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Sample records for hard coatings evaluated

  1. An Experimental Technique for the Evaluation of Strain Dependent Material Properties of Hard Coatings

    Directory of Open Access Journals (Sweden)

    Shad A. Reed

    2008-01-01

    Full Text Available A novel vibration experiment consisting of a free-free boundary condition, an electromagnetic excitation source, a vacuum chamber, and a laser vibrometer based surface measurement system has been developed that permits high levels of excitation on highly damped specimens with a minimal amount of unwanted systematic error. While some of the aspects of this experiment are not unique, when combined with a processing technique that accounts for the nonlinearities present in the system, this experiment permits, accurate measurement of strain dependent stiffness and damping properties of hard coatings at high strain levels. This procedure has been demonstrated using a titanium beam that has been coated with a free-layer damping treatment of Magnesium Aluminate Spinel. The results indicate that Magnesium Aluminate Spinel has both nonlinear stiffness and damping properties. The stiffness asymptotes to a minimum value around 650 microstrain while the damping is a maximum around 100 microstrain. Additionally, the data contained herein cover a larger strain range for this material than previously reported.

  2. The Evaluation of the Damping Characteristics of a Hard Coating on Titanium

    Directory of Open Access Journals (Sweden)

    Christopher Blackwell

    2007-01-01

    Full Text Available Engine failures due to fatigue have cost the Air Force an estimated $400 million dollars per year over the past two decades. Damping treatments capable of reducing the internal stresses of fan and turbine blades to levels where fatigue is less likely to occur have the potential for reducing cost while enhancing reliability. This research evaluates the damping characteristics of magnesium aluminate spinel, MgO+Al2O3, (mag spinel on titanium plates from an experimental point of view. The material and aspect ratio were chosen to approximate the low aspect ratio blades found in military gas turbine fans. In the past, work has generally been performed on cantilever supported beams, and thus the two-dimensional features of damping were lost. In this study plates were tested with a cantilevered boundary condition, using electrodynamic shaker excitation. The effective test area of each specimen was 4.5 in × 4.5 in. The nominal plate thickness was 0.125 in. Mag spinel was applied to both sides of the plate, at a thickness of 0.01 in, and damping tests were run at room temperature. The effect of the coating was evaluated at the 2nd bending mode (mode 3 and the chord wise bending mode (mode 4. A scanning laser vibrometer revealed the frequency and shape of each mode for the plates. Sine sweeps were used to characterize the damping of the coated and uncoated specimens for the modes tested. The coating increased damping nonlinearly for both modes tested in which the general outcome was similar to that found in beams.

  3. Evaluation of HVOF coatings

    Directory of Open Access Journals (Sweden)

    Mariana Landová

    2016-07-01

    Full Text Available Attention in this paper is devoted to the evaluation of wear coatings deposited using HVOF technology (high velocity oxy-fuel. There were evaluated three types of coatings based on WC-Co (next only 1343, WC-Co-Cr (next only 1350 and Cr3C2-25NiCr (next only 1375. There was assessed adherence of coatings, micro hardness, porosity and the tribological properties of erosive, abrasive, adhesive and wear resistance of coatings in terms of cyclic thermal load. Thanks to wide variety of suitable materials and their combinations, the area of utilization thermally sprayed coatings is very broad. It is possible to deposit coatings of various materials from pure metals to special alloys. The best results in the evaluated properties were achieved at the coating with the label 1375.

  4. Analysis of Hard Thin Film Coating

    Science.gov (United States)

    Shen, Dashen

    1998-01-01

    MSFC is interested in developing hard thin film coating for bearings. The wearing of the bearing is an important problem for space flight engine. Hard thin film coating can drastically improve the surface of the bearing and improve the wear-endurance of the bearing. However, many fundamental problems in surface physics, plasma deposition, etc, need further research. The approach is using electron cyclotron resonance chemical vapor deposition (ECRCVD) to deposit hard thin film an stainless steel bearing. The thin films in consideration include SiC, SiN and other materials. An ECRCVD deposition system is being assembled at MSFC.

  5. Using Hysteretic Energy to Evaluate Damping Characteristics of Hard Coating on Titanium

    Science.gov (United States)

    2013-03-21

    6Al-4V plates and a laser vibrometer to measure plate response to sine sweep excitation. Half-power bandwidth calculations were used to determine...methods measured by laser vibrometer . These methods are accompanied by complex, nonlinear strain evaluation; they are vulnerable to undesired air...displacements of an unforced vibration (Reed 2007). With technology such as Laser Doppler Vibrometry (LDV), these measurements can be made quite easily. The

  6. Tribological characterization of thin, hard coatings

    Energy Technology Data Exchange (ETDEWEB)

    Hogmark, S. (Uppsala Univ., Dept. of Technology, Materials Science Div. (Sweden)); Hedenqvist, P. (Uppsala Univ., Dept. of Technology, Materials Science Div. (Sweden))

    1994-12-01

    The use of thin, hard coatings in tribological applications has become more widespread. Thus the need to fully understand the relationships between the intrinsic properties of the coating, the properties of the coating/substrate composite and the tribological performance of the composite in different tribological systems has become more pressing. The present paper contributes to this effort by presenting and discussing the use of a selected number of physical and mechanical tests to obtain a general characterization of the tribological properties of a coated material: its tribological profile. The tribological tests include dry sliding wear, solid particle erosion and microabrasion. Even if the emphasis of the present paper is put on tribological characterization of thin, hard coatings, some of the current techniques frequently employed to characterize some of the more general properties of a coating, e.g. thickness, hardness, adhesion, residual stress state, etc., are treated. Examples from tribology profile determination and general characterization are collected from PVD and CVD coating systems. (orig.)

  7. Induction surface hardening of hard coated steels

    DEFF Research Database (Denmark)

    Pantleon, Karen; Kessler, Olaf; Hoffmann, Franz

    1999-01-01

    -process is the high deposition temperature, consequently the properties of steel substrates are negatively influenced. Therefore, a subsequent heat treatment of the coated steels is necessary to restore the properties of steels ready for operation. Induction surface hardening is used as a method of heat treatment......, the scratch test is used to estimate critical loads for cohesive and adhesive failure of the coatings. Additionally, distortion measurements are carried out. The results emphasize the advantage of induction surface hardening as a method of subsequent heat treatment of CVD-coated steels....... after the deposition of TiN hard coatings on steel substrates. Influences of both the coating properties and the substrate properties are discussed in dependence on the parameters of induction heating. Thereby the heating time, heating atmosphere and the power input into the specimen are changed...

  8. Evaluation of microstructure and micro-hardness of 410L SS coatings fabricated using laser assisted cold spraying: process development

    CSIR Research Space (South Africa)

    Mathebula, TE

    2014-11-01

    Full Text Available , contaminating and erosive environments which accelerate the degradation of these components. Surface coatings are generally used to protect and prolong the lifetime of the parts. Laser Assisted Cold Spray (LACS) is a relatively new surface coating process which...

  9. Effect of bond coat and preheat on the microstructure, hardness, and porosity of flame sprayed tungsten carbide coatings

    Science.gov (United States)

    Winarto, Winarto; Sofyan, Nofrijon; Rooscote, Didi

    2017-06-01

    Thermally sprayed coatings are used to improve the surface properties of tool steel materials. Bond coatings are commonly used as intermediate layers deposited on steel substrates (i.e. H13 tool steel) before the top coat is applied in order to enhance a number of critical performance criteria including adhesion of a barrier coating, limiting atomic migration of the base metal, and corrosion resistance. This paper presents the experimental results regarding the effect of nickel bond coat and preheats temperatures (i.e. 200°C, 300°C and 400°C) on microstructure, hardness, and porosity of tungsten carbide coatings sprayed by flame thermal coating. Micro-hardness, porosity and microstructure of tungsten carbide coatings are evaluated by using micro-hardness testing, optical microscopy, scanning electron microscopy, and X-ray diffraction. The results show that nickel bond coatings reduce the susceptibility of micro crack formation at the bonding area interfaces. The percentage of porosity level on the tungsten carbide coatings with nickel bond coat decreases from 5.36 % to 2.78% with the increase of preheat temperature of the steel substrate of H13 from 200°C to 400°C. The optimum hardness of tungsten carbide coatings is 1717 HVN in average resulted from the preheat temperature of 300°C.

  10. Analysis of hardness of nanocrystalline coatings of aluminum-rich ...

    Indian Academy of Sciences (India)

    The Vicker hardness was obtained by the effective model of indentation. It was observed that the hardness of the coatings decreases from 22.8–9.5 GPa with an increased nitrogen content from 1.5–4.5 sccm. Subsequently, the hardness increased to 22.1 GPa by increasing nitrogen to 6 sccm. The behavior of hardness with ...

  11. Application of hard coatings for blanking and piercing tools

    DEFF Research Database (Denmark)

    Podgornik, B.; Zajec, B.; Bay, Niels

    2011-01-01

    The aim of the present investigation was to examine the possibility of reducing lubrication and replacing expensive tungsten carbide material in blanking/piercing through introduction of hard tool coatings. Results show that hard PVD coatings can be successfully used in blanking/piercing...... critical value under dry friction conditions and leads to tool failure. Therefore, at present oxidation and temperature resistant hard coatings can give improved wear resistance of stamping tools, but elimination of lubricants in blanking and piercing processes is still not feasible....

  12. Microstructures, hardness and bioactivity of hydroxyapatite coatings

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2014-10-01

    Full Text Available spraying techniques are well founded. In this paper, HAP was coated on Ti–6Al–4V using direct laser melting (DLM) process. This process, unlike the traditional coating processes, is able to achieve coatings with good metallurgical bonding and little...

  13. Self-lubricating Hard Coatings for Extreme Environment Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This program will develop low friction hard coatings for lubricating mechanical and tribological components used for exploring Mars, the Moon, asteroids, comets and...

  14. Highly Damping Hard Coatings for Protection of Titanium Blades

    National Research Council Canada - National Science Library

    Movchan, Boris A; Ustinov, Anatolii I

    2005-01-01

    Sn-Cr-MgO system is used as an example to show the basic capability to produce by EBPVD protective metal-ceramic coatings with a high adhesion strength, high values of hardness and damping capacity...

  15. Mechanical behaviour of hard PVD multilayered coatings

    Energy Technology Data Exchange (ETDEWEB)

    Harry, E. [Lyon-1 Univ., Villeurbanne (France). Lab. des Sciences and Ingenierie des Surfaces; Ignat, M.; Pauleau, Y. [ENSEEG, F-38402, Saint Martin d' Heres (France); Rouzaud, A.; Juliet, P. [CEA, F-38054, Grenoble (France)

    2000-03-01

    The aim of this work was to investigate the cracking behaviour and adhesion of tungsten-carbon-based multilayered coatings deposited on steel substrates by magnetron sputtering. Three-point bending experiments were performed on the coating-on-substrate systems until failure of the film. The systems were also strained uniaxially with a microtensile device adapted to a scanning electron microscope. The mechanical response is analysed from the evolution of the crack density in the coating and the fracture toughness. The results show that the rupture properties of the multilayered coatings are correlated to the film thickness and arrangement of the elementary layers. Scratch experiments on the systems revealed a strong adhesion of the multilayered coatings on steel substrates, and delamination at layer interfaces. Thus, graded coatings appear to be more attractive for mechanical applications. (orig.)

  16. Raman microscopic studies of PVD deposited hard ceramic coatings

    CERN Document Server

    Constable, C P

    2000-01-01

    GPa were deposited onto SS and HSS substrates. Subsequent Raman measurements found a correlation coefficient of 0.996 between Raman band position and stress (determined via XRD methods). In addition, there was also a similar correlation coefficient observed between hardness and Raman shift (cm sup - sup 1). The application of mechanical stresses on a TiAICrN coating via a stress rig was investigated and tensile and compressive shifts were observed. stresses caused by the scratching process. These shifts were found to be the largest at the edges of scratches. The Raman mapping of 'droplets', a defect inherent to PVD deposition processes, found that higher compressive stresses and large amounts of disorder occurred for coating growth onto droplets. Strategies designed to evaluate the ability of Raman microscopy to monitor the extent of real wear on cutting tools were evaluated. The removal of a coating layer and subsequent detection of a base layer proved successful. This was then expanded to real wear situatio...

  17. LARGE AREA FILTERED ARC DEPOSITION OF CARBON AND BORON BASED HARD COATINGS

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Rabi S.

    2003-12-05

    This document is a final report covering work performed under Contract No. DE-FG02-99ER82911 from the Department of Energy under a SBIR Phase II Program. Wear resistant, hard coatings can play a vital role in many engineering applications. The primary goal of this project was to develop coatings containing boron and carbon with hardness greater than 30 GPa and evaluate these coatings for machining applications. UES has developed a number of carbon and boron containing coatings with hardness in the range of 34 to 65 GPa using a combination of filtered cathodic arc and magnetron sputtering. The boron containing coatings were based on TiB2, TiBN, and TiBCN, while the carbon containing coatings ere TiC+C and hydrogen free diamond-like-carbon. Machining tests were performed with single and multilayer coated tools. The turning and milling tests were run at TechSolve Inc., under a subcontract at Ohio State University. Significant increases in tool lives were realized in end milling of H-13 die steel (8X) and titanium alloy (80%) using the TiBN coating. A multilayer TiBN/TiN performed the best in end-milling of highly abrasive Al-Si alloys. A 40% increase in life over the TiAlN benchmark coating was found. Further evaluations of these coatings with commercialization partners are currently in progress.

  18. Influence of Hard Tool Coatings on Process of Stamping

    DEFF Research Database (Denmark)

    Zajec, Bostjan; Podgornik, Bojan; Bay, Niels

    2007-01-01

    of tool life can be achieved by proper selection of tool materials and possible coatings. In mass production the tools are usually made of WC, which however, results in expensive tools and long time of delivery. The aim of the present investigation was to determine the influence of different tool...... materials and possible hard coatings as alternative tool materials. For this purpose the blanking/punching process was first analyzed by a numerical model and based on the results four different tool materials and three hard coatings were included in the investigation and tested in a model test rig as well...... as in a real blanking/punching operation. The tool materials included were WC, BRM, ASP and S390. These materials were tested uncoated as well as coated, with the commercial coatings: Balinit B, Balinit Alcrona and Balinit Hardlube, respectively....

  19. Hardness and microplasticity of nanocrystalline and amorphous calcium phosphate coatings

    Science.gov (United States)

    Ievlev, V. M.; Kostyuchenko, A. V.; Darinskii, B. M.; Barinov, S. M.

    2014-02-01

    The hardness of thin (1.0-4.0 μm) hydroxyapatite coatings with different structures (nanocrystalline, amorphous-crystalline, and amorphous) grown by rf magnetron sputtering on Ti and Si plates has been studied using the nanoindentation method. All the grown structures are characterized by the strain which has reversible and irreversible components. The hardness of nanocrystalline coatings (about 10 GPa) corresponds to the average hardness of hydroxyapatite single crystals. The structure of nanocrystalline coatings in the indentation zone and outside it has been investigated and changes in the structure under the indenter have been revealed using high-resolution transmission electron microscopy. From a comparison of the hardnesses of coatings with different structures and based on an analysis of the intragranular structure, it has been assumed that the plastic deformation occurs according to a dislocation-free mechanism. The plastic deformation is interpreted in terms of the cluster representation of the hydroxyapatite structure and amorphous calcium phosphates of the same elemental composition and cluster-boundary sliding during the deformation.

  20. Analysis of hardness of nanocrystalline coatings of aluminum-rich

    Indian Academy of Sciences (India)

    acknowledge the technical assistance of Ayesha Margarita. Courrech Arias. References. Amini Mashhadi H, Kennedy G, Tanaka S and Hokamoto K 2011. Physica B 406 1211. Bunshah R F 2001 Handbook of hard coatings (New York: William. Andrew Publishing/Noyes). Chawla V, Chandra R and Jayaganthan R 2010 J.

  1. Microindentation hardness testing of coatings: techniques and interpretation of data

    Science.gov (United States)

    Blau, P. J.

    1986-09-01

    This paper addresses the problems and promises of micro-indentation testing of thin solid films. It has discussed basic penetration hardness testing philosophy, the peculiarities of low load-shallow penetration tests of uncoated metals, and it has compared coated with uncoated behavior so that some of the unique responses of coatings can be distinguished from typical hardness versus load behavior. As the uses of thin solid coatings with technological interest continue to proliferate, microindentation testing methodology will increasingly be challenged to provide useful tools for their characterization. The understanding of microindentation response must go hand-in-hand with machine design so that the capability of measurement precision does not outstrip our abilities to interpret test results in a meaningful way.

  2. Chromium nitride-silver self-lubricating nanoporous hard coatings

    Science.gov (United States)

    Mulligan Christopher P

    The focus of this thesis research is to explore a new approach to adaptive solid lubrication using nanoporous hard coatings. To investigate this approach, I deposited prototype coatings for study consisting of a hard chromium nitride (CrN) matrix co-deposited with a lubricious silver (Ag) phase by reactive magnetron co-sputtering. The idea is to exploit the relative immiscibility of the two phases to create nanocomposite structures with intrinsic lubricant transport properties enabled by the presence of the nanopores. Specifically, I develop the scientific understanding of the critical growth parameters that govern nanocomposite structural evolution which in turn control mechanical properties, solid lubricant diffusion, and tribological response. Mechanical properties were analyzed by both micro and nanoindentation measurements for the composites as a function of Ag aggregate morphology. For Ts ≤ 500°C, hardness as measured by nanoindentation into the surface is relatively uniform giving values of 14.6, 13.6, and 14.3 GPa for Ts = 300, 400, and 500°C respectively. For Ts > 500°C, the cross-sectional microhardness increases with T s from 16.5 to 19.7 to 24.3 GPa for Ts = 500, 600, and 700°C, respectively, which is attributed to a decrease in the effective Ag concentration associated with temperature activated segregation. The average hardness for pure CrN samples is 23.8 and 27.5 GPa as measured by surface nanoindentation and cross-sectional microindentation, respectively. Lubricant transport behavior was characterized by a series of vacuum annealing experiments. Vacuum annealing experiments at Ta = 425, 525, and 625°C show that Ag diffuses to the coating surface to form lubricious surface aggregates and that the rate for Ag lubricant transport increases with increasing DeltaT (Ta - Ts) for Ta > Ts, as determined by quantitative electron microscopy surface analyses. However, the Ag remains in the CrN matrix for Ta self-lubricating properties and tribological

  3. Rolling-contact fatigue resistance of hard coatings on bearing steels.

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, A.

    1999-08-18

    Ball- and roller-bearings of the 21st Century are expected to perform better and last longer while operating under more stringent conditions than before. To meet these great expectations, researchers have been constantly exploring new bearing designs or refining existing ones, optimizing microstructure and chemistry of bearing materials, and alternatively, they have been considering the use of thin hard coatings for improved bearing performance and durability. Already, some laboratory tests have demonstrated that hard nitride, carbide (such as TiN, TiC, etc.) and diamondlike carbon (DLC) coatings can be very effective in prolonging the fatigue lives of bearing steels. This paper provides an overview of the recent developments in hard coatings for bearing applications. Previous studies have demonstrated that thin, hard coatings can effectively prolong the fatigue lives of bearing steel substrates. In particular, thinner hard coatings (i.e., 0.2 - 1 {micro}m thick) provide exceptional improvements in the fatigue lives of bearing steel substrates. In contrast, thicker hard coatings suffer micro fracture and delamination when tested under high contact stresses, hence are ineffective and may even have a negative effect on bearing life. Overall, it was concluded that thin hard coatings may offer new possibilities for bearing industry in meeting the performance and durability needs of the 21st Century.

  4. Application of Hard Coatings for Improved Tribological Performance of Blanking and Piercing Tools

    DEFF Research Database (Denmark)

    Podgornik, B.; Zajec, B.; Bay, Niels

    2010-01-01

    The aim of the present investigation was to examine the possibility of reducing lubrication and replacing expensive tungsten carbide material in blanking/piercing through introduction of hard tool coatings. Results show that hard PVD coatings can be successfully used in blanking/piercing...... critical value under dry friction conditions and leads to tool failure. Therefore, at present oxidation and temperature resistant hard coatings can give improved wear resistance of stamping tools, but elimination of lubricants in blanking and piercing processes is still not feasible....

  5. Evaluation of Manganese Phosphate Coatings.

    Science.gov (United States)

    1984-02-01

    D-AiD9 434 EVALUATION OF MANGANESE PHOSPHATE COTINGS(I) ARMY v/1 ARMAMENT RESEARCH R D DEVELO MENT CENTER IdATERYL lET NY I LARGE CALIBER WEAPON...5Y IIARS 163 TECHNICAL REPORT ARLCB-TR- 64003 EVALUATION OF MANGANESE PHOSPHATE COATINGS R. A. FARRARA FEBRUARY 1984 N US ARMY ARMAMENT RESEARCH AND...84003 _____________ 4. TTLE and -bitle)5. TYPE OF REPORT & PERIOD COVERED EVALUATION OF MANGANESE PHOSPHATE COATINGS Final 6. PERFORMING ORG. REPORT

  6. The structure and formation of functional hard coatings: a short review

    Directory of Open Access Journals (Sweden)

    Diciuc Vlad

    2017-01-01

    Full Text Available Turning tools come in different shapes and sizes, geometry, base material and coating, according to their destination. They are widely used both for obtaining parts and for machinability tests. In this paper a short review about high-speed steel (HSS turning tools and their coatings is presented. Hard coatings formed on the tool material should be functional depending on the tool final application. Requirements for hard coatings and technological problems for layer formation on the real cutting tool are discussed.

  7. Designing ultraviolet curing of multifunctional (meth)acrylate hard coats

    Science.gov (United States)

    Wen, Mei

    Ultraviolet (UV) curing rapidly converts multifunctional (meth)acrylate liquid monomers into highly cross-linked, impervious, hard polymeric coatings at ambient temperature. This solidification process occurs by free-radical cross-linking polymerization. To achieve a better design of this process, it is desirable to have high conversion of functional groups, low stress, adequate mechanical properties, and low costs. To approach this design goal, the following modeling and experimental work was carried out. Firstly, a kinetic model was developed to simulate radical trapping. This model predicts a peak in the concentration of active radicals and a monotonic rise of the concentration of trapped radicals during polymerization. It also predicts a decrease in the fraction of trapped radicals at a given conversion as the UV light intensity is raised. Secondly, a kinetic gelation model, in which reaction occurs locally on a lattice, was developed. Unlike previous such models, this model accounts for free radical reaction time more accurately. It was found that a more uniform distribution of reacted sites leads to a favored propagation at a given conversion. Moreover, radical trapping and termination were found to shorten the kinetic chain length and to lower the asymptotic conversion reached when initiators are exhausted. Thirdly, elastic modulus evolution was simulated with a rigidity percolation model, in which bonds created by free-radical polymerization are represented as rigidly jointed beams. Simulations show that modulus of a network depends on the connectivity between monomer units as well as bonding structure. Finally, experimental determination of volume shrinkage of a sandwiched film was measured with a dynamic mechanical analyzer probe. A faster reaction causes more severely delayed volume shrinkage from the thermodynamic equilibrium volume required by the reaction. Nevertheless, volume shrinks more when the shrinkage of the thermodynamic volume rises. In

  8. Amorphous self-lubricant MoS2-C sputtered coating with high hardness

    Science.gov (United States)

    Gu, Lei; Ke, Peiling; Zou, Yousheng; Li, Xiaowei; Wang, Aiying

    2015-03-01

    MoS2-C coatings with various carbon contents were deposited by direct current magnetron sputtering. Carbon concentration (from 40.9 at.% to 73.1 at.%) within the coatings was controlled by varying the number of MoS2 plates bonded to the carbon targets. Ti interlayer fabricated by a hybrid high power impulse magnetron sputtering was used to obtain excellent adhesion. By sputtering the composite target, the deposited coatings exhibited a typical amorphous structure feature which contributed to the high hardness of the coatings. Meanwhile, the friction coefficient of the composite coating was lower than 0.1 in the ambient air and exhibited high wear resistance. Furthermore, the composite coatings exhibited an increasing hardness (from 7.0 to 10.8 GPa) with increasing carbon content.

  9. Hard, infrared black coating with very low outgassing

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmenko, P J; Behne, D M; Casserly, T; Boardman, W; Upadhyaya, D; Boinapally, K; Gupta, M; Cao, Y

    2008-06-02

    Infrared astronomical instruments require absorptive coatings on internal surfaces to trap scattered and stray photons. This is typically accomplished with any one of a number of black paints. Although inexpensive and simple to apply, paint has several disadvantages. Painted surfaces can be fragile, prone to shedding particles, and difficult to clean. Most importantly, the vacuum performance is poor. Recently a plasma enhanced chemical vapor deposition (PECVD) process was developed to apply thick (30 {micro}m) diamond-like carbon (DLC) based protective coatings to the interior of oil pipelines. These DLC coatings show much promise as an infrared black for an ultra high vacuum environment. The coatings are very robust with excellent cryogenic adhesion. Their total infrared reflectivity of < 10% at normal incidence approaches that of black paints. We measured outgas rates of <10{sup -12} Torr liter/sec cm{sup 2}, comparable to bare stainless steel.

  10. Radiation Hard Multi-Layer Optical Coatings Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Next generation space telescopes require advanced optical coatings to provide low loss transmission of light in a variety of spectral ranges and protect optical...

  11. Radiation Hard Multi-Layer Optical Coatings Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Next-generation space telescopes require advanced optical coatings to provide low-loss polarization-preserving transmission/reflection of light in a variety of...

  12. The role of PECVD hard coatings on the performance of industrial tools

    Directory of Open Access Journals (Sweden)

    Meysam Zarchi

    2014-03-01

    Full Text Available The advantages of the application of hard coatings, which are well knownfor cutting tools, are to a much lesser extent explored for casting, extrusion, molding and forming tools. Increasing the lifetime of these tools is an important task in surface engineering because of complex loading conditionsand often complicated tool geometry. The plasma-enhanced chemical vapor deposition (PECVD technique is well suited to deposit hard coatings onto large dies and moulds. The aim of this study was to discuss deposition processes suitable for coating of the often large three-dimensional molds and dies used in metal forming. Furthermore, results obtained using different hard coatings in industrial applications for several case studies like aluminum pressure die-casting; plastics injection molding and sheet metal forming are presented and discussed. For best coating performance, a careful optimization of both substrate pretreatment and coating deposition is necessary. The plasma-enhanced chemical vapor deposition (PECVD technique shows advantages for these applications because of the high flexibility in pre-treatment using chemical etching and plasma-nitriding, because of its ability to coat large complexly shaped tools and because of the possibility of deposition of low-chlorine containing low-friction coatings.

  13. Multilayer coating facility for the HEFT hard x-ray telescope

    DEFF Research Database (Denmark)

    Cooper-Jensen, Carsten P.; Christensen, Finn Erland; Chen, Hubert

    2001-01-01

    A planar magnetron sputtering facility has been established at the Danish Space Research Institute (DSRI) for the production coating of depth graded multilayers on the thermally slumped glass segments which form the basis for the hard X-ray telescope on the HEFT balloon project. The facility...... is capable of coating 20-45 mirrors segments in each run. The coatings are optimized W/Si coatings. The paper describes the facility, the results of the calibration and presents data for the X-ray testing of flight mirrors....

  14. Critical review of claims for ultra-hardness in nanocomposite coatings

    Science.gov (United States)

    Fischer-Cripps, A. C.; Bull, S. J.; Schwarzer, N.

    2012-05-01

    Claims for ultra-hardness (H ≈ 100 GPa) in nanocomposite coatings are critically examined in terms of the experimental evidence first presented in 1999 and theoretical support published over the past 10 years. It is shown that the results of experimental work cannot be validated, and that there are many unresolved issues associated with the supporting theoretical arguments. Using the methods outlined by the authors, whose work is reviewed here, but with more precise application of the equations involved, and reading directly from their reported relationships between Y and H, the best estimate of the hardness for the materials under consideration appears to be of the order of ≈55 GPa. This estimate is validated by actual measurements on a diamond sample and super-hard coatings, and finite element computations in comparison with experimental results for ultra-hard coatings. It is shown that the conclusions of the work being reviewed do not stand up to scrutiny and that the hardness of the ultra-hard coatings is most likely over-estimated by a factor of ≈2.

  15. Study of Selected Properties of Thermally Sprayed Coatings Containing WC and WB Hard Particles

    Directory of Open Access Journals (Sweden)

    Brezinová Janette

    2016-12-01

    Full Text Available The paper presents results of research of the essential characteristics of two kinds of advanced coatings applied by HVOF technology. One studied coating: WB-WC-Co (60-30-10% contains two types of hard particles (WC and WB, the second coating is eco-friendly alternative to the previously used WC-based coatings, called “green carbides” with the composition WC-FeCrAl (85-15%. In green carbides coating the heavy metals (Co, Ni, NiCr forming the binding matrix in conventional wear-resistant coatings are replaced by more environmentally friendly matrix based on FeCrAl alloy. On the coatings was carried out: metallographic analysis, measurement of thickness, micro-hardness, adhesion, resistance to thermal cyclic loading and adhesive wear resistance (pin-on-disk test. One thermal cycle consisted of heating the coatings to 600°C, dwell for 10 minutes, and subsequently cooling on the still air. The number of thermal cycles: 10. The base material was stainless steel AISI 316L, pretreatment prior to application of the coating: blasting with white corundum, application device JP-5000.

  16. Short-Pulse Laser Sintering of Multilayer Hard Metal Coatings: Structure and Wear Behavior

    Science.gov (United States)

    Kharanzhevskiy, Evgeny; Ipatov, Alexey; Nikolaeva, Irina; Zakirova, Raushaniya

    2015-06-01

    This paper reports on the phase composition and properties of multilayer hard metal coatings deposited on steel by a process variant of Selective laser melting (SLM). The process is based on layer-wise short-pulse laser sintering of high-dispersive WC-Co powder on a steel substrate. High temperature in the molten zone and chemical interaction with the substrate explain high level of adhesion strength between the coating and the substrate. The technique allows obtaining both high quality hard-metal multilayer gradient coatings with thickness up to 200 μm, density near to the theoretical density (TD), hardness up to 21 GPa and complex 3D objects by layer-wise powder based process such as SLM.

  17. Young modulus dependence of nanoscopic friction coefficient in hard coatings

    OpenAIRE

    Riedo, E.; Brune, H.

    2003-01-01

    We present an atomic force microscope study of nanoscopic sliding friction on diamond, diamond-like carbon, and on three CrN thin films with varying hardness obtained by different growth temperatures. For the CrN films, we show that the changes in the friction coefficient can be traced back to variations of the Young modulus. More generally, we show for all samples investigated and in wearless regime, that the nanoscopic friction coefficient is directly linked to the Young modulus. (C) 2003 A...

  18. Corrosion behavior of HVOF sprayed hard face coatings in alkaline-sulfide solution

    Science.gov (United States)

    Li, Shenhou; Guo, Zhixing; Xiong, Ji; Lei, Yong; Li, Yuxi; Tang, Jun; Liu, Junbo; Ye, Junliu

    2017-09-01

    The paper focuses on the corrosion behavior of high velocity oxygen fuel (HVOF) sprayed WC-17Co, WC-10Co-4Cr, Cr3C2-25NiCr coatings in alkaline-sulfide solution (S2-, 0.2 ml/L, pH = 10). Eighteen days of immersion test is carried out and corrosion rate analysis shows that the Cr3C2-NiCr coating of low porosity exhibits the best corrosion resistance. In alkaline-sulfide solutions, porosity, passive film and microgalvanic between hard phase and binder phase have significant effect on the corrosion behavior of coatings. The corrosion mainly occurs in binder phase from SEM, though WO3, WS2, Cr2S3 are detected in XPS. In WC-17Co coating, the binder phase Co transforms to Co oxides and serious corrosion can be observed in binder phase. WC-10Co-4Cr coatings suffer localized corrosion since galvanic corrosion occurs between locations with different solubilities of W in Co binder. Cr3C2-25NiCr coating shows slight corrosion with the formation of NiS/Ni2O3/Cr2O3from the binder and Cr2S3 from the hard phase. The results are verified by the polarization curves, which show the longest passive region and lowest Icorrosion of Cr3C2-25NiCr coating.

