CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING SURFACE WIPE FOR ANALYSIS OF NEUTRAL PERSISTENT ORGANIC POLLUTANTS (SOP-5.17)

EPA Science Inventory

This SOP summarizes the method for extracting and preparing a hard floor surface wipe or food preparation surface wipe sample for analysis of neutral persistent organic. It covers the extraction and concentration of samples that are to be analyzed by gas chromatography/mass spect...

Microporous structure with layered interstitial surface treatment, and method and apparatus for preparation thereof

NASA Technical Reports Server (NTRS)

Koontz, Steven L. (Inventor)

1994-01-01

A microporous structure with layered interstitial surface treatments, and method and apparatus for preparation thereof is presented. The structure is prepared by sequentially subjecting a uniformly surface-treated structure to atomic oxygen treatment to remove an outer layer of surface treatment to a generally uniform depth, and then surface treating the so exposed layer with another surface treating agent. The atomic oxygen/surface treatment steps may optionally be repeated, each successive time to a lesser depth, to produce a microporous structure having multilayered surface treatments. The apparatus employs at least one side arm from a main atomic oxygen-containing chamber. The side arm has characteristic relaxation times such that a uniform atomic oxygen dose rate is delivered to a specimen positioned transversely in the side arm spaced from the main gas chamber.

Microporous structure with layered interstitial surface treatment, and method and apparatus for preparation thereof

NASA Technical Reports Server (NTRS)

Koontz, Steven L. (Inventor)

1992-01-01

A microporous structure with layered interstitial surface treatments, and the method and apparatus for its preparation are disclosed. The structure is prepared by sequentially subjecting a uniformly surface treated structure to atomic oxygen treatment to remove an outer layer of surface treatment to a generally uniform depth, and then surface treating the so exposed layer with another surface treating agent. The atomic oxygen/surface treatment steps may optionally be repeated, each successive time to a lesser depth, to produce a microporous structure having multilayered surface treatments. The apparatus employs at least one side arm from a main oxygen-containing chamber. The side arm has characteristic relaxation times such that a uniform atomic oxygen dose rate is delivered to a specimen positioned transversely in the side arm spaced from the main gas chamber.

Studies on wettability of polypropylene/methyl-silicone composite film and polypropylene monolithic material.

PubMed

Hou, Weixin; Mu, Bo; Wang, Qihua

2008-11-01

A polypropylene/methyl-silicone superhydrophobic surface was prepared using a simple casting method. Varying the ratio of polypropylene and methyl-silicone results in different surface microstructure. The wetting behavior of the as-prepared surface was investigated. A polypropylene monolithic material was also prepared. Its superhydrophobicity still retains when the material was cut or abraded. The as-prepared material can also be used to separate some organic solvents from water.

Methods and apparatuses for preparing a surface to have catalytic activity

DOEpatents

Cooks, Robert G [West Lafayette, IN; Peng, Wen-Ping [West Lafayette, IN; Ouyang, Zheng [West Lafayette, IN; Goodwin, Michael P [West Lafayette, IN

2011-03-22

The invention provides methods and apparatuses that utilize mass spectrometry for preparation of a surface to have catalytic activity through molecular soft-landing of mass selected ions. Mass spectrometry is used to generate combinations of atoms in a particular geometrical arrangement, and ion soft-landing selects this molecular entity or combination of entities and gently deposits the entity or combination intact onto a surface.

Ice Surfaces.

PubMed

Shultz, Mary Jane

2017-05-05

Ice is a fundamental solid with important environmental, biological, geological, and extraterrestrial impact. The stable form of ice at atmospheric pressure is hexagonal ice, I h . Despite its prevalence, I h remains an enigmatic solid, in part due to challenges in preparing samples for fundamental studies. Surfaces of ice present even greater challenges. Recently developed methods for preparation of large single-crystal samples make it possible to reproducibly prepare any chosen face to address numerous fundamental questions. This review describes preparation methods along with results that firmly establish the connection between the macroscopic structure (observed in snowflakes, microcrystallites, or etch pits) and the molecular-level configuration (detected with X-ray or electron scattering techniques). Selected results of probing interactions at the ice surface, including growth from the melt, surface vibrations, and characterization of the quasi-liquid layer, are discussed.

Shear-bond-strength of orthodontic brackets to aged nano-hybrid composite-resin surfaces using different surface preparation.

PubMed

Demirtas, Hatice Kubra; Akin, Mehmet; Ileri, Zehra; Basciftci, Faruk Ayhan

2015-01-01

The aim of this study was to evaluate the effects of different surface preparation methods on the shear bond strength (SBS) of orthodontic metal brackets to aged nano-hybrid resin composite surfaces in vitro. A total of 100 restorative composite resin discs, 6 mm in diameter and 3 mm thick, were obtained and treated with an ageing procedure. After ageing, the samples were randomly divided as follows according to surface preparation methods: (1)Control, (2)37% phosphoric acid gel, (3)Sandblasting, (4)Diamond bur, (5)Air-flow and 20 central incisor teeth were used for the control etched group. SBS test were applied on bonded metal brackets to all samples. SBS values and residual adhesives were evaluated. Analysis of variance showed a significant difference (p<0.001) between the groups. Sandblasted group had the highest SBS value (12.85 MPa) in experimental groups. The sandblasting surface treatment is recommended as an effective method of bonding orthodontic metal brackets to nano-hybrid composite resin surfaces.

Magnetron sputtered boron films for increasing hardness of a metal surface

DOEpatents

Makowiecki, Daniel M [Livermore, CA; Jankowski, Alan F [Livermore, CA

2003-05-27

A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for producing hardened surfaces, surfacing machine tools, etc. and for ultra-thin band pass filters as well as the low Z element in low Z/high Z optical components, such as mirrors which enhance reflectivity from grazing to normal incidence.

Synthesis, characterization and adsorption properties of magnetite/reduced graphene oxide nanocomposites.

PubMed

Qi, Tingting; Huang, Chenchen; Yan, Shan; Li, Xiu-Juan; Pan, Si-Yi

2015-11-01

Three kinds of magnetite/reduced graphene oxide (MRGO) nanocomposites were prepared by solvothermal, hydrothermal and co-precipitation methods. The as-prepared nanocomposites were characterized and compared by Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and zeta potential. The results showed that MRGO made by different methods differed in surface functional groups, crystal structure, particle sizes, surface morphology and surface charge. Due to their unlike features, these nanocomposites displayed dissimilar performances when they were used to adsorb drugs, dyes and metal ions. The MRGO prepared by the co-precipitation method showed special adsorption ability to negative ions, but those synthesized by the solvothermal method obtained the best extraction ability and reusability to the others and showed a good prospective in magnetic solid-phase extraction. Therefore, it is highly recommended to use the right preparation method before application in order to attain the best extraction performance. Copyright © 2015 Elsevier B.V. All rights reserved.

Method and apparatus for preparing multiconductor cable with flat conductors

NASA Technical Reports Server (NTRS)

Marcell, G. V. (Inventor)

1969-01-01

A method and apparatus for preparing flat conductor cable having a plurality of ribbon-like conductors disposed upon and adhesively bonded to the surface of a substrate is described. The conductors are brought into contact with the substrate surface, and while maintained in axial tension on said substrate, the combination is seated on a yieldably compressible layer to permit the conductor to become embedded into the surface of the substrate film.

Preparation of surface enhanced Raman substrate and its characterization

NASA Astrophysics Data System (ADS)

Liu, Y.; Wang, J. Y.; Wang, J. Q.

2017-10-01

Surface enhanced Raman spectroscopy (SERS) is a fast, convenient and highly sensitive detection technique, and preparing the good effect and repeatable substrate is the key to realize the trace amount and quantitative detection in the field of food safety detection. In this paper, a surface enhanced Raman substrate based on submicrometer silver particles structure was prepared by chemical deposition method, and characterized its structure and optical properties.

Micro- and nano-porous surface patterns prepared by surface-confined directional melt crystallization of solvent

NASA Astrophysics Data System (ADS)

Kim, Byoung Soo; Kim, Hyun Jin; An, Suyeong; Chi, Sangwon; Kim, Junseok; Lee, Jonghwi

2017-07-01

Recently, numerous attempts have been made to engineer micro- and nano-porous surface patterns or to develop convenient preparation methods for the practical applications of self-cleaning surfaces, water-repellent surfaces, novel textures, etc. Herein, we introduce a simple, cheap, and repeatable crystallization-based method to produce porous surface structures, on any surface of already fabricated polymeric materials. Contact of the solvent phase with cooled polymer surfaces enabled the limited dissolution of the surfaces and the subsequent extremely fast melt crystallization of the solvent. After removing the crystals, various micro- and nano-porous patterns were obtained, whose pore sizes ranged over three orders of magnitude. Pore depth was linearly dependent on the dissolution time. Crystal growth was mainly directed normal to the surfaces, but it was also controlled in-plane, resulting in cylindrical or lamellar structures. Superhydrophobic surfaces were successfully prepared on both polystyrene and polycarbonate. This process offers a novel surface engineering tool for a variety of polymer surfaces, whose topology can be conveniently controlled over a wide range by crystal engineering.

Progress in Preparation of Monodisperse Polymer Microspheres

NASA Astrophysics Data System (ADS)

Zhang, Hongyan

2017-12-01

The monodisperse crosslinked polymer microspheres have attracted much attention because of their superior thermal and solvent resistance, mechanical strength, surface activity and adsorption properties. They are of wide prospects for using in many fields such as biomedicine, electronic science, information technology, analytical chemistry, standard measurement and environment protection etc. Functional polymer microspheres prepared by different methods have the outstanding surface property, quantum size effect and good potential future in applications with its designable structure, controlled size and large ratio of surface to volume. Scholars of all over the world have focused on this hot topic. The preparation method and research progress in functional polymer microspheres are addressed in the paper.

Preparation of nickel oxide thin films at different annealing temperature by sol-gel spin coating method

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

Abdullah, M. A. R., E-mail: ameerridhwan89@gmail.com; Mamat, M. H., E-mail: hafiz-030@yahoo.com; Ismail, A. S., E-mail: kyrin-samaxi@yahoo.com

2016-07-06

Preparation of NiO thin films at different annealing temperature by sol-gel method was conducted to synthesize the quality of the surface thin films. The effects of annealing temperature on the surface topology were systematically investigated. Our studies confirmed that the surface roughness of the thin films was increased whenever annealing temperature was increase. NiO thin films morphology structure analysis was confirmed by field emission scanning electron microscope. Surface roughness of the thin films was investigated by atomic force microscopy.

Analysis and comparison of focused ion beam milling and vibratory polishing sample surface preparation methods for porosity study of U-Mo plate fuel for research and test reactors.

PubMed

Westman, Bjorn; Miller, Brandon; Jue, Jan-Fong; Aitkaliyeva, Assel; Keiser, Dennis; Madden, James; Tucker, Julie D

2018-07-01

Uranium-Molybdenum (U-Mo) low enriched uranium (LEU) fuels are a promising candidate for the replacement of high enriched uranium (HEU) fuels currently in use in a high power research and test reactors around the world. Contemporary U-Mo fuel sample preparation uses focused ion beam (FIB) methods for analysis of fission gas porosity. However, FIB possess several drawbacks, including reduced area of analysis, curtaining effects, and increased FIB operation time and cost. Vibratory polishing is a well understood method for preparing large sample surfaces with very high surface quality. In this research, fission gas porosity image analysis results are compared between samples prepared using vibratory polishing and FIB milling to assess the effectiveness of vibratory polishing for irradiated fuel sample preparation. Scanning electron microscopy (SEM) imaging was performed on sections of irradiated U-Mo fuel plates and the micrographs were analyzed using a fission gas pore identification and measurement script written in MatLab. Results showed that the vibratory polishing method is preferentially removing material around the edges of the pores, causing the pores to become larger and more rounded, leading to overestimation of the fission gas porosity size. Whereas, FIB preparation tends to underestimate due to poor micrograph quality and surface damage leading to inaccurate segmentations. Despite the aforementioned drawbacks, vibratory polishing remains a valid method for porosity analysis sample preparation, however, improvements should be made to reduce the preferential removal of material surrounding pores in order to minimize the error in the porosity measurements. Copyright © 2018 Elsevier Ltd. All rights reserved.

Method for preparing surfaces of metal composites having a brittle phase for plating. [Patent application

DOEpatents

Coates, C.W.; Wilson, T.J.

1982-05-19

The present invention is directed to a method for preparing surfaces of two-phase metal composites having relatively brittle and malleable components for plating with corrosion-resistant material. In practice of the present invention, the surfaces of the composite are etched to remove a major portion or fraction of the brittle component. The etched surface is then peened with particulates for breaking the brittle component from the surfaces and for spreading or smearing the malleable component over the surfaces. The peened surface is then chemically cleaned of residual traces of the brittle component to which the corrosion-resistant material may be plated thereon in an adherent manner.

Method for preparing surfaces of metal composites having a brittle phase for plating

DOEpatents

Coates, Cameron W.; Wilson, Thomas J.

1984-01-01

The present invention is directed to a method for preparing surfaces of two-phase metal composites having relatively brittle and malleable components for plating with corrosion-resistant material. In practice of the present invention, the surfaces of the composites are etched to remove a major portion or fraction of the brittle component. The etched surface is then peened with particulates for breaking the brittle component from the surfaces and for spreading or smearing the malleable component over the surfaces. The peened surface is then chemically cleaned of residual traces of the brittle component so as to provide a surface of essentially the malleable component to which the corrosion-resistant material may be plated thereon in an adherent manner.

Computer-aided design of tooth preparations for automated development of fixed prosthodontics.

PubMed

Yuan, Fusong; Sun, Yuchun; Wang, Yong; Lv, Peijun

2014-01-01

This paper introduces a method to digitally design a virtual model of a tooth preparation of the mandibular first molar, by using the commercial three-dimensional (3D) computer-aided design software packages Geomagic and Imageware, and using the model as an input to automatic tooth preparing system. The procedure included acquisition of 3D data from dentate casts and digital modeling of the shape of the tooth preparation components, such as the margin, occlusal surface, and axial surface. The completed model data were stored as stereolithography (STL) files, which were used in a tooth preparation system to help to plan the trajectory. Meanwhile, the required mathematical models in the design process were introduced. The method was used to make an individualized tooth preparation of the mandibular first molar. The entire process took 15min. Using the method presented, a straightforward 3D shape of a full crown can be obtained to meet clinical needs prior to tooth preparation. © 2013 Published by Elsevier Ltd.

Surface preparation for high purity alumina ceramics enabling direct brazing in hydrogen atmospheres

DOEpatents

Cadden, Charles H.; Yang, Nancy Yuan Chi; Hosking, Floyd M.

2001-01-01

The present invention relates to a method for preparing the surface of a high purity alumina ceramic or sapphire specimen that enables direct brazing in a hydrogen atmosphere using an active braze alloy. The present invention also relates to a method for directly brazing a high purity alumina ceramic or sapphire specimen to a ceramic or metal member using this method of surface preparation, and to articles produced by this brazing method. The presence of silicon, in the form of a SiO.sub.2 -containing surface layer, can more than double the tensile bond strength in alumina ceramic joints brazed in a hydrogen atmosphere using an active Au-16Ni-0.75 Mo-1.75V filler metal. A thin silicon coating applied by PVD processing can, after air firing, produce a semi-continuous coverage of the alumina surface with a SiO.sub.2 film. Room temperature tensile strength was found to be proportional to the fraction of air fired surface covered by silicon-containing films. Similarly, the ratio of substrate fracture versus interface separation was also related to the amount of surface silicon present prior to brazing. This process can replace the need to perform a "moly-manganese" metallization step.

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

Yan, Wei; Liu, Hongtao, E-mail: liuht100@126.com; Sun, Qinghe

A facile and quick fabrication method was proposed to prepare superhydrophobic surfaces on iron substrate by chemical immersion and subsequent stearic acid modification. The association between wettability and surface morphology was studied through altering the copper ion concentration and immersion time. Surface tension instrument, scanning electron microscopy, x-ray diffraction, x-ray photoelectron spectroscopy, and electrochemical workstation were used to characterize the wettability, physical morphology, chemical composition, and corrosion resistance ability of the prepared film. Results showed that both the rough micro/nanostructures and low surface energy material play critical roles in surface wettability. The superhydrophobic film achieved a better anticorrosion property comparedmore » to barrier iron by analysis of open circuit potential, potentiodynamic polarization curves, and Nyquist plots. In addition, the superhydrophobic surface showed excellent performance of acid and alkali resistance, anti-icing, and self-cleaning through a series of environmental tests. This study provides a valid method for quick-preparation of the stable superhydrophobic surfaces, which has a promising application in steel buildings and facilities.« less

Synthesis of nanocrystalline CeO{sub 2} particles by different emulsion methods

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

Supakanapitak, Sunisa; Boonamnuayvitaya, Virote; Jarudilokkul, Somnuk, E-mail: somnuk.jar@kmutt.ac.th

2012-05-15

Cerium oxide nanoparticles were synthesized using three different methods of emulsion: (1) reversed micelle (RM); (2) emulsion liquid membrane (ELM); and (3) colloidal emulsion aphrons (CEAs). Ammonium cerium nitrate and polyoxyethylene-4-lauryl ether (PE4LE) were used as cerium and surfactant sources in this study. The powder was calcined at 500 Degree-Sign C to obtain CeO{sub 2}. The effect of the preparation procedure on the particle size, surface area, and the morphology of the prepared powders were investigated. The obtained powders are highly crystalline, and nearly spherical in shape. The average particle size and the specific surface area of the powders frommore » the three methods were in the range of 4-10 nm and 5.32-145.73 m{sup 2}/g, respectively. The CeO{sub 2} powders synthesized by the CEAs are the smallest average particle size, and the highest surface area. Finally, the CeO{sub 2} prepared by the CEAs using different cerium sources and surfactant types were studied. It was found that the surface tensions of cerium solution and the type of surfactant affect the particle size of CeO{sub 2}. - Graphical Abstract: The emulsion droplet size distribution and the TEM images of CeO{sub 2} prepared by different methods: reversed micelle (RM), emulsion liquid membrane (ELM) and colloidal emulsion aphrons (CEAs). Highlights: Black-Right-Pointing-Pointer Nano-sized CeO{sub 2} was successfully prepared by three different emulsion methods. Black-Right-Pointing-Pointer The colloidal emulsion aphrons method producing CeO{sub 2} with the highest surface area. Black-Right-Pointing-Pointer The surface tensions of a cerium solution have slightly effect on the particle size. Black-Right-Pointing-Pointer The size control could be interpreted in terms of the adsorption of the surfactant.« less

Magnetron sputtered boron films

DOEpatents

Makowiecki, Daniel M.; Jankowski, Alan F.

1998-01-01

A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for producing hardened surfaces, surfacing machine tools, etc. and for ultra-thin band pass filters as well as the low Z element in low Z/high Z optical components, such as mirrors which enhance reflectivity from grazing to normal incidence.

Magnetron sputtered boron films

DOEpatents

Makowiecki, D.M.; Jankowski, A.F.

1998-06-16

A method is described for the production of thin boron and titanium/boron films by magnetron sputter deposition. The amorphous boron films contain no morphological growth features, unlike those found when thin films are prepared by various physical vapor deposition processes. Magnetron sputter deposition method requires the use of a high density crystalline boron sputter target which is prepared by hot isostatic pressing. Thin boron films prepared by this method are useful for producing hardened surfaces, surfacing machine tools, etc. and for ultra-thin band pass filters as well as the low Z element in low Z/high Z optical components, such as mirrors which enhance reflectivity from grazing to normal incidence. 8 figs.

Preparation and Characterization of Nano Gold Supported over Montmorillonite Clays

NASA Astrophysics Data System (ADS)

Suraja, P. V.; Binitha, N. N.; Yaakob, Z.; Silija, P. P.

2011-02-01

The use of montmorillonite clays as a matrix, or as a host, for obtaining intercalated/supported metal particles has potential applications in catalysis and other areas. The gold nanoparticles were obtained from the most common anionic gold precursor HAuCl4·3H2O by deposition-precipitation (DP) methods. However, it is difficult to prepare nanoscale gold catalysts supported on silica surfaces with lower isoelectric point (IEP). Homogeneous precipitation method using urea also fails on silica surfaces. Reasons for the inefficiency of these methods are the negative charge of the metal precursor as well as the support surface and the high pH required for depositing gold nanoparticles. In the present work, we use glucose as the reductant in the presence of stabilizer for preparation of nano gold supported on montmorillonite clay. There is no need of increasing the pH of the solution to reduce the Au3+ ions. The prepared systems are characterized using various techniques such as using X-ray fluorescence (XRF), UV-VIS Diffuse reflectance spectra (DRS) and Fourier Transform infra red spectra (FTIR) to prove the efficiency of the present method.

Ion implantation method for preparing polymers having oxygen erosion resistant surfaces

DOEpatents

Lee, Eal H.; Mansur, Louis K.; Heatherly, Jr., Lee

1995-01-01

Hard surfaced polymers and the method for making them are generally described. Polymers are subjected to simultaneous multiple ion beam bombardment, that results in a hardening of the surface, improved wear resistance, and improved oxygen erosion resistance.

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 surface micro- and nanostructures for superhydrophobic surfaces in electric and electronic applications

NASA Astrophysics Data System (ADS)

Xiu, Yonghao

In our study, the superhydrophobic surface based on biomimetic lotus leave is explored to maintain the desired properties for self-cleaning. Parameters in controlling bead-up and roll-off characteristics of water droplets were investigated on different model surfaces. The governing equations were proposed. Heuristic study is performed. First, the fundamental understanding of the effect of roughness on superhydrophobicity is performed. The effect of hierarchical roughness, i.e., two scale roughness effect on roughness is investigated using systems of (1) monodisperse colloidal silica sphere (submicron) arrays and Au nanoparticle on top and (2) Si micrometer pyramids and Si nanostructures on top from KOH etching and metal assisted etching of Si. The relation between the contact area fraction and water droplet contact angles are derived based on Wenzel and Cassie-Baxter equation for the systems and the two scale effect is explained regarding the synergistic combination of two scales. Previously the microscopic three-phase-contact line is thought to be the key factor in determining contact angles and hystereses. In our study, Laplace pressure was brought up and related to the three-phase-contact line and taken as a key figure of merit in determining superhydrophobicity. In addition, we are one of the first to study the effect of tapered structures (wall inclination). Combining with a second scale roughness on the tapered structures, stable Cassie state for both water and low surface energy oil may be achieved. This is of great significance for designing both superhydrophobicity and superoleophobicity. Regarding the origin of contact angle hysteresis, study of superhydrophobicity on micrometer Si pillars was performed. The relation between the interface work of function and contact angle hysteresis was proposed and derived mathematically based on the Young-Dupre equation. The three-phase-contact line was further related to a secondary scale roughness induced. Based on our understanding of the roughness effect on superhydrophobicity (both contact angle and hysteresis), structured surfaces from polybutadiene, polyurethane, silica, and Si etc. were successfully prepared. For engineering applications of superhydrophobic surfaces, stability issues regarding UV, mechanical robustness and humid environment need to be investigated. Among these factors, UV stability is the first one to be studied. However, most polymer surfaces we prepared failed the purpose. Silica surfaces with excellent UV stability were prepared. This method consists of preparation of rough silica surfaces, thermal treatment and the following surface hydrophobization by fluoroalkyl silane treatment. Fluoroalkyl groups are UV stable and the underlying species are silica which is also UV stable (UV transparent). UV stability on the surface currently is 5,500 h according the standard test method of ASTM D 4329. No degradation on surface superhydrophobicity was observed. New methods for preparing superhydrophobic and transparent silica surfaces were investigated using urea-choline chloride eutectic liquid to generate fine roughness and reduce the cost for preparation of surface structures. Another possible application for self-cleaning in photovoltaic panels was investigated on Si surfaces by construction of the two-scale rough structures followed by fluoroalkyl silane treatment. Metal (Au) assisted etching was employed to fabricate nanostructures on micrometer pyramid surfaces. The light reflection on the prepared surfaces was investigated. After surface texturing using KOH etching for micrometer pyramids and the following nanostructure using metal assisted etching, surface light reflection reduced to a minimum value which shows that this surface texturing technique is highly promising for improving the photovoltaic efficiency while imparting photovoltaics the self-cleaning feature. This surface is also expected to be UV stable due to the same fluoroalkyl silane used. Regarding the mechanical robustness, epoxy-silica superhydrophobic surfaces were prepared by O2 plasma etching to generate enough surface roughness of silica spheres followed by fluoroalkyl silane treatment. A robustness test method was proposed and the test results showed that the surface is among the most robust surfaces for the superhydrophobic surfaces we prepared and currently reported in literature.

Bedrock topography of western Cape Cod, Massachusetts, based on bedrock altitudes from geologic borings and analysis of ambient seismic noise by the horizontal-to-vertical spectral-ratio method

USGS Publications Warehouse

Fairchild, Gillian M.; Lane, John W.; Voytek, Emily B.; LeBlanc, Denis R.

2013-01-01

This report presents a topographic map of the bedrock surface beneath western Cape Cod, Massachusetts, that was prepared for use in groundwater-flow models of the Sagamore lens of the Cape Cod aquifer. The bedrock surface of western Cape Cod had been characterized previously through seismic refraction surveys and borings drilled to bedrock. The borings were mostly on and near the Massachusetts Military Reservation (MMR). The bedrock surface was first mapped by Oldale (1969), and mapping was updated in 2006 by the Air Force Center for Environmental Excellence (AFCEE, 2006). This report updates the bedrock-surface map with new data points collected by using a passive seismic technique based on the horizontal-to-vertical spectral ratio (HVSR) of ambient seismic noise (Lane and others, 2008) and from borings drilled to bedrock since the 2006 map was prepared. The HVSR method is based on a relationship between the resonance frequency of ambient seismic noise as measured at land surface and the thickness of the unconsolidated sediments that overlie consolidated bedrock. The HVSR method was shown by Lane and others (2008) to be an effective method for determining sediment thickness on Cape Cod owing to the distinct difference in the acoustic impedance between the sediments and the underlying bedrock. The HVSR data for 164 sites were combined with data from 559 borings to bedrock in the study area to create a spatially distributed dataset that was manually contoured to prepare a topographic map of the bedrock surface. The interpreted bedrock surface generally slopes downward to the southeast as was shown on the earlier maps by Oldale (1969) and AFCEE (2006). The surface also has complex small-scale topography characteristic of a glacially eroded surface. More information about the methods used to prepare the map is given in the pamphlet that accompanies this plate.

Preparation and High-temperature Anti-adhesion Behavior of a Slippery Surface on Stainless Steel.

PubMed

Zhang, Pengfei; Huawei, Chen; Liu, Guang; Zhang, Liwen; Zhang, Deyuan

2018-03-29

Anti-adhesion surfaces with high-temperature resistance have a wide application potential in electrosurgical instruments, engines, and pipelines. A typical anti-wetting superhydrophobic surface easily fails when exposed to a high-temperature liquid. Recently, Nepenthes-inspired slippery surfaces demonstrated a new way to solve the adhesion problem. A lubricant layer on the slippery surface can act as a barrier between the repelled materials and the surface structure. However, the slippery surfaces in previous studies rarely showed high-temperature resistance. Here, we describe a protocol for the preparation of slippery surfaces with high-temperature resistance. A photolithography-assisted method was used to fabricate pillar structures on stainless steel. By functionalizing the surface with saline, a slippery surface was prepared by adding silicone oil. The prepared slippery surface maintained the anti-wetting property for water, even when the surface was heated to 300 °C. Also, the slippery surface exhibited great anti-adhesion effects on soft tissues at high temperatures. This type of slippery surface on stainless steel has applications in medical devices, mechanical equipment, etc.

Preparation of porous Si and TiO 2 nanofibres using a sulphur-templating method for lithium storage

DOE PAGES

McCormac, Kathleen; Byrd, Ian; Brannen, Rodney; ...

2015-02-03

We prepared highly porous Si/TiO 2 composite nanofibres using a unique sulphur-templating method combined with electrospinning. The structure, morphology, surface area, phase and composition of these nanofibres were characterized using Raman spectroscopy, scanning electron microscopy, powder X-ray diffraction, surface area analyser and thermogravimetric analyser. The specific surface area of Si/TiO 2 porous NFs is as large as 387m 2g -1, whose silicon capacity can be maintained above 1580mAhg -1 in 180 cycles.

Method of preparing size-selected metal clusters

DOEpatents

Elam, Jeffrey W.; Pellin, Michael J.; Stair, Peter C.

2010-05-11

The invention provides a method for depositing catalytic clusters on a surface, the method comprising confining the surface to a controlled atmosphere; contacting the surface with catalyst containing vapor for a first period of time; removing the vapor from the controlled atmosphere; and contacting the surface with a reducing agent for a second period of time so as to produce catalyst-containing nucleation sites.

Method of boronizing transition metal surfaces

DOEpatents

Koyama, Koichiro; Shimotake, Hiroshi

1983-01-01

A method is presented for preparing a boride layer on a transition metal substrate for use in corrosive environments or as a harden surface in machine applications. This method is particularly useful in treating current collectors for use within a high temperature and corrosive electrochemical cell environment. A melt of a alkali metal boride tetrafluoride salt including such as KF to lower its melting point is prepared including a dissolved boron containing material, for instance NiB, MnB.sub.2, or CrB.sub.2. A transition metal to be coated is immersed in the melt at a temperature of no more than 700.degree. C. and a surface boride layer of that transition metal is formed within a period of about 24 hours on the substrate surface.

Ion implantation method for preparing polymers having oxygen erosion resistant surfaces

DOEpatents

Lee, E.H.; Mansur, L.K.; Heatherly, L. Jr.

1995-04-18

Hard surfaced polymers and the method for making them are generally described. Polymers are subjected to simultaneous multiple ion beam bombardment, that results in a hardening of the surface, improved wear resistance, and improved oxygen erosion resistance. 8 figs.

Method of producing nanopatterned articles using surface-reconstructed block copolymer films

DOEpatents

Russell, Thomas P; Park, Soojin; Wang, Jia-Yu; Kim, Bokyung

2013-08-27

Nanopatterned surfaces are prepared by a method that includes forming a block copolymer film on a substrate, annealing and surface reconstructing the block copolymer film to create an array of cylindrical voids, depositing a metal on the surface-reconstructed block copolymer film, and heating the metal-coated block copolymer film to redistribute at least some of the metal into the cylindrical voids. When very thin metal layers and low heating temperatures are used, metal nanodots can be formed. When thicker metal layers and higher heating temperatures are used, the resulting metal structure includes nanoring-shaped voids. The nanopatterned surfaces can be transferred to the underlying substrates via etching, or used to prepare nanodot- or nanoring-decorated substrate surfaces.

Investigations of the fabrication and the surface-enhanced Raman scattering detection applications for tapered fiber probes prepared with the laser-induced chemical deposition method.

PubMed

Fan, Qunfang; Cao, Jie; Liu, Ye; Yao, Bo; Mao, Qinghe

2013-09-01

The process of depositing nanoparticles onto tapered fiber probes with the laser-induced chemical deposition method (LICDM) and the surface-enhanced Raman scattering (SERS) detection performance of the prepared probes are experimentally investigated in this paper. Our results show that the nanoparticle-deposited tapered fiber probes prepared with the LICDM method depend strongly on the value of the cone angle. For small-angle tapered probes the nanoparticle-deposited areas are only focused at the taper tips, because the taper surfaces are mainly covered by a relatively low-intensity evanescent field. By lengthening the reaction time or increasing the induced power or solution concentration, it is still possible to deposit nanoparticles on small-angle tapers with the light-scattering effect. With 4-aminothiophenol as the testing molecule, it was found that for given preparation conditions, the cone angles for the tapered probes with the highest SERS spectral intensities for different excitation laser powers are almost the same. However, such an optimal cone angle is determined by the combined effects of both the localized surface plasmon resonance strength and the transmission loss generated by the nanoparticles deposited.

Preparation of clean surfaces and Se vacancy formation in Bi2Se3 by ion bombardment and annealing

NASA Astrophysics Data System (ADS)

Zhou, Weimin; Zhu, Haoshan; Valles, Connie M.; Yarmoff, Jory A.

2017-08-01

Bismuth Selenide (Bi2Se3) is a topological insulator (TI) with a structure consisting of stacked quintuple layers. Single crystal surfaces are commonly prepared by mechanical cleaving. This work explores the use of low energy Ar+ ion bombardment and annealing (IBA) as an alternative method to produce reproducible and stable Bi2Se3 surfaces under ultra-high vacuum (UHV). It is found that a clean and well-ordered surface can be prepared by a single cycle of 1 keV Ar+ ion bombardment and 30 min of annealing. Low energy electron diffraction (LEED) and detailed low energy ion scattering (LEIS) measurements show no differences between IBA-prepared surfaces and those prepared by in situ cleaving in UHV. Analysis of the LEED patterns shows that the optimal annealing temperature is 450 °C. Angular LEIS scans reveal the formation of surface Se vacancies when the annealing temperature exceeds 520 °C.

Products of n-hexane oxidation with air oxygen on an activated carbon surface

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

Barkauskas, Yu.; Kareiva, A.

Products of n-hexane oxidation on an activated carbon surface have been investigated. Carbon samples have been prepared using the Plackett-Burman method of mathematical design. The influence of carbon preparation stages on the composition of products of n-hexane oxidation has been discussed.

Process for the preparation of organoclays

DOEpatents

Chaiko, David J.

2004-11-23

A method for preparing organoclays for use as rheological control agents and in the preparation of nanocomposites. Typically, the clay is dispersed in water, and a specific amount of polymeric hydrotrope, ranging from 0.1 to 15 weight percent relative to the weight of the clay, is adsorbed onto the clay surface. Quaternary amine exchange is also performed on the clay to modify the surface hydrophilic/lipophilic balance (HLB) of the clay.

Process for the preparation of organoclays

DOEpatents

Chaiko, David J.

2003-01-01

A method for preparing organoclays from smectites for use as rheological control agents and in the preparation of nanocomposites. Typically, the clay is dispersed in water, and a substantially monomolecular layer of a water soluble polymer is applied to the surfaces of the clay. A surfactant is also applied to the clay to modify the surface hydrophilic/hydrophobic balance of the clay, and the organoclay is separated out for subsequent use.

A Rapid One-Step Process for Fabrication of Biomimetic Superhydrophobic Surfaces by Pulse Electrodeposition.

PubMed

Jiang, Shuzhen; Guo, Zhongning; Liu, Guixian; Gyimah, Glenn Kwabena; Li, Xiaoying; Dong, Hanshan

2017-10-25

Inspired by some typical plants such as lotus leaves, superhydrophobic surfaces are commonly prepared by a combination of low surface energy materials and hierarchical micro/nano structures. In this work, superhydrophobic surfaces on copper substrates were prepared by a rapid, facile one-step pulse electrodepositing process, with different duty ratios in an electrolyte containing lanthanum chloride (LaCl₃·6H₂O), myristic acid (CH₃(CH₂) 12 COOH), and ethanol. The equivalent electrolytic time was only 10 min. The surface morphology, chemical composition and superhydrophobic property of the pulse electrodeposited surfaces were fully investigated with SEM, EDX, XRD, contact angle meter and time-lapse photographs of water droplets bouncing method. The results show that the as-prepared surfaces have micro/nano dual scale structures mainly consisting of La[CH₃(CH₂) 12 COO]₃ crystals. The maximum water contact angle (WCA) is about 160.9°, and the corresponding sliding angle is about 5°. This method is time-saving and can be easily extended to other conductive materials, having a great potential for future applications.

A Rapid One-Step Process for Fabrication of Biomimetic Superhydrophobic Surfaces by Pulse Electrodeposition

PubMed Central

Jiang, Shuzhen; Guo, Zhongning; Liu, Guixian; Gyimah, Glenn Kwabena; Li, Xiaoying; Dong, Hanshan

2017-01-01

Inspired by some typical plants such as lotus leaves, superhydrophobic surfaces are commonly prepared by a combination of low surface energy materials and hierarchical micro/nano structures. In this work, superhydrophobic surfaces on copper substrates were prepared by a rapid, facile one-step pulse electrodepositing process, with different duty ratios in an electrolyte containing lanthanum chloride (LaCl3·6H2O), myristic acid (CH3(CH2)12COOH), and ethanol. The equivalent electrolytic time was only 10 min. The surface morphology, chemical composition and superhydrophobic property of the pulse electrodeposited surfaces were fully investigated with SEM, EDX, XRD, contact angle meter and time-lapse photographs of water droplets bouncing method. The results show that the as-prepared surfaces have micro/nano dual scale structures mainly consisting of La[CH3(CH2)12COO]3 crystals. The maximum water contact angle (WCA) is about 160.9°, and the corresponding sliding angle is about 5°. This method is time-saving and can be easily extended to other conductive materials, having a great potential for future applications. PMID:29068427

Effect of surface preparation with Nd:YAG and Er,Cr:YSGG lasers on the repair bond strength of lithium disilicate glass ceramic to a silorane-based composite resin.

PubMed

Ebrahimi Chaharom, Mohammad Esmaeel; Pournaghi Azar, Fatemeh; Mohammadi, Narmin; Nasiri, Rezvan

2018-01-01

Background. This study was undertaken to evaluate the repair bond strength of lithium disilicate glass ceramic to a silorane-based composite resin after surface preparation with Nd:YAG and Er,Cr:YSGG lasers. Methods. A total of 102 lithium disilicate glass ceramic samples (IPS e.max Press), measuring 5 mm in diameter and 4 mm in thickness, were randomly assigned to 6 groups (n=17): group 1, no surface preparation (control); group 2, acid etching with 9.5% hydrofluoric acid (HF); group 3, surface preparation with 4.5-W Nd:YAG laser; group 4, surface preparation with 6-W Nd:YAG laser; group 5, surface preparation with 1.5-W Er,Cr:YSGG laser; and group 6, surface preparation with 6-W Er,Cr:YSGG laser. After preparation of surfaces and application of silane, all the samples were repaired with the use of a silorane-based composite resin, followed by storage in distilled water at a temperature of 37°C for 24 hours and thermocycling. Finally, the samples were subjected to a shearing bond strength test; the fracture modes were determined under a stereomi-croscope. Results. There were significant differences between the HF group and the other groups (P=0.000). Two-by-two comparisons of the other groups revealed no significant differences (P>0.05). Conclusion. Use of HF proved the most effective surface preparation technique to increase the repair bond strength between lithium disilicate glass ceramic and silorane-based composite resin; compared to the control group.

Method of boronizing transition metal surfaces

DOEpatents

Koyama, Koichiro; Shimotake, Hiroshi.

1983-08-16

A method is presented for preparing a boride layer on a transition metal substrate for use in corrosive environments or as a harden surface in machine applications. This method is particularly useful in treating current collectors for use within a high temperature and corrosive electrochemical cell environment. A melt of a alkali metal boride tetrafluoride salt including such as KF to lower its melting point is prepared including a dissolved boron containing material, for instance NiB, MnB[sub 2], or CrB[sub 2]. A transition metal to be coated is immersed in the melt at a temperature of no more than 700 C and a surface boride layer of that transition metal is formed within a period of about 24 hours on the substrate surface. 4 figs.

Epitaxial growth of silicon for layer transfer

DOEpatents

Teplin, Charles; Branz, Howard M

2015-03-24

Methods of preparing a thin crystalline silicon film for transfer and devices utilizing a transferred crystalline silicon film are disclosed. The methods include preparing a silicon growth substrate which has an interface defining substance associated with an exterior surface. The methods further include depositing an epitaxial layer of silicon on the silicon growth substrate at the surface and separating the epitaxial layer from the substrate substantially along the plane or other surface defined by the interface defining substance. The epitaxial layer may be utilized as a thin film of crystalline silicon in any type of semiconductor device which requires a crystalline silicon layer. In use, the epitaxial transfer layer may be associated with a secondary substrate.

Lattice matched semiconductor growth on crystalline metallic substrates

DOEpatents

Norman, Andrew G; Ptak, Aaron J; McMahon, William E

2013-11-05

Methods of fabricating a semiconductor layer or device and said devices are disclosed. The methods include but are not limited to providing a metal or metal alloy substrate having a crystalline surface with a known lattice parameter (a). The methods further include growing a crystalline semiconductor alloy layer on the crystalline substrate surface by coincident site lattice matched epitaxy. The semiconductor layer may be grown without any buffer layer between the alloy and the crystalline surface of the substrate. The semiconductor alloy may be prepared to have a lattice parameter (a') that is related to the lattice parameter (a). The semiconductor alloy may further be prepared to have a selected band gap.

Surface preparation effects on GTA (gas tungsten arc) weld penetration in JBK-75 stainless steel

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

Campbell, R.D.; Heiple, C.R.; Sturgill, P.L.

1989-01-01

The results of a study are reported here on the effects of surface preparation on the shape of GTA welds on JBK-75, an austenitic precipitation hardenable stainless steel similar to A286. Minor changes in surface (weld groove) preparation produced substantial changes in the penetration characteristics and welding behavior of this alloy. Increased and more consistent weld penetration (higher d/w ratios) along with improved arc stability and less arc wander result from wire brushing and other abrasive surface preparations, although chemical and machining methods did not produce any improvement in penetration. Abrasive treatments roughen the surface, increase the surface area, andmore » increase the surface oxide thickness. The increased weld d/w ratio is attributed to oxygen added to the weld pool from the surface oxide on the base metal. The added oxygen alters the surface-tension driven fluid flow pattern in the weld pool. Similar results were observed with changes in filler wire surface oxide thickness, caused by changes in wire production conditions. 15 refs., 14 figs., 4 tabs.« less

Method for preparation of thermally and mechanically stable metal/porous substrate composite membranes

DOEpatents

Damle, Ashok S.

2004-07-13

A method is provided for the preparation of metal/porous substrate composite membranes by flowing a solution of metal to be plated over a first surface of a porous substrate and concurrently applying a pressure of gas on a second surface of the porous substrate, such that the porous substrate separates the solution of metal from the gas, and the use of the resulting membrane for the production of highly purified hydrogen gas.

Preparation of 1,3,5-triamo-2,4,6-trinitrobenzene of submicron particle size

DOEpatents

Rigdon, Lester P [Livermore, CA; Moody, Gordon L [Tracy, CA; McGuire, Raymond R [Brentwood, CA

2001-05-01

A method is disclosed for the preparation of very small particle size, relatively pure 1,3,5-triamino-2,4,6-trinitrobenzene (TATB). Particles of TATB prepared according to the disclosed method are of submicron size and have a surface area in the range from about 3.8 to 27 square meters per gram.

Preparation of 1,3,5-triamino-2,4,6-trinitrobenzene of submicron particle size

DOEpatents

Rigdon, Lester P.; Moody, Gordon L.; McGuire, Raymond R.

2001-01-01

A method is disclosed for the preparation of very small particle size, relatively pure 1,3,5-triamino-2,4,6-trinitrobenzene (TATB). Particles of TATB prepared according to the disclosed method are of submicron size and have a surface area in the range from about 3.8 to 27 square meters per gram.

Adhesive bonded structural repair. II - Surface preparation procedures, tools, equipment and facilities

NASA Astrophysics Data System (ADS)

Wegman, Raymond F.; Tullos, Thomas R.

1993-10-01

A development status report is presented on the surface preparation procedures, tools, equipment, and facilities used in adhesively-bonded repair of aerospace and similar high-performance structures. These methods extend to both metallic and polymeric surfaces. Attention is given to the phos-anodize containment system, paint removal processes, tools for cutting composite prepreg and fabric materials, autoclaves, curing ovens, vacuum bagging, and controlled atmospheres.

CMC-modified cellulose biointerface for antibody conjugation.

PubMed

Orelma, Hannes; Teerinen, Tuija; Johansson, Leena-Sisko; Holappa, Susanna; Laine, Janne

2012-04-09

In this Article, we present a new strategy for preparing an antihemoglobin biointerface on cellulose. The preparation method is based on functionalization of the cellulose surface by the irreversible adsorption of CMC, followed by covalent linking of antibodies to CMC. This would provide the means for affordable and stable cellulose-based biointerfaces for immunoassays. The preparation and characterization of the biointerface were studied on Langmuir-Schaefer cellulose model surfaces in real time using the quartz crystal microbalance with dissipation and surface plasmon resonance techniques. The stable attachment of antihemoglobin to adsorbed CMC was achieved, and a linear calibration of hemoglobin was obtained. CMC modification was also observed to prevent nonspecific protein adsorption. The antihemoglobin-CMC surface regenerated well, enabling repeated immunodetection cycles of hemoglobin on the same surface.

The Preparation, Characterization, Mechanical and Antibacterial Properties of GO-ZnO Nanocomposites with a Poly(l-lactide)-Modified Surface

PubMed Central

Yuan, Mingwei; Xiong, Chengdong; Jiang, Lin; Li, Hongli

2018-01-01

Graphene oxide (GO) was employed for the preparation of GO-zinc oxide (ZnO). The hydroxyl group on the surface was exploited to trigger the l-lactide ring-opening polymerization. A composite material with poly(l-lactide) (PLLA) chains grafted to the GO-ZnO surface, GO-ZnO-PLLA, was prepared. The results demonstrated that the employed method allowed one-step, rapid grafting of PLLA to the GO-ZnO surface. The chemical structure of the GO surface was altered by improved dispersion of GO-ZnO in organic solvents, thus enhancing the GO-ZnO dispersion in the PLLA matrix and the interface bonding with PLLA. Subsequently, composite films, GO-ZnO-PLLA and GO-ZnO-PLLA/PLLA, were prepared. The changes in interface properties and mechanical properties were studied. Furthermore, the antibacterial performance of nano-ZnO was investigated. PMID:29473891

Magnetoelectrets prepared by using temperature gradient method

NASA Astrophysics Data System (ADS)

Ojha, Pragya; Qureshi, M. S.; Malik, M. M.

2015-05-01

A novel Temperature Gradient method for preparation of magnetoelectret is proposed. Non uniform magnetic field and temperature gradient are expected to be the main cause for the formation of magnetoelectrets (MEs). Being bad conductors of heat, during their formation, there is a possibility for the existence of a temperature gradient along the dielectric electrode interface. In this condition, the motion of, molecules and charge carriers are dependent on Temperature Gradient in a preferred direction. To increase this temperature gradient on both sides of the sample novel method for the preparation of MEs is developed for the first time. For this method the special sample holders are designed in our laboratory. MEs are prepared in such a way that one surface is cooled and the other is heated, during the process. With the help of XRD analysis using Type-E orientation pattern and surface charge studies on magnetoelectrets, the two main causes Non uniform magnetic field and temperature gradient for the formation of magnetoelectrets (MEs), are authenticated experimentally.

Method of high-density foil fabrication

DOEpatents

Blue, Craig A.; Sikka, Vinod K.; Ohriner, Evan K.

2003-12-16

A method for preparing flat foils having a high density includes the steps of mixing a powdered material with a binder to form a green sheet. The green sheet is exposed to a high intensity radiative source adapted to emit radiation of wavelengths corresponding to an absorption spectrum of the powdered material. The surface of the green sheet is heated while a lower sub-surface temperature is maintained. An apparatus for preparing a foil from a green sheet using a radiation source is also disclosed.

A simple way to achieve bioinspired hybrid wettability surface with micro/nanopatterns for efficient fog collection.

PubMed

Yin, Kai; Du, Haifeng; Dong, Xinran; Wang, Cong; Duan, Ji-An; He, Jun

2017-10-05

Fog collection is receiving increasing attention for providing water in semi-arid deserts and inland areas. Inspired by the fog harvesting ability of the hydrophobic-hydrophilic surface of Namib desert beetles, we present a simple, low-cost method to prepare a hybrid superhydrophobic-hydrophilic surface. The surface contains micro/nanopatterns, and is prepared by incorporating femtosecond-laser fabricated polytetrafluoroethylene nanoparticles deposited on superhydrophobic copper mesh with a pristine hydrophilic copper sheet. The as-prepared surface exhibits enhanced fog collection efficiency compared with uniform (super)hydrophobic or (super)hydrophilic surfaces. This enhancement can be tuned by controlling the mesh number, inclination angle, and fabrication structure. Moreover, the surface shows excellent anti-corrosion ability after immersing in 1 M HCl, 1 M NaOH, and 10 wt% NaCl solutions for 2 hours. This work may provide insight into fabricating hybrid superhydrophobic-hydrophilic surfaces for efficient atmospheric water collection.

CTEPP STANDARD OPERATING PROCEDURE FOR EXTRACTING AND PREPARING DERMAL WIPE AND SURFACE WIPE SAMPLES FOR ANALYSIS OF POLAR ORGANIC POLLUTANTS (SOP-5.27)

EPA Science Inventory

The method for extracting and preparing a dermal or surface wipe sample for analysis of acidic persistent organic pollutants is summarized in this standard operating procedure. It covers the extraction and concentration of samples that are to be analyzed by gas chromatography/mas...

Producing desired ice faces

PubMed Central

Shultz, Mary Jane; Brumberg, Alexandra; Bisson, Patrick J.; Shultz, Ryan

2015-01-01

The ability to prepare single-crystal faces has become central to developing and testing models for chemistry at interfaces, spectacularly demonstrated by heterogeneous catalysis and nanoscience. This ability has been hampered for hexagonal ice, Ih––a fundamental hydrogen-bonded surface––due to two characteristics of ice: ice does not readily cleave along a crystal lattice plane and properties of ice grown on a substrate can differ significantly from those of neat ice. This work describes laboratory-based methods both to determine the Ih crystal lattice orientation relative to a surface and to use that orientation to prepare any desired face. The work builds on previous results attaining nearly 100% yield of high-quality, single-crystal boules. With these methods, researchers can prepare authentic, single-crystal ice surfaces for numerous studies including uptake measurements, surface reactivity, and catalytic activity of this ubiquitous, fundamental solid. PMID:26512102

Novel surface modification of polymer-based separation media controlling separation selectivity, retentivity and generation of electroosmotic flow.

PubMed

Hosoya, Ken; Kubo, Takuya; Takahashi, Katsuo; Ikegami, Tohru; Tanaka, Nobuo

2002-12-06

Uniformly sized packing materials based on synthetic polymer particles for high-performance liquid chromatography (HPLC) and capillary electrochromatography (CEC) have been prepared from polymerization mixtures containing methacrylic acid (MAA) as a functional monomer and by using a novel surface modification method. This "dispersion method" affords effectively modified separation media. Both the amount of MAA utilized in the preparation and reaction time affect the selectivity of chromatographic separation in both the HPLC and the CEC mode and electroosmotic flow. This detailed study revealed that the dispersion method effectively modified internal surface of macroporous separation media and, based on the amount of MAA introduced, exclusion mechanism for the separation of certain solutes could be observed.

Method and device for producing and delivering an aerosol for remote sealing and coating

DOEpatents

Modera, M.P.; Carrie, F.R.

1996-06-04

The invention is a method and device for sealing leaks remotely by means of injecting a previously prepared aerosol into the enclosure being sealed. Specifically the invention is a method and device for preparing, transporting, and depositing and solid phase aerosol to the interior surface of the enclosure. 1 fig.

Adsorption and wetting characterization of hydrophobic SBA-15 silicas.

PubMed

Bernardoni, Frank; Fadeev, Alexander Y

2011-04-15

This work describes adsorption and wetting characterization of hydrophobic ordered mesoporous silicas (OMSs) with the SBA-15 motif. Three synthetic approaches to prepare hydrophobic SBA-15 silicas were explored: grafting with (1) covalently-attached monolayers (CAMs) of C(n)H(2)(n+1)Si(CH(3))(2)N(CH(3))(2), (2) self-assembled monolayers (SAMs) of C(n)H(2)(n+1)Si(OEt)(3), and (3) direct ("one-pot") co-condensation of TEOS with C(n)H(2)(n+1)Si(OEt)(3) in presence of P123 (n=1-18). The materials prepared were characterized by nitrogen adsorption, TEM, and chemical analysis. The surface properties of the materials were assessed by water contact angles (CAs) and by BET C constants. The results showed that, while loadings of the alkyl groups (%C) were comparable, the surface properties and pore ordering of the materials prepared through different methods were quite different. The best quality hydrophobic surfaces were prepared for SBA-15 grafted with CAMs of alkylsilanes. For these materials, the water CAs were above ∼120°/100° (adv/rec) and BET C constants were in the range of ∼15-25, indicating uniform low-energy surfaces of closely packed alkyl groups on external and internal surfaces of the pores respectively. Moreover, surfaces grafted with the long-chained (C(12)-C(18)) silanes showed super-hydrophobic behavior (CAs∼150-180°) and extremely low adhesion for water. The pore uniformity of parental SBA-15 was largely preserved and the pore volume and pore diameter were consistent with the formation of a single layer of alkylsilyl groups inside the pores. Post-synthesis grafting of SBA-15 with SAMs worked not as well as CAMs: the surfaces prepared demonstrated lower water CAs and higher BET C constants, thereby indicating a small amount of accessible polar groups (Si-OH) related to packing constrains for SAMs supported on highly curved surfaces of mesopores. The co-condensation method produced substantially more disordered materials and less hydrophobic surfaces than any of the grafting methods. The surfaces of these materials showed low water CAs and high BET C constants (∼100-200) thereby demonstrating a non-uniform surface coverage and presence of unmodified silica. It is concluded that CAMs chemistry is the most efficient approach in preparation of the functionalized OMS materials with uniform surfaces and pores. Copyright © 2011 Elsevier Inc. All rights reserved.

Precise micropatterning of silver nanoparticles on plastic substrates

NASA Astrophysics Data System (ADS)

Ammosova, Lena; Jiang, Yu; Suvanto, Mika; Pakkanen, Tapani A.

2017-04-01

Conventional fabrication methods to obtain metal patterns on polymer substrates are restricted by high operating temperature and complex preparation steps. The present study demonstrates a simple yet versatile method for preparation of silver nanoparticle micropatterns on polymer substrates with various surface geometry. With the microworking robot technique, we were able not only to directly structure the surface, but also precisely deposit silver nanoparticle ink on the desired surface location with the minimum usage of ink material. The prepared silver nanoparticle ink, containing silver cations and polyethylene glycol (PEG) as a reducing agent, yields silver nanoparticle micropatterns on plastic substrates at low sintering temperature without any contamination. The influence of the ink behaviour was studied, such as substrate wettability, ink volume, and sintering temperature. The ultraviolet visible (UV-vis), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) measurements revealed the formation of micropatterns with uniformly distributed silver nanoparticles. The prepared patterns are expected to have a broad range of applications in optics, medicine, and sensor devices owing to the unique properties of silver. Furthermore, the deposition of a chemical compound, which is different from the substrate material, not only adds a fourth dimension to the prestructured three-dimensional (3D) surfaces, but also opens new application areas to the conventional surface structures.

Comparison of Three Methods for Generating Superhydrophobic, Superoleophobic Nylon Nonwoven Surfaces (Postprint)

DTIC Science & Technology

2011-04-01

AFRL-RX-TY-TP-2010-0076 COMPARISON OF THREE METHODS FOR GENERATING SUPERHYDROPHOBIC , SUPEROLEOPHOBIC NYLON NONWOVEN SURFACES Rahul Saraf...Generating Superhydrophobic , Superoleophobic Nylon Nonwoven Surfaces (POSTPRINT) FA8650-07-1-5916 0602102F GOVT L0 QL102006 ^Saraf, Rahul,; ^Lee, Hoon...Document contains color images. This research deals with creating a superhydrophobic /superoleophobic surface by preparing a metastable Cassie

Effect of bath temperature on surface morphology and photocatalytic activity of ZnO nanorods

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

Sriharan, N.; Senthil, T. S., E-mail: tssenthi@gmail.com; Muthukumarasamy, N.

2016-05-06

ZnO nanorods were prepared by using simple hydrothermal method using four different bath temperatures. All the prepared ZnO nanorods are annealed at 450°C and are characterized by using various techniques such as X-ray diffraction, UV spectra and scanning electron microscopy. Photocatalytic activity of the prepared ZnO nanorods is analyzed. A novel photocatalytic reactor designed with ZnO nanorods prepared at 90°C shows enhanced catalytic efficiency. The role of light irradiation time, bath temperature and surface morphology of the ZnO nanorods on the performance of photocatalytic reaction is analyzed.

Bioactivity of CaSiO3/poly-lactic acid (PLA) composites prepared by various surface loading methods of CaSiO3 powder.

PubMed

Okada, Kiyoshi; Hasegawa, Fumikazu; Kameshima, Yoshikazu; Nakajima, Akira

2007-05-01

Mixing bioactive ceramic powders with polymers is an effective method for generating bioactivity to the polymer-matrix composites but it is necessary to incorporate up to 40 vol% of bioactive ceramic powder. However, such a high mixing ratio offsets the advantages of the flexibility and formability of polymer matrix and it would be highly advantageous to lower the mixing ratio. Since surface loading of ceramic powders in the polymer is thought to be an effective way of reducing the mixing ratio of the ceramic powder while maintaining bioactive activity, CaSiO(3)/poly-lactic acid (PLA) composites were prepared by three methods; (1) casting, (2) spin coating and (3) hot pressing. In methods (1) and (2), a suspension was prepared by dissolving PLA in chloroform and dispersing CaSiO(3) powder in it. The suspension was cast and dried to form a film in the case of method (1) while it was spin-coated on a PLA substrate in method (2). In method (3), CaSiO(3) powder was surface loaded on to a PLA substrate by hot pressing. The bioactivity of these samples was investigated in vitro using simulated body fluid (SBF). Apatite formation was not observed in the samples prepared by method (1) but some apatite formation was achieved by mixing polyethylene glycol (PEG) with the PLA, producing a porous polymer matrix. In method (2), apatite was clearly observed after soaking for 7 days. Enhanced apatite formation was observed in method (3), the thickness of the resulting apatite layers becoming about 20 microm after soaking for 14 days. Since the amount of CaSiO(3) powder used in these samples was only

Bioactivity of CaSiO3/poly-lactic acid (PLA) composites prepared by various surface loading methods of CaSiO3 powder.

PubMed

Okada, Kiyoshi; Hasegawa, Fumikazu; Kameshima, Yoshikazu; Nakajima, Akira

2007-08-01

Mixing bioactive ceramic powders with polymers is an effective method for generating bioactivity to the polymer-matrix composites but it is necessary to incorporate up to 40 vol% of bioactive ceramic powder. However, such a high mixing ratio offsets the advantages of the flexibility and formability of polymer matrix and it would be highly advantageous to lower the mixing ratio. Since surface loading of ceramic powders in the polymer is thought to be an effective way of reducing the mixing ratio of the ceramic powder while maintaining bioactive activity, CaSiO(3)/poly-lactic acid (PLA) composites were prepared by three methods; (1) casting, (2) spin coating and (3) hot pressing. In methods (1) and (2), a suspension was prepared by dissolving PLA in chloroform and dispersing CaSiO(3) powder in it. The suspension was cast and dried to form a film in the case of method (1) while it was spin-coated on a PLA substrate in method (2). In method (3), CaSiO(3) powder was surface loaded on to a PLA substrate by hot-pressing. The bioactivity of these samples was investigated in vitro using simulated body fluid (SBF). Apatite formation was not observed in the samples prepared by method (1) but some apatite formation was achieved by mixing polyethylene glycol (PEG) with the PLA, producing a porous polymer matrix. In method (2), apatite was clearly observed after soaking for 7 days. Enhanced apatite formation was observed in method (3), the thickness of the resulting apatite layers becoming about 20 microm after soaking for 14 days. Since the amount of CaSiO(3) powder used in these samples was only < or =0.4 vol%, it is concluded that this preparation method is very effective in generating bioactivity in polymer-matrix composites by loading with only very small amounts of ceramic powder.

Effect of different catalyst preparation methods on the synthesis of carbon nanotubes with the flame pyrolysis method

NASA Astrophysics Data System (ADS)

Guo, Yonghong; Zhai, Gang; Ru, Yu; Wu, Chuyu; Jia, Xiaowei; Sun, Yaping; Yu, Jiawen; Kang, Zhizhong; Sun, Baomin

2018-03-01

The Flame pyrolysis method used to synthesize carbon nanotubes was studied in this work. In order to improve the quality of synthesized carbon nanotubes, it is important to change the corresponding natures of the catalyst. Two catalyst preparation methods, namely, the sol-gel method and the impregnation method, were compared in this experiment. The properties of the catalyst are analyzed in depth by energy dispersive spectrometer (EDS), x-ray diffraction (XRD), temperature program reduction (TPR). The generation of carbon nanotubes was systematically analysed through scanning electron microscope (SEM), molecule dynamics (MD), raman spectroscopy and transmission electron microscope (TEM). The results show that the catalysts prepared by the impregnation method are stickier, dispersed and easier to dip onto the probe or substrate, which is beneficial for the large-scale production of carbon tubes. The specific surface area of alumina is larger and the iron and molybdenum oxide are more evenly dispersed on the surface of alumina. The carbon nanotubes produced by the catalysts prepared by impregnation method are flatter and have less impurities. The ratio of ID/IG+ is 29.7% lower than that of the sol-gel method in the Raman spectra. The TEM statistics show that the average diameter of the carbon tubes decreases by 23.3%. Therefore, the impregnation method can improve the quality of carbon nanotubes in the case of a similar degree of difficulty in the preparation of the catalyst.

Preparation of anti-adhesion surfaces on aluminium substrates of rubber plastic moulds using a coupling method of liquid plasma and electrochemical machining

NASA Astrophysics Data System (ADS)

Meng, Jianbing; Dong, Xiaojuan; Wei, Xiuting; Yin, Zhanmin

2014-03-01

Hard anti-adhesion surfaces, with low roughness and wear resistance, on aluminium substrates of rubber plastic moulds were fabricated via a new coupling method of liquid plasma and electrochemical machining. With the aid of liquid plasma thermal polishing and electrochemical anodic dissolution, micro/nano-scale binary structures were prepared as the base of the anti-adhesion surfaces. The anti-adhesion behaviours of the resulting aluminium surfaces were analysed by a surface roughness measuring instrument, a scanning electron microscope (SEM), a Fourier-transform infrared spectrophotometer (FTIR), an X-ray diffractometer (XRD), an optical contact angle meter, a digital Vickers micro-hardness (Hv) tester, and electronic universal testing. The results show that, after the liquid plasma and electrochemical machining, micro/nano-scale binary structures composed of micro-scale pits and nano-scale elongated boss structures were present on the sample surfaces. As a result, the anti-adhesion surfaces fabricated by the above coupling method have good anti-adhesion properties, better wear resistance and lower roughness.

