bananej, A.

2017-10-01

In this paper, we investigate the transmission of a 10-femtosecond pulse through an ordinary and graded index coupled-cavity waveguide, using finite-difference time-domain and transfer matrix method. The ordinary structure is composed of dielectric/liquid crystal layers in which four defect layers are placed symmetrically. Next, we introduce a graded structure based on the ordinary system in which dielectric refractive index slightly increases with a constant step value from the beginning to the end of the structure while liquid crystal layers are maintained unchanged. Simulation results reveal that by applying an external static electric field and controlling liquid crystal refractive index in graded structure, it is possible to transmit an ultrashort pulse with negligible distortion and attenuation.

Crystallization, melting, and structure of water nanoparticles at atmospherically relevant temperatures.

PubMed

Johnston, Jessica C; Molinero, Valeria

2012-04-18

Water nanoparticles play an important role in atmospheric processes, yet their equilibrium and nonequilibrium liquid-ice phase transitions and the structures they form on freezing are not yet fully elucidated. Here we use molecular dynamics simulations with the mW water model to investigate the nonequilibrium freezing and equilibrium melting of water nanoparticles with radii R between 1 and 4.7 nm and the structure of the ice formed by crystallization at temperatures between 150 and 200 K. The ice crystallized in the particles is a hybrid form of ice I with stacked layers of the cubic and hexagonal ice polymorphs in a ratio approximately 2:1. The ratio of cubic ice to hexagonal ice is insensitive to the radius of the water particle and is comparable to that found in simulations of bulk water around the same temperature. Heating frozen particles that contain multiple crystallites leads to Ostwald ripening and annealing of the ice structures, accompanied by an increase in the amount of ice at the expense of the liquid water, before the particles finally melt from the hybrid ice I to liquid, without a transition to hexagonal ice. The melting temperatures T(m) of the nanoparticles are not affected by the ratio of cubic to hexagonal layers in the crystal. T(m) of the ice particles decreases from 255 to 170 K with the particle size and is well described by the Gibbs-Thomson equation, T(m)(R) = T(m)(bulk) - K(GT)/(R - d), with constant K(GT) = 82 ± 5 K·nm and a premelted liquid of width d = 0.26 ± 0.05 nm, about one monolayer. The freezing temperatures also decrease with the particles' radii. These results are important for understanding the composition, freezing, and melting properties of ice and liquid water particles under atmospheric conditions. © 2012 American Chemical Society

Leaping shampoo glides on a 500-nm-thick lubricating air layer

NASA Astrophysics Data System (ADS)

Li, Erqiang; Lee, Sanghyun; Marston, Jeremy; Bonito, Andrea; Thoroddsen, Sigurdur

2013-11-01

When a stream of shampoo is fed onto a pool in one's hand, a jet can leap sideways or rebound from the liquid surface in an intriguing phenomenon known as the Kaye effect. Earlier studies have debated whether non-Newtonian effects are the underlying cause of this phenomenon, making the jet glide on top of a shear-thinning liquid layer, or whether an entrained air layer is responsible. Herein we show unambiguously that the jet slides on a lubricating air layer [Lee et al., Phys. Rev. E 87, 061001 (2013)]. We identify this layer by looking through the pool liquid and observing its rupture into fine micro-bubbles. The resulting micro-bubble sizes suggest that the thickness of this air layer is around 500 nm. This thickness estimate is also supported by the tangential deceleration of the jet during the rebounding, with the shear stress within the thin air layer sufficient for the observed deceleration. Particle tracking within the jet shows uniform velocity, with no pronounced shear, which would be required for shear-thinning effects. The role of the surfactant may primarily be to stabilize the air film.

Catalytic hydrotreating process

DOEpatents

Karr, Jr., Clarence; McCaskill, Kenneth B.

1978-01-01

Carbonaceous liquids boiling above about 300.degree. C such as tars, petroleum residuals, shale oils and coal-derived liquids are catalytically hydrotreated by introducing the carbonaceous liquid into a reaction zone at a temperature in the range of 300.degree. to 450.degree. C and a pressure in the range of 300 to 4000 psig for effecting contact between the carbonaceous liquid and a catalytic transition metal sulfide in the reaction zone as a layer on a hydrogen permeable transition metal substrate and then introducing hydrogen into the reaction zone by diffusing the hydrogen through the substrate to effect the hydrogenation of the carbonaceous liquid in the presence of the catalytic sulfide layer.

A Direct Numerical Simulation of a Temporally Evolving Liquid-Gas Turbulent Mixing Layer

NASA Astrophysics Data System (ADS)

Vu, Lam Xuan; Chiodi, Robert; Desjardins, Olivier

2017-11-01

Air-blast atomization occurs when streams of co-flowing high speed gas and low speed liquid shear to form drops. Air-blast atomization has numerous industrial applications from combustion engines in jets to sprays used for medical coatings. The high Reynolds number and dynamic pressure ratio of a realistic air-blast atomization case requires large eddy simulation and the use of multiphase sub-grid scale (SGS) models. A direct numerical simulations (DNS) of a temporally evolving mixing layer is presented to be used as a base case from which future multiphase SGS models can be developed. To construct the liquid-gas mixing layer, half of a channel flow from Kim et al. (JFM, 1987) is placed on top of a static liquid layer that then evolves over time. The DNS is performed using a conservative finite volume incompressible multiphase flow solver where phase tracking is handled with a discretely conservative volume of fluid method. This study presents statistics on velocity and volume fraction at different Reynolds and Weber numbers.

The opto-thermal effect on encapsulated cholesteric liquid crystals

NASA Astrophysics Data System (ADS)

Liu, Yu-Sung; Lin, Hui-Chi; Yang, Kin-Min

2017-12-01

In this study, we implemented a micro-encapsulated CLC electronic paper that is optically addressed and electrically erasable. The mechanism that forms spot diameters on the CLC films is discussed and verified through various experimental parameters, including the thickness of CLCs and Poly(2,3-dihydrothieno-1,4-dioxin)-poly(styrenesulfonate) (PEDOT:PSS), pump intensity, and pumping time. The opto-thermal effect, brought on by the PEDOT:PSS absorbing layer, causes the spot diameters on the cholesteric liquid crystal thin films to vary. According to our results, the spot diameter is larger for a sample with a thinner cholesteric liquid crystal layer with the same excitation conditions and same thickness of the PEDOT layer. The spot diameter is also larger for a sample with a thicker PEDOT under the same excitation conditions and same thickness of the cholesteric liquid crystal layer. We proposed a simple heat-conducting model to explain the experimental results, which qualitatively agree with this theoretical model.

Wafer-scale two-dimensional semiconductors from printed oxide skin of liquid metals

NASA Astrophysics Data System (ADS)

Carey, Benjamin J.; Ou, Jian Zhen; Clark, Rhiannon M.; Berean, Kyle J.; Zavabeti, Ali; Chesman, Anthony S. R.; Russo, Salvy P.; Lau, Desmond W. M.; Xu, Zai-Quan; Bao, Qiaoliang; Kevehei, Omid; Gibson, Brant C.; Dickey, Michael D.; Kaner, Richard B.; Daeneke, Torben; Kalantar-Zadeh, Kourosh

2017-02-01

A variety of deposition methods for two-dimensional crystals have been demonstrated; however, their wafer-scale deposition remains a challenge. Here we introduce a technique for depositing and patterning of wafer-scale two-dimensional metal chalcogenide compounds by transforming the native interfacial metal oxide layer of low melting point metal precursors (group III and IV) in liquid form. In an oxygen-containing atmosphere, these metals establish an atomically thin oxide layer in a self-limiting reaction. The layer increases the wettability of the liquid metal placed on oxygen-terminated substrates, leaving the thin oxide layer behind. In the case of liquid gallium, the oxide skin attaches exclusively to a substrate and is then sulfurized via a relatively low temperature process. By controlling the surface chemistry of the substrate, we produce large area two-dimensional semiconducting GaS of unit cell thickness (~1.5 nm). The presented deposition and patterning method offers great commercial potential for wafer-scale processes.

Wafer-scale two-dimensional semiconductors from printed oxide skin of liquid metals.

PubMed

Carey, Benjamin J; Ou, Jian Zhen; Clark, Rhiannon M; Berean, Kyle J; Zavabeti, Ali; Chesman, Anthony S R; Russo, Salvy P; Lau, Desmond W M; Xu, Zai-Quan; Bao, Qiaoliang; Kevehei, Omid; Gibson, Brant C; Dickey, Michael D; Kaner, Richard B; Daeneke, Torben; Kalantar-Zadeh, Kourosh

2017-02-17

A variety of deposition methods for two-dimensional crystals have been demonstrated; however, their wafer-scale deposition remains a challenge. Here we introduce a technique for depositing and patterning of wafer-scale two-dimensional metal chalcogenide compounds by transforming the native interfacial metal oxide layer of low melting point metal precursors (group III and IV) in liquid form. In an oxygen-containing atmosphere, these metals establish an atomically thin oxide layer in a self-limiting reaction. The layer increases the wettability of the liquid metal placed on oxygen-terminated substrates, leaving the thin oxide layer behind. In the case of liquid gallium, the oxide skin attaches exclusively to a substrate and is then sulfurized via a relatively low temperature process. By controlling the surface chemistry of the substrate, we produce large area two-dimensional semiconducting GaS of unit cell thickness (∼1.5 nm). The presented deposition and patterning method offers great commercial potential for wafer-scale processes.

Wafer-scale two-dimensional semiconductors from printed oxide skin of liquid metals

PubMed Central

Carey, Benjamin J.; Ou, Jian Zhen; Clark, Rhiannon M.; Berean, Kyle J.; Zavabeti, Ali; Chesman, Anthony S. R.; Russo, Salvy P.; Lau, Desmond W. M.; Xu, Zai-Quan; Bao, Qiaoliang; Kavehei, Omid; Gibson, Brant C.; Dickey, Michael D.; Kaner, Richard B.; Daeneke, Torben; Kalantar-Zadeh, Kourosh

2017-01-01

A variety of deposition methods for two-dimensional crystals have been demonstrated; however, their wafer-scale deposition remains a challenge. Here we introduce a technique for depositing and patterning of wafer-scale two-dimensional metal chalcogenide compounds by transforming the native interfacial metal oxide layer of low melting point metal precursors (group III and IV) in liquid form. In an oxygen-containing atmosphere, these metals establish an atomically thin oxide layer in a self-limiting reaction. The layer increases the wettability of the liquid metal placed on oxygen-terminated substrates, leaving the thin oxide layer behind. In the case of liquid gallium, the oxide skin attaches exclusively to a substrate and is then sulfurized via a relatively low temperature process. By controlling the surface chemistry of the substrate, we produce large area two-dimensional semiconducting GaS of unit cell thickness (∼1.5 nm). The presented deposition and patterning method offers great commercial potential for wafer-scale processes. PMID:28211538

One-step synthesis of layered yttrium hydroxides in immiscible liquid-liquid systems: Intercalation of sterically-bulky hydrophobic organic anions and doping of europium ions

NASA Astrophysics Data System (ADS)

Watanabe, Mebae; Fujihara, Shinobu

2014-02-01

Inorganic-organic layered rare-earth compounds were synthesized on the basis of a biphasic liquid-liquid system in one pot. Layered yttrium hydroxides (LYHs) were chosen as a host material for the intercalation of hydrophobic organic guest anions such as benzoate, sebacate, or laurate. In a typical synthesis, an organic phase dissolving carboxylic acid was placed in contact with an equal amount of an aqueous phase dissolving yttrium nitrate n-hydrate and urea. At elevated temperatures up to 80 °C, urea was hydrolyzed to release hydroxyl anions which were used to form yttrium hydroxide layers. LYHs were then precipitated with the intercalation of carboxylate anions delivered from the organic phase under the distribution law. The structure and the morphology of the LYHs could be modulated by the intercalated anions. Doped with Eu3+ ions, the LYHs exhibited red photoluminescence which was enhanced by the intercalated anions due to the antenna effect.

A case study of microphysical structures and hydrometeor phase in convection using radar Doppler spectra at Darwin, Australia

NASA Astrophysics Data System (ADS)

Riihimaki, L. D.; Comstock, J. M.; Luke, E.; Thorsen, T. J.; Fu, Q.

2017-07-01

To understand the microphysical processes that impact diabatic heating and cloud lifetimes in convection, we need to characterize the spatial distribution of supercooled liquid water. To address this observational challenge, ground-based vertically pointing active sensors at the Darwin Atmospheric Radiation Measurement site are used to classify cloud phase within a deep convective cloud. The cloud cannot be fully observed by a lidar due to signal attenuation. Therefore, we developed an objective method for identifying hydrometeor classes, including mixed-phase conditions, using k-means clustering on parameters that describe the shape of the Doppler spectra from vertically pointing Ka-band cloud radar. This approach shows that multiple, overlapping mixed-phase layers exist within the cloud, rather than a single region of supercooled liquid. Diffusional growth calculations show that the conditions for the Wegener-Bergeron-Findeisen process exist within one of these mixed-phase microstructures.

Annular core liquid-salt cooled reactor with multiple fuel and blanket zones

DOEpatents

Peterson, Per F.

2013-05-14

A liquid fluoride salt cooled, high temperature reactor having a reactor vessel with a pebble-bed reactor core. The reactor core comprises a pebble injection inlet located at a bottom end of the reactor core and a pebble defueling outlet located at a top end of the reactor core, an inner reflector, outer reflector, and an annular pebble-bed region disposed in between the inner reflector and outer reflector. The annular pebble-bed region comprises an annular channel configured for receiving pebble fuel at the pebble injection inlet, the pebble fuel comprising a combination of seed and blanket pebbles having a density lower than the coolant such that the pebbles have positive buoyancy and migrate upward in said annular pebble-bed region toward the defueling outlet. The annular pebble-bed region comprises alternating radial layers of seed pebbles and blanket pebbles.

Soft shape-adaptive gripping device made from artificial muscle

NASA Astrophysics Data System (ADS)

Hamburg, E.; Vunder, V.; Johanson, U.; Kaasik, F.; Aabloo, A.

2016-04-01

We report on a multifunctional four-finger gripper for soft robotics, suitable for performing delicate manipulation tasks. The gripping device is comprised of separately driven gripping and lifting mechanisms, both made from a separate single piece of smart material - ionic capacitive laminate (ICL) also known as artificial muscle. Compared to other similar devices the relatively high force output of the ICL material allows one to construct a device able to grab and lift objects exceeding multiple times its own weight. Due to flexible design of ICL grips, the device is able to adapt the complex shapes of different objects and allows grasping single or multiple objects simultaneously without damage. The performance of the gripper is evaluated in two different configurations: a) the ultimate grasping strength of the gripping hand; and b) the maximum lifting force of the lifting actuator. The ICL is composed of three main layers: a porous membrane consisting of non-ionic polymer poly(vinylidene fluoride-co-hexafluoropropene) (PVdF-HFP), ionic liquid 1-ethyl-3-methylimidazolium trifluoromethane-sulfonate (EMITFS), and a reinforcing layer of woven fiberglass cloth. Both sides of the membrane are coated with a carbonaceous electrode. The electrodes are additionally covered with thin gold layers, serving as current collectors. Device made of this material operates silently, requires low driving voltage (<3 V), and is suitable for performing tasks in open air environment.

Determination of T-2 toxin, HT-2 toxin, and three other type A trichothecenes in layer feed by high-performance liquid chromatography-tandem mass spectrometry (LC-MS/MS)--comparison of two sample preparation methods.

PubMed

Bernhardt, Katrin; Valenta, Hana; Kersten, Susanne; Humpf, Hans-Ulrich; Dänicke, Sven

2016-05-01

A sensitive method for the simultaneous determination of T-2 toxin, HT-2 toxin, neosolaniol, T-2 triol, and T-2 tetraol in layer feed using high-performance liquid chromatography coupled to triple quadrupole mass spectrometry in the positive ionization mode (LC-ESI-MS/MS) is described. Two fast and easy clean-up methods-with BondElut Mycotoxin and MycoSep 227 columns, respectively-were tested. The separation of the toxins was conducted on a Pursuit XRs Ultra 2.8 HPLC column using 0.13 mM ammonium acetate as eluent A and methanol as eluent B. Detection of the mycotoxins was carried out in the multiple reaction monitoring (MRM) mode using ammonium adducts as precursor ions. Quantification of all analytes was performed with d3-T-2 toxin as an internal standard. The clean-up method with MycoSep 227 columns gave slightly better results for layer feed compared to the method using BondElut Mycotoxin columns (MycoSep 227: recovery between 50 and 63%, BondElut Mycotoxin: recovery between 32 and 67%) and was therefore chosen as the final method. The limits of detection ranged between 0.9 and 7.5 ng/g depending on the mycotoxin. The method was developed for the analysis of layer feed used at carry-over experiments with T-2 toxin in laying hens. For carry-over experiments, it is necessary that the method includes not only T-2 toxin but also the potential metabolites in animal tissues HT-2 toxin, neosolaniol, T-2 triol, and T-2 tetraol which could naturally occur in cereals used as feed stuff as well.

The importance of ion size and electrode curvature on electrical double layers in ionic liquids.

PubMed

Feng, Guang; Qiao, Rui; Huang, Jingsong; Dai, Sheng; Sumpter, Bobby G; Meunier, Vincent

2011-01-21

Room-temperature ionic liquids (ILs) are an emerging class of electrolytes for supercapacitors. We investigate the effects of ion size and electrode curvature on the electrical double layers (EDLs) in two ILs 1-butyl-3-methylimidazolium chloride [BMIM][Cl] and 1-butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF(6)], using a combination of molecular dynamics (MD) and quantum density functional theory (DFT) simulations. The sizes of the counter-ion and co-ion affect the ion distribution and orientational structure of EDLs. The EDL capacitances near both planar and cylindrical electrodes were found to follow the order: [BMIM][Cl] (near the positive electrode) > [BMIM][PF(6)] (near the positive electrode) ≈ [BMIM][Cl] (near the negative electrode) ≈ [BMIM][PF(6)] (near the negative electrode). The EDL capacitance was also found to increase as the electrode curvature increases. These capacitance data can be fit to the Helmholtz model and the recently proposed exohedral electrical double-cylinder capacitor (xEDCC) model when the EDL thickness is properly parameterized, even though key features of the EDLs in ILs are not accounted for in these models. To remedy the shortcomings of existing models, we propose a "Multiple Ion Layers with Overscreening" (MILO) model for the EDLs in ILs that takes into account two critical features of such EDLs, i.e., alternating layering of counter-ions and co-ions and charge overscreening. The capacitance computed from the MILO model agrees well with the MD prediction. Although some input parameters of the MILO model must be obtained from MD simulations, the MILO model may provide a new framework for understanding many important aspects of EDLs in ILs (e.g., the variation of EDL capacitance with the electrode potential) that are difficult to interpret using classical EDL models and experiments.

Impact of micro-porous layer on liquid water distribution at the catalyst layer interface and cell performance in a polymer electrolyte membrane fuel cell

NASA Astrophysics Data System (ADS)

Tabe, Yutaka; Aoyama, Yusuke; Kadowaki, Kazumasa; Suzuki, Kengo; Chikahisa, Takemi

2015-08-01

In polymer electrolyte membrane fuel cells, a gas diffusion layer (GDL) with a micro-porous layer (MPL) gives better anti-flooding performance than GDLs without an MPL. To investigate the function and mechanism of the MPL to suppress water flooding, the liquid water distribution at the cathode catalyst layer (CL) surface are observed by a freezing method; in the method liquid water is immobilized in ice form by rapid freezing, followed by disassembling the cell for observations. The ice covered area is quantified by image processing and cells with and without an MPL are compared. The results show that the MPL suppresses water accumulation at the interface due to smaller pore size and finer contact with the CL, and this results in less water flooding. Investigation of ice formed after -10 °C cold start shutdowns and the temporary performance deterioration at ordinary temperatures also indicates a significant influence of the liquid water accumulating at the interface. The importance of the fine contact between CL and MPL, the relative absence of gaps, is demonstrated by a gas diffusion electrode (GDE) which is directly coated with catalyst ink on the surface of the MPL achieving finer contact of the layers.

Thermal performance of a liquid hydrogen tank multilayer insulation system at warm boundary temperatures of 630, 530, and 152 R

NASA Astrophysics Data System (ADS)

Stochl, Robert J.; Knoll, Richard H.

1991-06-01

The results are presented of a study conducted to obtain experimental heat transfer data on a liquid hydrogen tank insulated with 34 layers of MLI (multilayer insulation) for warm side boundary temperatures of 630, 530, and 150 R. The MLI system consisted of two blankets, each blanket made up of alternate layers of double silk net (16 layers) and double aluminized Mylar radiation shields (15 layers) contained between two cover sheets of Dacron scrim reinforced Mylar. The insulation system was designed for and installed on a 87.6 in diameter liquid hydrogen tank. Nominal layer density of the insulation blankets is 45 layers/in. The insulation system contained penetrations for structural support, plumbing, and electrical wiring that would be representative of a cryogenic spacecraft. The total steady state heat transfer rates into the test tank for shroud temperatures of 630, 530, 152 R were 164.4, 95.8, and 15.9 BTU/hr respectively. The noninsulation heat leaks into the tank (12 fiberglass support struts, tank plumbing, and instrumentation lines) represent between 13 to 17 pct. of the total heat input. The heat input values would translate to liquid H2 losses of 2.3, 1.3, and 0.2 pct/day, with the tank held at atmospheric pressure.

Thermal performance of a liquid hydrogen tank multilayer insulation system at warm boundary temperatures of 630, 530, and 152 R

NASA Astrophysics Data System (ADS)

Stochl, Robert J.; Knoll, Richard H.

1991-06-01

The results are presented of a study conducted to obtain experimental heat transfer data on a liquid hydrogen tank insulated with 34 layers of MLI (multilayer insulation) for warm side boundary temperatures of 630, 530, and 150 R. The MLI system consisted of two blankets, each blanket made up of alternate layers of double silk net (16 layers) and double aluminized Mylar radiation shields (15 layers) contained between two cover sheets of Dacron scrim reinforced Mylar. The insulation system was designed for and installed on an 87.6 in. diameter liquid hydrogen tank. Nominal layer density of the insulation blankets is 45 layers/in. The insulation system contained penetrations for structural support, plumbing, and electrical wiring that would be representative of a cryogenic spacecraft. The total steady state heat transfer rates into the test tank for shroud temperatures of 630, 530, 152 R were 164.4, 95.8, and 15.9 BTU/hr, respectively. The noninsulation heat leaks into the tank (12 fiberglass support struts, tank plumbing, and instrumentation lines) represent between 13 to 17 pct. of the total heat input. The heat input values would translate to liquid H2 losses of 2.3, 1.3, and 0.2 pct/day, with the tank held at atmospheric pressure.

Method of making and structure for monolithic optical circuits

NASA Technical Reports Server (NTRS)

Evanchuk, Vincent L. (Inventor)

1983-01-01

A method for making monolithic optical circuits, with related optical devices as required or desired, on a supporting surface (10) consists of coating the supporting surface with reflecting metal or cladding resin, spreading a layer of liquid radiation senstivie plastic (12) on the surface, exposing the liquid plastic with a mask (14) to cure it in a desired pattern of light conductors (16, 18, 20), washing away the unexposed liquid plastic, and coating the conductors thus formed with reflective metal or cladding resin. The index of refraction for the cladding (22) is selected to be lower than for the conductors so that light in the conductors will be reflected by the interface with the cladding. For multiple level conductors, as where one conductor must cross over another, the process may be repeated to fabricate a bridge with columns (24, 26) of conductors to the next level, and conductor (28) between the columns. For more efficient transfer of energy over the bridge, faces at 45.degree. may be formed to reflect light up and across the bridge.

Liquid flow cells having graphene on nitride for microscopy

DOEpatents

Adiga, Vivekananda P.; Dunn, Gabriel; Zettl, Alexander K.; Alivisatos, A. Paul

2016-09-20

This disclosure provides systems, methods, and apparatus related to liquid flow cells for microscopy. In one aspect, a device includes a substrate having a first and a second oxide layer disposed on surfaces of the substrate. A first and a second nitride layer are disposed on the first and second oxide layers, respectively. A cavity is defined in the first oxide layer, the first nitride layer, and the substrate, with the cavity including a third nitride layer disposed on walls of the substrate and the second oxide layer that define the cavity. A channel is defined in the second oxide layer. An inlet port and an outlet port are defined in the second nitride layer and in fluid communication with the channel. A plurality of viewports is defined in the second nitride layer. A first graphene sheet is disposed on the second nitride layer covering the plurality of viewports.

Structure and Dynamics of Freely Suspended Liquid Crystals

NASA Technical Reports Server (NTRS)

Clark, Noel A.

2004-01-01

Smectic liquid crystals are phases of rod shaped molecules organized into one dimensionally (1 D) periodic arrays of layers, each layer being between one and two molecular lengths thick. In the least ordered smectic phases, the smectics A and C, each layer is a two dimensional (2D) liquid. Additionally there are a variety of more ordered smectic phases having hexatic short range translational order or 2D crystalline or quasi long range translational order within the layers. The inherent fluid-layer structure and low vapor pressure of smectic liquid crystals enables the long term stabilization of freely suspended, single component, layered fluid films as thin as 30A, a single molecular layer. The layering forces the films to be an integral number of smectic layers thick, quantizing their thickness in layer units and forcing a film of a particular number of layers to be physically homogeneous with respect to its layer structure over its entire area. Optical reflectivity enables the precise determination of the number of layers. These ultrathin freely suspended liquid crystal films are structures of fundamental interest in condensed matter and fluid physics. They are the thinnest known stable fluid structures and have the largest surface-to-volume ratio of any stable fluid preparation, making them ideal for the study of the effects of reduced dimensionality on phase behavior and on fluctuation and interface phenomena. Their low vapor pressure and quantized thickness enable the effective use of microgravity to extend the study of basic capillary phenomena to ultrathin fluid films. Freely suspended films have been a wellspring of new LC physics. They have been used to provide unique experimental conditions for the study of condensed phase transitions in two dimensions. They are the only system in which the hexatic has been unambiguously identified as a phase of matter, and the only physical system in which fluctuations of a 2D XY system and Kosterlitz Thouless phase transition has been observed and 2D XY quasi long range order verified. Smectic films have enabled the precise determination of smectic layer electron density and positional fluctuation profiles and have been used to show that the interlayer interactions in antiferroelectric tilted smectics do not extend significantly beyond nearest neighbors. Freely suspended films played a pivotal role in the recent discovery of macroscopic chiral-polar ordering in fluids of achiral molecules. The interactions which are operative in liquid crystals are generally weak in comparison to those in crystalline phases, leading to the facile manipulation of the order in liquid crystals by external agents such as applied fields and surfaces. Effects arising from weak ordering are significantly enhanced in ultrathin free films and filaments, in which the intermolecular coupling is effectively further reduced by loss of neighbors. Over the past four years this research, which we now detail, has produced a host of exciting new discoveries and unexpected results, maintaining the study of freely suspended liquid crystal structures as one of most exciting and fruitful areas of complex fluid physics. In addition, a class of experiments on the behavior of 1D interfaces in 2D films have been pursued with results that point to potentially quite interesting effects in microgravity.

EFFECT OF Mg AND TEMPERATURE ON Fe-Al ALLOY LAYER IN Fe/(Zn-6%Al-x%Mg) SOLID-LIQUID DIFFUSION COUPLES

NASA Astrophysics Data System (ADS)

Liang, Liu; Liu, Ya-Ling; Liu, Ya; Peng, Hao-Ping; Wang, Jian-Hua; Su, Xu-Ping

Fe/(Zn-6%Al-x%Mg) solid-liquid diffusion couples were kept at various temperatures for different periods of time to investigate the formation and growth of the Fe-Al alloy layer. Scanning electron microscopy (SEM), energy dispersive spectrometry (EDS) and X-ray diffraction (XRD) were used to study the constituents and morphology of the Fe-Al alloy layer. It was found that the Fe2Al5Znx phase layer forms close to the iron sheet and the FeAl3Znx phase layer forms near the side of the melted Zn-6%Al-3%Mg in diffusion couples. When the Fe/(Zn-6%Al-3%Mg) diffusion couple is kept at 510∘C for more than 15min, a continuous Fe-Al alloy layer is formed on the interface of the diffusion couple. Among all Fe/(Zn-6%Al-x%Mg) solid-liquid diffusion couples, the Fe-Al alloy layer on the interface of the Fe/(Zn-6% Al-3% Mg) diffusion couple is the thinnest. The Fe-Al alloy layer forms only when the diffusion temperature is above 475∘. These results show that the Fe-Al alloy layer in Fe/(Zn-6%Al-x%Mg) solid-liquid diffusion couples is composed of Fe2Al5Znx and FeAl3Znx phase layers. Increasing the diffusing temperature and time period would promote the formation and growth of the Fe-Al alloy layer. When the Mg content in the Fe/(Zn-6%Al-x%Mg) diffusion couples is 3%, the growth of the Fe-Al alloy layer is inhibited. These results may explain why there is no obvious Fe-Al alloy layer formed on the interface of steel with a Zn-6%Al-3%Mg coating.

Flash evaporation of liquid monomer particle mixture

DOEpatents

Affinito, J.D.; Darab, J.G.; Gross, M.E.

1999-05-11

The present invention is a method of making a first solid composite polymer layer. The method has the steps of (a) mixing a liquid monomer with particles substantially insoluble in the liquid monomer forming a monomer particle mixture; (b) flash evaporating the particle mixture and forming a composite vapor; and (c) continuously cryocondensing said composite vapor on a cool substrate and cross-linking the cryocondensed film thereby forming the polymer layer. 3 figs.

Mathematical Modeling and Optimization Studies on Development of Fuel Cells for Multifarious Applications

DTIC Science & Technology

2010-05-12

multicomponent steady-state model for liquid -feed solid polymer electrolyte DBFCs. These fuel cells use sodium borohydride (NaBH4) in alkaline media...layers, diffusion layers and the polymer electrolyte membrane for a liquid feed DBFC. Diffusion of reactants within and between the pores is accounted...projected for futuristic portable applications. In this project we developed a three- dimensional, multicomponent steady-state model for liquid -feed solid

Hydrodynamic water impact. [Apollo spacecraft waterlanding

NASA Technical Reports Server (NTRS)

Kettleborough, C. F.

1972-01-01

The hydrodynamic impact of a falling body upon a viscous incompressible fluid was investigated by numerically solving the equations of motion. Initially the mathematical model simulated the axisymmetric impact of a rigid right circular cylinder upon the initially quiescent free surface of a fluid. A compressible air layer exists between the falling cylinder and the liquid free surface. The mathematical model was developed by applying the Navier-Stokes equations to the incompressible air layer and the incompressible fluid. Assuming the flow to be one dimensional within the air layer, the average velocity, pressure and density distributions were calculated. The liquid free surface was allowed to deform as the air pressure acting on it increases. For the liquid the normalized equations were expressed in two-dimensional cylindrical coordinates. The governing equations for the air layer and the liquid were expressed in finite difference form and solved numerically. For the liquid a modified version of the Marker-and-Cell method was used. The mathematical model has been reexamined and a new approach has recently been initiated. Essentially this consists of examining the impact of an inclined plate onto a quiesent water surface with the equations now formulated in cartesian coordinates.

Organic light emitting device having multiple separate emissive layers

DOEpatents

Forrest, Stephen R [Ann Arbor, MI

2012-03-27

An organic light emitting device having multiple separate emissive layers is provided. Each emissive layer may define an exciton formation region, allowing exciton formation to occur across the entire emissive region. By aligning the energy levels of each emissive layer with the adjacent emissive layers, exciton formation in each layer may be improved. Devices incorporating multiple emissive layers with multiple exciton formation regions may exhibit improved performance, including internal quantum efficiencies of up to 100%.

Ionic liquids behave as dilute electrolyte solutions

PubMed Central

Gebbie, Matthew A.; Valtiner, Markus; Banquy, Xavier; Fox, Eric T.; Henderson, Wesley A.; Israelachvili, Jacob N.

2013-01-01

We combine direct surface force measurements with thermodynamic arguments to demonstrate that pure ionic liquids are expected to behave as dilute weak electrolyte solutions, with typical effective dissociated ion concentrations of less than 0.1% at room temperature. We performed equilibrium force–distance measurements across the common ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([C4mim][NTf2]) using a surface forces apparatus with in situ electrochemical control and quantitatively modeled these measurements using the van der Waals and electrostatic double-layer forces of the Derjaguin–Landau–Verwey–Overbeek theory with an additive repulsive steric (entropic) ion–surface binding force. Our results indicate that ionic liquids screen charged surfaces through the formation of both bound (Stern) and diffuse electric double layers, where the diffuse double layer is comprised of effectively dissociated ionic liquid ions. Additionally, we used the energetics of thermally dissociating ions in a dielectric medium to quantitatively predict the equilibrium for the effective dissociation reaction of [C4mim][NTf2] ions, in excellent agreement with the measured Debye length. Our results clearly demonstrate that, outside of the bound double layer, most of the ions in [C4mim][NTf2] are not effectively dissociated and thus do not contribute to electrostatic screening. We also provide a general, molecular-scale framework for designing ionic liquids with significantly increased dissociated charge densities via judiciously balancing ion pair interactions with bulk dielectric properties. Our results clear up several inconsistencies that have hampered scientific progress in this important area and guide the rational design of unique, high–free-ion density ionic liquids and ionic liquid blends. PMID:23716690

INTERNATIONAL CONFERENCE ON SEMICONDUCTOR INJECTION LASERS SELCO-87: High-performance 1.3-μm InGaAsP/InP heterostructures formed by two-phase liquid epitaxy

NASA Astrophysics Data System (ADS)

Novotný, J.; Procházková, O.; Šrobár, F.; Zelinka, J.

1988-11-01

A description is given of a two-phase liquid epitaxy method used to grow InGaAsP/InP heterostructures intended for injection lasers emitting in the 1.3-μm range. A study was made of heterostructures of three types: double, with an additional quaternary layer (λ approx 1.1 μm) adjoining the active layer; with two quaternary layers between the active layer and the InP confining layers. The configuration with two flanking quaternary layers was found to be the best from the point of view of the threshold current density, optical output power, and reproducibility.

Theory of a quantum spin liquid in the hydrogen-intercalated honeycomb iridate H3LiIr2O6

NASA Astrophysics Data System (ADS)

Slagle, Kevin; Choi, Wonjune; Chern, Li Ern; Kim, Yong Baek

2018-03-01

We propose a theoretical model for a gapless spin liquid phase that may have been observed in a recent experiment on H3LiIr2O6 . Despite the insulating and nonmagnetic nature of the material, the specific heat coefficient C /T ˜1 /√{T } in zero magnetic field and C /T ˜T /B3 /2 with finite magnetic field B have been observed. In addition, the NMR relaxation rate shows 1 /(T1T ) ˜(C/T ) 2 . Motivated by the fact that the interlayer/in-plane lattice parameters are reduced/elongated by the hydrogen intercalation of the parent compound Li2IrO3 , we consider four layers of the Kitaev honeycomb lattice model with additional interlayer exchange interactions. It is shown that the resulting spin liquid excitations reside mostly in the top and bottom layers of such a layered structure and possess a quartic dispersion. In an applied magnetic field, each quartic mode is split into four Majorana cones with the velocity v ˜B3 /4 . We suggest that the spin liquid phase in these "defect" layers, placed between different stacking patterns of the honeycomb layers, can explain the major phenomenology of the experiment, which can be taken as evidence that the Kitaev interaction plays the primary role in the formation of a quantum spin liquid in this material.

Determining the imaging plane of a retinal capillary layer in adaptive optical imaging

NASA Astrophysics Data System (ADS)

Yang, Le-Bao; Hu, Li-Fa; Li, Da-Yu; Cao, Zhao-Liang; Mu, Quan-Quan; Ma, Ji; Xuan, Li

2016-09-01

Even in the early stage, endocrine metabolism disease may lead to micro aneurysms in retinal capillaries whose diameters are less than 10 μm. However, the fundus cameras used in clinic diagnosis can only obtain images of vessels larger than 20 μm in diameter. The human retina is a thin and multiple layer tissue, and the layer of capillaries less than 10 μm in diameter only exists in the inner nuclear layer. The layer thickness of capillaries less than 10 μm in diameter is about 40 μm and the distance range to rod&cone cell surface is tens of micrometers, which varies from person to person. Therefore, determining reasonable capillary layer (CL) position in different human eyes is very difficult. In this paper, we propose a method to determine the position of retinal CL based on the rod&cone cell layer. The public positions of CL are recognized with 15 subjects from 40 to 59 years old, and the imaging planes of CL are calculated by the effective focal length of the human eye. High resolution retinal capillary imaging results obtained from 17 subjects with a liquid crystal adaptive optics system (LCAOS) validate our method. All of the subjects’ CLs have public positions from 127 μm to 147 μm from the rod&cone cell layer, which is influenced by the depth of focus. Project supported by the National Natural Science Foundation of China (Grant Nos. 11174274, 11174279, 61205021, 11204299, 61475152, and 61405194).

Fred's Flow (Canada) and Murphy Well (Australia): thick komatiitic lava flows with contrasting compositions, emplacement mechanisms and water contents

NASA Astrophysics Data System (ADS)

Siégel, C.; Arndt, N. T.; Henriot, A.-L.; Barnes, S. J.

2012-04-01

Two Archaean komatiitic flows, Fred's Flow in Canada and the Murphy Well flow in Australia, have similar thicknesses (120 m and 160 m) but very different compositions and internal structures. Fred's Flow is the type example of a thick komatiitic basaltic flow. It is strongly differentiated and consists of a succession of layers with contrasting textures and compositions. The layering is readily explained by the accumulation of olivine and pyroxene in a lower cumulate layer and by evolution of the liquid composition during downward growth of spinifex-textured rocks within the upper crust. A parental liquid was constrained to contain ca. 18 wt% MgO and ca. 5 to 35%vol phenocrysts and it differentiated into cumulates containing 45 wt% MgO and a residual gabbroic layer with only 6 wt% MgO. The Murphy Well flow, in contrast, has a remarkably uniform composition throughout. It comprises two layers, a 20-m-thick upper layer composed of fine-grained dendritic olivine and 2-10% amygdales, a 120-m-thick lower layer of olivine porphyry, and a lowermost 20 m of olivine orthocumulate. Throughout the flow, MgO contents vary little, from only 30 to 34 wt%, except for the slightly more magnesian basal layer (35-40 wt%). The uniform composition and dendritic olivine habits suggest rapid cooling of a highly magnesian liquid with a composition like that of the bulk of the flow. Under equilibrium conditions this liquid should have crystallized olivine with the composition Fo95.5 but the most magnesian composition measured by electron microprobe in samples from the flow is Fo93. To explain these features, we propose that the original liquid was hydrous and contained around 32% MgO. It degassed during eruption creating a supercooled liquid that solidified quickly and crystallized olivine with non-equilibrium compositions. To account for the 60-70vol% olivine throughout the flow requires a combination of degassing and cooling by the evacuation of heat in the escaping fluid.

Fate and transport of the ß-adrenergic agonist ractopamine hydrochloride in soil-water systems

USDA-ARS?s Scientific Manuscript database

The feed additive ractopamine hydrochloride was fortified at four concentrations into batch vials containing soils that differed in both biological activity and organic matter (OM). Sampling of the liquid layer for 14 d demonstrated that ractopamine rapidly dissipated from the liquid layer. Less t...

Liquid/liquid interface layering of 1-butanol and [bmim]PF6 ionic liquid: a nonlinear vibrational spectroscopy and molecular dynamics simulation study.

PubMed

Iwahashi, Takashi; Ishiyama, Tatsuya; Sakai, Yasunari; Morita, Akihiro; Kim, Doseok; Ouchi, Yukio

2015-10-14

IR-visible sum-frequency generation (IV-SFG) vibrational spectroscopy and a molecular dynamics (MD) simulation were used to study the local layering order at the interface of 1-butanol-d9 and 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF6), a room-temperature ionic liquid (RTIL). The presence of a local non-polar layer at the interface of the two polar liquids was successfully demonstrated. In the SFG spectra of 1-butanol-d9, we observed significant reduction and enhancement in the strength of the CD3 symmetric stretching (r(+)) mode and the antisymmetric stretching (r(-)) mode peaks, respectively. The results can be well explained by the presence of an oppositely oriented quasi-bilayer structure of butanol molecules, where the bottom layer is strongly bound by hydrogen-bonding with the PF6(-) anion. MD simulations reveal that the hydrogen-bonding of butanol with the PF6(-) anion causes the preferential orientation of the butanols; the restriction on the rotational distribution of the terminal methyl group along their C3 axis enhances the r(-) mode. As for the [bmim](+) cations, the SFG spectra taken within the CH stretch region indicate that the butyl chain of [bmim](+) points away from the bulk RTIL phase to the butanol phase at the interface. Combining the SFG spectroscopy and MD simulation results, we propose an interfacial model structure of layering, in which the butyl chains of the butanol molecules form a non-polar interfacial layer with the butyl chains of the [bmim](+) cations at the interface.

X-ray and Electrochemical Impedance Spectroscopy Diagnostic Investigations of Liquid Water in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers

NASA Astrophysics Data System (ADS)

Antonacci, Patrick

In this thesis, electrochemical impedance spectroscopy (EIS) and synchrotron x-ray radiography were utilized to characterize the impact of liquid water distributions in polymer electrolyte membrane fuel cell (PEMFC) gas diffusion layers (GDLs) on fuel cell performance. These diagnostic techniques were used to quantify the effects of liquid water visualized on equivalent resistances measured through EIS. The effects of varying the thickness of the microporous layer (MPL) of GDLs were studied using these diagnostic techniques. In a first study on the feasibility of this methodology, two fuel cell cases with a 100 microm-thick and a 150 microm-thick MPL were compared under constant current density operation. In a second study with 10, 30, 50, and 100 microm-thick MPLs, the liquid water in the cathode substrate was demonstrated to affect mass transport resistance, while the liquid water content in the anode (from back diffusion) affected membrane hydration, evidenced through ohmic resistance measurements.

ATLAS event display: Virtual Point-1 visualization software

NASA Astrophysics Data System (ADS)

Seeley, Kaelyn; Dimond, David; Bianchi, R. M.; Boudreau, Joseph; Hong, Tae Min; Atlas Collaboration

2017-01-01

Virtual Point-1 (VP1) is an event display visualization software for the ATLAS Experiment. VP1 is a software framework that makes use of ATHENA, the ATLAS software infrastructure, to access the complete detector geometry. This information is used to draw graphics representing the components of the detector at any scale. Two new features are added to VP1. The first is a traditional ``lego'' plot, displaying the calorimeter energy deposits in eta-phi space. The second is another lego plot focusing on the forward endcap region, displaying the energy deposits in r-phi space. Currently, these new additions display the energy deposits based on the granularity of the middle layer of the liquid-Argon electromagnetic calorimeter. Since VP1 accesses the complete detector geometry and all experimental data, future developments are outlined for a more detailed display involving multiple layers of the calorimeter along with their distinct granularities.

Development of an improved model for runback water on aircraft surfaces

NASA Technical Reports Server (NTRS)

Al-Khalil, Kamel M.; Keith, Theo G., Jr.; De Witt, Kenneth J.

1992-01-01

A computer simulation for 'running wet' and evaporative aircraft anti-icing systems is developed. The model is based on the analysis of the liquid water film which forms in the regions of direct impingement and, then, breaks up near the impingement limits into rivulets. The wetness factor distribution resulting from the film breakup and the rivulet configuration on the surface are predicted using a stability analysis theory and the laws of mass energy conservation. The solid structure is modeled as a multiple layer wall. The anti-icing system modeled is of the thermal type utilizing hot air and/or electrical heating elements embedded within the wall layers. Experimental observations revealing some of the basic physics of the water flow on the surface are presented. Detailed qualitative documentation of the tests are given. Several numerical examples are considered, and the effect of some of the involved parameters on the system performance are investigated.

Multi-Layer Arctic Mixed-Phase Clouds Simulated by a Cloud-Resolving Model: Comparison with ARM Observations and Sensitivity Experiments

NASA Technical Reports Server (NTRS)

Luo, Yali; Xu, Kuan-Man; Morrison, Hugh; McFarquhar, Greg M.; Wang, Zhien; Zhang, Gong

2007-01-01

A cloud-resolving model (CRM) is used to simulate the multiple-layer mixed-phase stratiform (MPS) clouds that occurred during a three-and-a-half day subperiod of the Department of Energy-Atmospheric Radiation Measurement Program s Mixed-Phase Arctic Cloud Experiment (M-PACE). The CRM is implemented with an advanced two-moment microphysics scheme, a state-of-the-art radiative transfer scheme, and a complicated third-order turbulence closure. Concurrent meteorological, aerosol, and ice nucleus measurements are used to initialize the CRM. The CRM is prescribed by time-varying large-scale advective tendencies of temperature and moisture and surface turbulent fluxes of sensible and latent heat. The CRM reproduces the occurrences of the single- and double-layer MPS clouds as revealed by the M-PACE observations. However, the simulated first cloud layer is lower and the second cloud layer thicker compared to observations. The magnitude of the simulated liquid water path agrees with that observed, but its temporal variation is more pronounced than that observed. As in an earlier study of single-layer cloud, the CRM also captures the major characteristics in the vertical distributions and temporal variations of liquid water content (LWC), total ice water content (IWC), droplet number concentration and ice crystal number concentration (nis) as suggested by the aircraft observations. However, the simulated mean values differ significantly from the observed. The magnitude of nis is especially underestimated by one order of magnitude. Sensitivity experiments suggest that the lower cloud layer is closely related to the surface fluxes of sensible and latent heat; the upper cloud layer is probably initialized by the large-scale advective cooling/moistening and maintained through the strong longwave (LW) radiative cooling near the cloud top which enhances the dynamical circulation; artificially turning off all ice-phase microphysical processes results in an increase in LWP by a factor of 3 due to interactions between the excessive LW radiative cooling and extra cloud water; heating caused by phase change of hydrometeors could affect the LWC and cloud top height by partially canceling out the LW radiative cooling. It is further shown that the resolved dynamical circulation appears to contribute more greatly to the evolution of the MPS cloud layers than the parameterized subgrid-scale circulation.