  19. Depth-resolved X-ray residual stress analysis in PVD (Ti, Cr) N hard coatings

    CERN Document Server

    Genzel, C

    2003-01-01

    Physical vapour deposition (PVD) of thin hard coatings on TiN basis is usually performed at rather low temperatures (T sub D < 500 C) far from thermal equilibrium, which leads to high intrinsic residual stresses in the growing film. In contrast to the extrinsic thermal residual stresses which can easily be estimated from the difference of the coefficients of thermal expansion between the substrate and the coating, a theoretical prediction of the intrinsic residual stresses is difficult, because their amount as well as their distribution within the film depend in a very complex way on the deposition kinetics. By the example of strongly fibre-textured PVD (Ti, Cr)N coatings which have been prepared under defined variation of the deposition parameters in order to adjust the residual stress distribution within the coatings, the paper compares different X-ray diffraction techniques with respect to their applicability for detecting residual stresses which are non-uniform over the coating thickness. (orig.)

  20. Super hard WC-Cr composite coatings. An approach to potential wear applications

    Energy Technology Data Exchange (ETDEWEB)

    Sancakoglu, Orkut; Celik, Erdal [Dokuz Eylul Univ., Izmir (Turkey). Dept. of Metallurgy and Materials Engineering

    2016-11-01

    In this study, submicron (APS = 200 nm) tungsten carbide (WC) ceramic particles were co-deposited with chromium metal (Cr) via electro-co-deposition system to fabricate WC-Cr metal matrix composite coatings. Instead of traditional electrodeposition cells, a new system was designed and coatings were fabricated using this system. Phase identifications of the coatings were performed by X-ray diffractometry (XRD) and surface morphologies were investigated using energy dispersive X-ray spectroscopy (EDS) with attached scanning electron microscope (SEM). Hardness values of the coatings were performed under 980.7 mN applied load using a microhardness tester. It was concluded that WC ceramic particles were physically adsorbed on the cathode surface and formed a composite structure with metal Cr and co-deposition of submicron sized ceramic particles with metals via electrodeposition system was strictly successful. In addition, with respect to the reference coatings, WC reinforced composite coatings depict an increased hardness up to twice its value. Frequency, as a parameter of pulse current, is determined as an effective parameter in co-deposition.

  1. Characterization of Pulse Reverses Electroforming on Hard Gold Coating.

    Science.gov (United States)

    Byoun, Young-Min; Noh, Young-Tai; Kim, Young-Geun; Ma, Seung-Hwan; Kim, Gwan-Hoon

    2018-03-01

    Effect of pulse reverse current (PRC) method on brass coatings electroplated from gold solution was investigated by various plating parameters such as plating duration, the anodic duty cycle, the anodic current density and the cathodic current density. The reversed current results in a significant change in the morphology of electrodeposits, improvement of the overall current efficiency and reduction of deposit porosity. With longer pulses, hemispherical surface features are generated, while larger grains result from shorter pulse widths. The porosity of the plated samples is found to decrease compared with results at the same time-average plating rate obtained from DC or Pulse plating. A major impediment to reducing gold later thickness is the corrosion of the underlying substrate, which is affected by the porosity of the gold layer. Both the morphology and the hydrogen evolution reaction have significant impact on porosity. PRC plating affect hydrogen gold and may oxidize hydrogen produced during the cathodic portion of the waveform. Whether the dissolution of gold and oxidation of hydrogen occur depends on the type of plating bath and the plating conditions adapted. In reversed pulse plating, the amount of excess near-surface cyanide is changed after the cathodic current is applied, and the oxidation of gold under these conditions has not been fully addressed. The effects of the current density, pulse-reverse ratio and brightener concentration of the electroplating process were investigated and optimized for suitable performance.

  2. Correlation between hardness and water absorption properties of Saudi kaolin and white clay geopolymer coating

    Science.gov (United States)

    Ramasamy, Shamala; Abdullah, Mohd Mustafa Al Bakri; Huang, Yue; Hussin, Kamarudin; Wang, Jin; Shahedan, Noor Fifinatasha

    2017-09-01

    Geopolymer is an uprising technology that is being studied worldwide. Geopolymer raw materials are basically aluminosilicate source materials. However, this technology is yet to infiltrate into pipelines and coating industries which initiated our research idea. The idea of creating universal geopolymer based coating material is mainly to help oil and gas industry reduce its maintenance cost. Kaolin based geopolymer paste was coated on glass reinforced epoxy (GRE) substrates which are majorly used as pipeline material in the oil and gas industry at Saudi Arabia. Kaolin and white clay was chosen as raw material to study the possibilities of utilizing underused aluminosilicate raw materials for geopolymer coating. To obtain suitable formulation, Na2SiO3/NaOH ratio was varied from 0.40 untill 0.60 while other parameters such as solid/liquid ratio and NaOH molarity were kept constant at values as per previous works. Geopolymer coated GRE substrates were then subjected to water absorption, flexural strength and hardness test to validate our findings. Water absorption is a crucial test as for coating materials which justifies the pratical usability of the coating product. Upon testing, kaolin and white clay based geopolymer coating each shows promising properties at Na2SiO3/NaOH ratio of 0.45 and 0.50 each.

  3. Evaluation of irradiated coating material specimens

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yong Jin; Nam, Seok Woo; Cho, Lee Moon [RCS Korea Co., Ltd., Seoul (Korea, Republic of)

    2007-12-15

    Evaluation result of irradiated coating material specimens - Coating material specimens radiated Gamma Energy(Co 60) in air condition. - Evaluation conditions was above 1 X 10{sup 4} Gy/hr, and radiated TID 2.0 X 10{sup 6} Gy. - The radiated coating material specimens, No Checking, Cracking, Flaking, Delamination, Peeling and Blistering. - Coating system at the Kori no. 1 and APR 1400 Nuclear power plant, evaluation of irradiated coating materials is in accordance with owner's requirement(2.0 X 10{sup 6} Gy)

  4. The hardness of the hydroxyapatite-titania bilayer coatings by microindentation and nanoindentation testing

    Science.gov (United States)

    SIDANE, Djahida; KHIREDDINE, Hafit; YALA, Sabeha

    2017-12-01

    The aim of this paper is to investigate the effect of the addition of titania (TiO2) inner-layer on the morphological and mechanical properties of hydroxyapatite (HAP) bioceramic coatings deposited on 316L stainless steel (316L SS) by sol-gel method in order to improve the properties of hydroxyapatite and expand its clinical application. The addition of TiO2 as sublayer of a hydroxyapatite coating results in changes in surface morphology as well as an increase of the microhardness. The deposition of the inner-layer provides the formation of new types of hydroxyapatite coatings at the same condition of annealing. This represents an advantage for the various applications of the hydroxyapatite bioceramic in the medical field. Classical hardness measurements conducted on the coated systems under the same indentation load (10g) indicated that the microhardness of the HAP coating is improved by the addition of TiO2 inner-layer on the 316L stainless steel substrate. The hardness values obtained from both classical tests in microindentation and the continuous stiffness measurement mode in nanoindentation are slightly different. This is because nanoindentation is more sensitive to the surface roughness and the influence of defects that could be present into the material. Moreover, nanoindentation is the most useful method to separate the contribution of each layer in the bilayer coatings. In this study, the hardness is comparable with those reported previously for pure HAP ceramics (1.0–5.5 GPa) which are close to the properties of natural teeth.

  5. MUTUAL SOLUBILITY ОF CARBIDES WITHIN MULTICOMPONENT DIFFUSIVE COATINGS ОN HARD ALLOYS

    Directory of Open Access Journals (Sweden)

    A. A. Shmatov

    2008-01-01

    Full Text Available An optimization of powder mixtures has been performed with respect to wear resistance of  diffusive carbide coatings on hard alloy Т15К6 (79% WC, 15% TiC and 6% Co for four three-component systems, viz. Cr–Ti–V, Cr–V–Mo, Cr–Ti–Mo and Cr–V–Nb,. The «composition-properties» diagrams have been plotted using the obtained mathematical models. Optimum three-component diffusive saturation of a hard alloy using carbide-forming elements permits to increase its service life by the factor of 2.2–3.1 as compared with one-component saturation. This significant improvement of wear resistance of three-component diffusive carbide coatings is due to formation of heterogeneous microstructure containing complex alloyed carbides of IV-VI-group metals with 2–30% mutually soluble one- or two- saturating elements. 

  6. Electrodeposition of Nanocrystalline Cobalt Phosphorous Coatings as a Hard Chrome Alternative

    Science.gov (United States)

    2014-11-01

    Strength, wear, ultimate tensile strength   Density   Coefficient of friction *Smaller grain size impedes dislocation movement and...3. Porosity  4. Hardness  5. Grain Size  6. Ductility  7. Stress  8. Fatigue  9. Coating Integrity  10. Corrosion (B117)  11... Corrosion (SO2)  12. Corrosion (Beach)  13. Corrosion (OCP)  14. Adhesion  15. HE  16. HE (No Bake)  17. Fluid Compatibility  18. HRE  19

  7. Sealing of hard CrN and DLC coatings with atomic layer deposition.

    Science.gov (United States)

    Härkönen, Emma; Kolev, Ivan; Díaz, Belén; Swiatowska, Jolanta; Maurice, Vincent; Seyeux, Antoine; Marcus, Philippe; Fenker, Martin; Toth, Lajos; Radnoczi, György; Vehkamäki, Marko; Ritala, Mikko

    2014-02-12

    Atomic layer deposition (ALD) is a thin film deposition technique that is based on alternating and saturating surface reactions of two or more gaseous precursors. The excellent conformality of ALD thin films can be exploited for sealing defects in coatings made by other techniques. Here the corrosion protection properties of hard CrN and diamond-like carbon (DLC) coatings on low alloy steel were improved by ALD sealing with 50 nm thick layers consisting of Al2O3 and Ta2O5 nanolaminates or mixtures. In cross sectional images the ALD layers were found to follow the surface morphology of the CrN coatings uniformly. Furthermore, ALD growth into the pinholes of the CrN coating was verified. In electrochemical measurements the ALD sealing was found to decrease the current density of the CrN coated steel by over 2 orders of magnitude. The neutral salt spray (NSS) durability was also improved: on the best samples the appearance of corrosion spots was delayed from 2 to 168 h. On DLC coatings the adhesion of the ALD sealing layers was weaker, but still clear improvement in NSS durability was achieved indicating sealing of the pinholes.

  8. Superior hardness and Young's modulus of low temperature nanocrystalline diamond coatings

    Energy Technology Data Exchange (ETDEWEB)

    Cicala, G., E-mail: grazia.cicala@ba.imip.cnr.it [CNR-IMIP Bari, Via G. Amendola 122/D, 70126 Bari (Italy); Magaletti, V. [ALTA S.p.A., via Gherardesca 5, 56121 Ospedaletto (Pisa) (Italy); Senesi, G.S. [CNR-IMIP Bari, Via G. Amendola 122/D, 70126 Bari (Italy); Carbone, G. [DIMeG-Politecnico di Bari Viale Japigia 182, 70126 Bari (Italy); Altamura, D.; Giannini, C. [CNR-IC Bari, Via G. Amendola 122/D, 70126 Bari (Italy); Bartali, R. [Fondazione Bruno Kessler, Via Sommarive 18, 38123 Povo (Trento) (Italy)

    2014-04-01

    Nanocrystalline diamond (NCD) coatings with thickness of about 3 μm were grown on silicon substrates at four deposition temperatures ranging from 653 to 884 °C in CH{sub 4}/H{sub 2}/Ar microwave plasmas. The morphology, structure, chemical composition and mechanical and surface properties were studied by means of Atomic Force Microscopy (AFM), X-Ray Diffraction (XRD), Raman spectroscopy, nanoindentation and Water Contact Angle (WCA) techniques. The different deposition temperatures used enabled to modulate the chemical, structural and mechanical NCD properties, in particular the grain size and the shape. The characterization measurements revealed a relatively smooth surface morphology with a variable grain size, which affected the incorporated hydrogen amount and the sp{sup 2} carbon content, and, as a consequence, the mechanical properties. Specifically, the hydrogen content decreased by increasing the grain size, whereas the sp{sup 2} carbon content increased. The highest values of hardness (121 ± 25 GPa) and elastic modulus (1036 ± 163 GPa) were achieved in NCD film grown at the lowest value of deposition temperature, which favored the formation of elongated nanocrystallites characterized by improved hydrophobic surface properties. - Highlights: • We produce the hardest NCD coating at the lowest deposition temperature. • We modify the deposition temperature to tailor the grain size and shape of the NCD coatings. • We assess the mechanical properties (hardness and elastic modulus) of superhard NCD coating on a soft silicon substrate.

  9. One-step surface selective modification of UV-curable hard coatings with photochemical metal organics

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Yoon Kwang; Park, Chang-Sun; Park, Hyung-Ho, E-mail: hhpark@yonsei.ac.kr

    2016-12-15

    Graphical abstract: This study demonstrates suitable for exceptional hybrid film under UV exposure. A small quantity of the dispersive photochemical precursor Sr 2-ethylhexanoate was mixed and the composition altered from the surface to the bottom, forming an organic layer and a densely concentrated SrO surface layer. The surface-selective SrO strongly enhanced the surface flatness and hardness of the UV-curable organic coating film. - Highlights: • Hybrid bi-layer coating was synthesized through one-pot UV exposure chemical route. • The influence of additive and different reactivity formed densely concentrated SrO surface layer. • Chemical composition and continuous interface between organic and inorganic were analyzed. • Surface flatness and mechanical property were improved by inorganic material. - Abstract: An organic–inorganic hybrid bi-layer film with a selective distribution of inorganic components was synthesized from a one-pot process of UV irradiation. A photochemical metal oxide precursor (Sr 2-ethylhexanoate) varying from 0 to 4 wt% was dispersed in UV-curable coating materials. Under UV exposure, the bi-layer started reacting simultaneously but at different rates due to differences in the two UV-condensable components’ reactivity. The effects of the dispersed inorganic component on the surface morphology and mechanical properties were investigated by atomic force microscopy and nanoindentation, respectively. The reaction process and rates were studied from linkage change using Fourier transform infrared spectroscopy at various UV exposure times (0–30 min). The elemental distribution and the interface on the coating layer were characterized by X-ray photoelectron spectroscopy from Ar etching, revealing continuous and gradual composition changes in depth. The results showed that a flattened and surface-selectively hardened SrO containing the coating film could be obtained by this simple process. Consequently, a small ratio of photochemical

  10. Automatic and robust deposition process control to grow hard ncTiC/a-C:H coatings using industrial magnetron sputtering devices and tribological analysis of the titanium-carbon coatings

    NARCIS (Netherlands)

    Žemlička, Radek; Jílek, Mojmír; Vogl, Petr; Pei, Yutao; Souček, Pavel; Buršíková, Vilma; Vašina, Petr

    nc-TiC/a-C:H coatings consist of TiC crystallites embedded in an amorphous hydrogenated carbon matrix. Depending mainly on the chemical composition, the properties of these coatings can be tailored from hard coatings, with hardness of greater than 35 GPa to tribological coatings, with coefficients

  11. Influence Of The Triple Spheroidization On Surface Hardness From Drilling Resistance Behavior Of Powder Coated Gray Cast Iron

    Directory of Open Access Journals (Sweden)

    Subhakij Khaonetr

    2015-08-01

    Full Text Available The objective of this study on the influence of the triple spheroidization on surface hardness from drilling resistance Dry drilling of powder coated gray cast iron using universal testing machine Compressive mode the surface hardness in powder coating areas normal hardness and Charpy impact resistance were considered. The spheroidizing temperatures were 300amp61616C 450amp61616C and 600amp61616C the spheroidizing time spanned the range of 6 hours and cooled down in the furnace to room temperature for 24 hours. The drilling resistance test the high-speed twist drill diameter of 3 mm the rotating speed of 1000 revmin and the crosshead speed of 5-25 mmmin were investigated. It was found that the surface hardness from drilling resistance normal hardness and Charpy impact resistance increased as the spheroidizing temperatures increased. The maximum surface hardness was found at the third spheroidization.

  12. Highly hard yet toughened bcc-W coating by doping unexpectedly low B content

    KAUST Repository

    Yang, Lina

    2017-08-18

    Either hardness or toughness has been the core interest in scientific exploration and technological pursuit for a long time. However, it is still a big challenge to enhance the hardness and toughness at the same time, since the improvement of one side is always at the expense of the other one. Here, we have succeeded in dealing with this pair of conflict based on tungsten (W) coating by doping boron (B) via magnetron co-sputtering. The results reveal that the introduction of low concentrations of B (6.3 at. %), in the doping regime, leads to the formation of W(B) supersaturated solid solution with refined grains. Meanwhile, the doping-induced higher compressive stress, higher H/E* and denser microstructure result in a surprising combination of improved hardness (2 × larger than pure W) and superior toughness (higher crack formation threshold compared to pure W). We believe this is an innovative sight to design new generation of transition-metal-based multifunctional coatings. Besides, our results are applicable for industrial application because it can be realized by simple manufacturing approaches, e.g. magnetron sputtering technology.

  13. Evaluation of using edible coating and ripening on Dangke, a traditional cheese of Indonesia

    Directory of Open Access Journals (Sweden)

    Malaka, R.

    2017-03-01

    Full Text Available Dangke is a traditional soft cheese from Enrekang, South Sulawesi Indonesia which is produced through heat denaturation at 85°C and enzymatic coagulation using papaya latex. The quality, microstructure and storage life of the cheese are affected by several factors such as denaturation temperature, enzyme concentration, moulding pressure, coating, and ripening. The objective of this study was to evaluated of using edible coating and ripening on Dangke cheese. The experiment was conducting using factorial design with five replications. The experimental variables were the type of edible coating used (agar, CMC and bee wax and the length of ripening (10, 20 and 30 days. Parameter was measured hardness, microstructure, and sensory evaluation. The overall result indicated that the use of edible coating can extend the shelf life, increase hardness, and more compact microstructure. Sensory evaluation also indicated that the cheese coated with film forming edible materials had had white color, more milk like smell (smelly milk, and smoother texture.

  14. Comparative Evaluation and Optimization of Film Coating ...

    African Journals Online (AJOL)

    Comparative Evaluation and Optimization of Film Coating Formulation Variables and Delayed Release Properties of Three Enteric Polymers on Diclofenac ... According to f2 test, the Wangit L30D-55® and Wangit L-100® coated tablets were similar to the two most commonly marketed products of diclofenac sodium 50 mg ...

  15. One-step surface selective modification of UV-curable hard coatings with photochemical metal organics

    Science.gov (United States)

    Lee, Yoon Kwang; Park, Chang-Sun; Park, Hyung-Ho

    2016-12-01

    An organic-inorganic hybrid bi-layer film with a selective distribution of inorganic components was synthesized from a one-pot process of UV irradiation. A photochemical metal oxide precursor (Sr 2-ethylhexanoate) varying from 0 to 4 wt% was dispersed in UV-curable coating materials. Under UV exposure, the bi-layer started reacting simultaneously but at different rates due to differences in the two UV-condensable components' reactivity. The effects of the dispersed inorganic component on the surface morphology and mechanical properties were investigated by atomic force microscopy and nanoindentation, respectively. The reaction process and rates were studied from linkage change using Fourier transform infrared spectroscopy at various UV exposure times (0-30 min). The elemental distribution and the interface on the coating layer were characterized by X-ray photoelectron spectroscopy from Ar etching, revealing continuous and gradual composition changes in depth. The results showed that a flattened and surface-selectively hardened SrO containing the coating film could be obtained by this simple process. Consequently, a small ratio of photochemical metal oxide reinforced the organic hard coating film's mechanical properties through the formation of an effective SrO top layer.

  16. Structure, hardness and adhesion in electroless nickel interlayer modified TiN coating on mild steel

    Energy Technology Data Exchange (ETDEWEB)

    Duh, J.G.; Doong, J.C. (Dept. of Materials Science and Engineering, National Tsing Hua Univ., Hsinchu (Taiwan))

    1993-03-10

    TiN films have been prepared by reactive rf magnetron sputtering on mild steel substrates, and electroless Ni-P plating has been introduced as an interlayer. A hypophospite-based bath has been used in this study to produce electroless Ni-P coatings. The electroless Ni-O deposits crystallize during rf sputtering due to the high sputtering temperature and a TiN/Ni[sub 3]/Fe coating assembly is formed. The pH value of the bath will affect the phosphorus content of the electroless Ni-P deposits, and the phosphorus content changes from 6.7 wt.% to 11 wt.% for pH 5.5 to pH 4.0. It is observed that the Ar/N[sub 2] flux ratio has a significant influence on the phase and structure of the deposited TiN film. The deposition rate increases as the nitrogen content is decreased. Pure TiN coatings are obtained for the Ar/N[sub 2] flux ratio range from 90/10 to 70/30. Unreacted Ti is found at an Ar/N[sub 2] ratio of 95/5 and 60/40 due to the incomplete reaction to form TiN. The employment of an electroless Ni-P deposit results in an increase in the surface microhardness and the adhesion strength. The surface hardness values were as high as 2266 HK[sub 1], close to the hardness of bulk TiN with the formation of an Ni[sub 3]P interlayer modified TiN coating. (orig.).

  17. Improvement of Wear Performance of Nano-Multilayer PVD Coatings under Dry Hard End Milling Conditions Based on Their Architectural Development

    Directory of Open Access Journals (Sweden)

    Shahereen Chowdhury

    2018-02-01

    Full Text Available The TiAlCrSiYN-based family of PVD (physical vapor deposition hard coatings was specially designed for extreme conditions involving the dry ultra-performance machining of hardened tool steels. However, there is a strong potential for further advances in the wear performance of the coatings through improvements in their architecture. A few different coating architectures (monolayer, multilayer, bi-multilayer, bi-multilayer with increased number of alternating nano-layers were studied in relation to cutting-tool life. Comprehensive characterization of the structure and properties of the coatings has been performed using XRD, SEM, TEM, micro-mechanical studies and tool-life evaluation. The wear performance was then related to the ability of the coating layer to exhibit minimal surface damage under operation, which is directly associated with the various micro-mechanical characteristics (such as hardness, elastic modulus and related characteristics; nano-impact; scratch test-based characteristics. The results presented exhibited that a substantial increase in tool life as well as improvement of the mechanical properties could be achieved through the architectural development of the coatings.

  18. Development of method for evaluating cell hardness and correlation between bacterial spore hardness and durability

    Science.gov (United States)

    2012-01-01

    Background Despite the availability of conventional devices for making single-cell manipulations, determining the hardness of a single cell remains difficult. Here, we consider the cell to be a linear elastic body and apply Young’s modulus (modulus of elasticity), which is defined as the ratio of the repulsive force (stress) in response to the applied strain. In this new method, a scanning probe microscope (SPM) is operated with a cantilever in the “contact-and-push” mode, and the cantilever is applied to the cell surface over a set distance (applied strain). Results We determined the hardness of the following bacterial cells: Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and five Bacillus spp. In log phase, these strains had a similar Young’s modulus, but Bacillus spp. spores were significantly harder than the corresponding vegetative cells. There was a positive, linear correlation between the hardness of bacterial spores and heat or ultraviolet (UV) resistance. Conclusions Using this technique, the hardness of a single vegetative bacterial cell or spore could be determined based on Young’s modulus. As an application of this technique, we demonstrated that the hardness of individual bacterial spores was directly proportional to heat and UV resistance, which are the conventional measures of physical durability. This technique allows the rapid and direct determination of spore durability and provides a valuable and innovative method for the evaluation of physical properties in the field of microbiology. PMID:22676476

  19. Coating defect evaluation based on stimulated thermography

    Science.gov (United States)

    Palumbo, Davide; Tamborrino, Rosanna; Galietti, Umberto

    2017-05-01

    Thermal Barrier Coatings are used to protect the materials from severe temperature and chemical environments. In particular, these materials are used in the engineering fields where high temperatures, corrosive environments and high mechanical stress are required. Defects present between substrate material and coating, as detachments may cause the break of coating and the consequent possibility to exposure the substrate material to the environment conditions. The capability to detect the defect zones with non-destructive techniques could allow the maintenance of coated components with great advantages in terms of costs and prediction of fatigue life. In this work, two different heat sources and two different thermographic techniques have been used to detect the adhesion defects among the base material and the coating. Moreover, an empirical thermographic method has been developed to evaluate the thickness of the thermal coating and to discriminate between an unevenness of the thickness and a defect zone. The study has been conducted on circular steel specimens with simulated adhesion defect and on specimens prepared with different thicknesses of thermal barrier coating.

  20. A hard X-ray telescope/concentrator design based on graded period multilayer coatings

    DEFF Research Database (Denmark)

    Christensen, Finn Erland; Joensen, K. D.; Gorenstein, P.

    1995-01-01

    that it is smaller than roughly 1 mm. The design can be realized with foils as thin (≤0.4 mm) as used for ASCA and SODART or with closed, slightly thicker (∼1.0 mm) mirror shells as used for JET-X and XMM. The effect of an increase of the inner radius is quantified on the effective area for multilayered mirrors up...... of the telescope configuration provided that mirrors can be coated to an inner radius of 3 cm. Specifically we find that a change of focal length from 5 to 12 m affects the effective area by less than 10%. In addition the result is insensitive to the thickness of the individual mirror shell provided....../cm2/s/keV which demonstrates the great potential of this hard X-ray imaging telescope in the energy range up to 100 keV....

  1. Tensile and Hardness Property Evaluation of Kaolin- Sisal Fibre ...

    African Journals Online (AJOL)

    In this work, the tensile and hardness properties of Kaolin- sisal fibre- epoxy composite were evaluated using standard methods. Epoxy type 3354A with its hardener was mixed in the ratio 2:1. Calcined kaolin particle with average size of 35µm and 3-4mm sisal fibre were added to the epoxy matrix during the composite ...

  2. Stability and drug dissolution evaluation of Qingkailing soft/hard ...

    African Journals Online (AJOL)

    Stability and drug dissolution evaluation of Qingkailing soft/hard capsules based on multi-component quantification and fingerprint pattern statistical analysis. Ruyu Sun, Huihui Teng, Xiaonan Chen, Shuang Guo, Shan Jia, Mengcheng Zheng, Yang Lu, Jie Bai, Pengyue Li, Shouying Du ...

  3. Annual Report - Compatibility of ZDDP and ionic liquid anti-wear additives with hard coatings for engine lubrications

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Jun [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Zhou, Yan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Leonard, Donovan N [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Meyer, III, Harry M [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Luo, Huimin [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-03-01

    The objectives for this considerations described here are to; investigate the compatibility of engine lubricant antiwear (AW) additives, specifically conventional zinc dialkyldithiophosphate (ZDDP) and newly developed ionic liquids (ILs), with selected commercial hard coatings, and provide fundamental understanding to guide future development of engine lubricants.

  4. Influence of hardness and roughness on the tribological performance of TiC/a-C nanocomposite coatings

    NARCIS (Netherlands)

    Shaha, K. P.; Pei, Y. T.; Martinez Martinez, D.; De Hosson, J. Th. M.

    2010-01-01

    The influence of the hardness of counterface materials on the tribological behavior of TiC/a-C nanocomposite coatings exhibiting various surface roughness was examined by using a ball on a disc configuration in humid air. While sliding against 100Cr6 steel balls, the steady state coefficient of

  5. Comparative study between the electrochemical behavior of TiN, TiCxNy and CrN hard coatings by using microscopy and electrochemical techniques

    Directory of Open Access Journals (Sweden)

    L.F. Senna

    2001-01-01

    Full Text Available Hard thin TiN, TiCxNy and CrN films deposited by Physical Vapor Deposition (PVD techniques onto steel substrates were immersed in an aggressive environment and evaluated by Atomic Force Microscopy (AFM and Electrochemical Impedance Spectroscopy (EIS. The mechanical and electrochemical behavior, as well as the microstructure of TiCxNy depended directly on the contents of carbon and nitrogen in the coating. The best results were obtained with stoichiometric coatings that are presented in this work. Although a small amount of pinholes could be observed, the electrochemical performance of TiN film was poorer than the stoichiometric TiCxNy coating. However, the CrN films showed the highest initial and residual corrosion resistance values, probably due to their dense structure.

  6. Evaluation of hardness and wear resistance of interim restorative materials.

    Science.gov (United States)

    Savabi, Omid; Nejatidanesh, Farahnaz; Fathi, Mohamad Hossein; Navabi, Amir Arsalan; Savabi, Ghazal

    2013-03-01

    The interim restorative materials should have certain mechanical properties to withstand in oral cavity. The aim of this study was to evaluate the hardness and wear resistance of interim restorative materials. Fifteen identical rectangular shape specimens with dimensions of 2 mm × 10 mm × 30 mm were made from 7 interim materials (TempSpan, Protemp 3 Garant, Revotek, Unifast LC, Tempron, Duralay, and Acropars). The Vickers hardness and abrasive wear of specimens were tested in dry conditions and after 1 week storage in artificial saliva. The depth of wear was measured using surface roughness inspection device. Data were subjected to Kruskal-Wallis and Mann-Whitney tests. The Pearson correlation coefficient was used to determine the relationship between hardness and wear (α =0.05). TempSpan had the highest hardness. The wear resistance of TempSpan (in dry condition) and Revotek (after conditioning in artificial saliva) was significantly higher (P materials (P = 0.281, r = -0.31). Hardness and wear resistance of interim resins are material related rather than category specified.

  7. Phenolics in the seed coat of wild soybean (Glycine soja) and their significance for seed hardness and seed germination.

    Science.gov (United States)

    Zhou, San; Sekizaki, Haruo; Yang, Zhihong; Sawa, Satoko; Pan, Jun

    2010-10-27

    Hardseededness in annual wild soybean (Glycine soja Sieb. Et Zucc.) is a valuable trait that affects the germination, viability, and quality of stored seeds. Two G. soja ecotypes native to Shandong Province of China have been used to identify the phenolics in the seed coat that correlate with the seed hardness and seed germination. Three major phenolics from the seed coat were isolated and identified as epicatechin, cyanidin 3-O-glucoside, and delphinidin 3-O-glucoside. Of the three phenolics, only the change of epicatechin exhibited a significant positive correlation with the change of hard seed percentages both under different water conditions during seed development and under different gas conditions during seed storage. Epicatechin also reveals a hormesis-like effect on the seed germination of G. soja. Epicatechin is suggested to be functionally related to coat-imposed hardseededness in G. soja.