Preparation of anti-adhesion surfaces on aluminium substrates of rubber plastic moulds using a coupling method of liquid plasma and electrochemical machining

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

Meng, Jianbing, E-mail: jianbingmeng@126.com; Dong, Xiaojuan; Wei, Xiuting

Hard anti-adhesion surfaces, with low roughness and wear resistance, on aluminium substrates of rubber plastic moulds were fabricated via a new coupling method of liquid plasma and electrochemical machining. With the aid of liquid plasma thermal polishing and electrochemical anodic dissolution, micro/nano-scale binary structures were prepared as the base of the anti-adhesion surfaces. The anti-adhesion behaviours of the resulting aluminium surfaces were analysed by a surface roughness measuring instrument, a scanning electron microscope (SEM), a Fourier-transform infrared spectrophotometer (FTIR), an X-ray diffractometer (XRD), an optical contact angle meter, a digital Vickers micro-hardness (Hv) tester, and electronic universal testing. The resultsmore » show that, after the liquid plasma and electrochemical machining, micro/nano-scale binary structures composed of micro-scale pits and nano-scale elongated boss structures were present on the sample surfaces. As a result, the anti-adhesion surfaces fabricated by the above coupling method have good anti-adhesion properties, better wear resistance and lower roughness.« less

In Situ Preparation of Biomimetic Thin Films and Their Surface-Shielding Effect for Organisms in High Vacuum

PubMed Central

Muranaka, Yoshinori; Shimomura, Masatsugu; Hariyama, Takahiko

2013-01-01

Self-standing biocompatible films have yet to be prepared by physical or chemical vapor deposition assisted by plasma polymerization because gaseous monomers have thus far been used to create only polymer membranes. Using a nongaseous monomer, we previously found a simple fabrication method for a free-standing thin film prepared from solution by plasma polymerization, and a nano-suit made by polyoxyethylene (20) sorbitan monolaurate can render multicellular organisms highly tolerant to high vacuum. Here we report thin films prepared by plasma polymerization from various monomer solutions. The films had a flat surface at the irradiated site and were similar to films produced by vapor deposition of gaseous monomers. However, they also exhibited unique characteristics, such as a pinhole-free surface, transparency, solvent stability, flexibility, and a unique out-of-plane molecular density gradient from the irradiated to the unirradiated surface of the film. Additionally, covering mosquito larvae with the films protected the shape of the organism and kept them alive under the high vacuum conditions in a field emission-scanning electron microscope. Our method will be useful for numerous applications, particularly in the biological sciences. PMID:24236023

Silver Vanadium Phosphorous Oxide, Ag(2)VO(2)PO(4): Chimie Douce Preparation and Resulting Lithium Cell Electrochemistry.

PubMed

Kim, Young Jin; Marschilok, Amy C; Takeuchi, Kenneth J; Takeuchi, Esther S

2011-08-15

Recently, we have shown silver vanadium phosphorous oxide (Ag(2)VO(2)PO(4), SVPO) to be a promising cathode material for lithium based batteries. Whereas the first reported preparation of SVPO employed an elevated pressure, hydrothermal approach, we report herein a novel ambient pressure synthesis method to prepare SVPO, where our chimie douce preparation is readily scalable and provides material with a smaller, more consistent particle size and higher surface area relative to SVPO prepared via the hydrothermal method. Lithium electrochemical cells utilizing SVPO cathodes made by our new process show improved power capability under constant current and pulse conditions over cells containing cathode from SVPO prepared via the hydrothermal method.

Gold cleaning methods for preparation of cell culture surfaces for self-assembled monolayers of zwitterionic oligopeptides.

PubMed

Enomoto, Junko; Kageyama, Tatsuto; Myasnikova, Dina; Onishi, Kisaki; Kobayashi, Yuka; Taruno, Yoko; Kanai, Takahiro; Fukuda, Junji

2018-05-01

Self-assembled monolayers (SAMs) have been used to elucidate interactions between cells and material surface chemistry. Gold surfaces modified with oligopeptide SAMs exhibit several unique characteristics, such as cell-repulsive surfaces, micropatterns of cell adhesion and non-adhesion regions for control over cell microenvironments, and dynamic release of cells upon external stimuli under culture conditions. However, basic procedures for the preparation of oligopeptide SAMs, including appropriate cleaning methods of the gold surface before modification, have not been fully established. Because gold surfaces are readily contaminated with organic compounds in the air, cleaning methods may be critical for SAM formation. In this study, we examined the effects of four gold cleaning methods: dilute aqua regia, an ozone water, atmospheric plasma, and UV irradiation. Among the methods, UV irradiation most significantly improved the formation of oligopeptide SAMs in terms of repulsion of cells on the surfaces. We fabricated an apparatus with a UV light source, a rotation table, and HEPA filter, to treat a number of gold substrates simultaneously. Furthermore, UV-cleaned gold substrates were capable of detaching cell sheets without serious cell injury. This may potentially provide a stable and robust approach to oligopeptide SAM-based experiments for biomedical studies. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Preparation of SmBCO layer for the surface optimization of GdYBCO film by MOCVD process based on a simple self-heating technology

NASA Astrophysics Data System (ADS)

Zhao, Ruipeng; Zhang, Fei; Liu, Qing; Xia, Yudong; Lu, Yuming; Cai, Chuanbing; Tao, Bowan; Li, Yanrong

2018-07-01

The MOCVD process was adopted to grow the REBa2Cu3O7-δ ((REBCO), RE = rare earth elements) films on the LaMnO3 (LMO) templates. Meanwhile, the LMO-template tapes are heated by the joule effect after applying a heating current through the Hastelloy metal substrates. The surface of GdYBCO films prepared by MOCVD method is prone to form outgrowths. So the surface morphology of GdYBCO film is optimized by depositing the SmBCO layer, which is an important process method for the preparation of high-quality multilayer REBCO films. At last, the GdYBCO/SmBCO/GdYBCO multilayer films were successfully prepared on the LMO templates based on the simple self-heating method. It is demonstrated that the GdYBCO surface was well improved by the characterization analysis of scanning electron microscope. And the Δω of REBCO (005) and Δφ of REBCO (103), which were performed by an X-ray diffraction system, are respectively 1.3° and 3.3° What's more, the critical current density (Jc) has been more than 3 MA/cm2 (77 K, 0 T) and the critical current (Ic) basically shows a trend of good linear increase with the increase of the number of REBCO layers.

Preparing high-density polymer brushes by mechanically assisted polymer assembly (MAPA)

NASA Astrophysics Data System (ADS)

Wu, Tao; Efimenko, Kirill; Genzer, Jan

2001-03-01

We introduce a novel method of modifying the surface properties of materials. This technique, called MAPA (="mechanically assisted polymer assembly"), is based on: 1) chemically attaching polymerization initiators to the surface of an elastomeric network that has been previously stretched by a certain length, Δx, and 2) growing end-anchored macromolecules using surface initiated ("grafting from") atom transfer living radical polymerization. After the polymerization, the strain is removed from the substrate, which returns to its original size causing the grafted macromolecules to stretch away from the substrate and form a dense polymer brush. We demonstrate the feasibility of the MAPA method by preparing high-density polymer brushes of poly(acryl amide), PAAm. We show that, as expected, the grafting density of the PAAm brushes can be increased by increasing Δx. We demonstrate that polymer brushes with extremely high grafting densities can be successfully prepared by MAPA.

Development of albumin-based nanoparticles for the delivery of abacavir.

PubMed

Wilson, Barnabas; Paladugu, Latishkumar; Priyadarshini, S R Brahmani; Jenita, J Josephine Leno

2015-11-01

The study was designed to prepare and evaluate albumin nanoparticles containing antiviral drug abacavir sulphate. Various batches of albumin nanoparticles containing abacavir sulphate were prepared by desolvation method. The abacavir loaded particles were characterized for their yield, percentage of drug loading, surface morphology, particle size, surface charge, pattern of in vitro drug release and release mechanism studies. Drug loading ranged from 1.2 to 5.9%w/w. The mean particle size and the surface charge were 418.2nm and -40.8mV respectively. The in vitro drug release varied between 38.73 and 51.36%w/w for 24h. The n value for Korsmeyer-Peppas was 0.425 indicating Fickian type drug release. The preliminary findings indicated that albumin nanoparticles of abacavir can be prepared by desolvation method with good yield, high drug loading and sustained release. Copyright © 2015 Elsevier B.V. All rights reserved.

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.

SEVERAL METHODS FOR PREPARING RADIOACTIVE STANDARDS FOR ALPHA AND BETA URANIUM SOURCES (in Serbo-Croatian)

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

Nemoda, D.

1963-03-01

Electrolytic methods for obtaining U radiation sources are described. The radiochemical and electrochemical characteristics of U are described which permit the preparation of a thin or a thick oxide saturation layer on the cathode. Experiments are described representing the deposit of U on metallic surfaces by acido-suifuric solutions with adapted acidity. The influence of acidity, temperature, concentration, reaction period, and surface size was studied. Under the optimal (NH/sub 4/)2CO/sub 3/ acidity, Fe, Al, and Cu are receptive in that order. (OID)

SERS spectra of pyridine adsorbed on nickel film prepared by magnetron sputtering

NASA Astrophysics Data System (ADS)

Li, Daoyong; Ouyang, Yu; Chen, Li; Cao, Weiran; Shi, Shaohua

2011-02-01

As a repeating well and cheaper enhancement substrate, the nickel film was fabricated with magnetron sputtering coating instrument. Surface enhanced Raman spectra (SERS) of pyridine adsorbed on this nickel film are compared with the experimental values of gaseous pyridine, the theoretical value of pyridine solution listed in other literatures and our method is better than electro-chemical etching electrode method for large scale preparation. The enhancement factor of the nickel film is calculated and the result indicates that magnetron sputtering coating technology is feasible for obtaining good SERS active surface.

Method for preparing a thick film conductor

DOEpatents

Nagesh, Voddarahalli K.; Fulrath, deceased, Richard M.

1978-01-01

A method for preparing a thick film conductor which comprises providing surface active glass particles, mixing the surface active glass particles with a thermally decomposable organometallic compound, for example, a silver resinate, and then decomposing the organometallic compound by heating, thereby chemically depositing metal on the glass particles. The glass particle mixture is applied to a suitable substrate either before or after the organometallic compound is thermally decomposed. The resulting system is then fired in an oxidizing atmosphere, providing a microstructure of glass particles substantially uniformly coated with metal.

Method for the preparation of carbon fiber from polyolefin fiber precursor

DOEpatents

Naskar, Amit Kumar; Hunt, Marcus Andrew; Saito, Tomonori

2017-11-28

Methods for the preparation of carbon fiber from polyolefin fiber precursor, wherein the polyolefin fiber precursor is partially sulfonated and then carbonized to produce carbon fiber. Methods for producing hollow carbon fibers, wherein the hollow core is circular- or complex-shaped, are also described. Methods for producing carbon fibers possessing a circular- or complex-shaped outer surface, which may be solid or hollow, are also described.

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.

Microprocessing of human hard tooth tissues surface by mid-infrared erbium lasers radiation

NASA Astrophysics Data System (ADS)

Belikov, Andrey V.; Shatilova, Ksenia V.; Skrypnik, Alexei V.

2015-03-01

A new method of hard tooth tissues laser treatment is described. The method consists in formation of regular microdefects on tissue surface by mid-infrared erbium laser radiation with propagation ratio M2<2 (Er-laser microprocessing). Proposed method was used for preparation of hard tooth tissues surface before filling for improvement of bond strength between tissues surface and restorative materials, microleakage reduction between tissues surface and restorative materials, and for caries prevention as a result of increasing microhardness and acid resistance of tooth enamel.

Transmission Electron Microscopy (TEM) Sample Preparation of Si(1-x)Gex in c-Plane Sapphire Substrate

NASA Technical Reports Server (NTRS)

Kim, Hyun Jung; Choi, Sang H.; Bae, Hyung-Bin; Lee, Tae Woo

2012-01-01

The National Aeronautics and Space Administration-invented X-ray diffraction (XRD) methods, including the total defect density measurement method and the spatial wafer mapping method, have confirmed super hetero epitaxy growth for rhombohedral single crystalline silicon germanium (Si1-xGex) on a c-plane sapphire substrate. However, the XRD method cannot observe the surface morphology or roughness because of the method s limited resolution. Therefore the authors used transmission electron microscopy (TEM) with samples prepared in two ways, the focused ion beam (FIB) method and the tripod method to study the structure between Si1-xGex and sapphire substrate and Si1?xGex itself. The sample preparation for TEM should be as fast as possible so that the sample should contain few or no artifacts induced by the preparation. The standard sample preparation method of mechanical polishing often requires a relatively long ion milling time (several hours), which increases the probability of inducing defects into the sample. The TEM sampling of the Si1-xGex on sapphire is also difficult because of the sapphire s high hardness and mechanical instability. The FIB method and the tripod method eliminate both problems when performing a cross-section TEM sampling of Si1-xGex on c-plane sapphire, which shows the surface morphology, the interface between film and substrate, and the crystal structure of the film. This paper explains the FIB sampling method and the tripod sampling method, and why sampling Si1-xGex, on a sapphire substrate with TEM, is necessary.

Methods for the preparation of protein-oligonucleotide-lipid constructs.

PubMed

Takasaki, Jennifer; Raney, Sameersingh G; Chikh, Ghania; Sekirov, Laura; Brodsky, Irina; Tam, Ying; Ansell, Steven M

2006-01-01

A mixture of ionizable cationic lipids, steric barrier lipids, and colipids is used to encapsulate oligonucleotide DNA in lipidic particles called SALP. This material is under development as an adjuvant for vaccines. Previously we have shown that coupling the antigen directly to the surface of SALP can lead to enhanced immunological responses in vivo. Two different methods for preparing ovalbumin-SALP were assessed in this work. Originally the conjugates were prepared by treating SALP containing a maleimide-derivatized lipid with thiolated ovalbumin, a method we refer to as active coupling. This reaction was found to be difficult to control and generally resulted in low coupling efficiencies. The issues relating to this approach were characterized. We have recently developed alternative techniques based on first coupling ovalbumin to a micelle and then incubating the resultant product with SALP, methods we refer to as passive coupling. We have shown that this method allows accurate control of the levels of protein associated SALP and does not suffer from surface saturation effects seen with the active coupling method that places maximum limits on the amount of protein that can be coupled to the SALP surface. The products from the passive coupling protocol are shown to have activity comparable to those derived from the active coupling protocol in investigations of in vivo immune responses.

Activated carbon with excellent chromium(VI) adsorption performance prepared by acid-base surface modification.

PubMed

Liu, S X; Chen, X; Chen, X Y; Liu, Z F; Wang, H L

2007-03-06

In the present work, activated carbon (AC) with excellent Cr(VI) adsorption performance especially at low concentrations was prepared by an acid-base surface modification method. Raw activated carbon (AC(0)) was first oxidized in boiling HNO(3) (AC(1)), then treated with a mixture of NaOH and NaCl (AC(2)). Batch equilibrium and continuous column adsorption were conducted to evaluate the adsorption performance. Boehm titration, elemental analysis, and N(2)/77K adsorption isotherm methods were used to characterize the surface properties and pore structure of modified ACs. The results revealed that the modified AC exhibited excellent Cr(VI) adsorption performance in terms of adsorption capacity and adsorption rate: AC(2)>AC(1)>AC(0). Modification caused S(BET) to decrease and the total number of surface oxygen acidic groups to increase. HNO(3) oxidization produced positive acid groups, and subsequently NaOH treatment replaced H(+) of surface acid groups by Na(+), and the acidity of AC decreased. The main cause of higher Cr(VI) adsorption capacity and rate for AC(2) was the presence of more oxygen surface acidic groups and suitable surface acidity. HNO(3)-NaOH modification shows potential for the preparation of high quality AC for the effective removal of low concentrations of Cr(VI).

Effects of surface preparation on the long-term durability of adhesively bonded composite joints

NASA Astrophysics Data System (ADS)

Bardis, Jason Dante

The long-term durability of adhesively bonded composite joints is critical to modern aircraft structures, which are increasingly adopting bonding as an alternative option to mechanical fastening. The effects of the surface preparation of the adherends are critical, affecting initial strength, long-term durability, fracture toughness, and failure modes of bonded joints. In this study, several potential factors are evaluated, with focus on the following: (1) Effects of possible chemical contamination from release fabrics, release films, and peel plies during adherend cure. (2) Chemical and mechanical effects of abrasion on the fracture toughness and failure mode. (3) Characterization of paste and film adhesives. There are several standard test methods used to evaluate specimen fracture, but the majority concentrate on bonded metals and interlaminar composite fracture. Testing concentrated on mode I tests; a custom double cantilever beam specimen was devised and utilized, and two forms of a wedge crack test (traveling and static) were also used. Additionally, single lap shear tests were run to contrast the mode I tests. Non-destructive testing included X-ray photography of crack fronts, energy dispersive spectroscopy and X-ray photoelectron spectroscopy surface chemistry analyses, and scanning electron microscope imaging of prepared surfaces. All mode I test methods tended to be in agreement in the ranking of different surface preparation methods. Test results revealed that release agents deposited on adherend surfaces during their cure cycle prevented proper adhesion. While mechanical abrasion did improve their fracture toughness and lower their contamination greatly, the test values did not reach the levels of samples that were not contaminated before bonding, and the interfacial modes of failure did not always change to desirable modes.

Method for the preparation of high surface area high permeability carbons

DOEpatents

Lagasse, Robert R.; Schroeder, John L.

1999-05-11

A method for preparing carbon materials having high surface area and high macropore volume to provide high permeability. These carbon materials are prepared by dissolving a carbonizable polymer precursor, in a solvent. The solution is cooled to form a gel. The solvent is extracted from the gel by employing a non-solvent for the polymer. The non-solvent is removed by critical point drying in CO.sub.2 at an elevated pressure and temperature or evaporation in a vacuum oven. The dried product is heated in an inert atmosphere in a first heating step to a first temperature and maintained there for a time sufficient to substantially cross-link the polymer material. The cross-linked polymer material is then carbonized in an inert atmosphere.

Artificial receptor-functionalized nanoshell: facile preparation, fast separation and specific protein recognition

NASA Astrophysics Data System (ADS)

Ouyang, Ruizhuo; Lei, Jianping; Ju, Huangxian

2010-05-01

This work combined molecular imprinting technology with superparamagnetic nanospheres as the core to prepare artificial receptor-functionalized magnetic nanoparticles for separation of homologous proteins. Using dopamine as a functional monomer, novel surface protein-imprinted superparamagnetic polydopamine (PDA) core-shell nanoparticles were successfully prepared in physiological conditions, which could maintain the natural structure of a protein template and achieved the development of molecularly imprinted polymers (MIPs) from one dimension to zero dimension for efficient recognition towards large biomolecules. The resultant nanoparticles could be used for convenient magnetic separation of homologous proteins with high specificity. The nanoparticles possessed good monodispersibility, uniform surface morphology and high saturation magnetization value. The bound amounts of template proteins measured by both indirect and direct methods were in good agreement. The maximum number of imprinted cavities on the surface of the bovine hemoglobin (Hb)-imprinted nanoshell was 2.21 × 1018 g - 1, which well matched their maximum binding capacity toward bovine Hb. Both the simple method for preparation of MIPs and the magnetic nanospheres showed good application potential in fast separation, effective concentration and selective biosensing of large protein molecules.

[Spectral studies on nano-sized titania photocatalysts prepared by different drying methods].

PubMed

Ye, Zhao; Zhang, Han-hui; Pan, Hai-bo; Pan, Hong-qing

2002-12-01

Nano-sized TiO2 photocatalysts were prepared by drying the ethanol gel of titanium tetrabutoxide through natural state, supercritical ethanol, supercritical carbon dioxide drying methods and characterized by XRD, FTIR spectroscopy, FT-Raman spectroscopy and fluorescent spectroscopy, respectively. We regard degradation of rhodamine B by photocatalyst as a model reaction, and compare photocatalytic activities of samples obtained. The experimental results show that different drying methods have strong effect on crystal structure, energy band structure, optical adsorption property, surface quality and photocatalytic activity, TiO2 photocatalyst prepared by supercritical carbon dioxide drying method has superior photocatalytic activity.

Surface preparation effects on GTA weld shape in JBK-75 stainless steel

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

Campbell, R.D.; Robertson, A.M.; Heiple, C.R.

1993-02-01

The results of a study are reported here on the effects of surface preparation on the shape of autogenous gas tungsten arc (GTA) welds in JBK-75, an austenitic precipitation hardenable stainless steel similar to A286. Minor changes in surface preparation produced substantial changes in the fusion zone shape and welding behavior of this alloy. Increased and more consistent depth of fusion (higher d/w ratios) along with improved arc stability and less arc wander resulted from wire brushing and other abrasive surface preparations, although chemical and machining methods did not produce any increase in depth of fusion. Abrasive treatments roughen themore » surface, increase the surface area, increase the surface oxide thickness, and entrap oxide. The increased weld d/w ratio is attributed to oxygen added to the weld pool from the surface oxide on the base metal. The added oxygen alters the surface-tension-driven fluid flow pattern in the weld pool. Increased depth of fusion in wire-fed U-groove weld joints also resulted when welding wire with a greater surface oxide thickness was used. Increasing the amount of wire brushing produced even deeper welds. However, a maximum in depth of fusion was observed with further wire brushing, beyond which weld fusion depth decreased.« less

Quantification of ligand density and stoichiometry on the surface of liposomes using single-molecule fluorescence imaging.

PubMed

Belfiore, Lisa; Spenkelink, Lisanne M; Ranson, Marie; van Oijen, Antoine M; Vine, Kara L

2018-05-28

Despite the longstanding existence of liposome technology in drug delivery applications, there have been no ligand-directed liposome formulations approved for clinical use to date. This lack of translation is due to several factors, one of which is the absence of molecular tools for the robust quantification of ligand density on the surface of liposomes. We report here for the first time the quantification of proteins attached to the surface of small unilamellar liposomes using single-molecule fluorescence imaging. Liposomes were surface-functionalized with fluorescently labeled human proteins previously validated to target the cancer cell surface biomarkers plasminogen activator inhibitor-2 (PAI-2) and trastuzumab (TZ, Herceptin®). These protein-conjugated liposomes were visualized using a custom-built wide-field fluorescence microscope with single-molecule sensitivity. By counting the photobleaching steps of the fluorescently labeled proteins, we calculated the number of attached proteins per liposome, which was 11 ± 4 proteins for single-ligand liposomes. Imaging of dual-ligand liposomes revealed stoichiometries of the two attached proteins in accordance with the molar ratios of protein added during preparation. Preparation of PAI-2/TZ dual-ligand liposomes via two different methods revealed that the post-insertion method generated liposomes with a more equal representation of the two differently sized proteins, demonstrating the ability of this preparation method to enable better control of liposome protein densities. We conclude that the single-molecule imaging method presented here is an accurate and reliable quantification tool for determining ligand density and stoichiometry on the surface of liposomes. This method has the potential to allow for comprehensive characterization of novel ligand-directed liposomes that should facilitate the translation of these nanotherapies through to the clinic. Copyright © 2018 Elsevier B.V. All rights reserved.

Method for the preparation of carbon fiber from polyolefin fiber precursor, and carbon fibers made thereby

DOEpatents

Naskar, Amit Kumar; Hunt, Marcus Andrew; Saito, Tomonori

2015-08-04

Methods for the preparation of carbon fiber from polyolefin fiber precursor, wherein the polyolefin fiber precursor is partially sulfonated and then carbonized to produce carbon fiber. Methods for producing hollow carbon fibers, wherein the hollow core is circular- or complex-shaped, are also described. Methods for producing carbon fibers possessing a circular- or complex-shaped outer surface, which may be solid or hollow, are also described.

Preparation of core-shell Ag@CeO2 nanocomposite by LSPR photothermal induced interface reaction

NASA Astrophysics Data System (ADS)

Zhong, H. X.; Wei, Y.; Yue, Y. Z.; Zhang, L. H.; Liu, Y.

2016-04-01

The core-shell structure of Ag@CeO2 was prepared by a novel and facile method, which was based on the photothermal effect of localized surface plasmon resonance (LSPR). Nanoparticles (NPs) of Ag were dispersed in a solution containing citric acid, ethylene glycol and cerium nitrate, then under irradiation, Ag NPs generated heat from LSPR and the heat-induced polymerization reaction in the interface between Ag and the sol resulted in cerium gel formation only on the surface of the Ag NPs. After calcination, Ag@CeO2 was successfully obtained, then Ag@CeO2/SiO2 was prepared by loading Ag@CeO2 on SiO2. The resultant catalyst exhibited favorable activity and stability for CO oxidation. The preparation method proposed here should be extendable to other composites with metallic cores and oxide shells in which the metallic nanoparticle possesses LSPR properties.

Solid-State Division progress report for period ending March 31, 1983

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

Green, P.H.; Watson, D.M.

1983-09-01

Progress and activities are reported on: theoretical solid-state physics (surfaces; electronic, vibrational, and magnetic properties; particle-solid interactions; laser annealing), surface and near-surface properties of solids (surface, plasma-material interactions, ion implantation and ion-beam mixing, pulsed-laser and thermal processing), defects in solids (radiation effects, fracture, impurities and defects, semiconductor physics and photovoltaic conversion), transport properties of solids (fast-ion conductors, superconductivity, mass and charge transport in materials), neutron scattering (small-angle scattering, lattice dynamics, magnetic properties, structure and instrumentation), and preparation and characterization of research materials (growth and preparative methods, nuclear waste forms, special materials). (DLC)

Nanopatterned articles produced using surface-reconstructed block copolymer films

DOEpatents

Russell, Thomas P.; Park, Soojin; Wang, Jia-Yu; Kim, Bokyung

2016-06-07

Nanopatterned surfaces are prepared by a method that includes forming a block copolymer film on a substrate, annealing and surface reconstructing the block copolymer film to create an array of cylindrical voids, depositing a metal on the surface-reconstructed block copolymer film, and heating the metal-coated block copolymer film to redistribute at least some of the metal into the cylindrical voids. When very thin metal layers and low heating temperatures are used, metal nanodots can be formed. When thicker metal layers and higher heating temperatures are used, the resulting metal structure includes nanoring-shaped voids. The nanopatterned surfaces can be transferred to the underlying substrates via etching, or used to prepare nanodot- or nanoring-decorated substrate surfaces.

Surface-enhanced Raman scattering (SERS) spectra of sodium benzoate and 4-picoline in Ag colloids prepared by γ-irradiation

NASA Astrophysics Data System (ADS)

Choi, Seong-Ho; Park, Hyun Gyu

2005-04-01

PVP-protected silver colloids were prepared by γ-irradiation and chemical reduction method. Surface-enhanced Raman scattering (SERS) spectra of sodium benzoate and 4-picoline in Ag colloids prepared by γ-irradiation were recorded. The SERS spectra of sodium benzoate were successfully recorded in Ag colloids, whereas the Raman spectra did not appear without Ag colloids. The Raman spectra of 4-picoline were not detected without Ag colloids, while the SERS spectra of 4-picoline were increased by adding Ag colloids. The carboxylate group of sodium benzoate and N donor of 4-picoline were adsorbed on the surface of Ag nanoparticles.

A novel preparation method for silicone oil nanoemulsions and its application for coating hair with silicone

PubMed Central

Hu, Zhenhua; Liao, Meiling; Chen, Yinghui; Cai, Yunpeng; Meng, Lele; Liu, Yajun; Lv, Nan; Liu, Zhenguo; Yuan, Weien

2012-01-01

Background Silicone oil, as a major component in conditioner, is beneficial in the moisture preservation and lubrication of hair. However, it is difficult for silicone oil to directly absorb on the hair surface because of its hydrophobicity. Stable nanoemulsions containing silicone oil may present as a potential solution to this problem. Methods Silicone oil nanoemulsions were prepared using the oil-in-water method with nonionic surfactants. Emulsion particle size and distribution were characterized by scanning electron microscopy. The kinetic stability of this nanoemulsion system was investigated under accelerated stability tests and long-term storage. The effect of silicone oil deposition on hair was examined by analyzing the element of hair after treatment of silicone oil nanoemulsions. Results Nonionic surfactants such as Span 80 and Tween 80 are suitable emulsifiers to prepare oil-in-water nanoemulsions that are both thermodynamically stable and can enhance the absorption of silicone oil on hair surface. Conclusion The silicone oil-in-water nanoemulsions containing nonionic surfactants present as a promising solution to improve the silicone oil deposition on the hair surface for hair care applications. PMID:23166436

Hydroxide-catalyzed bonding

NASA Technical Reports Server (NTRS)

Gwo, Dz-Hung (Inventor)

2003-01-01

A method of bonding substrates by hydroxide-catalyzed hydration/dehydration involves applying a bonding material to at least one surface to be bonded, and placing the at least one surface sufficiently close to another surface such that a bonding interface is formed between them. A bonding material of the invention comprises a source of hydroxide ions, and may optionally include a silicate component, a particulate filling material, and a property-modifying component. Bonding methods of the invention reliably and reproducibly provide bonds which are strong and precise, and which may be tailored according to a wide range of possible applications. Possible applications for bonding materials of the invention include: forming composite materials, coating substrates, forming laminate structures, assembly of precision optical components, and preparing objects of defined geometry and composition. Bonding materials and methods of preparing the same are also disclosed.

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.

Preparation and evaluation of diblock copolymer-grafted silica by sequential surface initiated-atom transfer radical polymerization for reverse-phase/ion-exchange mixed-mode chromatography.

PubMed

Bo, Chun Miao; Wang, Chaozhan; Wei, Yin Mao

2017-12-01

A novel approach that involved the grafting of diblock copolymer with two types of monomer onto substrate by sequential surface initiated-atom transfer radical polymerization was proposed to prepare a mixed-mode chromatographic stationary phase. The distinguishing feature of this method is that it can be applied in the preparation of various mixed-mode stationary phases. In this study, a new reverse-phase/ion-exchange stationary phase was prepared by grafting hydrophobic styrene and cationic sodium 4-styrenesulfonate by the proposed approach onto silica surface. The chromatographic properties of the prepared stationary phase were evaluated by the separation of benzene derivatives, anilines, and β-agonists, and by the effect of pH values and acetonitrile content on the retention. Compared with typical RP columns, the prepared stationary phase achieved the better resolution and higher selectivity at a shorter separation time and lower organic content. Moreover, the application of the prepared column was proved by separating widely distributed polar and charged compounds simultaneously. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

On-machine precision preparation and dressing of ball-headed diamond wheel for the grinding of fused silica

NASA Astrophysics Data System (ADS)

Chen, Mingjun; Li, Ziang; Yu, Bo; Peng, Hui; Fang, Zhen

2013-09-01

In the grinding of high quality fused silica parts with complex surface or structure using ball-headed metal bonded diamond wheel with small diameter, the existing dressing methods are not suitable to dress the ball-headed diamond wheel precisely due to that they are either on-line in process dressing which may causes collision problem or without consideration for the effects of the tool setting error and electrode wear. An on-machine precision preparation and dressing method is proposed for ball-headed diamond wheel based on electrical discharge machining. By using this method the cylindrical diamond wheel with small diameter is manufactured to hemispherical-headed form. The obtained ball-headed diamond wheel is dressed after several grinding passes to recover geometrical accuracy and sharpness which is lost due to the wheel wear. A tool setting method based on high precision optical system is presented to reduce the wheel center setting error and dimension error. The effect of electrode tool wear is investigated by electrical dressing experiments, and the electrode tool wear compensation model is established based on the experimental results which show that the value of wear ratio coefficient K' tends to be constant with the increasing of the feed length of electrode and the mean value of K' is 0.156. Grinding experiments of fused silica are carried out on a test bench to evaluate the performance of the preparation and dressing method. The experimental results show that the surface roughness of the finished workpiece is 0.03 μm. The effect of the grinding parameter and dressing frequency on the surface roughness is investigated based on the measurement results of the surface roughness. This research provides an on-machine preparation and dressing method for ball-headed metal bonded diamond wheel used in the grinding of fused silica, which provides a solution to the tool setting method and the effect of electrode tool wear.

Flat ion milling: a powerful tool for preparation of cross-sections of lead-silver alloys.

PubMed

Brodusch, Nicolas; Boisvert, Sophie; Gauvin, Raynald

2013-06-01

While conventional mechanical and chemical polishing results in stress, deformation and polishing particles embedded on the surface, flat milling with Ar+ ions erodes the material with no mechanical artefacts. This flat milling process is presented as an alternative method to prepare a Pb-Ag alloy cross-section for scanning electron microscopy. The resulting surface is free of scratches with very little to no stress induced, so that electron diffraction and channelling contrast are possible. The results have shown that energy dispersive spectrometer (EDS) mapping, electron channelling contrast imaging and electron backscatter diffraction can be conducted with only one sample preparation step. Electron diffraction patterns acquired at 5 keV possessed very good pattern quality, highlighting an excellent surface condition. An orientation map was acquired at 20 keV with an indexing rate of 90.1%. An EDS map was performed at 5 keV, and Pb-Ag precipitates of sizes lower than 100 nm were observed. However, the drawback of the method is the generation of a noticeable surface topography resulting from the interaction of the ion beam with a polycrystalline and biphasic sample.

Ultrathin Carbon Film Protected Silver Nanostructures for Surface-Enhanced Raman Scattering.

PubMed

Peng, Yinshan; Zheng, Xianliang; Tian, Hongwei; Cui, Xiaoqiang; Chen, Hong; Zheng, Weitao

2016-06-23

In this article, ultrathin carbon film protected silver substrate (Ag/C) was prepared via a plasma-enhanced chemical vapor deposition (PECVD) method. The morphological evolution of silver nanostructures underneath, as well as the surface-enhanced Raman scattering (SERS) activity of Ag/C hybrid can be tuned by controlling the deposition time. The stability and reproducibility of the as-prepared hybrid were also studied. © The Author(s) 2016.

Polythiophene thin films by surface-initiated polymerization: Mechanistic and structural studies

DOE PAGES

Youm, Sang Gil; Hwang, Euiyong; Chavez, Carlos A.; ...

2016-06-15

The ability to control nanoscale morphology and molecular organization in organic semiconducting polymer thin films is an important prerequisite for enhancing the efficiency of organic thin-film devices including organic light-emitting and photovoltaic devices. The current “top-down” paradigm for making such devices is based on utilizing solution-based processing (e.g., spin-casting) of soluble semiconducting polymers. This approach typically provides only modest control over nanoscale molecular organization and polymer chain alignment. A promising alternative to using solutions of presynthesized semiconducting polymers pursues instead a “bottom-up” approach to prepare surface-grafted semiconducting polymer thin films by surface-initiated polymerization of small-molecule monomers. Herein, we describe themore » development of an efficient method to prepare polythiophene thin films utilizing surface-initiated Kumada catalyst transfer polymerization. In this study, we provided evidence that the surface-initiated polymerization occurs by the highly robust controlled (quasi-“living”) chain-growth mechanism. Further optimization of this method enabled reliable preparation of polythiophene thin films with thickness up to 100 nm. Extensive structural studies of the resulting thin films using X-ray and neutron scattering methods as well as ultraviolet photoemission spectroscopy revealed detailed information on molecular organization and the bulk morphology of the films, and enabled further optimization of the polymerization protocol. One of the remarkable findings was that surface-initiated polymerization delivers polymer thin films showing complex molecular organization, where polythiophene chains assemble into lateral crystalline domains of about 3.2 nm size, with individual polymer chains folded to form in-plane aligned and densely packed oligomeric segments (7-8 thiophene units per each segment) within each domain. Achieving such a complex mesoscale organization is virtually impossible with traditional methods relying on solution processing of presynthesized polymers. Another significant advantage of surface-confined polymer thin films is their remarkable stability toward organic solvents and other processing conditions. In addition to controlled bulk morphology, uniform molecular organization, and stability, a unique feature of the surface-initiated polymerization is that it can be used for the preparation of large-area uniformly nanopatterned polymer thin films. Lastly, this was demonstrated using a combination of particle lithography and surface-initiated polymerization. In general, surface-initiated polymerization is not limited to polythiophene but can be also expanded toward other classes of semiconducting polymers and copolymers.« less

Li-cycling properties of molten salt method prepared nano/submicrometer and micrometer-sized CuO for lithium batteries.

PubMed

Reddy, M V; Yu, Cai; Jiahuan, Fan; Loh, Kian Ping; Chowdari, B V R

2013-05-22

We report the synthesis of CuO material by molten salt method at a temperature range, 280 to 950 °C for 3 h in air. This report includes studies on the effect of morphology, crystal structure and electrochemical properties of CuO prepared at different temperatures. Obtained CuO was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area methods. Samples prepared at ≥410 °C showed a single-phase material with a lattice parameter value of a = 4.69 Å, b = 3.43 Å, c = 5.13 Å and surface area values are in the range 1.0-17.0 m(2) g(-1). Electrochemical properties were evaluated via cyclic voltammetry (CV) and galvanostatic cycling studies. CV studies showed a minor difference in the peak potentials depending on preparation temperature and all compounds exhibit a main anodic peak at ~2.45 V and cathodic peaks at ~0.85 V and ~1.25 V vs Li. CuO prepared at 750 °C showed high and stable capacity of ~620 mA h g(-1) at the end of 40th cycle.

Quantitative Methods Based on Twisted Nematic Liquid Crystals for Mapping Surfaces Patterned with Bio/Chemical Functionality Relevant to Bioanalytical Assays

PubMed Central

Lowe, Aaron M.; Bertics, Paul J.; Abbott, Nicholas L.

2009-01-01

We report methods for the acquisition and analysis of optical images formed by thin films of twisted nematic liquid crystals (LCs) placed into contact with surfaces patterned with bio/chemical functionality relevant to surface-based assays. The methods are simple to implement and are shown to provide easily interpreted maps of chemical transformations on surfaces that are widely exploited in the preparation of analytic devices. The methods involve acquisition of multiple images of the LC as a function of the orientation of a polarizer; data analysis condenses the information present in the stack of images into a spatial map of the twist angle of the LC on the analytic surface. The potential utility of the methods is illustrated by mapping (i) the displacement of a monolayer formed from one alkanethiol on a gold film by a second thiol in solution, (ii) coadsorption of mixtures of amine-terminated and ethyleneglycol-terminated alkanethiols on gold films, which leads to a type of mixed monolayer that is widely exploited for immobilization of proteins on analytic surfaces, and (iii) patterns of antibodies printed onto surfaces. These results show that maps of the twist angle of the LC constructed from families of optical images can be used to reveal surface features that are not apparent in a single image of the LC film. Furthermore, the twist angles of the LC can be used to quantify the energy of interaction of the LC with the surface with a spatial resolution of <10 µm. When combined, the results described in this paper suggest non-destructive methods to monitor and validate chemical transformations on surfaces of the type that are routinely employed in the preparation of surface-based analytic technologies. PMID:18355089

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.

Clinical Evaluation of Different Pre-impression Preparation Procedures of Dental Arch

PubMed Central

Arora, Nitin; Arora, Monika; Gupta, Naveen; Agarwal, Manisha; Verma, Rohit; Rathod, Pankaj

2015-01-01

Background: Bubbles and voids on the occlusal surface impede the actual intercuspation and pre-impression preparation aims to reduce the incidence of air bubbles and voids as well as influences the quality of occlusal reproduction and actual clinical intercuspation in the articulator. The study was undertaken to determine the influence of different pre-impression preparation procedures of antagonistic dental arch on the quality of the occlusal reproduction of the teeth in irreversible hydrocolloid impressions and to determine most reliable pre-impression preparation method to reduce the incidence of air bubbles. Materials and Methods: A total of 20 subjects were selected having full complement of mandibular teeth from second molar to second molar with well demarcated cusp height. 200 impressions were made with irreversible hydrocolloid material. The impressions were divided into five groups of 40 impressions each and each group had one specific type of pre-impression preparation. All the impressions were poured in die stone. A stereomicroscope with graduated eyepiece was used to count the number of bubbles on the occlusal surface of premolars and molars. The mean and standard deviations were calculated for each group. Mann–Whitney U-test was applied to find the significant difference between different groups. Results: Least bubbles were found in the group in which oral cavity was dried by saliva ejector and fluid hydrocolloid was finger painted onto the occlusal surfaces immediately before the placement of impression tray in the mouth. Conclusion: It was found that finger painting the tooth surfaces with fluid hydrocolloid immediately before the placement of loaded impression tray in the mouth was the most reliable method. The oral cavity can be cleared more easily of excess saliva by vacuum suction rather than by use of an astringent solution. PMID:26229376

Bimetallic alloy electrocatalysts with multilayered platinum-skin surfaces

DOEpatents

Stamenkovic, Vojislav R.; Wang, Chao; Markovic, Nenad M.

2016-01-26

Compositions and methods of preparing a bimetallic alloy having enhanced electrocatalytic properties are provided. The composition comprises a PtNi substrate having a surface layer, a near-surface layer, and an inner layer, where the surface layer comprises a nickel-depleted composition, such that the surface layer comprises a platinum skin having at least one atomic layer of platinum.

Method for the preparation of high surface area high permeability carbons

DOEpatents

Lagasse, R.R.; Schroeder, J.L.

1999-05-11

A method for preparing carbon materials having high surface area and high macropore volume to provide high permeability. These carbon materials are prepared by dissolving a carbonizable polymer precursor, in a solvent. The solution is cooled to form a gel. The solvent is extracted from the gel by employing a non-solvent for the polymer. The non-solvent is removed by critical point drying in CO{sub 2} at an elevated pressure and temperature or evaporation in a vacuum oven. The dried product is heated in an inert atmosphere in a first heating step to a first temperature and maintained there for a time sufficient to substantially cross-link the polymer material. The cross-linked polymer material is then carbonized in an inert atmosphere. 3 figs.

Hydrogen production by steam reforming of liquefied natural gas over a nickel catalyst supported on mesoporous alumina xerogel

NASA Astrophysics Data System (ADS)

Seo, Jeong Gil; Youn, Min Hye; Cho, Kyung Min; Park, Sunyoung; Song, In Kyu

Mesoporous alumina xerogel (A-SG) is prepared by a sol-gel method for use as a support for a nickel catalyst. The Ni/A-SG catalyst is then prepared by an impregnation method, and is applied to hydrogen production by steam reforming of liquefied natural gas (LNG). The effect of the mesoporous alumina xerogel support on the catalytic performance of Ni/A-SG catalyst is investigated. For the purpose of comparison, a nickel catalyst supported on commercial alumina (A-C) is also prepared by an impregnation method (Ni/A-C). Both the hydroxyl-rich surface and the electron-deficient sites of the A-SG support enhance the dispersion of the nickel species on the support during the calcination step. The formation of the surface nickel aluminate phase in the Ni/A-SG catalyst remarkably increases the reducibility and stability of the catalyst. Furthermore, the high-surface area and the well-developed mesoporosity of the Ni/A-SG catalyst enhance the gasification of surface hydrocarbons that are adsorbed in the reaction. In the steam reforming of LNG, the Ni/A-SG catalyst exhibits a better catalytic performance than the Ni/A-C catalyst in terms of LNG conversion and hydrogen production. Moreover, the Ni/A-SG catalyst shows strong resistance toward catalyst deactivation.

Transient bleaching of small PbS colloids. Influence of surface properties

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

Nenadovic, M.T.; Comor, M.I.; Vasic, V.

1990-08-09

Small PbS colloids with a particle diameter of 40 {angstrom} were prepared in aqueous solution, and their absorption spectra exhibit several maxima. Injection of electrons into these particles was achieved by using the pulse radiolysis technique. Excess electrons trapped on the surface lead to a blue shift in the absorption edge of colloids. The appearance of this shift depends critically on the method of colloid preparation. PbS and CdS colloids prepared at pH < 6 have long-lived bleaching, which disappears after several seconds. On the other hand, absorption bleaching does not appear after the addition of hydroxide ions to colloidalmore » solutions (pH > 8). The existence of a hydroxide ion on the particle surface most likely removes surface defects on which electrons are trapped. PbS colloids prepared in the presence of 3-mercapto-1,2-propanediol have an unstructured absorption spectrum, which is due to a wide particle size distribution (10-50 {angstrom}).« less

One-step electrodeposition process to fabricate corrosion-resistant superhydrophobic surface on magnesium alloy.

PubMed

Liu, Qin; Chen, Dexin; Kang, Zhixin

2015-01-28

A simple, one-step method has been developed to construct a superhydrophobic surface by electrodepositing Mg-Mn-Ce magnesium plate in an ethanol solution containing cerium nitrate hexahydrate and myristic acid. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and Fourier transform infrared spectroscopy were employed to characterize the surfaces. The shortest electrodeposition time to obtain a superhydrophobic surface was about 1 min, and the as-prepared superhydrophobic surfaces had a maximum contact angle of 159.8° and a sliding angle of less than 2°. Potentiodynamic polarization and electrochemical impedance spectroscopy measurements demonstrated that the superhydrophobic surface greatly improved the corrosion properties of magnesium alloy in 3.5 wt % aqueous solutions of NaCl, Na2SO4, NaClO3, and NaNO3. Besides, the chemical stability and mechanical durability of the as-prepared superhydrophobic surface were also examined. The presented method is rapid, low-cost, and environmentally friendly and thus should be of significant value for the industrial fabrication of anticorrosive superhydrophobic surfaces and should have a promising future in expanding the applications of magnesium alloys.

Preparation of protein- and cell-resistant surfaces by hyperthermal hydrogen induced cross-linking of poly(ethylene oxide).

PubMed

Bonduelle, Colin V; Lau, Woon M; Gillies, Elizabeth R

2011-05-01

The functionalization of surfaces with poly(ethylene oxide) (PEO) is an effective means of imparting resistance to the adsorption of proteins and the attachment and growth of cells, properties that are critical for many biomedical applications. In this work, a new hyperthermal hydrogen induced cross-linking (HHIC) method was explored as a simple one-step approach for attaching PEO to surfaces through the selective cleavage of C-H bonds and subsequent cross-linking of the resulting carbon radicals. In order to study the effects of the process on the polymer, PEO-coated silicon wafers were prepared and the effects of different treatment times were investigated. Subsequently, using an optimized treatment time and a modified butyl polymer with increased affinity for PEO, the technique was applied to butyl rubber surfaces. All of the treated surfaces exhibited significantly reduced protein adsorption and cell growth relative to control surfaces and compared favorably with surfaces that were functionalized with PEO using conventional chemical methods. Thus HHIC is a simple and effective means of attaching PEO to non-functional polymer surfaces.

Method for preparing thin-walled ceramic articles of configuration

DOEpatents

Holcombe, C.E.; Powell, G.L.

1975-11-01

A method for preparing a hollow thin-walled ceramic product is described. Ceramic powder is plasma-sprayed onto a concave surface of a substrate having a coefficient of thermal expansion less than that of the ceramic. The coated substrate is heated to sinter the ceramic and then cooled to effect a separation of the ceramic product from the substrate. (auth)

Synthesis of water dispersible boron core silica shell (B@SiO2) nanoparticles

NASA Astrophysics Data System (ADS)

Walton, Nathan I.; Gao, Zhe; Eygeris, Yulia; Ghandehari, Hamidreza; Zharov, Ilya

2018-04-01

Water dispersible boron nanoparticles have great potential as materials for boron neutron capture therapy of cancer and magnetic resonance imaging, if they are prepared on a large scale with uniform size and shape and hydrophilic modifiable surface. We report the first method to prepare spherical, monodisperse, water dispersible boron core silica shell nanoparticles (B@SiO2 NPs) suitable for aforementioned biomedical applications. In this method, 40 nm elemental boron nanoparticles, easily prepared by mechanical milling and carrying 10-undecenoic acid surface ligands, are hydrosilylated using triethoxysilane, followed by base-catalyzed hydrolysis of tetraethoxysilane, which forms a 10-nm silica shell around the boron core. This simple two-step process converts irregularly shaped hydrophobic boron particles into the spherically shaped uniform nanoparticles. The B@SiO2 NPs are dispersible in water and the silica shell surface can be modified with primary amines that allow for the attachment of a fluorophore and, potentially, of targeting moieties. [Figure not available: see fulltext.

Direct organocatalytic enantioselective functionalization of SiOx surfaces.

PubMed

Parkin, John David; Chisholm, Ross; Frost, Aileen B; Bailey, Richard G; Smith, Andrew David; Hähner, Georg

2018-06-05

Traditional methods to prepare chiral surfaces involve either the adsorption of a chiral molecule onto an achiral surface, or adsorption of a species that forms a chiral template creating lattices with long range order. To date only limited alternative strategies to prepare chiral surfaces have been studied. In this manuscript a "bottom up" approach is developed that allows the preparation of chiral surfaces by direct enantioselective organocatalysis on a functionalized Si-oxide supported self-assembled monolayer (SAM). The efficient catalytic generation of enantiomerically enriched organic surfaces is achieved using a commercially available homogeneous isothiourea catalyst (HyperBTM) that promotes an enantioselective Michael-lactonization process upon a Si-oxide supported self-assembled monolayer functionalized with a reactive trifluoroenone group. Chiral atomic force microscopy (chi-AFM) is used to probe the enantiomeric enrichment of the organic films by measurement of the force distributions arising from interaction of D- or L-cysteine modified AFM tips and the organic films. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Youm, Sang Gil; Hwang, Euiyong; Chavez, Carlos A.

The ability to control nanoscale morphology and molecular organization in organic semiconducting polymer thin films is an important prerequisite for enhancing the efficiency of organic thin-film devices including organic light-emitting and photovoltaic devices. The current “top-down” paradigm for making such devices is based on utilizing solution-based processing (e.g., spin-casting) of soluble semiconducting polymers. This approach typically provides only modest control over nanoscale molecular organization and polymer chain alignment. A promising alternative to using solutions of presynthesized semiconducting polymers pursues instead a “bottom-up” approach to prepare surface-grafted semiconducting polymer thin films by surface-initiated polymerization of small-molecule monomers. Herein, we describe themore » development of an efficient method to prepare polythiophene thin films utilizing surface-initiated Kumada catalyst transfer polymerization. In this study, we provided evidence that the surface-initiated polymerization occurs by the highly robust controlled (quasi-“living”) chain-growth mechanism. Further optimization of this method enabled reliable preparation of polythiophene thin films with thickness up to 100 nm. Extensive structural studies of the resulting thin films using X-ray and neutron scattering methods as well as ultraviolet photoemission spectroscopy revealed detailed information on molecular organization and the bulk morphology of the films, and enabled further optimization of the polymerization protocol. One of the remarkable findings was that surface-initiated polymerization delivers polymer thin films showing complex molecular organization, where polythiophene chains assemble into lateral crystalline domains of about 3.2 nm size, with individual polymer chains folded to form in-plane aligned and densely packed oligomeric segments (7-8 thiophene units per each segment) within each domain. Achieving such a complex mesoscale organization is virtually impossible with traditional methods relying on solution processing of presynthesized polymers. Another significant advantage of surface-confined polymer thin films is their remarkable stability toward organic solvents and other processing conditions. In addition to controlled bulk morphology, uniform molecular organization, and stability, a unique feature of the surface-initiated polymerization is that it can be used for the preparation of large-area uniformly nanopatterned polymer thin films. Lastly, this was demonstrated using a combination of particle lithography and surface-initiated polymerization. In general, surface-initiated polymerization is not limited to polythiophene but can be also expanded toward other classes of semiconducting polymers and copolymers.« less

Nano-patterned superconducting surface for high quantum efficiency cathode

DOEpatents

Hannon, Fay; Musumeci, Pietro

2017-03-07

A method for providing a superconducting surface on a laser-driven niobium cathode in order to increase the effective quantum efficiency. The enhanced surface increases the effective quantum efficiency by improving the laser absorption of the surface and enhancing the local electric field. The surface preparation method makes feasible the construction of superconducting radio frequency injectors with niobium as the photocathode. An array of nano-structures are provided on a flat surface of niobium. The nano-structures are dimensionally tailored to interact with a laser of specific wavelength to thereby increase the electron yield of the surface.

Universal Method for Creating Hierarchical Wrinkles on Thin-Film Surfaces.

PubMed

Jung, Woo-Bin; Cho, Kyeong Min; Lee, Won-Kyu; Odom, Teri W; Jung, Hee-Tae

2018-01-10

One of the most interesting topics in physical science and materials science is the creation of complex wrinkled structures on thin-film surfaces because of their several advantages of high surface area, localized strain, and stress tolerance. In this study, a significant step was taken toward solving limitations imposed by the fabrication of previous artificial wrinkles. A universal method for preparing hierarchical three-dimensional wrinkle structures of thin films on a multiple scale (e.g., nanometers to micrometers) by sequential wrinkling with different skin layers was developed. Notably, this method was not limited to specific materials, and it was applicable to fabricating hierarchical wrinkles on all of the thin-film surfaces tested thus far, including those of metals, two-dimensional and one-dimensional materials, and polymers. The hierarchical wrinkles with multiscale structures were prepared by sequential wrinkling, in which a sacrificial layer was used as the additional skin layer between sequences. For example, a hierarchical MoS 2 wrinkle exhibited highly enhanced catalytic behavior because of the superaerophobicity and effective surface area, which are related to topological effects. As the developed method can be adopted to a majority of thin films, it is thought to be a universal method for enhancing the physical properties of various materials.

Creating gradient wetting surfaces via electroless displacement of zinc-coated carbon steel by nickel ions

NASA Astrophysics Data System (ADS)

Xu, Chang; Liu, Huicong; Liang, Weitao; Zhu, Liqun; Li, Weiping; Chen, Haining

2018-03-01

Gradient wetting surfaces are getting increasing attention due to their wide application in multiple fields such as droplet movement and biosorption. However, the fabrication processes of full gradient wetting surfaces are still complex and costly. In present work, a facile and low-cost chemical immersion method was used to create a full gradient wetting surface. By controlling the displacement time in Ni2+ solution, the prepared surfaces perform hydrophilic to superhydrophilic. After being modified by stearic acid, the gradient hydrophilic surfaces convert into hydrophobic. The surface morphology, composition, and wetting behaviors of the as-prepared surfaces were systematically studied and discussed. The gradient wetting property could be attributed to the change in microroughness and surface energy. In addition, these surfaces also exhibited excellent self-cleaning and wax prevention properties. Furthermore, high stability and corrosion resistance were also found for these surfaces, which further highlight their promising practical applications in many fields.

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.

Preparation, Imaging, and Quantification of Bacterial Surface Motility Assays

PubMed Central

Morales-Soto, Nydia; Anyan, Morgen E.; Mattingly, Anne E.; Madukoma, Chinedu S.; Harvey, Cameron W.; Alber, Mark; Déziel, Eric; Kearns, Daniel B.; Shrout, Joshua D.

2015-01-01

Bacterial surface motility, such as swarming, is commonly examined in the laboratory using plate assays that necessitate specific concentrations of agar and sometimes inclusion of specific nutrients in the growth medium. The preparation of such explicit media and surface growth conditions serves to provide the favorable conditions that allow not just bacterial growth but coordinated motility of bacteria over these surfaces within thin liquid films. Reproducibility of swarm plate and other surface motility plate assays can be a major challenge. Especially for more “temperate swarmers” that exhibit motility only within agar ranges of 0.4%-0.8% (wt/vol), minor changes in protocol or laboratory environment can greatly influence swarm assay results. “Wettability”, or water content at the liquid-solid-air interface of these plate assays, is often a key variable to be controlled. An additional challenge in assessing swarming is how to quantify observed differences between any two (or more) experiments. Here we detail a versatile two-phase protocol to prepare and image swarm assays. We include guidelines to circumvent the challenges commonly associated with swarm assay media preparation and quantification of data from these assays. We specifically demonstrate our method using bacteria that express fluorescent or bioluminescent genetic reporters like green fluorescent protein (GFP), luciferase (lux operon), or cellular stains to enable time-lapse optical imaging. We further demonstrate the ability of our method to track competing swarming species in the same experiment. PMID:25938934

Effects of Sample Preparation on the Infrared Reflectance Spectra of Powders

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

Brauer, Carolyn S.; Johnson, Timothy J.; Myers, Tanya L.

2015-05-22

While reflectance spectroscopy is a useful tool in identifying molecular compounds, laboratory measurement of solid (particularly powder) samples often is confounded by sample preparation methods. For example, both the packing density and surface roughness can have an effect on the quantitative reflectance spectra of powdered samples. Recent efforts in our group have focused on developing standard methods for measuring reflectance spectra that accounts for sample preparation, as well as other factors such as particle size and provenance. In this work, the effect of preparation method on sample reflectivity was investigated by measuring the directional-hemispherical spectra of samples that were hand-packedmore » as well as pressed into pellets using an integrating sphere attached to a Fourier transform infrared spectrometer. The results show that the methods used to prepare the sample have a substantial effect on the measured reflectance spectra, as do other factors such as particle size.« less

Effects of sample preparation on the infrared reflectance spectra of powders

NASA Astrophysics Data System (ADS)

Brauer, Carolyn S.; Johnson, Timothy J.; Myers, Tanya L.; Su, Yin-Fong; Blake, Thomas A.; Forland, Brenda M.

2015-05-01

While reflectance spectroscopy is a useful tool for identifying molecular compounds, laboratory measurement of solid (particularly powder) samples often is confounded by sample preparation methods. For example, both the packing density and surface roughness can have an effect on the quantitative reflectance spectra of powdered samples. Recent efforts in our group have focused on developing standard methods for measuring reflectance spectra that accounts for sample preparation, as well as other factors such as particle size and provenance. In this work, the effect of preparation method on sample reflectivity was investigated by measuring the directional-hemispherical spectra of samples that were hand-loaded as well as pressed into pellets using an integrating sphere attached to a Fourier transform infrared spectrometer. The results show that the methods used to prepare the sample can have a substantial effect on the measured reflectance spectra, as do other factors such as particle size.

Synthesis and characterization of nanoporous silica aerogel beads using cheap industrial grade sodium silacte precursor

NASA Astrophysics Data System (ADS)

Khan, Tasneem M. A.; Khan, Asiya; Sarawade, Pradip B.

2018-05-01

We report a method to synthesize low-density transparent mesoporous silica aerogel beads by ambient pressure drying (APD). The beads were prepared by acid-base sol-gel polymerization of sodium silicate in via the ball dropping method (BDM). To minimize shrinkage during drying, wet silica beads were initially prepared; their surfaces were then modified using trimethylchlorosilane (TMCS) via simultaneous solvent exchange and surface modification. The specific surface area and cumulative pore volume of the silica aerogel beads increased with an increase in the %V of TMCS. Silica aerogel beads with low packing bed density, high surface area, and large cumulative pore volume was obtained when TMCS was used. Properties of the final product were examined by BET, and TG-DT analyses. The hydrophobic silica aerogel beads were thermally stable up to 350°C. We discuss our results and compare our findings for modified versus unmodified silica beads.

Cover-gas seal program. Test report - sodium dip-seal wetting study. [at 450/sup 0/F

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

Carnevali, R.

1977-10-20

This report documents the tests conducted to find a reliable surface preparation method of treating the CRBRP dip seal blade (SA508 Class 2 steel) to insure its sodium wettability at 450F or less. Two techniques were established which depressed the sodium wetting temperature of SA 508, Class 2 dip seal blade material to 375F. These techniques were depositing an approx. 60 x 10/sup -6/ inch layer of tin on the blade surface by a brush-on plating process, and, by cleaning the blade surface with ultrasonics while it is immersed in sodium. The tin plating technique is recommended as the initialmore » and primary surface preparation method and ultrasonics as a rewetting and backup technique. This work was conducted in support of the Sodium Dip Seal Feature Test, DRS 32.05.« less

Synthesis and immobilization of Ag(0) nanoparticles on diazonium modified electrodes: SECM and cyclic voltammetry studies of the modified interfaces.

PubMed

Noël, Jean-Marc; Zigah, Dodzi; Simonet, Jacques; Hapiot, Philippe

2010-05-18

A versatile method was used to prepare modified surfaces on which metallic silver nanoparticles are immobilized on an organic layer. The preparation method takes advantage, on one hand, of the activated reactivity of some alkyl halides with Ag-Pd alloys to produce metallic silver nanoparticles and, on the other hand, of the facile production of an anchoring polyphenyl acetate layer by the electrografting of substituted diazonium salts on carbon surfaces. Transport properties inside such modified layers were investigated by cyclic voltammetry, scanning electrochemical microscopy (SECM) in feedback mode, and conducting AFM imaging for characterizing the presence and nature of the conducting pathways. The modification of the blocking properties of the surface (or its conductivity) was found to vary to a large extent on the solvents used for surface examination (H(2)O, CH(2)Cl(2), and DMF).

Evaluation of Root Canal Preparation Using Rotary System and Hand Instruments Assessed by Micro-Computed Tomography

PubMed Central

Stavileci, Miranda; Hoxha, Veton; Görduysus, Ömer; Tatar, Ilkan; Laperre, Kjell; Hostens, Jeroen; Küçükkaya, Selen; Muhaxheri, Edmond

2015-01-01

Background Complete mechanical preparation of the root canal system is rarely achieved. Therefore, the purpose of this study was to evaluate and compare the root canal shaping efficacy of ProTaper rotary files and standard stainless steel K-files using micro-computed tomography. Material/Methods Sixty extracted upper second premolars were selected and divided into 2 groups of 30 teeth each. Before preparation, all samples were scanned by micro-computed tomography. Thirty teeth were prepared with the ProTaper system and the other 30 with stainless steel files. After preparation, the untouched surface and root canal straightening were evaluated with micro-computed tomography. The percentage of untouched root canal surface was calculated in the coronal, middle, and apical parts of the canal. We also calculated straightening of the canal after root canal preparation. Results from the 2 groups were statistically compared using the Minitab statistical package. Results ProTaper rotary files left less untouched root canal surface compared with manual preparation in coronal, middle, and apical sector (p<0.001). Similarly, there was a statistically significant difference in root canal straightening after preparation between the techniques (p<0.001). Conclusions Neither manual nor rotary techniques completely prepared the root canal, and both techniques caused slight straightening of the root canal. PMID:26092929

Preparation of stable silica surfaces for surface forces measurement

NASA Astrophysics Data System (ADS)

Ren, Huai-Yin; Mizukami, Masashi; Kurihara, Kazue

2017-09-01

A surface forces apparatus (SFA) measures the forces between two surfaces as a function of the surface separation distance. It is regarded as an essential tool for studying the interactions between two surfaces. However, sample surfaces used for the conventional SFA measurements have been mostly limited to thin (ca. 2-3 μm) micas, which are coated with silver layers (ca. 50 nm) on their back, due to the requirement of the distance determination by transmission mode optical interferometry called FECO (fringes of equal chromatic order). The FECO method has the advantage of determining the absolute distance, so it should be important to increase the availability of samples other than mica, which is chemically nonreactive and also requires significant efforts for cleaving. Recently, silica sheets have been occasionally used in place of mica, which increases the possibility of surface modification. However, in this case, the silver layer side of the sheet is glued on a cylindrical quartz disc using epoxy resin, which is not stable in organic solvents and can be easily swollen or dissolved. The preparation of substrates more stable under severe conditions, such as in organic solvents, is necessary for extending application of the measurement. In this study, we report an easy method for preparing stable silica layers of ca. 2 μm in thickness deposited on gold layers (41 nm)/silica discs by sputtering, then annealed to enhance the stability. The obtained silica layers were stable and showed no swelling in organic solvents such as ethanol and toluene.