Theoretical and experimental studies of hyperreflective polymer-network cholesteric liquid crystal structures with helicity inversion

NASA Astrophysics Data System (ADS)

Tasolamprou, A. C.; Mitov, M.; Zografopoulos, D. C.; Kriezis, E. E.

2009-03-01

Single-layer cholesteric liquid crystals exhibit a reflection coefficient which is at most 50% for unpolarized incident light. We give theoretical and experimental evidence of single-layer polymer-stabilized cholesteric liquid-crystalline structures that demonstrate hyper-reflective properties. Such original features are derived by the concurrent and randomly interlaced presence of both helicities. The fundamental properties of such structures are revealed by detailed numerical simulations based on a stochastic approach.

Water Transport in the Micro Porous Layer and Gas Diffusion Layer of a Polymer Electrolyte Fuel Cell

NASA Astrophysics Data System (ADS)

Qin, C.; Hassanizadeh, S. M.

2015-12-01

In this work, a recently developed dynamic pore-network model is presented [1]. The model explicitly solves for both water pressure and capillary pressure. A semi-implicit scheme is used in updating water saturation in each pore body, which considerably increases the numerical stability at low capillary number values. Furthermore, a multiple-time-step algorithm is introduced to reduce the computational effort. A number of case studies of water transport in the micro porous layer (MPL) and gas diffusion layer (GDL) are conducted. We illustrate the role of MPL in reducing water flooding in the GDL. Also, the dynamic water transport through the MPL-GDL interface is explored in detail. This information is essential to the reduced continua model (RCM), which was developed for multiphase flow through thin porous layers [2, 3]. C.Z. Qin, Water transport in the gas diffusion layer of a polymer electrolyte fuel cell: dynamic pore-network modeling, J Electrochimical. Soci., 162, F1036-F1046, 2015. C.Z. Qin and S.M. Hassanizadeh, Multiphase flow through multilayers of thin porous media: general balance equations and constitutive relationships for a solid-gas-liquid three-phase system, Int. J. Heat Mass Transfer, 70, 693-708, 2014. C.Z. Qin and S.M. Hassanizadeh, A new approach to modeling water flooding in a polymer electrolyte fuel cell, Int. J. Hydrogen Energy, 40, 3348-3358, 2015.

On the structure of cellular solutions in Rayleigh-Benard-Marangoni flows in small-aspect-ratio containers

NASA Technical Reports Server (NTRS)

Dijkstra, Henk A.

1992-01-01

Multiple steady flow patterns occur in surface-tension/buoyancy-driven convection in a liquid layer heated from below (Rayleigh-Benard-Marangoni flows). Techniques of numerical bifurcation theory are used to study the multiplicity and stability of two-dimensional steady flow patterns (rolls) in rectangular small-aspect-ratio containers as the aspect ratio is varied. For pure Marangoni flows at moderate Biot and Prandtl number, the transitions occurring when paths of codimension 1 singularities intersect determine to a large extent the multiplicity of stable patterns. These transitions also lead, for example, to Hopf bifurcations and stable periodic flows for a small range in aspect ratio. The influence of the type of lateral walls on the multiplicity of steady states is considered. 'No-slip' lateral walls lead to hysteresis effects and typically restrict the number of stable flow patterns (with respect to 'slippery' sidewalls) through the occurrence of saddle node bifurcations. In this way 'no-slip' sidewalls induce a selection of certain patterns, which typically have the largest Nusselt number, through secondary bifurcation.

Thermal Rayleigh-Marangoni convection in a three-layer liquid-metal-battery model.

PubMed

Köllner, Thomas; Boeck, Thomas; Schumacher, Jörg

2017-05-01

The combined effects of buoyancy-driven Rayleigh-Bénard convection (RC) and surface tension-driven Marangoni convection (MC) are studied in a triple-layer configuration which serves as a simplified model for a liquid metal battery (LMB). The three-layer model consists of a liquid metal alloy cathode, a molten salt separation layer, and a liquid metal anode at the top. Convection is triggered by the temperature gradient between the hot electrolyte and the colder electrodes, which is a consequence of the release of resistive heat during operation. We present a linear stability analysis of the state of pure thermal conduction in combination with three-dimensional direct numerical simulations of the nonlinear turbulent evolution on the basis of a pseudospectral method. Five different modes of convection are identified in the configuration, which are partly coupled to each other: RC in the upper electrode, RC with internal heating in the molten salt layer, and MC at both interfaces between molten salt and electrode as well as anticonvection in the middle layer and lower electrode. The linear stability analysis confirms that the additional Marangoni effect in the present setup increases the growth rates of the linearly unstable modes, i.e., Marangoni and Rayleigh-Bénard instability act together in the molten salt layer. The critical Grashof and Marangoni numbers decrease with increasing middle layer thickness. The calculated thresholds for the onset of convection are found for realistic current densities of laboratory-sized LMBs. The global turbulent heat transfer follows scaling predictions for internally heated RC. The global turbulent momentum transfer is comparable with turbulent convection in the classical Rayleigh-Bénard case. In summary, our studies show that incorporating Marangoni effects generates smaller flow structures, alters the velocity magnitudes, and enhances the turbulent heat transfer across the triple-layer configuration.

Thermal Rayleigh-Marangoni convection in a three-layer liquid-metal-battery model

NASA Astrophysics Data System (ADS)

Köllner, Thomas; Boeck, Thomas; Schumacher, Jörg

2017-05-01

The combined effects of buoyancy-driven Rayleigh-Bénard convection (RC) and surface tension-driven Marangoni convection (MC) are studied in a triple-layer configuration which serves as a simplified model for a liquid metal battery (LMB). The three-layer model consists of a liquid metal alloy cathode, a molten salt separation layer, and a liquid metal anode at the top. Convection is triggered by the temperature gradient between the hot electrolyte and the colder electrodes, which is a consequence of the release of resistive heat during operation. We present a linear stability analysis of the state of pure thermal conduction in combination with three-dimensional direct numerical simulations of the nonlinear turbulent evolution on the basis of a pseudospectral method. Five different modes of convection are identified in the configuration, which are partly coupled to each other: RC in the upper electrode, RC with internal heating in the molten salt layer, and MC at both interfaces between molten salt and electrode as well as anticonvection in the middle layer and lower electrode. The linear stability analysis confirms that the additional Marangoni effect in the present setup increases the growth rates of the linearly unstable modes, i.e., Marangoni and Rayleigh-Bénard instability act together in the molten salt layer. The critical Grashof and Marangoni numbers decrease with increasing middle layer thickness. The calculated thresholds for the onset of convection are found for realistic current densities of laboratory-sized LMBs. The global turbulent heat transfer follows scaling predictions for internally heated RC. The global turbulent momentum transfer is comparable with turbulent convection in the classical Rayleigh-Bénard case. In summary, our studies show that incorporating Marangoni effects generates smaller flow structures, alters the velocity magnitudes, and enhances the turbulent heat transfer across the triple-layer configuration.

Layering of inertial confinement fusion targets in microgravity environments

NASA Astrophysics Data System (ADS)

Parks, P. B.; Fagaly, R. L.

1995-02-01

A critical concern in the fabrication of targets for inertial confinement fusion is ensuring that the hydrogenic (D2 or DT) fuel layer maintains spherical symmetry. Because of gravitationally induced sagging of the liquid prior to freezing, only relatively thin (less than 10 micrometers) layers of solid fuel can be produced by fast refreeze methods. One method to reduce the effective gravitational field environment is free-fall insertion into the target chamber. Another method to counterbalance the gravitational force is to use an applied magnetic field combined with a gradient field to induce a magnetic dipole force (F(sub m)) on the liquid fuel layer. For liquid deuterium, the required B dot product del(vector differential operator) B product to counterbalance the gravitational force (F(sub g)) is approximately 10 T(exp 2)/cm. In this paper, we examine the time-dependent dynamics of the liquid fuel layer in a reduced gravitational field environment. We employ an energy method which takes into account the sum of the free energy associated with the surface tension forces, net vertical force (F = F(sub m) - F(sub g) (in the case of magnetic field-assisted microgravity) or F(sub D) (the drag force in the case of free fall)), London-van der Waals forces, the kinetic energy of motion and viscous dissipation. By assuming that the motions are incompressible and irrotational, the volume integrals of the free energies over the deformed liquid fuel layer may be converted to surface integrals. With the surface expressed as the sum of Legendre polynomials, r(sub surface) = a + Sigma a(sub l)(t)P(sub l)(mu), the perturbed amplitude of the individual modes, a(sub l)(t) can be obtained. We show that the l = 1 vertical shift mode takes the longest to damp out, and may be problematic for free-fall insertion even for thin approximately 1 micrometer overfilled foam targets. For a given liquid fuel layer thickness delta, the equilibrium value of a(sub 1)/a (the concentricity of the inner fuel layer) is shown to be dependent on the net vertical force F and layer thickness, i.e., a(sub 1) approximately F delta(exp 5), but independent of the surface tension.

Two-phase convection in the high-pressure ice layer of the large icy moons: geodynamical implications

NASA Astrophysics Data System (ADS)

Kalousova, K.; Sotin, C.; Tobie, G.; Choblet, G.; Grasset, O.

2015-12-01

The H2O layers of large icy satellites such as Ganymede, Callisto, or Titan probably include a liquid water ocean sandwiched between the deep high-pressure ice layer and the outer ice I shell [1]. It has been recently suggested that the high-pressure ice layer could be decoupled from the silicate core by a salty liquid water layer [2]. However, it is not clear whether accumulation of liquids at the bottom of the high-pressure layer is possible due to positive buoyancy of water with respect to high-pressure ice. Numerical simulation of this two-phase (i.e. ice and water) problem is challenging, which explains why very few studies have self-consistently handled the presence and transport of liquids within the solid ice [e.g. 3]. While using a simplified description of water production and transport, it was recently showed in [4] that (i) a significant fraction of the high-pressure layer reaches the melting point and (ii) the melt generation and its extraction to the overlying ocean significantly influence the global thermal evolution and interior structure of the large icy moons.Here, we treat the high-pressure ice layer as a compressible mixture of solid ice and liquid water [5]. Several aspects are investigated: (i) the effect of the water formation on the vigor of solid-state convection and its influence on the amount of heat that is transferred from the silicate mantle to the ocean; (ii) the fate of liquids within the upper thermal boundary layer - whether they freeze or reach the ocean; and (iii) the effect of salts and volatile compounds (potentially released from the rocky core) on the melting/freezing processes. Investigation of these aspects will allow us to address the thermo-chemical evolution of the internal ocean which is crucial to evaluate the astrobiological potential of large icy moons. This work has been performed at the Jet Propulsion Laboratory, California Institute of Technology, under contract to NASA. [1] Hussmann et al. (2007), Treatise of Geophysics, 10.15, 509-539. [2] Vance et al. (2014), Planet. Space Sci., 96, 62-70. [3] Kalousova et al. (2014), J. Geophys. Res. Planets, 119(3), 532-549. [4] Tobie et al. (2014), AGU, P43C-3999. [5] Soucek et al. (2014), Geophys. Astro. Fluid, 108(6), 639-666.

Sloshing instability and electrolyte layer rupture in liquid metal batteries

NASA Astrophysics Data System (ADS)

Weber, Norbert; Beckstein, Pascal; Herreman, Wietze; Horstmann, Gerrit Maik; Nore, Caroline; Stefani, Frank; Weier, Tom

2017-05-01

Liquid metal batteries (LMBs) are discussed today as a cheap grid scale energy storage, as required for the deployment of fluctuating renewable energies. Built as stable density stratification of two liquid metals separated by a thin molten salt layer, LMBs are susceptible to short-circuit by fluid flows. Using direct numerical simulation, we study a sloshing long wave interface instability in cylindrical cells, which is already known from aluminium reduction cells. After characterising the instability mechanism, we investigate the influence of cell current, layer thickness, density, viscosity, conductivity and magnetic background field. Finally we study the shape of the interface and give a dimensionless parameter for the onset of sloshing as well as for the short-circuit.

Thermal Evolution of The Moon With a Thicker Kreep Layer

NASA Astrophysics Data System (ADS)

Hess, P. C.; Parmentier, E. M.

1998-01-01

The canonical view of the magma ocean is of a monotonically cooling large magma body perhaps enveloping the entire Moon, which solidified within about 100 my of the formation of the Moon. This model is consistent with W-Hf Sm-Nd isotope data, the very old ages of FAN and some magnesian-suite norites and troctolites and the model ages for KREEP. Recently, Korotev and Wieczorek and Phillips have argued that the crystallization of the last dregs of the magma ocean was not only prolonged but large amounts of radiogenic heating resulted in the remelting and dissolution of mafic cumulates by the UrKREEP liquid. These melts are believed to be parent liquids to the magnesian-suite troctolites because they account for the combination of high contents of incompatible trace elements and the very refractory major element composition. This model requires that the heat budget changes from one that cools the magma ocean to one that initiates reheating. About the only way to reverse this cooling trend is to segregate the magma ocean under some portions of the crust. For example, if the residual liquids are locally doubled in thickness the surface cooling is reduced thus reversing the cooling tend. By mass balance some portions of the magma ocean would be thinned and thereby would experience an accelerated cooling.accelerated cooling. We have examined the thermal history of the upper Moon. We formulate models of radioactive heating and conductive cooling to examine the possible role of a thick KREEP-rich layer on lunar regional thermal evolution. The models treat heat transfer by conduction in a spherical geometry with a KREEP layer containing a prescribed rate of radiogenic heating. The region of thick KREEP presumably exists only within the Imbrium-Procellarum region of the Moon. The spherical model is a reasonable representation of this case since the lateral dimensions of the region are large compared to its depth. The edges of the thick KREEP region which are not treated explicitly in this model will be small compared to the size of the region- As a basis for discussion we consider a 10km thick KREEP layer at the bottom of a 50km thick crust. The crust is capped with a 3km thick brecciated regolith layer in which the conductivity is reduced by a factor of ten. Within the layer we examine heating rates that are multiples of the rate radiogenic heating due to chondritic abundances of U and Th.

Method of forming a multiple layer dielectric and a hot film sensor therewith

NASA Technical Reports Server (NTRS)

Hopson, Purnell, Jr. (Inventor); Tran, Sang Q. (Inventor)

1990-01-01

The invention is a method of forming a multiple layer dielectric for use in a hot-film laminar separation sensor. The multiple layer dielectric substrate is formed by depositing a first layer of a thermoelastic polymer such as on an electrically conductive substrate such as the metal surface of a model to be tested under cryogenic conditions and high Reynolds numbers. Next, a second dielectric layer of fused silica is formed on the first dielectric layer of thermoplastic polymer. A resistive metal film is deposited on selected areas of the multiple layer dielectric substrate to form one or more hot-film sensor elements to which aluminum electrical circuits deposited upon the multiple layered dielectric substrate are connected.

Utilization of Additive Manufacturing for Aerospace Heat Exchangers

DTIC Science & Technology

2016-02-29

is made up of flat plates that are layered on top of each other creating air passages in between the plates where the hot liquid and cold liquid flow...electron beam- based) for two-dimensional scanning of the heat source on the powder layer , stages that decrease the build plate and increase the powder...build plate and result in uneven coating of subsequent powder layers or complete failure of the system to recoat. The perturbations in recoater

First Liquid Layer Inertial Confinement Fusion Implosions at the National Ignition Facility

DOE PAGES

Olson, R. E.; Leeper, R. J.; Kline, J. L.; ...

2016-12-07

The first cryogenic deuterium and deuterium-tritium liquid layer implosions at the National Ignition Facility (NIF) demonstrate D 2 and DT layer Inertial Confinement Fusion (ICF) implosions that can access low-to-moderate hot spot convergence ratio (1230) DT ice layer implosions. Although high CR is desirable in an idealized 1D sense, it amplifies the deleterious effects of asymmetries. To date, these asymmetries prevented the achievement of ignition at the NIF and are the major cause of simulation-experiment disagreement. In the initial liquid layer experiments, high neutron yields were achieved with CR’s of 12-17, and the hot spot formation is well understood, demonstratedmore » by good agreement between the experimental data and the radiation hydrodynamic simulations. These initial experiments open a new NIF experimental capability that provides an opportunity to explore the relationship between hot-spot convergence ratio and the robustness of hot-spot formation during ICF implosions.« less

First Liquid Layer Inertial Confinement Fusion Implosions at the National Ignition Facility

NASA Astrophysics Data System (ADS)

Olson, R. E.; Leeper, R. J.; Kline, J. L.; Zylstra, A. B.; Yi, S. A.; Biener, J.; Braun, T.; Kozioziemski, B. J.; Sater, J. D.; Bradley, P. A.; Peterson, R. R.; Haines, B. M.; Yin, L.; Berzak Hopkins, L. F.; Meezan, N. B.; Walters, C.; Biener, M. M.; Kong, C.; Crippen, J. W.; Kyrala, G. A.; Shah, R. C.; Herrmann, H. W.; Wilson, D. C.; Hamza, A. V.; Nikroo, A.; Batha, S. H.

2016-12-01

The first cryogenic deuterium and deuterium-tritium liquid layer implosions at the National Ignition Facility (NIF) demonstrate D2 and DT layer inertial confinement fusion (ICF) implosions that can access a low-to-moderate hot-spot convergence ratio (12 30 ) DT ice layer implosions. Although high CR is desirable in an idealized 1D sense, it amplifies the deleterious effects of asymmetries. To date, these asymmetries prevented the achievement of ignition at the NIF and are the major cause of simulation-experiment disagreement. In the initial liquid layer experiments, high neutron yields were achieved with CRs of 12-17, and the hot-spot formation is well understood, demonstrated by a good agreement between the experimental data and the radiation hydrodynamic simulations. These initial experiments open a new NIF experimental capability that provides an opportunity to explore the relationship between hot-spot convergence ratio and the robustness of hot-spot formation during ICF implosions.

First Liquid Layer Inertial Confinement Fusion Implosions at the National Ignition Facility.

PubMed

Olson, R E; Leeper, R J; Kline, J L; Zylstra, A B; Yi, S A; Biener, J; Braun, T; Kozioziemski, B J; Sater, J D; Bradley, P A; Peterson, R R; Haines, B M; Yin, L; Berzak Hopkins, L F; Meezan, N B; Walters, C; Biener, M M; Kong, C; Crippen, J W; Kyrala, G A; Shah, R C; Herrmann, H W; Wilson, D C; Hamza, A V; Nikroo, A; Batha, S H

2016-12-09

The first cryogenic deuterium and deuterium-tritium liquid layer implosions at the National Ignition Facility (NIF) demonstrate D_{2} and DT layer inertial confinement fusion (ICF) implosions that can access a low-to-moderate hot-spot convergence ratio (1230) DT ice layer implosions. Although high CR is desirable in an idealized 1D sense, it amplifies the deleterious effects of asymmetries. To date, these asymmetries prevented the achievement of ignition at the NIF and are the major cause of simulation-experiment disagreement. In the initial liquid layer experiments, high neutron yields were achieved with CRs of 12-17, and the hot-spot formation is well understood, demonstrated by a good agreement between the experimental data and the radiation hydrodynamic simulations. These initial experiments open a new NIF experimental capability that provides an opportunity to explore the relationship between hot-spot convergence ratio and the robustness of hot-spot formation during ICF implosions.

Active liquid-crystal deflector and lens with Fresnel structure

NASA Astrophysics Data System (ADS)

Shibuya, Giichi; Yamano, Shohei; Yoshida, Hiroyuki; Ozaki, Masanori

2017-02-01

A new type of tunable Fresnel deflector and lens composed of liquid crystal was developed. Combined structure of multiple interdigitated electrodes and the high-resistivity (HR) layer implements the saw-tooth distribution of electrical potential with only the planar surfaces of the transparent substrates. According to the numerical calculation and design, experimental devices were manufactured with the liquid crystal (LC) material sealed into the sandwiched flat glass plates of 0.7 mm thickness with rubbed alignment layers set to an anti-parallel configuration. Fabricated beam deflector with no moving parts shows the maximum tilt angle of +/-1.3 deg which can apply for optical image stabilizer (OIS) of micro camera. We also discussed and verified their lens characteristics to be extended more advanced applications. Transparent interdigitated electrodes were concentrically aligned on the lens aperture with the insulator gaps under their boundary area. The diameter of the lens aperture was 30 mm and the total number of Fresnel zone was 100. Phase retardation of the beam wavefront irradiated from the LC lens device can be evaluated by polarizing microscope images with a monochromatic filter. Radial positions of each observed fringe are plotted and fitted with 2nd degree polynomial approximation. The number of appeared fringes is over 600 in whole lens aperture area and the correlation coefficients of all approximations are over 0.993 that seems enough ideal optical wavefront. The obtained maximum lens powers from the approximations are about +/-4 m-1 which was satisfied both convex and concave lens characteristics; and their practical use for the tunable lens grade eyeglasses became more prospective.

Dynamic d-symmetry Bose condensate of a planar-large-bipolaron liquid in cuprate superconductors

NASA Astrophysics Data System (ADS)

Emin, David

2017-11-01

Planar-large-bipolarons can form if the ratio of the surrounding mediums' static to high-frequency dielectric constants is especially large, ε0/ε∞ >> 2. A large-bipolaron in p-doped La2CuO4 is modelled as two electrons being removed from the out-of-plane orbitals of four oxygen ions circumscribed by four copper ions of a CuO2 layer. These oxygen dianions relax inwardly as they donate electrons to the surrounding outwardly relaxing copper cations. This charge transfer generates the strong in-plane electron-lattice interaction needed to stabilise a large-bipolaron with respect to decomposing into polarons. The lowest-energy radial in-plane optic vibration of a large-bipolaron's four core oxygen ions with their associated electronic charges has d-symmetry. Electronic relaxation in response to multiple large-bipolarons' atomic vibrations lowers their frequencies to generate a phonon-mediated attraction among them which fosters their condensation into a liquid. This liquid features distinctive transport and optical properties. A large-bipolaron liquid's superconductivity can result when it undergoes a Bose condensation yielding macroscopic occupation of its ground state. The synchronised vibrations of large-bipolarons' core-oxygen ions with their electronic charges generate this Bose condensate's dynamic global d-symmetry.

EXPRESS: Accurate Measurement of the Optical Constants n and k for a Series of 57 Inorganic and Organic Liquids for Optical Modeling and Detection

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myers, Tanya L.; Tonkyn, Russell G.; Danby, Tyler O.

For optical modeling and other purposes, we have created a library of 57 liquids for which we have measured the complex optical constants n and k. These liquids vary in their nature, ranging in properties including chemical structure, optical band strength, volatility and viscosity. By obtaining the optical constants one can in principle model most optical phenomena in media and at interfaces including reflection, refraction and dispersion. Based on the original methods of J.E. Bertie et al.1 [1Bert1], we have developed improved protocols using multiple path lengths to determine the optical constants n/k for dozens of liquids, including inorganic, organicmore » and organophosphorus compounds. Detailed descriptions of the measurement and data reduction protocols are discussed; agreement of the derived optical constant n and k values with literature values are presented. We also present results using the n/k values as applied to an optical modeling scenario whereby the derived data are presented and tested for models of 1 µm and 100 µm layers for DMMP (dimethyl methyl phosphonate) on both metal (aluminum) and dielectric (soda lime glass) substrates to show substantial differences between the reflected signal from highly reflective substrates and less-reflective substrates.« less

Ultrathin-skinned asymmetric membranes by immiscible solvents treatment

DOEpatents

Friesen, Dwayne T.; Babcock, Walter C.

1989-01-01

Improved semipermeable asymmetric fluid separation membranes useful in gas, vapor and liquid separations are disclosed. The membranes are prepared by substantially filling the pores of asymmetric cellulosic semipermeable membranes having a finely porous layer on one side thereof with a water immiscible organic liquid, followed by contacting the finely porous layer with water.

Ultrathin-skinned asymmetric membranes by immiscible solvents treatment

DOEpatents

Friesen, D.T.; Babcock, W.C.

1989-11-28

Improved semipermeable asymmetric fluid separation membranes useful in gas, vapor and liquid separations are disclosed. The membranes are prepared by substantially filling the pores of asymmetric cellulosic semipermeable membranes having a finely porous layer on one side thereof with a water immiscible organic liquid, followed by contacting the finely porous layer with water.

Bubble baths: just splashing around?

NASA Astrophysics Data System (ADS)

Robinson, Wesley; Speirs, Nathan; Sharker, Saberul Islam; Hurd, Randy; Williams, Bj; Truscott, Tadd

2016-11-01

Soap Bubbles on the water surface would seem to be an intuitive means for splash suppression, but their presence appears to be a double edged sword. We present on the water entry of hydrophilic spheres where the liquid surface is augmented by the presence of a bubble layer, similar to a bubble bath. While the presence of a bubble layer can diminish splashing upon impact at low Weber numbers, it also induces cavity formation at speeds below the critical velocity. The formation of a cavity generally results in larger Worthington jets and thus, larger amounts of ejected liquid. Bubble layers induce cavity formation by wetting the sphere prior to liquid impact, causing them to form cavities similar to those created by hydrophobic spheres. Droplets present on a pre-wetted sphere disrupt the flow of the advancing liquid during entry, pushing it away from the impacting body to form an entrained air cavity. This phenomena was noted by Worthington with pre-wetted stone marbles, and suggests that the application of a bubble layer is generally ineffective as a means of splash suppression.

Effects of NAA and BAP, double-layered media, and light distance on in vitro regeneration of Nelumbo nucifera Gaertn. (lotus), an aquatic edible plant.

PubMed

Mahmad, Noraini; Taha, Rosna Mat; Othman, Rashidi; Saleh, Azani; Hasbullah, Nor Azlina; Elias, Hashimah

2014-01-01

In vitro direct regeneration of Nelumbo nucifera Gaertn. was successfully achieved from immature explants (yellow plumule) cultured on a solid MS media supplemented with combinations of 0.5 mg/L BAP and 1.5 mg/L NAA which resulted in 16.00 ± 0.30 number of shoots per explant and exhibited a new characteristic of layered multiple shoots, while normal roots formed on the solid MS basal media. The double-layered media gave the highest number of shoots per explant with a ratio of 2 : 1 (liquid to solid) with a mean number of 16.67 ± 0.23 shoots per explant with the formation of primary and secondary roots from immature explants. In the study involving light distance, the tallest shoot (16.67 ± 0.23 mm) obtained from the immature explants was at a light distance of 200 mm from the source of inflorescent light (1000 lux). The plantlets were successfully acclimatized in clay loam soil after 8 months being maintained under in vitro conditions.

An ab initio study of the structure and dynamics of bulk liquid Cd and its liquid-vapor interface.

PubMed

Calderín, L; González, L E; González, D J

2013-02-13

Several static and dynamic properties of bulk liquid Cd at a thermodynamic state near its triple point have been calculated by means of ab initio molecular dynamics simulations. The calculated static structure shows a very good agreement with the available experimental data. The dynamical structure reveals collective density excitations with an associated dispersion relation which points to a small positive dispersion. Results are also reported for several transport coefficients. Additional simulations have also been performed at a slightly higher temperature in order to study the structure of the free liquid surface. The ionic density profile shows an oscillatory behavior with two different wavelengths, as the spacing between the outer and first inner layer is different from that between the other inner layers. The calculated reflectivity shows a marked maximum whose origin is related to the surface layering, along with a shoulder located at a much smaller wavevector transfer.

First-order wetting transition at a liquid-vapor interface

NASA Technical Reports Server (NTRS)

Schmidt, J. W.; Moldover, M. R.

1983-01-01

Evidence from reflectance and contact angle measurements is presented that three-phase mixtures of i-C3H7OH-C7F14 exhibit a first-order wetting phase transition at the liquid-vapor interface at 38 C. Equilibration phenomena support this interpretation. Ellipsometry was used to measure the apparent thickness of the intruding layer in the three-phase mixture. At temperatures slightly above the wetting temperature T(w), the intruding layer's thickness is several hundred angstroms and its variation with temperature is extremely weak. Below T(w), three-phase contact can occur between the vapor and both the upper and lower liquid phases; one of the angles which characterizes this contact has a very simple temperature dependence. The thickness of the intruding layer, monitored as the solutions approached equilibrium, is found to depend quite weakly on the height spanned by the upper liquid phase in the vicinity of a first-order wetting transition.

Force microscopy of layering and friction in an ionic liquid

NASA Astrophysics Data System (ADS)

Hoth, Judith; Hausen, Florian; Müser, Martin H.; Bennewitz, Roland

2014-07-01

The mechanical properties of the ionic liquid 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl) trifluorophosphate ([Py1,4][FAP]) in confinement between a SiOx and a Au(1 1 1) surface are investigated by means of atomic force microscopy (AFM) under electrochemical control. Up to 12 layers of ion pairs can be detected through force measurements while approaching the tip of the AFM to the surface. The particular shape of the force versus distance curve is explained by a model for the interaction between tip, gold surface and ionic liquid, which assumes an exponentially decaying oscillatory force originating from bulk liquid density correlations. Jumps in the tip-sample distance upon approach correspond to jumps of the compliant force sensor between branches of the oscillatory force curve. Frictional force between the laterally moving tip and the surface is detected only after partial penetration of the last double layer between tip and surface.

Continuum-kinetic-microscopic model of lung clearance due to core-annular fluid entrainment

PubMed Central

Mitran, Sorin

2013-01-01

The human lung is protected against aspirated infectious and toxic agents by a thin liquid layer lining the interior of the airways. This airway surface liquid is a bilayer composed of a viscoelastic mucus layer supported by a fluid film known as the periciliary liquid. The viscoelastic behavior of the mucus layer is principally due to long-chain polymers known as mucins. The airway surface liquid is cleared from the lung by ciliary transport, surface tension gradients, and airflow shear forces. This work presents a multiscale model of the effect of airflow shear forces, as exerted by tidal breathing and cough, upon clearance. The composition of the mucus layer is complex and variable in time. To avoid the restrictions imposed by adopting a viscoelastic flow model of limited validity, a multiscale computational model is introduced in which the continuum-level properties of the airway surface liquid are determined by microscopic simulation of long-chain polymers. A bridge between microscopic and continuum levels is constructed through a kinetic-level probability density function describing polymer chain configurations. The overall multiscale framework is especially suited to biological problems due to the flexibility afforded in specifying microscopic constituents, and examining the effects of various constituents upon overall mucus transport at the continuum scale. PMID:23729842

Continuum-kinetic-microscopic model of lung clearance due to core-annular fluid entrainment

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mitran, Sorin, E-mail: mitran@unc.edu

2013-07-01

The human lung is protected against aspirated infectious and toxic agents by a thin liquid layer lining the interior of the airways. This airway surface liquid is a bilayer composed of a viscoelastic mucus layer supported by a fluid film known as the periciliary liquid. The viscoelastic behavior of the mucus layer is principally due to long-chain polymers known as mucins. The airway surface liquid is cleared from the lung by ciliary transport, surface tension gradients, and airflow shear forces. This work presents a multiscale model of the effect of airflow shear forces, as exerted by tidal breathing and cough,more » upon clearance. The composition of the mucus layer is complex and variable in time. To avoid the restrictions imposed by adopting a viscoelastic flow model of limited validity, a multiscale computational model is introduced in which the continuum-level properties of the airway surface liquid are determined by microscopic simulation of long-chain polymers. A bridge between microscopic and continuum levels is constructed through a kinetic-level probability density function describing polymer chain configurations. The overall multiscale framework is especially suited to biological problems due to the flexibility afforded in specifying microscopic constituents, and examining the effects of various constituents upon overall mucus transport at the continuum scale.« less

Continuum-kinetic-microscopic model of lung clearance due to core-annular fluid entrainment

NASA Astrophysics Data System (ADS)

Mitran, Sorin

2013-07-01

The human lung is protected against aspirated infectious and toxic agents by a thin liquid layer lining the interior of the airways. This airway surface liquid is a bilayer composed of a viscoelastic mucus layer supported by a fluid film known as the periciliary liquid. The viscoelastic behavior of the mucus layer is principally due to long-chain polymers known as mucins. The airway surface liquid is cleared from the lung by ciliary transport, surface tension gradients, and airflow shear forces. This work presents a multiscale model of the effect of airflow shear forces, as exerted by tidal breathing and cough, upon clearance. The composition of the mucus layer is complex and variable in time. To avoid the restrictions imposed by adopting a viscoelastic flow model of limited validity, a multiscale computational model is introduced in which the continuum-level properties of the airway surface liquid are determined by microscopic simulation of long-chain polymers. A bridge between microscopic and continuum levels is constructed through a kinetic-level probability density function describing polymer chain configurations. The overall multiscale framework is especially suited to biological problems due to the flexibility afforded in specifying microscopic constituents, and examining the effects of various constituents upon overall mucus transport at the continuum scale.

A study of deformation and strain induced in bulk by the oxide layers formation on a Fe-Cr-Al alloy in high-temperature liquid Pb-Bi eutectic

DOE PAGES

Popovic, M. P.; Chen, K.; Shen, H.; ...

2018-03-29

At elevated temperatures, heavy liquid metals and their alloys are known to create a highly corrosive environment that causes irreversible degradation of most iron-based materials. In this paper, it has been found that an appropriate concentration of oxygen in the liquid alloy can significantly reduce this issue by creating a passivating oxide scale that controls diffusion, especially if Al is present in Fe-based materials (by Al-oxide formation). However, the increase of the temperature and of oxygen content in liquid phase leads to the increase of oxygen diffusion into bulk, and to promotion of the internal Al oxidation. This can causemore » a strain in bulk near the oxide layer, due either to mismatch between the thermal expansion coefficients of the oxides and bulk material, or to misfit of the crystal lattices (bulk vs. oxides). This work investigates the strain induced into proximal bulk of a Fe-Cr-Al alloy by oxide layers formation in liquid lead-bismuth eutectic utilizing synchrotron X-ray Laue microdiffraction. Finally, it is found that internal oxidation is the most likely cause for the strain in the metal rather than thermal expansion mismatch as a two-layer problem.« less

A study of deformation and strain induced in bulk by the oxide layers formation on a Fe-Cr-Al alloy in high-temperature liquid Pb-Bi eutectic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Popovic, M. P.; Chen, K.; Shen, H.

At elevated temperatures, heavy liquid metals and their alloys are known to create a highly corrosive environment that causes irreversible degradation of most iron-based materials. In this paper, it has been found that an appropriate concentration of oxygen in the liquid alloy can significantly reduce this issue by creating a passivating oxide scale that controls diffusion, especially if Al is present in Fe-based materials (by Al-oxide formation). However, the increase of the temperature and of oxygen content in liquid phase leads to the increase of oxygen diffusion into bulk, and to promotion of the internal Al oxidation. This can causemore » a strain in bulk near the oxide layer, due either to mismatch between the thermal expansion coefficients of the oxides and bulk material, or to misfit of the crystal lattices (bulk vs. oxides). This work investigates the strain induced into proximal bulk of a Fe-Cr-Al alloy by oxide layers formation in liquid lead-bismuth eutectic utilizing synchrotron X-ray Laue microdiffraction. Finally, it is found that internal oxidation is the most likely cause for the strain in the metal rather than thermal expansion mismatch as a two-layer problem.« less

Microscopic properties of ionic liquid/organic semiconductor interfaces revealed by molecular dynamics simulations.

PubMed

Yokota, Yasuyuki; Miyamoto, Hiroo; Imanishi, Akihito; Takeya, Jun; Inagaki, Kouji; Morikawa, Yoshitada; Fukui, Ken-Ichi

2018-05-09

Electric double-layer transistors based on ionic liquid/organic semiconductor interfaces have been extensively studied during the past decade because of their high carrier densities at low operation voltages. Microscopic structures and the dynamics of ionic liquids likely determine the device performance; however, knowledge of these is limited by a lack of appropriate experimental tools. In this study, we investigated ionic liquid/organic semiconductor interfaces using molecular dynamics to reveal the microscopic properties of ionic liquids. The organic semiconductors include pentacene, rubrene, fullerene, and 7,7,8,8-tetracyanoquinodimethane (TCNQ). While ionic liquids close to the substrate always form the specific layered structures, the surface properties of organic semiconductors drastically alter the ionic dynamics. Ionic liquids at the fullerene interface behave as a two-dimensional ionic crystal because of the energy gain derived from the favorable electrostatic interaction on the corrugated periodic substrate.

Ultrasound liquid crystal lens

NASA Astrophysics Data System (ADS)

Shimizu, Yuki; Koyama, Daisuke; Fukui, Marina; Emoto, Akira; Nakamura, Kentaro; Matsukawa, Mami

2018-04-01

A variable-focus lens using a combination of liquid crystals and ultrasound is discussed. The lens uses a technique based on ultrasound vibration to control the molecular orientation of the liquid crystal. The lens structure is simple, with no mechanical moving parts and no transparent electrodes, which is helpful for device downsizing; the structure consists of a liquid crystal layer sandwiched between two glass substrates with a piezoelectric ring. The tens-of-kHz ultrasonic resonance flexural vibration used to excite the lens generates an acoustic radiation force on the liquid crystal layer to induce changes in the molecular orientation of the liquid crystal. The orientations of the liquid crystal molecules and the optical characteristics of the lens were investigated under ultrasound excitation. Clear optical images were observed through the lens, and the focal point could be controlled using the input voltage to the piezoelectric ring to give the lens its variable-focus action.

Liquid Marble Coalescence and Triggered Microreaction Driven by Acoustic Levitation.

PubMed

Chen, Zhen; Zang, Duyang; Zhao, Liang; Qu, Mengfei; Li, Xu; Li, Xiaoguang; Li, Lixin; Geng, Xingguo

2017-06-27

Liquid marbles show promising potential for application in the microreactor field. Control of the coalescence between two or among multiple liquid marbles is critical; however, the successful merging of two isolated marbles is difficult because of their mechanically robust particle shells. In this work, the coalescence of multiple liquid marbles was achieved via acoustic levitation. The dynamic behaviors of the liquid marbles were monitored by a high-speed camera. Driven by the sound field, the liquid marbles moved toward each other, collided, and eventually coalesced into a larger single marble. The underlying mechanisms of this process were probed via sound field simulation and acoustic radiation pressure calculation. The results indicated that the pressure gradient on the liquid marble surface favors the formation of a liquid bridge between the liquid marbles, resulting in their coalescence. A preliminary indicator reaction was induced by the coalescence of dual liquid marbles, which suggests that expected chemical reactions can be successfully triggered with multiple reagents contained in isolated liquid marbles via acoustic levitation.

Lu-Hf isotopic memory of plume-lithosphere interaction in the source of layered mafic intrusions, Windimurra Igneous Complex, Yilgarn Craton, Australia

NASA Astrophysics Data System (ADS)

Nebel, O.; Arculus, R. J.; Ivanic, T. J.; Nebel-Jacobsen, Y. J.

2013-10-01

Most layered mafic intrusions (LMI) are formed via multiple magma injections into crustal magma chambers. These magmas are originally sourced from the mantle, likely via plume activity, but may interact with the overriding lithosphere during ascent and emplacement in the crust. The magma injections lead to the establishment of different layers and zones with complex macroscopic, microscopic and cryptic compositional layering through magmatic differentiation and associated cumulate formation, sometimes accompanied by crustal assimilation. These complex mineralogical and petrological processes obscure the nature of the mantle sources of LMI, and typically have limited the degree to which parental liquids can be fully characterised. Here, we present Lu-Hf isotope data for samples from distinct layers of the Upper Zone of the Windimurra Igneous Complex (WIC), an immense late-Archean LMI in the West Australian Yilgarn Craton. Lu-Hf isotope systematics of whole rocks are well correlated (MSWD=5.6, n=17) with an age of ˜3.05±0.05 Ga and initial ɛHf˜+8. This age, however, is older than whole rock Sm-Nd and zircon U-Pb ages of the intrusion, both of which are ca. 2.8 Ga. Stratigraphically-controlled initial Hf isotope variations (associated with multiple episodes of emplacement at ca. 2.8 Ga) indicate isotope mixing between a near-chondritic and an ultra-radiogenic component, the latter with ɛHf[2.8 Ga]>+15. This Hf isotope mixing creates a pseudochron-relationship at the time of intrusion of ˜250 Myr that is superimposed on subsequent radiogenic ingrowth after crystallisation, generating an age that predates the actual emplacement event. Mixing between late-stage crystallisation products (melt + crystals) from the Middle Zone and replenishing, plume-derived liquids was followed by crystal accumulation in a chemically evolving magma chamber. The ultra-radiogenic Hf isotope endmember in the WIC mantle source requires parent-daughter ratios consistent with very early formation in Earth history, akin to early Archean komatiitic plume sources. We propose that plume-derived melts that formed the Windimurra LMI reacted with ancient refractory lithospheric keels already underpinning ancient cratons, creating a melt with extremely high ɛHf[t]. Melting a refractory component with super-chondritic, time-integrated high Lu/Hf, in this case by plume-lithosphere interaction, simultaneously accounts for the extreme Hf isotope signals, Hf-Nd isotope decoupling, and difference in radiometric Lu-Hf and Sm-Nd ages.

Numerical simulation of liquid-layer breakup on a moving wall due to an impinging jet

NASA Astrophysics Data System (ADS)

Yu, Taejong; Moon, Hojoon; You, Donghyun; Kim, Dokyun; Ovsyannikov, Andrey

2014-11-01

Jet wiping, which is a hydrodynamic method for controlling the liquid film thickness in coating processes, is constrained by a rather violent film instability called splashing. The instability is characterized by the ejection of droplets from the runback flow and results in an explosion of the film. The splashing phenomenon degrades the final coating quality. In the present research, a volume-of-fluid (VOF)-based method, which is developed at Cascade Technologies, is employed to simulate the air-liquid multiphase flow dynamics. The present numerical method is based on an unstructured-grid unsplit geometric VOF scheme and guarantees strict conservation of mass of two-phase flow, The simulation results are compared with experimental measurements such as the liquid-film thickness before and after the jet wiping, wall pressure and shear stress distributions. The trajectories of liquid droplets due to the fluid motion entrained by the gas-jet operation, are also qualitatively compared with experimental visualization. Physical phenomena observed during the liquid-layer breakup due to an impinging jet is characterized in order to develop ideas for controlling the liquid-layer instability and resulting splash generation and propagation. Supported by the Grant NRF-2012R1A1A2003699, the Brain Korea 21+ program, POSCO, and 2014 CTR Summer Program.

Investigation of surface charge density on solid-liquid interfaces by modulating the electrical double layer.

PubMed

Moon, Jong Kyun; Song, Myung Won; Pak, Hyuk Kyu

2015-05-20

A solid surface in contact with water or aqueous solution usually carries specific electric charges. These surface charges attract counter ions from the liquid side. Since the geometry of opposite charge distribution parallel to the solid-liquid interface is similar to that of a capacitor, it is called an electrical double layer capacitor (EDLC). Therefore, there is an electrical potential difference across an EDLC in equilibrium. When a liquid bridge is formed between two conducting plates, the system behaves as two serially connected EDLCs. In this work, we propose a new method for investigating the surface charge density on solid-liquid interfaces. By mechanically modulating the electrical double layers and simultaneously applying a dc bias voltage across the plates, an ac electric current can be generated. By measuring the voltage drop across a load resistor as a function of bias voltage, we can study the surface charge density on solid-liquid interfaces. Our experimental results agree very well with the simple equivalent electrical circuit model proposed here. Furthermore, using this method, one can determine the polarity of the adsorbed state on the solid surface depending on the material used. We expect this method to aid in the study of electrical phenomena on solid-liquid interfaces.

A Theoretical Study of Love Wave Sensors Based on ZnO–Glass Layered Structures for Application to Liquid Environments

PubMed Central

Caliendo, Cinzia; Hamidullah, Muhammad

2016-01-01

The propagation of surface acoustic Love modes along ZnO/glass-based structures was modeled and analysed with the goal of designing a sensor able to detect changes in the environmental parameters, such as liquid viscosity changes and minute amounts of mass supported in the viscous liquid medium. Love mode propagation was modeled by numerically solving the system of coupled electro-mechanical field equations and Navier–Stokes equations. The phase and group velocities and the attenuation of the acoustic wave propagating along the 30° tilted c-axis ZnO/glass structure contacting a viscous non-conductive liquid were calculated for different ZnO guiding layer thicknesses, added mass thicknesses, and liquid viscosity and density. The three sensor responses, i.e., the wave phase and group velocity, and attenuation changes are calculated for different environmental parameters and related to the sensor velocity and attenuation sensitivities. The resulted sensitivities to liquid viscosity and added mass were optimized by adjusting the ZnO guiding layer thickness corresponding to a sensitivity peak. The present analysis is valuable for the manufacture and application of the ZnO-glass structure Love wave sensors for the detection of liquid properties, such as viscosity, density and mass anchored to the sensor surface. PMID:27918419

Electrodeposition of Polymer Nanostructures using Three Diffuse Double Layers: Polymerization beyond the Liquid/Liquid Interfaces

NASA Astrophysics Data System (ADS)

Divya, Velpula; Sangaranarayanan, M. V.

2018-04-01

Nanostructured conducting polymers have received immense attention during the past few decades on account of their phenomenal usefulness in diverse contexts, while the interface between two immiscible liquids is of great interest in chemical and biological applications. Here we propose a novel Electrode(solid)/Electrolyte(aqueous)/Electrolyte(organic) Interfacial assembly for the synthesis of polymeric nanostructures using a novel concept of three diffuse double layers. There exist remarkable differences between the morphologies of the polymers synthesized using the conventional electrode/electrolyte method and that of the new approach. In contrast to the commonly employed electrodeposition at liquid/liquid interfaces, these polymer modified electrodes can be directly employed in diverse applications such as sensors, supercapacitors etc.