  8. Comparative of the Tribological Performance of Hydraulic Cylinders Coated by the Process of Thermal Spray HVOF and Hard Chrome Plating

    Directory of Open Access Journals (Sweden)

    R.M. Castro

    2014-03-01

    Full Text Available Due to the necessity of obtaining a surface that is resistant to wear and oxidation, hydraulic cylinders are typically coated with hard chrome through the process of electroplating process. However, this type of coating shows an increase of the area to support sealing elements, which interferes directly in the lubrication of the rod, causing damage to the seal components and bringing oil leakage. Another disadvantage in using the electroplated hard chromium process is the presence of high level hexavalent chromium Cr+6 which is not only carcinogenic, but also extremely contaminating to the environment. Currently, the alternative process of high-speed thermal spraying (HVOF - High Velocity Oxy-Fuel, uses composite materials (metal-ceramic possessing low wear rates. Research has shown that some mechanical properties are changed positively with the thermal spray process in industrial applications. It is evident that a coating based on WC has upper characteristics as: wear resistance, low friction coefficient, with respect to hard chrome coatings. These characteristics were analyzed by optical microscopy, roughness measurements and wear test.

  9. Performance evaluation of seal coat materials and designs.

    Science.gov (United States)

    2011-01-01

    "This project presents an evaluation of seal coat materials and design method. The primary objectives of this research are 1) to evaluate seal coat performance : from various combinations of aggregates and emulsions in terms of aggregate loss; 2) to ...

  10. Fabrication of nitrogen-containing diamond-like carbon film by filtered arc deposition as conductive hard-coating film

    Science.gov (United States)

    Iijima, Yushi; Harigai, Toru; Isono, Ryo; Imai, Takahiro; Suda, Yoshiyuki; Takikawa, Hirofumi; Kamiya, Masao; Taki, Makoto; Hasegawa, Yushi; Tsuji, Nobuhiro; Kaneko, Satoru; Kunitsugu, Shinsuke; Habuchi, Hitoe; Kiyohara, Shuji; Ito, Mikio; Yick, Sam; Bendavid, Avi; Martin, Phil

    2018-01-01

    Diamond-like carbon (DLC) films, which are amorphous carbon films, have been used as hard-coating films for protecting the surface of mechanical parts. Nitrogen-containing DLC (N-DLC) films are expected as conductive hard-coating materials. N-DLC films are expected in applications such as protective films for contact pins, which are used in the electrical check process of integrated circuit chips. In this study, N-DLC films are prepared using the T-shaped filtered arc deposition (T-FAD) method, and film properties are investigated. Film hardness and film density decreased when the N content increased in the films because the number of graphite structures in the DLC film increased as the N content increased. These trends are similar to the results of a previous study. The electrical resistivity of N-DLC films changed from 0.26 to 8.8 Ω cm with a change in the nanoindentation hardness from 17 to 27 GPa. The N-DLC films fabricated by the T-FAD method showed high mechanical hardness and low electrical resistivity.

  11. Hard coating performance enhancement by using [Ti/TiN]{sub n}, [Zr/ZrN]{sub n} and [TiN/ZrN]{sub n} multilayer system

    Energy Technology Data Exchange (ETDEWEB)

    Caicedo, J.C., E-mail: jcesarca@calima.univalle.edu.co [Department of Physics, Thin Film Group, Universidad del Valle, Cali (Colombia); Amaya, C. [Department of Physics, Thin Film Group, Universidad del Valle, Cali (Colombia); Hard Coatings Laboratory, CDT-ASTIN SENA, Cali (Colombia); Yate, L.; Nos, O. [Department de Fisica Aplicada i Optica, Universitat de Barcelona, Catalunya (Spain); Gomez, M.E. [Department of Physics, Thin Film Group, Universidad del Valle, Cali (Colombia); Prieto, P. [Department of Physics, Excellence Center for Novel Materials, Universidad del Valle, Cali (Colombia)

    2010-07-25

    In order to increase the performance of hard coatings for industrial application, Ti/TiN, Zr/ZrN and TiN/ZrN multilayers were deposited onto Si(1 0 0) and AISI 5160 steel substrates via r.f. (13.56 MHz) multi-target magnetron sputtering technique. The crystallography structures of Ti/TiN, Zr/ZrN and TiN/ZrN multilayers were evaluated via X-ray diffraction analysis (XRD). The composition, chemical-depth distribution and cross-sectional morphology of the films were characterized by EDX, SIMS, and SEM. The enhancement of mechanical properties and adherence strength behavior were determined via nanoindentation and scratch test, respectively. From these results, it was found that hardness and critical load of all multilayer films depends on the bilayer period ({Lambda}) and bilayer number (n). Moreover, the TiN/ZrN multilayer films exhibit the highest hardness (30 {+-} 1 GPa) and critical load (60 {+-} 1 N) in relation to Ti/TiN and Zr/ZrN multilayers. The different mechanical performances and mechanisms in the multilayers group were observed and discussed in this paper, suggesting the possibility to use AISI 5160 steel coated with multilayers as cutting tools.

  12. Effect of coating Straumann Bone Ceramic with Emdogain on mesenchymal stromal cell hard tissue formation.

    Science.gov (United States)

    Mrozik, Krzysztof Marek; Gronthos, Stan; Menicanin, Danijela; Marino, Victor; Bartold, P Mark

    2012-06-01

    Periodontal tissue engineering requires a suitable biocompatible scaffold, cells with regenerative capacity, and instructional molecules. In this study, we investigated the capacity of Straumann Bone Ceramic coated with Straumann Emdogain, a clinical preparation of enamel matrix protein (EMP), to aid in hard tissue formation by post-natal mesenchymal stromal cells (MSCs) including bone marrow stromal cells (BMSCs) and periodontal ligament fibroblasts (PDLFs). MSCs were isolated and ex vivo-expanded from human bone marrow and periodontal ligament and, in culture, allowed to attach to Bone Ceramic in the presence or absence of Emdogain. Gene expression of bone-related proteins was investigated by real time RT-PCR for 72 h, and ectopic bone formation was assessed histologically in subcutaneous implants of Bone Ceramic containing MSCs with or without Emdogain in NOD/SCID mice. Alkaline phosphatase activity was also assessed in vitro, in the presence or absence of Emdogain. Collagen-I mRNA was up-regulated in both MSC populations over the 72-h time course with Emdogain. Expression of BMP-2 and the osteogenic transcription factor Cbfa-1 showed early stimulation in both MSC types after 24 h. In contrast, expression of BMP-4 was consistently down-regulated in both MSC types with Emdogain. Up-regulation of osteopontin and periostin mRNA was restricted to BMSCs, while higher levels of bone sialoprotein-II were observed in PDLFs with Emdogain. Furthermore, alkaline phosphatase activity levels were reduced in both BMSCs and PDLFs in the presence of Emdogain. Very little evidence was found for ectopic bone formation following subcutaneous implantation of MSCs with Emdogain-coated or -uncoated Bone Ceramic in NOD/SCID mice. The early up-regulation of several important bone-related genes suggests that Emdogain may have a significant stimulatory effect in the commitment of mesenchymal cells to osteogenic differentiation in vitro. While Emdogain inhibited AP activity and appeared

  13. Hardness Evaluation of Composite Resins Cured with QTH and LED

    Directory of Open Access Journals (Sweden)

    Behnaz Esmaeili

    2014-03-01

    Full Text Available Background and aims. Today light cured composites are widely used. Physical and mechanical properties of composites are related to the degree of conversion. Light curing unit (LCU is an important factor for composite polymerization. Aim of this study is evaluation of composite resins hardness using halogen and LED light curing units. Materials and methods. In this study, 30 samples of Filtek Z250 and C-Fill composite resins were provided. Samples were light cured with Ultralume2, Valo and Astralis7. Vickers hardness number (VHN was measured in 0, 1, 2 mm depth. Statistical analysis used: Data were analysed by SPSS software and compared with each other by T-test, one-way and twoway ANOVA and Post-hoc Tukey test. Results. In Filtek Z250, at top surface, VHN of Ultralume2 was higher than VHN of Valo (P = 0.02 and Astralis7 (P = 0.04, but in depth of 1, 2 mm, VHN of Ultralume2 and Astralis7 were almost the same and both LCUs were more than Valo which the difference between Ultralume2 and Valo was significant in depth of 1mm (0.05 and 2mm (0.02. In C-Fill composite, at top surface, Astralis7 showed higher VHN, but in depth of 2 mm, performance of all devices were rather similar. Conclusion. In Z250, which contains camphorquinone initiator, light cure LED Ultra-lume2 with narrow wavelength showed higher hardness number than Valo. In C-fill, in top surface, Astralis7 with more exposure time, resulted higher VHN. But In depth of 2 mm, various light curing devices had rather similar hardness number.

  14. Very Hard Corrosion-Resistant Roll-Bonded Cr Coating on Mild Steel in Presence of Graphite

    Science.gov (United States)

    Kumar, Pankaj; Khara, S.; Shekhar, S.; Mondal, K.

    2017-11-01

    Abstract The present work discusses the development of very hard Cr and Cr-carbide coating by roll bonding of Cr powder on a mild steel followed by annealing at 800, 1000, 1100 and 1200 °C with and without the presence of graphite powder packing in argon environment. In addition, the effect of a roll skin pass of 5% prior to the application of coating was studied. The presence of graphite allows diffusion of both carbon and Cr in the mild steel substrate, leading to the formation of Cr-carbide on the outer surface, making the surface very hard (VHN 1800). Depending on the annealing temperature and processing condition, diffusion layer thickness of Cr is found to be in the range of 10-250 μm with Cr content of 12.5-15 wt.% across the diffusion layer. Excellent stable passivity of the coated surface is observed in 0.2 N H2SO4, which is comparable to a highly passivating 304 stainless steel, and very low corrosion rate of the coating is observed as compared to the substrate mild steel.

  15. Tool life of the edges coated with the c-BN+h-BN coatings with different structures during hard machinable steel machining

    Directory of Open Access Journals (Sweden)

    Kupczyk, M.

    2005-12-01

    Full Text Available In the presented paper the experimental results concerning the functional quality (durability during steel machining of thin, superhard coatings produced on the cutting edges are described. Differences among mentioned properties of coatings mainly result from a coating structure. But the structure of coatings results from deposition parameters Superhard boron nitride coatings were deposited on insert cutting edges made of cemented carbides by the pulse-plasma method applying different values of the discharge voltage. The comparative investigations of mentioned coatings have been concerned of tool life of edges during hard machinable material machining (nitriding steel hardened in oil. In these investigations for the purpose of additional increase of coatings adhesion to substrates an interfacial layers were applied.

    En este trabajo se describen los resultados experimentales referentes a la calidad funcional (durabilidad durante el mecanizado del acero de recubrimientos delgados, de elevada dureza del filo de corte. Las diferencias en las propiedades de los recubrimientos se deben, principalmente, a la estructura del recubrimiento. No obstante, la estructura del recubrimiento está relacionada con los parámetros de la deposición. Recubrimientos de nitruro de boro de elevada dureza se depositaron sobre filos de corte insertados, fabricados con carburos cementados mediante el método de pulsos de plasma aplicando diferentes valores de voltaje de descarga. Las investigaciones comparativas de los mencionados recubrimientos han relacionado la vida del filo de la herramienta durante el mecanizado del material (acero nitrurado endurecido en aceite. En estas investigaciones se aplicaron capas interfaciales para aumentar la adherencia del recubrimiento.

  16. Determination of the fatigue behaviour of thin hard coatings using the impact test and a FEM simulation

    Energy Technology Data Exchange (ETDEWEB)

    Bouzakis, K.D. [Aristoteles Univ., Thessaloniki (Greece). Dept. of Mech. Eng.; Vidakis, N. [Aristoteles Univ., Thessaloniki (Greece). Dept. of Mech. Eng.; Leyendecker, T. [CemeCon, 52068 Aachen (Germany); Lemmer, O. [CemeCon, 52068 Aachen (Germany); Fuss, H.G. [CemeCon, 52068 Aachen (Germany); Erkens, G. [CemeCon, 52068 Aachen (Germany)

    1996-12-15

    The impact test, in combination with a finite element method (FEM) simulation, is used to determine stress values that characterise the fatigue behaviour of thin hard coatings, such as TiAlN, TiAlCN, CrN, MoN, etc. The successive impacts of a cemented carbide ball onto a coated probe induce high contact loads, which can vary in amplitude and cause plastic deformation in the substrate. In the present paper FEM calculations are used in order to determine the critical stress values, which lead to coating fatigue failure. The parametric FEM simulation developed considers elastic behaviour for the coating and elastic plastic behaviour for the substrate. The results of the FEM calculations are correlated to experimental data, as well as to SEM observations of the imprints and to microspectrum analyses within the contact region. Herewith, critical values for various stress components, which are responsible for distinctive fatigue failure modes of the coating-substrate compounds can be obtained. (orig.)

  17. Fluor-hydroxyapatite sol-gel coating on titanium substrate for hard tissue implants.

    Science.gov (United States)

    Kim, Hae-Won; Kim, Hyoun-Ee; Knowles, Jonathan C

    2004-08-01

    Hydroxyapatite (HA) and fluor-hydroxyapatite (FHA) films were deposited on a titanium substrate using a sol-gel technique. Different concentrations of F- were incorporated into the apatite structure during the sol preparation. Typical apatite structures were obtained for all coatings after dipping and subsequent heat treatment at 500 degrees C. The films obtained were uniform and dense, with a thickness of approximately 5 microm. The dissolution rate of the coating layer decreased with increasing F- incorporation within the apatite structure, which demonstrates the possibility of tailoring the solubility by a functional gradient coating of HA and FHA. The cell proliferation rate on the coating layer decreased slightly with increasing F- incorporation. The alkaline phosphatase (ALP) activity of the cells on all the HA and FHA coated samples showed much higher expression levels compared to pure Ti. This confirmed the improved activity of cell functions on the substrates with the sol-gel coating treatment.

  18. WC-Co COATINGS AND SINTERS MODIFIED WITH NANO-SIZED TiC MICROSTRUCTURE – QUANTITATIVE EVALUATION

    Directory of Open Access Journals (Sweden)

    Hanna Myalska

    2017-03-01

    Full Text Available The different concepts of WC-Co thermally sprayed coatings improvement may be considered and the application of nanoparticles, as the mechanical strengthening addition, is one of them. Nanostructured WC-Co coatings are characterized by higher hardness than the coatings formed from micrometric WC grains; whereas coatings with bimodal distribution of particles reveal greater wear resistance than the coatings obtained exclusively from nano-sized powders. Mixed effect of the matrix reinforcement by nanoparticles and strong fix of the micron-sized WC grains was proposed as a possible reason for enhanced wear resistance of bimodal coatings. In order to obtain a bimodal distribution of particles in the material standard WC-Co (83-17 powder was mixed with nanometric TiC powder (40-100 nm. The amount of TiC in powder mixtures was in the range from 1 to 7 wt.%. The mixtures were deposited on steel substrate using HVAF method and also hot pressed in vacuum. The microstructure of obtained coatings and sinters was quantitatively evaluated. Sinters revealed more homogenous distribution of the nano-sized TiC particles than the coatings. The addition of nano-sized TiC in the case of coatings has led to the decrease of its porosity. The agglomeration of nano-sized TiC particles in the coatings results in the decrease of material’s hardness.

  19. Characterization and analyses on micro-hardness, residual stress and microstructure in laser cladding coating of 316L stainless steel subjected to massive LSP treatment

    Energy Technology Data Exchange (ETDEWEB)

    Luo, K.Y.; Jing, X.; Sheng, J. [School of Mechanical Engineering, Jiangsu University, Zhenjiang, 212013 (China); Sun, G.F. [School of Mechanical Engineering, Southeast University, Nanjing, 211189 (China); Yan, Z. [School of Mechanical Engineering, Jiangsu University, Zhenjiang, 212013 (China); Lu, J.Z., E-mail: jzlu@ujs.edu.cn [School of Mechanical Engineering, Jiangsu University, Zhenjiang, 212013 (China)

    2016-07-15

    The effects of massive laser shock peening (LSP) treatment on micro-hardness, residual stress and microstructure in four different zones of laser cladding coating was investigated. Furthermore, micro-hardness curves and residual stress distributions with and without massive LSP treatment were presented and compared, and typical microstructure in different zones of both coatings were characterized by transmission electron microscope (TEM) and cross-sectional optical microscope (OM) observations. Results and analyses showed that massive LSP treatment had an important influence on micro-hardness and residual stress of the cladding coating. Special attempt was made to the effects of massive LSP treatment on microstructure in three zones of the cladding coating. In addition, the underlying mechanism of massive LSP treatment on microstructure and mechanical properties of the cladding coating was revealed clearly. - Highlights: • Micro-hardness and residual stress curves of both coatings were presented and compared. • Typical microstructure in different zones of both coatings were characterized and analyzed. • LSP causes increased micro-activities, and induces plastic deformation layer in three zones. • Underlying mechanism of LSP on mechanical properties of cladding coating was revealed.

  20. Microstructure, mechanical properties and tribological performance of TiSiN-WS2 hard-lubricant coatings

    Science.gov (United States)

    Li, Shipeng; Deng, Jianxin; Yan, Guangyuan; Zhang, Kedong; Zhang, Guodong

    2014-08-01

    TiSiN-WS2 hard-lubricant coatings were deposited on WC/TiC/Co cemented carbides by arc ion plating and middle-frequency magnetron sputtering. The microstructure, mechanical properties and tribological performance were examined. Results showed that WS2 layer had (0 0 2) and (1 0 1) multi-orientation structure and TiN grains of TiSiN layer became bigger due to the annealing effect in deposition of WS2 layer. As the thickness of WS2 layer increased, hardness of TiSiN-WS2 coatings decreased largely while the adhesive strength increased, which is mainly beneficial from the release of residual stress of TiSiN layer in deposition process of WS2 layer and the low tensile stress caused by the lubricant effect of WS2 in scratch test. The deposition of WS2 layer on top of TiSiN layer significantly improved coatings’ tribological performance with lower friction coefficient, less adhesive materials and smaller wear rate of steel ball. Even after WS2 layer was worn out, the friction coefficient was still lower than TiSiN coating, which is attributed to that WS2 remaining in wear track still worked.

  1. Evaluation of the adhesion strength of diamond films brazed on K-10 type hard metal

    Directory of Open Access Journals (Sweden)

    Sérgio Ivan dos Santos

    2004-06-01

    Full Text Available The coating of cutting tools with diamond films considerably increases the tool performance due to the combination of the unique tribological properties of diamond with the bulk properties of the substrate (toughness. The tool performance, however, is strongly related to the adhesion strength between the film and the substrate. In this work our main goal was to propose and to test a procedure, based on a tensile strength test, to evaluate the adhesion strength of a diamond wafer brazed on a hard metal substrate, taking into account the effect of the brazing temperature and time. The temperature range studied was from 800 to 980 °C and the brazing time ranged from 3 to 40 min. The obtained results could be used to optimize the costs and time required to the production of high performance cutting tools with brazed diamond wafers.

  2. Development of Multilayer Coatings for Hard X-Ray Optics at NASA Marshall Space Flight Center

    Science.gov (United States)

    Gurgew, Danielle N.; Broadway, David M.; Ramsey, Brian; Gregory, Don

    2017-01-01

    Broadband X-ray multilayer coatings are under development at NASA MSFC for use on future astronomical X-ray telescopes. Multilayer coatings deposited onto the reflecting surfaces of X-ray optics can provide a large bandpass enabling observations of higher energy astrophysical objects and phenomena.

  3. A new algorithm for the evaluation of the global hardness of polyatomic molecules

    Science.gov (United States)

    Islam, Nazmul; Ghosh, Dulal Chandra

    2011-03-01

    Relying upon the commonality of the basic philosophy of the origin and development of electronegativity and hardness, we have attempted to explore whether a hardness equalization principle can be conceived for polyatomic molecules analogous to the electronegativity equalization principle. Starting from the new radial-dependent electrostatic definition of hardness of atoms suggested by the present authors and assuming that the hardness equalization principle is operative and valid, we have derived a formula for evaluating the hardness of polyatomic molecule, ? , where n is the number of ligands, ri is the atomic radius of the ith atom and C is a constant. The formula has been used to calculate the hardness values of 380 polyatomic molecules with widely divergent physico-chemical properties. The computed hardness data of a set of representative molecules are in good agreement with the corresponding hardness data evaluated quantum mechanically. The hardness data of the present work are found to be quite efficacious in explaining the known reaction surfaces of some well-known hard-soft acid-base exchange reactions in the real world. However, the hardness data evaluated through the ansatz and operational and approximate formula of Parr and Pearson poorly correlate the same reaction surface. This study reveals that the new definition of hardness and the assumed model of hardness equalization are scientifically acceptable valid propositions.

  4. Effect of substrate rotation on structure, hardness and adhesion of magnetron sputtered TiB{sub 2} coating on high speed steel

    Energy Technology Data Exchange (ETDEWEB)

    Panich, N. [School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, 639798 Singapore (Singapore)]. E-mail: panich@pmail.ntu.edu.sg; Sun, Y. [School of Materials Science and Engineering, Nanyang Technological University, Nanyang Avenue, 639798 Singapore (Singapore)

    2006-04-03

    Titanium diboride (TiB{sub 2}) coatings have been deposited on stationary and rotating high speed steel substrates by magnetron sputtering of a TiB{sub 2} target. The structure and hardness of the coatings and the coating-substrate adhesion have been investigated by X-ray diffraction, field emission scanning electron microscopy, nanoindentation and microscratch tests. The results show that substrate rotation has a significant effect on these structural and properties features. It was found that, with substrate rotation, the TiB{sub 2} coating exhibits a columnar structure with random orientation and relatively low hardness and coating-substrate adhesion. On the other hand, without substrate rotation, the TiB{sub 2} coating shows a strong (001) texture with dense, equiaxed grain structure. The hardness and coating-substrate adhesion of the coatings deposited on stationary substrates are much higher than those deposited on rotating substrates. The observed phenomena are discussed in terms of the energy of the sputtered flux, which varies with the substrate-target distance during deposition.

  5. A review of producing hard coatings by means of duplex treatments using an electroplated coating–thermochemical treatment combination

    Directory of Open Access Journals (Sweden)

    Héctor Cifuentes Aya

    2011-12-01

    Full Text Available Duplex treatments have been developed to overcome the disadvantages presented by simple treatments to surfaces of different materials and have, in a combined and complementary way, the properties that each of these methods supplies individually. The difference between thermal expansion coefficients for Fe and Cr in hard chrome plating leads to crack formation in the deposited coat, through which corrosive agents migrate and reduce the system’s integrity.Direct deposition by physical vapour deposition (PVD, used for obtaining chromium nitride films on steel substrates, is limited by high production costs, the low thickness obtained and low resistance to corrosion due to the presence of micro pores. Some studies have combined an electroplated chromium with thermochemical treatments made in a controlled atmosphere or vacuum furnaces or by plasma. This kind of duplex treatment allows compounds such as CrxN, CrxCyN and CrxCy to be obtained from chemical and micro structural transformation of chromium with nitrogen and/or carbon, the sealing of cracks in the coating and increasing the magnitude of properties like hardness and density, improving wear and abrasion and corrosion resistance.

  6. Interfacial microstructures and hardness distributions of vacuum plasma spraying W-coated ODS ferritic steels for fusion plasma facing applications

    Energy Technology Data Exchange (ETDEWEB)

    Noh, Sanghoon, E-mail: shnoh@kaeri.re.kr [Nuclear Materials Division, Korea Atomic Energy Research Institute, Yuseong-gu, Daejeon (Korea, Republic of); Kasada, Ryuta; Kimura, Akihiko [Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto (Japan); Nagasaka, Takuya [National Institute for Fusion Science, Toki, Gifu (Japan); Sokolov, Mikhail A. [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Kim, Tae Kyu [Nuclear Materials Division, Korea Atomic Energy Research Institute, Yuseong-gu, Daejeon (Korea, Republic of)

    2014-04-15

    In the present study, interfacial microstructures and hardness distributions of W-coated ODS steels as plasma facing structural materials were investigated. A vacuum plasma spraying (VPS) technique was employed to fabricate a W layer on the surface of the ODS ferritic steel substrates. The microstructural observations revealed that the VPS-W has very fine grains aligned toward the spraying direction, and a favorable interface between W and ODS ferritic steels by a mechanical inter-locking without an intermetallic layer. However, crack-type defects were found in VPS-W. Because a brittle inter-diffused layer does not exist at the joint interface, the hardness was gradually distributed in the joint region. After neutron irradiation, irradiation hardening significantly occurred in the VPS-W. However, the hardening of VPS-W was less than that of bulk W irradiated at 773 K. Thus, the VPS is considered to be one of the promising ways to join dissimilar materials between W and ODS steels, which can avoid the formation of an interfacial intermetallic layer and create favorable irradiation hardening resistance on the W coated layer.

  7. Hard α-Al2O3 Film Coating on Industrial Roller Using Aerosol Deposition Method

    Science.gov (United States)

    Seto, Naoki; Endo, Kazuteru; Sakamoto, Nobuo; Hirose, Shingo; Akedo, Jun

    2014-12-01

    It is well known that α-Al2O3 forms very hard, highly insulating, smooth films. There is demand for the use of such films instead of conventional hard, smooth films; For example, industrial rollers such as calendering rollers etc. are always required to have a harder and smoother surface than conventional rollers. Therefore, this work investigated the specification of α-Al2O3 films, e.g., their wear resistance and chemical stability, using various tests. This paper also discusses whether α-Al2O3 film can take the place of Cr plating film as a hard, smooth film by comparing their wear resistance and chemical stability.

  8. Precise femtosecond laser crater fabrication in hard nanolayered AlTiN/TiN coating on steel substrate

    Science.gov (United States)

    Gaković, B.; Petrović, S.; Albu, C.; Zamfirescu, M.; Panjan, P.; Milovanović, D.; Popescu-Pelin, G.; Mihailescu, I. N.

    2017-03-01

    Processing of AlTiN/TiN multilayered hard coatings by femtosecond (fs) laser pulses has been investigated. Irradiation was performed in air with linearly polarized laser radiation with pulses of 200 fs duration at 775 nm wavelength. Single or 1000 subsequent laser pulses were directed at normal incidence towards target surface. Laser energy per pulse was adjusted from 0.5 to 50 μJ and corresponding fluence was 0.17-17.5 J cm-2. The as deposited and laser-ablated samples were characterized by optical confocal microscopy, optical profilometry and scanning and transmition electron microscopy. In case of the AlTiN/TiN coating, a single-pulse damage threshold of 0.41 J cm-2 was estimated. Well defined holes/craters with diameters from 7 to 35 μm, up to 40 μm depth were drilled, depending on laser pulse energy and number, after 1000 laser pulses. For small energy/fluence, laser induced periodical surface structures were observed. A model is discussed which can account for these features by the accumulation effect during multi-pulse irradiation. The forming craters can prove useful for fabrication of micron solid state lubricant reservoirs in the protective coating-steel system.

  9. Hard Cr–Al–Si–B–(N) coatings deposited by reactive and non-reactive magnetron sputtering of CrAlSiB target

    Energy Technology Data Exchange (ETDEWEB)

    Kiryukhantsev-Korneev, Ph.V., E-mail: kiruhancev-korneev@yandex.ru [National University of Science and Technology “MISIS”, Leninsky pr., 4, Moscow 119049 (Russian Federation); Pierson, J.F. [Institut Jean Lamour - Ecole des Mines, Parc de Saurupt, CS 14 234, F-54042 Nancy (France); Kuptsov, K.A.; Shtansky, D.V. [National University of Science and Technology “MISIS”, Leninsky pr., 4, Moscow 119049 (Russian Federation)

    2014-09-30

    Highlights: • Cr–Al–Si–B–N coatings with amorphous structure. • Coatings demonstrate hardness in range of 18–30 GPa. • Coatings exhibit friction coefficient ∼0.4. • Coatings show a very high oxidation resistance up to 1300 °C. • Coatings withstand cyclic loads up to 1000 N for 10{sup 5} cycles without fracture. - Abstract: Relationships between chemical composition, mechanical and tribological properties, fracture resistance, thermal stability and oxidation resistance of the magnetron sputtered Cr–Al–Si–B–(N) coatings were determined using X-ray diffraction, scanning and transmission electron microscopy, glow discharge optical emission spectroscopy, nanoindentation, as well as pin-on-disk, scratch and impact tests. The coatings deposited in Ar showed high friction coefficient and wear rate of 0.8 and 46.0 × 10{sup −6} mm{sup 3}/N m during tribological tests compared with 0.4 and 2.0–2.1 × 10{sup −6} mm{sup 3}/N m of reactively deposited coatings. During impact tests, N-free coatings showed the smallest impact wear of 1.34 × 10{sup 5} μm{sup 3}, but, in contrast to the N-containing coatings, demonstrated fracture even at a load of 800 N. It was explained by the fact that the N-free coating, having high hardness of 30 GPa, yet was very brittle. Structural changes and oxidation mechanism of the Cr–Al–Si–B–(N) coatings during annealing in air at temperatures up to 1300 °C were also studied in detail. It was revealed that the coating deposited in Ar showed the best oxidation resistance up to 1300 °C.

  10. The influence of the phosphorous content and heat treatment on the nano-micro-structure, thickness and micro-hardness of electroless Ni-P coatings on steel

    Science.gov (United States)

    Czagány, M.; Baumli, P.; Kaptay, G.

    2017-11-01

    Electroless Ni-P coatings were obtained on steel substrates using different bath compositions, which lead to different phosphorous contents of the coatings. In this paper the effect of the P-content in the Ni-P coatings was experimentally studied on the thickness of the coating, on its nano-micro-structure and on its micro-hardness. The as-received samples were nano-crystalline (mostly amorphous according to XRD) and their micro-hardness was found to decrease with increasing the P-content. Upon annealing at 400 °C a new Ni3P phase was formed and the nano-cystalline Ni-rich grains coarsened to micro-grains. In this annealed state the micro-hardness was found to increase with increasing the P-content. A complex model was built to explain the experimental results. It was supposed that the as-received Ni-P coating contains almost pure Ni nano-grains surrounded by segregated P atoms; as the grain grows, its surface is covered more and more by the P atoms. When the grain is fully covered by the P atoms, further grain growth is inhibited and the coating can grow further only due to nucleation of a new grain. Thus, the size of the grains was found inversely proportional to the P-content of the Ni-P alloy. The need for a larger number of nucleation events with decreasing grain size explains why the coating has a smaller thickness for smaller grain size, i.e. higher P-content. The inverse Hall-Petch rule was found for the grain size dependence of micro-hardness of the as deposited samples due to the grain boundary sliding of relatively hard Ni-rich nano-crystals along the soft P atoms (higher P-content lead to lower micro-hardness through smaller grain size). After annealing the micro-hardness was found to increase with the volumetric phase fraction of the harder Ni3P phase within a relatively soft Ni matrix, i.e. it was found to increase with the P-content of the Ni-P coating. The extrapolated value for the micro-hardness of the Ni3P phase is found about 757 ± 20 HV0.01.

  11. Experimental evaluation of optimization method for developing ultraviolet barrier coatings

    Science.gov (United States)

    Gonome, Hiroki; Okajima, Junnosuke; Komiya, Atsuki; Maruyama, Shigenao

    2014-01-01

    Ultraviolet (UV) barrier coatings can be used to protect many industrial products from UV attack. This study introduces a method of optimizing UV barrier coatings using pigment particles. The radiative properties of the pigment particles were evaluated theoretically, and the optimum particle size was decided from the absorption efficiency and the back-scattering efficiency. UV barrier coatings were prepared with zinc oxide (ZnO) and titanium dioxide (TiO2). The transmittance of the UV barrier coating was calculated theoretically. The radiative transfer in the UV barrier coating was modeled using the radiation element method by ray emission model (REM2). In order to validate the calculated results, the transmittances of these coatings were measured by a spectrophotometer. A UV barrier coating with a low UV transmittance and high VIS transmittance could be achieved. The calculated transmittance showed a similar spectral tendency with the measured one. The use of appropriate particles with optimum size, coating thickness and volume fraction will result in effective UV barrier coatings. UV barrier coatings can be achieved by the application of optical engineering.