Development of replicated optics for AXAF-1 XDA testing

NASA Technical Reports Server (NTRS)

Engelhaupt, Darell; Wilson, Michele; Martin, Greg

1995-01-01

Advanced optical systems for applications such as grazing incidence Wolter I x-ray mirror assemblies require extraordinary mirror surfaces in terms of fine finish and surface figure. The impeccable mirror surface is on the inside of the rotational mirror form. One practical method of producing devices with these requirements is to first fabricate an exterior surface for the optical device then replicate that surface to have the inverse component with lightweight characteristics. The replicated optic is not better than the master or mandrel from which it is made. This task identifies methods and materials for forming these extremely low roughness optical components. The objectives of this contract were to (1) prepare replication samples of electroless nickel coated aluminum, and determine process requirements for plating XDA test optic; (2) prepare and assemble plating equipment required to process a demonstration optic; (3) characterize mandrels, replicas and test samples for residual stress, surface contamination and surface roughness and figure using equipment at MSFC and; (4) provide technical expertise in establishing the processes, procedures, supplies and equipment needed to process the XDA test optics.

Simplified method for preparation of concentrated exoproteins produced by Staphylococcus aureus grown on surface of cellophane bag containing liquid medium.

PubMed

Ikigai, H; Seki, K; Nishihara, S; Masuda, S

1988-01-01

A simplified method for preparation of concentrated exoproteins including protein A and alpha-toxin produced by Staphylococcus aureus was successfully devised. The concentrated proteins were obtained by cultivating S. aureus organisms on the surface of a liquid medium-containing cellophane bag enclosed in a sterilized glass flask. With the same amount of medium, the total amount of proteins obtained by the method presented here was identical with that obtained by conventional liquid culture. The concentration of proteins obtained by the method, however, was high enough to observe their distinct bands stained on polyacrylamide gel electrophoresis. This method was considered quite useful not only for large-scale cultivation for the purification of staphylococcal proteins but also for small-scale study using the proteins. The precise description of the method was presented and its possible usefulness was discussed.

Fiber optic sensor and method for making

DOEpatents

Vartuli, James Scott; Bousman, Kenneth Sherwood; Deng, Kung-Li; McEvoy, Kevin Paul; Xia, Hua

2010-05-18

A fiber optic sensor including a fiber having a modified surface integral with the fiber wherein the modified surface includes an open pore network with optical agents dispersed within the open pores of the open pore network. Methods for preparing the fiber optic sensor are also provided. The fiber optic sensors can withstand high temperatures and harsh environments.

Polythioether Particles Armored with Modifiable Graphene Oxide Nanosheets.

PubMed

Rodier, Bradley J; Mosher, Eric P; Burton, Spencer T; Matthews, Rachael; Pentzer, Emily

2016-06-01

Facile and scalable fabrication methods are attractive to prepare materials for diverse applications. Herein, a method is presented to prepare cross-linked polymeric nanoparticles with graphene oxide (GO) nanosheets covalently attached to the surface. Alkene-modified GO serves as a surfactant in a miniemulsion polymerization, and the alkene functionalities of GO exposed to the oil-phase are incorporated into the polymer particle through thiol-ene reactions, leaving the unreacted alkene functional groups of the other face of GO available for further functionalization. The surface of GO-armored polymer particles is then modified with a small molecule fluorophore or carboxylic acid functional groups that bind to Fe2 O3 and TiO2 nanoparticles. This methodology provides a facile route to preparing complex hybrid composite materials. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

[Study on preparation and physicochemical properties of surface modified sintered bone].

PubMed

Li, Jingfeng; Zheng, Qixin; Guo, Xiaodong

2012-06-01

The aim of this study is to investigate a new method for preparing a biomimetic bone material-surface modified sintered bovine cancellous bone, and to improve its bioactivity as a tissue engineering bone. The prepared sintered bovine cancellous bones with the same size were randomly divided into two groups, immersing in 1 and 1. 5 times simulated body fluid (SBF), respectively. The three time periods of soak time were 7, 14, and 21 days. After sintered bone was dried, the surface morphology of sintered bone and surface mineralization composition were observed under scanning electron microscopy (SEM). By comparing the effect of surface modification of sintered bone materials, we chose the most ideal material and studied its pore size, the rate of the porosity, the compress and bend intensity. And then the material and the sintered bone material without surface modification were compared. The study indicated that sintered bone material immersed in SBF (1.5 times) for 14 days showed the best effect of surface modification, retaining the original physico-chemical properties of sintered bone.

Superhydrophobic Surfaces with Very Low Hysteresis Prepared by Aggregation of Silica Nanoparticles During In Situ Urea-Formaldehyde Polymerization.

PubMed

Diwan, Anubhav; Jensen, David S; Gupta, Vipul; Johnson, Brian I; Evans, Delwyn; Telford, Clive; Linford, Matthew R

2015-12-01

We present a new method for the preparation of superhydrophobic materials by in situ aggregation of silica nanoparticles on a surface during a urea-formaldehyde (UF) polymerization. This is a one-step process in which a two-tier topography is obtained. The polymerization is carried out for 30, 60, 120, 180, and 240 min on silicon shards. Silicon surfaces are sintered to remove the polymer. SEM and AFM show both an increase in the area covered by the nanoparticles and their aggregation with increasing polymerization time. Chemical vapor deposition of a fluorinated silane in the presence of a basic catalyst gives these surfaces hydrophobicity. Deposition of this low surface energy silane is confirmed by the F 1s signal in XPS. The surfaces show advancing water contact angles in excess of 160 degrees with very low hysteresis (< 7) after 120 min and 60 min polymerization times for 7 nm and 14 nm silica, respectively. Depositions are successfully demonstrated on glass substrates after they are primed with a UF polymer layer. Superhydrophobic surfaces can also be prepared on unsintered substrates.

Effect of Preparation Methods on Crystallization Behavior and Tensile Strength of Poly(vinylidene fluoride) Membranes

PubMed Central

Liu, Jie; Lu, Xiaolong; Wu, Chunrui

2013-01-01

Poly(vinylidene fluoride) (PVDF) membranes were prepared by non solvent induced phase separation (NIPS), melt spinning and the solution-cast method. The effect of preparation methods with different membrane formation mechanisms on crystallization behavior and tensile strength of PVDF membranes was investigated. Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) and X-ray diffraction (XRD) were employed to examine the crystal form of the surface layers and the overall membranes, respectively. Spherulite morphologies and thermal behavior of the membranes were studied by polarized light optical microscopy (PLO) and differential scanning calorimetry (DSC) separately. It was found that the crystallization behavior of PVDF membranes was closely related to the preparation methods. For membranes prepared by the NIPS method, the skin layers had a mixture of α and β phases, the overall membranes were predominantly α phase, and the total crystallinity was 60.0% with no spherulite. For melt spinning membranes, the surface layers also showed a mixture of α and β phases, the overall membranes were predominantly α phase. The total crystallinity was 48.7% with perfect spherulites. Whereas the crystallization behavior of solution-cast membranes was related to the evaporation temperature and the additive, when the evaporation temperature was 140 °C with a soluble additive in the dope solution, obvious spherulites appeared. The crystalline morphology of PVDF exerted a great influence on the tensile strength of the membranes, which was much higher with perfect spherulites. PMID:24957064

New immobilisation protocol for the template used in solid-phase synthesis of MIP nanoparticles

NASA Astrophysics Data System (ADS)

Chen, Lu; Muhammad, Turghun; Yakup, Burabiye; Piletsky, Sergey A.

2017-06-01

As a novel imprinting method, solid-phase synthesis has proven to be a promising approach to prepare polymer nanoparticles with specific recognition sites for a template molecule. In this method, imprinted polymer nanoparticles were synthesized using template immobilized on a solid support. Herein, preparation of immobilized templates on quartz chips through homogeneous route was reported as an efficient alternative strategy to heterogeneous one. The template molecule indole-3-butyric acid (IBA) was reacted with 3-aminopropyltriethoxysilane (APTES) to produce silylated template (IBA-APTES), and it was characterized by IR, 1H NMR and GC-MS. Then, the silylated template molecule was grafted onto the activated surfaces of quartz chip to prepare immobilized template (SiO2@IBA-APTES). The immobilization was confirmed by contact angle, XPS, UV and fluorescence measurement. Immobilization protocol has shown good reproducibility and stability of the immobilized template. MIP nanoparticles were prepared with high selectivity toward the molecule immobilized onto the solid surface. This provides a new approach for the development of molecularly imprinted nanoparticles.

The effect of precipitants on Ni-Al2O3 catalysts prepared by a co-precipitation method for internal reforming in molten carbonate fuel cells

PubMed Central

Jung, You-Shick; Yoon, Wang-Lai; Seo, Yong-Seog; Rhee, Young-Woo

2012-01-01

Ni-Al2O3 catalysts are prepared via the co-precipitation method using various precipitants: urea, Na2CO3, NaOH, K2CO3, KOH and NH4OH. The effects of the precipitants on the physicochemical properties and catalytic activities of the Ni-Al2O3 catalysts are investigated. The Ni50-urea catalyst displays the largest specific surface area and the highest pore volume. This catalyst also exhibits the highest Ni dispersion and the largest Ni surface area. Ni50-urea catalyst prepared with urea as precipitant and Ni50-K2CO3 catalyst prepared with K2CO3 as precipitant exhibit high pore volumes and good catalytic activities for methane steam reforming. The Ni50-urea catalyst exhibits the best physicochemical properties and shows good catalytic activity and a strong resistance to electrolyte contamination. PMID:22962548

Heterogeneity of activated carbons in adsorption of aniline from aqueous solutions

NASA Astrophysics Data System (ADS)

Podkościelny, P.; László, K.

2007-08-01

The heterogeneity of activated carbons (ACs) prepared from different precursors is investigated on the basis of adsorption isotherms of aniline from dilute aqueous solutions at various pH values. The APET carbon prepared from polyethyleneterephthalate (PET), as well as, commercial ACP carbon prepared from peat were used. Besides, to investigate the influence of carbon surface chemistry, the adsorption was studied on modified carbons based on ACP carbon. Its various oxygen surface groups were changed by both nitric acid and thermal treatments. The Dubinin-Astakhov (DA) equation and Langmuir-Freundlich (LF) one have been used to model the phenomenon of aniline adsorption from aqueous solutions on heterogeneous carbon surfaces. Adsorption-energy distribution (AED) functions have been calculated by using an algorithm based on a regularization method. Analysis of these functions for activated carbons studied provides important comparative information about their surface heterogeneity.

Shear bond strength of orthodontic metal brackets to aged composite using three primers

PubMed Central

Tayebi, Ali; Fallahzadeh, Farnoosh

2017-01-01

Background This study aimed to assess the effect of surface preparation with sandblasting and diamond bur along with the use of three primers on shear bond strength (SBS) of metal brackets to aged composite. Material and Methods In this in vitro, experimental study, 60 Filtek Z250 composite discs were fabricated (10×2mm), immersed in distilled water for 24 hours and subjected to 5000 thermal cycles. They were randomly divided into two groups (n=30) of sandblasting with aluminum oxide particles for 10 seconds and surface roughening with bur. Each group was randomly divided into three subgroups (n=10) for use of Transbond XT, Assure Plus and Composite Primer. Metal brackets were bonded and the samples were stored in distilled water for 24 hours followed by 2000 thermal cycles. The SBS of brackets was measured and the adhesive remnant index (ARI) score was calculated. The data were analyzed by one-way ANOVA, t-test and Chi square test. Results The difference in the mean SBS was not significant among the six subgroups. Conclusions All combinations of primers and surface preparation methods provided adequately high SBS between brackets and aged composite surfaces. Considering the ARI scores, surface roughening by bur is superior to sandblasting. Key words:Shear strength, composite resins, orthodontic brackets, aged composite, surface preparation. PMID:28638550

Nanopatterned articles produced using reconstructed block copolymer films

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

Russell, Thomas P.; Park, Soojin; Wang;, Jia-Yu

Nanopatterned surfaces are prepared by a method that includes forming a block copolymer film on a substrate, annealing and surface reconstructing the block copolymer film to create an array of cylindrical voids, depositing a metal on the surface-reconstructed block copolymer film, and heating the metal-coated block copolymer film to redistribute at least some of the metal into the cylindrical voids. When very thin metal layers and low heating temperatures are used, metal nanodots can be formed. When thicker metal layers and higher heating temperatures are used, the resulting metal structure includes nanoring-shaped voids. The nanopatterned surfaces can be transferred tomore » the underlying substrates via etching, or used to prepare nanodot- or nanoring-decorated substrate surfaces.« less

A Multipurpose Apparatus to Measure Viscosity and Surface Tension of Solutions: The Measurement of the Molecular Cross-Sectional Area of N-Proposal

ERIC Educational Resources Information Center

Xin Zhang; Shouxin Liu; Booxin Li; Na An; Fan Zhang

2004-01-01

A multipurpose apparatus that can be used to measure the viscosity of solution by the Ostwald method and the surface tension of solution by the drop-weight method or by the capillary-rise method is developed. The apparatus is convenient for in-situ preparation of solutions of different concentrations and avoids the error that frothing of the…

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.

Preparation and characterization of ultraflat Pt facets by atom-height-resolved differential optical microscopy

NASA Astrophysics Data System (ADS)

Azhagurajan, M.; Wen, R.; Kim, Y. G.; Itoh, T.; Sashikata, K.; Itaya, K.

2015-01-01

We recently demonstrated that improvements to our technique, laser confocal microscopy with differential interference microscopy (LCM-DIM), has rendered it fully capable of resolving monatomic steps with heights of ca. 0.25 nm on Au(111) and Pd(111) surfaces, even as low as 0.14 nm on Si(100), in aqueous solution. In this paper, we describe in detail a method to prepare and characterize, via atomic-layer-resolved LCM-DIM, ultraflat Pt(111) and Pt(100) facets over a wide surface area. The preparation of ultraflat surfaces is important in the characterization at the atomic scale of electrochemical processes under reaction conditions. To showcase the elegance of LCM-DIM, the anodic dissolution of Pt in aqueous HCl is briefly recounted.

Surface roughness measurement in the submicrometer range using laser scattering

NASA Astrophysics Data System (ADS)

Wang, S. H.; Quan, Chenggen; Tay, C. J.; Shang, H. M.

2000-06-01

A technique for measuring surface roughness in the submicrometer range is developed. The principle of the method is based on laser scattering from a rough surface. A telecentric optical setup that uses a laser diode as a light source is used to record the light field scattered from the surface of a rough object. The light intensity distribution of the scattered band, which is correlated to the surface roughness, is recorded by a linear photodiode array and analyzed using a single-chip microcomputer. Several sets of test surfaces prepared by different machining processes are measured and a method for the evaluation of surface roughness is proposed.

Non-Noble Metal Oxide Catalysts for Methane Catalytic Combustion: Sonochemical Synthesis and Characterisation

PubMed Central

Jędrzejczyk, Roman J.; Dziedzicka, Anna; Kuterasiński, Łukasz; Sitarz, Maciej

2017-01-01

The aim of this study was to obtain nanocrystalline mixed metal-oxide–ZrO2 catalysts via a sonochemically-induced preparation method. The effect of a stabiliser’s addition on the catalyst parameters was investigated by several characterisation methods including X-ray Diffraction (XRD), nitrogen adsorption, X-ray fluorescence (XRF), scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectrometer (EDS), transmission electron microscopy (TEM) and µRaman. The sonochemical preparation method allowed us to manufacture the catalysts with uniformly dispersed metal-oxide nanoparticles at the support surface. The catalytic activity was tested in a methane combustion reaction. The activity of the catalysts prepared by the sonochemical method was higher than that of the reference catalysts prepared by the incipient wetness method without ultrasonic irradiation. The cobalt and chromium mixed zirconia catalysts revealed their high activities, which are comparable with those presented in the literature. PMID:28686190

Black silicon with self-cleaning surface prepared by wetting processes

PubMed Central

2013-01-01

This paper reports on a simple method to prepare a hydrophobic surface on black silicon, which is fabricated by metal-assisted wet etching. To increase the reaction rate, the reaction device was placed in a heat collection-constant temperature type magnetic stirrer and set at room temperature. It was demonstrated that the micro- and nanoscale spikes on the black silicon made the surface become hydrophobic. As the reaction rate increases, the surface hydrophobicity becomes more outstanding and presents self-cleaning until the very end. The reflectance of the black silicon is drastically suppressed over a broad spectral range due to the unique geometry, which is effective for the enhancement of absorption. PMID:23941184

Microscopies optique et electronique du bioxyde d'uranium fritte (in French)

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

Porneuf, A.

1961-07-01

Methods of preparing surfaces of UO₂ by mechanical or electrolytic polishing, and of revealing the structure by anodic or chemical attack, by bombardment or by oxidation, are described and their respective limitations are analyzed. These various techniques were applied to the study of the influence of preparation conditions on the pore distribution, on the micro-profile of the external surfaces of compacts or of the internal surface of pores, on the surface structure of intergranular boundaries revealed by microfractography, etc. The sensitivity of the various quoted techniques allows patterns to be revealed which are similar to those revealed in metals andmore » which are undoubtedly related to the interaction of dislocations« less

PREPARATION OF REFRACTORY OXIDE CRYSTALS

DOEpatents

Grimes, W.R.; Shaffer, J.H.; Watson, G.M.

1962-11-13

A method is given for preparing uranium dioxide, thorium oxide, and beryllium oxide in the form of enlarged individual crystals. The surface of a fused alkali metal halide melt containing dissolved uranium, thorium, or beryllium values is contacted with a water-vapor-bearing inert gas stream at a rate of 5 to 10 cubic centimeters per minute per square centimeter of melt surface area. Growth of individual crystals is obtained by prolonged contact. Beryllium oxide-coated uranium dioxide crystals are prepared by disposing uranium dioxide crystals 5 to 20 microns in diameter in a beryllium-containing melt and contacting the melt with a water-vapor-bearing inert gas stream in the same manner. (AEC)

TREATMENT OF METALS PRIOR TO ELECTROPLATING

DOEpatents

Huddle, R.A.U.; Flint, O.

1958-05-20

The preparation of certain metal surfaces to receive electrodeposits is described. Surfaces of the metals are subjected to shot blasting by ferrous metal shot, and the surfaces then are given a coating of copper by displacement from a copper salt solution. The method applies to U, Zr, Ti, Ta, Ni, Mo, W, and V.

Preparation of transition metal nanoparticles and surfaces modified with (CO)polymers synthesized by RAFT

DOEpatents

McCormick, III., Charles L.; Lowe, Andrew B.; Sumerlin, Brent S.

2006-11-21

A new, facile, general one-phase method of generating thio-functionalized transition metal nanoparticles and surfaces modified by (co)polymers synthesized by the RAFT method is described. The method includes the stops of forming a (co)polymer in aqueous solution using the RAFT methodology, forming a colloidal transition metal precursor solution from an appropriate transition metal; adding the metal precursor solution or surface to the (co)polymer solution, adding a reducing agent into the solution to reduce the metal colloid in situ to produce the stabilized nanoparticles or surface, and isolating the stabilized nanoparticles or surface in a manner such that aggregation is minimized. The functionalized surfaces generated using these methods can further undergo planar surface modifications, such as functionalization with a variety of different chemical groups, expanding their utility and application.

Preparation of transition metal nanoparticles and surfaces modified with (co)polymers synthesized by RAFT

DOEpatents

McCormick, III, Charles L.; Lowe, Andrew B [Hattiesburg, MS; Sumerlin, Brent S [Pittsburgh, PA

2011-12-27

A new, facile, general one-phase method of generating thiol-functionalized transition metal nanoparticles and surfaces modified by (co)polymers synthesized by the RAFT method is described. The method includes the steps of forming a (co)polymer in aqueous solution using the RAFT methodology, forming a colloidal transition metal precursor solution from an appropriate transition metal; adding the metal precursor solution or surface to the (co)polymer solution, adding a reducing agent into the solution to reduce the metal colloid in situ to produce the stabilized nanoparticles or surface, and isolating the stabilized nanoparticles or surface in a manner such that aggregation is minimized. The functionalized surfaces generated using these methods can further undergo planar surface modifications, such as functionalization with a variety of different chemical groups, expanding their utility and application.

Construction of Bimetallic ZIF-Derived Co-Ni LDHs on the Surfaces of GO or CNTs with a Recyclable Method: Toward Reduced Toxicity of Gaseous Thermal Decomposition Products of Unsaturated Polyester Resin.

PubMed

Hou, Yanbei; Qiu, Shuilai; Hu, Yuan; Kundu, Chanchal Kumar; Gui, Zhou; Hu, Weizhao

2018-05-30

This work proposed an idea of recycling in preparing Co-Ni layered double hydroxide (LDH)-derived flame retardants. A novel and feasible method was developed to synthesize CO-Ni LDH-decorated graphene oxide (GO) and carbon nanotubes (CNTs), by sacrificing bimetal zeolitic imidazolate frameworks (ZIFs). Organic ligands that departed from ZIFs were recyclable and can be reused to synthesize ZIFs. ZIFs, as transitional objects, in situ synthesized on the surfaces of GO or CNTs directly suppressed the re-stacking of the carbides and facilitated the preparation of GO@LDHs and CNTs@LDHs. As-prepared hybrids catalytically reduced toxic CO yield during the thermal decomposition of unsaturated polyester resin (UPR). What is more, the release behaviors of aromatic compounds were also suppressed during the pyrolysis process of UPR composites. The addition of GO@LDHs and CNTs@LDHs obviously inhibited the heat release and smoke emission behaviors of the UPR matrix during combustion. Mechanical properties of the UPR matrix also improved by inclusion of the carbides derivatives. This work paved a feasible method to prepare well-dispersed carbides@Co-Ni LDH nanocomposites with a more environmentally friendly method.

Preparing Al-Mg Substrate for Thermal Spraying: Evaluation of Surface State After Different Pretreatments

NASA Astrophysics Data System (ADS)

Lukauskaitė, R.; Valiulis, A. V.; Černašėjus, O.; Škamat, J.; Rębiś, J. A.

2016-08-01

The article deals with the pretreatment technique for preparing the surface of aluminum alloy EN AW 5754 before thermal spray. The surface after different pretreatments, including degreasing with acetone, chemical etching with acidic and alkali solutions, grit-blasting, cathodic cleaning, and some combinations of these techniques, has been studied. The investigation of pre-treated surfaces covered the topographical study (using scanning electron microscopy, atomic force microscopy, and 3D profilometry), the chemical analysis by x-ray photoelectron spectroscopy, the evaluation of surface wettability (sessile drop method), and the assessment of surface free energy. Compared with all the techniques used in present work, the cathodic cleaning and its combination with grit-blasting provide the most preferable chemistry of the surface. Due to the absence of hydroxides at the surface and, possible, due to the diffusion of magnesium to the surface of substrate, the surface wettability and the surface free energy have been significantly improved. No direct correlation between the surface topography and the surface wettability has been established.

On-chip micropatterning of plastic (cylic olefin copolymer, COC) microfluidic channels for the fabrication of biomolecule microarrays using photografting methods.

PubMed

Pu, Qiaosheng; Oyesanya, Olufemi; Thompson, Bowlin; Liu, Shantang; Alvarez, Julio C

2007-01-30

This paper reports on the surface modification of plastic microfluidic channels to prepare different biomolecule micropatterns using ultraviolet (UV) photografting methods. The linkage chemistry is based upon UV photopolymerization of acryl monomers to generate thin films (0.01-6 microm) chemically linked to the organic backbone of the plastic surface. The commodity thermoplastic, cyclic olefin copolymer (COC) was selected to build microfluidic chips because of its significant UV transparency and easiness for microfabrication by molding techniques. Once the polyacrylic films were grafted on the COC surface using photomasks, micropatterns of proteins, DNA, and biotinlated conjugates were readily obtained by surface chemical reactions in one or two subsequent steps. The thickness of the photografted films can be tuned from several nanometers up to several micrometers, depending on the reaction conditions. The micropatterned films can be prepared inside the microfluidic channel (on-chip) or on open COC surfaces (off-chip) with densities of functional groups about 10(-7) mol/cm2. Characterization of these films was performed by attenuated-total-reflectance IR spectroscopy, fluorescence microscopy, profilometry, atomic force microscopy, and electrokinetic methods.

Activated Carbon Fibers "Thickly Overgrown" by Ag Nanohair Through Self-Assembly and Rapid Thermal Annealing

NASA Astrophysics Data System (ADS)

Yan, Xuefeng; Xu, Sijun; Wang, Qiang; Fan, Xuerong

2017-11-01

Anisotropic nanomaterial-modified carbon fibers attract increasing attention because of their superior properties over traditional ones. In this study, activated carbon fibers (ACFs) "thickly overgrown" by Ag nanohair were prepared through self-assembly and rapid thermal annealing. Viscose fibers with well-dispersed silver nanoparticles (AgNPs) on surfaces were first prepared through self-assembly of hyperbranched poly(amino-amine) (HBPAA)-capped AgNPs on viscose surfaces. HBPAA endowed the AgNP surfaces with negative charges and abundant amino groups, allowing AgNPs to monodispersively self-assemble to fiber surfaces. Ag nanohair-grown ACFs were prepared by sequential pre-oxidation and carbonization. Because the carbonization furnace was open-ended, ACFs are immediately transferrable to the outside of the furnace. Therefore, the Ag liquid adsorbed by ACF pores squeezed out to form Ag nanowires through thermal contraction. FESEM characterization indicated that Ag nanohairs stood on ACF surface and grew from ACF caps. XPS and XRD characterization showed that Ag successfully assembled to fiber surfaces and retained its metallic state even after high-temperature carbonization. TG analysis suggested that Ag nanohair-grown ACFs maintained their excellent thermal stabilities. Finally, the fabricated ACFs showed excellent and durable antibacterial activities, and the developed method may provide a potential strategy for preparing metal nanowire-grown ACFs.

Particles induced surface nanoroughness of titanium surface and its influence on adhesion of osteoblast-like MG-63 cells

NASA Astrophysics Data System (ADS)

Solař, P.; Kylián, O.; Marek, A.; Vandrovcová, M.; Bačáková, L.; Hanuš, J.; Vyskočil, J.; Slavínská, D.; Biederman, H.

2015-01-01

Titanium is one of the most common materials employed for production of implants, which is due to its good biocompatibility. However, the colonization of titanium surface by osteoblast cells may be influenced by its roughness and therefore precise control of roughness of titanium surface as well as identification of its optimal value for growth of cells is of high importance. In this study the nanorough titanium surfaces were prepared on polished disks of TiAlV by two step method of deposition. In the first step TiAlV were coated by nanoparticles generated by gas aggregation sources. Such prepared films of nanoparticles were subsequently covered with a titanium overlayer. Different values of surface roughness in the range 1-100 nm were achieved by variation of the size and number of the nanoparticles. Such prepared surfaces were subsequently used for investigation of influence of roughness of titanium surfaces on the adhesion of human osteoblast-like MG-63 cells. It was found out that 7 days after seeding the highest number of adhering cells was observed for samples with root-mean-square roughness of 30 nm.

Preparative free-flow electrophoresis as a method of fractionation of natural organic materials

USGS Publications Warehouse

Leenheer, J.A.; Malcolm, R.L.

1973-01-01

Preparative free-flow electrophoresis was found to be an efficient method of conducting large-scale fractionations of the natural organic polyelectrolytes occurring in many surface waters and soils. The method of free-flow electrophoresis obviates, the problem of adsorption upon a supporting medium and permits the use of high potential gradients and currents because of an efficient cooling system. Separations were monitored by determining organic carbon concentration with a dissolved carbon analyzer, and color was measured by absorbance at 400 nanometers. Organic materials from waters and soils were purified by filtration, hydrogen exchange, and dialysis and were concentrated by freeze drying or freeze concentration. In electrophoretic fractionations of natural organic materials typically found in surface waters and soils, color was found to increase with the charge of the fraction.

Highly sensitive surface-scanning detector for the direct bacterial detection using magnetoelastic (ME) biosensors

NASA Astrophysics Data System (ADS)

Liu, Yuzhe; Horikawa, Shin; Chen, I.-Hsuan; Du, Songtao; Wikle, Howard C.; Suh, Sang-Jin; Chin, Bryan A.

2017-05-01

This paper demonstrates a highly sensitive surface-scanning detector used for magnetoelastic (ME) biosensors for the detection of Salmonella on the surface of a polyethylene (PE) food preparation surface. The design and fabrication methods of the new planar spiral coil are introduced. Different concentrations of Salmonella were measured on the surface of a PE board. The efficacy of Salmonella capture and detection is discussed.

Preparation and Characterization of Ato Nanoparticles by Coprecipitation with Modified Drying Method

NASA Astrophysics Data System (ADS)

Liu, Shimin; Liang, Dongdong; Liu, Jindong; Jiang, Weiwei; Liu, Chaoqian; Ding, Wanyu; Wang, Hualin; Wang, Nan

Antimony-doped tin oxide (ATO) nanoparticles were prepared by coprecipitation by packing drying and traditional direct drying (for comparison) methods. The as-prepared ATO nanoparticles were characterized by TG, XRD, EDS, TEM, HRTEM, BET, bulk density and electrical resistivity measurements. Results indicated that the ATO nanoparticles obtained by coprecipitation with direct drying method featured hard-agglomerated morphology, high bulk density, low surface area and low electrical resistivity, probably due to the direct liquid evaporation during drying, the fast shrinkage of the precipitate, the poor removal efficiency of liquid molecules and the hard agglomerate formation after calcination. Very differently, the ATO product obtained by the packing and drying method featured free-agglomerated morphology, low bulk density, high surface area and high electrical resistivity ascribed probably to the formed vapor cyclone environment and liquid evaporation-resistance, avoiding fast liquid removal and improving the removal efficiency of liquid molecules. The intrinsic formation mechanism of ATO nanoparticles from different drying methods was illustrated based on the dehydration process of ATO precipitates. Additionally, the packing and drying time played key roles in determining the bulk density, morphology and electrical conductivity of ATO nanoparticles.

Optimization of preparation of antioxidative peptides from pumpkin seeds using response surface method.

PubMed

Fan, Sanhong; Hu, Yanan; Li, Chen; Liu, Yanrong

2014-01-01

Protein isolates of pumpkin (Cucurbita pepo L) seeds were hydrolyzed by acid protease to prepare antioxidative peptides. The hydrolysis conditions were optimized through Box-Behnken experimental design combined with response surface method (RSM). The second-order model, developed for the DPPH radical scavenging activity of pumpkin seed hydrolysates, showed good fit with the experiment data with a high value of coefficient of determination (0.9918). The optimal hydrolysis conditions were determined as follows: hydrolyzing temperature 50°C, pH 2.5, enzyme amount 6000 U/g, substrate concentration 0.05 g/ml and hydrolyzing time 5 h. Under the above conditions, the scavenging activity of DPPH radical was as high as 92.82%.

Biomolecular hybrid material and process for preparing same and uses for same

DOEpatents

Kim, Jungbae [Richland, WA

2010-11-23

Disclosed is a composition and method for fabricating novel hybrid materials comprised of, e.g., carbon nanotubes (CNTs) and crosslinked enzyme clusters (CECs). In one method, enzyme-CNT hybrids are prepared by precipitation of enzymes which are subsequently crosslinked, yielding crosslinked enzyme clusters (CECs) on the surface of the CNTs. The CEC-enzyme-CNT hybrids exhibit high activity per unit area or mass as well as improved enzyme stability and longevity over hybrid materials known in the art. The CECs in the disclosed materials permit multilayer biocatalytic coatings to be applied to surfaces providing hybrid materials suitable for use in, e.g., biocatalytic applications and devices as described herein.

Fabrication of superhydrophobic copper surface on various substrates for roll-off, self-cleaning, and water/oil separation.

PubMed

Sasmal, Anup Kumar; Mondal, Chanchal; Sinha, Arun Kumar; Gauri, Samiran Sona; Pal, Jaya; Aditya, Teresa; Ganguly, Mainak; Dey, Satyahari; Pal, Tarasankar

2014-12-24

Superhydrophobic surfaces prevent percolation of water droplets and thus render roll-off, self-cleaning, corrosion protection, etc., which find day-to-day and industrial applications. In this work, we developed a facile, cost-effective, and free-standing method for direct fabrication of copper nanoparticles to engender superhydrophobicity for various flat and irregular surfaces such as glass, transparency sheet (plastic), cotton wool, textile, and silicon substrates. The fabrication of as-prepared superhydrophobic surfaces was accomplished using a simple chemical reduction of copper acetate by hydrazine hydrate at room temperature. The surface morphological studies demonstrate that the as-prepared surfaces are rough and display superhydrophobic character on wetting due to generation of air pockets (The Cassie-Baxter state). Because of the low adhesion of water droplets on the as-prepared surfaces, the surfaces exhibited not only high water contact angle (164 ± 2°, 5 μL droplets) but also superb roll-off and self-cleaning properties. Superhydrophobic copper nanoparticle coated glass surface uniquely withstands water (10 min), mild alkali (5 min in saturated aqueous NaHCO3 of pH ≈ 9), acids (10 s in dilute HNO3, H2SO4 of pH ≈ 5) and thiol (10 s in neat 1-octanethiol) at room temperature (25-35 °C). Again as-prepared surface (cotton wool) was also found to be very effective for water-kerosene separation due to its superhydrophobic and oleophilic character. Additionally, the superhydrophobic copper nanoparticle (deposited on glass surface) was found to exhibit antibacterial activity against both Gram-negative and Gram-positive bacteria.

Surface functionalized mesoporous material and method of making same

DOEpatents

Feng, Xiangdong [West Richland, WA; Liu, Jun [West Richland, WA; Fryxell, Glen E [Kennewick, WA

2001-12-04

According to the present invention, an organized assembly of functional molecules with specific interfacial functionality (functional group(s)) is attached to available surfaces including within mesopores of a mesoporous material. The method of the present invention avoids the standard base soak that would digest the walls between the mesopores by boiling the mesoporous material in water for surface preparation then removing all but one or two layers of water molecules on the internal surface of a pore. Suitable functional molecule precursor is then applied to permeate the hydrated pores and the precursor then undergoes condensation to form the functional molecules on the interior surface(s) of the pore(s).

Delay in the Freezing of Supercooled Water Drops on Superhydrophobic Surfaces of Silicone Rubber at Negative Temperatures

NASA Astrophysics Data System (ADS)

Bezdomnikov, A. A.; Emel'yanenko, A. M.; Emel'yanenko, K. A.; Boinovich, L. B.

2018-01-01

A method is proposed for fabricating textured superhydrophobic surfaces of silicone rubber with mechanical resistance toward liquid or freezing aqueous solutions. The anti-icing characteristics of silicone rubber samples that differ in the wetting characteristics and mechanical stability of their micro- and nanotextures are derived by analyzing the delays in the freezing of supercooled sessile water drops deposited on the sample surface. The longest delay in freezings are observed for sessile water drops on superhydrophobic surfaces prepared by laser texturing with subsequent application of a layer of a hydrophobic agent to consolidate the textural elements. Delay in freezings can be as long as tens of hours on such surfaces at T = -18°C. The prepared superhydrophobic surfaces exhibit greater anti-icing ability with respect to aqueous salt solutions than to deionized water.

Process of preparing metal parts to be heated by means of infrared radiance

DOEpatents

Mayer, Howard Robinson [Cincinnati, OH; Blue, Craig A [Knoxville, TN

2009-06-09

A method for preparing metal for heating by infrared radiance to enable uniform and consistent heating. The surface of one or more metal parts, such as aluminum or aluminum alloy parts, is treated to alter the surface finish to affect the reflectivity of the surface. The surface reflectivity is evaluated, such as by taking measurements at one or more points on the surface, to determine if a desired reflectivity has been achieved. The treating and measuring are performed until the measuring indicates that the desired reflectivity has been achieved. Once the treating has altered the surface finish to achieve the desired reflectivity, the metal part may then be exposed to infrared radiance to heat the metal part to a desired temperature, and that heating will be substantially consistent throughout by virtue of the desired reflectivity.

Corrosion resistance of premodeled wires made of stainless steel used for heart electrotherapy leaders

NASA Astrophysics Data System (ADS)

Przondziono, J.; Walke, W.; Młynarski, R.; Szatka, W.

2012-05-01

The purpose of the study is to evaluate resistance to electrochemical corrosion of wire made of X10CrNi18-8 stainless steel designed for use in cardiology treatment. The influence of strain formed in the premodeling process and methods of wire surface preparation to corrosive resistance in artificial plasma solution were analysed. Wire corrosion tests were carried out in the solution of artificial plasma. Resistance to electrochemical corrosion was evaluated on the ground of recorded curves of anodic polarization by means of potentiodynamic method. Potentiodynamic tests carried out enabled to determine how the resistance to pitting corrosion of wire changes, depending on strain formed in the premodeling process as well as on the method of wire surface preparation. For evaluation of phenomena occurring on the surface of tested steel, electrochemical impedance spectroscopy (EIS) was applied. Deterioration of corrosive properties of wire along with the increase in the formed strain hardening was observed.

Joint surface modeling with thin-plate splines.

PubMed

Boyd, S K; Ronsky, J L; Lichti, D D; Salkauskas, K; Chapman, M A; Salkauskas, D

1999-10-01

Mathematical joint surface models based on experimentally determined data points can be used to investigate joint characteristics such as curvature, congruency, cartilage thickness, joint contact areas, as well as to provide geometric information well suited for finite element analysis. Commonly, surface modeling methods are based on B-splines, which involve tensor products. These methods have had success; however, they are limited due to the complex organizational aspect of working with surface patches, and modeling unordered, scattered experimental data points. An alternative method for mathematical joint surface modeling is presented based on the thin-plate spline (TPS). It has the advantage that it does not involve surface patches, and can model scattered data points without experimental data preparation. An analytical surface was developed and modeled with the TPS to quantify its interpolating and smoothing characteristics. Some limitations of the TPS include discontinuity of curvature at exactly the experimental surface data points, and numerical problems dealing with data sets in excess of 2000 points. However, suggestions for overcoming these limitations are presented. Testing the TPS with real experimental data, the patellofemoral joint of a cat was measured with multistation digital photogrammetry and modeled using the TPS to determine cartilage thicknesses and surface curvature. The cartilage thickness distribution ranged between 100 to 550 microns on the patella, and 100 to 300 microns on the femur. It was found that the TPS was an effective tool for modeling joint surfaces because no preparation of the experimental data points was necessary, and the resulting unique function representing the entire surface does not involve surface patches. A detailed algorithm is presented for implementation of the TPS.

A Facile All-Solution-Processed Surface with High Water Contact Angle and High Water Adhesive Force.

PubMed

Chen, Mei; Hu, Wei; Liang, Xiao; Zou, Cheng; Li, Fasheng; Zhang, Lanying; Chen, Feiwu; Yang, Huai

2017-07-12

A series of sticky superhydrophobicity surfaces with high water contact angle and high water adhesive force is facilely prepared via an all-solution-processed method based on polymerization-induced phase separation between liquid crystals (LCs) and epoxy resin, which produces layers of epoxy microspheres (EMSs) with nanofolds on the surface of a substrate. The morphologies and size distributions of EMSs are confirmed by scanning electron microscopy. Results reveal that the obtained EMS coated-surface exhibits high apparent contact angle of 152.0° and high water adhesive force up to 117.6 μN. By varying the composition of the sample or preparing conditions, the sizes of the produced EMSs can be artificially regulated and, thus, control the wetting properties and water adhesive behaviors. Also, the sticky superhydrophobic surface exhibits excellent chemical stability, as well as long-term durability. Water droplet transportation experiments further prove that the as-made surface can be effectively used as a mechanical hand for water transportation applications. Based on this, it is believed that the simple method proposed in this paper will pave a new way for producing a sticky superhydrophobic surface and obtain a wide range of use.

Engineering surface states of carbon dots to achieve controllable luminescence for solid-luminescent composites and sensitive Be2+ detection

PubMed Central

Li, Xiaoming; Zhang, Shengli; Kulinich, Sergei A.; Liu, Yanli; Zeng, Haibo

2014-01-01

Luminescent carbon dots (L-CDs) with high quantum yield value (44.7%) and controllable emission wavelengths were prepared via a facile hydrothermal method. Importantly, the surface states of the materials could be engineered so that their photoluminescence was either excitation-dependent or distinctly independent. This was achieved by changing the density of amino-groups on the L-CD surface. The above materials were successfully used to prepare multicolor L-CDs/polymer composites, which exhibited blue, green, and even white luminescence. In addition, the excellent excitation-independent luminescence of L-CDs prepared at low temperature was tested for detecting various metal ions. As an example, the detection limit of toxic Be2+ ions, tested for the first time, was as low as 23 μM.

Preparation and Structural Studies on Hybrid Core-Shell Nanoparticles Consisting of Silica Core and Conjugated Block Copolymer Shell Prepared by Surface-Initiated Polymerization

NASA Astrophysics Data System (ADS)

Chatterjee, Sourav; Karam, Tony; Rosu, Cornelia; Li, Xin; Do, Changwoo; Youm, Sang Gil; Haber, Louis; Russo, Paul; Nesterov, Evgueni

Controlled Kumada catalyst-transfer polymerization occurring by chain-growth mechanism was developed for the synthesis of conjugated polymers and block copolymers from the surface of inorganic substrates such as silica nanoparticles. Although synthesis of conjugated polymers via Kumada polymerization became an established method for solution polymerization, carrying out the same reaction in heterogeneous conditions to form monodisperse polymer chains still remains a challenge. We developed and described a simple and efficient approach to the preparation of surface-immobilized layer of catalytic Ni(II) initiator, and demonstrated using it to prepare polymers and block copolymers on silica nanoparticle. The structure of the resulting hybrid nanostructures was thoroughly studied using small-angle neutron and X-ray scattering, thermal analysis, and optical spectroscopy. The photoexcitation energy transfer processes in the conjugated polymer shell were studied via steady-state and time resolved transient absorption spectroscopy. This study uncovered important details of the energy transfer, which will be discussed in this presentation.

Development of second generation gold-supported palladium material with low-leaching and recyclable characteristics in aromatic amination.

PubMed

Al-Amin, Mohammad; Arai, Satoshi; Hoshiya, Naoyoki; Honma, Tetsuo; Tamenori, Yusuke; Sato, Takatoshi; Yokoyama, Mami; Ishii, Akira; Takeuchi, Masashi; Maruko, Tomohiro; Shuto, Satoshi; Arisawa, Mitsuhiro

2013-08-02

An improved process for the preparation of sulfur-modified gold-supported palladium material [SAPd, second generation] is presented. The developed preparation method is safer and generates less heat (aqueous Na2S2O8 and H2SO4) for sulfur fixation on a gold surface, and it is superior to the previous method of preparing SAPd (first generation), which requires the use of the more heat-generating and dangerous piranha solution (concentrated H2SO4 and 35% H2O2) in the sulfur fixation step. This safer and improved preparation method is particularly important for the mass production of SAPd (second generation) for which the catalytic activity was examined in ligand-free Buchwald-Hartwig cross-coupling reactions. The catalytic activities were the same between the first and second generation SAPds in aromatic aminations, but the lower palladium leaching properties and safer preparative method of second generation SAPd are a significant improvement over the first generation SAPd.

[Oxygen plasma-vulcanized deformable polydimethylsiloxane sheet culture substrates].

PubMed

Zhang, Yiyi; Tao, Zulai

2003-06-01

A method of preparing deformable polydimethylsiloxane sheet culture substrates by oxygen plasma vulcanization was developed. As compared with the traditional heating vulcanization method, the substrates prepared in this way have hydrophilic surfaces, the adhesion and spreading of cells both occur quickly, and the wrinkling deformation of substrates develops quickly, too. In addition, the changes of wrinkles during treatment of cytochalasin D were observed, and the result shows that this technique has high temporal resolution.

Programmable Liquid Crystal Elastomers Prepared by Thiol-Ene Photopolymerization (Postprint)

DTIC Science & Technology

2015-08-17

defect forms a 2D wrinkling pattern that leads to an areal contraction (Figure 4c,d). Both of these films return to a largely flat state on cooling...photopolymerization. ■ MATERIALS AND METHODS RM82 (1,4-bis-[4-(6-acryloyloxyhexyloxy)benzoyloxy]-2-methylben- zene) was purchased from Synthon Chemicals. 1,2...noted. Liquid crystal cells were prepared using methods described elsewhere.10 Briefly for cells patterned using rubbed surfaces, Elvamide was

Sol-Gel Synthesis of Non-Silica Monolithic Materials

PubMed Central

Gaweł, Bartłomiej; Gaweł, Kamila; Øye, Gisle

2010-01-01

Monolithic materials have become very popular because of various applications, especially within chromatography and catalysis. Large surface areas and multimodal porosities are great advantages for these applications. New sol-gel preparation methods utilizing phase separation or nanocasting have opened the possibility for preparing materials of other oxides than silica. In this review, we present different synthesis methods for inorganic, non-silica monolithic materials. Some examples of application of the materials are also included.

Microleakage in conservative cavities varying the preparation method and surface treatment

PubMed Central

ATOUI, Juliana Abdallah; CHINELATTI, Michelle Alexandra; PALMA-DIBB, Regina Guenka; CORONA, Silmara Aparecida Milori

2010-01-01

Objective To assess microleakage in conservative class V cavities prepared with aluminum-oxide air abrasion or turbine and restored with self-etching or etch-and-rinse adhesive systems. Material and Methods Forty premolars were randomly assigned to 4 groups (I and II: air abrasion; III and IV: turbine) and class V cavities were prepared on the buccal surfaces. Conditioning approaches were: groups I/III - 37% phosphoric acid; groups II/IV -self-priming etchant (Tyrian-SPe). Cavities were restored with One Step Plus/Filtek Z250. After finishing, specimens were thermocycled, immersed in 50% silver nitrate, and serially sectioned. Microleakage at the occlusal and cervical interfaces was measured in mm and calculated by a software. Data were subjected to ANOVA and Tukey’s test (α=0.05). Results Forty premolars were randomly assigned to 4 groups (I and II: air abrasion; III and IV: turbine) and class V cavities were prepared on the buccal surfaces. Conditioning approaches were: groups I/III - 37% phosphoric acid; groups II/IV -self-priming etchant (Tyrian-SPe). Cavities were restored with One Step Plus/Filtek Z250. After finishing, specimens were thermocycled, immersed in 50% silver nitrate, and serially sectioned. Microleakage at the occlusal and cervical interfaces was measured in mm and calculated by a software. Data were subjected to ANOVA and Tukey’s test (α=0.05). Conclusion Marginal seal of cavities prepared with aluminum-oxide air abrasion was different from that of conventionally prepared cavities, and the etch-and-rinse system promoted higher marginal seal at both enamel and dentin margins. PMID:20835580

Surface-Directed Synthesis of Erbium-Doped Yttrium Oxide Nanoparticles within Organosilane Zeptoliter Containers

PubMed Central

2015-01-01

We introduce an approach to synthesize rare earth oxide nanoparticles using high temperature without aggregation of the nanoparticles. The dispersity of the nanoparticles is controlled at the nanoscale by using small organosilane molds as reaction containers. Zeptoliter reaction vessels prepared from organosilane self-assembled monolayers (SAMs) were used for the surface-directed synthesis of rare earth oxide (REO) nanoparticles. Nanopores of octadecyltrichlorosilane were prepared on Si(111) using particle lithography with immersion steps. The nanopores were filled with a precursor solution of erbium and yttrium salts to confine the crystallization step to occur within individual zeptoliter-sized organosilane reaction vessels. Areas between the nanopores were separated by a matrix film of octadecyltrichlorosilane. With heating, the organosilane template was removed by calcination to generate a surface array of erbium-doped yttria nanoparticles. Nanoparticles synthesized by the surface-directed approach retain the periodic arrangement of the nanopores formed from mesoparticle masks. While bulk rare earth oxides can be readily prepared by solid state methods at high temperature (>900 °C), approaches for preparing REO nanoparticles are limited. Conventional wet chemistry methods are limited to low temperatures according to the boiling points of the solvents used for synthesis. To achieve crystallinity of REO nanoparticles requires steps for high-temperature processing of samples, which can cause self-aggregation and dispersity in sample diameters. The facile steps for particle lithography address the problems of aggregation and the requirement for high-temperature synthesis. PMID:25163977

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.

Synthesis of silica aerogel monoliths with controlled specific surface areas and pore sizes

NASA Astrophysics Data System (ADS)

Gao, Bingying; Lu, Shaoxiang; Kalulu, Mulenga; Oderinde, Olayinka; Ren, Lili

2017-07-01

To replace traditional preparation methods of silica aerogels, a small-molecule 1,2-epoxypropane (PO) has been introduced into the preparation process instead of using ammonia as the cross-linking agent, thus generating a lightweight, high porosity, and large surface area silica aerogel monolithic. We put forward a simple solution route for the chemical synthesis of silica aerogels, which was characterized by scanning electron microscopy (SEM), TEM, XRD, FTIR, thermogravimetric analysis (TGA) and the Brunauer-Emmett-Teller (BET) method In this paper, the effect of the amount of PO on the microstructure of silica aerogels is discussed. The BET surface areas and pore sizes of the resulting silica aerogels can be freely adjusted by changing the amount of PO, which will be helpful in promoting the development of silica aerogels to fabricate other porous materials with similar requirements. We also adopted a new organic solvent sublimation drying (OSSD) method to replace traditional expensive and dangerous drying methods such as critical point drying and freeze drying. This simple approach is easy to operate and has good repeatability, which will further facilitate actual applications of silica aerogels.

Enhancement of the electrooxidation of ethanol on Pt-Sn-P/C catalysts prepared by chemical deposition process

NASA Astrophysics Data System (ADS)

Xue, Xinzhong; Ge, Junjie; Tian, Tian; Liu, Changpeng; Xing, Wei; Lu, Tianhong

In this paper, five Pt 3Sn 1/C catalysts have been prepared using three different methods. It was found that phosphorus deposited on the surface of carbon with Pt and Sn when sodium hypophosphite was used as reducing agent by optimization of synthetic conditions such as pH in the synthetic solution and temperature. The deposition of phosphorus should be effective on the size reduction and markedly reduces PtSn nanoparticle size, and raise electrochemical active surface (EAS) area of catalyst and improve the catalytic performance. TEM images show PtSnP nanoparticles are highly dispersed on the carbon surface with average diameters of 2 nm. The optimum composition is Pt 3Sn 1P 2/C (note PtSn/C-3) catalyst in my work. With this composition, it shows very high activity for the electrooxidation of ethanol and exhibit enhanced performance compared with other two Pt 3Sn 1/C catalysts that prepared using ethylene glycol reduction method (note PtSn/C-EG) and borohydride reduction method (note PtSn/-B). The maximum power densities of direct ethanol fuel cell (DEFC) were 61 mW cm -2 that is 150 and 170% higher than that of the PtSn/C-EG and PtSn/C-B catalyst.

Mechanically durable carbon nanotube-composite hierarchical structures with superhydrophobicity, self-cleaning, and low-drag.

PubMed

Jung, Yong Chae; Bhushan, Bharat

2009-12-22

Superhydrophobic surfaces with high contact angle and low contact angle hysteresis exhibit a self-cleaning effect and low drag for fluid flow. The lotus (Nelumbo nucifera) leaf is one of the examples found in nature for superhydrophobic surfaces. For the development of superhydrophobic surfaces, which is important for various applications such as glass windows, solar panels, and microchannels, materials and fabrication methods need to be explored to provide mechanically durable surfaces. It is necessary to perform durability studies on these surfaces. Carbon nanotube (CNT), composite structures which would lead to superhydrophobicity, self-cleaning, and low-drag, were prepared using a spray method. As a benchmark, structured surfaces with lotus wax were also prepared to compare with the durability of CNT composite structures. To compare the durability of the various fabricated surfaces, waterfall/jet tests were conducted to determine the loss of superhydrophobicity by changing the flow time and pressure conditions. Wear and friction studies were also performed using an atomic force microscope (AFM) and a ball-on-flat tribometer. The changes in the morphology of the structured surfaces were examined by AFM and optical imaging. We find that superhydrophobic CNT composite structures showed good mechanical durability, superior to the structured surfaces with lotus wax, and may be suitable for real world applications.

An in vitro study evaluating the effect of ferrule design on the fracture resistance of endodontically treated mandibular premolars after simulated crown lengthening or forced eruption methods.

PubMed

Meng, Qingfei; Ma, Qian; Wang, Tianda; Chen, Yaming

2018-05-10

The purpose of this study was to evaluate the effect of ferrule design on the fracture resistance of endodontically treated mandibular first premolars after simulated crown lengthening and orthodontic forced eruption methods restored with a fiber post-and-core system. Forty extracted and endodontically treated mandibular first premolars were decoronated to create lingual-to-buccal oblique residual root models, with a 2.0 mm height of the lingual dentine wall coronal to the cemento-enamel junction, and the height of buccal surface at the cemento-enamel junction. The roots were divided randomly into five equal groups. The control group had undergone incomplete ferrule preparation in the cervical root, with 0.0 mm buccal and 2.0 mm lingual ferrule lengths (Group F0). Simulated surgical crown lengthening method provided ferrule preparation of 1.0 mm (Group CL/F1) and 2.0 mm (Group CL/F2) on the buccal surface, with ferrule lengths of 3.0 mm and 4.0 mm on the lingual surface, respectively. Simulated orthodontic forced eruption method provided ferrule preparation of 1.0 mm (Group OE/F1) and 2.0 mm (Group OE/F2) on the buccal surface and ferrule lengths of 3.0 mm and 4.0 mm on the lingual surface, respectively. After restoration with a glass fiber post-and-core system and a cast Co-Cr alloy crown, each specimen was embedded in an acrylic resin block to a height on the root 2.0 mm from the apical surface of the crown margin and loaded to fracture at a 135° angle to its long axis in a universal testing machine. Data were analyzed statistically using two-way ANOVA with Tukey HSD tests and Fisher's test, with α = 0.05. Mean fracture loads (kN) for groups F0, CL/F1, CL/F2, OE/F1 and OE/F2 were as follows: 1.01 (S.D. = 0.26), 0.91 (0.29), 0.73 (0.19), 0.96 (0.25) and 0.76 (0.20), respectively. Two-way ANOVA revealed significant differences for the effect of ferrule lengths (P = 0.012) but no differences for the effect of cervical treatment methods (P = 0.699). The teeth with no buccal ferrule preparation in control group F0 had the highest fracture resistance. In contrast, the mean fracture loads for group CL/F2 with a 2.0-mm buccal and 4.0-mm lingual ferrule created by simulated crown lengthening method were lowest (P = 0.036). Increased apically complete ferrule preparation resulted in decreased fracture resistance of endodontically treated mandibular first premolars, regardless of whether surgical crown lengthening or orthodontic forced eruption methods been used.

Kitchen practices used in handling broiler chickens and survival of Campylobacter spp. on cutting surfaces in Kampala, Uganda.

PubMed

Wanyenya, Irene; Muyanja, Charles; Nasinyama, George William

2004-09-01

Cross-contamination during food preparation has been identified as an important factor associated with foodborne illnesses. Handling practices used during preparation of broiler chickens in 31 fast-food restaurants and 86 semisettled street stands (street vendors) were assessed by use of a standard checklist. These establishments used wood, plastic, or metal cutting surfaces during the preparation of broiler chickens. The survival of Campylobacter spp. on kitchen cutting surfaces was determined by inoculating approximately 10(6) CFU of Campylobacter jejuni onto sterile plastic, wooden, and metal cutting boards. The concentrations of the organisms were then assessed in triplicate on each type of cutting board over a 3-h period using standard microbiological methods for thermophilic Campylobacter spp. In 87% of food establishments, the same work area was used for preparation of raw and cooked chicken, and in 68% of these establishments the same cutting boards were used for raw and cooked chicken. None of the establishments applied disinfectants or sanitizers when washing contact surfaces. Campylobacter spp. survived on wooden and plastic but not on metal cutting boards after 3 h of exposure. The handling practices in food preparation areas, therefore, provide an opportunity for cross-contamination of Campylobacter spp. to ready-to-eat foods.

Preparation and characterization of activated carbon from acorn shell by physical activation with H2O-CO2 in two-step pretreatment.

PubMed

Şahin, Ömer; Saka, Cafer

2013-05-01

Activated carbons have been prepared by physical activation with H2O-CO2 in two-step pre-treatment including ZnCl2-HCl from acorn shell at 850 °C. The active carbons were characterized by N2 adsorption at 77 K. Adsorption capacity was demonstrated by the iodine numbers. The surface chemical characteristics of activated carbons were determined by FTIR spectroscopic method. The microstructure of the activated carbons prepared was examined by scanning electron microscopy. The maximum BET surface area of the obtained activated carbon was found to be around 1779 m(2)/g. Copyright © 2013 Elsevier Ltd. All rights reserved.

Clinical Evaluation of Different Pre-impression Preparation Procedures of Dental Arch.

PubMed

Arora, Nitin; Arora, Monika; Gupta, Naveen; Agarwal, Manisha; Verma, Rohit; Rathod, Pankaj

2015-07-01

Bubbles and voids on the occlusal surface impede the actual intercuspation and pre-impression preparation aims to reduce the incidence of air bubbles and voids as well as influences the quality of occlusal reproduction and actual clinical intercuspation in the articulator. The study was undertaken to determine the influence of different pre-impression preparation procedures of antagonistic dental arch on the quality of the occlusal reproduction of the teeth in irreversible hydrocolloid impressions and to determine most reliable pre-impression preparation method to reduce the incidence of air bubbles. A total of 20 subjects were selected having full complement of mandibular teeth from second molar to second molar with well demarcated cusp height. 200 impressions were made with irreversible hydrocolloid material. The impressions were divided into five groups of 40 impressions each and each group had one specific type of pre-impression preparation. All the impressions were poured in die stone. A stereomicroscope with graduated eyepiece was used to count the number of bubbles on the occlusal surface of premolars and molars. The mean and standard deviations were calculated for each group. Mann-Whitney U-test was applied to find the significant difference between different groups. Least bubbles were found in the group in which oral cavity was dried by saliva ejector and fluid hydrocolloid was finger painted onto the occlusal surfaces immediately before the placement of impression tray in the mouth. It was found that finger painting the tooth surfaces with fluid hydrocolloid immediately before the placement of loaded impression tray in the mouth was the most reliable method. The oral cavity can be cleared more easily of excess saliva by vacuum suction rather than by use of an astringent solution.

The simple preparation of birnessite-type manganese oxide with flower-like microsphere morphology and its remarkable capacity retention

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

Zhu, Gang; Deng, Lingjuan; Wang, Jianfang

Graphical abstract: Flower-like birnessite-type manganese oxide microspheres with large specific surface area and excellent electrochemical properties have been prepared by a facile hydrothermal method. Highlights: ► Birnessite-type manganese oxide with flower-like microsphere morphology and large specific surface area. ► A facile low-temperature hydrothermal method. ► Novel flower-like microsphere consists of the thin nano-platelets. ► Birnessite-type manganese oxide exhibits an ideal capacitive behavior and excellent cycling stability. -- Abstract: Birnessite-type manganese oxide with flower-like microsphere morphology and large specific surface area has been prepared by hydrothermal treating a mixture solution of KMnO{sub 4} and (NH{sub 4}){sub 2}SO{sub 4} at 90 °Cmore » for 24 h. The obtained material is characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy and N{sub 2} adsorption–desorption. Results indicate that the birnessite-type manganese oxide shows novel flower-like microsphere morphology and a specific surface area of 280 m{sup 2} g{sup −1}, and the flower-like microsphere consists of the thin nano-platelets. Electrochemical characterization indicates that the prepared material exhibits an ideal capacitive behavior with a capacitance value of 278 F g{sup −1} in 1 mol L{sup −1} Na{sub 2}SO{sub 4} aqueous solution at a scan rate of 5 mV s{sup −1}. Moreover, the prepared manganese oxide electrode shows excellent cycle stability, and the specific capacitance can maintain 98.6% of the initial one after 5000 cycles.« less

Effect of surface moisture on chemically bonded phosphor for thermographic phosphor thermometry

NASA Astrophysics Data System (ADS)

Cai, Tao; Kim, Dong; Kim, Mirae; Liu, Ying Zheng; Kim, Kyung Chun

2016-09-01

This study examined the effect of surface moisture on the calibration lifetime in chemically bonded phosphor paint preparation. Mg4FGeO6:Mn was used as a sensor material, which was excited by a pulsed UV LED. A high-speed camera with a frequency of 8000 Hz was used to conduct phosphor thermometry. Five samples with different degrees of surface moisture were selected during the preparation process, and each sample was calibrated 40 times at room temperature. A conventional post-processing method was used to acquire the phosphorescent lifetime for different samples with a 4  ×  4-pixel interrogation window. The measurement error and paint uniformity were also studied. The results showed that there was no obvious phosphorescence boundary between the wet parts and dry parts of phosphor paint. The lifetime increased by about 0.0345% per hour during the preparation process, showing the degree of surface moisture had almost no influence on the lifetime measurement. The lifetime changed only after annealing treatment. There was also no effect on the measurement error and uniformity. These results provide a reference for developing a real-time measurement method using thermographic phosphor thermometry. This study also provides a feasible basis for chemically bonded phosphor thermometry applications in humid and low-temperature environments.