Stable Liquid Jets Bouncing off Soft Gels

NASA Astrophysics Data System (ADS)

Daniel, Dan; Yao, Xi; Aizenberg, Joanna

2018-01-01

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

Tidal Heating in Multilayered Terrestrial Exoplanets

NASA Technical Reports Server (NTRS)

Henning, Wade G.; Hurford, Terry

2014-01-01

The internal pattern and overall magnitude of tidal heating for spin-synchronous terrestrial exoplanets from 1 to 2.5 R(sub E) is investigated using a propagator matrix method for a variety of layer structures. Particular attention is paid to ice-silicate hybrid super-Earths, where a significant ice mantle is modeled to rest atop an iron-silicate core, and may or may not contain a liquid water ocean. We find multilayer modeling often increases tidal dissipation relative to a homogeneous model, across multiple orbital periods, due to the ability to include smaller volume low viscosity regions, and the added flexure allowed by liquid layers. Gradations in parameters with depth are explored, such as allowed by the Preliminary Earth Reference Model. For ice-silicate hybrid worlds, dramatically greater dissipation is possible beyond the case of a silicate mantle only, allowing non-negligible tidal activity to extend to greater orbital periods than previously predicted. Surface patterns of tidal heating are found to potentially be useful for distinguishing internal structure. The influence of ice mantle depth and water ocean size and position are shown for a range of forcing frequencies. Rates of orbital circularization are found to be 10-100 times faster than standard predictions for Earth-analog planets when interiors are moderately warmer than the modern Earth, as well as for a diverse range of ice-silicate hybrid super-Earths. Circularization rates are shown to be significantly longer for planets with layers equivalent to an ocean-free modern Earth, as well as for planets with high fractions of either ice or silicate melting.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Olivieri, Giorgia; Brown, Matthew A., E-mail: matthew.brown@mat.ethz.ch; Parry, Krista M.

Over the past decade, energy-dependent ambient pressure X-ray photoelectron spectroscopy (XPS) has emerged as a powerful analytical probe of the ion spatial distributions at the vapor (vacuum)-aqueous electrolyte interface. These experiments are often paired with complementary molecular dynamics (MD) simulations in an attempt to provide a complete description of the liquid interface. There is, however, no systematic protocol that permits a straightforward comparison of the two sets of results. XPS is an integrated technique that averages signals from multiple layers in a solution even at the lowest photoelectron kinetic energies routinely employed, whereas MD simulations provide a microscopic layer-by-layer descriptionmore » of the solution composition near the interface. Here, we use the National Institute of Standards and Technology database for the Simulation of Electron Spectra for Surface Analysis (SESSA) to quantitatively interpret atom-density profiles from MD simulations for XPS signal intensities using sodium and potassium iodide solutions as examples. We show that electron inelastic mean free paths calculated from a semi-empirical formula depend strongly on solution composition, varying by up to 30% between pure water and concentrated NaI. The XPS signal thus arises from different information depths in different solutions for a fixed photoelectron kinetic energy. XPS signal intensities are calculated using SESSA as a function of photoelectron kinetic energy (probe depth) and compared with a widely employed ad hoc method. SESSA simulations illustrate the importance of accounting for elastic-scattering events at low photoelectron kinetic energies (<300 eV) where the ad hoc method systematically underestimates the preferential enhancement of anions over cations. Finally, some technical aspects of applying SESSA to liquid interfaces are discussed.« less

Synchrotron Radiation Microcomputed Tomography Guided Chromatographic Analysis for Displaying the Material Distribution in Tablets.

PubMed

Zhang, Liu; Wu, Li; Wang, Caifen; Zhang, Guoqing; Yu, Lin; Li, Haiyan; Maharjan, Abi; Tang, Yan; He, Dunwei; York, Peter; Sun, Huimin; Yin, Xianzhen; Zhang, Jiwen; Sun, Lixin

2018-03-06

One unusual and challenging scientific field that has received only cursory attention to date is the three-dimensional (3D) microstructure and spatial distribution of drug(s) and formulation materials in solid dosage forms. This study aims to provide deeper insight into the relationships between the microstructure of multiple-unit pellet system (MUPS) tablets and the spatial distribution of the active pharmaceutical ingredient (API) and excipients to facilitate the design of quantitative models for drug delivery systems. Synchrotron radiation X-ray microcomputed tomography (SR-μCT) was established as a 3D structure elucidation technique, which, in conjunction with liquid chromatography coupled to mass spectrometry (LC-MS) or liquid chromatography with evaporative light-scattering detector (LC-ELSD) enables chemical analysis of tablets. On the basis of the specific interior construction of theophylline MUPS tablets, the spatial distribution of materials was acquired by quantifying microregion samples that had been validated by SR-μCT for their locations in the MUPS tablets. The 3D structure of the MUPS tablets was catalogued as three structural domains: a matrix layer (ML), a protective cushion layer (PCL), and pellets (PL). Compared with the components in the ML, components in the PL had a larger proportion of theophylline, sucrose, and diethyl phthalate and a smaller proportion of lactose and sodium lauryl sulfate, whereas glyceryl monostearate was found to account for a large portion of the PCL. Microstructural characterization-guided zonal chemical determination represents a new approach for quality assessment and the development of drug delivery systems with in-depth insight into their constituent layers on a new scale.

Fabrication of ultrathin multilayered superomniphobic nanocoatings by liquid flame spray, atomic layer deposition, and silanization.

PubMed

Sorvali, Miika; Vuori, Leena; Pudas, Marko; Haapanen, Janne; Mahlberg, Riitta; Ronkainen, Helena; Honkanen, Mari; Valden, Mika; Mäkelä, Jyrki M

2018-05-04

Superomniphobic, i.e. liquid-repellent, surfaces have been an interesting area of research during recent years due to their various potential applications. However, producing such surfaces, especially on hard and resilient substrates like stainless steel, still remains challenging. We present a stepwise fabrication process of a multilayered nanocoating on a stainless steel substrate, consisting of a nanoparticle layer, a nanofilm, and a layer of silane molecules. Liquid flame spray was used to deposit a TiO 2 nanoparticle layer as the bottom layer for producing a suitable surface structure. The interstitial Al 2 O 3 nanofilm, fabricated by atomic layer deposition (ALD), stabilized the nanoparticle layer, and the topmost fluorosilane layer lowered the surface energy of the coating for enhanced omniphobicity. The coating was characterized with field emission scanning electron microscopy, focused ion beam scanning electron microscopy, x-ray photoelectron spectroscopy, contact angle (CA) and sliding angle (SA) measurements, and microscratch testing. The widely recognized requirements for superrepellency, i.e. CA > 150° and SA < 10°, were achieved for deioinized water, diiodomethane, and ethylene glycol. The mechanical stability of the coating could be varied by tuning the thickness of the ALD layer at the expense of repellency. To our knowledge, this is the thinnest superomniphobic coating reported so far, with the average thickness of about 70 nm.

Fabrication of ultrathin multilayered superomniphobic nanocoatings by liquid flame spray, atomic layer deposition, and silanization

NASA Astrophysics Data System (ADS)

Sorvali, Miika; Vuori, Leena; Pudas, Marko; Haapanen, Janne; Mahlberg, Riitta; Ronkainen, Helena; Honkanen, Mari; Valden, Mika; Mäkelä, Jyrki M.

2018-05-01

Superomniphobic, i.e. liquid-repellent, surfaces have been an interesting area of research during recent years due to their various potential applications. However, producing such surfaces, especially on hard and resilient substrates like stainless steel, still remains challenging. We present a stepwise fabrication process of a multilayered nanocoating on a stainless steel substrate, consisting of a nanoparticle layer, a nanofilm, and a layer of silane molecules. Liquid flame spray was used to deposit a TiO2 nanoparticle layer as the bottom layer for producing a suitable surface structure. The interstitial Al2O3 nanofilm, fabricated by atomic layer deposition (ALD), stabilized the nanoparticle layer, and the topmost fluorosilane layer lowered the surface energy of the coating for enhanced omniphobicity. The coating was characterized with field emission scanning electron microscopy, focused ion beam scanning electron microscopy, x-ray photoelectron spectroscopy, contact angle (CA) and sliding angle (SA) measurements, and microscratch testing. The widely recognized requirements for superrepellency, i.e. CA > 150° and SA < 10°, were achieved for deioinized water, diiodomethane, and ethylene glycol. The mechanical stability of the coating could be varied by tuning the thickness of the ALD layer at the expense of repellency. To our knowledge, this is the thinnest superomniphobic coating reported so far, with the average thickness of about 70 nm.

Martian Gullies and Groundwater: A Series of Unfortunate Exceptions

NASA Technical Reports Server (NTRS)

Treiman, A. H.

2005-01-01

Gullies are commonly inferred to represent debris flows, lubricated and carried by liquid water that flowed from underground. The inference of groundwater, based principally on the apparent initiation of gullies at specific bedrock layers, has not been considered for consistency with local geology. Here, I examine gully occurrences for: presence of impermeable layers (aquicludes) in the subsurface, that the layers not tilt away from the gully-bearing walls, and that liquid water could have been available at or above the gully elevations.

The effect of viscoelasticity on the stability of a pulmonary airway liquid layer

NASA Astrophysics Data System (ADS)

Halpern, David; Fujioka, Hideki; Grotberg, James B.

2010-01-01

The lungs consist of a network of bifurcating airways that are lined with a thin liquid film. This film is a bilayer consisting of a mucus layer on top of a periciliary fluid layer. Mucus is a non-Newtonian fluid possessing viscoelastic characteristics. Surface tension induces flows within the layer, which may cause the lung's airways to close due to liquid plug formation if the liquid film is sufficiently thick. The stability of the liquid layer is also influenced by the viscoelastic nature of the liquid, which is modeled using the Oldroyd-B constitutive equation or as a Jeffreys fluid. To examine the role of mucus alone, a single layer of a viscoelastic fluid is considered. A system of nonlinear evolution equations is derived using lubrication theory for the film thickness and the film flow rate. A uniform film is initially perturbed and a normal mode analysis is carried out that shows that the growth rate g for a viscoelastic layer is larger than for a Newtonian fluid with the same viscosity. Closure occurs if the minimum core radius, Rmin(t), reaches zero within one breath. Solutions of the nonlinear evolution equations reveal that Rmin normally decreases to zero faster with increasing relaxation time parameter, the Weissenberg number We. For small values of the dimensionless film thickness parameter ɛ, the closure time, tc, increases slightly with We, while for moderate values of ɛ, ranging from 14% to 18% of the tube radius, tc decreases rapidly with We provided the solvent viscosity is sufficiently small. Viscoelasticity was found to have little effect for ɛ >0.18, indicating the strong influence of surface tension. The film thickness parameter ɛ and the Weissenberg number We also have a significant effect on the maximum shear stress on tube wall, max(τw), and thus, potentially, an impact on cell damage. Max(τw) increases with ɛ for fixed We, and it decreases with increasing We for small We provided the solvent viscosity parameter is sufficiently small. For large ɛ ≈0.2, there is no significant difference between the Newtonian flow case and the large We cases.

Liquid Crystalline Behavior and Related Properties of Colloidal Systems of Inorganic Oxide Nanosheets

PubMed Central

Nakato, Teruyuki; Miyamoto, Nobuyoshi

2009-01-01

Inorganic layered crystals exemplified by clay minerals can be exfoliated in solvents to form colloidal dispersions of extremely thin inorganic layers that are called nanosheets. The obtained “nanosheet colloids” form lyotropic liquid crystals because of the highly anisotropic shape of the nanosheets. This system is a rare example of liquid crystals consisting of inorganic crystalline mesogens. Nanosheet colloids of photocatalytically active semiconducting oxides can exhibit unusual photoresponses that are not observed for organic liquid crystals. This review summarizes experimental work on the phase behavior of the nanosheet colloids as well as photochemical reactions observed in the clay and semiconducting nanosheets system.

Nano-scale luminescence characterization of individual InGaN/GaN quantum wells stacked in a microcavity using scanning transmission electron microscope cathodoluminescence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmidt, Gordon, E-mail: Gordon.Schmidt@ovgu.de; Müller, Marcus; Veit, Peter

2014-07-21

Using cathodoluminescence spectroscopy directly performed in a scanning transmission electron microscope at liquid helium temperatures, the optical and structural properties of a 62 InGaN/GaN multiple quantum well embedded in an AlInN/GaN based microcavity are investigated at the nanometer scale. We are able to spatially resolve a spectral redshift between the individual quantum wells towards the surface. Cathodoluminescence spectral linescans allow directly visualizing the critical layer thickness in the quantum well stack resulting in the onset of plastic relaxation of the strained InGaN/GaN system.

Improving the light-emitting properties of single-layered polyfluorene light-emitting devices by simple ionic liquid blending

NASA Astrophysics Data System (ADS)

Horike, Shohei; Nagaki, Hiroto; Misaki, Masahiro; Koshiba, Yasuko; Morimoto, Masahiro; Fukushima, Tatsuya; Ishida, Kenji

2018-03-01

This paper describes an evaluation of ionic liquids (ILs) as potential electrolytes for single-layered light-emitting devices with good emission performance. As optoelectronic devices continue to grow in abundance, high-performance light-emitting devices with a single emission layer are becoming increasingly important for low-cost production. We show that a simple technique of osmosing IL into the polymer layer can result in high luminous efficiency and good response times of single-layered light-emitting polymers, even without the additional stacking of charge carrier injection and transport layers. The IL contributions to the light-emission of the polymer are discussed from the perspectives of energy diagrams and of the electric double layers on the electrodes. Our findings enable a faster, cheaper, and lower-in-waste production of light-emitting devices.

Thermal stratification in LH2 tank of cryogenic propulsion stage tested in ISRO facility

NASA Astrophysics Data System (ADS)

Xavier, M.; Raj, R. Edwin; Narayanan, V.

2017-02-01

Liquid oxygen and hydrogen are used as oxidizer and fuel respectively in cryogenic propulsion system. These liquids are stored in foam insulated tanks of cryogenic propulsion system and are pressurized using warm pressurant gas supplied for tank pressure maintenance during cryogenic engine operation. Heat leak to cryogenic propellant tank causes buoyancy driven liquid stratification resulting in formation of warm liquid stratum at liquid free surface. This warm stratum is further heated by the admission of warm pressurant gas for tank pressurization during engine operation. Since stratified layer temperature has direct bearing on the cavitation free operation of turbo pumps integrated in cryogenic engine, it is necessary to model the thermal stratification for predicting stratified layer temperature and mass of stratified liquid in tank at the end of engine operation. These inputs are required for estimating the minimum pressure to be maintained by tank pressurization system. This paper describes configuration of cryogenic stage for ground qualification test, stage hot test sequence, a thermal model and its results for a foam insulated LH2 tank subjected to heat leak and pressurization with hydrogen gas at 200 K during liquid outflow at 38 lps for engine operation. The above model considers buoyancy flow in free convection boundary layer caused by heat flux from tank wall and energy transfer from warm pressurant gas etc. to predict temperature of liquid stratum and mass of stratified liquid in tank at the end of engine operation in stage qualification tests carried out in ISRO facility.

Quantitative analysis of total reflection X-ray fluorescence from finely layered structures using XeRay.

PubMed

Gong, Zhiliang; Kerr, Daniel; Hwang, Hyeondo Luke; Henderson, J Michael; Suwatthee, Tiffany; Slaw, Benjamin R; Cao, Kathleen D; Lin, Binhua; Bu, Wei; Lee, Ka Yee C

2017-03-01

Total reflection x-ray fluorescence (TXRF) is a widely applicable experimental technique for studying chemical element distributions across finely layered structures at extremely high sensitivity. To promote and facilitate scientific discovery using TXRF, we developed a MATLAB-based software package with a graphical user interface, named XeRay, for quick, accurate, and intuitive data analysis. XeRay lets the user model any layered system, each layer with its independent chemical composition and thickness, and enables fine-tuned data fitting. The accuracy of XeRay has been tested in the analysis of TXRF data from both air/liquid interface and liquid/liquid interfacial studies and has been compared to literature results. In an air/liquid interface study, Ca 2+ sequestration was measured at a Langmuir monolayer of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphatidic acid (SOPA) on a buffer solution of 1 mM CaCl 2 at pH 7.5. Data analysis with XeRay reveals that each 1 nm 2 of interfacial area contains 2.38 ± 0.06 Ca 2+ ions, which corresponds to a 1:1 ratio between SOPA headgroups and Ca 2+ ions, consistent with several earlier reports. For the liquid/liquid interface study of Sr 2+ enrichment at the dodecane/surfactant/water interface, analysis using XeRay gives a surface enrichment of Sr 2+ at 68 -5 +6 Å 2 per ion, consistent with the result published for the same dataset.

Quantitative analysis of total reflection X-ray fluorescence from finely layered structures using XeRay

NASA Astrophysics Data System (ADS)

Gong, Zhiliang; Kerr, Daniel; Hwang, Hyeondo Luke; Henderson, J. Michael; Suwatthee, Tiffany; Slaw, Benjamin R.; Cao, Kathleen D.; Lin, Binhua; Bu, Wei; Lee, Ka Yee C.

2017-03-01

Total reflection x-ray fluorescence (TXRF) is a widely applicable experimental technique for studying chemical element distributions across finely layered structures at extremely high sensitivity. To promote and facilitate scientific discovery using TXRF, we developed a MATLAB-based software package with a graphical user interface, named XeRay, for quick, accurate, and intuitive data analysis. XeRay lets the user model any layered system, each layer with its independent chemical composition and thickness, and enables fine-tuned data fitting. The accuracy of XeRay has been tested in the analysis of TXRF data from both air/liquid interface and liquid/liquid interfacial studies and has been compared to literature results. In an air/liquid interface study, Ca2+ sequestration was measured at a Langmuir monolayer of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphatidic acid (SOPA) on a buffer solution of 1 mM CaCl2 at pH 7.5. Data analysis with XeRay reveals that each 1 nm2 of interfacial area contains 2.38 ± 0.06 Ca2+ ions, which corresponds to a 1:1 ratio between SOPA headgroups and Ca2+ ions, consistent with several earlier reports. For the liquid/liquid interface study of Sr2+ enrichment at the dodecane/surfactant/water interface, analysis using XeRay gives a surface enrichment of Sr2+ at 68-5+6 Å2 per ion, consistent with the result published for the same dataset.

Quantitative analysis of total reflection X-ray fluorescence from finely layered structures using XeRay

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gong, Zhiliang; Kerr, Daniel; Hwang, Hyeondo Luke

Total reflection x-ray fluorescence (TXRF) is a widely applicable experimental technique for studying chemical element distributions across finely layered structures at extremely high sensitivity. To promote and facilitate scientific discovery using TXRF, we developed a MATLAB-based software package with a graphical user interface, named XeRay, for quick, accurate, and intuitive data analysis. XeRay lets the user model any layered system, each layer with its independent chemical composition and thickness, and enables fine-tuned data fitting. The accuracy of XeRay has been tested in the analysis of TXRF data from both air/liquid interface and liquid/liquid interfacial studies and has been compared tomore » literature results. In an air/liquid interface study, Ca2+ sequestration was measured at a Langmuir monolayer of 1-stearoyl-2-oleoyl-sn-glycero-3-phosphatidic acid (SOPA) on a buffer solution of 1 mM CaCl2 at pH 7.5. Data analysis with XeRay reveals that each 1 nm2 of interfacial area contains 2.38 ± 0.06 Ca2+ ions, which corresponds to a 1:1 ratio between SOPA headgroups and Ca2+ ions, consistent with several earlier reports. For the liquid/liquid interface study of Sr2+ enrichment at the dodecane/surfactant/water interface, analysis using XeRay gives a surface enrichment of Sr2+ at 68+6-568-5+6 Å2 per ion, consistent with the result published for the same dataset.« less

Liquid phase heteroepitaxial growth on convex substrate using binary phase field crystal model

NASA Astrophysics Data System (ADS)

Lu, Yanli; Zhang, Tinghui; Chen, Zheng

2018-06-01

The liquid phase heteroepitaxial growth on convex substrate is investigated with the binary phase field crystal (PFC) model. The paper aims to focus on the transformation of the morphology of epitaxial films on convex substrate with two different radiuses of curvature (Ω) as well as influences of substrate vicinal angles on films growth. It is found that films growth experience different stages on convex substrate with different radiuses of curvature (Ω). For Ω = 512 Δx , the process of epitaxial film growth includes four stages: island coupled with layer-by-layer growth, layer-by-layer growth, island coupled with layer-by-layer growth, layer-by-layer growth. For Ω = 1024 Δx , film growth only experience islands growth and layer-by-layer growth. Also, substrate vicinal angle (π) is an important parameter for epitaxial film growth. We find the film can grow well when π = 2° for Ω = 512 Δx , while the optimized film can be obtained when π = 4° for Ω = 512 Δx .

In situ monitoring of liquid phase electroepitaxial growth

NASA Technical Reports Server (NTRS)

Okamoto, A.; Isozumi, S.; Lagowski, J.; Gatos, H. C.

1982-01-01

In situ monitoring of the layer thickness during liquid phase electroepitaxy (LPEE) was achieved with a submicron resolution through precise resistance measurements. The new approach to the study and control of LPEE was applied to growth of undoped and Ge-doped GaAs layers. The in situ determined growth kinetics was found to be in excellent agreement with theory.

Coated armor system and process for making the same

DOEpatents

Chu, Henry S.; Lillo, Thomas M.; McHugh, Kevin M.

2010-11-23

An armor system and method involves providing a core material and a stream of atomized coating material that comprises a liquid fraction and a solid fraction. An initial layer is deposited on the core material by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is less than the liquid fraction of the stream of atomized coating material on a weight basis. An outer layer is then deposited on the initial layer by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is greater than the liquid fraction of the stream of atomized coating material on a weight basis.

Armor systems including coated core materials

DOEpatents

Chu, Henry S [Idaho Falls, ID; Lillo, Thomas M [Idaho Falls, ID; McHugh, Kevin M [Idaho Falls, ID

2012-07-31

An armor system and method involves providing a core material and a stream of atomized coating material that comprises a liquid fraction and a solid fraction. An initial layer is deposited on the core material by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is less than the liquid fraction of the stream of atomized coating material on a weight basis. An outer layer is then deposited on the initial layer by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is greater than the liquid fraction of the stream of atomized coating material on a weight basis.

Armor systems including coated core materials

DOEpatents

Chu, Henry S; Lillo, Thomas M; McHugh, Kevin M

2013-10-08

An armor system and method involves providing a core material and a stream of atomized coating material that comprises a liquid fraction and a solid fraction. An initial layer is deposited on the core material by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is less than the liquid fraction of the stream of atomized coating material on a weight basis. An outer layer is then deposited on the initial layer by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is greater than the liquid fraction of the stream of atomized coating material on a weight basis.

Effect of Prestresses on the Dispersion of Quasi-Lamb Waves in the System Consisting of an Ideal Liquid Layer and a Compressible Elastic Layer

NASA Astrophysics Data System (ADS)

Bagno, A. M.

2017-03-01

The propagation of quasi-Lamb waves in a prestrained compressible elastic layer interacting with a layer of an ideal compressible fluid is studied. The three-dimensional equations of linearized elasticity and the assumption of finite strains for the elastic layer and the three-dimensional linearized Euler equations for the fluid are used. The dispersion curves for the quasi-Lamb modes are plotted over a wide frequency range. The effect of prestresses and the thickness of the elastic and liquid layers on the frequency spectrum of normal quasi-Lamb waves is analyzed. The localization properties of the lower quasi-Lamb modes in the elastic-fluid waveguides are studied. The numerical results are presented in the form of graphs and analyzed

A ceramic/slag interface as an analog for accretion of hot refractory objects and rim formation

NASA Technical Reports Server (NTRS)

Paque, J. M.; Bunch, T. E.

1994-01-01

Refractory inclusions or Ca-Al-rich inclusions (CAI's) from carbonaceous chondrites span a wide range of bulk compositions that cannot be explained either by segregation from a gas of solar composition at different points in the condensation sequence or by fractional crystallization from a parent liquid. CAI's are commonly rimmed by Wark-Lovering (W-L) rims, a series of nearly monomineralic layers that have been a source of controversy since the variety of rim sequences occurring on different types of CAI's from Allende were described. The origin of these distinctive features has not yet been resolved, with proponents of accretion, condensation, flash heating, ablation, evaporation, etc. Rims have generated considerable interest because they potentially contain clues to conditions experienced by CAI's after the formation of the inclusion and prior to incorporation into the parent body. Ceramic bricks in contact with hot steel slag may produce reaction products in rimlike fashion similar to those found in CAI's. The similarity between the mineralogy of blast furnace slags and CAI's has long been recognized, with both containing unusual phases not found in terrestrial materials. We provide here a comparison between a ceramic brick/slag multiple-layered interface and a multiple-layered interface between a melilite-perovskite object and a melilite-spinel object in the Allende inclusion USNM 4691-1. These results have implications in interpreting the origin of rims and the textures and compositions of CAI's.

Apparatus and process for freeform fabrication of composite reinforcement preforms

NASA Technical Reports Server (NTRS)

Yang, Junsheng (Inventor); Wu, Liangwei (Inventor); Liu, Junhai (Inventor); Jang, Bor Z. (Inventor)

2001-01-01

A solid freeform fabrication process and apparatus for making a three-dimensional reinforcement shape. The process comprises the steps of (1) operating a multiple-channel material deposition device for dispensing a liquid adhesive composition and selected reinforcement materials at predetermined proportions onto a work surface; (2) during the material deposition process, moving the deposition device and the work surface relative to each other in an X-Y plane defined by first and second directions and in a Z direction orthogonal to the X-Y plane so that the materials are deposited to form a first layer of the shape; (3) repeating these steps to deposit multiple layers for forming a three-dimensional preform shape; and (4) periodically hardening the adhesive to rigidize individual layers of the preform. These steps are preferably executed under the control of a computer system by taking additional steps of (5) creating a geometry of the shape on the computer with the geometry including a plurality of segments defining the preform shape and each segment being preferably coded with a reinforcement composition defining a specific proportion of different reinforcement materials; (6) generating programmed signals corresponding to each of the segments in a predetermined sequence; and (7) moving the deposition device and the work surface relative to each other in response to these programmed signals. Preferably, the system is also operated to generate a support structure for any un-supported feature of the 3-D preform shape.

Composite aerogel insulation for cryogenic liquid storage

NASA Astrophysics Data System (ADS)

Kyeongho, Kim; Hyungmook, Kang; Soojin, Shin; In Hwan, Oh; Changhee, Son; Hyung, Cho Yun; Yongchan, Kim; Sarng Woo, Karng

2017-02-01

High porosity materials such as aerogel known as a good insulator in a vacuum range (10-3 ∼ 1 Torr) was widely used to storage and to transport cryogenic fluids. It is necessary to be investigated the performance of aerogel insulations for cryogenic liquid storage in soft vacuum range to atmospheric pressure. A one-dimensional insulating experimental apparatus was designed and fabricated to consist of a cold mass tank, a heat absorber and an annular vacuum space with 5-layer (each 10 mm thickness) of the aerogel insulation materials. Aerogel blanket for cryogenic (used maximum temperature is 400K), aerogel blanket for normal temperature (used maximum temperature is 923K), and combination of the two kinds of aerogel blankets were 5-layer laminated between the cryogenic liquid wall and the ambient wall in vacuum space. Also, 1-D effective thermal conductivities of the insulation materials were evaluated by measuring boil-off rate from liquid nitrogen and liquid argon. In this study, the effective thermal conductivities and the temperature-thickness profiles of the two kinds of insulators and the layered combination of the two different aerogel blankets were presented.

Detecting a liquid and solid H2O layer by geophysical methods

NASA Astrophysics Data System (ADS)

Yoshikawa, K.; Romanovsky, V.; Tsapin, A.; Brown, J.

2002-12-01

The objective is to detect the hydrological and cryological structure of the cold continuous permafrost subsurface using geophysical methods. We believe that a lot of water potentially exists as solid and liquid phases underground on Mars. It is likely that the liquid fluid would be high in saline concentration (brine). The ground freezing process involves many hydrological processes including enrichment of the brine layer. The brine layer is an important environment for ancient and/or current life to exist on terrestrial permafrost regions. The existence of a Martian brine layer would increase the possibility of the existence of life, as on Earth. In situ electric resistivity measurement will be the most efficient method to determine brine layer as well as massive H2O ice in the permafrost. However, the wiring configuration is unlikely to operate on the remote planetary surface. Satellite-born Radar and/or EM methods will be the most accessible methods for detecting the hydrological and cryological structure. We are testing several geophysical methods at the brine layer site in Barrow and massive pingo ice site in Fairbanks, Alaska. The radar system is affected by the dielectric properties of subsurface materials, which allows for evidence of liquid phase in the frozen ground. The dielectric constant varies greatly between liquid water and frozen ground. The depth of the terrestrial (and probably Martian) brine layer is frequently located deeper than the maximum detecting depth of the impulse type of the ground penetrating radar system. Once we develop a radar system with a deeper penetrating capability (Lower frequency), the dispersion of the ground ice will be the key function for interpretation of these signals. We will improve and use radar signals to understand the hydrological and cryological structure in the permafrost. The core samples and borehole temperature data validate these radar signals.

Surface layering and melting in an ionic liquid studied by resonant soft X-ray reflectivity

PubMed Central

Mezger, Markus; Ocko, Benjamin M.; Reichert, Harald; Deutsch, Moshe

2013-01-01

The molecular-scale structure of the ionic liquid [C18mim]+[FAP]− near its free surface was studied by complementary methods. X-ray absorption spectroscopy and resonant soft X-ray reflectivity revealed a depth-decaying near-surface layering. Element-specific interfacial profiles were extracted with submolecular resolution from energy-dependent soft X-ray reflectivity data. Temperature-dependent hard X-ray reflectivity, small- and wide-angle X-ray scattering, and infrared spectroscopy uncovered an intriguing melting mechanism for the layered region, where alkyl chain melting drove a negative thermal expansion of the surface layer spacing. PMID:23431181

Approximate transient and long time limit solutions for the band broadening induced by the thin sidewall-layer in liquid chromatography columns.

PubMed

Broeckhoven, Ken; Desmet, Gert

2007-11-16

Using a combination of both analytical and numerical techniques, approximate analytical expressions have been established for the transient and long time limit band broadening, originating from the presence of a thin disturbed sidewall layer in liquid chromatography columns, including packed, monolithic as well as microfabricated columns. The established expressions can be used to compare the importance of a thin disturbed sidewall layer with that of other radial heterogeneity effects (such as transcolumn packing density variations due to the relief of packing stresses). The expressions are independent of the actual velocity profile inside the layer as long as the disturbed sidewall layer occupies less than 2.5% of the column width.

Hydroelastic Oscillations of a Circular Plate, Resting on Winkler Foundation

NASA Astrophysics Data System (ADS)

Kondratov, D. V.; Mogilevich, L. I.; Popov, V. S.; Popova, A. A.

2018-01-01

The forced hydroelastic oscillations of a circular plate resting on elastic foundation are investigated. The oscillations are caused by a stamp vibration under interaction with a plate through a thin layer of viscous incompressible liquid. The axis-symmetric problem for the regime of the steady-state harmonic oscillations is considered. On the basis of hydroelasticity problem solution the laws of plate deflection and pressure in the liquid are found. The functions of the amplitudes deflection distribution and liquid pressure along the plate are constructed. The presented mathematical model provides for investigating viscous liquid layer interaction dynamics with a circular plate resting on an elastic foundation. The above-mentioned model makes it possible to define the plate oscillations resonance frequencies and the corresponding amplitudes of deflection and liquid pressure, as well.

Explosive fragmentation of liquids in spherical geometry

NASA Astrophysics Data System (ADS)

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

2017-05-01

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Eun-Kyeong; Yeong Kim, Ji; Sub Kim, Sang, E-mail: sangsub@inha.ac.kr

We describe the preparation of superhydrophobic SiO{sub 2} layers through a combination of surface roughness and fluorination. Electrospraying SiO{sub 2} precursor solutions that were prepared by a sol-gel route and included trichloro(1H,1H,2H,2H-perfluorooctyl)silane as a fluorination source produced highly rough, fluorinated SiO{sub 2} layers. In sharp contrast to the fluorinated flat SiO{sub 2} layer, the fluorinated rough SiO{sub 2} layer showed much enhanced repellency toward liquid droplets of different surface tensions. The surface fraction and the work of adhesion of the superhydrophobic SiO{sub 2} layers were determined, respectively, based on Cassie-Baxter and Young-Dupre equations. The satisfactory long-term stability for 30 days,more » the ultraviolet resistance and the thermal stability up to 400 {sup o}C of the superhydrophobic SiO{sub 2} layers prepared in this work confirm a promising practical application. - Graphical abstract: A schematic illustration of the electrospray deposition used for preparing SiO{sub 2} layers. Shapes of liquid droplets of water, glycerol, coffee, juice and milk created on the fluorinated rough SiO{sub 2} layer deposited on a silicon wafer. Highlights: Black-Right-Pointing-Pointer Superhydrophobic SiO{sub 2} layers are realized by a combination of surface roughness and fluorination. Black-Right-Pointing-Pointer The fluorinated rough SiO{sub 2} layer shows enhanced repellency toward various liquid droplets. Black-Right-Pointing-Pointer The wetting behavior is explained based on Cassie-Baxter and Young-Dupre equations. Black-Right-Pointing-Pointer The superhydrophobic SiO{sub 2} layers confirm a promising practical application.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myers, Tanya L.; Tonkyn, Russell G.; Danby, Tyler O.

For optical modeling and other purposes, we have created a library of 57 liquids for which we have measured the complex optical constants n and k. These liquids vary in their nature, ranging in properties including chemical structure, optical band strength, volatility and viscosity. By obtaining the optical constants one can in principle model most optical phenomena in media and at interfaces including reflection, refraction and dispersion. Based on the original methods of J.E. Bertie et al.1 [1Bert1], we have developed improved protocols using multiple path lengths to determine the optical constants n/k for dozens of liquids, including inorganic, organicmore » and organophosphorus compounds. Detailed descriptions of the measurement and data reduction protocols are discussed; agreement of the derived optical constant n and k values with literature values are presented. We also present results using the n/k values as applied to an optical modeling scenario whereby the derived data are presented and tested for models of 1 µm and 100 µm layers for DMMP (dimethyl methyl phosphonate) on both metal (aluminum) and dielectric (soda lime glass) substrates to show substantial differences between the reflected signal from highly reflective substrates and less-reflective substrates.« less

Exceptionally Slow Movement of Gold Nanoparticles at a Solid/Liquid Interface Investigated by Scanning Transmission Electron Microscopy.

PubMed

Verch, Andreas; Pfaff, Marina; de Jonge, Niels

2015-06-30

Gold nanoparticles were observed to move at a liquid/solid interface 3 orders of magnitude slower than expected for the movement in a bulk liquid by Brownian motion. The nanoscale movement was studied with scanning transmission electron microscopy (STEM) using a liquid enclosure consisting of microchips with silicon nitride windows. The experiments involved a variation of the electron dose, the coating of the nanoparticles, the surface charge of the enclosing membrane, the viscosity, and the liquid thickness. The observed slow movement was not a result of hydrodynamic hindrance near a wall but instead explained by the presence of a layer of ordered liquid exhibiting a viscosity 5 orders of magnitude larger than a bulk liquid. The increased viscosity presumably led to a dramatic slowdown of the movement. The layer was formed as a result of the surface charge of the silicon nitride windows. The exceptionally slow motion is a crucial aspect of electron microscopy of specimens in liquid, enabling a direct observation of the movement and agglomeration of nanoscale objects in liquid.

Visualization of boundary-layer development on turbomachine blades with liquid crystals

NASA Technical Reports Server (NTRS)

Vanzante, Dale E.; Okiishi, Theodore H.

1991-01-01

This report documents a study of the use of liquid crystals to visualize boundary layer development on a turbomachine blade. A turbine blade model in a linear cascade of blades was used for the tests involved. Details of the boundary layer development on the suction surface of the turbine blade model were known from previous research. Temperature sensitive and shear sensitive liquid crystals were tried as visual agents. The temperature sensitive crystals were very effective in their ability to display the location of boundary layer flow separation and reattachment. Visualization of natural transition from laminar to turbulent boundary layer flow with the temperature sensitive crystals was possible but subtle. The visualization of separated flow reattachment with the shear sensitive crystals was easily accomplished when the crystals were allowed to make a transition from the focal-conic to a Grandjean texture. Visualization of flow reattachment based on the selective reflection properties of shear sensitive crystals was achieved only marginally because of the larger surface shear stress and shear stress gradient levels required for more dramatic color differences.

Building a road map for tailoring multilayer polyelectrolyte films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ankner, John Francis; Bardoel, Agatha A; Sukishvili, Svetlana

2012-01-01

Researchers are moving a step closer to a definite road map for building layer-by-layer (LbL) assembled polyelectrolyte films, with the assistance of the Liquids Reflectometer at Oak Ridge National Laboratory's Spallation Neutron Source, in Oak Ridge, Tennessee. Scientists using the liquids reflectometer have successfully taken snapshots in close to real time of these multilayered structures for different applications when they modify the structure and function parameters. Polyelecrolytes are polymers that carry charge in aqueous solutions. They contain chemical groups that dissociate in water, making such polymers charged. Most polyelectrolytes are water soluble. They are important components in foods, soaps, shampoos,more » and cosmetics products. They show promise for such environmental work as oil recovery and water treatment. Polyelectrolytes are compelling because researchers can chemically modify how they interact with water for multiple applications. When two types of polyelectrolytes of opposite charge are assembled at a surface in a sequential way using the LbL assembly technique, 'the result is the forming of surface films, useful for coatings, biomedical implants and devices, controlling adhesion of biological molecules, and controlling delivery of therapeutic molecules from surfaces,' said Svetlana Sukhishvili of the Stevens Institute of Technology in New Jersey, the lead chemist on the collaboration. 'Medical doctors often prefer to deliver multiple therapeutic compounds from the coatings in a time-resolved manner,' Sukhishvili said. 'To assist them, material scientists need to learn how to build coatings in which polymer layering will not be compromised when exposed to normal physiological conditions.' 'Being able to control these properties, understanding how what you do to the materials affects their properties, this allows you to apply them to situations where interacting with an environment is very helpful, whether in a biological context or any other kind of water soluble context,' said John Ankner, lead instrument scientist for the Liquids Reflectometer. Ankner said that when several parameters are systematically altered, that allows researchers to map out the whole range of structures in the polymer. 'This work really sets a road map for how to get started with synthesizing polyelectrolyte materials for specific applications. Then, one can say, ok, this methylated material, the one that is 30% charged, is going to be what we want to use for a particular application.' The ORNL collaboration with the Stevens Institute has been conducting a series of experiments at the SNS to study layered film stratification in these polymers. Researchers stitch the polyelectrolyte chains in the LbL films together through what is called ionic pairing and arrange them within fuzzy, ultrathin layers that lie parallel to a solid surface substrate. Exposure of these films to aqueous solutions that contain salt (i.e., conditions that imitate real life) can compromise this film layering, as the salt ions act to weaken the ionic pairing that binds such layers together. So salt solutions are of key interest in studying how to make such layers for use in human applications. In the first research, Ankner, Sukhishvili and her student Li Xu looked at the effects of the layering of two types of LbL films of changing the charge density with a salt solution, and of blocking access to a charged site by nearby groups. The films were composed of positively charged variants of PDMA, a methyl polymer, and PDEA, an ethyl polymer. The other component of both systems is the ion exchanger polystyrene sulfonate (PSS) which features a fixed negative charge. First, a silicon substrate was dipped into solutions of PDMA and PDEA in dilute sodium chloride for a fixed time. Depending on the deposition time and the concentration of the solution, a nanometer-thick monolayer of the polymer adsorbs to the silicon surface. The film buildup is then continued by depositing a layer of PSS, and the cycle is repeated. The PDMA (methyl)/PSS and PDEA (ethyl)/PSS films were then annealed in varying concentrations of aqueous salt solutions. The chemists wanted to know if in these multi-layer cake-like assemblies, the structure can be systematically altered by varying the salt concentration, time in solution, and ultimately other environmental parameters, such as temperature or pH. Neutron reflectivity of the layered films exhibits the quality of the layering, in particular the concentration of the layers and how intermixed they are with adjacent layers. In this research, neutron reflectivity data from films built from 10%, 40%, and 100% charged PDMA or PDEA polyelectrolytes and 100% charged PSS were quantitatively compared to predicted, layered arrangements until the models produced reflectivity patterns matching those of the data.« less

In vitro antioxidant activity and inhibitory effect, on oleic acid-induced hepatic steatosis, of fractions and subfractions from oat (Avena sativa L.) ethanol extract

USDA-ARS?s Scientific Manuscript database

Oats (Avena sativa L.) were extracted with 80% aqueous ethanol and the extract was successively isolated by liquid-liquid partition to yield n-hexane, ethyl acetate, n-butanol and water layers. Among these extractions the ethyl acetate (EA) layer exhibited the highest total phenolic content (TPC), t...

Liquid Crystals

NASA Technical Reports Server (NTRS)

1990-01-01

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

Double layer effects on metal nucleation in deep eutectic solvents.

PubMed

Abbott, Andrew P; Barron, John C; Frisch, Gero; Gurman, Stephen; Ryder, Karl S; Fernando Silva, A

2011-06-07

The electrodeposition of zinc has been studied in two deep eutectic solvents. Unlike the metals studied to date in these liquids, zinc electrodeposition is not mass transport limited and the morphology of the deposit differs in the two liquids. This study shows that changing the concentration of solute affects the physical properties of the liquid to different extents although this is found to not effect the morphology of the metal deposited. EXAFS was used to show that the speciation of zinc was the same in both liquids. Double layer capacitance studies showed differences between the two liquids and these are proposed to be due to the adsorption of a species on the electrode which is thought to be chloride. The differences in zinc morphology is attributed to blocking of certain crystal faces leading to deposition of small platelet shaped crystals in the glycol based liquid.

Microstructural Development during Directional Solidification of Peritectic Alloys

NASA Technical Reports Server (NTRS)

Lograsso, Thomas A.

1996-01-01

A thorough understanding of the microstructures produced through solidification in peritectic systems has yet to be achieved, even though a large number of industrially and scientifically significant materials are in this class. One type of microstructure frequently observed during directional solidification consists of alternating layers of primary solid and peritectic solid oriented perpendicular to the growth direction. This layer formation is usually reported for alloy compositions within the two-phase region of the peritectic isotherm and for temperature gradient and growth rate conditions that result in a planar solid-liquid interface. Layered growth in peritectic alloys has not previously been characterized on a quantitative basis, nor has a mechanism for its formation been verified. The mechanisms that have been proposed for layer formation can be categorized as either extrinsic or intrinsic to the alloy system. The extrinsic mechanisms rely on externally induced perturbations to the system for layer formation, such as temperature oscillations, growth velocity variations, or vibrations. The intrinsic mechanisms approach layer formation as an alternative type of two phase growth that is inherent for certain peritectic systems and solidification conditions. Convective mixing of the liquid is an additional variable which can strongly influence the development and appearance of layers due to the requisite slow growth rate. The first quantitative description of layer formation is a model recently developed by Trivedi based on the intrinsic mechanism of cyclic accumulation and depiction of solute in the liquid ahead of the interface, linked to repeated nucleation events in the absence of convection. The objective of this research is to characterize the layered microstructures developed during ground-based experiments in which external influences have been minimized as much as possible and to compare these results to the current the model. Also, the differences between intrinsic and externally influenced layer formation were explored. The choice of alloy system is critical to a study of the formation of layered microstructures. The ideal system would have a well-characterized phase diagram, equal densities of both elements in the liquid state to minimize compositionally-driven convective flows, a low peritectic temperature to simplify directional solidification and the achievement of a high temperature gradient in the liquid, a broad composition range for the peritectic reaction, and a reasonable hardness at room temperature to facilitate handling and metallographic preparation. The In-Sn system was selected initially due to a very low peritectic temperature and the nearly equal densities of In and Sn in the liquid state. Since the In-rich peritectic reaction had apparently not been utilized previously for solidification research, experiments were conducted to check the phase diagram in the region of interest. The alloys in this system proved to be difficult to handle and prepare in bulk form with the equipment available, so experiments were initiated with the Sn-Cd system. Layered microstructures had been observed previously in Sn-Cd.

Ignition of deuterium-trtium fuel targets

DOEpatents

Musinski, Donald L.; Mruzek, Michael T.

1991-01-01

A method of igniting a deuterium-tritium ICF fuel target to obtain fuel burn in which the fuel target initially includes a hollow spherical shell having a frozen layer of DT material at substantially uniform thickness and cryogenic temperature around the interior surface of the shell. The target is permitted to free-fall through a target chamber having walls heated by successive target ignitions, so that the target is uniformly heated during free-fall to at least partially melt the frozen fuel layer and form a liquid single-phase layer or a mixed liquid/solid bi-phase layer of substantially uniform thickness around the interior shell surface. The falling target is then illuminated from exteriorly of the chamber while the fuel layer is at substantially uniformly single or bi-phase so as to ignite the fuel layer and release energy therefrom.

Ignition of deuterium-tritium fuel targets

DOEpatents

Musinski, D.L.; Mruzek, M.T.

1991-08-27

Disclosed is a method of igniting a deuterium-tritium ICF fuel target to obtain fuel burn in which the fuel target initially includes a hollow spherical shell having a frozen layer of DT material at substantially uniform thickness and cryogenic temperature around the interior surface of the shell. The target is permitted to free-fall through a target chamber having walls heated by successive target ignitions, so that the target is uniformly heated during free-fall to at least partially melt the frozen fuel layer and form a liquid single-phase layer or a mixed liquid/solid bi-phase layer of substantially uniform thickness around the interior shell surface. The falling target is then illuminated from exteriorly of the chamber while the fuel layer is at substantially uniformly single or bi-phase so as to ignite the fuel layer and release energy therefrom. 5 figures.

Water at silica/liquid water interfaces investigated by DFT-MD simulations

NASA Astrophysics Data System (ADS)

Gaigeot, Marie-Pierre

This talk is dedicated to probing the microscopic structural organization of water at silica/liquid water interfaces including electrolytes by first principles DFT-based molecular dynamics simulations (DFT-MD). We will present our very recent DFT-MD simulations of electrolytic (KCl, NaCl, NaI) silica/liquid water interfaces in order to unravel the intertwined structural properties of water and electrolytes at the crystalline quartz/liquid water and amorphous silica/liquid water interfaces. DFT-MD simulations provide direct knowledge of the structural organization of water and the H-Bond network formed between the water molecules within the different water layers above the silica surface. One can furthermore extract vibrational signatures of the water molecules within the interfacial layers from the DFT-MD simulations, especially non-linear SFG (Sum Frequency generation) signatures that are active at solid/liquid interfaces. The strength of the simulated spectra is that a detailed analysis of the signatures in terms of the water/water H-Bond networks formed within the interfacial water layers and in terms of the water/silica or water/electrolytes H-Bond networks can be given. Comparisons of SFG spectra between quartz/water/electrolytes and amorphous silica/water/electrolytes interfaces allow us to definitely conclude on how the structural arrangements of liquid water at these electrolytic interfaces modulate the final spectroscopic signatures. Invited speaker.

