Surface topography of 1€ coin measured by stereo-PIXE

NASA Astrophysics Data System (ADS)

Gholami-Hatam, E.; Lamehi-Rachti, M.; Vavpetič, P.; Grlj, N.; Pelicon, P.

2013-07-01

We demonstrate the stereo-PIXE method by measurement of surface topography of the relief details on 1€ coin. Two X-ray elemental maps were simultaneously recorded by two X-ray detectors positioned at the left and the right side of the proton microbeam. The asymmetry of the yields in the pixels of the two X-ray maps occurs due to different photon attenuation on the exit travel path of the characteristic X-rays from the point of emission through the sample into the X-ray detectors. In order to calibrate the inclination angle with respect to the X-ray asymmetry, a flat inclined surface model was at first applied for the sample in which the matrix composition and the depth elemental concentration profile is known. After that, the yield asymmetry in each image pixel was transferred into corresponding local inclination angle using calculated dependence of the asymmetry on the surface inclination. Finally, the quantitative topography profile was revealed by integrating the local inclination angle over the lateral displacement of the probing beam.

Bioceramic coating of hydroxyapatite fabricated on Ti-6Al-4V with Nd-YAG laser

NASA Astrophysics Data System (ADS)

Tlotleng, Monnamme; Akinlabi, Esther T.; Shukla, Mukul; Pityana, Sisa

2015-03-01

This paper presents on the direct laser melted hydroxyapatite coatings achieved by melting the pre-placed powder beds using Nd-YAG laser. The process development and optimized parameters are reported. The results show that by changing the laser power and the beam inclined plane it is possible that a desirable coating of HAP that is rich on the surface can be produced. The microstructures of the coatings showed balling and cracking at beam angles between 0-15° and at 27° a successful coating was achieved with laser power and scanning speed of 750W and 5mm/s respectively. The said coating was pore and crack free while it retained non-decomposed HAP crystallites on the surface (mixed). The microstructure of the transition layer concluded a moderate temperature process since the formed dendrites did not develop or form secondary arms. The Ca/P conducted on the coating using EDS concluded Ca/P ratio of 8.04 and the absence of titanium phosphates phase (TiP2). TiP2 is typically associated with the decomposition of HAP and indicate the presence of high processing temperatures. Even so, the current results indicated that the investigated process was successful in depositing HAP coating with desirable microstructures even though its bio-corrosion properties still need to be ascertained before it could be qualified as suitable for biomedical applications.

Influence of Surface Properties and Impact Conditions on Adhesion of Insect Residues

NASA Technical Reports Server (NTRS)

Wohl, Christopher J.; Smith, Joseph G.; Connell, John W.; Siochi, Emilie J.; Doss, Jereme R.; Shanahan, Michelle H.; Penner, Ronald K.

2015-01-01

Insect residues can cause premature transition to turbulent flow on laminar flow airfoils. Engineered surfaces that mitigate the adhesion of insect residues provide, therefore, a route to more efficient aerodynamics and reduced fuel burn rates. Areal coverage and heights of residues depend not only on surface properties, but also on impact conditions. We report high speed photography of fruit fly impacts at different angles of inclination on a rigid aluminum surface, optical microscopy and profilometry, and contact angle goniometry to support the design of engineered surfaces. For the polyurethane and epoxy coatings studied, some of which exhibited superhydrophobicity, it was determined that impact angle and surface compositions play critical roles in the efficacy of these surfaces to reduce insect residue adhesion.

Reconstruction of inclined air showers detected with the Pierre Auger Observatory

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

Collaboration: Pierre Auger Collaboration

2014-08-01

We describe the method devised to reconstruct inclined cosmic-ray air showers with zenith angles greater than 60° detected with the surface array of the Pierre Auger Observatory. The measured signals at the ground level are fitted to muon density distributions predicted with atmospheric cascade models to obtain the relative shower size as an overall normalization parameter. The method is evaluated using simulated showers to test its performance. The energy of the cosmic rays is calibrated using a sub-sample of events reconstructed with both the fluorescence and surface array techniques. The reconstruction method described here provides the basis of complementary analysesmore » including an independent measurement of the energy spectrum of ultra-high energy cosmic rays using very inclined events collected by the Pierre Auger Observatory.« less

Reconstruction of inclined air showers detected with the Pierre Auger Observatory

NASA Astrophysics Data System (ADS)

Pierre Auger Collaboration; Aab, A.; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Samarai, I. Al; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Alves Batista, R.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Aramo, C.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Badescu, A. M.; Barber, K. B.; Bäuml, J.; Baus, C.; Beatty, J. J.; Becker, K. H.; Bellido, J. A.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Boháčová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Collica, L.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cooper, M. J.; Coutu, S.; Covault, C. E.; Criss, A.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; de Jong, S. J.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; D\\'\\iaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; Dorosti Hasankiadeh, Q.; Dova, M. T.; Ebr, J.; Engel, R.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fernandes, M.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipčič, A.; Fox, B. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Fuji, T.; Gaior, R.; Garc\\'\\ia, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gate, F.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Giller, M.; Glaser, C.; Glass, H.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gorham, P.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Hansen, P.; Harari, D.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hörandel, J. R.; Horvath, P.; Hrabovský, M.; Huber, D.; Huege, T.; Insolia, A.; Isar, P. G.; Islo, K.; Jandt, I.; Jansen, S.; Jarne, C.; Josebachuili, M.; Kääpä, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Krause, R.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuempel, D.; Kunka, N.; La Rosa, G.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agëra, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Malacari, M.; Maldera, S.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Mariş, I. C.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Mart\\'\\inez Bravo, O.; Martraire, D.; Mas\\'\\ias Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, A. J.; Matthews, J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Mićanović, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morello, C.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Newton, D.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nožka, L.; Ochilo, L.; Olinto, A.; Oliveira, M.; Olmos-Gilbaja, V. M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Papenbreer, P.; Parente, G.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Pȩkala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Peters, C.; Petrera, S.; Petrolini, A.; Petrov, Y.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porcelli, A.; Porowski, C.; Privitera, P.; Prouza, M.; Purrello, V.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenu, B.; Ridky, J.; Riggi, S.; Risse, M.; Ristori, P.; Rizi, V.; Roberts, J.; Rodrigues de Carvalho, W.; Rodriguez Cabo, I.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Rodr\\'\\iguez-Fr\\'\\ias, M. D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Roulet, E.; Rovero, A. C.; Rühle, C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Salesa Greus, F.; Salina, G.; Sánchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Scholten, O.; Schoorlemmer, H.; Schovánek, P.; Schulz, A.; Schulz, J.; Sciutto, S. J.; Segreto, A.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Śmiał kowski, A.; Šm\\'\\ida, R.; Snow, G. R.; Sommers, P.; Sorokin, J.; Squartini, R.; Srivastava, Y. N.; Stanič, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Stutz, A.; Suarez, F.; Suomijärvi, T.; Supanitsky, A. D.; Sutherland, M. S.; Swain, J.; Szadkowski, Z.; Szuba, M.; Taborda, O. A.; Tapia, A.; Tartare, M.; Thao, N. T.; Theodoro, V. M.; Tiffenberg, J.; Timmermans, C.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tomé, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Trovato, E.; Tueros, M.; Ulrich, R.; Unger, M.; Urban, M.; Valdés Galicia, J. F.; Valiño, I.; Valore, L.; van Aar, G.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cárdenas, B.; Varner, G.; Vázquez, J. R.; Vázquez, R. A.; Veberič, D.; Verzi, V.; Vicha, J.; Videla, M.; Villaseñor, L.; Vlcek, B.; Vorobiov, S.; Wahlberg, H.; Wainberg, O.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Whelan, B. J.; Widom, A.; Wiencke, L.; Wilczyńska, B.; Wilczyński, H.; Will, M.; Williams, C.; Winchen, T.; Wittkowski, D.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Younk, P.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zaw, I.; Zepeda, A.; Zhou, J.; Zhu, Y.; Zimbres Silva, M.; Ziolkowski, M.

2014-08-01

We describe the method devised to reconstruct inclined cosmic-ray air showers with zenith angles greater than 60° detected with the surface array of the Pierre Auger Observatory. The measured signals at the ground level are fitted to muon density distributions predicted with atmospheric cascade models to obtain the relative shower size as an overall normalization parameter. The method is evaluated using simulated showers to test its performance. The energy of the cosmic rays is calibrated using a sub-sample of events reconstructed with both the fluorescence and surface array techniques. The reconstruction method described here provides the basis of complementary analyses including an independent measurement of the energy spectrum of ultra-high energy cosmic rays using very inclined events collected by the Pierre Auger Observatory.

Insulator coating for high temperature alloys method for producing insulator coating for high temperature alloys

DOEpatents

Park, J.H.

1998-06-23

A method for fabricating an electrically insulating coating on a surface is disclosed comprising coating the surface with a metal, and reacting the metal coated surface with a nonmetal so as to create a film on the metal-coated surface. Alternatively, the invention provides for a method for producing a noncorrosive, electrically insulating coating on a surface saturated with a nonmetal comprising supplying a molten fluid, dissolving a metal in the molten fluid to create a mixture, and contacting the mixture with the saturated surface. Lastly, the invention provides an electrically insulative coating comprising an underlying structural substrate coated with an oxide or nitride compound. 2 figs.

On crack growth in molar teeth from contact on the inclined occlusal surface.

PubMed

Chai, Herzl

2015-04-01

Extracted human molar teeth are indented by hard balls laid at the central fossa, sectioned, and their interior examined for damage. Contact on the fissured enamel coat generally occurs on three distinct spots. The main forms of damage are radial cracks growing from the DEJ to the occlusal surface and median radial and cylindrical cracks growing from a contact spot to the DEJ. For large balls failure by edge chipping near a cusp apex may occur. The median cracks tend to run unstably to the DEJ upon reaching the middle part of the enamel coat. The corresponding load, PFM, and the load needed to initiate radial cracks at the DEJ, PFR, are taken to signal crown failure. The mean values of PFM and PFR are on the order of 1000N. A conical bilayer model defined by thickness d, inclination angle θ, failure stress σF and toughness KC of the enamel coat is developed to assess crown failure. The analytical predictions for PFR and PFM agree well with the tests. The results indicate that enamel thickness is so designed as to ensure that PFR and PFM just exceed the maximum bite force under normal conditions while the choice of θ seems to reflect a compromise between needs to resist crown failure and break hard food particles. Both PFR and PFM are greatly reduced with reducing d, which points to the danger posed by tooth wear. The analytical expressions for PFR and PFM may also apply to other multi-cusp mammalian or prosthetic molar crowns. Cone cracking, suppressed in the anisotropic tooth enamel, may be an important failure mode in prosthetic crowns. Copyright © 2014 Elsevier Ltd. All rights reserved.

Radiographic evaluation of BFX acetabular component position in dogs.

PubMed

Renwick, Alasdair; Gemmill, Toby; Pink, Jonathan; Brodbelt, David; McKee, Malcolm

2011-07-01

To assess the reliability of radiographic measurement of angle of lateral opening (ALO) and angle of version of BFX acetabular cups. In vitro radiographic study. BFX cups (24, 28, and 32 mm). Total hip replacement constructs (cups, 17 mm femoral head and a #7 CFX stem) were mounted on an inclinometer. Ventrodorsal radiographs were obtained with ALO varying between 21° and 70° and inclination set at 0°, 10°, 20°, and 30°. Radiographs were randomized using a random sequence generator. Three observers blinded to the radiograph order assessed ALO using 3 methods: (1) an ellipse method based on trigonometry; (2) using a measurement from the center of the femoral head to the truncated surface of the cup; (3) by visual estimation using a reference chart. Version was measured by assessing the ventral edge of the truncated surface. ALO methods 2 and 3 were accurate and precise to within 10° and were significantly more accurate and precise than method 1 (P < .001). All methods were significantly less accurate with increasing inclination. Version measurement was accurate and precise to within 7° with 0-20° of inclination, but significantly less accurate with 30° of inclination. Methods 2 and 3, but not method 1, were sufficiently accurate and precise to be clinically useful. Version measurement was clinically useful when inclination was ≤ 20°. © Copyright 2011 by The American College of Veterinary Surgeons.

Analysis and design of wedge projection display system based on ray retracing method.

PubMed

Lee, Chang-Kun; Lee, Taewon; Sung, Hyunsik; Min, Sung-Wook

2013-06-10

A design method for the wedge projection display system based on the ray retracing method is proposed. To analyze the principle of image formation on the inclined surface of the wedge-shaped waveguide, the bundle of rays is retraced from an imaging point on the inclined surface to the aperture of the waveguide. In consequence of ray retracing, we obtain the incident conditions of the ray, such as the position and the angle at the aperture, which provide clues for image formation. To illuminate the image formation, the concept of the equivalent imaging point is proposed, which is the intersection where the incident rays are extended over the space regardless of the refraction and reflection in the waveguide. Since the initial value of the rays arriving at the equivalent imaging point corresponds to that of the rays converging into the imaging point on the inclined surface, the image formation can be visualized by calculating the equivalent imaging point over the entire inclined surface. Then, we can find image characteristics, such as their size and position, and their degree of blur--by analyzing the distribution of the equivalent imaging point--and design the optimized wedge projection system by attaching the prism structure at the aperture. The simulation results show the feasibility of the ray retracing analysis and characterize the numerical relation between the waveguide parameters and the aperture structure for on-axis configuration. The experimental results verify the designed system based on the proposed method.

Method for smoothing the surface of a protective coating

DOEpatents

Sangeeta, D.; Johnson, Curtis Alan; Nelson, Warren Arthur

2001-01-01

A method for smoothing the surface of a ceramic-based protective coating which exhibits roughness is disclosed. The method includes the steps of applying a ceramic-based slurry or gel coating to the protective coating surface; heating the slurry/gel coating to remove volatile material; and then further heating the slurry/gel coating to cure the coating and bond it to the underlying protective coating. The slurry/gel coating is often based on yttria-stabilized zirconia, and precursors of an oxide matrix. Related articles of manufacture are also described.

Innovations in coating technology.

PubMed

Behzadi, Sharareh S; Toegel, Stefan; Viernstein, Helmut

2008-01-01

Despite representing one of the oldest pharmaceutical techniques, coating of dosage forms is still frequently used in pharmaceutical manufacturing. The aims of coating range from simply masking the taste or odour of drugs to the sophisticated controlling of site and rate of drug release. The high expectations for different coating technologies have required great efforts regarding the development of reproducible and controllable production processes. Basically, improvements in coating methods have focused on particle movement, spraying systems, and air and energy transport. Thereby, homogeneous distribution of coating material and increased drying efficiency should be accomplished in order to achieve high end product quality. Moreover, given the claim of the FDA to design the end product quality already during the manufacturing process (Quality by Design), the development of analytical methods for the analysis, management and control of coating processes has attracted special attention during recent years. The present review focuses on recent patents claiming improvements in pharmaceutical coating technology and intends to first familiarize the reader with the available procedures and to subsequently explain the application of different analytical tools. Aiming to structure this comprehensive field, coating technologies are primarily divided into pan and fluidized bed coating methods. Regarding pan coating procedures, pans rotating around inclined, horizontal and vertical axes are reviewed separately. On the other hand, fluidized bed technologies are subdivided into those involving fluidized and spouted beds. Then, continuous processing techniques and improvements in spraying systems are discussed in dedicated chapters. Finally, currently used analytical methods for the understanding and management of coating processes are reviewed in detail in the last section of the review.

UV photofunctionalization promotes nano-biomimetic apatite deposition on titanium

PubMed Central

Saita, Makiko; Ikeda, Takayuki; Yamada, Masahiro; Kimoto, Katsuhiko; Lee, Masaichi Chang-Il; Ogawa, Takahiro

2016-01-01

Background Although biomimetic apatite coating is a promising way to provide titanium with osteoconductivity, the efficiency and quality of deposition is often poor. Most titanium implants have microscale surface morphology, and an addition of nanoscale features while preserving the micromorphology may provide further biological benefit. Here, we examined the effect of ultraviolet (UV) light treatment of titanium, or photofunctionalization, on the efficacy of biomimetic apatite deposition on titanium and its biological capability. Methods and results Micro-roughed titanium disks were prepared by acid-etching with sulfuric acid. Micro-roughened disks with or without photofunctionalization (20-minute exposure to UV light) were immersed in simulated body fluid (SBF) for 1 or 5 days. Photofunctionalized titanium disks were superhydrophilic and did not form surface air bubbles when immersed in SBF, whereas non-photofunctionalized disks were hydrophobic and largely covered with air bubbles during immersion. An apatite-related signal was observed by X-ray diffraction on photofunctionalized titanium after 1 day of SBF immersion, which was equivalent to the one observed after 5 days of immersion of control titanium. Scanning electron microscopy revealed nodular apatite deposition in the valleys and at the inclines of micro-roughened structures without affecting the existing micro-configuration. Micro-roughened titanium and apatite-deposited titanium surfaces had similar roughness values. The attachment, spreading, settling, proliferation, and alkaline phosphate activity of bone marrow-derived osteoblasts were promoted on apatite-coated titanium with photofunctionalization. Conclusion UV-photofunctionalization of titanium enabled faster deposition of nanoscale biomimetic apatite, resulting in the improved biological capability compared to the similarly prepared apatite-deposited titanium without photofunctionalization. Photofunctionalization-assisted biomimetic apatite deposition may be a novel method to effectively enhance micro-roughened titanium surfaces without altering their microscale morphology. PMID:26834469

Corrosion prevention of magnesium surfaces via surface conversion treatments using ionic liquids

DOEpatents

Qu, Jun; Luo, Huimin

2016-09-06

A method for conversion coating a magnesium-containing surface, the method comprising contacting the magnesium-containing surface with an ionic liquid compound under conditions that result in decomposition of the ionic liquid compound to produce a conversion coated magnesium-containing surface having a substantially improved corrosion resistance relative to the magnesium-containing surface before said conversion coating. Also described are the resulting conversion-coated magnesium-containing surface, as well as mechanical components and devices containing the conversion-coated magnesium-containing surface.

Prediction of forces and moments for hypersonic flight vehicle control effectors

NASA Technical Reports Server (NTRS)

Maughmer, Mark D.; Long, Lyle N.; Guilmette, Neal; Pagano, Peter

1993-01-01

This research project includes three distinct phases. For completeness, all three phases of the work are briefly described in this report. The goal was to develop methods of predicting flight control forces and moments for hypersonic vehicles which could be used in a preliminary design environment. The first phase included a preliminary assessment of subsonic/supersonic panel methods and hypersonic local flow inclination methods for such predictions. While these findings clearly indicated the usefulness of such methods for conceptual design activities, deficiencies exist in some areas. Thus, a second phase of research was conducted in which a better understanding was sought for the reasons behind the successes and failures of the methods considered, particularly for the cases at hypersonic Mach numbers. This second phase involved using computational fluid dynamics methods to examine the flow fields in detail. Through these detailed predictions, the deficiencies in the simple surface inclination methods were determined. In the third phase of this work, an improvement to the surface inclination methods was developed. This used a novel method for including viscous effects by modifying the geometry to include the viscous/shock layer.

Influence of Initial Inclined Surface Crack on Estimated Residual Fatigue Lifetime of Railway Axle

NASA Astrophysics Data System (ADS)

Náhlík, Luboš; Pokorný, Pavel; Ševčík, Martin; Hutař, Pavel

2016-11-01

Railway axles are subjected to cyclic loading which can lead to fatigue failure. For safe operation of railway axles a damage tolerance approach taking into account a possible defect on railway axle surface is often required. The contribution deals with an estimation of residual fatigue lifetime of railway axle with initial inclined surface crack. 3D numerical model of inclined semi-elliptical surface crack in railway axle was developed and its curved propagation through the axle was simulated by finite element method. Presence of press-fitted wheel in the vicinity of initial crack was taken into account. A typical loading spectrum of railway axle was considered and residual fatigue lifetime was estimated by NASGRO approach. Material properties of typical axle steel EA4T were considered in numerical calculations and lifetime estimation.

Effects of Surface Inclination on the Vertical Loading Rates and Landing Pattern during the First Attempt of Barefoot Running in Habitual Shod Runners.

PubMed

An, W; Rainbow, M J; Cheung, R T H

2015-01-01

Barefoot running has been proposed to reduce vertical loading rates, which is a risk factor of running injuries. Most of the previous studies evaluated runners on level surfaces. This study examined the effect of surface inclination on vertical loading rates and landing pattern during the first attempt of barefoot running among habitual shod runners. Twenty habitual shod runners were asked to run on treadmill at 8.0 km/h at three inclination angles (0°; +10°; -10°) with and without their usual running shoes. Vertical average rate (VALR) and instantaneous loading rate (VILR) were obtained by established methods. Landing pattern was decided using high-speed camera. VALR and VILR in shod condition were significantly higher (p < 0.001) in declined than in level or inclined treadmill running, but not in barefoot condition (p > 0.382). There was no difference (p > 0.413) in the landing pattern among all surface inclinations. Only one runner demonstrated complete transition to non-heel strike landing in all slope conditions. Reducing heel strike ratio in barefoot running did not ensure a decrease in loading rates (p > 0.15). Conversely, non-heel strike landing, regardless of footwear condition, would result in a softer landing (p < 0.011).

Effects of Surface Inclination on the Vertical Loading Rates and Landing Pattern during the First Attempt of Barefoot Running in Habitual Shod Runners

PubMed Central

An, W.; Rainbow, M. J.; Cheung, R. T. H.

2015-01-01

Barefoot running has been proposed to reduce vertical loading rates, which is a risk factor of running injuries. Most of the previous studies evaluated runners on level surfaces. This study examined the effect of surface inclination on vertical loading rates and landing pattern during the first attempt of barefoot running among habitual shod runners. Twenty habitual shod runners were asked to run on treadmill at 8.0 km/h at three inclination angles (0°; +10°; −10°) with and without their usual running shoes. Vertical average rate (VALR) and instantaneous loading rate (VILR) were obtained by established methods. Landing pattern was decided using high-speed camera. VALR and VILR in shod condition were significantly higher (p < 0.001) in declined than in level or inclined treadmill running, but not in barefoot condition (p > 0.382). There was no difference (p > 0.413) in the landing pattern among all surface inclinations. Only one runner demonstrated complete transition to non-heel strike landing in all slope conditions. Reducing heel strike ratio in barefoot running did not ensure a decrease in loading rates (p > 0.15). Conversely, non-heel strike landing, regardless of footwear condition, would result in a softer landing (p < 0.011). PMID:26258133

Slip resistance of winter footwear on snow and ice measured using maximum achievable incline.

PubMed

Hsu, Jennifer; Shaw, Robert; Novak, Alison; Li, Yue; Ormerod, Marcus; Newton, Rita; Dutta, Tilak; Fernie, Geoff

2016-05-01

Protective footwear is necessary for preventing injurious slips and falls in winter conditions. Valid methods for assessing footwear slip resistance on winter surfaces are needed in order to evaluate footwear and outsole designs. The purpose of this study was to utilise a method of testing winter footwear that was ecologically valid in terms of involving actual human testers walking on realistic winter surfaces to produce objective measures of slip resistance. During the experiment, eight participants tested six styles of footwear on wet ice, on dry ice, and on dry ice after walking over soft snow. Slip resistance was measured by determining the maximum incline angles participants were able to walk up and down in each footwear-surface combination. The results indicated that testing on a variety of surfaces is necessary for establishing winter footwear performance and that standard mechanical bench tests for footwear slip resistance do not adequately reflect actual performance. Practitioner Summary: Existing standardised methods for measuring footwear slip resistance lack validation on winter surfaces. By determining the maximum inclines participants could walk up and down slopes of wet ice, dry ice, and ice with snow, in a range of footwear, an ecologically valid test for measuring winter footwear performance was established.

Slip resistance of winter footwear on snow and ice measured using maximum achievable incline

PubMed Central

Hsu, Jennifer; Shaw, Robert; Novak, Alison; Li, Yue; Ormerod, Marcus; Newton, Rita; Dutta, Tilak; Fernie, Geoff

2016-01-01

Abstract Protective footwear is necessary for preventing injurious slips and falls in winter conditions. Valid methods for assessing footwear slip resistance on winter surfaces are needed in order to evaluate footwear and outsole designs. The purpose of this study was to utilise a method of testing winter footwear that was ecologically valid in terms of involving actual human testers walking on realistic winter surfaces to produce objective measures of slip resistance. During the experiment, eight participants tested six styles of footwear on wet ice, on dry ice, and on dry ice after walking over soft snow. Slip resistance was measured by determining the maximum incline angles participants were able to walk up and down in each footwear–surface combination. The results indicated that testing on a variety of surfaces is necessary for establishing winter footwear performance and that standard mechanical bench tests for footwear slip resistance do not adequately reflect actual performance. Practitioner Summary: Existing standardised methods for measuring footwear slip resistance lack validation on winter surfaces. By determining the maximum inclines participants could walk up and down slopes of wet ice, dry ice, and ice with snow, in a range of footwear, an ecologically valid test for measuring winter footwear performance was established. PMID:26555738

Monte Carlo calculation model for heat radiation of inclined cylindrical flames and its application

NASA Astrophysics Data System (ADS)

Chang, Zhangyu; Ji, Jingwei; Huang, Yuankai; Wang, Zhiyi; Li, Qingjie

2017-07-01

Based on Monte Carlo method, a calculation model and its C++ calculating program for radiant heat transfer from an inclined cylindrical flame are proposed. In this model, the total radiation energy of the inclined cylindrical flame is distributed equally among a certain number of energy beams, which are emitted randomly from the flame surface. The incident heat flux on a surface is calculated by counting the number of energy beams which could reach the surface. The paper mainly studies the geometrical evaluation criterion for validity of energy beams emitted by inclined cylindrical flames and received by other surfaces. Compared to Mudan's formula results for a straight cylinder or a cylinder with 30° tilt angle, the calculated view factors range from 0.0043 to 0.2742 and the predicted view factors agree well with Mudan's results. The changing trend and values of incident heat fluxes computed by the model is consistent with experimental data measured by Rangwala et al. As a case study, incident heat fluxes on a gasoline tank, both the side and the top surface are calculated by the model. The heat radiation is from an inclined cylindrical flame generated by another 1000 m3 gasoline tank 4.6 m away from it. The cone angle of the flame to the adjacent oil tank is 45° and the polar angle is 0°. The top surface and the side surface of the tank are divided into 960 and 5760 grids during the calculation, respectively. The maximum incident heat flux on the side surface is 39.64 and 51.31 kW/m2 on the top surface. Distributions of the incident heat flux on the surface of the oil tank and on the ground around the fire tank are obtained, too.

A Water Droplet Pinning and Heat Transfer Characteristics on an Inclined Hydrophobic Surface.

PubMed

Al-Sharafi, Abdullah; Yilbas, Bekir Sami; Ali, Haider; AlAqeeli, N

2018-02-15

A water droplet pinning on inclined hydrophobic surface is considered and the droplet heat transfer characteristics are examined. Solution crystallization of polycarbonate is carried out to create hydrophobic characteristics on the surface. The pinning state of the water droplet on the extreme inclined hydrophobic surface (0° ≤ δ ≤ 180°, δ being the inclination angle) is assessed. Heat transfer from inclined hydrophobic surface to droplet is simulated for various droplet volumes and inclination angles in line with the experimental conditions. The findings revealed that the hydrophobic surface give rise to large amount of air being trapped within texture, which generates Magdeburg like forces between the droplet meniscus and the textured surface while contributing to droplet pinning at extreme inclination angles. Two counter rotating cells are developed for inclination angle in the range of 0° < δ < 20° and 135° < δ < 180°; however, a single circulation cell is formed inside the droplet for inclination angle of 25° ≤ δ ≤ 135°. The Nusselt number remains high for the range of inclination angle of 45° ≤ δ ≤ 135°. Convection and conduction heat transfer enhances when a single and large circulation cell is formed inside the droplet.

Variable magnification glancing incidence x ray telescope

NASA Technical Reports Server (NTRS)

Hoover, Richard (Inventor)

1990-01-01

A multispectral glancing incidence x ray telescope is disclosed, which capable of broadband, high resolution imaging of solar and stellar x ray and extreme ultraviolet radiation sources includes a primary optical system which focuses the incoming radiation to a primary focus. Two or more ellipsoidal mirrors are positioned behind the primary focus at an inclination to the optical axis, each mirror having a concave surface coated with a multilayer synthetic microstructure coating to reflect a desired wavelength. The ellipsoidal mirrors are segments of respective ellipsoids having a common first focus coincident with the primary focus. A detector such as an x ray sensitive photographic film is positioned at the second focus of each of the ellipsoids so that each of the ellipsoidal mirrors may reflect the image at the first focus to the detector. In one embodiment the mirrors are inclined at different angles and has its respective second focus at a different location, separate detectors being located at the respective second focus. The mirrors are arranged so that the magnification and field of view differ, and a solenoid activated arm may withdraw at least one mirror from the beam to select the mirror upon which the beam is to impinge so that selected magnifications and fields of view may be detected.

Development of coated conductors by inclined substrate deposition

NASA Astrophysics Data System (ADS)

Balachandran, U.; Ma, B.; Li, M.; Fisher, B. L.; Koritala, R. E.; Miller, D. J.; Dorris, S. E.

2003-10-01

Inclined substrate deposition (ISD) offers the potential for rapid production of high-quality biaxially textured buffer layers suitable for YBa 2Cu 3O 7- δ (YBCO)-coated conductors. We have grown biaxially textured magnesium oxide (MgO) films on Hastelloy C276 (HC) substrates by ISD at deposition rates of 20-100 Å/s. Scanning electron microscopy of the ISD MgO films showed columnar grain structures with a roof-tile-shaped surface. X-ray pole figure analysis revealed that the c-axis of the ISD MgO films is titled at an angle ≈32° from the substrate normal. A small full-width at half maximum of ≈9° was observed for the φ-scan of MgO films. YBCO films were grown on ISD MgO buffered HC substrates by pulsed laser deposition and were determined to be biaxially aligned with the c-axis parallel to the substrate normal. The orientation relationship between the ISD template and the top YBCO film was investigated by X-ray pole figure analysis and transmission electron microscopy. A transport critical current density of Jc=5.5×10 5 A/cm 2 at 77 K in self-field was measured on a YBCO film that was 0.46-μm thick, 4-mm wide, 10-mm long.

Temperature sensitive surfaces and methods of making same

DOEpatents

Liang, Liang [Richland, WA; Rieke, Peter C [Pasco, WA; Alford, Kentin L [Pasco, WA

2002-09-10

Poly-n-isopropylacrylamide surface coatings demonstrate the useful property of being able to switch charateristics depending upon temperature. More specifically, these coatings switch from being hydrophilic at low temperature to hydrophobic at high temperature. Research has been conducted for many years to better characterize and control the properties of temperature sensitive coatings. The present invention provides novel temperature sensitive coatings on articles and novel methods of making temperature sensitive coatings that are disposed on the surfaces of various articles. These novel coatings contain the reaction products of n-isopropylacrylamide and are characterized by their properties such as advancing contact angles. Numerous other characteristics such as coating thickness, surface roughness, and hydrophilic-to-hydrophobic transition temperatures are also described. The present invention includes articles having temperature-sensitve coatings with improved properties as well as improved methods for forming temperature sensitive coatings.

A reliable method to grow vertically-aligned silicon nanowires by a novel ramp-cooling process

NASA Astrophysics Data System (ADS)

Ho, Tzuen-Wei; Hong, Franklin Chau-Nan

2012-08-01

We have grown silicon nanowires (SiNWs) on Si (1 1 1) substrates by gold-catalyzed vapor-liquid-solid (VLS) process using tetrachlorosilane (SiCl4) in a hot-wall chemical vapor deposition reactor. Even under the optimized conditions including H2 annealing to reduce the surface native oxide, epitaxial SiNWs of 150-200 nm in diameter often grew along all four <1 1 1> family directions with one direction vertical and three others inclined to the surface. Therefore, the growth of high degree ordered SiNW arrays along [1 1 1] only was attempted on Au-coated Si (1 1 1) by a ramp-cooling process utilizing the liquid phase epitaxy (LPE) mechanism. The Au-coated Si substrate was first annealed in H2 at 650 °C to form Au-Si alloy nanoparticles, and then ramp-cooled at a controlled rate to precipitate epitaxial Si seeds on the substrate based on LPE mechanism. The substrate was further heated in SiCl4/H2 to 850 °C for the VLS growths of SiNWs on the Si seeds. Thus, almost 100% vertically-aligned SiNWs along [1 1 1] only could be reproducibly grown on Si (1 1 1), without using a template or patterning the metal catalyst. The high-density vertically-aligned SiNWs have good potentials for solar cells and nano-devices.

Effect of the External Lubrication Method for a Rotary Tablet Press on the Adhesion of the Film Coating Layer.

PubMed

Kondo, Hisami; Toyota, Hiroyasu; Kamiya, Takayuki; Yamashita, Kazunari; Hakomori, Tadashi; Imoto, Junko; Kimura, Shin-Ichiro; Iwao, Yasunori; Itai, Shigeru

2017-01-01

External lubrication is a useful method which reduces the adhesion of powder to punches and dies by spraying lubricants during the tableting process. However, no information is available on whether the tablets prepared using an external lubrication system can be applicable for a film coating process. In this study, we evaluated the adhesion force of the film coating layer to the surface of tablets prepared using an external lubrication method, compared with those prepared using internal lubrication method. We also evaluated wettability, roughness and lubricant distribution state on the tablet surface before film coating, and investigated the relationship between peeling of the film coating layer and these tablet surface properties. Increasing lubrication through the external lubrication method decreased wettability of the tablet surface. However, no change was observed in the adhesion force of the film coating layer. On the other hand, increasing lubrication through the internal lubrication method, decreased both wettability of the tablet surface and the adhesion force of the film coating layer. The magnesium stearate distribution state on the tablet surface was assessed using an X-ray fluorescent analyzer and lubricant agglomerates were observed in the case of the internal lubrication method. However, the lubricant was uniformly dispersed in the external lubrication samples. These results indicate that the distribution state of the lubricant affects the adhesion force of the film coating layer, and external lubrication maintained sufficient lubricity and adhesion force of the film coating layer with a small amount of lubricant.

Fabrication of robust hydrogel coatings on polydimethylsiloxane substrates using micropillar anchor structures with chemical surface modification.

PubMed

Zhang, Hongbin; Bian, Chao; Jackson, John K; Khademolhosseini, Farzad; Burt, Helen M; Chiao, Mu

2014-06-25

A durable hydrophilic and protein-resistant surface of polydimethylsiloxane (PDMS) based devices is desirable in many biomedical applications such as implantable and microfluidic devices. This paper describes a stable antifouling hydrogel coating on PDMS surfaces. The coating method combines chemical modification and surface microstructure fabrication of PDMS substrates. Three-(trimethoxysilyl)propyl methacrylates containing C═C groups were used to modify PDMS surfaces with micropillar array structures fabricated by a replica molding method. The micropillar structures increase the surface area of PDMS surfaces, which facilitates secure bonding with a hydrogel coating compared to flat PMDS surfaces. The adhesion properties of the hydrogel coating on PDMS substrates were characterized using bending, stretching and water immersion tests. Long-term hydrophilic stability (maintaining a contact angle of 55° for a month) and a low protein adsorption property (35 ng/cm(2) of adsorbed BSA-FITC) of the hydrogel coated PDMS were demonstrated. This coating method is suitable for PDMS modification with most crosslinkable polymers containing C═C groups, which can be useful for improving the anti-biofouling performance of PDMS-based biomedical microdevices.

Motion and shape of partially non-wetting drops on inclined surfaces

NASA Astrophysics Data System (ADS)

Puthenveettil, Baburaj A.; Senthilkumar K, Vijaya; Hopfinger, E. J.; IIT Madras-LEGI Collaboration

2011-11-01

We study high Reynolds number (Re) motion of partially non- wetting liquid drops on inclined surfaces using (i) water on Fluoro-Alkyl Silane (FAS) coated glass and (ii) mercury on glass. The high hysteresis (35°) water drop experiments have been conducted for a range of inclination angles 26° < α <62° which give a range of Capillary numbers 0 . 0003 < Ca < 0 . 0075 and 137 < Re < 3142 . For low hysteresis (6°) mercury on glass experiments, 5 .5° < α < 14 .3° so that 0 . 0002 < Ca < 0 . 0023 and 3037 < Re < 20069 . It is shown that when Re >>103 for water and Re >> 19 for mercury, the observed velocities are accounted for by a boundary layer flow model. The dimensionless velocity in the inertial regime, Ca√{ Re } scales as the modified Bond number (Bom), while Ca Bom at low Re . We show that even at high Re , the dynamic contact angles (θd) depend only on Ca , similar to that in low Re drops. Only the model by Shikhmurzaev is consistent with the variation of dynamic contact angles in both mercury and water drops. We show that the corner transition at the rear of the mercury drop occurs at a finite, receding contact angle, which is predicted by a wedge flow model that we propose. For water drops, there is a direct transition to a rivulet from the oval shape at a critical ratio of receding to static contact angles.

Impact of air and water vapor environments on the hydrophobicity of surfaces.

PubMed

Weisensee, Patricia B; Neelakantan, Nitin K; Suslick, Kenneth S; Jacobi, Anthony M; King, William P

2015-09-01

Droplet wettability and mobility play an important role in dropwise condensation heat transfer. Heat exchangers and heat pipes operate at liquid-vapor saturation. We hypothesize that the wetting behavior of liquid water on microstructures surrounded by pure water vapor differs from that for water droplets in air. The static and dynamic contact angles and contact angle hysteresis of water droplets were measured in air and pure water vapor environments inside a pressure vessel. Pressures ranged from 60 to 1000 mbar, with corresponding saturation temperatures between 36 and 100°C. The wetting behavior was studied on four hydrophobic surfaces: flat Teflon-coated, micropillars, micro-scale meshes, and nanoparticle-coated with hierarchical micro- and nanoscale roughness. Static advancing contact angles are 9° lower in the water vapor environment than in air on a flat surface. One explanation for this reduction in contact angles is water vapor adsorption to the Teflon. On microstructured surfaces, the vapor environment has little effect on the static contact angles. In all cases, variations in pressure and temperature do not influence the wettability and mobility of the water droplets. In most cases, advancing contact angles increase and contact angle hysteresis decreases when the droplets are sliding or rolling down an inclined surface. Copyright © 2015 Elsevier Inc. All rights reserved.

Apparatus and method for measuring the thickness of a coating

DOEpatents

Carlson, Nancy M.; Johnson, John A.; Tow, David M.; Walter, John B

2002-01-01

An apparatus and method for measuring the thickness of a coating adhered to a substrate. An electromagnetic acoustic transducer is used to induce surface waves into the coating. The surface waves have a selected frequency and a fixed wavelength. Interpolation is used to determine the frequency of surface waves that propagate through the coating with the least attenuation. The phase velocity of the surface waves having this frequency is then calculated. The phase velocity is compared to known phase velocity/thickness tables to determine the thickness of the coating.

Coating Methods for Surface Modification of Ammonium Nitrate: A Mini-Review

PubMed Central

Elzaki, Baha I.; Zhang, Yue Jun

2016-01-01

Using ammonium nitrate (AN) as a propellant oxidizer is limited due to its hygroscopicity. This review consolidated the available information of various issues pertaining to the coating methods of the surface modification of ammonium nitrate for reducing its hygroscopicity. Moreover this review summarizes the recent advances and issues involved in ammonium nitrate surface modification by physical, chemical and encapsulation coating methods to reduce the hygroscopicity. Furthermore, coating materials, process conditions, and the hygroscopicity test conditions are extensively discussed along, with summaries of the advantages and disadvantages of each coating method. Our findings indicated that the investigation and development of anti-hygroscopicity of AN, and the mechanisms of surface modification by coating urgently require further research in order to further reduce the hygroscopicity. Therefore, this review is useful to researchers concerned with the improvement of ammonium salts’ anti-hygroscopicity. PMID:28773625

Assessment of postural stability using inertial measurement unit on inclined surfaces in healthy adults - biomed 2013.

PubMed

Frames, Chris; Soangra, Rahul; Lockhart, Thurmon E

2013-01-01

Fatal and nonfatal falls in the construction domain remain a significant issue in today’s workforce. The roofing industry in particular, annually ranks amongst the highest in all industries. Exposure to an inclined surface, such as an inclined roof surface, has been reported to have adverse effects on postural stability. The purpose of this preliminary study was to investigate the intra-individual differences in stability parameters on both inclined and level surfaces. Postural Stability (PS) and Limit of Stability (LOS) were assessed in seven healthy subjects (aged 25-35 years) on inclined and level surfaces using embedded force plates and an Inertial Measurement Unit (IMU). Four 90-second trials were collected on the inclined surface in distinctive positions: (1) Toes raised 20o above heel; (2) Heels raised 20o above toes (3); Transverse direction with dominant foot inverted at a lower height; (4) Transverse direction with non-dominant foot inverted at a lower height. Limit of Stability was evaluated by the two measurement devices in all four directions and margin of safety was quantified for each individual on both surfaces. The results reveal significant differences in postural stability between the flat surface condition and the inclined surface condition when subject was positioned perpendicular to the surface slope with one foot descended below the other; specifically, a significant increase was identified when visual support was interrupted. The findings lend support to the literature and will assist in future research regarding early detection of postural imbalance and preventative measures to reduce fall risks in professions where workers are consistently exposed to inclined surfaces.

Assessment of Postural Stability using Inertial Measurement Unit on Inclined Surfaces in Healthy Adults

PubMed Central

Frames, Chris; Soangra, Rahul; Lockhart, Thurmon E.

2013-01-01

Fatal and nonfatal falls in the construction domain remain a significant issue in today’s workforce. The roofing industry in particular, annually ranks amongst the highest in all industries. Exposure to an inclined surface, such as an inclined roof surface, has been reported to have adverse effects on postural stability. The purpose of this preliminary study was to investigate the intra-individual differences in stability parameters on both inclined and level surfaces. Postural Stability (PS) and Limit of Stability (LOS) were assessed in seven healthy subjects (aged 25-35 years) on inclined and level surfaces using embedded force plates and an Inertial Measurement Unit (IMU). Four 90-second trials were collected on the inclined surface in distinctive positions: (1) Toes raised 20° above heel; (2) Heels raised 20° above toes (3); Transverse direction with dominant foot inverted at a lower height; (4) Transverse direction with non-dominant foot inverted at a lower height. Limit of Stability was evaluated by the two measurement devices in all four directions and margin of safety was quantified for each individual on both surfaces. The results reveal significant differences in postural stability between the flat surface condition and the inclined surface condition when subject was positioned perpendicular to the surface slope with one foot descended below the other; specifically, a significant increase was identified when visual support was interrupted. The findings lend support to the literature and will assist in future research regarding early detection of postural imbalance and preventative measures to reduce fall risks in professions where workers are consistently exposed to inclined surfaces. PMID:23686205

Surface characteristics of a novel hydroxyapatite-coated dental implant

PubMed Central

Jung, Ui-Won; Hwang, Ji-Wan; Choi, Da-Yae; Hu, Kyung-Seok; Kwon, Mi-Kyung; Choi, Seong-Ho

2012-01-01

Purpose This study evaluated the surface characteristics and bond strength produced using a novel technique for coating hydroxyapatite (HA) onto titanium implants. Methods HA was coated on the titanium implant surface using a super-high-speed (SHS) blasting method with highly purified HA. The coating was performed at a low temperature, unlike conventional HA coating methods. Coating thickness was measured. The novel HA-coated disc was fabricated. X-ray diffraction analysis was performed directly on the disc to evaluate crystallinity. Four novel HA-coated discs and four resorbable blast medium (RBM) discs were prepared. Their surface roughnesses and areas were measured. Five puretitanium, RBM-treated, and novel HA-coated discs were prepared. Contact angle was measured. Two-way analysis of variance and the post-hoc Scheffe's test were used to analyze differences between the groups, with those with a probability of P<0.05 considered to be statistically significant. To evaluate exfoliation of the coating layer, 7 sites on the mandibles from 7 mongrel dogs were used. Other sites were used for another research project. In total, seven novel HA-coated implants were placed 2 months after extraction of premolars according to the manufacturer's instructions. The dogs were sacrificed 8 weeks after implant surgery. Implants were removed using a ratchet driver. The surface of the retrieved implants was evaluated microscopically. Results A uniform HA coating layer was formed on the titanium implants with no deformation of the RBM titanium surface microtexture when an SHS blasting method was used. Conclusions These HA-coated implants exhibited increased roughness, crystallinity, and wettability when compared with RBM implants. PMID:22586524

Method of measuring metal coating adhesion

DOEpatents

Roper, J.R.

A method for measuring metal coating adhesion to a substrate material comprising the steps of preparing a test coupon of substrate material having the metal coating applied to one surface thereof, applying a second metal coating of gold or silver to opposite surfaces of the test coupon by hot hollow cathode process, applying a coating to one end of each of two pulling rod members, joining the coated ends of the pulling rod members to said opposite coated surfaces of the test coupon by a solid state bonding technique and finally applying instrumented static tensile loading to the pulling rod members until fracture of the metal coating adhesion to the substrate material occurs.

Method of measuring metal coating adhesion

DOEpatents

Roper, John R.

1985-01-01

A method for measuring metal coating adhesion to a substrate material comprising the steps of preparing a test coupon of substrate material having the metal coating applied to one surface thereof, applying a second metal coating of gold or silver to opposite surfaces of the test coupon by hot hollow cathode process, applying a coating to one end of each of two pulling rod members, joining the coated ends of the pulling rod members to said opposite coated surfaces of the test coupon by a solid state bonding technique and finally applying instrumented static tensile loading to the pulling rod members until fracture of the metal coating adhesion to the substrate material occurs.

Optimization of the acoustic absorption coefficients of certain functional absorbents

NASA Technical Reports Server (NTRS)

Pocsa, V.; Biborosch, L.; Veres, A.; Halpert, E.; Lorian, R.; Botos, T.

1974-01-01

The sound absorption coefficients of some functional absorbents (mineral wool plates) are determined by the reverberation chamber method. The influence of the angle of inclination of the sound absorbing material with respect to the surface to be treated is analyzed as well as the influence of the covering index, defined as the ratio of the designed area of a plate and the area of the treated surface belonging to another plate. As compared with the conventional method of applying sound-absorbing plates, the analyzed structures have a higher technological and economical efficiency. The optimum structure corresponds to an angle of inclination of 15 deg and a covering index of 0.8.

A Rapid Method to Achieve Aero-Engine Blade Form Detection

PubMed Central

Sun, Bin; Li, Bing

2015-01-01

This paper proposes a rapid method to detect aero-engine blade form, according to the characteristics of an aero-engine blade surface. This method first deduces an inclination error model in free-form surface measurements based on the non-contact laser triangulation principle. Then a four-coordinate measuring system was independently developed, a special fixture was designed according to the blade shape features, and a fast measurement of the blade features path was planned. Finally, by using the inclination error model for correction of acquired data, the measurement error that was caused by tilt form is compensated. As a result the measurement accuracy of the Laser Displacement Sensor was less than 10 μm. After the experimental verification, this method makes full use of optical non-contact measurement fast speed, high precision and wide measuring range of features. Using a standard gauge block as a measurement reference, the coordinate system conversion data is simple and practical. It not only improves the measurement accuracy of the blade surface, but also its measurement efficiency. Therefore, this method increases the value of the measurement of complex surfaces. PMID:26039420

A rapid method to achieve aero-engine blade form detection.

PubMed

Sun, Bin; Li, Bing

2015-06-01

This paper proposes a rapid method to detect aero-engine blade form, according to the characteristics of an aero-engine blade surface. This method first deduces an inclination error model in free-form surface measurements based on the non-contact laser triangulation principle. Then a four-coordinate measuring system was independently developed, a special fixture was designed according to the blade shape features, and a fast measurement of the blade features path was planned. Finally, by using the inclination error model for correction of acquired data, the measurement error that was caused by tilt form is compensated. As a result the measurement accuracy of the Laser Displacement Sensor was less than 10 μm. After the experimental verification, this method makes full use of optical non-contact measurement fast speed, high precision and wide measuring range of features. Using a standard gauge block as a measurement reference, the coordinate system conversion data is simple and practical. It not only improves the measurement accuracy of the blade surface, but also its measurement efficiency. Therefore, this method increases the value of the measurement of complex surfaces.

Method and apparatus for reading lased bar codes on shiny-finished fuel rod cladding tubes

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

Goldenfield, M.P.; Lambert, D.V.

1990-10-02

This patent describes, in a nuclear fuel rod identification system, a method of reading a bar code etched directly on a surface of a nuclear fuel rod. It comprises: defining a pair of light diffuser surfaces adjacent one another but in oppositely inclined relation to a beam of light emitted from a light reader; positioning a fuel rod, having a cylindrical surface portion with a bar code etched directly thereon, relative to the light diffuser surfaces such that the surfaces are disposed adjacent to and in oppositely inclined relation along opposite sides of the fuel rod surface portion and themore » fuel rod surface portion is aligned with the beam of light emitted from the light reader; directing the beam of light on the bar code on fuel rod cylindrical surface portion such that the light is reflected therefrom onto one of the light diffuser surfaces; and receiving and reading the reflected light from the bar code via the one of the light diffuser surfaces to the light reader.« less

Precise on-machine extraction of the surface normal vector using an eddy current sensor array

NASA Astrophysics Data System (ADS)

Wang, Yongqing; Lian, Meng; Liu, Haibo; Ying, Yangwei; Sheng, Xianjun

2016-11-01

To satisfy the requirements of on-machine measurement of the surface normal during complex surface manufacturing, a highly robust normal vector extraction method using an Eddy current (EC) displacement sensor array is developed, the output of which is almost unaffected by surface brightness, machining coolant and environmental noise. A precise normal vector extraction model based on a triangular-distributed EC sensor array is first established. Calibration of the effects of object surface inclination and coupling interference on measurement results, and the relative position of EC sensors, is involved. A novel apparatus employing three EC sensors and a force transducer was designed, which can be easily integrated into the computer numerical control (CNC) machine tool spindle and/or robot terminal execution. Finally, to test the validity and practicability of the proposed method, typical experiments were conducted with specified testing pieces using the developed approach and system, such as an inclined plane and cylindrical and spherical surfaces.

Method for nondestructive testing of the film coating behavior of surface acoustic wave (SAW) sensors

NASA Astrophysics Data System (ADS)

Taslakov, M. A.; Avramov, I. D.

2010-04-01

This paper presents a practical non-destructive method for studying the film coating behavior of SAW devices by using a water soluble dielectric film (manitol) deposited on the SAW device surface by resistive evaporation. After measuring the electrical parameters of the film coated SAW device, the film can easily be removed from its surface by water rinsing without causing any damage to it. The SAW device can then be used over and over again in a large number of film depositions. The method was tested on a 1 GHz surface transverse wave (STW) resonator coated with manitol of varying thickness. After each coating and evaluation, the STW device was successfully recovered without significant performance degradation. Data is presented on the electrical changes of the STW device as a result of depositing manitol coatings of various thicknesses.

Methods for making deposited films with improved microstructures

DOEpatents

Patten, James W.; Moss, Ronald W.; McClanahan, Edwin D.

1982-01-01

Methods for improving microstructures of line-of-sight deposited films are described. Columnar growth defects ordinarily produced by geometrical shadowing during deposition of such films are eliminated without resorting to post-deposition thermal or mechanical treatments. The native, as-deposited coating qualities, including homogeneity, fine grain size, and high coating-to-substrate adherence, can thus be retained. The preferred method includes the steps of emitting material from a source toward a substrate to deposit a coating non-uniformly on the substrate surface, removing a portion of the coating uniformly over the surface, again depositing material onto the surface, but from a different direction, and repeating the foregoing steps. The quality of line-of-sight deposited films such as those produced by sputtering, progressively deteriorates as the angle of incidence between the flux and the surface becomes increasingly acute. Depositing non-uniformly, so that the coating becomes progressively thinner as quality deteriorates, followed by uniformly removing some of the coating, such as by resputtering, eliminates the poor quality portions, leaving only high quality portions of the coating. Subsequently sputtering from a different direction applies a high quality coating to other regions of the surface. Such steps can be performed either simultaneously or sequentially to apply coatings of a uniformly high quality, closed microstructure to three-dimensional or larger planar surfaces.

METHOD OF COATING SURFACES WITH BORON

DOEpatents

Martin, G.R.

1949-10-11

A method of forming a thin coating of boron on metallic, glass, or other surfaces is described. The method comprises heating the article to be coated to a temperature of about 550 d C in an evacuated chamber and passing trimethyl boron, triethyl boron, or tripropyl boron in the vapor phase and under reduced pressure into contact with the heated surface causing boron to be deposited in a thin film.

A Novel Method for Depositing Precious Metal Films on Difficult Surfaces

NASA Technical Reports Server (NTRS)

Veitch, L. C.; Phillip, W. H.

1994-01-01

A guanidine-based vehicle was developed to deposit precious metal coatings on surfaces known to be difficult to coat. To demonstrate this method, a platinum coating was deposited on alumina fibers using a guanidine-platinum solution. X-ray diffraction confirmed that the only species present in the coating was platinum and that all of the carbon species had been removed upon heat treatment. SEM results showed that some porosity was present but that the coatings uniformly covered the fiber surface and adhered well to the finer.

The Effect of Surface Tension on the Gravity-driven Thin Film Flow of Newtonian and Power-law Fluids.

PubMed

Hu, Bin; Kieweg, Sarah L

2012-07-15

Gravity-driven thin film flow is of importance in many fields, as well as for the design of polymeric drug delivery vehicles, such as anti-HIV topical microbicides. There have been many prior works on gravity-driven thin films. However, the incorporation of surface tension effect has not been well studied for non-Newtonian fluids. After surface tension effect was incorporated into our 2D (i.e. 1D spreading) power-law model, we found that surface tension effect not only impacted the spreading speed of the microbicide gel, but also had an influence on the shape of the 2D spreading profile. We observed a capillary ridge at the front of the fluid bolus. Previous literature shows that the emergence of a capillary ridge is strongly related to the contact line fingering instability. Fingering instabilities during epithelial coating may change the microbicide gel distribution and therefore impact how well it can protect the epithelium. In this study, we focused on the capillary ridge in 2D flow and performed a series of simulations and showed how the capillary ridge height varies with other parameters, such as surface tension coefficient, inclination angle, initial thickness, and power-law parameters. As shown in our results, we found that capillary ridge height increased with higher surface tension, steeper inclination angle, bigger initial thickness, and more Newtonian fluids. This study provides the initial insights of how to optimize the flow and prevent the appearance of a capillary ridge and fingering instability.

Kinetic potential influences visual and remote haptic perception of affordances for standing on an inclined surface.

PubMed

Malek, Eric A; Wagman, Jeffrey B

2008-01-01

The ability of a perceiver-actor to perform a particular behaviour depends on their ability to generate and control the muscular forces required to perform that behaviour. If an intended behaviour is to be successful, perception must be relative to this ability. We investigated whether perceiver-actors were sensitive to how changes in their mass distribution influenced their ability to stand on an inclined surface. Participants reported whether they would be able to stand on an inclined surface while wearing a weighted backpack on their back, while wearing a weighted backpack on their front, and while not wearing a weighted backpack. In addition, participants performed this task by either viewing the surface or exploring it with a hand-held rod (while blindfolded). The results showed that perception of affordances for standing on the inclined surface depended on how the backpack influenced the ability of the participant to stand on the surface. Specifically, perceptual boundaries occurred at steeper inclinations when participants wore the backpack on their front than when they wore it on their back. Moreover, this pattern occurred regardless of the perceptual modality by which the participants explored the inclined surface.

High Thermal Conductivity of Copper Matrix Composite Coatings with Highly-Aligned Graphite Nanoplatelets

PubMed Central

Tagliaferri, Vincenzo; Ucciardello, Nadia

2017-01-01

Nanocomposite coatings with highly-aligned graphite nanoplatelets in a copper matrix were successfully fabricated by electrodeposition. For the first time, the disposition and thermal conductivity of the nanofiller has been evaluated. The degree of alignment and inclination of the filling materials has been quantitatively evaluated by polarized micro-Raman spectroscopy. The room temperature values of the thermal conductivity were extracted for the graphite nanoplatelets by the dependence of the Raman G-peak frequency on the laser power excitation. Temperature dependency of the G-peak shift has been also measured. Most remarkable is the global thermal conductivity of 640 ± 20 W·m−1·K−1 (+57% of copper) obtained for the composite coating by the flash method. Our experimental results are accounted for by an effective medium approximation (EMA) model that considers the influence of filler geometry, orientation, and thermal conductivity inside a copper matrix. PMID:29068424

Thin film application device and method for coating small aperture vacuum vessels

DOEpatents

Walters, Dean R; Este, Grantley O

2015-01-27

A device and method for coating an inside surface of a vessel is provided. In one embodiment, a coating device comprises a power supply and a diode in electrical communication with the power supply, wherein electrodes comprising the diode reside completely within the vessel. The method comprises reversibly sealing electrodes in a vessel, sputtering elemental metal or metal compound on the surface while maintaining the surface in a controlled atmosphere.

Method of producing adherent metal oxide coatings on metallic surfaces

DOEpatents

Lane, Michael H.; Varrin, Jr., Robert D.

2001-01-01

Provided is a process of producing an adherent synthetic corrosion product (sludge) coating on metallic surfaces. The method involves a chemical reaction between a dry solid powder mixture of at least one reactive metal oxide with orthophosphoric acid to produce a coating in which the particles are bound together and the matrix is adherent to the metallic surface.

A Novel Method of Coating Orthodontic Archwires with Nanoparticles

PubMed Central

Syed, Shibli S; Kulkarni, Dinraj; Todkar, Rohit; Bagul, Ravikiran S; Parekh, Kreena; Bhujbal, Nikita

2015-01-01

Background: The major hazard to the orthodontic tooth movement is the friction developing at the bracket wire interface. In the past, there have been various attempts to reduce this friction. We believe that coating the commercially available orthodontic wires with nanoparticles can result in a successful reduction of this friction. The objective of this study is to develop a novel method of coating orthodontic archwires with nanoparticles. Materials and Methods: Stainless steel (Ormco, CA, USA), titanium molybdenum alloy (Ormco, CA, USA) and nickel-titanium (G and H Wire Company, USA) orthodontic wires with a rectangular cross-section dimension of 0.019”× 0.025”, were selected. The wires were later coated with a uniform and smooth nanoparticle film using 100 ml nanocremics. The coating procedure described in this article is a sol-gel thin film dip coating method. Results: The coating procedure was verified by comparing the surface topography of nanocoated archwires with the commercially available archwires in an environmental scanning electron microscope (ESEM). The ESEM images prove that the surface topography of the coated wires was found to be smoother with less surface deteriorations as compared to the commercially available wires. Conclusion: Commercially available orthodontic wires can be successfully coated using a novel method of sol-gel thin film dip coating method. PMID:26028899

The biological response to laser-aided direct metal-coated Titanium alloy (Ti6Al4V)

PubMed Central

Shin, T.; Lim, D.; Kim, Y. S.; Kim, S. C.; Jo, W. L.

2018-01-01

Objectives Laser-engineered net shaping (LENS) of coated surfaces can overcome the limitations of conventional coating technologies. We compared the in vitro biological response with a titanium plasma spray (TPS)-coated titanium alloy (Ti6Al4V) surface with that of a Ti6Al4V surface coated with titanium using direct metal fabrication (DMF) with 3D printing technologies. Methods The in vitro ability of human osteoblasts to adhere to TPS-coated Ti6Al4V was compared with DMF-coating. Scanning electron microscopy (SEM) was used to assess the structure and morphology of the surfaces. Biological and morphological responses to human osteoblast cell lines were then examined by measuring cell proliferation, alkaline phosphatase activity, actin filaments, and RUNX2 gene expression. Results Morphological assessment of the cells after six hours of incubation using SEM showed that the TPS- and DMF-coated surfaces were largely covered with lamellipodia from the osteoblasts. Cell adhesion appeared similar in both groups. The differences in the rates of cell proliferation and alkaline phosphatase activities were not statistically significant. Conclusions The DMF coating applied using metal 3D printing is similar to the TPS coating, which is the most common coating process used for bone ingrowth. The DMF method provided an acceptable surface structure and a viable biological surface. Moreover, this method is automatable and less complex than plasma spraying. Cite this article: T. Shin, D. Lim, Y. S. Kim, S. C. Kim, W. L. Jo, Y. W. Lim. The biological response to laser-aided direct metal-coated Titanium alloy (Ti6Al4V). Bone Joint Res 2018;7:357–361. DOI: 10.1302/2046-3758.75.BJR-2017-0222.R1. PMID:29922456

Measurement of Interfacial Profiles of Wavy Film Flow on Inclined Wall

NASA Astrophysics Data System (ADS)

Rosli, N.; Amagai, K.

2016-02-01

Falling liquid films on inclined wall present in many industrial processes such as in food processing, seawater desalination and electronic devices manufacturing industries. In order to ensure an optimal efficiency of the operation in these industries, a fundamental study on the interfacial flow profiles of the liquid film is of great importance. However, it is generally difficult to experimentally predict the interfacial profiles of liquid film flow on inclined wall due to the instable wavy flow that usually formed on the liquid film surface. In this paper, the liquid film surface velocity was measured by using a non-intrusive technique called as photochromic dye marking method. This technique utilizes the color change of liquid containing the photochromic dye when exposed to the UV light source. The movement of liquid film surface marked by the UV light was analyzed together with the wave passing over the liquid. As a result, the liquid film surface was found to slightly shrink its gradual movement when approached by the wave before gradually move again after the intersection with the wave.

Surface Characteristics of Silicon Nanowires/Nanowalls Subjected to Octadecyltrichlorosilane Deposition and n-octadecane Coating

PubMed Central

Yilbas, Bekir Sami; Salhi, Billel; Yousaf, Muhammad Rizwan; Al-Sulaiman, Fahad; Ali, Haider; Al-Aqeeli, Nasser

2016-01-01

In this study, nanowires/nanowalls were generated on a silicon wafer through a chemical etching method. Octadecyltrichlorosilane (OTS) was deposited onto the nanowire/nanowall surfaces to alter their hydrophobicity. The hydrophobic characteristics of the surfaces were further modified via a 1.5-μm-thick layer of n-octadecane coating on the OTS-deposited surface. The hydrophobic characteristics of the resulting surfaces were assessed using the sessile water droplet method. Scratch and ultraviolet (UV)-visible reflectivity tests were conducted to measure the friction coefficient and reflectivity of the surfaces. The nanowires formed were normal to the surface and uniformly extended 10.5 μm to the wafer surface. The OTS coating enhanced the hydrophobic state of the surface, and the water contact angle increased from 27° to 165°. The n-octadecane coating formed on the OTS-deposited nanowires/nanowalls altered the hydrophobic state of the surface. This study provides the first demonstration that the surface wetting characteristics change from hydrophobic to hydrophilic after melting of the n-octadecane coating. In addition, this change is reversible; i.e., the hydrophilic surface becomes hydrophobic after the n-octadecane coating solidifies at the surface, and the process again occurs in the opposite direction after the n-octadecane coating melts. PMID:27934970

Silver/hydroxyapatite composite coatings on porous titanium surfaces by sol-gel method.

PubMed

Qu, Jie; Lu, Xiong; Li, Dan; Ding, Yonghui; Leng, Yang; Weng, Jie; Qu, Shuxin; Feng, Bo; Watari, Fumio

2011-04-01

Hydroxyapatite (HA) coatings loaded with nanosilver particles is an attractive method to impart the HA coating with antibacterial properties. Producing Ag/HA coatings on porous Ti substrates have been an arduous job since commonly used line-of-sight techniques are not able to deposit uniform coatings on the inner pore surfaces of the porous Ti. In this study, porous Ti scaffolds with high porosity and interconnected structures were prepared by polymer impregnating method. A sol-gel process was used to produce uniform Ag/HA composite coatings on the surfaces of porous Ti substrates. Ca(NO(3) )(2) ·4H(2) O and P(2) O(5) in an ethyl alcohol based system was selected to prepare the sol, which ensured the homogeneous distribution of Ag in the sol. The characterization revealed that silver particles uniformly distributed in the coatings without agglomeration. High antibacterial ratio (>95%), against E. coli and S. albus was expressed by the silver-containing coatings (Ag/HA 0.8 and 1.6 wt %). The biocompatibility of the Ag/HA 0.8 surfaces was as good as that of pure HA surface, as revealed by culturing osteoblasts on them. The results indicated that Ag/HA 0.8 had the good balance between the biocompatibility and antibacterial properties of the coatings. Copyright © 2011 Wiley Periodicals, Inc.

Method for preparing hydride configurations and reactive metal surfaces

DOEpatents

Silver, Gary L.

1988-08-16

A method for preparing highly hydrogen-reactive surfaces on metals which normally require substantial heating, high pressures, or an extended induction period, which involves pretreatment of said surfaces with either a non-oxidizing acid or hydrogen gas to form a hydrogen-bearing coating on said surfaces, and subsequently heating said coated metal in the absence of moisture and oxygen for a period sufficient to decompose said coating and cooling said metal to room temperature. Surfaces so treated will react almost instantaneously with hydrogen gas at room temperature and low pressure. The method is particularly applicable to uranium, thorium, and lanthanide metals.

THE PHOTOMETRIC AND KINEMATIC STRUCTURE OF FACE-ON DISK GALAXIES. III. KINEMATIC INCLINATIONS FROM H{alpha} VELOCITY FIELDS

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

Andersen, David R.; Bershady, Matthew A., E-mail: david.andersen@nrc-cnrc.gc.ca, E-mail: mab@astro.wisc.edu

2013-05-01

Using the integral field unit DensePak on the WIYN 3.5 m telescope we have obtained H{alpha} velocity fields of 39 nearly face-on disks at echelle resolutions. High-quality, uniform kinematic data and a new modeling technique enabled us to derive accurate and precise kinematic inclinations with mean i{sub kin} = 23 Degree-Sign for 90% of these galaxies. Modeling the kinematic data as single, inclined disks in circular rotation improves upon the traditional tilted-ring method. We measure kinematic inclinations with a precision in sin i of 25% at 20 Degree-Sign and 6% at 30 Degree-Sign . Kinematic inclinations are consistent with photometricmore » and inverse Tully-Fisher inclinations when the sample is culled of galaxies with kinematic asymmetries, for which we give two specific prescriptions. Kinematic inclinations can therefore be used in statistical ''face-on'' Tully-Fisher studies. A weighted combination of multiple, independent inclination measurements yield the most precise and accurate inclination. Combining inverse Tully-Fisher inclinations with kinematic inclinations yields joint probability inclinations with a precision in sin i of 10% at 15 Degree-Sign and 5% at 30 Degree-Sign . This level of precision makes accurate mass decompositions of galaxies possible even at low inclination. We find scaling relations between rotation speed and disk-scale length identical to results from more inclined samples. We also observe the trend of more steeply rising rotation curves with increased rotation speed and light concentration. This trend appears to be uncorrelated with disk surface brightness.« less

Virtual reconstruction of glenoid bone defects using a statistical shape model.