  12. Evaluation of stability for monolayer injection molding tools coating

    DEFF Research Database (Denmark)

    Cech, Jiri; Taboryski, Rafael J.

    2012-01-01

    We tested and characterized molecular coating of Aluminium and Nickel prototype molds and mold inserts for polymer replication via injection molding (IM). X-Ray photoelectron spectroscopy (XPS) data, sessile drop contact angles with multiple fluids, surface energy and roughness data have been....... Detectable coating presence was indicated by an increased angle on all post IM samples. To conclude, we present mold coating evaluation method, which is well suited for ultrathin, controlable, covalently bonded coating, that is reasonably durable, affordable, scalable to production, detectable on surface...... and especially suitable for rapid prototyping and mold geometry testing....

  13. Evaluation of seed priming and coating on emergence, yield and ...

    African Journals Online (AJOL)

    Evaluation of seed priming and coating on emergence, yield and yield components of bread wheat. (Triticum aestivum ... and cow urine primed + Dynamic 200 FS + Disco™ AG Red L-431 + Genius coat™ coated seeds were tested using RCBD with .... fertilizer dose of 92 kg ha-1 N and 46 kg ha-1 P2O5 was used for both ...

  14. A field evaluation of coated urea with biodegradable materials and ...

    African Journals Online (AJOL)

    Urease inhibitor and biodegradable polymer coatings are two most suitable startegies to increase urea fertilizer efficiency. Coating of urea with selected inhibitors can increase the crop production by slowing down the hydrolysis process of urea in the soil. For this purpose, a field experiment was conducted to evaluate the ...

  15. Evaluation of factors influencing transmissivity in fractured hard-rock ...

    African Journals Online (AJOL)

    such as geomorphology (topography), lithology, brittle (neo-) tectonics, and surface-water hydrology, all play a significant role in the occurrence of groundwater in hard-rock environ- ments, because together they control the: • Nature and depth of the regolith. • Development of fracture and fault zones. • Presence of higher ...

  16. School Psychological Evaluation Reports for Deaf and Hard of Hearing Children: Best Practices.

    Science.gov (United States)

    Whitaker, Robert; Thomas-Presswood, Tania

    2017-01-01

    This article discusses the best practices for school psychological evaluation and reports for parents and professionals who work with deaf and hard of hearing children. Deaf and hard of hearing children present unique challenges and for parents to be strong advocates for their children, knowledge about the complexities of psychological assessments is important. Parents are also provided with best practices for psychological reports with descriptions for typical areas of reports and how each is different for deaf and hard of hearing children.

  17. Trackless tack coat materials : a laboratory evaluation performance acceptance.

    Science.gov (United States)

    2012-06-01

    The purpose of this study was to develop, demonstrate, and document laboratory procedures that could be used by the : Virginia Department of Transportation (VDOT) to evaluate non-tracking tack coat materials. The procedures would be used to : qualify...

  18. Evaluation of antimicrobial edible coatings from a whey protein isolate base to improve the shelf life of cheese.

    Science.gov (United States)

    Ramos, Ó L; Pereira, J O; Silva, S I; Fernandes, J C; Franco, M I; Lopes-da-Silva, J A; Pintado, M E; Malcata, F X

    2012-11-01

    The objective of this work was to evaluate the effectiveness of antimicrobial edible coatings to wrap cheeses, throughout 60 d of storage, as an alternative to commercial nonedible coatings. Coatings were prepared using whey protein isolate, glycerol, guar gum, sunflower oil, and Tween 20 as a base matrix, together with several combinations of antimicrobial compounds-natamycin and lactic acid, natamycin and chitooligosaccharides (COS), and natamycin, lactic acid, and COS. Application of coating on cheese decreased water loss (~10%, wt/wt), hardness, and color change; however, salt and fat contents were not significantly affected. Moreover, the antimicrobial edible coatings did not permit growth of pathogenic or contaminant microorganisms, while allowing regular growth of lactic acid bacteria throughout storage. Commercial nonedible coatings inhibited only yeasts and molds. The antimicrobial edible coating containing natamycin and lactic acid was the best in sensory terms. Because these antimicrobial coatings are manufactured from food-grade materials, they can be consumed as an integral part of cheese, which represents a competitive advantage over nonedible coatings. Copyright © 2012 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  19. Synthesis and characterisation of coating polyurethane cationomers containing fluorine built-in hard urethane segments.

    Science.gov (United States)

    Król, Bożena; Król, Piotr; Pikus, Stanisław; Chmielarz, Paweł; Skrzypiec, Krzysztof

    2010-08-01

    Polyurethane cationomers were synthesised in the reaction of 4,4'-methylenebis(phenyl isocyanate) with polyoxyethylene glycol (M = 2,000) or poly(tetrafluoroethyleneoxide-co-difluoromethylene oxide) α,ω-diisocyanate and N-methyl diethanolamine. Amine segments were built-in to the urethane-isocyanate prepolymer in the reaction with 1-bromobutane or formic acid, and then they were converted to alkylammonium cations. The obtained isocyanate prepolymers were then extended in the aqueous medium that yielded stable aqueous dispersions which were applied on the surfaces of test poly(tetrafluoroethylene) plates. After evaporation of water, the dispersions formed thin polymer coatings. (1)H, (13)C NMR and IR spectral methods were employed to confirm chemical structures of synthesised cationomers. Based on (1)H NMR and IR spectra, the factors κ and α were calculated, which represented the polarity level of the obtained cationomers. The DSC, wide angle X-ray scattering and atom force microscopy methods were employed for the microstructural assessment of the obtained materials. Changes were discussed in the surface free energy and its components, as calculated independently according to the method suggested by van Oss-Good, in relation to chemical and physical structures of cationomers as well as morphology of coating surfaces obtained from those cationomers. Fluorine incorporated into cationomers (about 30%) contributed to lower surface free energy values, down to about 15 mJ/m(2). That was caused by gradual weakening of long-range interactions within which the highest share is taken by dispersion interactions.

  20. Gas turbine coatings eddy current quantitative and qualitative evaluation

    Science.gov (United States)

    Ribichini, Remo; Giolli, Carlo; Scrinzi, Erica

    2017-02-01

    Gas turbine blades (buckets) are among the most critical and expensive components of the engine. Buckets rely on protective coatings in order to withstand the harsh environment in which they operate. The thickness and the microstructure of coatings during the lifespan of a unit are fundamental to evaluate their fitness for service. A frequency scanning Eddy Current instrument can allow the measurement of the thickness and of physical properties of coatings in a Non-Destructive manner. The method employed relies on the acquisition of impedance spectra and on the inversion of the experimental data to derive the coating properties and structure using some assumptions. This article describes the experimental validation performed on several samples and real components in order to assess the performance of the instrument as a coating thickness gage. The application of the technique to support residual life assessment of serviced buckets is also presented.

  1. Evaluation of encapsulating coatings on the performance of polypyrrole actuators

    Science.gov (United States)

    Naficy, Sina; Stoboi, Nicholas; Whitten, Philip G.; Spinks, Geoffrey M.; Wallace, Gordon G.

    2013-07-01

    Conjugated polymer actuators are electroactive materials capable of generating force and movement in response to an applied external voltage. Many potential biomedical and industrial applications require these actuators to operate in a liquid environment. However, immersion of uncoated conducting polymer actuators in non-electrolyte liquids greatly reduces their operating lifetime. Here, we demonstrate the use of spray coating as an effective and simple method to encapsulate polypyrrole (PPy) tri-layer bending actuators. Poly(styrene-b-isobutylene-b-styrene) (SIBS) was used as an encapsulating, compliant spray coating on PPy actuators. A significant enhancement in actuator lifetime in both air and water was observed by encapsulating the actuators. The change in stiffness and reduction in bending amplitude for coatings of different thickness was studied. A simple beam mechanics model describes the experimental results and highlights the importance of coating compliance for actuator coatings. The model may be used to evaluate other possible encapsulating materials.

  2. Production of hard hydrophilic Ni-B coatings on hydrophobic Ni-Ti and Ti-6Al-4V alloys by electroless deposition

    Energy Technology Data Exchange (ETDEWEB)

    Buelbuel, Ferhat; Karabudak, Filiz; Yesildal, Ruhi [Ataturk Univ., Erzurum (Turkey). Mechanical Engineering Dept.

    2017-07-01

    This paper is mainly focused on the wetting state of liquid droplets on Ni-Ti and Ti-6Al-4V hierarchical structured hydrophobic surfaces in micro/nanoscale. Electroless Ni-B deposition as a surface coating treatment has recently drawn considerable attention of researchers owing to remarkable advantages when compared with other techniques such as low price, conformal ability to coat substrates, good bath stability and relatively easier plating process control. The Ni-Ti and Ti-6Al-4V substrates were plated by electroless Ni-B plating process. The coated films were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), hardness testing and static contact angle measurement. Results obtained from the analyses show that electroless Ni-B deposition may improve the hardness and wettability of the Ni-Ti and Ti-6Al-4V alloy surfaces.

  3. Comparative evaluation of different thermally modified wood samples finishing with UV-curable and waterborne coatings

    Science.gov (United States)

    Herrera, René; Muszyńska, Monika; Krystofiak, Tomasz; Labidi, Jalel

    2015-12-01

    Thermally modified wood has been developed as an industrial method to improve durability and dimensional stability of wood and thus extends the range of uses and service life of wood-based products. Despite the improvements gained by treatment, surface finishing using coatings prevents esthetical changes such as color degradation or occasional growth of mold adding protection in outdoor use and extending the service life of products. The wood finishing process was carried out with commercially available waterborne and UV-curable coatings on industrially modified at 192, 200, 212 °C and unmodified European ash (Fraxinus excelsior L.) wood, using an industrial rollers system and a laboratory brushing system. Changes caused by thermal treatment which could affect the surface finish were measured and compared with control samples, such as water uptake, wettability and acidity. Following the wood finishing, surface properties and esthetic changes were evaluated; as well as the coatings performance. Thermally modified wood presented improved adherence compared with unmodified wood with a significant improvement in samples modified at 212 °C, which also present the highest hardness when UV-cured. Finishes with UV-curing maintain the hydrophobic effect of thermally modified wood, whereas waterborne finishes increase the surface wettability. Thermal modification did not negatively influence on the elastic properties of the coated substrate and thus allows this material to be finished with different coating systems in the same conditions as unmodified wood.

  4. Biological evaluation of ultrananocrystalline and nanocrystalline diamond coatings.

    Science.gov (United States)

    Skoog, Shelby A; Kumar, Girish; Zheng, Jiwen; Sumant, Anirudha V; Goering, Peter L; Narayan, Roger J

    2016-12-01

    Nanostructured biomaterials have been investigated for achieving desirable tissue-material interactions in medical implants. Ultrananocrystalline diamond (UNCD) and nanocrystalline diamond (NCD) coatings are the two most studied classes of synthetic diamond coatings; these materials are grown using chemical vapor deposition and are classified based on their nanostructure, grain size, and sp(3) content. UNCD and NCD are mechanically robust, chemically inert, biocompatible, and wear resistant, making them ideal implant coatings. UNCD and NCD have been recently investigated for ophthalmic, cardiovascular, dental, and orthopaedic device applications. The aim of this study was (a) to evaluate the in vitro biocompatibility of UNCD and NCD coatings and (b) to determine if variations in surface topography and sp(3) content affect cellular response. Diamond coatings with various nanoscale topographies (grain sizes 5-400 nm) were deposited on silicon substrates using microwave plasma chemical vapor deposition. Scanning electron microscopy and atomic force microscopy revealed uniform coatings with different scales of surface topography; Raman spectroscopy confirmed the presence of carbon bonding typical of diamond coatings. Cell viability, proliferation, and morphology responses of human bone marrow-derived mesenchymal stem cells (hBMSCs) to UNCD and NCD surfaces were evaluated. The hBMSCs on UNCD and NCD coatings exhibited similar cell viability, proliferation, and morphology as those on the control material, tissue culture polystyrene. No significant differences in cellular response were observed on UNCD and NCD coatings with different nanoscale topographies. Our data shows that both UNCD and NCD coatings demonstrate in vitro biocompatibility irrespective of surface topography.

  5. Mechanical and Tribological Properties of PVD-Coated Cemented Carbide as Evaluated by a New Multipass Scratch-Testing Method

    Directory of Open Access Journals (Sweden)

    M. Fallqvist

    2012-01-01

    Full Text Available A new test method based on multipass scratch testing has been developed for evaluating the mechanical and tribological properties of thin, hard coatings. The proposed test method uses a pin-on-disc tribometer and during testing a Rockwell C diamond stylus is used as the “pin” and loaded against the rotating coated sample. The influence of normal load on the number of cycles to coating damage is investigated and the resulting coating damage mechanisms are evaluated by posttest scanning electron microscopy. The present study presents the test method by evaluating the performance of Ti0.86Si0.14N, Ti0.34Al0.66N, and (Al0.7Cr0.32O3 coatings deposited by cathodic arc evaporation on cemented carbide inserts. The results show that the test method is quick, simple, and reproducible and can preferably be used to obtain relevant data concerning the fatigue, wear, chipping, and spalling characteristics of different coating-substrate composites. The test method can be used as a virtually nondestructive test and, for example, be used to evaluate the fatigue and wear resistance as well as the cohesive and adhesive interfacial strength of coated cemented carbide inserts prior to cutting tests.

  6. Transparent and hard zirconia-based hybrid coatings with excellent dynamic/thermoresponsive oleophobicity, thermal durability, and hydrolytic stability.

    Science.gov (United States)

    Masheder, Benjamin; Urata, Chihiro; Hozumi, Atsushi

    2013-08-28

    Smooth, transparent, and extremely hard zirconia (ZrO2)-based inorganic-organic hybrid films showing excellent dynamic oleophobicity, thermal durability, and hydrolytic stability were successfully prepared through a simple combination of zirconium tetrapropoxide (Zr(O(CH2)2CH3)4) with stearic acids. In this study, we have particularly focused on the effects of stearic acid molecular architecture (linear-stearic acid (LSA) and branched-stearic acid (BSA)) on surface physical/chemical properties. Although, in each case, the resulting hybrid (Zr:LSA and Zr:BSA) films achieved by a simple spin-coating method were highly smooth and transparent, the final surface properties were markedly dependent on their molecular architectures. Thanks to the thermal stability of BSA, our Zr:BSA hybrid films displayed a greatly improved thermal effective range (maximum of 200 °C), while for Zr:LSA hybrid films, serious thermal damage to surface dewetting behavior was observed at less than 150 °C. The hardness of the Zr:BSA hybrid films were markedly increased by curing at 200 °C for 1 h (from 1.95 GPa to 3.03 GPa), while maintaining their dynamic dewettability toward n-hexadecane, when compared with Zr:LSA hybrid films (0.95-1.19 GPa). Small volume n-hexadecane droplets (5 μL) were easily set in motion, sliding across and off our best Zr:BSA hybrid film surfaces at low substrate tilt angles (<10°) without pinning. Moreover, they also showed thermoresponsive dynamic dewetting behavior, reasonable resistance to hydrolysis in an aqueous environment, and antifingerprint properties.

  7. Evaluation of Coatings for FR-4 Fiberglass Epoxy Composite Probes

    Science.gov (United States)

    2014-01-01

    repair coating for resurfacing and reforming metal machinery and equipment, such as pumps , impellers , fans, valves, and pipe elbows (3). This...NOTICES Disclaimers The findings in this report are not to be construed as an official Department of the Army position unless so designated by...Evaluation of Coatings for FR-4 Fiberglass Epoxy Composite Probes 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR( S

  8. Evaluation of Thermal Endurance Characteristics of Hard Polyurethane Foams by Dynamic Compression Modulus

    National Research Council Canada - National Science Library

    Adachi, Hiromasa; Hasegawa, Teruo

    2004-01-01

      For evaluation of thermal endurance in foamed plastics, temperature and time characteristics of compression dynamic modulus of four hard polyurethane foams were investigated by the dynamic viscoelastic measurements...

  9. Effect of a Shot Peening Pre Treatment on the Fatigue Behaviour of Hard Chromium on Electroless Nickel Interlayer Coated AISI 4340 Aeronautical Steel

    Directory of Open Access Journals (Sweden)

    Nascimento Marcelino P.

    2002-01-01

    Full Text Available Multiple layer systems of coatings are considered to have larger resistance to crack propagation in comparison to coatings with simple layer. With regard to fatigue, it is possible to improve the resistance of a component with the application of shot peening treatment, whose compressive residual stresses delay or eliminate the initiation and propagation of fatigue cracks. The aim of this study is to analyse the effects on rotating bending fatigue behaviour of hard chromium fraction three-quarters electroless nickel multilayer system coated AISI 4340 high strength steel submitted to shot peening pre treatment. Results indicated that the interaction between the shot peening process with the multilayer system was not satisfactory, resulting in intense delamination. Fracture surface analysis by SEM was performed toward to identify the fatigue crack origin, as well as the coating-substrate delamination process.

  10. Protective effects of resin sealant and flowable composite coatings against erosive and abrasive wear of dental hard tissues.

    Science.gov (United States)

    Zhao, Xiaoyi; Pan, Jie; Malmstrom, Hans S; Ren, Yan-Fang

    2016-06-01

    To test the effectiveness of sealant and flowable composite coating on eroded enamel, dentin and cementum under erosive/abrasive challenges in vitro. A total of 108 tissue sections (36 each for enamel, dentin and cementum) from third molars were assigned to three groups: Seal & Protect sealant (S&P), Tetric EvoFlow composite (TEF) and control. Erosive/abrasive lesions were created on each specimen by citric acid and brushing with toothpaste. S&P and TEF were applied to the lesions and subjected to erosive/abrasive cycling included 24 cycles of immersion in citric acid (pH 3.6) for 60min, followed by remineralization for 120min and brushing with toothpastes for 600 strokes at 150g. Erosive wear of materials or dental tissues were measured with 3D scanning microscopy and data were analyzed using ANOVA. Treatments with S&P and TEF created a protective material coating of 42.7±17.8μm and 150.8±9.9μm in thickness, respectively. After 24 cycles of erosive/abrasive challenges, tissue losses were -346.9±37.3μm for enamel, -166.5±26.3μm for dentin and -164.7±18.2μm for cementum in untreated controls, as compared to material losses of -24.4±3.3μm for S&P, and -10.8±4.4μm for TEF, respectively. Both S&P and TEF were effective in protecting enamel, dentin and cementum against erosive tooth wear (ppeeling in a third of the specimens. TEF remained intact on all three types of dental tissues at the end of the 24 cycles of erosive/abrasive challenges. A thin coating of flowable composite resin 150μm in thickness may provide long-term protection against erosive/abrasive tooth wear. Resin sealant may provide adequate protection for dental hard tissues in short-term and may require repeated applications if long-term protection is desired. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Evaluation of an enteric-coated naproxen pellet formulation.

    Science.gov (United States)

    Hardy, J G; Lamont, G L; Evans, D F; Haga, A K; Gamst, O N

    1991-02-01

    An enteric-coated, pellet formulation of naproxen has been evaluated in eight healthy subjects. Each volunteer was dosed with 153Sm-labelled, enteric-coated pellets on two occasions, once whilst fasted and once after breakfast. Gastrointestinal transit was followed using gamma scintigraphy and drug absorption compared with that from uncoated naproxen pellets dosed on a separate occasion. The pH in the stomach and intestines was monitored using radiotelemetry capsules. Gastric emptying was delayed by dosing after breakfast, but small intestinal transit of the enteric-coated formulation was the same on both occasions. The highest pH recorded from the stomach was 4.0 and in all subjects the pH rose to at least 7.3 in the small intestine. The onset of drug absorption was fastest from the uncoated formulation and slowest from the coated pellets taken after breakfast. The total amount of drug absorbed was the same on all three occasions.

  12. Evaluation of several corrosion protective coating systems on aluminum

    Science.gov (United States)

    Higgins, R. H.

    1981-01-01

    A study of several protective coating systems for use on aluminum in seawater/seacoast environments was conducted to review the developments made on protective coatings since early in the Space Shuttle program and to perform comparative studies on these coatings to determine their effectiveness for providing corrosion protection during exposure to seawater/seacoast environments. Panels of 2219-T87 aluminum were coated with 21 different systems and exposed to a 5 percent salt spray for 4000 hr. Application properties, adhesion measurements, heat resistance and corrosion protection were evaluated. For comparative studies, the presently specified Bostik epoxy system used on the SRB structures was included. Results of these tests indicate four systems with outstanding performance and four additional systems with protection almost as good. These systems are based on a chromated pretreatment, a chromate epoxy primer, and a polyurethane topcoat. Consideration for one of these systems should be included for those applications where superior corrosion protection for aluminum surfaces is required.

  13. Effect of ion implantation on fatigue strength of martensitic stainless steel and surface hardness evaluation by ultra micro hardness tester

    Energy Technology Data Exchange (ETDEWEB)

    Tanaka, Tsuneshichi [Ritsumeikan Univ., Kyoto (Japan). Faculty of Science and Engineering; Nakayama, Hideaki; Kato, Masahiko

    1995-02-01

    The effect of surface modification by ion implantation on the fatigue strength of 13Cr martensitic stainless steel was first described. Then the relationship between the fatigue performance and the surface microhardness of the material was dealt with. N{sup +} ions were implanted into the specimen surface with doses in the range of 5x10{sup 13} ions/cm{sup 2} - 5x10{sup 17} ions/cm{sup 2} with energy level of 350 keV. The results of out-of-plane bending fatigue tests revealed that the fatigue strength was improved by the ion implantation with implantation doses more than 2x10{sup 17} ions/cm{sup 2}, and that the further increase of fatigue strength was attained by the post heat treatment following the ion implantation. The microhardness of ultra-thin surface layer of submicron order was evaluated by the method previously proposed by the authors. The results indicated that the surface layer was hardened by the ion implantation and the hardness was increased by the post heat treatment. A remarkable increase in hardness was observed at the surface layer after the fatigue test, and this increase of the microhardness well coincides with the improvement of fatigue strength by ion implantation and post heat treatment. (author).

  14. DIFFUSIVELY ALLOYED COMPOUNDS MADE OF METAL DISCARD WITH A REDUCED MELTING TEMPERATURE FOR OBTAINING WEAR RESISTANT COATINGS USING INDUCTION HARD-FACING TECHNOLOGIES

    Directory of Open Access Journals (Sweden)

    V. G. Shcherbakou

    2016-01-01

    Full Text Available The technology of obtaining diffusion doped alloys made from metal scrap is reviewed in the article. The influence of short term preprocessing at high temperature on structure formation by concentrated energy sources within the further induction deposit is reviewed. A mechanism of a contact eutectic melting in diffusion doped alloys at short term high temperature treatment is described and suggested in this work. It was shown that such kind of processing of diffusion doped alloys is a perspective way of treatment when using induction hard-facing technologies for obtaining wear resistant coatings. A resource and energy saving technology was developed for obtaining wear resistant coatings based on diffusion doped alloys from metal scrap treated using induction hard-facing process.

  15. EVALUATION OF MANDIBULAR HARD AND SOFT TISSUES IN CLEFT PATIENTS*

    Directory of Open Access Journals (Sweden)

    Işıl ARAS

    2017-04-01

    Full Text Available Purpose: The aim of this study was to compare the mandibular hard and soft tissue measurements of unilateral and bilateral cleft lip and palate patients with non-cleft individuals. Materials and Methods: The study sample comprised of lateral cephalograms of 45 subjects. Sample included 15 non-cleft (NC, 15 unilateral cleft lip and palate (UCLP and 15 bilateral cleft lip and palate (BCLP cases whose age were between 15 to 17. 1 angular 13 linear measurements were carried out using Arnett and Gunson soft tissue cephalometric analysis and 4 angular measurements were calculated with Steiner Analysis. Results: Mandibular incisor inclinations relative to the occlusal plane (Md1-Md OP were significantly greater and mandibular incisor projections (Md1-TVL were significantly retrusive in cleft subjects (p<0.05. Projection values pertaining to lower lip anterior (LLA-TVL, soft tissue B point (B’-TVL, and soft tissue pogonion (Pog’-TVL were significantly deficient as well in cleft patients (p<0.05. Sagittal position of the maxilla (SNA (p<0.001 and intermaxillary relation of the jaws (ANB were significantly deficient in UCLP subjects (p<0.05 and BCLP individuals (p<0.01. LLA-TVL and B’-TVL correlated with SNB in cleft patients (p<0.05. Conclusion: Decreased lower lip and chin projection values suggest that mandibular region of cleft patients should be taken into account in forming the treatment plan to improve the esthetic outcome of orthodontic and plastic surgery interventions.

  16. Evaluation of the Various Drying Methods on Surface Hardness of Type IV Dental Stone

    OpenAIRE

    Sudhakar, A.; Srivatsa, G.; Shetty, Rohit; Rajeswari, C L; Manvi, Supriya

    2015-01-01

    Background: Studies regarding the effect of various methods to increase the surface hardness of Type IV dental stone are not conclusive. Therefore, this study was carried out to evaluate the effect of air drying, micro oven drying and die hardener on surface hardness of Type IV dental stone. Materials and Methods: A standard metal die was fabricated; polyvinyl siloxane impression material was used to make the molds of metal die. A total of 120 specimens were obtained from two different die st...

  17. Evaluation of hard gelatin capsules and hydroxypropyl methylcellulose containing ampicillin

    Directory of Open Access Journals (Sweden)

    Graziella Gonçalves Weigert

    2012-01-01

    Full Text Available This study aims to develop and evaluate formulations containing ampicillin in capsules of gelatin and hydroxypropyl methylcellulose (HPMC. Two formulations (A and B were developed. The final product quality was evaluated by testing for quality control and the results were in agreement with the Brazilian Pharmacopoeia. The formulations with HPMC capsules showed lower percentages of drug dissolved (99.67%, HPMC-A and 87.70%, HPMC-B than the gelatin (100.18%, GEL-A and 101.16% GEL-B. Because of the delay of the ampicillin release observed in the dissolution profiles, it becomes necessary to evaluate the drugs that can be conditioned in the HPMC capsules.

  18. Evaluation of Glider Coatings against Biofouling for Improved Flight Performance

    Science.gov (United States)

    2010-09-30

    We received 10 different samples from UCSD/Scripps, operating the spray glider . There was one sample from Webb Research Inc., operating the slocum ...three glider types (Spray, Slocum , and Seaglider) in the biofoulingassessment field site in Morro Bay, CA. Samples will be maintained and...DISTRIBUTION STATEMENT A. Approved for public release; distribution is unlimited. Evaluation of Glider Coatings against Biofouling for Improved

  19. Evaluation of ERINA Plus as a coat conditioner in canines

    Directory of Open Access Journals (Sweden)

    Srivastava

    Full Text Available Coat conditioning, deodorant and cleansing properties of ERINA Plus were evaluated in fifty-one dogs of different breeds. More than 80% of dogs showed good to excellent conditioning, deodorant and cleansing effects supported ERINA Plus as safe conditioner shampoo. [Vet. World 2008; 1(12.000: 361-362

  20. Evaluation of the Various Drying Methods on Surface Hardness of Type IV Dental Stone

    Science.gov (United States)

    Sudhakar, A; Srivatsa, G; Shetty, Rohit; Rajeswari, C L; Manvi, Supriya

    2015-01-01

    Background: Studies regarding the effect of various methods to increase the surface hardness of Type IV dental stone are not conclusive. Therefore, this study was carried out to evaluate the effect of air drying, micro oven drying and die hardener on surface hardness of Type IV dental stone. Materials and Methods: A standard metal die was fabricated; polyvinyl siloxane impression material was used to make the molds of metal die. A total of 120 specimens were obtained from two different die stones and were grouped as Group A (kalrock) and Group B (pearl stone), and were subjected to air drying for 24 h, micro oven drying and application of die hardener. These models were then subjected to surface hardness testing using the knoop hardness instrument. The obtained data were subjected to statistical analysis. Results: The hardness of Group A specimens was 64 ± 0.54 Knoop hardness number (KHN) after application of die hardener, 60.47 ± 0.41 KHN after 24 h air drying, 58.2 ± 0.88 after microwave oven drying and 24.6 ± 0.4 after 1 h air drying. The hardness of Group B specimens was 45.59 ± 0.63 KHN after application of die hardener, 40.2 ± 0.63 KHN after 24 h air drying, 38.28 ± 0.55 KHN after microwave oven drying and 19.91 ± 0.64 KHN after 1 h air drying. Conclusion: Group A showed better results than Group B at all times. Application of the die hardener showed highest hardness values followed in the order by 24 h air drying, microwave oven drying and 1 h air drying in both groups. The study showed that air drying the dies for 24 h followed by application of a single layer of the die hardener produced the best surface hardness and is recommended to be followed in practice. PMID:26124610

  1. Evaluation of the Various Drying Methods on Surface Hardness of Type IV Dental Stone.

    Science.gov (United States)

    Sudhakar, A; Srivatsa, G; Shetty, Rohit; Rajeswari, C L; Manvi, Supriya

    2015-06-01

    Studies regarding the effect of various methods to increase the surface hardness of Type IV dental stone are not conclusive. Therefore, this study was carried out to evaluate the effect of air drying, micro oven drying and die hardener on surface hardness of Type IV dental stone. A standard metal die was fabricated; polyvinyl siloxane impression material was used to make the molds of metal die. A total of 120 specimens were obtained from two different die stones and were grouped as Group A (kalrock) and Group B (pearl stone), and were subjected to air drying for 24 h, micro oven drying and application of die hardener. These models were then subjected to surface hardness testing using the knoop hardness instrument. The obtained data were subjected to statistical analysis. The hardness of Group A specimens was 64 ± 0.54 Knoop hardness number (KHN) after application of die hardener, 60.47 ± 0.41 KHN after 24 h air drying, 58.2 ± 0.88 after microwave oven drying and 24.6 ± 0.4 after 1 h air drying. The hardness of Group B specimens was 45.59 ± 0.63 KHN after application of die hardener, 40.2 ± 0.63 KHN after 24 h air drying, 38.28 ± 0.55 KHN after microwave oven drying and 19.91 ± 0.64 KHN after 1 h air drying. Group A showed better results than Group B at all times. Application of the die hardener showed highest hardness values followed in the order by 24 h air drying, microwave oven drying and 1 h air drying in both groups. The study showed that air drying the dies for 24 h followed by application of a single layer of the die hardener produced the best surface hardness and is recommended to be followed in practice.

  2. Effect of KOH to Na2SiO3 Ratio on Microstructure and Hardness of Plasma Electrolytic Oxidation Coatings on AA 6061 Alloy

    Science.gov (United States)

    Sharma, Ashutosh; Jang, Yong-Joo; Jung, Jae Pil

    2017-10-01

    In this study, plasma electrolytic oxidation (PEO) process has been employed to fabricate alumina coatings on AA 6061 aluminum alloy from an electrolyte containing water glass (Na2SiO3) and alkali (KOH). The effect of deposition time and the alkali to water glass (KOH: Na2SiO3) composition ratio on the coating morphology and properties are studied. The different phases of the oxide layer and microstructure are investigated by x-ray diffraction, scanning electron microscopy, and atomic force microscopy. The results indicate that initially γ-Al2O3 forms in the coating, and as the processing time is increased from 5 to 60 minutes, α-Al2O3 phase becomes prominent. Further, higher the content of Na2SiO3, higher is the hardness and coating growth rate due to the formation of stable α-Al2O3 and Al-Si-O phase. It has been reported that the optimum properties of the PEO coatings can be obtained at a ratio of KOH: Na2SiO3 ≈ 15:10 followed by 10:10.