Turbine vane structure

DOEpatents

Irwin, John A.

1980-08-19

A liquid cooled stator blade assembly for a gas turbine engine includes an outer shroud having a pair of liquid inlets and a pair of liquid outlets supplied through a header and wherein means including tubes support the header radially outwardly of the shroud and also couple the header with the pair of liquid inlets and outlets. A pair of turbine vanes extend radially between the shroud and a vane platform to define a gas turbine motive fluid passage therebetween; and each of the vanes is cooled by an internal body casting of super alloy material with a grooved layer of highly heat conductive material that includes spaced apart flat surface trailing edges in alignment with a flat trailing edge of the casting joined to wall segments of the liner which are juxtaposed with respect to the internal casting to form an array of parallel liquid inlet passages on one side of the vane and a second plurality of parallel liquid return passages on the opposite side of the vane; and a superalloy heat and wear resistant imperforate skin covers the outer surface of the composite blade including the internal casting and the heat conductive layer; a separate trailing edge section includes an internal casting and an outer skin butt connected to the end surfaces of the internal casting and the heat conductive layer to form an easily assembled liquid cooled trailing edge section in the turbine vane.

PRODUCTION OF FLUOROCARBONS

DOEpatents

Sarsfield, N.F.

1949-06-21

This patent pertains to a process for recovering fluorocarbons from a liquid mixture of hydrocarbons with partially and completely fluorinated products thereof. It consists of contacting the mxture in the cold with a liquid which is a solvent for the hydrocarbons and which is a nonsolvent for the fluorocarbons, extracting the hydrocarbons, separating the fluorocarbon-containing layer from the solvent-containing layer, and submitting the fluorocarbon layer to fractlonal distillation, to isolate the desired fluorocarbon fraction. Suitable solvents wnich may be used in the process include the lower aliphatic alcohols, and the lower aliphatic ketones.

REACTOR FUEL SCAVENGING MEANS

DOEpatents

Coffinberry, A.S.

1962-04-10

A process for removing fission products from reactor liquid fuel without interfering with the reactor's normal operation or causing a significant change in its fuel composition is described. The process consists of mixing a liquid scavenger alloy composed of about 44 at.% plutoniunm, 33 at.% lanthanum, and 23 at.% nickel or cobalt with a plutonium alloy reactor fuel containing about 3 at.% lanthanum; removing a portion of the fuel and scavenger alloy from the reactor core and replacing it with an equal amount of the fresh scavenger alloy; transferring the portion to a quiescent zone where the scavenger and the plutonium fuel form two distinct liquid layers with the fission products being dissolved in the lanthanum-rich scavenger layer; and the clean plutonium-rich fuel layer being returned to the reactor core. (AEC)

Methods of producing armor systems, and armor systems produced using such methods

DOEpatents

Chu, Henry S; Lillo, Thomas M; McHugh, Kevin M

2013-02-19

An armor system and method involves providing a core material and a stream of atomized coating material that comprises a liquid fraction and a solid fraction. An initial layer is deposited on the core material by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is less than the liquid fraction of the stream of atomized coating material on a weight basis. An outer layer is then deposited on the initial layer by positioning the core material in the stream of atomized coating material wherein the solid fraction of the stream of atomized coating material is greater than the liquid fraction of the stream of atomized coating material on a weight basis.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Strelcov, Evgheni; Cothren, Joshua E.; Leonard, Donovan N.

Progress in rational engineering of Li-ion batteries requires better understanding of the electrochemical processes and accompanying transformations in the electrode materials on multiple length scales. In spite of recent progress in utilizing transmission electron microscopy (TEM) to analyze these materials, in situ scanning electron microscopy (SEM) was mostly overlooked as a powerful tool that allows probing these phenomena on the nano and mesoscale. In this paper, we report on in situ SEM study of lithiation in a V 2O 5-based single-nanobelt battery with ionic liquid electrolyte. Coupled with cyclic voltammetry measurements, in situ SEM revealed the peculiarities of subsurface intercalation,more » formation of solid-electrolyte interface (SEI) and electromigration of liquid. We observed that single-crystalline vanadia nanobelts do not undergo large-scale amorphization or fracture during electrochemical cycling, but rather transform topochemically with only a slight shape distortion. Lastly, the SEI layer seems to have significant influence on the lithium ion diffusion and overall capacity of the single-nanobelt battery.« less

A case study of microphysical structures and hydrometeor phase in convection using radar Doppler spectra at Darwin, Australia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riihimaki, Laura D.; Comstock, Jennifer M.; Luke, Edward

To understand the microphysical processes that impact diabatic heating and cloud lifetimes in convection, we need to characterize the spatial distribution of supercooled liquid water. To address this observational challenge, vertically pointing active sensors at the Darwin Atmospheric Radiation Measurement (ARM) site are used to classify cloud phase within a deep convective cloud in a shallow to deep convection transitional case. The cloud cannot be fully observed by a lidar due to signal attenuation. Thus we develop an objective method for identifying hydrometeor classes, including mixed-phase conditions, using k-means clustering on parameters that describe the shape of the Doppler spectramore » from vertically pointing Ka band cloud radar. This approach shows that multiple, overlapping mixed-phase layers exist within the cloud, rather than a single region of supercooled liquid, indicating complexity to how ice growth and diabatic heating occurs in the vertical structure of the cloud.« less

A case study of microphysical structures and hydrometeor phase in convection using radar Doppler spectra at Darwin, Australia

DOE PAGES

Riihimaki, Laura D.; Comstock, J. M.; Luke, E.; ...

2017-07-12

To understand the microphysical processes that impact diabatic heating and cloud lifetimes in convection, we need to characterize the spatial distribution of supercooled liquid water. To address this observational challenge, ground-based vertically pointing active sensors at the Darwin Atmospheric Radiation Measurement site are used to classify cloud phase within a deep convective cloud. The cloud cannot be fully observed by a lidar due to signal attenuation. Therefore, we developed an objective method for identifying hydrometeor classes, including mixed-phase conditions, using k-means clustering on parameters that describe the shape of the Doppler spectra from vertically pointing Ka-band cloud radar. Furthermore, thismore » approach shows that multiple, overlapping mixed-phase layers exist within the cloud, rather than a single region of supercooled liquid. Diffusional growth calculations show that the conditions for the Wegener-Bergeron-Findeisen process exist within one of these mixed-phase microstructures.« less

A case study of microphysical structures and hydrometeor phase in convection using radar Doppler spectra at Darwin, Australia

DOE Office of Scientific and Technical Information (OSTI.GOV)

Riihimaki, Laura D.; Comstock, J. M.; Luke, E.

To understand the microphysical processes that impact diabatic heating and cloud lifetimes in convection, we need to characterize the spatial distribution of supercooled liquid water. To address this observational challenge, ground-based vertically pointing active sensors at the Darwin Atmospheric Radiation Measurement site are used to classify cloud phase within a deep convective cloud. The cloud cannot be fully observed by a lidar due to signal attenuation. Therefore, we developed an objective method for identifying hydrometeor classes, including mixed-phase conditions, using k-means clustering on parameters that describe the shape of the Doppler spectra from vertically pointing Ka-band cloud radar. Furthermore, thismore » approach shows that multiple, overlapping mixed-phase layers exist within the cloud, rather than a single region of supercooled liquid. Diffusional growth calculations show that the conditions for the Wegener-Bergeron-Findeisen process exist within one of these mixed-phase microstructures.« less

A new hue capturing technique for the quantitative interpretation of liquid crystal images used in convective heat transfer studies

NASA Technical Reports Server (NTRS)

Camci, C.; Kim, K.; Hippensteele, S. A.

1992-01-01

A new image processing based color capturing technique for the quantitative interpretation of liquid crystal images used in convective heat transfer studies is presented. This method is highly applicable to the surfaces exposed to convective heating in gas turbine engines. It is shown that, in the single-crystal mode, many of the colors appearing on the heat transfer surface correlate strongly with the local temperature. A very accurate quantitative approach using an experimentally determined linear hue vs temperature relation is found to be possible. The new hue-capturing process is discussed in terms of the strength of the light source illuminating the heat transfer surface, the effect of the orientation of the illuminating source with respect to the surface, crystal layer uniformity, and the repeatability of the process. The present method is more advantageous than the multiple filter method because of its ability to generate many isotherms simultaneously from a single-crystal image at a high resolution in a very time-efficient manner.

Atomic study on the ordered structure in Al melts induced by liquid/substrate interface with Ti solute

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zhang, H. L.; Han, Y. F., E-mail: yfhan@sjtu.edu.cn, E-mail: bdsun@sjtu.edu.cn; Zhou, W.

2015-01-26

Atomic ordering in Al melts induced by liquid/substrate interface with Ti solute was investigated by ab initio molecular dynamics simulations and in-situ synchrotron X-ray diffraction. It is predicted that deformed nanoscale ordering Al layers with a rhombohedral-centered hexagonal structure (R3{sup ¯}m space group) instead of the intrinsic fcc structure (Fm3{sup ¯}m space group) form on substrate at temperature above Al liquids. With Al atoms stacking away from the interface, the ordering structure reaches a critical thickness, which inhibits the consecutive stacking of Al atoms on substrates. The locally stacking reconstruction induced by Ti atom relieves the accumulated elastic strain energymore » in ordered Al layers, facilitating fully heterogeneous nucleation on substrate beyond the deformed ordering Al layer around the melting point. The roles of liquid/substrate interface with Ti solute in the physical behavior of heterogeneous nucleation on substrate were discussed.« less

Non-isothermal two-phase transport in the polymer electrolyte membrane fuel cell microporous layer

NASA Astrophysics Data System (ADS)

Ge, Nan

This thesis investigates the water transport mechanisms in the crack-free microporous layer (MPL) of a polymer electrolyte membrane (PEM) fuel cell. Synchrotron X-ray radiography was used to visualize and quantify the in situ liquid water in the gas diffusion layers (GDLs) of an operating fuel cell. A methodology was developed to correct the artefact of imaging sample movement. Furthermore, to address inaccuracies due to the scattering effect and higher harmonics at the synchrotron beamline, a calibration technique was introduced in order to experimentally determine the liquid water X-ray attenuation coefficient. Through in situ radiography, liquid water breakthrough events were observed in the MPL, and measured water thicknesses were used as inputs into a one-dimensional (1D) heat and mass transport model. The 1D model was used to describe the coupled relationship between liquid and vapour transport through the cathode MPL and the temperature distributions in the operating fuel cell.

Presumption of large-scale heterogeneity at the top of the outer core basal layer

NASA Astrophysics Data System (ADS)

Souriau, Annie

2015-04-01

A layer of reduced P-velocity gradient with thickness of about 100-200 km has been identified at the base of the liquid core from seismological methods. It has been interpreted as a dense layer resulting from partial re-melting of the inner core, which is depleted in light elements with respect to the liquid core during freezing. In an attempt to specify where freezing and re-melting occur, the structure of this basal layer is investigated with the seismological core phase PKPbc which has its turning point in the lower third of the outer core. The large PKPbc data set of the EHB catalog distributed by the International Seismological Centre is analyzed. In order to compensate for the uneven distribution of the data and to minimize the influence of mantle heterogeneities, the travel time anomalies are binned inside equal area and equal azimuth sectors sampling the base of the liquid core at different depths. Most of the observed variations in the binned travel time residuals are not significant according to their confidence level. The only features which could be significant are a large patch with a velocity increase of about 0.5% located at the top of the basal layer beneath the eastern hemisphere, and the complementary velocity decrease beneath the western hemisphere and the South pole. This observation suggests that some freezing or re-melting processes occur at the top of the basal layer with a hemispherical dissymmetry. If confirmed, it may give strong constraints on the fate of the light elements during the freezing and re-melting process and on their interaction with the basal layer and the overlying liquid core.

Fabrication of hemispherical liquid encapsulated structures based on droplet molding

NASA Astrophysics Data System (ADS)

Ishizuka, Hiroki; Miki, Norihisa

2015-12-01

We have developed and demonstrated a method for forming spherical structures of a thin polydimethylsiloxane (PDMS) membrane encapsulating a liquid. Liquid encapsulation can enhance the performance of microelectromechanical systems (MEMS) devices by providing deformability and improved dielectric properties. Parylene deposition and wafer bonding are applied to encapsulate liquid into a MEMS device. In parylene deposition, a parylene membrane is directly formed onto a liquid droplet. However, since the parylene membrane is stiff, the membrane is fragile. Although wafer bonding can encapsulate liquid between two substrates, the surface of the fabricated structure is normally flat. We propose a new liquid encapsulation method by dispensing liquid droplets. At first, a 20 μl PDMS droplet is dispensed on ethylene glycol. A 70 μl glycerin droplet is dispensed into a PDMS casting solution layer. The droplet forms a layer on heated ethylene glycol. Glycerin and ethylene glycol are chosen for their high boiling points. Additionally, a glycerin droplet is dispensed on the layer and surrounded by a thin PDMS casting solution film. The film is baked for 1 h at 75 °C. As the result, a structure encapsulating a liquid in a flexible PDMS membrane is obtained. We investigate the effects of the volume, surface tension, and guide thickness on the shape of the formed structures. We also evaluated the effect of the structure diameter on miniaturization. The structure can be adapted for various functions by changing the encapsulated liquid. We fabricated a stiffness-tunable structure by dispensing a magnetorheoligical fluid droplet with a stiffness that can be changed by an external magnetic field. We also confirmed that the proposed structure can produce stiffness differences that are distinguishable by humans.

Nanocuvette: A Functional Ultrathin Liquid Container for Transmission Electron Microscopy.

PubMed

Wadell, Carl; Inagaki, Satoshi; Nakamura, Tomiro; Shi, Ji; Nakamura, Yoshio; Sannomiya, Takumi

2017-02-28

Advances in TEM techniques have spurred a renewed interest in a wide variety of research fields. A rather recent track within these endeavors is the use of TEM for in situ imaging in liquids. In this article, we show the fabrication of a liquid cell for TEM observations which we call the nanocuvette. The structure consists of a nanohole film sandwiched by carbon films, sealing liquid in the holes. The hole film can be produced using a variety of materials, tailored for the desired application. Since the fabrication is based on self-assembly, it is both cheap and straightforward. Compared to previously reported liquid cells, this structure allows for thinner liquid layers with better controlled cell structures, making it possible to achieve a high resolution even at lower acceleration voltages and electron doses. We demonstrate a resolution corresponding to an information transfer up to ∼2 nm at 100 kV for molecular imaging. Apart from the advantages arising from the thin liquid layer, the nanocuvette also enables the possibility to study liquid-solid interfaces at the side walls of the nanoholes. We illustrate the possibilities of the nanocuvette by studying several model systems: electron beam induced growth dynamics of silver nanoparticles in salt solution, polymer deposition from solution, and imaging of nonstained antibodies in solution. Finally, we show how the inclusion of a plasmonically active gold layer in the nanocuvette structure enables optical confirmation of successful liquid encapsulation prior to TEM studies. The nanocuvette provides an easily fabricated and flexible platform which can help further the understanding of reactions, processes, and conformation of molecules and atoms in liquid environments.

Layer-by-layer assembled biopolymer microcapsule with separate layer cavities generated by gas-liquid microfluidic approach.

PubMed

Wang, Yifeng; Zhou, Jing; Guo, Xuecheng; Hu, Qian; Qin, Chaoran; Liu, Hui; Dong, Meng; Chen, Yanjun

2017-12-01

In this work, a layer-by-layer (LbL) assembled biopolymer microcapsule with separate layer cavities is generated by a novel and convenient gas-liquid microfluidic approach. This approach exhibits combined advantages of microfluidic approach and LbL assembly method, and it can straightforwardly build LbL-assembled capsules in mild aqueous environments at room temperature. In particular, using this approach we can build the polyelectrolyte multilayer capsule with favorable cavities in each layer, and without the need for organic solvent, emulsifying agent, or sacrificial template. Various components (e.g., drugs, proteins, fluorescent dyes, and nanoparticles) can be respectively encapsulated in the separate layer cavities of the LbL-assembled capsules. Moreover, the encapsulated capsules present the ability as colorimetric sensors, and they also exhibit the interesting release behavior. Therefore, the LbL-assembled biopolymer capsule is a promising candidate for biomedical applications in targeted delivery, controlled release, and bio-detection. Copyright © 2017 Elsevier B.V. All rights reserved.

DNSs of Multicomponent Gaseous and Drop-Laden Mixing Layers Achieving Transition to Turbulence

NASA Technical Reports Server (NTRS)

Bellan, Josette; Selle, Laurent

2007-01-01

A paper describes direct numerical simulations (DNSs) of three-dimensional mixing-layer flows undergoing transition to turbulence; the mixing layers may or may not be laden with evaporating liquid drops.

Immiscible Systems

ERIC Educational Resources Information Center

Eckelmann, Jens; Luning, Ulrich

2013-01-01

layers of liquids. The setup of both demonstrations is such that one homogeneous layer in a multiphasic mixture separates into two new layers upon shaking. The solvents used are methanol, toluene, petroleum ether or "n"-pentane, silicone oil, perfluoroheptanes,…

Ultrahigh-throughput exfoliation of graphite into pristine 'single-layer' graphene using microwaves and molecularly engineered ionic liquids.

PubMed

Matsumoto, Michio; Saito, Yusuke; Park, Chiyoung; Fukushima, Takanori; Aida, Takuzo

2015-09-01

Graphene has shown much promise as an organic electronic material but, despite recent achievements in the production of few-layer graphene, the quantitative exfoliation of graphite into pristine single-layer graphene has remained one of the main challenges in developing practical devices. Recently, reduced graphene oxide has been recognized as a non-feasible alternative to graphene owing to variable defect types and levels, and attention is turning towards reliable methods for the high-throughput exfoliation of graphite. Here we report that microwave irradiation of graphite suspended in molecularly engineered oligomeric ionic liquids allows for ultrahigh-efficiency exfoliation (93% yield) with a high selectivity (95%) towards 'single-layer' graphene (that is, with thicknesses <1 nm) in a short processing time (30 minutes). The isolated graphene sheets show negligible structural deterioration. They are also readily redispersible in oligomeric ionic liquids up to ~100 mg ml(-1), and form physical gels in which an anisotropic orientation of graphene sheets, once induced by a magnetic field, is maintained.

Transition from Selective Withdrawal to Light Layer Entrainment in an Oil-Water System

NASA Astrophysics Data System (ADS)

Hartenberger, Joel; O'Hern, Timothy; Webb, Stephen; James, Darryl

2010-11-01

Selective withdrawal refers to the selective removal of fluid of one density without entraining an adjacent fluid layer of a different density. Most prior literature has examined removal of the lower density fluid and the transition to entraining the higher density fluid. In the present experiments, a higher density liquid is removed through a tube that extends just below its interface with a lower density fluid. The critical depth for a given flow rate at which the liquid-liquid interface transitions to entrain the lighter fluid was measured. Experiments were performed for a range of different light layer silicone oils and heavy layer water or brine, covering a range of density and viscosity ratios. Applications include density-stratified reservoirs and brine removal from oil storage caverns. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

Three-dimensional MHD (magnetohydrodynamic) flows in rectangular ducts of liquid-metal-cooled blankets

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hua, T.Q.; Walker, J.S.; Picologlou, B.F.

1988-07-01

Magnetohydrodynamic flows of liquid metals in rectangular ducts with thin conducting walls in the presence of strong nonuniform transverse magnetic fields are examined. The interaction parameter and Hartmann number are assumed to be large, whereas the magnetic Reynolds number is assumed to be small. Under these assumptions, viscous and inertial effects are confined in very thin boundary layers adjacent to the walls. A significant fraction of the fluid flow is concentrated in the boundary layers adjacent to the side walls which are parallel to the magnetic field. This paper describes the analysis and numerical methods for obtaining 3-D solutions formore » flow parameters outside these layers, without solving explicitly for the layers themselves. Numerical solutions are presented for cases which are relevant to the flows of liquid metals in fusion reactor blankets. Experimental results obtained from the ALEX experiments at Argonne National Laboratory are used to validate the numerical code. In general, the agreement is excellent. 5 refs., 14 figs.« less

Airfoil deposition model

NASA Technical Reports Server (NTRS)

Kohl, F. J.

1982-01-01

The methodology to predict deposit evolution (deposition rate and subsequent flow of liquid deposits) as a function of fuel and air impurity content and relevant aerodynamic parameters for turbine airfoils is developed in this research. The spectrum of deposition conditions encountered in gas turbine operations includes the mechanisms of vapor deposition, small particle deposition with thermophoresis, and larger particle deposition with inertial effects. The focus is on using a simplified version of the comprehensive multicomponent vapor diffusion formalism to make deposition predictions for: (1) simple geometry collectors; and (2) gas turbine blade shapes, including both developing laminar and turbulent boundary layers. For the gas turbine blade the insights developed in previous programs are being combined with heat and mass transfer coefficient calculations using the STAN 5 boundary layer code to predict vapor deposition rates and corresponding liquid layer thicknesses on turbine blades. A computer program is being written which utilizes the local values of the calculated deposition rate and skin friction to calculate the increment in liquid condensate layer growth along a collector surface.

Successive reactive liquid flow episodes in a layered intrusion (Unit 9, Rum Eastern Layered Intrusion, Scotland)

NASA Astrophysics Data System (ADS)

Leuthold, Julien; Blundy, Jon; Holness, Marian

2014-05-01

We will present a detailed microstructural and geochemical study of reactive liquid flow in Unit 9 of the Rum Eastern Layered Intrusion. In the study region, Unit 9 comprises an underlying lens-like body of peridotite overlain by a sequence of troctolite and gabbro (termed allivalite), with some local and minor anorthosite. The troctolite is separated from the overlying gabbro by a distinct, sub-horizontal, undulose horizon (the major wavy horizon). Higher in the stratigraphy is another, similar, horizon (the minor wavy horizon) that separates relatively clinopyroxene-poor gabbro from an overlying gabbro. To the north of the peridotite lens, both troctolite and gabbro grade into poikilitic gabbro. Clinopyroxene habit in the allivalite varies from thin rims around olivine in troctolite, to equigranular crystals in gabbro, to oikocrysts in the poikilitic gabbro. The poikilitic gabbros contain multiple generations of clinopyroxene, with Cr-rich (~1.1 wt.% Cr2O3), anhedral cores with moderate REE concentrations (core1) overgrown by an anhedral REE-depleted second generation with moderate Cr (~0.7 wt.% Cr2O3) (core2). These composite cores are rimmed by Cr-poor (~0.2 wt.% Cr2O3) and REE-poor to moderate clinopyroxene. We interpret these microstructures as a consequence of two separate episodes of partial melting triggered by the intrusion of hot olivine-phyric picrite to form the discontinuous lenses that comprise the Unit 9 peridotite. Loss of clinopyroxene-saturated partial melt from the lower part of the allivalite immediately following the early stages of sill intrusion resulted in the formation of clinopyroxene-poor gabbro. The spatial extent of clinopyroxene loss is marked by the minor wavy horizon. A further partial melting event stripped out almost all clinopyroxene from the lowest allivalite, to form a troctolite, with the major wavy horizon marking the extent of melting during this second episode. The poikilitic gabbro formed from clinopyroxene-saturated melt moving upwards and laterally through the cumulate pile. The Rum layered intrusion is an open intrusive complex, composed of individual partially molten zones, evolving independently. The Rum layered intrusion offers a direct overview of processes taking place in shallow intra-plate and ridge magma chambers. Intrusion of hot magma into a pre-existing cumulate pile results in the modification both the incoming liquid and the host-rock cumulates. Our study highlights the necessity of considering this type of process when modelling the geochemistry of lavas erupted from magma chambers subject to repeated replenishment.

Quantitative analysis of psilocybin and psilocin in psilocybe baeocystis (Singer and Smith) by high-performance liquid chromatography and by thin-layer chromatography.

PubMed

Beug, M W; Bigwood, J

1981-03-27

Rapid quantification of psilocybin and psilocin in extracts of wild mushrooms is accomplished by reversed-phase high-performance liquid chromatography with paired-ion reagents. Nine solvent systems and three solid supports are evaluated for their efficiency in separating psilocybin, psilocin and other components of crude mushroom extracts by thin-layer chromatography.

Water drop dynamics on a granular layer

NASA Astrophysics Data System (ADS)

Llorens, Coraline; Biance, Anne-Laure; Ybert, Christophe; Pirat, Christophe; Liquids; Interfaces Team

2015-11-01

Liquid drop impacts, either on a solid surface or a liquid bath, have been studied for a while and are still subject of intense research. Less is known concerning impacts on granular layers that are shown to exhibit an intermediate situation between solid and liquid. In this study, we focus on water drop impacts on granular matter made of micrometer-sized spherical glass beads. In particular, we investigate the overall dynamics arising from the interplay between liquid and grains throughout the impact. Depending on the relevant parameters (impact velocity, drop and grain sizes, as well as their wetting properties), various behaviors are evidenced. In particular, the behavior of the beads at the liquid-gas interface (ball-bearing vs imbibition) is shown to greatly affect the spreading dynamics of the drop, as well as satellite droplets formation, beads ejection, and the final crater morphology.

Polyelectrolyte and carbon nanotube multilayers made from ionic liquid solutions

NASA Astrophysics Data System (ADS)

Nakashima, Takuya; Zhu, Jian; Qin, Ming; Ho, Szushen; Kotov, Nicholas A.

2010-10-01

The inevitable contact of substrates with water during the traditional practice of layer-by-layer assembly (LBL) creates problems for multiple potential applications of LBL films in electronics. To resolve this issue, we demonstrate here the possibility of a LBL process using ionic liquids (ILs), which potentially eliminates corrosion and hydration processes related to aqueous media and opens additional possibilities in structural control of LBL films. ILs are also considered to be one of the best ``green'' processing solvents, and hence, are advantageous in respect to traditional organic solvents. Poly(ethyleneimine) (PEI) and poly(sodium styrenesulfonate) (PSS) were dispersed in a hydrophilic IL and successfully deposited in the LBL fashion. To produce electroactive thin films with significance to electronics, a similar process was realized for PSS-modified single-walled carbon nanotubes (SWNT-PSS) and poly(vinyl alcohol) (PVA). Characterization of the coating using standard spectroscopy and microscopy techniques typical of the multilayer field indicated that there are both similarities and differences in the structure and properties of LBL films build from ILs and aqueous solutions. The films exhibited electrical conductivity of 102 S m-1 with transparency as high as 98% for visible light, which is comparable to similar parameters for many carbon nanotube and graphene films prepared by both aqueous LBL and other methods.The inevitable contact of substrates with water during the traditional practice of layer-by-layer assembly (LBL) creates problems for multiple potential applications of LBL films in electronics. To resolve this issue, we demonstrate here the possibility of a LBL process using ionic liquids (ILs), which potentially eliminates corrosion and hydration processes related to aqueous media and opens additional possibilities in structural control of LBL films. ILs are also considered to be one of the best ``green'' processing solvents, and hence, are advantageous in respect to traditional organic solvents. Poly(ethyleneimine) (PEI) and poly(sodium styrenesulfonate) (PSS) were dispersed in a hydrophilic IL and successfully deposited in the LBL fashion. To produce electroactive thin films with significance to electronics, a similar process was realized for PSS-modified single-walled carbon nanotubes (SWNT-PSS) and poly(vinyl alcohol) (PVA). Characterization of the coating using standard spectroscopy and microscopy techniques typical of the multilayer field indicated that there are both similarities and differences in the structure and properties of LBL films build from ILs and aqueous solutions. The films exhibited electrical conductivity of 102 S m-1 with transparency as high as 98% for visible light, which is comparable to similar parameters for many carbon nanotube and graphene films prepared by both aqueous LBL and other methods. Electronic supplementary information (ESI) available: Aggregation of PEI and PSS in [EMIm][EtSO4], detailed FTIR data, water-contact angle for (PEI/PSS)10 multilayers, and XPS survey spectra. See DOI: 10.1039/b9nr00333a

Selenium Interlayer for High-Efficiency Multijunction Solar Cell

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A (Inventor)

2015-01-01

A multi junction solar cell is provided and includes multiple semiconducting layers and an interface layer disposed between the multiple semiconducting layers. The interface layer is made from an interface bonding material that has a refractive index such that a ratio of a refractive index of each of the multiple semiconducting layers to the refractive index of the interface bonding material is less than or equal to 1.5.

Selenium Interlayer for High-Efficiency Multijunction Solar Cell

NASA Technical Reports Server (NTRS)

Landis, Geoffrey A. (Inventor)

2016-01-01

A multi-junction solar cell is provided and includes multiple semiconducting layers and an interface layer disposed between the multiple semiconducting layers. The interface layer is made from an interface bonding material that has a refractive index such that a ratio of a refractive index of each of the multiple semiconducting layers to the refractive index of the interface bonding material is less than or equal to 1.5.

Microfluidic liquid-air dual-gradient chip for synergic effect bio-evaluation of air pollutant.

PubMed

Liu, Xian-Jun; Hu, Shan-Wen; Xu, Bi-Yi; Zhao, Ge; Li, Xiang; Xie, Fu-Wei; Xu, Jing-Juan; Chen, Hong-Yuan

2018-05-15

In this paper, a novel prototype liquid-air dual gradient chip is introduced, which has paved the way for effective synergic effect bio-evaluation of air pollutant. The chip is composed of an array of the agarose liquid-air interfaces, top air gradient layer and bottom liquid gradient layer. The novel agarose liquid-air interface allows for non-biased exposure of cells to all the substances in the air and diffusive interactions with the liquid phase; while the dual liquid-air gradient provides powerful screening abilities, which well reduced errors, saved time and cost from repeated experiment. Coupling the two functions, the chip subsequently facilitates synergic effect evaluation of both liquid and air factors on cells. Here cigarette smoke was taken as the model air pollutant, and its strong synergic effects with inflammatory level of A549 lung cancer cells on their fate were successfully quantified for the first time. These results well testified that the proposed dual-gradient chip is powerful and indispensable for bio-evaluation of air pollutant. Copyright © 2018 Elsevier B.V. All rights reserved.

Damping of liquid sloshing by foams: from everyday observations to liquid transport

NASA Astrophysics Data System (ADS)

Sauret, Alban; Boulogne, Francois; Cappello, Jean; Stone, Howard

2014-11-01

When a liquid-filled container is set in motion, the free surface of the liquid starts to slosh, i.e. oscillate. Such effects can be observed when a glass of water is handled carelessly and the fluid sloshes or even spills over the rim of the container. However, beer does not slosh as readily, which suggests that the presence of foam could be used to damp sloshing. In this work, we study experimentally the effect on sloshing of liquid foam placed on top of a liquid bath in a Hele-Shaw cell. We generate a monodisperse 2D liquid foam and track its motion. The influence of the foam on the sloshing dynamics is characterized: 2 to 3 layers of bubbles are sufficient to significantly damp the oscillations. For more than 5 layers of bubbles, the original vertical motion of the foam becomes mainly horizontal. We rationalize our experimental findings with a model that describes the foam contribution to the damping coefficient. This study motivated by everyday observations has promising applications in numerous industrial applications such as the transport of liquid in cargoes.

Drug Release as a function of bioactivity, incubation regime, liquid, and initial load: Release of bortezomib from calcium phosphate-containing silica/collagen xerogels.

PubMed

Kruppke, Benjamin; Hose, Dirk; Schnettler, Reinhard; Seckinger, Anja; Rößler, Sina; Hanke, Thomas; Heinemann, Sascha

2018-04-01

The ability of silica-/collagen-based composite xerogels to act as drug delivery systems was evaluated by taking into account the initial drug concentration, bioactivity of the xerogels, liquid, and incubation regime. The proteasome inhibitor bortezomib was chosen as a model drug, used for the systemic treatment of multiple myeloma. Incubation during 14 days in phosphate-buffered saline (PBS) or simulated body fluid (SBF) showed a weak initial burst and was identified to be of first order with subsequent release being independent from the initial load of 0.1 or 0.2 mg bortezomib per 60 mg monolithic sample. Faster drug release occurred during incubation in SBF compared to PBS, and during static incubation without changing the liquid, compared to dynamic incubation with daily liquid changes. Drug-loaded xerogels with hydroxyapatite as a third component exhibited enhanced bioactivity retarding drug release, explained by formation of a surface calcium phosphate layer. The fastest release of 50% of the total drug load was observed for biphasic xerogels after 7 days during dynamic incubation in SBF. As a result, the presented concept is suitable for the intended combination of the advantageous bone substitution properties of xerogels and local application of drugs exemplified by bortezomib. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 1165-1173, 2018. © 2017 Wiley Periodicals, Inc.

Impurity effects on ionic-liquid-based supercapacitors

NASA Astrophysics Data System (ADS)

Liu, Kun; Lian, Cheng; Henderson, Douglas; Wu, Jianzhong

2017-02-01

Small amounts of an impurity may affect the key properties of an ionic liquid and such effects can be dramatically amplified when the electrolyte is under confinement. Here the classical density functional theory is employed to investigate the impurity effects on the microscopic structure and the performance of ionic-liquid-based electrical double-layer capacitors, also known as supercapacitors. Using a primitive model for ionic species, we study the effects of an impurity on the double layer structure and the integral capacitance of a room temperature ionic liquid in model electrode pores and find that an impurity strongly binding to the surface of a porous electrode can significantly alter the electric double layer structure and dampen the oscillatory dependence of the capacitance with the pore size of the electrode. Meanwhile, a strong affinity of the impurity with the ionic species affects the dependence of the integral capacitance on the pore size. Up to 30% increase in the integral capacitance can be achieved even at a very low impurity bulk concentration. By comparing with an ionic liquid mixture containing modified ionic species, we find that the cooperative effect of the bounded impurities is mainly responsible for the significant enhancement of the supercapacitor performance.

Accurate Measurement of the Optical Constants for Organic and Organophosphorous Liquid Layers and Drops

DOE Office of Scientific and Technical Information (OSTI.GOV)

Myers, Tanya L.; Tonkyn, Russell G.; Danby, Tyler O.

We present accurate measurements for the determination of the optical constants for a series of organic liquids, including organophosphorous compounds. Bulk liquids are rarely encountered in the environment, but more commonly are present as droplets of liquids or thin layers on various substrates. Providing reference spectra to account for the plethora of morphological conditions that may be encountered under different scenarios is a challenge. An alternative approach is to provide the complex optical constants, n and k, which can be used to model the optical phenomena in media and at interfaces, minimizing the need for a vast number of laboratorymore » measurements. In this work, we present improved protocols for measuring the optical constants for a series of liquids that span the range from 7800 to 400 cm-1. The broad spectral range means that one needs to account for both the strong and weak spectral features that are encountered, all of which can be useful for detection, depending on the scenario. To span this dynamic range, both long and short cells are required for accurate measurements. The protocols are presented along with experimental and modeling results for thin layers of silicone oil on aluminum.« less

Interface structure between tetraglyme and graphite

NASA Astrophysics Data System (ADS)

Minato, Taketoshi; Araki, Yuki; Umeda, Kenichi; Yamanaka, Toshiro; Okazaki, Ken-ichi; Onishi, Hiroshi; Abe, Takeshi; Ogumi, Zempachi

2017-09-01

Clarification of the details of the interface structure between liquids and solids is crucial for understanding the fundamental processes of physical functions. Herein, we investigate the structure of the interface between tetraglyme and graphite and propose a model for the interface structure based on the observation of frequency-modulation atomic force microscopy in liquids. The ordering and distorted adsorption of tetraglyme on graphite were observed. It is found that tetraglyme stably adsorbs on graphite. Density functional theory calculations supported the adsorption structure. In the liquid phase, there is a layered structure of the molecular distribution with an average distance of 0.60 nm between layers.

Fred's Flow (Canada) and Murphy Well (Australia): thick komatiitic lava flows with contrasting compositions, emplacement mechanisms and water contents

NASA Astrophysics Data System (ADS)

Siégel, Coralie; Arndt, Nicholas; Barnes, Stephen; Henriot, Anne-Laure; Haenecour, Pierre; Debaille, Vinciane; Mattielli, Nadine

2014-12-01

Two Archaean komatiitic flows, Fred's Flow in Canada and the Murphy Well Flow in Australia, have similar thicknesses (120 and 160 m) but very different compositions and internal structures. Their contrasting differentiation profiles are keys to determine the cooling and crystallization mechanisms that operated during the eruption of Archaean ultramafic lavas. Fred's Flow is the type example of a thick komatiitic basalt flow. It is strongly differentiated and consists of a succession of layers with contrasting textures and compositions. The layering is readily explained by the accumulation of olivine and pyroxene in a lower cumulate layer and by evolution of the liquid composition during downward growth of spinifex-textured rocks within the upper crust. The magmas that erupted to form Fred's Flow had variable compositions, ranging from 12 to 20 wt% MgO, and phenocryst contents from 0 to 20 vol%. The flow was emplaced by two pulses. A first ~20-m-thick pulse was followed by another more voluminous but less magnesian pulse that inflated the flow to its present 120 m thickness. Following the second pulse, the flow crystallized in a closed system and differentiated into cumulates containing 30-38 wt% MgO and a residual gabbroic layer with only 6 wt% MgO. The Murphy Well Flow, in contrast, has a remarkably uniform composition throughout. It comprises a 20-m-thick upper layer of fine-grained dendritic olivine and 2-5 vol% amygdales, a 110-120 m intermediate layer of olivine porphyry and a 20-30 m basal layer of olivine orthocumulate. Throughout the flow, MgO contents vary little, from only 30 to 33 wt%, except for the slightly more magnesian basal layer (38-40 wt%). The uniform composition of the flow and dendritic olivine habits in the upper 20 m point to rapid cooling of a highly magnesian liquid with a composition like that of the bulk of the flow. Under equilibrium conditions, this liquid should have crystallized olivine with the composition Fo94.9, but the most magnesian composition measured by electron microprobe in samples from the flow is Fo92.9. To explain these features, we propose that the parental liquid contained around 32 wt% MgO and 3 wt% H2O. This liquid degassed during the eruption, creating a supercooled liquid that solidified quickly and crystallized olivine with non-equilibrium textures and compositions.

Generation of Subsurface Voids, Incubation Effect, and Formation of Nanoparticles in Short Pulse Laser Interactions with Bulk Metal Targets in Liquid: Molecular Dynamics Study

PubMed Central

2017-01-01

The ability of short pulse laser ablation in liquids to produce clean colloidal nanoparticles and unusual surface morphology has been employed in a broad range of practical applications. In this paper, we report the results of large-scale molecular dynamics simulations aimed at revealing the key processes that control the surface morphology and nanoparticle size distributions by pulsed laser ablation in liquids. The simulations of bulk Ag targets irradiated in water are performed with an advanced computational model combining a coarse-grained representation of liquid environment and an atomistic description of laser interaction with metal targets. For the irradiation conditions that correspond to the spallation regime in vacuum, the simulations predict that the water environment can prevent the complete separation of the spalled layer from the target, leading to the formation of large subsurface voids stabilized by rapid cooling and solidification. The subsequent irradiation of the laser-modified surface is found to result in a more efficient ablation and nanoparticle generation, thus suggesting the possibility of the incubation effect in multipulse laser ablation in liquids. The simulations performed at higher laser fluences that correspond to the phase explosion regime in vacuum reveal the accumulation of the ablation plume at the interface with the water environment and the formation of a hot metal layer. The water in contact with the metal layer is brought to the supercritical state and provides an environment suitable for nucleation and growth of small metal nanoparticles from metal atoms emitted from the hot metal layer. The metal layer itself has limited stability and can readily disintegrate into large (tens of nanometers) nanoparticles. The layer disintegration is facilitated by the Rayleigh–Taylor instability of the interface between the higher density metal layer decelerated by the pressure from the lighter supercritical water. The nanoparticles emerging from the layer disintegration are rapidly cooled and solidified due to the interaction with water environment, with a cooling rate of ∼2 × 1012 K/s observed in the simulations. The computational prediction of two distinct mechanisms of nanoparticle formation yielding nanoparticles with different characteristic sizes provides a plausible explanation for the experimental observations of bimodal nanoparticle size distributions in laser ablation in liquids. The ultrahigh cooling and solidification rates suggest the possibility for generation of nanoparticles featuring metastable phases and highly nonequilibrium structures. PMID:28798858

Effect of titanium oxide compact layer in dye-sensitized solar cell prepared by liquid-phase deposition

NASA Astrophysics Data System (ADS)

Huang, Jung-Jie; Chiu, Shih-Ping; Wu, Menq-Jion; Hsu, Chun-Fa

2016-11-01

In this study, titanium dioxide films were deposited on indium tin oxide glass substrates by liquid-phase deposition (LPD) for application as the compact layer in dye-sensitized solar cells (DSSCs). A deposition solution of ammonium hexafluorotitanate and boric acid was used for TiO2 deposition. Compact layer passivation can improve DSSC performance by decreasing carrier losses from recombination at the ITO/electrolyte interface and improving the electrical contact between the ITO and the TiO2 photo-electrode. The optimum thickness of the compact layer was found to be 48 nm, which resulted in a 50 % increase in the conversion efficiency compared with cells without compact layers. The conversion efficiency can be increased from 3.55 to 5.26 %. Therefore, the LPD-TiO2 compact layer inhibits the dark current and increases the short-circuit current density effectively.

Three-dimensional textures and defects of soft material layering revealed by thermal sublimation.

PubMed

Yoon, Dong Ki; Kim, Yun Ho; Kim, Dae Seok; Oh, Seong Dae; Smalyukh, Ivan I; Clark, Noel A; Jung, Hee-Tae

2013-11-26

Layering is found and exploited in a variety of soft material systems, ranging from complex macromolecular self-assemblies to block copolymer and small-molecule liquid crystals. Because the control of layer structure is required for applications and characterization, and because defects reveal key features of the symmetries of layered phases, a variety of techniques have been developed for the study of soft-layer structure and defects, including X-ray diffraction and visualization using optical transmission and fluorescence confocal polarizing microscopy, atomic force microscopy, and SEM and transmission electron microscopy, including freeze-fracture transmission electron microscopy. Here, it is shown that thermal sublimation can be usefully combined with such techniques to enable visualization of the 3D structure of soft materials. Sequential sublimation removes material in a stepwise fashion, leaving a remnant layer structure largely unchanged and viewable using SEM, as demonstrated here using a lamellar smectic liquid crystal.

An ab initio study of the structure and dynamics of bulk liquid Ag and its liquid-vapor interface

NASA Astrophysics Data System (ADS)

Gonzalez Del Rio, Beatriz; Gonzalez Tesedo, Luis Enrique; Gonzalez Fernandez, David Jose

Several static and dynamic properties of bulk liquid Ag at a thermodynamic state near its triple point have been calculated by means of ab initio molecular dynamics simulations. The calculated static structure shows a very good agreement with the available experimental data. The dynamical structure reveals collective density excitations with an associated dispersion relation which points to a small positive dispersion. Results are also reported at a slightly higher temperature in order to study the structure of the free liquid surface. The ionic density profile shows an oscillatory behaviour with two different wavelenghts, as the spacing between the outer and first inner layer is different from that between the other inner layers.

Efficient platinum-free counter electrodes for dye-sensitized solar cell applications.

PubMed

Ahmad, Shahzada; Yum, Jun-Ho; Butt, Hans-Jürgen; Nazeeruddin, Mohammad K; Grätzel, Michael

2010-09-10

Nanoporous layers of poly(3,4-propylenedioxythiophene) (PProDOT) were fabricated by electrical-field-assisted growth using hydrophobic ionic liquids as the growing medium. A series of PProDoT layers was prepared with three different ionic liquids to control the microstructure and electrochemical properties of the resulting dye-sensitized solar cells, which were highly efficient and showed a power conversion efficiency of >9% under different sunlight intensities. The current-voltage characteristics of the counter electrodes varied depending on the ionic liquids used in the synthesis of PProDOT. The most hydrophobic ionic liquids exhibited high catalytic properties, thus resulting in high power conversion efficiency and allowing the fabrication of platinum-free, stable, flexible, and cost-effective dye-sensitized solar cells.

Integration of CubeSat Systems with Europa Surface Exploration Missions

NASA Astrophysics Data System (ADS)

Erdoǧan, Enes; Inalhan, Gokhan; Kemal Üre, Nazım

2016-07-01

Recent studies show that there is a high probability that a liquid ocean exists under thick icy surface of Jupiter's Moon Europa. The findings also show that Europa has features that are similar to Earth, such as geological activities. As a result of these studies, Europa has promising environment of being habitable and currently there are many missions in both planning and execution level that target Europa. However, these missions usually involve extremely high budgets over extended periods of time. The objective of this talk is to argue that the mission costs can be reduced significantly by integrating CubeSat systems within Europa exploration missions. In particular, we introduce an integrated CubeSat-micro probe system, which can be used for measuring the size and depth of the hypothetical liquid ocean under the icy surface of Europa. The systems consist of an entry module that houses a CubeSat combined with driller measurement probes. Driller measurement probes deploy before the system hits the surface and penetrate the surface layers of Europa. Moreover, a micro laser probe could be used to examine the layers. This process enables investigation of the properties of the icy layer and the environment beneath the surface. Through examination of different scenarios and cost analysis of the components, we show that the proposed CubeSat systems has a significant potential to reduce the cost of the overall mission. Both subsystem requirements and launch prices of CubeSats are dramatically cheaper than currently used satellites. In addition, multiple CubeSats may be used to dominate wider area in space and they are expandable in face of potential failures. In this talk we discuss both the mission design and cost reduction aspects.