PubMed

Plessers, Katrien; Vanden Berghe, Peter; Van Dijck, Christophe; Wirix-Speetjens, Roel; Debeer, Philippe; Jonkers, Ilse; Vander Sloten, Jos

2018-01-01

Description of the native shape of a glenoid helps surgeons to preoperatively plan the position of a shoulder implant. A statistical shape model (SSM) can be used to virtually reconstruct a glenoid bone defect and to predict the inclination, version, and center position of the native glenoid. An SSM-based reconstruction method has already been developed for acetabular bone reconstruction. The goal of this study was to evaluate the SSM-based method for the reconstruction of glenoid bone defects and the prediction of native anatomic parameters. First, an SSM was created on the basis of 66 healthy scapulae. Then, artificial bone defects were created in all scapulae and reconstructed using the SSM-based reconstruction method. For each bone defect, the reconstructed surface was compared with the original surface. Furthermore, the inclination, version, and glenoid center point of the reconstructed surface were compared with the original parameters of each scapula. For small glenoid bone defects, the healthy surface of the glenoid was reconstructed with a root mean square error of 1.2 ± 0.4 mm. Inclination, version, and glenoid center point were predicted with an accuracy of 2.4° ± 2.1°, 2.9° ± 2.2°, and 1.8 ± 0.8 mm, respectively. The SSM-based reconstruction method is able to accurately reconstruct the native glenoid surface and to predict the native anatomic parameters. Based on this outcome, statistical shape modeling can be considered a successful technique for use in the preoperative planning of shoulder arthroplasty. Copyright © 2017 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Elsevier Inc. All rights reserved.

Medical implants and methods of making medical implants

DOEpatents

Shaw, Wendy J; Yonker, Clement R; Fulton, John L; Tarasevich, Barbara J; McClain, James B; Taylor, Doug

2014-09-16

A medical implant device having a substrate with an oxidized surface and a silane derivative coating covalently bonded to the oxidized surface. A bioactive agent is covalently bonded to the silane derivative coating. An implantable stent device including a stent core having an oxidized surface with a layer of silane derivative covalently bonded thereto. A spacer layer comprising polyethylene glycol (PEG) is covalently bonded to the layer of silane derivative and a protein is covalently bonded to the PEG. A method of making a medical implant device including providing a substrate having a surface, oxidizing the surface and reacting with derivitized silane to form a silane coating covalently bonded to the surface. A bioactive agent is then covalently bonded to the silane coating. In particular instances, an additional coating of bio-absorbable polymer and/or pharmaceutical agent is deposited over the bioactive agent.

Entrapment of subtilisin in ceramic sol-gel coating for antifouling applications.

PubMed

Regina, Viduthalai Rasheedkhan; Søhoel, Helmer; Lokanathan, Arcot Raghupathi; Bischoff, Claus; Kingshott, Peter; Revsbech, Niels Peter; Meyer, Rikke Louise

2012-11-01

Enzymes with antifouling properties are of great interest in developing nontoxic antifouling coatings. A bottleneck in developing enzyme-based antifouling coatings is to immobilize the enzyme in a suitable coating matrix without compromising its activity and stability. Entrapment of enzymes in ceramics using the sol-gel method is known to have several advantages over other immobilization methods. The sol-gel method can be used to make robust coatings, and the aim of this study was to explore if sol-gel technology can be used to develop robust coatings harboring active enzymes for antifouling applications. We successfully entrapped a protease, subtilisin (Savinase, Novozymes), in a ceramic coating using a sol-gel method. The sol-gel formulation, when coated on a stainless steel surface, adhered strongly and cured at room temperature in less than 8 h. The resultant coating was smoother and less hydrophobic than stainless steel. Changes in the coating's surface structure, thickness and chemistry indicate that the coating undergoes gradual erosion in aqueous medium, which results in release of subtilisin. Subtilisin activity in the coating increased initially, and then gradually decreased. After 9 months, 13% of the initial enzyme activity remained. Compared to stainless steel, the sol-gel-coated surfaces with active subtilisin were able to reduce bacterial attachment of both Gram positive and Gram negative bacteria by 2 orders of magnitude. Together, our results demonstrate that the sol-gel method is a promising coating technology for entrapping active enzymes, presenting an interesting avenue for enzyme-based antifouling solutions.

Coating and curing apparatus and methods

DOEpatents

Brophy, Brenor L; Maghsoodi, Sina; Neyman, Patrick J; Gonsalves, Peter R; Hirsch, Jeffrey G; Yang, Yu S

2015-02-24

Disclosed are coating apparatus including flow coating and roll-coating that may be used for uniform sol-gel coating of substrates such as glass, solar panels, windows or part of an electronic display. Also disclosed are methods for substrate preparation, flow coating and roll coating. Lastly systems and methods for skin curing sol-gel coatings deposited onto the surface of glass substrates using a high temperature air-knife are disclosed.

Method for adhering a coating to a substrate structure

DOEpatents

Taxacher, Glenn Curtis; Crespo, Andres Garcia; Roberts, III, Herbert Chidsey

2015-02-17

A method for adhering a coating to a substrate structure comprises selecting a substrate structure having an outer surface oriented substantially parallel to a direction of radial stress, modifying the outer surface to provide a textured region having steps to adhere a coating thereto, and applying a coating to extend over at least a portion of the textured region, wherein the steps are oriented substantially perpendicular to the direction of radial stress to resist deformation of the coating relative to the substrate structure. A rotating component comprises a substrate structure having an outer surface oriented substantially parallel to a direction of radial stress. The outer surface defines a textured region having steps to adhere a coating thereto, and a coating extends over at least a portion of the textured region. The steps are oriented substantially perpendicular to the direction of radial stress to resist creep.

40 CFR 60.725 - Test methods and procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Industrial Surface Coating: Surface Coating of Plastic Parts for Business Machines § 60.725 Test methods and...

40 CFR 60.725 - Test methods and procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) STANDARDS OF PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Industrial Surface Coating: Surface Coating of Plastic Parts for Business Machines § 60.725 Test methods and...

Method for non-destructive evaluation of ceramic coatings

DOEpatents

Peterson, Kristen A.; Rosen, Elias P.; Jordan, Eric H.; Shahbazmohamadi, Sina; Vakhtin, Andrei B.

2016-11-08

A method for evaluating the condition of a ceramic coating deposited on a substrate comprising illuminating the ceramic coating with light, measuring the intensity of light returned from the ceramic coating as function of depth in the coating and transverse position on the coating, and analyzing the measured light intensities to obtain one or more of intensity of the light returned from the exposed coating surface relative to the intensity of light returned from the coating/substrate interface, intensity of the light returned from the coating/substrate interface relative to the intensity of light returned from the bulk of the ceramic coating, determination of roughness at the exposed surface of the ceramic coating, and determination of roughness of the interface between the ceramic coating and underlying bond coat or substrate.

Process for non-contact removal of organic coatings from the surface of paintings

NASA Technical Reports Server (NTRS)

Banks, Bruce A. (Inventor); Rutledge, Sharon K. (Inventor)

1995-01-01

The present invention discloses a method of removing organic protective coatings from a painting. In the present invention degraded protective coatings such as lacquers, acrylics, natural resins, carbons, soot, and polyurethane are safely removed from the surface of a painting without contact to the surface of the painting. This method can be used for restoration of paintings when they have been damaged, through age, fire, etc.

Investigation of dynamic characteristics of a rotor system with surface coatings

NASA Astrophysics Data System (ADS)

Yang, Yang; Cao, Dengqing; Wang, Deyou

2017-02-01

A Jeffcott rotor system with surface coatings capable of describing the mechanical vibration resulting from unbalance and rub-impact is formulated in this article. A contact force model proposed recently to describe the impact force between the disc and casing with coatings is employed to do the dynamic analysis for the rotor system with rubbing fault. Due to the variation of penetration, the contact force model is correspondingly modified. Meanwhile, the Coulomb friction model is applied to simulate the friction characteristics. Then, the case study of rub-impact with surface coatings is simulated by the Runge-Kutta method, in which a linear interpolation method is adopted to predict the rubbing instant. Moreover, the dynamic characteristics of the rotor system with surface coatings are analyzed in terms of bifurcation plot, waveform, whirl orbit, Poincaré map and spectrum plot. And the effects of the hardness of surface coatings on the response are investigated as well. Finally, compared with the classical models, the modified contact force model is shown to be more suitable to solve the rub-impact of aero-engine with surface coatings.

Atomic oxygen interaction at defect sights in protective coatings on polymers flown on LDEF

NASA Technical Reports Server (NTRS)

Banks, Bruce A.; Degroh, Kim K.; Auer, Bruce M.; Gebauer, Linda; Lamoreaux, Cynthia

1993-01-01

Although the Long Duration Exposure Facility (LDEF) has exposed materials with a fixed orientation relative to the ambient low-Earth-orbital environment, arrival of atomic oxygen is angularly distributed as a result of the atomic oxygen's high temperature Maxwellian velocity distribution and the LDEF's orbital inclination. Thus, atomic oxygen entering defects in protective coatings on polymeric surfaces can cause wider undercut cavities than the size of the defect in the protective coating. Because only a small fraction of atomic oxygen reacts upon first impact with most polymeric materials, secondary reactions with lower energy thermally accommodated atomic oxygen can occur. The secondary reactions of scattered and/or thermally accommodated atomic oxygen also contribute to widening the undercut cavity beneath the protective coating defect. As the undercut cavity enlarges, exposing more polymer, the probability of atomic oxygen reacting with underlying polymeric material increases because of multiple opportunities for reaction. Thus, the effective atomic oxygen erosion yield for atoms entering defects increases above that of the unprotected material. Based on the results of analytical modeling and computational modeling, aluminized Kapton multilayer insulation exposed to atomic oxygen on row 9 lost the entire externally exposed layer of polyimide Kapton, yet based on the results of this investigation, the bottom surface aluminum film must have remained in place, but crazed. Atomic oxygen undercutting at defect sites in protective coatings on graphite epoxy composites indicates that between 40 to 100 percent of the atomic oxygen thermally accommodates upon impact, and that the reaction probability of thermally accommodated atomic oxygen may range from 7.7 x 10(exp -6) to 2.1 x 10(exp -3), depending upon the degree of thermal accommodation upon each impact.

Coating and curing apparatus and methods

DOEpatents

Brophy, Brenor L.; Gonsalves, Peter R.; Maghsoodi, Sina; Colson, Thomas E.; Yang, Yu S.; Abrams, Ze'ev R.

2016-04-19

Disclosed is a coating apparatus including flow coating and roll-coating that may be used for uniform sol-gel coating of substrates such as glass, solar panels, windows or part of an electronic display. Also disclosed are methods for substrate preparation, flow coating and roll coating. Lastly, systems and methods for curing sol-gel coatings deposited onto the surface of glass substrates using high temperature air-knives, infrared emitters and direct heat applicators are disclosed.

Robust and thermal-healing superhydrophobic surfaces by spin-coating of polydimethylsiloxane.

PubMed

Long, Mengying; Peng, Shan; Deng, Wanshun; Yang, Xiaojun; Miao, Kai; Wen, Ni; Miao, Xinrui; Deng, Wenli

2017-12-15

Superhydrophobic surfaces easily lose their excellent water-repellency after damages, which limit their broad applications in practice. Thus, the fabrication of superhydrophobic surfaces with excellent durability and thermal healing should be taken into consideration. In this work, robust superhydrophobic surfaces with thermal healing were successfully fabricated by spin-coating method. To achieve superhydrophobicity, cost-less and fluoride-free polydimethylsiloxane (PDMS) was spin-coated on rough aluminum substrates. After being spin-coated for one cycle, the superhydrophobic PDMS coated hierarchical aluminum (PDMS-H-Al) surfaces showed excellent tolerance to various chemical and mechanical damages in lab, and outdoor damages for 90days. When the PDMS-H-Al surfaces underwent severe damages such as oil contamination (peanut oil with high boiling point) or sandpaper abrasion (500g of force for 60cm), their superhydrophobicity would lose. Interestingly, through a heating process, cyclic oligomers generating from the partially decomposed PDMS acted as low-surface-energy substance on the damaged rough surfaces, leading to the recovery of superhydrophobicity. The relationship between the spin-coating cycles and surface wettability was also investigated. This paper provides a facile, fluoride-free and efficient method to fabricate superhydrophobic surfaces with thermal healing. Copyright © 2017. Published by Elsevier Inc.

Carbon decorative coatings by dip-, spin-, and spray-assisted layer-by-layer assembly deposition.

PubMed

Hong, Jinkee; Kang, Sang Wook

2011-09-01

We performed a comparative surface analysis of all-carbon nano-objects (multiwall carbon nanotubes (MWNT) or graphene oxide (GO) sheets) based multilayer coatings prepared using three widely used nanofilm fabrication methods: dip-, spin-, and spray-assisted layer-by-layer (LbL) deposition. The resultant films showed a marked difference in their growth mechanisms and surface morphologies. Various carbon decorative coatings were synthesized with different surface roughness values, despite identical preparation conditions. In particular, smooth to highly rough all-carbon surfaces, as determined by atomic force microscopy (AFM) and scanning electron microscopy (SEM), were readily obtained by manipulating the LbL deposition methods. As was confirmed by the AFM and SEM analyses, this finding indicated the fundamental morphological evolution of one-dimensional nano-objects (MWNT) and two-dimensional nano-objects (GO) by control of the surface roughness through the deposition method. Therefore, an analysis of the three LbL-assembly methods presented herein may offer useful information about the industrial use of carbon decorative coatings and provide an insight into ways to control the structures of multilayer coatings by tuning the morphologies of carbon nano-objects.

Numerical analysis of partially molten splat during thermal spray process using the finite element method

NASA Astrophysics Data System (ADS)

Zirari, M.; Abdellah El-Hadj, A.; Bacha, N.

2010-03-01

A finite element method is used to simulate the deposition of the thermal spray coating process. A set of governing equations is solving by a volume of fluid method. For the solidification phenomenon, we use the specific heat method (SHM). We begin by comparing the present model with experimental and numerical model available in the literature. In this study, completely molten or semi-molten aluminum particle impacts a H13 tool steel substrate is considered. Next we investigate the effect of inclination of impact of a partially molten particle on flat substrate. It was found that the melting state of the particle has great effects on the morphologies of the splat.

Deposited films with improved microstructures

DOEpatents

Patten, James W.; Moss, Ronald W.; McClanahan, Edwin D.

1984-01-01

Methods for improving microstructures of line-of-sight deposited films are described. Columnar growth defects ordinarily produced by geometrical shadowing during deposition of such films are eliminated without resorting to post-deposition thermal or mechanical treatments. The native, as-deposited coating qualities, including homogeneity, fine grain size, and high coating-to-substrate adherence, can thus be retained. The preferred method includes the steps of emitting material from a source toward a substrate to deposit a coating non-uniformly on the substrate surface, removing a portion of the coating uniformly over the surface, again depositing material onto the surface, but from a different direction, and repeating the foregoing steps. The quality of line-of-sight deposited films such as those produced by sputtering, progressively deteriorates as the angle of incidence between the flux and the surface becomes increasingly acute. Depositing non-uniformly, so that the coating becomes progressively thinner as quality deteriorates, followed by uniformly removing some of the coating, such as by resputtering, eliminates the poor quality portions, leaving only high quality portions of the coating. Subsequently sputtering from a different direction applies a high quality coating to other regions of the surface. Such steps can be performed either simultaneously or sequentially to apply coatings of a uniformly high quality, closed microstructure to three-dimensional or large planar surfaces.

Electrically atomised formulations of timolol maleate for direct and on-demand ocular lens coatings.

PubMed

Mehta, Prina; Al-Kinani, Ali A; Haj-Ahmad, Rita; Arshad, Muhammad Sohail; Chang, Ming-Wei; Alany, Raid G; Ahmad, Zeeshan

2017-10-01

Advances in nanotechnology have enabled solutions for challenging drug delivery targets. While the eye presents numerous emerging opportunities for delivery, analysis and sensing; issues persist for conventional applications. This includes liquid phase formulation localisation on the ocular surface once administered as formulated eye-drops; with the vast majority of dosage (>90%) escaping from the administered site due to tear production and various drainage mechanisms. The work presented here demonstrates a single needle electrohydrodynamic (EHD) engineering process to nano-coat (as an on demand and controllable fiber depositing method) the surface of multiple contact lenses rendering formulations to be stationary on the lens and at the bio-interface. The coating process was operational based on ejected droplet charge and glaucoma drug timolol maleate (TM) was used to demonstrate surface coating optimisation, bio-surface permeation properties (flux, using a bovine model) and various kinetic models thereafter. Polymers PVP, PNIPAM and PVP:PNIPAM (50:50%w/w) were used to encapsulate the active. Nano-fibrous and particulate samples were characterised using SEM, FTIR, DSC and TGA to confirm structural and thermal stability of surface coated formulations. More than 52% of nano-structured coatings (for all formulations) were <200nm in diameter. In vitro studies show coatings to exhibit biphasic release profiles; an initial burst release followed by sustained release; with TM-loaded PNIPAM coating releasing most drug after 24h (89.8%). Kinetic modelling (Higuchi, Korsmeyer-Peppas) was indicative of quasi-Fickian diffusion whilst biological evaluation demonstrates adequate ocular tolerability. Results from permeation studies indicate coated lenses are ideal to reduce dosing regimen, which in turn will reduce systemic drug absorption. Florescent microscopy demonstrated probe and probe embedded coating behaviour from lens surface in vitro. The multiple lens surface coating method demonstrates sustained drug release yielding promising results; suggesting both novel device and method to enhance drug activity at the eyes surface which will reduce formulation drainage. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Seat surface inclination may affect postural stability during Boccia ball throwing in children with cerebral palsy.

PubMed

Tsai, Yung-Shen; Yu, Yi-Chen; Huang, Po-Chang; Cheng, Hsin-Yi Kathy

2014-12-01

The aim of the study was to examine how seat surface inclination affects Boccia ball throwing movement and postural stability among children with cerebral palsy (CP). Twelve children with bilateral spastic CP (3 with gross motor function classification system Level I, 5 with Level II, and 4 with Level III) participated in this study. All participants underwent pediatric reach tests and ball throwing performance analyses while seated on 15° anterior- or posterior-inclined, and horizontal surfaces. An electromagnetic motion analysis system was synchronized with a force plate to assess throwing motion and postural stability. The results of the pediatric reach test (p = 0.026), the amplitude of elbow movement (p = 0.036), peak vertical ground reaction force (PVGRF) (p < 0.001), and movement range of the center of pressure (COP) (p < 0.020) were significantly affected by seat inclination during throwing. Post hoc comparisons showed that anterior inclination allowed greater amplitude of elbow movement and PVGRF, and less COP movement range compared with the other inclines. Posterior inclination yielded less reaching distance and PVGRF, and greater COP movement range compared with the other inclines. The anterior-inclined seat yielded superior postural stability for throwing Boccia balls among children with bilateral spastic CP, whereas the posterior-inclined seat caused difficulty. Copyright © 2014 Elsevier Ltd. All rights reserved.

METHOD FOR SOLDERING NORMALLY NON-SOLDERABLE ARTICLES

DOEpatents

McGuire, J.C.

1959-11-24

Methods are presented for coating and joining materials which are considered difficult to solder by utilizing an abrasive wheel and applying a bar of a suitable coating material, such as Wood's metal, to the rotating wheel to fill the cavities of the abrasive wheel and load the wheel with the coating material. The surface of the base material is then rubbed against the loaded rotating wheel, thereby coating the surface with the soft coating metal. The coating is a cohesive bonded layer and holds the base metal as tenaciously as a solder holds to easily solderable metals.

Photocatalytic activity of titania coatings synthesised by a combined laser/sol–gel technique

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

Adraider, Y.; Pang, Y.X., E-mail: F6098038@tees.ac.uk; Nabhani, F.

2014-06-01

Highlights: • Sol–gel method was used to prepare titania coatings. • Titania thin films were coated on substrate surface by dip coating. • Fibre laser was employed to irradiate the titania coated surfaces. • Photocatalytic efficiency of titania coatings was significantly improved after laser processing. - Abstract: Titania coatings were prepared using sol–gel method and then applied on the substrate surface by dip coating. Fibre laser (λ = 1064 nm) in continuous wave mode was used to irradiate the titania coated surfaces at different specific energies. The ATR-FTIR, XRD, SEM, EDS and contact angle measurement were employed to analyse surfacemore » morphology, phase composition and crystalline structure of laser-irradiated titania coatings, whilst the photocatalytic activity was evaluated by measuring the decomposition of methylene blue (MB) after exposure to the visible light for various illumination times. Results showed that the laser-irradiated titania coatings demonstrate significant different composition and microstructure in comparison with the as-coated from the same sol–gel titania. Photocatalytic efficiency of titania coatings was significantly improved after laser processing. The photocatalytic activity of laser-irradiated titania coatings was higher than that of the as-coated titania. The titania coating processed at laser specific energy of 6.5 J/mm{sup 2} exhibited the highest photocatalytic activity among all titania samples.« less

Method of coating metal surfaces to form protective metal coating thereon

DOEpatents

Krikorian, Oscar H.; Curtis, Paul G.

1992-01-01

A process is disclosed for forming a protective metal coating on a metal surface using a flux consisting of an alkali metal fluoride, an alkaline earth metal fluoride, an alkali metal fluoaluminate, an alkali metal fluosilicate, and mixtures thereof. The flux, in particulate form, is mixed with particles of a metal coating material which may comprise aluminum, chromium, mixtures thereof, and alloys containing at least 50 wt. % aluminum and the particulate mixture is applied to the metal surface in a single step, followed by heating the coated metal surface to a temperature sufficient to cause the metal coating material to react with the metal surface to form a protective reaction product in the form of a metal coating bonded to the metal surface. The metal surface which reacts with the metal coating material to form the protective coating may comprise Fe, Co, Ni, Ti, V, Cr, Mn, Zr, Nb, Mo, Tc, Hf, Ta, W, Re and alloys thereof.

Method of coating metal surfaces to form protective metal coating thereon

DOEpatents

Krikorian, O.H.; Curtis, P.G.

1992-03-31

A process is disclosed for forming a protective metal coating on a metal surface using a flux consisting of an alkali metal fluoride, an alkaline earth metal fluoride, an alkali metal fluoaluminate, an alkali metal fluosilicate, and mixtures thereof. The flux, in particulate form, is mixed with particles of a metal coating material which may comprise aluminum, chromium, mixtures thereof, and alloys containing at least 50 wt. % aluminum and the particulate mixture is applied to the metal surface in a single step, followed by heating the coated metal surface to a temperature sufficient to cause the metal coating material to react with the metal surface to form a protective reaction product in the form of a metal coating bonded to the metal surface. The metal surface which reacts with the metal coating material to form the protective coating may comprise Fe, Co, Ni, Ti, V, Cr, Mn, Zr, Nb, Mo, Tc, Hf, Ta, W, Re and alloys thereof. 1 figure.

Coating formulation and method for refinishing the surface of surface-damaged graphite articles

DOEpatents

Ardary, Z.L.; Benton, S.T.

1987-07-08

The described development is directed to a coating formulation for filling surface irregularities in graphite articles such as molds, crucibles, and matched die sets used in high-temperature metallurgical operations. The coating formulation of the present invention is formed of carbon black flour, thermosetting resin and a solvent for the resin. In affixing the coating to the article, the solvent is evaporated, the resin cured to bond the coating to the surface of the article and then pyrolyzed to convert the resin to carbon. Upon completion of the pyrolysis step, the coating is shaped and polished to provide the article with a surface restoration that is essentially similar to the original or desired surface finish without the irregularity.

Coating formulation and method for refinishing the surface of surface-damaged graphite articles

DOEpatents

Ardary, Zane L.; Benton, Samuel T.

1988-01-01

The described development is directed to a coating formulation for filling surface irregularities in graphite articles such as molds, crucibles, and matched die sets used in high-temperature metallurgical operations. The coating formulation of the present invention is formed of carbon black flour, thermosetting resin and a solvent for the resin. In affixing the coating to the article, the solvent is evaporated, the resin cured to bond the coating to the surface of the article and then pyrolyzed to convert the resin to carbon. Upon completion of the pyrolysis step, the coating is shaped and polished to provide the article with a surface restoration that is essentially similar to the original or desired surface finish without the irregularity.

Coating formulation and method for refinishing the surface of surface-damaged graphite articles

DOEpatents

Ardary, Z.L.; Benton, S.T.

1988-11-22

The described development is directed to a coating formulation for filling surface irregularities in graphite articles such as molds, crucibles, and matched die sets used in high-temperature metallurgical operations. The coating formulation of the present invention is formed of carbon black flour, thermosetting resin and a solvent for the resin. In affixing the coating to the article, the solvent is evaporated, the resin cured to bond the coating to the surface of the article and then pyrolyzed to convert the resin to carbon. Upon completion of the pyrolysis step, the coating is shaped and polished to provide the article with a surface restoration that is essentially similar to the original or desired surface finish without the irregularity.

Linkage between canopy water storage and drop size distributions of leaf drips

NASA Astrophysics Data System (ADS)

Nanko, Kazuki; Watanabe, Ai; Hotta, Norifumi; Suzuki, Masakazu

2013-04-01

Differences in drop size distribution (DSD) of leaf drips among tree species have been estimated and physically interpreted to clarify the leaf drip generation process. Leaf drip generation experiments for nine species were conducted in an indoor location without foliage vibration using an automatic mist spray. Broad-leaved species produced a similar DSD among species whose leaves had a matte surface and a second similar DSD among species whose leaves had a coated surface. The matte broad leaves produced a larger and wider range of DSDs than the coated broad leaves. Coated coniferous needles had a wider range of DSDs than the coated broad leaves and different DSDs were observed for different species. The species with shorter dense needles generated a larger DSD. The leaf drip diameter was calculated through the estimation of a state of equilibrium of a hanging drop on the leaves based on physical theory. The calculations indicated that the maximum diameter of leaf drips was determined by the contact angle, and the range of DSDs was determined by the variation in contact length and the contact diameter at the hanging points. The results revealed that leaf drip DSD changed due to variations in leaf hydrophobicity, leaf roughness, leaf geometry and leaf inclination among the different tree species. This study allows the modelization of throughfall DSD. Furthermore, it indicates the possibility of interpreting canopy water processes from canopy water storage to drainage through the contact angle and leaf drip DSD. The part of this study is published in Nanko et al. (2013, Agric. Forest. Meteorol. 169, 74-84).

Hydroxyapatite coating of titanium implants using hydroprocessing and evaluation of their osteoconductivity.

PubMed

Kuroda, Kensuke; Okido, Masazumi

2012-01-01

Many techniques for the surface modification of titanium and its alloys have been proposed from the viewpoint of improving bioactivity. This paper contains an overview of surface treatment methods, including coating with hydroxyapatite (HAp), an osteoconductive compound. There are two types of coating methods: pyroprocessing and hydroprocessing. In this paper, hydroprocessing for coating on the titanium substrate with HAp, carbonate apatite (CO(3)-Ap), a CO(3)-Ap/CaCO(3) composite, HAp/collagen, and a HAp/gelatin composite is outlined. Moreover, evaluation by implantation of surface-modified samples in rat tibiae is described.

Hydroxyapatite Coating of Titanium Implants Using Hydroprocessing and Evaluation of Their Osteoconductivity

PubMed Central

Kuroda, Kensuke; Okido, Masazumi

2012-01-01

Many techniques for the surface modification of titanium and its alloys have been proposed from the viewpoint of improving bioactivity. This paper contains an overview of surface treatment methods, including coating with hydroxyapatite (HAp), an osteoconductive compound. There are two types of coating methods: pyroprocessing and hydroprocessing. In this paper, hydroprocessing for coating on the titanium substrate with HAp, carbonate apatite (CO3–Ap), a CO3–Ap/CaCO3 composite, HAp/collagen, and a HAp/gelatin composite is outlined. Moreover, evaluation by implantation of surface-modified samples in rat tibiae is described. PMID:22400015

Ultrasound assisted deposition of silica coatings on titanium

NASA Astrophysics Data System (ADS)

Kaş, Recep; Ertaş, Fatma Sinem; Birer, Özgür

2012-10-01

We present a novel ultrasound assisted method for silica coating of titanium surfaces. The coatings are formed by “smashing” silica nanoparticles onto activated titanium surface in solution using intense ultrasonic field. Homogeneous silica coatings are formed by deposition of dense multiple layers of silica nanoparticles. Since the nanoparticles also grow during the reaction, the layers of the coatings have smaller particles on the substrate and larger particles towards the surface. The thickness of the coatings can be controlled with several experimental parameters. Silica layers with thickness over 200 nm are readily obtained.

Reducing Heat Gains and Cooling Loads Through Roof Structure Configurations of A House in Medan

NASA Astrophysics Data System (ADS)

Handayani Lubis, Irma; Donny Koerniawan, Mochamad

2018-05-01

Heat gains and heat losses through building surfaces are the main factors that determine the building’s cooling and heating loads. Roof as a building surface that has the most exposed area to the sun, contribute most of heat gains in the building. Therefore, the amount of solar heat gains on the roofs need to be minimized by roof structure configurations. This research aims to discover the optimization of roof structure configurations (coating material, structure material, inclination, overhang, and insulation) as one of passive design strategies that reduce heat gains and cooling loads of a house in Medan. The result showed that case four, white-painted metal roof combined with 45° roof pitched, 1.5m overhang, and addition of insulation, indicates the minimum heat gains production and the less cooling loads during clear sky day but not in the overcast sky condition. In conclusion, heat gains and cooling loads of a house in Medan could be diminished during clear sky day by the addition of roof coating with high reflectance low solar absorbtance, the slope roof, the extension of wider veranda, and the addition of insulation in the roof structure.

Thin film heater for removable volatile protecting coatings.

PubMed

Karim, Abid

2013-01-01

Freshly coated aluminum mirrors have excellent reflectivity at far ultraviolet wavelengths. However, reflectivity rapidly degrades when the mirror surfaces are exposed to atmosphere. In order to avoid this problem, freshly coated aluminum surface can be protected by over-coating of a removable volatile protecting coating. This protecting coating can be re-evaporated by controlled heating or by some other methods when required. This type of removable coating has immediate application in UV space astronomy. The purpose of this paper is to demonstrate the feasibility of re-evaporation of removable volatile Zn protecting coating using a NiCr thin film heater without affecting the reflection properties of Al mirror surfaces.

Method for welding beryllium

DOEpatents

Dixon, Raymond D.; Smith, Frank M.; O'Leary, Richard F.

1997-01-01

A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon.

Method for welding beryllium

DOEpatents

Dixon, R.D.; Smith, F.M.; O`Leary, R.F.

1997-04-01

A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon. 9 figs.

Method and coating composition for protecting and decontaminating surfaces

DOEpatents

Overhold, D C; Peterson, M D

1959-03-10

A protective coating useful in the decontamination of surfaces exposed to radioactive substances is described. This coating is placed on the surface before use and is soluble in water, allowing its easy removal in the event decontamination becomes necessary. Suitable coating compositions may be prepared by mixing a water soluble carbohydrate such as sucrose or dextrin, together with a hygroscopic agent such as calcium chloride or zinc chloride.

METHOD AND COATING COMPOSITION FOR PROTECTING AND DECONTAMINATING SURFACES

DOEpatents

Overhold, D.C.; Peterson, M.D.

1959-03-10

A protective coating useful in the decontamination of surfaces exposed to radioactive substances is presented. This coating is placed on the surface before use and is soluble in waters allowing its easy removal in the event decontamination becomes necessary. Suitable coating compositions may be prepared by mixing a water soluble carbohydrate such as sucrose or dextrin, together with a hygroscopic agent such as calcium chloride or zinc chloride.

Bioactive glass-chitosan composite coatings on PEEK: Effects of surface wettability and roughness on the interfacial fracture resistance and in vitro cell response

NASA Astrophysics Data System (ADS)

Hong, Wei; Guo, Fangwei; Chen, Jianwei; Wang, Xin; Zhao, Xiaofeng; Xiao, Ping

2018-05-01

To improve the osteointegration of polyetheretherketone (PEEK) spinal fusions, the 45S5 bioactive glass® (BG)-chitosan (CH) composite was used to coat the PEEK by a dip-coating method at room temperature. A robust bonding between the BG-CH composite coating and the PEEK was achieved by a combined surface treatment of sand blasting and acid etching. The effects of surface wettability and surface roughness on the adhesion of the BG-CH composite coating were characterized by fracture resistance (Gc), respectively, measured by four-point bending tests. Compared with the surface polar energy (wettability), the surface roughness (>3 μm) played a more important role for the increase in Gc values by means of crack shielding effect under the mixed mode stress. The maximum adhesion strength (σ) of the coatings on the modified PEEK measured by the tensile pull-off test was about 5.73 MPa. The in vitro biocompatibilities of PEEK, including cell adhesion, cell proliferation, differentiation, and bioactivity in the stimulated body fluid (SBF), were enhanced by the presence of BG-CH composite coatings, which also suggested that this composite coating method could provide an effective solution for the weak PEEK-bone integration.

Industrial surface coatings: Wood furniture and fixtures emission inventory development. Final report

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

Anex, R.P.; Lund, J.R.; Chang, D.P.Y.

1998-06-01

The purpose of this study is to update the methods for estimating emissions from the industrial coatings subcategory of wood furniture and fixtures. The wood furniture and fixture industry encompasses the manufacture of diverse products including cabinets, office furniture, store fixtures, and residential furniture. Specific objectives of this work are to: (1) estimate the amount of coating used in the industrial surface coating of wood furniture and fixtures; (2) develop emissions factors for each coating application category; (3) estimate variability of both coating use and emission factors; and (4) specify a source of information and method to revise and updatemore » the industrial coating of wood furniture and fixtures emission inventory.« less

Enhanced heat transfer surface for cast-in-bump-covered cooling surfaces and methods of enhancing heat transfer

DOEpatents

Chiu, Rong-Shi Paul; Hasz, Wayne Charles; Johnson, Robert Alan; Lee, Ching-Pang; Abuaf, Nesim

2002-01-01

An annular turbine shroud separates a hot gas path from a cooling plenum containing a cooling medium. Bumps are cast in the surface on the cooling side of the shroud. A surface coating overlies the cooling side surface of the shroud, including the bumps, and contains cooling enhancement material. The surface area ratio of the cooling side of the shroud with the bumps and coating is in excess of a surface area ratio of the cooling side surface with bumps without the coating to afford increased heat transfer across the element relative to the heat transfer across the element without the coating.

Surface characteristic of chemically converted graphene coated low carbon steel by electro spray coating method for polymer electrolyte membrane fuel cell bipolar plate.

PubMed

Kim, Jungsoo; Kim, Yang Do; Nam, Dae Geun

2013-05-01

Graphene was coated on low carbon steel (SS400) by electro spray coating method to improve its properties of corrosion resistance and contact resistance. Exfoliated graphite was made of the graphite by chemical treatment (Chemically Converted Graphene, CCG). CCG is distributed using dispersing agent, and low carbon steel was coated with diffuse graphene solution by electro spray coating method. The structure of the CCG was analyzed using XRD and the coating layer of surface was analyzed using SEM. Analysis showed that multi-layered graphite structure was destroyed and it was transformed in to fine layers graphene structure. And the result of SEM analysis on the surface and the cross section, graphene layer was uniformly formed with 3-5 microm thickness on the surface of substrate. Corrosion resistance test was applied in the corrosive solution which is similar to the polymer electrolyte membrane fuel cell (PEMFC) stack inside. And interfacial contact resistance (ICR) test was measured to simulate the internal operating conditions of PEMFC stack. As a result of measuring corrosion resistance and contact resistance, it could be confirmed that low carbon steel coated with CCG was revealed to be more effective in terms of its applicability as PEMFC bipolar plate.

Effects of treadmill inclination on electromyographic activity and hind limb kinematics in healthy hounds at a walk.

PubMed

Lauer, Susanne K; Hillman, Robert B; Li, Li; Hosgood, Giselle L

2009-05-01

To evaluate the effect of treadmill incline on muscle activity and joint range of motion (ROM) in hind limbs of dogs. 8 purpose-bred healthy adult hounds. Activities of the hamstring (semimembranosus, semitendinosus, and biceps femoris muscles), gluteal (superficial, middle, and deep gluteal muscles), and quadriceps (femoris, vastus lateralis, vastus intermedius, and vastus medialis muscles) muscle groups and hip and stifle joint ROM were measured with surface electrogoniometric and myographic sensors in hounds walking on a treadmill at 0.54 m/s at inclines of 5%, 0%, and -5% in random order. Mean electromyographic activities and mean ROMs at each inclination were compared for swing and stance phases. Treadmill inclination did not affect duration of the stance and swing phases or the whole stride. When treadmill inclination was increased from -5% to 5%, hip joint ROM increased and the degree of stifle joint extension decreased significantly. In the beginning of the stance phase, activity of the hamstring muscle group was significantly increased when walking at a 5% incline versus a 5% decline. In the end of the stance phase, that activity was significantly increased when walking at a 5% incline versus at a 5% decline or on a flat surface. Activity of the gluteal and quadriceps muscle groups was not affected when treadmill inclination changed. Treadmill inclination affected joint kinematics only slightly. Walking on a treadmill at a 5% incline had more potential to strengthen the hamstring muscle group than walking on a treadmill with a flat or declined surface.

Liquid Galvanic Coatings for Protection of Imbedded Metals

NASA Technical Reports Server (NTRS)

MacDowell, Louis G. (Inventor); Curran, Joseph J. (Inventor)

2003-01-01

Coating compositions and methods of their use are described herein for the reduction of corrosion in imbedded metal structures. The coatings are applied as liquids to an external surface of a substrate in which the metal structures are imbedded. The coatings are subsequently allowed to dry. The liquid applied coatings provide galvanic protection to the imbedded metal structures. Continued protection can be maintained with periodic reapplication of the coating compositions, as necessary, to maintain electrical continuity. Because the coatings may be applied using methods similar to standard paints, and because the coatings are applied to external surfaces of the substrates in which the metal structures are imbedded, the corresponding corrosion protection may be easily maintained. The coating compositions are particularly useful in the protection of metal-reinforced concrete.

Metallurgical coatings and thin films; Proceedings of the International Conference, 18th, San Diego, CA, Apr. 22-26, 1991. Vols. 1 & 2

NASA Technical Reports Server (NTRS)

Mcguire, Gary E. (Editor); Mcintyre, Dale C. (Editor); Hofmann, Siegfried (Editor)

1991-01-01

A conference on metallurgical coatings and thin films produced papers in the areas of coatings for use at high temperatures; hard coatings and deposition technologies; diamonds and related materials; tribological coatings/surface modifications; thin films for microelectronics and high temperature superconductors; optical coatings, film characterization, magneto-optics, and guided waves; and methods for characterizing films and modified surfaces.

Hollow Rodlike MgF2 with an Ultralow Refractive Index for the Preparation of Multifunctional Antireflective Coatings.

PubMed

Bao, Lei; Ji, Zihan; Wang, Hongning; Chen, Ruoyu

2017-06-27

Antireflective coatings with superhydrophobic, self-cleaning, and wide-spectrum high-transmittance properties and good mechanical strength have important practical value. In this research, hollow nanorod-like MgF 2 sols with different void volumes were prepared by a template-free solvothermal method to further obtain hollow nanorod-like MgF 2 crystals with an ultralow refractive index of 1.14. Besides, a MgF 2 coating with an adjustable refractive index of 1.10-1.35 was also prepared by the template-free solvothermal method. Then through the combination of base/acid two-step-catalyzed TEOS and hydroxyl modification on the surface of nanosilica spheres, the SiO 2 coating with good mechanical strength, a flat surface, and a refractive index of 1.30-1.45 was obtained. Double-layer broadband antireflective coatings with an average transmittance of 99.6% at 400-1400 nm were designed using the relevant optical theory. After the coating thickness was optimized by the dip-coating method, the double-layer antireflective coatings, whose parameters were consistent with those designed by the theory, were obtained. The bottom layer was a SiO 2 coating with a refractive index of 1.34 and a thickness of 155 nm, and the top layer was a hollow rodlike MgF 2 coating with a refractive index of 1.10 and a thickness of 165 nm. The average transmittance of the obtained MgF 2 -SiO 2 antireflective coatings was 99.1% at 400-1400 nm, which was close to the theoretical value. The hydrophobic angle of the coating surface reached 119° at first, and the angle further reached 152° after conducting surface modification by PFOTES. In addition, because the porosity of the coating surface was only 10.7%, the pencil hardness of the coating surface was 5 H and the critical load Lc was 27.05 N. In summary, the obtained antireflective coatings possessed superhydrophobic, self-cleaning, and wide-spectrum high-transmittance properties and good mechanical strength.

Optoelectronic properties and interfacial durability of CNT and ITO on boro-silicate glass and PET substrates with nano- and heterostructural aspects

NASA Astrophysics Data System (ADS)

Park, Joung-Man; Wang, Zuo-Jia; Kwon, Dong-Jun; DeVries, Lawrence

2011-02-01

Nano- and hetero-structures of carbon nanotube (CNT) and indium tin oxide (ITO) can control significantly piezoelectric and optoelectronic properties in Microelectromechanical Systems (MEMS) as sensing and actuator under cyclic loading. Optimized preparing conditions were obtained for multi-functional purpose of the specimen by obtaining the best dispersion and turbidity in the solution. Optical transmittance and electrical properties were investigated for CNT and ITO dipping and spraying coating on boro-silicate glass and polyethylene terephthalate (PET) substrates by electrical resistance measurement under cyclic loading and wettability test. Uniform dip-coating was performed using Wilhelmy plate method due to its simple and convenience. Spraying coating was applied to the specimen additionally. The change in the electrical resistance and optical properties of coated layer were mainly dependent upon the number of dip-coating, the concentration of CNT and ITO solutions, and the surface treatment condition. Electric properties of coating layers were measured using four-point probe method, and surface resistance was calculated using a dual configuration method. Optical transmittance of CNT and ITO coated PET film was also evaluated using UV spectrum. Surface energy and their hydrophilic and hydrophobic properties of CNT and ITO coated substrates were investigated by wettability test via static and dynamic contact angle measurements. As the elapsing time of cyclic loading passed, the stability of surface resistance and thus comparative interfacial adhesion between coated layer and substrates was evaluated to compare the thermodynamic work of adhesion, Wa. As dip-coating number increased, surface resistance of coated CNT decreased, whereas the transmittance decreased step-by-step due to the thicker CNT and ITO networked layer. Nano- and heterostructural effects of CNT and ITO solution on the optical and electrical effects have been studied continuously.

Prevention of corrosion with polyaniline

NASA Technical Reports Server (NTRS)

Ahmad, Naseer (Inventor); MacDiarmid, Alan G. (Inventor)

1997-01-01

Methods for improving the corrosion inhibition of a metal or metal alloy substrate surface are provided wherein the substrate surface is coated with a polyaniline film. The polyaniline film coating is applied by contacting the substrate surface with a solution of polyaniline. The polyaniline is dissolved in an appropriate organic solvent and the solvent is allowed to evaporate from the substrate surface yielding the polyaniline film coating.

Method for Fabricating Soft Tissue Implants with Microscopic Surface Roughness

NASA Technical Reports Server (NTRS)

Banks, Bruce A. (Inventor); Rutledge, Sharon K. (Inventor)

1999-01-01

A method for fabricating soft tissue implants using a mold. The cavity surface of an initially untextured mold. made of an organic material such as epoxy. is given a thin film coating of material that has pinholes and is resistant to atomic particle bombardment. The mold cavity surface is then subjected to atomic particle bombardment, such as when placed in an isotropic atomic oxygen environment. Microscopic depressions in the mold cavity surface are created at the pinhole sites on the thin film coating. The thin film coating is removed and the mold is then used to cast the soft tissue implant. The thin film coating having pinholes may be created by chilling the mold below the dew point such that water vapor condenses upon it; distributing particles, that can partially dissolve and become attached to the mold cavity surface, onto the mold cavity surface; removing the layer of condensate, such as by evaporation; applying the thin film coating over the entire mold surface; and, finally removing the particles, such as by dissolving or brushing it off. Pinholes are created in the thin film coating at the sites previously occupied by the particles.

Analytical Method Used to Calculate Pile Foundations with the Widening Up on a Horizontal Static Impact

NASA Astrophysics Data System (ADS)

Kupchikova, N. V.; Kurbatskiy, E. N.

2017-11-01

This paper presents a methodology for the analytical research solutions for the work pile foundations with surface broadening and inclined side faces in the ground array, based on the properties of Fourier transform of finite functions. The comparative analysis of the calculation results using the suggested method for prismatic piles, piles with surface broadening prismatic with precast piles and end walls with precast wedges on the surface is described.

Method for measuring surface shear stress magnitude and direction using liquid crystal coatings

NASA Technical Reports Server (NTRS)

Reda, Daniel C. (Inventor)

1995-01-01

A method is provided for determining surface shear magnitude and direction at every point on a surface. The surface is covered with a shear stress sensitive liquid crystal coating and illuminated by white light from a normal direction. A video camera is positioned at an oblique angle above the surface to observe the color of the liquid crystal at that angle. The shear magnitude and direction are derived from the color information. A method of calibrating the device is also provided.

Development of new maskless manufacturing method for anti-reflection structure and application to large-area lens with curved surface

NASA Astrophysics Data System (ADS)

Yamamoto, Kazuya; Takaoka, Toshimitsu; Fukui, Hidetoshi; Haruta, Yasuyuki; Yamashita, Tomoya; Kitagawa, Seiichiro

2016-03-01

In general, thin-film coating process is widely applied on optical lens surface as anti-reflection function. In normal production process, at first lens is manufactured by molding, then anti-reflection is added by thin-film coating. In recent years, instead of thin-film coating, sub-wavelength structures adding on surface of molding die are widely studied and development to keep anti-reflection performance. As merits, applying sub-wavelength structure, coating process becomes unnecessary and it is possible to reduce man-hour costs. In addition to cost merit, these are some technical advantages on this study. Adhesion of coating depends on material of plastic, and it is impossible to apply anti-reflection function on arbitrary surface. Sub-wavelength structure can solve both problems. Manufacturing method of anti-reflection structure can be divided into two types mainly. One method is with the resist patterning, and the other is mask-less method that does not require patterning. What we have developed is new mask-less method which is no need for resist patterning and possible to impart an anti-reflection structure to large area and curved lens surface, and can be expected to apply to various market segments. We report developed technique and characteristics of production lens.

Patterned structures of graphene and graphitic carbon and methods for their manufacture

DOEpatents

Polsky, Ronen; Xiao, Xiaoyin; Burckel, David Bruce; Wheeler, David R.; Brozik, Susan M.; Beechem, Thomas Edwin

2017-01-03

A patterned graphene or graphitic body is produced by providing a three-dimensionally patterned carbonaceous body; coating the body with a catalytic metal whereby is formed a coating having an inner surface proximal the body and an outer surface distal the body; and annealing the coated body under time and temperature conditions effective to form a graphene or graphitic layer on the outer surface of the catalytic metal coating.

Patterned structures of graphene and graphitic carbon and methods for their manufacture

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

Polsky, Ronen; Xiao, Xiaoyin; Burckel, David Bruce

A patterned graphene or graphitic body is produced by providing a three-dimensionally patterned carbonaceous body; coating the body with a catalytic metal whereby is formed a coating having an inner surface proximal the body and an outer surface distal the body; and annealing the coated body under time and temperature conditions effective to form a graphene or graphitic layer on the outer surface of the catalytic metal coating.

Effect of different methods of preliminary surface treatment and magnetron sputtering on the adhesion of Si coatings

NASA Astrophysics Data System (ADS)

Borisov, D. P.; Slabodchikov, V. A.; Kuznetsov, V. M.

2017-05-01

The paper presents research results on the adhesion of Si coatings deposited by magnetron sputtering on NiTi substrates after preliminary surface treatment (cleaning and activation) with low-energy ion beams and gas discharge plasma. The adhesion properties of the coatings obtained by two methods are analyzed and compared using data of scratch and spherical abrasion tests.

Exponentially varying viscosity of magnetohydrodynamic mixed convection Eyring-Powell nanofluid flow over an inclined surface

NASA Astrophysics Data System (ADS)

Khan, Imad; Fatima, Sumreen; Malik, M. Y.; Salahuddin, T.

2018-03-01

This paper explores the theoretical study of the steady incompressible two dimensional MHD boundary layer flow of Eyring-Powell nanofluid over an inclined surface. The fluid is considered to be electrically conducting and the viscosity of the fluid is assumed to be varying exponentially. The governing partial differential equations (PDE's) are reduced into ordinary differential equations (ODE's) by applying similarity approach. The resulting ordinary differential equations are solved successfully by using Homotopy analysis method. The impact of pertinent parameters on velocity, concentration and temperature profiles are examined through graphs and tables. Also coefficient of skin friction, Sherwood and Nusselt numbers are illustrated in tabular and graphical form.

Clinically acceptable agreement between the ViMove wireless motion sensor system and the Vicon motion capture system when measuring lumbar region inclination motion in the sagittal and coronal planes.

PubMed

Mjøsund, Hanne Leirbekk; Boyle, Eleanor; Kjaer, Per; Mieritz, Rune Mygind; Skallgård, Tue; Kent, Peter

2017-03-21

Wireless, wearable, inertial motion sensor technology introduces new possibilities for monitoring spinal motion and pain in people during their daily activities of work, rest and play. There are many types of these wireless devices currently available but the precision in measurement and the magnitude of measurement error from such devices is often unknown. This study investigated the concurrent validity of one inertial motion sensor system (ViMove) for its ability to measure lumbar inclination motion, compared with the Vicon motion capture system. To mimic the variability of movement patterns in a clinical population, a sample of 34 people were included - 18 with low back pain and 16 without low back pain. ViMove sensors were attached to each participant's skin at spinal levels T12 and S2, and Vicon surface markers were attached to the ViMove sensors. Three repetitions of end-range flexion inclination, extension inclination and lateral flexion inclination to both sides while standing were measured by both systems concurrently with short rest periods in between. Measurement agreement through the whole movement range was analysed using a multilevel mixed-effects regression model to calculate the root mean squared errors and the limits of agreement were calculated using the Bland Altman method. We calculated root mean squared errors (standard deviation) of 1.82° (±1.00°) in flexion inclination, 0.71° (±0.34°) in extension inclination, 0.77° (±0.24°) in right lateral flexion inclination and 0.98° (±0.69°) in left lateral flexion inclination. 95% limits of agreement ranged between -3.86° and 4.69° in flexion inclination, -2.15° and 1.91° in extension inclination, -2.37° and 2.05° in right lateral flexion inclination and -3.11° and 2.96° in left lateral flexion inclination. We found a clinically acceptable level of agreement between these two methods for measuring standing lumbar inclination motion in these two cardinal movement planes. Further research should investigate the ViMove system's ability to measure lumbar motion in more complex 3D functional movements and to measure changes of movement patterns related to treatment effects.

Method of identifying defective particle coatings

DOEpatents

Cohen, Mark E.; Whiting, Carlton D.

1986-01-01

A method for identifying coated particles having defective coatings desig to retain therewithin a build-up of gaseous materials including: (a) Pulling a vacuum on the particles; (b) Backfilling the particles at atmospheric pressure with a liquid capable of wetting the exterior surface of the coated particles, said liquid being a compound which includes an element having an atomic number higher than the highest atomic number of any element in the composition which forms the exterior surface of the particle coating; (c) Drying the particles; and (d) Radiographing the particles. By television monitoring, examination of the radiographs is substantially enhanced.

New configuration for efficient and durable copper coating on the outer surface of a tube

DOE PAGES

Ahmad, Irfan; Chapman, Steven F.; Velas, Katherine M.; ...

2017-03-27

A well-adhered copper coating on stainless steel power coupler parts is required in superconducting radio frequency (SRF) accelerators. Radio frequency power coupler parts are complex, tubelike stainless steel structures, which require copper coating on their outer and inner surfaces. Conventional copper electroplating sometimes produces films with inadequate adhesion strength for SRF applications. Electroplating also requires a thin nickel strike layer under the copper coating, whose magnetic properties can be detrimental to SRF applications. Coaxial energetic deposition (CED) and sputtering methods have demonstrated efficient conformal coating on the inner surfaces of tubes but coating the outer surface of a tube ismore » challenging because these coating methods are line of sight. When the substrate is off axis and the plasma source is on axis, only a small section of the substrate’s outer surface is exposed to the source cathode. The conventional approach is to rotate the tube to achieve uniformity across the outer surface. This method results in poor film thickness uniformity and wastes most of the source plasma. Alameda Applied Sciences Corporation (AASC) has developed a novel configuration called hollow external cathode CED (HEC-CED) to overcome these issues. HEC-CED produces a film with uniform thickness and efficiently uses all eroded source material. Furthermore, the Cu film deposited on the outside of a stainless steel tube using the new HEC-CED configuration survived a high pressure water rinse adhesion test. HEC-CED can be used to coat the outside of any cylindrical structure.« less

New configuration for efficient and durable copper coating on the outer surface of a tube

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

Ahmad, Irfan; Chapman, Steven F.; Velas, Katherine M.

A well-adhered copper coating on stainless steel power coupler parts is required in superconducting radio frequency (SRF) accelerators. Radio frequency power coupler parts are complex, tubelike stainless steel structures, which require copper coating on their outer and inner surfaces. Conventional copper electroplating sometimes produces films with inadequate adhesion strength for SRF applications. Electroplating also requires a thin nickel strike layer under the copper coating, whose magnetic properties can be detrimental to SRF applications. Coaxial energetic deposition (CED) and sputtering methods have demonstrated efficient conformal coating on the inner surfaces of tubes but coating the outer surface of a tube ismore » challenging because these coating methods are line of sight. When the substrate is off axis and the plasma source is on axis, only a small section of the substrate’s outer surface is exposed to the source cathode. The conventional approach is to rotate the tube to achieve uniformity across the outer surface. This method results in poor film thickness uniformity and wastes most of the source plasma. Alameda Applied Sciences Corporation (AASC) has developed a novel configuration called hollow external cathode CED (HEC-CED) to overcome these issues. HEC-CED produces a film with uniform thickness and efficiently uses all eroded source material. Furthermore, the Cu film deposited on the outside of a stainless steel tube using the new HEC-CED configuration survived a high pressure water rinse adhesion test. HEC-CED can be used to coat the outside of any cylindrical structure.« less

Methods of Antimicrobial Coating of Diverse Materials

NASA Technical Reports Server (NTRS)

Akse, James R.; Holtsnider, John T.; Kliestik, Helen

2011-01-01

Methods of coating diverse substrate materials with antimicrobial agents have been developed. Originally intended to reduce health risks to astronauts posed by pathogenic microorganisms that can grow on surfaces in spacecraft, these methods could also be used on Earth for example, to ensure sterility of surgical inserts and other medical equipment. The methods involve, generally, chemical preparation of substrate surfaces to enable attachment of antimicrobial molecules to the substrate surfaces via covalent bonds. Substrate materials that have been treated successfully include aluminum, glass, a corrosion-resistant nickel alloy, stainless steel, titanium, and poly(tetrafluoroethylene). Antimicrobial agents that have been successfully immobilized include antibiotics, enzymes, bacteriocins, bactericides, and fungicides. A variety of linkage chem istries were employed. Activity of antimicrobial coatings against gram-positive bacteria, gram-negative bacteria, and fungi was demonstrated. Results of investigations indicate that the most suitable combination of antimicrobial agent, substrate, and coating method depends upon the intended application.

Rolling viscous drops on a non-wettable surface containing both micro- and macro-scale roughness

NASA Astrophysics Data System (ADS)

Abolghasemibizaki, Mehran; Robertson, Connor J.; Fergusson, Christian P.; McMasters, Robert L.; Mohammadi, Reza

2018-02-01

It has previously been shown that when a liquid drop of high viscosity is placed on a non-wettable inclined surface, it rolls down at a constant descent velocity determined by the balance between viscous dissipation and the reduction rate of its gravitational potential energy. Since increasing the roughness of the surface boosts its non-wetting property, the drop should move faster on a surface structured with macrotextures (ribbed surface). Such a surface was obtained from a superhydrophobic soot coating on a solid specimen printed with an extruder-type 3D printer. The sample became superoleophobic after a functionalization process. The descent velocity of glycerol drops of different radii was then measured on the prepared surface for varied tilting angles. Our data show that the drops roll down on the ribbed surface approximately 27% faster (along the ridges) than on the macroscopically smooth counterpart. This faster velocity demonstrates that ribbed surfaces can be promising candidates for drag-reduction and self-cleaning applications. Moreover, we came up with a modified scaling model to predict the descent velocity of viscous rolling drops more accurately than what has previously been reported in the literature.

Influence of nano-structured alumina coating on shear bond strength between Y-TZP ceramic and various dual-cured resin cements.

PubMed

Lee, Jung-Jin; Choi, Jung-Yun; Seo, Jae-Min

2017-04-01

The purpose of this study was to evaluate the effect of nano-structured alumina surface coating on shear bond strength between Y-TZP ceramic and various dual-cured resin cements. A total of 90 disk-shaped zirconia specimens (HASS CO., Gangneung, Korea) were divided into three groups by surface treatment method: (1) airborne particle abrasion, (2) tribochemicalsilica coating, and (3) nano-structured alumina coating. Each group was categorized into three subgroups of ten specimens and bonded with three different types of dual-cured resin cements. After thermocycling, shear bond strength was measured and failure modes were observed through FE-SEM. Two-way ANOVA and the Tukey's HSD test were performed to determine the effects of surface treatment method and type of cement on bond strength ( P <.05). To confirm the correlation of surface treatment and failure mode, the Chi-square test was used. Groups treated with the nanostructured alumina coating showed significantly higher shear bond strength compared to other groups treated with airborne particle abrasion or tribochemical silica coating. Clearfil SA Luting showed a significantly higher shear bond strength compared to RelyX ARC and RelyX Unicem. The cohesive failure mode was observed to be dominant in the groups treated with nano-structured alumina coating, while the adhesive failure mode was prevalent in the groups treated with either airborne particle abrasion or tribochemical silica coating. Nano-structured alumina coating is an effective zirconia surface treatment method for enhancing the bond strength between Y-TZP ceramic and various dual-cured resin cements.

Design of Aerosol Coating Reactors: Precursor Injection

PubMed Central

Buesser, Beat; Pratsinis, Sotiris E.

2013-01-01

Particles are coated with thin shells to facilitate their processing and incorporation into liquid or solid matrixes without altering core particle properties (coloristic, magnetic, etc.). Here, computational fluid and particle dynamics are combined to investigate the geometry of an aerosol reactor for continuous coating of freshly-made titanium dioxide core nanoparticles with nanothin silica shells by injection of hexamethyldisiloxane (HMDSO) vapor downstream of TiO2 particle formation. The focus is on the influence of HMDSO vapor jet number and direction in terms of azimuth and inclination jet angles on process temperature and coated particle characteristics (shell thickness and fraction of uncoated particles). Rapid and homogeneous mixing of core particle aerosol and coating precursor vapor facilitates synthesis of core-shell nanoparticles with uniform shell thickness and high coating efficiency (minimal uncoated core and free coating particles). PMID:23658471

Evaluation of the surface properties of PTFE foam coating filter media using XPS and contact angle measurements

NASA Astrophysics Data System (ADS)

Park, Byung Hyun; Lee, Myong-Hwa; Kim, Sang Bum; Jo, Young Min

2011-02-01

A newly developed PTFE foam coating filter was developed which can be used for hot gas cleaning at temperatures up to 250 °C. The emulsion-type PTFE was coated onto a woven glass fiber using a foam coating method. The filter surface was closely examined using X-ray photoelectron spectroscopy (XPS) and contact angle measurements. The XPS results were used to determine the binding force between the carbon and fluorine of PTFE, which imparts coating stability to the filter medium. More than 95% of the bonds of the PTFE foam coating filter were between carbon and fluorine, and this filter demonstrated excellent hydrophobic and good oleophobic properties at the same time. The contact angles of liquid droplets on the filter surface were used to predict the potential wetability of the filter against water or oil. In addition, the very low surface free energy of the filter medium, which was evaluated using the Owens-Wendt method, demonstrates a very stable surface and a high de-dusting quality.

Quantitation of Surface Coating on Nanoparticles Using Thermogravimetric Analysis.

PubMed

Dongargaonkar, Alpana A; Clogston, Jeffrey D

2018-01-01

Nanoparticles are critical components in nanomedicine and nanotherapeutic applications. Some nanoparticles, such as metallic nanoparticles, consist of a surface coating or surface modification to aid in its dispersion and stability. This surface coating may affect the behavior of nanoparticles in a biological environment, thus it is important to measure. Thermogravimetric analysis (TGA) can be used to determine the amount of coating on the surface of the nanoparticle. TGA experiments run under inert atmosphere can also be used to determine residual metal content present in the sample. In this chapter, the TGA technique and experimental method are described.

Control of hydroxyapatite coating by self-assembled monolayers on titanium and improvement of osteoblast adhesion.

PubMed

Shen, Juan; Qi, Yongcheng; Jin, Bo; Wang, Xiaoyan; Hu, Yamin; Jiang, Qiying

2017-01-01

Self-assembly technique was applied to introduce functional groups and form hydroxyl-, amine-, and carboxyl-terminal self-assembled monolayers (SAMs). The SAMs were grafted onto titanium substrates to obtain a molecularly smooth functional surface. Subsequent hydrothermal crystal growth formed homogeneous and crack-free crystalline hydroxyapatite (HA) coatings on these substrates. AFM and XPS were used to characterize the SAM surfaces, and XRD, SEM, and TEM were used to characterize the HA coatings. Results show that highly crystalline, dense, and oriented HA coatings can be formed on the OH-, NH 2 -, and COOH-SAM surfaces. The SAM surface with -COOH exhibited stronger nucleating ability than that with -OH and -NH 2 . The nucleation and growth processes of HA coatings were effectively controlled by varying reaction time, pH, and temperature. By using this method, highly crystalline, dense, and adherent HA coatings were obtained. In addition, in vitro cell evaluation demonstrated that HA coatings improved cell adhesion as compared with pristine titanium substrate. The proposed method is considerably effective in introducing the HA coatings on titanium surfaces for various biomedical applications and further usage in other industries. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 124-135, 2017. © 2015 Wiley Periodicals, Inc.

Enhancing the Stiffness of Electrospun Nanofiber Scaffolds with Controlled Surface Coating and Mineralization

PubMed Central

Liu, Wenying; Yeh, Yi-Chun; Lipner, Justin; Xie, Jingwei; Sung, Hsing-Wen; Thomopoulos, Stavros; Xia, Younan

2011-01-01

A new method was developed to coat hydroxyapatite (HAp) onto electrospun poly(lactic-co-glycolic acid) (PLGA) nanofibers for tendon-to-bone insertion site repair applications. Prior to mineralization, chitosan and heparin were covalently immobilized onto the surface of the fibers to accelerate the nucleation of bone-like HAp crystals. Uniform coatings of HAp were obtained by immersing the nanofiber scaffolds into a modified 10 times concentrated simulated body fluid (m10SBF) for different periods of time. The new method resulted in thicker and denser coatings of mineral on the fibers compared to previously reported methods. Scanning electron microscopy measurements confirmed the formation of nanoscale HAp particles on the fibers. Mechanical property assessment demonstrated higher stiffness with respect to previous coating methods. A combination of the nanoscale fibrous structure and bone-like mineral coating could mimic the structure, composition, and function of mineralized tissues. PMID:21710996

Effect of Seat Surface Inclination on Postural Stability and forward Reaching Efficiency in Children with Spastic Cerebral Palsy

ERIC Educational Resources Information Center

Cherng, Rong-Ju; Lin, Hui-Chen; Ju, Yun-Huei; Ho, Chin-Shan

2009-01-01

The purpose of this study was to examine the effect of seat surface inclination on postural stability and forward reaching efficiency in 10 children with spastic cerebral palsy (CP) and 16 typically developing (TD) children. The children performed a static sitting and a forward reaching task while sitting on a height- and inclination-adjustable…

Systems and methods for coating conduit interior surfaces utilizing a thermal spray gun with extension arm

DOEpatents

Moore, Karen A.; Zatorski, Raymond A.

2005-07-12

Systems and methods for applying a coating to an interior surface of a conduit. In one embodiment, a spray gun configured to apply a coating is attached to an extension arm which may be inserted into the bore of a pipe. The spray gun may be a thermal spray gun adapted to apply a powder coating. An evacuation system may be used to provide a volume area of reduced air pressure for drawing overspray out of the pipe interior during coating. The extension arm as well as the spray gun may be cooled to maintain a consistent temperature in the system, allowing for more consistent coating.

Methods for coating conduit interior surfaces utilizing a thermal spray gun with extension arm

DOEpatents

Moore, Karen A.; Zatorski, Raymond A.

2007-10-02

Systems and methods for applying a coating to an interior surface of a conduit. In one embodiment, a spray gun configured to apply a coating is attached to an extension arm which may be inserted into the bore of a pipe. The spray gun may be a thermal spray gun adapted to apply a powder coating. An evacuation system may be used to provide a volume area of reduced air pressure for drawing overspray out of the pipe interior during coating. The extension arm as well as the spray gun may be cooled to maintain a consistent temperature in the system, allowing for more consistent coating.

Detailed statistical contact angle analyses; "slow moving" drops on inclining silicon-oxide surfaces.

PubMed

Schmitt, M; Groß, K; Grub, J; Heib, F

2015-06-01

Contact angle determination by sessile drop technique is essential to characterise surface properties in science and in industry. Different specific angles can be observed on every solid which are correlated with the advancing or the receding of the triple line. Different procedures and definitions for the determination of specific angles exist which are often not comprehensible or reproducible. Therefore one of the most important things in this area is to build standard, reproducible and valid methods for determining advancing/receding contact angles. This contribution introduces novel techniques to analyse dynamic contact angle measurements (sessile drop) in detail which are applicable for axisymmetric and non-axisymmetric drops. Not only the recently presented fit solution by sigmoid function and the independent analysis of the different parameters (inclination, contact angle, velocity of the triple point) but also the dependent analysis will be firstly explained in detail. These approaches lead to contact angle data and different access on specific contact angles which are independent from "user-skills" and subjectivity of the operator. As example the motion behaviour of droplets on flat silicon-oxide surfaces after different surface treatments is dynamically measured by sessile drop technique when inclining the sample plate. The triple points, the inclination angles, the downhill (advancing motion) and the uphill angles (receding motion) obtained by high-precision drop shape analysis are independently and dependently statistically analysed. Due to the small covered distance for the dependent analysis (<0.4mm) and the dominance of counted events with small velocity the measurements are less influenced by motion dynamics and the procedure can be called "slow moving" analysis. The presented procedures as performed are especially sensitive to the range which reaches from the static to the "slow moving" dynamic contact angle determination. They are characterised by small deviations of the computed values. Additional to the detailed introduction of this novel analytical approaches plus fit solution special motion relations for the drop on inclined surfaces and detailed relations about the reactivity of the freshly cleaned silicon wafer surface resulting in acceleration behaviour (reactive de-wetting) are presented. Copyright © 2014 Elsevier Inc. All rights reserved.

