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Sample records for surface activation process

  1. Carbon activation process for increased surface accessibility in electrochemical capacitors

    Science.gov (United States)

    Doughty, Daniel H.; Eisenmann, Erhard T.

    2001-01-01

    A process for making carbon film or powder suitable for double capacitor electrodes having a capacitance of up to about 300 F/cm.sup.3 is disclosed. This is accomplished by treating in aqueous nitric acid for a period of about 5 to 15 minutes thin carbon films obtained by carbonizing carbon-containing polymeric material having a high degree of molecular directionality, such as polyimide film, then heating the treated carbon film in a non-oxidizing atmosphere at a non-graphitizing temperature of at least 350.degree. C. for about 20 minutes, and repeating alternately the nitric acid step and the heating step from 7 to 10 times. Capacitors made with this carbon may find uses ranging from electronic devices to electric vehicle applications.

  2. Processing method and processing device for liquid waste containing surface active agent and radioactive material

    International Nuclear Information System (INIS)

    Nishi, Takashi; Matsuda, Masami; Baba, Tsutomu; Yoshikawa, Ryozo; Yukita, Atsushi.

    1998-01-01

    Washing liquid wastes containing surface active agents and radioactive materials are sent to a deaerating vessel. Ozone is blown into the deaerating vessel. The washing liquid wastes dissolved with ozone are introduced to a UV ray irradiation vessel. UV rays are irradiated to the washing liquid wastes, and hydroxy radicals generated by photodecomposition of dissolved ozone oxidatively decompose surface active agents contained in the washing liquid wastes. The washing liquid wastes discharged from the UV ray irradiation vessel are sent to an activated carbon mixing vessel and mixed with powdery activated carbon. The surface active agents not decomposed in the UV ray irradiation vessel are adsorbed to the activated carbon. Then, the activated carbon and washing liquid wastes are separated by an activated carbon separating/drying device. Radioactive materials (iron oxide and the like) contained in the washing liquid wastes are mostly granular, and they are separated and removed from the washing liquid wastes in the activated carbon separating/drying device. (I.N.)

  3. Study of the processes of adsorption of amine-containing surface-active substance on the surface of Aluminum powder

    Directory of Open Access Journals (Sweden)

    Antonina Dyuryagina

    2012-03-01

    Full Text Available Equilibrium characteristics of adsorption on a surface of a pigment depending on concentration factors and temperature of the dispersive environment are defined. Kinetic laws of superficial activity of binary, threefold homogeneous and heterogeneous modeling systems are studied. The estimation of mechanisms of process of adsorption is carried out.

  4. Mechanics of active surfaces

    Science.gov (United States)

    Salbreux, Guillaume; Jülicher, Frank

    2017-09-01

    We derive a fully covariant theory of the mechanics of active surfaces. This theory provides a framework for the study of active biological or chemical processes at surfaces, such as the cell cortex, the mechanics of epithelial tissues, or reconstituted active systems on surfaces. We introduce forces and torques acting on a surface, and derive the associated force balance conditions. We show that surfaces with in-plane rotational symmetry can have broken up-down, chiral, or planar-chiral symmetry. We discuss the rate of entropy production in the surface and write linear constitutive relations that satisfy the Onsager relations. We show that the bending modulus, the spontaneous curvature, and the surface tension of a passive surface are renormalized by active terms. Finally, we identify active terms which are not found in a passive theory and discuss examples of shape instabilities that are related to active processes in the surface.

  5. A thermal spike analysis of low energy ion activated surface processes

    International Nuclear Information System (INIS)

    Gilmore, G.M.; Haeri, A.; Sprague, J.A.

    1989-01-01

    This paper reports a thermal spike analysis utilized to predict the time evolution of energy propagation through a solid resulting from energetic particle impact. An analytical solution was developed that can predict the number of surface excitations such as desorption, diffusion or chemical reaction activated by an energetic particle. The analytical solution is limited to substrates at zero Kelvin and to materials with constant thermal diffusivities. These limitations were removed by developing a computer numerical integration of the propagation of the thermal spike through the solid and the subsequent activation of surface processes

  6. Surface characterization of activated chalcopyrite particles via the FLSmidth ROL process. Part 1: Electron microscope investigations

    DEFF Research Database (Denmark)

    Karcz, Adam Paul; Damø, Anne Juul; Illerup, Jytte Boll

    Because of its unique semiconductor properties, the world’s most abundant copper mineral (chalcopyrite) is refractory with respect to atmospheric leaching using traditional ferric sulfate lixiviants. A novel approach to address this issue – conducted at FLSmidth – utilizes a mechanochemical Rapid...... of copper(II) to dope the semiconductor lattice and thereby "activate" the chalcopyrite, thereby reducing leach times below 2 hours (>98% recovery). Because the activation plays a major role in accelerating the leaching step, it is critical to understand the nature of this intermediate and its part...... in the ROL process. The current work presents results from electron microscope investigations of surface-activated particles....

  7. Effect of plasma-induced surface charging on catalytic processes: application to CO2 activation

    Science.gov (United States)

    Bal, Kristof M.; Huygh, Stijn; Bogaerts, Annemie; Neyts, Erik C.

    2018-02-01

    Understanding the nature and effect of the multitude of plasma-surface interactions in plasma catalysis is a crucial requirement for further process development and improvement. A particularly intriguing and rather unique property of a plasma-catalytic setup is the ability of the plasma to modify the electronic structure, and hence chemical properties, of the catalyst through charging, i.e. the absorption of excess electrons. In this work, we develop a quantum chemical model based on density functional theory to study excess negative surface charges in a heterogeneous catalyst exposed to a plasma. This method is specifically applied to investigate plasma-catalytic CO2 activation on supported M/Al2O3 (M = Ti, Ni, Cu) single atom catalysts. We find that (1) the presence of a negative surface charge dramatically improves the reductive power of the catalyst, strongly promoting the splitting of CO2 to CO and oxygen, and (2) the relative activity of the investigated transition metals is also changed upon charging, suggesting that controlled surface charging is a powerful additional parameter to tune catalyst activity and selectivity. These results strongly point to plasma-induced surface charging of the catalyst as an important factor contributing to the plasma-catalyst synergistic effects frequently reported for plasma catalysis.

  8. Activity of processes on the visible surface of planets of Solar system

    Science.gov (United States)

    Vidmachenko, A. P.

    2016-05-01

    According to modern concepts bodies of the solar system formed from a single cloud of gas and dust. Calculations show that in the protoplanetary nebula where the temperature is lowered to 1600 K - appeared the first type of metal (aluminum and titanium) and metal oxides in the form of dust particles. With further decreasing temperature of the nebula to 1400 K - appeared also dust of iron and iron-nikel alloy; at 1300 K - appear solid silicates; magnesium minerals formed at T 1200 K. These components are material for the formation of basaltic rocks. At temperatures T 300 K begins to form water molecules. At 100-200 K in a remote part of the nebula - ammonia, methane and their ice are formed. In the outer part of Solar system this ices are now preserved in comet nuclei and in the icy satellites of giant planets. During T 400 million years after the formation of the Sun, at first - from dust component of the protoplanetary cloud was formed many intermediate bodies with the size of hundreds kilometers. Their gravitational interaction was reinforced in process of their grow. The bodies, which were growing fastest, they became the embryos of the future planets. All bodies of the solar system in different degrees show manifestations of different types of activity processes on the surface or at the level of the visible clouds. This activity depends on the distance of a particular body from the Sun, surface chemical composition, physical conditions at the surface and so on. The farther away from the Sun is the object, the temperature of its visible surface is lower, and by that more interesting is the set of processes, of chemical and physical transformations that there is possible to register. The surface of each planets of Solar system is very active in a variety of set temperature and chemical composition

  9. Ultrahigh surface area carbon from carbonated beverages: Combining self-templating process and in situ activation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Pengfei; Zhang, Zhiyong; Chen, Jihua; Dai, Sheng

    2015-11-01

    Ultrahigh surface area carbons (USACs, e.g., >2000 m2/g) are attracting tremendous attention due to their outstanding performance in energy-related applications. The state-of-art approaches to USACs involve templating or activation methods and all these techniques show certain drawbacks. In this work, a series of USACs with specific surface areas up to 3633 m2/g were prepared in two steps: hydrothermal carbonization (200 °C) of carbonated beverages (CBs) and further thermal treatment in nitrogen (600–1000 °C). The rich inner porosity is formed by a self-templated process during which acids and polyelectrolyte sodium salts in the beverage formulas make some contribution. This strategy covers various CBs such as Coca Cola®, Pepsi Cola®, Dr. Pepper®, and Fanta® and it enables an acceptable product yield (based on sugars), for example: 21 wt% for carbon (2940 m2/g) from Coca Cola®. Being potential electrode materials for supercapacitors, those carbon materials possessed a good specific capacitance (57.2–185.7 F g-1) even at a scan rate of 1000 mV s-1. Thus, a simple and efficient strategy to USACs has been presented.

  10. Evaluation of Antibacterial Activity of Titanium Surface Modified by PVD/PACVD Process.

    Science.gov (United States)

    Ji, Min-Kyung; Lee, Min-Joo; Park, Sang-Won; Lee, Kwangmin; Yun, Kwi-Dug; Kim, Hyun-Seung; Oh, Gye-Jeong; Kim, Ji-Hyun; Lim, Hyun-Pil

    2016-02-01

    The aim of this study was to evaluate the response of Streptococcus mutans (S. mutans) via crystal violet staining assay on titanium surface modified by physical vapor deposition/plasma assisted chemical vapor deposition process. Specimens were divided into the following three groups: polished titanium (control group), titanium modified by DC magnetron sputtering (group TiN-Ti), and titanium modified by plasma nitriding (group N-Ti). Surface characteristics of specimens were observed by using nanosurface 3D optical profiler and field emission scanning electron microscope. Group TiN-Ti showed TiN layer of 1.2 microm in thickness. Group N-Ti was identified as plasma nitriding with X-ray photoelectron spectroscopy. Roughness average (Ra) of all specimens had values 0.05). Within the process condition of this study, modified titanium surfaces by DC magnetron sputtering and plasma nitriding did not influence the adhesion of S. mutans.

  11. Actively stabilized optical fiber interferometry technique for online/in-process surface measurement

    International Nuclear Information System (INIS)

    Wang Kaiwei; Martin, Haydn; Jiang Xiangqian

    2008-01-01

    In this paper, we report the recent progress in optical-beam scanning fiber interferometry for potential online nanoscale surface measurement based on the previous research. It attempts to generate a robust and miniature measurement device for future development into a multiprobe array measurement system. In this research, both fiber-optic-interferometry and the wavelength-division-multiplexing techniques have been used, so that the optical probe and the optical interferometer are well spaced and fast surface scanning can be carried out, allowing flexibility for online measurement. In addition, this system provides a self-reference signal to stabilize the optical detection with high common-mode noise suppression by adopting an active phase tracking and stabilization technique. Low-frequency noise was significantly reduced compared with unstabilized result. The measurement of a sample surface shows an attained repeatability of 3.3 nm

  12. A STUDY ON THE PROPERTIES OF SURFACEACTIVE FLUIDS USED IN BURNISHING AND SHOT PEENING PROCESSES

    OpenAIRE

    Kazmierz Zaleski

    2016-01-01

    A method is presented for the study of surface-active properties of a fluids, in burnishing and shot peening processes used, which consists in comparing mean plastic strains of thin metal foil subjected to tensile tests in the examined fluid and in air. As a surface-active additive to the fluid (mineral oil), methyl polymethacrylate solution was used. It was found that the surfactant activity coefficient depended on the type of examined fluid as well as on the thickness of the foil being stre...

  13. A STUDY ON THE PROPERTIES OF SURFACEACTIVE FLUIDS USED IN BURNISHING AND SHOT PEENING PROCESSES

    Directory of Open Access Journals (Sweden)

    Kazmierz Zaleski

    2016-09-01

    Full Text Available A method is presented for the study of surface-active properties of a fluids, in burnishing and shot peening processes used, which consists in comparing mean plastic strains of thin metal foil subjected to tensile tests in the examined fluid and in air. As a surface-active additive to the fluid (mineral oil, methyl polymethacrylate solution was used. It was found that the surfactant activity coefficient depended on the type of examined fluid as well as on the thickness of the foil being stretched. Results of analyses of the surface-active properties of a fluid can be compared only when metal foils of equal thickness made from one specific material are used. It can be supposed that the introduction of methyl polymethacrylate solution as an additive to the metalworking fluid will have a beneficial effect on the course and the results of burnishing and shot peening of metals.

  14. Spent coffee-based activated carbon: specific surface features and their importance for H2S separation process.

    Science.gov (United States)

    Kante, Karifala; Nieto-Delgado, Cesar; Rangel-Mendez, J Rene; Bandosz, Teresa J

    2012-01-30

    Activated carbons were prepared from spent ground coffee. Zinc chloride was used as an activation agent. The obtained materials were used as a media for separation of hydrogen sulfide from air at ambient conditions. The materials were characterized using adsorption of nitrogen, elemental analysis, SEM, FTIR, and thermal analysis. Surface features of the carbons depend on the amount of an activation agent used. Even though the residual inorganic matter takes part in the H(2)S retention via salt formation, the porous surface of carbons governs the separation process. The chemical activation method chosen resulted in formation of large volume of pores with sizes between 10 and 30Å, optimal for water and hydrogen sulfide adsorption. Even though the activation process can be optimized/changed, the presence of nitrogen in the precursor (caffeine) is a significant asset of that specific organic waste. Nitrogen functional groups play a catalytic role in hydrogen sulfide oxidation. Copyright © 2011 Elsevier B.V. All rights reserved.

  15. Surface Activity of Sulfactin Recovered and Purified from Fermentation Broth Using a Two-Step Ultrafiltration (UF) Process

    International Nuclear Information System (INIS)

    Mohd Hafez Mohd Isa; Frazier, A.R.; Jauregi, P.

    2011-01-01

    B. subtilis under certain types of media and fermentation conditions can produce surfactant, a bio surfactant which belongs to the lipo peptide class. Surfactant has exceptional surfactant activity, and exhibits some interesting biological characteristics such as antibacterial activity, anti tumoral activity against ascites carcinoma cells, and a hypercholesterolaemia activity that inhibits cAMP phosphodiesterase, as well as having anti-HIV properties. A cost effective recovery and purification of surfactant from fermentation broth using a two-step ultrafiltration (UF) process has been developed in order to reduce the cost of surfactant production. In this study, competitive adsorption of surfactant and proteins at the air-water interface was studied using surface pressure measurements. Small volumes of bovine serum albumin (BSA) and β-casein solutions were added to the air-water interface on a Langmuir trough and allowed to stabilise before the addition of surfactant to the sub phase. Contrasting interfacial behaviour of proteins was observed with β-casein showing faster initial adsorption compared to BSA. On introduction of surfactant both proteins were displaced but a longer time were taken to displace β-casein. Overall the results showed surfactant were highly surface-active by forming a β-sheet structure at the air-water interface after reaching its critical micelle concentration (CMC) and were effective in removing both protein films, which can be explained following the orogenic mechanism. Results showed that the two-step UF process was effective to achieve high purity and fully functional surfactant. (author)

  16. Application of electrochemical peroxidation (ECP) process for waste-activated sludge stabilization and system optimization using response surface methodology (RSM).

    Science.gov (United States)

    Gholikandi, Gagik Badalians; Kazemirad, Khashayar

    2018-03-01

    In this study, the performance of the electrochemical peroxidation (ECP) process for removing the volatile suspended solids (VSS) content of waste-activated sludge was evaluated. The Fe 2+ ions required by the process were obtained directly from iron electrodes in the system. The performance of the ECP process was investigated in various operational conditions employing a laboratory-scale pilot setup and optimized by response surface methodology (RSM). According to the results, the ECP process showed its best performance when the pH value, current density, H 2 O 2 concentration and the retention time were 3, 3.2 mA/cm 2 , 1,535 mg/L and 240 min, respectively. In these conditions, the introduced Fe 2+ concentration was approximately 500 (mg/L) and the VSS removal efficiency about 74%. Moreover, the results of the microbial characteristics of the raw and the stabilized sludge demonstrated that the ECP process is able to remove close to 99.9% of the coliforms in the raw sludge during the stabilization process. The energy consumption evaluation showed that the required energy of the ECP reactor (about 1.8-2.5 kWh (kg VSS removed) -1 ) is considerably lower than for aerobic digestion, the conventional waste-activated sludge stabilization method (about 2-3 kWh (kg VSS removed) -1 ). The RSM optimization process showed that the best operational conditions of the ECP process comply with the experimental results, and the actual and the predicted results are in good conformity with each other. This feature makes it possible to predict the introduced Fe 2+ concentrations into the system and the VSS removal efficiency of the process precisely.

  17. STUDY OF DESTRUCTION PROCESSES OF SYNTHETIC SURFACE-ACTIVE SUBSTENCES (SURFFACTANTS IN BARRIER DISCHARGE

    Directory of Open Access Journals (Sweden)

    V.I. Grinevich

    2012-06-01

    Full Text Available Kinetic data of degradation on aqueous solutions of surfactants in the plasma of barrier discharge are presented. The possible mechanism of proceeding processes is offered and considered. It is shown that the treatment in a barrier discharge results in decomposition efficiency of 95%. It is established that the main product of degradation are carboxylic acids.

  18. Estimates of late Cenozoic climate change relevant to Earth surface processes in tectonically active orogens

    Science.gov (United States)

    Mutz, Sebastian G.; Ehlers, Todd A.; Werner, Martin; Lohmann, Gerrit; Stepanek, Christian; Li, Jingmin

    2018-04-01

    The denudation history of active orogens is often interpreted in the context of modern climate gradients. Here we address the validity of this approach and ask what are the spatial and temporal variations in palaeoclimate for a latitudinally diverse range of active orogens? We do this using high-resolution (T159, ca. 80 × 80 km at the Equator) palaeoclimate simulations from the ECHAM5 global atmospheric general circulation model and a statistical cluster analysis of climate over different orogens (Andes, Himalayas, SE Alaska, Pacific NW USA). Time periods and boundary conditions considered include the Pliocene (PLIO, ˜ 3 Ma), the Last Glacial Maximum (LGM, ˜ 21 ka), mid-Holocene (MH, ˜ 6 ka), and pre-industrial (PI, reference year 1850). The regional simulated climates of each orogen are described by means of cluster analyses based on the variability in precipitation, 2 m air temperature, the intra-annual amplitude of these values, and monsoonal wind speeds where appropriate. Results indicate the largest differences in the PI climate existed for the LGM and PLIO climates in the form of widespread cooling and reduced precipitation in the LGM and warming and enhanced precipitation during the PLIO. The LGM climate shows the largest deviation in annual precipitation from the PI climate and shows enhanced precipitation in the temperate Andes and coastal regions for both SE Alaska and the US Pacific Northwest. Furthermore, LGM precipitation is reduced in the western Himalayas and enhanced in the eastern Himalayas, resulting in a shift of the wettest regional climates eastward along the orogen. The cluster-analysis results also suggest more climatic variability across latitudes east of the Andes in the PLIO climate than in other time slice experiments conducted here. Taken together, these results highlight significant changes in late Cenozoic regional climatology over the last ˜ 3 Myr. Comparison of simulated climate with proxy-based reconstructions for the MH and

  19. An automated processing chains for surface temperature monitoring on Earth's most active volcanoes by optical data from multiple satellites

    Science.gov (United States)

    Silvestri, Malvina; Musacchio, Massimo; Fabrizia Buongiorno, Maria

    2017-04-01

    The Geohazards Exploitation Platform, or GEP is one of six Thematic Exploitation Platforms developed by ESA to serve data user communities. As a new element of the ground segment delivering satellite results to users, these cloud-based platforms provide an online environment to access information, processing tools, computing resources for community collaboration. The aim is to enable the easy extraction of valuable knowledge from vast quantities of satellite-sensed data now being produced by Europe's Copernicus programme and other Earth observation satellites. In this context, the estimation of surface temperature on active volcanoes around the world is considered. E2E processing chains have been developed for different satellite data (ASTER, Landsat8 and Sentinel 3 missions) using thermal infrared (TIR) channels by applying specific algorithms. These chains have been implemented on the GEP platform enabling the use of EO missions and the generation of added value product such as surface temperature map, from not skilled users. This solution will enhance the use of satellite data and improve the dissemination of the results saving valuable time (no manual browsing, downloading or processing is needed) and producing time series data that can be speedily extracted from a single co-registered pixel, to highlight gradual trends within a narrow area. Moreover, thanks to the high-resolution optical imagery of Sentinel 2 (MSI), the detection of lava maps during an eruption can be automatically obtained. The proposed lava detection method is based on a contextual algorithm applied to Sentinel-2 NIR (band 8 - 0.8 micron) and SWIR (band 12 - 2.25 micron) data. Examples derived by last eruptions on active volcanoes are showed.

  20. Influence of the water molecules near surface of viral protein on virus activation process

    Energy Technology Data Exchange (ETDEWEB)

    O, Shepelenko S; S, Salnikov A; V, Rak S; P, Goncharova E; B, Ryzhikov A, E-mail: shep@vector.nsc.r, E-mail: shep@ngs.r [Federal State Research Institution State Research Center of Virology and Biotechnology VECTOR of the Federal Service for Surveillance in Consumer Rights Protection and Human Well-being (FSRI SRC VB VECTOR) Koltsovo, Novosibirsk Region (Russian Federation)

    2009-06-01

    The infection of a cell with influenza virus comprises the stages of receptor binding to the cell membrane, endocytosis of virus particle, and fusion of the virus envelope and cell endosome membrane, which is determined by the conformational changes in hemagglutinin, a virus envelope protein, caused by pH decrease within the endosome. The pH value that induces conformation rearrangements of hemagglutinin molecule considerably varies for different influenza virus strains, first and foremost, due to the differences in amino acid structure of the corresponding proteins. The main goal of this study was to construct a model making it possible to assess the critical pH value characterizing the fusogenic activity of influenza virus hemagglutinin from the data on hemagglutinin structure and experimental verification of this model. Under this model, we assume that when the electrostatic force between interacting hemagglutinin molecules in the virus envelop exceeds a certain value, the hemagglutinin HA1 subunits are arranged so that they form a cavity sufficient for penetration of water molecules. This event leads to an irreversible hydration of the inner fragments of hemagglutinin molecule in a trimer and to the completion of conformational changes. The geometry of electrostatic field in hemagglutinin trimer was calculated taking into account the polarization effects near the interface of two dielectrics, aqueous medium and protein macromolecule. The critical pH values for the conformational changes in hemagglutinin were measured by the erythrocyte hemolysis induced by influenza virus particles when decreasing pH. The critical pH value conditionally separating the pH range into the regions with and without the conformational changes was calculated for several influenza virus H1N1 and H3N2 strains based on the data on the amino acid structure of the corresponding hemagglutinin molecules. Comparison of the theoretical and experimental values of critical pH values for

  1. Rubber friction and force transmission during the shearing process of actively-driven vacuum grippers on rough surfaces

    International Nuclear Information System (INIS)

    Kern, Patrick

    2016-01-01

    Nowadays, vacuum grippers come in many different shapes and sizes. Their stability is guaranteed through specially manufactured metal fittings. These fittings are non-positively and positively connected to the elastic part of the vacuum gripper. The design of the elastic part may vary, though. Elastomer components are used to ensure tightness for the negative pressure in the active cave chamber of the vacuum gripper, as well as for the transfer of shearing forces, which acting parallel to the surface. Some vacuum grippers feature one elastomer for both the sealing function and the transfer of shear forces; other gripper types are equipped with various elastomers for those applications. The vacuum grippers described in this work are equipped with structured rubber friction pads, their tightness being ensured by sealing lips made of a flexible foam rubber. A restraint system consisting of one or several vacuum grippers must be sized prior to its actual practical use. For the transmission of shearing forces, which acting parallel to the surface, it is necessary to take the tribological system, consisting of the suction element's elastomer and the base material, into account since these loads put shearing stress on the vacuum gripper. In practice, however, a standardized value is given for the coefficient of friction μ; i.e. the ratio of transmissible frictional force to the normal force. This does neither include a detailed description of the elastomer used nor of the roughness of the base material. The standardized friction coefficients cannot be applied to the practical design of restraint systems. The present work includes the analysis of the load transmission and the modeling of the friction coefficients μ on rough surfaces during the shearing process of actively-driven vacuum grippers. Based on current theories, the phenomenon of elastomeric friction can be attributed to the two main components of hysteresis and adhesion friction. Both components are presented

  2. Gemini NIFS survey of feeding and feedback processes in nearby active galaxies - II. The sample and surface mass density profiles

    Science.gov (United States)

    Riffel, R. A.; Storchi-Bergmann, T.; Riffel, R.; Davies, R.; Bianchin, M.; Diniz, M. R.; Schönell, A. J.; Burtscher, L.; Crenshaw, M.; Fischer, T. C.; Dahmer-Hahn, L. G.; Dametto, N. Z.; Rosario, D.

    2018-02-01

    We present and characterize a sample of 20 nearby Seyfert galaxies selected for having BAT 14-195 keV luminosities LX ≥ 1041.5 erg s-1, redshift z ≤ 0.015, being accessible for observations with the Gemini Near-Infrared Field Spectrograph (NIFS) and showing extended [O III]λ5007 emission. Our goal is to study Active Galactic Nucleus (AGN) feeding and feedback processes from near-infrared integral-field spectra, which include both ionized (H II) and hot molecular (H2) emission. This sample is complemented by other nine Seyfert galaxies previously observed with NIFS. We show that the host galaxy properties (absolute magnitudes MB, MH, central stellar velocity dispersion and axial ratio) show a similar distribution to those of the 69 BAT AGN. For the 20 galaxies already observed, we present surface mass density (Σ) profiles for H II and H2 in their inner ˜500 pc, showing that H II emission presents a steeper radial gradient than H2. This can be attributed to the different excitation mechanisms: ionization by AGN radiation for H II and heating by X-rays for H2. The mean surface mass densities are in the range (0.2 ≤ ΣH II ≤ 35.9) M⊙ pc-2, and (0.2 ≤ ΣH2 ≤ 13.9)× 10-3 M⊙ pc-2, while the ratios between the H II and H2 masses range between ˜200 and 8000. The sample presented here will be used in future papers to map AGN gas excitation and kinematics, providing a census of the mass inflow and outflow rates and power as well as their relation with the AGN luminosity.

  3. Amphoteric surface active agents

    Directory of Open Access Journals (Sweden)

    Eissa, A.M. F.

    1995-10-01

    Full Text Available 2-[trimethyl ammonium, triethyl ammonium, pyridinium and 2-amino pyridinium] alkanoates, four series of surface active agents containing carbon chain C12, C14, C16 and C18carbon atoms, were prepared. Their structures were characterized by microanalysis, infrared (IR and nuclear magnetic resonance (NMR. Surface and interfacial tension, Krafft point, wetting time, emulsification power, foaming height and critical micelle concentration (cmc were determined and a comparative study was made between their chemical structure and surface active properties. Antimicrobial activity of these surfactants was also determined.

    Se prepararon cuatro series de agentes tensioactivos del tipo 2-[trimetil amonio, trietil amonio, piridinio y 2-amino piridinio] alcanoatos, que contienen cadenas carbonadas con C12, C14, C16 y C18 átomos de carbono.
    Se determinaron la tensión superficial e interfacial, el punto de Krafft, el tiempo humectante, el poder de emulsionamiento, la altura espumante y la concentración critica de miscela (cmc y se hizo un estudio comparativo entre la estructura química y sus propiedades tensioactivas. Se determinó también la actividad antimicrobiana de estos tensioactivos. Estas estructuras se caracterizaron por microanálisis, infrarrojo (IR y resonancia magnética nuclear (RMN.

  4. Surface Modification and Surface - Subsurface Exchange Processes on Europa

    Science.gov (United States)

    Phillips, C. B.; Molaro, J.; Hand, K. P.

    2017-12-01

    The surface of Jupiter's moon Europa is modified by exogenic processes such as sputtering, gardening, radiolysis, sulfur ion implantation, and thermal processing, as well as endogenic processes including tidal shaking, mass wasting, and the effects of subsurface tectonic and perhaps cryovolcanic activity. New materials are created or deposited on the surface (radiolysis, micrometeorite impacts, sulfur ion implantation, cryovolcanic plume deposits), modified in place (thermal segregation, sintering), transported either vertically or horizontally (sputtering, gardening, mass wasting, tectonic and cryovolcanic activity), or lost from Europa completely (sputtering, plumes, larger impacts). Some of these processes vary spatially, as visible in Europa's leading-trailing hemisphere brightness asymmetry. Endogenic geologic processes also vary spatially, depending on terrain type. The surface can be classified into general landform categories that include tectonic features (ridges, bands, cracks); disrupted "chaos-type" terrain (chaos blocks, matrix, domes, pits, spots); and impact craters (simple, complex, multi-ring). The spatial distribution of these terrain types is relatively random, with some differences in apex-antiapex cratering rates and latitudinal variation in chaos vs. tectonic features. In this work, we extrapolate surface processes and rates from the top meter of the surface in conjunction with global estimates of transport and resurfacing rates. We combine near-surface modification with an estimate of surface-subsurface (and vice versa) transport rates for various geologic terrains based on an average of proposed formation mechanisms, and a spatial distribution of each landform type over Europa's surface area. Understanding the rates and mass balance for each of these processes, as well as their spatial and temporal variability, allows us to estimate surface - subsurface exchange rates over the average surface age ( 50myr) of Europa. Quantifying the timescale

  5. Data-based diffraction kernels for surface waves from convolution and correlation processes through active seismic interferometry

    Science.gov (United States)

    Chmiel, Malgorzata; Roux, Philippe; Herrmann, Philippe; Rondeleux, Baptiste; Wathelet, Marc

    2018-05-01

    We investigated the construction of diffraction kernels for surface waves using two-point convolution and/or correlation from land active seismic data recorded in the context of exploration geophysics. The high density of controlled sources and receivers, combined with the application of the reciprocity principle, allows us to retrieve two-dimensional phase-oscillation diffraction kernels (DKs) of surface waves between any two source or receiver points in the medium at each frequency (up to 15 Hz, at least). These DKs are purely data-based as no model calculations and no synthetic data are needed. They naturally emerge from the interference patterns of the recorded wavefields projected on the dense array of sources and/or receivers. The DKs are used to obtain multi-mode dispersion relations of Rayleigh waves, from which near-surface shear velocity can be extracted. Using convolution versus correlation with a grid of active sources is an important step in understanding the physics of the retrieval of surface wave Green's functions. This provides the foundation for future studies based on noise sources or active sources with a sparse spatial distribution.

  6. Superhydrophobic surfaces by electrochemical processes.

    Science.gov (United States)

    Darmanin, Thierry; Taffin de Givenchy, Elisabeth; Amigoni, Sonia; Guittard, Frederic

    2013-03-13

    This review is an exhaustive representation of the electrochemical processes reported in the literature to produce superhydrophobic surfaces. Due to the intensive demand in the elaboration of superhydrophobic materials using low-cost, reproducible and fast methods, the use of strategies based on electrochemical processes have exponentially grown these last five years. These strategies are separated in two parts: the oxidation processes, such as oxidation of metals in solution, the anodization of metals or the electrodeposition of conducting polymers, and the reduction processed such as the electrodeposition of metals or the galvanic deposition. One of the main advantages of the electrochemical processes is the relative easiness to produce various surface morphologies and a precise control of the structures at a micro- or a nanoscale. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Radon transport processes below the earth's surface

    International Nuclear Information System (INIS)

    Wilkening, M.

    1980-01-01

    Processes by which 222 Rn is transported from the soil to the earth's surface are reviewed. The mechanisms effective in transporting 222 Rn to the surface are related to the size and configuration of the spaces occupied by the soil gas which may vary from molecular interstices to large underground caverns. The near-surface transport processes are divided into two categories: (1) a microscopic process that includes molecular diffusion and viscous flow in fine capillaries and (2) macroscopic flow in fissures and channels. Underground air rich in 222 Rn can also reach the surface through cracks, fissures, and underground channels. This type of transport is shown for (1) a horizontal tunnel penetrating a fractured hillside, (2) a large underground cave, and (3) volcanic activity. Pressure differentials having various natural origins and thermal gradients are responsible for the transport in these examples. 222 Rn transport by ordinary molecular diffusion appears to be the dominant process

  8. Nanoscale processes on insulating surfaces

    National Research Council Canada - National Science Library

    Gnecco, Enrico; Szymoński, Marek

    2009-01-01

    ... the group of Prof. Ernst Meyer in Basel, where he investigated friction processes on alkali halide surfaces in ultra high vacuum (UHV). The main result was the observation of a logarithmic velocity dependence of atomic friction, which was interpreted within a combination of the classical Tomlinson and Eyring models. After his Ph.D. he joined the ...

  9. Non-surface activity and micellization behavior of cationic amphiphilic block copolymer synthesized by reversible addition-fragmentation chain transfer process.

    Science.gov (United States)

    Ghosh, Arjun; Yusa, Shin-ichi; Matsuoka, Hideki; Saruwatari, Yoshiyuki

    2011-08-02

    Cationic amphiphilic diblock copolymers of poly(n-butylacrylate)-b-poly(3-(methacryloylamino)propyl)trimethylammonium chloride) (PBA-b-PMAPTAC) with various hydrophobic and hydrophilic chain lengths were synthesized by a reversible addition-fragmentation chain transfer (RAFT) process. Their molecular characteristics such as surface activity/nonactivity were investigated by surface tension measurements and foam formation observation. Their micelle formation behavior and micelle structure were investigated by fluorescence probe technique, static and dynamic light scattering (SLS and DLS), etc., as a function of hydrophilic and hydrophobic chain lengths. The block copolymers were found to be non-surface active because the surface tension of the aqueous solutions did not change with increasing polymer concentration. Critical micelle concentration (cmc) of the polymers could be determined by fluorescence and SLS measurements, which means that these polymers form micelles in bulk solution, although they were non-surface active. Above the cmc, the large blue shift of the emission maximum of N-phenyl-1-naphthylamine (NPN) probe and the low micropolarity value of the pyrene probe in polymer solution indicate the core of the micelle is nonpolar in nature. Also, the high value of the relative intensity of the NPN probe and the fluorescence anisotropy of the 1,6-diphenyl-1,3,5-hexatriene (DPH) probe indicated that the core of the micelle is highly viscous in nature. DLS was used to measure the average hydrodynamic radii and size distribution of the copolymer micelles. The copolymer with the longest PBA block had the poorest water solubility and consequently formed micelles with larger size while having a lower cmc. The "non-surface activity" was confirmed for cationic amphiphilic diblock copolymers in addition to anionic ones studied previously, indicating the universality of non-surface activity nature.

  10. Research on the Effects of Process Parameters on Surface Roughness in Wet-Activated Silicon Direct Bonding Base on Orthogonal Experiments

    Directory of Open Access Journals (Sweden)

    Lei NIE

    2015-11-01

    Full Text Available Surface roughness is a very important index in silicon direct bonding and it is affected by processing parameters in the wet-activated process. These parameters include the concentration of activation solution, holding time and treatment temperature. The effects of these parameters were investigated by means of orthogonal experiments. In order to analyze the wafer roughness more accurately, the bear ratio of the surface was used as the evaluation index. From the results of the experiments, it could be concluded that the concentration of the activation solution affected the roughness directly and the higher the concentration, the lower the roughness. Holding time did not affect the roughness as acutely as that of the concentration, but a reduced activation time decreased the roughness perceptibly. It was also discovered that the treatment temperature had a weak correlation with the surface roughness. Based on these conclusions, the parameters of concentration, temperature and holding time were optimized respectively as NH4OH:H2O2=1:1 (without water, 70 °C and 5 min. The results of bonding experiments proved the validity of the conclusions of orthogonal experiments.DOI: http://dx.doi.org/10.5755/j01.ms.21.4.9711

  11. Identification of microbes from the surfaces of food-processing lines based on the flow cytometric evaluation of cellular metabolic activity combined with cell sorting.

    Science.gov (United States)

    Juzwa, W; Duber, A; Myszka, K; Białas, W; Czaczyk, K

    2016-09-01

    In this study the design of a flow cytometry-based procedure to facilitate the detection of adherent bacteria from food-processing surfaces was evaluated. The measurement of the cellular redox potential (CRP) of microbial cells was combined with cell sorting for the identification of microorganisms. The procedure enhanced live/dead cell discrimination owing to the measurement of the cell physiology. The microbial contamination of the surface of a stainless steel conveyor used to process button mushrooms was evaluated in three independent experiments. The flow cytometry procedure provided a step towards monitoring of contamination and enabled the assessment of microbial food safety hazards by the discrimination of active, mid-active and non-active bacterial sub-populations based on determination of their cellular vitality and subsequently single cell sorting to isolate microbial strains from discriminated sub-populations. There was a significant correlation (r = 0.97; p vitality and the identification of species from defined sub-populations, although the identified microbes were limited to culturable cells.

  12. Synthesis of MOF having hydroxyl functional side groups and optimization of activation process for the maximization of its BET surface area

    International Nuclear Information System (INIS)

    Kim, Jongsik; Kim, Dong Ok; Kim, Dong Wook; Sagong, Kil

    2013-01-01

    To accomplish the postsynthetic modification of MOF with organic-metal precursors (OMPs) described in our previous researches more efficiently, synthesis of MOF (HCC-2) possessing relatively larger pore size as well as higher number of hydroxyl functional side groups per its base unit than those of HCC-1 has been successfully conducted via adopting 1,4-di-(4-carboxy-2,6-dihydroxyphenyl)benzene as an organic ligand and Zn(NO 3 ) 2 ·6H 2 O as a metal source, respectively. Also, optimization about the Activation process of HCC-2 was performed to maximize its BET (Brunauer–Emmett–Teller) surface area which was proved to be proportional to the number of exposed active sites on which its postsynthetic modification occurred. However, Activation process having been validated to be so effective with the acquirement of highly-purified HCC-1 (CO 2 supercritical drying step followed by vacuum drying step) was less satisfactory with the case of HCC-2. This might be attributed to relatively higher hydrophilicity and bulkier molecular structure of organic ligand of HCC-2. However, it was readily settled by simple modification of above Activation process. Moreover, indispensable residues composed of both DMF and its thermally degraded derivatives which were chemically attached via coordination bond with hydroxyl functionalities even after Activation process III might enable their H 2 adsorption properties to be seriously debased compared to that of IRMOF-16 having no hydroxyl functionalities. - Graphical abstract: Synthesis of new-structured MOF (HCC-2) simultaneously possessing relatively larger pore size as well as higher number of hydroxyl functional side groups per its base unit at the same time than those of HCC-1 has been performed via adopting 1,4-di-(4-carboxy-2,6-dihydroxyphenyl)benzene as an organic ligand and Zn(NO 3 ) 2 ·6H 2 O as a metal source, respectively. Also, the optimization of activation process for HCC-2 was conducted to maximize its BET surface area

  13. Optimization of process condition for the preparation of amine-impregnated activated carbon developed for CO2 capture and applied to methylene blue adsorption by response surface methodology.

    Science.gov (United States)

    Das, Dipa; Meikap, Bhim C

    2017-10-15

    The present research describes the optimal adsorption condition for methylene blue (MB). The adsorbent used here was monoethanol amine-impregnated activated carbon (MEA-AC) prepared from green coconut shell. Response surface methodology (RSM) is the multivariate statistical technique used for the optimization of the process variables. The central composite design is used to determine the effect of activation temperature, activation time and impregnation ratio on the MB removal. The percentage (%) MB adsorption by MEA-AC is evaluated as a response of the system. A quadratic model was developed for response. From the analysis of variance, the factor which was the most influential on the experimental design response has been identified. The optimum condition for the preparation of MEA-AC from green coconut shells is the temperature of activation 545.6°C, activation time of 41.64 min and impregnation ratio of 0.33 to achieve the maximum removal efficiency of 98.21%. At the same optimum parameter, the % MB removal from the textile-effluent industry was examined and found to be 96.44%.

  14. Surface migration in sorption processes

    International Nuclear Information System (INIS)

    Rasmuson, A.; Neretnieks, J.

    1983-03-01

    Diffusion rates of sorbing chemical species in granites and clays are in several experiments within the KBS study, higher than can be explained by pore diffusion only. One possible additional transport mechanism is transport of of sorbed molecules/ions along the intrapore surfaces. As a first step a literature investigation on on solid surfaces has been conducted. A lot of experimental evidence of the mobility of the sorbed molecules has been gathered through the years, particulary for metal surfaces and chemical engineering systems. For clays however, there are only a few articles, and for granites none. Two types of surface migration models have been proposed in the litterature: i) Surface flow as a result of a gradient in spreading pressure. ii) Surface diffusion as a result of a gradient in concentration. The surface flow model has only been applied to gaseous systems. However, it should be equally applicable to liquid systems. The models i) and ii) are conceptually very different. However, the resulting expressions for surface flux are complicated and it will not be an easy task to distinguish between them. There seem to be three ways of discriminating between the transport mechanisms: a) Temperature dependence. b) Concentration dependence. c) Order of magnitude. (Forf)

  15. Process Optimization of Ultrasonic-Assisted Extraction of Arabinogalactan from Dihydroquercetin Extracted Residues by Response Surface Methodology and Evaluation of Its Antioxidant Activity

    Directory of Open Access Journals (Sweden)

    Zaizhi Liu

    2013-01-01

    Full Text Available Ultrasound was used for the extraction of larch arabinogalactan from Larix gmelinii. The optimal conditions for ultrasound extraction were determined by response surface methodology. Specifically, the Box-Behnken design was employed to evaluate the effects of three independent variables: ultrasound time, temperature, and liquid-solid ratio. The highest arabinogalactan yield (11.18% was obtained under the optimal extraction condition (extraction temperature 41.5°C, extraction time 24.3 min, and liquid-solid ratio 40 mL/g. In addition, the antioxidant activity of arabinogalactan that was extracted from dihydroquercetin extraction residues exhibited a moderate and concentration-dependent hydroxyl radical-scavenging capacity, ferric-reducing power, and reducing power. The wood material was characterized before and after processing by scanning electron microscopy and Fourier-transform infrared spectroscopy.

  16. Surface-Activated Coupling Reactions Confined on a Surface.

    Science.gov (United States)

    Dong, Lei; Liu, Pei Nian; Lin, Nian

    2015-10-20

    Chemical reactions may take place in a pure phase of gas or liquid or at the interface of two phases (gas-solid or liquid-solid). Recently, the emerging field of "surface-confined coupling reactions" has attracted intensive attention. In this process, reactants, intermediates, and products of a coupling reaction are adsorbed on a solid-vacuum or a solid-liquid interface. The solid surface restricts all reaction steps on the interface, in other words, the reaction takes place within a lower-dimensional, for example, two-dimensional, space. Surface atoms that are fixed in the surface and adatoms that move on the surface often activate the surface-confined coupling reactions. The synergy of surface morphology and activity allow some reactions that are inefficient or prohibited in the gas or liquid phase to proceed efficiently when the reactions are confined on a surface. Over the past decade, dozens of well-known "textbook" coupling reactions have been shown to proceed as surface-confined coupling reactions. In most cases, the surface-confined coupling reactions were discovered by trial and error, and the reaction pathways are largely unknown. It is thus highly desirable to unravel the mechanisms, mechanisms of surface activation in particular, of the surface-confined coupling reactions. Because the reactions take place on surfaces, advanced surface science techniques can be applied to study the surface-confined coupling reactions. Among them, scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) are the two most extensively used experimental tools. The former resolves submolecular structures of individual reactants, intermediates, and products in real space, while the latter monitors the chemical states during the reactions in real time. Combination of the two methods provides unprecedented spatial and temporal information on the reaction pathways. The experimental findings are complemented by theoretical modeling. In particular, density

  17. Surface studies of plasma processed Nb samples

    International Nuclear Information System (INIS)

    Tyagi, Puneet V.; Doleans, Marc; Hannah, Brian S.; Afanador, Ralph; Stewart, Stephen; Mammosser, John; Howell, Matthew P; Saunders, Jeffrey W; Degraff, Brian D; Kim, Sang-Ho

    2015-01-01

    Contaminants present at top surface of superconducting radio frequency (SRF) cavities can act as field emitters and restrict the cavity accelerating gradient. A room temperature in-situ plasma processing technology for SRF cavities aiming to clean hydrocarbons from inner surface of cavities has been recently developed at the Spallation Neutron Source (SNS). Surface studies of the plasma-processed Nb samples by Secondary ion mass spectrometry (SIMS) and Scanning Kelvin Probe (SKP) showed that the NeO_2 plasma processing is very effective to remove carbonaceous contaminants from top surface and improves the surface work function by 0.5 to 1.0 eV.

  18. Technical activities, 1990: Surface Science Division

    International Nuclear Information System (INIS)

    Powell, C.J.

    1991-05-01

    The report summarizes technical activities and accomplishments of the NIST Surface Science Division during Fiscal Year 1990. Overviews are presented of the Division and of its three constituent groups: Surface Dynamical Processes, Thin Films and Interfaces, and Surface Spectroscopies and Standards. These overviews are followed by reports of selected technical accomplishments during the year. A summary is given of Division outputs and interactions that includes lists of publications, talks, committee assignments, seminars (including both Division seminars and Interface Science seminars arranged through the Division), conferences organized, and a standard reference material certified. Finally, lists are given of Division staff and of guest scientists who have worked in the Division during the past year

  19. Description of two-process surface topography

    International Nuclear Information System (INIS)

    Grabon, W; Pawlus, P

    2014-01-01

    After two machining processes, a large number of surface topography measurements were made using Talyscan 150 stylus measuring equipment. The measured samples were divided into two groups. The first group contained two-process surfaces of random nature, while the second group used random-deterministic textures of random plateau parts and portions of deterministic valleys. For comparison, one-process surfaces were also analysed. Correlation and regression analysis was used to study the dependencies among surface texture parameters in 2D and 3D systems. As the result of this study, sets of parameters describing multi-process surface topography were obtained for two-process surfaces of random and of random-deterministic types. (papers)

  20. High surface area carbon and process for its production

    Energy Technology Data Exchange (ETDEWEB)

    Romanos, Jimmy; Burress, Jacob; Pfeifer, Peter; Rash, Tyler; Shah, Parag; Suppes, Galen

    2016-12-13

    Activated carbon materials and methods of producing and using activated carbon materials are provided. In particular, biomass-derived activated carbon materials and processes of producing the activated carbon materials with prespecified surface areas and pore size distributions are provided. Activated carbon materials with preselected high specific surface areas, porosities, sub-nm (<1 nm) pore volumes, and supra-nm (1-5 nm) pore volumes may be achieved by controlling the degree of carbon consumption and metallic potassium intercalation into the carbon lattice during the activation process.

  1. Earth Surface Processes, Landforms and Sediment Deposits

    Science.gov (United States)

    Bridge, John; Demicco, Robert

    Earth surface processes, landforms and sediment deposits are intimately related - involving erosion of rocks, generation of sediment, and transport and deposition of sediment through various Earth surface environments. These processes, and the landforms and deposits that they generate, have a fundamental bearing on engineering, environmental and public safety issues; on recovery of economic resources; and on our understanding of Earth history. This unique textbook brings together the traditional disciplines of sedimentology and geomorphology to explain Earth surface processes, landforms and sediment deposits in a comprehensive and integrated way. It is the ideal resource for a two-semester course in sedimentology, stratigraphy, geomorphology, and Earth surface processes from the intermediate undergraduate to beginning graduate level. The book is also accompanied by a website hosting illustrations and material on field and laboratory methods for measuring, describing and analyzing Earth surface processes, landforms and sediments.

  2. Plasma surface interaction processes and possible synergisms

    International Nuclear Information System (INIS)

    Behrisch, R.; Roberto, J.B.

    1984-08-01

    The process determining the plasma surface interaction in today's high temperature plasma experiments are investigated following several lines. First, in plasma devices, the particle and energy fluxes to the different first wall areas the fluxes from the walls back into the plasma are measured and the boundary plasma parameters are determined. The surface composition and structure of the walls, limiters and divertor plates are analyzed following exposure to many discharges. Secondly, the different surface processes which are expected to contribute to the plasma surface interaction (particularly to hydrogen particle balance and impurity introduction) are studied in simulation experiments using well defined particle beams

  3. Surface Energy and Setting Process of Contacting Surfaces

    Directory of Open Access Journals (Sweden)

    M. V. Musokhranov

    2014-01-01

    Full Text Available The paper deals with a challenge in terms of ensuring an accuracy of the relative position of the conjugated surfaces that is to determine a coefficient of friction. To solve it, there is a proposal to use the surface energy, as a tool that influences the contacting parts nature. Presently, energy of the surface layers at best is only stated, but not used in practice.Analysis of the conditions of interaction between two contacting surfaces, such as seizing and setting cannot be explained only from the position of the roughness parameters. It is found that these phenomena are explained by the appearing gripe (setting bridges, which result from the energy of interaction between two or more adjacent surfaces. The emerging phenomenon such as micro welding, i.e. occurring bonds, is caused by the overflow of energy, according to the theory of physics, from the surface with a high level of energy to the surface with the smaller one to balance the system as a whole.The paper shows that through the use of process, controlling the depth of the surface layer and creating a certain structure, the energy level of the material as a whole can be specified. And this will allow us to provide the necessary performance and mechanical properties. It means to create as many gripe bridges as possible to ensure continuous positioning i.e. a fixed connection of the contacting surfaces.It was determined that to increase a value of the friction coefficient, the physical and mechanical properties of the surface layer of the parts material must be taken into account, namely, in the part body accumulate the energy to be consumed for forming the surface.The paper gives recommendations for including the parts of the surface energy in the qualitative indicators of characteristics. This will make a technologist, when routing a process, to choose such operations and modes to provide the designer-specified parameters not only of the accuracy and surface finish, but also of the

  4. Processing and finishing of granite surfaces

    OpenAIRE

    Klich, J. (Jiří); Hlaváček, P. (Petr); Ščučka, J. (Jiří); Sitek, L. (Libor); Foldyna, J. (Josef); Georgiovská, L. (Lucie); Souček, K. (Kamil); Staš, L. (Lubomír); Bortolussi, A.

    2013-01-01

    The article deals with granite surface processing and finishing by various methods including bush hammering, flaming, polishing, continuous and pulsating water jetting. Both optical and CT X-ray methods are used for analysis of surface and subsurface areas of tested samples. Advantages of pulsating water jetting compared to other techniques are discussed.

  5. Surface active monomers synthesis, properties, and application

    CERN Document Server

    Borzenkov, Mykola

    2014-01-01

    This brief includes information on the background?of and development of synthesis of various types of surface active monomers. The authors explain the importance of utilization of surface active monomers for creation of surface active polymers? and the various biomedical applications of such compounds . This brief introduces techniques for the synthesis of novel types of surface active monomers, their colloidal and polymerizable properties and application for needs of medicine and biology.

  6. Mechanisms and energetics of surface atomic processes

    International Nuclear Information System (INIS)

    Tsong, T.T.

    1991-01-01

    The energies involved in various surface atomic processes such as surface diffusion, the binding of small atomic clusters on the surface, the interaction between two adsorbed atoms, the dissociation of an atom from a small cluster or from a surface layer, the binding of kink size atoms or atoms at different adsorption sites to the surface etc., can be derived from an analysis of atomically resolved field ion microscope images and a kinetic energy measurement of low temperature field desorbed ions using the time-of-flight atom-probe field ion microscope. These energies can be used to compare with theories and to understand the transport of atoms on the surface in atomic reconstructions, epitaxial growth of surface layers and crystal growth, adsorption layer superstructure formation, and also why an atomic ordering or atomic reconstruction at the surface is energetically favored. Mechanisms of some of the surface atomic processes are also clarified from these quantitative, atomic resolution studies. In this paper work in this area is bris briefly reviewed

  7. Quantitative Modeling of Earth Surface Processes

    Science.gov (United States)

    Pelletier, Jon D.

    This textbook describes some of the most effective and straightforward quantitative techniques for modeling Earth surface processes. By emphasizing a core set of equations and solution techniques, the book presents state-of-the-art models currently employed in Earth surface process research, as well as a set of simple but practical research tools. Detailed case studies demonstrate application of the methods to a wide variety of processes including hillslope, fluvial, aeolian, glacial, tectonic, and climatic systems. Exercises at the end of each chapter begin with simple calculations and then progress to more sophisticated problems that require computer programming. All the necessary computer codes are available online at www.cambridge.org/9780521855976. Assuming some knowledge of calculus and basic programming experience, this quantitative textbook is designed for advanced geomorphology courses and as a reference book for professional researchers in Earth and planetary science looking for a quantitative approach to Earth surface processes. More details...

  8. Optimization of Extraction Process for Antidiabetic and Antioxidant Activities of Kursi Wufarikun Ziyabit Using Response Surface Methodology and Quantitative Analysis of Main Components.

    Science.gov (United States)

    Edirs, Salamet; Turak, Ablajan; Numonov, Sodik; Xin, Xuelei; Aisa, Haji Akber

    2017-01-01

    By using extraction yield, total polyphenolic content, antidiabetic activities (PTP-1B and α -glycosidase), and antioxidant activity (ABTS and DPPH) as indicated markers, the extraction conditions of the prescription Kursi Wufarikun Ziyabit (KWZ) were optimized by response surface methodology (RSM). Independent variables were ethanol concentration, extraction temperature, solid-to-solvent ratio, and extraction time. The result of RSM analysis showed that the four variables investigated have a significant effect ( p analysis of effective part of KWZ was characterized via UPLC method, 12 main components were identified by standard compounds, and all of them have shown good regression within the test ranges and the total content of them was 11.18%.

  9. Surface quality in rapid prototype MMD process

    Directory of Open Access Journals (Sweden)

    Lisandro Vargas Henríquez

    2004-09-01

    Full Text Available This article summarises a Manufacturing Materials and Processes MSc thesis written for the Mechanical and Electrical Engineering Department. The paper shows the interaction of process, gap (deposition distance and extursion terminal velocity modelled process parameters for CEIF's (Centro de Equipos Interfacultades rapid prototype molten material deposit (MMD Titan SH-1 machine by analysing prototupes improved surface quality and resistence to tension and characterising material. The project applies experimental design criteria for orientating the selection of experimental process parameters. Acrylonitrile-buttadin-styrene (ABS had alredy been mechanically and physicochemically characterised (i.e the material used in the MMD process.

  10. THE PRODUCT DESIGN PROCESS USING STYLISTIC SURFACES

    Directory of Open Access Journals (Sweden)

    Arkadiusz Gita

    2017-06-01

    Full Text Available The increasing consumer requirements for the way what everyday use products look like, forces manufacturers to put more emphasis on product design. Constructors, apart from the functional aspects of the parts created, are forced to pay attention to the aesthetic aspects. Software for designing A-class surfaces is very helpful in this case. Extensive quality analysis modules facilitate the work and allow getting models with specific visual features. The authors present a design process of the product using stylistic surfaces based on the front panel of the moped casing. In addition, methods of analysis of the design surface and product technology are presented.

  11. The interaction of C60 on Si(111 7x7 studied by Supersonic Molecular Beams: interplay between precursor kinetic energy and substrate temperature in surface activated processes.

    Directory of Open Access Journals (Sweden)

    Lucrezia eAversa

    2015-06-01

    Full Text Available Buckminsterfullerene (C60 is a molecule fully formed of carbon that can be used, owing to its electronic and mechanical properties, as clean precursor for the growth of carbon-based materials, ranging from -conjugated systems (graphenes to synthesized species, e.g. carbides such as silicon carbide (SiC. To this goal, C60 cage rupture is the main physical process that triggers material growth. Cage breaking can be obtained either thermally by heating up the substrate to high temperatures (630°C, after C60 physisorption, or kinetically by using Supersonic Molecular Beam Epitaxy (SuMBE techniques. In this work, aiming at demonstrating the growth of SiC thin films by C60 supersonic beams, we present the experimental investigation of C60 impacts on Si(111 7x7 kept at 500°C for translational kinetic energies ranging from 18 to 30 eV. The attained kinetically activated synthesis of SiC submonolayer films is probed by in-situ surface electron spectroscopies (XPS and UPS. Furthermore, in these experimental conditions the C60-Si(111 7×7 collision has been studied by computer simulations based on a tight-binding approximation to Density Functional Theory, DFT. Our theoretical and experimental findings point towards a kinetically driven growth of SiC on Si, where C60 precursor kinetic energy plays a crucial role, while temperature is relevant only after cage rupture to enhance Si and carbon reactivity. In particular, we observe a counterintuitive effect in which for low kinetic energy (below 22 eV, C60 bounces back without breaking more effectively at high temperature due to energy transfer from excited phonons. At higher kinetic energy (22 < K < 30 eV, for which cage rupture occurs, temperature enhances reactivity without playing a major role in the cage break. These results are in good agreement with ab-initio molecular dynamics simulations. SuMBE is thus a technique able to drive materials growth at low temperature regime.

  12. Surface analytical techniques applied to minerals processing

    International Nuclear Information System (INIS)

    Smart, R.St.C.

    1991-01-01

    An understanding of the chemical and physical forms of the chemically altered layers on the surfaces of base metal sulphides, particularly in the form of hydroxides, oxyhydroxides and oxides, and the changes that occur in them during minerals processing lies at the core of a complete description of flotation chemistry. This paper reviews the application of a variety of surface-sensitive techniques and methodologies applied to the study of surface layers on single minerals, mixed minerals, synthetic ores and real ores. Evidence from combined XPS/SAM/SEM studies have provided images and analyses of three forms of oxide, oxyhydroxide and hydroxide products on the surfaces of single sulphide minerals, mineral mixtures and complex sulphide ores. 4 refs., 2 tabs., 4 figs

  13. Process for cleaning radioactively contaminated metal surfaces

    International Nuclear Information System (INIS)

    Mihram, R.G.; Snyder, G.A.

    1975-01-01

    A process is described for removing radioactive scale from a ferrous metal surface, including the steps of initially preconditioning the surface by contacting it with an oxidizing solution (such as an aqueous solution of an alkali metal permanganate or hydrogen peroxide), then, after removal or decomposition of the oxidizing solution, the metallic surface is contacted with a cleaning solution which is a mixture of a mineral acid and a complexing agent (such as sulfuric acid and oxalic acid), and which preferably contains a corrosion inhibitor. A final step in the process is the treatment of the spent cleaning solution containing radioactive waste materials in solution by adding a reagent selected from the group consisting of calcium hydroxide or potassium permanganate and an alkali metal hydroxide to thereby form easily recovered metallic compounds containing substantially all of the dissolved metals and radioactivity. (auth)

  14. Surface-Assisted Dynamic Search Processes.

    Science.gov (United States)

    Shin, Jaeoh; Kolomeisky, Anatoly B

    2018-03-01

    Many chemical and biological systems exhibit intermittent search phenomena when participating particles alternate between dynamic regimes with different dimensionalities. Here we investigate theoretically a dynamic search process of finding a small target on a two-dimensional surface starting from a bulk solution, which is an example of such an intermittent search process. Both continuum and discrete-state stochastic descriptions are developed. It is found that depending on the scanning length λ, which describes the area visited by the reacting molecule during one search cycle, the system can exhibit three different search regimes: (i) For small λ values, the reactant finds the target mostly via three-dimensional bulk diffusion; (ii) for large λ values, the reactant molecule associates to the target mostly via surface diffusion; and (iii) for intermediate λ values, the reactant reaches the target via a combination of three-dimensional and two-dimensional search cycles. Our analysis also shows that the mean search times have different scalings as a function of the size of the surface segment depending on the nature of the dynamic search regime. Search dynamics are also sensitive to the position of the target for large scanning lengths. In addition, it is argued that the continuum description underestimates mean search times and does not always correctly describe the most optimal conditions for the surface-assisted dynamic processes. The importance of our findings for real natural systems is discussed.

  15. Electronic dissipation processes during chemical reactions on surfaces

    CERN Document Server

    Stella, Kevin

    2012-01-01

    Hauptbeschreibung Every day in our life is larded with a huge number of chemical reactions on surfaces. Some reactions occur immediately, for others an activation energy has to be supplied. Thus it happens that though a reaction should thermodynamically run off, it is kinetically hindered. Meaning the partners react only to the thermodynamically more stable product state within a mentionable time if the activation energy of the reaction is supplied. With the help of catalysts the activation energy of a reaction can be lowered. Such catalytic processes on surfaces are widely used in industry. A

  16. Array processing for seismic surface waves

    Energy Technology Data Exchange (ETDEWEB)

    Marano, S.

    2013-07-01

    This dissertation submitted to the Swiss Federal Institute of Technology ETH in Zurich takes a look at the analysis of surface wave properties which allows geophysicists to gain insight into the structure of the subsoil, thus avoiding more expensive invasive techniques such as borehole drilling. This thesis aims at improving signal processing techniques for the analysis of surface waves in various directions. One main contribution of this work is the development of a method for the analysis of seismic surface waves. The method also deals with the simultaneous presence of multiple waves. Several computational approaches to minimize costs are presented and compared. Finally, numerical experiments that verify the effectiveness of the proposed cost function and resulting array geometry designs are presented. These lead to greatly improved estimation performance in comparison to arbitrary array geometries.

  17. Array processing for seismic surface waves

    International Nuclear Information System (INIS)

    Marano, S.

    2013-01-01

    This dissertation submitted to the Swiss Federal Institute of Technology ETH in Zurich takes a look at the analysis of surface wave properties which allows geophysicists to gain insight into the structure of the subsoil, thus avoiding more expensive invasive techniques such as borehole drilling. This thesis aims at improving signal processing techniques for the analysis of surface waves in various directions. One main contribution of this work is the development of a method for the analysis of seismic surface waves. The method also deals with the simultaneous presence of multiple waves. Several computational approaches to minimize costs are presented and compared. Finally, numerical experiments that verify the effectiveness of the proposed cost function and resulting array geometry designs are presented. These lead to greatly improved estimation performance in comparison to arbitrary array geometries

  18. Electrolytic plasma processing of steel surfaces

    International Nuclear Information System (INIS)

    Bejar, M.A; Araya, R.N; Baeza, B

    2006-01-01

    The thermo-chemical treatments of steels with plasma is normally carried out in low-pressure ionized gaseous atmospheres. Among the treatments used most often are: nitruration, carburization and boronized. A plasma can also generate at atmospheric pressure. One way to produce it is with an electrochemical cell that works at a relatively high inter-electrode voltage and under conditions of heavy gas generation. This type of plasma is known as electrolytic plasma. This work studies the feasibility of using electrolytic plasma for the surface processing of steels. Two processes were selected: boronized and nitruration., for the hardening of two types of steel: one with low carbon (1020) and one with low alloy (4140). In the case of the nitruration, the 1020 steel was first aluminized. The electrolytes were aqueous solutions of borax for the boronizing and urea for the nitruration. The electrolytic plasmas were classified qualitatively, in relation with their luminosity by low, medium and high intensity. The boronizing was carried out with low intensity plasmas for a period of one hour. The nitruration was performed with plasmas of different intensities and for period of a few minutes to half an hour. The test pieces processed by electrolytic plasma were characterized by micro-hardness tests and X-ray diffraction. The maximum surface hardnesses obtained for the 1020 and 4140 steels were the following: 300 and 700 HV for the boronizing, and 1650 and 1200 HV for the nitruration, respectively. The utilization of an electrolytic plasma permits the surface processing of steels, noticeably increasing their hardness. With this type of plasma some thermo-chemical surface treatments can be done very rapidly as well (CW)

  19. ENVISAT Land Surface Processes. Phase 2

    Science.gov (United States)

    vandenHurk, B. J. J. M.; Su, Z.; Verhoef, W.; Menenti, M.; Li, Z.-L.; Wan, Z.; Moene, A. F.; Roerink, G.; Jia, I.

    2002-01-01

    This is a progress report of the 2nd phase of the project ENVISAT- Land Surface Processes, which has a 3-year scope. In this project, preparative research is carried out aiming at the retrieval of land surface characteristics from the ENVISAT sensors MERIS and AATSR, for assimilation into a system for Numerical Weather Prediction (NWP). Where in the 1st phase a number of first shot experiments were carried out (aiming at gaining experience with the retrievals and data assimilation procedures), the current 2nd phase has put more emphasis on the assessment and improvement of the quality of the retrieved products. The forthcoming phase will be devoted mainly to the data assimilation experiments and the assessment of the added value of the future ENVISAT products for NWP forecast skill. Referring to the retrieval of albedo, leaf area index and atmospheric corrections, preliminary radiative transfer calculations have been carried out that should enable the retrieval of these parameters once AATSR and MERIS data become available. However, much of this work is still to be carried out. An essential part of work in this area is the design and implementation of software that enables an efficient use of MODTRAN(sub 4) radiative transfer code, and during the current project phase familiarization with these new components has been achieved. Significant progress has been made with the retrieval of component temperatures from directional ATSR-images, and the calculation of surface turbulent heat fluxes from these data. The impact of vegetation cover on the retrieved component temperatures appears manageable, and preliminary comparison of foliage temperature to air temperatures were encouraging. The calculation of surface fluxes using the SEBI concept,which includes a detailed model of the surface roughness ratio, appeared to give results that were in reasonable agreement with local measurements with scintillometer devices. The specification of the atmospheric boundary conditions

  20. Two photon processes in surface photovoltage spectroscopy

    International Nuclear Information System (INIS)

    Craig, R.P.; Thurgate, S.M.

    1996-01-01

    Full text: A significant mid-gap effect has been found in Surface Photovoltage Spectroscopy measurements of cleaved GaAs, InP and Si wafer which is normally interpreted as arising from transitions between surface states and band edges. This large mid-gap effect common to various materials is puzzling as such a high proportion of mid-gap states seems unlikely. Most theories of surface states predict states that tail from the band edges into the gap or states that have a well defined energy in the gap. None propose a large state exactly at E G /2. We recently investigated the variation in SPS spectra with flux density. We find a non-linear correlation in the magnitude of Band-Bending arising from mid-gap and band-gap photon energies. We suggest that the mid-gap feature is due to a two photon absorption process leading to carrier pair generation mediated by mid-gap states in the continuum of band-gap surface states

  1. Modification of surfaces and surface layers by non equilibrium processes

    International Nuclear Information System (INIS)

    Beamson, G.; Brennan, W.J.; Clark, D.T.; Howard, J.

    1988-01-01

    Plasmas are examples of non-equilibrium phenomena which are being used increasingly for the synthesis and modification of materials impossible by conventional routes. This paper introduces methods available by describing the construction and characteristics of some equipment used for the production of different types of plasmas and other non-equilibrium phenomena. This includes high energy ion beams. The special features, advantages and disadvantages of the techniques will be described. There are a multitude of potential application relevant to electronic, metallic, ceramic, and polymeric materials. However, scale-up from the laboratory to production equipment depends on establishing a better understanding of both the physics and chemistry of plasma as well as plasma-solid interactions. Examples are given of how such an understanding can be gained. The chemical analysis of polymer surfaces undergoing modification by inert gas, hydrogen or oxygen plasmas is shown to give physical information regarding the relative roles of diffusion of active species, and direct and radiative energy transfer from the plasma. Surface modification by plasma depositing a new material onto an existing substrate is discussed with particular reference to the deposition of amorphous carbon films. Applications of the unique properties of these films are outlined together with our current understanding of these properties based on chemical and physical methods of analysis of both the films and the plasmas producing them. Finally, surface modification by ion beams is briefly illustrated using examples from the electronics and metals industries where the modification has had a largely physical rather than chemical effect on the starting material. (orig.)

  2. Surface active agents from Egyptian petroleum distillates

    Energy Technology Data Exchange (ETDEWEB)

    Kassem, T.M.

