WorldWideScience

Sample records for dewetting process due

  1. On dewetting of thin films due to crystallization (crystallization dewetting).

    Science.gov (United States)

    Habibi, Mehran; Rahimzadeh, Amin; Eslamian, Morteza

    2016-03-01

    Drying and crystallization of a thin liquid film of an ionic or a similar solution can cause dewetting in the resulting thin solid film. This paper aims at investigating this type of dewetting, herein termed "crystallization dewetting", using PbI2 dissolved in organic solvents as the model solution. PbI2 solid films are usually used in X-ray detection and lead halide perovskite solar cells. In this work, PbI2 films are fabricated using spin coating and the effect of major parameters influencing the crystallization dewetting, including the type of the solvent, solution concentration, drying temperature, spin speed, as well as imposed vibration on the substrate are studied on dewetting, surface profile and coverage, using confocal scanning laser microscopy. Simplified hydrodynamic governing equations of crystallization in thin films are presented and using a mathematical representation of the process, it is phenomenologically demonstrated that crystallization dewetting occurs due to the absorption and consumption of the solution surrounding a growing crystal. Among the results, it is found that a low spin speed (high thickness), a high solution concentration and a low drying temperature promote crystal growth, and therefore crystallization dewetting. It is also shown that imposed vibration on the substrate can affect the crystal size and crystallization dewetting.

  2. Retardation of the dewetting process due to the addition of functional copolymers at polymer-polymer interfaces

    CERN Document Server

    Wunnicke, O; Lorenz-Haas, C; Leiner, V

    2002-01-01

    We studied the retardation of the dewetting process due to the addition of a functional copolymer in a polymer bilayer film. The model system consists of fully deuterated polystyrene (PS-d) on top of an amorphous polyamide (PA) sublayer on silicon substrates. Bilayer films were prepared with different content (0, 5, 10 and 30 vol. %) of a statistical copolymer (protonated styrene maleic anhydride acid (SMA2) containing 2% MA groups along the chain) being capable of forming hydrogen bonds with PA. The as-prepared as well as the annealed samples were investigated by neutron-reflectivity (NR) experiments, scanning force microscopy and optical microscopy. A significant retardation of dewetting is observed with the addition of SMA2. From model fits of NR curves the scattering length density profiles perpendicular to the sample surface were determined and an enrichment layer of SMA2 is detected. Retardation is explained by the intermixing of SMA2 and PS-d at the interface. (orig.)

  3. Visualization of nanosecond laser-induced dewetting, ablation and crystallization processes in thin silicon films

    Science.gov (United States)

    Qi, Dongfeng; Zhang, Zifeng; Yu, Xiaohan; Zhang, Yawen

    2018-06-01

    In the present work, nanosecond pulsed laser crystallization, dewetting and ablation of thin amorphous silicon films are investigated by time-resolved imaging. Laser pulses of 532 nm wavelength and 7 ns temporal width are irradiated on silicon film. Below the dewetting threshold, crystallization process happens after 400 ns laser irradiation in the spot central region. With the increasing of laser fluence, it is observed that the dewetting process does not conclude until 300 ns after the laser irradiation, forming droplet-like particles in the spot central region. At higher laser intensities, ablative material removal occurs in the spot center. Cylindrical rims are formed in the peripheral dewetting zone due to solidification of transported matter at about 500 ns following the laser pulse exposure.

  4. Transient Cooperative Processes in Dewetting Polymer Melts.

    Science.gov (United States)

    Chandran, Sivasurender; Reiter, Günter

    2016-02-26

    We compare the high velocity dewetting behavior, at elevated temperatures, of atactic polystyrene (aPS) and isotactic polystyrene (iPS) films, with the zero shear bulk viscosity (η_{bulk}) of aPS being approximately ten times larger than iPS. As expected, for aPS the apparent viscosity of the films (η_{f}) derived from high-shear dewetting is less than η_{bulk}, displaying a shear thinning behavior. Surprisingly, for iPS films, η_{f} is always larger than η_{bulk}, even at about 50 °C above the melting point, with η_{f}/η_{bulk} following an Arrhenius behavior. The corresponding activation energy of ∼160±10  kJ/mol for iPS films suggests a cooperative motion of segments which are aligned and agglomerated by fast dewetting.

  5. Examining Wetting and Dewetting Processes in Thin-films on Crystalline Substrates at the Nanoscale

    Science.gov (United States)

    Hihath, Sahar

    experimental observations. Second, the fundamental mechanisms that govern the onset of dewetting of thin metal films in both liquid and solid state are investigated. Dewetting processes are used in numerous technological applications. For instance, the dewetting of thin films on substrates is used for making spatially ordered nanoparticle arrays for use in plasmonics, nanophotonics, and magnetics. [1] In addition to dewetting applications in industry and research, dewetting processes have adverse impact on the reliability of semiconductor devices as it can limit the functionality of metal contacts utilized in transistors at elevated temperatures. The morphological changes during dewetting have been studied previously in plan-view by Scanning Electron Microscopy (SEM) after the annealing is completed, and in some cases in cross-section via real-time Transmission Electron Microscopy (TEM). However, due to temporal limitations of image acquisition in TEM, which is in the range of milliseconds, it has not been possible thus far to investigate the dynamics of the dewetting process with high-speed time resolution from nano- to micro-seconds. To gain insights into the fundamental mechanisms involved in dewetting, the early stages of the dewetting process were investigated via Dynamic Transmission Electron Microscopy (DTEM) with nanosecond time and nanometer spatial resolution. The experiments were performed on plan-view TEM samples consisting of nickel thin-films on (100) silicon substrates with a 2-3 nm thick native oxide. The laser ablation dynamics were captured, which involved liquid phase dewetting of the nickel film followed by substrate fracture and nanoscale particle expulsion. Finally, to capture the full dynamics of the dewetting process the experiments were performed on a system of nickel thin-films on (100) Strontium Titanate (STO) substrates. Samples of nickel thin-films on STO substrates have lower thermal expansion coefficient mismatch compared to the system discussed

  6. Assembly of Ge nanocrystals on SiO2 via a stress-induced dewetting process

    International Nuclear Information System (INIS)

    Sutter, E; Sutter, P

    2006-01-01

    We use epitaxial Ge islands on silicon-on-insulator (001) to initiate and drive the dewetting of the ultrathin ( 2 layer and transforms the Ge islands into oxide-supported, electrically isolated, Ge-rich nanocrystals. We investigate the process of dewetting and demonstrate that it can be used for the controlled assembly of nanocrystals-from isolated single ones to dense arrays

  7. Apparent de-wetting due to superfluid flow

    CERN Document Server

    Poujade, M; Rolley, E

    2002-01-01

    We have investigated the wetting behaviour of superfluid helium-4 on silicon. Surprisingly, we observe pseudo-de-wetting: though a thick superfluid film covers the substrate, the meniscus displays a finite contact angle which decreases from about 5 deg C at low temperature down to zero at the superfluid transition. We show that this behaviour can be explained by a pressure decrease due to a superfluid flow, closely related to the Kontorovich effect. (authors)

  8. Dewetting of thin polymer film on rough substrate: II. Experiment

    International Nuclear Information System (INIS)

    Volodin, Pylyp; Kondyurin, Alexey

    2008-01-01

    The theory of the dewetting process developed for a model of substrate-film interaction forces was examined by an experimental investigation of the dewetting process of thin polystyrene (PS) films on chemically etched silicon substrates. In the dependence on PS films thickness and silicon roughness, various situations of dewetting were observed as follows: (i) if the wavelength of the substrate roughness is much larger than the critical spinodal wavelength of a film, then spinodal dewetting of the film is observed; (ii) if the wavelength of the substrate roughness is smaller than the critical wavelength of the film and the substrate roughness is larger in comparison with film thickness, then the dewetting due to substrate roughness is observed and the dewetted film patterns repeat the rough substrate structure; (iii) if the wavelength of the substrate roughness is smaller than the critical wavelength of the film and the substrate roughness is small in comparison with the film thickness, then spinodal dewetting proceeds

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

    Science.gov (United States)

    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.

  10. Water-induced ethanol dewetting transition.

    Science.gov (United States)

    Ren, Xiuping; Zhou, Bo; Wang, Chunlei

    2012-07-14

    The dewetting transitions of two hydrophobic plates immersed in pure water, aqueous ethanol solutions with concentrations from 25% to 90%, and pure ethanol were investigated by molecular dynamics simulations, where the dewetting transition was analogous to a first-order phase transition from liquid to vapor. It was found that the dewetting transitions occurred except that in the pure ethanol system. Although the ethanol molecules prefer to locate in the vicinity of the two plates, the inter-plate region is unfavorable for water molecules, due to losing more than one hydrogen bond. Moreover, each inter-plate water molecule forms hydrogen bonds on average with about two ethanol molecules. These intermolecular hydrogen bonds cause water and ethanol to cooperatively fill or exit the inter-plate region. Thus, water molecules play a more important role in the inter-plate filling/empty process, and induce the ethanol dewetting transition. Our results provide insight into the effect of water on the ethanol dewetting phenomena.

  11. The Influence of Cross-Sectional Shape and Orientation of Micropillar Surface on Microdroplet Formation by a Dewetting Process

    Directory of Open Access Journals (Sweden)

    Bambang Arip Dwiyantoro

    2013-07-01

    Full Text Available In this study the dewetting process on micropillars of three different cross-sectional shapes, i.e. circular, square and triangular, was numerically investigated. The influence of the orientation of the triangular and square micropillars on the dewetting behavior was also studied. The numerical simulations showed that the cross-sectional shapes of the micropillars and their orientation play an important role in determining the flow pattern of the dewetting process, especially the evolution and movement of the meniscus across the micropillar before a microdroplet is formed. The diameter of the microdroplets is mainly determined by the capillary effect, viscous drag and fluid inertia contributed by the peeling rate and the thickness of the water layer above the micropillar. The numerical results also indicate that the hydraulic diameter of the micropillars (Dp is one of the parameters governing the size of the microdroplets formed on the top surface of the micropillars after the dewetting process, while the microdroplet diameter is almost insensitive to the cross-sectional shape and orientation of the micropillars. The dimensionless diameter of the microdroplets (d can then be expressed as a function of a dimensionless group, i.e. the Ohnesorge number (Oh, the capillary number (Ca, the dimensionless liquid thickness (H, and the contact angle (q.

  12. Pattern replication by confined dewetting

    NARCIS (Netherlands)

    Harkema, S.; Schäffer, E.; Morariu, M.D.; Steiner, U

    2003-01-01

    The dewetting of a polymer film in a confined geometry was employed in a pattern-replication process. The instability of dewetting films is pinned by a structured confining surface, thereby replicating its topographic pattern. Depending on the surface energy of the confining surface, two different

  13. Influence of film structure on the dewetting kinetics of thin polymer films in the solvent annealing process.

    Science.gov (United States)

    Zhang, Huanhuan; Xu, Lin; Lai, Yuqing; Shi, Tongfei

    2016-06-28

    On a non-wetting solid substrate, the solvent annealing process of a thin polymer film includes the swelling process and the dewetting process. Owing to difficulties in the in situ analysis of the two processes simultaneously, a quantitative study on the solvent annealing process of thin polymer films on the non-wetting solid substrate is extremely rare. In this paper, we design an experimental method by combining spectroscopic ellipsometry with optical microscopy to achieve the simultaneous in situ study. Using this method, we investigate the influence of the structure of swollen film on its dewetting kinetics during the solvent annealing process. The results show that for a thin PS film with low Mw (Mw = 4.1 kg mol(-1)), acetone molecules can form an ultrathin enriched layer between the PS film and the solid substrate during the swelling process. The presence of the acetone enriched layer accounts for the exponential kinetic behavior in the case of a thin PS film with low Mw. However, the acetone enriched layer is not observed in the case of a thin PS film with high Mw (Mw = 400 kg mol(-1)) and the slippage effect of polymer chains is valid during the dewetting process.

  14. Method of drying passivated micromachines by dewetting from a liquid-based process

    Science.gov (United States)

    Houston, Michael R.; Howe, Roger T.; Maboudian, Roya; Srinivasan, Uthara

    2000-01-01

    A method of fabricating a micromachine includes the step of constructing a low surface energy film on the micromachine. The micromachine is then rinsed with a rinse liquid that has a high surface energy, relative to the low surface energy film, to produce a contact angle of greater than 90.degree. between the low surface energy film and the rinse liquid. This relatively large contact angle causes any rinse liquid on the micromachine to be displaced from the micromachine when the micromachine is removed from the rinse liquid. In other words, the micromachine is dried by dewetting from a liquid-based process. Thus, a separate evaporative drying step is not required, as the micromachine is removed from the liquid-based process in a dry state. The relatively large contact angle also operates to prevent attractive capillary forces between micromachine components, thereby preventing contact and adhesion between adjacent microstructure surfaces. The low surface energy film may be constructed with a fluorinated self-assembled monolayer film. The processing of the invention avoids the use of environmentally harmful, health-hazardous chemicals.

  15. Applications of dewetting in micro and nanotechnology.

    Science.gov (United States)

    Gentili, Denis; Foschi, Giulia; Valle, Francesco; Cavallini, Massimiliano; Biscarini, Fabio

    2012-06-21

    Dewetting is a spontaneous phenomenon where a thin film on a surface ruptures into an ensemble of separated objects, like droplets, stripes, and pillars. Spatial correlations with characteristic distance and object size emerge spontaneously across the whole dewetted area, leading to regular motifs with long-range order. Characteristic length scales depend on film thickness, which is a convenient and robust technological parameter. Dewetting is therefore an attractive paradigm for organizing a material into structures of well-defined micro- or nanometre-size, precisely positioned on a surface, thus avoiding lithographical processes. This tutorial review introduces the reader to the physical-chemical basis of dewetting, shows how the dewetting process can be applied to different functional materials with relevance in technological applications, and highlights the possible strategies to control the length scales of the dewetting process.

  16. Deference and Due Process

    OpenAIRE

    Vermeule, Cornelius Adrian

    2015-01-01

    In the textbooks, procedural due process is a strictly judicial enterprise; although substantive entitlements are created by legislative and executive action, it is for courts to decide independently what process the Constitution requires. The notion that procedural due process might be committed primarily to the discretion of the agencies themselves is almost entirely absent from the academic literature. The facts on the ground are very different. Thanks to converging strands of caselaw ...

  17. Wetting - Dewetting Transitions of Au/Ni Bilayer Films

    Science.gov (United States)

    Cen, Xi

    Thin films deposited at low temperatures are often kinetically constrained and will dewet the underlying substrate when annealed. Solid state dewetting is driven by the minimization of the total free energy of thin film-substrate interface and free surface, and mostly occurs through surface diffusion. Dewetting is a serious concern in microelectronics reliability. However, it can also be utilized for the self-assembly of nanostructures with potentials in storage, catalysis, or transistors. Therefore, a fundamental understanding of the dewetting behavior of thin metal films is critical for improving the thermal stability of microelectronics and controlling the order of self-assembled nanostructures. Mechanisms for dewetting of single layer films have been studied extensively. However little work has been reported on multilayer or alloyed thin films. In the thesis, the solid state dewetting of Au/Ni bilayer films deposited on SiO2/Si substrates was investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and aberration corrected scanning TEM (STEM). Ex-situ SEM and TEM studies were performed with in-situ TEM heating characterization to identify the mechanisms during the dewetting process of Au/Ni bilayer films. The solid state dewetting of Au/Ni bilayer films from SiO2/Si substrates exhibits both homogeneous and localized dewetting of Ni and long-edge retraction for Au under isothermal annealing condition. The top Au layer retracts up to 1 mm from the edge of the substrate wafer to reduce the energetically unfavored Au/Ni interface. In contrast, Ni dewets and agglomerates locally due to its limited diffusivity compared to Au. Film morphology and local chemical composition varies significantly across hundreds of microns along the direction normal to the retracting edge. Besides long range edge receding, localized dewetting shows significant changes in film morphology and chemical distribution. Both Au and Ni shows texturing. Despite

  18. Thermodynamics of (Ga, In)-Sb-O-Si and impact on dewetting process

    Energy Technology Data Exchange (ETDEWEB)

    Sylla, L. [Cyberstar, Echirolles (France); Duffar, T. [SIMaP-EPM, Saint Martin d' Heres (France)

    2011-11-15

    A thermodynamic study is performed for the systems (Ga or In)-Sb-O-Si in order to better understand the difference observed during dewetting experiments of GaSb and InSb in silica ampoules. Results show that the melts can be considered as non reactive toward silica. When the atmosphere is clean ({<=}1 ppm O{sub 2}), no oxide is formed, while, under oxidising atmosphere, oxides exist above the melting point of the antimonide and are known to increase the wetting angle of the melt on the crucible. However the temperature range for oxide stability is smaller in the case of InSb and this may explain why dewetting is easy for GaSb in presence of oxygen, while it is difficult for InSb. (copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  19. Interplay between dewetting and layer inversion in poly(4-vinylpyridine)/polystyrene bilayers.

    Science.gov (United States)

    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.

  20. Solution-Processed Small-Molecule Bulk Heterojunctions: Leakage Currents and the Dewetting Issue for Inverted Solar Cells.

    Science.gov (United States)

    Destouesse, Elodie; Chambon, Sylvain; Courtel, Stéphanie; Hirsch, Lionel; Wantz, Guillaume

    2015-11-11

    In organic photovoltaic (PV) devices based on solution-processed small molecules, we report here that the physicochemical properties of the substrate are critical for achieving high-performances organic solar cells. Three different substrates were tested: ITO coated with PSS, ZnO sol-gel, and ZnO nanoparticles. PV performances are found to be low when the ZnO nanoparticles layer is used. This performance loss is attributed to the formation of many dewetting points in the active layer, because of a relatively high roughness of the ZnO nanoparticles layer, compared to the other layers. We successfully circumvented this phenomenon by adding a small quantity of polystyrene (PS) in the active layer. The introduction of PS improves the quality of film forming and reduces the dark currents of solar cells. Using this method, high-efficiency devices were achieved, even in the case of substrates with higher roughness.

  1. Enhanced Self-Organized Dewetting of Ultrathin Polymer Blend Film for Large-Area Fabrication of SERS Substrate.

    Science.gov (United States)

    Zhang, Huanhuan; Xu, Lin; Xu, Yabo; Huang, Gang; Zhao, Xueyu; Lai, Yuqing; Shi, Tongfei

    2016-12-06

    We study the enhanced dewetting of ultrathin Polystyrene (PS)/Poly (methyl methacrylate) (PMMA) blend films in a mixed solution, and reveal the dewetting can act as a simple and effective method to fabricate large-area surface-enhanced Raman scattering (SERS) substrate. A bilayer structure consisting of under PMMA layer and upper PS layer forms due to vertical phase separation of immiscible PS/PMMA during the spin-coating process. The thicker layer of the bilayer structure dominates the dewetting structures of PS/PMMA blend films. The diameter and diameter distribution of droplets, and the average separation spacing between the droplets can be precisely controlled via the change of blend ratio and film thickness. The dewetting structure of 8 nm PS/PMMA (1:1 wt%) blend film is proved to successfully fabricate large-area (3.5 cm × 3.5 cm) universal SERS substrate via deposited a silver layer on the dewetting structure. The SERS substrate shows good SERS-signal reproducibility (RSD dewetting of polymer blend films broadens the application of dewetting of polymer films, especially in the nanotechnology, and may open a new approach for the fabrication of large-area SERS substrate to promote the application of SERS substrate in the rapid sensitive detection of trace molecules.

  2. Perfluoropolyether-Impregnated Mesoporous Alumina Composites Overcome the Dewetting-Tribological Properties Trade-Off.

    Science.gov (United States)

    Rowthu, Sriharitha; Hoffmann, Patrik

    2018-03-28

    Conventional omniphobic surfaces suffer from wear-sensitivity due to soft apolar coatings or substrates and protruding surface features that are eroded even for mild abrasion treatments, leading to the loss of dewetting properties after wear. Evidently, there was a trade-off between dewetting and tribological properties. Here, we show the establishment of self-healing slippery properties post severe abrasion by utilizing perfluoropolyether-impregnated mesoporous Al 2 O 3 (MPA) composites. The hard polar alumina matrix provides the optimal tribological properties, and the liquid lubricant in the porous network contributes to both tribological and self-healing dewetting properties. These composites sustained normal pressures up to 350 MPa during reciprocating sliding contacts. The severely abraded surfaces are capable of self-replenishing in ambient environment, driven by capillarity and surface diffusion processes, and regained their slippery properties toward water and hexadecane after 15 h of self-healing. Eventually, a dewetting-tribology diagram has been introduced to show different regimes, namely-optimal slippery properties, optimal tribological properties, and a mixed regime). We found out that the microstructural expression [Formula: see text] is a robust guiding tool to predict the regime of interest. This dewetting-tribological diagram may be marked as an inception to designing abrasion-resistant slippery liquid impregnated composites for overcoming the dewetting tribological properties trade-off. Such surfaces may potentially find applications in paint industries and as anti-icing surfaces.

  3. Nanoscale View of Dewetting and Coating on Partially Wetted Solids.

    Science.gov (United States)

    Deng, Yajun; Chen, Lei; Liu, Qiao; Yu, Jiapeng; Wang, Hao

    2016-05-19

    There remain significant gaps in our ability to predict dewetting and wetting despite the extensive study over the past century. An important reason is the absence of nanoscopic knowledge about the processes near the moving contact line. This experimental study for the first time obtained the liquid morphology within 10 nm of the contact line, which was receding at low speed (U dewetting far from a simple reverse of wetting. A complete scenario for dewetting and coating is provided.

  4. Dewetting behavior of Au films on porous substrates

    International Nuclear Information System (INIS)

    Zhao Xiaowei; Lee, Ung-Ju; Lee, Kun-Hong

    2010-01-01

    Understanding the stability of thin films and their spontaneous pattern formation upon dewetting is essential to a host of physical phenomena. In this paper, we study the dewetting phenomena of Au thin films deposited on anodic aluminum oxide (AAO) membranes to analyze the stability of the metal film on porous substrates. AAO membranes, as-sputtered and dewetted Au films are all characterized by scanning electronic microscopy and X-ray diffraction. We found that both the roughness of AAO surface and modification of AAO pores exhibit remarkable influences on the dewetting behavior of Au films. The observed dewetting phenomena are explained from an energetic point of view since dewetting is a process of minimization of the system free energy.

  5. Molecular insight into nanoscale water films dewetting on modified silica surfaces.

    Science.gov (United States)

    Zhang, Jun; Li, Wen; Yan, Youguo; Wang, Yefei; Liu, Bing; Shen, Yue; Chen, Haixiang; Liu, Liang

    2015-01-07

    In this work, molecular dynamics simulations are adopted to investigate the microscopic dewetting mechanism of nanoscale water films on methylated silica surfaces. The simulation results show that the dewetting process is divided into two stages: the appearance of dry patches and the quick contraction of the water film. First, the appearance of dry patches is due to the fluctuation in the film thickness originating from capillary wave instability. Second, for the fast contraction of water film, the unsaturated electrostatic and hydrogen bond interactions among water molecules are the driving forces, which induce the quick contraction of the water film. Finally, the effect of film thickness on water films dewetting is studied. Research results suggest that upon increasing the water film thickness from 6 to 8 Å, the final dewetting patterns experience separate droplets and striation-shaped structures, respectively. But upon further increasing the water film thickness, the water film is stable and there are no dry patches. The microscopic dewetting behaviors of water films on methylated silica surfaces discussed here are helpful in understanding many phenomena in scientific and industrial processes better.

  6. Molecular dewetting on insulators

    International Nuclear Information System (INIS)

    Burke, S A; Topple, J M; Gruetter, P

    2009-01-01

    Recent attention given to the growth and morphology of organic thin films with regard to organic electronics has led to the observation of dewetting (a transition from layer(s) to islands) of molecular deposits in many of these systems. Dewetting is a much studied phenomenon in the formation of polymer and liquid films, but its observation in thin films of the 'small' molecules typical of organic electronics requires additional consideration of the structure of the interface between the molecular film and the substrate. This review covers some key concepts related to dewetting and molecular film growth. In particular, the origins of different growth modes and the thickness dependent interactions which give rise to dewetting are discussed in terms of surface energies and the disjoining pressure. Characteristics of molecular systems which may lead to these conditions, including the formation of metastable interface structures and commensurate-incommensurate phase transitions, are also discussed. Brief descriptions of some experimental techniques which have been used to study molecular dewetting are given as well. Examples of molecule-on-insulator systems which undergo dewetting are described in some detail, specifically perylene derivatives on alkali halides, C 60 on alkali halides, and the technologically important system of pentacene on SiO 2 . These examples point to some possible predicting factors for the occurrence of dewetting, most importantly the formation of an interface layer which differs from the bulk crystal structure. (topical review)

  7. Molecular dewetting on insulators.

    Science.gov (United States)

    Burke, S A; Topple, J M; Grütter, P

    2009-10-21

    Recent attention given to the growth and morphology of organic thin films with regard to organic electronics has led to the observation of dewetting (a transition from layer(s) to islands) of molecular deposits in many of these systems. Dewetting is a much studied phenomenon in the formation of polymer and liquid films, but its observation in thin films of the 'small' molecules typical of organic electronics requires additional consideration of the structure of the interface between the molecular film and the substrate. This review covers some key concepts related to dewetting and molecular film growth. In particular, the origins of different growth modes and the thickness dependent interactions which give rise to dewetting are discussed in terms of surface energies and the disjoining pressure. Characteristics of molecular systems which may lead to these conditions, including the formation of metastable interface structures and commensurate-incommensurate phase transitions, are also discussed. Brief descriptions of some experimental techniques which have been used to study molecular dewetting are given as well. Examples of molecule-on-insulator systems which undergo dewetting are described in some detail, specifically perylene derivatives on alkali halides, C(60) on alkali halides, and the technologically important system of pentacene on SiO(2). These examples point to some possible predicting factors for the occurrence of dewetting, most importantly the formation of an interface layer which differs from the bulk crystal structure.

  8. Preventing Thin Film Dewetting via Graphene Capping.

    Science.gov (United States)

    Cao, Peigen; Bai, Peter; Omrani, Arash A; Xiao, Yihan; Meaker, Kacey L; Tsai, Hsin-Zon; Yan, Aiming; Jung, Han Sae; Khajeh, Ramin; Rodgers, Griffin F; Kim, Youngkyou; Aikawa, Andrew S; Kolaczkowski, Mattew A; Liu, Yi; Zettl, Alex; Xu, Ke; Crommie, Michael F; Xu, Ting

    2017-09-01

    A monolayer 2D capping layer with high Young's modulus is shown to be able to effectively suppress the dewetting of underlying thin films of small organic semiconductor molecule, polymer, and polycrystalline metal, respectively. To verify the universality of this capping layer approach, the dewetting experiments are performed for single-layer graphene transferred onto polystyrene (PS), semiconducting thienoazacoronene (EH-TAC), gold, and also MoS 2 on PS. Thermodynamic modeling indicates that the exceptionally high Young's modulus and surface conformity of 2D capping layers such as graphene and MoS 2 substantially suppress surface fluctuations and thus dewetting. As long as the uncovered area is smaller than the fluctuation wavelength of the thin film in a dewetting process via spinodal decomposition, the dewetting should be suppressed. The 2D monolayer-capping approach opens up exciting new possibilities to enhance the thermal stability and expands the processing parameters for thin film materials without significantly altering their physical properties. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. A Dewetting Model for Double-Emulsion Droplets

    Directory of Open Access Journals (Sweden)

    Zhanxiao Kang

    2016-11-01

    Full Text Available The evolution of double-emulsion droplets is of great importance for the application of microdroplets and microparticles. We study the driving force of the dewetting process, the equilibrium configuration and the dewetting time of double-emulsion droplets. Through energy analysis, we find that the equilibrium configuration of a partial engulfed droplet depends on a dimensionless interfacial tension determined by the three relevant interfacial tensions, and the engulfing part of the inner phase becomes larger as the volume of the outer phase increases. By introducing a dewetting boundary, the dewetting time can be calculated by balancing the driving force, caused by interfacial tensions, and the viscous force. Without considering the momentum change of the continuous phase, the dewetting time is an increasing function against the viscosity of the outer phase and the volume ratio between the outer phase and inner phase.

  10. Influence of etching process parameters on the antireflection property of Si SWSs by thermally dewetted Ag and Ag/SiO{sub 2} nanopatterns

    Energy Technology Data Exchange (ETDEWEB)

    Leem, Jung Woo; Yu, Jae Su [Department of Electronics and Radio Engineering, Kyung Hee University, 446-701 Yongin (Korea, Republic of); Song, Young Min; Lee, Yong Tak [Department of Information and Communications, Gwangju Institute of Science and Technology, 500-712 Gwangju (Korea, Republic of)

    2011-08-15

    The etching parameter dependent antireflection characteristics of disordered Si subwavelength structures (SWSs) by inductively coupled plasma (ICP) etching in a mixture gas of SiCl{sub 4}/Ar using thermally dewetted Ag and Ag/SiO{sub 2} nanopatterns are investigated. The average size and period of Si SWSs are closely correlated with thermal dewetting conditions. For desirable Ag nanoparticle patterns, the profile of Si SWSs is optimized by changing the ICP etching process parameters to obtain the lowest reflectance spectrum. The most tapered SWS with the highest height leads to a relatively low reflectance. The Ag nanopatterns result in more tapered and rough surface SWSs compared to the Ag/SiO{sub 2} nanopatterns, indicating a slightly reduced reflectance. The Si SWS etched using Ag nanopatterns by SiCl{sub 4}/Ar of 5 sccm/10 sccm at 50 W RF power, 200 W ICP power, and 10 mTorr process pressure exhibits a very low total reflectance of <{proportional_to}2.4% in the wavelength range of 400-1000 nm, maintaining a specular reflectance of <16% at 350-1100 nm up to the incident angle of {theta}{sub i} = 50 . (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  11. Influence of the substrate on the morphological evolution of gold thin films during solid-state dewetting

    International Nuclear Information System (INIS)

    Nsimama, Patrick D.; Herz, Andreas; Wang, Dong; Schaaf, Peter

    2016-01-01

    Highlights: • Dewetting of thin gold films is faster on TiO_2 than on SiO_2. • Dewetting of thin gold films is faster on amorphous TiO_2 than on crystalline TiO_2. • The kinetics is attributed to the energy of adhesion. • The morphology of thin Au films deposited on TiO_2 substrates is different to those deposited on SiO_2 substrates. • The dewetting activation energy of Au films deposited on crystalline substrates was higher than the activation energy of Au nanofilms deposited on amorphous TiO_2 substrates. - Abstract: The evolution of electron-beam evaporated Au thin films deposited on crystalline TiO_2 (c-TiO_2) and amorphous TiO_2 (a-TiO_2) as well as amorphous SiO_2 substrates are investigated. The kinetic of dewetting is clearly dependent on the type of substrate and is faster on TiO_2 substrates than on SiO_2 substrates. This difference can result from the difference in adhesion energy. Furthermore, the kinetic of dewetting is faster on a-TiO_2 than on c-TiO_2, possibly due to the crystallization of TiO_2 during annealing induced dewetting process. The morphologies of dewetted Au films deposited on crystalline TiO_2 are characterized by branched holes. The XRD patterns of the Au films deposited on TiO_2 substrates constituted peaks from both metallic Au and anatase TiO_2. The activation energy of Au films deposited on crystalline TiO_2 substrates was higher than that that of the films deposited on amorphous TiO_2 substrates.

  12. Influence of the substrate on the morphological evolution of gold thin films during solid-state dewetting

    Energy Technology Data Exchange (ETDEWEB)

    Nsimama, Patrick D. [TU Ilmenau, Institute of Materials Engineering and Institute of Micro- and Nanotechnologies MacroNano, Chair Materials for Electrical Engineering and Electronics, 98693 Ilmenau (Germany); Dar Es Salaam Institute of Technology, P.O. Box 2958, Dar Es Salaam (Tanzania, United Republic of); Herz, Andreas; Wang, Dong [TU Ilmenau, Institute of Materials Engineering and Institute of Micro- and Nanotechnologies MacroNano, Chair Materials for Electrical Engineering and Electronics, 98693 Ilmenau (Germany); Schaaf, Peter, E-mail: peter.schaaf@tu-ilmenau.de [TU Ilmenau, Institute of Materials Engineering and Institute of Micro- and Nanotechnologies MacroNano, Chair Materials for Electrical Engineering and Electronics, 98693 Ilmenau (Germany)

    2016-12-01

    Highlights: • Dewetting of thin gold films is faster on TiO{sub 2} than on SiO{sub 2}. • Dewetting of thin gold films is faster on amorphous TiO{sub 2} than on crystalline TiO{sub 2}. • The kinetics is attributed to the energy of adhesion. • The morphology of thin Au films deposited on TiO{sub 2} substrates is different to those deposited on SiO{sub 2} substrates. • The dewetting activation energy of Au films deposited on crystalline substrates was higher than the activation energy of Au nanofilms deposited on amorphous TiO{sub 2} substrates. - Abstract: The evolution of electron-beam evaporated Au thin films deposited on crystalline TiO{sub 2} (c-TiO{sub 2}) and amorphous TiO{sub 2} (a-TiO{sub 2}) as well as amorphous SiO{sub 2} substrates are investigated. The kinetic of dewetting is clearly dependent on the type of substrate and is faster on TiO{sub 2} substrates than on SiO{sub 2} substrates. This difference can result from the difference in adhesion energy. Furthermore, the kinetic of dewetting is faster on a-TiO{sub 2} than on c-TiO{sub 2}, possibly due to the crystallization of TiO{sub 2} during annealing induced dewetting process. The morphologies of dewetted Au films deposited on crystalline TiO{sub 2} are characterized by branched holes. The XRD patterns of the Au films deposited on TiO{sub 2} substrates constituted peaks from both metallic Au and anatase TiO{sub 2}. The activation energy of Au films deposited on crystalline TiO{sub 2} substrates was higher than that that of the films deposited on amorphous TiO{sub 2} substrates.

  13. Teacher Dismissal and Due Process.

    Science.gov (United States)

    Leichner, Edward C.; Blackstone, Sidney

    1977-01-01

    This article addresses due process requirements in the nonrenewal and dismissal of tenured and nontenured teachers. The Georgia Fair Dismissal Law is used as a basis for discussing the grounds for teacher dismissal. Dismissal grounds discussed are 1) incompetency; 2) insubordination; 3) willful neglect of duties; 4) immorality; 5) inciting,…

  14. Due Process Hearing Case Study

    Science.gov (United States)

    Bateman, David F.

    2009-01-01

    William is 9 years of age, residing with his parent within the boundaries of an unnamed district ("the District"). As a student with autism he is eligible for special education programming and services. There was one issue presented for this due process hearing: What was the appropriate program and placement for him for the 2008-2009 school year?…

  15. Time-resolved analysis of thickness-dependent dewetting and ablation of silver films upon nanosecond laser irradiation

    International Nuclear Information System (INIS)

    Qi, Dongfeng; Paeng, Dongwoo; Yeo, Junyeob; Kim, Eunpa; Wang, Letian; Grigoropoulos, Costas P.; Chen, Songyan

    2016-01-01

    Nanosecond pulsed laser dewetting and ablation of thin silver films is investigated by time-resolved imaging. Laser pulses of 532 nm wavelength and 5 ns temporal width are irradiated on silver films of different thicknesses (50 nm, 80 nm, and 350 nm). Below the ablation threshold, it is observed that the dewetting process does not conclude until 630 ns after the laser irradiation for all samples, forming droplet-like particles in the spot central region. At higher laser intensities, ablative material removal occurs in the spot center. Cylindrical rims are formed in the peripheral dewetting zone due to the solidification of transported matter at about 700 ns following the laser pulse exposure. In addition to these features, droplet fingers are superposed upon irradiation of 350-nm thick silver films with higher intensity.

  16. Time-resolved analysis of thickness-dependent dewetting and ablation of silver films upon nanosecond laser irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Qi, Dongfeng [Laser Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, California 94720-1740 (United States); Semiconductor Photonics Research Center, Department of Physics, Xiamen University, Xiamen 361005 (China); Paeng, Dongwoo; Yeo, Junyeob; Kim, Eunpa; Wang, Letian; Grigoropoulos, Costas P., E-mail: cgrigoro@berkeley.edu [Laser Thermal Laboratory, Department of Mechanical Engineering, University of California, Berkeley, California 94720-1740 (United States); Chen, Songyan [Semiconductor Photonics Research Center, Department of Physics, Xiamen University, Xiamen 361005 (China)

    2016-05-23

    Nanosecond pulsed laser dewetting and ablation of thin silver films is investigated by time-resolved imaging. Laser pulses of 532 nm wavelength and 5 ns temporal width are irradiated on silver films of different thicknesses (50 nm, 80 nm, and 350 nm). Below the ablation threshold, it is observed that the dewetting process does not conclude until 630 ns after the laser irradiation for all samples, forming droplet-like particles in the spot central region. At higher laser intensities, ablative material removal occurs in the spot center. Cylindrical rims are formed in the peripheral dewetting zone due to the solidification of transported matter at about 700 ns following the laser pulse exposure. In addition to these features, droplet fingers are superposed upon irradiation of 350-nm thick silver films with higher intensity.

  17. Spontaneous dewetting of a perfluoropolyether

    Science.gov (United States)

    Shogrin, Bradley; Jones, William R., Jr.; Herrera-Fierro, Pilar

    1995-01-01

    Eight different production lots of a commercial perfluoropolyether (PFPE) based on hexafluoropropene oxide (HFPO) were applied to polished metal surfaces by spinning. One of the lots repeatedly dewetted from a clean 440C steel surface, forming droplets on the surface, whereas the other seven did not dewet. This dewetting phenomenon also repeatedly occurred on 2024 aluminum and 1018 steel, but not on copper or gold. Fourier transform infrared microspectroscopy (mu-FTIR) was used to determine thickness and uniformity of the PFPE films. The dewetting lot was found to dewet from 440C steel at a film thickness greater than 520 A. A portion of the dewetting lot was heated at 316 C for 12 days in the presence of oxygen and M-50 steel. This fluid did not dewet. Sequentially, samples of the dewetting lot were filtered either with an alumina or a silica cartridge which can remove polar impurities. Neither of the filtered samples dewetted from 440C steel. It was concluded that an unknown impurity, both thermally labile and polar, present at very low concentration and undetected by our analytical techniques (FTIR, proton NMR, or F-19 NMR), was responsible for the dewetting phenomenon.

  18. Domain growth of carbon nanotubes assisted by dewetting of thin catalyst precursor films

    Energy Technology Data Exchange (ETDEWEB)

    Srivastava, Alok Kumar [Defence Materials and Stores R and D Establishment (DRDO), GT Road, Kanpur 208013 (India); Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016 (India); Sachan, Priyanka; Samanta, Chandan [Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016 (India); Mukhopadhyay, Kingsuk [Defence Materials and Stores R and D Establishment (DRDO), GT Road, Kanpur 208013 (India); Sharma, Ashutosh, E-mail: ashutos@iitk.ac.in [Department of Chemical Engineering, Indian Institute of Technology, Kanpur 208016 (India)

    2014-01-01

    We explore self-organized dewetting of ultrathin films of a novel metal complex as a one step surface patterning method to create nanoislands of iron, using which spatially separated carbon nanostructures were synthesized. Dewetting of ultrathin metal complex films was induced by two different methods: liquid solvent exposure and thermal annealing to engender surface patterning. For thermal dewetting, thin films of the iron oleate complex were dewetted at high temperature. In the case of liquid solvent assisted dewetting, the metal complex, mixed with a sacrificial polymer (polystyrene) was spin coated as thin films (<40 nm) and then dewetted under an optimal solution mixture consisting of methyl ethyl ketone, acetone and water. The carrier polymer was then selectively removed to produce the iron metal islands. These metal islands were used for selective growth of discrete patches of multiwall CNTs and CNFs by a chemical vapor deposition (CVD) process. Solvent induced dewetting showed clear advantages over thermal dewetting owing to reduced size of catalyst domains formed by dewetting, an improved control over CNT growth as well as in its ability to immobilize the seed particles. The generic solution mediated dewetting and pattern generation in thin films of various catalytic precursors can thus be a powerful method for selective domain growth of a variety of functional nanomaterials.

  19. Mechanism of solid-state plasma-induced dewetting for formation of copper and gold nanoparticles.

    Science.gov (United States)

    Kwon, Soon-Ho; Choe, Han Joo; Lee, Hyo-Chang; Chung, Chin-Wook; Lee, Jung-Joong

    2013-09-01

    Cu and Au nanoparticles were fabricated by plasma treatment on Cu and Au films at 653 K. The nanoparticles were formed by dewetting the metallic films using plasma. Scanning electron microscopy and transmission electron microscopy investigations showed that the plasma-induced dewetting of the Cu and Au films proceeded through heterogeneous hole nucleation and growth along the grain boundaries to lower the surface energy. The amount of energy transferred to surface atoms by one Ar ion was calculated to be 16.1 eV, which was sufficient for displacing Cu and Au atoms. Compared to thermally activated dewetting, more uniform particles could be obtained by plasma-induced dewetting because a much larger number of holes with smaller sizes was generated. The plasma dewetting process is less sensitive to the oxidation of metallic films compared to the annealing process. As a result, Cu nanoparticles could be fabricated at 653 K, whereas the thermally activated dewetting was not possible.

  20. The influence of polymer architectures on the dewetting behavior of thin polymer films: from linear chains to ring chains.

    Science.gov (United States)

    Wang, Lina; Xu, Lin; Liu, Binyuan; Shi, Tongfei; Jiang, Shichun; An, Lijia

    2017-05-03

    The dewetting behavior of ring polystyrene (RPS) film and linear polystyrene (LPS) film on silanized Si substrates with different grafting densities and PDMS substrate was investigated. Results showed that polymer architectures greatly influenced the dewetting behavior of the thin polymer film. On the silanized Si substrate with 69% grafting density, RPS chains exhibited stronger adsorption compared with LPS chains, and as a result the wetting layer formed more easily. For LPS films, with a decreased annealing temperature, the stability of the polymer film changed from non-slip dewetting via apparent slip dewetting to apparently stable. However, for RPS films, the polymer film stability switched from apparent slip dewetting to apparently stable. On the silanized Si substrate with 94% grafting density, the chain adsorption became weaker and the dewetting processes were faster than that on the substrate with 69% grafting density at the same experimental temperature for both the LPS and RPS films. Moreover, on the PDMS substrate, LPS films always showed non-slip dewetting, while the dewetting kinetics of RPS films switched from non-slip dewetting to slip dewetting behaviour. Forming the wetting layer strongly influenced the stability and dewetting behavior of the thin polymer films.

  1. The kinetics of dewetting ultra-thin Si layers from silicon dioxide

    International Nuclear Information System (INIS)

    Aouassa, M; Favre, L; Ronda, A; Berbezier, I; Maaref, H

    2012-01-01

    In this study, we investigate the kinetically driven dewetting of ultra-thin silicon films on silicon oxide substrate under ultra-high vacuum, at temperatures where oxide desorption and silicon lost could be ruled out. We show that in ultra-clean experimental conditions, the three different regimes of dewetting, namely (i) nucleation of holes, (ii) film retraction and (iii) coalescence of holes, can be quantitatively measured as a function of temperature, time and thickness. For a nominal flat clean sample these three regimes co-exist during the film retraction until complete dewetting. To discriminate their roles in the kinetics of dewetting, we have compared the dewetting evolution of flat unpatterned crystalline silicon layers (homogeneous dewetting), patterned crystalline silicon layers (heterogeneous dewetting) and amorphous silicon layers (crystallization-induced dewetting). The first regime (nucleation) is described by a breaking time which follows an exponential evolution with temperature with an activation energy E H ∼ 3.2 eV. The second regime (retraction) is controlled by surface diffusion of matter from the edges of the holes. It involves a very fast redistribution of matter onto the flat Si layer, which prevents the formation of a rim on the edges of the holes during both heterogeneous and homogeneous dewetting. The time evolution of the linear dewetting front measured during heterogeneous dewetting follows a characteristic power law x ∼ t 0.45 consistent with a surface diffusion-limited mechanism. It also evolves as x ∼ h -1 as expected from mass conservation in the absence of thickened rim. When the surface energy is isotropic (during dewetting of amorphous Si) the dynamics of dewetting is considerably modified: firstly, there is no measurable breaking time; secondly, the speed of dewetting is two orders of magnitude larger than for crystalline Si; and thirdly, the activation energy of dewetting is much smaller due to the different driving

  2. Surface phase separation, dewetting feature size, and crystal morphology in thin films of polystyrene/poly(ε-caprolactone) blend.

    Science.gov (United States)

    Ma, Meng; He, Zhoukun; Li, Yuhan; Chen, Feng; Wang, Ke; Zhang, Qing; Deng, Hua; Fu, Qiang

    2012-12-01

    Thin films of polystyrene (PS)/poly(ε-caprolactone) (PCL) blends were prepared by spin-coating and characterized by tapping mode force microscopy (AFM). Effects of the relative concentration of PS in polymer solution on the surface phase separation and dewetting feature size of the blend films were systematically studied. Due to the coupling of phase separation, dewetting, and crystallization of the blend films with the evaporation of solvent during spin-coating, different size of PS islands decorated with various PCL crystal structures including spherulite-like, flat-on individual lamellae, and flat-on dendritic crystal were obtained in the blend films by changing the film composition. The average distance of PS islands was shown to increase with the relative concentration of PS in casting solution. For a given ratio of PS/PCL, the feature size of PS appeared to increase linearly with the square of PS concentration while the PCL concentration only determined the crystal morphology of the blend films with no influence on the upper PS domain features. This is explained in terms of vertical phase separation and spinodal dewetting of the PS rich layer from the underlying PCL rich layer, leading to the upper PS dewetting process and the underlying PCL crystalline process to be mutually independent. Copyright © 2012 Elsevier Inc. All rights reserved.

  3. Anisotropic dewetting of ion irradiated solid films

    Energy Technology Data Exchange (ETDEWEB)

    Repetto, L., E-mail: luca.repetto@unige.it [Dipartimento di fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Šetina Batič, B. [Inštitut Za Kovinske Materiale in Tehnologije, Lepi pot 11, 1000 Ljubljana (Slovenia); Firpo, G.; Piano, E.; Valbusa, U. [Dipartimento di fisica, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy)

    2013-11-15

    Experiments of irradiation with 30 keV Ga ions were conducted on ultrathin chromium films on rippled silicon substrates. The evolution of their surface morphology, as detected by real time scanning electron microscopy, shows an apparent differential sputtering yield for regions of positive and negative curvature which is in contrast with the standard theory for curvature depending sputtering yield. In particular, at the end of the irradiation process, chromium wires are left in the valleys of the substrate. This result was explained in terms of local melting caused by the ion impact and of a process of dewetting under the concurring actions of surface tension and Van der Waals forces while ion sputtering is active. The interpretation of the reported experimental results are fully supported by numeric simulations implementing the same continuum model used to explain ion induced spinodal dewetting. This hierarchical self-organization process breaks the symmetry of previously demonstrated ion induced dewetting, making possible to create new structures by using the same fundamental effects.

  4. 5 CFR 732.301 - Due process.

    Science.gov (United States)

    2010-01-01

    ... 5 Administrative Personnel 2 2010-01-01 2010-01-01 false Due process. 732.301 Section 732.301...) NATIONAL SECURITY POSITIONS Due Process and Reporting § 732.301 Due process. When an agency makes an... any determination. (b) Comply with all applicable administrative due process requirements, as provided...

  5. Correlated dewetting patterns in thin polystyrene films

    CERN Document Server

    Neto, C; Seemann, R; Blossey, R; Becker, J; Grün, G

    2003-01-01

    We describe preliminary results of experiments and simulations concerned with the dewetting of thin polystyrene films (thickness < 7 nm) on top of silicon oxide wafers. In the experiments we scratched an initially flat film with an atomic force microscopy (AFM) tip, producing dry channels in the film. Dewetting of the films was imaged in situ using AFM and a correlated pattern of holes ('satellite holes') was observed along the rims bordering the channels. The development of this complex film rupture process was simulated and the results of experiments and simulations are in good agreement. On the basis of these results, we attempt to explain the appearance of satellite holes and their positions relative to pre-existing holes.

  6. Correlated dewetting patterns in thin polystyrene films

    International Nuclear Information System (INIS)

    Neto, Chiara; Jacobs, Karin; Seemann, Ralf; Blossey, Ralf; Becker, Juergen; Gruen, Guenther

    2003-01-01

    We describe preliminary results of experiments and simulations concerned with the dewetting of thin polystyrene films (thickness < 7 nm) on top of silicon oxide wafers. In the experiments we scratched an initially flat film with an atomic force microscopy (AFM) tip, producing dry channels in the film. Dewetting of the films was imaged in situ using AFM and a correlated pattern of holes ('satellite holes') was observed along the rims bordering the channels. The development of this complex film rupture process was simulated and the results of experiments and simulations are in good agreement. On the basis of these results, we attempt to explain the appearance of satellite holes and their positions relative to pre-existing holes

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

    Science.gov (United States)

    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.

  8. Kinetics of sub-spinodal dewetting of thin films of thickness dependent viscosity.

    Science.gov (United States)

    Kotni, Tirumala Rao; Khanna, Rajesh; Sarkar, Jayati

    2017-05-04

    An alternative explanation of the time varying and very low growth exponents in dewetting of polymer films like polystyrene films is presented based on non-linear simulations. The kinetics of these films is explored within the framework of experimentally observed thickness dependent viscosity. These films exhibit sub-spinodal dewetting via formation of satellite holes in between primary dewetted holes under favorable conditions of excess intermolecular forces and film thicknesses. We find that conditions responsible for sub-spinodal dewetting concurrently lead to remarkable changes in the kinetics of dewetting of even primary holes. For example, the radius of the hole grows in time with a power-law growth exponent sequence of [Formula: see text], in contrast to the usual  ∼4/5. This is due to the cumulative effect of reduced rim mobility due to thickness dependent viscosity and hindrance created by satellite holes.

  9. Spatial control of direct chemical vapor deposition of graphene on silicon dioxide by directional copper dewetting

    NARCIS (Netherlands)

    van den Beld, Wesley Theodorus Eduardus; van den Berg, Albert; Eijkel, Jan C.T.

    2016-01-01

    In this paper we present a method for the spatial control of direct graphene synthesis onto silicon dioxide by controlled dewetting. The dewetting process is controlled through a combination of using a grooved substrate and conducting copper deposition at an angle. The substrate is then treated

  10. Solid-state dewetting of Au/Ni bilayers: The effect of alloying on morphology evolution

    International Nuclear Information System (INIS)

    Herz, A.; Wang, D.; Kups, Th.; Schaaf, P.

    2014-01-01

    The solid-state dewetting of thin Au/Ni bilayers deposited onto SiO 2 /Si substrates is investigated. A rapid thermal treatment is used to induce the dewetting process by an increase in temperature. The evolution of the (111) peaks of X-ray diffraction reveals a characteristic change due to mixing of Au and Ni. At low temperature, the Au-Ni thin film is found to break up at the phase boundaries and growing voids are shown to be surrounded by a Ni-rich phase. Branch-like void growth is observed. Upon annealing at increasing temperatures, Au-Ni solid solutions are formed well above the bulk equilibrium solubility of Au and Ni. It is found that this metastable phase formation makes the Au-Ni thin film less vulnerable to rupturing. Moreover, growth mode of still evolving voids changes into a more regular, faceted one due to alloying. Finally, it is shown that annealing above the miscibility gap forms supersaturated, well-oriented Au-Ni solid solution agglomerates via dewetting.

  11. Solid-state dewetting of Au/Ni bilayers: The effect of alloying on morphology evolution

    Energy Technology Data Exchange (ETDEWEB)

    Herz, A.; Wang, D., E-mail: dong.wang@tu-ilmenau.de; Kups, Th.; Schaaf, P. [Institute of Materials Engineering and Institute of Micro- and Nanotechnologies MacroNano, Chair Materials for Electronics and Electrical Engineering, TU Ilmenau, Ilmenau 98693 (Germany)

    2014-07-28

    The solid-state dewetting of thin Au/Ni bilayers deposited onto SiO{sub 2}/Si substrates is investigated. A rapid thermal treatment is used to induce the dewetting process by an increase in temperature. The evolution of the (111) peaks of X-ray diffraction reveals a characteristic change due to mixing of Au and Ni. At low temperature, the Au-Ni thin film is found to break up at the phase boundaries and growing voids are shown to be surrounded by a Ni-rich phase. Branch-like void growth is observed. Upon annealing at increasing temperatures, Au-Ni solid solutions are formed well above the bulk equilibrium solubility of Au and Ni. It is found that this metastable phase formation makes the Au-Ni thin film less vulnerable to rupturing. Moreover, growth mode of still evolving voids changes into a more regular, faceted one due to alloying. Finally, it is shown that annealing above the miscibility gap forms supersaturated, well-oriented Au-Ni solid solution agglomerates via dewetting.

  12. Reduction of nanowire diameter beyond lithography limits by controlled catalyst dewetting

    International Nuclear Information System (INIS)

    Calahorra, Yonatan; Kerlich, Alexander; Gavrilov, Arkady; Cohen, Shimon; Ritter, Dan; Amram, Dor

    2016-01-01

    Catalyst assisted vapour-liquid–solid is the most common method to realize bottom-up nanowire growth; establishing a parallel process for obtaining nanoscale catalysts at pre-defined locations is paramount for further advancement towards commercial nanowire applications. Herein, the effect of a selective area mask on the dewetting of metallic nanowire catalysts, deposited within lithography-defined mask pinholes, is reported. It was found that thin disc-like catalysts, with diameters of 120–450 nm, were transformed through dewetting into hemisphere-like catalysts, having diameters 2–3 fold smaller; the process was optimized to about 95% yield in preventing catalyst splitting, as would otherwise be expected due to their thickness-to-diameter ratio, which was as low as 1/60. The catalysts subsequently facilitated InP and InAs nanowire growth. We suggest that the mask edges prevent surface migration mediated spreading of the dewetted metal, and therefore induce its agglomeration into a single particle. This result presents a general strategy to diminish lithography-set dimensions for NW growth, and may answer a fundamental challenge faced by bottom-up nanowire technology. (paper)

  13. Reduction of nanowire diameter beyond lithography limits by controlled catalyst dewetting

    Science.gov (United States)

    Calahorra, Yonatan; Kerlich, Alexander; Amram, Dor; Gavrilov, Arkady; Cohen, Shimon; Ritter, Dan

    2016-04-01

    Catalyst assisted vapour-liquid-solid is the most common method to realize bottom-up nanowire growth; establishing a parallel process for obtaining nanoscale catalysts at pre-defined locations is paramount for further advancement towards commercial nanowire applications. Herein, the effect of a selective area mask on the dewetting of metallic nanowire catalysts, deposited within lithography-defined mask pinholes, is reported. It was found that thin disc-like catalysts, with diameters of 120-450 nm, were transformed through dewetting into hemisphere-like catalysts, having diameters 2-3 fold smaller; the process was optimized to about 95% yield in preventing catalyst splitting, as would otherwise be expected due to their thickness-to-diameter ratio, which was as low as 1/60. The catalysts subsequently facilitated InP and InAs nanowire growth. We suggest that the mask edges prevent surface migration mediated spreading of the dewetted metal, and therefore induce its agglomeration into a single particle. This result presents a general strategy to diminish lithography-set dimensions for NW growth, and may answer a fundamental challenge faced by bottom-up nanowire technology.

  14. Dewetting-mediated pattern formation in nanoparticle assemblies

    International Nuclear Information System (INIS)

    Stannard, Andrew

    2011-01-01

    The deposition of nanoparticles from solution onto solid substrates is a diverse subfield of current nanoscience research. Complex physical and chemical processes underpin the self-assembly and self-organization of colloidal nanoparticles at two-phase (solid-liquid, liquid-air) interfaces and three-phase (solid-liquid-air) contact lines. This review discusses key recent advances made in the understanding of nonequilibrium dewetting processes of nanoparticle-containing solutions, detailing how such an apparently simple experimental system can give rise to such a strikingly varied palette of two-dimensional self-organized nanoparticle array morphologies. Patterns discussed include worm-like domains, cellular networks, microscale rings, and fractal-like fingering structures. There remain many unresolved issues regarding the role of the solvent dewetting dynamics in assembly processes of this type, with a significant focus on how dewetting can be coerced to produce nanoparticle arrays with desirable characteristics such as long-range order. In addition to these topics, methods developed to control nanofluid dewetting through routes such as confining the geometries of drying solutions, depositing onto pre-patterned heterogeneous substrates, and post-dewetting pattern evolution via local or global manipulation are covered. (topical review)

  15. Dewetting-mediated pattern formation in nanoparticle assemblies.

    Science.gov (United States)

    Stannard, Andrew

    2011-03-02

    The deposition of nanoparticles from solution onto solid substrates is a diverse subfield of current nanoscience research. Complex physical and chemical processes underpin the self-assembly and self-organization of colloidal nanoparticles at two-phase (solid-liquid, liquid-air) interfaces and three-phase (solid-liquid-air) contact lines. This review discusses key recent advances made in the understanding of nonequilibrium dewetting processes of nanoparticle-containing solutions, detailing how such an apparently simple experimental system can give rise to such a strikingly varied palette of two-dimensional self-organized nanoparticle array morphologies. Patterns discussed include worm-like domains, cellular networks, microscale rings, and fractal-like fingering structures. There remain many unresolved issues regarding the role of the solvent dewetting dynamics in assembly processes of this type, with a significant focus on how dewetting can be coerced to produce nanoparticle arrays with desirable characteristics such as long-range order. In addition to these topics, methods developed to control nanofluid dewetting through routes such as confining the geometries of drying solutions, depositing onto pre-patterned heterogeneous substrates, and post-dewetting pattern evolution via local or global manipulation are covered.

  16. Role of substrate morphology in ion induced dewetting of thin solid films

    Energy Technology Data Exchange (ETDEWEB)

    Repetto, Luca, E-mail: luca.repetto@unige.it [Physics Department and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Lo Savio, Roberto [Physics Department and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Šetina Batič, Barbara [Inštitut Za Kovinske Materiale in Tehnologije, Lepi pot 11, 1000 Ljubljana (Slovenia); Firpo, Giuseppe; Valbusa, Ugo [Physics Department and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy)

    2014-10-01

    Highlights: • We have created by ion bombardment silicon substrates with different topographies. • The substrates have been characterized by ellipsometry, AFM, SEM and EDX. • The substrates have been used for experiments of ion induced Cr films. • We show that different substrate topographies can induce different dewetted patterns. • Substrate topography can favor spinodal dewetting against heterogeneous nucleations. - Abstract: We investigate the role of the substrate morphology in the dewetting of ultrathin chromium films irradiated with 30 keV Ga ions. Silicon surfaces with different roughness were used as substrates for the films. The results of the irradiation experiments and of related simulations indicate that the chromium films can undergo a dewetting-like process through the two standard channels that show up for liquids, namely the spinodal channel, and the dewetting by heterogeneous nucleation. The two processes are competitive, and the prevailing one can be predicted and selected according to the characteristics of the substrate.

  17. Role of substrate morphology in ion induced dewetting of thin solid films

    International Nuclear Information System (INIS)

    Repetto, Luca; Lo Savio, Roberto; Šetina Batič, Barbara; Firpo, Giuseppe; Valbusa, Ugo

    2014-01-01

    Highlights: • We have created by ion bombardment silicon substrates with different topographies. • The substrates have been characterized by ellipsometry, AFM, SEM and EDX. • The substrates have been used for experiments of ion induced Cr films. • We show that different substrate topographies can induce different dewetted patterns. • Substrate topography can favor spinodal dewetting against heterogeneous nucleations. - Abstract: We investigate the role of the substrate morphology in the dewetting of ultrathin chromium films irradiated with 30 keV Ga ions. Silicon surfaces with different roughness were used as substrates for the films. The results of the irradiation experiments and of related simulations indicate that the chromium films can undergo a dewetting-like process through the two standard channels that show up for liquids, namely the spinodal channel, and the dewetting by heterogeneous nucleation. The two processes are competitive, and the prevailing one can be predicted and selected according to the characteristics of the substrate

  18. Not spreading in reverse: The dewetting of a liquid film into a single drop.

    Science.gov (United States)

    Edwards, Andrew M J; Ledesma-Aguilar, Rodrigo; Newton, Michael I; Brown, Carl V; McHale, Glen

    2016-09-01

    Wetting and dewetting are both fundamental modes of motion of liquids on solid surfaces. They are critically important for processes in biology, chemistry, and engineering, such as drying, coating, and lubrication. However, recent progress in wetting, which has led to new fields such as superhydrophobicity and liquid marbles, has not been matched by dewetting. A significant problem has been the inability to study the model system of a uniform film dewetting from a nonwetting surface to a single macroscopic droplet-a barrier that does not exist for the reverse wetting process of a droplet spreading into a film. We report the dewetting of a dielectrophoresis-induced film into a single equilibrium droplet. The emergent picture of the full dewetting dynamics is of an initial regime, where a liquid rim recedes at constant speed and constant dynamic contact angle, followed by a relatively short exponential relaxation of a spherical cap shape. This sharply contrasts with the reverse wetting process, where a spreading droplet follows a smooth sequence of spherical cap shapes. Complementary numerical simulations and a hydrodynamic model reveal a local dewetting mechanism driven by the equilibrium contact angle, where contact line slip dominates the dewetting dynamics. Our conclusions can be used to understand a wide variety of processes involving liquid dewetting, such as drop rebound, condensation, and evaporation. In overcoming the barrier to studying single film-to-droplet dewetting, our results provide new approaches to fluid manipulation and uses of dewetting, such as inducing films of prescribed initial shapes and slip-controlled liquid retraction.

  19. Retardation the dewetting dynamics of ultrathin polystyrene films using highly branched aromatic molecules as additives

    International Nuclear Information System (INIS)

    Pangpaiboon, Nampueng; Traiphol, Nisanart; Promarak, Vinich; Traiphol, Rakchart

    2013-01-01

    This study introduces a new class of materials as a dewetting inhibitor for polystyrene (PS) ultrathin films. Two types of highly branched aromatic (HBA) molecules are added into PS films with thicknesses of 7 nm and 23 nm. Their concentrations range from 0.75 to 5 wt.%. The films are annealed in vacuum oven at elevated temperatures to accelerate dewetting process. Evolution of the film morphologies is followed by utilizing atomic force microscopy and optical microscopy. Contact angle measurements are used to evaluate interfacial interactions in each system. Dewetting area as a function of annealing time and HBA concentration are calculated. We have found that the presence of only 0.5 wt.% HBA can suppress the dewetting dynamics of PS films. Increasing the HBA concentration from 0.5 to 5 wt.% causes systematic decrease of the dewetting rate. In this system, the HBA molecules behave as physical cross-linking points for PS chains, which lead to the improvement of film stability. The efficiency of HBA as a dewetting inhibitor varies with molecular weight of PS while the change of HBA structure hardly affects the dewetting behaviors. - Highlights: • New method for improving stability of polystyrene (PS) thin films • Highly branched aromatic molecules (HBA) are used to suppress the dewetting. • Thermal stability of blended PS/HBA films greatly improves. • The effectiveness of HBA varies with molecular weight of PS. • Important results for designing materials in coating application

  20. Retardation the dewetting dynamics of ultrathin polystyrene films using highly branched aromatic molecules as additives

    Energy Technology Data Exchange (ETDEWEB)

    Pangpaiboon, Nampueng [Research Unit of Advanced Ceramics, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Traiphol, Nisanart, E-mail: Nisanart.T@chula.ac.th [Research Unit of Advanced Ceramics, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Promarak, Vinich [School of Chemistry and Center of Excellence for Innovation in Chemistry, Institute of Science, Suranaree University of Technology, Nakhon Ratchasima 30000 (Thailand); Traiphol, Rakchart, E-mail: Rakchartt@nu.ac.th [Laboratory of Advanced Polymers and Nanomaterials, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Naresuan University, Phitsanulok 65000 (Thailand); NANOTEC-MU Excellence Center on Intelligent Materials and Systems, Faculty of Science, Rama 6 Road, Ratchathewi, Bangkok 10400 (Thailand)

    2013-12-02

    This study introduces a new class of materials as a dewetting inhibitor for polystyrene (PS) ultrathin films. Two types of highly branched aromatic (HBA) molecules are added into PS films with thicknesses of 7 nm and 23 nm. Their concentrations range from 0.75 to 5 wt.%. The films are annealed in vacuum oven at elevated temperatures to accelerate dewetting process. Evolution of the film morphologies is followed by utilizing atomic force microscopy and optical microscopy. Contact angle measurements are used to evaluate interfacial interactions in each system. Dewetting area as a function of annealing time and HBA concentration are calculated. We have found that the presence of only 0.5 wt.% HBA can suppress the dewetting dynamics of PS films. Increasing the HBA concentration from 0.5 to 5 wt.% causes systematic decrease of the dewetting rate. In this system, the HBA molecules behave as physical cross-linking points for PS chains, which lead to the improvement of film stability. The efficiency of HBA as a dewetting inhibitor varies with molecular weight of PS while the change of HBA structure hardly affects the dewetting behaviors. - Highlights: • New method for improving stability of polystyrene (PS) thin films • Highly branched aromatic molecules (HBA) are used to suppress the dewetting. • Thermal stability of blended PS/HBA films greatly improves. • The effectiveness of HBA varies with molecular weight of PS. • Important results for designing materials in coating application.

  1. Satellite hole formation during dewetting: experiment and simulation

    International Nuclear Information System (INIS)

    Neto, Chiara; Jacobs, Karin; Seemann, Ralf; Blossey, Ralf; Becker, Juergen; Gruen, Guenther

    2003-01-01

    The dewetting of thin polymer films on solid substrates has been studied extensively in recent years. These films can decay either by nucleation events or by spinodal dewetting, essentially only depending on the interface potential describing the short- and long-range intermolecular interactions between the interfaces and the initial film thickness. Here, we describe experiments and simulations concerned with the decay of polystyrene thin films. The rupture of the film occurs by the formation of a correlated pattern of holes ('satellite holes') along the liquid rims accumulating at the channel borders. The development of this complex film rupture process, which is neither simply spinodal nor nucleation dewetting, can be mimicked precisely by making use of a novel simulation code based on a rigorous mathematical treatment of the thin film equation and on the knowledge of the effective interface potential of the system. The conditions that determine the appearance and the position of the satellite holes around pre-existing holes are discussed

  2. Satellite hole formation during dewetting: experiment and simulation

    CERN Document Server

    Neto, C; Seemann, R; Blossey, R; Becker, J; Grün, G

    2003-01-01

    The dewetting of thin polymer films on solid substrates has been studied extensively in recent years. These films can decay either by nucleation events or by spinodal dewetting, essentially only depending on the interface potential describing the short- and long-range intermolecular interactions between the interfaces and the initial film thickness. Here, we describe experiments and simulations concerned with the decay of polystyrene thin films. The rupture of the film occurs by the formation of a correlated pattern of holes ('satellite holes') along the liquid rims accumulating at the channel borders. The development of this complex film rupture process, which is neither simply spinodal nor nucleation dewetting, can be mimicked precisely by making use of a novel simulation code based on a rigorous mathematical treatment of the thin film equation and on the knowledge of the effective interface potential of the system. The conditions that determine the appearance and the position of the satellite holes around ...

  3. Pulsed laser dewetting of nickel catalyst for carbon nanofiber growth

    International Nuclear Information System (INIS)

    Guan, Y F; Pearce, R C; Simpson, M L; Rack, P D; Melechko, A V; Hensley, D K

    2008-01-01

    We present a pulsed laser dewetting technique that produces single nickel catalyst particles from lithographically patterned disks for subsequent carbon nanofiber growth through plasma enhanced chemical vapor deposition. Unlike the case for standard heat treated Ni catalyst disks, for which multiple nickel particles and consequently multiple carbon nanofibers (CNFs) are observed, single vertically aligned CNFs could be obtained from the laser dewetted catalyst. Different laser dewetting parameters were tested in this study, such as the laser energy density and the laser processing time measured by the total number of laser pulses. Various nickel disk radii and thicknesses were attempted and the resultant number of carbon nanofibers was found to be a function of the initial disk dimension and the number of laser pulses

  4. Oxygen-induced inhibition of silicon-on-insulator dewetting

    Energy Technology Data Exchange (ETDEWEB)

    Curiotto, S.; Leroy, F.; Cheynis, F.; Müller, P. [Aix Marseille Université, CNRS, CINaM UMR 7325, 13288 Marseille (France)

    2014-02-10

    We report that solid state dewetting of Si thin film on SiO{sub 2} can be reversibly inhibited by exposing the Si surface to a partial pressure of dioxygen (∼10{sup −7}Torr) at high temperature (∼1100K). Coupling in situ Low-Energy Electron Microscopy and ex situ atomic force microscopy we propose that the pinning of the contact line induced by the presence of small amounts of silicon oxide is the main physical process that inhibits the dewetting.