Durable hydrophobic coating composition for metallic surfaces and method for the preparation of the composition

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

Liu, Jiong

A durable hydrophobic coating composition containing fluorinated silanes for metallic surfaces, such as stainless steel surfaces. The composition includes at least one fluorine-containing silane compound, at least one phosphorus-containing silane compound, and at least one hydrolysable compound. This coating is suitable for condenser tubes, among other applications, to promote dropwise condensation.

Facile preparation of superhydrophobic surfaces based on metal oxide nanoparticles

NASA Astrophysics Data System (ADS)

Bao, Xue-Mei; Cui, Jin-Feng; Sun, Han-Xue; Liang, Wei-Dong; Zhu, Zhao-Qi; An, Jin; Yang, Bao-Ping; La, Pei-Qing; Li, An

2014-06-01

A novel method for fabrication of superhydrophobic surfaces was developed by facile coating various metal oxide nanoparticles, including ZnO, Al2O3 and Fe3O4, on various substrates followed by treatment with polydimethylsiloxane (PDMS) via chemical vapor deposition (CVD) method. Using ZnO nanoparticles as a model, the changes in the surface chemical composition and crystalline structures of the metal oxide nanoparticles by PDMS treatment were investigated by X-ray photoelectron spectroscopy (XPS), X-ray powder diffraction (XRD) and Fourier transform infrared (FTIR) analysis. The results show that the combination of the improved surface roughness generated from of the nanoparticles aggregation with the low surface-energy of silicon-coating originated from the thermal pyrolysis of PDMS would be responsible for the surface superhydrophobicity. By a simple dip-coating method, we show that the metal oxide nanoparticles can be easily coated onto the surfaces of various textural and dimensional substrates, including glass slide, paper, fabric or sponge, for preparation of superhydrophobic surfaces for different purpose. The present strategy may provide an inexpensive and new route to surperhydrophobic surfaces, which would be of technological significance for various practical applications especially for separation of oils or organic contaminates from water.

Degradation of nonmodified and rhodium modified aluminide coating deposited on CMSX 4 superalloy.

PubMed

Zagula-Yavorska, Maryana; Wierzbińska, Małgorzata; Gancarczyk, Kamil; Sieniawski, Jan

2016-07-01

The Ni-base superalloy CMSX 4 used in the turbine blades of aircraft engines was coated with rhodium layer (0.5-μm thick). Next coated CMSX 4 superalloy was aluminized by the CVD method. The rhodium modified aluminide coating and nonmodified aluminide coating were oxidized at 1100°C at the air atmosphere. The rhodium modified aluminide coating showed about twice better oxidation resistance than the nonmodified one. The spallation equal 62% of the total area was observed on the surface of the nonmodified coating whereas only 36% spallation area was observed on the surface of the rhodium modified aluminide coating after the oxidation test. The oxide layer formed on the surface of the nonmodified coating was composed of nonprotective (Ni,Cr)Al2 O4 and (Ni,Cr)O phases. Aluminium in the coating reacts with oxygen, forming a protective α-Al2 O3 oxide on the surface of the rhodium modified aluminide coating. When the oxide cracks and spalls due to oxidation, additional aluminium from the coating diffuses to the surface to form the oxide. The presence of protective Al2 O3 oxide on the surface of the rhodium modified aluminide coating slows coating degradation. Therefore, rhodium modified aluminide coating has better oxidation resistance than the nonmodified one. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

Synchronous scan-projection lithography on overall circumference of fine pipes with a diameter of 2 mm

NASA Astrophysics Data System (ADS)

Horiuchi, Toshiyuki; Furuhata, Takahiro; Muro, Hideyuki

2016-06-01

The scan-projection exposure of small-diameter pipe surfaces was investigated using a newly developed prototype exposure system. It is necessary to secure a very large depth of focus for printing thick resist patterns on round pipe surfaces with a roughness larger than that of semiconductor wafers. For this reason, a camera lens with a low numerical aperture of 0.089 was used as a projection lens, and the momentary exposure area was limited by a narrow slit with a width of 800 µm. Thus, patterns on a flat reticle were replicated on a pipe surface by linearly moving the reticle and rotating the pipe synchronously. By using a reticle with inclined line-and-space patterns, helical patterns with a width of 30 µm were successfully replicated on stainless-steel pipes with an outer diameter of 2 mm and coated with a 10-µm-thick negative resist. The patterns replicated at the start and stop edges were smoothly stitched seamlessly.

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

NASA Technical Reports Server (NTRS)

Hofmann, Douglas (Inventor)

2015-01-01

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

Droplet sliding on inclined superhydrophobic surfaces: the effect of anisotropic contact line

NASA Astrophysics Data System (ADS)

Jiang, Youhua; Cao, Lile; Guo, Zongqi; Choi, Chang-Hwan

2017-11-01

Although the effects of solid structures on droplet retention on superhydrophobic surfaces have been studied extensively, the investigation has been restricted to the sessile droplets on horizontal surfaces where the contact line motions are axisymmetric or isotropic (either advancing or receding). In the droplet retention on inclined surfaces, the contact line motions are asymmetric or anisotropic; the advancing and receding motions coexist. In this study, we investigate the correlation between the droplet boundary pinning and the surface morphology on inclined superhydrophobic surfaces. The evolution of the droplet contact angle and width show contrary behaviors between pillar- and pore-structured surfaces due to the distinctive microscopic contact line motions. Therefore, the visualizations of the contact line motions at different locations of the boundary on inclined superhydrophobic surfaces are performed and the averaged contact line density of the boundary is quantified. The result shows that the droplet retentive force monotonously increase with the increase in contact line density, regardless of the surface morphological types, dimensions, or the direction of contact line motion (advancing, receding, or both). The result indicates that the droplet retentive force on superhydrophobic surfaces is mainly determined by the contact line density, regardless of the isotropy of the contact line.

Polyacrylamide brush coatings preventing microbial adhesion to silicone rubber.

PubMed

Fundeanu, Irina; van der Mei, Henny C; Schouten, Arend J; Busscher, Henk J

2008-07-15

Silicone rubber is a frequently used biomaterial in biomedical devices and implants, yet highly prone to microbial adhesion and the development of a biomaterial-centered infection. Effective coating of silicone rubber to discourage microbial adhesion has thus far been impossible due to the hydrophobic character of its surface, surface deterioration upon treatment and instability of coatings under physiological conditions. Here we present a method to successfully grow polyacrylamide (PAAm) brushes from silicone rubber surfaces after removal of low molecular weight organic molecules (LMWOM), such as silane oligomers. PAAm brush coating did not cause any surface deterioration and discouraged microbial adhesion, even after 1-month exposure to physiological fluids. The method presented opens many new avenues for the use of silicone rubber as a biomaterial, without the risk of developing a biomaterial-centered infection.

Characterisation of a grooved heat pipe with an anodised surface

NASA Astrophysics Data System (ADS)

Solomon, A. Brusly; Ram Kumar, A. M.; Ramachandran, K.; Pillai, B. C.; Senthil Kumar, C.; Sharifpur, Mohsen; Meyer, Josua P.

2017-03-01

A grooved heat pipe (GHP) is an important device for managing heat in space applications such as satellites and space stations, as it works efficiently in the absence of gravity. Apart from the above application, axial GHPs are used in many applications, such as electronic cooling units for temperature control and permafrost cooling. Improving the performance of GHPs is essential for better cooling and thermal management. In the present study, the effect of anodization on the heat transfer characteristics of a GHP is studied with R600a as a working fluid. In addition, the effects of fill ratio, inclination angle and heat inputs on the heat transfer performance of a GHP are studied. Furthermore, the effect of heat flux on dimensional numbers, such as the Webber, Bond, Kutateladze and condensation numbers, are studied. The inclination angle, heat input and fill ratio of GHPs are varied in the range of 0°-90°, 25-250 W and 10-70 % respectively. It is found that the above parameters have a significant effect on the performance of a GHP. Due to the anodisation, the maximum enhancement in heat transfer coefficient at the evaporator is 39 % for a 90° inclination at a heat flux of 11 kW/m2. The reported performance enhancement of a GHP may be due to the large numbers of nucleation sites created by the anodisation process and enhancement in the capillary force due to the coating.

Sol–gel method as a way of carbonyl iron powder surface modification for interaction improvement

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

Małecki, P., E-mail: pawel.malecki@pwr.edu.pl; Kolman, K.; Pigłowski, J.

2015-03-15

This article presents a method for modification of carbonyl iron particles’ surface (CIP), (d{sub 50}=4–9 µm) by silica coatings obtained using the sol–gel method. Reaction parameters were determined to obtain dry magnetic powder with homogeneous silica coatings without further processing and without any by-product in the solid or liquid phase. This approach is new among the commonly used methods of silica coating of iron particles. No attempt has been made to cover a carbonyl iron surface by silica in a waste-free method, up to date. In the current work two different silica core/shell structures were made by the sol–gel process,more » based on different silica precursors: tetraethoxy-silane (TEOS) and tetramethoxy-silane (TMOS). The dependence between the synthesis procedure and thickness of silica shell covering carbonyl iron particles has been described. Surface morphology of the modified magnetic particles and the coating thickness were characterized with the use of scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Determination of the physicochemical structure of the obtained materials was performed by the energy-dispersive X-ray spectroscope (EDS), and the infrared technique (IR). The surface composition was analyzed using X-ray photoelectron spectroscopy (XPS). Additionally, distribution of particle size was measured using light microscopy. The new, efficient process of covering micro-size CIP with a nanometric silica layer was shown. Results of a performed analysis confirm the effectiveness of the presented method. - Highlights: • Proper covering CIP by sol–gel silica layer avoids agglomeration. • A new solid waste-free method of CIP coating is proposed. • Examination of the properties of modified CIP in depends on washing process. • Coatings on CIP particles doesn’t change the magnetic properties of particles.« less

Mapping surface tension induced menisci with application to tensiometry and refractometry.

PubMed

Mishra, Avanish; Kulkarni, Varun; Khor, Jian-Wei; Wereley, Steve

2015-07-28

In this work, we discuss an optical method for measuring surface tension induced menisci. The principle of measurement is based upon the change in the background pattern produced by the curvature of the meniscus acting as a lens. We measure the meniscus profile over an inclined glass plate and utilize the measured meniscus for estimation of surface tension and refractive index.

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

PubMed

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

2018-06-06

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

.beta.-silicon carbide protective coating and method for fabricating same

DOEpatents

Carey, Paul G.; Thompson, Jesse B.

1994-01-01

A polycrystalline beta-silicon carbide film or coating and method for forming same on components, such as the top of solar cells, to act as an extremely hard protective surface, and as an anti-reflective coating. This is achieved by DC magnetron co-sputtering of amorphous silicon and carbon to form a SiC thin film onto a surface, such as a solar cell. The thin film is then irradiated by a pulsed energy source, such as an excimer laser, to synthesize the poly- or .mu.c-SiC film on the surface and produce .beta.--SiC. While the method of this invention has primary application in solar cell manufacturing, it has application wherever there is a requirement for an extremely hard surface.

Spray shadowing for stress relief and mechanical locking in thick protective coatings

DOEpatents

Hollis, Kendall [Los Alamos, NM; Bartram, Brian [Los Alamos, NM

2007-05-22

A method for applying a protective coating on an article, comprising the following steps: selecting an article with a surface for applying a coating thickness; creating undercut grooves on the article, where the grooves depend beneath the surface to a bottom portion with the grooves having an upper width on the surface and a lower width on the bottom portion connected by side walls, where at least one of the side walls connects the upper width and the lower width to form an undercut angle with the surface less than 90.degree.; and, applying the protective coating onto the article to fill the undercut grooves and cover the surface, thereby forming weak paths within the protective coating.

Antimicrobial peptide coatings for hydroxyapatite: electrostatic and covalent attachment of antimicrobial peptides to surfaces

PubMed Central

Townsend, Leigh; Williams, Richard L.; Anuforom, Olachi; Berwick, Matthew R.; Halstead, Fenella; Hughes, Erik; Stamboulis, Artemis; Oppenheim, Beryl; Gough, Julie; Grover, Liam; Scott, Robert A. H.; Webber, Mark; Peacock, Anna F. A.; Belli, Antonio; Logan, Ann

2017-01-01

The interface between implanted devices and their host tissue is complex and is often optimized for maximal integration and cell adhesion. However, this also gives a surface suitable for bacterial colonization. We have developed a novel method of modifying the surface at the material–tissue interface with an antimicrobial peptide (AMP) coating to allow cell attachment while inhibiting bacterial colonization. The technology reported here is a dual AMP coating. The dual coating consists of AMPs covalently bonded to the hydroxyapatite surface, followed by deposition of electrostatically bound AMPs. The dual approach gives an efficacious coating which is stable for over 12 months and can prevent colonization of the surface by both Gram-positive and Gram-negative bacteria. PMID:28077764

Rapidly-Deposited Polydopamine Coating via High Temperature and Vigorous Stirring: Formation, Characterization and Biofunctional Evaluation

PubMed Central

Zhou, Ping; Deng, Yi; Lyu, Beier; Zhang, Ranran; Zhang, Hai; Ma, Hongwei; Lyu, Yalin; Wei, Shicheng

2014-01-01

Polydopamine (PDA) coating provides a promising approach for immobilization of biomolecules onto almost all kinds of solid substrates. However, the deposition kinetics of PDA coating as a function of temperature and reaction method is not well elucidated. Since dopamine self-polymerization usually takes a long time, therefore, rapid-formation of PDA film becomes imperative for surface modification of biomaterials and medical devices. In the present study, a practical method for preparation of rapidly-deposited PDA coating was developed using a uniquely designed device, and the kinetics of dopamine self-polymerization was investigated by QCM sensor system. It was found that high temperature and vigorous stirring could dramatically speed up the formation of PDA film on QCM chip surface. Surface characterization, BSA binding study, cell viability assay and antibacterial test demonstrates that the polydopamine coating after polymerization for 30 min by our approach exhibits similar properties to those of 24 h counterpart. The method has a great potential for rapid-deposition of polydopamine films to modify biomaterial surfaces. PMID:25415328

Influence of viscoelastic property on laser-generated surface acoustic waves in coating-substrate systems

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

Sun Hongxiang; Faculty of Science, Jiangsu University, Zhenjiang 212013; Zhang Shuyi

2011-04-01

Taking account of the viscoelasticity of materials, the pulsed laser generation of surface acoustic waves in coating-substrate systems has been investigated quantitatively by using the finite element method. The displacement spectra of the surface acoustic waves have been calculated in frequency domain for different coating-substrate systems, in which the viscoelastic properties of the coatings and substrates are considered separately. Meanwhile, the temporal displacement waveforms have been obtained by applying inverse fast Fourier transforms. The numerical results of the normal surface displacements are presented for different configurations: a single plate, a slow coating on a fast substrate, and a fast coatingmore » on a slow substrate. The influences of the viscoelastic properties of the coating and the substrate on the attenuation of the surface acoustic waves have been studied. In addition, the influence of the coating thickness on the attenuation of the surface acoustic waves has been also investigated in detail.« less

Method for Qualification of Coatings Applied to Wet Surfaces

DOT National Transportation Integrated Search

2009-12-16

The field application of a pipeline repair or rehabilitation coating usually cannot wait until ambient conditions become optimal. In a humid environment, water can condense on the pipe surface because the pipe surface is usually cooler than the ambie...

Method of making a coating of a microtextured surface

DOEpatents

Affinito, John D [Tucson, AZ; Graff, Gordon L [West Richland, WA; Martin, Peter M [Kennewick, WA; Gross, Mark E [Pasco, WA; Burrows, Paul E [Kennewick, WA; Sapochak, Linda S [Henderson, NV

2004-11-02

A method for conformally coating a microtextured surface. The method includes flash evaporating a polymer precursor forming an evaporate, passing the evaporate to a glow discharge electrode creating a glow discharge polymer precursor plasma from the evaporate, cryocondensing the glow discharge polymer precursor plasma on the microtextured surface and crosslinking the glow discharge polymer precursor plasma thereon, wherein the crosslinking resulting from radicals created in the glow discharge polymer precursor plasma.

Design and Performance of Property Gradient Ternary Nitride Coating Based on Process Control.

PubMed

Yan, Pei; Chen, Kaijie; Wang, Yubin; Zhou, Han; Peng, Zeyu; Jiao, Li; Wang, Xibin

2018-05-09

Surface coating is an effective approach to improve cutting tool performance, and multiple or gradient coating structures have become a common development strategy. However, composition mutations at the interfaces decrease the performance of multi-layered coatings. The key mitigation technique has been to reduce the interface effect at the boundaries. This study proposes a structure design method for property-component gradient coatings based on process control. The method produces coatings with high internal cohesion and high external hardness, which could reduce the composition and performance mutations at the interface. A ZrTiN property gradient ternary nitride coating was deposited on cemented carbide by multi-arc ion plating with separated Ti and Zr targets. The mechanical properties, friction behaviors, and cutting performances were systematically investigated, compared with a single-layer coating. The results indicated that the gradient coating had better friction and wear performance with lower wear rate and higher resistance to peeling off during sliding friction. The gradient coating had better wear and damage resistance in cutting processes, with lower machined surface roughness Ra. Gradient-structured coatings could effectively inhibit micro crack initiation and growth under alternating force and temperature load. This method could be extended to similar ternary nitride coatings.

Conformal coating of highly structured surfaces

DOEpatents

Ginley, David S.; Perkins, John; Berry, Joseph; Gennett, Thomas

2012-12-11

Method of applying a conformal coating to a highly structured substrate and devices made by the disclosed methods are disclosed. An example method includes the deposition of a substantially contiguous layer of a material upon a highly structured surface within a deposition process chamber. The highly structured surface may be associated with a substrate or another layer deposited on a substrate. The method includes depositing a material having an amorphous structure on the highly structured surface at a deposition pressure of equal to or less than about 3 mTorr. The method may also include removing a portion of the amorphous material deposited on selected surfaces and depositing additional amorphous material on the highly structured surface.

Blanch Resistant and Thermal Barrier NiAl Coating Systems for Advanced Copper Alloys

NASA Technical Reports Server (NTRS)

Raj, Sai V. (Inventor)

2005-01-01

A method of forming an environmental resistant thermal barrier coating on a copper alloy is disclosed. The steps include cleansing a surface of a copper alloy, depositing a bond coat on the cleansed surface of the copper alloy, depositing a NiAl top coat on the bond coat and consolidating the bond coat and the NiAl top coat to form the thermal barrier coating. The bond coat may be a nickel layer or a layer composed of at least one of copper and chromium-copper alloy and either the bond coat or the NiAl top coat or both may be deposited using a low pressure or vacuum plasma spray.

Development of antimicrobial coating by later-by-layer dip coating of chlorhexidine-loaded micelles.

PubMed

Tambunlertchai, Supreeda; Srisang, Siriwan; Nasongkla, Norased

2017-06-01

Layer-by-layer (LbL) dip coating, accompanying with the use of micelle structure, allows hydrophobic molecules to be coated on medical devices' surface via hydrogen bonding interaction. In addition, micelle structure also allows control release of encapsulated compound. In this research, we investigated methods to coat and maximize the amount of chlorhexidine (CHX) on silicone surface through LbL dip coating method utilizing hydrogen bonding interaction between PEG on micelle corona and PAA. The number of coated cycles was varied in the process and 90 coating cycles provided the maximum amount of CHX loaded onto the surface. In addition, pre-coating the surface with PAA enhanced the amount of coated CHX by 20%. Scanning electron microscope (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) were used to validate and characterize the coating. For control release aspect, the coated film tended to disrupt at physiological condition; hence chemical crosslinking was performed to minimize the disruption and maximize the release time. Chemical crosslinking at pH 2.5 and 4.5 were performed in the process. It was found that chemical crosslinking could help extend the release period up to 18 days. This was significantly longer when compared to the non-crosslinking silicone tube that could only prolong the release for 5 days. In addition, chemical crosslinking at pH 2.5 gave higher and better initial burst release, release period and antimicrobial properties than that of pH 4.5 or the normal used pH for chemical crosslinking process.

Drop impact on inclined superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Choi, Wonjae; Leclear, Sani; Leclear, Johnathon; Abhijeet, .; Park, Kyoo-Chul

We report an empirical study and dimensional analysis on the impact patterns of water drops on inclined superhydrophobic surfaces. While the classic Weber number determines the spreading and recoiling dynamics of a water drop on a horizontal / smooth surface, for a superhydrophobic surface, the dynamics depends on two distinct Weber numbers, each calculated using the length scale of the drop or of the pores on the surface. Impact on an inclined superhydrophobic surface is even more complicated, as the velocity that determines the Weber number is not necessarily the absolute speed of the drop but the velocity components normal and tangential to the surface. We define six different Weber numbers, using three different velocities (absolute, normal and tangential velocities) and two different length scales (size of the drop and of the texture). We investigate the impact patterns on inclined superhydrophobic surfaces with three different types of surface texture: (i) posts, (ii) ridges aligned with and (iii) ridges perpendicular to the impact direction. Results suggest that all six Weber numbers matter, but affect different parts of the impact dynamics, ranging from the Cassie-Wenzel transition, maximum spreading, to anisotropic deformation. We acknowledge financial support from the Office of Naval Research (ONR) through Contract 3002453812.

Runoff initiation from falling raindrops - comparison of smooth impervious surface and asphalt pavements. Effects of surface inclination and texture.

NASA Astrophysics Data System (ADS)

Nezlobin, David; Pariente, Sarah; Lavee, Hanoch; Sachs, Eyal; Levenberg, Eyal

2017-04-01

The processes of runoff initiation on smooth impervious surfaces and various asphalt pavements are investigated in laboratory rain simulator experiments and outdoor sprinkling tests. Visual and FLIR observations indicate that runoff initiation is associated with coalescence of drop clusters on the surface and complex changes in micro-connectivity. Depending on surface inclination, several morphological regimes of flow initiation have been observed. In the case of very small inclination the runoff initiation is governed by critical merging of drop clusters on the surface and develops in broad flows (very abrupt, but delayed). For larger inclinations, the runoff occurs in rivulets or strongly directed flow threads. On asphalt pavements the runoff initiation is also strongly affected by pavement SVF (Surface Void Fraction), texture and even by the asphalt hydrophobicity. A simplified bi-level model of the pavement surface may explain principal differences in the runoff initiation on asphalts with small, intermediate and large SVF values. For small SVF (standard fresh asphalts) the runoff develops on the upper surface level, and filling of the surface voids is not always required (especially for the large inclinations). For intermediate SVF (considerably deteriorated asphalts) the runoff develops as well on the upper surface level, but only after considerable filling of the surface voids. Finally, on severely deteriorated asphalts (very large SVFs) the runoff develops on the "bottom" level of asphalt surface, after only partial filling of the surface voids. Other factors, such as drops splash and splitting, also affect the process of runoff initiation and explain rather considerable differences (sometimes of 2-3 mm rain depth) in the runoff thresholds on various non-porous asphalt pavements. Similar phenomena can be probably observed on certain types of rock outcrops.

Comparative evaluation of the three different surface treatments - conventional, laser and Nano technology methods in enhancing the surface characteristics of commercially pure titanium discs and their effects on cell adhesion: An in vitro study.

PubMed

Vignesh; Nayar, Sanjna; Bhuminathan; Mahadevan; Santhosh, S

2015-04-01

The surface area of the titanium dental implant materials can be increased by surface treatments without altering their shape and form, thereby increasing the biologic properties of the biomaterial. A good biomaterial helps in early cell adhesion and cell signaling. In this study, the commercially pure titanium surfaces were prepared to enable machined surfaces to form a control material and to be compared with sandblasted and acid-etched surfaces, laser treated surfaces and titanium dioxide (20 nm) Nano-particle coated surfaces. The surface elements were characterized. The biocompatibility was evaluated by cell culture in vitro using L929 fibroblasts. The results suggested that the titanium dioxide Nano-particle coated surfaces had good osteoconductivity and can be used as a potential method for coating the biomaterial.

Comparison of self-cleaning properties of three titania coatings on float glass

NASA Astrophysics Data System (ADS)

Piispanen, Minna; Hupa, Leena

2011-11-01

This work compares the self-cleaning properties of experimental TiO2 and TiO2-Ag coatings on float glass with a commercial self-cleaning glass. In the experimental surfaces, TiO2 coating was applied to float glass via the sol-gel route, while TiO2-Ag coating was applied by the liquid flame spray method, which deposits TiO2-Ag composite nanoparticles on the surface. The effect of the coatings on the surface wettability and the activation time for achieving hydrophilicity was studied through water contact angle as a function of exposure time to UV light. The surface morphology was investigated by using scanning electron microscopy (SEM) and confocal optical microscopy. The photocatalytic activity of the coatings was examined with methylene blue and stearic acid degradation tests. Finally, the soil attachment to the surfaces was tested with a sebum-based model soil. The sol-gel TiO2 coating became superhydrophilic within a few hours, while the activation time needed for the commercial titania coated glass was several days. The surface with the TiO2-Ag nanoparticles did not show any marked changes in the water contact angle. The commercial titania coated and the sol-gel TiO2 surfaces showed self-cleaning properties and clearly lower attachment of soil than the uncoated and TiO2-Ag coated surfaces. The difference in the interaction of the surfaces with the organic contaminants was assumed to depend mainly on differences in the thickness of the coatings.

Composite neutron absorbing coatings for nuclear criticality control

DOEpatents

Wright, Richard N.; Swank, W. David; Mizia, Ronald E.

2005-07-19

Thermal neutron absorbing composite coating materials and methods of applying such coating materials to spent nuclear fuel storage systems are provided. A composite neutron absorbing coating applied to a substrate surface includes a neutron absorbing layer overlying at least a portion of the substrate surface, and a corrosion resistant top coat layer overlying at least a portion of the neutron absorbing layer. An optional bond coat layer can be formed on the substrate surface prior to forming the neutron absorbing layer. The neutron absorbing layer can include a neutron absorbing material, such as gadolinium oxide or gadolinium phosphate, dispersed in a metal alloy matrix. The coating layers may be formed by a plasma spray process or a high velocity oxygen fuel process.

Incorporation of silver nanoparticles on the surface of orthodontic microimplants to achieve antimicrobial properties

PubMed Central

Venugopal, Adith; Muthuchamy, Nallal; Tejani, Harsh; Gopalan, Anantha-Iyengar; Lee, Kwang-Pill; Lee, Heon-Jin

2017-01-01

Objective Microbial aggregation around dental implants can lead to loss/loosening of the implants. This study was aimed at surface treating titanium microimplants with silver nanoparticles (AgNPs) to achieve antibacterial properties. Methods AgNP-modified titanium microimplants (Ti-nAg) were prepared using two methods. The first method involved coating the microimplants with regular AgNPs (Ti-AgNP) and the second involved coating them with a AgNP-coated biopolymer (Ti-BP-AgNP). The topologies, microstructures, and chemical compositions of the surfaces of the Ti-nAg were characterized by scanning electron microscopy (SEM) equipped with energy-dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). Disk diffusion tests using Streptococcus mutans, Streptococcus sanguinis, and Aggregatibacter actinomycetemcomitans were performed to test the antibacterial activity of the Ti-nAg microimplants. Results SEM revealed that only a meager amount of AgNPs was sparsely deposited on the Ti-AgNP surface with the first method, while a layer of AgNP-coated biopolymer extended along the Ti-BP-AgNP surface in the second method. The diameters of the coated nanoparticles were in the range of 10 to 30 nm. EDS revealed 1.05 atomic % of Ag on the surface of the Ti-AgNP and an astounding 21.2 atomic % on the surface of the Ti-BP-AgNP. XPS confirmed the metallic state of silver on the Ti-BP-AgNP surface. After 24 hours of incubation, clear zones of inhibition were seen around the Ti-BP-AgNP microimplants in all three test bacterial culture plates, whereas no antibacterial effect was observed with the Ti-AgNP microimplants. Conclusions Titanium microimplants modified with Ti-BP-AgNP exhibit excellent antibacterial properties, making them a promising implantable biomaterial. PMID:28127534

Assessment of Reinforced Concrete Surface Breaking Crack Using Rayleigh Wave Measurement.

PubMed

Lee, Foo Wei; Chai, Hwa Kian; Lim, Kok Sing

2016-03-05

An improved single sided Rayleigh wave (R-wave) measurement was suggested to characterize surface breaking crack in steel reinforced concrete structures. Numerical simulations were performed to clarify the behavior of R-waves interacting with surface breaking crack with different depths and degrees of inclinations. Through analysis of simulation results, correlations between R-wave parameters of interest and crack characteristics (depth and degree of inclination) were obtained, which were then validated by experimental measurement of concrete specimens instigated with vertical and inclined artificial cracks of different depths. Wave parameters including velocity and amplitude attenuation for each case were studied. The correlations allowed us to estimate the depth and inclination of cracks measured experimentally with acceptable discrepancies, particularly for cracks which are relatively shallow and when the crack depth is smaller than the wavelength.

Influence of pretreatment on the surface characteristics of PLLA fibers and subsequent hydroxyapatite coating.

PubMed

Peng, F; Olson, J R; Shaw, M T; Wei, M

2009-01-01

A fibrous precursor for bone repair composites was made by coating poly(L-lactide) (PLLA) fibers with hydroxyapatite (HA) using a biomimetic method. To enhance the bonding between the HA coating and the PLLA fiber, PLLA fibers were etched with either sodium hydroxide or sodium hypochlorite to generate carboxyl groups on fiber surfaces. The experiments were designed to determine the influence of etching on the fiber surface morphology and chemistry as well as the subsequent HA coating on the etched fiber surfaces. It was found that the etching pretreatment increased the roughness as well as the hydrophilicity of fibers, indicating that hydrolysis of PLLA chains had taken place on fiber surfaces. The etching pretreatment also promoted HA coating formation by introducing thicker coating on the surface of fibers with a longer etching time, a higher etching concentration, or with NaOCl as the etching agent. A mechanism of surface hydrolysis and oxidation of PLLA was proposed. (c) 2008 Wiley Periodicals, Inc.

Effects of sandblasting and silica-coating procedures on pure titanium.

PubMed

Kern, M; Thompson, V P

1994-10-01

Silica coating titanium improves chemomechanical bonding. Sandblasting is recommended as a pretreatment to thermal silica coating (Silicoater MD) or as part of a tribochemical silica coating process (Rocatec). This study evaluated the effects of sandblasting and coating techniques on volume loss, surface morphology and composition changes in pure titanium. Volume loss of titanium was similar to values reported for base alloys and does not seem to be critical for the clinical fit of restorations. Embedded alumina particles were found in the titanium after sandblasting and the alumina content increased to a range of 27.5-39.3 wt% as measured by EDS. Following tribochemical silica coating, a layer of small silica particles remained on the surface, increasing the silica content to a range of 17.9-19.5 wt%. Ultrasonic cleaning removed loose alumina or silica particles from the surface, resulting in only slight decreases in alumina or silica contents, suggesting firm attachment of most of the alumina and silica to the titanium surface. Silica content following thermal silica coating treatment increased only slightly from the sandblasted specimen to 1.4 wt%. The silica layer employed by these silica coating methods differs widely in both morphology and thickness. These results provide a basis for explanation of adhesive failure modes in bond strength tests and for developing methods to optimize resin bonding. Clinically, ultrasonic cleaning of sandblasted and tribochemically silica coated titanium should improve resin bonding as loose surface particles are removed without relevant changes in composition.

Muscular activity of lower limb muscles associated with working on inclined surfaces

PubMed Central

Lu, Ming-Lun; Kincl, Laurel; Lowe, Brian; Succop, Paul; Bhattacharya, Amit

2015-01-01

This study investigated effects of visual cues, muscular fatigue, task performance and experience of working on inclined surfaces on activity of postural muscles in the lower limbs associated with maintaining balance on three inclined surfaces—0°, 14° and 26°. Normalized electromyographic (NEMG) data were collected on 44 professional roofers bilaterally from the rectus femoris, biceps femoris, tibialii anterior, and gastrocnemii medial muscle groups. The 50th and 95th percentile normalized EMG amplitudes were used as EMG variables. Results showed that inclination angle and task performance caused a significant increase in the NEMG amplitudes of all postural muscles. Visual cues were significantly associated with a decrease in the 95th percentile EMG amplitude for the right gastrocnemius medial and tibialis anterior. Fatigue was related to a significant decrease in the NEMG amplitude for the rectus femoris. Experience of working on inclined surfaces did not have a significant effect on the NEMG amplitude. PMID:25331562

Method of coating the interior surface of hollow objects with a diffusion coating

DOEpatents

Knowles, Shawn D.; Senor, David J.; Forbes, Steven V.; Johnson, Roger N.; Hollenberg, Glenn W.

2005-03-15

A method for forming a diffusion coating on the interior of surface of a hollow object wherein a filament, extending through a hollow object and adjacent to the interior surface of the object, is provided, with a coating material, in a vacuum. An electrical current is then applied to the filament to resistively heat the filament to a temperature sufficient to transfer the coating material from the filament to the interior surface of the object. The filament is electrically isolated from the object while the filament is being resistively heated. Preferably, the filament is provided as a tungsten filament or molybdenum filament. Preferably, the coating materials are selected from the group consisting of Ag, Al, As, Au, Ba, Be, Bi, Ca, Cd, Co, Cr, Cu, Dy, Er, Eu, Fe, Ga, Ge, Hg, In, K, Li, Mg, Mn, Na, Ni P, Pb, Pd, Pr, S, Sb, Sc, Se, Si, Sn, Sr, Te, Tl, Y, Yb, Zn, and combinations thereof. The invention additionally allows for the formation of nitrides, hydrides, or carbides of all the possible coating materials, where such compounds exist, by providing a partial pressure of nitrogen, hydrogen, hydrocarbons, or combination thereof, within the vacuum.

Non-destructive evaluation of coating thickness using guided waves

NASA Astrophysics Data System (ADS)

Ostiguy, Pierre-Claude; Quaegebeur, Nicolas; Masson, Patrice

2015-04-01

Among existing strategies for non-destructive evaluation of coating thickness, ultrasonic methods based on the measurement of the Time-of-Flight (ToF) of high frequency bulk waves propagating through the thickness of a structure are widespread. However, these methods only provide a very localized measurement of the coating thickness and the precision on the results is largely affected by the surface roughness, porosity or multi-layered nature of the host structure. Moreover, since the measurement is very local, inspection of large surfaces can be time consuming. This article presents a robust methodology for coating thickness estimation based on the generation and measurement of guided waves. Guided waves have the advantage over ultrasonic bulk waves of being less sensitive to surface roughness, and of measuring an average thickness over a wider area, thus reducing the time required to inspect large surfaces. The approach is based on an analytical multi-layer model and intercorrelation of reference and measured signals. The method is first assessed numerically for an aluminum plate, where it is demonstrated that coating thickness can be measured within a precision of 5 micrometers using the S0 mode at frequencies below 500 kHz. Then, an experimental validation is conducted and results show that coating thicknesses in the range of 10 to 200 micrometers can be estimated within a precision of 10 micrometers of the exact coating thickness on this type of structure.

Infrared spectroscopic investigations on the distribution of residual grease on textiles

NASA Astrophysics Data System (ADS)

Siedler, J.; Schumacher-Hamedat, Ursula; Hoecker, Hartwig

1992-03-01

Surface modification of textile materials is of major importance in the modern textile industry. Several methods are commonly applied to produce a broad range of coated materials. The adhesion between the coating polymers and the textile fibers often determines the quality. Improved adhesion of the coating is achieved by a chemical bonding (covalent or ionic) between the coating materials and the textile. The efficiency,however, is dependent on the orientation of the functional groups of the outmost molecular layers of the fibers. Therefore, we have used surface sensitive methods to analyze the surface structure of proteinaceous fibers. Homopoly(aminoacid) films like poly(-(gamma) -benzyl-L-glutamate) and poly(- (Beta) -benzyl-L-aspartate) have been chosen as models for natural fibers like wool.

Preparation of low-sulfur platinum and platinum aluminide layers in thermal barrier coatings

NASA Technical Reports Server (NTRS)

Spitsberg, Irene T. (Inventor); Walston, William S. (Inventor); Schaeffer, Jon C. (Inventor)

2003-01-01

A method for preparing a coated nickel-base superalloy article reduces the sulfur content of the surface region of the metallic coating layers to low levels, thereby improving the adhesion of the coating layers to the article. The method includes depositing a first layer of platinum overlying the surface of a substrate, depositing a second layer of aluminum over the platinum, and final desulfurizing the article by heating the article to elevated temperature, preferably in hydrogen, and removing a small amount of material from the surface that was exposed during the step of heating. A ceramic layer may be deposited over the desulfurized article. The article may also be similarly desulfurized at other points in the fabrication procedure.

METHOD FOR COATING GRAPHITE WITH METALLIC CARBIDES

DOEpatents

Steinberg, M.A.

1960-03-22

A method for producing refractory coatings of metallic carbides on graphite was developed. In particular, the graphite piece to be coated is immersed in a molten solution of 4 to 5% by weight of zirconium, titanium, or niobium dissolved in tin. The solution is heated in an argon atmosphere to above 1400 deg C, whereby the refractory metal reacts with the surface of the graphite to form a layer of metalic carbide. The molten solution is cooled to 300 to 400 deg C, and the graphite piece is removed. Excess tin is wiped from the graphite, which is then heated in vacuum to above 2300 deg C. The tin vaporizes from the graphite surface, leaving the surface coated with a tenacious layer of refractory metallic carbide.

Radiative Effects on a Free Convective MHD Flow past a Vertically Inclined Plate with with Heat Source and Sink

NASA Astrophysics Data System (ADS)

Sambath, P.; Pullepu, Bapuji; Kannan, R. M.

2018-04-01

The impact of thermal radiation on unsteady laminar free convective MHD flow of a incompressible viscous fluid passes through a vertically inclined plate under the persuade of heat source and sink is presented here.Plate surface is considered to have variable wall temperature. The fluid regarded as gray absorbing / emitting, but non dispersing medium. The periphery layer dimensionless equations that administer the flow are evaluated by a finite difference implicit method called Crank Nicolson method. Numerical solutions are carried out for velocity, temperature, local shear stress, heat transfer rate for various values of the parameters (Pr, λ, Δ M, Rd ) are presented.

Superhydrophobic-superhydrophilic binary micropatterns by localized thermal treatment of polyhedral oligomeric silsesquioxane (POSS)-silica films

NASA Astrophysics Data System (ADS)

Schutzius, Thomas M.; Bayer, Ilker S.; Jursich, Gregory M.; Das, Arindam; Megaridis, Constantine M.

2012-08-01

Surfaces patterned with alternating (binary) superhydrophobic-superhydrophilic regions can be found naturally, offering a bio-inspired template for efficient fluid collection and management technologies. We describe a simple wet-processing, thermal treatment method to produce such patterns, starting with inherently superhydrophobic polysilsesquioxane-silica composite coatings prepared by spray casting nanoparticle dispersions. Such coatings become superhydrophilic after localized thermal treatment by means of laser irradiation or open-air flame exposure. When laser processed, the films are patternable down to ~100 μm scales. The dispersions consist of hydrophobic fumed silica (HFS) and methylsilsesquioxane resin, which are dispersed in isopropanol and deposited onto various substrates (glass, quartz, aluminum, copper, and stainless steel). The coatings are characterized by advancing, receding, and sessile contact angle measurements before and after thermal treatment to delineate the effects of HFS filler concentration and thermal treatment on coating wettability. SEM, XPS and TGA measurements reveal the effects of thermal treatment on surface chemistry and texture. The thermally induced wettability shift from superhydrophobic to superhydrophilic is interpreted with the Cassie-Baxter wetting theory. Several micropatterned wettability surfaces demonstrate potential in pool boiling heat transfer enhancement, capillarity-driven liquid transport in open surface-tension-confined channels (e.g., lab-on-a-chip), and select surface coating applications relying on wettability gradients. Advantages of the present approach include the inherent stability and inertness of the organosilane-based coatings, which can be applied on many types of surfaces (glass, metals, etc.) with ease. The present method is also scalable to large areas, thus being attractive for industrial coating applications.Surfaces patterned with alternating (binary) superhydrophobic-superhydrophilic regions can be found naturally, offering a bio-inspired template for efficient fluid collection and management technologies. We describe a simple wet-processing, thermal treatment method to produce such patterns, starting with inherently superhydrophobic polysilsesquioxane-silica composite coatings prepared by spray casting nanoparticle dispersions. Such coatings become superhydrophilic after localized thermal treatment by means of laser irradiation or open-air flame exposure. When laser processed, the films are patternable down to ~100 μm scales. The dispersions consist of hydrophobic fumed silica (HFS) and methylsilsesquioxane resin, which are dispersed in isopropanol and deposited onto various substrates (glass, quartz, aluminum, copper, and stainless steel). The coatings are characterized by advancing, receding, and sessile contact angle measurements before and after thermal treatment to delineate the effects of HFS filler concentration and thermal treatment on coating wettability. SEM, XPS and TGA measurements reveal the effects of thermal treatment on surface chemistry and texture. The thermally induced wettability shift from superhydrophobic to superhydrophilic is interpreted with the Cassie-Baxter wetting theory. Several micropatterned wettability surfaces demonstrate potential in pool boiling heat transfer enhancement, capillarity-driven liquid transport in open surface-tension-confined channels (e.g., lab-on-a-chip), and select surface coating applications relying on wettability gradients. Advantages of the present approach include the inherent stability and inertness of the organosilane-based coatings, which can be applied on many types of surfaces (glass, metals, etc.) with ease. The present method is also scalable to large areas, thus being attractive for industrial coating applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c2nr30979c

The Effect of Leading-Edge Sweep and Surface Inclination on the Hypersonic Flow Field Over a Blunt Flat Plate

NASA Technical Reports Server (NTRS)

Creager, Marcus O.

1959-01-01

An investigation of the effects of variation of leading-edge sweep and surface inclination on the flow over blunt flat plates was conducted at Mach numbers of 4 and 5.7 at free-stream Reynolds numbers per inch of 6,600 and 20,000, respectively. Surface pressures were measured on a flat plate blunted by a semicylindrical leading edge over a range of sweep angles from 0 deg to 60 deg and a range of surface inclinations from -10 deg to +10 deg. The surface pressures were predicted within an average error of +/- 8 percent by a combination of blast-wave and boundary-layer theory extended herein to include effects of sweep and surface inclination. This combination applied equally well to similar data of other investigations. The local Reynolds number per inch was found to be lower than the free-stream Reynolds number per inch. The reduction in local Reynolds number was mitigated by increasing the sweep of the leading edge. Boundary-layer thickness and shock-wave shape were changed little by the sweep of the leading edge.

Antimicrobial peptide coatings for hydroxyapatite: electrostatic and covalent attachment of antimicrobial peptides to surfaces.

PubMed

Townsend, Leigh; Williams, Richard L; Anuforom, Olachi; Berwick, Matthew R; Halstead, Fenella; Hughes, Erik; Stamboulis, Artemis; Oppenheim, Beryl; Gough, Julie; Grover, Liam; Scott, Robert A H; Webber, Mark; Peacock, Anna F A; Belli, Antonio; Logan, Ann; de Cogan, Felicity

2017-01-01

The interface between implanted devices and their host tissue is complex and is often optimized for maximal integration and cell adhesion. However, this also gives a surface suitable for bacterial colonization. We have developed a novel method of modifying the surface at the material-tissue interface with an antimicrobial peptide (AMP) coating to allow cell attachment while inhibiting bacterial colonization. The technology reported here is a dual AMP coating. The dual coating consists of AMPs covalently bonded to the hydroxyapatite surface, followed by deposition of electrostatically bound AMPs. The dual approach gives an efficacious coating which is stable for over 12 months and can prevent colonization of the surface by both Gram-positive and Gram-negative bacteria. © 2017 The Author(s).

[beta]-silicon carbide protective coating and method for fabricating same

DOEpatents

Carey, P.G.; Thompson, J.B.

1994-11-01

A polycrystalline beta-silicon carbide film or coating and method for forming same on components, such as the top of solar cells, to act as an extremely hard protective surface, and as an anti-reflective coating are disclosed. This is achieved by DC magnetron co-sputtering of amorphous silicon and carbon to form a SiC thin film onto a surface, such as a solar cell. The thin film is then irradiated by a pulsed energy source, such as an excimer laser, to synthesize the poly- or [mu]c-SiC film on the surface and produce [beta]-SiC. While the method of this invention has primary application in solar cell manufacturing, it has application wherever there is a requirement for an extremely hard surface. 3 figs.

Repair of a mirror coating on a large optic for high laser damage applications using ion milling and over-coating methods

NASA Astrophysics Data System (ADS)

Field, Ella S.; Bellum, John C.; Kletecka, Damon E.

2017-01-01

When an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched. Repairs were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO2 and SiO2 layers for high reflection at 1054 nm at 45 deg incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO2 to evaluate the ability of each repair method to restore the coating's high laser-induced damage threshold (LIDT) of 64.0 J/cm2. The repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 to 61.0 J/cm2.

Anticorrosion efficiency of ultrasonically deposited silica coatings on titanium

NASA Astrophysics Data System (ADS)

Ertaş, Fatma Sinem; Kaş, Recep; Mikó, Annamária; Birer, Özgür

2013-07-01

We utilized high intensity ultrasound to prepare coatings of silica and organically modified silica composed of multiple layers of densely packed nanoparticles. Ultrasound was used to collide nanoparticles onto an activated titanium surface with high speed. Large areas could be homogeneously coated by this method. These coatings were characterized by spectroscopy and microscopy methods and the anticorrosion efficiency in NaCl solution was evaluated by electrochemical measurements. The results indicated that the composite coatings provided good quality barrier layer on bare titanium and decreased the anodic corrosion rate. It was found that increase in the organic content of the coating shifted the passivation potential towards more positive direction. The comparison of the impedance results recorded at the corrosion potential pointed out that in each case a good quality barrier layer was formed on the titanium surface. The outstanding corrosion resistance of the composite coatings with only ~200 nm thickness shows that ultrasound assisted deposition can be a competitive method to obtain corrosion protective layers.

Porous coatings from wire mesh for bone implants

DOEpatents

Sump, Kenneth R.

1986-01-01

A method of coating areas of bone implant elements and the resulting implant having a porous coating are described. Preselected surface areas are covered by a preform made from continuous woven lengths of wire. The preform is compressed and heated to assure that diffusion bonding occurs between the wire surfaces and between the surface boundaries of the implant element and the wire surfaces in contact with it. Porosity is achieved by control of the resulting voids between the bonded wire portions.

POLLUTION PREVENTION METHODS IN THE SURFACE COATING INDUSTRY

EPA Science Inventory

The surface coating industry is rapidly changing to meet environmental and economic pressures. Some of the changes include new formulations which meet environmental regulations, higher performance finishes with improved properties, continued development of solventless technologie...

Film flow and heat transfer during condensation of steam on inclined and vertical nonround tubes

NASA Astrophysics Data System (ADS)

Nikitin, N. N.; Semenov, V. P.

2008-03-01

We describe a mathematical model for calculating heat transfer during film condensation of stagnant steam on inclined and vertical smooth tubes with cross sections of arbitrary shape that takes into account the action of surface tension forces. The heat-transfer coefficients are calculated, and the hydrodynamic pattern is presented in which a condensate film flows over the surface of nonround inclined and vertical tubes with cross-section of different shapes.

Method for applying photographic resists to otherwise incompatible substrates

NASA Technical Reports Server (NTRS)

Fuhr, W. (Inventor)

1981-01-01

A method for applying photographic resists to otherwise incompatible substrates, such as a baking enamel paint surface, is described wherein the uncured enamel paint surface is coated with a non-curing lacquer which is, in turn, coated with a partially cured lacquer. The non-curing lacquer adheres to the enamel and a photo resist material satisfactorily adheres to the partially cured lacquer. Once normal photo etching techniques are employed the lacquer coats can be easily removed from the enamel leaving the photo etched image. In the case of edge lighted instrument panels, a coat of uncured enamel is placed over the cured enamel followed by the lacquer coats and the photo resists which is exposed and developed. Once the etched uncured enamel is cured, the lacquer coats are removed leaving an etched panel.

Biocompatibility of a functionally graded bioceramic coating made by wide-band laser cladding.

PubMed

Weidong, Zhu; Qibin, Liu; Min, Zheng; Xudong, Wang

2008-11-01

The application of plasma spray is the most popular method by which a metal-bioceramic surface composite can be prepared for the repair of biological hard-tissue, but this method has disadvantages. These disadvantages include poor coating-to-substrate adhesion, low mechanical strength, and brittleness of the coating. In the investigation described in this article, a gradient bioceramic coating was prepared on a Ti-6Al-4V titanium alloy surface using a gradient composite design and wide-band laser cladding techniques. Using a trilayer-structure composed of a substratum, an alloy and bioceramics, the coating was chemically and metallurgically bonded with the substratum. The coating, which contains beta-tricalcium phosphate and hydroxyapatite, showed favorable biocompatibility with the bone tissue and promoted in vivo osteogenesis.

Influence of process parameters on the content of biomimetic calcium phosphate coating on titanium: a Taguchi analysis.

PubMed

Thammarakcharoen, Faungchat; Suvannapruk, Waraporn; Suwanprateeb, Jintamai

2014-10-01

In this study, a statistical design of experimental methodology based on Taguchi orthogonal design has been used to study the effect of various processing parameters on the amount of calcium phosphate coating produced by such technique. Seven control factors with three levels each including sodium hydroxide concentration, pretreatment temperature, pretreatment time, cleaning method, coating time, coating temperature and surface area to solution volume ratio were studied. X-ray diffraction revealed that all the coatings consisted of the mixture of octacalcium phosphate (OCP) and hydroxyapatite (HA) and the presence of each phase depended on the process conditions used. Various content and size (-1-100 μm) of isolated spheroid particles with nanosized plate-like morphology deposited on the titanium surface or a continuous layer of plate-like nanocrystals having the plate thickness in the range of -100-300 nm and the plate width in the range of 3-8 μm were formed depending on the process conditions employed. The optimum condition of using sodium hydroxide concentration of 1 M, pretreatment temperature of 70 degrees C, pretreatment time of 24 h, cleaning by ultrasonic, coating time of 6 h, coating temperature of 50 degrees C and surface area to solution volume ratio of 32.74 for producing the greatest amount of the coating formed on the titanium surface was predicted and validated. In addition, coating temperature was found to be the dominant factor with the greatest contribution to the coating formation while coating time and cleaning method were significant factors. Other factors had negligible effects on the coating performance.

Potential Fungus surface resistance of the silica/acrylic coated leaves waste composite

NASA Astrophysics Data System (ADS)

Masturi; Jannah, WN; Maulana, RM; Darsono, T.; Sunarno; Rustad, S.

2018-04-01

The composite coated by some materials coaters have been made. This coating was done to isolate the fungus possibly growing on the composite. The composite was made from a mixture of teak leaves waste and polyurethane polymer using a simple mixing method; then the mixture was pressed at a pressure of 3 metric-tons for 15 minutes. The composite produced then was coated with acrylic only and acrylic-silica using spray method. The coated samples then were characterized using scanning electron microscopy (SEM) to determine the surface pores. Further, it was obtained the average surface pore size of acrylic coater is 1.24 µm, while the acrylic-silica pore forms an oval shape with a length and a width of 0.75 µm and 0.38 µm, respectively. In comparison with the fungus size of 2-7 µm, it can be concluded that the composite is proper as home appliance application.

Method for applying a diffusion barrier interlayer for high temperature components

DOEpatents

Wei, Ronghua; Cheruvu, Narayana S.

2016-03-08

A coated substrate and a method of forming a diffusion barrier coating system between a substrate and a MCrAl coating, including a diffusion barrier coating deposited onto at least a portion of a substrate surface, wherein the diffusion barrier coating comprises a nitride, oxide or carbide of one or more transition metals and/or metalloids and a MCrAl coating, wherein M includes a transition metal or a metalloid, deposited on at least a portion of the diffusion barrier coating, wherein the diffusion barrier coating restricts the inward diffusion of aluminum of the MCrAl coating into the substrate.

Method of protecting the surface of a substrate. [by applying aluminide coating

NASA Technical Reports Server (NTRS)

Gedwill, M. A. (Inventor); Grisaffe, S. J.

1974-01-01

The surface of a metallic base system is initially coated with a metallic alloy layer that is ductile and oxidation resistant. An aluminide coating is then applied to the metallic alloy layer. The chemistry of the metallic alloy layer is such that the oxidation resistance of the subsequently aluminized outermost layer is not seriously degraded.

Non-metallic coating thickness prediction using artificial neural network and support vector machine with time resolved thermography

NASA Astrophysics Data System (ADS)

Wang, Hongjin; Hsieh, Sheng-Jen; Peng, Bo; Zhou, Xunfei

2016-07-01

A method without requirements on knowledge about thermal properties of coatings or those of substrates will be interested in the industrial application. Supervised machine learning regressions may provide possible solution to the problem. This paper compares the performances of two regression models (artificial neural networks (ANN) and support vector machines for regression (SVM)) with respect to coating thickness estimations made based on surface temperature increments collected via time resolved thermography. We describe SVM roles in coating thickness prediction. Non-dimensional analyses are conducted to illustrate the effects of coating thicknesses and various factors on surface temperature increments. It's theoretically possible to correlate coating thickness with surface increment. Based on the analyses, the laser power is selected in such a way: during the heating, the temperature increment is high enough to determine the coating thickness variance but low enough to avoid surface melting. Sixty-one pain-coated samples with coating thicknesses varying from 63.5 μm to 571 μm are used to train models. Hyper-parameters of the models are optimized by 10-folder cross validation. Another 28 sets of data are then collected to test the performance of the three methods. The study shows that SVM can provide reliable predictions of unknown data, due to its deterministic characteristics, and it works well when used for a small input data group. The SVM model generates more accurate coating thickness estimates than the ANN model.

Chemically grafted fibronectin for use in QCM-D cell studies

PubMed Central

Sobolewski, Peter; Tomczyk, Nancy; Composto, Russell J.; Eckmann, David M.

2014-01-01

Traditionally, fibronectin has been used as a physisorbed surface coating (physFN) in cell culture experiments due to its critical role in cell adhesion. However, because the resulting layer is thick, unstable, and of unpredictable uniformity, this method of fibronectin deposition is unsuitable for some types of research, including quartz crystal microbalance (QCM) experiments involving cells. Here, we present a new method for chemical immobilization of fibronectin onto silicon oxide surfaces, including QCM crystals pre-coated with silicon oxide. We characterize these chemically coated fibronectin surfaces (chemFN) as well as physFN ones using surface ellipsometry (SE), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), and contact angle measurements. A cell culture model demonstrates that cells on chemFN and physFN surfaces exhibit similar viability, structure, adhesion and metabolism. Finally, we perform QCM experiments using cells on both surfaces which demonstrate the superior suitability of chemFN coatings for QCM research, and provide real-time QCM-D data from cells subjected to an actin depolymerizing agent. Overall, our method of chemical immobilization of fibronectin yields great potential for furthering cellular experiments in which thin, stable and uniform coatings are desirable. As QCM research with cells has been rather limited in success thus far, we anticipate that this new technique will particularly benefit this experimental system by availing it to the much broader field of cell mechanics. PMID:24657645

Evaluation of different models to estimate the global solar radiation on inclined surface

NASA Astrophysics Data System (ADS)

Demain, C.; Journée, M.; Bertrand, C.

2012-04-01

Global and diffuse solar radiation intensities are, in general, measured on horizontal surfaces, whereas stationary solar conversion systems (both flat plate solar collector and solar photovoltaic) are mounted on inclined surface to maximize the amount of solar radiation incident on the collector surface. Consequently, the solar radiation incident measured on a tilted surface has to be determined by converting solar radiation from horizontal surface to tilted surface of interest. This study evaluates the performance of 14 models transposing 10 minutes, hourly and daily diffuse solar irradiation from horizontal to inclined surface. Solar radiation data from 8 months (April to November 2011) which include diverse atmospheric conditions and solar altitudes, measured on the roof of the radiation tower of the Royal Meteorological Institute of Belgium in Uccle (Longitude 4.35°, Latitude 50.79°) were used for validation purposes. The individual model performance is assessed by an inter-comparison between the calculated and measured solar global radiation on the south-oriented surface tilted at 50.79° using statistical methods. The relative performance of the different models under different sky conditions has been studied. Comparison of the statistical errors between the different radiation models in function of the clearness index shows that some models perform better under one type of sky condition. Putting together different models acting under different sky conditions can lead to a diminution of the statistical error between global measured solar radiation and global estimated solar radiation. As models described in this paper have been developed for hourly data inputs, statistical error indexes are minimum for hourly data and increase for 10 minutes and one day frequency data.

Repair of a Mirror Coating on a Large Optic for High Laser Damage Applications using Ion Milling and Over-Coating Methods.

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

Field, Ella Suzanne; Bellum, John Curtis; Kletecka, Damon E.

When an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface, and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched. Repairsmore » were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO 2 and SiO 2 layers for high reflection at 1054 nm at 45° incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO 2 to evaluate the ability of each repair method to restore the coating’s high laser-induced damage threshold (LIDT) of 64.0 J/cm 2. Finally, the repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 – 61.0 J/cm 2.« less

Repair of a mirror coating on a large optic for high laser damage applications using ion milling and over-coating methods

DOE PAGES

Field, Ella S.; Bellum, John C.; Kletecka, Damon E.

2016-07-08

Here, when an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched.more » Repairs were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO 2 and SiO 2 layers for high reflection at 1054 nm at 45 deg incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO2 to evaluate the ability of each repair method to restore the coating’s high laser-induced damage threshold (LIDT) of 64.0 J/cm 2. The repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 to 61.0 J/cm 2.« less

Repair of a Mirror Coating on a Large Optic for High Laser Damage Applications using Ion Milling and Over-Coating Methods.

DOE PAGES

Field, Ella Suzanne; Bellum, John Curtis; Kletecka, Damon E.

2016-06-01

When an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface, and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched. Repairsmore » were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO 2 and SiO 2 layers for high reflection at 1054 nm at 45° incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO 2 to evaluate the ability of each repair method to restore the coating’s high laser-induced damage threshold (LIDT) of 64.0 J/cm 2. Finally, the repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 – 61.0 J/cm 2.« less

Repair of a mirror coating on a large optic for high laser damage applications using ion milling and over-coating methods

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

Field, Ella S.; Bellum, John C.; Kletecka, Damon E.

Here, when an optical coating is damaged, deposited incorrectly, or is otherwise unsuitable, the conventional method to restore the optic often entails repolishing the optic surface, which can incur a large cost and long lead time. We propose three alternative options to repolishing, including (i) burying the unsuitable coating under another optical coating, (ii) using ion milling to etch the unsuitable coating completely from the optic surface and then recoating the optic, and (iii) using ion milling to etch through a number of unsuitable layers, leaving the rest of the coating intact, and then recoating the layers that were etched.more » Repairs were made on test optics with dielectric mirror coatings according to the above three options. The mirror coatings to be repaired were quarter wave stacks of HfO 2 and SiO 2 layers for high reflection at 1054 nm at 45 deg incidence in P-polarization. One of the coating layers was purposely deposited incorrectly as Hf metal instead of HfO2 to evaluate the ability of each repair method to restore the coating’s high laser-induced damage threshold (LIDT) of 64.0 J/cm 2. The repaired coating with the highest resistance to laser-induced damage was achieved using repair method (ii) with an LIDT of 49.0 to 61.0 J/cm 2.« less

Durable polymer-aerogel based superhydrophobic coatings, a composite material

DOEpatents

Kissel, David J; Brinker, Charles Jeffrey

2014-03-04

Provided are polymer-aerogel composite coatings, devices and articles including polymer-aerogel composite coatings, and methods for preparing the polymer-aerogel composite. The exemplary article can include a surface, wherein the surface includes at least one region and a polymer-aerogel composite coating disposed over the at least one region, wherein the polymer-aerogel composite coating has a water contact angle of at least about 140.degree. and a contact angle hysteresis of less than about 1.degree.. The polymer-aerogel composite coating can include a polymer and an ultra high water content catalyzed polysilicate aerogel, the polysilicate aerogel including a three dimensional network of silica particles having surface functional groups derivatized with a silylating agent and a plurality of pores.

Durable polymer-aerogel based superhydrophobic coatings: a composite material

DOEpatents

Kissel, David J.; Brinker, Charles Jeffrey

2016-02-02

Provided are polymer-aerogel composite coatings, devices and articles including polymer-aerogel composite coatings, and methods for preparing the polymer-aerogel composite. The exemplary article can include a surface, wherein the surface includes at least one region and a polymer-aerogel composite coating disposed over the at least one region, wherein the polymer-aerogel composite coating has a water contact angle of at least about 140.degree. and a contact angle hysteresis of less than about 1.degree.. The polymer-aerogel composite coating can include a polymer and an ultra high water content catalyzed polysilicate aerogel, the polysilicate aerogel including a three dimensional network of silica particles having surface functional groups derivatized with a silylating agent and a plurality of pores.

Synthesis and characterization of MoS2/Ti composite coatings on Ti6Al4V prepared by laser cladding

NASA Astrophysics Data System (ADS)

Yang, Rongjuan; Liu, Zongde; Wang, Yongtian; Yang, Guang; Li, Hongchuan

2013-02-01

The MoS2/Ti composite coating with sub-micron grade structure has been prepared on Ti6Al4V by laser method under argon protection. The morphology, microstructure, microhardness and friction coefficient of the coating were examined. The results indicated that the molybdenum disulfide was decomposed during melting and resolidification. The phase organization of composite coating mainly consisted of ternary element sulfides, molybdenum sulfides and titanium sulfides. The friction coefficient of and the surface roughness the MoS2/Ti coating were lower than those of Ti6Al4V. The composite coating exhibits excellent adhesion to the substrates, less surface roughness, good wear resistance and harder surface.

Methods of forming hardened surfaces

DOEpatents

Branagan, Daniel J [Iona, ID

2004-07-27

The invention encompasses a method of forming a metallic coating. A metallic glass coating is formed over a metallic substrate. After formation of the coating, at least a portion of the metallic glass can be converted into a crystalline material having a nanocrystalline grain size. The invention also encompasses metallic coatings comprising metallic glass. Additionally, the invention encompasses metallic coatings comprising crystalline metallic material, with at least some of the crystalline metallic material having a nanocrystalline grain size.

Amphiphilic polymer based on fluoroalkyl and PEG side chains for fouling release coating

NASA Astrophysics Data System (ADS)

Cong, W. W.; Wang, K.; Yu, X. Y.; Zhang, H. Q.; Lv, Z.; Gui, T. J.

2017-12-01

Under static conditions, fouling release coating could not express good release property to marine organisms. Amphiphilic polymer with mixture of fluorinated monomer and short side group of polyethylene glycol (PEG) was synthesized. And also we studied the ability of amphiphilic polymer to influence the surface properties and how it controlled the adhesion of marine organisms to coated surfaces. By incorporating fluorinated monomer and PEG side chain into the polymer, the effect of incorporating both polar and non-polar groups on fouling-release coating could be studied. The dry surface was characterized by three-dimensional digital microscopy and scanning electron microscopy (SEM), and the morphology of the amphiphilic fouling release coating showed just like flaky petal. The amphiphilic polymer in fouling release coating tended to reconstruct in water, and the ability was examined by static contact angle, which was smaller than the PDMS (polydimethylsiloxane) fouling release coating. Also surface energy was calculated by three solvents, and surface energy of amphiphilic fouling release coating was higher than that of the PDMS fouling release coating. To understand more about its fouling release property, seawater exposure method was adopted in gulf of Qingdao port. Fewer diatoms Navicula were found in biofilm after using amphiphilic fouling release coating. In general, coating containing both PEG and fluorinated side chain possessed certain fouling release property.

Robust Hydrophobic Surfaces from Suspension HVOF Thermal Sprayed Rare-Earth Oxide Ceramics Coatings.

PubMed

Bai, M; Kazi, H; Zhang, X; Liu, J; Hussain, T

2018-05-03

This study has presented an efficient coating method, namely suspension high velocity oxy-fuel (SHVOF) thermal spraying, to produce large super-hydrophobic ceramic surfaces with a unique micro- and nano-scale hierarchical structures to mimic natural super-hydrophobic surfaces. CeO 2 was selected as coatings material, one of a group of rare-earth oxide (REO) ceramics that have recently been found to exhibit intrinsic hydrophobicity, even after exposure to high temperatures and abrasive wear. Robust hydrophobic REO ceramic surfaces were obtained from the deposition of thin CeO 2 coatings (3-5 μm) using an aqueous suspension with a solid concentration of 30 wt.% sub-micron CeO 2 particles (50-200 nm) on a selection of metallic substrates. It was found that the coatings' hydrophobicity, microstructure, surface morphology, and deposition efficiency were all determined by the metallic substrates underneath. More importantly, it was demonstrated that the near super-hydrophobicity of SHVOF sprayed CeO 2 coatings was achieved not only by the intrinsic hydrophobicity of REO but also their unique hierarchically structure. In addition, the coatings' surface hydrophobicity was sensitive to the O/Ce ratio, which could explain the 'delayed' hydrophobicity of REO coatings.

Study on influence of Surface roughness of Ni-Al2O3 nano composite coating and evaluation of wear characteristics

NASA Astrophysics Data System (ADS)

Raghavendra, C. R.; Basavarajappa, S.; Sogalad, Irappa

2018-02-01

Electrodeposition is one of the most technologically feasible and economically superior techniques for producing metallic coating. The advancement in the application of nano particles has grabbed the attention in all fields of engineering. In this present study an attempt has been made on the Ni-Al2O3nano particle composite coating on aluminium substrate by electrodeposition process. The aluminium surface requires a specific pre-treatment for better adherence of coating. In light of this a thin zinc layer is coated on the aluminium substrate by electroless process. In addition to this surface roughness is an important parameter for any coating method and material. In this work Ni-Al2O3 composite coating were successfully coated by varying the process parameters such as bath temperature, current density and particle loading. The experimentation was performed using central composite design based 20 trials of experiments. The effect of process parameters and surface roughness before and after coating is analyzed on wear rate and coating thickness. The results shown a better wear resistance of Ni-Al2O3 composite electrodeposited coating compared to Ni coating. The particle loading and interaction effect of current density with temperature has greater significant effect on wear rate. The surface roughness is significantly affected the wear behaviour and thickness of coating.