    Kerosene and solar distillates from local crude petroleum 'Morgan' were fractionated. These fractions were refined with oleum and then distilled. The normal paraffins were separated from the refined fractions by the urea adduction technique. These paraffin cuts were subjected to 50% chlorination and the obtained monochlorinated paraffins were used in the synthesis of alkylbenzenes and alkyldiphenyls which were converted to anionic surfactants by sulphonation with 95% sulphuric acid. The sulphonyl chlorides of alkylbenzenes and of alkyldiphenyls were prepared and then converted to the corresponding sulphonamides. The prepared sulphonamides were then processed to nonionic surfactants through condensation with ethylene oxide. The ethoxylates were sulphated with chlorosulphonic acid and phosphated with phosphorus pentoxide to anionic surfactants. The surface active properties and the biodegradability of all the prepared surfactants were determined.

  3. Does Titan have an Active Surface?

    Science.gov (United States)

    Nelson, R.

    2009-12-01

    ammonia, a compound expected in Titan’s interior. This, combined with the previous evidence from VIMS and RADAR images, creates a strong case for Titan having a presently active surface, possibly due to cryovolcanism. Cassini encountered Titan at very close range on 2008-11-19-13:58 and again on 2008-12-05-12:38. These epochs are called T47 and T48. Comparison of earlier lower resolution data (T5) with the recent T47 and T48 data reveal changes of the surface reflectance and morphology in the Hotei region. This is the first evidence from VIMS that confirms the RADAR report that Hotei Reggio has morphology consistent with volcanic terrain. It has not escaped our attention that ammonia, in association with methane and nitrogen, the principal species of Titan’s atmosphere, closely replicates the environment at the time that live first emerged on earth. If Titan is currently active then these results raise the following questions: What is the full extent of current geologic activity? What are the ongoing processes? Are Titan’s chemical processes today supporting a prebiotic chemistry similar to that under which life evolved on Earth? This work done at JPL under contract with NASA. Refs: [1]R. M. Nelson et al., Icarus 199 (2009) 429-441. [2]R. M. Nelson et al., GRL, VOL. 36, L04202, doi:10.1029/2008GL036206, 2009. [3]S. D. Wall GRL, VOL. 36, L04203, doi:10.1029/2008GL036415, 2009

  4. High-surface-area active carbon

    International Nuclear Information System (INIS)

    O'Grady, T.M.; Wennerberg, A.N.

    1986-01-01

    This paper describes the preparation and properties of a unique active carbon having exceptionally high surface areas, over 2500 m 2 /gm, and extraordinary adsorptive capacities. The carbon is made by a direct chemical activation route in which petroleum coke or other carbonaceous sources are reacted with excess potassium hydroxide at 400 0 to 500 0 C to an intermediate product that is subsequently pyrolyzed at 800 0 to 900 0 C to active carbon containing potassium salts. These are removed by water washing and the carbon is dried to produce a powdered product. A granular carbon can also be made by further processing the powdered carbon by using specialized granulation techniques. Typical properties of the carbon include Iodine Numbers of 3000 to 3600, methylene blue adsorption of 650 to 750 mg/gm, pore volumes of 2.0 to 2.6 cc/gm and less than 3.0% ash. This carbon's high adsorption capacities make it uniquely suited for numerous demanding applications in the medical area, purifications, removal of toxic substances, as catalyst carriers, etc

  5. Surface processing by high power excimer laser

    Energy Technology Data Exchange (ETDEWEB)

    Stehle, M [SOPRA, 92 - Bois-Colombes (France)

    1995-03-01

    Surface processing with lasers is a promising field of research and applications because lasers bring substantial advantages : laser beams work at distance, laser treatments are clean in respect of environment consideration and they offer innovative capabilities for surface treatment which cannot be reached by other way. Excimer lasers are pulsed, gaseous lasers which emit in UV spectral range - the most common are XeCl (308 nm), KrF (248 nm), ArF (193 nm). From 1980 up to 1994, many of them have been used for research, medical and industrial applications such as spectroscopy, PRK (photo-refractive keratotomy) and micro-machining. In the last six years, from 1987 up to 1993, efforts have been done in order to jump from 100 W average power up to 1 kW for XeCl laser at {lambda} = 308 nm. It was the aim of AMMTRA project in Japan as EU205 and EU213 Eureka projects in Europe. In this framework, SOPRA developed VEL (Very large Excimer Laser). In 1992, 1 kW (10 J x 100 Hz) millstone has been reached for the first time, this technology is based on X-Ray preionization and large laser medium (5 liters). Surface treatments based on this laser source are the main purpose of VEL Lasers. Some of them are given for instance : (a) Turbine blades made with metallic substrate and ceramic coatings on the top, are glazed in order to increase corrosion resistance of ceramic and metal sandwich. (b) Selective ablation of organic coatings deposited on fragile composite material is investigated in Aerospace industry. (c) Chock hardening of bulk metallic materials or alloys are investigated for automotive industry in order to increase wear resistance. (d) Ablation of thin surface oxides of polluted steels are under investigation in nuclear industry for decontamination. (J.P.N.).

  6. Surface processing by high power excimer laser

    International Nuclear Information System (INIS)

    Stehle, M.

    1995-01-01

    Surface processing with lasers is a promising field of research and applications because lasers bring substantial advantages : laser beams work at distance, laser treatments are clean in respect of environment consideration and they offer innovative capabilities for surface treatment which cannot be reached by other way. Excimer lasers are pulsed, gaseous lasers which emit in UV spectral range - the most common are XeCl (308 nm), KrF (248 nm), ArF (193 nm). From 1980 up to 1994, many of them have been used for research, medical and industrial applications such as spectroscopy, PRK (photo-refractive keratotomy) and micro-machining. In the last six years, from 1987 up to 1993, efforts have been done in order to jump from 100 W average power up to 1 kW for XeCl laser at λ = 308 nm. It was the aim of AMMTRA project in Japan as EU205 and EU213 Eureka projects in Europe. In this framework, SOPRA developed VEL (Very large Excimer Laser). In 1992, 1 kW (10 J x 100 Hz) millstone has been reached for the first time, this technology is based on X-Ray preionization and large laser medium (5 liters). Surface treatments based on this laser source are the main purpose of VEL Lasers. Some of them are given for instance : a) Turbine blades made with metallic substrate and ceramic coatings on the top, are glazed in order to increase corrosion resistance of ceramic and metal sandwich. b) Selective ablation of organic coatings deposited on fragile composite material is investigated in Aerospace industry. c) Chock hardening of bulk metallic materials or alloys are investigated for automotive industry in order to increase wear resistance. d) Ablation of thin surface oxides of polluted steels are under investigation in nuclear industry for decontamination. (J.P.N.)

  7. Active Surface Compensation for Large Radio Telescope Antennas

    Directory of Open Access Journals (Sweden)

    Congsi Wang

    2018-01-01

    Full Text Available With the development of radio telescope antennas with large apertures, high gain, and wide frequency bands, compensation methods, such as mechanical or electronic compensation, are obviously essential to ensure the electrical performance of antennas that work in complex environments. Since traditional compensation methods can only adjust antenna pointing but not the surface accuracy, which are limited for obtaining high surface precision and aperture efficiency, active surface adjustment has become an indispensable tool in this field. Therefore, the development process of electrical performance compensation methods for radio telescope antennas is introduced. Further, a series of analyses of the five key technologies of active surface adjustment is presented. Then, four typical large antennas that have been designed with active main reflector technology are presented and compared. Finally, future research directions and suggestions for reflector antenna compensation methods based on active surface adjustment are presented.

  8. Changes of the surface structure of corn stalk in the cooking process with active oxygen and MgO-based solid alkali as a pretreatment of its biomass conversion.

    Science.gov (United States)

    Pang, Chunsheng; Xie, Tujun; Lin, Lu; Zhuang, Junping; Liu, Ying; Shi, Jianbin; Yang, Qiulin

    2012-01-01

    This study presents a novel, efficient and environmentally friendly process for the cooking of corn stalk that uses active oxygen (O2 and H2O2) and a recoverable solid alkali (MgO). The structural changes on the surface of corn stalk before and after cooking were characterized by attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) techniques. The results showed that lignin and extractives were effectively removed, especially those on the surface of corn stalk. Additionally, the changes included becoming fibrillar, the exposure of cellulose and hemi-cellulose and the pitting corrosion on the surface, etc. The results also showed that the removal reaction is from outside to inside, but the main reaction is possibly on the surface. Furthermore, the results of active oxygen cooking with a solid alkali are compared with those of alkaline cooking in the paper. Copyright © 2011 Elsevier Ltd. All rights reserved.

  9. Active micromixer using surface acoustic wave streaming

    Science.gov (United States)

    Branch,; Darren W. , Meyer; Grant D. , Craighead; Harold, G [Ithaca, NY

    2011-05-17

    An active micromixer uses a surface acoustic wave, preferably a Rayleigh wave, propagating on a piezoelectric substrate to induce acoustic streaming in a fluid in a microfluidic channel. The surface acoustic wave can be generated by applying an RF excitation signal to at least one interdigital transducer on the piezoelectric substrate. The active micromixer can rapidly mix quiescent fluids or laminar streams in low Reynolds number flows. The active micromixer has no moving parts (other than the SAW transducer) and is, therefore, more reliable, less damaging to sensitive fluids, and less susceptible to fouling and channel clogging than other types of active and passive micromixers. The active micromixer is adaptable to a wide range of geometries, can be easily fabricated, and can be integrated in a microfluidic system, reducing dead volume. Finally, the active micromixer has on-demand on/off mixing capability and can be operated at low power.

  10. Plasma technology of the surface polymer activation

    International Nuclear Information System (INIS)

    Dutra, Jorge C.N.; Mello, Sandra C.; Massi, Marcos; Otani, Choyu; Maciel, Homero S.; Bittencourt, Edison

    2005-01-01

    A number of polymers, especially rubbers, require surface treatment to achieve a satisfactory level of adhesion. The surface of EPDM rubber vulcanized is high hydrophobicity and is not suited for a number of potential applications, in particular, for adhering to the polyurethane liner of solid rocket propellants. In this case, plasma treatment can be a very attractive process because it can efficiently increase the surface energy attributed to surface oxidation with the introduction of polar groups 1, 2. In order to investigate the influence of the parameters on the modifications of the treated surface samples of EPDM rubber by plasma generated by gas oxygen and argon, the water and methylene iodide contact angles were measured at room temperature with an image analyzing using the sessile drop technique 3 - 6 . (author)

  11. Active Surfaces and Interfaces of Soft Materials

    Science.gov (United States)

    Wang, Qiming

    A variety of intriguing surface patterns have been observed on developing natural systems, ranging from corrugated surface of white blood cells at nanometer scales to wrinkled dog skins at millimeter scales. To mimetically harness functionalities of natural morphologies, artificial transformative skin systems by using soft active materials have been rationally designed to generate versatile patterns for a variety of engineering applications. The study of the mechanics and design of these dynamic surface patterns on soft active materials are both physically interesting and technologically important. This dissertation starts with studying abundant surface patterns in Nature by constructing a unified phase diagram of surface instabilities on soft materials with minimum numbers of physical parameters. Guided by this integrated phase diagram, an electroactive system is designed to investigate a variety of electrically-induced surface instabilities of elastomers, including electro-creasing, electro-cratering, electro-wrinkling and electro-cavitation. Combing experimental, theoretical and computational methods, the initiation, evolution and transition of these instabilities are analyzed. To apply these dynamic surface instabilities to serving engineering and biology, new techniques of Dynamic Electrostatic Lithography and electroactive anti-biofouling are demonstrated.

  12. Magnetohydrodynamic process in solar activity

    Directory of Open Access Journals (Sweden)

    Jingxiu Wang

    2014-01-01

    Full Text Available Magnetohydrodynamics is one of the major disciplines in solar physics. Vigorous magnetohydrodynamic process is taking place in the solar convection zone and atmosphere. It controls the generating and structuring of the solar magnetic fields, causes the accumulation of magnetic non-potential energy in the solar atmosphere and triggers the explosive magnetic energy release, manifested as violent solar flares and coronal mass ejections. Nowadays detailed observations in solar astrophysics from space and on the ground urge a great need for the studies of magnetohydrodynamics and plasma physics to achieve better understanding of the mechanism or mechanisms of solar activity. On the other hand, the spectacular solar activity always serves as a great laboratory of magnetohydrodynamics. In this article, we reviewed a few key unresolved problems in solar activity studies and discussed the relevant issues in solar magnetohydrodynamics.

  13. Photochemical Transformation Processes in Sunlit Surface Waters

    Science.gov (United States)

    Vione, D.

    2012-12-01

    Photochemical reactions are major processes in the transformation of hardly biodegradable xenobiotics in surface waters. They are usually classified into direct photolysis and indirect or sensitised degradation. Direct photolysis requires xenobiotic compounds to absorb sunlight, and to get transformed as a consequence. Sensitised transformation involves reaction with transient species (e.g. °OH, CO3-°, 1O2 and triplet states of chromophoric dissolved organic matter, 3CDOM*), photogenerated by so-called photosensitisers (nitrate, nitrite and CDOM). CDOM is a major photosensitiser: is it on average the main source of °OH (and of CO3-° as a consequence, which is mainly produced upon oxidation by °OH of carbonate and bicarbonate) and the only important source of 1O2 and 3CDOM* [1, 2]. CDOM origin plays a key role in sensitised processes: allochthonous CDOM derived from soil runoff and rich in fulvic and humic substances is usually more photoactive than autochthonous CDOM (produced by in-water biological processes and mainly consisting of protein-like material) or of CDOM derived from atmospheric deposition. An interesting gradual evolution of CDOM origin and photochemistry can be found in mountain lakes across the treeline, which afford a gradual transition of allochthonous- autochtonous - atmopheric CDOM when passing from trees to alpine meadows to exposed rocks [3]. Another important issue is the sites of reactive species photoproduction in CDOM. While there is evidence that smaller molecular weight fractions are more photoactive, some studies have reported considerable 1O2 reactivity in CDOM hydrophobic sites and inside particles [4]. We have recently addressed the problem and found that dissolved species in standard humic acids (hydrodynamic diameter pollutants to be assessed and modelled. For instance, it is possible to predict pollutant half-life times by knowing absorption spectrum, direct photolysis quantum yield and reaction rate constants with °OH, CO3

  14. Response surface optimisation for activation of bentonite with microwave irradiation

    Directory of Open Access Journals (Sweden)

    Rožić Ljiljana S.

    2011-01-01

    Full Text Available In this study, the statistical design of the experimental method was applied on the acid activation process of bentonite with microwave irradiation. The influence of activation parameters (time, acid normality and microwave heating power on the selected process response of the activated bentonite samples was studied. The specific surface area was chosen for the process response, because the chemical, surface and structural properties of the activated clay determine and limit its potential applications. The relationship of various process parameters with the specific surface area of bentonite was examined. A mathematical model was developed using a second-order response surface model (RSM with a central composite design incorporating the above mentioned process parameters. The mathematical model developed helped in predicting the variation in specific surface area of activated bentonite with time (5-21 min, acid normality (2-7 N and microwave heating power (63-172 W. The calculated regression models were found to be statistically significant at the required range and presented little variability. Furthermore, high values of R2 (0.957 and R2 (adjusted (0.914 indicate a high dependence and correlation between the observed and the predicted values of the response. These high values also indicate that about 96% of the result of the total variation can be explained by this model. In addition, the model shows that increasing the time and acid normality improves the textural properties of bentonites, resulting in increased specific surface area. This model also can be useful for setting an optimum value of the activation parameters for achieving the maximum specific surface area. An optimum specific surface area of 142 m2g-1 was achieved with an acid normality of 5.2 N, activation time of 7.38 min and microwave power of 117 W. Acid activation of bentonite was found to occur faster with microwave irradiation than with conventional heating. Microwave

  15. Excimer laser surface modification: Process and properties

    Energy Technology Data Exchange (ETDEWEB)

    Jervis, T.R.; Nastasi, M. [Los Alamos National Lab., NM (United States); Hirvonen, J.P. [Technical Research Institute, Espoo (Finland). Metallurgy Lab.

    1992-12-01

    Surface modification can improve materials for structural, tribological, and corrosion applications. Excimer laser light has been shown to provide a rapid means of modifying surfaces through heat treating, surface zone refining, and mixing. Laser pulses at modest power levels can easily melt the surfaces of many materials. Mixing within the molten layer or with the gas ambient may occur, if thermodynamically allowed, followed by rapid solidification. The high temperatures allow the system to overcome kinetic barriers found in some ion mixing experiments. Alternatively, surface zone refinement may result from repeated melting-solidification cycles. Ultraviolet laser light couples energy efficiently to the surface of metallic and ceramic materials. The nature of the modification that follows depends on the properties of the surface and substrate materials. Alloying from both gas and predeposited layer sources has been observed in metals, semiconductors, and ceramics as has surface enrichment of Cr by zone refinement of stainless steel. Rapid solidification after melting often results in the formation of nonequilibrium phases, including amorphous materials. Improved surface properties, including tribology and corrosion resistance, are observed in these materials.

  16. Activation of interfacial enzymes at membrane surfaces

    DEFF Research Database (Denmark)

    Mouritsen, Ole G.; Andresen, Thomas Lars; Halperin, Avi

    2006-01-01

    A host of water-soluble enzymes are active at membrane surfaces and in association with membranes. Some of these enzymes are involved in signalling and in modification and remodelling of the membranes. A special class of enzymes, the phospholipases, and in particular secretory phospholipase A2 (s...

  17. Active processes in one dimension

    Science.gov (United States)

    Demaerel, Thibaut; Maes, Christian

    2018-03-01

    We consider the thermal and athermal overdamped motion of particles in one-dimensional geometries where discrete internal degrees of freedom (spin) are coupled with the translational motion. Adding a driving velocity that depends on the time-dependent spin constitutes the simplest model of active particles (run-and-tumble processes) where the violation of the equipartition principle and of the Sutherland-Einstein relation can be studied in detail even when there is generalized reversibility. We give an example (with four spin values) where the irreversibility of the translational motion manifests itself only in higher-order (than two) time correlations. We derive a generalized telegraph equation as the Smoluchowski equation for the spatial density for an arbitrary number of spin values. We also investigate the Arrhenius exponential law for run-and-tumble particles; due to their activity the slope of the potential becomes important in contrast to the passive diffusion case and activity enhances the escape from a potential well (if that slope is high enough). Finally, in the absence of a driving velocity, the presence of internal currents such as in the chemistry of molecular motors may be transmitted to the translational motion and the internal activity is crucial for the direction of the emerging spatial current.

  18. Surface active properties of lipid nanocapsules.

    Directory of Open Access Journals (Sweden)

    Celia R A Mouzouvi

    Full Text Available Lipid nanocapsules (LNCs are biomimetic nanocarriers used for the encapsulation of a broad variety of active ingredients. Similar to surface active compounds, LNCs contain both hydrophilic and hydrophobic parts in their structure. Moreover, the components of LNCs, macrogol 15 hydroxystearate (MHS and lecithin, are known for their surface active properties. Therefore, the aim of this paper was to investigate the capability of the LNCs to decrease surface tension using two techniques: drop tensiometry and the Wilhelmy plate method. LNCs with diameters ranging from 30 to 100 nm were successfully obtained using a phase inversion technique. The LNCs' properties, such as size and zeta potential, depend on the composition. LNCs exhibit a lower limiting surface tension compared to MHS (34.8-35.0 mN/m and 37.7-38.8 mN/m, respectively, as confirmed by both drop tensiometry and the Wilhelmy plate method. LNCs have exhibited a saturated interfacial concentration (SIC that was 10-fold higher than the critical micellar concentration (CMC of MHS or the SIC of binary and ternary mixtures of LNC ingredients. The SIC of the LNC formulations depended on the mass mixing ratio of the MHS/triglycerides but not on the presence of lecithin. The CMC/SIC values measured by the Wilhelmy plate method were higher than those obtained using drop tensiometry because of the longer duration of the tensiometry measurement. In conclusion, the surfactant-like properties of the LNCs offer new possibilities for medical and pharmaceutical applications.

  19. Active colloidal propulsion over a crystalline surface

    Science.gov (United States)

    Choudhury, Udit; Straube, Arthur V.; Fischer, Peer; Gibbs, John G.; Höfling, Felix

    2017-12-01

    We study both experimentally and theoretically the dynamics of chemically self-propelled Janus colloids moving atop a two-dimensional crystalline surface. The surface is a hexagonally close-packed monolayer of colloidal particles of the same size as the mobile one. The dynamics of the self-propelled colloid reflects the competition between hindered diffusion due to the periodic surface and enhanced diffusion due to active motion. Which contribution dominates depends on the propulsion strength, which can be systematically tuned by changing the concentration of a chemical fuel. The mean-square displacements (MSDs) obtained from the experiment exhibit enhanced diffusion at long lag times. Our experimental data are consistent with a Langevin model for the effectively two-dimensional translational motion of an active Brownian particle in a periodic potential, combining the confining effects of gravity and the crystalline surface with the free rotational diffusion of the colloid. Approximate analytical predictions are made for the MSD describing the crossover from free Brownian motion at short times to active diffusion at long times. The results are in semi-quantitative agreement with numerical results of a refined Langevin model that treats translational and rotational degrees of freedom on the same footing.

  20. Process of treating surfaces of metals

    International Nuclear Information System (INIS)

    Kimura, T.; Murao, A.; Kuwahara, T.

    1975-01-01

    Both higher corrosion resistance and paint adherence are given to films formed on the surfaces of metals by treating the surfaces with aqueous solutions of one or more materials selected from the group consisting of water soluble vinyl monomer or water soluble high polymer and then irradiating with ionizing radioactive rays on the nearly dried surface film. When a water soluble inorganic compound is mixed with the above mentioned aqueous solution, the film properties are greatly improved. The inorganic ionic material should contain a cation from the group consisting of Ca, Mg, Zn, Cr, Al, Fe, and Ni. Electron beams may be used. (U.S.)

  1. Diffusion processes in bombardment-induced surface topography

    International Nuclear Information System (INIS)

    Robinson, R.S.

    1984-01-01

    A treatment is given of the problem of surface diffusion processes occurring during surface topography development, whenever a surface is simultaneously seeded with impurities and ion bombarded. The development of controllable topography and the importance of surface diffusion parameters, which can be obtained during these studies, are also analyzed. 101 refs.; 7 figs.; 2 tabs

  2. Process optimization and insecticidal activity of alkaloids from the ...

    African Journals Online (AJOL)

    Process optimization and insecticidal activity of alkaloids from the root bark of Catalpa ovata G. Don by response surface methodology. ... Tropical Journal of Pharmaceutical Research. Journal Home · ABOUT THIS JOURNAL · Advanced ...

  3. Radiation processing activities at OGFL

    International Nuclear Information System (INIS)

    Sarkar, Atish

    2014-01-01

    CONCAST group of Industries has set up the first Radiation Processing Plant in Eastern India as 'VIKIRAN' named as Organic Green Foods Ltd., situated at Dankuni (Durgapur Highway Express) 25 km away from central Kolkata on August 21, 2004. Shri Sanjay Sureka, Managing Director of Organic Green Foods Ltd., Kolkata belongs to the famous CONCAST Group of Industries operates the largest plant of West Bengal engaged in manufacturing of Steel Industry. The facility was aimed at improving the quality of healthcare products and devices as well as Laboratory, Spice, Herbal and Ayurvedic Products of large volumes on an industrial scale. The operation of VIKIRAN for the last ten years, has unambiguously proved that both the above objectives have been fully met and now radiation sterilization has emerged as an efficient and effective industrial process. The irradiator is a panoramic wet storage class-IV type. This Facility is designed for 1000 KCi activity of source and is suitable in medium and high dose range application. VIKIRAN offers radiation sterilization service to more than 100 manufacturers

  4. Surface activation of dyed fabric for cellulase treatment.

    Science.gov (United States)

    Schimper, Christian B; Ibanescu, Constanta; Bechtold, Thomas

    2011-10-01

    Surface activation of fabric made from cellulose fibres, such as viscose, lyocell, modal fibres and cotton, can be achieved by printing of a concentrated NaOH-containing paste. From the concentration of reducing sugars formed in solution, an increase in intensity of the cellulase hydrolysis by a factor of six to eight was observed, which was mainly concentrated at the activated parts of the fabric surface. This method of local activation is of particular interest for modification of materials that have been dyed with special processes to attain an uneven distribution of dyestuff within the yarn cross-section, e.g., indigo ring-dyed denim yarn for jeans production. Fabrics made from regenerated cellulose fibres were used as model substrate to express the effects of surface activation on indigo-dyed material. Wash-down experiments on indigo-dyed denim demonstrated significant colour removal from the activated surface at low overall weight loss of 4-5%. The method is of relevance for a more eco-friendly processing of jeans in the garment industry. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Mineralogy of the Martian Surface: Crustal Composition to Surface Processes

    Science.gov (United States)

    Mustard, John F.

    1999-01-01

    Over the course of this award we have: 1) Completed and published the results of a study of the effects of hyperfine particles on reflectance spectra of olivine and quartz, which included the development of scattering codes. Research has also progressed in the analysis of the effects of fine particle sizes on clay spectra. 2) Completed the analysis of the mineralogy of dark regions, showed the insitu compositions are highly correlated to the SNC meteorites, and determined that the martian mantle was depleted in aluminum prior to 2-3 GA ago; Studies of the mineralogic heterogeneity of surficial materials on Mars have also been conducted. and 3) Performed initial work on the study of the physical and chemical processes likely to form and modify duricrust. This includes assessments of erosion rates, solubility and transport of iron in soil environments, and models of pedogenic crust formation.

  6. Thermal Diffusion Processes in Metal-Tip-Surface Interactions: Contact Formation and Adatom Mobility

    DEFF Research Database (Denmark)

    Sørensen, Mads Reinholdt; Jacobsen, Karsten Wedel; Jonsson, Hannes

    1996-01-01

    and the surface can occur by a sequence of atomic hop and exchange processes which become active on a millisecond time scale when the tip is about 3-5 Angstrom from the surface. Adatoms on the surface are stabilized by the presence of the tip and energy barriers for diffusion processes in the region under the tip......We have carried out computer simulations to identify and characterize various thermally activated atomic scale processes that can play an important role in room temperature experiments where a metal tip is brought close to a metal surface. We find that contact formation between the tip...

  7. Surface processing: existing and potential applications of ultraviolet light.

    Science.gov (United States)

    Manzocco, Lara; Nicoli, Maria Cristina

    2015-01-01

    Solid foods represent optimal matrices for ultraviolet processing with effects well beyond nonthermal surface disinfection. UV radiation favors hormetic response in plant tissues and degradation of toxic compound on the product surface. Photoinduced reactions can also provide unexplored possibilities to steer structure and functionality of food biopolymers. The possibility to extensively exploit this technology will depend on availability of robust information about efficacious processing conditions and adequate strategies to completely and homogeneously process food surface.

  8. Mechanochemical activation and gallium and indiaarsenides surface catalycity

    Science.gov (United States)

    Kirovskaya, I. A.; Mironova, E. V.; Umansky, I. V.; Brueva, O. Yu; Murashova, A. O.; Yureva, A. V.

    2018-01-01

    The present work has been carried out in terms of determining the possibilities for a clearer identification of the active sites nature, intermediate surface compounds nature, functional groups during adsorption and catalysis, activation of the diamond-like semiconductors surface (in particular, the AIIIBV type) based on mechanochemical studies of the “reaction medium (H2O, iso-C3H7OH) - dispersible semiconductor (GaAs, InAs)” systems. As a result, according to the read kinetic curves of dispersion in water, both acidification and alkalinization of the medium have been established and explained; increased activity of the newly formed surface has been noted; intermediate surface compounds, functional groups appearing on the real surface and under H2O adsorption conditions, adsorption and catalytic decomposition of iso-C3H7OH have been found (with explanation of the origin). The unconcealed role of coordinatively unsaturated atoms as active sites of these processes has been shown; the relative catalytic activity of the semiconductors studied has been evaluated. Practical recommendations on the preferred use of gallium arsenide in semiconductor gas analysis and semiconductor catalysis have been given in literature searches, great care should be taken in constructing both.

  9. UMTRA Surface Project management action process document: Final. Revision 2

    International Nuclear Information System (INIS)

    1996-06-01

    Title 1 of the UMTRCA authorized the DOE to undertake remedial actions at these designed sites and associated vicinity properties (VP), which contain uranium mill tailings and other residual radioactive materials (RRM) derived from the processing sites. Title 2 of the UMTRCA addresses uranium mill sites that were licensed at the time the UMTRCA was enacted. Cleanup of these Title 2 sites is the responsibility of the licensees. The cleanup of the Title 1 sites has been split into two separate projects: the Surface Project, which deals with the mill buildings, tailings, and contaminated soils at the sites and VPs; and the Ground Water Project, which is limited to the contaminated ground water at the sites. This management action process (MAP) document discusses the Uranium Mill Tailings Remedial Action (UMTRA) Surface Project. Since its inception through March 1996, the Surface Project (hereinafter called the Project) has cleaned up 16 of the 24 designated processing sites and approximately 5,000 VPs, reducing the risk to human health and the environment posed by the uranium mill tailings. Two of the 24 sites, Belfield and Bowman, North Dakota, will not be remediated at the request of the state, reducing the total number of sites to 22. By the start of FY1998, the remaining 6 processing sites and associated VPs will be cleaned up. The remedial action activities to be funded in FY1998 by the FY1998 budget request are remediation of the remaining Grand Junction, Colorado, VPs; closure of the Cheney disposal cell in Grand Junction, Colorado; and preparation of the completion reports for 4 completed sites

  10. UMTRA Surface Project management action process document: Final. Revision 2

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-06-01

    Title 1 of the UMTRCA authorized the DOE to undertake remedial actions at these designed sites and associated vicinity properties (VP), which contain uranium mill tailings and other residual radioactive materials (RRM) derived from the processing sites. Title 2 of the UMTRCA addresses uranium mill sites that were licensed at the time the UMTRCA was enacted. Cleanup of these Title 2 sites is the responsibility of the licensees. The cleanup of the Title 1 sites has been split into two separate projects: the Surface Project, which deals with the mill buildings, tailings, and contaminated soils at the sites and VPs; and the Ground Water Project, which is limited to the contaminated ground water at the sites. This management action process (MAP) document discusses the Uranium Mill Tailings Remedial Action (UMTRA) Surface Project. Since its inception through March 1996, the Surface Project (hereinafter called the Project) has cleaned up 16 of the 24 designated processing sites and approximately 5,000 VPs, reducing the risk to human health and the environment posed by the uranium mill tailings. Two of the 24 sites, Belfield and Bowman, North Dakota, will not be remediated at the request of the state, reducing the total number of sites to 22. By the start of FY1998, the remaining 6 processing sites and associated VPs will be cleaned up. The remedial action activities to be funded in FY1998 by the FY1998 budget request are remediation of the remaining Grand Junction, Colorado, VPs; closure of the Cheney disposal cell in Grand Junction, Colorado; and preparation of the completion reports for 4 completed sites.

  11. Zerodur polishing process for high surface quality and high efficiency

    International Nuclear Information System (INIS)

    Tesar, A.; Fuchs, B.

    1992-08-01

    Zerodur is a glass-ceramic composite importance in applications where temperature instabilities influence optical and mechanical performance, such as in earthbound and spaceborne telescope mirror substrates. Polished Zerodur surfaces of high quality have been required for laser gyro mirrors. Polished surface quality of substrates affects performance of high reflection coatings. Thus, the interest in improving Zerodur polished surface quality has become more general. Beyond eliminating subsurface damage, high quality surfaces are produced by reducing the amount of hydrated material redeposited on the surface during polishing. With the proper control of polishing parameters, such surfaces exhibit roughnesses of < l Angstrom rms. Zerodur polishing was studied to recommend a high surface quality polishing process which could be easily adapted to standard planetary continuous polishing machines and spindles. This summary contains information on a polishing process developed at LLNL which reproducibly provides high quality polished Zerodur surfaces at very high polishing efficiencies

  12. Effect of surface wettability caused by radiation induced surface activation on leidenfrost condition

    International Nuclear Information System (INIS)

    Takamasa, T.; Hazuku, T.; Tamura, N.; Okamoto, K.; Mishima, K.; Furuya, M.

    2003-01-01

    Improving the limit of boiling heat transfer or critical heat flux requires that the cooling liquid can contact the heating surface, or a high-wettability, highly hydrophilic heating surface, even if a vapor bubble layer is generated on the surface. From this basis, we investigated surface wettability and Leidenfrost condition using metal oxides irradiated by γ-rays. In our previous study, contact angle, an indicator of macroscopic wettability, of a water droplet on metal oxide at room temperature was measured by image processing of the images obtained by a CCD video camera. The results showed that the surface wettability on metal oxide pieces of titanium, Zircaloy No. 4, SUS-304, and copper was improved significantly by the Radiation Induced Surface Activation (RISA) phenomenon. To delineate the effect of Radiation Induced Surface Activation (RISA) on heat transferring phenomena, the Leidenfrost condition and quenching of metal oxides irradiated by γ-rays were investigated. In the Leidenfrost experiment, when the temperature of the heating surface reached the wetting limit temperature, water-solid contact vanished because a stable vapor film existed between the droplet and the metal surface; i.e., a Leidenfrost condition obtained. The wetting limit temperature increased with integrated irradiation dose. After irradiation, the wet length and the duration of contact increased, and the contact angle decreased. In the quenching test, high surface wettability, or a highly hydrophilic condition, of a simulated fuel rod made of SUS was achieved, and the quenching velocities were increased up to 20-30% after 300 kGy 60Co γ-ray irradiation

  13. Effect of surface wettability caused by radiation induced surface activation on leidenfrost condition

    Energy Technology Data Exchange (ETDEWEB)

    Takamasa, T.; Hazuku, T.; Tamura, N.; Okamoto, K. [Tokyo Univ., Tokyo (Japan); Mishima, K. [Kyoto Univ., Kyoto (Japan); Furuya, M. [Central Research Institute of Electric Power Industry, Tokyo (Japan)

    2003-07-01

    Improving the limit of boiling heat transfer or critical heat flux requires that the cooling liquid can contact the heating surface, or a high-wettability, highly hydrophilic heating surface, even if a vapor bubble layer is generated on the surface. From this basis, we investigated surface wettability and Leidenfrost condition using metal oxides irradiated by {gamma}-rays. In our previous study, contact angle, an indicator of macroscopic wettability, of a water droplet on metal oxide at room temperature was measured by image processing of the images obtained by a CCD video camera. The results showed that the surface wettability on metal oxide pieces of titanium, Zircaloy No. 4, SUS-304, and copper was improved significantly by the Radiation Induced Surface Activation (RISA) phenomenon. To delineate the effect of Radiation Induced Surface Activation (RISA) on heat transferring phenomena, the Leidenfrost condition and quenching of metal oxides irradiated by {gamma}-rays were investigated. In the Leidenfrost experiment, when the temperature of the heating surface reached the wetting limit temperature, water-solid contact vanished because a stable vapor film existed between the droplet and the metal surface; i.e., a Leidenfrost condition obtained. The wetting limit temperature increased with integrated irradiation dose. After irradiation, the wet length and the duration of contact increased, and the contact angle decreased. In the quenching test, high surface wettability, or a highly hydrophilic condition, of a simulated fuel rod made of SUS was achieved, and the quenching velocities were increased up to 20-30% after 300 kGy 60Co {gamma}-ray irradiation.

  14. Auger processes in ion-surface collisions

    International Nuclear Information System (INIS)

    Zampieri, Guillermo.

    1985-01-01

    Bombardment of solid targets with low-energy noble gas ions can produce Auger electron emission from the target atoms and/or from the projectiles. In the case of Auger emission from the projectile, Auger emission was observed during the bombardment of Na, Mg, Al and Si with Ne + ions. This emission was studied as a function of the energy, incidence angle and charge state of the projectile. From the analysis, it is concluded that the emission originates in the decay in vacuum of excited and reflected Ne atoms, moving outside the surface. Auger emission was not observed during the bombardment of K, V and Ni with Ar + ions; Zr and Cs with Kr + , and Xe + ions, respectively; and Li and Be with He + ions. In the case of Auger emission from the target, studies of certain aspects of the Na, Mg and Al Auger electron emission spectra were made. The results allow to identify two components in the Auger feature, coresponding to two kinds of Auger transition. The total spectra results from the superposition of both kinds of emission. Auger spectra from K obtained during Ar + and K + bombardment of K-implanted Be, Mg, Al and Cu were also analyzed. Similar to the Na, Mg and Al Auger spectra, the K Auger feature is composed of an atomic like peak superimposed on a bandlike structure. Both components correspond to Auger transitions in K atoms with a 3p vacancy, occuring in vacuum and inside the solid, respectively. (M.E.L.) [es

  15. Rubber friction and force transmission during the shearing process of actively-driven vacuum grippers on rough surfaces; Elastomerreibung und Kraftuebertragung beim Abscheren von aktiv betriebenen Vakuumgreifern auf rauen Oberflaechen

    Energy Technology Data Exchange (ETDEWEB)

    Kern, Patrick

    2016-12-21

    Nowadays, vacuum grippers come in many different shapes and sizes. Their stability is guaranteed through specially manufactured metal fittings. These fittings are non-positively and positively connected to the elastic part of the vacuum gripper. The design of the elastic part may vary, though. Elastomer components are used to ensure tightness for the negative pressure in the active cave chamber of the vacuum gripper, as well as for the transfer of shearing forces, which acting parallel to the surface. Some vacuum grippers feature one elastomer for both the sealing function and the transfer of shear forces; other gripper types are equipped with various elastomers for those applications. The vacuum grippers described in this work are equipped with structured rubber friction pads, their tightness being ensured by sealing lips made of a flexible foam rubber. A restraint system consisting of one or several vacuum grippers must be sized prior to its actual practical use. For the transmission of shearing forces, which acting parallel to the surface, it is necessary to take the tribological system, consisting of the suction element's elastomer and the base material, into account since these loads put shearing stress on the vacuum gripper. In practice, however, a standardized value is given for the coefficient of friction μ; i.e. the ratio of transmissible frictional force to the normal force. This does neither include a detailed description of the elastomer used nor of the roughness of the base material. The standardized friction coefficients cannot be applied to the practical design of restraint systems. The present work includes the analysis of the load transmission and the modeling of the friction coefficients μ on rough surfaces during the shearing process of actively-driven vacuum grippers. Based on current theories, the phenomenon of elastomeric friction can be attributed to the two main components of hysteresis and adhesion friction. Both components are

  16. Surface and Adsorption Properties of Activated Carbon Fabric Prepared from Cellulosic Polymer: Mixed Activation Method

    Energy Technology Data Exchange (ETDEWEB)

    Bhati, Surendra; Mahur, J. S.; Choubey, O. N. [Barkatullah Univ., Bhopal (India); Dixit, Mahur Savita [Maulana Azad National Institute of Technology, Bhopla (India)

    2013-02-15

    In this study, activated carbon fabric was prepared from a cellulose-based polymer (viscose rayon) via a combination of physical and chemical activation (mixed activation) processes by means of CO{sub 2} as a gasifying agent and surface and adsorption properties were evaluated. Experiments were performed to investigate the consequence of activation temperature (750, 800, 850 and 925 .deg. C), activation time (15, 30, 45 and 60 minutes) and CO{sub 2} flow rate (100, 200, 300 and 400 mL/min) on the surface and adsorption properties of ACF. The nitrogen adsorption isotherm at 77 K was measured and used for the determination of surface area, total pore volume, micropore volume, mesopore volume and pore size distribution using BET, t-plot, DR, BJH and DFT methods, respectively. It was observed that BET surface area and TPV increase with rising activation temperature and time due to the formation of new pores and the alteration of micropores into mesopores. It was also found that activation temperature dominantly affects the surface properties of ACF. The adsorption of iodine and CCl{sub 4} onto ACF was investigated and both were found to correlate with surface area.

  17. Surface and Adsorption Properties of Activated Carbon Fabric Prepared from Cellulosic Polymer: Mixed Activation Method

    International Nuclear Information System (INIS)

    Bhati, Surendra; Mahur, J. S.; Choubey, O. N.; Dixit, Mahur Savita

    2013-01-01

    In this study, activated carbon fabric was prepared from a cellulose-based polymer (viscose rayon) via a combination of physical and chemical activation (mixed activation) processes by means of CO 2 as a gasifying agent and surface and adsorption properties were evaluated. Experiments were performed to investigate the consequence of activation temperature (750, 800, 850 and 925 .deg. C), activation time (15, 30, 45 and 60 minutes) and CO 2 flow rate (100, 200, 300 and 400 mL/min) on the surface and adsorption properties of ACF. The nitrogen adsorption isotherm at 77 K was measured and used for the determination of surface area, total pore volume, micropore volume, mesopore volume and pore size distribution using BET, t-plot, DR, BJH and DFT methods, respectively. It was observed that BET surface area and TPV increase with rising activation temperature and time due to the formation of new pores and the alteration of micropores into mesopores. It was also found that activation temperature dominantly affects the surface properties of ACF. The adsorption of iodine and CCl 4 onto ACF was investigated and both were found to correlate with surface area

  18. Coordinated surface activities in Variovorax paradoxus EPS

    Directory of Open Access Journals (Sweden)

    Gregory Glenn A

    2009-06-01

    Full Text Available Abstract Background Variovorax paradoxus is an aerobic soil bacterium frequently associated with important biodegradative processes in nature. Our group has cultivated a mucoid strain of Variovorax paradoxus for study as a model of bacterial development and response to environmental conditions. Colonies of this organism vary widely in appearance depending on agar plate type. Results Surface motility was observed on minimal defined agar plates with 0.5% agarose, similar in nature to swarming motility identified in Pseudomonas aeruginosa PAO1. We examined this motility under several culture conditions, including inhibition of flagellar motility using Congo Red. We demonstrated that the presence of a wetting agent, mineral, and nutrient content of the media altered the swarming phenotype. We also demonstrated that the wetting agent reduces the surface tension of the agar. We were able to directly observe the presence of the wetting agent in the presence and absence of Congo Red, and found that incubation in a humidified chamber inhibited the production of wetting agent, and also slowed the progression of the swarming colony. We observed that swarming was related to both carbon and nitrogen sources, as well as mineral salts base. The phosphate concentration of the mineral base was critical for growth and swarming on glucose, but not succinate. Swarming on other carbon sources was generally only observed using M9 salts mineral base. Rapid swarming was observed on malic acid, d-sorbitol, casamino acids, and succinate. Swarming at a lower but still detectable rate was observed on glucose and sucrose, with weak swarming on maltose. Nitrogen source tests using succinate as carbon source demonstrated two distinct forms of swarming, with very different macroscopic swarm characteristics. Rapid swarming was observed when ammonium ion was provided as nitrogen source, as well as when histidine, tryptophan, or glycine was provided. Slower swarming was observed

  19. Anticipated Activities in Maritime Work, Process Control, and Business Processes

    DEFF Research Database (Denmark)

    Andersen, Peter Bøgh

    2004-01-01

    Most activities are anticipated before they are executed. The paper presents methods for describing this anticipated state and the processes that may lead to a new state where the activities are executed. The method builds on linguistic case-theory.......Most activities are anticipated before they are executed. The paper presents methods for describing this anticipated state and the processes that may lead to a new state where the activities are executed. The method builds on linguistic case-theory....

  20. Exotic high activity surface patterns in PtAu nanoclusters

    KAUST Repository

    Mokkath, Junais Habeeb; Schwingenschlö gl, Udo

    2013-01-01

    of the truncated octahedron cluster motif. Exotic surface patterns are obtained particularly for Pt-rich compositions, where Pt atoms are being surrounded by Au atoms. These surface arrangements boost the catalytic activity by creating a large number of active

  1. Superhydrophobic coatings for aluminium surfaces synthesized by chemical etching process

    Directory of Open Access Journals (Sweden)

    Priya Varshney

    2016-10-01

    Full Text Available In this paper, the superhydrophobic coatings on aluminium surfaces were prepared by two-step (chemical etching followed by coating and one-step (chemical etching and coating in a single step processes using potassium hydroxide and lauric acid. Besides, surface immersion time in solutions was varied in both processes. Wettability and surface morphologies of treated aluminium surfaces were characterized using contact angle measurement technique and scanning electron microscopy, respectively. Microstructures are formed on the treated aluminium surfaces which lead to increase in contact angle of the surface (>150°. Also on increasing immersion time, contact angle further increases due to increase in size and depth of microstructures. Additionally, these superhydrophobic coatings show excellent self-cleaning and corrosion-resistant behavior. Water jet impact, floatation on water surface, and low temperature condensation tests assert the excellent water-repellent nature of coatings. Further, coatings are to be found mechanically, thermally, and ultraviolet stable. Along with, these coatings are found to be excellent regeneration ability as verified experimentally. Although aforesaid both processes generate durable and regenerable superhydrophobic aluminium surfaces with excellent self-cleaning, corrosion-resistant, and water-repellent characteristics, but one-step process is proved more efficient and less time consuming than two-step process and promises to produce superhydrophobic coatings for industrial applications.

  2. Surface and interface electronic structure: Three year activity report

    International Nuclear Information System (INIS)

    Kevan, S.D.

    1992-01-01

    The 3-year activity report covers surface structure and phonon anomalies (surface reconstruction on W(001) and Mo(001), adsorbate lateral ordering, surface Fermi contours and phonon anomalies on Pt(111) and Pd(001)), adsorbate vibrational damping, charge transfer in momentum space: W(011)-K, surface states and resonances (relativistic effects ampersand computations, surface resonances)

  3. SURFACE CAST IRON STRENGTHENING USING COMBINED LASER AND ULTRASONIC PROCESSING

    Directory of Open Access Journals (Sweden)

    O. G. Devojno

    2013-01-01

    Full Text Available The paper provides an analysis of ultrasonic surface plastic deformation and subsequent laser thermal strengthening of gray cast iron parts in the regime of hardening from a solid state with the purpose to obtain strengthened surface layers of bigger depth and less roughness of the processed surface. Program complex ANSYS 11.0 has been used for calculation of temperature fields induced by laser exposure.  The appropriate regime of laser processing without surface fusion has been selected on the basis of the applied complex. The possibility of displacement in the bottom boundary of α–γ-transformation temperature  for СЧ20 with 900 °С up to 800 °С is confirmed due to preliminary ultrasonic surface plastic deformation of the surface that allows to expand technological opportunities of laser quenching  of gray  cast iron from a solid state. 

  4. Modification of polymer surfaces to enhance enzyme activity and stability

    DEFF Research Database (Denmark)

    Hoffmann, Christian

    Enzyme immobilization is an important concept for the development of improved biocatalytic processes, primarily through facilitated separation procedures. However, enzyme immobilization usually comes at a price of reduced biocatalytic activity. For this reason, different immobilization methods have...... already been developed, combining the same goal to improve enzyme activity, stability and selectivity. Polymer materials have shown, due to their easy processibility and versatile properties, high potential as enzyme support. However, in order to achieve improved enzyme performance, the combination...... on their tailored surface modification in order to obtain improved enzyme-support systems. Firstly, an off-stoichiometric thiol-ene (OSTE) thermosetting material was used for the development of a screening platform allowing the investigation of micro-environmental effects and their impact on the activity...

  5. Homogeneous near surface activity distribution by double energy activation for TLA

    International Nuclear Information System (INIS)

    Takacs, S.; Ditroi, F.; Tarkanyi, F.

    2007-01-01

    Thin layer activation (TLA) is a versatile tool for activating thin surface layers in order to study real-time the surface loss by wear, corrosion or erosion processes of the activated parts, without disassembling or stopping running mechanical structures or equipment. The research problem is the determination of the irradiation parameters to produce point-like or large area optimal activity-depth distribution in the sample. Different activity-depth profiles can be produced depending on the type of the investigated material and the nuclear reaction used. To produce activity that is independent of the depth up to a certain depth is desirable when the material removed from the surface by wear, corrosion or erosion can be collected completely. By applying dual energy irradiation the thickness of this quasi-constant activity layer can be increased or the deviation of the activity distribution from a constant value can be minimized. In the main, parts made of metals and alloys are suitable for direct activation, but by using secondary particle implantation the wear of other materials can also be studied in a surface range a few micrometers thick. In most practical cases activation of a point-like spot (several mm 2 ) is enough to monitor the wear, corrosion or erosion, but for special problems relatively large surfaces areas of complicated spatial geometry need to be activated uniformly. Two ways are available for fulfilling this task, (1) production of large area beam spot or scanning the beam over the surface in question from the accelerator side, or (2) a programmed 3D movement of the sample from the target side. Taking into account the large variability of tasks occurring in practice, the latter method was chosen as the routine solution in our cyclotron laboratory

  6. Diffusion processes in bombardment-induced surface topography

    International Nuclear Information System (INIS)

    Robinson, R.S.

    1984-01-01

    The bombardment of surfaces with moderate energy ions can lead to the development of various micron-sized surface structures. These structures include ridges, ledges, flat planes, pits and cones. The causal phenomena in the production of these features are sputtering, ion reflection, redeposition of sputtered material, and surface diffusion of both impurity and target-atom species. The authors concentrate on the formation of ion bombardment-induced surface topography wherein surface diffusion is a dominant process. The most thoroughly understood aspect of this topography development is the generation of cone-like structures during sputtering. The formation of cones during sputtering has been attributed to three effects. These are: (1) the presence of asperities, defects, or micro-inclusions in the surface layers, (2) the presence of impurities on the surfaces, and (3) particular crystal orientations. (Auth.)

  7. Decommissioning alternatives, process and work activities

    International Nuclear Information System (INIS)

    Anon.

    1986-01-01

    The following outlines the topics discussed under Decommissioning Alternatives, Process and Work Activities: (1) decommissioning alternatives, (2) work activities for prompt removal/dismantling, (3) work activities for entombment with delayed dismantling, and (4) work activities for mothballing with delayed dismantling

  8. Apparatus and process for the surface treatment of carbon fibers

    Science.gov (United States)

    Paulauskas, Felix Leonard; Ozcan, Soydan; Naskar, Amit K.

    2016-05-17

    A method for surface treating a carbon-containing material in which carbon-containing material is reacted with decomposing ozone in a reactor (e.g., a hollow tube reactor), wherein a concentration of ozone is maintained throughout the reactor by appropriate selection of at least processing temperature, gas stream flow rate, reactor dimensions, ozone concentration entering the reactor, and position of one or more ozone inlets (ports) in the reactor, wherein the method produces a surface-oxidized carbon or carbon-containing material, preferably having a surface atomic oxygen content of at least 15%. The resulting surface-oxidized carbon material and solid composites made therefrom are also described.

  9. Activating clinical trials: a process improvement approach.

    Science.gov (United States)

    Martinez, Diego A; Tsalatsanis, Athanasios; Yalcin, Ali; Zayas-Castro, José L; Djulbegovic, Benjamin

    2016-02-24

    The administrative process associated with clinical trial activation has been criticized as costly, complex, and time-consuming. Prior research has concentrated on identifying administrative barriers and proposing various solutions to reduce activation time, and consequently associated costs. Here, we expand on previous research by incorporating social network analysis and discrete-event simulation to support process improvement decision-making. We searched for all operational data associated with the administrative process of activating industry-sponsored clinical trials at the Office of Clinical Research of the University of South Florida in Tampa, Florida. We limited the search to those trials initiated and activated between July 2011 and June 2012. We described the process using value stream mapping, studied the interactions of the various process participants using social network analysis, and modeled potential process modifications using discrete-event simulation. The administrative process comprised 5 sub-processes, 30 activities, 11 decision points, 5 loops, and 8 participants. The mean activation time was 76.6 days. Rate-limiting sub-processes were those of contract and budget development. Key participants during contract and budget development were the Office of Clinical Research, sponsors, and the principal investigator. Simulation results indicate that slight increments on the number of trials, arriving to the Office of Clinical Research, would increase activation time by 11 %. Also, incrementing the efficiency of contract and budget development would reduce the activation time by 28 %. Finally, better synchronization between contract and budget development would reduce time spent on batching documentation; however, no improvements would be attained in total activation time. The presented process improvement analytic framework not only identifies administrative barriers, but also helps to devise and evaluate potential improvement scenarios. The strength

  10. An investigation of laser processing of silica surfaces

    International Nuclear Information System (INIS)

    Weber, A.J.; Stewart, A.F.; Exarhos, G.J.; Stowell, W.K.

    1988-01-01

    An initial set of experiments has been conducted to determine the practicality of laser processing of optical substrates. In contrast to earlier work, a high average power CO 2 laser was used to flood load the entire surface of each test sample. Fused silica substrates were laser polished on both surfaces at power densities ranging from 150 to 350 W/cm 2 . During each test sequence sample surface temperatures were recorded using a thermal imaging system. Extensive pre- and post-test characterization revealed that surface roughness and scattering of bare silica surfaces were reduced while internal stress increased. Laser damage thresholds were found to increase only for certain conditions. Changes in the microstructure were observed. These preliminary experiments demonstrate that laser processing can dramatically improve the optical properties of fused silica substrates

  11. Direct instrumental identification of catalytically active surface sites

    Science.gov (United States)

    Pfisterer, Jonas H. K.; Liang, Yunchang; Schneider, Oliver; Bandarenka, Aliaksandr S.

    2017-09-01

    The activity of heterogeneous catalysts—which are involved in some 80 per cent of processes in the chemical and energy industries—is determined by the electronic structure of specific surface sites that offer optimal binding of reaction intermediates. Directly identifying and monitoring these sites during a reaction should therefore provide insight that might aid the targeted development of heterogeneous catalysts and electrocatalysts (those that participate in electrochemical reactions) for practical applications. The invention of the scanning tunnelling microscope (STM) and the electrochemical STM promised to deliver such imaging capabilities, and both have indeed contributed greatly to our atomistic understanding of heterogeneous catalysis. But although the STM has been used to probe and initiate surface reactions, and has even enabled local measurements of reactivity in some systems, it is not generally thought to be suited to the direct identification of catalytically active surface sites under reaction conditions. Here we demonstrate, however, that common STMs can readily map the catalytic activity of surfaces with high spatial resolution: we show that by monitoring relative changes in the tunnelling current noise, active sites can be distinguished in an almost quantitative fashion according to their ability to catalyse the hydrogen-evolution reaction or the oxygen-reduction reaction. These data allow us to evaluate directly the importance and relative contribution to overall catalyst activity of different defects and sites at the boundaries between two materials. With its ability to deliver such information and its ready applicability to different systems, we anticipate that our method will aid the rational design of heterogeneous catalysts.

  12. Process for integrating surface drainage constraints on mine planning

    Energy Technology Data Exchange (ETDEWEB)

    Sawatsky, L.F; Ade, F.L.; McDonald, D.M.; Pullman, B.J. [Golder Associates Ltd., Calgary, AB (Canada)

    2009-07-01

    Surface drainage for mine closures must be considered during all phases of mine planning and design in order to minimize environmental impacts and reduce costs. This paper discussed methods of integrating mine drainage criteria and associated mine planning constraints into the mine planning process. Drainage constraints included stream diversions; fish compensation channels; collection receptacles for the re-use of process water; separation of closed circuit water from fresh water; and the provision of storage ponds. The geomorphic approach replicated the ability of natural channels to respond to local and regional changes in hydrology as well as channel disturbances from extreme flood events, sedimentation, debris, ice jams, and beaver activity. The approach was designed to enable a sustainable system and provide conveyance capacity for extreme floods without spillage to adjacent watersheds. Channel dimensions, bank and bed materials, sediment loads, bed material supplies and the hydrologic conditions of the analogue stream were considered. Hydrologic analyses were conducted to determine design flood flow. Channel routes, valley slopes, sinuosity, width, and depth were established. It was concluded that by incorporating the geomorphic technique, mine operators and designers can construct self-sustaining drainage systems that require little or no maintenance in the long-term. 7 refs.

  13. Plasma nitriding - an eco friendly surface hardening process

    International Nuclear Information System (INIS)

    Mukherjee, S.

    2015-01-01

    Surface hardening is a process of heating the metal such that the surface gets only hardened. This process is adopted for many components like gears, cams, and crankshafts, which desire high hardness on the outer surface with a softer core to withstand the shocks. So, to attain such properties processes like carburising, nitriding, flame hardening and induction hardening are employed. Amongst these processes nitriding is the most commonly used process by many industries. In nitriding process the steel material is heated to a temperature of around 550 C and then exposed to atomic nitrogen. This atomic nitrogen reacts with iron and other alloying elements and forms nitrides, which are very hard in nature. By this process both wear resistance and hardness of the product can be increased. The atomic nitrogen required for this process can be obtained using ammonia gas (gas nitriding), cyanide based salt bath (liquid nitriding) and plasma medium (plasma nitriding). However, plasma nitriding has recently received considerable industrial interest owing to its characteristic of faster nitrogen penetration, short treatment time, low process temperature, minimal distortion, low energy use and easier control of layer formation compared with conventional techniques such as gas and liquid nitriding. This process can be used for all ferrous materials including stainless steels. Plasma nitriding is carried out using a gas mixture of nitrogen and hydrogen gas at sub atmospheric pressures hence, making it eco-friendly in nature. Plasma nitriding allows modification of the surface layers and hardness profiles by changing the gas mixture and temperature. The wide applicable temperature range enables a multitude of applications, beyond the possibilities of gas or salt bath processes. This has led to numerous applications of this process in industries such as the manufacture of machine parts for plastics and food processing, packaging and tooling as well as pumps and hydraulic, machine

  14. Surface processing for bulk niobium superconducting radio frequency cavities

    Science.gov (United States)

    Kelly, M. P.; Reid, T.

    2017-04-01

    The majority of niobium cavities for superconducting particle accelerators continue to be fabricated from thin-walled (2-4 mm) polycrystalline niobium sheet and, as a final step, require material removal from the radio frequency (RF) surface in order to achieve performance needed for use as practical accelerator devices. More recently bulk niobium in the form of, single- or large-grain slices cut from an ingot has become a viable alternative for some cavity types. In both cases the so-called damaged layer must be chemically etched or electrochemically polished away. The methods for doing this date back at least four decades, however, vigorous empirical studies on real cavities and more fundamental studies on niobium samples at laboratories worldwide have led to seemingly modest improvements that, when taken together, constitute a substantial advance in the reproducibility for surface processing techniques and overall cavity performance. This article reviews the development of niobium cavity surface processing, and summarizes results of recent studies. We place some emphasis on practical details for real cavity processing systems which are difficult to find in the literature but are, nonetheless, crucial for achieving the good and reproducible cavity performance. New approaches for bulk niobium surface treatment which aim to reduce cost or increase performance, including alternate chemical recipes, barrel polishing and ‘nitrogen doping’ of the RF surface, continue to be pursued and are closely linked to the requirements for surface processing.

  15. Investigation of the change in CdxHg1-xTe surface chemical structure under processing in N2O and H2 gases activated by a high-frequency discharge

    International Nuclear Information System (INIS)

    Vasil'ev, V.V.; Zakhar'yash, T.I.; Kesler, V.G.; Parm, I.O.; Solov'ev, A.P.

    2001-01-01

    The change in Cd x Hg 1-x Te (CTM) surface chemical composition is investigated during the processing by atomic beams of oxygen and hydrogen, obtained by a method of the electronic impact in a high-frequency plasma (N 2 O and H 2 ). The analysis is carried out using methods of Auger electron spectroscopy and X-ray photoelectron spectroscopy. It is shown that consecutive treatment by beams of atomic oxygen and hydrogen results in removing from the sample surface as carbon impurities so a layer of as-grown oxide and metallic tellurium. It is concluded that the suggested technique of CTM substrate surface pretreatment can be used efficiently in manufacturing semiconductor junctions [ru

  16. Surface engineering of glazing materials and structures using plasma processes

    International Nuclear Information System (INIS)

    Anders, Andre; Monteiro, Othon R.

    2003-01-01

    A variety of coatings is commercially produced on a very large scale, including transparent conducting oxides and multi-layer silver-based low-emissivity and solar control coatings. A very brief review of materials and manufacturing process is presented and illustrated by ultrathin silver films and chevron copper films. Understanding the close relation between manufacturing processes and bulk and surface properties of materials is crucial for film growth and self-assembly processes

  17. Surface topography of parallel grinding process for nonaxisymmetric aspheric lens

    International Nuclear Information System (INIS)

    Zhang Ningning; Wang Zhenzhong; Pan Ri; Wang Chunjin; Guo Yinbiao

    2012-01-01

    Workpiece surface profile, texture and roughness can be predicted by modeling the topography of wheel surface and modeling kinematics of grinding process, which compose an important part of precision grinding process theory. Parallel grinding technology is an important method for nonaxisymmetric aspheric lens machining, but there is few report on relevant simulation. In this paper, a simulation method based on parallel grinding for precision machining of aspheric lens is proposed. The method combines modeling the random surface of wheel and modeling the single grain track based on arc wheel contact points. Then, a mathematical algorithm for surface topography is proposed and applied in conditions of different machining parameters. The consistence between the results of simulation and test proves that the algorithm is correct and efficient. (authors)

  18. Plasma assisted surface coating/modification processes: An emerging technology

    Science.gov (United States)

    Spalvins, T.

    1986-01-01

    A broad understanding of the numerous ion or plasma assisted surface coating/modification processes is sought. An awareness of the principles of these processes is needed before discussing in detail the ion nitriding technology. On the basis of surface modifications arising from ion or plasma energizing and interactions, it can be broadly classified as deposition of distinct overlay coatings (sputtering-dc, radio frequency, magnetron, reactive; ion plating-diode, triode) and surface property modification without forming a discrete coating (ion implantation, ion beam mixing, laser beam irradiation, ion nitriding, ion carburizing, plasma oxidation). These techniques offer a great flexibility and are capable in tailoring desirable chemical and structural surface properties independent of the bulk properties.

  19. Plasma assisted surface coating/modification processes - An emerging technology

    Science.gov (United States)

    Spalvins, T.

    1987-01-01

    A broad understanding of the numerous ion or plasma assisted surface coating/modification processes is sought. An awareness of the principles of these processes is needed before discussing in detail the ion nitriding technology. On the basis of surface modifications arising from ion or plasma energizing and interactions, it can be broadly classified as deposition of distinct overlay coatings (sputtering-dc, radio frequency, magnetron, reactive; ion plating-diode, triode) and surface property modification without forming a discrete coating (ion implantation, ion beam mixing, laser beam irradiation, ion nitriding, ion carburizing, plasma oxidation. These techniques offer a great flexibility and are capable in tailoring desirable chemical and structural surface properties independent of the bulk properties.

  20. ANFIS Modeling of the Surface Roughness in Grinding Process

    OpenAIRE

    H. Baseri; G. Alinejad

    2011-01-01

    The objective of this study is to design an adaptive neuro-fuzzy inference system (ANFIS) for estimation of surface roughness in grinding process. The Used data have been generated from experimental observations when the wheel has been dressed using a rotary diamond disc dresser. The input parameters of model are dressing speed ratio, dressing depth and dresser cross-feed rate and output parameter is surface roughness. In the experimental procedure the grinding conditions...

  1. Scaling behaviour of randomly alternating surface growth processes

    CERN Document Server

    Raychaudhuri, S

    2002-01-01

    The scaling properties of the roughness of surfaces grown by two different processes randomly alternating in time are addressed. The duration of each application of the two primary processes is assumed to be independently drawn from given distribution functions. We analytically address processes in which the two primary processes are linear and extend the conclusions to nonlinear processes as well. The growth scaling exponent of the average roughness with the number of applications is found to be determined by the long time tail of the distribution functions. For processes in which both mean application times are finite, the scaling behaviour follows that of the corresponding cyclical process in which the uniform application time of each primary process is given by its mean. If the distribution functions decay with a small enough power law for the mean application times to diverge, the growth exponent is found to depend continuously on this power-law exponent. In contrast, the roughness exponent does not depe...

  2. Poorly processed reusable surface disinfection tissue dispensers may be a source of infection.

    Science.gov (United States)

    Kampf, Günter; Degenhardt, Stina; Lackner, Sibylle; Jesse, Katrin; von Baum, Heike; Ostermeyer, Christiane

    2014-01-21

    Reusable surface disinfectant tissue dispensers are used in hospitals in many countries because they allow immediate access to pre-soaked tissues for targeted surface decontamination. On the other hand disinfectant solutions with some active ingredients may get contaminated and cause outbreaks. We determined the frequency of contaminated surface disinfectant solutions in reusable dispensers and the ability of isolates to multiply in different formulations. Reusable tissue dispensers with different surface disinfectants were randomly collected from healthcare facilities. Solutions were investigated for bacterial contamination. The efficacy of two surface disinfectants was determined in suspension tests against two isolated species directly from a contaminated solution or after 5 passages without selection pressure in triplicate. Freshly prepared use solutions were contaminated to determine survival of isolates. 66 dispensers containing disinfectant solutions with surface-active ingredients were collected in 15 healthcare facilities. 28 dispensers from nine healthcare facilities were contaminated with approximately 107 cells per mL of Achromobacter species 3 (9 hospitals), Achromobacter xylosoxidans or Serratia marcescens (1 hospital each). In none of the hospitals dispenser processing had been adequately performed. Isolates regained susceptibility to the disinfectants after five passages without selection pressure but were still able to multiply in different formulations from different manufacturers at room temperature within 7 days. Neglecting adequate processing of surface disinfectant dispensers has contributed to frequent and heavy contamination of use-solutions based on surface active ingredients. Tissue dispenser processing should be taken seriously in clinical practice.

  3. Scaling behaviour of randomly alternating surface growth processes

    International Nuclear Information System (INIS)

    Raychaudhuri, Subhadip; Shapir, Yonathan

    2002-01-01

    The scaling properties of the roughness of surfaces grown by two different processes randomly alternating in time are addressed. The duration of each application of the two primary processes is assumed to be independently drawn from given distribution functions. We analytically address processes in which the two primary processes are linear and extend the conclusions to nonlinear processes as well. The growth scaling exponent of the average roughness with the number of applications is found to be determined by the long time tail of the distribution functions. For processes in which both mean application times are finite, the scaling behaviour follows that of the corresponding cyclical process in which the uniform application time of each primary process is given by its mean. If the distribution functions decay with a small enough power law for the mean application times to diverge, the growth exponent is found to depend continuously on this power-law exponent. In contrast, the roughness exponent does not depend on the timing of the applications. The analytical results are supported by numerical simulations of various pairs of primary processes and with different distribution functions. Self-affine surfaces grown by two randomly alternating processes are common in nature (e.g., due to randomly changing weather conditions) and in man-made devices such as rechargeable batteries

  4. Surface composition of carburized tungsten trioxide and its catalytic activity

    International Nuclear Information System (INIS)

    Nakazawa, M.; Okamoto, H.

    1985-01-01

    The surface composition and electronic structure of carburized tungsten trioxide are investigated using x-ray photoelectron spectroscopy (XPS). The relationship between the surface composition and the catalytic activity for methanol electro-oxidation is clarified. The tungsten carbide concentration in the surface layer increases with the carburization time. The formation of tungsten carbide enhances the catalytic activity. On the other hand, the presence of free carbon or tungsten trioxide in the surface layer reduces the activity remarkably. It is also shown that, the higher the electronic density of states near the Fermi level, the higher the catalytic activity

  5. Stochastic Description of Activated Surface Diffusion with Interacting Adsorbates

    Science.gov (United States)

    Martínez-Casado, Ruth; Vega, José Luis; Sanz, Ángel S.; Miret-Artés, Salvador

    Activated surface diffusion on metal surfaces is receiving much attention both experimentally and theoretically. One of the main theoretical problems in this field is to explain the line-shape broadening observed when the surface coverage is increased. Recently, we have proposed a fully stochastic model, the interacting single adsorbate (ISA) model, aimed at explaining and understanding this type of experiments, which essentially consists of considering the classical Langevin formulation with two types of noise forces: (i) a Gaussian white noise accounting for the substrate friction, and (ii) a shot noise simulating the interacting adsorbates at different coverages. No interaction potential between adsorbates is included because any trace of microscopic interaction seems to be wiped out in a Markovian regime. This model describes in a good approximation, and at a very low computational cost, the line-shape broadening observed experimentally. Furthermore, its mathematical simplicity also allows to derive some analytical expressions which are of much help in the interpretation of the physics underlying surface diffusion processes.