  5. Ordered arrays of Au catalysts by FIB assisted heterogeneous dewetting.

    Science.gov (United States)

    Benkouider, A; Ronda, A; David, T; Favre, L; Abbarchi, M; Naffouti, M; Osmond, J; Delobbe, A; Sudraud, P; Berbezier, I

    2015-12-18

    Synthesizing Au0.8Si0.2 nanocatalysts that are homogeneous in size and have controlled position is becoming a challenging and crucial prequisite for the fabrication of ordered semiconductor nanowires. In this study, Au0.8Si0.2 nanocatalysts are synthesized via dewetting of Au layers on Si(111) during thermal annealing in an ultra-high vacuum. In the first part of the paper, the mechanism of homogeneous dewetting is analyzed as a function of the Au-deposited thickness (h Au). We distinguish three different dewetting regimes: (I) for a low thickness ([Formula: see text]), a submonolyer coverage of Au is stabilized and there is no dewetting. (II) For an intermediate thickness ([Formula: see text]), there is both dewetting and Au0.8Si0.2 phase formation. The size and density of the Au0.8Si0.2 clusters are directly related to h Au. When cooling down to room temperature, the clusters decompose and reject the Si at the Au/Si substrate interface. (III) For a large thickness ([Formula: see text]), only dewetting takes place, without forming AuSi clusters. In this regime, the dewetting is kinetically controlled by the self-diffusion of Au (activation energy ∼0.43 eV) without evidence of an Si-alloying effect. As a practical consequence, when relying solely on the homogeneous dewetting of Au/Si(111) to form the Au0.8Si0.2 catalysts (without a supply of Si atoms from vapor), regime II should be used to obtain good size and density control. In the second part of the paper, a process for ordering the catalysts using focused ion beam-(FIB) assisted dewetting (heterogeneous dewetting) is developed. We show that no matter what the FIB milling conditions and the Au nominal thickness are, dewetting is promoted by ion beam irradiation and is accompanied by the formation of Au0.8Si0.2 droplets. The droplets preferentially form on the patterned areas, while in similar annealing conditions, they do not form on the unpatterned areas. This behavior is attributed to the larger Au

  6. Constitutional Due Process and Educational Administration.

    Science.gov (United States)

    Uerling, Donald F.

    1985-01-01

    Discusses substantive and procedural due process as required by the United States Constitution and interpreted by the Supreme Court, with particular reference to situations arising in educational environments. Covers interests protected by due process requirements, the procedures required, and some special considerations that may apply. (PGD)

  7. Procedural Due Process Rights in Student Discipline.

    Science.gov (United States)

    Pressman, Robert; Weinstein, Susan

    To assist administrators in understanding procedural due process rights in student discipline, this manual draws together hundreds of citations and case summaries of federal and state court decisions and provides detailed commentary as well. Chapter 1 outlines the general principles of procedural due process rights in student discipline, such as…

  8. Competition between dewetting and cross-linking in poly(N-vinylpyrrolidone)/polystyrene bilayer films.

    Science.gov (United States)

    Telford, Andrew M; Thickett, Stuart C; James, Michael; Neto, Chiara

    2011-12-06

    We investigated the dewetting of metastable poly(N-vinylpyrrolidone) (PNVP) thin films (45 nm) on top of polystyrene (PS) thin films (58 nm) as a function of annealing temperature and molecular weight of PS (96 and 6850 kg/mol). We focused on the competition between dewetting, occurring as a result of unfavorable intermolecular interactions at the PNVP/PS interface, and spontaneous cross-linking of PNVP, occurring during thermal annealing, as we recently reported (Telford, A. M.; James, M.; Meagher, L.; Neto, C. ACS Appl. Mater. Interfaces 2010, 2, 2399-2408). Using optical microscopy, we studied how the dewetting morphology and dynamics at different temperatures depended on the relative viscosity of the top PNVP film, which increased with cross-linking time, and of the bottom PS film. In the PNVP/PS96K system, cross-linking dominated over dewetting at temperatures below 180 °C, reducing drastically nucleated hole density and their maximum size, while above 180 °C the two processes reversed, with complete dewetting occurring at 200 °C. On the other hand, the PNVP/PS6850K system never achieved advanced dewetting stages as the dewetting was slower than cross-linking in the investigated temperature range. In both systems, dewetting of the PNVP films could be avoided altogether by thermally annealing the bilayers at temperatures where cross-linking dominated. The cross-linking was characterized quantitatively using neutron reflectometry, which indicated shrinkage and densification of the PNVP film, and qualitatively through selective removal of the bottom PS film. A simple model accounting for progressive cross-linking during the dewetting process predicted well the observed hole growth profiles and produced estimates of the PNVP cross-linking rate coefficients and of the activation energy of the process, in good agreement with literature values for similar systems. © 2011 American Chemical Society

  9. Dynamic dewetting through micropancake growth

    NARCIS (Netherlands)

    Seddon, James Richard Thorley; Bliznyuk, O.; Bliznyuk, Olesya; Kooij, Ernst S.; Poelsema, Bene; Zandvliet, Henricus J.W.; Lohse, Detlef

    2010-01-01

    We experimentally investigate the dynamics of nanometer-high, micrometer-wide gassy layers at the interface between a hydrophobic solid and bulk water. These micropancakes grow laterally in time, on the timescale of an hour, leading to partial dewetting of the solid. The growth is directional,

  10. On dewetting dynamics of solid films of hydrogen isotopes and its influence on tritium β spectroscopy

    International Nuclear Information System (INIS)

    Fleischmann, L.; Bonn, J.; Bornschein, B.; Otten, E.W.; Przyrembel, M.; Weinheimer, Ch.

    2000-01-01

    The dewetting dynamics of solid films of hydrogen isotopes, quench-condensed on a graphite substrate, was measured at various temperatures below desorption by observing the stray light from the film. A schematic model describing the dewetting process by surface diffusion is presented, which agrees qualitatively with our data. The activation energies of different hydrogen isotopes for surface diffusion were determined. The time constant for dewetting of a quench-condensed T 2 film at the working temperature of 1.86 K of the mainz neutrino mass experiment was extrapolated. (orig.)

  11. Nucleation mechanisms in high energy ion beam induced dewetting

    Energy Technology Data Exchange (ETDEWEB)

    Haag, Michael; Garmatter, Daniel; Ferhati, Redi; Amirthapandian, Sankarakumar; Bolse, Wolfgang [Institut fuer Halbleiteroptik und Funktionelle Grenzflaechen, Universitaet Stuttgart (Germany)

    2011-07-01

    Solid coatings, when heated above their melting points, often break up by forming small round holes, which then grow, coalesce and finally turn the initially contiguous film into a pattern of isolated droplets. Such dewetting has been intensively studied using thin polymer films on Si. Three different hole nucleation mechanisms were discovered: homogeneous (spontaneous) nucleation, heterogeneous nucleation at defects, and spinodal dewetting by self-amplifying capillary waves. We have recently found that swift heavy ion (SHI) irradiation of thin oxide films on Si results in similar dewetting patterns, even though the films were kept far below their melting points. Using our new in-situ SEM at the UNILAC accelerator of GSI, we were now able to identify the mechanisms behind this SHI induced dewetting phenomenon. By varying the film thickness and introducing defects at the interface, we can directly address the hole nucleation processes. Besides homogeneous and heterogeneous nucleation, we also found a process, which very much resembles the spinodal mechanism found for liquid polymers, although in the present case the instable wavy surface is not generated by capillary waves, but by ion beam induced stresses.

  12. Ordered alternating binary polymer nanodroplet array by sequential spin dewetting.

    Science.gov (United States)

    Bhandaru, Nandini; Das, Anuja; Salunke, Namrata; Mukherjee, Rabibrata

    2014-12-10

    We report a facile technique for fabricating an ordered array of nearly equal-sized mesoscale polymer droplets of two constituent polymers (polystyrene, PS and poly(methyl methacrylate), PMMA) arranged in an alternating manner on a topographically patterned substrate. The self-organized array of binary polymers is realized by sequential spin dewetting. First, a dilute solution of PMMA is spin-dewetted on a patterned substrate, resulting in an array of isolated PMMA droplets arranged along the substrate grooves due to self-organization during spin coating itself. The sample is then silanized with octadecyltrichlorosilane (OTS), and subsequently, a dilute solution of PS is spin-coated on to it, which also undergoes spin dewetting. The spin-dewetted PS drops having a size nearly equal to the pre-existing PMMA droplets position themselves between two adjacent PMMA drops under appropriate conditions, forming an alternating binary polymer droplet array. The alternating array formation takes place for a narrow range of solution concentration for both the polymers and depends on the geometry of the substrate. The size of the droplets depends on the extent of confinement, and droplets as small as 100 nm can be obtained by this method, on a suitable template. The findings open up the possibility of creating novel surfaces having ordered multimaterial domains with a potential multifunctional capability.

  13. Templated dewetting: designing entirely self-organized platforms for photocatalysis.

    Science.gov (United States)

    Altomare, Marco; Nguyen, Nhat Truong; Schmuki, Patrik

    2016-12-01

    Formation and dispersion of metal nanoparticles on oxide surfaces in site-specific or even arrayed configuration are key in various technological processes such as catalysis, photonics, electrochemistry and for fabricating electrodes, sensors, memory devices, and magnetic, optical, and plasmonic platforms. A crucial aspect towards an efficient performance of many of these metal/metal oxide arrangements is a reliable fabrication approach. Since the early works on graphoepitaxy in the 70s, solid state dewetting of metal films on patterned surfaces has been much explored and regarded as a most effective tool to form defined arrays of ordered metal particles on a desired substrate. While templated dewetting has been studied in detail, particularly from a mechanistic perspective on lithographically patterned Si surfaces, the resulting outstanding potential of its applications on metal oxide semiconductors, such as titania, has received only limited attention. In this perspective we illustrate how dewetting and particularly templated dewetting can be used to fabricate highly efficient metal/TiO 2 photocatalyst assemblies e.g. for green hydrogen evolution. A remarkable advantage is that the synthesis of such photocatalysts is completely based on self-ordering principles: anodic self-organized TiO 2 nanotube arrays that self-align to a highest degree of hexagonal ordering are an ideal topographical substrate for a second self-ordering process, that is, templated-dewetting of sputter-deposited metal thin films. The controllable metal/semiconductor coupling delivers intriguing features and functionalities. We review concepts inherent to dewetting and particularly templated dewetting, and outline a series of effective tools that can be synergistically interlaced to reach fine control with nanoscopic precision over the resulting metal/TiO 2 structures (in terms of e.g. high ordering, size distribution, site specific placement, alloy formation) to maximize their photocatalytic

  14. The dewetting properties of lotus leaves.

    Science.gov (United States)

    Zhang, Jihua; Sheng, Xianliang; Jiang, Lei

    2009-02-03

    The high dewetting abilities of lotus leaves can be transited to a complete wetting state by soaking the leaves in water at a depth of 50 cm for 2 h. However, after being dried by N2 gas, the high dewetting behavior of lotus leaves may be mostly restored. This indicates that experimental procedure might considerably affect the dewetting abilities of lotus leaves. To discover the mechanism underlying this interesting dewetting phenomena, the dewetting force was used to characterize the dewetting abilities of surfaces, and model studies to mimic the papillae were done. Surface hydrophobicity, sizes, rise angles, and secondary structures of the models' sides affected their dewetting force with water. So we suggested that the dewetting states, Cassie or Wenzel's state, of lotus surfaces depend much on the depth of water, i.e., the hydraulic pressure. On the other hand, the primary structures of papillae in Cassie's state led to a high receding angle with respect to the plane of the leaf during the dewetting measurement. The secondary structures and micro/nano arrays of papillae increased the dewetting abilities of lotus leaves, since no water intruded between papillae. However, the structures of papillae in Wenzle's state significantly reduced the dewetting abilities of lotus leaves after being soaked at a depth of 50 cm for 2 h. Therefore, as for novel designs of microdevices floating on water, including the use of the high dewetting properties of suphydrophobic materials, surface (primary or secondary) microstructure and external pressure, such as static hydraulic pressure, must be taken into account.

  15. Grain growth: The key to understand solid-state dewetting of silver thin films

    International Nuclear Information System (INIS)

    Jacquet, P.; Podor, R.; Ravaux, J.; Teisseire, J.; Gozhyk, I.; Jupille, J.; Lazzari, R.

    2016-01-01

    The dynamics of solid-state dewetting of polycrystalline silver thin films in oxygen atmosphere was investigated with in situ and real-time environmental Scanning Electron Microscopy at high temperature combined with Atomic Force Microscopy. Three steps were identified during dewetting: induction, hole propagation without specific rim and sintering. Moreover, it was observed that a very selective grain growth, promoted by surface diffusion, plays a key role all along the process.

  16. Contract Law, Due Process, and the NCAA.

    Science.gov (United States)

    Dickerson, Jaffe D.; Chapman, Mayer

    1978-01-01

    The NCAA has enjoyed almost total freedom from judicial scrutiny of its rules, procedures, and official acts in large part because of its private nature as an unincorporated association. The function of the NCAA, California State University, Hayward v NCAA, and due process of the student-athlete are discussed. (MLW)

  17. AFT Chief Promises Due-Process Reform

    Science.gov (United States)

    Sawchuk, Stephen

    2010-01-01

    The president of the American Federation of Teachers (AFT), Randi Weingarten, is putting the sensitive issue of due process on the education reform table, with a pledge to work with districts to streamline the often-cumbersome procedures for dismissing teachers who fail to improve their performance after receiving help and support. She has also…

  18. Templated assembly of Co-Pt nanoparticles via thermal and laser-induced dewetting of bilayer metal films.

    Science.gov (United States)

    Oh, Yong-Jun; Kim, Jung-Hwan; Thompson, Carl V; Ross, Caroline A

    2013-01-07

    Templated dewetting of a Co/Pt metal bilayer film on a topographic substrate was used to assemble arrays of Co-Pt alloy nanoparticles, with highly uniform particle size, shape and notably composition compared to nanoparticles formed on an untemplated substrate. Solid-state and liquid-state dewetting processes, using furnace annealing and laser irradiation respectively, were compared. Liquid state dewetting produced more uniform, conformal nanoparticles but they had a polycrystalline disordered fcc structure and relatively low magnetic coercivity. In contrast, solid state dewetting enabled formation of magnetically hard, ordered L1(0) Co-Pt single-crystal particles with coercivity >12 kOe. Furnace annealing converted the nanoparticles formed by liquid state dewetting into the L1(0) phase.

  19. Coupling of microphase separation and dewetting in weakly segregated diblock co-polymer ultrathin films.

    Science.gov (United States)

    Yan, Derong; Huang, Haiying; He, Tianbai; Zhang, Fajun

    2011-10-04

    We have studied the coupling behavior of microphase separation and autophobic dewetting in weakly segregated poly(ε-caprolactone)-block-poly(L-lactide) (PCL-b-PLLA) diblock co-polymer ultrathin films on carbon-coated mica substrates. At temperatures higher than the melting point of the PLLA block, the co-polymer forms a lamellar structure in bulk with a long period of L ∼ 20 nm, as determined using small-angle X-ray scattering. The relaxation procedure of ultrathin films with an initial film thickness of h = 10 nm during annealing has been followed by atomic force microscopy (AFM). In the experimental temperature range (100-140 °C), the co-polymer dewets to an ultrathin film of itself at about 5 nm because of the strong attraction of both blocks with the substrate. Moreover, the dewetting velocity increases with decreasing annealing temperatures. This novel dewetting kinetics can be explained by a competition effect of the composition fluctuation driven by the microphase separation with the dominated dewetting process during the early stage of the annealing process. While dewetting dominates the relaxation procedure and leads to the rupture of the ultrathin films, the composition fluctuation induced by the microphase separation attempts to stabilize them because of the matching of h to the long period (h ∼ 1/2L). The temperature dependence of these two processes leads to this novel relaxation kinetics of co-polymer thin films. © 2011 American Chemical Society

  20. Sub-10 nm structures on silicon by thermal dewetting of platinum

    International Nuclear Information System (INIS)

    Strobel, Sebastian; Kirkendall, Christopher; Chang, Jae-Byum; Berggren, Karl K

    2010-01-01

    A study of the dewetting behavior of platinum-thin-films on silicon was carried out to determine how variation of dewetting parameters affects the evolution of film morphology and to pinpoint which parameters yielded the smallest, most circular features. Platinum film thickness as well as dewetting time and temperature were varied and the film morphology characterized by means of scanning electron microscopy (SEM) analysis. Two different pathways of dewetting predicted in the literature (Vrij 1966 Discuss. Faraday Soc. 42 23, Becker et al 2003 Nat. Mater. 2 59-63) were observed. Depending on the initial criteria, restructuring of the film occurred via hole or droplet formation. With increased annealing time, a transition from an intermediate network structure to separated islands occurred. In addition, the formation of multilayered films, silicide crystals and nanowires occurred for certain parameters. Nevertheless, the dewetting behavior witnessed could be related to physical processes. Droplets with a mean diameter of 9 nm were formed by using a 1.5 nm thick platinum film annealed at 800 deg. C for 30 s. To demonstrate the suitability of the annealed films for further processing, we then used the dewetted films as masks for reactive ion etching to transfer the pattern into the silicon substrate, forming tapered nanopillars.

  1. Mechanically modulated dewetting by atomic force microscope for micro- and nano- droplet array fabrication.

    Science.gov (United States)

    Wang, Feifei; Li, Pan; Wang, Dong; Li, Longhai; Xie, Shuangxi; Liu, Lianqing; Wang, Yuechao; Li, Wen Jung

    2014-10-06

    Organizing a material into well-defined patterns during the dewetting process provides an attractive micro-/nano-fabrication method without using a conventional lithographic process, and hence, offers potential applications in organic electronics, optics systems, and memory devices. We report here how the mechanical modification of polymer surface by an Atomic Force Microscope (AFM) can be used to guide thin film dewetting evolution and break the intrinsic spatial correlation of spontaneous instability. An AFM is used to implement the mechanical modification of progressively narrow grids to investigate the influence of pattern size on the modulation of ultrathin polystyrene films dewetting evolution. For films with different initial thicknesses, when grid size is close to or below the characteristic wavelength of instability, the spinodal dewetting is suppressed, and film rupture is restricted to the cutting trench. We will show in this paper it is possible to generate only one droplet per gridded area on a thin film subsequent to nucleation dominated dewetting on a non-patterned substrate. Furthermore, when the grid periodicity exceeds the spinodal length, the number of droplets in predefined areas gradually approaches that associated with unconfined dewetting.

  2. High aspect ratio 10-nm-scale nanoaperture arrays with template-guided metal dewetting.

    Science.gov (United States)

    Wang, Ying Min; Lu, Liangxing; Srinivasan, Bharathi Madurai; Asbahi, Mohamed; Zhang, Yong Wei; Yang, Joel K W

    2015-04-10

    We introduce an approach to fabricate ordered arrays of 10-nm-scale silica-filled apertures in a metal film without etching or liftoff. Using low temperature (dewetting of metal films guided by nano-patterned templates, apertures with aspect ratios up to 5:1 are demonstrated. Apertures form spontaneously during the thermal process without need for further processing. Although the phenomenon of dewetting has been well studied, this is the first demonstration of its use in the fabrication of nanoapertures in a spatially controllable manner. In particular, the achievement of 10-nm length-scale patterning at high aspect ratio with thermal dewetting is unprecedented. By varying the nanotemplate design, we show its strong influence over the positions and sizes of the nanoapertures. In addition, we construct a three-dimensional phase field model of metal dewetting on nano-patterned substrates. The simulation data obtained closely corroborates our experimental results and reveals new insights to template dewetting at the nanoscale. Taken together, this fabrication method and simulation model form a complete toolbox for 10-nm-scale patterning using template-guided dewetting that could be extended to a wide range of material systems and geometries.

  3. Confinement induced ordering in dewetting of ultra-thin polymer bilayers on nanopatterned substrates.

    Science.gov (United States)

    Bhandaru, Nandini; Das, Anuja; Mukherjee, Rabibrata

    2016-01-14

    We report the dewetting of a thin bilayer of polystyrene (PS) and poly(methylmethacrylate) (PMMA) on a topographically patterned nonwettable substrate comprising an array of pillars, arranged in a square lattice. With a gradual increase in the concentration of the PMMA solution (Cn-PMMA), the morphology of the bottom layer changes to: (1) an aligned array of spin dewetted droplets arranged along substrate grooves at very low Cn-PMMA; (2) an interconnected network of threads surrounding each pillar at intermediate Cn-PMMA; and (3) a continuous bottom layer at higher Cn-PMMA. On the other hand the morphology of the PS top layer depends largely on the nature of the pre-existing bottom layer, in addition to Cn-PS. An ordered array of PMMA core-PS shell droplets forms right after spin coating when both Cn-PMMA and Cn-PS are very low. Bilayers with all other initial configurations evolve during thermal annealing, resulting in a variety of ordered structures. Unique morphologies realized include laterally coexisting structures of the two polymers confined within the substrate grooves due to initial rupture of the bottom layer on the substrate followed by a squeezing flow of the top layer; an array of core-shell and single polymer droplets arranged in an alternating order etc., to highlight a few. Such structures cannot be fabricated by any stand-alone lithography technique. On the other hand, in some cases the partially dewetted bottom layer imparts stability to an intact top PS layer against dewetting. Apart from ordering, under certain specific conditions significant miniaturization and downsizing of dewetted feature periodicity and dimension as compared to dewetting of a single layer on a flat substrate is observed. With the help of a morphology phase diagram we show that ordering is achieved over a wide combination of Cn-PMMA and Cn-PS, though the morphology and dewetting pathway differs significantly with variation in the thickness of the individual layers.

  4. Beyond the Young-Laplace model for cluster growth during dewetting of thin films: effective coarsening exponents and the role of long range dewetting interactions.

    Science.gov (United States)

    Constantinescu, Adi; Golubović, Leonardo; Levandovsky, Artem

    2013-09-01

    Long range dewetting forces acting across thin films, such as the fundamental van der Waals interactions, may drive the formation of large clusters (tall multilayer islands) and pits, observed in thin films of diverse materials such as polymers, liquid crystals, and metals. In this study we further develop the methodology of the nonequilibrium statistical mechanics of thin films coarsening within continuum interface dynamics model incorporating long range dewetting interactions. The theoretical test bench model considered here is a generalization of the classical Mullins model for the dynamics of solid film surfaces. By analytic arguments and simulations of the model, we study the coarsening growth laws of clusters formed in thin films due to the dewetting interactions. The ultimate cluster growth scaling laws at long times are strongly universal: Short and long range dewetting interactions yield the same coarsening exponents. However, long range dewetting interactions, such as the van der Waals forces, introduce a distinct long lasting early time scaling behavior characterized by a slow growth of the cluster height/lateral size aspect ratio (i.e., a time-dependent Young angle) and by effective coarsening exponents that depend on cluster size. In this study, we develop a theory capable of analytically calculating these effective size-dependent coarsening exponents characterizing the cluster growth in the early time regime. Such a pronounced early time scaling behavior has been indeed seen in experiments; however, its physical origin has remained elusive to this date. Our theory attributes these observed phenomena to ubiquitous long range dewetting interactions acting across thin solid and liquid films. Our results are also applicable to cluster growth in initially very thin fluid films, formed by depositing a few monolayers or by a submonolayer deposition. Under this condition, the dominant coarsening mechanism is diffusive intercluster mass transport while the

  5. Fabrication of poly-crystalline Si-based Mie resonators via amorphous Si on SiO2 dewetting.

    Science.gov (United States)

    Naffouti, Meher; David, Thomas; Benkouider, Abdelmalek; Favre, Luc; Ronda, Antoine; Berbezier, Isabelle; Bidault, Sebastien; Bonod, Nicolas; Abbarchi, Marco

    2016-02-07

    We report the fabrication of Si-based dielectric Mie resonators via a low cost process based on solid-state dewetting of ultra-thin amorphous Si on SiO2. We investigate the dewetting dynamics of a few nanometer sized layers annealed at high temperature to form submicrometric Si-particles. Morphological and structural characterization reveal the polycrystalline nature of the semiconductor matrix as well as rather irregular morphologies of the dewetted islands. Optical dark field imaging and spectroscopy measurements of the single islands reveal pronounced resonant scattering at visible frequencies. The linewidth of the low-order modes can be ∼20 nm in full width at half maximum, leading to a quality factor Q exceeding 25. These values reach the state-of-the-art ones obtained for monocrystalline Mie resonators. The simplicity of the dewetting process and its cost-effectiveness opens the route to exploiting it over large scales for applications in silicon-based photonics.

  6. A study on the correlation between the dewetting temperature of Ag film and SERS intensity.

    Science.gov (United States)

    Quan, Jiamin; Zhang, Jie; Qi, Xueqiang; Li, Junying; Wang, Ning; Zhu, Yong

    2017-11-07

    The thermally dewetted metal nano-islands have been actively investigated as cost-effective SERS-active substrates with a large area, good reproducibility and repeatability via simple fabrication process. However, the correlation between the dewetting temperature of metal film and SERS intensity hasn't been systematically studied. In this work, taking Ag nano-islands (AgNIs) as an example, we reported a strategy to investigate the correlation between the dewetting temperature of metal film and SERS intensity. We described the morphology evolution of AgNIs on the SiO 2 planar substrate in different temperatures and got the quantitative information in surface-limited diffusion process (SLDP) as a function of annealing temperature via classical mean-field nucleation theory. Those functions were further used in the simulation of electromagnetic field to obtain the correlation between the dewetting temperature of Ag film and theoretical analysis. In addition, Raman mapping was done on samples annealed at different temperatures, with R6G as an analyte, to accomplish the analysis of the correlation between the dewetting temperature of Ag film and SERS intensity, which is consistent with the theoretical analysis. For SLDP, we used the morphological characterization of five samples prepared by different annealing temperatures to successfully illustrate the change in SERS intensity with the temperature fluctuation, obtaining a small deviation between the experimental results and theoretic prediction.

  7. 130 MeV Au ion irradiation induced dewetting on In2Te3 thin film

    International Nuclear Information System (INIS)

    Matheswaran, P.; Abhirami, K.M.; Gokul, B.; Sathyamoorthy, R.; Prakash, Jai; Asokan, K.; Kanjilal, D.

    2012-01-01

    Highlights: ► In 2 Te 3 phase formed from In/Te bilayer by 130 MeV Au ion irradiation. ► Lower fluence results mixed phases with initial state of dewetting. ► At higher fluence, In 2 Te 3 phase with complete dewetting pattern is formed. ► Thermal spike model is used to explain the inter face mixing phenomena. ► SHI irradiation may be used to functionalize the structural and surface properties of thin films. - Abstract: In/Te bilayer thin films were prepared by sequential thermal evaporation and subsequently irradiated by 130 MeV Au ions. The pristine and irradiated samples were characterized by X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques. RBS spectra reveal the sputtering of Te film and interface mixing, with increasing fluence. The surface morphology showed the beginning of dewetting of Te thin film and formation of the partially connected with the mixed zones at the fluence of 1 × 10 13 ions/cm 2 . At the higher fluence of 3 × 10 13 ions/cm 2 , dewetted structures were isolated at the surface. Above results are explained based on the formation of craters, sputtering and dewetting followed by inter-diffusion at the interface of molten zones due to thermal spike induced by Au ions.

  8. Self-ordering of small-diameter metal nanoparticles by dewetting on hexagonal mesh templates.

    Science.gov (United States)

    Meshot, Eric R; Zhao, Zhouzhou; Lu, Wei; Hart, A John

    2014-09-07

    Arrays of small-diameter nanoparticles with high spatial order are useful for chemical and biological sensors, data storage, synthesis of nanowires and nanotubes, and many other applications. We show that self-ordered metal nanoparticle arrays can be formed by dewetting of thin films on hexagonal mesh substrates made of anodic aluminum oxide (AAO). Upon heating, the metal (Fe) film dewets onto the interstitial sites (i.e., the node points) between pores on the top surface of the AAO. We investigated the particle morphology and dynamics of dewetting using a combination of atomic force microscopy (AFM), grazing-incidence small-angle X-ray scattering (GISAXS), and numerical simulations. Templated metal particles are more monodisperse and have higher local order than those formed by the same dewetting process on flat, nonporous alumina. The degree of order depends on the initial film thickness, and for the optimal thickness tested (nominally 2 nm), we achieved uniform coverage and high order of the particles, comparable to that of the AAO template itself. Computational modeling of dewetting on templates with various pore order and size shows that the order of AAO pores is primarily influential in determining particle position and spacing, while the variance in pore size is less impactful. Potential uses of these ordered nanoparticle arrays on porous materials include plasmonic sensors and spatially controlled catalysts.

  9. Nanoscale Dewetting Transition in Protein Complex Folding

    Science.gov (United States)

    Hua, Lan; Huang, Xuhui; Liu, Pu; Zhou, Ruhong; Berne, Bruce J.

    2011-01-01

    In a previous study, a surprising drying transition was observed to take place inside the nanoscale hydrophobic channel in the tetramer of the protein melittin. The goal of this paper is to determine if there are other protein complexes capable of displaying a dewetting transition during their final stage of folding. We searched the entire protein data bank (PDB) for all possible candidates, including protein tetramers, dimers, and two-domain proteins, and then performed the molecular dynamics (MD) simulations on the top candidates identified by a simple hydrophobic scoring function based on aligned hydrophobic surface areas. Our large scale MD simulations found several more proteins, including three tetramers, six dimers, and two two-domain proteins, which display a nanoscale dewetting transition in their final stage of folding. Even though the scoring function alone is not sufficient (i.e., a high score is necessary but not sufficient) in identifying the dewetting candidates, it does provide useful insights into the features of complex interfaces needed for dewetting. All top candidates have two features in common: (1) large aligned (matched) hydrophobic areas between two corresponding surfaces, and (2) large connected hydrophobic areas on the same surface. We have also studied the effect on dewetting of different water models and different treatments of the long-range electrostatic interactions (cutoff vs PME), and found the dewetting phenomena is fairly robust. This work presents a few proteins other than melittin tetramer for further experimental studies of the role of dewetting in the end stages of protein folding. PMID:17608515

  10. Effects of copolymer composition, film thickness, and solvent vapor annealing time on dewetting of ultrathin block copolymer films.

    Science.gov (United States)

    Huang, Changchun; Wen, Gangyao; Li, Jingdan; Wu, Tao; Wang, Lina; Xue, Feifei; Li, Hongfei; Shi, Tongfei

    2016-09-15

    Effects of copolymer composition, film thickness, and solvent vapor annealing time on dewetting of spin-coated polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) films (dewetting of the films with different thicknesses occur via the spinodal dewetting and the nucleation and growth mechanisms, respectively. The PS-b-PMMA films rupture into droplets which first coalesce into large ones to reduce the surface free energy. Then the large droplets rupture into small ones to increase the contact area between PMMA blocks and acetone molecules resulting from ultimate migration of PMMA blocks to droplet surface, which is a novel dewetting process observed in spin-coated films for the first time. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Pathways to dewetting in hydrophobic confinement.

    Science.gov (United States)

    Remsing, Richard C; Xi, Erte; Vembanur, Srivathsan; Sharma, Sumit; Debenedetti, Pablo G; Garde, Shekhar; Patel, Amish J

    2015-07-07

    Liquid water can become metastable with respect to its vapor in hydrophobic confinement. The resulting dewetting transitions are often impeded by large kinetic barriers. According to macroscopic theory, such barriers arise from the free energy required to nucleate a critical vapor tube that spans the region between two hydrophobic surfaces--tubes with smaller radii collapse, whereas larger ones grow to dry the entire confined region. Using extensive molecular simulations of water between two nanoscopic hydrophobic surfaces, in conjunction with advanced sampling techniques, here we show that for intersurface separations that thermodynamically favor dewetting, the barrier to dewetting does not correspond to the formation of a (classical) critical vapor tube. Instead, it corresponds to an abrupt transition from an isolated cavity adjacent to one of the confining surfaces to a gap-spanning vapor tube that is already larger than the critical vapor tube anticipated by macroscopic theory. Correspondingly, the barrier to dewetting is also smaller than the classical expectation. We show that the peculiar nature of water density fluctuations adjacent to extended hydrophobic surfaces--namely, the enhanced likelihood of observing low-density fluctuations relative to Gaussian statistics--facilitates this nonclassical behavior. By stabilizing isolated cavities relative to vapor tubes, enhanced water density fluctuations thus stabilize novel pathways, which circumvent the classical barriers and offer diminished resistance to dewetting. Our results thus suggest a key role for fluctuations in speeding up the kinetics of numerous phenomena ranging from Cassie-Wenzel transitions on superhydrophobic surfaces, to hydrophobically driven biomolecular folding and assembly.

  12. Repeated Solid-state Dewetting of Thin Gold Films for Nanogap-rich Plasmonic Nanoislands.

    Science.gov (United States)

    Kang, Minhee; Park, Sang-Gil; Jeong, Ki-Hun

    2015-10-15

    This work reports a facile wafer-level fabrication for nanogap-rich gold nanoislands for highly sensitive surface enhanced Raman scattering (SERS) by repeating solid-state thermal dewetting of thin gold film. The method provides enlarged gold nanoislands with small gap spacing, which increase the number of electromagnetic hotspots and thus enhance the extinction intensity as well as the tunability for plasmon resonance wavelength. The plasmonic nanoislands from repeated dewetting substantially increase SERS enhancement factor over one order-of-magnitude higher than those from a single-step dewetting process and they allow ultrasensitive SERS detection of a neurotransmitter with extremely low Raman activity. This simple method provides many opportunities for engineering plasmonics for ultrasensitive detection and highly efficient photon collection.

  13. Wafer scale formation of monocrystalline silicon-based Mie resonators via silicon-on-insulator dewetting.

    Science.gov (United States)

    Abbarchi, Marco; Naffouti, Meher; Vial, Benjamin; Benkouider, Abdelmalek; Lermusiaux, Laurent; Favre, Luc; Ronda, Antoine; Bidault, Sébastien; Berbezier, Isabelle; Bonod, Nicolas

    2014-11-25

    Subwavelength-sized dielectric Mie resonators have recently emerged as a promising photonic platform, as they combine the advantages of dielectric microstructures and metallic nanoparticles supporting surface plasmon polaritons. Here, we report the capabilities of a dewetting-based process, independent of the sample size, to fabricate Si-based resonators over large scales starting from commercial silicon-on-insulator (SOI) substrates. Spontaneous dewetting is shown to allow the production of monocrystalline Mie-resonators that feature two resonant modes in the visible spectrum, as observed in confocal scattering spectroscopy. Homogeneous scattering responses and improved spatial ordering of the Si-based resonators are observed when dewetting is assisted by electron beam lithography. Finally, exploiting different thermal agglomeration regimes, we highlight the versatility of this technique, which, when assisted by focused ion beam nanopatterning, produces monocrystalline nanocrystals with ad hoc size, position, and organization in complex multimers.

  14. Multiscale Modeling of Dewetting Damage in Highly Filled Particulate Composites

    Science.gov (United States)

    Geubelle, P. H.; Inglis, H. M.; Kramer, J. D.; Patel, J. J.; Kumar, N. C.; Tan, H.

    2008-02-01

    Particle debonding or dewetting constitutes one of the key damage processes in highly filled particulate composites such as solid propellant and other energetic materials. To analyze this failure process, we have developed a multiscale finite element framework that combines, at the microscale, a nonlinear description of the binder response with a cohesive model of the damage process taking place in a representative periodic unit cell (PUC). To relate micro-scale damage to the macroscopic constitutive response of the material, we employ the mathematical theory of homogenization (MTH). After a description of the numerical scheme, we present the results of the damage response of a highly filled particulate composite subjected to a uniaxial macroscopic strain, and show the direct correlation between the complex damage processes taking place in the PUC and the nonlinear macroscopic constitutive response. We also present a detailed study of the PUC size and a comparison between the finite element MTH-based study and a micromechanics model of the dewetting process.

  15. Chemically-induced solid-state dewetting of thin Au films

    International Nuclear Information System (INIS)

    Gazit, Nimrod; Klinger, Leonid; Rabkin, Eugen

    2017-01-01

    We employed the solid state dewetting technique to produce nanoparticles of silver-gold alloy on a sapphire substrate. We deposited a thin gold layer on the substrate with alloy nanoparticles, and studied its thermal stability at low homological temperatures. We demonstrated that a large number of densely spaced holes form at the initial stages of dewetting of the gold layer with nanoparticles. A similar homogeneous gold film deposited on a bare sapphire substrate remained stable under identical annealing conditions, exhibiting the onset of dewetting at higher temperatures, and with a lower number of holes. We attributed the decreased thermal stability of the gold film deposited on the substrate with the silver-gold nanoparticles to accelerated grooving at the grain boundaries and triple junctions in the film. The grooving process is accelerated by the diffusion fluxes of Au atoms driven from the film towards the nanoparticles by the gradient of chemical potential. We developed a quantitative model of this chemically-induced dewetting process, and discussed its applicability for the design of better catalytic systems. Our work demonstrates that the chemical driving forces have to be reckoned with in the analysis of thermal stability of multicomponent thin films.

  16. Dewetting and Segregation of Zn-Doped InSb in Microgravity Experiments

    Science.gov (United States)

    Ostrogorsky, A. G.; Marin, C.; Duffar, T.; Volz, M.

    2009-01-01

    In directional solidification, dewetting is characterized by the lack of contact between the crystal and the crucible walls, due to the existence of a liquid meniscus at the level of the solid-liquid interface. This creates a gap of a few tens of micrometers between the crystal and the crucible. One of the immediate consequences of this phenomenon is the dramatic improvement of the quality of the crystal. This improvement is partly due to the modification of the solid-liquid interface curvature and partly to the absence of sticking and spurious nucleation at the crystal-crucible interface. Dewetting has been, commonly observed during the growth of semiconductors in crucibles under microgravity conditions where it appears to be very stable: the gap between the crystal and the crucible remains constant along several centimetres of growth. The physical models of the phenomenon are well established and they predict that dewetting should not occur in microgravity, if sufficient static pressure is imposed on the melt, pushing it towards the crucible. We present the results of InSb(Zn) solidification experiments conducted at the International Space Station (ISS) where, in spite of a spring exerting a pressure on the liquid, partial dewetting did occur. This surprising result is discussed in terms of force exerted .by the spring on the liquid and of possibility that the spring did not work properly. Furthermore, it appears that the segregation of the Zn was not affected by the occurrence of the dewetting. The data suggest that there was no significant interference of convection with segregation of Zn in InSb.

  17. Modelling approaches to the dewetting of evaporating thin films of nanoparticle suspensions

    International Nuclear Information System (INIS)

    Thiele, U; Vancea, I; Archer, A J; Robbins, M J; Frastia, L; Stannard, A; Pauliac-Vaujour, E; Martin, C P; Blunt, M O; Moriarty, P J

    2009-01-01

    We review recent experiments on dewetting thin films of evaporating colloidal nanoparticle suspensions (nanofluids) and discuss several theoretical approaches to describe the ongoing processes including coupled transport and phase changes. These approaches range from microscopic discrete stochastic theories to mesoscopic continuous deterministic descriptions. In particular, we describe (i) a microscopic kinetic Monte Carlo model, (ii) a dynamical density functional theory and (iii) a hydrodynamic thin film model. Models (i) and (ii) are employed to discuss the formation of polygonal networks, spinodal and branched structures resulting from the dewetting of an ultrathin 'postcursor film' that remains behind a mesoscopic dewetting front. We highlight, in particular, the presence of a transverse instability in the evaporative dewetting front, which results in highly branched fingering structures. The subtle interplay of decomposition in the film and contact line motion is discussed. Finally, we discuss a simple thin film model (iii) of the hydrodynamics on the mesoscale. We employ coupled evolution equations for the film thickness profile and mean particle concentration. The model is used to discuss the self-pinning and depinning of a contact line related to the 'coffee-stain' effect. In the course of the review we discuss the advantages and limitations of the different theories, as well as possible future developments and extensions.

  18. Nanopatterning Gold by Templated Solid State Dewetting on the Silica Warp and Weft of Diatoms

    Directory of Open Access Journals (Sweden)

    Jon Hiltz

    2016-01-01

    Full Text Available The diatom, Nitzschia palea, exhibits complex silica shell (frustule topography that resembles the warp and weft pattern of woven glass. The surface is perforated with a rhombic lattice of roughly oblong pores between periodically undulating transverse weft costae. Exfoliated frustules can be used to template gold nanoparticles by thermally induced dewetting of thin gold films. Acting as templates for the process, the frustules give rise to two coexisting hierarchies of particle sizes and patterned distributions of nanoparticles. By examining temperature dependent dewetting of 5, 10, and 15 nm Au films for various annealing times, we establish conditions for particle formation and patterning. The 5 nm film gives distributions of small particles randomly distributed over the surface and multiple particles at the rhombic lattice points in the pores. Thicker films yield larger faceted particles on the surface and particles that exhibit shapes that are roughly conformal with the shape of the pore container. The pores and costae are sources of curvature instabilities in the film that lead to mass transport of gold and selective accumulation in the weft valleys and pores. We suggest that, with respect to dewetting, the frustule comprises 2-dimensional sublattices of trapping sites. The pattern of dewetting is radically altered by interposing a self-assembled molecular adhesive of mercaptopropyltrimethoxysilane between the Au film overlayer and the frustule. By adjusting the interfacial energy in this manner, a fractal-like overlay of Au islands coexists with a periodic distribution of nanoparticles in the pores.

  19. On sub-T(g) dewetting of nanoconfined liquids and autophobic dewetting of crystallites.

    Science.gov (United States)

    Souda, Ryutaro

    2012-03-28

    The glass transition temperature (T(g)) of thin films is reduced by nanoconfinement, but it is also influenced by the free surface and substrate interface. To gain more insights into their contributions, dewetting behaviors of n-pentane, 3-methylpentane, and toluene films are investigated on various substrates as functions of temperature and film thickness. It is found that monolayers of these molecules exhibit sub-T(g) dewetting on a perfluoro-alkyl modified Ni substrate, which is attributable to the evolution of a 2D liquid. The onset temperature of dewetting increases with film thickness because fluidity evolves via cooperative motion of many molecules; sub-T(g) dewetting is observed for films thinner than 5 monolayers. In contrast, monolayers wet substrates of graphite, silicon, and amorphous solid water until crystallization occurs. The crystallites exhibit autophobic dewetting on the substrate covered with a wetting monolayer. The presence of premelting layers is inferred from the fact that n-pentane crystallites disappear on amorphous solid water via intermixing. Thus, the properties of quasiliquid formed on the crystallite surface differ significantly from those of the 2D liquid formed before crystallization.

  20. Stability and dewetting kinetics of thin gold films on Ti, TiOx and ZnO adhesion layers

    International Nuclear Information System (INIS)

    Schaefer, Brian T.; Cheung, Jeffrey; Ihlefeld, Jon F.; Jones, Jacob L.; Nagarajan, Valanoor

    2013-01-01

    We present an in situ high-temperature confocal laser microscopy study on the thermal stability of 40 nm thick gold thin films grown on 40 nm Ti, TiO x and ZnO adhesion layers on (0 0 1) Si. In situ observation of the dewetting process was performed over a wide range of set temperatures (400–800 °C) and ramp rates (10–50 °C min −1 ) for each gold/adhesion layer combination. We found that significant dewetting and subsequent formation of gold islands occurs only at and above 700 °C for all adhesion layers. The dewetting is driven to equilibrium for gold/ZnO compared to gold/Ti and gold/TiO x as confirmed by ex situ X-ray diffraction and scanning electron microscopy characterization. Quantification of the in situ data through stretched exponential kinetic models reveals an underlying apparent activation energy of the dewetting process. This energy barrier for dewetting is higher for gold/Ti and gold/TiO x compared to gold/ZnO, thus confirming the ex situ observations. We rationalize that these apparent activation energies correspond to the underlying thermal stability of each gold/adhesion layer system

  1. Suppression of dewetting phenomena during excimer laser melting of thin metal films on SiO2

    International Nuclear Information System (INIS)

    Kline, J.E.; Leonard, J.P.

    2005-01-01

    Pulsed excimer laser irradiation has been used to fully melt 200 nm films of elemental Au and Ni on SiO 2 substrates. With the use of a capping layer of SiO 2 and line irradiation via projection optics, the typical liquid-phase dewetting processes associated with these metals on SiO 2 has been suppressed. In a series of experiments varying line widths and fluence, a process region is revealed immediately above the complete melting threshold for which the films remain continuous and smooth after melting and resolidification. Simple energetic arguments for mechanisms leading to initiation of dewetting support these observations, and a gas-mediated model is proposed to describe the process conditions that are necessary for the suppression of dewetting

  2. A method for the formation of Pt metal nanoparticle arrays using nanosecond pulsed laser dewetting

    Energy Technology Data Exchange (ETDEWEB)

    Owusu-Ansah, Ebenezer; Horwood, Corie A.; Birss, Viola I.; Shi, Yujun J., E-mail: shiy@ucalgary.ca [Department of Chemistry, University of Calgary, Calgary, Alberta T2N 1N4 (Canada); El-Sayed, Hany A. [Institute for Technical Electrochemistry, Technische Universität München, D-85748 Garching (Germany)

    2015-05-18

    Nanosecond pulsed laser dewetting of Pt thin films, deposited on a dimpled Ta (DT) surface, has been studied here in order to form ordered Pt nanoparticle (NP) arrays. The DT substrate was fabricated via a simple electrochemical anodization process in a highly concentrated H{sub 2}SO{sub 4} and HF solution. Pt thin films (3–5 nm) were sputter coated on DT and then dewetted under vacuum to generate NPs using a 355 nm laser radiation (6–9 ns, 10 Hz). The threshold laser fluence to fully dewet a 3.5 nm thick Pt film was determined to be 300 mJ/cm{sup 2}. Our experiments have shown that shorter irradiation times (≤60 s) produce smaller nanoparticles with more uniform sizes, while longer times (>60 s) give large nanoparticles with wider size distributions. The optimum laser irradiation time of 1 s (10 pulses) has led to the formation of highly ordered Pt nanoparticle arrays with an average nanoparticle size of 26 ± 3 nm with no substrate deformation. At the optimum condition of 1 s and 500 mJ/cm{sup 2}, as many as 85% of the dewetted NPs were found neatly in the well-defined dimples. This work has demonstrated that pulsed laser dewetting of Pt thin films on a pre-patterned dimpled substrate is an efficient and powerful technique to produce highly ordered Pt nanoparticle arrays. This method can thus be used to produce arrays of other high-melting-point metal nanoparticles for a range of applications, including electrocatalysis, functionalized nanomaterials, and analytical purposes.

  3. Dewetting of polymer thin films on modified curved surfaces: preparation of polymer nanoparticles with asymmetric shapes by anodic aluminum oxide templates.

    Science.gov (United States)

    Liu, Chih-Ting; Tsai, Chia-Chan; Chu, Chien-Wei; Chi, Mu-Huan; Chung, Pei-Yun; Chen, Jiun-Tai

    2018-04-18

    We study the dewetting behaviors of poly(methyl methacrylate) (PMMA) thin films coated in the cylindrical nanopores of anodic aluminum oxide (AAO) templates by thermal annealing. Self-assembled monolayers (SAMs) of n-octadecyltrichlorosilane (ODTS) are introduced to modify the pore surfaces of the AAO templates to induce the dewetting process. By using scanning electron microscopy (SEM), the dewetting-induced morphology transformation from the PMMA thin films to PMMA nanoparticles with asymmetric shapes can be observed. The sizes of the PMMA nanoparticles can be controlled by the original PMMA solution concentrations. The dewetting phenomena on the modified nanopores are explained by taking into account the excess intermolecular interaction free energy (ΔG). This work opens a new possibility for creating polymer nanoparticles with asymmetric shapes in confined geometries.

  4. Pattern formation by dewetting and evaporating sedimenting suspensions

    NARCIS (Netherlands)

    Habibi, M.; Moller, P.; Fall, A.; Rafaï, S.; Bonn, D.

    2012-01-01

    Pattern formation from drying droplets containing sedimenting particles and dewetting of thin films of such suspensions was studied. The dewetting causes the formation of finger-like patterns near the contact line which leave behind a deposit of branches. We find that the strikingly low speed of

  5. Solid-state dewetting of continuous thin platinum coatings

    Energy Technology Data Exchange (ETDEWEB)

    Hanief, N. [University of Cape Town, Private Bag X3, Rondebosch 7701 (South Africa); Topić, M.; Pineda-Vargas, C. [iThemba LABS, National Research Foundation, P.O. Box 722, Somerset West (South Africa)

    2015-11-15

    Thermal stability of coatings is of crucial importance for reliability of electronic devices operating at high temperature. Thus, we investigated the Cr–Pt system where a thin platinum coating of 0.1 μm was deposited on chromium substrate and annealed at 1000 °C for 8 h. The scanning electron microscope (SEM) showed that a continuous and uniformly deposited Pt coating experienced the formation of “islands” after annealing. The grain-boundary grooving, dewetting and agglomeration were the main mechanisms of degradation of thermally annealed coatings. Results by μ-PIXE (particle-induced X-ray emission) and transmission electron microscope (TEM) showed the presence of Cr{sub 3}Pt phase in “islands” and the coating thickness was approximately 0.5 μm. The surrounding regions were left uncovered due to coating agglomeration at the expense of initially deposited coating.

  6. Scope and limitations of due process in administrative proceedings

    Directory of Open Access Journals (Sweden)

    Bernardo Carvajal Sánchez

    2010-12-01

    Full Text Available In order to explain in a better way the scope of Due Process in Administrative Law as a legal norm whose respect is essential to all government agencies, three points of view (formal, structural and material are proposed. Those items seem useful to understand “Administrative Due Process” in all its dimensions: as a constitutional norm developed by the enactment of laws and decrees; as a principle inspiring some conducts and new norms; and as an objective and subjective fundamental right. On the other hand, it is shown that Administrative Due Process is not an absolute rule because in some cases its full application is subject to normative relativism. Two opposite trends can be perceived at this point: in the first place, government agencies usually do not act the same way judges do, so Administrative Due Process should be distinguished from Judicial Due Process; therefore, it could actually have a more restricted scope. In the second place, some administrative authorities are nowadays playing a role more or less similar to what judges do. This means that new procedural guarantees will be claimed. In any case, admitting valid limitations to Administrative Due Process leads to the quest of the limits of these limitations. The application of the rule of Due Process cannot be totally suppressed; its scope cannot be completely reduced. This is the result of its fundamental nature as a legal norm that ensures justice and equity in all administrative procedures, and proscribes random decisions.

  7. Self-organization of yeast cells on modified polymer surfaces after dewetting: new perspectives in cellular patterning

    Energy Technology Data Exchange (ETDEWEB)

    Carnazza, S [Department of Microbiological, Genetic and Molecular Sciences, University of Messina, Messina (Italy); Satriano, S [Department of Chemical Sciences, University of Catania, Catania (Italy); Guglielmino, S [Department of Microbiological, Genetic and Molecular Sciences, University of Messina, Messina (Italy)

    2006-08-23

    In recent years, biological micro-electro-mechanical systems (commonly referred to as BioMEMS) have found widespread use, becoming increasingly prevalent in diagnostics and therapeutics. Cell-based sensors are nowadays gaining increasing attention, due to cellular built-in natural selectivity and physiologically relevant response to biologically active chemicals. On the other hand, surrogate microbial systems, including yeast models, have become a useful alternative to animal and mammalian cell systems for high-throughput screening for the identification of new pharmacological agents. A main obstacle in biosensor device fabrication is the need for localized geometric confinement of cells, without losing cell viability and sensing capability. Here we illustrate a new approach for cellular patterning using dewetting processes to control cell adhesion and spatial confinement on modified surfaces. By the control of simple system parameters, a rich variety of morphologies, ranging through hexagonal arrays, polygonal networks, bicontinuous structures, and elongated fingers, can be obtained.

  8. Dewetting-mediated pattern formation inside the coffee ring

    Science.gov (United States)

    Li, Weibin; Lan, Ding; Wang, Yuren

    2017-04-01

    The rearrangement of particles in the final stage of droplet evaporation has been investigated by utilizing differential interference contrast microscopy and the formation mechanism of a network pattern inside a coffee ring has been revealed. A tailored substrate with a circular hydrophilic domain is prepared to obtain thin liquid film containing monolayer particles. Real-time bottom-view images show that the evolution of a dry patch could be divided into three stages: rupture initiation, dry patch expansion, and drying of the residual liquid. A growing number of dry patches will repeat these stages to form the network patterns inside the ringlike stain. It can be shown that the suction effect promotes the rupture of the liquid film and the formation of the dry patch. The particle-assembling process is totally controlled by the liquid film dewetting and dominated by the surface tension of the liquid film, which eventually determine the ultimate deposition patterns.

  9. Self-assembly of bimetallic AuxPd1-x alloy nanoparticles via dewetting of bilayers through the systematic control of temperature, thickness, composition and stacking sequence

    Science.gov (United States)

    Kunwar, Sundar; Pandey, Puran; Sui, Mao; Bastola, Sushil; Lee, Jihoon

    2018-03-01

    Bimetallic alloy nanoparticles (NPs) are attractive materials for various applications with their morphology and elemental composition dependent optical, electronic, magnetic and catalytic properties. This work demonstrates the evolution of AuxPd1-x alloy nanostructures by the solid-state dewetting of sequentially deposited bilayers of Au and Pd on sapphire (0001). Various shape, size and configuration of AuxPd1‑x alloy NPs are fabricated by the systematic control of annealing temperature, deposition thickness, composition as well as stacking sequence. The evolution of alloy nanostructures is attributed to the surface diffusion, interface diffusion between bilayers, surface and interface energy minimization, Volmer-Weber growth model and equilibrium configuration. Depending upon the temperature, the surface morphologies evolve with the formation of pits, grains and voids and gradually develop into isolated semi-spherical alloy NPs by the expansion of voids and agglomeration of Au and Pd adatoms. On the other hand, small isolated to enlarged elongated and over-grown layer-like alloy nanostructures are fabricated due to the coalescence, partial diffusion and inter-diffusion with the increased bilayer thickness. In addition, the composition and stacking sequence of bilayers remarkably affect the final geometry of AuxPd1‑x nanostructures due to the variation in the dewetting process. The optical analysis based on the UV–vis-NIR reflectance spectra reveals the surface morphology dependent plasmonic resonance, scattering, reflection and absorption properties of AuxPd1‑x alloy nanostructures.

  10. The due diligence process for acquiring and building power plants

    International Nuclear Information System (INIS)

    Vallen, M.A.; Bullinger, C.D.

    1999-01-01

    The restructuring of the electric generating business is continuing at a torrid pace. New auctions of generation portfolios are initiated almost monthly, and announcements of new development projects arrive almost daily. It has become imperative, then, that participants in both acquisitions and development projects become conversant with the necessary due diligence process, a complex and critical task that can mean the difference between success and failure. A thorough due diligence process allows bidder/developers to uncover value and quantify liabilities before bidding/building, translating into the best analysis possible and resulting in a winning investment decision. This article describes the process by which buyers and developers approach and manage the due diligence process as a key step in making their investment decision

  11. Assembly of metallic nanoparticle arrays on glass via nanoimprinting and thin-film dewetting

    Directory of Open Access Journals (Sweden)

    Sun-Kyu Lee

    2017-05-01

    Full Text Available We propose a nanofabrication process to generate large-area arrays of noble metal nanoparticles on glass substrates via nanoimprinting and dewetting of metallic thin films. Glass templates were made via pattern transfer from a topographic Si mold to an inorganically cross-linked sol–gel (IGSG resist on glass using a two-layer polydimethylsiloxane (PDMS stamp followed by annealing, which turned the imprinted resist into pure silica. The transparent, topographic glass successfully templated the assembly of Au and Ag nanoparticle arrays via thin-film deposition and dewetting at elevated temperatures. The microstructural and mechanical characteristics that developed during the processes were discussed. The results are promising for low-cost mass fabrication of devices for several photonic applications.

  12. Morphology and Pattern Control of Diphenylalanine Self-Assembly via Evaporative Dewetting.

    Science.gov (United States)

    Chen, Jiarui; Qin, Shuyu; Wu, Xinglong; Chu, And Paul K

    2016-01-26

    Self-assembled peptide nanostructures have unique physical and biological properties and promising applications in electrical devices and functional molecular recognition. Although solution-based peptide molecules can self-assemble into different morphologies, it is challenging to control the self-assembly process. Herein, controllable self-assembly of diphenylalanine (FF) in an evaporative dewetting solution is reported. The fluid mechanical dimensionless numbers, namely Rayleigh, Marangoni, and capillary numbers, are introduced to control the interaction between the solution and FF molecules in the self-assembly process. The difference in the film thickness reflects the effects of Rayleigh and Marangoni convection, and the water vapor flow rate reveals the role of viscous fingering in the emergence of aligned FF flakes. By employing dewetting, various FF self-assembled patterns, like concentric and spokelike, and morphologies, like strips and hexagonal tubes/rods, can be produced, and there are no significant lattice structural changes in the FF nanostructures.

  13. Assembly of metallic nanoparticle arrays on glass via nanoimprinting and thin-film dewetting.

    Science.gov (United States)

    Lee, Sun-Kyu; Hwang, Sori; Kim, Yoon-Kee; Oh, Yong-Jun

    2017-01-01

    We propose a nanofabrication process to generate large-area arrays of noble metal nanoparticles on glass substrates via nanoimprinting and dewetting of metallic thin films. Glass templates were made via pattern transfer from a topographic Si mold to an inorganically cross-linked sol-gel (IGSG) resist on glass using a two-layer polydimethylsiloxane (PDMS) stamp followed by annealing, which turned the imprinted resist into pure silica. The transparent, topographic glass successfully templated the assembly of Au and Ag nanoparticle arrays via thin-film deposition and dewetting at elevated temperatures. The microstructural and mechanical characteristics that developed during the processes were discussed. The results are promising for low-cost mass fabrication of devices for several photonic applications.

  14. Influence of surfactants in forced dynamic dewetting.

    Science.gov (United States)

    Henrich, Franziska; Fell, Daniela; Truszkowska, Dorota; Weirich, Marcel; Anyfantakis, Manos; Nguyen, Thi-Huong; Wagner, Manfred; Auernhammer, Günter K; Butt, Hans-Jürgen

    2016-09-20

    In this work we show that the forced dynamic dewetting of surfactant solutions depends sensitively on the surfactant concentration. To measure this effect, a hydrophobic rotating cylinder was horizontally half immersed in aqueous surfactant solutions. Dynamic contact angles were measured optically by extrapolating the contour of the meniscus to the contact line. Anionic (sodium 1-decanesulfonate, S-1DeS), cationic (cetyl trimethylammonium bromide, CTAB) and nonionic surfactants (C 4 E 1 , C 8 E 3 and C 12 E 5 ) with critical micelle concentrations (CMCs) spanning four orders of magnitude were used. The receding contact angle in water decreased with increasing velocity. This decrease was strongly enhanced when adding surfactant, even at surfactant concentrations of 10% of the critical micelle concentration. Plots of the receding contact angle-versus-velocity almost superimpose when being plotted at the same relative concentration (concentration/CMC). Thus the rescaled concentration is the dominating property for dynamic dewetting. The charge of the surfactants did not play a role, thus excluding electrostatic effects. The change in contact angle can be interpreted by local surface tension gradients, i.e. Marangoni stresses, close to the three-phase contact line. The decrease of dynamic contact angles with velocity follows two regimes. Despite the existence of Marangoni stresses close to the contact line, for a dewetting velocity above 1-10 mm s -1 the hydrodynamic theory is able to describe the experimental results for all surfactant concentrations. At slower velocities an additional steep decrease of the contact angle with velocity was observed. Particle tracking velocimetry showed that the flow profiles do not differ with and without surfactant on a scales >100 μm.

  15. Directed ordering of phase separated domains and dewetting of thin polymer blend films on a topographically patterned substrate.

    Science.gov (United States)

    Bhandaru, Nandini; Karim, Alamgir; Mukherjee, Rabibrata

    2017-07-21

    Substrate pattern guided self-organization of ultrathin and confined polymeric films on a topographically patterned substrate is a useful approach for obtaining ordered meso and nano structures over large areas, particularly if the ordering is achieved during film preparation itself, eliminating any post-processing such as thermal or solvent vapor annealing. By casting a dilute solution of two immiscible polymers, polystyrene (PS) and polymethylmethacrylate (PMMA), from a common solvent (toluene) on a topographically patterned substrate with a grating geometry, we show the formation of self-organized meso patterns with various degrees of ordering. The morphology depends on both the concentration of the dispensed solution (C n ) and the blend composition (R B ). Depending on the extent of dewetting during spin coating, the final morphologies can be classified into three distinct categories. At a very low C n the solution dewets fully, resulting in isolated polymer droplets aligned along substrate grooves (Type 1). Type 2 structures comprising isolated threads with aligned phase separated domains along each substrate groove are observed at intermediate C n . A continuous film (Type 3) is obtained above a critical concentration (C n *) that depends on R B . While the extent of ordering of the domains gradually diminishes with an increase in film thickness for Type 3 patterns, the size of the domains remains much smaller than that on a flat substrate, resulting in significant downsizing of the features due to the lateral confinement imposed on the phase separation process by the topographic patterns. Finally, we show that some of these structures exhibit excellent broadband anti-reflection (AR) properties.

  16. Solid state de-wetting observed for vapor deposited copper films on carbon substrates

    International Nuclear Information System (INIS)

    Schrank, C.; Eisenmenger-Sittner, C.; Neubauer, E.; Bangert, H.; Bergauer, A.

    2004-01-01

    Copper-Carbon composites are a good example for novel materials consisting of components with extremely different physical and chemical properties. They have a high potential for an application as heat sinks for electronic components, but the joining of the two materials is a difficult task. To obtain reasonable mechanical and thermal contact between copper and carbon the following route was chosen. First glassy-carbon substrates were subjected to an RF-Nitrogen plasma treatment. Then 300 nm thick copper coatings were sputter-deposited on the plasma treated surface within the same vacuum chamber. Finally, the samples were removed from the deposition chamber and either investigated immediately or thermally annealed at 850 deg. C under high vacuum conditions (10 -4 Pa). While non-annealed copper-coatings were continuous and showed excellent adhesion values of approximately 700 N/cm 2 , the heat treated samples lose their continuity by a de-wetting process. At the beginning holes are formed, then a labyrinth-like morphology develops and finally the coating consists of isolated droplets. All these processes occur well below the melting temperature of copper and were observed by AFM and SEM. The mechanism of this solid-state de-wetting process is investigated in relation to the recent literature on de-wetting and its consequences on the manufacturing of copper-carbon composites are discussed

  17. Spinodal Theory: A Common Rupturing Mechanism in Spinodal Dewetting and Surface Directed Phase Separation (Some Technological Aspects: Spatial Correlations and the Significance of Dipole-Quadrupole Interaction in Spinodal Dewetting)

    International Nuclear Information System (INIS)

    Singh, S.P.; Singh, S.P.

    2011-01-01

    The emerging structures in spinodal dewetting of thin nano films and spinodal decomposition of binary mixtures are found to be similar with certain differences attributed to the nonlinearities inherent in the wetting forces. This paper deals with the technological aspects of the spinodal processes by giving a brief account of the theory and to correlate the two phenomena termed as spinodal dewetting of thin nano films and surface-directed phase separation. The MC simulation micrographs at early stage of spinodal dewetting of a (linear) polymer film confined between two hard walls (using FENE potential between the beads on same chain and Morse potential between inter and intra chain beads) show similarities with surface-directed phase separation (using metropolis algorithm) in creation of holes. The spinodal dewetting is also criticized on the basis of global minimization of free energy emerging from dipole-quadrupole interactions. A novel molecular scale-driving mechanism coming from asymmetric interface formation in spinodal processes is also proposed. It can be believed that the modeling done with the films under confinement of two walls works as a classical mathematical Ansatz to the dipole-quadrupole interaction coming from quantum origins and giving rise to lateral interactions in the process reflecting a colossal behavior in thin nano films though weak in nature

  18. Spinodal Theory: A Common Rupturing Mechanism in Spinodal Dewetting and Surface Directed Phase Separation (Some Technological Aspects: Spatial Correlations and the Significance of Dipole-Quadrupole Interaction in Spinodal Dewetting

    Directory of Open Access Journals (Sweden)

    Satya Pal Singh

    2011-01-01

    Full Text Available The emerging structures in spinodal dewetting of thin nano films and spinodal decomposition of binary mixtures are found to be similar with certain differences attributed to the nonlinearities inherent in the wetting forces. This paper deals with the technological aspects of the spinodal processes by giving a brief account of the theory and to correlate the two phenomena termed as spinodal dewetting of thin nanofilms and surface-directed phase separation. The MC simulation micrographs at early stage of spinodal dewetting of a (linear polymer film confined between two hard walls (using FENE potential between the beads on same chain and Morse potential between inter and intra chain beads show similarities with surface-directed phase separation (using metropolis algorithm in creation of holes. The spinodal dewetting is also criticized on the basis of global minimization of free energy emerging from dipole-quadrupole interactions. A novel molecular scale-driving mechanism coming from asymmetric interface formation in spinodal processes is also proposed. It can be believed that the modeling done with the films under confinement of two walls works as a classical mathematical ansatz to the dipole-quadrupole interaction coming from quantum origins and giving rise to lateral interactions in the process reflecting a colossal behavior in thin nano films though weak in nature.

  19. Dewetted growth of CdTe in microgravity (STS-95)

    International Nuclear Information System (INIS)

    Fiederle, M.; Babentsov, V.; Benz, K.W.; Duffar, T.; Dusserre, P.; Corregidor, V.; Dieguez, E.; Delaye, P.; Roosen, G.; Chevrier, V.; Launay, J.C.

    2004-01-01

    Two CdTe crystals had been grown in microgravity during the STS-95 mission. The growth configuration was dedicated to obtain dewetting of the crystals and to achieve high quality material. Background for the performed experiments was based on the theory of the dewetting and previous experience. The after flight characterization of the crystals has demonstrated existence of the dewetting areas of the crystals and their improved quality regarding the earth grown reference sample. The samples had been characterized by EDAX, Synchrotron X-ray topography, Photoluminescence and Optical and IR microscopy. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  20. Nanoparticles for dewetting suppression of thin polymer films used in chemical sensors

    International Nuclear Information System (INIS)

    Holmes, Melissa A.; Mackay, Michael E.; Giunta, Rachel K.

    2007-01-01

    Addition of fullerenes (C 60 or buckyballs) to a linear polymer has been found to eliminate dewetting when a thin (∼50 nm) film is exposed to solvent vapor. Based on neutron reflectivity measurements, it is found that the fullerenes form a coherent layer approximately 2 nm thick at the substrate - polymer film interface during the spin-coating process. The thickness and relative fullerene concentration (∼29 vol%) is not altered during solvent vapor annealing and it is thought this layer forms a solid-like buffer shielding the adverse van der Waals forces promoted by the underlying substrate. Several polymer films produced by spin- or spray-coating were tested on both silicon wafers and live surface acoustic wave sensors demonstrating fullerenes stabilize many different polymer types, prepared by different procedures and on various surfaces. Further, the fullerenes drastically improve sensor performance since dewetted films produce a sensor that is effectively inoperable

  1. Design of free patterns of nanocrystals with ad hoc features via templated dewetting

    Energy Technology Data Exchange (ETDEWEB)

    Aouassa, M.; Berbezier, I.; Favre, L.; Ronda, A. [IM2NP, CNRS, AMU, Marseille (France); Bollani, M.; Sordan, R. [LNES, Como (Italy); Delobbe, A.; Sudraud, P. [Orsay Physics, Fuveau (France)

    2012-07-02

    Design of monodisperse ultra-small nanocrystals (NCs) into large scale patterns with ad hoc features is demonstrated. The process makes use of solid state dewetting of a thin film templated through alloy liquid metal ion source focused ion beam (LMIS-FIB) nanopatterning. The solid state dewetting initiated at the edges of the patterns controllably creates the ordering of NCs with ad hoc placement and periodicity. The NC size is tuned by varying the nominal thickness of the film while their position results from the association of film retraction from the edges of the lay out and Rayleigh-like instability. The use of ultra-high resolution LMIS-FIB enables to produce monocrystalline NCs with size, periodicity, and placement tunable as well. It provides routes for the free design of nanostructures for generic applications in nanoelectronics.

  2. Sensitivity of Process Design due to Uncertainties in Property Estimates

    DEFF Research Database (Denmark)

    Hukkerikar, Amol; Jones, Mark Nicholas; Sarup, Bent

    2012-01-01

    The objective of this paper is to present a systematic methodology for performing analysis of sensitivity of process design due to uncertainties in property estimates. The methodology provides the following results: a) list of properties with critical importance on design; b) acceptable levels of...... in chemical processes. Among others vapour pressure accuracy for azeotropic mixtures is critical and needs to be measured or estimated with a ±0.25% accuracy to satisfy acceptable safety levels in design....