Colloidal lithography with electrochemical nickel deposition as a unique method for improved silver decorated nanocavities in SERS applications

NASA Astrophysics Data System (ADS)

Petruš, Ondrej; Oriňak, Andrej; Oriňaková, Renáta; Orságová Králová, Zuzana; Múdra, Erika; Kupková, Miriam; Kovaľ, Karol

2017-11-01

Two types of metallised nanocavities (single and hybrid) were fabricated by colloid lithography followed by electrochemical deposition of Ni and subsequently Ag layers. Introductory Ni deposition step iniciates more homogenous decoration of nanocavities with Ag nanoparticles. Silver nanocavity decoration has been so performed with lower nucleation rate and with Ag nanoparticles homogeinity increase. By this, two step Ni and Ag deposition trough polystyrene nanospheres (100, 300, 500, 700, 900 nm), the various Ag surfaces were obtained. Ni layer formation in the first step of deposition enabled more precise controlling of Ag film deposition and thus final Ag surface morphology. Prepared substrates were tested as active surfaces in SERS application. The best SERS signal enhancement was observed at 500 nm Ag nanocavities with normalised thickness Ni layer ∼0.5. Enhancement factor has been established at value 1.078 × 1010; time stability was determined within 13 weeks; charge distribution at nanocavity Ag surfaces as well as reflection spectra were calculated by FDTD method. Newly prepared nanocavity surface can be applied in SERS analysis, predominantly.

Preparation and characterization of Polyacrylonitrile/ Manganese Dioxides- based Carbon Nanofibers via electrospinning process

NASA Astrophysics Data System (ADS)

Che Othman, F. E.; Yusof, N.; Jaafar, J.; Ismail, A. F.; Hasbullah, H.; Abdullah, N.; Ismail, M. S.

2016-06-01

This research reports the production of precursor polyacrylonitrile (PAN)/ manganese dioxide (MnO2) nanofibers (NFs) via electrospinning method followed by stabilization and carbonization processes. Nowadays, electrospinning has become a suitable method in manufacturing continuous NFs, thus it is employed to fabricate NFs in this study. The microstructural properties and adsorption competencies of the produced NFs were also studied. The NFs were prepared by electrospinning the polymer solution of Polyacrylonitrile (PAN) and Manganese Dioxide (MnO2) in, N, N-Dimethylformamide (DMF) solvent. The factors considered in this study were various polymer PAN/MnO2 concentrations which will significantly affect the specific surface area, fiber morphology and the diameter of the NFs prepared. Subsequently, heat treatment is applied by setting up the stabilization temperature at 275 °C and carbonization temperature at 800 °C with constant dwelling time (30 min). Nitrogen gas at constant rate 0.2 L/min was used for stabilization and carbonization with the stabilization rate (2 °C/min) and carbonization rate (5 °C/min). The carbon nanofibers (CNFs) produced were characterized using Scanning Electron Microscopy (SEM), Brunauer Emmett and Teller (BET) surface area and Fourier Transmission Infrared Spectroscopy (FTIR). It was found that the PAN/MnO2 CNFs were successfully produced with the carbonization temperature of 800 °C. The prepared PAN/MnO2 CNFs prepared showed an enhanced in specific surface area about two times compared to it precursor NFs.

20 CFR 725.101 - Definition and use of terms.

Code of Federal Regulations, 2011 CFR

2011-04-01

... the surface of such land by any person, used in, or to be used in, or resulting from, the work of... means or method, and in the work of preparing the coal so extracted, and includes custom coal..., mixing, storing and loading of bituminous coal, lignite or anthracite, and such other work of preparing...

Preparation of TiO2-SiO2 via sol-gel method: Effect of Silica precursor on Catalytic and Photocatalytic properties

NASA Astrophysics Data System (ADS)

Fatimah, I.

2017-02-01

TiO2-SiO2have been synthesized by the sol-gel method from titanium isopropoxide and varied silica precursors: tetraethyl orthosilicate and tetra methyl ortho silicate. To study the effect of the precursor, prepared materials were characterized by X-ray diffraction, scanning electron microscopy, Diffuse Reflectance UV-vis optical absorption, and also gas sorption analysis. XRD patterns showed the formation of TiO2 anatase in the TiO2-SiO2 composite with different crystallite size from different silica precursor as well as the different surface morphology. The DRUV-vis absorption spectra exhibit similar band gap energy correspond to 3.21eV value while the surface area, pore volume and pore radius of the materials seems to be affected by the precursor. The higher specific surface area contributes to give the enhanced activity in phenol hydroxylation and methylene blue photodegradation.

MPN estimation of qPCR target sequence recoveries from whole cell calibrator samples.

PubMed

Sivaganesan, Mano; Siefring, Shawn; Varma, Manju; Haugland, Richard A

2011-12-01

DNA extracts from enumerated target organism cells (calibrator samples) have been used for estimating Enterococcus cell equivalent densities in surface waters by a comparative cycle threshold (Ct) qPCR analysis method. To compare surface water Enterococcus density estimates from different studies by this approach, either a consistent source of calibrator cells must be used or the estimates must account for any differences in target sequence recoveries from different sources of calibrator cells. In this report we describe two methods for estimating target sequence recoveries from whole cell calibrator samples based on qPCR analyses of their serially diluted DNA extracts and most probable number (MPN) calculation. The first method employed a traditional MPN calculation approach. The second method employed a Bayesian hierarchical statistical modeling approach and a Monte Carlo Markov Chain (MCMC) simulation method to account for the uncertainty in these estimates associated with different individual samples of the cell preparations, different dilutions of the DNA extracts and different qPCR analytical runs. The two methods were applied to estimate mean target sequence recoveries per cell from two different lots of a commercially available source of enumerated Enterococcus cell preparations. The mean target sequence recovery estimates (and standard errors) per cell from Lot A and B cell preparations by the Bayesian method were 22.73 (3.4) and 11.76 (2.4), respectively, when the data were adjusted for potential false positive results. Means were similar for the traditional MPN approach which cannot comparably assess uncertainty in the estimates. Cell numbers and estimates of recoverable target sequences in calibrator samples prepared from the two cell sources were also used to estimate cell equivalent and target sequence quantities recovered from surface water samples in a comparative Ct method. Our results illustrate the utility of the Bayesian method in accounting for uncertainty, the high degree of precision attainable by the MPN approach and the need to account for the differences in target sequence recoveries from different calibrator sample cell sources when they are used in the comparative Ct method. Published by Elsevier B.V.

Nanoarchitectures for Metal-Organic Framework-Derived Nanoporous Carbons toward Supercapacitor Applications.

PubMed

Salunkhe, Rahul R; Kaneti, Yusuf Valentino; Kim, Jeonghun; Kim, Jung Ho; Yamauchi, Yusuke

2016-12-20

The future advances of supercapacitors depend on the development of novel carbon materials with optimized porous structures, high surface area, high conductivity, and high electrochemical stability. Traditionally, nanoporous carbons (NPCs) have been prepared by a variety of methods, such as templated synthesis, carbonization of polymer precursors, physical and chemical activation, etc. Inorganic solid materials such as mesoporous silica and zeolites have been successfully utilized as templates to prepare NPCs. However, the hard-templating methods typically involve several synthetic steps, such as preparation of the original templates, formation of carbon frameworks, and removal of the original templates. Therefore, these methods are not favorable for large-scale production. Metal-organic frameworks (MOFs) with high surface areas and large pore volumes have been studied over the years, and recently, enormous efforts have been made to utilize MOFs for electrochemical applications. However, their low conductivity and poor stability still present major challenges toward their practical applications in supercapacitors. MOFs can be used as precursors for the preparation of NPCs with high porosity. Their parent MOFs can be prepared with endless combinations of organic and inorganic constituents by simple coordination chemistry, and it is possible to control their porous architectures, pore volumes, surface areas, etc. These unique properties of MOF-derived NPCs make them highly attractive for many technological applications. Compared with carbonaceous materials prepared using conventional precursors, MOF-derived carbons have significant advantages in terms of a simple synthesis with inherent diversity affording precise control over porous architectures, pore volumes, and surface areas. In this Account, we will summarize our recent research developments on the preparation of three-dimensional (3-D) MOF-derived carbons for supercapacitor applications. This Account will be divided into three main sections: (1) useful background on carbon materials for supercapacitor applications, (2) the importance of MOF-derived carbons, and (3) potential future developments of MOF-derived carbons for supercapacitors. This Account focuses mostly on carbons derived from two types of MOFs, namely, zeolite imidazolate framework-8 (ZIF-8) and ZIF-67. By using examples from our previous works, we will show the uniqueness of these carbons for achieving high performance by control of the chemical reactions/conditions as well proper utilization in asymmetric/symmetric supercapacitor configurations. This Account will promote further developments of MOF-derived multifunctional carbon materials with controlled porous architectures for optimization of their electrochemical performance toward supercapacitor applications.

Chemically stable and mechanically durable superamphiphobic aluminum surface with a micro/nanoscale binary structure.

PubMed

Peng, Shan; Yang, Xiaojun; Tian, Dong; Deng, Wenli

2014-09-10

We developed a simple fabrication method to prepare a superamphiphobic aluminum surface. On the basis of a low-energy surface and the combination of micro- and nanoscale roughness, the resultant surface became super-repellent toward a wide range of liquids with surface tensions of 25.3-72.1 mN m(-1). The applied approach involved (1) the formation of an irregular microplateau structure on an aluminum surface, (2) the fabrication of a nanoplatelet structure, and (3) fluorination treatment. The chemical stability and mechanical durability of the superamphiphobic surface were evaluated in detail. The results demonstrated that the surface presented an excellent chemical stability toward cool corrosive liquids (HCl/NaOH solutions, 25 °C) and 98% concentrated sulfuric acid, hot liquids (water, HCl/NaOH solutions, 30-100 °C), solvent immersion, high temperature, and a long-term period. More importantly, the surface also exhibited robust mechanical durability and could withstand multiple-fold, finger-touch, intensive scratching by a sharp blade, ultrasonication treatment, boiling treatment in water and coffee, repeated peeling by adhesive tape, and even multiple abrasion tests under 500 g of force without losing superamphiphobicity. The as-prepared superamphiphobic surface was also demonstrated to have excellent corrosion resistance. This work provides a simple, cost-effective, and highly efficient method to fabricate a chemically stable and mechanically robust superamphiphobic aluminum surface, which can find important outdoor applications.

Surface engineered nanoparticles for improved surface enhanced Raman scattering applications and method for preparing same

DOEpatents

Simmons, Blake A [San Francisco, CA; Talin, Albert Alec [Livermore, CA

2009-11-27

A method for producing metal nanoparticles that when associated with an analyte material will generate an amplified SERS spectrum when the analyte material is illuminated by a light source and a spectrum is recorded. The method for preparing the metal nanoparticles comprises the steps of (i) forming a water-in-oil microemulsion comprising a bulk oil phase, a dilute water phase, and one or more surfactants, wherein the water phase comprises a transition metal ion; (ii) adding an aqueous solution comprising a mild reducing agent to the water-in-oil microemulsion; (iii) stirring the water-in-oil microemulsion and aqueous solution to initiate a reduction reaction resulting in the formation of a fine precipitate dispersed in the water-in-oil microemulsion; and (iv) separating the precipitate from the water-in-oil microemulsion.

Comparison of preparation methods for ceria catalyst and the effect of surface and bulk sulfates on its activity toward NH3-SCR.

PubMed

Chang, Huazhen; Ma, Lei; Yang, Shijian; Li, Junhua; Chen, Liang; Wang, Wei; Hao, Jiming

2013-11-15

A series of CeO2 catalysts prepared with sulfate (S) and nitrate (N) precursors by hydrothermal (H) and precipitation (P) methods were investigated in selective catalytic reduction of NOx by NH3 (NH3-SCR). The catalytic activity of CeO2 was significantly affected by the preparation methods and the precursor type. CeO2-SH, which was prepared by hydrothermal method with cerium (IV) sulfate as a precursor, showed excellent SCR activity and high N2 selectivity in the temperature range of 230-450 °C. Based on the results obtained by temperature-programmed reduction (H2-TPR), transmission infrared spectra (IR) and thermal gravimetric analysis (TGA), the excellent performance of CeO2-SH was correlated with the surface sulfate species formed in the hydrothermal reaction. These results indicated that sulfate species bind with Ce(4+) on the CeO2-SH catalyst, and the specific sulfate species, such as Ce(SO4)2 or CeOSO4, were formed. The adsorption of NH3 was promoted by these sulfate species, and the probability of immediate oxidation of NH3 to N2O on Ce(4+) was reduced. Accordingly, the selective oxidation of NH3 was enhanced, which contributed to the high N2 selectivity in the SCR reaction. However, the location of sulfate on the CeO2-SP catalyst was different. Plenty of sulfate species were likely deposited on CeO2-SP surface, covering the active sites for NO oxidation, which resulted in poor SCR activity in the test temperature range. Moreover, the resistance to alkali metals, such as Na and K, was improved over the CeO2-SH catalyst. Copyright © 2013 Elsevier B.V. All rights reserved.

Sillica Gel-Amine from Geothermal Sludge

NASA Astrophysics Data System (ADS)

Muljani, S.; Pujiastuti, C.; Wicaksono, P.; Lutfianingrum, R.

2018-01-01

Silica Gel-Amine (SGA) has been made from geothermal sludge by grafting amine method. Sodium silicate solution is prepared by extracted geothermal sludge powder using sodium hidroxide solution then acidification in the range of pH 5 - 9 by using tartaric acid 1N. The grafting process uses 1 ml of ammonia solution and 10 ml of toluene at a rate of 0.1 ml min-1 accompanied by a reflux process. The amine grafting is done in two methods. The first method is grafting amine in silicate solution and the second method is grafting amine in washed gel. Product SGA was confirmed by FTIR, TGA-DTG and BET characterization. The results show that the pH affects the amount of amine that is grafted onto silica gel. Differences in grafting method affect the size of the pore and surface area. SGA product prepared by grafting washed gel at pH 8 have pore diameter of 12.06 nm, surface area of 173.44 m2g-1, and mass of decomposed amine compound 0.4 mg. In the presence of amine groups on the silica gel surface, these adsorbents may be able to selectively adsorb CO2 gas from natural gas.

The influence of surface roughness and high pressure torsion on the growth of anodic titania nanotubes on pure titanium

NASA Astrophysics Data System (ADS)

Hu, Nan; Gao, Nong; Starink, Marco J.

2016-11-01

Anodic titanium dioxide nanotube (TNT) arrays have wide applications in photocatalytic, catalysis, electronics, solar cells and biomedical implants. When TNT coatings are combined with severe plastic deformation (SPD), metal processing techniques which efficiently improve the strength of metals, a new generation of biomedical implant is made possible with both improved bulk and surface properties. This work investigated the effect of processing by high pressure torsion (HPT) and different mechanical preparations on the substrate and subsequently on the morphology of TNT layers. HPT processing was applied to refine the grain size of commercially pure titanium samples and substantially improved their strength and hardness. Subsequent anodization at 30 V in 0.25 wt.% NH4F for 2 h to form TNT layers on sample surfaces prepared with different mechanical preparation methods was carried out. It appeared that the local roughness of the titanium surface on a microscopic level affected the TNT morphology more than the macroscopic surface roughness. For HPT-processed sample, the substrate has to be pre-treated by a mechanical preparation finer than 4000 grit for HPT to have a significant influence on TNTs. During the formation of TNT layers the oxide dissolution rate was increased for the ultrafine-grained microstructure formed due to HPT processing.

Preparation of multifunctional Al-Mg alloy surface with hierarchical micro/nanostructures by selective chemical etching processes

NASA Astrophysics Data System (ADS)

Shi, Tian; Kong, Jianyi; Wang, Xingdong; Li, Xuewu

2016-12-01

A superamphiphobic aluminum magnesium alloy surface with enhanced anticorrosion behavior has been prepared in this work via a simple and low-cost method. By successively polishing, etching and boiling treatments, the multifunctional hierarchical binary structures composed of the labyrinth-like concave-convex microstructures and twisty nanoflakes have been prepared. Results indicate that a superhydrophobic contact angle of 160.5° and superoleophobic contact angle larger than 150° as well as low adhesive property to liquids are achieved after such structures being modified with fluoroalkyl-silane. Furthermore, the anticorrosion behaviors in seawater of as-prepared samples are characterized by electrochemical tests including the impedance spectroscopies, equivalent circuits fittings and polarization curves. It is found that the hierarchical micro/nanostructures accompanying with the modified coating are proved to possess the maximal coating coverage rate of 90.0% larger than microstructures of 85.9%, nanostructures of 83.8% and bare polished surface of 67.1% suggesting the optimal anticorrosion. Finally, a great potential application in concentrators for surface-enhanced Raman scattering (SERS) analysis of toxic and pollutive ions on the superamphiphobic surface is also confirmed. This work has wider significance in extending further applications of alloys in engineering and environmental detecting fields.

Surface Treatment of Plastic Substrates using Atomic Hydrogen Generated on Heated Tungsten Wire at Low Temperatures

NASA Astrophysics Data System (ADS)

Heya, Akira; Matsuo, Naoto

2007-06-01

The surface properties of a plastic substrate were changed by a novel surface treatment called atomic hydrogen annealing (AHA). In this method, a plastic substrate was exposed to atomic hydrogen generated by cracking hydrogen molecules on heated tungsten wire. For the substrate, surface roughness was increased and halogen elements (F and Cl) were selectively etched by AHA. AHA was useful for pretreatment before film deposition on a plastic substrate because the changes in surface state relate to adhesion improvement. It is concluded that this method is a promising technique for preparing high-performance plastic substrates at low temperatures.

Impurity concentrations and surface charge densities on the heavily doped face of a silicon solar cell

NASA Technical Reports Server (NTRS)

Weinberg, I.; Hsu, L. C.

1977-01-01

Increased solar cell efficiencies are attained by reduction of surface recombination and variation of impurity concentration profiles at the n(+) surface of silicon solar cells. Diagnostic techniques are employed to evaluate the effects of specific materials preparation methodologies on surface and near surface concentrations. It is demonstrated that the MOS C-V method, when combined with a bulk measurement technique, yields more complete concentration data than are obtainable by either method alone. Specifically, new solar cell MOS C-V measurements are combined with bulk concentrations obtained by a successive layer removal technique utilizing measurements of sheet resistivity and Hall coefficient.

Preparation and measurement methods for studying nanoparticle aggregate surface chemistry.

PubMed

Szakal, Christopher; McCarthy, James A; Ugelow, Melissa S; Konicek, Andrew R; Louis, Kacie; Yezer, Benjamin; Herzing, Andrew A; Hamers, Robert J; Holbrook, R David

2012-07-01

Despite best efforts at controlling nanoparticle (NP) surface chemistries, the environment surrounding nanomaterials is always changing and can impart a permanent chemical memory. We present a set of preparation and measurement methods to be used as the foundation for studying the surface chemical memory of engineered NP aggregates. We attempt to bridge the gap between controlled lab studies and real-world NP samples, specifically TiO(2), by using well-characterized and consistently synthesized NPs, controllably producing NP aggregates with precision drop-on-demand inkjet printing for subsequent chemical measurements, monitoring the physical morphology of the NP aggregate depositions with scanning electron microscopy (SEM), acquiring "surface-to-bulk" mass spectra of the NP aggregate surfaces with time-of-flight secondary ion mass spectrometry (ToF-SIMS), and developing a data analysis scheme to interpret chemical signatures more accurately from thousands of data files. We present differences in mass spectral peak ratios for bare TiO(2) NPs compared to NPs mixed separately with natural organic matter (NOM) or pond water. The results suggest that subtle changes in the local environment can alter the surface chemistry of TiO(2) NPs, as monitored by Ti(+)/TiO(+) and Ti(+)/C(3)H(5)(+) peak ratios. The subtle changes in the absolute surface chemistry of NP aggregates vs. that of the subsurface are explored. It is envisioned that the methods developed herein can be adapted for monitoring the surface chemistries of a variety of engineered NPs obtained from diverse natural environments.

Specimen preparation for x-ray fluorescence analysis of solutions

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

Eksperiandova, L.P.; Spolnik, Z.M.; Blank, A.B.

1995-12-31

Specimens for x-ray fluorescence analysis (XRFA) were prepared by adding dry gelatine (10%) to the analysis solution, homogenizing the mixture and cooling for 20 minutes. Thus, a compact resilient mass could be formed with the required shape and size; the roughness of the surface was determined by the roughness of the surface on which the specimen was formed, much the same as highly polished. Various calibration methods can be applied in the XRFA of a variety of materials if such specimens are used. 12 refs., 1 fig., 2 tabs.

Effects of consumer food preparation on acrylamide formation.

PubMed

Jackson, Lauren S; Al-Taher, Fadwa

2005-01-01

Acrylamide is formed in high-carbohydrate foods during high temperature processes such as frying, baking, roasting and extrusion. Although acrylamide is known to form during industrial processing of food, high levels of the chemical have been found in home-cooked foods, mainly potato- and grain-based products. This chapter will focus on the effects of cooking conditions (e.g. time/temperature) on acrylamide formation in consumer-prepared foods, the use of surface color (browning) as an indicator of acrylamide levels in some foods, and methods for reducing acrylamide levels in home-prepared foods. As with commercially processed foods, acrylamide levels in home-prepared foods tend to increase with cooking time and temperature. In experiments conducted at the NCFST, we found that acrylamide levels in cooked food depended greatly on the cooking conditions and the degree of "doneness", as measured by the level of surface browning. For example, French fries fried at 150-190 degrees C for up to 10 min had acrylamide levels of 55 to 2130 microg/kg (wet weight), with the highest levels in the most processed (highest frying times/temperatures) and the most highly browned fries. Similarly, more acrylamide was formed in "dark" toasted bread slices (43.7-610.7 microg/kg wet weight), than "light" (8.27-217.5 microg/kg) or "medium" (10.9-213.7 microg/kg) toasted slices. Analysis of the surface color by colorimetry indicated that some components of surface color ("a" and "L" values) correlated highly with acrylamide levels. This indicates that the degree of surface browning could be used as an indicator of acrylamide formation during cooking. Soaking raw potato slices in water before frying was effective at reducing acrylamide levels in French fries. Additional studies are needed to develop practical methods for reducing acrylamide formation in home-prepared foods without changing the acceptability of these foods.

Mesoporous magnetic activated carbon: Effect of preparation route on texture and surface properties and on effect for Reactive Black 5 adsorption.

NASA Astrophysics Data System (ADS)

Giannakoudakis, Dimitrios; Saroyan, Hayarpi; Lazaridis, Nikolaos; Deliyanni, Eleni

2016-04-01

Mesoporous magnetic activated carbon: Effect of preparation route on texture and surface properties and on effect for Reactive Black 5 adsorption. Dimitrios Giannakoudakis1, Hayarpi Saroyan2, Nikolaos Lazaridis2, Eleni Deliyanni2 1 City College of New York, Chemistry Department, 160 Convent Avenue, New York, United States 2 Laboratory of General and oInorganic Chemical Technology, Department of Chemistry, Aristotle University of Thessaloniki, GR-541 24 Thessaloniki, Greece In this study, the effect of preparation route of a mesoporous magnetic activated carbon on Reactive Black 5 (RB5) adsorption was investigated. The synthesis of the magnetic activated carbon was achieved both with (i) impregnation method (Bmi), and (ii) co-precipitation with two precipitation agents: NaOH (Bm) and NH4OH (Bma). After synthesis, the full characterization with various techniques (SEM, FTIR, XRD, DTA, DTG, VSM) was achieved in order to testify the effect of the preparation route on its textural and surface properties. It was shown that after the precipitation method the prepared carbon presented a collapsed texture and small magnetic properties. Effects of initial solution pH, effect of temperature, adsorption isotherms and kinetics were investigated in order to conclude about the aforementioned effect of the preparation method on dye adsorption performance of the magnetic carbons. The adsorption evaluation of the magnetic activated carbon presented higher adsorption capacity of Bmi carbon (350 mg/g) and lower of Bm (150 mg/g). Equilibrium experiments are also performed studying the effect of contact time (pseudo-first and -second order equations) and temperature (isotherms at 25, 45 and 65 °C fitted to Langmuir and Freundlich model). A full thermodynamic evaluation was carried out, calculating the parameters of enthalpy, free energy and entropy (ΔHο, ΔGο and ΔSο). The characterization with various techniques revealed the possible interactions/forces of dye-composite system.

Porous polymeric materials for hydrogen storage

DOEpatents

Yu, Luping [Hoffman Estates, IL; Liu, Di-Jia [Naperville, IL; Yuan, Shengwen [Chicago, IL; Yang, Junbing [Westmont, IL

2011-12-13

Porous polymers, tribenzohexazatriphenylene, poly-9,9'-spirobifluorene, poly-tetraphenyl methane and their derivatives for storage of H.sub.2 prepared through a chemical synthesis method. The porous polymers have high specific surface area and narrow pore size distribution. Hydrogen uptake measurements conducted for these polymers determined a higher hydrogen storage capacity at the ambient temperature over that of the benchmark materials. The method of preparing such polymers, includes oxidatively activating solids by CO.sub.2/steam oxidation and supercritical water treatment.

Porous polymeric materials for hydrogen storage

DOEpatents

Yu, Luping; Liu, Di-Jia; Yuan, Shengwen; Yang, Junbing

2013-04-02

A porous polymer, poly-9,9'-spirobifluorene and its derivatives for storage of H.sub.2 are prepared through a chemical synthesis method. The porous polymers have high specific surface area and narrow pore size distribution. Hydrogen uptake measurements conducted for these polymers determined a higher hydrogen storage capacity at the ambient temperature over that of the benchmark materials. The method of preparing such polymers, includes oxidatively activating solids by CO.sub.2/steam oxidation and supercritical water treatment.

In situ supported MnOx-CeOx on carbon nanotubes for the low-temperature selective catalytic reduction of NO with NH3

NASA Astrophysics Data System (ADS)

Zhang, Dengsong; Zhang, Lei; Shi, Liyi; Fang, Cheng; Li, Hongrui; Gao, Ruihua; Huang, Lei; Zhang, Jianping

2013-01-01

The MnOx and CeOx were in situ supported on carbon nanotubes (CNTs) by a poly(sodium 4-styrenesulfonate) assisted reflux route for the low-temperature selective catalytic reduction (SCR) of NO with NH3. X-Ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR) and NH3 temperature-programmed desorption (NH3-TPD) have been used to elucidate the structure and surface properties of the obtained catalysts. It was found that the in situ prepared catalyst exhibited the highest activity and the most extensive operating-temperature window, compared to the catalysts prepared by impregnation or mechanically mixed methods. The XRD and TEM results indicated that the manganese oxide and cerium oxide species had a good dispersion on the CNT surface. The XPS results demonstrated that the higher atomic concentration of Mn existed on the surface of CNTs and the more chemisorbed oxygen species exist. The H2-TPR results suggested that there was a strong interaction between the manganese oxide and cerium oxide on the surface of CNTs. The NH3-TPD results demonstrated that the catalysts presented a larger acid amount and stronger acid strength. In addition, the obtained catalysts exhibited much higher SO2-tolerance and improved the water-resistance as compared to that prepared by impregnation or mechanically mixed methods.The MnOx and CeOx were in situ supported on carbon nanotubes (CNTs) by a poly(sodium 4-styrenesulfonate) assisted reflux route for the low-temperature selective catalytic reduction (SCR) of NO with NH3. X-Ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HRTEM), X-ray photoelectron spectroscopy (XPS), H2 temperature-programmed reduction (H2-TPR) and NH3 temperature-programmed desorption (NH3-TPD) have been used to elucidate the structure and surface properties of the obtained catalysts. It was found that the in situ prepared catalyst exhibited the highest activity and the most extensive operating-temperature window, compared to the catalysts prepared by impregnation or mechanically mixed methods. The XRD and TEM results indicated that the manganese oxide and cerium oxide species had a good dispersion on the CNT surface. The XPS results demonstrated that the higher atomic concentration of Mn existed on the surface of CNTs and the more chemisorbed oxygen species exist. The H2-TPR results suggested that there was a strong interaction between the manganese oxide and cerium oxide on the surface of CNTs. The NH3-TPD results demonstrated that the catalysts presented a larger acid amount and stronger acid strength. In addition, the obtained catalysts exhibited much higher SO2-tolerance and improved the water-resistance as compared to that prepared by impregnation or mechanically mixed methods. Electronic supplementary information (ESI) available: SEM images and EDS analysis, TEM images, and XPS spectrum of samples. See DOI: 10.1039/c2nr33006g

Recent progress on RE2O3-Mo/W emission materials.

PubMed

Wang, Jinshu; Zhang, Xizhu; Liu, Wei; Cui, Yuntao; Wang, Yiman; Zhou, Meiling

2012-08-01

RE2O3-Mo/W cathodes were prepared by powder metallurgy method. La2O3-Y2O3-Mo cermet cathodes prepared by traditional sintering method and spark plasma sintering (SPS) exhibit different secondary emission properties. The La2O3-Y2O3-Mo cermet cathode prepared by SPS method has smaller grain size and exhibits better secondary emission performance. Monte carlo calculation results indicate that the secondary electron emission way of the cathode correlates with the grain size. Decreasing the grain size can decrease the positive charging effect of RE2O3 and thus is favorable for the escaping of secondary electrons to vacuum. The Scandia doped tungsten matrix dispenser cathode with a sub-micrometer microstructure of matrix with uniformly distributed nanometer-particles of Scandia has good thermionic emission property. Over 100 A/cm2 full space charge limited current density can be obtained at 950Cb. The cathode surface is covered by a Ba-Sc-O active surface layer with nano-particles distributing mainly on growth steps of W grains, leads to the conspicuous emission property of the cathode.

Microstructural characterization of Ti-6Al-4V alloy subjected to the duplex SMAT/plasma nitriding.

PubMed

Pi, Y; Faure, J; Agoda-Tandjawa, G; Andreazza, C; Potiron, S; Levesque, A; Demangel, C; Retraint, D; Benhayoune, H

2013-09-01

In this study, microstructural characterization of Ti-6Al-4V alloy, subjected to the duplex surface mechanical attrition treatment (SMAT)/nitriding treatment, leading to improve its mechanical properties, was carried out through novel and original samples preparation methods. Instead of acid etching which is limited for morphological characterization by scanning electron microscopy (SEM), an original ion polishing method was developed. Moreover, for structural characterization by transmission electron microscopy (TEM), an ion milling method based with the use of two ions guns was also carried out for cross-section preparation. To demonstrate the efficiency of the two developed methods, morphological investigations were done by traditional SEM and field emission gun SEM. This was followed by structural investigations through selected area electron diffraction (SAED) coupled with TEM and X-ray diffraction techniques. The results demonstrated that ionic polishing allowed to reveal a variation of the microstructure according to the surface treatment that could not be observed by acid etching preparation. TEM associated to SAED and X-ray diffraction provided information regarding the nanostructure compositional changes induced by the duplex SMAT/nitriding process. Copyright © 2013 Wiley Periodicals, Inc.

Method for preparing a sodium/sulfur cell

DOEpatents

Weiner, Steven A.

1978-01-01

A method for preparing a sodium/sulfur cell comprising (A) inserting a solid sodium slug, adapted to be connected to an external circuit, into the anodic reaction zone of a cell subassembly maintained within an inert atmosphere, said cell subassembly comprising a cell container and a tubular cation-permeable barrier disposed within said container such that a first reaction zone is located within cation-permeable barrier and a second reaction zone is located between the outer surface of said cation-permeable barrier and the inner surface of said container, one of said reaction zones being said anodic reaction zone and the other of said reaction zone being a cathodic reaction zone containing a precast composite cathodic reactant comprising a sulfur impregnated porous conductive material connected to said cation permeable barrier and adapted to be connected to said external circuit; and (B) providing closure means for said subassembly and sealing the same to said subassembly at a temperature less than about 100.degree. C. The method of the invention overcomes deficiencies of the prior art methods by allowing preparation of a sodium/sulfur cell without the use of molten reactants and the fill spouts which are required when the cell is filled with molten reactants.

Atomic force microscopy of adsorbed proteoglycan mimetic nanoparticles: Toward new glycocalyx-mimetic model surfaces.

PubMed

Hedayati, Mohammadhasan; Kipper, Matt J

2018-06-15

Blood vessels present a dense, non-uniform, polysaccharide-rich layer, called the endothelial glycocalyx. The polysaccharides in the glycocalyx include polyanionic glycosaminoglycans (GAGs). This polysaccharide-rich surface has excellent and unique blood compatibility. We report new methods for preparing and characterizing dense GAG surfaces that can serve as models of the vascular endothelial glycocalyx. The GAG-rich surfaces are prepared by adsorbing heparin or chondroitin sulfate-containing polyelectrolyte complex nanoparticles (PCNs) to chitosan-hyaluronan polyelectrolyte multilayers (PEMs). The surfaces are characterized by PeakForce tapping atomic force microscopy, both in air and in aqueous pH 7.4 buffer, and by PeakForce quantitative nanomechanics (PF-QNM) mode with high spatial resolution. These new surfaces provide access to heparin-rich or chondroitin sulfate-rich coatings that mimic both composition and nanoscale structural features of the vascular endothelial glycocalyx. Copyright © 2018. Published by Elsevier Ltd.

ELECTRODEPOSITION OF NICKEL ON URANIUM

DOEpatents

Gray, A.G.

1958-08-26

A method is described for preparing uranium objects prior to nickel electroplating. The process consiats in treating the surface of the uranium with molten ferric chloride hexahydrate, at a slightiy elevated temperature. This treatment etches the metal surface providing a structure suitable for the application of adherent electrodeposits and at the same time plates the surface with a thin protective film of iron.

Multifunctional thin film surface

DOEpatents

Brozik, Susan M.; Harper, Jason C.; Polsky, Ronen; Wheeler, David R.; Arango, Dulce C.; Dirk, Shawn M.

2015-10-13

A thin film with multiple binding functionality can be prepared on an electrode surface via consecutive electroreduction of two or more aryl-onium salts with different functional groups. This versatile and simple method for forming multifunctional surfaces provides an effective means for immobilization of diverse molecules at close proximities. The multifunctional thin film has applications in bioelectronics, molecular electronics, clinical diagnostics, and chemical and biological sensing.

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.

Multifunctional substrate of Al alloy based on general hierarchical micro/nanostructures: superamphiphobicity and enhanced corrosion resistance.

PubMed

Li, Xuewu; Shi, Tian; Liu, Cong; Zhang, Qiaoxin; Huang, Xingjiu

2016-10-24

Aluminum alloys are vulnerable to penetrating and peeling failures in seawater and preparing a barrier coating to isolate the substrate from corrosive medium is an effective anticorrosion method. Inspired by the lotus leaves effect, a wetting alloy surface with enhanced anticorrosion behavior has been prepared via etch, deposition, and low-surface-energy modification. Results indicate that excellent superamphiphobicity has been achieved after the modification of the constructed hierarchical labyrinth-like microstructures and dendritic nanostructures. The as-prepared surface is also found with good chemical stability and mechanical durability. Furthermore, superior anticorrosion behaviors of the resultant samples in seawater are investigated by electrochemical measurements. Due to trapped air in micro/nanostructures, the newly presented solid-air-liquid contacting interface can help to resist the seawater penetration by greatly reducing the interface interaction between corrosive ions and the superamphiphobic surface. Finally, an optimized two-layer perceptron artificial neural network is set up to model and predict the cause-and-effect relationship between preparation conditions and the anticorrosion parameters. This work provides a great potential to extend the applications of aluminum alloys especially in marine engineering fields.

Multifunctional substrate of Al alloy based on general hierarchical micro/nanostructures: superamphiphobicity and enhanced corrosion resistance

PubMed Central

Li, Xuewu; Shi, Tian; Liu, Cong; Zhang, Qiaoxin; Huang, Xingjiu

2016-01-01

Aluminum alloys are vulnerable to penetrating and peeling failures in seawater and preparing a barrier coating to isolate the substrate from corrosive medium is an effective anticorrosion method. Inspired by the lotus leaves effect, a wetting alloy surface with enhanced anticorrosion behavior has been prepared via etch, deposition, and low-surface-energy modification. Results indicate that excellent superamphiphobicity has been achieved after the modification of the constructed hierarchical labyrinth-like microstructures and dendritic nanostructures. The as-prepared surface is also found with good chemical stability and mechanical durability. Furthermore, superior anticorrosion behaviors of the resultant samples in seawater are investigated by electrochemical measurements. Due to trapped air in micro/nanostructures, the newly presented solid-air-liquid contacting interface can help to resist the seawater penetration by greatly reducing the interface interaction between corrosive ions and the superamphiphobic surface. Finally, an optimized two-layer perceptron artificial neural network is set up to model and predict the cause-and-effect relationship between preparation conditions and the anticorrosion parameters. This work provides a great potential to extend the applications of aluminum alloys especially in marine engineering fields. PMID:27775053

Multifunctional substrate of Al alloy based on general hierarchical micro/nanostructures: superamphiphobicity and enhanced corrosion resistance

NASA Astrophysics Data System (ADS)

Li, Xuewu; Shi, Tian; Liu, Cong; Zhang, Qiaoxin; Huang, Xingjiu

2016-10-01

Aluminum alloys are vulnerable to penetrating and peeling failures in seawater and preparing a barrier coating to isolate the substrate from corrosive medium is an effective anticorrosion method. Inspired by the lotus leaves effect, a wetting alloy surface with enhanced anticorrosion behavior has been prepared via etch, deposition, and low-surface-energy modification. Results indicate that excellent superamphiphobicity has been achieved after the modification of the constructed hierarchical labyrinth-like microstructures and dendritic nanostructures. The as-prepared surface is also found with good chemical stability and mechanical durability. Furthermore, superior anticorrosion behaviors of the resultant samples in seawater are investigated by electrochemical measurements. Due to trapped air in micro/nanostructures, the newly presented solid-air-liquid contacting interface can help to resist the seawater penetration by greatly reducing the interface interaction between corrosive ions and the superamphiphobic surface. Finally, an optimized two-layer perceptron artificial neural network is set up to model and predict the cause-and-effect relationship between preparation conditions and the anticorrosion parameters. This work provides a great potential to extend the applications of aluminum alloys especially in marine engineering fields.

Nanostructured Metal Oxides for Stoichiometric Degradation of Chemical Warfare Agents.

PubMed

Štengl, Václav; Henych, Jiří; Janoš, Pavel; Skoumal, Miroslav

2016-01-01

Metal oxides have very important applications in many areas of chemistry, physics and materials science; their properties are dependent on the method of preparation, the morphology and texture. Nanostructured metal oxides can exhibit unique characteristics unlike those of the bulk form depending on their morphology, with a high density of edges, corners and defect surfaces. In recent years, methods have been developed for the preparation of metal oxide powders with tunable control of the primary particle size as well as of a secondary particle size: the size of agglomerates of crystallites. One of the many ways to take advantage of unique properties of nanostructured oxide materials is stoichiometric degradation of chemical warfare agents (CWAs) and volatile organic compounds (VOC) pollutants on their surfaces.

Optimization of Preparation of Antioxidative Peptides from Pumpkin Seeds Using Response Surface Method

PubMed Central

Fan, Sanhong; Hu, Yanan; Li, Chen; Liu, Yanrong

2014-01-01

Protein isolates of pumpkin (Cucurbita pepo L) seeds were hydrolyzed by acid protease to prepare antioxidative peptides. The hydrolysis conditions were optimized through Box-Behnken experimental design combined with response surface method (RSM). The second-order model, developed for the DPPH radical scavenging activity of pumpkin seed hydrolysates, showed good fit with the experiment data with a high value of coefficient of determination (0.9918). The optimal hydrolysis conditions were determined as follows: hydrolyzing temperature 50°C, pH 2.5, enzyme amount 6000 U/g, substrate concentration 0.05 g/ml and hydrolyzing time 5 h. Under the above conditions, the scavenging activity of DPPH radical was as high as 92.82%. PMID:24637721

Antibacterial properties of Ag-doped hydroxyapatite layers prepared by PLD method

NASA Astrophysics Data System (ADS)

Jelínek, Miroslav; Kocourek, Tomáš; Jurek, Karel; Remsa, Jan; Mikšovský, Jan; Weiserová, Marie; Strnad, Jakub; Luxbacher, Thomas

2010-12-01

Thin hydroxyapatite (HA), silver-doped HA and silver layers were prepared using a pulsed laser deposition method. Doped layers were ablated from silver/HA targets. Amorphous and crystalline films of silver concentrations of 0.06 at.%, 1.2 at.%, 4.4 at.%, 8.3 at.% and 13.7 at.% were synthesized. Topology was studied using scanning electron microscopy and atomic force microscopy. Contact angle and zeta potential measurements were conducted to determine the wettability, surface free energy and electric surface properties. In vivo measurement (using Escherichia coli cells) of antibacterial properties of the HA, silver-doped HA and silver layers was carried out. The best antibacterial results were achieved for silver-doped HA layers of silver concentration higher than 1.2 at.%.

Seed-Surface Grafting Precipitation Polymerization for Preparing Microsized Optically Active Helical Polymer Core/Shell Particles and Their Application in Enantioselective Crystallization.

PubMed

Zhao, Biao; Lin, Jiangfeng; Deng, Jianping; Liu, Dong

2018-05-14

Core/shell particles constructed by polymer shell and silica core have constituted a significant category of advanced functional materials. However, constructing microsized optically active helical polymer core/shell particles still remains as a big academic challenge due to the lack of effective and universal preparation methods. In this study, a seed-surface grafting precipitation polymerization (SSGPP) strategy is developed for preparing microsized core/shell particles with SiO 2 as core on which helically substituted polyacetylene is covalently bonded as shell. The resulting core/shell particles exhibit fascinating optical activity and efficiently induce enantioselective crystallization of racemic threonine. Taking advantage of the preparation strategy, novel achiral polymeric and hybrid core/shell particles are also expected. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Surface functionalized nanofibrillar cellulose (NFC) film as a platform for immunoassays and diagnostics.

PubMed

Orelma, Hannes; Filpponen, Ilari; Johansson, Leena-Sisko; Osterberg, Monika; Rojas, Orlando J; Laine, Janne

2012-12-01

We introduce a new method to modify films of nanofibrillated cellulose (NFC) to produce non-porous, water-resistant substrates for diagnostics. First, water resistant NFC films were prepared from mechanically disintegrated NFC hydrogel, and then their surfaces were carboxylated via TEMPO-mediated oxidation. Next, the topologically functionalized film was activated via EDS/NHS chemistry, and its reactivity verified with bovine serum albumin and antihuman IgG. The surface carboxylation, EDC/NHS activation and the protein attachment were confirmed using quartz crystal microbalance with dissipation, contact angle measurements, conductometric titrations, X-ray photoelectron spectroscopy and fluorescence microscopy. The surface morphology of the prepared films was investigated using confocal laser scanning microscopy and atomic force microscopy. Finally, we demonstrate that antihuman IgG can be immobilized on the activated NFC surface using commercial piezoelectric inkjet printing.

Preparation, anti-biofouling and drag-reduction properties of a biomimetic shark skin surface

PubMed Central

Pu, Xia; Li, Guangji; Huang, Hanlu

2016-01-01

ABSTRACT Shark skin surfaces show non-smoothness characteristics due to the presence of a riblet structure. In this study, biomimetic shark skin was prepared by using the polydimethylsiloxane (PDMS)-embedded elastomeric stamping (PEES) method. Scanning electron microscopy (SEM) was used to examine the surface microstructure and fine structure of shark skin and biomimetic shark skin. To analyse the hydrophobic mechanism of the shark skin surface microstructure, the effect of biomimetic shark skin surface microstructure on surface wettability was evaluated by recording water contact angle. Additionally, protein adhesion experiments and anti-algae adhesion performance testing experiments were used to investigate and evaluate the anti-biofouling properties of the surface microstructure of biomimetic shark skin. The recorded values of the water contact angle of differently microstructured surfaces revealed that specific microstructures have certain effects on surface wettability. The anti-biofouling properties of the biomimetic shark skin surface with microstructures were superior to a smooth surface using the same polymers as substrates. Moreover, the air layer fixed on the surface of the biomimetic shark skin was found to play a key role in their antibiont adhesion property. An experiment into drag reduction was also conducted. Based on the experimental results, the microstructured surface of the prepared biomimetic shark skin played a significant role in reducing drag. The maximum of drag reduction rate is 12.5%, which is higher than the corresponding maximum drag reduction rate of membrane material with a smooth surface. PMID:26941105

Preparation, anti-biofouling and drag-reduction properties of a biomimetic shark skin surface.

PubMed

Pu, Xia; Li, Guangji; Huang, Hanlu

2016-04-15

Shark skin surfaces show non-smoothness characteristics due to the presence of a riblet structure. In this study, biomimetic shark skin was prepared by using the polydimethylsiloxane (PDMS)-embedded elastomeric stamping (PEES) method. Scanning electron microscopy (SEM) was used to examine the surface microstructure and fine structure of shark skin and biomimetic shark skin. To analyse the hydrophobic mechanism of the shark skin surface microstructure, the effect of biomimetic shark skin surface microstructure on surface wettability was evaluated by recording water contact angle. Additionally, protein adhesion experiments and anti-algae adhesion performance testing experiments were used to investigate and evaluate the anti-biofouling properties of the surface microstructure of biomimetic shark skin. The recorded values of the water contact angle of differently microstructured surfaces revealed that specific microstructures have certain effects on surface wettability. The anti-biofouling properties of the biomimetic shark skin surface with microstructures were superior to a smooth surface using the same polymers as substrates. Moreover, the air layer fixed on the surface of the biomimetic shark skin was found to play a key role in their antibiont adhesion property. An experiment into drag reduction was also conducted. Based on the experimental results, the microstructured surface of the prepared biomimetic shark skin played a significant role in reducing drag. The maximum of drag reduction rate is 12.5%, which is higher than the corresponding maximum drag reduction rate of membrane material with a smooth surface. © 2016. Published by The Company of Biologists Ltd.

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.

Nanoporous Gold for Enzyme Immobilization.

PubMed

Stine, Keith J; Jefferson, Kenise; Shulga, Olga V

2017-01-01

Nanoporous gold (NPG) is a material of emerging interest for immobilization of biomolecules, especially enzymes. The material provides a high surface area form of gold that is suitable for physisorption or for covalent modification by self-assembled monolayers. The material can be used as a high surface area electrode and with immobilized enzymes can be used for amperometric detection schemes. NPG can be prepared in a variety of formats from alloys containing between 20 and 50 % atomic composition of gold and less noble element(s) by dealloying procedures. Materials resembling NPG can be prepared by hydrothermal and electrodeposition methods. Related high surface area gold structures have been prepared using templating approaches. Covalent enzyme immobilization can be achieved by first forming a self-assembled monolayer on NPG bearing a terminal reactive functional group followed by conjugation to the enzyme through amide linkages to lysine residues. Enzymes can also be entrapped by physisorption or immobilized by electrostatic interactions.

Tunable laser interference lithography preparation of plasmonic nanoparticle arrays tailored for SERS.

PubMed

Gisbert Quilis, Nestor; Lequeux, Médéric; Venugopalan, Priyamvada; Khan, Imran; Knoll, Wolfgang; Boujday, Souhir; Lamy de la Chapelle, Marc; Dostalek, Jakub

2018-05-23

The facile preparation of arrays of plasmonic nanoparticles over a square centimeter surface area is reported. The developed method relies on tailored laser interference lithography (LIL) that is combined with dry etching and it offers means for the rapid fabrication of periodic arrays of metallic nanostructures with well controlled morphology. Adjusting the parameters of the LIL process allows for the preparation of arrays of nanoparticles with a diameter below hundred nanometers independently of their lattice spacing. Gold nanoparticle arrays were precisely engineered to support localized surface plasmon resonance (LSPR) with different damping at desired wavelengths in the visible and near infrared part of the spectrum. The applicability of these substrates for surface enhanced Raman scattering is demonstrated where cost-effective, uniform and reproducible substrates are of paramount importance. The role of deviations in the spectral position and the width of the LSPR band affected by slight variations of plasmonic nanostructures is discussed.

Optimization of preparation of activated carbon from cotton stalk by microwave assisted phosphoric acid-chemical activation.

PubMed

Deng, Hui; Zhang, Genlin; Xu, Xiaolin; Tao, Guanghui; Dai, Jiulei

2010-10-15

The preparation of activated carbon (AC) from cotton stalk was investigated in this paper. Orthogonal array experimental design method was used to optimize the preparation of AC using microwave assisted phosphoric acid. Optimized parameters were radiation power of 400 W, radiation time of 8 min, concentration of phosphoric acid of 50% by volume and impregnation time of 20 h, respectively. The surface characteristics of the AC prepared under optimized condition were examined by pore structure analysis, scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FT-IR). Pore structure analysis shows that mecropores constitute more of the porosity of the prepared AC. Compared to cotton stalk, different functionalities and morphology on the carbon surfaces were formed in the prepared process. The adsorption capacity of the AC was also investigated by removing methylene blue (MB) in aqueous solution. The equilibrium data of the adsorption was well fitted to the Langmuir isotherm. The maximum adsorption capacity of MB on the prepared AC is 245.70 mg/g. The adsorption process follows the pseudo-second-order kinetic model. 2010 Elsevier B.V. All rights reserved.

Surface Structure Spread Single Crystals (S4C): Preparation and characterization

NASA Astrophysics Data System (ADS)

de Alwis, A.; Holsclaw, B.; Pushkarev, V. V.; Reinicker, A.; Lawton, T. J.; Blecher, M. E.; Sykes, E. C. H.; Gellman, A. J.

2013-02-01

A set of six spherically curved Cu single crystals referred to as Surface Structure Spread Single Crystals (S4Cs) has been prepared in such a way that their exposed surfaces collectively span all possible crystallographic surface orientations that can be cleaved from the face centered cubic Cu lattice. The method for preparing these S4Cs and for finding the high symmetry pole point is described. Optical profilometry has been used to determine the true shapes of the S4Cs and show that over the majority of the surface, the shape is extremely close to that of a perfect sphere. The local orientations of the surfaces lie within ± 1° of the orientation expected on the basis of the spherical shape; their orientation is as good as that of many commercially prepared single crystals. STM imaging has been used to characterize the atomic level structure of the Cu(111) ± 11°-S4C. This has shown that the average step densities and the average step orientations match those expected based on the spherical shape. In other words, although there is some distribution of step-step spacing and step orientations, there is no evidence of large scale reconstruction or faceting. The Cu S4Cs have local structures based on the ideal termination of the face centered cubic Cu lattice in the direction of termination. The set of Cu S4Cs will serve as the basis for high throughput investigations of structure sensitive surface chemistry on Cu.

Fast modification on wheat straw outer surface by water vapor plasma and its application on composite material.

PubMed

Chen, Weimin; Xu, Yicheng; Shi, Shukai; Cao, Yizhong; Chen, Minzhi; Zhou, Xiaoyan

2018-02-02

The presence of non-poplar extracts, cutin, and wax layer in the wheat straw outer surface (WOS) greatly limit its application in bio-composite preparation. In this study, a dielectric-barrier-discharge plasma using water vapor as feeding gas was used to fast modify the WOS. The morphology, free radical concentrations, surface chemical components, and contact angles of WOS before and after plasma modification were investigated. Wheat straw was further prepared into wheat straw-based composites (WSC) and its bonding strength was evaluated by a paper tension meter. The results showed that water vapor plasma leads to the appearance of surface roughness, the generation of massive free radicals, and the introduction of oxygen-containing groups. In addition, both initial and equilibrium contact angle and the surface total free energy were significantly increased after plasma modification. These results synergistically facilitate the spread and permeation of adhesive onto the WOS and thus improve the bonding strength of all prepared WSCs. A good linear relationship between bonding strength and surface roughness parameters, contact angles, and total free energy were observed. In general, this study provided a time-saving and cost-effective modification method to realize WSC manufacture.

Surface segregation of additives on SnO 2 based powders and their relationship with macroscopic properties

NASA Astrophysics Data System (ADS)

Pereira, Gilberto J.; Castro, Ricardo H. R.; Hidalgo, Pilar; Gouvêa, Douglas

2002-07-01

Surface properties of ceramic powders frequently play an important role in producing high-quality, high-performance, and reliable ceramic products. These properties are related to the surface bond types and interactions with the surroundings. Oxide surfaces generally contain adsorbed hydroxyl groups and modifications in the chemical composition of the surface may be studied by infrared spectroscopy. In this work, we prepared SnO 2 containing Fe or Mg ions by organic chemical route derived from Pechini's method. The prepared powders were characterized by infrared spectroscopy (FT-IR), X-ray diffraction (XRD), dynamic electrophoretic mobility and surface area determination. Results demonstrated that the studied additives segregate onto the oxide surface and modify the hydroxyl IR bands of the adsorbed hydroxyl groups. These surface modifications change some macroscopic properties of the powder such as the isoelectric point (IEP) in aqueous suspensions and the final specific surface area. The increase of the surface area with additive concentration is supposedly due to the reduction of surface energy of the powders when additives segregate on the powder surface.

Enhanced Photocatalytic Activity of Bismuth Precursor by Rapid Phase and Surface Transformation Using Structure-Guided Combustion Waves.

PubMed

Lee, Kang Yeol; Hwang, Hayoung; Kim, Tae Ho; Choi, Wonjoon

2016-02-10

The development of an efficient method for manipulating phase and surface transformations would facilitate the improvement of catalytic materials for use in a diverse range of applications. Herein, we present the first instance of a submicrosecond time frame direct phase and surface transformation of Bi(NO3)3 rods to nanoporous β-Bi2O3 rods via structure-guided combustion waves. Hybrid composites of the prepared Bi(NO3)3·H2O rods and organic fuel were fabricated by a facile preparation method. The anisotropic propagation of combustion waves along the interfacial boundaries of Bi(NO3)3·H2O rods induced direct phase transformation to β-Bi2O3 rods in the original structure due to the rapid pyrolysis, while the release of gas molecules enabled the formation of nanoporous structures on the surfaces of rods. The developed β-Bi2O3 rods showed improved photocatalytic activity for the photodegradation of rhodamine B in comparison with Bi(NO3)3·H2O rods and α-Bi2O3 rods due to the more suitable interdistance and the large contact areas of the porous surfaces. This new method of using structure-guided combustion waves for phase and surface transformation may contribute to the development of new catalysts as well as the precise manipulation of diverse micronanostructured materials.

An assessment of cleaning and sampling methods for food-contact surfaces in premises preparing and selling high-risk foods.

PubMed Central

Tebbutt, G. M.

1991-01-01

The performance of agar-contact plates and an alginate-swab method for sampling food surfaces before and after cleaning was compared. Contact plates were more convenient, and were at least as sensitive as the swabbing method. To assess cleaning efficiency repeated sampling was carried out in selected premises, and several cleaning methods were introduced for trial periods. Some surfaces, notably wood and polypropylene, were particularly difficult to clean. For these scrubbing with a nylon brush was the best method. Other surfaces were more easily cleaned, and generally the methods introduced as part of this study were better than the original method used in the premises. Paper proved to be unpopular, and cleaning solutions applied with it did no better than those cleaned with a multiuse cloth kept soaking in a detergent and hypochlorite solution. PMID:1850362

Antifouling enhancement of polysulfone/TiO2 nanocomposite separation membrane by plasma etching

NASA Astrophysics Data System (ADS)

Chen, Z.; Yin, C.; Wang, S.; Ito, K.; Fu, Q. M.; Deng, Q. R.; Fu, P.; Lin, Z. D.; Zhang, Y.

2017-01-01

A polysulfone/TiO2 nanocomposite membrane was prepared via casting method, followed by the plasma etching of the membrane surface. Doppler broadened energy spectra vs. positron incident energy were employed to elucidate depth profiles of the nanostructure for the as-prepared and treated membranes. The results confirmed that the near-surface of the membrane was modified by the plasma treatment. The antifouling characteristics for the membranes, evaluated using the degradation of Rhodamin B, indicated that the plasma treatment enhances the photo catalytic ability of the membrane, suggesting that more TiO2 nanoparticles are exposed at the membrane surface after the plasma treatment as supported by the positron result.

Formation and properties of surface-anchored polymer assemblies with tunable physico-chemical characteristics

NASA Astrophysics Data System (ADS)

Wu, Tao

We describe two new methodologies leading to the formation of novel surface-anchored polymer assemblies on solid substrates. While the main goal is to understand the fundamentals pertaining to the preparation and properties of the surface-bound polymer assemblies (including neutral and chargeable polymers), several examples also are mentioned throughout the Thesis that point out to practical applications of such structures. The first method is based on generating assemblies comprising anchored polymers with a gradual variation of grafting densities on solid substrates. These structures are prepared by first covering the substrate with a molecular gradient of the polymerization initiator, followed by polymerization from these substrate-bound initiator centers ("grafting from"). We apply this technique to prepare grafting density gradients of poly(acryl amide) (PAAm) and poly(acrylic acid) (PAA) on silica-covered substrates. We show that using the grafting density gradient geometry, the characteristics of surface-anchored polymers in both the low grafting density ("mushroom") regime as well as the high grafting density ("brush") regime can be accessed conveniently on a single sample. We use a battery of experimental methods, including Fourier transform infrared spectroscopy (FTIR), Near-edge absorption fine structure spectroscopy (NEXAFS), contact angle, ellipsometry, to study the characteristics of the surface-bound polymer layers. We also probe the scaling laws of neutral polymer as a function of grafting density, and for weak polyelectrolyte, in addition to the grafting density, we study the affect of solution ionic strength and pH values. In the second novel method, which we coined as "mechanically assisted polymer assembly" (MAPA), we form surface anchored polymers by "grafting from" polymerization initiators deposited on elastic surfaces that have been previously extended uniaxially by a certain length increment, Deltax. Upon releasing the strain in the substrate after completion of polymerization, we show the grafting density of the polymers grafted to flexible substrates can be tuned as a function of Deltax.

Preparation of a Superhydrophobic and Peroxidase-like Activity Array Chip for H2O2 Sensing by Surface-Enhanced Raman Scattering.

PubMed

Yu, Zhi; Park, Yeonju; Chen, Lei; Zhao, Bing; Jung, Young Mee; Cong, Qian

2015-10-28

In this paper, we propose a novel and simple method for preparing a dual-biomimetic functional array possessing both superhydrophobic and peroxidase-like activity that can be used for hydrogen peroxide (H2O2) sensing. The proposed method is an integration innovation that combines the above two properties and surface-enhanced Raman scattering (SERS). We integrated a series of well-ordered arrays of Au points (d = 1 mm) onto a superhydrophobic copper (Cu)/silver (Ag) surface by replicating an arrayed molybdenum template. Instead of using photoresists and the traditional lithography method, we utilized a chemical etching method (a substitution reaction between Cu and HAuCl4) with a Cu/Ag superhydrophobic surface as the barrier layer, which has the benefit of water repellency. The as-prepared Au points were observed to possess peroxidase-like activity, allowing for catalytic oxidation of the chromogenic molecule o-phenylenediamine dihydrochloride (OPD). Oxidation was evidenced by a color change in the presence of H2O2, which allows the array chip to act as an H2O2 sensor. In this study, the water repellency of the superhydrophobic surface was used to fabricate the array chip and increase the local reactant concentration during the catalytic reaction. As a result, the catalytic reaction occurred when only 2 μL of an aqueous sample (OPD/H2O2) was placed onto the Au point, and the enzymatic product, 2,3-diaminophenazine, showed a SERS signal distinguishable from that of OPD after mixing with 2 μL of colloidal Au. Using the dual-biomimetic functional array chip, quantitative analysis of H2O2 was performed by observing the change in the SERS spectra, which showed a concentration-dependent behavior for H2O2. This method allows for the detection of H2O2 at concentrations as low as 3 pmol per 2 μL of sample, which is a considerable advantage in H2O2 analysis. The as-prepared substrate was convenient for H2O2 detection because only a small amount of sample was required in each analysis. Highly sensitive detection was realized using SERS. Therefore, this chip was shown to exhibit significant potential for applications in bioanalysis.

Development of Al2O3 electrospun fibers prepared by conventional sintering method or plasma assisted surface calcination

NASA Astrophysics Data System (ADS)

Mudra, E.; Streckova, M.; Pavlinak, D.; Medvecka, V.; Kovacik, D.; Kovalcikova, A.; Zubko, P.; Girman, V.; Dankova, Z.; Koval, V.; Duzsa, J.

2017-09-01

In this paper, the electrospinning method was used for preparation of α-Al2O3 microfibers from PAN/Al(NO3)3 precursor solution. The precursor fibers were thermally treated by conventional method in furnace or low-temperature plasma induced surface sintering method in ambient air. The four different temperatures of PAN/Al(NO3)3 precursors were chosen for formation of α-Al2O3 phase by conventional sintering way according to the transition features observed in the TG/DSC analysis. In comparison, the low-temperature plasma treatment at atmospheric pressure was used as an alternative sintering method at the exposure times of 5, 10 and 30 min. FTIR analysis was used for evaluation of residual polymer after plasma induced calcination and for studying the mechanism of polymer degradation. The polycrystalline alumina fibers arranged with the nanoparticles was created continuously throughout the whole volume of the sample. On the other side the low temperature approach, high density of reactive species and high power density of plasma generated at atmospheric pressure by used plasma source allowed rapid removal of polymer in preference from the surface of fibers leading to the formation of composite ceramic/polymer fibers. This plasma induced sintering of PAN/Al(NO3)3 can have obvious importance in industrial applications where the ceramic character of surface with higher toughness of the fibers are required.

Fabrication of silk fibroin film using centrifugal casting technique for corneal tissue engineering.

PubMed

Lee, Min Chae; Kim, Dong-Kyu; Lee, Ok Joo; Kim, Jung-Ho; Ju, Hyung Woo; Lee, Jung Min; Moon, Bo Mi; Park, Hyun Jung; Kim, Dong Wook; Kim, Su Hyeon; Park, Chan Hum

2016-04-01

Films prepared from silk fibroin have shown potential as biomaterials in tissue engineering applications for the eye. Here, we present a novel process for fabrication of silk fibroin films for corneal application. In this work, fabrication of silk fibroin films was simply achieved by centrifugal force. In contrast to the conventional dry casting method, we carried out the new process in a centrifuge with a rotating speed of 4000 rpm, where centrifugal force was imposed on an aluminum tube containing silk fibroin solution. In the present study, we also compared the surface roughness, mechanical properties, transparency, and cell proliferation between centrifugal and dry casting method. In terms of surface morphology, films fabricated by the centrifugal casting have less surface roughness than those by the dry casting. For elasticity and transparency, silk fibroin films obtained from the centrifugal casting had favorable results compared with those prepared by dry casting. Furthermore, primary human corneal keratocytes grew better in films prepared by the centrifugal casting. Therefore, our results suggest that this new fabrication process for silk fibroin films offers important potential benefits for corneal tissue regeneration. © 2015 Wiley Periodicals, Inc.