Electrically isolated, high melting point, metal wire arrays and method of making same

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

Simpson, John T.; Cunningham, Joseph P.; D'Urso, Brian R.

2016-01-26

A method of making a wire array includes the step of providing a tube of a sealing material and having an interior surface, and positioning a wire in the tube, the wire having an exterior surface. The tube is heated to soften the tube, and the softened tube is drawn and collapsed by a mild vacuum to bring the interior surface of the tube into contact with the wire to create a coated wire. The coated wires are bundled. The bundled coated wires are heated under vacuum to fuse the tube material coating the wires and create a fused rodmore » with a wire array embedded therein. The fused rod is cut to form a wire array. A wire array is also disclosed.« less

Influence of Starting Powders on Hydroxyapatite Coatings Fabricated by Room Temperature Spraying Method.

PubMed

Seo, Dong Seok; Lee, Jong Kook; Hwang, Kyu Hong; Hahn, Byung Dong; Yoon, Seog Young

2015-08-01

Three types of raw materials were used for the fabrication of hydroxyapatite coatings by using the room temperature spraying method and their influence on the microstructure and in vitro characteristics were investigated. Starting hydroxyapatite powders for coatings on titanium substrate were prepared by a heat treatment at 1100 °C for 2 h of bovine bone, bone ash, and commercial hydroxyapatite powders. The phase compositions and Ca/P ratios of the three hydroxyapatite coatings were similar to those of the raw materials without decomposition or formation of a new phase. All hydroxyapatite coatings showed a honeycomb structure, but their surface microstructures revealed different features in regards to surface morphology and roughness, based on the staring materials. All coatings consisted of nano-sized grains and had dense microstructure. Inferred from in vitro experiments in pure water, all coatings have a good dissolution-resistance and biostability in water.

IN SITU Deposition of Fe-TiC Nanocomposite on Steel by Laser Cladding

NASA Astrophysics Data System (ADS)

Razavi, Mansour; Rahimipour, Mohammad Reza; Ganji, Mojdeh; Ganjali, Mansoreh; Gangali, Monireh

The possibility of deposition of Fe-TiC nanocomposite on the surface of carbon steel substrate with the laser coating method had been investigated. Mechanical milling was used for the preparation of raw materials. The mixture of milled powders was used as a coating material on the substrate steel surface and a CO2 laser was used in continuous mode for coating. Microstructural studies were performed by scanning electron microscopy. Determinations of produced phases, crystallite size and mean strain have been done by X-ray diffraction. The hardness and wear resistance of coated samples were measured. The results showed that the in situ formation of Fe-TiC nanocomposite coating using laser method is possible. This coating has been successfully used to improve the hardness and wear resistance of the substrate so that the hardness increased by about six times. Coated iron and titanium carbide crystallite sizes were in the nanometer scale.

The effects of floor incline on lower extremity biomechanics during unilateral landing from a jump in dancers.

PubMed

Pappas, Evangelos; Orishimo, Karl F; Kremenic, Ian; Liederbach, Marijeanne; Hagins, Marshall

2012-05-01

Retrospective studies have suggested that dancers performing on inclined ("raked") stages have increased injury risk. One study suggests that biomechanical differences exist between flat and inclined surfaces during bilateral landings; however, no studies have examined whether such differences exist during unilateral landings. In addition, little is known regarding potential gender differences in landing mechanics of dancers. Professional dancers (N = 41; 14 male, 27 female) performed unilateral drop jumps from a 30 cm platform onto flat and inclined surfaces while extremity joint angles and moments were identified and analyzed. There were significant joint angle and moment effects due to the inclined flooring. Women had significantly decreased peak ankle dorsiflexion and hip adduction moment compared with men. Findings of the current study suggest that unilateral landings on inclined stages create measurable changes in lower extremity biomechanical variables. These findings provide a preliminary biomechanical rationale for differences in injury rates found in observational studies of raked stages.

Determining bonding, thickness, and density via thermal wave impedance NDE

NASA Technical Reports Server (NTRS)

Green, D. R.

1985-01-01

Bonding, density, and thickness of coatings have a vital effect on their performance in many applications. Pioneering development work on thermal wave nondestructive evaluation (NDE) methods during the past 25 years has resulted in an array of useful techniques for performing bonding, density, and thickness measurements in a practical shop environment. The most useful thermal wave methods for this purpose are based on thermal wave surface impedance measurement or scanning. A pulse of heat from either a thermal transducer or a hot gas pulse is projected onto the surface, and the resulting temperature response is analyzed to unfold the bonding, density, and thickness of the coating. An advanced emissivity independent infrared method was applied to detect the temperature response. These methods were recently completely computerized and can automatically provide information on coating quality in near real-time using the proper equipment. Complex shapes such as turbine blades can be scanned. Microscopic inhomogeneities such as microstructural differences and small, normal, isolated voids do not cause problems but are seen as slight differences in the bulk thermal properties. Test objects with rough surfaces can be effectively nondestructively evaluated using proper thermal surface impedance methods. Some of the basic principles involved, as well as metallographic results illustrating the ability of the thermal wave surface impedance method to detect natural nonbonds under a two-layer thermally sprayed coating, will be presented.

Effects of hydroxyapatite/Zr and bioglass/Zr coatings on morphology and corrosion behaviour of Rex-734 alloy.

PubMed

Say, Y; Aksakal, B

2016-06-01

To improve corrosion resistance of metallic implant surfaces, Rex-734 alloy was coated with two different bio-ceramics; single-Hydroxyapatite (HA), double-HA/Zirconia(Zr) and double-Bioglass (BG)/Zr by using sol-gel method. Porous surface morphologies at low crack density were obtained after coating and sintering processes. Corrosion characteristics of coatings were determined by Open circuit potential and Potentiodynamic polarization measurements during corrosion tests. Hardness and adhesion strength of coating layers were measured and their surface morphologies before and after corrosion were characterized by scanning electron microscope (SEM), XRD and EDX. Through the SEM analysis, it was observed that corrosion caused degradation and sphere-like formations appeared with dimples on the coated surfaces. The coated substrates that exhibit high crack density, the corrosion was more effective by disturbing and transmitting through the coating layer, produced CrO3 and Cr3O8 oxide formation. It was found that the addition of Zr provided an increase in adhesion strength and corrosion resistance of the coatings. However, BG/Zr coatings had lower adhesion strength than the HA/Zr coatings, but showed higher corrosion resistance.

Low Temperature Metal Coating Method Final Report CRADA No. TSB-1155-95

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

Kang, Sang-Wook; Gabel, Howard

A new metal coating method, cidled KEM (kinetic energy metal.lization), demonstrated in the laboratory by lnovati, utilized fast-moving solid particIes entrained in a gas that are caused to fiow through a nozzIe to effect particle deposition on metal surfaces at room temperature conditions. This method (US Patent 5,795,626) was an attractive and viabIe alternative to the currentIy available high-temperature coating methods avaiIabIe. Since it differs significantly from existing metal coating technologies, a brief description of the method is incIuded here. The proposed method, KEM, achieves cohesive and adhesive metallurgical bonding through the high-speed coUision of powder with a substrate andmore » the subsequent discharge of electrical charge at the substrate. Such coating is effected by entraining metal powder in a gas and accelerating this mixture through a supersonic nozzle. The gas/powder is directed towards the substrate to be coated. Collisions occur, initiaIly between the powder and the substrate, and, as the first Iayer of the coating forms, between the powder and the coating. During these collisions the powder is rapidly deformed, causing the exposure of fresh (oxide free) active metal surface. When these’active surfaces contact one another, they agglomerate and form true metaIIurgicaI bonds. The resultant coating has Iow porosity and high adhesive and cohesive strength. The formation of metaIIurgicaI bonds is potentiated by the discharge of electrical energy. This electrical energy is the result of triboeIectric charging of the particIes during acceleration and transit to the nozzIe. An advantage of the method is that it does not raise the temperature of the powder being appLiedor that of the substrate. Consequently, materials sensitive to high temperature may be applied without changing Me properties of the materkd or substrate.« less

Processing on high efficiency solar collector coatings

NASA Technical Reports Server (NTRS)

Roberts, M.

1977-01-01

Wavelength selective coatings for solar collectors are considered. Substrates with good infrared reflectivity were examined along with their susceptibility to physical and environmental damage. Improvements of reflective surfaces were accomplished through buffing, chemical polishing and other surface processing methods.

Effect of triangular texture on the tribological performance of die steel with TiN coatings under lubricated sliding condition

NASA Astrophysics Data System (ADS)

Chen, Ping; Xiang, Xin; Shao, Tianmin; La, Yingqian; Li, Junling

2016-12-01

The friction and wear of stamping die surface can affect the service life of stamping die and the quality of stamping products. Surface texturing and surface coating have been widely used to improve the tribological performance of mechanical components. This study experimentally investigated the effect of triangular surface texture on the friction and wear properties of the die steel substrate with TiN coatings under oil lubrication. TiN coatings were deposited on a die steel (50Cr) substrate through a multi-arc ion deposition system, and then triangular surface texturing was fabricated by a laser surface texturing. The friction and wear test was conducted by a UMT-3 pin-on-disk tribometer under different sliding speeds and different applied loads, respectively. The adhesion test was performed to evaluate the effectiveness of triangular texturing on the interfacial bonding strength between the TiN coating and the die steel substrate. Results show that the combination method of surface texturing process and surface coating process has excellent tribological properties (the lowest frictional coefficient and wear volume), compared with the single texturing process or the single coating process. The tribological performance is improved resulting from the high hardness and low elastic modulus of TiN coatings, and the generation of hydrodynamic pressure, function of micro-trap for wear debris and micro-reservoirs for lubricating oil of the triangular surface texture. In addition, the coating bonding strength of the texturing sample is 3.63 MPa, higher than that of the single coating sample (3.48 MPa), but the mechanisms remain to be further researched.

Insect abatement system

NASA Technical Reports Server (NTRS)

Spiro, Clifford Lawrence (Inventor); Burnell, Timothy Brydon (Inventor); Wengrovius, Jeffrey Hayward (Inventor)

1997-01-01

An insect abatement system prevents adhesion of insect debris to surfaces which must be kept substantially free of insect debris. An article is coated with an insect abatement coating comprising polyorganosiloxane with a Shore A hardness of less than 50 and a tensile strength of less than 4 MPa. A method for preventing the adhesion of insect debris to surfaces includes the step of applying an insect abatement coating to a surface which must be kept substantially free of insect debris.

The effect of inclined soil layers on surface vibration from underground railways using a semi-analytical approach

NASA Astrophysics Data System (ADS)

Jones, S.; Hunt, H.

2009-08-01

Ground vibration due to underground railways is a significant source of disturbance for people living or working near the subways. The numerical models used to predict vibration levels have inherent uncertainty which must be understood to give confidence in the predictions. A semi-analytical approach is developed herein to investigate the effect of soil layering on the surface vibration of a halfspace where both soil properties and layer inclination angles are varied. The study suggests that both material properties and inclination angle of the layers have significant effect (± 10dB) on the surface vibration response.

Fabrication of a superhydrophobic surface with fungus-cleaning properties on brazed aluminum for industrial application in heat exchangers

NASA Astrophysics Data System (ADS)

Lee, Jeong-Won; Hwang, Woonbong

2018-06-01

Extensive research has been carried out concerning the application of superhydrophobic coating in heat exchangers, but little is known about the application of this technique to brazed aluminum heat exchangers (BAHEs). In this work, we describe a new superhydrophobic coating method, which is suitable for BAHE use on an industrial scale. We first render the BAHE superhydrophobic by fabricating micro/nanostructures using solution dipping followed by fluorination. After the complete removal of the silicon residue, we verify using surface analysis that the BAHE surface is perfectly superhydrophobic. We also studied the fungus-cleaning properties of the superhydrophobic surface by growing fungus for 4 weeks in a moist environment on BAHE fins with and without superhydrophobic coating. We observed that, whereas the fungus grown on the untreated fins is extremely difficult to remove, the fungus on the fins with the superhydrophobic coating can be removed easily with only a modest amount of water. We also found that the coated BAHE fins exhibit excellent resistance to moisture. The superhydrophobic coating method that we propose is therefore expected to have a major impact in the heating, ventilating and air conditioning industry market.

Technical note: Influence of surface roughness and local turbulence on coated-wall flow tube experiments for gas uptake and kinetic studies

NASA Astrophysics Data System (ADS)

Li, Guo; Su, Hang; Kuhn, Uwe; Meusel, Hannah; Ammann, Markus; Shao, Min; Pöschl, Ulrich; Cheng, Yafang

2018-02-01

Coated-wall flow tube reactors are frequently used to investigate gas uptake and heterogeneous or multiphase reaction kinetics under laminar flow conditions. Coating surface roughness may potentially distort the laminar flow pattern, induce turbulence and introduce uncertainties in the calculated uptake coefficient based on molecular diffusion assumptions (e.g., Brown/Cooney-Kim-Davis (CKD)/Knopf-Pöschl-Shiraiwa (KPS) methods), which has not been fully resolved in earlier studies. Here, we investigate the influence of surface roughness and local turbulence on coated-wall flow tube experiments for gas uptake and kinetic studies. According to laminar boundary theory and considering the specific flow conditions in a coated-wall flow tube, we derive and propose a critical height δc to evaluate turbulence effects in the design and analysis of coated-wall flow tube experiments. If a geometric coating thickness δg is larger than δc, the roughness elements of the coating may cause local turbulence and result in overestimation of the real uptake coefficient (γ). We further develop modified CKD/KPS methods (i.e., CKD-LT/KPS-LT) to account for roughness-induced local turbulence effects. By combination of the original methods and their modified versions, the maximum error range of γCKD (derived with the CKD method) or γKPS (derived with the KPS method) can be quantified and finally γ can be constrained. When turbulence is generated, γCKD or γKPS can bear large difference compared to γ. Their difference becomes smaller for gas reactants with lower uptake (i.e., smaller γ) and/or for a smaller ratio of the geometric coating thickness to the flow tube radius (δg / R0). On the other hand, the critical height δc can also be adjusted by optimizing flow tube configurations and operating conditions (i.e., tube diameter, length, and flow velocity), to ensure not only unaffected laminar flow patterns but also other specific requirements for an individual flow tube experiment. We use coating thickness values from previous coated-wall flow tube studies to assess potential roughness effects using the δc criterion. In most studies, the coating thickness was sufficiently small to avoid complications, but some may have been influenced by surface roughness and local turbulence effects.

The photoactivity of titanium dioxide coatings with silver nanoparticles prepared by sol-gel and reactive magnetron sputtering methods - comparative studies

NASA Astrophysics Data System (ADS)

Kądzioła, Kinga; Piwoński, Ireneusz; Kisielewska, Aneta; Szczukocki, Dominik; Krawczyk, Barbara; Sielski, Jan

2014-01-01

Titanium dioxide coatings were deposited on silicon substrates using two different methods: sol-gel dip-coating (SG) and reactive magnetron sputtering (MS). In order to obtain anatase phase, as-prepared coatings were calcined at 500 °C in air. Subsequently, silver nanoparticles (AgNPs) were grown on the surface of TiO2 coatings by photoreduction of silver ions, initiated by illumination of the UV lamp operated at λ = 365 nm. The concentrations of silver ions were 0.1 mmol dm-3 and 1.0 mmol dm-3. Coatings immersed in these solutions were illuminated during 5 min and 30 min. The coating thicknesses, evaluated by ellipsometry, were 118 nm and 147 nm for SG and MS methods, respectively. Atomic force microscopy (AFM) imaging revealed that the surface roughness of TiO2 coating prepared by MS is about 6 times larger as compared to coatings prepared by SG method. The size of AgNPs deposited on SG and MS coatings were in the range of 17-132 nm and 54-103 nm respectively. The photoactivity of AgNPs/TiO2 coatings was determined by the measurement of the decomposition rate of bisphenol A (BPA). The concentration of BPA before and after illumination under UV light (λ = 365 nm) was monitored by high-performance liquid chromatography (HPLC). It was found that AgNPs enhance the photoactivity of the TiO2 coatings.

Surface modification of tantalum pentoxide coatings deposited by magnetron sputtering and correlation with cell adhesion and proliferation in in vitro tests

NASA Astrophysics Data System (ADS)

Zykova, A.; Safonov, V.; Goltsev, A.; Dubrava, T.; Rossokha, I.; Donkov, N.; Yakovin, S.; Kolesnikov, D.; Goncharov, I.; Georgieva, V.

2016-03-01

The effect was analyzed of surface treatment by argon ions on the surface properties of tantalum pentoxide coatings deposited by reactive magnetron sputtering. The structural parameters of the as-deposited coatings were investigated by means of transmission electron microscopy, atomic force microscopy and scanning electron microscopy. X-ray diffraction profiles and X-ray photoelectron spectra were also acquired. The total surface free energy (SFE), the polar, dispersion parts and fractional polarities, were estimated by the Owens-Wendt-Rabel-Kaeble method. The adhesive and proliferative potentials of bone marrow cells were evaluated for both Ta2O5 coatings and Ta2O5 coatings deposited by simultaneous bombardment by argon ions in in vitro tests.

Surface studies on superhydrophobic and oleophobic polydimethylsiloxane-silica nanocomposite coating system

NASA Astrophysics Data System (ADS)

Basu, Bharathibai J.; Dinesh Kumar, V.; Anandan, C.

2012-11-01

Superhydrophobic and oleophobic polydimethylsiloxane (PDMS)-silica nanocomposite double layer coating was fabricated by applying a thin layer of low surface energy fluoroalkyl silane (FAS) as topcoat. The coatings exhibited WCA of 158-160° and stable oleophobic property with oil CA of 79°. The surface morphology was characterized by field emission scanning electron microscopy (FESEM) and surface chemical composition was determined by energy dispersive X-ray spectrometery (EDX) and X-ray photoelectron spectroscopy (XPS). FESEM images of the coatings showed micro-nano binary structure. The improved oleophobicity was attributed to the combined effect of low surface energy of FAS and roughness created by the random distribution of silica aggregates. This is a facile, cost-effective method to obtain superhydrophobic and oleophobic surfaces on larger area of various substrates.

Method of producing a carbon coated ceramic membrane and associated product

DOEpatents

Liu, Paul K. T.; Gallaher, George R.; Wu, Jeffrey C. S.

1993-01-01

A method of producing a carbon coated ceramic membrane including passing a selected hydrocarbon vapor through a ceramic membrane and controlling ceramic membrane exposure temperature and ceramic membrane exposure time. The method produces a carbon coated ceramic membrane of reduced pore size and modified surface properties having increased chemical, thermal and hydrothermal stability over an uncoated ceramic membrane.

Nanosilica coating for bonding improvements to zirconia.

PubMed

Chen, Chen; Chen, Gang; Xie, Haifeng; Dai, Wenyong; Zhang, Feimin

2013-01-01

Resin bonding to zirconia cannot be established from standard methods that are currently utilized in conventional silica-based dental ceramics. The solution-gelatin (sol-gel) process is a well developed silica-coating technique used to modify the surface of nonsilica-based ceramics. Here, we use this technique to improve resin bonding to zirconia, which we compared to zirconia surfaces treated with alumina sandblasting and tribochemical silica coating. We used the shear bond strength test to examine the effect of the various coatings on the short-term resin bonding of zirconia. Furthermore, we employed field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, and Fourier transform infrared spectroscopy to characterize the zirconia surfaces. Water-mist spraying was used to evaluate the durability of the coatings. To evaluate the biological safety of the experimental sol-gel silica coating, we conducted an in vitro Salmonella typhimurium reverse mutation assay (Ames mutagenicity test), cytotoxicity tests, and in vivo oral mucous membrane irritation tests. When compared to the conventional tribochemical silica coating, the experimental sol-gel silica coating provided the same shear bond strength, higher silicon contents, and better durability. Moreover, we observed no apparent mutagenicity, cytotoxicity, or irritation in this study. Therefore, the sol-gel technique represents a promising method for producing silica coatings on zirconia.

Nanosilica coating for bonding improvements to zirconia

PubMed Central

Chen, Chen; Chen, Gang; Xie, Haifeng; Dai, Wenyong; Zhang, Feimin

2013-01-01

Resin bonding to zirconia cannot be established from standard methods that are currently utilized in conventional silica-based dental ceramics. The solution–gelatin (sol–gel) process is a well developed silica-coating technique used to modify the surface of nonsilica-based ceramics. Here, we use this technique to improve resin bonding to zirconia, which we compared to zirconia surfaces treated with alumina sandblasting and tribochemical silica coating. We used the shear bond strength test to examine the effect of the various coatings on the short-term resin bonding of zirconia. Furthermore, we employed field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, atomic force microscopy, and Fourier transform infrared spectroscopy to characterize the zirconia surfaces. Water–mist spraying was used to evaluate the durability of the coatings. To evaluate the biological safety of the experimental sol–gel silica coating, we conducted an in vitro Salmonella typhimurium reverse mutation assay (Ames mutagenicity test), cytotoxicity tests, and in vivo oral mucous membrane irritation tests. When compared to the conventional tribochemical silica coating, the experimental sol–gel silica coating provided the same shear bond strength, higher silicon contents, and better durability. Moreover, we observed no apparent mutagenicity, cytotoxicity, or irritation in this study. Therefore, the sol–gel technique represents a promising method for producing silica coatings on zirconia. PMID:24179333

Increased Alignment in Carbon Nanotube Growth

NASA Technical Reports Server (NTRS)

Delzeit, Lance D. (Inventor)

2007-01-01

Method and system for fabricating an array of two or more carbon nanotube (CNT) structures on a coated substrate surface, the structures having substantially the same orientation with respect to a substrate surface. A single electrode, having an associated voltage source with a selected voltage, is connected to a substrate surface after the substrate is coated and before growth of the CNT structures, for a selected voltage application time interval. The CNT structures are then grown on a coated substrate surface with the desired orientation. Optionally, the electrode can be disconnected before the CNT structures are grown.

Is drop impact the same for both moving and inclined surfaces?

NASA Astrophysics Data System (ADS)

Buksh, Salman; Marengo, Marco; Amirfazli, Alidad; -Team

2017-11-01

Drop impact is an important phenomenon in a wide variety of applications. Researchers have largely examined drop impact onto a moving surface, and an inclined surface separately. Given that in both systems the impact phenomenon is influenced by tangential and normal velocity components, the question remains, if these two systems are essentially equivalent or gravity and boundary layer effects are such that the outcomes will be different. Experiments have been performed by varying liquid surface tension, viscosity and both normal and tangential velocities (0.3 to 2.9 m/s). The desired velocity components were achieved by changing the height where drop is released, the surface inclination angle for inclined system, and the horizontal velocity for the moving surface. To compare the systems, spreading was analyzed by measuring the width and length of the lamella at various time intervals; for splashing, top view images were compared to see the extent of splashing at initial stage. The data suggests that, for the given velocity, neither the boundary layer differences between the two systems nor the gravity play a role on spreading and splashing of the drop, as such one system can replace the other for future studies.

Method for forming a hardened surface on a substrate

DOEpatents

Branagan, Daniel J [Iona, ID

2008-01-29

The invention encompasses a method of forming a metallic coating. A metallic glass coating is formed over a metallic substrate. After formation of the coating, at least a portion of the metallic glass can be converted into a crystalline material having a nanocrystalline grain size. The invention also encompasses metallic coatings comprising metallic glass. Additionally, the invention encompasses metallic coatings comprising crystalline metallic material, with at least some of the crystalline metallic material having a nanocrystalline grain size.

Solventless dry powder coating for sustained drug release using mechanochemical treatment based on the tri-component system of acetaminophen, carnauba wax and glidant.

PubMed

Hoashi, Yohei; Tozuka, Yuichi; Takeuchi, Hirofumi

2013-02-01

Solventless dry powder coating methods have many advantages compared to solvent-based methods: they are more economical, simpler, safer, more environmentally friendly and easier to scale up. The purpose of this study was to investigate a highly effective dry powder coating method using the mechanofusion system, a mechanochemical treatment equipped with high compressive and shearing force. Acetaminophen (AAP) and carnauba wax (CW) were selected as core particles of the model drug and coating material, respectively. Mixtures of AAP and CW with and without talc were processed using the mechanofusion system. Sustained AAP release was observed by selecting appropriate processing conditions for the rotation speed and the slit size. The dissolution rate of AAP processed with CW substantially decreased with an increase in talc content up to 40% of the amount of CW loaded. Increasing the coating amount by two-step addition of CW led to more effective coating and extended drug release. Scanning electron micrographs indicated that CW adhered and showed satisfactory coverage of the surface of AAP particles. Effective CW coating onto the AAP surface was successfully achieved by strictly controlling the processing conditions and the composition of core particles, coating material and glidant. Our mechanochemical dry powder coating method using the mechanofusion system is a simple and promising means of solventless pharmaceutical coating.

Antibacterial and anticancer PDMS surface for mammalian cell growth using the Chinese herb extract paeonol(4-methoxy-2-hydroxyacetophenone)

NASA Astrophysics Data System (ADS)

Jiao, Jiajia; Sun, Lili; Guo, Zaiyu; Hou, Sen; Holyst, Robert; Lu, Yun; Feng, Xizeng

2016-12-01

Polydimethylsiloxane (PDMS) is widely used as a cell culture platform to produce micro- and nano-technology based microdevices. However, the native PDMS surface is not suitable for cell adhesion and is always subject to bacterial pollution and cancer cell invasion. Coating the PDMS surface with antibacterial or anticancer materials often causes considerable harm to the non-cancer mammalian cells on it. We have developed a method to fabricate a biocompatible PDMS surface which not only promotes non-cancer mammalian cell growth but also has antibacterial and anticancer activities, by coating the PDMS surface with a Chinese herb extract, paeonol. Coating changes the wettability and the elemental composition of the PDMS surface. Molecular dynamic simulation indicates that the absorption of paeonol onto the PDMS surface is an energy favourable process. The paeonol-coated PDMS surface exhibits good antibacterial activity against both Gram-positive and Gram-negative bacteria. Moreover considerable antibacterial activity is maintained after the coated surface is rinsed or incubated in water. The coated PDMS surface inhibits bacterial growth on the contact surface and promotes non-cancer mammalian cell growth with low cell toxicity; meanwhile the growth of cancer cells is significantly inhibited. Our study will potentially guide PDMS surface modification approaches to produce biomedical devices.

Heat transfer enhancement induced by wall inclination in turbulent thermal convection

NASA Astrophysics Data System (ADS)

Kenjereš, Saša

2015-11-01

We present a series of numerical simulations of turbulent thermal convection of air in an intermediate range or Rayleigh numbers (106≤Ra ≤109 ) with different configurations of a thermally active lower surface. The geometry of the lower surface is designed in such a way that it represents a simplified version of a mountain slope with different inclinations (i.e., "Λ "- and "V "-shaped geometry). We find that different wall inclinations significantly affect the local heat transfer by imposing local clustering of instantaneous thermal plumes along the inclination peaks. The present results reveal that significant enhancement of the integral heat transfer can be obtained (up to 32%) when compared to a standard Rayleigh-Bénard configuration with flat horizontal walls. This is achieved through combined effects of the enlargement of the heated surface and reorganization of the large-scale flow structures.

Some investigations on the enhancement of boiling heat transfer from planer surface embedded with continuous open tunnels

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

Das, A.K.; Das, P.K.; Saha, P.

2010-11-15

Boiling heat transfer from a flat surface can be enhanced if continuous open tunnel type structures are embedded in it. Further, improvement of boiling heat transfer from such surfaces has been tried by two separate avenues. At first, inclined tunnels are embedded over the solid surface and an effort is made to optimize the tunnel inclination for boiling heat transfer. Surfaces are manufactured in house with four different inclinations of the tunnels with or without a reentrant circular pocket at the end of the tunnel. Experiments conducted in the nucleate boiling regime showed that 45 deg inclination of the tunnelsmore » for both with and without base geometry provides the highest heat transfer coefficient. Next, active fluid rotation was imposed to enhance the heat transfer from tunnel type surfaces with and without the base geometry. Rotational speed imparted by mechanical stirrer was varied over a wide range. It was observed that fluid rotation enhances the heat transfer coefficient only up to a certain value of stirrer speed. Rotational speed values, beyond this limit, reduce the boiling heat transfer severely. A comparison shows that embedding continuous tunnel turns out to be a better option for the increase of heat transfer coefficient compared to the imposition of fluid rotation. But the behavior of inclined tunnels under the action of fluid rotation is yet to be established and can be treated as a future scope of the work. (author)« less

Study of the Effect of Molten Copper Chloride Immersion Test on Alloys with High Nickel Content with and without Surface Coatings

NASA Astrophysics Data System (ADS)

Siantar, Edwin

The demand for hydrogen as a clean energy carrier has increased greatly. The Cu-Cl cycle is a promising thermochemical cycle that is currently being developed to be the large-scale method of hydrogen production. The lifetime of materials for the pipes transporting molten CuCl is an important parameter for an economic design of a commercial thermochemical Cu-Cl hydrogen plant. This research is an examination of candidate materials following an immersion test in molten CuCl at 500 °C for 100 h. Two alloys, Ni based super-alloy (Inconel 625) and super austenitic stainless steel (AL6XN) were selected as the base metal. There were two types of coating applied to improve the corrosion resistance of the base metals during molten CuCl exposure. A metallic of Diamalloy 4006 and two ceramic of yttria stabilized zirconia and alumina coatings were applied to the base metal using thermal spray methods. An immersion apparatus was designed and constructed to perform an immersion test that has a condition similar to those in a hydrogen plant. After the immersion test, the materials were evaluated using an electrochemical method in combination with ex-situ surface analysis. The surface condition including elemental composition, film structure and resistivity of the materials were examined and compared. The majority of the coatings were damaged and fell off. Cracks were found in the original coated specimens indicating the sample geometry may have affected the integrity of the sprayed coating. When the coating cracked, it provided a pathway for the molten CuCl to go under the coating and react with the surface underneath the coating. Copper deposits and iron chloride that were found on the sample surfaces suggest that there were corrosion reactions that involved the metal dissolution and reduction of copper during immersion test. The results also suggest that Inconel 625 performed better than stainless steel AL6XN. Both Diamalloy 4006 and YSZ (ZrO2 18TiO2 10Y2O3) coatings seemed to provide better protection to the underlying base metal than alumina (Al2O3 3TiO2) coating.

Method of forming a continuous polymeric skin on a cellular foam material

DOEpatents

Duchane, David V.; Barthell, Barry L.

1985-01-01

Hydrophobic cellular material is coated with a thin hydrophilic polymer skin which stretches tightly over the outer surface of the foam but which does not fill the cells of the foam, thus resulting in a polymer-coated foam structure having a smoothness which was not possible in the prior art. In particular, when the hydrophobic cellular material is a specially chosen hydrophobic polymer foam and is formed into arbitrarily chosen shapes prior to the coating with hydrophilic polymer, inertial confinement fusion (ICF) targets of arbitrary shapes can be produced by subsequently coating the shapes with metal or with any other suitable material. New articles of manufacture are produced, including improved ICF targets, improved integrated circuits, and improved solar reflectors and solar collectors. In the coating method, the cell size of the hydrophobic cellular material, the viscosity of the polymer solution used to coat, and the surface tensin of the polymer solution used to coat are all very important to the coating.

Method and apparatus for measuring on-line failure of turbine thermal barrier coatings

DOEpatents

Zombo, Paul J.; Lemieux, Dennis; Diatzikis, Evangelos

2010-04-06

A method of remotely monitoring the radiant energy (6) emitted from a turbine component such as a turbine blade (1) having a low-reflective surface coating (3) which may be undergoing potential degradation is used to determine whether erosion, spallation, delamination, or the like, of the coating (3) is occurring.

Method of Obtaining Uniform Coatings on Graphite

DOEpatents

Campbell, I. E.

1961-04-01

A method is given for obtaining uniform carbide coatings on graphite bodies. According to the invention a metallic halide in vapor form is passed over the graphite body under such conditions of temperature and pressure that the halide reacts with the graphite to form a coating of the metal carbide on the surface of the graphite.

METHOD OF OBTAINING UNIFORM COATINGS ON GRAPHITE

DOEpatents

Campbell, I.E.

1961-04-01

A method is given for obtaining uniform carbide coatings on graphite bodies. According to the invention a metallic halide in vapor form is passed over the graphite body under such conditions of temperature and pressure that the halide reacts with the graphite to form a coating of the metal carbide on the surface of the graphite.

Surface Coating of Gypsum-Based Molds for Maxillofacial Prosthetic Silicone Elastomeric Material: The Surface Topography.

PubMed

Khalaf, Salah; Ariffin, Zaihan; Husein, Adam; Reza, Fazal

2015-07-01

This study aimed to compare the surface roughness of maxillofacial silicone elastomers fabricated in noncoated and coated gypsum materials. This study was also conducted to characterize the silicone elastomer specimens after surfaces were modified. A gypsum mold was coated with clear acrylic spray. The coated mold was then used to produce modified silicone experimental specimens (n = 35). The surface roughness of the modified silicone elastomers was compared with that of the control specimens, which were prepared by conventional flasking methods (n = 35). An atomic force microscope (AFM) was used for surface roughness measurement of silicone elastomer (unmodified and modified), and a scanning electron microscope (SEM) was used to evaluate the topographic conditions of coated and noncoated gypsum and silicone elastomer specimens (unmodified and modified) groups. After the gypsum molds were characterized, the fabricated silicone elastomers molded on noncoated and coated gypsum materials were evaluated further. Energy-dispersive X-ray spectroscopy (EDX) analysis of gypsum materials (noncoated and coated) and silicone elastomer specimens (unmodified and modified) was performed to evaluate the elemental changes after coating was conducted. Independent t test was used to analyze the differences in the surface roughness of unmodified and modified silicone at a significance level of p < 0.05. Roughness was significantly reduced in the silicone elastomers processed against coated gypsum materials (p < 0.001). The AFM and SEM analysis results showed evident differences in surface smoothness. EDX data further revealed the presence of the desired chemical components on the surface layer of unmodified and modified silicone elastomers. Silicone elastomers with lower surface roughness of maxillofacial prostheses can be obtained simply by coating a gypsum mold. © 2014 by the American College of Prosthodontists.

Determination of surface energies of hot-melt extruded sugar-starch pellets.

PubMed

Yeung, Chi-Wah; Rein, Hubert

2018-02-01

Hot-melt extruded sugar-starch pellets are an alternative for commercial sugar spheres, but their coating properties remain to be studied. Both the European Pharmcopoeia 8.6 and the United States Pharmacopoeia 40 specify the composition of sugar-starch pellets without giving requirements for the manufacturing process. Due to various fabrication techniques, the physicochemical properties of pellets may differ. Therefore, the adhesion energies of three coating dispersions (sustained, enteric and immediate release) on different types of pellets were investigated. In this context, the surface energies of various kinds of corn starch (normal, waxy, high-amylose) and sucrose pellets were analyzed using the sessile drop method, whereas the surface tensions of the coating dispersions were examined using the pendant drop method. The adhesion forces were calculated from the results of these studies. Furthermore, sugar spheres were characterized in terms of particle size distribution, porosity and specific surface area. An increase of the pellets' sucrose content leads to a more porous surface structure, which gives them an enhanced wetting behavior with coating dispersions. The adhesion energies of extruded sugar-starch pellets are similar to those of commercial sugar spheres, which comply with pharmacopeial requirements. Both types of pellets are equally suited for coating.

Study of sporadical properties of crosslinked polyelectrolyte multilayers

NASA Astrophysics Data System (ADS)

Balu, Deebika

Polyelectrolyte multilayers (PEM) have become a highly studied class of materials due to the range of their applicability in many areas of research, including biology, chemistry and materials science. Recent advances in surface coatings have enabled modification of PEM surfaces to provide desirable properties such as controlled release, super-hydrophobicity, biocompatibility, antifouling and antibacterial properties. In the past decade, antimicrobial PEM coatings have been investigated as a safer alternative to the traditional disinfection methods that usually involve application of hazardous chemicals onto the surface to be cleaned. These antimicrobial coatings could be applied to common surfaces prone to colonization of bacteria (such as bench tops, faucet handles, etc) to supplement routine sanitization protocols by providing sustained antimicrobial activity. Vegetative bacteria (such as Escherichia coli) are more susceptible to antimicrobial agents than bacterial species that form spores. Hence, the antimicrobial activity of PEM coatings fabricated using Layer by Layer (LbL) technique were assayed using Bacillus anthracis spores (Sterne strain). In this thesis, the sporicidal effect of various polyelectrolyte multilayer coatings containing cross-linked polymers immersed in bleach have been evaluated as potential augmentation to existing disinfection methods.

Maximum likelihood solution for inclination-only data in paleomagnetism

NASA Astrophysics Data System (ADS)

Arason, P.; Levi, S.

2010-08-01

We have developed a new robust maximum likelihood method for estimating the unbiased mean inclination from inclination-only data. In paleomagnetic analysis, the arithmetic mean of inclination-only data is known to introduce a shallowing bias. Several methods have been introduced to estimate the unbiased mean inclination of inclination-only data together with measures of the dispersion. Some inclination-only methods were designed to maximize the likelihood function of the marginal Fisher distribution. However, the exact analytical form of the maximum likelihood function is fairly complicated, and all the methods require various assumptions and approximations that are often inappropriate. For some steep and dispersed data sets, these methods provide estimates that are significantly displaced from the peak of the likelihood function to systematically shallower inclination. The problem locating the maximum of the likelihood function is partly due to difficulties in accurately evaluating the function for all values of interest, because some elements of the likelihood function increase exponentially as precision parameters increase, leading to numerical instabilities. In this study, we succeeded in analytically cancelling exponential elements from the log-likelihood function, and we are now able to calculate its value anywhere in the parameter space and for any inclination-only data set. Furthermore, we can now calculate the partial derivatives of the log-likelihood function with desired accuracy, and locate the maximum likelihood without the assumptions required by previous methods. To assess the reliability and accuracy of our method, we generated large numbers of random Fisher-distributed data sets, for which we calculated mean inclinations and precision parameters. The comparisons show that our new robust Arason-Levi maximum likelihood method is the most reliable, and the mean inclination estimates are the least biased towards shallow values.

Synergistic Effect of Superhydrophobicity and Oxidized Layers on Corrosion Resistance of Aluminum Alloy Surface Textured by Nanosecond Laser Treatment.

PubMed

Boinovich, Ludmila B; Emelyanenko, Alexandre M; Modestov, Alexander D; Domantovsky, Alexandr G; Emelyanenko, Kirill A

2015-09-02

We report a new efficient method for fabricating a superhydrophobic oxidized surface of aluminum alloys with enhanced resistance to pitting corrosion in sodium chloride solutions. The developed coatings are considered very prospective materials for the automotive industry, shipbuilding, aviation, construction, and medicine. The method is based on nanosecond laser treatment of the surface followed by chemisorption of a hydrophobic agent to achieve the superhydrophobic state of the alloy surface. We have shown that the surface texturing used to fabricate multimodal roughness of the surface may be simultaneously used for modifying the physicochemical properties of the thick surface layer of the substrate itself. Electrochemical and wetting experiments demonstrated that the superhydrophobic state of the metal surface inhibits corrosion processes in chloride solutions for a few days. However, during long-term contact of a superhydrophobic coating with a solution, the wetted area of the coating is subjected to corrosion processes due to the formation of defects. In contrast, the combination of an oxide layer with good barrier properties and the superhydrophobic state of the coating provides remarkable corrosion resistance. The mechanisms for enhancing corrosion protective properties are discussed.

Theoretical analysis of optical properties of dielectric coatings dependence on substrate subsurface defects

NASA Astrophysics Data System (ADS)

Shen, Jian; Liu, Shouhua; Shen, Zicai; Shao, Jianda; Fan, Zhengxiu

2006-03-01

A model for refractive index of stratified dielectric substrate was put forward according to theories of inhomogeneous coatings. The substrate was divided into surface layer, subsurface layer and bulk layer along the normal direction of its surface. Both the surface layer (separated into N1 sublayers of uniform thickness) and subsurface layer (separated into N2 sublayers of uniform thickness), whose refractive indices have different statistical distributions, are equivalent to inhomogeneous coatings, respectively. And theoretical deduction was carried out by employing characteristic matrix method of optical coatings. An example of mathematical calculation for optical properties of dielectric coatings had been presented. The computing results indicate that substrate subsurface defects can bring about additional bulk scattering and change propagation characteristic in thin film and substrate. Therefore, reflectance, reflective phase shift and phase difference of an assembly of coatings and substrate deviate from ideal conditions. The model will provide some beneficial theory directions for improving optical properties of dielectric coatings via substrate surface modification.

Carbide coated fibers in graphite-aluminum composites

NASA Technical Reports Server (NTRS)

Imprescia, R. J.; Levinson, L. S.; Reiswig, R. D.; Wallace, T. C.; Williams, J. M.

1975-01-01

The study of protective-coupling layers of refractory metal carbides on the graphite fibers prior to their incorporation into composites is presented. Such layers should be directly wettable by liquid aluminum and should act as diffusion barriers to prevent the formation of aluminum carbide. Chemical vapor deposition was used to uniformly deposit thin, smooth, continuous coats of ZrC on the carbon fibers of tows derived from both rayon and polyacrylonitrile. A wet chemical coating of the fibers, followed by high-temperature treatment, was used, and showed promise as an alternative coating method. Experiments were performed to demonstrate the ability of aluminum alloys to wet carbide surfaces. Titanium carbide, zirconium carbide and carbide-coated graphite surfaces were successfully wetted. Results indicate that initial attempts to wet surfaces of ZrC-coated carbon fibers appear successful.

IRON COATED URANIUM AND ITS PRODUCTION

DOEpatents

Gray, A.G.

1960-03-15

A method of applying a protective coating to a metallic uranium article is given. The method comprises etching the surface of the article with an etchant solution containlng chloride ions, such as a solution of phosphoric acid and hydrochloric acid, cleaning the etched surface, electroplating iron thereon from a ferrous ammonium sulfate electroplating bath, and soldering an aluminum sheath to the resultant iron layer.

Surface modification of polypropylene based particle foams

NASA Astrophysics Data System (ADS)

Schreier, P.; Trassl, C.; Altstädt, V.

2014-05-01

This paper deals with the modification of the surface properties of expanded polypropylene (EPP). EPP is a semi-hard to soft elastic thermoplastic foam. The characteristic surface of EPP shows process-related steam nozzle imprints and gussets. Therefore EPP does not satisfy the quality requirements for visible automotive applications. In order to meet these demands, plastic surfaces are usually enhanced with functional or decorative coatings, e.g. textiles, plastic films or paint. The coating of plastics with low surface energies such as PP often leads to adhesion problems by reason of the missing polar and functional groups. This paper gives an evaluation of activation and pre-treatment methods of EPP, with the aim to identify the most suitable pre-treatment method. For this purpose five typical surface treatment methods - flame treatment, corona, fluorination, atmospheric and low-pressure plasma - were performed on EPP samples. As a comparison criterion the maximum increase in the adhesion force between a polyurethane-based coating and the modified EPP substrate was selected. Moreover the influence of the selected pre-treatment method on the increase in the total surface energy and its polar component was investigated by the drop shape analysis method. The results showed that the contact angle measurement is a suitable method to determine the polar and disperse fractions of the surface tension of EPP. Furthermore, all performed methods increased the adhesion of EPP.

Fortifying the Bone-Implant Interface Part 1: An In Vitro Evaluation of 3D-Printed and TPS Porous Surfaces

PubMed Central

Lindsey, Derek P.; Bahney, Chelsea S.; Woods, Shane A.; Wolfe, Mark L.; Yerby, Scott A.

2017-01-01

Background An aging society and concomitant rise in the incidence of impaired bone health have led to the need for advanced osteoconductive spinal implant surfaces that promote greater biological fixation (e.g. for interbody fusion cages, sacroiliac joint fusion implants, and artificial disc replacements). Additive manufacturing, i.e. 3D-printing, may improve bone integration by generating biomimetic spinal implant surfaces that mimic bone morphology. Such surfaces may foster an enhanced cellular response compared to traditional implant surfacing processes. Methods This study investigated the response of human osteoblasts to additive manufactured (AM) trabecular-like titanium implant surfaces compared to traditionally machined base material with titanium plasma spray (TPS) coated surfaces, with and without a nanocrystalline hydroxyapatite (HA) coating. For TPS-coated discs, wrought Ti6Al4V ELI was machined and TPS-coating was applied. For AM discs, Ti6Al4V ELI powder was 3D-printed to form a solid base and trabecular-like porous surface. The HA-coating was applied via a precipitation dip-spin method. Surface porosity, pore size, thickness, and hydrophilicity were characterized. Initial cell attachment, proliferation, alkaline phosphatase (ALP) activity, and calcium production of hFOB cells (n=5 per group) were measured. Results Cells on AM discs exhibited expedited proliferative activity. While there were no differences in mean ALP expression and calcium production between TPS and AM discs, calcium production on the AM discs trended 48% higher than on TPS discs (p=0.07). Overall, HA-coating did not further enhance results compared to uncoated TPS and AM discs. Conclusions Results demonstrate that additive manufacturing allows for controlled trabecular-like surfaces that promote earlier cell proliferation and trends toward higher calcium production than TPS coating. Results further showed that nanocrystalline HA may not provide an advantage on porous titanium surfaces. Clinical Relevance Additive manufactured porous titanium surfaces may induce a more osteogenic environment compared to traditional TPS, and thus present as an attractive alternative to TPS-coating for orthopedic spinal implants. PMID:28765799

Nano-Ag-loaded hydroxyapatite coatings on titanium surfaces by electrochemical deposition

PubMed Central

Lu, Xiong; Zhang, Bailin; Wang, Yingbo; Zhou, Xianli; Weng, Jie; Qu, Shuxin; Feng, Bo; Watari, Fumio; Ding, Yonghui; Leng, Yang

2011-01-01

Hydroxyapatite (HA) coatings on titanium (Ti) substrates have attracted much attention owing to the combination of good mechanical properties of Ti and superior biocompatibility of HA. Incorporating silver (Ag) into HA coatings is an effective method to impart the coatings with antibacterial properties. However, the uniform distribution of Ag is still a challenge and Ag particles in the coatings are easy to agglomerate, which in turn affects the applications of the coatings. In this study, we employed pulsed electrochemical deposition to co-deposit HA and Ag simultaneously, which realized the uniform distribution of Ag particles in the coatings. This method was based on the use of a well-designed electrolyte containing Ag ions, calcium ions and l-cysteine, in which cysteine acted as the coordination agent to stabilize Ag ions. The antibacterial and cell culture tests were used to evaluate the antibacterial properties and biocompatibility of HA/Ag composite coatings, respectively. The results indicated the as-prepared coatings had good antibacterial properties and biocompatibility. However, an appropriate silver content should be chosen to balance the biocompatibility and antibacterial properties. Heat treatments promoted the adhesive strength and enhanced the biocompatibility without sacrificing the antibacterial properties of the HA/Ag coatings. In summary, this study provided an alternative method to prepare bioactive surfaces with bactericidal ability for biomedical devices. PMID:20880853

Sci-Sat AM: Radiation Dosimetry and Practical Therapy Solutions - 02: Dosimetric effects of gold nanoparticle surface coatings

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

Koger, Brandon; Kirkby, Charles

2016-08-15

Introduction: Gold nanoparticles (GNPs) can enhance radiation therapy within a tumour, increasing local energy deposition under irradiation, but experimental evidence suggests the enhancement is not as large as predicted by dose enhancement alone. Many studies neglect to account for surface coatings that are frequently used to optimize GNP uptake and biological distribution. This study uses Monte Carlo methods to investigate the consequences on local dose enhancement due to including these surface coatings. Methods: Using the PENELOPE Monte Carlo code system, GNP irradiation was simulated both with and without surface coatings of polyethylene glycol (PEG) of various molecular weights. Dose wasmore » scored to the gold, coating, and surrounding water, and the dosimetric differences between these scenarios were examined. Results: The simulated PEG coating absorbs a large portion of the energy that would otherwise be deposited in the medium. The mean dose to water was reduced by up to 2.5, 3.5, and 4.5% for GNPs of diameters 50, 20, and 10 nm, respectively. This effect was more pronounced for smaller GNPs, thicker coatings, and low photon source energies where the enhancement due to GNPs is the greatest. The molecular weight of the coating material did not have a significant impact on the dose. Conclusions: The inclusion of a coating material in GNP enhanced radiation may reduce the dose enhancement due to the nanoparticles. Both the composition and size of the coating play a role in the level of this reduction and should be considered carefully.« less

The Valgus Inclination of the Tibial Component Increases the Risk of Medial Tibial Condylar Fractures in Unicompartmental Knee Arthroplasty.

PubMed

Inoue, Shinji; Akagi, Masao; Asada, Shigeki; Mori, Shigeshi; Zaima, Hironori; Hashida, Masahiko

2016-09-01

Medial tibial condylar fractures (MTCFs) are a rare but serious complication after unicompartmental knee arthroplasty. Although some surgical pitfalls have been reported for MTCFs, it is not clear whether the varus/valgus tibial inclination contributes to the risk of MTCFs. We constructed a 3-dimensional finite elemental method model of the tibia with a medial component and assessed stress concentrations by changing the inclination from 6° varus to 6° valgus. Subsequently, we repeated the same procedure adding extended sagittal bone cuts of 2° and 10° in the posterior tibial cortex. Furthermore, we calculated the bone volume that supported the tibial component, which is considered to affect stress distribution in the medial tibial condyle. Stress concentrations were observed on the medial tibial metaphyseal cortices and on the anterior and posterior tibial cortices in the corner of cut surfaces in all models; moreover, the maximum principal stresses on the posterior cortex were larger than those on the anterior cortex. The extended sagittal bone cuts in the posterior tibial cortex increased the stresses further at these 3 sites. In the models with a 10° extended sagittal bone cut, the maximum principal stress on the posterior cortex increased as the tibial inclination changed from 6° varus to 6° valgus. The bone volume decreased as the inclination changed from varus to valgus. In this finite element method, the risk of MTCFs increases with increasing valgus inclination of the tibial component and with increased extension of the sagittal cut in the posterior tibial cortex. Copyright © 2016 Elsevier Inc. All rights reserved.

Vapor deposition on doublet airfoil substrates: Control of coating thickness and microstructure

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

Rodgers, Theron M.; Zhao, Hengbei; Wadley, Haydn N. G., E-mail: haydn@virginia.edu

Gas jet assisted vapor deposition processes for depositing coatings are conducted at higher pressures than conventional physical vapor deposition methods, and have shown promise for coating complex shaped substrates including those with non-line-of-sight (NLS) regions on their surface. These regions typically receive vapor atoms at a lower rate and with a wider incident angular distribution than substrate regions in line-of-sight (LS) of the vapor source. To investigate the coating of such substrates, the thickness and microstructure variation along the inner (curved) surfaces of a model doublet airfoil containing both LS and NLS regions has been investigated. Results from atomistic simulationsmore » and experiments confirm that the coating's thickness is thinner in flux-shadowed regions than in other regions for all the coating processes investigated. They also indicated that the coatings columnar microstructure and pore volume fraction vary with surface location through the LS to NLS transition zone. A substrate rotation strategy for optimizing the thickness over the entire doublet airfoil surface was investigated, and led to the identification of a process that resulted in only small variation of coating thickness, columnar growth angle, and pore volume fraction on all doublet airfoil surfaces.« less

Transparent photocatalytic coatings on the surface of the tips of medical fibre-optic bundles

NASA Astrophysics Data System (ADS)

Evstropiev, S. K.; Volynkin, V. M.; Kiselev, V. M.; Dukelskii, K. V.; Evstropyev, K. S.; Demidov, V. V.; Gatchin, Yu. A.

2017-12-01

We report the results of the development of the sol - gel method for obtaining thin, transparent (in the visible part of the spectrum) TiO2/MgO coatings on the surfaces of the tips of medical fibre-optic bundles. Such coatings are capable of generating singlet oxygen under the action of UV radiation and are characterised by high antibacterial activity.

Demonstration Of A Nanomaterial-Modified Primer For Use In Corrosion-Inhibiting Coating Systems

DTIC Science & Technology

2011-11-01

abrasive blasting or other means. This report documents the materials and methodologies used for testing and application of the new coating systems on the...method with improved corrosion resistant coatings will provide the DoD with a means to cost effectively rehabilitate the outer metal surfaces of...contained with environmental controls in place. ........................................ 9 Figure 6. Abrasive blast-cleaned tank surface

METAL COATING BATHS

DOEpatents

Robinson, J.W.

1958-08-26

A method is presented for restoring the effectiveness of bronze coating baths used for hot dip coating of uranium. Such baths, containing a high proportion of copper, lose their ability to wet uranium surfaces after a period of use. The ability of such a bath to wet uranium can be restored by adding a small amount of metallic aluminum to the bath, and skimming the resultant hard alloy from the surface.

Electrically resistive coating for remediation (regeneration) of a diesel particulate filter and method

DOEpatents

Phelps, Amanda C [Malibu, CA; Kirby, Kevin K [Calabasas Hills, CA; Gregoire, Daniel J [Thousand Oaks, CA

2012-02-14

A resistively heated diesel particulate filter (DPF). The resistively heated DPF includes a DPF having an inlet surface and at least one resistive coating on the inlet surface. The at least one resistive coating is configured to substantially maintain its resistance in an operating range of the DPF. The at least one resistive coating has a first terminal and a second terminal for applying electrical power to resistively heat up the at least one resistive coating in order to increase the temperature of the DPF to a regeneration temperature. The at least one resistive coating includes metal and semiconductor constituents.

Method of producing a carbon coated ceramic membrane and associated product

DOEpatents

Liu, P.K.T.; Gallaher, G.R.; Wu, J.C.S.

1993-11-16

A method is described for producing a carbon coated ceramic membrane including passing a selected hydrocarbon vapor through a ceramic membrane and controlling ceramic membrane exposure temperature and ceramic membrane exposure time. The method produces a carbon coated ceramic membrane of reduced pore size and modified surface properties having increased chemical, thermal and hydrothermal stability over an uncoated ceramic membrane. 12 figures.

Tungsten-yttria carbide coating for conveying copper

DOEpatents

Rothman, Albert J.

1993-01-01

A method is provided for providing a carbided-tungsten-yttria coating on the interior surface of a copper vapor laser. The surface serves as a wick for the condensation of liquid copper to return the condensate to the interior of the laser for revolatilization.

Method and apparatus for laser scribing glass sheet substrate coatings

DOEpatents

Borgeson, Frank A.; Hanak, Joseph J.; Harju, Ricky S.; Helman, Norman L.; Hecht, Kenneth R.

2003-05-06

A method and apparatus (42) for laser scribing coatings on glass sheet substrates by conveying the substrate adjacent a laser source (83) that provides a pulsed laser beam (84) with a wavelength at a near-infrared fundamental frequency and having a frequency in the range of 50 to 100 kilohertz and a pulse duration in the range of 8 to 70 nanoseconds, and by reflecting the beam by an XYZ galvanometer controlled mirror system (90) toward an uncoated surface of the substrate for passage therethrough to the coating on the other surface to provide overlapping ablations through the coating and scribing at a speed of at least 1000 millimeters per second.

Method and apparatus for laser scribing glass sheet substrate coatings

DOEpatents

Borgeson, Frank A.; Hanak, Joseph J.; Harju, Ricky S.; Harju, Karen M.; Helman, Norman L.; Hecht, Kenneth R.

2005-07-19

A method and apparatus (42) for laser scribing coatings on glass sheet substrates by conveying the substrate adjacent a laser source (83) that provides a pulsed laser beam (84) with a wavelength at a near-infrared fundamental frequency and having a frequency in the range of 50 to 100 kilohertz and a pulse duration in the range of 8 to 70 nanoseconds, and by reflecting the beam by an XYZ galvanometer controlled mirror system (90) toward an uncoated surface of the substrate for passage therethrough to the coating on the other surface to provide overlapping ablations through the coating and scribing at a speed of at least 1000 millimeters per second.

Superoleophilic particles and coatings and methods of making the same

DOEpatents

Simpson, John T; D& #x27; Urso, Brian

2013-07-30

Superoleophilic particles and surfaces and methods of making the same are described. The superoleophilic particles can include porous particles having a hydrophobic coating layer deposited thereon. The coated porous particles are characterized by particle sizes ranging from at least 100 nm to about 10 .mu.m and a plurality of nanopores. Some of the nanopores provide flow through porosity. The superoleophilic particles also include oil pinned within the nanopores of the porous particles The plurality of porous particles can include (i) particles including a plurality of spaced apart nanostructured features comprising a contiguous, protrusive material, (ii) diatomaceous earth particles, or (iii) both. The surfaces can include the superoleophilic particles coupled to the surface.

Electrostatic powder spraying process for the fabrication of stable superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Gu, Guotuan; Tian, Yuping; Li, Zhantie; Lu, Dongfang

2011-03-01

Nano-sized Al2O3 particles were modified by heptadecafluorodecyl trimethoxysilane and 2,3-epoxy propoxy propyl trimethoxysilicane to make it both hydrophobic and reactive. The reactive nano-particles were mixed with polyester resin containing curing agents and electrostatic sprayed on stainless steel substrates to obtain stable superhydrophobic coatings after curing. The water contact angle (WCA) on the hybrid coating is influenced by the content of Al2O3 particles in the coating. As the Al2O3 concentration in the coating was increased from 0% to 8%, WCA increased from 68° to 165°. Surface topography of the coatings was examined using scanning electron microscopy (SEM). Nano-particles covered on the coating surface formed continuous film with greatly enhanced roughness, which was found to be responsible for the superhydrophobicity. The method is simple and cost effective and can be used for preparing self-cleaning superhydrophobic coating on large areas.

The effects of grooming on a copper ablative coating: a six year study.

PubMed

Tribou, Melissa; Swain, Geoffrey

2017-07-01

More than 90% of US Navy Ships are coated with copper ablative paint. These ships may spend long periods of time pier-side, which makes them vulnerable to fouling. Hull grooming has been proposed as a means of maintaining the coatings in an operational condition. This study investigated the effect of grooming on a copper ablative coating exposed statically for six years. Grooming was performed weekly or monthly with controls left ungroomed. The fouling community was visually assessed, dry film thickness measurements were taken to monitor coating loss, and the copper leaching rates were measured. It was found that weekly and monthly groomed surfaces reduced fouling, and the ungroomed surfaces became fully fouled. Coating loss was similar for weekly, monthly and ungroomed surfaces. The results suggest that grooming is a viable method for maintaining copper ablative coatings in a fouling-free condition without adverse increases in the total copper output.

Stable superhydrophilic coating on superhydrophobic porous media by functionalized nanoparticles

NASA Astrophysics Data System (ADS)

Khazaei, Masoud; Taghi Sadeghi, Mohammad; Sadat Hosseini, Marzieh

2018-01-01

In this study, the hydrophilicity property of TiO2 nano-coating was improved by zinc acetate-assisted sol-gel method. The stable superhydrophilic coating was fabricated on a superhydrophobic mineral rock surface. The wettability of surface before and after coating was characterized by contact angle measurements. The n-heptane and water droplet contact angle was 0° and 168° respectively, so the untreated rock was superhydrophobic. After nano-treatment, the n-heptane and water contact angle changed to 172° and 0° respectively, so the superhydrophilic coating was formed on the superhydrophobic surface. The thermal, mechanical and salinity stability of the fabricated coatings was investigated. The coatings had high thermal and salinity stability; they also had moderate mechanical stability that was evaluated by abrasion test. The morphology and composition of synthesized nanoparticles were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy and x-ray diffraction (XRD) analyses. Characterization of the coated surfaces was conducted by SEM and XRD analyses. Applications of these nano-coatings include surfaces where cleanliness is paramount such as in hospitals as well as the protection of public monuments and building facades from weathering. Novel industrial application includes wettability alteration of oil wet carbonate rock for enhanced oil recovery.

Designing Energy-Efficient Heat Exchangers--- Creating Micro-Channels on the Aluminum Fin Surface

NASA Astrophysics Data System (ADS)

Ying, Jia; Sommers, Andrew; Eid, Khalid

2010-03-01

In this research, a method for patterning micro-channels on aluminum surfaces is described for the purpose of exploiting those features to affect the surface wettability. Minimizing water retention on aluminum is important in the design of energy-efficient heat exchangers because water retention can deteriorate the performance of such devices. It increases the air-side pressure drop and can decrease the sensible heat transfer coefficient thereby increasing energy consumption and contributing to higher pollution levels in the environment. Photolithography is used to create the micro-scale channels and a hydrophobic polymer is used to reduce the surface energy of the aluminum plates. Droplets are both injected on the surface using a micro-syringe and condensed on the surface using an environmentally-controlled chamber. A ram'e-hart goniometer is used to determine the advancing and receding contact angles of water droplets on these modified surfaces, and a tilt-table assembly is used to measure the critical inclination angle for sliding. Our results show that droplets placed on these patterned surfaces not only have significantly lower critical inclination angles for sliding but are easier to remove from the surface at low air flow rates. Efforts to model the onset of droplet movement on these surfaces using a simple force balance relationship are currently underway.

Ta2O5/ Al2O3/ SiO2 - antireflective coating for non-planar optical surfaces by atomic layer deposition

NASA Astrophysics Data System (ADS)

Pfeiffer, K.; Schulz, U.; Tünnermann, A.; Szeghalmi, A.

2017-02-01

Antireflective coatings are essential to improve transmittance of optical elements. Most research and development of AR coatings has been reported on a wide variety of plane optical surfaces; however, antireflection is also necessary on nonplanar optical surfaces. Physical vapor deposition (PVD), a common method for optical coatings, often results in thickness gradients on strongly curved surfaces, leading to a failure of the desired optical function. In this work, optical thin films of tantalum pentoxide, aluminum oxide and silicon dioxide were prepared by atomic layer deposition (ALD), which is based on self-limiting surface reactions. The results demonstrate that ALD optical layers can be deposited on both vertical and horizontal substrate surfaces with uniform thicknesses and the same optical properties. A Ta2O5/Al2O3/ SiO2 multilayer AR coating (400-700 nm) was successfully applied to a curved aspheric glass lens with a diameter of 50 mm and a center thickness of 25 mm.

Control of surface topography in biomimetic calcium phosphate coatings.

PubMed

Costa, Daniel O; Allo, Bedilu A; Klassen, Robert; Hutter, Jeffrey L; Dixon, S Jeffrey; Rizkalla, Amin S

2012-02-28

The behavior of cells responsible for bone formation, osseointegration, and bone bonding in vivo are governed by both the surface chemistry and topography of scaffold matrices. Bone-like apatite coatings represent a promising method to improve the osteoconductivity and bonding of synthetic scaffold materials to mineralized tissues for regenerative procedures in orthopedics and dentistry. Polycaprolactone (PCL) films were coated with calcium phosphates (CaP) by incubation in simulated body fluid (SBF). We investigated the effect of SBF ion concentration and soaking time on the surface properties of the resulting apatite coatings. CaP coatings were examined by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR), and energy dispersive X-ray spectrometry (EDX). Young's modulus (E(s)) was determined by nanoindentation, and surface roughness was assessed by atomic force microscopy (AFM) and mechanical stylus profilometry. CaP such as carbonate-substituted apatite were deposited onto PCL films. SEM and AFM images of the apatite coatings revealed an increase in topographical complexity and surface roughness with increasing ion concentration of SBF solutions. Young's moduli (E(s)) of various CaP coatings were not significantly different, regardless of the CaP phase or surface roughness. Thus, SBF with high ion concentrations may be used to coat synthetic polymers with CaP layers of different surface topography and roughness to improve the osteoconductivity and bone-bonding ability of the scaffold. © 2012 American Chemical Society

Electrically conductive, black thermal control coatings for space craft application. II - Silicone matrix formulation

NASA Technical Reports Server (NTRS)

Hribar, V. F.; Bauer, J. L.; O'Donnell, T. P.

1986-01-01

Five black electrically conductive thermal-control coatings have been formulated and tested for application on the Galileo spacecraft. The coatings consisted of organic and inorganic systems applied on titanium and aluminum surfaces. The coatings were tested under simulated space environment conditions. Coated specimens were subjected to thermal radiation and convective and conductive heating from -196 to 538 C. Mechanical, physical, thermal, electrical, and optical characteristics, formulation, mixing, application, surface preparation of substrates, and a method of determining electrical resistance are presented for the silicone matrix formulation designated as GF-580.

Porous polymer coatings on metal microneedles for enhanced drug delivery

NASA Astrophysics Data System (ADS)

Ullah, Asad; Kim, Chul Min; Kim, Gyu Man

2018-04-01

We present a simple method to coat microneedles (MNs) uniformly with a porous polymer (PLGA) that can deliver drugs at high rates. Stainless steel (SS) MNs of high mechanical strength were coated with a thin porous polymer layer to enhance their delivery rates. Additionally, to improve the interfacial adhesion between the polymer and MNs, the MN surface was modified by plasma treatment followed by dip coating with polyethyleneimine, a polymer with repeating amine units. The average failure load (the minimum force sufficient for detaching the polymer layer from the surface of SS) recorded for the modified surface coating was 25 N, whereas it was 2.2 N for the non-modified surface. Calcein dye was successfully delivered into porcine skin to a depth of 750 µm by the porous polymer-coated MNs, demonstrating that the developed MNs can pierce skin easily without deformation of MNs; additional skin penetration tests confirmed this finding. For visual comparison, rhodamine B dye was delivered using porous-coated and non-coated MNs in gelatin gel which showed that delivery with porous-coated MNs penetrate deeper when compared with non-coated MNs. Finally, lidocaine and rhodamine B dye were delivered in phosphate-buffered saline (PBS) medium by porous polymer-coated and non-coated MNs. For rhodamine B, drug delivery with the porous-coated MNs was five times higher than that with the non-coated MNs, whereas 25 times more lidocaine was delivered by the porous-coated MNs compared with the non-coated MNs.

Temperature determination using pyrometry

DOEpatents

Breiland, William G.; Gurary, Alexander I.; Boguslavskiy, Vadim

2002-01-01

A method for determining the temperature of a surface upon which a coating is grown using optical pyrometry by correcting Kirchhoff's law for errors in the emissivity or reflectance measurements associated with the growth of the coating and subsequent changes in the surface thermal emission and heat transfer characteristics. By a calibration process that can be carried out in situ in the chamber where the coating process occurs, an error calibration parameter can be determined that allows more precise determination of the temperature of the surface using optical pyrometry systems. The calibration process needs only to be carried out when the physical characteristics of the coating chamber change.

Processing and Characterization of Nanoparticle Coatings for Quartz Crystal Microbalance Measurements

PubMed Central

Torrey, Jessica D.; Kirschling, Teresa L.; Greenlee, Lauren F.