Quantitative interpretation of molecular dynamics simulations for X-ray photoelectron spectroscopy of aqueous solutions

NASA Astrophysics Data System (ADS)

Olivieri, Giorgia; Parry, Krista M.; Powell, Cedric J.; Tobias, Douglas J.; Brown, Matthew A.

2016-04-01

Over the past decade, energy-dependent ambient pressure X-ray photoelectron spectroscopy (XPS) has emerged as a powerful analytical probe of the ion spatial distributions at the vapor (vacuum)-aqueous electrolyte interface. These experiments are often paired with complementary molecular dynamics (MD) simulations in an attempt to provide a complete description of the liquid interface. There is, however, no systematic protocol that permits a straightforward comparison of the two sets of results. XPS is an integrated technique that averages signals from multiple layers in a solution even at the lowest photoelectron kinetic energies routinely employed, whereas MD simulations provide a microscopic layer-by-layer description of the solution composition near the interface. Here, we use the National Institute of Standards and Technology database for the Simulation of Electron Spectra for Surface Analysis (SESSA) to quantitatively interpret atom-density profiles from MD simulations for XPS signal intensities using sodium and potassium iodide solutions as examples. We show that electron inelastic mean free paths calculated from a semi-empirical formula depend strongly on solution composition, varying by up to 30% between pure water and concentrated NaI. The XPS signal thus arises from different information depths in different solutions for a fixed photoelectron kinetic energy. XPS signal intensities are calculated using SESSA as a function of photoelectron kinetic energy (probe depth) and compared with a widely employed ad hoc method. SESSA simulations illustrate the importance of accounting for elastic-scattering events at low photoelectron kinetic energies (<300 eV) where the ad hoc method systematically underestimates the preferential enhancement of anions over cations. Finally, some technical aspects of applying SESSA to liquid interfaces are discussed.

Effect of the annealing temperature and ion-beam bombardment on the properties of solution-derived HfYGaO films as liquid crystal alignment layers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Hong-Gyu; Lee, Yun-Gun; Jang, Sang Bok

2015-11-15

Hafnium yttrium gallium oxide (HfYGaO) films were applied to liquid crystal displays (LCDs) as liquid crystal (LC) alignment layers, replacing conventional polyimide (PI) layers. The HfYGaO alignment layers were prepared by fabricating solution-processed HfYGaO films, annealing them, and treating them with ion-beam (IB) irradiation. The authors studied the effects of annealing temperature and IB irradiation of the solution-derived HfYGaO films on the orientation of LC molecules. The LC molecules on the solution-derived HfYGaO films were homogeneously and uniformly aligned by IB irradiation, irrespective of the annealing temperature. Atomic force microscopy analyses revealed that the surface reformation of the HfYGaO filmsmore » induced by IB irradiation strengthened the van der Waals force between the LC molecules and the HfYGaO films, leading to uniform LC alignment. Enhanced electro-optical characteristics were observed in the twisted-nematic (TN) LCDs based on IB-irradiated HfYGaO films compared with those of TN-LCDs based on PI layers, demonstrating the high application potential of the proposed solution-derived HfYGaO films as LC alignment layers.« less

Automatic optimization high-speed high-resolution OCT retinal imaging at 1μm

NASA Astrophysics Data System (ADS)

Cua, Michelle; Liu, Xiyun; Miao, Dongkai; Lee, Sujin; Lee, Sieun; Bonora, Stefano; Zawadzki, Robert J.; Mackenzie, Paul J.; Jian, Yifan; Sarunic, Marinko V.

2015-03-01

High-resolution OCT retinal imaging is important in providing visualization of various retinal structures to aid researchers in better understanding the pathogenesis of vision-robbing diseases. However, conventional optical coherence tomography (OCT) systems have a trade-off between lateral resolution and depth-of-focus. In this report, we present the development of a focus-stacking optical coherence tomography (OCT) system with automatic optimization for high-resolution, extended-focal-range clinical retinal imaging. A variable-focus liquid lens was added to correct for de-focus in real-time. A GPU-accelerated segmentation and optimization was used to provide real-time layer-specific enface visualization as well as depth-specific focus adjustment. After optimization, multiple volumes focused at different depths were acquired, registered, and stitched together to yield a single, high-resolution focus-stacked dataset. Using this system, we show high-resolution images of the ONH, from which we extracted clinically-relevant parameters such as the nerve fiber layer thickness and lamina cribrosa microarchitecture.

Observed microphysical structure of nimbostratus in northeast cold vortex over China

NASA Astrophysics Data System (ADS)

Zhao, Zhen; Lei, Hengchi

2014-06-01

Airborne measurements were collected during a stepwise ascent within a nimbostratus cloud associated with a northeast cold vortex in Jilin Province over China on 20 June 2005 to study cloud structure and ice particle spectra. The microphysical structure of the nimbostratus was elucidated by King liquid water probe and Particle Measuring Systems (PMS) probes aboard the research aircraft. The PMS 2D images provide detailed information on crystal habits. A thick layer of supercooled cloud is observed and Hallett-Mossop ice multiplication process is used to explain very high ice particle concentrations in the temperature region between - 3 °C and - 6 °C. From near cloud top to melting layer, ice crystals shape in the form of columns, needles, aggregations and plates. In addition, significant horizontal variability was evident on the scale of few hundred meters. Ice particle spectra in this cloud were adequately described by exponential relationships. Relationship between the intercept (N0) and slope (λ) parameters of an exponential size distribution was well characterized by a power law.

Simulation of water vapor condensation on LOX droplet surface using liquid nitrogen

NASA Technical Reports Server (NTRS)

Powell, Eugene A.

1988-01-01

The formation of ice or water layers on liquid oxygen (LOX) droplets in the Space Shuttle Main Engine (SSME) environment was investigated. Formulation of such ice/water layers is indicated by phase-equilibrium considerations under conditions of high partial pressure of water vapor (steam) and low LOX droplet temperature prevailing in the SSME preburner or main chamber. An experimental investigation was begun using liquid nitrogen as a LOX simulant. A monodisperse liquid nitrogen droplet generator was developed which uses an acoustic driver to force the stream of liquid emerging from a capillary tube to break up into a stream of regularly space uniformly sized spherical droplets. The atmospheric pressure liquid nitrogen in the droplet generator reservoir was cooled below its boiling point to prevent two phase flow from occurring in the capillary tube. An existing steam chamber was modified for injection of liquid nitrogen droplets into atmospheric pressure superheated steam. The droplets were imaged using a stroboscopic video system and a laser shadowgraphy system. Several tests were conducted in which liquid nitrogen droplets were injected into the steam chamber. Under conditions of periodic droplet formation, images of 600 micron diameter liquid nitrogen droplets were obtained with the stroboscopic video systems.

Wetted foam liquid fuel ICF target experiments

DOE PAGES

Olson, R. E.; Leeper, R. J.; Yi, S. A.; ...

2016-05-26

We are developing a new NIF experimental platform that employs wetted foam liquid fuel layer ICF capsules. We will use the liquid fuel layer capsules in a NIF sub-scale experimental campaign to explore the relationship between hot spot convergence ratio (CR) and the predictability of hot spot formation. DT liquid layer ICF capsules allow for flexibility in hot spot CR via the adjustment of the initial cryogenic capsule temperature and, hence, DT vapor density. Our hypothesis is that the predictive capability of hot spot formation is robust and 1D-like for a relatively low CR hot spot (CR~15), but will becomemore » less reliable as hot spot CR is increased to CR>20. Simulations indicate that backing off on hot spot CR is an excellent way to reduce capsule instability growth and to improve robustness to low-mode x-ray flux asymmetries. In the initial experiments, we will test our hypothesis by measuring hot spot size, neutron yield, ion temperature, and burn width to infer hot spot pressure and compare to predictions for implosions with hot spot CR's in the range of 12 to 25. Larger scale experiments are also being designed, and we will advance from sub-scale to full-scale NIF experiments to determine if 1D-like behavior at low CR is retained as the scale-size is increased. The long-term objective is to develop a liquid fuel layer ICF capsule platform with robust thermonuclear burn, modest CR, and significant α-heating with burn propagation.« less

Understanding Kelvin-Helmholtz instability in paraffin-based hybrid rocket fuels

NASA Astrophysics Data System (ADS)

Petrarolo, Anna; Kobald, Mario; Schlechtriem, Stefan

2018-04-01

Liquefying fuels show higher regression rates than the classical polymeric ones. They are able to form, along their burning surface, a low viscosity and surface tension liquid layer, which can become unstable (Kelvin-Helmholtz instability) due to the high velocity gas flow in the fuel port. This causes entrainment of liquid droplets from the fuel surface into the oxidizer gas flow. To better understand the droplets entrainment mechanism, optical investigations on the combustion behaviour of paraffin-based hybrid rocket fuels in combination with gaseous oxygen have been conducted in the framework of this research. Combustion tests were performed in a 2D single-slab burner at atmospheric conditions. High speed videos were recorded and analysed with two decomposition techniques. Proper orthogonal decomposition (POD) and independent component analysis (ICA) were applied to the scalar field of the flame luminosity. The most excited frequencies and wavelengths of the wave-like structures characterizing the liquid melt layer were computed. The fuel slab viscosity and the oxidizer mass flow were varied to study their influence on the liquid layer instability process. The combustion is dominated by periodic, wave-like structures for all the analysed fuels. Frequencies and wavelengths characterizing the liquid melt layer depend on the fuel viscosity and oxidizer mass flow. Moreover, for very low mass flows, no wavelength peaks are detected for the higher viscosity fuels. This is important to better understand and predict the onset and development of the entrainment process, which is connected to the amplification of the longitudinal waves.

Multiple layer identification label using stacked identification symbols

NASA Technical Reports Server (NTRS)

Schramm, Harry F. (Inventor)

2005-01-01

An automatic identification system and method are provided which employ a machine readable multiple layer label. The label has a plurality of machine readable marking layers stacked one upon another. Each of the marking layers encodes an identification symbol detectable using one or more sensing technologies. The various marking layers may comprise the same marking material or each marking layer may comprise a different medium having characteristics detectable by a different sensing technology. These sensing technologies include x-ray, radar, capacitance, thermal, magnetic and ultrasonic. A complete symbol may be encoded within each marking layer or a symbol may be segmented into fragments which are then divided within a single marking layer or encoded across multiple marking layers.

Polysulfide intercalated layered double hydroxides for metal capture applications

DOEpatents

Kanatzidis, Mercouri G.; Ma, Shulan

2017-04-04

Polysulfide intercalated layered double hydroxides and methods for their use in vapor and liquid-phase metal capture applications are provided. The layered double hydroxides comprise a plurality of positively charged host layers of mixed metal hydroxides separated by interlayer spaces. Polysulfide anions are intercalated in the interlayer spaces.

Formation of multiple levels of porous silicon for buried insulators and conductors in silicon device technologies

DOEpatents

Blewer, Robert S.; Gullinger, Terry R.; Kelly, Michael J.; Tsao, Sylvia S.

1991-01-01

A method of forming a multiple level porous silicon substrate for semiconductor integrated circuits including anodizing non-porous silicon layers of a multi-layer silicon substrate to form multiple levels of porous silicon. At least one porous silicon layer is then oxidized to form an insulating layer and at least one other layer of porous silicon beneath the insulating layer is metallized to form a buried conductive layer. Preferably the insulating layer and conductive layer are separated by an anodization barrier formed of non-porous silicon. By etching through the anodization barrier and subsequently forming a metallized conductive layer, a fully or partially insulated buried conductor may be fabricated under single crystal silicon.

Microfluidic electrochemical device and process for chemical imaging and electrochemical analysis at the electrode-liquid interface in-situ

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yu, Xiao-Ying; Liu, Bingwen; Yang, Li

2016-03-01

A microfluidic electrochemical device and process are detailed that provide chemical imaging and electrochemical analysis under vacuum at the surface of the electrode-sample or electrode-liquid interface in-situ. The electrochemical device allows investigation of various surface layers including diffuse layers at selected depths populated with, e.g., adsorbed molecules in which chemical transformation in electrolyte solutions occurs.

On the shedding of impaled droplets: The role of transient intervening layers

NASA Astrophysics Data System (ADS)

Stamatopoulos, Christos; Schutzius, Thomas M.; Köppl, Christian J.; Hayek, Nicolas El; Maitra, Tanmoy; Hemrle, Jaroslav; Poulikakos, Dimos

2016-01-01

Maintaining the non-wetting property of textured hydrophobic surfaces is directly related to the preservation of an intervening fluid layer (gaseous or immiscible liquid) between the droplet and substrate; once displaced, it cannot be recovered spontaneously as the fully penetrated Wenzel wetting state is energetically favorable. Here, we identify pathways for the “lifting” of droplets from the surface texture, enabling a complete Wenzel-to-Cassie-Baxter wetting state transition. This is accomplished by the hemiwicking of a transient (limited lifetime due to evaporation) low surface tension (LST) liquid, which is capable of self-assembling as an intervening underlayer, lifting the droplet from its impaled state and facilitating a skating-like behavior. In the skating phase, a critical substrate tilting angle is identified, up to which underlayer and droplet remain coupled exhibiting a pseudo-Cassie-Baxter state. For greater titling angles, the droplet, driven by inertia, detaches itself from the liquid intervening layer and transitions to a traditional Cassie-Baxter wetting state, thereby accelerating and leaving the underlayer behind. A model is also presented that elucidates the mechanism of mobility recovery. Ultimately, this work provides a better understanding of multiphase mass transfer of immiscible LST liquid-water mixtures with respect to establishing facile methods towards retaining intervening layers.

On the shedding of impaled droplets: The role of transient intervening layers

PubMed Central

Stamatopoulos, Christos; Schutzius, Thomas M.; Köppl, Christian J.; Hayek, Nicolas El; Maitra, Tanmoy; Hemrle, Jaroslav; Poulikakos, Dimos

2016-01-01

Maintaining the non-wetting property of textured hydrophobic surfaces is directly related to the preservation of an intervening fluid layer (gaseous or immiscible liquid) between the droplet and substrate; once displaced, it cannot be recovered spontaneously as the fully penetrated Wenzel wetting state is energetically favorable. Here, we identify pathways for the “lifting” of droplets from the surface texture, enabling a complete Wenzel-to-Cassie-Baxter wetting state transition. This is accomplished by the hemiwicking of a transient (limited lifetime due to evaporation) low surface tension (LST) liquid, which is capable of self-assembling as an intervening underlayer, lifting the droplet from its impaled state and facilitating a skating-like behavior. In the skating phase, a critical substrate tilting angle is identified, up to which underlayer and droplet remain coupled exhibiting a pseudo-Cassie-Baxter state. For greater titling angles, the droplet, driven by inertia, detaches itself from the liquid intervening layer and transitions to a traditional Cassie-Baxter wetting state, thereby accelerating and leaving the underlayer behind. A model is also presented that elucidates the mechanism of mobility recovery. Ultimately, this work provides a better understanding of multiphase mass transfer of immiscible LST liquid-water mixtures with respect to establishing facile methods towards retaining intervening layers. PMID:26743806

Is the boundary layer of an ionic liquid equally lubricating at higher temperature?

PubMed

Hjalmarsson, Nicklas; Atkin, Rob; Rutland, Mark W

2016-04-07

Atomic force microscopy has been used to study the effect of temperature on normal forces and friction for the room temperature ionic liquid (IL) ethylammonium nitrate (EAN), confined between mica and a silica colloid probe at 25 °C, 50 °C, and 80 °C. Force curves revealed a strong fluid dynamic influence at room temperature, which was greatly reduced at elevated temperatures due to the reduced liquid viscosity. A fluid dynamic analysis reveals that bulk viscosity is manifested at large separation but that EAN displays a nonzero slip, indicating a region of different viscosity near the surface. At high temperatures, the reduction in fluid dynamic force reveals step-like force curves, similar to those found at room temperature using much lower scan rates. The ionic liquid boundary layer remains adsorbed to the solid surface even at high temperature, which provides a mechanism for lubrication when fluid dynamic lubrication is strongly reduced. The friction data reveals a decrease in absolute friction force with increasing temperature, which is associated with increased thermal motion and reduced viscosity of the near surface layers but, consistent with the normal force data, boundary layer lubrication was unaffected. The implications for ILs as lubricants are discussed in terms of the behaviour of this well characterised system.

Controllable liquid colour-changing lenses with microfluidic channels for vision protection, camouflage and optical filtering based on soft lithography fabrication.

PubMed

Zhang, Min; Li, Songjing

2016-01-01

In this work, liquid colour-changing lenses for vision protection, camouflage and optical filtering are developed by circulating colour liquids through microfluidic channels on the lenses manually. Soft lithography technology is applied to fabricate the silicone liquid colour-changing layers with microfluidic channels on the lenses instead of mechanical machining. To increase the hardness and abrasion resistance of the silicone colour-changing layers on the lenses, proper fabrication parameters such as 6:1 (mass ration) mixing proportion and 100 °C curing temperature for 2 h are approved for better soft lithography process of the lenses. Meanwhile, a new surface treatment for the irreversible bonding of silicone colour-changing layer with optical resin (CR39) substrate lens by using 5 % (volume ratio) 3-Aminopropyltriethoxysilane solution is proposed. Vision protection, camouflage and optical filtering functions of the lenses are investigated with different designs of the channels and multi-layer structures. Each application can not only well achieve their functional demands, but also shows the advantages of functional flexibility, rapid prototyping and good controllability compared with traditional ways. Besides optometry, some other designs and applications of the lenses are proposed for potential utility in the future.

Plasma carburizing with surface micro-melting

NASA Astrophysics Data System (ADS)

Balanovsky, A. E.; Grechneva, M. V.; Van Huy, Vu; Ponomarev, B. B.

2018-03-01

This paper presents carburizing the surface of 20 low carbon steel using electric arc and graphite prior. A carbon black solution was prepared with graphite powder and sodium silicate in water. A detailed analysis of the phase structure and the distribution profile of the sample hardness after plasma treatment were given. The hardened layer consists of three different zones: 1 – the cemented layer (thin white zone) on the surface, 2 – heat-affected zone (darkly etching structure), 3 – the base metal. The experimental result shows that the various microstructures and micro-hardness profiles were produced depending on the type of graphite coating (percentage of liquid glass) and processing parameters. The experiment proved that the optimum content of liquid glass in graphite coating is 50–87.5%. If the amount of liquid glass is less than 50%, adhesion to metal is insufficient. If liquid glass content is more than 87.5%, carburization of a metal surface does not occur. A mixture of the eutectic lamellar structure, martensite and austenite was obtained by using graphite prior with 67% sodium silicate and the levels of the hardness layer increased to around 1000 HV. The thickness of the cemented layer formed on the surface was around 200 μm. It is hoped that this plasma surface carburizing treatment could improve the tribological resistance properties.

TANK 32 EVAPORATOR FEED PUMP TRANSFER ANALYSIS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tamburello, D; Richard Dimenna, R; Si Lee, S

2009-01-27

The transfer of liquid salt solution from Tank 32 to an evaporator is to be accomplished by activating the evaporator feed pump, with the supernate surface at a minimum height of approximately 74.4 inches above the sludge layer, while simultaneously turning on the downcomer with a flow rate of 110 gpm. Previously, activation of the evaporator feed pump was an isolated event without any other components running at the same time. An analysis of the dissolved solution transfer has been performed using computational fluid dynamics (CFD) methods to determine the amount of entrained sludge solids pumped out of the tankmore » toward the evaporator with the downcomer turned on. The analysis results shows that, for the minimum tank liquid level of 105 inches above the tank bottom (which corresponds to a liquid depth of 74.4 inches above the sludge layer), the evaporator feed pump will contain less than 0.1 wt% sludge solids in the discharge stream, which is an order of magnitude less than the 1.0 wt% undissolved solids (UDS) loading criteria to feed the evaporator. Lower liquid levels with respect to the sludge layer will result in higher amounts of sludge entrainment due to the increased plunging jet velocity from the downcomer disturbing the sludge layer.« less

Accelerating dewetting on deformable substrates by adding a liquid underlayer.

PubMed

Xu, Lin; Reiter, Günter; Shi, Tongfei; An, Lijia

2010-05-18

We investigated the dependence of the dewetting velocity of a thin, low-viscosity polystyrene (PS) top film on a poly(methyl methacrylate) (PMMA) double layer consisting of a low-viscosity underlayer of thickness h(L) coated with a high-viscosity middle layer of thickness h(M). The addition of the liquid underlayer generated complex nonmonotonic behavior of the dewetting velocity as a function of increasing h(M). In particular, we observed an acceleration of dewetting for an intermediate range of h(M). This phenomenon has been interpreted by a combination deformation of the middle elastic layer and a concurrent change in the contact angle. On one hand, deformation led to the formation of a trench that dissipated energy during its movement through the liquid underlayer and thus caused a slowing down of dewetting. However, with an increase in the thickness of the elastic middle layer, the size of the trench decreased and its influence on the dewetting velocity also decreased. On the other hand, the deformation of the elastic layer also led to an increase in the contact angle. This increase in the driving capillary forces caused an increase in the dewetting velocity.

Effect of Group-III precursors on unintentional gallium incorporation during epitaxial growth of InAlN layers by metalorganic chemical vapor deposition

NASA Astrophysics Data System (ADS)

Kim, Jeomoh; Ji, Mi-Hee; Detchprohm, Theeradetch; Dupuis, Russell D.; Fischer, Alec M.; Ponce, Fernando A.; Ryou, Jae-Hyun

2015-09-01

Unintentional incorporation of gallium (Ga) in InAlN layers grown with different molar flow rates of Group-III precursors by metalorganic chemical vapor deposition has been experimentally investigated. The Ga mole fraction in the InAl(Ga)N layer was increased significantly with the trimethylindium (TMIn) flow rate, while the trimethylaluminum flow rate controls the Al mole fraction. The evaporation of metallic Ga from the liquid phase eutectic system between the pyrolized In from injected TMIn and pre-deposited metallic Ga was responsible for the Ga auto-incorporation into the InAl(Ga)N layer. The theoretical calculation on the equilibrium vapor pressure of liquid phase Ga and the effective partial pressure of Group-III precursors based on growth parameters used in this study confirms the influence of Group-III precursors on Ga auto-incorporation. More Ga atoms can be evaporated from the liquid phase Ga on the surrounding surfaces in the growth chamber and then significant Ga auto-incorporation can occur due to the high equilibrium vapor pressure of Ga comparable to effective partial pressure of input Group-III precursors during the growth of InAl(Ga)N layer.

Multilayer electronic component systems and methods of manufacture

NASA Technical Reports Server (NTRS)

Thompson, Dane (Inventor); Wang, Guoan (Inventor); Kingsley, Nickolas D. (Inventor); Papapolymerou, Ioannis (Inventor); Tentzeris, Emmanouil M. (Inventor); Bairavasubramanian, Ramanan (Inventor); DeJean, Gerald (Inventor); Li, RongLin (Inventor)

2010-01-01

Multilayer electronic component systems and methods of manufacture are provided. In this regard, an exemplary system comprises a first layer of liquid crystal polymer (LCP), first electronic components supported by the first layer, and a second layer of LCP. The first layer is attached to the second layer by thermal bonds. Additionally, at least a portion of the first electronic components are located between the first layer and the second layer.

Multiple density layered insulator

DOEpatents

Alger, Terry W.

1994-01-01

A multiple density layered insulator for use with a laser is disclosed wh provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation.

Reflection of acoustic wave from the elastic seabed with an overlying gassy poroelastic layer

NASA Astrophysics Data System (ADS)

Chen, Weiyun; Wang, Zhihua; Zhao, Kai; Chen, Guoxing; Li, Xiaojun

2015-10-01

Based on the multiphase poroelasticity theory, the reflection characteristics of an obliquely incident acoustic wave upon a plane interface between overlying water and a gassy marine sediment layer with underlying elastic solid seabed are investigated. The sandwiched gassy layer is modelled as a porous material with finite thickness, which is saturated by two compressible and viscous fluids (liquid and gas). The closed-form expression for the amplitude ratio of the reflected wave, called reflection coefficient, is derived theoretically according to the boundary conditions at the upper and lower interfaces in our proposed model. Using numerical calculation, the influences of layer thickness, incident angle, wave frequency and liquid saturation of sandwiched porous layer on the reflection coefficient are analysed, respectively. It is revealed that the reflection coefficient is closely associated with incident angle and sandwiched layer thickness. Moreover, in different frequency ranges, the dependence of the wave reflection characteristics on moisture (or gas) variations in the intermediate marine sediment layer is distinguishing.

Generation and characterization of surface layers on acoustically levitated drops.

PubMed

Tuckermann, Rudolf; Bauerecker, Sigurd; Cammenga, Heiko K

2007-06-15

Surface layers of natural and technical amphiphiles, e.g., octadecanol, stearic acid and related compounds as well as perfluorinated fatty alcohols (PFA), have been investigated on the surface of acoustically levitated drops. In contrast to Langmuir troughs, traditionally used in the research of surface layers at the air-water interface, acoustic levitation offers the advantages of a minimized and contact-less technique. Although the film pressure cannot be directly adjusted on acoustically levitated drops, it runs through a wide pressure range due to the shrinking surface of an evaporating drop. During this process, different states of the generated surface layer have been identified, in particular the phase transition from the gaseous or liquid-expanded to the liquid-condensed state of surface layers of octadecanol and other related amphiphiles. Characteristic parameters, such as the relative permeation resistance and the area per molecule in a condensed surface layer, have been quantified and were found comparable to results obtained from surface layers generated on Langmuir troughs.

First liquid-layer implosion experiments at the NIF

NASA Astrophysics Data System (ADS)

Zylstra, Alex

2017-10-01

Replacing the standard ice layer in an ignition design with a liquid layer allows fielding the target with a higher central vapor pressure, leading to reduced implosion convergence ratio (CR). At lower CR, the implosions are expected to be more robust to instabilities and asymmetries than standard ice-layer designs, and are also unique in that the hot spot can be primarily formed from material originating in the central fuel vapor. The first liquid-layer implosions on the National Ignition Facility (NIF) have been performed by wicking the liquid fuel into a supporting foam that lines the inside surface of the capsule. A series of shots has been conducted between CR of 12 and 20 using a HDC ablator driven by a 3-shock pulse in a near-vacuum Au hohlraum. At the lowest CR the implosion performance is well predicted by 2-D radiation-hydrodynamics calculations. However, as the CR is increased the nominal simulations do not capture the experimentally observed trends. Data-based models suggest that the hot spot formation is unexpectedly suppressed at higher convergence. The data could be explained by reduced hydrodynamic coupling efficiency, or an anomalously enhanced thermal conductivity in the mixed DT/foam material. We show that the latter hypothesis can explain observed trends in several experimental metrics, including the yield, ion temperature, and burn duration. This work was performed under the auspices of the U.S. DoE by LANL under contract DE-AC52-06NA52396.

Convection Models for Ice-Water System: Dynamical Investigation of Phase Transition

NASA Astrophysics Data System (ADS)

Allu Peddinti, D.; McNamara, A. K.

2012-12-01

Ever since planetary missions of Voyager and Galileo revealed a dynamically altered surface of the icy moon Europa, a possible subsurface ocean under an icy shell has been speculated and surface features have been interpreted from an interior dynamics perspective. The physics of convection in a two phase water-ice system is governed by a wide set of physical parameters that include melting viscosity of ice, the variation of viscosity due to pressure and temperature, temperature contrast across and tidal heating within the system, and the evolving thickness of each layer. Due to the extreme viscosity contrast between liquid water and solid ice, it is not feasible to model the entire system to study convection. However, using a low-viscosity proxy (higher viscosity than the liquid water but much lower than solid ice) for the liquid phase provides a convenient approximation of the system, and allows for a relatively realistic representation of convection within the ice layer while also providing a self-consistent ice layer thickness that is a function of the thermal state of the system. In order to apply this method appropriately, we carefully examine the upper bound of viscosity required for the low-viscosity proxy to adequately represent the liquid phase. We identify upper bounds on the viscosity of the proxy liquid such that convective dynamics of the ice are not affected by further reductions of viscosity. Furthermore, we investigate how the temperature contrast across the system and viscosity contrast between liquid and ice control ice layer thickness. We also investigate ice shell thickening as a function of cooling, particularly how viscosity affects the conduction-to-convection transition within the ice shell. Finally, we present initial results that investigate the effects that latent heat of fusion (due to the ice-water phase transition) has on ice convection.

Polydimethylsiloxane as dielectric and hydrophobic material in electro-wetting liquid lens

NASA Astrophysics Data System (ADS)

Wang, Liang; Duan, Junping; Zhang, Binzhen; Wang, Wanjun

2016-10-01

An electro-wetting-based variable-focus liquid lens with a spin coated polydimethylsiloxane (PDMS) layer is presented. The PDMS layer acts as both insulation and hydrophobic material of the liquid lens. By changing the applied voltage between the two electrodes, the radius of the water-oil contact curved surface is adjusted to realize the zoom function. In preparation process, at first, the liquid lens is divided into two parts, the PDMS substrate and the cavity, and then two parts of liquid lens are bonding together after surface treatment. After liquid injection and sealing cavity, the whole process was accomplished. The zooming performance of lens is tested, and COMSOL is used to analyze the shape of the water-oil contact curved surface at different voltages, the results shows that with the applied voltage changing from 0V to 120V, the height of meniscus vertex reduced from 2.41mm to 1.67mm, and the focal length changes from -14.3mm to infinity first, and then to 27.1mm.

Photolithography-Based Patterning of Liquid Metal Interconnects for Monolithically Integrated Stretchable Circuits.

PubMed

Park, Chan Woo; Moon, Yu Gyeong; Seong, Hyejeong; Jung, Soon Won; Oh, Ji-Young; Na, Bock Soon; Park, Nae-Man; Lee, Sang Seok; Im, Sung Gap; Koo, Jae Bon

2016-06-22

We demonstrate a new patterning technique for gallium-based liquid metals on flat substrates, which can provide both high pattern resolution (∼20 μm) and alignment precision as required for highly integrated circuits. In a very similar manner as in the patterning of solid metal films by photolithography and lift-off processes, the liquid metal layer painted over the whole substrate area can be selectively removed by dissolving the underlying photoresist layer, leaving behind robust liquid patterns as defined by the photolithography. This quick and simple method makes it possible to integrate fine-scale interconnects with preformed devices precisely, which is indispensable for realizing monolithically integrated stretchable circuits. As a way for constructing stretchable integrated circuits, we propose a hybrid configuration composed of rigid device regions and liquid interconnects, which is constructed on a rigid substrate first but highly stretchable after being transferred onto an elastomeric substrate. This new method can be useful in various applications requiring both high-resolution and precisely aligned patterning of gallium-based liquid metals.

Phase-Field Simulation of Concentration and Temperature Distribution During Dendritic Growth in a Forced Liquid Metal Flow

NASA Astrophysics Data System (ADS)

Du, Lifei; Zhang, Rong

2014-12-01

A phase-field model with convection is employed to investigate the effect of liquid flow on the dendritic structure formation of a Ni-Cu alloy during rapid solidification. Temperature and solute diffusion are significantly changed with induced liquid metal flow, and distribution changes of concentration and temperature are also analyzed and discussed. The solute segregation is affected due to the concentration diffusion layer thickness change caused by the liquid flow. The flow reduces the solute segregation in the upstream and leads to a fast dendrite growing, while solidifying in the downstream gets constrained with the large solute diffusion layer. Increasing flow velocity increases the asymmetry of dendrite morphology with much more suppressed growth in the downstream. The temperature distribution is also asymmetrical due to the non-uniform latent heat released during solidification coupling with heat diffusion changed by the liquid flow. Therefore, the forced liquid flow significantly affects the dendrite morphology, concentration, and temperature distributions in the solidifying microstructure.

Boundary-layer exchange by bubble: A novel method for generating transient nanofluidic layers

NASA Astrophysics Data System (ADS)

Jennissen, Herbert P.

2005-10-01

Unstirred layers (i.e., Nernst boundary layers) occur on every dynamic solid-liquid interface, constituting a diffusion barrier, since the velocity of a moving liquid approaches zero at the surface (no slip). If a macromolecule-surface reaction rate is higher than the diffusion rate, the Nernst layer is solute depleted and the reaction rate becomes mass-transport limited. The thickness of a Nernst boundary layer (δN) generally lies between 5 and 50μm. In an evanescent wave rheometer, measuring fibrinogen adsorption to fused silica, we made the fundamental observation that an air bubble preceding the sample through the flow cell abolishes the mass-transport limitation of the Nernst diffusion layer. Instead exponential kinetics are found. Experimental and simulation studies strongly indicate that these results are due to the elimination of the Nernst diffusion layer and its replacement by a dynamic nanofluidic layer (δν) maximally 200-300nm thick. It is suggested that the air bubble leads to a transient boundary-layer separation into a novel nanoboundary layer on the surface and the bulk fluid velocity profile separated by a vortex sheet with an estimated lifetime of 30-60s. A bubble-induced boundary-layer exchange from the Nernst to the nanoboundary layer and back is obtained, giving sufficient time for the measurement of unbiased exponential surface kinetics. Noteworthy is that the nanolayer can exist at all and displays properties such as (i) a long persistence and resistance to dissipation by the bulk liquid (boundary-layer-exchange-hysteresis) and (ii) a lack of solute depletion in spite of boundary-layer separation. The boundary-layer-exchange by bubble (BLEB) method therefore appears ideal for enhancing the rates of all types of diffusion-limited macromolecular reactions on surfaces with contact angles between 0° and 90° and only appears limited by slippage due to nanobubbles or an air gap beneath the nanofluidic layer on very hydrophobic surfaces. The possibility of producing nanoboundary layers without any nanostructuring or nanomachining should also be useful for fundamental physical studies in nanofluidics.

Phase transition detection by surface photo charge effect in liquid crystals

NASA Astrophysics Data System (ADS)

Ivanov, O.; Petrov, M.; Naradikian, H.; Perez-Diaz, J. L.

2018-05-01

The surface photo charge effect (SPCE) was applied for the first time at structure and phase transitions study of hydrogen bonded in dimer liquid crystals (HBDLCs). Due to the high sensitivity of this method, besides first-order phase transitions, characteristic for the p,n-octyloxibenzoic acids (8OBA), an order transition was definitely detected within the nematic range. We state that the SPCE, arising at the solid-HBDLCs interface due to the double electrical layer, is invariably concomitant with solid surface-liquid interfaces, and indicates that the changes of the characteristics of this layer, under incident optical irradiation, induce surface charge rearrangement and alternating potential difference. A mechanism of induction of the SPCE at the interface of solid surface-anisotropic liquids is proposed. We also indicate that this mechanism can be adapted for solid surface-isotropic liquid interface, including colloids (milk) and fog (aerosols)-condensed medium.

Deconstructing Temperature Gradients across Fluid Interfaces: The Structural Origin of the Thermal Resistance of Liquid-Vapor Interfaces

NASA Astrophysics Data System (ADS)

Muscatello, Jordan; Chacón, Enrique; Tarazona, Pedro; Bresme, Fernando

2017-07-01

The interfacial thermal resistance determines condensation-evaporation processes and thermal transport across material-fluid interfaces. Despite its importance in transport processes, the interfacial structure responsible for the thermal resistance is still unknown. By combining nonequilibrium molecular dynamics simulations and interfacial analyses that remove the interfacial thermal fluctuations we show that the thermal resistance of liquid-vapor interfaces is connected to a low density fluid layer that is adsorbed at the liquid surface. This thermal resistance layer (TRL) defines the boundary where the thermal transport mechanism changes from that of gases (ballistic) to that characteristic of dense liquids, dominated by frequent particle collisions involving very short mean free paths. We show that the thermal conductance is proportional to the number of atoms adsorbed in the TRL, and hence we explain the structural origin of the thermal resistance in liquid-vapor interfaces.

A new real-time non-coherent to coherent light image converter - The hybrid field effect liquid crystal light valve

NASA Technical Reports Server (NTRS)

Grinberg, J.; Jacobson, A.; Bleha, W.; Miller, L.; Fraas, L.; Boswell, D.; Myer, G.

1975-01-01

A new, high-performance device has been developed for application to real-time coherent optical data processing. The new device embodies a CdS photoconductor, a CdTe light-absorbing layer, a dielectric mirror, and a liquid crystal layer sandwiched between indium-tin-oxide transparent electrodes deposited on optical quality glass flats. The noncoherent image is directed onto the photoconductor; this reduces the impedance of the photoconductor, thereby switching the ac voltage that is impressed across the electrodes onto the liquid crystal to activate the device. The liquid crystal is operated in a hybrid field effect mode. It utilizes the twisted nematic effect to create a dark off-state and the optical birefringence effect to create the bright on-state. The liquid crystal modulates the polarization of the coherent read-out light so an analyzer must be used to create an intensity modulated output beam.

Electrostatic Debye layer formed at a plasma-liquid interface

NASA Astrophysics Data System (ADS)

Rumbach, Paul; Clarke, Jean Pierre; Go, David B.

2017-05-01

We construct an analytic model for the electrostatic Debye layer formed at a plasma-liquid interface by combining the Gouy-Chapman theory for the liquid with a simple parabolic band model for the plasma sheath. The model predicts a nonlinear scaling between the plasma current density and the solution ionic strength, and we confirmed this behavior with measurements using a liquid-anode plasma. Plots of the measured current density as a function of ionic strength collapse the data and curve fits yield a plasma electron density of ˜1019m-3 and an electric field of ˜104V /m on the liquid side of the interface. Because our theory is based firmly on fundamental physics, we believe it can be widely applied to many emerging technologies involving the interaction of low-temperature, nonequilibrium plasma with aqueous media, including plasma medicine and various plasma chemical synthesis techniques.

Liquid Water Saturation and Oxygen Transport Resistance in Polymer Electrolyte Membrane Fuel Cell Gas Diffusion Layers

NASA Astrophysics Data System (ADS)

Muirhead, Daniel

In this thesis, the relative humidity (RH) of the cathode reactant gas was investigated as a factor which influences gas diffusion layer (GDL) liquid water accumulation and mass transport-related efficiency losses over a range of operating current densities in a polymer electrolyte membrane (PEM) fuel cell. Limiting current measurements were used to characterize fuel cell oxygen transport resistance while simultaneous measurements of liquid water accumulation were conducted using synchrotron X-ray radiography. GDL porosity distributions were characterized with micro-computed tomography (microCT). The work presented here can be used by researchers to develop improved numerical models to predict GDL liquid water accumulation and to inform the design of next-generation GDL materials to mitigate mass transport-related efficiency losses. This work also contributes an extensive set of concurrent performance and liquid water visualization data to the PEM fuel cell field that can be used for validating multiphase transport models.

Micropellets coated with Kollicoat® Smartseal 30D for taste masking in liquid oral dosage forms.

PubMed

Dashevskiy, Andriy; Mohylyuk, Valentyn; Ahmed, Abid Riaz; Kolter, Karl; Guth, Felicitas; Bodmeier, Roland

2017-09-01

The objective of this study was to develop delivery systems for taste masking based on multiparticulates coated with Kollicoat ® Smartseal 30D formulated as liquid oral suspensions. Coating of particles containing bitter drugs with Kollicoat ® Smartseal reduced drug leaching into aqueous medium, especially when increasing pH, therefore can be used for the formulation of liquid dosage forms. Application of an intermediate layer of ion exchange resins between drug layer and coating can further decrease drug leaching into aqueous vehicle that is beneficial in terms of taste masking. Using optimized compositions of liquid vehicles such as addition of sugar alcohols and ion exchange resin, reconstitutable or ready-to-use liquid dosage forms with micropellets can be developed with bitter taste protection after redispersion lasting longer than 3 weeks, which exceeds the usual period of application.

Evaluation of ACCESS Model Cloud Properties Over the SouthernOcean Area Using Multiple-satellite ProductsSan Luo1,2 Zhian Sun2, Xiaogu Zheng1, Lawrie Rikus2 and Charmaine Franklin31 College of Global Change and Earth System Science, Beijing Normal University, China 2 Collaboration for Australian Weather and Climate Research3 CSIRO

NASA Astrophysics Data System (ADS)

Luo, S.

2016-12-01

Radiation field and cloud properties over the Southern Ocean area generated by the Australian Community Climate and Earth System Simulator (ACCESS) are evaluated using multiple-satellite products from the Fast Longwave And Shortwave radiative Fluxes (FLASHFlux) project and NASA/GEWEX surface radiation budget (SRB) data. The cloud properties are also evaluated using the observational simulator package COSP, a synthetic brightness temperature model (SBTM) and cloud liquid-water path data (UWisc) from the University of Wisconsin satellite retrievals. All of these evaluations are focused on the Southern Ocean area in an effort to understand the reasons behind the short-wave radiation biases at the surface. It is found that the model overestimates the high-level cloud fraction and frequency of occurrence of small ice-water content and underestimates the middle and low-level cloud fraction and water content. In order to improve the modelled radiation fields over the Southern Ocean area, two main modifications have been made to the physical schemes in the ACCESS model. Firstly the autoconversion rate at which the cloud water is converted into rain and the accretion rate in the warm rain scheme have been modified, which increases the cloud liquid-water content in warm cloud layers. Secondly, the scheme which determines the fraction of supercooled liquid water in mixed-phase clouds in the parametrization of cloud optical properties has been changed to use one derived from CALIPSO data which provides larger liquid cloud fractions and thus higher optical depths than the default scheme. Sensitivity tests of these two schemes in ACCESS climate runs have shown that applying either can lead to a reduction of the solar radiation reaching the surface and reduce the short-wave radiation biases.

Multiple density layered insulator

DOEpatents

Alger, T.W.

1994-09-06

A multiple density layered insulator for use with a laser is disclosed which provides at least two different insulation materials for a laser discharge tube, where the two insulation materials have different thermoconductivities. The multiple layer insulation materials provide for improved thermoconductivity capability for improved laser operation. 4 figs.

Wet powder seal for gas containment

DOEpatents

Stang, Louis G.

1982-01-01

A gas seal is formed by a compact layer of an insoluble powder and liquid filling the fine interstices of that layer. The smaller the particle size of the selected powder, such as sand or talc, the finer will be the interstices or capillary spaces in the layer and the greater will be the resulting sealing capacity, i.e., the gas pressure differential which the wet powder layer can withstand. Such wet powder seal is useful in constructing underground gas reservoirs or storage cavities for nuclear wastes as well as stopping leaks in gas mains buried under ground or situated under water. The sealing capacity of the wet powder seal can be augmented by the hydrostatic head of a liquid body established over the seal.

Wet powder seal for gas containment

DOEpatents

Stang, L.G.

1979-08-29

A gas seal is formed by a compact layer of an insoluble powder and liquid filling the fine interstices of that layer. The smaller the particle size of the selected powder, such as sand or talc, the finer will be the interstices or capillary spaces in the layer and the greater will be the resulting sealing capacity, i.e., the gas pressure differential which the wet powder layer can withstand. Such wet powder seal is useful in constructing underground gas reservoirs or storage cavities for nuclear wastes as well as stopping leaks in gas mains buried under ground or situated under water. The sealing capacity of the wet powder seal can be augmented by the hydrostatic head of a liquid body established over the seal.

Interplay between dewetting and layer inversion in poly(4-vinylpyridine)/polystyrene bilayers.

PubMed

Thickett, Stuart C; Harris, Andrew; Neto, Chiara

2010-10-19

We investigated the morphology and dynamics of the dewetting of metastable poly(4-vinylpyridine) (P4VP) thin films situated on top of polystyrene (PS) thin films as a function of the molecular weight and thickness of both films. We focused on the competition between the dewetting process, occurring as a result of unfavorable intermolecular interactions at the P4VP/PS interface, and layer inversion due to the lower surface energy of PS. By means of optical and atomic force microscopy (AFM), we observed how both the dynamics of the instability and the morphology of the emerging patterns depend on the ratio of the molecular weights of the polymer films. When the bottom PS layer was less viscous than the top P4VP layer (liquid-liquid dewetting), nucleated holes in the P4VP film typically stopped growing at long annealing times because of a combination of viscous dissipation in the bottom layer and partial layer inversion. Full layer inversion was achieved when the viscosity of the top P4VP layer was significantly greater (>10⁴) than the viscosity of the PS layer underneath, which is attributed to strongly different mobilities of the two layers. The density of holes produced by nucleation dewetting was observed for the first time to depend on the thickness of the top film as well as the polymer molecular weight. The final (completely dewetted) morphology of isolated droplets could be achieved only if the time frame of layer inversion was significantly slower than that of dewetting, which was characteristic of high-viscosity PS underlayers that allowed dewetting to fall into a liquid-solid regime. Assuming a simple reptation model for layer inversion occurring at the dewetting front, the observed surface morphologies could be predicted on the basis of the relative rates of dewetting and layer inversion.

A model experiment of liquefaction and fluid transport: quantifying the effect of permeability discontinuity

NASA Astrophysics Data System (ADS)

Yasuda, N.; Sumita, I.