  6. Liquid effluent processing group. Activity details 1963

    International Nuclear Information System (INIS)

    1964-08-01

    This report first gives a quantitative overview of volumes of effluents of high activity, medium activity and low activity which passed through the department for effluent processing. It also makes the distinction between the shape or type of container of these effluents. A table indicates their origin and another indicates their destination. The β and α decontamination rates are determined, and the assessment of stored aqueous and organic effluents on the 31 December 1963 is given. The next part proposes an assessment of laboratory activities: control operations (input controls, control of processed effluent before discarding), controls related to processing (processing types, radiochemical and chemical dosing performed on effluent mixes before processing). Tables indicate the characteristics of medium activity effluents collected in 1963, the results of high activity liquid analysis, and Beryllium dosing results. A summary of ALEA processing, a table of the characteristics of stored oils and solvents are given. The third part reports data related to transport activities, and various works performed in the Saclay plant to improve exploitation conditions and results

  7. Food-safe modification of stainless steel food processing surfaces to reduce bacterial biofilms.

    Science.gov (United States)

    Awad, Tarek Samir; Asker, Dalal; Hatton, Benjamin D

    2018-06-11

    Biofilm formation on stainless steel (SS) surfaces of food processing plants, leading to foodborne illness outbreaks, is enabled by the attachment and confinement within microscale cavities of surface roughness (grooves, scratches). We report Foodsafe Oil-based Slippery Coatings (FOSCs) for food processing surfaces that suppress bacterial adherence and biofilm formation by trapping residual oil lubricant within these surface cavities to block microbial growth. SS surfaces were chemically functionalized with alkylphosphonic acid to preferentially wet a layer of food grade oil. FOSCs reduced the effective surface roughness, the adhesion of organic food residue, and bacteria. FOSCs significantly reduced Pseudomonas aeruginosa biofilm formation on standard roughness SS-316 by 5 log CFU cm-2, and by 3 log CFU cm-2 for mirror-finished SS. FOSCs also enhanced surface cleanability, which we measured by bacterial counts after conventional detergent cleaning. Importantly, both SS grades maintained their anti-biofilm activity after erosion of the oil layer by surface wear with glass beads, which suggests there is a residual volume of oil that remains to block surface cavity defects. These results indicate the potential of such low-cost, scalable approaches to enhance the cleanability of SS food processing surfaces and improve food safety by reducing biofilm growth.

  8. EXPERIMENTAL VALIDATION OF CUMULATIVE SURFACE LOCATION ERROR FOR TURNING PROCESSES

    Directory of Open Access Journals (Sweden)

    Adam K. Kiss

    2016-02-01

    Full Text Available The aim of this study is to create a mechanical model which is suitable to investigate the surface quality in turning processes, based on the Cumulative Surface Location Error (CSLE, which describes the series of the consecutive Surface Location Errors (SLE in roughing operations. In the established model, the investigated CSLE depends on the currently and the previously resulted SLE by means of the variation of the width of cut. The phenomenon of the system can be described as an implicit discrete map. The stationary Surface Location Error and its bifurcations were analysed and flip-type bifurcation was observed for CSLE. Experimental verification of the theoretical results was carried out.

  9. Particle dry deposition to water surfaces: Processes and consequences

    DEFF Research Database (Denmark)

    Pryor, S.C.; Barthelmie, R.J.

    2000-01-01

    flux to coastal waters, atmosphere-surface exchange represents a significant component of the total flux and may be particularly critical during the summertime when both the riverine input and ambient nutrient concentrations are often at a minimum. In this chapter, we present an overview...... of the physical and chemical processes which dictate the quantity (and direction) of atmosphere-surface fluxes of trace chemicals to (and above) water surfaces with particular emphasis on the role of particles. Dry deposition (transfer to the surface in the absence of precipitation) of particles is determined...... efforts to simulate and measure fluxes close to the coastline. These arise in part from the complexity of atmospheric flow in this region where energy and chemical fluxes are highly inhomogeneous in space and time and thermally generated atmospheric circulations are commonplace. (C) 2000 Elsevier Science...

  10. Monitoring tablet surface roughness during the film coating process

    DEFF Research Database (Denmark)

    Seitavuopio, Paulus; Heinämäki, Jyrki; Rantanen, Jukka

    2006-01-01

    The purpose of this study was to evaluate the change of surface roughness and the development of the film during the film coating process using laser profilometer roughness measurements, SEM imaging, and energy dispersive X-ray (EDX) analysis. Surface roughness and texture changes developing during...... the process of film coating tablets were studied by noncontact laser profilometry and scanning electron microscopy (SEM). An EDX analysis was used to monitor the magnesium stearate and titanium dioxide of the tablets. The tablet cores were film coated with aqueous hydroxypropyl methylcellulose, and the film...... coating was performed using an instrumented pilot-scale side-vented drum coater. The SEM images of the film-coated tablets showed that within the first 30 minutes, the surface of the tablet cores was completely covered with a thin film. The magnesium signal that was monitored by SEM-EDX disappeared after...

  11. Surface Dynamic Process Simulation with the Use of Cellular Automata

    International Nuclear Information System (INIS)

    Adamska-Szatko, M.; Bala, J.

    2010-01-01

    Cellular automata are known for many applications, especially for physical and biological simulations. Universal cellular automata can be used for modelling complex natural phenomena. The paper presents simulation of surface dynamic process. Simulation uses 2-dimensional cellular automata algorithm. Modelling and visualisation were created by in-house developed software with standard OpenGL graphic library. (authors)

  12. Process for encapsulating active agents in gels

    NARCIS (Netherlands)

    Yilmaz, G.; Jongboom, R.O.J.; Oosterhaven, J.

    2001-01-01

    The present invention relates to a process for encapsulating an active agent in a biopolymer in the form of a gel, comprising the steps of: a) forming a dispersion or solution of the biopolymer in water; and b) adding the active agent to the dispersion or solution obtained in step a); wherein the

  13. Assessment of surface contamination level in an operating uranium ore processing facility of Jaduguda, India

    International Nuclear Information System (INIS)

    Meena, J.S.; Patnaik, R.L.; Jha, V.N.; Sahoo, S.K.; Ravi, P.M.; Tripathi, R.M.

    2014-01-01

    Radiological concern of the occupational workers and the area is given priority over other safety issue in confirmation with the stipulated guideline of national regulatory agency (AERB/FEFCF/SG-2, 2007). The key concern from the radiological hazard evaluation point of view is air activity, external gamma level and surface contamination. Present investigations was carried out to ascertain the surface contamination level of uranium ore processing facility at Jaduguda, Jharkhand. For a low grade uranium ore processing industry surface contamination is a major concern in product precipitation and recovery section. In view of this, the ore processing plant can broadly be classified into three areas i.e. ion exchange area, precipitation and product recovery section and other areas. The monitoring results incorporate the level of surface contamination of the plant during the last five years. The geometric mean activity of surface contamination level was 31.1, 34.5 and 9.8 Bq dm -2 in ion exchange, product precipitation and recovery and other areas with GSD of 2, 2.5 and 1.9. In most of the cases the surface contamination level was well within the recommended limit of 100 Bq dm -2 for M class uranium compound. Occasional cases of surface contamination levels exceeding the recommended limit were addressed and areas were decontaminated. Based on the study, modification in the design feature of the surface of the finished product section was also suggested so that the decontamination procedure can be more effectively implemented

  14. [Detection of surface EMG signal using active electrode].

    Science.gov (United States)

    He, Qinghua; Peng, Chenglin; Wu, Baoming; Wang, He

    2003-09-01

    Research of surface electromyogram(EMG) signal is important in rehabilitation medicine, sport medicine and clinical diagnosis, accurate detection of signal is the base of quantitative analysis of surface EMG signal. In this article were discussed how to reduce possible noise in the detection of surface EMG. Considerations on the design of electrode unit were presented. Instrumentation amplifier AD620 was employed to design a bipolar active electrode for use in surface EMG detection. The experiments showed that active electrode could be used to improve signal/noise ratio, reduce noise and detect surface EMG signal effectively.

  15. Low-frequency active surface plasmon optics on semiconductors

    NARCIS (Netherlands)

    Gómez Rivas, J.; Kuttge, M.; Kurz, H.; Haring Bolivar, P.; Sánchez-Gil, J.A.

    2006-01-01

    A major challenge in the development of surface plasmon optics or plasmonics is the active control of the propagation of surface plasmon polaritons (SPPs). Here, we demonstrate the feasibility of low-frequency active plasmonics using semiconductors. We show experimentally that the Bragg scattering

  16. Critical reflection activation analysis - a new near-surface probe

    International Nuclear Information System (INIS)

    Gunn, J.M.F.; Trohidou, K.N.

    1988-09-01

    We propose a new surface analytic technique, Critical Reflection Activation Analysis (CRAA). This technique allows accurate depth profiling of impurities ≤ 100A beneath a surface. The depth profile of the impurity is simply related to the induced activity as a function of the angle of reflection. We argue that the technique is practical and estimate its accuracy. (author)

  17. The esa earth explorer land surface processes and interactions mission

    Science.gov (United States)

    Labandibar, Jean-Yves; Jubineau, Franck; Silvestrin, Pierluigi; Del Bello, Umberto

    2017-11-01

    The European Space Agency (ESA) is defining candidate missions for Earth Observation. In the class of the Earth Explorer missions, dedicated to research and pre-operational demonstration, the Land Surface Processes and Interactions Mission (LSPIM) will acquire the accurate quantitative measurements needed to improve our understanding of the nature and evolution of biosphere-atmosphere interactions and to contribute significantly to a solution of the scaling problems for energy, water and carbon fluxes at the Earth's surface. The mission is intended to provide detailed observations of the surface of the Earth and to collect data related to ecosystem processes and radiation balance. It is also intended to address a range of issues important for environmental monitoring, renewable resources assessment and climate models. The mission involves a dedicated maneuvering satellite which provides multi-directional observations for systematic measurement of Land Surface BRDF (BiDirectional Reflectance Distribution Function) of selected sites on Earth. The satellite carries an optical payload : PRISM (Processes Research by an Imaging Space Mission), a multispectral imager providing reasonably high spatial resolution images (50 m over 50 km swath) in the whole optical spectral domain (from 450 nm to 2.35 μm with a resolution close to 10 nm, and two thermal bands from 8.1 to 9.1 μm). This paper presents the results of the Phase A study awarded by ESA, led by ALCATEL Space Industries and concerning the design of LSPIM.

  18. Integrated system of production information processing for surface mines

    Energy Technology Data Exchange (ETDEWEB)

    Li, K.; Wang, S.; Zeng, Z.; Wei, J.; Ren, Z. [China University of Mining and Technology, Xuzhou (China). Dept of Mining Engineering

    2000-09-01

    Based on the concept of geological statistic, mathematical program, condition simulation, system engineering, and the features and duties of each main department in surface mine production, an integrated system for surface mine production information was studied systematically and developed by using the technology of data warehousing, CAD, object-oriented and system integration, which leads to the systematizing and automating of the information management, data processing, optimization computing and plotting. In this paper, its overall object, system design, structure and functions and some key techniques were described. 2 refs., 3 figs.

  19. Auto-recognition of surfaces and auto-generation of material removal volume for finishing process

    Science.gov (United States)

    Kataraki, Pramod S.; Salman Abu Mansor, Mohd

    2018-03-01

    Auto-recognition of a surface and auto-generation of material removal volumes for the so recognised surfaces has become a need to achieve successful downstream manufacturing activities like automated process planning and scheduling. Few researchers have contributed to generation of material removal volume for a product but resulted in material removal volume discontinuity between two adjacent material removal volumes generated from two adjacent faces that form convex geometry. The need for limitation free material removal volume generation was attempted and an algorithm that automatically recognises computer aided design (CAD) model’s surface and also auto-generate material removal volume for finishing process of the recognised surfaces was developed. The surfaces of CAD model are successfully recognised by the developed algorithm and required material removal volume is obtained. The material removal volume discontinuity limitation that occurred in fewer studies is eliminated.

  20. Dominant rate process of silicon surface etching by hydrogen chloride gas

    International Nuclear Information System (INIS)

    Habuka, Hitoshi; Suzuki, Takahiro; Yamamoto, Sunao; Nakamura, Akio; Takeuchi, Takashi; Aihara, Masahiko

    2005-01-01

    Silicon surface etching and its dominant rate process are studied using hydrogen chloride gas in a wide concentration range of 1-100% in ambient hydrogen at atmospheric pressure in a temperature range of 1023-1423 K, linked with the numerical calculation accounting for the transport phenomena and the surface chemical reaction in the entire reactor. The etch rate, the gaseous products and the surface morphology are experimentally evaluated. The dominant rate equation accounting for the first-order successive reactions at silicon surface by hydrogen chloride gas is shown to be valid. The activation energy of the dominant surface process is evaluated to be 1.5 x 10 5 J mol - 1 . The silicon deposition by the gaseous by-product, trichlorosilane, is shown to have a negligible influence on the silicon etch rate

  1. Physical activity (PA) and the disablement process

    DEFF Research Database (Denmark)

    Schultz-Larsen, Kirsten; Rahmanfard, Naghmeh; Holst, Claus

    2012-01-01

    . Among older women, the association between RPA and incidence of disability was attenuated in analyses that controlled for baseline mobility function. Thus, the association between physical activity and mortality reflected processes different from those underlying a simple relation between physical...... activity, disability and mortality. Physical activity was an ubiquitous predictor of longevity, but only for women....... community-living persons, aged 75-83 years, we evaluated the 1021 who reported no disability in basic activities of daily living. Participants were followed for a median of 8.34 years in public registers to determine onset of disability and mortality. RPA predicted mortality in older women (HR=1.77, 95%CI=1...

  2. Experience with antimony activity removal process in Indian PHWRs

    International Nuclear Information System (INIS)

    Velmurugan, S.; Mittal, Vinit K.; Kumbhar, A.G.; Narasimhan, S.V.; Bhat, H.R.; Krishna Rao, K.S.; Upadhyay, S.K.; Jain, A.K.

    2008-01-01

    The problem of antimony (Sb) activity during decontamination was first encountered in NAPS-1 and Sb activity deposition took place during the decontamination resulting in poor decontamination factors (DF). Sb problem has been observed in PWRs and PHWRs elsewhere also. These utilities use an oxidative process involving the addition of H 2 O 2 to remove these Sb activities from the core and remove it on ion exchange resins. Experience in CANDU PHWRs indicated disappearance of H 2 O 2 in quantities higher than that observed in PWRs. This is attributed to the higher pick-up of H 2 O 2 by the magnetite/ferrites over large carbon steel surface present in the primary coolant system of PHWRs. Systematic work was carried out to understand the deposition of Sb on PHT system surfaces and a new method was evolved to remove the Sb activities from the system. This alternative reductive chemical process involve the addition of Nitrilo Tri Acetic Acid, Citric Acid and Rodine-92B and circulating the chemicals for a short period and then the Sb and other activities released from the core are removed by the mixed bed. Subsequent to the Sb removal process, the normal chemical decontamination of the system is carried out to remove 60 Co and other activities. This non-oxidizing Sb removal process was applied to NAPS-2 primary system prior to EMCCR. During this Sb removal process of NAPS-2, around 450 μCi/L activity of 124 Sb was released from the system surfaces to the formulation. Activity measurement in the samples collected and the on-line radiation field data indicated that deposition of Sb activities on system surfaces has been prevented by Rodine-92B and subsequently these activities have been removed by mixed bed IX columns. Antimony removal process worked successfully, but in the second normal decontamination process around 150 μCi/L activities came in the formulation which was not anticipated. As a result DF observed immediately after the decontamination campaign was not good

  3. Advantages of surface treatment processes by ionic sputtering

    International Nuclear Information System (INIS)

    Gantois, M.

    1976-01-01

    The use of high intensity glow-discharge permits to realize a superficial thermochemical treatment. Ions formed by discharge are accelerated against the surfaces to be treated; by effect of ion bombardment, surfaces get heated and a chemical reaction is developed depending on the composition of the ionized gas. The technique presents advantages, as the potential of the active gas might be freely chosen, and as many gases might be used, the decomposition of gases by pyrolysis and a homogeneous treatment (concerning nature of phases and thickness) all over the surface being not necessary. It is possible to develop layers of various nature, looking for those which offer the best properties to solve a technological problem (wear, friction, fatigue toughness, etc.). Some examples of nitruration, carbonitruration are considered [fr

  4. Mechanical and tribological properties of ion beam-processed surfaces

    International Nuclear Information System (INIS)

    Kodali, P.

    1998-01-01

    The intent of this work was to broaden the applications of well-established surface modification techniques and to elucidate the various wear mechanisms that occur in sliding contact of ion-beam processed surfaces. The investigation included characterization and evaluation of coatings and modified surfaces synthesized by three surface engineering methods; namely, beam-line ion implantation, plasma-source ion implantation, and DC magnetron sputtering. Correlation among measured properties such as surface hardness, fracture toughness, and wear behavior was also examined. This dissertation focused on the following areas of research: (1) investigating the mechanical and tribological properties of mixed implantation of carbon and nitrogen into single crystal silicon by beam-line implantation; (2) characterizing the mechanical and tribological properties of diamond-like carbon (DLC) coatings processed by plasma source ion implantation; and (3) developing and evaluating metastable boron-carbon-nitrogen (BCN) compound coatings for mechanical and tribological properties. The surface hardness of a mixed carbon-nitrogen implant sample improved significantly compared to the unimplanted sample. However, the enhancement in the wear factor of this sample was found to be less significant than carbon-implanted samples. The presence of nitrogen might be responsible for the degraded wear behavior since nitrogen-implantation alone resulted in no improvement in the wear factor. DLC coatings have low friction, low wear factor, and high hardness. The fracture toughness of DLC coatings has been estimated for the first time. The wear mechanism in DLC coatings investigated with a ruby slider under a contact stress of 1 GPa was determined to be plastic deformation. The preliminary data on metastable BCN compound coatings indicated high friction, low wear factor, and high hardness

  5. Activity-Dependent Regulation of Surface Glucose Transporter-3

    OpenAIRE

    Ferreira, Jainne M.; Burnett, Arthur L.; Rameau, Gerald A.

    2011-01-01

    Glucose transporter 3 (GLUT3) is the main facilitative glucose transporter in neurons. Glucose provides neurons with a critical energy source for neuronal activity. However, the mechanism by which neuronal activity controls glucose influx via GLUT3 is unknown. We investigated the influence of synaptic stimulation on GLUT3 surface expression and glucose import in primary cultured cortical and hippocampal neurons. Synaptic activity increased surface expression of GLUT3 leading to an elevation o...

  6. Surface processes during purification of InP quantum dots

    Directory of Open Access Journals (Sweden)

    Natalia Mordvinova

    2014-08-01

    Full Text Available Recently, a new simple and fast method for the synthesis of InP quantum dots by using phosphine as phosphorous precursor and myristic acid as surface stabilizer was reported. Purification after synthesis is necessary to obtain samples with good optical properties. Two methods of purification were compared and the surface processes which occur during purification were studied. Traditional precipitation with acetone is accompanied by a small increase in photoluminescence. It occurs that during the purification the hydrolysis of the indium precursor takes place, which leads to a better surface passivation. The electrophoretic purification technique does not increase luminescence efficiency but yields very pure quantum dots in only a few minutes. Additionally, the formation of In(OH3 during the low temperature synthesis was explained. Purification of quantum dots is a very significant part of postsynthetical treatment that determines the properties of the material. But this subject is not sufficiently discussed in the literature. The paper is devoted to the processes that occur at the surface of quantum dots during purification. A new method of purification, electrophoresis, is investigated and described in particular.

  7. Surface enhanced Raman optical activity (SEROA)

    DEFF Research Database (Denmark)

    Abdali, Salim; Blanch, E.W.

    2008-01-01

    Raman optical activity (ROA) directly monitors the stereochemistry of chiral molecules and is now an incisive probe of biomolecular structure. ROA spectra contain a wealth of information on tertiary folding, secondary structure and even the orientation of individual residues in proteins and nucleic...

  8. Application of Anodization Process for Cast Aluminium Surface Properties Enhancement

    Directory of Open Access Journals (Sweden)

    Włodarczyk-Fligier A.

    2016-09-01

    Full Text Available An huge interest is observed in last years in metal matrix composite, mostly light metal based, which have found their applications in many industry branches, among others in the aircraft industry, automotive-, and armaments ones, as well as in electrical engineering and electronics, where one of the most important issue is related to the corrosion resistance, especially on the surface layer of the used aluminium alloys. This elaboration presents the influence of ceramic phase on the corrosion resistance, quality of the surface layer its thickness and structure of an anodic layer formed on aluminium alloys. As test materials it was applied the aluminium alloys Al-Si-Cu and Al-Cu-Mg, for which heat treatment processes and corrosion tests were carried out. It was presented herein grindability test results and metallographic examination, as well. Hardness of the treated alloys with those ones subjected to corrosion process were compared.

  9. Antioxidant Activity from Various Tomato Processing

    Directory of Open Access Journals (Sweden)

    Retno Sri Iswari

    2016-04-01

    Full Text Available Tomato is one of the high antioxidant potential vegetables. Nowadays, there are many techniques of tomato processings instead of fresh consumption, i.e. boiled, steamed, juiced and sauteed. Every treatment of cooking will influence the chemical compound inside the fruits and the body's nutrition intake. It is important to conduct the research on antioxidant compound especially lycopene, β-carotene, vitamin C, α-tocopherol, and its activity after processing. This research has been done using the experimental method. Tomatoes were cooked into six difference ways, and then it was extracted using the same procedure continued with antioxidant measurement. The research results showed that steaming had promoted the higher antioxidant numbers (lycopene. α-tocopherol, β-carotene and vitamin C and higher TCA and antioxidant activities in the tomatoes than other processings. It was indicated that steaming was the best way to enhance amount, capacity and activities of antioxidants of the tomatoes.

  10. Laser surface processing with controlled nitrogen-argon concentration levels for regulated surface life time

    Science.gov (United States)

    Obeidi, M. Ahmed; McCarthy, E.; Brabazon, D.

    2018-03-01

    Laser surface modification can be used to enhance the mechanical properties of a material, such as hardness, toughness, fatigue strength, and corrosion resistance. Surface nitriding is a widely used thermochemical method of surface modification, in which nitrogen is introduced into a metal or other material at an elevated temperature within a furnace. It is used on parts where there is a need for increased wear resistance, corrosion resistance, fatigue life, and hardness. Laser nitriding is a novel method of nitriding where the surface is heated locally by a laser, either in an atmosphere of nitrogen or with a jet of nitrogen delivered to the laser heated site. It combines the benefits of laser modification with those of nitriding. Recent work on high toughness tool steel samples has shown promising results due to the increased nitrogen gas impingement onto the laser heated region. Increased surface activity and nitrogen adsorption was achieved which resulted in a deeper and harder surface compared to conventional hardening methods. In this work, the effects of the laser power, pulse repetition frequency, and overlap percentage on laser surface treatment of 316 L SST steel samples with an argon-nitrogen jet will be presented. Resulting microstructure, phase type, microhardness, and wear resistance are presented.

  11. Estimation of surface absorptivity in laser surface heating process with experimental data

    International Nuclear Information System (INIS)

    Chen, H-T; Wu, X-Y

    2006-01-01

    This study applies a hybrid technique of the Laplace transform and finite-difference methods in conjunction with the least-squares method and experimental temperature data inside the test material to predict the unknown surface temperature, heat flux and absorptivity for various surface conditions in the laser surface heating process. In this study, the functional form of the surface temperature is unknown a priori and is assumed to be a function of time before performing the inverse calculation. In addition, the whole time domain is divided into several analysis sub-time intervals and then these unknown estimates on each analysis interval can be predicted. In order to show the accuracy of the present inverse method, comparisons are made among the present estimates, direct results and previous results, showing that the present estimates agree with the direct results for the simulated problem. However, the present estimates of the surface absorptivity deviate slightly from previous estimated results under the assumption of constant thermal properties. The effect of the surface conditions on the surface absorptivity and temperature is not negligible

  12. Probing Interfacial Processes on Graphene Surface by Mass Detection

    Science.gov (United States)

    Kakenov, Nurbek; Kocabas, Coskun

    2013-03-01

    In this work we studied the mass density of graphene, probed interfacial processes on graphene surface and examined the formation of graphene oxide by mass detection. The graphene layers were synthesized by chemical vapor deposition method on copper foils and transfer-printed on a quartz crystal microbalance (QCM). The mass density of single layer graphene was measured by investigating the mechanical resonance of the QCM. Moreover, we extended the developed technique to probe the binding dynamics of proteins on the surface of graphene, were able to obtain nonspecific binding constant of BSA protein of graphene surface in aqueous solution. The time trace of resonance signal showed that the BSA molecules rapidly saturated by filling the available binding sites on graphene surface. Furthermore, we monitored oxidation of graphene surface under oxygen plasma by tracing the changes of interfacial mass of the graphene controlled by the shifts in Raman spectra. Three regimes were observed the formation of graphene oxide which increases the interfacial mass, the release of carbon dioxide and the removal of small graphene/graphene oxide flakes. Scientific and Technological Research Council of Turkey (TUBITAK) grant no. 110T304, 109T209, Marie Curie International Reintegration Grant (IRG) grant no 256458, Turkish Academy of Science (TUBA-Gebip).

  13. Acid-base characteristics of powdered-activated-carbon surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Reed, B.E. (West Virginia Univ., Morgantown (United States)); Jensen, J.N.; Matsumoto, M.R. (State Univ. of New York, Buffalo (United States))

    Adsorption of heavy metals onto activated carbon has been described using the surface-complex-formation (SCF) model, a chemical equilibrium model. The SCF model requires a knowledge of the amphoteric nature of activated carbon prior to metal adsorption modeling. In the past, a single-diprotic-acid-site model had been employed to describe the amphoteric nature of activated-carbon surfaces. During this study, the amphoteric nature of two powdered activated carbons were investigated, and a three-monoprotic site surface model was found to be a plausible alternative. The single-diprotic-acid-site and two-monoprotic-site models did not describe the acid-base behavior of the two carbons studied adequately. The two-diprotic site was acceptable for only one of the study carbons. The acid-base behavior of activated carbon surfaces seem to be best modeled as a series of weak monoprotic acids.

  14. Detection of cracks on concrete surfaces by hyperspectral image processing

    Science.gov (United States)

    Santos, Bruno O.; Valença, Jonatas; Júlio, Eduardo

    2017-06-01

    All large infrastructures worldwide must have a suitable monitoring and maintenance plan, aiming to evaluate their behaviour and predict timely interventions. In the particular case of concrete infrastructures, the detection and characterization of crack patterns is a major indicator of their structural response. In this scope, methods based on image processing have been applied and presented. Usually, methods focus on image binarization followed by applications of mathematical morphology to identify cracks on concrete surface. In most cases, publications are focused on restricted areas of concrete surfaces and in a single crack. On-site, the methods and algorithms have to deal with several factors that interfere with the results, namely dirt and biological colonization. Thus, the automation of a procedure for on-site characterization of crack patterns is of great interest. This advance may result in an effective tool to support maintenance strategies and interventions planning. This paper presents a research based on the analysis and processing of hyper-spectral images for detection and classification of cracks on concrete structures. The objective of the study is to evaluate the applicability of several wavelengths of the electromagnetic spectrum for classification of cracks in concrete surfaces. An image survey considering highly discretized wavelengths between 425 nm and 950 nm was performed on concrete specimens, with bandwidths of 25 nm. The concrete specimens were produced with a crack pattern induced by applying a load with displacement control. The tests were conducted to simulate usual on-site drawbacks. In this context, the surface of the specimen was subjected to biological colonization (leaves and moss). To evaluate the results and enhance crack patterns a clustering method, namely k-means algorithm, is being applied. The research conducted allows to define the suitability of using clustering k-means algorithm combined with hyper-spectral images highly

  15. Novel CNC Grinding Process Control for Nanometric Surface Roughness for Aspheric Space Optical Surfaces

    Directory of Open Access Journals (Sweden)

    Jeong-Yeol Han

    2004-06-01

    Full Text Available Optics fabrication process for precision space optical parts includes bound abrasive grinding, loose abrasive lapping and polishing. The traditional bound abrasive grinding with bronze bond cupped diamond wheel leaves the machine marks of about 20 μm rms in height and the subsurface damage of about 1 μm rms in height to be removed by subsequent loose abrasive lapping. We explored an efficient quantitative control of precision CNC grinding. The machining parameters such as grain size, work-piece rotation speed and feed rate were altered while grinding the work-piece surfaces of 20-100 mm in diameter. The input grinding variables and the resulting surface quality data were used to build grinding prediction models using empirical and multi-variable regression analysis. The effectiveness of such grinding prediction models was then examined by running a series of precision CNC grinding operation with a set of controlled input variables and predicted output surface quality indicators. The experiment achieved the predictability down to ±20 nm in height and the surface roughness down to 36 nm in height. This study contributed to improvement of the process efficiency reaching directly the polishing and figuring process without the need for the loose abrasive lapping stage.

  16. Processing of Color Words Activates Color Representations

    Science.gov (United States)

    Richter, Tobias; Zwaan, Rolf A.

    2009-01-01

    Two experiments were conducted to investigate whether color representations are routinely activated when color words are processed. Congruency effects of colors and color words were observed in both directions. Lexical decisions on color words were faster when preceding colors matched the color named by the word. Color-discrimination responses…

  17. Dynamics of gas-surface interactions atomic-level understanding of scattering processes at surfaces

    CERN Document Server

    Díez Muniño, Ricardo

    2013-01-01

    This book gives a representative survey of the state of the art of research on gas-surface interactions. It provides an overview of the current understanding of gas surface dynamics and, in particular, of the reactive and non-reactive processes of atoms and small molecules at surfaces. Leading scientists in the field, both from the theoretical and the experimental sides, write in this book about their most recent advances. Surface science grew as an interdisciplinary research area over the last decades, mostly because of new experimental technologies (ultra-high vacuum, for instance), as well as because of a novel paradigm, the ‘surface science’ approach. The book describes the second transformation which is now taking place pushed by the availability of powerful quantum-mechanical theoretical methods implemented numerically. In the book, experiment and theory progress hand in hand with an unprecedented degree of accuracy and control. The book presents how modern surface science targets the atomic-level u...

  18. Using infrared thermography for understanding and quantifying soil surface processes

    Science.gov (United States)

    de Lima, João L. M. P.

    2017-04-01

    At present, our understanding of the soil hydrologic response is restricted by measurement limitations. In the literature, there have been repeatedly calls for interdisciplinary approaches to expand our knowledge in this field and eventually overcome the limitations that are inherent to conventional measuring techniques used, for example, for tracing water at the basin, hillslope and even field or plot scales. Infrared thermography is a versatile, accurate and fast technique of monitoring surface temperature and has been used in a variety of fields, such as military surveillance, medical diagnosis, industrial processes optimisation, building inspections and agriculture. However, many applications are still to be fully explored. In surface hydrology, it has been successfully employed as a high spatial and temporal resolution non-invasive and non-destructive imaging tool to e.g. access groundwater discharges into waterbodies or quantify thermal heterogeneities of streams. It is believed that thermal infrared imagery can grasp the spatial and temporal variability of many processes at the soil surface. Thermography interprets the heat signals and can provide an attractive view for identifying both areas where water is flowing or has infiltrated more, or accumulated temporarily in depressions or macropores. Therefore, we hope to demonstrate the potential for thermal infrared imagery to indirectly make a quantitative estimation of several hydrologic processes. Applications include: e.g. mapping infiltration, microrelief and macropores; estimating flow velocities; defining sampling strategies; identifying water sources, accumulation of waters or even connectivity. Protocols for the assessment of several hydrologic processes with the help of IR thermography will be briefly explained, presenting some examples from laboratory soil flumes and field.

  19. Influence of surface coverage on the chemical desorption process

    Energy Technology Data Exchange (ETDEWEB)

    Minissale, M.; Dulieu, F., E-mail: francois.dulieu@obspm.fr [LERMA, Université de Cergy Pontoise et Observatoire de Paris, UMR 8112 du CNRS. 5, mail Gay Lussac, 95031 Cergy Pontoise (France)

    2014-07-07

    In cold astrophysical environments, some molecules are observed in the gas phase whereas they should have been depleted, frozen on dust grains. In order to solve this problem, astrochemists have proposed that a fraction of molecules synthesized on the surface of dust grains could desorb just after their formation. Recently the chemical desorption process has been demonstrated experimentally, but the key parameters at play have not yet been fully understood. In this article, we propose a new procedure to analyze the ratio of di-oxygen and ozone synthesized after O atoms adsorption on oxidized graphite. We demonstrate that the chemical desorption efficiency of the two reaction paths (O+O and O+O{sub 2}) is different by one order of magnitude. We show the importance of the surface coverage: for the O+O reaction, the chemical desorption efficiency is close to 80% at zero coverage and tends to zero at one monolayer coverage. The coverage dependence of O+O chemical desorption is proved by varying the amount of pre-adsorbed N{sub 2} on the substrate from 0 to 1.5 ML. Finally, we discuss the relevance of the different physical parameters that could play a role in the chemical desorption process: binding energy, enthalpy of formation, and energy transfer from the new molecule to the surface or to other adsorbates.

  20. Decontamination Efficiency of Fish Bacterial Flora from Processing Surfaces

    Directory of Open Access Journals (Sweden)

    Birna Guðbjörnsdóttir

    2009-01-01

    Full Text Available There are numerous parameters that can influence bacterial decontamination during washing of machinery and equipment in a food processing establishment. Incomplete decontamination of bacteria will increase the risk of biofilm formation and consequently increase the risk of pathogen contamination or prevalence of other undesirable microorganisms such as spoilage bacteria in the processing line. The efficiency of a typical washing protocol has been determined by testing three critical parameters and their effects on bacterial decontamination. Two surface materials (plastic and stainless steel, water temperatures (7 and 25 °C and detergent concentrations (2 and 4 % were used for this purpose in combination with two types of detergents. Biofilm was prepared on the surfaces with undefined bacterial flora obtained from minced cod fillets. The bacterial flora of the biofilm was characterised by cultivation and molecular analysis of 16S rRNA genes. All different combinations of washing protocols tested were able to remove more than 99.9 % of the bacteria in the biofilm and reduce the cell number from 7 to 0 or 2 log units of bacteria/cm2. The results show that it is possible to use less diluted detergents than recommended with comparable success, and it is easier to clean surface material made of stainless steel compared to polyethylene plastic.

  1. Laser processing of metallic biomaterials: An approach for surface patterning and wettability control

    Science.gov (United States)

    Razi, Sepehr; Mollabashi, Mahmoud; Madanipour, Khosro

    2015-12-01

    Q -switched Nd:YAG laser is used to manipulate the surface morphology and wettability characteristic of 316L stainless steel (SS) and titanium biomaterials. Water and glycerol are selected as wettability testing liquids and the sessile drop method is used for the contact angle measurements. Results indicate that on both of the metals, wettability toward water improves significantly after the laser treatment. Different analyses including the study of the surface morphology, free energy and oxidation are assessed in correlation with wettability. Beside the important role of the laser-induced surface patterns, the increase in the surface roughness, oxygen content and the polar component of the surface energy, are detected as the most important physical and chemical phenomena controlling the improvement in the wettability. However, all the processed hydrophilic surfaces that are exposed to air become hydrophobic over time. The time dependency of the surface wettability is related to the chemical activities on the treated surfaces and the reduction of oxygen/carbon (O/C) ratio on them. The behavior is further studied with investigating the effect of the keeping environment and changes of the components of the surface tension. Results show that the pulsed laser treatment is a versatile approach to create either hydrophobic or super hydrophilic surfaces for industrial and medical applications.

  2. Urbanization Process and Variation of Energy Budget of Land Surfaces

    Directory of Open Access Journals (Sweden)

    Ciro Gardi

    2007-06-01

    Full Text Available Urban areas are increasing at a rate much higher than human population growth in many part of the world; actually more than 73 towns in the world are larger than 1000 km2. The European Environmental Agency indicates an urban area average growth rate, over the last 20 years, of 20%. The urbanization process, and the consequent soil sealing, determines not only the losses of the ecological functions of the soil, but also a variation of the energy budget of land surfaces, that affect the microclimatic conditions (heat islands. The alteration of the energy budget are determined by the variations of albedo and roughness of surfaces, but especially by the net losses of evapotranspirating areas. In the present research we have assessed the variation of Parma territory energy budget, induced by the change in land use over the last 122 years. The urban area increase between 1881 and 2003 was 535%.

  3. Quantification of deexcitation processes for analyzing liquid surfaces

    International Nuclear Information System (INIS)

    Morgner, H.

    2014-01-01

    In the last two decades the mathematical tools for quantitative data evaluation have been developed for several surface spectroscopic techniques like Angular Resolved X-ray Photoelectron Spectroscopy (ARXPS), Neutral Impact Collision Ion Scattering Spectroscopy (NICISS) and Metastable Induced Electron Spectroscopy (MIES). Provided that the experimental data are of good quality, quantitative data processing can add a lot to the information that can be gained from surface spectroscopy. We give a selection of references that contain information on these methods. The emphasis of this contribution aims at providing motivation to apply quantitative data evaluation by presenting a few examples. We try to demonstrate, that careful data evaluation may lead to interesting insight into basic concepts as well as to results that are useful for practical applications

  4. Quantification of deexcitation processes for analyzing liquid surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Morgner, H., E-mail: hmorgner@rz.uni-leipzig.de

    2014-12-01

    In the last two decades the mathematical tools for quantitative data evaluation have been developed for several surface spectroscopic techniques like Angular Resolved X-ray Photoelectron Spectroscopy (ARXPS), Neutral Impact Collision Ion Scattering Spectroscopy (NICISS) and Metastable Induced Electron Spectroscopy (MIES). Provided that the experimental data are of good quality, quantitative data processing can add a lot to the information that can be gained from surface spectroscopy. We give a selection of references that contain information on these methods. The emphasis of this contribution aims at providing motivation to apply quantitative data evaluation by presenting a few examples. We try to demonstrate, that careful data evaluation may lead to interesting insight into basic concepts as well as to results that are useful for practical applications.

  5. Surface hardening of two cast irons by friction stir processing

    International Nuclear Information System (INIS)

    Fujii, Hidetoshi; Kikuchi, Toshifumi; Nogi, Kiyoshi; Yamaguchi, Yasufumi; Kiguchi, Shoji

    2009-01-01

    The Friction Stir Processing (FSP) was applied to the surface hardening of cast irons. Flake graphite cast iron (FC300) and nodular graphite cast iron (FCD700) were used to investigate the validity of this method. The matrices of the FC300 and FC700 cast irons are pearlite. The rotary tool is a 25mm diameter cylindrical tool, and the travelling speed was varied between 50 and 150mm/min in order to control the heat input at the constant rotation speed of 900rpm. As a result, it has been clarified that a Vickers hardness of about 700HV is obtained for both cast irons. It is considered that a very fine martensite structure is formed because the FSP generates the heat very locally, and a very high cooling rate is constantly obtained. When a tool without an umbo (probe) is used, the domain in which graphite is crushed and striated is minimized. This leads to obtaining a much harder sample. The hardness change depends on the size of the martensite, which can be controlled by the process conditions, such as the tool traveling speed and the load. Based on these results, it was clarified that the FSP has many advantages for cast irons, such as a higher hardness and lower distortion. As a result, no post surface heat treatment and no post machining are required to obtain the required hardness, while these processes are generally required when using the traditional methods.

  6. The microfluidic probe: operation and use for localized surface processing.

    Science.gov (United States)

    Perrault, Cecile M; Qasaimeh, Mohammad A; Juncker, David

    2009-06-04

    Microfluidic devices allow assays to be performed using minute amounts of sample and have recently been used to control the microenvironment of cells. Microfluidics is commonly associated with closed microchannels which limit their use to samples that can be introduced, and cultured in the case of cells, within a confined volume. On the other hand, micropipetting system have been used to locally perfuse cells and surfaces, notably using push-pull setups where one pipette acts as source and the other one as sink, but the confinement of the flow is difficult in three dimensions. Furthermore, pipettes are fragile and difficult to position and hence are used in static configuration only. The microfluidic probe (MFP) circumvents the constraints imposed by the construction of closed microfluidic channels and instead of enclosing the sample into the microfluidic system, the microfluidic flow can be directly delivered onto the sample, and scanned across the sample, using the MFP. . The injection and aspiration openings are located within a few tens of micrometers of one another so that a microjet injected into the gap is confined by the hydrodynamic forces of the surrounding liquid and entirely aspirated back into the other opening. The microjet can be flushed across the substrate surface and provides a precise tool for localized deposition/delivery of reagents which can be used over large areas by scanning the probe across the surface. In this video we present the microfluidic probe (MFP). We explain in detail how to assemble the MFP, mount it atop an inverted microscope, and align it relative to the substrate surface, and finally show how to use it to process a substrate surface immersed in a buffer.

  7. Electroweak processes in external active media

    CERN Document Server

    Kuznetsov, Alexander

    2013-01-01

    Expanding on the concept of the authors’ previous book “Electroweak Processes in External Electromagnetic Fields,” this new book systematically describes the investigation methods for the effects of external active media, both strong electromagnetic fields and hot dense plasma, in quantum processes. Solving the solar neutrino puzzle in a unique experiment conducted with the help of the heavy-water detector at the Sudbery Neutrino Observatory, along with another neutrino experiments, brings to the fore electroweak physics in an active external medium. It is effectively demonstrated that processes of neutrino interactions with active media of astrophysical objects may lead, under some physical conditions, to such interesting effects as neutrino-driven shockwave revival in a supernova explosion, a “cherry stone shooting” mechanism for pulsar natal kick, and a neutrino pulsar. It is also shown how poor estimates of particle dispersion in external active media sometimes lead to confusion. The book...

  8. Interdependencies of Arctic land surface processes: A uniquely sensitive environment

    Science.gov (United States)

    Bowling, L. C.

    2007-12-01

    The circumpolar arctic drainage basin is composed of several distinct ecoregions including steppe grassland and cropland, boreal forest and tundra. Land surface hydrology throughout this diverse region shares several unique features such as dramatic seasonal runoff differences controlled by snowmelt and ice break-up; the storage of significant portions of annual precipitation as snow and in lakes and wetlands; and the effects of ephemeral and permanently frozen soils. These arctic land processes are delicately balanced with the climate and are therefore important indicators of change. The litany of recently-detected changes in the Arctic includes changes in snow precipitation, trends and seasonal shifts in river discharge, increases and decreases in the extent of surface water, and warming soil temperatures. Although not unique to the arctic, increasing anthropogenic pressures represent an additional element of change in the form of resource extraction, fire threat and reservoir construction. The interdependence of the physical, biological and social systems mean that changes in primary indicators have large implications for land cover, animal populations and the regional carbon balance, all of which have the potential to feed back and induce further change. In fact, the complex relationships between the hydrological processes that make the Artic unique also render observed historical change difficult to interpret and predict, leading to conflicting explanations. For example, a decrease in snow accumulation may provide less insulation to the underlying soil resulting in greater frost development and increased spring runoff. Similarly, melting permafrost and ground ice may lead to ground subsidence and increased surface saturation and methane production, while more complete thaw may enhance drainage and result in drier soil conditions. The threshold nature of phase change around the freezing point makes the system especially sensitive to change. In addition, spatial

  9. Passivation of phosphorus diffused silicon surfaces with Al2O3: Influence of surface doping concentration and thermal activation treatments

    International Nuclear Information System (INIS)

    Richter, Armin; Benick, Jan; Kimmerle, Achim; Hermle, Martin; Glunz, Stefan W.

    2014-01-01

    Thin layers of Al 2 O 3 are well known for the excellent passivation of p-type c-Si surfaces including highly doped p + emitters, due to a high density of fixed negative charges. Recent results indicate that Al 2 O 3 can also provide a good passivation of certain phosphorus-diffused n + c-Si surfaces. In this work, we studied the recombination at Al 2 O 3 passivated n + surfaces theoretically with device simulations and experimentally for Al 2 O 3 deposited with atomic layer deposition. The simulation results indicate that there is a certain surface doping concentration, where the recombination is maximal due to depletion or weak inversion of the charge carriers at the c-Si/Al 2 O 3 interface. This pronounced maximum was also observed experimentally for n + surfaces passivated either with Al 2 O 3 single layers or stacks of Al 2 O 3 capped by SiN x , when activated with a low temperature anneal (425 °C). In contrast, for Al 2 O 3 /SiN x stacks activated with a short high-temperature firing process (800 °C) a significant lower surface recombination was observed for most n + diffusion profiles without such a pronounced maximum. Based on experimentally determined interface properties and simulation results, we attribute this superior passivation quality after firing to a better chemical surface passivation, quantified by a lower interface defect density, in combination with a lower density of negative fixed charges. These experimental results reveal that Al 2 O 3 /SiN x stacks can provide not only excellent passivation on p + surfaces but also on n + surfaces for a wide range of surface doping concentrations when activated with short high-temperature treatments

  10. Speech perception as an active cognitive process

    Directory of Open Access Journals (Sweden)

    Shannon eHeald

    2014-03-01

    Full Text Available One view of speech perception is that acoustic signals are transformed into representations for pattern matching to determine linguistic structure. This process can be taken as a statistical pattern-matching problem, assuming realtively stable linguistic categories are characterized by neural representations related to auditory properties of speech that can be compared to speech input. This kind of pattern matching can be termed a passive process which implies rigidity of processingd with few demands on cognitive processing. An alternative view is that speech recognition, even in early stages, is an active process in which speech analysis is attentionally guided. Note that this does not mean consciously guided but that information-contingent changes in early auditory encoding can occur as a function of context and experience. Active processing assumes that attention, plasticity, and listening goals are important in considering how listeners cope with adverse circumstances that impair hearing by masking noise in the environment or hearing loss. Although theories of speech perception have begun to incorporate some active processing, they seldom treat early speech encoding as plastic and attentionally guided. Recent research has suggested that speech perception is the product of both feedforward and feedback interactions between a number of brain regions that include descending projections perhaps as far downstream as the cochlea. It is important to understand how the ambiguity of the speech signal and constraints of context dynamically determine cognitive resources recruited during perception including focused attention, learning, and working memory. Theories of speech perception need to go beyond the current corticocentric approach in order to account for the intrinsic dynamics of the auditory encoding of speech. In doing so, this may provide new insights into ways in which hearing disorders and loss may be treated either through augementation or

  11. Surfaces: processing, coating, decontamination, pollution, etc. Surface mastering to prevent component corrosion; Surfaces: traitement, revetements, decontamination, pollution, etc. Maitrise de la surface pour prevenir la corrosion des composants

    Energy Technology Data Exchange (ETDEWEB)

    Foucault, M. [Departement Corrosion Chimie, AREVA Centre Technique, BP 181, 71205 Le Creusot (France)

    2012-07-01

    In the primary and secondary circuits of nuclear Pressurized Water Reactors, AREVA uses several nickel-based alloys or austenitic stainless steels for the manufacture of safety components. The experience feedback of the last twenty years allows us to point out the major role hold by the component surface state in their life duration. In this paper, we present four examples of problem encountered and solved by a surface study and the definition and implementation of processes for the surface control of the repaired components. Then, we propose some ideas about the present needs in term of analysis means to improve the surface knowledge and control of the manufactured components. (author)

  12. Surface photo reaction processes using synchrotron radiation; Hoshako reiki ni yoru hyomenko hanno process

    Energy Technology Data Exchange (ETDEWEB)

    Imaizumi, Y. [Tohoku University, Sendai (Japan). Institute for Materials Research; Yoshigoe, A. [Toyohashi University of Technology, Aichi (Japan); Urisu, T. [Toyohashi University of Technology, Aichi (Japan). Institute for Molecular Science

    1997-08-20

    This paper introduces the surface photo reaction processes using synchrotron radiation, and its application. A synchrotron radiation process using soft X-rays contained in electron synchrotron radiated light as an excited light source has a possibility of high-resolution processing because of its short wave length. The radiated light can excite efficiently the electronic state of a substance, and can induce a variety of photochemical reactions. In addition, it can excite inner shell electrons efficiently. In the aspect of its application, it has been found that, if radiated light is irradiated on surfaces of solids under fluorine-based reaction gas or Cl2, the surfaces can be etched. This technology is utilized practically. With regard to radiated light excited CVD process, it may be said that anything that can be deposited by the ordinary plasma CVD process can be deposited. Its application to epitaxial crystal growth may be said a nano processing application in thickness direction, such as forming an ultra-lattice structure, the application being subjected to expectation. In micromachine fabricating technologies, a possibility is searched on application of a photo reaction process of the radiated light. 5 refs., 6 figs.

  13. Surface properties of activated carbon treated by cold plasma heating

    Energy Technology Data Exchange (ETDEWEB)

    Norikazu, Kurano [Shigematsu works Co. Ltd., 267 Yashita, Iwatsuki 3390046 (Japan); Yamada, Hiroshi [Shigematsu works Co. Ltd., 267 Yashita, Iwatsuki 3390046 (Japan); Yajima, Tatsuhiko [Faculty of Engineering, Saitama Institute of Technology, 1690 Fusoiji, Okabe 3690293 (Japan); Sugiyama, Kazuo [Faculty of Engineering, Saitama University, 255 Shimo-okubo, Sakura-Ku, Saitama 3388570 (Japan)]. E-mail: sugi@apc.saitama-u.ac.jp

    2007-03-12

    To modify the surface properties of activated carbon powders, we have applied the cold plasma treatment method. The cold plasma was used to be generated in the evacuated reactor vessel by 2.45 GHz microwave irradiation. In this paper, changes of surface properties such as distribution of acidic functional groups and roughness morphology were examined. By the cold plasma treatment, activated carbons with large specific surface area of ca. 2000 m{sup 2}/g or more could be prepared in a minute. The amount of every gaseous organic compound adsorbed on the unit gram of treated activated carbons was more increased that on the unit gram of untreated carbons. Especially, the adsorbed amount of carbon disulfide was remarkably increased even if it was compared by the amount per unit surface area. These results suggest that the surface property of the sample was modified by the plasma treatment. It became apparent by observing SEM photographs that dust and impure particles in macropores of activated carbons were far more reduced by the plasma treatment than by the conventional heating in an electric furnace under vacuum. In addition, a bubble-like surface morphology of the sample was observed by AEM measurement. The amount of acidic functional groups at the surface was determined by using the Boehm's titration method. Consequently, the increase of lactone groups and the decrease of carboxyl groups were also observed.

  14. Textural Analysis of Fatique Crack Surfaces: Image Pre-processing

    Directory of Open Access Journals (Sweden)

    H. Lauschmann

    2000-01-01

    Full Text Available For the fatique crack history reconstitution, new methods of quantitative microfractography are beeing developed based on the image processing and textural analysis. SEM magnifications between micro- and macrofractography are used. Two image pre-processing operatins were suggested and proved to prepare the crack surface images for analytical treatment: 1. Normalization is used to transform the image to a stationary form. Compared to the generally used equalization, it conserves the shape of brightness distribution and saves the character of the texture. 2. Binarization is used to transform the grayscale image to a system of thick fibres. An objective criterion for the threshold brightness value was found as that resulting into the maximum number of objects. Both methods were succesfully applied together with the following textural analysis.

  15. Particle surface area and bacterial activity in recirculating aquaculture systems

    DEFF Research Database (Denmark)

    Pedersen, Per Bovbjerg; von Ahnen, Mathis; Fernandes, Paulo

    2017-01-01

    Suspended particles in recirculating aquaculture systems (RAS) provide surface area that can be colonized by bacteria. More particles accumulate as the intensity of recirculation increases thus potentially increasing the bacterial carrying capacity of the systems. Applying a recent, rapid, culture...... but may provide significant surface area. Hence, the study substantiates that particles in RAS provide surface area supporting bacterial activity, and that particles play a key role in controlling the bacterial carrying capacity at least in less intensive RAS. Applying fast, culture-independent techniques......-independent fluorometric detection method (Bactiquant®) for measuring bacterial activity, the current study explored the relationship between total particle surface area (TSA, derived from the size distribution of particles >5 μm) and bacterial activity in freshwater RAS operated at increasing intensity of recirculation...

  16. Microbe-surface interactions in biofouling and biocorrosion processes.

    Science.gov (United States)

    Beech, Iwona B; Sunner, Jan A; Hiraoka, Kenzo

    2005-09-01

    The presence of microorganisms on material surfaces can have a profound effect on materials performance. Surface-associated microbial growth, i.e. a biofilm, is known to instigate biofouling. The presence of biofilms may promote interfacial physico-chemical reactions that are not favored under abiotic conditions. In the case of metallic materials, undesirable changes in material properties due to a biofilm (or a biofouling layer) are referred to as biocorrosion or microbially influenced corrosion (MIC). Biofouling and biocorrosion occur in aquatic and terrestrial habitats varying in nutrient content, temperature, pressure and pH. Interfacial chemistry in such systems reflects a wide variety of physiological activities carried out by diverse microbial populations thriving within biofilms. Biocorrosion can be viewed as a consequence of coupled biological and abiotic electron-transfer reactions, i.e. redox reactions of metals, enabled by microbial ecology. Microbially produced extracellular polymeric substances (EPS), which comprise different macromolecules, mediate initial cell adhesion to the material surface and constitute a biofilm matrix. Despite their unquestionable importance in biofilm development, the extent to which EPS contribute to biocorrosion is not well-understood. This review offers a current perspective on material/microbe interactions pertinent to biocorrosion and biofouling, with EPS as a focal point, while emphasizing the role atomic force spectroscopy and mass spectrometry techniques can play in elucidating such interactions.

  17. Dual Electrolytic Plasma Processing for Steel Surface Cleaning and Passivation

    Science.gov (United States)

    Yang, L.; Zhang, P.; Shi, J.; Liang, J.; Tian, W. B.; Zhang, Y. M.; Sun, Z. M.

    2017-10-01

    To remove the rust on rebars and passivate the fresh surfaces, electrodes reversing electrolytic plasma processing (EPP) was proposed and conducted in a 10 wt.% Na2CO3 aqueous solution. The morphology and the composition of the surface were investigated by SEM and XPS. Experimental results show that the rust on the surface was removed effectively by cathode EPP, and a passive film containing Cr2O3 was achieved by the succeeding anode EPP treatment, by a simple operation of reversing the bias. The corrosion resistance was evaluated in a 3.5 wt.% NaCl aqueous solution using an electrochemical workstation. In comparison, the corrosion resistance was improved by the succeeding anode EPP treatment, which is evidenced by a positive shift of the open-circuit potential, an increase in the electrochemical impedance representing the inner layer by 76.8% and the decrease in the corrosion current density by 49.6%. This is an effective and environment-friendly technique to clean and passivate rebars and similar steel materials.

  18. Fibroblast adhesion and activation onto micro-machined titanium surfaces.

    Science.gov (United States)

    Guillem-Marti, J; Delgado, L; Godoy-Gallardo, M; Pegueroles, M; Herrero, M; Gil, F J

    2013-07-01

    Surface modifications performed at the neck of dental implants, in the manner of micro-grooved surfaces, can reduce fibrous tissue encapsulation and prevent bacterial colonization, thereby improving fibrointegration and the formation of a biological seal. However, the applied procedures are technically complex and/or time consuming methods. The aim of this study was to analyse the fibroblast behaviour on modified titanium surfaces obtained, applying a simple and low-cost method. An array of titanium surfaces was obtained using a commercial computerized numerical control lathe, modifying the feed rate and the cutting depth. To elucidate the potential ability of the generated surfaces to activate connective tissue cells, a thorough gene (by real time - qPCR) and protein (by western blot or zymography) expression and cellular response characterization (cell morphology, cell adhesion and cell activation by secreting extracellular matrix (ECM) components and their enzyme regulators) was performed. Micro-grooved surfaces have statistically significant differences in the groove's width (approximately 10, 50 and 100 μm) depending on the applied advancing fixed speed. Field emission scanning electron microscopy images showed that fibroblasts oriented along the generated grooves, but they were only entirely accommodated on the wider grooves (≥50 μm). Micro-grooved surfaces exhibited an earlier cell attachment and activation, as seen by collagen Iα1 and fibronectin deposition and activation of ECM remodelling enzymes, compared with the other surfaces. However, fibroblasts could remain in an activated state on narrower surfaces (fibrotic response. © 2012 John Wiley & Sons A/S.

  19. Land use and surface process domains on alpine hillslopes

    Science.gov (United States)

    Kuhn, Nikolaus J.; Caviezel, Chatrina; Hunziker, Matthias

    2015-04-01

    Shrubs and trees are generally considered to protect hillslopes from erosion. As a consequence, shrub encroachment on mountain pastures after abandoning grazing is not considered a threat to soils. However, the abandonment of mown or grazed grasslands causes a shift in vegetation composition and thus a change in landscape ecology and geomorphology. On many alpine slopes, current changes in land use and vegetation cover are accompanied by climate change, potentially generating a new geomorphic regime. Most of the debate focuses on the effect of land abandonment on water erosion rates. Generally, an established perennial vegetation cover improves the mechanical anchoring of the soil and the regulation of the soil water budget, including runoff generation and erosion. However, changing vegetation composition affects many other above- and below-ground properties like root density, -diversity and -geometry, soil structure, pore volume and acidity. Each combination of these properties can lead to a distinct scenario of dominating surface processes, often not reflected by common erosion risk assessment procedures. The study of soil properties along a chronosequence of green alder (alnusviridis) encroachment on the Unteralptal in central Switzerland reveals that shrub encroachment changes soil and vegetation properties towards an increase of resistance to run-off related erosion processes, but a decrease of slope stability against shallow landslides. The latter are a particular threat because of the currently increasing frequency of slide-triggering high magnitude rainfalls. The potential change of process domain on alpine pastures highlights the need for a careful use of erosion models when assessing future land use and climate scenarios. In mountains, but also other intensively managed agricultural landscapes, risk assessment without the appropriate reflection on the shifting relevance of surface processes carries the risk of missing future threats to environmental

  20. Active voltammetric microsensors with neural signal processing.

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, M. C.

    1998-12-11

    Many industrial and environmental processes, including bioremediation, would benefit from the feedback and control information provided by a local multi-analyte chemical sensor. For most processes, such a sensor would need to be rugged enough to be placed in situ for long-term remote monitoring, and inexpensive enough to be fielded in useful numbers. The multi-analyte capability is difficult to obtain from common passive sensors, but can be provided by an active device that produces a spectrum-type response. Such new active gas microsensor technology has been developed at Argonne National Laboratory. The technology couples an electrocatalytic ceramic-metallic (cermet) microsensor with a voltammetric measurement technique and advanced neural signal processing. It has been demonstrated to be flexible, rugged, and very economical to produce and deploy. Both narrow interest detectors and wide spectrum instruments have been developed around this technology. Much of this technology's strength lies in the active measurement technique employed. The technique involves applying voltammetry to a miniature electrocatalytic cell to produce unique chemical ''signatures'' from the analytes. These signatures are processed with neural pattern recognition algorithms to identify and quantify the components in the analyte. The neural signal processing allows for innovative sampling and analysis strategies to be employed with the microsensor. In most situations, the whole response signature from the voltammogram can be used to identify, classify, and quantify an analyte, without dissecting it into component parts. This allows an instrument to be calibrated once for a specific gas or mixture of gases by simple exposure to a multi-component standard rather than by a series of individual gases. The sampled unknown analytes can vary in composition or in concentration, the calibration, sensing, and processing methods of these active voltammetric microsensors can

  1. Active voltammetric microsensors with neural signal processing

    Science.gov (United States)

    Vogt, Michael C.; Skubal, Laura R.

    1999-02-01

    Many industrial and environmental processes, including bioremediation, would benefit from the feedback and control information provided by a local multi-analyte chemical sensor. For most processes, such a sensor would need to be rugged enough to be placed in situ for long-term remote monitoring, and inexpensive enough to be fielded in useful numbers. The multi-analyte capability is difficult to obtain from common passive sensors, but can be provided by an active device that produces a spectrum-type response. Such new active gas microsensor technology has been developed at Argonne National Laboratory. The technology couples an electrocatalytic ceramic-metallic (cermet) microsensor with a voltammetric measurement technique and advanced neural signal processing. It has been demonstrated to be flexible, rugged, and very economical to produce and deploy. Both narrow interest detectors and wide spectrum instruments have been developed around this technology. Much of this technology's strength lies in the active measurement technique employed. The technique involves applying voltammetry to a miniature electrocatalytic cell to produce unique chemical 'signatures' from the analytes. These signatures are processed with neural pattern recognition algorithms to identify and quantify the components in the analyte. The neural signal processing allows for innovative sampling and analysis strategies to be employed with the microsensor. In most situations, the whole response signature from the voltammogram can be used to identify, classify, and quantify an analyte, without dissecting it into component parts. This allows an instrument to be calibrated once for a specific gas or mixture of gases by simple exposure to a multi-component standard rather than by a series of individual gases. The sampled unknown analytes can vary in composition or in concentration; the calibration, sensing, and processing methods of these active voltammetric microsensors can detect, recognize, and

  2. Occurrence of Surface Active Agents in the Environment

    Directory of Open Access Journals (Sweden)

    Ewa Olkowska

    2014-01-01

    Full Text Available Due to the specific structure of surfactants molecules they are applied in different areas of human activity (industry, household. After using and discharging from wastewater treatment plants as effluent stream, surface active agents (SAAs are emitted to various elements of the environment (atmosphere, waters, and solid phases, where they can undergo numerous physic-chemical processes (e.g., sorption, degradation and freely migrate. Additionally, SAAs present in the environment can be accumulated in living organisms (bioaccumulation, what can have a negative effect on biotic elements of ecosystems (e.g., toxicity, disturbance of endocrine equilibrium. They also cause increaseing solubility of organic pollutants in aqueous phase, their migration, and accumulation in different environmental compartments. Moreover, surfactants found in aerosols can affect formation and development of clouds, which is associated with cooling effect in the atmosphere and climate changes. The environmental fate of SAAs is still unknown and recognition of this problem will contribute to protection of living organisms as well as preservation of quality and balance of various ecosystems. This work contains basic information about surfactants and overview of pollution of different ecosystems caused by them (their classification and properties, areas of use, their presence, and behavior in the environment.

  3. Investigation of ammonia air-surface exchange processes in a ...

    Science.gov (United States)

    Recent assessments of atmospheric deposition in North America note the increasing importance of reduced (NHx = NH3 + NH4+) forms of nitrogen (N) relative to oxidized forms. This shift in in the composition of inorganic nitrogen deposition has both ecological and policy implications. Deposition budgets developed from inferential models applied at the landscape scale, as well as regional and global chemical transport models, indicate that NH3 dry deposition contributes a significant portion of inorganic N deposition in many areas. However, the bidirectional NH3 flux algorithms employed in these models have not been extensively evaluated for North American conditions (e.g, atmospheric chemistry, meteorology, biogeochemistry). Further understanding of the processes controlling NH3 air-surface exchange in natural systems is critically needed. Based on preliminary results from the Southern Appalachian Nitrogen Deposition Study (SANDS), this presentation examines processes of NH3 air-surface exchange in a deciduous montane forest at the Coweeta Hydrologic Laboratory in western North Carolina. A combination of measurements and modeling are used to investigate net fluxes of NH3 above the forest and sources and sinks of NH3 within the canopy and forest floor. Measurements of biogeochemical NH4+ pools are used to characterize emission potential and NH3 compensation points of canopy foliage (i.e., green vegetation), leaf litter, and soil and their relation to NH3 fluxes

  4. Process for growing a film epitaxially upon an oxide surface and structures formed with the process

    Science.gov (United States)

    McKee, Rodney A.; Walker, Frederick J.

    1995-01-01

    A process and structure wherein a film comprised of a perovskite or a spinel is built epitaxially upon a surface, such as an alkaline earth oxide surface, involves the epitaxial build up of alternating constituent metal oxide planes of the perovskite or spinel. The first layer of metal oxide built upon the surface includes a metal element which provides a small cation in the crystalline structure of the perovskite or spinel, and the second layer of metal oxide built upon the surface includes a metal element which provides a large cation in the crystalline structure of the perovskite or spinel. The layering sequence involved in the film build up reduces problems which would otherwise result from the interfacial electrostatics at the first atomic layers, and these oxides can be stabilized as commensurate thin films at a unit cell thickness or grown with high crystal quality to thicknesses of 0.5-0.7 .mu.m for optical device applications.

  5. The detection of intestinal spike activity on surface electroenterograms

    Energy Technology Data Exchange (ETDEWEB)

    Ye-Lin, Y; Garcia-Casado, J; Martinez-de-Juan, J L; Prats-Boluda, G [Instituto interuniversitario de investigacion en bioingenierIa y tecnologIa orientada al ser humano (I3BH), Universidad Politecnica de Valencia, Camino de Vera, s/n, Ed. 8E, Acceso N, 2a, planta 46022 Valencia (Spain); Ponce, J L [Department of Surgery, Hospital Universitario La Fe de Valencia, Avenida Campanar n0. 51, 46009 Valencia (Spain)], E-mail: yiye@eln.upv.es, E-mail: jgarciac@eln.upv.es, E-mail: jlmartinez@eln.upv.es, E-mail: geprabo@eln.upv.es, E-mail: drjlponce@ono.com

    2010-02-07

    Myoelectrical recording could provide an alternative technique for assessing intestinal motility, which is a topic of great interest in gastroenterology since many gastrointestinal disorders are associated with intestinal dysmotility. The pacemaker activity (slow wave, SW) of the electroenterogram (EEnG) has been detected in abdominal surface recordings, although the activity related to bowel contractions (spike bursts, SB) has to date only been detected in experimental models with artificially favored electrical conductivity. The aim of the present work was to assess the possibility of detecting SB activity in abdominal surface recordings under physiological conditions. For this purpose, 11 recording sessions of simultaneous internal and external myolectrical signals were conducted on conscious dogs. Signal analysis was carried out in the spectral domain. The results show that in periods of intestinal contractile activity, high-frequency components of EEnG signals can be detected on the abdominal surface in addition to SW activity. The energy between 2 and 20 Hz of the surface myoelectrical recording presented good correlation with the internal intestinal motility index (0.64 {+-} 0.10 for channel 1 and 0.57 {+-} 0.11 for channel 2). This suggests that SB activity can also be detected in canine surface EEnG recording.

  6. The detection of intestinal spike activity on surface electroenterograms

    International Nuclear Information System (INIS)

    Ye-Lin, Y; Garcia-Casado, J; Martinez-de-Juan, J L; Prats-Boluda, G; Ponce, J L

    2010-01-01

    Myoelectrical recording could provide an alternative technique for assessing intestinal motility, which is a topic of great interest in gastroenterology since many gastrointestinal disorders are associated with intestinal dysmotility. The pacemaker activity (slow wave, SW) of the electroenterogram (EEnG) has been detected in abdominal surface recordings, although the activity related to bowel contractions (spike bursts, SB) has to date only been detected in experimental models with artificially favored electrical conductivity. The aim of the present work was to assess the possibility of detecting SB activity in abdominal surface recordings under physiological conditions. For this purpose, 11 recording sessions of simultaneous internal and external myolectrical signals were conducted on conscious dogs. Signal analysis was carried out in the spectral domain. The results show that in periods of intestinal contractile activity, high-frequency components of EEnG signals can be detected on the abdominal surface in addition to SW activity. The energy between 2 and 20 Hz of the surface myoelectrical recording presented good correlation with the internal intestinal motility index (0.64 ± 0.10 for channel 1 and 0.57 ± 0.11 for channel 2). This suggests that SB activity can also be detected in canine surface EEnG recording.