2015-01-01

The quartz-crystal microbalance is a sensitive and versatile tool for measuring adsorption of a variety of compounds (e.g. small molecules, polymers, biomolecules, nanoparticles and cells) to surfaces. While the technique has traditionally been used for measuring adsorption to flat surfaces and thin ridged films, it can also be extended to study adsorption to nanoparticle surfaces when the nanoparticles are fixed to the crystal surface. The sensitivity and accuracy of the measurement depend on the users’ ability to reproducibly prepare a thin uniform nanoparticle coating. This study evaluated four coating techniques, including spin coating, spray coating, drop casting, and electrophoretic deposition, for two unique particle chemistries [nanoscale zero valent iron (nZVI) and titanium dioxide (TiO2)] to produce uniform and reproducible nanoparticle coatings for real-time quartz-crystal microbalance measurements. Uniform TiO2 coatings were produced from a 50 mg/mL methanol suspension via spin coating. Nanoscale zero-valent iron was best applied by spray coating a low concentration 1.0 mg/mL suspended in methanol. The application of multiple coatings, rather than an increase in the suspension concentration, was the best method to increase the mass of nanoparticles on the crystal surface while maintaining coating uniformity. An upper mass threshold was determined to be approximately 96 µg/cm2; above this mass, coatings no longer maintained their uniform rigid characteristic, and a low signal to noise ratio resulted in loss of measurable signal from crystal resonances above the fundamental. PMID:26958434

Laboratory evaluation of polychlorinated biphenyls encapsulation methods

EPA Science Inventory

Effectiveness and limitations of the encapsulation method for reducing polychlorinated biphenyls (PCBs) concentrations in indoor air and contaminated surface have been evaluated in the laboratory study. Ten coating materials such as epoxy and polyurethane coatings, latex paint, a...

The effects of surface tension on flooding in counter-current two-phase flow in an inclined tube

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

Deendarlianto; Forschungszentrum Dresden-Rossendorf e.V., Institute of Safety Research, P.O. Box 510 119, D-01314 Dresden; Ousaka, Akiharu

2010-10-15

The purpose of the present study is to investigate the effects of surface tension on flooding phenomena in counter-current two-phase flow in an inclined tube. Previous studies by other researchers have shown that surface tension has a stabilizing effect on the falling liquid film under certain conditions and a destabilizing or unclear trend under other conditions. Experimental results are reported herein for air-water systems in which a surfactant has been added to vary the liquid surface tension without altering other liquid properties. The flooding section is a tube of 16 mm in inner diameter and 1.1 m length, inclined atmore » 30-60 from horizontal. The flooding mechanisms were observed by using two high-speed video cameras and by measuring the time variation of liquid hold-up along the test tube. The results show that effects of surface tension are significant. The gas velocity needed to induce flooding is lower for a lower surface tension. There was no upward motion of the air-water interfacial waves upon flooding occurrence, even for lower a surface tension. Observations on the liquid film behavior after flooding occurred suggest that the entrainment of liquid droplets plays an important role in the upward transport of liquid. Finally, an empirical correlation for flooding velocities is proposed that includes functional dependencies on surface tension and tube inclination. (author)« less

A preliminary report on a novel electrospray technique for nanoparticle based biomedical implants coating: precision electrospraying.

PubMed

Kumbar, Sangamesh G; Bhattacharyya, Subhabrata; Sethuraman, Swaminathan; Laurencin, Cato T

2007-04-01

The compatibility and biological efficacy of biomedical implants can be enhanced by coating their surface with appropriate agents. For predictable functioning of implants in situ, it is often desirable to obtain an extremely uniform coating thickness without effects on component dimensions or functions. Conventional coating techniques require rigorous processing conditions and often have limited adhesion and composition properties. In the present study, the authors report a novel precision electrospraying technique that allows both degradable and nondegradable coatings to be placed. Thin metallic slabs, springs, and biodegradable sintered microsphere scaffolds were coated with poly(lactide-co-glycolide) (PLAGA) using this technique. The effects of process parameters such as coating material concentration and applied voltage were studied using PLAGA and poly(ethylene glycol) coatings. Morphologies of coated surfaces were qualitatively characterized by scanning electron microscopy. Qualitative observations suggested that the coatings were composed of particles of various size/shape and agglomerates with different porous architectures. PLAGA coatings of uniform thickness were observed on all surfaces. Spherical nanoparticle poly(ethylene glycol) coatings (462-930 nm) were observed at all concentrations studied. This study found that the precision electrospraying technique is elegant, rapid, and reproducible with precise control over coating thickness (mum to mm) and is a useful alternative method for surface modification of biomedical implants. (c) 2006 Wiley Periodicals, Inc.

Interface activation and surface characteristics of Ti/TiN/HA coated sintered stainless steels

NASA Astrophysics Data System (ADS)

Choe, Han-Cheol; Ko, Yeong-Mu

2006-02-01

Interface activation and surface characteristics of Ti/TiN/HA film coated sintered stainless steels (SSS) have been investigated by electrochemical and biocompatibility tests. HA (hydroxyapatite), Ti, and Ti/TiN film coatings were applied using electron-beam deposition method (EB-PVD). Ti, Ti/TiN, and Ti/TiN/HA film coated surfaces and layers were investigated by SEM and XPS. The coated films showed micro-columnar structure, and Ti/TiN/HA films were denser than Ti or HA-only film. The corrosion resistance of the HA coating was similar to that of Ti/TiN/HA film coating when Cu content reached 4 wt.%, but the corrosion resistance of the HA coating decreased when Cu content increased from 4 wt.% in 0.9% NaCl solution. Therefore, HA-only coating could ensure corrosion resistance when Cu content does not exceed 4 wt.%. The results of biocompatibility tests of SSS on dogs showed that bone formation and biocompatibility were favorable when Cu content did not exceed 4 wt.%. The biocompatibility with bone was generally favorable in Ti/TiN/HA film coating and HA-only coating, while bone formation was somewhat faster for the HA film coated surface than for the Ti/TiN/HA film coating. Also, good cell growth and osseointegration without toxicity were observed.

METHOD OF FORMING TANTALUM SILICIDE ON TANTALUM SURFACES

DOEpatents

Bowman, M.G.; Krikorian, N.H.

1961-10-01

A method is described for forming a non-corrosive silicide coating on tantalum. The coating is made through the heating of trirhenium silicides in contact with the tantalum object to approximately 1400 deg C at which temperature trirhenium silicide decomposes into rhenium and gaseous silicons. The silicon vapor reacts with the tantalum surface to form a tantalum silicide layer approximately 10 microns thick. (AEC)

Conformal dip-coating of patterned surfaces for capillary die-to-substrate self-assembly

NASA Astrophysics Data System (ADS)

Mastrangeli, M.; Ruythooren, W.; Van Hoof, C.; Celis, J.-P.

2009-04-01

Capillarity-driven self-assembly of small chips onto planar target substrates is a promising alternative to robotic pick-and-place assembly. It critically relies on the selective deposition of thin fluid films on patterned binding sites, which is anyway normally non-conformal. We found that the addition of a thin wetting sidewall, surrounding the entire site perimeter, enables the conformal fluid coverage of arbitrarily shaped sites through dip-coating, significantly improves the reproducibility of the coating process and strongly reduces its sensitivity to surface defects. In this paper we support the feasibility and potential of this method by demonstrating the conformal dip-coating of square and triangular sites conditioned with combinations of different hydrophobic and hydrophilic surface chemistries. We present both experimental and simulative evidence of the advantages brought by the introduction of the wetting boundary on film coverage accuracy. Application of our surface preparation method to capillary self-assembly could result in higher precision in die-to-substrate registration and larger freedom in site shape design.

Surface pressure measurement by oxygen quenching of luminescence

NASA Technical Reports Server (NTRS)

Gouterman, Martin P. (Inventor); Kavandi, Janet L. (Inventor); Gallery, Jean (Inventor); Callis, James B. (Inventor)

1993-01-01

Methods and compositions for measuring the pressure of an oxygen-containing gas on an aerodynamic surface, by oxygen-quenching of luminescence of molecular sensors is disclosed. Objects are coated with luminescent films containing a first sensor and at least one of two additional sensors, each of the sensors having luminescences that have different dependencies on temperature and oxygen pressure. Methods and compositions are also provided for improving pressure measurements (qualitative or quantitive) on surfaces coated with a film having one or more types of sensor.

Surface pressure measurement by oxygen quenching of luminescence

NASA Technical Reports Server (NTRS)

Gouterman, Martin P. (Inventor); Kavandi, Janet L. (Inventor); Gallery, Jean (Inventor); Callis, James B. (Inventor)

1994-01-01

Methods and compositions for measuring the pressure of an oxygen-containing gas on an aerodynamic surface, by oxygen-quenching of luminescence of molecular sensors is disclosed. Objects are coated with luminescent films containing a first sensor and at least one of two additional sensors, each of the sensors having luminescences that have different dependencies on temperature and oxygen pressure. Methods and compositions are also provided for improving pressure measurements (qualitative or quantitive) on surfaces coated with a film having one or more types of sensor.

Fabrication of Water Jet Resistant and Thermally Stable Superhydrophobic Surfaces by Spray Coating of Candle Soot Dispersion.

PubMed

Qahtan, Talal F; Gondal, Mohammed A; Alade, Ibrahim O; Dastageer, Mohammed A

2017-08-08

A facile synthesis method for highly stable carbon nanoparticle (CNP) dispersion in acetone by incomplete combustion of paraffin candle flame is presented. The synthesized CNP dispersion is the mixture of graphitic and amorphous carbon nanoparticles of the size range of 20-50 nm and manifested the mesoporosity with an average pore size of 7 nm and a BET surface area of 366 m 2 g -1 . As an application of this material, the carbon nanoparticle dispersion was spray coated (spray-based coating) on a glass surface to fabricate superhydrophobic (water contact angle > 150° and sliding angle < 10 °) surfaces. The spray coated surfaces were found to exhibit much improved water jet resistance and thermal stability up to 400 °C compared to the surfaces fabricated from direct candle flame soot deposition (candle-based coating). This study proved that water jet resistant and thermally stable superhydrophobic surfaces can be easily fabricated by simple spray coating of CNP dispersion gathered from incomplete combustion of paraffin candle flame and this technique can be used for different applications with the potential for the large scale fabrication.

Pulse electrodeposition of self-lubricating Ni-W/PTFE nanocomposite coatings on mild steel surface

NASA Astrophysics Data System (ADS)

Sangeetha, S.; Kalaignan, G. Paruthimal; Anthuvan, J. Tennis

2015-12-01

Ni-W/PTFE nanocomposite coatings with various contents of PTFE (polytetafluoroethylene) particles were prepared by pulse current (PC) electrodeposition from the Ni-W plating bath containing self lubricant PTFE particles to be co-deposited. Co-deposited PTFE particulates were uniformly distributed in the Ni-W alloy matrix. The coatings were characterized by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDAX), X-ray Diffractometry (XRD) and Vicker's micro hardness tester. Tafel Polarization and electrochemical Impedance methods were used to evaluate the corrosion resistance behaviour of the nanocomposite coatings in 3.5% NaCl solution. It was found that, the Ni-W/PTFE nanocomposite coating has better corrosion resistance than the Ni-W alloy coating. Surface roughness and friction coefficient of the coated samples were assessed by Mitutoyo Surftest SJ-310 (ISO1997) and Scratch tester TR-101-M4 respectively. The contact angle (CA) of a water droplet on the surface of nanocomposite coating was measured by Optical Contact Goniometry (OCA 35). These results indicated that, the addition of PTFE in the Ni-W alloy matrix has resulted moderate microhardness, smooth surface, less friction coefficient, excellent water repellency and enhanced corrosion resistance of the nanocomposite coatings.

Gravity settling

DOEpatents

Davis, Hyman R.; Long, R. H.; Simone, A. A.

1979-01-01

Solids are separated from a liquid in a gravity settler provided with inclined solid intercepting surfaces to intercept the solid settling path to coalesce the solids and increase the settling rate. The intercepting surfaces are inverted V-shaped plates, each formed from first and second downwardly inclined upwardly curved intersecting conical sections having their apices at the vessel wall.

Method of protecting surfaces from abrasion and abrasion resistant articles of manufacture

DOEpatents

Hirschfeld, T.B.

1988-06-09

Surfaces of fabricated structures are protected from damage by impacting particulates by a coating of hard material formed as a mass of thin flexible filaments having root ends secured to the surface and free portions which can flex and overlap to form a resilient cushioning mat which resembles hair or fur. The filamentary coating covers the underlying surface with hard abrasion resistance material while also being compliant and capable of local accommodation to particle impacts. The coating can also function as thermal and/or acoustical insulation and has a friction reducing effect. 11 figs.

Enhanced protective properties of epoxy/polyaniline-camphorsulfonate nanocomposite coating on an ultrafine-grained metallic surface

NASA Astrophysics Data System (ADS)

Pour-Ali, Sadegh; Kiani-Rashid, Alireza; Babakhani, Abolfazl; Davoodi, Ali

2016-07-01

An ultrafine-grained surface layer on mild steel substrate with average grain size of 77 nm was produced through wire brushing process. Surface grain size was determined through transmission electron microscopy and X-ray diffraction methods. This substrate was coated with epoxy and an in situ synthesized epoxy/polyaniline-camphorsulfonate (epoxy/PANI-CSA) nanocomposite. The corrosion behavior was studied by open circuit potential, potentiodynamic polarization and impedance measurements. Results of electrochemical tests evidenced the enhanced protective properties of epoxy/PANI-CSA coating on the substrate with ultrafine-grained surface.

Numerical investigation of sliding drops on an inclined surface

NASA Astrophysics Data System (ADS)

Legendre, Dominique; Pedrono, Annaig; Interface Group Team

2017-11-01

Despite it apparent simplicity, the behavior of a drop on an inclined solid surface is far to be properly reproduced by numerical simulation. It involves static, hysteresis and dynamic contact line behaviors. Depending on the fluid properties, the hysteresis and the wall inclination, different drop shapes (rounded, corner or pearling drop) can be observed. The 3D numerical simulations of sliding droplets presented in this work are based on a Volume of Fluid (VoF) solver without any interface reconstruction developed in the JADIM code. The surface tension is solved using the classical CSF (Continuum Surface Force) model and a sub grid model is used to describe under hysteresis conditions both the shape, the dissipation of the non resolved scales of a moving contact line. Numerical simulations are compared with the experiments of. The agreement with experiments is found to be very good for both he critical angle of inclination for siding as well as for the specific shapes: rounded, corner and pearling drops. The simulations have been used to extend the range of hysteresis covered by the experiments.

Semiconductor with protective surface coating and method of manufacture thereof. [Patent application

DOEpatents

Hansen, W.L.; Haller, E.E.

1980-09-19

Passivation of predominantly crystalline semiconductor devices is provided for by a surface coating of sputtered hydrogenated amorphous semiconductor material. Passivation of a radiation detector germanium diode, for example, is realized by sputtering a coating of amorphous germanium onto the etched and quenched diode surface in a low pressure atmosphere of hydrogen and argon. Unlike prior germanium diode semiconductor devices, which must be maintained in vacuum at cryogenic temperatures to avoid deterioration, a diode processed in the described manner may be stored in air at room temperature or otherwise exposed to a variety of environmental conditions. The coating compensates for pre-existing undesirable surface states as well as protecting the semiconductor device against future impregnation with impurities.

The effect of processing on the surface physical stability of amorphous solid dispersions.

PubMed

Yang, Ziyi; Nollenberger, Kathrin; Albers, Jessica; Moffat, Jonathan; Craig, Duncan; Qi, Sheng

2014-11-01

The focus of this study was to investigate the effect of processing on the surface crystallization of amorphous molecular dispersions and gain insight into the mechanisms underpinning this effect. The model systems, amorphous molecular dispersions of felodipine-EUDRAGIT® E PO, were processed both using spin coating (an ultra-fast solvent evaporation based method) and hot melt extrusion (HME) (a melting based method). Amorphous solid dispersions with drug loadings of 10-90% (w/w) were obtained by both processing methods. Samples were stored under 75% RH/room temperatures for up to 10months. Surface crystallization was observed shortly after preparation for the HME samples with high drug loadings (50-90%). Surface crystallization was characterized by powder X-ray diffraction (PXRD), ATR-FTIR spectroscopy and imaging techniques (SEM, AFM and localized thermal analysis). Spin coated molecular dispersions showed significantly higher surface physical stability than hot melt extruded samples. For both systems, the progress of the surface crystal growth followed zero order kinetics on aging. Drug enrichment at the surfaces of HME samples on aging was observed, which may contribute to surface crystallization of amorphous molecular dispersions. In conclusion it was found the amorphous molecular dispersions prepared by spin coating had a significantly higher surface physical stability than the corresponding HME samples, which may be attributed to the increased process-related apparent drug-polymer solubility and reduced molecular mobility due to the quenching effect caused by the rapid solvent evaporation in spin coating. Copyright © 2014 Elsevier B.V. All rights reserved.

Method of processing materials using an inductively coupled plasma

DOEpatents

Hull, Donald E.; Bieniewski, Thomas M.

1989-01-01

A method for coating surfaces or implanting ions in an object using an inductively coupled plasma. The method provides a gas-free environment, since the plasma is formed without using a gas. The coating material or implantation material is intitially in solid form.

Fabrication of a superhydrophobic and high-glossy copper coating on aluminum substrates

NASA Astrophysics Data System (ADS)

Yang, Hao; He, Yuantao; Wu, Zhongqiang; Miao, Jing; Yang, Fang; Lu, Zhong

2018-03-01

Superhydrophobic metal coatings have been extensively studied in recent years because of their significant potential applications. Unfortunately, most of them lost the original metallic luster due to the micro/nano binary structures. In this paper, a facile method was developed to prepare a superhydrophobic and high-glossy copper coating on aluminum substrates. The bionic lotus leaf surfaces were constructed by electroless plating method and further modified with octadecanethiol. The wettability and gloss could be tuned by the concentration of the precursor. With the increase of CuSO4 concentration, the surface roughness of the coating raised, thus resulting in increase of contact angle and decrease of glossiness. When the CuSO4 concentration was 30 mmol/L, the coating exhibited a sub-micro/nano binary structure, in which 20-30 nm protuberances were grown on 300-500 nm mastoids. Such special morphology endowed the coating with superhydrophobic and high-glossy properties, and the coating also showed ultra-low water adhesion and stable dynamic water repellence.

Enhancement of anticorrosion property of 304 stainless steel using silane coatings

NASA Astrophysics Data System (ADS)

Akhtar, Sultan; Matin, Asif; Madhan Kumar, A.; Ibrahim, Ahmed; Laoui, Tahar

2018-05-01

In the present work, silane coatings based on glycidoxypropyltrimethoxysilane/methyltrimethoxysilane (GPTMS/MTMS) and silica nanoparticles were prepared by a sol-gel method. A simple dip-coating method was applied for film deposition and the effect of immersion time and number of immersion cycles on corrosion behavior of 304 stainless steel (SS) was investigated. Scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS) was used to study the surface morphology and elemental composition of the modified surfaces. The corrosion behavior of the coated and uncoated SS substrates was studied by potentiodynamic polarization and electrochemical impedance spectroscopy in 0.6 M sodium chloride solution. Our results showed that the presence of coatings improved the anti-corrosion property of SS substrates. The coating with a dipping time of 10 min and 3 dipping cycles exhibited the best protection efficiency compared to other coatings and the uncoated substrate. SEM/EDS findings and contact angle measurements supported the conclusions drawn from the corrosion study.

40 CFR 60.496 - Test methods and procedures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Surface Coating Industry § 60.496 Test methods and procedures. (a) The reference methods in appendix A to...) Method 4 for stack gas moisture. (b) For Method 24, the coating sample must be a 1-litre sample collected... volume must be 0.003 dscm except that shorter sampling times or smaller volumes, when necessitated by...

40 CFR 60.496 - Test methods and procedures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Surface Coating Industry § 60.496 Test methods and procedures. (a) The reference methods in appendix A to...) Method 4 for stack gas moisture. (b) For Method 24, the coating sample must be a 1-litre sample collected... volume must be 0.003 dscm except that shorter sampling times or smaller volumes, when necessitated by...

40 CFR 60.496 - Test methods and procedures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Surface Coating Industry § 60.496 Test methods and procedures. (a) The reference methods in appendix A to...) Method 4 for stack gas moisture. (b) For Method 24, the coating sample must be a 1-litre sample collected... volume must be 0.003 dscm except that shorter sampling times or smaller volumes, when necessitated by...

40 CFR 60.496 - Test methods and procedures.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Surface Coating Industry § 60.496 Test methods and procedures. (a) The reference methods in appendix A to...) Method 4 for stack gas moisture. (b) For Method 24, the coating sample must be a 1-litre sample collected... volume must be 0.003 dscm except that shorter sampling times or smaller volumes, when necessitated by...

40 CFR 60.496 - Test methods and procedures.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Surface Coating Industry § 60.496 Test methods and procedures. (a) The reference methods in appendix A to...) Method 4 for stack gas moisture. (b) For Method 24, the coating sample must be a 1-litre sample collected... volume must be 0.003 dscm except that shorter sampling times or smaller volumes, when necessitated by...

Self-Cleaning Ceramic Tiles Produced via Stable Coating of TiO₂ Nanoparticles.

PubMed

Shakeri, Amid; Yip, Darren; Badv, Maryam; Imani, Sara M; Sanjari, Mehdi; Didar, Tohid F

2018-06-13

The high photocatalytic power of TiO₂ nanoparticles has drawn great attention in environmental and medical applications. Coating surfaces with these particles enables us to benefit from self-cleaning properties and decomposition of pollutants. In this paper, two strategies have been introduced to coat ceramic tiles with TiO₂ nanoparticles, and the self-cleaning effect of the surfaces on degradation of an organic dye under ultraviolent (UV) exposure is investigated. In the first approach, a simple one-step heat treatment method is introduced for coating, and different parameters of the heat treatment process are examined. In the second method, TiO₂ nanoparticles are first aminosilanized using (3-Aminopropyl)triethoxysilane (APTES) treatment followed by their covalently attachment onto CO₂ plasma treated ceramic tiles via N -(3-Dimethylaminopropyl)- N ′-ethylcarbodiimide hydrochloride (EDC) and N -Hydroxysuccinimide (NHS) chemistry. We monitor TiO₂ nanoparticle sizes throughout the coating process using dynamic light scattering (DLS) and characterize developed surfaces using X-ray photoelectron spectroscopy (XPS). Moreover, hydrophilicity of the coated surfaces is quantified using a contact angle measurement. It is shown that applying a one-step heat treatment process with the optimum temperature of 200 °C for 5 h results in successful coating of nanoparticles and rapid degradation of dye in a short time. In the second strategy, the APTES treatment creates a stable covalent coating, while the photocatalytic capability of the particles is preserved. The results show that coated ceramic tiles are capable of fully degrading the added dyes under UV exposure in less than 24 h.

Influence of Cu, Au and Ag on structural and surface properties of bioactive coatings based on titanium.

PubMed

Wojcieszak, D; Mazur, M; Kalisz, M; Grobelny, M

2017-02-01

In this work influence of copper, silver and gold additives on structural and surface properties of biologically active thin films based on titanium have been described. Coatings were prepared by magnetron sputtering method. During each process metallic discs (targets) - Ti and the additive (Cu, Ag or Au) were co-sputtered in argon atmosphere. Structural investigation of as-deposited coatings was performed with the aid of XRD and SEM/EDS method. It was found that all prepared thin films were homogenous. Addition of Cu, Ag and Au resulted in nanocrystalline structure. Moreover, influence of these additives on hardness and antibacterial activity of titanium coatings was also studied. Ti-Cu, Ti-Ag and Ti-Au films had lower hardness as-compared to Ti. According to AAS results the difference of their activity was related to the ion migration process. It was found that Ti-Ag and Ti-Au coatings had biocidal effect related to direct contact of their surface with microorganisms. In the case of Ti-Cu antimicrobial activity had direct and indirect nature due to efficient ion migration process from the film surface to the surrounding environment. Functional features of coatings such as wettability and corrosion resistance were also examined and included in the comprehensive analysis. Copyright © 2016 Elsevier B.V. All rights reserved.

Surface transformation by a “cocktail” solvent enables stable cathode materials for sodium ion batteries

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

Mu, Linqin; Rahman, Muhammad Mominur; Zhang, Yan

Coating the surfaces of active materials has become an effective and indispensable path towards the stable operation of practical rechargeable batteries. Improving the affordability of coating processes can bring enormous manufacturing advantages to battery applications. Here in this paper, we report a cheap, simple and efficient method to create conformal coating layers on the primary particles of sodium layered oxide materials for improving battery performance. Mimicking the cathode–electrolyte interfacial reaction in practical cells, we create conformal coating layers via the spontaneous reaction between the oxidative cathode surfaces and a cocktail of reductive organic solvents. The conformal coating layers consist ofmore » metal–organic compounds with reduced transition metal cations, i.e., artificial cathode–electrolyte interphases (CEIs). The cells containing these coated cathode materials deliver much improved cycle life while maintaining reasonably high reversible capacity and rate capability. Furthermore, the structural stability and water resistance are enhanced, which can practically help simplify the storage protocol of cathode powders prior to battery manufacturing. The surfaces of most oxide cathode materials (e.g., lithium cathodes and sodium cathodes) are highly oxidative, and thus we expect that the present method, with tailored experimental parameters, can be readily applied to most battery systems.« less

Surface transformation by a “cocktail” solvent enables stable cathode materials for sodium ion batteries

DOE PAGES

Mu, Linqin; Rahman, Muhammad Mominur; Zhang, Yan; ...

2018-01-09

Coating the surfaces of active materials has become an effective and indispensable path towards the stable operation of practical rechargeable batteries. Improving the affordability of coating processes can bring enormous manufacturing advantages to battery applications. Here in this paper, we report a cheap, simple and efficient method to create conformal coating layers on the primary particles of sodium layered oxide materials for improving battery performance. Mimicking the cathode–electrolyte interfacial reaction in practical cells, we create conformal coating layers via the spontaneous reaction between the oxidative cathode surfaces and a cocktail of reductive organic solvents. The conformal coating layers consist ofmore » metal–organic compounds with reduced transition metal cations, i.e., artificial cathode–electrolyte interphases (CEIs). The cells containing these coated cathode materials deliver much improved cycle life while maintaining reasonably high reversible capacity and rate capability. Furthermore, the structural stability and water resistance are enhanced, which can practically help simplify the storage protocol of cathode powders prior to battery manufacturing. The surfaces of most oxide cathode materials (e.g., lithium cathodes and sodium cathodes) are highly oxidative, and thus we expect that the present method, with tailored experimental parameters, can be readily applied to most battery systems.« less

Calcium phosphate-based coatings on titanium and its alloys.

PubMed

Narayanan, R; Seshadri, S K; Kwon, T Y; Kim, K H

2008-04-01

Use of titanium as biomaterial is possible because of its very favorable biocompatibility with living tissue. Titanium implants having calcium phosphate coatings on their surface show good fixation to the bone. This review covers briefly the requirements of typical biomaterials and narrowly focuses on the works on titanium. Calcium phosphate ceramics for use in implants are introduced and various methods of producing calcium phosphate coating on titanium substrates are elaborated. Advantages and disadvantages of each type of coating from the view point of process simplicity, cost-effectiveness, stability of the coatings, coating integration with the bone, cell behavior, and so forth are highlighted. Taking into account all these factors, the efficient method(s) of producing these coatings are indicated finally.

Effect of sealer coating and storage methods on the surface roughness of soft liners.

PubMed

Usta Kutlu, Ilknur; Yanikoğlu, Nuran Dinckal; Kul, Esra; Duymuş, Zeynep Yesïl; Sağsöz, Nurdan Polat

2016-03-01

A soft lining is applied under a removable prosthesis for various reasons. The porosity of the lining material may increase colonization by microorganisms and cause tissue inflammation. The purpose of this in vitro study was to evaluate the effect of sealer coating on the surface roughness of soft lining materials under 4 different conditions. A total of 125 specimens were prepared. One high-temperature silicone-based soft lining material and 2 room-temperature-polymerized soft lining materials (1 silicone-based and 1 methacrylate-based) were used. Twenty-five specimens of each room-temperature soft lining material were coated with 2 layers of surface sealer. Additionally, 5 specimens of each material were stored in either distilled water, Coca-Cola, denture cleanser, saliva, or air. The surface roughness was measured at baseline and after 1, 7, 14, and 28 days. Surface roughness values were analyzed with repeated measures analysis of variance, and the Bonferroni multiple comparison test was performed using time-dependent groups and storage methods. In the time-dependent groups, methacrylate-based sealer-coated soft liners exhibited a significant increase in roughness (1.74-2.09 μm, P<.001), and silicone-based sealer-coated soft liners exhibited a decrease in roughness, but it was not significant (2.16-2.02 μm, P>.05). Therefore, the sealer coating was not effective in reducing surface roughness. Among the time-dependent storage methods, the denture cleanser exhibited an almost significant increase in roughness (1.83-1.99 μm, P=.054). Coca-Cola and artificial saliva did not show a significant difference (P>.05). However, a significant decrease in roughness was found with distilled water (P=.02) and air (P<.001). Statistically significant differences in surface roughness were found among the different types of soft liners. The sealer coating had no significant effect, and denture cleanser slightly increased the surface roughness. Contrary to expectations, the roughness did not increase in all groups over time. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

The impact of nano-coating on surface charge accumulation of epoxy resin insulator: characteristic and mechanism

NASA Astrophysics Data System (ADS)

Qi, Bo; Gao, Chunjia; Lv, Yuzhen; Li, Chengrong; Tu, Youping; Xiong, Jun

2018-06-01

The flashover phenomenon of the insulator is the main cause for insulating failure of GIS/GIL, and one of the most critical impacting factors is the accumulation of surface charge. The common methods to restrain the surface charge accumulation are reviewed in this paper. Through the reasonable comparison and analysis of these methods, nano-coatings for the insulator were selected as a way to restrain the surface charge accumulation. Based on this, six nano-coated epoxy resin samples with different concentrations of P25-TiO2 nanoparticles were produced. A high precision 3D surface charge measurement system was developed in this paper with a spatial resolution of 4.0 mm2 and a charge resolution of 0.01 µC (m2 · mV)‑1. The experimental results for the epoxy resin sample showed that with the concentration of nanoparticles of the coating material increasing, the surface charge density tended to first decrease and then increase. In the sample coated with 0.5% concentration of nanoparticles, the suppression effect is the optimum, leading to a 63.8% reduction of charge density under DC voltage. The application test for actual nano-coated GIS/GIL basin insulator indicated that the maximum suppression degree for the charge density under DC voltage could reach 48.3%, while it could reach 22.2% for switching impulse voltage and 12.5% for AC context. The control mechanism of nano-coatings on charge accumulation was proposed based on the analysis for surface morphology features and traps characteristics; the shallow traps dominate in the migration of charges while the deep traps operate on the charge accumulation. With the concentration of nanoparticles in nano-coating material mounting up, the density of shallow traps continuously increases, while for deep traps, it first decreases and then increases. For the sample with 0.5% concentration of nanoparticles coated, the competition between shallow traps and deep traps comes to the most balanced state, producing the most significant suppression impact on surface charge accumulation.

Superhydrophilicity and antibacterial property of a Cu-dotted oxide coating surface

PubMed Central

2010-01-01

Background Aluminum-made settings are widely used in healthcare, schools, public facilities and transit systems. Frequently-touched surfaces of those settings are likely to harbour bacteria and be a potential source of infection. One method to utilize the effectiveness of copper (Cu) in eliminating pathogens for these surfaces would be to coat the aluminum (Al) items with a Cu coating. However, such a combination of Cu and Al metals is susceptible to galvanic corrosion because of their different electrochemical potentials. Methods In this work, a new approach was proposed in which electrolytic plasma oxidation (EPO) of Al was used to form an oxide surface layer followed by electroplating of Cu metal on the top of the oxide layer. The oxide was designed to function as a corrosion protective and biocompatible layer, and the Cu in the form of dots was utilized as an antibacterial material. The antibacterial property enhanced by superhydrophilicity of the Cu-dotted oxide coating was evaluated. Results A superhydrophilic surface was successfully prepared using electrolytic plasma oxidation of aluminum (Al) followed by electroplating of copper (Cu) in a Cu-dotted form. Both Cu plate and Cu-dotted oxide surfaces had excellent antimicrobial activities against E. coli ATCC 25922, methicillin-resistant Staphylococcus aureus (MRSA) ATCC 43300 and vancomycin-resistant Enterococcus faecium (VRE) ATCC 51299. However, its Cu-dotted surface morphology allowed the Cu-dotted oxide surface to be more antibacterial than the smooth Cu plate surface. The enhanced antibacterial property was attributed to the superhydrophilic behaviour of the Cu-dotted oxide surface that allowed the bacteria to have a more effective killing contact with Cu due to spreading of the bacterial suspension media. Conclusion The superhydrophilic Cu-dotted oxide coating surface provided an effective method of controlling bacterial growth and survival on contact surfaces and thus reduces the risk of infection and spread of bacteria-related diseases particularly in moist or wet environments. PMID:20843373

Influence of Deposition Conditions on Fatigue Properties of Martensitic Stainless Steel with Tin Film Coated by Arc Ion Plating Method

NASA Astrophysics Data System (ADS)

Fukui, Satoshi; Yonekura, Daisuke; Murakami, Ri-Ichi

The surface properties like roughness etc. strongly influence the fatigue strength of high-tensile steel. To investigate the effect of surface condition and TiN coating on the fatigue strength of high-strength steel, four-point bending fatigue tests were carried out for martensitic stainless steel with TiN film coated using arc ion plating (AIP) method. This study, using samples that had been polished under several size of grind particle, examines the influence of pre-coating treatment on fatigue properties. A 2-µm-thick TiN film was deposited onto the substrate under three kinds of polishing condition. The difference of the hardness originated in the residual stress or thin deformation layer where the difference of the size of grinding particle of the surface polishing. And it leads the transformation of the interface of the substrate and the TiN film and improves fatigue limit.

MAPs/bFGF-PLGA microsphere composite-coated titanium surfaces promote increased adhesion and proliferation of fibroblasts.

PubMed

Wang, Zhongshan; Wu, Guofeng; Bai, Shizhu; Feng, Zhihong; Dong, Yan; Zhou, Jian; Qin, Haiyan; Zhao, Yimin

2014-06-01

Infection and epithelial downgrowth are two major problems with maxillofacial transcutaneous implants, and both are mainly due to lack of stable closure of soft tissues at transcutaneous sites. Fibroblasts have been shown to play a key role in the formation of biological seals. In this work, titanium (Ti) model surfaces were coated with mussel adhesive proteins (MAPs) utilizing its unique adhesion ability on diverse inorganic and organic surfaces in wet environments. Prepared basic fibroblast growth factor (bFGF)-poly(lactic-co-glycolic acid) (PLGA) microspheres can be easily synthesized and combined onto MAPs-coated Ti surfaces, due to the negative surface charges of microspheres in aqueous solution, which is in contrast to the positive charges of MAPs. Titanium model surfaces were divided into three groups. Group A: MAPs/bFGF-PLGA microspheres composite-coated Ti surfaces. Group B: MAPs-coated Ti surfaces. Group C: uncoated Ti surfaces. The effects of coated Ti surfaces on adhesion of fibroblasts, cytoskeletal organization, proliferation, and extracellular matrix (ECM)-related gene expressions were examined. The results revealed increased adhesion (P < 0.05), enhanced actin cytoskeletal organization, and up-regulated ECM-related gene expressions in groups A and B compared with group C. Increased proliferation of fibroblasts during five days of incubation was observed in group A compared with groups B and C (P < 0.05). Collectively, the results from this in vitro study demonstrated that MAPs/bFGF-PLGA microspheres composite-coated Ti surfaces had the ability to increase fibroblast functionality. In addition, MAPs/bFGF-PLGA microsphere composite-coated Ti surfaces should be studied further as a method of promoting formation of stable biological seals around transcutaneous sites.

On the Astrid asteroid family

NASA Astrophysics Data System (ADS)

Carruba, V.

2016-09-01

Among asteroid families, the Astrid family is peculiar because of its unusual inclination distribution. Objects at a ≃ 2.764 au are quite dispersed in this orbital element, giving the family a `crab-like' appearance. Recent works showed that this feature is caused by the interaction of the family with the s - sC nodal secular resonance with Ceres, that spreads the inclination of asteroids near its separatrix. As a consequence, the currently observed distribution of the vW component of terminal ejection velocities obtained from inverting Gauss equation is quite leptokurtic, since this parameter mostly depends on the asteroids inclination. The peculiar orbital configuration of the Astrid family can be used to set constraints on key parameters describing the strength of the Yarkovsky force, such as the bulk and surface density and the thermal conductivity of surface material. By simulating various fictitious families with different values of these parameters, and by demanding that the current value of the kurtosis of the distribution in vW be reached over the estimated lifetime of the family, we obtained that the thermal conductivity of Astrid family members should be ≃0.001 W m-1 K-1, and that the surface and bulk density should be higher than 1000 kg m-3. Monte Carlo methods simulating Yarkovsky and stochastic Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) evolution of the Astrid family show its age to be T = 140 ± 30 Myr old, in good agreement with estimates from other groups. Its terminal ejection velocity parameter is in the range V_{EJ}= 5^{+17}_{-5} m s-1. Values of VEJ larger than 25 m s-1 are excluded from constraints from the current inclination distribution.

Method for depositing a uniform layer of particulate material on the surface of an article having interconnected porosity

DOEpatents

Wrenn, Jr., George E.; Lewis, Jr., John

1984-01-01

The invention is a method for depositing liquid-suspended particles on an immersed porous article characterized by interconnected porosity. In one form of the invention, coating is conducted in a vessel containing an organic liquid supporting a colloidal dispersion of graphite sized to lodge in surface pores of the article. The liquid comprises a first volatile component (e.g., acetone) and a second less-volatile component (e.g., toluene) containing a dissolved organic graphite-bonding agent. The liquid also contains an organic agent (e.g., cellulose gum) for maintaining the particles in suspension. A porous carbon article to be coated is immersed in the liquid so that it is permeated therewith. While the liquid is stirred to maintain a uniform blend, the vessel headspace is evacuated to effect flashing-off of the first component from the interior of the article. This causes particle-laden liquid exterior of the article to flow inwardly through its surface pores, lodging particles in these pores and forming a continuous graphite coating. The coated article is retrieved and heated to resin-bond the graphite. The method can be used to form a smooth, adherent, continuous coating of various materials on various porous articles. The method is rapid and reproducible.

Method for depositing a uniform layer of particulate material on the surface of an article having interconnected porosity

DOEpatents

Wrenn, G.E. Jr.; Lewis, J. Jr.

1982-09-29

The invention is a method for depositing liquid-suspended particles on an immersed porous article characterized by interconnected porosity. In one form of the invention, coating is conducted in a vessel containing an organic liquid supporting a colloidal dispersion of graphite sized to lodge in surface pores of the article. The liquid comprises a first volatile component (e.g., acetone) and a second less-volatile component (e.g., toluene) containing a dissolved organic graphite-bonding agent. The liquid also contains an organic agent (e.g., cellulose gum) for maintaining the particles in suspension. A porous carbon article to be coated is immersed in the liquid so that it is permeated therewith. While the liquid is stirred to maintain a uniform blend, the vessel headspace is evacuated to effect flashing-off of the first component from the interior of the article. This causes particle-laden liquid exterior of the article to flow inwardly through its surface pores, lodging particles in these pores and forming a continuous graphite coating. The coated article is retrieved and heated to resin-bond the graphite. The method can be used to form a smooth, adherent, continuous coating of various materials on various porous articles. The method is rapid and reproducible.

Surface Enhancement For Optical Plastics

NASA Astrophysics Data System (ADS)

Masso, Jon D.

1988-07-01

Optical plastics can be molded or cast to replicate traditional spherical and aspheric lenses. It is possible to obtain good optical quality, but often it is necessary or desirable to enhance the surface characteristics in a variety of ways. These include improving the abrasion resistance, chemical resistance, the addition of anti-fog, or anti-static characteristics, applying electrically conductive coatings, and applying coatings or selective absorbers for light and color control. Coatings may be entirely organic or organo-silanes applied by dipping or spinning. All dielectric coatings such as quartz abrasion resistant coatings or multilayer dielectric coatings for reflection reduction or enhancement may be applied by vacuum vapor deposition. This paper discusses a number of these coatings and surface treatments. The paper describes their characteristics and includes discussions of their durability and environmental stability. The adhesion of coatings to plastic substrate depends on the specific substrate and coating materials. Pretreatments or primers are used to promote good coating adhesion. A coating used for one purpose will generally affect other properties of the plastic and trade-offs are sometimes required. A description is given of several test methods which have been found useful in evaluating the quality of the various coatings.

Fluorine-containing composition for forming anti-reflection film on resist surface and pattern formation method

DOEpatents

Nishi, Mineo; Makishima, Hideo

1996-01-01

A composition for forming anti-reflection film on resist surface which comprises an aqueous solution of a water soluble fluorine compound, and a pattern formation method which comprises the steps of coating a photoresist composition on a substrate; coating the above-mentioned composition for forming anti-reflection film; exposing the coated film to form a specific pattern; and developing the photoresist, are provided. Since the composition for forming anti-reflection film can be coated on the photoresist in the form of an aqueous solution, not only the anti-reflection film can be formed easily, but also, the film can be removed easily by rinsing with water or alkali development. Therefore, by the pattern formation method according to the present invention, it is possible to form a pattern easily with a high dimensional accuracy.

Method of making an electrode

DOEpatents

Isenberg, Arnold O.

1986-01-01

Disclosed is a method of coating an electrode on a solid oxygen conductive oxide layer. A coating of particles of an electronic conductor is formed on one surface of the oxide layer and a source of oxygen is applied to the opposite surface of the oxide layer. A metal halide vapor is applied over the electronic conductor and the oxide layer is heated to a temperature sufficient to induce oxygen to diffuse through the oxide layer and react with the metal halide vapor. This results in the growing of a metal oxide coating on the particles of electronic conductor, thereby binding them to the oxide layer.

Antimicrobial-Coated Granules for Disinfecting Water

NASA Technical Reports Server (NTRS)

Akse, James R.; Holtsnider, John T.; Kliestik, Helen

2011-01-01

Methods of preparing antimicrobialcoated granules for disinfecting flowing potable water have been developed. Like the methods reported in the immediately preceding article, these methods involve chemical preparation of substrate surfaces (in this case, the surfaces of granules) to enable attachment of antimicrobial molecules to the surfaces via covalent bonds. A variety of granular materials have been coated with a variety of antimicrobial agents that include antibiotics, bacteriocins, enzymes, bactericides, and fungicides. When employed in packed beds in flowing water, these antimicrobial-coated granules have been proven effective against gram-positive bacteria, gram-negative bacteria, fungi, and viruses. Composite beds, consisting of multiple layers containing different granular antimicrobial media, have proven particularly effective against a broad spectrum of microorganisms. These media have also proven effective in enhancing or potentiating the biocidal effects of in-line iodinated resins and of very low levels of dissolved elemental iodine.

Surface functionalization of dopamine coated iron oxide nanoparticles for various surface functionalities

NASA Astrophysics Data System (ADS)

Sherwood, Jennifer; Xu, Yaolin; Lovas, Kira; Qin, Ying; Bao, Yuping

2017-04-01

We present effective conjugation of four small molecules (glutathione, cysteine, lysine, and Tris(hydroxymethyl)aminomethane) onto dopamine-coated iron oxide nanoparticles. Conjugation of these molecules could improve the surface functionality of nanoparticles for more neutral surface charge at physiological pH and potentially reduce non-specific adsorption of proteins to nanoparticles surfaces. The success of conjugation was evaluated with dynamic light scattering by measuring the surface charge changes and Fourier transform infrared spectroscopy for surface chemistry analysis. The stability of dopamine-coated nanoparticles and the ability of conjugated nanoparticles to reduce the formation of protein corona were evaluated by measuring the size and charge of the nanoparticles in biological medium. This facile conjugation method opens up possibilities for attaching various surface functionalities onto iron oxide nanoparticle surfaces for biomedical applications.

Raising the shields: PCR in the presence of metallic surfaces protected by tailor-made coatings.

PubMed

Scherag, Frank D; Brandstetter, Thomas; Rühe, Jürgen

2014-10-01

The implementation of PCR reactions in the presence of metallic surfaces is interesting for the generation of novel bioanalytical devices, because metals exhibit high mechanical stability, good thermal conductivity, and flexibility during deformation. However, metallic substrates are usually non-compatible with enzymatic reactions such as PCR due to poisoning of the active center of the enzyme or nonspecific adsorption of the enzymeto the metal surface, which could result in protein denaturation. We present a method for the generation of polymer coatings on metallic surfaces which are designed to minimize protein adsorption and also prevent the release of metal ions. These coatings consist of three layers covalently linked to each other; a self-assembled monolayer to promote adhesion, a photochemically generated barrier layer and a photochemically generated hydrogel. The coatings can be deposited onto aluminum, stainless steel, gold and copper surfaces. We compare PCR efficiencies in the presence of bare metallic surfaces with those of surfaces treated with the novel coating system. Copyright © 2014 Elsevier B.V. All rights reserved.

Superhydrophobic surfaces generated by one-pot spray-coating of chitosan-based nanoparticles.

PubMed

Wang, Shuangfei; Sha, Jiulong; Wang, Wei; Qin, Chengrong; Li, Wei; Qin, Caiqin

2018-09-01

Superhydrophobic surfaces have attracted great attention due to their attractive properties. Biopolymer-based low-cost and environmentally-friendly superhydrophobic coatings with easy-to-perform fabrication methods are always desirable. Herein, we report superhydrophobic surfaces using a one-step spray-coating of chitosan-based nanoparticles. The particles were easily prepared by a nanoprecipitation strategy using synthesized organosoluble chitosan stearoyl ester (CSSE). The resulting particles had an average size of 165 ∼ 235 nm depending on the applied concentration. Subsequently, spray-coating of such particles onto silicon wafer generated a surface with a water contact angle of 155 ± 1°. SEM and AFM images exhibited a nano/microscaled roughness appeared on the coated surface. The superhydrophobic surfaces showed a stable superhydrophobic performance even after storage for 15 days, pH stability between pH 1 to pH 11 and thermal stability until a temperature no more than 50 °C. These properties would broaden the application fields of superhydrophobic surfaces as well as the chitosan itself. Copyright © 2018 Elsevier Ltd. All rights reserved.

Preservation of York Minster historic limestone by hydrophobic surface coatings.

PubMed

Walker, Rachel A; Wilson, Karen; Lee, Adam F; Woodford, Julia; Grassian, Vicki H; Baltrusaitis, Jonas; Rubasinghege, Gayan; Cibin, Giannantonio; Dent, Andrew

2012-01-01

Magnesian limestone is a key construction component of many historic buildings that is under constant attack from environmental pollutants notably by oxides of sulfur via acid rain, particulate matter sulfate and gaseous SO(2) emissions. Hydrophobic surface coatings offer a potential route to protect existing stonework in cultural heritage sites, however, many available coatings act by blocking the stone microstructure, preventing it from 'breathing' and promoting mould growth and salt efflorescence. Here we report on a conformal surface modification method using self-assembled monolayers of naturally sourced free fatty acids combined with sub-monolayer fluorinated alkyl silanes to generate hydrophobic (HP) and super hydrophobic (SHP) coatings on calcite. We demonstrate the efficacy of these HP and SHP surface coatings for increasing limestone resistance to sulfation, and thus retarding gypsum formation under SO(2)/H(2)O and model acid rain environments. SHP treatment of 19th century stone from York Minster suppresses sulfuric acid permeation.

Preservation of York Minster historic limestone by hydrophobic surface coatings

NASA Astrophysics Data System (ADS)

Walker, Rachel A.; Wilson, Karen; Lee, Adam F.; Woodford, Julia; Grassian, Vicki H.; Baltrusaitis, Jonas; Rubasinghege, Gayan; Cibin, Giannantonio; Dent, Andrew

2012-11-01

Magnesian limestone is a key construction component of many historic buildings that is under constant attack from environmental pollutants notably by oxides of sulfur via acid rain, particulate matter sulfate and gaseous SO2 emissions. Hydrophobic surface coatings offer a potential route to protect existing stonework in cultural heritage sites, however, many available coatings act by blocking the stone microstructure, preventing it from `breathing' and promoting mould growth and salt efflorescence. Here we report on a conformal surface modification method using self-assembled monolayers of naturally sourced free fatty acids combined with sub-monolayer fluorinated alkyl silanes to generate hydrophobic (HP) and super hydrophobic (SHP) coatings on calcite. We demonstrate the efficacy of these HP and SHP surface coatings for increasing limestone resistance to sulfation, and thus retarding gypsum formation under SO2/H2O and model acid rain environments. SHP treatment of 19th century stone from York Minster suppresses sulfuric acid permeation.

Laboratory evaluation of polychlorinated biphenyls ...

EPA Pesticide Factsheets

Effectiveness and limitations of the encapsulation method for reducing polychlorinated biphenyls (PCBs) concentrations in indoor air and contaminated surface have been evaluated in the laboratory study. Ten coating materials such as epoxy and polyurethane coatings, latex paint, and petroleum-based paint were tested in small environmental chambers to rank the encapsulants by their resistance to PCB sorption and estimate the key parameters required by a barrier model. Wipe samples were collected from PCB contaminated surface encapsulated with the coating materials to rank the encapsulants by their resistance to PCB migration from the source. A barrier model was used to calculate the PCB concentrations in the sources and the encapsulant layers, and at the exposed surfaces of the encapsulant and in the room air at different times. The performance of the encapsulants was ranked by those concentrations and PCB percent reductions. Overall, the three epoxy coatings performed better than the other coatings. Both the experimental results and the mathematical modeling showed that selecting proper encapsulants can effectively reduce the PCB concentrations at the exposed surfaces. The encapsulation method is most effective for contaminated surfaces that contain low levels of PCBs. This study answers some of these questions by using a combination of laboratory testing and mathematical modeling. The results should be useful to mitigation engineers, building owners and managers

High wear resistance of femoral components coated with titanium nitride: a retrieval analysis.

PubMed

Fabry, Christian; Zietz, Carmen; Baumann, Axel; Ehall, Reinhard; Bader, Rainer

2017-05-20

The objective of this study was to evaluate the in vivo wear resistance of cobalt-chromium femoral components coated with titanium nitride (TiN). Our null hypothesis was that the surface damage and the thickness of the TiN coating do not correlate with the time in vivo. Twenty-five TiN-coated bicondylar femoral retrievals with a mean implantation period of 30.7 ± 11.7 months were subjected to an objective surface damage analysis with a semi-quantitative assessment method. A visual examination of scratches, indentations, notches and coating breakthroughs of the surfaces was performed. The roughness and the coating thickness of the TiN coating were evaluated in the main articulation regions. Narrow scratches and indentations in the range of low flexion angles on the retrieval surfaces were the most common modes of damage. There was no evidence of delamination on the articulation surface but rather at the bottom of isolated severe indentations or notches. An analysis of three retrievals revealed a coating breakthrough in the patellofemoral joint region, resulting from patella maltracking and a dislocation. The arithmetical mean roughness of the TiN surface slightly increased with the implantation period. In contrast, the maximum peak height of the roughness profile was reduced at the condyles of the retrieved components in comparison with new, unused surfaces. No significant association between the coating thickness and implantation period was determined. Moreover, the measured values were retained in the range of the initial coating thickness even after several years of in vivo service. As was demonstrated by the results of this study, the surface damage to the TiN coating did not deteriorate with the implantation period. The calculated damage scores and the measured coating thickness in particular both confirmed that the TiN coating provides low wear rates. Our findings support the use of wear-resistant TiN-coated components in total knee arthroplasty with the objective of reducing the risk of aseptic loosening. However, in terms of TiN-coated femoral components, particular attention should be paid to a correct patellar tracking in order to avoid wear propagation at the implant.

Surface roughness of glass ionomer cements indicated for uncooperative patients according to surface protection treatment

PubMed Central

Pacifici, Edoardo; Bossù, Maurizio; Giovannetti, Agostino; La Torre, Giuseppe; Guerra, Fabrizio; Polimeni, Antonella

2013-01-01

Summary Background Even today, use of Glass Ionomer Cements (GIC) as restorative material is indicated for uncooperative patients. Aim The study aimed at estimating the surface roughness of different GICs using or not their proprietary surface coatings and at observing the interfaces between cement and coating through SEM. Materials and methods Forty specimens have been obtained and divided into 4 groups: Fuji IX (IX), Fuji IX/G-Coat Plus (IXC), Vitremer (V), Vitremer/Finishing Gloss (VFG). Samples were obtained using silicone moulds to simulate class I restorations. All specimens were processed for profilometric evaluation. The statistical differences of surface roughness between groups were assessed using One-Way Analysis of Variance (One-Way ANOVA) (p<0.05). The Two-Way Analysis of Variance (Two-Way ANOVA) was used to evaluate the influence of two factors: restoration material and presence of coating. Coated restoration specimens (IXC and VFG) were sectioned perpendicular to the restoration surface and processed for SEM evaluation. Results No statistical differences in roughness could be noticed between groups or factors. Following microscopic observation, interfaces between restoration material and coating were better for group IXC than for group VFG. Conclusions When specimens are obtained simulating normal clinical procedures, the presence of surface protection does not significantly improve the surface roughness of GICs. PMID:24611090

Influence of polymer coating morphology on microsensor response

NASA Astrophysics Data System (ADS)

Levit, Natalia; Pestov, Dmitry; Tepper, Gary C.

2004-03-01

Nanoscale polymeric coatings are used in a variety of sensor systems. The influence of polymer coating morphology on sensor response was investigated and it was determined that coating morphology plays a particularly important role in transducers based on optical or acoustic resonance such as surface acoustic wave (SAW) or surface plasmon resonance (SPR) devices. Nanoscale polymeric coatings were deposited onto a number of miniature devices using a "solvent-free" deposition technique known as Rapid Expansion of Supercritical Solutions (RESS). In RESS, the supercritical solvent goes into the vapor phase upon fast depressurization and separates from the polymer. Therefore, dry polymer particles are deposited from the gas phase. The average diameter of RESS precipitates is about two orders of magnitude smaller than the minimum droplet size achievable by the air-brush method. For rubbery polymers, such as PIB and PDMS, the nanoscale solute droplets produced by RESS agglomerate on the surface forming a highly-uniform continuous nanoscale film. For glassy and crstalline polymers, the RESS droplets produce uniform particulate coatings exhibiting high surface-to-volume ratio. The coating morphology can be changed by controlling the RESS processing conditions.

Mechanical properties of anodized coatings over molten aluminum alloy

DOE PAGES

Grillet, Anne M.; Gorby, Allen D.; Trujillo, Steven M.; ...

2007-10-22

A method to measure interfacial mechanical properties at high temperatures and in a controlled atmosphere has been developed to study anodized aluminum surface coatings at temperatures where the interior aluminum alloy is molten. This is the first time that the coating strength has been studied under these conditions. In this study, we have investigated the effects of ambient atmosphere, temperature, and surface finish on coating strength for samples of aluminum alloy 7075. Surprisingly, the effective Young's modulus or strength of the coating when tested in air was twice as high as when samples were tested in an inert nitrogen ormore » argon atmosphere. Additionally, the effective Young's modulus of the anodized coating increased with temperature in an air atmosphere but was independent of temperature in an inert atmosphere. The effect of surface finish was also examined. Sandblasting the surface prior to anodization was found to increase the strength of the anodized coating with the greatest enhancement noted for a nitrogen atmosphere. Lastly, machining marks were not found to significantly affect the strength.« less

Fabrication of superhydrophobic surfaces based on ZnO-PDMS nanocomposite coatings and study of its wetting behaviour

NASA Astrophysics Data System (ADS)

Chakradhar, R. P. S.; Kumar, V. Dinesh; Rao, J. L.; Basu, Bharathibai J.

2011-08-01

Superhydrophobic surfaces based on ZnO-PDMS nanocomposite coatings are demonstrated by a simple, facile, time-saving, wet chemical route. ZnO nanopowders with average particle size of 14 nm were synthesized by a low temperature solution combustion method. Powder X-ray diffraction results confirm that the nanopowders exhibit hexagonal wurtzite structure and belong to space group P63 mc. Field emission scanning electron micrographs reveal that the nanoparticles are connected to each other to make large network systems consisting of hierarchical structure. The as formed ZnO coating exhibits wetting behaviour with Water Contact Angle (WCA) of ˜108°, however on modification with polydimethylsiloxane (PDMS), it transforms to superhydrophobic surface with measured contact and sliding angles for water at 155° and less than 5° respectively. The surface properties such as surface free energy ( γp), interfacial free energy ( γpw), and the adhesive work ( Wpw) were evaluated. Electron paramagnetic resonance (EPR) studies on superhydrophobic coatings revealed that the surface defects play a major role on the wetting behaviour. Advantages of the present method include the cheap and fluorine-free raw materials, environmentally benign solvents, and feasibility for applying on large area of different substrates.

Plasma-deposited tetraglyme surfaces greatly reduce total blood protein adsorption, contact activation, platelet adhesion, platelet procoagulant activity, and in vitro thrombus deposition.

PubMed

Cao, Lan; Chang, Mark; Lee, Chi-Ying; Castner, David G; Sukavaneshvar, Sivaprasad; Ratner, Buddy D; Horbett, Thomas A

2007-06-15

The ability of tetraethylene glycol dimethyl ether (tetraglyme) plasma deposited coatings exhibiting ultralow fibrinogen adsorption to reduce blood activation was studied with six in vitro methods, namely fibrinogen and von Willebrand's factor adsorption, total protein adsorption, clotting time in recalcified plasma, platelet adhesion and procoagulant activity, and whole blood thrombosis in a disturbed flow catheter model. Surface plasmon resonance results showed that tetraglyme surfaces strongly resisted the adsorption of all proteins from human plasma. The clotting time in the presence of tetraglyme surfaces was lengthened compared with controls, indicating a lower activation of the intrinsic coagulation cascade. Platelet adhesion and thrombin generation by adherent platelets were greatly reduced on tetraglyme-coated materials, compared with uncoated and Biospan-coated glass slides. In the in vitro disturbed blood flow model, tetraglyme plasma coated catheters had 50% less thrombus than did the uncoated catheters. Tetraglyme-coated materials thus had greatly reduced blood interactions as measured with all six methods. The improved blood compatibility of plasma-deposited tetraglyme is thus not only due to their reduced platelet adhesion and activation, but also to a generalized reduction in blood interactions. (c) 2007 Wiley Periodicals, Inc.

Bubbles versus biofilms: a novel method for the removal of marine biofilms attached on antifouling coatings using an ultrasonically activated water stream

NASA Astrophysics Data System (ADS)

Salta, M.; Goodes, L. R.; Maas, B. J.; Dennington, S. P.; Secker, T. J.; Leighton, T. G.

2016-09-01

The accumulation of marine organisms on a range of manmade surfaces, termed biofouling, has proven to be the Achilles’ heel of the shipping industry. Current antifouling coatings, such as foul release coatings (FRCs), only partially inhibit biofouling, since biofilms remain a major issue. Mechanical ship hull cleaning is commonly employed to remove biofilms, but these methods tend to damage the antifouling coating and often do not result in full removal. Here, we report the effectiveness of biofilm removal from FRCs through a novel cleaning device that uses an ultrasonically activated stream (UAS). In this device, ultrasound enhances the cleaning properties of microbubbles in a freely flowing stream of water. The UAS was applied on two types of commercial FRCs which were covered with biofilm growth following twelve days immersion in the marine environment. Biofilm removal was quantified in terms of reduction in biovolume and surface roughness, both measured using an optical profilometer, which were then compared with similar measurements after cleaning with a non-ultrasonically activated water stream. It was found that the UAS significantly improves the cleaning capabilities of a water flow, up to the point where no detectable biofilm remained on the coating surfaces. Overall biofilm surface coverage was significantly lower on the FRC coatings cleaned with the UAS system when compared to the coatings cleaned with water or not cleaned at all. When biofilm biomass removal was investigated, the UAS system resulted in significantly lower biovolume values even when compared to the water cleaning treatment with biovolume values close to zero. Remarkably, the surface roughness of the coatings after cleaning with the UAS was found to be comparable to that of the blank, non-immersed coatings, illustrating that the UAS did not damage the coatings in the process. The data supporting this study are openly available from the University of Southampton repository at http://dx.doi.org/10.5258/SOTON/399420.

Mechanical properties of PEO-coatings on the surface of magnesium alloy MA8 modified by TiN nanoparticles

NASA Astrophysics Data System (ADS)

Imshinetsky, Igor M.; Mashtalyar, Dmitriy V.; Sunebryukhov, Sergey L.; Gnedenkov, Sergey V.

2017-09-01

The methods to form protective coatings by the plasma electrolytic oxidation method (PEO) in the electrolytic system containing nanosized particles of titanium nitride has been develoted. Tribological and morfological studies of the composite coatings have been carried out. It has been established that the microhardness of the coating with nanoparticles concentration of 3 g/l increases by 2 folds, while the wear resistance - by 2.2 fold, as compared to respective values for the PEO-coating formed in the electrolyte without nanoparticles.

Study on the neotype zirconia's implant coated nanometer hydroxyapatite ceramics

NASA Astrophysics Data System (ADS)

Zhu, J. W.; Yang, D. W.

2007-07-01

In recent years, biologic ceramics is a popular material of implants and bioactive surface modification of dental implant became a research emphasis, which aims to improve bioactivity of implants materials and acquire firmer implants-bone interface. The zirconia ceramic has excellent mechanical properties and nanometer HA ceramics is a bioceramic well known for its bioactivity, therefore, nanometer HA ceramics coating on zirconia, allows combining the excellent mechanical properties of zirconia substrates with its bioactivity. This paper shows a new method for implant shape design and bioactive modification of dental implants surface. Zirconia's implant substrate was prepared by sintered method, central and lateral tunnels were drilled in the zirconia hollow porous cylindrical implants by laser processing. The HA powders and needle-like HA crystals were made by a wet precipitation and calcining method. Its surface was coated with nanometer HA ceramics which was used brush HA slurry and vacuum sintering. Mechanical testing results revealed that the attachment strength of nanometer HA ceramics coated zirconia samples is high. SEM and interface observation after inserted experiment indicated that calcium and phosphor content increased and symmetrically around coated implant-bone tissue interface. A significantly higher affinity index was demonstrated in vivo by histomorphometric evaluation in coated versus uncoated implants. SEM analysis demonstrated better bone adhesion to the material in coated implant at any situation. In addition, the hollow porous cylindrical implant coated with nanometer HA ceramics increase the interaction of bone and implant, the new bone induced into the surface of hollow porous cylindrical implant and through the most tunnels filled into central hole. The branch-like structure makes the implant and bone a body, which increased the contact area and decreased elastic ratio. Therefore, the macroscopical and microcosmic nested structure of implant coated nanometer HA ceramics had increased biocompatibility and improved the osteointegration. It endows the implants with new vital activity.

Method for nanoencapsulation of aerogels and nanoencapsulated aerogels produced by such method

NASA Technical Reports Server (NTRS)

Sullivan, Thomas A. (Inventor)

2007-01-01

A method for increasing the compressive modulus of aerogels comprising: providing aerogel substrate comprising a bubble matrix in a chamber; providing monomer to the chamber, the monomer comprising vapor phase monomer which polymerizes substantially free of polymerization byproducts; depositing monomer from the vapor phase onto the surface of the aerogel substrate under deposition conditions effective to produce a vapor pressure sufficient to cause the vapor phase monomer to penetrate into the bubble matrix and deposit onto the surface of the aerogel substrate, producing a substantially uniform monomer film; and, polymerizing the substantially uniform monomer film under polymerization conditions effective to produce polymer coated aerogel comprising a substantially uniform polymer coating substantially free of polymerization byproducts.Polymer coated aerogel comprising aerogel substrate comprising a substantially uniform polymer coating, said polymer coated aerogel comprising porosity and having a compressive modulus greater than the compressive modulus of the aerogel substrate, as measured by a 100 lb. load cell at 1 mm/minute in the linear range of 20% to 40% compression.

Spray-coating process in preparing PTFE-PPS composite super-hydrophobic coating

NASA Astrophysics Data System (ADS)

Weng, Rui; Zhang, Haifeng; Liu, Xiaowei

2014-03-01

In order to improve the performance of a liquid-floated rotor micro-gyroscope, the resistance of the moving interface between the rotor and the floating liquid must be reduced. Hydrophobic treatment can reduce the frictional resistance between such interfaces, therefore we proposed a method to prepare a poly-tetrafluoroethylene (PTFE)-poly-phenylene sulphide (PPS) composite super-hydrophobic coating, based on a spraying process. This method can quickly prepare a continuous, uniform PTFE-PPS composite super-hydrophobic surface on a 2J85 material. This method can be divided into three steps, namely: pre-treatment; chemical etching; and spraying. The total time for this is around three hours. When the PTFE concentration is 4%, the average contact angle of the hydrophobic coating surface is 158°. If silicon dioxide nanoparticles are added, this can further improve the adhesion and mechanical strength of the super-hydrophobic composite coating. The maximum average contact angle can reach as high as 164° when the mass fraction of PTFE, PPS and silicon dioxide is 1:1:1.

From Coating to Dopant: How the Transition Metal Composition Affects Alumina Coatings on Ni-Rich Cathodes

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

Han, Binghong; Key, Baris; Lapidus, Saul H.

Surface alumina coatings have been shown to be an effective way to improve the stability and cyclability of cathode materials. However, a detailed understanding of the relationship between the surface coatings and the bulk layered oxides is needed to better define the critical cathode–electrolyte interface. In this work, we systematically studied the effect of the composition of Ni-rich LiNi xMn yCo 1–x–yO 2 (NMC) on the surface alumina coatings. Changing cathode composition from LiNi 0.5Mn 0.3Co 0.2O 2 (NMC532) to LiNi 0.6Mn 0.2Co 0.2O 2 (NMC622) and LiNi 0.8Mn 0.1Co 0.1O 2 (NMC811) was found to facilitate the diffusion ofmore » surface alumina into the bulk after high-temperature annealing. By use of a variety of spectroscopic techniques, Al was seen to have a high bulk compatibility with higher Ni/Co content, and low bulk compatibility was associated with Mn in the transition metal layer. It was also noted that the cathode composition affected the observed morphology and surface chemistry of the coated material, which has an effect on electrochemical cycling. The presence of a high surface Li concentration and strong alumina diffusion into the bulk led to a smoother surface coating on NMC811 with no excess alumina aggregated on the surface. Structural characterization of pristine NMC particles also suggests surface Co segregation, which may act to mediate the diffusion of the Al from the surface to the bulk. The diffusion of Al into the bulk was found to be detrimental to the protection function of surface coatings leading to poor overall cyclability, indicating the importance of compatibility between surface coatings and bulk oxides on the electrochemical performance of coated cathode materials.In conclusion, these results are important in developing a better coating method for synthesis of next-generation cathode materials for lithium-ion batteries.« less

From Coating to Dopant: How the Transition Metal Composition Affects Alumina Coatings on Ni-Rich Cathodes

DOE PAGES

Han, Binghong; Key, Baris; Lapidus, Saul H.; ...