2013-12-01

Model experiments of liquefaction of a water-saturated sand (quick sand) is commonly conducted in class and in public. Various phenomena caused by liquefaction are reproduced within a closed bottle containing push-pins (Nohguchi, 2004). Experiments for tilted and layered case have also been conducted (Peacock, 2006). However quantitative measurements of liquid transport in these experiments have rarely been made. Here we show that such measurements are possible by analyzing the video images taken during such experiments. In addition, we show that a simple physical model is capable of explaining the time scales needed to expel the interstitial liquid. An experimental cell (cross section 22.0 mm x 99.4 mm, height 107.6 mm) is filled with a granular matter and water. The lower 33.0 mm consists of a two-layered granular medium, the upper layer consists of fine particles and the lower layer consists of coarse particles, with particle sizes of 0.05 mm and 0.2 mm, respectively. Since permeability depends on the square of the particle size, the upper layer becomes a low-permeability layer. We liquefy the cell by an impulsive vibration and study how the liquid migrates afterwards. We also vary the particle size combinations (upper layer: 0.05-0.15 mm, lower layer: 0.15-0.6 mm) and the thickness ratio of the 2 layers, and study how the time scale of the liquid migration depends on these changeable parameters. In a two-layered medium, we find that the pore water which originated from the bottom layer temporary accumulates at the interface of the two layers, and then ascends through the upper layer in the form of horizontal sheet or vertical channels. We find that these two different discharge styles are controlled by the permeability ratio of the two layers. We study the temporal change of the thicknesses of the two layers and find that there are three stages; 1: the slope of the upper surface is leveled by the impulse, 2: the pore water is discharged from the bottom layer and accumulates at the interface, after which it migrates upwards, 3: water discharge ends, and particles settle. We measured the relaxation time needed for the discharge and compaction to end. Because low-permeability layer inhibits pore water from rising, longer time is needed for a two-layer case compared to the one-layer case. When the particle size of the upper layer is about 1/3 or smaller than that of the lower layer, relaxation time becomes independent of the bottom particle size. We modeled the relaxation time by introducing the effective permeability of two-layered medium, and find that it explains the measurements well. References Nohguchi, Y., 2004, ICTAM04 Proceedings, Warsaw, Poland. Peacock, D. C. P., 2006, J. Geosci.Ed, 54, 550

Improved Root Normal Size Distributions for Liquid Atomization

DTIC Science & Technology

2015-11-01

Jackson, Primary Breakup of Round Aerated- Liquid Jets in Supersonic Crossflows, Atomization and Sprays, 16(6), 657-672, 2006 H. C. Simmons, The...Breakup in Liquid - Gas Mixing Layers, Atomization and Sprays, 1, 421-440, 1991 P.-K. Wu, L.-K. Tseng, and G. M. Faeth, Primary Breakup in Gas / Liquid ...Improved Root Normal Size Distributions for Liquid Atomization Distribution Statement A. Approved for public release; distribution is unlimited

Reflective liquid crystal light valve with hybrid field effect mode

NASA Technical Reports Server (NTRS)

Boswell, Donald D. (Inventor); Grinberg, Jan (Inventor); Jacobson, Alexander D. (Inventor); Myer, Gary D. (Inventor)

1977-01-01

There is disclosed a high performance reflective mode liquid crystal light valve suitable for general image processing and projection and particularly suited for application to real-time coherent optical data processing. A preferred example of the device uses a CdS photoconductor, a CdTe light absorbing layer, a dielectric mirror, and a liquid crystal layer sandwiched between indium-tin-oxide transparent electrodes deposited on optical quality glass flats. The non-coherent light image is directed onto the photoconductor; this reduces the impedance of the photoconductor, thereby switching the AC voltage that is impressed across the electrodes onto the liquid crystal to activate the device. The liquid crystal is operated in a hybrid field effect mode. It utilizes the twisted nematic effect to create a dark off-state (voltage off the liquid crystal) and the optical birefringence effect to create the bright on-state. The liquid crystal thus modulates the polarization of the coherent read-out or projection light responsively to the non-coherent image. An analyzer is used to create an intensity modulated output beam.

Ultrahigh performance heat spreader based on gas-liquid exfoliation boron nitride nanosheets.

PubMed

Ding, Jiheng; Zhao, Hongran; Wang, Qiaolei; Peng, Wanjun; Yu, Haibin

2017-11-24

Due to their high thermal conductivity and insulation performance, boron nitride nanosheets (BNNS) have great promise to fabricate thermal management equipment for application in power electronics. The liquid-phase exfoliation route has been regarded as the most commonly used approach to produce single and few-layered BNNS for many research fields. However, this process takes a long time, and the production yield is extremely low. In this work, an efficient technique to obtain few-layered (mostly < 5 layers), high-yield (∼33%), and plane-defect-free BNNS by the combination of liquid N 2 (L-N 2 ) gasification and liquid exfoliation was developed. The as-obtained BNNS suspensions could be vacuum filtered to make a thermal conductive film named a BNNS heat spreader which possessed a superior thermal conductivity of 61.2 W m -1 K -1 at room temperature. In addition, we also proved that the thermal conductivity of the BNNS heat spreader increased with the increase of density, creating an approach for fine tuning the thermal property of this heat spreader.

Low-Temperature Growth of Two-Dimensional Layered Chalcogenide Crystals on Liquid.

PubMed

Zhou, Yubing; Deng, Bing; Zhou, Yu; Ren, Xibiao; Yin, Jianbo; Jin, Chuanhong; Liu, Zhongfan; Peng, Hailin

2016-03-09

The growth of high-quality two-dimensional (2D) layered chalcogenide crystals is highly important for practical applications in future electronics, optoelectronics, and photonics. Current route for the synthesis of 2D chalcogenide crystals by vapor deposition method mainly involves an energy intensive high-temperature growth process on solid substrates, often suffering from inhomogeneous nucleation density and grain size distribution. Here, we first demonstrate a facile vapor-phase synthesis of large-area high-quality 2D layered chalcogenide crystals on liquid metal surface with relatively low surface energy at a growth temperature as low as ∼100 °C. Uniform and large-domain-sized 2D crystals of GaSe and GaxIn1-xSe were grown on liquid metal surface even supported on a polyimide film. As-grown 2D GaSe crystals have been fabricated to flexible photodetectors, showing high photoresponse and excellent flexibility. Our strategy of energy-sustainable low-temperature growth on liquid metal surface may open a route to the synthesis of high-quality 2D crystals of Ga-, In-, Bi-, Hg-, Pb-, or Sn-based chalcogenides and halides.

Ultrahigh performance heat spreader based on gas-liquid exfoliation boron nitride nanosheets

NASA Astrophysics Data System (ADS)

Ding, Jiheng; Zhao, Hongran; Wang, Qiaolei; Peng, Wanjun; Yu, Haibin

2017-11-01

Due to their high thermal conductivity and insulation performance, boron nitride nanosheets (BNNS) have great promise to fabricate thermal management equipment for application in power electronics. The liquid-phase exfoliation route has been regarded as the most commonly used approach to produce single and few-layered BNNS for many research fields. However, this process takes a long time, and the production yield is extremely low. In this work, an efficient technique to obtain few-layered (mostly < 5 layers), high-yield (˜33%), and plane-defect-free BNNS by the combination of liquid N2 (L-N2) gasification and liquid exfoliation was developed. The as-obtained BNNS suspensions could be vacuum filtered to make a thermal conductive film named a BNNS heat spreader which possessed a superior thermal conductivity of 61.2 W m-1 K-1 at room temperature. In addition, we also proved that the thermal conductivity of the BNNS heat spreader increased with the increase of density, creating an approach for fine tuning the thermal property of this heat spreader.

Prenucleation Induced by Crystalline Substrates

NASA Astrophysics Data System (ADS)

Men, H.; Fan, Z.

2018-04-01

Prenucleation refers to the phenomenon of atomic ordering in the liquid adjacent to the substrate/liquid interface at temperatures above the liquidus. In this paper, we have systematically investigated and holistically quantified the prenucleation phenomenon as a function of temperature and the lattice misfit between the substrate and the solid, using molecular dynamics (MD) simulations. Our results have confirmed that at temperatures above the liquidus, the atoms in the liquid at the interface may exhibit pronounced atomic ordering, manifested by atomic layering normal to the interface, in-plane atomic ordering parallel to the interface, and the formation of a 2-dimensional (2D) ordered structure (a few atomic layers in thickness) on the substrate surface. Holistic quantification of such atomic ordering at the interface has revealed that the atomic layering is independent of lattice misfit and is only slightly enhanced by reducing temperature while both in-plane atomic ordering and the formation of the 2D ordered structure are significantly enhanced by reducing the lattice misfit and/or temperature. This substrate-induced atomic ordering in the liquid may have a significant influence on the subsequent heterogeneous nucleation process.

Geological evidence for solid-state convection in Europa's ice shell.

PubMed

Pappalardo, R T; Head, J W; Greeley, R; Sullivan, R J; Pilcher, C; Schubert, G; Moore, W B; Carr, M H; Moore, J M; Belton, M J; Goldsby, D L

1998-01-22

The ice-rich surface of the jovian satellite Europa is sparsely cratered, suggesting that this moon might be geologically active today. Moreover, models of the satellite's interior indicate that tidal interactions with Jupiter might produce enough heat to maintain a subsurface liquid water layer. But the mechanisms of interior heat loss and resurfacing are currently unclear, as is the question of whether Europa has (or had at one time) a liquid water ocean. Here we report on the morphology and geological interpretation of distinct surface features-pits, domes and spots-discovered in high-resolution images of Europa obtained by the Galileo spacecraft. The features are interpreted as the surface manifestation of diapirs, relatively warm localized ice masses that have risen buoyantly through the subsurface. We find that the formation of the features can be explained by thermally induced solid-state convection within an ice shell, possibly overlying a liquid water layer. Our results are consistent with the possibility that Europa has a liquid water ocean beneath a surface layer of ice, but further tests and observations are needed to demonstrate this conclusively.

Geological evidence for solid-state convection in Europa's ice shell

USGS Publications Warehouse

Pappalardo, R.T.; Head, J.W.; Greeley, R.; Sullivan, R.J.; Pilcher, C.; Schubert, G.; Moore, W.B.; Carr, M.H.; Moore, Johnnie N.; Belton, M.J.S.; Goldsby, D.L.

1998-01-01

The ice-rich surface of the jovian satellite Europa is sparsely cratered, suggesting that this moon might be geologically active today. Moreover, models of the satellite's interior indicate that tidal interactions with Jupiter might produce enough heat to maintain a subsurface liquid water layer. But the mechanisms of interior heat loss and resurfacing are currently unclear, as is the question of whether Europa has (or had at one time) a liquid water ocean. Here we report on the morphology and geological interpretation of distinct surface features-pits, domes and spots-discovered in high-resolution images of Europa obtained by the Galileo spacecraft. The features are interpreted as the surface manifestation of diapirs, relatively warm localized ice masses that have risen buoyantly through the subsurface. We find that the formation of the features can be explained by thermally induced solid-state convection within an ice shell, possibly overlying a liquid water layer. Our results are consistent with the possibility that Europa has a liquid water ocean beneath a surface layer of ice, but further tests and observations are needed to demonstrate this conclusively.

Measuring Diffusion of Liquids by Common-Path Interferometry

NASA Technical Reports Server (NTRS)

Rashidnia, Nasser

2003-01-01

A method of observing the interdiffusion of a pair of miscible liquids is based on the use of a common-path interferometer (CPI) to measure the spatially varying gradient of the index refraction in the interfacial region in which the interdiffusion takes place. Assuming that the indices of refraction of the two liquids are different and that the gradient of the index of refraction of the liquid is proportional to the gradient in the relative concentrations of either liquid, the diffusivity of the pair of liquids can be calculated from the temporal variation of the spatial variation of the index of refraction. This method yields robust measurements and does not require precise knowledge of the indices of refraction of the pure liquids. Moreover, the CPI instrumentation is compact and is optomechanically robust by virtue of its common- path design. The two liquids are placed in a transparent rectangular parallelepiped test cell. Initially, the interface between the liquids is a horizontal plane, above which lies pure liquid 2 (the less-dense liquid) and below which lies pure liquid 1 (the denser liquid). The subsequent interdiffusion of the liquids gives rise to a gradient of concentration and a corresponding gradient of the index of refraction in a mixing layer. For the purpose of observing the interdiffusion, the test cell is placed in the test section of the CPI, in which a collimated, polarized beam of light from a low-power laser is projected horizontally through a region that contains the mixing layer.

Optofluidic lens actuated by laser-induced solutocapillary forces

NASA Astrophysics Data System (ADS)

Malyuk, A. Yu.; Ivanova, N. A.

2017-06-01

We demonstrate an adaptive liquid lens controlled by laser-induced solutocapillary forces. The liquid droplet serving as a lens is formed in a thin layer of binary liquid mixture by surface tension driven flows caused by the thermal action of laser irradiation. The shape of droplet, its aperture and the focal length are reversibly changed without hysteresis by varying the intensity of the laser beam. The focal length variation range of the droplet-lens lies in between infinity (a flat layer) to 15 mm (a curved interface). The droplet-lens is capable to adjust the in-plane lateral position in response to a displacement of the laser beam. The proposed laser controlled droplet-lens will enable to develop smart liquid optical devices, which can imitate the accommodation reflex and pupillary light reflex of the eye.

Variable convergence liquid layer implosions on the National Ignition Facility

NASA Astrophysics Data System (ADS)

Zylstra, A. B.; Yi, S. A.; Haines, B. M.; Olson, R. E.; Leeper, R. J.; Braun, T.; Biener, J.; Kline, J. L.; Batha, S. H.; Berzak Hopkins, L.; Bhandarkar, S.; Bradley, P. A.; Crippen, J.; Farrell, M.; Fittinghoff, D.; Herrmann, H. W.; Huang, H.; Khan, S.; Kong, C.; Kozioziemski, B. J.; Kyrala, G. A.; Ma, T.; Meezan, N. B.; Merrill, F.; Nikroo, A.; Peterson, R. R.; Rice, N.; Sater, J. D.; Shah, R. C.; Stadermann, M.; Volegov, P.; Walters, C.; Wilson, D. C.

2018-05-01

Liquid layer implosions using the "wetted foam" technique, where the liquid fuel is wicked into a supporting foam, have been recently conducted on the National Ignition Facility for the first time [Olson et al., Phys. Rev. Lett. 117, 245001 (2016)]. We report on a series of wetted foam implosions where the convergence ratio was varied between 12 and 20. Reduced nuclear performance is observed as convergence ratio increases. 2-D radiation-hydrodynamics simulations accurately capture the performance at convergence ratios (CR) ˜ 12, but we observe a significant discrepancy at CR ˜ 20. This may be due to suppressed hot-spot formation or an anomalous energy loss mechanism.

Wetting and spreading at the molecular scale

NASA Technical Reports Server (NTRS)

Koplik, Joel; Banavar, Jayanth R.

1994-01-01

We have studied the microscopic aspects of the spreading of liquid drops on a solid surface by molecular dynamics simulations of coexisting three-phase Lennard-Jones systems of liquid, vapor and solid. We consider both spherically symmetric atoms and chain-like molecules, and a range of interaction strengths. As the attraction between liquid and solid increases we observed a smooth transition in spreading regimes, from partial to complete to terraced wetting. In the terraced case, where distinct monomolecular layers spread with different velocities, the layers are ordered but not solid, with qualitative behavior resembling recent experimental findings, but with interesting differences in the spreading rate.

Paintable band-edge liquid crystal lasers.

PubMed

Gardiner, Damian J; Morris, Stephen M; Hands, Philip J W; Mowatt, Carrie; Rutledge, Rupert; Wilkinson, Timothy D; Coles, Harry J

2011-01-31

In this paper we demonstrate photonic band-edge laser emission from emulsion-based polymer dispersed liquid crystals. The lasing medium consists of dye-doped chiral nematic droplets dispersed within a polymer matrix that spontaneously align as the film dries. Such lasers can be easily formed on single substrates with no alignment layers. The system combines the self-organizing periodic structure of chiral nematic liquid crystals with the simplicity of the emulsion procedure so as to produce a material that retains the emission characteristics of band-edge lasers yet can be readily coated. Sequential and stacked layers demonstrate the possibility of achieving simultaneous multi-wavelength laser output from glass, metallic, and flexible substrates.

Understanding the stability of surface nanobubbles.

PubMed

Wang, Shuo; Liu, Minghuan; Dong, Yaming

2013-05-08

Surface nanobubbles emerging at solid-liquid interfaces show extreme stability. In this paper, the stability of surface nanobubbles in degassed water is discussed and investigated by AFM. The result demonstrates that surface nanobubbles are kinetically stable and the liquid/gas interface is gas impermeable. The force modulation experiment further proves that there is a layer coating on nanobubbles. These critical properties suggest that surface nanobubbles may be stabilized by a layer which has a great diffusive resistance.

Tethered catalysts for the hydration of carbon dioxide

DOEpatents

Valdez, Carlos A; Satcher, Jr., Joe H; Aines, Roger D; Wong, Sergio E; Baker, Sarah E; Lightstone, Felice C; Stolaroff, Joshuah K

2014-11-04

A system is provided that substantially increases the efficiency of CO.sub.2 capture and removal by positioning a catalyst within an optimal distance from the air-liquid interface. The catalyst is positioned within the layer determined to be the highest concentration of carbon dioxide. A hydrophobic tether is attached to the catalyst and the hydrophobic tether modulates the position of the catalyst within the liquid layer containing the highest concentration of carbon dioxide.

Alkali metal-refractory metal biphase electrode for AMTEC

NASA Technical Reports Server (NTRS)

Williams, Roger M. (Inventor); Bankston, Clyde P. (Inventor); Cole, Terry (Inventor); Khanna, Satish K. (Inventor); Jeffries-Nakamura, Barbara (Inventor); Wheeler, Bob L. (Inventor)

1989-01-01

An electrode having increased output with slower degradation is formed of a film applied to a beta-alumina solid electrolyte (BASE). The film comprises a refractory first metal M.sup.1 such as a platinum group metal, suitably platinum or rhodium, capable of forming a liquid or a strong surface adsorption phase with sodium at the operating temperature of an alkali metal thermoelectric converter (AMTEC) and a second refractory metal insoluble in sodium or the NaM.sup.1 liquid phase such as a Group IVB, VB or VIB metal, suitably tungsten, molybdenum, tantalum or niobium. The liquid phase or surface film provides fast transport through the electrode while the insoluble refractory metal provides a structural matrix for the electrode during operation. A trilayer structure that is stable and not subject to deadhesion comprises a first, thin layer of tungsten, an intermediate co-deposited layer of tungsten-platinum and a thin surface layer of platinum.

Liquid exfoliation of solvent-stabilized few-layer black phosphorus for applications beyond electronics

PubMed Central

Hanlon, Damien; Backes, Claudia; Doherty, Evie; Cucinotta, Clotilde S.; Berner, Nina C.; Boland, Conor; Lee, Kangho; Harvey, Andrew; Lynch, Peter; Gholamvand, Zahra; Zhang, Saifeng; Wang, Kangpeng; Moynihan, Glenn; Pokle, Anuj; Ramasse, Quentin M.; McEvoy, Niall; Blau, Werner J.; Wang, Jun; Abellan, Gonzalo; Hauke, Frank; Hirsch, Andreas; Sanvito, Stefano; O'Regan, David D.; Duesberg, Georg S.; Nicolosi, Valeria; Coleman, Jonathan N.

2015-01-01

Few-layer black phosphorus (BP) is a new two-dimensional material which is of great interest for applications, mainly in electronics. However, its lack of environmental stability severely limits its synthesis and processing. Here we demonstrate that high-quality, few-layer BP nanosheets, with controllable size and observable photoluminescence, can be produced in large quantities by liquid phase exfoliation under ambient conditions in solvents such as N-cyclohexyl-2-pyrrolidone (CHP). Nanosheets are surprisingly stable in CHP, probably due to the solvation shell protecting the nanosheets from reacting with water or oxygen. Experiments, supported by simulations, show reactions to occur only at the nanosheet edge, with the rate and extent of the reaction dependent on the water/oxygen content. We demonstrate that liquid-exfoliated BP nanosheets are potentially useful in a range of applications from ultrafast saturable absorbers to gas sensors to fillers for composite reinforcement. PMID:26469634

Self-organization processes and topological defects in nanolayers in a nematic liquid crystal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chuvyrov, A. N.; Girfanova, F. M.; Mal'tsev, I. S.

Atomic force microscopy is used to study the self-organization processes that occur during the formation of topological defects in nanomolecular layers in a nematic liquid crystal with the homeotropic orientation of its molecules with respect to the substrate. In this case, a smectic monolayer with a thickness of one molecule length (about 2.2 nm) forms on the substrate, and a nanomolecular layer of a nematic liquid crystal forms above this monolayer. In such virtually two-dimensional layers, numerous different nanoclusters, namely, hut structures, pyramids, raft structures with symmetry C{sub nm} (where n = 2, 4, 5, 6, 7, ?, {infinity}), cones,more » and nanopools, form [1]. They have a regular shape close to the geometry of solid crystals. Modulated linear structures and topological point defects appear spontaneously in the nanopools and raft structures.« less

Caractérisation de l'augmentation des transferts thermiques dans une couche de liquide diélectrique soumise à une injection unipolaire de charges électriques

NASA Astrophysics Data System (ADS)

Traoré, Philippe; Koulova-Nenova, D.; Romat, H.; Perez, A.

2009-03-01

The electro-thermo-convective flow in a horizontal dielectric liquid layer placed between two electrodes and subjected to an injection of electric charges from one of the electrodes and at the same time to a thermal gradient is studied numerically. We consider the case of a strong charge injection in order to only take into account the Coulomb force disregarding the dielectric forces, from above and below the layer. The effect of the action of both electric and thermal fields on the dielectric liquid layer is analyzed and the behavior of the flow when these fields compete or cooperate is studied. It is demonstrated that the electrically induced convection enhances the heat transfer. To cite this article: Ph. Traoré et al., C. R. Mecanique 337 (2009).

Analysis of Meteorological Data Obtained During Flight in a Supercooled Stratiform Cloud of High Liquid-Water Content

NASA Technical Reports Server (NTRS)

Perkins, Porter J.; Kline, Dwight B.

1951-01-01

Flight icing-rate data obtained in a dense and. abnormally deep supercooled stratiform cloud system indicated the existence of liquid-water contents generally exceeding values in amount and extent previously reported over the midwestern sections of the United States. Additional information obtained during descent through a part of the cloud system indicated liquid-water contents that significantly exceeded theoretical values, especially near the middle of the cloud layer.. The growth of cloud droplets to sizes that resulted in sedimentation from the upper portions of the cloud is considered to be a possible cause of the high water contents near the center of the cloud layer. Flight measurements of the vertical temperature distribution in the cloud layer indicated a rate of change of temperature with altitude exceeding that of the moist adiabatic lapse rate. This excessive rate of change is considered to have contributed to the severity of the condition.

A molecular dynamics study of liquid layering and thermal conductivity enhancement in nanoparticle suspensions

NASA Astrophysics Data System (ADS)

Paul, J.; Madhu, A. K.; Jayadeep, U. B.; Sobhan, C. B.; Peterson, G. P.

2018-03-01

Liquid layering is considered to be one of the factors contributing to the often anomalous enhancement in thermal conductivity of nanoparticle suspensions. The extent of this layering was found to be significant at lower particle sizes, as reported in an earlier work by the authors. In continuation to that work, an investigation was conducted to better understand the fundamental parameters impacting the reported anomalous enhancement in thermal conductivity of nanoparticle suspensions (nanofluids), utilizing equilibrium molecular dynamics simulations in a copper-argon system. Nanofluids containing nanoparticles of size less than 6 nm were investigated and studied analytically. The heat current auto-correlation function in the Green-Kubo formulation for thermal conductivity was decomposed into self-correlations and cross-correlations of different species and the kinetic, potential, collision and enthalpy terms of the dominant portion of the heat current vector. The presence of liquid layering around the nanoparticle was firmly established through simulations that show the dominant contribution of Ar-Ar self-correlation and the trend displayed by the kinetic-potential cross-correlation within the argon species.

A photofunctional bottom-up bis(dipyrrinato)zinc(II) complex nanosheet

PubMed Central

Sakamoto, Ryota; Hoshiko, Ken; Liu, Qian; Yagi, Toshiki; Nagayama, Tatsuhiro; Kusaka, Shinpei; Tsuchiya, Mizuho; Kitagawa, Yasutaka; Wong, Wai-Yeung; Nishihara, Hiroshi

2015-01-01

Two-dimensional polymeric nanosheets have recently gained much attention, particularly top-down nanosheets such as graphene and metal chalcogenides originating from bulk-layered mother materials. Although molecule-based bottom-up nanosheets manufactured directly from molecular components can exhibit greater structural diversity than top-down nanosheets, the bottom-up nanosheets reported thus far lack useful functionalities. Here we show the design and synthesis of a bottom-up nanosheet featuring a photoactive bis(dipyrrinato)zinc(II) complex motif. A liquid/liquid interfacial synthesis between a three-way dipyrrin ligand and zinc(II) ions results in a multi-layer nanosheet, whereas an air/liquid interfacial reaction produces a single-layer or few-layer nanosheet with domain sizes of >10 μm on one side. The bis(dipyrrinato)zinc(II) metal complex nanosheet is easy to deposit on various substrates using the Langmuir–Schäfer process. The nanosheet deposited on a transparent SnO2 electrode functions as a photoanode in a photoelectric conversion system, and is thus the first photofunctional bottom-up nanosheet. PMID:25831973

On Multiple-Layered Vortices

NASA Technical Reports Server (NTRS)

Rossow, Vernon J.

2011-01-01

As part of an ongoing effort to find ways to make vortex flow fields decompose more quickly, photographs and observations are presented of vortex flow fields that indicate the presence of multiple layers of fluid rotating about a common axis. A survey of the literature indicates that multiple-layered vortices form in waterspouts, tornadoes and lift-generated vortices of aircraft. An explanation for the appearance of multiple-layered structures in vortices is suggested. The observations and data presented are intended to improve the understanding of the formation and persistence of vortex flow fields.

Fluid transition layer between rigid solute and liquid solvent: is there depletion or enrichment?

PubMed

Djikaev, Yuri S; Ruckenstein, Eli

2016-03-21

The fluid layer between solute and liquid solvent is studied by combining the density functional theory with the probabilistic hydrogen bond model. This combination allows one to obtain the equilibrium distribution of fluid molecules, taking into account the hydrogen bond contribution to the external potential whereto they are subjected near the solute. One can find the effective width of the fluid solvent-solute transition layer and fluid average density in that layer, and determine their dependence on temperature, solvent-solute affinity, vicinal hydrogen bond (hb) energy alteration ratio, and solute radius. Numerical calculations are performed for the solvation of a plate and spherical solutes of four different radii in two model solvents (associated liquid and non-associated one) in the temperature range from 293 K to 333 K for various solvent-solute affinities and hydrogen bond energy alteration ratios. The predictions of our model for the effective width and average density of the transition layer are consistent with experiments and simulations. The small-to-large crossover lengthscale for hydrophobic hydration is expected to be about 3-5 nm. Remarkably, characterizing the transition layer with the average density, one can observe that for small hydrophobes, the transition layer becomes enriched with rather than depleted of fluid when the solvent-solute affinity and hb-energy alteration ratio become large enough. The boundary values of solvent-solute affinity and hb-energy alteration ratio, needed for the "depletion-to-enrichment" crossover (in the smoothed density sense), are predicted to decrease with increasing temperature.

3 V omni-directionally stretchable one-body supercapacitors based on a single ion-gel matrix and carbon nanotubes.

PubMed

Kim, Wonbin; Kim, Woong

2016-06-03

Stretchable supercapacitors often have laminated structures consisting of electrode, electrolyte, and supporting layers. Since the layers are likely to be composed of different materials, delamination is a major cause of failure upon stretching. In this study, we demonstrate delamination-free stretchable supercapacitors where all the component layers are prepared with a single matrix, which is composed of a polymer, poly(vinylidene fluoride-hexafluoropropylene) and an ionic liquid, 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide. Since the ionic liquid in the composite plays a role as both an electrolyte and a plasticizer, this composite can be used as an electrolyte and a supporting layer in the stretchable supercapacitor. The electrode layer can be fabricated by incorporating carbon nanotubes in the common matrix. Then, all the layers can be seamlessly fused into one body by dissolving the surface of the composite with acetone, which evaporates after the integration, leaving no borders between the layers. This one-body stretchable supercapacitor not only has high durability against repetitive stretches but also is stretchable in all directions. This feature clearly distinguishes them from conventional stretchable supercapacitors fabricated using buckled structures, which are stretchable only in one or two directions. Moreover, this supercapacitor has high cell voltage (∼3 V) owing to the ionic liquid-based gel electrolytes. Our demonstration of isotropically stretchable high-durability supercapacitors may have a great implication in the development of stretchable energy storage devices for real applications.

Impurity effects on ionic-liquid-based supercapacitors

DOE PAGES

Liu, Kun; Lian, Cheng; Henderson, Douglas; ...

2016-12-27

Small amounts of an impurity may affect the key properties of an ionic liquid and such effects can be dramatically amplified when the electrolyte is under confinement. Here the classical density functional theory is employed to investigate the impurity effects on the microscopic structure and the performance of ionic-liquid-based electrical double-layer capacitors, also known as supercapacitors. Using a primitive model for ionic species, we study the effects of an impurity on the double layer structure and the integral capacitance of a room temperature ionic liquid in model electrode pores and find that an impurity strongly binding to the surface ofmore » a porous electrode can significantly alter the electric double layer structure and dampen the oscillatory dependence of the capacitance with the pore size of the electrode. Meanwhile, a strong affinity of the impurity with the ionic species affects the dependence of the integral capacitance on the pore size. Up to 30% increase in the integral capacitance can be achieved even at a very low impurity bulk concentration. As a result, by comparing with an ionic liquid mixture containing modified ionic species, we find that the cooperative effect of the bounded impurities is mainly responsible for the significant enhancement of the supercapacitor performance.« less

Nonintrusive measurement of the liquid refractive index by using properties of the cuvette wall.

PubMed

Xu, Ming; Ren, Junpeng; Miao, Runcai; Zhang, Zongquan

2016-10-01

We present a method of nonintrusive measurement of the refractive index of a liquid in a glass cuvette, which uses some optical properties of the cuvette wall and the principle of total internal reflection. By coating a transmission-scattering paint layer on the outer surface of the cuvette, we transform an incident laser beam into a transmitted scattered light. When the transmitted scattered light reaches the interface between the container wall and the liquid inside, the light beams satisfying the condition of total internal reflection are reflected to the coating layer, automatically forming a circular dark pattern that is related to the refractive index of the liquid. Based on an analytic relation between the diameter of the circular dark pattern and the refractive index of the liquid, we devised a method of in situ nonintrusive refractive index measurement. We tested the effect of several parameters on the measuring accuracy and found that the optimal thickness of the transmission-scattering layer is in the range of 50-70 μm, and the aperture of the diaphragm should be in the range of 0.7-1.0 mm. We measured the refractive indices of ethanol, Coca Cola, and red wine, and achieved an accuracy of ±3×10^-4  RIU (refractive index unit).

Suspended-slurry reactor

DOEpatents

None

2016-03-22

An apparatus for generating a large volume of gas from a liquid stream is disclosed. The apparatus includes a first channel through which the liquid stream passes. The apparatus also includes a layer of catalyst particles suspended in a solid slurry for generating gas from the liquid stream. The apparatus further includes a second channel through which a mixture of converted liquid and generated gas passes. A heat exchange channel heats the liquid stream. A wicking structure located in the second channel separates the gas generated from the converted liquid.

Liquid crystalline composites containing phyllosilicates

DOEpatents

Chaiko,; David, J [Naperville, IL

2007-05-08

The present invention provides barrier films having reduced gas permeability for use in packaging and coating applications. The barrier films comprise an anisotropic liquid crystalline composite layer formed from phyllosilicate-polymer compositions. Phyllosilicate-polymer liquid crystalline compositions of the present invention can contain a high percentage of phyllosilicate while remaining transparent. Because of the ordering of the particles in the liquid crystalline composite, barrier films comprising liquid crystalline composites are particularly useful as barriers to gas transport.

Liquid water- and heat-resistant hybrid perovskite photovoltaics via an inverted ALD oxide electron extraction layer design

DOE PAGES

Kim, In Soo; Cao, Duyen H.; Buchholz, D. Bruce; ...

2016-11-09

Despite rapid advances in conversion efficiency (>22%), the environmental stability of perovskite solar cells remains a substantial barrier to commercialization. Here, we show a significant improvement in the stability of inverted perovskite solar cells against liquid water and high operating temperature (100 °C) by integrating an ultrathin amorphous oxide electron extraction layer via atomic layer deposition (ALD). Here, these unencapsulated inverted devices exhibit a stable operation over at least 10 h when subjected to high thermal stress (100 °C) in ambient environments, as well as upon direct contact with a droplet of water without further encapsulation.

Parametric Excitation of Marangoni Instability in a Heated Thin Layer Covered by Insoluble Surfactant

NASA Astrophysics Data System (ADS)

Mikishev, Alexander B.; Nepomnyashchy, Alexander A.

2018-05-01

The paper presents the analysis of the impact of vertical periodic vibrations on the long-wavelength Marangoni instability in a liquid layer with poorly conducting boundaries in the presence of insoluble surfactant on the deformable gas-liquid interface. The layer is subject to a uniform transverse temperature gradient. Linear stability analysis is performed in order to find critical values of Marangoni numbers for both monotonic and oscillatory instability modes. Longwave asymptotic expansions are used. At the leading order, the critical values are independent on vibration parameters; at the next order of approximation we obtained the rise of stability thresholds due to vibration.

Focal Conic Stacking in Smectic A Liquid Crystals: Smectic Flower and Apollonius Tiling

PubMed Central

Meyer, Claire; Cunff, Loic Le; Belloul, Malika; Foyart, Guillaume

2009-01-01

We investigate two different textures of smectic A liquid crystals. These textures are particularly symmetric when they are observed at crossed polars optical microscopy. For both textures, a model has been made in order to examine the link between the defective macroscopic texture and the microscopic disposition of the layers. We present in particular in the case of some hexagonal tiling of circles (similar to the Apollonius tiling) some numeric simulation in order to visualize the smectic layers. We discuss of the nature of the smectic layers, which permit to assure their continuity from one focal conic domain to another adjacent one.

Germanium layers grown by zone thermal crystallization from a discrete liquid source

NASA Astrophysics Data System (ADS)

Yatsenko, A. N.; Chebotarev, S. N.; Lozovskii, V. N.; Mohamed, A. A. A.; Erimeev, G. A.; Goncharova, L. M.; Varnavskaya, A. A.

2017-11-01

It is proposed and investigated a method for growing thin uniform germanium layers onto large silicon substrates. The technique uses the hexagonally arranged local sources filled with liquid germanium. Germanium evaporates on very close substrate and in these conditions the residual gases vapor pressure highly reduces. It is shown that to achieve uniformity of the deposited layer better than 97% the critical thickness of the vacuum zone must be equal to l cr = 1.2 mm for a hexagonal arranged system of round local sources with the radius of r = 0.75 mm and the distance between the sources of h = 0.5 mm.

Measurement method for the refractive index of thick solid and liquid layers.

PubMed

Santić, Branko; Gracin, Davor; Juraić, Krunoslav

2009-08-01

A simple method is proposed for the refractive index measurement of thick solid and liquid layers. In contrast to interferometric methods, no mirrors are used, and the experimental setup is undemanding and simple. The method is based on the variation of transmission caused by optical interference within the layer as a function of incidence angle. A new equation is derived for the positions of the interference extrema versus incidence angle. Scattering at the surfaces and within the sample, as well as weak absorption, do not play important roles. The method is illustrated by the refractive index measurements of sapphire, window glass, and water.

Interactions Between Chlorinated Waste Solvents and Clay Minerals in Low Permeability Subsurface Layers

NASA Astrophysics Data System (ADS)

Ayral, D.; Otero-Diaz, M.; Demond, A. H.

2014-12-01

Waste organic contaminants stored in low permeability subsurface layers serve as long-term sources for dissolved phase contaminant plumes. These layers may have a different mineralogical make up than the surrounding geologic media; specifically, they may be characterized by a high clay content. Although these layers are often considered inert, interactions may occur between the clay minerals and the waste liquids that may influence transport. Measurements of the basal spacing of Na-montmorillonite in contact with pure chlorinated organic liquids such as trichloroethylene (TCE) showed that it is similar to that with water; however, its basal spacing in contact with waste chlorinated liquids was reduced, leading to cracking. In fact, the basal spacing in contact with the waste chlorinated liquids was closer to that in contact with air than in contact with water. The observation that contact with pure organic liquids did not cause cracking, but contact with chlorinated wastes obtained from the field did, suggests that other components of the waste are critical to the basal spacing reduction process. Screening experiments indicated that the presence of a binary mixture of surfactants, a nonionic and an anionic surfactant, in the chlorinated solvent were necessary to cause the cracking at the same rate and magnitude as the chlorinated wastes obtained from the field. Fourier transform infrared (FT-IR) spectroscopy measurements suggest that the mixture alters the adsorbed water OH-bending band, implying a displacement of adsorbed water. Coupling these results with sorption and x-ray diffraction (XRD) measurements, a hypothesis of component conformation in the clay interlayer space that leads to cracking can be constructed.

Terminal velocity of liquids and granular materials dispersed by a high explosive

NASA Astrophysics Data System (ADS)

Loiseau, J.; Pontalier, Q.; Milne, A. M.; Goroshin, S.; Frost, D. L.

2018-05-01

The explosive dispersal of a layer of solid particles or a layer of liquid surrounding a spherical high-explosive charge generates a turbulent, multiphase flow. Shock compression of the material layer during the initial acceleration may partially consolidate the material, leading to the formation of jet-like structures when the layer fragments and sheds particles upon release. Similarly, release of a shock-compressed liquid shell causes the nucleation of cavitation sites, leading to the radial breakup of the shell and the formation of jets upon expansion. In the current study, a wide variety of granular materials and liquids were explosively dispersed. The maximum terminal jet tip or shell velocity was measured using high-speed videography. Charges were constructed using thin-walled glass bulbs of various diameters and contained a central C-4 charge surrounded by the material to be dispersed. This permitted variation of the ratio of material mass to charge mass ( M/ C) from 4 to 300. Results indicated that material velocity broadly correlates with predictions of the Gurney model. For liquids, the terminal velocity was accurately predicted by the Gurney model. For granular materials, Gurney over-predicted the terminal velocity by 25-60%, depending on the M/ C ratio, with larger M/ C values exhibiting larger deficits. These deficits are explained by energy dissipation during the collapse of voids in the granular material bed. Velocity deficits were insensitive to the degree of jetting and granular material properties. Empirical corrections to the Gurney model are presented with improved agreement with the dry powder experimental velocities.

Terminal velocity of liquids and granular materials dispersed by a high explosive

NASA Astrophysics Data System (ADS)

Loiseau, J.; Pontalier, Q.; Milne, A. M.; Goroshin, S.; Frost, D. L.

2018-04-01

The explosive dispersal of a layer of solid particles or a layer of liquid surrounding a spherical high-explosive charge generates a turbulent, multiphase flow. Shock compression of the material layer during the initial acceleration may partially consolidate the material, leading to the formation of jet-like structures when the layer fragments and sheds particles upon release. Similarly, release of a shock-compressed liquid shell causes the nucleation of cavitation sites, leading to the radial breakup of the shell and the formation of jets upon expansion. In the current study, a wide variety of granular materials and liquids were explosively dispersed. The maximum terminal jet tip or shell velocity was measured using high-speed videography. Charges were constructed using thin-walled glass bulbs of various diameters and contained a central C-4 charge surrounded by the material to be dispersed. This permitted variation of the ratio of material mass to charge mass (M/C) from 4 to 300. Results indicated that material velocity broadly correlates with predictions of the Gurney model. For liquids, the terminal velocity was accurately predicted by the Gurney model. For granular materials, Gurney over-predicted the terminal velocity by 25-60%, depending on the M/C ratio, with larger M/C values exhibiting larger deficits. These deficits are explained by energy dissipation during the collapse of voids in the granular material bed. Velocity deficits were insensitive to the degree of jetting and granular material properties. Empirical corrections to the Gurney model are presented with improved agreement with the dry powder experimental velocities.

Metastable State during Melting and Solid-Solid Phase Transition of [CnMim][NO3] (n = 4-12) Ionic Liquids by Molecular Dynamics Simulation.

PubMed

Cao, Wudi; Wang, Yanting; Saielli, Giacomo

2018-01-11

We simulate the heating process of ionic liquids [C n Mim][NO 3 ] (n = 4, 6, 8, 10, 12), abbreviated as C n , by means of molecular dynamics (MD) simulation starting from a manually constructed triclinic crystal structure composed of polar layers containing anions and cationic head groups and nonpolar regions in between containing cationic alkyl side chains. During the heating process starting from 200 K, each system undergoes first a solid-solid phase transition at a lower temperature, and then a melting phase transition at a higher temperature to an isotropic liquid state (C 4 , C 6 , and C 8 ) or to a liquid crystal state (C 10 and C 12 ). After the solid-solid phase transition, all systems keep the triclinic space symmetry, but have a different set of lattice constants. C 4 has a more significant structural change in the nonpolar regions which narrows the layer spacing, while the layer spacings of other systems change little, which can be qualitatively understood by considering that the contribution of the effective van der Waals interaction in the nonpolar regions (abbreviated as EF1) to free energy becomes stronger with increasing side-chain length, and at the same time the contribution of the effective electrostatic interaction in the polar layers (abbreviated as EF2) to free energy remains almost the same. The melting phase transitions of all systems except C 6 are found to be a two-step process with an intermediate metastable state appeared during the melting from the crystal state to the liquid or liquid crystal state. Because the contribution of EF2 to the free energy is larger than EF1, the metastable state of C 4 has the feature of having higher ordered polar layers and lower ordered side-chain orientation. By contrast, C 8 -C 12 have the feature of having lower ordered polar layers and higher ordered side-chain orientation, because for these systems, the contribution of EF2 to the free energy is smaller than EF1. No metastable state is found for C 6 because the free-energy contribution of EF1 is balanced with EF2.

Lightweight Thermal Insulation for a Liquid-Oxygen Tank

NASA Technical Reports Server (NTRS)

Willen, G. Scott; Lock, Jennifer; Nieczkoski, Steve

2005-01-01

A proposed lightweight, reusable thermal-insulation blanket has been designed for application to a tank containing liquid oxygen, in place of a non-reusable spray-on insulating foam. The blanket would be of the multilayer-insulation (MLI) type and equipped with a pressure-regulated nitrogen purge system. The blanket would contain 16 layers in two 8-layer sub-blankets. Double-aluminized polyimide 0.3 mil (.0.008 mm) thick was selected as a reflective shield material because of its compatibility with oxygen and its ability to withstand ionizing radiation and high temperature. The inner and outer sub-blanket layers, 1 mil (approximately equals 0.025 mm) and 3 mils (approximately equals 0.076 mm) thick, respectively, would be made of the double-aluminized polyimide reinforced with aramid. The inner and outer layers would provide structural support for the more fragile layers between them and would bear the insulation-to-tank attachment loads. The layers would be spaced apart by lightweight, low-thermal-conductance netting made from polyethylene terephthalate.

Effects of Monomer Structure on Their Organization and Polymerization in a Smectic Liquid Crystal

PubMed

Guymon; Hoggan; Clark; Rieker; Walba; Bowman

1997-01-03

Photopolymerizable diacrylate monomers dissolved in fluid-layer smectic A and smectic C liquid crystal (LC) hosts exhibited significant spatial segregation and orientation that depend strongly on monomer structure. Small, flexible monomers such as 1,6-hexanediol diacrylate (HDDA) oriented parallel to the smectic layers and intercalated, whereas rod-shaped mesogen-like monomers such as 1,4-di-(4-(6-acryloyloxyhexyloxy)benzoyloxy)-2-methylbenzene (C6M) oriented normal to the smectic layers and collected within them. Such spatial segregation caused by the smectic layering dramatically enhanced photopolymerization rates; for HDDA, termination rates were reduced, whereas for C6M, both the termination and propagation rates were increased. These polymerization precursor structures suggest novel materials-design paradigms for gel LCs and nanophase-separated polymer systems.

Comparison of the Effect of Horizontal Vibrations on Interfacial Waves in a Two-Layer System of Inviscid Liquids to Effective Gravity Inversion

NASA Astrophysics Data System (ADS)

Pimenova, Anastasiya V.; Goldobin, Denis S.; Lyubimova, Tatyana P.

2018-02-01

We study the waves at the interface between two thin horizontal layers of immiscible liquids subject to high-frequency tangential vibrations. Nonlinear governing equations are derived for the cases of two- and three-dimensional flows and arbitrary ratio of layer thicknesses. The derivation is performed within the framework of the long-wavelength approximation, which is relevant as the linear instability of a thin-layers system is long-wavelength. The dynamics of equations is integrable and the equations themselves can be compared to the Boussinesq equation for the gravity waves in shallow water, which allows one to compare the action of the vibrational field to the action of the gravity and its possible effective inversion.

Online-LASIL: Laser Ablation of Solid Samples in Liquid with online-coupled ICP-OES detection for direct determination of the stoichiometry of complex metal oxide thin layers.

PubMed

Bonta, Maximilian; Frank, Johannes; Taibl, Stefanie; Fleig, Jürgen; Limbeck, Andreas

2018-02-13

Advanced materials such as complex metal oxides are used in a wide range of applications and have further promising perspectives in the form of thin films. The exact chemical composition essentially influences the electronic properties of these materials which makes correct assessment of their composition necessary. However, due to high chemical resistance and in the case of thin films low absolute analyte amounts, this procedure is in most cases not straightforward and extremely time-demanding. Commonly applied techniques either lack in ease of use (i.e., solution-based analysis with preceding sample dissolution), or adequately accurate quantification (i.e., solid sampling techniques). An analysis approach which combines the beneficial aspects of solution-based analysis as well as direct solid sampling is Laser Ablation of a Sample in Liquid (LASIL). In this work, it is shown that the analysis of major as well as minor sample constituents is possible using a novel online-LASIL setup, allowing sample analysis without manual sample handling after placing it in an ablation chamber. Strontium titanate (STO) thin layers with different compositions were analyzed in the course of this study. Precision of the newly developed online-LASIL method is comparable to conventional wet chemical approaches. With only about 15-20 min required for the analysis per sample, time demand is significantly reduced compared to often necessary fusion procedures lasting multiple hours. Copyright © 2017 Elsevier B.V. All rights reserved.

Low voltage electrowetting lenticular lens by using multilayer dielectric structure

NASA Astrophysics Data System (ADS)

Lee, Junsik; Kim, Junoh; Kim, Cheoljoong; Shin, Dooseub; Koo, Gyohyun; Sim, Jee Hoon; Won, Yong Hyub

2017-02-01

Lenticular type multi-view display is one of the most popular ways for implementing three dimensional display. This method has a simple structure and exhibits a high luminance. However, fabricating the lenticular lens is difficult because it requires optically complex calculations. 2D-3D conversion is also impossible due to the fixed shape of the lenticular lens. Electrowetting based liquid lenticular lens has a simple fabrication process compared to the solid lenticular lens and the focal length of the liquid lenticular lens can be changed by applying the voltage. 3D and 2D images can be observed with a convex and a flat lens state respectively. Despite these advantages, the electrowetting based liquid lenticular lens demands high driving voltage and low breakdown voltage with a single dielectric layer structure. A certain degree of thickness of the dielectric layer is essential for a uniform operation and a low degradation over time. This paper presents multilayer dielectric structure which results in low driving voltage and the enhanced dielectric breakdown. Aluminum oxide (Al2O3), silicon oxide (SiO2) and parylene C were selected as the multilayer insulators. The total thickness of the dielectric layer of all samples was the same. This method using the multilayer dielectric structure can achieve the lower operating voltage than when using the single dielectric layer. We compared the liquid lenticular lens with three kinds of the multilayer dielectric structure to one with the parylene C single dielectric layer in regard to operational characteristics such as the driving voltage and the dielectric breakdown.