  3. 34 CFR 300.508 - Due process complaint.

    Science.gov (United States)

    2010-07-01

    ... attending; (5) A description of the nature of the problem of the child relating to the proposed or refused initiation or change, including facts relating to the problem; and (6) A proposed resolution of the problem... section, the hearing officer must make a determination on the face of the due process complaint of whether...

  4. "Ingraham v. Wright" and the Decline of Due Process.

    Science.gov (United States)

    Clark, Gerard J.

    1978-01-01

    Suggests that the constitutional questions in "Ingraham vs Wright" lend credence to a concern that the Court is seeking to eliminate all due process intervention outside of the incorporation and privacy cases and to limit even these cases to defenses of a criminal prosecution. Available from Suffolk University Law Review Office, 41…

  5. Teaching about Due Process of Law. ERIC Digest.

    Science.gov (United States)

    Vontz, Thomas S.

    Fundamental constitutional and legal principles are central to effective instruction in the K-12 social studies curriculum. To become competent citizens, students need to develop an understanding of the principles on which their society and government are based. Few principles are as important in the social studies curriculum as due process of…

  6. Basic Substantive Law for Paralegals: Contracts, Torts, and Due Process.

    Science.gov (United States)

    Marcin, Raymond B.

    Part of the paralegal, or legal assistant, training materials prepared by the National Paralegal Institution under a Federal grant, the text comprises an overview of the basic legal concepts usually found in introductory law courses concerning contracts, torts, and the due process area of constitutional law. Part 1, Contracts, covers: definition,…

  7. Measured spatial variability of beach erosion due to aeolian processes.

    NARCIS (Netherlands)

    de Vries, S.; Verheijen, A.H.; Hoonhout, B.M.; Vos, S.E.; Cohn, Nicholas; Ruggiero, P; Aagaard, T.; Deigaard, R.; Fuhrman, D.

    2017-01-01

    This paper shows the first results of measured spatial variability of beach erosion due to aeolian processes during the recently conducted SEDEX2 field experiment at Long Beach, Washington, U.S.A.. Beach erosion and sedimentation were derived using series of detailed terrestrial LIDAR measurements

  8. Texture evolution and microstructural changes during solid-state dewetting: A correlative study by complementary in situ TEM techniques

    International Nuclear Information System (INIS)

    Niekiel, Florian; Kraschewski, Simon M.; Schweizer, Peter; Butz, Benjamin; Spiecker, Erdmann

    2016-01-01

    The transition of a thin film into an energetically favorable set of particles at temperatures below the melting point of the bulk material is known as solid-state dewetting. In this work the dewetting behavior of 16 nm thick discontinuous Au thin films on amorphous silicon nitride membranes is quantitatively studied by complementary in situ transmission electron microscopy techniques taking advantage of the unique capabilities of a chip-based heating system. The combination of dedicated imaging and diffraction techniques is used to investigate the interplay of grain growth and texture evolution with the process of dewetting. The results show an initial coarsening of the microstructure preceding the other processes. Texture evolution is highly correlated to material retraction and agglomeration during the following dewetting process. In-plane grain rotation has been observed, acting as an additional mechanism for orientation changes. From a methodological perspective this work demonstrates the capabilities of today’s transmission electron microscopy in combination with state-of-the-art in situ instrumentation. In particular the combination of complementary information from different dedicated techniques in one and the same setup is demonstrated to be highly beneficial.

  9. Self-Assembly of Organic Ferroelectrics by Evaporative Dewetting: A Case of β-Glycine.

    Science.gov (United States)

    Seyedhosseini, Ensieh; Romanyuk, Konstantin; Vasileva, Daria; Vasilev, Semen; Nuraeva, Alla; Zelenovskiy, Pavel; Ivanov, Maxim; Morozovska, Anna N; Shur, Vladimir Ya; Lu, Haidong; Gruverman, Alexei; Kholkin, Andrei L

    2017-06-14

    Self-assembly of ferroelectric materials attracts significant interest because it offers a promising fabrication route to novel structures useful for microelectronic devices such as nonvolatile memories, integrated sensors/actuators, or energy harvesters. In this work, we demonstrate a novel approach for self-assembly of organic ferroelectrics (as exemplified by ferroelectric β-glycine) using evaporative dewetting, which allows forming quasi-regular arrays of nano- and microislands with preferred orientation of polarization axes. Surprisingly, self-assembled islands are crystallographically oriented in a radial direction from the center of organic "grains" formed during dewetting process. The kinetics of dewetting process follows the t -1/2 law, which is responsible for the observed polygon shape of the grain boundaries and island coverage as a function of radial position. The polarization in ferroelectric islands of β-glycine is parallel to the substrate and switchable under a relatively small dc voltage applied by the conducting tip of piezoresponse force microscope. Significant size effect on polarization is observed and explained within the Landau-Ginzburg-Devonshire phenomenological formalism.

  10. Fabrication of three-dimensional ordered nanodot array structures by a thermal dewetting method

    International Nuclear Information System (INIS)

    Li Zhenxing; Yoshino, Masahiko; Yamanaka, Akinori

    2012-01-01

    A new fabrication method for three-dimensional nanodot arrays with low cost and high throughput is developed in this paper. In this process, firstly a 2D nanodot array is fabricated by combination of top-down and bottom-up approaches. A nanoplastic forming technique is utilized as the top-down approach to fabricate a groove grid pattern on an Au layer deposited on a substrate, and self-organization by thermal dewetting is employed as the bottom-up approach. On the first-layer nanodot array, SiO 2 is deposited as a spacer layer. Au is then deposited on the spacer layer and thermal dewetting is conducted to fabricate a second-layer nanodot array. The effective parameters influencing dot formation on the second layer, including Au layer thickness and SiO 2 layer thickness, are studied. It is demonstrated that a 3D nanodot array of good vertical alignment is obtained by repeating the SiO 2 deposition, Au deposition and thermal dewetting. The mechanism of the dot agglomeration process is studied based on geometrical models. The effects of the spacer layer thickness and Au layer thickness on the morphology and alignment of the second-layer dots are discussed. (paper)

  11. Formation of patterned arrays of Au nanoparticles on SiC surface by template confined dewetting of normal and oblique deposited nanoscale films

    Energy Technology Data Exchange (ETDEWEB)

    Ruffino, F., E-mail: francesco.ruffino@ct.infn.it; Grimaldi, M.G.

    2013-06-01

    We report on the formation of patterned arrays of Au nanoparticles (NPs) on 6H SiC surface. To this end, we exploit the thermal-induced dewetting properties of a template confined deposited nanoscale Au film. In this approach, the Au surface pattern order, on the SiC substrate, is established by a template confined deposition using a micrometric template. Then, a dewetting process of the patterned Au film is induced by thermal processes. We compare the results, about the patterns formation, obtained for normal and oblique deposited Au films. We show that the normal and oblique depositions, through the same template, originate different patterns of the Au film. As a consequence of these different starting patterns, after the thermal processes, different patterns for the arrays of NPs originating from the dewetting mechanisms are obtained. For each fixed deposition angle α, the pattern evolution is analyzed, by scanning electron microscopy, as a function of the annealing time at 1173 K (900 °C). From these analyses, quantitative evaluations on the NPs size evolution are drawn. - Highlights: • Micrometric template-confined nanoscale gold films are deposited on silicon carbide. • The dewetting process of template-confined gold films on silicon carbide is studied. • Comparison of dewetting process of normal and oblique deposited gold films is drawn. • Patterned arrays of gold nanoparticles on silicon carbide surface are produced.

  12. Formation of patterned arrays of Au nanoparticles on SiC surface by template confined dewetting of normal and oblique deposited nanoscale films

    International Nuclear Information System (INIS)

    Ruffino, F.; Grimaldi, M.G.

    2013-01-01

    We report on the formation of patterned arrays of Au nanoparticles (NPs) on 6H SiC surface. To this end, we exploit the thermal-induced dewetting properties of a template confined deposited nanoscale Au film. In this approach, the Au surface pattern order, on the SiC substrate, is established by a template confined deposition using a micrometric template. Then, a dewetting process of the patterned Au film is induced by thermal processes. We compare the results, about the patterns formation, obtained for normal and oblique deposited Au films. We show that the normal and oblique depositions, through the same template, originate different patterns of the Au film. As a consequence of these different starting patterns, after the thermal processes, different patterns for the arrays of NPs originating from the dewetting mechanisms are obtained. For each fixed deposition angle α, the pattern evolution is analyzed, by scanning electron microscopy, as a function of the annealing time at 1173 K (900 °C). From these analyses, quantitative evaluations on the NPs size evolution are drawn. - Highlights: • Micrometric template-confined nanoscale gold films are deposited on silicon carbide. • The dewetting process of template-confined gold films on silicon carbide is studied. • Comparison of dewetting process of normal and oblique deposited gold films is drawn. • Patterned arrays of gold nanoparticles on silicon carbide surface are produced

  13. Dewetting acrylic polymer films with water/propylene carbonate/surfactant mixtures - implications for cultural heritage conservation.

    Science.gov (United States)

    Baglioni, M; Montis, C; Brandi, F; Guaragnone, T; Meazzini, I; Baglioni, P; Berti, D

    2017-09-13

    The removal of hydrophobic polymer films from surfaces is one of the top priorities of modern conservation science. Nanostructured fluids containing water, good solvents for polymers, either immiscible or partially miscible with water, and surfactants have been used in the last decade to achieve controlled removal. The dewetting of the polymer film is often an essential step to achieve efficient removal; however, the role of the surfactant throughout the process is yet to be fully understood. We report on the dewetting of a methacrylate/acrylate copolymer film induced by a ternary mixture of water, propylene carbonate (PC) and C 9-11 E 6 , a nonionic alcohol ethoxylate surfactant. The fluid microstructure was characterised through small angle X-ray scattering and the interactions between the film and water, water/PC and water/PC/C 9-11 E 6 , were monitored through confocal laser-scanning microscopy (CLSM) and analised both from a thermodynamic and a kinetic point of view. The presence of a surfactant is a prerequisite to induce dewetting of μm-thick films at room temperature, but it is not a thermodynamic driver. The amphiphile lowers the interfacial energy between the phases and favors the loss of adhesion of the polymer on glass, decreasing, in turn, the activation energy barrier, which can be overcome by the thermal fluctuations of polymer film stability, initiating the dewetting process.

  14. Thin film evolution equations from (evaporating) dewetting liquid layers to epitaxial growth

    International Nuclear Information System (INIS)

    Thiele, U

    2010-01-01

    In the present contribution we review basic mathematical results for three physical systems involving self-organizing solid or liquid films at solid surfaces. The films may undergo a structuring process by dewetting, evaporation/condensation or epitaxial growth, respectively. We highlight similarities and differences of the three systems based on the observation that in certain limits all of them may be described using models of similar form, i.e. time evolution equations for the film thickness profile. Those equations represent gradient dynamics characterized by mobility functions and an underlying energy functional. Two basic steps of mathematical analysis are used to compare the different systems. First, we discuss the linear stability of homogeneous steady states, i.e. flat films, and second the systematics of non-trivial steady states, i.e. drop/hole states for dewetting films and quantum-dot states in epitaxial growth, respectively. Our aim is to illustrate that the underlying solution structure might be very complex as in the case of epitaxial growth but can be better understood when comparing the much simpler results for the dewetting liquid film. We furthermore show that the numerical continuation techniques employed can shed some light on this structure in a more convenient way than time-stepping methods. Finally we discuss that the usage of the employed general formulation does not only relate seemingly unrelated physical systems mathematically, but does allow as well for discussing model extensions in a more unified way.

  15. Dewetting of nickel oxide-films on silicon under swift heavy ion irradiation

    International Nuclear Information System (INIS)

    Bolse, Thunu; Elsanousi, Ammar; Paulus, Hartmut; Bolse, Wolfgang

    2006-01-01

    Dewetting, occurring when a thin film on a non-wettable substrate turns into its liquid state, has gained strong interest during the last decade, since it results in nano-scale, large-area covering pattern formation. Recently we found that swift heavy ion (SHI) irradiation of thin NiO films on Si substrates at 80 K results in similar dewetting pattern, although in this case the coating has never reached its melting point. Careful inspection of the SEM images clearly revealed that the same nucleation mechanisms as observed for molten polymer films on Si (heterogeneous and homogeneous nucleation) were active. AFM shows that the circular holes formed in the early stages of the dewetting process exhibit a high and asymmetric rim-structure. RBS analysis was used to measure the coverage of the surface by the oxide films and revealed that the holes grow at constant velocity. This, and the shape of the rims, indicate that the material removed from the substrate surface piles up by plastic deformation, which points at a balance of the capillary driving forces and the hindered material dissipation

  16. Dewetting dynamics of a gold film on graphene: implications for nanoparticle formation.

    Science.gov (United States)

    Namsani, Sadanandam; Singh, Jayant K

    2016-01-01

    The dynamics of dewetting of gold films on graphene surfaces is investigated using molecular dynamics simulation. The effect of temperature (973-1533 K), film diameter (30-40 nm) and film thickness (0.5-3 nm) on the dewetting mechanism, leading to the formation of nanoparticles, is reported. The dewetting behavior for films ≤5 Å is in contrast to the behavior seen for thicker films. The retraction velocity, in the order of ∼300 m s(-1) for a 1 nm film, decreases with an increase in film thickness, whereas it increases with temperature. However at no point do nanoparticles detach from the surface within the temperature range considered in this work. We further investigated the self-assembly behavior of nanoparticles on graphene at different temperatures (673-1073 K). The process of self-assembly of gold nanoparticles is favorable at lower temperatures than at higher temperatures, based on the free-energy landscape analysis. Furthermore, the shape of an assembled structure is found to change from spherical to hexagonal, with a marked propensity towards an icosahedral structure based on the bond-orientational order parameters.

  17. Accelerating dewetting on deformable substrates by adding a liquid underlayer.

    Science.gov (United States)

    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.

  18. Dewetting and nanopattern formation of thin Pt films on SiO2 induced by ion beam irradiation

    International Nuclear Information System (INIS)

    Hu, Xiaoyuan; Cahill, David G.; Averback, Robert S.

    2001-01-01

    Dewetting and nanopattern formation of 3 - 10 nm Pt thin films upon ion irradiation is studied using scanning electron microscopy (SEM). Lateral feature size and the fraction of exposed surface area are extracted from SEM images and analyzed as functions of ion dose. The dewetting phenomenon has little temperature dependence for 3 nm Pt films irradiated by 800 keV Kr + at temperatures ranging from 80 to 823 K. At 893 K, the films dewet without irradiation, and no pattern formation is observed even after irradiation. The thickness of the Pt films, in the range 3 - 10 nm, influences the pattern formation, with the lateral feature size increasing approximately linearly with film thickness. The effect of different ion species and energies on the dewetting process is also investigated using 800 keV Kr + and Ar + irradiation and 19.5keVHe + , Ar + , Kr + , and Xe + irradiation. The lateral feature size and exposed surface fraction scale with energy deposition density (J/cm2) for all conditions except 19.5keVXe + irradiation. [copyright] 2001 American Institute of Physics

  19. Influences of ultra-thin Ti seed layers on the dewetting phenomenon of Au films deposited on Si oxide substrates

    Science.gov (United States)

    Kamiko, Masao; Kim, So-Mang; Jeong, Young-Seok; Ha, Jae-Ho; Koo, Sang-Mo; Ha, Jae-Geun

    2018-05-01

    The influences of a Ti seed layer (1 nm) on the dewetting phenomenon of Au films (5 nm) grown onto amorphous SiO2 substrates have been studied and compared. Atomic force microscopy results indicated that the introduction of Ti between the substrate and Au promoted the dewetting phenomenon. X-ray diffraction measurements suggested that the initial deposition of Ti promoted crystallinity of Au. A series of Auger electron spectroscopy and X-ray photoelectron spectroscopy results revealed that Ti transformed to a Ti oxide layer by reduction of the amorphous SiO2 substrate surface, and that the Ti seed layer remained on the substrate, without going through the dewetting process during annealing. We concluded that the enhancement of Au dewetting and the improvement in crystallinity of Au by the insertion of Ti could be attributed to the fact that Au location was changed from the surface of the amorphous SiO2 substrate to that of the Ti oxide layer.

  20. Shape-shifting colloids via stimulated dewetting

    Science.gov (United States)

    Youssef, Mena; Hueckel, Theodore; Yi, Gi-Ra; Sacanna, Stefano

    2016-01-01

    The ability to reconfigure elementary building blocks from one structure to another is key to many biological systems. Bringing the intrinsic adaptability of biological systems to traditional synthetic materials is currently one of the biggest scientific challenges in material engineering. Here we introduce a new design concept for the experimental realization of self-assembling systems with built-in shape-shifting elements. We demonstrate that dewetting forces between an oil phase and solid colloidal substrates can be exploited to engineer shape-shifting particles whose geometry can be changed on demand by a chemical or optical signal. We find this approach to be quite general and applicable to a broad spectrum of materials, including polymers, semiconductors and magnetic materials. This synthetic methodology can be further adopted as a new experimental platform for designing and rapidly prototyping functional colloids, such as reconfigurable micro swimmers, colloidal surfactants and switchable building blocks for self-assembly. PMID:27426418

  1. Slip-mediated dewetting of polymer microdroplets

    Science.gov (United States)

    McGraw, Joshua D.; Chan, Tak Shing; Maurer, Simon; Salez, Thomas; Benzaquen, Michael; Raphaël, Elie; Brinkmann, Martin; Jacobs, Karin

    2016-01-01

    Classical hydrodynamic models predict that infinite work is required to move a three-phase contact line, defined here as the line where a liquid/vapor interface intersects a solid surface. Assuming a slip boundary condition, in which the liquid slides against the solid, such an unphysical prediction is avoided. In this article, we present the results of experiments in which a contact line moves and where slip is a dominating and controllable factor. Spherical cap-shaped polystyrene microdroplets, with nonequilibrium contact angle, are placed on solid self-assembled monolayer coatings from which they dewet. The relaxation is monitored using in situ atomic force microscopy. We find that slip has a strong influence on the droplet evolutions, both on the transient nonspherical shapes and contact line dynamics. The observations are in agreement with scaling analysis and boundary element numerical integration of the governing Stokes equations, including a Navier slip boundary condition. PMID:26787903

  2. 130 MeV Au ion irradiation induced dewetting on In{sub 2}Te{sub 3} thin film

    Energy Technology Data Exchange (ETDEWEB)

    Matheswaran, P.; Abhirami, K.M.; Gokul, B. [Department of Physics, Kongunadu Arts and Science College, Coimbatore 641029 (India); Sathyamoorthy, R., E-mail: rsathya1959@gmail.com [Department of Physics, Kongunadu Arts and Science College, Coimbatore 641029 (India); Prakash, Jai [Department of Chemistry, M.M.H. College, Ghaziabad 201001 (India); Asokan, K.; Kanjilal, D. [Materials Science Division, Inter University Accelerator Centre, New Delhi 110067 (India)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer In{sub 2}Te{sub 3} phase formed from In/Te bilayer by 130 MeV Au ion irradiation. Black-Right-Pointing-Pointer Lower fluence results mixed phases with initial state of dewetting. Black-Right-Pointing-Pointer At higher fluence, In{sub 2}Te{sub 3} phase with complete dewetting pattern is formed. Black-Right-Pointing-Pointer Thermal spike model is used to explain the inter face mixing phenomena. Black-Right-Pointing-Pointer SHI irradiation may be used to functionalize the structural and surface properties of thin films. - Abstract: In/Te bilayer thin films were prepared by sequential thermal evaporation and subsequently irradiated by 130 MeV Au ions. The pristine and irradiated samples were characterized by X-ray diffraction (XRD), Rutherford backscattering spectrometry (RBS), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) techniques. RBS spectra reveal the sputtering of Te film and interface mixing, with increasing fluence. The surface morphology showed the beginning of dewetting of Te thin film and formation of the partially connected with the mixed zones at the fluence of 1 Multiplication-Sign 10{sup 13} ions/cm{sup 2}. At the higher fluence of 3 Multiplication-Sign 10{sup 13} ions/cm{sup 2}, dewetted structures were isolated at the surface. Above results are explained based on the formation of craters, sputtering and dewetting followed by inter-diffusion at the interface of molten zones due to thermal spike induced by Au ions.

  3. Solvent-vapor-assisted dewetting of prepatterned thin polymer films: control of morphology, order, and pattern miniaturization.

    Science.gov (United States)

    Bhandaru, Nandini; Goohpattader, Partho Sarathi; Faruqui, Danish; Mukherjee, Rabibrata; Sharma, Ashutosh

    2015-03-17

    Ultrathin (dewet by the growth of surface instability, the wavelength (λ) of which depends on the film thickness (h(f)). While the dewetting of a flat polymer thin film results in random structures, we show that the dewetting of a prepatterned film results in myriad ordered mesoscale morphologies under specific conditions. Such a film undergoes rupture over the thinnest parts when the initial local thickness of these zones (h(rm)) is lower than a limiting thickness h(lim) ≈ 10 nm. Additionally, the width of the pattern grooves (l(s)) must be wider than λ(s) corresponding to a flat film having a thickness of h(rm) for pattern-directed dewetting to take place over surface-tension-induced flattening. We first present an experimentally obtained morphology phase diagram that captures the conditions where a transition from surface-tension-induced flattening to pattern-directed-rupture takes place. Subsequently, we show the versatility of this technique in achieving a variety of aligned mesopatterns starting from a prepatterned film with simple grating geometry. The morphology of the evolving patterns depends on several parameters such as the initial film thickness (h(f)), prepattern amplitude (h(st)), duration of solvent vapor exposure (SVE), and wettability of the stamp used for patterning. Periodic rupture of the film at regular intervals imposes directionality on the evolving patterns, resulting in isolated long threads/cylindrical ridges of polymers, which subsequently disintegrate into an aligned array of droplets due to Rayleigh-Plateau instability under specific conditions. Other patterns such as a double periodic array of droplets and an array of holes are also possible to obtain. The evolution can be interrupted at any intermediate stage by terminating the solvent vapor annealing, allowing the creation of pattern morphology on demand. The created patterns are significantly miniaturized in size as compared to features obtained from dewetting a flat film with

  4. The Optical Properties of Cu-Ni Nanoparticles Produced via Pulsed Laser Dewetting of Ultrathin Films: The Effect of Nanoparticle Size and Composition on the Plasmon Response

    International Nuclear Information System (INIS)

    Wu, Yeuyeng; Fowlkes, Jason Davidson; Rack, Philip D.

    2011-01-01

    Thin film Cu-Ni alloys ranging from 2-8nm were synthesized and their optical properties were measured as-deposited and after a laser treatment which dewet the films into arrays of spatially correlated nanoparticles. The resultant nanoparticle size and spacing are attributed to laser induced spinodal dewetting process. The evolution of the spinodal dewetting process is investigated as a function of the thin film composition which ultimately dictates the size distribution and spacing of the nanoparticles. The optical measurements of the copper rich alloy nanoparticles reveal a signature absorption peak suggestive of a plasmonic peak which red-shifts with increasing nanoparticle size and blue shifts and dampens with increasing nickel concentration.

  5. Polymer underlayer assisted dewetting of a top metal nanofilm

    International Nuclear Information System (INIS)

    Abeysinghe, Don C; Chen Weibin; Zhan Qiwen; Nelson, Robert E

    2009-01-01

    We demonstrated polymethylmethacrylate (PMMA) polymer underlayer assisted, focused-ion-beam (FIB)-induced dewetting of a top Au nanofilm where we found that the underlayer played a prominent and, in some cases, a useful role in the dewetting of the top layer. For an Au nanofilm deposited on a thick uniform PMMA underlayer, where the underlayer is stable and therefore does not dewet, irregularly spaced Au nanoparticles (AuNPs) were formed as expected by raster-scanning of a focused Ga-ion beam. On the other hand, topographically pre-patterned thin PMMA film provided heterogeneous nucleation sites for both the Au top layer and the PMMA underlayer to initiate dewetting at and guidance for forming regularly spaced AuNPs with much narrower size distribution at significantly lower ion dose levels when compared to the thick, uniform underlayer case. We also found that the underlayer assisted dewetting in this case relaxes the restriction on pre-pattern periodicity to obtain a single NP per pattern period, which is a noteworthy departure from the pre-patterned solid substrate case. FIB-induced AuNP areas can have sharp boundaries and can be positioned on a selected area of a substrate with high positional accuracy, which is important for the implementation of devices in sensing, nano-optics/photonics, and optoelectronic applications.

  6. Templated Solid-State Dewetting of Thin Silicon Films.

    Science.gov (United States)

    Naffouti, Meher; David, Thomas; Benkouider, Abdelmalek; Favre, Luc; Delobbe, Anne; Ronda, Antoine; Berbezier, Isabelle; Abbarchi, Marco

    2016-11-01

    Thin film dewetting can be efficiently exploited for the implementation of functionalized surfaces over very large scales. Although the formation of sub-micrometer sized crystals via solid-state dewetting represents a viable method for the fabrication of quantum dots and optical meta-surfaces, there are several limitations related to the intrinsic features of dewetting in a crystalline medium. Disordered spatial organization, size, and shape fluctuations are relevant issues not properly addressed so far. This study reports on the deterministic nucleation and precise positioning of Si- and SiGe-based nanocrystals by templated solid-state dewetting of thin silicon films. The dewetting dynamics is guided by pattern size and shape taking full control over number, size, shape, and relative position of the particles (islands dimensions and relative distances are in the hundreds nm range and fluctuate ≈11% for the volumes and ≈5% for the positioning). © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Dewetting Properties of Metallic Liquid Film on Nanopillared Graphene

    Science.gov (United States)

    Li, Xiongying; He, Yezeng; Wang, Yong; Dong, Jichen; Li, Hui

    2014-01-01

    In this work, we report simulation evidence that the graphene surface decorated by carbon nanotube pillars shows strong dewettability, which can give it great advantages in dewetting and detaching metallic nanodroplets on the surfaces. Molecular dynamics (MD) simulations show that the ultrathin liquid film first contracts then detaches from the graphene on a time scale of several nanoseconds, as a result of the inertial effect. The detaching velocity is in the order of 10 m/s for the droplet with radii smaller than 50 nm. Moreover, the contracting and detaching behaviors of the liquid film can be effectively controlled by tuning the geometric parameters of the liquid film or pillar. In addition, the temperature effects on the dewetting and detaching of the metallic liquid film are also discussed. Our results show that one can exploit and effectively control the dewetting properties of metallic nanodroplets by decorating the surfaces with nanotube pillars. PMID:24487279

  8. Robust nanopatterning by laser-induced dewetting of metal nanofilms

    International Nuclear Information System (INIS)

    Favazza, Christopher; Kalyanaraman, Ramki; Sureshkumar, Radhakrishna

    2006-01-01

    We have observed nanopattern formation with robust and controllable spatial ordering by laser-induced dewetting in nanoscopic metal films. Pattern evolution in Co film of thickness 1≤h≤8 nm on SiO 2 was achieved under multiple pulse irradiation using a 9 ns pulse laser. Dewetting leads to the formation of cellular patterns which evolve into polygons that eventually break up into nanoparticles with unimodal size distribution and short range ordering in nearest neighbour spacing R. Spatial ordering was attributed to a hydrodynamic thin film instability and resulted in a predictable variation of R and particle diameter D with h. The length scales R and D were found to be independent of the laser energy. These results suggest that spatially ordered metal nanoparticles can be robustly assembled by laser-induced dewetting

  9. Robust nanopatterning by laser-induced dewetting of metal nanofilms

    Energy Technology Data Exchange (ETDEWEB)

    Favazza, Christopher [Department of Physics, Washington University in St Louis, MO 63130 (United States); Kalyanaraman, Ramki [Department of Physics, Washington University in St Louis, MO 63130 (United States); Sureshkumar, Radhakrishna [Center for Materials Innovation, Washington University in St Louis, MO 63130 (United States)

    2006-08-28

    We have observed nanopattern formation with robust and controllable spatial ordering by laser-induced dewetting in nanoscopic metal films. Pattern evolution in Co film of thickness 1{<=}h{<=}8 nm on SiO{sub 2} was achieved under multiple pulse irradiation using a 9 ns pulse laser. Dewetting leads to the formation of cellular patterns which evolve into polygons that eventually break up into nanoparticles with unimodal size distribution and short range ordering in nearest neighbour spacing R. Spatial ordering was attributed to a hydrodynamic thin film instability and resulted in a predictable variation of R and particle diameter D with h. The length scales R and D were found to be independent of the laser energy. These results suggest that spatially ordered metal nanoparticles can be robustly assembled by laser-induced dewetting.

  10. Robust nanopatterning by laser-induced dewetting of metal nanofilms.

    Science.gov (United States)

    Favazza, Christopher; Kalyanaraman, Ramki; Sureshkumar, Radhakrishna

    2006-08-28

    We have observed nanopattern formation with robust and controllable spatial ordering by laser-induced dewetting in nanoscopic metal films. Pattern evolution in Co film of thickness 1≤h≤8 nm on SiO(2) was achieved under multiple pulse irradiation using a 9 ns pulse laser. Dewetting leads to the formation of cellular patterns which evolve into polygons that eventually break up into nanoparticles with unimodal size distribution and short range ordering in nearest neighbour spacing R. Spatial ordering was attributed to a hydrodynamic thin film instability and resulted in a predictable variation of R and particle diameter D with h. The length scales R and D were found to be independent of the laser energy. These results suggest that spatially ordered metal nanoparticles can be robustly assembled by laser-induced dewetting.

  11. Cellular Dewetting: Opening of Macroapertures in Endothelial Cells

    Science.gov (United States)

    Gonzalez-Rodriguez, David; Maddugoda, Madhavi P.; Stefani, Caroline; Janel, Sebastien; Lafont, Frank; Cuvelier, Damien; Lemichez, Emmanuel; Brochard-Wyart, Françoise

    2012-05-01

    Pathogenic bacteria can cross from blood vessels to host tissues by opening transendothelial cell macroapertures (TEMs). To induce TEM opening, bacteria intoxicate endothelial cells with proteins that disrupt the contractile cytoskeletal network. Cell membrane tension is no longer resisted by contractile fibers, leading to the opening of TEMs. Here we model the opening of TEMs as a new form of dewetting. While liquid dewetting is irreversible, we show that cellular dewetting is transient. Our model predicts the minimum radius for hole nucleation, the maximum TEM size, and the dynamics of TEM opening, in good agreement with experimental data. The physical model is then coupled with biological experimental data to reveal that the protein missing in metastasis (MIM) controls the line tension at the rim of the TEM and opposes its opening.

  12. Wetting-dewetting films: the role of structural forces.

    Science.gov (United States)

    Nikolov, Alex; Wasan, Darsh

    2014-04-01

    The liquid wetting and dewetting of solids are ubiquitous phenomena that occur in everyday life. Understanding the nature of these phenomena is beneficial for research and technological applications. However, despite their importance, the phenomena are still not well understood because of the nature of the substrate's surface energy non-ideality and dynamics. This paper illustrates the mechanisms and applications of liquid wetting and dewetting on hydrophilic and hydrophobic substrates. We discuss the classical understanding and application of wetting and film stability criteria based on the Frumkin-Derjaguin disjoining pressure model. The roles of the film critical thickness and capillary pressure on the film instability based on the disjoining pressure isotherm are elucidated, as are the criteria for stable and unstable wet films. We consider the film area in the model for the film stability and the applicable experiments. This paper also addresses the two classic film instability mechanisms for suspended liquid films based on the conditions of the free energy criteria originally proposed by de Vries (nucleation hole formation) and Vrij-Scheludko (capillary waves vs. van der Waals forces) that were later adapted to explain dewetting. We include a discussion of the mechanisms of nanofilm wetting and dewetting on a solid substrate based on nanoparticles' tendency to form a 2D layer and 2D inlayer in the film under the wetting film's surface confinement. We also present our view on the future of wetting-dewetting modeling and its applications in developing emerging technologies. We believe the review and analysis presented here will benefit the current and future understanding of the wetting-dewetting phenomena, as well as aid in the development of novel products and technologies. © 2013.

  13. Ion induced spinodal dewetting of thin solid films

    Energy Technology Data Exchange (ETDEWEB)

    Repetto, Luca; Setina Batic, Barbara; Firpo, Giuseppe; Piano, Emanuele; Valbusa, Ugo [Dipartimento di Fisica, Universita di Genova, Via Dodecaneso 33, 16146 Genova (Italy)

    2012-05-28

    We present experimental data and numerical simulations in order to show that the mechanism of spinodal dewetting is active during ion beam irradiation of thin solid films. The expected scaling law for the characteristic wavelengths versus the initial film thickness is modified by the presence of sputtering. The conclusion is fully supported by model simulation which shows a square law dependence for null sputtering yield and a bimodal trend when sputtering is included. This result is in contrast to earlier studies and opens the possibility to control and use ion induced dewetting for the fabrication of functional nanostructures.

  14. Cross-sectional characterization of the dewetting of a Au/Ni bilayer film

    Energy Technology Data Exchange (ETDEWEB)

    Cen, Xi; Thron, Andrew M.; Zhang, Xinming; Benthem, Klaus van

    2017-07-15

    The solid state dewetting of Au/Ni bilayer films was investigated by cross-sectional transmission electron microscopy techniques, including energy-dispersive X-ray spectroscopy, electron energy-loss spectroscopy and precession electron diffraction. After annealing under high vacuum conditions the early stage of film agglomeration revealed significant changes in film morphology and chemical distribution. Both Au and Ni showed texturing. Despite the initial deposition sequence of the as-deposited Au/Ni/SiO{sub 2}/Si interface structure, the majority of the metal/SiO{sub 2} interface was Au/SiO{sub 2} after annealing at 675 °C for 1 h. Void nucleation was predominantly observed at Au/Ni/SiO{sub 2} triple junctions, rather than grain boundary grooving at free surface of the metal film. Detailed cross-sectional characterization reveals that the Au/Ni interface in addition to small amounts of metal alloying strongly affects film break-up and agglomeration kinetics. The formation of Au/SiO{sub 2} interface sections is found to be energetically preferred over Ni/SiO{sub 2} due to compressive stress in the as-deposited Ni layer. Void nucleation is observed at the film/substrate interface, while the formation of voids at Ni/Au phase boundaries inside the metal film is caused by the Kirkendall effect. - Highlights: • The dewetting of Au/Ni bilayer films was studied by cross-sectional TEM techniques. • The majority of the metal/SiO{sub 2} interface was comprised of Au/SiO{sub 2} after annealing. • Void formation was dominant for hole nucleation at early dewetting stage. • The Kirkendall effect was also observed to cause the formation of voids.

  15. Smooth perfluorinated surfaces with different chemical and physical natures: their unusual dynamic dewetting behavior toward polar and nonpolar liquids.

    Science.gov (United States)

    Cheng, Dalton F; Masheder, Benjamin; Urata, Chihiro; Hozumi, Atsushi

    2013-09-10

    The effects of surface chemistry and the mobility of surface-tethered functional groups of various perfluorinated surfaces on their dewetting behavior toward polar (water) and nonpolar (n-hexadecane, n-dodecane, and n-decane) liquids were investigated. In this study, three types of common smooth perfluorinated surfaces, that is, a perfluoroalkylsilane (heptadecafluoro-1,1,2,2-tetrahydrooctyl-dimethylchlorosilane, FAS17) monomeric layer, an amorphous fluoropolymer film (Teflon AF 1600), and a perfluorinated polyether (PFPE)-terminated polymer brush film (Optool DSX), were prepared and their static/dynamic dewetting characteristics were compared. Although the apparent static contact angles (CAs) of these surfaces with all probe liquids were almost identical to each other, the ease of movement of liquid drops critically depended on the physical (solidlike or liquidlike) natures of the substrate surface. CA hysteresis and substrate tilt angles (TAs) of all probe liquids on the Optool DSX surface were found to be much lower than those of Teflon AF1600 and FAS17 surfaces due to its physical polymer chain mobility at room temperature and the resulting liquidlike nature. Only 6.0° of substrate incline was required to initiate movement for a small drop (5 μL) of n-decane, which was comparable to the reported substrate TA value (5.3°) for a superoleophobic surface (θ(S) > 160°, textured perfluorinated surface). Such unusual dynamic dewetting behavior of the Optool DSX surface was also markedly enhanced due to the significant increase in the chain mobility of PFPE by moderate heating (70 °C) of the surface, with substrate TA reducing to 3.0°. CA hysteresis and substrate TAs rather than static CAs were therefore determined to be of greater consequence for the estimation of the actual dynamic dewetting behavior of alkane probe liquids on these smooth perfluorinated surfaces. Their dynamic dewettability toward alkane liquids is in the order of Optool DSX > Teflon AF1600

  16. In situ investigation of ion-induced dewetting of a thin iron-oxide film on silicon by high resolution scanning electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Amirthapandian, S. [Institut fuer Halbleiteroptik und Funktionelle Grenzflaechen, Universitaet Stuttgart, 70569 Stuttgart (Germany); Material Physics Division, Materials Science Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102 (India); Schuchart, F.; Garmatter, D.; Bolse, W. [Institut fuer Halbleiteroptik und Funktionelle Grenzflaechen, Universitaet Stuttgart, 70569 Stuttgart (Germany)

    2012-11-15

    Using our new in situ high resolution scanning electron microscope, which is integrated into the UNILAC ion beamline at the Helmholtzzentrum fuer Schwerionenforschung (GSI) in Darmstadt, Germany, we investigated the swift heavy ion induced dewetting of a thin iron oxide layer on Si. Besides heterogeneous hole nucleation at defects and spontaneous (homogeneous) hole nucleation, we could clearly identify a dewetting mechanism, which is similar to the spinodal dewetting observed for liquid films. Instead of being due to capillary waves, it is based on a stress induced surface instability. The latter results in the formation of a wavy surface with constant dominant wave-length and increasing amplitude during ion irradiation. Dewetting sets in as soon as the wave-troughs reach the film-substrate interface. Inspection of the hole radii and rim shapes indicates that removal of the material from the hole area occurs mainly by plastic deformation at the inner boundary and ion induced viscous flow in the peripheral zone due to surface tension.

  17. Effect of argon implantation on solid-state dewetting: control of size and surface density of silicon nanocrystals.

    Science.gov (United States)

    Almadori, Y; Borowik, Ł; Chevalier, N; Barbé, J-C

    2017-01-27

    Thermally induced solid-state dewetting of ultra-thin films on insulators is a process of prime interest, since it is capable of easily forming nanocrystals. If no particular treatment is performed to the film prior to the solid-state dewetting, it is already known that the size, the shape and the density of nanocrystals is governed by the initial film thickness. In this paper, we report a novel approach to control the size and the surface density of silicon nanocrystals based on an argon-implantation preliminary surface treatment. Using 7.5 nm thin layers of silicon, we show that increasing the implantation dose tends to form smaller silicon nanocrystals with diameter and height lower than 50 nm and 30 nm, respectively. Concomitantly, the surface density is increased by a factor greater than 20, going from 5 μm -2 to values over 100 μm -2 .

  18. The effect of different thickness alumina capping layers on the final morphology of dewet thin Ni films

    Science.gov (United States)

    White, Benjamin C.; Behbahanian, Amir; Stoker, T. McKay; Fowlkes, Jason D.; Hartnett, Chris; Rack, Phillip D.; Roberts, Nicholas A.

    2018-03-01

    Nanoparticles on a substrate have numerous applications in nanotechnology, from enhancements to solar cell efficiency to improvements in carbon nanotube growth. Producing nanoparticles in a cost effective fashion with control over size and spacing is desired, but difficult to do. This work presents a scalable method for altering the radius and pitch distributions of nickel nanoparticles. The introduction of alumina capping layers to thin nickel films during a pulsed laser-induced dewetting process has yielded reductions in the mean and standard deviation of radii and pitch for dewet nanoparticles with no noticeable difference in final morphology with increased capping layer thickness. The differences in carbon nanotube mats grown, on the uncapped sample and one of the capped samples, is also presented here, with a more dense mat being present for the capped case.

  19. Theory Of Dewetting In A Filled Elastomer Under Stress

    Science.gov (United States)

    Peng, Steven T. J.

    1993-01-01

    Report presents theoretical study of dewetting between elastomeric binder and filler particles of highly filled elastomer under multiaxial tension and resulting dilatation of elastomer. Study directed toward understanding and predicting nonlinear stress-vs.-strain behavior of filled elastomeric rocket propellant, also applicable to rubber in highly loaded tire or in damping pad.

  20. Electric field induced dewetting at polymer/polymer interfaces

    NARCIS (Netherlands)

    Lin, Z.Q.; Kerle, T.; Russell, T.P.; Schäffer, E.; Steiner, U

    2002-01-01

    External electric fields were used to amplify interfacial fluctuations in the air/polymer/polymer system where one polymer dewets the other. Two different hydrodynamic regimes were found as a function of electric field strength. If heterogeneous nucleation leads to the formation of holes before the

  1. Thickness-dependent spontaneous dewetting morphology of ultrathin Ag films.

    Science.gov (United States)

    Krishna, H; Sachan, R; Strader, J; Favazza, C; Khenner, M; Kalyanaraman, R

    2010-04-16

    We show here that the morphological pathway of spontaneous dewetting of ultrathin Ag films on SiO2 under nanosecond laser melting is dependent on film thickness. For films with thickness h of 2 nm < or = h < or = 9.5 nm, the morphology during the intermediate stages of dewetting consisted of bicontinuous structures. For films with 11.5 nm < or = h < or = 20 nm, the intermediate stages consisted of regularly sized holes. Measurement of the characteristic length scales for different stages of dewetting as a function of film thickness showed a systematic increase, which is consistent with the spinodal dewetting instability over the entire thickness range investigated. This change in morphology with thickness is consistent with observations made previously for polymer films (Sharma and Khanna 1998 Phys. Rev. Lett. 81 3463-6; Seemann et al 2001 J. Phys.: Condens. Matter 13 4925-38). Based on the behavior of free energy curvature that incorporates intermolecular forces, we have estimated the morphological transition thickness for the intermolecular forces for Ag on SiO2. The theory predictions agree well with observations for Ag. These results show that it is possible to form a variety of complex Ag nanomorphologies in a consistent manner, which could be useful in optical applications of Ag surfaces, such as in surface enhanced Raman sensing.

  2. Thickness-dependent spontaneous dewetting morphology of ultrathin Ag films

    Energy Technology Data Exchange (ETDEWEB)

    Krishna, H; Favazza, C [Department of Physics, Washington University in St Louis, MO 63130 (United States); Sachan, R; Strader, J; Kalyanaraman, R [Department of Material Science and Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Khenner, M, E-mail: ramki@utk.edu [Department of Mathematics, Western Kentucky University, Bowling Green, KY 42101 (United States)

    2010-04-16

    We show here that the morphological pathway of spontaneous dewetting of ultrathin Ag films on SiO{sub 2} under nanosecond laser melting is dependent on film thickness. For films with thickness h of 2 nm {<=} h {<=} 9.5 nm, the morphology during the intermediate stages of dewetting consisted of bicontinuous structures. For films with 11.5 nm {<=} h {<=} 20 nm, the intermediate stages consisted of regularly sized holes. Measurement of the characteristic length scales for different stages of dewetting as a function of film thickness showed a systematic increase, which is consistent with the spinodal dewetting instability over the entire thickness range investigated. This change in morphology with thickness is consistent with observations made previously for polymer films (Sharma and Khanna 1998 Phys. Rev. Lett. 81 3463-6; Seemann et al 2001 J. Phys.: Condens. Matter 13 4925-38). Based on the behavior of free energy curvature that incorporates intermolecular forces, we have estimated the morphological transition thickness for the intermolecular forces for Ag on SiO{sub 2}. The theory predictions agree well with observations for Ag. These results show that it is possible to form a variety of complex Ag nanomorphologies in a consistent manner, which could be useful in optical applications of Ag surfaces, such as in surface enhanced Raman sensing.

  3. Dewetting of Epitaxial Silver Film on Silicon by Thermal Annealing

    Science.gov (United States)

    Sanders, Charlotte E.; Kellogg, Gary L.; Shih, C.-K.

    2013-03-01

    It has been shown that noble metals can grow epitaxially on semiconducting and insulating substrates, despite being a non-wetting system: low temperature deposition followed by room temperature annealing leads to atomically flat film morphology. However, the resulting metastable films are vulnerable to dewetting, which has limited their utility for applications under ambient conditions. The physics of this dewetting is of great interest but little explored. We report on an investigation of the dewetting of epitaxial Ag(111) films on Si(111) and (100). Low energy electron microscopy (LEEM) shows intriguing evolution in film morphology and crystallinity, even at temperatures below 100oC. On the basis of these findings, we can begin to draw compelling inferences about film-substrate interaction and the kinetics of dewetting. Financial support is from NSF, DGE-0549417 and DMR-0906025. This work was performed, in part, at the Center for Integrated Nanotechnologies, User Facility operated for the U.S. DOE Office of Science. Sandia National Lab is managed and operated by Sandia Corp., a subsidiary of Lockheed Martin Corp., for the U.S. DOE's National Nuclear Security Administration under DE-AC04-94AL85000.

  4. Polymer Film Dewetting by Water/Surfactant/Good-Solvent Mixtures: A Mechanistic Insight and Its Implications for the Conservation of Cultural Heritage.

    Science.gov (United States)

    Baglioni, Michele; Montis, Costanza; Chelazzi, David; Giorgi, Rodorico; Berti, Debora; Baglioni, Piero

    2018-06-18

    Aqueous nanostructured fluids (NSFs) have been proposed to remove polymer coatings from the surface of works of art; this process usually involves film dewetting. The NSF cleaning mechanism was studied using several techniques that were employed to obtain mechanistic insight on the interaction of a methacrylic/acrylic copolymer (Paraloid B72) film laid on glass surfaces and several NSFs, based on two solvents and two surfactants. The experimental results provide a detailed picture of the dewetting process. The gyration radius and the reduction of the T g of Paraloid B72 fully swollen in the two solvents is larger for propylene carbonate than for methyl ethyl ketone, suggesting higher mobility of polymer chains for the former, while a nonionic alcohol ethoxylate surfactant was more effective than sodium dodecylsulfate in favoring the dewetting process. FTIR 2D imaging showed that the dewetting patterns observed on model samples are also present on polymer-coated mortar tiles when exposed to NSFs. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Effects due to spectator interaction in deep inelastic processes

    International Nuclear Information System (INIS)

    Smilga, A.V.

    1979-01-01

    The simplest diagrams describing interaction with the spectator in the e - π→e - + hadrons deep inelastic process are considered. The contribution of the final state interaction diagram to the structure function considerable in the Feynman gauge is suppressed under the temporal gauge choice in accordance with the results of the naive parton model. The expressin for the cross section of the process when large quark momentum is transferred to the spectator is derived

  6. Micropatterned Surfaces for Atmospheric Water Condensation via Controlled Radical Polymerization and Thin Film Dewetting.

    Science.gov (United States)

    Wong, Ian; Teo, Guo Hui; Neto, Chiara; Thickett, Stuart C

    2015-09-30

    Inspired by an example found in nature, the design of patterned surfaces with chemical and topographical contrast for the collection of water from the atmosphere has been of intense interest in recent years. Herein we report the synthesis of such materials via a combination of macromolecular design and polymer thin film dewetting to yield surfaces consisting of raised hydrophilic bumps on a hydrophobic background. RAFT polymerization was used to synthesize poly(2-hydroxypropyl methacrylate) (PHPMA) of targeted molecular weight and low dispersity; spin-coating of PHPMA onto polystyrene films produced stable polymer bilayers under appropriate conditions. Thermal annealing of these bilayers above the glass transition temperature of the PHPMA layer led to complete dewetting of the top layer and the formation of isolated PHPMA domains atop the PS film. Due to the vastly different rates of water nucleation on the two phases, preferential dropwise nucleation of water occurred on the PHPMA domains, as demonstrated by optical microscopy. The simplicity of the preparation method and ability to target polymers of specific molecular weight demonstrate the value of these materials with respect to large-scale water collection devices or other materials science applications where patterning is required.

  7. Raman and photoluminescence spectroscopy of SiGe layer evolution on Si(100) induced by dewetting

    Science.gov (United States)

    Shklyaev, A. A.; Volodin, V. A.; Stoffel, M.; Rinnert, H.; Vergnat, M.

    2018-01-01

    High temperature annealing of thick (40-100 nm) Ge layers deposited on Si(100) at ˜400 °C leads to the formation of continuous films prior to their transformation into porous-like films due to dewetting. The evolution of Si-Ge composition, lattice strain, and surface morphology caused by dewetting is analyzed using scanning electron microscopy, Raman, and photoluminescence (PL) spectroscopies. The Raman data reveal that the transformation from the continuous to porous film proceeds through strong Si-Ge interdiffusion, reducing the Ge content from 60% to about 20%, and changing the stress from compressive to tensile. We expect that Ge atoms migrate into the Si substrate occupying interstitial sites and providing thereby the compensation of the lattice mismatch. Annealing generates only one type of radiative recombination centers in SiGe resulting in a PL peak located at about 0.7 and 0.8 eV for continuous and porous film areas, respectively. Since annealing leads to the propagation of threading dislocations through the SiGe/Si interface, we can tentatively associate the observed PL peak to the well-known dislocation-related D1 band.

  8. Dewetting-Induced Photoluminescent Enhancement of Poly(lauryl methacrylate)/Quantum Dot Thin Films.

    Science.gov (United States)

    Geldmeier, Jeffrey; Rile, Lexy; Yoon, Young Jun; Jung, Jaehan; Lin, Zhiqun; Tsukruk, Vladimir V

    2017-12-19

    A new method for enhancing photoluminescence from quantum dot (QD)/polymer nanocomposite films is proposed. Poly(lauryl methacrylate) (PLMA) thin films containing embedded QDs are intentionally allowed to undergo dewetting on substrates by exposure to a nonsolvent vapor. After controlled dewetting, films exhibited typical dewetting morphologies with increased amounts of scattering that served to outcouple photoluminescence from the film and reduce internal light propagation within the film. Up to a 5-fold enhancement of the film emission was achieved depending on material factors such as the initial film thickness and QD concentration within the film. An increase in initial film thickness was shown to increase the dewetted maximum feature size and its characteristic length until a critical thickness was reached where dewetting became inhibited. A unique light exposure-based photopatterning method is also presented for the creation of high contrast emissive patterns as guided by spatially controlled dewetting.

  9. Film thickness dependence of phase separation and dewetting behaviors in PMMA/SAN blend films.

    Science.gov (United States)

    You, Jichun; Liao, Yonggui; Men, Yongfeng; Shi, Tongfei; An, Lijia

    2010-09-21

    Film thickness dependence of complex behaviors coupled by phase separation and dewetting in blend [poly(methyl methacrylate) (PMMA) and poly(styrene-ran-acrylonitrile) (SAN)] films on silicon oxide substrate at 175 °C was investigated by grazing incidence ultrasmall-angle X-ray scattering (GIUSAX) and in situ atomic force microscopy (AFM). It was found that the dewetting pathway was under the control of the parameter U(q0)/E, which described the initial amplitude of the surface undulation and original thickness of film, respectively. Furthermore, our results showed that interplay between phase separation and dewetting depended crucially on film thickness. Three mechanisms including dewetting-phase separation/wetting, dewetting/wetting-phase separation, and phase separation/wetting-pseudodewetting were discussed in detail. In conclusion, it is relative rates of phase separation and dewetting that dominate the interplay between them.

  10. In-situ investigation of thermal instabilities and solid state dewetting in polycrystalline platinum thin films via confocal laser microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jahangir, S.; Cheng, Xuan; Huang, H. H.; Nagarajan, V. [School of Materials Science and Engineering, University of New South Wales, Sydney 2052 (Australia); Ihlefeld, J. [Electronic, Optical, and Nanomaterials Department, Sandia National Laboratories, Albuquerque, New Mexico 87185 (United States)

    2014-10-28

    Solid state dewetting and the subsequent morphological changes for platinum thin films grown on zinc oxide (ZnO) buffered (001) silicon substrates (Pt/ZnO/SiO{sub 2}/(001)Si system) is investigated under vacuum conditions via a custom-designed confocal laser microscope coupled with a laser heating system. Live imaging of thin film dewetting under a range of heating and quenching vacuum ambients reveals events including hillock formation, hole formation, and hole growth that lead to formation of a network of Pt ligaments, break up of Pt ligaments to individual islands and subsequent Pt islands shape reformation, in chronological fashion. These findings are corroborated by ex-situ materials characterization and quantitative electron microscopy analysis. A secondary hole formation via blistering before film rupture is revealed to be the critical stage, after which a rapid dewetting catastrophe occurs. This process is instantaneous and cannot be captured by ex-situ methods. Finally, an intermetallic phase forms at 900 °C and alters the morphology of Pt islands, suggesting a practical limit to the thermal environments that may be used for these platinized silicon wafers in vacuum conditions.

  11. Controlling the alloy composition of PtNi nanocrystals using solid-state dewetting of bilayer films

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Okkyun; Oh, Se An; Lee, Ji Yeon; Ha, Sung Soo; Kim, Jae Myung; Choi, Jung Won; Kim, Jin-Woo [Department of Physics and Photon Science & School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005 (Korea, Republic of); Kang, Hyon Chol [Department of Materials and Science Engineering, Chosun University, Gwangju 61542 (Korea, Republic of); Noh, Do Young, E-mail: dynoh@gist.ac.kr [Department of Physics and Photon Science & School of Materials Science and Engineering, Gwangju Institute of Science and Technology, Gwangju 61005 (Korea, Republic of)

    2016-05-15

    We demonstrate that solid-state dewetting of bilayer films is an effective way for obtaining bimetallic alloy nanocrystals of controlled composition. When a Pt–Ni bilayer film were annealed near 700 °C, Pt and Ni atoms inter-diffused to form a PtNi bimetallic alloy film. Upon annealing at higher temperatures, the bilayer films transformed into <111> oriented PtNi alloy nanocrystals in small-rhombicuboctahedron shape through solid-state dewetting process. The Pt content of the nanocrystals and the alloy films, estimated by applying the Vegard's law to the relaxed lattice constant, was closely related to the thickness of each layer in the as-grown bilayer films which can be readily controlled during bilayer deposition. - Highlights: • Composition control of PtNi nanoparticles using solid state dewetting is proposed. • PtNi alloy composition was controlled by thickness ratio of Pt–Ni bilayer films. • PtNi alloy nanocrystals were obtained in small-rhombicuboctahedron shape.

  12. In-situ investigation of thermal instabilities and solid state dewetting in polycrystalline platinum thin films via confocal laser microscopy

    International Nuclear Information System (INIS)

    Jahangir, S.; Cheng, Xuan; Huang, H. H.; Nagarajan, V.; Ihlefeld, J.

    2014-01-01

    Solid state dewetting and the subsequent morphological changes for platinum thin films grown on zinc oxide (ZnO) buffered (001) silicon substrates (Pt/ZnO/SiO 2 /(001)Si system) is investigated under vacuum conditions via a custom-designed confocal laser microscope coupled with a laser heating system. Live imaging of thin film dewetting under a range of heating and quenching vacuum ambients reveals events including hillock formation, hole formation, and hole growth that lead to formation of a network of Pt ligaments, break up of Pt ligaments to individual islands and subsequent Pt islands shape reformation, in chronological fashion. These findings are corroborated by ex-situ materials characterization and quantitative electron microscopy analysis. A secondary hole formation via blistering before film rupture is revealed to be the critical stage, after which a rapid dewetting catastrophe occurs. This process is instantaneous and cannot be captured by ex-situ methods. Finally, an intermetallic phase forms at 900 °C and alters the morphology of Pt islands, suggesting a practical limit to the thermal environments that may be used for these platinized silicon wafers in vacuum conditions.

  13. Super-Penrose process due to collisions inside ergosphere

    Science.gov (United States)

    Zaslavskii, O. B.

    If two particles collide inside the ergosphere, the energy in the center of mass frame can be made unbound provided at least one of particles has a large negative angular momentum [A. A. Grib and Yu. V. Pavlov, Europhys. Lett. 101 (2013) 20004]. We show that the same condition can give rise to unbounded Killing energy of debris at infinity, i.e. super-Penrose process. Proximity of the point of collision to the black hole horizon is not required.

  14. Eyewitness Identification Reform: Data, Theory, and Due Process.

    Science.gov (United States)

    Clark, Steven E

    2012-05-01

    Some commentators view my analyses (Clark, 2012, this issue) as an important step forward in assessing the costs and benefits of eyewitness identification reform. Others suggest that the trade-off between correct identifications lost and false identifications avoided is well-known; that the expected utility model is misspecified; and that the loss of correct identifications due to the use of reformed eyewitness identification procedures is irrelevant to policy decisions, as those correct identifications are the illegitimate product of suggestion and lucky guesses. Contrary to these criticisms, the loss of correct identifications has not been adequately considered in theoretical or policy matters, criticisms regarding the various utilities do not substantively change the nature of the trade-off, and the dismissal of lost correct identifications is based not on data but on an outdated theory of recognition memory. © The Author(s) 2012.

  15. Thermal dewetting with a chemically heterogeneous nano-template for self-assembled L1(0) FePt nanoparticle arrays.

    Science.gov (United States)

    Wang, Liang-Wei; Cheng, Chung-Fu; Liao, Jung-Wei; Wang, Chiu-Yen; Wang, Ding-Shuo; Huang, Kuo-Feng; Lin, Tzu-Ying; Ho, Rong-Ming; Chen, Lih-Juann; Lai, Chih-Huang

    2016-02-21

    A design for the fabrication of metallic nanoparticles is presented by thermal dewetting with a chemically heterogeneous nano-template. For the template, we fabricate a nanostructured polystyrene-b-polydimethylsiloxane (PS-b-PDMS) film on a Si|SiO2 substrate, followed by a thermal annealing and reactive ion etching (RIE) process. This gives a template composed of an ordered hexagonal array of SiOC hemispheres emerging in the polystyrene matrix. After the deposition of a FePt film on this template, we utilize the rapid thermal annealing (RTA) process, which provides in-plane stress, to achieve thermal dewetting and structural ordering of FePt simultaneously. Since the template is composed of different composition surfaces with periodically varied morphologies, it offers more tuning knobs to manipulate the nanostructures. We show that both the decrease in the area of the PS matrix and the increase in the strain energy relaxation transfer the dewetted pattern from the randomly distributed nanoparticles into a hexagonal periodic array of L10 FePt nanoparticles. Transmission electron microscopy with the in situ heating stage reveals the evolution of the dewetting process, and confirms that the positions of nanoparticles are aligned with those of the SiOC hemispheres. The nanoparticles formed by this template-dewetting show an average diameter and center-to-center distance of 19.30 ± 2.09 nm and 39.85 ± 4.80 nm, respectively. The hexagonal array of FePt nanoparticles reveals a large coercivity of 1.5 T, much larger than the nanoparticles fabricated by top-down approaches. This approach offers an efficient pathway toward self-assembled nanostructures in a wide range of material systems.

  16. Selective modulation of nociceptive processing due to noise distraction.

    Science.gov (United States)

    Boyle, Yvonne; El-Deredy, Wael; Martínez Montes, Eduardo; Bentley, Deborah E; Jones, Anthony K P

    2008-09-15

    This study investigates the effects of noise distraction on the different components and sources of laser-evoked potentials (LEPs) whilst attending to either the spatial component (localisation performance task) or the affective component (unpleasantness rating task) of pain. LEPs elicited by CO2 laser stimulation of the right forearm were recorded from 64 electrodes in 18 consenting healthy volunteers. Subjects reported either pain location or unpleasantness, in the presence and absence of distraction by continuous 85 dBa white noise. Distributed sources of the LEP peaks were identified using Low Resolution Electromagnetic Tomography (LORETA). Pain unpleasantness ratings and P2 (430 ms) peak amplitude were significantly reduced by distraction during the unpleasantness task, whereas the localisation ability and the corresponding N1/N2 (310 ms) peak amplitude remained unchanged. Noise distraction (at 310 ms) reduced activation in the anterior cingulate cortex (ACC) and precuneus during attention to localisation and unpleasantness, respectively. This suggests a complimentary role for these two areas in the control of attention to pain. In contrast, activation of the occipital pole and SII were enhanced by noise during the localisation and unpleasantness task, respectively, suggesting that the presence of noise was associated with increased spatial attentional load. This study has shown selective modulation of affective pain processing by noise distraction, indicated by a reduction in the unpleasantness ratings and P2 peak amplitude and associated activity within the medial pain system. These results show that processing of the affective component of pain can be differentially modulated by top-down processes, providing a potential mechanism for therapeutic intervention.

  17. Controlling thin film structure for the dewetting of catalyst nanoparticle arrays for subsequent carbon nanofiber growth

    International Nuclear Information System (INIS)

    Randolph, S J; Fowlkes, J D; Melechko, A V; Klein, K L; III, H M Meyer; Simpson, M L; Rack, P D

    2007-01-01

    Vertically aligned carbon nanofiber (CNF) growth is a catalytic chemical vapor deposition process in which structure and functionality is controlled by the plasma conditions and the properties of the catalyst nanoparticles that template the fiber growth. We have found that the resultant catalyst nanoparticle network that forms by the dewetting of a continuous catalyst thin film is dependent on the initial properties of the thin film. Here we report the ability to tailor the crystallographic texture and composition of the nickel catalyst film and subsequently the nanoparticle template by varying the rf magnetron sputter deposition conditions. After sputtering the Ni catalyst thin films, the films are heated and exposed to an ammonia dc plasma, to chemically reduce the native oxide on the films and induce dewetting of the film to form nanoparticles. Subsequent nanoparticle treatment in an acetylene plasma at high substrate temperature results in CNF growth. Evidence is presented that the texture and composition of the nickel thin film has a significant impact on the structure and composition of the formed nanoparticle, as well as the resultant CNF morphology. Nickel films with a preferred (111) or (100) texture were produced and conditions favoring interfacial silicidation reactions were identified and investigated. Both compositional and structural analysis of the films and nanoparticles indicate that the properties of the as-deposited Ni catalyst film influences the subsequent nanoparticle formation and ultimately the catalytic growth of the carbon nanofibers

  18. Process Measurement Deviation Analysis for Flow Rate due to Miscalibration

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Eunsuk; Kim, Byung Rae; Jeong, Seog Hwan; Choi, Ji Hye; Shin, Yong Chul; Yun, Jae Hee [KEPCO Engineering and Construction Co., Deajeon (Korea, Republic of)

    2016-10-15

    An analysis was initiated to identify the root cause, and the exemption of high static line pressure correction to differential pressure (DP) transmitters was one of the major deviation factors. Also the miscalibrated DP transmitter range was identified as another major deviation factor. This paper presents considerations to be incorporated in the process flow measurement instrumentation calibration and the analysis results identified that the DP flow transmitter electrical output decreased by 3%. Thereafter, flow rate indication decreased by 1.9% resulting from the high static line pressure correction exemption and measurement range miscalibration. After re-calibration, the flow rate indication increased by 1.9%, which is consistent with the analysis result. This paper presents the brief calibration procedures for Rosemount DP flow transmitter, and analyzes possible three cases of measurement deviation including error and cause. Generally, the DP transmitter is required to be calibrated with precise process input range according to the calibration procedure provided for specific DP transmitter. Especially, in case of the DP transmitter installed in high static line pressure, it is important to correct the high static line pressure effect to avoid the inherent systematic error for Rosemount DP transmitter. Otherwise, failure to notice the correction may lead to indicating deviation from actual value.

  19. Pathways from disordered to ordered nanostructures from defect guided dewetting of ultrathin bilayers.

    Science.gov (United States)

    Hens, Abhiram; Mondal, Kartick; Biswas, Gautam; Bandyopadhyay, Dipankar

    2016-03-01

    Transitions from spinodal to pattern-guided dewetting of a bilayer of ultrathin films (dewetting to generate ordered patterns of nanoscopic size and periodicity. Comparing the results obtained from the MD simulations with the more widely employed continuum dynamics approach highlights the importance of the MD approach in quantitatively analyzing the dynamics of the dewetting of ultrathin films. The study demonstrates that the pattern-guided dewetting of confined bilayers can lead to ordered holes, droplets, and stripes with size and periodicity less than 10nm, which are yet to be realized experimentally and can be of significance for a number of future applications. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Promoting effect of ethanol on dewetting transition in the confined region of melittin tetramer

    International Nuclear Information System (INIS)

    Ren Xiuping; Zhou Bo; Wang Chunlei

    2012-01-01

    To study the influence of ethanol molecules on the melittin tetramer folding, we investigated the dewetting transition of the melittin tetramer immersed in pure water and 8% aqueous ethanol solution (mass fraction) by the molecular dynamics simulations. We found that the marked dewetting transitions occurred inside a nanoscale channel of the melittin tetramer both in pure water and in aqueous ethanol solution. Also, ethanol molecules promoted this dewetting transition. We attributed this promoting effect to ethanol molecules which prefer to locate at the liquid-vapor interface and decrease the liquid-vapor surface energy. The results provide insight into the effect of ethanol on the water dewetting phenomena. (authors)

  1. Bioplasmonic Alloyed Nanoislands Using Dewetting of Bilayer Thin Films.

    Science.gov (United States)

    Kang, Minhee; Ahn, Myeong-Su; Lee, Youngseop; Jeong, Ki-Hun

    2017-10-25

    Unlike monometallic materials, bimetallic plasmonic materials offer extensive benefits such as broadband tuning capability or high environmental stability. Here we report a broad range tuning of plasmon resonance of alloyed nanoislands by using solid-state dewetting of gold and silver bilayer thin films. Thermal dewetting after successive thermal evaporation of thin metal double-layer films readily forms AuAg-alloyed nanoislands with a precise composition ratio. The complete miscibility of alloyed nanoislands results in programmable tuning of plasmon resonance wavelength in a broadband visible range. Such extraordinary tuning capability opens up a new direction for plasmonic enhancement in biophotonic applications such as surface-enhanced Raman scattering or plasmon-enhanced fluorescence.

  2. Magnetic Iron Oxide Nanowires Formed by Reactive Dewetting.

    Science.gov (United States)

    Bennett, Roger A; Etman, Haitham A; Hicks, Hannah; Richards, Leah; Wu, Chen; Castell, Martin R; Dhesi, Sarnjeet S; Maccherozzi, Francesco

    2018-04-11

    The growth and reactive dewetting of ultrathin films of iron oxides supported on Re(0001) surfaces have been imaged in situ in real time. Initial growth forms a nonmagnetic stable FeO (wüstite like) layer in a commensurate network upon which high aspect ratio nanowires of several microns in length but less than 40 nm in width can be fabricated. The nanowires are closely aligned with the substrate crystallography and imaging by X-ray magnetic circular dichroism shows that each contain a single magnetic domain. The driving force for dewetting appears to be the minimization of strain energy of the Fe 3 O 4 crystallites and follows the Tersoff and Tromp model in which strain is minimized at constant height by extending in one epitaxially matched direction. Such wires are promising in spintronic applications and we predict that the growth will also occur on other hexagonal substrates.

  3. Solid-State Dewetting of Gold Aggregates/Islands on TiO2 Nanorod Structures Grown by Oblique Angle Deposition.

    Science.gov (United States)

    Liu, Shizhao; Plawsky, Joel L

    2017-12-12

    A composite film made of a stable gold nanoparticle (NP) array with well-controlled separation and size atop a TiO 2 nanorod film was fabricated via the oblique angle deposition (OAD) technique. The fabrication of the NP array is based on controlled, Rayleigh-instability-induced, solid-state dewetting of as-deposited gold aggregates on the TiO 2 nanorods. It was found that the initial spacing between as-deposited gold aggregates along the vapor flux direction should be greater than the TiO 2 interrod spacing created by 80° OAD to control dewetting and produce NP arrays. A numerical investigation of the process was conducted using a phase-field modeling approach. Simulation results showed that coalescence between neighboring gold aggregates is likely to have caused the uncontrolled dewetting in the 80° deposition, and this could be circumvented if the initial spacing between gold aggregates is larger than a critical value s min . We also found that TiO 2 nanorod tips affect dewetting dynamics differently than planar TiO 2 . The topology of the tips can induce contact line pinning and an increase in the contact angle along the vapor flux direction to the supported gold aggregates. These two effects are beneficial for the fabrication of monodisperse NPs based on Rayleigh-instability-governed self-assembly of materials, as they help to circumvent the undesired coalescence and facilitate the instability growth on the supported material. The findings uncover the application potential of OAD as a new method to fabricate structured films as template substrates to mediate dewetting. The reported composite films would have uses in optical coatings and photocatalytic systems, taking advantage of their ability to combine plasmonic nanostructures within a nanostructured dielectric film.