2017-11-01

Surface alumina coatings have been shown to be an effective way to improve the stability and cyclability of cathode materials. However, a detailed understanding of the relationship between the surface coatings and the bulk layered oxides is needed to better define the critical cathode–electrolyte interface. In this work, we systematically studied the effect of the composition of Ni-rich LiNi xMn yCo 1–x–yO 2 (NMC) on the surface alumina coatings. Changing cathode composition from LiNi 0.5Mn 0.3Co 0.2O 2 (NMC532) to LiNi 0.6Mn 0.2Co 0.2O 2 (NMC622) and LiNi 0.8Mn 0.1Co 0.1O 2 (NMC811) was found to facilitate the diffusion ofmore » surface alumina into the bulk after high-temperature annealing. By use of a variety of spectroscopic techniques, Al was seen to have a high bulk compatibility with higher Ni/Co content, and low bulk compatibility was associated with Mn in the transition metal layer. It was also noted that the cathode composition affected the observed morphology and surface chemistry of the coated material, which has an effect on electrochemical cycling. The presence of a high surface Li concentration and strong alumina diffusion into the bulk led to a smoother surface coating on NMC811 with no excess alumina aggregated on the surface. Structural characterization of pristine NMC particles also suggests surface Co segregation, which may act to mediate the diffusion of the Al from the surface to the bulk. The diffusion of Al into the bulk was found to be detrimental to the protection function of surface coatings leading to poor overall cyclability, indicating the importance of compatibility between surface coatings and bulk oxides on the electrochemical performance of coated cathode materials.In conclusion, these results are important in developing a better coating method for synthesis of next-generation cathode materials for lithium-ion batteries.« less

Facile Synthesis of Smart Nanocontainers as Key Components for Construction of Self-Healing Coating with Superhydrophobic Surfaces.

PubMed

Liang, Yi; Wang, MingDong; Wang, Cheng; Feng, Jing; Li, JianSheng; Wang, LianJun; Fu, JiaJun

2016-12-01

SiO2-imidazoline nanocomposites (SiO2-IMI) owning high loading capacity of corrosion inhibitor, 1-hexadecyl-3-methylimidazolium bromide (HMID), and a special acid/alkali dual-stimuli-accelerated release property have been synthesized via a one-step modified Stöber method. SiO2-IMI were uniformly distributed into the hydrophobic SiO2 sol to construct "host"-"guest" feedback active coating with a superhydrophobic surface (SiO2-IMI@SHSC) on aluminium alloy, AA2024, by dip-coating technique. SiO2-IMI as "guest" components have good compatibility with "host" sol-gel coating, and more importantly, once localized corrosion occurs on the surface of AA2024, SiO2-IMI can simultaneously respond to the increase in environmental pH around corrosive micro-cathodic regions and decrease in pH near micro-anodic regions, promptly releasing HMID to form a compact molecular film on the damaged surface, inhibiting corrosion spread and executing a self-healing function. The scanning vibrating electrode technique (SVET) was applied to illustrate the suppression process of cathodic/anodic corrosion activities. Furthermore, benefiting from the superhydrophobic surface, SiO2-IMI@SHSC remained its protective ability after immersion in 0.5 M NaCl solution for 35 days, which is far superior to the conventional sol-gel coating with the same coating thickness. The facile fabrication method of SiO2-IMI simplifies the construction procedure of SiO2-IMI@SHSC, which have great potential to replace non-environmental chromate conversion coatings for practical use.

Facile silicification of plastic surface for bioassays

PubMed Central

Hong, Seonki; Park, Ki Soo; Weissleder, Ralph; Castro, Cesar M.; Lee, Hakho

2017-01-01

We herein report a biomimetic technique to modify plastic substrates for bioassays. The method first places a polydopamine adhesion layer to plastic surface, and then grows conformal silica coating. As proof of principle, we coated plastic microbeads to construct a disposable filter for point-of-care nucleic acid extraction. PMID:28134385

Silica Nanoparticles Functionalized with Zwitterionic Sulfobetaine Siloxane for Application as a Versatile Antifouling Coating System.

PubMed

Knowles, Brianna R; Wagner, Pawel; Maclaughlin, Shane; Higgins, Michael J; Molino, Paul J

2017-06-07

The growing need to develop surfaces able to effectively resist biological fouling has resulted in the widespread investigation of nanomaterials with potential antifouling properties. However, the preparation of effective antifouling coatings is limited by the availability of reactive surface functional groups and our ability to carefully control and organize chemistries at a materials' interface. Here, we present two methods of preparing hydrophilic low-fouling surface coatings through reaction of silica-nanoparticle suspensions and predeposited silica-nanoparticle films with zwitterionic sulfobetaine (SB). Silica-nanoparticle suspensions were functionalized with SB across three pH conditions and deposited as thin films via a simple spin-coating process to generate hydrophilic antifouling coatings. In addition, coatings of predeposited silica nanoparticles were surface functionalized via exposure to zwitterionic solutions. Quartz crystal microgravimetry with dissipation monitoring was employed as a high throughput technique for monitoring and optimizing reaction to the silica-nanoparticle surfaces. Functionalization of nanoparticle films was rapid and could be achieved over a wide pH range and at low zwitterion concentrations. All functionalized particle surfaces presented a high degree of wettability and resulted in large reductions in adsorption of bovine serum albumin protein. Particle coatings also showed a reduction in adhesion of fungal spores (Epicoccum nigrum) and bacteria (Escherichia coli) by up to 87 and 96%, respectively. These results indicate the potential for functionalized nanosilicas to be further developed as versatile fouling-resistant coatings for widespread coating applications.

Solar radiation on Mars: Stationary photovoltaic array

NASA Technical Reports Server (NTRS)

Appelbaum, J.; Sherman, I.; Landis, G. A.

1993-01-01

Solar energy is likely to be an important power source for surface-based operation on Mars. Photovoltaic cells offer many advantages. In this article we have presented analytical expressions and solar radiation data for stationary flat surfaces (horizontal and inclined) as a function of latitude, season and atmospheric dust load (optical depth). The diffuse component of the solar radiation on Mars can be significant, thus greatly affecting the optimal inclination angle of the photovoltaic surface.

Desert Research and Technology Studies Exposure of Lotus Coated Electrodynamic Shield Samples. Part 2

NASA Technical Reports Server (NTRS)

Margiotta, Danielle V.; McKittrick, Kristin R.; Straka, Sharon A.; Jones, Craig B.

2012-01-01

The passive Lotus dust mitigation coating currently being developed at NASA's Goddard Space Flight Center (GSFC), was selected by the Habitation Demonstration Unit Deep Space Habitat (HDU-DSH) for participation in the 2011 Desert Research and Technology Studies (D-RaTS). Based on the unique surface architecture of the Lotus leaf, the nano-engineered Lotus coating seeks to replicate these structures on space flight and habitation surfaces. By decreasing both the surface energy and area for particle attachment, the Lotus coating greatly diminishes dust accumulation on surfaces. This is a problem that can be encountered on lunar, Martian, and asteroid missions. Two different application methods of this coating were tested in summer 2011 at the D-RaTS site: the wet chemistry applied version and combustion chemical vapor deposition (CCVD) applied version. These Lotus coatings, along with two common thermal control coatings, were combined with the active dust mitigation electrodynamic shield (EDS) technology developed at Kennedy Space Center (KSC). The EDS technology uses an electrified grid to remove dust particles from the surface of a Kapton (Trademark) substrate. The Lotus coating and thermal control coatings were applied to these Kapton (Trademark) substrates for testing. The combination of these two innovations was theorized to be an applicable countermeasure for addressing dust accumulation during long-duration human space exploration. This theory was tested and characterized prior to, during, and after D-RaTS exposure.

Mg-MOF-74/MgF2 Composite Coating for Improving the Properties of Magnesium Alloy Implants: Hydrophilicity and Corrosion Resistance

PubMed Central

Liu, Wei; Yan, Zhijie; Ma, Xiaolu; Geng, Tie; Wu, Haihong

2018-01-01

Surface modification on Mg alloys is highly promising for their application in the field of bone repair. In this study, a new metal–organic framework/MgF2 (Mg-MOF-74/MgF2) composite coating was prepared on the surface of AZ31B Mg alloy via pre-treatment of hydrofluoric acid and in situ hydrothermal synthesis methods. The surface topography of the composite coating is compact and homogeneous, and Mg-MOF-74 has good crystallinity. The corrosion resistance of this composite coating was investigated through Tafel polarization test and immersion test in simulated body fluid at 37 °C. It was found that Mg-MOF-74/MgF2 composite coating significantly slowed down the corrosion rate of Mg alloy. Additionally, Mg-MOF-74/MgF2 composite coating expresses super-hydrophilicity with the water contact angle of nearly 0°. In conclusion, on the basis of MgF2 anticorrosive coating, the introduction of Mg-MOF-74 further improves the biological property of Mg alloys. At last, we propose that the hydrophilicity of the composite coating is mainly owing to the large number of hydroxyl groups, the high specific surface area of Mg-MOF-74, and the rough coating produced by Mg-MOF-74 particles. Hence, Mg-MOF-74 has a great advantage in enhancing the hydrophilicity of Mg alloy surface. PMID:29518933

Mg-MOF-74/MgF₂ Composite Coating for Improving the Properties of Magnesium Alloy Implants: Hydrophilicity and Corrosion Resistance.

PubMed

Liu, Wei; Yan, Zhijie; Ma, Xiaolu; Geng, Tie; Wu, Haihong; Li, Zhongyue

2018-03-07

Surface modification on Mg alloys is highly promising for their application in the field of bone repair. In this study, a new metal-organic framework/MgF₂ (Mg-MOF-74/MgF₂) composite coating was prepared on the surface of AZ31B Mg alloy via pre-treatment of hydrofluoric acid and in situ hydrothermal synthesis methods. The surface topography of the composite coating is compact and homogeneous, and Mg-MOF-74 has good crystallinity. The corrosion resistance of this composite coating was investigated through Tafel polarization test and immersion test in simulated body fluid at 37 °C. It was found that Mg-MOF-74/MgF₂ composite coating significantly slowed down the corrosion rate of Mg alloy. Additionally, Mg-MOF-74/MgF₂ composite coating expresses super-hydrophilicity with the water contact angle of nearly 0°. In conclusion, on the basis of MgF₂ anticorrosive coating, the introduction of Mg-MOF-74 further improves the biological property of Mg alloys. At last, we propose that the hydrophilicity of the composite coating is mainly owing to the large number of hydroxyl groups, the high specific surface area of Mg-MOF-74, and the rough coating produced by Mg-MOF-74 particles. Hence, Mg-MOF-74 has a great advantage in enhancing the hydrophilicity of Mg alloy surface.

Thermal input control and enhancement for laser based residual stress measurements using liquid temperature indicating coatings

DOEpatents

Pechersky, M.J.

1999-07-06

An improved method for measuring residual stress in a material is disclosed comprising the steps of applying a spot of temperature indicating coating to the surface to be studied, establishing a speckle pattern surrounds the spot of coating with a first laser then heating the spot of coating with a far infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress during heating and enables calculation of the stress. 3 figs.

Thermal input control and enhancement for laser based residual stress measurements using liquid temperature indicating coatings

DOEpatents

Pechersky, Martin J.

1999-01-01

An improved method for measuring residual stress in a material comprising the steps of applying a spot of temperature indicating coating to the surface to be studied, establishing a speckle pattern surrounds the spot of coating with a first laser then heating the spot of coating with a far infrared laser until the surface plastically deforms. Comparing the speckle patterns before and after deformation by subtracting one pattern from the other will produce a fringe pattern that serves as a visual and quantitative indication of the degree to which the plasticized surface responded to the stress during heating and enables calculation of the stress.

Development & characterization of alumina coating by atmospheric plasma spraying

NASA Astrophysics Data System (ADS)

Sebastian, Jobin; Scaria, Abyson; Kurian, Don George

2018-03-01

Ceramic coatings are applied on metals to prevent them from oxidation and corrosion at room as well as elevated temperatures. The service environment, mechanisms of protection, chemical and mechanical compatibility, application method, control of coating quality and ability of the coating to be repaired are the factors that need to be considered while selecting the required coating. The coatings based on oxide materials provides high degree of thermal insulation and protection against oxidation at high temperatures for the underlying substrate materials. These coatings are usually applied by the flame or plasma spraying methods. The surface cleanliness needs to be ensured before spraying. Abrasive blasting can be used to provide the required surface roughness for good adhesion between the substrate and the coating. A pre bond coat like Nickel Chromium can be applied on to the substrate material before spraying the oxide coating to avoid chances of poor adhesion between the oxide coating and the metallic substrate. Plasma spraying produces oxide coatings of greater density, higher hardness, and smooth surface finish than that of the flame spraying process Inert gas is often used for generation of plasma gas so as to avoid the oxidation of the substrate material. The work focuses to develop, characterize and optimize the parameters used in Al2O3 coating on transition stainless steel substrate material for minimizing the wear rate and maximizing the leak tightness using plasma spray process. The experiment is designed using Taguchi’s L9 orthogonal array. The parameters that are to be optimized are plasma voltage, spraying distance and the cooling jet pressure. The characterization techniques includes micro-hardness and porosity tests followed by Grey relational analysis of the results.

Colloids with high-definition surface structures

PubMed Central

Chen, Hsien-Yeh; Rouillard, Jean-Marie; Gulari, Erdogan; Lahann, Joerg

2007-01-01

Compared with the well equipped arsenal of surface modification methods for flat surfaces, techniques that are applicable to curved, colloidal surfaces are still in their infancy. This technological gap exists because spin-coating techniques used in traditional photolithographic processes are not applicable to the curved surfaces of spherical objects. By replacing spin-coated photoresist with a vapor-deposited, photodefinable polymer coating, we have now fabricated microstructured colloids with a wide range of surface patterns, including asymmetric and chiral surface structures, that so far were typically reserved for flat substrates. This high-throughput method can yield surface-structured colloidal particles at a rate of ≈107 to 108 particles per operator per day. Equipped with spatially defined binding pockets, microstructured colloids can engage in programmable interactions, which can lead to directed self-assembly. The ability to create a wide range of colloids with both simple and complex surface patterns may contribute to the genesis of previously unknown colloidal structures and may have important technological implications in a range of different applications, including photonic and phononic materials or chemical sensors. PMID:17592149

Effect of inclination and anteversion angles on kinematics and contact mechanics of dual mobility hip implants.

PubMed

Gao, Yongchang; Chen, Zhenxian; Zhang, Zhifeng; Chen, Shibin; Jin, Zhongmin

2018-06-12

Steep inclination and excessive anteversion angles of acetabular cups could result in adverse edge-loading. This, in turn, increases contact pressure and impingement risk for traditional artificial hip joints. However, the influence of high inclination and anteversion angles on both the kinematics and contact mechanics of dual mobility hip implants has rarely been examined. This study focuses on investigating both the kinematics and contact mechanics of a dual mobility hip implant under different inclination and anteversion angles using a dynamic explicit finite element method developed in a previous study. The results showed that an inclination angle of both the back shell and liner ranging from 30° to 70° had little influence on the maximum contact pressure and the accumulated sliding distance of inner and outer surfaces of the liner under normal walking gait. The same results were obtained for an anteversion angle of the liner varying between -20° and +20°. However, when the anteversion angle of the liner was beyond this range, the contact between the femoral neck and the inner rim of the liner occurred. Consequently, this caused a relative rotation at the outer articulation. This suggests that both inclination and modest anteversion angles have little influence on the kinematics and contact mechanics of dual mobility hip implants. However, too excessive anteversion angle could result in a rotation for this kind of hip implant at both articulations. Copyright © 2018 Elsevier Ltd. All rights reserved.

Anti-diffusion metal coated O-rings

DOEpatents

Biallas, George Herman; Boyce, James Reid

2016-03-22

A method for inhibiting diffusion of gases and/or transmission of photons through elastomeric seals and a diffusion inhibiting elastomeric seal wherein at least a portion of the surface of a diffusion inhibiting elastomeric seal is coated with a compatibly-deformable, malleable metal coating.

Electrophoretic deposition of dexamethasone-loaded gelatin nanospheres/chitosan coating and its dual function in anti-inflammation and osteogenesis.

PubMed

Qi, Hongfei; Chen, Qiang; Ren, Hailong; Wu, Xianglong; Liu, Xianhu; Lu, Tingli

2018-05-18

Surface modification of metallic implants with bioactive and biodegradable coatings could be a promising approach for bone regeneration. The objective of this study was to prepare chitosan/gelatin nanospheres (GNs) composite coating for the delivery of dexamethasone (DEX). GNs with narrow size distribution and negative surface charge were firstly prepared by a two-step desolvation method. Homogeneous and stable gelatin nanospheres/chitosan (GNs/CTS) composite coatings were formed by electrophoretic deposition (EPD). Drug loading, encapsulation efficiency and in vitro release of DEX were estimated using high performance liquid chromatography (HPLC). The anti-inflammatory effect of DEX-loaded coatings on macrophage RAW 264.7 cells was assessed by the secretion of tumour necrosis factor (TNF) and inducible nitric oxide synthase (iNOS). Osteogenic differentiation of MC3T3-E1 osteoblasts on DEX-loaded coatings was investigated by osteogenic gene expression and mineralization. The DEX in GNs/CTS composite coating showed a two-stage release pattern could not only suppress inflammation during the burst release period, but also promote osteogenic differentiation in the sustained release period. This study might offer a feasible method for modifying the surface of metallic implants in bone regeneration. Copyright © 2018 Elsevier B.V. All rights reserved.

Robust Superhydrophobic Graphene-Based Composite Coatings with Self-Cleaning and Corrosion Barrier Properties.

PubMed

Nine, Md J; Cole, Martin A; Johnson, Lucas; Tran, Diana N H; Losic, Dusan

2015-12-30

Superhydrophobic surfaces for self-cleaning applications often suffer from mechanical instability and do not function well after abrasion/scratching. To address this problem, we present a method to prepare graphene-based superhydrophobic composite coatings with robust mechanical strength, self-cleaning, and barrier properties. A suspension has been formulated that contains a mixture of reduced graphene oxide (rGO) and diatomaceous earth (DE) modified with polydimethylsiloxane (PDMS) that can be applied on any surface using common coating methods such as spraying, brush painting, and dip coating. Inclusion of TiO2 nanoparticles to the formulation shows further increase in water contact angle (WCA) from 159 ± 2° to 170 ± 2° due to the structural improvement with hierarchical surface roughness. Mechanical stability and durability of the coatings has been achieved by using a commercial adhesive to bond the superhydrophobic "paint" to various substrates. Excellent retention of superhydrophobicity was observed even after sandpaper abrasion and crosscut scratching. A potentiodynamic polarization study revealed excellent corrosion resistance (96.78%) properties, and an acid was used to provide further insight into coating barrier properties. The ease of application and remarkable properties of this graphene-based composite coating show considerable potential for broad application as a self-cleaning and protective layer.

Experiment Research on Hot-Rolling Processing of Nonsmooth Pit Surface.

PubMed

Gu, Yun-Qing; Fan, Tian-Xing; Mou, Jie-Gang; Yu, Wei-Bo; Zhao, Gang; Wang, Evan

2016-01-01

In order to achieve the nonsmooth surface drag reduction structure on the inner polymer coating of oil and gas pipelines and improve the efficiency of pipeline transport, a structural model of the machining robot on the pipe inner coating is established. Based on machining robot, an experimental technique is applied to research embossing and coating problems of rolling-head, and then the molding process rules under different conditions of rolling temperatures speeds and depth are analyzed. Also, an orthogonal experiment analysis method is employed to analyze the different effects of hot-rolling process apparatus on the embossed pits morphology and quality of rolling. The results also reveal that elevating the rolling temperature or decreasing the rolling speed can also improve the pit structure replication rates of the polymer coating surface, and the rolling feed has little effect on replication rates. After the rolling-head separates from the polymer coating, phenomenon of rebounding and refluxing of the polymer coating occurs, which is the reason of inability of the process. A continuous hot-rolling method for processing is used in the robot and the hot-rolling process of the processing apparatus is put in a dynamics analysis.

Experiment Research on Hot-Rolling Processing of Nonsmooth Pit Surface

PubMed Central

Gu, Yun-qing; Fan, Tian-xing; Mou, Jie-gang; Yu, Wei-bo; Zhao, Gang; Wang, Evan

2016-01-01

In order to achieve the nonsmooth surface drag reduction structure on the inner polymer coating of oil and gas pipelines and improve the efficiency of pipeline transport, a structural model of the machining robot on the pipe inner coating is established. Based on machining robot, an experimental technique is applied to research embossing and coating problems of rolling-head, and then the molding process rules under different conditions of rolling temperatures speeds and depth are analyzed. Also, an orthogonal experiment analysis method is employed to analyze the different effects of hot-rolling process apparatus on the embossed pits morphology and quality of rolling. The results also reveal that elevating the rolling temperature or decreasing the rolling speed can also improve the pit structure replication rates of the polymer coating surface, and the rolling feed has little effect on replication rates. After the rolling-head separates from the polymer coating, phenomenon of rebounding and refluxing of the polymer coating occurs, which is the reason of inability of the process. A continuous hot-rolling method for processing is used in the robot and the hot-rolling process of the processing apparatus is put in a dynamics analysis. PMID:27022235

Enhancement and Prediction of Adhesion Strength of Copper Cold Spray Coatings on Steel Substrates for Nuclear Fuel Repository

NASA Astrophysics Data System (ADS)

Fernández, R.; MacDonald, D.; Nastić, A.; Jodoin, B.; Tieu, A.; Vijay, M.

2016-12-01

Thick copper coatings have been envisioned as corrosion protection barriers for steel containers used in repositories for nuclear waste fuel bundles. Due to its high deposition rate and low oxidation levels, cold spray is considered as an option to produce these coatings as an alternative to traditional machining processes to create corrosion protective sleeves. Previous investigations on the deposition of thick cold spray copper coatings using only nitrogen as process gas on carbon steel substrates have continuously resulted in coating delamination. The current work demonstrates the possibility of using an innovative surface preparation process, forced pulsed waterjet, to induce a complex substrate surface morphology that serves as anchoring points for the copper particles to mechanically adhere to the substrate. The results of this work show that, through the use of this surface preparation method, adhesion strength can be drastically increased, and thick copper coatings can be deposited using nitrogen. Through finite element analysis, it was shown that it is likely that the bonding created is purely mechanical, explaining the lack of adhesion when conventional substrate preparation methods are used and why helium is usually required as process gas.

Apparatus for coating a surface with a metal utilizing a plasma source

DOEpatents

Brown, I.G.; MacGill, R.A.; Galvin, J.E.

1991-05-07

An apparatus and method are disclosed for coating or layering a surface with a metal utilizing a metal vapor vacuum arc plasma source. The apparatus includes a trigger mechanism for actuating the metal vacuum vapor arc plasma source in a pulsed mode at a predetermined rate. The surface or substrate to be coated or layered is supported in position with the plasma source in a vacuum chamber. The surface is electrically biased for a selected period of time during the pulsed mode of operation of the plasma source. Both the pulsing of the metal vapor vacuum arc plasma source and the electrical biasing of the surface are synchronized for selected periods of time. 10 figures.

Apparatus for coating a surface with a metal utilizing a plasma source

DOEpatents

Brown, Ian G.; MacGill, Robert A.; Galvin, James E.

1991-01-01

An apparatus and method for coating or layering a surface with a metal utilizing a metal vapor vacuum arc plasma source. The apparatus includes a trigger mechanism for actuating the metal vacuum vapor arc plasma source in a pulsed mode at a predetermined rate. The surface or substrate to be coated or layered is supported in position with the plasma source in a vacuum chamber. The surface is electrically biased for a selected period of time during the pulsed mode of operation of the plasma source. Both the pulsing of the metal vapor vacuum arc plasma source and the electrical biasing of the surface are synchronized for selected periods of time.

Electromechanical properties of polyamide/lycra fabric treated with PEDOT:PSS

NASA Astrophysics Data System (ADS)

Tadesse, M. G.; Mengistie, D. A.; Loghin, C.; Chen, Y.; Wang, L.; Catalin, D.; Müller, C.; Nierstrasz, V.

2017-10-01

One of the challenges in smart textiles is to develop suitable multifunctional materials that can address simultaneously several characteristics such as durability, stretchability, lightweight, and conductivity. Conductive polymers which showed success in different technological fields like polymer solar cells and light emitting diodes are promising in many smart textile applications. In this work, we treated a common polyamide/lycra knitted fabric with PEDOT:PSS for stretchable e-textiles. PEDOT:PSS, with DMSO as a conductivity enhancer and different ratios of water-based polyurethane dispersions as a binder, was applied to the fabric with simple immersion and coating applications. The effect of different application methods and binder ratio on the surface resistance of the fabric was monitored with four point probe electrical surface resistance measurement systems. Samples prepared by immersion technique are more uniform and have higher conductivity than those prepared by a coating technique. SEM images showed that PEDOT:PSS is incorporated into the structure in the immersion method while in the coating it is majorly present on the surface of the fabric. The tensile measurement showed that the acidic PEDOT:PSS and polyurethane dispersion coating has no adverse effect on the tensile strength of the fabric. The coated samples can be stretched up to 700% while still reasonably conductive. The resistance increases only by a small amount when samples were stretched cyclically by stretching 100%. Generally, samples prepared by the immersion method maintained better conductivity while stretching than those by a coating method. The washing fastness of the samples was also assessed.

Plasma-sprayed CaTiSiO5 ceramic coating on Ti-6Al-4V with excellent bonding strength, stability and cellular bioactivity.

PubMed

Wu, Chengtie; Ramaswamy, Yogambha; Liu, Xuanyong; Wang, Guocheng; Zreiqat, Hala

2009-02-06

Novel Ca-Si-Ti-based sphene (CaTiSiO5) ceramics possess excellent chemical stability and cytocompatibility. The aim of this study was to prepare sphene coating on titanium alloy (Ti-6Al-4V) for orthopaedic applications using the plasma spray method. The phase composition, surface and interface microstructure, coating thickness, surface roughness and bonding strength of the plasma-sprayed sphene coating were analysed using X-ray diffraction, scanning electron microscopy, atomic force microscopy and the standard mechanical testing of the American Society for Testing and Materials, respectively. The results indicated that sphene coating was obtained with a uniform and dense microstructure at the interface of the Ti-6Al-4V surface and the thickness and surface roughness of the coating were approximately 150 and 10 microm, respectively. Plasma-sprayed sphene coating on Ti-6Al-4V possessed a significantly improved bonding strength and chemical stability compared with plasma-sprayed hydroxyapatite (HAp) coating. Plasma-sprayed sphene coating supported human osteoblast-like cell (HOB) attachment and significantly enhanced HOB proliferation and differentiation compared with plasma-sprayed HAp coating and uncoated Ti-6Al-4V. Taken together, plasma-sprayed sphene coating on Ti-6Al-4V possessed excellent bonding strength, chemical stability and cellular bioactivity, indicating its potential application for orthopaedic implants.

Anticorrosion performance of chromized coating prepared by pack cementation in simulated solution with H2S and CO2

NASA Astrophysics Data System (ADS)

Wang, Qin-Ying; Behnamian, Yashar; Luo, Hong; Wang, Xian-Zong; Leitch, Michael; Zeng, Hongbo; Luo, Jing-Li

2017-10-01

A hash service environment containing H2S and CO2 in oil industry usually causes corrosion of carbon steel. In this study, the chromized coatings with different deposited time were prepared on the surface of carbon steel by the method of pack cementation to enhance its corrosion resistance. Then the microstructure, hardness, corrosion resistance as well as the semiconductor behavior of coatings in the simulated solution with saturated H2S and CO2 were investigated. The results show that the content of Cr in coating was increased by prolonging deposited time, and both chromium carbides and chromium nitrides were formed. Furthermore, coatings display higher polarization resistance, Rp, than that of the substrate, indicating a higher resistance to charge transfer on coating surface. The corrosion rates of coatings with different deposited time were significantly lower than that of substrate. Chemical analysis showed the formation of heavy sulfides on the surface of substrates after corrosion, while the least corrosion products were detected on the surface of coating with deposited time of 12 h. Mott-Schottky results indicated that coating of 12 h displayed less defects than the other two coatings with deposited time of 4 h and 8 h, which will be beneficial to improve corrosion resistance. The investigation showed that chromized coatings exhibited high corrosion resistance and owned a potential application in oil industry for corrosion prevention.

Plasma-sprayed CaTiSiO5 ceramic coating on Ti-6Al-4V with excellent bonding strength, stability and cellular bioactivity

PubMed Central

Wu, Chengtie; Ramaswamy, Yogambha; Liu, Xuanyong; Wang, Guocheng; Zreiqat, Hala

2008-01-01

Novel Ca-Si-Ti-based sphene (CaTiSiO5) ceramics possess excellent chemical stability and cytocompatibility. The aim of this study was to prepare sphene coating on titanium alloy (Ti-6Al-4V) for orthopaedic applications using the plasma spray method. The phase composition, surface and interface microstructure, coating thickness, surface roughness and bonding strength of the plasma-sprayed sphene coating were analysed using X-ray diffraction, scanning electron microscopy, atomic force microscopy and the standard mechanical testing of the American Society for Testing and Materials, respectively. The results indicated that sphene coating was obtained with a uniform and dense microstructure at the interface of the Ti-6Al-4V surface and the thickness and surface roughness of the coating were approximately 150 and 10 μm, respectively. Plasma-sprayed sphene coating on Ti-6Al-4V possessed a significantly improved bonding strength and chemical stability compared with plasma-sprayed hydroxyapatite (HAp) coating. Plasma-sprayed sphene coating supported human osteoblast-like cell (HOB) attachment and significantly enhanced HOB proliferation and differentiation compared with plasma-sprayed HAp coating and uncoated Ti-6Al-4V. Taken together, plasma-sprayed sphene coating on Ti-6Al-4V possessed excellent bonding strength, chemical stability and cellular bioactivity, indicating its potential application for orthopaedic implants. PMID:18664431

Improvement of arthroscopic cartilage stiffness probe using amorphous diamond coating.

PubMed

Töyräs, Juha; Korhonen, Rami K; Voutilainen, Tanja; Jurvelin, Jukka S; Lappalainen, Reijo

2005-04-01

During arthroscopic evaluation of articular cartilage unstable contact and even slipping of the measurement instrument on the tissue surface may degrade the reproducibility of the measurement. The main aim of the present study was to achieve more stable contact by controlling the friction between articular cartilage surface and the arthroscopic cartilage stiffness probe (Artscan 200, Artscan Oy, Helsinki, Finland) using amorphous diamond (AD) coating. In order to obtain surfaces with different average roughnesses (R(a)), polished stainless steel disks were coated with AD by using the filtered pulsed arc-discharge (FPAD) method. Dynamic coefficient of friction (mu) between the articular cartilage (n = 8) and the coated plates along one non-coated plate was then determined. The friction between AD and cartilage could be controlled over a wide range (mu = 0.027-0.728, p < 0.05, Wilcoxon test) by altering the roughness. Possible deterioration of cartilage was investigated by measuring surface roughness after friction tests and comparing it with the roughness of the adjacent, untested samples (n = 8). Importantly, even testing with the roughest AD (R(a) = 1250 nm) did not damage articular surface. On the basis of the friction measurements, a proper AD coating was selected for the stiffness probe. The performance of coated and non-coated probe was compared by measuring bovine osteochondral samples (n = 22) with both instruments. The reproducibility of the stiffness measurements was significantly better with the AD-coated probe (CV% = 4.7) than with the uncoated probe (CV% = 8.2). To conclude, AD coating can be used to safely control dynamic friction with articular surface. Sufficient friction between articular surface and reference plate of the arthroscopic probe improves significantly reproducibility of the stiffness measurements. (c) 2005 Wiley Periodicals, Inc.

Hydrogen absorption induced metal deposition on palladium and palladium-alloy particles

DOEpatents

Wang, Jia X [East Setauket, NY; Adzic, Radoslav R [East Setauket, NY

2009-03-24

The present invention relates to methods for producing metal-coated palladium or palladium-alloy particles. The method includes contacting hydrogen-absorbed palladium or palladium-alloy particles with one or more metal salts to produce a sub-monoatomic or monoatomic metal- or metal-alloy coating on the surface of the hydrogen-absorbed palladium or palladium-alloy particles. The invention also relates to methods for producing catalysts and methods for producing electrical energy using the metal-coated palladium or palladium-alloy particles of the present invention.

Case study of inclined sporadic E layers in the Earth's ionosphere observed by CHAMP/GPS radio occultations: Coupling between the tilted plasma layers and internal waves

NASA Astrophysics Data System (ADS)

Gubenko, Vladimir N.; Pavelyev, A. G.; Kirillovich, I. A.; Liou, Y.-A.

2018-04-01

We have used the radio occultation (RO) satellite data CHAMP/GPS (Challenging Minisatellite Payload/Global Positioning System) for studying the ionosphere of the Earth. A method for deriving the parameters of ionospheric structures is based upon an analysis of the RO signal variations in the phase path and intensity. This method allows one to estimate the spatial displacement of a plasma layer with respect to the ray perigee, and to determine the layer inclination and height correction values. In this paper, we focus on the case study of inclined sporadic E (Es) layers in the high-latitude ionosphere based on available CHAMP RO data. Assuming that the internal gravity waves (IGWs) with the phase-fronts parallel to the ionization layer surfaces are responsible for the tilt angles of sporadic plasma layers, we have developed a new technique for determining the parameters of IGWs linked with the inclined Es structures. A small-scale internal wave may be modulating initially horizontal Es layer in height and causing a direction of the plasma density gradient to be rotated and aligned with that of the wave propagation vector k. The results of determination of the intrinsic wave frequency and period, vertical and horizontal wavelengths, intrinsic vertical and horizontal phase speeds, and other characteristics of IGWs under study are presented and discussed.

Article coated with flash bonded superhydrophobic particles

DOEpatents

Simpson, John T [Clinton, TN; Blue, Craig A [Knoxville, TN; Kiggans, Jr., James O [Oak Ridge, TN

2010-07-13

A method of making article having a superhydrophobic surface includes: providing a solid body defining at least one surface; applying to the surface a plurality of diatomaceous earth particles and/or particles characterized by particle sizes ranging from at least 100 nm to about 10 .mu.m, the particles being further characterized by a plurality of nanopores, wherein at least some of the nanopores provide flow through porosity, the particles being further characterized by a plurality of spaced apart nanostructured features that include a contiguous, protrusive material; flash bonding the particles to the surface so that the particles are adherently bonded to the surface; and applying a hydrophobic coating layer to the surface and the particles so that the hydrophobic coating layer conforms to the nanostructured features.

Iron aluminide alloy coatings and joints, and methods of forming

DOEpatents

Wright, Richard N.; Wright, Julie K.; Moore, Glenn A.

1994-01-01

A method of joining two bodies together, at least one of the bodies being predominantly composed of metal, the two bodies each having a respective joint surface for joining with the joint surface of the other body, the two bodies having a respective melting point, includes the following steps: a) providing aluminum metal and iron metal on at least one of the joint surfaces of the two bodies; b) after providing the aluminum metal and iron metal on the one joint surface, positioning the joint surfaces of the two bodies in juxtaposition against one another with the aluminum and iron positioned therebetween; c) heating the aluminum and iron on the juxtaposed bodies to a temperature from greater than or equal to 600.degree. C. to less than the melting point of the lower melting point body; d) applying pressure on the juxtaposed surfaces; and e) maintaining the pressure and the temperature for a time period effective to form the aluminum and iron into an iron aluminide alloy joint which bonds the juxtaposed surfaces and correspondingly the two bodies together. The method can also effectively be used to coat a body with an iron aluminide coating.

Iron aluminide alloy coatings and joints, and methods of forming

DOEpatents

Wright, R.N.; Wright, J.K.; Moore, G.A.

1994-09-27

Disclosed is a method of joining two bodies together, at least one of the bodies being predominantly composed of metal, the two bodies each having a respective joint surface for joining with the joint surface of the other body, the two bodies having a respective melting point, includes the following steps: (a) providing aluminum metal and iron metal on at least one of the joint surfaces of the two bodies; (b) after providing the aluminum metal and iron metal on the one joint surface, positioning the joint surfaces of the two bodies in juxtaposition against one another with the aluminum and iron positioned therebetween; (c) heating the aluminum and iron on the juxtaposed bodies to a temperature from greater than or equal to 600 C to less than the melting point of the lower melting point body; (d) applying pressure on the juxtaposed surfaces; and (e) maintaining the pressure and the temperature for a time period effective to form the aluminum and iron into an iron aluminide alloy joint which bonds the juxtaposed surfaces and correspondingly the two bodies together. The method can also effectively be used to coat a body with an iron aluminide coating.

Surface modification to waveguides

DOEpatents

Timberlake, John R.; Ruzic, David N.; Moore, Richard L.; Cohen, Samuel A.; Manos, Dennis M.

1983-01-01

A method of treating the interior surfaces of a waveguide to improve power transmission comprising the steps of mechanically polishing to remove surface protrusions; electropolishing to remove embedded particles; ultrasonically cleaning to remove any residue; coating the interior waveguide surfaces with an alkyd resin solution or electrophoretically depositing carbon lamp black suspended in an alkyd resin solution to form a 1.mu. to 5.mu. thick film; vacuum pyrolyzing the film to form a uniform adherent carbon coating.

Tests of the Performance of Coatings for Low Ice Adhesion

NASA Technical Reports Server (NTRS)

Anderson, David N.; Reich, Allen D.

1997-01-01

This paper reports studies of the performance of low-ice-adhesion coatings by NASA Lewis and BFGoodrich. Studies used impact ice accreted both in the NASA Lewis Icing Research Tunnel (IRT) and in the BFGoodrich Icing Wind Tunnel (IWT) and static ice in a BFGoodrich bench-top parallel-plate shear rig. Early tests at NASA Lewis involved simple qualitative evaluations of the ease of removing impact ice from a surface. Coated surfaces were compared with uncoated ones. Some of the coatings were tested again with static ice at BFGoodrich to obtain quantitative measurements. Later, methods to establish the adhesion force on surfaces subjected to impact ice were explored at Lewis. This paper describes the various test programs and the results of testing some of the coatings looked at over the past 5 years. None of the coatings were found to be truly ice-phobic; however, the most effective coatings were found to reduce the adhesion of ice to about 1/2 that of an uncoated aluminum sample.

Coating method for graphite

DOEpatents

Banker, John G.; Holcombe, Jr., Cressie E.

1977-01-01

A method of limiting carbon contamination from graphite ware used in induction melting of uranium alloys is provided comprising coating the graphite surface with a suspension of Y.sub.2 O.sub.3 particles in water containing about 1.5 to 4% by weight sodium carboxymethylcellulose.

Coating method for graphite

DOEpatents

Banker, J.G.; Holcombe, C.E. Jr.

1975-11-06

A method of limiting carbon contamination from graphite ware used in induction melting of uranium alloys is provided. The graphite surface is coated with a suspension of Y/sub 2/O/sub 3/ particles in water containing about 1.5 to 4 percent by weight sodium carboxymethylcellulose.

Bioactivity and biocompatibility of hydroxyapatite-based bioceramic coatings on zirconium by plasma electrolytic oxidation.

PubMed

Aktuğ, Salim Levent; Durdu, Salih; Yalçın, Emine; Çavuşoğlu, Kültigin; Usta, Metin

2017-02-01

In the present work, hydroxyapatite (HAP)-based plasma electrolytic oxide (PEO) coatings were produced on zirconium at different current densities in a solution containing calcium acetate and β-calcium glycerophosphate by a single step. The phase structure, surface morphology, functional groups, thickness and roughness of the coatings were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR), eddy current method and surface profilometer, respectively. The phases of cubic-zirconia, calcium zirconate and HAP were detected by XRD. The amount of HAP and calcium zirconate increased with increasing current density. The surface of the coatings was very porous and rough. Moreover, bioactivity and biocompatibility of the coatings were analyzed in vitro immersion simulated body fluid (SBF) and MTT (3-(4,5-dimethyl thiazol-2yl)-2,5-diphenyl tetrazolium bromide) assay, hemolysis assay and bacterial formation. The apatite-forming ability of the coatings was evaluated after immersion in SBF up to 28days. After immersion, the bioactivity of HAP-based coatings on zirconium was greater than the ones of uncoated zirconium and zirconium oxide-based surface. The bioactivity of PEO surface on zirconium was significantly improved under SBF conditions. The bacterial adhesion of the coatings decreased with increasing current density. The bacterial adhesion of the coating produced at 0.370A/cm 2 was minimum compared to uncoated zirconium coated at 0.260 and 0.292A/cm 2 . The hemocompatibility of HAP-based surfaces was improved by PEO. The cell attachment and proliferation of the PEO coatings were better than the one of uncoated zirconium according to MTT assay results. Copyright © 2016 Elsevier B.V. All rights reserved.

Remanufacture of Zirconium-Based Conversion Coatings on the Surface of Magnesium Alloy

NASA Astrophysics Data System (ADS)

Liu, Zhe; Jin, Guo; Song, Jiahui; Cui, Xiufang; Cai, Zhaobing

2017-04-01

Brush plating provides an effective method for creating a coating on substrates of various shapes. A corroded zirconium-based conversion coating was removed from the surface of a magnesium alloy and then replaced with new coatings prepared via brush plating. The structure and composition of the remanufactured coating were determined via x-ray photoelectron spectroscopy, x-ray diffraction, and Fourier transform infrared spectroscopy. The results revealed that the coatings consist of oxide, fluoride, and tannin-related organics. The composition of the coatings varied with the voltage. Furthermore, as revealed via potentiodynamic polarization spectroscopy, these coatings yielded a significant increase in the corrosion resistance of the magnesium alloy. The friction coefficient remained constant for almost 300s during wear resistance measurements performed under a 1-N load and dry sliding conditions, indicating that the remanufactured coatings provide effective inhibition to corrosion.

The adhesion performance of epoxy coating on AA6063 treated in Ti/Zr/V based solution

NASA Astrophysics Data System (ADS)

Zhu, Wen; Li, Wenfang; Mu, Songlin; Yang, Yunyu; Zuo, Xi

2016-10-01

An environment-friendly titanium/zirconium/vanadium-based (Ti/Zr/V) conversion coating was prepared on aluminum alloy 6063 (AA6063). The epoxy powder coatings were applied on the AA6063 samples with/without Ti/Zr/V conversion coatings via electrostatic spraying. The morphology and composition of the conversion coating were studied by scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The surface free energy components of AA6063 samples were measured by a static contact angle measuring device with Owens method. The adhesion properties of the epoxy coating on AA6063 treated with different conversion times were evaluated using a pull-off tester. The Ti/Zr/V conversion coating was mainly composed of metal oxide (TiO2, ZrO2, V2O5, Al2O3, etc.), metal fluoride (ZrF4, AlF3, etc.) and metal organic complex. The formation time of this conversion coating was reduced to 50 s. After such surface treatment, the samples' surface roughness was increased and the contact angle with water was decreased. Both the surface free energy and the work of adhesion were increased. The adhesion strength between the epoxy coating and AA6063 was enhanced significantly.

Functionalization of Titanium with Chitosan via Silanation: Evaluation of Biological and Mechanical Performances

PubMed Central

Renoud, Pauline; Toury, Bérangère; Benayoun, Stéphane; Attik, Ghania; Grosgogeat, Brigitte

2012-01-01

Complications in dentistry and orthopaedic surgery are mainly induced by peri-implant bacterial infections and current implant devices do not prevent such infections. The coating of antibacterial molecules such as chitosan on its surface would give the implant bioactive properties. The major challenge of this type of coating is the attachment of chitosan to a metal substrate. In this study, we propose to investigate the functionalization of titanium with chitosan via a silanation. Firstly, the surface chemistry and mechanical properties of such coating were evaluated. We also verified if the coated chitosan retained its biocompatibility with the peri-implant cells, as well as its antibacterial properties. FTIR and Tof-SIMS analyses confirmed the presence of chitosan on the titanium surface. This coating showed great scratch resistance and was strongly adhesive to the substrate. These mechanical properties were consistent with an implantology application. The Chitosan-coated surfaces showed strong inhibition of Actinomyces naeslundii growth; they nonetheless showed a non significant inhibition against Porphyromonas gingivalis after 32 hours in liquid media. The chitosan-coating also demonstrated good biocompatibility to NIH3T3 fibroblasts. Thus this method of covalent coating provides a biocompatible material with improved bioactive properties. These results proved that covalent coating of chitosan has significant potential in biomedical device implantation. PMID:22859940

Laminated structures and methods and compositions for producing same

DOEpatents

Fumei, Giancarlo J.; Karabedian, James A.

1977-04-05

Methods for bonding two substrates, one of which is polymeric, which comprise coating the surface of at least one substrate with an adhesive composition comprising a major component which is an adhesive for the first substrate and a minor disperse phase which is a solution of a polymer in a solvent for the polymeric substrate and contacting the coated surface of the one substrate with the surface of the other substrate, together with adhesive compositions useful for joining such substrates, laminates so formed, and articles comprised of such laminates.

Development of AC impedance methods for evaluating corroding metal surfaces and coatings

NASA Technical Reports Server (NTRS)

Knockemus, Ward

1986-01-01

In an effort to investigate metal surface corrosion and the breakdown of metal protective coatings the AC Impedance Method was applied to zinc chromate primer coated 2219-T87 aluminum. The model 368-1 AC Impedance Measurement System recently acquired by the MSFC Corrosion Research Branch was used to monitor changing properties of coated aluminum disks immersed in 3.5% NaCl buffered at ph 5.5 over three to four weeks. The DC polarization resistance runs were performed on the same samples. The corrosion system can be represented by an electronic analog called an equivalent circuit that consists of transistors and capacitors in specific arrangements. This equivalent circuit parallels the impedance behavior of the corrosion system during a frequency scan. Values for resistances and capacities that can be assigned in the equivalent circuit following a least squares analysis of the data describe changes that occur on the corroding metal surface and in the protective coating. A suitable equivalent circuit was determined that predicts the correct Bode phase and magnitude for the experimental sample. The DC corrosion current density data are related to equivalent circuit element parameters.

Electrohydrodynamics in nanochannels coated by mixed polymer brushes: effects of electric field strength and solvent quality

NASA Astrophysics Data System (ADS)

Cao, Qianqian; Tian, Xiu; You, Hao

2018-04-01

We examine the electrohydrodynamics in mixed polymer brush-coated nanochannels and the conformational dynamics of grafted polymers using molecular dynamics simulations. Charged (A) and neutral polymers (B) are alternately grafted on the channel surfaces. The effects of the electric field strength and solvent quality are addressed in detail. The dependence of electroosmotic flow characteristics and polymer conformational behavior on the solvent quality is influenced due to the change of the electric field strength. The enhanced electric field induces a collapse of the neutral polymer chains which adopt a highly extended conformation along the flow direction. However, the thickness of the charged polymer layer is affected weakly by the electric field, and even a slight swelling is identified for the A-B attraction case, implying the conformational coupling between two polymer species. Furthermore, the charged polymer chains incline entirely towards the electric field direction oppositely to the flow direction. More importantly, unlike the neutral polymer chains, the shape factor of the charged polymer chains, which is used to describe the overall shape of polymer chains, is reduced significantly with increasing the electric field strength, corresponding to a more coiled structure.

Fabrication of oriented hydroxyapatite film by RF magnetron sputtering

NASA Astrophysics Data System (ADS)

Hirata, Keishiro; Kubota, Takafumi; Koyama, Daisuke; Takayanagi, Shinji; Matsukawa, Mami

2017-08-01

Hydroxyapatite (HAp) is compatible with bone tissue and is used mainly as a bone prosthetic material, especially as the coating of implants. Oriented HAp film is expected to be a high-quality epitaxial scaffold of the neonatal bone. To fabricate highly oriented HAp thin films via the conventional plasma process, we deposited the HAp film on a Ti coated silica glass substrate using RF magnetron sputtering in low substrate temperature conditions. The X-ray diffraction pattern of the film sample consisted of an intense (002) peak, corresponding to the highly oriented HAp. The (002) peak in XRD diagrams can be attributed either to the monoclinic phase or the hexagonal phase. Pole figure analysis showed that the (002) plane grew parallel to the surface of the substrate, without inclination. Transmission Electron Microscope analysis also showed the fabrication of aligned HAp crystallites. The selected area diffraction patterns indicated the existence of monoclinic phase. The existence of hexagonal phase could not be judged. These results indicate the uniaxial films fabricated by this technique enable to be the epitaxial scaffold of the neonatal bone. This scaffold can be expected to promote connection with the surrounding bone tissue and recovery of the dynamic characteristics of the bone.

Influence of nano alumina coating on the flexural bond strength between zirconia and resin cement

PubMed Central

Mumcu, Emre; Şen, Murat

2018-01-01

PURPOSE The purpose of this in vitro study is to examine the effects of a nano-structured alumina coating on the adhesion between resin cements and zirconia ceramics using a four-point bending test. MATERIALS AND METHODS 100 pairs of zirconium bar specimens were prepared with dimensions of 25 mm × 2 mm × 5 mm and cementation surfaces of 5 mm × 2 mm. The samples were divided into 5 groups of 20 pairs each. The groups are as follows: Group I (C) – Control with no surface modification, Group II (APA) – airborne-particle-abrasion with 110 µm high-purity aluminum oxide (Al2O3) particles, Group III (ROC) – airborne-particle-abrasion with 110 µm silica modified aluminum oxide (Al2O3 + SiO2) particles, Group IV (TCS) – tribochemical silica coated with Al2O3 particles, and Group V (AlC) – nano alumina coating. The surface modifications were assessed on two samples selected from each group by atomic force microscopy and scanning electron microscopy. The samples were cemented with two different self-adhesive resin cements. The bending bond strength was evaluated by mechanical testing. RESULTS According to the ANOVA results, surface treatments, different cement types, and their interactions were statistically significant (P<.05). The highest flexural bond strengths were obtained in nanostructured alumina coated zirconia surfaces (50.4 MPa) and the lowest values were obtained in the control group (12.00 MPa), both of which were cemented using a self-adhesive resin cement. CONCLUSION The surface modifications tested in the current study affected the surface roughness and flexural bond strength of zirconia. The nano alumina coating method significantly increased the flexural bond strength of zirconia ceramics. PMID:29503713

Effect of polymer coating on the osseointegration of CP-Ti dental implant

NASA Astrophysics Data System (ADS)

Al-Hassani, Emad; Al-Hassani, Fatima; Najim, Manar

2018-05-01

Modifications achieved coatings of titanium samples were investigated in order to improve their surface characteristics so as to facilitate bio-integration. Chitosan coating was use for commercial pure Ti alloys manufactured by two different methods in which commercial pure titanium rod converted in form of implant screw by using wire cut machine and lathe, second method included the used of powder technology for producing the implant screws. The coating process of chitosan polymer was carried out using advance technology (electrospnning process) to create fibrous structure from Nano to micro scale of the chitosan on the implant surface which result in a bioactive surface. The characterization includes; microstructure observation, surface chemical composition analysis (EDS), surface roughness (AFM), and the histological analysis. from the SEM No morphological differences were observed among the implants surfaces except for some inconsiderable morphological differences that results from the manufacturing process, by using EDX analysis the surfaces chemical compositions were completely changed and there was large decrease in the percentage of titanium element at the surface which indicates that the surface is covered with chitosan and had a new surface composition and topography. The sample was produced by powder technology process have higher roughness (845.36 nm) than sample produced by machining without any surface treatment (531.7nm),finally The histological view of implant samples after 4weeks of implantation, showed active bone formation in all implant surface which give clear indication of tissue acceptance.

Optically transparent, scratch-resistant, diamond-like carbon coatings

DOEpatents

He, Xiao-Ming; Lee, Deok-Hyung; Nastasi, Michael A.; Walter, Kevin C.; Tuszewski, Michel G.

2003-06-03

A plasma-based method for the deposition of diamond-like carbon (DLC) coatings is described. The process uses a radio-frequency inductively coupled discharge to generate a plasma at relatively low gas pressures. The deposition process is environmentally friendly and scaleable to large areas, and components that have geometrically complicated surfaces can be processed. The method has been used to deposit adherent 100-400 nm thick DLC coatings on metals, glass, and polymers. These coatings are between three and four times harder than steel and are therefore scratch resistant, and transparent to visible light. Boron and silicon doping of the DLC coatings have produced coatings having improved optical properties and lower coating stress levels, but with slightly lower hardness.

The Effect of Composition on the Surface Finish of PS400: A New High Temperature Solid Lubricant Coating

NASA Technical Reports Server (NTRS)

DellaCorte, Christopher; Stanford, malcolm K.; Thomas, Fransua; Edmonds, Brian J.

2010-01-01

A new composite, multi-constituent, solid lubricant coating, NASA PS400, developed for high temperature tribological applications, exhibits a smoother surface finish after grinding and polishing than its predecessors PS200 and PS300. In this paper, the baseline composition of PS400 is modified to investigate each individual constituent s role on the achievable surface finish through a series of coating deposition, grinding, and polishing experiments. Furthermore, to explore the limits of compositional tailoring for improved tribological performance, several PS400 coatings were doped with additional solid lubricants (graphite, MoS2 and BN) and tribologically tested. The test results clearly showed that, compared to PS300 coatings, PS400 achieves a smoother surface finish via a reduced lubricant content. Coatings prepared with higher than the baseline level (10 wt%) of lubricants exhibited higher final surface roughness than the earlier generation PS300 coatings. Reducing or eliminating the one or both lubricants (fluorides or silver) did not further improve the surface finish suggesting that the current composition of PS400 is near optimal with respect to surface finish. Lastly, attempts to improve the poor initial room temperature tribological behavior of PS400 via the addition of traditional solid lubricants were unsuccessful. Based upon this work and earlier results it is expected that future research will concentrate on developing methods to produce a lubricious glaze on the rubbing surface during break in to ensure that low friction and wear are rapidly achieved.

Laser induced heating of coated carbon steel sheets: Consideration of melting and Marangoni flow

NASA Astrophysics Data System (ADS)

Shuja, S. Z.; Yilbas, B. S.

2013-04-01

Laser induced melting of coated carbon steel workpiece is simulated. The coating materials include tungsten carbide, alumina, and boron are incorporated in the simulations. The coating thickness is kept constant at 7.5 μm in the analysis. The enthalpy porosity method is used to account for the phase change in the irradiated region. The study is extended to include the influence of laser intensity transverse mode pattern (β) on the resulting melting characteristics. It is found that peak temperature predicted at the surface is higher for alumina and boron coatings than that of tungsten carbide coating. The influence of the laser intensity transverse mode pattern on the melting characteristics is considerable. Surface temperature predicted agrees with the thermocouple data.

Washing-resistant surfactant coated surface is able to inhibit pathogenic bacteria adhesion

NASA Astrophysics Data System (ADS)

Treter, Janine; Bonatto, Fernando; Krug, Cristiano; Soares, Gabriel Vieira; Baumvol, Israel Jacob Rabin; Macedo, Alexandre José

2014-06-01

Surface-active substances, which are able to organize themselves spontaneously on surfaces, triggering changes in the nature of the solid-liquid interface, are likely to influence microorganism adhesion and biofilm formation. Therefore, this study aimed to evaluate chemical non-ionic surfactants activity against pathogenic microbial biofilms and to cover biomaterial surfaces in order to obtain an anti-infective surface. After testing 11 different surfactants, Pluronic F127 was selected for further studies due to its non-biocidal properties and capability to inhibit up to 90% of biofilm formation of Gram-positive pathogen and its clinical isolates. The coating technique using direct impregnation on the surface showed important antibiofilm formation characteristics, even after extensive washes. Surface roughness and bacterial surface polarity does not influence the adhesion of Staphylococcus epidermidis, however, the material coated surface became extremely hydrophilic. The phenotype of S. epidermidis does not seem to have been affected by the contact with surfactant, reinforcing the evidence that a physical phenomenon is responsible for the activity. This paper presents a simple method of surface coating employing a synthetic surfactant to prevent S. epidermidis biofilm formation.

Optimizing surface characteristics for cell adhesion and proliferation on titanium plasma spray coatings on polyetheretherketone.

PubMed

Yoon, Byung Jo Victor; Xavier, Fred; Walker, Brendon R; Grinberg, Samuel; Cammisa, Frank P; Abjornson, Celeste

2016-10-01

Titanium plasma spray coating on polyetheretherketone (PEEK) is a recent innovation to interbody spacer technology. The inherent hydrophobic properties of standard, uncoated PEEK implants can hamper cell attachment and bone healing during fusion. The addition of titanium coating not only offers initial stability due to increased surface roughness but also long-term stability due to bony ongrowth created from osteoconductive microenvironment on the device surface. The previously established hydrophilic and osteophilic properties of commercially pure titanium (CPTi) can potentially provide an ideal environment promoting cell attachment and bony ongrowth when applied at the end plate level of the fusion site. Because the surface material composition and topography is what seems to directly affect cell adhesion, it is important to determine the ideal titanium coating for the highest effectiveness. The purpose of the study is to determine whether there is an optimal surface roughness for the titanium coatings and whether different polishing methods have a greater effect than roughness or topography in mediating cell adhesion to the surface. The study was divided into two phases. In Phase 1, the effects of varying surface roughnesses on identical polishing method were compared. In Phase 2, the effect of varying polishing methods was compared on identical surface roughnesses. Coating thickness, porosity, and surface roughness were characterized using an optical microscope as per ASTM F 1854 standards. For both phases, PEEK coupons with plasma-sprayed CPTi were used, and human mesenchymal stem cells (hMSCs) at an initial density of 25,000 cells/cm 2 were seeded and cultured for 24 hours before fixation in 10% formalin. The cultured hMSCs were visualized by 4',6-diamidino-2-phenylindole (DAPI) staining, a fluorescent stain that binds to the DNA of living cells. Samples were imaged using an environmental scanning electron microscope (eSEM) (Carl Zeiss Microscopy, Thornwood, NY, USA) using a backscattered detector. Image analysis of the CPTi coatings showed uniform and rough surfaces. For Phase 1, roughness was evaluated as fine, medium, and coarse. The eSEM image analysis and cell counting by DAPI demonstrated that hMSCs have a tendency to form stronger adhesion and greater pseudopodia extensions on fine roughness surfaces. Individual hMSCs were seen forming cytoplasmic processes extending across the width of a pore. There was a 4- and 20-fold reduction in adhered hMSCs with an increase to medium and coarse roughnesses, respectively. For Phase 2, studied groups are (1) medium CPTi coating with zirconia polishing, (2) medium CPTi coating with CPTi polishing, and (3) fine CPTi coating with CPTi polishing. The eSEM image analysis and cell counting by DAPI demonstrated that hMSCs have a tendency to form stronger adhesion and greater pseudopodia extensions on Group 3 over the other two groups. There was a twofold reduction in adhered hMSCs on medium roughness relative to fine. No difference in cell adhesion was found between Groups 1 and 2. Individual hMSCs were seen forming cytoplasmic processes extending across the width of a pore. Previously, it was accepted without much scrutiny that surface coatings were beneficial. This study begins to discover that surface topography directly affects the potential for cells to adhere and proliferate and lead to greater surgical efficacy. Copyright © 2016 Elsevier Inc. All rights reserved.

Composite ceria-coated aerogels and methods of making the same

DOEpatents

Eyring, Edward M; Ernst, Richard D; Turpin, Gregory C; Dunn, Brian C

2013-05-07

Ceria-coated aerogels can include an aerogel support material having a stabilized ceria coating thereon. The ceria coating can be formed by solution or vapor deposition of alcogels or aerogels. Additional catalytic metal species can also be incorporated into the coating to form multi-metallic compounds having improved catalytic activity. Further, the ceria coated aerogels retain high surface areas at elevated temperatures. Thus, improvements in catalytic activity and thermal stability can be achieved using these ceria-coated composite aerogels.

Aqueous processing of composite lithium ion electrode material

DOEpatents

Li, Jianlin; Armstrong, Beth L.; Daniel, Claus; Wood, III, David L.

2017-06-20

A method of making a battery electrode includes the steps of dispersing an active electrode material and a conductive additive in water with at least one dispersant to create a mixed dispersion; treating a surface of a current collector to raise the surface energy of the surface to at least the surface tension of the mixed dispersion; depositing the dispersed active electrode material and conductive additive on a current collector; and heating the coated surface to remove water from the coating.

Aqueous processing of composite lithium ion electrode material

DOEpatents

Li, Jianlin; Armstrong, Beth L; Daniel, Claus; Wood, III, David L

2015-02-17

A method of making a battery electrode includes the steps of dispersing an active electrode material and a conductive additive in water with at least one dispersant to create a mixed dispersion; treating a surface of a current collector to raise the surface energy of the surface to at least the surface tension of the mixed dispersion; depositing the dispersed active electrode material and conductive additive on a current collector; and heating the coated surface to remove water from the coating.

Surface contamination to UV-curable acrylates in the furniture and parquet industry.

PubMed

Surakka, J; Lindh, T; Rosén, G; Fischer, T

2001-03-01

Surface contamination to ultraviolet radiation curable coatings (UV coatings), used increasingly in the parquet and furniture industry, is a matter of concern as a source for skin contamination. UV coatings contain chemically and biologically reactive acrylates, well known as skin contact irritants and sensitizers. Surface contamination may spread secondarily to equipment and other unexpected areas even outside the workplace. Yet, studies concerning this type of contamination are lacking due to lack of suitable sampling methods. Surface contamination of the work environment with risk for skin exposure to UV coating was measured employing a quantitative adhesive tape sampling method developed for this purpose. A pilot study was first performed at three workplaces to evaluate the contamination. In the main study, we wanted to locate and identify in detail the surface contamination of areas where problems exist, and to determine the extent of the problem. Measurements were performed at seven workplaces on two separate workdays (round 1 and 2) within a six-month period. Samples were collected from the workplaces based on the video monitoring of skin contact frequency with the surfaces and categorized into three groups to analyze risk. The pilot study indicated that surface contamination to TPGDA containing UV coatings was common, found in 76 percent of the surfaces, and varied with a maximum of 909 microg TPGDA 10 cm(-2) sampling area. In the main study TPGDA was found in 153 out of 196 collected samples (78.1%); for round one 78.1 percent (82 out of 105 samples) and for round two 78.0 percent (71 out of 91 samples). The average TPGDA mass on positive surface samples was on the first round 2,247 +/- 7,462 microg, and on the second round 2,960 +/- 4,590 microg. We conclude that surface contamination to uncured UV coatings at UV-curing lines is common and this involves a risk for harmful, unintentional skin exposure to acrylates.

Surface-rain interactions: differences in copper runoff for copper sheet of different inclination, orientation, and atmospheric exposure conditions.

PubMed

Hedberg, Yolanda S; Goidanich, Sara; Herting, Gunilla; Wallinder, Inger Odnevall

2015-01-01

Predictions of the diffuse dispersion of metals from outdoor constructions such as roofs and facades are necessary for environmental risk assessment and management. An existing predictive model has been compared with measured data of copper runoff from copper sheets exposed at four different inclinations facing four orientations at two different urban sites (Stockholm, Sweden, and Milan, Italy) during a 4-year period. Its applicability has also been investigated for copper sheet exposed at two marine sites(Cadiz, Spain, for 5 years, and Brest, France, for 9 years). Generally the model can be used for all given conditions. However, vertical surfaces should be considered as surfaces inclined 60-80 due to wind driven effects. The most important parameters that influence copper runoff, and not already included in the model, are the wind and rain characteristics that influence the actual rainfall volume impinging the surface of interest.

Multilayer bioactive glass/zirconium titanate thin films in bone tissue engineering and regenerative dentistry

PubMed Central

Mozafari, Masoud; Salahinejad, Erfan; Shabafrooz, Vahid; Yazdimamaghani, Mostafa; Vashaee, Daryoosh; Tayebi, Lobat

2013-01-01

Surface modification, particularly coatings deposition, is beneficial to tissue-engineering applications. In this work, bioactive glass/zirconium titanate composite thin films were prepared by a sol-gel spin-coating method. The surface features of the coatings were studied by scanning electron microscopy, atomic force microscopy, and spectroscopic reflection analyses. The results show that uniform and sound multilayer thin films were successfully prepared through the optimization of the process variables and the application of carboxymethyl cellulose as a dispersing agent. Also, it was found that the thickness and roughness of the multilayer coatings increase nonlinearly with increasing the number of the layers. This new class of nanocomposite coatings, comprising the bioactive and inert components, is expected not only to enhance bioactivity and biocompatibility, but also to protect the surface of metallic implants against wear and corrosion. PMID:23641155

Numerical study and modeling of the spatial and temporal distribution of the solar field at Khouribga and the 20 Moroccan cities

NASA Astrophysics Data System (ADS)

Nfaoui, M.; El-Hami, K.

2018-02-01

The study or applications of solar energy at a given site are dependent on more complete and detailed data on the solar radiation of this site, the aim of this work is presented the method used in the calculation and describe the available data by trying to extract some useful information. We present the method used in the calculation and describe the available data by trying to extract some useful information. In our study we use programs through MATLAB to estimate the totality of the solar radiation on any inclined surface. Moreover, we will study in the last part the influence of exposure (orientation and inclination) on the amount of solar radiation received on a surface of 1m2. Then in order to study the theoretical solar field available in Khouribga, a series of insolation and irradiation data calculate, and then we apply the same strategy of this work to the 20 Moroccan cities in different time scales (every 3min, every day, every month and all year).

Interface bonding of NiCrAlY coating on laser modified H13 tool steel surface

NASA Astrophysics Data System (ADS)

Reza, M. S.; Aqida, S. N.; Ismail, I.