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.

Preparation of novel multi-walled carbon nanotubes nanocomposite adsorbent via RAFT technique for the adsorption of toxic copper ions.

PubMed

Hosseinzadeh, Hossein; Pashaei, Shahryar; Hosseinzadeh, Soleyman; Khodaparast, Zahra; Ramin, Sonia; Saadat, Younes

2018-05-31

In the present work, polymer-coated multiwalled carbon nanotube (MWCNT) was prepared via RAFT method. First, a novel trithiocarbonate-based RAFT agent was prepared attached chemically into the surface of MWCNT. In addition, the RAFT co-polymerization of acrylic acid and acrylamide monomers was conducted through the prepared RAFT agent. In the next age, the surface morphology and chemical properties of the prepared components were fully examined by using FTIR, 1 HNMR, SEM, TEM, XRD and TGA/DTG techniques. Finally, the modified MWCNT composite was employed as an excellent adsorbent for the adsorption of copper (II) ions. The results indicated that ion adsorption basically relies on adsorbing time, solution pH, initial copper concentration, and adsorbent dosage. Further, the adsorption kinetics and isotherm analysis demonstrated that the adsorption mode was fitted with the pseudo-second-order and Langmuir isotherm models, respectively. Based on the results of thermodynamic study, the ion adsorption process was endothermic and spontaneous. Finally, based on the experimental results, the surface functionalized MWCNT with hydrophilic groups could be successfully used as a promising selective adsorbent material in wastewater treatment. Copyright © 2018 Elsevier B.V. All rights reserved.

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.

Thermoluminescence property of nano scale Al{sub 2}O{sub 3}: C by combustion method

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

Bharthasaradhi, R.; Nehru, L. C.

In this study, thermoluminescence dosimetry material of carbon doped aluminium oxide by combustion method using Aluminium nitrate and Glycine. The Structure of the prepared Sample was carried out by XRD. The sample was nano crystalline in nature. Having hexagonal structure with unit cell parameters a=4.75Å, C=12.99Å. The surface morphology of the prepared nanopowder was carried out through (SEM). The morphology of the prepared sample is platelet structure and functional group analysis carried out through FT-IR Spectrum. The prepared sample was irradiated through γ-ray CO{sup 60} (100 Gy) was used as γ-ray source. The thermoluminescence glow curve of the irradiated samplemore » showed an isolated peak at around 200°C. The result suggest the prepared nanopowder is suitable for medical radiation dosimetry.« less

Autodisplay for the co-expression of lipase and foldase on the surface of E. coli: washing with designer bugs

PubMed Central

2014-01-01

Background Lipases including the lipase from Burkholderia cepacia are in a main focus in biotechnology research since many years because of their manifold possibilities for application in industrial processes. The application of Burkholderia cepacia lipase for these processes appears complicated because of the need for support by a chaperone, the lipase specific foldase. Purification and reconstitution protocols therefore interfere with an economic implementation of such enzymes in industry. Autodisplay is a convenient method to express a variety of passenger proteins on the surface of E. coli. This method makes subsequent purification steps to obtain the protein of interest unnecessary. If enzymes are used as passengers, the corresponding cells can simply be applied as whole cell biocatalysts. Furthermore, enzymes surface displayed in this manner often acquire stabilization by anchoring within the outer membrane of E. coli. Results The lipase and its chaperone foldase from B. cepacia were co-expressed on the surface of E. coli via autodisplay. The whole cell biocatalyst obtained thereby exhibited an enzymatic activity of 2.73 mU mL-1 towards the substrate p-nitrophenyl palmitate when applied in an OD578 =1. Outer membrane fractions prepared from the same culture volume showed a lipase activity of 4.01 mU mL-1. The lipase-whole cell biocatalyst as well as outer membrane preparations thereof were used in a standardized laundry test, usually adopted to determine the power of washing agents. In this test, the lipase whole cell biocatalyst and the membrane preparation derived thereof exhibited the same lipolytic activity as the purified lipase from B. cepacia and a lipase preparation which is already applied in commercial washing agents. Conclusions Co-expression of both the lipase and its chaperone foldase on the surface of E. coli yields a lipid degrading whole cell biocatalyst. Therefore the chaperone supported folding process, absolutely required for the lipolytic activity appears not to be hindered by surface display. Furthermore, the cells and the membrane preparations appeared to be stable enough to endure a European standard laundry test and show efficient fat removal properties herein. PMID:24476025

Novel Preparation of Calcium Borate/Graphene Oxide Nanocomposites and Their Tribological Properties in Oil

NASA Astrophysics Data System (ADS)

Li, Wei; Cheng, Zhi-Lin; Liu, Zan

2017-01-01

The calcium borate/graphene oxide (CB/GO) nanocomposites have been successfully prepared by a liquid phase-based ultrasonic-assisted stripping method, which were subsequently explored as lubricant additive. The structure and morphology of the as-prepared nanocomposites were characterized by FT-IR, XRD, Raman, TEM, EDS and TGA, revealing that CB nanoparticles were uniformly loaded on GO surfaces. The nanocomposites were highly dispersed into the base oil by sand milling. The tribological properties of CB/GO nanocomposites as lubricating oil additive were investigated using a four-ball machine, and the wear scar surfaces were observed by the 3D Laser Scanning Microscope. The results indicated that CB/GO nanocomposites were of excellent antifriction, antiwear ability and load-carrying capacity.

Synthesis and characterization of high-surface-area millimeter-sized silica beads with hierarchical multi-modal pore structure by the addition of agar

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

Han, Yosep; Choi, Junhyun; Tong, Meiping, E-mail: tongmeiping@iee.pku.edu.cn

2014-04-01

Millimeter-sized spherical silica foams (SSFs) with hierarchical multi-modal pore structure featuring high specific surface area and ordered mesoporous frameworks were successfully prepared using aqueous agar addition, foaming and drop-in-oil processes. The pore-related properties of the prepared spherical silica (SSs) and SSFs were systematically characterized by field emission-scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), small-angle X-ray diffraction (SAXRD), Hg intrusion porosimetry, and N{sub 2} adsorption–desorption isotherm measurements. Improvements in the BET surface area and total pore volume were observed at 504 m{sup 2} g{sup −1} and 5.45 cm{sup 3} g{sup −1}, respectively, after an agar addition and foaming process. Despitemore » the increase in the BET surface area, the mesopore wall thickness and the pore size of the mesopores generated from the block copolymer with agar addition were unchanged based on the SAXRD, TEM, and BJH methods. The SSFs prepared in the present study were confirmed to have improved BET surface area and micropore volume through the agar loading, and to exhibit interconnected 3-dimensional network macropore structure leading to the enhancement of total porosity and BET surface area via the foaming process. - Highlights: • Millimeter-sized spherical silica foams (SSFs) are successfully prepared. • SSFs exhibit high BET surface area and ordered hierarchical pore structure. • Agar addition improves BET surface area and micropore volume of SSFs. • Foaming process generates interconnected 3-D network macropore structure of SSFs.« less

Manganese oxide helices, rings, strands, and films, and methods for their preparation

DOEpatents

Suib, Steven L.; Giraldo, Oscar; Marquez, Manuel; Brock, Stephanie

2003-01-07

Methods for the preparation of mixed-valence manganese oxide compositions with quaternary ammonium ions are described. The compositions self-assemble into helices, rings, and strands without any imposed concentration gradient. These helices, rings, and strands, as well as films having the same composition, undergo rapid ion exchange to replace the quaternary ammonium ions with various metal ions. And the metal-ion-containing manganese oxide compositions so formed can be heat treated to form semi-conducting materials with high surface areas.

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

Ivanov, Ilia N.; Simpson, John T.

A method of preparing a network comprises disposing a solution comprising particulate materials in a solvent onto a superhydrophobic surface comprising a plurality of superhydrophobic features and interfacial areas between the superhydrophobic features. The plurality of superhydrophobic features has a water contact angle of at least about 150.degree.. The method of preparing the network also comprises removing the solvent from the solution of the particulate materials, and forming a network of the particulate materials in the interfacial areas, the particulate materials receding to the interfacial areas as the solvent is removed.

Preparation Methods of Metal Organic Frameworks and Their Capture of CO2

NASA Astrophysics Data System (ADS)

Zhang, Linjian; Liand, Fangqin; Luo, Liangfei

2018-01-01

The increasingly serious greenhouse effect makes people pay more attention to the capture and storage technology of CO2. Metal organic frameworks (MOFs) have the advantages of high specific surface area, porous structure and controllable structure, and become the research focus of CO2 emission reduction technology in recent years. In this paper, the characteristics, preparation methods and application of MOFs in the field of CO2 adsorption and separation are discussed, especially the application of flue gas environment in power plants.

Preparation of ordered mesoporous and macroporous thermoplastic polyurethane surfaces for potential medical applications.

PubMed

Chennell, Philip; Feschet-Chassot, Emmanuelle; Sautou, Valérie; Mailhot-Jensen, Bénédicte

2018-05-01

Thermoplastic polyurethanes are widely used in medical devices. In order to limit some of their shortfalls, like microbial attachment, surfaces modifications can be required. In this work, a two-step replication method was used to create ordered macroporous and mesoporous thermoplastic polyurethane surfaces using anodic aluminum oxide as master template. The intermediate mould materials that were tested were polystyrene and a polyacrylate resin with inorganic filler. All obtained surfaces were characterized by scanning electron microscopy. The initial anodic aluminum oxide surfaces possessed macro or mesopores, function of anodization conditions. The intermediate mould structure correctly replicated the pattern, but the polystyrene surface structures (pillars) were less resistant than the polyacrylate resin ones. The thermoplastic polyurethane pattern possessed macropores or mesopores of about 130 nm or 46 nm diameter and of about 300 nm or 99 nm interpore distances, respectively, in accordance with the initial pattern. Thermoplastic polyurethanes pore depth was however less than initial anodic aluminum oxide pore depth, linked to an incomplete replication during intermediate mould preparation (60 to 90% depth replication). The correct replication of the original pattern confirms that this novel fabrication method is a promising route for surface patterning of thermoplastic polyurethanes that could be used for medical applications.

Preparation and controlled drug delivery applications of mesoporous silica polymer nanocomposites through the visible light induced surface-initiated ATRP

NASA Astrophysics Data System (ADS)

Huang, Long; Liu, Meiying; Mao, Liucheng; Xu, Dazhuang; Wan, Qing; Zeng, Guangjian; Shi, Yingge; Wen, Yuanqing; Zhang, Xiaoyong; Wei, Yen

2017-08-01

The mesoporous materials with large pore size, high specific surface area and high thermal stability have been widely utilized in a variety of fields ranging from environmental remediation to separation and biomedicine. However, surface modification of these silica nanomaterials is required to endow novel properties and achieve better performance for most of these applications. In this work, a new method has been established for surface modification of mesoporous silica nanoparticles (MSNs) that relied on the visible light induced atom transfer radical polymerization (ATRP). In the procedure, the copolymers composited with itaconic acid (IA) and poly(ethylene glycol)methyl acrylate (PEGMA) were grafted from MSNs using IA and PEGMA as the monomers and 10-Phenylphenothiazine(PTH) as the organic catalyst. The successful preparation of final polymer nanocomposites (named as MSNs-NH2-poly(IA-co-PEGMA)) were evidenced by a series of characterization techniques. More importantly, the anticancer agent cisplatin can be effectively loaded on MSNs-NH2-poly(IA-co-PEGMA) and controlled release it from the drug-loading composites with pH responsive behavior. As compared with conventional ATRP, the light induced surface-initiated ATRP could also be utilized for preparation of various silica polymer nanocomposites under rather benign conditions (e.g. absent of transition metal ions, low polymerization temperature and short polymerization time). Taken together, we have developed a rather promising strategy method for fabrication of multifunctional MSNs-NH2-poly(IA-co-PEGMA) with great potential for biomedical applications.

Fabrication of superhydrophobic cotton fabrics using crosslinking polymerization method

NASA Astrophysics Data System (ADS)

Jiang, Bin; Chen, Zhenxing; Sun, Yongli; Yang, Huawei; Zhang, Hongjie; Dou, Haozhen; Zhang, Luhong

2018-05-01

With the aim of removing and recycling oil and organic solvent from water, a facile and low-cost crosslinking polymerization method was first applied on surface modification of cotton fabrics for water/oil separation. Micro-nano hierarchical rough structure was constructed by triethylenetetramine (TETA) and trimesoyl chloride (TMC) that formed a polymeric layer on the surface of the fabric and anchored Al2O3 nanoparticles firmly between the fabric surface and the polymer layer. Superhydrophobic property was further obtained through self-assembly grafting of hydrophobic groups on the rough surface. The as-prepared cotton fabric exhibited superoleophilicity in atmosphere and superhydrophobicity both in atmosphere and under oil with the water contact angle of 153° and 152° respectively. Water/oil separation test showed that the as-prepared cotton fabric can handle with various oil-water mixtures with a high separation efficiency over 99%. More importantly, the separation efficiency remained above 98% over 20 cycles of reusing without losing its superhydrophobicity which demonstrated excellent reusability in oil/water separation process. Moreover, the as-prepared cotton fabric possessed good contamination resistance ability and self-cleaning property. Simulation washing process test showed the superhydrophobic cotton fabric maintained high value of water contact angle above 150° after 100 times washing, indicating great stability and durability. In summary, this work provides a brand-new way to surface modification of cotton fabric and makes it a promising candidate material for oil/water separation.

Surface preparation of substances for continuous convective assembly of fine particles

DOEpatents

Rossi, Robert

2003-01-01

A method for producing periodic nanometer-scale arrays of metal or semiconductor junctions on a clean semiconductor substrate surface is provided comprising the steps of: etching the substrate surface to make it hydrophilic, forming, under an inert atmosphere, a crystalline colloid layer on the substrate surface, depositing a metal or semiconductor material through the colloid layer onto the surface of the substrate, and removing the colloid from the substrate surface. The colloid layer is grown on the clean semiconductor surface by withdrawing the semiconductor substrate from a sol of colloid particles.

A Surface Plasmon Resonance-Based Optical Fiber Probe Fabricated with Electropolymerized Molecular Imprinting Film for Melamine Detection

PubMed Central

Zheng, Yongping; Zhang, Tingwei; Wu, Songjie; Zhang, Jue; Fang, Jing

2018-01-01

Molecularly imprinted polymer (MIP) films prepared by bulk polymerization suffer from numerous deficiencies, including poor mass transfer ability and difficulty in controlling reaction rate and film thickness, which usually result in poor repeatability. However, polymer film synthesized by electropolymerization methods benefit from high reproducibility, simplicity and rapidity of preparation. In the present study, an Au film served as the refractive index-sensitive metal film to couple with the light leaked out from optical fiber core and the electrode for electropolymerizing MIP film simultaneously. The manufactured probe exhibited satisfactory sensitivity and specificity. Furthermore, the surface morphology and functional groups of the synthesized MIP film were characterized by Atomic Force Microscopy (AFM) and Fourier transform infrared microspectroscopy (FTIR) for further insights into the adsorption and desorption processes. Given the low cost, label-free test, simple preparation process and fast response, this method has a potential application to monitor substances in complicated real samples for out-of-lab test in the future. PMID:29522472

Preparation and characteristics of biosilica derived from marine diatom biomass of Nitzschia closterium and Thalassiosira

NASA Astrophysics Data System (ADS)

Qi, Yarong; Wang, Xin; Cheng, Jay Jiayang

2017-05-01

In this study, biosilica of high purity was successfully prepared from marine diatom ( Nitzschia closterium and Thalassiosira) biomass using an optimized novel method with acid washing treatment followed by thermal treatment of the biomass. The optimal condition of the method was 2% diluted HCl washing and baking at 600°C. The SiO2 contents of N. closterium biosilica and Thalassiosira biosilica were 92.23% and 91.52%, respectively, which were both higher than that of diatomite biosilica. The SiO2 morphologies of both biosilica are typical amorphous silica. Besides, N. closterium biosilica possessed micropores and fibers with a surface area of 59.81m2/g. And Thalassiosira biosilica possessed a mesoporous hierarchical skeleton with a surface area of 9.91m2/g. The results suggest that the biosilica samples obtained in this study present highly porous structures. The prepared porous biosilica material possesses great potential to be used as drug delivery carrier, biosensor, biocatalyst as well as adsorbent in the future.

A novel nano-Ni/SiO2 catalyst for hydrogen production from steam reforming of ethanol.

PubMed

Wu, Chunfei; Williams, Paul T

2010-08-01

Catalytic steam reforming of ethanol has been regarded as a promising way to produce hydrogen. However, catalytic deactivation is a key problem in the process. In this paper, a novel nano-Ni/SiO2 catalyst was prepared by a simple sol-gel method and compared to catalysts prepared by an impregnation method in relation to the steam reforming ethanol process. Good Ni dispersion and high BET surface areas (>700 m2 g(-1)) were obtained for sol-gel catalysts, whereas only 1 m2 g(-1) surface area was obtained for the Ni/SiO2 impregnation catalyst. The results of catalytic steam reforming of ethanol showed that about twice of the hydrogen production was produced with the Ni/SiO2 catalyst prepared by sol-gel (around 0.2 g h(-1)) compared with that prepared by impregnation (around 0.1 g h(-1)). The analysis of the used catalysts showed that 10Ni/SiO2-B and 20Ni/SiO2-B presented the highest stability, while other catalysts were fragmented into small pieces after the reforming process, especially the catalysts prepared by impregnation. A novel catalyst has been produced that has been shown to be effective in the production of hydrogen from the steam reforming of ethanol.

Phase quantification by X-ray photoemission valence band analysis applied to mixed phase TiO2 powders

NASA Astrophysics Data System (ADS)

Breeson, Andrew C.; Sankar, Gopinathan; Goh, Gregory K. L.; Palgrave, Robert G.

2017-11-01

A method of quantitative phase analysis using valence band X-ray photoelectron spectra is presented and applied to the analysis of TiO2 anatase-rutile mixtures. The valence band spectra of pure TiO2 polymorphs were measured, and these spectral shapes used to fit valence band spectra from mixed phase samples. Given the surface sensitive nature of the technique, this yields a surface phase fraction. Mixed phase samples were prepared from high and low surface area anatase and rutile powders. In the samples studied here, the surface phase fraction of anatase was found to be linearly correlated with photocatalytic activity of the mixed phase samples, even for samples with very different anatase and rutile surface areas. We apply this method to determine the surface phase fraction of P25 powder. This method may be applied to other systems where a surface phase fraction is an important characteristic.

Evaluation of preparation methods for suspended nano-objects on substrates for dimensional measurements by atomic force microscopy

PubMed Central

Göhler, Daniel; Wessely, Benno; Stintz, Michael; Lazzerini, Giovanni Mattia; Yacoot, Andrew

2017-01-01

Dimensional measurements on nano-objects by atomic force microscopy (AFM) require samples of safely fixed and well individualized particles with a suitable surface-specific particle number on flat and clean substrates. Several known and proven particle preparation methods, i.e., membrane filtration, drying, rinsing, dip coating as well as electrostatic and thermal precipitation, were performed by means of scanning electron microscopy to examine their suitability for preparing samples for dimensional AFM measurements. Different suspensions of nano-objects (with varying material, size and shape) stabilized in aqueous solutions were prepared therefore on different flat substrates. The drop-drying method was found to be the most suitable one for the analysed suspensions, because it does not require expensive dedicated equipment and led to a uniform local distribution of individualized nano-objects. Traceable AFM measurements based on Si and SiO2 coated substrates confirmed the suitability of this technique. PMID:28904839

Evaluation of preparation methods for suspended nano-objects on substrates for dimensional measurements by atomic force microscopy.

PubMed

Fiala, Petra; Göhler, Daniel; Wessely, Benno; Stintz, Michael; Lazzerini, Giovanni Mattia; Yacoot, Andrew

2017-01-01

Dimensional measurements on nano-objects by atomic force microscopy (AFM) require samples of safely fixed and well individualized particles with a suitable surface-specific particle number on flat and clean substrates. Several known and proven particle preparation methods, i.e., membrane filtration, drying, rinsing, dip coating as well as electrostatic and thermal precipitation, were performed by means of scanning electron microscopy to examine their suitability for preparing samples for dimensional AFM measurements. Different suspensions of nano-objects (with varying material, size and shape) stabilized in aqueous solutions were prepared therefore on different flat substrates. The drop-drying method was found to be the most suitable one for the analysed suspensions, because it does not require expensive dedicated equipment and led to a uniform local distribution of individualized nano-objects. Traceable AFM measurements based on Si and SiO 2 coated substrates confirmed the suitability of this technique.

Method of producing nanopatterned articles, and articles produced thereby

DOEpatents

Russell, Thomas P; Park, Soojin; Xu, Ting

2013-11-12

A nanopatterned surface is prepared by forming a block copolymer film on a miscut crystalline substrate, annealing the block copolymer film, then reconstructing the surface of the annealed block copolymer film. The method creates a well-ordered array of voids in the block copolymer film that is maintained over a large area. The nanopatterned block copolymer films can be used ina variety of different applications, including the fabrication of high density data storage media.

Immobilization and functional reconstitution of antibody Fab fragment by solid-phase refolding.

PubMed

Kumada, Yoichi; Hamasaki, Kyoto; Nakagawa, Aya; Sasaki, Eiju; Shirai, Tatsunori; Okumura, Masahiro; Inoue, Manami; Kishimoto, Michimasa

2013-12-31

In this study, we demonstrated the successful preparation of a Fab antibody-immobilized hydrophilic polystyrene (phi-PS) plate via one- and two-step solid-phase refolding methods. Both polystyrene-binding peptide (PS-tag)-fused Fd fragment of heavy chain (Fab H-PS) and full-length of light-chain (Fab L-PS) were individually produced in insoluble fractions of Escherichia coli cells, and they were highly purified in the presence of 8M of urea. Antigen-binding activities of Fab antibody immobilized were correctly recovered by the one-step solid-phase refolding method that a mixture of Fab H-PS and Fab L-PS was immobilized in the presence of 0.5-2M urea, followed by surface washing of the phi-PS plate with PBST. These results indicate that by genetic fusion of a PS-tag, a complex between Fab H and Fab L was efficiently immobilized on the surface of a phi-PS plate even in the presence of a low concentration of urea, and was then correctly refolded to retain its high antigen-binding activity via removal of the urea. A two-step solid-phase refolding method whereby Fab H-PS and Fab L-PS were successively refolded on the surface of a phi-PS plate also resulted in Fab antibody formation on the plate. Furthermore, both the binding affinity and the specificity of the Fab antibody produced by the two-step method were highly maintained, according to the results of sandwich ELISA and competitive ELISA using Fab antibody-immobilized plate via two-step solid-phase refolding. Thus, the solid-phase refolding method demonstrated in this study should be quite useful for the preparation of a Fab antibody-immobilized PS surface with high efficiency from individually produced Fab H-PS and Fab L-PS. This method will be applicable to the preparation of a large Fab antibody library on the surface of a PS plate for use in antibody screening. © 2013. Published by Elsevier B.V. All rights reserved.

Fabrication of a novel superhydrophobic and superoleophilic surface by one-step electrodeposition method for continuous oil/water separation

NASA Astrophysics Data System (ADS)

Xiang, Meisu; Jiang, Meihuizi; Zhang, Yanzong; Liu, Yan; Shen, Fei; Yang, Gang; He, Yan; Wang, Lilin; Zhang, Xiaohong; Deng, Shihuai

2018-03-01

A novel superhydrophobic and superoleophilic surface was fabricated by one-step electrodeposition on stainless steel meshes, and the durability and oil/water separation properties were assessed. Field emission scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), fourier transform infrared spectroscopy (FT-IR) and optical contact angle measurements were used to characterize surface morphologies, chemical compositions, and wettabilities, respectively. The results indicated that the as-prepared mesh preformed excellent superhydrophobicity and superoleophilicity with a high water contact angle (WCA) of 162 ± 1° and oil contact angle of (OCA) 0°. Meanwhile, the as-prepared mesh also exhibited continuous separation capacity of many kinds of oil/water mixtures, and the separation efficiency for lubrication oil/water mixture was about 98.6%. In addition, after 10 separation cycles, the as-prepared mesh possessed the WCAs of 155 ± 2°, the OCAs of 0° and the separation efficiency of 97.8% for lubrication oil/water mixtures. The as-prepared mesh also retained superhydrophobic and superoleophilic properties after abrading, immersing in salt solutions and different pH solutions.

Preparation of MgO/B₂O₃ coatings by plasma spraying on SUS304 surface and effects of heat-resistant.

PubMed

Song, Bo; Zhou, Ningning; Ju, Dongying

2013-12-01

This study mainly deals with the preparation of MgO/B2O3 coatings by plasma spraying on the SUS304 surface and the effects of heat-resistant. The power materials of low thermal conductivity were selected to control the heat divergent performance of high temperature parts. The reticular micro-structure between the cover thermal layer and the substrate was prepared by using the plasma spraying method. The powder mixture of MgO and B2O3 were selected as spraying materials and the SUS304 was used as the substrate material. The MgO/B2O3 coating was prepared on the surface of the SUS304 to provide better cover thermal performance. The properties of the microstructures and the morphologies were studied by Optical Microscope, Scanning Electron Microscope, Electron Probe Microanalyzer, and X-ray Diffraction. The results showed that the cover thermal performance has been improved. Copyright © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Stabilization and Amorphization of Lovastatin Using Different Types of Silica.

PubMed

Khanfar, Mai; Al-Nimry, Suhair

2017-08-01

Lovastatin (LOV), an antihyperlipidimic agent, is characterized by low solubility/poor dissolution and, thus, low bioavailability (<5%). A beneficial effect on its bioavailability could result from improving its dissolution. One of the most common methods used to enhance dissolution is the preparation of solid dispersions. Solid dispersions of LOV and silica with different surface areas were prepared. The effects of the type of silica, ratio of drug/silica, incubation period with silica, and the effect of surface area were all studied. Characterization of the prepared formulae for possible interaction between drug and polymer was carried out using differential scanning calorimetery, Fourier transform infrared spectroscopy, powder X-ray diffraction, surface area determination, and scanning electron microscopy. The dissolution profiles of all prepared formulae were constructed and evaluated. It was found that the formula made of LOV and Sylysia 350 FCP in a ratio of 1:5 after an incubation period of 48 h resulted in the best release, and it was stable after 3 months storage at 75% RH and 40°C.

Conical Tungsten Tips as Substrates for the Preparation of Ultramicroelectrodes

PubMed Central

Hermans, Andre; Wightman, R. Mark

2008-01-01

Here we describe a simple method to prepare voltammetric microelectrodes using tungsten wires as a substrate. Tungsten wires have high tensile modulus and enable the fabrication of electrodes that have small dimensions overall while retaining rigidity. In this work, 125 μm tungsten wires with a conical tip were employed. For the preparation of gold or platinum ultramicroelectrodes, commercial tungsten microelectrodes, completely insulated except at the tip, were used as substrates. Following removal of oxides from the exposed tungsten, platinum or gold was electroplated yielding surfaces with an electroactive area of between 1×10−6 cm2 to 2×10−6 cm2. Carbon surfaces on the etched tip of tungsten microwires were prepared by coating with photoresist followed by pyrolysis. The entire electrode was then insulated with Epoxylite except the tip yielding an exposed carbon surface with an area of around 4×10−6 cm2 to 6×10−6 cm2. All three types of ultramicroelectrodes fabricated on the tungsten wire had similar electrochemical behavior to electrodes fabricated from wires or fibers insulated with glass tubes. PMID:17129002

Application Of Holographic Interferometry For Investigation Of Microroughness Of Engineering Surfaces

NASA Astrophysics Data System (ADS)

Lech, Marek; Mruk, Irena; Stupnicki, Jacek

1985-01-01

The paper describes an improved immersion method of holographic interferometry /IMHI/ adjusted for studies of roughness of engineering surfaces. Special optical arrangement, with two types of immersion cells and adequate technique of preparing transparent replicas reproducting with high fidelity details of differently machined surfaces was elaborated. It permits to obtain the contour maps of the surface asperities with intervals between the planes of succesive contour lines within a range of 1 μm. The results obtained for some engineering surfaces are given.

Investigation of the visible light photocatalytic activity of BiVO4 prepared by sol gel method assisted by ultrasonication.

PubMed

Deebasree, J P; Maheskumar, V; Vidhya, B

2018-07-01

Visible light induced photocatalyst BiVO 4 with monoclinic scheelite structure has been synthesised via sol gel method assisted by ultrasonication. The prepared samples were characterised using X-ray diffraction (XRD), scanning electron microscope (SEM), UV-Vis diffused reflectance spectroscopy (DRS) techniques. The photocatalytic efficiency was evaluated by decolourisation of MB under visible light irradiation. The effect of ultrasound output power on the properties of BiVO 4 during and after preparation by sol-gel method has been compared with normal agitated sample (As prepared). The power of ultrasonic vibration has been varied and an ideal output power which yields better catalytic efficiency is determined. BiVO 4 sonicated with 80 W during preparation 80 W (D) exhibited relatively high surface area, better surface morphology and better catalytic efficiency compared to other samples which were sonicated with 100, 160 and 200 W. The results signify that the photodegradation rate of BiVO 4 80 W (D) sample is high up to 96% in 90 min compared to other samples. Change in morphology leading to better catalytic efficiency was obtained just by exposing the sample to ultrasonic radiation without addition of any surfactant. The recovery test showed that the sample was stable for four consecutive cycles. Using radical test, a reasonable mechanism for photodegradation has been proposed. Copyright © 2018 Elsevier B.V. All rights reserved.

Reporting numeric values of complete crowns. Part 2: Retention and resistance theories.

PubMed

Tiu, Janine; Al-Amleh, Basil; Waddell, J Neil; Duncan, Warwick J

2015-07-01

Determining the retention and resistance of a tooth preparation for a complete crown has only existed in theory, and these theories have never been measured on tooth preparations performed in vivo. The purpose of this study was to measure the theoretical retention and resistance of clinically produced complete crown preparations by using an objective measuring method. Stone dies from 236 complete crown preparations were collected from dental laboratories. The dies were scanned and analyzed with the coordinate geometry method. Cross-sectional images were captured, and the surface area was measured with a cone frustum and right truncated pyramid formula. Two different theories of resistance form, the "on" or "off" theory (limiting taper) and the linear model (resistance length), were calculated for premolar and molar preparations. The mean surface areas ranged from 33.97 mm(2) to 105.44 mm(2) for the cone frustum formula and 41.75 mm(2) to 117.50 mm(2) for the right truncated pyramid formula. The facial side of maxillary premolars exhibited the highest percentage of resistance form with the limiting taper, at 58%, and the mesial side of the mandibular molars exhibited the lowest percentage of resistance form, at 6%. The objective method used in this study provides a way for retention and resistance theories to be tested and for further clinical implications to be investigated. Copyright © 2015 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Shear bond strength of resin composite bonded with two adhesives: Influence of Er: YAG laser irradiation distance

PubMed Central

Shirani, Farzaneh; Birang, Reza; Malekipour, Mohammad Reza; Hourmehr, Zahra; Kazemi, Shantia

2014-01-01

Background: Dental surfaces prepared with different Er:YAG laser distance may have different characteristics compared with those prepared with conventional instruments. The aim of this study was to investigate the effect of Er:YAG laser irradiation distance from enamel and dentin surfaces on the shear bond strength of composite with self-etch and etch and rinse bonding systems compared with conventional preparation method. Materials and Methods: Two hundred caries-free human third molars were randomly divided into twenty groups (n = 10). Ten groups were designated for enamel surface (E1-E10) and ten for dentin surface (D1-D10). Er: YAG laser (2940 nm) was used on the E1-E8 (240 mJ, 25 Hz) and D1-D8 (140 mJ, 30 Hz) groups at four different distances of 0.5 (standard), 2, 4 and 11 mm. Control groups (E9, E10, D9 and D10) were ground with medium grit diamond bur. The enamel and dentin specimens were divided into two subgroups that were bonded with either Single Bond or Clearfil SE Bond. Resin composite (Z100) was dispensed on prepared dentin and enamel. The shear bond strengths were tested using a universal testing machine. Data were analyzed by SPSS12 statistical software using three way analysis of variance, Tukey and independent t-test. P < 0.05 was considered as significant. Results: There was a significant difference between enamel and dentin substrates (P < 0.001) and between lased and un-lased groups; the un-lased group had significantly higher bond strength (P < 0.001). Shear bond strength increased significantly with an increase in the laser irradiation distance (P < 0.05) on enamel surfaces (in both bonding agent subgroups) and on dentin surfaces (in the Single Bond subgroup). Conclusion: Laser irradiation decreases shear bond strength. Irradiation distance affects shear bond strength and increasing the distance would decrease the negative effects of laser irradiation. PMID:25540665

Surface enhanced Raman scattering substrates prepared by thermal evaporation on liquid surfaces.

PubMed

Ye, Ziran; Sun, Guofang; Sui, Chenghua; Yan, Bo; Gao, Fan; Cai, Pinggen; Lv, Bin; Li, Yun; Chen, Naibo; Xu, Fengyun; Wang, Ke; Ye, Gaoxiang; Yang, Shikuan

2018-06-25

We present an effective surface-enhancement Raman scattering(SERS) substrate enabled by depositing metallic film on a liquid surface at room temperature. Thermal evaporation is used to deposit Au atoms on silicone oil surface and then form quasi-continuous films. Due to the isotropic characteristics of the liquid surface, this film consists of substantial nanoparticles with uniform diameter, which is different from films fabricated on solid substrates and can be served as an applicable substrate for SERS detection. With the assistance of this substrate, SERS signals of Rhodamine 6G(R6G) were significantly enhanced, the dependence between SERS spectra and film thickness was investigated. Analytical simulation results confirm the experimental observations and the superiorities of our proposed method for preparation of SERS substrate. This work provides a potential application of metallic film deposition on free-sustained surface and holds promise as an efficient sensor in rapid trace detection of small molecule analytes. © 2018 IOP Publishing Ltd.

Development, validation, and application of a novel LC-MS/MS trace analysis method for the simultaneous quantification of seven iodinated X-ray contrast media and three artificial sweeteners in surface, ground, and drinking water.

PubMed

Ens, Waldemar; Senner, Frank; Gygax, Benjamin; Schlotterbeck, Götz

2014-05-01

A new method for the simultaneous determination of iodated X-ray contrast media (ICM) and artificial sweeteners (AS) by liquid chromatography-tandem mass spectrometry (LC-MS/MS) operated in positive and negative ionization switching mode was developed. The method was validated for surface, ground, and drinking water samples. In order to gain higher sensitivities, a 10-fold sample enrichment step using a Genevac EZ-2 plus centrifugal vacuum evaporator that provided excellent recoveries (90 ± 6 %) was selected for sample preparation. Limits of quantification below 10 ng/L were obtained for all compounds. Furthermore, sample preparation recoveries and matrix effects were investigated thoroughly for all matrix types. Considerable matrix effects were observed in surface water and could be compensated by the use of four stable isotope-labeled internal standards. Due to their persistence, fractions of diatrizoic acid, iopamidol, and acesulfame could pass the whole drinking water production process and were observed also in drinking water. To monitor the fate and occurrence of these compounds, the validated method was applied to samples from different stages of the drinking water production process of the Industrial Works of Basel (IWB). Diatrizoic acid was found as the most persistent compound which was eliminated by just 40 % during the whole drinking water treatment process, followed by iopamidol (80 % elimination) and acesulfame (85 % elimination). All other compounds were completely restrained and/or degraded by the soil and thus were not detected in groundwater. Additionally, a direct injection method without sample preparation achieving 3-20 ng/L limits of quantification was compared to the developed method.

Characterization of Etch Pit Formation via the Everson-Etching Method on CdZnTe Crystal Surfaces from the Bulk to the Nano-Scale

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

Teague, L.; Duff, M.; Cadieux, J.

2010-09-24

A combination of atomic force microscopy, optical microscopy, and mass spectrometry was employed to study CdZnTe crystal surface and used etchant solution following exposure of the CdZnTe crystal to the Everson etch solution. We discuss the results of these studies in relationship to the initial surface preparation methods, the performance of the crystals as radiation spectrometers, the observed etch pit densities, and the chemical mechanism of surface etching. Our results show that the surface features that are exposed to etchants result from interactions with the chemical components of the etchants as well as pre-existing mechanical polishing.

The preparation of Ag-BiVO4 metal composite oxides and its application in efficient photocatalytic oxidative thiophene

NASA Astrophysics Data System (ADS)

Gao, Xiao-Ming; Fu, Feng; Zhang, Li-Ping; Li, Wen-Hong

2013-06-01

A series of Ag-BiVO4 photocatalysts was synthesized by the hydrothemal synthesis method for different pH values. A strong correlation was found among the prepared processing, structure and property of the samples. With increasing pH value from 5 to 9, the crystallinity increases and the as-prepared Ag-BiVO4 sample gradually disappeared from the nanostructures. The light absorption became higher in the UV and visible range, accompanied by a bathochromic shift of the absorption edge. The competitive relations between crystallinity and surface area affecting photocatalytic activity were also discussed. Photocatalytic desulfurization on the as-prepared Ag-BiVO4 samples using thiophene dissolved in n-octane as a model organosulfur compound was performed. It showed that the photocatalytic desulfurization on the as-prepared Ag-BiVO4 sample at pH=7 can be up to 95%, which existed as various size particles and had significant high surface area of 13.768 m2 g-1.

The influence of nanotexturing of poly(lactic-co-glycolic acid) films upon human ovarian cancer cell attachment

NASA Astrophysics Data System (ADS)

Yaşayan, Gökçen; Xue, Xuan; Collier, Pamela; Clarke, Philip; Alexander, Morgan R.; Marlow, Maria

2016-06-01

In this study, we have produced nanotextured poly(lactic-co-glycolic acid) (PLGA) films by using polystyrene (PS) particles as a template to make a polydimethylsiloxane mould against which PLGA is solvent cast. Biocompatible, biodegradable and nanotextured PLGA films were prepared with PS particles of diameter of 57, 99, 210, and 280 nm that produced domes of the same dimension in the PLGA surface. The effect of the particulate monolayer templating method was investigated to enable preparation of the films with uniformly ordered surface nanodomes. Cell attachment of a human ovarian cancer cell line (OVCAR3) alone and co-cultured with mesenchymal stem cells (MSCs) was evaluated on flat and topographically nano-patterned surfaces. Cell numbers were observed to increase on the nanotextured surfaces compared to non-textured surfaces both with OVCAR3 cultures and OVCAR3-MSC co-cultures at 24 and 48 h time points.

Improved perovskite phototransistor prepared using multi-step annealing method

NASA Astrophysics Data System (ADS)

Cao, Mingxuan; Zhang, Yating; Yu, Yu; Yao, Jianquan

2018-02-01

Organic-inorganic hybrid perovskites with good intrinsic physical properties have received substantial interest for solar cell and optoelectronic applications. However, perovskite film always suffers from a low carrier mobility due to its structural imperfection including sharp grain boundaries and pinholes, restricting their device performance and application potential. Here we demonstrate a straightforward strategy based on multi-step annealing process to improve the performance of perovskite photodetector. Annealing temperature and duration greatly affects the surface morphology and optoelectrical properties of perovskites which determines the device property of phototransistor. The perovskite films treated with multi-step annealing method tend to form highly uniform, well-crystallized and high surface coverage perovskite film, which exhibit stronger ultraviolet-visible absorption and photoluminescence spectrum compare to the perovskites prepared by conventional one-step annealing process. The field-effect mobilities of perovskite photodetector treated by one-step direct annealing method shows mobility as 0.121 (0.062) cm2V-1s-1 for holes (electrons), which increases to 1.01 (0.54) cm2V-1s-1 for that treated with muti-step slow annealing method. Moreover, the perovskite phototransistors exhibit a fast photoresponse speed of 78 μs. In general, this work focuses on the influence of annealing methods on perovskite phototransistor, instead of obtains best parameters of it. These findings prove that Multi-step annealing methods is feasible to prepared high performance based photodetector.

Surface Properties and Photocatalytic Activities of the Colloidal ZnS:Mn Nanocrystals Prepared at Various pH Conditions

PubMed Central

Heo, Jungho; Hwang, Cheong-Soo

2015-01-01

Water-dispersible ZnS:Mn nanocrystals (NC) were synthesized by capping the surface with mercaptoacetic acid (MAA) molecules at three different pH conditions. The obtained ZnS:Mn-MAA NC products were physically and optically characterized by corresponding spectroscopic methods. The UV-Visible absorption spectra and PL emission spectra showed broad peaks at 310 and 590 nm, respectively. The average particle sizes measured from the HR-TEM images were 5 nm, which were also supported by the Debye-Scherrer calculations using the X-ray diffraction (XRD) data. Moreover, the surface charges and the degrees of aggregation of the ZnS:Mn-MAA NCs were determined by electrophoretic and hydrodynamic light scattering methods, indicating formation of agglomerates in water with various sizes (50–440 nm) and different surface charge values accordingly the preparation conditions of the NCs (−7.59 to −24.98 mV). Finally, the relative photocatalytic activities of the ZnS:Mn-MAA NCs were evaluated by measuring the degradation rate of methylene blue (MB) molecule in a pseudo first-order reaction condition under the UV-visible light irradiation. As a result, the ZnS:Mn-MAA NC prepared at the pH 7 showed the best photo-degradation efficiency of the MB molecule with the first-order rate constant (kobs) of 2.0 × 10−3·min−1. PMID:28347105

L-Arginine modified multi-walled carbon nanotube/sulfonated poly(ether ether ketone) nanocomposite films for biomedical applications

NASA Astrophysics Data System (ADS)

Kaya, Hatice; Bulut, Osman; Kamali, Ali Reza; Ege, Duygu

2018-06-01

Favorable implant-tissue interactions are crucial to achieve successful osseointegration of the implants. Poly(ether ether ketone) (PEEK) is an interesting alternative to titanium in orthopedics because of its low cost, high biocompatibility and comparable mechanical properties with cancellous bone. Despite these advantages; however, the untreated surface of PEEK fails to osseointegrate due to its bioinert and hydrophobic behavior. This paper deals with the surface modification of PEEK with a novel method. For this, PEEK was first treated with concentrated sulfuric acid to prepare sulfonated PEEK (SPEEK) films using a solvent casting method. Then, 1 and 2 wt% multi-walled carbon nanotube was incorporated into SPEEK to form nanocomposite films. The samples were characterized with Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy. After successful preparation of the nanocomposite films, L-arginine was covalently conjugated on the nanocomposite films to further improve their surface properties. Subsequently, the samples were characterized using X-ray Photoemission Spectroscopy (XPS), water contact angle measurements and Atomic Force Microscopy (AFM) and Dynamic Mechanical Thermal Analysis (DMTA). Finally, cell culture studies were carried out by using Alamar Blue assay to evaluate the biocompatibility of the films. The results obtained indicate the successful preparation of L-arginine-conjugated MWCNT/SPEEK nanocomposite films. The modified surface shows potential to improve implants' mechanical and biological performances.

Oxidation property of SiO2-supported small nickel particle prepared by the sol-gel method

NASA Astrophysics Data System (ADS)

Yamamoto, Y.; Yamashita, S.; Afiza, N.; Katayama, M.; Inada, Y.

2016-05-01

The oxidation property of SiO2-supported small Ni particle has been studied by means of the in-situ XAFS method. The Ni particle with the average diameter of 4 nm supported on SiO2 was prepared by the sol-gel method. The XANES spectrum of the small metallic Ni particle was clearly different from that of bulk Ni. The exposure of diluted O2 gas at room temperature promoted the surface oxidation of Ni(0) particle. During the temperature programmed oxidation process, the supported Ni(0) particle was quantitatively oxidized to NiO, and the oxidation temperature was lower by ca. 200 °C than that of the SiO2-supported Ni particle with the larger particle radius of 17 nm prepared by the impregnation method.

Luminescent systems based on the isolation of conjugated PI systems and edge charge compensation with polar molecules on a charged nanostructured surface

DOEpatents

Ivanov, Ilia N.; Puretzky, Alexander A.; Zhao, Bin; Geohegan, David B.; Styers-Barnett, David J.; Hu, Hui

2014-07-15

A photoluminescent or electroluminescent system and method of making a non-luminescent nanostructured material into such a luminescent system is presented. The method of preparing the luminescent system, generally, comprises the steps of modifying the surface of a nanostructured material to create isolated regions to act as luminescent centers and to create a charge imbalance on the surface; applying more than one polar molecule to the charged surface of the nanostructured material; and orienting the polar molecules to compensate for the charge imbalance on the surface of the nanostructured material. The compensation of the surface charge imbalance by the polar molecules allows the isolated regions to exhibit luminescence.

Cork-resin ablative insulation for complex surfaces and method for applying the same

NASA Technical Reports Server (NTRS)

Walker, H. M.; Sharpe, M. H.; Simpson, W. G. (Inventor)

1980-01-01

A method of applying cork-resin ablative insulation material to complex curved surfaces is disclosed. The material is prepared by mixing finely divided cork with a B-stage curable thermosetting resin, forming the resulting mixture into a block, B-stage curing the resin-containing block, and slicing the block into sheets. The B-stage cured sheet is shaped to conform to the surface being insulated, and further curing is then performed. Curing of the resins only to B-stage before shaping enables application of sheet material to complex curved surfaces and avoids limitations and disadvantages presented in handling of fully cured sheet material.

Correlation between surface morphology and electrical properties of VO2 films grown by direct thermal oxidation method

NASA Astrophysics Data System (ADS)

Yoon, Joonseok; Park, Changwoo; Park, Sungkyun; Mun, Bongjin Simon; Ju, Honglyoul

2015-10-01

We investigate surface morphology and electrical properties of VO2 films fabricated by direct thermal oxidation method. The VO2 film prepared with oxidation temperature at 580 °C exhibits excellent qualities of VO2 characteristics, e.g. a metal-insulator transition (MIT) near 67 °C, a resistivity ratio of ∼2.3 × 104, and a bandgap of 0.7 eV. The analysis of surface morphology with electrical resistivity of VO2 films reveals that the transport properties of VO2 films are closely related to the grain size and surface roughness that vary with oxidation annealing temperatures.

Method of improving field emission characteristics of diamond thin films

DOEpatents

Krauss, A.R.; Gruen, D.M.

1999-05-11

A method of preparing diamond thin films with improved field emission properties is disclosed. The method includes preparing a diamond thin film on a substrate, such as Mo, W, Si and Ni. An atmosphere of hydrogen (molecular or atomic) can be provided above the already deposited film to form absorbed hydrogen to reduce the work function and enhance field emission properties of the diamond film. In addition, hydrogen can be absorbed on intergranular surfaces to enhance electrical conductivity of the diamond film. The treated diamond film can be part of a microtip array in a flat panel display. 3 figs.

Method of improving field emission characteristics of diamond thin films

DOEpatents

Krauss, Alan R.; Gruen, Dieter M.

1999-01-01

A method of preparing diamond thin films with improved field emission properties. The method includes preparing a diamond thin film on a substrate, such as Mo, W, Si and Ni. An atmosphere of hydrogen (molecular or atomic) can be provided above the already deposited film to form absorbed hydrogen to reduce the work function and enhance field emission properties of the diamond film. In addition, hydrogen can be absorbed on intergranular surfaces to enhance electrical conductivity of the diamond film. The treated diamond film can be part of a microtip array in a flat panel display.

40 CFR 53.61 - Test conditions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 5 2010-07-01 2010-07-01 false Test conditions. 53.61 Section 53.61... Equivalent Methods for PM2.5 § 53.61 Test conditions. (a) Sampler surface preparation. Internal surfaces of the candidate sampler shall be cleaned and dried prior to performing any Class II sampler test in this...

40 CFR 53.61 - Test conditions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 5 2011-07-01 2011-07-01 false Test conditions. 53.61 Section 53.61... Equivalent Methods for PM2.5 § 53.61 Test conditions. (a) Sampler surface preparation. Internal surfaces of the candidate sampler shall be cleaned and dried prior to performing any Class II sampler test in this...

Hollow microspheres with a tungsten carbide kernel for PEMFC application.

PubMed

d'Arbigny, Julien Bernard; Taillades, Gilles; Marrony, Mathieu; Jones, Deborah J; Rozière, Jacques

2011-07-28

Tungsten carbide microspheres comprising an outer shell and a compact kernel prepared by a simple hydrothermal method exhibit very high surface area promoting a high dispersion of platinum nanoparticles, and an exceptionally high electrochemically active surface area (EAS) stability compared to the usual Pt/C electrocatalysts used for PEMFC application.

A facile bacterial assisted electrochemical self-assembly of polypyrrole micro-pillars: towards underwater low adhesive superoleophobicity

NASA Astrophysics Data System (ADS)

Cheng, Zhe; Ding, Chunmei; Liu, Huan; Zhu, Ying; Jiang, Lei

2013-12-01

By taking advantage of bacterial extracellular electron transfer behavior, a facile method was developed to fabricate oriented polypyrrole micro-pillars (PPy-MP) with nanoscale surface roughness. Microbes acted as a living conductive template on which PPy was in situ polymerized. The as-prepared PPy-MP exhibit the distinctive underwater low adhesive superoleophobicity which is attributable to the unique hierarchical micro/nano-structures and the high surface energy by doping with inorganic small anions.By taking advantage of bacterial extracellular electron transfer behavior, a facile method was developed to fabricate oriented polypyrrole micro-pillars (PPy-MP) with nanoscale surface roughness. Microbes acted as a living conductive template on which PPy was in situ polymerized. The as-prepared PPy-MP exhibit the distinctive underwater low adhesive superoleophobicity which is attributable to the unique hierarchical micro/nano-structures and the high surface energy by doping with inorganic small anions. Electronic supplementary information (ESI) available: The shape of a water drop on PPy-MPA and cauliflower-like PPy film in air. See DOI: 10.1039/c3nr03788f

Controlling Heteroepitaxy by Oxygen Chemical Potential: Exclusive Growth of (100) Oriented Ceria Nanostructures on Cu(111)

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

Höcker, Jan; Duchoň, Tomáš; Veltruská, Kateřina

2016-01-06

We present a novel and simple method for the preparation of a well-defined CeO 2(100) model system on Cu(111) based on the adjustment of the Ce/O ratio during growth. The method yields micrometer-sized, several nanometers high, single-phase CeO 2(100) islands with controllable size and surface termination that can be benchmarked against the known (111) nanostructured islands on Cu(111). We also demonstrate the ability to adjust the Ce to O stoichiometry from CeO 2(100) (100% Ce 4+) to c-Ce 2O 3(100) (100% Ce 3+), which can be readily recognized by characteristic surface reconstructions observed by low-energy electron diffraction. Finally, the discoverymore » of the highly stable CeO x(100) phase on a hexagonally close packed metal surface represents an unexpected growth mechanism of ceria on Cu(111), and it provides novel opportunities to prepare more elaborate models, benchmark surface chemical reactivity, and thus gain valuable insights into the redox chemistry of ceria in catalytic processes.« less

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.

Preparation, characterization and properties of ZnO nanomaterials

NASA Astrophysics Data System (ADS)

Luo, Jiaolian; Zhang, Xiaoming; Chen, Ruxue; Wang, Xiaohui; Zhu, Ji; Wang, Xiaomin

2017-06-01

In this paper, using the hydrothermal synthesis method, NaOH, Zn(NO3)2, anhydrous ethanol, deionized water as raw material to prepare ZnO nanomaterial, and by X ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL) on the synthesis of nano materials, surface morphology and phase luminescence characterization. The results show that the nano materials synthesized for single-phase ZnO, belonging to the six wurtzite structure; material surface shaped, arranged evenly distributed, and were the top six party structure; ZnO nano materials synthesized with strong emission spectra, emission peak is located at 394nm.

[Optimization of riboflavin sodium phosphate loading to calcium alginate floating microspheres by response surface methodology].

PubMed

Zhang, An-yang; Fan, Tian-yuan

2009-12-18

To investigate the preparation, optimization and in vitro properties of riboflavin sodium phosphate floating microspheres. The floating microspheres composed of riboflavin sodium phosphate and calcium alginate were prepared using ion gelatin-oven drying method. The properties of the microspheres were investigated, including the buoyancy, release, appearance and entrapment efficiency. The formulation was optimized by response surface methodology (RSM). The optimized microspheres were round. The entrapment efficiency was 57.49%. All the microspheres could float on the artificial gastric juice over 8 hours. The release of the drug from the microspheres complied with Fick's diffusion.

Microstructure and magnetism of Co2FeAl Heusler alloy prepared by arc and induction melting compared with planar flow casting

NASA Astrophysics Data System (ADS)

Titov, A.; Jiraskova, Y.; Zivotsky, O.; Bursik, J.; Janickovic, D.

2018-04-01

This paper is devoted to investigations of the structural and magnetic properties of the Co2FeAl Heusler alloy produced by three technologies. The alloys prepared by arc and induction melting have resulted in coarse-grained samples in contrast to the fine-grained ribbon-type sample prepared by planar flow casting. Scanning electron microscopy completed by energy dispersive X-ray spectroscopy, X-ray diffraction, Mössbauer spectroscopy, and magnetic methods sensitive to both bulk and surface were applied. The chemical composition was slightly different from the nominal only for the ribbon sample. From the viewpoint of magnetic properties, the bulk coercivity and remnant magnetization have followed the structure influenced by the technology used. Saturation magnetization was practically the same for samples prepared by arc and induction melting, whereas the magnetization of ribbon is slightly lower due to a higher Al content at the expense of iron and cobalt. The surface magnetic properties were markedly influenced by anisotropy, grain size, and surface roughness of the samples. The surface roughness and brittleness of the ribbon-type sample did not make domain structure observation possible. The other two samples could be well polished and their highly smooth surface has enabled domain structure visualization by both magneto-optical Kerr microscopy and magnetic force microscopy.

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

Investigations on pharmacokinetics and biodistribution of polymeric and solid lipid nanoparticulate systems of atypical antipsychotic drug: effect of material used and surface modification.

PubMed

Joseph, Emil; Saha, Ranendra N

2017-04-01

The present study focuses on the effect of material used for the preparation of nanoparticulate (NP) systems and surface modification on the pharmacokinetics and biodistribution of atypical antipsychotic, olanzapine (OLN). NP carriers of OLN were prepared from two different materials such as polymer (polycaprolactone) and solid lipid (Glyceryl monostearate). These systems were further surface modified with surfactant, Polysorbate 80 and studied for pharmacokinetics-biodistribution in Wistar rats using in-house developed bioanalytical methods. The pharmacokinetics and biodistribution studies resulted in a modified and varied distribution of NP systems with higher area under curve (AUC) values along with prolonged residence time of OLN in the rat blood circulation. The distribution of OLN to the brain was significantly enhanced with surfactant surface-modified NP systems, followed by nonsurface-modified NP formulations as compared with pure OLN solution. Biodistribution study demonstrated a low uptake of obtained NP systems by kidney and heart, thereby decreasing the nephrotoxicity and adverse cardiovascular effects. By coating the NP with surfactant, uptake of macrophage was found to be reduced. Thus, our studies confirmed that the biodistribution OLN could be modified effectively by incorporating in NP drug delivery systems prepared from different materials and surface modifications. A judicious selection of materials used for the preparation of delivery carriers and surface modifications would help to design a most efficient drug delivery system with better therapeutic efficacy.

Method for sealing remote leaks in an enclosure using an aerosol

DOEpatents

Modera, Mark P.; Carrie, Francois R.

1999-01-01

The invention is a method and device for sealing leaks remotely by means of injecting a previously prepared aerosol into the enclosure being sealed according to a particular sealing efficiency defined by the product of a penetration efficiency and a particle deposition efficiency. By using different limits in the relationship between penetration efficiency and flowrate, the same method according the invention can be used for coating the inside of an enclosure. Specifically the invention is a method and device for preparing, transporting, and depositing a solid phase aerosol to the interior surface of the enclosure relating particle size, particle carrier flow rate, and pressure differential, so that particles deposited there can bridge and substantially seal each leak, with out providing a substantial coating at inside surfaces of the enclosure other than the leak. The particle size and flow parameters can be adjusted to coat the interior of the enclosure (duct) without substantial plugging of the leaks depending on how the particle size and flowrate relationships are chosen.

Characterization of ZnO nanoparticles grown in presence of Folic acid template

PubMed Central

2012-01-01

Background ZnO nanoparticles (grown in the template of folic acid) are biologically useful, luminescent material. It can be used for multifunctional purposes, e.g., as biosensor, bioimaging, targeted drug delivery and as growth promoting medicine. Methods Sol–gel chemical method was used to develop the uniform ZnO nanoparticles, in a folic acid template at room temperature and pH ~ 7.5. Agglomeration of the particles was prevented due to surface charge density of folic acid in the medium. ZnO nanoparticle was further characterized by different physical methods. Results Nanocrystalline, wurtzite ZnO particles thus prepared show interesting structural as well as band gap properties due to capping with folic acid. Conclusions A rapid, easy and chemical preparative method for the growth of ZnO nanoparticles with important surface physical properties is discussed. Emphatically, after capping with folic acid, its photoluminescence properties are in the visible region. Therefore, the same can be used for monitoring local environmental properties of biosystems. PMID:22788841

Effect of surface preparation on service life of top-coats applied to weathered primer paint

Treesearch

R. Sam Williams; Mark Knaebe; Peter Sotos

2008-01-01

Paint companies usually recommend that topcoats be applied to primer paint within two weeks. Unfortunately, this is not always possible. For example, onset of winter weather shortly after applying primer may delay topcoat application until spring. Scuff sanding or repriming are often recommended remedial methods for preparing a weathered primer for topcoats, but there...

Processable Aromatic Polyimide Thermoplastic Blends

NASA Technical Reports Server (NTRS)

Baucom, Robert M; Johnston, Norman J.; St. Clair, Terry L.; Nelson, James B.; Gleason, John R.; Proctor, K. Mason

1988-01-01

Method developed for preparing readily-processable thermoplastic polyimides by blending linear, high-molecular-weight, polyimic acid solutions in ether solvents with ultrafine, semicrystalline, thermoplastic polyimide powders. Slurries formed used to make prepregs. Consolidation of prepregs into finsihed composites characterized by excellent melt flow during processing. Applied to film, fiber, fabric, metal, polymer, or composite surfaces. Used to make various stable slurries from which prepregs prepared.

Massachusetts Lowell low speed wind tunnel (LSWT) test section

NASA Astrophysics Data System (ADS)

Anderson, Erik William

The alumina and hybrid alumina-silica FT catalyst were prepared by one-step solgel/oil-drop methods using metal-nitrate-solutions (method-I), and nanoparticle-metaloxides (method-2). The nanoparticle-metal-oxides did not participate in solubility equilibria in contrast to metal nitrate in method-1 causing no metal ion seepage; therefore, method-2 yields higher XRF metal loading efficiency than method-1. The thermal analysis confirmed that the metal loading by method-1 and method-2 involved two different pathways. Method-1 involves solubility equilibria in the conversion of metal-nitrate to metal- hydroxide and finally to metal-oxide, while in method-2 nanoparticle-metal-oxide remained intact during sol-gel-oil-drop and calcination steps. The alumina supported catalysts were dominated by gamma-alumina PXRD peaks in alumina catalysts while amorphous alumino-silicate phase was the bulk of hybrid alumina-silica catalysts. The presence of cobalt oxides (CoO, Co3O4) and iron oxides (FeO, Fe2O3) phases are confirmed in the catalysts prepared by method-1 and method-2. The PXRD analysis indicated weak peak intensities in catalysts with 5 wt. % total metal loading. PXRD pattern confirmed alloy formation in the bimetallic catalysts (CoFe2O4) on alumina support phase gamma-A12 O3. The surface area and pore diameter of hybrid alumina-silica granules (301 - 372 m2/g and 7.3 nm) showed better values than the alumina granules (251 - 256 m2/g and 6.5 nm). The support pore diameter of both types of granules is within the mesoporous range (1 - 50 nm). The morphology of all the catalysts is preserved upon metal loading and heat treatments. The surface characteristics of the sol-gel-oil-drop method prepared catalysts indicate there was no significant pore blockage of the support below 10 wt % total metal loading. The CO conversion of the FT catalysts was measured to screen catalytic active metals and determine the optimum temperatures of the FT reaction for the alumina catalysts. The alumina FT catalysts showed an optimum reaction temperature of 250 °C. Hydrocarbon production and CO conversion of alumina and hybrid alumina-silica FT catalysts were investigated. Among monometallic alumina catalysts, Co(5%) showed a higher CO conversion. The incorporation of Fe to Co increased CO conversion and hydrocarbon production. Increased Fe content in the bimetallic catalysts prepared by combined method-1&2, decreased CO conversion and hydrocarbon production, and increased CO 2 production. The bimetallic nano-Co(2.5%)nano-Fe(2.5%) prepared by method-2 alone showed higher CO conversion comparable to the Co(4%)nano-Fe(l %). Hybrid alumina-silica FT catalysts showed a higher CO conversion than the alumina FT catalysts due to better surface characteristics. The monometallic catalysts showed higher selectivity to C1-C4 hydrocarbon than bimetallic. The bimetallic alumina FT catalysts prepared by method-2 showed slightly higher C5+ selectivity compared to the higher Co catalysts prepared by combined method- I &2. The Ru promotion showed a significant effect on the CO conversion and 11 product distribution of the monometallic catalysts. There was no significant effect on the CO conversion on the (Co-Fe) bimetallic catalysts, but hydrocarbon production slightly increased when promoted by 0.5 wt.% Ru.