  3. Effect of KOH to Na2SiO3 Ratio on Microstructure and Hardness of Plasma Electrolytic Oxidation Coatings on AA 6061 Alloy

    Science.gov (United States)

    Sharma, Ashutosh; Jang, Yong-Joo; Jung, Jae Pil

    2017-09-01

    In this study, plasma electrolytic oxidation (PEO) process has been employed to fabricate alumina coatings on AA 6061 aluminum alloy from an electrolyte containing water glass (Na2SiO3) and alkali (KOH). The effect of deposition time and the alkali to water glass (KOH: Na2SiO3) composition ratio on the coating morphology and properties are studied. The different phases of the oxide layer and microstructure are investigated by x-ray diffraction, scanning electron microscopy, and atomic force microscopy. The results indicate that initially γ-Al2O3 forms in the coating, and as the processing time is increased from 5 to 60 minutes, α-Al2O3 phase becomes prominent. Further, higher the content of Na2SiO3, higher is the hardness and coating growth rate due to the formation of stable α-Al2O3 and Al-Si-O phase. It has been reported that the optimum properties of the PEO coatings can be obtained at a ratio of KOH: Na2SiO3 ≈ 15:10 followed by 10:10.

  4. Thin films and coatings toughening and toughness characterization

    CERN Document Server

    Zhang, Sam

    2015-01-01

    Thin Films and Coatings: Toughening and Toughness Characterization captures the latest developments in the toughening of hard coatings and in the measurement of the toughness of thin films and coatings. Featuring chapters contributed by experts from Australia, China, Czech Republic, Poland, Singapore, Spain, and the United Kingdom, this first-of-its-kind book:Presents the current status of hard-yet-tough ceramic coatingsReviews various toughness evaluation methods for films and hard coatingsExplores the toughness and toughening mechanisms of porous thin films and laser-treated surfacesExamines

  5. Performance Evaluation of Received Signal Strength Based Hard Handover for UTRAN LTE

    DEFF Research Database (Denmark)

    Anas, Mohmmad; Calabrese, Francesco Davide; Mogensen, Preben

    2007-01-01

    This paper evaluates the hard handover performance for UTRAN LTE system. The focus is on the impact that received signal strength based hard handover algorithm have on the system performance measured in terms of number of handovers, time between two consecutive handovers and uplink SINR for a user...... about to experience a handover. A handover algorithm based on received signal strength measurements has been designed and implemented in a dynamic system level simulator and has been studied for different parameter sets in a 3GPP UTRAN LTE recommended simulation scenario. The results suggest...

  6. Investigation of the Wear and Hardness Behaviour of Aluminium Alloy Coated Using the Powder Flame Spraying Method

    Directory of Open Access Journals (Sweden)

    Nurullah KIRATLI

    2009-03-01

    Full Text Available In this study, the wear behavior of aluminum alloy AL 5754 ( Etial 53 coated with powders of 10Al-Cu alloy (RotoTec® 19850 and 15Cr7Fe-Ni alloy (RotoTec® 19985 using powder flame spraying method has been investigated. To avoid thermal expansions between substrate and coating materials, Ni-Al RotoTec® 51000 was used as binding material. The wear test was performed on a pin-on-disc test apparatus. As an abrasive material, a SiC, 800 sandpaper was used. The wear tests of coated materials were carried out at room temperature and at 1.0m/s sliding speed with 0.35 and 0.70MPa pressures. To characterize coated specimens, they have been examined with optical microscope. As a result, it is found that the both coating materials have improved wear resistance.

  7. Development and evaluation of a hot-melt coating technique for enteric coating

    Directory of Open Access Journals (Sweden)

    Arun Trambak Patil

    2012-03-01

    Full Text Available Conventional enteric coating requires the use of organic based polymers which are equally hazardous to the environment and operating personnel. Hot-melt coating avoids the use of solvents and is a safer and time-saving process. The present study was designed to assess the efficacy of hot-melt coating (HMC as an enteric coating technique. Pellets prepared by extrusion spheronization were selected as the core formulation for a model of the gastric irritant drug diclofenac sodium (DFS because of their innate advantages over single-unit formulations. Stearic acid (SA and palmitic acid (PA were evaluated as enteric hot-melt coating materials. HMC was carried out in a specially modified coating pan by applying SA and PA in molten state onto preheated pellets to achieve a coating level of 5-15 %w/w. Hot-melt coated pellets were evaluated for disintegration pH and in vitro dissolution in the pH range 1.2 to 6.8, along with basic micromeritics. SEM of coated pellets showed a uniform and smooth coating. These results indicated that HMC of both SA and PA exhibited very good enteric coating ability. The coated pellets showed negligible drug release in acidic pH. As the pellets were subsequently transferred to a higher pH level, a gradual increase in release of the drug from the pellets was observed with increasing pH of the dissolution media. The release was dependent upon coating extent, providing sustained enteric release as opposed to abrupt release with mixed release kinetics.O revestimento entérico convencional requer o uso de polímeros orgânicos os quais são igualmente danosos ao meio ambiente e ao pessoal que o executa. O revestimento por fusão a quente evita o uso de solventes e é processo mais seguro e que consome menos tempo. O presente estudo foi planejado para avaliar a eficácia do revestimento por fusão a quente (RFQ como técnica de revestimento entérico. Os péletes preparados por esferonização por extrusão foram selecionados como

  8. 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.

    Science.gov (United States)

    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.

  9. Hardness evaluation of prosthetic silicones containing opacifiers following chemical disinfection and accelerated aging

    Directory of Open Access Journals (Sweden)

    Marcelo Coelho Goiato

    2010-09-01

    Full Text Available We evaluated the effects of disinfection and aging on the hardness of silicones containing opacifiers and intended for use in facial prosthetics. A total of 90 samples were produced using a cylindrical metal mold 3 mm in height and 30 mm in diameter. The samples were fabricated from Silastic MDX 4-4210 silicone in three groups: GI contained no opacifier, GII contained barium sulfate (Ba, and GIII contained titanium dioxide (Ti. The samples were disinfected using effervescent tablets (Ef, neutral soap (Ns, or 4% chlorhexidine (Cl 3 times a week for 60 days. After this period the samples underwent 1,008 hours of accelerated aging. The hardness was measured using a durometer immediately following the disinfection period and after 252, 504, and 1,008 hours of aging. The data were statistically analyzed using 3-way ANOVA and the Tukey test (p < .05. The GIII group exhibited the greatest variation in hardness regardless of elapsed time. All groups displayed greater hardness after 1,008 hours of accelerated aging independent of disinfectant type. All of the hardness values were within the clinically acceptable range.

  10. Evaluation of surface roughness and hardness of different glass ionomer cements

    Science.gov (United States)

    Bala, Oya; Arisu, Hacer Deniz; Yikilgan, Ihsan; Arslan, Seda; Gullu, Abdulkadir

    2012-01-01

    Objectives: The aim of this study was to evaluate surface roughness and hardness of a nanofiller GIC, a resin-modified GIC, three conventional GICs, and a silver-reinforced GIC. Methods: For each material, 11 spcecimens were prepared and then stored in distilled water at 37 °C for 24 h. The surface roughness of 5 specimens was measured using a surface profilometer before polishing and after polishing with coarse, medium, fine, superfine aluminum oxide abrasive Sof-Lex discs respectively. The hardness of the upper surfaces of the remaining 6 specimens was measured with a Vickers microhardness measuring instrument. Results: All tested GICs showed lower surface roughness values after the polishing procedure. Surface finish of nanofiller GIC was smoother than the other tested GICs after polishing. This was followed by resin-modified GIC, Fuji II LC; then silver-reinforced GIC, Argion Molar, conventional GICs, Aqua Ionofil Plus, Fuji IX, and Ionofil Molar, respectively. The result of the hardness test indicated that the microhardness value of silver-reinforced GIC was greater than that of the other GICs. When the hardness values of all tested GICs were compared, the differences between materials (except Aqua Ionofil Plus with Ionofil Molar and Ketac N100 with Fuji II LC (P>.05)) were found statistically significant (P<.05). Conclusions: According to the results of this study, it can be concluded that the differences in the composition of GICs may affect their surface roughness and hardness. PMID:22229011

  11. Evaluation of critical process parameters for intra-tablet coating uniformity using terahertz pulsed imaging.

    Science.gov (United States)

    Brock, Daniela; Zeitler, J Axel; Funke, Adrian; Knop, Klaus; Kleinebudde, Peter

    2013-11-01

    The purpose of this study was to evaluate the intra-tablet coating uniformity and the identification of critical process parameters in an active pan coating process using terahertz pulsed imaging (TPI). A design of experiments (DoE) was performed with drum load, drum speed, spray rate, run duration and spray pressure as factors. Different measures of intra-tablet uniformity were investigated: the average thickness on the individual tablet faces, spatial variation in layer thickness over the tablet surface, and the coefficient of variation (CV(intra)). Data analysis revealed that the process parameters in the investigated parameter space had hardly any influence on the difference in layer thickness of the tablet faces and centre band. No increase or decrease in layer thickness--as described in the literature--was found towards the edges of the tablet face. In overwetted process conditions a higher layer thickness at the centre band edges could be observed. Still, the highest variability in coating thickness was found along the circumference of the centre band rather than the height. In general, higher CV(intra) of layer thickness were found on the centre bands in comparison with the tablet faces. The analysis of the DoE model revealed that the run duration had the highest influence on the CV(intra) on the tablet faces. TPI showed high potential in the assessment of intra-tablet uniformity and layer thickness distributions over the whole tablet surface. It was successfully used to identify critical process parameters regarding intra-tablet coating uniformity. Copyright © 2013 Elsevier B.V. All rights reserved.

  12. Roughness Influence On Macro- And Micro-Tribology Of Multi-Layered Hard Coatings On Carbon Fibre Polymer Composite

    Directory of Open Access Journals (Sweden)

    Lackner J.M.

    2015-09-01

    Full Text Available Goal of this work is the investigation of roughness influences on the abrasive wear behaviour of magnetron sputtered multi-layered, low-friction coatings on carbon-fibre reinforced polymers (CFRP. Higher coating roughness at similar CFRP quality was realized by higher deposition rates, leading to increased heat flux to the substrates during deposition. Thermal expansion of the epoxy matrix on the micro scale results in a wavy, wrinkled surface topography. Both in scratch and reciprocal sliding testing against alumina, the friction coefficients are lower for the smooth coatings, but their wear rate is higher due to low-cycle fatigue caused abrasion.

  13. Performance evaluation of one coat systems for new steel bridges.

    Science.gov (United States)

    2011-06-01

    In an effort to address cost issues associated with shop application of conventional three-coat systems, the Federal : Highway Administration completed a study to investigate the performance of eight one-coat systems and two control : coatings for co...

  14. Hard coating of ultrananocrystalline diamond/nonhydrogenated amorphous carbon composite films on cemented tungsten carbide by coaxial arc plasma deposition

    Science.gov (United States)

    Naragino, Hiroshi; Egiza, Mohamed; Tominaga, Aki; Murasawa, Koki; Gonda, Hidenobu; Sakurai, Masatoshi; Yoshitake, Tsuyoshi

    2016-08-01

    Ultrananocrystalline diamond (UNCD)/nonhydrogenated amorphous carbon (a-C) composite (UNCD/a-C) films were deposited on cemented carbide containing Co by coaxial arc plasma deposition. With decreasing substrate temperature, the hardness was enhanced accompanied by an enhancement in the sp3/(sp2 + sp3). Energy-dispersive X-ray and secondary ion mass spectrometry spectroscopic measurements exhibited that the diffusion of Co atoms from the substrates into the films hardly occurs. The film deposited at room temperature exhibited the maximum hardness of 51.3 GPa and Young's modulus of 520.2 GPa, which evidently indicates that graphitization induced by Co in the WC substrates, and thermal deformation from sp3 to sp2 bonding are suppressed. The hard UNCD/a-C films can be deposited at a thickness of approximately 3 μm, which is an order larger than that of comparably hard a-C films. The internal compressive stress of the 51.3-GPa film is 4.5 GPa, which is evidently smaller than that of comparably hard a-C films. This is a reason for the thick deposition. The presence of a large number of grain boundaries in the film, which is a structural specific to UNCD/a-C films, might play a role in releasing the internal stress of the films.

  15. Chitosan coating and films : evaluation of surface, permeation, mechanical and thermal propertiess

    OpenAIRE

    Casariego, A.; Souza, B.W.S.; L. Cruz; Díaz, R; Teixeira, J. A.; A.A. Vicente

    2008-01-01

    The potentialities of chitosan (from lobster of the cuban coasts) coating to extend the shelf life of vegetables were evaluated. To do so, the surface properties of tomato and carrot were characterized and the wettability properties of chitosan coatings were studied. In such coatings, chitosan concentration and effects of type and concentration of plasticizer or surfactant on wettability of chitosan coatings were evaluated, as well as the respective barrier and mechanical properti...

  16. Performance Evaluation of Refractory Composite Coatings in Potassium Rich Environment

    Directory of Open Access Journals (Sweden)

    Kristina BRINKIENĖ

    2016-09-01

    Full Text Available A laboratory scale method was used to study the performance of reinforced cement composites in potassium rich environment of biomass combustion. Buckwheat husk (BH was used as potential source of unexploited biomass product applicable as biomass derived fuel. In order to enhance the alkali effect on the properties of the investigated materials, the solution of potassium carbonate (K2CO3 was selected as potassium rich aggressive environment. Two reinforced cement composites as potential repair coatings for restoration of damaged refractory surfaces with different composition of aggregate were used in corrosion tests. Performance of refractory coatings was evaluated by analysing the microstructure of the treated composites as well as mechanical properties. Energy-dispersive X-ray spectroscopy (SEM/EDS and optical microscopy were used to study the microstructure in the corroded region of the refractory coatings. Long term studies in the solution of 1M K2CO3 for 56 months have demonstrated that composite with the additive of fluid cracking catalyst of oil refinery and petrochemical industries is more durable in the potassium rich environment.DOI: http://dx.doi.org/10.5755/j01.ms.22.3.8348

  17. Biomechanical evaluation of different hydroxyapatite coatings on titanium for keratoprosthesis

    Science.gov (United States)

    Dong, Ying; Qiu, Zhiye; Liu, Xiaoyu; Wang, Liqiang; Yang, Jingxin; Huang, Yifei; Cui, Fuzhai

    2015-09-01

    Stable tissue integration is important to keratoprosthesis (KPro). The aim of this study was to evaluate the tissue bonding ability of hydroxyapatite (HAp)-coated titanium KPro. The samples were divided into three groups: test groups (IBAD group and AD group) and Ti control. The coated samples had a HAp layer created by ion beam assisted deposition (IBAD) or aerosol deposition (AD). The surface characteristics were analyzed with SEM, AFM, and XRD. The samples were surgically inserted into the muscles of rabbits. Eight weeks after healing, the attachment to the tissue was tested with a universal test device. The three samples exhibited distinctive surface morphology. The force to remove the HAp implants from the muscles was significantly greater than that of Ti group ( P < 0.01), with the AD samples requiring the greatest force ( P < 0.01). After removal, SEM showed that the tissue was firmly attached to the surface of AD samples. Photomicrographs of the peri-implant muscles showed a layer of aligned fibrous tissue without severe inflammation. The AD samples had more fibroblasts. Results indicate that because of enhanced mechanical adhesion of soft tissue to the implants, HAp-coated Ti by AD is a suitable KPro skirt material.

  18. Evaluation of hardness and color stability in the soft lining materials after thermocycling and chemical polishing.

    Science.gov (United States)

    Goiato, Marcelo Coelho; Falcón-Antenucci, Rosse Mary; Santos, Daniela Micheline dos; Pellizzer, Eduardo Piza

    2009-01-01

    The aim of this study was to evaluate the Shore A hardness and color stability of two soft lining materials after thermocycling and when chemical polishing was used or omitted. Two acrylic-based soft lining materials were tested: Coe-Soft and Soft Confort, 14 specimens were made for each material. They were distributed in four groups according to the treatment performed. The specimens were thermocycled (1000 cycles) and half of the group submitted to chemical polishing (methyl methacrylate). Shore A hardness was determined and color stability was calculated by means of Commission International de l'Eclairage Lab uniform color scale using a spectrophotometer, the measurements were made immediately after deflasked, chemical polishing and thermocycling. Analysis of variance (ANOVA) and Tukey's tests were performed at p Confort (10.60) showed significantly higher values than Coe-Soft (4.57). Coe-Soft (26.42) showed higher Shore A hardness values than Soft Confort (19.42). Chemical polishing did not influence in the color stability of both materials; however, influenced in the hardness values of Coe-Soft.

  19. Evaluation of quality indexes of bending performance and hardness for hardwoods

    OpenAIRE

    Teranishi, Masataka; KOIZUMI, Akio; Hirai, Takuro

    2008-01-01

    Mechanical properties of 613 small clear specimens of 35 species (11 ring-porous hardwoods, 19 diffuse-porous hardwoods, and 5 softwoods) were evaluated. The aim of the study was to discuss indexes of wood quality that are easy to measure and that exhibit a high correlation with bending performance and hardness that are essential properties of hardwood products. The modulus of rigidity, dynamic modulus of elasticity, bending properties (modulus of elasticity, modulus of rupture, stress at the...

  20. Quantitative Image Analysis for Evaluating the Coating Thickness and Pore Distribution in Coated Small Particles

    NARCIS (Netherlands)

    Laksmana, F L; Van Vliet, L J; Hartman Kok, P J A; Vromans, H; Frijlink, H W; Van der Voort Maarschalk, K

    This study aims to develop a characterization method for coating structure based on image analysis, which is particularly promising for the rational design of coated particles in the pharmaceutical industry. The method applies the MATLAB image processing toolbox to images of coated particles taken

  1. Quantitative Image Analysis for Evaluating the Coating Thickness and Pore Distribution in Coated Small Particles

    NARCIS (Netherlands)

    Laksmana, F.L.; Van Vliet, L.J.; Hartman Kok, P.J.A.; Vromans, H.; Frijlink, H.W.; Van der Voort Maarschalk, K.

    2008-01-01

    Purpose This study aims to develop a characterization method for coating structure based on image analysis, which is particularly promising for the rational design of coated particles in the pharmaceutical industry. Methods The method applies the MATLAB image processing toolbox to images of coated

  2. Detailed analysis of seed coat and cotyledon reveals molecular understanding of the hard-to-cook defect of common beans (Phaseolus vulgaris L.).

    Science.gov (United States)

    Yi, Jianyong; Njoroge, Daniel M; Sila, Daniel N; Kinyanjui, Peter K; Christiaens, Stefanie; Bi, Jinfeng; Hendrickx, Marc E

    2016-11-01

    The hard-to-cook (HTC) defect in legumes is characterized by the inability of cotyledons to soften during the cooking process. Changes in the non-starch polysaccharides of common bean seed coat and cotyledon were studied before and after development of the HTC defect induced by storage at 35°C and 75% humidity for 8months. Distinct differences in the yields of alcohol insoluble residues, degree of methoxylation (DM), sugar composition, and molar mass distribution of non-starch polysaccharides were found between the seeds coat and cotyledons. The non-starch polysaccharide profiles, both for seed coats and cotyledons, significantly differed when comparing HTC and easy-to-cook (ETC) beans. In conclusion, differences in the structure, composition and extractability of non-starch polysaccharides between the ETC and HTC beans confirmed the significant role of pectin polysaccharides in interaction with divalent ions in the HTC development, which consequently affect their cooking behaviors. Copyright © 2016 Elsevier Ltd. All rights reserved.

  3. Silica-Based and Borate-Based, Titania-Containing Bioactive Coatings Characterization: Critical Strain Energy Release Rate, Residual Stresses, Hardness, and Thermal Expansion

    Directory of Open Access Journals (Sweden)

    Omar Rodriguez

    2016-12-01

    Full Text Available Silica-based and borate-based glass series, with increasing amounts of TiO2 incorporated, are characterized in terms of their mechanical properties relevant to their use as metallic coating materials. It is observed that borate-based glasses exhibit CTE (Coefficient of Thermal Expansion closer to the substrate’s (Ti6Al4V CTE, translating into higher mode I critical strain energy release rates of glasses and compressive residual stresses and strains at the coating/substrate interface, outperforming the silica-based glasses counterparts. An increase in the content of TiO2 in the glasses results in an increase in the mode I critical strain energy release rate for both the bulk glass and for the coating/substrate system, proving that the addition of TiO2 to the glass structure enhances its toughness, while decreasing its bulk hardness. Borate-based glass BRT3, with 15 mol % TiO2 incorporated, exhibits superior properties overall compared to the other proposed glasses in this work, as well as 45S5 Bioglass® and Pyrex.

  4. Evaluation of critical process parameters for inter-tablet coating uniformity of active-coated GITS using Terahertz Pulsed Imaging.

    Science.gov (United States)

    Brock, Daniela; Zeitler, J Axel; Funke, Adrian; Knop, Klaus; Kleinebudde, Peter

    2014-10-01

    The aim of this study was the evaluation of critical process parameters (CPP) for inter-tablet coating uniformity in an active pan coating process using nondestructive Terahertz Pulsed Imaging (TPI). Coating uniformity was assessed by calculating the coefficient of variation (CV) of coating thickness measured by TPI, and the CV of API content measured by high performance liquid chromatography (HPLC). A design of experiments (DoE) was performed at pilot scale with drum load, drum speed, spray rate, run duration and spray pressure as factors. Good agreement in the CV of both analytical techniques was shown. The DoE models both revealed the same CPP: a low drum load, high drum speed, low spray rate and high run duration were beneficial for coating uniformity. The spray pressure was only significant in one of the DoE models. It was further shown that the negative impact of a high drum load on the CV cannot only be compensated by high drum speed, but also be compensated by a low spray rate and long run duration. It was demonstrated that TPI is a feasible tool for the measurement of inter-tablet coating uniformity and for the evaluation of CPP in an active pan coating process. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Evaluation of the mechanical properties of microarc oxidation coatings and 2024 aluminium alloy substrate

    CERN Document Server

    Xue Wen Bin; Deng Zhi Wei; Chen Ru Yi; Li Yong Liang; Zhang Ton Ghe

    2002-01-01

    A determination of the phase constituents of ceramic coatings produced on Al-Cu-Mg alloy by microarc discharge in alkaline solution was performed using x-ray diffraction. The profiles of the hardness, H, and elastic modulus, E, across the ceramic coating were determined by means of nanoindentation. In addition, a study of the influence of microarc oxidation coatings on the tensile properties of the aluminium alloy was also carried out. The results show that the H-and E-profiles are similar, and both of them exhibit a maximum value at the same depth of coating. The distribution of the alpha-Al sub 2 O sub 3 phase content determines the H- and E-profiles of the coatings. The tensile properties of 2024 aluminium alloy show less change after the alloy has undergone microarc discharge surface treatment.

  6. Evaluation of hydrogen-Induced cracking resistance of the In625 laser coating system on a C-Mn steel substrate

    Directory of Open Access Journals (Sweden)

    Vicente Braz Trindade

    Full Text Available Abstract The corrosion of C-Mn steels in the presence of hydrogen sulfide (H2S represents a significant challenge to oil production and natural gas treatment facilities. The failure mechanism induced by hydrogen-induced cracking (HIC in a Inconel 625 coating / C-Mn steel has not been extensively investigated in the past. In the present work, an API 5CT steel was coated with In625 alloy using laser cladding and the HIC resistance of different regions, such as the coating surface, the substrate and HAZ, were evaluated. SEM observations illustrated that all HIC cracks were formed at the hard HAZ after 96h of exposure. No HIC cracks were observed in the substrate and the In625 coating after the same exposure duration. Pitting was recorded in the substrate caused by non-metallic inclusion dissolving.

  7. Investigation of corrosion and wear mechanisms in hard material-reinforced duplex steel coatings; Untersuchungen zum Korrosions- und Verschleissverhalten von hartstoffverstaerkten `Duplex`-Schutzschichten. Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Bouaifi, B. [Technische Univ. Clausthal, Clausthal-Zellerfeld (Germany). Inst. fuer Schweisstechnik und Trennende Fertigungsverfahren; Goellner, J. [Technische Univ. Magdeburg (Germany). Inst. fuer Werkstofftechnik und Werkstoffpruefung

    1998-09-30

    The hard-material reinforced duplex steel coatings were deposited by plasma arc two-powder surfacing. By varying the angle of the hard materials feeding process, the deposition of the carbides was optimized so that they are deposited into the matrix in the trailing zone of the welding torch under conditions of very low thermal effects near the freezing point of the weld pool. Microstructural studies revealed that the deposition of the hard materials prevents devlopment of the typical, ferritic-austenitic microstructure of duplex steels. Due to a dissolution and diffusion process, the microstructure of the matrix takes up carbon and chromium or tungsten, depending on the carbide, thus enhancing the austenitic material in the microstructure. The wear behaviour of the surface deposits was found to be very good, wear being reduced by a factor of 6, irrespective of the type of carbide. The friction-affected surfaces showed no dissolving effects or cracking. The corrosion behaviour in sulfuric acid is also good. The welded deposits exhibited the typical behaviour of a passive material. Wear mechanisms slightly reduce the resistance. The behaviour of various specimens in artificial seawater could be distinctly assessed. Small grain fractions and pre-heating temperatures of 100 C have a beneficial effect on the corrosion resistance. The technique recommends itself for applications such as coatings for baffle plates used in flue gas desulfurisation, pipes, pump components, flanges or nozzles, or for recurrent coating of system components affected by abrasive corrosion. (orig./CB) [Deutsch] Zur Herstellung hartstoffverstaerkter Duplex-Beschichtungen wurde das Plasma-Zwei-Pulver-Auftragschweissverfahren verwendet. Hierbei wurde durch Variation des Zufuhrwinkels der Hartstoffe der Einbringungsort der Karbide optimiert, so dass diese im Nachlauf des Schweissbrenners mit sehr geringer thermischer Beeinflussung im erstarrungsnahen Schmelzbadbereich in die Matrix eingelagert

  8. Soft versus hard nanoparticles in the delivery of aromatic ...

    African Journals Online (AJOL)

    McRoy

    coated hard nanoparticles). E) Nanoparticles with compact core covered by a porous material with the photosensitisers covalently bonded (hybrid nanoparticles and silica-coated hard nanoparticles). The first attempt to target hard nanoparticles.

  9. Evaluation of nanohydroxyapaptite (nano-HA) coated epigallocatechin-3-gallate (EGCG) cross-linked collagen membranes.

    Science.gov (United States)

    Chu, Chenyu; Deng, Jia; Man, Yi; Qu, Yili

    2017-09-01

    Collagen is the main component of extracellular matrix (ECM) with desirable biological activities and low antigenicity. Collagen materials have been widely utilized in guided bone regeneration (GBR) surgery due to its abilities to maintain space for hard tissue growth. However, pure collagen lacks optimal mechanical properties. In our previous study, epigallocatechin-3-gallate (EGCG) cross-linked collagen membranes, with better biological activities and enhanced mechanical properties, may promote osteoblast proliferation, but their effect on osteoblast differentiation is not very significant. Nanohydroxyapatite (nano-HA) is the main component of mineral bone, which possesses exceptional bioactivity properties including good biocompatibility, high osteoconductivity and osteoinductivity, non-immunogenicity and non-inflammatory behavior. Herein, by analyzing the physical and chemical properties as well as the effects on promoting bone regeneration, we have attempted to present a novel EGCG-modified collagen membrane with nano-HA coating, and have found evidence that the novel collagen membrane may promote bone regeneration with a better surface morphology, without destroying collagen backbone. To evaluate the surface morphologies, chemical and mechanical properties of pure collagen membranes, epigallocatechin-3-gallate (EGCG) cross-linked collagen membranes, nano-HA coated collagen membranes, nano-HA coated EGCG-collagen membranes, (ii) to evaluate the bone regeneration promoted by theses membranes. In the present study, collagen membranes were divided into 4 groups: (1) untreated collagen membranes (2) EGCG cross-linked collagen membranes (3) nano-HA modified collagen membranes (4) nano-HA modified EGCG-collagen membranes. Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to evaluate surface morphologies and chemical properties, respectively. Mechanical properties were determined by differential scanning calorimeter (DSC

  10. Experimental Researches Tribological Properties of Hard-Alloy Blades With a Vacuum-Plasma Coating in the Chipboards Milling Process

    Directory of Open Access Journals (Sweden)

    Pavel Viktorovič Rudak

    2015-01-01

    Full Text Available While developing effective ion-plasma coatings compositions of woodcutting tools special conditions of its use should be taken into account particularly the force rate acting on the cutting wedge. With the penetration of the blade into the wood material normal pressure and friction appear on the connection surface. For the analysis of the cutting processes the connection surface can be divided into several zones. The cutters with vacuum-plasma coatings based on TiN are characterized by a lower coefficient of friction in comparison to uncoated cutters in real conditions. The developed technique of tribotechnical tool tests of milling woodchip board is of great importance to establish the regularities of chip formation, chips movement and dust in the timber cutting areas as well as wood materials at milling in a wide parameter range of cutting conditions, for the development of methods and devices of chips and dust suppression.

  11. Validation of HVOF Thermal Spray Coatings as a Replacement for Hard Chrome Plating on Hydraulic/Pneumatic Actuators

    Science.gov (United States)

    2007-12-01

    installed on a six-axis robot arm in a sound-proof booth, programmed and operated remotely. Most depots already use this type of booth for their...powder feeders are commonly used to permit changeover from one coating to another without interrupting the spraying. • 6-axis industrial robot and...booths with the air handler in the background, the robot on which the spray gun in mounted directly in front, and the powder feeder at the left

  12. Deposition and characterisation of multilayer hard coatings. Ti/TiN delta/TiC sub x N sub y /(TiC) a-C H/(Ti) a-C H

    CERN Document Server

    Burinprakhon, T

    2001-01-01

    mixture. The top layer (Ti) a-C:H was found to contain approximately 10 atomic % nitrogen, due to N sub 2 contamination during deposition caused by low conductance of N sub 2 through the nominally closed valve of the mass flow controller. The change of the CH sub 4 concentration during deposition of the top layer (Ti) a-C:H, however, showed a strong influence on the hydrogen content. The comparison of the fluorescence background of the Raman spectra revealed that hydrogen-less (Ti) a-C:H was deposited at a CH sub 4 concentration of less than 50 % flow rate in Ar. The hardness and adhesion of the multilayer coated titanium substrates were assessed by using microindentation hardness and scratch tests, respectively. A simple hardness model containing parameters that assess the contributions from the coating and the substrate to the measured hardness was developed to describe hardness variation as a function of indentation size. This model allowed the determination of a coating hardness and an effective substrate...

  13. A field evaluation of coated urea with biodegradable materials and ...

    African Journals Online (AJOL)

    ajl yemi

    2011-12-28

    Dec 28, 2011 ... urea), UAGCu (agar + Cu + urea), UGCu (gelatine + Cu coated urea), UCu (Cu coated urea) and UCuZn (Cu + Zn coated urea), which were surface applied once at the start of the experiment after clearing previously grown grass and irrigating the plot site. The plot was never fertilized for the last five years.