2016-06-01

Bonding strength of thermal spray coatings depends on the interfacial adhesion between bond coat and substrate material. In this paper, NiCrAlY (Ni-164/211 Ni22 %Cr10 %Al1.0 %Y) coatings were developed on laser modified H13 tool steel surface using atmospheric plasma spray (APS). Different laser peak power, P p, and duty cycle, DC, were investigated in order to improve the mechanical properties of H13 tool steel surface. The APS spraying parameters setting for coatings were set constant. The coating microstructure near the interface was analyzed using IM7000 inverted optical microscope. Interface bonding of NiCrAlY was investigated by interfacial indentation test (IIT) method using MMT-X7 Matsuzawa Hardness Tester Machine with Vickers indenter. Diffusion of atoms along NiCrAlY coating, laser modified and substrate layers was investigated by energy-dispersive X-ray spectroscopy (EDXS) using Hitachi Tabletop Microscope TM3030 Plus. Based on IIT method results, average interfacial toughness, K avg, for reference sample was 2.15 MPa m1/2 compared to sample L1 range of K avg from 6.02 to 6.96 MPa m1/2 and sample L2 range of K avg from 2.47 to 3.46 MPa m1/2. Hence, according to K avg, sample L1 has the highest interface bonding and is being laser modified at lower laser peak power, P p, and higher duty cycle, DC, prior to coating. The EDXS analysis indicated the presence of Fe in the NiCrAlY coating layer and increased Ni and Cr composition in the laser modified layer. Atomic diffusion occurred in both coating and laser modified layers involved in Fe, Ni and Cr elements. These findings introduce enhancement of coating system by substrate surface modification to allow atomic diffusion.

Process system and method for fabricating submicron field emission cathodes

DOEpatents

Jankowski, A.F.; Hayes, J.P.

1998-05-05

A process method and system for making field emission cathodes exists. The deposition source divergence is controlled to produce field emission cathodes with height-to-base aspect ratios that are uniform over large substrate surface areas while using very short source-to-substrate distances. The rate of hole closure is controlled from the cone source. The substrate surface is coated in well defined increments. The deposition source is apertured to coat pixel areas on the substrate. The entire substrate is coated using a manipulator to incrementally move the whole substrate surface past the deposition source. Either collimated sputtering or evaporative deposition sources can be used. The position of the aperture and its size and shape are used to control the field emission cathode size and shape. 3 figs.

Process system and method for fabricating submicron field emission cathodes

DOEpatents

Jankowski, Alan F.; Hayes, Jeffrey P.

1998-01-01

A process method and system for making field emission cathodes exists. The deposition source divergence is controlled to produce field emission cathodes with height-to-base aspect ratios that are uniform over large substrate surface areas while using very short source-to-substrate distances. The rate of hole closure is controlled from the cone source. The substrate surface is coated in well defined increments. The deposition source is apertured to coat pixel areas on the substrate. The entire substrate is coated using a manipulator to incrementally move the whole substrate surface past the deposition source. Either collimated sputtering or evaporative deposition sources can be used. The position of the aperture and its size and shape are used to control the field emission cathode size and shape.

Temperature Mapping of Air Film-Cooled Thermal Barrier Coated Surfaces Using Cr-Doped GdAlO3 Phosphor Thermography

NASA Technical Reports Server (NTRS)

Eldridge, Jeffrey I.; Shyam, Vikram; Wroblewski, Adam C.; Zhu, Dongming; Cuy, Michael D.; Wolfe, Douglas E.

2016-01-01

It has been recently shown that the high luminescence intensity from a Cr-doped GdAlO3 (Cr:GdAlO3) thermographic phosphor enables non-rastered full-field temperature mapping of thermal barrier coating (TBC) surfaces to temperatures above 1000C. In this presentation, temperature mapping by Cr:GdAlO3 based phosphor thermometry of air film-cooled TBC-coated surfaces is demonstrated for both scaled-up cooling hole geometries as well as for actual components in a burner rig test environment. The effects of thermal background radiation and flame chemiluminescence on the measurements are investigated, and advantages of this method over infrared thermography as well as the limitations of this method for studying air film cooling are discussed.

Carbon foam/hydroxyapatite coating for carbon/carbon composites: Microstructure and biocompatibility

NASA Astrophysics Data System (ADS)

Zhang, Leilei; Li, Hejun; Li, Kezhi; Zhang, Shouyang; Lu, Jinhua; Li, Wei; Cao, Sheng; Wang, Bin

2013-12-01

To improve the surface biocompatibility of carbon/carbon composites, a carbon foam/hydroxyapatite coating was applied using a combination method of slurry procedure and ultrasound-assisted electrochemical deposition procedure. The morphology, microstructure and chemical composition of the coating were investigated by scanning electron microscopy, energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and X-ray diffraction. The biocompatibility of the carbon foam/hydroxyapatite coating was investigated by osteoblast-like MG63 cell culture tests. The results showed that the carbon foam could provide a large number of pores on the surface of carbon/carbon composites. The hydroxyapatite crystals could infiltrate into the pores and form the carbon foam/hydroxyapatite coating. The coating covered the carbon/carbon composites fully and uniformly with slice morphology. The cell response tests showed that the MG63 cells on carbon foam/hydroxyapatite coating had a better cell adhesion and cell proliferation than those on uncoated carbon/carbon composites. The carbon foam/hydroxyapatite coatings were cytocompatible and were beneficial to improve the biocompatibility. The approach presented here may be exploited for fabrication of carbon/carbon composite implant surfaces.

Development of YAG:Dy Thermographic Phosphor Coatings for Turbine Engine Applications

NASA Technical Reports Server (NTRS)

Eldridge, J. I.; Jenkins, T. P.; Allison, S. W.; Wolfe, D. E.; Jordan, E. H.

2012-01-01

The selection and development of thermographic phosphor coatings were pursued to meet the objective of demonstrating luminescence-decay-based temperature measurements up to 1300C on the surface of a vane in an operating demonstrator turbine engine. To meet this objective, YAG:Dy was selected based on the desirable luminescence performance observed for YAG:Dy powder: (1) excellent temperature sensitivity and intensity at operating turbine engine temperatures, (2) an emission peak at the relatively short wavelength of 456 nm, where the interference from background blackbody radiation is fairly low, and (3) its nearly single exponential decay which makes for a simple, reliable temperature calibration. However, implementation of YAG:Dy for surface temperature measurements required application of YAG:Dy as a coating onto the surface of a superalloy component with a preexisting yttria-stabilized zirconia (YSZ) thermal barrier coating (TBC). An inherent dilemma in producing a YAG:Dy coating is that coating processing is constrained to be performed at temperatures below (less than 1200C) what is considered safe for the superalloy component, much lower than temperatures used to produce the high quality crystalline powder. Therefore, YAG:Dy coatings tend to exhibit lower luminescence performance compared to well prepared YAG:Dy powder, and the luminescence performance of the coating will depend on the method of coating deposition. In this presentation, the luminescence performance of YAG:Dy coatings prepared by the different methods of (1) application of a binder-based YAG:Dy-containing paint, (2) solution precursor plasma spray (SPPS), and (3) electron-beam physical vapor deposition (EB-PVD) and the effect of post-deposition heat treatments will be discussed.

Study of microtip-based extraction and purification of DNA from human samples for portable devices

NASA Astrophysics Data System (ADS)

Fotouhi, Gareth

DNA sample preparation is essential for genetic analysis. However, rapid and easy-to-use methods are a major challenge to obtaining genetic information. Furthermore, DNA sample preparation technology must follow the growing need for point-of-care (POC) diagnostics. The current use of centrifuges, large robots, and laboratory-intensive protocols has to be minimized to meet the global challenge of limited access healthcare by bringing the lab to patients through POC devices. To address these challenges, a novel extraction method of genomic DNA from human samples is presented by using heat-cured polyethyleneimine-coated microtips generating a high electric field. The microtip extraction method is based on recent work using an electric field and capillary action integrated into an automated device. The main challenges to the method are: (1) to obtain a stable microtip surface for the controlled capture and release of DNA and (2) to improve the recovery of DNA from samples with a high concentration of inhibitors, such as human samples. The present study addresses these challenges by investigating the heat curing of polyethyleneimine (PEI) coated on the surface of the microtip. Heat-cured PEI-coated microtips are shown to control the capture and release of DNA. Protocols are developed for the extraction and purification of DNA from human samples. Heat-cured PEI-coated microtip methods of DNA sample preparation are used to extract genomic DNA from human samples. It is discovered through experiment that heat curing of a PEI layer on a gold-coated surface below 150°C could inhibit the signal of polymerase chain reaction (PCR). Below 150°C, the PEI layer is not completely cured and dissolved off the gold-coated surface. Dissolved PEI binds with DNA to inhibit PCR. Heat curing of a PEI layer above 150°C on a gold-coated surface prevents inhibition to PCR and gel electrophoresis. In comparison to gold-coated microtips, the 225°C-cured PEI-coated microtips improve the recovery of DNA to 45% efficiency. Furthermore, the 225°C-cured PEI-coated microtips recover more DNA than gold-coated microtips when the surface is washed. Heat-cured (225°C) PEI-coated microtips are used for the recovery of human genomic DNA from whole blood. A washing protocol is developed to remove inhibiting particles bound to the PEI-coated microtip surface after DNA extraction. From 1.25 muL of whole blood, an average of 1.83 ng of human genomic DNA is captured, purified, and released using a 225°C-cured PEI-coated microtip in less than 30 minutes. The extracted DNA is profiled by short tandem repeat analysis (STR). For forensic and medical applications, genomic DNA is extracted from dried samples using heat-cured PEI-coated microtips that are integrated into an automated device. DNA extraction from dried samples is critical for forensics. The use of dried samples in the medical field is increasing because dried samples are convenient for storage, biosafety, and contamination. The main challenge is the time required to properly extract DNA in a purified form. Typically, a 1 hour incubation period is required to complete this process. Overnight incubation is sometimes necessary. To address this challenge, a pre-extraction washing step is investigated to remove inhibiting particles from dried blood spots (DBS) before DNA is released from dried form into solution for microtip extraction. The developed protocol is expanded to extract DNA from a variety of dried samples including nasal swabs, buccal swabs, and other forensic samples. In comparison to a commercial kit, the microtip-based extraction reduced the processing time from 1.5 hours to 30 minutes or less with an equivalent concentration of extracted DNA from dried blood spots. The developed assay will benefit genetic studies on newborn screening, forensic investigation, and POC diagnostics.

Improving thermal and electrochemical performances of LiCoO{sub 2} cathode at high cut-off charge potentials by MF{sub 3} (M=Ce, Al) coating

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

Aboulaich, Abdelmaula, E-mail: a.aboulaich@managemgroup.com; Ouzaouit, Khalid; Faqir, Hakim

2016-01-15

Highlights: • Fluoride metal is successfully coated on the surface of LiCoO{sub 2}. • Easy and scalable method is adopted for the synthesis of coated-LiCoO{sub 2}. • Appropriate amount of AlF{sub 3} or CeF{sub 3} is beneficial to reduce cation disorder. • The electrochemical performances of coated LiCoO{sub 2} is significantly enhanced at higher potential (cycling efficiency and reversible capacity). • The coated cathode exhibits excellent thermal stability highlighted by calorimetric technique. - Abstract: Surface coating of LiCoO{sub 2} remained one of the efficient methods to enhance its electrochemical and thermal performances, especially at high cut-off potential. In this work,more » MF{sub 3} (M = Ce, Al) coated LiCoO{sub 2} was synthesized via co-precipitation method followed by a solid state reaction at 400 °C. The morphology and structure of the modified cathode material were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the fluoride compound MF{sub 3} is successfully coated on the surface of LiCoO{sub 2} cathode particles with an average layer thickness about 12 nm and 40 nm for AlF{sub 3} and CeF{sub 3}, respectively. The electrochemical tests show that the AlF{sub 3}-coating layer significantly enhances the cycling performance of LiCoO{sub 2} cathode material, even at high cut-off potential. While the bare LiCoO{sub 2} cathode displays fast fading at 4.6 V vs. Li{sup +}/Li cutoff potential, the surface-modified electrode exhibits the great capacity of 160 mAh g{sup −1} with excellent capacity retention on several cycles. We concluded that the electrochemical and the thermal enhancement at high potential are ascribed to the presence of MF{sub 3} coating layer which prevent the side reaction during the charge discharge process, alleviate the attack by the acidic electrolyte and reduce the damage of electrode structure.« less

Nanoparticle coating of a microchannel surface is an effective method for increasing the critical heat flux

NASA Astrophysics Data System (ADS)

Shustov, M. V.; Kuzma-Kichta, Yu. A.; Lavrikov, A. V.

2017-04-01

Results are presented of an investigation into water boiling in a single microchannel 0.2 mm high, 3 mm wide, and 13.7 mm long with a smooth heating surface or with a coating from aluminum oxide nanoparticles. The experimental procedure and the test setup are described. The top wall of the microchannel is made of glass so that video recording in the reflected light of the process can be made. A coating of Al2O3 particles is applied onto the heating surface before the experiments using a method developed by the authors of the paper. The experiments yielded data on heat transfer and void fraction and its fluctuations for the bubble and transient boiling in the microchannel. The dependence was established of the heat flux on the temperature of the microchannel wall with a smooth surface or a surface with Al2O3 nanoparticle coating for various mass flows in the microchannel. The boiling crisis has been found to occur in the microchannel with a nanoparticle coating at a considerably higher heat flux than that in the channel without coating. The experimental data also suggest that the nanoparticle coating improves heat transfer in the transition boiling region. Processing of the data obtained using a high-speed video revealed void fraction fluctuations enabling us to describe two-phase flow regimes with the flow boiling in a microchannel. It has been found that a return flow occurs in the microchannel under certain conditions. A hypothesis for its causes is proposed. The dependence of the void fraction on the steam quality in the microchannel with or without a nanoparticle coating was determined from the video records. The experimental data on void fraction for boiling in the microchannel without coating are approximated by an empirical correlation. The experiments demonstrate that the void fraction during boiling in the microchannel with a nanoparticle coating is higher than during boiling in the channel without coating (where φ and x are the void fraction and the steam quality, respectively) in the region of a sharp increase in the φ( x) curve.

Polymer network/carbon layer on monolith support and monolith catalytic reactor

DOEpatents

Nordquist, Andrew Francis; Wilhelm, Frederick Carl; Waller, Francis Joseph; Machado, Reinaldo Mario

2003-08-26

The present invention relates to an improved monolith catalytic reactor and a monolith support. The improvement in the support resides in a polymer network/carbon coating applied to the surface of a porous substrate and a catalytic metal, preferably a transition metal catalyst applied to the surface of the polymer network/carbon coating. The monolith support has from 100 to 800 cells per square inch and a polymer network/carbon coating with surface area of from 0.1 to 15 m.sup.2 /gram as measured by adsorption of N.sub.2 or Kr using the BET method.

The formation of FHA coating on biodegradable Mg-Zn-Zr alloy using a two-step chemical treatment method

NASA Astrophysics Data System (ADS)

Jiang, S. T.; Zhang, J.; Shun, S. Z.; Chen, M. F.

2016-12-01

To improve the corrosion resistance of the biomedical magnesium alloy, a two-step chemical treatment method has been employed to prepare an FHA coating on the alloy surface. Prior to forming an FHA layer, the samples of Mg-3 wt% Zn-0.5 wt% Zr alloy were soaked in HF with concentration of 20% (v/v) at 37 °C temperature for 2 h, and were then placed into an aqueous solution with 0.1 mol/L Ca(NO3).4H2O and 0.06 mol/L NH4H2PO4 at 90 °C to prepare the Ca-P coating. The concentrations of Mg2+, F- ions, and pH variation with immersing time in the solution were investigated to explore the growth mechanism of FHA. The surface morphologies and compositions of the coatings were characterized by X-ray diffraction, scanning electron microscopy, and energy dispersive spectroscopy. The results showed that the alloy surface treated with acid formed a layer of MgF2 nanoparticles with a thickness of 0.7 μm. The corrosion resistance of coatings in SBF solution was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization. The results showed that the substrate with FHA coating had good corrosion resistance. After immersing into the calcium phosphate solution, some small spherical particles were first formed on the surface; these then cover the surface completely after 20 min. Some clusters consisting of needle-like crystal were observed in the spherical particles covering the surface, and the Ca/P ratio of the needle-like crystal was 1.46, clearly growing along the c axis preferred orientation growth. After immersion for 60 min, the FHA coating with completely uniform growth was obtained on the Mg-Zn-Zr alloy surface with its thickness reaching about 120 μm.

Method of fabricating silicon carbide coatings on graphite surfaces

DOEpatents

Varacalle, D.J. Jr.; Herman, H.; Burchell, T.D.

1994-07-26

The vacuum plasma spray process produces well-bonded, dense, stress-free coatings for a variety of materials on a wide range of substrates. The process is used in many industries to provide for the excellent wear, corrosion resistance, and high temperature behavior of the fabricated coatings. In this application, silicon metal is deposited on graphite. This invention discloses the optimum processing parameters for as-sprayed coating qualities. The method also discloses the effect of thermal cycling on silicon samples in an inert helium atmosphere at about 1,600 C which transforms the coating to silicon carbide. 3 figs.

Method of fabricating silicon carbide coatings on graphite surfaces

DOEpatents

Varacalle, Jr., Dominic J.; Herman, Herbert; Burchell, Timothy D.

1994-01-01

The vacuum plasma spray process produces well-bonded, dense, stress-free coatings for a variety of materials on a wide range of substrates. The process is used in many industries to provide for the excellent wear, corrosion resistance, and high temperature behavior of the fabricated coatings. In this application, silicon metal is deposited on graphite. This invention discloses the optimum processing parameters for as-sprayed coating qualities. The method also discloses the effect of thermal cycling on silicon samples in an inert helium atmosphere at about 1600.degree.C. which transforms the coating to silicon carbide.

A Scale-up Approach for Film Coating Process Based on Surface Roughness as the Critical Quality Attribute.

PubMed

Yoshino, Hiroyuki; Hara, Yuko; Dohi, Masafumi; Yamashita, Kazunari; Hakomori, Tadashi; Kimura, Shin-Ichiro; Iwao, Yasunori; Itai, Shigeru

2018-04-01

Scale-up approaches for film coating process have been established for each type of film coating equipment from thermodynamic and mechanical analyses for several decades. The objective of the present study was to establish a versatile scale-up approach for film coating process applicable to commercial production that is based on critical quality attribute (CQA) using the Quality by Design (QbD) approach and is independent of the equipment used. Experiments on a pilot scale using the Design of Experiment (DoE) approach were performed to find a suitable CQA from surface roughness, contact angle, color difference, and coating film properties by terahertz spectroscopy. Surface roughness was determined to be a suitable CQA from a quantitative appearance evaluation. When surface roughness was fixed as the CQA, the water content of the film-coated tablets was determined to be the critical material attribute (CMA), a parameter that does not depend on scale or equipment. Finally, to verify the scale-up approach determined from the pilot scale, experiments on a commercial scale were performed. The good correlation between the surface roughness (CQA) and the water content (CMA) identified at the pilot scale was also retained at the commercial scale, indicating that our proposed method should be useful as a scale-up approach for film coating process.

Surface Modification of SiO2 Microchannels with Biocompatible Polymer Using Supercritical Carbon Dioxide

NASA Astrophysics Data System (ADS)

Saito, Tatsuro; Momose, Takeshi; Hoshi, Toru; Takai, Madoka; Ishihara, Kazuhiko; Shimogaki, Yukihiro

2010-11-01

The surface of 500-mm-long microchannels in SiO2 microchips was modified using supercritical CO2 (scCO2) and a biocompatible polymer was coated on it to confer biocompatibility to the SiO2 surface. In this method, the SiO2 surface of a microchannel was coated with poly(ethylene glycol monomethacrylate) (PEGMA) as the biocompatible polymer using allyltriethoxysilane (ATES) as the anchor material in scCO2 as the reactive medium. Results were compared with those using the conventional wet method. The surface of a microchannel could not be modified by the wet method owing to the surface tension and viscosity of the liquid, but it was modified uniformly by the scCO2 method probably owing to the near-zero surface tension, low viscosity, and high diffusivity of scCO2. The effect of the surface modification by the scCO2 method to prevent the adsorption of protein was as high as that of the modification by the wet method. Modified microchips can be used in biochemical and medical analyses.

Surface modification to waveguides

DOEpatents

Timberlake, J.R.; Ruzic, D.N.; Moore, R.L.; Cohen, S.A.; Manos, D.M.

1982-06-16

A method is described for treating the interior surfaces of a waveguide to improve power transmission comprising the steps of mechanically polishing to remove surface protrusions; electropolishing to remove embedded particles; ultrasonically cleaning to remove any residue; coating the interior waveguide surfaces with an alkyd resin solution or electrophoretically depositing carbon lamp black suspended in an alkyd resin solution to form a 1..mu.. to 5..mu.. thick film; vacuum pyrolyzing the film to form a uniform adherent carbon coating.

Corrosion Behavior of PEO Coatings Formed on AZ31 Alloy in Phosphate-Based Electrolytes with Calcium Acetate Additive

NASA Astrophysics Data System (ADS)

Ziyaei, E.; Atapour, M.; Edris, H.; Hakimizad, A.

2017-07-01

The PEO coating started on magnesium AZ31 using a unipolar DC power source. The coating was generated in the electrolyte based on Na3PO4·12H2O and KOH with calcium acetate as additive. The x-ray diffraction method showed some phases containing calcium and phosphate, which was created in the presence of additive. Also, the EDS tests of the sample's surfaces proved the existence of calcium on the surface. Based on the electrochemical tests results, the most corrosion resistance belongs to the sample with calcium acetate additive. In fact, the results of the EIS tests showed the coating with calcium acetate has the highest resistance but the lowest capacitance. However, this state belongs to the surface morphology, the lower porosity, and surface chemical composition.

Electrochemical surface modification of titanium in dentistry.

PubMed

Kim, Kyo-Han; Ramaswamy, Narayanan

2009-01-01

Titanium and its alloys have good biocompatibility with body cells and tissues and are widely used for implant applications. However, clinical procedures place more stringent and tough requirements on the titanium surface necessitating artificial surface treatments. Among the many methods of titanium surface modification, electrochemical techniques are simple and cheap. Anodic oxidation is the anodic electrochemical technique while electrophoretic and cathodic depositions are the cathodic electrochemical techniques. By anodic oxidation it is possible to obtain desired roughness, porosity and chemical composition of the oxide. Anodic oxidation at high voltages can improve the crystallinity of the oxide. The chief advantage of this technique is doping of the coating of the bath constituents and incorporation of these elements improves the properties of the oxide. Electrophoretic deposition uses hydroxyapatite (HA) powders dispersed in a suitable solvent at a particular pH. Under these operating conditions these particles acquire positive charge and coatings are obtained on the cathodic titanium by applying an external electric field. These coatings require a post-sintering treatment to improve the coating properties. Cathodic deposition is another type of electrochemical method where HA is formed in situ from an electrolyte containing calcium and phosphate ions. It is also possible to alter structure and/or chemistry of the obtained deposit. Nano-grained HA has higher surface energy and greater biological activity and therefore emphasis is being laid to produce these coatings by cathodic deposition.

Dip coating of sol-gels

NASA Astrophysics Data System (ADS)

Schunk, P. R.; Hurd, A. J.; Brinker, C. J.

Dip coating is the primary means of depositing sol-gel films for precision optical coatings. Sols are typically multicomponent systems consisting of an inorganic phase dispersed in a solvent mixture, with each component differing in volatility and surface tension. This, together with slow coating speeds (less than 1cm/s), makes analysis of the coating process complicated; unlike most high-speed coating methods, solvent evaporation, evolving rheology, and surface tension gradients alter significantly the fluid mechanics of the deposition stage. These phenomena were studied with computer-aided predictions of the flow and species transport fields. The underlying theory involves mass, momentum, and species transport on a domain of unknown shape, with models and constitutive equations for vapor-liquid equilibria and surface tension. Due accounting is made for the unknown position of the free surface, which locates according to the capillary hydrodynamic forces and solvent loss by evaporation. Predictions of the effects of mass transfer, hydrodynamics, and surface tension gradients on final film thickness are compared with ellipsometry measurements of film thickness on a laboratory pilot coater. Although quantitative agreement is still lacking, both experiment and theory reveal that the film profile near the drying line takes on a parabolic shape.

Osteogenic Responses to Zirconia with Hydroxyapatite Coating by Aerosol Deposition

PubMed Central

Cho, Y.; Hong, J.; Ryoo, H.; Kim, D.; Park, J.

2015-01-01

Previously, we found that osteogenic responses to zirconia co-doped with niobium oxide (Nb2O5) or tantalum oxide (Ta2O5) are comparable with responses to titanium, which is widely used as a dental implant material. The present study aimed to evaluate the in vitro osteogenic potential of hydroxyapatite (HA)-coated zirconia by an aerosol deposition method for improved osseointegration. Surface analysis by scanning electron microscopy and x-ray diffraction proved that a thin as-deposited HA film on zirconia showed a shallow, regular, crater-like surface. Deposition of dense and uniform HA films was measured by SEM, and the contact angle test demonstrated improved wettability of the HA-coated surface. Confocal laser scanning microscopy indicated that MC3T3-E1 pre-osteoblast attachment did not differ notably between the titanium and zirconia surfaces; however, cells on the HA-coated zirconia exhibited a lower proliferation than those on the uncoated zirconia late in the culture. Nevertheless, ALP, alizarin red S staining, and bone marker gene expression analysis indicated good osteogenic responses on HA-coated zirconia. Our results suggest that HA-coating by aerosol deposition improves the quality of surface modification and is favorable to osteogenesis. PMID:25586588

Sandblasting and silica-coating of dental alloys: volume loss, morphology and changes in the surface composition.

PubMed

Kern, M; Thompson, V P

1993-05-01

Silica-coating alloys improves chemo-mechanical bonding. Sandblasting is recommended as pretreatment to thermal silica-coating or as part of a tribochemical silica-coating process. This study evaluated the effects of sandblasting and coating techniques on volume loss, surface morphology and compositional changes in noble (AuAgCu) and base alloys (NiCr and CoCr). Volume loss was statistically significantly higher in the noble as compared to the base alloys but does not seem to be critical for the clinical fit of restorations. Embedded alumina particles were found in all alloys after sandblasting and the alumina content increased to a range of 14 to 37 wt% as measured by EDS. Following tribochemical silica-coating, a layer of small silica particles remained on the surface, increasing the silica content to between 12 and 20 wt%. Ultrasonic cleaning removed loose alumina or silica particles from the surface, resulting in only slight decreases in alumina or silica contents, thus suggesting firm attachment of the major part of alumina and silica to the alloy surface. Clinically, ultrasonic cleaning of sandblasted and tribochemically silica-coated alloys might improve resin bonding as loose surface particles are removed without relevant changes in composition. Silica content following thermal silica-coating treatment increased only slightly from the sandblasted specimen. The silica layer employed by these silica-coating methods differs widely in both morphology and thickness. These results provide a basis for explanation of adhesive failure modes in bond strength tests which will possibly optimize resin bonding. Further research is needed to characterize the outermost surface layers after these treatments and the exact location of adhesive failures.

Solvent effect on polystyrene surface roughness on top of QCM sensor

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

Sakti, Setyawan P., E-mail: sakti@ub.ac.id; Rahmawati, Eka; Robiandi, Fadli

2016-03-11

Quartz Crystal Microbalance (QCM) has been used as a basis for many chemical sensors and biosensor. Its sensitivity to mass change which can detect a mass change on its surface down to sub ng/cm2 is one of its interesting aspects. Another interesting feature is its ability to work in liquid environment. However, there are many aspects which influence QCM sensor properties in contact with liquid. One of the aspects is surface roughness of the matrix layer where on top of it a biological sensitive layer will be immobilized. One of matrix layers in the immobilizing biological sensitive layer was polystyrene.more » Polystyrene was coated on the QCM sensor by using the spin coating method. During the coating process, polystyrene was solved using non-polar solvent. It is known that the physical and chemical properties of the solvent affect a transition process from soluble polymer becoming rigid polymer layer. In this work, we show that polystyrene solved in chloroform has a higher surface roughness compare to one solved in toluene, xylene, or tetrahydrofuran. Surface roughness of the polystyrene coating were measured using a non-contact profilometer. However, we also found that there is no difference on the electrical impedance of the QCM sensor coated with polystyrene resulted from differing solvent when the sensor was in contact with air and water. Thus, all of the mentioned solvent can be used to solve the polystyrene as a coating material for QCM sensor without affecting the electrical performance of the sensor, but the choice of the solution can be used as a simple method to control the difference roughness of the polystyrene coating.« less

Solvent effect on polystyrene surface roughness on top of QCM sensor

NASA Astrophysics Data System (ADS)

Sakti, Setyawan P.; Rahmawati, Eka; Robiandi, Fadli

2016-03-01

Quartz Crystal Microbalance (QCM) has been used as a basis for many chemical sensors and biosensor. Its sensitivity to mass change which can detect a mass change on its surface down to sub ng/cm2 is one of its interesting aspects. Another interesting feature is its ability to work in liquid environment. However, there are many aspects which influence QCM sensor properties in contact with liquid. One of the aspects is surface roughness of the matrix layer where on top of it a biological sensitive layer will be immobilized. One of matrix layers in the immobilizing biological sensitive layer was polystyrene. Polystyrene was coated on the QCM sensor by using the spin coating method. During the coating process, polystyrene was solved using non-polar solvent. It is known that the physical and chemical properties of the solvent affect a transition process from soluble polymer becoming rigid polymer layer. In this work, we show that polystyrene solved in chloroform has a higher surface roughness compare to one solved in toluene, xylene, or tetrahydrofuran. Surface roughness of the polystyrene coating were measured using a non-contact profilometer. However, we also found that there is no difference on the electrical impedance of the QCM sensor coated with polystyrene resulted from differing solvent when the sensor was in contact with air and water. Thus, all of the mentioned solvent can be used to solve the polystyrene as a coating material for QCM sensor without affecting the electrical performance of the sensor, but the choice of the solution can be used as a simple method to control the difference roughness of the polystyrene coating.

Li3PO4 surface coating on Ni-rich LiNi0.6Co0.2Mn0.2O2 by a citric acid assisted sol-gel method: Improved thermal stability and high-voltage performance

NASA Astrophysics Data System (ADS)

Lee, Suk-Woo; Kim, Myeong-Seong; Jeong, Jun Hui; Kim, Dong-Hyun; Chung, Kyung Yoon; Roh, Kwang Chul; Kim, Kwang-Bum

2017-08-01

A surface coating of Li3PO4 was applied to a Ni-rich LiNi0.6Co0.2Mn0.2O2 (NCM) material to improve its thermal stability and electrochemical properties via a citric acid assisted sol-gel method. The addition of citric acid effectively suppressed the instant formation of Li3PO4 in solution, resulting in successful coating of the NCM surface. The improved thermal stability of NCM after Li3PO4 surface coating was demonstrated by differential scanning calorimetry (DSC) analysis and in situ time-resolved X-ray diffraction (TR-XRD). In particular, the TR-XRD results showed that the improved thermal stability after Li3PO4 surface coating originates from suppression of the phase transition of charged NCM at high temperatures. Furthermore, the charge-discharge tests demonstrated that Li3PO4-coated LiNi0.6Co0.2Mn0.2O2 (LP-NCM) has excellent electrochemical properties. LP-NCM exhibited a specific capacity of 192.7 mAh g-1, a capacity retention of 44.1% at 10 C, and a capacity retention of 79.7% after 100 cycles at a high cut-off voltage of 4.7 V; these values represent remarkably improved electrochemical properties compared with those of bare NCM. These improved thermal and electrochemical properties were mainly attributed to the improvement of the structural stability of the material and the suppression of the interface reaction between the cathode and the electrolyte owing to the Li3PO4 coating.

Corrosion of Nickel-Titanium Orthodontic Archwires in Saliva and Oral Probiotic Supplements

PubMed Central

Turco, Gianluca; Contardo, Luca; Serdarević, Nikolina Leona; Otmačić, Helena; Ćurković; Špalj, Stjepan

2017-01-01

Objectives The aim of the study was to examine how probiotic supplements affect the corrosion stability of orthodontic archwires made of nickel-titanium alloy (NiTi). Materials and Methods NiTi archwires (0.508x0.508 and having the length of 2.5 cm) were tested. The archwires (composition Ni=50.4%, Ti=49.6%) were uncoated, nitrified and rhodium coated. Surface microgeometry was observed by using scanning electron microscope and surface roughness was measured by profilometer through these variables: roughness average, maximum height and maximum roughness depth. Corrosion was examined by electrochemical method of cyclic polarisation. Results Rhodium coated alloy in saliva has significantly higher general corrosion in saliva than nitrified alloy and uncoated alloy, with large effect size (p=0.027; η2=0.700). In the presence of probiotics, the result was even more pronounced (p<0.001; η2=0.936). Probiotic supplement increases general and localised corrosion of rhodium coated archwire and slightly decreases general corrosion and increases localised corrosion in uncoated archwire, while in the case of nitrified archwire the probability of corrosion is very low. The differences in surface roughness between NiTi wires before corrosion are not significant. Exposure to saliva decreases roughness average in rhodium coated wire (p=0.015; η2=0.501). Media do not significantly influence surface microgeometry in nitrified and uncoated wires. Conclusion Probiotic supplement affects corrosion depending on the type of coating of the NiTi archwire. It increases general corrosion of rhodium coated wire and causes localised corrosion of uncoated and rhodium coated archwire. Probiotic supplement does not have greater influence on surface roughness compared to that of saliva. PMID:29872237

Electrochemical Characteristics of Cell Cultured Ti-Nb-Zr Alloys After Nano-Crystallized Si-HA Coating.

PubMed

Jeong, Yong-Hoon; Choe, Han-Cheol

2015-01-01

The aim of this study was to investigate the electrochemical characteristics of nano crystallized Si-HA coating on Ti-Nb-Zr alloy after human osteoblast like (HOB) cell attachment. The Ti-Nb-Zr alloy was manufactured with 35 wt.% of Nb and 10 wt.% of Zr by arc melting furnace to appropriate physical properties as biomaterials. The HA and Si-substituted coatings were prepared by electron-beam physical vapor deposition method with 0.5, 0.8 and 1.2 wt.% of Si contents, and nano aging treatment was performed 500 degrees C for 1 h. The characteristics of coating surface were analyzed by field emission scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction, respectively. To evaluate of cell attachment on cell cultured surface, the potentiodynamic test was performed on the surface using HOB cells. The results showed that the Si-HA coating surface showed higher tendency of cell attachment than that of single HA coating, corrosion resistance value was increased by dense of cell attachment.

Structure, composition and morphology of bioactive titanate layer on porous titanium surfaces

NASA Astrophysics Data System (ADS)

Li, Jinshan; Wang, Xiaohua; Hu, Rui; Kou, Hongchao

2014-07-01

A bioactive coating was produced on pore surfaces of porous titanium samples by an amendatory alkali-heat treatment method. Porous titanium was prepared by powder metallurgy and its porosity and average size were 45% and 135 μm, respectively. Coating morphology, coating structure and phase constituents were examined by SEM, XPS and XRD. It was found that a micro-network structure with sizes of <200 nm mainly composed of bioactive sodium titanate and rutile phases of TiO2 covered the interior and exterior of porous titanium cells, and redundant Ca ion was detected in the titanate layer. The concentration distribution of Ti, O, Ca and Na in the coating showed a compositional gradient from the intermediate layer toward the outer surface. These compositional gradients indicate that the coating bonded to Ti substrate without a distinct interface. After immersion into the SBF solution for 3 days, a bone-like carbonate-hydroxylapatite showing a good biocompatibility was detected on the coating surface. And the redundant Ca advanced the bioactivity of the coating. Thus, the present modification is expected to allow the use of the bioactive porous titanium as artificial bones even under load-bearing conditions.

Formation mechanism and adhesive strength of a hydroxyapatite/TiO2 composite coating on a titanium surface prepared by micro-arc oxidation

NASA Astrophysics Data System (ADS)

Liu, Shimin; Li, Baoe; Liang, Chunyong; Wang, Hongshui; Qiao, Zhixia

2016-01-01

A hydroxyapatite (HA)/TiO2 composite coating was prepared on a titanium surface by one-step micro-arc oxidation (MAO). The formation mechanism of the composite coating was investigated and the adhesion of the coating to the substrate was also measured. The results showed that flocculent structures could be obtained during the early stages of treatment. As the treatment period extended, increasing amounts of Ca-P precipitate appeared on the surface, and the flocculent morphology transformed into a plate-like morphology. Then the plate-like calcium and phosphate salt self-assembled to form flower-like apatite. The Ca/P atomic ratio gradually decreased, indicating that the amounts of Ca2+ ions which diffused into the coating decreased more rapidly than that of PO43- or HPO42-. The adhesive strength between the apatite and TiO2 coating was improved. This improvement is attributed to the interlocking effect between the apatite and TiO2 layer which formed simultaneously during the early stages of the one-step MAO. This study shows that it is a promising method to prepare bioactive coating on a titanium surface.

Electrochemical properties of Sn-based nanopowders synthesized by a pulsed wire evaporation method and effect of binder coating

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

Ha, Jong-Keun; Song, Ju-Seok; Cho, Gyu-Bong

Highlights: • Sn-based nanoparticles are fabricated by using the pulsed wire evaporation method. • The electrodes are prepared by mixing the graphene and coating the surface. • Coating the surface of electrode is used with brushing of simple and facile method. • The electrochemical measurements are performed with galvanostatic experiments. • The coating electrode maintains capacity nearly of 501 mAh g{sup −1} up to 100 cycles. - Abstract: Sn-based nanoparticles are prepared with the O{sub 2} concentrations in chamber of Ar atmosphere (by v/v) by using the pulsed wire evaporation (PWE) method. The prepared electrodes are only Sn-based powder electrode,more » its binder coating electrode and Sn-based powder/graphene nanocomposite electrode. Morphology and structure of the synthesized powders and electrodes are investigated with a field emission scanning electron microscope (FE-SEM) and an X-ray diffraction (XRD) analysis. The electrochemical measurements were performed with galvanostatic cycling experiments using a coin type cell of CR2032 (Ø20, T3.2 mm). The binder coating electrode is superior to others and maintains delithiation capacity nearly of 501 mAh g{sup −1} as 58.3% of first delithiation capacity at 0.2 C-rate up to 100 cycles.« less

Coating system to permit direct brazing of ceramics

DOEpatents

Cadden, Charles H.; Hosking, F. Michael

2003-01-01

This invention relates to a method for preparing the surface of a ceramic component that enables direct brazing using a non-active braze alloy. The present invention also relates to a method for directly brazing a ceramic component to a ceramic or metal member using this method of surface preparation, and to articles produced by using this brazing method. The ceramic can be high purity alumina. The method comprises applying a first coating of a silicon-bearing oxide material (e.g. silicon dioxide or mullite (3Al.sub.2 O.sub.3.2SiO.sub.2) to the ceramic. Next, a thin coating of active metal (e.g. Ti or V) is applied. Finally, a thicker coating of a non-active metal (e.g. Au or Cu) is applied. The coatings can be applied by physical vapor deposition (PVD). Alternatively, the active and non-active metals can be co-deposited (e.g. by sputtering a target made of mullite). After all of the coatings have been applied, the ceramic can be fired at a high temperature in a non-oxidizing environment to promote diffusion, and to enhance bonding of the coatings to the substrate. After firing, the metallized ceramic component can be brazed to other components using a conventional non-active braze alloy. Alternatively, the firing and brazing steps can be combined into a single step. This process can replace the need to perform a "moly-manganese" metallization step.

Switchable Super-Hydrophilic/Hydrophobic Indium Tin Oxide (ITO) Film Surfaces on Reactive Ion Etching (RIE) Textured Si Wafer.

PubMed

Kim, Hwa-Min; Litao, Yao; Kim, Bonghwan

2015-11-01

We have developed a surface texturing process for pyramidal surface features along with an indium tin oxide (ITO) coating process to fabricate super-hydrophilic conductive surfaces. The contact angle of a water droplet was less than 5 degrees, which means that an extremely high wettability is achievable on super-hydrophilic surfaces. We have also fabricated a super-hydrophobic conductive surface using an additional coating of polytetrafluoroethylene (PTFE) on the ITO layer coated on the textured Si surface; the ITO and PTFE films were deposited by using a conventional sputtering method. We found that a super-hydrophilic conductive surface is produced by ITO coated on the pyramidal Si surface (ITO/Si), with contact angles of approximately 0 degrees and a resistivity of 3 x 10(-4) Ω x cm. These values are highly dependent on the substrate temperature during the sputtering process. We also found that the super-hydrophobic conductive surface produced by the additional coating of PTFE on the pyramidal Si surface with an ITO layer (PTFE/ITO/Si) has a contact angle of almost 160 degrees and a resistivity of 3 x 10(-4) Ω x cm, with a reflectance lower than 9%. Therefore, these processes can be used to fabricate multifunctional features of ITO films for switchable super-hydrophilic and super-hydrophobic surfaces.

Molten metal containment vessel with rare earth oxysulfide protective coating thereon and method of making same

DOEpatents

Krikorian, Oscar H.; Curtis, Paul G.

1992-01-01

An improved molten metal containment vessel is disclosed in which wetting of the vessel's inner wall surfaces by molten metal is inhibited by coating at least the inner surfaces of the containment vessel with one or more rare earth oxysulfide or rare earth sulfide compounds to inhibit wetting and or adherence by the molten metal to the surfaces of the containment vessel.

Ultrasonic spray coating polymer and small molecular organic film for organic light-emitting devices.

PubMed

Liu, Shihao; Zhang, Xiang; Zhang, Letian; Xie, Wenfa

2016-11-22

Ultrasonic spray coating process (USCP) with high material -utilization, low manufacture costs and compatibility to streamline production has been attractive in researches on photoelectric devices. However, surface tension exists in the solvent is still a huge obstacle to realize smooth organic film for organic light emitting devices (OLEDs) by USCP. Here, high quality polymer anode buffer layer and small molecular emitting layer are successfully realized through USCP by introducing extra-low surface tension diluent and surface tension control method. The introduction of low surface tension methyl alcohol is beneficial to the formation of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) films and brings obvious phase separation and improved conductivity to PEDOT:PSS film. Besides, a surface tension control method, in which new stable tension equilibrium is built at the border of wetting layer, is proposed to eliminate the effect of surface tension during the solvent evaporation stage of ultrasonic spray coating the film consists of 9,9-Spirobifluoren-2-yl-diphenyl-phosphine oxide doped with 10 wt% tris [2-(p -tolyl) pyridine] iridium (III). A smooth and homogenous small molecular emitting layer without wrinkles is successfully realized. The effectiveness of the ultrasonic spray coating polymer anode buffer layer and small molecular emitting layer are also proved by introducing them in OLEDs.

Ultrasonic spray coating polymer and small molecular organic film for organic light-emitting devices

NASA Astrophysics Data System (ADS)

Liu, Shihao; Zhang, Xiang; Zhang, Letian; Xie, Wenfa

2016-11-01

Ultrasonic spray coating process (USCP) with high material -utilization, low manufacture costs and compatibility to streamline production has been attractive in researches on photoelectric devices. However, surface tension exists in the solvent is still a huge obstacle to realize smooth organic film for organic light emitting devices (OLEDs) by USCP. Here, high quality polymer anode buffer layer and small molecular emitting layer are successfully realized through USCP by introducing extra-low surface tension diluent and surface tension control method. The introduction of low surface tension methyl alcohol is beneficial to the formation of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) films and brings obvious phase separation and improved conductivity to PEDOT:PSS film. Besides, a surface tension control method, in which new stable tension equilibrium is built at the border of wetting layer, is proposed to eliminate the effect of surface tension during the solvent evaporation stage of ultrasonic spray coating the film consists of 9,9-Spirobifluoren-2-yl-diphenyl-phosphine oxide doped with 10 wt% tris [2-(p -tolyl) pyridine] iridium (III). A smooth and homogenous small molecular emitting layer without wrinkles is successfully realized. The effectiveness of the ultrasonic spray coating polymer anode buffer layer and small molecular emitting layer are also proved by introducing them in OLEDs.

Oxygen Plasma Effect on QCM Sensor Coated Polystyrene Film

NASA Astrophysics Data System (ADS)

Khusnah, N. F.; Sakti, S. P.; Santjojo, D. J. D. H.

2018-05-01

Hydrophobicity property of polystyrene (PS) thin film is one of the essential factors to be considered in the development of quartz crystal microbalance (QCM) biosensor using polystyrene as matrix layer. Many methods were developed to improve the immobilization rate of the biomolecule on the sensor surface without affecting the QCM essential works. Surface modification of the sensor surface aims to modify the physical and or chemical property of the surface. A straightforward method, the fast, environmentally-friendly, and low-cost solution to modify the sensor surface coated with polystyrene film is using oxygen plasma. In this experiment, the polystyrene film was spin-coated on both surface of QCM electrodes and then heated at 100 °C. The specimen is then placed for 5 min long in a chamber filled with oxygen plasma generated by 2 MHz RF-DC high-density plasma system. The relationship between DC-bias used and the changes in morphology properties of the coated film was characterized by Topography Measurement System (TMS) and Contact Angle Measurement. The electrical characteristic of QCM was also characterized using Impedance Analyzer. It was revealed that the contact angle of oxygen plasma treated film is changed and depicted the hydrophobic character. Also, there is an increasing resonance frequency of the sensor after oxygen plasma treatment indicates an etching mechanism occurs during plasma treatment.

Ultrasonic spray coating polymer and small molecular organic film for organic light-emitting devices

PubMed Central

Liu, Shihao; Zhang, Xiang; Zhang, Letian; Xie, Wenfa

2016-01-01

Ultrasonic spray coating process (USCP) with high material -utilization, low manufacture costs and compatibility to streamline production has been attractive in researches on photoelectric devices. However, surface tension exists in the solvent is still a huge obstacle to realize smooth organic film for organic light emitting devices (OLEDs) by USCP. Here, high quality polymer anode buffer layer and small molecular emitting layer are successfully realized through USCP by introducing extra-low surface tension diluent and surface tension control method. The introduction of low surface tension methyl alcohol is beneficial to the formation of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) films and brings obvious phase separation and improved conductivity to PEDOT:PSS film. Besides, a surface tension control method, in which new stable tension equilibrium is built at the border of wetting layer, is proposed to eliminate the effect of surface tension during the solvent evaporation stage of ultrasonic spray coating the film consists of 9,9-Spirobifluoren-2-yl-diphenyl-phosphine oxide doped with 10 wt% tris [2-(p -tolyl) pyridine] iridium (III). A smooth and homogenous small molecular emitting layer without wrinkles is successfully realized. The effectiveness of the ultrasonic spray coating polymer anode buffer layer and small molecular emitting layer are also proved by introducing them in OLEDs. PMID:27874030

Fortifying the Bone-Implant Interface Part 1: An In Vitro Evaluation of 3D-Printed and TPS Porous Surfaces.

PubMed

MacBarb, Regina F; Lindsey, Derek P; Bahney, Chelsea S; Woods, Shane A; Wolfe, Mark L; Yerby, Scott A

2017-01-01

An aging society and concomitant rise in the incidence of impaired bone health have led to the need for advanced osteoconductive spinal implant surfaces that promote greater biological fixation ( e.g. for interbody fusion cages, sacroiliac joint fusion implants, and artificial disc replacements). Additive manufacturing, i.e. 3D-printing, may improve bone integration by generating biomimetic spinal implant surfaces that mimic bone morphology. Such surfaces may foster an enhanced cellular response compared to traditional implant surfacing processes. This study investigated the response of human osteoblasts to additive manufactured (AM) trabecular-like titanium implant surfaces compared to traditionally machined base material with titanium plasma spray (TPS) coated surfaces, with and without a nanocrystalline hydroxyapatite (HA) coating. For TPS-coated discs, wrought Ti6Al4V ELI was machined and TPS-coating was applied. For AM discs, Ti6Al4V ELI powder was 3D-printed to form a solid base and trabecular-like porous surface. The HA-coating was applied via a precipitation dip-spin method. Surface porosity, pore size, thickness, and hydrophilicity were characterized. Initial cell attachment, proliferation, alkaline phosphatase (ALP) activity, and calcium production of hFOB cells ( n =5 per group) were measured. Cells on AM discs exhibited expedited proliferative activity. While there were no differences in mean ALP expression and calcium production between TPS and AM discs, calcium production on the AM discs trended 48% higher than on TPS discs ( p =0.07). Overall, HA-coating did not further enhance results compared to uncoated TPS and AM discs. Results demonstrate that additive manufacturing allows for controlled trabecular-like surfaces that promote earlier cell proliferation and trends toward higher calcium production than TPS coating. Results further showed that nanocrystalline HA may not provide an advantage on porous titanium surfaces. Additive manufactured porous titanium surfaces may induce a more osteogenic environment compared to traditional TPS, and thus present as an attractive alternative to TPS-coating for orthopedic spinal implants.

Micromorphological characterization of zinc/silver particle composite coatings.

PubMed

Méndez, Alia; Reyes, Yolanda; Trejo, Gabriel; StĘpień, Krzysztof; Ţălu, Ştefan

2015-12-01

The aim of this study was to evaluate the three-dimensional (3D) surface micromorphology of zinc/silver particles (Zn/AgPs) composite coatings with antibacterial activity prepared using an electrodeposition technique. These 3D nanostructures were investigated over square areas of 5 μm × 5 μm by atomic force microscopy (AFM), fractal, and wavelet analysis. The fractal analysis of 3D surface roughness revealed that (Zn/AgPs) composite coatings have fractal geometry. Triangulation method, based on the linear interpolation type, applied for AFM data was employed in order to characterise the surfaces topographically (in amplitude, spatial distribution and pattern of surface characteristics). The surface fractal dimension Df , as well as height values distribution have been determined for the 3D nanostructure surfaces. © 2015 The Authors published by Wiley Periodicals, Inc.

Report: Discussion on the development of nano Ag/TiO2 coating bracket and its antibacterial property and biocompatibility in orthodontic treatment.

PubMed

Zhang, Ronghe; Zhang, Weiwei; Bai, Xueyan; Song, Xiaotong; Wang, Chunyan; Gao, Xinxin; Tian, Xubiao; Liu, Fengzhen

2015-03-01

This paper aims to explore the antibacterial property of nano Ag/TiO2 coating bracket for the common bacteria in oral cavity, and discuss its biocompatibility. Micro morphology in the surface of nano Ag/TiO2 coating bracket was detected by scanning electron microscope (SEM), and surface roughness of ordinary mental bracket, nano TiO2 coating bracket and nano Ag/TiO2 coating bracket were measured. First, antibacterial property of nano Ag/TiO2 coating bracket on the common bacteria in oral cavity was studied by sticking membrane method. Secondly, bonding strength of nano TiO2 coating and nano Ag/TiO2 coating bracket in groups were detected by scratching test. The result showed that, the synthetic nano Ag/TiO2 coating was nanogranular films with rigorous organizational structure, presenting as smooth and clean surface, and antibacterial rate of nano Ag/TiO2 coating for the common bacteria in oral cavity for 20 min was more than 79% in the dark. All the findings suggested that, nano Ag/TiO2 coating bracket not only has antibacterial effect but also has good biocompatibility, therefore, it can satisfy the clinical request of orthodontic treatment.

Medicine Delivery Device with Integrated Sterilization and Detection

NASA Technical Reports Server (NTRS)

Sheam, Michael J.; Greer, Harold F.; Manohara, Harish

2013-01-01

Sterile delivery devices can be created by integrating a medicine delivery instrument with surfaces that are coated with germicidal and anti-fouling material. This requires that a large-surface-area template be developed within a constrained volume to ensure good contact between the delivered medicine and the germicidal material. Both of these can be integrated using JPL-developed silicon nanotip or cryo-etch black silicon technologies with atomic layer deposition (ALD) coating of specific germicidal layers. Nanofabrication techniques that are used to produce a microfluidics device are also capable of synthesizing extremely hig-hsurface-area templates in precise locations, and coating those surfaces with conformal films to manipulate their surface properties. This methodology has been successfully applied at JPL to produce patterned and coated silicon nanotips (also known as black silicon) to manipulate the hydrophilicity of surfaces to direct the spreading of fluids in microdevices. JPL s ALD technique is an ideal method to produce the highly conformal coatings required for this type of application. Certain materials, such as TiO2, have germicidal and anti-fouling properties when they are illuminated with UV light. The proposed delivery device contacts medicine with this high-surface-area black silicon surface coated with a thin-film germicidal deposited conformally with ALD. The coating can also be illuminated with ultraviolet light for the purpose of sterilization or identification of the medicine itself. This constrained volume that is located immediately prior to delivery into a patient, ensures that the medicine delivery device is inherently sterile.

The Design of Simple Bacterial Microarrays: Development towards Immobilizing Single Living Bacteria on Predefined Micro-Sized Spots on Patterned Surfaces.

PubMed

Arnfinnsdottir, Nina Bjørk; Ottesen, Vegar; Lale, Rahmi; Sletmoen, Marit

2015-01-01

In this paper we demonstrate a procedure for preparing bacterial arrays that is fast, easy, and applicable in a standard molecular biology laboratory. Microcontact printing is used to deposit chemicals promoting bacterial adherence in predefined positions on glass surfaces coated with polymers known for their resistance to bacterial adhesion. Highly ordered arrays of immobilized bacteria were obtained using microcontact printed islands of polydopamine (PD) on glass surfaces coated with the antiadhesive polymer polyethylene glycol (PEG). On such PEG-coated glass surfaces, bacteria were attached to 97 to 100% of the PD islands, 21 to 62% of which were occupied by a single bacterium. A viability test revealed that 99% of the bacteria were alive following immobilization onto patterned surfaces. Time series imaging of bacteria on such arrays revealed that the attached bacteria both divided and expressed green fluorescent protein, both of which indicates that this method of patterning of bacteria is a suitable method for single-cell analysis.

Flow accelerated organic coating degradation

NASA Astrophysics Data System (ADS)

Zhou, Qixin

Applying organic coatings is a common and the most cost effective way to protect metallic objects and structures from corrosion. Water entry into coating-metal interface is usually the main cause for the deterioration of organic coatings, which leads to coating delamination and underfilm corrosion. Recently, flowing fluids over sample surface have received attention due to their capability to accelerate material degradation. A plethora of works has focused on the flow induced metal corrosion, while few studies have investigated the flow accelerated organic coating degradation. Flowing fluids above coating surface affect corrosion by enhancing the water transport and abrading the surface due to fluid shear. Hence, it is of great importance to understand the influence of flowing fluids on the degradation of corrosion protective organic coatings. In this study, a pigmented marine coating and several clear coatings were exposed to the laminar flow and stationary immersion. The laminar flow was pressure driven and confined in a flow channel. A 3.5 wt% sodium chloride solution and pure water was employed as the working fluid with a variety of flow rates. The corrosion protective properties of organic coatings were monitored inline by Electrochemical Impedance Spectroscopy (EIS) measurement. Equivalent circuit models were employed to interpret the EIS spectra. The time evolution of coating resistance and capacitance obtained from the model was studied to demonstrate the coating degradation. Thickness, gloss, and other topography characterizations were conducted to facilitate the assessment of the corrosion. The working fluids were characterized by Fourier Transform Infrared Spectrometer (FTIR) and conductivity measurement. The influence of flow rate, fluid shear, fluid composition, and other effects in the coating degradation were investigated. We conclude that flowing fluid on the coating surface accelerates the transport of water, oxygen, and ions into the coating, as well as promotes the migration of coating materials from the coating into the working fluid, where coatings experience more severe deterioration in their barrier property under flowing conditions. Pure water has shown to be a much more aggressive working fluid than electrolyte solutions. The flowing fluid over the coating surface could be used as an effective acceleration method.

The effect of nano-structured alumina coating on resin-bond strength to zirconia ceramics.

PubMed

Jevnikar, Peter; Krnel, Kristoffer; Kocjan, Andraz; Funduk, Nenad; Kosmac, Tomaz

2010-07-01

The aim of this study was to functionalize the surface of yttria partially stabilized tetragonal zirconia ceramics (Y-TZP) with a nano-structured alumina coating to improve resin bonding. A total of 120 densely sintered disc-shaped specimens (15.5+/-0.03 mm in diameter and 2.6+/-0.03 mm thick) were produced from biomedical-grade TZ-3YB-E zirconia powder (Tosoh, Tokyo, Japan), randomly divided into three groups of 40 and subjected to the following surface treatments: AS - as-sintered; APA - airborne-particle abraded; POL - polished. Half of the discs in each group received an alumina coating that was fabricated by exploiting the hydrolysis of aluminium nitride (AlN) powder (groups AS-C, APA-C, POL-C). The coating was characterized using scanning electron microscopy (SEM), atomic force microscopy (AFM), and transmission electron microscopy (TEM). The shear-bond strength of the self-etching composite resin (RelyX Unicem, 3M ESPE, USA) was then studied for the coated and uncoated surfaces of the as-sintered, polished and airborne-particle abraded specimens before and after thermocycling (TC). The SEM/TEM analyses revealed that the application of an alumina coating to Y-TZP ceramics created a highly retentive surface for resin penetration. The coating showed good surface coverage and a uniform thickness of 240 nm. The resin-bond strength to the groups AS-C, APA-C, POL-C was significantly higher than to the groups AS, APA and POL, both before and after TC (p< or =0.05). During TC all the specimens in the POL and AS groups debonded spontaneously. In contrast, the TC did not affect the bond strength of the AS-C, POL-C and APA-C groups. A non-invasive method has been developed that significantly improves resin-bond strength to Y-TZP ceramics. After surface functionalization the bond survives thermocycling without reduction in strength. The method is relatively simple and has the potential to become an effective conditioning method for zirconia ceramics. Copyright 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Surface modified aerogel monoliths

NASA Technical Reports Server (NTRS)

Leventis, Nicholas (Inventor); Johnston, James C. (Inventor); Kuczmarski, Maria A. (Inventor); Meador, Mary Ann B. (Inventor)

2013-01-01

This invention comprises reinforced aerogel monoliths such as silica aerogels having a polymer coating on its outer geometric surface boundary, and to the method of preparing said aerogel monoliths. The polymer coatings on the aerogel monoliths are derived from polymer precursors selected from the group consisting of isocyanates as a precursor, precursors of epoxies, and precursors of polyimides. The coated aerogel monoliths can be modified further by encapsulating the aerogel with the polymer precursor reinforced with fibers such as carbon or glass fibers to obtain mechanically reinforced composite encapsulated aerogel monoliths.

Surface pressure field mapping using luminescent coatings

NASA Technical Reports Server (NTRS)

Mclachlan, B. G.; Kavandi, J. L.; Callis, J. B.; Gouterman, M.; Green, E.; Khalil, G.; Burns, D.

1993-01-01

In recent experiments we demonstrated the feasibility of using the oxygen dependence of luminescent molecules for surface pressure measurement in aerodynamic testing. This technique is based on the observation that for many luminescent molecules the light emitted increases as the oxygen partial pressure, and thus the air pressure, the molecules see decreases. In practice the surface to be observed is coated with an oxygen permeable polymer containing a luminescent molecule and illuminated with ultraviolet radiation. The airflow induced surface pressure field is seen as a luminescence intensity distribution which can be measured using quantitative video techniques. Computer processing converts the video data into a map of the surface pressure field. The experiments consisted of evaluating a trial luminescent coating in measuring the static surface pressure field over a two-dimensional NACA-0012 section model airfoil for Mach numbers ranging from 0.3 and 0.66. Comparison of the luminescent coating derived pressures were made to those obtained from conventional pressure taps. The method along with the experiment and its results will be described.

Target-specific cellular uptake of PLGA nanoparticles coated with poly(L-lysine)-poly(ethylene glycol)-folate conjugate.

PubMed

Kim, Sun Hwa; Jeong, Ji Hoon; Chun, Ki Woo; Park, Tae Gwan

2005-09-13

Poly(D,L-lactic-co-glycolic acid) (PLGA) nanoparticles with anionic surface charge were surface coated with cationic di-block copolymer, poly(L-lysine)-poly(ethylene glycol)-folate (PLL-PEG-FOL) conjugate, for enhancing their site-specific intracellular delivery against folate receptor overexpressing cancer cells. The PLGA nanoparticles coated with the conjugate were characterized in terms of size, surface charge, and change in surface composition by XPS. By employing the flow cytometry method and confocal image analysis, the extent of cellular uptake was comparatively evaluated under various conditions. PLL-PEG-FOL coated PLGA nanoparticles demonstrated far greater extent of cellular uptake to KB cells, suggesting that they were mainly taken up by folate receptor-mediated endocytosis. The enhanced cellular uptake was also observed even in the presence of serum proteins, possibly due to the densely seeded PEG chains. The PLL-PEG-FOL coated PLGA nanoparticles could be potentially applied for cancer cell targeted delivery of various therapeutic agents.

Preservation of York Minster historic limestone by hydrophobic surface coatings

PubMed Central

Walker, Rachel A.; Wilson, Karen; Lee, Adam F.; Woodford, Julia; Grassian, Vicki H.; Baltrusaitis, Jonas; Rubasinghege, Gayan; Cibin, Giannantonio; Dent, Andrew

2012-01-01

Magnesian limestone is a key construction component of many historic buildings that is under constant attack from environmental pollutants notably by oxides of sulfur via acid rain, particulate matter sulfate and gaseous SO2 emissions. Hydrophobic surface coatings offer a potential route to protect existing stonework in cultural heritage sites, however, many available coatings act by blocking the stone microstructure, preventing it from ‘breathing' and promoting mould growth and salt efflorescence. Here we report on a conformal surface modification method using self-assembled monolayers of naturally sourced free fatty acids combined with sub-monolayer fluorinated alkyl silanes to generate hydrophobic (HP) and super hydrophobic (SHP) coatings on calcite. We demonstrate the efficacy of these HP and SHP surface coatings for increasing limestone resistance to sulfation, and thus retarding gypsum formation under SO2/H2O and model acid rain environments. SHP treatment of 19th century stone from York Minster suppresses sulfuric acid permeation. PMID:23198088

Surface modification of air plasma spraying WC-12%Co cermet coating by laser melting technique

NASA Astrophysics Data System (ADS)

Afzal, M.; Ajmal, M.; Nusair Khan, A.; Hussain, A.; Akhter, R.

2014-03-01

Tungsten carbide cermet powder with 12%Co was deposited on stainless steel substrate by air plasma spraying method. Two types of coatings were produced i.e. thick (430 µm) and thin (260 µm) with varying porosity and splat morphology. The coated samples were treated with CO2 laser under the shroud of inert atmosphere. A series of experimentation was done in this regard, to optimize the laser parameters. The plasma sprayed coated surfaces were then laser treated on the same parameters. After laser melting the treated surfaces were characterized and compared with as-sprayed surfaces. It was observed that the thickness of the sprayed coatings affected the melt depth and the achieved microstructures. It was noted that phases like Co3W3C, Co3W9C4 and W were formed during the laser melting in both samples. The increase in hardness was attributed to the formation of these phases.

[Indoor simulation on dew formation on plant leaves].

PubMed

Gao, Zhi-Yong; Wang, You-Ke; Wei, Xin-Guang; Liu, Shou-Yang; He, Zi-Li; Zhou, Yu-Hong

2014-03-01

Dew forming on plant leaves through water condensation plays a significant ecological role in arid and semi-arid areas as an ignorable fraction of water resources. In this study, an artificial intelligent climate chamber and an automatic temperature-control system for leaves were implemented to regulate the ambient temperature, the leaf surface temperature and the leaf inclination for dew formation. The impact of leaf inclination, ambient temperature and dew point-leaf temperature depression on the rate and quantity of dew accumulation on leaf surface were analyzed. The results indicated that the accumulation rate and the maximum volume of dew on leaves decreased with increasing the leaf inclination while increased with the increment of dew point-leaf temperature depression, ambient temperature and relative humidity. Under the horizontal configuration, dew accumulated linearly on leaf surface over time until the maximum volume (0.80 mm) was reached. However, dew would fall down after reaching the maximum volume when the leaf inclination existed (45 degrees or 90 degrees), significantly slowing down the accumulative rate, and the zigzag pattern for the dynamic of dew accumulation appeared.

40 CFR 60.441 - Definitions and symbols.

Code of Federal Regulations, 2010 CFR

2010-07-01

... web. Coating line means any number or combination of adhesive, release, or precoat coating applicators... solids content of the coated adhesive, release, or precoat as measured by Method 24. Flashoff area means... than an adhesive or release is applied to a surface during the production of a pressure sensitive tape...

Figure 12(a) Effects of Inclining Water. Figure 12(b) Sand. NASA document NASA-TN-D-56 An investigation to determine conditions under which downwash from VTOL aircraft will start surface erosion from various types of terrain

NASA Image and Video Library

1959-05-04

Figure 12(a) Effects of Inclining Water. Figure 12(b) Sand. NASA-TN-D-56 An investigation to determine conditions under which downwash from VTOL aircraft will start surface erosion from various types of terrain.

In-situ phosphatizing coatings for aerospace, OEM and coil coating applications

NASA Astrophysics Data System (ADS)

Neuder, Heather Aurelia

The current metal coating process is a multi-step process. The surface is cleaned, primered, dried and then painted. The process is labor intensive and time consuming. The wash primer is a conversion coating, which prepares metal surface for better paint adhesion. The wash primers currently used often contain hexavalent chromium (Cr6+), which seals the pores in the conversion coating. The presence of hexavalent chromium, a known carcinogen, and volatile organic compounds (VOCs) make waste disposal expensive and pose dangers to workers. The novel technique of in-situ phosphatizing coating (ISPC) is a single-step, chrome-free alternative to the present coating practice. Formulation of an ISPC involves predispersal of an in-situ phosphatizing reagent (ISPR) into the paint system to form a stable formulation. The ISPR reacts with the metal surface and bonds with the paint film simultaneously, which eliminates the need for a conversion coating. In acid catalyzed paint systems, such as polyester-melamine paints, the ISPR also catalyzes cross-linking reactions between the melamine and the polyester polyols. ISPCs are formulated using commercially available coating systems including: polyester-melamine, two-component epoxy, polyurethane and high-hydroxy content polyester-melamine coil coating. The ISPCs are applied to metal substrates and their performances are evaluated using electrochemical, thermal and standard American Society for Testing and Materials (ASTM) testing methods. In addition, ISPCs were designed and formulated based on: (1) phosphate chemistry, (2) polymer chemistry, (3) sol-gel chemistry, and (4) the ion-exchange principle. Organo-functionalized silanes, which serve as excellent coupling and dispersion agents, are incorporated into the optimized ISPC formula and evaluated using standard ASTM testing methods and electrochemical spectroscopy. Also, an ion-exchange pigment, which leads to better adhesion by forming a mixed metal silicate surface, is dispersed into an ISPC and the performance of the final coating formulation is evaluated. Successful ISPCs formulated for multiple coating systems exhibited excellent adhesion, hardness and gloss, which supports their suitability as a chrome-free, single-step alternative for aerospace, original equipment manufacturing (OEM) and coil coating applications.

Influence of epoxy, polytetrafluoroethylene (PTFE) and rhodium surface coatings on surface roughness, nano-mechanical properties and biofilm adhesion of nickel titanium (Ni-Ti) archwires

NASA Astrophysics Data System (ADS)

Asiry, Moshabab A.; AlShahrani, Ibrahim; Almoammar, Salem; Durgesh, Bangalore H.; Kheraif, Abdulaziz A. Al; Hashem, Mohamed I.