  4. Procedural Due Process and Fairness in Student Discipline. A Legal Memorandum.

    Science.gov (United States)

    Johnson, T. Page

    When the Supreme Court decided that the Constitution requires public school principals to follow procedural due process in suspension and expulsion cases, the Justices recognized a link between procedural due process and the fairness of effective discipline. This report reviews the constitutional due process required when public school officials…

  5. Water in contact with extended hydrophobic surfaces: Direct evidence of weak dewetting

    DEFF Research Database (Denmark)

    Jensen, Torben René; Jensen, Morten Østergaard; Reitzel, Niels

    2003-01-01

    X-ray reflectivity measurements reveal a significant dewetting of a large hydrophobic paraffin surface floating on water. The dewetting phenomenon extends less than 15 Angstrom into the bulk water phase and results in an integrated density deficit of about one water molecule per 25-30 Angstrom(2...

  6. Room-temperature deposition of crystalline patterned ZnO films by confined dewetting lithography

    Energy Technology Data Exchange (ETDEWEB)

    Sepulveda-Guzman, S., E-mail: selene.sepulvedagz@uanl.edu.mx [Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia. UANL, PIIT Monterrey, CP 66629, Apodaca NL (Mexico); Reeja-Jayan, B. [Texas Materials Institute, University of Texas at Austin, Austin, TX 78712 (United States); De la Rosa, E. [Centro de Investigacion en Optica, Loma del Bosque 115 Col. Lomas del Campestre C.P. 37150 Leon, Gto. Mexico (Mexico); Ortiz-Mendez, U. [Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia. UANL, PIIT Monterrey, CP 66629, Apodaca NL (Mexico); Reyes-Betanzo, C. [Instituto Nacional de Astrofisica Optica y Electronica, Calle Luis Enrique Erro No. 1, Santa Maria Tonanzintla, Puebla. Apdo. Postal 51 y 216, C.P. 72000 Puebla (Mexico); Cruz-Silva, R. [Centro de Investigacion en Ingenieria y Ciencias Aplicadas, UAEM. Av. Universidad 1001, Col. Chamilpa, CP 62210 Cuernavaca, Mor. (Mexico); Jose-Yacaman, M. [Physics and Astronomy Department University of Texas at San Antonio 1604 campus San Antonio, TX 78249 (United States)

    2010-03-15

    In this work patterned ZnO films were prepared at room-temperature by deposition of {approx}5 nm size ZnO nanoparticles using confined dewetting lithography, a process which induces their assembly, by drying a drop of ZnO colloidal dispersion between a floating template and the substrate. Crystalline ZnO nanoparticles exhibit a strong visible (525 nm) light emission upon UV excitation ({lambda} = 350 nm). The resulting films were characterized by scanning electron microscopy (SEM) and atomic force microscope (AFM). The method described herein presents a simple and low cost method to prepare crystalline ZnO films with geometric patterns without additional annealing. Such transparent conducting films are attractive for applications like light emitting diodes (LEDs). As the process is carried out at room temperature, the patterned crystalline ZnO films can even be deposited on flexible substrates.

  7. Room-temperature deposition of crystalline patterned ZnO films by confined dewetting lithography

    International Nuclear Information System (INIS)

    Sepulveda-Guzman, S.; Reeja-Jayan, B.; De la Rosa, E.; Ortiz-Mendez, U.; Reyes-Betanzo, C.; Cruz-Silva, R.; Jose-Yacaman, M.

    2010-01-01

    In this work patterned ZnO films were prepared at room-temperature by deposition of ∼5 nm size ZnO nanoparticles using confined dewetting lithography, a process which induces their assembly, by drying a drop of ZnO colloidal dispersion between a floating template and the substrate. Crystalline ZnO nanoparticles exhibit a strong visible (525 nm) light emission upon UV excitation (λ = 350 nm). The resulting films were characterized by scanning electron microscopy (SEM) and atomic force microscope (AFM). The method described herein presents a simple and low cost method to prepare crystalline ZnO films with geometric patterns without additional annealing. Such transparent conducting films are attractive for applications like light emitting diodes (LEDs). As the process is carried out at room temperature, the patterned crystalline ZnO films can even be deposited on flexible substrates.

  8. A dewetting route to grow heterostructured nanoparticles based on thin film heterojunctions.

    Science.gov (United States)

    Li, Junjie; Yin, Deqiang; Li, Qiang; Chen, Chunlin; Huang, Sumei; Wang, Zhongchang

    2015-12-21

    Heterostructured nanoparticles have received considerable attention for their various applications due to their unique and tunable functionalities with respect to their individual bulk constituents. However, the current wet chemical synthesis of multicomponent heterostructured nanoparticles is rather complicated. Here, we report a simple and quick method to fabricate Co-Au dumbbell arrays by dewetting Co/Au heterojunctions on a Si substrate and demonstrate that the Co-Au dumbbells vary in size from 2 to 28 nm. We further show by chemical mapping that Co bells are covered by a pseudomorphic Au wetting layer of ∼4 Å, preventing the bells from oxidation. By controlling the thickness of metal heterojunctions and the annealing time, the morphology of the Co-Au nanoparticle is found to be transformed from the dumbbell to the core shell. This facile route is demonstrated to be useful for fabricating other metal-metal and metal-oxide heterostructures and hence holds technological promise for functional applications.

  9. Complex dewetting scenarios of ultrathin silicon films for large-scale nanoarchitectures.

    Science.gov (United States)

    Naffouti, Meher; Backofen, Rainer; Salvalaglio, Marco; Bottein, Thomas; Lodari, Mario; Voigt, Axel; David, Thomas; Benkouider, Abdelmalek; Fraj, Ibtissem; Favre, Luc; Ronda, Antoine; Berbezier, Isabelle; Grosso, David; Abbarchi, Marco; Bollani, Monica

    2017-11-01

    Dewetting is a ubiquitous phenomenon in nature; many different thin films of organic and inorganic substances (such as liquids, polymers, metals, and semiconductors) share this shape instability driven by surface tension and mass transport. Via templated solid-state dewetting, we frame complex nanoarchitectures of monocrystalline silicon on insulator with unprecedented precision and reproducibility over large scales. Phase-field simulations reveal the dominant role of surface diffusion as a driving force for dewetting and provide a predictive tool to further engineer this hybrid top-down/bottom-up self-assembly method. Our results demonstrate that patches of thin monocrystalline films of metals and semiconductors share the same dewetting dynamics. We also prove the potential of our method by fabricating nanotransfer molding of metal oxide xerogels on silicon and glass substrates. This method allows the novel possibility of transferring these Si-based patterns on different materials, which do not usually undergo dewetting, offering great potential also for microfluidic or sensing applications.

  10. Efficient Photocatalytic H2 Evolution: Controlled Dewetting-Dealloying to Fabricate Site-Selective High-Activity Nanoporous Au Particles on Highly Ordered TiO2 Nanotube Arrays.

    Science.gov (United States)

    Nguyen, Nhat Truong; Altomare, Marco; Yoo, JeongEun; Schmuki, Patrik

    2015-05-27

    Anodic self-organized TiO2 nanostumps are formed and exploited for self-ordering dewetting of Au-Ag sputtered films. This forms ordered particle configurations at the tube top (crown position) or bottom (ground position). By dealloying from a minimal amount of noble metal, porous Au nanoparticles are then formed, which, when in the crown position, allow for a drastically improved photocatalytic H2 production compared with nanoparticles produced by conventional dewetting processes. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Due Process in the Realm of Higher Education: Considerations for Dealing with Students Rights

    Science.gov (United States)

    Fishner, Jason T.

    2006-01-01

    Court decisions have laid out expectations of what due process procedures need to be followed in student disciplinary cases and academic dismissal cases due to poor academic performance. This paper will give show where due process comes from and how it found its way into higher education. It will show that there are differences in the ways public…

  12. In situ observation of electron-beam-induced dewetting of CdSe thin film embedded in SiO2

    DEFF Research Database (Denmark)

    Fabrim, Zacarias Eduardo; Kjelstrup-Hansen, Jakob; Fichtner, Paulo F. P.

    In this work we show the dewetting process of the CdSe thin films induced by electron beam irradiation. A multilayer heterostructure of SiO2/CdSe/SiO2 was made by a magnetron sputtering process. A plan-view (PV) sample was irradiated with 200 kV electrons in the TEM with two current densities: 0.......33 A.cm2 and 1.0 A.cm2 and at 80 kV with 0.37 A.cm2. The dewetting of the CdSe film is inferred by a number of micrographs taken during the irradiation. The microstructural changes were analyzed under the assumption of being induced by ballistic collision effects in the absence of sample heating....

  13. Dewetting and Hydrophobic Interaction in Physical and Biological Systems

    Science.gov (United States)

    Berne, Bruce J.; Weeks, John D.; Zhou, Ruhong

    2013-01-01

    Hydrophobicity manifests itself differently on large and small length scales. This review focuses on large length scale hydrophobicity, particularly on dewetting at single hydrophobic surfaces and drying in regions bounded on two or more sides by hydrophobic surfaces. We review applicable theories, simulations and experiments pertaining to large scale hydrophobicity in physical and biomoleclar systems and clarify some of the critical issues pertaining to this subject. Given space constraints, we could not review all of the significant and interesting work in this very active field. PMID:18928403

  14. Dynamic Wetting and Dewetting: Comparison of Experiment with Theories

    Directory of Open Access Journals (Sweden)

    Orlova Evgeniya.G.

    2016-01-01

    Full Text Available The dynamics wetting/dewetting of a metal surface by distilled water drop was studied experimentally. The advancing and receding dynamic contact angles were obtained as a function of a contact line speed. The hydrodynamic and molecular-kinetic models have been applied to the experimental data to interpret the obtained results. The independent variables of the molecular-kinetic and hydrodynamic models, and the determination coefficient were determined by fitting procedure. The receding contact angles are found to be fitted better to the wetting models in comparison with the advancing dynamic contact angles.

  15. Dewetting at the edge of a thin NiO-film on Si by swift heavy ion irradiation

    International Nuclear Information System (INIS)

    Dautel, Knut; Ferhati, Redi; Bolse, Wolfgang

    2014-01-01

    We have investigated dewetting along a straight edge of a thin NiO-film on a Si-wafer induced by irradiation with 4.8 MeV/u Au-ions at room temperature. Both, the retreat of the edge as well as the opening and growth of circular holes in the film were monitored using our in-situ high resolution scanning electron microscope at the UNILAC accelerator at the Helmholtz Centre for Heavy Ion Research in Darmstadt. The “dewetting kinetics” (dependence of the retreated length and the hole radius on the ion fluence) are compared to previously published results on dewetting of poly-crystalline (Au) and glassy (polymer) films. In the present case the dewetting kinetics compare well with those observed for isothermal dewetting of the highly viscous polymer films, presumed that the role of time in thermally induced dewetting is taken over by the ion fluence in ion induced dewetting. Both, from the dewetting kinetics and the shape of the remaining NiO-traces in the dewetted area in front of the retreating edge, we conclude that the presently observed swift heavy ion induced dewetting occurs by interfacial slipping. It occurs in spatially and timely separated steps in the transiently molten single ion tracks, where the required reduction of the viscosity of NiO is achieved

  16. Dewetting at the edge of a thin NiO-film on Si by swift heavy ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Dautel, Knut; Ferhati, Redi; Bolse, Wolfgang, E-mail: w.bolse@ihfg.uni-stuttgart.de

    2014-01-01

    We have investigated dewetting along a straight edge of a thin NiO-film on a Si-wafer induced by irradiation with 4.8 MeV/u Au-ions at room temperature. Both, the retreat of the edge as well as the opening and growth of circular holes in the film were monitored using our in-situ high resolution scanning electron microscope at the UNILAC accelerator at the Helmholtz Centre for Heavy Ion Research in Darmstadt. The “dewetting kinetics” (dependence of the retreated length and the hole radius on the ion fluence) are compared to previously published results on dewetting of poly-crystalline (Au) and glassy (polymer) films. In the present case the dewetting kinetics compare well with those observed for isothermal dewetting of the highly viscous polymer films, presumed that the role of time in thermally induced dewetting is taken over by the ion fluence in ion induced dewetting. Both, from the dewetting kinetics and the shape of the remaining NiO-traces in the dewetted area in front of the retreating edge, we conclude that the presently observed swift heavy ion induced dewetting occurs by interfacial slipping. It occurs in spatially and timely separated steps in the transiently molten single ion tracks, where the required reduction of the viscosity of NiO is achieved.

  17. The Analytical Pragmatic Structure of Procedural Due Process: A Framework for Inquiry in Administrative Decision Making.

    Science.gov (United States)

    Fisher, James E.; Sealey, Ronald W.

    The study describes the analytical pragmatic structure of concepts and applies this structure to the legal concept of procedural due process. This structure consists of form, purpose, content, and function. The study conclusions indicate that the structure of the concept of procedural due process, or any legal concept, is not the same as the…

  18. 25 CFR 42.6 - When does due process require a formal disciplinary hearing?

    Science.gov (United States)

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false When does due process require a formal disciplinary... RIGHTS § 42.6 When does due process require a formal disciplinary hearing? Unless local school policies and procedures provide for less, a formal disciplinary hearing is required before a suspension in...

  19. Dewetting and deposition of thin films with insoluble surfactants from curved silicone hydrogel substrates.

    Science.gov (United States)

    Bhamla, M Saad; Balemans, Caroline; Fuller, Gerald G

    2015-07-01

    We investigate the stabilizing effect of insoluble surfactant monolayers on thin aqueous films. We first describe an experimental platform that enables the formation of aqueous films laden with dipalmitoylphosphatidylcholine (DPPC) monolayers on curved silicone hydrogel (SiHy) substrates. We show that these surfactant layers extend the lifetime of the aqueous films. The films eventually "dewet" by the nucleation and growth of dry areas and the onset of this dewetting can be controlled by the surface rheology of the DPPC layer. We thus demonstrate that increasing the interfacial rheology of the DPPC layer leads to stable films that delay dewetting. We also show that dewetting can be exploited to controllably pattern the underlying curved SiHy substrates with DPPC layers. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Transcellular tunnel dynamics: Control of cellular dewetting by actomyosin contractility and I-BAR proteins.

    Science.gov (United States)

    Lemichez, Emmanuel; Gonzalez-Rodriguez, David; Bassereau, Patricia; Brochard-Wyart, Françoise

    2013-03-01

    Dewetting is the spontaneous withdrawal of a liquid film from a non-wettable surface by nucleation and growth of dry patches. Two recent reports now propose that the principles of dewetting explain the physical phenomena underpinning the opening of transendothelial cell macroaperture (TEM) tunnels, referred to as cellular dewetting. This was discovered by studying a group of bacterial toxins endowed with the property of corrupting actomyosin cytoskeleton contractility. For both liquid and cellular dewetting, the growth of holes is governed by a competition between surface forces and line tension. We also discuss how the dynamics of TEM opening and closure represent remarkable systems to investigate actin cytoskeleton regulation by sensors of plasma membrane curvature and investigate the impact on membrane tension and the role of TEM in vascular dysfunctions. Copyright © 2013 Soçiété Française des Microscopies and Soçiété de Biologie Cellulaire de France.

  1. Lithography-Free Fabrication of Large Area Subwavelength Antireflection Structures Using Thermally Dewetted Pt/Pd Alloy Etch Mask

    Directory of Open Access Journals (Sweden)

    Kang Jeong-Jin

    2009-01-01

    Full Text Available Abstract We have demonstrated lithography-free, simple, and large area fabrication method for subwavelength antireflection structures (SAS to achieve low reflectance of silicon (Si surface. Thin film of Pt/Pd alloy on a Si substrate is melted and agglomerated into hemispheric nanodots by thermal dewetting process, and the array of the nanodots is used as etch mask for reactive ion etching (RIE to form SAS on the Si surface. Two critical parameters, the temperature of thermal dewetting processes and the duration of RIE, have been experimentally studied to achieve very low reflectance from SAS. All the SAS have well-tapered shapes that the refractive index may be changed continuously and monotonously in the direction of incident light. In the wavelength range from 350 to 1800 nm, the measured reflectance of the fabricated SAS averages out to 5%. Especially in the wavelength range from 550 to 650 nm, which falls within visible light, the measured reflectance is under 0.01%.

  2. Single-machine common/slack due window assignment problems with linear decreasing processing times

    Science.gov (United States)

    Zhang, Xingong; Lin, Win-Chin; Wu, Wen-Hsiang; Wu, Chin-Chia

    2017-08-01

    This paper studies linear non-increasing processing times and the common/slack due window assignment problems on a single machine, where the actual processing time of a job is a linear non-increasing function of its starting time. The aim is to minimize the sum of the earliness cost, tardiness cost, due window location and due window size. Some optimality results are discussed for the common/slack due window assignment problems and two O(n log n) time algorithms are presented to solve the two problems. Finally, two examples are provided to illustrate the correctness of the corresponding algorithms.

  3. Standard Setting as Psychometric Due Process: Going a Little Further Down an Uncertain Road.

    Science.gov (United States)

    Cizek, Gregory J.

    The concept of due process provides an analogy for the process of standard setting that emphasizes many of the procedural and substantive elements of the process over technical and statistical concerns. Surely such concerns can and should continue to be addressed. However, a sound rationale for standard setting does not rest on this foundation.…

  4. Water in contact with extended hydrophobic surfaces: Direct evidence of weak dewetting

    International Nuclear Information System (INIS)

    Jensen, Torben R.; Kjaer, Kristian; Oestergaard Jensen, Morten; Peters, Guenther H.; Reitzel, Niels; Balashev, Konstantin; Bjoernholm, Thomas

    2003-01-01

    X-ray reflectivity measurements reveal a significant dewetting of a large hydrophobic paraffin surface floating on water. The dewetting phenomenon extends less than 15 A into the bulk water phase and results in an integrated density deficit of about one water molecule per 25-30 A 2 of water in contact with the paraffin surface. The results are supported by molecular dynamics simulations and related to the hydrophobic effect

  5. Fabrication of metallic nanoparticles by spinodal dewetting of thin films: A high-throughput approach

    Energy Technology Data Exchange (ETDEWEB)

    Michalak, William D.; Miller, James B. [U.S. Department of Energy, National Energy Technology Laboratory, Pittsburgh, PA 15262 (United States); Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Yolcu, Cem [Department of Physics, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Gellman, Andrew J., E-mail: gellman@cmu.edu [U.S. Department of Energy, National Energy Technology Laboratory, Pittsburgh, PA 15262 (United States); Department of Chemical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213 (United States)

    2012-11-01

    Metal nanoparticles on structured supports are used in a variety of technological applications including biosensing, energy harvesting, and electronics. In every case, the functions and properties of the metallic nanostructures depend on both their composition and structure (i.e. size, shape, and spatial distribution). Among the challenges to the development of metal nanoparticles for these applications is the characterization of relationships between their structure and their functional properties over multiple structural degrees of freedom spanning a large range of values. In this work, a method for creating a morphological gradient of metal nanoparticles on a substrate is described. The approach, suited for high-throughput fabrication and characterization, is based on spinodal dewetting of a metallic thin film from its substrate. Through control of initial film thickness, anneal temperature, and anneal time, spinodal dewetting results in supported nanoparticles with well-defined and controlled structure. The approach is demonstrated through its application to preparation of Pd nanoparticles on a silicon nitride substrate. The morphologies of the particles were characterized by scanning electron and atomic force microscopies. Free energy-based stability and topological analyses were used to confirm the dewetting mechanism. In addition, the stability theory provides a connection to the thermophysical properties of the resulting nanoparticle array. The dewetting approach is general to any metal/support system and provides an alternative, inexpensive, and robust means to rapidly create metal nanostructures with control of morphology. It shows promise for large scale production of metal nanoparticles structures, as well as understanding basic stability properties of thin metal films. - Highlights: Black-Right-Pointing-Pointer Pd dewetting from SiN occurs by a spinodal dewetting mechanism. Black-Right-Pointing-Pointer Dewetting occurs at temperatures well below the

  6. Fabrication of metallic nanoparticles by spinodal dewetting of thin films: A high-throughput approach

    International Nuclear Information System (INIS)

    Michalak, William D.; Miller, James B.; Yolcu, Cem; Gellman, Andrew J.

    2012-01-01

    Metal nanoparticles on structured supports are used in a variety of technological applications including biosensing, energy harvesting, and electronics. In every case, the functions and properties of the metallic nanostructures depend on both their composition and structure (i.e. size, shape, and spatial distribution). Among the challenges to the development of metal nanoparticles for these applications is the characterization of relationships between their structure and their functional properties over multiple structural degrees of freedom spanning a large range of values. In this work, a method for creating a morphological gradient of metal nanoparticles on a substrate is described. The approach, suited for high-throughput fabrication and characterization, is based on spinodal dewetting of a metallic thin film from its substrate. Through control of initial film thickness, anneal temperature, and anneal time, spinodal dewetting results in supported nanoparticles with well-defined and controlled structure. The approach is demonstrated through its application to preparation of Pd nanoparticles on a silicon nitride substrate. The morphologies of the particles were characterized by scanning electron and atomic force microscopies. Free energy-based stability and topological analyses were used to confirm the dewetting mechanism. In addition, the stability theory provides a connection to the thermophysical properties of the resulting nanoparticle array. The dewetting approach is general to any metal/support system and provides an alternative, inexpensive, and robust means to rapidly create metal nanostructures with control of morphology. It shows promise for large scale production of metal nanoparticles structures, as well as understanding basic stability properties of thin metal films. - Highlights: ► Pd dewetting from SiN occurs by a spinodal dewetting mechanism. ► Dewetting occurs at temperatures well below the melting point of Pd. ► Spinodal dewetting allows

  7. Morphological evolution in dewetting polystyrene/polyhedral oligomeric silsesquioxane thin film bilayers.

    Science.gov (United States)

    Paul, Rituparna; Karabiyik, Ufuk; Swift, Michael C; Hottle, John R; Esker, Alan R

    2008-05-06

    Morphological evolution in dewetting thin film bilayers of polystyrene (PS) and a polyhedral oligomeric silsesquioxane (POSS), trisilanolphenyl-POSS (TPP), was studied as a function of annealing temperature and annealing time. The results demonstrate unique dewetting morphologies in PS/TPP bilayers at elevated temperatures that are significantly different from those typically observed in dewetting polymer/polymer bilayers. During temperature ramp studies by optical microscopy (OM) in the reflection mode, PS/TPP bilayers form cracks with a weak optical contrast at approximately 130 degrees C. The crack formation is attributed to tensile stresses within the upper TPP layer. The weak optical contrast of the cracks observed in the bilayers for annealing temperatures below approximately 160 degrees C is consistent with the cracking and dewetting of only the upper TPP layer from the underlying PS layer. The optical contrast of the morphological features is significantly enhanced at annealing temperatures of >160 degrees C. This observation suggests dewetting of both the upper TPP and the lower PS layers that results in the exposure of the silicon substrate. Upon annealing the PS/TPP bilayers at 200 degrees C in a temperature jump experiment, the upper TPP layer undergoes instantaneous cracking as observed by OM. These cracks in the upper TPP layer serve as nucleation sites for rapid dewetting and aggregation of the TPP layer, as revealed by OM and atomic force microscopy (AFM). X-ray photoelectron spectroscopy (XPS) results indicated that dewetting of the lower PS layer ensued for annealing times >5 min and progressed up to 90 min. For annealing times >90 min, OM, AFM, and XPS results revealed complete dewetting of both the layers with the formation of TPP encapsulated PS droplets.

  8. Dewetting of low-viscosity films at solid/liquid interfaces.

    Science.gov (United States)

    Péron, Nicolas; Brochard-Wyart, Françoise; Duval, Hervé

    2012-11-13

    We report new experimental results on the dewetting of a mercury film (A) intercalated between a glass slab and an external nonmiscible liquid phase (B) under conditions of a large equilibrium contact angle. The viscosity of the external phase, ηB, was varied over 7 orders of magnitude. We observe a transition between two regimes of dewetting at a threshold viscosity of η(B)* ≈ (ρ(A)e|S̃|)(1/2), where ρ(A) is the mercury density, e is the film thickness, and |S̃| is the effective spreading coefficient. For η(B) dewetting is constant and ruled by Culick’s law, V ≈ (|S̃|/(ρ(A)e))(1/2). Capillary waves were observed at high dewetting velocities: they are a signature of hydraulic shock. For η(B) > η(B)*, the regime is viscous. The dewetting velocity is constant and scales as V ≈ |S̃|/η(B) in the limit of large η(B). We interpret this regime by a balance between the surface energy released during dewetting and the viscous dissipation in the surrounding liquid.

  9. Thermally induced delay and reversal of liquid film dewetting on chemically patterned surfaces.

    Science.gov (United States)

    Kalpathy, Sreeram K; Francis, Lorraine F; Kumar, Satish

    2013-10-15

    A thin liquid film resting on a solid substrate that is heated or cooled from below experiences surface tension gradients, which lead to Marangoni flows. We explore the behavior of such a film on a chemically patterned substrate which drives film dewetting in order to determine how surface patterning and applied temperature gradients can be designed to influence the behavior of thin-film coatings. A nonlinear partial differential equation for the film height based on lubrication theory is solved numerically for a broad range of problem parameters. Uniform cooling of the substrate is found to significantly delay dewetting that is driven by wettability gradients. Uniform heating speeds up dewetting but can destroy the near-perfect templating imposed by the surface patterning. However, localized heating and cooling together can accelerate dewetting while maintaining templating quality. Localized heating and cooling can also be used to drive liquid onto areas that it would dewet from in the absence of heating. Overall, these results indicate that applied temperature gradients can significantly influence dewetting driven by surface patterning, and suggest strategies for the creation of spatially patterned thin-film coatings and flow control in microfluidic devices. Copyright © 2013 Elsevier Inc. All rights reserved.

  10. Transition from Spin Dewetting to continuous film in spin coating of Liquid Crystal 5CB.

    Science.gov (United States)

    Dhara, Palash; Bhandaru, Nandini; Das, Anuja; Mukherjee, Rabibrata

    2018-05-08

    Spin dewetting refers to spontaneous rupture of the dispensed solution layer during spin coating, resulting in isolated but periodic, regular sized domains of the solute and is pre-dominant when the solute concentration (C n ) is very low. In this article we report how the morphology of liquid crystal (LC) 5CB thin films coated on flat and patterned PMMA substrate transform from spin dewetted droplets to continuous films with increase in C n . We further show that within the spin dewetted regime, with gradual increase in the solute concentration, periodicity of the isotropic droplets (λ D ) as well as their mean diameter (d D ), gradually decreases, till the film becomes continuous at a critical concentration (C n *). Interestingly, the trend that λ D reduces with increase in C n is exact opposite to what is observed in thermal/solvent vapor induced dewetting of a thin film. The spin dewetted droplets exhibit transient Radial texture, in contrast to Schlieren texture observed in elongated threads and continuous films of 5CB, which remains in the Nematic phase at room temperature. Finally we show that by casting the film on a grating patterned substrate it becomes possible to align the spin dewetted droplets along the contours substrate patterns.

  11. Observation and optical implications of oil dewetting patterns in electrowetting displays

    International Nuclear Information System (INIS)

    Sun Bo; Heikenfeld, Jason

    2008-01-01

    Growth of surface instabilities leading to periodic oil patterns in electrowetting display pixels has been experimentally observed. In the electrowetting display pixels, an electrical potential ranging between 0 V and 80 V is applied among a water electrode, dielectric layers consisting of an oil film, fluoropolymer, Parylene C and a lower electrode. As predicted by spinodal dewetting theory, application of electromechanical pressure to the oil film causes the film to dewet into a periodic arrangement of oil droplets. The separation distance, or wavelength, for the dewetted oil droplets decreases with increasing voltage or with decreasing oil film thickness. Various test voltages of 20–80 V and oil thicknesses values of 3.3–8.9 µm were shown to experimentally generate dewetting wavelengths ranging from 10's to 100's of µm. An increased number of oil droplets inside the display pixel decreases the maximum display transmission or reflection proportional to the cube root of the number of droplets. This work therefore provides a means to further understand oil film dewetting in electrowetting display pixels and explains the implications of the dewetting pattern on display optical performance

  12. The due-diligence process of purchasing or buying into a dental practice.

    Science.gov (United States)

    Conner, Vincent L

    2003-01-01

    A due-diligence or evaluation process is necessary when assessing a practice purchase opportunity. The standards for assessing the investment remain the same whether the buyer is purchasing a practice outright or buying a co-ownership interest.

  13. Fabrication of highly oriented D03-Fe3Si nanocrystals by solid-state dewetting of Si ultrathin layer

    International Nuclear Information System (INIS)

    Naito, Muneyuki; Nakagawa, Tatsuhiko; Machida, Nobuya; Shigematsu, Toshihiko; Nakao, Motoi; Sudoh, Koichi

    2013-01-01

    In this paper, highly oriented nanocrystals of Fe 3 Si with a D0 3 structure are fabricated on SiO 2 using ultrathin Si on insulator substrate. First, (001) oriented Si nanocrystals are formed on the SiO 2 layer by solid state dewetting of the top Si layer. Then, Fe addition to the Si nanocrystals is performed by reactive deposition epitaxy and post-deposition annealing at 500 °C. The structures of the Fe–Si nanocrystals are analyzed by cross-sectional transmission electron microscopy and nanobeam electron diffraction. We observe that Fe 3 Si nanocrystals with D0 3 , B2, and A2 structures coexist on the 1-h post-annealed samples. Prolonged annealing at 500 °C is effective in obtaining Fe 3 Si nanocrystals with a D0 3 single phase, thereby promoting structural ordering in the nanocrystals. We discuss the formation process of the highly oriented D0 3 -Fe 3 Si nanocrystals on the basis of the atomistic structural information. - Highlights: • Highly oriented Fe–Si nanocrystals (NCs) are fabricated by reactive deposition. • Si NCs formed by solid state dewetting of Si thin layers are used as seed crystals. • The structures of Fe–Si NCs are analyzed by nanobeam electron diffraction. • Most of Fe–Si NCs possess the D0 3 structure after post-deposition annealing

  14. Synergism of Dewetting and Self-Wrinkling To Create Two-Dimensional Ordered Arrays of Functional Microspheres.

    Science.gov (United States)

    Han, Xue; Hou, Jing; Xie, Jixun; Yin, Jian; Tong, Yi; Lu, Conghua; Möhwald, Helmuth

    2016-06-29

    Here we report a simple, novel, yet robust nonlithographic method for the controlled fabrication of two-dimensional (2-D) ordered arrays of polyethylene glycol (PEG) microspheres. It is based on the synergistic combination of two bottom-up processes enabling periodic structure formation for the first time: dewetting and the mechanical wrinkle formation. The deterministic dewetting results from the hydrophilic polymer PEG on an incompatible polystyrene (PS) film bound to a polydimethylsiloxane (PDMS) substrate, which is directed both by a wrinkled template and by the template-directed in-situ self-wrinkling PS/PDMS substrate. Two strategies have been introduced to achieve synergism to enhance the 2-D ordering, i.e., employing 2-D in-situ self-wrinkling substrates and boundary conditions. As a result, we achieve highly ordered 2-D arrays of PEG microspheres with desired self-organized microstructures, such as the array location (e.g., selectively on the crest/in the valley of the wrinkles), diameter, spacing of the microspheres, and array direction. Additionally, the coordination of PEG with HAuCl4 is utilized to fabricate 2-D ordered arrays of functional PEG-HAuCl4 composite microspheres, which are further converted into different Au nanoparticle arrays. This simple versatile combined strategy could be extended to fabricate highly ordered 2-D arrays of other functional materials and achieve desirable properties and functionalities.

  15. Functional patterned coatings by thin polymer film dewetting.

    Science.gov (United States)

    Telford, Andrew M; Thickett, Stuart C; Neto, Chiara

    2017-12-01

    An approach for the fabrication of functional polymer surface coatings is introduced, where micro-scale structure and surface functionality are obtained by means of self-assembly mechanisms. We illustrate two main applications of micro-patterned polymer surfaces obtained through dewetting of bilayers of thin polymer films. By tuning the physical and chemical properties of the polymer bilayers, micro-patterned surface coatings could be produced that have applications both for the selective attachment and patterning of proteins and cells, with potential applications as biomaterials, and for the collection of water from the atmosphere. In all cases, the aim is to achieve functional coatings using approaches that are simple to realize, use low cost materials and are potentially scalable. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Generalized Harmonic Functions and the Dewetting of Thin Films

    International Nuclear Information System (INIS)

    Auchmuty, Giles; Kloucek, Petr

    2007-01-01

    This paper describes the solvability of Dirichlet problems for Laplace's equation when the boundary data is not smooth enough for the existence of a weak solution in H 1 Ω. Scales of spaces of harmonic functions and of boundary traces are defined and the solutions are characterized as limits of classical harmonic functions in special norms. The generalized harmonic functions, and their norms, are defined using series expansions involving harmonic Steklov eigenfunctions on the domain. It is shown that the usual trace operator has a continuous extension to an isometric isomorphism of specific spaces. This provides a characterization of the generalized solutions of harmonic Dirichlet problems. Numerical simulations of a model problem are described. This problem is related to the dewetting of thin films and the associated phenomenology is described

  17. Constituents’ formal participation in the IASB’s due process: New insights into the impact of country and due process document characteristics

    Directory of Open Access Journals (Sweden)

    Michael Dobler

    2016-09-01

    Full Text Available This paper adopts a multi-issue/multi-period approach to provide new insights into key determinants of constituents’ formal participation in the due process of the International Accounting Standards Board (IASB. Based on an analysis of 8,825 comment letters submitted during the period 2006–2012, we find imbalances in the representation of constituents. Multiple regressions reveal that among various economic and cultural variables equity market capitalization and the society’s level of individualism are the key drivers of the country-level of constituents’ participation, and each variable has explanatory power over the other. The level of constituents’ participation is positively associated with the number of input opportunities offered by a due process document but unrelated to the complexity of a standard-setting project. The results are robust across various sub-samples and to additional sensitivity tests. Our findings indicate threats to the input legitimacy of the IASB and suggest avenues to stimulate constituents’ participation.

  18. Dewetting transition assisted clearance of (NFGAILS) amyloid fibrils from cell membranes by graphene

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Jiajia; Yang, Zaixing; Gu, Zonglin [Institute of Quantitative Biology and Medicine, SRMP and RAD-X, Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, and Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Soochow University, Suzhou 215123 (China); Li, Haotian [Bio-X Lab, Department of Physics, Zhejiang University, Hangzhou 310027 (China); Garate, Jose Antonio [IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Zhou, Ruhong, E-mail: ruhongz@us.ibm.com [Institute of Quantitative Biology and Medicine, SRMP and RAD-X, Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, and Jiangsu Provincial Key Laboratory of Radiation Medicine and Protection, Soochow University, Suzhou 215123 (China); IBM Thomas J. Watson Research Center, Yorktown Heights, New York 10598 (United States); Department of Chemistry, Columbia University, New York, New York 10027 (United States)

    2014-12-14

    Clearance of partially ordered oligomers and monomers deposited on cell membrane surfaces is believed to be an effective route to alleviate many potential protein conformational diseases (PCDs). With large-scale all-atom molecular dynamics simulations, here we show that graphene nanosheets can easily and quickly win a competitive adsorption of human islet amyloid polypeptides (hIAPP{sub 22-28}) NFGAILS and associated fibrils against cell membrane, due to graphene's unique two-dimensional, highly hydrophobic surface with its all-sp{sup 2} hybrid structure. A nanoscale dewetting transition was observed at the interfacial region between the fibril (originally deposited on the membrane) and the graphene nanosheet, which significantly assisted the adsorption of fibrils onto graphene from the membrane. The π–π stacking interaction between Phe23 and graphene played a crucial role, providing the driving force for the adsorption at the graphene surface. This study renders new insight towards the importance of water during the interactions between amyloid peptides, the phospholipidic membrane, and graphene, which might shed some light on future developments of graphene-based nanomedicine for preventing/curing PCDs like type II diabetes mellitus.

  19. Cross-sectional characterization of the dewetting of a Au/Ni bilayer film.

    Science.gov (United States)

    Cen, Xi; Thron, Andrew M; Zhang, Xinming; van Benthem, Klaus

    2017-07-01

    The solid state dewetting of Au/Ni bilayer films was investigated by cross-sectional transmission electron microscopy techniques, including energy-dispersive X-ray spectroscopy, electron energy-loss spectroscopy and precession electron diffraction. After annealing under high vacuum conditions the early stage of film agglomeration revealed significant changes in film morphology and chemical distribution. Both Au and Ni showed texturing. Despite the initial deposition sequence of the as-deposited Au/Ni/SiO 2 /Si interface structure, the majority of the metal/SiO 2 interface was Au/SiO 2 after annealing at 675°C for 1h. Void nucleation was predominantly observed at Au/Ni/SiO 2 triple junctions, rather than grain boundary grooving at free surface of the metal film. Detailed cross-sectional characterization reveals that the Au/Ni interface in addition to small amounts of metal alloying strongly affects film break-up and agglomeration kinetics. The formation of Au/SiO 2 interface sections is found to be energetically preferred over Ni/SiO 2 due to compressive stress in the as-deposited Ni layer. Void nucleation is observed at the film/substrate interface, while the formation of voids at Ni/Au phase boundaries inside the metal film is caused by the Kirkendall effect. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. Dewetting transition assisted clearance of (NFGAILS) amyloid fibrils from cell membranes by graphene

    International Nuclear Information System (INIS)

    Liu, Jiajia; Yang, Zaixing; Gu, Zonglin; Li, Haotian; Garate, Jose Antonio; Zhou, Ruhong

    2014-01-01

    Clearance of partially ordered oligomers and monomers deposited on cell membrane surfaces is believed to be an effective route to alleviate many potential protein conformational diseases (PCDs). With large-scale all-atom molecular dynamics simulations, here we show that graphene nanosheets can easily and quickly win a competitive adsorption of human islet amyloid polypeptides (hIAPP 22-28 ) NFGAILS and associated fibrils against cell membrane, due to graphene's unique two-dimensional, highly hydrophobic surface with its all-sp 2 hybrid structure. A nanoscale dewetting transition was observed at the interfacial region between the fibril (originally deposited on the membrane) and the graphene nanosheet, which significantly assisted the adsorption of fibrils onto graphene from the membrane. The π–π stacking interaction between Phe23 and graphene played a crucial role, providing the driving force for the adsorption at the graphene surface. This study renders new insight towards the importance of water during the interactions between amyloid peptides, the phospholipidic membrane, and graphene, which might shed some light on future developments of graphene-based nanomedicine for preventing/curing PCDs like type II diabetes mellitus

  1. Dewetting of thin liquid films on chemically patterned substrates : front propatation along narrow lyophobic stripes and stripe arrays

    NARCIS (Netherlands)

    Brasjen, B.J.; Gu, H.; Darhuber, A.A.

    2013-01-01

    Using experiments and numerical simulations, we investigate the dewetting of thin liquid films on chemically patterned substrates. The patterns consist of long and narrow hydrophobic stripes, separated by larger hydrophilic domains. We characterize the morphology and dynamics of the dewetting front

  2. Thermal dewetting behavior of polystyrene composite thin films with organic-modified inorganic nanoparticles.

    Science.gov (United States)

    Kubo, Masaki; Takahashi, Yosuke; Fujii, Takeshi; Liu, Yang; Sugioka, Ken-ichi; Tsukada, Takao; Minami, Kimitaka; Adschiri, Tadafumi

    2014-07-29

    The thermal dewetting of polystyrene composite thin films with oleic acid-modified CeO2 nanoparticles prepared by the supercritical hydrothermal synthesis method was investigated, varying the nanoparticle concentration (0-30 wt %), film thickness (approximately 50 and 100 nm), and surface energy of silanized silicon substrates on which the composite films were coated. The dewetting behavior of the composite thin films during thermal annealing was observed by an optical microscope. The presence of nanoparticles in the films affected the morphology of dewetting holes, and moreover suppressed the dewetting itself when the concentration was relatively high. It was revealed that there was a critical value of the surface energy of the substrate at which the dewetting occurred. In addition, the spatial distributions of nanoparticles in the composite thin films before thermal annealing were investigated using AFM and TEM. As a result, we found that most of nanoparticles segregated to the surface of the film, and that such distributions of nanoparticles contribute to the stabilization of the films, by calculating the interfacial potential of the films with nanoparticles.

  3. Gold nanoparticle array formation on dimpled Ta templates using pulsed laser-induced thin film dewetting.

    Science.gov (United States)

    El-Sayed, Hany A; Horwood, Corie A; Owusu-Ansah, Ebenezer; Shi, Yujun J; Birss, Viola I

    2015-04-28

    Here we show that pulsed laser-induced dewetting (PLiD) of a thin Au metallic film on a nano-scale ordered dimpled tantalum (DT) surface results in the formation of a high quality Au nanoparticle (NP) array. In contrast to thermal dewetting, PLiD does not result in deformation of the substrate, even when the Au film is heated to above its melting point. PLiD causes local heating of only the metal film and thus thermal oxidation of the Ta substrate can be avoided, also because of the high vacuum (low pO2) environment employed. Therefore, this technique can potentially be used to fabricate NP arrays composed of high melting point metals, such as Pt, not previously possible using conventional thermal annealing methods. We also show that the Au NPs formed by PLiD are more spherical in shape than those formed by thermal dewetting, likely demonstrating a different dewetting mechanism in the two cases. As the metallic NPs formed on DT templates are electrochemically addressable, a longer-term objective of this work is to determine the effect of NP size and shape (formed by laser vs. thermal dewetting) on their electrocatalytic properties.

  4. High-speed nanoscale characterization of dewetting via dynamic transmission electron microscopy

    International Nuclear Information System (INIS)

    Hihath, Sahar; Santala, Melissa K.; Campbell, Geoffrey; Benthem, Klaus van

    2016-01-01

    The dewetting of thin films can occur in either the solid or the liquid state for which different mass transport mechanisms are expected to control morphological changes. Traditionally, dewetting dynamics have been examined on time scales between several seconds to hours, and length scales ranging between nanometers and millimeters. The determination of mass transport mechanisms on the nanoscale, however, requires nanoscale spatial resolution and much shorter time scales. This study reports the high-speed observation of dewetting phenomena for kinetically constrained Ni thin films on crystalline SrTiO_3 substrates. Movie-mode Dynamic Transmission Electron Microscopy (DTEM) was used for high-speed image acquisition during thin film dewetting at different temperatures. DTEM imaging confirmed that the initial stages of film agglomeration include edge retraction, hole formation, and growth. Finite element modeling was used to simulate temperature distributions within the DTEM samples after laser irradiation with different energies. For pulsed laser irradiation at 18 μJ, experimentally observed hole growth suggests that Marangoni flow dominates hole formation in the liquid nickel film. After irradiation with 13.8 μJ, however, the observations suggest that dewetting was initiated by nucleation of voids followed by hole growth through solid-state surface diffusion.

  5. High-speed nanoscale characterization of dewetting via dynamic transmission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Hihath, Sahar [Department of Materials Science and Engineering, University of California, Davis, 1 Shields Ave., Davis, California 95616 (United States); Department of Physics, University of California, Davis, 1 Shields Ave., Davis, California 95616 (United States); Santala, Melissa K.; Campbell, Geoffrey [Materials Science Division, Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, California 94550 (United States); Benthem, Klaus van, E-mail: benthem@ucdavis.edu [Department of Materials Science and Engineering, University of California, Davis, 1 Shields Ave., Davis, California 95616 (United States)

    2016-08-28

    The dewetting of thin films can occur in either the solid or the liquid state for which different mass transport mechanisms are expected to control morphological changes. Traditionally, dewetting dynamics have been examined on time scales between several seconds to hours, and length scales ranging between nanometers and millimeters. The determination of mass transport mechanisms on the nanoscale, however, requires nanoscale spatial resolution and much shorter time scales. This study reports the high-speed observation of dewetting phenomena for kinetically constrained Ni thin films on crystalline SrTiO{sub 3} substrates. Movie-mode Dynamic Transmission Electron Microscopy (DTEM) was used for high-speed image acquisition during thin film dewetting at different temperatures. DTEM imaging confirmed that the initial stages of film agglomeration include edge retraction, hole formation, and growth. Finite element modeling was used to simulate temperature distributions within the DTEM samples after laser irradiation with different energies. For pulsed laser irradiation at 18 μJ, experimentally observed hole growth suggests that Marangoni flow dominates hole formation in the liquid nickel film. After irradiation with 13.8 μJ, however, the observations suggest that dewetting was initiated by nucleation of voids followed by hole growth through solid-state surface diffusion.

  6. Due Process in the Internet Jurisdiction: Landing Softly on the Other Side of the Looking Glass

    National Research Council Canada - National Science Library

    Kolb, Natalie A

    2001-01-01

    .... However, even if a U.S. state court exercises improper jurisdiction over a non-resident defendant in an Internet case, due process protection can be revived at the choice-of-law and enforcement stages of the judicial proceeding...

  7. A Longitudinal Study of Special Education Due Process Hearings in Massachusetts

    Directory of Open Access Journals (Sweden)

    William H. Blackwell

    2015-03-01

    Full Text Available Of the three formal dispute resolution procedures provided by the Individuals With Disabilities Education Act of 2004(IDEA, due process hearings are the most costly in terms of time, fiscal resources, and impact on relationships between school personnel and parents. This study examined 258 due process hearings held over the past 8 years in Massachusetts to examine the characteristics of students at the center of these disputes, the issues that were addressed in the hearings, and the representation utilized by parents and school districts. The findings from this study indicated that (a Massachusetts school districts utilized attorney representation and won due process hearings at notably higher levels than parents, and (b the most frequently addressed issues at due process hearings were Individualized Education Program (IEP development/implementation and educational program placement, which are issues that represent the core mandate of IDEA to provide a free appropriate public education in the least restrictive environment (34 C.F.R. §300.300, 300.550. The authors present recommendations for policy actions and areas for future research.

  8. Effects of surveillance on the rule of law, due process and the presumption of innocence

    NARCIS (Netherlands)

    Galetta, Antonella; de Hert, Paul; Wright, D.; Kreissl, R.

    2015-01-01

    This contribution focuses on the impact of surveillance on the rule of law, due process and the presumption of innocence, key values and principles of a democratic order. It illustrates how they are implemented and enforced in contemporary surveillance societies, while referring to European law and

  9. Due Process and Higher Education: A Systemic Approach to Fair Decision Making. ERIC Digest.

    Science.gov (United States)

    Stevens, Ed

    University officials and faculty are frequently required to make decisions based on interpretations of disputed facts. By applying the concept of due process within the context of higher education, they can meet legal challenges of contract and constitutional law and the pedagogical demand for justice. To guide their efforts, decision makers can…

  10. The Procedural Queer: Substantive Due Process, "Lawrence v. Texas," and Queer Rhetorical Futures

    Science.gov (United States)

    Campbell, Peter Odell

    2012-01-01

    This essay discusses Justice Anthony M. Kennedy's choice to foreground arguments from due process rather than equal protection in the majority opinion in Lawrence v. Texas. Kennedy's choice can realize constitutional legal doctrine that is more consistent with radical queer politics than arguments from equal protection. Unlike some recent…

  11. Formal participation in the IASB's due process of standard setting : A multi-issue/multiperiod analysis

    NARCIS (Netherlands)

    Jorissen, A.; Lybaert, N.; Orens, R.; van der Tas, L.G.

    2012-01-01

    This paper sets out to enquire about the nature of constituents' participation in the IASB's due process in terms of representation (constituents' diversity and characteristics) and drivers to participate. We choose to adopt a multi-issue/multi-period approach to investigate constituents' formal

  12. Au nanoparticles decorated SiO{sub 2} nanowires by dewetting on curved surfaces: facile synthesis and nanoparticles-nanowires sizes correlation

    Energy Technology Data Exchange (ETDEWEB)

    Ruffino, F., E-mail: francesco.ruffino@ct.infn.it; Grimaldi, M. G. [Universita di Catania, Dipartimento di Fisica e Astronomia (Italy)

    2013-09-15

    We report a solid-state synthesis for SiO{sub 2} nanowires (NWs) (up to 20 microns in length and from about 40 to about 150 nm in diameter) coated by Au nanoparticles (NPs) (from about 20 to about 80 nm in diameter). This protocol is based on three steps: (1) large area production of very long SiO{sub 2} NWs on a Si surface exploiting a simple Au/Si solid-state reaction at high temperature; (2) coating of the SiO{sub 2} NWs by a Au film of desired thickness using sputtering depositions; and (3) a thermal process to induce a dewetting process of the Au-film coating the SiO{sub 2} NWs to obtain Au NPs on the curved surface of the NWs. The morphology evolution of the SiO{sub 2} NWs was followed, in each step, by scanning electron microscopy analyses. They allowed to correlate the evolution of the NPs size with the NWs sizes for different thicknesses of the starting Au-film coating the NWs and different annealing temperatures of the dewetting process. Some theoretical concepts, related to the dewetting process of a film on a curved surface were used to describe the experimental data. The main advantages of the proposed protocols include: (i) simplicity and low-cost (it is based only on sputtering depositions and thermal processes), and (ii) versatility based on the possibility of tuning Au-film thickness and annealing temperature to tune the NPs-NWs sizes ratio. These advantages can make this technique suitable for the mass production of Au NPs-coated SiO{sub 2} NWs toward applications in electronic devices, biosensors, and nanoscale optical devices.

  13. Au nanoparticles decorated SiO2 nanowires by dewetting on curved surfaces: facile synthesis and nanoparticles–nanowires sizes correlation

    International Nuclear Information System (INIS)

    Ruffino, F.; Grimaldi, M. G.

    2013-01-01

    We report a solid-state synthesis for SiO 2 nanowires (NWs) (up to 20 microns in length and from about 40 to about 150 nm in diameter) coated by Au nanoparticles (NPs) (from about 20 to about 80 nm in diameter). This protocol is based on three steps: (1) large area production of very long SiO 2 NWs on a Si surface exploiting a simple Au/Si solid-state reaction at high temperature; (2) coating of the SiO 2 NWs by a Au film of desired thickness using sputtering depositions; and (3) a thermal process to induce a dewetting process of the Au-film coating the SiO 2 NWs to obtain Au NPs on the curved surface of the NWs. The morphology evolution of the SiO 2 NWs was followed, in each step, by scanning electron microscopy analyses. They allowed to correlate the evolution of the NPs size with the NWs sizes for different thicknesses of the starting Au-film coating the NWs and different annealing temperatures of the dewetting process. Some theoretical concepts, related to the dewetting process of a film on a curved surface were used to describe the experimental data. The main advantages of the proposed protocols include: (i) simplicity and low-cost (it is based only on sputtering depositions and thermal processes), and (ii) versatility based on the possibility of tuning Au-film thickness and annealing temperature to tune the NPs–NWs sizes ratio. These advantages can make this technique suitable for the mass production of Au NPs-coated SiO 2 NWs toward applications in electronic devices, biosensors, and nanoscale optical devices

  14. Sequence control of phase separation and dewetting in PS/PVME blend thin films by changing molecular weight of PS.

    Science.gov (United States)

    Xia, Tian; Qin, Yaping; Huang, Yajiang; Huang, Ting; Xu, Jianhui; Li, Youbing

    2016-11-28

    The morphology evolution mechanism of polystyrene (PS)/poly (vinyl methyl ether) (PVME) blend thin films with different PS molecular weights (M w ) was studied. It was found that the morphology evolution was closely related to the molecular weight asymmetry between PS and PVME. In the film where M w (PS) ≈ M w (PVME), dewetting happened at the interface between the bottom layer and substrate after SD phase separation. While in the film where M w (PS) > M w (PVME), dewetting happened at the interface between the middle PS/PVME blend layer and bottom PVME layer near the substrate prior to phase separation. The different sequences of phase separation and dewetting and different interface for dewetting occurrence were studied by regarding the competitive effects of viscoelasticity contrast between polymer components and preferential wetting between PVME and the substrate. The viscoelastic nature of the PS component played a crucial role in the sequence of phase separation and dewetting.

  15. Static or breakloose friction for lubricated contacts: the role of surface roughness and dewetting

    International Nuclear Information System (INIS)

    Lorenz, B; Persson, B N J; Krick, B A; Sawyer, W G; Rodriguez, N; Mangiagalli, P

    2013-01-01

    We present experimental data for the static or breakloose friction for lubricated elastomer contacts, as a function of the time of stationary contact. Due to fluid squeeze-out from the asperity contact regions, the breakloose friction force increases continuously with the time of stationary contact. We consider three different cases: (a) PDMS rubber balls against flat smooth glass surfaces, (b) PDMS cylinder ribs against different substrates (glass, smooth and rough PMMA and an inert polymer) and (c) application to syringes. Due to differences in the surface roughness and contact pressures the three systems exhibit very different time dependences of the breakloose friction. In case (a) for rough surfaces the dry contact area A is a small fraction of the nominal contact area A 0 , and the fluid squeeze-out is fast. In case (b) the dry contact area is close to the nominal contact area, A/A 0 ≈ 1, and fluid squeeze-out is very slow due to percolation of the contact area. In this case, remarkably, different fluids with very different viscosities, ranging from 0.005 Pa s (water–glycerol mixture) to 1.48 Pa s (glycerol), give very similar breakloose friction forces as a function of the time of stationary contact. In case (c) the contact pressure and the surface roughness are larger than in case (b), and the squeeze-out is very slow so that even after a very long time the area of real contact is below the percolation threshold. For all cases (a)–(c), the increase in the breakloose friction is mainly due to the increase in the area of real contact with increasing time, because of the fluid squeeze-out and dewetting. (paper)

  16. Static or breakloose friction for lubricated contacts: the role of surface roughness and dewetting.

    Science.gov (United States)

    Lorenz, B; Krick, B A; Rodriguez, N; Sawyer, W G; Mangiagalli, P; Persson, B N J

    2013-11-06

    We present experimental data for the static or breakloose friction for lubricated elastomer contacts, as a function of the time of stationary contact. Due to fluid squeeze-out from the asperity contact regions, the breakloose friction force increases continuously with the time of stationary contact. We consider three different cases: (a) PDMS rubber balls against flat smooth glass surfaces, (b) PDMS cylinder ribs against different substrates (glass, smooth and rough PMMA and an inert polymer) and (c) application to syringes. Due to differences in the surface roughness and contact pressures the three systems exhibit very different time dependences of the breakloose friction. In case (a) for rough surfaces the dry contact area A is a small fraction of the nominal contact area A0, and the fluid squeeze-out is fast. In case (b) the dry contact area is close to the nominal contact area, A/A0 ≈ 1, and fluid squeeze-out is very slow due to percolation of the contact area. In this case, remarkably, different fluids with very different viscosities, ranging from 0.005 Pa s (water–glycerol mixture) to 1.48 Pa s (glycerol), give very similar breakloose friction forces as a function of the time of stationary contact. In case (c) the contact pressure and the surface roughness are larger than in case (b), and the squeeze-out is very slow so that even after a very long time the area of real contact is below the percolation threshold. For all cases (a)–(c), the increase in the breakloose friction is mainly due to the increase in the area of real contact with increasing time, because of the fluid squeeze-out and dewetting.

  17. Stability and dewetting of metal nanoparticle filled thin polymer films: control of instability length scale and dynamics.

    Science.gov (United States)

    Mukherjee, Rabibrata; Das, Soma; Das, Anindya; Sharma, Satinder K; Raychaudhuri, Arup K; Sharma, Ashutosh

    2010-07-27

    We investigate the influence of gold nanoparticle addition on the stability, dewetting, and pattern formation in ultrathin polymer-nanoparticle (NP) composite films by examining the length and time scales of instability, morphology, and dynamics of dewetting. For these 10-50 nm thick (h) polystyrene (PS) thin films containing uncapped gold nanoparticles (diameter approximately 3-4 nm), transitions from complete dewetting to arrested dewetting to absolute stability were observed depending on the concentration of the particles. Experiments show the existence of three distinct stability regimes: regime 1, complete dewetting leading to droplet formation for nanoparticle concentration of 2% (w/w) or below; regime 2, partial dewetting leading to formation of arrested holes for NP concentrations in the range of 3-6%; and regime 3, complete inhibition of dewetting for NP concentrations of 7% and above. Major results are (a) length scale of instability, where lambdaH approximately hn remains unchanged with NP concentration in regime 1 (n approximately 2) but increases in regime 2 with a change in the scaling relation (n approximately 3-3.5); (b) dynamics of instability and dewetting becomes progressively sluggish with an increase in the NP concentration; (c) there are distinct regimes of dewetting velocity at low NP concentrations; (d) force modulation AFM, as well as micro-Raman analysis, shows phase separation and aggregation of the gold nanoparticles within each dewetted polymer droplet leading to the formation of a metal core-polymer shell morphology. The polymer shell could be removed by washing in a selective solvent, thus exposing an array of bare gold nanoparticle aggregates.

  18. Dewetting based fabrication of fibrous micro-scaffolds as potential injectable cell carriers.

    Science.gov (United States)

    Song, Hokyung; Yin, Liya; Chilian, William M; Zhang Newby, Bi-Min

    2015-03-01

    Although regenerative medicine utilizing tissue scaffolds has made enormous strides in recent years, many constraints still hamper their effectiveness. A limitation of many scaffolds is that they form surface patches, which are not particularly effective for some types of "wounds" that are deep within tissues, e.g., stroke and myocardial infarction. In this study, we reported the generation of fibrous micro-scaffolds feasible for delivering cells by injection into the tissue parenchyma. The micro-scaffolds (widthsdewetting of poly(lactic-co-glycolic acid) thin films containing parallel strips, and cells were seeded to form cell/polymer micro-constructs during or post the micro-scaffold fabrication process. Five types of cells including rat induced vascular progenitor cells were assessed for the formation of the micro-constructs. Critical factors in forming fibrous micro-scaffolds via dewetting of polymer thin films were found to be properties of polymers and supporting substrates, temperature, and proteins in the culture medium. Also, the ability of cells to attach to the micro-scaffolds was essential in forming cell/polymer micro-constructs. Both in vitro and in vivo assessments of injecting these micro-scaffolding constructs showed, as compared to free cells, enhanced cell retention at the injected site, which could lead to improved tissue engineering and regeneration. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. Nanostructure Formation by controlled dewetting on patterned substrates: A combined theoretical, modeling and experimental study.

    Science.gov (United States)

    Lu, Liang-Xing; Wang, Ying-Min; Srinivasan, Bharathi Madurai; Asbahi, Mohamed; Yang, Joel K W; Zhang, Yong-Wei

    2016-09-01

    We perform systematic two-dimensional energetic analysis to study the stability of various nanostructures formed by dewetting solid films deposited on patterned substrates. Our analytical results show that by controlling system parameters such as the substrate surface pattern, film thickness and wetting angle, a variety of equilibrium nanostructures can be obtained. Phase diagrams are presented to show the complex relations between these system parameters and various nanostructure morphologies. We further carry out both phase field simulations and dewetting experiments to validate the analytically derived phase diagrams. Good agreements between the results from our energetic analyses and those from our phase field simulations and experiments verify our analysis. Hence, the phase diagrams presented here provide guidelines for using solid-state dewetting as a tool to achieve various nanostructures.

  20. Local nanostructuring of gold thin films through dewetting induced by Ga{sup +} irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Lo Savio, R., E-mail: roberto.lo.savio@edu.unige.it [Physics Department and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Repetto, L. [Physics Department and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy); Šetina Batič, B. [Inštitut Za Kovinske Materiale in Tehnologije, Lepi pot 11, 1000 Ljubljana (Slovenia); Firpo, G.; Valbusa, U. [Physics Department and Nanomed Labs, Università di Genova, Via Dodecaneso 33, 16146 Genova (Italy)

    2015-07-01

    Dewetting of ion-irradiated metal films is a consequence of the local melting occurring during the irradiation. In this study we present the dewetting evolution of Au thin films bombarded with Ga{sup +} ions in a focused ion beam system, pointing out the different surface patterns observed in films having different starting thickness and morphology. In fact, in ion-irradiated films thicker than 2 nm the typical features of dewetted liquids appear, i.e. enlarging dry holes surrounded by metal interconnections. On the other side, a different behavior is observed in thinner discontinuous films, where a dense distribution of circular nanoparticles is formed upon irradiation. We studied the dependence of Au nanoparticles distribution obtained for different ion energies and fluences, determining that a maximum fluence of ∼2 × 10{sup 14} Ga/cm{sup 2} can be used to achieve a monomodal distribution of nanoparticles with regular shape, before detrimental effects of sputtering occur.

  1. Dynamics of the evaporative dewetting of a volatile liquid film confined within a circular ring.

    Science.gov (United States)

    Sun, Wei; Yang, Fuqian

    2015-04-07

    The dewetting dynamics of a toluene film confined within a copper ring on a deformable PMMA film is studied. The toluene film experiences evaporation and dewetting, which leads to the formation of a circular contact line around the center of the copper ring. The contact line recedes smoothly toward the copper ring at a constant velocity until reaching a dynamic "stick" state to form the first circular polymer ridge. The average receding velocity is found to be dependent on the dimensions of the copper ring (the copper ring diameter and the cross-sectional diameter of the copper wire) and the thickness of the PMMA films. A model is presented to qualitatively explain the evaporative dewetting phenomenon.

  2. Dynamics of solid thin-film dewetting in the silicon-on-insulator system

    Energy Technology Data Exchange (ETDEWEB)

    Bussmann, E; Cheynis, F; Leroy, F; Mueller, P [Centre Interdisciplinaire de Nanoscience de Marseille (CINaM) CNRS UPR 3118, Aix-Marseille Universite, 13288 Marseille (France); Pierre-Louis, O, E-mail: muller@cinam.univ-mrs.fr [LPMCN, Universite Lyon 1, 43 Bd du 11 novembre, 69622 Villeurbane (France)

    2011-04-15

    Using low-energy electron microscopy movies, we have measured the dewetting dynamics of single-crystal Si(001) thin films on SiO{sub 2} substrates. During annealing (T>700 deg. C), voids open in the Si, exposing the oxide. The voids grow, evolving Si fingers that subsequently break apart into self-organized three-dimensional (3D) Si nanocrystals. A kinetic Monte Carlo model incorporating surface and interfacial free energies reproduces all the salient features of the morphological evolution. The dewetting dynamics is described using an analytic surface-diffusion-based model. We demonstrate quantitatively that Si dewetting from SiO{sub 2} is mediated by surface-diffusion driven by surface free-energy minimization.

  3. Dynamics of solid thin-film dewetting in the silicon-on-insulator system

    Science.gov (United States)

    Bussmann, E.; Cheynis, F.; Leroy, F.; Müller, P.; Pierre-Louis, O.

    2011-04-01

    Using low-energy electron microscopy movies, we have measured the dewetting dynamics of single-crystal Si(001) thin films on SiO2 substrates. During annealing (T>700 °C), voids open in the Si, exposing the oxide. The voids grow, evolving Si fingers that subsequently break apart into self-organized three-dimensional (3D) Si nanocrystals. A kinetic Monte Carlo model incorporating surface and interfacial free energies reproduces all the salient features of the morphological evolution. The dewetting dynamics is described using an analytic surface-diffusion-based model. We demonstrate quantitatively that Si dewetting from SiO2 is mediated by surface-diffusion driven by surface free-energy minimization.

  4. Controllable Fabrication of Au Nanocups by Confined-Space Thermal Dewetting for OCT Imaging.

    Science.gov (United States)

    Gao, Aiqin; Xu, Wenjing; Ponce de León, Yenisey; Bai, Yaocai; Gong, Mingfu; Xie, Kongliang; Park, Boris Hyle; Yin, Yadong

    2017-07-01

    Here, this study reports a novel confined-space thermal dewetting strategy for the fabrication of Au nanocups with tunable diameter, height, and size of cup opening. The nanocup morphology is defined by the cup-shaped void space created by a yolk-shell silica template that spontaneously takes an eccentric configuration during annealing. Thermal dewetting of Au, which is sandwiched between the yolk and shell, leads to the desired nanocup morphology. With strong scattering in near infrared, the Au nanocups exhibit superior efficiency as contrast agents for spectral-domain optical coherence tomography imaging. This confined-space thermal dewetting strategy is scalable and general, and can be potentially extended to the synthesis of novel anisotropic nanostructures of various compositions that are difficult to produce by conventional wet chemical or physical methods, thus opening up opportunities for many new applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Dynamics of solid thin-film dewetting in the silicon-on-insulator system

    International Nuclear Information System (INIS)

    Bussmann, E; Cheynis, F; Leroy, F; Mueller, P; Pierre-Louis, O

    2011-01-01

    Using low-energy electron microscopy movies, we have measured the dewetting dynamics of single-crystal Si(001) thin films on SiO 2 substrates. During annealing (T>700 deg. C), voids open in the Si, exposing the oxide. The voids grow, evolving Si fingers that subsequently break apart into self-organized three-dimensional (3D) Si nanocrystals. A kinetic Monte Carlo model incorporating surface and interfacial free energies reproduces all the salient features of the morphological evolution. The dewetting dynamics is described using an analytic surface-diffusion-based model. We demonstrate quantitatively that Si dewetting from SiO 2 is mediated by surface-diffusion driven by surface free-energy minimization.

  6. Wetting and dewetting of extracellular matrix and glycocalix models

    International Nuclear Information System (INIS)

    Tanaka, Motomu; Rehfeldt, Florian; Schneider, Matthias F; Mathe, Gerald; Albersdoerfer, Antero; Neumaier, Klaus R; Purrucker, Oliver; Sackmann, Erich

    2005-01-01

    In this paper, we study wetting and dewetting of hydrated biopolymer layers mediating cell-cell and cell-tissue contacts, called the extracellular matrix and cell surface glycocalix, by the combination of various physical techniques. Here, the sum of the net effects of the various interfacial forces, which is referred to as the disjoining pressure, is used as a semi-quantitative measure to describe the thermodynamics of hydrated interlayers. The disjoining pressure can be measured by applying external forces to maintain the equilibrium distance between two parallel surfaces (in biology, two neighbouring plasma membranes). Using artificial models of the extracellular matrix and glycocalix, we describe stable cell-cell contacts in terms of the wetting (or spreading) of complex fluids on polymer surfaces. In fact, the adjustment of the wetting interaction via thin hydrating layers enables us to transform three-dimensional cell membranes into quasi-two-dimensional films on macroscopically large surfaces. Fine-tuning of local wetting conditions at the interface further allows for the selective wetting of native cell membranes on microstructured polysaccharide films, which has a large potential for individual detection of biological functions in confined geometries

  7. 1-D Metal Nanobead Arrays within Encapsulated Nanowires via a Red-Ox-Induced Dewetting: Mechanism Study by Atom-Probe Tomography.

    Science.gov (United States)

    Sun, Zhiyuan; Tzaguy, Avra; Hazut, Ori; Lauhon, Lincoln J; Yerushalmi, Roie; Seidman, David N

    2017-12-13

    Metal nanoparticle arrays are excellent candidates for a variety of applications due to the versatility of their morphology and structure at the nanoscale. Bottom-up self-assembly of metal nanoparticles provides an important complementary alternative to the traditional top-down lithography method and makes it possible to assemble structures with higher-order complexity, for example, nanospheres, nanocubes, and core-shell nanostructures. Here we present a mechanism study of the self-assembly process of 1-D noble metal nanoparticles arrays, composed of Au, Ag, and AuAg alloy nanoparticles. These are prepared within an encapsulated germanium nanowire, obtained by the oxidation of a metal-germanium nanowire hybrid structure. The resulting structure is a 1-D array of equidistant metal nanoparticles with the same diameter, the so-called nanobead (NB) array structure. Atom-probe tomography and transmission electron microscopy were utilized to investigate the details of the morphological and chemical evolution during the oxidation of the encapsulated metal-germanium nanowire hybrid-structures. The self-assembly of nanoparticles relies on the formation of a metal-germanium liquid alloy and the migration of the liquid alloy into the nanowire, followed by dewetting of the liquid during shape-confined oxidation where the liquid column breaks-up into nanoparticles due to the Plateau-Rayleigh instability. Our results demonstrate that the encapsulating oxide layer serves as a structural scaffold, retaining the overall shape during the eutectic liquid formation and demonstrates the relationship between the oxide mechanical properties and the final structural characteristics of the 1-D arrays. The mechanistic details revealed here provide a versatile tool-box for the bottom-up fabrication of 1-D arrays nanopatterning that can be modified for multiple applications according to the RedOx properties of the material system components.

  8. Wetting and Dewetting Transitions on Submerged Superhydrophobic Surfaces with Hierarchical Structures.

    Science.gov (United States)

    Wu, Huaping; Yang, Zhe; Cao, Binbin; Zhang, Zheng; Zhu, Kai; Wu, Bingbing; Jiang, Shaofei; Chai, Guozhong

    2017-01-10

    The wetting transition on submersed superhydrophobic surfaces with hierarchical structures and the influence of trapped air on superhydrophobic stability are predicted based on the thermodynamics and mechanical analyses. The dewetting transition on the hierarchically structured surfaces is investigated, and two necessary thermodynamic conditions and a mechanical balance condition for dewetting transition are proposed. The corresponding thermodynamic phase diagram of reversible transition and the critical reversed pressure well explain the experimental results reported previously. Our theory provides a useful guideline for precise controlling of breaking down and recovering of superhydrophobicity by designing superhydrophobic surfaces with hierarchical structures under water.