Faraday instability-based micro droplet ejection for inhalation drug delivery

PubMed Central

Tsai, C.S.; Mao, R.W.; Lin, S.K.; Zhu, Y.; Tsai, S.C.

2014-01-01

We report here the technology and the underlying science of a new device for inhalation (pulmonary) drug delivery which is capable of fulfilling needs unmet by current commercial devices. The core of the new device is a centimeter-size clog-free silicon-based ultrasonic nozzle with multiple Fourier horns in resonance at megahertz (MHz) frequency. The dramatic resonance effect among the multiple horns and high growth rate of the MHz Faraday waves excited on a medicinal liquid layer together facilitate ejection of monodisperse droplets of desirable size range (2–5 µm) at low electrical drive power (<1.0 W). The small nozzle requiring low drive power has enabled realization of a pocket-size (8.6 × 5.6 × 1.5 cm3) ultrasonic nebulizer. A variety of common pulmonary drugs have been nebulized using the pocket-size unit with desirable aerosol sizes and output rate. These results clearly provide proof-of-principle for the new device and confirm its potential for commercialization. PMID:25045720

Surface structure evolution in a homologous series of ionic liquids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Haddad, Julia; Pontoni, Diego; Murphy, Bridget M.

Interfaces of room temperature ionic liquids (RTILs) are important for both applications and basic science and are therefore intensely studied. However, the evolution of their interface structure with the cation’s alkyl chain length n from Coulomb to van der Waals interaction domination has not yet been studied for even a single broad homologous RTIL series. We present in this paper such a study of the liquid–air interface for n = 2 to 22, using angstrom-resolution X-ray methods. For n < 6, a typical “simple liquid” monotonic surface-normal electron density profile ρ e more » ( z ) is obtained, like those of water and organic solvents. For n > 6, increasingly more pronounced nanoscale self-segregation of the molecules’ charged moieties and apolar chains yields surface layering with alternating regions of headgroups and chains. The layering decays into the bulk over a few, to a few tens, of nanometers. The layering periods and decay lengths, their linear n dependence, and slopes are discussed within two models, one with partial-chain interdigitation and the other with liquid-like chains. No surface-parallel long-range order is found within the surface layer. For n = 22, a different surface phase is observed above melting. Finally, our results also impact general liquid-phase issues like supramolecular self-aggregation and bulk–surface structure relations.« less

Effect of induced cohesion on stick-slip dynamics in weakly saturated, sheared granular fault gouge

DOE PAGES

Dorostkar, Omid; Guyer, Robert A.; Johnson, Paul Allan; ...

2018-02-28

We use three-dimensional discrete element calculations to study stick-slip dynamics in a weakly wet granular layer designed to simulate fault gouge. The granular gouge is constituted by 8000 spherical particles with a poly-disperse size distribution. At very low liquid content, liquids impose cohesive and viscous forces on particles. Our simulations show that by increasing the liquid content, friction increases and granular layer shows higher recurrence time between slip events. We also observe that slip events exhibit larger friction drop and layer compaction in wet system compared to dry. We demonstrate that a small volume of liquid induces cohesive forces betweenmore » wet particles that are responsible for an increase in coordination number leading to a more stable arrangement of particles. This stabilization is evidenced with two orders of magnitude lower particle kinetic energy in wet system during stick phase. Similar to previous experimental studies, we observe enhanced frictional strength for wet granular layers. In experiments, the physicochemical processes are believed to be the main reason for such behavior, we show however, that at low confining stresses the hydromechanical effects of induced cohesion are sufficient for observed behavior. Our simulations illuminate the role of particle interactions and demonstrate the conditions under which induced cohesion plays a significant role in fault zone processes, including slip initiation, weakening, and failure.« less

Effect of induced cohesion on stick-slip dynamics in weakly saturated, sheared granular fault gouge

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dorostkar, Omid; Guyer, Robert A.; Johnson, Paul Allan

We use three-dimensional discrete element calculations to study stick-slip dynamics in a weakly wet granular layer designed to simulate fault gouge. The granular gouge is constituted by 8000 spherical particles with a poly-disperse size distribution. At very low liquid content, liquids impose cohesive and viscous forces on particles. Our simulations show that by increasing the liquid content, friction increases and granular layer shows higher recurrence time between slip events. We also observe that slip events exhibit larger friction drop and layer compaction in wet system compared to dry. We demonstrate that a small volume of liquid induces cohesive forces betweenmore » wet particles that are responsible for an increase in coordination number leading to a more stable arrangement of particles. This stabilization is evidenced with two orders of magnitude lower particle kinetic energy in wet system during stick phase. Similar to previous experimental studies, we observe enhanced frictional strength for wet granular layers. In experiments, the physicochemical processes are believed to be the main reason for such behavior, we show however, that at low confining stresses the hydromechanical effects of induced cohesion are sufficient for observed behavior. Our simulations illuminate the role of particle interactions and demonstrate the conditions under which induced cohesion plays a significant role in fault zone processes, including slip initiation, weakening, and failure.« less

Surface structure evolution in a homologous series of ionic liquids

DOE PAGES

Haddad, Julia; Pontoni, Diego; Murphy, Bridget M.; ...

2018-01-22

Interfaces of room temperature ionic liquids (RTILs) are important for both applications and basic science and are therefore intensely studied. However, the evolution of their interface structure with the cation’s alkyl chain length n from Coulomb to van der Waals interaction domination has not yet been studied for even a single broad homologous RTIL series. We present in this paper such a study of the liquid–air interface for n = 2 to 22, using angstrom-resolution X-ray methods. For n < 6, a typical “simple liquid” monotonic surface-normal electron density profile ρ e more » ( z ) is obtained, like those of water and organic solvents. For n > 6, increasingly more pronounced nanoscale self-segregation of the molecules’ charged moieties and apolar chains yields surface layering with alternating regions of headgroups and chains. The layering decays into the bulk over a few, to a few tens, of nanometers. The layering periods and decay lengths, their linear n dependence, and slopes are discussed within two models, one with partial-chain interdigitation and the other with liquid-like chains. No surface-parallel long-range order is found within the surface layer. For n = 22, a different surface phase is observed above melting. Finally, our results also impact general liquid-phase issues like supramolecular self-aggregation and bulk–surface structure relations.« less

Analysis of liquid-phase chemical detection using guided shear horizontal-surface acoustic wave sensors.

PubMed

Li, Zhonghui; Jones, Yolanda; Hossenlopp, Jeanne; Cernosek, Richard; Josse, Fabien

2005-07-15

Direct chemical sensing in liquid environments using polymer-guided shear horizontal surface acoustic wave sensor platforms on 36 degrees rotated Y-cut LiTaO3 is investigated. Design considerations for optimizing these devices for liquid-phase detection are systematically explored. Two different sensor geometries are experimentally and theoretically analyzed. Dual delay line devices are used with a reference line coated with poly (methyl methacrylate) (PMMA) and a sensing line coated with a chemically sensitive polymer, which acts as both a guiding layer and a sensing layer or with a PMMA waveguide and a chemically sensitive polymer. Results show the three-layer model provides higher sensitivity than the four-layer model. Contributions from mass loading and coating viscoelasticity changes to the sensor response are evaluated, taking into account the added mass, swelling, and plasticization. Chemically sensitive polymers are investigated in the detection of low concentrations (1-60 ppm) of toluene, ethylbenzene, and xylenes in water. A low-ppb level detection limit is estimated from the present experimental measurements. Sensor properties are investigated by varying the sensor geometries, coating thickness combinations, coating properties, and curing temperature for operation in liquid environments. Partition coefficients for polymer-aqueous analyte pairs are used to explain the observed trend in sensitivity for the polymers PMMA, poly(isobutylene), poly(epichlorohydrin), and poly(ethyl acrylate) used in this work.

On the Method of Efficient Ice Cold Energy Storage Using a Heat Transfer of Direct Contact Phase Change and a Natural Circulation of a Working Medium in an Enclosure

NASA Astrophysics Data System (ADS)

Utaka, Yoshio; Saito, Akio; Nakata, Naoki

The objectives of this report are to propose a new method of the high performance cold energy storage using ice as a phase change material and to clarify the heat transfer characteristics of the apparatus of ice cold energy storage based on the proposed principle. A working medium vapor layer a water layer and a working medium liquid layer stratified in this order from the top were kept in an enclosure composed of a condenser, an evaporator and a condensate receiver-and-return tube. The direct contact heat transfers between water or ice and a working medium in an enclosure were applied for realizing the high performance cold energy storage and release. In the storage and release processes, water changes the phase between the liquid and the solid, and the working medium cnanges between the vapor and the liquid with a natural circulation. Experimental apparatus was manufactured and R12 and R114 were selected as working media in the thermal energy storage enclosure. It was confirmed by the measurements that the efficient formation and melting of ice were achieved. Then, th e heat transfer characteristics were clarified for the effects of the initial water height, the initial height of woking medium liquid layer and the inlet coolant temperature.

Cohesion-Induced Stabilization in Stick-Slip Dynamics of Weakly Wet, Sheared Granular Fault Gouge

NASA Astrophysics Data System (ADS)

Dorostkar, Omid; Guyer, Robert A.; Johnson, Paul A.; Marone, Chris; Carmeliet, Jan

2018-03-01

We use three-dimensional discrete element calculations to study stick-slip dynamics in a weakly wet granular layer designed to simulate fault gouge. The granular gouge is constituted by 8,000 spherical particles with a polydisperse size distribution. At very low liquid content, liquids impose cohesive and viscous forces on particles. Our simulations show that by increasing the liquid content, friction increases and granular layer shows higher recurrence time between slip events. We also observe that slip events exhibit larger friction drop and layer compaction in wet system compared to dry. We demonstrate that a small volume of liquid induces cohesive forces between wet particles that are responsible for an increase in coordination number leading to a more stable arrangement of particles. This stabilization is evidenced with 2 orders of magnitude lower particle kinetic energy in wet system during stick phase. Similar to previous experimental studies, we observe enhanced frictional strength for wet granular layers. In experiments, the physicochemical processes are believed to be the main reason for such behavior; we show, however, that at low confining stresses, the hydromechanical effects of induced cohesion are sufficient for observed behavior. Our simulations illuminate the role of particle interactions and demonstrate the conditions under which induced cohesion plays a significant role in fault zone processes, including slip initiation, weakening, and failure.

Superabsorbent Multilayer Fabric

NASA Technical Reports Server (NTRS)

Coreale, J. V.; Dawn, F. S.

1982-01-01

Material contains gel-forming polymer and copolymer that absorb from 70 to 200 times their weight of liquid. Superabsorbent Polymer and Copolymer form gels to bind and retain liquid in multiply fabric. Until reaction between liquid and absorbent masses forms gel, backing layer retains liquids within fabric; also allows material to "breathe." Possible applications include baby diapers, female hygiene napkins, and hospital bedpads. Might also have uses in improvement of dry soil.

Harvesting contaminants from liquid

DOEpatents

Simpson, John T.; Hunter, Scott R.

2016-05-31

Disclosed are examples of apparatuses for evaporative purification of a contaminated liquid. In each example, there is a vessel for storing the contaminated fluid. The vessel includes a surface coated with a layer of superhydrophobic material and the surface is at least partially in contact with the contaminated liquid. The contaminants do not adhere to the surface as the purified liquid evaporates, thus allowing the contaminants to be harvested.

HEAT TRANSFER TO LIQUID METALS FLOWING THROUGH A PIPELINE (in Russian)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Borishanskii, V.M.; Zablotskaya, T.V.; Ivashchenko, N.I.

1963-03-01

A scheme involving the superposition of three layers of heat flow onto the high thermal-conductivity liquid flowing with a Prandtl number Pr << 1 was previously proposed (Atomnaya Energ. 11, 426(1961) No. 5; also Second Conference on Theoretical and Applied Magnetohydrodynamics, Riga, 1962). The analytical determination of these thermal layer boundaries was based on the premise that the dimensionless temperature and velocity fields coincide in the region where the dynamic and thermal cores are turbulent; the boundary of the adherent layer in which molecular transfer takes place was determined by a newly derived formula. Results of the calculations of twomore » variants of the superimposition of thermal and dynamic layers were plotted and compared with each other. For an experimental study, the heat transfer to liquid Na flowing through a 40-mmdiam. vertical Cu pipe was determined. The results agreed well with the values obtained by the three-layer calculations. Determination of the O content of Na showed that the heat transfer is dependent on the average O content and also on the flow rate of the Na stream. As the O content that was encountered exceeded the solubility limit, a portion of the oxides was probably present in the suspended state. (TTT)« less

Effect of Group-III precursors on unintentional gallium incorporation during epitaxial growth of InAlN layers by metalorganic chemical vapor deposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, Jeomoh, E-mail: jkim610@gatech.edu; Ji, Mi-Hee; Detchprohm, Theeradetch

2015-09-28

Unintentional incorporation of gallium (Ga) in InAlN layers grown with different molar flow rates of Group-III precursors by metalorganic chemical vapor deposition has been experimentally investigated. The Ga mole fraction in the InAl(Ga)N layer was increased significantly with the trimethylindium (TMIn) flow rate, while the trimethylaluminum flow rate controls the Al mole fraction. The evaporation of metallic Ga from the liquid phase eutectic system between the pyrolized In from injected TMIn and pre-deposited metallic Ga was responsible for the Ga auto-incorporation into the InAl(Ga)N layer. The theoretical calculation on the equilibrium vapor pressure of liquid phase Ga and the effectivemore » partial pressure of Group-III precursors based on growth parameters used in this study confirms the influence of Group-III precursors on Ga auto-incorporation. More Ga atoms can be evaporated from the liquid phase Ga on the surrounding surfaces in the growth chamber and then significant Ga auto-incorporation can occur due to the high equilibrium vapor pressure of Ga comparable to effective partial pressure of input Group-III precursors during the growth of InAl(Ga)N layer.« less

Liquid eutectic GaIn as an alternative electrode for PTB7:PCBM organic solar cells

NASA Astrophysics Data System (ADS)

Thanh Hau Pham, Viet; Kieu Trinh, Thanh; Tam Nguyen Truong, Nguyen; Park, Chinho

2017-04-01

Conventional vacuum deposition process of aluminum (Al) is costly, time-consuming and difficult to apply to the large-scale production of organic photovoltaic devices (OPV). This paper reports a vacuum-free fabrication process of poly[[4,8-bis(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b‧]dithiophene-2,6-diyl][3-fluoro-2-[(2-ethylhexyl)carbonyl]thienophenediyl]:[6,6]-phenyl C71 butyric acid methyl ester (PTB7:PCBM) bulk heterojunction organic solar cell with liquid eutectic gallium-indium (EGaIn) electrode as an alternative to the common Al electrode. The insertion of a thin poly(ethylene oxide) (PEO) layer after depositing organic photoactive layer could help prevent the diffusion of liquid EGaIn into the active layer and allow the deposition of the EGaIn electrode. The PEO interfacial layer was formed by spin-coating from a mixed solvent of alcohol and water. Among different alcohol+water (methanol, ethanol, ethylene glycol, n-propanol, isopropanol, and isobutanol) mixed solvent tested, the n-propanol+water mixed solvent showed the greatest enhancement to the performance of OPVs. The improved device performance was attributed to the reactivity of mixed solvent n-propanol+water toward the surface of PTB7:PCBM active layer, which could help optimize surface morphology.

Simultaneous detection of multiple biomarkers by means of SERS on polymer nanopillar gold arrays

NASA Astrophysics Data System (ADS)

Morasso, Carlo; Picciolini, Silvia; Mehn, Dora; Pellacani, Paola; Frangolho, Ana; Marchesini, Gerardo; Vanna, Renzo; Gualerzi, Alice; Bedoni, Marzia; Marabelli, Franco; Gramatica, Furio

2016-03-01

The detection of biomarkers by means of Surface Enhanced Raman Spectroscopy (SERS) is foreseen to became a very important tool in the clinical practice because of its excellent sensitivity and potential for the simultaneous detection of multiple biomarkers. In the present paper we describe how it was possible to build a sensor for the detection of genetic biomarkers involved in acute myeloid leukemia. The assay is based on the use of a specifically designed SERS substrate made of a 2D crystal structure of polymeric pillars embedded in a gold layer. This substrate is characterized by good enhancing properties coupled with an excellent homogeneity. The SERS substrate was conjugated with DNA probes complementary to a target sequence and used in a sandwich assay with gold nanoparticles labeled with a second DNA probe and a Raman reporter. The so developed assay allowed the detection of a leukemia biomarker (WT1 gene) and an housekeeping gene with low picomolar sensitivity. At last, we optimized the assay in order to tackle one of the main limitations of SERS based assay: the loss of signal that is observed when the Raman spectra are collected in liquid. Combining a preferential functionalization on the polymeric pillars with a different height of the polymer pillars from the gold layer the assay demonstrated its effectiveness even when measured in buffer.

Lithium-ion batteries having conformal solid electrolyte layers

DOEpatents

Kim, Gi-Heon; Jung, Yoon Seok

2014-05-27

Hybrid solid-liquid electrolyte lithium-ion battery devices are disclosed. Certain devices comprise anodes and cathodes conformally coated with an electron insulating and lithium ion conductive solid electrolyte layer.

NASA Tech Briefs, February 2004

NASA Technical Reports Server (NTRS)

2004-01-01

Topics include: Simulation Testing of Embedded Flight Software; Improved Indentation Test for Measuring Nonlinear Elasticity; Ultraviolet-Absorption Spectroscopic Biofilm Monitor; Electronic Tongue for Quantitation of Contaminants in Water; Radar for Measuring Soil Moisture Under Vegetation; Modular Wireless Data-Acquisition and Control System; Microwave System for Detecting Ice on Aircraft; Routing Algorithm Exploits Spatial Relations; Two-Finger EKG Method of Detecting Evasive Responses; Updated System-Availability and Resource-Allocation Program; Routines for Computing Pressure Drops in Venturis; Software for Fault-Tolerant Matrix Multiplication; Reproducible Growth of High-Quality Cubic-SiC Layers; Nonlinear Thermoelastic Model for SMAs and SMA Hybrid Composites; Liquid-Crystal Thermosets, a New Generation of High-Performance Liquid-Crystal Polymers; Formulations for Stronger Solid Oxide Fuel-Cell Electrolytes; Simulation of Hazards and Poses for a Rocker-Bogie Rover; Autonomous Formation Flight; Expandable Purge Chambers Would Protect Cryogenic Fittings; Wavy-Planform Helicopter Blades Make Less Noise; Miniature Robotic Spacecraft for Inspecting Other Spacecraft; Miniature Ring-Shaped Peristaltic Pump; Compact Plasma Accelerator; Improved Electrohydraulic Linear Actuators; A Software Architecture for Semiautonomous Robot Control; Fabrication of Channels for Nanobiotechnological Devices; Improved Thin, Flexible Heat Pipes; Miniature Radioisotope Thermoelectric Power Cubes; Permanent Sequestration of Emitted Gases in the Form of Clathrate Hydrates; Electrochemical, H2O2-Boosted Catalytic Oxidation System; Electrokinetic In Situ Treatment of Metal-Contaminated Soil; Pumping Liquid Oxygen by Use of Pulsed Magnetic Fields; Magnetocaloric Pumping of Liquid Oxygen; Tailoring Ion-Thruster Grid Apertures for Greater Efficiency; and Lidar for Guidance of a Spacecraft or Exploratory Robot.

A generalized theory of chromatography and multistep liquid extraction

NASA Astrophysics Data System (ADS)

Chizhkov, V. P.; Boitsov, V. N.

2017-03-01

A generalized theory of chromatography and multistep liquid extraction is developed. The principles of highly efficient processes for fine preparative separation of binary mixture components on a fixed sorbent layer are discussed.

Impact of droplet on superheated surfaces

NASA Astrophysics Data System (ADS)

Lohse, Detlef; Staat, Hendrik J. J.; Tran, Tuan; Prosperetti, Andrea; Sun, Chao

2012-11-01

At impact of a liquid droplet on a smooth surface heated way above the liquid's boiling point, the droplet spreads without any surface contact, floating on its own (Leidenfrost-type) vapor layer, and then bounces back. We show that the dimensionless maximum spreading factor Γ, defined by the ratio of the maximal spreading diameter and the droplet diameter, shows a universal scaling Γ ~ Weγ with the Weber number We - regardless of surface temperature and of liquid properties - which is much steeper than that for the impact on non-heated (hydrophilic or hydrophobic) surfaces, for which γ = 1 / 4 . Based on the idea that the vapor shooting out of the gap between the droplet and the superheated surface drags the liquid outwards, we derive scaling laws for the spreading factor Γ, the vapor layer thickness, and the vapor flow velocity.

Apparatus for detecting leakage of liquid sodium

DOEpatents

Himeno, Yoshiaki

1978-01-01

An apparatus for detecting the leakage of liquid sodium includes a cable-like sensor adapted to be secured to a wall of piping or other equipment having sodium on the opposite side of the wall, and the sensor includes a core wire electrically connected to the wall through a leak current detector and a power source. An accidental leakage of the liquid sodium causes the corrosion of a metallic layer and an insulative layer of the sensor by products resulted from a reaction of sodium with water or oxygen in the atmospheric air so as to decrease the resistance between the core wire and the wall. Thus, the leakage is detected as an increase in the leaking electrical current. The apparatus is especially adapted for use in detecting the leakage of liquid sodium from sodium-conveying pipes or equipment in a fast breeder reactor.

Influence of temperature and molecular structure on ionic liquid solvation layers.

PubMed

Wakeham, Deborah; Hayes, Robert; Warr, Gregory G; Atkin, Rob

2009-04-30

Atomic force microscopy (AFM) force profiling is used to investigate the structure of adsorbed and solvation layers formed on a mica surface by various room temperature ionic liquids (ILs) ethylammonium nitrate (EAN), ethanolammonium nitrate (EtAN), ethylammonium formate (EAF), propylammonium formate (PAF), ethylmethylammonium formate (EMAF), and dimethylethylammonium formate (DMEAF). At least seven layers are observed for EAN at 14 degrees C (melting point 13 degrees C), decreasing as the temperature is increased to 30 degrees C due to thermal energy disrupting solvophobic forces that lead to segregation of cation alkyl tails from the charged ammonium and nitrate moieties. The number and properties of the solvation layers can also be controlled by introducing an alcohol moiety to the cation's alkyl tail (EtAN), or by replacing the nitrate anion with formate (EAF and PAF), even leading to the detection of distinct cation and anion sublayers. Substitution of primary by secondary or tertiary ammonium cations reduces the number of solvation layers formed, and also weakens the cation layer adsorbed onto mica. The observed solvation and adsorbed layer structures are discussed in terms of the intermolecular cohesive forces within the ILs.

Separated rupture and retraction of a bi-layer free film

NASA Astrophysics Data System (ADS)

Stewart, Peter; Feng, Jie; Griffiths, Ian

2017-11-01

We investigate the dynamics of a rising air bubble in an aqueous phase coated with a layer of oil. Recent experiments have shown that bubble rupture at the compound air/oil/aqueous interface can effectively disperse submicrometre oil droplets into the aqueous phase, suggesting a possible mechanism for clean-up of oil spillages on the surface of the ocean. Using a theoretical model we consider the stability of the long liquid free film formed as the bubble reaches the free surface, composed of two immiscible layers of differing viscosities, where each layer experiences a van der Waals force between its interfaces. For an excess of surfactant on one gas-liquid interface we show that the instability manifests as distinct rupture events, with the oil layer rupturing first and retracting over the in-tact water layer beneath, consistent with the experimental observations. We use our model to examine the dynamics of oil retraction, showing that it follows a power-law for short times, and examine the influence of retraction on the stability of the water layer.

Formation of a Crack-Free, Hybrid Skin Layer with Tunable Surface Topography and Improved Gas Permeation Selectivity on Elastomers Using Gel–Liquid Infiltration Polymerization

DOE PAGES

Wang, Mengyuan; Gorham, Justin M.; Killgore, Jason P.; ...

2017-07-31

Surface modifications of elastomers and gels are crucial for emerging applications such as soft robotics and flexible electronics, in large part because they provide a platform to control wettability, adhesion, and permeability. Current surface modification methods via ultraviolet-ozone (UVO) and/or O2 plasma, atomic layer deposition (ALD), plasmas deposition, and chemical treatment impart a dense polymer or inorganic layer on the surface that is brittle and easy to fracture at low strain levels. This paper presents a new method, based on gel–liquid infiltration polymerization, to form hybrid skin layers atop elastomers. The method is unique in that it allows for controlmore » of the skin layer topography, with tunable feature sizes and aspect ratios as high as 1.8 without fracture. Unlike previous techniques, the skin layer formed here dramatically improves the barrier properties of the elastomer, while preserving skin layer flexibility. Furthermore, the method is versatile and likely applicable to most interfacial polymerization systems and network polymers on flat and patterned surfaces.« less

Formation of a Crack-Free, Hybrid Skin Layer with Tunable Surface Topography and Improved Gas Permeation Selectivity on Elastomers Using Gel–Liquid Infiltration Polymerization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Mengyuan; Gorham, Justin M.; Killgore, Jason P.

Surface modifications of elastomers and gels are crucial for emerging applications such as soft robotics and flexible electronics, in large part because they provide a platform to control wettability, adhesion, and permeability. Current surface modification methods via ultraviolet-ozone (UVO) and/or O2 plasma, atomic layer deposition (ALD), plasmas deposition, and chemical treatment impart a dense polymer or inorganic layer on the surface that is brittle and easy to fracture at low strain levels. This paper presents a new method, based on gel–liquid infiltration polymerization, to form hybrid skin layers atop elastomers. The method is unique in that it allows for controlmore » of the skin layer topography, with tunable feature sizes and aspect ratios as high as 1.8 without fracture. Unlike previous techniques, the skin layer formed here dramatically improves the barrier properties of the elastomer, while preserving skin layer flexibility. Furthermore, the method is versatile and likely applicable to most interfacial polymerization systems and network polymers on flat and patterned surfaces.« less

Matrix formalism of electromagnetic wave propagation through multiple layers in the near-field region: application to the flat panel display.

PubMed

Lee, C Y; Lee, D E; Hong, Y K; Shim, J H; Jeong, C K; Joo, J; Zang, D S; Shim, M G; Lee, J J; Cha, J K; Yang, H G

2003-04-01

We have developed an electromagnetic (EM) wave propagation theory through a single layer and multiple layers in the near-field and far-field regions, and have constructed a matrix formalism in terms of the boundary conditions of the EM waves. From the shielding efficiency (SE) against EM radiation in the near-field region calculated by using the matrix formalism, we propose that the effect of multiple layers yields enhanced shielding capability compared to a single layer with the same total thickness in conducting layers as the multiple layers. We compare the intensities of an EM wave propagating through glass coated with conducting indium tin oxide (ITO) on one side and on both sides, applying it to the electromagnetic interference (EMI) shielding filter in a flat panel display such as a plasma display panel (PDP). From the measured intensities of EMI noise generated by a PDP loaded with ITO coated glass samples, the two-side coated glass shows a lower intensity of EMI noise compared to the one-side coated glass. The result confirms the enhancement of the SE due to the effect of multiple layers, as expected in the matrix formalism of EM wave propagation in the near-field region. In the far-field region, the two-side coated glass with ITO in multiple layers has a higher SE than the one-side coated glass with ITO, when the total thickness of ITO in both cases is the same.

Flexible, liquid core light guide with focusing and light shaping attachments

DOEpatents

Wojcik, Randolph Frank; Majewski, Stanislaw; Zorn, Carl John; Kross, Brian

1999-01-01

A liquid light guide system for ultraviolet light is disclosed that has a light shaping arrangement for the emitted light, a stable liquid core and sheath and reliable and effective end closures. The end closures include a metal crimping arrangement that utilizes two layers of deformable materials to prevent cracking of endplugs.

Slippery self-lubricating polymer surfaces

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aizenberg, Joanna; Aizenberg, Michael; Cui, Jiaxi

The present disclosure describes a strategy to create self-healing, slippery self-lubricating polymers. Lubricating liquids with affinities to polymers can be utilized to get absorbed within the polymer and form a lubricant layer (of the lubricating liquid) on the polymer. The lubricant layer can repel a wide range of materials, including simple and complex fluids (water, hydrocarbons, crude oil and bodily fluids), restore liquid-repellency after physical damage, and resist ice, microorganisms and insects adhesion. Some exemplary applications where self-lubricating polymers will be useful include energy-efficient, friction-reduction fluid handling and transportation, medical devices, anti-icing, optical sensing, and as self-cleaning, and anti-fouling materialsmore » operating in extreme environments.« less

Characterization of the dynamics of surface stabilized ferroelectric liquid crystal under electric field by full optical snapshot matrix Mueller polarimeter

NASA Astrophysics Data System (ADS)

Silva, Vinicius N. H.; Babilotte, Philippe; Rivet, Sylvain; Dubreuil, Mathieu; Le Jeune, Bernard; Dupont, Laurent

2012-12-01

We investigated the layer dynamics of a conventional surface-stabilized ferroelectric liquid crystal (SSFLC) using a full-optical snapshot Mueller matrix polarimeter (SMMP) based on wavelength polarization coding. Time-resolved polarimetric measurements were performed with different SSFLC samples, and a strong correlation between the polarimetric parameters and the SSFLC under electric field at different exposure times was found. It has been shown that the SMMP polarimeter is able to determine the evolution of the trajectory of the liquid crystal director between the two addressed states, the reversible motion of the smectic layer while switching, as well as the irreversible transition from chevron to bookshelf texture.

One-step method for the production of nanofluids

DOEpatents

Kostic, Milivoje [Chicago, IL; Golubovic, Mihajlo [Chicago, IL; Hull, John R [Downers Grove, IL; Choi, Stephen U. S. [Napersville, IL

2010-05-18

A one step method and system for producing nanofluids by a particle-source evaporation and deposition of the evaporant into a base fluid. The base fluid such (i.e. ethylene glycol) is placed in a rotating cylindrical drum having an adjustable heater-boat-evaporator and heat exchanger-cooler apparatus. As the drum rotates, a thin liquid layer is formed on the inside surface of the drum. A heater-boat-evaporator having an evaporant material (particle-source) placed within its boat evaporator is adjustably positioned near a portion of the rotating thin liquid layer, the evaporant material being heated thereby evaporating a portion of the evaporant material, the evaporated material absorbed by the liquid film to form nanofluid.

A novel boundary layer sensor utilizing domain switching in ferroelectric liquid crystals

NASA Technical Reports Server (NTRS)

Parmar, D. S.

1991-01-01

This paper describes the design and the principles of operation of a novel sensor for the optical detection of a shear stress field induced by air or gas flow on a rigid surface. The detection relies on the effects of shear-induced optical switching in ferroelectric liquid crystals. It is shown that the method overcomes many of the limitations of similar measuring techniques including those using cholesteric liquid crystals. The present method offers a preferred alternative for flow visualization and skin friction measurements in wind-tunnel experiments on laminar boundary layer transition investigations. A theoretical model for the optical response to shear stress is presented together with a schematic diagram of the experimental setup.

Variable convergence liquid layer implosions on the National Ignition Facility

DOE PAGES

Zylstra, A. B.; Yi, S. A.; Haines, B. M.; ...

2018-03-19

Liquid layer implosions using the “wetted foam” technique, where the liquid fuel is wicked into a supporting foam, have been recently conducted on the National Ignition Facility for the first time [Olson et al., Phys. Rev. Lett. 117, 245001 (2016)]. In this paper, we report on a series of wetted foam implosions where the convergence ratio was varied between 12 and 20. Reduced nuclear performance is observed as convergence ratio increases. 2-D radiation-hydrodynamics simulations accurately capture the performance at convergence ratios (CR) ~ 12, but we observe a significant discrepancy at CR ~ 20. Finally, this may be due tomore » suppressed hot-spot formation or an anomalous energy loss mechanism.« less

Variable convergence liquid layer implosions on the National Ignition Facility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zylstra, A. B.; Yi, S. A.; Haines, B. M.

Liquid layer implosions using the “wetted foam” technique, where the liquid fuel is wicked into a supporting foam, have been recently conducted on the National Ignition Facility for the first time [Olson et al., Phys. Rev. Lett. 117, 245001 (2016)]. In this paper, we report on a series of wetted foam implosions where the convergence ratio was varied between 12 and 20. Reduced nuclear performance is observed as convergence ratio increases. 2-D radiation-hydrodynamics simulations accurately capture the performance at convergence ratios (CR) ~ 12, but we observe a significant discrepancy at CR ~ 20. Finally, this may be due tomore » suppressed hot-spot formation or an anomalous energy loss mechanism.« less

Diffuse-charge dynamics of ionic liquids in electrochemical systems.

PubMed

Zhao, Hui

2011-11-01

We employ a continuum theory of solvent-free ionic liquids accounting for both short-range electrostatic correlations and steric effects (finite ion size) [Bazant et al., Phys. Rev. Lett. 106, 046102 (2011)] to study the response of a model microelectrochemical cell to a step voltage. The model problem consists of a 1-1 symmetric ionic liquid between two parallel blocking electrodes, neglecting any transverse transport phenomena. Matched asymptotic expansions in the limit of thin double layers are applied to analyze the resulting one-dimensional equations and study the overall charge-time relation in the weakly nonlinear regime. One important conclusion is that our simple scaling analysis suggests that the length scale √(λ*(D)l*(c)) accurately characterizes the double-layer structure of ionic liquids with strong electrostatic correlations where l*(c) is the electrostatic correlation length (in contrast, the Debye screening length λ*(D) is the primary double-layer length for electrolytes) and the response time of λ(D)(*3/2)L*/(D*l(c)(1/2)) (not λ*(D)L*/D* that is the primary charging time of electrolytes) is the correct charging time scale of ionic liquids with strong electrostatic correlations where D* is the diffusivity and L* is the separation length of the cell. With these two new scales, data of both electric potential versus distance from the electrode and the total diffuse charge versus time collapse onto each individual master curve in the presence of strong electrostatic correlations. In addition, the dependance of the total diffuse charge on steric effects, short-range correlations, and driving voltages is thoroughly examined. The results from the asymptotic analysis are compared favorably with those from full numerical simulations. Finally, the absorption of excess salt by the double layer creates a depletion region outside the double layer. Such salt depletion may bring a correction to the leading order terms and break down the weakly nonlinear analysis. A criterion which justifies the weakly nonlinear analysis is verified with numerical simulations.

Confinement-Driven Phase Separation of Quantum Liquid Mixtures

NASA Astrophysics Data System (ADS)

Prisk, T. R.; Pantalei, C.; Kaiser, H.; Sokol, P. E.

2012-08-01

We report small-angle neutron scattering studies of liquid helium mixtures confined in Mobil Crystalline Material-41 (MCM-41), a porous silica glass with narrow cylindrical nanopores (d=3.4nm). MCM-41 is an ideal model adsorbent for fundamental studies of gas sorption in porous media because its monodisperse pores are arranged in a 2D triangular lattice. The small-angle scattering consists of a series of diffraction peaks whose intensities are determined by how the imbibed liquid fills the pores. Pure He4 adsorbed in the pores show classic, layer-by-layer film growth as a function of pore filling, leaving the long range symmetry of the system intact. In contrast, the adsorption of He3-He4 mixtures produces a structure incommensurate with the pore lattice. Neither capillary condensation nor preferential adsorption of one helium isotope to the pore walls can provide the symmetry-breaking mechanism. The scattering is consistent with the formation of randomly distributed liquid-liquid microdomains ˜2.3nm in size, providing evidence that confinement in a nanometer scale capillary can drive local phase separation in quantum liquid mixtures.

Effect of Rheological Properties on Liquid Curtain Coating

NASA Astrophysics Data System (ADS)

Mohammad Karim, Alireza; Suszynski, Wieslaw; Griffith, William; Pujari, Saswati; Carvalho, Marcio; Francis, Lorraine; Dow Chemical Company Collaboration; PUC-Rio Collaboration

2017-11-01

Curtain coating is one of the preferred methods for high-speed precision application of single-layer and multi-layer coatings in technology. However, uniform coatings are only obtained in a certain range of operating parameters, called coating window. The two main physical mechanisms that limit successful curtain coating are liquid curtain breakup and air entrainment. The rheological properties of the liquid play an important role on these mechanisms, but the fundamental understanding of these relations is still not complete. The effect of rate-dependent shear and extensional viscosities on the stability of viscoelastic and shear thinning liquid curtains were explored by high-speed visualization. Aqueous solutions of polyethylene oxide (PEO) and polyethylene glycol (PEG) were used as viscoelastic liquids. Xanthan Gum in water and glycerol solutions with a range of compositions were used as shear thinning liquids. The critical condition was determined by examining flow rate below which curtain broke. In this work, we also analyze relative importance of rate-dependent shear and extensional viscosity on both curtain breakup and air entrainment. We would like to acknowledge the financial support from the Dow Chemical Company.

Liquid Water in the Extremely Shallow Martian Subsurface

NASA Technical Reports Server (NTRS)

Pavlov, A.; Shivak, J. N.

2012-01-01

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

Validation of a Multiresidue Analysis Method for 379 Pesticides in Human Serum Using Liquid Chromatography-Tandem Mass Spectrometry.

PubMed

Shin, Yongho; Lee, Jonghwa; Lee, Jiho; Lee, Junghak; Kim, Eunhye; Liu, Kwang-Hyeon; Lee, Hye Suk; Kim, Jeong-Han

2018-04-04

A screening method for simultaneous analysis of 379 pesticides in human serum was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Electrospray ionization with positive/negative switching mode of LC-MS/MS was adopted, and scheduled multiple reaction monitoring for each target compound was established. The limit of quantitation was 10 ng/mL for 94.5% of the total pesticides, and the correlation coefficients of calibration were ≥0.990 for 93.9% of the pesticides. For the sample preparation, scaled-down QuEChERS were used. Serum (100 μL) was extracted with acetonitrile (400 μL), partitioned with magnesium sulfate (40 mg) and sodium chloride (10 mg), and the upper layer was used for analysis without further cleanup steps. For the accuracy and precision tests, most of the pesticides showed excellent results in intra- and interday conditions. In the recovery tests at 10, 50, and 250 ng/mL, 85.8-91.8% of all target compounds satisfied the recovery range of 70-120% (relative standard deviation ≤20%).

Chemical-Specific Representation of Air-Soil Exchange and Soil Penetration in Regional Multimedia Models

DOE Office of Scientific and Technical Information (OSTI.GOV)

McKone, T.E.; Bennett, D.H.

2002-08-01

In multimedia mass-balance models, the soil compartment is an important sink as well as a conduit for transfers to vegetation and shallow groundwater. Here a novel approach for constructing soil transport algorithms for multimedia fate models is developed and evaluated. The resulting algorithms account for diffusion in gas and liquid components; advection in gas, liquid, or solid phases; and multiple transformation processes. They also provide an explicit quantification of the characteristic soil penetration depth. We construct a compartment model using three and four soil layers to replicate with high reliability the flux and mass distribution obtained from the exact analyticalmore » solution describing the transient dispersion, advection, and transformation of chemicals in soil with fixed properties and boundary conditions. Unlike the analytical solution, which requires fixed boundary conditions, the soil compartment algorithms can be dynamically linked to other compartments (air, vegetation, ground water, surface water) in multimedia fate models. We demonstrate and evaluate the performance of the algorithms in a model with applications to benzene, benzo(a)pyrene, MTBE, TCDD, and tritium.« less

Influence of micro-oxidation on joints of C/C composites and GH3044 for large-size aerospace parts

NASA Astrophysics Data System (ADS)

Shi, Xiaohong; Jin, Xiuxiu; Yan, Ningning; Yang, Li

2017-11-01

To improve the bonding strength of carbon/carbon (C/C) composites and GH3044 nickel-based superalloy, the bonding interlayer with Ti/Ni/Cu/Ni multiple foils were prepared by a two-step technique involving micro-oxidation and partial transient liquid phase (PTLP) process. Interface characteristics and mechanical behavior of joints were investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), laser scanning confocal microscope (LSCM) and energy X-ray dispersive spectrometer (EDS). Results show that a porous layer on C/C composites is formed by micro-oxidation for more than 2 min at 1073 K in air, which provides a diffusion path for liquid phase to infiltrate into C/C substrate and generate a wedge interlocking interface. After micro-oxidation for 4 min, the shear strength of joints reaches 32.09 ± 1.98 MPa what is 36.73% higher than that of joints without micro-oxidation (23.47 ± 1.15 MPa). The increase of shear strength remarkably depends on physical interlocking and chemical bonding at porous interface.

In situ SEM Study of Lithium Intercalation in individual V 2O 5 Nanowires

DOE PAGES

Strelcov, Evgheni; Cothren, Joshua E.; Leonard, Donovan N.; ...

2015-01-08

Progress in rational engineering of Li-ion batteries requires better understanding of the electrochemical processes and accompanying transformations in the electrode materials on multiple length scales. In spite of recent progress in utilizing transmission electron microscopy (TEM) to analyze these materials, in situ scanning electron microscopy (SEM) was mostly overlooked as a powerful tool that allows probing these phenomena on the nano and mesoscale. In this paper, we report on in situ SEM study of lithiation in a V 2O 5-based single-nanobelt battery with ionic liquid electrolyte. Coupled with cyclic voltammetry measurements, in situ SEM revealed the peculiarities of subsurface intercalation,more » formation of solid-electrolyte interface (SEI) and electromigration of liquid. We observed that single-crystalline vanadia nanobelts do not undergo large-scale amorphization or fracture during electrochemical cycling, but rather transform topochemically with only a slight shape distortion. Lastly, the SEI layer seems to have significant influence on the lithium ion diffusion and overall capacity of the single-nanobelt battery.« less

Liquid-like thermal conduction in intercalated layered crystalline solids

DOE PAGES

Li, B.; Wang, H.; Kawakita, Y.; ...

2018-01-15

As a generic property, all substances transfer heat through microscopic collisions of constituent particles. A solid conducts heat through both transverse and longitudinal acoustic phonons, but a liquid employs only longitudinal vibrations. As a result, a solid is usually thermally more conductive than a liquid. In canonical viewpoints, such a difference also serves as the dynamic signature distinguishing a solid from a liquid. Here in this work, we report liquid-like thermal conduction observed in the crystalline AgCrSe 2. The transverse acoustic phonons are completely suppressed by the ultrafast dynamic disorder while the longitudinal acoustic phonons are strongly scattered but survive,more » and are thus responsible for the intrinsically ultralow thermal conductivity. This scenario is applicable to a wide variety of layered compounds with heavy intercalants in the van der Waals gaps, manifesting a broad implication on suppressing thermal conduction. Finally, these microscopic insights might reshape the fundamental understanding on thermal transport properties of matter and open up a general opportunity to optimize performances of thermoelectrics.« less

Breaking through the glass ceiling: The correlation between the self-diffusivity in and krypton permeation through deeply supercooled liquid nanoscale methanol films

NASA Astrophysics Data System (ADS)

Smith, R. Scott; Matthiesen, Jesper; Kay, Bruce D.

2010-03-01

Molecular beam techniques, temperature-programmed desorption (TPD), and reflection absorption infrared spectroscopy (RAIRS) are used to explore the relationship between krypton permeation through and the self-diffusivity of supercooled liquid methanol at temperatures (100-115 K) near the glass transition temperature, Tg (103 K). Layered films, consisting of CH3OH and CD3OH, are deposited on top of a monolayer of Kr on a graphene covered Pt(111) substrate at 25 K. Concurrent Kr TPD and RAIRS spectra are acquired during the heating of the composite film to temperatures above Tg. The CO vibrational stretch is sensitive to the local molecular environment and is used to determine the supercooled liquid diffusivity from the intermixing of the isotopic layers. We find that the Kr permeation and the diffusivity of the supercooled liquid are directly and quantitatively correlated. These results validate the rare-gas permeation technique as a tool for probing the diffusivity of supercooled liquids.

Breaking through the glass ceiling: the correlation between the self-diffusivity in and krypton permeation through deeply supercooled liquid nanoscale methanol films.

PubMed

Smith, R Scott; Matthiesen, Jesper; Kay, Bruce D

2010-03-28

Molecular beam techniques, temperature-programmed desorption (TPD), and reflection absorption infrared spectroscopy (RAIRS) are used to explore the relationship between krypton permeation through and the self-diffusivity of supercooled liquid methanol at temperatures (100-115 K) near the glass transition temperature, T(g) (103 K). Layered films, consisting of CH(3)OH and CD(3)OH, are deposited on top of a monolayer of Kr on a graphene covered Pt(111) substrate at 25 K. Concurrent Kr TPD and RAIRS spectra are acquired during the heating of the composite film to temperatures above T(g). The CO vibrational stretch is sensitive to the local molecular environment and is used to determine the supercooled liquid diffusivity from the intermixing of the isotopic layers. We find that the Kr permeation and the diffusivity of the supercooled liquid are directly and quantitatively correlated. These results validate the rare-gas permeation technique as a tool for probing the diffusivity of supercooled liquids.

Liquid-like thermal conduction in intercalated layered crystalline solids

NASA Astrophysics Data System (ADS)

Li, B.; Wang, H.; Kawakita, Y.; Zhang, Q.; Feygenson, M.; Yu, H. L.; Wu, D.; Ohara, K.; Kikuchi, T.; Shibata, K.; Yamada, T.; Ning, X. K.; Chen, Y.; He, J. Q.; Vaknin, D.; Wu, R. Q.; Nakajima, K.; Kanatzidis, M. G.