2018-02-01

Aim. To investigate the effect of epoxy, polytetrafluoroethylene (PTFE) and rhodium surface coatings on surface roughness, nano-mechanical properties and biofilm adhesion of nickel titanium (Ni-Ti) archwires Methods. Three different coated (Epoxy, polytetrafluoroethylene (PTFE) and rhodium) and one uncoated Ni-Ti archwires were evaluated in the present study. Surface roughness (Ra) was assessed using a non-contact surface profilometer. The mechanical properties (nano-hardness and elastic modulus) were measured using a nanoindenter. Bacterial adhesion assays were performed using Streptococcus mutans (MS) and streptococcus sobrinus (SS) in an in-vitro set up. The data obtained were analyzed using analyses of variance, Tukey’s post hoc test and Pearson’s correlation coefficient test. Result. The highest Ra values (1.29 ± 0.49) were obtained for epoxy coated wires and lowest Ra values (0.29 ± 0.16) were obtained for the uncoated wires. No significant differences in the Ra values were observed between the rhodium coated and uncoated archwires (P > 0.05). The highest nano-hardness (3.72 ± 0.24) and elastic modulus values (61.15 ± 2.59) were obtained for uncoated archwires and the lowest nano-hardness (0.18 ± 0.10) and elastic modulus values (4.84 ± 0.65) were observed for epoxy coated archwires. No significant differences in nano-hardness and elastic modulus values were observed between the coated archwires (P > 0.05). The adhesion of Streptococcus mutans (MS) to the wires was significantly greater than that of streptococcus sobrinus (SS). The epoxy coated wires demonstrated an increased adhesion of MS and SS and the uncoated wires demonstrated decreased biofilm adhesion. The Spearman correlation test showed that MS and SS adhesion was positively correlated with the surface roughness of the wires. Conclusion. The different surface coatings significantly influence the roughness, nano-mechanical properties and biofilm adhesion parameters of the archwires. The evaluated parameters were most influenced by epoxy coating followed by PTFE and rhodium coating. A positive correlation was detected between surface roughness and biofilm adhesion.

Asymmetric bursting of Taylor bubble in inclined tubes

NASA Astrophysics Data System (ADS)

Rana, Basanta Kumar; Das, Arup Kumar; Das, Prasanta Kumar

2016-08-01

In the present study, experiments have been reported to explain the phenomenon of approach and collapse of an asymmetric Taylor bubble at free surface inside an inclined tube. Four different tube inclinations with horizontal (30°, 45°, 60° and 75°) and two different fluids (water and silicon oil) are considered for the experiment. Using high speed imaging, we have investigated the approach, puncture, and subsequent liquid drainage for re-establishment of the free surface. The present study covers all the aspects in the collapse of an asymmetric Taylor bubble through the generation of two films, i.e., a cap film which lies on top of the bubble and an asymmetric annular film along the tube wall. Retraction of the cap film is studied in detail and its velocity has been predicted successfully for different inclinations and fluids. Film drainage formulation considering azimuthal variation is proposed which also describes the experimental observations well. In addition, extrapolation of drainage velocity pattern beyond the experimental observation limit provides insight into the total collapse time of bubbles at different inclinations and fluids.

The improvement of moisture resistance and thermal stability of Ca 3SiO 4Cl 2:Eu 2+ phosphor coated with SiO 2

NASA Astrophysics Data System (ADS)

Zhuang, Jiaqing; Xia, Zhiguo; Liu, Haikun; Zhang, Zepeng; Liao, Libing

2011-02-01

Green-emitting phosphors Ca3SiO4Cl2:Eu2+ were prepared by the high temperature solid-state method. Sol-gel process was adopted to encapsulate the as-prepared phosphors with tetraethylorthosilicate (TEOS) as silicon coating reagent. Fluorescence spectrometer, scanning electron microscopy (SEM) and powder X-ray diffraction (XRD) patterns were employed to characterize the emission spectra, the surface morphologies and the phase structures, respectively. The chemical stability testing was operated by the method of soaking the phosphors in deionized water and roasting them at different temperatures. The results indicated that the surfaces of the green phosphors were evenly coated by SiO2 and the phase structure of the coated phosphors remained the same as the uncoated samples. The luminance centre of Eu2+ did not shift after surface treatment and the luminance intensity of coated phosphors was lower than that of the uncoated samples. The results demonstrated that the water-resistance stability of the coated phosphor was improved to some degree because the pH value and the luminance intensity variation were both smaller than the uncoated phosphor after steeping within the same time. Moreover, the thermal stability of coated phosphors was enhanced obviously compared to the original samples based on the temperature dependent emission spectra measurement.

Anatomy of the proximal tibiofibular joint and interosseous membrane, and their contributions to joint kinematics in below-knee amputations.

PubMed

Burkhart, Timothy A; Asa, Benjamin; Payne, Michael W C; Johnson, Marjorie; Dunning, Cynthia E; Wilson, Timothy D

2015-02-01

A result of below-knee amputations (BKAs) is abnormal motion that occurs about the proximal tibiofibular joint (PTFJ). While it is known that joint morphology may play a role in joint kinematics, this is not well understood with respect to the PTFJ. Therefore, the purposes of this study were: (i) to characterize the anatomy of the PTFJ and statistically analyze the relationships within the joint; and (ii) to determine the relationships between the PTFJ characteristics and the degree of movement of the fibula in BKAs. The PTFJ was characterized in 40 embalmed specimens disarticulated at the knee, and amputated through the mid-tibia and fibula. Four metrics were measured: inclination angle (angle at which the fibula articulates with the tibia); tibial and fibular articular surface areas; articular surface concavity and shape. The specimens were mechanically tested by applying a load through the biceps femoris tendon, and the degree of motion about the tibiofibular joint was measured. Regression analyses were performed to determine the relationships between the different PTFJ characteristics and the magnitude of fibular abduction. Finally, Pearson correlation analyses were performed on inclination angle and surface area vs. fibular kinematics. The inclination angle measured on the fibula was significantly greater than that measured on the tibia. This difference may be attributed to differences in concavity of the tibial and fibular surfaces. Surface area measured on the tibia and fibula was not statistically different. The inclination angle was not statistically correlated to surface area. However, when correlating fibular kinematics in BKAs, inclination angle was positively correlated to the degree of fibular abduction, whereas surface area was negatively correlated. The characteristics of the PTFJ dictate the amount of fibular movement, specifically, fibular abduction in BKAs. Predicting BKA complications based on PTFJ characteristics can lead to recommendations in treatment. © 2014 Anatomical Society.

The Otto Aufranc Award: Enhanced Biocompatibility of Stainless Steel Implants by Titanium Coating and Microarc Oxidation

PubMed Central

Lim, Young Wook; Kwon, Soon Yong; Sun, Doo Hoon

2010-01-01

Background Stainless steel is one of the most widely used biomaterials for internal fixation devices, but is not used in cementless arthroplasty implants because a stable oxide layer essential for biocompatibility cannot be formed on the surface. We applied a Ti electron beam coating, to form oxide layer on the stainless steel surface. To form a thicker oxide layer, we used a microarc oxidation process on the surface of Ti coated stainless steel. Modification of the surface using Ti electron beam coating and microarc oxidation could improve the ability of stainless steel implants to osseointegrate. Questions/purposes The ability of cells to adhere to grit-blasted, titanium-coated, microarc-oxidated stainless steel in vitro was compared with that of two different types of surface modifications, machined and titanium-coated, and microarc-oxidated. Methods We performed energy-dispersive x-ray spectroscopy and scanning electron microscopy investigations to assess the chemical composition and structure of the stainless steel surfaces and cell morphology. The biologic responses of an osteoblastlike cell line (SaOS-2) were examined by measuring proliferation (cell proliferation assay), differentiation (alkaline phosphatase activity), and attraction ability (cell migration assay). Results Cell proliferation, alkaline phosphatase activity, migration, and adhesion were increased in the grit-blasted, titanium-coated, microarc-oxidated group compared to the two other groups. Osteoblastlike cells on the grit-blasted, titanium-coated, microarc-oxidated surface were strongly adhered, and proliferated well compared to those on the other surfaces. Conclusions The surface modifications we used (grit blasting, titanium coating, microarc oxidation) enhanced the biocompatibility (proliferation and migration of osteoblastlike cells) of stainless steel. Clinical Relevance This process is not unique to stainless steel; it can be applied to many metals to improve their biocompatibility, thus allowing a broad range of materials to be used for cementless implants. PMID:20936386

Influence of citric acid on the surface texture of glass ionomer restorative materials

PubMed Central

Reddy, Dappili Swami Ranga; Kumar, Ramachandran Anil; Venkatesan, Sokkalingam Mothilal; Narayan, Gopal Shankar; Duraivel, Dasarathan; Indra, Rajamani

2014-01-01

Aim: This study determined the effectiveness of G-coat plus surface protective agent over petroleum jelly on the surface texture of conventional Glass ionomer restorative materials. Materials and Methods: Three chemically cured conventional glass ionomer restorative materials type II, type IX and ketac molar were evaluated in this study. Sixty specimens were made for each restorative material. They were divided into two groups of thirty specimens each. Of the sixty specimens, thirty were coated with G-coat plus (a nano-filler coating) and the rest with petroleum jelly. Thirty samples of both protective coating agents were randomly divided into six groups of five specimens and conditioned in citric acid solutions of differing pH (pH 2, 3, 4, 5, 6 & 7). Each specimen was kept in citric acid for three hours a day, and the rest of time stored in salivary substitute. This procedure was repeated for 8 days. After conditioning, the surface roughness (Ra, μm) of each specimen was measured using a surface profilometer (Taylor & Habson, UK). Data was analyzed using one-way analysis of variance (ANOVA) and Tukey's HSD test at a significance level of 0.05. Results: The surface textures of all the tested glass ionomer restorative materials protected with G-coat plus were not significantly affected by acids at low pH. The surface textures of all the tested glass ionomer restorative materials protected with petroleum jelly coating were significantly affected by acids at low pH. Conclusion: The effects of pH on the surface texture of glass ionomer restoratives are material dependent. Among all the materials tested the surface texture of Type II GIC (Group I) revealed marked deterioration when conditioned in solutions of low pH and was statistically significant. Hence, a protective coating either with G-coat plus or with light polymerized low viscosity unfilled resin adhesives is mandatory for all the glass ionomer restorations to increase the wear resistance of the restorative materials. PMID:25298643

Combinatorial materials research applied to the development of new surface coatings VII: An automated system for adhesion testing

NASA Astrophysics Data System (ADS)

Chisholm, Bret J.; Webster, Dean C.; Bennett, James C.; Berry, Missy; Christianson, David; Kim, Jongsoo; Mayo, Bret; Gubbins, Nathan

2007-07-01

An automated, high-throughput adhesion workflow that enables pseudobarnacle adhesion and coating/substrate adhesion to be measured on coating patches arranged in an array format on 4×8in.2 panels was developed. The adhesion workflow consists of the following process steps: (1) application of an adhesive to the coating array; (2) insertion of panels into a clamping device; (3) insertion of aluminum studs into the clamping device and onto coating surfaces, aligned with the adhesive; (4) curing of the adhesive; and (5) automated removal of the aluminum studs. Validation experiments comparing data generated using the automated, high-throughput workflow to data obtained using conventional, manual methods showed that the automated system allows for accurate ranking of relative coating adhesion performance.

Method of melting metals to reduce contamination from crucibles

DOEpatents

Banker, John G.; Wigginton, Hubert L.

1977-01-01

Contamination of metals from crucible materials during melting operations is reduced by coating the interior surface of the crucible with a ceramic non-reactive with the metallic charge and disposing a metal liner formed from a portion of the metallic charge within the coated crucible. The liner protects the ceramic coating during loading of the remainder of the charge and expands against the ceramic coating during heat-up to aid in sintering the coating.

Dynamic Response and Failure Mechanism of Brittle Rocks Under Combined Compression-Shear Loading Experiments

NASA Astrophysics Data System (ADS)

Xu, Yuan; Dai, Feng

2018-03-01

A novel method is developed for characterizing the mechanical response and failure mechanism of brittle rocks under dynamic compression-shear loading: an inclined cylinder specimen using a modified split Hopkinson pressure bar (SHPB) system. With the specimen axis inclining to the loading direction of SHPB, a shear component can be introduced into the specimen. Both static and dynamic experiments are conducted on sandstone specimens. Given carefully pulse shaping, the dynamic equilibrium of the inclined specimens can be satisfied, and thus the quasi-static data reduction is employed. The normal and shear stress-strain relationships of specimens are subsequently established. The progressive failure process of the specimen illustrated via high-speed photographs manifests a mixed failure mode accommodating both the shear-dominated failure and the localized tensile damage. The elastic and shear moduli exhibit certain loading-path dependence under quasi-static loading but loading-path insensitivity under high loading rates. Loading rate dependence is evidently demonstrated through the failure characteristics involving fragmentation, compression and shear strength and failure surfaces based on Drucker-Prager criterion. Our proposed method is convenient and reliable to study the dynamic response and failure mechanism of rocks under combined compression-shear loading.

Effect of substrate roughness on the apparent surface free energy of sputter deposited superhydrophobic polytetrafluoroethylene coatings: A comparison of experimental data with different theoretical models

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

Selvakumar, N.; Barshilia, Harish C.; Rajam, K. S.

2010-07-15

We have studied the effect of substrate roughness on the wettability and the apparent surface free energy (SFE) of sputter deposited polytetrafluoroethylene (PTFE) coatings deposited on untreated glass (average roughness, R{sub a}=2.0 nm), plasma etched glass (R{sub a}=7.4 nm), and sandblasted glass (R{sub a}=4500 nm) substrates. The wettability of the PTFE coatings deposited on substrates with varying roughnesses was evaluated by measuring the apparent contact angle (CA) using a series of probe liquids from nonpolar aprotic to polar protic. The wettability measurements indicate that an apparent water CA of 152 deg. with a sliding angle of 8 deg. was achievedmore » for PTFE coatings deposited on a substrate with R{sub a}=4500 nm. The superhydrophobicity observed in these coatings is attributed to the presence of dual scale roughness, densely packed microstructure and the presence of CF{sub 3} groups. Unlike the bulk PTFE which is mainly dispersive, the sputter deposited PTFE coatings are expected to have some degree of polar component due to the plasma treatment. In order to calculate the dispersive SFE of PTFE coatings, we have used the Girifalco-Good-Fowkes (GGF) method and validated it with the Zisman model. Furthermore, the Owens-Wendt model has been used to calculate the dispersive and the polar components of the apparent SFE of the PTFE coatings. These results are further corroborated using the Fowkes method. Finally, an ''equation of state'' theory proposed by Neumann has been used to calculate the apparent SFE values of the PTFE coatings. The results indicate that the apparent SFE values of the PTFE coatings obtained from the Owens-Wendt and the Fowkes methods are comparable to those obtained from the Neumann's method. The analyses further demonstrate that the GGF and the Zisman methods underestimate the apparent SFE values of the sputter deposited PTFE coatings.« less

Fabrication of contacts for silicon solar cells including printing burn through layers

DOEpatents

Ginley, David S; Kaydanova, Tatiana; Miedaner, Alexander; Curtis, Calvin J; Van Hest, Marinus Franciscus Antonius Maria

2014-06-24

A method for fabricating a contact (240) for a solar cell (200). The method includes providing a solar cell substrate (210) with a surface that is covered or includes an antireflective coating (220). For example, the substrate (210) may be positioned adjacent or proximate to an outlet of an inkjet printer (712) or other deposition device. The method continues with forming a burn through layer (230) on the coating (220) by depositing a metal oxide precursor (e.g., using an inkjet or other non-contact printing method to print or apply a volume of liquid or solution containing the precursor). The method includes forming a contact layer (240) comprising silver over or on the burn through layer (230), and then annealing is performed to electrically connect the contact layer (240) to the surface of the solar cell substrate (210) through a portion of the burn through layer (230) and the coating (220).

The underlying biological mechanisms of biocompatibility differences between bare and TiN-coated NiTi alloys.

PubMed

Lifeng, Zhao; Yan, Hong; Dayun, Yang; Xiaoying, Lü; Tingfei, Xi; Deyuan, Zhang; Ying, Hong; Jinfeng, Yuan

2011-04-01

TiN coating has been demonstrated to improve the biocompatibility of bare NiTi alloys; however, essential biocompatibility differences between NiTi alloys before and after TiN coating are not known so far. In this study, to explore the underlying biological mechanisms of biocompatibility differences between them, the changes of bare and TiN-coated NiTi alloys in surface chemical composition, morphology, hydrophilicity, Ni ions release, cytotoxicity, apoptosis, and gene expression profiles were compared using energy-dispersive spectroscopy, scanning electron microscopy, contact angle, surface energy, Ni ions release analysis, the methylthiazoltetrazolium (MTT) method, flow cytometry and microarray methods, respectively. Pathways binding to networks and real-time polymerase chain reaction (PCR) were employed to analyze and validate the microarray data, respectively. It was found that, compared with the bare NiTi alloys, TiN coating significantly decreased Ni ions content on the surfaces of the NiTi alloys and reduced the release of Ni ions from the alloys, attenuated the inhibition of Ni ions to the expression of genes associated with anti-inflammatory, and also suppressed the promotion of Ni ions to the expression of apoptosis-related genes. Moreover, TiN coating distinctly improved the hydrophilicity and uniformity of the surfaces of the NiTi alloys, and contributed to the expression of genes participating in cell adhesion and other physiological activities. These results indicate that the TiN-coated NiTi alloys will help overcome the shortcomings of NiTi alloys used in clinical application currently, and can be expected to be a replacement of biomaterials for a medical device field.

CO2 adsorption on modified carbon coated monolith: effect of surface modification by using alkaline solutions

NASA Astrophysics Data System (ADS)

Hosseini, Soraya; Marahel, Ehsan; Bayesti, Iman; Abbasi, Ali; Chuah Abdullah, L.; Choong, Thomas S. Y.

2015-01-01

A monolithic column was used to study the feasibility of modified carbon-coated monolith for recovery of CO2 from gaseous mixtures (He/CO2) in a variety of operating conditions. Carbon-coated monolith was prepared by dip-coating method and modified by two alkaline solutions, i.e. NH3 and KOH. The surface properties of the carbon-coated monolith were altered by functional groups via KOH and NH3 treatments. The comparative study of CO2 uptake by two different adsorbents, i.e. unmodified and modified carbon-coated monolith, demonstrated that the applied modification process had improved CO2 adsorption. The presence of nitrogen- and oxygen-containing functional groups on the surface of the carbon led to an improved level of microporosity on the synthesized carbon-coated monolith. The physical parameters such as higher surface area, lower pore diameter, and larger micropore volume of modified monoliths indicated direct influence on the adsorbed amount of CO2. In the present study, the Deactivation Model is applied to analyze the breakthrough curves. The adsorption capacity increased with an increase in pressure and concentration, while a reduction of CO2 adsorption capacity was occurred with increase in temperature. Ammonia (NH3) and potassium hydroxide (KOH)-modified carbon-coated monolith showed an increase of approximately 12 and 27% in CO2 adsorption, respectively, as compared to unmodified carbon-coated monolith.

Water-repellent coatings prepared by modification of ZnO nanoparticles

NASA Astrophysics Data System (ADS)

Chakradhar, R. P. S.; Dinesh Kumar, V.

Superhydrophobic coatings with a static water contact angle (WCA) > 150° were prepared by modifying ZnO nanoparticles with stearic acid (ZnO@SA). ZnO nanoparticles of size ˜14 nm were prepared by solution combustion method. X-ray diffraction (XRD) studies reveal that as prepared ZnO has hexagonal wurtzite structure whereas the modified coatings convert to zinc stearate. Field emission scanning electron micrographs (FE-SEM) show the dual morphology of the coatings exhibiting both particles and flakes. The flakes are highly fluffy in nature with voids and nanopores. Fourier transformed infrared (FTIR) spectrum shows the stearate ion co-ordinates with Zn2+ in the bidentate form. The surface properties such as surface free energy (γp) and work of adhesion (W) of the unmodified and modified ZnO coatings have been evaluated. The electron paramagnetic resonance (EPR) spectroscopy reveals that surface defects play a major role in the wetting behavior.

One-step synthesis and patterning of aligned polymer nanowires on a substrate

DOEpatents

Wang, Zhong L [Marietta, GA; Wang, Xudong [Atlanta, GA; Morber, Jenny R [Atlanta, GA; Liu, Jin [Danbury, CT

2011-11-08

In a method of making a polymer structure on a substrate a layer of a first polymer, having a horizontal top surface, is applied to a surface of the substrate. An area of the top surface of the polymer is manipulated to create an uneven feature that is plasma etched to remove a first portion from the layer of the first polymer thereby leaving the polymer structure extending therefrom. A light emitting structure includes a conductive substrate from which an elongated nanostructure of a first polymer extends. A second polymer coating is disposed about the nanostructure and includes a second polymer, which includes a material such that a band gap exists between the second polymer coating and the elongated nanostructure. A conductive material coats the second polymer coating. The light emitting structure emits light when a voltage is applied between the conductive substrate and the conductive coating.

Nano-coating of beta-galactosidase onto the surface of lactose by using an ultrasound-assisted technique.

PubMed

Genina, Natalja; Räikkönen, Heikki; Heinämäki, Jyrki; Veski, Peep; Yliruusi, Jouko

2010-06-01

We nano-coated powdered lactose particles with the enzyme beta-galactosidase using an ultrasound-assisted technique. Atomization of the enzyme solution did not change its activity. The amount of surface-attached beta-galactosidase was measured through its enzymatic reaction product D-galactose using a standardized method. A near-linear increase was obtained in the thickness of the enzyme coat as the treatment proceeded. Interestingly, lactose, which is a substrate for beta-galactosidase, did not undergo enzymatic degradation during processing and remained unchanged for at least 1 month. Stability of protein-coated lactose was due to the absence of water within the powder, as it was dry after the treatment procedure. In conclusion, we were able to attach the polypeptide to the core particles and determine precisely the coating efficiency of the surface-treated powder using a simple approach.

Self-healing effect of the protective inhibitor-containing coatings on Mg alloys

NASA Astrophysics Data System (ADS)

Gnedenkov, A. S.; Sinebryukhov, S. L.; Mashtalyar, D. V.; Gnedenkov, S. V.

2017-09-01

The method of self-healing coating formation on the surface of magnesium alloys on the base of plasma electrolytic oxidation (PEO) with subsequent impregnation of the obtained layer with inhibitor has been suggested. The protective and electrochemical properties of such coatings have been described. Localised Scanning Electrochemical Methods were used for determining the kinetics and mechanism of the self-healing process. The treatment with the solution containing inhibitor enables us to increase the protective properties of the PEO-coating in 30 times in the corrosion-active environment.

Synthesis of high T.sub.C superconducting coatings and patterns by melt writing and oxidation of metallic precursor alloys

DOEpatents

Gao, Wei; Vander Sande, John B.

1998-01-01

A method is provided for fabrication of superconducting oxides and superconducting oxide composites and for joining superconductors to other materials. A coating of a molten alloy containing the metallic elements of the oxide is applied to a substrate surface and oxidized to form the superconducting oxide. A material can be contacted to the molten alloy which is subsequently oxidized joining the material to the resulting superconducting oxide coating. Substrates of varied composition and shape can be coated or joined by this method.

Synthesis of high {Tc} superconducting coatings and patterns by melt writing and oxidation of metallic precursor alloys

DOEpatents

Gao, W.; Vander Sande, J.B.

1998-07-28

A method is provided for fabrication of superconducting oxides and superconducting oxide composites and for joining superconductors to other materials. A coating of a molten alloy containing the metallic elements of the oxide is applied to a substrate surface and oxidized to form the superconducting oxide. A material can be contacted to the molten alloy which is subsequently oxidized joining the material to the resulting superconducting oxide coating. Substrates of varied composition and shape can be coated or joined by this method. 5 figs.

Powder Metallurgy Reconditioning of Food and Processing Equipment Components

NASA Astrophysics Data System (ADS)

Nafikov, M. Z.; Aipov, R. S.; Konnov, A. Yu.

2017-12-01

A powder metallurgy method is developed to recondition the worn surfaces of food and processing equipment components. A combined additive is composed to minimize the powder losses in sintering. A technique is constructed to determine the powder consumption as a function of the required metallic coating thickness. A rapid method is developed to determine the porosity of the coating. The proposed technology is used to fabricate a wear-resistant defectless metallic coating with favorable residual stresses, and the adhesive strength of this coating is equal to the strength of the base metal.

Effect of disjoining pressure on terminal velocity of a bubble sliding along an inclined wall.

PubMed

Del Castillo, Lorena A; Ohnishi, Satomi; White, Lee R; Carnie, Steven L; Horn, Roger G

2011-12-15

The influence of salt concentration on the terminal velocities of gravity-driven single bubbles sliding along an inclined glass wall has been investigated, in an effort to establish whether surface forces acting between the wall and the bubble influence the latter's mobility. A simple sliding bubble apparatus was employed to measure the terminal velocities of air bubbles with radii ranging from 0.3 to 1.5 mm sliding along the interior wall of an inclined Pyrex glass cylinder with inclination angles between 0.6 and 40.1°. Experiments were performed in pure water, 10 mM and 100 mM KCl solutions. We compared our experimental results with a theory by Hodges et al. which considers hydrodynamic forces only, and with a theory developed by two of us which considers surface forces to play a significant role. Our experimental results demonstrate that the terminal velocity of the bubble not only varies with the angle of inclination and the bubble size but also with the salt concentration, particularly at low inclination angles of ∼1-5°, indicating that double-layer forces between the bubble and the wall influence the sliding behavior. This is the first demonstration that terminal velocities of sliding bubbles are affected by disjoining pressure. Copyright © 2011 Elsevier Inc. All rights reserved.

Simulation and evaluation of rupturable coated capsules by finite element method.

PubMed

Yang, Yan; Fang, Jie; Shen, Lian; Shan, Weiguang

2017-03-15

The objective of this study was to simulate and evaluate the burst behavior of rupturable coated capsules by finite element method (FEM). Film and coated capsules were prepared by dip-coating method and their dimensions were determined by stereomicroscope. Mechanical properties of the film were measured by tensile test and used as material properties of FEM models. Swelling pressure was determined by restrained expansion method and applied to the internal surface of FEM models. Water uptake of coated capsules was determined to study the formation of internal pressure. Burst test and in vitro dissolution was used to verify the FEM models, which were used to study and predict the coating burst behavior. Simulated results of coating burst behavior were well agreed with the experiment results. Swelling pressure, material properties and dimensions of coating had influence on the maximum stress. Burst pressure and critical L-HPC content were calculated for burst prediction and formulation optimization. FEM simulation was a feasible way to simulate and evaluate the burst behavior of coated capsules. Copyright © 2017 Elsevier B.V. All rights reserved.

Formation of a hydrophobic and corrosion resistant coating on magnesium alloy via a one-step hydrothermal method.

PubMed

Zheng, Tianxu; Hu, Yaobo; Zhang, Yuxin; Pan, Fusheng

2017-11-01

A hydrophobic coating was fabricated on the surface of magnesium alloy using a simple one-step hydrothermal method with the use of environmentally friendly agent. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and contact angle test were used to characterize the surfaces. Corrosion behavior in a 3.5wt.% NaCl solution was evaluated using OCP time curves test, potentiodynamic polarization test and EIS analysis. The findings show that the substrate is covered by the coating of magnesium hydroxide and magnesium stearate, reaching a contact angle of around 146°. Corrosion behavior show huge improvement, the progress with increase of treatment time could be related to the increased growth rate of coating. Copyright © 2017 Elsevier Inc. All rights reserved.

A highly precise frequency-based method for estimating the tension of an inclined cable with unknown boundary conditions

NASA Astrophysics Data System (ADS)

Ma, Lin

2017-11-01

This paper develops a method for precisely determining the tension of an inclined cable with unknown boundary conditions. First, the nonlinear motion equation of an inclined cable is derived, and a numerical model of the motion of the cable is proposed using the finite difference method. The proposed numerical model includes the sag-extensibility, flexural stiffness, inclination angle and rotational stiffness at two ends of the cable. Second, the influence of the dynamic parameters of the cable on its frequencies is discussed in detail, and a method for precisely determining the tension of an inclined cable is proposed based on the derivatives of the eigenvalues of the matrices. Finally, a multiparameter identification method is developed that can simultaneously identify multiple parameters, including the rotational stiffness at two ends. This scheme is applicable to inclined cables with varying sag, varying flexural stiffness and unknown boundary conditions. Numerical examples indicate that the method provides good precision. Because the parameters of cables other than tension (e.g., the flexural stiffness and rotational stiffness at the ends) are not accurately known in practical engineering, the multiparameter identification method could further improve the accuracy of cable tension measurements.

Characteristics of hydroxyapatite coated titanium porous coatings on Ti-6Al-4V substrates by plasma sprayed method.

PubMed

Yang, C Y; Chen, C R; Chang, E; Lee, T M

2007-08-01

A porous metal coating applied to solid substrate implants has been shown, in vivo, to anchor implants by bone ingrowth. Calcium phosphate ceramics, in particular hydroxyapatite [Ca(10)(PO(4))(6)(OH)(2), HA], are bioactive ceramics, which are known to be biocompatible and osteoconductive, and these ceramics deposited on to porous-coated devices may enhance bone ingrowth and implant fixation. In this study, bi-feedstock of the titanium powder and composite (Na(2)CO(3)/HA) powder were simultaneously deposited on a Ti-6Al-4V substrate by a plasma sprayed method. At high temperature of plasma torch, the solid state of Na(2)CO(3) would decompose to release CO(2) gas and then eject the molten Ti powder to induce the interconnected pores in the coatings. After cleaning and soaking in deionized water, the residual Na(2)CO(3) in the coating would dissolve to form the open pores, and the HA would exist at the surface of pores in the inner coatings. By varying the particle size of the composite powder, the porosity of porous coating could be varied from 25.0 to 34.0%, and the average pore size of the porous coating could be varied to range between 158.5 and 202.0 microm. Using a standard adhesive test (ASTM C-633), the bonding strength of the coating is between 27.3 and 38.2 MPa. By SEM, the HA was observed at the surface of inner pore in the porous coating. These results suggest that the method exhibits the potential to manufacture the bioactive ceramics on to porous-coated specimen to achieve bone ingrowth fixation for biomedical applications.

PRECISE TULLY-FISHER RELATIONS WITHOUT GALAXY INCLINATIONS

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

Obreschkow, D.; Meyer, M.

2013-11-10

Power-law relations between tracers of baryonic mass and rotational velocities of disk galaxies, so-called Tully-Fisher relations (TFRs), offer a wealth of applications in galaxy evolution and cosmology. However, measurements of rotational velocities require galaxy inclinations, which are difficult to measure, thus limiting the range of TFR studies. This work introduces a maximum likelihood estimation (MLE) method for recovering the TFR in galaxy samples with limited or no information on inclinations. The robustness and accuracy of this method is demonstrated using virtual and real galaxy samples. Intriguingly, the MLE reliably recovers the TFR of all test samples, even without using anymore » inclination measurements—that is, assuming a random sin i-distribution for galaxy inclinations. Explicitly, this 'inclination-free MLE' recovers the three TFR parameters (zero-point, slope, scatter) with statistical errors only about 1.5 times larger than the best estimates based on perfectly known galaxy inclinations with zero uncertainty. Thus, given realistic uncertainties, the inclination-free MLE is highly competitive. If inclination measurements have mean errors larger than 10°, it is better not to use any inclinations than to consider the inclination measurements to be exact. The inclination-free MLE opens interesting perspectives for future H I surveys by the Square Kilometer Array and its pathfinders.« less

Inclination shallowing in Eocene Linzizong sedimentary rocks from Southern Tibet: correction, possible causes and implications for reconstructing the India-Asia collision

NASA Astrophysics Data System (ADS)

Huang, Wentao; Dupont-Nivet, Guillaume; Lippert, Peter C.; van Hinsbergen, Douwe J. J.; Hallot, Erwan

2013-09-01

A systematic bias towards low palaeomagnetic inclination recorded in clastic sediments, that is, inclination shallowing, has been recognized and studied for decades. Identification, understanding and correction of this inclination shallowing are critical for palaeogeographic reconstructions, particularly those used in climate models and to date collisional events in convergent orogenic systems, such as those surrounding the Neotethys. Here we report palaeomagnetic inclinations from the sedimentary Eocene upper Linzizong Group of Southern Tibet that are ˜20° lower than conformable underlying volcanic units. At face value, the palaeomagnetic results from these sedimentary rocks suggest the southern margin of Asia was located ˜10°N, which is inconsistent with recent reviews of the palaeolatitude of Southern Tibet. We apply two different correction methods to estimate the magnitude of inclination shallowing independently from the volcanics. The mean inclination is corrected from 20.5° to 40.0° within 95 per cent confidence limits between 33.1° and 49.5° by the elongation/inclination (E/I) correction method; an anisotropy-based inclination correction method steepens the mean inclination to 41.3 ± 3.3° after a curve fitting- determined particle anisotropy of 1.39 is applied. These corrected inclinations are statistically indistinguishable from the well-determined 40.3 ± 4.5º mean inclination of the underlying volcanic rocks that provides an independent check on the validity of these correction methods. Our results show that inclination shallowing in sedimentary rocks can be corrected. Careful inspection of stratigraphic variations of rock magnetic properties and remanence anisotropy suggests shallowing was caused mainly by a combination of syn- and post-depositional processes such as particle imbrication and sedimentary compaction that vary in importance throughout the section. Palaeolatitudes calculated from palaeomagnetic directions from Eocene sedimentary rocks of the upper Linzizong Group that have corrected for inclination shallowing are consistent with palaeolatitude history of the Lhasa terrane, and suggest that the India-Asia collision began at ˜20°N by 45-55 Ma.

Inclined monochromator for high heat-load synchrotron x-ray radiation

DOEpatents

Khounsary, A.M.

1994-02-15

A double crystal monochromator is described including two identical, parallel crystals, each of which is cut such that the normal to the diffraction planes of interest makes an angle less than 90 degrees with the surface normal. Diffraction is symmetric, regardless of whether the crystals are symmetrically or asymmetrically cut, enabling operation of the monochromator with a fixed plane of diffraction. As a result of the inclination of the crystal surface, an incident beam has a footprint area which is elongated both vertically and horizontally when compared to that of the conventional monochromator, reducing the heat flux of the incident beam and enabling more efficient surface cooling. Because after inclination of the crystal only a fraction of thermal distortion lies in the diffraction plane, slope errors and the resultant misorientation of the diffracted beam are reduced. 11 figures.

Inclined monochromator for high heat-load synchrotron x-ray radiation

DOEpatents

Khounsary, Ali M.

1994-01-01

A double crystal monochromator including two identical, parallel crystals, each of which is cut such that the normal to the diffraction planes of interest makes an angle less than 90 degrees with the surface normal. Diffraction is symmetric, regardless of whether the crystals are symmetrically or asymmetrically cut, enabling operation of the monochromator with a fixed plane of diffraction. As a result of the inclination of the crystal surface, an incident beam has a footprint area which is elongated both vertically and horizontally when compared to that of the conventional monochromator, reducing the heat flux of the incident beam and enabling more efficient surface cooling. Because after inclination of the crystal only a fraction of thermal distortion lies in the diffraction plane, slope errors and the resultant misorientation of the diffracted beam are reduced.

Real-time monitoring of laser welding of galvanized high strength steel in lap joint configuration

NASA Astrophysics Data System (ADS)

Kong, Fanrong; Ma, Junjie; Carlson, Blair; Kovacevic, Radovan

2012-10-01

Two different cases regarding the zinc coating at the lap joint faying surface are selected for studying the influence of zinc vapor on the keyhole dynamics of the weld pool and the final welding quality. One case has the zinc coating fully removed at the faying surface; while the other case retains the zinc coating on the faying surface. It is found that removal of the zinc coating at the faying surface produces a significantly better weld quality as exemplified by a lack of spatters whereas intense spatters are present when the zinc coating is present at the faying surface. Spectroscopy is used to detect the optical spectra emitted from a laser generated plasma plume during the laser welding of galvanized high strength DP980 steel in a lap-joint configuration. A correlation between the electron temperature and defects within the weld bead is identified by using the Boltzmann plot method. The laser weld pool keyhole dynamic behavior affected by a high-pressure zinc vapor generated at the faying surface of galvanized steel lap-joint is monitored in real-time by a high speed charge-coupled device (CCD) camera assisted with a green laser as an illumination source.

Hydroxyapatite crystals biologically inspired on titanium by using an organic template based on the copolymer of acrylic acid and itaconic acid.

PubMed

Zhang, Chao; Li, Zhi-An; Cheng, Xiang-Rong; Xiao, Qun; Li, Hong-Bo

2010-01-01

Hydroxyapatite coating on metal implants is an effective method to enhance bioactive properties of the metal surface. We report here a method to coat the Ti-6Al-4V alloy with hydroxyapatite crystals. After alkaline/heat treatment, the spontaneous growth of organoapatite on titanium alloy surface involves sequential preadsorption of titanium isopropoxide (TIPO) and the copolymer of acrylic acid and itaconic acid on the metal, followed by exposure to simulated body fluid (SBF). The organoapatite characterization of the coating was carried out by scanning electron microscopy, energy dispersive spectrometer, and X-ray diffraction. The copolymer of acrylic acid and itaconic acid overlayer which is rich of carboxylate groups can lead to the deposition of needle-like and homogeneous HA on the surface after immersion in SBF.

Coated substrate apparatus and method

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

Bao, Zhenan; Diao, Ying; Mannsfeld, Stefan Christian Bernhardt

A coated substrate is formed with aligned objects such as small molecules, macromolecules and nanoscale particulates, such as inorganic, organic or inorganic/organic hybrid materials. In accordance with one or more embodiments, an apparatus or method involves an applicator having at least one surface patterned with protruded or indented features, and a coated substrate including a solution-based layer of objects having features and morphology attributes arranged as a function of the protruded or indented features.

Thermal behavior and catalytic activity in naphthalene destruction of Ce-, Zr- and Mn-containing oxide layers on titanium

NASA Astrophysics Data System (ADS)

Vasilyeva, Marina S.; Rudnev, Vladimir S.; Wiedenmann, Florian; Wybornov, Svetlana; Yarovaya, Tatyana P.; Jiang, Xin

2011-11-01

The present paper is devoted to studies of the composition and surface structure, including those after annealing at high temperatures, and catalytic activity in the reaction of naphthalene destruction of Ce-, Zr- and Mn-containing oxide layers on titanium obtained by means of the plasma electrolytic oxidation (PEO) method. The composition and structure of the obtained systems were investigated using the methods of X-ray phase and energy dispersive analysis and scanning electron microscopy (SEM). It was demonstrated that Ce- and Zr- containing structures had relatively high thermal stability: their element and phase compositions and surface structure underwent virtually no changes after annealing in the temperature range 600-800 °C. Annealing of Ce- and Zr-containing coatings in the temperature range 850-900 °C resulted in substantial changes of their surface composition and structure: a relatively homogeneous and porous surface becomes coated by large pole-like crystals. The catalytic studies showed rather high activity of Ce- and Zr-containing coatings in the reaction of naphthalene destruction at temperatures up to 850 °C. Mn-containing structures of the type MnOx + SiO2 + TiO2/Ti have a well-developed surface coated by “nano-whiskers”. The phase composition and surface structure of manganese-containing layers changes dramatically in the course of thermal treatment. After annealing above 600 °C nano-whiskers vanish with formation of molten structures on the surface. The Mn-containing oxide systems demonstrated lower conversion degrees than the Ce- and Zr-containing coatings, which can be attributed to substantial surface modification and formation of molten manganese silicates at high temperatures.

Improved water resistance of SrAl2O4: Eu2+, Dy3+ phosphor directly achieved in a water-containing medium

NASA Astrophysics Data System (ADS)

Qi, Tonggang; Xia, Haofu; Zhang, Zhanhui; Kong, Shijin; Peng, Weikang; Zhao, Qi; Huang, Zhiliang

2017-03-01

In this paper, a heterogeneous precipitation method utilizing urea hydrolysis was adopted to coat a SiO2 layer on the surface of SrAl2O4:Eu2+, Dy3+ long persistence phosphors. To avoid phosphor hydrolysis in a water-containing coating medium, the hydrolysis and polymerization reactions of tetraethyl orthosilicate (TEOS) were concerned and carried out. The crystal phases, surface morphologies, hydrolysis stability and water resistance on afterglow properties of coated phosphors were investigated. Scanning electron microscopy, energy dispersive spectrum analysis, transmission electron microscope and Fourier transform infrared spectrum results confirmed that a continuous, uniform and compact SiO2 coating layer was successfully obtained on the phosphors surface. A theoretical coating amount of 5% or higher was found to be good for hydrolysis stability. Photoluminescence results revealed the coated phosphors showed much better water resistance on afterglow properties than the uncoated phosphor. We also discussed and proposed the hydrolysis restriction mechanism of SrAl2O4:Eu2+, Dy3+ in the water-containing coating medium.

Deposition of Hydroxyapatite Onto Superelastic Nitinol Using an Ambient Temperature Blast Coating Process

NASA Astrophysics Data System (ADS)

Dunne, Conor F.; Roche, Kevin; Ruddy, Mark; Doherty, Kevin A. J.; Twomey, Barry; O'Donoghue, John; Hodgson, Darel; Stanton, Kenneth T.

2018-06-01

This work investigates the deposition of hydroxyapatite (HA) onto superelastic nickel-titanium (NiTi) using an ambient temperature coating process known as CoBlast. The process utilises a stream of abrasive alumina (Al2O3) and a coating medium (HA) sprayed simultaneously at the surface of the substrate. The use of traditional coatings methods, such as plasma spray, is unsuitable due to the high temperatures of the process. This can result in changes to both the crystallinity of the HA and properties of the thermally sensitive NiTi. HA is a biocompatible, biodegradable and osteoconductive ceramic, which when used as a coating can promote bone growth and prevent the release of nickel from NiTi in vivo. Samples were coated using different blast pressures and abrasive particle sizes and were examined using a variety of techniques. The coated samples had a thin adherent coating, which increased in surface roughness and coating thickness with increasing abrasive particle size. X-ray diffraction analysis revealed that the process gave rise to a stress-induced martensite phase in the NiTi which may enhance mechanical properties. The study indicates that the CoBlast process can be used to deposit thin adherent coatings of HA onto the surface of superelastic NiTi.

Evaluation of long-term corrosion durability and self-healing ability of scratched coating systems on carbon steel in a marine environment

NASA Astrophysics Data System (ADS)

Zhao, Xia; Chen, Changwei; Xu, Weichen; Zhu, Qingjun; Ge, Chengyue; Hou, Baorong

2017-09-01

Defects in protective-coating systems on steel surfaces are inevitable in practical engineering applications. A composite coating system, including a primer, middle coat and topcoat, were used to protect carbon steel from corrosion in a marine environment. Two environmental additives, glass fibers and thiourea, were applied in the middle coat to modify the coating system. The long-term corrosion durability and self-healing ability of the scratched coating system were evaluated by multiple methods. Results of the electrochemical technologies indicated that the coating system that contained 0.5 wt.% fibers and 0.5 wt.% thiourea presented good corrosion protection and self-healing for carbon steel when immersed in 3.5% NaCl for 120 d. Evolution of localized corrosion factors with time, as obtained from the current distribution showed that fibers combined with thiourea could inhibit the occurrence of local corrosion in scratched coating systems and retarded the corrosion development significantly. Surface characterization suggested that adequate thiourea could be absorbed uniformly on fibers for a long time to play an important role in protecting the carbon steel. Finally, schematic models were established to demonstrate the action of fibers and thiourea on the exposed surface of the carbon steel and the scratched coating system in the entire deterioration process.

Formation of Microcracks During Micro-Arc Oxidation in a Phytic Acid-Containing Solution on Two-Phase AZ91HP

NASA Astrophysics Data System (ADS)

Zhang, R. F.; Chang, W. H.; Jiang, L. F.; Qu, B.; Zhang, S. F.; Qiao, L. P.; Xiang, J. H.

2016-04-01

Micro-arc oxidation (MAO) is an effective method to produce ceramic coatings on magnesium alloys and can considerably improve their corrosion resistance. The coating properties are closely related with microcracks, which are always inevitably developed on the coating surface. In order to find out the formation and development regularity of microcracks, anodic coatings developed on two-phase AZ91HP after different anodizing times were fabricated in a solution containing environmentally friendly organic electrolyte phytic acid. The results show that anodic film is initially developed on the α phase. At 50 s, anodic coatings begin to develop on the β phase, evidencing the formation of a rough area. Due to the coating successive development, the microcracks initially appear at the boundary between the initially formed coating on the α phase and the subsequently developed coating on the β phase. With the prolonging treatment time, the microcracks near the β phase become evident. After treating for 3 min, the originally rough area on the β phase disappears and the coatings become almost uniform with microcracks randomly distributed on the sample surface. Inorganic phosphates are found in MAO coatings, suggesting that phytate salts are decomposed due to the high instantaneous temperature on the sample surface resulted from spark discharge.

Enhanced performance of graphite anode materials by AlF3 coating for lithium-ion batteries

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

Ding, Fei; Xu, Wu; Choi, Daiwon

2012-04-27

In order to form the stable surface film and to further enhance the long-term cycling stability of the graphite anodes of lithium-ion batteries, the surface of graphite powders has been modified by AlF3 coating through chemical precipitation method. The AlF3-coated graphite shows no evident changes in the bulk structure and a thin AlF3-coating layer of about 2 nm thick is found to uniformly cover the graphite particles with 2 wt% AlF3 content. However, it delivers a higher initial discharge capacity and largely improved rate performances compared to the pristine graphite. Remarkably, AlF3 coated graphite demonstrated a much better cycle life.more » After 300 cycles, AlF3 coated graphite and uncoated graphite show capacity retention of 92% and 81%, respectively. XPS measurement shows that a more conductive solid electrode interface (SEI) layer was formed on AlF3 coated graphite as compared to uncoated graphite. SEM monograph also reveals that the AlF3-coated graphite particles have a much more stable surface morphology after long-term cycling. Therefore, the improved electrochemical performance of AlF3 coated graphite can be attributed to a more stable and conductive SEI formed on coated graphite anode during cycling process.« less

Effect of Coating Thickness on the Properties of TiN Coatings Deposited on Tool Steels Using Cathodic Arc Pvd Technique

NASA Astrophysics Data System (ADS)

Mubarak, A.; Akhter, Parvez; Hamzah, Esah; Mohd Toff, Mohd Radzi Hj.; Qazi, Ishtiaq A.

Titanium nitride (TiN) widely used as hard coating material, was coated on tool steels, namely on high-speed steel (HSS) and D2 tool steel by physical vapor deposition method. The study concentrated on cathodic arc physical vapor deposition (CAPVD), a technique used for the deposition of hard coatings for tooling applications, and which has many advantages. The main drawback of this technique, however, is the formation of macrodroplets (MDs) during deposition, resulting in films with rougher morphology. Various standard characterization techniques and equipment, such as electron microscopy, atomic force microscopy, hardness testing machine, scratch tester, and pin-on-disc machine, were used to analyze and quantify the following properties and parameters: surface morphology, thickness, hardness, adhesion, and coefficient of friction (COF) of the deposited coatings. Surface morphology revealed that the MDs produced during the etching stage, protruded through the TiN film, resulting in film with deteriorated surface features. Both coating thickness and indentation loads influenced the hardness of the deposited coatings. The coatings deposited on HSS exhibit better adhesion compared to those on D2 tool steel. Standard deviation indicates that the coating deposited with thickness around 6.7 μm showed the most stable trend of COF versus sliding distance.

Random Surface Texturing of Silicon Dioxide Using Gold Agglomerates

DTIC Science & Technology

2016-07-01

Approved for public release; distribution unlimited. 1 1. Introduction The US Army has been developing new types of photovoltaic ( PV ) devices— solar ...light falling onto the surface of a solar cell is a major optical loss mechanism, which limits the efficiency of the PV .1,2 One method of reducing...in an AR coating on solar cells. 15. SUBJECT TERMS anti-reflective, AR coatings, textured surface structures, silicon dioxide, SiO2 16. SECURITY

Effect of Surface Modification on Corrosion Resistance of Uncoated and DLC Coated Stainless Steel Surface

NASA Astrophysics Data System (ADS)

Scendo, Mieczyslaw; Staszewska-Samson, Katarzyna

2017-08-01

Corrosion resistance of 4H13 stainless steel (EN-X46Cr13) surface uncoated and coated with an amorphous hydrogenated carbon (a-C:H) film [diamond-like carbon (DLC)] in acidic chloride solution was investigated. The DLC films were deposited on steel surface by a plasma deposition, direct current discharge (PDCD) method. The Fourier transform infrared (FTIR) was used to determine the chemical groups existing on DLC films. The surface of the specimens was observed by a scanning electron microscope (SEM). The tribological properties of the both materials were examined using a ball-on disk tribometer. The microhardness (HV) of diamond-like carbon film increased over five times in relation to the 4H13 stainless steel without of DLC coating. Oxidation kinetic parameters were determined by gravimetric and electrochemical methods. The high value of polarization resistance indicates that the DLC film on substrate was characterized by low electrical conductivity. The corrosion rate of 4H13 stainless steel with of DLC film decreased about eight times in relation to uncoated surface of 4H13 stainless steel.

Interaction of carbon nanotubes coatings with titanium substrate

NASA Astrophysics Data System (ADS)

Fraczek-Szczypta, Aneta; Wedel-Grzenda, Alicja; Benko, Aleksandra; Grzonka, Justyna; Mizera, Jaroslaw

2017-02-01

The aim of this study was to evaluate the impact of multi-walled carbon nanotubes (MWCNTs) after chemical surface functionalization on the interaction with a titanium surface. Two kinds of MWCNTs differing in terms of concentration of functional groups were deposited on the Ti surface using the electrophoretic deposition method (EPD). The study has shown the detailed analysis of the physicochemical properties of this form of carbon nanomaterial and received on their base coatings using various techniques, such as scanning electron microscopy (SEM), confocal microscopy, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The adhesion of the MWCNTs coatings to the Ti surface was determined using the shear test method, according to standard ASTM F-1044-05. These results indicated that one type of MWCNTs characterized by a higher concentration of functional groups has better adhesion to the metal surface than the second type. Analysis of the MWCNT-metal interface using Raman spectroscopy and SEM and STEM indicates the presence of phase built of MWCNT and TiO2. This phase could be a type of nanocomposite that affects the improvement of the adhesion of MWCNT to the Ti surface.

Method for providing mirror surfaces with protective strippable polymeric film

DOEpatents

Edwards, Charlene C.; Day, Jack R.

1980-01-01

This invention is a method for forming a protective, strippable, elastomeric film on a highly reflective surface. The method is especially well suited for protecting diamond-machined metallic mirrors, which are susceptible not only to abrasion and mechanical damage but also to contamination and corrosion by various fluids. In a typical use of the invention, a diamond-machined copper mirror surface is coated uniformly with a solution comprising a completely polymerized and completely cured thermoplastic urethane elastomer dissolved in tetrahydrofuran. The applied coating is evaporated to dryness, forming a tough, adherent, impermeable, and transparent film which encapsulates dust and other particulates on the surface. The film may be left in place for many months. When desired, the film may be stripped intact, removing the entrapped particulates and leaving no residue on the mirror surface.

A review of various nozzle range of wire arc spray on FeCrBMnSi metal coating

NASA Astrophysics Data System (ADS)

Purwaningsih, Hariyati; Rochiem, Rochman; Suchaimi, Muhammad; Jatimurti, Wikan; Wibisono, Alvian Toto; Kurniawan, Budi Agung

2018-04-01

Low Temperature Hot Corrosion (LTHC) is type of hot corrosion which occurred on 700-800°C and usually on turbine blades. So, as a result the material of turbine blades is crack and degredation of rotation efficiency. Hot corrosion protection with the use of barrier that separate substrate and environment is one of using metal surface coating, wire arc spray method. This study has a purpose to analyze the effect of nozzle distance and gas pressure on FeCrBMnSi coating process using wire arc spray method on thermal resistance. The parameter of nozzle distance and gas pressure are used, resulted the best parameter on distance 400 mm and gas pressure 3 bar which has the bond strength of 12,58 MPa with porosity percentage of 5,93% and roughness values of 16,36 µm. While the examination of thermal cycle which by heating and cooling continuously, on the coating surface is formed oxide compound (Fe3O4) which cause formed crack propagation and delamination. Beside that hardness of coating surface is increase which caused by precipitate boride (Fe9B)0,2

Fiber optic inclination detector system having a weighted sphere with reference points

DOEpatents

Cwalinski, Jeffrey P.

1995-01-01

A fiber optic inclination detector system for determining the angular displacement of an object from a reference surface includes a simple mechanical transducer which requires a minimum number of parts and no electrical components. The system employs a single light beam which is split into two light beams and provided to the transducer. Each light beam is amplitude modulated upon reflecting off the transducer to detect inclination. The power values associated with each of the reflected light beams are converted by a pair of photodetectors into voltage signals, and a microprocessor manipulates the voltage signals to provide a measure of the angular displacement between the object and the reference surface.

Diagnostics of transparent polymer coatings of metal items

NASA Astrophysics Data System (ADS)

Varepo, L. G.; Ermakova, I. N.; Nagornova, I. V.; Kondratov, A. P.

2017-08-01

The methods of visual and instrumental express diagnostics of safety critical defects and non-uniform thickness of transparent mono- and multilayer polyolefin surface coating of metal items are analyzed in the paper. The instrumental diagnostics method relates to colorimetric measuring based on effects, which appear in the polarized light for extrusion polymer coatings. A color coordinates dependence (in the color system CIE La*b*) on both HDPE / PVC coating thickness fluctuation values (from average ones) and coating interlayer or adhesion layer delaminating is shown. A variation of color characteristics in the polarized light at a liquid penetration into delaminated polymer layers is found. Measuring parameters and critical uncertainties are defined.

Structure of electroexplosive TiC-Ni composite coatings on steel after electron-beam treatment

NASA Astrophysics Data System (ADS)

Romanov, D. A.; Goncharova, E. N.; Budovskikh, E. A.; Gromov, V. E.; Ivanov, Yu. F.; Teresov, A. D.; Kazimirov, S. A.

2016-11-01

The phase and elemental compositions of the surface layer in Hardox 450 steel after electroexplosive spraying of a TiC-Ni composite coating and subsequent irradiation by a submillisecond high-energy electron beam are studied by the methods of modern physical metallurgy. The electron-beam treatment conditions that result in the formation of dense surface layers having high luster and a submicrocrystalline structure based on titanium carbide and nickel are found. It is shown that electron-beam treatment of an electroexplosive coating performed under melting conditions leads to the formation of a homogeneous (in structure and concentration) surface layer.

Transverse depth-dependent changes in corneal collagen lamellar orientation and distribution

PubMed Central

Abass, Ahmed; Hayes, Sally; White, Nick; Sorensen, Thomas; Meek, Keith M.

2015-01-01

It is thought that corneal surface topography may be stabilized by the angular orientation of out-of plane lamellae that insert into the anterior limiting membrane. In this study, micro-focus X-ray scattering data were used to obtain quantitative information about lamellar inclination (with respect to the corneal surface) and the X-ray scatter intensity throughout the depth of the cornea from the centre to the temporal limbus. The average collagen inclination remained predominantly parallel to the tissue surface at all depths. However, in the central cornea, the spread of inclination angles was greatest in the anterior-most stroma (reflecting the increased lamellar interweaving in this region), and decreased with tissue depth; in the peripheral cornea inclination angles showed less variation throughout the tissue thickness. Inclination angles in the deeper stroma were generally higher in the peripheral cornea, suggesting the presence of more interweaving in the posterior stroma away from the central cornea. An increase in collagen X-ray scatter was identified in a region extending from the sclera anteriorly until about 2 mm from the corneal centre. This could arise from the presence of larger diameter fibrils, probably of scleral origin, which are known to exist in this region. Incorporation of this quantitative information into finite-element models will further improve the accuracy with which they can predict the biomechanical response of the cornea to pathology and refractive procedures. PMID:25631562

Droplet Depinning on Inclined Surfaces at High Reynolds Numbers

NASA Astrophysics Data System (ADS)

White, Edward; Singh, Natasha; Lee, Sungyon

2017-11-01

Contact angle hysteresis enables a sessile liquid drop to adhere to a solid surface when the surface is inclined, the drop is exposed to gas-phase flow, or the drop is exposed to both forcing modalities. Previous work by Schmucker and White (2012.DFD.M4.6) identified critical depinning Weber numbers for water drops subject to gravity- and wind-dominated forcing. This work extends the Schmucker and White data and finds the critical depinning Weber number obeys a two-slope linear model. Under pure wind forcing at Reynolds numbers above 1500 and with zero surface inclination, Wecrit = 8.0 . For non-zero inclinations, α, Wecrit decreases proportionally to A Bo sinα where A is the drop aspect ratio and Bo is its Bond number. The same relationship holds for α < 0 when gravity resists depinning by wind. Above We 4 , depinning is dominated by wind forcing; at We < 4 , depinning is gravity dominated. While Wecrit depends linearly on A Bo sinα in both forcing regimes, the slopes of the the limit lines depend on the forcing regime. The difference is attributed to different drop shapes and contact angle distributions that arise depending on whether wind or gravity dominates the depinning behavior. Supported by the National Science Foundation through Grant CBET-1605947.

A one-inch mirror is polished as part of nationwide student project for STARSHINE spacecraft

NASA Technical Reports Server (NTRS)

1999-01-01

The one-inch mirror shown here is one of nearly nine hundred polished by dozens of students teams of elementary, middle and high school students across the nation as part of STARSHINE, a student spacecraft built by the Naval Research Laboratory in Washington, D.C. After being coated with a protective transparent layer of Silicon Dioxide at Hill Air Force Base, they are being mounted on the surface of the spacecraft. STARSHINE is being deployed into a highly inclined low-earth orbit from a Hitchhiker canister on mission STS-96, targeted to launch May 20. After deployment from the Shuttle in May, the spacecraft will reflect flashes of sunlight to observers on the earth during the mission. This twinkling satellite will be naked-eye visible against the star background for about six months during recurring morning and evening twilight periods to student observers around the world.

Broadband optical radiation detector

NASA Technical Reports Server (NTRS)

Gupta, A.; Hong, S. D.; Moacanin, J. (Inventor)

1981-01-01

A method and apparatus for detecting optical radiation by optically monitoring temperature changes in a microvolume caused by absorption of the optical radiation to be detected is described. More specifically, a thermal lens forming material is provided which has first and second opposite, substantially parallel surfaces. A reflective coating is formed on the first surface, and a radiation absorbing coating is formed on the reflective coating. Chopped, incoming optical radiation to be detected is directed to irradiate a small portion of the radiation absorbing coating. Heat generated in this small area is conducted to the lens forming material through the reflective coating, thereby raising the temperature of a small portion of the lens forming material and causing a thermal lens to be formed therein.

Detection of anions by normal Raman spectroscopy and surface-enhanced Raman spectroscopy of cationic-coated substrates.

PubMed

Mosier-Boss, P A; Lieberman, S H

2003-09-01

The use of normal Raman spectroscopy and surface-enhanced Raman spectroscopy (SERS) of cationic-coated silver and gold substrates to detect polyatomic anions in aqueous environments is examined. For normal Raman spectroscopy, using near-infrared excitation, linear concentration responses were observed. Detection limits varied from 84 ppm for perchlorate to 2600 ppm for phosphate. In general, detection limits in the ppb to ppm concentration range for the polyatomic anions were achieved using cationic-coated SERS substrates. Adsorption of the polyatomic anions on the cationic-coated SERS substrates was described by a Frumkin isotherm. The SERS technique could not be used to detect dichromate, as this anion reacted with the coatings to form thiol esters. A competitive complexation method was used to evaluate the interaction of chloride ion with the cationic coatings. Hydrogen bonding and pi-pi interactions play significant roles in the selectivity of the cationic coatings.

Hydroxyapatite for Keratoprosthesis Biointegration

PubMed Central

Wang, Liqiang; Jeong, Kyung Jae; Chiang, Homer H.; Zurakowski, David; Behlau, Irmgard; Chodosh, James; Dohlman, Claes H.; Langer, Robert

2011-01-01

Purpose. Integration of keratoprosthesis with the surrounding cornea is very important in preventing bacterial invasion, which may cause ocular injury. Here the authors investigated whether hydroxyapatite (HAp) coating can improve keratoprosthesis (KPro) biointegration, using polymethyl methacrylate (PMMA)—the principal component of the Boston KPro—as a model polymer. Methods. HAp coatings were induced on PMMA discs after treatment with concentrated NaOH and coating with poly-dopamine (PDA) or polydopamine and then with 11-mercaptoundecanoic acid (11-MUA). Coatings were characterized chemically (Fourier transform infrared spectroscopy [FTIR], energy dispersive X-ray spectroscopy [EDX]) and morphologically (SEM) and were used as substrates for keratocyte growth in vitro. Cylinders of coated PMMA were implanted in porcine corneas ex vivo for 2 weeks, and the force required to pull them out was measured. The inflammatory reaction to coated discs was assessed in the rabbit cornea in vivo. Results. FTIR of the coatings showed absorption bands characteristic of phosphate groups, and EDX showed that the Ca/P ratios were close to those of HAp. By SEM, each method resulted in morphologically distinct HAp films; the 11-MUA group had the most uniform coating. The hydroxyapatite coatings caused comparable enhancement of keratocyte proliferation compared with unmodified PMMA surfaces. HAp coating significantly increased the force and work required to pull PMMA cylinders out of porcine corneas ex vivo. HAp coating of implants reduced the inflammatory response around the PMMA implants in vivo. Conclusions. These results are encouraging for the potential of HAp-coated surfaces for use in keratoprostheses. PMID:21849419

Graphene coatings for protection against microbiologically induced corrosion

NASA Astrophysics Data System (ADS)

Krishnamurthy, Ajay

Microbiologically induced corrosion (MIC) is a special form of electrochemical corrosion where micro-organisms affect the local environmental conditions at the metal-electrolyte interface by forming a stable biofilm. The biofilm introduces localized concentration cells, which accelerate the electrochemical corrosion rates. MIC has been found to affect many industrial systems such as sewage waste water pipes, heat exchangers, ships, underwater pipes etc. It has been traditionally eradicated by physical, biochemical and surface protection methods. The cleaning methods and the biocidal deliveries are required periodically and don't provide a permanent solution to the problem. Further, the use of biocides has been harshly criticized by environmentalists due to safety concerns associated with their usage. Surface based coatings have their own drawback of rapid degradation under harsh microbial environments. This has led to the exploration of thin, robust, inert, conformal passivation coatings for the protection of metallic surfaces from microbiologically induced corrosion. Graphene is a 2D arrangement of carbon atoms in a hexagonal honeycomb lattice. The carbon atoms are bonded to one another by sp2 hybridization and each layer of the carbon ring arrangement spans to a thickness of less than a nm. Due to its unique 2D arrangement of carbon atoms, graphene exhibits interesting in-plane and out of plane properties that have led to it being considered as the material for the future. Its excellent thermal, mechanical, electrical and optical properties are being explored in great depth to understand and realize potential applications in various technological realms. Early studies have shown the ability of bulk and monolayer graphene to protect metallic surfaces from air oxidation and solution based galvanic corrosion processes for short periods. However, the role of graphene in resisting MIC is yet to be determined, particularly over the long time spans characteristic of this form of corrosion. Chapter 1 introduces the basics of microbiologically induced corrosion and graphene. A comprehensive review of literature is used to discuss the role of micro-organisms, their impact on corrosion and their eradication. The conflicting results behind the use of graphene as a coating material are evaluated using the available literature and its future as an effective MIC resistant coating is then discussed. Chapter 2 is a study of the effectiveness of graphene based coatings for passivating metal surfaces against microbial induced corrosion. The effectiveness of graphene is evaluated against a bare metal electrode and a regular carbon based electrode using Cyclic Voltammetry (CV), Electrochemical Impedance Spectroscopy (EIS), Spectrophotometry and Scanning Electron Microscopy (SEM). Results indicate 3-orders-of-magnitude lower corrosion currents in the graphene coated electrode and about two orders of magnitude higher impedance to interfacial electrochemical reactions. After establishing the superiority of graphene over bare metal electrode, further studies were conducted to compare its performance over other state of the art polymer coatings such as parylene and polyurethane. This study is discussed in detail in Chapter 3. Quantitatively, graphene outperforms the polymer coated electrodes by offering close to two orders of magnitude higher MIC resistance, while qualitatively, optical images indicate severe oxidation in both the polymer coated metal structures. The chapter is concluded with discussions on the unparalleled corrosion resistance provided by graphene based coatings. The success/failure of coating techniques is not purely dictated by their ability to protect the surface, but also by the ease of coating application onto any given surface. Chapter 4 explains the methods by which high quality graphene can be used to protect surfaces that are not conducive to graphene growth and the problems associated with the current transfer techniques. A Raman Spectroscopy based surface mapping is performed to understand the defect peak intensities across the surface and the reasons for coating failure when using the state-of-the-art transfer techniques is discussed.

Transcriptional and computational study of expansins differentially expressed in response to inclination in radiata pine.

PubMed

Mateluna, Patricio; Valenzuela-Riffo, Felipe; Morales-Quintana, Luis; Herrera, Raúl; Ramos, Patricio

2017-06-01

Plants have the ability to reorient their vertical growth when exposed to inclination. This response can be as quick as 2 h in inclined young pine (Pinus radiata D. Don) seedlings, with over accumulation of lignin observed after 9 days s. Several studies have identified expansins involved in cell expansion among other developmental processes in plants. Six putative expansin genes were identified in cDNA libraries isolated from inclined pine stems. A differential transcript abundance was observed by qPCR analysis over a time course of inclination. Five genes changed their transcript accumulation in both stem sides in a spatial and temporal manner compared with non-inclined stem. To compare these expansin genes, and to suggest a possible mechanism of action at molecular level, the structures of the predicted proteins were built by comparative modeling methodology. An open groove on the surface of the proteins composed of conserved zresidues was observed. Using a cellulose polymer as ligand the protein-ligand interaction was evaluated, with the results showing differences in the protein-ligand interaction mode. Differences in the binding energy interaction can be explained by changes in some residues that generate differences in electrostatic surface in the open groove region, supporting the participation of six members of multifamily proteins in this specific process. The data suggests participation of different expansin proteins in the dissembling and remodeling of the complex cell wall matrix during the reorientation response to inclination. Copyright © 2017 Elsevier Masson SAS. All rights reserved.