  7. Measurements of radon progeny activity on typical indoor surfaces

    International Nuclear Information System (INIS)

    Knutson, E.O.; Gogolak, C.V.; Klemic, G.

    1992-01-01

    A number of studies aimed at defining how well radon progeny on surfaces can be measured, information that is needed in order to test physical/mathematical models governing indoor radon progeny behaviour, are described. One experiment compared the decomposition on to different surfaces. Only relatively small differences were found among metal, filter paper, broadcloth, corduroy fabric, vinyl wallpaper, glass, and latex paint, but polyethylene film collected two to four times as much as the others, due most likely to electrostatic charge on the plastic surface. Another experiment compared the gamma and gross alpha count methods of measuring surface activity for metal, filter paper, broadcloth and corduroy surfaces. No difference for the surfaces tested was found from which it is concluded that, even for rougher surfaces, progeny atoms deposit mainly on the outer layers. A final experiment compared in situ and surrogate-surface methods for measuring surface deposition. For most tests, the two methods agreed within 30%, and the average ratio was not significantly different from unity. 210 Po is a complication in the in situ method. An unexpected location effect was found in the experiments conducted in houses with high radon concentrations: the deposition on the ceiling was higher than on the surfaces. (author)

  8. Potential Biosignificant Interest and Surface Activity of Efficient Heterocyclic Derivatives.

    Science.gov (United States)

    El-Sayed, Refat; Althagafi, Ismail

    2016-01-01

    Some functionalized pyridine and fused system derivatives were synthesized using enaminonitrile derivative 5 as a starting material for the reaction, with various reagents under different conditions. Propoxylation of these compounds using different moles of propylene oxide (3, 5 and 7 moles) leads to a novel group of surface active agents. The antimicrobial and surface activities of the synthesized compounds were investigated. Most of the evaluated compounds proved to be active as antibacterial and antifungal agents and showed good surface activity, which makes them suitable for diverse applications such as the manufacturing of emulsifiers, cosmetics, drugs, pesticides, etc. Additionally, biodegradation testing exhibits significant breakdown within six to seven days, and hence, lowers the toxicity to human beings and becomes environmentally friendly.

  9. Surface activity, lipid profiles and their implications in cervical cancer.

    Directory of Open Access Journals (Sweden)

    Preetha A

    2005-01-01

    Full Text Available Background: The profiles of lipids in normal and cancerous tissues may differ revealing information about cancer development and progression. Lipids being surface active, changes in lipid profiles can manifest as altered surface activity profiles. Langmuir monolayers offer a convenient model for evaluating surface activity of biological membranes. Aims: The aims of this study were to quantify phospholipids and their effects on surface activity of normal and cancerous human cervical tissues as well as to evaluate the role of phosphatidylcholine (PC and sphingomyelin (SM in cervical cancer using Langmuir monolayers. Methods and Materials: Lipid quantification was done using thin layer chromatography and phosphorus assay. Surface activity was evaluated using Langmuir monolayers. Monolayers were formed on the surface of deionized water by spreading tissue organic phase corresponding to 1 mg of tissue and studying their surface pressure-area isotherms at body temperature. The PC and SM contents of cancerous human cervical tissues were higher than those of the normal human cervical tissues. Role of PC and SM were evaluated by adding varying amounts of these lipids to normal cervical pooled organic phase. Statistical analysis: Student′s t-test (p < 0.05 and one-way analysis of variance (ANOVA was used. Results: Our results reveals that the phosphatidylglycerol level in cancerous cervical tissue was nearly five folds higher than that in normal cervical tissue. Also PC and sphingomyelin SM were found to be the major phospholipid components in cancerous and normal cervical tissues respectively. The addition of either 1.5 µg DPPC or 0.5 µg SM /mg of tissue to the normal organic phase changed its surface activity profile to that of the cancerous tissues. Statistically significant surface activity parameters showed that PC and SM have remarkable roles in shifting the normal cervical lipophilic surface activity towards that of cancerous lipophilic

  10. MarsSI: Martian surface data processing information system

    Science.gov (United States)

    Quantin-Nataf, C.; Lozac'h, L.; Thollot, P.; Loizeau, D.; Bultel, B.; Fernando, J.; Allemand, P.; Dubuffet, F.; Poulet, F.; Ody, A.; Clenet, H.; Leyrat, C.; Harrisson, S.

    2018-01-01

    MarsSI (Acronym for Mars System of Information, https://emars.univ-lyon1.fr/MarsSI/, is a web Geographic Information System application which helps managing and processing martian orbital data. The MarsSI facility is part of the web portal called PSUP (Planetary SUrface Portal) developed by the Observatories of Paris Sud (OSUPS) and Lyon (OSUL) to provide users with efficient and easy access to data products dedicated to the martian surface. The portal proposes 1) the management and processing of data thanks to MarsSI and 2) the visualization and merging of high level (imagery, spectral, and topographic) products and catalogs via a web-based user interface (MarsVisu). The portal PSUP as well as the facility MarsVisu is detailed in a companion paper (Poulet et al., 2018). The purpose of this paper is to describe the facility MarsSI. From this application, users are able to easily and rapidly select observations, process raw data via automatic pipelines, and get back final products which can be visualized under Geographic Information Systems. Moreover, MarsSI also contains an automatic stereo-restitution pipeline in order to produce Digital Terrain Models (DTM) on demand from HiRISE (High Resolution Imaging Science Experiment) or CTX (Context Camera) pair-images. This application is funded by the European Union's Seventh Framework Programme (FP7/2007-2013) (ERC project eMars, No. 280168) and has been developed in the scope of Mars, but the design is applicable to any other planetary body of the solar system.

  11. High surface area microporous activated carbons prepared from Fox nut (Euryale ferox) shell by zinc chloride activation

    International Nuclear Information System (INIS)

    Kumar, Arvind; Mohan Jena, Hara

    2015-01-01

    Graphical abstract: - Highlights: • Activated carbons have been prepared from Fox nutshell with chemical activation using ZnCl 2 . • The thermal behavior of the raw material and impregnated raw material has been carried out by thermogravimetric analysis. • The characterizations of the prepared activated carbons have been determined by nitrogen adsorption–desorption isotherms, FTIR, XRD, and FESEM. • The BET surface area and total pore volume of prepared activated carbon has been obtained as 2869 m 2 /g, 2124 m 2 /g, and 1.96 cm 3 /g, respectively. • The microporous surface area, micropore volume, and microporosity percentage of prepared activated carbon has been obtained as 2124 m 2 /g, 1.68 cm 3 /g, and 85.71%, respectively. - Abstract: High surface area microporous activated carbon has been prepared from Fox nutshell (Euryale ferox) by chemical activation with ZnCl 2 as an activator. The process has been conducted at different impregnation (ZnCl 2 /Fox nutshell) ratios (1–2.5) and carbonization temperatures (500–700 °C). The thermal decomposition behavior of Fox nutshell and impregnated Fox nutshell has been carried out by thermogravimetric analysis. The pore properties including the BET surface area, micropore surface area, micropore volume, and pore size distribution of the activated carbons have been determined by nitrogen adsorption–desorption isotherms at −196 °C using the BET, t-plot method, DR, and BJH methods. The BET surface area, the microporous surface area, total pore volume, and micropore volume have been obtained as 2869 m 2 /g, 2124 m 2 /g, 1.96 cm 3 /g, and 1.68 cm 3 /g, respectively, and the microporosity percentage of the prepared activated carbon is 85.71%. The prepared activated carbons have been also characterized with instrumental methods such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM).

  12. Comparison of deposited surface area of airborne ultrafine particles generated from two welding processes.

    Science.gov (United States)

    Gomes, J F; Albuquerque, P C; Miranda, Rosa M; Santos, Telmo G; Vieira, M T

    2012-09-01

    This article describes work performed on the assessment of the levels of airborne ultrafine particles emitted in two welding processes metal-active gas (MAG) of carbon steel and friction-stir welding (FSW) of aluminium in terms of deposited area in alveolar tract of the lung using a nanoparticle surface area monitor analyser. The obtained results showed the dependence from process parameters on emitted ultrafine particles and clearly demonstrated the presence of ultrafine particles, when compared with background levels. The obtained results showed that the process that results on the lower levels of alveolar-deposited surface area is FSW, unlike MAG. Nevertheless, all the tested processes resulted in important doses of ultrafine particles that are to be deposited in the human lung of exposed workers.

  13. Surface modification of food contact materials for processing and packaging applications

    Science.gov (United States)

    Barish, Jeffrey A.

    This body of work investigates various techniques for the surface modification of food contact materials for use in food packaging and processing applications. Nanoscale changes to the surface of polymeric food packaging materials enables changes in adhesion, wettability, printability, chemical functionality, and bioactivity, while maintaining desirable bulk properties. Polymer surface modification is used in applications such as antimicrobial or non-fouling materials, biosensors, and active packaging. Non-migratory active packagings, in which bioactive components are tethered to the package, offer the potential to reduce the need for additives in food products while maintaining safety and quality. A challenge in developing non-migratory active packaging materials is the loss of biomolecular activity that can occur when biomolecules are immobilized. Polyethylene glycol (PEG), a biocompatible polymer, is grafted from the surface of ozone treated low-density polyethylene (LDPE) resulting in a surface functionalized polyethylene to which a range of amine-terminated bioactive molecules can be immobilized. The grafting of PEG onto the surface of polymer packaging films is accomplished by free radical graft polymerization, and to covalently link an amine-terminated molecule to the PEG tether, demonstrating that amine-terminated bioactive compounds (such as peptides, enzymes, and some antimicrobials) can be immobilized onto PEG-grafted LDPE in the development of non-migratory active packaging. Fouling on food contact surfaces during food processing has a significant impact on operating efficiency and can promote biofilm development. Processing raw milk on plate heat exchangers results in significant fouling of proteins as well as minerals, and is exacerbated by the wall heating effect. An electroless nickel coating is co-deposited with polytetrafluoroethylene onto stainless steel to test its ability to resist fouling on a pilot plant scale plate heat exchanger. Further

  14. Modeling Aspects Of Activated Sludge Processes Part I: Process Modeling Of Activated Sludge Facilitation And Sedimentation

    International Nuclear Information System (INIS)

    Ibrahim, H. I.; EI-Ahwany, A.H.; Ibrahim, G.

    2004-01-01

    Process modeling of activated sludge flocculation and sedimentation reviews consider the activated sludge floc characteristics such as: morphology viable and non-viable cell ratio density and water content, bio flocculation and its kinetics were studied considering the characteristics of bio flocculation and explaining theory of Divalent Cation Bridging which describes the major role of cations in bio flocculation. Activated sludge flocculation process modeling was studied considering mass transfer limitations from Clifft and Andrew, 1981, Benefild and Molz 1983 passing Henze 1987, until Tyagi 1996 and G. Ibrahim et aI. 2002. Models of aggregation and breakage of flocs were studied by Spicer and Pratsinis 1996,and Biggs 2002 Size distribution of floes influences mass transfer and biomass separation in the activated sludge process. Therefore, it is of primary importance to establish the role of specific process operation factors, such as sludge loading dynamic sludge age and dissolved oxygen, on this distribution with special emphasis on the formation of primary particles

  15. Optimization of vibratory welding process parameters using response surface methodology

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Pravin Kumar; Kumar, S. Deepak; Patel, D.; Prasad, S. B. [National Institute of Technology Jamshedpur, Jharkhand (India)

    2017-05-15

    The current investigation was carried out to study the effect of vibratory welding technique on mechanical properties of 6 mm thick butt welded mild steel plates. A new concept of vibratory welding technique has been designed and developed which is capable to transfer vibrations, having resonance frequency of 300 Hz, into the molten weld pool before it solidifies during the Shielded metal arc welding (SMAW) process. The important process parameters of vibratory welding technique namely welding current, welding speed and frequency of the vibrations induced in molten weld pool were optimized using Taguchi’s analysis and Response surface methodology (RSM). The effect of process parameters on tensile strength and hardness were evaluated using optimization techniques. Applying RSM, the effect of vibratory welding parameters on tensile strength and hardness were obtained through two separate regression equations. Results showed that, the most influencing factor for the desired tensile strength and hardness is frequency at its resonance value, i.e. 300 Hz. The micro-hardness and microstructures of the vibratory welded joints were studied in detail and compared with those of conventional SMAW joints. Comparatively, uniform and fine grain structure has been found in vibratory welded joints.

  16. Active surface model improvement by energy function optimization for 3D segmentation.

    Science.gov (United States)

    Azimifar, Zohreh; Mohaddesi, Mahsa

    2015-04-01

    This paper proposes an optimized and efficient active surface model by improving the energy functions, searching method, neighborhood definition and resampling criterion. Extracting an accurate surface of the desired object from a number of 3D images using active surface and deformable models plays an important role in computer vision especially medical image processing. Different powerful segmentation algorithms have been suggested to address the limitations associated with the model initialization, poor convergence to surface concavities and slow convergence rate. This paper proposes a method to improve one of the strongest and recent segmentation algorithms, namely the Decoupled Active Surface (DAS) method. We consider a gradient of wavelet edge extracted image and local phase coherence as external energy to extract more information from images and we use curvature integral as internal energy to focus on high curvature region extraction. Similarly, we use resampling of points and a line search for point selection to improve the accuracy of the algorithm. We further employ an estimation of the desired object as an initialization for the active surface model. A number of tests and experiments have been done and the results show the improvements with regards to the extracted surface accuracy and computational time of the presented algorithm compared with the best and recent active surface models. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Effects of Surface Treatment of Activated Carbon on Its Surface and Cr(VI) Adsorption Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Park, Soo Jin; Jang, Yu Sin [Advanced Materials Division., Korea Research Institute of Chimical Technology, Taejon (Korea)

    2001-04-01

    In this work, the effect of surface treatments on activated carbons (ACs) has been studied in the context of gas and liquid adsorption behaviors. The chemical solutions used in this experiment were 35% sodium hydroxide, and these were used for the acidic and basic treatments, respectively. The surface properties have been determined by pH, acid-base values, and FT-IR. The adsorption isotherms of Cr(VI) ion on activated carbons have been studied with the 5 mg/l concentration at ambient temperature. N{sub 2} adsorption isotherm characteristics, which include the specific surface area, micro pore volume, and microporosity, were determined by BET and Boer's-plot methods. In case of the acidic treatment of activated carbons, it was observed that the adsorption of Cr(VI) ion was more effective due to the increase acid value (or acidic functional group) of activated carbon surfaces. However, the basic treatment on activated carbons was caused no significant effects, probably due to the decreased specific surface area and total pore volume. 27 refs., 7 figs., 4 tabs.

  18. Broad beam ion sources and some surface processes

    International Nuclear Information System (INIS)

    Neumann, H.; Scholze, F.; Tarz, M.; Schindler, A.; Wiese, R.; Nestler, M.; Blum, T.

    2005-01-01

    Modern broad-beam multi-aperture ion sources are widely used in material and surface technology applications. Customizing the generated ion beam properties (i. e. the ion current density profile) for specific demands of the application is a main challenge in the improvement of the ion beam technologies. First we introduce ion sources based on different plasma excitation principles shortly. An overview of source plasma and ion beam measurement methods deliver input data for modelling methods. This beam profile modelling using numerical trajectory codes and the validation of the results by Faraday cup measurements as a basis for ion beam profile design are described. Furthermore possibilities for ex situ and in situ beam profile control are demonstrated, like a special method for in situ control of a linear ion source beam profile, a grid modification for circular beam profile design and a cluster principle for broad beam sources. By means of these methods, the beam shape may be adapted to specific technological demands. Examples of broad beam source application in ion beam figuring of optical surfaces, modification of stainless steel, photo voltaic processes and deposition of EUVL-multilayer stacks are finally presented. (Author)

  19. Use of Radiotracers to Study Surface Water Processes

    International Nuclear Information System (INIS)

    2015-03-01

    This publication represents a sound knowledge base for the conduct of radiotracer studies in the environment, with papers on radiotracer methodology, radiation protection and regulation, data analysis and modelling. Environmental case histories from five Member States - Australia, Brazil, France, the Republic of Korea and Sweden - provide information on conducting studies involving he use of radioactive tracers. These case histories are not meant as guidelines for preparing a field study but can rather serve as examples of the type, caution and extent of work involved in environmental studies using radiotracers. This publication can provide guidance for conducting potential future training events in the use of radioactive traces in the environment and can serve as a key reference to all concerned directly with surface water processes

  20. Linear response theory of activated surface diffusion with interacting adsorbates

    Energy Technology Data Exchange (ETDEWEB)

    Marti' nez-Casado, R. [Department of Chemistry, Imperial College London, South Kensington, London SW7 2AZ (United Kingdom); Sanz, A.S.; Vega, J.L. [Instituto de Fi' sica Fundamental, Consejo Superior de Investigaciones Cientificas, Serrano 123, 28006 Madrid (Spain); Rojas-Lorenzo, G. [Instituto Superior de Tecnologi' as y Ciencias Aplicadas, Ave. Salvador Allende, esq. Luaces, 10400 La Habana (Cuba); Instituto de Fi' sica Fundamental, Consejo Superior de Investigaciones Cienti' ficas, Serrano 123, 28006 Madrid (Spain); Miret-Artes, S., E-mail: s.miret@imaff.cfmac.csic.es [Instituto de Fi' sica Fundamental, Consejo Superior de Investigaciones Cienti' ficas, Serrano 123, 28006 Madrid (Spain)

    2010-05-12

    Graphical abstract: Activated surface diffusion with interacting adsorbates is analyzed within the Linear Response Theory framework. The so-called interacting single adsorbate model is justified by means of a two-bath model, where one harmonic bath takes into account the interaction with the surface phonons, while the other one describes the surface coverage, this leading to defining a collisional friction. Here, the corresponding theory is applied to simple systems, such as diffusion on flat surfaces and the frustrated translational motion in a harmonic potential. Classical and quantum closed formulas are obtained. Furthermore, a more realistic problem, such as atomic Na diffusion on the corrugated Cu(0 0 1) surface, is presented and discussed within the classical context as well as within the framework of Kramer's theory. Quantum corrections to the classical results are also analyzed and discussed. - Abstract: Activated surface diffusion with interacting adsorbates is analyzed within the Linear Response Theory framework. The so-called interacting single adsorbate model is justified by means of a two-bath model, where one harmonic bath takes into account the interaction with the surface phonons, while the other one describes the surface coverage, this leading to defining a collisional friction. Here, the corresponding theory is applied to simple systems, such as diffusion on flat surfaces and the frustrated translational motion in a harmonic potential. Classical and quantum closed formulas are obtained. Furthermore, a more realistic problem, such as atomic Na diffusion on the corrugated Cu(0 0 1) surface, is presented and discussed within the classical context as well as within the framework of Kramer's theory. Quantum corrections to the classical results are also analyzed and discussed.

  1. Active surface system for the new Sardinia Radiotelescope

    Science.gov (United States)

    Orfei, Alessandro; Morsiani, Marco; Zacchiroli, Giampaolo; Maccaferri, Giuseppe; Roda, Juri; Fiocchi, Franco

    2004-09-01

    In this paper we'll describe the active surface system that will be provided on the new Italian radiotelescope being in the phase of erection in the Sardinia Island. SRT (Sardinia Radiotelescope) will be a 64m shaped dish working up to 100GHz by exploiting the active surface facility designed by the authors. This facility will overcome the effects of gravity deformations on the antenna gain and will also be used to re-shape in a parabolic form the primary mirror, in order to avoid large phase error contribution on the antenna gain for the highest frequencies placed on the primary focus. Together with the description of the SRT system, a wide overview will be given regarding our previous installation of an active surface system, that can be seen like a prototype for SRT, mounted on the 32m dish of the Noto antenna.

  2. Improving Accuracy of Processing Through Active Control

    Directory of Open Access Journals (Sweden)

    N. N. Barbashov

    2016-01-01

    Full Text Available An important task of modern mathematical statistics with its methods based on the theory of probability is a scientific estimate of measurement results. There are certain costs under control, and under ineffective control when a customer has got defective products these costs are significantly higher because of parts recall.When machining the parts, under the influence of errors a range scatter of part dimensions is offset towards the tolerance limit. To improve a processing accuracy and avoid defective products involves reducing components of error in machining, i.e. to improve the accuracy of machine and tool, tool life, rigidity of the system, accuracy of the adjustment. In a given time it is also necessary to adapt machine.To improve an accuracy and a machining rate there, currently  become extensively popular various the in-process gaging devices and controlled machining that uses adaptive control systems for the process monitoring. Improving the accuracy in this case is compensation of a majority of technological errors. The in-cycle measuring sensors (sensors of active control allow processing accuracy improvement by one or two quality and provide a capability for simultaneous operation of several machines.Efficient use of in-cycle measuring sensors requires development of methods to control the accuracy through providing the appropriate adjustments. Methods based on the moving average, appear to be the most promising for accuracy control since they include data on the change in some last measured values of the parameter under control.

  3. Room temperature Cu-Cu direct bonding using surface activated bonding method

    International Nuclear Information System (INIS)

    Kim, T.H.; Howlader, M.M.R.; Itoh, T.; Suga, T.

    2003-01-01

    Thin copper (Cu) films of 80 nm thickness deposited on a diffusion barrier layered 8 in. silicon wafers were directly bonded at room temperature using the surface activated bonding method. A low energy Ar ion beam of 40-100 eV was used to activate the Cu surface prior to bonding. Contacting two surface-activated wafers enables successful Cu-Cu direct bonding. The bonding process was carried out under an ultrahigh vacuum condition. No thermal annealing was required to increase the bonding strength since the bonded interface was strong enough at room temperature. The chemical constitution of the Cu surface was examined by Auger electron spectroscope. It was observed that carbon-based contaminations and native oxides on copper surface were effectively removed by Ar ion beam irradiation for 60 s without any wet cleaning processes. An atomic force microscope study shows that the Ar ion beam process causes no surface roughness degradation. Tensile test results show that high bonding strength equivalent to bulk material is achieved at room temperature. The cross-sectional transmission electron microscope observations reveal the presence of void-free bonding interface without intermediate layer at the bonded Cu surfaces

  4. Multi-surface topography targeted plateau honing for the processing of cylinder liner surfaces of automotive engines

    Science.gov (United States)

    Lawrence, K. Deepak; Ramamoorthy, B.

    2016-03-01

    Cylinder bores of automotive engines are 'engineered' surfaces that are processed using multi-stage honing process to generate multiple layers of micro geometry for meeting the different functional requirements of the piston assembly system. The final processed surfaces should comply with several surface topographic specifications that are relevant for the good tribological performance of the engine. Selection of the process parameters in three stages of honing to obtain multiple surface topographic characteristics simultaneously within the specification tolerance is an important module of the process planning and is often posed as a challenging task for the process engineers. This paper presents a strategy by combining the robust process design and gray-relational analysis to evolve the operating levels of honing process parameters in rough, finish and plateau honing stages targeting to meet multiple surface topographic specifications on the final running surface of the cylinder bores. Honing experiments were conducted in three stages namely rough, finish and plateau honing on cast iron cylinder liners by varying four honing process parameters such as rotational speed, oscillatory speed, pressure and honing time. Abbott-Firestone curve based functional parameters (Rk, Rpk, Rvk, Mr1 and Mr2) coupled with mean roughness depth (Rz, DIN/ISO) and honing angle were measured and identified as the surface quality performance targets to be achieved. The experimental results have shown that the proposed approach is effective to generate cylinder liner surface that would simultaneously meet the explicit surface topographic specifications currently practiced by the industry.

  5. Enhancement of activated sludge disintegration and dewaterability by Fenton process

    Science.gov (United States)

    Heng, G. C.; Isa, M. H.

    2016-06-01

    Municipal and industrial wastewater treatment plants produce large amounts of sludge. This excess sludge is an inevitable drawback inherent to the activated sludge process. In this study, the waste activated sludge was obtained from the campus wastewater treatment plant at Universiti Teknologi PETRONAS (UTP), Malaysia. Fenton pretreatment was optimized by using the response surface methodology (RSM) to study the effects of three operating conditions including the dosage of H2O2 (g H2O2/kg TS), the molar ratio of H2O2/Fe2+ and reaction time. The optimum operating variables to achieve MLVSS removal 65%, CST reduction 28%, sCOD 11000 mg/L and EPS 500 mg/L were: 1000 g H2O2/kg TS, H2O2/Fe2+ molar ratio 70 and reaction time 45 min. Fenton process was proved to be able to enhance the sludge disintegration and dewaterability.

  6. Use of Natural Zeolite to Upgrade Activated Sludge Process

    Directory of Open Access Journals (Sweden)

    Hanife Büyükgüngör

    2003-01-01

    Full Text Available The objective of this study was to achieve better efficiency of phosphorus removal in an enhanced biological phosphorus removal process by upgrading the system with different amounts of natural zeolite addition. The system performance for synthetic wastewater containing different carbon sources applied at different initial concentrations of phosphorus, as well as for municipal wastewater, was investigated. Natural zeolite addition in the aerobic phase of the anaerobic/aerobic bioaugmented activated sludge system contributed to a significant improvement of phosphorus removal in systems with synthetic wastewater and fresh municipal wastewater. Improvement of phosphorus removal with regard to the control reactors was higher with the addition of 15 than with 5 g/L of natural zeolite. In reactors with natural zeolite addition with regard to the control reactors significantly decreased chemical oxygen demand, ammonium and nitrate, while higher increment and better-activated sludge settling were achieved, without changes in the pH-values of the medium. It was shown that the natural zeolite particles are suitable support material for the phosphate-accumulating bacteria Acinetobacter calcoaceticus (DSM 1532, which were adsorbed on the particle surface, resulting in increased biological activity of the system. The process of phosphorus removal in a system with bioaugmented activated sludge and natural zeolite addition consisted of: metabolic activity of activated sludge, phosphorus uptake by phosphate-accumulating bacteria adsorbed on the natural zeolite particles and suspended in solution, and phosphorus adsorption on the natural zeolite particles.

  7. Gestalten of today: early processing of visual contours and surfaces.

    Science.gov (United States)

    Kovács, I

    1996-12-01

    While much is known about the specialized, parallel processing streams of low-level vision that extract primary visual cues, there is only limited knowledge about the dynamic interactions between them. How are the fragments, caught by local analyzers, assembled together to provide us with a unified percept? How are local discontinuities in texture, motion or depth evaluated with respect to object boundaries and surface properties? These questions are presented within the framework of orientation-specific spatial interactions of early vision. Key observations of psychophysics, anatomy and neurophysiology on interactions of various spatial and temporal ranges are reviewed. Aspects of the functional architecture and possible neural substrates of local orientation-specific interactions are discussed, underlining their role in the integration of information across the visual field, and particularly in contour integration. Examples are provided demonstrating that global context, such as contour closure and figure-ground assignment, affects these local interactions. It is illustrated that figure-ground assignment is realized early in visual processing, and that the pattern of early interactions also brings about an effective and sparse coding of visual shape. Finally, it is concluded that the underlying functional architecture is not only dynamic and context dependent, but the pattern of connectivity depends as much on past experience as on actual stimulation.

  8. Active screen plasma nitriding enhances cell attachment to polymer surfaces

    International Nuclear Information System (INIS)

    Kaklamani, Georgia; Bowen, James; Mehrban, Nazia; Dong, Hanshan; Grover, Liam M.; Stamboulis, Artemis

    2013-01-01

    Active screen plasma nitriding (ASPN) is a well-established technique used for the surface modification of materials, the result of which is often a product with enhanced functional performance. Here we report the modification of the chemical and mechanical properties of ultra-high molecular weight poly(ethylene) (UHMWPE) using 80:20 (v/v) N 2 /H 2 ASPN, followed by growth of 3T3 fibroblasts on the treated and untreated polymer surfaces. ASPN-treated UHMWPE showed extensive fibroblast attachment within 3 h of seeding, whereas fibroblasts did not successfully attach to untreated UHMWPE. Fibroblast-coated surfaces were maintained for up to 28 days, monitoring their metabolic activity and morphology throughout. The chemical properties of the ASPN-treated UHMWPE surface were studied using X-ray photoelectron spectroscopy, revealing the presence of C-N, C=N, and C≡N chemical bonds. The elastic modulus, surface topography, and adhesion properties of the ASPN-treated UHMWPE surface were studied over 28 days during sample storage under ambient conditions and during immersion in two commonly used cell culture media.

  9. MICROORGANISMS’ SURFACE ACTIVE SUBSTANCES ROLE IN HYDROCARBONS BIODEGRADATION

    Directory of Open Access Journals (Sweden)

    Оlga Vasylchenko

    2012-09-01

    Full Text Available  Existing data and publications regarding oil, hydrocarbon biodegradation, metabolism, and bioremediation were analyzed. Search of hydrocarbon degrading bacteria which are producers of biosurfactants was provided, types of microbial surfactants and their physiological role were analyzed and ordered. The study of factors affecting the surface active properties of producers’ cultures was done.

  10. Identifying the Active Surfaces of Electrochemically Tuned LiCoO2 for Oxygen Evolution Reaction

    International Nuclear Information System (INIS)

    Lu, Zhiyi; Chen, Guangxu; Li, Yanbin; Wang, Haotian; Xie, Jin

    2017-01-01

    Identification of active sites for catalytic processes has both fundamental and technological implications for rational design of future catalysts. Herein, we study the active surfaces of layered lithium cobalt oxide (LCO) for the oxygen evolution reaction (OER) using the enhancement effect of electrochemical delithiation (De-LCO). Our theoretical results indicate that the most stable (0001) surface has a very large overpotential for OER independent of lithium content. In contrast, edge sites such as the nonpolar (1120) and polar (0112) surfaces are predicted to be highly active and dependent on (de)lithiation. The effect of lithium extraction from LCO on the surfaces and their OER activities can be understood by the increase of Co 4+ sites relative to Co 3+ and by the shift of active oxygen 2p states. Experimentally, it is demonstrated that LCO nanosheets, which dominantly expose the (0001) surface show negligible OER enhancement upon delithiation. However, a noticeable increase in OER activity (~0.1 V in overpotential shift at 10 mA cm –2 ) is observed for the LCO nanoparticles, where the basal plane is greatly diminished to expose the edge sites, consistent with the theoretical simulations. In addition, we find that the OER activity of De-LCO nanosheets can be improved if we adopt an acid etching method on LCO to create more active edge sites, which in turn provides a strong evidence for the theoretical indication.

  11. Preserving the Context of Interrupted Business Process Activities

    NARCIS (Netherlands)

    Bassil, S.; Rinderle, S.B.; Keller, R.; Reichert, M.U.; Kropf, P.G.

    2005-01-01

    The capability to safely interrupt business process activities is an important requirement for advanced process-aware information systems. Indeed, exceptions stemming from the application environment often appear while one or more application-related process activities are running. Safely

  12. Preserving the Context of Interrupted Business Process Activities

    NARCIS (Netherlands)

    Bassil, S.; Rinderle, S.B.; Keller, R.; Kropf, P.G.; Reichert, M.U.; Chen, C.S.; Filipe, J.; Seruca, I.; Cordeiro, J.

    2006-01-01

    The capability to safely interrupt business process activities is an important requirement for advanced process-aware information systems. Indeed, exceptions stemming from the application environment often appear while one or more application-related process activities are running. Safely

  13. Surface passivation process of compound semiconductor material using UV photosulfidation

    Science.gov (United States)

    Ashby, Carol I. H.

    1995-01-01

    A method for passivating compound semiconductor surfaces by photolytically disrupting molecular sulfur vapor with ultraviolet radiation to form reactive sulfur which then reacts with and passivates the surface of compound semiconductors.

  14. Surface morphology evolution in silicon during ion beam processing; TOPICAL

    International Nuclear Information System (INIS)

    Bedrossian P; Caturla, M; Diaz de la Rubia, T; Johnson, M

    1999-01-01

    of predictive process simulators. The results were then used to develop kinetic Monte Carlo simulations that, when coupled to molecular dynamics studies, could be used to study and compare the long time and length scale behavior of ion implanted silicon to the predictions of experiments. The results of these kinetic Monte Carlo simulations were validated with experimental data and then used to predict boron activation fractions during annealing of ion implanted silicon under conditions similar to those encountered in the semiconductor manufacturing environment. The success of the work and promise of the approach are reflected in the number of publication and in the fact that following completion of the project we signed a funds-in CRADA with Intel corporation and Applied Materials Corporation to continue the research

  15. Preparation, Surface and Pore Structure of High Surface Area Activated Carbon Fibers from Bamboo by Steam Activation

    Directory of Open Access Journals (Sweden)

    Xiaojun Ma

    2014-06-01

    Full Text Available High surface area activated carbon fibers (ACF have been prepared from bamboo by steam activation after liquefaction and curing. The influences of activation temperature on the microstructure, surface area and porosity were investigated. The results showed that ACF from bamboo at 850 °C have the maximum iodine and methylene blue adsorption values. Aside from the graphitic carbon, phenolic and carbonyl groups were the predominant functions on the surface of activated carbon fiber from bamboo. The prepared ACF from bamboo were found to be mainly type I of isotherm, but the mesoporosity presented an increasing trend after 700 °C. The surface area and micropore volume of samples, which were determined by application of the Brunauer-Emmett-Teller (BET and t-plot methods, were as high as 2024 m2/g and 0.569 cm3/g, respectively. It was also found that the higher activation temperature produced the more ordered microcrystalline structure of ACF from bamboo.

  16. Shewanella putrefaciens adhesion and biofilm formation on food processing surfaces

    DEFF Research Database (Denmark)

    Bagge, Dorthe; Hjelm, M.; Johansen, C.

    2001-01-01

    Laboratory model systems were developed for studying Shewanella putrefaciens adhesion and biofilm formation under batch and flow conditions. S. putrefaciens plays a major role in food spoilage and may cause microbially induced corrosion on steel surfaces. S. putrefaciens bacteria suspended in buf...... from surfaces, and indirect conductometry and found this combination sufficient to quantify bacteria on surfaces...

  17. Controlling hydrogenation activity and selectivity of bimetallic surfaces and catalysts

    Science.gov (United States)

    Murillo, Luis E.

    Studies of bimetallic systems are of great interest in catalysis due to the novel properties that they often show in comparison with the parent metals. The goals of this dissertation are: (1) to expand the studies of self-hydrogenation and hydrogenation reactions on bimetallic surfaces under ultra high vacuum conditions (UHV) using different hydrocarbon as probe molecules; (2) to attempt to correlate the surface science findings with supported catalyst studies under more realistic conditions; and (3) to investigate the competitive hydrogenation of C=C versus C=O bonds on Pt(111) modified by different 3d transition metals. Hydrogenation studies using temperature programmed desorption (TPD) on Ni/Pt(111) bimetallic surfaces have demonstrated an enhancement in the low temperature hydrogenation activity relative to that of clean Pt(111). This novel hydrogenation pathway can be achieved under UHV conditions by controlling the structures of the bimetallic surfaces. A low temperature hydrogenation activity of 1-hexene and 1-butene has been observed on a Pt-Ni-Pt(111) subsurface structure, where Ni atoms are mainly present on the second layer of the Pt(111) single crystal. These results are in agreement with previous studies of self-hydrogenation and hydrogenation of cyclohexene. However, a much higher dehydrogenation activity is observed in the reaction of cyclohexene to produce benzene, demonstrating that the hydrocarbon structure has an effect on the reaction pathways. On the other hand, self-hydrogenation of 1-butene is not observed on the Pt-Ni-Pt(111) surface, indicating that the chain length (or molecular weight) has a significant effect on the selfhydrogenation activity. The gas phase reaction of cyclohexene on Ni/Pt supported on alumina catalysts has also shown a higher self-hydrogenation activity in comparison with the same reaction performed on supported monometallic catalysts. The effects of metal loading and impregnation sequence of the metal precursors are

  18. Patched bimetallic surfaces are active catalysts for ammonia decomposition.

    Science.gov (United States)

    Guo, Wei; Vlachos, Dionisios G

    2015-10-07

    Ammonia decomposition is often used as an archetypical reaction for predicting new catalytic materials and understanding the very reason of why some reactions are sensitive on material's structure. Core-shell or surface-segregated bimetallic nanoparticles expose outstanding activity for many heterogeneously catalysed reactions but the reasons remain elusive owing to the difficulties in experimentally characterizing active sites. Here by performing multiscale simulations in ammonia decomposition on various nickel loadings on platinum (111), we show that the very high activity of core-shell structures requires patches of the guest metal to create and sustain dual active sites: nickel terraces catalyse N-H bond breaking and nickel edge sites drive atomic nitrogen association. The structure sensitivity on these active catalysts depends profoundly on reaction conditions due to kinetically competing relevant elementary reaction steps. We expose a remarkable difference in active sites between transient and steady-state studies and provide insights into optimal material design.

  19. Acoustic emission-based in-process monitoring of surface generation in robot-assisted polishing

    DEFF Research Database (Denmark)

    Pilny, Lukas; Bissacco, Giuliano; De Chiffre, Leonardo

    2016-01-01

    The applicability of acoustic emission (AE) measurements for in-process monitoring of surface generation in the robot-assisted polishing (RAP) was investigated. Surface roughness measurements require interruption of the process, proper surface cleaning and measurements that sometimes necessitate...... automatic detection of optimal process endpoint allow intelligent process control, creating fundamental elements in development of robust fully automated RAP process for its widespread industrial application....... removal of the part from the machine tool. In this study, stabilisation of surface roughness during polishing rotational symmetric surfaces by the RAP process was monitored by AE measurements. An AE sensor was placed on a polishing arm in direct contact with a bonded abrasive polishing tool...

  20. Using OSL dating to quantify rates of Earth surface processes

    Science.gov (United States)

    Rhodes, E. J.; Rittenour, T. M.

    2010-12-01

    In Optically Stimulated Luminescence (OSL), the dating signal is reset when mineral grains are exposed to light or heat, and gradually rebuilds during subsequent burial by interaction with ionising radiation. Quartz and feldspar provide useful OSL signals demonstrating rapid signal reduction in only seconds of light exposure. Age estimates ranging from under 1 year to around 200,000 years can be determined for a wide range of sedimentary contexts, including dunes, marine deposits, fluvial and glacial environments, and recent developments provide the framework for low temperature thermochronometric applications on timescales comparable with rapid climate fluctuations. In this presentation, we explore the range of applications for determining rates of Earth surface processes using OSL. We examine technical limitations, and provide a framework for overcoming current difficulties experienced in several specific regions and contexts. We will focus on OSL dating applications to glacigenic and fluvial records, along with use of the technique in tectonic and paleoseismic contexts. In many ways, these represent the most challenging environments for OSL; rapid high energy deposition is associated with incomplete signal zeroing, and the characteristics of quartz in many of these environments make it difficult to derive precise age estimates using this mineral. We will introduce innovative methods to overcome these limitations, both existing and those under development.

  1. Air plasma processing of poly(methyl methacrylate) micro-beads: Surface characterisations

    International Nuclear Information System (INIS)

    Liu Chaozong; Cui Naiyi; Osbeck, Susan; Liang He

    2012-01-01

    Highlights: ► PMMA micro-beads were processed using a rotary air plasma reactor. ► Surface chemistry and surface texture of PMMA micro-beads were characterised. ► Surface wettability was evaluated using “floating” water contact angle method. ► Surface oxidation and texture changes induced by air plasma attributed to the improvement of surface wettability. - Abstract: This paper reports the surface processing of poly(methyl methacrylate) (PMMA) micro-beads by using a rotary air plasma reactor, and its effects on surface properties. The surface properties, including surface wettability, surface chemistry and textures of the PMMA beads, were characterised. It was observed that the air plasma processing can improve the surface wettability of the PMMA microbeads significantly. A 15 min plasma processing can reduce the surface water contact angle of PMMA beads to about 50° from its original value of 80.3°. This was accompanied by about 8% increase in surface oxygen concentration as confirmed by XPS analysis. The optical profilometry examination revealed the air plasma processing resulted in a rougher surface that has a “delicate” surface texture. It is concluded that the surface chemistry and texture, induced by air plasma processing, co-contributed to the surface wettability improvement of PMMA micro-beads.

  2. Influence of milling process in the surface energy of glass tile frits

    International Nuclear Information System (INIS)

    Tamayo, A.; Rubio, F.; Otero, J. L.; Rubio, J.

    2013-01-01

    In this work has been studied the influence of the milling process of two ceramic frits used in the ceramic tile industry. Both glass frits were of similar chemical composition changing SiO 2 by 5% of B 2 O 3 and both of them were water or dry milled. Glass frit surfaces were characterized by FT-IR, Karl-Fischer (K-F) titration and Inverse Gas Chromatography at Infinite Dilution (IGC-ID). By K-F titration it was observed that water milled frits presented 28 and 26 OH groups for 100 A 2 if they do not contain or contain boron, respectively. These surface changes are also observed by IGC-ID. Thus, the glass frit without boron and dry milled presented the highest dispersive surface energy (44 mJ.m - 2) and the less acidic constant (0.13 kJ.mol - 1). Both glass frits are amphoteric with acidic and base surface active sites, and that frit without boron presents the higher basicity. Milling process influences in the acid-base surface characteristics of both frits by increasing the basicity for the one without boron and increasing for the other one. This has been assigned to the different location of hydroxyl groups where the higher interaction is the one that does not contain boron and dry milled as K-F results. (Author)

  3. Microstructure and surface properties of lignocellulosic-based activated carbons

    International Nuclear Information System (INIS)

    González-García, P.; Centeno, T.A.; Urones-Garrote, E.; Ávila-Brande, D.; Otero-Díaz, L.C.

    2013-01-01

    Highlights: ► Activated carbons were produced by KOH activation at 700 °C. ► The observed nanostructure consists of highly disordered graphene–like layers with sp 2 bond content ≈ 95%. ► Textural parameters show high surface area (≈ 1000 m 2 /g) and pore width of 1.3–1.8 nm. ► Specific capacitance reaches values as high as 161 F/g. - Abstract: Low cost activated carbons have been produced via chemical activation, by using KOH at 700 °C, from the bamboo species Guadua Angustifolia and Bambusa Vulgaris Striata and the residues from shells of the fruits of Castanea Sativa and Juglans Regia as carbon precursors. The scanning electron microscopy micrographs show the conservation of the precursor shape in the case of the Guadua Angustifolia and Bambusa Vulgaris Striata activated carbons. Transmission electron microscopy analyses reveal that these materials consist of carbon platelet–like particles with variable length and thickness, formed by highly disordered graphene–like layers with sp 2 content ≈ 95% and average mass density of 1.65 g/cm 3 (25% below standard graphite). Textural parameters indicate a high porosity development with surface areas ranging from 850 to 1100 m 2 /g and average pore width centered in the supermicropores range (1.3–1.8 nm). The electrochemical performance of the activated carbons shows specific capacitance values at low current density (1 mA/cm 2 ) as high as 161 F/g in the Juglans Regia activated carbon, as a result of its textural parameters and the presence of pseudocapacitance derived from surface oxygenated acidic groups (mainly quinones and ethers) identified in this activated carbon.

  4. Preferences for Deep-Surface Learning: A Vocational Education Case Study Using a Multimedia Assessment Activity

    Science.gov (United States)

    Hamm, Simon; Robertson, Ian

    2010-01-01

    This research tests the proposition that the integration of a multimedia assessment activity into a Diploma of Events Management program promotes a deep learning approach. Firstly, learners' preferences for deep or surface learning were evaluated using the revised two-factor Study Process Questionnaire. Secondly, after completion of an assessment…

  5. Photochemical Transformation Processes in Sunlit Surface Waters (Invited)

    Science.gov (United States)

    Vione, D.

    2013-12-01

    Photochemical reactions are major processes in the transformation of hardly biodegradable xenobiotics in surface waters. They are usually classified into direct photolysis and indirect or sensitised degradation. Direct photolysis requires xenobiotic compounds to absorb sunlight, and to get transformed as a consequence. Sensitised transformation involves reaction with transient species (e.g. °OH, CO3-°, 1O2 and triplet states of chromophoric dissolved organic matter, 3CDOM*), photogenerated by so-called photosensitisers (nitrate, nitrite and CDOM). CDOM is a major photosensitiser: is it on average the main source of °OH (and of CO3-° as a consequence, which is mainly produced upon oxidation by °OH of carbonate and bicarbonate) and the only important source of 1O2 and 3CDOM* [1, 2]. CDOM origin plays a key role in sensitised processes: allochthonous CDOM derived from soil runoff and rich in fulvic and humic substances is usually more photoactive than autochthonous CDOM (produced by in-water biological processes and mainly consisting of protein-like material) or of CDOM derived from atmospheric deposition. An interesting gradual evolution of CDOM origin and photochemistry can be found in mountain lakes across the treeline, which afford a gradual transition of allochthonous- autochtonous - atmopheric CDOM when passing from trees to alpine meadows to exposed rocks [3]. Another important issue is the sites of reactive species photoproduction in CDOM. While there is evidence that smaller molecular weight fractions are more photoactive, some studies have reported considerable 1O2 reactivity in CDOM hydrophobic sites and inside particles [4]. We have recently addressed the problem and found that dissolved species in standard humic acids (hydrodynamic diameter pollutants to be assessed and modelled. For instance, it is possible to predict pollutant half-life times by knowing absorption spectrum, direct photolysis quantum yield and reaction rate constants with °OH, CO3

  6. Production of activated carbon by using pyrolysis process in an ammonia atmosphere

    Science.gov (United States)

    Indayaningsih, N.; Destyorini, F.; Purawiardi, R. I.; Insiyanda, D. R.; Widodo, H.

    2017-04-01

    Activated carbon is materials that have wide applications, including supercapacitor materials, absorbent in chemical industry, and absorbent material in the chemical industry. This study has carried out for the manufacturing of activated carbon from inexpensive materials through efficient processes. Carbon material was made from coconut fibers through pyrolysis process at temperature of 650, 700, 750 and 800°C. Aim of this study was to obtain carbon material that has a large surface area. Pyrolysis process is carried out in an inert atmosphere (N2 gas) at a temperature of 450°C for 30 minutes, followed by pyrolysis process in an ammonia atmosphere at 800°C for 2 hours. The pyrolysis results showed that the etching process in ammonia is occurred; as it obtained some greater surface area when compared with the pyrolisis process in an atmosphere by inert gas only. The resulted activated carbon also showed to have good properties in surface area and total pore volume.

  7. Modeling Aspects of Activated Sludge Processes Part l l: Mathematical Process Modeling and Biokinetics of Activated Sludge Processes

    Energy Technology Data Exchange (ETDEWEB)

    AbdElHaleem, H S [Cairo Univ.-CivlI Eng. Dept., Giza (Egypt); EI-Ahwany, A H [CairoUlmrsity- Faculty ofEngincering - Chemical Engineering Department, Giza (Egypt); Ibrahim, H I [Helwan University- Faculty of Engineering - Biomedical Engineering Department, Helwan (Egypt); Ibrahim, G [Menofia University- Faculty of Engineering Sbebin EI Kom- Basic Eng. Sc. Dept., Menofia (Egypt)

    2004-07-01

    Mathematical process modeling and biokinetics of activated sludge process were reviewed considering different types of models. It has been evaluated the task group models of ASMI. and 2, and 3 versioned by Henze et al considering the conditions of each model and the different processes of which every model consists. It is revealed that ASMI contains some defects avoided in ASM3. Relied on homogeneity, Models can be classified into homogenous models characterized by taking the activated sludge process as one phase. In this type of models, the internal mass transfer inside the floes was neglected.. Hence, the kinetic parameter produces can be considered inaccurate. The other type of models is the heterogeneous model This type considers the mass transfer operations in addition to the biochemical reaction processes; hence, the resulted kinetic parameters can be considered more accurate than that of homogenous type.

  8. Modeling Aspects of Activated Sludge Processes Part l l: Mathematical Process Modeling and Biokinetics of Activated Sludge Processes

    International Nuclear Information System (INIS)

    AbdElHaleem, H.S.; EI-Ahwany, A. H.; Ibrahim, H.I.; Ibrahim, G.

    2004-01-01

    Mathematical process modeling and biokinetics of activated sludge process were reviewed considering different types of models. It has been evaluated the task group models of ASMI. and 2, and 3 versioned by Henze et al considering the conditions of each model and the different processes of which every model consists. It is revealed that ASMI contains some defects avoided in ASM3. Relied on homogeneity, Models can be classified into homogenous models characterized by taking the activated sludge process as one phase. In this type of models, the internal mass transfer inside the floes was neglected.. Hence, the kinetic parameter produces can be considered inaccurate. The other type of models is the heterogeneous model This type considers the mass transfer operations in addition to the biochemical reaction processes; hence, the resulted kinetic parameters can be considered more accurate than that of homogenous type

  9. Characterization of surface processes on mineral surfaces in aqueous solutions. Annual report for fiscal year 1993

    International Nuclear Information System (INIS)

    Leckie, J.O.

    1993-11-01

    Performance assessments by Los Alamos National Laboratory for the DOE's Yucca Mountain Site Characterization Project (YMP) are being done investigating the environmental risk related to long-term disposal of hazardous wastes resulting from the use of radioactive materials that must subsequently be isolated from the environment. The YMP site, located in southwestern Nevada, is intended for the storage of high-level wastes generated by nuclear energy-related activities, including spent fuel and waste from reprocessed fuel rods. The work covered by this contract is necessary for producing a defensible model and dataset, and may be critical for evaluation of repository compliance. This work, performed by the Environmental Engineering and Science research group at Stanford University, will quantify the adsorption of uranyl on various minerals. The project's principle objective is to provide sorption coefficients for uranyl and other ions of interest to predict radionuclide movements form the repository to accessible environments. This adsorption data is essential for the unambiguous interpretation of field experiments and observations. In this report, details of the activity and progress made with respect to the study of uranyl adsorption on mineral surfaces is presented and discussed

  10. Microstructure and surface properties of lignocellulosic-based activated carbons

    Science.gov (United States)

    González-García, P.; Centeno, T. A.; Urones-Garrote, E.; Ávila-Brande, D.; Otero-Díaz, L. C.

    2013-01-01

    Low cost activated carbons have been produced via chemical activation, by using KOH at 700 °C, from the bamboo species Guadua Angustifolia and Bambusa Vulgaris Striata and the residues from shells of the fruits of Castanea Sativa and Juglans Regia as carbon precursors. The scanning electron microscopy micrographs show the conservation of the precursor shape in the case of the Guadua Angustifolia and Bambusa Vulgaris Striata activated carbons. Transmission electron microscopy analyses reveal that these materials consist of carbon platelet-like particles with variable length and thickness, formed by highly disordered graphene-like layers with sp2 content ≈ 95% and average mass density of 1.65 g/cm3 (25% below standard graphite). Textural parameters indicate a high porosity development with surface areas ranging from 850 to 1100 m2/g and average pore width centered in the supermicropores range (1.3-1.8 nm). The electrochemical performance of the activated carbons shows specific capacitance values at low current density (1 mA/cm2) as high as 161 F/g in the Juglans Regia activated carbon, as a result of its textural parameters and the presence of pseudocapacitance derived from surface oxygenated acidic groups (mainly quinones and ethers) identified in this activated carbon.

  11. Understanding the creation of & reducing surface microroughness during polishing & post-processing of glass optics

    Energy Technology Data Exchange (ETDEWEB)

    Suratwala, Tayyab [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-09-22

    In the follow study, we have developed a detailed understanding of the chemical and mechanical microscopic interactions that occur during polishing affecting the resulting surface microroughness of the workpiece. Through targeted experiments and modeling, the quantitative relationships of many important polishing parameters & characteristics affecting surface microroughness have been determined. These behaviors and phenomena have been described by a number of models including: (a) the Ensemble Hertzian Multi Gap (EHMG) model used to predict the removal rate and roughness at atomic force microscope (AFM) scale lengths as a function of various polishing parameters, (b) the Island Distribution Gap (IDG) model used to predict the roughness at larger scale lengths, (c) the Deraguin-Verwey-Landau-Overbeek (DLVO) 3-body electrostatic colloidal model used to predict the interaction of slurry particles at the interface and roughness behavior as a function of pH, and (d) a diffusion/chemical reaction rate model of the incorporation of impurities species into the polishing surface layer (called the Bielby layer). Based on this improved understanding, novel strategies to polish the workpiece have been developed simultaneously leading to both ultrasmooth surfaces and high material removal rates. Some of these strategies include: (a) use of narrow PSD slurries, (b) a novel diamond conditioning recipe of the lap to increase the active contact area between the workpiece and lap without destroying its surface figure, (c) proper control of pH for a given glass type to allow for a uniform distribution of slurry particles at the interface, and (d) increase in applied load just up to the transition between molecular to plastic removal regime for a single slurry particle. These techniques have been incorporated into a previously developed finishing process called Convergent Polishing leading to not just economical finishing process with improved surface figure control, but also

  12. Electron beam processed plasticized epoxy coatings for surface protection

    International Nuclear Information System (INIS)

    Ibrahim, Mervat S.; Mohamed, Heba A.; Kandile, Nadia G.; Said, Hossam M.; Mohamed, Issa M.

    2011-01-01

    Highlights: · Coating formulations with EA 70%, HD 20%, and castor oil 10% under 1 Mrad pass -1 irradiation dose showed the best adhesion and passed bending tests. · The prepared EP-SF-An adduct improve anti-corrosion properties of coatings without any significant effect on physical, mechanical and chemical properties of the cured film. The optimum amount of aniline adduct as corrosion inhibitor was found to be 0.4 g for 100 g of coating formulation. · The corrosion inhibition efficiency of the prepared adduct competed the commercial efficiency. - Abstract: Epoxy acrylate oligomer (EA) was plasticized by adding different plasticizers such as epoxidized soybean oil, glycerol and castor oil and cured by electron beam (EB). Different irradiation doses (1, 2.5 and 5 Mrad pass -1 ) were used in the curing process. The effect of both different irradiation doses and plasticizers on the end use performance properties of epoxy acrylate coating namely, pencil hardness, bending test, adhesion test, acid and alkali resistance test were studied. It was observed that incorporation of castor oil in epoxy acrylate diluted by 1,6-hexanediol diacrylate (HD) monomer with a ratio (EA 70%, HD 20%, castor oil 10%) under 1 Mrad pass -1 irradiation dose improved the physical, chemical and mechanical properties of cured films than the other plasticizer. Sunflower free fatty acid was epoxidized in situ under well established conditions. The epoxidized sunflower free fatty acids (ESFA) were subjected to react with aniline in sealed ampoules under inert atmosphere at 140 deg. C. The produced adducts were added at different concentrations to epoxy acrylate coatings under certain EB irradiation dose and then evaluated as corrosion inhibitors for carbon steel surfaces in terms of weight loss measurements and corrosion resistance tests. It was found that, addition of 0.4 g of aniline adduct to 100 g epoxy acrylate formula may give the best corrosion protection for carbon steel and compete the

  13. Electrochemical and morphological analyses on the titanium surface modified by shot blasting and anodic oxidation processes

    Energy Technology Data Exchange (ETDEWEB)

    Szesz, Eduardo M., E-mail: eszesz@neoortho.com.br [Neoortho Research Institute, Rua Ângelo Domingos Durigan, 607-Cascatinha, CEP 82025-100 Curitiba, PR (Brazil); Pereira, Bruno L., E-mail: brnl7@hotmail.com [Physics Department, Universidade Federal do Paraná, 81531-980 Curitiba, PR (Brazil); Kuromoto, Neide K., E-mail: kuromoto@fisica.ufpr.br [Physics Department, Universidade Federal do Paraná, 81531-980 Curitiba, PR (Brazil); Marino, Claudia E.B., E-mail: claudiamarino@yahoo.com [Mechanical Engineering Department, Universidade Federal do Paraná, 81531-980 Curitiba, PR (Brazil); Souza, Gelson B. de, E-mail: gelsonbs@uepg.br [Physics Department, Universidade Estadual de Ponta Grossa, 84051-510 Ponta Grossa, PR (Brazil); Soares, Paulo, E-mail: pa.soares@pucpr.br [Mechanical Engineering Department, Pontifícia Universidade Católica do Paraná, 80215-901 Curitiba, PR (Brazil)

    2013-01-01

    In recent years, many surface modification processes have been developed in order to induce the osseointegration on titanium surface and thus to improve the implants' biocompatibility. In this work, Ti surface has been modified by shot blasting followed by anodic oxidation process in order to associate the good surface characteristics of both processes to obtain a rough and porous surface able to promote the titanium surface bioactivity. Commercially pure titanium (grade 2) plates were used on the surface treatments that were as follows: Shot blasting (SB) performed using alumina (Al{sub 2}O{sub 3}) particles, and anodic oxidation (AO) using NaOH electrolyte. The morphology, structural changes and the open-circuit potentials (OCP) of the surfaces were analyzed. It can be observed that an increase on the roughness of the blasted surface and a rough and porous surface happens after the AO process. The anodic film produced is thin and followed the blasted surface topography. It can be observed that there are small pores with regular shape covering the entire surface. X-ray diffraction results showed the presence of the anatase and rutile phases on the blasted and anodized surface after heat treatment at 600 °C/1 h. Concerning electrochemical measurements, when the different samples were submitted to open-circuit conditions in a physiological electrolyte, the protective effect increases with the oxidation process due to the oxide layer. When the surface was blasted, the OCP was more negative when compared with the Ti surface without surface treatments. - Highlights: ► A combination of shot blasting and anodic oxidation surface treatments is proposed. ► Both processes produced an increase in roughness compared to the polished surface. ► The combination of processes produced a rough and porous surface. ► Open circuit results show that the protective effect increases with oxidation process. ► The combination of processes presents the better results in this

  14. Thin film surface processing by ultrashort laser pulses (USLP)

    NARCIS (Netherlands)

    Scorticati, D.; Skolski, J.Z.P.; Romer, G.R.B.E.; Huis in 't Veld, A.J.; Workum, M.J.; Theelen, M.J.; Zeman, M.

    2012-01-01

    In this work, we studied the feasibility of surface texturing of thin molybdenum layers on a borosilicate glass substrate with Ultra-Short Laser Pulses (USLP). Large areas of regular diffraction gratings were produced consisting of Laserinduced periodic surface structures (LIPSS). A short pulsed

  15. 23 CFR 450.208 - Coordination of planning process activities.

    Science.gov (United States)

    2010-04-01

    ... process. (h) The statewide transportation planning process should be consistent with the Strategic Highway... 23 Highways 1 2010-04-01 2010-04-01 false Coordination of planning process activities. 450.208... Coordination of planning process activities. (a) In carrying out the statewide transportation planning process...

  16. Effect of machining on the deformability of steel in surface-active medium at lower temperatures

    International Nuclear Information System (INIS)

    Gusti, E.Ya.; Babej, Yu.I.

    1977-01-01

    The effect of some machining methods of carbon steel, chromium steel, and chromium nickel steel, and that of low temperatures on the principle characteristics of formability during impact bending in air and a surface-active environment have been studied. The temperature decrease from the ambient to -80 deg is shown to reduce steel formability as evaluated by deflection (f) and to increase the forming force. The variation of these characteristics with lowering temperature, however, is greatly affected by machining process conditions. The FRHT (Friction-Hardening Treatment) on the white layer assures minimum ductility losses, and increases steel strength at low temperatures both in air and in the surface-active environment

  17. Study on the oxidation and reduction of tungsten surface for sub-50 nm patterning process

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Kyu; Nam, Seok Woo; Cho, Sung Il; Jhon, Myung S.; Min, Kyung Suk; Kim, Chan Kyu; Jung, Ho Bum; Yeom, Geun Young [Memory Division Semiconductor Business, Samsung Electronics, San No. 16 Banwol-Ri, Taean-Eup, Hwasung-City, Gyeonggi-Do 449-711, South Korea and Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of); Memory Division Semiconductor Business, Samsung Electronics, San No. 16 Banwol-Ri, Taean-Eup, Hwasung-City, Gyeonggi-Do 449-711 (Korea, Republic of); Department of Chemical Engineering and Data Storage Systems Center, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Department of Advanced Materials Science and Engineering, Sungkyunkwan University, Suwon, Gyeonggi-do 440-746 (Korea, Republic of)

    2012-11-15

    The oxidation characteristics of tungsten line pattern during the carbon-based mask-layer removal process using oxygen plasmas have been investigated for sub-50 nm patterning processes, in addition to the reduction characteristics of the WO{sub x} layer formed on the tungsten line surface using hydrogen plasmas. The surface oxidation of tungsten lines during the mask layer removal process could be minimized by using low-temperature (300 K) plasma processing for the removal of the carbon-based material. Using this technique, the thickness of WO{sub x} on the tungsten line could be decreased to 25% compared to results from high-temperature processing. The WO{sub x} layer could also be completely removed at a low temperature of 300 K using a hydrogen plasma by supplying bias power to the tungsten substrate to provide a activation energy for the reduction. When this oxidation and reduction technique was applied to actual 40-nm-CD device processing, the complete removal of WO{sub x} formed on the sidewall of tungsten line could be observed.

  18. Temperature effects on surface activity and application in oxidation ...

    Indian Academy of Sciences (India)

    Unknown

    Abstract. The γcmc values of CTAB–SDS decrease from 63⋅67 mN/m at 10°C to 36⋅38 mN/m at 90°C, slightly lower than those of either CTAB or SDS. Correspondingly, the CMC of CTAB–SDS decreases almost by half. The increase of surface activity of CTAB–SDS can be attributed to the relatively weak electrostatic ...

  19. A critical assessment of theoretical methods for finding reaction pathways and transition states of surface processes

    International Nuclear Information System (INIS)

    Klimes, JirI; Michaelides, Angelos; Bowler, David R

    2010-01-01

    The performance of a variety of techniques for locating transition states on potential energy surfaces is evaluated within the density functional theory framework. Diffusion of a water molecule across NaCl(001) and HCl bond breaking on the same surface are treated as general test cases; the former is an example of a low barrier diffusion process and the latter an example of a relatively high barrier covalent bond rupture event. The methods considered include the nudged elastic band (NEB), Dewar, Healy and Stewart (DHS), dimer, constrained optimization (CO), activation-relaxation technique (ART) and one-side growing string (OGS) as well as novel combinations of the DHS with growing string (DHS + GS) and DHS plus climbing image (CI-DHS). A key conclusion to come from this study is that the NEB method is relatively fast, especially when just a single (climbing) image is used. Indeed, using more images represents an unnecessary computational burden for our set of processes. The dimer method exhibits variable performance; being poor for the water diffusion processes, which have small activation energies, but much more efficient for the HCl bond breaking process which has a higher barrier. When only a poor initial guess of the transition state geometry is available, the CI-DHS scheme is one of the most efficient techniques considered. And as a means to quickly establish an approximate minimum energy pathway the DHS + GS scheme offers some potential.

  20. Degassing Processes at Persistently Active Explosive Volcanoes

    Science.gov (United States)

    Smekens, Jean-Francois

    Among volcanic gases, sulfur dioxide (SO2) is by far the most commonly measured. More than a monitoring proxy for volcanic degassing, SO 2 has the potential to alter climate patterns. Persistently active explosive volcanoes are characterized by short explosive bursts, which often occur at periodic intervals numerous times per day, spanning years to decades. SO 2 emissions at those volcanoes are poorly constrained, in large part because the current satellite monitoring techniques are unable to detect or quantify plumes of low concentration in the troposphere. Eruption plumes also often show high concentrations of ash and/or aerosols, which further inhibit the detection methods. In this work I focus on quantifying volcanic gas emissions at persistently active explosive volcanoes and their variations over short timescales (minutes to hours), in order to document their contribution to natural SO2 flux as well as investigate the physical processes that control their behavior. In order to make these measurements, I first develop and assemble a UV ground-based instrument, and validate it against an independently measured source of SO2 at a coal-burning power plant in Arizona. I establish a measurement protocol and demonstrate that the instrument measures SO 2 fluxes with Indonesia), a volcano that has been producing cycles of repeated explosions with periods of minutes to hours for the past several decades. Semeru produces an average of 21-71 tons of SO2 per day, amounting to a yearly output of 8-26 Mt. Using the Semeru data, along with a 1-D transient numerical model of magma ascent, I test the validity of a model in which a viscous plug at the top of the conduit produces cycles of eruption and gas release. I find that it can be a valid hypothesis to explain the observed patterns of degassing at Semeru. Periodic behavior in such a system occurs for a very narrow range of conditions, for which the mass balance between magma flux and open-system gas escape repeatedly

  1. Effect of sulfation on the surface activity of CaO for N2O decomposition

    International Nuclear Information System (INIS)

    Wu, Lingnan; Hu, Xiaoying; Qin, Wu; Dong, Changqing; Yang, Yongping

    2015-01-01

    Graphical abstract: - Highlights: • Sulfation of CaO (1 0 0) surface greatly deactivates its surface activity for N 2 O decomposition. • An increase of sulfation degree leads to a decrease of CaO surface activity for N 2 O decomposition. • Sulfation from CaSO 3 into CaSO 4 is the crucial step for deactivating the surface activity for N 2 O decomposition. • The electronic interaction CaO (1 0 0)/CaSO 4 (0 0 1) interface is limited to the bottom layer of CaSO 4 (0 0 1) and the top layer of CaO (1 0 0). • CaSO 4 (0 0 1) and (0 1 0) surfaces show negligible catalytic ability for N 2 O decomposition. - Abstract: Limestone addition to circulating fluidized bed boilers for sulfur removal affects nitrous oxide (N 2 O) emission at the same time, but mechanism of how sulfation process influences the surface activity of CaO for N 2 O decomposition remains unclear. In this paper, we investigated the effect of sulfation on the surface properties and catalytic activity of CaO for N 2 O decomposition using density functional theory calculations. Sulfation of CaO (1 0 0) surface by the adsorption of a single gaseous SO 2 or SO 3 molecule forms stable local CaSO 3 or CaSO 4 on the CaO (1 0 0) surface with strong hybridization between the S atom of SO x and the surface O anion. The formed local CaSO 3 increases the barrier energy of N 2 O decomposition from 0.989 eV (on the CaO (1 0 0) surface) to 1.340 eV, and further sulfation into local CaSO 4 remarkably increases the barrier energy to 2.967 eV. Sulfation from CaSO 3 into CaSO 4 is therefore the crucial step for deactivating the surface activity for N 2 O decomposition. Completely sulfated CaSO 4 (0 0 1) and (0 1 0) surfaces further validate the negligible catalytic ability of CaSO 4 for N 2 O decomposition.

  2. Preparation of self-cleaning surfaces with a dual functionality of superhydrophobicity and photocatalytic activity

    Science.gov (United States)

    Park, Eun Ji; Yoon, Hye Soo; Kim, Dae Han; Kim, Yong Ho; Kim, Young Dok

    2014-11-01

    Thin film of polydimethylsiloxane (PDMS) was deposited on SiO2 nanoparticles by chemical vapor deposition, and SiO2 became completely hydrophobic after PDMS coating. Mixtures of TiO2 and PDMS-coated SiO2 nanoparticles with various relative ratios were prepared, and distributed on glass surfaces, and water contact angles and photocatalytic activities of these surfaces were studied. Samples consisting of TiO2 and PDMS-coated SiO2 with a ratio of 7:3 showed a highly stable superhydrophobicity under UV irradiation with a water contact angle of 165° and UV-driven photocatalytic activity for decomposition of methylene blue and phenol in aqueous solution. Our process can be exploited for fabricating self-cleaning surfaces with dual functionality of superhydrophobicity and photocatalytic activity at the same time.