Synthesis, characterization, and activity of Co/Fe alumina/silica supported Ft catalysts and the study of promoter effect of ruthenium

NASA Astrophysics Data System (ADS)

Esumike, Sunday Azubike

The alumina and hybrid alumina-silica FT catalyst were prepared by one-step solgel/oil-drop methods using metal-nitrate-solutions (method-I), and nanoparticle-metaloxides (method-2). The nanoparticle-metal-oxides did not participate in solubility equilibria in contrast to metal nitrate in method-1 causing no metal ion seepage; therefore, method-2 yields higher XRF metal loading efficiency than method-1. The thermal analysis confirmed that the metal loading by method-1 and method-2 involved two different pathways. Method-1 involves solubility equilibria in the conversion of metal-nitrate to metal- hydroxide and finally to metal-oxide, while in method-2 nanoparticle-metal-oxide remained intact during sol-gel-oil-drop and calcination steps. The alumina supported catalysts were dominated by gamma-alumina PXRD peaks in alumina catalysts while amorphous alumino-silicate phase was the bulk of hybrid alumina-silica catalysts. The presence of cobalt oxides (CoO, Co3O4) and iron oxides (FeO, Fe2O3) phases are confirmed in the catalysts prepared by method-1 and method-2. The PXRD analysis indicated weak peak intensities in catalysts with 5 wt. % total metal loading. PXRD pattern confirmed alloy formation in the bimetallic catalysts (CoFe2O4) on alumina support phase gamma-A12 O3. The surface area and pore diameter of hybrid alumina-silica granules (301 - 372 m2/g and 7.3 nm) showed better values than the alumina granules (251 - 256 m2/g and 6.5 nm). The support pore diameter of both types of granules is within the mesoporous range (1 - 50 nm). The morphology of all the catalysts is preserved upon metal loading and heat treatments. The surface characteristics of the sol-gel-oil-drop method prepared catalysts indicate there was no significant pore blockage of the support below 10 wt % total metal loading. The CO conversion of the FT catalysts was measured to screen catalytic active metals and determine the optimum temperatures of the FT reaction for the alumina catalysts. The alumina FT catalysts showed an optimum reaction temperature of 250 °C. Hydrocarbon production and CO conversion of alumina and hybrid alumina-silica FT catalysts were investigated. Among monometallic alumina catalysts, Co(5%) showed a higher CO conversion. The incorporation of Fe to Co increased CO conversion and hydrocarbon production. Increased Fe content in the bimetallic catalysts prepared by combined method-1&2, decreased CO conversion and hydrocarbon production, and increased CO 2 production. The bimetallic nano-Co(2.5%)nano-Fe(2.5%) prepared by method-2 alone showed higher CO conversion comparable to the Co(4%)nano-Fe(l %). Hybrid alumina-silica FT catalysts showed a higher CO conversion than the alumina FT catalysts due to better surface characteristics. The monometallic catalysts showed higher selectivity to C1-C4 hydrocarbon than bimetallic. The bimetallic alumina FT catalysts prepared by method-2 showed slightly higher C5+ selectivity compared to the higher Co catalysts prepared by combined method- I &2. The Ru promotion showed a significant effect on the CO conversion and 11 product distribution of the monometallic catalysts. There was no significant effect on the CO conversion on the (Co-Fe) bimetallic catalysts, but hydrocarbon production slightly increased when promoted by 0.5 wt.% Ru.

Fabrication and condensation characteristics of metallic superhydrophobic surface with hierarchical micro-nano structures

NASA Astrophysics Data System (ADS)

Chu, Fuqiang; Wu, Xiaomin

2016-05-01

Metallic superhydrophobic surfaces have various applications in aerospace, refrigeration and other engineering fields due to their excellent water repellent characteristics. This study considers a simple but widely applicable fabrication method using a two simultaneous chemical reactions method to prepare the acid-salt mixed solutions to process the metal surfaces with surface deposition and surface etching to construct hierarchical micro-nano structures on the surface and then modify the surface with low surface-energy materials. Al-based and Cu-based superhydrophobic surfaces were fabricated using this method. The Al-based superhydrophobic surface had a water contact angle of 164° with hierarchical micro-nano structures similar to the lotus leaves. The Cu-based surface had a water contact angle of 157° with moss-like hierarchical micro-nano structures. Droplet condensation experiments were also performed on these two superhydrophobic surfaces to investigate their condensation characteristics. The results show that the Al-based superhydrophobic surface has lower droplet density, higher droplet jumping probability, slower droplet growth rate and lower surface coverage due to the more structured hierarchical structures.

Machine for preparing phosphors for the fluorimetric determination of uranium

USGS Publications Warehouse

Stevens, R.E.; Wood, W.H.; Goetz, K.G.; Horr, C.A.

1956-01-01

The time saved by use of a machine for preparing many phosphors at one time increases the rate of productivity of the fluorimetric method for determining uranium. The machine prepares 18 phosphors at a time and eliminates the tedious and time-consuming step of preparing them by hand, while improving the precision of the method in some localities. The machine consists of a ring burner over which the platinum dishes, containing uranium and flux, are rotated. By placing the machine in an inclined position the molten flux comes into contact with all surfaces within th dish as the dishes rotate over the flame. Precision is improved because the heating and cooling conditions are the same for each of the 18 phosphors in one run as well as for successive runs.

Directed spatial organization of zinc oxide nanostructures

DOEpatents

Hsu, Julia [Albuquerque, NM; Liu, Jun [Richland, WA

2009-02-17

A method for controllably forming zinc oxide nanostructures on a surface via an organic template, which is formed using a stamp prepared from pre-defined relief structures, inking the stamp with a solution comprising self-assembled monolayer (SAM) molecules, contacting the stamp to the surface, such as Ag sputtered on Si, and immersing the surface with the patterned SAM molecules with a zinc-containing solution with pH control to form zinc oxide nanostructures on the bare Ag surface.

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.

Raman study of TiO2 coatings modified by UV pulsed laser

NASA Astrophysics Data System (ADS)

Belka, Radosław; Keczkowska, Justyna; Sek, Piotr

2016-12-01

The TiO2 coatings were prepared by simple sol-gel method and modified by UV pulsed laser. TiO2, also know as titania, is a ceramic compound, existing in numerous polymorphic forms, mainly as tetragonal rutile and anatase, and rhomboidal brookite. Rutile is the most stable form of titanium dioxide, whereas anatase is a metastable form, created in lower temperatures than rutile. Anatase is marked with higher specific surface area, porosity and a higher number of surface hydroxyl groups as compared to rutile. The unique optical and electronic properties of TiO2 results in its use as semiconductors dielectric mirrors, sunscreen and UV-blocking pigments and especially as photocatalyst. In this paper, the tetraisopropoxide was used as Ti precursor according to sol-gel method. An organic base was applied during sol preparation. Prepared gel was coated on glass substrates and calcined in low temperature to obtain amorphous phase of titania. Prepared coatings were modified by UV picosecond pulse laser with different pulse repetition rate and pulse power. Physical modification of the coatings using laser pulses was intended in order change the phase content of the produced material. Raman spectroscopy (RS) method was applied to studies of modified coatings as it is one of the basic analytical techniques, supporting the identification of compounds and obtaining information about the structure. Especially, RS is a useful method for distinguishing the anatase and rutile phases. In these studies, anatase to rutile transformation was observed, depending on laser parameters.

Studies on stabilization mechanism and stealth effect of poloxamer 188 onto PLGA nanoparticles.

PubMed

Jain, Darshana; Athawale, Rajani; Bajaj, Amrita; Shrikhande, Shruti; Goel, Peeyush N; Gude, Rajiv P

2013-09-01

In nanoparticulate engineering for drug delivery systems, poloxamers tri block copolymers are employed as adsorbing molecules to modify the aggregation state and impart stability to products. The aim was to prepare nanoparticles using poloxamer188 as stabiliser and investigate the mechanism of stabilisation of the prepared particles. Nanoparticles were prepared by solvent diffusion method with poloxamer 188 as stabiliser. Hydrodynamic thickness and zeta potential of the prepared nanoparticles were determined by photon correlation spectroscopy. To study the extent of adsorption of poloxamer onto the prepared nanoparticles, adsorption isotherms were constructed. The adsorbed amount of poloxamer 188 onto the particles was determined by depletion method. Macrophageal uptake study was performed to assess the uptake of the prepared nanoparticles using RAW 264.7 cell lines. Nanoparticles were prepared with slight increase in particle size and in absolute value of zeta potential compared to uncoated particles suggesting that this effect was due to adsorption of poloxamer 188. TEM studies and surface area analysis supported the results obtained from particle size analysis indicating preparation of particles with a thin layer of adsorbed poloxamer 188. Adsorption kinetics modeling suggested that at low concentrations (0.001-0.010 g/L), Langmuir monolayer equation fits quite well and at higher concentrations (above 0.010 g/L) multilayer adsorption of poloxamer 188 onto the prepared particles occurred. Thus the nanoparticles had multilayer of poloxamer 188 adsorbed onto the non uniform surface of PLGA. Results of macrophageal uptake and liver cell study exhibits adsorbed concentration dependent bypass of RES uptake of nanoparticles. Hence, results substantiate the application of adsorption isotherms for designing nanoparticles possessing potential to exhibit prolonged circulation when administered in vivo. Copyright © 2013 Elsevier B.V. All rights reserved.

Robust superhydrophobic surface by nature-inspired polyphenol chemistry for effective oil-water separation

NASA Astrophysics Data System (ADS)

Bu, Yiming; Huang, Jingjing; Zhang, Shiyu; Wang, Yinghua; Gu, Shaojin; Cao, Genyang; Yang, Hongjun; Ye, Dezhan; Zhou, Yingshan; Xu, Weilin

2018-05-01

With the ever-increasing oil spillages, oil-water separation has attracted widespread concern in recent years. In this work, a nature-inspired polyphenol method has been developed to fabricate the durable superhydrophobic surfaces for the oil-water separation. Inspiring from the adhesion of polyphenol and reducing capacity of free catechol/pyrogallol groups in polyphenol, firstly, the simple immersion of commercial materials (melamine sponge, PET, and nonwoven cotton fabrics) in tannic acid (TA) solution allows to form a multifunctional coating on the surface of sponge or fabrics, which was used as reducing reagent to generate Ag nanoparticles (NPs). Then, decoration of 1H, 1H, 2H, 2H-perfluorodecanethiol (PFDT) molecules produced superhydrophobic surfaces. The surface topological structure, chemical composition, and superhydrophobic property of the as-prepared surface are characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDS), and water contact angle (WCA) measurements. The WCAs of as-prepared sponge and fabrics were higher than 150°. The stability, absorption capacity, and recyclability of as-prepared sponge and fabrics were investigated. The as-prepared sponge demonstrates high oil/water selectivity and high absorption capacity (66-150 g/g) for a broad variety of oils and organic solvents, and was chemically resistant, robust against abrasion, and long-term durability in harsh environments. Most important of all, it can continuously separate various kinds of oils or organic pollutants from the surface of water. This study presents a facile strategy to fabricate superhydrophobic materials for continuous oil-water separation, displaying great potential in large-scale practical application.

Two-step fabrication of ZnO-PVP composites with tunable visible emissions

NASA Astrophysics Data System (ADS)

Agulto, Verdad C.; Empizo, Melvin John F.; Kawano, Keisuke; Minami, Yuki; Yamanoi, Kohei; Sarukura, Nobuhiko; Yago, Allan Christopher C.; Sarmago, Roland V.

2018-02-01

We report a two-step fabrication of zinc oxide-polyvinylpyrrolidone (ZnO-PVP) composites for potential phosphor-based applications. The composites are fabricated by initially preparing ZnO microrods using hydrothermal growth method and then dip-coating the microrods into aqueous PVP solutions with varying molar concentrations. The as-prepared ZnO microrods exhibit smooth surfaces and broad visible emissions, while the ZnO-PVP composites have pitted surfaces with shifted and reduced visible emissions. These changes in the structural and optical properties, which are found to depend on the PVP concentration, are attributed to the adsorption of PVP on the microrod surface. Although the surface morphology and visible emission are modified by PVP, the composites still maintain a hexagonal wurtzite crystal structure and near-band-edge ultraviolet (UV) emission similar with the as-prepared microrods. Our results therefore suggest that the ZnO-PVP composites can be used as phosphors that offer not only properties found in both ZnO and PVP but also tunable visible emissions which can be controlled during material fabrication.

Preparation of TNT, RDX and Ammonium Nitrate Standards on Gold-on-Silicon Surfaces by Thermal Inkjet Technology

NASA Astrophysics Data System (ADS)

Wrable-Rose, Madeline; Primera-Pedrozo, Oliva M.; Pacheco-Londoño, Leonardo C.; Hernandez-Rivera, Samuel P.

2010-12-01

This research examines the surface contamination properties, trace sample preparation methodologies, detection systems response and generation of explosive contamination standards for trace detection systems. Homogeneous and reproducible sample preparation is relevant for trace detection of chemical threats, such as warfare agents, highly energetic materials (HEM) and toxic industrial chemicals. The objective of this research was to develop a technology capable of producing samples and standards of HEM with controlled size and distribution on a substrate to generate specimens that would reproduce real contamination conditions. The research activities included (1) a study of the properties of particles generated by two deposition techniques: sample smearing deposition and inkjet deposition, on gold-coated silicon, glass and stainless steel substrates; (2) characterization of composition, distribution and adhesion characteristics of deposits; (3) evaluation of accuracy and reproducibility for depositing neat highly energetic materials such as TNT, RDX and ammonium nitrate; (4) a study of HEM-surface interactions using FTIR-RAIRS; and (5) establishment of protocols for validation of surface concentration using destructive methods such as HPLC.

Efficient Preparation of Super Antifouling PVDF Ultrafiltration Membrane with One Step Fabricated Zwitterionic Surface.

PubMed

Zhao, Xinzhen; He, Chunju

2015-08-19

On the basis of the excellent fouling resistance of zwitterionic materials, the super antifouling polyvinylidene fluoride (PVDF) membrane was efficiently prepared though one-step sulfonation of PVDF and polyaniline blend membrane in situ. The self-doped sulfonated polyaniline (SPANI) was generated as a novel zwitterionic polymer to improve the antifouling property of PVDF ultrafiltration membrane used in sewage treatment. Surface attenuated total reflection Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, surface zeta potential, and water contact angle demonstrated the successful fabrication of zwitterionic interface by convenient sulfonation modification. The static adsorption fouling test showed the quantified adsorption mass of bovine serum albumin (BSA) pollutant on the PVDF/SPANI membrane surface decreases to 3(±2) μg/cm(2), and the water flux recovery ratio (FRR) values were no less than 95% for the three model pollutants of BSA, sodium alginate (SA), and humic acid (HA), which were corresponding hydrophobic, hydrophilic, and natural pollutants in sewage, respectively. This Research Article demonstrated the antifouling advantages of zwitterionic SPANI and aimed to provide a simple method for the large scale preparation of zwitterionic antifouling ultrafiltration membranes.

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.

Enhancement of solar hydrogen evolution from water by surface modification with CdS and TiO2 on porous CuInS2 photocathodes prepared by an electrodeposition-sulfurization method.

PubMed

Zhao, Jiao; Minegishi, Tsutomu; Zhang, Li; Zhong, Miao; Gunawan; Nakabayashi, Mamiko; Ma, Guijun; Hisatomi, Takashi; Katayama, Masao; Ikeda, Shigeru; Shibata, Naoya; Yamada, Taro; Domen, Kazunari

2014-10-27

Porous films of p-type CuInS2, prepared by sulfurization of electrodeposited metals, are surface-modified with thin layers of CdS and TiO2. This specific porous electrode evolved H2 from photoelectrochemical water reduction under simulated sunlight. Modification with thin n-type CdS and TiO2 layers significantly increased the cathodic photocurrent and onset potential through the formation of a p-n junction on the surface. The modified photocathodes showed a relatively high efficiency and stable H2 production under the present reaction conditions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Measurement of surface contamination by certain antineoplastic drugs using high-performance liquid chromatography: applications in occupational hygiene investigations in hospital environments.

PubMed

Rubino, F M; Floridia, L; Pietropaolo, A M; Tavazzani, M; Colombi, A

1999-01-01

Within the context of continuing interest in occupational hygiene of hospitals as workplaces, the authors report the results of a preliminary study on surface contamination by certain antineoplastic drugs (ANDs), recently performed in eight cancer departments of two large general hospitals in Milan, Italy. Since reliable quantitative information on the exposure levels to individual drugs is mandatory to establish a strong interpretative framework for correctly assessing the health risks associated with manipulation of ANDs and rationally advise intervention priorities for exposure abatement, two automated analytical methods were set up using reverse-phase high-performance liquid chromatography for the measurement of contamination by 1) methotrexate (MTX) and 2) the three most important nucleoside analogue antineoplastic drugs (5-fluorouracil 5FU, Cytarabin CYA, Gemcytabin GCA) on surfaces such as those of preparation hoods and work-benches in the pharmacies of cancer wards. The methods are characterized by short analysis time (7 min) under isocratic conditions, by the use of a mobile phase with a minimal content of organic solvent and by high sensitivity, adequate to detect surface contamination in the 5-10 micrograms/m2 range. To exemplify the performance of the analytical methods in the assessment of contamination levels from the target analyte ANDs, data are reported on the contamination levels measured on various surfaces (such as on handles, floor surfaces and window panes, even far from the preparation hood). Analyte concentrations corresponding to 0.8-1.5 micrograms of 5FU were measured on telephones, 0.85-28 micrograms/m2 of CYA were measured on tables, 1.2-1150 micrograms/m2 of GCA on furniture and floors. Spillage fractions between 1-5% of the used ANDs (daily use 5FU 7-13 g; CYA 0.1-7.1 g; GCA 0.2-5 g) were measured on the disposable polythene-backed paper cover sheet of the preparation hood.

Surface Relief of Mapping

NASA Astrophysics Data System (ADS)

Costa, Manuel F.; Almeida, Jose B.

1989-02-01

We will describe in this communication a noncont act method of measuring surface profile, it does not require any surface preparation, and it can be used with a very large range of surfaces from highly reflecting to non reflecting ones and as complex as textile surfaces. This method is reasonably immune to dispersion and diffraction, which usually make very difficult the application of non contact profilometry methods to a wide range of materials and situations, namely on quality control systems in industrial production lines. The method is based on the horizontal shift of the bright spot on a horizontal surface when this is illuminated with an oblique beam and moved vertically. in order to make the profilometry the sample is swept by an oblique light beam and the bright spot position is compared with a reference position. The bright spot must be as small as possible, particularly in very irregular surfaces; so the light beam diameter must be as small as possible and the incidence angle must not be too small. The sensivity of a system based on this method will be given, mostly, by the reception optical system.

Adjustment of surface chemical and physical properties with functionalized polymers to control cell adhesion

NASA Astrophysics Data System (ADS)

Zhou, Zhaoli

Cell-surface interaction is crucial in many cellular functions such as movement, growth, differentiation, proliferation and survival. In the present work, we have developed several strategies to design and prepare synthetic polymeric materials with selected cues to control cell attachment. To promote neuronal cell adhesion on the surfaces, biocompatible, non-adhesive PEG-based materials were modified with neurotransmitter acetylcholine functionalities to produce hydrogels with a range of porous structures, swollen states, and mechanical strengths. Mice hippocampal cells cultured on the hydrogels showed differences in number, length of processes and exhibited different survival rates, thereby highlighting the importance of chemical composition and structure in biomaterials. Similar strategies were used to prepare polymer brushes to assess how topographical cues influence neuronal cell behaviors. The brushes were prepared using the "grown from" method through surface-initiated atom transfer radical polymerization (SI-ATRP) reactions and further patterned via UV photolithography. Protein absorption tests and hippocampal neuronal cell culture of the brush patterns showed that both protein and neuronal cells can adhere to the patterns and therefore can be guided by the patterns at certain length scales. We also prepared functional polymers to discourage attachment of undesirable cells on the surfaces. For example, we synthesized PEG-perfluorinated alkyl amphiphilic surfactants to modify polystyrene-block-poly(ethylene-ran-butylene)- block-polyisoprene (SEBI or K3) triblock copolymers for marine antifouling/fouling release surface coatings. Initial results showed that the polymer coated surfaces can facilitate removal of Ulva sporelings on the surfaces. In addition, we prepared both bioactive and dual functional biopassive/bioactive antimicrobial coatings based on SEBI polymers. Incubating the polymer coated surfaces with gram-positive bacteria (S. aureus), gram-negative bacteria (E. coli) and marine bacteria (C. marina ) species demonstrated that, unlike biopassive surfaces, the dual functionality polymer coated surfaces can significantly reduce both live and dead cells, without killing the cells in the culture media. The knowledge gained from those studies offers opportunities for further modification and potential applications of those types of polymers in the future.

Method of producing nanopatterned articles, and articles produced thereby

DOEpatents

Russell, Thomas P; Park, Soojin; Xu, Ting

2015-04-28

A nanopatterned surface is prepared by forming a block copolymer film on a miscut crystalline substrate, annealing the block copolymer film, then reconstructing the surface of the annealed block copolymer film The method creates a well-ordered array of voids in the block copolymer film that is maintained over a large area. The nanopatterned block copolymer films can be used in a variety of different applications, including the fabrication of high density data storage media.

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

Fabrication of porous low crystalline calcite block by carbonation of calcium hydroxide compact.

PubMed

Matsuya, Shigeki; Lin, Xin; Udoh, Koh-ichi; Nakagawa, Masaharu; Shimogoryo, Ryoji; Terada, Yoshihiro; Ishikawa, Kunio

2007-07-01

Calcium carbonate (CaCO(3)) has been widely used as a bone substitute material because of its excellent tissue response and good resorbability. In this experimental study, we propose a new method obtaining porous CaCO(3) monolith for an artificial bone substitute. In the method, calcium hydroxide compacts were exposed to carbon dioxide saturated with water vapor at room temperature. Carbonation completed within 3 days and calcite was the only product. The mechanical strength of CaCO(3) monolith increased with carbonation period and molding pressure. Development of mechanical strength proceeded through two steps; the first rapid increase by bonding with calcite layer formed at the surface of calcium hydroxide particles and the latter increase by the full conversion of calcium hydroxide to calcite. The latter process was thought to be controlled by the diffusion of CO(2) through micropores in the surface calcite layer. Porosity of calcite blocks thus prepared had 36.8-48.1% depending on molding pressure between 1 MPa and 5 MPa. We concluded that the present method may be useful for the preparation of bone substitutes or the preparation of source material for bone substitutes since this method succeeded in fabricating a low-crystalline, and thus a highly reactive, porous calcite block.

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.

A new carbon-based magnetic material for the dispersive solid-phase extraction of UV filters from water samples before liquid chromatography-tandem mass spectrometry analysis.

PubMed

Piovesana, Susy; Capriotti, Anna Laura; Cavaliere, Chiara; La Barbera, Giorgia; Samperi, Roberto; Zenezini Chiozzi, Riccardo; Laganà, Aldo

2017-07-01

Magnetic solid-phase extraction is one of the most promising new extraction methods for liquid samples before ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis. Several types of materials, including carbonaceous ones, have been prepared for this purpose. In this paper, for the first time, the preparation, characterization, and sorption capability of Fe 3 O 4 -graphitized carbon black (mGCB) composite toward some compounds of environmental interest were investigated. The synthesized mGCB consisted of micrometric GCB particles with 55 m 2  g -1 surface area bearing some carbonyl and hydroxyl functionalities and the surface partially decorated by Fe 3 O 4 microparticles. The prepared mGCB was firstly tested as an adsorbent for the extraction from surface water of 50 pollutants, including estrogens, perfluoroalkyl compounds, UV filters, and quinolones. The material showed good affinity to many of the tested compounds, except carboxylates and glucoronates; however, some compounds were difficult to desorb. Ten UV filters belonging to the chemical classes of benzophenones and p-aminobenzoates were selected, and parameters were optimized for the extraction of these compounds from surface water before UHPLC-MS/MS determination. Then, the method was validated in terms of linearity, trueness, intra-laboratory precision, and detection and quantification limits. In summary, the method performance (trueness, expressed as analytical recovery, 85-114%; RSD 5-15%) appears suitable for the determination of the selected compounds at the level of 10-100 ng L -1 , with detection limits in the range of 1-5 ng L -1 . Finally, the new method was compared with a published one, based on conventional solid-phase extraction with GCB, showing similar performance in real sample analysis. Graphical Abstract Workflow of the analytical method based on magnetic solid-phase extraction followed by LC-MS/MS determination.

Effects of surface morphology of ZnO seed layers on growth of ZnO nanostructures prepared by hydrothermal method and annealing.

PubMed

Yim, Kwang Gug; Kim, Min Su; Leem, Jae-Young

2013-05-01

ZnO nanostructures were grown on Si (111) substrates by a hydrothermal method. Prior to growing the ZnO nanostructures, ZnO seed layers with different post-heat temperatures were prepared by a spin-coating process. Then, the ZnO nanostructures were annealed at 500 degrees C for 20 min under an Ar atmosphere. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and photoluminescence (PL) were carried out at room temperature (RT) to investigate the structural and optical properties of the as-grown and annealed ZnO nanostructures. The surface morphologies of the seed layers changed from a smooth surface to a mountain chain-like structure as the post-heating temperatures increased. The as-grown and annealed ZnO nanostructures exhibited a strong (002) diffraction peak. Compared to the as-grown ZnO nanostructures, the annealed ZnO nanostructures exhibited significantly strong enhancement in the PL intensity ratio by almost a factor of 2.

Optical enhancement of Au doped ZrO2 thin films by sol-gel dip coating method

NASA Astrophysics Data System (ADS)

John Berlin, I.; Joy, K.

2015-01-01

Homogeneous and transparent Au doped ZrO2 thin films were prepared by sol-gel dip coating method. The films have mixed phase of tetragonal, monoclinic and face centered cubic with crack free surface. Due to the increase in Au doping concentration many-body interaction occurs between free carriers and ionized impurities causing decrease in optical band gap from 5.72 to 5.40 eV. Localized surface plasmon resonance peak of the Au doped films appeared at 610 nm. Conversion of photons to surface plasmons allows the sub-wavelength manipulation of electromagnetic radiation. Hence the prepared Au doped ZrO2 thin films can be applied in nanoscale photonic devices such as lenses, switches, waveguides etc. Moreover the photoluminescence (PL) intensity of Au doped ZrO2 thin films decrease due to decrease in the radiative recombination, life time of the excitons and suppression of grain growth of ZrO2 with increasing Au dopant.

Catalytic properties of mesoporous Al–La–Mn oxides prepared via spray pyrolysis

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

Kim, Goun; Jung, Kyeong Youl; Lee, Choul-Ho

Highlights: • Al–La–Mn oxides were prepared using spray pyrolysis. • Al–La–Mn oxides exhibit large and uniform pore sizes. • Mesoporous Al–La–Mn oxides were compared with those prepared by conventional precipitation. • Mesoporous Al–La–Mn oxides show superior activity in decomposition of hydrogen peroxide. - Abstract: Mesoporous Al–La–Mn oxides are prepared via spray pyrolysis and are applied to the catalytic decomposition of hydrogen peroxide. The characteristics of the mesoporous Al–La–Mn oxides are examined using N{sub 2} adsorption, X-ray diffraction, and X-ray fluorescence measurements. The surface area and pore size of the Al–La–Mn oxides prepared via spray pyrolysis are larger than those ofmore » the Al–La–Mn oxides prepared using a precipitation method. The catalytic performance of the materials during the decomposition of hydrogen peroxide is examined in a pulse-injection reactor. It is confirmed that the mesoporous Al–La–Mn oxides prepared via spray pyrolysis exhibit higher catalytic activity and stability in the decomposition of hydrogen peroxide than Al–La–Mn oxides prepared using a conventional precipitation method.« less

A facile method to prepare "green" nano-phosphors with a large Stokes-shift and solid-state enhanced photophysical properties based on surface-modified gold nanoclusters.

PubMed

Cheng, C H; Huang, H Y; Talite, M J; Chou, W C; Yeh, J M; Yuan, C T

2017-12-15

Colloidal nano-materials, such as quantum dots (QDs) have been applied to light-conversion nano-phosphors due to their unique tunable emission. However, most of the QDs involve toxic elements and are synthesized in a hazardous solvent. In addition, conventional QD nano-phosphors with a small Stokes shift suffered from reabsorption losses and aggregation-induced quenching in the solid state. Here, we demonstrate a facile, matrix-free method to prepare eco-friendly nano-phosphors with a large Stokes shift based on aqueous thiolate-stabilized gold nanoclusters (GSH-AuNCs) with simple surface modifications. Our method is just to drop GSH-AuNCs solution on the aluminum foil and then surface-modified AuNCs (Al-GSH-AuNCs) can be spontaneously precipitated out of the aqueous solution. Compared with pristine GSH-AuNCs in solution, the Al-GSH-AuNCs exhibit enhanced solid-state PL quantum yields, lengthened PL lifetime, and spectral blue shift, which can be attributed to the aggregation-induced emission enhancement facilitated by surface modifications. Such surface-treatment induced aggregation of AuNCs can restrict the surface-ligand motion, leading to the enhancement of PL properties in the solid state. In addition, the Al-GSH-AuNCs nano-phosphors with a large Stokes shift can mitigate the aggregation-induced PL quenching and reabsorption losses, which would be potential candidates for "green" nano-phosphors. Copyright © 2017 Elsevier Inc. All rights reserved.

Monodispersed ZIF-8 particles with enhanced performance for CO2 adsorption and heterogeneous catalysis

NASA Astrophysics Data System (ADS)

Guan, Yebin; Shi, Juanjuan; Xia, Ming; Zhang, Jun; Pang, Zhenfeng; Marchetti, Alessandro; Wang, Xiaohong; Cai, Jingsong; Kong, Xueqian

2017-11-01

Monodispersed zeolitic imidazolate frameworks (ZIFs) were prepared with a simple method using dimethylsulfoxide (DMSO) as solvent. This method yields ZIF-8 nanoparticles with a narrow particle size distribution of 90-110 nm and the dispersion is highly stable against agglomeration. These particles have larger nanosized porosity and enhanced CO2 adsorption capability compared to ZIF-8 prepared with different solvents such as methanol or N, N-dimethyl formamide. Their uniform size and surface chemistry also lead to superior performance in the Knoevenagel condensation reactions. The ZIF-8 nanoparticles possess high thermal stability up to 550 °C and the preparation steps are easy for scaling up which are favorable for industrial applications.

Sum frequency generation spectroscopy study of hydrogenated stepped Si(111) surfaces made by molecular hydrogen exposure

NASA Astrophysics Data System (ADS)

Hien, K. T. T.; Sattar, M. A.; Miyauchi, Y.; Mizutani, G.; Rutt, H. N.

2017-09-01

Hydrogen adsorption on stepped Si(111) surfaces 9.5° miscut in the [ 1 ̅ 1 ̅ 2 ] direction has been investigated in situ in a UHV chamber with a base pressure of 10-8 Pa. The H-Si(111)1×1 surface was prepared by exposing the wafer to ultra-pure hydrogen gas at a pressure of 470 Pa. Termination of hydrogen on terraces and steps was observed by sum frequency generation (SFG) with several polarization combinations such as ppp, ssp, pps, spp, psp, sps, pss and sss. Here the 1st, 2nd and 3rd symbols indicate SFG, visible and IR polarizations, respectively. ppp and ssp-SFG clearly showed only two modes: the Si-H stretching vibration terrace mode at 2082 cm-1 (A) and the vertical step dihydride vibration mode at 2094 cm-1 (C1). Interesting points are the appearance of the C1 mode in contrast to the previous SFG spectrum of the H-Si(111)1×1 surface with the same miscut surface angle prepared by wet chemical etching. We suggest that the formation of step dihydride and its orientation on the Si(111) stepped surfaces depend strongly on the preparation method.

A comparative study of the effects of Ag2S films prepared by MPD and HRTD methods on the performance of polymer solar cells

NASA Astrophysics Data System (ADS)

Zhai, Yong; Li, Fumin; Ling, Lanyun; Chen, Chong

2016-10-01

In this work, the Ag2S nanocrystalline thin films are deposited on ITO glass via molecular precursor decomposition (MPD) method and newly developed HRTD method for organic solar cells (ITO/Ag2S/P3HT:PCBM/MoO3/Au) as an electron selective layer and a light absorption material. The surface morphology, structure characterization, and optical property of the Ag2S films prepared by these two methods were compared and the effect of the prepared Ag2S film on the device performance is investigated. It is found that the Ag2S films prepared by HRTD method have lower roughness and better uniformity than the corresponding films prepared by the MPD method. In addition, a more effective and rapid transporting ability for the electrons and holes in the ITO/Ag2S(HRTD, n)/P3HT:PCBM/MoO3/Au cells is found, which reduces the charge recombination, and thus, improves the device performance. The highest efficiency of 3.21% achieved for the ITO/Ag2S(HRTD, 50)/P3HT:PCBM/MoO3/Au cell is 93% higher than that of the ITO/Ag2S(MPD, 2)/P3HT:PCBM/MoO3/Au cell.

Application of surface analytical methods in thin film analysis

NASA Astrophysics Data System (ADS)

Wen, Xingu

Self-assembly and the sol-gel process are two promising methods for the preparation of novel materials and thin films. In this research, these two methods were utilized to prepare two types of thin films: self-assembled monolayers of peptides on gold and SiO2 sol-gel thin films modified with Ru(II) complexes. The properties of the resulting thin films were investigated by several analytical techniques in order to explore their potential applications in biomaterials, chemical sensors, nonlinear optics and catalysis. Among the analytical techniques employed in the study, surface analytical techniques, such as X-ray photoelectron spectroscopy (XPS) and grazing angle reflection absorption Fourier transform infrared spectroscopy (RA-FTIR), are particularly useful in providing information regarding the compositions and structures of the thin films. In the preparation of peptide thin films, monodisperse peptides were self-assembled on gold substrate via the N-terminus-coupled lipoic acid. The film compositions were investigated by XPS and agreed well with the theoretical values. XPS results also revealed that the surface coverage of the self-assembled films was significantly larger than that of the physisorbed films and that the chemisorption between the peptides and gold surface was stable in solvent. Studies by angle dependent XPS (ADXPS) and grazing angle RA-FTIR indicated that the peptides were on average oriented at a small angle from the surface normal. By using a model of orientation distribution function, both the peptide tilt angle and film thickness can be well calculated. Ru(II) complex doped SiO2 sol-gel thin films were prepared by low temperature sol-gel process. The ability of XPS coupled with Ar + ion sputtering to provide both chemical and compositional depth profile information of these sol-gel films was evaluated. This technique, together with UV-VIS and electrochemical measurements, was used to investigate the stability of Ru complexes in the composite films. The stability of Ru complexes with respect to dopant leaching was dependent on the film microstructures. Three methods aiming to improve the dopant stability were also explored. In addition, the ion exchange properties of the composite films, upon exposure to various ions in aqueous solutions, were investigated by XPS, and the ion exchange mechanism was elucidated.

Pore Structure and Fluoride Ion Adsorption Characteristics of Zr (IV) Surface-Immobilized Resin Prepared Using Polystyrene as a Porogen

NASA Astrophysics Data System (ADS)

Mizuki, Hidenobu; Ito, Yudai; Harada, Hisashi; Uezu, Kazuya

Zr(IV) surface-immobilized resins for removal of fluoride ion were prepared by surface template polymerization using polystyrene as a porogen. At polymerization, polystyrene was added in order to increase mesopores (2-50 nm) and macropore (>50 nm) with large macropores (around 300 nm) formed with internal aqueous phase of W⁄O emulsion. The pore structure of Zr(IV) surface-immobilized resins was evaluated by measuring specific surface area, pore volume, and pore size distribution with volumetric adsorption measurement instrument and mercury porosimeter. The adsorption isotherms were well fitted by Langmuir equation. The removal of fluoride was also carried out with column method. Zr(IV) surface-immobilized resins, using 10 g⁄L polystyrene in toluene at polymerization, possessed higher volume of not only mesopores and macropores but also large macropores. Furethermore, by adding the polystyrene with smaller molecular size, the pore volume of mesopores, macropores and large macropores was significantly increased, and the fluoride ion adsorption capacity and the column utilization also increased.

Development of Guidelines for In-Situ Repair of SLS-Class Composite Flight Hardware

NASA Technical Reports Server (NTRS)

Weber, Thomas P., Jr.; Cox, Sarah B.

2018-01-01

The purpose of composite repair development at KSC (John F. Kennedy Space Center) is to provide support to the CTE (Composite Technology for Exploration) project. This is a multi-space center effort with the goal of developing bonded joint technology for SLS (Space Launch System) -scale composite hardware. At KSC, effective and efficient repair processes need to be developed to allow for any potential damage to composite components during transport or launch preparation. The focus of the composite repair development internship during the spring of 2018 was on the documentation of repair processes and requirements for process controls based on techniques developed through hands-on work with composite test panels. Three composite test panels were fabricated for the purpose of repair and surface preparation testing. The first panel included a bonded doubler and was fabricated to be damaged and repaired. The second and third panels were both fabricated to be cut into lap-shear samples to test the strength of bond of different surface preparation techniques. Additionally, jointed composite test panels were impacted at MSFC (Marshall Space Flight Center) and analyzed for damage patterns. The observations after the impact tests guided the repair procedure at KSC to focus on three repair methods. With a finalized repair plan in place, future work will include the strength testing of different surface preparation techniques, demonstration of repair methods, and repair of jointed composite test panels being impacted at MSFC.

Icephobicity and the effect of water condensation on the superhydrophobic low-density polyethylene surface

NASA Astrophysics Data System (ADS)

Yuan, Zhiqing; Wang, Menglei; Huang, Juan; Wang, Xian; Bin, Jiping; Peng, Chaoyi; Xing, Suli; Xiao, Jiayu; Zeng, Jingcheng; Xiao, Ximei; Fu, Xin; Gong, Huifang; Zhao, Dejian; Chen, Hong

2015-06-01

A superhydrophobic surface was obtained on a low-density polyethylene (LDPE) substrate using a facile method. The water contact angle and the sliding angle of the superhydrophobic LDPE surface were 155 ± 2° and 4°, respectively. The ice shear stress of the superhydrophobic LDPE surface was 2.08 times smaller than that of the flat LDPE surface. The superhydrophobic surface still showed excellent icephobicity and superhydrophobicity after undergoing a circulatory icing/deicing procedure five times. In addition, water condensation and its effect on the icephobicity of the as-prepared superhydrophobic surface were also studied.

Fabrication of uniformly dispersed Ag nanoparticles loaded TiO{sub 2} nanotube arrays for enhancing photoelectrochemical and photocatalytic performances under visible light irradiation

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

Yi, Junhui; Zhang, Shengsen; Wang, Hongjuan

2014-12-15

Graphical abstract: Uniformly dispersed Ag nanoparticles (NPs) were successfully loaded on both the outer and inner surface of the TiO{sub 2} nanotube arrays (NTs) through a simple polyol method, which exhibited the enhanced photoelectrochemical and photocatalytic performances under visible-light irradiation due to the more effective separation of photo-generated electron–hole pairs and faster interfacial charge transfer. - Highlights: • Highly dispersed Ag nanoparticles (NPs) are successfully prepared by polyol method. • Ag NPs are uniformly loaded on the surface of the TiO{sub 2} nanotube arrays (NTs). • Ag/TiO{sub 2}-NTs exhibit the enhanced photocatalytic activity under visible-light. • The enhanced photocurrent ismore » explained by electrochemical impedance spectroscopy. - Abstract: Uniformly dispersed Ag nanoparticles (NPs) were successfully loaded on both the outer and inner surface of the TiO{sub 2} nanotube arrays (NTs) through a simple polyol method. The as-prepared Ag/TiO{sub 2}-NTs were characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and UV–vis diffusion reflectance spectroscopy. Photoelectrochemical behaviors were investigated via photocurrent response and electrochemical impedance spectroscopy (EIS). Photocatalytic activity of Ag/TiO{sub 2}-NTs was evaluated by degradation of acid orange II under visible light irradiation. The results showed that photocatalytic efficiency of Ag/TiO{sub 2}-NTs is more than 5 times higher than that of pure TiO{sub 2} NTs. Comparing with the electrochemical deposition method, the photocatalytic activity of Ag/TiO{sub 2}-NTs prepared by polyol method has been obviously increased.« less

Facile and rapid DNA extraction and purification from food matrices using IFAST (immiscible filtration assisted by surface tension).

PubMed

Strotman, Lindsay N; Lin, Guangyun; Berry, Scott M; Johnson, Eric A; Beebe, David J

2012-09-07

Extraction and purification of DNA is a prerequisite to detection and analytical techniques. While DNA sample preparation methods have improved over the last few decades, current methods are still time consuming and labor intensive. Here we demonstrate a technology termed IFAST (Immiscible Filtration Assisted by Surface Tension), that relies on immiscible phase filtration to reduce the time and effort required to purify DNA. IFAST replaces the multiple wash and centrifugation steps required by traditional DNA sample preparation methods with a single step. To operate, DNA from lysed cells is bound to paramagnetic particles (PMPs) and drawn through an immiscible fluid phase barrier (i.e. oil) by an external handheld magnet. Purified DNA is then eluted from the PMPs. Here, detection of Clostridium botulinum type A (BoNT/A) in food matrices (milk, orange juice), a bioterrorism concern, was used as a model system to establish IFAST's utility in detection assays. Data validated that the DNA purified by IFAST was functional as a qPCR template to amplify the bont/A gene. The sensitivity limit of IFAST was comparable to the commercially available Invitrogen ChargeSwitch® method. Notably, pathogen detection via IFAST required only 8.5 μL of sample and was accomplished in five-fold less time. The simplicity, rapidity and portability of IFAST offer significant advantages when compared to existing DNA sample preparation methods.

Optical properties of titanium-di-oxide (TiO2) prepared by hydrothermal method

NASA Astrophysics Data System (ADS)

Rahman, Kazi Hasibur; Biswas, Sayari; Kar, Asit Kumar

2018-05-01

Research on titanate and its derived TiO2 nanostructures with large specific surface area have received great attention due to their enhanced efficiency in photocatalysis, DSSC etc. Here, in this communication TiO2 powder has been prepared by hydrothermal method at 180 °C. In this work we have shown the changes in optical properties of the powder with two different sintering temperatures ‒ 500 °C and 800 °C. The as prepared powder was also studied. FESEM images show spherical particles for the as prepared samples which look more like agglomeration after sintering. Band gaps of the prepared samples were calculated from UV-Vis spectroscopy which lies in the range 2.85 eV ‒ 3.13 eV. The photoluminescence (PL) spectra of the prepared samples were recorded at room temperature in the range of 300‒700 nm. It shows two distinct peaks at 412 nm and 425 nm.

Two Synthetic Methods for Preparation of Chiral Stationary Phases Using Crystalline Degradation Products of Vancomycin: Column Performance for Enantioseparation of Acidic and Basic Drugs.

PubMed

Abdollahpour, Assem; Heydari, Rouhollah; Shamsipur, Mojtaba

2017-07-01

Two chiral stationary phases (CSPs) based on crystalline degradation products (CDPs) of vancomycin by using different synthetic methods were prepared and compared. Crystalline degradation products of vancomycin were produced by hydrolytic loss of ammonia from vancomycin molecules. Performances of two chiral columns prepared with these degradation products were investigated using several acidic and basic drugs as model analytes. Retention and resolution of these analytes on the prepared columns, as two main parameters, in enantioseparation were studied. The results demonstrated that the stationary phase preparation procedure has a significant effect on the column performance. The resolving powers of prepared columns for enantiomers resolution were changed with the variation in vancomycin-CDP coverage on the silica support. Elemental analysis was used to monitor the surface coverage of silica support by vancomycin-CDP. The results showed that both columns can be successfully applied to chiral separation studies.

Influence of surfaces modified with biomimetic extracellular matrices on adhesion and proliferation of mesenchymal stem cells and osteosarcoma cells.

PubMed

Cai, Rong; Kawazoe, Naoki; Chen, Guoping

2015-02-01

Preparation of surfaces modified with biomimetic extracellular matrices (ECMs) is important for investigation of the interaction between ECMs and cells. In the present study, surfaces modified with ECMs from normal somatic cells, stem cells and tumor cells were prepared by cell culture method. The ECMs derived from bone marrow-derived mesenchymal stem cells (MSCs), dermal fibroblasts (FBs), osteoblasts (OBs) and MG63 osteosarcoma cells were deposited on the surfaces of cell-culture polystyrene plates (TCPS). The ECMs from different cell types had different compositions. The effects of the ECM-deposited surfaces on the adhesion, spreading and proliferation of MSCs and MG63 human osteosarcoma cells were dependent on the type of both ECMs and cells. The surfaces deposited with ECMs from MSCs, FBs and OBs promoted cell adhesion more strongly than surfaces deposited with ECMs from MG63 cells and TCPS. Compared to TCPS, the ECM-deposited surfaces promoted proliferation of MSCs while they inhibited the proliferation of MG63 cells. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis of ZnO nanoparticles for oil-water interfacial tension reduction in enhanced oil recovery

NASA Astrophysics Data System (ADS)

Soleimani, Hassan; Baig, Mirza Khurram; Yahya, Noorhana; Khodapanah, Leila; Sabet, Maziyar; Demiral, Birol M. R.; Burda, Marek

2018-02-01

Nanoparticles show potential use in applications associated with upstream oil and gas engineering to increase the performance of numerous methods such as wettability alteration, interfacial tension reduction, thermal conductivity and enhanced oil recovery operations. Surface tension optimization is an important parameter in enhanced oil recovery. Current work focuses on the new economical method of surface tension optimization of ZnO nanofluids for oil-water interfacial tension reduction in enhanced oil recovery. In this paper, zinc oxide (ZnO) nanocrystallites were prepared using the chemical route and explored for enhanced oil recovery (EOR). Adsorption of ZnO nanoparticles (NPs) on calcite (111) surface was investigated using the adsorption locator module of Materials Studio software. It was found that ZnO nanoparticles show maximum adsorption energy of - 253 kcal/mol. The adsorption of ZnO on the rock surface changes the wettability which results in capillary force reduction and consequently increasing EOR. The nanofluids have been prepared by varying the concentration of ZnO nanoparticles to find the optimum value for surface tension. The surface tension (ST) was calculated with different concentration of ZnO nanoparticles using the pendant drop method. The results show a maximum value of ST 35.57 mN/m at 0.3 wt% of ZnO NPs. It was found that the nanofluid with highest surface tension (0.3 wt%) resulted in higher recovery efficiency. The highest recovery factor of 11.82% at 0.3 wt% is due to the oil/water interfacial tension reduction and wettability alteration.

Evaluation of the hygiene of ready-to-eat food preparation areas and practices in mobile food vendors in the UK.

PubMed

Little, Christine; Sagoo, Satnam

2009-12-01

This study was undertaken to assess the cleanliness of food preparation areas, cleaning methods used, and the microbiological quality of water used by 1258 mobile food vendors in the UK. Samples collected included potable water (1102), cleaning cloths (801) and environmental swabs from food preparation surfaces (2704). Cleaning cloths were more heavily contaminated with Aerobic Colony Counts, Enterobacteriaceae, Escherichia coli, and Staphylococcus aureus compared to surfaces sampled. Surfaces that were visually dirty, wet, and chopping boards that were plastic or damaged also had high levels of these bacteria. Fifty-four percent of potable water samples were of poor microbiological quality; i.e. contained coliforms, E. coli and/or enterococci. A documented food safety management system was only evident in 40.1% of vendors and cleaning schedules were only used by 43.6%. Deficiencies in the correct use of cleaning materials, such as dilution factors and the minimum contact time for disinfectants, were identified.

Argon-oxygen atmospheric pressure plasma treatment on carbon fiber reinforced polymer for improved bonding

NASA Astrophysics Data System (ADS)

Chartosias, Marios

Acceptance of Carbon Fiber Reinforced Polymer (CFRP) structures requires a robust surface preparation method with improved process controls capable of ensuring high bond quality. Surface preparation in a production clean room environment prior to applying adhesive for bonding would minimize risk of contamination and reduce cost. Plasma treatment is a robust surface preparation process capable of being applied in a production clean room environment with process parameters that are easily controlled and documented. Repeatable and consistent processing is enabled through the development of a process parameter window utilizing techniques such as Design of Experiments (DOE) tailored to specific adhesive and substrate bonding applications. Insight from respective plasma treatment Original Equipment Manufacturers (OEMs) and screening tests determined critical process factors from non-factors and set the associated factor levels prior to execution of the DOE. Results from mode I Double Cantilever Beam (DCB) testing per ASTM D 5528 [1] standard and DOE statistical analysis software are used to produce a regression model and determine appropriate optimum settings for each factor.

Preparation of activated carbon hollow fibers from ramie at low temperature for electric double-layer capacitor applications.

PubMed

Du, Xuan; Zhao, Wei; Wang, Yi; Wang, Chengyang; Chen, Mingming; Qi, Tao; Hua, Chao; Ma, Mingguo

2013-12-01

Activated carbon hollow fibers (ACHFs) with high surface area were prepared from inexpensive, renewable ramie fibers (RFs) by a single-step activation method under lower temperature than that of other reports. The effects of activation conditions on the pore structure and turbostratic structure of ACHFs were investigated systematically. The results show that ACHFs surface area decreased but micropore volume and conductivity increased as the increase of activation temperature and activation time. The electrochemical measurements of supercapacitors fabricated from these ACHFs electrodes reveal that the electrochemical properties improved with the enhancing of activation degree. However, too high activation temperature can make the ion diffusion resistance increase. It suggests that pore structure and conductivity are as important as surface area to decide the electrochemical performances of ACHFs electrode materials. A maximum capacity of 287 F g(-1) at 50 mA g(-1) was obtained for the ACHFs electrode prepared under suitable conditions. Copyright © 2013 Elsevier Ltd. All rights reserved.

Antibody derivatization and conjugation strategies: application in preparation of stealth immunoliposome to target chemotherapeutics to tumor.

PubMed

Manjappa, Arehalli S; Chaudhari, Kiran R; Venkataraju, Makam P; Dantuluri, Prudhviraju; Nanda, Biswarup; Sidda, Chennakesavulu; Sawant, Krutika K; Murthy, Rayasa S Ramachandra

2011-02-28

A great deal of effort has been made over the years to develop liposomes that have targeting vectors (oligosaccharides, peptides, proteins and vitamins) attached to the bilayer surface. Most studies have focused on antibody conjugates since procedures for producing highly specific monoclonal antibodies are well established. Antibody conjugated liposomes have recently attracted a great deal of interest, principally because of their potential use as targeted drug delivery systems and in diagnostic applications. A number of methods have been reported for coupling antibodies to the surface of stealth liposomes. The objective of this review is to enumerate various strategies which are employed in the modification and conjugation of antibodies to the surface of stealth liposomes. This review also describes various derivatization techniques of lipids prior and after their use in the preparation of liposomes. The use of single chain variable fragments and affibodies as targeting ligands in the preparation of immunoliposomes is also discussed. Copyright © 2010 Elsevier B.V. All rights reserved.

Spectroscopic Studies on the Effect of Some Ferrocene Derivatives in the Formation of Silver Nanoparticles.

PubMed

Sanyal, Manik Kumar; Biswas, Bipul; Chowdhury, Avijit; Mallik, Biswanath

2016-06-01

Silver nanoparticles were prepared by microwave assisted method using silver nitrate as precursor in the presence of some ferrocene derivatives. The formation of the silver nanoparticles was monitored using UV-Vis spectroscopy. The UV-Vis spectroscopy revealed the formation of silver nanoparticles by exhibiting typical surface plasmon absorption band. The position of plasmon band (406-429 nm) was observed to depend on the nature of a particular ferrocene derivative used. TEM images indicated that the nanoparticles were spherical in shape and well-dispersed. Quantum dots (3.2 nm) were prepared by using ferrocenecarboxylic acid. The surface plasmon absorption band has shown red shift with increasing concentration of ferrocene derivative. For different duration of microwave heating time, intensity of absorption spectra in general was found to increase except in presence of ferrocene carbaldehyde where it decreased. Time-dependent spectra have indicated almost stable position of the surface plasmon band with increasing time of observation confirming that the as prepared silver nanoparticles did not aggregate with lapse of time.

Evaluation of Alternative Peel Ply Surface Preparation Methods of SC-15 Epoxy / Fiberglass Composite Surfaces for Secondary Bonding

DTIC Science & Technology

2014-01-01

pressure of 325 kPa (40 psi) at the peak of the temperature ramp of the cure schedule (13). The higher hold pressure requires the use of a high -pressure...Henkel Corporation Aerospace Group. Hysol EA 9896 Peel Ply; Preliminary Technical Datasheet, Bay Point, CA, February 2010. 11. Airtech Advanced ...using FM 94K epoxy film adhesive by mechanical testing, elemental surface analysis, and high -resolution imaging of failure surfaces. Woven S2

Improved surface hydrophilicity and antifouling property of polysulfone ultrafiltration membrane with poly(ethylene glycol) methyl ether methacrylate grafted graphene oxide nanofillers

NASA Astrophysics Data System (ADS)

Wang, Haidong; Lu, Xiaofei; Lu, Xinglin; Wang, Zhenghui; Ma, Jun; Wang, Panpan

2017-12-01

In this study, the GO-g-P(PEGMA) nanoplates were first synthesized by grafting hydrophilic poly (poly (ethylene glycol) methyl ether methacrylate) via surface-initiated atom transfer radical polymerization (SI-ATRP) method. A novel polysulfone (PSF) nanocomposite membrane using GO-g-P(PEGMA) nanoplates as nanofillers was fabricated. FTIR, TGA, 1H NMR, GPC and TEM were applied to verify the successful synthesis of the prepared nanoplates, while SEM, AFM, XPS, contact angle goniometry and filtration experiments were used to characterize the fabricated nanocomposite membranes. It was found that the new prepared nanofillers were well dispersed in organic PSF matrix, and the PSF/GO-g-P(PEGMA) nanocomposite membrane showed significant improvements in water flux and flux recovery rate. Based on the results of resistance-in-series model, the nanocomposite membrane exhibited superior resistance to the irreversible fouling. The excellent filtration and antifouling performance are attributed to the segregation of GO-g-P(PEMGA) nanofillers toward the membrane surface and the pore walls. Notably, the blended nanofillers appeared a stable retention in/on nanocomposite membrane after 30 days of washing time. The demonstrated method of synthesis GO-g-P(PEGMA) in this study can also be extended to preparation of other nanocomposite membrane in future.

Surface modifications induced by pulsed-laser texturing—Influence of laser impact on the surface properties

NASA Astrophysics Data System (ADS)

Costil, S.; Lamraoui, A.; Langlade, C.; Heintz, O.; Oltra, R.

2014-01-01

Laser cleaning technology provides a safe, environmentally friendly and very cost effective way to improve cleaning and surface preparation of metallic materials. Compared with efficient cleaning processes, it can avoid the disadvantages of ductile materials prepared by conventional technologies (cracks induced by sand-blasting for example) and treat only some selected areas (due to the optical fibers). By this way, laser technology could have several advantages and expand the range of thermal spraying. Moreover, new generations of lasers (fiber laser, disc laser) allow the development of new methods. Besides a significant bulk reduction, no maintenance, low operating cost, laser fibers can introduce alternative treatments. Combining a short-pulse laser with a scanner allows new applications in terms of surface preparation. By multiplying impacts using scanning laser, it is possible to shape the substrate surface to improve the coating adhesion as well as the mechanical behaviour. In addition, during the interactions of the laser beam with metallic surfaces, several modifications can be induced and particularly thermal effects. Indeed, under ambient conditions, a limited oxidation of the clean surface can occur. This phenomenon has been investigated in detail for silicon but few works have been reported concerning metallic materials. This paper aims at studying the surface modifications induced on aluminium alloy substrates after laser texturing. After morphological observations (SEM), a deeper surface analysis will be performed using XPS (X-ray photoelectron spectroscopy) measures and microhardness testing.

Poly(organo phosphazene) nanoparticles surface modified with poly(ethylene oxide).

PubMed

Vandorpe, J; Schacht, E; Stolnik, S; Garnett, M C; Davies, M C; Illum, L; Davis, S S

1996-10-05

The use of biodegradable derivatives of poly(organo phosphazenes) for the preparation of nanoparticles and their surface modification with the novel poly(ethylene oxide) derivative of poly(organo phosphazene) has been assessed using a range of in vitro characterization methods. The nanoparticles were produced by the precipitation solvent evaporation method from the derivative co-substituted with phenylalanine and glycine ethyl ester side groups. A reduction in particle size to less than 200 nm was achieved by an increase in pH of the preparation medium. The formation (and colloidal stability) of these nanoparticles seems to be controlled by two opposite effects: attractive hydrophobic interactions between phenylalanine ester groups and electrostatic repulsions arising from the carboxyl groups formed due to (partial) hydrolysis of the ester bond(s) at the high pH of the preparation medium. The poly[(glycine ethyl ester)phosphazene] derivative containing 5000-Da poly(ethylene oxide) as 5% of the side groups was used for the surface modification of nanoparticles. Adsorbed onto the particles, the polymer produced a thick coating layer of approximately 35 nm. The coated nanoparticles exhibited reduced surface negative potential and improved colloidal stability toward electrolyte-induced flocculation, relative to the uncoated system. However, the steric stabilization provided was less effective than that of a Poloxamine 908 coating. This difference in effectiveness of the steric stabilization might indicate that, although both the stabilizing polymers possess a 5000-Da poly(ethylene oxide) moiety, there is a difference in the arrangements of these poly(ethylene oxide) chains at the particle surface. (c) 1996 John Wiley & Sons, Inc.

Gas-tungsten arc welding of aluminum alloys

DOEpatents

Frye, Lowell D.

1984-01-01

A gas-tungsten arc welding method for joining together structures formed of aluminum alloy with these structures disposed contiguously to a heat-damagable substrate of a metal dissimilar to the aluminum alloy. The method of the present invention is practiced by diamond machining the fay surfaces of the aluminum alloy structures to provide a mirror finish thereon having a surface roughness in the order of about one microinch. The fay surfaces are aligned and heated sufficiently by the tungsten electrode to fuse the aluminum alloy contiguous to the fay surfaces to effect the weld joint. The heat input used to provide an oxide-free weld is significantly less than that required if the fay surfaces were prepared by using conventional chemical and mechanical practices.

Role of Microstructure in High Temperature Oxidation.

DTIC Science & Technology

1980-05-01

Surface Prepartion Upon Oxidation ......... .................. 20 EXPERIMENTAL METHODS 21 Speciemen Preparation...angle sectioning method 26 Figure 3. Application of the test line upon the image of NiO scale to determine the number of the NiO grain boundary...of knowledge in this field was readily accounted for by extreme experimental difficulty in applying standard methods of microscopy to the thin

METHOD OF FORMING A FUEL ELEMENT FOR A NUCLEAR REACTOR

DOEpatents

Layer, E.H. Jr.; Peet, C.S.

1962-01-23

A method is given for preparing a fuel element for a nuclear reactor. The method includes the steps of sandblasting a body of uranium dioxide to roughen the surface thereof, depositing a thin layer of carbon thereon by thermal decomposition of methane, and cladding the uranium dioxide body with zirconium by gas pressure bonding. (AEC)

Method of depositing an electrically conductive oxide buffer layer on a textured substrate and articles formed therefrom

DOEpatents

Paranthaman, M. Parans; Aytug, Tolga; Christen, David K.

2005-10-18

An article with an improved buffer layer architecture includes a substrate having a textured metal surface, and an electrically conductive lanthanum metal oxide epitaxial buffer layer on the surface of the substrate. The article can also include an epitaxial superconducting layer deposited on the epitaxial buffer layer. An epitaxial capping layer can be placed between the epitaxial buffer layer and the superconducting layer. A method for preparing an epitaxial article includes providing a substrate with a metal surface and depositing on the metal surface a lanthanum metal oxide epitaxial buffer layer. The method can further include depositing a superconducting layer on the epitaxial buffer layer, and depositing an epitaxial capping layer between the epitaxial buffer layer and the superconducting layer.

Method of depositing an electrically conductive oxide buffer layer on a textured substrate and articles formed therefrom

DOEpatents

Paranthaman, M. Parans; Aytug, Tolga; Christen, David K.

2003-09-09

An article with an improved buffer layer architecture includes a substrate having a textured metal surface, and an electrically conductive lanthanum metal oxide epitaxial buffer layer on the surface of the substrate. The article can also include an epitaxial superconducting layer deposited on the epitaxial buffer layer. An epitaxial capping layer can be placed between the epitaxial buffer layer and the superconducting layer. A method for preparing an epitaxial article includes providing a substrate with a metal surface and depositing on the metal surface a lanthanum metal oxide epitaxial buffer layer. The method can further include depositing a superconducting layer on the epitaxial buffer layer, and depositing an epitaxial capping layer between the epitaxial buffer layer and the superconducting layer.

A sample preparation method for recovering suppressed analyte ions in MALDI TOF MS.

PubMed

Lou, Xianwen; de Waal, Bas F M; Milroy, Lech-Gustav; van Dongen, Joost L J

2015-05-01

In matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS), analyte signals can be substantially suppressed by other compounds in the sample. In this technical note, we describe a modified thin-layer sample preparation method that significantly reduces the analyte suppression effect (ASE). In our method, analytes are deposited on top of the surface of matrix preloaded on the MALDI plate. To prevent embedding of analyte into the matrix crystals, the sample solution were prepared without matrix and efforts were taken not to re-dissolve the preloaded matrix. The results with model mixtures of peptides, synthetic polymers and lipids show that detection of analyte ions, which were completely suppressed using the conventional dried-droplet method, could be effectively recovered by using our method. Our findings suggest that the incorporation of analytes in the matrix crystals has an important contributory effect on ASE. By reducing ASE, our method should be useful for the direct MALDI MS analysis of multicomponent mixtures. Copyright © 2015 John Wiley & Sons, Ltd.

Annealing temperature dependent reversible wettability switching of micro/nano structured ZnO superhydrophobic surfaces

NASA Astrophysics Data System (ADS)

Velayi, Elmira; Norouzbeigi, Reza

2018-05-01

Superhydrophobic ZnO surfaces with reversibly tunable wettability were fabricated on stainless steel meshes via a facile chemical bath deposition method just by regulating the micro/nano structured ZnO needles without using chemical post modifications. The obtained surfaces can be easily and reversibly switched between superhydrophobic and superhydrophilic/underwater superoleophobic characteristics by altering the annealing temperatures. As-prepared sample exhibited long-term superhydrophobic properties with a water contact angle (WCA) of 163.8° ± 1.8° and contact angle hysteresis (CAH) of 1.1° ± 0.8°. The SEM, XRD, XPS and Raman analyses were employed to characterize the morphological features and surface chemistry of the prepared samples. SEM images showed the formation of ZnO micro/nanoneedles with a diameter of ∼90 nm on the substrate. The superhydrophobic ZnO surface was switched to highly hydrophilic and underwater superoleophobic properties with an oil contact angle (OCA) of about 172.5° after being annealed at 400 °C in air for 30 min and restored to superhydrophobic state again by altering the annealing temperature to 150 °C. Mechanical durability of the ZnO superhydrophobic surface was tested by an abrasion test. Results confirmed that the prepared surface exhibited an excellent robustness after 20 abrasion cycles under the pressure of 4.7 kPa.