  14. Evaluation of hardness and surface roughness of two maxillofacial silicones following disinfection

    Directory of Open Access Journals (Sweden)

    Marcelo Coelho Goiato

    2009-03-01

    Full Text Available The purpose of this study was to evaluate the Shore A hardness and surface roughness of two silicones for maxillofacial prosthetic treatment, under the influence of chemical disinfection and storage. Twenty-eight specimens were obtained, half of which were made of Silastic MDX 4-4210 silicone and, the other half were made of Silastic 732 RTV silicone. The specimens were divided into four groups: Silastic 732 RTV and MDX 4-4210 with disinfection 3 times a week with Efferdent tablets and the same materials without disinfection. The hardness of the materials was analyzed with a Shore A Durometer. The surface roughness was established by a digital portable roughness tester, initially and 2 months after the confection of the specimens. A variance test was applied (2-way ANOVA, followed by Tukey test (the level of significance was set at 1%. The storage time factor statistically influenced (p < 0.01 the materials' properties of hardness and roughness. MDX 4-4210 (28.59 Shore A, 0.789 Ra presented higher values than Silastic 732 RTV (18.08 Shore A, 0.656 Ra for both properties. Regarding the disinfection period, there was no significant difference in any of the materials tested.

  15. Effects of hard chrome and MoN-coated stainless steel on wear behaviour and tool life model under two-body abrasion wear testing

    Directory of Open Access Journals (Sweden)

    P. Srisattayakul

    2017-01-01

    Full Text Available The objectives of this study were to investigate the effect of the electroplated hard chrome (HC and the MoNcoated AISI 316 stainless steel coatings on weight loss under two-body abrasion wear testing and to predict the tool life of both materials used as a fishing net-weaving machine component, namely the hook. Both materials were used to carry out the wear experiments under two-body abrasion behavior. These specimens were wear tested with the in-house wear testing apparatus base on ASTM: G133-05 standard. The Taylor’s equation was used to formulate the tool life model whereas the Monte Carlo simulation was used to predict the tool life of the machine part. The results showed that the MoN-HC exhibited higher wear resistance than that of the HC.

  16. Evaluation of Erosion Resistance of Advanced Turbine Thermal Barrier Coatings

    Science.gov (United States)

    Zhu, Dongming; Kuczmarski, Maria A.; Miller, Robert A.; Cuy, Michael D.

    2007-01-01

    The erosion resistant turbine thermal barrier coating system is critical to aircraft engine performance and durability. By demonstrating advanced turbine material testing capabilities, we will be able to facilitate the critical turbine coating and subcomponent development and help establish advanced erosion-resistant turbine airfoil thermal barrier coatings design tools. The objective of this work is to determine erosion resistance of advanced thermal barrier coating systems under simulated engine erosion and/or thermal gradient environments, validating advanced turbine airfoil thermal barrier coating systems based on nano-tetragonal phase toughening design approaches.

  17. Hearing, Deaf, and Hard-of-Hearing Israeli Adolescents' Evaluations of Deaf Men and Deaf Women's Occupational Competence

    National Research Council Canada - National Science Library

    Amatzia Weisel; Rachel Gali Cinamon

    2005-01-01

    This study examined 74 deaf and hard-of-hearing (D/HH) and 91 hearing high school students regarding their own occupational aspirations and their evaluations of occupational competence (EOCs) for deaf adults...

  18. Effect of exercise-induced muscle damage on muscle hardness evaluated by ultrasound real-time tissue elastography

    OpenAIRE

    Yanagisawa, Osamu; Sakuma, Jun; Kawakami, Yasuo; Suzuki, Katsuhiko; Fukubayashi, Toru

    2015-01-01

    Purpose To assess the effect of exercise-induced muscle damage on muscle hardness and evaluate the relationship between muscle hardness and muscle damage indicators. Methods Seven men (mean 25.3?years; 172.7?cm; 66.8?kg) performed the single-leg ankle plantar flexion exercise involving both concentric and eccentric contractions (10 sets of 40 repetitions). The hardness of the medial gastrocnemius (MG) was evaluated using ultrasound real-time tissue elastography before, from day 1 to 4, and da...

  19. A novel hohlraum with ultrathin depleted-uranium-nitride coating layer for low hard x-ray emission and high radiation temperature

    CERN Document Server

    Guo, Liang; Xing, Peifeng; Li, Sanwei; Yi, Taimin; Kuang, Longyu; Li, Zhichao; Li, Renguo; Wu, Zheqing; Jing, Longfei; Zhang, Wenhai; Zhan, Xiayu; Yang, Dong; Jiang, Bobi; Yang, Jiamin; Liu, Shenye; Jiang, Shaoen; Li, Yongsheng; Liu, Jie; Huo, Wenyi; Lan, Ke

    2014-01-01

    An ultra-thin layer of uranium nitrides (UN) has been coated on the inner surface of the depleted uranium hohlraum (DUH), which has been proved by our experiment can prevent the oxidization of Uranium (U) effectively. Comparative experiments between the novel depleted uranium hohlraum and pure golden (Au) hohlraum are implemented on Shenguang III prototype laser facility. Under the laser intensity of 6*10^14 W/cm2, we observe that, the hard x-ray (> 1.8 keV) fraction of this uranium hohlraum decreases by 61% and the peak intensity of total x-ray flux (0.1 keV ~ 5 keV) increases by 5%. Two dimensional radiation hydrodynamic code LARED are exploited to interpret the above observations. Our result for the first time indicates the advantage of the UN-coated DUH in generating the uniform x-ray field with a quasi Planckian spectrum and thus has important implications in optimizing the ignition hohlraum design.

  20. In vitro evaluation of paclitaxel coatings for delivery via drug-coated balloons.

    Science.gov (United States)

    Kempin, Wiebke; Kaule, Sebastian; Reske, Thomas; Grabow, Niels; Petersen, Svea; Nagel, Stefan; Schmitz, Klaus-Peter; Weitschies, Werner; Seidlitz, Anne

    2015-10-01

    Lately, drug-coated balloons have been introduced in interventional cardiology as an approach to treat occluded blood vessel. They were developed for the rapid transfer of antiproliferative drugs during the angioplasty procedure in stenosed vessels with the intent to reduce the risk of restenosis. In this study five different paclitaxel (PTX) balloon coatings were tested in vitro in order to examine how solvents and additives influence coating stability and drug transfer rates. PTX-coated balloons were advanced through a guiding catheter and a simulated coronary artery pathway under perfusion and were then inflated in a hydrogel acceptor compartment. The fractions transferred to the gel, remaining on the balloon and the PTX lost in the simulated coronary pathway were then analysed. The results obtained suggest that the solvent used for the coating process strongly influences the surface structure and the stability of the coating. Ethanol/water and acetone based PTX coatings showed the lowest drug transfer rates to the simulated vessel wall (both coated with PTX from ethyl acetate-solutions showed smaller drug loss (83%±9%), but most of the remaining PTX was not transferred (mean balloon residue approximately 15%). Beside the solvent, the use of additives seemed to have a great impact on transfer properties. The balloon pre-treatment with a crosslinked polyvinylpyrrolidone (PVP) film was able to increase the PTX transfer rate from less than 1% (without PVP) to approximately 6%. The best results in this study were obtained for balloon coatings with commercially available SeQuent© Please balloons containing the contrast agent iopromide. For this formulation drug transfer rates of approximately 17% were determined. Fluorescence microscopic imaging could visualize the particulate transfer of labelled PTX from the balloon surface during dilatation. The findings of this study underline the importance of drug adhesion and coating stability for the efficiency of PTX

  1. Fracture evaluation of thermally sprayed coatings in dependence on cohesive strength

    Science.gov (United States)

    Schubert, J.; Česánek, Z.

    2017-05-01

    Measuring the cohesive strength of thermally sprayed coatings is relatively difficult matter, which can be accessed in many directions. This issue is nowadays solved by use of Scratch test method. This method is not completely sufficient for the cohesive strength testing because the coating is under load of combined stresses during the Scratch test. The reason to develop this method was need for exact measurement of tensile cohesion toughness of thermally sprayed coatings, which could provide results as close to a classic tensile test as possible. Another reason for development of this method was the impossibility of direct comparison with results obtained by other methods. Tested coatings were prepared using HP / HVOF (Stellite 6, NiCrBSi, CrC-NiCr and Hastelloy C-276). These coatings were selected as commonly used in commercial sector and also on because of rising customer demand for ability to provide such coating characteristics. The tested coatings were evaluated in terms of cohesive strength (method based on tensile strength test). Final fractures were evaluated by optical microscopy together with scanning electron microscopy and EDS analysis. As expected higher cohesive strength showed metallic coatings with top results of coating Stellite 6. Carbide coatings showed approximately third of the cohesion strength in comparison with metal based coating.

  2. Evaluation of human muscle hardness after dynamic exercise with ultrasound real-time tissue elastography: a feasibility study.

    Science.gov (United States)

    Yanagisawa, O; Niitsu, M; Kurihara, T; Fukubayashi, T

    2011-09-01

    To assess the feasibility of ultrasound real-time tissue elastography (RTE) for measuring exercise-induced changes in muscle hardness and to compare the findings of RTE with those of a tissue hardness meter for semi-quantitative assessment of the hardness of exercised muscles. Nine male participants performed an arm-curl exercise. RTE measurements were performed by manually applying repetitive compression with the transducer on the scan position before exercise, immediately after exercise, and at 30 min after exercise; strain ratios between muscle and a reference material (hydrogel) were calculated (muscle strain/material strain). A tissue hardness meter was also used to evaluate muscle hardness. The intraclass correlation coefficients (ICCs) for the three repeated measurements at each measurement time were calculated to evaluate the intra-observer reproducibility of each technique. Immediately after exercise, the strain ratio and the value obtained using the tissue hardness meter significantly decreased (from 1.65 to 1.35) and increased (from 51.8 to 54.3), respectively. Both parameters returned to their pre-exercise value 30 min after exercise. The ICCs of the RTE (and the ICCs of the muscle hardness meter) were 0.971 (0.816) before exercise, 0.939 (0.776) immediately after exercise, and 0.959 (0.882) at 30 min after exercise. Similar to the muscle hardness meter, RTE revealed the exercise-induced changes of muscle hardness semi-quantitatively. The intra-observer reproducibility of RTE was very high at each measurement time. These findings suggest that RTE is a clinically useful technique for assessing hardness of specific exercised muscles. Copyright © 2011 The Royal College of Radiologists. Published by Elsevier Ltd. All rights reserved.

  3. Evaluating the Effect of Hardness on Erosion Characteristics of Aluminum and Steels

    Science.gov (United States)

    Malik, J.; Toor, I. H.; Ahmed, W. H.; Gasem, Z. M.; Habib, M. A.; Ben-Mansour, R.; Badr, H. M.

    2014-06-01

    In this paper, the erosion behavior of commonly used stainless steels (AISI 310S, AISI 316), carbon steel (AISI 1020), and Aluminum 6060 were experimentally investigated. The effect of hardness on erosion rates and on the morphologies of eroded surfaces has been evaluated. The experiments were carried out using an air jet erosion tester and utilizing angular alumina as erodent with 50 µm particle size. The samples were tested at six different impact angles (15°, 30°, 45°, 60°, 75°, and 90°) using three different impact velocities (30, 60, and 100 m/s). The eroded surfaces were analyzed using a scanning electron microscope (SEM) for the evaluation of material degradation. The erosion rates were found to increase with the increase of the alloy bulk hardness and Aluminum 6060 showed maximum erosion resistance. For all specimens, the erosion rates were found to increase with the increase of impact velocity and the maximum erosion rate was found to occur between 15° and 30° impact angles. The obtained results were found to correlate very well with Oka et al. (Wear, 259:95-101, 2005) erosion model.

  4. Evaluation of metallized paint coatings for composite spacecraft structures

    Science.gov (United States)

    Brzuskiewicz, John E.

    1990-01-01

    The extreme temperature excursions of composite spacecraft structures in LEO must be minimized through the use of thermal-control coatings. Attention is presently given to tests of silicone resin coatings which were pigmented with either leafing aluminum or combinations of leafing aluminum with silicate-treated zinc oxide pigment. Atomic oxygen, UV/vacuum, and outgassing screening tests were conducted on several such coating formulations in order to characterize the performance characteristics of this coating concept. Performance was found to depend on pigment volume concentration.

  5. EVALUATION OF OPERATIONAL EFFICIENCY OF DIFFUSION COATINGS FOR TURBINE BLADES OF CONTEMPORARY GAS TURBINE ENGINES

    Directory of Open Access Journals (Sweden)

    E. G. Ivanov

    2014-01-01

    Full Text Available The article considers the comparative evaluation of the heat resistant diffusion coatings durability in their further work as part of the engine based on the results of laboratory tests. For the purpose of comparative evaluation of the operational life the criterion of durability is introduced to allow estimate characteristics of various protective coatings without testing as part of the engine.

  6. In vitro evaluation of the impact of silver coating on Escherichia coli adherence to urinary catheters.

    Science.gov (United States)

    Ogilvie, Adam T; Brisson, Brigitte A; Singh, Ameet; Weese, J Scott

    2015-05-01

    A silver-coated urinary catheter was compared to a non-silver-coated urinary catheter for the ability to reduce adherence of 6 isolates of Escherichia coli. Catheters were incubated with E. coli strains for 0, 24, 48, and 72 h. Broth was sampled at all time points to determine CFU/mL. Catheters were subjected to sonication to determine adhered bacteria at all time points, and scanning electron microscopy (SEM) to semi-quantitatively assess biofilm formation. Silver-coated catheters had significantly less adhered bacteria than non-silver-coated catheters at times 24, 48, and 72 h. Subjectively, silver-coated urinary catheters had less biofilm formation than non-silver-coated urinary catheters as assessed by SEM. Silver coating of catheters was associated with reduced adherence of E. coli in an in vitro evaluation. Testing of catheters in dogs in vivo is required to determine if there is a reduction in catheter-associated urinary tract infections.

  7. THE STRUCTURE AND PROPERTIES OF COMPOSITE LASER CLAD COATINGS WITH Ni BASED MATRIX WITH WC PARTICLES

    Directory of Open Access Journals (Sweden)

    Zita Iždinská

    2010-09-01

    Full Text Available In this work, the influence of the processing conditions on the microstructure and abrasive wear behavior of composite laser clad coatings with Ni based matrix reinforced with 50% WC particles is analyzed. Composite powder was applied in the form of coatings onto a mild steel substrate (Fe–0.17% C by different laser powers and cladding speeds. The microstructure of the coatings was analyzed by scanning electron microscopy (SEM. Tribological properties of coatings were evaluated by pin-on-disc wear test. It appeared that the hardness of the matrix of composite coatings decreases with increasing cladding speed. However, wear resistance of composite coatings with decreasing hardness of Ni based matrix increases. Significantly enhanced wear resistance of WC composite coatings in comparison with Ni based coatings is attributed to the hard phase structures in composite coatings.

  8. Evaluation of high oleic-high stearic sunflower hard stearins for cocoa butter equivalent formulation.

    Science.gov (United States)

    Bootello, Miguel A; Hartel, Richard W; Garcés, Rafael; Martínez-Force, Enrique; Salas, Joaquín J

    2012-10-01

    Cocoa butter equivalents (CBEs) are produced from vegetable fats by blending palm mid fraction (PMF) and tropical butters coming from shea, mango kernel or kokum fat. In this regard, high oleic-high stearic (HOHS) sunflower hard stearins from solvent fractionation can be used in CBE production since their compositions and physical properties are similar to those found in the above-mentioned tropical butters. In this work, three sunflower hard stearins (SHS) ranging from 65% to 95% of disaturated triacylglycerols and a shea stearin (used as reference) were blended with PMF to evaluate their potential use in CBEs formulation. Isosolid phase diagrams of mixtures of PMF/SHS showed eutectic formation for SHS 65 and SHS 80, but monotectic behaviour with softening effect for SHS 95. Three CBEs from SHS and shea stearin were formulated according to phase behaviour diagrams and solid fat content data at 25 °C. Isosolid phase diagrams of mixtures of these CBEs with cocoa butter showed no eutectic behaviour. Therefore, CBEs elaborated from SHS exhibited full compatibility with cocoa butter. Copyright © 2012 Elsevier Ltd. All rights reserved.

  9. Evaluation of Vickers hardness of different types of acrylic denture base resins with and without glass fibre reinforcement.

    Science.gov (United States)

    Farina, Ana Paula; Cecchin, Doglas; Soares, Rodrigo Gonçalves; Botelho, André Luís; Takahashi, Jessica Mie Ferreira Koyama; Mazzetto, Marcelo Oliveira; Mesquita, Marcelo Ferraz

    2012-06-01

    To evaluate the Vickers hardness of different acrylic resins for denture bases with and without the addition of glass fibres. It has been suggested that different polymerisation methods, as well as the addition of glass fibre (FV) might improve the hardness of acrylic. Five types of acrylic resin were tested: Vipi Wave (VW), microwave polymerisation; Vipi Flash (VF), auto-polymerisation; Lucitone (LT), QC20 (QC) and Vipi Cril (VC), conventional heat-polymerisation, all with or without glass fibre reinforcement (GFR) and distributed into 10 groups (n = 12). Specimens were then submitted to Vickers hardness testing with a 25-g load for 30 s. All data were submitted to anova and Tukey's HSD test. A significant statistical difference was observed with regard to the polymerisation method and the GFR (p hardness values, and VF and LT presented the lowest. In the presence of GFR, VC resin still presented the highest Vickers hardness values, and VF and QC presented the lowest. The acrylic resin VC and VW presented higher hardness values than VF and QC resins. Moreover, GFR increased the Vickers hardness of resins VW, VC and LT. © 2010 The Gerodontology Society and John Wiley & Sons A/S.

  10. Synthesis and Evaluation of Poly(3,4-ethylenedioxythiophene) (PEDOT) Coated Magnesium for Nerve Regeneration

    Science.gov (United States)

    Sebaa, Meriam Amel

    In an attempt to develop conductive, biodegradable, mechanically strong, and biocompatible nerve conduits, pure magnesium (Mg) was used as the biodegradable substrate material to provide strength while the conductive polymer, poly(3,4ethylenedioxythiophene) (PEDOT) was used as a conductive coating material to control Mg degradation and improve cytocompatibility of Mg substrates. A series of electrochemical deposition conditions were explored to produce a uniform, consistent PEDOT coating on Mg substrates. Five cycles of CV with the potential ranging from -0.5V to 2.0V were used to produce consistent coatings for further evaluation. Scanning electron micrographs showed the micro-porous structure of PEDOT coatings. Energy Dispersive X-ray Spectroscopy (EDS) showed the peaks of sulfur, oxygen, and carbon, indicating PEDOT coating. Adhesion strength of the coating was measured using ASTM-D 3359 standard tape test. The adhesion strength of PEDOT coating was within the classifications of 3B to 4B. Tafel tests of the PEDOT coated Mg showed a corrosion current (ICORR) of 6.14e-5A and critical voltage of -1.10V, as compared with ICORR of 9.08e-4A with a critical voltage of -1.35V for non-coated Mg. The calculated corrosion rate for the PEDOT coated Mg was 8.6 mm/year, much slower than 126.9mm/year for the non-coated Mg. H9 human embryonic stem cell (hESC) culture studies were conducted using magnesium (Mg) coated with a conductive polymer poly (3,4-ethylenedioxythiophene) (PEDOT) to study viability for potential neural applications. Stem cells cultured indirectly with the Mg coated with PEDOT for 2 cycles were viable for a about half the amount of time when compared with the stem cells cultured with the 5 cycle PEDOT coated Mg.

  11. Nanoparticle-coated organic-inorganic microparticles: experimental design and gastrointestinal tolerance evaluation

    Directory of Open Access Journals (Sweden)

    Ruy Carlos R. Beck

    2006-10-01

    Full Text Available The influences of the spray-drying parameters and the type of nanoparticles (nanocapsules or nanospheres on the characteristics of nanoparticle-coated diclofenac-loaded microparticles were investigated by using a factorial design 3². Gastrointestinal tolerance following oral administration in rats was evaluated. Formulations were selected considering the best yields, the best encapsulation efficiencies and the lowest water contents, presenting surfaces completely coated by nanostructures and a decrease in the surface areas in relation to the uncoated core. In vitro drug release demonstrated the influence of the nanoparticle-coating on the dissolution profiles of diclofenac. Nanocapsule-coated microparticles presented a protective effect on the gastrointestinal mucosa.

  12. Nanoparticle-coated organic-inorganic microparticles: experimental design and gastrointestinal tolerance evaluation

    Directory of Open Access Journals (Sweden)

    Beck Ruy Carlos R.

    2006-01-01

    Full Text Available The influences of the spray-drying parameters and the type of nanoparticles (nanocapsules or nanospheres on the characteristics of nanoparticle-coated diclofenac-loaded microparticles were investigated by using a factorial design 3². Gastrointestinal tolerance following oral administration in rats was evaluated. Formulations were selected considering the best yields, the best encapsulation efficiencies and the lowest water contents, presenting surfaces completely coated by nanostructures and a decrease in the surface areas in relation to the uncoated core. In vitro drug release demonstrated the influence of the nanoparticle-coating on the dissolution profiles of diclofenac. Nanocapsule-coated microparticles presented a protective effect on the gastrointestinal mucosa.

  13. Evaluations of Strength of Thermal Sprayed Coating for Complex Loading

    Science.gov (United States)

    Kaneko, Kenji; Ohmori, Akira

    Fracture strength of WC-12Co thermal sprayed coating is investigated experimentally and analytically. In the experiments, one pair of butt cylindrical specimen with coating is subjected to combined tension with torsion stresses. Fracture loci were obtained for three kinds of thickness of the coating in σ-τ stress plane. Stress distributions at crack tip singular point on fractured surfaces are analyzed by Finite-Element-Method and approximated by the expression σ=KR-λ where R means normalized thickness coordinate. It is found that the normal stress distributions are common to all cases of testing stress conditions and so fracture condition of the brittle coating is represented as K≥Kcr in the normal stress distribution even under mixed deformation mode I and III. The delamination critical shear stress distribution could also be obtained.

  14. Electrochemical Evaluation of Corrosion Inhibiting Layers Formed in a Defect from Lithium-Leaching Organic Coatings

    NARCIS (Netherlands)

    Visser, P.; Meeusen, M.; Gonzalez Garcia, Y.; Terryn, H.A.; Mol, J.M.C.

    2017-01-01

    This work presents the electrochemical evaluation of protective layers generated in a coating defect from lithium-leaching organic coatings on AA2024-T3 aluminum alloys as a function of neutral salt spray exposure time. Electrochemical impedance spectroscopy was used to study the electrochemical

  15. A Technique for Standardized Evaluation of Soft and Hard Peri-Implant Tissues in Partially Edentulous Patients

    NARCIS (Netherlands)

    Meijndert, Leo; Meijer, Henny J.A.; Raghoebar, Gerry M.; Vissink, Arjan

    Background: There is a growing need to evaluate the esthetics of implant-supported crowns and bridges. An important tool for such an evaluation is standardized assessment of the soft and hard peri-implant tissue levels. Methods: A simple acrylic device has been developed for reliable and

  16. Objective and subjective hardness of a test item used for evaluating food mixing ability.

    Science.gov (United States)

    Salleh, N M; Fueki, K; Garrett, N R; Ohyama, T

    2007-03-01

    The aim of this study was to compare objective and subjective hardness of selected common foods with a wax cube used as a test item in a mixing ability test. Objective hardness was determined for 11 foods (cream cheese, boiled fish paste, boiled beef, apple, raw carrot, peanut, soft/hard rice cracker, jelly, plain chocolate and chewing gum) and the wax cube. Peak force (N) to compress each item was obtained from force-time curves generated with the Tensipresser. Perceived hardness ratings of each item were made by 30 dentate subjects (mean age 26.9 years) using a visual analogue scale (100 mm). These subjective assessments were given twice with a 1 week interval. High intraclass correlation coefficients (ICCs) for test-retest reliability were seen for all foods (ICC > 0.68; P < 0.001). One-way anova found a significant effect of food type on both the objective hardness score and the subjective hardness rating (P < 0.001). The wax cube showed significant lower objective hardness score (32.6 N) and subjective hardness rating (47.7) than peanut (45.3 N, 63.5) and raw carrot (82.5 N, 78.4) [P < 0.05; Ryan-Einot-Gabriel-Welsch (REGW)-F]. A significant semilogarithmic relationship was found between the logarithm of objective hardness scores and subjective hardness ratings across twelve test items (r = 0.90; P < 0.001). These results suggest the wax cube has a softer texture compared with test foods traditionally used for masticatory performance test, such as peanut and raw carrot. The hardness of the wax cube could be modified to simulate a range of test foods by changing mixture ratio of soft and hard paraffin wax.

  17. Evaluation of coat uniformity and taste-masking efficiency of irregular-shaped drug particles coated in a modified tangential spray fluidized bed processor.

    Science.gov (United States)

    Xu, Min; Heng, Paul Wan Sia; Liew, Celine Valeria

    2015-01-01

    To explore the feasibility of coating irregular-shaped drug particles in a modified tangential spray fluidized bed processor (FS processor) and evaluate the coated particles for their coat uniformity and taste-masking efficiency. Paracetamol particles were coated to 20%, w/w weight gain using a taste-masking polymer insoluble in neutral and basic pH but soluble in acidic pH. In-process samples (5, 10 and 15%, w/w coat) and the resultant coated particles (20%, w/w coat) were collected to monitor the changes in their physicochemical attributes. After coating to 20%, w/w coat weight gain, the usable yield was 81% with minimal agglomeration (dissolution in simulated gastric pH. The FS processor shows promise for direct coating of irregular-shaped drug particles with wide size distribution. The coated particles with 15% coat were sufficiently taste masked and could be useful for further application in orally disintegrating tablet platforms.

  18. Effect of exercise-induced muscle damage on muscle hardness evaluated by ultrasound real-time tissue elastography.

    Science.gov (United States)

    Yanagisawa, Osamu; Sakuma, Jun; Kawakami, Yasuo; Suzuki, Katsuhiko; Fukubayashi, Toru

    2015-01-01

    To assess the effect of exercise-induced muscle damage on muscle hardness and evaluate the relationship between muscle hardness and muscle damage indicators. Seven men (mean 25.3 years; 172.7 cm; 66.8 kg) performed the single-leg ankle plantar flexion exercise involving both concentric and eccentric contractions (10 sets of 40 repetitions). The hardness of the medial gastrocnemius (MG) was evaluated using ultrasound real-time tissue elastography before, from day 1 to 4, and day 7 after exercise. The strain ratio between the MG and a reference material was calculated. Simultaneously, we evaluated the magnetic resonance T2 value (an index of edema) of the triceps surae, the ankle dorsiflexion range of motion (ROM), and calf muscle soreness. Serum creatine kinase activity was assessed before, 2 and 4 h, and from day 1 to 4 after exercise. The MG showed lower strain ratio, indicating increased muscle hardness, on day 4 post-exercise (P muscle soreness among the post-exercise time points was similar. The decreased strain ratio did not correlate with the increased T2, the decreased joint ROM or muscle soreness. Muscle hardness increased after strenuous resistance exercise, but the change was not related with muscle edema, decreased joint ROM, or muscle soreness resulting from muscle damage.

  19. Evaluation of colour and hardness changes of soft lining materials in food colorant solutions.

    Science.gov (United States)

    Canay, S; Hersek, N; Tulunoğlu, I; Uzun, G

    1999-10-01

    The aim of this study was to measure the colour stability and viscoelastic properties of three commercially available soft lining materials in vitro, by exposing them to 3% erythrosine, tartrazine and sunset yellow solutions. The colour changes were determined using a computer controlled spectrophotometer. The colour change of three soft lining materials--Molloplast B, Flexor and Coe Super Soft--were determined after 1, 3 and 6 months storage in three different food colorant solutions. The colour changes of Molloplast B was not noticeable. Only the initial colour value of Flexor was significantly different from the other time interval colour measurements. On the other hand, the colour difference of Coe Super Soft was found to be significantly different at all comparative time interval measurements (P<0.05). According to Shore A hardness values, Molloplast B had an initial hardness of 44 in all three solutions, and there was a slight increase after 6 months. Flexor had an initial hardness of 39, at the end of 6 months the hardness changed a little. Coe Super Soft was fairly hard after processing and Shore A hardness was initially 89 which increased to 95 later on. According to these results, only the hardness values of Coe Super Soft showed a statistically significant difference when compared using Wilcoxon signed rank test at the P<0.05 level. As a conclusion, silicon type soft lining material seems to be more resistant to colour change and hardness than the acrylic type soft liners.

  20. Evaluation of Sprayed Polyurethane Foam Roofing and Protective Coatings

    Science.gov (United States)

    1981-11-01

    lower tein- peratures than bitumen -based materials. Coatings investigated are listed in Tables I and 2 based on water vapor transmission properties...chalking. or the properties, and are easy to apply. Since they are water entire thickness may deteriorate by hydrolysis. Their emulsions , there is no

  1. Evaluation of light curing distance and mylar strips color on surface hardness of two different dental composite resins.

    Science.gov (United States)

    Mousavinasab, Seyed Mostafa; Barekatain, Mehrdad; Sadeghi, Elahe; Nourbakhshian, Farzaneh; Davoudi, Amin

    2014-01-01

    Hardness is one of the basic properties of dental materials, specially composite resins which is relevant to their polymerization. The aim of this study was to evaluate the effect of light curing distance and the color of clear Mylar strips on surface hardness of Silorane-based (SCR) and Methacrylate-based composite resins (MCR). 40 samples of MCRs (Filtek Z250) and SCRs (Filtek P90) were prepared in size of 5 mm×2 mm (80 samples in total). The samples divided into 8 groups (10 samples in each one) based on the color of clear Mylar strips (white or blue) and distance from light curing source (0 mm or 2 mm). All the samples cured for 40 second and stored in incubator for 24 hours in 37°C temperature. Surface hardness test was done by Vickers test machine and the collected data were analyzed by one-way ANOVA and paired T-test by using SPSS software version 13 at significant level of 0.05. MCRs cured with blue Mylar strips from 0 mm distance had the highest (114.5 kg/mm(2)) and SCRs cured with white Mylar strips from 2 mm distance had the lowest (42.2 kg/mm(2)) mean of surface hardness. Also, the results of comparison among SCRs and MCRs showed significant differences among all groups (all P values <0.01). The hardness decreased as the distance increased and the blue Mylar strips provided higher hardness than clear ones. Also, Filtek Z250 showed higher hardness compared to Filtek P90.

  2. Histological and clinical evaluation of the hard palate mucous membrane graft for treatment of lower eyelid retraction

    DEFF Research Database (Denmark)

    Larsen, Sofie D H; Heegaard, Steffen; Toft, Peter B

    2017-01-01

    PURPOSE: To evaluate the histological appearances of the epithelial cells and the clinical effect of the hard palate mucous membrane (HPM) graft for the treatment of lower eyelid retraction (LER). METHODS: This was a follow-up study involving 15 patients, with a total of 16 eyes operated. Five...... diameter. RESULTS: Median follow-up time was 21.2 [range 4.5-87.9] months. Imprints from the graft and the hard palate showed equally large epithelial cells; imprints from conjunctiva showed small epithelial cells. The mean (±SD) scleral show was 0.12 ± 0.09 cornea diameter before surgery and 0.0003 ± 0...