  3. The porous surface model, a novel experimental system for online quantitative observation of microbial processes under unsaturated conditions

    DEFF Research Database (Denmark)

    Dechesne, Arnaud; Or, D.; Gulez, Gamze

    2008-01-01

    Water is arguably the most important constituent of microbial microhabitats due to its control of physical and physiological processes critical to microbial activity. In natural environments, bacteria often live on unsaturated surfaces, in thin (micrometric) liquid films. Nevertheless, no experim....... The PSM constitutes a tool uniquely adapted to study the influence of liquid film geometry on microbial processes. It should therefore contribute to uncovering mechanisms of microbial adaptation to unsaturated environments.......Water is arguably the most important constituent of microbial microhabitats due to its control of physical and physiological processes critical to microbial activity. In natural environments, bacteria often live on unsaturated surfaces, in thin (micrometric) liquid films. Nevertheless......, no experimental systems are available that allow real-time observation of bacterial processes in liquid films of controlled thickness. We propose a novel, inexpensive, easily operated experimental platform, termed the porous surface model (PSM) that enables quantitative real-time microscopic observations...

  4. Improving the work function of the niobium surface of SRF cavities by plasma processing

    Science.gov (United States)

    Tyagi, P. V.; Doleans, M.; Hannah, B.; Afanador, R.; McMahan, C.; Stewart, S.; Mammosser, J.; Howell, M.; Saunders, J.; Degraff, B.; Kim, S.-H.

    2016-04-01

    An in situ plasma processing technique using chemically reactive oxygen plasma to remove hydrocarbons from superconducting radio frequency cavity surfaces at room temperature has been developed at the spallation neutron source, at Oak Ridge National Laboratory. To understand better the interaction between the plasma and niobium surface, surface studies on small samples were performed. In this article, we report the results from those surface studies. The results show that plasma processing removes hydrocarbons from top surface and improves the surface work function by 0.5-1.0 eV. Improving the work function of RF surface of cavities can help to improve their operational performance.

  5. Manufacture of functional surfaces through combined application of tool manufacturing processes and Robot Assisted Polishing

    DEFF Research Database (Denmark)

    Eriksen, Rasmus Solmer; Arentoft, Mogens; Grønbæk, J.

    2012-01-01

    The tool surface topography is often a key parameter in the tribological performance of modern metal forming tools. A new generation of multifunctional surfaces is achieved by combination of conventional tool manufacturing processes with a novel Robot Assisted Polishing process. This novel surface...

  6. High surface area microporous activated carbons prepared from Fox nut (Euryale ferox) shell by zinc chloride activation

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Arvind; Mohan Jena, Hara, E-mail: hmjena@nitrkl.ac.in

    2015-11-30

    Graphical abstract: - Highlights: • Activated carbons have been prepared from Fox nutshell with chemical activation using ZnCl{sub 2}. • The thermal behavior of the raw material and impregnated raw material has been carried out by thermogravimetric analysis. • The characterizations of the prepared activated carbons have been determined by nitrogen adsorption–desorption isotherms, FTIR, XRD, and FESEM. • The BET surface area and total pore volume of prepared activated carbon has been obtained as 2869 m{sup 2}/g, 2124 m{sup 2}/g, and 1.96 cm{sup 3}/g, respectively. • The microporous surface area, micropore volume, and microporosity percentage of prepared activated carbon has been obtained as 2124 m{sup 2}/g, 1.68 cm{sup 3}/g, and 85.71%, respectively. - Abstract: High surface area microporous activated carbon has been prepared from Fox nutshell (Euryale ferox) by chemical activation with ZnCl{sub 2} as an activator. The process has been conducted at different impregnation (ZnCl{sub 2}/Fox nutshell) ratios (1–2.5) and carbonization temperatures (500–700 °C). The thermal decomposition behavior of Fox nutshell and impregnated Fox nutshell has been carried out by thermogravimetric analysis. The pore properties including the BET surface area, micropore surface area, micropore volume, and pore size distribution of the activated carbons have been determined by nitrogen adsorption–desorption isotherms at −196 °C using the BET, t-plot method, DR, and BJH methods. The BET surface area, the microporous surface area, total pore volume, and micropore volume have been obtained as 2869 m{sup 2}/g, 2124 m{sup 2}/g, 1.96 cm{sup 3}/g, and 1.68 cm{sup 3}/g, respectively, and the microporosity percentage of the prepared activated carbon is 85.71%. The prepared activated carbons have been also characterized with instrumental methods such as Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and field emission scanning electron microscopy (FESEM).

  7. PROCESSES PROCEEDING ON CONCRETE COATING SURFACES IN CASE OF THEIR CHEMICAL PROTECTION AGAINST WINTER SLIPPERINESS

    Directory of Open Access Journals (Sweden)

    M. K. Pshembaev

    2016-01-01

    Full Text Available Concrete coatings of road traffic highways along with operational loadings caused by flow of traffic are subjected to weather and climate impacts. These are the following impacts: changes in temperature and air humidity, solar radiation,surface wind speed which is participating in formation of active heat-and-mass transfer in a surface layer of the concrete coating. One of the most complicated and important periods in the road traffic highway operation is so called transitional nature period (from Summer to Autumn and from Winter to Spring. These periods are accompanied by intensive rain and snow fall and possible formation of ice loading on the surface of cement and concrete coatings. These impacts significantly deteriorate friction properties of road pavement (friction factor φ is decreased up to 0.4 and less that can be a prerequisite to creation of various accident situations due to sharp increase in braking distance. For example, while having dry pavement the friction factor φ is equal to 0.80–0.85, and during icy condition of the road the factor φ constitutes 0.08–0.15 that consequently entails an increase in braking distance from 7.5 up to 20.0 m and more. It is quite possible that ice layer appears on the surface of concrete coatings when road traffic highways are used in winter season. Various methods are applicable to remove ice from the surface they can include also ice-melting chemicals and sodium chloride NaCl in particular. The chemical decreases freezing temperature of the formed brine and causes ice melting at negative temperature. Processes of NaCl dissolution and ice melting have an endothermic character, in other words these processes are accompanied by heat ingress and due to it temperature is sharply decreasing in the surface layer of the concrete coating which is under the melting ice and in this case phenomenon of thermal shock is observed.

  8. Influence of chemical agents on the surface area and porosity of active carbon hollow fibers

    Directory of Open Access Journals (Sweden)

    LJILJANA M. KLJAJEVIĆ

    2011-09-01

    Full Text Available Active carbon hollow fibers were prepared from regenerated polysulfone hollow fibers by chemical activation using: disodium hydrogen phosphate 2-hydrate, disodium tetraborate 10-hydrate, hydrogen peroxide, and diammonium hydrogen phosphate. After chemical activation fibers were carbonized in an inert atmosphere. The specific surface area and porosity of obtained carbons were studied by nitrogen adsorption–desorption isotherms at 77 K, while the structures were examined with scanning electron microscopy and X-ray diffraction. The activation process increases these adsorption properties of fibers being more pronounced for active carbon fibers obtained with disodium tetraborate 10-hydrate and hydrogen peroxide as activator. The obtained active hollow carbons are microporous with different pore size distribution. Chemical activation with phosphates produces active carbon material with small surface area but with both mesopores and micropores. X-ray diffraction shows that besides turbostratic structure typical for carbon materials, there are some peaks which indicate some intermediate reaction products when sodium salts were used as activating agent. Based on data from the electrochemical measurements the activity and porosity of the active fibers depend strongly on the oxidizing agent applied.

  9. Effects of titanium surface topography on morphology and in vitro activity of human gingival fibroblasts.

    Science.gov (United States)

    Ramaglia, L; Capece, G; Di Spigna, G; Bruno, M P; Buonocore, N; Postiglione, L

    2013-01-01

    The aim of the present study was to evaluate in vitro the biological behavior of human gingival fibroblasts cultured on two different titanium surfaces. Titanium test disks were prepared with a machined, relatively smooth (S) surface or a rough surface (O) obtained by a double acid etching procedure. Primary cultures of human gingival fibroblasts were plated on the experimental titanium disks and cultured up to 14 days. Titanium disk surfaces were analysed by scanning electron microscopy (SEM). Cell proliferation and a quantitative analysis by ELISA in situ of ECM components as CoI, FN and TN were performed. Results have shown different effects of titanium surface microtopography on cell expression and differentiation. At 96 hours of culture on experimental surfaces human gingival fibroblasts displayed a favourable cell attachment and proliferation on both surfaces although showing some differences. Both the relatively smooth and the etched surfaces interacted actively with in vitro cultures of human gingival fibroblasts, promoting cell proliferation and differentiation. Results suggested that the microtopography of a double acid-etched rough surface may induce a greater Co I and FN production, thus conditioning in vivo the biological behaviour of human gingival fibroblasts during the process of peri-implant soft tissue healing.

  10. Coronal Structures as Tracers of Sub-Surface Processes

    Indian Academy of Sciences (India)

    tribpo

    dramatic differences in appearance and physical processes, all these structures share a common ... mena that indicate a close relationship between coronal and sub-photo- spheric processes. .... 8) maintaining the same chirality. Large scale ...

  11. A description of the BNL active surface analysis facility

    International Nuclear Information System (INIS)

    Tyler, J.W.

    1989-11-01

    Berkeley Nuclear Laboratories has a responsibility for the assessment of radioactive specimens arising both from post irradiation examination of power reactor components and structures and experimental programmes concerned with fission and activation product transport. Existing analytical facilities have been extended with the commissioning of an active surface analysis instrument (XSAM 800pci, Kratos Analytical). Surface analysis involves the characterisation of the outer few atomic layers of a solid surface/interface whose chemical composition and electronic structure will probably be different from the bulk. The new instrument consists three interconnected chambers positioned in series; comprising of a high vacuum sample introduction chamber, an ultra-high vacuum sample treatment/fracture chamber and an ultra-high vacuum sample analysis chamber. The sample analysis chamber contains the electron, X-ray and ion-guns and the electron and ion detectors necessary for performing X-ray photoelectron spectroscopy, scanning Auger microscopy and secondary-ion mass spectroscopy. The chamber also contains a high stability manipulator to enable sub-micron imaging of specimens to be achieved and provide sample heating and cooling between - 180 and 600 0 C. (author)

  12. Lunar rock surfaces as detectors of solar processes

    International Nuclear Information System (INIS)

    Hartung, J.B.; Hunter College, New York, NY)

    1980-01-01

    Lunar rock surfaces exposed at or just below the lunar surface are considered as detectors of the solar wind, solar flares and solar-derived magnetic fields through their interactions with galactic cosmic rays. The degradation of the solar detector capabilities of lunar surface rocks by meteoroid impact erosion, accreta deposition, loose dust, and sputtering, amorphous layer formation and accelerated diffusion due to solar particles and illumination is discussed, and it is noted that the complex interactions of factors affecting the outer micron of exposed surface material has so far prevented the development of a satisfactory model for a particle detector on the submicron scale. Methods for the determination of surface exposure ages based on the accumulation of light solar wind noble gases, Fe and Mg, impact craters, solar flare tracks, and cosmogenic Kr isotopes are examined, and the systematic variations in the ages determined by the various clocks are discussed. It is concluded that a means of obtaining satisfactory quantitative rate or flux data has not yet been established

  13. Surface processing with ionized cluster beams: computer simulation

    International Nuclear Information System (INIS)

    Insepov, Z.; Yamada, I.

    1999-01-01

    Molecular Dynamics (MD) and Monte Carlo (MC) models of energetic gas cluster irradiation of a solid surface have been developed to investigate the phenomena of crater formation, sputtering, surface treatment, and the material hardness evaluation by irradiation with cluster ions. Theoretical estimation of crater dimensions formed with Ar gas cluster ion irradiation of different substrates, based on hydrodynamics and MD simulation, are presented. The atomic scale shock waves arising from cluster impact were obtained by calculating the pressure, temperature and mass-velocity of the target atoms. The crater depth is given as a unique 1/3 dependence on the cluster energy and on the cold material Brinell hardness number (BHN). A new 'true material hardness' scale which can be very useful for example for thin film coatings deposited on a soft substrate, is defined. This finding could be used as a new technique for measuring of a material hardness. Evolution of surface morphology under cluster ion irradiation was described by the surface relaxation equation which contains a term of crater formation at cluster impact. The formation of ripples on a surface irradiated with oblique cluster ion beams was predicted. MD and MC models of Decaborane ion (B 10 H 14 ) implantation into Si and the following rapid thermal annealing (RTA) have been developed

  14. Effects of Activated Carbon Surface Property on Structure and Activity of Ru/AC Catalysts

    Science.gov (United States)

    Xu, S. K.; Li, L. M.; Guo, N. N.

    2018-05-01

    The activated carbon (AC) was modified by supercritical (SC) methanol, HNO3 oxidation, or HNO3 oxidation plus SC methanol, respectively. Then, the original and the modified AC were used as supports for Ru/AC catalysts prepared via the impregnation method. The results showed that the SC methanol modification decreased the content of surface acidic groups of AC. While HNO3 oxidation displayed the opposite behavior. Furthermore, the dispersion of ruthenium and the activity of catalysts were highly dependent on the content of surface acidic groups, and the SC methanol modified sample exhibited the highest activity for hydrogenation of glucose.

  15. A decision-making process on cleanup of contaminated surface soil

    International Nuclear Information System (INIS)

    Yasuda, Hiroshi

    1996-01-01

    This study presents principles for determining derived intervention levels (DILs) for surface soil cleanup. The people concerned were divided into major three groups: residents, responsible parties, and cleanup workers; it was considered that each group has different interests. The DILs for soil cleanup were determined from the viewpoints of these three groups: safety of residence, advantages of the countermeasures, and safety of cleanup activities, respectively. An example process for determination of the DILs in accordance with the principles was also presented for a site contaminated by 137 Cs. This decision-making frame is expected to be applicable to other contaminants. (author)

  16. comparison of sorption capacity and surface area of activated

    African Journals Online (AJOL)

    Preferred Customer

    Activated carbons were prepared from fruit pericarp and seed coat of Jatropha curcas ... The process of adsorption is widely used as an effective physical method of ... The sample was then purified with 0.5–1.0 M HCl solution, rinsed with water.

  17. Upper Meter Processes: Short Wind Waves, Surface Flow, and Micro-Turbulence

    National Research Council Canada - National Science Library

    Jaehne, Bernd

    2000-01-01

    The primary goal of this project was to advance the knowledge of small-scale air-sea interaction processes at the ocean surface, focussing on the dynamics of short waves, the surface flow field and the micro-turbulence...

  18. Predesigned surface patterns and topological defects control the active matter.

    Science.gov (United States)

    Turiv, Taras; Peng, Chenhui; Guo, Yubing; Wei, Qi-Huo; Lavrentovich, Oleg

    Active matter exhibits remarkable patterns of never-ending dynamics with giant fluctuations of concentration, varying order, nucleating and annihilating topological defects. These patterns can be seen in active systems of both biological and artificial origin. A fundamental question is whether and how one can control this chaotic out-of-equilibrium behavior. We demonstrate a robust control of local concentration, trajectories of active self-propelled units and the net flows of active bacteria Bacillus Substilis by imposing pre-designed surface patterns of orientational order in a water-based lyotropic chromonic liquid crystal. The patterns force the bacteria to gather into dynamic swarms with spatially modulated concentration and well-defined polarity of motion. Topological defects produce net motion of bacteria with a unidirectional circulation, while pairs of defects induce a pumping action. The qualitative features of the dynamics can be explained by interplay of curvature and activity, in particular, by ability of mixed splay-bend curvatures to generate threshold-less active flows. The demonstrated level of control opens opportunities in engineering materials and devices that mimic rich functionality of living systems. This work was supported by NSF Grants DMR-1507637, DMS-1434185, CMMI-1436565, by the Petroleum Research Grant PRF# 56046-ND7 administered by the American Chemical Society.

  19. Shewanella putrefaciens Adhesion and Biofilm Formation on Food Processing Surfaces

    Science.gov (United States)

    Bagge, Dorthe; Hjelm, Mette; Johansen, Charlotte; Huber, Ingrid; Gram, Lone

    2001-01-01

    Laboratory model systems were developed for studying Shewanella putrefaciens adhesion and biofilm formation under batch and flow conditions. S. putrefaciens plays a major role in food spoilage and may cause microbially induced corrosion on steel surfaces. S. putrefaciens bacteria suspended in buffer adhered readily to stainless steel surfaces. Maximum numbers of adherent bacteria per square centimeter were reached in 8 h at 25°C and reflected the cell density in suspension. Numbers of adhering bacteria from a suspension containing 108 CFU/ml were much lower in a laminar flow system (modified Robbins device) (reaching 102 CFU/cm2) than in a batch system (reaching 107 CFU/cm2), and maximum numbers were reached after 24 h. When nutrients were supplied, S. putrefaciens grew in biofilms with layers of bacteria. The rate of biofilm formation and the thickness of the film were not dependent on the availability of carbohydrate (lactate or glucose) or on iron starvation. The number of S. putrefaciens bacteria on the surface was partly influenced by the presence of other bacteria (Pseudomonas fluorescens) which reduced the numbers of S. putrefaciens bacteria in the biofilm. Numbers of bacteria on the surface must be quantified to evaluate the influence of environmental factors on adhesion and biofilm formation. We used a combination of fluorescence microscopy (4′,6′-diamidino-2-phenylindole staining and in situ hybridization, for mixed-culture studies), ultrasonic removal of bacteria from surfaces, and indirect conductometry and found this combination sufficient to quantify bacteria on surfaces. PMID:11319118

  20. Self-activated, self-limiting reactions on Si surfaces

    DEFF Research Database (Denmark)

    Morgen, Per; Hvam, Jeanette; Bahari, Ali

    The direct thermally activated reactions of oxygen and ammonia with Si surfaces in furnaces have been used for a very long time in the semiconductor industry for the growth of thick oxides and nitride layers respectively. The oxidation mechanism was described in the Deal-Grove model as a diffusion...... mechanism for the direct growth of ultrathin films (0-3 nm) of oxides and nitrides under ultrahigh vacuum conditions. Neutral oxygen and a microwave excited nitrogen plasma interact directly with Si surfaces kept at different temperatures during the reaction. The gas pressures are around 10-6 Torr...... energy of an oxide system, which happened for an ordered structure, at a thickness of 0.7-0.8 nm. Thus this thin oxide structure has definite crystalline features. We have closely monitored the reaction kinetics with normal x-ray induced photoelectron spectroscopies, and also the structure, composition...

  1. Effect of finishing process on the surface quality of Co-Cr-Mo dental alloys

    Directory of Open Access Journals (Sweden)

    Dorota Klimecka -Tatar

    2016-09-01

    Full Text Available Preparatory procedures for the material have a significant influence on the surface stereometry of the material. This study investigated the effect of the electropolishing process on the surface quality of metallic prosthetic constructions based on Co-Cr-Mo alloys. It has been found that the process of electropolishing prevents to excessive development of the surface of a material and consequently improves surface quality.

  2. Bacterial desorption from food container and food processing surfaces.

    Science.gov (United States)

    McEldowney, S; Fletcher, M

    1988-03-01

    The desorption ofStaphylococcus aureus, Acinetobacter calcoaceticus, and a coryneform from the surfaces of materials used for manufacturing food containers (glass, tin plate, and polypropylene) or postprocess canning factory conveyor belts (stainless steel and nylon) was investigated. The effect of time, pH, temperature, and adsorbed organic layers on desorption was studied.S. aureus did not detach from the substrata at any pH investigated (between pH 5 and 9).A. calcoaceticus and the coryneform in some cases detached, depending upon pH and substratum composition. The degree of bacterial detachment from the substrata was not related to bacterial respiration at experimental pH values. Bacterial desorption was not affected by temperature (4-30°C) nor by an adsorbed layer of peptone and yeast extract on the substrata. The results indicate that bacterial desorption, hence bacterial removal during cleaning or their transfer via liquids flowing over colonized surfaces, is likely to vary with the surface composition and the bacterial species colonizing the surfaces.

  3. Nano surface generation of grinding process using carbon nano tubes

    Indian Academy of Sciences (India)

    Nano surface finish has become an important parameter in the semiconductor, optical, electrical and mechanical industries. The materials used in these industries are classified as difficult to machine materials such as ceramics, glasses and silicon wafers. Machining of these materials up to nano accuracy is a great ...

  4. Influence of surface effects on subsecond processes in liquid metals

    International Nuclear Information System (INIS)

    Tkachenko, S.I.; Vorob'ev, V.S.; Khishchenko, K.V.

    2001-01-01

    Full Text: We discuss a problem of experimental-data interpretation during subsecond measurements of thermophysical properties of matter at high temperatures and pressures. Peculiarity of these measurements is optical opaqueness of matter under interesting conditions (T∼1 eV, ρ∼10 4 kg m -3 ), so only at assuming of bulk specimen uniformity one can obtain a temperature dependencies of the specific properties of matter. Changing circuit current and changing sample geometry we can avoid a development of hydromagnetic instability and decrease a nonuniform heating due to skin effect. As temperature of wire surface reaches the boiling temperature under normal pressure so part of internal energy is lost because of evaporation and surface radiation at high temperature. So one can register a surface temperature and ascribe it to the whole sample bulk. Computer simulation of wire explosion taking into account surface radiation losses was carried out. Typical phase tracks for matter were obtained in both case as in consideration of radiation losses as without it. Comparison of the results with data concerning to isobaric-expansion experiments and semi-empirical multi-phase equation of state were carried out. It was proposed uniformity criterion for investigation of thermophysical properties of liquid metal by subsecond wire explosion. (author)

  5. Surface modification, characterization and adsorptive properties of a coconut activated carbon

    Energy Technology Data Exchange (ETDEWEB)

    Lu Xincheng [Institute of Chemical Industry of Forest Products, CAF, National Engineering Lab. for Biomass Chemical Utilization, Key and Open Lab. of Forest Chemical Engineering, SFA, Key Lab. of Biomass Energy and Material, Jiangsu Province, Suojin wucun 16, Nanjing 210042 (China); Jiang Jianchun, E-mail: lhs_ac2011@yahoo.cn [Institute of Chemical Industry of Forest Products, CAF, National Engineering Lab. for Biomass Chemical Utilization, Key and Open Lab. of Forest Chemical Engineering, SFA, Key Lab. of Biomass Energy and Material, Jiangsu Province, Suojin wucun 16, Nanjing 210042 (China); Sun Kang; Xie Xinping; Hu Yiming [Institute of Chemical Industry of Forest Products, CAF, National Engineering Lab. for Biomass Chemical Utilization, Key and Open Lab. of Forest Chemical Engineering, SFA, Key Lab. of Biomass Energy and Material, Jiangsu Province, Suojin wucun 16, Nanjing 210042 (China)

    2012-08-01

    A coconut activated carbon was modified using chemical methods. Different concentration of nitric acid oxidation of the conventional sample produced samples with weakly acidic functional groups. The oxidized samples were characterized by scanning electron micrograph, nitrogen absorption-desorption, Fourier transform infra red spectroscopy, Bothem method, pH titration, adsorption capacity of sodium and formaldehyde, and the adsorption mechanism of activated carbons was investigated. The results showed that BET surface area and pore volume of activated carbons were decreased after oxidization process, while acidic functional groups were increased. The surface morphology of oxidized carbons looked clean and eroded which was caused by oxidization of nitric acid. The oxidized carbons showed high adsorption capacity of sodium and formaldehyde, and chemical properties of activated carbon played an important role in adsorption of metal ions and organic pollutants.

  6. Elementary processes in plasma-surface interactions with emphasis on ions

    International Nuclear Information System (INIS)

    Zalm, P.C.

    1985-01-01

    Elementary processes occurring at solid surfaces immersed in low pressure plasmas are reviewed. In particular mechanisms leading to anisotropic or directional etching are discussed. The crucial role of ion bombardment is emphasized. First a brief summary of the interaction of (excited) neutrals, ions and electrons with targets is given. Next various aspects of sputter-etching with noble gas and reactive ions are surveyed. Finally it will be argued that synergistic effects, invoked by ion bombardment of a surface under simultaneous exposure to a reactive gas flux, are foremost important in explaining anisotropic plasma etching. It is shown that the role of the ions is not merely to stimulate the chemical reaction path but rather that the active gas flow chemically enhances the sputtering. (author)

  7. Supercritical processing as a route to high internal surface areas and permanent microporosity in metal-organic framework materials.

    Science.gov (United States)

    Nelson, Andrew P; Farha, Omar K; Mulfort, Karen L; Hupp, Joseph T

    2009-01-21

    Careful processing of four representative metal-organic framework (MOF) materials with liquid and supercritical carbon dioxide (ScD) leads to substantial, or in some cases spectacular (up to 1200%), increases in gas-accessible surface area. Maximization of surface area is key to the optimization of MOFs for many potential applications. Preliminary evidence points to inhibition of mesopore collapse, and therefore micropore accessibility, as the basis for the extraordinarily efficacious outcome of ScD-based activation.

  8. Earthquake rupture process recreated from a natural fault surface

    Science.gov (United States)

    Parsons, Thomas E.; Minasian, Diane L.

    2015-01-01

    What exactly happens on the rupture surface as an earthquake nucleates, spreads, and stops? We cannot observe this directly, and models depend on assumptions about physical conditions and geometry at depth. We thus measure a natural fault surface and use its 3D coordinates to construct a replica at 0.1 m resolution to obviate geometry uncertainty. We can recreate stick-slip behavior on the resulting finite element model that depends solely on observed fault geometry. We clamp the fault together and apply steady state tectonic stress until seismic slip initiates and terminates. Our recreated M~1 earthquake initiates at contact points where there are steep surface gradients because infinitesimal lateral displacements reduce clamping stress most efficiently there. Unclamping enables accelerating slip to spread across the surface, but the fault soon jams up because its uneven, anisotropic shape begins to juxtapose new high-relief sticking points. These contacts would ultimately need to be sheared off or strongly deformed before another similar earthquake could occur. Our model shows that an important role is played by fault-wall geometry, though we do not include effects of varying fluid pressure or exotic rheologies on the fault surfaces. We extrapolate our results to large fault systems using observed self-similarity properties, and suggest that larger ruptures might begin and end in a similar way, though the scale of geometrical variation in fault shape that can arrest a rupture necessarily scales with magnitude. In other words, fault segmentation may be a magnitude dependent phenomenon and could vary with each subsequent rupture.

  9. Improving the work function of the niobium surface of SRF cavities by plasma processing

    International Nuclear Information System (INIS)

    Tyagi, P.V.; Doleans, M.; Hannah, B.; Afanador, R.; McMahan, C.; Stewart, S.; Mammosser, J.; Howell, M.; Saunders, J.; Degraff, B.; Kim, S.-H.

    2016-01-01

    Highlights: • An in situ plasma processing for SNS SRF cavities has been developed to remove hydrocarbons from cavity surface. • Reactive oxygen plasma is very effective to remove hydrocarbons from niobium top surface. • Reactive oxygen plasma processing increases the work function of niobium surface in the range of 0.5–1.0 eV. • It was observed that hydrocarbons can migrate at plasma cleaned top surface from near surface regions when waiting in vacuum at room temperature. • Multiple cycles of plasma processing with waiting periods in between was found beneficial to mitigate such hydrocarbons migration at plasma cleaned surface. - Abstract: An in situ plasma processing technique using chemically reactive oxygen plasma to remove hydrocarbons from superconducting radio frequency cavity surfaces at room temperature has been developed at the spallation neutron source, at Oak Ridge National Laboratory. To understand better the interaction between the plasma and niobium surface, surface studies on small samples were performed. In this article, we report the results from those surface studies. The results show that plasma processing removes hydrocarbons from top surface and improves the surface work function by 0.5–1.0 eV. Improving the work function of RF surface of cavities can help to improve their operational performance.

  10. Surface enhancement of cold work tool steels by friction stir processing with a pinless tool

    Science.gov (United States)

    Costa, M. I.; Verdera, D.; Vieira, M. T.; Rodrigues, D. M.

    2014-03-01

    The microstructure and mechanical properties of enhanced tool steel (AISI D2) surfaces produced using a friction stir welding (FSW) related procedure, called friction stir processing (FSP), are analysed in this work. The surface of the tool steel samples was processed using a WC-Co pinless tool and varying processing conditions. Microstructural analysis revealed that meanwhile the original substrate structure consisted of a heterogeneous distribution of coarse carbides in a ferritic matrix, the transformed surfaces consisted of very small carbides, homogenously distributed in a ferrite- bainite- martensite matrix. The morphology of the surfaces, as well as its mechanical properties, evaluated by hardness and tensile testing, were found to vary with increasing tool rotation speed. Surface hardness was drastically increased, relative to the initial hardness of bulk steel. This was attributed to ferrite and carbide refinement, as well as to martensite formation during solid state processing. At the highest rotation rates, tool sliding during processing deeply compromised the characteristics of the processed surfaces.

  11. Perspective of surface active agents in baking industry: an overview.

    Science.gov (United States)

    Ahmad, Asif; Arshad, Nazish; Ahmed, Zaheer; Bhatti, Muhammad Shahbaz; Zahoor, Tahir; Anjum, Nomana; Ahmad, Hajra; Afreen, Asma

    2014-01-01

    Different researchers have previously used surfactants for improving bread qualities and revealed that these compounds result in improving the quality of dough and bread by influencing dough strength, tolerance, uniform crumb cell size, and improve slicing characteristics and gas retention. The objective of this review is to highlight the areas where surfactants are most widely used particularly in the bread industries, their role and mechanism of interaction and their contribution to the quality characteristics of the dough and bread. This review reveals some aspects of surface-active agents regarding its role physiochemical properties of dough that in turn affect the bread characteristics by improving its sensory quality and storage stability.

  12. Low Activity Waste Feed Process Control Strategy

    International Nuclear Information System (INIS)

    STAEHR, T.W.

    2000-01-01

    The primary purpose of this document is to describe the overall process control strategy for monitoring and controlling the functions associated with the Phase 1B high-level waste feed delivery. This document provides the basis for process monitoring and control functions and requirements needed throughput the double-shell tank system during Phase 1 high-level waste feed delivery. This document is intended to be used by (1) the developers of the future Process Control Plan and (2) the developers of the monitoring and control system

  13. Activation mechanism of ammonium ions on sulfidation of malachite (-201) surface by DFT study

    Science.gov (United States)

    Wu, Dandan; Mao, Yingbo; Deng, Jiushuai; Wen, Shuming

    2017-07-01

    The activation mechanism of ammonium ions on the sulfidation of malachite (-201) was determined by density functional theory (DFT) calculations. Results of DFT calculations indicated that interlayer sulfidation occurs during the sulfidation process of malachite (-201). The absorption of both the ammonium ion and sulfide ion on the malachite (-201) surface is stronger than that of sulfur ion. After sulfidation was activated with ammonium ion, the Cu 3d orbital peak is closer to the Fermi level and characterized by a stronger peak value. Therefore, the addition of ammonium ions activated the sulfidation of malachite (-201), thereby improving the flotation performance.

  14. Surface modification of the metal plates using continuous electron beam process (CEBP)

    International Nuclear Information System (INIS)

    Kim, Jisoo; Kim, Jin-Seok; Kang, Eun-Goo; Park, Hyung Wook

    2014-01-01

    Highlights: • We performed surface modification of SM20C, SUS303, and Al6061 using CEBP. • We analyzed surface properties and microstructure after electron-beam irradiation. • The surface quality was improved after electron-beam irradiation. • The surface hardness for SM20C was increased by ∼50% after CEBP irradiation. - Abstract: The finishing process is an important component of the quality-control procedure for final products in manufacturing applications. In this study, we evaluated the performance of continuous electron-beam process as the final process for finishing SM20C (steel alloy), SUS303 (stainless steel alloy), and Al6061 (aluminum alloy) surfaces both on the initially smooth and rough surfaces. Surface modification of the metals was carried out by varying the feed and frequency of the continuous electron-beam irradiation procedure. The resulting surface roughness was examined with respect to the initial surface roughness of the metals. SM20C and SUS303 experienced an improvement in surface roughness, particularly for initially rough surfaces. Continuous electron-beam process produced craters during the process and the effect of this phenomenon on the resulting surface roughness was relatively large with the initially smooth SM20C and SUS303 alloy surfaces. For Al6061, the continuous electron-beam process was effective at improving its surface roughness even with the initially smooth surface under the optimized conditions of process; this was attributed to its low melting point. Scanning electron microscopy was used to identify metallurgical variation within the thin melted and re-solidification layers of the tested alloys. Changes in the surface contact angle and hardness before and after electron-beam irradiation were also examined

  15. Surface modification of the metal plates using continuous electron beam process (CEBP)

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jisoo, E-mail: kimjisu16@unist.ac.kr [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Eonyang-eup, Ulju-gun, Ulsan Metropolitan City 689-798 (Korea, Republic of); Kim, Jin-Seok, E-mail: totoro22@kitech.re.kr [Korea Institute of Industrial Technology (KITECH), KITECH Cheonan Headquarters 35-3 Hongcheon-ri, Ipjang-myeon, Cheonan-si, Chungcheongnam-do 330-825 (Korea, Republic of); Kang, Eun-Goo, E-mail: egkang@kitech.re.kr [Korea Institute of Industrial Technology (KITECH), KITECH Cheonan Headquarters 35-3 Hongcheon-ri, Ipjang-myeon, Cheonan-si, Chungcheongnam-do 330-825 (Korea, Republic of); Park, Hyung Wook, E-mail: hwpark@unist.ac.kr [School of Mechanical and Advanced Materials Engineering, Ulsan National Institute of Science and Technology, UNIST-gil 50, Eonyang-eup, Ulju-gun, Ulsan Metropolitan City 689-798 (Korea, Republic of)

    2014-08-30

    Highlights: • We performed surface modification of SM20C, SUS303, and Al6061 using CEBP. • We analyzed surface properties and microstructure after electron-beam irradiation. • The surface quality was improved after electron-beam irradiation. • The surface hardness for SM20C was increased by ∼50% after CEBP irradiation. - Abstract: The finishing process is an important component of the quality-control procedure for final products in manufacturing applications. In this study, we evaluated the performance of continuous electron-beam process as the final process for finishing SM20C (steel alloy), SUS303 (stainless steel alloy), and Al6061 (aluminum alloy) surfaces both on the initially smooth and rough surfaces. Surface modification of the metals was carried out by varying the feed and frequency of the continuous electron-beam irradiation procedure. The resulting surface roughness was examined with respect to the initial surface roughness of the metals. SM20C and SUS303 experienced an improvement in surface roughness, particularly for initially rough surfaces. Continuous electron-beam process produced craters during the process and the effect of this phenomenon on the resulting surface roughness was relatively large with the initially smooth SM20C and SUS303 alloy surfaces. For Al6061, the continuous electron-beam process was effective at improving its surface roughness even with the initially smooth surface under the optimized conditions of process; this was attributed to its low melting point. Scanning electron microscopy was used to identify metallurgical variation within the thin melted and re-solidification layers of the tested alloys. Changes in the surface contact angle and hardness before and after electron-beam irradiation were also examined.

  16. Capturing Cognitive Processing Time for Active Authentication

    Science.gov (United States)

    2014-02-01

    the password with password -based access control to generate a hardened password [4]. Here, we present a biometric -based active authentication...typing rhythm (CTR), Support Vector Machine (SVM), Behavioral Biometrics 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT UU 18. NUMBER OF... biometrics , extracted from keystroke dynamics, as “something a user is” for active authentication. This scheme performs continual verification in the

  17. In vitro study of proteins surface activity by tritium probe

    International Nuclear Information System (INIS)

    Chernysheva, M.G.; Badun, G.A.

    2010-01-01

    A new technique for in vitro studies of biomacromolecules interactions, their adsorption at aqueous/organic liquid interfaces and distribution in the bulk of liquid/liquid systems was developed. The method includes (1) tritium labeling of biomolecules by tritium thermal activation method and (2) scintillation phase step with organic phase, which can be concerned as a model of cellular membrane. Two globular proteins lysozyme and human serum albumin tested. We have determined the conditions of tritium labeling when labeled by-products can be easy separated by means of dialysis and size-exclusion chromatography. Scintillation phase experiments were conducted for three types of organic liquids. Thus, the influences of the nature of organic phase on proteins adsorption and its distribution in the bulk of aqueous/organic liquid system were determined. It was found that proteins possess high surface activity at aqueous/organic liquid interface. Furthermore, values of hydrophobicity of globular proteins were found by the experiment. (author)

  18. Effect of Surface Diffusion on Transfer Processes in Heterogeneous Systems

    Czech Academy of Sciences Publication Activity Database

    Levdansky, V.V.; Smolík, Jiří; Moravec, Pavel

    2008-01-01

    Roč. 51, 9-10 (2008), s. 2471-2481 ISSN 0017-9310 R&D Projects: GA ČR GA101/05/2214; GA ČR(CZ) GA101/05/2524; GA ČR GA104/07/1093 Institutional research plan: CEZ:AV0Z40720504 Keywords : adsorption * gas flow * surface diffusion Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.894, year: 2008

  19. Prospects of DLC coating as environment friendly surface treatment process.

    Science.gov (United States)

    Kim, S W; Kim, S G

    2011-06-01

    After first commercialization in 90's, the applications of diamond-like carbon (DLC) have been significantly expanded to tool, automobile parts, machineries and moulds to enhance wear and friction properties. Although DLC has many advantages like high hardness, low friction electrical insulating and chemical stability and has the possible market, its application in the field is still very limited due to the gaps of understanding between end-user and developer of its advantage of costing. Recently, one of the most popular issues in the surface modification is providing the long lasting super-hydrophilic or -hydrophobic properties on the material surface for the outdoor usage. A lot of material loss is caused due to water corrosion which has to do with the flow and contacts of water like fuel cell separator and air conditioner parts. The consequence of development of functional surface based on the hydrophilic or hydrophobic design for the important parts would be really helpful for materials to be cleaner and more energy effective. Here, we first reviewed the DLC technology and then examined the kind of surface modification as well as its merits and disadvantage. We also looked at how we can improve super-hydrophilic and super hydrophobic for the DLC coating layer as well as current status of technology and arts of DLC. In the end, we would like to suggest it as one of the environmental friendly industrial technology. Copyright © 2011 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  20. Stability of thin liquid films containing surface active particles

    Science.gov (United States)

    Umashankar, Hariharan; Kalpathy, Sreeram; Dixit, Harish

    2017-11-01

    The stability and dynamics of thin liquid films(industrial settings like coating and printing processes and extraction of oil from porous rocks. In this study a hydrodynamic model is introduced to capture the long term evolution of a Newtonian liquid film containing insoluble surfaceactive particles.We consider here the possibility of four distinct interaction regimes based on the surface rheological effects of the particles, such that either, both or neither of Marangoni and surface viscosity effects would be present at the leading order in the governing equations. The liquid film is bounded by a rigid impermeable solid below and covered by passive air phase above.A standard linear stability analysis and nonlinear simulations are performed on the set of highly coupled partial differential evolution equations. Linear stability analysis gives insights on whether a particular imposed perturbationwavenumber will grow or decay in time and also evaluating the fastest growing wavenumber. Parametric studies for all four regimes provides a strong confirmation that surface viscosity and Marangoni effects are indeed rupture delaying effects.

  1. Nanostructured surface processing by an intense pulsed ion beam irradiation

    International Nuclear Information System (INIS)

    Yatsuzuka, M.; Masuda, T.; Yamasaki, T.; Uchida, H.; Nobuhara, S.; Hashimoto, Y.; Yoshihara, Y.

    1997-01-01

    Metal surface modification by irradiating an intense pulsed ion beam (IPIB) with short pulse width has been studied experimentally. An IPIB irradiation to a target leads to rapid heating above its melting point. After the beam is turned off, the heated region is immediately cooled by thermal conduction at a cooling rate of typically 10 10 K/s. This rapid cooling and resolidification results in generation of nanostructured phase in the top of surface. The typical hydrogen IPIB parameters are 200 kV of energy, 500 A/cm 2 of current density and 70 ns of pulsewidth. The IPIB was irradiated on a pure titanium to generate nanocrystalline phase. The IPIB-irradiated surface was examined with X-ray diffraction, SEM, and HR-TEM. The randomly oriented lattice fringes as well as a halo diffraction pattern are observed in the HR-TEM micrograph of IPIB-irradiated titanium. The average grain size is found to be 32 nanometers

  2. Electrostatic application of antimicrobial sprays to sanitize food handling and processing surfaces for enhanced food safety

    Energy Technology Data Exchange (ETDEWEB)

    Lyons, Shawn M; Harrison, Mark A [Food Science and Technology Department, University of Georgia, Athens, GA, 30602-2610 (United States); Law, S Edward, E-mail: edlaw@engr.uga.edu [Biological and Agricultural Engineering Department, Applied Electrostatics Laboratory www.ael.engr.uga.edu, University of Georgia, Athens, GA, 30602-4435 (United States)

    2011-06-23

    Human illnesses and deaths caused by foodborne pathogens (e.g., Salmonella enterica, Listeria monocytogenes, Escherichia coli O157:H7, etc.) are of increasing concern globally in maintaining safe food supplies. At various stages of the food production, processing and supply chain antimicrobial agents are required to sanitize contact surfaces. Additionally, during outbreaks of contagious pathogenic microorganisms (e.g., H1N1 influenza), public health requires timely decontamination of extensive surfaces within public schools, mass transit systems, etc. Prior publications verify effectiveness of air-assisted, induction-charged (AAIC) electrostatic spraying of various chemical and biological agents to protect on-farm production of food crops...typically doubling droplet deposition efficiency with concomitant increases in biological control efficacy. Within a biosafety facility this present work evaluated the AAIC electrostatic-spraying process for application of antimicrobial liquids onto various pathogen-inoculated food processing and handling surfaces as a food safety intervention strategy. Fluoroanalysis of AAIC electrostatic sprays (-7.2 mC/kg charge-to-mass ratio) showed significantly greater (p<0.05) mass of tracer active ingredient (A.I.) deposited onto target surfaces at various orientations as compared both to a similar uncharged spray nozzle (0 mC/kg) and to a conventional hydraulic-atomizing nozzle. Per unit mass of A.I. dispensed toward targets, for example, A.I. mass deposited by AAIC electrostatic sprays onto difficult to coat backsides was 6.1-times greater than for similar uncharged sprays and 29.0-times greater than for conventional hydraulic-nozzle sprays. Even at the 56% reduction in peracetic acid sanitizer A.I. dispensed by AAIC electrostatic spray applications, they achieved equal or greater CFU population reductions of Salmonella on most target orientations and materials as compared to uncharged sprays and conventional full-rate hydraulic

  3. Electrostatic application of antimicrobial sprays to sanitize food handling and processing surfaces for enhanced food safety

    International Nuclear Information System (INIS)

    Lyons, Shawn M; Harrison, Mark A; Law, S Edward

    2011-01-01

    Human illnesses and deaths caused by foodborne pathogens (e.g., Salmonella enterica, Listeria monocytogenes, Escherichia coli O157:H7, etc.) are of increasing concern globally in maintaining safe food supplies. At various stages of the food production, processing and supply chain antimicrobial agents are required to sanitize contact surfaces. Additionally, during outbreaks of contagious pathogenic microorganisms (e.g., H1N1 influenza), public health requires timely decontamination of extensive surfaces within public schools, mass transit systems, etc. Prior publications verify effectiveness of air-assisted, induction-charged (AAIC) electrostatic spraying of various chemical and biological agents to protect on-farm production of food crops...typically doubling droplet deposition efficiency with concomitant increases in biological control efficacy. Within a biosafety facility this present work evaluated the AAIC electrostatic-spraying process for application of antimicrobial liquids onto various pathogen-inoculated food processing and handling surfaces as a food safety intervention strategy. Fluoroanalysis of AAIC electrostatic sprays (-7.2 mC/kg charge-to-mass ratio) showed significantly greater (p<0.05) mass of tracer active ingredient (A.I.) deposited onto target surfaces at various orientations as compared both to a similar uncharged spray nozzle (0 mC/kg) and to a conventional hydraulic-atomizing nozzle. Per unit mass of A.I. dispensed toward targets, for example, A.I. mass deposited by AAIC electrostatic sprays onto difficult to coat backsides was 6.1-times greater than for similar uncharged sprays and 29.0-times greater than for conventional hydraulic-nozzle sprays. Even at the 56% reduction in peracetic acid sanitizer A.I. dispensed by AAIC electrostatic spray applications, they achieved equal or greater CFU population reductions of Salmonella on most target orientations and materials as compared to uncharged sprays and conventional full-rate hydraulic

  4. Free energy surfaces from nonequilibrium processes without work measurement

    Science.gov (United States)

    Adib, Artur B.

    2006-04-01

    Recent developments in statistical mechanics have allowed the estimation of equilibrium free energies from the statistics of work measurements during processes that drive the system out of equilibrium. Here a different class of processes is considered, wherein the system is prepared and released from a nonequilibrium state, and no external work is involved during its observation. For such "clamp-and-release" processes, a simple strategy for the estimation of equilibrium free energies is offered. The method is illustrated with numerical simulations and analyzed in the context of tethered single-molecule experiments.

  5. Mobility of chemisorbed molecules and surface regeneration of active centers during dehydration of isopropanol on aluminium oxide and aluminosilicate

    International Nuclear Information System (INIS)

    Makhlis, L.A.; Vasserberg, V.Eh.

    1976-01-01

    By a differential isotope method involving 14 C the authors have investigated the surface mobility of chemisorbed molecules of isopropanol during its dehydration in an adsorption layer on aluminium oxide and aluminosilicate. The chemisorbed alcohol molecules possess marked surface mobility which plays a decisive part in the mechanism of surface regeneration of the active catalyst centers in the process of dehydration. The cessation of the reaction long before the adsorbed alcohol is completely used up is explained by the hypothesis that there is local overpopulation of the active sectors by water formed by the reaction; this hinders further surface regeneration and repetition of the elementary events of dehydration

  6. Hazardous drug residue on exterior vial surfaces: evaluation of a commercial manufacturing process.

    Science.gov (United States)

    Power, Luci A; Sessink, Paul J M; Gesy, Kathy; Charbonneau, Flay

    2014-04-01

    Hazardous drug residue on the exterior surface of drug vials poses a potential risk for exposure of health care workers involved in handling these products. The purpose of this article is to heighten the awareness of this serious issue and to evaluate a commercial manufacturing process for removing and containing hazardous drug (HD) residue on exterior vial surfaces. Additionally, findings from this study are interpreted, incorporated into the current body of evidence, and discussed by experts in this field. This study includes separate evaluations for the presence or absence of surface drug contamination on the vials of 3 HD products: 5-fluorouracil, cisplatin, and methotrexate. The drug products were packaged in vials using a patented prewashing/decontamination method, application of a polyvinylchloride (PVC) base, and use of clear glass vials. An additional step of encasing the vial in a shrink-wrapped sheath was used for 5-fluorouracil and cisplatin. Of all 5-fluorouracil (110 vials), methotrexate (60 vials), and cisplatin (60 vials) tested, only 2 had detectable amounts of surface residue. One 5-fluorouracil vial was found to have approximately 4 mg of 5-fluorouracil on the surface of the vial. The second contaminated vial was cisplatin, which was discovered to have 131 ng of platinum, equal to 200 ng of cisplatin or 0.2 μL of cisplatin solution, on the vial sheath. Using validated extraction and analytic methods, all but 2 of the 230 tested vials were found to be free of surface drug contamination. Pharmacy leaders need to take an active role in promoting the need for clean HD vials. Manufacturers should be required to provide their clients with data derived from externally validated analytic studies, reporting the level of HD contamination on the exterior of their vial products.

  7. Design parameters for measurements of local catalytic activity on surfaces

    DEFF Research Database (Denmark)

    Johansson, Martin; Johannessen, Tue; Jørgensen, Jan Hoffmann

    2006-01-01

    Computational fluid dynamics in combination with experiments is used to characterize a gas sampling device for measurements of the local catalytic activity on surfaces. The device basically consists of a quartz capillary mounted concentrically inside an aluminum tube. Reactant gas is blown toward......, the limits of the range in reaction rate, which can be Studied are estimated. (c) 2005 Elsevier B.V. All rights reserved.......Computational fluid dynamics in combination with experiments is used to characterize a gas sampling device for measurements of the local catalytic activity on surfaces. The device basically consists of a quartz capillary mounted concentrically inside an aluminum tube. Reactant gas is blown toward...... limit for the lateral resolution of the measurement, and that a flow rate of the order of 240 (ml/min)(n) is sufficient to achieve this resolution. The sensitivity is reasonable also with high flow rates, due to the presence of a pocket of stagnant gas under the tip of the capillary. Furthermore...

  8. Exotic high activity surface patterns in PtAu nanoclusters

    KAUST Repository

    Mokkath, Junais Habeeb

    2013-05-09

    The structure and chemical ordering of PtAu nanoclusters of 79, 135, and 201 atoms are studied via a combination of a basin hopping atom-exchange technique (to locate the lowest energy homotops at fixed composition), a symmetry orbit technique (to find the high symmetry isomers), and density functional theory local reoptimization (for determining the most stable homotop). The interatomic interactions between Pt and Au are derived from the empirical Gupta potential. The lowest energy structures show a marked tendency toward PtcoreAushell chemical ordering by enrichment of the more cohesive Pt in the core region and of Au in the shell region. We observe a preferential segregation of Pt atoms to (111) facets and Au atoms to (100) facets of the truncated octahedron cluster motif. Exotic surface patterns are obtained particularly for Pt-rich compositions, where Pt atoms are being surrounded by Au atoms. These surface arrangements boost the catalytic activity by creating a large number of active sites. © 2013 American Chemical Society.

  9. Facile preparation of self-healing superhydrophobic CeO2 surface by electrochemical processes

    Science.gov (United States)

    Nakayama, Katsutoshi; Hiraga, Takuya; Zhu, Chunyu; Tsuji, Etsushi; Aoki, Yoshitaka; Habazaki, Hiroki

    2017-11-01

    Herein we report simple electrochemical processes to fabricate a self-healing superhydrophobic CeO2 coating on Type 304 stainless steel. The CeO2 surface anodically deposited on flat stainless steel surface is hydrophilic, although high temperature-sintered and sputter-deposited CeO2 surface was reported to be hydrophobic. The anodically deposited hydrophilic CeO2 surface is transformed to hydrophobic during air exposure. Specific accumulation of contaminant hydrocarbon on the CeO2 surface is responsible for the transformation to hydrophobic state. The deposition of CeO2 on hierarchically rough stainless steel surface produces superhydrophobic CeO2 surface, which also shows self-healing ability; the surface changes to superhydrophilic after oxygen plasma treatment but superhydrophobic state is recovered repeatedly by air exposure. This work provides a facile method for preparing a self-healing superhydrophobic surface using practical electrochemical processes.

  10. Surface Distresses Detection of Pavement Based on Digital Image Processing

    OpenAIRE

    Ouyang , Aiguo; Luo , Chagen; Zhou , Chao

    2010-01-01

    International audience; Pavement crack is the main form of early diseases of pavement. The use of digital photography to record pavement images and subsequent crack detection and classification has undergone continuous improvements over the past decade. Digital image processing has been applied to detect the pavement crack for its advantages of large amount of information and automatic detection. The applications of digital image processing in pavement crack detection, distresses classificati...

  11. The Stellar Imager (SI) Project: Resolving Stellar Surfaces, Interiors, and Magnetic Activity

    Science.gov (United States)

    Carpenter, Kenneth G.; Schrijver, K.; Karovska, M.

    2007-01-01

    The Stellar Imager (SI) is a UV/Optical. Space-Based Interferometer designed to enable 0.1 milli-arcsec (mas) spectral imaging of stellar surfaces and, via asteroseismology, stellar interiors and of the Universe in general. The ultra-sharp images of SI will revolutionize our view of many dynamic astrophysical processes by transforming point sources into extended sources, and snapshots into evolving views. The science of SI focuses on the role of magnetism in the Universe, particularly on magnetic activity on the surfaces of stars like the Sun. Its prime goal is to enable long-term forecasting of solar activity and the space weather that it drives. SI will also revolutionize our understanding of the formation of planetary systems, of the habitability and climatology of distant planets, and of many magneto-hydrodynamically controlled processes in the Universe. In this paper we discuss the science goals, technology needs, and baseline design of the SI mission.

  12. Improvement in Surface Characterisitcs of Polymers for Subsequent Electroless Plating Using Liquid Assisted Laser Processing

    DEFF Research Database (Denmark)

    Marla, Deepak; Zhang, Yang; Jabbaribehnam, Mirmasoud

    2016-01-01

    Metallization of polymers is a widely used process in the electronic industry that involves their surface modification as a pre-treatment step. Laser-based surface modification is one of the commonly used techniques for polymers due to its speed and precision. The process involves laser heating...... of the polymer surface to generate a rough or porous surface. Laser processing in liquid generates superior surface characteristics that result in better metal deposition. In this study, a comparison of the surface characteristics obtained by laser processing in water vis-à-vis air along with the deposition...... characteristics are presented. In addition, a numerical model based on the finite volume method is developed to predict the temperature profile during the process. Based on the model results, it is hypothesized that physical phenomena such as vapor bubble generation and plasma formation may occur in the presence...

  13. Radiotracer studies of the adsorption of surface active substances at aqueous surfaces, 6

    International Nuclear Information System (INIS)

    Tajima, Kazuo

    1976-01-01

    The surface tension and adsorption were observed by the Wilhelmy plate and radiotracer methods at the air-solution interface of an aqueous solution of urea and α-dodecyl-ω-hydroxyhexa(oxyethylene) (D(EO) 6 ). The adsorption of D(EO) 6 was dependent on the concentration of urea below the CMC values, but above the values it was independent of the concentration. Urea adsorption occurs positively for low-surface packing of the poly(oxyethylene) group of D(EO) 6 , but negatively for the closest packing of the group and high concentrations of urea. It was confirmed that D(EO) 6 adsorption took place at the solution surface according to the Gibbs adsorption isotherm, which was taken into account as an activity coefficient in an empirical equation for the interactions of D(EO) 6 and urea in solution. Urea adsorption for the adsorbed monolayer of D(EO) 6 above the CMC value was interpreted assuming that urea, as for the nonionic micelle, was nonpenetrating, which was examined by gel permeation. (auth.)

  14. Metal Catalyzed Fusion: Nuclear Active Environment vs. Process

    Science.gov (United States)

    Chubb, Talbot

    2009-03-01

    To achieve radiationless dd fusion and/or other LENR reactions via chemistry: some focus on environment of interior or altered near-surface volume of bulk metal; some on environment inside metal nanocrystals or on their surface; some on the interface between nanometal crystals and ionic crystals; some on a momentum shock-stimulation reaction process. Experiment says there is also a spontaneous reaction process.

  15. Transforming Internal Activities of Business Process Models to Services Compositions

    NARCIS (Netherlands)

    Dirgahayu, Teduh; Quartel, Dick; van Sinderen, Marten J.; Mostefaoui, S.K.; Maamar, Z.; Ferreira Pires, L.; Hammoudi, S.; Rinderle-Ma, S.; Sadiq, S.; Schulz, K.

    As a service composition language, BPEL imposes as constraint that a business process model should consist only of activities for interacting with other business processes. BPEL provides limited support for implementing internal activities, i.e. activities that are performed by a single business

  16. A program for activation analysis data processing

    International Nuclear Information System (INIS)

    Janczyszyn, J.; Loska, L.; Taczanowski, S.

    1978-01-01

    An ALGOL program for activation analysis data handling is presented. The program may be used either for single channel spectrometry data or for multichannel spectrometry. The calculation of instrumental error and of analysis standard deviation is carried out. The outliers are tested, and the regression line diagram with the related observations are plotted by the program. (author)

  17. Stochastic Modeling and Deterministic Limit of Catalytic Surface Processes

    DEFF Research Database (Denmark)

    Starke, Jens; Reichert, Christian; Eiswirth, Markus

    2007-01-01

    Three levels of modeling, microscopic, mesoscopic and macroscopic are discussed for the CO oxidation on low-index platinum single crystal surfaces. The introduced models on the microscopic and mesoscopic level are stochastic while the model on the macroscopic level is deterministic. It can......, such that in contrast to the microscopic model the spatial resolution is reduced. The derivation of deterministic limit equations is in correspondence with the successful description of experiments under low-pressure conditions by deterministic reaction-diffusion equations while for intermediate pressures phenomena...

  18. Statistical and signal-processing concepts in surface metrology

    International Nuclear Information System (INIS)

    Church, E.L.; Takacs, P.Z.

    1986-03-01

    This paper proposes the use of a simple two-scale model of surface roughness for testing and specifying the topographic figure and finish of synchrotron-radiation mirrors. In this approach the effects of figure and finish are described in terms of their slope distribution and power spectrum, respectively, which are then combined with the system point spread function to produce a composite image. The result can be used to predict mirror performance or to translate design requirements into manufacturing specifications. Pacing problems in this approach are the development of a practical long-trace slope-profiling instrument and realistic statistical models for figure and finish errors

  19. Statistical and signal-processing concepts in surface metrology

    Energy Technology Data Exchange (ETDEWEB)

    Church, E.L.; Takacs, P.Z.

    1986-03-01

    This paper proposes the use of a simple two-scale model of surface roughness for testing and specifying the topographic figure and finish of synchrotron-radiation mirrors. In this approach the effects of figure and finish are described in terms of their slope distribution and power spectrum, respectively, which are then combined with the system point spread function to produce a composite image. The result can be used to predict mirror performance or to translate design requirements into manufacturing specifications. Pacing problems in this approach are the development of a practical long-trace slope-profiling instrument and realistic statistical models for figure and finish errors.

  20. Process & Quality procedures for transport & handling activities

    CERN Document Server

    Böttcher, O

    2002-01-01

    To respect the detailed and complex planning of the LHC installation project it is essential to reduce possible faults in every technical service that can cause delays in the schedule. In order to ensure proper execution of transport and handling activities it is important to get detailed information from the clients as early as possible in order to do the planning and the organisation of the required resources. One procedure that requires greater focus in the future is the preparation of the resources. The goal is to prevent equipment breakdowns and accidents while executing transport and handling activities. In the LEP dismantling project multiple breakdowns of important cranes caused serious problems in the project schedule. For the LHC installation project similar incidents in the reliability of the equipment cannot be accepted because of the high sensitivity of the whole schedule. This paper shall outline the efforts and methods that are put in place in order to meet the LHC installation requirements.

  1. Composition and microstructure alteration of triticale grain surface after processing by enzymes of cellulase complex

    Directory of Open Access Journals (Sweden)

    Elena Kuznetsova

    2016-01-01

    Full Text Available It is found that the pericarp tissue of grain have considerable strength and stiffness, that has an adverse effect on quality of whole-grain bread. Thereby, there exists the need for preliminary chemical and biochemical processing of durable cell walls before industrial use. Increasingly used in the production of bread finds an artificial hybrid of the traditional grain crops of wheat and rye - triticale, grain which has high nutritional value. The purpose of this research was to evaluate the influence of cellulose complex (Penicillium canescens enzymes on composition and microstructure alteration of triticale grain surface, for grain used in baking. Triticale grain was processed by cellulolytic enzyme preparations with different composition (producer is Penicillium canescens. During experiment it is found that triticale grain processing by enzymes of cellulase complex leads to an increase in the content of water-soluble pentosans by 36.3 - 39.2%. The total amount of low molecular sugars increased by 3.8 - 10.5 %. Studies show that under the influence of enzymes the microstructure of the triticale grain surface is changing. Microphotographs characterizing grain surface structure alteration in dynamic (every 2 hours during 10 hours of substrate hydrolysis are shown. It is found that the depth and direction of destruction process for non-starch polysaccharides of grain integument are determined by the composition of the enzyme complex preparation and duration of exposure. It is found, that xylanase involved in the modification of hemicelluloses fiber having both longitudinal and radial orientation. Hydrolysis of non-starch polysaccharides from grain shells led to increase of antioxidant activity. Ferulic acid was identified in alcoholic extract of triticale grain after enzymatic hydrolysis under the influence of complex preparation containing cellulase, xylanase and β-glucanase. Grain processing by independent enzymes containing in complex

  2. Gradient nanostructured surface of a Cu plate processed by incremental frictional sliding

    DEFF Research Database (Denmark)

    Hong, Chuanshi; Huang, Xiaoxu; Hansen, Niels

    2015-01-01

    The flat surface of a Cu plate was processed by incremental frictional sliding at liquid nitrogen temperature. The surface treatment results in a hardened gradient surface layer as thick as 1 mm in the Cu plate, which contains a nanostructured layer on the top with a boundary spacing of the order...

  3. Imaginal, semantic, and surface-level processing of concrete and abstract words: an electrophysiological investigation.

    Science.gov (United States)

    West, W C; Holcomb, P J

    2000-11-01

    Words representing concrete concepts are processed more quickly and efficiently than words representing abstract concepts. Concreteness effects have also been observed in studies using event-related brain potentials (ERPs). The aim of this study was to examine concrete and abstract words using both reaction time (RT) and ERP measurements to determine (1) at what point in the stream of cognitive processing concreteness effects emerge and (2) how different types of cognitive operations influence these concreteness effects. Three groups of subjects performed a sentence verification task in which the final word of each sentence was concrete or abstract. For each group the truthfulness judgment required either (1) image generation, (2) semantic decision, or (3) evaluation of surface characteristics. Concrete and abstract words produced similar RTs and ERPs in the surface task, suggesting that postlexical semantic processing is necessary to elicit concreteness effects. In both the semantic and imagery tasks, RTs were shorter for concrete than for abstract words. This difference was greatest in the imagery task. Also, in both of these tasks concrete words elicited more negative ERPs than abstract words between 300 and 550 msec (N400). This effect was widespread across the scalp and may reflect activation in a linguistic semantic system common to both concrete and abstract words. ERPs were also more negative for concrete than abstract words between 550 and 800 msec. This effect was more frontally distributed and was most evident in the imagery task. We propose that this later anterior effect represents a distinct ERP component (N700) that is sensitive to the use of mental imagery. The N700 may reflect the a access of specific characteristics of the imaged item or activation in a working memory system specific to mental imagery. These results also support the extended dual-coding hypothesis that superior associative connections and the use of mental imagery both contribute

  4. Surface conductivity dependent dynamic behaviour of an ultrafine atmospheric pressure plasma jet for microscale surface processing

    Energy Technology Data Exchange (ETDEWEB)

    Abuzairi, Tomy [Graduate School of Science and Technology, Shizuoka University, Hamamatsu 432-8561 (Japan); Department of Electrical Engineering, Faculty of Engineering, Universitas Indonesia, Depok 16424 (Indonesia); Okada, Mitsuru [Department of Engineering, Shizuoka University, Hamamatsu 432-8561 (Japan); Bhattacharjee, Sudeep [Department of Physics, Indian Institute of Technology, Kanpur 208016 (India); Nagatsu, Masaaki, E-mail: nagatsu.masaaki@shizuoka.ac.jp [Graduate School of Science and Technology, Shizuoka University, Hamamatsu 432-8561 (Japan); Department of Engineering, Shizuoka University, Hamamatsu 432-8561 (Japan); Research Institute of Electronics, Shizuoka University, Hamamatsu 432-8561 (Japan)

    2016-12-30

    Highlights: • Spatio-temporal behaviors of capillary APPJs are studied for various substrates. • Plasma irradiation area depended on the substrate conductivity and permittivity. • Surface irradiation area was significantly broadened in polymer-like substrate. • Effect of applying a substrate bias on the APPJ irradiation area was investigated. - Abstract: An experimental study on the dynamic behaviour of microcapillary atmospheric pressure plasma jets (APPJs) with 5 μm tip size for surfaces of different conductivity is reported. Electrical and spatio-temporal characteristics of the APPJs are monitored using high voltage probe, current monitor and high speed intensified charge couple device camera. From these experimental results, we presented a simple model to understand the electrical discharge characteristics of the capillary APPJs with double electrodes, and estimated the velocity of the ionization fronts in the jet and the electron density to be 3.5–4.2 km/s and 2–7 × 10{sup 17} m{sup −3}. By analyzing the dynamics of the microcapillary APPJs for different substrate materials, it was found that the surface irradiation area strongly depended on the substrate conductivity and permittivity, especially in the case of polymer-like substrate, surface irradiation area was significantly broadened probably due to the repelling behaviour of the plasma jets from the accumulated electrical charges on the polymer surface. The effect of applying a substrate bias in the range from −900 V to +900 V on the plasma irradiation onto the substrates was also investigated. From the knowledge of the present results, it is helpful for choosing the substrate materials for microscale surface modification.

  5. Surface conductivity dependent dynamic behaviour of an ultrafine atmospheric pressure plasma jet for microscale surface processing

    International Nuclear Information System (INIS)

    Abuzairi, Tomy; Okada, Mitsuru; Bhattacharjee, Sudeep; Nagatsu, Masaaki

    2016-01-01

    Highlights: • Spatio-temporal behaviors of capillary APPJs are studied for various substrates. • Plasma irradiation area depended on the substrate conductivity and permittivity. • Surface irradiation area was significantly broadened in polymer-like substrate. • Effect of applying a substrate bias on the APPJ irradiation area was investigated. - Abstract: An experimental study on the dynamic behaviour of microcapillary atmospheric pressure plasma jets (APPJs) with 5 μm tip size for surfaces of different conductivity is reported. Electrical and spatio-temporal characteristics of the APPJs are monitored using high voltage probe, current monitor and high speed intensified charge couple device camera. From these experimental results, we presented a simple model to understand the electrical discharge characteristics of the capillary APPJs with double electrodes, and estimated the velocity of the ionization fronts in the jet and the electron density to be 3.5–4.2 km/s and 2–7 × 10"1"7 m"−"3. By analyzing the dynamics of the microcapillary APPJs for different substrate materials, it was found that the surface irradiation area strongly depended on the substrate conductivity and permittivity, especially in the case of polymer-like substrate, surface irradiation area was significantly broadened probably due to the repelling behaviour of the plasma jets from the accumulated electrical charges on the polymer surface. The effect of applying a substrate bias in the range from −900 V to +900 V on the plasma irradiation onto the substrates was also investigated. From the knowledge of the present results, it is helpful for choosing the substrate materials for microscale surface modification.

  6. REGIONALIZATION OF MANAGEMENT PROCESS BY INNOVATIVE ACTIVITY

    Directory of Open Access Journals (Sweden)

    E. V. Sibirskaia

    2014-01-01

    Full Text Available Summary. In current market conditions, the economy and Russia's accession to international trade scholars and experts from various fields of knowledge paying special attention to a huge set of regional problems. The growing role of regional research determines the level of establishing effective mechanisms for the implementation of the economic interests of actors as well as economic development and improving the quality of human life is the priority objectives of federal, regional and local authorities. Today, the Russian economic science faces a global goal - to develop ways and means of transformation of the Russian economy and bring it to a path of sustainable, innovative development, providing new quality of life. Achieving this goal must surely be a central task of the Russian economics and politics, as in the near future and the long term In article authors opened the maintenance of determinants of innovative development of the territory, mediated by strengthening of regionalization of management by innovative activity: condition of resource and innovative potential; the developed forms and nature of interaction between public authorities of regional level, local community and business; applied forms of integration of subjects of managing for realization of their innovative potential due to expansion of opportunities of participation in the perspective directions of scientific and technical, economic and social development; system of the incentives developing favorable conditions for introduction and development of innovative technologies, and also increases in the enterprise activity, formed by the external institutional environment; regional economic policy as instrument of increase of efficiency of innovative activity.