  9. Insights into the IASB due process: the influence of country characteristics on constituents’ formal participation

    Directory of Open Access Journals (Sweden)

    Karsten Eisenschmidt

    2017-12-01

    Full Text Available The paper explores the impact of country characteristics on constituents’ formal participation in the IASB’s due process. We hypothesize that there is an association between the level of constituents’ partic- ipation and (1 the level of economic development, and (2 the cultural characteristics of the country of origin. We use a number of comment letters (CLs and their length as proxies for constituents’ formal participation in the IASB’s due process. The results indicate that economic development (equity market capitalization is the most important explanatory factor for the different levels of participation. In con- trast, the cultural characteristics measured by Hofstede’s cultural framework can only partially explain that differences. Only individualism is a significant positive influence factor for the level of constituents’ participation. The results of our descriptive analysis for the CLs and the information input provided show that there is still a lack of participation in the IASB’s due process. Despite the huge impact of accounting norms on societies, only a limited number of constituents participate, and some constituent groups, like users or academics, participate less.

  10. Defective motion processing in children with cerebral visual impairment due to periventricular white matter damage.

    Science.gov (United States)

    Weinstein, Joel M; Gilmore, Rick O; Shaikh, Sumera M; Kunselman, Allen R; Trescher, William V; Tashima, Lauren M; Boltz, Marianne E; McAuliffe, Matthew B; Cheung, Albert; Fesi, Jeremy D

    2012-07-01

    We sought to characterize visual motion processing in children with cerebral visual impairment (CVI) due to periventricular white matter damage caused by either hydrocephalus (eight individuals) or periventricular leukomalacia (PVL) associated with prematurity (11 individuals). Using steady-state visually evoked potentials (ssVEP), we measured cortical activity related to motion processing for two distinct types of visual stimuli: 'local' motion patterns thought to activate mainly primary visual cortex (V1), and 'global' or coherent patterns thought to activate higher cortical visual association areas (V3, V5, etc.). We studied three groups of children: (1) 19 children with CVI (mean age 9y 6mo [SD 3y 8mo]; 9 male; 10 female); (2) 40 neurologically and visually normal comparison children (mean age 9y 6mo [SD 3y 1mo]; 18 male; 22 female); and (3) because strabismus and amblyopia are common in children with CVI, a group of 41 children without neurological problems who had visual deficits due to amblyopia and/or strabismus (mean age 7y 8mo [SD 2y 8mo]; 28 male; 13 female). We found that the processing of global as opposed to local motion was preferentially impaired in individuals with CVI, especially for slower target velocities (p=0.028). Motion processing is impaired in children with CVI. ssVEP may provide useful and objective information about the development of higher visual function in children at risk for CVI. © The Authors. Journal compilation © Mac Keith Press 2011.

  11. Ordered to isotropic morphology transition in pattern-directed dewetting of polymer thin films on substrates with different feature heights.

    Science.gov (United States)

    Roy, Sudeshna; Mukherjee, Rabibrata

    2012-10-24

    Controlled dewetting of a thin polymer film on a topographically patterned substrate is an interesting approach for aligning isotropic dewetted structures. In this article, we investigate the influence of substrate feature height (H(S)) on the dewetting pathway and final pattern morphology by studying the dewetting of polystyrene (PS) thin films on grating substrates with identical periodicity (λ(P) = 1.5 μm), but H(S) varying between 10 nm and 120 nm. We identify four distinct categories of final dewetted morphology, with different extent of ordering: (1) array of aligned droplets (H(S) ≈ 120 nm); (2) aligned undulating ribbons (H(S) ≈ 70-100 nm); (3) multilength scale structures with coexisting large droplets uncorrelated to the substrate and smaller droplets/ribbons aligned along the stripes (H(S) ≈ 40-60 nm); and (4) large droplets completely uncorrelated to the substrate (H(S) dewetted morphologies and transition across categories remain generically unaltered. We finally show that the structures obtained by dewetting on different H(S) substrates exhibits different levels of hydrophobicity because of combined spatial variation of chemical and topographic contrast along the surface. Thus, the work reported in this article can find potential application in fabricating surfaces with controlled wettability.

  12. Competitive concurrence of surface wrinkling and dewetting of liquid crystalline polymer films on non-wettable substrates.

    Science.gov (United States)

    Song, Sung E; Choi, Gwan H; Yi, Gi-Ra; Yoo, Pil J

    2017-11-01

    Polymeric thin films coated on non-wettable substrates undergo film-instabilities, which are usually manifested as surface deformation in the form of dewetting or wrinkling. The former takes place in fluidic films, whereas the latter occurs in solid films. Therefore, there have rarely been reports of systems involving simultaneous deformations of dewetting and wrinkling. In this study, we propose polymeric thin films of liquid crystalline (LC) mesogens prepared on a non-wettable Si substrate and apply a treatment of plasma irradiation to form a thin polymerized layer at the surface. The resulting compressive stress generated in the surface region drives the formation of wrinkles, while at the same time, dipolar attraction between LC molecules induces competitive cohesive dewetting. Intriguing surface structures were obtained whereby dewetting-like hole arrays are nested inside the randomly propagated wrinkles. The structural features are readily controlled by the degree of surface cross-linking, hydrophilicity of the substrates, and the LC film thickness. In particular, dewetting of LC mesogens is observed to be restricted to occur at the trough regions of wrinkles, exhibiting the typical behavior of geometrically confined dewetting. Finally, wrinkling-dewetting mixed structures are separated from the substrate in the form of free standing films to demonstrate the potential applicability as membranes.

  13. Induced Current Characteristics Due to Laser Induced Plasma and Its Application to Laser Processing Monitoring

    International Nuclear Information System (INIS)

    Madjid, Syahrun Nur; Idris, Nasrullah; Kurniawan, Koo Hendrik; Kagawa, Kiichiro

    2011-01-01

    In laser processing, suitable conditions for laser and gas play important role in ensuring a high quality of processing. To determine suitable conditions, we employed the electromagnetic phenomena associated with laser plasma generation. An electrode circuit was utilised to detect induced current due to the fast electrons propelled from the material during laser material processing. The characteristics of induced current were examined by changing parameters such as supplied voltage, laser pulse energy, number of laser shots, and type of ambient gas. These characteristics were compared with the optical emission characteristics. It was shown that the induced current technique proposed in this study is much more sensitive than the optical method in monitoring laser processing, that is to determine the precise focusing condition, and to accurately determine the moment of completion of laser beam penetration. In this study it was also shown that the induced current technique induced by CW CO 2 laser can be applied in industrial material processing for monitoring the penetration completion in a stainless steel plate drilling process.

  14. Structure Formation of Ultrathin PEO Films at Solid Interfaces—Complex Pattern Formation by Dewetting and Crystallization

    Science.gov (United States)

    Braun, Hans-Georg; Meyer, Evelyn

    2013-01-01

    The direct contact of ultrathin polymer films with a solid substrate may result in thin film rupture caused by dewetting. With crystallisable polymers such as polyethyleneoxide (PEO), molecular self-assembly into partial ordered lamella structures is studied as an additional source of pattern formation. Morphological features in ultrathin PEO films (thickness dewetting patterns and diffusion limited growth pattern of ordered lamella growing within the dewetting areas. Besides structure formation of hydrophilic PEO molecules, n-alkylterminated (hydrophobic) PEO oligomers are investigated with respect to self-organization in ultrathin films. Morphological features characteristic for pure PEO are not changed by the presence of the n-alkylgroups. PMID:23385233

  15. Influence of germanium on thermal dewetting and agglomeration of the silicon template layer in thin silicon-on-insulator

    International Nuclear Information System (INIS)

    Zhang, P P; Yang, B; Rugheimer, P P; Roberts, M M; Savage, D E; Lagally, M G; Liu Feng

    2009-01-01

    We investigate the influence of heteroepitaxially grown Ge on the thermal dewetting and agglomeration of the Si(0 0 1) template layer in ultrathin silicon-on-insulator (SOI). We show that increasing Ge coverage gradually destroys the long-range ordering of 3D nanocrystals along the (1 3 0) directions and the 3D nanocrystal shape anisotropy that are observed in the dewetting and agglomeration of pure SOI(0 0 1). The results are qualitatively explained by Ge-induced bond weakening and decreased surface energy anisotropy. Ge lowers the dewetting and agglomeration temperature to as low as 700 0 C.

  16. Unusual dewetting of thin polymer films in liquid media containing a poor solvent and a nonsolvent.

    Science.gov (United States)

    Xu, Lin; Sharma, Ashutosh; Joo, Sang Woo; Liu, Hui; Shi, Tongfei

    2014-12-16

    We investigate the control of pattern size and kinetics in spontaneous dewetting of thin polymer films (polystyrene) that are stable to thermal annealing by annealing in a poor solvent (acetone)/nonsolvent (ethanol or n-hexane) liquid mixture. Dewetting occurs by the formation and growth of circular holes that coalesce to form droplets. The influence of the nature and the volume fraction of the nonsolvents on the contact angle of polymer droplets, number density of holes, and the kinetics of holes formation and growth is studied. Addition of ethanol greatly increases the hole density and slows down the kinetics substantially, while affecting only a small change in wettability. n-Hexane addition shows an interesting nonmonotonic response in decreasing the hole density and contact angle in the volume fraction range of 0-0.3 but an opposite effect beyond that. Although the two nonsolvents chosen cannot by themselves induce dewetting, their relative affinity for the solid substrate vis-à-vis acetone can strongly influence the observed dewetting scenarios that are not understood by the existing theoretical considerations. n-Hexane, for example, has great affinity for silicon substrate. In addition to the changes in wettability, viscosity, and film interfacial tension engendered by the nonsolvents, the possibility of the formation of adsorbed liquid layers at the substrate-polymer interface, which can modify the interfacial friction and slippage, needs to be considered.

  17. Directed dewetting of amorphous silicon film by a donut-shaped laser pulse

    International Nuclear Information System (INIS)

    Yoo, Jae-Hyuck; Zheng, Cheng; Grigoropoulos, Costas P; In, Jung Bin; Sakellari, Ioanna; Raman, Rajesh N; Matthews, Manyalibo J; Elhadj, Selim

    2015-01-01

    Irradiation of a thin film with a beam-shaped laser is proposed to achieve site-selectively controlled dewetting of the film into nanoscale structures. As a proof of concept, the laser-directed dewetting of an amorphous silicon thin film on a glass substrate is demonstrated using a donut-shaped laser beam. Upon irradiation of a single laser pulse, the silicon film melts and dewets on the substrate surface. The irradiation with the donut beam induces an unconventional lateral temperature profile in the film, leading to thermocapillary-induced transport of the molten silicon to the center of the beam spot. Upon solidification, the ultrathin amorphous silicon film is transformed to a crystalline silicon nanodome of increased height. This morphological change enables further dimensional reduction of the nanodome as well as removal of the surrounding film material by isotropic silicon etching. These results suggest that laser-based dewetting of thin films can be an effective way for scalable manufacturing of patterned nanostructures. (paper)

  18. Directed dewetting of amorphous silicon film by a donut-shaped laser pulse.

    Science.gov (United States)

    Yoo, Jae-Hyuck; In, Jung Bin; Zheng, Cheng; Sakellari, Ioanna; Raman, Rajesh N; Matthews, Manyalibo J; Elhadj, Selim; Grigoropoulos, Costas P

    2015-04-24

    Irradiation of a thin film with a beam-shaped laser is proposed to achieve site-selectively controlled dewetting of the film into nanoscale structures. As a proof of concept, the laser-directed dewetting of an amorphous silicon thin film on a glass substrate is demonstrated using a donut-shaped laser beam. Upon irradiation of a single laser pulse, the silicon film melts and dewets on the substrate surface. The irradiation with the donut beam induces an unconventional lateral temperature profile in the film, leading to thermocapillary-induced transport of the molten silicon to the center of the beam spot. Upon solidification, the ultrathin amorphous silicon film is transformed to a crystalline silicon nanodome of increased height. This morphological change enables further dimensional reduction of the nanodome as well as removal of the surrounding film material by isotropic silicon etching. These results suggest that laser-based dewetting of thin films can be an effective way for scalable manufacturing of patterned nanostructures.

  19. 3D Dewetting for Crystal Patterning: Toward Regular Single-Crystalline Belt Arrays and Their Functionality.

    Science.gov (United States)

    Wu, Yuchen; Feng, Jiangang; Su, Bin; Jiang, Lei

    2016-03-16

    Arrays of unidirectional dewetting behaviors can be generated by using 3D-wettability-difference micropillars, yielding highly ordered organic single-crystalline belt arrays. These patterned organic belts show an improved mobility record and can be used as flexible pressure sensors with high sensitivity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Coexistence of Two Singularities in Dewetting Flows: Regularizing the Corner Tip

    NARCIS (Netherlands)

    Peters, I.R.; Snoeijer, Jacobus Hendrikus; Daerr, Adrian; Limat, Laurent

    2009-01-01

    Entrainment in wetting and dewetting flows often occurs through the formation of a corner with a very sharp tip. This corner singularity comes on top of the divergence of viscous stress near the contact line, which is only regularized at molecular scales. We investigate the fine structure of corners

  1. Dewetting of thin film blends containing block copolymer: effects of nonadsorbing block length and substrate hydrophobicity

    Czech Academy of Sciences Publication Activity Database

    Costa, A. C.; Composto, R. J.; Vlček, Petr

    2003-01-01

    Roč. 36, č. 9 (2003), s. 3254-3260 ISSN 0024-9297 R&D Projects: GA AV ČR KSK4050111 Keywords : polymer films * adsorption * dewetting Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.621, year: 2003

  2. Tube failures due to cooling process problem and foreign materials in power plants

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, J. [Kapar Energy Ventures Sdn Bhd, Jalan Tok Muda, Kapar 42200 (Malaysia); Purbolaksono, J., E-mail: judha@uniten.edu.m [Department of Mechanical Engineering, Universiti Tenaga Nasional, Km 7 Jalan Kajang-Puchong, Kajang 43009, Selangor (Malaysia); Beng, L.C. [Kapar Energy Ventures Sdn Bhd, Jalan Tok Muda, Kapar 42200 (Malaysia)

    2010-07-15

    Cooling process which uses water for heat transfer is an essential factor in coal-fired and nuclear plants. Loss of cooling upset can force the plants to shut down. In particular, this paper reports visual inspections and metallurgical examinations on the failed SA210-A1 right-hand side (RHS) water wall tube of a coal-fired plant. The water wall tube showed the abnormal outer surface colour and has failed with wide-open ductile rupture and thin edges indicating typical signs of short-term overheating. Metallurgical examinations confirmed the failed tube experiencing higher temperature operation. Water flow starvation due to restriction inside the upstream tube is identified as the main root cause of failure. The findings are important to take failure mitigation actions in the future operation. Discussion on the typical problems related to the cooling process in nuclear power plants is also presented.

  3. Tube failures due to cooling process problem and foreign materials in power plants

    International Nuclear Information System (INIS)

    Ahmad, J.; Purbolaksono, J.; Beng, L.C.

    2010-01-01

    Cooling process which uses water for heat transfer is an essential factor in coal-fired and nuclear plants. Loss of cooling upset can force the plants to shut down. In particular, this paper reports visual inspections and metallurgical examinations on the failed SA210-A1 right-hand side (RHS) water wall tube of a coal-fired plant. The water wall tube showed the abnormal outer surface colour and has failed with wide-open ductile rupture and thin edges indicating typical signs of short-term overheating. Metallurgical examinations confirmed the failed tube experiencing higher temperature operation. Water flow starvation due to restriction inside the upstream tube is identified as the main root cause of failure. The findings are important to take failure mitigation actions in the future operation. Discussion on the typical problems related to the cooling process in nuclear power plants is also presented.

  4. Average thermal stress in the Al+SiC composite due to its manufacturing process

    International Nuclear Information System (INIS)

    Miranda, Carlos A.J.; Libardi, Rosani M.P.; Marcelino, Sergio; Boari, Zoroastro M.

    2013-01-01

    The numerical analyses framework to obtain the average thermal stress in the Al+SiC Composite due to its manufacturing process is presented along with the obtained results. The mixing of Aluminum and SiC powders is done at elevated temperature and the usage is at room temperature. A thermal stress state arises in the composite due to the different thermal expansion coefficients of the materials. Due to the particles size and randomness in the SiC distribution, some sets of models were analyzed and a statistical procedure used to evaluate the average stress state in the composite. In each model the particles position, form and size are randomly generated considering a volumetric ratio (VR) between 20% and 25%, close to an actual composite. The obtained stress field is represented by a certain number of iso stress curves, each one weighted by the area it represents. Systematically it was investigated the influence of: (a) the material behavior: linear x non-linear; (b) the carbide particles form: circular x quadrilateral; (c) the number of iso stress curves considered in each analysis; and (e) the model size (the number of particles). Each of above analyzed condition produced conclusions to guide the next step. Considering a confidence level of 95%, the average thermal stress value in the studied composite (20% ≤ VR ≤ 25%) is 175 MPa with a standard deviation of 10 MPa. Depending on its usage, this value should be taken into account when evaluating the material strength. (author)

  5. Due Diligence Processes for Public Acquisition of Mining-Impacted Landscapes

    Science.gov (United States)

    Martin, E.; Monohan, C.; Keeble-Toll, A. K.

    2016-12-01

    The acquisition of public land is critical for achieving conservation and habitat goals in rural regions projected to experience continuously high rates of population growth. To ensure that public funds are utilized responsibly in the purchase of conservation easements appropriate due diligence processes must be established that limit landowner liability post-acquisition. Traditional methods of characterizing contamination in regions where legacy mining activities were prevalent may not utilize current scientific knowledge and understanding of contaminant fate, transport and bioavailability, and therefore are likely to have type two error. Agency prescribed assessment methods utilized under CERLA in many cases fail to detect contamination that presents liability issues by failing to require water quality sampling that would reveal offsite transport potential of contaminants posing human health risks, including mercury. Historical analysis can be used to inform judgmental sampling to identify hotspots and contaminants of concern. Land acquisition projects at two historic mine sites in Nevada County, California, the Champion Mine Complex and the Black Swan Preserve have established the necessity of re-thinking due diligence processes for mining-impacted landscapes. These pilot projects demonstrate that pre-acquisition assessment in the Gold Country must include judgmental sampling and evaluation of contaminant transport. Best practices using the current scientific knowledge must be codified by agencies, consultants, and NGOs in order to ensure responsible use of public funds and to safeguard public health.

  6. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    International Nuclear Information System (INIS)

    Subramanian, V.; Chandramohan, P.; Srinivasan, M.P.; Rangarajan, S.; Velmurugan, S.; Narasimhan, S.V.; Khandelwal, R.C.

    2010-01-01

    Some of the Indian PHWRs which used stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit encountered high radiation field in moderator system due to 60 Co. Release of particulate stellite was responsible for the hotspots besides the general uniform contamination of internal surfaces with 60 Co. Extensive laboratory studies have shown that it is possible to dissolve these stellite particles by adopting a three step redox process with permanganic acid as the oxidizing agent. These investigations with inactive stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The concentration of the permanganate was also found to be an important factor in deciding the efficiency of the dissolution of stellite. The efficiency of dissolution as a function of permanganic acid concentration showed a maximum. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had 60 Co activity due to stellite particles with the radiation field ranging from 3 R/h to 20 R/h. They were subjected to decontamination with permanganic acid as oxidizing agent, followed by citric acid and a solution containing EDTA, ascorbic acid and citric acid in 4:3:3 ratio by weight (EAC) as reducing formulations. A test rig was fabricated for this purpose. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7 was achieved. The same process but one cycle was repeated on eight more adjustor rod drive mechanisms. 60 Co activity in the range of 13 - 93 mCi was removed from these adjustor rods. Loose contamination of the order of 30000 - 40000 dpm/cm 2 observed before decontamination

  7. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, V.; Chandramohan, P.; Srinivasan, M.P.; Rangarajan, S.; Velmurugan, S.; Narasimhan, S.V., E-mail: svn@igcar.gov.in [BARC Facilities, Water and Steam Chemistry Div., Kalpakkam, Tamilnadu (India); Khandelwal, R.C. [Kakrapara Atomic Power Station, KAPS, Surat, Gujarat (India)

    2010-07-01

    Some of the Indian PHWRs which used stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit encountered high radiation field in moderator system due to {sup 60}Co. Release of particulate stellite was responsible for the hotspots besides the general uniform contamination of internal surfaces with {sup 60}Co. Extensive laboratory studies have shown that it is possible to dissolve these stellite particles by adopting a three step redox process with permanganic acid as the oxidizing agent. These investigations with inactive stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The concentration of the permanganate was also found to be an important factor in deciding the efficiency of the dissolution of stellite. The efficiency of dissolution as a function of permanganic acid concentration showed a maximum. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had {sup 60}Co activity due to stellite particles with the radiation field ranging from 3 R/h to 20 R/h. They were subjected to decontamination with permanganic acid as oxidizing agent, followed by citric acid and a solution containing EDTA, ascorbic acid and citric acid in 4:3:3 ratio by weight (EAC) as reducing formulations. A test rig was fabricated for this purpose. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7 was achieved. The same process but one cycle was repeated on eight more adjustor rod drive mechanisms. {sup 60}Co activity in the range of 13 - 93 mCi was removed from these adjustor rods. Loose contamination of the order of 30000 - 40000 dpm/cm{sup 2} observed

  8. 20 CFR 670.545 - How does Job Corps ensure that students receive due process in disciplinary actions?

    Science.gov (United States)

    2010-04-01

    ... receive due process in disciplinary actions? 670.545 Section 670.545 Employees' Benefits EMPLOYMENT AND... process in disciplinary actions? The center operator must ensure that all students receive due process in disciplinary proceedings according to procedures developed by the Secretary. These procedures must include, at...

  9. Mediation and Due Process Procedures in Special Education: An Analysis of State Policies. Final Report. Project FORUM.

    Science.gov (United States)

    Ahearn, Eileen M.

    This survey of 50 states and 3 of 10 non-state U.S. jurisdictions concerning state due process procedures focuses mainly on the use of mediation as a form of dispute resolution that offers an alternative to due process hearings in special education. A background section discusses the definition of mediation and the mediation process. Survey…

  10. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    International Nuclear Information System (INIS)

    Subramanian, Veena; Chandramohan, Palogi; Chandran, Sinu; Srinivasan, Madapusi P.; Rangarajan, Srinivasan; Velmurugan, Sankaralingam; Narasimhan, Sevilmedu V.

    2011-01-01

    Some of the Indian pressurized heavy water reactors (PHWRs) which use Stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit have encountered high radiation fields in the moderator system due to 60 Co. Release of particulate Stellite is responsible for the hotspots in addition to the general uniform contamination of internal surfaces with 60 Co. Extensive laboratory studies have shown that it is possible to dissolve these Stellite particles by adopting a three-step redox process with permanganic acid as the oxidizing agent. These investigations with inactive Stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The susceptibility of Stellite to corrode or dissolve was found to depend on the concentration of the permanganate, pH and temperature of the process and microstructure of the Stellite alloy. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had 60 Co activity due to Stellite particles with the radiation field ranging from 3 R . h -1 to 20 R . h -1 . They were subjected to decontamination with permanganic acid as the oxidizing agent, followed by citric acid and a solution containing ethylenediaminetetraacetic acid, ascorbic acid and citric acid in a 4:3:3 ratio by weight as the reducing formulation. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7, was achieved. The same process but with one cycle was repeated on eight more adjustor rod drive mechanisms. 60 Co activity in the range of 13-93 mCi was removed from these adjustor rods. Loose contamination of the order of 30 000-40 000 decays per min and cm 2 observed

  11. Evaluation of a process for the decontamination of radioactive hotspots due to activated stellite particles

    Energy Technology Data Exchange (ETDEWEB)

    Subramanian, Veena; Chandramohan, Palogi; Chandran, Sinu; Srinivasan, Madapusi P.; Rangarajan, Srinivasan; Velmurugan, Sankaralingam; Narasimhan, Sevilmedu V. [BARC Facilities, Kalpakkam, Tamil Nadu (India). Water and Steam Chemistry Div.

    2011-06-15

    Some of the Indian pressurized heavy water reactors (PHWRs) which use Stellite balls in the ball and screw mechanism of the adjustor rod drive mechanism in the moderator circuit have encountered high radiation fields in the moderator system due to {sup 60}Co. Release of particulate Stellite is responsible for the hotspots in addition to the general uniform contamination of internal surfaces with {sup 60}Co. Extensive laboratory studies have shown that it is possible to dissolve these Stellite particles by adopting a three-step redox process with permanganic acid as the oxidizing agent. These investigations with inactive Stellite in powder form helped to optimize the process conditions. Permanganic acid was found to have the highest dissolution efficiency as compared to alkaline and nitric acid permanganate. The susceptibility of Stellite to corrode or dissolve was found to depend on the concentration of the permanganate, pH and temperature of the process and microstructure of the Stellite alloy. This process was evaluated for its effectiveness on components from nuclear power plants. Component decontamination was carried out on adjustor rod drive assemblies which had {sup 60}Co activity due to Stellite particles with the radiation field ranging from 3 R . h{sup -1} to 20 R . h{sup -1}. They were subjected to decontamination with permanganic acid as the oxidizing agent, followed by citric acid and a solution containing ethylenediaminetetraacetic acid, ascorbic acid and citric acid in a 4:3:3 ratio by weight as the reducing formulation. In the first trial, one adjustor rod drive mechanism was subjected to decontamination. After two cycles of treatment, an average decontamination factor (DF) of 6.8, with a maximum DF of 11.7, was achieved. The same process but with one cycle was repeated on eight more adjustor rod drive mechanisms. {sup 60}Co activity in the range of 13-93 mCi was removed from these adjustor rods. Loose contamination of the order of 30 000-40 000

  12. Temperature resolution enhancing of commercially available THz passive cameras due to computer processing of images

    Science.gov (United States)

    Trofimov, Vyacheslav A.; Trofimov, Vladislav V.; Kuchik, Igor E.

    2014-06-01

    As it is well-known, application of the passive THz camera for the security problems is very promising way. It allows seeing concealed object without contact with a person and this camera is non-dangerous for a person. Efficiency of using the passive THz camera depends on its temperature resolution. This characteristic specifies possibilities of the detection of concealed object: minimal size of the object, maximal distance of the detection, image detail. One of probable ways for a quality image enhancing consists in computer processing of image. Using computer processing of the THz image of objects concealed on the human body, one may improve it many times. Consequently, the instrumental resolution of such device may be increased without any additional engineering efforts. We demonstrate new possibilities for seeing the clothes details, which raw images, produced by the THz cameras, do not allow to see. We achieve good quality of the image due to applying various spatial filters with the aim to demonstrate independence of processed images on math operations. This result demonstrates a feasibility of objects seeing. We consider images produced by THz passive cameras manufactured by Microsemi Corp., and ThruVision Corp., and Capital Normal University (Beijing, China).

  13. Adaptive memory: the survival-processing memory advantage is not due to negativity or mortality salience.

    Science.gov (United States)

    Bell, Raoul; Röer, Jan P; Buchner, Axel

    2013-05-01

    Recent research has highlighted the adaptive function of memory by showing that imagining being stranded in the grasslands without any survival material and rating words according to their survival value in this situation leads to exceptionally good memory for these words. Studies examining the role of emotions in causing the survival-processing memory advantage have been inconclusive, but some studies have suggested that the effect might be due to negativity or mortality salience. In Experiments 1 and 2, we compared the survival scenario to a control scenario that implied imagining a hopeless situation (floating in outer space with dwindling oxygen supplies) in which only suicide can avoid the agony of choking to death. Although this scenario was perceived as being more negative than the survival scenario, the survival-processing memory advantage persisted. In Experiment 3, thinking about the relevance of words for survival led to better memory for these words than did thinking about the relevance of words for death. This survival advantage was found for concrete, but not for abstract, words. The latter finding is consistent with the assumption that the survival instructions encourage participants to think about many different potential uses of items to aid survival, which may be a particularly efficient form of elaborate encoding. Together, the results suggest that thinking about death is much less effective in promoting recall than is thinking about survival. Therefore, the survival-processing memory advantage cannot be satisfactorily explained by negativity or mortality salience.

  14. Accommodaton of constitutional due process rights within the new patients' rights legislation in Slovenia.

    Science.gov (United States)

    Ivanc, Blaz

    2011-09-01

    The Constitutional Court of the Republic of Slovenia issued several decisions concerning the protection of patients' rights (e.g. decisions on involuntary commitment, on access to health care, on rights related to obligatory and voluntary health insurance). Consequently, the Parliament renewed Health Legislation by the enactment of the Patients' Rights Act (February 2008) and of the Mental Health Act (July 2008). Both bills enshrine a charter of patients' rights that may be considered as concretization of several human rights that are protected by the Constitution. The discussion is focused on the due process rights (e.g. equal protection of rights, right to judicial protection, right to legal remedies, legal guarantees in proceedings related to deprivation of personal liberty) that were in particular addressed by the Court. The results demonstrate that their effective implementation was one of the most important demands that the Legislature had to accommodate when enacting new bills.

  15. South African, Rural ICT Implementation: a critical retrospective application of Latour's due process model

    Directory of Open Access Journals (Sweden)

    Jo Rhodes

    2004-05-01

    Full Text Available The potential developmental role of ICTs can pressurise governments to engage in ‘catch up’ and ‘leapfrog’. Consequently, analysis of the accompanying socio-political dimensions and risks can be, disastrously, neglected. This paper examines a specific technology implementation – a South African government sponsored telecentre using Latour’s Due Process model, an analytical tool grounded in Actor-Network Theory, where technology implementation is viewed as a symmetrical treatment of technology and society within a single collective. It is used here, retrospectively, to make sense of why the telecentre both failed to institutionalise within a successful actor-network, and, contributed to the destabilization and partial destruction of a successfully established women’s development organisation.

  16. Anomalous diffusion due to hindering by mobile obstacles undergoing Brownian motion or Orstein-Ulhenbeck processes.

    Science.gov (United States)

    Berry, Hugues; Chaté, Hugues

    2014-02-01

    In vivo measurements of the passive movements of biomolecules or vesicles in cells consistently report "anomalous diffusion," where mean-squared displacements scale as a power law of time with exponent αmovement hindrance by obstacles is often invoked. However, our understanding of how hindered diffusion leads to subdiffusion is based on diffusion amidst randomly located immobile obstacles. Here, we have used Monte Carlo simulations to investigate transient subdiffusion due to mobile obstacles with various modes of mobility. Our simulations confirm that the anomalous regimes rapidly disappear when the obstacles move by Brownian motion. By contrast, mobile obstacles with more confined displacements, e.g., Orstein-Ulhenbeck motion, are shown to preserve subdiffusive regimes. The mean-squared displacement of tracked protein displays convincing power laws with anomalous exponent α that varies with the density of Orstein-Ulhenbeck (OU) obstacles or the relaxation time scale of the OU process. In particular, some of the values we observed are significantly below the universal value predicted for immobile obstacles in two dimensions. Therefore, our results show that subdiffusion due to mobile obstacles with OU type of motion may account for the large variation range exhibited by experimental measurements in living cells and may explain that some experimental estimates are below the universal value predicted for immobile obstacles.

  17. Research Amplitudo Vibration On Holder Due To The Process Of Lathe Nozzle Rocket RX 450

    Science.gov (United States)

    Ediwan; Budi Djatmiko, Agus; Dody Arisandi, EfFendy; Purnomo, Heri; Ibadi, Mahfud

    2018-04-01

    The main function of the rocket nozzle is to convert the enthalpy efficiency from combustion gas to kinetic energy and also to make high velocity out of the gas. The rocket nozzle usually consists of a converging and diverging part. With a smaller area on the neck and enlarged at the exit area. The velocity flow through the nozzle enlarges into the speed of sound through the neck and then becomes super sonic in the divergent part. Nozzle making or machining using conventional lathes, first performed is drilling on a massive metal that is bonded to the veneer, then after a sufficient gap is done deep-boring. At the time of the process of lathe in the nozzle RX 450 there is an obstacle that is vibrating tool holder chisel or holder so it is worried about not precision of the process of lathe. This should not happen because it can cause failure in the latter for it needs to be studied and studied further so that the lathe process goes accordingly. The holder material of ST 60 with a modulus of elasticity 200 GPa and a nozzle material of AISI 4340 alloy steel with σyield = 470 MPa, Shear Modulus G = 80 GPa. The purpose of this research is to observe the amplitude of vibration on the holder due to RX- 450 nozzle lathe processing for the purpose of amplitude that occurs in accordance with the desired so that the nozzle structure is no damage process. The result of the research was obtained holder with length (L) 80cm, profile width (B) 5 cm, height of profile (H) 10 cm, turning machine ω = 8.98 rad / sec and natural holder frequency ωn = 89.8 rad / second, Amplitude of vibration of δ = 1.21 mm, while the amplitude of the design X = 1.22 mm From the results of this study it can be said that the holder of a chisel or holder can be used as a tool at the time of RX nozzle retrieval process and is quite safe because it works under the condition ω/ω n Rocket Payload "AKPV Engineering University of Wyoming 2009 )

  18. Hierarchical Micro/Nano Structures by Combined Self-Organized Dewetting and Photopatterning of Photoresist Thin Films.

    Science.gov (United States)

    Sachan, Priyanka; Kulkarni, Manish; Sharma, Ashutosh

    2015-11-17

    Photoresists are the materials of choice for micro/nanopatterning and device fabrication but are rarely used as a self-assembly material. We report for the first time a novel interplay of self-assembly and photolithography for fabrication of hierarchical and ordered micro/nano structures. We create self-organized structures by the intensified dewetting of unstable thin (∼10 nm to 1 μm) photoresist films by annealing them in an optimal solvent and nonsolvent liquid mixture that allows spontaneous dewetting to form micro/nano smooth dome-like structures. The density, size (∼100 nm to millimeters), and curvature/contact angle of the dome/droplet structures are controlled by the film thickness, composition of the dewetting liquid, and time of annealing. Ordered dewetted structures are obtained simply by creating spatial variation of viscosity by ultraviolet exposure or by photopatterning before dewetting. Further, the structures thus fabricated are readily photopatterned again on the finer length scales after dewetting. We illustrate the approach by fabricating several three-dimensional structures of varying complexity with secondary and tertiary features.

  19. Solvent annealing induced phase separation and dewetting in PMMA∕SAN blend film: film thickness and solvent dependence.

    Science.gov (United States)

    You, Jichun; Zhang, Shuangshuang; Huang, Gang; Shi, Tongfei; Li, Yongjin

    2013-06-28

    The competition between "dewetting" and "phase separation" behaviors in polymer blend films attracts significant attention in the last decade. The simultaneous phase separation and dewetting in PMMA∕SAN [poly(methyl methacrylate) and poly(styrene-ran-acrylonitrile)] blend ultrathin films upon solvent annealing have been observed for the first time in our previous work. In this work, film thickness and annealing solvent dependence of phase behaviors in this system has been investigated using atomic force microscopy and grazing incidence small-angle X-ray scattering (GISAXS). On one hand, both vertical phase separation and dewetting take place upon selective solvent vapor annealing, leading to the formation of droplet∕mimic-film structures with various sizes (depending on original film thickness). On the other hand, the whole blend film dewets the substrate and produces dispersed droplets on the silicon oxide upon common solvent annealing. GISAXS results demonstrate the phase separation in the big dewetted droplets resulted from the thicker film (39.8 nm). In contrast, no period structure is detected in small droplets from the thinner film (5.1 nm and 9.7 nm). This investigation indicates that dewetting and phase separation in PMMA∕SAN blend film upon solvent annealing depend crucially on the film thickness and the atmosphere during annealing.

  20. Phase transformations in Au(Fe) nano- and microparticles obtained by solid state dewetting of thin Au–Fe bilayer films

    International Nuclear Information System (INIS)

    Amram, D.; Klinger, L.; Rabkin, E.

    2013-01-01

    Sub-micrometer-sized particles of Au–Fe alloys were obtained by solid-state dewetting of single-crystalline Au–Fe bilayer films, deposited on c-plane sapphire (α-Al 2 O 3 ) substrates. Depending on the annealing parameters, precipitation of an Fe-rich phase occurred on the side facets of the particles in an interface-limited reaction. Based on the literature values of surface and interface energies in the system, the precipitates were expected to grow inside the Au(Fe) particles, resulting in an (Fe) core–(Au) shell morphology. However, more complex, time-dependent precipitate morphologies were observed, with faceted Fe-rich precipitates attached to the parent faceted Au-rich particles of the same height being dominant at the last stages of the transformation. Our high-resolution transmission electron microscopy observations revealed a nanometric segregation layer of Au on the surface of Fe-rich particles and at their interface with sapphire. This segregation layer modified the surface and interface energies of the Fe-rich particles. A thermodynamic transformation model based on the concept of weighted mean curvature was developed, describing the kinetics of precipitations and morphology evolution of the particles during the dewetting process. Employing the values of surface and interface energies modified by segregation resulted in a good qualitative agreement between theory and experiment

  1. Fabrication of highly oriented D0{sub 3}-Fe{sub 3}Si nanocrystals by solid-state dewetting of Si ultrathin layer

    Energy Technology Data Exchange (ETDEWEB)

    Naito, Muneyuki, E-mail: naito22@center.konan-u.ac.jp [Department of Chemistry, Konan University, Okamoto, Higashinada, Kobe, Hyogo 658-8501 (Japan); Nakagawa, Tatsuhiko; Machida, Nobuya; Shigematsu, Toshihiko [Department of Chemistry, Konan University, Okamoto, Higashinada, Kobe, Hyogo 658-8501 (Japan); Nakao, Motoi [Graduate School of Engineering, Kyushu Institute of Technology, Sensui, Tobata, Kitakyushu, Fukuoka 804-8550 (Japan); Sudoh, Koichi [The Institute of Scientific and Industrial Research, Osaka University, Mihogaoka, Ibaraki, Osaka 567-0047 (Japan)

    2013-07-31

    In this paper, highly oriented nanocrystals of Fe{sub 3}Si with a D0{sub 3} structure are fabricated on SiO{sub 2} using ultrathin Si on insulator substrate. First, (001) oriented Si nanocrystals are formed on the SiO{sub 2} layer by solid state dewetting of the top Si layer. Then, Fe addition to the Si nanocrystals is performed by reactive deposition epitaxy and post-deposition annealing at 500 °C. The structures of the Fe–Si nanocrystals are analyzed by cross-sectional transmission electron microscopy and nanobeam electron diffraction. We observe that Fe{sub 3}Si nanocrystals with D0{sub 3}, B2, and A2 structures coexist on the 1-h post-annealed samples. Prolonged annealing at 500 °C is effective in obtaining Fe{sub 3}Si nanocrystals with a D0{sub 3} single phase, thereby promoting structural ordering in the nanocrystals. We discuss the formation process of the highly oriented D0{sub 3}-Fe{sub 3}Si nanocrystals on the basis of the atomistic structural information. - Highlights: • Highly oriented Fe–Si nanocrystals (NCs) are fabricated by reactive deposition. • Si NCs formed by solid state dewetting of Si thin layers are used as seed crystals. • The structures of Fe–Si NCs are analyzed by nanobeam electron diffraction. • Most of Fe–Si NCs possess the D0{sub 3} structure after post-deposition annealing.

  2. Evidences of landslide earthquake triggering due to self-excitation process

    Science.gov (United States)

    Bozzano, F.; Lenti, L.; Martino, Salvatore; Paciello, A.; Scarascia Mugnozza, G.

    2011-06-01

    The basin-like setting of stiff bedrock combined with pre-existing landslide masses can contribute to seismic amplifications in a wide frequency range (0-10 Hz) and induce a self-excitation process responsible for earthquake-triggered landsliding. Here, the self-excitation process is proposed to justify the far-field seismic trigger of the Cerda landslide (Sicily, Italy) which was reactivated by the 6th September 2002 Palermo earthquake ( M s = 5.4), about 50 km far from the epicentre. The landslide caused damage to farm houses, roads and aqueducts, close to the village of Cerda, and involved about 40 × 106 m3 of clay shales; the first ground cracks due to the landslide movement formed about 30 min after the main shock. A stress-strain dynamic numerical modelling, performed by FDM code FLAC 5.0, supports the notion that the combination of local geological setting and earthquake frequency content played a fundamental role in the landslide reactivation. Since accelerometric records of the triggering event are not available, dynamic equivalent inputs have been used for the numerical modelling. These inputs can be regarded as representative for the local ground shaking, having a PGA value up to 0.2 m/s2, which is the maximum expected in 475 years, according to the Italian seismic hazard maps. A 2D numerical modelling of the seismic wave propagation in the Cerda landslide area was also performed; it pointed out amplification effects due to both the structural setting of the stiff bedrock (at about 1 Hz) and the pre-existing landslide mass (in the range 3-6 Hz). The frequency peaks of the resulting amplification functions ( A( f)) fit well the H/ V spectral ratios from ambient noise and the H/ H spectral ratios to a reference station from earthquake records, obtained by in situ velocimetric measurements. Moreover, the Fourier spectra of earthquake accelerometric records, whose source and magnitude are consistent with the triggering event, show a main peak at about 1 Hz

  3. Impact of pH on hydrogen oxidizing redox processes in aquifers due to gas intrusions

    Science.gov (United States)

    Metzgen, Adrian; Berta, Marton; Dethlefsen, Frank; Ebert, Markus; Dahmke, Andreas

    2017-04-01

    Hydrogen production from excess energy and its storage can help increasing the efficiency of solar and wind in the energy mix. Therefore, hydrogen needs large-scale intermediate storage independent of the intended later use as hydrogen gas or as reactant to produce methane in the Sabatier process. A possible storage solution is using the geological subsurface such as caverns built in salt deposits or aquifers that are not used for drinking water production. However, underground storage of hydrogen gas potentially leads to accidental gas leakages into near-surface potable aquifers triggering subsequent geochemical processes. These leakages pose potential risks that are currently not sufficiently understood. To close this gap in knowledge, a high-pressure laboratory column system was used to simulate a hydrogen gas intrusion into a shallow aquifer. Water and sediment were gained from a sandy Pleistocene aquifer near Neumünster, Germany. In the first stage of the experiment, 100% hydrogen gas was used to simulate dissolved hydrogen concentrations between 800 and 4000 µM by varying pH2 between 2 and 15 bars. pH values rose to between 7.9 and 10.4, partly due to stripping CO2 from the groundwater used during H2 gas addition. In a second stage, the pH was regulated in a range of 6.7 to 7.9 by using a gas mixture of 99% H2 and 1% CO2 at 5 bars of total gas pressure. Observed processes included hydrogen oxidation, sulfate reduction, acetogenesis, formate production, and methanogenesis, which were independent of the hydrogen concentration. Hydrogen oxidation and sulfate reduction showed zeroth order reaction rates and rate constants (106 to 412 µM/h and 12 to 33 µM/h, respectively) in the pH range between 8 and 10. At pH levels between 7 and 8, both reactions started out faster near the column's inflow but then seemed limited towards the columns outflow, suggesting the dependence of sulfate reduction on the pH-value. Acetogenesis dominated the pH range between 8 and 10

  4. SILTATION AND EROSION PROCESSES ON A TRIBUTARY OF LAKE ITAIPU DUE A DAM RESERVOIR

    Directory of Open Access Journals (Sweden)

    Cristiano Poleto

    2012-12-01

    creating an imbalance between the small amount of sediment transported after the hydroelectric and flow transport capacity. There are two cases occurring in a dam: 1 the dam upstream has a reduction of velocity and it start a process of sedimentation that will accelerate its siltation and reducing its useful life, 2 dam downstream has water velocity again and then initiate erosion process due the lack of sediments in the liquid mass. It can be concluded that changes of use and occupation of land in the watershed generate increased occurrence of peak flow and sediment transport, but the inadequate management of the area (with removal of riparian vegetation and lack of energy sinks in outputs of drainage systems potentiates the increasing the instability of water bodies morphology. In case of presence of reservoirs, the alterations are worst because they create siltation and erosion process at the same river.

  5. Multi-Objective Flexible Flow Shop Scheduling Problem Considering Variable Processing Time due to Renewable Energy

    Directory of Open Access Journals (Sweden)

    Xiuli Wu

    2018-03-01

    Full Text Available Renewable energy is an alternative to non-renewable energy to reduce the carbon footprint of manufacturing systems. Finding out how to make an alternative energy-efficient scheduling solution when renewable and non-renewable energy drives production is of great importance. In this paper, a multi-objective flexible flow shop scheduling problem that considers variable processing time due to renewable energy (MFFSP-VPTRE is studied. First, the optimization model of the MFFSP-VPTRE is formulated considering the periodicity of renewable energy and the limitations of energy storage capacity. Then, a hybrid non-dominated sorting genetic algorithm with variable local search (HNSGA-II is proposed to solve the MFFSP-VPTRE. An operation and machine-based encoding method is employed. A low-carbon scheduling algorithm is presented. Besides the crossover and mutation, a variable local search is used to improve the offspring’s Pareto set. The offspring and the parents are combined and those that dominate more are selected to continue evolving. Finally, two groups of experiments are carried out. The results show that the low-carbon scheduling algorithm can effectively reduce the carbon footprint under the premise of makespan optimization and the HNSGA-II outperforms the traditional NSGA-II and can solve the MFFSP-VPTRE effectively and efficiently.

  6. Inorganic Surface Coating with Fast Wetting-Dewetting Transitions for Liquid Manipulations.

    Science.gov (United States)

    Yang, Yajie; Zhang, Liaoliao; Wang, Jue; Wang, Xinwei; Duan, Libing; Wang, Nan; Xiao, Fajun; Xie, Yanbo; Zhao, Jianlin

    2018-06-06

    Liquid manipulation is a fundamental issue for microfluidics and miniaturized sensors. Fast wetting-state transitions by optical methods have proven being efficient for liquid manipulations by organic surface coatings, however rarely been achieved by using inorganic coatings. Here, we report a fast optical-induced wetting-state transition surface achieved by inorganic coating, enabling tens of second transitions for a wetting-dewetting cycle, shortened from an hour, as typically reported. Here, we demonstrate a gravity-driven microfluidic reactor and switch it to a mixer after a second-step exposure in a minimum of within 80 s of UV exposure. The fast wetting-dewetting transition surfaces enable the fast switchable or erasable smart surfaces for water collection, miniature chemical reaction, or sensing systems by using inorganic surface coatings.

  7. Critical point dewetting: competition between the gravity and the dispersion force

    International Nuclear Information System (INIS)

    Ohmasa, Y; Takahashi, S; Fujii, K; Yao, M

    2008-01-01

    Near the critical temperature of an immiscible binary liquid system, a solid substrate is usually covered completely by one of the liquid phases. This phenomenon is called the 'critical point wetting , which is predicted by Cahn in 1977, and have been confirmed for many fluid systems experimentally. However, we found that liquid Se-Tl system on a quartz substrate does not show the critical point wetting near the liquid-liquid critical point. On a contrary, when the temperature goes down from the critical point, a Se-rich wetting film intrudes between the Tl-rich bulk liquid and the quartz wall. This result is a clear evidence of the 'critical point dewetting' phenomenon. It is suggested from a theoretical consideration that the critical point dewetting takes place as a result of the competition between the long-range dispersion force and the gravity

  8. Dewetting and spreading transitions for active matter on random pinning substrates.

    Science.gov (United States)

    Sándor, Cs; Libál, A; Reichhardt, C; Olson Reichhardt, C J

    2017-05-28

    We show that sterically interacting self-propelled disks in the presence of random pinning substrates exhibit transitions among a variety of different states. In particular, from a phase separated cluster state, the disks can spread out and homogeneously cover the substrate in what can be viewed as an example of an active matter wetting transition. We map the location of this transition as a function of activity, disk density, and substrate strength, and we also identify other phases including a cluster state, coexistence between a cluster and a labyrinth wetted phase, and a pinned liquid. Convenient measures of these phases include the cluster size, which dips at the wetting-dewetting transition, and the fraction of sixfold coordinated particles, which drops when dewetting occurs.

  9. A parametric finite element method for solid-state dewetting problems with anisotropic surface energies

    Science.gov (United States)

    Bao, Weizhu; Jiang, Wei; Wang, Yan; Zhao, Quan

    2017-02-01

    We propose an efficient and accurate parametric finite element method (PFEM) for solving sharp-interface continuum models for solid-state dewetting of thin films with anisotropic surface energies. The governing equations of the sharp-interface models belong to a new type of high-order (4th- or 6th-order) geometric evolution partial differential equations about open curve/surface interface tracking problems which include anisotropic surface diffusion flow and contact line migration. Compared to the traditional methods (e.g., marker-particle methods), the proposed PFEM not only has very good accuracy, but also poses very mild restrictions on the numerical stability, and thus it has significant advantages for solving this type of open curve evolution problems with applications in the simulation of solid-state dewetting. Extensive numerical results are reported to demonstrate the accuracy and high efficiency of the proposed PFEM.

  10. On the Internal Structure of Mobile Barchan Sand Dunes due to Granular Processes

    Science.gov (United States)

    Vriend, N. M.; Arran, M.; Louge, M. Y.; Hay, A. G.; Valance, A.

    2017-12-01

    In this work, we visualize the internal structure of mobile barchan desert dunes at the avalanche scale. We reveal an intriguing history of dune building using a novel combination of local sand sampling and advanced geophysical techniques resulting in high resolution measurements of individual avalanche events. Due to progressive rebuilding, granular avalanching, erosional and depositional processes, these marching barchan dunes are reworked every few years and a characteristic zebra-pattern (figure 1a), orientated parallel to the slipface at the angle of repose, appears at regular intervals. We present scientific data on the structure obtained from several mobile barchan dunes of different sizes during recent desert field campaigns (2014, 2015, 2017) in a mobile barchan dune field in Qatar (25.01°N, 51.34°E in the AlWakrah municipality). The site has been equipped with a weather station and has been regularly visited by a multidisciplinary research team in recent years (e.g. [1]). By applying high-frequency (1200 MHz) ground penetrating radar (GPR) transects across the midline (figure 1b) we map the continuous evolution of this cross-bedding at high resolution deep within the dune. The GPR reveals a slope reduction of the slipface near the base of the dune; evidence of irregular wind reversals; and the presence of a harder aeolian cap around the crest and extending to the brink. The data is supplemented with granulometry from layers stabilized by dyed water injection and uncovered by excavating vertical walls perpendicular to old buried avalanches. We attribute visible differences in water penetration between adjacent layers to fine particle segregation processes in granular avalanches. This work was made possible by the support of NPRP grant 6-059-2-023 from the Qatar National Research Fund to MYL and AGH, and a Royal Society Dorothy Hodgkin Research Fellowship to NMV. We thank Jean-Luc Métayer for performing detailed particle size distribution measurements

  11. Solid state dewetting and stress relaxation in a thin single crystalline Ni film on sapphire

    International Nuclear Information System (INIS)

    Rabkin, E.; Amram, D.; Alster, E.

    2014-01-01

    In this study, we deposited a 80 nm thick single crystalline Ni film on a sapphire substrate. Heat treatment of this film at 1000 °C followed by slow cooling resulted in the formation of faceted holes, star-like channel instabilities and faceted microwires. The ridges at the rims of faceted holes and channels exhibited a twinning orientation relationship with the rest of the film. A sub-nanometer-high hexagonal topography pattern on the surface of the unperturbed film was observed by atomic force microscopy. No such pattern was observed on the top facets of isolated Ni particles and hole ridges. We discuss the observed dewetting patterns in terms of the effects of Ni surface anisotropy and faceting on solid state dewetting. The hexagonal pattern on the surface of the unperturbed film was attributed to thermal stress relaxation in the film via dislocations glide. This work demonstrates that solid state dewetting of single crystalline metal films can be utilized for film patterning and for producing hierarchical surface topographies

  12. Dewetting of thin films on flexible substrates via direct-write laser exposure

    Science.gov (United States)

    Ferrer, Anthony Jesus

    Microelectromechanical systems (MEMS) have enabled a wide variety of technologies both in the consumer space and in industrial/research areas. At the market level, such devices advance by the invention and innovation of production techniques. Additionally, there has been increased demand for flexible versions of such MEMS devices. Thin film patterning, represents a key technology for the realization of such flexible electronics. Patterns and methods that can be directly written into the thin film allow for design modification on the fly with the need for harsh chemicals and long etching steps. Laser-induced dewetting has the potential to create patterns in thin films at both the microscopic and nanoscopic level without wasting deposited material. This thesis presents the first demonstration of high-speed direct-write patterning of metallic thin films that uses a laser-induced dewetting phenomenon to prevent material loss. The ability to build film material with this technique is explored using various scanning geometries. Finally, demonstrations of direct-write dewetting of a variety of thin films will be presented with special consideration for high melting point metals deposited upon polymer substrates.

  13. Self-organized morphological evolution and dewetting in solvent vapor annealing of spin coated polymer blend nanostructures.

    Science.gov (United States)

    Roy, Sudeshna; Sharma, Ashutosh

    2015-07-01

    Dewetting pathways, kinetics and morphologies of thin films of phase separating polymer blends are governed by the relative mobilities of the two components. We characterize the morphological transformations of the nanostructures of a PS/PMMA blend by annealing in toluene and chloroform vapors. Toluene leads to faster reorganization of PS, whereas chloroform engenders the opposite effect. Spin coating produces a very rough PMMA rich layer that completely wets the substrate and forms a plethora of slender columns protruding through the continuous PS rich layer on top. The nanostructures were stable under long thermal annealing but in the vapor annealing, phase separation and dewetting occurred readily to form the equilibrium structures of dewetted droplets of PS on top of PMMA which also climbed around the PS droplets to form rims. Toluene and chloroform annealing required around 50 h and 1 h respectively to attain the equilibrium. Substantial differences are observed in the intermediate morphologies (heights of nanostructures, roughness and size). PMMA columns remained embedded in the dewetted PS droplets, whereas a high mobility of PMMA in chloroform allowed its rapid evacuation during dewetting to produce an intermediate swiss-cheese like morphology of PS domains. Copyright © 2015 Elsevier Inc. All rights reserved.

  14. Heterogeneity of glucagonomas due to differential processing of proglucagon-derived peptides

    DEFF Research Database (Denmark)

    Challis, Benjamin G; Albrechtsen, Nicolai J Wewer; Bansiya, Vishakha

    2015-01-01

    activities including critical roles in glucose and amino acid metabolism, energy homeostasis and gastrointestinal physiology.The clinical manifestations of proglucagon-expressing tumours may exhibit marked phenotypic variation due to the biochemical heterogeneity of their secreted peptide repertoire...... the rash. Case 2, a 48-year-old male presented with diabetes mellitus, diarrhoea, weight loss, nausea, vomiting and perineal rash due to a grade 1 metastatic pNET and hyperglucagonaemia. In both cases, plasma levels of all measured PGDPs were elevated and attenuated following SSA therapy. In case 1...

  15. Equilibrium positions due to different cooling processes in superconducting levitation systems

    International Nuclear Information System (INIS)

    Navau, C; Sanchez, A; Pardo, E; Chen, D-X

    2004-01-01

    The equilibrium position of a superconducting levitation device is determined not only by the geometry and electromagnetic properties of its components, but also by the cooling process of the superconductor. In this work we study the dependence of the equilibrium positions upon the cooling process by introducing diagrams of a new kind which display the different possibilities for a given levitation system. Using the critical state model and the principle of magnetic energy, we calculate different diagrams of this type for the case of a cylindrically symmetric permanent magnet-superconductor system. The results allow us to find out, for a given levitation system, which cooling process improves the capabilities of the system

  16. Structure Formation of Ultrathin PEO Films at Solid Interfaces—Complex Pattern Formation by Dewetting and Crystallization

    Directory of Open Access Journals (Sweden)

    Hans-Georg Braun

    2013-02-01

    Full Text Available The direct contact of ultrathin polymer films with a solid substrate may result in thin film rupture caused by dewetting. With crystallisable polymers such as polyethyleneoxide (PEO, molecular self-assembly into partial ordered lamella structures is studied as an additional source of pattern formation. Morphological features in ultrathin PEO films (thickness < 10 nm result from an interplay between dewetting patterns and diffusion limited growth pattern of ordered lamella growing within the dewetting areas. Besides structure formation of hydrophilic PEO molecules, n-alkylterminated (hydrophobic PEO oligomers are investigated with respect to self-organization in ultrathin films. Morphological features characteristic for pure PEO are not changed by the presence of the n-alkylgroups.

  17. Evaluation of consequence due to higher hydrazine content in partitioning stream of PUREX process

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, K. Suresh [Bhabha Atomic Research Centre, Mumbai (India). Special Nuclear Recycle Facility

    2016-07-01

    Hydrazine nitrate is being used as a stabilizer for U(IV) as well as Pu(III) during partitioning of Pu in PUREX process by scavenging the nitrous acid present along with nitric acid. As hydrazine hydrate as well as its salts have been successfully used for scrubbing of degradation products of TBP to aqueous phase, experiments were conducted to evaluate the consequence of hydrazine content during Pu partitioning. It was observed that higher amount of hydrazine nitrate along with uranous nitrate in the partitioning stream of PUREX process leads to build up of DBP in aqueous phase and resulted in precipitation of Pu.

  18. Estimation of the Past and Future Infrastructure Damage Due the Permafrost Evolution Processes

    Science.gov (United States)

    Sergeev, D. O.; Chesnokova, I. V.; Morozova, A. V.

    2015-12-01

    The geocryological processes such as thermokarst, frost heaving and fracturing, icing, thermal erosion are the source of immediate danger for the structures. The economic losses during the construction procedures in the permafrost area are linked also with the other geological processes that have the specific character in cold regions. These processes are swamping, desertification, deflation, flooding, mudflows and landslides. Linear transport structures are most vulnerable component of regional and national economy. Because the high length the transport structures have to cross the landscapes with different permafrost conditions that have the different reaction to climate change. The climate warming is favorable for thermokarst and the frost heaving is linked with climate cooling. In result the structure falls in the circumstances that are not predicted in the construction project. Local engineering problems of structure exploitation lead to global risks of sustainable development of regions. Authors developed the database of geocryological damage cases for the last twelve years at the Russian territory. Spatial data have the attributive table that was filled by the published information from various permafrost conference proceedings. The preliminary GIS-analysis of gathered data showed the widespread territorial distribution of the cases of negative consequences of geocryological processes activity. The information about maximum effect from geocryological processes was validated by detailed field investigation along the railways in Yamal and Transbaicalia Regions. Authors expect the expanding of database by similar data from other sectors of Arctic. It is important for analyzing the regional, time and industrial tendencies of geocryological risk evolution. Obtained information could be used in insurance procedures and in information systems of decisions support in different management levels. The investigation was completed with financial support by Russian

  19. Crystallographic analysis of the solid-state dewetting of polycrystalline gold film using automated indexing in a transmission electron microscope

    Directory of Open Access Journals (Sweden)

    S. A. Jang

    2015-12-01

    Full Text Available We analyzed the effect of crystallographic anisotropy on the morphological evolution of a 12-nm-thick gold film during solid-state dewetting at high temperatures using automated indexing tool in a transmission electron microscopy. Dewetting initiated at grain-boundary triple junctions adjacent to large grains resulting from abnormal grain growth driven by (111 texture development. Voids at the junctions developed shapes with faceted edges bounded by low-index crystal planes. The kinetic mobility of the edges varied with the crystal orientation normal to the edges, with a predominance of specific edges with the slowest retraction rates as the annealing time was increased.

  20. Crystallographic analysis of the solid-state dewetting of polycrystalline gold film using automated indexing in a transmission electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Jang, S. A.; Lee, H. J.; Oh, Y. J., E-mail: yjoh@hanbat.ac.kr [Department of Advanced Materials Science and Engineering, Hanbat National University, 125, Dongseo-daero, Yuseong-gu, Daejeon 305-719 (Korea, Republic of); Thompson, C. V.; Ross, C. A., E-mail: caross@mit.edu [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2015-12-01

    We analyzed the effect of crystallographic anisotropy on the morphological evolution of a 12-nm-thick gold film during solid-state dewetting at high temperatures using automated indexing tool in a transmission electron microscopy. Dewetting initiated at grain-boundary triple junctions adjacent to large grains resulting from abnormal grain growth driven by (111) texture development. Voids at the junctions developed shapes with faceted edges bounded by low-index crystal planes. The kinetic mobility of the edges varied with the crystal orientation normal to the edges, with a predominance of specific edges with the slowest retraction rates as the annealing time was increased.

  1. Due Process in Dual Process: Model-Recovery Simulations of Decision-Bound Strategy Analysis in Category Learning

    Science.gov (United States)

    Edmunds, Charlotte E. R.; Milton, Fraser; Wills, Andy J.

    2018-01-01

    Behavioral evidence for the COVIS dual-process model of category learning has been widely reported in over a hundred publications (Ashby & Valentin, 2016). It is generally accepted that the validity of such evidence depends on the accurate identification of individual participants' categorization strategies, a task that usually falls to…

  2. Anomalous scaling due to correlations: limit theorems and self-similar processes

    International Nuclear Information System (INIS)

    Stella, Attilio L; Baldovin, Fulvio

    2010-01-01

    We derive theorems which outline explicit mechanisms by which anomalous scaling for the probability density function of the sum of many correlated random variables asymptotically prevails. The results characterize general anomalous scaling forms, explain their universal character, and specify universality domains in the spaces of joint probability density functions of the summand variables. These density functions are assumed to be invariant under arbitrary permutations of their arguments. Examples from the theory of critical phenomena are discussed. The novel notion of stability implied by the limit theorems also allows us to define sequences of random variables whose sum satisfies anomalous scaling for any finite number of summands. If regarded as developing in time, the stochastic processes described by these variables are non-Markovian generalizations of Gaussian processes with uncorrelated increments, and provide, e.g., explicit realizations of a recently proposed model of index evolution in finance

  3. Maximum Lateness Scheduling on Two-Person Cooperative Games with Variable Processing Times and Common Due Date

    OpenAIRE

    Liu, Peng; Wang, Xiaoli

    2017-01-01

    A new maximum lateness scheduling model in which both cooperative games and variable processing times exist simultaneously is considered in this paper. The job variable processing time is described by an increasing or a decreasing function dependent on the position of a job in the sequence. Two persons have to cooperate in order to process a set of jobs. Each of them has a single machine and their processing cost is defined as the minimum value of maximum lateness. All jobs have a common due ...

  4. Impact of residual by-products from tungsten film deposition on process integration due to nonuniformity of the tungsten film

    CERN Document Server

    Sidhwa, A; Gandy, T; Melosky, S; Brown, W; Ang, S; Naseem, H; Ulrich, R

    2002-01-01

    The effects of residual by products from a tungsten film deposition process and their impact on process integration due to the nonuniformity of the tungsten film were investigated in this work. The tungsten film deposition process involves three steps: nucleation, stabilization, and tungsten bulk fill. Six experiments were conducted in search for a solution to the problem. The resulting data suggest that excess nitrogen left in the chamber following the tungsten nucleation step, along with residual by products, causes a shift in the tungsten film uniformity during the tungsten bulk fill process. Data reveal that, due to the residual by products, an abnormal grain growth occurs causing a variation in the tungsten thickness across the wafer during the bulk fill step. Although several possible solutions were revealed by the experiments, potential integration problems limited the acceptable solutions to one. The solution chosen was the introduction of a 10 s pumpdown immediately following the nucleation step. Thi...

  5. Solid-state dewetting and island morphologies in strongly anisotropic materials

    International Nuclear Information System (INIS)

    Jiang, Wei; Wang, Yan; Zhao, Quan; Srolovitz, David J.; Bao, Weizhu

    2016-01-01

    We propose a sharp-interface continuum model based on a thermodynamic variational approach to investigate the strong anisotropic effect on solid-state dewetting including contact line dynamics. For sufficiently strong surface energy anisotropy, we show that multiple equilibrium shapes may appear that cannot be described by the widely employed Winterbottom construction, i.e., the modified Wulff construction for an island on a substrate. We repair the Winterbottom construction to include multiple equilibrium shapes and employ our evolution model to demonstrate that all such shapes are dynamically accessible.

  6. Dynamic Chemically Driven Dewetting, Spreading, and Self-Running of Sessile Droplets on Crystalline Silicon.

    Science.gov (United States)

    Arscott, Steve

    2016-12-06

    A chemically driven dewetting effect is demonstrated using sessile droplets of dilute hydrofluoric acid on chemically oxidized silicon wafers. The dewetting occurs as the thin oxide is slowly etched by the droplet and replaced by a hydrogen-terminated surface; the result of this is a gradual increase in the contact angle of the droplet with time. The time-varying work of adhesion is calculated from the time-varying contact angle; this corresponds to the changing chemical nature of the surface during dewetting and can be modeled by the well-known logistic (sigmoid) function often used for the modeling of restricted growth, in this case, the transition from an oxidized surface to a hydrogen-terminated silicon surface. The observation of the time-varying contact angle allows one to both measure the etch rate of the silicon oxide and estimate the hydrogenation rate as a function of HF concentration and wafer type. In addition to this, at a certain HF concentration, a self-running droplet effect is observed. In contrast, on hydrogen-terminated silicon wafers, a chemically induced spreading effect is observed using sessile droplets of nitric acid. The droplet spreading can also be modeled using a logistical function, where the restricted growth is the transition from hydrogen-terminated to a chemically induced oxidized silicon surface. The chemically driven dewetting and spreading observed here add to the methods available to study dynamic wetting (e.g., the moving three-phase contact line) of sessile droplets on surfaces. By slowing down chemical kinetics of the wetting, one is able to record the changing profile of the sessile droplet with time and gather information concerning the time-varying surface chemistry. The data also indicates a chemical interface hysteresis (CIH) that is compared to contact angle hysteresis (CAH). The approach can also be used to study the chemical etching and deposition behavior of thin films using liquids by monitoring the macroscopic

  7. Importance of dewetting in organic molecular-beam deposition: Pentacene on gold

    International Nuclear Information System (INIS)

    Beernink, G.; Strunskus, T.; Witte, G.; Woell, Ch.

    2004-01-01

    Organic molecular-beam deposition of pentacene on gold substrates has been investigated using a multitechnique approach. The morphology of the organic thin films depends strongly on the substrate temperature. Pronounced dewetting and island formation are observed at room temperature. Whereas pentacene molecules adopt a planar monolayer structure, they continue to grow in an upright orientation in multilayer films as inferred from x-ray absorption spectroscopy and atomic force microscopy. These results are in pronounced contrast to a recent scanning tunneling microscopy (STM) study by Kang and Zhu [Appl. Phys. Lett. 82, 3248 (2003)] and indicate fundamental problems in the interpretation of STM measurements for organic thin films

  8. Mimicking the stenocara beetle--dewetting of drops from a patterned superhydrophobic surface.

    Science.gov (United States)

    Dorrer, Christian; Rühe, Jürgen

    2008-06-17

    This paper describes the preparation of superhydrophobic surfaces that have been selectively patterned with circular hydrophilic domains. These materials mimicked the back of the stenocara beetle and collected drops of water if exposed to mist or fog. Under the effect of gravity, the drops dewetted from the hydrophilic regions once a critical volume had been reached. The surface energy in the hydrophilic regions was carefully controlled and assumed various values, allowing us to study the behavior of drops as a function of the superhydrophobic/hydrophilic contrast. We have investigated the development of drops and quantitatively analyzed the critical volumes as a function of several parameters.

  9. Torque strength of an endplate welding due to process parameters using a fuel assembling welder

    Energy Technology Data Exchange (ETDEWEB)

    Koo, Dae-Seo; Kim, Soo-Sung [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2008-05-15

    As fuel bundles in a PHWR core irradiated, inner pressure in the claddings of the fuel rods increases owing to the outer pressure and fission products of the nuclear fissions. Because of a leak possibility from a welding between a cladding and end plug, this welding part is connected with the safety of nuclear fuel rods. Endplug-cladding welding of nuclear fuel rods in a PHWR takes advantage of a resistance upset butt welding. The weldment between a cladding and endplug is to be sound to prevent a leakage of fission products from a cladding as a UO{sub 2} pellet is irradiated. Weld flash was made from a deformation due to a welding heat and increasing the pressure of the resistivity and resistance from a cladding and endplug. Weld line of a welding interface, microstructure of a weldment and a crystallographic structure change were sources of an iodine induced SCC in a reactor. The soundness of a weldment is important because a weld line connects the leakage of fission products from an operational reactor. In this study, welding specimens were fabricated by a resistance welding method using a bundle fuel welder to measure and analyze the torque of an endplug-endplate welding. The torque of a weldment between an endplug and endplate was measured and analyzed with the welding time. The weldability of a weldment between an endplug and endplate was investigated by a metallographic examination.