  3. Automated pharmaceutical tablet coating layer evaluation of optical coherence tomography images

    Science.gov (United States)

    Markl, Daniel; Hannesschläger, Günther; Sacher, Stephan; Leitner, Michael; Khinast, Johannes G.; Buchsbaum, Andreas

    2015-03-01

    Film coating of pharmaceutical tablets is often applied to influence the drug release behaviour. The coating characteristics such as thickness and uniformity are critical quality parameters, which need to be precisely controlled. Optical coherence tomography (OCT) shows not only high potential for off-line quality control of film-coated tablets but also for in-line monitoring of coating processes. However, an in-line quality control tool must be able to determine coating thickness measurements automatically and in real-time. This study proposes an automatic thickness evaluation algorithm for bi-convex tables, which provides about 1000 thickness measurements within 1 s. Beside the segmentation of the coating layer, optical distortions due to refraction of the beam by the air/coating interface are corrected. Moreover, during in-line monitoring the tablets might be in oblique orientation, which needs to be considered in the algorithm design. Experiments were conducted where the tablet was rotated to specified angles. Manual and automatic thickness measurements were compared for varying coating thicknesses, angles of rotations, and beam displacements (i.e. lateral displacement between successive depth scans). The automatic thickness determination algorithm provides highly accurate results up to an angle of rotation of 30°. The computation time was reduced to 0.53 s for 700 thickness measurements by introducing feasibility constraints in the algorithm.

  4. Study on simple evaluation of mechanical properties of rock materials for Equotip hardness tester

    Science.gov (United States)

    Muramiya, Masaya; Yoshida, Hidenori; Tatsumi, Takakuni

    The mechanical properties of a rock or a soil are different in a narrow area. However, it is difficult to get their sample and to perform a various types of tests from the view points of time and economy. Thus, in this study, Equotip hardness test is focused. Because the test is easy to measure, it is possible to carry on the test at several points in a short time. Additionally, the cost performance of the test is excellent. In this article, the compression test for several artificial specimens is conducted, Equotip hardness test is also conducted before and after the compression test. Through the comparison between the measured data by the Equotip hardness test and the various properties, it turned out that the various properties can be presumed by Equotip hardness test.

  5. Simulation based Hardness Evaluation of a Multi-Objective Genetic Algorithm

    OpenAIRE

    Ansari, Shahab U.; Mansha, Sameen

    2014-01-01

    Studies have shown that multi-objective optimization problems are hard problems. Such problems either require longer time to converge to an optimum solution, or may not converge at all. Recently some researchers have claimed that real culprit for increasing the hardness of multi-objective problems are not the number of objectives themselves rather it is the increased size of solution set, incompatibility of solutions, and high probability of finding suboptimal solution due to increased number...

  6. Mechanical Properties of Stellite-6 coated AISI 316L Stainless Steel

    Directory of Open Access Journals (Sweden)

    Pushpinderjit Singh

    2016-01-01

    Full Text Available Present paper describes the mechanical properties of Stellite-6 coated AISI 316 L stainless steel. Specimens were coated using Detonation Gun thermal spray process, with different coating thicknesses of Stellite-6 ranging from 50 µm to 150 µm. Afterwards their properties like tensile strength, impact strength and micro hardness were evaluated on the basis of the results obtained from the experimentation. For comparison of substrate and coated material the graphs were plotted. The coated specimens exhibited superior impact strength and microhardness than that of the bare specimens, whereas the tensile strength of coated specimens decreased marginally with the increase in coating thickness.

  7. Evaluation of electrodeposited Mn-Co protective coatings on Crofer 22 APU steel

    DEFF Research Database (Denmark)

    Molin, Sebastian

    2017-01-01

    Interconnects used in Solid Oxide Cells stacks require protective coatings to lower their parabolic rate constant and block chromium evaporation (on the air side). In this work four different protective coatings on steel are evaluated for their high temperature corrosion resistance and electrical......-ray diffractomettry. Based on the results, influence of the Co/Mn ratio on the resulting corrosion properties are discussed. Parabolic rate constant of the coated samples is the lowest for the MnCo sample, whereas electrical resistance is the lowest for the Co sample, which has a corrosion rate similar to the not...

  8. Evaluation of edible polymer coatings enriched with green tea extract on quality of chicken nuggets

    Directory of Open Access Journals (Sweden)

    Prathyusha Kristam

    2016-07-01

    Full Text Available Aim: The present study was conducted to evaluate the physico-chemical and microbiological characteristics of chicken nuggets coated with sodium alginate (SA coatings at refrigerated (4±1°C and frozen (−18±1°C storage condition at regular periodic intervals. Materials and Methods: Chicken meat nuggets were separated into three groups: Uncoated control (C, coated with alginate coating (T1, and coated with alginate coating incorporated with 1% green tea extract (GTE (T2. The nuggets were analyzed at regular intervals of 5days for refrigerated storage and 15 days for frozen storage period in terms of pH, 2-thiobarbituric acid value (TBA, peroxide value (PV, total plate count (TPC, water loss, and sensory characteristics. Results: The results indicated that the nuggets coated with alginate-based coatings effectively reduced the spoilage as indicated by pH, TBA, and PVs. pH values of the formulations ranged from 6.15 to 6.34 at refrigerated storage temperature (4±1°C and 6.49-6.71 at frozen storage temperature (−18±1°C. TBA value of the treatments ranged from 1.28 to 1.54 mg MDA/kg and 1.34 to 1.50 mg MDA/kg under refrigerated and frozen storage temperatures, respectively. Color, flavor, juiciness, tenderness, and overall acceptability of the nuggets differed significantly (p<0.05 with the coated nuggets. The coated nuggets were well acceptable upto 15 days at refrigerated storage temperature (4±1°C and upto 75 days at frozen storage temperature (−18±1°C. Nuggets coated with GTE incorporated coating solution had a lower TBA-reactive substances values, PVs, and TPCs when compared to the nuggets coated with SA and the control group. Conclusion: Study revealed that incorporation of edible coatings with antioxidants, namely, GTE at 1% level had a significant effect in reducing the fat oxidation. The samples recorded a shelf life of 15 days under refrigerated storage when compared to their controls with 10 days of storage period and 75

  9. Comprehensive hard materials

    CERN Document Server

    2014-01-01

    Comprehensive Hard Materials deals with the production, uses and properties of the carbides, nitrides and borides of these metals and those of titanium, as well as tools of ceramics, the superhard boron nitrides and diamond and related compounds. Articles include the technologies of powder production (including their precursor materials), milling, granulation, cold and hot compaction, sintering, hot isostatic pressing, hot-pressing, injection moulding, as well as on the coating technologies for refractory metals, hard metals and hard materials. The characterization, testing, quality assurance and applications are also covered. Comprehensive Hard Materials provides meaningful insights on materials at the leading edge of technology. It aids continued research and development of these materials and as such it is a critical information resource to academics and industry professionals facing the technological challenges of the future. Hard materials operate at the leading edge of technology, and continued res...

  10. Evaluation of hardness and colour change of soft liners after accelerated ageing.

    Science.gov (United States)

    Mancuso, Daniela Nardi; Goiato, Marcelo Coelho; Zuccolotti, Bruna Carolina Rossatti; Moreno, Amália; dos Santos, Daniela Micheline

    2009-07-01

    Soft liners have been developed to offer comfort to denture wearers. However, this comfort is compromised when there is a change in the properties of the material, causing colour change, solubility, absorption and hardening. These characteristics can compromise the longevity of soft liners. The aim of this in vitro study was to investigate the effect of ageing on both the hardness and colour change of two soft liners following accelerated ageing. Two denture liners, one resin based (Trusoft, Bosworth, Illinois, USA) and one silicone based (Ufi Gel P, Voco GMBH, Cuxhaven, Germany), were tested in this study for both hardness (using the Shore A scale) and colour change (using the CIE L*a*b* colour scale), initially and after 1008 hours (6 weeks) of accelerated ageing. Statistical analysis was performed using the unpaired t-test with the Welch correction. These indicated that both materials increased in hardness and underwent colour change after accelerated ageing. The initial hardness of Trusoft was far lower than that of Ufi Gel P (18.2 Shore A units vs 34.8 Shore A units). However, for Trusoft the changes for both hardness (from 18.2 to 52.1 Shore A units) and colour change (16.85 on the CIE L*a*b* colour scale) were greater than those for Ufi Gel P, for which hardness changed from 34.8 to 36.5 Shore A units and the colour change was 5.19 on the CIE L*a*b* colour scale. Ufi Gel P underwent less hardness and colour change after accelerated ageing than Trusoft. On the other hand, the use of Trusoft may be preferable in cases where initial softness is a major consideration, such as when relining an immediate denture after implant surgery.

  11. Clinical Evaluations of Soft and Hard Tissue Repair Using Osteo Gen in Periodontal Intraosseous Defects

    Directory of Open Access Journals (Sweden)

    Haghighati F

    2000-05-01

    Full Text Available The aim of this study was to evaluate the repair of hard and soft tissue using Osteo Gen and"ncomparing with flap curettage in periodontal defects. 36 periodontal intraosseous defects in sixteen"npatients involved moderate to advanced periodontitis were randomly selected and allocated to two"ngroups: test (22 and control groups (14. Slow resorption, excellent tissue compatibility, no exfoliation"nand root resorption were considered during healing. The average of pocket depth in test and control"ngroups was 3.16 and 2.73 mm, respectively. After 6 months, the average of bone repair was 2.18 mm"n(68.97% and 0.46 mm (16.84% in test and control groups. Bone apposition was obtained in test group"n(0.09 mm (2.84% while bone loss observed in control group (0.32 mm(l 1.72%. Initial pocket depths"nin test and control groups were 7.68mm and 6.61mm. After six months, re-entry surgery was performed"nand the measurement of new attachment was 3.45 mm (61.19% and 2.81 mm (51.28%. Recession of"nthe gingival margin was 1.22 mm (15.80% and 0,58 mm (8.77% for test and control groups,"nrespectively. By considering these findings, using of Osteo Gen can be recommended compare with flap"ncurettage in periodontal intraosseous defects.

  12. Evaluation of multi-layered hardness in ion-irradiated stainless steel by nano-indentation technique

    Energy Technology Data Exchange (ETDEWEB)

    Oka, Hiroshi, E-mail: hiroshi_oka@eng.hokudai.ac.jp; Sato, Yutaka; Hashimoto, Naoyuki; Ohnuki, Somei

    2015-07-15

    Depth dependence of hardness in ion-irradiated 316 stainless steel was evaluated by the sectioning of damaged region and subsequent nano-indentation. The range of plastically deformed region by the nano-indentation was supplementarily investigated by transmission electron microscopy. When the indentation depth was the critical indentation depth, h{sub c}, which was derived from the Nix–Gao plot, the dislocation structure was observed from the specimen surface to right below the bottom of the ion-irradiated region. To verify the depth dependence of hardness, the “multi-layer model” was introduced in this study. The multi-layer model is based on the following assumptions; (1) the ion-irradiated region can be divided into sub-layers having their own local hardness, H{sub L}; (2) the hardness can be the product of f and H{sub L} in each sub-layer where f is the volume fraction of a deformation zone; and (3) the deformation zone can be a hemisphere. Eventually, through the sectioning and following nano-indentation, H{sub L} in each sub-layer was experimentally evaluated. Further the correlation between the displacement damage and the irradiation hardening ΔH in this study agreed with that of neutron irradiation experiments.

  13. Drug release from kollicoat SR 30D-coated nonpareil beads: Evaluation of coating level, plasticizer type, and curing condition

    OpenAIRE

    Shao, Zezhi J.; Morales, Luis; Diaz, Steven; Muhammad, Nouman A.

    2002-01-01

    A newly available polyvinylacetate aqueous dispersion, Kollicoat SR 30D, was evaluated with respect to its ability to modulate the in vitro release of a highly water-soluble model compound (diphenhydramine hydrochloride) from nonpareil-based systems. Kollicoat SR 30D premixed with a selected plasticizer (10% wt/wt propylene glycol, 2.5% triethyl citrate, or 2.5% dibutyl sebacute), talc, and red #30 lake dye was coated onto the drug beads in an Aeromatic Strea I fluid-bed drier with a Wurster ...

  14. Application of an electronic nose system for evaluation of unpleasant odor in coated tablets.

    Science.gov (United States)

    Ohmori, Shinji; Ohno, Yasuo; Makino, Tadashi; Kashihara, Toshio

    2005-02-01

    The purpose of this study was to apply an electronic nose system for evaluation of unpleasant odor in tablets containing L-cysteine, an unpleasant odor drug, and demonstrate the odor masking ability of thin-layer sugarless coated tablets, which we have newly developed, by both electronic nose system and sensory evaluations. We demonstrated the qualitative evaluation of the unpleasant odor using air as a reference indicator and the quantitative evaluation of the unpleasant odor using the distances between air and samples in the electronic nose system evaluation. The electronic nose system evaluation was positively and well-correlated with the sensory evaluation by volunteers. We suggest that the electronic nose system evaluation is appropriate as an alternative or a support method for sensory evaluation by volunteers. As the results of both electronic nose system and sensory evaluations, we demonstrated that the thin-layer sugarless coated tablets have excellent masking ability of the unpleasant odor, equivalent to that of sugar-coated tablets due to the dense coating layers.

  15. Preparation and performance evaluation of epoxy-based heat reflective coating for the pavement

    Science.gov (United States)

    Hu, B.; Liang, Y. H.; Guo, L. Y.; Jiang, T.

    2017-04-01

    According to the basic characteristics and composition of heat-reflective coating, combining with the functional requirements of road materials, the experiment selects the epoxy resin with good wear resistance and adhesive force as a film forming material, with TiO2, SiO2 and extinction powder as the main functional filler. The experiment gets a good formula with suitable viscosity, low glossiness and good cooling effect, optimizes by orthogonal experiment. The experiment evaluates the indoor and outdoor cooling effect of heat-reflective coating, and analyses the road performance of the coating. The results shows that the better heat-reflective coating formula included 12% of titanium dioxide, 4% of silica and 4% of extinction powder. When the dosage of coating is 0.8kg/m2, the indoor specimen of heat-reflective coating decrease the temperature of 12 ∼ 14°C, and the specimen under solar radiation can reduce the temperature of 7 ∼ 9°C. The pavement of heat-reflective coating has good wear resistance, but the road slip resistance partly declines. Therefore, it needs to add the anti-sliding particles to meet the safe driving requirements.

  16. Evaluation of methods to predict safe welding conditions and maximum HAZ hardness in steel welding

    Energy Technology Data Exchange (ETDEWEB)

    Tronskar, J.P. [Det Norske Veritas Industri Norge AS, Oslo (Norway)

    1993-12-31

    During the last ten years new structural steels of improved weldability have been introduced. In particular structural steels for the fabrication of offshore structures have been greatly improved in this respect throughout this period. These steels have lean chemical compositions which are generally outside the range for which the existing HAZ hardness criteria and the International Institute of Welding carbon equivalent (CEIIW) formula were originally developed. However, there are indications that the BS 5135:1984 method is not satisfactory for low carbon low CEIIW carbon equivalent steels. This paper presents the results from investigations of the weldability of three normalized (R{sub e min} 350 MPa) and three quenched and tempered (R{sub e min} 500 MPa) offshore structural steels. Weldability testing was conducted to study the relative performance of the different steels and to obtain a comparison between the capability of the different methods to predict safe welding conditions to avoid cold cracking in steel welding. Maximum HAZ hardness restrictions are often a point of contention between fabricators and their clients due to the difficulties often experienced in meeting these hardness requirements. Problems meeting maximum HAZ hardness requirements have been encountered for applications where NACE maximum hardness HRC 22 or Vickers HV10 260 have been imposed for materials exposed to sour service in oil and gas production, processing and transportation. Many attempts have been made to develop empirical formulae for the estimation of maximum HAZ hardnesses. This paper presents some of the more successful approaches proposed to date and compares their performance.

  17. Evaluation of edible polymer coatings enriched with green tea extract on quality of chicken nuggets.

    Science.gov (United States)

    Kristam, Prathyusha; Eswarapragada, Naga Mallika; Bandi, Eswara Rao; Tumati, Srinivas Rao

    2016-07-01

    The present study was conducted to evaluate the physico-chemical and microbiological characteristics of chicken nuggets coated with sodium alginate (SA) coatings at refrigerated (4±1°C) and frozen (-18±1°C) storage condition at regular periodic intervals. Chicken meat nuggets were separated into three groups: Uncoated control (C), coated with alginate coating (T1), and coated with alginate coating incorporated with 1% green tea extract (GTE) (T2). The nuggets were analyzed at regular intervals of 5days for refrigerated storage and 15 days for frozen storage period in terms of pH, 2-thiobarbituric acid value (TBA), peroxide value (PV), total plate count (TPC), water loss, and sensory characteristics. The results indicated that the nuggets coated with alginate-based coatings effectively reduced the spoilage as indicated by pH, TBA, and PVs. pH values of the formulations ranged from 6.15 to 6.34 at refrigerated storage temperature (4±1°C) and 6.49-6.71 at frozen storage temperature (-18±1°C). TBA value of the treatments ranged from 1.28 to 1.54 mg MDA/kg and 1.34 to 1.50 mg MDA/kg under refrigerated and frozen storage temperatures, respectively. Color, flavor, juiciness, tenderness, and overall acceptability of the nuggets differed significantly (pnuggets. The coated nuggets were well acceptable upto 15 days at refrigerated storage temperature (4±1°C) and upto 75 days at frozen storage temperature (-18±1°C). Nuggets coated with GTE incorporated coating solution had a lower TBA-reactive substances values, PVs, and TPCs when compared to the nuggets coated with SA and the control group. Study revealed that incorporation of edible coatings with antioxidants, namely, GTE at 1% level had a significant effect in reducing the fat oxidation. The samples recorded a shelf life of 15 days under refrigerated storage when compared to their controls with 10 days of storage period and 75 days under frozen storage against controls with 60 days. T1, T2, and T3 formulations

  18. Aespoe Hard Rock Laboratory. Evaluation of scaling records for TASA access tunnel

    Energy Technology Data Exchange (ETDEWEB)

    Ittner, Henrik (Chalmers Univ. of Technology, Goeteborg (Sweden))

    2009-07-01

    This report presents the result of a project accomplished during the summer 2009. It introduces a method to estimate the magnitude, mass distribution and cause of scaled blocks by tunnel mapping and evaluation of scaling data records. These issues are important for understanding the impact of the excavation method on the surrounding rock mass during excavation of the planned underground repository for spent nuclear fuel. The project includes mapping of the 3120 m drill and blast excavated part of the TASA access tunnel in the Aespoe Hard Rock Laboratory (HRL). In addition it includes development of a method for evaluation of the collected material together with scaling data records from the Site Characterization Database (SICADA). An interview has also been held with Erik Gabrielsson, who has been in charge of tunnel maintenance at Aespoe for many years. The mapping focused on to identify size and cause of areas with significant overbreaks in the tunnel roof. By distributing documented scaled volume in a tunnel section on several mapped overbreak areas in the same section it is possible to reconstruct the size of scaled blocks. The observed overbreak areas have been categorized in five different area types, depending on the cause of scaling: two geologically induced, one blast induced, one induced from a combination of geology and blasting and one unable to place in any category. For the calculated mass distribution the number of observations is declining with increasing block mass. 11% of the total blocks exceeding 400 Kg and 75% of the scaled blocks weights under 200 Kg. Most of the blocks are however lighter with 34% weighting 50 Kg or less. There is a relation between the mapped area type and the size distribution among the mapped overbreak areas. For example the areas caused by the end of blasting rounds are more frequently appearing then the other types but most of them are small in relation to the others The impression achieved from the tunnel mapping is

  19. Evaluation of Heat Checking and Washout of Heat Resistant Superalloys and Coatings for Die inserts

    Energy Technology Data Exchange (ETDEWEB)

    David Schwam; John F. Wallace; Yulong Zhu; Edward Courtright; Harold Adkins

    2005-01-30

    This project had two main objectives: (1) To design, fabricate and run a full size test for evaluating soldering and washout in die insert materials. This test utilizes the unique capabilities of the 350 Ton Squeeze Casting machine available in the Case Meal Casting Laboratory. Apply the test to evaluate resistance of die materials and coating, including heat resistant alloys to soldering and washout damage. (2) To evaluate materials and coatings, including heat resistant superalloys, for use as inserts in die casting of aluminum alloys.

  20. Characterization of Rockwell hardness indenter Tip using image processing and optical profiler and evaluation of measurement uncertainty

    Directory of Open Access Journals (Sweden)

    Moona G.

    2014-01-01

    Full Text Available Hardness is a measure of the resistance of a material to be penetrated and eroded by sharp projections of other materials such as diamond. The process of creating sharp projections on any test surface is known as indentation. Hardness measurement of any material is the result of a complex process of deformation during indentation. The indenter tip geometry, which includes radius of curvature at the tip and tip angle, affects the hardness measurement by influencing the nature of the penetration process on the test surface, because every indenter deforms the specimen surface with a different geometry. The controlled indenter geometry can improve the consistency of hardness measurement. In this paper we report the estimation of two important geometrical parameters, radius of curvature and tip angle of a Rockwell indenter by using a simple method of image processing and compare the results with those obtained with a traceable 3D optical profiler. Evaluation of uncertainty in measuremts is carried out as per ISO guidelines (ISO-GUM and a detailed uncertainty budget is presented. The tip angle estimted is 119.95 degree. The radius of curvature is estimted to be 199.96 ± 0.80μm by image analysis which agrees well with the value estimated by using optical profiler i.e. 199.12 μm.

  1. Evaluation of the linearity of soft- to hard-tissue movement after orthognathic surgery

    NARCIS (Netherlands)

    Chew, Ming Tak; Sandham, John; Wong, Hwee Bee

    2008-01-01

    Introduction: Our aim in this study was to investigate whether a linear relationship exists between soft- to hard-tissue changes for both maxillary and mandibular landmarks over a wide range of skeletal changes. Methods: The sample consisted of 30 Chinese patients with Class III malocclusion treated

  2. Is Chronic Dialysis the Right Hard Renal End Point To Evaluate Renoprotective Drug Effects?

    NARCIS (Netherlands)

    Weldegiorgis, Misghina; de Zeeuw, Dick; Dwyer, Jamie P.; Mol, Peter; Heerspink, Hiddo J. L.

    2017-01-01

    Background and objectives: RRT and doubling of serum creatinine are considered the objective hard end points in nephrology intervention trials. Because both are assumed to reflect changes in the filtration capacity of the kidney, drug effects, if present, are attributed to kidney protection.

  3. The evaluation of integrity and elasticity of thermally sprayed ceramic coatings by ultrasonics

    Energy Technology Data Exchange (ETDEWEB)

    Kauppinen, P. [VTT Manufacturing Technology, Espoo (Finland). Materials and Structural Integrity

    1997-12-31

    Thermally sprayed ceramic coatings are widely used in industrial applications where the coated component is subject to, e.g. high thermal loads or mechanical wear. The mechanical properties of the coating are finally created in the coating process and the chemical composition of the powder used as raw material can only give some hints about the properties of the final coating. Several non-destructive testing techniques are available for the detection of defects in ceramic materials or for the evaluation of density and density variations. In addition to this, ultrasonic techniques can be used for quantitative evaluation of elastic properties of materials. This evaluation is based on the measurement of sound velocities of different wave modes in the material and is normally applied only to relatively simple-shaped specimens having parallel surfaces. Acoustic microscopy operating at very high (> 100 MHz) frequencies has been used to measure the sound velocities in homogeneous and thin coatings. With this type of equipment, reliable and accurate results have been achieved in laboratory measurements. A lot of development work has been carried out world-wide to develop the measurement techniques and acoustic lenses (transducers) used in acoustic microscopy. However, less attention has been paid on the development of techniques for industrial applications on-site. The present work was focused on the development of measurement techniques for industrial applications. A new type of large-aperture low-frequency transducer was designed and constructed for the measurement of sound velocities in thermally sprayed ceramic coatings. The major difference to the lenses used in acoustic microscopy is that in the new transducer no separate lens is needed for focusing the sound beam. The piezoelectric element in the new transducer is a plastic (PVDF)-film that can be shaped to create the required focus. The practical measurement of the sound velocity is based on a modification of the V

  4. Evaluation of the efficiency of radioactive decontamination for alkyd and epoxy-urethane coating systems

    Science.gov (United States)

    Jevremović, Milutin; Milošević, Bratislav; Lazarević, Nataša

    2010-01-01

    This article presents experimental results obtained by the investigation of the efficiency of radioactive decontamination of a metal surface with alkyd and epoxy-urethane coating systems, which are used for the painting of military equipment. During the evaluation of the efficiency of decontamination, the impact of contaminants on the coating was not examined but the amount of contaminants residual after decontamination was, and was determined by activity measurements of the surface. The samples for testing were painted aluminum plates contaminated by liquid solutions of radioactive isotopes 60Co, 133Ba, 152Eu and 241Am (A=12297.91 Bq/ml). Decontamination of contaminated samples was performed with 0.5% detergent solution on the basis of synthetic surfactants. The activity measurements of samples were conducted using gamma spectroscopy system with a high-resolution high-purity germanium (HPGe) detector of relative efficiency of 50% at 60Co (1.33 MeV). The degree of removal of the radioactivity on the samples was observed as an indicator of the efficiency of decontamination. A comparison of the results is presented in relation to the retention time of the contamination on the surface coating, which is an important factor for the efficiency of decontamination. The samples with an alkyd coating system showed better efficiency of decontamination than the samples with the epoxy-urethane coating system, although the coatings based on epoxy and urethane resin were superior in relation to the alkyd in terms of protection, decorative characteristics and chemical resistance. The difference in the efficiency of decontamination for the examined coatings increases almost linearly in relation to the retention time of the contaminants in the coating.

  5. Microstructure and cytotoxicity evaluation of duplex-treated silver-containing antibacterial TiO₂ coatings.

    Science.gov (United States)

    Zhang, Xiangyu; Wu, Haibo; Geng, Zhenhua; Huang, Xiaobo; Hang, Ruiqiang; Ma, Yong; Yao, Xiaohong; Tang, Bin

    2014-12-01

    Implant-related infection is one of the most common and serious complications associated with biomedical implantation. To prevent bacterial adhesion, a series of porous TiO2 coatings with different concentrations of silver (designated as M0, M1, M2 and M3) were prepared on pure titanium substrates by a duplex-treatment technique combining magnetron sputtering with micro-arc oxidation. All coatings are porous with pore size less than 5 μm and the concentrations of silver in the M0, M1, M2 and M3 are 0, 0.95, 1.36 and 1.93 wt.%, respectively. Silver is found to be distributed throughout the thickness of the coatings by scanning electron microscopy. The release of silver from the TiO2 coatings was confirmed by an inductively-coupled plasma mass spectroscopy. The antibacterial effects of these coatings were tested against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli), and the cytotoxicity was evaluated using the mouse pre-osteoblast cells. The results indicate that the antibacterial activities of TiO2 coatings are greatly improved due to the incorporation of silver. No cytotoxic effect is found for the M1 surfaces from the observation of pre-osteoblast cell by MTT assay and fluorescence microscopy. Although the M2 and M3 coatings appeared to be toxic for pre-osteoblast cells after 1 day in culture, the cell viability on M2 and M3 surfaces was greatly raised after culturing for 2 days. Our results suggested that the TiO2 coatings incorporated with an optimum amount of silver can possess excellent antibacterial activities without cytotoxic effect, which has promising applications in biomedical devices. Copyright © 2014. Published by Elsevier B.V.

  6. Evaluation of biochemical urinary stone composition and its relationship to tap water hardness in Qom province, central Iran.

    Science.gov (United States)

    Moslemi, Mohammad Kazem; Saghafi, Hossein; Joorabchin, Seyed Mohammad Amin

    2011-01-01

    The aim of this study was to evaluate the biochemical stone composition in general population of Qom province, central Iran, and its relationship with high tap water hardness. In a prospective study, from March 2008 to July 2011, biochemical analysis of urinary stones in patients living in Qom province for at least 5 years was performed. Stones were retrieved by spontaneous passage, endoscopic or open surgery, and after extracorporeal shockwave lithotripsy. Demographic findings and the drinking water supply of patients were evaluated and compared with biochemical stone analysis. Stone analysis was performed in 255 patients. The most dominant composition of urinary stones was calcium oxalate (73%), followed by uric acid (24%), ammonium urate (2%), and cystine (1%). The peak incidence of urinary stone was in patients in their forties. Overall male to female ratio was 4.93:1. The dominant stone composition in inhabitants of central Iran, where tap water hardness is high, was calcium oxalate stones. On the basis of this study, biochemical urinary stone composition of Qom does not differ from other regions of Iran with lower water hardness.

  7. Microstructure Characterization and Hardness Evaluation of Alloy 52 Welded Stainless Steel 316 Subjected to Ultrasonic Nanocyrtal Surface Modification Technique

    Energy Technology Data Exchange (ETDEWEB)

    Kim, H. D.; Amanov, A.; Pyun, Y. S. [Sun Moon Univ., Asan (Korea, Republic of); Kim, Y. S.; Choi, Y. S. [Andong National Univ., Andong (Korea, Republic of)

    2015-10-15

    In this study, an ultrasonic nanocrystal surface modification (UNSM) technique was applied to dissimilar weld point between STS316L and Alloy 52. This UNSM technique is a patented technology, which can be described as a type of ultrasonic cold-forging technology. It has been demonstrated that the UNSM technique is a simple method to produce a nanocrystalline surface layer at the top surface of metallic materials. Microstructure and hardness of STS316L and Alloy 52 are investigated before and after UNSM treatment. It is expected according to the previous study that the UNSM technique is able to release the residual stress which delays PWSCC. In this study, microstructural characterization and hardness evaluation of STS316L and welded Alloy 52 subjected to UNSM technique were investigated.

  8. An Evaluation of Mechanical Properties with the Hardness of Building Steel Structural Members for Reuse by NDT

    Directory of Open Access Journals (Sweden)

    Masanori Fujita

    2016-10-01

    Full Text Available The reuse system proposed by the authors is one method to reduce the environmental burden in the structural field. As for reusable members, we take up building steel structures used for plants and warehouses. These buildings are assumed to be demolished within approximately 30 years or more for physical, architectural, economic, or social reasons in Japan. In this paper, the performance of steel structural members of a gable frame is evaluated with a non-destructive test for reuse. First, the flow to estimate mechanical properties of steel structural members such as tensile strength, yield strength, and elongation is shown via a non-destructive test. Next, tensile strength, yield strength, and elongation of steel structural members are estimated, with hardness measured with a portable ultrasonic hardness tester. Finally, the mechanical properties of steel structural members for reuse are estimated based on the proposed flow.

  9. Investigation of metallurgical coatings for automotive applications

    Science.gov (United States)

    Su, Jun Feng

    Metallurgical coatings have been widely used in the automotive industry from component machining, engine daily running to body decoration due to their high hardness, wear resistance, corrosion resistance and low friction coefficient. With high demands in energy saving, weight reduction and limiting environmental impact, the use of new materials such as light Aluminum/magnesium alloys with high strength-weight ratio for engine block and advanced high-strength steel (AHSS) with better performance in crash energy management for die stamping, are increasing. However, challenges are emerging when these new materials are applied such as the wear of the relative soft light alloys and machining tools for hard AHSS. The protective metallurgical coatings are the best option to profit from these new materials' advantages without altering largely in mass production equipments, machinery, tools and human labor. In this dissertation, a plasma electrolytic oxidation (PEO) coating processing on aluminum alloys was introduced in engine cylinder bores to resist wear and corrosion. The tribological behavior of the PEO coatings under boundary and starve lubrication conditions was studied experimentally and numerically for the first time. Experimental results of the PEO coating demonstrated prominent wear resistance and low friction, taking into account the extreme working conditions. The numerical elastohydrodynamic lubrication (EHL) and asperity contact based tribological study also showed a promising approach on designing low friction and high wear resistant PEO coatings. Other than the fabrication of the new coatings, a novel coating evaluation methodology, namely, inclined impact sliding tester was presented in the second part of this dissertation. This methodology has been developed and applied in testing and analyzing physical vapor deposition (PVD)/ chemical vapor deposition (CVD)/PEO coatings. Failure mechanisms of these common metallurgical hard coatings were systematically

  10. Evaluation of model parameters for simulating TiO(2) coated UV reactors.

    Science.gov (United States)

    Duran, J E; Taghipour, F; Mohseni, M

    2011-01-01

    A CFD-based model for simulating TiO(2) coated photocatalytic reactors used in drinking water treatment applications was preliminarily evaluated. The model includes aspects of hydrodynamics, mass transfer, UV-radiation field, and surface chemical reactions. Appropriate models for each of the associated physicochemical phenomena were experimentally or analytically examined. Once defined and evaluated, the individual models were integrated into a CFD-based model for simulating photocatalytic reactor performance, which was experimentally evaluated.