  7. Optical monitoring of surface processes relevant to thin film growth by chemical vapour deposition

    International Nuclear Information System (INIS)

    Simcock, Michael Neil

    2002-01-01

    This thesis reports on the investigation of the use of reflectance anisotropy spectroscopy (RAS) as an in-situ monitor for the preparation and oxidation of GaAs(100) c(4x4) surfaces using a CVD 2000 MOCVD reactor. These surfaces were oxidised using air. It was found that it was possible to follow surface degradation using RA transients at 2.6eV and 4eV. From this data it was possible to speculate on the nature of the surface oxidation process. A study was performed into the rate of surface degradation under different concentrations of air, it was found that the relation between the air concentration and the surface degradation was complicated but that the behaviour of the first third of the degradation approximated a first order behaviour. An estimation of the activation energy of the process was then made, and an assessment of the potential use of the glove-box for STM studies which is an integral part of the MOCVD equipment was also made. Following this, a description is given of the construction of an interferometer for monitoring thin film growth. An investigation is also described into two techniques designed to evaluate the changes in reflected intensity as measured by an interferometer. The first technique uses an iteration procedure to determine the film thickness from the reflection data. This is done using a Taylor series expansion of the thin film reflection function to iterate for the thickness. Problems were found with the iteration when applied to noisy data, these were solved by using a least squares fit to smooth the data. Problems were also found with the iteration at the turning points these were solved using the derivative of the function and by anticipating the position of the turning points. The second procedure uses the virtual interface method to determine the optical constants of the topmost deposited material, the virtual substrate, and the growth rate. This method is applied by using a Taylor series expansion of the thin film reflection

  8. Surface light scattering: integrated technology and signal processing

    DEFF Research Database (Denmark)

    Lading, L.; Dam-Hansen, C.; Rasmussen, E.

    1997-01-01

    systems representing increasing levels of integration are considered. It is demonstrated that efficient signal and data processing can be achieved by evaluation of the statistics of the derivative of the instantaneous phase of the detector signal. (C) 1997 Optical Society of America....

  9. Surface modification of hydroturbine steel using friction stir processing

    Science.gov (United States)

    Grewal, H. S.; Arora, H. S.; Singh, H.; Agrawal, A.

    2013-03-01

    Friction stir processing (FSP) has proved to be a viable tool for enhancing the mechanical properties of materials, however, the major focus has been upon improving the bulk properties of light metals and their alloys. Hydroturbines are susceptible to damage owing to slurry and cavitation erosion. In this study, FSP of a commonly employed hydroturbine steel, 13Cr4Ni was undertaken. Microstructural characterization of the processed steel was conducted using optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and electron back scatter diffraction (EBSD) techniques. Mechanical characterization of the steel was undertaken in terms of microhardness and resistance to cavitation erosion (CE). FSP resulted in the refinement of the microstructure with reduction in grain size by a factor of 10. EBSD results confirmed the existence of submicron and ultrafine grained microstructure. The microhardness of the steel was found to enhance by 2.6 times after processing. The processed steel also showed 2.4 times higher resistance against cavitation erosion in comparison to unprocessed steel. The primary erosion mechanism for both the steels was identical in nature, with plastic deformation responsible for the loss of material.

  10. The Ice Nucleation Activity of Surface Modified Soot

    Science.gov (United States)

    Häusler, Thomas; Witek, Lorenz; Felgitsch, Laura; Hitzenberger, Regina; Grothe, Hinrich

    2017-04-01

    The ice nucleation efficiency of many important atmospheric particles remains poorly understood. Since soot is ubiquitous in the Earth's troposphere, they might have the potential to significantly impact the Earth's climate (Finlayson-Pitts and Pitts, 2000; Seinfeld and Pandis, 1998). Here we present the ice nucleation activity (INA) in immersion freezing mode of different types of soot. Therefor a CAST (combustion aerosol standard) generator was used to produce different kinds of soot samples. The CAST generator combusts a propane-air-mixture and deposits thereby produced soot on a polyvinyl fluoride filter. By varying the propane to air ratio, the amount of organic portion of the soot can be varied from black carbon (BC) with no organic content to brown carbon (BrC) with high organic content. To investigate the impact of functional sites of ice nuclei (IN), the soot samples were exposed to NO2 gas for a certain amount of time (30 to 360 minutes) to chemically modify the surface. Immersion freezing experiments were carried out in a unique reaction gadget. In this device a water-in-oil suspension (with the soot suspended in the aqueous phase) was cooled till the freezing point and was observed through a microscope (Pummer et al., 2012; Zolles et al., 2015) It was found that neither modified nor unmodified BC shows INA. On the contrary, unmodified BrC shows an INA at -32˚ C, which can be increased up to -20˚ C. The INA of BrC depends on the duration of NO2- exposure. To clarify the characteristics of the surface modifications, surface sensitive analysis like infrared spectroscopy and X-ray photoelectron spectroscopy were carried out. Finlayson-Pitts, B. J. and Pitts, J. N. J.: Chemistry of the Upper and Lower Atmosphere, Elsevier, New York, 2000. Pummer, B. G., Bauer, H., Bernardi, J., Bleicher, S., and Grothe, H.: Suspendable macromolecules are responsible for ice nucleation activity of birch and conifer pollen, Atmos Chem Phys, 12, 2541-2550, 2012. Seinfeld, J

  11. Influence of surface properties on the mechanism of H2S removal by alkaline activated carbons.

    Science.gov (United States)

    Yan, Rong; Chin, Terence; Ng, Yuen Ling; Duan, Huiqi; Liang, David Tee; Tay, Joo Hwa

    2004-01-01

    Alkaline activated carbons are widely used as adsorbents of hydrogen sulfide (H2S), one of the major odorous compounds arising from sewage treatment facilities. Although a number of studies have explored the effects of various parameters, mechanisms of H2S adsorption by alkaline carbons are not yet fully understood. The major difficulty seems to lie in the fact that little is known with certainty about the predominant reactions occurring on the carbon surface. In this study, the surface properties of alkaline activated carbons were systematically investigated to further exploit and better understand the mechanisms of H2S adsorption by alkaline activated carbons. Two commercially available alkaline activated carbons and their representative exhausted samples (8 samples collected at different height of the column after H2S breakthrough tests) were studied. The 8 portions of the exhausted carbon were used to represent the H2S/carbon reaction process. The surface properties of both the original and the exhausted carbons were characterized using the sorption of nitrogen (BET test), surface pH, Boehm titration, thermal and FTIR analysis. Porosity and surface area provide detailed information about the pore structure of the exhausted carbons with respect to the reaction extent facilitating the understanding of potential pore blockages. Results of Boehm titration and FTIR both demonstrate the significant effects of surface functional groups, and identification of oxidation products confirmed the different mechanisms involved with the two carbons. From the DTG curves of thermal analysis, two well-defined peaks representing two products of surface reactions (i.e., sulfur and sulfuric acid) were observed from the 8 exhausted portions with gradually changing patterns coinciding with the extent of the reaction. Surface pH values of the exhausted carbons show a clear trend of pH drop along the reaction extent, while pH around 2 was observed for the bottom of the bed indicating

  12. A high volume cost efficient production macrostructuring process. [for silicon solar cell surface treatment

    Science.gov (United States)

    Chitre, S. R.

    1978-01-01

    The paper presents an experimentally developed surface macro-structuring process suitable for high volume production of silicon solar cells. The process lends itself easily to automation for high throughput to meet low-cost solar array goals. The tetrahedron structure observed is 0.5 - 12 micron high. The surface has minimal pitting with virtually no or very few undeveloped areas across the surface. This process has been developed for (100) oriented as cut silicon. Chemi-etched, hydrophobic and lapped surfaces were successfully texturized. A cost analysis as per Samics is presented.

  13. Active-site titration analysis of surface influence on immobilized Candida antarctica Lipase B activity

    Science.gov (United States)

    Matrix morphology and surface polarity effects were investigated for Candida antarctica lipase B immobilization. Measurements of the amount of lipase immobilized (bicinchoninic acid method) and the catalyst’s tributyrin hydrolysis activity, coupled with a determination of the lipase’s functional fr...

  14. Tribological investigations of the applicability of surface functionalization for dry extrusion processes

    Science.gov (United States)

    Teller, Marco; Prünte, Stephan; Ross, Ingo; Temmler, André; Schneider, Jochen M.; Hirt, Gerhard

    2017-10-01

    Cold extrusion processes are characterized by large relative contact stresses combined with a severe surface enlargement of the workpiece. Under these process conditions a high risk for galling of workpiece material to the tool steel occurs especially in processing of aluminum and aluminum alloys. In order to reduce adhesive wear lubricants for separation of workpiece and tool surfaces are used. As a consequence additional process steps (e.g. preparation and cleaning of workpieces) are necessary. Thus, the realization of a dry forming process is aspired from an environmental and economic perspective. In this paper a surface functionalization with self-assembled-monolayers (SAM) of the tool steels AISI D2 (DIN 1.2379) and AISI H11 (DIN 1.2343) is evaluated by a process-oriented tribological test. The tribological experiment is able to resemble and scale the process conditions of cold extrusion related to relative contact stress and surface enlargement for the forming of pure aluminum (Al99.5). The effect of reduced relative contact stress, surface enlargement and relative velocity on adhesive wear and tool lifetime is evaluated. Similar process conditions are achievable by different die designs with decreased extrusion ratios and adjusted die angles. The effect of surface functionalization critically depends on the substrate material. The different microstructure and the resulting differences in surface chemistry of the two tested tool steels appear to affect the performance of the tool surface functionalization with SAM.

  15. Surface Nano Structures Manufacture Using Batch Chemical Processing Methods for Tooling Applications

    DEFF Research Database (Denmark)

    Tosello, Guido; Calaon, Matteo; Gavillet, J.

    2011-01-01

    The patterning of large surface areas with nano structures by using chemical batch processes to avoid using highenergy intensive nano machining processes was investigated. The capability of different surface treatment methods of creating micro and nano structured adaptable mould inserts for subse...

  16. Modeling cancer registration processes with an enhanced activity diagram.

    Science.gov (United States)

    Lyalin, D; Williams, W

    2005-01-01

    Adequate instruments are needed to reflect the complexity of routine cancer registry operations properly in a business model. The activity diagram is a key instrument of the Unified Modeling Language (UML) for the modeling of business processes. The authors aim to improve descriptions of processes in cancer registration, as well as in other public health domains, through the enhancements of an activity diagram notation within the standard semantics of UML. The authors introduced the practical approach to enhance a conventional UML activity diagram, complementing it with the following business process concepts: timeline, duration for individual activities, responsibilities for individual activities within swimlanes, and descriptive text. The authors used an enhanced activity diagram for modeling surveillance processes in the cancer registration domain. Specific example illustrates the use of an enhanced activity diagram to visualize a process of linking cancer registry records with external mortality files. Enhanced activity diagram allows for the addition of more business concepts to a single diagram and can improve descriptions of processes in cancer registration, as well as in other domains. Additional features of an enhanced activity diagram allow to advance the visualization of cancer registration processes. That, in turn, promotes the clarification of issues related to the process timeline, responsibilities for particular operations, and collaborations among process participants. Our first experiences in a cancer registry best practices development workshop setting support the usefulness of such an approach.

  17. Processing abstract language modulates motor system activity.

    Science.gov (United States)

    Glenberg, Arthur M; Sato, Marc; Cattaneo, Luigi; Riggio, Lucia; Palumbo, Daniele; Buccino, Giovanni

    2008-06-01

    Embodiment theory proposes that neural systems for perception and action are also engaged during language comprehension. Previous neuroimaging and neurophysiological studies have only been able to demonstrate modulation of action systems during comprehension of concrete language. We provide neurophysiological evidence for modulation of motor system activity during the comprehension of both concrete and abstract language. In Experiment 1, when the described direction of object transfer or information transfer (e.g., away from the reader to another) matched the literal direction of a hand movement used to make a response, speed of responding was faster than when the two directions mismatched (an action-sentence compatibility effect). In Experiment 2, we used single-pulse transcranial magnetic stimulation to study changes in the corticospinal motor pathways to hand muscles while reading the same sentences. Relative to sentences that do not describe transfer, there is greater modulation of activity in the hand muscles when reading sentences describing transfer of both concrete objects and abstract information. These findings are discussed in relation to the human mirror neuron system.

  18. Early Student Support for Process Studies of Surface Freshwater Dispersal

    Science.gov (United States)

    2016-06-24

    Sebastian Essink, benefitted from participation in tlte ASIRl research crurses. He has acquired skiUs in both numerical modeling and observational...reactive tracers was examined in a numerical model, subject to different degrees of turbulence. The Ph.D. student, Sebastian Essink, benefitted from...ACCOMPLISHMENTS This grant supported MIT/WHOI Joint Program student, Sebastian Essink, toward a Ph.D. Major Activities 1. Performed modeling

  19. Processing and properties of electrodeposited layered surface coatings

    DEFF Research Database (Denmark)

    Horsewell, Andy

    1998-01-01

    Hard chromium, produced by conventional dir ect curl ent (DC) electrodeposition, cannot be deposited to thicknesses gl enter than about 5 mu m because of the buildup of processing stresses which cause channel cracks in the coating. Much thicker chromium coatings map be produced by depositing a la...... geometry is almost always analogous to bending, and fracture resistance is provided through deviation of the channel crack by weak interfaces, resulting in 'terrace cracking'....

  20. Recycling and surface erosion processes in contemporary tokamaks

    International Nuclear Information System (INIS)

    McCracken, G.M.

    1979-03-01

    A number of global models have recently had considerable success in describing recycling. These are briefly reviewed. It is shown that large gas concentrations can build up in the walls and that these concentrations are seriously affected by erosion and deposition processes and by deliberate gettering with titanium. Finally, the measurement of the concentration of hydrogen in probes is discussed as a means of measuring plasma edge characteristics

  1. Influence of the surface layer characteristics on the regularities of the cutting process

    Directory of Open Access Journals (Sweden)

    Krainev Dmitriy V.

    2017-01-01

    Full Text Available The article considers the influence of the surface layer characteristics on the regularities of the cutting process and the formation of the quality of the surface machined. This effect has been confirmed by the study results of the combined cutting method with advanced plastic deformation (APD. The work estimates the impact of the change in the surface layer properties on the forces and temperature of cutting, stability of the chip formation and quality parameters of the surface machined.

  2. Mechanical stress-controlled tunable active frequency-selective surface

    Science.gov (United States)

    Huang, Bo-Cin; Hong, Jian-Wei; Lo, Cheng-Yao

    2017-01-01

    This study proposes a tunable active frequency-selective surface (AFSS) realized by mechanically expanding or contracting a split-ring resonator (SRR) array. The proposed AFSS transfers mechanical stress from its elastic substrate to the top of the SRR, thereby achieving electromagnetic (EM) modulation without the need for an additional external power supply, meeting the requirements for the target application: the invisibility cloak. The operating mechanism of the proposed AFSS differs from those of other AFSSs, supporting modulations in arbitrary frequencies in the target range. The proposed stress-controlled or strain-induced EM modulation proves the existence of an identical and linear relationship between the strain gradient and the frequency shift, implying its suitability for other EM modulation ranges and applications.

  3. Active tuning of surface phonon polariton resonances via carrier photoinjection

    Science.gov (United States)

    Dunkelberger, Adam D.; Ellis, Chase T.; Ratchford, Daniel C.; Giles, Alexander J.; Kim, Mijin; Kim, Chul Soo; Spann, Bryan T.; Vurgaftman, Igor; Tischler, Joseph G.; Long, James P.; Glembocki, Orest J.; Owrutsky, Jeffrey C.; Caldwell, Joshua D.

    2018-01-01

    Surface phonon polaritons (SPhPs) are attractive alternatives to infrared plasmonics for subdiffractional confinement of infrared light. Localized SPhP resonances in semiconductor nanoresonators are narrow, but that linewidth and the limited extent of the Reststrahlen band limit spectral coverage. To address this limitation, we report active tuning of SPhP resonances in InP and 4H-SiC by photoinjecting free carriers into nanoresonators, taking advantage of the coupling between the carrier plasma and optic phonons to blueshift SPhP resonances. We demonstrate state-of-the-art tuning figures of merit upon continuous-wave excitation (in InP) or pulsed excitation (in 4H-SiC). Lifetime effects cause the tuning to saturate in InP, and carrier redistribution leads to rapid (electronic and phononic excitations.

  4. Low activity resin processing and disposal options review

    International Nuclear Information System (INIS)

    Gardner, F.

    1996-01-01

    New processing options for low activity resin processing and disposal are available. This presentation reviews the economics and technical requirements associated with the following low activity resin processing options. (1) Bulk release resin. (2) Direct disposal. (3) Decontamination and bulk release of cleaned resin. New processing and disposal options have been developed during 1995. Commercial experience with each of these options will be reviewed and the economics associated with the processing method described in detail. Technical requirements for each option will be identified specifying the activity limits and operational requirements for implementation

  5. Covalent organic polymer functionalization of activated carbon surfaces through acyl chloride for environmental clean-up

    DEFF Research Database (Denmark)

    Mines, Paul D.; Thirion, Damien; Uthuppu, Basil

    2017-01-01

    Nanoporous networks of covalent organic polymers (COPs) are successfully grafted on the surfaces of activated carbons, through a series of surface modification techniques, including acyl chloride formation by thionyl chloride. Hybrid composites of activated carbon functionalized with COPs exhibit...

  6. Effect of different machining processes on the tool surface integrity and fatigue life

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Chuan Liang [College of Mechanical and Electrical Engineering, Nanchang University, Nanchang (China); Zhang, Xianglin [School of Materials Science and Engineering, Huazhong University of Science and Technology, Wuhan (China)

    2016-08-15

    Ultra-precision grinding, wire-cut electro discharge machining and lapping are often used to machine the tools in fine blanking industry. And the surface integrity from these machining processes causes great concerns in the research field. To study the effect of processing surface integrity on the fine blanking tool life, the surface integrity of different tool materials under different processing conditions and its influence on fatigue life were thoroughly analyzed in the present study. The result shows that the surface integrity of different materials was quite different on the same processing condition. For the same tool material, the surface integrity on varying processing conditions was quite different too and deeply influenced the fatigue life.

  7. Microscopic investigation of RF surfaces of 3 GHz niobium accelerator cavities following RF processing

    International Nuclear Information System (INIS)

    Graber, J.; Barnes, P.; Flynn, T.; Kirchgessner, J.; Knobloch, J.; Moffat, D.; Muller, H.; Padamsee, H.; Sears, J.

    1993-01-01

    RF processing of Superconducting accelerating cavities is achieved through a change in the electron field emission (FE) characteristics of the RF surface. The authors have examined the RF surfaces of several single-cell 3 GHz cavities, following RF processing, in a Scanning Electron Microscope (SEM). The RF processing sessions included both High Peak Power (P ≤ 50 kW) pulsed processing, and low power (≤ 20 W) continuous wave processing. The experimental apparatus also included a thermometer array on the cavity outer wall, allowing temperature maps to characterize the emission before and after RF processing gains. Multiple sites have been located in cavities which showed improvements in cavity behavior due to RF processing. Several SEM-located sites can be correlated with changes in thermometer signals, indicating a direct relationship between the surface site and emission reduction due to RF processing. Information gained from the SEM investigations and thermometry are used to enhance the theoretical model of RF processing

  8. Effect of particle surface area on ice active site densities retrieved from droplet freezing spectra

    Directory of Open Access Journals (Sweden)

    H. Beydoun

    2016-10-01

    Full Text Available Heterogeneous ice nucleation remains one of the outstanding problems in cloud physics and atmospheric science. Experimental challenges in properly simulating particle-induced freezing processes under atmospherically relevant conditions have largely contributed to the absence of a well-established parameterization of immersion freezing properties. Here, we formulate an ice active, surface-site-based stochastic model of heterogeneous freezing with the unique feature of invoking a continuum assumption on the ice nucleating activity (contact angle of an aerosol particle's surface that requires no assumptions about the size or number of active sites. The result is a particle-specific property g that defines a distribution of local ice nucleation rates. Upon integration, this yields a full freezing probability function for an ice nucleating particle. Current cold plate droplet freezing measurements provide a valuable and inexpensive resource for studying the freezing properties of many atmospheric aerosol systems. We apply our g framework to explain the observed dependence of the freezing temperature of droplets in a cold plate on the concentration of the particle species investigated. Normalizing to the total particle mass or surface area present to derive the commonly used ice nuclei active surface (INAS density (ns often cannot account for the effects of particle concentration, yet concentration is typically varied to span a wider measurable freezing temperature range. A method based on determining what is denoted an ice nucleating species' specific critical surface area is presented and explains the concentration dependence as a result of increasing the variability in ice nucleating active sites between droplets. By applying this method to experimental droplet freezing data from four different systems, we demonstrate its ability to interpret immersion freezing temperature spectra of droplets containing variable particle concentrations. It is shown

  9. Development of sustainable paper coatings using nanoscale industrial surface processing

    DEFF Research Database (Denmark)

    Markert, Frank; Breedveld, Leo; Lahti, Johanna

    in the PlasmaNice project, as environmental and social aspects are addressed using methods like life cycle check (LCC), life cycle assessment (LCA), and industrial risk assessment (RA) within the boundary of an economical production for different market segments. The results are intended to be used partly...... products, and the process and material developers providing new coatings with specific properties. The combination of RA and LCA/LCC within the early stages of product development provide a more holistic approach, It is commonly believed to be also economical beneficial as changes are easier to implement...

  10. The glycoprotein Ib-IX-V complex contributes to tissue factor-independent thrombin generation by recombinant factor VIIa on the activated platelet surface

    NARCIS (Netherlands)

    Weeterings, Cees; de Groot, Philip G.; Adelmeijer, Jelle; Lisman, Ton

    2008-01-01

    Several lines of evidence suggest that recombinant factor VIIa (rFVIIa) is able to activate factor X on an activated platelet, in a tissue factor-independent manner. We hypothesized that, besides the anionic surface, a receptor on the activated platelet surface is involved in this process. Here, we

  11. Air/surface exchange processes of mercury and their linkage to atmospheric pools

    International Nuclear Information System (INIS)

    Bahlmann, Enno; Ebinghaus, Ralf

    2001-01-01

    The atmospheric mercury cycle is strongly linked to the terrestrial, aquatic and biologic cycle of mercury via air/surface exchange processes. In order to quantify mercury fluxes from and to the atmosphere to predict local and regional source contributions the methods for flux measurements as well as the physicochemical factors controlling air/surface exchange processes must be assessed. We will describe methods for the determination of mercury and mercury species in ambient air which are basic for investigation of air/surface exchange processes. Further on we will describe approaches for studying the physicochemical factors controlling this processes by using a new laboratory flux measurement system. (author)

  12. Improvement of Surface Properties of CP-Titanium by Thermo-Chemical Treatment (TCT) Process

    International Nuclear Information System (INIS)

    Jeong, Hyeon-Gyeong; Hur, Bo-Young; Lee, Dong-Geun; Lee, Yong-Tai; Yaskiv, O.

    2011-01-01

    The thermo-chemical treatment (TCT) process was applied to achieve surface hardening of CP titanium. The following three different surface modification conditions were tested so that the best surface hardening process could be selected:(a) PVD, (b) TCT+PVD, and (c) TCT+Aging+PVD. These specimens were tested and analyzed in terms of surface roughness, wear, friction coefficient, and the gradient of hardening from the surface of the matrix. The three test conditions were all beneficial to improve the surface hardness of CP titanium. Moreover, the TCT treated specimens, that is, (b) and (c), showed significantly improved surface hardness and low friction coefficients through the thickness up to 100um. This is due to the functionally gradient hardened surface improvement by the diffused interstitial elements. The hardened surface also showed improvement in bonding between the PVD and TCT surface, and this leads to improvement in wear resistance. However, TCT after aging treatment did not show much improvement in surface properties compared to TCT only. For the best surface hardening on CP titanium, TCT+PVD has advantages in surface durability and economics.

  13. A trial fabrication of activity standard surface sources and positional standard surface sources for an imaging plate system

    International Nuclear Information System (INIS)

    Sato, Yasushi; Hino, Yoshio; Yamada, Takahiro; Matsumoto, Mikio

    2003-01-01

    An imaging plate system can detect low level activity, but quantitative analysis is difficult because there are no adequate standard surface sources. A new fabrication method was developed for standard surface sources by printing on a sheet of paper using an ink-jet printer with inks in which a radioactive material was mixed. The fabricated standard surface sources had high uniformity, high positional resolution arbitrary shapes and a broad intensity range. The standard sources were used for measurement of surface activity as an application. (H. Yokoo)

  14. Synthesis, surface properties and antimicrobial activity of some germanium nonionic surfactants.

    Science.gov (United States)

    Zaki, Mohamed F; Tawfik, Salah M

    2014-01-01

    Esterification reaction between different fatty acid namely; lauric, stearic, oleic and linoleic acids and polyethylene glycol-400 were performed. The produced polyethylene glycol ester were reacted with p-amine benzoic acid followed by condensation reaction with germanium dioxide in presence of sodium carbonate to form desired germinate surfactants. The chemical structures of the synthesized surfactants were determined using different spectra tools. The surface parameter including: the critical micelle concentration (CMC), effectiveness (π(cmc)), efficiency (Pc20), maximum surface excess (Γ(max)) and minimum surface area (A(min)), were calculated from the surface tension measurements. The synthesized surfactants showed higher surface activity. The thermodynamic parameters showed that adsorption and micellization processes are spontaneous. It is clear that the synthesized nonionic surfactants showed their tendency towards adsorption at the interfaces and also micellization in the bulk of their solutions. The synthesized surfactants were tested against different strain of bacteria using inhibition zone diameters. The synthesized surfactants showed good antimicrobial activities against the tested microorganisms including Gram positive, Gram negative as well as fungi. The promising inhibition efficiency of these compounds against the sulfate reducing bacteria facilitates them to be applicable as new categories of sulfate reducing bacteria biocides.

  15. Active and Passive Remote Sensing Data Time Series for Flood Detection and Surface Water Mapping

    Science.gov (United States)

    Bioresita, Filsa; Puissant, Anne; Stumpf, André; Malet, Jean-Philippe

    2017-04-01

    As a consequence of environmental changes surface waters are undergoing changes in time and space. A better knowledge of the spatial and temporal distribution of surface waters resources becomes essential to support sustainable policies and development activities. Especially because surface waters, are not only a vital sweet water resource, but can also pose hazards to human settlements and infrastructures through flooding. Floods are a highly frequent disaster in the world and can caused huge material losses. Detecting and mapping their spatial distribution is fundamental to ascertain damages and for relief efforts. Spaceborne Synthetic Aperture Radar (SAR) is an effective way to monitor surface waters bodies over large areas since it provides excellent temporal coverage and, all-weather day-and-night imaging capabilities. However, emergent vegetation, trees, wind or flow turbulence can increase radar back-scatter returns and pose problems for the delineation of inundated areas. In such areas, passive remote sensing data can be used to identify vegetated areas and support the interpretation of SAR data. The availability of new Earth Observation products, for example Sentinel-1 (active) and Sentinel-2 (passive) imageries, with both high spatial and temporal resolution, have the potential to facilitate flood detection and monitoring of surface waters changes which are very dynamic in space and time. In this context, the research consists of two parts. In the first part, the objective is to propose generic and reproducible methodologies for the analysis of Sentinel-1 time series data for floods detection and surface waters mapping. The processing chain comprises a series of pre-processing steps and the statistical modeling of the pixel value distribution to produce probabilistic maps for the presence of surface waters. Images pre-processing for all Sentinel-1 images comprise the reduction SAR effect like orbit errors, speckle noise, and geometric effects. A modified

  16. Process for dissolving the radioactive corrosion products from internal surfaces in nuclear reactors

    International Nuclear Information System (INIS)

    Brown, W.W.

    1976-01-01

    This invention concerns a process for dissolving in the coolant flowing in a reactor the radioactive substances from the corrosion of the internal surfaces of the reactor to which they cling. When a reactor is operating, the fission occurring in the fuel generates gases and fission substances, such as iodine 131 and 133, cesium 134 and 137, molybdenum 99, xenon 133 and activates the structural materials of the reactor such as nickel by giving off cobalt 58 and similar substances. Under this invention an oxygen rich solution is injected in the reactor coolant after the temperature and pressure reduction stage, during the preparation prior to refuelling and repairs. The oxygen in the solution speeds up the release of cobalt 58 and other radioactive substances from the internal surfaces of the reactor and their dissolving in the oxygenated cold coolant at the start of the cooling procedures of the installation. This allows them to be removed by an ion exchanger before the reactor is emptied. By utilising this process, about half a day may be gained in refuelling time when this has to be done once a week [fr

  17. The process development of laser surface modification of commercially pure titanium (Grade 2) with rhenium

    Science.gov (United States)

    Kobiela, K.; Smolina, I.; Dziedzic, R.; Szymczyk, P.; Kurzynowski, T.; Chlebus, E.

    2016-12-01

    The paper presents the results of the process development of laser surface modification of commercially pure titanium with rhenium. The criterion of the successful/optimal process is the repetitive geometry of the surface, characterized by predictable and repetitive chemical composition over its entire surface as well as special mechanical properties (hardness and wear resistance). The analysis of surface geometry concluded measurements of laser penetration depth and heat affected zone (HAZ), the width of a single track as well as width of a clad. The diode laser installed on the industrial robot carried out the laser treatment. This solution made possible the continuous supply of powder to the substrate during the process. The aim of an investigation is find out the possibility of improving the tribological characteristics of the surface due to the rhenium alloying. The verification of the surface properties (tribological) concluded geometry measurements, microstructure observation, hardness tests and evaluation of wear resistance.

  18. A post-processing study on aluminum surface by fiber laser: Removing face milling patterns

    Science.gov (United States)

    Kayahan, Ersin

    2018-05-01

    The face milling process of the metal surface is a well-known machining process of using rotary cutters to remove material from a workpiece. Flat metal surfaces can be produced by a face milling process. However, in practice, visible, traced marks following the motion of points on the cutter's face are usually apparent. In this study, it was shown that milled patterns can be removed by means of 20 W fiber laser on the aluminum surface (AA7075). Experimental results also showed that roughened and hydrophobic surface can be produced with optimized laser parameters. It is a new approach to remove the patterns from the metal surface and can be explained through roughening by re-melting instead of ablation. The new method is a strong candidate to replace sandblasting the metal surface. It is also cheap and environmentally friendly.

  19. The theory of development of surface morphology by sputter erosion processes

    International Nuclear Information System (INIS)

    Carter, G.; Nobes, M.J.

    1984-01-01

    When a surface is bombarded by an energetic ion flux a rich variety of surface structures are observed to develop at the atomic, microscopic and macroscopic scales. Such structures include elevated, with respect to the surrounding surface, features such as mesas or plateaux, ridges, cones and pyramids and depressed features such as etch pits and cavities. These elementary features may be isolated or in profusion and frequently repetitive patterns of coordinated pyramidal structures, etch pits, surface ledges or facets and ripple or wave-like structures occur. The majority of the features arise rather directly from the erosion action of the sputtering process, particularly from differential erosion processes at different surface localities. The authors outline a general approach to sputter erosion induced surface morphology development based on the concept of the surface as an advancing wave. (Auth.)

  20. DIVERGENT HORIZONTAL SUB-SURFACE FLOWS WITHIN ACTIVE REGION 11158

    Energy Technology Data Exchange (ETDEWEB)

    Jain, Kiran; Tripathy, S. C.; Hill, F., E-mail: kjain@nso.edu, E-mail: stripathy@nso.edu, E-mail: fhill@nso.edu [National Solar Observatory, 950 N Cherry Avenue, Tucson, AZ 85719 (United States)

    2015-07-20

    We measure the horizontal subsurface flow in a fast emerging active region (AR; NOAA 11158) using the ring-diagram technique and the Helioseismic and Magnetic Imager high spatial resolution Dopplergrams. This AR had a complex magnetic structure and displayed significant changes in morphology during its disk passage. Over a period of six days from 2011 February 11 to 16, the temporal variation in the magnitude of the total velocity is found to follow the trend of magnetic field strength. We further analyze regions of individual magnetic polarity within AR 11158 and find that the horizontal velocity components in these sub-regions have significant variation with time and depth. The leading and trailing polarity regions move faster than the mixed-polarity region. Furthermore, both zonal and meridional components have opposite signs for trailing and leading polarity regions at all depths showing divergent flows within the AR. We also find a sharp decrease in the magnitude of total horizontal velocity in deeper layers around major flares. It is suggested that the re-organization of magnetic fields during flares, combined with the sunspot rotation, decreases the magnitude of horizontal flows or that the flow kinetic energy has been converted into the energy released by flares. After the decline in flare activity and sunspot rotation, the flows tend to follow the pattern of magnetic activity. We also observe less variation in the velocity components near the surface but these tend to increase with depth, further demonstrating that the deeper layers are more affected by the topology of ARs.

  1. Surface modification by electrolytic plasma processing for high Nb-TiAl alloys

    Science.gov (United States)

    Gui, Wanyuan; Hao, Guojian; Liang, Yongfeng; Li, Feng; Liu, Xiao; Lin, Junpin

    2016-12-01

    Metal surface modification by electrolytic plasma processing (EPP) is an innovative treatment widely commonly applied to material processing and pretreatment process of coating and galvanization. EPP involves complex processes and a great deal of parameters, such as preset voltage, current, solution temperature and processing time. Several characterization methods are presented in this paper for evaluating the micro-structure surfaces of Ti45Al8Nb alloys: SEM, EDS, XRD and 3D topography. The results showed that the oxide scale and other contaminants on the surface of Ti45Al8Nb alloys can be effectively removed via EPP. The typical micro-crater structure of the surface of Ti45Al8Nb alloys were observed by 3D topography after EPP to find that the mean diameter of the surface structure and roughness value can be effectively controlled by altering the processing parameters. The mechanical properties of the surface according to nanomechanical probe testing exhibited slight decrease in microhardness and elastic modulus after EPP, but a dramatic increase in surface roughness, which is beneficial for further processing or coating.

  2. Fabricating Super-hydrophobic Polydimethylsiloxane Surfaces by a Simple Filler-Dissolved Process

    Science.gov (United States)

    Lin, Yung-Tsan; Chou, Jung-Hua

    2010-12-01

    The self-cleaning effect of super-hydrophobic surfaces has attracted the attention of researchers. Typical ways of manufacturing super-hydrophobic surfaces include the use of either dedicated equipment or a complex chemical process. In this study, a simple innovative filler-dissolved method is developed using mainly powder salt and rinsing to form hydrophobic surfaces. This method can produce large super-hydrophobic surfaces with porous and micro rib surface structures. It can also be applied to curved surfaces, including flexible membranes. The contact angle of the manufactured artificial hydrophobic surface is about 160°. Furthermore, water droplets roll off the surface readily at a sliding angle of less than 5°, resembling the nonwetting lotus like effect.

  3. Functionalized granular activated carbon and surface complexation with chromates and bi-chromates in wastewater

    International Nuclear Information System (INIS)

    Singha, Somdutta; Sarkar, Ujjaini; Luharuka, Pallavi

    2013-01-01

    Cr(VI) is present in the aqueous medium as chromate (CrO 4 2− ) and bi-chromate (HCrO 4 − ). Functionalized granular activated carbons (FACs) are used as adsorbents in the treatment of wastewaters containing hexavalent chromium. The FACs are prepared by chemical modifications of granular activated carbons (GACs) using functionalizing agents like HNO 3 , HCl and HF. The Brunauer, Emmett and Teller surface areas of FAC-HCl (693.5 m 2 /g), FAC-HNO 3 (648.8 m 2 /g) and FAC-HF (726.2 m 2 /g) are comparable to the GAC (777.7 m 2 /g). But, the adsorption capacity of each of the FAC-HNO 3 , FAC-HCl and FAC-HF is found to be higher than the GAC. The functional groups play an important role in the adsorption process and pH has practically no role in this specific case. The FACs have hydrophilic protonated external surfaces in particular, along with the functional surface sites capable to make complexes with the CrO 4 2− and HCrO 4 − present. Surface complex formation is maximized in the order FAC-HNO 3 > FAC-HF > FAC-HCl, in proportion to the total surface acidity. This is also confirmed by the well-known pseudo second-order kinetic model. Physi-sorption equilibrium isotherms are parameterized by using standard Freundlich and Langmuir models. Langmuir fits better. The formation of surface complexes with the functional groups and hexavalent chromium is also revealed in the images of field emission scanning electron micrograph; energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy analysis after adsorption. The intra-particle diffusion is not the only rate-controlling factor. The Boyd's film diffusion model fits very well with R 2 as high as 98.1% for FAC-HNO 3 . This result demonstrates that the functionalization of the GAC by acid treatments would increase the diffusion rate, predominantly with a boundary layer diffusion effect. - Highlights: ► Physico-chemical adsorption using functionalized activated carbon (FACs) is applied. ► FACs

  4. The effect of activation agent on surface morphology, density and porosity of palm shell and coconut shell activated carbon

    Science.gov (United States)

    Leman, A. M.; Zakaria, S.; Salleh, M. N. M.; Sunar, N. M.; Feriyanto, D.; Nazri, A. A.

    2017-09-01

    Activated carbon (AC) has one of the promising alternative technology for filtration and adsorption process. It inexpensive material because the sources is abundant especially in Malaysia. Main purpose of this project is to develop AC by chemical activation process to improve adsorption capacity by improving porosity of AC. AC developed via carbonization using designed burner at temperature of 650°C to 850 °C and activated by Potassium Hydroxide (KOH) in 12 hour and then dried at temperature of 300°C. Characterization and analysis is conducted by Scanning Electron Microscopy (SEM) for surface morphology analysis, Energy Dispersive Spectroscopy (EDS) for composition analysis, density and porosity analysis. Results shows that uneven surface has been observed both of AC and non-AC and also AC shows higher porosity as compared to non-AC materials. Density value of raw material has lower than AC up to 11.67% and 47.54% and porosity of raw material has higher than AC up to 31.45% and 45.69% for palm shell and coconut shell AC. It can be concluded that lower density represent higher porosity of material and higher porosity indicated higher adsorption capacity as well.

  5. Selection of Activities in Dynamic Business Process Simulation

    Directory of Open Access Journals (Sweden)

    Toma Rusinaitė

    2016-06-01

    Full Text Available Maintaining dynamicity of business processes is one of the core issues of today's business as it enables businesses to adapt to constantly changing environment. Upon changing the processes, it is vital to assess possible impact, which is achieved by using simulation of dynamic processes. In order to implement dynamicity in business processes, it is necessary to have an ability to change components of the process (a set of activities, a content of activity, a set of activity sequences, a set of rules, performers and resources or dynamically select them during execution. This problem attracted attention of researches over the past few years; however, there is no proposed solution, which ensures the business process (BP dynamicity. This paper proposes and specifies dynamic business process (DBP simulation model, which satisfies all of the formulated DBP requirements.

  6. Sensitivity study of reduced models of the activated sludge process ...

    African Journals Online (AJOL)

    2009-08-07

    Aug 7, 2009 ... Sensitivity study of reduced models of the activated sludge process, for the purposes of parameter estimation and process optimisation: Benchmark process with ASM1 and UCT reduced biological models. S du Plessis and R Tzoneva*. Department of Electrical Engineering, Cape Peninsula University of ...

  7. Aerobic storage under dynamic conditions in activated sludge processes

    DEFF Research Database (Denmark)

    Majone, M.; Dircks, K.

    1999-01-01

    In activated sludge processes, several plant configurations (like plug-flow configuration of the aeration tanks, systems with selectors, contact-stabilization processes or SBR processes) impose a concentration gradient of the carbon sources to the biomass. As a consequence, the biomass grows unde...

  8. Chemical surface tuning electrocatalysis of redox-active nanoparticles

    DEFF Research Database (Denmark)

    Zhu, Nan; Ulstrup, Jens; Chi, Qijin

    This work focuses on electron transfer (ET) and electrocatalysis of inorganic hybrid Prussian blue nanoparticles (PBNPs, 6 nm) immobilized on different chemical surfaces. Through surface self-assembly chemistry, we have enabled to tune chemical properties of the electrode surface. Stable immobili...

  9. Polyaniline hybridized surface defective ZnO nanorods with long-term stable photoelectrochemical activity

    International Nuclear Information System (INIS)

    Bera, Susanta; Khan, Hasmat; Biswas, Indranil; Jana, Sunirmal

    2016-01-01

    Highlights: • Polyaniline (PANI) hybridized ZnO nanorods was synthesized by solution method. • Surface defects were found in the nanorods. • The hybrid material exhibited an enhancement in visible light absorption. • A long-term stable photoelectrochemical activity of the material was found. • Advancement in the properties would be PANI hybridization and surface defects. - Abstract: We report surfactant/template free precursor solution based synthesis of polyaniline (PANI) hybridized surface defective ZnO nanorods by a two-step process. Initially, ZnO nanorods have been prepared at 95 °C, followed by hybridization (coating) of PANI onto the ZnO via in situ polymerization of aniline monomer, forming ZnO-PANI nanohybrid (ZP). The structural properties of ZP have been analyzed by X-ray diffraction (XRD) and transmission electron microscopic (TEM) studies. The presence of surface defects especially the oxygen vacancies in ZnO has been characterized by photoluminescence emission, high resolution TEM, X-ray photoelectron spectroscopy (XPS) and micro-Raman spectral measurements. The chemical interaction of PANI with ZnO has been examined by Fourier transform infrared (FTIR) and XPS analyses. A significant enhancement in visible absorption of ZP sample is found as evidenced from UV–vis diffused reflectance spectral study. BET nitrogen adsorption-desorption isotherm shows an improved textural property (pore size, pore volume) of ZP. Moreover, a long-term stable photoelectrochemical activity (PEC) of ZP is found compare to pristine ZnO. The synergic effect of PANI hybridization and the presence of surface defects in ZnO NRs can enhance the PEC by prolonging the recombination rate of photogenerated charge carriers. The effect can also provide large number of active sites to make electrolyte diffusion and mass transportation easier in the nanohybrid. This simple synthesis strategy can be adopted for PANI hybridization with different metal oxide semiconductors

  10. Polyaniline hybridized surface defective ZnO nanorods with long-term stable photoelectrochemical activity

    Energy Technology Data Exchange (ETDEWEB)

    Bera, Susanta; Khan, Hasmat [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute (CSIR-CGCRI), 196 Raja S.C. Mullick Road, P.O. Jadavpur University, Kolkata 700 032, West Bengal (India); Biswas, Indranil [Materials Characterization and Instrumentation Division, CSIR-Central Glass and Ceramic Research Institute (CSIR-CGCRI), 196 Raja S.C. Mullick Road, P.O. Jadavpur University, Kolkata 700 032, West Bengal (India); Jana, Sunirmal, E-mail: sjana@cgcri.res.in [Sol-Gel Division, CSIR-Central Glass and Ceramic Research Institute (CSIR-CGCRI), 196 Raja S.C. Mullick Road, P.O. Jadavpur University, Kolkata 700 032, West Bengal (India)

    2016-10-15

    Highlights: • Polyaniline (PANI) hybridized ZnO nanorods was synthesized by solution method. • Surface defects were found in the nanorods. • The hybrid material exhibited an enhancement in visible light absorption. • A long-term stable photoelectrochemical activity of the material was found. • Advancement in the properties would be PANI hybridization and surface defects. - Abstract: We report surfactant/template free precursor solution based synthesis of polyaniline (PANI) hybridized surface defective ZnO nanorods by a two-step process. Initially, ZnO nanorods have been prepared at 95 °C, followed by hybridization (coating) of PANI onto the ZnO via in situ polymerization of aniline monomer, forming ZnO-PANI nanohybrid (ZP). The structural properties of ZP have been analyzed by X-ray diffraction (XRD) and transmission electron microscopic (TEM) studies. The presence of surface defects especially the oxygen vacancies in ZnO has been characterized by photoluminescence emission, high resolution TEM, X-ray photoelectron spectroscopy (XPS) and micro-Raman spectral measurements. The chemical interaction of PANI with ZnO has been examined by Fourier transform infrared (FTIR) and XPS analyses. A significant enhancement in visible absorption of ZP sample is found as evidenced from UV–vis diffused reflectance spectral study. BET nitrogen adsorption-desorption isotherm shows an improved textural property (pore size, pore volume) of ZP. Moreover, a long-term stable photoelectrochemical activity (PEC) of ZP is found compare to pristine ZnO. The synergic effect of PANI hybridization and the presence of surface defects in ZnO NRs can enhance the PEC by prolonging the recombination rate of photogenerated charge carriers. The effect can also provide large number of active sites to make electrolyte diffusion and mass transportation easier in the nanohybrid. This simple synthesis strategy can be adopted for PANI hybridization with different metal oxide semiconductors

  11. Correlation of neural activity with behavioral kinematics reveals distinct sensory encoding and evidence accumulation processes during active tactile sensing.

    Science.gov (United States)

    Delis, Ioannis; Dmochowski, Jacek P; Sajda, Paul; Wang, Qi

    2018-03-23

    Many real-world decisions rely on active sensing, a dynamic process for directing our sensors (e.g. eyes or fingers) across a stimulus to maximize information gain. Though ecologically pervasive, limited work has focused on identifying neural correlates of the active sensing process. In tactile perception, we often make decisions about an object/surface by actively exploring its shape/texture. Here we investigate the neural correlates of active tactile decision-making by simultaneously measuring electroencephalography (EEG) and finger kinematics while subjects interrogated a haptic surface to make perceptual judgments. Since sensorimotor behavior underlies decision formation in active sensing tasks, we hypothesized that the neural correlates of decision-related processes would be detectable by relating active sensing to neural activity. Novel brain-behavior correlation analysis revealed that three distinct EEG components, localizing to right-lateralized occipital cortex (LOC), middle frontal gyrus (MFG), and supplementary motor area (SMA), respectively, were coupled with active sensing as their activity significantly correlated with finger kinematics. To probe the functional role of these components, we fit their single-trial-couplings to decision-making performance using a hierarchical-drift-diffusion-model (HDDM), revealing that the LOC modulated the encoding of the tactile stimulus whereas the MFG predicted the rate of information integration towards a choice. Interestingly, the MFG disappeared from components uncovered from control subjects performing active sensing but not required to make perceptual decisions. By uncovering the neural correlates of distinct stimulus encoding and evidence accumulation processes, this study delineated, for the first time, the functional role of cortical areas in active tactile decision-making. Copyright © 2018 Elsevier Inc. All rights reserved.

  12. Detection analysis of surface hydroxyl active sites and simulation calculation of the surface dissociation constants of aqueous diatomite suspensions

    Science.gov (United States)

    Ma, Shu-Cui; Wang, Zhi-Gang; Zhang, Ji-Lin; Sun, De-Hui; Liu, Gui-Xia

    2015-02-01

    The surface properties of the diatomite were investigated using nitrogen adsorption/deadsorption isotherms, TG-DSC, FTIR, and XPS, and surface protonation-deprotonation behavior was determined by continuous acid-base potentiometric titration technique. The diatomite sample with porous honeycomb structure has a BET specific surface area of 10.21 m2/g and large numbers of surface hydroxyl functional groups (i.e. tbnd Si-OH, tbnd Fe-OH, and tbnd Al-OH). These surface hydroxyls can be protonated or deprotonated depending on the pH of the suspension. The experimental potentiometric data in two different ionic strength solutions (0.1 and 0.05 mol/L NaCl) were fitted using ProtoFit GUI V2.1 program by applying diffuse double layer model (DLM) with three amphoteric sites and minimizing the sum of squares between a dataset derivative function and a model derivative function. The optimized surface parameters (i.e. surface dissociation constants (log K1, log K2) and surface site concentrations (log C)) of the sample were obtained. Based on the optimized surface parameters, the surface species distribution was calculated using Program-free PHREEQC 3.1.2. Thus, this work reveals considerable new information about surface protonation-deprotonation processes and surface adsorptive behaviors of the diatomite, which helps us to effectively use the cheap and cheerful diatomite clay adsorbent.

  13. Assessing the Antimicrobial Activity of Polyisoprene Based Surfaces

    Directory of Open Access Journals (Sweden)

    Hope Badawy

    2015-02-01

    Full Text Available There has been an intense research effort in the last decades in the field of biofouling prevention as it concerns many aspects of everyday life and causes problems to devices, the environment, and human health. Many different antifouling and antimicrobial materials have been developed to struggle against bacteria and other micro- and macro-organism attachment to different surfaces. However the “miracle solution” has still to be found. The research presented here concerns the synthesis of bio-based polymeric materials and the biological tests that showed their antifouling and, at the same time, antibacterial activity. The raw material used for the coating synthesis was natural rubber. The polyisoprene chains were fragmented to obtain oligomers, which had reactive chemical groups at their chain ends, therefore they could be modified to insert polymerizable and biocidal groups. Films were obtained by radical photopolymerization of the natural rubber derived oligomers and their structure was altered, in order to understand the mechanism of attachment inhibition and to increase the efficiency of the anti-biofouling action. The adhesion of three species of pathogenic bacteria and six strains of marine bacteria was studied. The coatings were able to inhibit bacterial attachment by contact, as it was verified that no detectable leaching of toxic molecules occurred.

  14. Surface chemistry of pyrite during the pre-processing for the flotation in alkaline sodium carbonate medium during uranium ore processing

    International Nuclear Information System (INIS)

    Neudert, A.; Sommer, H.; Schubert, H.

    1991-01-01

    It is often necessary during processing of uranium ore to flotate pyrite at sodium carbonate alkaline pH value caused by the subsequent hydrometallurgical process stages. It was found out by ESCA analyses that the pyrite surface changes chemically prior to the addition of flotation agents. FeS 2 becomes FeO within a few hours in the case of storage in process water; limonite and/or geothite result from pyrite. The copper ions of the activator CuSO 4 are exclusively monovalent on the pyrite surface. The resulting heavy metal xanthogenate is Cu(I) xanthogenate. Conclusions are derived for the flotation practice for the intensification of the reagent regime. (orig./HP) [de

  15. Role of activated carbon on micropollutans degradation by different radiation processes

    Directory of Open Access Journals (Sweden)

    Inmaculada Velo Gala

    2015-04-01

    Full Text Available The objective of this study was to analyse the influence of the presence of activated carbon on radiation processes. The triiodinated contrast medium diatrizoate was chosen as the contaminant model. We selected four commercial activated carbons and sixteen gamma radiation-modified carbons derived from these. The different advanced oxidation/reduction processes that have been studied were improved through the addition of activated carbon in the UV light and gamma radiating processes. In the UV/activated carbon process, the synergic activity of the activated carbon is enhanced in the samples with higher percentages of surface oxygen, ester/anhydride groups and carbon atoms with sp2 hybridization. Band gap determination of activated carbons revealed that they behave as semiconductor materials and, therefore, as photoactive materials in the presence of UV radiation, given that all band gap values are <4 eV. We also observed that the gamma radiation treatment reduces the band gap values of the activated carbons and that, in a single series of commercial carbons, lower band gap values correspond to higher contaminant removal rate values. We observed that the activity of the reutilized activated carbons is similar to that of the original carbons. Based on these results, we proposed that the activated carbon acts as a photocatalyst, promoting electrons of the valence band to the conduction band and increasing the generation of HO• radicals in the medium. Similarly, there was a synergic effect made by the presence of activated carbon in gamma radiation system, which favours pollutant removal. This synergic effect is independent of the textural but not the chemical characteristics of the activated carbon, observing a higher synergic activity for carbons with a higher surface content of oxygen, specifically quinone groups. We highlight that the synergic effect of the activated carbon requires adsorbent–adsorbate electrostatic interaction and is absent

  16. Non destructive evaluation of residual stresses in welding and hard-surfacing processes

    International Nuclear Information System (INIS)

    Suarez, J.C.; Fernandez, L.M.; Cruz, C.; Aragon, B.; Merino, F.

    1995-01-01

    In this paper transversal and longitudinal stress profiles in welding and hard-surfacing by welding processes are presented. The stresses were measured by RMS of Barkhausen signal. In this work it is shown that in each case the level of stresses is strongly dependent on the number of weld beads of surfacing layers deposited. The subsequent deposition of new weld beads or surfacing layers produces a stress-relieving effect

  17. Distillation of tar and tar fractions in the presence of surface-active coke

    Energy Technology Data Exchange (ETDEWEB)

    Jaeppelt, A; Klaus, J

    1943-01-01

    The tar obtained by low-temperature carbonization of Upper Silesian gas coke and fractions from this tar were distilled in the presence of different grades of coke dust with varying surface activity; the coke had been activated by steam in the course of its production by low-temperature carbonization. The surface activity of the coke dusts was measured by determining the heat of wetting with C/sub 6/H/sub 6/. Tar and coke dust, both anhydrous, were mixed in a kneading machine in such proportions that the capillaries of the dust were saturated and enough ''externally'' bound tar was present to permit briquetting. The briquets were distilled without cracking and with steam as heating medium. The yield and quality of the distillate depended on the magnitude of the internal surface of the coke dust used; a mixture of a very active coke from brown coal and tar yielded a distillate with Conradson carbon residue of 1.34 percent, asphalt content 6.1 percent and eta/sub 20/ 5.4/sup 0/ E. as compared with C residue of 10.95 percent, asphalt content 33.5 percent and eta/sub 20/ 123.6/sup 0/ E. of the distillate obtained in the absence of surface-active coke. Even higher-boiling fractions can be improved by this treatment, although it is preferable to use oils with an initial boiling point below 300/sup 0/. The ratio of oil to adsorbent is not critical, but better results were obtained with higher percentages of added coke dust. The process in its present form is not suited for the conversion of crude creosote to useful phenols.

  18. Bio-active molecules modified surfaces enhanced mesenchymal stem cell adhesion and proliferation

    International Nuclear Information System (INIS)

    Mobasseri, Rezvan; Tian, Lingling; Soleimani, Masoud; Ramakrishna, Seeram; Naderi-Manesh, Hossein

    2017-01-01

    Surface modification of the substrate as a component of in vitro cell culture and tissue engineering, using bio-active molecules including extracellular matrix (ECM) proteins or peptides derived ECM proteins can modulate the surface properties and thereby induce the desired signaling pathways in cells. The aim of this study was to evaluate the behavior of human bone marrow mesenchymal stem cells (hBM-MSCs) on glass substrates modified with fibronectin (Fn), collagen (Coll), RGD peptides (RGD) and designed peptide (R-pept) as bio-active molecules. The glass coverslips were coated with fibronectin, collagen, RGD peptide and R-peptide. Bone marrow mesenchymal stem cells were cultured on different substrates and the adhesion behavior in early incubation times was investigated using scanning electron microscopy (SEM) and confocal microscopy. The MTT assay was performed to evaluate the effect of different bio-active molecules on MSCs proliferation rate during 24 and 72 h. Formation of filopodia and focal adhesion (FA) complexes, two steps of cell adhesion process, were observed in MSCs cultured on bio-active molecules modified coverslips, specifically in Fn coated and R-pept coated groups. SEM image showed well adhesion pattern for MSCs cultured on Fn and R-pept after 2 h incubation, while the shape of cells cultured on Coll and RGD substrates indicated that they might experience stress condition in early hours of culture. Investigation of adhesion behavior, as well as proliferation pattern, suggests R-peptide as a promising bio-active molecule to be used for surface modification of substrate in supporting and inducing cell adhesion and proliferation. - Highlights: • Bioactive molecules modified surface is a strategy to design biomimicry scaffold. • Bi-functional Tat-derived peptide (R-pept) enhanced MSCs adhesion and proliferation. • R-pept showed similar influences to fibronectin on FA formation and attachment.

  19. Predictive Active Set Selection Methods for Gaussian Processes

    DEFF Research Database (Denmark)

    Henao, Ricardo; Winther, Ole

    2012-01-01

    We propose an active set selection framework for Gaussian process classification for cases when the dataset is large enough to render its inference prohibitive. Our scheme consists of a two step alternating procedure of active set update rules and hyperparameter optimization based upon marginal...... high impact to the classifier decision process while removing those that are less relevant. We introduce two active set rules based on different criteria, the first one prefers a model with interpretable active set parameters whereas the second puts computational complexity first, thus a model...... with active set parameters that directly control its complexity. We also provide both theoretical and empirical support for our active set selection strategy being a good approximation of a full Gaussian process classifier. Our extensive experiments show that our approach can compete with state...

  20. Antibacterial and cytocompatible nanotextured Ti surface incorporating silver via single step hydrothermal processing

    Energy Technology Data Exchange (ETDEWEB)

    Mohandas, Anu; Krishnan, Amit G.; Biswas, Raja; Menon, Deepthy, E-mail: deepthymenon@aims.amrita.edu; Nair, Manitha B., E-mail: manithanair@aims.amrita.edu

    2017-06-01

    Nanosurface modification of Titanium (Ti) implants and prosthesis is proved to enhance osseointegration at the tissue–implant interface. However, many of these products lack adequate antibacterial capability, which leads to implant loosening. As a curative strategy, in this study, nanotextured Ti substrates embedded with silver nanoparticles were developed through a single step hydrothermal processing in an alkaline medium containing silver nitrate at different concentrations (15, 30 and 75 μM). Scanning electron micrographs revealed a non-periodically oriented nanoleafy structure on Ti (TNL) decorated with Ag nanoparticles (nanoAg), which was verified by XPS, XRD and EDS analysis. This TNLAg substrate proved to be mechanically stable upon nanoindentation and nanoscratch tests. Silver ions at detectable levels were released for a period of ~ 28 days only from substrates incorporating higher nanoAg content. The samples demonstrated antibacterial activity towards both Escherichia coli and Staphylococcus aureus, with a more favorable response to the former. Simultaneously, Ti substrates incorporating nanoAg at all concentrations supported the viability, proliferation and osteogenic differentiation of mesenchymal stem cells. Overall, nanoAg incorporation into surface modified Ti via a simple one-step thermochemical method is a favorable strategy for producing implants with dual characteristics of antibacterial activity and cell compatibility. - Highlights: • Nanosilver was incorporated within Ti nanoleafy topography by simple one-step thermochemical method • The nanosurface demonstrated antibacterial activity against gram positive and gram negative bacteria • The nanosurface promoted the viability, proliferation and osteogenic differentiation of mesenchymal stem cells.

  1. Evidence of antibacterial activity on titanium surfaces through nanotextures

    Energy Technology Data Exchange (ETDEWEB)

    Seddiki, O.; Harnagea, C. [INRS – Centre Énergie, Matériaux et Télécommunications, Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2 (Canada); Levesque, L.; Mantovani, D. [Laboratory for Biomaterials and Bioengineering (CRC-I), Dept Min-Met-Materials Engineering and Research Center CHU-Quebec, Laval University, Quebec City (Canada); Rosei, F., E-mail: rosei@emt.inrs.ca [INRS – Centre Énergie, Matériaux et Télécommunications, Boulevard Lionel-Boulet, Varennes, Québec J3X 1S2 (Canada); Center for Self-Assembled Chemical Structures, McGill University, H3A 2K6 Montreal, Quebec (Canada)

    2014-07-01

    Nosocomial infections (Nis) are a major concern for public health. As more and more of the pathogens responsible for these infections are antibiotic resistant, finding new ways to overcome them is a major challenge for biomedical research. We present a method to reduce Nis spreading by hindering bacterial adhesion in its very early stage. This is achieved by reducing the contact interface area between the bacterium and the surface by nanoengineering the surface topography. In particular, we studied the Escheria Coli adhesion on titanium surfaces exhibiting different morphologies, that were obtained by a combination of mechanical polishing and chemical etching. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) characterization revealed that the titanium surface is modified at both micro- and nano-scale. X-ray Photoelectron Spectroscopy (XPS) revealed that the surfaces have the same composition before and after piranha treatment, consisting mainly of TiO{sub 2}. Adhesion tests showed a significant reduction in bacterial accumulation on nanostructured surfaces that had the lowest roughness over large areas. SEM images acquired after bacterial culture on different titanium substrates confirmed that the polished titanium surface treated one hour in a piranha solution at a temperature of 25 °C has the lowest bacterial accumulation among all the surfaces tested. This suggests that the difference observed in bacterial adhesion between the different surfaces is due primarily to surface topography.

  2. Evidence of antibacterial activity on titanium surfaces through nanotextures

    International Nuclear Information System (INIS)

    Seddiki, O.; Harnagea, C.; Levesque, L.; Mantovani, D.; Rosei, F.

    2014-01-01

    Nosocomial infections (Nis) are a major concern for public health. As more and more of the pathogens responsible for these infections are antibiotic resistant, finding new ways to overcome them is a major challenge for biomedical research. We present a method to reduce Nis spreading by hindering bacterial adhesion in its very early stage. This is achieved by reducing the contact interface area between the bacterium and the surface by nanoengineering the surface topography. In particular, we studied the Escheria Coli adhesion on titanium surfaces exhibiting different morphologies, that were obtained by a combination of mechanical polishing and chemical etching. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) characterization revealed that the titanium surface is modified at both micro- and nano-scale. X-ray Photoelectron Spectroscopy (XPS) revealed that the surfaces have the same composition before and after piranha treatment, consisting mainly of TiO 2 . Adhesion tests showed a significant reduction in bacterial accumulation on nanostructured surfaces that had the lowest roughness over large areas. SEM images acquired after bacterial culture on different titanium substrates confirmed that the polished titanium surface treated one hour in a piranha solution at a temperature of 25 °C has the lowest bacterial accumulation among all the surfaces tested. This suggests that the difference observed in bacterial adhesion between the different surfaces is due primarily to surface topography.

  3. Reduction of Surface Roughness by Means of Laser Processing over Additive Manufacturing Metal Parts.

    Science.gov (United States)

    Alfieri, Vittorio; Argenio, Paolo; Caiazzo, Fabrizia; Sergi, Vincenzo

    2016-12-31

    Optimization of processing parameters and exposure strategies is usually performed in additive manufacturing to set up the process; nevertheless, standards for roughness may not be evenly matched on a single complex part, since surface features depend on the building direction of the part. This paper aims to evaluate post processing treating via laser surface modification by means of scanning optics and beam wobbling to process metal parts resulting from selective laser melting of stainless steel in order to improve surface topography. The results are discussed in terms of roughness, geometry of the fusion zone in the cross-section, microstructural modification, and microhardness so as to assess the effects of laser post processing. The benefits of beam wobbling over linear scanning processing are shown, as heat effects in the base metal are proven to be lower.

  4. One-process fabrication of metal hierarchical nanostructures with rich nanogaps for highly-sensitive surface-enhanced Raman scattering

    International Nuclear Information System (INIS)

    Liu, Gui-qiang; Yu, Mei-dong; Liu, Zheng-qi; Liu, Xiao-shan; Huang, Shan; Pan, Ping-ping; Wang, Yan; Liu, Mu-lin; Gu, Gang

    2015-01-01

    One-process fabrication of highly active and reproducible surface-enhanced Raman scattering (SERS) substrates via ion beam deposition is reported. The fabricated metal–dielectric–metal (MDM) hierarchical nanostructure possesses rich nanogaps and a tunable resonant cavity. Raman scattering signals of analytes are dramatically strengthened due to the strong near-field coupling of localized surface plasmon resonances (LSPRs) and the strong interaction of LSPRs of metal NPs with surface plasmon polaritons (SPPs) on the underlying metal film by crossing over the dielectric spacer. The maximum Raman enhancement for the highest Raman peak at 1650 cm −1 is 13.5 times greater than that of a single metal nanoparticle (NP) array. Moreover, the SERS activity can be efficiently tailored by varying the size and number of voids between adjacent metal NPs and the thickness of the dielectric spacer. These findings may broaden the scope of SERS applications of MDM hierarchical nanostructures in biomedical and analytical chemistry. (paper)

  5. An Experimental Study of the Dropwise Condensation on Physically Processed Surface

    International Nuclear Information System (INIS)

    Choi, Jaeyoung; Chang, Soonheung; Watanabe, N.; Sambuichi, T.; Shiota, D.; Aritomi, M.

    2013-01-01

    Recent research by Kawakubo et al. derived empirical condensation heat transfer correlation suitable for wider range of operating condition in presence of non-condensable gas. However, their proposals of PCCS are focused on plane tube surface. To design better PCCS heat exchanger with high heat transfer coefficient new treatment on condensation surface can be considered in order to maintain dropwise condensation, the heat transfer coefficient of which has an order of magnitude larger than those of film condensation. Advanced research measure dropwise condensation heat transfer coefficient of Au and Cr coated surface based on number of droplet and droplet growth rate. However, coated surface is not desirable in power plant due to its duration of few years. On the other hand, physical processing (micro holes and patterns) on stainless steel and titanium surface is expected to perform better heat transfer, also is durable for the whole reactor lifetime. Since there is no published research about dropwise condensation for physically processed surface on SUS and Ti, the purposes of this research are to measure the condensation heat transfer coefficient and analyze its mechanism of enhanced heat transfer of treated SUS and Ti commonly used to nuclear plant. In the comparison of theoretical equation and experiment, it shows same result that heat transfer coefficient is proportional to maximum droplet diameter power to -0.321. Moreover, in the comparison of bare and processed surface, heat transfer coefficient decreases in processed surface

  6. Numerical study on formation process of helical nonneutral plasmas using electron injection from outside magnetic surfaces

    International Nuclear Information System (INIS)

    Nakamura, Kazutaka; Himura, Haruhiko; Masamune, Sadao; Sanpei, Akio; Isobe, Mitsutaka

    2009-01-01

    In order to investigate the formation process of helical nonneutral plasmas, we calculate the orbits of electron injected in the stochastic magnetic field when the closed helical magnetic surfaces is correspond with the equipotential surfaces. Contrary to the experimental observation, there are no electrons inward penetrating. (author)

  7. An improved process for the surface modification of SiO2 nanoparticles

    KAUST Repository

    Livi, Sé bastien; Giannelis, Emmanuel P.

    2012-01-01

    A phosphonium ionic liquid is used as an activator of silanol groups to improve the surface functionalization of silica nanoparticles with fluorosilanes in supercritical CO 2. © 2012 The Royal Society of Chemistry.

  8. Upper Meter Processes: Short Wind Waves, Surface Flow, and Micro-Turbulence

    National Research Council Canada - National Science Library

    Jaehne, Bernd

    2000-01-01

    .... Since ground truth of the sea surface is still widely missing, a better understanding of the physics of these upper meter processes is of very important for the study of air-sea gas and momentum...

  9. Evaluation of optical functional surfaces on the injection moulding insert by micro milling process

    DEFF Research Database (Denmark)

    Li, Dongya; Davoudinejad, Ali; Zhang, Yang

    2017-01-01

    This study presents the optimization of micro milling process for manufacturing injection moulding inserts with an optical functionalsurface. The objective is the optimal surface functionality. Micro ridges were used as the microstructures to realize the function to generate contrast between...

  10. Cold pressure welding of aluminium-steel blanks: Manufacturing process and electrochemical surface preparation

    Science.gov (United States)

    Schmidt, Hans Christian; Homberg, Werner; Orive, Alejandro Gonzalez; Grundmeier, Guido; Hordych, Illia; Maier, Hans Jürgen

    2018-05-01

    In this study the manufacture of aluminium-steel blanks by cold pressure welding and their preparation for a welding process through electrochemical surface treatment are investigated and discussed. The cold pressure welding process was done with an incremental rolling tool that allows for the partial pressure welding of two blanks along a prepared path. The influence of the surface preparation by electrochemical deposition of bond promoting organosilane-based agents and roughening on a nano-scale is investigated and compared to conventional surface treatments. Coating the surfaces with a thin organosilane-based film incorporating specific functional groups should promote additional bonding between the mating oxide layers; its influence on the total weld strength is studied. Pressure welding requires suitable process strategies, and the current advances in the proposed incremental rolling process for the combination of mild steel and aluminium are presented.