  10. Solid-state dewetting of single- and bilayer Au-W thin films: Unraveling the role of individual layer thickness, stacking sequence and oxidation on morphology evolution

    Directory of Open Access Journals (Sweden)

    A. Herz

    2016-03-01

    Full Text Available Self-assembly of ultrathin Au, W, and Au-W bilayer thin films is investigated using a rapid thermal annealing technique in an inert ambient. The solid-state dewetting of Au films is briefly revisited in order to emphasize the role of initial film thickness. W films deposited onto SiO2 evolve into needle-like nanocrystals rather than forming particle-like agglomerates upon annealing at elevated temperatures. Transmission electron microscopy reveals that such nanocrystals actually consist of tungsten (VI oxide (WO3 which is related to an anisotropic oxide crystal growth out of the thin film. The evolution of W films is highly sensitive to the presence of any residual oxygen. Combination of both the dewetting of Au and the oxide crystal growth of WO3 is realized by using various bilayer film configurations of the immiscible Au and W. At low temperature, Au dewetting is initiated while oxide crystal growth is still suppressed. Depending on the stacking sequence of the Au-W bilayer thin film, W acts either as a substrate or as a passivation layer for the dewetting of Au. Being the ground layer, W changes the wettability of Au which clearly modifies its initial state for the dewetting. Being the top layer, W prevents Au from dewetting regardless of Au film thickness. Moreover, regular pattern formation of Au-WO3 nanoparticles is observed at high temperature demonstrating how bilayer thin film dewetting can create unique nanostructure arrangements.

  11. Solid-state dewetting of single- and bilayer Au-W thin films: Unraveling the role of individual layer thickness, stacking sequence and oxidation on morphology evolution

    Energy Technology Data Exchange (ETDEWEB)

    Herz, A., E-mail: andreas.herz@tu-ilmenau.de, E-mail: dong.wang@tu-ilmenau.de; Franz, A.; Theska, F.; Hentschel, M.; Kups, Th.; Wang, D., E-mail: andreas.herz@tu-ilmenau.de, E-mail: dong.wang@tu-ilmenau.de; Schaaf, P. [Department of Materials for Electronics and Electrical Engineering, Institute of Materials Science and Engineering and Institute of Micro- and Nanotechnologies MacroNano, TU Ilmenau, D-98693 Ilmenau (Germany)

    2016-03-15

    Self-assembly of ultrathin Au, W, and Au-W bilayer thin films is investigated using a rapid thermal annealing technique in an inert ambient. The solid-state dewetting of Au films is briefly revisited in order to emphasize the role of initial film thickness. W films deposited onto SiO{sub 2} evolve into needle-like nanocrystals rather than forming particle-like agglomerates upon annealing at elevated temperatures. Transmission electron microscopy reveals that such nanocrystals actually consist of tungsten (VI) oxide (WO{sub 3}) which is related to an anisotropic oxide crystal growth out of the thin film. The evolution of W films is highly sensitive to the presence of any residual oxygen. Combination of both the dewetting of Au and the oxide crystal growth of WO{sub 3} is realized by using various bilayer film configurations of the immiscible Au and W. At low temperature, Au dewetting is initiated while oxide crystal growth is still suppressed. Depending on the stacking sequence of the Au-W bilayer thin film, W acts either as a substrate or as a passivation layer for the dewetting of Au. Being the ground layer, W changes the wettability of Au which clearly modifies its initial state for the dewetting. Being the top layer, W prevents Au from dewetting regardless of Au film thickness. Moreover, regular pattern formation of Au-WO{sub 3} nanoparticles is observed at high temperature demonstrating how bilayer thin film dewetting can create unique nanostructure arrangements.

  12. Limitations Of The Current State Space Modelling Approach In Multistage Machining Processes Due To Operation Variations

    Science.gov (United States)

    Abellán-Nebot, J. V.; Liu, J.; Romero, F.

    2009-11-01

    The State Space modelling approach has been recently proposed as an engineering-driven technique for part quality prediction in Multistage Machining Processes (MMP). Current State Space models incorporate fixture and datum variations in the multi-stage variation propagation, without explicitly considering common operation variations such as machine-tool thermal distortions, cutting-tool wear, cutting-tool deflections, etc. This paper shows the limitations of the current State Space model through an experimental case study where the effect of the spindle thermal expansion, cutting-tool flank wear and locator errors are introduced. The paper also discusses the extension of the current State Space model to include operation variations and its potential benefits.

  13. Clarifying Cutting and Sewing Processes with Due Windows Using an Effective Ant Colony Optimization

    Directory of Open Access Journals (Sweden)

    Rong-Hwa Huang

    2013-01-01

    Full Text Available The cutting and sewing process is a traditional flow shop scheduling problem in the real world. This two-stage flexible flow shop is often commonly associated with manufacturing in the fashion and textiles industry. Many investigations have demonstrated that the ant colony optimization (ACO algorithm is effective and efficient for solving scheduling problems. This work applies a novel effective ant colony optimization (EACO algorithm to solve two-stage flexible flow shop scheduling problems and thereby minimize earliness, tardiness, and makespan. Computational results reveal that for both small and large problems, EACO is more effective and robust than both the particle swarm optimization (PSO algorithm and the ACO algorithm. Importantly, this work demonstrates that EACO can solve complex scheduling problems in an acceptable period of time.

  14. Physical quality characteristics of the microwave-dried breadfruit powders due to different processing conditions

    Science.gov (United States)

    Taruna, I.; Hakim, A. L.; Sutarsi

    2018-03-01

    Production of breadfruit powder has been an option to make easy its uses in various food processing. Accordingly, there is a need recently to apply advanced drying method, i.e. microwave drying, for improving quality since conventional methods produced highly variable product quality and required longer process. The present work was aimed to study the effect of microwave power and grinding time on physical quality of breadfruit powders. The experiment was done initially by drying breadfruit slices in a microwave dryer at power level of 420, 540, and 720 W and then grinding for 3, 5, and 7 min to get powdery product of less than 80 mesh. The physical quality of breadfruit powders were measured in terms of fineness modulus (FM), average particle size (D), whiteness (WI), total color difference (ΔE), water absorption (Wa), oil absorption (La), bulk density (ρb) and consistency gel (Gc). The results showed that physical quality of powders and its ranged-values included the FM (2.08-2.62), D (0.44-0.68 mm), WI (75.2-77.9), ΔE (7.4-10.5), Wa (5.5-6.2 ml/g), La (0.7-0.9 ml/g), ρb (0.62-0.70 g/cm3) and Gc (41.3-46.8 mm). The experiment revealed that variation of microwave power and grinding time affected significantly the quality of the breadfruit powders. However, microwave power was more dominant factor to affect quality of breadfruit powder in comparison to the grinding time.

  15. Enhancing Title Ix Due Process Standards in Campus Sexual Assault Adjudication: Considering the Roles of Distributive, Procedural, and Restorative Justice

    Science.gov (United States)

    Harper, Shannon; Maskaly, Jon; Kirkner, Anne; Lorenz, Katherine

    2017-01-01

    Title IX prohibits sex discrimination--including sexual assault--in higher education. The Department of Education Office for Civil Rights' 2011 "Dear Colleague Letter" outlines recommendations for campus sexual assault adjudication allowing a variety of procedures that fail to protect accused students' due process rights and victims'…

  16. Home-Schools and Interscholastic Sports: Denying Participation Violates United States Constitutional Due Process and Equal Protection Rights. Chalk Talk.

    Science.gov (United States)

    Webb, Derwin L.

    1997-01-01

    Participation in sports, in some instances, is considered a right which grants students the opportunity to be involved in extracurricular activities. Discusses the potential violation of home-schooled students' constitutional due process and equal protection rights and the pertinent laws regarding students and their ability to participate in…

  17. Single Machine Scheduling and Due Date Assignment with Past-Sequence-Dependent Setup Time and Position-Dependent Processing Time

    Directory of Open Access Journals (Sweden)

    Chuan-Li Zhao

    2014-01-01

    Full Text Available This paper considers single machine scheduling and due date assignment with setup time. The setup time is proportional to the length of the already processed jobs; that is, the setup time is past-sequence-dependent (p-s-d. It is assumed that a job's processing time depends on its position in a sequence. The objective functions include total earliness, the weighted number of tardy jobs, and the cost of due date assignment. We analyze these problems with two different due date assignment methods. We first consider the model with job-dependent position effects. For each case, by converting the problem to a series of assignment problems, we proved that the problems can be solved in On4 time. For the model with job-independent position effects, we proved that the problems can be solved in On3 time by providing a dynamic programming algorithm.

  18. Modeling deformation processes of salt caverns for gas storage due to fluctuating operation pressures

    Science.gov (United States)

    Böttcher, N.; Nagel, T.; Goerke, U.; Khaledi, K.; Lins, Y.; König, D.; Schanz, T.; Köhn, D.; Attia, S.; Rabbel, W.; Bauer, S.; Kolditz, O.

    2013-12-01

    In the course of the Energy Transition in Germany, the focus of the country's energy sources is shifting from fossil to renewable and sustainable energy carriers. Since renewable energy sources, such as wind and solar power, are subjected to annual, seasonal, and diurnal fluctuations, the development and extension of energy storage capacities is a priority in German R&D programs. Common methods of energy storage are the utilization of subsurface caverns as a reservoir for natural or artificial fuel gases, such as hydrogen, methane, or the storage of compressed air. The construction of caverns in salt rock is inexpensive in comparison to solid rock formations due to the possibility of solution mining. Another advantage of evaporite as a host material is the self-healing capacity of salt rock. Gas caverns are capable of short-term energy storage (hours to days), so the operating pressures inside the caverns are fluctuating periodically with a high number of cycles. This work investigates the influence of fluctuating operation pressures on the stability of the host rock of gas storage caverns utilizing numerical models. Therefore, we developed a coupled Thermo-Hydro-Mechanical (THM) model based on the finite element method utilizing the open-source software platform OpenGeoSys. Our simulations include the thermodynamic behaviour of the gas during the loading/ unloading of the cavern. This provides information on the transient pressure and temperature distribution on the cavern boundary to calculate the deformation of its geometry. Non-linear material models are used for the mechanical analysis, which describe the creep and self-healing behavior of the salt rock under fluctuating loading pressures. In order to identify the necessary material parameters, we perform experimental studies on the mechanical behaviour of salt rock under varying pressure and temperature conditions. Based on the numerical results, we further derive concepts for monitoring THM quantities in the

  19. Simulation of the charging process of the LISA test masses due to solar flares

    International Nuclear Information System (INIS)

    Vocca, H; Grimani, C; Amico, P; Bosi, L; Marchesoni, F; Punturo, M; Travasso, F; Barone, M; Stanga, R; Vetrano, F; Vicere, A

    2004-01-01

    Cosmic-ray and solar high energy particles penetrate the LISA experiment test masses. Consequently, an electric charge accumulates in the bodies of the masses, generating spurious Coulomb forces between the masses and the surrounding electrodes. This process increases the noise level of the experiment. We have estimated the amount of charge deposited per second on the LISA test masses by solar flares and primary cosmic-ray protons at solar minimum. The simulation has been carried out with the Fluka Monte Carlo program. A simplified geometry for the experiment has been considered. We have found a net charging rate of 37 ± 1 e + /s for primary protons at solar minimum between 0.1 and 1000 GeV/n. The amount of charge released by a medium-strong solar flare, like that of 16 February 1984, is 10 732 ± 30 e + /s in the energy range 0.1-10 GeV/n. This value increases or decreases by approximately one order of magnitude for strong (weak) solar flares

  20. Interfacial reaction between SiC and aluminium due to extrusion and heat treatment process

    International Nuclear Information System (INIS)

    Junaidah Jai; Fauzi Ismail; Samsiah Sulaiman; Patthi Hussain, Azmi Idris; Yoichi Murakoshi

    1999-01-01

    Chemical interaction between aluminium (Al) and silicon carbide (SiC) produces aluminium carbide (Al 4 C 3 ) which presents potential problems in the production and application of Al/SiC Metal Matrix Composit (MMC). The Al 4 C 3 formed can reduce material properties such as strength in the MMC. This research work investigates the interface reaction in Al 7075/SiC MMC made through hot extrusion process. Mixed Al 7075/SiC MMC powders were pressed at 300 degree C and extruded at 500 degree C, with a reduction ratio of 20:1. The extruded MMC was then heat-treated in air at various temperatures from 560 degree C, 600 degree C, 640 degree C, 700 degree C to 800 degree C in order to observe the interface reaction of the MMC materials. The heat-treated MMCs were then analyzed under the optical microscope, X-ray Diffraction (XRD) Spectroscope and Scanning Electron Microscope (SEM) with Energy Dispersive X-ray (EDAZ) attachment to observe the interface reaction within the MMCs. This investigation confirms there was interface reaction between SiC and aluminium

  1. Characterization of ultrathin insulators in CMOS technology: Wearout and failure mechanisms due to processing and operation

    Science.gov (United States)

    Okandan, Murat

    In the CMOS technology the gate dielectric is the most critical layer, as its condition directly dictates the ultimate performance of the devices. In this thesis, the wear-out and failure mechanisms in ultra-thin (around 50A and lower) oxides are investigated. A new degradation phenomenon, quasi-breakdown (or soft-breakdown), and the annealing and stressing behavior of devices after quasi-breakdown are considered in detail. Devices that are in quasi-breakdown continue to operate as switches, but the gate leakage current is two orders of magnitude higher than the leakage in healthy devices and the stressing/annealing behavior of the devices are completely altered. This phenomenon is of utmost interest, since the reduction in SiO2 dielectric thickness has reached its physical limits, and the quasi-breakdown behavior is seen to dominate as a failure mode in this regime. The quasi-breakdown condition can be brought on by stresses during operation or processing. To further study this evolution through stresses and anneals, cyclic current-voltage (I-V) measurement has been further developed and utilized in this thesis. Cyclic IV is a simple and fast, two terminal measurement technique that looks at the transient current flowing in an MOS system during voltage sweeps from accumulation to inversion and back. During these sweeps, carrier trapping/detrapping, generation and recombination are observed. An experimental setup using a fast electrometer and analog to digital conversion (A/D) card and the software for control of the setup and data analysis were also developed to gain further insight into the detailed physics involved. Overall, the crucial aspects of wear-out and quasi-breakdown of ultrathin dielectrics, along with the methods for analyzing this evolution are presented in this thesis.

  2. Progressive softening of brittle-ductile transition due to interplay between chemical and deformation processes

    Science.gov (United States)

    Jeřábek, Petr; Bukovská, Zita; Morales, Luiz F. G.

    2017-04-01

    The micro-scale shear zones (shear bands) in granitoids from the South Armorican Shear Zone reflect localization of deformation and progressive weakening in the conditions of brittle-ductile transition. We studied microstructures in the shear bands with the aim to establish their P-T conditions and to derive stress and strain rates for specific deformation mechanisms. The evolving microstructure within shear bands documents switches in deformation mechanisms related to positive feedbacks between deformation and chemical processes and imposes mechanical constraints on the evolution of the brittle-ductile transition in the continental transform fault domains. The metamorphic mineral assemblage present in the shear bands indicate their formation at 300-350 ˚ C and 100-400 MPa. Focusing on the early development of shear bands, we identified three stages of shear band evolution. The early stage I associated with initiation of shear bands occurs via formation of microcracks with possible yielding differential stress of up to 250 MPa (Diamond and Tarantola, 2015). Stage II is associated with subgrain rotation recrystallization and dislocation creep in quartz and coeval dissolution-precipitation creep of microcline. Recrystallized quartz grains in shear bands show continual increase in size, and decrease in stress and strain rates from 94 MPa to 17-26 MPa (Stipp and Tullis, 2003) and 3.8*10-12 s-1- 1.8*10-14 s-1 (Patterson and Luan, 1990) associated with deformation partitioning into weaker microcline layer and shear band widening. The quartz mechanical data allowed us to set some constrains for coeval dissolution-precipitation of microcline which at our estimated P-T conditions suggests creep at 17-26 MPa differential stress and 3.8*10-13 s-1 strain rate. Stage III is characterized by localized slip along interconnected white mica bands accommodated by dislocation creep at strain rate 3.8*10-12 s-1 and stress 9.36 MPa (Mares and Kronenberg, 1993). The studied example

  3. Dewetting and adsorption in homopolymer films containing triblock copolymers: role of chain architecture and anchoring block molar fraction

    Czech Academy of Sciences Publication Activity Database

    Costa, A. C.; Composto, R. J.; Vlček, Petr; Morera, S.

    2005-01-01

    Roč. 81, 7-8 (2005), s. 683-698 ISSN 0021-8464 Institutional research plan: CEZ:AV0Z40500505 Keywords : adhesion * dewetting * forward recoil spectrometry Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.128, year: 2005

  4. Graphene Oxide Monolayer as a Compatibilizer at the Polymer-Polymer Interface for Stabilizing Polymer Bilayer Films against Dewetting.

    Science.gov (United States)

    Kim, Tae-Ho; Kim, Hyeri; Choi, Ki-In; Yoo, Jeseung; Seo, Young-Soo; Lee, Jeong-Soo; Koo, Jaseung

    2016-12-06

    We investigate the effect of adding graphene oxide (GO) sheets at the polymer-polymer interface on the dewetting dynamics and compatibility of immiscible polymer bilayer films. GO monolayers are deposited at the poly(methyl methacrylate) (PMMA)-polystyrene (PS) interface by the Langmuir-Schaefer technique. GO monolayers are found to significantly inhibit the dewetting behavior of both PMMA films (on PS substrates) and PS films (on PMMA substrates). This can be interpreted in terms of an interfacial interaction between the GO sheets and these polymers, which is evidenced by the reduced contact angle of the dewet droplets. The favorable interaction of GO with both PS and PMMA facilitates compatibilization of the immiscible polymer bilayer films, thereby stabilizing their bilayer films against dewetting. This compatibilization effect is verified by neutron reflectivity measurements, which reveal that the addition of GO monolayers broadens the interface between PS and the deuterated PMMA films by 2.2 times over that of the bilayer in the absence of GO.

  5. Phenomenological understanding of dewetting and embedding of noble metal nanoparticles in thin films induced by ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Prakash, Jai, E-mail: jai.gupta1983@gmail.com [Department of Chemistry, MMH College (Ch. Charan Singh University Meerut), Ghaiziabad 201001 (India); Chemical Physics of Materials, Université Libre de Bruxelles, Campus de la Plaine, CP 243, B-1050 Bruxelles (Belgium); Tripathi, A. [Inter University Accelerator Centre, Aruna Asif Ali Marg, New Delhi 110067 (India); Gautam, Sanjeev; Chae, K.H.; Song, Jonghan [Advanced Analysis Center, Korea Institute of Science and Technology, Seoul 136–791 (Korea, Republic of); Rigato, V. [INFN Laboratori Nazionali di Legnaro, Via Romea. 4, 35020 Legnaro, Padova (Italy); Tripathi, Jalaj [Department of Chemistry, MMH College (Ch. Charan Singh University Meerut), Ghaiziabad 201001 (India); Asokan, K. [Inter University Accelerator Centre, Aruna Asif Ali Marg, New Delhi 110067 (India)

    2014-10-15

    The present experimental work provides the phenomenological approach to understand the dewetting in thin noble metal films with subsequent formation of nanoparticles (NPs) and embedding of NPs induced by ion irradiation. Au/polyethyleneterepthlate (PET) bilayers were irradiated with 150 keV Ar ions at varying fluences and were studied using scanning electron microscopy (SEM) and cross-sectional transmission electron microscopy (X-TEM). Thin Au film begins to dewet from the substrate after irradiation and subsequent irradiation results in spherical nanoparticles on the surface that at a fluence of 5 × 10{sup 16} ions/cm{sup 2} become embedded into the substrate. In addition to dewetting in thin films, synthesis and embedding of metal NPs by ion irradiation, the present article explores fundamental thermodynamic principles that govern these events systematically under the effect of irradiation. The results are explained on the basis of ion induced sputtering, thermal spike inducing local melting and of thermodynamic driving forces by minimization of the system free energy where contributions of surface and interfacial energies are considered with subsequent ion induced viscous flow in substrate. - Highlights: • Phenomenological interpretation of dewetting and embedding of metal NPs in thin film. • Exploring fundamental thermodynamic principles under influence of ion irradiation. • Ion induced surface/interface microstructural changes using SEM/X-TEM. • Ion induced sputtering, thermal spike induced local melting. • Thermodynamic driving forces relate to surface and interfacial energies.

  6. Properties of three-dimensional structures prepared by Ge dewetting from Si(111) at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Shklyaev, Alexander, E-mail: shklyaev@isp.nsc.ru [A. V. Rzhanov Institute of Semiconductor Physics, SB RAS, Novosibirsk 630090 (Russian Federation); Novosibirsk State University, Novosibirsk 630090 (Russian Federation); Bolotov, Leonid; Poborchii, Vladimir; Tada, Tetsuya [National Institute of Advanced Industrial Science and Technology, Higashi 1-1-1, Tsukuba, Ibaraki 305-8562 (Japan)

    2015-05-28

    The formation of three-dimensional (3D) structures during Ge deposition on Si(111) at about 800 °C is studied with scanning tunneling, Kelvin probe and electron microscopies, and scanning tunneling and Raman spectroscopies. The observed surface morphology is formed by dewetting of Ge from Si(111), since it occurs mainly by means of minimization of surface and interfacial energies. The dewetting proceeds through massive Si eroding around growing 3D structures, providing them to be composed of SiGe with about a 30% Ge content, and leads to the significant reduction of the SiGe/Si interface area. It is found that the SiGe top component of 3D structures forms sharp interfaces with the underlying Si. The minimization of interfacial and strain energies occurs on the way that the 3D structures appear to get the dendrite-like shape. The Ge distribution in the 3D SiGe structures is inhomogeneous in the lateral dimension with a higher Ge concentration in their central areas and Ge segregation on their surface.

  7. Properties of three-dimensional structures prepared by Ge dewetting from Si(111) at high temperatures

    International Nuclear Information System (INIS)

    Shklyaev, Alexander; Bolotov, Leonid; Poborchii, Vladimir; Tada, Tetsuya

    2015-01-01

    The formation of three-dimensional (3D) structures during Ge deposition on Si(111) at about 800 °C is studied with scanning tunneling, Kelvin probe and electron microscopies, and scanning tunneling and Raman spectroscopies. The observed surface morphology is formed by dewetting of Ge from Si(111), since it occurs mainly by means of minimization of surface and interfacial energies. The dewetting proceeds through massive Si eroding around growing 3D structures, providing them to be composed of SiGe with about a 30% Ge content, and leads to the significant reduction of the SiGe/Si interface area. It is found that the SiGe top component of 3D structures forms sharp interfaces with the underlying Si. The minimization of interfacial and strain energies occurs on the way that the 3D structures appear to get the dendrite-like shape. The Ge distribution in the 3D SiGe structures is inhomogeneous in the lateral dimension with a higher Ge concentration in their central areas and Ge segregation on their surface

  8. Maximum Lateness Scheduling on Two-Person Cooperative Games with Variable Processing Times and Common Due Date

    Directory of Open Access Journals (Sweden)

    Peng Liu

    2017-01-01

    Full Text Available A new maximum lateness scheduling model in which both cooperative games and variable processing times exist simultaneously is considered in this paper. The job variable processing time is described by an increasing or a decreasing function dependent on the position of a job in the sequence. Two persons have to cooperate in order to process a set of jobs. Each of them has a single machine and their processing cost is defined as the minimum value of maximum lateness. All jobs have a common due date. The objective is to maximize the multiplication of their rational positive cooperative profits. A division of those jobs should be negotiated to yield a reasonable cooperative profit allocation scheme acceptable to them. We propose the sufficient and necessary conditions for the problems to have positive integer solution.

  9. Discipline and Due Process.

    Science.gov (United States)

    Collins, Mildred; Dowell, Mary L.

    1998-01-01

    Increasing numbers of parents do not accept a school's discipline policy and are refusing to permit their children to comply with disciplinary sanctions. According to the California Education Code, educators have the right to expect parents to accept disciplinary decisions made in compliance with required procedures. Parental defiance might worsen…

  10. Influence of predictive contamination to agricultural products due to dry and wet processes during an accidental release of radionuclides

    International Nuclear Information System (INIS)

    Hwang, Won Tae; Kim, Eun Han; Suh, Kyung Suk; Jeong, Hyo Joon; Han, Moon Hee; Lee, Chang Woo

    2003-01-01

    The influence of predictive contamination to agricultural products due to the wet processes as well as dry processes from radioactive air concentration during a nuclear emergency is comprehensively analyzed. The previous dynamic food chain model DYNACON considering Korean agricultural and environmental conditions, in which the initial input parameter was radionuclide concentrations on the ground, is improved so as to evaluate radioactive contamination to agricultural products from either radioactive air concentrations or radionuclide concentrations on the ground. As for the results, wet deposition is a more dominant mechanism than dry deposition in contamination on the ground. While, the contamination levels of agricultural products are strongly dependent on radionuclide and precipitation when the deposition of radionuclides occurs. It means that the contamination levels of agricultural products are determined from which is the more dominant process between deposition on the ground and interception to agricultural plants

  11. A novel in-vitro method for assessing contact lens surface dewetting: Non-invasive keratograph dry-up time (NIK-DUT).

    Science.gov (United States)

    Marx, Sebastian; Sickenberger, Wolfgang

    2017-12-01

    This study was designed to develop a novel technique called non-invasive keratograph dry-up time (NIK-DUT), which used an adapted corneal topographer, to analyse in-vitro contact lens surface dewetting and the effects of combinations of lenses and lens care solutions on dewetting. Variables were assessed to optimise sensitivity and reproducibility. To validate the method, in-vitro dewetting of silicone hydrogel contact lenses (balafilcon A, comfilcon A, lotrafilcon A, lotrafilcon B and senofilcon A) was tested. All lens types were soaked in OPTI-FREE ® PureMoist ® Multipurpose Disinfecting Solution (OFPM) and Sensitive Eyes ® Saline Solution. The mean NIK-DUT, defined as drying of 25% of the placido ring measurement segments (NIK-DUT_S25), was calculated for each lens/lens solution combination and a visual map constructed representing the time and location of the dry-up event. Optimal conditions for NIK-DUT measurement included mounting onto a glass stage with a surface geometry of r=8.5mm, e=0, and measuring with high intensity red or white illumination. This method detected significant differences in contact lens dewetting with different lens soaking solutions. NIK-DUT_S25 for all lenses was longer when pre-soaked in OFPM versus saline. Visual analysis showed that dewetting of contact lenses was not uniform across surfaces and differed between test solutions. NIK-DUT is suitable for detecting differences in dewetting among various contact lenses and lens-care combinations. NIK-DUT can quantify the dewetting of large areas of lens surfaces with little subjective influence. Lens care solutions containing surface-active wetting agents were found to delay surface dewetting of silicone hydrogel lenses. Copyright © 2017. Published by Elsevier Ltd.

  12. Frequency of deflagration in the in-tank precipitation process tanks due to loss of nitrogen purge system

    International Nuclear Information System (INIS)

    Jansen, J.M.; Mason, C.L.; Olsen, L.M.; Shapiro, B.J.; Gupta, M.K.; Britt, T.E.

    1994-01-01

    High-level liquid wastes (HLLW) from the processing of nuclear material at the Savannah River Site (SRS) are stored in large tanks in the F- and H-Area tank farms. The In-Tank Precipitation (ITP) process is one step in the processing and disposal of HLLW. The process hazards review for the ITP identified the need to implement provisions that minimize deflagration/explosion hazards associated with the process. The objective of this analysis is to determine the frequency of a deflagration in Tank 48 and/or 49 due to nitrogen purge system failures (including external events) and coincident ignition source. A fault tree of the nitrogen purge system coupled with ignition source probability is used to identify dominant system failures that contribute to the frequency of deflagration. These system failures are then used in the recovery analysis. Several human actions, recovery actions, and repair activities are identified that reduce total frequency. The actions are analyzed and quantified as part of a Human Reliability Analysis (HRA). The probabilities of failure of these actions are applied to the fault tree cutsets and the event trees

  13. Interaction of 3D dewetting nanodroplets on homogeneous and chemically heterogeneous substrates

    International Nuclear Information System (INIS)

    Asgari, M; Moosavi, A

    2014-01-01

    Long-time interaction of dewetting nanodroplets is investigated using a long-wave approximation method. Although three-dimensional (3D) droplets evolution dynamics exhibits qualitative behavior analogous to two-dimensional (2D) dynamics, there is an extensive quantitative difference between them. 3D dynamics is substantially faster than 2D dynamics. This can be related to the larger curvature and, as a consequence, the larger Laplace pressure difference between the droplets in 3D systems. The influence of various chemical heterogeneities on the behavior of droplets has also been studied. In the case of gradient surfaces, it is shown how the gradient direction could change the dynamics. For a chemical step located between the droplets, the dynamics is enhanced or weakened depending on the initial configuration of the system. (paper)

  14. Self-destruction and dewetting of thin polymer films the role of interfacial tensions

    CERN Document Server

    Reiter, G; Sharma, A

    2003-01-01

    We present real-time optical microscopy observations of the pattern evolution in self-destruction and subsequent dewetting of thin polymer films based on experiments with polydimethylsiloxane films sandwiched between silicon wafers and aqueous surfactant solutions. A clear scenario consisting of four distinct stages has been identified: amplification of surface fluctuations, break-up of the film and formation of holes, growth and coalescence of holes, and droplet formation and ripening. Besides a linear dependence on film viscosity and surface tension, the time tau for film rupture varied significantly with film thickness h (tau approx h sup 5), as expected from theory. While the role of long-range forces is dominant only in the first stage, the later stages are controlled by the combination of interfacial tensions resulting in the contact angle characterizing the three-phase contact line. During the first stage, the characteristic distance of the pattern remains constant, represented by a time-independent wa...

  15. Formation of controllable polymer micropatterns through liquid film electro-dewetting

    Science.gov (United States)

    Zhou, Shangru; Zheng, Huai; Li, Guoliang; Liu, Jie; Liu, Sheng

    2018-04-01

    Controllable polymer micropatterns, served as indispensable function structures, are extensively required in many micro/nano scientific areas and engineering applications. Exploring advanced methods of fabricating micropatterns is always a research hotspot. In this article, we introduce a novel method of patterning polymer by the electro-dewetting induced by corona discharge. For the first time, it is observed experimentally that liquid polymer on conductive/non-conductive patterned substrates, spontaneously converges from non-conductive areas to conductive areas under the action of ion wind. Taking advantage of such a flow phenomenon, controllable polymer micropatterns including microbump arrays and microwell arrays are fabricated successfully. Their sizes range from hundreds of microns to millimeters. Micropattern surfaces present an ultra-smooth characteristic, with roughness in the nanometer range.

  16. Influence of radioactive contamination to agricultural products due to dry and wet deposition processes during a nuclear emergency

    International Nuclear Information System (INIS)

    Hwang, Won Tae; Kim, Eun Han; Suh, Kyung Suk; Han, Moon Hee; Choi, Yong Ho; Lee, Chang Woo

    2002-01-01

    Combined with deposition model onto the ground of radionuclides, the influence of radioactive contamination to agricultural products was analyzed due to wet deposition as well as dry deposition from radioactive air concentration during a nuclear emergency. The previous dynamic food chain model, in which initial input parameter is only radionuclide concentrations on the ground, was improved for the evaluating of radioactive contamination to agricultural products from either radionuclide concentrations in air or radionuclide concentrations on the ground. As the results, in case of deposition onto the ground, wet deposition was more dominant process than dry deposition. While the contamination levels of agricultural products were dependent on the a variety of factors such as radionuclides and rainfall rate. It means that the contamination levels of agricultural products are determined from which is more dominant process between deposition on the ground and interception onto agricultural plants

  17. Analysis of the Processes in Spent Fuel Pools in Case of Loss of Heat Removal due to Water Leakage

    Directory of Open Access Journals (Sweden)

    Algirdas Kaliatka

    2013-01-01

    Full Text Available The safe storage of spent fuel assemblies in the spent fuel pools is very important. These facilities are not covered by leaktight containment; thus, the consequences of overheating and melting of fuel in the spent fuel pools can be very severe. On the other hand, due to low decay heat of fuel assemblies, the processes in pools are slow in comparison with processes in reactor core during LOCA accident. Thus, the accident management measures play a very important role in case of some accidents in spent fuel pools. This paper presents the analysis of possible consequences of fuel overheating due to leakage of water from spent fuel pool. Also, the accident mitigation measure, the late injection of water was evaluated. The analysis was performed for the Ignalina NPP Unit 2 spent fuel pool, using system thermal hydraulic code for severe accident analysis ATHLET-CD. The phenomena, taking place during such accident, are discussed. Also, benchmarking of results of the same accident calculation using ASTEC and RELAP/SCDAPSIM codes is presented here.

  18. U.S. Case Law and Legal Precedent Affirming the Due Process Rights of Immigrants Fleeing Persecution.

    Science.gov (United States)

    Sidhu, Shawn S; Boodoo, Ramnarine

    2017-09-01

    The political discourse on domestic immigration policy has shifted rapidly in recent years, mirrored by similar shifts in the geopolitical climate worldwide. However, a nuanced assessment of the legal basis backing such rhetoric is sorely lacking. This article examines the historical, legal, and case law precedent as it pertains specifically to immigrants who are fleeing persecution and residing within the United States. Due process rights emerged from the Fifth, Sixth, and Fourteenth Constitutional Amendments and have been expanded to include this population through several sequential United States Supreme Court Cases. We review the 1951 Convention Related to the Status of Refugees and 1967 Protocol Relating to the Status of Refugees and examine subsequent case law and legal precedent. We then present evidence documenting widespread violations of due process rights for immigrants fleeing persecution. Specifically, we address the right to a fair hearing for individuals fearing for their lives upon return to their home country, the right against wrongful detainment, and the right to apply for asylum regardless of religion or country of origin. We conclude by addressing potential counterarguments to our thesis, future directions, and the role of forensic psychiatrists. © 2017 American Academy of Psychiatry and the Law.

  19. A study of growth and thermal dewetting behavior of ultra-thin gold films using transmission electron microscopy

    Directory of Open Access Journals (Sweden)

    Sudheer

    2017-07-01

    Full Text Available The growth and solid-state dewetting behavior of Au thin films (0.7 to 8.4 nm deposited on the formvar film (substrate by sputtering technique have been studied using transmission electron microscopy. The size and number density of the Au nanoparticles (NPs change with an increase in the film thickness (0.7 to 2.8 nm. Nearly spherical Au NPs are obtained for 6 nm show capability to be used as an irreversible temperature sensor with a sensitivity of ∼0.1 CAF/°C. It is observed that annealing affects the crystallinity of the Au grains in the films. The electron diffraction measurement also shows annealing induced morphological evolution in the percolated Au thin films (≥3 nm during solid-state dewetting and recrystallization of the grains.

  20. A novel approach to fabricate dye-encapsulated polymeric micro- and nanoparticles by thin film dewetting technique.

    Science.gov (United States)

    Chatterjee, Manosree; Hens, Abhiram; Mahato, Kuldeep; Jaiswal, Namita; Mahato, Nivedita; Nagahanumaiah; Chanda, Nripen

    2017-11-15

    A new method is reported for fabrication of polymeric micro- and nanoparticles from an intermediate patterned surface originated by dewetting of a polymeric thin film. Poly (d, l-lactide-co-glycolide) or PLGA, a biocompatible polymer is used to develop a thin film over a clean glass substrate which dewets spontaneously in the micro-/nano-patterned surface of size range 50nm to 3.5µm. Since another water-soluble polymer, poly vinyl alcohol (PVA) is coated on the same glass substrate before PLGA thin film formation, developed micro-/nano-patterns are easily extracted in water in the form of micro- and nanoparticle mixture of size range 50nm to 3.0µm. This simplified method is also used to effectively encapsulate a dye molecule, rhodamine B inside the PLGA micro-/nanoparticles. The developed dye-encapsulated nanoparticles, PLGA-rhodamine are separated from the mixture and tested for in-vitro delivery application of external molecules inside human lung cancer cells. For the first time, the use of thin film dewetting technique is reported as a potential route for the synthesis of polymeric micro-/nanoparticles and effective encapsulation of external species therein. Copyright © 2017 Elsevier Inc. All rights reserved.

  1. Formation of precise 2D Au particle arrays via thermally induced dewetting on pre-patterned substrates

    Directory of Open Access Journals (Sweden)

    Dong Wang

    2011-06-01

    Full Text Available The fabrication of precise 2D Au nanoparticle arrays over a large area is presented. The technique was based on pre-patterning of the substrate before the deposition of a thin Au film, and the creation of periodic particle arrays by subsequent dewetting induced by annealing. Two types of pre-patterned substrates were used: The first comprised an array of pyramidal pits and the second an array of circular holes. For the dewetting of Au films on the pyramidal pit substrate, the structural curvature-driven diffusion cooperates with capillarity-driven diffusion, resulting in the formation of precise 2D particle arrays for films within a structure dependent thickness-window. For the dewetting of Au films on the circular hole substrate, the periodic discontinuities in the films, induced by the deposition, can limit the diffusion paths and lead to the formation of one particle per individual separated region (holes or mesas between holes, and thus, result in the evolution of precise 2D particle arrays. The influence of the pre-patterned structures and the film thickness is analyzed and discussed. For both types of pre-patterned substrate, the Au film thickness had to be adjusted in a certain thickness-window in order to achieve the precise 2D particle arrays.

  2. Formation of precise 2D Au particle arrays via thermally induced dewetting on pre-patterned substrates

    Science.gov (United States)

    Ji, Ran

    2011-01-01

    Summary The fabrication of precise 2D Au nanoparticle arrays over a large area is presented. The technique was based on pre-patterning of the substrate before the deposition of a thin Au film, and the creation of periodic particle arrays by subsequent dewetting induced by annealing. Two types of pre-patterned substrates were used: The first comprised an array of pyramidal pits and the second an array of circular holes. For the dewetting of Au films on the pyramidal pit substrate, the structural curvature-driven diffusion cooperates with capillarity-driven diffusion, resulting in the formation of precise 2D particle arrays for films within a structure dependent thickness-window. For the dewetting of Au films on the circular hole substrate, the periodic discontinuities in the films, induced by the deposition, can limit the diffusion paths and lead to the formation of one particle per individual separated region (holes or mesas between holes), and thus, result in the evolution of precise 2D particle arrays. The influence of the pre-patterned structures and the film thickness is analyzed and discussed. For both types of pre-patterned substrate, the Au film thickness had to be adjusted in a certain thickness-window in order to achieve the precise 2D particle arrays. PMID:21977445

  3. Study of test-mass charging process in the LISA missions due to diffuse γ-rays

    International Nuclear Information System (INIS)

    Finetti, N; Scrimaglio, R; Grimani, C; Fabi, M

    2009-01-01

    Gravitational inertial sensors will be placed on board the Laser Interferometer Space Antenna (LISA) and aboard its precursor mission LISA Pathfinder (LISA-PF) in order to detect low frequency gravitational waves in space. Free-floating test-masses (Au 7 Pt 3 cubes) will be housed in inertial sensors for detecting possible laser signal variations induced by gravitational waves. Charging of the LISA test-masses due to exposure of the spacecraft to cosmic radiation and energetic solar particles will affect operation of gravitational inertial sensors. In this paper we report on the role of diffuse γ-rays in charging the LISA and LISA-PF test-masses with respect to protons and helium nuclei. The diffuse γ-ray flux in the Galaxy has been interpolated taking into account the outcomes of recent calculations. A comparison with γ-ray observations gathered by different experiments (COMPTEL and EGRET, Milagro, Whipple, HEGRA, TIBET) has been carried out. Simulations of the test-mass charging process have been performed by means of the FLUKA2006.3b package. Monte Carlo simulations of the interaction of cosmic particles with the LISA spacecraft indicate that the diffuse γ-ray contribution to the average steady-state test-mass charging rate and to the single-sided power spectrum of the charge rate noise is marginal with respect to that due to galactic cosmic-rays.

  4. Length of proceedings as standard of due process of law in the practise of the Constitutional Court of Albania

    Directory of Open Access Journals (Sweden)

    Elsa Toska Dobjani

    2016-01-01

    Full Text Available ECHR, as an international treaty is part of the Albanian legal system. Among international law instruments, the ECHR enjoys a privileged status in the Albanian legal system by virtue of Article 17 paragraph 2 of the Constitution according to which restrictions to human rights and freedoms cannot infringe the substance of those rights and freedoms and in no case can exceed the restrictions provided for in the ECHR. Article 1 of the Convention requires States to secure the substance of the rights to those in their jurisdiction. The effect of Article 13 is thus to require the provision of a domestic remedy to deal with the substance of an arguable complaint under the Convention and to grant appropriate relief. The scope of this paper is to analyse the effectiveness of the complaint to the Constitutional Court with regard to length of proceedings as part of due process of law in terms of proceedings during the court trial and after the process has been finalized and the final decision should be executed.

  5. Process-oriented dose assessment model for 14C due to releases during normal operation of a nuclear power plant

    International Nuclear Information System (INIS)

    Aquilonius, Karin; Hallberg, Bengt

    2005-01-01

    Swedish nuclear utility companies are required to assess doses due to releases of radionuclides during normal operation. In 2001, calculation methods used earlier were updated due to new authority regulations. The isotope 14 C is of special interest in dose assessments due to the role of carbon in the metabolism of all life forms. Earlier, factors expressing the ratio between concentration of 14 C in air and in various plants were used. In order to extend the possibility to take local conditions into account, a process-oriented assessment model for uptake of carbon and doses from releases of 14 C to air was developed (POM 14 C). The model uses part of Daisy which has been developed to model the turnover of carbon in crops. [Hansen, S., Jensen, H.E., Nielsen, N.E., Svendsen, H., 1993. Description of the Soil Plant System Model DAISY, Basic Principles and Modelling Approach. Simulation Model for Transformation and Transport of Energy and Matter in the Soil Plant Atmosphere System. Jordbruksfoerlaget, The Royal Veterianary and Agricultural University, Copenhagen, Denmark]. The main objectives were to test model performance of the former method, and to investigate if taking site specific parameters into account to a greater degree would lead to major differences in the results. Several exposure pathways were considered: direct consumption of locally grown cereals, vegetables, and root vegetables, as well as consumption of milk and meat from cows having eaten fodder cereals and green fodder from the area around the nuclear plant. The total dose of the earlier model was compared with that of POM 14 C. The result of the former was shown to be slightly higher than the latter, but POM 14 C confirmed that the earlier results were of a reasonable magnitude. When full account of local conditions was taken, e.g. as regards solar radiation, temperature, and concentration of 14 C in air at various places in the surroundings of each nuclear plant, a difference in dose between

  6. Spiritual Occlusion and Systemic Integrity: Legal Evaluations of Due Process Protections and Freedom of Religious Expression and Practices Safeguards

    Directory of Open Access Journals (Sweden)

    Jason R. Jolicoeur

    2018-05-01

    Full Text Available As is the case with other constitutionally protected rights, the freedom of religion is not unlimited nor without restriction or constraint. Rather, the courts have long held that the state may have legitimate reasons for placing reasonable restrictions on the otherwise free exercise of religious practice. The courts have also held that the state cannot restrict religious practice in a capricious or gratuitous manner. However, the courts have also held that individuals have a constitutional right to due process legal protections. In many instances, these two freedoms exist independently of each other. In instances when they intersect, conflict may result from one right seeking hegemony over the other. In instances such as these, the courts may have to resolve conflicts by establishing legal principles and precedents regarding which of these constitutional protections will be granted contextual prominence over the other. Thus far, the legal evaluation of this important question has been confused at best and contradictory at worst. This has resulted in a number of substantive outcomes that pose significant challenges to the practice and application of both rights and an underlying avoidance of broader constitutional questions.

  7. Mn-doped Ge self-assembled quantum dots via dewetting of thin films

    Energy Technology Data Exchange (ETDEWEB)

    Aouassa, Mansour, E-mail: mansour.aouassa@yahoo.fr [LMON, Faculté des Sciences de Monastir, Avenue de l’environnement Monastir 5019 (Tunisia); Jadli, Imen [LMON, Faculté des Sciences de Monastir, Avenue de l’environnement Monastir 5019 (Tunisia); Bandyopadhyay, Anup [Department of Mechanical Engineering, Texas A& M University, College Station, TX 77843 (United States); Kim, Sung Kyu [Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Yuseong-daero 1689-gil, Yuseong-gu, Daejeon (Korea, Republic of); Department of Materials Science and Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon (Korea, Republic of); Karaman, Ibrahim [Department of Mechanical Engineering, Texas A& M University, College Station, TX 77843 (United States); Lee, Jeong Yong [Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS), Yuseong-daero 1689-gil, Yuseong-gu, Daejeon (Korea, Republic of); Department of Materials Science and Engineering, KAIST 291 Daehak-ro, Yuseong-gu, Daejeon (Korea, Republic of)

    2017-03-01

    Highlights: • We report the new fabrication approach for producing a self- assembled Mn dpoed Ge quantum dots (QDs) on SiO{sub 2} thin film with a Curie temperature above room temperature. These magnetic QDs are crystalline, monodisperse and have a well-defined shape and a controlled size. The investigation opens new routes for elaboration of self-assembled magnetic nanocrystals - Abstract: In this study, we demonstrate an original elaboration route for producing a Mn-doped Ge self-assembled quantum dots on SiO{sub 2} thin layer for MOS structure. These magnetic quantum dots are elaborated using dewetting phenomenon at solid state by Ultra-High Vacuum (UHV) annealing at high temperature of an amorphous Ge:Mn (Mn: 40%) nanolayer deposed at very low temperature by high-precision Solid Source Molecular Beam Epitaxy on SiO{sub 2} thin film. The size of quantum dots is controlled with nanometer scale precision by varying the nominal thickness of amorphous film initially deposed. The magnetic properties of the quantum-dots layer have been investigated by superconducting quantum interference device (SQUID) magnetometry. Atomic force microscopy (AFM), x-ray energy dispersive spectroscopy (XEDS) and transmission electron microscopy (TEM) were used to examine the nanostructure of these materials. Obtained results indicate that GeMn QDs are crystalline, monodisperse and exhibit a ferromagnetic behavior with a Curie temperature (TC) above room temperature. They could be integrated into spintronic technology.

  8. Designing Diameter-Modulated Heterostructure Nanowires of PbTe/Te by Controlled Dewetting.

    Science.gov (United States)

    Kumar, Abinash; Kundu, Subhajit; Samantaray, Debadarshini; Kundu, Paromita; Zanaga, Daniele; Bals, Sara; Ravishankar, N

    2017-12-13

    Heterostructures consisting of semiconductors with controlled morphology and interfaces find applications in many fields. A range of axial, radial, and diameter-modulated nanostructures have been synthesized primarily using vapor phase methods. Here, we present a simple wet chemical routine to synthesize heterostructures of PbTe/Te using Te nanowires as templates. A morphology evolution study for the formation of these heterostructures has been performed. On the basis of these control experiments, a pathway for the formation of these nanostructures is proposed. Reduction of a Pb precursor to Pb on Te nanowire templates followed by interdiffusion of Pb/Te leads to the formation of a thin shell of PbTe on the Te wires. Controlled dewetting of the thin shell leads to the formation of cube-shaped PbTe that is periodically arranged on the Te wires. Using control experiments, we show that different reactions parameters like rate of addition of the reducing agent, concentration of Pb precursor and thickness of initial Te nanowire play a critical role in controlling the spacing between the PbTe cubes on the Te wires. Using simple surface energy arguments, we propose a mechanism for the formation of the hybrid. The principles presented are general and can be exploited for the synthesis of other nanoscale heterostructures.

  9. Twin-assisted growth of nominally stable substrates underneath dewetted Au nanoparticles

    International Nuclear Information System (INIS)

    Liu, Fang; Xie, Dong Yue; Majdi, Tahereh; Zhu, Guo-zhen

    2016-01-01

    By applying a simple and inexpensive thermal treatment, we synthesized supported gold-oxide nanostructures, which have potential applications to plasmonic devices and biosensors. The regrowth of nominally stable substrates under gold nanoparticles is associated with the appearance of preferential orientations of dewetted nanoparticles and the formation of atomically sharp interfacial monolayers. Steps present at the interfacial monolayer usually occur at defects including the intersection points of twin planes at the interface. They were related to the nucleation and immigration of the interfacial monolayers, prompting the substrate regrowth. Accordingly, we proposed the twin-assisted growth mechanism, which provides insight on the synthesis of gold-oxide nanostructures. - Highlights: • The twin-assisted growth mechanism is proposed for the abnormal regrowth of substrate underneath Au nanoparticles. • The substrate regrowth is related to the steps and ledges that are present at the Au–MgAl_2O_4 interfacial monolayers. • Interfacial steps are detected at defects such as the intersecting points of twin planes at the interface.

  10. Twin-assisted growth of nominally stable substrates underneath dewetted Au nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Fang; Xie, Dong Yue [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240 (China); Majdi, Tahereh [Department of Engineering Physics, McMaster University, 1280 Main St. W., Hamilton, ON L8S 4L7 (Canada); Zhu, Guo-zhen, E-mail: zhugz@sjtu.edu.cn [State Key Laboratory of Metal Matrix Composites, School of Materials Science and Engineering, Shanghai Jiao Tong University, 800 Dongchuan Rd., Shanghai 200240 (China)

    2016-03-15

    By applying a simple and inexpensive thermal treatment, we synthesized supported gold-oxide nanostructures, which have potential applications to plasmonic devices and biosensors. The regrowth of nominally stable substrates under gold nanoparticles is associated with the appearance of preferential orientations of dewetted nanoparticles and the formation of atomically sharp interfacial monolayers. Steps present at the interfacial monolayer usually occur at defects including the intersection points of twin planes at the interface. They were related to the nucleation and immigration of the interfacial monolayers, prompting the substrate regrowth. Accordingly, we proposed the twin-assisted growth mechanism, which provides insight on the synthesis of gold-oxide nanostructures. - Highlights: • The twin-assisted growth mechanism is proposed for the abnormal regrowth of substrate underneath Au nanoparticles. • The substrate regrowth is related to the steps and ledges that are present at the Au–MgAl{sub 2}O{sub 4} interfacial monolayers. • Interfacial steps are detected at defects such as the intersecting points of twin planes at the interface.

  11. Changes to processes in estuaries and coastal waters due to intense multiple pressures - An introduction and synthesis

    Science.gov (United States)

    Mitchell, Steven B.; Jennerjahn, Tim C.; Vizzini, Salvatrice; Zhang, Weiguo

    2015-04-01

    From the 2013 ECSA conference 'Estuaries and Coastal Areas in Times of Intense Change' a theme emerged that has ended up being the focus of this Special Issue of Estuarine Coastal and Shelf Science, namely 'Changes to processes in estuaries and coastal waters due to intense multiple pressures'. Many parts of the world are continuing to experience unprecedented rates of economic growth, and those responsible for managing coastal and estuarine areas must respond accordingly. At the same time, global climate change and sea level rise are also continuing, placing new or more intense pressures on coastal areas that must be dealt with in ways that are as far as possible managed as a result of good scientific understanding. There are other pressures too, which depend on the system concerned. This article provides an overview of the papers contained within the Special Issue and provides a discussion of how these fit within the main theme of intense multiple stressors, considering how a balance can be achieved between the needs of various different stakeholders and interest groups, and the sustainability of the system concerned. We categorise the papers in four main groupings: (1) stressors related to sea level rise; (2) stressors related to changes in fresh water inputs; (3) stressors related to anthropogenic pollution; and (4) the use of indicators as a means of assessing the effects of stressors, and reflect on the fact that despite the diversity of different challenges and geographical regions involved many of the approaches and discussions contained within the Special Issue have strong similarities, leading to a set of overarching principles that should be considered when making recommendations on management strategies.

  12. Are the different gully morphologies due to different formation processes on the Kaiser dune field on Mars?

    Science.gov (United States)

    Pasquon, K.; Gargani, J.; Nachon, M.; Conway, S. J.; Massé, M.; Jouannic, G.; Balme, M. R.; Costard, F.; Vincendon, M.

    2017-12-01

    Diverse gully morphologies are seen on Mars and differences are often neglected for simplification. Here we describe in detail the morphology and present-day activity of two gully-systems on the Kaiser dune field in the southern hemisphere of Mars. We then compare their activity with that of the morphologically distinct linear dune gullies present on the same dunes. The studied gully-systems have large depositional aprons (named "large apron gullies") and occur on dune faces oriented westward. They are active from mid-autumn to late winter (i.e. from Ls 50° to Ls 180°) coinciding with CO2 ice condensation/sublimation cycles. Sandy material collapses from the alcove flanks onto the alcove floor sporadically throughout this period. This accumulated sand is remobilized by punctuated mass flows which we estimate to be up to 7100 m3 in volume. These flows run out on to the apron and occur between Ls 120° and Ls 160°. These mass flow events occur when the number of "digitate flows" is at its seasonal maximum. Digitate flows are characterized by long-narrow zig-zagging low-albedo tracks and do not seem to transport appreciable sediment, and they can number in the hundreds. Small pits appear at their termini or midway along and sometimes these pits are re-deepened by subsequent flows. These events repeat every year and using volume balance calculations we find that the whole system could be built on a timescale of hundreds of martian ears. These large apron gullies differ in morphology and timing from the linear dune gullies. The linear dune gullies are active in late winter, or beginning of spring when the CO2 frost finally sublimates, which occurs after the activity of the large apron gullies. Due to the difference of orientation between large apron gullies and linear dune as well as timing, we infer that insolation, which may influence (i) the depth to ground ice, (ii) the amount of volatiles deposits, is the main cause their differences. Sediment transport by CO2

  13. Water Dynamics and Dewetting Transitions in the Small Mechanosensitive Channel MscS

    Science.gov (United States)

    Anishkin, Andriy; Sukharev, Sergei

    2004-01-01

    The dynamics of confined water in capillaries and nanotubes suggests that gating of ion channels may involve not only changes of the pore geometry, but also transitions between water-filled and empty states in certain locations. The recently solved heptameric structure of the small mechanosensitive channel of Escherichia coli, MscS, has revealed a relatively wide (7–15 Å) yet highly hydrophobic transmembrane pore. Continuum estimations based on the properties of pore surface suggest low conductance and a thermodynamic possibility of dewetting. To test the predictions we performed molecular dynamics simulations of MscS filled with flexible TIP3P water. Irrespective to the initial conditions, several independent 6-ns simulations converged to the same stable state with the pore water-filled in the wider part, but predominantly empty in the narrow hydrophobic part, displaying intermittent vapor-liquid transitions. The polar gain-of-function substitution L109S in the constriction resulted in a stable hydration of the entire pore. Steered passages of Cl− ions through the narrow part of the pore consistently produced partial ion dehydration and required a force of 200–400 pN to overcome an estimated barrier of 10–20 kcal/mole, implying negligibly low conductance. We conclude that the crystal structure of MscS does not represent an open state. We infer that MscS gate, which is similar to that of the nicotinic ACh receptor, involves a vapor-lock mechanism where limited changes of geometry or surface polarity can locally switch the regime between water-filled (conducting) and empty (nonconducting) states. PMID:15111405

  14. How metal films de-wet substrates-identifying the kinetic pathways and energetic driving forces

    International Nuclear Information System (INIS)

    McCarty, Kevin F; Hamilton, John C; Thuermer, Konrad; Jones, Frank; Talin, A Alec; Bartelt, Norman C; Sato, Yu; K Schmid, Andreas; Saa, Angela; Figuera, Juan de la; Stumpf, Roland

    2009-01-01

    We study how single-crystal chromium films of uniform thickness on W(110) substrates are converted to arrays of three-dimensional (3D) Cr islands during annealing. We use low-energy electron microscopy (LEEM) to directly observe a kinetic pathway that produces trenches that expose the wetting layer. Adjacent film steps move simultaneously uphill and downhill relative to the staircase of atomic steps on the substrate. This step motion thickens the film regions where steps advance. Where film steps retract, the film thins, eventually exposing the stable wetting layer. Since our analysis shows that thick Cr films have a lattice constant close to bulk Cr, we propose that surface and interface stress provide a possible driving force for the observed morphological instability. Atomistic simulations and analytic elastic models show that surface and interface stress can cause a dependence of film energy on thickness that leads to an instability to simultaneous thinning and thickening. We observe that de-wetting is also initiated at bunches of substrate steps in two other systems, Ag/W(110) and Ag/Ru(0001). We additionally describe how Cr films are converted into patterns of unidirectional stripes as the trenches that expose the wetting layer lengthen along the W[001] direction. Finally, we observe how 3D Cr islands form directly during film growth at elevated temperature. The Cr mesas (wedges) form as Cr film steps advance down the staircase of substrate steps, another example of the critical role that substrate steps play in 3D island formation.

  15. Local processing enhancements associated with superior observational drawing are due to enhanced perceptual functioning, not weak central coherence.

    Science.gov (United States)

    Chamberlain, Rebecca; McManus, I C; Riley, Howard; Rankin, Qona; Brunswick, Nicola

    2013-01-01

    Individuals with drawing talent have previously been shown to exhibit enhanced local visual processing ability. The aim of the current study was to assess whether local processing biases associated with drawing ability result from a reduced ability to cohere local stimuli into global forms, or an increased ability to disregard global aspects of an image. Local and global visual processing ability was assessed in art students and controls using the Group Embedded Figures Task, Navon shape stimuli, the Block Design Task and the Autism Spectrum Quotient, whilst controlling for nonverbal IQ and artistic ability. Local processing biases associated with drawing appear to arise from an enhancement of local processing alongside successful filtering of global information, rather than a reduction in global processing. The relationship between local processing and drawing ability is independent of individual differences in nonverbal IQ and artistic ability. These findings have implications for bottom-up and attentional theories of observational drawing, as well as explanations of special skills in autism.

  16. Flows of a Vapor due to Phase Change Processes at the Condensed Phases with Temperature Fields as their Internal Structures

    National Research Council Canada - National Science Library

    Onishi, Yoshimoto; Ooshida, Takeshi

    2005-01-01

    Transient to steady motions of a vapor caused by the evaporation and condensation processes occurring at the condensed phases placed in parallel have been studied based on the Boltzmann equation of BGK type...

  17. Solid-state dewetting of Au-Ni bi-layer films mediated through individual layer thickness and stacking sequence

    Science.gov (United States)

    Herz, Andreas; Theska, Felix; Rossberg, Diana; Kups, Thomas; Wang, Dong; Schaaf, Peter

    2018-06-01

    In the present work, the solid-state dewetting of Au-Ni bi-layer thin films deposited on SiO2/Si is systematically studied with respect to individual layer thickness and stacking sequence. For this purpose, a rapid heat treatment at medium temperatures is applied in order to examine void formation at the early stages of the dewetting. Compositional variations are realized by changing the thickness ratio of the bi-layer films, while the total thickness is maintained at 20 nm throughout the study. In the event of Au/Ni films annealed at 500 °C, crystal voids exposing the substrate are missing regardless of chemical composition. In reverse order, the number of voids per unit area in two-phase Au-Ni thin films is found to be governed by the amount of Au-rich material. At higher temperatures up to 650 °C, a decreased probability of nucleation comes at the expense of a major portion of cavities, resulting in the formation of bubbles in 15 nm Ni/5 nm Au bi-layers. Film buckling predominantly occurred at phase boundaries crossing the bubbles.

  18. Effect of annealing ambient on anisotropic retraction of film edges during solid-state dewetting of thin single crystal films

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gye Hyun; Thompson, Carl V., E-mail: cthomp@mit.edu [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 01239 (United States); Ma, Wen [Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 01239 (United States); Yildiz, Bilge [Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 01239 (United States); Department of Nuclear Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 01239 (United States)

    2016-08-21

    During solid-state dewetting of thin single crystal films, film edges retract at a rate that is strongly dependent on their crystallographic orientations. Edges with kinetically stable in-plane orientations remain straight as they retract, while those with other in-plane orientations develop in-plane facets as they retract. Kinetically stable edges have retraction rates that are lower than edges with other orientations and thus determine the shape of the natural holes that form during solid-state dewetting. In this paper, measurements of the retraction rates of kinetically stable edges for single crystal (110) and (100) Ni films on MgO are presented. Relative retraction rates of kinetically stable edges with different crystallographic orientations are observed to change under different annealing conditions, and this accordingly changes the initial shapes of growing holes. The surfaces of (110) and (100) films were also characterized using low energy electron diffraction, and different surface reconstructions were observed under different ambient conditions. The observed surface structures were found to correlate with the observed changes in the relative retraction rates of the kinetically stable edges.

  19. Attorney General forces Infectious Diseases Society of America to redo Lyme guidelines due to flawed development process.

    Science.gov (United States)

    Johnson, L; Stricker, R B

    2009-05-01

    Lyme disease is one of the most controversial illnesses in the history of medicine. In 2006 the Connecticut Attorney General launched an antitrust investigation into the Lyme guidelines development process of the Infectious Diseases Society of America (IDSA). In a recent settlement with IDSA, the Attorney General noted important commercial conflicts of interest and suppression of scientific evidence that had tainted the guidelines process. This paper explores two broad ethical themes that influenced the IDSA investigation. The first is the growing problem of conflicts of interest among guidelines developers, and the second is the increasing centralisation of medical decisions by insurance companies, which use treatment guidelines as a means of controlling the practices of individual doctors and denying treatment for patients. The implications of the first-ever antitrust investigation of medical guidelines and the proposed model to remediate the tainted IDSA guidelines process are also discussed.

  20. Phase-matched light amplification by three-wave mixing process in a birefringent fiber due to externally applied stress

    International Nuclear Information System (INIS)

    Ohashi, M.; Kitayama, K.; Ishida, Y.; Uchida, N.

    1982-01-01

    A novel method to achieve phase-matched light amplification in a birefringent fiber via the three-wave mixing is proposed by using frequency shift change due to the stress applied to the fiber. It is confirmed that the signal power from a cw laser diode at lambda = 1.292 μm is amplified by 6.1 x 10 3 times in the birefringent fiber pumped with a Q-switched Nd: yttrium aluminum garnet laser at lambda = 1.064 μm. This will provide a new fiber-optic light signal amplifier having a good tolerance for variation of signal wavelengths

  1. Probabilistic analysis and fatigue damage assessment of offshore mooring system due to non-Gaussian bimodal tension processes

    Science.gov (United States)

    Chang, Anteng; Li, Huajun; Wang, Shuqing; Du, Junfeng

    2017-08-01

    Both wave-frequency (WF) and low-frequency (LF) components of mooring tension are in principle non-Gaussian due to nonlinearities in the dynamic system. This paper conducts a comprehensive investigation of applicable probability density functions (PDFs) of mooring tension amplitudes used to assess mooring-line fatigue damage via the spectral method. Short-term statistical characteristics of mooring-line tension responses are firstly investigated, in which the discrepancy arising from Gaussian approximation is revealed by comparing kurtosis and skewness coefficients. Several distribution functions based on present analytical spectral methods are selected to express the statistical distribution of the mooring-line tension amplitudes. Results indicate that the Gamma-type distribution and a linear combination of Dirlik and Tovo-Benasciutti formulas are suitable for separate WF and LF mooring tension components. A novel parametric method based on nonlinear transformations and stochastic optimization is then proposed to increase the effectiveness of mooring-line fatigue assessment due to non-Gaussian bimodal tension responses. Using time domain simulation as a benchmark, its accuracy is further validated using a numerical case study of a moored semi-submersible platform.

  2. Altered joint tribology in osteoarthritis: Reduced lubricin synthesis due to the inflammatory process. New horizons for therapeutic approaches.

    Science.gov (United States)

    Szychlinska, M A; Leonardi, R; Al-Qahtani, M; Mobasheri, A; Musumeci, G

    2016-06-01

    Osteoarthritis (OA) is the most common form of joint disease. This review aimed to consolidate the current evidence that implicates the inflammatory process in the attenuation of synovial lubrication and joint tissue homeostasis in OA. Moreover, with these findings, we propose some evidence for novel therapeutic strategies for preventing and/or treating this complex disorder. The studies reviewed support that inflammatory mediators participate in the onset and progression of OA after joint injury. The flow of pro-inflammatory cytokines following an acute injury seems to be directly associated with altered lubricating ability in the joint tissue. The latter is associated with reduced level of lubricin, one of the major joint lubricants. Future research should focus on the development of new therapies that attenuate the inflammatory process and restore lubricin synthesis and function. This approach could support joint tribology and synovial lubrication leading to improved joint function and pain relief. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  3. A case of mental nerve paresthesia due to dynamic compression of alveolar inferior nerve along an elongated styloid process.

    Science.gov (United States)

    Gooris, Peter J J; Zijlmans, Jan C M; Bergsma, J Eelco; Mensink, Gertjan

    2014-07-01

    Spontaneous paresthesia of the mental nerve is considered an ominous clinical sign. Mental nerve paresthesia has also been referred to as numb chin syndrome. Several potentially different factors have been investigated for their role in interfering with the inferior alveolar nerve (IAN) and causing mental nerve neuropathy. In the present case, the patient had an elongated calcified styloid process that we hypothesized had caused IAN irritation during mandibular movement. This eventually resulted in progressive loss of sensation in the mental nerve region. To our knowledge, this dynamic irritation, with complete recovery after resection of the styloid process, has not been previously reported. Copyright © 2014 American Association of Oral and Maxillofacial Surgeons. Published by Elsevier Inc. All rights reserved.

  4. The changes of astaxanthin content and chemical characteristics of tiger prawn (Penaeus monodon) due to processing: boiling, smoking and frying

    Science.gov (United States)

    Swastawati, F.

    2018-03-01

    Food processing using high temperatures can cause changes in pigment color and chemical characteristics in food stuffs, including prawn. The aim of this research was to evaluate the changes in pigment and chemical characteristics of tiger prawn caused by boiling, smoking and frying. Ten kg of tiger prawn was boiled, smoked and fried at the temperature of ± 100 °C for ± 10 min. The results showed that boiling, smoking and frying gave a significant effect (P < 0.05) on the astaxanthin pigment, pH, moisture, protein, salt content, Aw and color. The content of astaxanthin pigments in fresh prawn, boiled prawn, smoked prawn and fried prawn was: 132.79 ± 1.5 μg·g-1 82.89 ± 0.92 μg·g-1 78.28 ± 0.1 μg·g-1 and 91.35 ± 2.59 μg·g-1, respectively. The value of °Hue on fresh prawn, boiled prawn, smoked prawn and fried prawn was: 87.85° 52.5° 55.94° and 53.98°. The tiger prawn processed by the smoking method has preferable by panelist rather than processed by boiling and frying.

  5. Enhancement of the neutral-beam stopping cross section in fusion plasmas due to multistep collision processes

    International Nuclear Information System (INIS)

    Boley, C.D.; Janev, R.K.; Post, D.E.

    1983-10-01

    Multistep processes involving excited atomic states are found to produce a substantial increase in the stopping cross section for a neutral hydrogen beam injected into a plasma, and thus to reduce the beam penetration. For typical plasma and beam parameters of current large tokamak experiments, the stopping cross-sectional enhancement is found to vary from 25% to 50% depending on the beam energy, plasma density, and impurity level. For neutral hydrogen beams with energies greater than or equal to 500 keV, envisioned in tokamak amd mirror reactor designs, the enhancement can be as large as 80 to 90%

  6. Modelling of nitric acid production in the Advanced Cold Process Canister due to irradiation of moist air

    International Nuclear Information System (INIS)

    Henshaw, J.

    1994-01-01

    This report summarises the work performed for SKB of Sweden on the modelling of nitric acid production in the gaseous environment of the Advanced Cold Process Canister (ACPC). The model solves the simultaneous chemical rate equations describing the radiation chemistry of He/Ar/N 2 /O 2 /H 2 O gas mixture, involving over 200 chemical reactions. The amount of nitric acid produced as a function of time for typical ACPC conditions has been calculated using the model and the results reported. 11 refs, 11 figs, 1 tab

  7. Numerical simulation of the bubble growth due to hydrogen isotopes inventory processes in plasma-irradiated tungsten

    International Nuclear Information System (INIS)

    Sang, Chaofeng; Sun, Jizhong; Bonnin, Xavier; Liu, Shengguang; Wang, Dezhen

    2013-01-01

    Hydrogen isotopes (HI) inventory is a key issue for fusion devices like ITER. It is especially urgent to understand how HI are retained in tungsten since it currently is the most important candidate material for the plasma-facing wall. Bubble growth is an important experimental complication that yet prevents a full understanding of HI retention processes in tungsten walls and most critically the divertor elements. In this work, we develop a model based on rate equations, which includes the bubble growth in tungsten being exposed to a HI plasma. In the model, HI molecules can be produced through recombination processes on the inner surface of a bubble, and HI molecules can also dissociate themselves to solute atoms, and the latter diffuse into the bulk wall because of very high pressures inside the bubble. The present model is applied to simulate how HI are retained in plasma-irradiated tungsten in the form of molecules to explain the wall temperature, trap concentration, incident HI flux and fluence dependencies of bubble growth

  8. Calcification in the staghorn coral Acropora acuminata: variations in apparent skeletal incorporation of radioisotopes due to different methods of processing

    International Nuclear Information System (INIS)

    Crossland, C.J.; Barnes, D.J.