2018-03-01

As a generic property, all substances transfer heat through microscopic collisions of constituent particles1. A solid conducts heat through both transverse and longitudinal acoustic phonons, but a liquid employs only longitudinal vibrations2,3. As a result, a solid is usually thermally more conductive than a liquid. In canonical viewpoints, such a difference also serves as the dynamic signature distinguishing a solid from a liquid. Here, we report liquid-like thermal conduction observed in the crystalline AgCrSe2. The transverse acoustic phonons are completely suppressed by the ultrafast dynamic disorder while the longitudinal acoustic phonons are strongly scattered but survive, and are thus responsible for the intrinsically ultralow thermal conductivity. This scenario is applicable to a wide variety of layered compounds with heavy intercalants in the van der Waals gaps, manifesting a broad implication on suppressing thermal conduction. These microscopic insights might reshape the fundamental understanding on thermal transport properties of matter and open up a general opportunity to optimize performances of thermoelectrics.

Liquid-like thermal conduction in intercalated layered crystalline solids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, B.; Wang, H.; Kawakita, Y.

As a generic property, all substances transfer heat through microscopic collisions of constituent particles. A solid conducts heat through both transverse and longitudinal acoustic phonons, but a liquid employs only longitudinal vibrations. As a result, a solid is usually thermally more conductive than a liquid. In canonical viewpoints, such a difference also serves as the dynamic signature distinguishing a solid from a liquid. Here in this work, we report liquid-like thermal conduction observed in the crystalline AgCrSe 2. The transverse acoustic phonons are completely suppressed by the ultrafast dynamic disorder while the longitudinal acoustic phonons are strongly scattered but survive,more » and are thus responsible for the intrinsically ultralow thermal conductivity. This scenario is applicable to a wide variety of layered compounds with heavy intercalants in the van der Waals gaps, manifesting a broad implication on suppressing thermal conduction. Finally, these microscopic insights might reshape the fundamental understanding on thermal transport properties of matter and open up a general opportunity to optimize performances of thermoelectrics.« less

Reusable crucible for containing corrosive liquids

DOEpatents

de Pruneda, Jean A. H.

1995-01-01

A reusable, non-wetting, corrosion-resistant material suitable for containment of corrosive liquids is formed of a tantalum or tantalum alloy substrate that is permeated with carbon atoms. The substrate is carburized to form surface layers of TaC and Ta.sub.2 C, and then is heated at high temperature under vacuum until the carbon atoms in the carbide layers diffuse throughout the substrate to form a solid solution of carbon atoms randomly interspersed in the tantalum or tantalum alloy lattice.

Reusable crucible for containing corrosive liquids

DOEpatents

Pruneda, J.A.H. de.

1995-01-24

A reusable, non-wetting, corrosion-resistant material suitable for containment of corrosive liquids is formed of a tantalum or tantalum alloy substrate that is permeated with carbon atoms. The substrate is carburized to form surface layers of TaC and Ta[sub 2]C, and then is heated at high temperature under vacuum until the carbon atoms in the carbide layers diffuse throughout the substrate to form a solid solution of carbon atoms randomly interspersed in the tantalum or tantalum alloy lattice. 10 figures.

Internal insulation system development

NASA Technical Reports Server (NTRS)

Gille, J. P.

1973-01-01

The development of an internal insulation system for cryogenic liquids is described. The insulation system is based on a gas layer concept in which capillary or surface tension effects are used to maintain a stable gas layer within a cellular core structure between the tank wall and the contained cryogen. In this work, a 1.8 meter diameter tank was insulated and tested with liquid hydrogen. Ability to withstand cycling of the aluminum tank wall to 450 K was a design and test condition.

SELF SINTERING OF RADIOACTIVE WASTES

DOEpatents

McVay, T.N.; Johnson, J.R.; Struxness, E.G.; Morgan, K.Z.

1959-12-29

A method is described for disposal of radioactive liquid waste materials. The wastes are mixed with clays and fluxes to form a ceramic slip and disposed in a thermally insulated container in a layer. The temperature of the layer rises due to conversion of the energy of radioactivity to heat boillng off the liquid to fomn a dry mass. The dry mass is then covered with thermal insulation, and the mass is self-sintered into a leach-resistant ceramic cake by further conversion of the energy of radioactivity to heat.

Fat Layer from Medullary Canal Reamer Aspirate for Potential Use as a Supplemental Osteoinductive Bone Graft Material.

PubMed

Sinclair, Sarina S Kay; Horton, C Olsen; Jeray, Kyle J; Tanner, Stephanie L; Burgl, Karen J L

2015-01-01

Mesenchymal stem cells (MSCs) are of therapeutic interest to clinicians and researchers, as they have been shown to augment the osteogenic properties of bone grafts. MSCs are known to be prevalent in bone marrow, but are still limited in numbers. Hence, additional sources of MSCs are beneficial to increasing grafting potential. Aspirate material collected using the Reamer/Irrigator/Aspirator (RIA) device (Synthes; Paoli, PA) during reaming of the femoral shaft consists of three main components: bone fragments, liquid flow-through, and a fat layer. Currently, only the bone and liquid layers have been examined for osteoinductive elements, and the bone fragments are exclusively used as autologous bone graft. In the present study, a method to promote cellular outgrowth, tapping proliferative capacity from the previously discarded fatty layer of RIA aspirate, is described. Proliferating cells were successfully isolated from the bone and fatty layers of a consenting patient and found to be viable after liquid nitrogen storage. The osteogenic differentiation potential of the cells isolated from the fat and bone layers was assessed. Cells from both layers of the aspirate expressed statistically significant levels (p < 0.05) of the bone cell marker alkaline phosphatase compared to the control cells, suggesting differentiation along the osteoblastic pathway. Results from this pilot study indicate that the traditionally discarded fatty element of RIA aspirate may be a source of MSCs with bone-forming capabilities and the described isolation technique is effective. Combining the aspirate fatty and bony elements may enhance the clinical success of the RIA autograft.

Nonlinear dynamics of mushy layers induced by external stochastic fluctuations.

PubMed

Alexandrov, Dmitri V; Bashkirtseva, Irina A; Ryashko, Lev B

2018-02-28

The time-dependent process of directional crystallization in the presence of a mushy layer is considered with allowance for arbitrary fluctuations in the atmospheric temperature and friction velocity. A nonlinear set of mushy layer equations and boundary conditions is solved analytically when the heat and mass fluxes at the boundary between the mushy layer and liquid phase are induced by turbulent motion in the liquid and, as a result, have the corresponding convective form. Namely, the 'solid phase-mushy layer' and 'mushy layer-liquid phase' phase transition boundaries as well as the solid fraction, temperature and concentration (salinity) distributions are found. If the atmospheric temperature and friction velocity are constant, the analytical solution takes a parametric form. In the more common case when they represent arbitrary functions of time, the analytical solution is given by means of the standard Cauchy problem. The deterministic and stochastic behaviour of the phase transition process is analysed on the basis of the obtained analytical solutions. In the case of stochastic fluctuations in the atmospheric temperature and friction velocity, the phase transition interfaces (mushy layer boundaries) move faster than in the deterministic case. A cumulative effect of these noise contributions is revealed as well. In other words, when the atmospheric temperature and friction velocity fluctuate simultaneously due to the influence of different external processes and phenomena, the phase transition boundaries move even faster. This article is part of the theme issue 'From atomistic interfaces to dendritic patterns'.This article is part of the theme issue 'From atomistic interfaces to dendritic patterns'. © 2018 The Author(s).

Structure and chemical composition of layers adsorbed at interfaces with champagne.

PubMed

Aguié-Béghin, V; Adriaensen, Y; Péron, N; Valade, M; Rouxhet, P; Douillard, R

2009-11-11

The structure and the chemical composition of the layer adsorbed at interfaces involving champagne have been investigated using native champagne, as well as ultrafiltrate (UFch) and ultraconcentrate (UCch) obtained by ultrafiltration with a 10(4) nominal molar mass cutoff. The layer adsorbed at the air/liquid interface was examined by surface tension and ellipsometry kinetic measurements. Brewster angle microscopy demonstrated that the layer formed on polystyrene by adsorption or drop evaporation was heterogeneous, with a domain structure presenting similarities with the layer adsorbed at the air/liquid interface. The surface chemical composition of polystyrene with the adlayer was determined by X-ray photoelectron spectroscopy (XPS). The contribution of champagne constituents varied according to the liquid (native, UFch, and UCch) and to the procedure of adlayer formation (evaporation, adsorption, and adsorption + rinsing). However, their chemical composition was not significantly influenced either by ultrafiltration or by the procedure of deposition on polystyrene. Modeling this composition in terms of classes of model compounds gave approximately 35% (w/w) of proteins and 65% (w/w) of polysaccharides. In the adlayer, the carboxyl groups or esters represent about 18% of carbon due to nonpolypeptidic compounds, indicating the presence of either uronic acids in the complex structure of pectic polysaccharides or of polyphenolic esters. This structural and chemical information and its relationship with the experimental procedures indicate that proteins alone cannot be used as a realistic model for the macromolecules forming the adsorption layer of champagne. Polysaccharides, the other major macromolecular components of champagne wine, are assembled with proteins at the interfaces, in agreement with the heterogeneous character of the adsorbed layer at interfaces.

Longwave Stability of Two Liquid Layers Coating Both Sides of a Thick Wall in the Absence of Gravity

NASA Astrophysics Data System (ADS)

Dávalos-Orozco, L. A.

2018-05-01

A system of two coupled nonlinear equations was calculated to describe the thermocapillary evolution of the free surface deformations of two liquid layers coating both sides of a wall of finite thickness and thermal conductivity in the absence of gravity. The equations were obtained under the small wavenumber approximation. A temperature gradient appears perpendicular to the liquid-wall-liquid system due to the temperature difference between the atmospheres outside the free surfaces of both fluid layers. The linear growth rate of the system was investigated with respect to a variety of parameters. Under some conditions, two stationary modes and one oscillatory mode between them were found. The second stationary mode was concluded to be always stable. It was also found that under different conditions only stationary convection is possible. These results depended on the relative thickness of the two fluid films. It is of interest to know if the coupled free surface perturbations presented a nonlinear sinuous or varicose mode. Thus, a two-dimensional numerical analysis was performed to find out which conditions lead to the sinuous or to the varicose mode of instability.

Drop impact on thin liquid films using TIRM

NASA Astrophysics Data System (ADS)

Pack, Min; Ying Sun Team

2015-11-01

Drop impact on thin liquid films is relevant to a number of industrial processes such as pesticide spraying and repellent surface research such as self-cleaning applications. In this study, we systematically investigate the drop impact dynamics on thin liquid films on plain glass substrates by varying the film thickness, viscosity and impact velocity. High speed imaging is used to track the droplet morphology and trajectory over time as well as observing instability developments at high Weber number impacts. Moreover, the air layer between the drop and thin film upon drop impact is probed by total internal reflection microscopy (TIRM) where the grayscale intensity is used to measure the air layer thickness and spreading radius over time. For low We impact on thick films (We ~ 10), the effect of the air entrainment is pronounced where the adhesion of the droplet to the wall is delayed by the air depletion and liquid film drainage, whereas for high We impact (We >100) the air layer is no longer formed and instead, the drop contact with the wall is limited only to the film drainage for all film thicknesses. In addition, the maximum spreading radius of the droplet is analyzed for varying thin film thickness and viscosity.

Faraday instability on patterned surfaces

NASA Astrophysics Data System (ADS)

Feng, Jie; Rubinstein, Gregory; Jacobi, Ian; Stone, Howard

2013-11-01

We show how micro-scale surface patterning can be used to control the onset of the Faraday instability in thin liquid films. It is well known that when a liquid film on a planar substrate is subject to sufficient vibrational accelerations, the free surface destabilizes, exhibiting a family of non-linear standing waves. This instability remains a canonical problem in the study of spontaneous pattern formation, but also has practical uses. For example, the surface waves induced by the Faraday instability have been studied as a means of enhanced damping for mechanical vibrations (Genevaux et al. 2009). Also the streaming within the unstable layer has been used as a method for distributing heterogeneous cell cultures on growth medium (Takagi et al. 2002). In each of these applications, the roughness of the substrate significantly affects the unstable flow field. We consider the effect of patterned substrates on the onset and behavior of the Faraday instability over a range of pattern geometries and feature heights where the liquid layer is thicker than the pattern height. Also, we describe a physical model for the influence of patterned roughness on the destabilization of a liquid layer in order to improve the design of practical systems which exploit the Faraday instability.

Foam shell cryogenic ICF target

DOEpatents

Darling, Dale H.

1987-01-01

A uniform cryogenic layer of DT fuel is maintained in a fusion target having a low density, small pore size, low Z rigid foam shell saturated with liquid DT fuel. Capillary action prevents gravitational slumping of the fuel layer. The saturated shell may be cooled to produce a solid fuel layer.

Superhydrophobic coated apparatus for liquid purification by evaporative condensation

DOEpatents

Simpson, John T; McNeany, Steve R; Dinsmore, Thomas V; Hunter, Scott R; Ivanov, Ilia N

2014-03-11

Disclosed are examples of apparatuses for evaporative purification of a contaminated liquid. In each example, there is a first vessel for storing the contaminated fluid. The first vessel includes a surface coated with a layer of superhydrophobic material and the surface is at least partially in contact with the contaminated liquid. The contaminants do not adhere to the surface as the purified liquid evaporates, thus simplifying maintenance of the apparatus.

Labyrinthine flows across multilayer graphene-based membranes

NASA Astrophysics Data System (ADS)

Yoshida, Hiroaki

Graphene-based materials have recently found extremely wide applications for fluidic purposes thanks to remarkable developments in micro-/nano-fabrication techniques. In particular, high permeability and specific selectivity have been reported for these graphene-based membranes, such as the graphene-oxide membranes, with however controversial experimental results. There is therefore an urgent need to propose a theoretical framework of fluid transport in these architectures in order to rationalize the experimental results.In this presentation, we report a theoretical study of mass transport across multilayer graphene based membranes, which we benchmark by atomic-scale molecular dynamics. Specifically, we consider the water flow across multiple graphene layers with an inter-layer distance ranging from sub-nanometer to a few nanometers. The graphene layers have nanoslits aligned in a staggered fashion, and thus the water flows involve multiple twists and turns. We compare the continuum model predictions for the permeability with the lattice Boltzmann calculations and molecular dynamics simulations. The highlight is that, in spite of extreme confinement, the permeability across the graphene-based membrane is quantitatively predicted on the basis of a properly designed continuum model. The framework of this study constitutes a benchmark to which we compare favourably published experimental data.In addition, flow properties of a water-ethanol mixture are presented, demonstrating the possibility of a novel separation technique. While the membrane is permeable to both pure liquids, it exhibits a counter-intuitive ``self-semi-permeability'' to water in the presence of the mixture. This suggests a robust and versatile membrane-based separation method built on a pressure-driven reverse-osmosis process, which is considerably less energy consuming than distillation processes. The author acknowledges the ERC project Micromegas and the ANR projects BlueEnergy and Equip@Meso.

Physical mechanism for flat-to-lenticular lens conversion in homogeneous liquid crystal cell with periodically undulated electrode.

PubMed

Na, Jun-Hee; Park, Seung Chul; Kim, Se-Um; Choi, Yoonseuk; Lee, Sin-Doo

2012-01-16

A convertible lenticular liquid crystal (LC) lens architecture is demonstrated using an index-matched planarization layer on a periodically undulated electrode for the homogeneous alignment of an LC. It is found that the in-plane component of the electric field by the undulated electrode plays a primary role in the flat-to-lens effect while the out-of-plane component contributes to the anchoring enhancement of the LC molecules in the surface layer. Our LC device having an index-matched planarization layer on the undulated electrode is capable of achieving the electrical tunability from the flat surface to the lenticular lens suitable for 2D/3D convertible displays.

Tilted Orientation of Photochromic Dyes with Guest-Host Effect of Liquid Crystalline Polymer Matrix for Electrical UV Sensing

PubMed Central

Ranjkesh, Amid; Park, Min-Kyu; Park, Do Hyuk; Park, Ji-Sub; Choi, Jun-Chan; Kim, Sung-Hoon; Kim, Hak-Rin

2015-01-01

We propose a highly oriented photochromic dye film for an ultraviolet (UV)-sensing layer, where spirooxazine (SO) derivatives are aligned with the liquid crystalline UV-curable reactive mesogens (RM) using a guest-host effect. For effective electrical UV sensing with a simple metal-insulator-metal structure, our results show that the UV-induced switchable dipole moment amount of the SO derivatives is high; however, their tilting orientation should be controlled. Compared to the dielectric layer with the nearly planar SO dye orientation, the photochromic dielectric layer with the moderately tilted dye orientation shows more than seven times higher the UV-induced capacitance variation. PMID:26729116

Electrowetting on polymer dispersed liquid crystal

NASA Astrophysics Data System (ADS)

Fan, Shih-Kang; Chiu, Cheng-Pu; Lin, Jing-Wei

2009-04-01

Polymer dispersed liquid crystal (PDLC) is used as a dielectric layer in electrowetting. By applying voltage between a liquid droplet and the electrode underlying PDLC, electrowetting occurs at the liquid/PDLC interface accompanied with electro-optic responses of the reoriented LC droplets embedded in PDLC. Two basic experiments investigating the electrowetting by sessile water droplets and the electro-optic effects through squeezed water droplets were design and performed. The basic functions of a liquid lens and droplet manipulations, including transporting, splitting, and merging, were demonstrated.

Transmission electron microscope cells for use with liquid samples

DOEpatents

Khalid, Waqas; Alivisatos, Paul A.; Zettl, Alexander K.

2016-08-09

This disclosure provides systems, methods, and devices related to transmission electron microscopy cells for use with liquids. In one aspect a device includes a substrate, a first graphene layer, and a second graphene layer. The substrate has a first surface and a second surface. The first surface defines a first channel, a second channel, and an outlet channel. The first channel and the second channel are joined to the outlet channel. The outlet channel defines a viewport region forming a though hole in the substrate. The first graphene layer overlays the first surface of the substrate, including an interior area of the first channel, the second channel, and the outlet channel. The second graphene layer overlays the first surface of the substrate, including open regions defined by the first channel, the second channel, and the outlet channel.

Boundary layer integral matrix procedure: Verification of models

NASA Technical Reports Server (NTRS)

Bonnett, W. S.; Evans, R. M.

1977-01-01

The three turbulent models currently available in the JANNAF version of the Aerotherm Boundary Layer Integral Matrix Procedure (BLIMP-J) code were studied. The BLIMP-J program is the standard prediction method for boundary layer effects in liquid rocket engine thrust chambers. Experimental data from flow fields with large edge-to-wall temperature ratios are compared to the predictions of the three turbulence models contained in BLIMP-J. In addition, test conditions necessary to generate additional data on a flat plate or in a nozzle are given. It is concluded that the Cebeci-Smith turbulence model be the recommended model for the prediction of boundary layer effects in liquid rocket engines. In addition, the effects of homogeneous chemical reaction kinetics were examined for a hydrogen/oxygen system. Results show that for most flows, kinetics are probably only significant for stoichiometric mixture ratios.

Nitrogen-doped carbon capsules via poly(ionic liquid)-based layer-by-layer assembly.

PubMed

Zhao, Qiang; Fellinger, Tim-Patrick; Antonietti, Markus; Yuan, Jiayin

2012-07-13

Layer-by-layer (LbL) assembly technique is applied for the first time for the preparation of nitrogen-doped carbon capsules. This approach uses colloid silica as template and two polymeric deposition components, that is, poly(ammonium acrylate) and a poly (ionic liquid) poly(3-cyanomethyl-1-vinylimidazolium bromide), which acts as both the carbon precursor and nitrogen source. Nitrogen-doped carbon capsules are prepared successfully by polymer wrapping, subsequent carbonization and template removal. The as-synthesized carbon capsules contain ≈7 wt% of nitrogen and have a structured specific surface area of 423 m(2) g(-1). Their application as supercapacitor has been briefly introduced. This work proves that LbL assembly methodology is available for preparing carbon structures of complex morphology. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Liquid-phase-deposited siloxane-based capping layers for silicon solar cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Veith-Wolf, Boris; Wang, Jianhui; Hannu-Kuure, Milja

2015-02-02

We apply non-vacuum processing to deposit dielectric capping layers on top of ultrathin atomic-layer-deposited aluminum oxide (AlO{sub x}) films, used for the rear surface passivation of high-efficiency crystalline silicon solar cells. We examine various siloxane-based liquid-phase-deposited (LPD) materials. Our optimized AlO{sub x}/LPD stacks show an excellent thermal and chemical stability against aluminum metal paste, as demonstrated by measured surface recombination velocities below 10 cm/s on 1.3 Ωcm p-type silicon wafers after firing in a belt-line furnace with screen-printed aluminum paste on top. Implementation of the optimized LPD layers into an industrial-type screen-printing solar cell process results in energy conversion efficiencies ofmore » up to 19.8% on p-type Czochralski silicon.« less

High performance liquid chromatography: Tandem mass spectrometric determination of cisplatin levels in different visceral pleura layers of rats.

PubMed

Xia, Hui; Zhang, Wen; Li, Yingjie; Yu, Changhai

2015-05-01

The aim of the present study was to investigate the concentration of cisplatin in different layers of the visceral pleura in rats, following drug administration. In this study, a sensitive and specific liquid chromatography method coupled with electrospray ionization-tandem mass spectrometry was established to investigate the disposition of cisplatin in different layers of the visceral pleura in rats. Methodological data, including specificity, linearity, accuracy, recovery, precision and lower limits of quantification, confirmed that this novel method may be used to efficiently quantify the cisplatin concentrations in visceral pleura of rats following administration of the drug. Furthermore, the results demonstrated that the desired drug concentration was not achieved in the outer or inner elastic layers of the visceral pleura following injection with cisplatin through various administration methods.

Bent-core fiber structure: Experimental and theoretical studies of fiber stability

NASA Astrophysics Data System (ADS)

Bailey, C.; Gartland, E.; Jakli, A.

2007-03-01

Recent studies have shown that bent core liquid crystals in the B7 and B2 phases can form stable freestanding fibers with a so called ``jelly-roll'' layer configuration, which means that the smectic layers would be arranged in concentric cylindrical shells. This configuration shows layer curvature is necessary for fiber stability. Classically this effect would destabilize the fiber configuration because of the energy cost of layer distortions and surface tension. We propose a model that can predict fiber stability in the experimentally observed range of a few micrometers, by assuming that layer curvature can be stabilized by including a term dealing with the linear divergence of the polarization direction if the polarization is allowed to have a component normal to the smectic layers. We show that this term can stabilize the fiber configuration if its strength is larger than the surface tension. We also propose an entropic model to explain the strength of this term by considering steric effects. Finally we will take results from this model and apply them to better understand experimental findings of bent-core fibers. Financial support by NSF FRG under contract DMS-0456221. Prof. Daniel Phillips, Particia Bauman and Jie Shen at Purdue Univ., Prof. Maria Carme Calderer at Univ. of Minnesota, and Prof. Jonathan Selinger at Kent State Univ. Liou Qiu and Dr. O.D. Lavrentovich, Characterization Facilities, Liquid Crystal Institute, Kent State Univ. Julie Kim and Dr. Quan Li, Chemical Synthesis Facilities, Liquid Crystal Institute, Kent State Univ.

Millimeter-wave monolithic diode-grid frequency multiplier

NASA Technical Reports Server (NTRS)

Maserjian, Joseph (Inventor)

1990-01-01

A semiconductor diode structure useful for harmonic generation of millimeter or submillimeter wave radiation from a fundamental input wave is fabricated on a GaAs substrate. A heavily doped layer of n(sup ++) GaAs is produced on the substrate and then a layer of intrinsic GaAs on said heavily doped layer on top of which a sheet of heavy doping (++) is produced. A thin layer of intrinsic GaAs grown over the sheet is capped with two metal contacts separated by a gap to produce two diodes connected back to back through the n(sup ++) layer for multiplication of frequency by an odd multiple. If only one metal contact caps the thin layer of intrinsic GaAs, the second diode contact is produced to connect to the n(sup ++) layer for multiplication of frequency by an even number. The odd or even frequency multiple is selected by a filter. A phased array of diodes in a grid will increase the power of the higher frequency generated.

Characterization of the Electric Double Layer Formation Dynamics of a Metal/Ionic Liquid/Metal Structure.

PubMed

Schmidt, Elliot; Shi, Sha; Ruden, P Paul; Frisbie, C Daniel

2016-06-15

Although ionic liquids (ILs) have been used extensively in recent years as a high-capacitance "dielectric" in electric double layer transistors, the dynamics of the double layer formation have remained relatively unexplored. Better understanding of the dynamics and relaxation processes involved in electric double layer formation will guide device optimization, particularly with regard to switching speed. In this paper, we explore the dynamical characteristics of an IL in a metal/ionic liquid/metal (M/IL/M) capacitor. In particular, we examine a Au/IL/Au structure where the IL is 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate. The experiments consist of frequency-dependent impedance measurements and time-dependent current vs voltage measurements for applied linear voltage ramps and abrupt voltage steps. The parameters of an equivalent circuit model are determined by fits to the impedance vs frequency data and subsequently verified by calculating the current vs voltage characteristics for the applied potential profiles. The data analysis indicates that the dynamics of the structure are characterized by a wide distribution of relaxation times spanning the range of less than microseconds to longer than seconds. Possible causes for these time scales are discussed.

Scaling of Liquid DT Layer Capsules to an ICF Burning Plasma

NASA Astrophysics Data System (ADS)

Olson, R. E.; Peterson, R. R.; Haines, B. M.; Yi, S. A.; Bradley, P. A.; Zylstra, A. B.; Kline, J. L.; Leeper, R. J.; Batha, S. H.

2017-10-01

Recent experiments at the NIF demonstrated cryogenic liquid DT layer ICF implosions. Unlike DT ice layer implosions, DT liquid layer designs can operate with low-to-moderate convergence ratio (12

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

NASA Astrophysics Data System (ADS)

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

2017-09-01

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

Optimization of ferroelectric liquid crystal optically addressed spatial light modulator performance

NASA Astrophysics Data System (ADS)

Perennes, Frederic; Crossland, William A.

1997-08-01

The switching mechanisms of ferroelectric liquid crystal optically addressed spatial light modulators (OASLMs) using a photosensitive structure made of an intrinsic amorphous silicon layer sandwiched in between an indium tin oxide coated glass sheet and a reflective metal layer are reviewed. Devices based on photoconductor and photodiode layers are briefly reviewed and attention is focused on pixelated metal mirror devices, which offer fast switching and good optical characteristics with the same sensitivity range as the photodiode OASLMs. They are particularly suitable for high frame rate SLMs with intense read beams. Optimum drive conditions for this type of device are considered. An equivalent electrical circuit is proposed for the photosensitive structure and the voltage drop across the liquid crystal layer is investigated and related to the optical response of the device. Experimental work is carried out to demonstrate the validity of our equivalent circuit. We show that the synchronization of a light source with the case pulse enables the OASLM to work at frame rates of a few kilohertz. We also demonstrate that the exact synchronization of the write light source with the write pulse enhances the potential memory of the device.

X-ray Imaging of Transplanar Liquid Transport Mechanisms in Single Layer Textiles.

PubMed

Zhang, Gannian; Parwani, Rachna; Stone, Corinne A; Barber, Asa H; Botto, Lorenzo

2017-10-31

Understanding the penetration of liquids within textile fibers is critical for the development of next-generation smart textiles. Despite substantial research on liquid penetration in the plane of the textile, little is known about how the liquid penetrates in the thickness direction. Here we report a time-resolved high-resolution X-ray measurement of the motion of the liquid-air interface within a single layer textile, as the liquid is transported across the textile thickness following the deposition of a droplet. The measurement of the time-dependent position of the liquid meniscus is made possible by the use of ultrahigh viscosity liquids (dynamic viscosity from 10 5 to 2.5 × 10 6  times larger than water). This approach enables imaging due to the slow penetration kinetics. Imaging results suggest a three-stage penetration process with each stage being associated with one of the three types of capillary channels existing in the textile geometry, providing insights into the effect of the textile structure on the path of the three-dimensional liquid meniscus. One dimensional kinetics studies show that our data for the transplanar penetration depth Δx L vs time do not conform to a power law, and that the measured rate of penetration for long times is smaller than that predicted by Lucas-Washburn kinetics, challenging commonly held assumptions regarding the validity of power laws when applied to relatively thin textiles.

Dual-layer electrode-driven liquid crystal lens with electrically tunable focal length and focal plane

NASA Astrophysics Data System (ADS)

Zhang, Y. A.; Lin, C. F.; Lin, J. P.; Zeng, X. Y.; Yan, Q.; Zhou, X. T.; Guo, T. L.

2018-04-01

Electric-field-driven liquid crystal (ELC) lens with tunable focal length and their depth of field has been extensively applied in 3D display and imaging systems. In this work, a dual-layer electrode-driven liquid crystal (DELC) lens with electrically tunable focal length and controllable focal plane is demonstrated. ITO-SiO2-AZO electrodes with the dual-layer staggered structure on the top substrate are used as driven electrodes within a LC cell, which permits the establishment of an alternative controllability. The focal length of the DELC lens can be adjusted from 1.41 cm to 0.29 cm when the operating voltage changes from 15 V to 40 V. Furthermore, the focal plane of the DELC lens can selectively move by changing the driving method of the applied voltage to the next driven electrodes. This work demonstrates that the DELC lens has potential applications in imaging systems because of electrically tunable focal length and controllable focal plane.

Pore network modeling to explore the effects of compression on multiphase transport in polymer electrolyte membrane fuel cell gas diffusion layers

NASA Astrophysics Data System (ADS)

Fazeli, Mohammadreza; Hinebaugh, James; Fishman, Zachary; Tötzke, Christian; Lehnert, Werner; Manke, Ingo; Bazylak, Aimy

2016-12-01

Understanding how compression affects the distribution of liquid water and gaseous oxygen in the polymer electrolyte membrane fuel cell gas diffusion layer (GDL) is vital for informing the design of improved porous materials for effective water management strategies. Pore networks extracted from synchrotron-based micro-computed tomography images of compressed GDLs were employed to simulate liquid water transport in GDL materials over a range of compression pressures. The oxygen transport resistance was predicted for each sample under dry and partially saturated conditions. A favorable GDL compression value for a preferred liquid water distribution and oxygen diffusion was found for Toray TGP-H-090 (10%), yet an optimum compression value was not recognized for SGL Sigracet 25BC. SGL Sigracet 25BC exhibited lower transport resistance values compared to Toray TGP-H-090, and this is attributed to the additional diffusion pathways provided by the microporous layer (MPL), an effect that is particularly significant under partially saturated conditions.

Prospect of life on cold planets with low atmospheric pressures

NASA Astrophysics Data System (ADS)

Pavlov, A. A.; Vdovina, M.

2009-12-01

Stable liquid water on the surface of a planet has been viewed as the major requirement for a habitable planet. Such approach would exclude planets with low atmospheric pressures and cold mean surface temperatures (like present Mars) as potential candidates for extraterrestrial life search. Here we explore a possibility of the liquid water formation in the extremely shallow (1-3 cm) subsurface layer under low atmospheric pressures (0.1-10 mbar) and low average surface temperatures (~-30 C). During brief periods of simulated daylight warming the shallow subsurface ice sublimates, the water vapor can diffuse through the porous surface layer of soil temporarily producing supersaturated conditions in the soil, which lead to the formation of liquid films. We show that non-extremophile terrestrial microorganisms (Vibrio sp.) can grow and reproduce under such conditions. The necessary conditions for metabolism and reproduction are the sublimation of ground ice through a thin layer of soil and short episodes of warm temperatures at the planetary surface.

Shear bond strengths of an indirect composite layering material to a tribochemically silica-coated zirconia framework material.

PubMed

Iwasaki, Taro; Komine, Futoshi; Fushiki, Ryosuke; Kubochi, Kei; Shinohara, Mitsuyo; Matsumura, Hideo

2016-01-01

This study evaluated shear bond strengths of a layering indirect composite material to a zirconia framework material treated with tribochemical silica coating. Zirconia disks were divided into two groups: ZR-PRE (airborne-particle abrasion) and ZR-PLU (tribochemical silica coating). Indirect composite was bonded to zirconia treated with one of the following primers: Clearfil Ceramic Primer (CCP), Clearfil Mega Bond Primer with Clearfil Porcelain Bond Activator (MGP+Act), ESPE-Sil (SIL), Estenia Opaque Primer, MR. Bond, Super-Bond PZ Primer Liquid A with Liquid B (PZA+PZB), and Super-Bond PZ Primer Liquid B (PZB), or no treatment. Shear bond testing was performed at 0 and 20,000 thermocycles. Post-thermocycling shear bond strengths of ZR-PLU were higher than those of ZR-PRE in CCP, MGP+Act, SIL, PZA+PZB, and PZB groups. Application of silane yielded better durable bond strengths of a layering indirect composite material to a tribochemically silica-coated zirconia framework material.

Comparison of 193 nm and 308 nm laser liquid printing by shadowgraphy imaging

NASA Astrophysics Data System (ADS)

Palla-Papavlu, A.; Shaw-Stewart, J.; Mattle, T.; Dinca, V.; Lippert, T.; Wokaun, A.; Dinescu, M.

2013-08-01

Over the last years laser-induced forward transfer has emerged as a versatile and powerful tool for engineering surfaces with active compounds. Soft, easily damageable materials can be transferred using a triazene polymer as a sacrificial layer which acts as a pressure generator and at the same time protects the material from direct laser irradiation. To understand and optimize the transfer process of biomolecules in liquid solution by using an intermediate triazene polymer photosensitive layer, shadowgraphy imaging is carried out. Two laser systems i.e. an ArF laser operating at 193 nm and a XeCl laser operating at 308 nm are applied for the transfer. Solutions with 50% v/v glycerol concentration are prepared and the influence of the triazene polymer sacrificial layer thickness (60 nm) on the deposits is studied. The shadowgraphy images reveal a pronounced difference between laser-induced forward transfer using 193 nm or 308 nm, i.e. very different shapes of the ejected liquid.

Multiple stage multiple filter hydrate store

DOEpatents

Bjorkman, H.K. Jr.

1983-05-31

An improved hydrate store for a metal halogen battery system is disclosed which employs a multiple stage, multiple filter means for separating the halogen hydrate from the liquid used in forming the hydrate. The filter means is constructed in the form of three separate sections which combine to substantially cover the interior surface of the store container. Exit conduit means is provided in association with the filter means for transmitting liquid passing through the filter means to a hydrate former subsystem. The hydrate former subsystem combines the halogen gas generated during the charging of the battery system with the liquid to form the hydrate in association with the store. Relief valve means is interposed in the exit conduit means for controlling the operation of the separate sections of the filter means, such that the liquid flow through the exit conduit means from each of the separate sections is controlled in a predetermined sequence. The three separate sections of the filter means operate in three discrete stages to provide a substantially uniform liquid flow to the hydrate former subsystem during the charging of the battery system. The separation of the liquid from the hydrate causes an increase in the density of the hydrate by concentrating the hydrate along the filter means. 7 figs.

Multiple stage multiple filter hydrate store

DOEpatents

Bjorkman, Jr., Harry K.

1983-05-31

An improved hydrate store for a metal halogen battery system is disclosed which employs a multiple stage, multiple filter means or separating the halogen hydrate from the liquid used in forming the hydrate. The filter means is constructed in the form of three separate sections which combine to substantially cover the interior surface of the store container. Exit conduit means is provided in association with the filter means for transmitting liquid passing through the filter means to a hydrate former subsystem. The hydrate former subsystem combines the halogen gas generated during the charging of the battery system with the liquid to form the hydrate in association with the store. Relief valve means is interposed in the exit conduit means for controlling the operation of the separate sections of the filter means, such that the liquid flow through the exit conduit means from each of the separate sections is controlled in a predetermined sequence. The three separate sections of the filter means operate in three discrete stages to provide a substantially uniform liquid flow to the hydrate former subsystem during the charging of the battery system. The separation of the liquid from the hydrate causes an increase in the density of the hydrate by concentrating the hydrate along the filter means.

Wavelength-tunable light shaping with cholesteric liquid crystal microlenses.

PubMed

Bayon, Chloé; Agez, Gonzague; Mitov, Michel

2014-06-21

The ability to guide light on the mesoscopic scale is important both scientifically and technologically. Especially relevant is the development of wavelength-tunable light-shaping microdevices. Here we demonstrate the use of cholesteric liquid crystal polygonal textures organized as an array of microlenses for this purpose. The beam shaping is controlled by tuning the wavelength of the incident light in the visible spectrum. By taking advantage of the self-organization property of liquid crystals, the structure of the lens and its optical response are tailored by changing the annealing time of the single layer material during a completely integrated one-step process. The intrinsic helical organization of the layer is the cause of the light shaping and not the shape of the surface as for conventional lenses. A new concept of light manipulation using the structure chirality of liquid crystals is demonstrated, which concerns soft matter photonic circuits to mould the light.

Boundary layers in turbulent convection for air, liquid gallium and liquid sodium

NASA Astrophysics Data System (ADS)

Scheel, Janet; Schumacher, Joerg

2017-11-01

The scaling of physical quantities that characterize the shape and dynamics of the viscous and thermal boundary layers with respect to the Rayleigh number will be presented for three series of three-dimensional high-resolution direct numerical simulations of Rayleigh-Benard convection (RBC) in a closed cylindrical cell of aspect ratio one. The simulations have been conducted for convection in air at a Prandtl number Pr = 0.7, in liquid gallium at Pr = 0.021 and in liquid sodium at Pr = 0.005. Then we discuss three statistical analysis methods which have been developed to predict the transition of turbulent RBC into the ultimate regime. The methods are based on the large-scale properties of the velocity profile. All three methods indicate that the range of critical Rayleigh numbers is shifted to smaller magnitudes as the Prandtl number becomes smaller. This work is supported by the Priority Programme SPP 1881 of the Deutsche Forschungsgemeinschaft.

Capillary trapping of particles in thin-film flows

NASA Astrophysics Data System (ADS)

Dressaire, Emilie; Gomez, Michael; Colnet, Benedicte; Sauret, Alban

2017-11-01

When a thin layer of suspension flows over a substrate, some particles remain trapped on the solid surface. When the thickness of the liquid layer is comparable to the particle size, the particles deform the liquid interface, which leads to local interactions. These effects modify the transport of particles and the dynamics of the liquid films. Here, we characterize how capillary interactions affect the transport and deposition of non-Brownian particles moving in thin liquid films and the resulting loss of transported material. We focus on gravitational drainage flows, in which the film thickness becomes comparable to the particle size. Depending on the concentration of particles, we find that the drainage dynamics exhibits behavior that cannot be captured with a continuum model, due to the deposition of particles on the substrate. ANR-16-CE30-0009 & CNRS-PICS-07242 & ACS-PRF 55845-ND9.

Chitin Liquid-Crystal-Templated Oxide Semiconductor Aerogels.

PubMed

Chau, Trang The Lieu; Le, Dung Quang Tien; Le, Hoa Thi; Nguyen, Cuong Duc; Nguyen, Long Viet; Nguyen, Thanh-Dinh

2017-09-13

Chitin nanocrystals have been used as a liquid crystalline template to fabricate layered oxide semiconductor aerogels. Anisotropic chitin liquid crystals are transformed to sponge-like aerogels by hydrothermally cross-linked gelation and lyophilization-induced solidification. The hydrothermal gelation of chitin aqueous suspensions then proceeds with peroxotitanate to form hydrogel composites that recover to form aerogels after freeze-drying. The homogeneous peroxotitanate/chitin composites are calcined to generate freestanding titania aerogels that exhibit the nanostructural integrity of layered chitin template. Our extended investigations show that coassembling chitin nanocrystals with other metal-based precursors also yielded semiconductor aerogels of perovskite BaTiO 3 and CuO x nanocrystals. The potential of these materials is great to investigate these chitin sponges for biomedicine and these semiconductor aerogels for photocatalysis, gas sensing, and other applications. Our results present a new aerogel templating method of highly porous, ultralight materials with chitin liquid crystals.

Monodisperse, polymeric microspheres produced by irradiation of slowly thawing frozen drops

NASA Technical Reports Server (NTRS)

Rhim, Won-Kyu (Inventor); Hyson, Michael T. (Inventor); Chung, Sang-Kun (Inventor); Colvin, Michael S. (Inventor); Chang, Manchium (Inventor)

1991-01-01

Monodisperse, polymeric microspheres are formed by injecting uniformly shaped droplets of radiation polymerizable monomers, preferably a biocompatible monomer, having covalent binding sites such as hydroxyethylmethacrylate, into a zone, impressing a like charge on the droplet so that they mutually repel each other, spheroidizing the droplets within the zone and collecting the droplets in a pool of cryogenic liquid. As the droplets enter the liquid, they freeze into solid, glassy microspheres, which vaporizes a portion of the cryogenic liquid to form a layer. The like-charged microspheres, suspended within the layer, move to the edge of the vessel holding the pool, are discharged, fall and are collected. The collected microspheres are irradiated while frozen in the cryogenic liquid to form latent free radicals. The frozen microspheres are then slowly thawed to activate the free radicals which polymerize the monomer to form evenly-sized, evenly-shaped, monodisperse polymeric microspheres.

Oscillatory interfacial instability between miscible fluids

NASA Astrophysics Data System (ADS)

Shevtsova, Valentina; Gaponenko, Yuri; Mialdun, Aliaksandr; Torregrosa, Marita; Yasnou, Viktar

Interfacial instabilities occurring between two fluids are of fundamental interest in fluid dynamics, biological systems and engineering applications such as liquid storage, solvent extraction, oil recovery and mixing. Horizontal vibrations applied to stratified layers of immiscible liquids may generate spatially periodic waving of the interface, stationary in the reference frame of the vibrated cell, referred to as a "frozen wave". We present experimental evidence that frozen wave instability exists between two ordinary miscible liquids of similar densities and viscosities. At the experiments and at the numerical model, two superimposed layers of ordinary liquids, water-alcohol of different concentrations, are placed in a closed cavity in a gravitationally stable configuration. The density and viscosity of these fluids are somewhat similar. Similar to the immiscible fluids this instability has a threshold. When the value of forcing is increased the amplitudes of perturbations grow continuously displaying a saw-tooth structure. The decrease of gravity drastically changes the structure of frozen waves.

Performance of Liquid Phase Exfoliated Graphene As Electrochemical Double Layer Capacitors Electrodes

NASA Astrophysics Data System (ADS)

Huffstutler, Jacob; Wasala, Milinda; Richie, Julianna; Winchester, Andrew; Ghosh, Sujoy; Kar, Swastik; Talapatra, Saikat

2014-03-01

We will present the results of our investigations of electrochemical double layer capacitors (EDLCs) or supercapacitors (SC) fabricated using liquid-phase exfoliated graphene. Several electrolytes, such as aqueous potassium hydroxide KOH (6M), ionic 1-Butyl-3-methylimidazolium hexafluorophosphate [BMIM][PF6], and ionic 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate[BMP][FAP] were used. These EDLC's show good performance compared to other carbon nanomaterials based EDLC's devices. We found that the liquid phase exfoliated graphene based devices possess specific capacitance values as high as 262 F/g, when used with ionic liquid electrolyte[BMP][FAP], with power densities (~ 454 W/kg) and energy densities (~ 0.38Wh/kg). Further, these devices indicated rapid charge transfer response even without the use of any binders or specially prepared current collectors. A detailed electrochemical impedance spectroscopy analysis in order to understand the phenomenon of charge storage in these materials will be presented.

Flexible, liquid core light guide with focusing and light shaping attachments

DOEpatents

Wojcik, R.F.; Majewski, S.; Zorn, C.J.; Kross, B.

1999-04-20

A liquid light guide system for ultraviolet light is disclosed that has a light shaping arrangement for the emitted light, a stable liquid core and sheath and reliable and effective end closures. The end closures include a metal crimping arrangement that utilizes two layers of deformable materials to prevent cracking of endplugs. 19 figs.

Nature of solidification of nanoconfined organic liquid layers.

PubMed

Lang, X Y; Zhu, Y F; Jiang, Q

2007-01-30

A simple model is established for solidification of a nanoconfined liquid under nonequilibrium conditions. In terms of this model, the nature of solidification is the conjunct finite size and interface effects, which is directly related to the cooling rate or the relaxation time of the undercooled liquid. The model predictions are consistent with available experimental results.

Surface modification of poly(vinylidene fluoride) hollow fibre membranes for biogas purification in a gas-liquid membrane contactor system.

PubMed

Jin, Pengrui; Huang, Chuan; Li, Jiaxiang; Shen, Yadong; Wang, Liao

2017-11-01

The wetting of hollow fibre membranes decreases the performance of the liquid-gas membrane contactor for CO 2 capture in biogas upgrading. To solve this problem, in this work, a poly(vinylidene fluoride) (PVDF) hollow fibre membrane for a liquid-gas membrane contactor was coated with a superhydrophobic layer composed of a combination of hydrophobic SiO 2 nanoparticles and polydimethylsiloxane (PDMS) by the method of spray deposition. A rough layer of SiO 2 deposited on the PVDF membrane resulted in an enhanced surface hydrophobicity. The surface structure of the pristine PVDF significantly affected the homogeneity of the generated SiO 2 layer. A uniform surface coating on the PVDF upper layer resulted from the presence of micrometre and nanometre-sized roughness on the surface of the PVDF membrane, which was achieved with a SiO 2 concentration of 4.44 mg ml -1 (0.2 g/45 ml) in the coating solution. As a result, the water contact angle of the modified surface was recorded as 155 ± 3°, which is higher than that of the pristine surface. The high contact angle is advantageous for reducing the wetting of the membrane. Additional mass transfer resistance was introduced by the superhydrophobic layer. In addition, continuous CO 2 absorption tests were carried out in original and modified PVDF hollow fibre membrane contactors, using monoethanolamine (MEA) solution as the absorbent. A long-term stability test revealed that the modified PVDF hollow fibre membrane contactor was able to outperform the original membrane contactor and demonstrated outstanding long-term stability, suggesting that spray deposition is a promising approach to obtain superhydrophobic PVDF membranes for liquid-gas membrane absorption.