  11. Simulation of dynamic processes when machining transition surfaces of stepped shafts

    Science.gov (United States)

    Maksarov, V. V.; Krasnyy, V. A.; Viushin, R. V.

    2018-03-01

    The paper addresses the characteristics of stepped surfaces of parts categorized as "solids of revolution". It is noted that in the conditions of transition modes during the switch to end surface machining, there is cutting with varied load intensity in the section of the cut layer, which leads to change in cutting force, onset of vibrations, an increase in surface layer roughness, a decrease of size precision, and increased wear of a tool's cutting edge. This work proposes a method that consists in developing a CNC program output code that allows one to process complex forms of stepped shafts with only one machine setup. The authors developed and justified a mathematical model of a technological system for mechanical processing with consideration for the resolution of tool movement at the stages of transition processes to assess the dynamical stability of a system in the process of manufacturing stepped surfaces of parts of “solid of revolution” type.

  12. Fabrication of superhydrophobic wood surfaces via a solution-immersion process

    Science.gov (United States)

    Liu, Changyu; Wang, Shuliang; Shi, Junyou; Wang, Chengyu

    2011-11-01

    Superhydrophobic wood surfaces were fabricated from potassium methyl siliconate (PMS) through a convenient solution-immersion method. The reaction involves a hydrogen bond assembly and a polycondensation process. The silanol was formed by reacting PMS aqueous solution with CO2, which was assembled on the wood surface via hydrogen bonds with the wood surface -OH groups. The polymethylsilsesquioxane coating was obtained through the polycondensation reaction of the hydroxyl between wood and silanol. The morphology of products were characterized using a scanning electron microscope (SEM), the surface chemical composition was determined using energy dispersive X-ray analysis (EDXA), Fourier transform infrared spectroscopy (FT-IR), thermogravimetry (TGA) and contact angle measurement. Analytical results revealed that rough protuberances uniformly covered the wood surface, thus transforming the wood surface from hydrophilic to superhydrophobic. The water contact angle of the superhydrophobic wood surface was about 153° and a sliding angle was 4.6°.

  13. Surface Engineering for Bone Implants: A Trend from Passive to Active Surfaces

    Directory of Open Access Journals (Sweden)

    John Jansen

    2012-07-01

    Full Text Available The mechanical and biological properties of bone implants need to be optimal to form a quick and firm connection with the surrounding environment in load bearing applications. Bone is a connective tissue composed of an organic collagenous matrix, a fine dispersion of reinforcing inorganic (calcium phosphate nanocrystals, and bone-forming and -degrading cells. These different components have a synergistic and hierarchical structure that renders bone tissue properties unique in terms of hardness, flexibility and regenerative capacity. Metallic and polymeric materials offer mechanical strength and/or resilience that are required to simulate bone tissue in load-bearing applications in terms of maximum load, bending and fatigue strength. Nevertheless, the interaction between devices and the surrounding tissue at the implant interface is essential for success or failure of implants. In that respect, coatings can be applied to facilitate the process of bone healing and obtain a continuous transition from living tissue to the synthetic implant. Compounds that are inspired by inorganic (e.g., hydroxyapatite crystals or organic (e.g., collagen, extracellular matrix components, enzymes components of bone tissue, are the most obvious candidates for application as implant coating to improve the performance of bone implants. This review provides an overview of recent trends and strategies in surface engineering that are currently investigated to improve the biological performance of bone implants in terms of functionality and biological efficacy.

  14. The role of original surface roughness in laser-induced periodic surface structure formation process on poly-carbonate films

    International Nuclear Information System (INIS)

    Csete, M.; Hild, S.; Plettl, A.; Ziemann, P.; Bor, Zs.; Marti, O.

    2004-01-01

    Poly-carbonate films containing different types of original surface roughness were illuminated by a polarized ArF excimer laser beam having a fluence of 4 mJ/cm 2 . Atomic force microscopy was applied to study the laser-induced periodic surface structure formation process at 0 deg. , 30 deg. and 45 deg. angles of incidence. The effect of initial surface structures on the intensity distribution was investigated in cases of: (a) grains on oriented and amorphous thick films; (b) holes on thin spin-coated films; and (c) nanoparticles arranged along micrometer long sides of hexagons below the spin-coated films. The presence of the scattering objects caused symmetry breaking, if the samples were illuminated by oblique incident 's' polarized beam. The Fourier analysis of the AFM pictures has shown the competition of structures having different periods. The characteristic of the permanent surface patterns proved that the interference of the incoming beam and the beams scattered on previously existing structures is the LIPSS generating feedback process. Ring-shaped structures having 228 nm diameter were produced

  15. Effect of Surface Densification on the Microstructure and Mechanical Properties of Powder Metallurgical Gears by Using a Surface Rolling Process

    Directory of Open Access Journals (Sweden)

    Jingguang Peng

    2016-10-01

    Full Text Available Powder metallurgy (PM components are widely used in the auto industry due to the advantage of net-shape forming, low cost, and high efficiency. Still, usage of PM components is limited in the auto industry when encountering rigorous situations, like heavy load, due to lower strength, hardness, wear resistance, and other properties compared to wrought components due to the existence of massive pores in the PM components. In this study, through combining the powder metallurgy process and rolling process, the pores in the PM components were decreased and a homogenous densified layer was formed on the surface, which resulted in the enhancement of the strength, hardness, wear resistance, and other properties, which can expand its range of application. In this paper, we study the impact of different rolling feeds on the performance of the components’ surfaces. We found that with the increase of the rolling feed, the depth of the densified layer increased.

  16. Development of Statistical Process Control Methodology for an Environmentally Compliant Surface Cleaning Process in a Bonding Laboratory

    Science.gov (United States)

    Hutchens, Dale E.; Doan, Patrick A.; Boothe, Richard E.

    1997-01-01

    Bonding labs at both MSFC and the northern Utah production plant prepare bond test specimens which simulate or witness the production of NASA's Reusable Solid Rocket Motor (RSRM). The current process for preparing the bonding surfaces employs 1,1,1-trichloroethane vapor degreasing, which simulates the current RSRM process. Government regulations (e.g., the 1990 Amendments to the Clean Air Act) have mandated a production phase-out of a number of ozone depleting compounds (ODC) including 1,1,1-trichloroethane. In order to comply with these regulations, the RSRM Program is qualifying a spray-in-air (SIA) precision cleaning process using Brulin 1990, an aqueous blend of surfactants. Accordingly, surface preparation prior to bonding process simulation test specimens must reflect the new production cleaning process. The Bonding Lab Statistical Process Control (SPC) program monitors the progress of the lab and its capabilities, as well as certifies the bonding technicians, by periodically preparing D6AC steel tensile adhesion panels with EA-91 3NA epoxy adhesive using a standardized process. SPC methods are then used to ensure the process is statistically in control, thus producing reliable data for bonding studies, and identify any problems which might develop. Since the specimen cleaning process is being changed, new SPC limits must be established. This report summarizes side-by-side testing of D6AC steel tensile adhesion witness panels and tapered double cantilevered beams (TDCBs) using both the current baseline vapor degreasing process and a lab-scale spray-in-air process. A Proceco 26 inches Typhoon dishwasher cleaned both tensile adhesion witness panels and TDCBs in a process which simulates the new production process. The tests were performed six times during 1995, subsequent statistical analysis of the data established new upper control limits (UCL) and lower control limits (LCL). The data also demonstrated that the new process was equivalent to the vapor

  17. Process of activation of a palladium catalyst system

    Science.gov (United States)

    Sobolevskiy, Anatoly [Orlando, FL; Rossin, Joseph A [Columbus, OH; Knapke, Michael J [Columbus, OH

    2011-08-02

    Improved processes for activating a catalyst system used for the reduction of nitrogen oxides are provided. In one embodiment, the catalyst system is activated by passing an activation gas stream having an amount of each of oxygen, water vapor, nitrogen oxides, and hydrogen over the catalyst system and increasing a temperature of the catalyst system to a temperature of at least 180.degree. C. at a heating rate of from 1-20.degree./min. Use of activation processes described herein leads to a catalyst system with superior NOx reduction capabilities.

  18. Detection analysis of surface hydroxyl active sites and simulation calculation of the surface dissociation constants of aqueous diatomite suspensions

    International Nuclear Information System (INIS)

    Ma, Shu-Cui; Wang, Zhi-Gang; Zhang, Ji-Lin; Sun, De-Hui; Liu, Gui-Xia

    2015-01-01

    Highlights: • To examine surface hydroxyl functional groups of the calcined diatomite by TGA-DSC, FTIR, and XPS. • To calculate the optimized log K 1 , log K 2 and log C values and the surface species distribution of each surface reactive site using ProtoFit and PHREEQC, respectively. - Abstract: The surface properties of the diatomite were investigated using nitrogen adsorption/deadsorption isotherms, TG-DSC, FTIR, and XPS, and surface protonation–deprotonation behavior was determined by continuous acid–base potentiometric titration technique. The diatomite sample with porous honeycomb structure has a BET specific surface area of 10.21 m 2 /g and large numbers of surface hydroxyl functional groups (i.e. ≡Si-OH, ≡Fe-OH, and ≡Al-OH). These surface hydroxyls can be protonated or deprotonated depending on the pH of the suspension. The experimental potentiometric data in two different ionic strength solutions (0.1 and 0.05 mol/L NaCl) were fitted using ProtoFit GUI V2.1 program by applying diffuse double layer model (DLM) with three amphoteric sites and minimizing the sum of squares between a dataset derivative function and a model derivative function. The optimized surface parameters (i.e. surface dissociation constants (log K 1 , log K 2 ) and surface site concentrations (log C)) of the sample were obtained. Based on the optimized surface parameters, the surface species distribution was calculated using Program-free PHREEQC 3.1.2. Thus, this work reveals considerable new information about surface protonation–deprotonation processes and surface adsorptive behaviors of the diatomite, which helps us to effectively use the cheap and cheerful diatomite clay adsorbent

  19. Detection analysis of surface hydroxyl active sites and simulation calculation of the surface dissociation constants of aqueous diatomite suspensions

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Shu-Cui [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province, Changchun University of Science and Technology, Changchun 130022 (China); Wang, Zhi-Gang [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Zhang, Ji-Lin, E-mail: zjl@ciac.ac.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Sun, De-Hui [Changchun Institute Technology, Changchun 130012 (China); Liu, Gui-Xia, E-mail: liuguixia22@163.com [Key Laboratory of Applied Chemistry and Nanotechnology at Universities of Jilin Province, Changchun University of Science and Technology, Changchun 130022 (China)

    2015-02-01

    Highlights: • To examine surface hydroxyl functional groups of the calcined diatomite by TGA-DSC, FTIR, and XPS. • To calculate the optimized log K{sub 1}, log K{sub 2} and log C values and the surface species distribution of each surface reactive site using ProtoFit and PHREEQC, respectively. - Abstract: The surface properties of the diatomite were investigated using nitrogen adsorption/deadsorption isotherms, TG-DSC, FTIR, and XPS, and surface protonation–deprotonation behavior was determined by continuous acid–base potentiometric titration technique. The diatomite sample with porous honeycomb structure has a BET specific surface area of 10.21 m{sup 2}/g and large numbers of surface hydroxyl functional groups (i.e. ≡Si-OH, ≡Fe-OH, and ≡Al-OH). These surface hydroxyls can be protonated or deprotonated depending on the pH of the suspension. The experimental potentiometric data in two different ionic strength solutions (0.1 and 0.05 mol/L NaCl) were fitted using ProtoFit GUI V2.1 program by applying diffuse double layer model (DLM) with three amphoteric sites and minimizing the sum of squares between a dataset derivative function and a model derivative function. The optimized surface parameters (i.e. surface dissociation constants (log K{sub 1}, log K{sub 2}) and surface site concentrations (log C)) of the sample were obtained. Based on the optimized surface parameters, the surface species distribution was calculated using Program-free PHREEQC 3.1.2. Thus, this work reveals considerable new information about surface protonation–deprotonation processes and surface adsorptive behaviors of the diatomite, which helps us to effectively use the cheap and cheerful diatomite clay adsorbent.

  20. Effect of electropulsing on surface mechanical properties and microstructure of AISI 304 stainless steel during ultrasonic surface rolling process

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Haibo [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China); Song, Guolin [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Tang, Guoyi, E-mail: tanggy@mail.tsinghua.edu.cn [Advanced Materials Institute, Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055 (China); Key Laboratory of Advanced Materials, Tsinghua University, Beijing 100084 (China)

    2016-04-26

    The present work integrates 3D digital optical microscopy (OM), nano-indentation, X-ray diffraction (XRD), scanning electron microscopy (SEM) with electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM) to systematically investigate the effect of electropulsing on the surface mechanical properties and microstructure of AISI 304 stainless steel during the ultrasonic surface rolling process (USRP). Compared with the original USRP, the introduction of electropulsing with optimal parameters can effectively facilitate surface crack healing and improve surface hardness and wear resistance dramatically, and the residual compressive stress is further enhanced. Meanwhile, more martensite phase and fewer deformation twins can be found in the strengthened layer. Rapid improvement of the surface mechanical properties should be attributed to the ultra-refined grains, accelerated martensitic phase transformation and suppressed deformation twining induced by the coupling effect of USRP and electropulsing. The high strain rate given by USRP, increased stacking fault energy and accelerated dislocation mobility caused by electropulsing are likely the primary intrinsic reasons for the observed phenomena.

  1. Enhanced visible light-induced photocatalytic activity of surface-modified BiOBr with Pd nanoparticles

    Science.gov (United States)

    Meng, Xiangchao; Li, Zizhen; Chen, Jie; Xie, Hongwei; Zhang, Zisheng

    2018-03-01

    Palladium nanoparticles well-dispersed on BiOBr surfaces were successfully prepared via a two-step process, namely hydrothermal synthesis of BiOBr followed by photodeposition of palladium. Surface-exposed palladium nanoparticles may improve the harvesting capacity of visible light photons via the surface plasmonic resonance effect to produce extra electrons. Palladium is an excellent electron acceptor, and therefore favours the separation of photogenerated electron/hole pairs. As a result, palladium significantly improves the photocatalytic activity of BiOBr in the removal of organic pollutants (phenol) under visible light irradiation. In addition to as-prepared samples which were comprehensively characterized, the mechanism for the enhancement via the deposition of palladium nanoparticles was also proposed based on results. This work may serve as solid evidence to confirm that surface-deposited palladium nanoparticles are capable of improving photocatalytic activity, and that photodeposition may be an effective approach to load metal nanoparticles onto a surface.

  2. Substrate integrated ferrite phase shifters and active frequency selective surfaces

    International Nuclear Information System (INIS)

    Cahill, B.M.

    2002-01-01

    There are two distinct parts to this thesis; the first investigates the use of ferrite tiles in the construction of printed phase shifting transmission lines, culminating in the design of two compact electromagnetic controlled beam steered patch and slot antenna arrays. The second part investigates the use of active frequency selective surfaces (AFSS), which are later used to cover a uPVC constructed enclosure. Field intensity measurements are taken from within the enclosure to determine the dynamic screening effectiveness. Trans Tech G-350 Ferrite is investigated to determine its application in printed microstrip and stripline phase shifting transmission lines. 50-Ohm transmission lines are constructed using the ferrite tile and interfaced to Rogers RT Duroid 5870 substrate. Scattering parameter measurements are made under the application of variable magnetic fields to the ferrite. Later, two types of planar microwave beam steering antennas are constructed. The first uses the ferrites integrated into the Duroid as microstrip lines with 3 patch antennas as the radiating elements. The second uses stripline transmission lines, with slot antennas as the radiating sources etched into the ground plane of the triplate. Beam steering is achieved by the application of an external electromagnet. An AFSS is constructed by the interposition of PIN diodes into a dipole FSS array. Transmission response measurements are then made for various angles of electromagnetic wave incidence. Two states of operation exist: when a current is passed through the diodes and when the diodes are switched off. These two states form a high pass and band stop space filter respectively. An enclosure covered with the AFSS is constructed and externally illuminated in the range 2.0 - 2.8GHz. A probe antenna inside the enclosure positioned at various locations through out the volume is used to establish the effective screening action of the AFSS in 3 dimensional space. (author)

  3. Electrochemical activity of heavy metal oxides in the process of ...

    Indian Academy of Sciences (India)

    Unknown

    2002-02-02

    Feb 2, 2002 ... Electrochemical activity of heavy metal oxides in the process of chloride induced .... represents the protective barrier moderating the chloride attack which ... inhibitors and their influence on the physical properties of. Portland ...

  4. Evaluation of Control Parameters for the Activated Sludge Process

    Science.gov (United States)

    Stall, T. Ray; Sherrard, Josephy H.

    1978-01-01

    An evaluation of the use of the parameters currently being used to design and operate the activated sludge process is presented. The advantages and disadvantages for the use of each parameter are discussed. (MR)

  5. ACTIVATED SLUDGE PROCESS SIMULATOR ASP-SIM, PART-1 ...

    African Journals Online (AJOL)

    LUCY

    The design of activated process is usually done manually; this is often difficult and susceptible to errors ... Table 1: Typical domestic wastewater characterization parameters for CMAS design. ..... g = 9.81: molarmass = 28.97: zb = 500: za = 0: r.

  6. Highly reproducible surface-enhanced Raman scattering-active Au nanostructures prepared by simple electrodeposition: origin of surface-enhanced Raman scattering activity and applications as electrochemical substrates.

    Science.gov (United States)

    Choi, Suhee; Ahn, Miri; Kim, Jongwon

    2013-05-24

    The fabrication of effective surface-enhanced Raman scattering (SERS) substrates has been the subject of intensive research because of their useful applications. In this paper, dendritic gold (Au) rod (DAR) structures prepared by simple one-step electrodeposition in a short time were examined as an effective SERS-active substrate. The SERS activity of the DAR surfaces was compared to that of other nanostructured Au surfaces with different morphologies, and its dependence on the structural variation of DAR structures was examined. These comparisonal investigations revealed that highly faceted sharp edge sites present on the DAR surfaces play a critical role in inducing a high SERS activity. The SERS enhancement factor was estimated to be greater than 10(5), and the detection limit of rhodamine 6G at DAR surfaces was 10(-8)M. The DAR surfaces exhibit excellent spot-to-spot and substrate-to-substrate SERS enhancement reproducibility, and their long-term stability is very good. It was also demonstrated that the DAR surfaces can be effectively utilized in electrochemical SERS systems, wherein a reversible SERS behavior was obtained during the cycling to cathodic potential regions. Considering the straightforward preparation of DAR substrates and the clean nature of SERS-active Au surfaces prepared in the absence of additives, we expect that DAR surfaces can be used as cost-effective SERS substrates in analytical and electrochemical applications. Copyright © 2013 Elsevier B.V. All rights reserved.

  7. Effect of Heat Treatment on the Surface Properties of Activated Carbons

    Directory of Open Access Journals (Sweden)

    Meriem Belhachemi

    2011-01-01

    Full Text Available This work reports the effect of heat treatment on the porosity and surface chemistry of two series of activated carbons prepared from a local agricultural biomass material, date pits, by physical activation with carbon dioxide and steam. Both series samples were oxidized with nitric acid and subsequently heat treated under N2 at 973 K in order to study the effect of these treatments in porosity and surface functional groups of activated carbons. When the activated carbons were heat treated after oxidation the surface area and the pore volume increase for both activated carbons prepared by CO2 and steam activations. However the amount of surface oxygen complexes decreases, the samples keep the most stable oxygen surface groups evolved as CO by temperature-programmed desorption experiments at high temperature. The results show that date pits can be used as precursors to produce activated carbons with a well developed porosity and tailored oxygen surface groups.

  8. Surface and interface electronic structure: Sixth year activity report

    International Nuclear Information System (INIS)

    Kevan, S.D.

    1992-01-01

    Several productive runs were made on beamline U4A at NSLS. An upgrade of angle-resolved photoemission spectrometer was largely completed on the beamline. Progress was made on studies of surface states and reconstruction on Mo(001) and W(001), and of surface states and resonances on Pt(111)

  9. Drilling to investigate processes in active tectonics and magmatism

    OpenAIRE

    J. Shervais; J. Evans; V. Toy; J. Kirkpatrick; A. Clarke; J. Eichelberger

    2014-01-01

    Coordinated drilling efforts are an important method to investigate active tectonics and magmatic processes related to faults and volcanoes. The US National Science Foundation (NSF) recently sponsored a series of workshops to define the nature of future continental drilling efforts. As part of this series, we convened a workshop to explore how continental scientific drilling can be used to better understand active tectonic and magmatic processes. The workshop, held in Park C...

  10. Genetic Algorithm-Based Optimization for Surface Roughness in Cylindrically Grinding Process Using Helically Grooved Wheels

    Science.gov (United States)

    Çaydaş, Ulaş; Çelik, Mahmut

    The present work is focused on the optimization of process parameters in cylindrical surface grinding of AISI 1050 steel with grooved wheels. Response surface methodology (RSM) and genetic algorithm (GA) techniques were merged to optimize the input variable parameters of grinding. The revolution speed of workpiece, depth of cut and number of grooves on the wheel were changed to explore their experimental effects on the surface roughness of machined bars. The mathematical models were established between the input parameters and response by using RSM. Then, the developed RSM model was used as objective functions on GA to optimize the process parameters.

  11. Bioflotation of sulfide minerals with Acidithiobacillus ferrooxidans in relation to copper activation and surface oxidation.

    Science.gov (United States)

    Pecina-Treviño, E T; Ramos-Escobedo, G T; Gallegos-Acevedo, P M; López-Saucedo, F J; Orrantia-Borunda, E

    2012-09-01

    Surface oxidation of sulfides and copper (Cu) activation are 2 of the main processes that determine the efficiency of flotation. The present study was developed with the intention to ascertain the role of the phenomena in the biomodification of sulfides by Acidithiobacillus ferrooxidans culture (cells and growth media) and their impact in bioflotation. Surface characteristics of chalcopyrite, sphalerite, and pyrrhotite, alone and in mixtures, after interaction with A. ferrooxidans were evaluated. Chalcopyrite floatability was increased substantially by biomodification, while bacteria depressed pyrrhotite floatability, favoring separation. The results showed that elemental sulfur concentration increased because of the oxidation generated by bacterial cells, the effect is intensified by the Fe(III) left in the culture and by galvanic contact. Acidithiobacillus ferrooxidans culture affects the Cu activation of sphalerite. The implications of elemental sulfur concentration and Cu activation of sphalerite are key factors that must be considered for the future development of sulfide bioflotation processes, since the depressive effect of cells could be counteracted by elemental sulfur generation.

  12. Resonance Raman Optical Activity and Surface Enhanced Resonance Raman Optical Activity analysis of Cytochrome C

    DEFF Research Database (Denmark)

    Johannessen, Christian; Abdali, Salim; White, Peter C.

    2007-01-01

    High quality Resonance Raman (RR) and resonance Raman Optical Activity (ROA) spectra of cytochrome c were obtained in order to perform full assignment of spectral features of the resonance ROA spectrum. The resonance ROA spectrum of cytochrome c revealed a distinct spectral signature pattern due...... to resonance enhanced skeletal porphyrin vibrations, more pronounced than any contribution from the protein back-bone. Combining the intrinsic resonance enhancement of cytochrome c with surface plasmon enhancement by colloidal silver particles, the Surface Enhanced Resonance Raman Scattering (SERRS) and Chiral...... Enhanced Raman Spectroscopy (ChERS) spectra of the protein were successfully obtained at very low concentration (as low as 1 µM). The assignment of spectral features was based on the information obtained from the RR and resonance ROA spectra. Excellent agreement between RR and SERRS spectra is reported...

  13. The alkaline pre-filming process of the RWCU piping surface

    Energy Technology Data Exchange (ETDEWEB)

    Kao, D-Y.; Wen, T-J., E-mail: dahyukao@iner.gov.tw [Atomic Energy Council, Inst. of Nuclear Energy Research, Lungtan Taoyuan, Taiwan (China); Fong, C., E-mail: clinton@itri.org.tw [Industrial Technology Research Inst., Chutung, Hsinchu (China); Lu, J-H., E-mail: u879864@taipower.com.tw [Taiwan Power Co., Lungmen Nuclear Power Plant, Gongliao Township, Taipei County (China)

    2010-07-01

    The radiation dose rate on a BWR can cause great damage to operators and their maintenances working quality, so it is very important to lower it. The RWCU of a BWR primary system has the highest radiation dose rate and deposition of an active corrosion product because of: continually cleaning the reactor water and the repeated, acute change of temperature. The Lungmen NPP was built as an advanced BWR (ABWR) system. All new ABWRs in Japan, such as Kashiwazaki-Kariwa NPP units K6 and K7, Hamaoka NPP unit H5, and Shika NPP unit2, were given in passivation treatment in the stage of nuclear heating or flow-induced vibration (FIV) testing before each plant's initial start up. The conditions of alkaline pre-filming process include: pH, dissolve oxygen (DO) and temperature. This project had been decided by the results of earlier water loop testing. Three kinds of specimens including stainless steel AISI SS316L and carbon steel SA106 GrB, SA333 Gr6 were put into the autoclave located at a bypass system during the process of passivation treatment. The materials of these specimens have been used in RWCU piping, and during the alkaline pre-filming process they were monitored by AC impedances and electrochemical corrosion potential (ECP). Their surface analyses including SEM, EDS, ESCA and SIMS data were obtained from the initial test, and obtained every six months thereafter. From the SEM plot of first issue it was found that the specimens' surface of all three different materials presented excellent levels of oxidized pellets. They are almost completely packed, for both large and small granules, and the porosity is less than 40%. The deposition tests of cobalt ion were also completed. The material of stainless steel was nearly not affected through the passive process. However, carbon steel could reduce about 30% to 50% of deposited cobalt ion. This result follows the conclusion of Hatch Company. Based on the nominal cost of radiation protection, i.e. 10000 USD

  14. Continuous processing of polymers in repetitively pulsed atmospheric pressure discharges with moving surfaces and gas flow

    Energy Technology Data Exchange (ETDEWEB)

    Bhoj, Ananth N [Department of Chemical and Biomolecular Engineering, University of Illinois, Urbana, IL 61801 (United States); Kushner, Mark J [Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011 (United States)

    2007-11-21

    Atmospheric pressure corona discharges are industrially employed to treat large areas of commodity polymer sheets by creating new surface functional groups. The most common processes use oxygen containing discharges to affix oxygen to hydrocarbon polymers, thereby increasing their surface energy and wettability. The process is typically continuous and is carried out in a web configuration with film speeds of tens to hundreds of cm s{sup -1}. The densities and relative abundances of functional groups depend on the gas composition, gas flow rate and residence time of the polymer in the discharge zone which ultimately determine the magnitude and mole fractions of reactive fluxes to the surface. In this paper, results are discussed from a two-dimensional computational investigation of the atmospheric pressure plasma functionalization of a moving polypropylene sheet in repetitively pulsed He/O{sub 2}/H{sub 2}O discharges. O and OH typically initiate surface processing by hydrogen abstraction. These species are regenerated during every plasma pulse but are also largely consumed during the inter-pulse period. Longer-lived species such as O{sub 3} accumulate over many pulses and convect downstream with the gas flow. Optimizing the interplay between local rapid reactions, such as H abstraction which occurs dominantly in the discharge zone, and non-local slower processes, such as surface-surface reactions, may enable the customization of the relative abundance of surface functional groups.

  15. Continuous processing of polymers in repetitively pulsed atmospheric pressure discharges with moving surfaces and gas flow

    International Nuclear Information System (INIS)

    Bhoj, Ananth N; Kushner, Mark J

    2007-01-01

    Atmospheric pressure corona discharges are industrially employed to treat large areas of commodity polymer sheets by creating new surface functional groups. The most common processes use oxygen containing discharges to affix oxygen to hydrocarbon polymers, thereby increasing their surface energy and wettability. The process is typically continuous and is carried out in a web configuration with film speeds of tens to hundreds of cm s -1 . The densities and relative abundances of functional groups depend on the gas composition, gas flow rate and residence time of the polymer in the discharge zone which ultimately determine the magnitude and mole fractions of reactive fluxes to the surface. In this paper, results are discussed from a two-dimensional computational investigation of the atmospheric pressure plasma functionalization of a moving polypropylene sheet in repetitively pulsed He/O 2 /H 2 O discharges. O and OH typically initiate surface processing by hydrogen abstraction. These species are regenerated during every plasma pulse but are also largely consumed during the inter-pulse period. Longer-lived species such as O 3 accumulate over many pulses and convect downstream with the gas flow. Optimizing the interplay between local rapid reactions, such as H abstraction which occurs dominantly in the discharge zone, and non-local slower processes, such as surface-surface reactions, may enable the customization of the relative abundance of surface functional groups

  16. Analysis of WEDM Process Parameters on Surface Roughness and Kerf using Taguchi Method

    Directory of Open Access Journals (Sweden)

    Asfana Banu

    2017-12-01

    Full Text Available In obtaining the best quality of engineering parts, the quality of machined surface plays an essential role. The fatigue strength, wear resistance, and corrosion of workpiece are some of the aspects of the qualities that can be improved. This paper investigates the effect of wire electrical discharge machining (WEDM process parameters on surface roughness and kerf on stainless steel using distilled water as dielectric fluid and brass wire as tool electrode. The selected process parameters are voltage open, wire speed, wire tension, voltage gap, and off time. Empirical models using Taguchi method were developed for the estimation of surface roughness and kerf. The analysis revealed that off time has major influence on surface roughness and kerf. The optimum machining parameters for minimum surface roughness and kerf were found to be 10 V open voltage, 2.84 µs off time, 12 m/min wire speed, 6.3 N wire tension, and 54.91 V voltage gap.

  17. Specifics of adsorption and chemical processes on the surface of gamma-irradiated vanadium dioxide

    International Nuclear Information System (INIS)

    Kaurkovskaya, V.N.; Dzyubenko, L.S.; Doroshenko, V.N.; Chujko, A.A.; Shakhov, A.P.

    2006-01-01

    Effect of γ-irradiation on electrophysical properties and processes of thermal desorption of water from the surface of vanadium oxides V 2 O 3 -VO 2-δ -VO 2+δ -V 2 O 5 was investigated by derivatography and electric conductivity. Content of adsorbed water at the surface and phase composition of the surface was demonstrated to change under the action of low radiation doses. Surface electric conductivity of the irradiated samples VO 2-δ in the process of chemical reactions of adsorbed following irradiation benzoic acid and ethanol was established to be much above than in irradiated-free ones. It is presumed that metal-semiconductor phase transition at the surface of VO 2-δ during chemical reaction is intensified by irradiation [ru

  18. Modeling of flash calcination process during clay activation

    International Nuclear Information System (INIS)

    Borrajo Perez, Ruben; Gonzalez Bayon, Juan Jose; Sanchez Rodriguez, Andy A.

    2011-01-01

    Pozzolanic activity in some materials can be increased by means of different processes, among them, thermal activation is one of the most promising. The activation process, occurring at high temperatures and velocities produces a material with better characteristics. In the last few years, high reactivity pozzolan during cure's early days has been produced. Temperature is an important parameter in the activation process and as a consequence, the activation units must consider temperature variation to allow the use of different raw materials, each one of them with different characteristics. Considering the high prices of Kaolin in the market, new materials are being tested, the clayey soil, which after a sedimentation process produces a clay that has turned out to be a suitable raw material, when the kinetics of the pozzolanic reaction is considered. Additionally, other material with higher levels of kaolin are being used with good results. This paper is about the modeling of thermal, hydrodynamics and dehydroxilation processes suffering for solids particles exposed to a hot gas stream. The models employed are discussed; the velocity and temperature of particles are obtained as a function of carrier gas parameters. The calculation include the heat losses and finally the model predict the residence time needed for finish the activation process. (author)

  19. A study on pore-opening behaviors of graphite nanofibers by a chemical activation process.

    Science.gov (United States)

    Kim, Byung-Joo; Lee, Young-Seak; Park, Soo-Jin

    2007-02-15

    In this work, porous graphite nanofibers (GNFs) were prepared by a KOH activation method in order to manufacture porous carbon nanofibers. The process was conducted in the activation temperature range of 900-1100 degrees C, and the KOH:GNFs ratio was fixed at 3.5:1. The textural properties of the porous carbons were analyzed using N2 adsorption isotherms at 77 K. The BET, D-R, and BJH equations were used to observe the specific surface areas and the micro- and mesopore structures, respectively. From the results, it was found that the textural properties, including the specific surface area and the pore volumes, were proportionally enhanced with increasing activation temperatures. However, the activation mechanisms showed quite significant differences between the samples activated at low and high temperatures.

  20. Quality control of the documentation process in electronic economic activities

    Directory of Open Access Journals (Sweden)

    Krutova A.S.

    2017-06-01

    Full Text Available It is proved that the main tool that will provide adequate information resources e economic activities of social and economic relations are documenting quality control processes as the basis of global information space. Directions problems as formation evaluation information resources in the process of documentation, namely development tools assess the efficiency of the system components – qualitative assessment; development of mathematical modeling tools – quantitative evaluation. A qualitative assessment of electronic documentation of economic activity through exercise performance, efficiency of communication; document management efficiency; effectiveness of flow control operations; relationship management effectiveness. The concept of quality control process documents electronically economic activity to components which include: the level of workflow; forms adequacy of information; consumer quality documents; quality attributes; type of income data; condition monitoring systems; organizational level process documentation; attributes of quality, performance quality consumer; type of management system; type of income data; condition monitoring systems. Grounded components of the control system electronic document subjects of economic activity. Detected components IT-audit management system economic activity: compliance audit; audit of internal control; detailed multilevel analysis; corporate risk assessment methodology. The stages and methods of processing electronic transactions economic activity during condition monitoring of electronic economic activity.

  1. Processing of Building Binder Materials to Increase their Activation

    Science.gov (United States)

    Fediuk, R. S.; Garmashov, I. S.; Kuzmin, D. E.; Stoyushko, N. Yu; Gladkova, N. A.

    2018-01-01

    The paper deals modern physical methods of activation of building powder materials. During mechanical activation a composite binder active molecules cement minerals occur in the destruction of the molecular defects in the areas of packaging and breaking metastable phase decompensation intermolecular forces. The process is accompanied by a change in the kinetics of hardening of Portland cement. Activated concrete has a number of features that are used as design characteristics of structures and are due to the structure of the activated binder and its contacts with concrete aggregates. These features also have a significant impact on the nature of the destruction of concrete under load, changing the boundaries of its microcracks and durability.

  2. Effect of conditioner load on the polishing pad surface during chemical mechanical planarization process

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Cheol Min; Qin, Hong Yi; Hong, Seok Jun; Jeon, Sang Hyuk; Kulkarni, Atul; Kim, Tae Sun [Sungkyunkwan University, Suwon (Korea, Republic of)

    2016-12-15

    During the Chemical mechanical planarization (CMP), the pad conditioning process can affect the pad surface characteristics. Among many CMP process parameters, the improper applied load on the conditioner arm may have adverse effects on the polyurethane pad. In this work, we evaluated the pad surface properties under the various conditioner arm applied during pad conditioning process. The conditioning pads were evaluated for surface topography, surface roughness parameters such as Rt and Rvk and Material removal rate (MRR) and within-wafer non-uniformity after wafer polishing. We observed that, the pad asperities were collapsed in the direction of conditioner rotation and blocks the pad pores applied conditioner load. The Rvk value and MRR were founded to be in relation with 4 > 1 > 7 kgF conditioner load. Hence, this study shows that, 4 kgF applied load by conditioner is most suitable for the pad conditioning during CMP.

  3. Formal Verification of Effectiveness of Control Activities in Business Processes

    Science.gov (United States)

    Arimoto, Yasuhito; Iida, Shusaku; Futatsugi, Kokichi

    It has been an important issue to deal with risks in business processes for achieving companies' goals. This paper introduces a method for applying a formal method to analysis of risks and control activities in business processes in order to evaluate control activities consistently, exhaustively, and to give us potential to have scientific discussion on the result of the evaluation. We focus on document flows in business activities and control activities and risks related to documents because documents play important roles in business. In our method, document flows including control activities are modeled and it is verified by OTS/CafeOBJ Method that risks about falsification of documents are avoided by control activities in the model. The verification is done by interaction between humans and CafeOBJ system with theorem proving, and it raises potential to discuss the result scientifically because the interaction gives us rigorous reasons why the result is derived from the verification.

  4. Process for encapsulating active agents obtaining a gel

    NARCIS (Netherlands)

    Yilmaz, G.; Jongboom, R.O.J.

    2001-01-01

    The present invention relates to a process for encapsulating an active agent in a biopolymer in the form of a gel, comprising the steps of: a) forming a dispersion or solution of the biopolymer in water; and b) adding the active agent to the dispersion or solution obtained in step a); wherein the

  5. Students’ learning activities while studying biological process diagrams

    NARCIS (Netherlands)

    Kragten, M.; Admiraal, W.; Rijlaarsdam, G.

    2015-01-01

    Process diagrams describe how a system functions (e.g. photosynthesis) and are an important type of representation in Biology education. In the present study, we examined students’ learning activities while studying process diagrams, related to their resulting comprehension of these diagrams. Each

  6. Instructional Transaction Theory: Knowledge Relationships among Processes, Entities, and Activities.

    Science.gov (United States)

    Merrill, M. David; And Others

    1993-01-01

    Discussion of instructional transaction theory focuses on knowledge representation in an automated instructional design expert system. A knowledge structure called PEA-Net (processes, entities, and activities) is explained; the refrigeration process is used as an example; text resources and graphic resources are described; and simulations are…

  7. Improvement of silicon direct bonding using surfaces activated by hydrogen plasma treatment

    CERN Document Server

    Choi, W B; Lee Jae Sik; Sung, M Y

    2000-01-01

    The plasma surface treatment, using hydrogen gas, of silicon wafers was studied as a pretreatment for silicon direct bonding. Chemical reactions of the hydrogen plasma with the surfaces were used for both surface activation and removal of surface contaminants. Exposure of the silicon wafers to the plasma formed an active oxide layer on the surface. This layer was hydrophilic. The surface roughness and morphology were examined as functions of the plasma exposure time and power. The surface became smoother with shorter plasma exposure time and lower power. In addition, the plasma surface treatment was very efficient in removing the carbon contaminants on the silicon surface. The value of the initial surface energy, as estimated by using the crack propagation method, was 506 mJ/M sup 2 , which was up to about three times higher than the value for the conventional direct bonding method using wet chemical treatments.

  8. Cascading activation from lexical processing to letter-level processing in written word production.

    Science.gov (United States)

    Buchwald, Adam; Falconer, Carolyn

    2014-01-01

    Descriptions of language production have identified processes involved in producing language and the presence and type of interaction among those processes. In the case of spoken language production, consensus has emerged that there is interaction among lexical selection processes and phoneme-level processing. This issue has received less attention in written language production. In this paper, we present a novel analysis of the writing-to-dictation performance of an individual with acquired dysgraphia revealing cascading activation from lexical processing to letter-level processing. The individual produced frequent lexical-semantic errors (e.g., chipmunk → SQUIRREL) as well as letter errors (e.g., inhibit → INBHITI) and had a profile consistent with impairment affecting both lexical processing and letter-level processing. The presence of cascading activation is suggested by lower letter accuracy on words that are more weakly activated during lexical selection than on those that are more strongly activated. We operationalize weakly activated lexemes as those lexemes that are produced as lexical-semantic errors (e.g., lethal in deadly → LETAHL) compared to strongly activated lexemes where the intended target word (e.g., lethal) is the lexeme selected for production.

  9. Surface preparation process of a uranium titanium alloy, in particular for chemical nickel plating

    International Nuclear Information System (INIS)

    Henri, A.; Lefevre, D.; Massicot, P.

    1987-01-01

    In this process the uranium alloy surface is attacked with a solution of lithium chloride and hydrochloric acid. Dissolved uranium can be recovered from the solution by an ion exchange resin. Treated alloy can be nickel plated by a chemical process [fr

  10. Surface modification on a glass surface with a combination technique of sol–gel and air brushing processes

    KAUST Repository

    Tsai, Meng-Yu; Hsu, Chin-Chi; Chen, Ping-Hei; Lin, Chao-Sung; Chen, Alexander

    2011-01-01

    This study fabricated the large area and optically transparent superhydrophobic silica based films on glass surface with optimized hardness. A silane coupling agent, tetraethoxysilane (TEOS), effectively bonds silica particles onto the glass substrate. Desired surface roughness was obtained by adjusting nano silica particles concentration of the precursors prepared by the sol-gel process. Silica suspension was coated onto the glass substrate by the air brushing methods. This method can deposit a uniform, transparent coating on the glass substrate efficiently. Diluting the precursor by adding ethanol or a mixture of D.I. water and ethanol further improved the transmittance and superhydrophobicity efficiency. The results showed that as the silica particle concentration and the thickness of the coating were increased, the surface roughness was enhanced. Rougher surface displayed a higher superhydrophobicity and lower transmittance. Therefore, the concentration of silica particle, volume of coatings, and the ratio of ethanol and D.I. water are of great importance to deposit a transparent, superhydrophobic coating on glass. © 2011 Elsevier B.V. All rights reserved.

  11. Surface modification on a glass surface with a combination technique of sol–gel and air brushing processes

    KAUST Repository

    Tsai, Meng-Yu

    2011-08-01

    This study fabricated the large area and optically transparent superhydrophobic silica based films on glass surface with optimized hardness. A silane coupling agent, tetraethoxysilane (TEOS), effectively bonds silica particles onto the glass substrate. Desired surface roughness was obtained by adjusting nano silica particles concentration of the precursors prepared by the sol-gel process. Silica suspension was coated onto the glass substrate by the air brushing methods. This method can deposit a uniform, transparent coating on the glass substrate efficiently. Diluting the precursor by adding ethanol or a mixture of D.I. water and ethanol further improved the transmittance and superhydrophobicity efficiency. The results showed that as the silica particle concentration and the thickness of the coating were increased, the surface roughness was enhanced. Rougher surface displayed a higher superhydrophobicity and lower transmittance. Therefore, the concentration of silica particle, volume of coatings, and the ratio of ethanol and D.I. water are of great importance to deposit a transparent, superhydrophobic coating on glass. © 2011 Elsevier B.V. All rights reserved.

  12. Topological characterization of antireflective and hydrophobic rough surfaces: are random process theory and fractal modeling applicable?

    Science.gov (United States)

    Borri, Claudia; Paggi, Marco

    2015-02-01

    The random process theory (RPT) has been widely applied to predict the joint probability distribution functions (PDFs) of asperity heights and curvatures of rough surfaces. A check of the predictions of RPT against the actual statistics of numerically generated random fractal surfaces and of real rough surfaces has been only partially undertaken. The present experimental and numerical study provides a deep critical comparison on this matter, providing some insight into the capabilities and limitations in applying RPT and fractal modeling to antireflective and hydrophobic rough surfaces, two important types of textured surfaces. A multi-resolution experimental campaign using a confocal profilometer with different lenses is carried out and a comprehensive software for the statistical description of rough surfaces is developed. It is found that the topology of the analyzed textured surfaces cannot be fully described according to RPT and fractal modeling. The following complexities emerge: (i) the presence of cut-offs or bi-fractality in the power-law power-spectral density (PSD) functions; (ii) a more pronounced shift of the PSD by changing resolution as compared to what was expected from fractal modeling; (iii) inaccuracy of the RPT in describing the joint PDFs of asperity heights and curvatures of textured surfaces; (iv) lack of resolution-invariance of joint PDFs of textured surfaces in case of special surface treatments, not accounted for by fractal modeling.

  13. Surface activation of MnNb{sub 2}O{sub 6} nanosheets by oxalic acid for enhanced photocatalysis

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Junshu; Wang, Jinshu, E-mail: wangjsh@bjut.edu.cn; Li, Hongyi; Li, Yongli; Du, Yucheng; Yang, Yilong; Jia, Xinjian

    2017-05-01

    Graphical abstract: Visible light driven photoreduction of Cr(VI) over MnNb{sub 2}O{sub 6} nanosheets is enhanced via oxalic acid surface complex to generate activation layer. - Highlights: • MnNb{sub 2}O{sub 6} nanosheets are crystallized by a surface capping route of sulfonate groups. • Oxalic acid on MnNb{sub 2}O{sub 6} nanosheets forms an excited surface complex hybrid layer. • Surface activation enhances visible-light induced reduction of Cr(VI) into Cr(III). - Abstract: MnNb{sub 2}O{sub 6} nanosheets (P-MNOs) is selectively crystallized by using surface capping ligand with functional sulfonate group (sodium dodecyl benzene sulphonate), which binds to the (131) surface of MnNb{sub 2}O{sub 6} inducing the morphology-controlled crystallization of MnNb{sub 2}O{sub 6} materials. Surface modification of photoactive P-MNOs with electron-rich oxalic acid ligands establishes an excited surface complex layer on phase-pure P-MNO as evidenced by spectroscopic analyses (FT-IR, UV–vis, Raman, PL, etc.), and thus more efficiently photocatalyzes the reduction of Cr(VI) into Cr(III) than solely P-MNOs or oxalic acid under visible light (λ > 420 nm) via a ligand-to-metal interfacial electron transfer pathway. However, the interaction between oxalic acid and MnNb{sub 2}O{sub 6} is highly dependent upon the morphology of solid MnNb{sub 2}O{sub 6} substrate due to the higher surface-area-to-volume ratio and higher surface activity of (131) planes in the sheet-like morphology. This study could assist the construction of stable niobate material systems to allow a versatile solid surface activation for establishing more energy efficient and robust catalysis process under visible light.

  14. Effects of Micromachining Processes on Electro-Osmotic Flow Mobility of Glass Surfaces

    Directory of Open Access Journals (Sweden)

    Norihisa Miki

    2013-03-01

    Full Text Available Silica glass is frequently used as a device material for micro/nano fluidic devices due to its excellent properties, such as transparency and chemical resistance. Wet etching by hydrofluoric acid and dry etching by neutral loop discharge (NLD plasma etching are currently used to micromachine glass to form micro/nano fluidic channels. Electro-osmotic flow (EOF is one of the most effective methods to drive liquids into the channels. EOF mobility is affected by a property of the micromachined glass surfaces, which includes surface roughness that is determined by the manufacturing processes. In this paper, we investigate the effect of micromaching processes on the glass surface topography and the EOF mobility. We prepared glass surfaces by either wet etching or by NLD plasma etching, investigated the surface topography using atomic force microscopy, and attempted to correlate it with EOF generated in the micro-channels of the machined glass. Experiments revealed that the EOF mobility strongly depends on the surface roughness, and therefore upon the fabrication process used. A particularly strong dependency was observed when the surface roughness was on the order of the electric double layer thickness or below. We believe that the correlation described in this paper can be of great help in the design of micro/nano fluidic devices.

  15. Sensing surface mechanical deformation using active probes driven by motor proteins

    Science.gov (United States)

    Inoue, Daisuke; Nitta, Takahiro; Kabir, Arif Md. Rashedul; Sada, Kazuki; Gong, Jian Ping; Konagaya, Akihiko; Kakugo, Akira

    2016-01-01

    Studying mechanical deformation at the surface of soft materials has been challenging due to the difficulty in separating surface deformation from the bulk elasticity of the materials. Here, we introduce a new approach for studying the surface mechanical deformation of a soft material by utilizing a large number of self-propelled microprobes driven by motor proteins on the surface of the material. Information about the surface mechanical deformation of the soft material is obtained through changes in mobility of the microprobes wandering across the surface of the soft material. The active microprobes respond to mechanical deformation of the surface and readily change their velocity and direction depending on the extent and mode of surface deformation. This highly parallel and reliable method of sensing mechanical deformation at the surface of soft materials is expected to find applications that explore surface mechanics of soft materials and consequently would greatly benefit the surface science. PMID:27694937

  16. Effect of processing parameters of rotary ultrasonic machining on surface integrity of potassium dihydrogen phosphate crystals

    Directory of Open Access Journals (Sweden)

    Jianfu Zhang

    2015-09-01

    Full Text Available Potassium dihydrogen phosphate is an important optical crystal. However, high-precision processing of large potassium dihydrogen phosphate crystal workpieces is difficult. In this article, surface roughness and subsurface damage characteristics of a (001 potassium dihydrogen phosphate crystal surface produced by traditional and rotary ultrasonic machining are studied. The influence of process parameters, including spindle speed, feed speed, type and size of sintered diamond wheel, ultrasonic power, and selection of cutting fluid on potassium dihydrogen phosphate crystal surface integrity, was analyzed. The surface integrity, especially the subsurface damage depth, was affected significantly by the ultrasonic power. Metal-sintered diamond tools with high granularity were most suitable for machining potassium dihydrogen phosphate crystal. Cutting fluid played a key role in potassium dihydrogen phosphate crystal machining. A more precise surface can be obtained in machining with a higher spindle speed, lower feed speed, and using kerosene as cutting fluid. Based on the provided optimized process parameters for machining potassium dihydrogen phosphate crystal, a processed surface quality with Ra value of 33 nm and subsurface damage depth value of 6.38 μm was achieved.

  17. Optimization of CO2 Laser Cutting Process using Taguchi and Dual Response Surface Methodology

    Directory of Open Access Journals (Sweden)

    M. Madić

    2014-09-01

    Full Text Available Selection of optimal cutting parameter settings for obtaining high cut quality in CO2 laser cutting process is of great importance. Among various analytical and experimental optimization methods, the application of Taguchi and response surface methodology is one of most commonly used for laser cutting process optimization. Although the concept of dual response surface methodology for process optimization has been used with success, till date, no experimental study has been reported in the field of laser cutting. In this paper an approach for optimization of CO2 laser cutting process using Taguchi and dual response surface methodology is presented. The goal was to determine the near optimal laser cutting parameter values in order to ensure robust condition for minimization of average surface roughness. To obtain experimental database for development of response surface models, Taguchi’s L25 orthogonal array was implemented for experimental plan. Three cutting parameters, the cutting speed (3, 4, 5, 6, 7 m/min, the laser power (0.7, 0.9, 1.1, 1.3, 1.5 kW, and the assist gas pressure (3, 4, 5, 6, 7 bar, were used in the experiment. To obtain near optimal cutting parameters settings, multi-stage Monte Carlo simulation procedure was performed on the developed response surface models.

  18. Martian aeolian activity at the Bagnold Dunes, Gale Crater: The view from the surface and orbit

    Science.gov (United States)

    Bridges, N. T.; Sullivan, R.; Newman, C. E.; Navarro, S.; van Beek, J.; Ewing, R. C.; Ayoub, F.; Silvestro, S.; Gasnault, O.; Le Mouélic, S.; Lapotre, M. G. A.; Rapin, W.

    2017-10-01

    The first in situ investigation of an active dune field on another planetary surface occurred in 2015-2016 when the Mars Science Laboratory Curiosity rover investigated the Bagnold Dunes on Mars. High Resolution Imaging Science Experiment images show clear seasonal variations that are in good agreement with atmospheric model predictions of intra-annual sand flux and migration directions that together indicate that the campaign occurred during a period of low wind activity. Curiosity surface images show that limited changes nevertheless occurred, with movement of large grains, particularly on freshly exposed surfaces, two occurrences of secondary grain flow on the slip face of Namib Dune, and a slump on a freshly exposed surface of a large ripple. These changes are seen at Martian solar day (sol)-to-sol time scales. Grains on a rippled sand deposit and unconsolidated dump piles show limited movement of large grains over a few hours during which mean friction speeds are estimated at 0.3-0.4 m s-1. Overall, the correlation between changes and peak Rover Environmental Monitoring Station (REMS) winds is moderate, with high wind events associated with changes in some cases, but not in others, suggesting that other factors are also at work. The distribution of REMS 1 Hz wind speeds shows a significant tail up to the current 20 m s-1 calibration limit, indicating that even higher speed winds occur. Nonaeolian triggering mechanisms are also possible. The low activity period at the dunes documented by Curiosity provides clues to processes that dominated in the Martian past under conditions of lower obliquity.

  19. Effect of enzymatic treatment of extracted sunflower proteins on solubility, amino acid composition, and surface activity.

    Science.gov (United States)

    Conde, José Miñones; Escobar, María del Mar Yust; Pedroche Jiménez, Justo J; Rodríguez, Francisco Millán; Rodríguez Patino, Juan M

    2005-10-05

    Industrial proteins from agriculture of either animal or vegetable origin, including their peptide derivatives, are of great importance, from the qualitative and quantitative point of view, in food formulations (emulsions and foams). A fundamental understanding of the physical, chemical, and functional properties of these proteins is essential if the performance of proteins in foods is to be improved and if underutilized proteins, such as plant proteins (and their hydrolysates and peptides derivatives), are to be increasingly used in traditional and new processed food products (safe, high-quality, health foods with good nutritional value). In this contribution we have determined the main physicochemical characteristics (solubility, composition, and analysis of amino acids) of a sunflower protein isolate (SPI) and its hydrolysates with low (5.62%), medium (23.5%), and high (46.3%) degrees of hydrolysis. The hydrolysates were obtained by enzymatic treatment with Alcalase 2.4 L for DH 5.62 and 23.5% and with Alcalase 2.4 L and Flavorzyme 1000 MG sequentially for DH 46.3%. The protein concentration dependence on surface pressure (surface pressure isotherm), a measure of the surface activity of the products (SPI and its hydrolysates), was obtained by tensiometry. We have observed that the degree of hydrolysis has an effect on solubility, composition, and content of the amino acids of the SPI and its hydrolysates. The superficial activity and the adsorption efficiency were also affected by the degree of hydrolysis.

  20. Synthesis and processing of ELISA polymer substitute: The influence of surface chemistry and morphology on detection sensitivity

    Science.gov (United States)

    Hosseini, Samira; Ibrahim, Fatimah; Djordjevic, Ivan; Rothan, Hussin A.; Yusof, Rohana; van der Marel, Cees; Koole, Leo H.

    2014-10-01

    Despite the known drawbacks of enzyme-linked immunosorbent assay (ELISA), one of the deficiencies that have relatively been ignored is the performance of ELISA substrate itself. Polystyrene (PS), as the cost effective material of choice for mass production of ELISA well-plates, has shown obvious lacks of suitable physical and chemical properties for protein attachment. The general concept of this work was to develop a potential substrate that can be suggested as a material of choice for production of a new generation of ELISA analytical kits. Spin-coated thin films of polymethyl methacrylate-co-methacrylic acid (PMMA-co-MAA) on silicon surfaces were designed and processed for detection of dengue virus. Coated surfaces of different molar ratios have been investigated as carboxyl-functionalized layers for obtaining platform for biomolecule immobilization with high level of protein activity. To improve the sensitivity of detection, we have used amine functional "spacers", hexamethylenediamine (HMDA) and polyethyleneimine (PEI), which were covalently bonded to the surfaces of PMMA-co-MAA coatings. Results demonstrate that the variation of surface concentration of carboxyl groups of PMMA-co-MAA can be used to control the amine surface concentration after carbodiimide coupling with HMDA and PEI spacers. The presence of amine spacers increases hydrophilicity of the coatings and significantly impacts the polymer surface morphology. In particular, protein immobilization via amine-bearing spacers has been achieved in two effective steps: (1) carbodiimide bonding between amine spacer molecules and PMMA-co-MAA polymer coatings; and (2) covalent immobilization of antibody via glutaraldehyde reaction with amine groups from amine-treated surfaces. The application of PEI spacer in comparison to HMDA has shown much higher intensity of detection signal in ELISA experiment, indicating better immobilization efficiency and preservation of antibody activity upon attachment to the

  1. APPLICABILITY OF ACTIVITY BASED COSTING IN NEW PRODUCT DEVELOPMENT PROCESSES

    Directory of Open Access Journals (Sweden)

    Ewa Wanda MARUSZEWSKA

    2015-01-01

    Full Text Available The purpose of the article is to emphasis that activity based costing is a proper tool for engineers to enhance their deci-sion-making process while developing new product. The theoretical analysis shows that variety of factors shall be en-compassed into new product decision-making process and therefore engineers and management should pay great attention to proper cost allocation. The paper suggests the usage of Activity Based Costing methodology for new product development decision-making process. Author states that application ABC in the process of rational decision-making referring to new product development enables managers and engineers to prioritize possible solutions, and reallocate resources used in production process in order to meet wider organizational goals. It would also contribute in coopera-tion of managers and engineers for the sake of organizational goal.

  2. Process benchmarking for improvement of environmental restoration activities

    International Nuclear Information System (INIS)

    Celorie, J.A.; Selman, J.R.; Larson, N.B.

    1995-01-01

    A process benchmarking study was initiated by the Office of Environmental Management (EM) of the US Department of Energy (DOE) to analyze and improve the department's environmental assessment and environmental restoration (ER) processes. The purpose of this study was to identify specific differences in the processes and implementation procedures used at comparable remediation sites to determine best practices which had the greatest potential to minimize the cost and time required to conduct remedial investigation/ feasibility study (RI/FS) activities. Technical criteria were identified and used to select four DOE, two Department of Defense (DOD), and two Environmental Protection Agency (EPA) restoration sites that exhibited comparable characteristics and regulatory environments. By comparing the process elements and activities executed at the different sites for similar endpoints, best practices were identified for streamlining process elements and minimizing non-value-added activities. Critical measures that influenced process performance were identified and characterized for the sites. This benchmarking study focused on two processes and the internal/external review of documents and the development of the initial evaluation and data collection plan (IEDCP)--since these had a great potential for savings, a high impact on other processes, and a high probability for implementation

  3. Process comparison for fracture-induced formation of surface structures on polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yueh-Ying [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Yang, Fuqian [Department of Chemical and Materials Engineering, University of Kentucky, Lexington, KY 40506 (United States); Chen, Chia-Chieh [Institute of Nuclear Energy Research, Longtan, Taoyuan 32546, Taiwan (China); Lee, Sanboh, E-mail: sblee@mx.nthu.edu.tw [Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan (China)

    2014-01-01

    Using three different splitting approaches such as point-load splitting, tension-splitting and peeling–splitting, different surface ripples were produced on poly(methyl methacrylate) (PMMA)-based polymer films. Independent of the splitting approaches, the spatial wavelength of the surface structures is a linear function of the film thickness with the approximately same differential ratio of the spatial wavelength to the film thickness. The apparent surface residual stress was calculated from the thickness dependence of the spatial frequency, and the magnitude of the apparent surface stress increased with the increase of the film thickness. After exposing the aged PMMA-based photoresist at liquid state to gamma-irradiation, the effects of aging and the gamma-irradiation were investigated on the splitting-induced formation of surface structures. For the peeling–splitting process, the differential ratio of the spatial wavelength to the film thickness for the aged samples is larger than that for non-aged samples. The point-load splitting could not produce any surface pattern on the gamma-irradiated films. None of the splitting approaches could form surface structures for polymer films exposed to irradiation of high dose. Both the spatial wavelength and the apparent surface stress increased with the film thickness for the irradiated polymer films. - Highlights: • Using splitting processes, surface ripples were formed on polymer films. • The surface ripples were induced by compressively apparent surface stress. • The spatial wavelength of the ripples is a linear function of the film thickness. • The spatial wavelength of the ripples is affected by gamma-ray irradiation. • The spatial wavelength of the ripples is affected by aging.

  4. Distribution and Characteristics of Boulder Halos at High Latitudes on Mars: Ground Ice and Surface Processes Drive Surface Reworking

    Science.gov (United States)

    Levy, J. S.; Fassett, C. I.; Rader, L. X.; King, I. R.; Chaffey, P. M.; Wagoner, C. M.; Hanlon, A. E.; Watters, J. L.; Kreslavsky, M. A.; Holt, J. W.; Russell, A. T.; Dyar, M. D.

    2018-02-01

    Boulder halos are circular arrangements of clasts present at Martian middle to high latitudes. Boulder halos are thought to result from impacts into a boulder-poor surficial unit that is rich in ground ice and/or sediments and that is underlain by a competent substrate. In this model, boulders are excavated by impacts and remain at the surface as the crater degrades. To determine the distribution of boulder halos and to evaluate mechanisms for their formation, we searched for boulder halos over 4,188 High Resolution Imaging Science Experiment images located between 50-80° north and 50-80° south latitude. We evaluate geological and climatological parameters at halo sites. Boulder halos are about three times more common in the northern hemisphere than in the southern hemisphere (19% versus 6% of images) and have size-frequency distributions suggesting recent Amazonian formation (tens to hundreds of millions of years). In the north, boulder halo sites are characterized by abundant shallow subsurface ice and high thermal inertia. Spatial patterns of halo distribution indicate that excavation of boulders from beneath nonboulder-bearing substrates is necessary for the formation of boulder halos, but that alone is not sufficient. Rather, surface processes either promote boulder halo preservation in the north or destroy boulder halos in the south. Notably, boulder halos predate the most recent period of near-surface ice emplacement on Mars and persist at the surface atop mobile regolith. The lifetime of observed boulders at the Martian surface is greater than the lifetime of the craters that excavated them. Finally, larger minimum boulder halo sizes in the north indicate thicker icy soil layers on average throughout climate variations driven by spin/orbit changes during the last tens to hundreds of millions of years.

  5. Surface regions of illusory images are detected with a slower processing speed than those of luminance-defined images.

    Science.gov (United States)

    Mihaylova, Milena; Manahilov, Velitchko

    2010-11-24

    Research has shown that the processing time for discriminating illusory contours is longer than for real contours. We know, however, little whether the visual processes, associated with detecting regions of illusory surfaces, are also slower as those responsible for detecting luminance-defined images. Using a speed-accuracy trade-off (SAT) procedure, we measured accuracy as a function of processing time for detecting illusory Kanizsa-type and luminance-defined squares embedded in 2D static luminance noise. The data revealed that the illusory images were detected at slower processing speed than the real images, while the points in time, when accuracy departed from chance, were not significantly different for both stimuli. The classification images for detecting illusory and real squares showed that observers employed similar detection strategies using surface regions of the real and illusory squares. The lack of significant differences between the x-intercepts of the SAT functions for illusory and luminance-modulated stimuli suggests that the detection of surface regions of both images could be based on activation of a single mechanism (the dorsal magnocellular visual pathway). The slower speed for detecting illusory images as compared to luminance-defined images could be attributed to slower processes of filling-in of regions of illusory images within the dorsal pathway.

  6. Synthesis and processing of ELISA polymer substitute: The influence of surface chemistry and morphology on detection sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Hosseini, Samira; Ibrahim, Fatimah [Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Center for Innovation in Medical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Djordjevic, Ivan, E-mail: ivan.djordjevic@um.edu.my [Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Center for Innovation in Medical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Rothan, Hussin A.; Yusof, Rohana [Department of Molecular Medicine, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur (Malaysia); Marel, Cees van der [Philips Materials Analysis, High Tech Campus 11, 5656 AE Eindhoven (Netherlands); Koole, Leo H. [Department of Biomedical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Center for Innovation in Medical Engineering, Faculty of Engineering, University of Malaya, Kuala Lumpur 50603 (Malaysia); Faculty of Health, Medicine and Life Sciences, Maastricht University (Netherlands)

    2014-10-30

    Highlights: • Polyacrylate coatings with controlled surface functionalities. • Impact of surface chemistry and morphology on dengue antibody immobilization. • Enhancement of detection signal as a result of bio-activation of polymer surface. - Abstract: Despite the known drawbacks of enzyme-linked immunosorbent assay (ELISA), one of the deficiencies that have relatively been ignored is the performance of ELISA substrate itself. Polystyrene (PS), as the cost effective material of choice for mass production of ELISA well-plates, has shown obvious lacks of suitable physical and chemical properties for protein attachment. The general concept of this work was to develop a potential substrate that can be suggested as a material of choice for production of a new generation of ELISA analytical kits. Spin-coated thin films of polymethyl methacrylate-co-methacrylic acid (PMMA-co-MAA) on silicon surfaces were designed and processed for detection of dengue virus. Coated surfaces of different molar ratios have been investigated as carboxyl-functionalized layers for obtaining platform for biomolecule immobilization with high level of protein activity. To improve the sensitivity of detection, we have used amine functional “spacers”, hexamethylenediamine (HMDA) and polyethyleneimine (PEI), which were covalently bonded to the surfaces of PMMA-co-MAA coatings. Results demonstrate that the variation of surface concentration of carboxyl groups of PMMA-co-MAA can be used to control the amine surface concentration after carbodiimide coupling with HMDA and PEI spacers. The presence of amine spacers increases hydrophilicity of the coatings and significantly impacts the polymer surface morphology. In particular, protein immobilization via amine-bearing spacers has been achieved in two effective steps: (1) carbodiimide bonding between amine spacer molecules and PMMA-co-MAA polymer coatings; and (2) covalent immobilization of antibody via glutaraldehyde reaction with amine groups

  7. Synthesis and processing of ELISA polymer substitute: The influence of surface chemistry and morphology on detection sensitivity

    International Nuclear Information System (INIS)

    Hosseini, Samira; Ibrahim, Fatimah; Djordjevic, Ivan; Rothan, Hussin A.; Yusof, Rohana; Marel, Cees van der; Koole, Leo H.

    2014-01-01

    Highlights: • Polyacrylate coatings with controlled surface functionalities. • Impact of surface chemistry and morphology on dengue antibody immobilization. • Enhancement of detection signal as a result of bio-activation of polymer surface. - Abstract: Despite the known drawbacks of enzyme-linked immunosorbent assay (ELISA), one of the deficiencies that have relatively been ignored is the performance of ELISA substrate itself. Polystyrene (PS), as the cost effective material of choice for mass production of ELISA well-plates, has shown obvious lacks of suitable physical and chemical properties for protein attachment. The general concept of this work was to develop a potential substrate that can be suggested as a material of choice for production of a new generation of ELISA analytical kits. Spin-coated thin films of polymethyl methacrylate-co-methacrylic acid (PMMA-co-MAA) on silicon surfaces were designed and processed for detection of dengue virus. Coated surfaces of different molar ratios have been investigated as carboxyl-functionalized layers for obtaining platform for biomolecule immobilization with high level of protein activity. To improve the sensitivity of detection, we have used amine functional “spacers”, hexamethylenediamine (HMDA) and polyethyleneimine (PEI), which were covalently bonded to the surfaces of PMMA-co-MAA coatings. Results demonstrate that the variation of surface concentration of carboxyl groups of PMMA-co-MAA can be used to control the amine surface concentration after carbodiimide coupling with HMDA and PEI spacers. The presence of amine spacers increases hydrophilicity of the coatings and significantly impacts the polymer surface morphology. In particular, protein immobilization via amine-bearing spacers has been achieved in two effective steps: (1) carbodiimide bonding between amine spacer molecules and PMMA-co-MAA polymer coatings; and (2) covalent immobilization of antibody via glutaraldehyde reaction with amine groups

  8. Influence of activated carbon characteristics on toluene and hexane adsorption: Application of surface response methodology

    Science.gov (United States)

    Izquierdo, Mª Teresa; de Yuso, Alicia Martínez; Valenciano, Raquel; Rubio, Begoña; Pino, Mª Rosa

    2013-01-01

    The objective of this study was to evaluate the adsorption capacity of toluene and hexane over activated carbons prepared according an experimental design, considering as variables the activation temperature, the impregnation ratio and the activation time. The response surface methodology was applied to optimize the adsorption capacity of the carbons regarding the preparation conditions that determine the physicochemical characteristics of the activated carbons. The methodology of preparation produced activated carbons with surface areas and micropore volumes as high as 1128 m2/g and 0.52 cm3/g, respectively. Moreover, the activated carbons exhibit mesoporosity, ranging from 64.6% to 89.1% the percentage of microporosity. The surface chemistry was characterized by TPD, FTIR and acid-base titration obtaining different values of surface groups from the different techniques because the limitation of each technique, but obtaining similar trends for the activated carbons studied. The exhaustive characterization of the activated carbons allows to state that the measured surface area does not explain the adsorption capacity for either toluene or n-hexane. On the other hand, the surface chemistry does not explain the adsorption results either. A compromise between physical and chemical characteristics can be obtained from the appropriate activation conditions, and the response surface methodology gives the optimal activated carbon to maximize adsorption capacity. Low activation temperature, intermediate impregnation ratio lead to high toluene and n-hexane adsorption capacities depending on the activation time, which a determining factor to maximize toluene adsorption.