    1977-01-01

    Pieces of branch from the staghorn coral Acropora acuminata were incubated with 45 CaCl 2 and NaH 14 CO 3 under identical conditions in the light or in the dark. Specimens were then processed in different ways. All specimens were placed in N KOH to digest tissues. Some were placed in KOH immediately after incubation; others were placed in KOH after 2 h washing, or after 2 h extraction with methanol-chloroform-water. Specimens were washed in running fresh water or running seawater; some were killed in liquid N 2 before washing. Radioactivity associated with skeleton and tissues was determined. The method of processing profoundly affected the results. In dark incubations, there was up to a four-fold difference in apparent skeletal incorporation of 45 Ca ++ between average values obtained for the different treatments. For 14 C incorporation, there was a difference of up to 2.5 times. In light incubations, skeletal incorporation of both radioisotopes showed a two-fold difference between high and low average values obtained for the different treatments. (orig.) [de

  9. Can a new behaviorally oriented training process to improve lifting technique prevent occupationally related back injuries due to lifting?

    Science.gov (United States)

    Lavender, Steven A; Lorenz, Eric P; Andersson, Gunnar B J

    2007-02-15

    A prospective randomized control trial. To determine the degree to which a new behavior-based lift training program (LiftTrainer; Ascension Technology, Burlington, VT) could reduce the incidence of low back disorder in distribution center jobs that require repetitive lifting. Most studies show programs aimed at training lifting techniques to be ineffective in preventing low back disorders, which may be due to their conceptual rather than behavioral learning approach. A total of 2144 employees in 19 distribution centers were randomized into either the LiftTrainer program or a video control group. In the LiftTrainer program, participants were individually trained in up to 5, 30-minute sessions while instrumented with motion capture sensors to quantify the L5/S1 moments. Twelve months following the initial training, injury data were obtained from company records. Survival analyses (Kaplan-Meier) indicated that there was no difference in injury rates between the 2 training groups. Likewise, there was no difference in the turnover rates. However, those with a low (<30 Nm) average twisting moment at the end of the first session experienced a significantly (P < 0.005) lower rate of low back disorder than controls. While overall the LiftTrainer program was not effective, those with twisting moments below 30 Nm reported fewer injuries, suggesting a shift in focus for "safe" lifting programs.

  10. Supervisors’ experiences with the return-to-work process of hospital workers absent from work due to a health problem

    DEFF Research Database (Denmark)

    Stochkendahl, Mette Jensen; Myburgh, Corrie; Hartvigsen, Jan

    context. Aim: In order to gain knowledge about the potential role of supervisors in supporting RTW of a sick listed worker in Denmark, an exploratory qualitative pilot study will be conducted. We seek to open a window of understanding into the experience of managers who have been involved in RTW...... procedures, including the managers’ roles and contributions to the process. Methods: Using purposive sampling, approximately 20 hospital supervisors in charge of conducting sick leave interviews will participate in a face‐to‐face or focus group interviews in order to identify barriers and facilitators...... comparison analysis approach and computer assisted qualitative data analysis. Results: The study is in progress. Results will be available at the time of the conference. Conclusion: We will address questions regarding which factors supervisors feel are important to them in supporting returning workers...

  11. Analysis of residual stresses due to roll-expansion process: Finite element computation and validation by experimental tests

    International Nuclear Information System (INIS)

    Aufaure, M.; Boudot, R.; Zacharie, G.; Proix, J.M.

    1987-01-01

    The steam generator heat exchangers of pressurized water reactors are made of U-shaped tubes, both ends of them being fixed to a plate by roll-expansion. This process consists in increasing the tube section by means of a rotating tool in order to apply its outer side to the surface of the hole through the plate. As reported by de Keroulas (1986), in service cracks appeared on these tubes in the transition from expanded to nonexpanded portions. So we developed a program to compute residual stresses at the surface of the tubes, which caused their cracking, and to endeavour to lower their level by acting on some parameters. This program was validated by experimental tests. (orig.)

  12. Effectiveness of manual therapy versus surgery in pain processing due to carpal tunnel syndrome: A randomized clinical trial.

    Science.gov (United States)

    Fernández-de-Las-Peñas, C; Cleland, J; Palacios-Ceña, M; Fuensalida-Novo, S; Alonso-Blanco, C; Pareja, J A; Alburquerque-Sendín, F

    2017-08-01

    People with carpal tunnel syndrome (CTS) exhibit widespread pressure pain and thermal pain hypersensitivity as a manifestation of central sensitization. The aim of our study was to compare the effectiveness of manual therapy versus surgery for improving pain and nociceptive gain processing in people with CTS. The trial was conducted at a local regional Hospital in Madrid, Spain from August 2014 to February 2015. In this randomized parallel-group, blinded, clinical trial, 100 women with CTS were randomly allocated to either manual therapy (n = 50), who received three sessions (once/week) of manual therapies including desensitization manoeuvres of the central nervous system, or surgical intervention (n = 50) group. Outcomes including pressure pain thresholds (PPT), thermal pain thresholds (HPT or CPT), and pain intensity which were assessed at baseline, and 3, 6, 9 and 12 months after the intervention by an assessor unaware of group assignment. Analysis was by intention to treat with mixed ANCOVAs adjusted for baseline scores. At 12 months, 95 women completed the follow-up. Patients receiving manual therapy exhibited higher increases in PPT over the carpal tunnel at 3, 6 and 9 months (all, p < 0.01) and higher decrease of pain intensity at 3 month follow-up (p < 0.001) than those receiving surgery. No significant differences were observed between groups for the remaining outcomes. Manual therapy and surgery have similar effects on decreasing widespread pressure pain sensitivity and pain intensity in women with CTS. Neither manual therapy nor surgery resulted in changes in thermal pain sensitivity. The current study found that manual therapy and surgery exhibited similar effects on decreasing widespread pressure pain sensitivity and pain intensity in women with carpal tunnel syndrome at medium- and long-term follow-ups investigating changes in nociceptive gain processing after treatment in carpal tunnel syndrome. © 2017 European Pain Federation - EFIC®.

  13. Constitutional Law--Procedural Due Process--Student Has Right to Have Attorney Present at University Disciplinary Hearing When Criminal Charges Are Pending.

    Science.gov (United States)

    Vessels, Rodney Jay

    1978-01-01

    In the case of Gabrilowitz v Newman the court used the due process balancing test to conclude that a student has a right to have counsel present at a university disciplinary hearing where the conduct in question is the object of a pending criminal proceeding. Available from J. Reuben Clark Law School, Brigham Young U., Provo, UT 84602. (MSE)

  14. The Substantive and Procedural Due Process Rights of Students Accused of Criminal Behavior in School and the Educational Rights of Adjudicated Youths.

    Science.gov (United States)

    Brown, Frank

    This paper--part of a collection of 54 papers from the 48th annual conference of the Education Law Association held in November 2002-- addresses juvenile justice. Its central issue is how to protect children of color in elementary and secondary schools with constitutional due process where attendance is compulsory and, at the same time, maintain a…

  15. Changes in guava (Psidium guajava L. var. Paluma nectar volatile compounds concentration due to thermal processing and storage

    Directory of Open Access Journals (Sweden)

    Maria Ivaneide Coutinho Correa

    2010-12-01

    Full Text Available Guava nectars were formulated for approximately 10, 12, or 14 ºBrix, with 40% guava pulp. Sodium benzoate, 500 mg.kg-1 was used as preservative. The Brix value was adjusted with saturated sucrose syrup. The guava nectar was pasteurized (85 ºC/42 seconds in tubular heat exchanger and then hot filled in 500 mL white glass bottles. The products were stored either at room temperature (25 ± 5 ºC or refrigerated (5 ± 2 ºC under fluorescent light exposure and analyzed on the day after processing (time zero and also 40, 80, and 120 days of storage. Eight compounds were identified and quantified by Gas Chromatography (GC -Mass Spectrometry (MS: hexanal, (E-hex-2-enal, 1-hexenol, (Z-hex-3-enol, (Z-hex-3-enyl acetate, phenyl-3-propyl acetate, cinnamyl acetate, and acetic acid. There was no significant effect of thermal treatment on the volatile compound concentrations, except for a significant decrease (p = 0.0001 in hexanal and (Z-hex-3-enyl acetate (p = 0.0029. As for the storage time, there was a much greater decrease in the esters contents, such as (Z-hex-3-enyl and phenyl-3-propyl acetates. Cinnamyl acetate had the greatest decrease over storage time. Refrigeration was better than room temperature for guava nectar volatile compounds stability over storage time, mainly for esters compounds, which are important for the product aroma and flavor

  16. Losses of neutral injected fast ions due to adiabaticity breaking processes in a field-reversed configuration

    International Nuclear Information System (INIS)

    Takahashi, Toshiki; Inoue, Koji; Ishizuka, Takashi; Kondoh, Yoshiomi; Iwasawa, Naotaka

    2004-02-01

    Losses of neutral beam (NB) injected fast ions from the confinement region of a Field-Reversed Configuration (FRC) with a strong magnetic mirror are numerically analyzed for parameters relevant to NB injection experiments on the FIX (FRC injection experiment) device [T. Asai et al., Phys. Plasmas 7, 2294 (2000)]. Ionization processes of beam particles are calculated by the Monte Carlo method. The confinement of beam ions is discussed with the concept of accessible regions that restrict the ion excursion and are determined from two constants of motion, the kinetic energy and canonical angular momentum, in the case of an axisymmetric and a steady state FRC without an electrostatic field. From the calculation of the accessible regions, it is found that all the fast ions suffer from the orbit loss on the wall surface and/or the end loss. Single particle orbits are also calculated to find a difference of confinement properties from the results by employing the accessible regions. The magnetic moment is observed to show non-adiabatic motions of the beam ions, which cause a gradual orbit loss on the wall even in a case that a strong magnetic mirror is applied. The results show that the correlation of the magnetic moment disappears as the fast ions experience the density gradient around the separatrix surface and the field-null points. (author)

  17. Alterations in soil microbial activity and N-transformation processes due to sulfadiazine loads in pig-manure

    International Nuclear Information System (INIS)

    Kotzerke, Anja; Sharma, Shilpi; Schauss, Kristina; Heuer, Holger; Thiele-Bruhn, Soeren; Smalla, Kornelia; Wilke, Berndt-Michael; Schloter, Michael

    2008-01-01

    Most veterinary drugs enter the environment via manure application. However, it is unclear how these substances interact with soil biota. Therefore, it was the aim of the present study to investigate the effects of manure containing different concentrations of the antibiotic sulfadiazine (SDZ) on the soil microbial communities. It was shown that manure alone has a stimulating effect on microbial activity. Only potential nitrification was negatively influenced by manure application. The addition of SDZ to the manure reduced microbial activity. Depending on the SDZ concentration, levels of activity were in the range of the control soil without manure application. Also, selected processes in nitrogen turnover were negatively influenced by the addition of SDZ to the manure, with nitrification being the only exception. The effects were visible for up to 4 days after application of the manure with or without SDZ and were correlated with the bioavailability of the antibiotic. - This study gives first insights into the effects of manure containing the antibiotic sulfadiazine on microbial activity and nitrogen transformation potentials in soil

  18. Medial temporal lobe-dependent repetition suppression and enhancement due to implicit versus explicit processing of individual repeated search displays

    Directory of Open Access Journals (Sweden)

    Thomas eGeyer

    2012-10-01

    Full Text Available Using visual search, functional magnetic resonance imaging (fMRI and patient studies have demonstrated that medial temporal lobe (MTL structures differentiate repeated from novel displays – even when observers are unaware of display repetitions. This suggests a role for MTL in both explicit and, importantly, implicit learning of repeated sensory information (Greene et al., 2007. However, recent behavioral studies suggest, by examining visual search and recognition performance concurrently, that observers have explicit knowledge of at least some of the repeated displays (Geyer et al., 2010. The aim of the present fMRI study was thus to contribute new evidence regarding the contribution of MTL structures to explicit versus implicit learning in visual search. It was found that MTL activation was increased for explicit and, respectively, decreased for implicit relative to baseline displays. These activation differences were most pronounced in left anterior parahippocampal cortex, especially when observers were highly trained on the repeated displays. The data are taken to suggest that explicit and implicit memory processes are linked within MTL structures, but expressed via functionally separable mechanisms (repetition enhancement vs. -suppression. They further show that repetition effects in visual search would have to be investigated at the display level.

  19. Pollution Status of Trace Metals in Groundwater Due to Industrail Activities in and Around Dhaka Export Processing Zone, Bangladesh

    Directory of Open Access Journals (Sweden)

    GOLAM AHMED

    2012-06-01

    Full Text Available Effluents from multiindustrail activities influence inland water system directly, which subsiquently affect groundwater quality and human health. Some previous reports indicated that inadequate treatment process of discharged effluent of Dhaka Export Processing Zone (DEPZ increased the concentrations of pollutants in surface water system and deteriorated total fishing and agricultural system around DEPZ and its connected area. Therefore, the present study was conducted to investigate wether the concentration of selective metals viz. Li, V, Cr, Co, Ni, Cu, Zn, Ga, As, Se, Rb, Sr, Ag, Cd, Cs, Ba, Pb and U in two types of groundwater sources were either with in the permissible guidlines or influenced by DEPZ multi industrail on their levels of contamination. The concentrations of metals were determined using inductively Couples Plasma Mass Spectrometry (ICP-MS. The mean concentrations of the elements in both types of groundwater were in the levels of their permissible guidlines, except for Ni (12.91 µg/L, Ga (0.48µg/L, Sr (90.26 µg/L and Cs (0.07µg//Lin groundwater inside DEPZ, which were 1.30, 5.00, 1.50 and 1.40 times higher than the maximum permissible limit (MPL of 10 µg/L, 0.09 µg/L, 60 µg/L, and 0.05µg/L, respectively. The mean concentrations of Li (6.85 µg/L, Zn(268 µg/L, Ga (0.12 µg/L, Sr (131 µg/L and Cs (0.07 µg/L were 3.43, 1.34, 1.33, 2.18, 1.40 times higher then the MPL of 2 µg/L, 200 µg/L, 0.09 µg/L, 60 µg/L and 0.05 µg/L, respectively, in groundwater around DEPZ. Comparatively Zn and Sr possessed higher concentrations, and Cs and U possessed lower concentration in both types of groundwater sources. The elements were distributed in homogeneous and hetrogeneous manner among the source points for deep-tubewell (DTWS and shallow tubewell (STWs, respectively. The significant positive correlations were found between the elements viz., Co-V (0.85, Ni-Sr ((0.70, Co-Cd (0.86, As-Se (0.99, Cs-Zn (0.95, Li-U (0.,71, Zn-U (0

  20. Low-level laser therapy (LLLT) accelerates the sternomastoid muscle regeneration process after myonecrosis due to bupivacaine.

    Science.gov (United States)

    Alessi Pissulin, Cristiane Neves; Henrique Fernandes, Ana Angélica; Sanchez Orellana, Alejandro Manuel; Rossi E Silva, Renata Calciolari; Michelin Matheus, Selma Maria

    2017-03-01

    Because of its long-lasting analgesic action, bupivacaine is an anesthetic used for peripheral nerve block and relief of postoperative pain. Muscle degeneration and neurotoxicity are its main limitations. There is strong evidence that low-level laser therapy (LLLT) assists in muscle and nerve repair. The authors evaluated the effects of a Gallium Arsenide laser (GaAs), on the regeneration of muscle fibers of the sternomastoid muscle and accessory nerve after injection of bupivacaine. In total, 30 Wistar adult rats were divided into 2 groups: control group (C: n=15) and laser group (L: n=15). The groups were subdivided by antimere, with 0.5% bupivacaine injected on the right and 0.9% sodium chloride on the left. LLLT (GaAs 904nm, 0,05W, 2.8J per point) was administered for 5 consecutive days, starting 24h after injection of the solutions. Seven days after the trial period, blood samples were collected for determination of creatine kinase (CK). The sternomastoid nerve was removed for morphological and morphometric analyses; the surface portion of the sternomastoid muscle was used for histopathological and ultrastructural analyses. Muscle CK and TNFα protein levels were measured. The anesthetic promoted myonecrosis and increased muscle CK without neurotoxic effects. The LLLT reduced myonecrosis, characterized by a decrease in muscle CK levels, inflammation, necrosis, and atrophy, as well as the number of central nuclei in the muscle fibers and the percentage of collagen. TNFα values remained constant. LLLT, at the dose used, reduced fibrosis and myonecrosis in the sternomastoid muscle triggered by bupivacaine, accelerating the muscle regeneration process. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Due diligence

    International Nuclear Information System (INIS)

    Sanghera, G.S.

    1999-01-01

    The Occupational Health and Safety (OHS) Act requires that every employer shall ensure the health and safety of workers in the workplace. Issues regarding the practices at workplaces and how they should reflect the standards of due diligence were discussed. Due diligence was described as being the need for employers to identify hazards in the workplace and to take active steps to prevent workers from potentially dangerous incidents. The paper discussed various aspects of due diligence including policy, training, procedures, measurement and enforcement. The consequences of contravening the OHS Act were also described

  2. Preventing dewetting during rapid-thermal annealing of FePt films with enhanced L1{sub 0} ordering by introducing Ag cap-layers

    Energy Technology Data Exchange (ETDEWEB)

    Hsiao, S.N., E-mail: pmami.hsiao@gmail.com [Department of Materials Science and Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Wu, S.C. [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 40227, Taiwan (China); Liu, S.H. [Department of Materials Science and Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Tsai, J.L., E-mail: tsaijl@dragon.nchu.edu.tw [Department of Materials Science and Engineering, National Chung Hsing University, Taichung 40227, Taiwan (China); Chen, S.K. [Department of Materials Science and Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Chang, Y.C. [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Lee, H.Y. [Scientific Research Division, National Synchrotron Radiation Research Center, Hsinchu 30077, Taiwan (China)

    2015-11-15

    High-order FePt continuous films with a strong (001) texture were fabricated on a glass substrate by introducing Ag layers and rapid thermal annealing (RTA). The dewetting of the (001)-textured FePt was suppressed during RTA with high heating rates (>80 K/s). The Ag cap layers not only increased the in-plane tensile stress, but also improved the (001) anisotropy and L1{sub 0} ordering of the FePt layers. All continuous Ag/FePt bilayer films possessed strong perpendicular anisotropies and high-ordered states irrespective of the Ag layer thickness. - Highlights: • Dewetting of (001) FePt fims were suppressed by introducing Ag cap layers. • Ag layers enhanced in-plane tensile stress, (001) texture and L1{sub 0} ordering. • Irrespective of Ag thickness, the Ag/FePt films exhibited strong (001) texture.

  3. Preventing dewetting during rapid-thermal annealing of FePt films with enhanced L10 ordering by introducing Ag cap-layers

    International Nuclear Information System (INIS)

    Hsiao, S.N.; Wu, S.C.; Liu, S.H.; Tsai, J.L.; Chen, S.K.; Chang, Y.C.; Lee, H.Y.

    2015-01-01

    High-order FePt continuous films with a strong (001) texture were fabricated on a glass substrate by introducing Ag layers and rapid thermal annealing (RTA). The dewetting of the (001)-textured FePt was suppressed during RTA with high heating rates (>80 K/s). The Ag cap layers not only increased the in-plane tensile stress, but also improved the (001) anisotropy and L1 0 ordering of the FePt layers. All continuous Ag/FePt bilayer films possessed strong perpendicular anisotropies and high-ordered states irrespective of the Ag layer thickness. - Highlights: • Dewetting of (001) FePt fims were suppressed by introducing Ag cap layers. • Ag layers enhanced in-plane tensile stress, (001) texture and L1 0 ordering. • Irrespective of Ag thickness, the Ag/FePt films exhibited strong (001) texture

  4. Fabrication of ordered arrays of micro- and nanoscale features with control over their shape and size via templated solid-state dewetting.

    Science.gov (United States)

    Ye, Jongpil

    2015-05-08

    Templated solid-state dewetting of single-crystal films has been shown to be used to produce regular patterns of various shapes. However, the materials for which this patterning method is applicable, and the size range of the patterns produced are still limited. Here, it is shown that ordered arrays of micro- and nanoscale features can be produced with control over their shape and size via solid-state dewetting of patches patterned from single-crystal palladium and nickel films of different thicknesses and orientations. The shape and size characteristics of the patterns are found to be widely controllable with varying the shape, width, thickness, and orientation of the initial patches. The morphological evolution of the patches is also dependent on the film material, with different dewetting behaviors observed in palladium and nickel films. The mechanisms underlying the pattern formation are explained in terms of the influence on Rayleigh-like instability of the patch geometry and the surface energy anisotropy of the film material. This mechanistic understanding of pattern formation can be used to design patches for the precise fabrication of micro- and nanoscale structures with the desired shapes and feature sizes.

  5. Law n. 13.015/2014: Amendment of Labor Magazine Feature and Possible offenses to Constitutional Principles of Due Process Legal Access to Jurisdiction and Effectiveness

    Directory of Open Access Journals (Sweden)

    Sérgio Henriques Zandona Freitas

    2015-12-01

    Full Text Available This scientific article aims to study the reforms undertaken by the Law 13.015/2014 under the proposed amendments to the labor resources of magazines, and a growing demand in the edition of overviews by the Regionals Labors Court. At first, the theoretical basis, we analyze the prospects of the constitutional process model within the framework leveraged as a democratic state. After, it enters to the principle concept of due process of law, the access Jurisdiction and Effectiveness, doing, in a third moment, a brief survey and survey as the main proposals of changes made by Law n. 13.015/2014, demonstrating the likelihood that some provisions of this standard or not contradict principles and constitutional guarantees. Trough the deductive method and the bibliographic research this article has been written from a large conception to a small one. And as technical proceeding were used the theme analysis as a way of looking for a solution for the problem.

  6. Online interferometric study of viscoelastic rupture and necking deformation of as-spun (iPP) fibres due to creep process.

    Science.gov (United States)

    Sokkar, Taha; El-Farahaty, Kermal; Azzam, Amira

    2015-01-01

    Creep deformation under constant load leads to rupture when the polymer chains can no longer separate and accommodate the load. This fracture phenomenon is investigated interferometrically. The creep behaviour of as-spun isotactic Polypropylene (iPP) fibres is studied at different stresses, different initial lengths and different radii. The creep rate, which defines the velocity of the creep deformation and the dimensional stability of the material, is studied. The failure time and stress of iPP due to creep process is determined. The necking deformation was in situ detected during creep process. The mean refractive indices (n(P) andn⊥) profiles of iPP fibres were determined at different positions along the fibre axis before and after necking. The relation between the creep behaviour and different optical and structural parameters is investigated. Microinterferograms are given for illustration. © 2015 The Authors Journal of Microscopy © 2015 Royal Microscopical Society.

  7. Brand-name drug, generic drug, orphan drug. Pharmacological therapy with biosimilar drugs – provision of due diligence in the treatment process

    Science.gov (United States)

    Zajdel, Justyna

    2013-01-01

    Due diligence in the process of provision of healthcare services refers, among other elements, to the application of pharmacological therapy at a time which offers the greatest chance for a successful outcome of treatment, i.e. for achieving the optimum expected effect understood as an improvement in the patient's health, reduction of health risks or elimination of the disease. However, due diligence may also refer to actions aimed at ensuring that neither the patient nor the healthcare payer is required to incur unreasonable costs in the process of treatment. The validity of that statement stems not only from normative acts but also from ethical standards laid down in the Medical Code of Ethics (Article 57 section 2). It often happens that the provision of optimal treatment calls for deviations from the formal provisions included in Summary Product Characteristics (SPCs), and the application of drugs that are bioequivalent to reference drugs, which translates into a significant reduction of costs. The present study addresses the problem of acceptability of a specific form of drug substitution consisting in the replacement of a reference drug with a generic drug. Also explored are legal aspects associated with the possibility of therapy based on “off-label use”. The study reviews normative acts existing in the Polish and EU legislation. It also provides a clear definition of orphan drug, which has made it possible to make a distinction and investigate mutual relations between the concepts of brand-name (reference) drug, orphan drug and generic drug. PMID:24592133

  8. Brand-name drug, generic drug, orphan drug. Pharmacological therapy with biosimilar drugs - provision of due diligence in the treatment process.

    Science.gov (United States)

    Zajdel, Justyna; Zajdel, Radosław

    2013-01-01

    Due diligence in the process of provision of healthcare services refers, among other elements, to the application of pharmacological therapy at a time which offers the greatest chance for a successful outcome of treatment, i.e. for achieving the optimum expected effect understood as an improvement in the patient's health, reduction of health risks or elimination of the disease. However, due diligence may also refer to actions aimed at ensuring that neither the patient nor the healthcare payer is required to incur unreasonable costs in the process of treatment. The validity of that statement stems not only from normative acts but also from ethical standards laid down in the Medical Code of Ethics (Article 57 section 2). It often happens that the provision of optimal treatment calls for deviations from the formal provisions included in Summary Product Characteristics (SPCs), and the application of drugs that are bioequivalent to reference drugs, which translates into a significant reduction of costs. The present study addresses the problem of acceptability of a specific form of drug substitution consisting in the replacement of a reference drug with a generic drug. Also explored are legal aspects associated with the possibility of therapy based on "off-label use". The study reviews normative acts existing in the Polish and EU legislation. It also provides a clear definition of orphan drug, which has made it possible to make a distinction and investigate mutual relations between the concepts of brand-name (reference) drug, orphan drug and generic drug.

  9. Ensuring due process in the IACUC and animal welfare setting: considerations in developing noncompliance policies and procedures for institutional animal care and use committees and institutional officials.

    Science.gov (United States)

    Hansen, Barbara C; Gografe, Sylvia; Pritt, Stacy; Jen, Kai-Lin Catherine; McWhirter, Camille A; Barman, Susan M; Comuzzie, Anthony; Greene, Molly; McNulty, Justin A; Michele, Daniel Eugene; Moaddab, Naz; Nelson, Randall J; Norris, Karen; Uray, Karen D; Banks, Ron; Westlund, Karin N; Yates, Bill J; Silverman, Jerald; Hansen, Kenneth D; Redman, Barbara

    2017-10-01

    Every institution that is involved in research with animals is expected to have in place policies and procedures for the management of allegations of noncompliance with the Animal Welfare Act and the U.S. Public Health Service Policy on the Humane Care and Use of Laboratory Animals. We present here a model set of recommendations for institutional animal care and use committees and institutional officials to ensure appropriate consideration of allegations of noncompliance with federal Animal Welfare Act regulations that carry a significant risk or specific threat to animal welfare. This guidance has 3 overarching aims: 1 ) protecting the welfare of research animals; 2 ) according fair treatment and due process to an individual accused of noncompliance; and 3 ) ensuring compliance with federal regulations. Through this guidance, the present work seeks to advance the cause of scientific integrity, animal welfare, and the public trust while recognizing and supporting the critical importance of animal research for the betterment of the health of both humans and animals.-Hansen, B. C., Gografe, S., Pritt, S., Jen, K.-L. C., McWhirter, C. A., Barman, S. M., Comuzzie, A., Greene, M., McNulty, J. A., Michele, D. E., Moaddab, N., Nelson, R. J., Norris, K., Uray, K. D., Banks, R., Westlund, K. N., Yates, B. J., Silverman, J., Hansen, K. D., Redman, B. Ensuring due process in the IACUC and animal welfare setting: considerations in developing noncompliance policies and procedures for institutional animal care and use committees and institutional officials. © FASEB.

  10. Meghan Rene, et al., v. Dr. Suellen Reed, et al. "Due Process." Lesson Plans for Secondary School Teachers on the Constitutional Requirement of "Due Process of Law." Courts in the Classroom: Curriculum Concepts and Other Information on Indiana's Courts for the K-12 Educator.

    Science.gov (United States)

    Osborn, Elizabeth

    In the Rene v. Reed case, Meghan Rene and other disabled students argued that their due process rights were violated in regard to the Indiana Statewide Testing for Educational Progress (ISTEP) graduation examination. This set of four lesson plans uses the case of Rene v. Reed, which was first argued before the Indiana Supreme Court, to study the…

  11. Variation Process of Radiation Belt Electron Fluxes due to Interaction With Chorus and EMIC Rising-tone Emissions Localized in Longitude

    Science.gov (United States)

    Kubota, Y.; Omura, Y.

    2017-12-01

    Using results of test particle simulations of a large number of electrons interacting with a pair of chorus emissions, we create Green's functions to model the electron distribution function after all of the possible interactions with the waves [Omura et al., 2015]. Assuming that the waves are generated in a localized range of longitudes in the dawn side, we repeat taking the convolution integral of the Green's function with the distribution function of the electrons injected into the generation region of the localized waves. From numerical and theoretical analyses, we find that electron acceleration process only takes place efficiently below 4 MeV. Because extremely relativistic electrons go through the wave generation region rapidly due to grad-B0 and curvature drift, they don't have enough interaction time to be accelerated. In setting up the electrons after all interaction with chorus emissions as initial electron distribution function, we also compute the loss process of radiation belt electron fluxes due to interaction with EMIC rising-tone emissions generated in a localized range of longitudes in the dusk side [Kubota and Omura,2017]. References: (1) Omura, Y., Y. Miyashita, M. Yoshikawa, D. Summers, M. Hikishima, Y. Ebihara, and Y. Kubota (2015), Formation process of relativistic electron flux through interaction with chorus emissions in the Earth's inner magnetosphere, J. Geophys. Res. Space Physics, 120, 9545-9562, doi:10.1002/2015JA021563. (2) Kubota, Y., and Y. Omura (2017), Rapid precipitation of radiation belt electrons induced by EMIC rising tone emissions localized in longitude inside and outside the plasmapause, J. Geophys. Res. Space Physics, 122, 293-309, doi:10.1002/2016JA023267.

  12. Due diligence

    OpenAIRE

    Rohanová, Tereza

    2015-01-01

    One of the main strategic goals of an owner is the growth of their company. To seek company growth in todays ever changing world, company owners and their management frequently turn to the discipline of mergers and acquisitions (hereinafter M&A). This M&A focus is evidenced by the sustained long term growth of the M&A markets, which for example in the Czech Republic alone amounted to a 38% increase between the years 2015 and 2016. The transaction decision making process takes place with an in...

  13. Integrated batch production and maintenance scheduling for multiple items processed on a deteriorating machine to minimize total production and maintenance costs with due date constraint

    Directory of Open Access Journals (Sweden)

    Zahedi Zahedi

    2016-04-01

    Full Text Available This paper discusses an integrated model of batch production and maintenance scheduling on a deteriorating machine producing multiple items to be delivered at a common due date. The model describes the trade-off between total inventory cost and maintenance cost as the increase of production run length. The production run length is a time bucket between two consecutive preventive maintenance activities. The objective function of the model is to minimize total cost consisting of in process and completed part inventory costs, setup cost, preventive and corrective maintenance costs and rework cost. The problem is to determine the optimal production run length and to schedule the batches obtained from determining the production run length in order to minimize total cost.

  14. Broadband generation by multiple four-wave mixing process due to ASE Q-switching in high-power double-clad ytterbium-doped fiber amplifier

    Science.gov (United States)

    Chowdhury, Sourav D.; Shekhar, Nishant; Saha, Maitreyee; Sen, Ranjan; Pal, Mrinmay

    2014-11-01

    Broadband output from 1060nm to 1700nm and cascaded four-wave mixing generated red light pulsing is observed in a fiber amplifier set up consisting of a 5.5m double clad, double D shaped Ytterbium doped fiber, a single clad passive fiber for excess pump absorption and a splitter, both with and without a CW seed. Self-pulsing occurs from ASE due to passive Q-switching by saturable absorption effect of the active fiber and also depends on splice loss. The pulses generate broadband output by multiple four-wave mixing process with maximum broadening efficiency near 1300nm which is the zero dispersion wavelength for silica fiber. Pulses traveling both in forward and backward direction have enough peak power and energy to damage splice points and fiber components. When seeded the self-pulsing and broadband generation is often suppressed but again generate at increased pump powers.

  15. Assessment of structural integrity of Monju steel liner against sodium leakage and combustion. Modeling of thinning process of liner due to corrosion in structural analysis

    International Nuclear Information System (INIS)

    Tsukimori, K.; Kato, T.; Furuhashi, I.; Iwata, K.; Akatsu, M.

    2001-01-01

    The lining structure of LMFBR (Liquid Metal cooled Fast Breeder Reactor) has an important role to prohibit leaking sodium from touching a concrete floor in a sodium leakage incident. JNC (Japan Nuclear Cycle Development Institute) experienced a sodium leakage incident in 1995 in the secondary heat transport system room of the prototype LMFBR MONJU. In this incident, a part of the liner was covered with a certain amount of high temperature leaked sodium and its compounds. Visible but small distortion and thinning of the liner were detected, which were due to heating by sodium fire and chemical corrosion, respectively. To simulate the MONJU incident, JNC conducted a series of sodium leakage tests, in one of which severer corrosion (molten salt type corrosion) than that in the MONJU incident was observed. In order to secure the conservativeness in the integrity assessment of the liner, consideration of a severest corrosion process was demanded. This means that the loss of parts of the structure with time should be considered in the structural analyses. In this study a modeling of thinning process of the liner was developed in order to realize reasonable analysis from the point of view of actual phenomena. The concept of the method is to release the stress of the lost region by using artificial creep and reducing Young's modulus. The necessity of this kind of model and the validity was verified through an application analysis of the liner in the secondary heat transport system room of MONJU. (authors)

  16. Characteristics of the gait adaptation process due to split-belt treadmill walking under a wide range of right-left speed ratios in humans.

    Science.gov (United States)

    Yokoyama, Hikaru; Sato, Koji; Ogawa, Tetsuya; Yamamoto, Shin-Ichiro; Nakazawa, Kimitaka; Kawashima, Noritaka

    2018-01-01

    The adaptability of human bipedal locomotion has been studied using split-belt treadmill walking. Most of previous studies utilized experimental protocol under remarkably different split ratios (e.g. 1:2, 1:3, or 1:4). While, there is limited research with regard to adaptive process under the small speed ratios. It is important to know the nature of adaptive process under ratio smaller than 1:2, because systematic evaluation of the gait adaptation under small to moderate split ratios would enable us to examine relative contribution of two forms of adaptation (reactive feedback and predictive feedforward control) on gait adaptation. We therefore examined a gait behavior due to on split-belt treadmill adaptation under five belt speed difference conditions (from 1:1.2 to 1:2). Gait parameters related to reactive control (stance time) showed quick adjustments immediately after imposing the split-belt walking in all five speed ratios. Meanwhile, parameters related to predictive control (step length and anterior force) showed a clear pattern of adaptation and subsequent aftereffects except for the 1:1.2 adaptation. Additionally, the 1:1.2 ratio was distinguished from other ratios by cluster analysis based on the relationship between the size of adaptation and the aftereffect. Our findings indicate that the reactive feedback control was involved in all the speed ratios tested and that the extent of reaction was proportionally dependent on the speed ratio of the split-belt. On the contrary, predictive feedforward control was necessary when the ratio of the split-belt was greater. These results enable us to consider how a given split-belt training condition would affect the relative contribution of the two strategies on gait adaptation, which must be considered when developing rehabilitation interventions for stroke patients.

  17. Nuclide Release Behavior from a Repository for a Pyro-process HLW and SF due to Variation of the MWCF Properties

    International Nuclear Information System (INIS)

    Lee, Youn Myoung; Hwang, Yong Soo

    2009-01-01

    An assessment program for an optional evaluation of a repository both for disposal of such high-level wastes (HLWs) from various steps of pyro-processes of PWR spent nuclear fuel (SF) and for direct disposal of PWR and CANDU SFs has been developed by utilizing general purpose GoldSim developing tool, by which nuclide transports in the near- and far-field of a repository as well as a transport through a biosphere under various natural and manmade disruptive events affecting a nuclide release could be modeled and evaluated. KAERI has been in charge of modeling and developing assessment tools by which the above mentioned repository system could be assessed in accordance with various features, events, and processes (FEPs) that could happen in and around the repository system. To cope with such various natural and manmade disruptive FEPs as well as normal release scenarios, all the possible cases in view of the Korean circumstances should be modeled and have been evaluated even though we have not yet have any repository. A possible case, among many others, with the variation of such physical properties as the fracture width and the rock matrix diffusion depth, associated with the natural fractures in the geological rock media, along which nuclide could be transported preferentially with the flow of groundwater is considered in the current study. Due to whatever the reason, such as e,g., the earthquake or human intrusion, it is assumed that the physical properties of the major water conducting fault (MWCF) is changed resulting in the size of fracture width and the matrix diffusion depth. For such case another illustration is made for probabilistic evaluation of a hypothetical Korean HLW repository, as similarly done in the previous studies

  18. Fabrication of core-shell nanostructures via silicon on insulator dewetting and germanium condensation: towards a strain tuning method for SiGe-based heterostructures in a three-dimensional geometry.

    Science.gov (United States)

    Naffouti, Meher; David, Thomas; Benkouider, Abdelmalek; Favre, Luc; Cabie, Martiane; Ronda, Antoine; Berbezier, Isabelle; Abbarchi, Marco

    2016-07-29

    We report on a novel method for the implementation of core-shell SiGe-based nanocrystals combining silicon on insulator dewetting in a molecular beam epitaxy reactor with an ex situ Ge condensation process. With an in situ two-step process (annealing and Ge deposition) we produce two families of islands on the same sample: Si-rich, formed during the first step and, all around them, Ge-rich formed after Ge deposition. By increasing the amount of Ge deposited on the annealed samples from 0 to 18 monolayers, the islands' shape in the Si-rich zones can be tuned from elongated and flat to more symmetric and with a larger vertical aspect ratio. At the same time, the spatial extension of the Ge-rich zones is progressively increased as well as the Ge content in the islands. Further processing by ex situ rapid thermal oxidation results in the formation of a core-shell composition profile in both Si and Ge-rich zones with atomically sharp heterointerfaces. The Ge condensation induces a Ge enrichment of the islands' shell of up to 50% while keeping a pure Si core in the Si-rich zones and a ∼25% SiGe alloy in the Ge-rich ones. The large lattice mismatch between core and shell, the absence of dislocations and the islands' monocrystalline nature render this novel class of nanostructures a promising device platform for strain-based band-gap engineering. Finally, this method can be used for the implementation of ultralarge scale meta-surfaces with dielectric Mie resonators for light manipulation at the nanoscale.

  19. Observation of interior and boundary-layer mixing processes due to near-inertial waves in a stratified basin without tides

    Science.gov (United States)

    van der Lee, Eefke; Umlauf, Lars

    2010-05-01

    Near-inertial waves form an important contribution to oceanic energy and shear spectra, and thus play a major role in mixing the ocean's interior. Here, we compare internal-wave mixing processes in the interior of a stratified basin to those occurring on the sloping boundaries. We use the virtually tideless Baltic Sea as a natural laboratory, allowing us to isolate the effect of near-inertial waves that is otherwise (often) overshadowed by internal tides. The measurements presented here consist of moored ADCPs and CTD loggers in the center of the basin and on the slopes, combined with densely spaced shear-microstructure and ADCP cross-slope transects. During summer stratification, a three-layer density structure, with a thermocline and a deeper halocline, was observed with clear signals of downward near-inertial energy propagation after a short wind event. These motions are interpreted as near-inertial wave modes interacting with the sloping topography. Dissipation rates observed in the center of the basin scale with shear and stratification parameters in the way suggested by MacKinnon and Gregg (2003) for the shelf. On the slopes, microstructure transects reveal a periodic near-bed dissipation rate signal and a growing and decaying bottom boundary layer (BBL) thickness; both signals are triggered by near-bottom currents oscillating with a near-inertial frequency. Near-bottom dissipation rates are greatly enhanced compared to the interior, and, due to the straining of lateral density gradients by the cross-slope velocity, mixing is rather efficient, and contributes significantly to the basin-scale mixing.

  20. Effect of Feed Composition Changing at Naphtha Catalytic Reforming Unit Due to Involvement of Gasoline Fraction Obtained by Diesel Fuels Hydrodewaxing into the Processing

    OpenAIRE

    Belinskaya, Natalia Sergeevna; Ivanchina, Emilia Dmitrievna; Ivashkina, Elena Nikolaevna; Frantsina, Evgeniya Vladimirovna; Silko, Galina Yurievna

    2014-01-01

    One of the primary products of hydrodewaxing process is stable gasoline, which is characterized by low octane number on the one hand. On the other hand, it contains a significant amount of iso-paraffins (on average 45% wt.) and naphthenes (on average 25% wt.), which are reagents in the naphtha catalytic reforming process primary reactions. Feasibility of stable gasoline obtained by means of diesel fuel catalytic hydrodewaxing process involving into the processing at the naphtha catalytic refo...

  1. Characterization of Ag nanostructures fabricated by laser-induced dewetting of thin films

    Energy Technology Data Exchange (ETDEWEB)

    Nikov, Ru.G., E-mail: rumen_nikov24@abv.bg [Institute of Electronics, Bulgarian Academy of Sciences, Tzarigradsko Chaussee 72, Sofia 1784 (Bulgaria); Nedyalkov, N.N.; Atanasov, P.A. [Institute of Electronics, Bulgarian Academy of Sciences, Tzarigradsko Chaussee 72, Sofia 1784 (Bulgaria); Hirsch, D.; Rauschenbach, B. [Leibniz Institute of Surface Modification (IOM), 15 Permoserstrasse, D-04318 Leipzig (Germany); Grochowska, K.; Sliwinski, G. [Centre for Plasma and Laser Engineering, The Szewalski Institute, Polish Academy of Sciences, 14 Fiszera St., 80-231 Gdansk (Poland)

    2016-06-30

    Highlights: • Laser processing of Ag films produces nanoparticles with narrow size distribution. • The parameters of the nanoparticle array depend on the environment at annealing. • Raman analysis indicates that the fabricated structures can be used in SERS. - Abstract: The paper presents results on laser nanostructuring of Ag thin films. The thin films are deposited on glass substrates by pulsed laser deposition technology. The as fabricated films are then annealed by nanosecond laser pulses delivered by Nd:YAG laser system operated at λ = 355 nm. The film modification is studied as a function of the film thickness and the parameters of the laser irradiation as pulse number and laser fluence. In order to estimate the influence of the environment on the characteristics of the fabricated structures the Ag films are annealed in different surrounding media: water, air and vacuum. It is found that at certain conditions the laser treatment may lead to decomposition of the films into a monolayer of nanoparticles with narrow size distribution. The optical properties of the fabricated nanostructures are investigated on the basis of transmission spectra taken by optical spectrometer. In the measured spectra plasmon resonance band is observed as its shape and position vary depending on the processing conditions. The fabricated structures are covered with Rhodamine 6G and tested as active substrates for Surface Enhanced Raman Spectroscopy (SERS).

  2. Fabrication of Au-Pd Core-shell Nanoparticles using Au Thin-Film Dewetting at High Temperature and Chemical Synthesis Methods

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Min-Gyu; Lee, Hye-Jung; Oh, Yong-Jun [Hanbat National Univ., Daejeon (Korea, Republic of)

    2016-07-15

    Au-Pd bimetallic nanoparticles (NPs) have received a lot of attention in the fields of catalysts and hydrogen sensors. In this study, Au-Pd core-shell NP arrays were successfully fabricated using two steps: formation of the ordered array of Au NPs cores via solid-state dewetting of a Au thin film on a topographic silica substrate, and Pd shell formation via chemical synthesis using two different surfactants (CTAB and CTAC). Using the CTAB surfactant in particular, a 2-D composite structure comprised of an ordered array of Au-Pd NPs, with smaller Pd NPs on the nanoscopic gaps between the Au-Pd NPs, could be formed. This structure is expected to have potential application in resistance-base hydrogen sensors.

  3. Photonic metasurface made of array of lens-like SiGe Mie resonators formed on (100) Si substrate via dewetting

    Science.gov (United States)

    Poborchii, Vladimir; Shklyaev, Alexander; Bolotov, Leonid; Uchida, Noriyuki; Tada, Tetsuya; Utegulov, Zhandos N.

    2017-12-01

    Metasurfaces consisting of arrays of high-index Mie resonators concentrating/redirecting light are important for integrated optics, photodetectors, and solar cells. Herein, we report the optical properties of low-Ge-content SiGe lens-like Mie resonator island arrays fabricated via dewetting during Ge deposition on a Si(100) surface at approximately 900 °C. We observe enhancement of the Si interaction with light owing to the efficient island-induced light concentration in the submicron-depth Si layer, which is mediated by both near-field Mie resonance leaking into the substrate and far-field light focusing. Such metasurfaces can improve the Si photodetector and solar-cell performance.

  4. Hepatic processing determines dual activity of alpha-tocopheryl succinate: a novel paradigm for a shift in biological activity due to provitamin-to-vitamin conversion

    Czech Academy of Sciences Publication Activity Database

    Neužil, Jiří; Massa, H.

    2005-01-01

    Roč. 327, č. 4 (2005), s. 1024-1027 ISSN 0006-291X Institutional research plan: CEZ:AV0Z5052915; CEZ:AV0Z50520514 Keywords : vitamin E * alpha-tocopheryl succinate * hepatic processing Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.000, year: 2005

  5. Improved performance of solution-processed a-InGaZnO thin-film transistors due to Ar/O{sub 2} mixed-plasma treatment

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kwan-Soo; Hwang, Yeong-Hyeon; Hwang, In-Chan; Cho, Won-Ju [Kwangwoon University, Seoul (Korea, Republic of)

    2014-08-15

    We investigated the effects of Ar and O{sub 2} treatment and of Ar/O{sub 2} mixed plasma treatment on the electrical characteristics of solution-processed amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs). The electrical performance and the instability of a-IGZO TFTs were significantly improved by the plasma treatments. The plasma treatments reduced the carbon-based residual contamination that acted as possible trap sites. In particular, the O{sub 2}-plasma treatment produced a significant improvement in the reliability of a-IGZO TFTs when compared with the Ar-plasma-treated device, owing to the elimination of residual carbon in the active channel of the solution-processed a-IGZO. However, the optimized improvement of the solution-processed a-IGZO TFT under a gate bias stress was obtained for the device treated with an Ar/O{sub 2} mixed-gas plasma. The plasma treatment in the Ar/O{sub 2}-mixed ambience remarkably enhanced not only the reliability but also the electrical performance of the a-IGZO TFT; the on/off-current ratio, the field-effect mobility, and the subthreshold slope were 6.78 x 10{sup 7}, 1.24 cm{sup 2}/V·s, and 513 mV/dec, respectively.

  6. Improved performance of solution-processed a-InGaZnO thin-film transistors due to Ar/O2 mixed-plasma treatment

    International Nuclear Information System (INIS)

    Kim, Kwan-Soo; Hwang, Yeong-Hyeon; Hwang, In-Chan; Cho, Won-Ju

    2014-01-01

    We investigated the effects of Ar and O 2 treatment and of Ar/O 2 mixed plasma treatment on the electrical characteristics of solution-processed amorphous indium-gallium-zinc-oxide (a-IGZO) thin-film transistors (TFTs). The electrical performance and the instability of a-IGZO TFTs were significantly improved by the plasma treatments. The plasma treatments reduced the carbon-based residual contamination that acted as possible trap sites. In particular, the O 2 -plasma treatment produced a significant improvement in the reliability of a-IGZO TFTs when compared with the Ar-plasma-treated device, owing to the elimination of residual carbon in the active channel of the solution-processed a-IGZO. However, the optimized improvement of the solution-processed a-IGZO TFT under a gate bias stress was obtained for the device treated with an Ar/O 2 mixed-gas plasma. The plasma treatment in the Ar/O 2 -mixed ambience remarkably enhanced not only the reliability but also the electrical performance of the a-IGZO TFT; the on/off-current ratio, the field-effect mobility, and the subthreshold slope were 6.78 x 10 7 , 1.24 cm 2 /V·s, and 513 mV/dec, respectively.

  7. Disruption of TLR3 signaling due to cleavage of TRIF by the hepatitis A virus protease-polymerase processing intermediate, 3CD.

    Directory of Open Access Journals (Sweden)

    Lin Qu

    2011-09-01

    Full Text Available Toll-like receptor 3 (TLR3 and cytosolic RIG-I-like helicases (RIG-I and MDA5 sense viral RNAs and activate innate immune signaling pathways that induce expression of interferon (IFN through specific adaptor proteins, TIR domain-containing adaptor inducing interferon-β (TRIF, and mitochondrial antiviral signaling protein (MAVS, respectively. Previously, we demonstrated that hepatitis A virus (HAV, a unique hepatotropic human picornavirus, disrupts RIG-I/MDA5 signaling by targeting MAVS for cleavage by 3ABC, a precursor of the sole HAV protease, 3C(pro, that is derived by auto-processing of the P3 (3ABCD segment of the viral polyprotein. Here, we show that HAV also disrupts TLR3 signaling, inhibiting poly(I:C-stimulated dimerization of IFN regulatory factor 3 (IRF-3, IRF-3 translocation to the nucleus, and IFN-β promoter activation, by targeting TRIF for degradation by a distinct 3ABCD processing intermediate, the 3CD protease-polymerase precursor. TRIF is proteolytically cleaved by 3CD, but not by the mature 3C(pro protease or the 3ABC precursor that degrades MAVS. 3CD-mediated degradation of TRIF depends on both the cysteine protease activity of 3C(pro and downstream 3D(pol sequence, but not 3D(pol polymerase activity. Cleavage occurs at two non-canonical 3C(pro recognition sequences in TRIF, and involves a hierarchical process in which primary cleavage at Gln-554 is a prerequisite for scission at Gln-190. The results of mutational studies indicate that 3D(pol sequence modulates the substrate specificity of the upstream 3C(pro protease when fused to it in cis in 3CD, allowing 3CD to target cleavage sites not normally recognized by 3C(pro. HAV thus disrupts both RIG-I/MDA5 and TLR3 signaling pathways through cleavage of essential adaptor proteins by two distinct protease precursors derived from the common 3ABCD polyprotein processing intermediate.

  8. Diversity of arbuscular mycorrhizal fungi in a chrono-sequence of alluvial and degraded soils due to mining processes in bajo cauca antioqueno, Colombia

    International Nuclear Information System (INIS)

    Medina S, Marisol; Orozco P, Francisco H; Marquez F, Maria E

    2009-01-01

    Arbuscular mycorrhizal fungi (AMF) presence and diversity were evaluated in undisturbed and disturbed soils form alluvial mining processes. The soils belong to the Tropic Fluvaquent, Typical Dystropept, and Typical Paleudult sub-groups which corresponded to Low, Middle and High terraces, respectively, of the Cauca river at Taraza town. AMF propagules were multiplied in Leonard jars under glass house conditions using sterile substrate, modified Hoagland's solution and different fractions of soil used as sources of inoculum, which corresponded to the size of the spores. A first assay was made in maize (Zea mays) which allowed mycorrhizal colonization in roots but not spore production. In a second assay, in kudzu (Pueraria phaseoloides) AMF spores and colonized roots were obtained with the treatments corresponding to propagules obtained from high terrace and disturbed soil. These treatments presented a significant effect on kudzu yield (P?0,001) respect to the other treatments. The AMF spores of undisturbed and disturbed soils showed low infective capacity. Nevertheless, propagules of AMF were multiplied in trap cultures, which produced spores of four morpho types. One of these was identified as G. microagregatum. The polymorphism obtained by RAPD's made possible the differentiation of these morpho types with the primer OPA2. Similitude above 38% was achieved using UPGMA system. The results indicated that four morpho types belong to the genus Glomus, but they possibly belong to different species. Our results are promissory in the differentiation of native strains of AMF with low number of spores collected from soil samples in rehabilitation processes, which normally is unknown.

  9. Logistics for evaluation of doses received by IOE due to handling 18FDG-radiopharmaceutical during processing (IEN/CNEN) and in radiodiagnostic (clinical)

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Osvaldir P. dos; Silva, Joao Carlos P.; Silva, Luiz Carlos Reina P.; Cortines, Geraldo, E-mail: osvaldir@ien.gov.br, E-mail: jcarlos@ien.gov.br, E-mail: reina@ien.gov.br, E-mail: gcortines@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil)

    2013-07-01

    The objective of this study is to propose an improvement in radiological practices involving production, transportation and application of radiopharmaceutical {sup 18}F, by tracking the radiation doses received by occupationally exposed individuals (OEI) that develop production practices, transportation and application of some patients in hospitals and clinics in Rio de Janeiro, the radiopharmaceutical {sup 18}FDG. In light of the results and observations of how these practices are developed, it's necessary to evaluate and suggest a logistics to minimize the doses received by OEI during these practices, seeking improvements in the actions and procedures for radiological protection. In practice the production of the radiopharmaceutical, the study focuses on the time of withdrawal of {sup 18}FDG cell processing, where the technician is exposed to higher dose rates. At this stage, we take to accomplish, yet two other reviews: the first is the placement of electronic dosimeters inside and outside the lead apron, whose objective is to assess the attenuation capacity of the apron. This last procedure refers to the use of a phantom cylindrical containing TLD 700 dosimeter in order to evaluate, using a mathematical model (MCNP), the doses ends (hand) of the technician, the process of removing the radiopharmaceutical of the cell and to compare the dosimetric dose recorded in the ring. Regarding the transport of {sup 18}FDG, we take into account the doses recorded in the cabin of the vehicle and the doses recorded in the dosimeter of the carrier. Finally, the doses received by health professionals who handle {sup 18}FDG are analyzed, since its withdrawal from the packing until administration to the patient. (author)

  10. Study of Air Pollution Due to Plasma Cutting Process and Designing Local Ventilation System with Collector in Central Workshop of Mobarakeh Steel Company

    Directory of Open Access Journals (Sweden)

    Farideh Atabi

    2014-06-01

    Full Text Available Background & Objectives : Cutting leads to production of different hazardous agents such as fumes, particles, gases and vapors. In various studies, the effects of fumes, gases, and vapors on workers and environment have been proved. Meanwhile, cutting alloying plates with plasma cutting machine due to containing various alloy materials produces a lot of air pollution. Therefore, using the ventilation system to remove the mentioned pollution has always been noteworthy. Method: This study was performed on plasma cutting machine at Mobarakeh Steel Company. At first, according to ASTM the elements from alloy plates with optical emission spectrometry crm-35000-quantometery were detected, the air pollution from cutting the mentioned plates was sampled and measured using NIOSH 7300 method and according to the ACGIH:VS-72-20, VS-70-12, VS-70-11 VS-916 push-pull ventilation with bag filter collector was designed. Results: Results of sampling from pollution of cutting the alloy material, concentration of iron, lead and cadmium fumes were more than the standard limits. After calculation for push system, air flow volume of 195.163 cfm, outgoing air velocity of 5937.4 fpm and for pull system air flow volume of 12498 cfm, minimum duct velocity of 3000 fpm and velocity pressure of duct of 0.717 inwg, for fan, total pressure of 6.301 inwg, static pressure of 0.587 inwg and power of 20.65 Bhp and for collector with pulse jet cleaning system air to cloth ratio of 7 and dimensions of 6.88ft × 6.56ft × 9.84ft were obtained. Conclusion: The result of study indicated that push pull ventilation compared to other ventilation system s for plasma cutting has more efficiency and makes suitable control for pollution.

  11. Exploring the return-to-work process for workers partially returned to work and partially on long-term sick leave due to common mental disorders: a qualitative study

    NARCIS (Netherlands)

    Noordik, Erik; Nieuwenhuijsen, Karen; Varekamp, Inge; van der Klink, Jac J.; Van Dijk, Frank J.

    2011-01-01

    We conducted a qualitative study into the return-to-work process of workers partially on sick leave due to common mental disorders. Our objectives were to describe the barriers to a full return to work, solutions, communicating to the working environment and the aim of a full return to work, all as

  12. Constitutional Law--Irrebuttable Statutory Presemption of Student Non-Residency Held Violative of Due Process Clause of Fourteenth Amendment--Vlandis v. Kline, 93 S. Ct. 2230 (1973)

    Science.gov (United States)

    University of Richmond Law Review, 1974

    1974-01-01

    In the past the durational residence requirement in colleges and universities has been subject to constitutional challenge under the equal protection clause of the fourteenth amendment. The durational residence requirement in this case displays a further fourteenth amendment vulnerability--the contravention of procedural due process. (Author/PG)

  13. Exploring the return-to-work process for workers partially returned to work and partially on long-term sick leave due to common mental disorders : a qualitative study

    NARCIS (Netherlands)

    Noordik, Erik; Nieuwenhuijsen, Karen; Varekamp, Inge; van der Klink, Jac J.; van Dijk, Frank J.

    2011-01-01

    Purpose. We conducted a qualitative study into the return-to-work process of workers partially on sick leave due to common mental disorders. Our objectives were to describe the barriers to a full return to work, solutions, communicating to the working environment and the aim of a full return to

  14. Initiation process of the Mw 6.2 central Tottori, Japan, earthquake on October 21, 2016: Stress transfer due to its largest foreshock of Mw 4.1

    Science.gov (United States)

    Noda, S.; Ellsworth, W. L.

    2017-12-01

    On October 21, 2016, a strike-slip earthquake with Mw 6.2 occurred in the central Tottori prefecture, Japan. It was preceded by a foreshock sequence that began with a Mw 4.1 event, the largest earthquake for the sequence, and lasted about two hours. According to the JMA catalog, the largest foreshock had a similar focal mechanism as the mainshock and was located in the immediate vicinity of the mainshock hypocenter. The goal of this study is to understand the relationship between the foreshock and the initial rupture of the mainshock. We first determine the relative hypocenter distance between the foreshock and mainshock using the P-wave onsets on Hi-net station records. The initiation points of the two events are likely about 100 m apart according to the current results, but could be closer. Within the location uncertainty, they might either be coplanar or on subparallel planes. Next, we obtain the slip-history models from a kinematic inversion method using empirical Green's functions derived from other foreshocks with M 2.2 - 2.4. The Mw 4.1 foreshock and Mw 6.2 mainshock started in a similar way until approximately 0.2 s after their onsets. For the foreshock, the rapid growth stage completed by 0.2 s even though the rupture propagation continued for 0.4 - 0.5 s longer (note that 0.2 s is significantly shorter than the typical source duration of a Mw 4.1 earthquake). On the other hand, the mainshock rupture continued to grow rapidly after 0.2 s. The comparison between the relative hypocenter locations and the slip models shows that the mainshock nucleated within the area strongly effected by both static and dynamic stress changes created by the foreshock. We also find that the mainshock initially propagated away from the foreshock hypocenter. We consider that the stress transfer process is a key to understand the mainshock nucleation as well as its rupture growth process.

  15. Life cycle assessment applied to two different municipal solid waste processes; Analisi del ciclo di vita di due diverse possibilita' di smaltimento di rifiuti solidi urbani

    Energy Technology Data Exchange (ETDEWEB)

    Corti, A. [Florence Univ., Florence (Italy). Dipt. di Energetica Sergio Stecco; Sirini, P. [Florence Univ., Florence (Italy). Dipt. di Ingegneria Civile

    2001-12-01

    The application of Life Cycle Assessment (LCA) methodology as environmental balance tool is particularly suitable for the study of complex system such as municipal solid waste (MSW) collection, treatment and disposal systems. In this case a detailed analysis is carried out referring to an overall environmental balance based on two different waste treatments: land filling and incineration. The comparison carried out based on the LCA methodology and referring to specific process assumptions allowed to foreground that waste to energy treatments get a net overall balance lower than all the different land filling options, referring also to energy recovery from collected biogas. [Italian] La applicazione di metodologie di bilancio ambientale LCA (Life Cycle Assessment) si adatta particolarmente allo studio disistemi complessi quali quelli di raccolta, trattamento e smaltimento di rifiuti. In questo caso viene affrontata nel dettaglio la valutazione in termini di bilancio complessivo di diverse opzioni di trattamento basate su posa a discarica e trattamento termico. Il confronto effettuato mediante il percorso metodologico seguito, ha permesso di valutare, sulla base delle ipotesi di processi fatte, come il trattamento termico con recupero energetico abbia un bilancio netto ambientale inferiore rispetto a qualsiasi opzione di posa a discarica, anche dotata di recupero energetico dal biogas.

  16. The Net Carbon Flux due to Deforestation and Forest Re-Growth in the Brazilian Amazon: Analysis using a Process-Based Model

    Science.gov (United States)

    Hirsch, A. I.; Little, W. S.; Houghton, R. A.; Scott, N. A.; White, J. D.

    2004-01-01

    We developed a process-based model of forest growth, carbon cycling, and land cover dynamics named CARLUC (for CARbon and Land Use Change) to estimate the size of terrestrial carbon pools in terra firme (non-flooded) forests across the Brazilian Legal Amazon and the net flux of carbon resulting from forest disturbance and forest recovery from disturbance. Our goal in building the model was to construct a relatively simple ecosystem model that would respond to soil and climatic heterogeneity that allows us to study of the impact of Amazonian deforestation, selective logging, and accidental fire on the global carbon cycle. This paper focuses on the net flux caused by deforestation and forest re-growth over the period from 1970-1998. We calculate that the net flux to the atmosphere during this period reached a maximum of approx. 0.35 PgC/yr (1PgC = 1 x 10(exp I5) gC) in 1990, with a cumulative release of approx. 7 PgC from 1970- 1998. The net flux is higher than predicted by an earlier study by a total of 1 PgC over the period 1989-1 998 mainly because CARLUC predicts relatively high mature forest carbon storage compared to the datasets used in the earlier study. Incorporating the dynamics of litter and soil carbon pools into the model increases the cumulative net flux by approx. 1 PgC from 1970-1998, while different assumptions about land cover dynamics only caused small changes. The uncertainty of the net flux, calculated with a Monte-Carlo approach, is roughly 35% of the mean value (1 SD).

  17. Energy driven self-organization in nanoscale metallic liquid films.

    Science.gov (United States)

    Krishna, H; Shirato, N; Favazza, C; Kalyanaraman, R

    2009-10-01

    Nanometre thick metallic liquid films on inert substrates can spontaneously dewet and self-organize into complex nanomorphologies and nanostructures with well-defined length scales. Nanosecond pulses of an ultraviolet laser can capture the dewetting evolution and ensuing nanomorphologies, as well as introduce dramatic changes to dewetting length scales due to the nanoscopic nature of film heating. Here, we show theoretically that the self-organization principle, based on equating the rate of transfer of thermodynamic free energy to rate of loss in liquid flow, accurately describes the spontaneous dewetting. Experimental measurements of laser dewetting of Ag and Co liquid films on SiO(2) substrates confirm this principle. This energy transfer approach could be useful for analyzing the behavior of nanomaterials and chemical processes in which spontaneous changes are important.

  18. Human due diligence.

    Science.gov (United States)

    Harding, David; Rouse, Ted

    2007-04-01

    Most companies do a thorough job of financial due diligence when they acquire other companies. But all too often, deal makers simply ignore or underestimate the significance of people issues in mergers and acquisitions. The consequences are severe. Most obviously, there's a high degree of talent loss after a deal's announcement. To make matters worse, differences in decision-making styles lead to infighting; integration stalls; and productivity declines. The good news is that human due diligence can help companies avoid these problems. Done early enough, it helps acquirers decide whether to embrace or kill a deal and determine the price they are willing to pay. It also lays the groundwork for smooth integration. When acquirers have done their homework, they can uncover capability gaps, points of friction, and differences in decision making. Even more important, they can make the critical "people" decisions-who stays, who goes, who runs the combined business, what to do with the rank and file-at the time the deal is announced or shortly thereafter. Making such decisions within the first 30 days is critical to the success of a deal. Hostile situations clearly make things more difficult, but companies can and must still do a certain amount of human due diligence to reduce the inevitable fallout from the acquisition process and smooth the integration. This article details the steps involved in conducting human due diligence. The approach is structured around answering five basic questions: Who is the cultural acquirer? What kind of organization do you want? Will the two cultures mesh? Who are the people you most want to retain? And how will rank-and-file employees react to the deal? Unless an acquiring company has answered these questions to its satisfaction, the acquisition it is making will be very likely to end badly.

  19. 34 CFR 602.25 - Due process.

    Science.gov (United States)

    2010-07-01

    ... before an appeals panel that— (i) May not include current members of the agency's decision-making body... significance and materiality are determined by the agency. (iii) The only remaining deficiency cited by the...

  20. The Drone Court And Due Process

    Science.gov (United States)

    2016-12-01

    authority, even during wartime, when it heard Youngstown Tube and Sheet Co. v. Sawyer.68 In 1951, when the United States went to war with Korea , labor...national origin, religion , alienage, and poverty.” See “Strict Scrutiny,” Legal Information Institute, accessed December 9, 2016, https

  1. Process Recovery after CaO Addition Due to Granule Formation in a CSTR Co-Digester—A Tool to Influence the Composition of the Microbial Community and Stabilize the Process?

    Science.gov (United States)

    Liebrich, Marietta; Kleyböcker, Anne; Kasina, Monika; Miethling-Graff, Rona; Kassahun, Andrea; Würdemann, Hilke

    2016-01-01

    The composition, structure and function of granules formed during process recovery with calcium oxide in a laboratory-scale fermenter fed with sewage sludge and rapeseed oil were studied. In the course of over-acidification and successful process recovery, only minor changes were observed in the bacterial community of the digestate, while granules appeared during recovery. Fluorescence microscopic analysis of the granules showed a close spatial relationship between calcium and oil and/or long chain fatty acids. This finding further substantiated the hypothesis that calcium precipitated with carbon of organic origin and reduced the negative effects of overloading with oil. Furthermore, the enrichment of phosphate minerals in the granules was shown, and molecular biological analyses detected polyphosphate-accumulating organisms as well as methanogenic archaea in the core. Organisms related to Methanoculleus receptaculi were detected in the inner zones of a granule, whereas they were present in the digestate only after process recovery. This finding indicated more favorable microhabitats inside the granules that supported process recovery. Thus, the granule formation triggered by calcium oxide addition served as a tool to influence the composition of the microbial community and to stabilize the process after overloading with oil. PMID:27681911

  2. Process Recovery after CaO Addition Due to Granule Formation in a CSTR Co-Digester-A Tool to Influence the Composition of the Microbial Community and Stabilize the Process?

    Science.gov (United States)

    Liebrich, Marietta; Kleyböcker, Anne; Kasina, Monika; Miethling-Graff, Rona; Kassahun, Andrea; Würdemann, Hilke

    2016-03-17

    The composition, structure and function of granules formed during process recovery with calcium oxide in a laboratory-scale fermenter fed with sewage sludge and rapeseed oil were studied. In the course of over-acidification and successful process recovery, only minor changes were observed in the bacterial community of the digestate, while granules appeared during recovery. Fluorescence microscopic analysis of the granules showed a close spatial relationship between calcium and oil and/or long chain fatty acids. This finding further substantiated the hypothesis that calcium precipitated with carbon of organic origin and reduced the negative effects of overloading with oil. Furthermore, the enrichment of phosphate minerals in the granules was shown, and molecular biological analyses detected polyphosphate-accumulating organisms as well as methanogenic archaea in the core. Organisms related to Methanoculleus receptaculi were detected in the inner zones of a granule, whereas they were present in the digestate only after process recovery. This finding indicated more favorable microhabitats inside the granules that supported process recovery. Thus, the granule formation triggered by calcium oxide addition served as a tool to influence the composition of the microbial community and to stabilize the process after overloading with oil.

  3. Process Recovery after CaO Addition Due to Granule Formation in a CSTR Co-Digester—A Tool to Influence the Composition of the Microbial Community and Stabilize the Process?

    Directory of Open Access Journals (Sweden)

    Marietta Liebrich

    2016-03-01

    Full Text Available The composition, structure and function of granules formed during process recovery with calcium oxide in a laboratory-scale fermenter fed with sewage sludge and rapeseed oil were studied. In the course of over-acidification and successful process recovery, only minor changes were observed in the bacterial community of the digestate, while granules appeared during recovery. Fluorescence microscopic analysis of the granules showed a close spatial relationship between calcium and oil and/or long chain fatty acids. This finding further substantiated the hypothesis that calcium precipitated with carbon of organic origin and reduced the negative effects of overloading with oil. Furthermore, the enrichment of phosphate minerals in the granules was shown, and molecular biological analyses detected polyphosphate-accumulating organisms as well as methanogenic archaea in the core. Organisms related to Methanoculleus receptaculi were detected in the inner zones of a granule, whereas they were present in the digestate only after process recovery. This finding indicated more favorable microhabitats inside the granules that supported process recovery. Thus, the granule formation triggered by calcium oxide addition served as a tool to influence the composition of the microbial community and to stabilize the process after overloading with oil.

  4. Effect of Systematic Control of Pd Thickness and Annealing Temperature on the Fabrication and Evolution of Palladium Nanostructures on Si (111) via the Solid State Dewetting.