Enzymatic preparation of nanocrystalline and microcrystalline cellulose

Treesearch

Sarah R. Anderson; Dominic Esposito; William Gillette; J.Y. Zhu; Ulrich Baxa; Scott E. Mcneil

2014-01-01

Traditional cellulose nanocrystal (CNC) production methods use harsh chemicals, are energetically expensive, and result in a hydrophilic sulfate surface chemistry with limited utility. Enzymatic production of CNCs is a less expensive alternative production method that eliminates the need for harsh chemicals and requires much less energy for mechanical fibrillation and...

Joining of advanced materials by superplastic deformation

DOEpatents

Goretta, Kenneth C.; Routbort, Jules L.; Gutierrez-Mora, Felipe

2008-08-19

A method for utilizing superplastic deformation with or without a novel joint compound that leads to the joining of advanced ceramic materials, intermetallics, and cermets. A joint formed by this approach is as strong as or stronger than the materials joined. The method does not require elaborate surface preparation or application techniques.

Joining of advanced materials by superplastic deformation

DOEpatents

Goretta, Kenneth C.; Routbort, Jules L.; Gutierrez-Mora, Felipe

2005-12-13

A method for utilizing superplastic deformation with or without a novel joint compound that leads to the joining of advanced ceramic materials, intermetallics, and cermets. A joint formed by this approach is as strong as or stronger than the materials joined. The method does not require elaborate surface preparation or application techniques.

A novel method for preparation of high dense tetragonal Li7La3Zr2O12

NASA Astrophysics Data System (ADS)

Zhao, Pengcheng; Wen, Yuehua; Cheng, Jie; Cao, Gaoping; Jin, Zhaoqing; Ming, Hai; Xu, Yan; Zhu, Xiayu

2017-03-01

For conventional preparation methods of Li7La3Zr2O12 (LLZO) solid state electrolytes, there is a stereotype that higher density always comes from higher pressure enforced upon the LLZO pellets. In this paper, a different way with an auto-consolidation mechanism is provided and discussed. No pressing operations are employed during the whole preparation process. Due to the surface tension of liquid melted Li2O at sintering temperature, LLZO particles could aggregate together freely and automatically. The preparation process for dense LLZO is greatly simplified. A dense tetragonal LLZO with high relative density about 93% has been prepared successfully by this auto-consolidation method. And there are no voids observed in the SEM images. At 30 °C, the total conductivity is about 5.67 × 10-5 S cm-1, which is the highest one for tetragonal LLZO in the reported issues, even two times higher than that prepared by hot-pressing method. The activation energy for total conductivity is ∼0.35 eV atom-1 at 30-120 °C, slightly lower than the previous reported values. This work sheds light on the understanding of the consolidation mechanism for solid electrolytes and suggests a reliable route to syhthesize cemanic solid electrolytes.

Silicon micro-mold and method for fabrication

DOEpatents

Morales, Alfredo M.

2005-01-11

The present invention describes a method for rapidly fabricating a robust 3-dimensional silicon micro-mold for use in preparing complex metal micro-components. The process begins by depositing a conductive metal layer onto one surface of a silicon wafer. A thin photoresist and a standard lithographic mask are then used to transfer a trace image pattern onto the opposite surface of the wafer by exposing and developing the resist. The exposed portion of the silicon substrate is anisotropically etched through the wafer thickness down to conductive metal layer to provide an etched pattern consisting of a series of rectilinear channels and recesses in the silicon which serve as the silicon micro-mold. Microcomponents are prepared with this mold by first filling the mold channels and recesses with a metal deposit, typically by electroplating, and then removing the silicon micro-mold by chemical etching.

Preparation of regenerable granular carbon nanotubes by a simple heating-filtration method for efficient removal of typical pharmaceuticals

NASA Astrophysics Data System (ADS)

Shan, Danna; Deng, Shubo; Zhao, Tianning; Yu, Gang; Winglee, Judith; Wiesner, Mark R.

2017-04-01

A simple and convenient method was used to prepare novel granular carbon nanotubes (CNTs) for enhanced adsorption of pharmaceuticals. By heating CNTs powder at 450 degree centigrade in air, followed by filtration, the obtained granular adsorbent exhibited high surface area and pore volume since the heating process produced some oxygen-containing functional groups on CNT surface, making CNTs more dispersible in the formation of granular cake. The porous granular CNTs not only had more available surfaces for adsorption but also were more easily separated from solution than pristine CNTs (p-CNTs) powder. This adsorbent exhibited relatively fast adsorption for carbamazepine (CBZ), tetracycline (TC) and diclofe- nac sodium (DS), and the maximum adsorption capacity on the granular CNTs was 369.5 μmol/g for CBZ, 284.2 μmol/g for TC and 203.1 μmol/g for DS according to the Langmuir fitting, increasing by 42.4%, 37.8% and 38.0% in comparison with the pristine CNTs powder. Moreover, the spent granular CNTs were successfully regenerated at 400 degree centigrade in air without decreasing the adsorption capacity in five regeneration cycles. The adsorbed CBZ and DS were completely degraded, while the adsorbed TC was partially oxidized and the residual was favorable for the subsequent adsorption. This research develops an easy method to prepare and regenerate granular CNT adsorbent for the enhanced removal of organic pollutants from water or wastewater.

ELECTROSTATIC AIR CLEANING DEVICE AND METHOD

DOEpatents

Silverman, L.; Anderson, D.M.

1961-07-18

A method and apparatus for utilizing friction-charged particulate material from an aerosol are described. A bed of the plastic spheres is prepared, and the aerosol is passed upwardly through the bed at a rate just large enough to maintain the bed in a fluidized state wim over-all circulation of the balls. Wire members criss-crossing through the bed rub against the balls and maintain their surfaces with electrostatic charges. The particulate material in the aerosol adheres to the surfaces of the balls.

Electrochemical synthesis of gold nanoparticles on the surface of multi-walled carbon nanotubes with glassy carbon electrode and their application

NASA Astrophysics Data System (ADS)

Song, Y. Z.; Li, X.; Song, Y.; Cheng, Z. P.; Zhong, H.; Xu, J. M.; Lu, J. S.; Wei, C. G.; Zhu, A. F.; Wu, F. Y.; Xu, J.

2013-01-01

Gold nanoparticles on the surface of multi-walled carbon nanotubes with glassy carbon electrode were prepared using electrochemical synthesis method. The thin films of gold Nanoparticles/multi-walled carbon nanotubes were characterized by scanning electron microscopy, powder X-ray diffraction, and cyclic voltammetry. Electrochemical behavior of adrenaline hydrochloride at gold nanoparticles/multi-walled carbon nanotube modified glassy carbon electrode was investigated. A simple, sensitive, and inexpensive method for determination of adrenaline hydrochloride was proposed.

Comparative evaluation of surface topography of tooth prepared using erbium, chromium: Yttrium, scandium, gallium, garnet laser and bur and its clinical implications.

PubMed

Verma, Mahesh; Kumari, Pooja; Gupta, Rekha; Gill, Shubhra; Gupta, Ankur

2015-01-01

Erbium, chromium: Yttrium, scandium, gallium, garnet (Er, Cr: YSGG) laser has been successfully used in the ablation of dental hard and soft tissues. It has been reported that this system is also useful for preparing tooth surfaces and etching, but no consensus exist in the literature regarding the advantage of lasers over conventional tooth preparation technique. Labial surfaces of 25 extracted human maxillary central incisors were divided into two halves. Right half was prepared with diamond bur and left half with Er, Cr; YSGG laser and a reduction of 0.3-0.5 mm was carried out. Topography of prepared surfaces of five teeth were examined under scanning electron microscope (SEM). The remaining samples were divided into 4 groups of 10 specimens each based on the surface treatment received: One group was acid etched and other was nonetched. Composite resin cylinders were bonded on prepared surfaces and shear bond strength was assessed using a universal testing machine. The SEM observation revealed that the laser prepared surfaces were clean, highly irregular and devoid of a smear layer. Bur prepared surfaces were relatively smooth but covered with smear layer. Highest bond strength was shown by laser prepared acid etched group, followed by bur prepared the acid etched group. The bur prepared nonacid etched group showed least bond strength. Er, Cr: YSGG laser can be used for preparing tooth and bond strength value achieved by laser preparation alone without surface treatment procedure lies in the range of clinical acceptability.

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

McCormac, Kathleen; Byrd, Ian; Brannen, Rodney

We prepared highly porous Si/TiO 2 composite nanofibres using a unique sulphur-templating method combined with electrospinning. The structure, morphology, surface area, phase and composition of these nanofibres were characterized using Raman spectroscopy, scanning electron microscopy, powder X-ray diffraction, surface area analyser and thermogravimetric analyser. The specific surface area of Si/TiO 2 porous NFs is as large as 387m 2g -1, whose silicon capacity can be maintained above 1580mAhg -1 in 180 cycles.

Magnesium oxide prepared via metal-chitosan complexation method: Application as catalyst for transesterification of soybean oil and catalyst deactivation studies

NASA Astrophysics Data System (ADS)

Almerindo, Gizelle I.; Probst, Luiz F. D.; Campos, Carlos E. M.; de Almeida, Rusiene M.; Meneghetti, Simoni M. P.; Meneghetti, Mario R.; Clacens, Jean-Marc; Fajardo, Humberto V.

2011-10-01

A simple method to prepare magnesium oxide catalysts for biodiesel production by transesterification reaction of soybean oil with ethanol is proposed. The method was developed using a metal-chitosan complex. Compared to the commercial oxide, the proposed catalysts displayed higher surface area and basicity values, leading to higher yield in terms of fatty acid ethyl esters (biodiesel). The deactivation of the catalyst due to contact with CO2 and H2O present in the ambient air was verified. It was confirmed that the active catalytic site is a hydrogenocarbonate adsorption site.

Temperature Increase during Different Post Space Preparation Systems: An In Vitro Study

PubMed Central

Nazari Moghadam, Kiumars; Shahab, Shahriar; Shirvani, Soghra; Kazemi, Ali

2011-01-01

 INTRODUCTION: The purpose of this study was to evaluate external root surface temperature rise during post space preparation using LA Axxess bur, Beefill pack System, and Peeso Reamer drill. MATERIALS AND METHODS: The distal canals of forty-five extracted human permanent mandibular first molars were instrumented in crown-apical manner and obturated with lateral condensation technique. Teeth were then randomly divided into three groups according to post space preparation technique including: group 1. LA Axxess bur (Sybronendo Co., CA, USA), group 2 Beefill pack System (VD W Co., Munich, Germany) and group 3 Peeso Reamer drill (Mani Co., Tochigi-ken, Japan). Temperature was measured by means of digital thermometer MT-405 (Comercio Co., Sao Paulo, Brazil) which was installed on the root surfaces. Data was collected and submitted to one-way ANOVA and Post hoc analysis. RESULTS: Root surface temperatures were found to be significantly higher (7.3±2.7 vs. 4.3±2.1 and 4±2.4,) in samples of Beefill pack System compared with the two other groups (P<0.02). CONCLUSION: Using Beefill pack System during post space preparation may be potentially hazardous for periodontal tissues. PMID:24778690

An Efficient Covalent Coating on Glass Slides for Preparation of Optical Oligonucleotide Microarrays

PubMed Central

Pourjahed, Atefeh; Rabiee, Mohammad; Tahriri, Mohammadreza

2013-01-01

Objective(s): Microarrays are potential analyzing tools for genomics and proteomics researches, which is in needed of suitable substrate for coating and also hybridization of biomolecules. Materials and Methods: In this research, a thin film of oxidized agarose was prepared on the glass slides which previously coated with poly-L-lysine (PLL). Some of the aldehyde groups of the activated agarose linked covalently to PLL amine groups; also bound to the amino groups of biomolecules. These linkages were fixed by UV irradiation. The prepared substrates were compared to only agarose-coated and PLL-coated slides. Results: Results on atomic force microscope (AFM) demonstrated that agarose provided three-dimensional surface which had higher loading and bindig capacity for biomolecules than PLL-coated surface which had two-dimensional surface. In addition, the signal-to-noise ratio in hybridization reactions performed on the agarose-PLL coated substrates increased two fold and four fold compared to agarose and PLL coated substrates, respectively. Conclusion: The agarose-PLL microarrays had the highest signal (2546) and lowest background signal (205) in hybridization, suggesting that the prepared slides are suitable in analyzing wide concentration range of analytes. PMID:24570832

The Effect of Interfacial Chemical Bonding in TiO2-SiO2 Composites on Their Photocatalytic NOx Abatement Performance

PubMed Central

Hakki, Amer; Yang, Lu; Wang, Fazhou; Macphee, Donald E.

2017-01-01

The chemical bonding of particulate photocatalysts to supporting material surfaces is of great importance in engineering more efficient and practical photocatalytic structures. However, the influence of such chemical bonding on the optical and surface properties of the photocatalyst and thus its photocatalytic activity/reaction selectivity behavior has not been systematically studied. In this investigation, TiO2 has been supported on the surface of SiO2 by means of two different methods: (i) by the in situ formation of TiO2 in the presence of sand quartz via a sol-gel method employing tetrabutyl orthotitanium (TBOT); and (ii) by binding the commercial TiO2 powder to quartz on a surface silica gel layer formed from the reaction of quartz with tetraethylorthosilicate (TEOS). For comparison, TiO2 nanoparticles were also deposited on the surfaces of a more reactive SiO2 prepared by a hydrolysis-controlled sol-gel technique as well as through a sol-gel route from TiO2 and SiO2 precursors. The combination of TiO2 and SiO2, through interfacial Ti-O-Si bonds, was confirmed by FTIR spectroscopy and the photocatalytic activities of the obtained composites were tested for photocatalytic degradation of NO according to the ISO standard method (ISO 22197−1). The electron microscope images of the obtained materials showed that variable photocatalyst coverage of the support surface can successfully be achieved but the photocatalytic activity towards NO removal was found to be affected by the preparation method and the nitrate selectivity is adversely affected by Ti-O-Si bonding. PMID:28715384

Superhydrophobic hierarchical structure carbon mesh films for oil/water separation application

NASA Astrophysics Data System (ADS)

Lu, Zhaoxia; Huang, Xing; Wang, Lisheng

2017-08-01

In this study, we showed that a superoleophobic mesh with the self-cleaning ability could be readily prepared by a facile spray-coating method on stainless steel mesh. Poly(methyl methacrylate) was employed to provide a stable strength between carbon nanotubes and steel mesh surface. The effect of opening size of these steel meshes on surface wetting has been investigated. The dynamics of liquid droplets was investigated as well. The as-prepared meshes exhibited both superhydrophobicity and superoleophilicity and could effectively separate water from the oil and water mixture. The present study contributes to the development of oil and water separation materials for marine industrial application.

Rapid and Clean Covalent Attachment of Methylsiloxane Polymers and Oligomers to Silica Using B(C6F5)3 Catalysis.

PubMed

Flagg, Daniel H; McCarthy, Thomas J

2017-08-22

The rapid, room-temperature covalent attachment of alkylhydridosilanes (R 3 Si-H) to silicon oxide surfaces to form monolayers using tris(pentafluorophenyl)borane (B(C 6 F 5 ) 3 , BCF) catalysis has recently been described. This method, unlike alternative routes to monolayers, produces only unreactive H 2 gas as a byproduct and reaches completion within minutes. We report the use of this selective reaction between surface silanols and hydridosilanes to prepare surface-grafted poly(dimethylsiloxane)s (PDMSs) with various graft architectures that are controlled by the placement of hydridosilane functionality at one end, both ends, or along the chain of PDMS samples of controlled molecular weight. We also report studies of model methylsiloxane monolayers prepared from pentamethyldisiloxane, heptamethyltrisiloxane (two isomers), heptamethylcyclotetrasiloxane, and tris(trimethylsiloxy)silane. These modified silica surfaces with structurally defined methylsiloxane groups are not accessible by conventional silane surface chemistry and proved to be useful in exploring the steric limitations of the reaction. Linear monohydride- and dihydride-terminated PDMS-grafted surfaces exhibit increasing thickness and decreasing contact angle hysteresis with increasing molecular weight up to a particular molecular weight value. Above this value, the hysteresis increases with increasing molecular weight of end-grafted polymers. Poly(hydridomethyl-co-dimethylsiloxane)s with varied hydride content (3-100 mol %) exhibit decreasing thickness, decreasing contact angle, and increasing contact angle hysteresis with increasing hydride content. These observations illustrate the importance of molecular mobility in three-phase contact line dynamics on low-hysteresis surfaces. To calibrate our preparative procedure against both monolayers prepared by conventional approaches as well as the recent reports, a series of trialkylsilane (mostly, n-alkyldimethylsilane) monolayers was prepared to determine the reaction time required to achieve the maximum bonding density using dynamic contact angle analysis. Monolayers prepared from hydridosilanes with BCF catalysis have lower bonding densities than those derived from chlorosilanes, and the reactions are more sensitive to alkyl group sterics. This lower bonding density renders greater flexibility to the n-alkyl groups in monolayers and can decrease the contact angle hysteresis.

A method for the preparation of curcumin by ultrasonic-assisted ammonium sulfate/ethanol aqueous two phase extraction.

PubMed

Xu, Guangkuan; Hao, Changchun; Tian, Suyang; Gao, Feng; Sun, Wenyuan; Sun, Runguang

2017-01-15

This study investigated a new and easy-to-industrialized extracting method for curcumin from Curcuma longa rhizomes using ultrasonic extraction technology combined with ammonium sulfate/ethanol aqueous two-phase system (ATPS), and the preparation of curcumin using the semi-preparative HPLC. The single-factor experiments and response surface methodology (RSM) were utilized to determine the optimal material-solvent ratio, ultrasonic intensity (UI) and ultrasonic time. The optimum extraction conditions were finally determined to be material-solvent rate of 3.29:100, ultrasonic intensity of 33.63W/cm 2 and ultrasonic time of 17min. At these optimum conditions, the extraction yield could reach 46.91mg/g. And the extraction yields of curcumin remained stable in the case of amplification, which indicated that scale-up extraction was feasible and efficient. Afterwards, the semi-preparative HPLC experiment was carried out, in which optimal preparation conditions were elected according to the single factor experiment. The prepared curcumin was obtained and the purity could up to 85.58% by the semi-preparative HPLC. Copyright © 2016 Elsevier B.V. All rights reserved.

Intrinsically water-repellent copper oxide surfaces; An electro-crystallization approach

NASA Astrophysics Data System (ADS)

Akbari, Raziyeh; Ramos Chagas, Gabriela; Godeau, Guilhem; Mohammadizadeh, Mohammadreza; Guittard, Frédéric; Darmanin, Thierry

2018-06-01

Use of metal oxide thin layers is increased due to their good durability under environmental conditions. In this work, the repeatable nanostructured crystalite Cu2O thin films, developed by electrodeposition method without any physical and chemical modifications, demonstrate good hydrophobicity. Copper (I) oxide (Cu2O) layers were fabricated on gold/Si(1 0 0) substrates by different electrodeposition methods i.e. galvanostatic deposition, cyclic voltammetry, and pulse potentiostatic deposition and using copper sulfate (in various concentrations) as a precursor. The greatest crystalline face on prepared Cu2O samples is (1 1 1) which is the most hydrophobic facet of Cu2O cubic structure. Indeed, different crystallite structures such as nanotriangles and truncated octahedrons were formed on the surface for various electrodeposition methods. The increase of the contact angle (θw) measured by the rest time, reaching to about 135°, was seen at different rates and electrodeposition methods. In addition, two-step deposition surfaces were also prepared by applying two of the mentioned methods, alternatively. In general, the morphology of the two-step deposition surfaces showed some changes compared to that of one-step samples, allowing the formation of different crystallite shapes. Moreover, the wettability behavior showd the larger θw of the two-step deposition layers compared to the related one-step deposition layers. Therefore, the highest observed θw was related to the one of two-step deposition layers due to the creation of small octahedral structures on the surface, having narrow and deep valleys. However, there was an exception which was due to the resulted big structures and broad valleys on the surface. So, it is possible to engineer different crystallites shapes using the proposed two-step deposition method. It is expected that hydrophobic crystallite thin films can be used in environmental and electronic applications to save energy and materials properties.

Shape control VO2 nanorods prepared by soft chemistry and electrochemical method

NASA Astrophysics Data System (ADS)

Simo, A.; Sibanyoni, J.; Fuku, X.; Numan, N.; Omorogbe, S.; Maaza, M.

2018-07-01

"Bottom up" approach is of primary interest for chemistry and materials science because the fundamental building blocks are atoms. Thus colloidal chemical synthetic methods can be utilized to prepare uniform nanocrystals with controlled particle size. In the following work of study, thermochromic VO2 nanostructures were prepared by hydrothermal technique soft chemistry. We concentrate on solution phase synthetic methods that enable a proper shape and size control of metal oxide nanocrystals. Their structural properties were studied by Scanning Electron Microscopy (SEM), Fourier Transform IR (FTIR) and Differential Scanning Calorimetry (DSC). It is demonstrated that the surfactant assistance (NaOH) has great influence on the morphology-control of the material. Electrochemical properties of the nanospheres show good stability after 20 cycles and the surface diffusion coefficient was calculated to be 5 × 10-6 cm2 s-1.

Immobilization of glucoamylase on ceramic membrane surfaces modified with a new method of treatment utilizing SPCP-CVD.

PubMed

Ida; Matsuyama; Yamamoto

2000-07-01

Glucoamylase, as a model enzyme, was immobilized on a ceramic membrane modified by surface corona discharge induced plasma chemical process-chemical vapor deposition (SPCP-CVD). Characterizations of the immobilized enzyme were then discussed. Three kinds of ceramic membranes with different amounts of amino groups on the surface were prepared utilizing the SPCP-CVD method. Each with 1-time, 3-times and 5-times surface modification treatments and used for supports in glucoamylase immobilization. The amount of immobilized glucoamylase increased with the increase in the number of surface modification treatments and saturated to a certain maximum value estimated by a two-dimensional random packing. The operational stability of the immobilized glucoamylase also increased with the increase in the number of the surface treatment. It was almost the same as the conventional method, while the activity of immobilized enzyme was higher. The results indicated the possibility of designing the performance of the immobilized enzyme by controlling the amount of amino groups. The above results showed that the completely new surface modification method using SPCP was effective in modifying ceramic membranes for enzyme immobilization.

Preparation and characterization of uniform nanosized cephradine by combination of reactive precipitation and liquid anti-solvent precipitation under high gravity environment.

PubMed

Zhong, Jie; Shen, Zhigang; Yang, Yan; Chen, Jianfeng

2005-09-14

In this work, a novel direct method, which was combined with reactive precipitation and liquid anti-solvent precipitation under high gravity environment, had been developed to prepare nanosized cephradine with narrow particle size distribution. Compared with commercial crude cephradine, the prepared cephradine showed a significant decrease in particle size, a significant increase in the specific surface area and shorter dissolving time when used for injection. The characteristic particle size was between 200-400 nm. The specific surface area increased from 2.95 to 10.87 m2/g after micronization. When the amount of L-arginin decreased from 0.25 to 0.18 g, the mixture of nanosized cephradine and L-arginine could still dissolve in 1 min. The X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) analysis indicated that the physical characteristics and molecular states remained unchanged after the recrystallization process. This method had potential application in industrial fields because of its low cost, efficient processing and the ease of scaling-up.

Mesoporous wormholelike carbon with controllable nanostructure for lithium ion batteries application

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

Yang, Xiaoqing, E-mail: yxq-886@163.com; Li, Xinxi; Li, Zhenghui

2015-06-15

Highlights: • Wormholelike carbon (WMC) with controllable nanostructure is prepared by sol–gel method. • The reversible capacity of WMC is much higher than that of many other reported nanocarbons. • The effect of pore diameter on Li storage capacity is investigated. - Abstract: A class of mesoporous wormholelike carbon (WMC) with controllable nanostructure was prepared by sol–gel method and then used as the anode material of lithium-ion batteries. Based on the experimental results, it is found that the nanostructure of the as-prepared WMC plays an important role in the electrochemical performances. A suitable mesopore size is necessary for a highmore » performance carbon-based anode material since it can not only guarantee effective mass transport channels but also provide large surface area. As a result, F30 with a mesopore size of 4.4 nm coupled with high surface area of 1077 m{sup 2} g{sup −1} shows a reversible capacity of 630 mAh g{sup −1}, much higher than commercial graphite and many other reported nanocarbons.« less

The comparison of laser surface designing and pigment printing methods for the product quality

NASA Astrophysics Data System (ADS)

Ozguney, Arif Taner

2007-07-01

Developing new designs by using the computer and transferring the designs that are obtained to textile surfaces will not only increase and facilitate the production in a more practical manner, but also help you create identical designs. This means serial manufacturing of the products at standard quality and increasing their added values. Moreover, creating textile designs using the laser will also contribute to the value of the product as far as the consumer is concerned because it will not cause any wearing off and deformation in the texture of the fabric unlike the other methods. In the system that has been designed, the laser beam at selected wavelength and intensity was directed onto a selected textile surface and a computer-controlled laser beam source was used to change the colour substances on the textile surface. Pigment printing is also used for designing in textile and apparel sector. In this method, designs are transferred to the fabric manually by using dyestuff. In this study, the denim fabric used for the surfacing trial was 100% cotton, with a weft count per centimeter of 20 and a warp count per centimeter of 27, with fabric weight of 458 g/m 2. The first step was to prepare 40 pieces of denim samples, half of which were prepared manually pigment printing and the other half by using the laser beam. After this, some test applications were done. The tensile strength, tensile extension and some fastness values of designed pieces with two methods were compared according to the international standards.

Two-stage preparation of magnetic sorbent based on exfoliated graphite with ferrite phases for sorption of oil and liquid hydrocarbons from the water surface

NASA Astrophysics Data System (ADS)

Pavlova, Julia A.; Ivanov, Andrei V.; Maksimova, Natalia V.; Pokholok, Konstantin V.; Vasiliev, Alexander V.; Malakho, Artem P.; Avdeev, Victor V.

2018-05-01

Due to the macropore structure and the hydrophobic properties, exfoliated graphite (EG) is considered as a perspective sorbent for oil and liquid hydrocarbons from the water surface. However, there is the problem of EG collection from the water surface. One of the solutions is the modification of EG by a magnetic compound and the collection of EG with sorbed oil using the magnetic field. In this work, the method of the two-stage preparation of exfoliated graphite with ferrite phases is proposed. This method includes the impregnation of expandable graphite in the mixed solution of iron (III) chloride and cobalt (II) or nickel (II) nitrate in the first stage and the thermal exfoliation of impregnated expandable graphite with the formation of exfoliated graphite containing cobalt and nickel ferrites in the second stage. Such two-stage method makes it possible to obtain the sorbent based on EG modified by ferrimagnetic phases with high sorption capacity toward oil (up to 45-51 g/g) and high saturation magnetization (up to 42 emu/g). On the other hand, this method allows to produce the magnetic sorbent in a short period of time (up to 10 s) during which the thermal exfoliation is carried out in the air atmosphere.

Nanocrystalline nickel ferrite particles synthesized by non-hydrolytic sol-gel method and their composite with biodegradable polymer.

PubMed

Yin, H; Casey, P S; Chow, G M

2012-11-01

Targeted drug delivery has been one of the most important biomedical applications for magnetic particles. Such applications require magnetic particles to have functionalized surfaces/surface coatings that facilitate their incorporation into a polymer matrix to produce a polymer composite. In this paper, nanocrystalline nickel ferrite particles with an oleic acid surface coating were synthesized using a non-hydrolytic sol-gel method and incorporated into a biodegradable polymer matrix, poly(D,L-lactide) PLA prepared using a double emulsion method. As-synthesized nickel ferrite particles had a multi-crystalline structure with chemically adsorbed oleic acid on their surface. After forming the PLA composite, nickel ferrite particles were encapsulated in PLA microspheres. At low nickel ferrite concentrations, composites showed very similar surface charges to that of PLA. The composites were magnetically responsive and increasing the nickel ferrite concentration was found to increase magnetization of the composite.

A simple method to prepare magnetic modified beer yeast and its application for cationic dye adsorption.

PubMed

Yu, Jun-Xia; Wang, Li-Yan; Chi, Ru-An; Zhang, Yue-Fei; Xu, Zhi-Gao; Guo, Jia

2013-01-01

The purpose of this research is to use a simple method to prepare magnetic modified biomass with good adsorption performances for cationic ions. The magnetic modified biomass was prepared by two steps: (1) preparation of pyromellitic dianhydride (PMDA) modified biomass in N, N-dimethylacetamide solution and (2) preparation of magnetic PMDA modified biomass by a situ co-precipitation method under the assistance of ultrasound irradiation in ammonia water. The adsorption potential of the as-prepared magnetic modified biomass was analyzed by using cationic dyes: methylene blue and basic magenta as model dyes. Optical micrograph and x-ray diffraction analyses showed that Fe(3)O(4) particles were precipitated on the modified biomass surface. The as-prepared biosorbent could be recycled easily by using an applied magnetic field. Titration analysis showed that the total concentration of the functional groups on the magnetic PMDA modified biomass was calculated to be 0.75 mmol g(-1) by using the first derivative method. The adsorption capacities (q(m)) of the magnetic PMDA modified biomass for methylene blue and basic magenta were 609.0 and 520.9 mg g(-1), respectively, according to the Langmuir equation. Kinetics experiment showed that adsorption could be completed within 150 min for both dyes. The desorption experiment showed that the magnetic sorbent could be used repeatedly after regeneration. The as-prepared magnetic modified sorbent had a potential in the dyeing industry wastewater treatment.

An unscaled parameter to measure the order of surfaces: a new surface elaboration to increase cells adhesion.

PubMed

Bigerelle, M; Anselme, K; Dufresne, E; Hardouin, P; Iost, A

2002-08-01

We present a new parameter to quantify the order of a surface. This parameter is scale-independent and can be used to compare the organization of a surface at different scales of range and amplitude. To test the accuracy of this roughness parameter versus a hundred existing ones, we created an original statistical bootstrap method. In order to assess the physical relevance of this new parameter, we elaborated a great number of surfaces with various roughness amplitudes on titanium and titanium-based alloys using different physical processes. Then we studied the influence of the roughness amplitude on in vitro adhesion and proliferation of human osteoblasts. It was then shown that our new parameter best discriminates among the cell adhesion phenomena than others' parameters (Average roughness (Ra em leader )): cells adhere better on isotropic surfaces with a low order, provided this order is quantified on a scale that is more important than that of the cells. Additionally, on these low ordered metallic surfaces, the shape of the cells presents the same morphological aspect as that we can see on the human bone trabeculae. The method used to prepare these isotropic surfaces (electroerosion) could be undoubtedly and easily applied to prepare most biomaterials with complex geometries and to improve bone implant integration. Moreover, the new order parameter we developed may be particularly useful for the fundamental understanding of the mechanism of bone cell installation on a relief and of the formation of bone cell-material interface.

Preparation of 14C-Labeled Sterigmatocystin in Liquid Media

PubMed Central

Hsieh, Dennis P. H.; Yang, Susie L.

1975-01-01

14C-labeled sterigmatocystin was prepared from surface cultures of Aspergillus versicolor A-18074 maintained in liquid media by multiple additions of [1-14C]acetate to the cultures. The highest yield of 7.75 mg/10 ml was found with a sucrose-asparagine-ammonium medium in which more than 3% of the radioactivity of the added [1-14C]acetate was recovered in the purified [ring-14C] sterigmatocystin. The method offers an easy way to prepare 14C-labeled sterigmatocystin for studies of this mycotoxin. PMID:1110489

[Research on the preparative method of Arctigenin].

PubMed

Zhang, Li-Ying; Yang, Yi-Shun; Zhang, Tong; Ding, Yue; Cai, Zhen-Zhen; Tao, Jian-Sheng

2012-03-01

To research on the preparation of Arctigenin in vitro. Took enzyme concentration, time course and substrate concentration as investigation factors, used Box-Behnken design-response surface methodology to optimize the enzyme hydrolysis path of Arctigenin. The best operational path for Arctigenin was as follows: the temperature was 50 degrees C, pH was 4.8, enzyme concentration was 0.44 U/mL, time course was 46.81 min, substrate concentration was 0.29 mg/mL, the conversion rate was 90.94%. This research can be regarded as a referencein preparing Arctigenin in vitro.

Facile synthesis of biocompatible gold nanoparticles with organosilicone-coated surface properties

NASA Astrophysics Data System (ADS)

Xia, Lijin; Yi, Sijia; Lenaghan, Scott C.; Zhang, Mingjun

2012-07-01

In this study, a simple method for one-step synthesis of gold nanoparticles has been developed using an organosilicone surfactant, Silwet L-77, as both a reducing and capping agent. Synthesis of gold nanoparticles using this method is rapid and can be conducted conveniently at ambient temperature. Further refinement of the method, through the addition of sodium hydroxide and/or silver nitrate, allowed fine control over the size of spherical nanoparticles produced. Coated on the surface with organosilicone, the as-prepared gold nanoparticles were biocompatible and stable over the pH range from 5 to 12, and have been proven effective at transportation into MC3T3 osteoblast cells. The proposed method is simple, fast, and can produce size-controlled gold nanoparticles with unique surface properties for biomedical applications.

Selective preparation of hard dental tissue: classical and laser treatments comparison

NASA Astrophysics Data System (ADS)

Dostálova, Tat'jana; Jelínkova, Helena; Němec, Michal; Koranda, Petr; Miyagi, Mitsunobu; Iwai, Katsumasa; Shi, Yi-Wei; Matsuura, Yuji

2006-02-01

For the purpose of micro-selective preparation which is part of the modern dentistry four various methods were examined: ablation by Er:YAG laser radiation (free-running or Q-switching regime), preparation of tissues by ultrasonic round ball tip, and by the classical dental drilling machine using diamond round bur. In the case of Er:YAG laser application the interaction energy 40 mJ in pulse of 200 us yielding to the interaction intensity 62 kW/cm2, and 20 mJ in pulse of 100 ns yielding to the interaction intensity 62 MW/cm2 was used for the case of free running, and Q-switch regime, respectively. For comparisson with the classical methods the ultrasound preparation tip (Sonixflex cariex TC, D - Sonicsys micro) and dental driller together with usual preparation burrs and standard handpiece were used. For the interaction experiment the samples of extracted human teeth and ebony cut into longitudinal sections and polished were used. The thickness of the prepared samples ranged from 5 to 7 mm. The methods were compared from the point of prepared cavity shape (SEM), inner surface, and possibility of selective removal of carries. The composite filling material was used to reconstruct the cavities. The dye penetrating analysis was performed.

A Generic Wet Impregnation Method for Preparing Substrate-Supported Platinum Group Metal and Alloy Nanoparticles with Controlled Particle Morphology.

PubMed

Zhang, Changlin; Oliaee, Shirin Norooz; Hwang, Sang Youp; Kong, Xiangkai; Peng, Zhenmeng

2016-01-13

Mass production of shape-controlled platinum group metal (PGM) and alloy nanoparticles is of high importance for their many fascinating properties in catalysis, electronics, and photonics. Despite of successful demonstrations at milligram scale using wet chemistry syntheses in many fundamental studies, there is still a big gap between the current methods and their real applications due to the complex synthetic procedures, scale-up difficulty, and surface contamination problem of the made particles. Here we report a generic wet impregnation method for facile, surfactant-free, and scalable preparation of nanoparticles of PGMs and their alloys on different substrate materials with controlled particle morphology and clean surface, which bridges the outstanding properties of these nanoparticles to practical important applications. The underlying particle growth and shape formation mechanisms were investigated using a combination of ex situ and in situ characterizations and were attributed to their different interactions with the applied gas molecules.

Eco-friendly aqueous core surface-modified nanocapsules.

PubMed

Carbone, C; Musumeci, T; Lauro, M R; Puglisi, G

2015-01-01

In this work, positively charged nanocapsules have been developed for potential ocular delivery exploiting the deposition of PLA onto the droplet surface of a W/O nanoemulsion prepared by the reversed procedure of the PIT method. PLA in combination with different amounts of various oils and surfactants have been studied in order to select the best formulation for polymeric nanocapsule preparation. The traditional visual observation together with the Turbiscan(®) technology were exploited in order to identify the best combination of polymer/oil for nanocapsule preparation. Two different primary surfactants (Span(®) 60 and Span(®) 80) have been tested to select their influence on the field of existence of the nanoemulsion by the construction of the pseudoternary phase diagrams. Cationic hybrid NC have been prepared by the addition of a coating layer of DDAB. The physico-chemical and morphological properties of all the prepared nanocapsules have been evaluated and compared by PCS, DSC and AFM. Therefore, positively charged nanocapsules can be easily prepared by a simple eco-friendly technique that exploits biocompatible materials avoiding a large input of mechanical energy as a potential ocular delivery systems for hydrophilic compounds or gene materials. Copyright © 2014 Elsevier B.V. All rights reserved.

TRIZ theory in NEA photocathode preparation system

NASA Astrophysics Data System (ADS)

Qiao, Jianliang; Huang, Dayong; Li, Xiangjiang; Gao, Youtang

2016-09-01

The solutions to the engineering problems were provided according to the innovation principle based on the theory of TRIZ. The ultra high vacuum test and evaluation system for the preparation of negative electron affinity (NEA) photocathode has the characteristics of complex structure and powerful functions. Segmentation principle, advance function principle, curved surface principle, dynamic characteristics principle and nested principle adopted by the design of ultra high vacuum test and evaluation system for cathode preparation were analyzed. The applications of the physical contradiction and the substance-field analysis method of the theory of TRIZ in the cathode preparation ultra high vacuum test and evaluation system were discussed.

A freeze-dried injectable form of ibuprofen: development and optimisation using response surface methodology.

PubMed

Kagkadis, K A; Rekkas, D M; Dallas, P P; Choulis, N H

1996-01-01

In this study a complex of Ibuprofen and b-Hydroxypropylcyclodextrin was prepared employing a freeze drying method. The production parameters and the final specifications of this product were optimized by using response surface methodology. The results show that the freeze dried complex meets the requirements for solubility to be considered as a possible injectable form.

Laser-induced surface modification of biopolymers – micro/nanostructuring and functionalization

NASA Astrophysics Data System (ADS)

Stankova, N. E.; Atanasov, P. A.; Nedyalkov, N. N.; Tatchev, Dr; Kolev, K. N.; Valova, E. I.; Armyanov, St. A.; Grochowska, K.; Śliwiński, G.; Fukata, N.; Hirsch, D.; Rauschenbach, B.

2018-03-01

The medical-grade polydimethylsiloxane (PDMS) elastomer is a widely used biomaterial in medicine for preparation of high-tech devices because of its remarkable properties. In this paper, we present experimental results on surface modification of PDMS elastomer by using ultraviolet, visible, and near-infrared ns-laser system and investigation of the chemical composition and the morphological structure inside the treated area in dependence on the processing parameters – wavelength, laser fluence and number of pulses. Remarkable chemical transformations and changes of the morphological structure were observed, resulting in the formation of a highly catalytically active surface, which was successfully functionalized via electroless Ni and Pt deposition by a sensitizing-activation free process. The results obtained are very promising in view of applying the methods of laser-induced micro- and nano-structuring and activation of biopolymers’ surface and further electroless metal plating to the preparation of, e.g., multielectrode arrays (MEAs) devices in neural and muscular surface interfacing implantable systems.

Comparison of Zirconium Phosphonate-Modified Surfaces for Immobilizing Phosphopeptides and Phosphate-Tagged Proteins.

PubMed

Forato, Florian; Liu, Hao; Benoit, Roland; Fayon, Franck; Charlier, Cathy; Fateh, Amina; Defontaine, Alain; Tellier, Charles; Talham, Daniel R; Queffélec, Clémence; Bujoli, Bruno

2016-06-07

Different routes for preparing zirconium phosphonate-modified surfaces for immobilizing biomolecular probes are compared. Two chemical-modification approaches were explored to form self-assembled monolayers on commercially available primary amine-functionalized slides, and the resulting surfaces were compared to well-characterized zirconium phosphonate monolayer-modified supports prepared using Langmuir-Blodgett methods. When using POCl3 as the amine phosphorylating agent followed by treatment with zirconyl chloride, the result was not a zirconium-phosphonate monolayer, as commonly assumed in the literature, but rather the process gives adsorbed zirconium oxide/hydroxide species and to a lower extent adsorbed zirconium phosphate and/or phosphonate. Reactions giving rise to these products were modeled in homogeneous-phase studies. Nevertheless, each of the three modified surfaces effectively immobilized phosphopeptides and phosphopeptide tags fused to an affinity protein. Unexpectedly, the zirconium oxide/hydroxide modified surface, formed by treating the amine-coated slides with POCl3/Zr(4+), afforded better immobilization of the peptides and proteins and efficient capture of their targets.

Influence of acid chain length on the properties of TiO2 prepared by sol-gel method and LC-MS studies of methylene blue photodegradation.

PubMed

Bakre, Pratibha V; Volvoikar, Prajesh S; Vernekar, Amit A; Tilve, S G

2016-07-15

Nano-sized titanium dioxide photocatalysts were synthesized by hybrid hydrolytic nonhydrolytic sol-gel method using aliphatic organic acid templates to study the effect of chain length on their properties. X-ray diffraction pattern indicated crystalline anatase phase. The Barrett-Joyner-Halenda surface area measurement gave surface area ranging from 98.4 to 205.5m(2)/g and was found to be dependent on the chain length of the aliphatic acid. The longer chain acids rendered the material with high surface area. The organic acids acted as bidentate ligand and a surfactant in controlling the size and the mesoporosity. The size of the TiO2 nanoparticulate was found to be in the range of 10-18nm. The catalyst prepared by employing long chain acids octanoic acid and palmitic acid had smaller size, narrow pore radius, higher surface area and showed better photocatalytic activity than the commercially available Degussa P25 catalyst for the degradation of methylene blue dye. A new intermediate was identified by tandem liquid chromatography mass spectrometry studies during the degradation of methylene blue solution. Copyright © 2016 Elsevier Inc. All rights reserved.

Microwave-induced activation of additional active edge sites on the MoS2 surface for enhanced Hg0 capture

NASA Astrophysics Data System (ADS)

Zhao, Haitao; Mu, Xueliang; Yang, Gang; Zheng, Chengheng; Sun, Chenggong; Gao, Xiang; Wu, Tao

2017-10-01

In recent years, significant effort has been made in the development of novel materials for the removal of mercury from coal-derived flue gas. In this research, microwave irradiation was adopted to induce the creation of additional active sites on the MoS2 surface. The results showed that Hg0 capture efficiency of the adsorbent containing MoS2 nanosheets being microwave treated was as high as 97%, while the sample prepared via conventional method only showed an efficiency of 94% in its first 180 min testing. After the adsorbent was treated by microwave irradiation for 3 more times, its mercury removal efficiency was still noticeably higher than that of the sample prepared via conventional method. Characterization of surface structure of the MoS2 containing material together with DFT study further revealed that the (001) basal planes of MoS2 crystal structure were cracked into (100) edge planes (with an angle of approximately 75°) under microwave treatment, which subsequently resulted in the formation of additional active edge sites on the MoS2 surface and led to the improved performance on Hg0 capture.

Method of preparing a negative electrode including lithium alloy for use within a secondary electrochemical cell

DOEpatents

Tomczuk, Zygmunt; Olszanski, Theodore W.; Battles, James E.

1977-03-08

A negative electrode that includes a lithium alloy as active material is prepared by briefly submerging a porous, electrically conductive substrate within a melt of the alloy. Prior to solidification, excess melt can be removed by vibrating or otherwise manipulating the filled substrate to expose interstitial surfaces. Electrodes of such as solid lithium-aluminum filled within a substrate of metal foam are provided.

Preparation, Modification, Characterization, and Biosensing Application of Nanoporous Gold Using Electrochemical Techniques

PubMed Central

Neupane, Dharmendra; Nepal, Bishal; Mikhaylov, Vasilii; Stine, Keith J.

2018-01-01

Nanoporous gold (np-Au), because of its high surface area-to-volume ratio, excellent conductivity, chemical inertness, physical stability, biocompatibility, easily tunable pores, and plasmonic properties, has attracted much interested in the field of nanotechnology. It has promising applications in the fields of catalysis, bio/chemical sensing, drug delivery, biomolecules separation and purification, fuel cell development, surface-chemistry-driven actuation, and supercapacitor design. Many chemical and electrochemical procedures are known for the preparation of np-Au. Recently, researchers are focusing on easier and controlled ways to tune the pores and ligaments size of np-Au for its use in different applications. Electrochemical methods have good control over fine-tuning pore and ligament sizes. The np-Au electrodes that are prepared using electrochemical techniques are robust and are easier to handle for their use in electrochemical biosensing. Here, we review different electrochemical strategies for the preparation, post-modification, and characterization of np-Au along with the synergistic use of both electrochemistry and np-Au for applications in biosensing. PMID:29547580

Preparation, Modification, Characterization, and Biosensing Application of Nanoporous Gold Using Electrochemical Techniques.

PubMed

Bhattarai, Jay K; Neupane, Dharmendra; Nepal, Bishal; Mikhaylov, Vasilii; Demchenko, Alexei V; Stine, Keith J

2018-03-16

Nanoporous gold (np-Au), because of its high surface area-to-volume ratio, excellent conductivity, chemical inertness, physical stability, biocompatibility, easily tunable pores, and plasmonic properties, has attracted much interested in the field of nanotechnology. It has promising applications in the fields of catalysis, bio/chemical sensing, drug delivery, biomolecules separation and purification, fuel cell development, surface-chemistry-driven actuation, and supercapacitor design. Many chemical and electrochemical procedures are known for the preparation of np-Au. Recently, researchers are focusing on easier and controlled ways to tune the pores and ligaments size of np-Au for its use in different applications. Electrochemical methods have good control over fine-tuning pore and ligament sizes. The np-Au electrodes that are prepared using electrochemical techniques are robust and are easier to handle for their use in electrochemical biosensing. Here, we review different electrochemical strategies for the preparation, post-modification, and characterization of np-Au along with the synergistic use of both electrochemistry and np-Au for applications in biosensing.

Gelatin based bio-films prepared from grey triggerfish' skin influenced by enzymatic pretreatment.

PubMed

Souissi, Nabil; Abdelhedi, Ola; Mbarek, Aïcha; Kammoun, Wassim; Kechaou, Hela; Nasri, Moncef

2017-12-01

Gelatins from grey triggerfish skin were extracted with different methods. The treatment by pepsin (PG) improved the yield of extraction when compared with untreated gelatin (UG) and acidic gelatin (AG). The outputs of gelatins AG, UG and PG, obtained respectively, with acitic acid, glycine buffer and glycine buffer added with 5U of pepsin/g of the skin beforehand treated by alkali, were 6.9%, 7.9% and 9.7%, respectively. The enzymatic treatment of the alkali-pretreated skin of grey triggerfish altered the electrophoresis profile, biophysical, gellification, rheological and thermal properties of the prepared gelatins extracted under acidic condition. However, the untreated gelatin obtained without pepsin exhibited the highest transition and enthaply temperatures. In addition, the properties of the prepared films were interconnected to their microstructure as demonstrated by scanning electron microscopy. Furthermore, films with PG and UG had a regular surface and a more condensed structure, whereas films prepared with AG had rougher surface. Copyright © 2017 Elsevier B.V. All rights reserved.

Degradation prediction model and stem cell growth of gelatin-PEG composite hydrogel.

PubMed

Zhou, Nan; Liu, Chang; Lv, Shijie; Sun, Dongsheng; Qiao, Qinglong; Zhang, Rui; Liu, Yang; Xiao, Jing; Sun, Guangwei

2016-12-01

Gelatin hydrogel has great potential in regenerative medicine. The degradation of gelatin hydrogel is important to control the release profile of encapsulated biomolecules and regulate in vivo tissue repair process. As a plasticizer, PEG can significantly improve the mechanical property of gelatin hydrogel. However, how preparation parameters affect the degradation rate of gelatin-PEG composite hydrogel is still not clear. In this study, the significant effect factor, glutaraldehyde (GA) concentration, was confirmed by means of Plackett-Burman method. Then a mathematical model was built to predict the degradation rate of composite hydrogels under different preparation conditions using the response surface method (RSM), which was helpful to prepare the certain composite hydrogel with desired degradation rate. In addition, it was found that gelatin-PEG composite hydrogel surface well supported the adhesion and growth of human mesenchymal stem cells (MSCs). Moreover, PEG concentration not only could adjust hydrogel degradation more subtly, but also might increase the cross-linking degree and affect the cell migration. Therefore, these results would be useful to optimize the preparation of gelatin-PEG composite hydrogel for drug delivery or tissue engineering. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 3149-3156, 2016. © 2016 Wiley Periodicals, Inc.

Poly arginine-graphene quantum dots as a biocompatible and non-toxic nanocomposite: Layer-by-layer electrochemical preparation, characterization and non-invasive malondialdehyde sensory application in exhaled breath condensate.

PubMed

Hasanzadeh, Mohammad; Mokhtari, Fozieh; Shadjou, Nasrin; Eftekhari, Aziz; Mokhtarzadeh, Ahad; Jouyban-Gharamaleki, Vahid; Mahboob, Soltanali

2017-06-01

This study reports on the electropolymerization of a low toxic and biocompatible polymer with entitle poly arginine-graphene quantum dots (PARG-GQDs) as a novel strategy for surface modification of glassy carbon (GC) surface and preparation a new interface for biomedical application. The fabrication of PARG-GQDs on GCE was performed using Layer-by-layer regime. Scanning electron microscopy (SEM) was confirmed dispersion of GQDs on the surface of PARG which lead to increase of surface coverage of PARG. The redox behavior of prepared sensor was then characterized by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and chronoamperometry (CHA), square wave voltammetry (SWV), linear sweep voltammetry (LSV). The electroactivity of PARG-GQDs coating towards detection and determination of malondialdehyde (MDA) as one of the most common biomarkers of oxidative stress, was then studied. Then, application of prepared sensor for the detection of MDA in exhaled breath condensate (EBC) is described. Electrochemical based sensor shows the lower limit of quantification (LLOQ) were 0.329nanomolar. This work is the first report on the integration of GQDs to poly amino acids. Further development can lead to monitoring of MDA or other exhaled breath biomarkers by GQDs functionalized poly amino acids in EBC using electrochemical methods. Copyright © 2017. Published by Elsevier B.V.

Evaluation of intranuclear BrdU detection procedures for use in multicolor flow cytometry*

PubMed Central

Rothaeusler, Kristina; Baumgarth, Nicole

2010-01-01

Background Measurement of cell proliferation via BrdU incorporation in combination with multicolor cell surface staining would facilitate studies on cell subsets that require multiple markers for their identification. However, the extent to which the often harsh cell preparation procedures required affect the staining quality of more recently developed fluorescent dyes has not been assessed. Methods Three cell preparation protocols for BrdU measurement were compared for their ability to maintain fluorescent surface staining and scatter parameters of in vivo BrdU-labeled cells by flow cytometry. A 10-color fluorescent panel was developed to test the quality of surface staining following cell treatment and the ability to perform BrdU measurements on even small B lymphocyte subsets. Results All cell preparation procedures affected the quality of fluorescent and/or scatter parameters to varying degrees. Paraformaldehyde / saponin-based procedures preserved sufficient fluorescent surface staining to determine BrdU incorporation rates among all splenic B cell subsets, including B-1a cells, which constitute roughly 0.5% of cells. Turnover rates of B-1a cells were similar to immature B cells and higher than those of the other mature B cell subsets. Conclusion Paraformaldehyde / saponin-based cell preparation procedures facilitate detailed cell turnover studies on small cell subsets in vivo, revealing new functional information on rare cell populations. PMID:16538653

From honeycomb- to microsphere-patterned surfaces of poly(lactic acid) and a starch-poly(lactic acid) blend via the breath figure method.

PubMed

Duarte, Ana Rita C; Maniglio, Devid; Sousa, Nuno; Mano, João F; Reis, Rui L; Migliaresi, Claudio

2017-01-26

This study investigated the preparation of ordered patterned surfaces and/or microspheres from a natural-based polymer, using the breath figure and reverse breath figure methods. Poly(D,L-lactic acid) and starch poly(lactic acid) solutions were precipitated in different conditions - namely, polymer concentration, vapor atmosphere temperature and substrate - to evaluate the effect of these conditions on the morphology of the precipitates obtained. The possibility of fine-tuning the properties of the final patterns simply by changing the vapor atmosphere was also demonstrated here using a range of compositions of the vapor phase. Porous films or discrete particles are formed when the differences in surface tension determine the ability of polymer solution to surround water droplets or methanol to surround polymer droplets, respectively. In vitro cytotoxicity was assessed applying a simple standard protocol to evaluate the possibility to use these materials in biomedical applications. Moreover, fluorescent microscopy images showed a good interaction of cells with the material, which were able to adhere on the patterned surfaces after 24 hours in culture. The development of patterned surfaces using the breath figure method was tested in this work for the preparation of both poly(lactic acid) and a blend containing starch and poly(lactic acid). The potential of these films to be used in the biomedical area was confirmed by a preliminary cytotoxicity test and by morphological observation of cell adhesion.

Water repellent porous silica films by sol-gel dip coating method.

PubMed

Rao, A Venkateswara; Gurav, Annaso B; Latthe, Sanjay S; Vhatkar, Rajiv S; Imai, Hiroaki; Kappenstein, Charles; Wagh, P B; Gupta, Satish C

2010-12-01

The wetting of solid surfaces by water droplets is ubiquitous in our daily lives as well as in industrial processes. In the present research work, water repellent porous silica films are prepared on glass substrate at room temperature by sol-gel process. The coating sol was prepared by keeping the molar ratio of methyltriethoxysilane (MTES), methanol (MeOH), water (H(2)O) constant at 1:12.90:4.74, respectively, with 2M NH(4)OH throughout the experiments and the molar ratio (M) of MTES/Ph-TMS was varied from 0 to 0.22. A simple dip coating technique is adopted to coat silica films on the glass substrates. The static water contact angle as high as 164° and water sliding angle as low as 4° was obtained for silica film prepared from M=0.22. The surface morphological studies of the prepared silica film showed the porous structure with pore sizes typically ranging from 200nm to 1.3μm. The superhydrophobic silica films prepared from M=0.22 retained their superhydrophobicity up to a temperature of 285°C and above this temperature the films became superhydrophilic. The porous and water repellent silica films are prepared by proper alteration of the Ph-TMS in the coating solution. The prepared silica films were characterized by surface profilometer, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier Transform Infrared (FT-IR) spectroscopy, humidity tests, chemical aging tests, static and dynamic water contact angle measurements. Copyright © 2010 Elsevier Inc. All rights reserved.

Improvement in the amine glass platform by bubbling method for a DNA microarray

PubMed Central

Jee, Seung Hyun; Kim, Jong Won; Lee, Ji Hyeong; Yoon, Young Soo

2015-01-01

A glass platform with high sensitivity for sexually transmitted diseases microarray is described here. An amino-silane-based self-assembled monolayer was coated on the surface of a glass platform using a novel bubbling method. The optimized surface of the glass platform had highly uniform surface modifications using this method, as well as improved hybridization properties with capture probes in the DNA microarray. On the basis of these results, the improved glass platform serves as a highly reliable and optimal material for the DNA microarray. Moreover, in this study, we demonstrated that our glass platform, manufactured by utilizing the bubbling method, had higher uniformity, shorter processing time, lower background signal, and higher spot signal than the platforms manufactured by the general dipping method. The DNA microarray manufactured with a glass platform prepared using bubbling method can be used as a clinical diagnostic tool. PMID:26468293

Improvement in the amine glass platform by bubbling method for a DNA microarray.

PubMed

Jee, Seung Hyun; Kim, Jong Won; Lee, Ji Hyeong; Yoon, Young Soo

2015-01-01

A glass platform with high sensitivity for sexually transmitted diseases microarray is described here. An amino-silane-based self-assembled monolayer was coated on the surface of a glass platform using a novel bubbling method. The optimized surface of the glass platform had highly uniform surface modifications using this method, as well as improved hybridization properties with capture probes in the DNA microarray. On the basis of these results, the improved glass platform serves as a highly reliable and optimal material for the DNA microarray. Moreover, in this study, we demonstrated that our glass platform, manufactured by utilizing the bubbling method, had higher uniformity, shorter processing time, lower background signal, and higher spot signal than the platforms manufactured by the general dipping method. The DNA microarray manufactured with a glass platform prepared using bubbling method can be used as a clinical diagnostic tool.

Photochemical preparation of sub-wavelength heterogeneous laser-induced periodic surface structures.

PubMed

Kim, Hee-Cheol; Reinhardt, Hendrik; Hillebrecht, Pierre; Hampp, Norbert A

2012-04-17

Laser-induced periodic surface structures (LIPSS) are a phenomenon caused by interaction of light with solid surfaces. We present a photochemical concept which uses LIPSS-related light intensity patterns for the generation of heterogeneous nanostructures. The process facilitates arbitrary combinations of substrate and LIPSS-pattern materials. An efficient method for the generation of organometallic hybrid-nanowire arrays on porous anodic aluminum oxide is demonstrated. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Shear test of composite bonded to dentin: Er:YAG laser versus dental handpiece preparations

NASA Astrophysics Data System (ADS)

Visuri, Steven R.; Gilbert, Jeremy L.; Walsh, Joseph T., Jr.; Wigdor, Harvey A.

1995-05-01

The erbium:YAG laser coupled with a cooling stream of water appears to be an effective means of removing dental hard tissues. However, before the procedure is deemed clinically viable, there are several important issues of safety and efficacy that need to be explored. In this study we investigated the surface that remains following laser ablation of dentin and compared the results to the use of a dental handpiece. Specifically, we studied the effect the laser radiation had on the bonding of composite to dentin. The crowns of extracted human molars were removed revealing the underlying dentin. An additional thickness of material was removed with either a dental handpiece or an Er:YAG laser by raster scanning the samples under a fixed handpiece or laser. Comparable surface roughnesses were achieved. A cylinder of composite was bonded onto the prepared surfaces following the manufacturer's directions. The dentin-composite bond was then shear stressed to failure on a universal testing apparatus and the maximum load recorded. Preliminary results indicated that laser irradiated samples had improved bond strengths. SEM photographs of the surfaces were also taken to compare the two methods of tooth preparation.

Robust superhydrophobic needle-like nanostructured ZnO surfaces prepared without post chemical-treatment

NASA Astrophysics Data System (ADS)

Velayi, Elmira; Norouzbeigi, Reza

2017-12-01

Robust superhydrophobic ZnO surfaces with micro/nano hybrid hierarchical structures were synthesized on the stainless steel mesh by a facile single-step chemical bath deposition (CBD) method without using further low surface energy materials. The Taguchi L16 experimental design was applied to evaluate the effects of reaction time, type and concentration of the additive, type of the chelating agent, and the molar ratio of the chelating agent to the initial zinc (II) ions. The prepared sample at the optimal conditions exhibited a sustainable and time-independent superhydrophobic behavior with the water contact angle (WCA) of 162.8° ± 2.5° and contact angle hysteresis (CAH) of 1.8° ± 0.5°. The XRD, SEM, TEM and FTIR analyses were used to characterize the prepared samples. Surface characterization using scanning electron microscopy (SEM) indicated accumulation of micro/nano branched ZnO needles on the substrate with the average diameters of ∼85 nm. After 20 abrasion cycles the optimum sample indicated an excellent mechanical robustness via exposure to the pressure of 4.7 kPa. A suitable chemical resistance to the acidic and basic droplets with the pH range of 4 and 9 was observed.

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.

Surface-imprinted microspheres prepared by a template-oriented method for the chiral separation of amlodipine.

PubMed

Lai, Shenzhi; Ouyang, Xiaoli; Cai, Changqun; Xu, Wensheng; Chen, Chunyan; Chen, Xiaoming

2017-05-01

The surface imprinting technique has been developed to overcome the mass-transfer difficulty, but the utilization ratio of template molecules in the imprinting procedure still remains a challengeable task to be improved. In this work, specifically designed surface-imprinted microspheres were prepared by a template-oriented method for enantioseparation of amlodipine besylate. Submicron mesoporous silica microspheres were surface-modified with double bonds, followed by polymerizing methacrylic acid to generate carboxyl modified mesoporous silica microspheres (PMAA@SiO 2 ). Afterwards, PMAA@SiO 2 was densely adsorbed with (S)-amlodipine molecules to immobilize template molecules through multiple hydrogen bonding interactions. Then surface molecular imprinting was carried out by cross-linking the carboxyl group of PMAA@SiO 2 with ethylene glycol diglycidyl ether. The surface-imprinted microspheres showed fast binding kinetics of only 20 min for equilibrium adsorption, and the saturation adsorption capacity reached 137 mg/g. The imprinted materials displayed appreciable chiral separation ability when used as column chromatography for enantioseparation of amlodipine from amlodipine besylate, and the enantiomeric excess of (S)-amlodipine reached 13.8% with only 2.3 cm column length by no extra chiral additives. Besides, the imprinted materials exhibited excellent reusability, and this allows the potential application for amplification production of amlodipine enantiomer. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Transfer Printing Method to Obtain Polarized Light Emission in Organic Light-Emitting Device

NASA Astrophysics Data System (ADS)

Noh, Hee Yeon; Park, Chang-sub; Park, Ji-Sub; Kang, Shin-Won; Kim, Hak-Rin

2012-06-01

We demonstrate a transfer printing method to obtain polarized light emission in organic light-emitting devices (OLEDs). On a rubbed self-assembled monolayer (SAM), a spin-coated liquid crystalline light-emissive polymer is aligned along the rubbing direction because of the anisotropic interfacial intermolecular interaction. Owing to the low surface energy of the SAM surface, the light-emissive layer was easily transferred to a patterned poly(dimethylsiloxane) (PDMS) stamp surface without degrading the ordering. Finally, a polarized light-emissive OLED device was prepared by transferring the patterned light-emissive layer to the charge transport layer of the OLED structure.