  9. Fabrication of SERS Active Surface on Polyimide Sample by Excimer Laser Irradiation

    Directory of Open Access Journals (Sweden)

    T. Csizmadia

    2014-01-01

    Full Text Available A possible application of excimer laser irradiation for the preparation of surface enhanced Raman spectroscopy (SERS substrate is demonstrated. A polyimide foil of 125 μm thickness was irradiated by 240 pulses of focused ArF excimer laser beam (λ = 193 nm, FWHM = 20 ns. The applied fluence was varied between 40 and 80 mJ/cm2. After laser processing, the sample was coated with 40 nm silver by PLD in order to create a conducting layer required for the SERS application. The SERS activity of the samples was tested by Raman microscopy. The Raman spectra of Rhodamine 6G aqueous solution (c=10−3 mol/dm3 were collected from the patterned and metalized areas. For areas prepared at 40–60 mJ/cm2 laser fluences, the measured Raman intensities have shown a linear dependence on the applied laser fluence, while above 60 mJ/cm2 saturation was observed. The morphology of the SERS active surface areas was investigated by scanning electron microscopy. Finite element modeling was performed in order to simulate the laser-absorption induced heating of the polyimide foil. The simulation resulted in the temporal and spatial distribution of the estimated temperature in the irradiated polyimide sample, which are important for understanding the structure formation process.

  10. Effect of Space Radiation Processing on Lunar Soil Surface Chemistry: X-Ray Photoelectron Spectroscopy Studies

    Science.gov (United States)

    Dukes, C.; Loeffler, M.J.; Baragiola, R.; Christoffersen, R.; Keller, J.

    2009-01-01

    Current understanding of the chemistry and microstructure of the surfaces of lunar soil grains is dominated by a reference frame derived mainly from electron microscopy observations [e.g. 1,2]. These studies have shown that the outermost 10-100 nm of grain surfaces in mature lunar soil finest fractions have been modified by the combined effects of solar wind exposure, surface deposition of vapors and accretion of impact melt products [1,2]. These processes produce surface-correlated nanophase Feo, host grain amorphization, formation of surface patinas and other complex changes [1,2]. What is less well understood is how these changes are reflected directly at the surface, defined as the outermost 1-5 atomic monolayers, a region not easily chemically characterized by TEM. We are currently employing X-ray Photoelectron Spectroscopy (XPS) to study the surface chemistry of lunar soil samples that have been previously studied by TEM. This work includes modification of the grain surfaces by in situ irradiation with ions at solar wind energies to better understand how irradiated surfaces in lunar grains change their chemistry once exposed to ambient conditions on earth.

  11. Analysis the complex interaction among flexible nanoparticles and materials surface in the mechanical polishing process

    Energy Technology Data Exchange (ETDEWEB)

    Han Xuesong, E-mail: hanxuesongphd@yahoo.com.cn [School of Mechanical Engineering, Tianjin University, 300072 (China); Gan, Yong X. [Department of Mechanical, Industrial and Manufacturing Engineering, University of Toledo, OH 43606 (United States)

    2011-02-01

    Mechanical polishing (MP), being the important technique of realizing the surface planarization, has already been widely applied in the area of microelectronic manufacturing and computer manufacturing technology. The surface planarization in the MP is mainly realized by mechanical process which depended on the microdynamic behavior of nanoparticle. The complex multibody interaction among nanoparticles and materials surface is different from interaction in the macroscopic multibody system which makes the traditional classical materials machining theory cannot accurately uncover the mystery of the surface generation in the MP. Large-scale classical molecular dynamic (MD) simulation of interaction among nanoparticles and solid surface has been carried out to investigate the physical essence of surface planarization. The particles with small impact angle can generate more uniform global planarization surface but the materials removal rate is lower. The shear interaction between particle and substrate may induce large friction torque and lead to the rotation of particle. The translation plus rotation makes the nanoparticle behaved like micro-milling tool. The results show that the nanoparticles may aggregrate together and form larger cluster thus deteriorate surface the quality. This MD simulation results illuminate that the f inal planarized surface can only be acquired by synergic behavior of all particles using various means such as cutting, impacting, scratching, indentation and so on.

  12. AFM surface imaging of AISI D2 tool steel machined by the EDM process

    International Nuclear Information System (INIS)

    Guu, Y.H.

    2005-01-01

    The surface morphology, surface roughness and micro-crack of AISI D2 tool steel machined by the electrical discharge machining (EDM) process were analyzed by means of the atomic force microscopy (AFM) technique. Experimental results indicate that the surface texture after EDM is determined by the discharge energy during processing. An excellent machined finish can be obtained by setting the machine parameters at a low pulse energy. The surface roughness and the depth of the micro-cracks were proportional to the power input. Furthermore, the AFM application yielded information about the depth of the micro-cracks is particularly important in the post treatment of AISI D2 tool steel machined by EDM

  13. AFM surface imaging of AISI D2 tool steel machined by the EDM process

    Science.gov (United States)

    Guu, Y. H.

    2005-04-01

    The surface morphology, surface roughness and micro-crack of AISI D2 tool steel machined by the electrical discharge machining (EDM) process were analyzed by means of the atomic force microscopy (AFM) technique. Experimental results indicate that the surface texture after EDM is determined by the discharge energy during processing. An excellent machined finish can be obtained by setting the machine parameters at a low pulse energy. The surface roughness and the depth of the micro-cracks were proportional to the power input. Furthermore, the AFM application yielded information about the depth of the micro-cracks is particularly important in the post treatment of AISI D2 tool steel machined by EDM.

  14. Method for atmospheric pressure reactive atom plasma processing for surface modification

    Science.gov (United States)

    Carr, Jeffrey W [Livermore, CA

    2009-09-22

    Reactive atom plasma processing can be used to shape, polish, planarize and clean the surfaces of difficult materials with minimal subsurface damage. The apparatus and methods use a plasma torch, such as a conventional ICP torch. The workpiece and plasma torch are moved with respect to each other, whether by translating and/or rotating the workpiece, the plasma, or both. The plasma discharge from the torch can be used to shape, planarize, polish, and/or clean the surface of the workpiece, as well as to thin the workpiece. The processing may cause minimal or no damage to the workpiece underneath the surface, and may involve removing material from the surface of the workpiece.

  15. Manipulating surface wettability and oil absorbency of diatomite depending on processing and ambient conditions

    Science.gov (United States)

    Özen, İlhan; Şimşek, Süleyman; Okyay, Gamze

    2015-03-01

    In this study, a diatomite sample, which is a natural inorganic mineral with inherently high water and oil absorption capacity, was subjected to grinding before surface modification. Afterwards, the diatomite surface was modified via facile methods using a fluorocarbon (FC) chemical and stearic acid (SA) in addition to the sol-gel fluorosilanization (FS) process. The water and oil wettability, and oil absorbency properties of the unmodified and modified diatomites were investigated in addition to diatomite characterizations such as chemical content, surface area, particle size distribution, morphology, and modification efficiency. It was revealed that the wettability was changed completely depending on the surface modification agent and the media used, while the oil absorbency property surprisingly did not change. On the other hand, the oil absorbency was worsened by the grinding process, whereas the wettability was not affected.

  16. Surface spectroscopic characterization of a model methane-activation catalyst

    International Nuclear Information System (INIS)

    Chen, J.G.; Weisel, M.D.; Hoffmann, F.M.; Hall, R.B.

    1992-01-01

    In an effort to understand the details concerning the alkali-promoted selectivity for the oxidative coupling of methane, the authors have carried out a detailed characterization of a model K/NiO/Ni(100) catalyst under well-controlled, ultrahigh vacuum conditions. The authors' systematic approach involved the following procedures: detailed investigation of the formation and structure of NiO on a clean Ni(100) surface; spectroscopic characterization of K-doped NiO by in situ deposition of potassium onto well-characterized NiO/Ni(100) substrate; and determination of the reactivities of NiO/Ni(100) and K/NiO/Ni(100) towards H 2 and CH 4 . In this paper, the authors will use the model K/NiO/Ni(100) system as an example to demonstrate that a detailed, complementary characterization of the model catalyst could best be achieved by using a combination of a variety of surface techniques: The methods of HREELS, LEED, XPS and AES could be applied to obtain properties on and near the surface regions; the technique of FYNES, being a photon-in/photon-out method could be utilized to investigate the bulk properties up to 2000 Angstrom below the surface; the method of FTIR using CO as a probing molecule is, on the other hand, sensitive only to the properties of the top-most surface layer. The result is to be presented in this paper will be mainly those obtained by using the two vibrational spectroscopies (HREELS and FTIR). Results from other surface techniques will also be discussed or presented when they provide additional information to the vibrational data

  17. The influence of carrier density and doping type on lithium insertion and extraction processes at silicon surfaces

    International Nuclear Information System (INIS)

    McSweeney, W.; Lotty, O.; Glynn, C.; Geaney, H.; Holmes, J.D.; O’Dwyer, C.

    2014-01-01

    The Li + insertion and extraction characteristics at n-type and p-type Si(100) electrodes with different carrier density and doping type are investigated by cyclic voltammetry and constant current measurements. The insertion and extraction potentials are demonstrated to vary with cycling and the occurrence of an activation effect is shown in n-type electrodes where the charge capacity and voltammetric currents are found to be much higher than p-type electrodes. A rate-dependent redox process influenced by the surface region electronic density, which influences the magnitude of cyclic voltammetry current is found at Si(100) surface regions during Li insertion and extraction. At p-type Si(100) surface regions, a thin, uniform film forms at lower currents, while also showing a consistently high (>70%) Coulombic efficiency for Li extraction. The p-type Si(100) surface region does not undergo crack formation after deintercalation and the amorphization was demonstrated using transmission electron microscopy (TEM). X-ray photoelectron spectroscopy (XPS) and Raman scattering demonstrate that highly doped n-type Si(100) retains Li as a silicide and converts to an amorphous phase as a two-step phase conversion process. The findings show the succinct dependence of Li insertion and extraction processes for uniformly doped Si(100) single crystals and how the doping type and its effect on the semiconductor-solution interface dominate Li insertion and extraction, composition, crystallinity changes and charge capacity

  18. The study of sub-surface damage distributions during grinding process on different abrasion materials

    Science.gov (United States)

    Kuo, Ching-Hsiang; Huang, Chien-Yao; Yu, Zong-Ru; Shu, Shyu-Cheng; Chang, Keng-Shou; Hsu, Wei-Yao

    2017-10-01

    The grinding process is the primary technology for curvature generation (CG) on glass optics. The higher material removal rate (MRR) leads to deeper sub-surface damage (SSD) on lens surface. The SSD must be removed by following lapping and polishing processes to ensure the lens quality. However, these are not an easy and an efficient process to remove the SSD from ground surface directly for aspheric surfaces with tens or hundreds microns departure from bestfit- sphere (BFS). An efficient fabrication procedure for large aspheric departure on glass materials must be considered. We propose 3-step fabrication procedures for aspheric surface with larger departure. 1st step is to generate a specific aspheric surface with depth less than 10 μm of SSD residual. 2nd step is to remove SSD and keep the aspheric form by using Zeeko polisher with higher MRR pad. Final step is to figure and finish the aspheric surface by using QED MRF machine. In this study, we focus on the 1st step to investigate the residual depth of SSD after grinding process on different abrasion materials. The materials of tested part are fused silica, S-NPH2, and S-PHM52. The cross grinding would be configured and depth of SSD/surface roughness would be evaluated in this study. The characteristic of SSD could be observed after etching by confocal microscope. The experimental results show the depth of SSD below 31.1 μm with #400 grinding wheel. And the near 10 μm depth of SSD would be achieved with #1,000 grinding wheel. It means the aspherization polishing on large parts with large departure from best fit sphere would be replaced. The fabrication of large aspheric part would be efficient.

  19. Influence of Wire Electrical Discharge Machining (WEDM) process parameters on surface roughness

    Science.gov (United States)

    Yeakub Ali, Mohammad; Banu, Asfana; Abu Bakar, Mazilah

    2018-01-01

    In obtaining the best quality of engineering components, the quality of machined parts surface plays an important role. It improves the fatigue strength, wear resistance, and corrosion of workpiece. This paper investigates the effects of wire electrical discharge machining (WEDM) process parameters on surface roughness of stainless steel using distilled water as dielectric fluid and brass wire as tool electrode. The parameters selected are voltage open, wire speed, wire tension, voltage gap, and off time. Empirical model was developed for the estimation of surface roughness. The analysis revealed that off time has a major influence on surface roughness. The optimum machining parameters for minimum surface roughness were found to be at a 10 V open voltage, 2.84 μs off time, 12 m/min wire speed, 6.3 N wire tension, and 54.91 V voltage gap.

  20. Effect of Build Angle on Surface Properties of Nickel Superalloys Processed by Selective Laser Melting

    Science.gov (United States)

    Covarrubias, Ernesto E.; Eshraghi, Mohsen

    2018-03-01

    Aerospace, automotive, and medical industries use selective laser melting (SLM) to produce complex parts through solidifying successive layers of powder. This additive manufacturing technique has many advantages, but one of the biggest challenges facing this process is the resulting surface quality of the as-built parts. The purpose of this research was to study the surface properties of Inconel 718 alloys fabricated by SLM. The effect of build angle on the surface properties of as-built parts was investigated. Two sets of sample geometries including cube and rectangular artifacts were considered in the study. It was found that, for angles between 15° and 75°, theoretical calculations based on the "stair-step" effect were consistent with the experimental results. Downskin surfaces showed higher average roughness values compared to the upskin surfaces. No significant difference was found between the average roughness values measured from cube and rectangular test artifacts.

  1. Oxide-cathode activation and surface temperature calculation of electron cooler

    International Nuclear Information System (INIS)

    Li Jie; Yang Xiaodong; Mao Lijun; Li Guohong; Yuan Youjin; Liu Zhanwen; Zhang Junhui; Yang Xiaotian; Ma Xiaoming; Yan Tailai

    2011-01-01

    The pollution on electron gun ceramic insulation of electron cooler restricted the operation of electron cooler at HIRFL-CSR main ring. To cool and accumulate ion beam well, the pollution was cleared and a new oxide-coated cathode was assembled. The processes of cathode replacement,vacuum chamber baking-out, and thermal decomposition of coating binders and alkaline earth metal carbonates, and cathode activation are presented. The electron gun perveance of 10.6 μA/V 1.5 was attained under the heating power of 60 W. The typical surface temperature of oxide-coated cathode that is calculated through grey-body radiation is 1 108 K which shows a comparable result to the experimental measurement 1 078 K. The perveance growth of electron gun during the electron cooler operation is also explained by partial activation of the cathode. (authors)

  2. Development of RISA (radiation induced surface activation) detectors for onsite sensing and microdosimetry

    International Nuclear Information System (INIS)

    Date, H.; Shimozuma, M.; Tomozawa, H.; Takamasa, T.; Okamoto, K.

    2003-01-01

    We investigate a new technique for radiation detection using radiation induced surface activation (RISA) phenomenon which is found in oxide materials (with high resistivity) causing current conduction through the irradiation of gamma or beta rays. The RISA current has been observed typically in Rutile-type TiO 2 . We have performed a Monte Carlo simulation of gamma ray photons in TiO 2 and backing layers to make clear carrier generation processes leading to the conduction and to develop new type detectors for onsite sensing and microdosimetry. Results show that the dominant process to generate electron-hole pairs in thin TiO 2 layer is collisional interaction of electrons generated in backing layer, which suggest the RISA detector can be used for estimating the absorbed dose in bio-materials. (author)

  3. Sub-surface defects detection of by using active thermography and advanced image edge detection

    International Nuclear Information System (INIS)

    Tse, Peter W.; Wang, Gaochao

    2017-01-01

    Active or pulsed thermography is a popular non-destructive testing (NDT) tool for inspecting the integrity and anomaly of industrial equipment. One of the recent research trends in using active thermography is to automate the process in detecting hidden defects. As of today, human effort has still been using to adjust the temperature intensity of the thermo camera in order to visually observe the difference in cooling rates caused by a normal target as compared to that by a sub-surface crack exists inside the target. To avoid the tedious human-visual inspection and minimize human induced error, this paper reports the design of an automatic method that is capable of detecting subsurface defects. The method used the technique of active thermography, edge detection in machine vision and smart algorithm. An infrared thermo-camera was used to capture a series of temporal pictures after slightly heating up the inspected target by flash lamps. Then the Canny edge detector was employed to automatically extract the defect related images from the captured pictures. The captured temporal pictures were preprocessed by a packet of Canny edge detector and then a smart algorithm was used to reconstruct the whole sequences of image signals. During the processes, noise and irrelevant backgrounds exist in the pictures were removed. Consequently, the contrast of the edges of defective areas had been highlighted. The designed automatic method was verified by real pipe specimens that contains sub-surface cracks. After applying such smart method, the edges of cracks can be revealed visually without the need of using manual adjustment on the setting of thermo-camera. With the help of this automatic method, the tedious process in manually adjusting the colour contract and the pixel intensity in order to reveal defects can be avoided. (paper)

  4. Synthesis of surface oxygen-deficient BiPO{sub 4} nanocubes with enhanced visible light induced photocatalytic activity

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Bingtao; Yin, Haoyong; Li, Tao; Gong, Jianying; Lv, Shumei; Nie, Qiulin, E-mail: yhy@hdu.edu.cn [College of Materials & Environmental Engineering, Hangzhou Dianzi University, Hangzhou (China)

    2017-05-15

    The visible light driven BiPO{sub 4} nanocubes with sufficient surface oxygen deficiency were fabricated by a hydrothermal process and subsequently ultrasonic assistant Fe reduction process. The products were characterized by XRD, DRS, XPS, SEM and TEM which showed that the BiPO{sub 4} had cuboid-like shape with a smooth surface and clear edges and the oxygen vacancies were successfully introduced on the surface of the BiPO{sub 4} nanocubes. The as prepared oxygen-deficient BiPO{sub 4} nanocubes showed greatly enhanced visible light induced photocatalytic activity in degradation of Rhodamine B. The enhanced photocatalytic performance and expanded visible light response of BiPO{sub 4} may be due to the introduction of surface oxygen vacancies which can generate the oxygen vacancies mid-gap states lower to the conduction band of BiPO{sub 4}. (author)

  5. Insights into the Surface Transformation and Electrochemical Dissolution Process of Bornite in Bioleaching

    Directory of Open Access Journals (Sweden)

    Hongbo Zhao

    2018-04-01

    Full Text Available In this work, density functional theory (DFT calculations, X-ray photoelectron spectroscopy (XPS and electrochemistry analysis were combined to analyze the electrochemical dissolution process of bornite during bioleaching. DFT calculations showed that bornite was a conductor with metallic conductivity. The formula of bornite may be (Cu+5Fe3+(S2−4 and the surface reconstruction of (111-S surface was discussed. Electrochemistry and XPS analysis showed that bornite tended to be directly oxidized with high conductivity when the potential was higher than 0.3 V vs. Ag/AgCl. Elemental sulfur (S0, FeOOH and CuS were the main intermediate species on the bornite surface during the oxidation process. The production of S0 and FeOOH on bornite surface can be significantly accelerated with increased redox potential, but no insoluble sulfate (SO42− formed on bornite surface in 0.3–0.65 V vs. Ag/AgCl. The oxidative dissolution of bornite was significantly accelerated with increasing redox potential, which was one important reason why mixed culture was more effective than single strains of A. caldus and L. ferriphilum in bornite bioleaching. The insoluble SO42− was formed mainly through the chemical reactions in solution and then covered the bornite surface in bioleaching. Based on the obtained results, a model for interpreting the dissolution process of bornite in bioleaching was proposed.

  6. Land Surface Process and Air Quality Research and Applications at MSFC

    Science.gov (United States)

    Quattrochi, Dale; Khan, Maudood

    2007-01-01

    This viewgraph presentation provides an overview of land surface process and air quality research at MSFC including atmospheric modeling and ongoing research whose objective is to undertake a comprehensive spatiotemporal analysis of the effects of accurate land surface characterization on atmospheric modeling results, and public health applications. Land use maps as well as 10 meter air temperature, surface wind, PBL mean difference heights, NOx, ozone, and O3+NO2 plots as well as spatial growth model outputs are included. Emissions and general air quality modeling are also discussed.

  7. Bioinspired superhydrophobic surfaces, fabricated through simple and scalable roll-to-roll processing.

    Science.gov (United States)

    Park, Sung-Hoon; Lee, Sangeui; Moreira, David; Bandaru, Prabhakar R; Han, InTaek; Yun, Dong-Jin

    2015-10-22

    A simple, scalable, non-lithographic, technique for fabricating durable superhydrophobic (SH) surfaces, based on the fingering instabilities associated with non-Newtonian flow and shear tearing, has been developed. The high viscosity of the nanotube/elastomer paste has been exploited for the fabrication. The fabricated SH surfaces had the appearance of bristled shark skin and were robust with respect to mechanical forces. While flow instability is regarded as adverse to roll-coating processes for fabricating uniform films, we especially use the effect to create the SH surface. Along with their durability and self-cleaning capabilities, we have demonstrated drag reduction effects of the fabricated films through dynamic flow measurements.

  8. Evaporation phase change processes of water/methanol mixtures on superhydrophobic nanostructured surfaces

    Science.gov (United States)

    Chiang, Cheng-Kun; Lu, Yen-Wen

    2011-07-01

    Evaporation phenomena are a critical and frequently seen phase change process in many heat transfer applications. In this paper, we study the evaporation process of a sessile droplet on two topologically different surfaces, including smooth and nanostructured surfaces. The nanostructured surface has an array of high-aspect-ratio nanowires (height/diameter ~ 125) and is implemented by using a simple template-based nanofabrication method. It possesses superhydrophobicity (>140°) and low contact angle hysteresis (1.2-2.1°), allowing the liquid droplets to remain in the 'fakir' state throughout the evaporation processes. Sessile droplets of deionized (DI) water and water/methanol binary mixture test liquids with their contact angles and base diameters are monitored. The results show that the nanostructures play a critical role in the droplet dynamics during evaporation.

  9. Evaporation phase change processes of water/methanol mixtures on superhydrophobic nanostructured surfaces

    International Nuclear Information System (INIS)

    Chiang, Cheng-Kun; Lu, Yen-Wen

    2011-01-01

    Evaporation phenomena are a critical and frequently seen phase change process in many heat transfer applications. In this paper, we study the evaporation process of a sessile droplet on two topologically different surfaces, including smooth and nanostructured surfaces. The nanostructured surface has an array of high-aspect-ratio nanowires (height/diameter ∼ 125) and is implemented by using a simple template-based nanofabrication method. It possesses superhydrophobicity (>140°) and low contact angle hysteresis (1.2–2.1°), allowing the liquid droplets to remain in the 'fakir' state throughout the evaporation processes. Sessile droplets of deionized (DI) water and water/methanol binary mixture test liquids with their contact angles and base diameters are monitored. The results show that the nanostructures play a critical role in the droplet dynamics during evaporation

  10. Selection Criteria and Methods for Testing Different Surface Materials for Contact Frying Processes

    DEFF Research Database (Denmark)

    Ashokkumar, Saranya

    Inner surfaces of industrial process equipment for food are often coated to give the surfaces particular properties with respect to adhesion and cleanability. Existing coating materials (PTFE (Teflon®) or silicone based polymers) suffer from drawbacks when used in contact frying, because these co...... surface materials for contact frying processes. The surfaces selected for this purpose cover a wide spectrum of materials that range from hydrophobic to hydrophilic materials. The different surface materials investigated include stainless steel (reference), aluminium (Al Mg 5754), PTFE......, an experimental rig has been constructed which enabled a controlled fouling of different coatings on steel and aluminium substrates under realistic frying conditions. A subjective rating procedure was employed for screening different surfaces according to their non-stick properties when used for frying of a model...... defects and surface roughness play a significant role. The wear resistance of the coatings was tested by performing abrasive wear experiments. The ceramic coatings: TiAlN and ZrN were found to show the best wear resistance properties. The experiments also revealed the poor wear resistance of stainless...

  11. Supply capability creation process: Key milestone criteria and activities

    Energy Technology Data Exchange (ETDEWEB)

    Verrollot, J.; Tolonen, A.; Harkonen, J.; Haapasalo, H.

    2017-07-01

    The article focuses on supply capability creation (SCC) within the new product development (NPD). The purpose is to establish an SCC process describing the main SCC activities and milestone criteria in preparing the supply process for new products Design/methodology/approach: The article analyses the earlier research, carries out current state analysis of six case companies regarding the SCC areas, and proposes a SCC process. Findings: The developed SCC process aims at preparing the operational supply capability for a developed new product based on the preferred, qualified and contracted suppliers and materials along the NPD process, and ultimately at the product ramp-up. Originality/value: This paper introduces a SCC process that has not been presented earlier in the literature, highlighting the important role of the SCC for successful product ramp-ups.

  12. Supply capability creation process: Key milestone criteria and activities

    Directory of Open Access Journals (Sweden)

    Jordan Verrollot

    2017-09-01

    Full Text Available Purpose: The article focuses on supply capability creation (SCC within the new product development (NPD. The purpose is to establish an SCC process describing the main SCC activities and milestone criteria in preparing the supply process for new products Design/methodology/approach: The article analyses the earlier research, carries out current state analysis of six case companies regarding the SCC areas, and proposes a SCC process. Findings: The developed SCC process aims at preparing the operational supply capability for a developed new product based on the preferred, qualified and contracted suppliers and materials along the NPD process, and ultimately at the product ramp-up. Originality/value: This paper introduces a SCC process that has not been presented earlier in the literature, highlighting the important role of the SCC for successful product ramp-ups.

  13. Using of the surface activation method for enhancement of machine realibility

    International Nuclear Information System (INIS)

    Postnikov, V.I.; Garbar, I.N.

    1979-01-01

    A surface activation method is described for controlling the wear of units and details, allowing one to measure the wear at continuous operation of the mechanism by any program. The main advantages of the surface activation method for the wear tests are shown. By means of that method it was possible to develop a simultaneous controlling conjugate detail wear, and a method of different-activity brands, as well as the method for repeated activation of details. Development of theory for the engineering and technology of engine wear control by the surface activation method allowed one to improve the efficiency and reduce the time of research in the field of friction and wear

  14. Planarization of the diamond film surface by using the hydrogen plasma etching with carbon diffusion process

    International Nuclear Information System (INIS)

    Kim, Sung Hoon

    2001-01-01

    Planarization of the free-standing diamond film surface as smooth as possible could be obtained by using the hydrogen plasma etching with the diffusion of the carbon species into the metal alloy (Fe, Cr, Ni). For this process, we placed the free-standing diamond film between the metal alloy and the Mo substrate like a metal-diamond-molybdenum (MDM) sandwich. We set the sandwich-type MDM in a microwave-plasma-enhanced chemical vapor deposition (MPECVD) system. The sandwich-type MDM was heated over ca. 1000 .deg. C by using the hydrogen plasma. We call this process as the hydrogen plasma etching with carbon diffusion process. After etching the free-standing diamond film surface, we investigated surface roughness, morphologies, and the incorporated impurities on the etched diamond film surface. Finally, we suggest that the hydrogen plasma etching with carbon diffusion process is an adequate etching technique for the fabrication of the diamond film surface applicable to electronic devices

  15. Basic visual perceptual processes in children with typical development and cerebral palsy: The processing of surface, length, orientation, and position.

    Science.gov (United States)

    Schmetz, Emilie; Magis, David; Detraux, Jean-Jacques; Barisnikov, Koviljka; Rousselle, Laurence

    2018-03-02

    The present study aims to assess how the processing of basic visual perceptual (VP) components (length, surface, orientation, and position) develops in typically developing (TD) children (n = 215, 4-14 years old) and adults (n = 20, 20-25 years old), and in children with cerebral palsy (CP) (n = 86, 5-14 years old) using the first four subtests of the Battery for the Evaluation of Visual Perceptual and Spatial processing in children. Experiment 1 showed that these four basic VP processes follow distinct developmental trajectories in typical development. Experiment 2 revealed that children with CP present global and persistent deficits for the processing of basic VP components when compared with TD children matched on chronological age and nonverbal reasoning abilities.

  16. The impact on environment and population of the sands with radioactive heavy minerals processing activity

    International Nuclear Information System (INIS)

    Aurelian, F.; Popescu, M.; Georgescu, D.

    2006-01-01

    The paper presents a case study concerning the impact on environment and population of a Pilot Station, which was used between 1970 and 1996 to obtain mono-mineral concentrates (ilmenite, zircon, garnet, rutile, monazite) by processing alluvial and seashore sands. The processing technological flow sheet was constituted only of physical separation processes, where were operating equipments such as shaking tables, electric and magnetic separators, attrition equipments, etc. The paper is structured on three levels and presents: - A brief description of the Pilot Station activity, sand types processed and its physical, chemical and mineralogic characteristics. The obtained products were: garnets with 10 ppm uranium and 60 ppm thorium, ilmenite with 10 ppm uranium and 20 ppm thorium, zircon with 450 ppm uranium and 750 ppm thorium and monazite with 3,000 ppm uranium and 20,000 ppm thorium. The sterile accumulated during the Pilot Station functioning time is also characterized. - The impact of the Pilot Station activity on environment (soil, air). The contamination sources are identified and characterized. The only one contamination pathway is represented by 'radioactive dust' resulted from the sands processing activity. The contamination processes are explained and justified. The contaminated soil surface was investigated through: gamma rate doses determination (at the surface and on a depth o f up to 40 cm), measurement of Rn 222 + Rn 220 concentration at one meter distance from the surface and for 40 cm soil depth, analysis of uranium, radium and thorium for samples collected from a soil depth ranging between 10 and 40 cm. There were elaborated maps showing gamma rate doses distribution and the specific activity for the surface as well as for the different soil depths. It was established the contamination level and its value was compared to the ones stipulated by Romanian Nuclear Authority norms, namely 0.2 Bq/g for the specific activity (Ra 226 + Th 232) and 0.3

  17. Downstream Processability of Crystal Habit-Modified Active Pharmaceutical Ingredient

    DEFF Research Database (Denmark)

    Pudasaini, Nawin; Upadhyay, Pratik Pankaj; Parker, Christian Richard

    2017-01-01

    Efficient downstream processing of active pharmaceutical ingredients (APIs) can depend strongly on their particulate properties, such as size and shape distributions. Especially in drug products with high API content, needle-like crystal habit of an API may show compromised flowability and tablet......Efficient downstream processing of active pharmaceutical ingredients (APIs) can depend strongly on their particulate properties, such as size and shape distributions. Especially in drug products with high API content, needle-like crystal habit of an API may show compromised flowability...

  18. Lateralized frontal activity for Japanese phonological processing during child development

    Directory of Open Access Journals (Sweden)

    Takaaki eGoto

    2015-07-01

    Full Text Available Phonological awareness is essential for reading, and is common to all language systems, including alphabetic languages and Japanese. This cognitive factor develops during childhood, and is thought to be associated with shifts in brain activity. However, the nature of this neurobiological developmental shift is unclear for speakers of Japanese, which is not an alphabetical language. The present study aimed to reveal a shift in brain functions for processing phonological information in native-born Japanese children. We conducted a phonological awareness task and examined hemodynamic activity in 103 children aged 7 to 12 years. While younger children made mistakes and needed more time to sort phonological information in reverse order, older children completed the task quickly and accurately. Additionally, younger children exhibited increased activity in the bilateral dorsolateral prefrontal cortex, which may be evidence of immature phonological processing skills. Older children exhibited dominant activity in the left compared with the right dorsolateral prefrontal cortex, suggesting that they had already acquired phonological processing skills. We also found significant effects of age and lateralized activity on behavioral performance. During earlier stages of development, the degree of left lateralization appears to have a smaller effect on behavioral performance. Conversely, in later stages of development, the degree of left lateralization appears to have a stronger influence on behavioral performance. These initial findings regarding a neurobiological developmental shift in Japanese speakers suggest that common brain regions play a critical role in the development of phonological processing skills among different languages systems, such as Japanese and alphabetical languages.

  19. Activities relating to PSA in the regulatory process

    International Nuclear Information System (INIS)

    Campbell, J.F.; Grint, G.C.

    1994-01-01

    In addition to the IAEA activities concerning the use of PSA in the regulatory process there are two other international initiatives in this area by the European Commission and the OECD's Committee for Nuclear Regulatory Authorities (CRNA). The paper gives a brief outline of these activities as well as introducing an update on the regulatory use of PSA in the UK. 3 refs, 3 tabs

  20. Low and medium activity solid wastes processing and encapsulation

    International Nuclear Information System (INIS)

    Taillard, D.; Claes, J.; Hennart, D.

    1983-01-01

    This work, carried out under contract with the European Atomic Energy Community, describes the techniques in use for waste management. The activity of low and medium activity solid wastes is from few curies to few tens of curies per cubic meter, they are produced by nuclear facilities and are often complex mixtures. Radioactive wastes are characterized and processing and conditioning are described. Leaching, stability, mechanical resistance and radiolysis of encapsulated wastes are examined. Handling, storage and disposal are treated

  1. Active non-volatile memory post-processing

    Energy Technology Data Exchange (ETDEWEB)

    Kannan, Sudarsun; Milojicic, Dejan S.; Talwar, Vanish

    2017-04-11

    A computing node includes an active Non-Volatile Random Access Memory (NVRAM) component which includes memory and a sub-processor component. The memory is to store data chunks received from a processor core, the data chunks comprising metadata indicating a type of post-processing to be performed on data within the data chunks. The sub-processor component is to perform post-processing of said data chunks based on said metadata.

  2. Microstructure and optical appearance of anodized friction stir processed Al - Metal oxide surface composites

    DEFF Research Database (Denmark)

    Gudla, Visweswara Chakravarthy; Jensen, Flemming; Bordo, Kirill

    2014-01-01

    Multiple-pass friction stir processing (FSP) was employed to impregnate Ti, Y and Ce oxide powders into the surface of an Aluminium alloy. The FSP processed surface composite was subsequently anodized with an aim to develop optical effects in the anodized layer owing to the presence of incorporated...... oxide particles which will influence the scattering of light. This paper presents the investigations on relation between microstructure of the FSP zone and optical appearance of the anodized layer due to incorporation of metal oxide particles and modification of the oxide particles due to the anodizing...

  3. Process for growing a film epitaxially upon a MGO surface and structures formed with the process

    Science.gov (United States)

    McKee, Rodney Allen; Walker, Frederick Joseph

    1998-01-01

    A process and structure wherein optical quality perovskites, such as BaTiO.sub.3 or SrTiO.sub.3, are grown upon a single crystal MgO substrate involves the epitaxial build up of alternating planes of TiO.sub.2 and metal oxide wherein the first plane grown upon the MgO substrate is a plane of TiO.sub.2. The layering sequence involved in the film build up reduces problems which would otherwise result from the interfacial electrostatics at the first atomic layers, and these oxides can be stabilized as commensurate thin films at a unit cell thickness or grown with high crystal quality to thicknesses of 0.5-0.7 .mu.m for optical device applications.

  4. Bismuth Ferrite for Active Control of Surface Plasmon Polariton Modes

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Zhukovsky, Sergei; Lavrinenko, Andrei

    2014-01-01

    We propose and investigate several layouts of m etal-insulator-metal waveguide with active core which can be utilized for dynamic switching in photonic integrated circuits. The active material, bismuth ferrite (BiFeO3), is sandwiched between metal plates and changes i ts refractive index through...

  5. Note: A single-chamber tool for plasma activation and surface functionalization in microfabrication

    Energy Technology Data Exchange (ETDEWEB)

    Bowman, Adam J.; Scherrer, Joseph R.; Reiserer, Ronald S., E-mail: ron.reiserer@vanderbilt.edu [Vanderbilt Institute for Integrative Biosystems Research and Education and Department of Physics and Astronomy, Vanderbilt University, Nashville, Tennessee 37235 (United States)

    2015-06-15

    We present a simple apparatus for improved surface modification of polydimethylsiloxane (PDMS) microfluidic devices. A single treatment chamber for plasma activation and chemical/physical vapor deposition steps minimizes the time-dependent degradation of surface activation that is inherent in multi-chamber techniques. Contamination and deposition irregularities are also minimized by conducting plasma activation and treatment phases in the same vacuum environment. An inductively coupled plasma driver allows for interchangeable treatment chambers. Atomic force microscopy confirms that silane deposition on PDMS gives much better surface quality than standard deposition methods, which yield a higher local roughness and pronounced irregularities in the surface.

  6. Effect of sulfation on the surface activity of CaO for N{sub 2}O decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Lingnan, E-mail: wulingnan@126.com [School of Energy, Power and Mechanical Engineering, North China Electric Power University, 102206 Beijing (China); National Engineering Laboratory for Biomass Power Generation Equipment, North China Electric Power University, 102206 Beijing (China); Hu, Xiaoying, E-mail: huxy@ncepu.edu.cn [National Engineering Laboratory for Biomass Power Generation Equipment, North China Electric Power University, 102206 Beijing (China); Qin, Wu, E-mail: qinwugx@126.com [National Engineering Laboratory for Biomass Power Generation Equipment, North China Electric Power University, 102206 Beijing (China); Dong, Changqing, E-mail: cqdong1@163.com [National Engineering Laboratory for Biomass Power Generation Equipment, North China Electric Power University, 102206 Beijing (China); Yang, Yongping, E-mail: yypncepu@163.com [School of Energy, Power and Mechanical Engineering, North China Electric Power University, 102206 Beijing (China)

    2015-12-01

    Graphical abstract: - Highlights: • Sulfation of CaO (1 0 0) surface greatly deactivates its surface activity for N{sub 2}O decomposition. • An increase of sulfation degree leads to a decrease of CaO surface activity for N{sub 2}O decomposition. • Sulfation from CaSO{sub 3} into CaSO{sub 4} is the crucial step for deactivating the surface activity for N{sub 2}O decomposition. • The electronic interaction CaO (1 0 0)/CaSO{sub 4} (0 0 1) interface is limited to the bottom layer of CaSO{sub 4} (0 0 1) and the top layer of CaO (1 0 0). • CaSO{sub 4} (0 0 1) and (0 1 0) surfaces show negligible catalytic ability for N{sub 2}O decomposition. - Abstract: Limestone addition to circulating fluidized bed boilers for sulfur removal affects nitrous oxide (N{sub 2}O) emission at the same time, but mechanism of how sulfation process influences the surface activity of CaO for N{sub 2}O decomposition remains unclear. In this paper, we investigated the effect of sulfation on the surface properties and catalytic activity of CaO for N{sub 2}O decomposition using density functional theory calculations. Sulfation of CaO (1 0 0) surface by the adsorption of a single gaseous SO{sub 2} or SO{sub 3} molecule forms stable local CaSO{sub 3} or CaSO{sub 4} on the CaO (1 0 0) surface with strong hybridization between the S atom of SO{sub x} and the surface O anion. The formed local CaSO{sub 3} increases the barrier energy of N{sub 2}O decomposition from 0.989 eV (on the CaO (1 0 0) surface) to 1.340 eV, and further sulfation into local CaSO{sub 4} remarkably increases the barrier energy to 2.967 eV. Sulfation from CaSO{sub 3} into CaSO{sub 4} is therefore the crucial step for deactivating the surface activity for N{sub 2}O decomposition. Completely sulfated CaSO{sub 4} (0 0 1) and (0 1 0) surfaces further validate the negligible catalytic ability of CaSO{sub 4} for N{sub 2}O decomposition.

  7. Influence of surface mechanical activation of the X40Cr13 steel on roughness after ion and gas nitriding

    International Nuclear Information System (INIS)

    Jasinski, J.; Wojtal, A.; Jeziorski, L.; Radecki, A.; Ucieklak, S.

    2003-01-01

    The article describes the problem of the thermal and mechanical activation of the surface of the X40Cr13 steel on the state of the ion and gas nitriding. in order to determine the nitriding influence and make the analysis of results, the steel was subjected to: soft annealing, hardening with subsequent tempering at T = 550 o C and also mechanical activation of the surface consisting in peripheral grinding with abrasive papers of the grain size 60, 360, 1000 and mechanical polishing. The main aim of this work was to establish the influence of different surface geometrical structure, depending on X40Cr13 steel structure, on the roughness profile after ion and gas nitriding. With regard to the above, the examinations of basic roughness parameters prior to and after thermochemical processes and the analysis of utilitarian usefulness of activations applied were carried out. (author)

  8. Increased cell surface metallopeptidase activity in cells undergoing UV-induced apoptosis

    International Nuclear Information System (INIS)

    Piva, T.J.; Davern, C.M.; Ellem, K.A.O.

    1999-01-01

    Full text: We have previously shown that UVC irradiation activated a range of cell surface peptidases (CSP) in HeLa cell monolayer cultures 20 h post-irradiation (1). In cells undergoing apoptosis there is an increase in CSP activity compared to control viable cells in cultures which have been treated by a wide range of agents including UV-irradiation (2). In order to further understand the mechanism involved in this process, we induced apoptosis in HeLa cells using 500 Jm -2 UVB. The separation of viable, apoptotic and necrotic cells of irradiated HeLa cell cultures was made by FACS analysis and sorting. The three populations were distinguished by their staining with PI and Hoechst 33342 dyes. CSP activity was measured using the P9 assay developed in this laboratory (1-3). The viable fraction of the irradiated cells had a higher level of CSP activity compared to unirradiated controls. The level of CSP activity in the apoptotic fraction was higher than that of the viable fraction, however that of the necrotic fraction was significantly lower. This finding agreed with that seen in UVC-irradiated (50 Jm -2 ) cultures (2). In order to elucidate the mechanism by which CSP activity was increased in UVB-irradiated cells undergoing apoptosis, the cultures were treated with the following agents: bestatin, aminopeptidase inhibitor, DEVD, caspase 3 inhibitor, and 3-aminobenzamide (3AB), PARP activation inhibitor. Bestatin and DEVD did not affect the level of CSP activity in the different cell subpopulations following UVB-irradiation. Treatment with 3AB abolished the increased CSP activity seen in the viable and apoptotic fraction following UVB-irradiation. All treated cells had the same morphology as observed under EM. The degree of phosphatidylserine eversion on the cell membrane was similar as were the cleavage profiles of PARP and actin. Only DEVD-treated cells had reduced caspase 3 activity which confirmed that the activation of CSP activity in apoptotic cells is

  9. Surface roughening of ground fused silica processed by atmospheric inductively coupled plasma

    International Nuclear Information System (INIS)

    Xin, Qiang; Li, Na; Wang, Jun; Wang, Bo; Li, Guo; Ding, Fei; Jin, Huiliang

    2015-01-01

    Highlights: • The morphology evolution of ground fused silica, processed by atmospheric plasma, was investigated experimentally. • The roughness development results from opening and coalescing of the plasma-etched cracks. • The shapes of grain-like etched pits are the results of the adjacent cracks coalescing with one another. • The descent of the pits density is due to some smaller etched pits that are swallowed up by larger pits. • Leading role in surface smoothing is laterally etching away the side walls of the intersecting pits. - Abstract: Subsurface damage (SSD) is a defect that is inevitably induced during mechanical processes, such as grinding and polishing. This defect dramatically reduces the mechanical strength and the laser damage thresholds of optical elements. Compared with traditional mechanical machining, atmospheric pressure plasma processing (APPP) is a relatively novel technology that induces almost no SSD during the processing of silica-based optical materials. In this paper, a form of APPP, inductively coupled plasma (ICP), is used to process fused silica substrates with fluorocarbon precursor under atmospheric pressure. The surface morphology evolution of ICP-processed substrates was observed and characterized by confocal laser scanning microscope (CLSM), field emission scanning electron microscope (SEM), and atomic force microscopy (AFM). The results show that the roughness evolves with the etching depth, and the roughness evolution is a single-peaked curve. This curve results from the opening and the coalescing of surface cracks and fractures. The coalescence procedure of these microstructures was simulated with two common etched pits on a polished fused silica surface. Understanding the roughness evolution of plasma-processed surface might be helpful in optimizing the optical fabrication chain that contains APPP

  10. Surface roughening of ground fused silica processed by atmospheric inductively coupled plasma

    Energy Technology Data Exchange (ETDEWEB)

    Xin, Qiang; Li, Na; Wang, Jun; Wang, Bo, E-mail: bradywang@hit.edu.cn; Li, Guo; Ding, Fei; Jin, Huiliang

    2015-06-30

    Highlights: • The morphology evolution of ground fused silica, processed by atmospheric plasma, was investigated experimentally. • The roughness development results from opening and coalescing of the plasma-etched cracks. • The shapes of grain-like etched pits are the results of the adjacent cracks coalescing with one another. • The descent of the pits density is due to some smaller etched pits that are swallowed up by larger pits. • Leading role in surface smoothing is laterally etching away the side walls of the intersecting pits. - Abstract: Subsurface damage (SSD) is a defect that is inevitably induced during mechanical processes, such as grinding and polishing. This defect dramatically reduces the mechanical strength and the laser damage thresholds of optical elements. Compared with traditional mechanical machining, atmospheric pressure plasma processing (APPP) is a relatively novel technology that induces almost no SSD during the processing of silica-based optical materials. In this paper, a form of APPP, inductively coupled plasma (ICP), is used to process fused silica substrates with fluorocarbon precursor under atmospheric pressure. The surface morphology evolution of ICP-processed substrates was observed and characterized by confocal laser scanning microscope (CLSM), field emission scanning electron microscope (SEM), and atomic force microscopy (AFM). The results show that the roughness evolves with the etching depth, and the roughness evolution is a single-peaked curve. This curve results from the opening and the coalescing of surface cracks and fractures. The coalescence procedure of these microstructures was simulated with two common etched pits on a polished fused silica surface. Understanding the roughness evolution of plasma-processed surface might be helpful in optimizing the optical fabrication chain that contains APPP.

  11. Developments of a bonding technique for optical materials by a surface activation method

    International Nuclear Information System (INIS)

    Sugiyama, Akira; Oda, Tomohiro; Abe, Tomoyuki; Kusunoki, Isao

    2005-01-01

    We started developing the laser crystal bounding by the surface activation method which can splice crystals together without using hydrogen bonding. For the surface activation, neutral argon beams were used for irradiation of specimens. In the bonding trials with sapphire crystals, we recognized possibility of the bonding method for optical elements. (author)

  12. Characterization of boron carbide particulate reinforced in situ copper surface composites synthesized using friction stir processing

    Energy Technology Data Exchange (ETDEWEB)

    Sathiskumar, R., E-mail: sathiscit2011@gmail.com [Department of Mechanical Engineering, Coimbatore Institute of Technology, Coimbatore, 641 014 Tamil Nadu (India); Murugan, N., E-mail: murugan@cit.edu.in [Department of Mechanical Engineering, Coimbatore Institute of Technology, Coimbatore, 641 014 Tamil Nadu (India); Dinaharan, I., E-mail: dinaweld2009@gmail.com [Department of Mechanical Engineering, V V College of Engineering, Tisaiyanvilai, 627 657 Tamil Nadu (India); Vijay, S.J., E-mail: vijayjoseph@karunya.edu [Centre for Research in Metallurgy (CRM), School of Mechanical Sciences, Karunya University, Coimbatore, 641 114 Tamil Nadu (India)

    2013-10-15

    Friction stir processing has evolved as a novel solid state technique to fabricate surface composites. The objective of this work is to apply the friction stir processing technique to fabricate boron carbide particulate reinforced copper surface composites and investigate the effect of B{sub 4}C particles and its volume fraction on microstructure and sliding wear behavior of the same. A groove was prepared on 6 mm thick copper plates and packed with B{sub 4}C particles. The dimensions of the groove was varied to result in five different volume fractions of B{sub 4}C particles (0, 6, 12, 18 and 24 vol.%). A single pass friction stir processing was done using a tool rotational speed of 1000 rpm, travel speed of 40 mm/min and an axial force of 10 kN. Metallurgical characterization of the Cu/B{sub 4}C surface composites was carried out using optical microscope and scanning electron microscope. The sliding wear behavior was evaluated using a pin-on-disk apparatus. Results indicated that the B{sub 4}C particles significantly influenced the area, dispersion, grain size, microhardness and sliding wear behavior of the Cu/B{sub 4}C surface composites. When the volume fraction of B{sub 4}C was increased, the wear mode changed from microcutting to abrasive wear and wear debris was found to be finer. Highlights: • Fabrication of Cu/B{sub 4}C surface composite by friction stir processing • Analyzing the effect of B{sub 4}C particles on the properties of Cu/B4C surface composite • Increased volume fraction of B{sub 4}C particles reduced the area of surface composite. • Increased volume fraction of B{sub 4}C particles enhanced the microhardness and wear rate. • B{sub 4}C particles altered the wear mode from microcutting to abrasive.

  13. Quantification of chemical transport processes from the soil to surface runoff.

    Science.gov (United States)

    Tian, Kun; Huang, Chi-Hua; Wang, Guang-Qian; Fu, Xu-Dong; Parker, Gary

    2013-01-01

    There is a good conceptual understanding of the processes that govern chemical transport from the soil to surface runoff, but few studies have actually quantified these processes separately. Thus, we designed a laboratory flow cell and experimental procedures to quantify the chemical transport from soil to runoff water in the following individual processes: (i) convection with a vertical hydraulic gradient, (ii) convection via surface flow or the Bernoulli effect, (iii) diffusion, and (iv) soil loss. We applied different vertical hydraulic gradients by setting the flow cell to generate different seepage or drainage conditions. Our data confirmed the general form of the convection-diffusion equation. However, we now have additional quantitative data that describe the contribution of each individual chemical loading process in different surface runoff and soil hydrological conditions. The results of this study will be useful for enhancing our understanding of different geochemical processes in the surface soil mixing zone. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

  14. Monitoring RAYT activity by surface plasmon resonance biosensor

    Czech Academy of Sciences Publication Activity Database

    Bocková, Markéta; Špringer, Tomáš; Nečasová, Iva; Nunvář, Jaroslav; Schneider, Bohdan; Homola, Jiří

    2015-01-01

    Roč. 407, č. 14 (2015), s. 3985-3993 ISSN 1618-2642 R&D Projects: GA ČR GAP305/12/1801 Grant - others:GA MŠk(CZ) CZ.1.05/1.1.00/02.0109 Institutional support: RVO:67985882 ; RVO:86652036 Keywords : Surface plasmon resonance * Biosensor * REP-associated tyrosine transposase Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering; EB - Genetics ; Molecular Biology (BTO-N) Impact factor: 3.125, year: 2015

  15. Relationships among surface processing at the nanometer scale, nanostructure and optical properties of thin oxide films

    Energy Technology Data Exchange (ETDEWEB)

    Losurdo, Maria

    2004-05-01

    Spectroscopic ellipsometry is used to study the optical properties of nanostructured semiconductor oxide thin films. Various examples of models for the dielectric function, based on Lorentzian oscillators combined with the Drude model, are given based on the band structure of the analyzed oxide. With this approach, the optical properties of thin films are determined independent of the dielectric functions of the corresponding bulk materials, and correlation between the optical properties and nanostructure of thin films is investigated. In particular, in order to discuss the dependence of optical constants on grain size, CeO{sub 2} nanostructured films are considered and parameterized by two-Lorentzian oscillators or two-Tauc-Lorentz model depending on the nanostructure and oxygen deficiency. The correlation among anisotropy, crystalline fraction and optical properties parameterized by a four-Lorentz oscillator model is discussed for nanocrystalline V{sub 2}O{sub 5} thin films. Indium tin oxide thin films are discussed as an example of the presence of graded optical properties related to interfacial reactivity activated by processing conditions. Finally, the example of ZnO shows the potential of ellipsometry in discerning crystal and epitaxial film polarity through the analysis of spectra and the detection of surface reactivity of the two polar faces, i.e. Zn-polarity and O-polarity.

  16. Men’s artistic gymnastics: is the use of elastic surfaces systematic in the training process?

    Directory of Open Access Journals (Sweden)

    Marco Antonio Coelho BORTOLETO

    2016-03-01

    Full Text Available Abstract In Artistic Gymnastics, the area (the apparatus represents the most relevant systemic component. Thus, when one strives to comprehend the internal logic of this sport, the gymnast-apparatus relationship warrants special attention. A change in the training paradigm was observed, showing that the use of Elastic Surfaces (ES is an essential resource, due to the contemporary features of this sport, such as the hyper-valorisation of acrobatics and a greater presence of flight elements. Through a case study developed in a men’s artistic gymnastics high-performance gymnasium, this study analysed the use of different ES in the training process. Although coaches recognize the importance of ES in training programs, the record of daily activities showed that this use is still limited to select equipment and is not systematic. Such difficulties are due mainly to the lack of educational programs to the development of certain specific methodologies and the non-existence of national equipment suppliers certified by International Gymnastics Federation.

  17. Dropwise condensation heat transfer process optimisation on superhydrophobic surfaces using a multi-disciplinary approach

    International Nuclear Information System (INIS)

    Khatir, Z.; Kubiak, K.J.; Jimack, P.K.; Mathia, T.G.

    2016-01-01

    Highlights: • Droplets jumping phenomenon can enhance condensate evacuation from the surface. • Droplets jumping velocity depends on droplets radius and surface static contact angle. • Optimum conditions are for droplets with radius 35–40 μm and contact angle near 160°. • Jumping phenomenon occurs only when static contact angle is above 140°. • The optimal functional surface design maximises jumping velocity and heat flux. - Abstract: Dropwise condensation has superior heat transfer efficiency than filmwise condensation; however condensate evacuation from the surface still remains a significant technological challenge. The process of droplets jumping, against adhesive forces, from a solid surface upon coalescence has been studied using both experimental and Computational Fluid Dynamics (CFD) analysis. Both Lattice Boltzmann (LBM) and Volume of Fluid (VOF) methods have been used to evaluate different kinematic conditions of coalescence inducing a jump velocity. In this paper, an optimisation framework for superhydrophobic surface designs is presented which uses experimentally verified high fidelity CFD analyses to identify optimal combinations of design features which maximise desirable characteristics such as the vertical velocity of the merged jumping droplet from the surface and energy efficiency. A Radial Basis Function (RBF)-based surrogate modelling approach using Design of Experiment (DOE) technique was used to establish near-optimal initial process parameters around which to focus the study. This multidisciplinary approach allows us to evaluate the jumping phenomenon for superhydrophobic surfaces for which several input parameters may be varied, so as to improve the heat transfer exchange rate on the surface during condensation. Reliable conditions were found to occur for droplets within initial radius range of r = 20–40 μm and static contact angle θ_s ∼ 160°. Moreover, the jumping phenomenon was observed for droplets with initial

  18. Developments of a bonding technique for optical materials by a surface activation method

    International Nuclear Information System (INIS)

    Sugiyama, Akira; Oda, Tomohiro; Abe, Tomoyuki; Kusunoki, Isao

    2007-01-01

    We have been developing a pair of sample holder used for optics in the surface activation bonding equipment. The holder can adjust the relative position of samples in the order of sub mm. To study the degree of dislocation appearing crystal surface activated by a fast atomic beam, irradiated sapphire crystals were examined by RBS, XPS, and AFM analysis. The heat treatment recovered the surface roughness of irradiated sapphire when the heating temperature reached at 1573 K. (author)

  19. Surface-Activated Amorphous Alloy Fuel Electrodes for Methanol Fuel Cell

    OpenAIRE

    Asahi, Kawashima; Koji, Hashimoto; The Research Institute for Iron, Steel and Other Metals; The Research Institute for Iron, Steel and Other Metals

    1983-01-01

    Amorphous alloy electrodes for electrochemical oxidation of methanol and its derivatives were obtained by the surface activation treatment consisting of electrodeposition of zinc on as-quenched amorphous alloy substrates, heating at 200-300℃ for 30 min, and subsequently leaching of zinc in an alkaline solution. The surface activation treatment provided a new method for the preparation of a large surface area on the amorphous alloys. The best result for oxidation of methanol, sodium formate an...

  20. Selective metallization of polymers using laser induced surface activation (LISA)—characterization and optimization of porous surface topography

    DEFF Research Database (Denmark)

    Zhang, Yang; Hansen, Hans Nørgaard; De Grave, Arnaud

    2011-01-01

    Laser induced selective activation (LISA) is a molded interconnected devices technique for selective metallization of polymers. On the working piece, only the laser-machined area can be metalized in the subsequent plating. The principle of the technology is introduced. Surface analysis was perfor...

  1. Functionalized granular activated carbon and surface complexation with chromates and bi-chromates in wastewater

    Energy Technology Data Exchange (ETDEWEB)

    Singha, Somdutta; Sarkar, Ujjaini, E-mail: usarkar@chemical.jdvu.ac.in; Luharuka, Pallavi

    2013-03-01

    Cr(VI) is present in the aqueous medium as chromate (CrO{sub 4}{sup 2−}) and bi-chromate (HCrO{sub 4}{sup −}). Functionalized granular activated carbons (FACs) are used as adsorbents in the treatment of wastewaters containing hexavalent chromium. The FACs are prepared by chemical modifications of granular activated carbons (GACs) using functionalizing agents like HNO{sub 3}, HCl and HF. The Brunauer, Emmett and Teller surface areas of FAC-HCl (693.5 m{sup 2}/g), FAC-HNO{sub 3} (648.8 m{sup 2}/g) and FAC-HF (726.2 m{sup 2}/g) are comparable to the GAC (777.7 m{sup 2}/g). But, the adsorption capacity of each of the FAC-HNO{sub 3}, FAC-HCl and FAC-HF is found to be higher than the GAC. The functional groups play an important role in the adsorption process and pH has practically no role in this specific case. The FACs have hydrophilic protonated external surfaces in particular, along with the functional surface sites capable to make complexes with the CrO{sub 4}{sup 2−} and HCrO{sub 4}{sup −} present. Surface complex formation is maximized in the order FAC-HNO{sub 3} > FAC-HF > FAC-HCl, in proportion to the total surface acidity. This is also confirmed by the well-known pseudo second-order kinetic model. Physi-sorption equilibrium isotherms are parameterized by using standard Freundlich and Langmuir models. Langmuir fits better. The formation of surface complexes with the functional groups and hexavalent chromium is also revealed in the images of field emission scanning electron micrograph; energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy analysis after adsorption. The intra-particle diffusion is not the only rate-controlling factor. The Boyd's film diffusion model fits very well with R{sup 2} as high as 98.1% for FAC-HNO{sub 3}. This result demonstrates that the functionalization of the GAC by acid treatments would increase the diffusion rate, predominantly with a boundary layer diffusion effect. - Highlights: ► Physico

  2. EarthShape: A Strategy for Investigating the Role of Biota on Surface Processes

    Science.gov (United States)

    Übernickel, Kirstin; Ehlers, Todd Alan; von Blanckenburg, Friedhelm; Paulino, Leandro

    2017-04-01

    EarthShape - "Earth surface shaping by biota" is a 6-year priority research program funded by the German science foundation (DFG-SPP 1803) that performs soil- and landscape-scale critical zone research at 4 locations along a climate gradient in Chile, South America. The program is in its first year and involves an interdisciplinary collaboration between geologists, geomorphologists, ecologists, soil scientists, microbiologists, geophysicists, geochemists, hydrogeologists and climatologists including 18 German and 8 Chilean institutions. EarthShape is composed of 4 research clusters representing the process chain from weathering of substrate to deposition of eroded material. Cluster 1 explores micro-biota as the "weathering engine". Investigations in this cluster quantify different mechanisms of biogenic weathering whereby plants, fungi, and bacteria interact with rock in the production of soil. Cluster 2 explores bio-mediated redistribution of material within the weathering zone. Studies in this cluster focus on soil catenas along hill slope profiles to investigate the modification of matter along its transport path. Cluster 3 explores biotic modulation of erosion and sediment routing at the catchment scale. Investigations in this cluster explore the effects of vegetation cover on solute and sediment transport from hill slopes to the channel network. Cluster 4 explores the depositional legacy of coupled biogenic and Earth surface systems. This cluster investigates records of vegetation-land surface interactions in different depositional settings. A final component of EarthShape lies in the integration of results from these 4 clusters using numerical models to bridging between the diverse times scales used by different disciplines. The Chilean Coastal Cordillera between 25° and 40°S was selected to carry out this research because its north-south orientation captures a large ecological and climate gradient. This gradient ranges from hyper-arid (Atacama desert) to

  3. Defluoridation of water using activated alumina in presence of natural organic matter via response surface methodology.

    Science.gov (United States)

    Samarghandi, Mohammad Reza; Khiadani, Mehdi; Foroughi, Maryam; Zolghadr Nasab, Hasan

    2016-01-01

    Adsorption by activated alumina is considered to be one of the most practiced methods for defluoridation of freshwater. This study was conducted, therefore, to investigate the effect of natural organic matters (NOMs) on the removal of fluoride by activated alumina using response surface methodology. To the authors' knowledge, this has not been previously investigated. Physico-chemical characterization of the alumina was determined by scanning electron microscope (SEM), Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF), and X-ray diffractometer (XRD). Response surface methodology (RSM) was applied to evaluate the effect of single and combined parameters on the independent variables such as the initial concentration of fluoride, NOMs, and pH on the process. The results revealed that while presence of NOM and increase of pH enhance fluoride adsorption on the activated alumina, initial concentration of fluoride has an adverse effect on the efficiency. The experimental data were analyzed and found to be accurately and reliably fitted to a second-order polynomial model. Under optimum removal condition (fluoride concentration 20 mg/L, NOM concentration 20 mg/L, and pH 7) with a desirability value of 0.93 and fluoride removal efficiency of 80.6%, no significant difference was noticed with the previously reported sequence of the co-exiting ion affinity to activated alumina for fluoride removal. Moreover, aluminum residual was found to be below the recommended value by the guideline for drinking water. Also, the increase of fluoride adsorption on the activated alumina, as NOM concentrations increase, could be due to the complexation between fluoride and adsorbed NOM. Graphical abstract ᅟ.

  4. Dual brush process for selective surface modification in graphoepitaxy directed self-assembly

    Science.gov (United States)

    Doise, Jan; Chan, Boon Teik; Hori, Masafumi; Gronheid, Roel

    2017-07-01

    Graphoepitaxy directed self-assembly is a potential low-cost solution for patterning via layers with pitches beyond the reach of a single optical lithographic exposure. In this process, selective control of the interfacial energy at the bottom and sidewall of the template is an important but challenging exercise. A dual brush process is implemented, in which two brushes with distinct end-groups are consecutively grafted to the prepattern to achieve fully independent modification of the bottom and sidewall surface of the template. A comprehensive study of hole pattern quality shows that using a dual brush process leads to a substantial improvement in terms of positional and dimensional variability across the process window. These findings will be useful to others who wish to manipulate polymer-surface interactions in directed self-assembly flows.

  5. Polyphosphate nanoparticles on the platelet surface trigger contact system activation

    NARCIS (Netherlands)

    Verhoef, Johan J F; Barendrecht, Arjan D; Nickel, Katrin F; Dijkxhoorn, Kim; Kenne, Ellinor; Labberton, Linda; McCarty, Owen J T; Schiffelers, Raymond; Heijnen, Harry F G; Hendrickx, Antoni P A; Schellekens, Huub; Fens, Marcel H; de Maat, Steven; Renné, Thomas; Maas, Coen

    2017-01-01

    Polyphosphate is an inorganic polymer that can potentiate several interactions in the blood coagulation system. Blood platelets contain polyphosphate, and the secretion of platelet-derived polyphosphate has been associated with increased thrombus formation and activation of coagulation factor XII.

  6. Surface plasmon polariton modulator with optimized active layer

    DEFF Research Database (Denmark)

    Babicheva, Viktoriia; Lavrinenko, Andrei

    2012-01-01

    package CST Microwave Studio in the frequency domain. We explore different permittivities of the ITO layer, which can be achieved by utilizing different anneal conditions. To increase transmittance and enhance modulation depth or efficiency, we propose to pattern the continuous active layer. Dependence...... from the pattern size and filling factor of the active material are analyzed for tuned permittivity of the ITO layer. Direct simulation of the device functionality validates optimization design....

  7. Advanced measurement and analysis of surface textures produced by micro-machining processes

    International Nuclear Information System (INIS)

    Bordatchev, Evgueni V; Hafiz, Abdullah M K

    2014-01-01

    Surface texture of a part or a product has significant effects on its functionality, physical-mechanical properties and visual appearance. In particular for miniature products, the implication of surface quality becomes critical owing to the presence of geometrical features with micro/nano-scale dimensions. Qualitative and quantitative assessments of surface texture are carried out predominantly by profile parameters, which are often insufficient to address the contribution of constituent spatial components with varied amplitudes and wavelengths. In this context, this article presents a novel approach for advanced measurement and analysis of profile average roughness (R a ) and its spatial distribution at different wavelength intervals. The applicability of the proposed approach was verified for three different surface topographies prepared by grinding, laser micro-polishing and micro-milling processes. From the measurement and analysis results, R a (λ) spatial distribution was found to be an effective measure of revealing the contributions of various spatial components within specific wavelength intervals towards formation of the entire surface profile. In addition, the approach was extended to the measurement and analysis of areal average roughness S a (λ) spatial distribution within different wavelength intervals. Besides, the proposed method was demonstrated to be a useful technique in developing a functional correlation between a manufacturing process and its corresponding surface profile. (paper)

  8. Making waves: Kinetic processes controlling surface evolution during low energy ion sputtering

    International Nuclear Information System (INIS)

    Chan, W.L.; Chason, Eric

    2007-01-01

    When collimated beams of low energy ions are used to bombard materials, the surface often develops a periodic pattern or ''ripple'' structure. Different types of patterns are observed to develop under different conditions, with characteristic features that depend on the substrate material, the ion beam parameters, and the processing conditions. Because the patterns develop spontaneously, without applying any external mask or template, their formation is the expression of a dynamic balance among fundamental surface kinetic processes, e.g., erosion of material from the surface, ion-induced defect creation, and defect-mediated evolution of the surface morphology. In recent years, a comprehensive picture of the different kinetic mechanisms that control the different types of patterns that form has begun to emerge. In this article, we provide a review of different mechanisms that have been proposed and how they fit together in terms of the kinetic regimes in which they dominate. These are grouped into regions of behavior dominated by the directionality of the ion beam, the crystallinity of the surface, the barriers to surface roughening, and nonlinear effects. In sections devoted to each type of behavior, we relate experimental observations of patterning in these regimes to predictions of continuum models and to computer simulations. A comparison between theory and experiment is used to highlight strengths and weaknesses in our understanding. We also discuss the patterning behavior that falls outside the scope of the current understanding and opportunities for advancement

  9. Enhanced 3D face processing using an active vision system

    DEFF Research Database (Denmark)

    Lidegaard, Morten; Larsen, Rasmus; Kraft, Dirk

    2014-01-01

    We present an active face processing system based on 3D shape information extracted by means of stereo information. We use two sets of stereo cameras with different field of views (FOV): One with a wide FOV is used for face tracking, while the other with a narrow FOV is used for face identification...

  10. Process cells dismantling of EUREX pant: previous activities

    International Nuclear Information System (INIS)

    Gili, M.

    1998-01-01

    In the '98-'99 period some process cells of the EUREX pant will be dismantled, in order to place there the liquid wastes conditioning plant 'CORA'. This report resumes the previous activities (plant rinsing campaigns and inactive Cell 014 dismantling), run in the past three years and the drawn experience [it