    Science.gov (United States)

    Kunwar, Sundar; Pandey, Puran; Sui, Mao; Zhang, Quanzhen; Li, Ming-Yu; Lee, Jihoon

    2017-12-01

    Si-based optoelectronic devices embedded with metallic nanoparticles (NPs) have demonstrated the NP shape, size, spacing, and crystallinity dependent on light absorption and emission induced by the localized surface plasmon resonance. In this work, we demonstrate various sizes and configurations of palladium (Pd) nanostructures on Si (111) by the systematic thermal annealing with the variation of Pd thickness and annealing temperature. The evolution of Pd nanostructures are systematically controlled by the dewetting of thin film by means of the surface diffusion in conjunction with the surface and interface energy minimization and Volmer-Weber growth model. Depending on the control of deposition amount ranging between 0.5 and 100 nm at various annealing temperatures, four distinctive regimes of Pd nanostructures are demonstrated: (i) small pits and grain formation, (ii) nucleation and growth of NPs, (iii) lateral evolution of NPs, and (iv) merged nanostructures. In addition, by the control of annealing between 300 and 800 °C, the Pd nanostructures show the evolution of small pits and grains, isolated NPs, and finally, Pd NP-assisted nanohole formation along with the Si decomposition and Pd-Si inter-diffusion. The Raman analysis showed the discrepancies on phonon modes of Si (111) such that the decreased peak intensity with left shift after the fabrication of Pd nanostructures. Furthermore, the UV-VIS-NIR reflectance spectra revealed the existence of surface morphology dependent on absorption, scattering, and reflectance properties.

  5. Solution-processed flexible NiO resistive random access memory device

    Science.gov (United States)

    Kim, Soo-Jung; Lee, Heon; Hong, Sung-Hoon

    2018-04-01

    Non-volatile memories (NVMs) using nanocrystals (NCs) as active materials can be applied to soft electronic devices requiring a low-temperature process because NCs do not require a heat treatment process for crystallization. In addition, memory devices can be implemented simply by using a patterning technique using a solution process. In this study, a flexible NiO ReRAM device was fabricated using a simple NC patterning method that controls the capillary force and dewetting of a NiO NC solution at low temperature. The switching behavior of a NiO NC based memory was clearly observed by conductive atomic force microscopy (c-AFM).

  6. Influences of poly[(styrene){sub x}-stat-(chloromethylstyrene){sub y}]s additives on dewetting behaviors of polystyrene thin films: effects of polar group ratio and film thickness

    Energy Technology Data Exchange (ETDEWEB)

    Sangjan, Suntree [Research Unit of Advanced Ceramics, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Traiphol, Nisanart, E-mail: Nisanart.T@chula.ac.th [Research Unit of Advanced Ceramics, Department of Materials Science, Faculty of Science, Chulalongkorn University, Bangkok 10330 (Thailand); Center for Petroleum, Petrochemical, and Advanced Materials, Chulalongkorn University, Bangkok 10330 (Thailand); Traiphol, Rakchart, E-mail: Rakchartt@nu.ac.th [Laboratory of Advanced Polymers and Nanomaterials, Department of Chemistry and Center of Excellence for Innovation in Chemistry, Faculty of Science, Naresuan University, Phitsanulok 65000 (Thailand); NANOTEC Center of Excellence at Mahidol University, Rama 6 Road, Ratchathewi, Bangkok 10400 (Thailand)

    2012-05-31

    This contribution investigates the addition of poly(styrene-stat-chloromethylstyrene (ClMS))s as dewetting inhibitors of polystyrene (PS) thin films with thicknesses ranging from 12 to 38 nm. The ClMS ratios in the copolymers are 5, 25 and 45 mol%. Atomic force microscopy and optical microscopy are utilized to follow morphological changes of blended PS/copolymer films upon annealing above their glass transition temperatures. We have found that thermal stability of the PS films is greatly improved when a small amount of the copolymers is added into the system. The polar ClMS groups provide anchoring sites with the polar SiO{sub x}/Si substrate while the styrene segments favorably interact with the PS matrix. The effectiveness of the copolymers as dewetting inhibitors is also found to increase with mole ratio of ClMS group. While the stability of PS films is systematically improved upon addition of the highly substituted copolymers, using the copolymer with relatively low ratio of ClMS group could lead to the opposite result. This class of copolymers can be utilized for improving thermal stability of ultrathin PS films. The fundamental knowledge from this study is also important for designing or selecting structure of additives used to improve the stability of polymeric thin films. - Highlights: Black-Right-Pointing-Pointer Efficient method for improving stability of polystyrene (PS) thin films. Black-Right-Pointing-Pointer Poly(styrene-stat-chloromethylstyrene)s are used as dewetting inhibitors. Black-Right-Pointing-Pointer Thermal stability of blended PS/copolymers greatly improved. Black-Right-Pointing-Pointer Effectiveness of the copolymers increases with mole ratio of chloromethylstyrene group. Black-Right-Pointing-Pointer Important results for designing materials in coating application.

  7. DECOVALEX-THMC Task D: Long-Term Permeability/Porosity Changes in the EDZ and Near Field due to THM and THC Processes in Volcanic and Crystalline-Bentonite Systems, Status Report October 2005

    International Nuclear Information System (INIS)

    Birkholzer, J.; Rutqvist, J.; Sonnenthal, E.; Barr, D.

    2005-01-01

    The DECOVALEX project is an international cooperative project initiated by SKI, the Swedish Nuclear Power Inspectorate, with participation of about 10 international organizations. The name DECOVALEX stands for DEvelopment of COupled models and their VALidation against Experiments. The general goal of this project is to encourage multidisciplinary interactive and cooperative research on modeling coupled processes in geologic formations in support of the performance assessment for underground storage of radioactive waste. Three multi-year project stages of DECOVALEX have been completed in the past decade, mainly focusing on coupled thermal-hydrological-mechanical processes. Currently, a fourth three-year project stage of DECOVALEX is under way, referred to as DECOVALEX-THMC. THMC stands for Thermal, Hydrological, Mechanical, and Chemical processes. The new project stage aims at expanding the traditional geomechanical scope of the previous DECOVALEX project stages by incorporating geochemical processes important for repository performance. The U.S. Department of Energy (DOE) leads Task D of the new DECOVALEX phase, entitled ''Long-term Permeability/Porosity Changes in the EDZ and Near Field due to THC and THM Processes for Volcanic and Crystalline-Bentonite Systems''. In its leadership role for Task D, DOE coordinates and sets the direction for the cooperative research activities of the international research teams engaged in Task D

  8. Diplopia due to Dacryops

    Directory of Open Access Journals (Sweden)

    Rahmi Duman

    2013-01-01

    Full Text Available Dacryops is a lacrimal ductal cyst. It is known that it can cause globe displacement, motility restriction, and proptosis because of the mass effect. Diplopia due to dacryops has not been reported previously. Here, we present a 57-year-old man with binocular horizontal diplopia that occurred during left direction gaze due to dacryops.

  9. Dynamically slow processes in supercooled water confined between hydrophobic plates

    Energy Technology Data Exchange (ETDEWEB)

    Franzese, Giancarlo [Departamento de Fisica Fundamental, Universidad de Barcelona, Diagonal 647, Barcelona 08028 (Spain); Santos, Francisco de los, E-mail: gfranzese@ub.ed, E-mail: fdlsant@ugr.e [Departamento de Electromagnetismo y Fisica de la Materia, Universidad de Granada, Fuentenueva s/n, 18071 Granada (Spain)

    2009-12-16

    We study the dynamics of water confined between hydrophobic flat surfaces at low temperature. At different pressures, we observe different behaviors that we understand in terms of the hydrogen bond dynamics. At high pressure, the formation of the open structure of the hydrogen bond network is inhibited and the surfaces can be rapidly dried (dewetted) by formation of a large cavity with decreasing temperature. At lower pressure we observe strong non-exponential behavior of the correlation function, but with no strong increase of the correlation time. This behavior can be associated, on the one hand, to the rapid ordering of the hydrogen bonds that generates heterogeneities and, on the other hand, to the lack of a single timescale as a consequence of the cooperativity in the vicinity of the liquid-liquid critical point that characterizes the phase diagram at low temperature of the water model considered here. At very low pressures, the gradual formation of the hydrogen bond network is responsible for the large increase of the correlation time and, eventually, the dynamical arrest of the system, with a strikingly different dewetting process, characterized by the formation of many small cavities.

  10. Dynamically slow processes in supercooled water confined between hydrophobic plates

    International Nuclear Information System (INIS)

    Franzese, Giancarlo; Santos, Francisco de los

    2009-01-01

    We study the dynamics of water confined between hydrophobic flat surfaces at low temperature. At different pressures, we observe different behaviors that we understand in terms of the hydrogen bond dynamics. At high pressure, the formation of the open structure of the hydrogen bond network is inhibited and the surfaces can be rapidly dried (dewetted) by formation of a large cavity with decreasing temperature. At lower pressure we observe strong non-exponential behavior of the correlation function, but with no strong increase of the correlation time. This behavior can be associated, on the one hand, to the rapid ordering of the hydrogen bonds that generates heterogeneities and, on the other hand, to the lack of a single timescale as a consequence of the cooperativity in the vicinity of the liquid-liquid critical point that characterizes the phase diagram at low temperature of the water model considered here. At very low pressures, the gradual formation of the hydrogen bond network is responsible for the large increase of the correlation time and, eventually, the dynamical arrest of the system, with a strikingly different dewetting process, characterized by the formation of many small cavities.

  11. DECOVALEX-THMC Project. Task D. Long-Term Permeability/Porosity Changes in the EDZ and Near Field due to THM and THC Processes in Volcanic and Crystalline-Bentonite Systems. Phase 1 Report

    International Nuclear Information System (INIS)

    Birkholzer, J.; Rutqvist, J.; Sonnenthal, E.; Barr, D.

    2007-02-01

    The general goal of this project is to encourage multidisciplinary interactive and cooperative research on modeling coupled processes in geologic formations in support of the performance assessment for underground storage of radioactive waste. Three multi-year project stages of DECOVALEX have been completed in the past decade, mainly focusing on coupled thermal-hydrological-mechanical processes. Currently, a fourth three-year project stage of DECOVALEX is under way, referred to as DECOVALEX-THMC. THMC stands for Thermal, Hydrological, Mechanical, and Chemical processes. The new project stage aims at expanding the traditional geomechanical scope of the previous DECOVALEX project stages by incorporating geochemical processes important for repository performance. The U.S. Department of Energy (DOE) leads Task D of the new DECOVALEX phase, entitled 'Long-term Permeability/Porosity Changes in the EDZ and Near Field due to THC and THM Processes for Volcanic and Crystalline-Bentonite Systems.' In its leadership role for Task D, DOE coordinates and sets the direction for the cooperative research activities of the international research teams engaged in Task D. The research program developed for Task D of DECOVALEX-THMC involves geomechanical and geochemical research areas. THM and THC processes may lead to changes in hydrological properties that are important for performance because the flow processes in the vicinity of emplacement tunnels will be altered from their initial state. Some of these changes can be permanent (irreversible), in which case they persist after the thermal conditions have returned to ambient; i.e., they will affect the entire regulatory compliance period. Geochemical processes also affect the water and gas chemistry close to the waste packages, which are relevant for waste package corrosion, buffer stability, and radionuclide transport. Research teams participating in Task D evaluate long-term THM and THC processes in two generic geologic

  12. DECOVALEX-THMC Project. Task D. Long-Term Permeability/Porosity Changes in the EDZ and Near Field due to THM and THC Processes in Volcanic and Crystalline-Bentonite Systems. Phase 1 Report

    Energy Technology Data Exchange (ETDEWEB)

    Birkholzer, J.; Rutqvist, J.; Sonnenthal, E. [Lawrence Berkeley National Laboratory, CA (United States); Barr, D. [Office of Repository Development, DOE (United States)

    2007-02-15

    The general goal of this project is to encourage multidisciplinary interactive and cooperative research on modeling coupled processes in geologic formations in support of the performance assessment for underground storage of radioactive waste. Three multi-year project stages of DECOVALEX have been completed in the past decade, mainly focusing on coupled thermal-hydrological-mechanical processes. Currently, a fourth three-year project stage of DECOVALEX is under way, referred to as DECOVALEX-THMC. THMC stands for Thermal, Hydrological, Mechanical, and Chemical processes. The new project stage aims at expanding the traditional geomechanical scope of the previous DECOVALEX project stages by incorporating geochemical processes important for repository performance. The U.S. Department of Energy (DOE) leads Task D of the new DECOVALEX phase, entitled 'Long-term Permeability/Porosity Changes in the EDZ and Near Field due to THC and THM Processes for Volcanic and Crystalline-Bentonite Systems.' In its leadership role for Task D, DOE coordinates and sets the direction for the cooperative research activities of the international research teams engaged in Task D. The research program developed for Task D of DECOVALEX-THMC involves geomechanical and geochemical research areas. THM and THC processes may lead to changes in hydrological properties that are important for performance because the flow processes in the vicinity of emplacement tunnels will be altered from their initial state. Some of these changes can be permanent (irreversible), in which case they persist after the thermal conditions have returned to ambient; i.e., they will affect the entire regulatory compliance period. Geochemical processes also affect the water and gas chemistry close to the waste packages, which are relevant for waste package corrosion, buffer stability, and radionuclide transport. Research teams participating in Task D evaluate long-term THM and THC processes in two generic geologic

  13. Panhypopituitarism Due to Hemochromatosis

    OpenAIRE

    Mesut Özkaya; Kadir Gis; Ali Çetinkaya

    2013-01-01

    Hemochromatosis is an iron storage disease. Panhypopituitarism is a clinical condition in which the anterior pituitary hormones are deficient. Herein, we report a rare case of panhypopituitarism due to hemochromatosis. Turk Jem 2013; 17: 125-6

  14. Exploring factors relevant in the assessment of the return-to-work process of employees on long-term sickness absence due to a depressive disorder: a focus group study

    Directory of Open Access Journals (Sweden)

    Muijzer Anna

    2012-02-01

    Full Text Available Abstract Background Efforts undertaken during the Return-to-Work (RTW process need to be sufficient in order to optimize the quality of the RTW process. The purpose of this study was to explore factors relevant to Return-to-Work Effort Sufficiency (RTW-ES in cases of sick-listed employees with a Depressive Disorder (DD. Method A case of a long-term sick-listed employee with a DD applying for disability benefits was used to gather arguments and grounds relevant to the assessment of RTW-ES. Two focus group meetings were held, consisting of Labor Experts working at the Dutch Social Insurance Institute. Factors were collected and categorized using the International Classification of Functioning, Disability and Health (ICF model. Results Sixteen factors relevant to RTW-ES assessment in a case of DD were found, categorized in the ICF-model under activities (e.g. functional capacity, personal (e.g. competencies, attitude and environmental domain (e.g. employer-employee relationship, or categorized under interventions, job accommodations and measures. Conclusions This study shows that 16 factors are relevant in the assessment of RTW-ES in employees sick-listed due to DD. Further research is necessary to expand this knowledge to other health conditions, and to investigate the impact of these results on the quality of the RTW-ES assessment.

  15. Injury due to thorotrast

    International Nuclear Information System (INIS)

    Mori, Takesaburo

    1976-01-01

    A synthetic study was performed on some of those to whom Thorotrast had been injected, in Japan. In the epidemiological study of 147 war woundeds to whom Thorotrast had been injected, it was noted that the Thorotrast injection increased the mortality rate and the incidences of malignant hepatic tumor, liver cirrhosis, and hematological diseases. Clinical study of 44 of them showed that the Thorotrast injection resulted in liver and hematopoietic hypofunctions. Analysis of the dissection of the injected area in 118 cases showed malignant hepatic tumor in 63.5%, liver cirrhosis in 14.4% and hematological diseases in 10.2%. The total of the three types of disease was 88.1%. Histological classification showed that of the malignant hepatic tumors due to Thorotrast, hepatobiliary cancer and hemangioendothelioma of the liver were frequent. By the comparison of the absorbed dose in the liver of the malignant hepatic tumors due to Thorotrast with that of the cancers developed in animal experiments, it was noted that the carcinogenic dose was a mean of 2,000 - 3,000 rad by accumulated dose. It was elucidated that carcinogenesis and fibrination were primary in injury due to Thorotrast, i.e., late injury due to Thorotrast, and that the increase in the accumulated dose in rogans and the increase of the local dose due to the gigantic growth of Thorotrast granules in organs greatly influenced carninogenesis and fibrination. (Chiba, N.)

  16. Anaphylaxis due to caffeine

    OpenAIRE

    Sugiyama, Kumiya; Cho, Tatsurai; Tatewaki, Masamitsu; Onishi, Shogo; Yokoyama, Tatsuya; Yoshida, Naruo; Fujimatsu, Takayoshi; Hirata, Hirokuni; Fukuda, Takeshi; Fukushima, Yasutsugu

    2015-01-01

    We report a rare case of anaphylaxis due to caffeine intake. A 27-year-old woman suffered her first episode of anaphylaxis and a positive skin prick test suggested that the anaphylaxis was due to an IgE-mediated hypersensitivity reaction to caffeine. She was diagnosed with caffeine allergy and has not had an allergic reaction after avoiding foods and drinks containing caffeine. Although caffeine is known to have antiallergic effects, this case shows that caffeine can be an allergen and cause ...

  17. Technical Due Diligence

    DEFF Research Database (Denmark)

    Jensen, Per Anker; Varano, Mattia

    2011-01-01

    carried out for buyers or sellers involved in real estate transactions. It can also be part of mergers including real estate and other assets or part of facilities management outsourcing. This paper is based on a case study and an interview survey of companies involved in TDD consulting in Denmark......Technical Due Diligence (TDD) as an evaluation of the performance of constructed facilities has become an important new field of practice for consultants. Before the financial crisis started in autumn 2008 it represented the fastest growing activity in some consulting companies. TDD is mostly...... and Italy during 2009. The research identifies the current practice and compares it with the recommended practice in international guidelines. The current practice is very diverse and could in many cases be improved by a more structured approach and stricter adherence to international guidelines. However...

  18. Exploring factors relevant in the assessment of the return-to-work process of employees on long-term sickness absence due to a depressive disorder : a focus group study

    NARCIS (Netherlands)

    Muijzer, Anna; Brouwer, Sandra; Geertzen, Jan H.; Groothoff, Johan W.

    2012-01-01

    Background: Efforts undertaken during the Return-to-Work (RTW) process need to be sufficient in order to optimize the quality of the RTW process. The purpose of this study was to explore factors relevant to Return-to-Work Effort Sufficiency (RTW-ES) in cases of sick-listed employees with a

  19. In situ laser processing in a scanning electron microscope

    Energy Technology Data Exchange (ETDEWEB)

    Roberts, Nicholas A.; Magel, Gregory A.; Hartfield, Cheryl D.; Moore, Thomas M.; Fowlkes, Jason D.; Rack, Philip D. [Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States) and Omniprobe, Inc., an Oxford Instruments Company, 10410 Miller Rd., Dallas, Texas 75238 (United States); Omniprobe, Inc., an Oxford Instruments Company, 10410 Miller Rd., Dallas, Texas 75238 (United States); Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States); Department of Materials Science and Engineering, University of Tennessee, Knoxville, Tennessee 37996 (United States) and Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)

    2012-07-15

    Laser delivery probes using multimode fiber optic delivery and bulk focusing optics have been constructed and used for performing materials processing experiments within scanning electron microscope/focused ion beam instruments. Controlling the current driving a 915-nm semiconductor diode laser module enables continuous or pulsed operation down to sub-microsecond durations, and with spot sizes on the order of 50 {mu}m diameter, achieving irradiances at a sample surface exceeding 1 MW/cm{sup 2}. Localized laser heating has been used to demonstrate laser chemical vapor deposition of Pt, surface melting of silicon, enhanced purity, and resistivity via laser annealing of Au deposits formed by electron beam induced deposition, and in situ secondary electron imaging of laser induced dewetting of Au metal films on SiO{sub x}.

  20. A Mathematical Model for Scheduling a Batch Processing Machine with Multiple Incompatible Job Families, Non-identical Job dimensions, Non-identical Job sizes, Non-agreeable release times and due dates

    International Nuclear Information System (INIS)

    Ramasubramaniam, M; Mathirajan, M

    2013-01-01

    The paper addresses the problem scheduling a batch processing machine with multiple incompatible job families, non-identical job dimensions, non-identical job sizes and non-agreeable release dates to minimize makespan. The research problem is solved by proposing a mixed integer programming model that appropriately takes into account the parameters considered in the problem. The proposed is validated using a numerical example. The experiment conducted show that the model can pose significant difficulties in solving the large scale instances. The paper concludes by giving the scope for future work and some alternative approaches one can use for solving these class of problems.

  1. Qubit dephasing due to quasiparticle tunneling

    Energy Technology Data Exchange (ETDEWEB)

    Zanker, Sebastian; Marthaler, Michael; Schoen, Gerd [Institut fuer Theoretische Festkoerperphysik, Karlsruhe Institute of Technology, D-76128 Karlsruhe (Germany)

    2015-07-01

    We study dephasing of a superconducting qubit due to quasiparticle tunneling through a Josephson junction. While qubit decay due to tunneling processes is well understood within a golden rule approximation, pure dephasing due to BCS quasiparticles gives rise to a divergent golden rule rate. We calculate qubit dephasing due to quasiparticle tunneling beyond lowest order approximation in coupling between qubit and quasiparticles. Summing up a certain class of diagrams we show that qubit dephasing due to purely longitudinal coupling to quasiparticles leads to dephasing ∝ exp(-x(t)) where x(t) ∝ t{sup 3/2} for short time scales and x(t) ∝ tlog(t) for long time scales.

  2. [On Atomic Nuclear Fusion Processes at Low-Temperatures. An Enhancement of the Probability of Transition through a Potential Barrier Due to the So-Called Barrier Anti-Zeno Effect].

    Science.gov (United States)

    Namiot, V A

    2016-01-01

    It is known that in quantum mechanics the act of observing the experiment can affect the experimental findings in some cases. In particular, it happens under the so-called Zeno effect. In this work it is shown that in contrast to the "standard" Zeno-effect where the act of observing a process reduces the probability of its reality, an inverse situation when a particle transmits through a potential barrier (a so-called barrier anti-Zeno effect) can be observed, the observation of the particle essentially increases the probability of its transmission through the barrier. The possibility of using the barrier anti-Zeno effect is discussed to explain paradoxical results of experiments on "cold nuclear fusion" observed in various systems including biological ones. (According to the observers who performed the observations, the energy generation, which could not be explained by any chemical processes, as well as the change in the isotope and even element composition of the studied object may occur in these systems.

  3. The Absence of the Transcription Factor Yrr1p, Identified from Comparative Genome Profiling, Increased Vanillin Tolerance Due to Enhancements of ABC Transporters Expressing, rRNA Processing and Ribosome Biogenesis in Saccharomyces cerevisiae.

    Science.gov (United States)

    Wang, Xinning; Liang, Zhenzhen; Hou, Jin; Shen, Yu; Bao, Xiaoming

    2017-01-01

    Enhancing the tolerance of Saccharomyces cerevisiae to inhibitors derived from lignocellulose is conducive to producing biofuel and chemicals using abundant lignocellulosic materials. Vanillin is a major type of phenolic inhibitor in lignocellulose hydrolysates for S. cerevisiae . In the present work, the factors beneficial to vanillin resistance in yeast were identified from the vanillin-resistant strain EMV-8, which was derived from strain NAN-27 by adaptive evolution. We found 450 SNPs and 44 genes with InDels in the vanillin-tolerant strain EMV-8 by comparing the genome sequences of EMV-8 and NAN-27. To investigate the effects of InDels, InDels were deleted in BY4741, respectively. We demonstrated that the deletion of YRR1 improved vanillin tolerance of strain. In the presence of 6 mM vanillin, deleting YRR1 increase the maximum specific growth rate and the vanillin consumption rate by 142 and 51%, respectively. The subsequent transcriptome analysis revealed that deleting YRR1 resulted in changed expression of over 200 genes in the presence of 5 mM vanillin. The most marked changes were the significant up-regulation of the dehydrogenase ADH7 , several ATP-binding cassette (ABC) transporters, and dozens of genes involved in ribosome biogenesis and rRNA processing. Coincidently, the crude enzyme solution of BY4741( yrr1 Δ) exhibited higher NADPH-dependent vanillin reduction activity than control. In addition, overexpressing the ABC transporter genes PDR5, YOR1 , and SNQ2 , as well as the RNA helicase gene DBP2 , increased the vanillin tolerance of strain. Interestingly, unlike the marked changes we mentioned above, under vanillin-free conditions, there are only limited transcriptional differences between wildtype and yrr1 Δ. This indicated that vanillin might act as an effector in Yrr1p-related regulatory processes. The new findings of the relationship between YRR1 and vanillin tolerance, as well as the contribution of rRNA processing and ribosome biogenesis to

  4. Macrocluster desorption effect caused by single MCI: charges of gold clusters (2-20 nm) desorbed due to electronic processes induced by fission fragment bombardment in nanodispersed gold targets

    International Nuclear Information System (INIS)

    Baranov, I.; Jarmiychuk, S.; Kirillov, S.; Novikov, A.; Obnorskii, V.; Pchelintsev, A.; Wien, K.; Reimann, C.

    1999-01-01

    In this work the charge state of the negatively charged gold nanocluster ions (2-20 nm) that were desorbed from nanodispersed gold islet targets by 252 Cf fission fragments via electronic processes is studied. Mean cluster charge was calculated as a ratio of mean cluster mass to mean mass-to-charge ratio . Cluster masses were measured by means of a collector technique employing transmission electron microscopy and scanning force microscopy, while m/q was measured by means of a tandem TOF-spectrometer. It is shown that the nanocluster ions are mostly multiply charged (2-16e) and the charge increases non-linearly with the cluster size. The results are discussed

  5. Flow Rate Capacity Reduction Due to Temporal and Dynamic Processes in Large Pipelines. Study with Field Measurements; Efectos dinamicos y temporales en la reduccion de la capacidad de conduccion en grandes acueductos. Estudio con medidas en prototipo

    Energy Technology Data Exchange (ETDEWEB)

    Carmona Paredes, Rafael; Ortiz Nunez, Luis Alfonso; Sanchez Huerta, Alejandro [Universidad Nacional Autonoma de Mexico (Mexico)

    2002-06-01

    More than 15 years of operation have show that some water transport pressurized pipelines change their flow rate capacity faster than expected due to normal roughness increase. As explained by the tubular pinch effects, the radial migration of suspended particles in a flow can produce a high concentration close to the pipe wall. The non-uniform particle concentration leads to higher velocities at the center of the tube, equivalent to a reduced hydraulic section that increases the head losses. A model to explain field measurements at the Chapala-Guadalajara Aqueduct is proposed that suggests to hydraulic engineers to be more distrustful when using traditional head loss formulas to analyze water transport pipelines. [Spanish] La perdida de la capacidad de conduccion es un grave problema en la operacion de grandes acueductos. Mas de 15 anos de estudios y de inspeccion directa al interior de las tuberias de varios sistemas de abastecimiento de agua potable han mostrado el desarrollo de capas de material fino fuertemente adheridas a la pared de los tubos. En algunos casos, la variacion de la perdida de carga no ha podido ser explicada con los modelos tradicionales de crecimiento de la rugosidad interna, por lo que para explicar de forma adecuada las mediciones de campo realizadas en el acueducto Chapala-Guadalajara ha sido necesario incorporar de manera simultanea fenomenos dinamicos y temporales. Con base en el fecto de elongacion tubular (o tubular pinch effect), descrito por otros autores, mas observaciones directas al interior de las tuberias, en este trabajo se plantea como una posible de la disminucion de capacidad de conduccion en el acueducto Chapala-Guadalajara un cambio aparente en la seccion efectiva del flujo, originado por la migracion radial hacia la pared del tubo de las particulas suspendidas en el agua. El modelo que propone reproduce las medidas en campo con diferencias menores al 10% e invita a reflexionar sobre las practicas convencionales para

  6. Dynamics of ultrathin metal films on amorphous substrates under fast thermal processing

    International Nuclear Information System (INIS)

    Favazza, Christopher; Kalyanaraman, Ramki; Sureshkumar, Radhakrishna

    2007-01-01

    A mathematical model is developed to analyze the growth/decay rate of surface perturbations of an ultrathin metal film on an amorphous substrate (SiO 2 ). The formulation combines the approach of Mullins [W. W. Mullins, J. Appl. Phys. 30, 77 (1959)] for bulk surfaces, in which curvature-driven mass transport and surface deformation can occur by surface/volume diffusion and evaporation-condensation processes, with that of Spencer et al. [B. J. Spencer, P. W. Voorhees, and S. H. Davis, Phys. Rev. Lett. 67, 26 (1991)] to describe solid-state transport in thin films under epitaxial strain. Modifications of the Mullins model to account for thin-film boundary conditions result in qualitatively different dispersion relationships especially in the limit as kh o o is the unperturbed film height. The model is applied to study the relative rate of solid-state mass transport as compared to that of liquid phase dewetting in a thin film subjected to a fast thermal pulse. Specifically, we have recently shown that multiple cycles of nanosecond (ns) pulsed laser melting and resolidification of ultrathin metal films on amorphous substrates can lead to the formation of various types of spatially ordered nanostructures [J. Trice, D. Thomas, C. Favazza, R. Sureshkumar, and R. Kalyanaraman, Phys. Rev. B 75, 235439 (2007)]. The pattern formation has been attributed to the dewetting of the thin film by a hydrodynamic instability. In such experiments the film is in the solid state during a substantial fraction of each thermal cycle. However, results of a linear stability analysis based on the aforementioned model suggest that solid-state mass transport has a negligible effect on morphological changes of the surface. Further, a qualitative analysis of the effect of thermoelastic stress, induced by the rapid temperature changes in the film-substrate bilayer, suggests that stress relaxation does not appreciably contribute to surface deformation. Hence, surface deformation caused by liquid

  7. Dynamics of ultrathin metal films on amorphous substrates under fast thermal processing

    Science.gov (United States)

    Favazza, Christopher; Kalyanaraman, Ramki; Sureshkumar, Radhakrishna

    2007-11-01

    A mathematical model is developed to analyze the growth/decay rate of surface perturbations of an ultrathin metal film on an amorphous substrate (SiO2). The formulation combines the approach of Mullins [W. W. Mullins, J. Appl. Phys. 30, 77 (1959)] for bulk surfaces, in which curvature-driven mass transport and surface deformation can occur by surface/volume diffusion and evaporation-condensation processes, with that of Spencer etal . [B. J. Spencer, P. W. Voorhees, and S. H. Davis, Phys. Rev. Lett. 67, 26 (1991)] to describe solid-state transport in thin films under epitaxial strain. Modifications of the Mullins model to account for thin-film boundary conditions result in qualitatively different dispersion relationships especially in the limit as kho≪1, where k is the wavenumber of the perturbation and ho is the unperturbed film height. The model is applied to study the relative rate of solid-state mass transport as compared to that of liquid phase dewetting in a thin film subjected to a fast thermal pulse. Specifically, we have recently shown that multiple cycles of nanosecond (ns) pulsed laser melting and resolidification of ultrathin metal films on amorphous substrates can lead to the formation of various types of spatially ordered nanostructures [J. Trice, D. Thomas, C. Favazza, R. Sureshkumar, and R. Kalyanaraman, Phys. Rev. B 75, 235439 (2007)]. The pattern formation has been attributed to the dewetting of the thin film by a hydrodynamic instability. In such experiments the film is in the solid state during a substantial fraction of each thermal cycle. However, results of a linear stability analysis based on the aforementioned model suggest that solid-state mass transport has a negligible effect on morphological changes of the surface. Further, a qualitative analysis of the effect of thermoelastic stress, induced by the rapid temperature changes in the film-substrate bilayer, suggests that stress relaxation does not appreciably contribute to surface

  8. Conducting financial due diligence of medical practices.

    Science.gov (United States)

    Louiselle, P

    1995-12-01

    Many healthcare organizations are acquiring medical practices in an effort to build more integrated systems of healthcare products and services. This acquisition activity must be approached cautiously to ensure that medical practices being acquired do not have deficiencies that would jeopardize integration efforts. Conducting a thorough due diligence analysis of medical practices before finalizing the transaction can limit the acquiring organizations' legal and financial exposure and is a necessary component to the acquisition process. The author discusses the components of a successful financial due diligence analysis and addresses some of the risk factors in a practice acquisition.

  9. Characterization of Explosives Processing Waste Decomposition Due to Composting.

    Science.gov (United States)

    1994-09-01

    leachate were injected onto an Alltech RP-C 18/Anion column (150 mm x 4.6 mm ID) and were eluted at 1 mL/min using a complex ternary gradient of 0.015 M...the study because it is an agriculturally important legume; the seeds of this plant are also an important carbon sink. Thus, Glycine was advantageous

  10. Electronic Data Discovery: Integrating Due Process into Cyber Forensic Practice

    Directory of Open Access Journals (Sweden)

    John W. Bagby

    2006-03-01

    Full Text Available Most organizations and government agencies regularly become engaged in litigation with suppliers, customers, clients, employees, competitors, shareholders, prosecutors or regulatory agencies that nearly assures the need to organize, retain, find and produce business records and correspondence, e-mails, accounting records or other data relevant to disputed issues. This article discusses some high visibility cases that constrain how metadata and content is routinely made available to opposing parties in civil litigation, to prosecutors in criminal prosecutions and to agency staff in regulatory enforcement litigation. Public policy, as implemented in the rules of evidence and pretrial discovery, restrict electronic data discovery (EDD as it becomes a predominant and potentially costly pre-trial activity pivotal to modern litigation. This article discusses these constraints while identifying opportunities for the interdisciplinary activities among litigators, forensic experts and information technology professionals.

  11. Due Process in Student Discipline in Non-Public Schools.

    Science.gov (United States)

    Furst, Lyndon G.

    A study to determine the status of disciplinary procedures in nonpublic high schools in Nebraska and Kansas is described in this report. A two-part questionnaire to assess schools' written policies and actual practices was administered to 68 out of 72 private schools, a 94 percent response rate. Findings indicate that the majority of nonpublic…

  12. Disciplinary Counseling: The First Step toward Due Process.

    Science.gov (United States)

    Cunningham, Patrick J.

    1980-01-01

    The oral reprimand is seen as the most important step in a corrective discipline procedure. Steps of disciplinary counseling include: always counsel in a private place; identify the problem; identify the desired behavior; define the consequences; get commitment from employee; identify session as oral reprimand; and monitor and follow up.(MLW)

  13. Procedural Due Process for Students at Public Colleges and Universities.

    Science.gov (United States)

    Golden, Edward J.

    1982-01-01

    Reports the findings of a study to determine what procedural protections are afforded students at public colleges and universities who are faced with disciplinary or academic dismissal. The data are from 62 of the 85 public postsecondary institutions asked to provide published procedural guidelines. (Author/MLF)

  14. Statewide Responsibility and Its Effect on Due Process.

    Science.gov (United States)

    Ladd, Paula D.; Ruby, Ralph, Jr.

    1997-01-01

    Discusses the importance of being fully aware of the school district's, the state's, and the organization's rules, regulations, and laws affecting teachers, students, parents and guardians, and taxpayers regarding student organizations. (JOW)

  15. Extensive formation of sinkholes in unconsolidated rock due to underground erosive removal of sand at a marginal batter of an opencast mine - causes, process and geotechnical safety measures. Grossflaechige Erdfallbildungen im Lockergestein durch unterirdische erosive Ausraeumung von Sand and einer Tagebauendboeschung - Ursachen, Verlauf und geotechnische Sicherung

    Energy Technology Data Exchange (ETDEWEB)

    Pfeiffer, H

    1991-08-01

    When the ground water rose in the marginal batter of an opencast mine damage occurred. This was caused by the processes of internal erosion and suffusion in fine sand layers of slight thickness and by the disintegration of the overlying strata due to the formation of sinkholes. Effective safety measures involved lowering the ground-water level in the zone immediately in front of the area in question and installing an auxiliary filter unit at the marginal batter. (orig.).

  16. [Dehydration due to "mouth broken"].

    Science.gov (United States)

    Meijler, D P M; van Mossevelde, P W J; van Beek, R H T

    2012-09-01

    Two children were admitted to a medical centre due to dehydration after an oral injury and the extraction of a tooth. One child complained of "mouth broken". Dehydration is the most common water-electrolyte imbalance in children. Babies and young children are prone to dehydration due to their relatively large body surface area, the high percentage extracellular fluid, and the limited ability of the kidneys to conserve water. After the removal ofa tooth, after an oral trauma or in case of oral discomfort, a child is at greater risk of dehydration by reduced fluid and food intake due to oral pain and/or discomfort and anxiety to drink. In those cases, extra attention needs to be devoted to the intake of fluids.

  17. Autoerotic death due to electrocution

    Directory of Open Access Journals (Sweden)

    Piotr Arkuszewski

    2014-08-01

    Full Text Available Autoerotic death is a very rare case in forensic medicine. It is usually caused by asphyxia, but other reasons are also possible. Herein we present a case of autoerotic death due to electrocution caused by a self-made electrical device. The device was constructed to increase sexual feelings through stimulation of the scrotal area.

  18. Dose due to 40K

    International Nuclear Information System (INIS)

    Escareno J, E.; Vega C, H. R.

    2011-10-01

    The dose due to 40 K has been estimated. Potassium is one of the most abundant elements in nature, being approximately 2% of the Earth's crust. Potassium has three isotopes 39 K, 40 K and 41 K, two are stable while 40 K is radioactive with a half life of 1.2x10 9 years; there is 0.0117% 40 K-to-K ratio. Potassium plays an important role in plants, animals and humans growth and reproduction. Due to the fact that K is an essential element for humans, 40 K is the most abundant radioisotope in human body. In order to keep good health conditions K must be intake at daily basis trough food and beverages, however when K in ingested above the requirements produce adverse health effects in persons with renal, cardiac and hypertension problems or suffering diabetes. In 89.3% 40 K decays to 40 C through β-decay, in 10.3% decays through electronic capture and emitting 1.46 MeV γ-ray. K is abundant in soil, construction materials, sand thus γ-rays produced during 40 K decay contribute to external dose. For K in the body practically all 40 K decaying energy is absorbed by the body; thus 40 K contributes to total dose in humans and it is important to evaluate its contribution. In this work a set of 40 K sources were prepared using different amounts of KCl salt, a γ-ray spectrometer with a NaI(Tl) was characterized to standardized the sources in order to evaluate the dose due to 40 K. Using thermoluminescent dosemeters the dose due to 40 K was measured and related to the amount of 40 K γ-ray activity. (Author)

  19. Depressive disorder due to craniopharyngioma.

    Science.gov (United States)

    Spence, S A; Taylor, D G; Hirsch, S R

    1995-01-01

    Secondary causes of depression are legion, and must always be considered in patients presenting with features atypical of primary idiopathic depressive disorder. The case described is that of a middle-aged woman presenting initially with a major depressive disorder who was subsequently found to have a craniopharyngioma, leading to a revised diagnosis of mood disorder due to the tumour. Some features of the presentation might have led to earlier diagnosis had their localizing significance been recognized. Diencephalic lesions should always be considered in patients presenting with the hypersomnic-hyperphagic variant of depressive disorder. Images Figure 1 PMID:8544149

  20. Maculopathy due to drug inhalation.

    Science.gov (United States)

    Asensio-Sánchez, V M; Gonzalez-Buendia, L; Marcos-Fernández, M

    2014-08-01

    A case of maculopathy due to "poppers" is described. Poppers is a drug composed of various forms of alkyl nitrite. A 39 year-old man, who had been using poppers for years, was seen in the clinic with phosphenes, reduced visual acuity and central scotoma. The SD-OCT in the right eye showed disruption at the level of the IS/OS junction line. The SD-OCT scan in the left eye showed an outer rectangular retinal hole and an outer retinal cyst. Copyright © 2012 Sociedad Española de Oftalmología. Published by Elsevier Espana. All rights reserved.

  1. Anaphylaxis Due to Head Injury

    Directory of Open Access Journals (Sweden)

    Bruner, Heather C.

    2015-05-01

    Full Text Available Both anaphylaxis and head injury are often seen in the emergency department, but they are rarely seen in combination. We present a case of a 30-year-old woman who presented with anaphylaxis with urticaria and angioedema following a minor head injury. The patient responded well to intramuscular epinephrine without further complications or airway compromise. Prior case reports have reported angioedema from hereditary angioedema during dental procedures and maxillofacial surgery, but there have not been any cases of first-time angioedema or anaphylaxis due to head injury. [West J Emerg Med. 2015;16(3:435–437.

  2. Anaphylaxis due to head injury.

    Science.gov (United States)

    Bruner, Heather C; Bruner, David I

    2015-05-01

    Both anaphylaxis and head injury are often seen in the emergency department, but they are rarely seen in combination. We present a case of a 30-year-old woman who presented with anaphylaxis with urticaria and angioedema following a minor head injury. The patient responded well to intramuscular epinephrine without further complications or airway compromise. Prior case reports have reported angioedema from hereditary angioedema during dental procedures and maxillofacial surgery, but there have not been any cases of first-time angioedema or anaphylaxis due to head injury.

  3. Amplitude growth due to random, correlated kicks

    International Nuclear Information System (INIS)

    Michelotti, L.; Mills, F.

    1989-03-01

    Historically, stochastic processes, such as gas scattering or stochastic cooling, have been treated by the Fokker-Planck equation. In this approach, usually considered for one dimension only, the equation can be considered as a continuity equation for a variable which would be a constant of the motion in the absence of the stochastic process, for example, the action variable, I = ε/2π for betatron oscillations, where ε is the area of the Courant-Snyder ellipse, or energy in the case of unbunched beams, or the action variable for phase oscillations in case the beam is bunched. A flux, /Phi/, including diffusive terms can be defined, usually to second order. /Phi/ = M 1 F(I) + M 2 ∂F/∂I + /hor ellipsis/. M 1 and M 2 are the expectation values of δI and (δI) 2 due to the individual stochastic kicks over some period of time, long enough that the variance of these quantities is sufficiently small. Then the Fokker-Planck equation is just ∂F/∂I + ∂/Phi//∂I = 0. In many cases those where the beam distribution has already achieved its final shape, it is sufficient to find the rate of increase of by taking simple averages over the Fokker-Planck equation. At the time this work was begun, there was good knowledge of the second moment for general stochastic processes due to stochastic cooling theory, but the form of the first moment was known only for extremely wideband processes. The purposes of this note are to derive an expression relating the expected single particle amplitude growth to the noise autocorrelation function and to obtain, thereby, the form of M 1 for narrow band processes. 4 refs

  4. DYSTOCIA DUE TO SOFT TISSUE

    Science.gov (United States)

    DeCarle, Donald W.

    1954-01-01

    In dystocia caused by abnormal conditions of the soft parts, the etiologic changes may be either in the genital tissues or in adjacent soft structures. Broadly, the conditions causing the difficulty may be grouped as follows: (1) anomalies or congenital modifications; (2) tumors; (3) modifications due to age, accident or surgical operations; (4) modification of the expulsive forces; (5) abnormalities of the products of conception. Often in such circumstances cesarean section is necessary. Sometimes when tumor is present it can be removed before it interferes with delivery, but decision to excise the growth must be guided by such factors as the location of the lesion and the stage of gestation. This would determine to what extent the maintenance of pregnancy would be jeopardized by surgical intervention before term. PMID:13190430

  5. Single fatherhood due to cancer.

    Science.gov (United States)

    Yopp, Justin M; Rosenstein, Donald L

    2012-12-01

    Cancer is a leading cause of widowed fatherhood in the USA. Fathers whose spouses have died from cancer constitute a potentially vulnerable population as they adjust to their role as sole or primary caregiver while managing their own grief and that of their children. The importance of addressing the psychological needs of widowed fathers is underscored by data showing that father's coping and emotional availability are closely tied to their bereaved children's mental health. Surprisingly, scant attention has been given to the phenomenon of widowed fatherhood with virtually no clinical resources or research studies devoted to fathers who have lost their wives to cancer. This commentary highlights key challenges facing this underserved population of widowers and calls for development of research agendas and clinical interventions for single fathers due to cancer. Copyright © 2011 John Wiley & Sons, Ltd.

  6. Occupational injuries due to violence.

    Science.gov (United States)

    Hales, T; Seligman, P J; Newman, S C; Timbrook, C L

    1988-06-01

    Each year in the United States, an estimated 800 to 1,400 people are murdered at work, and an unknown number of nonfatal injuries due to workplace violence occur. Based on Ohio's workers' compensation claims from 1983 through 1985, police officers, gasoline service station employees, employees of the real estate industry, and hotel/motel employees were found to be at the highest risk for occupational violent crime (OVC) injury and death. Grocery store employees, specifically those working in convenience food stores, and employees of the real estate industry had the most reported rapes. Four previously unidentified industries at increased risk of employee victimization were described. Identification of industries and occupations at high risk for crime victimization provides the opportunity to focus preventive strategies to promote employee safety and security in the workplace.

  7. APPENDICULAR INVAGINATION DUE TO ENDOMETRIOSIS

    Directory of Open Access Journals (Sweden)

    Vasja Kruh

    2003-12-01

    Full Text Available Background. Invagination of the vermiform appendix is a very rare occurrence. We summarize epidemiologic and etiologic factors, types of classification, symtomatology, diagnostic features and treatment.Patients and treatment. The authors present 49-years old female with long-standing abdominal pains, who came in our hospital due to acute exacerbation with sever abdominal pain. Because of progressive symptoms and sensitivity in the right-lower abdominal quadrant a diagnostic laparoscopy was performed. An anomaly of cecum and the absence of appendix vermiformis have forced us to proceed with laparotomy in McBurnay point. After cecotomy an invaginated gangrenous appendix was found. The histological examination revealed endometriosis.Conclusions. By presenting this extremely rare pathology we also want to emphasize the important role of diagnostic laparoscopy in front of acute abdomen.

  8. Optical properties of palladium nanoparticles under exposure of hydrogen and inert gas prepared by dewetting synthesis of thin-sputtered layers

    Energy Technology Data Exchange (ETDEWEB)

    Kracker, Michael, E-mail: Michael.Kracker@uni-jena.de; Worsch, Christian; Ruessel, Christian [Otto-Schott-Institut, Jena University (Germany)

    2013-04-15

    Thin layers of palladium with a thickness of 5 nm were sputtered on fused silica substrates. Subsequently, the coated glasses were annealed at a temperature of 900 Degree-Sign C for 1 h. This resulted in the formation of small and well-separated palladium nanoparticles with diameters in the range from 20 to 200 nm on the glass surface. The existence of a palladium oxide layer can be detected using optical absorption spectroscopy. Purging with hydrogen leads to an irreversible change in the optical spectra due to the reduction of PdO to metallic palladium. Changing the gas atmosphere from hydrogen to argon leads to significant reversible changes in the optical properties of the particle layer. Based on Mie theory and the respective dielectric functions, the spectra were calculated using the real particle size distribution, weighted dispersions relation to adapt the geometrical conditions and complex dielectric functions of palladium and palladium hydride. A good agreement with measured spectra was found and the dependency of the surrounding media can be explained.Graphical Abstract.

  9. [Nephropathy due to Puumala hantavirus].

    Science.gov (United States)

    Dandolo, A; Prajs, N; Lizop, M

    2014-12-01

    Hemorrhagic fever with renal syndrome (HFRS) is due to an infection by the virus of the Hantavirus genus. Rodent hosts of Hantavirus are present in restricted areas in France; consequently, there are ecological niches and microepidemics of human Hantavirus infections. A HFRS case was diagnosed in the Paris region. The 11-year-old child had an acute debut fever-persistent despite antipyretic medication-asthenia, headache, abdominal pain, myalgia, thrombocytopenia, as well as renal failure with proteinuria. The diagnosis was made with a relevant clinical history and the specific serology of Puumala hantavirus. Therefore, a kidney biopsy was not necessary. What was interesting was the diagnostic approach because of the difference between the place and time of contamination and where the child became ill and developed the symptoms. The child was infected by Puumala hantavirus in Les Ardennes, a high-risk area, but became ill in the Paris region, an area with no prevalence. We review Hantavirus infections in France and its differential diagnosis. Copyright © 2014 Elsevier Masson SAS. All rights reserved.

  10. [Dwarfism due to familial panhypopituitarism].

    Science.gov (United States)

    Cos Welsh, J; Espinosa de los Monteros, A; de la Luz Ajuria, M; Morillo Almao, E

    1977-01-01

    Three sisters of 27 7/12, 13 8/12 and 9 1/12 years of age, respectively, with proportionate dwarfism, high pitched voice and lack of sexual development are described. All the patients had very low serum levels of immunoreactive growth hormone (GH), as well as of LH and FSH. Hypoglycemia induced by insulin and arginine infusion failed to increase GH levels, and the administration of the hypothalamic LH-FSH releasing hormone (LH-RH) did not elicit any response in the secretion of gonadotropins. The oldest sister developed hypothyroidism in recent years, since the I131 thyroid uptake was normal ten years before; her serum TSH was low and did not change with TRH stimulation. In addition, a low pituitary ACTH reserve was demonstrated by the hypoglycemia and metirapone tests. Case 2 showed partial pituitary TSH and ACTH reserve, whereas the youngest child only had low TSH pituitary reserve. These patients had all the clinical and laboratory characteristics of familial panhypopituitarism, with normal sella turcica. Genetic transmission in this cases is consistent with the autosomal recessive form, which is the most frequent type of inheritance of this entity. Consanguinity can not be ruled out. The results of the hypothalamic-pituitary functional tests apparently suggest that the primary defect could be located at the pituitary level. It is also possible that the pathological process may have a progressive evolution.

  11. Synthesis, fractionation, and thin film processing of nanoparticles using the tunable solvent properties of carbon dioxide gas expanded liquids

    Science.gov (United States)

    Anand, Madhu

    Nanoparticles have received significant attention because of their unusual characteristics including high surface area to volume ratios. Materials built from nanoparticles possess unique chemical, physical, mechanical and optical properties. Due to these properties, they hold potential in application areas such as catalysts, sensors, semiconductors and optics. At the same time, CO 2 in the form of supercritical fluid or CO2 gas-expanded liquid mixtures has gained significant attention in the area of processing nanostructures. This dissertation focuses on the synthesis and processing of nanoparticles using CO2 tunable solvent systems. Nanoparticle properties depend heavily on their size and, as such, the ability to finely control the size and uniformity of nanoparticles is of utmost importance. Solution based nanoparticle formation techniques are attractive due to their simplicity, but they often result in the synthesis of particles with a wide size range. To address this limitation, a post-synthesis technique has been developed in this dissertation to fractionate polydisperse nanoparticles ( s . = 30%) into monodisperse fractions ( s . = 8%) using tunable physicochemical properties of CO 2 expanded liquids, where CO2 is employed as an antisolvent. This work demonstrates that by controlling the addition of CO2 (pressurization) to an organic dispersion of nanoparticles, the ligand stabilized nanoparticles can be size selectively precipitated within a novel high pressure apparatus that confines the particle precipitation to a specified location on a surface. Unlike current techniques, this CO2 expanded liquid approach provides faster and more efficient particle size separation, reduction in organic solvent usage, and pressure tunable size selection in a single process. To improve our fundamental understanding and to further refine the size separation process, a detailed study has been performed to identify the key parameters enabling size separation of various

  12. Thin liquid films dewetting and polymer flow

    CERN Document Server

    Blossey, Ralf

    2012-01-01

    This book is a treatise on the thermodynamic and dynamic properties of thin liquid films at solid surfaces and, in particular, their rupture instabilities. For the quantitative study of these phenomena, polymer thin films haven proven to be an invaluable experimental model system.   What is it that makes thin film instabilities special and interesting, warranting a whole book? There are several answers to this. Firstly, thin polymeric films have an important range of applications, and with the increase in the number of technologies available to produce and to study them, this range is likely to expand. An understanding of their instabilities is therefore of practical relevance for the design of such films.   Secondly, thin liquid films are an interdisciplinary research topic. Interdisciplinary research is surely not an end to itself, but in this case it leads to a fairly heterogeneous community of theoretical and experimental physicists, engineers, physical chemists, mathematicians and others working on the...

  13. Asymptotic analysis of the dewetting rim

    NARCIS (Netherlands)

    Snoeijer, Jacco H.; Eggers, Jens

    2010-01-01

    Consider a film of viscous liquid covering a solid surface, which it does not wet. If there is an initial hole in the film, the film will retract further, forming a rim of fluid at the receding front. We calculate the shape of the rim as well as the speed of the front using lubrication theory. We

  14. Free surface flows: coalescence, spreading and dewetting

    NARCIS (Netherlands)

    Hernandez Sanchez, J.F.

    2015-01-01

    Capillary and wetting phenomena are an essential part of nature. Its presence is noticed in many circumstances where solid and liquid surfaces come into contact. In this thesis different types of capillary free surface flows are studied. The topics discussed are mainly the coalescence of viscous

  15. Formation of Nanoparticles by Thin Film Dewetting

    Science.gov (United States)

    Swaminathan, Parasuraman

    2009-01-01

    The synthesis and assembly of nanostructures has been extensively researched because of the potential for developing new device arrays and the myriad applications they might entail. Fundamental physical laws, however, dictate the combinations of materials/substrates that provide the requisite conditions, especially in physical vapor deposition. To…

  16. Maximum speed of dewetting on a fiber

    NARCIS (Netherlands)

    Chan, Tak Shing; Gueudre, Thomas; Snoeijer, Jacobus Hendrikus

    2011-01-01

    A solid object can be coated by a nonwetting liquid since a receding contact line cannot exceed a critical speed. We theoretically investigate this forced wetting transition for axisymmetric menisci on fibers of varying radii. First, we use a matched asymptotic expansion and derive the maximum speed

  17. Finanční due diligence

    OpenAIRE

    Slonka, Tomáš

    2015-01-01

    Thesis on financial due diligence focuses on the use of due diligence in practice. The aim of this work is to determine the risk for the investor and the calculation of the target company with and without conducting due diligence, thus finding out the added value of due diligence.

  18. The management of over closured anterior teeth due to attrition

    OpenAIRE

    Eha Djulaeha; Sukaedi Sukaedi

    2009-01-01

    Background: Tooth is the hardest tissue in human body, that can be injured because of attrition process. For old people, denture attrition process is caused by psysiological process relating with the mastication function which also supported by some bad habits such an bruxism, premature contact, and consuming habit of abrasive food. Attrition or abrasion can also be happened with patien’t dentition who does not have teeth subtutition for long time due the lost of their maxillary as well as ma...

  19. Reviewing IT in due diligence are you buying an IT asset or liability

    CERN Document Server

    Wright, Christopher

    2015-01-01

    Reviewing IT in Due Diligence provides an introduction to IRM in due diligence, and outlines some of the key IT issues to consider as part of the due diligence process. For those new to the process, it explains how to conduct an IT due diligence review, from scoping to reporting, and includes information on post-merger integration to realise business benefits from the deal. For more experienced practitioners, Reviewing IT in Due Diligence provides fresh insight into the process, highlighting issues that need to be addressed, and provides a business case for IRM involvement in the due diligenc

  20. Radiocontamination of agricultural workers due to nuclear accidents

    International Nuclear Information System (INIS)

    Petrovic, B.; Smelcerovic, M.; Djuric, G.; Popovic, D.

    1989-01-01

    In the radiocontamination of the environment due to nuclear accidents, agricultural workers should be considered as a critical group of population. The presented paper discusses this problem from the aspects of folder production. The values of the effective dose equivalent are estimated for different phases of the production process and certain procedures aimed to reduce the radiation risk are proposed (author)

  1. Numerical simulation of baseflow modification due to effects of ...

    African Journals Online (AJOL)

    Numerical simulation of baseflow modification due to effects of sediment yield. ... Physically-based mathematical modelling affords the opportunity to look at this kind of interaction, which should be simulated by deterministic responses of both water and fluvial processes. In addition to simulating the streamflow and ...

  2. Radiocontamination of agricultural workers due to nuclear accidents

    Energy Technology Data Exchange (ETDEWEB)

    Petrovic, B [Faculty of Veterinary Medicine, Beograd, (Serbia and Montenegro); Smelcerovic, M; Djuric, G; Popovic, D [Institute of Nuclear Sciences Boris Kidric, Vinca, Beograd (Serbia and Montenegro)

    1989-07-01

    In the radiocontamination of the environment due to nuclear accidents, agricultural workers should be considered as a critical group of population. The presented paper discusses this problem from the aspects of folder production. The values of the effective dose equivalent are estimated for different phases of the production process and certain procedures aimed to reduce the radiation risk are proposed (author)

  3. Peritoneal tuberculosis due to Mycobacterium caprae

    Directory of Open Access Journals (Sweden)

    T. Nebreda

    2016-01-01

    Full Text Available The incidence of tuberculosis in humans due to Mycobacterium caprae is very low and is almost confined to Europe. We report a case of a previously healthy 41-year-old Moroccan with a 6 month history of abdominal pain, weight loss, fatigue and diarrhea. A diagnosis of peritoneal tuberculosis due to M. caprae was made.

  4. Turbulent momentum transport due to neoclassical flows

    International Nuclear Information System (INIS)

    Lee, Jungpyo; Barnes, Michael; Parra, Felix I; Belli, Emily; Candy, Jeff

    2015-01-01

    Intrinsic toroidal rotation in a tokamak can be driven by turbulent momentum transport due to neoclassical flow effects breaking a symmetry of turbulence. In this paper we categorize the contributions due to neoclassical effects to the turbulent momentum transport, and evaluate each contribution using gyrokinetic simulations. We find that the relative importance of each contribution changes with collisionality. For low collisionality, the dominant contributions come from neoclassical particle and parallel flows. For moderate collisionality, there are non-negligible contributions due to neoclassical poloidal electric field and poloidal gradients of density and temperature, which are not important for low collisionality. (paper)

  5. Study on the import dues system

    Energy Technology Data Exchange (ETDEWEB)

    Woo, Sung Keun [LG-Caltex Oil Co., Seoul (Korea)

    2000-04-01

    Since October 1979, Korea had implemented a petroleum project fund dues system to actively prepare for unstable international petroleum condition. However, as the size of operating a petroleum project fund was bigger and the influence of government on this fund became powerful, it was inserted in the government tax revenues as a {sup S}pecial account for energy and resource project{sup i}n March 1994 and its name was changed to import dues. In this study, it discusses the facts of import dues system, which exists only in Korea, and its policy directions since this system has been reviewed due to the economic development, liberalization of petroleum industry and inequity between alternative energy sources. 4 tabs.

  6. Occurrence of pneumomediastinum due to dental procedures.

    Science.gov (United States)

    Aslaner, Mehmet Ali; Kasap, Gül Nihal; Demir, Cihat; Akkaş, Meltem; Aksu, Nalan M

    2015-01-01

    The occurrence of pneumomediastinum and massive subcutaneous emphysema due to dental procedures is quite rare. We present a case of pneumomediastinum and massive subcutaneous emphysema that occurred during third molar tooth extraction with air-turbine handpiece.

  7. Greenhouse effect due to atmospheric nitrous oxide

    Science.gov (United States)

    Yung, Y. L.; Wang, W. C.; Lacis, A. A.

    1976-01-01

    The greenhouse effect due to nitrous oxide in the present atmosphere is about 0.8 K. Increase in atmospheric N2O due to perturbation of the nitrogen cycle by man may lead to an increase in surface temperature as large as 0.5 K by 2025, or 1.0 K by 2100. Other climatic effects of N2O are briefly discussed.

  8. Due diligence duties for an environmental liability

    International Nuclear Information System (INIS)

    Huebsch, M.

    2000-04-01

    Jurisdiction turned out well to create a basic ruling for due diligence duties. These due diligence duties are high standards for the law of torts (outside of contracts) within the Austrian civil law and represent a liability-extension for the holder of the source of danger. They establish an action for injunction in particular for preventing (further) damages. Therewith due diligence duties get a general sense in the range of a civil law for environmental liability. The responsible holder of a danger zone will therefore influence his way of acting to protect potential victims and the environment. The burden of proof is on the plaintiff (victims) under the Civil Code. Victims have specific sources of danger including high endangering special facilities in their argumentation with the so-called prima-facie-proof or first-appearance-proof. A turning back of the presentation of evidence to the polluter is wrong. The polluter himself has a continuing liability for dangerous activities and his clerks in the case of an extremely high danger of damage. All due diligence duties can be arranged in three areas: in information-, danger-avoidance- and danger-prevention-duties. The determination of range and essence of the duties has to be adjusted to each individual case. The range of the specific danger area is the essential link. The intensity of due diligence duties is increasing with the size of danger in the way of a movable system depending on the protected interest. Due diligence duties have to be kept within reasonable limits with two criterions: necessarity and demand. Proportionality of actions is a third criterion to avoid exaggeration of due diligence duties to obtain an effective protection for victims including the environment. (author)

  9. Plasma diffusion due to magnetic field fluctuations

    International Nuclear Information System (INIS)

    Okuda, H.; Lee, W.W.; Lin, A.T.

    1979-01-01

    Plasma diffusion due to magnetic field fluctuations has been studied in two dimensions for a plasma near thermal equilibrium and when the fluctuations are suprathermal. It is found that near thermal equilibrium electron diffusion varies as B -2 when the collisionless skin depth is greater than the thermal electron gyroradius and is generally smaller than the diffusion due to collisions or electrostatic fluctuations for a low-β plasma. When the suprathermal magnetic fluctuation exists because of macroscopic plasma currents, electron diffusion is enhanced due to the coalescence of current filaments and magnetic islands. Magnetic field energy is found to condense to the longest wavelength available in the system and stays there longer than the electron diffusion time scale

  10. Paraneoplastic Cushing Syndrome Due To Wilm's Tumor.

    Science.gov (United States)

    Faizan, Mahwish; Manzoor, Jaida; Saleem, Muhammad; Anwar, Saadia; Mehmood, Qaiser; Hameed, Ambreen; Ali, Agha Shabbir

    2017-05-01

    Paraneoplastic syndromes are rare disorders that are triggered by an altered immune system response to neoplasm. Paraneoplastic syndromes may be the first or the most prominent manifestations of cancer. Wilm's tumor is the most frequent pediatric renal malignancy and usually presents with abdominal mass. Unusual presentations like acquired von Willebrand disease, sudden death due to pulmonary embolism and Cushing syndrome have been described in the literature. Cushing syndrome, as the presenting symptom of a malignant renal tumor in children, is a very rare entity. Few case reports are available in the literature exploring the option of preoperative chemotherapy as well as upfront nephrectomy. We report a rare case of paraneoplastic Cushing syndrome due to a Wilm's tumor. Based on gradual decrease of postoperative weight, blood pressure, serum adrenocorticotropic hormone, and plasma cortisol levels, along with histological confirmation of Wilm's tumor, paraneoplastic Cushing syndrome due to Wilm's tumor was confirmed.

  11. Paraneoplastic cushing syndrome due to wilm's tumor

    International Nuclear Information System (INIS)

    Faizan, M.; Anwar, S.; Hameed, A.; Manzoor, J.; Saleem, M.; Mehmood, Q.; Ali, A. S.

    2017-01-01

    Paraneoplastic syndromes are rare disorders that are triggered by an altered immune system response to neoplasm. Paraneoplastic syndromes may be the first or the most prominent manifestations of cancer. Wilm's tumor is the most frequent pediatric renal malignancy and usually presents with abdominal mass. Unusual presentations like acquired von Willebrand disease, sudden death due to pulmonary embolism and Cushing syndrome have been described in the literature. Cushing syndrome, as the presenting symptom of a malignant renal tumor in children, is a very rare entity. Few case reports are available in the literature exploring the option of preoperative chemotherapy as well as upfront nephrectomy. We report a rare case of paraneoplastic Cushing syndrome due to a Wilm's tumor. Based on gradual decrease of postoperative weight, blood pressure, serum adrenocorticotropic hormone, and plasma cortisol levels, alongwith histological confirmation of Wilm's tumor, paraneoplastic Cushing syndrome due to Wilm's tumor was confirmed. (author)

  12. A canned food scheduling problem with batch due date

    Science.gov (United States)

    Chung, Tsui-Ping; Liao, Ching-Jong; Smith, Milton

    2014-09-01

    This article considers a canned food scheduling problem where jobs are grouped into several batches. Jobs can be sent to the next operation only when all the jobs in the same batch have finished their processing, i.e. jobs in a batch, have a common due date. This batch due date problem is quite common in canned food factories, but there is no efficient heuristic to solve the problem. The problem can be formulated as an identical parallel machine problem with batch due date to minimize the total tardiness. Since the problem is NP hard, two heuristics are proposed to find the near-optimal solution. Computational results comparing the effectiveness and efficiency of the two proposed heuristics with an existing heuristic are reported and discussed.

  13. Environmental impact due to nuclear power plants

    International Nuclear Information System (INIS)

    Kellermann, O.; Balfanz, H.P.

    1975-01-01

    The environmental impact due to nuclear power plants is smaller than that due to fossil-fired power plants. The risks of the nuclear power plant operation are determined by the quantity and the probability of the release of radioactive materials. According to the value, the risks of normal operation can be compared to the accident risks. An attempt should be made to effectively reduce the remaining risk at unfavourable sites with the emphasis on accidents with larger effects than design basis accidents. (orig./LH) [de

  14. Weibel instability due to inverse bremsstrahlung absorption

    International Nuclear Information System (INIS)

    Bendib, A.; Bendib, K.; Bendib, A.; Bendib, K.; Sid, A.; Bendib, K.

    1997-01-01

    A new Weibel source due to the inverse bremsstrahlung absorption is presented. It has been shown that in homogeneous plasmas, this mechanism may drive strong collisionless Weibel modes with growth rates of order of γ∼10 11 s -1 and negligible group velocities. In the laser-produced plasmas, for short laser wavelengths (λ L 10 14 W/cm 2 ), this Weibel source is most efficient as the ones due to the heat flux and the plasma expansion. The useful scaling law of the convective e-foldings, with respect to the laser and the plasma parameters, is also derived. copyright 1997 The American Physical Society

  15. Cracking in reinforced concrete structures due to imposed deformations

    Energy Technology Data Exchange (ETDEWEB)

    Nagy, A.

    1997-04-01

    This thesis is concerned with modeling of the cracking process in reinforced concrete due to imposed deformations. Cracking is investigated both at early ages, during hydration, and at mature age when the final properties of the concrete are reached. One of the most important material characteristics of the concrete at early ages, the Young`s modulus is determined by means of a dynamic method called the resonance frequency method. 40 refs

  16. Breast abscess due to Actinomyces europaeus.

    Science.gov (United States)

    Silva, W A; Pinheiro, A M; Jahns, B; Bögli-Stuber, K; Droz, S; Zimmerli, S

    2011-06-01

    Actinomyces europaeus was first described in 1997 as a new species causing predominantly skin and soft-tissue infections. Mastitis due to A. europaeus is an unusual condition. This article reports a case of primary breast abscess caused by A. europaeus in a postmenopausal woman.

  17. Freezing of Water Droplet due to Evaporation

    Science.gov (United States)

    Satoh, Isao; Fushinobu, Kazuyoshi; Hashimoto, Yu

    In this study, the feasibility of cooling/freezing of phase change.. materials(PCMs) due to evaporation for cold storage systems was experimentally examined. A pure water was used as the test PCM, since the latent heat due to evaporation of water is about 7 times larger than that due to freezing. A water droplet, the diameter of which was 1-4 mm, was suspended in a test cell by a fine metal wire (O. D.= 100μm),and the cell was suddenly evacuated up to the pressure lower than the triple-point pressure of water, so as to enhance the evaporation from the water surface. Temperature of the droplet was measured by a thermocouple, and the cooling/freezing behavior and the temperature profile of the droplet surface were captured by using a video camera and an IR thermo-camera, respectively. The obtained results showed that the water droplet in the evacuated cell is effectively cooled by the evaporation of water itself, and is frozen within a few seconds through remarkable supercooling state. When the initial temperature of the droplet is slightly higher than the room temperature, boiling phenomena occur in the droplet simultaneously with the freezing due to evaporation. Under such conditions, it was shown that the degree of supercooling of the droplet is reduced by the bubbles generated in the droplet.

  18. Six questions about translational due diligence.

    Science.gov (United States)

    Selinger, Evan

    2010-04-28

    To maintain stable respect and support, translational research must be guided by appropriate ethical, social, legal, and political concerns and carry out culturally competent practices. Considering six key questions concerning due diligence will enable the translational research community to examine critically how it approaches these endeavors.

  19. Facial nerve palsy due to birth trauma

    Science.gov (United States)

    Seventh cranial nerve palsy due to birth trauma; Facial palsy - birth trauma; Facial palsy - neonate; Facial palsy - infant ... An infant's facial nerve is also called the seventh cranial nerve. It can be damaged just before or at the time of delivery. ...

  20. [Severe, subacute axonal polyneuropathy due to hypophosphatemia].

    NARCIS (Netherlands)

    Eijk, J.J.J. van; Abdo, W.F.; Deurwaarder, E. den; Zwarts, M.J.; Warrenburg, B.P.C. van de

    2010-01-01

    A 46-year-old man receiving tube feeding because of anorexia and weight loss developed progressive neurological symptoms initially resembling Guillain-Barre syndrome. Eventually axonal neuropathy due to severe hypophosphatemia was diagnosed. Hypophosphatemia can be caused by the so-called refeeding