Growth of coincident site lattice matched semiconductor layers and devices on crystalline substrates

DOEpatents

Norman, Andrew G; Ptak, Aaron J

2013-08-13

Methods of fabricating a semiconductor layer or device and said devices are disclosed. The methods include but are not limited to providing a substrate having a crystalline surface with a known lattice parameter (a). The method further includes growing a crystalline semiconductor layer on the crystalline substrate surface by coincident site lattice matched epitaxy, without any buffer layer between the crystalline semiconductor layer and the crystalline surface of the substrate. The crystalline semiconductor layer will be prepared to have a lattice parameter (a') that is related to the substrate lattice parameter (a). The lattice parameter (a') maybe related to the lattice parameter (a) by a scaling factor derived from a geometric relationship between the respective crystal lattices.

Characterization of perovskite film prepared by pulsed laser deposition on ferritic stainless steel using microscopic and optical methods

NASA Astrophysics Data System (ADS)

Durda, E.; Jaglarz, J.; Kąc, S.; Przybylski, K.; El Kouari, Y.

2016-06-01

The perovskite La0.6Sr0.4Co0.2Fe0.8O3-δ (LSCF48) film was deposited on Crofer 22 APU ferritic stainless steel by pulsed laser deposition (PLD). Morphological studies of the sample were performed using scanning electron microscopy (SEM) and atomic force microscopy (AFM). Information about film thickness and surface topography of the film and the steel substrate were obtained using following optical methods: spectroscopic ellipsometry (SE), bidirectional reflection distribution function (BRDF) and total integrated reflectometry (TIS). In particular, the BRDF study, being complementary to atomic force microscopy, yielded information about surface topography. Using the previously mentioned methods, the following statistic surface parameters were determined: root-mean square (rms) roughness and autocorrelation length by determining the power spectral density (PSD) function of surface irregularities.

Nanoindentation size effects in wood

Treesearch

Joseph E. Jakes; Donald S. Stone; Charles R. Frihart

2007-01-01

The purpose of this work was to test some of the assumptions underlying methods currently employed to investigate nanoindentation properties of wood. We examined whether hardness and modulus depend on load. We employed a surface preparation technique that minimizes alterations of cell wall properties. Areas were determined using both (a) Oliver-Pharr method and (b) a...

Gas-tungsten arc welding of aluminum alloys

DOEpatents

Frye, L.D.

1982-03-25

The present invention is directed to a gas-tungsten arc welding method for joining together structures formed of aluminum alloy with these structures disposed contiguously to a heat-damagable substrate of a metal dissimilar to the aluminum alloy. The method of the present invention is practiced by diamond machining the fay surfaces of the aluminum alloy structures to profice a mirror finish thereon having a surface roughness in the order of about one microinch. The fay surface are aligned and heated sufficiently by the tungsten electrode to fuse the aluminum alloy continguous to the fay surfaces to effect the weld joint. The heat input used to provide an oxide-free weld is significantly less than that required if the fay surfaces were prepared by using conventional chemical and mechanical practices.

Preparation of superhydrophobic copper surface by a novel silk-screen printing aided electrochemical machining method

NASA Astrophysics Data System (ADS)

Yan, X. Y.; Chen, G. X.; Liu, J. W.

2018-03-01

A kind of superhydrophobic copper surface with micro-nanocomposite structure has been successfully fabricated by employing a silk-screen printing aided electrochemical machining method. At first silk-screen printing technology has been used to form a column point array mask, and then the microcolumn array would be fabricated by electrochemical machining (ECM) effect. In this study, the drop contact angles have been studied and scanning electron microscopy (SEM) has been used to study the surface characteristic of the workpiece. The experiment results show that the micro-nanocomposite structure with cylindrical array can be successfully fabricated on the metal surface. And the maximum contact angle is 151° when the fluoroalkylsilane ethanol solution was used to modify the machined surface in this study.

Development of an Aerosol Surface Inoculation Method for Bacillus Spores ▿

PubMed Central

Lee, Sang Don; Ryan, Shawn P.; Snyder, Emily Gibb

2011-01-01

A method was developed to deposit Bacillus subtilis spores via aerosolization onto various surface materials for biological agent decontamination and detection studies. This new method uses an apparatus coupled with a metered dose inhaler to reproducibly deposit spores onto various surfaces. A metered dose inhaler was loaded with Bacillus subtilis spores, a surrogate for Bacillus anthracis. Five different material surfaces (aluminum, galvanized steel, wood, carpet, and painted wallboard paper) were tested using this spore deposition method. This aerosolization method deposited spores at a concentration of more than 107 CFU per coupon (18-mm diameter) with less than a 50% coefficient of variation, showing that the aerosolization method developed in this study can deposit reproducible numbers of spores onto various surface coupons. Scanning electron microscopy was used to probe the spore deposition patterns on test coupons. The deposition patterns observed following aerosol impaction were compared to those of liquid inoculation. A physical difference in the spore deposition patterns was observed to result from the two different methods. The spore deposition method developed in this study will help prepare spore coupons via aerosolization fast and reproducibly for bench top decontamination and detection studies. PMID:21193670

Development of an aerosol surface inoculation method for bacillus spores.

PubMed

Lee, Sang Don; Ryan, Shawn P; Snyder, Emily Gibb

2011-03-01

A method was developed to deposit Bacillus subtilis spores via aerosolization onto various surface materials for biological agent decontamination and detection studies. This new method uses an apparatus coupled with a metered dose inhaler to reproducibly deposit spores onto various surfaces. A metered dose inhaler was loaded with Bacillus subtilis spores, a surrogate for Bacillus anthracis. Five different material surfaces (aluminum, galvanized steel, wood, carpet, and painted wallboard paper) were tested using this spore deposition method. This aerosolization method deposited spores at a concentration of more than 10(7) CFU per coupon (18-mm diameter) with less than a 50% coefficient of variation, showing that the aerosolization method developed in this study can deposit reproducible numbers of spores onto various surface coupons. Scanning electron microscopy was used to probe the spore deposition patterns on test coupons. The deposition patterns observed following aerosol impaction were compared to those of liquid inoculation. A physical difference in the spore deposition patterns was observed to result from the two different methods. The spore deposition method developed in this study will help prepare spore coupons via aerosolization fast and reproducibly for bench top decontamination and detection studies.

A convenient method for synthesis of glyconanoparticles for colorimetric measuring carbohydrate-protein interactions

PubMed Central

Chuang, Yen-Jun; Zhou, Xichun; Pan, Zhengwei; Turchi, Craig

2009-01-01

Carbohydrate functionalized nanoparticles, i.e., the glyconanoparticles, have wide application ranging from studies of carbohydrate-protein interactions, in vivo cell imaging, biolabeling, etc. Currently reported methods for preparation of glyconanoaprticles require multi-step modifications of carbohydrates moieties to conjugate to nanoparticle surface. However, the required synthetic manipulations are difficult and time consuming. We report herewith a simple and versatile method for preparing glyconanoparticles. This method is based on the utilization of clean and convenient microwave irradiation energy for one-step, site-specific conjugation of unmodified carbohydrates onto hydrazide-functionalized Au nanoparticles. A colorimetric assay that utilizes the ensemble of gold glyconanoparticles and Concanavalin A (ConA) was also presented. This feasible assay system was developed to analyze multivalent interactions and to determine the dissociation constant (Kd) for five kind of Au glyconanoparticles with lectin. Surface plasmon changes of the Au glyconanparticles as a function of lectin-carbohydrate interactions were measured and the dissociation constants were determined based on non-linear curve fitting. The strength of the interaction of carbohydrates with ConA was found to be as follows: Maltose > Mannose > Glucose > Lactose > MAN5. PMID:19698698

Preparation and characterization of bio-nanocomposite films of agar and silver nanoparticles: laser ablation method.

PubMed

Rhim, Jong-Whan; Wang, Long-Feng; Lee, Yonghoon; Hong, Seok-In

2014-03-15

Silver nanoparticles (AgNPs) were prepared by a laser ablation method and composite films with the AgNPs and agar were prepared by solvent casting method. UV-vis absorbance test and transmission electron microscopy (TEM) analysis results revealed that non-agglomerated spherical AgNPs were formed by the laser ablation method. The surface color of the resulting agar/AgNPs films exhibited the characteristic plasmonic effect of the AgNPs with the maximum absorption peaks of 400-407 nm. X-ray diffraction (XRD) test results also exhibited characteristic AgNPs crystals with diffraction peaks observed at 2θ values of 38.39°, 44.49°, and 64.45°, which were corresponding to (111), (200), and (220) crystallographic planes of face-centered cubic (fcc) silver crystals, respectively. Thermogravimetric analysis (TGA) results showed that thermal stability of the agar/AgNPs composite films was increased by the inclusion of metallic silver. Water vapor barrier properties and surface hydrophobicity of the agar/AgNPs films increased slightly with the increase in AgNPs content but they were not statistically significant (p>0.05), while mechanical strength and stiffness of the composite films decreased slightly (p<0.05). The agar/AgNPs films exhibited distinctive antimicrobial activity against both Gram-positive (Listeria monocytogenes) and Gram-negative (Escherichia coli O157:H7) bacterial pathogens. Copyright © 2014 Elsevier Ltd. All rights reserved.

Validation of an automated fluorescein method for determining bromide in water

USGS Publications Warehouse

Fishman, M. J.; Schroder, L.J.; Friedman, L.C.

1985-01-01

Surface, atmospheric precipitation and deionized water samples were spiked with ??g l-1 concentrations of bromide, and the solutions stored in polyethylene and polytetrafluoroethylene bottles. Bromide was determined periodically for 30 days. Automated fluorescein and ion chromatography methods were used to determine bromide in these prepared samples. Analysis of the data by the paired t-test indicates that the two methods are not significantly different at a probability of 95% for samples containing from 0.015 to 0.5 mg l-1 of bromide. The correlation coefficient for the same sets of paired data is 0.9987. Recovery data, except for the surface water samples to which 0.005 mg l-1 of bromide was added, range from 89 to 112%. There appears to be no loss of bromide from solution in either type of container.Surface, atmospheric precipitation and deionized water samples were spiked with mu g l** minus **1 concentrations of bromide, and the solutions stored in polyethylene and polytetrafluoroethylene bottles. Bromide was determined periodically for 30 days. Automated fluorescein and ion chromatography methods were used to determine bromide in these prepared samples. Analysis of the data by the paired t-test indicates that the two methods are not significantly different at a probability of 95% for samples containing from 0. 015 to 0. 5 mg l** minus **1 of bromide. The correlation coefficient for the same sets of paired data is 0. 9987. Recovery data, except for the surface water samples to which 0. 005 mg l** minus **1 of bromide was added, range from 89 to 112%. Refs.

Method for preparing ultraflat, atomically perfect areas on large regions of a crystal surface by heteroepitaxy deposition

DOEpatents

El Gabaly, Farid; Schmid, Andreas K.

2013-03-19

A novel method of forming large atomically flat areas is described in which a crystalline substrate having a stepped surface is exposed to a vapor of another material to deposit a material onto the substrate, which material under appropriate conditions self arranges to form 3D islands across the substrate surface. These islands are atomically flat at their top surface, and conform to the stepped surface of the substrate below at the island-substrate interface. Thereafter, the deposited materials are etched away, in the etch process the atomically flat surface areas of the islands transferred to the underlying substrate. Thereafter the substrate may be cleaned and annealed to remove any remaining unwanted contaminants, and eliminate any residual defects that may have remained in the substrate surface as a result of pre-existing imperfections of the substrate.

Influence of grafting solvents on the properties of polymer electrolyte membranes prepared by γ-ray preirradiation method

NASA Astrophysics Data System (ADS)

Kimura, Yosuke; Asano, Masaharu; Chen, Jinhua; Maekawa, Yasunari; Katakai, Ryoichi; Yoshida, Masaru

2008-07-01

The effect of grafting solvents, such as isopropanol (iPrOH), tetrachloroethane (TCE), tetrahydrofuran (THF), and toluene, on the preparation of poly(ethylene- co-tetrafluoroethylene)-graft-poly(styrene sulfonic acid) (ETFE-g-PSSA) electrolyte membranes by the γ-ray preirradiation grafting method was investigated. It was found that the iPrOH can drastically accelerate the grafting, resulting in a higher degree of grafting. However, for an appropriate degree of grafting of about 50%, the sulfonic acid groups in the ETFE-g-PSSA membrane prepared with the iPrOH were mainly distributed near the membrane surface, as shown by low proton conductivity in the membrane thickness direction. In contrast to this result, the ETFE-g-PSSA membranes prepared with the THF, toluene and TCE exhibited uniform distribution of the sulfonic acid groups in the membrane. Especially, in the case of the TCE grafting solvent, the chemical stability of the resultant electrolyte membrane was clearly higher than those prepared with the other grafting solvents.

Cobalt sulfide aerogel prepared by anion exchange method with enhanced pseudocapacitive and water oxidation performances.

PubMed

Gao, Qiuyue; Shi, Zhenyu; Xue, Kaiming; Ye, Ziran; Hong, Zhanglian; Yu, Xinyao; Zhi, Mingjia

2018-05-25

This work introduces the anion exchange method into the sol-gel process for the first time to prepare a metal sulfide aerogel. A porous Co 9 S 8 aerogel with a high surface area (274.2 m 2 g -1 ) and large pore volume (0.87 cm 3 g -1 ) has been successfully prepared by exchanging cobalt citrate wet gel in thioacetamide and subsequently drying in supercritical ethanol. Such a Co 9 S 8 aerogel shows enhanced supercapacitive performance and catalytic activity toward oxygen evolution reaction (OER) compared to its oxide aerogel counterpart. High specific capacitance (950 F g -1 at 1 A g -1 ), good rate capability (74.3% capacitance retention from 1 to 20 A g -1 ) and low onset overpotential for OER (220 mV) were observed. The results demonstrated here have implications in preparing various sulfide chalcogels.

Cobalt sulfide aerogel prepared by anion exchange method with enhanced pseudocapacitive and water oxidation performances

NASA Astrophysics Data System (ADS)

Gao, Qiuyue; Shi, Zhenyu; Xue, Kaiming; Ye, Ziran; Hong, Zhanglian; Yu, Xinyao; Zhi, Mingjia

2018-05-01

This work introduces the anion exchange method into the sol-gel process for the first time to prepare a metal sulfide aerogel. A porous Co9S8 aerogel with a high surface area (274.2 m2 g‑1) and large pore volume (0.87 cm3 g‑1) has been successfully prepared by exchanging cobalt citrate wet gel in thioacetamide and subsequently drying in supercritical ethanol. Such a Co9S8 aerogel shows enhanced supercapacitive performance and catalytic activity toward oxygen evolution reaction (OER) compared to its oxide aerogel counterpart. High specific capacitance (950 F g‑1 at 1 A g‑1), good rate capability (74.3% capacitance retention from 1 to 20 A g‑1) and low onset overpotential for OER (220 mV) were observed. The results demonstrated here have implications in preparing various sulfide chalcogels.

Printed Electronics

NASA Technical Reports Server (NTRS)

Lettow, John S. (Inventor); Crain, John M. (Inventor); Aksay, Ilhan A. (Inventor); Korkut, Sibel (Inventor); Chiang, Katherine S. (Inventor); Chen, Chuan-Hua (Inventor); Prud'Homme, Robert K. (Inventor)

2016-01-01

Printed electronic device comprising a substrate onto at least one surface of which has been applied a layer of an electrically conductive ink comprising functionalized graphene sheets and at least one binder. A method of preparing printed electronic devices is further disclosed.

Printed Electronics

NASA Technical Reports Server (NTRS)

Korkut, Sibel (Inventor); Chiang, Katherine S. (Inventor); Crain, John M. (Inventor); Aksay, Ilhan A. (Inventor); Lettow, John S. (Inventor); Chen, Chuan-Hua (Inventor); Prud'Homme, Robert K. (Inventor)

2018-01-01

Printed electronic device comprising a substrate onto at least one surface of which has been applied a layer of an electrically conductive ink comprising functionalized graphene sheets and at least one binder. A method of preparing printed electronic devices is further disclosed.

Printed Electronics

NASA Technical Reports Server (NTRS)

Aksay, Ilhan A. (Inventor); Chen, Chuan-Hua (Inventor); Lettow, John S. (Inventor); Chiang, Katherine S. (Inventor); Prud'Homme, Robert K. (Inventor); Crain, John M. (Inventor); Korkut, Sibel (Inventor)

2015-01-01

Printed electronic device comprising a substrate onto at least one surface of which has been applied a layer of an electrically conductive ink comprising functionalized graphene sheets and at least one binder. A method of preparing printed electronic devices is further disclosed.

Printed Electronics

NASA Technical Reports Server (NTRS)

Aksay, Ilhan A. (Inventor); Crain, John M. (Inventor); Chiang, Katherine S. (Inventor); Prud'Homme, Robert K. (Inventor); Lettow, John S. (Inventor); Korkut, Sibel A. (Inventor); Chen, Chuan-Hua (Inventor)

2014-01-01

Printed electronic device comprising a substrate onto at least one surface of which has been applied a layer of an electrically conductive ink comprising functionalized graphene sheets and at least one binder. A method of preparing printed electronic devices is further disclosed.

Printed electronics

NASA Technical Reports Server (NTRS)

Lettow, John S. (Inventor); Prud'Homme, Robert K. (Inventor); Crain, John M. (Inventor); Aksay, Ilhan A. (Inventor); Korkut, Sibel A. (Inventor); Chiang, Katherine S. (Inventor); Chen, Chuan-hua (Inventor)

2012-01-01

Printed electronic device comprising a substrate onto at least one surface of which has been applied a layer of an electrically conductive ink comprising functionalized graphene sheets and at least one binder. A method of preparing printed electronic devices is further disclosed.

A facile preparation route for netlike microstructures on a stainless steel using an ethanol-mediated femtosecond laser irradiation.

PubMed

Bian, Hao; Yang, Qing; Liu, Hewei; Chen, Feng; Du, Guangqing; Si, Jinhai; Hou, Xun

2013-03-01

Netlike or porous microstructures are highly desirable in metal implants and biomedical monitoring applications. However, realization of such microstructures remains technically challenging. Here, we report a facile and environmentally friendly method to prepare netlike microstructures on a stainless steel by taking the full advantage of the liquid-mediated femtosecond laser ablation. An unordered netlike structure and a quasi-ordered array of holes can be fabricated on the surface of stainless steel via an ethanol-mediated femtosecond laser line-scan method. SEM analysis of the surface morphology indicates that the porous netlike structure is in the micrometer scale and the diameter of the quasi-ordered holes ranges from 280 nm to 320 nm. Besides, we find that the obtained structures are tunable by altering the laser processing parameters especially scanning speed. Copyright © 2012 Elsevier B.V. All rights reserved.

Application of a mixed metal oxide catalyst to a metallic substrate

NASA Technical Reports Server (NTRS)

Sevener, Kathleen M. (Inventor); Lohner, Kevin A. (Inventor); Mays, Jeffrey A. (Inventor); Wisner, Daniel L. (Inventor)

2009-01-01

A method for applying a mixed metal oxide catalyst to a metallic substrate for the creation of a robust, high temperature catalyst system for use in decomposing propellants, particularly hydrogen peroxide propellants, for use in propulsion systems. The method begins by forming a prepared substrate material consisting of a metallic inner substrate and a bound layer of a noble metal intermediate. Alternatively, a bound ceramic coating, or frit, may be introduced between the metallic inner substrate and noble metal intermediate when the metallic substrate is oxidation resistant. A high-activity catalyst slurry is applied to the surface of the prepared substrate and dried to remove the organic solvent. The catalyst layer is then heat treated to bind the catalyst layer to the surface. The bound catalyst layer is then activated using an activation treatment and calcinations to form the high-activity catalyst system.

Room Temperature Gas Sensing Properties of Sn-Substituted Nickel Ferrite (NiFe2O4) Thin Film Sensors Prepared by Chemical Co-Precipitation Method

NASA Astrophysics Data System (ADS)

Manikandan, V.; Li, Xiaogan; Mane, R. S.; Chandrasekaran, J.

2018-04-01

Tin (Sn) substituted nickel ferrite (NiFe2O4) thin film sensors were prepared by a simple chemical co-precipitation method, which initially characterized their structure and surface morphology with the help of x-ray diffraction and scanning electron microscopy. Surface morphology of the sensing films reveals particles stick together with nearer particles and this formation leads to a large specific area as a large specific area is very useful for easy adsorption of gas molecules. Transmission electron microscopy and selected area electron diffraction pattern images confirm particle size and nanocrystallnity as due to formation of circular rings. Fourier transform infrared analysis has supported the presence of functional groups. The 3.69 eV optical band gap of the film was found which enabled better gas sensing. Gas sensors demonstrate better response and recovery characteristics, and the maximum response was 68.43%.

3D-Printed Bioactive Ca3SiO5 Bone Cement Scaffolds with Nano Surface Structure for Bone Regeneration.

PubMed

Yang, Chen; Wang, Xiaoya; Ma, Bing; Zhu, Haibo; Huan, Zhiguang; Ma, Nan; Wu, Chengtie; Chang, Jiang

2017-02-22

Silicate bioactive materials have been widely studied for bone regeneration because of their eminent physicochemical properties and outstanding osteogenic bioactivity, and different methods have been developed to prepare porous silicate bioactive ceramics scaffolds for bone-tissue engineering applications. Among all of these methods, the 3D-printing technique is obviously the most efficient way to control the porous structure. However, 3D-printed bioceramic porous scaffolds need high-temperature sintering, which will cause volume shrinkage and reduce the controllability of the pore structure accuracy. Unlike silicate bioceramic, bioactive silicate cements such as tricalcium silicate (Ca 3 SiO 5 and C 3 S) can be self-set in water to obtain high mechanical strength under mild conditions. Another advantage of using C 3 S to prepare 3D scaffolds is the possibility of simultaneous drug loading. Herein, we, for the first time, demonstrated successful preparation of uniform 3D-printed C 3 S bone cement scaffolds with controllable 3D structure at room temperature. The scaffolds were loaded with two model drugs and showed a loading location controllable drug-release profile. In addition, we developed a surface modification process to create controllable nanotopography on the surface of pore wall of the scaffolds, which showed activity to enhance rat bone-marrow stem cells (rBMSCs) attachment, spreading, and ALP activities. The in vivo experiments revealed that the 3D-printed C 3 S bone cement scaffolds with nanoneedle-structured surfaces significantly improved bone regeneration, as compared to pure C 3 S bone cement scaffolds, suggesting that 3D-printed C 3 S bone cement scaffolds with controllable nanotopography surface are bioactive implantable biomaterials for bone repair.

Surface polyPEGylation of Eu3+ doped luminescent hydroxyapatite nanorods through the combination of ligand exchange and metal free surface initiated atom transfer radical polymerization

NASA Astrophysics Data System (ADS)

Zeng, Guangjian; Liu, Meiying; Heng, Chunning; Huang, Qiang; Mao, Liucheng; Huang, Hongye; Hui, Junfeng; Deng, Fengjie; Zhang, Xiaoyong; Wei, Yen

2017-03-01

The Eu3+ doped luminescent hydroxyapatite (HAp) nanorods with uniform size and morphology can be synthesized by hydrothermal route. However, these HAp nanorods are coated by hydrophobic oleylamine, which makes them difficult to be dispersed in aqueous solution and impede their biomedical applications. In this work, Eu3+ doped luminescent polymers functionalized HAp nanorods were prepared through the combination of ligand exchange reaction and metal free surface initiated atom transfer radical polymerization (ATRP) method. In this procedure, the amino group functionalized HAp nanorods were first prepared by ligand exchange reaction using adenosine monophosphate (AMP) as ligand. Then the Br-containing initiators (HAp-Br) were introduced onto the surface of HAp-AMP nanorods through the amidation reaction. Finally, polymers functionalized HAp nanorods were prepared by metal free ATRP method using poly(ethylene glycol) methacrylate (PEGMA) as monomer and 10-phenylphenothiazine (PTH) as organic photocatalyst. The properties of these obtained HAp nanocomposites (HAP-polyPEGMA nanorods) were characterized by means of transmission electron microscopy, Fourier transformed infrared spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis in detail. The cell imaging of these HAP-polyPEGMA nanorods was examined using laser scanning confocal microscope to evaluate their biomedical applications. We demonstrated for the first time that hydrophobic luminescent HAp nanorods can be functionalized with polyPEGMA through the combination of ligand exchange reaction and metal free surface initiated ATRP. As compared with the traditional ATRP, the metal free ATRP can overcome the toxic and fluorescence quenching effects of metal catalysts such as copper ions. More importantly, the strategy described in this work should also be utilized for fabrications of many other luminescent polymer nanocomposites due to its good monomer adoptability.

Fluorescent proteins as efficient tools for evaluating the surface PEGylation of silica nanoparticles

NASA Astrophysics Data System (ADS)

Zhang, Wei; Ma, Minyan; Zhang, Xiao-ai; Zhang, Ze-yu; Saleh, Sayed M.; Wang, Xu-dong

2017-06-01

Surface PEGylation is essential for preventing non-specific binding of biomolecules when silica nanoparticles are utilized for in vivo applications. Methods for installing poly(ethylene glycol) on a silica surface have been widely explored but varies from study to study. Because there is a lack of a satisfactory method for evaluating the properties of silica surface after PEGylation, the prepared nanoparticles are not fully characterized before use. In some cases, even non-PEGylated silica nanoparticles were produced, which is unfortunately not recognized by the end-user. In this work, a fluorescent protein was employed, which acts as a sensitive material for evaluating the surface protein adsorption properties of silica nanoparticles. Eleven different methods were systematically investigated for their reaction efficiency towards surface PEGylation. Results showed that both reaction conditions (including pH, catalyst) and surface functional groups of parent silica nanoparticles play critical roles in producing fully PEGylated silica nanoparticles. Great care needs to be taken in choosing the proper coupling chemistry for surface PEGylation. The data and method shown here will guarantee high-quality PEGylated silica nanoparticles to be produced and guide their applications in biology, chemistry, industry and medicine.

A fundamental approach to adhesion: Synthesis, surface analysis, thermodynamics and mechanics. [titanium alloys

NASA Technical Reports Server (NTRS)

Chen, W.; Dwight, D. W.; Wightman, J. P.

1978-01-01

Various surface preparations for titanium 6-4 alloy were studied. An anodizing method was investigated, and compared with the results of other chemical treatments, namely, phosphate/fluoride, Pasa-Jell and Turco. The relative durability of the different surface treatments was assessed by monitoring changes in surface chemistry and morphology occasioned by aging at 505 K (450 F). Basic electron spectroscopic data were collected for polyimide and polyphenylquinoxaline adhesives and synthetic precursors. Fractographic studies were completed for several combinations of adherend, adhesive, and testing conditions.

Evaluation of transport parameters for PVC based polyvinyl alcohol Ce(IV) phosphate composite membrane.

PubMed

Khan, Mohammad Mujahid Ali; Rafiuddin; Inamuddin

2013-05-01

The aim of this study was to investigate the preparation of novel membrane and the characterization of their properties. A new class of polyvinyl chloride (PVC) based polyvinyl alcohol Ce(IV) phosphate composite membrane was successfully prepared by solution casting method. The structural formation was confirmed by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and morphological studies. The thermal property was investigated by thermogravimetry analysis (TGA) method. The order of surface charge density for various electrolytes was found to be LiCl

Immobilized lipid-bilayer materials

DOEpatents

Sasaki, Darryl Y.; Loy, Douglas A.; Yamanaka, Stacey A.

2000-01-01

A method for preparing encapsulated lipid-bilayer materials in a silica matrix comprising preparing a silica sol, mixing a lipid-bilayer material in the silica sol and allowing the mixture to gel to form the encapsulated lipid-bilayer material. The mild processing conditions allow quantitative entrapment of pre-formed lipid-bilayer materials without modification to the material's spectral characteristics. The method allows for the immobilization of lipid membranes to surfaces. The encapsulated lipid-bilayer materials perform as sensitive optical sensors for the detection of analytes such as heavy metal ions and can be used as drug delivery systems and as separation devices.

Internal zone growth method for producing metal oxide metal eutectic composites

DOEpatents

Clark, Grady W.; Holder, John D.; Pasto, Arvid E.

1980-01-01

An improved method for preparing a cermet comprises preparing a compact having about 85 to 95 percent theoretical density from a mixture of metal and metal oxide powders from a system containing a eutectic composition, and inductively heating the compact in a radiofrequency field to cause the formation of an internal molten zone. The metal oxide particles in the powder mixture are effectively sized relative to the metal particles to permit direct inductive heating of the compact by radiofrequency from room temperature. Surface melting is prevented by external cooling or by effectively sizing the particles in the powder mixture.

A simple method for the preparation of activated carbon fibers coated with graphite nanofibers.

PubMed

Kim, Byung-Joo; Park, Soo-Jin

2007-11-15

A simple method is described for the preparation of activated carbon fibers (ACFs) coated with graphite nanofibers (GNFs). Low-pressure-plasma mixed-gas (Ar/O2) treatment of the ACFs led to the growth of GNFs on their surface. The growth was greater at higher power inputs, and from TEM observations the GNFs were seen to be of herringbone type. It was found that the N2 adsorption capacity of the ACFs did not sharply decrease, and that volume resistivity of the ACFs enhanced as a result of this treatment.

Supersonic Retropulsion Surface Preparation of Carbon Fiber Reinforced Epoxy Composites for Adhesive Bonding

NASA Technical Reports Server (NTRS)

Palmieri, Frank L.; Belcher, Marcus A.; Wohl, Christopher J.; Blohowiak, Kay Y.; Connell, John W.

2013-01-01

Surface preparation is widely recognized as a key step to producing robust and predictable bonds in a precise and reproducible manner. Standard surface preparation techniques, including grit blasting, manual abrasion, and peel ply, can lack precision and reproducibility, which can lead to variation in surface properties and subsequent bonding performance. The use of a laser to ablate composite surface resin can provide an efficient, precise, and reproducible means of preparing composite surfaces for adhesive bonding. Advantages include elimination of physical waste (i.e., grit media and sacrificial peel ply layers that ultimately require disposal), reduction in process variability due to increased precision (e.g. increased reproducibility), and automation of surface preparation, all of which improve reliability and process control. This paper describes a Nd:YAG laser surface preparation technique for composite substrates and the mechanical performance and failure modes of bonded laminates thus prepared. Additionally, bonded specimens were aged in a hot, wet environment for approximately one year and subsequently mechanically tested. The results of a one year hygrothermal aging study will be presented.

Preparation of extrusions of bulk mixed oxide compounds with high macroporosity and mechanical strength

DOEpatents

Flytzani-Stephanopoulos, Maria; Jothimurugesan, Kandaswami

1990-01-01

A simple and effective method for producing bulk single and mixed oxide absorbents and catalysts is disclosed. The method yields bulk single oxide and mixed oxide absorbent and catalyst materials which combine a high macroporosity with relatively high surface area and good mechanical strength. The materials are prepared in a pellet form using as starting compounds, calcined powders of the desired composition and physical properties these powders are crushed to broad particle size distribution, and, optionally may be combined with an inorganic clay binder. The necessary amount of water is added to form a paste which is extruded, dried and heat treated to yield and desired extrudate strength. The physical properties of the extruded materials (density, macroporosity and surface area) are substantially the same as the constituent powder is the temperature of the heat treatment of the extrudates is approximately the same as the calcination temperature of the powder. If the former is substantially higher than the latter, the surface area decreases, but the macroporosity of the extrusions remains essentially constant.

Liquid Phase Plasma Synthesis of Iron Oxide Nanoparticles on Nitrogen-Doped Activated Carbon Resulting in Nanocomposite for Supercapacitor Applications.

PubMed

Lee, Heon; Lee, Won-June; Park, Young-Kwon; Ki, Seo Jin; Kim, Byung-Joo; Jung, Sang-Chul

2018-03-25

Iron oxide nanoparticles supported on nitrogen-doped activated carbon powder were synthesized using an innovative plasma-in-liquid method, called the liquid phase plasma (LPP) method. Nitrogen-doped carbon (NC) was prepared by a primary LPP reaction using an ammonium chloride reactant solution, and an iron oxide/NC composite (IONCC) was prepared by a secondary LPP reaction using an iron chloride reactant solution. The nitrogen component at 3.77 at. % formed uniformly over the activated carbon (AC) surface after a 1 h LPP reaction. Iron oxide nanoparticles, 40~100 nm in size, were impregnated homogeneously over the NC surface after the LPP reaction, and were identified as Fe₃O₄ by X-ray photoelectron spectroscopy and X-ray diffraction. NC and IONCCs exhibited pseudo-capacitive characteristics, and their specific capacitance and cycling stability were superior to those of bare AC. The nitrogen content on the NC surface increased the compatibility and charge transfer rate, and the composites containing iron oxide exhibited a lower equivalent series resistance.

Fabrication and surface enhanced Raman scattering effect of centimeter level AgCuAu composite nanowires

NASA Astrophysics Data System (ADS)

Xu, Dapeng; Zhang, Song; Yang, Wei; Chen, Jian

2017-10-01

Centimeter level AgCuAu composite nanowires were prepared by a solid-state ionics method under a direct current electric field (DCEF) using fast ionic conductor RbAg4I5 films and vacuum thermal evaporation method. The surface morphology and chemical composition of the AuAgCu composite nanowires were characterized by scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), respectively. Raman enhancement performance of the AgCuAu composite nanowires substrates was detected by Rhodamine 6G (R6G) aqueous solutions as probe molecules. Long-range order and short-range order AgCuAu composite nanowires with the length of 1 cm were prepared. The nanowires were bamboo-shaped with high surface roughness and the diameters of nanowires ranged from 60 to 100 nm. The molar ratio of Ag:Cu:Au in composite nanowires is 15:2:1. The intrinsic Raman peaks of 10-16 mol/L R6G at 612, 773, 1125, 1182, 1307, 1361, 1418, 1506, 1545, 1575, 1597, 1650 cm-1 are all present when AgCuAu composite nanowires were used as the SERS substrates.

Chemical and electrical passivation of Si(1 1 1) surfaces

NASA Astrophysics Data System (ADS)

Tian, Fangyuan; Yang, Dan; Opila, Robert L.; Teplyakov, Andrew V.

2012-01-01

This paper compares the physical and chemical properties of hydrogen-passivated Si(1 1 1) single crystalline surfaces prepared by two main chemical preparation procedures. The modified RCA cleaning is commonly used to prepare atomically flat stable surfaces that are easily identifiable spectroscopically and are the standard for chemical functionalization of silicon. On the other hand electronic properties of these surfaces are sometimes difficult to control. A much simpler silicon surface preparation procedure includes HF dipping for a short period of time. This procedure yields an atomically rough surface, whose chemical identity is not well-defined. However, the surfaces prepared by this approach often exhibit exceptionally attractive electronic properties as determined by long charge carrier lifetimes. This work utilizes infrared spectroscopy and X-ray photoelectron spectroscopy to investigate chemical modification of the surfaces prepared by these two different procedures with PCl5 (leading to surface chlorination) and with short- and long-alkyl-chain alkenes (1-decene and 1-octodecene, respectively) and follows the electronic properties of the starting surfaces produced by measuring charge-carrier lifetimes.

Preparation of bioactive titania films on titanium metal via anodic oxidation.

PubMed

Cui, X; Kim, H-M; Kawashita, M; Wang, L; Xiong, T; Kokubo, T; Nakamura, T

2009-01-01

To research the crystal structure and surface morphology of anodic films on titanium metal in different electrolytes under various electrochemical conditions and investigate the effect of the crystal structure of the oxide films on apatite-forming ability in simulated body fluid (SBF). Titanium oxide films were prepared using an anodic oxidation method on the surface of titanium metal in four different electrolytes: sulfuric acid, acetic acid, phosphoric acid and sodium sulfate solutions with different voltages for 1 min at room temperature. Anodic films that consisted of rutile and/or anatase phases with porous structures were formed on titanium metal after anodizing in H(2)SO(4) and Na(2)SO(4) electrolytes, while amorphous titania films were produced after anodizing in CH(3)COOH and H(3)PO(4) electrolytes. Titanium metal with the anatase and/or rutile crystal structure films showed excellent apatite-forming ability and produced a compact apatite layer covering all the surface of titanium after soaking in SBF for 7d, but titanium metal with amorphous titania layers was not able to induce apatite formation. The resultant apatite layer formed on titanium metal in SBF could enhance the bonding strength between living tissue and the implant. Anodic oxidation is believed to be an effective method for preparing bioactive titanium metal as an artificial bone substitute even under load-bearing conditions.

Mass Spectrometry as a Preparative Tool for the Surface Science of Large Molecules

NASA Astrophysics Data System (ADS)

Rauschenbach, Stephan; Ternes, Markus; Harnau, Ludger; Kern, Klaus

2016-06-01

Measuring and understanding the complexity that arises when nanostructures interact with their environment are one of the major current challenges of nanoscale science and technology. High-resolution microscopy methods such as scanning probe microscopy have the capacity to investigate nanoscale systems with ultimate precision, for which, however, atomic scale precise preparation methods of surface science are a necessity. Preparative mass spectrometry (pMS), defined as the controlled deposition of m/z filtered ion beams, with soft ionization sources links the world of large, biological molecules and surface science, enabling atomic scale chemical control of molecular deposition in ultrahigh vacuum (UHV). Here we explore the application of high-resolution scanning probe microscopy and spectroscopy to the characterization of structure and properties of large molecules. We introduce the fundamental principles of the combined experiments electrospray ion beam deposition and scanning tunneling microscopy. Examples for the deposition and investigation of single particles, for layer and film growth, and for the investigation of electronic properties of individual nonvolatile molecules show that state-of-the-art pMS technology provides a platform analog to thermal evaporation in conventional molecular beam epitaxy. Additionally, it offers additional, unique features due to the use of charged polyatomic particles. This new field is an enormous sandbox for novel molecular materials research and demands the development of advanced molecular ion beam technology.

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

Self-Cleaning Surfaces Prepared By Microstructuring System

NASA Astrophysics Data System (ADS)

Sabbah, Abbas; Vandeparre, H.; Brau, F.; Damman, P.

The wettability of materials is a very important aspect of surface science governed by the chemical composition of the surface and its morphology. In this context, materials replicating nature's superhydrophobic surfaces, such as lotus leafs, rose petals and butterfly wings, have widely attracted attention of physicists and material engineers [1-3]. Despite of considerable efforts during the last decade, superhydrophobic surfaces are still expensive and usually involved microfabrication processes, such as photolithography technique. In this study, we propose an original and simple method to create superhydrophobic surfaces by controling elastic instabilities [4-8]. Indeed, we demonstrate that the self-organization of wrinkles on top of non-wettable polymer surfaces leads to surperhydrophobic surfaces.

Method of preparing a negative electrode including lithium alloy for use within a secondary electrochemical cell

DOEpatents

Tomczuk, Z.; Olszanski, W.; Battles, J.E.

1975-12-09

A negative electrode that includes a lithium alloy as active material is prepared by briefly submerging a porous, electrically conductive substrate within a melt of the alloy. Prior to solidification, excess melt can be removed by vibrating or otherwise manipulating the filled substrate to expose interstitial surfaces. Electrodes of such a solid lithium--aluminum filled within a substrate of metal foam are provided. 1 figure, 1 table.

Organic inorganic hybrid coating (poly(methyl methacrylate)/monodisperse silica)

NASA Astrophysics Data System (ADS)

Rubio, E.; Almaral, J.; Ramírez-Bon, R.; Castaño, V.; Rodríguez, V.

2005-04-01

Polymethylmethacrylate-silica hybrid coatings were prepared from methyl methacrylate and monodisperse colloidal silica prepared by the Stöber method. The surfaces of the spheres were successfully modified by chemical reaction with 3-(trimethoxysilyl) propyl methacrylate (TMSPM) to compatibilise the organic and inorganic components of the precursor solution mixture. The coatings were deposited by dip-coating on glass substrates. They result with good properties of homogeneity, optical transparence, hardness and adhesion.

Graphene oxide for solid-phase extraction of bioactive phenolic acids.

PubMed

Hou, Xiudan; Wang, Xusheng; Sun, Yingxin; Wang, Licheng; Guo, Yong

2017-05-01

A solid-phase extraction (SPE) method for the efficient analysis of trace phenolic acids (PAs, caffeic acid, ferulic acid, protocatechuic acid, cinnamic acid) in urine was established. In this work, a graphene oxide (GO) coating was grafted onto pure silica to be investigated as SPE material. The prepared GO surface had a layered and wrinkled structure that was rough and well organized, which could provide more open adsorption sites. Owing to its hydrophilicity and polarity, GO showed higher extraction efficiency toward PAs than reduced GO did, in agreement with the theoretical calculation results performed by Gaussian 09 software. The adsorption mechanism of PAs on GO@Sil was also investigated through static state and kinetic state adsorption experiments, which showed a monolayer surface adsorption. Extraction capacity of the as-prepared material was optimized using the response surface methodology. Under the optimized conditions, the as-established method provided wide linearity range (2-50 μg L -1 for protocatechuic acid and 1-50 μg L -1 for caffeic acid, ferulic acid, and cinnamic acid) and low limits of detection (0.25-1 μg L -1 ). Finally, the established method was applied for the analysis of urine from two healthy volunteers. The results indicate that the prepared material is a practical, cost-effective medium for the extraction and determination of phenolic acids in complex matrices. Graphical Abstract A graphene oxide coating was grafted onto pure silica as the SPE material for the extraction of phenolic acids in urines and the extraction mechanism was also mainly investigated.

Influence of calcinated and non calcinated nanobioglass particles on hardness and bioactivity of sol-gel-derived TiO2-SiO2 nano composite coatings on stainless steel substrates.

PubMed

Dadash, Mohammad Saleh; Karbasi, Saeed; Esfahani, Mojtaba Nasr; Ebrahimi, Mohammad Reza; Vali, Hojatollah

2011-04-01

Thick films of calcinated and non calcinated nanobioglass (NBG)-titania composite coatings were prepared on stainless steel substrates by alkoxide sol-gel process. Dip-coating method was used for the films preparation. The morphology, structure and composition of the nano composite films were evaluated using environmental scanning electron microscope, X-ray diffraction and Fourier transform infrared spectroscope. The SEM investigation results showed that prepared thick NBG-titania films are smooth and free of macrocracking, fracture or flaking. The grain size of these films was uniform and nano scale (50-60 nm) which confirmed with TEM. Also FTIR confirmed the presence of Si-O-Si bands on the calcinated NBG-titania films. The hardness of the prepared films (TiO(2)-calcinated NBG and TiO(2)-Non calcinated NBG) was compared by using micro hardness test method. The results verified that the presence of calcinated NBG particles in NBG-titania composite enhanced gradually the mechanical data of the prepared films. The in vitro bioactivity of these films was discussed based on the analysis of the variations of Ca and P concentrations in the simulated body fluid (SBF) and their surface morphologies against immersion time. Surface morphology and Si-O-Si bands were found to be of great importance with respect to the bioactivity of the studied films. The results showed that calcinated NBG-titania films have better bioactivity than non calcinated NBG-titania films.

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

Ma, Hongwei; Shen, Jianfeng; Shi, Min

Graphical abstract: . The as-obtained ({alpha}-MnO{sub 2}) nanomaterials could act as an adsorbent to remove Conge red. More significantly, the nanomaterials are nontoxic and environmentally friendly though a biological MTT assay experiment. Plots of the capacity to remove Conge red with time by the commercial and new-prepared {alpha}-MnO{sub 2}. Inset shows absorption of Congo Red with time by new-prepared rod-clusters {alpha}-MnO{sub 2} (0, 10, 20, 40 and 60 min, respectively). Highlights: {yields} Nanostructured {alpha}-MnO{sub 2} was prepared through a template-free hydrothermal method. {yields} The obtained {alpha}-MnO{sub 2} could act as effective adsorbents to remove organic dyes. {yields} The obtained adsorbentsmore » are environmentally friendly. -- Abstract: In this paper, nanostructured MnO{sub 2} materials were successfully prepared through a simple and template-free hydrothermal method. X-ray diffraction pattern indicates that the as-prepared nanomaterials are {alpha}-MnO{sub 2}. Transmission Electron Microscopy and Scanning Electron Microscopy images demonstrate that nanostructured rod-clusters {alpha}-MnO{sub 2} could be evolved from the nanorods. Brunauer-Emmett-Teller (BET) surface area measurement was employed to characterize the surface property. Moreover, the as-obtained ({alpha}-MnO{sub 2}) nanomaterials could act as an efficient adsorbent to remove Congo Red and Methlylene Blue. More significantly, the nanomaterials are nontoxic and environmentally friendly via biological methylthiazolyldiphenyltetrazoliumbromide assay experiments. Its nontoxic and enhanced adsorbability properties guarantee their safe applications in environmental protection and industrial aspects.« less

Electrically conducting polyimide film containing tin complexes

NASA Technical Reports Server (NTRS)

St.clair, Anne K. (Inventor); Ezzell, Stephen A. (Inventor)

1994-01-01

Disclosed is a thermally-stable SnO2-surfaced polyimide film wherein the electrical conductivity of the SnO2 surface is within the range of about 3.0 x 10(exp -3) to about 1 x 10(exp -2) ohms(exp -1). Also disclosed is a method of preparing this film from a solution containing a polyamic acid and SnCl4 (DMSO)2.

Elucidation of the surface characteristics and electrochemistry of high-performance LiNiO 2

DOE PAGES

Xu, Jing; Lin, Feng; Nordlund, Dennis; ...

2016-02-25

Phase pure LiNiO 2 was prepared using a solid-state method and the optimal synthesis conditions led to a remarkably high capacity of 200 mA h g $-$1 with excellent retention. The combination of bulk and surface characterization elucidated an essential role of the excess Li in phase formation during synthesis and the subsequent electrochemical performance.

Development of a Low-Alcohol Drink Similar in Sensory Properties to a Full-Alcohol Drink

ERIC Educational Resources Information Center

Ross, Carolyn F.; Weller, Karen

2008-01-01

The objective of this study was to examine different methods of preparation of a low-alcohol drink for use as a control in behavioral studies. Treatments included: untreated juice, juice with alcohol (rum), juice with rum floated on the surface and juice with ethanol floated on the surface. Untrained panelists (n=48) rated each drink for overall…

Formation of conductive polymers using nitrosyl ion as an oxidizing agent

DOEpatents

Choi, Kyoung-Shin; Jung, Yongju; Singh, Nikhilendra

2016-06-07

A method of forming a conductive polymer deposit on a substrate is disclosed. The method may include the steps of preparing a composition comprising monomers of the conductive polymer and a nitrosyl precursor, contacting the substrate with the composition so as to allow formation of nitrosyl ion on the exterior surface of the substrate, and allowing the monomer to polymerize into the conductive polymer, wherein the polymerization is initiated by the nitrosyl ion and the conductive polymer is deposited on the exterior surface of the substrate. The conductive polymer may be polypyrrole.

Laser desorption ionization and peptide sequencing on laser induced silicon microcolumn arrays

DOEpatents

Vertes, Akos [Reston, VA; Chen, Yong [San Diego, CA

2011-12-27

The present invention provides a method of producing a laser-patterned silicon surface, especially silicon wafers for use in laser desorption ionization (LDI-MS) (including MALDI-MS and SELDI-MS), devices containing the same, and methods of testing samples employing the same. The surface is prepared by subjecting a silicon substrate to multiple laser shots from a high-power picosecond or femtosecond laser while in a processing environment, e.g., underwater, and generates a remarkable homogenous microcolumn array capable of providing an improved substrate for LDI-MS.

Clear microstructure-performance relationships in Mn-containing perovskite and hexaaluminate compounds prepared by activated reactive synthesis.

PubMed

Laassiri, Said; Bion, Nicolas; Duprez, Daniel; Royer, Sébastien; Alamdari, Houshang

2014-03-07

Microstructural properties of mixed oxides play essential roles in their oxygen mobility and consequently in their catalytic performances. Two families of mixed oxides (perovskite and hexaaluminate) with different microstructural features, such as crystal size and specific surface area, were prepared using the activated reactive synthesis (ARS) method. It was shown that ARS is a flexible route to synthesize both mixed oxides with nano-scale crystal size and high specific surface area. Redox properties and oxygen mobility were found to be strongly affected by the material microstructure. Catalytic activities of hexaaluminate and perovskite materials for methane oxidation were discussed in the light of structural, redox and oxygen mobility properties.

Multifunctional transparent ZnO nanorod films.

PubMed

Kwak, Geunjae; Jung, Sungmook; Yong, Kijung

2011-03-18

Transparent ZnO nanorod (NR) films that exhibit extreme wetting states (either superhydrophilicity or superhydrophobicity through surface chemical modification), high transmittance, UV protection and antireflection have been prepared via the facile ammonia hydrothermal method. The periodic 1D ZnO NR arrays showed extreme wetting states as well as antireflection properties due to their unique surface structure and prevented the UVA region from penetrating the substrate due to the unique material property of ZnO. Because of the simple, time-efficient and low temperature preparation process, ZnO NR films with useful functionalities are promising for fabrication of highly light transmissive, antireflective, UV protective, antifogging and self-cleaning optical materials to be used for optical devices and photovoltaic energy devices.

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.

About complex refractive index of black Si

NASA Astrophysics Data System (ADS)

Pinčík, Emil; Brunner, Robert; Kobayashi, Hikaru; Mikula, Milan

2017-12-01

The paper deals with the complex refractive index in the IR light region of two types of samples (i) as prepared black silicon, and (ii) thermally oxidized black silicon (BSi) nano-crystalline specimens produced both by the surface structure chemical transfer method using catalytic Ag evaporated spots (as prepared sample) and by the catalytic Pt catalytic mesh (thermally oxidized sample). We present, compare, and discuss the values of the IR complex refractive index obtained by calculation using the Kramers-Krönig transformation. Results indicate that small differences between optical properties of as prepared black Si and thermally oxidized BSi are given by: (i) - oxidation procedure, (ii) - thickness of the formed black Si layer, mainly, not by utilization of different catalytic metals, and by iii) the different thickness. Contamination of the surface by different catalytic metals contributes almost equally to the calculated values of the corresponding complex refractive index.

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.

Study on room temperature gas-sensing performance of CuO film-decorated ordered porous ZnO composite by In2O3 sensitization

NASA Astrophysics Data System (ADS)

Li, Tian-tian; Bao, Na; Geng, Ai-fang; Yu, Hui; Yang, Ying; Dong, Xiang-ting

2018-02-01

For the first time, ordered mesoporous ZnO nanoparticles have been synthesized by a template method. The electroplating after chemical plating method was creatively used to form copper film on the surface of the prepared ZnO, and then a CuO film-decorated ordered porous ZnO composite (CuO/ZnO) was obtained by a high-temperature oxidation method. In2O3 was loaded into the prepared CuO film-ZnO by an ultrasonic-assisted method to sensitize the room temperature gas-sensing performance of the prepared CuO/ZnO materials. The doped In2O3 could effectively improve the gas-sensing properties of the prepared materials to nitrogen oxides (NOx) at room temperature. The 1% In2O3 doped CuO/ZnO sample (1 wt% In2O3-CuO/ZnO) showed the best gas-sensing properties whose response to 100 ppm NOx reached 82%, and the detectable minimum concentration reached 1 ppm at room temperature. The prepared materials had a good selectivity, better response, very low detection limit, and high sensitivity to NOx gas at room temperature, which would have a great development space in the gas sensor field and a great research value.

Atomic Layer-Deposited TiO2 Coatings on NiTi Surface

NASA Astrophysics Data System (ADS)

Vokoun, D.; Racek, J.; Kadeřávek, L.; Kei, C. C.; Yu, Y. S.; Klimša, L.; Šittner, P.

2018-02-01

NiTi shape-memory alloys may release poisonous Ni ions at the alloys' surface. In an attempt to prepare a well-performing surface layer on an NiTi sample, the thermally grown TiO2 layer, which formed during the heat treatment of NiTi, was removed and replaced with a new TiO2 layer prepared using the atomic layer deposition (ALD) method. Using x-ray photoelectron spectroscopy, it was found that the ALD layer prepared at as low a temperature as 100 °C contained Ti in oxidation states + 4 and + 3. As for static corrosion properties of the ALD-coated NiTi samples, they further improved compared to those covered by thermally grown oxide. The corrosion rate of samples with thermally grown oxide was 1.05 × 10-5 mm/year, whereas the corrosion rate of the ALD-coated samples turned out to be about five times lower. However, cracking of the ALD coating occurred at about 1.5% strain during the superelastic mechanical loading in tension taking place via the propagation of a localized martensite band.

THERMAL DECOMPOSITION OF URANIUM COMPOUNDS

DOEpatents

Magel, T.T.; Brewer, L.

1959-02-10

A method is presented of preparing uranium metal of high purity consisting contacting impure U metal with halogen vapor at between 450 and 550 C to form uranium halide vapor, contacting the uranium halide vapor in the presence of H/sub 2/ with a refractory surface at about 1400 C to thermally decompose the uranium halides and deposit molten U on the refractory surface and collecting the molten U dripping from the surface. The entire operation is carried on at a sub-atmospheric pressure of below 1 mm mercury.

Composition-dependent surface chemistry of colloidal Ba xSr 1-xTiO 3 perovskite nanocrystals

DOE PAGES

Margossian, Tigran; Culver, Sean P.; Larmier, Kim; ...

2016-11-01

Ba xSr 1-xTiO 3 perovskite nanocrystals, prepared by the vapor diffusion sol-gel method and characterized by state of the art surface techniques, display significantly different O-H stretching frequencies and adsorption properties towards CO 2 as a function of the alkaline earth composition (Ba vs. Sr). Lastly, the difference of properties can be associated with the more basic nature of BaO-rich than SrO-rich surfaces.

Preparation of fine-particles at cryogenic temperatures

NASA Technical Reports Server (NTRS)

Globus, H.

1970-01-01

Flash freezing process yields gelling agent for use at cryogenic temperatures. Vaporized material, diluted with an inert gas, is injected below the surface of an agitated cryogenic liquid. This method disperses particles of chlorine trifluoride in liquid oxygen difluoride.

Preparation and visible-light photocatalytic properties of BiNbO₄ and BiTaO₄ by a citrate method

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

Zhai, Hai-Fa, E-mail: haifazhai@126.com; Li, Ai-Dong, E-mail: adli@nju.edu.cn; Kong, Ji-Zhou

2013-06-01

Visible-light photcatalysts of BiNbO₄ and BiTaO₄ powders have been successfully synthesized by a citrate method. The formation of pure triclinic phase of BiNbO₄ and BiTaO₄ at low temperature of 700 °C can be attributed to the advantage of the citrate method. The photocatalytic activity and possible mechanism were investigated deeply. For BiNbO₄ particles, the mechanism of methyl violet (MV) degradation under visible light irradiation involves photocatalytic and photosensitization pathways and the catalyst specific surface area has dominant influence. While for BiTaO₄ particles, the dominant mechanism arises from photosensitization pathways and a trade off between high specific surface area and goodmore » crystallinity is achieved. BiNbO₄ powder calcined at 700 °C shows the best photocatalytic efficiency among these catalysts, which is ascribed to its large surface area and more positive conduction band level. The optimal catalyst loading, additive H₂O₂ concentration and pH value is around 1 g/L, 2 mmol/L and 8 mmol/L, respectively. - Graphical abstract: Photodegradation performance and adsorption ability of BiNbO₄ and BiTaO₄ powders, respectively. BNO700 with the best photocatalytic efficiency is ascribed to its large surface area and more positive conduction band level. Highlights: • Pure BiNbO₄ and BiTaO₄ powders were prepared by a citrate method. • Excellent performance of visible-light degradation of MV was observed. • Different MV degradation mechanism for BiNbO₄ and BiTaO₄ powders was proposed. • BNO700 has large surface area and more positive conduction band level.« less

Thermal Conductivity of a Nanoscale Yttrium Iron Garnet Thin-Film Prepared by the Sol-Gel Process

PubMed Central

2017-01-01

The thermal conductivity of a nanoscale yttrium iron garnet (Y3Fe5O12, YIG) thin-film prepared by a sol-gel method was evaluated using the ultrafast pump-probe technique in the present study. The thermoreflectance change on the surface of a 250 nm thick YIG film, induced by the irradiation of femtosecond laser pulses, was measured, and curve fitting of a numerical solution for the transient heat conduction equation to the experimental data was performed using the finite difference method in order to extract the thermal property. Results show that the film’s thermal conductivity is 22–83% higher than the properties of bulk YIG materials prepared by different fabrication techniques, reflecting the microstructural characteristics and quality of the film. PMID:28858249

Facile method for preparing superoleophobic surfaces with hierarchical microcubic/nanowire structures

NASA Astrophysics Data System (ADS)

Kwak, Wonshik; Hwang, Woonbong

2016-02-01

To facilitate the fabrication of superoleophobic surfaces having hierarchical microcubic/nanowire structures (HMNS), even for low surface tension liquids including octane (surface tension = 21.1 mN m-1), and to understand the influences of surface structures on the oleophobicity, we developed a convenient method to achieve superoleophobic surfaces on aluminum substrates using chemical acid etching, anodization and fluorination treatment. The liquid repellency of the structured surface was validated through observable experimental results the contact and sliding angle measurements. The etching condition required to ensure high surface roughness was established, and an optimal anodizing condition was determined, as a critical parameter in building the superoleophobicity. The microcubic structures formed by acid etching are essential for achieving the formation of the hierarchical structure, and therefore, the nanowire structures formed by anodization lead to an enhancement of the superoleophobicity for low surface tension liquids. Under optimized morphology by microcubic/nanowire structures with fluorination treatment, the contact angle over 150° and the sliding angle less than 10° are achieved even for octane.

A novel organic solvent-based coupling method for the preparation of covalently immobilized proteins on gold.

PubMed Central

Parker, M. C.; Patel, N.; Davies, M. C.; Roberts, C. J.; Tendler, S. J.; Williams, P. M.

1996-01-01

A novel organic solvent-based coupling method has been developed for the covalent immobilization of biological material to gold surfaces. The method employs the polar organic solvent anhydrous 2,2,2-trifluoroethanol as the reaction medium and involves dissolution of the protein (catalase) in the solvent allowing protein coupling to proceed under basic conditions in a dry organic environment. The advantage of this method is that protein attachment is favored over hydrolysis of the coupling reagent. We have shown qualitatively and quantitatively that following attachment to the gold surface a significant proportion of the enzyme catalase remains catalytically active (at least 20-31%). PMID:8931151

Towards the preparation of realistic model Ziegler-Natta catalysts: XPS study of the MgCl 2/TiCl 4 interaction with flat SiO 2/Si(1 0 0)

NASA Astrophysics Data System (ADS)

Siokou, Angeliki; Ntais, Spyridon

2003-08-01

Despite of the wide use of supported Ti based Ziegler-Natta catalysts in the olefin polymerization industry, questions concerning the role of each one of the catalyst components in the polymerization process, have not found a satisfactory answer yet. This is mainly because of the high sensitivity of these systems to oxygen and atmospheric moisture that makes their study in an atomic level rather complicated. Realistic surface science models of the pre-activated SiO 2 supported MgCl 2/TiCl 4 and TiCl 4 Ziegler-Natta catalysts were prepared by spin coating on flat conductive SiO 2/Si(1 0 0) supports under inert atmosphere. This preparation technique resembles the wet chemical impregnation which is the industrial method of the catalyst preparation. XPS analysis showed that the catalyst precursor anchors on the silica surface through bonding of the Ti atoms with surface silanes or siloxanes, while Mg is attached to the Ti through chlorine bridges. Thermal treatment of the catalysts at 723 K leads to total Cl desorption when MgCl 2 is not present while a significant amount of the Ti atoms is reduced to the Ti 3+ state.

Preparation of hydrophobic coatings

DOEpatents

Branson, Eric D [Albuquerque, NM; Shah, Pratik B [Albuquerque, NM; Singh, Seema [Rio Rancho, NM; Brinker, C Jeffrey [Albuquerque, NM

2009-02-03

A method for preparing a hydrophobic coating by preparing a precursor sol comprising a metal alkoxide, a solvent, a basic catalyst, a fluoroalkyl compound and water, depositing the precursor sol as a film onto a surface, such as a substrate or a pipe, heating, the film and exposing the film to a hydrophobic silane compound to form a hydrophobic coating with a contact angle greater than approximately 150.degree.. The contact angle of the film can be controlled by exposure to ultraviolet radiation to reduce the contact angle and subsequent exposure to a hydrophobic silane compound to increase the contact angle.

TiOx-based thin-film transistors prepared by femtosecond laser pre-annealing

NASA Astrophysics Data System (ADS)

Shan, Fei; Kim, Sung-Jin

2018-02-01

We report on thin-film transistors (TFTs) based on titanium oxide (TiOx) prepared using femtosecond laser pre-annealing for electrical application of n-type channel oxide transparent TFTs. Amorphous TFTs using TiOx semiconductors as an active layer have a low-temperature process and show remarkable electrical performance. And the femtosecond laser pre-annealing process has greater flexibility and development space for semiconductor production activity, with a fast preparation method. TFTs with a TiOx semiconductor pre-annealed via femtosecond laser at 3 W have a pinhole-free and smooth surface without crystal grains.

Porcelain surface alterations and refinishing after use of two orthodontic bonding methods.

PubMed

Herion, Drew T; Ferracane, Jack L; Covell, David A

2010-01-01

To compare porcelain surfaces at debonding after use of two surface preparation methods and to evaluate a method for restoring the surface. Lava Ceram feldspathic porcelain discs (n = 40) underwent one of two surface treatments prior to bonding orthodontic brackets. Half the discs had sandblasting, hydrofluoric acid, and silane (SB + HF + S), and the other half, phosphoric acid and silane (PA + S). Brackets were debonded using bracket removing pliers, and resin was removed with a 12-fluted carbide bur. The surface was refinished using a porcelain polishing kit, followed by diamond polishing paste. Measurements for surface roughness (Ra), gloss, and color were made before bonding (baseline), after debonding, and after each step of refinishing. Surfaces were also examined by scanning electron microscopy (SEM). Data was analyzed with 2-way ANOVA followed by Tukey HSD tests (alpha = 0.05). The SB + HF + S bonding method increased Ra (0.160 to 1.121 microm), decreased gloss (41.3 to 3.7) and altered color (DeltaE = 4.37; P < .001). The PA + S method increased Ra (0.173 to 0.341 microm; P < .001), but the increase in Ra was significantly less than that caused by the SB + HF + S bonding method (P < . 001). The PA + S method caused insignificant changes in gloss (41.7 to 38.0) and color (DeltaE = 0.50). The measurements and SEM observations showed that changes were fully restored to baseline with refinishing. The PA + S method caused significantly less damage to porcelain than the SB + HF + S method. The refinishing protocol fully restored the porcelain surfaces.