  11. EB/UV treatment of protective coatings for porous materials

    Energy Technology Data Exchange (ETDEWEB)

    Bemporad, E.; Carassiti, F.; Tata, A.; Gallinaro, G.; Paris, M

    2000-03-01

    A method for improving surface properties of porous inorganic materials is presented. The method is particularly tailored to cement-based materials in order to obtain properties suitable for mechanical applications such as dies manufacturing, where hardness, abrasion resistance and low friction are requested. The coating system is based upon using two coatings of different characteristics. The underlying base coating layer is infiltrated in air on three different formulations of hardened cement composite. Two different bi-component resins, one relatively soft and the other relatively hard, were tested as underlying surface coating. The outer surface coating, based upon a bi-component resin characterized by high hardness, is added after hardening and curing of the first layer. Both coatings were chemically hardened and then cured with EB. UV curing is also suitable for the outer surface coating. An experimental campaign was carried out in order to evaluate the influence of radiation processing as curing treatment with reference to particular investigated materials. Hardness and resistance to peeling of coating systems have been measured and are presented. (author)

  12. EB/UV treatment of protective coatings for porous materials

    Science.gov (United States)

    Bemporad, E.; Carassiti, F.; Tata, A.; Gallinaro, G.; Paris, M.

    2000-03-01

    A method for improving surface properties of porous inorganic materials is presented. The method is particularly tailored to cement-based materials in order to obtain properties suitable for mechanical applications such as dies manufacturing, where hardness, abrasion resistance and low friction are requested. The coating system is based upon using two coatings of different characteristics. The underlying base coating layer is infiltrated in air on three different formulations of hardened cement composite. Two different bi-component resins, one relatively soft and the other relatively hard, were tested as underlying surface coating. The outer surface coating, based upon a bi-component resin characterized by high hardness, is added after hardening and curing of the first layer. Both coatings were chemically hardened and then cured with EB. UV curing is also suitable for the outer surface coating. An experimental campaign was carried out in order to evaluate the influence of radiation processing as curing treatment with reference to particular investigated materials. Hardness and resistance to peeling of coating systems have been measured and are presented.

  13. Cutting applications of DLC, hard carbon and diamond films

    OpenAIRE

    Vandevelde, Thierry; VANDIERENDONCK, Kristine; VAN STAPPEN, M; Mong, W. D.; Perremans, P

    1999-01-01

    Due to their high hardness and low friction coefficient, diamond-like carbon (DLC), amorphous hard carbon (HC), and diamond coatings have great potential for dry cutting operations. The main differences between these coatings can be found in their hardness (respectively 2500, 5000-8000 and 10000 HV), morphology (DLC and HC: amorphous and diamond: crystalline) and their thermal stability (DLC, 250 degrees C, HC: 600 degrees C and diamond: 700 degrees C). DLC, HC and CVD diamond-coated hard ins...

  14. Evaluate the Effect of Commercially Available Denture Cleansers on Surface Hardness and Roughness of Denture Liners at Various Time Intervals

    Science.gov (United States)

    Mohammed, Hilal S.; Singh, Sumeet; Hari, Prasad A.; Amarnath, G. S.; Kundapur, Vinaya; Pasha, Naveed; Anand, M.

    2016-01-01

    Background and objective: Chemical cleansing by denture cleansers is first choice for denture plaque control. The most common problems while using denture cleansers are hardening, porosity, odor sorption, water sorption, solubility, and colour change, bacterial and fungal growth. Chemical cleansing procedures have been found to have an effect on the physical and mechanical properties of denture liners. Thus, this study was conducted to evaluate the effect of commercially available denture cleansers on surface hardness and roughness of acrylic and silicon based denture liners at various time interval. Method: Two autopolymerising denture liners Kooliner (acrylic) and GC reline soft (silicon) were tested with two commercially available denture cleansers, polident and efferdent plus. Total of 120 specimens were prepared and all the specimens were divided into six groups based on the relining materials and denture cleansers used. Surface hardness and surface roughness was tested using Shore A durometer and profilometer respectively at the end of day 1, day 7, day 30 and day 90. All the specimens were stored in artificial saliva throughout the study. Cleanser solution was prepared daily by adding Polident and Efferdent plus denture cleanser tablet into 250ml of enough very warm (not hot) water. Acrylic and silicon liner groups were cleansed in a solution of denture cleanser and water for 15 minutes daily, rinsed with water and stored in artificial saliva at room temperature. The data was analyzed with one way ANOVA and independent t-test. Result: The acrylic soft lining showed gradual hardening and increase in surface roughness after immersion in denture cleanser and also with time. Acrylic liner material showed maximum hardness and roughness with Polident followed by Efferdent plus and water (control group). Silicone lining material showed a slight difference in hardness and roughness between the test group and control group. There was a slight increase in hardness in

  15. EVALUATION OF BARRIERS TO THE USE OF RADIATION-CURED COATINGS IN SCREEN PRINTING

    Science.gov (United States)

    The report gives results of an evaluation of barriers to the use of radiation-cured coatings in screen printing. In support of the Source Reduction Review Project (SRRP), maximum achievable control technology (MACT) standards development, and the Pollution Prevention Act, EPA is ...

  16. Sputtered titanium oxynitride coatings for endosseous applications: Physical and chemical evaluation and first bioactivity assays

    Energy Technology Data Exchange (ETDEWEB)

    Banakh, Oksana, E-mail: oksana.banakh@he-arc.ch [Institute of Applied Microtechnologies, Haute Ecole Arc Ingénierie (HES-SO), Eplatures-Grise 17, CH-2300 La Chaux-de-Fonds (Switzerland); Moussa, Mira, E-mail: mira.moussa@unige.ch [Laboratory of Biomaterials, University of Geneva, 19, rue Barthelemy Menn, CH-1205 Geneva (Switzerland); Matthey, Joel, E-mail: joel.matthey@he-arc.ch [Institute of Applied Microtechnologies, Haute Ecole Arc Ingénierie (HES-SO), Eplatures-Grise 17, CH-2300 La Chaux-de-Fonds (Switzerland); Pontearso, Alessandro, E-mail: alessandro.pontearso@he-arc.ch [Institute of Applied Microtechnologies, Haute Ecole Arc Ingénierie (HES-SO), Eplatures-Grise 17, CH-2300 La Chaux-de-Fonds (Switzerland); Cattani-Lorente, Maria, E-mail: maria.cattani-lorente@unige.ch [Laboratory of Biomaterials, University of Geneva, 19, rue Barthelemy Menn, CH-1205 Geneva (Switzerland); Sanjines, Rosendo, E-mail: rosendo.sanjines@epfl.ch [Ecole Polytechnique Fédérale de Lausanne (EPFL), Institute of Condensed Matter Physics, Station 3, CH-1015 Lausanne (Switzerland); Fontana, Pierre, E-mail: Pierre.Fontana@hcuge.ch [Haemostasis laboratory, Geneva University Hospital, Rue Gabrielle-Perret-Gentil 4, CH-1205 Geneva (Switzerland); Wiskott, Anselm, E-mail: anselm.wiskott@unige.ch [Laboratory of Biomaterials, University of Geneva, 19, rue Barthelemy Menn, CH-1205 Geneva (Switzerland); Durual, Stephane, E-mail: stephane.durual@unige.ch [Laboratory of Biomaterials, University of Geneva, 19, rue Barthelemy Menn, CH-1205 Geneva (Switzerland)

    2014-10-30

    Highlights: • Titanium oxynitride coatings (TiN{sub x}O{sub y}) with chemical composition ranging from TiN to TiO{sub 2} were deposited by magnetron sputtering from a metallic Ti target using a mixture of O{sub 2} + N{sub 2}. • The coatings structure as well as physical, chemical and mechanical properties progressively changes as a function of oxygen content in the TiN{sub x}O{sub y.} • All TiN{sub x}O{sub y} coatings show a significantly higher level of bioactivity as compared to bare Ti substrates (1.2 to 1.4 fold increase in cell proliferation). Despite variations in surface chemistry, topography and surface tension observed on films as a function of chemical composition, no significant differences in the films’ biological activity were observed after 3 days of testing. - Abstract: Titanium oxynitride coatings (TiN{sub x}O{sub y}) are considered a promising material for applications in dental implantology due to their high corrosion resistance, their biocompatibility and their superior hardness. Using the sputtering technique, TiN{sub x}O{sub y} films with variable chemical compositions can be deposited. These films may then be set to a desired value by varying the process parameters, that is, the oxygen and nitrogen gas flows. To improve the control of the sputtering process with two reactive gases and to achieve a variable and controllable coating composition, the plasma characteristics were monitored in-situ by optical emission spectroscopy. TiN{sub x}O{sub y} films were deposited onto commercially pure (ASTM 67) microroughened titanium plates by reactive magnetron sputtering. The nitrogen gas flow was kept constant while the oxygen gas flow was adjusted for each deposition run to obtain films with different oxygen and nitrogen contents. The physical and chemical properties of the deposited films were analyzed as a function of oxygen content in the titanium oxynitride. The potential application of the coatings in dental implantology was assessed by

  17. Evaluation of self-healing ability of Ce–V conversion coating on AZ31 magnesium alloy

    Directory of Open Access Journals (Sweden)

    Xiao Jiang

    2016-09-01

    Full Text Available This study investigated the influence of cerium nitrate in vanadate solutions on the properties of Ce–V conversion coatings on AZ31 magnesium alloys, and evaluated the self-healing behavior of the Ce–V conversion coating for AZ31 magnesium alloy. The results showed that the additions of cerium nitrate prevented pentavalent vanadium from reducing to tetravalent vanadium in the coatings during conversion reaction process. Adding appropriate cerium nitrate to vanadate solution led to a thicker coating with a more compact CeVO4 layer. The corrosion behavior of the Ce–V conversion coating was investigated by the electrochemical tests and the scratch immersion test in 3.5 wt.% NaCl solution. The self-healing ability of the coating was confirmed from all tests. The surface analysis revealed that the self-healing effect of the Ce–V conversion coating was only provided by the release and migration of vanadium compounds.

  18. Evaluation of tack coating practices for asphalt overlays in Nebraska.

    Science.gov (United States)

    2017-04-03

    The strength of the bond between asphalt layers affects the lifespan of pavement structures. It is also a key factor in preventing major pavement distresses, such as slippage cracking and delamination. This research project evaluates and compares the...

  19. Corrosion and Nano-mechanical Behaviors of Magnetron Sputtered Al-Mo Gradient Coated Steel

    Science.gov (United States)

    Venugopal, A.; Srinath, J.; Ramesh Narayanan, P.; Sharma, S. C.; Venkitakrishnan, P. V.

    2017-01-01

    A gradient three-layer Al-Mo coating was deposited on steel using magnetron sputtering method. The corrosion and nano-mechanical properties of the coating were examined by electrochemical impedance spectroscopy and nano-indentation tests and compared with the conventional electroplated cadmium and IVD aluminum coatings. Electrochemical impedance spectroscopy was performed by immersing the coated specimens in 3.5% NaCl solution, and the impedance behavior was recorded as a function of immersion time. The mechanical properties (hardness and elastic modulus) were obtained from each indentation as a function of the penetration depth across the coating cross section. The adhesion resistance of the coatings was evaluated by scratch tests on the coated surface using nano-indentation method. The results show that the gradient Al-Mo coating exhibits better corrosion resistance than the other coatings in view of the better microstructure. The impedance results were modeled using appropriate electrical equivalent circuits for all the coated systems. The uniform, smooth and dense Al-Mo coating obtained by magnetron sputtering exhibits good adhesion with the steel substrate as per scratch test method. The poor corrosion resistance of the later coatings was shown to be due to the defects/cracks as well as the lesser adhesion of the coatings with steel. The hardness and elastic modulus of the Al-Mo coating are found to be high when compared to the other coatings.

  20. A microbiological evaluation of SiO2-coated textiles in hospital interiors

    DEFF Research Database (Denmark)

    Mogensen, Jeppe; Jørgensen, Poul-Erik; Thomsen, Trine Rolighed

    2016-01-01

    . From this perspective, the purpose of this paper is therefore to address focus on alternative passive coatings that without actively killing the bacteria provide a hydrophobic and easy-to-clean textile surface. The paper relates to an in-situ study evaluating the effect and cleaning potential of SiO2...... contact plates through a three-week period. By determining the level of contamination on these surfaces, the study illustrates that the SiO2-coated textile is possible to clean to an acceptable level below the critical limit value of 2,5 Colony Forming Units (CFU) per cm2. In comparison, the traditional...

  1. Chemical bonding in hard boron-nitride multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Jankowski, A.F.; Hayes, J.P.

    1997-06-01

    The oxides and nitrides of boron show great potential for use as hard, wear resistant materials. However, large intrinsic stresses and poor adhesion often accompany the hard coatings as found for the cubic boron-nitride phase. These effects may be moderated for use of a layered structure. Alternate stiff layers of boron and compliant layers of nitride are formed by modulating the sputter gas composition during deposition of boron target. The B/BN thin films are characterized with transmission electronic microscope to evaluate the microstructure, nanoindentation to measure hardness and ex-ray absorption spectroscopy to determine chemical bonding. The effects of layer pair spacing on chemical bonding and hardness are evaluated for the B/BN films.

  2. Evaluation of Metal Ion Concentration in Hard Tissues of Teeth in Residents of Central Poland

    Directory of Open Access Journals (Sweden)

    Piotr Wychowanski

    2017-01-01

    Full Text Available Objectives. The aim of the study was an assessment of the content of trace elements in enamel and dentin of teeth extracted in patients residing in urban and agricultural areas of Poland. Methods. The study included 30 generally healthy patients with retained third molars. 65 samples of enamel and dentin from individuals living in urban areas and 85 samples of enamel and dentin from individuals living in agricultural areas were prepared. The content of manganese, lead, cadmium, and chromium in the studied enamel and dentin samples from retained teeth was determined by Graphite Furnace Atomic Absorption Spectrometry. In the process of statistical hypothesis testing, the level of significance was assumed at α=0.05. Results. A comparative analysis of the data showed that enamel and dentin of inhabitants of industrialized areas contain significantly higher amounts of lead and cadmium than hard tissues of teeth in residents of agricultural areas and comparable amounts of manganese and chromium. Significance. It appears that hard tissues of retained teeth may constitute valuable material for assessment of long-term environmental exposure to metal ions. The study confirms that the risk of exposure to heavy metals depends on the place of residence and environmental pollution.

  3. Evaluation of methods to predict safe welding conditions and maximum HAZ hardness in steel welding

    Energy Technology Data Exchange (ETDEWEB)

    Tronskar, J.P. [Det Norske Veritas Industry, Oslo (Norway)

    1995-02-01

    During the last ten years new structural steels of improved weldability have been introduced. In particular, structural steels for the fabrication of offshore structures have been greatly improved in this respect throughout this period. These steels have lean chemical compositions which are generally outside the range for which the existing HAZ hardness criteria and the International Institute of Welding carbon equivalent (CEIIW) formula were originally developed. This paper presents the results from investigations of the weldability of three normalized (R{sub e} min 350 MPa) and three quenched and tempered (R{sub e} min 500 MPa) offshore structural steels. Weldability testing was conducted to study the relative performance of the different steels and to obtain a comparison between the capability of the different methods to predict safe welding conditions to avoid cold cracking in steel welding. It has become a widespread practice in welding high-strength steels to incorporate maximum HAZ hardness restrictions in fabrication specifications, particularly so in the offshore industry. This paper presents some of the more successful approaches proposed to date and compares their performance.

  4. Additive manufacturing of Ti-Si-N ceramic coatings on titanium

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yanning; Sahasrabudhe, Himanshu; Bandyopadhyay, Amit, E-mail: amitband@wsu.edu

    2015-08-15

    Highlights: • 3D Printing or additive manufacturing of hard Ti-Si-N based ceramics coating on Ti metal substrate. • Understanding of phase transformation as a function of compositional variation. • Evaluation of influence of processing parameters and composition on wear resistance. - Abstract: In this study, Laser Engineered Net Shaping (LENS{sup TM}) was employed towards Additive Manufacturing/3D Printing of Ti-Si-N coatings with three different Ti-Si ratios on commercially pure titanium (cp-Ti) substrate. Microstructural analysis, phase analysis using X-ray diffraction, wear resistance and hardness measurements were done on LENS™ processed 3D printed coatings. Coatings showed graded microstructures and in situ formed phases. Results showed that microstructural variations and phase changes influence coating's hardness and wear resistance directly. High hardness values were obtained from all samples’ top surface where the hardness of coatings can be ranked as 90% Ti-10% Si-N coating (2093.67 ± 144 HV{sub 0.2}) > 100% Ti-N coating (1846 ± 68.5 HV{sub 0.2}) > 75% Ti-25% Si-N coating (1375.3 ± 61.4 HV{sub 0.2}). However, wear resistance was more dependent on inherent Si content, and samples with higher Si content showed better wear resistance.

  5. Steam oxidation and the evaluation of coatings and material performance through collaborative research

    Energy Technology Data Exchange (ETDEWEB)

    Fry, A.T. [National Physical Lab., Teddington (United Kingdom); Aguero, A. [INTA, Madrid (Spain)

    2010-07-01

    Over the last five years through the COST 536 Programme researchers across Europe have been collaborating to better understand the phenomena of steam oxidation and to characterise coated and uncoated materials for use in power plants. During this period fundamental study of the oxidation mechanisms and changes in the oxidation kinetics caused by the presence of steam have been undertaken. Materials covering a range of high temperature plant applications have been studied, from low alloy martensitic alloys through to Ni-based superalloy materials, with investigations into the effect of increasing temperatures and pressures on the oxidation kinetics, oxide morphology and spallation characteristics. In addition conventional and novel coatings have been evaluated to assess their potential use in new USC plant. This paper will present an overview of these activities demonstrating the effect that steam has on the oxidation of alloys and coatings. (orig.)

  6. Invitro Evaluation of Fluoride Release from Hydroxyapatite Reinforced Glass Ionomer with or without Protective Coating.

    Science.gov (United States)

    Tiwari, Shilpi; Nandlal, Bhojraj

    2016-04-01

    Glass Ionomer Cement (GIC) is well known for its fluoride releasing property but has its own drawbacks of poor mechanical properties, sensitivity to initial desiccation and moisture contamination. To overcome these, search led to the reinforcement of hydroxyapatite and application of surface coating agent but their effect on fluoride release is still not clear. To evaluate and compare the release of fluoride from Hydroxyapatite Reinforced Glass Ionomer (HA-GIC) with and without protective coating. Specimens were prepared as follows- Eight percent by weight conventional glass ionomer was replaced by hydroxyapatite powder (HA) and an indigenous product was prepared (HA-GIC). This powder was mixed with liquid of conventional GIC and allowed to set, then G coat plus coating agent was applied in surface coated group and light cured. Fluoride release of the sample was measured every 24 hrs for seven days and weekly from 7(th) to 21(st) day using combination ion selective electrode. Mean values clearly reveal a significant decrease in the fluoride release from day 1 to day 21 for both the groups. Results of repeated measure ANOVA revealed statistically significant difference between two groups (p glass ionomer will allow for slow and steady release of fluoride for a long period of time into oral environment.

  7. Development and in vitro Evaluation of Enteric Coated Multiparticulate System for Resistant Tuberculosis.

    Science.gov (United States)

    Rahman, Md A; Ali, J

    2008-01-01

    The multiparticulate formulation of sodium para aminosalicylate for oral administration was developed by extrusion spheronization technique. Microcrystalline cellulose was used as filler in concentration of 14.4% w/w. Pellets were coated with Eudragit L 30 D-55 using fluidized bed processor. Different weight gains of acrylic polymer were applied onto the pellets and evaluated for in vitro dissolution behavior in 0.1 N HCl for two hours and then media was changed to phosphate buffer pH 6.8. A 60% w/w coating level of Eudragit L30 D 55 has produced the most acceptable results against the gastric attack. 3% Seal coat of HPMC E5 was also applied in order to protect the drug from migration into the Eudragit coat and film coat was applied in order to prevent aggregation of pellets in the dissolution media. Morphological characteristics of developed pellets were also investigated by scanning electron microscopy and found to be smooth and spherical. Developed system was found to be suitable for the delivery of Sod PAS in to intestinal region.

  8. Measurements of attenuation coefficient for evaluating the hardness of a cataract lens by a high-frequency ultrasonic needle transducer

    Science.gov (United States)

    Chen, Ruimin; Tsui, Po-Hsiang; Zhou, Qifa; Humayun, Mark S; Shung, K Kirk

    2010-01-01

    A cataract is a clouding of the lens in the eye that affects vision. Phacoemulsification is the mostly common surgical method for treating cataracts, and determining that the optimal phacoemulsification energy is dependent on measuring the hardness of the lens. This study explored the use of an ultrasound needle transducer for invasive measurements of ultrasound attenuation coefficient to evaluate the hardness of the cataract lens. A 47 MHz high-frequency needle transducer with a diameter of 0.9 mm was fabricated by a polarized PMN-33%PT single crystal in the present study. The attenuation coefficients at different stages of an artificial porcine cataract lens were measured using the spectral shift approach. The hardness of the cataract lens was also evaluated by mechanical measurement of its elastic properties. The results demonstrated that the ultrasonic attenuation coefficient was increased from 0.048 ± 0.02 to 0.520 ± 0.06 dB mm−1 MHz−1 corresponding to an increase in Young’s modulus from 6 ± 0.4 to 96 ± 6.2 kPa as the cataract further developed. In order to evaluate the feasibility of combining needle transducer and phacoemulsification probe for real-time measurement during cataract surgery, the needle transducer was mounted on the phacoemulsification probe for a vibration test. The results indicated that there was no apparent damage to the tip of the needle transducer and the pulse–echo test showed that a good performance in sensitivity was maintained after the vibration test. PMID:19759408

  9. Measurements of attenuation coefficient for evaluating the hardness of a cataract lens by a high-frequency ultrasonic needle transducer

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C.-C. [Department of Electronic Engineering, Fu Jen Catholic University, Taipei 24205, Taiwan (China); Chen Ruimin; Zhou Qifa; Shung, K Kirk [NIH Resource on Medical Ultrasonic Transducer Technology, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089 (United States); Tsui, P.-H. [Division of Mechanics, Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan (China); Humayun, Mark S [Doheny Retina Institute, Doheny Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033 (United States)], E-mail: j648816n@ms23.hinet.net

    2009-10-07

    A cataract is a clouding of the lens in the eye that affects vision. Phacoemulsification is the mostly common surgical method for treating cataracts, and determining that the optimal phacoemulsification energy is dependent on measuring the hardness of the lens. This study explored the use of an ultrasound needle transducer for invasive measurements of ultrasound attenuation coefficient to evaluate the hardness of the cataract lens. A 47 MHz high-frequency needle transducer with a diameter of 0.9 mm was fabricated by a polarized PMN-33%PT single crystal in the present study. The attenuation coefficients at different stages of an artificial porcine cataract lens were measured using the spectral shift approach. The hardness of the cataract lens was also evaluated by mechanical measurement of its elastic properties. The results demonstrated that the ultrasonic attenuation coefficient was increased from 0.048 {+-} 0.02 to 0.520 {+-} 0.06 dB mm{sup -1} MHz{sup -1} corresponding to an increase in Young's modulus from 6 {+-} 0.4 to 96 {+-} 6.2 kPa as the cataract further developed. In order to evaluate the feasibility of combining needle transducer and phacoemulsification probe for real-time measurement during cataract surgery, the needle transducer was mounted on the phacoemulsification probe for a vibration test. The results indicated that there was no apparent damage to the tip of the needle transducer and the pulse-echo test showed that a good performance in sensitivity was maintained after the vibration test.

  10. Evaluation of seed priming and coating on emergence, yield and ...

    African Journals Online (AJOL)

    Bread wheat production is constrained by climate change impacts and diseases in Amhara region. Pre-farming seed treatments are practiced worldwide to avert their effects on wheat. A field experiment was conducted at Adet and Finoteselam research stations in 2014 main cropping season to evaluate the effects of seed ...

  11. Clinical evaluation on the coaxial microincision cataract surgery in hard nuclear cataracts

    Directory of Open Access Journals (Sweden)

    Qing-Cheng Shi

    2013-05-01

    Full Text Available AIM: To assess and compare the results of 2.2mm microincision coaxial cataract surgery(MCCSphacoemulsification with the conventional 3.0mm MCCS in hard nuclear cataracts. METHODS: Totally 132 eyes with hard cataract(Ⅳ level and abovewere randomized to two groups: 2.2mm MCCS(group 1:60 eyesand 3.0mm MCCS(group 2:72 eyes. All patients underwent standard phacoemulsification and intraocular lens implantation surgery by one experienced surgeon. The average ultrasound power(AVEwas recorded during the operation. The incidences of capsule rupture and postoperative corneal edema were compared.Visual acuity, surgically induced astigmatism(SIAand the descent rate of endothelial cell density were compared at intervals of 1 day, 1 month and 3 months after surgery. Statistic analysis was taken by Student's t test and Chi square test. RESULTS: There was no significant difference on the incidences of capsule rupture, postoperative corneal edema and AVE(P> 0.05between the two groups(3.3%, 10.0%, 65.09±20.15and(4.2%, 11.1%, 69.13±15.44. One day after the surgery, the 2.2mm MCCS group showed better uncorrected visual acuity as compared to the 3.0mm MCCS group(P < 0.05. There were no significant differences on best-corrected visual acuity on 1 month and 3 months after the surgery. There was no significant difference on the descent rate of endothelial cell density(16.54%±10.20%, 17.69%±10.65%3 months after the surgery. One day, 1 month and 3 months after the surgery, SIA was 0.77±0.31,0.66±0.29, 0.52±0.25D in the 2.2mm MCCS group, and 1.41±0.73,0.98±0.61D,0.82±0.35D in the 3.0mm MCCS group, respectively. The differences were statistically significant. CONCLUSION: The operative safety of the 2.2mm MCCS group were the same as 3.0mm MCCS group with the hard nuclear cataracts. The 2.2mm MCCS phacoemulsification could significantly reduce SIA and get better earlier visual rehabilitation.

  12. General evaluation of hard dental tissue and risk factors of dental caries in young people

    Directory of Open Access Journals (Sweden)

    Антоніна Михайлівна Політун

    2016-04-01

    Full Text Available The prognostication of caries in youth is important for determination and prescription of individual prophylactic arrangements and its further influence on mineralization of the hard dental tissues.Aim of the work: the study of the prevalence and intensity of caries among the young people and determination of possible connection with the risk factor of caries development for further choice of the reasonable prophylactic arrangement.Materials and methods of research: epidemiological, clinical, statistic ones.Results of research: The article describes results of the comprehensive dental examination of 135 persons18-25 years old. There was determined the high prevalence of caries (96,3±0,74 % with considerable intensity (8,87±0,39. The main etiological factors among youth are: poor nutrition with prevalence of carbohydrate (74,81±0,56 %, lack of oral hygiene (59,27±0,73 %, quantitative and qualitative composition of oral fluid, presence of somatic diseases (40±0,30 %, bad habits (31,85±0,24 %, neglect of the sport (48,88±0,36 %, chronic emotional stress (38,51±0,29 %, due to the increased workload and related stress factors.Conclusions: the high prevalence (96,3±0,74 % and intensity of carious process (8,87±0,39 is caused by the unsatisfactory state of oral cavity, (1,91±0,06, under the influence of general factors (somatic diseases, stress, poor nutrition the reactivity of protective mechanisms is lowered and the risk of dental morbidity of youth increases. So, it proves the necessity of elaboration and introduction of the active arrangements of primary prophylaxis directed on the raise of caries resistance of the hard dental tissues in young people

  13. Evidence for a Cr metastable phase as a tracer in DLI-MOCVD chromium hard coatings usable in high temperature environment

    Science.gov (United States)

    Michau, Alexandre; Maury, Francis; Schuster, Frederic; Boichot, Raphael; Pons, Michel

    2017-11-01

    Cr deposits are widely used as protective coatings but multifunctional performances are required in harsh environments motivating research on new processes. MOCVD of Cr metal coatings was carried out by direct liquid injection (DLI) of a unique solution containing bis(ethylbenzene)chromium as metal source and thiophenol as inhibitor of carbide formation. A low amount (affected by the structural transformation because of the similarity of their crystallographic structures (both cubic), their density very close (a volume contraction of only 0.4% during the transformation) and its low content. This metastable phase is a signature of the DLI-MOCVD process and it can be used as a tracer for Cr coatings operating in high temperature environment without loss of the basic properties.

  14. Magnetic properties of α″-Fe16N2-like compound derived from Fe3O4 fine powder coated on hard magnetic BaFe12O19 particles

    Science.gov (United States)

    Tsugawa, Yuta; Matsumoto, Yoshiyuki; Masubuchi, Yuji; Uchikoshi, Tetsuo; Kikkawa, Shinichi

    2017-12-01

    An increase in magnetic coercivity is important for the α″-Fe16N2-like compound with an enhanced magnetization from α-Fe as a new hard magnetic material. In the present study, BaFe12O19 particles were coated with fine Fe3O4 powder produced by hydrolysis of Fe(acac)3 in benzyl alcohol. Smooth magnetization curves were obtained for the composite particles, suggesting they were magnetic hybrids with strong magnetic coupling between the Fe3O4 coating and the BaFe12O19 core particles. The Fe3O4 coating layer was then nitrided by ammonolysis at 150 °C to produce a dual-phase mixture of an α″-Fe16N2-like compound, which we refer to as ;α″-Fe16N2;, and residual α-Fe. Smooth magnetization hysteresis curves were obtained for (;α″-Fe16N2;)0.31(α-Fe)0.69/BaFe12O19 particles, and a magnetic coercivity of 199 mT, compared to the value of just 65 mT for (;α″-Fe16N2;)0.57(α-Fe)0.43 powder, indicating magnetic coupling between the core and shell structures. Thus, the hybrid particles exhibited both high magnetization and coercivity.

  15. Immobilisation of hydroxyapatite-collagen on polydopamine grafted stainless steel 316L: Coating adhesion and in vitro cells evaluation.

    Science.gov (United States)

    Tapsir, Zafirah; Jamaludin, Farah H; Pingguan-Murphy, Belinda; Saidin, Syafiqah

    2018-02-01

    The utilisation of hydroxyapatite and collagen as bioactive coating materials could enhance cells attachment, proliferation and osseointegration. However, most methods to form crystal hydroxyapatite coating do not allow the incorporation of polymer/organic compound due to production phase of high sintering temperature. In this study, a polydopamine film was used as an intermediate layer to immobilise hydroxyapatite-collagen without the introduction of high sintering temperature. The surface roughness, coating adhesion, bioactivity and osteoblast attachment on the hydroxyapatite-collagen coating were assessed as these properties remains unknown on the polydopamine grafted film. The coating was developed by grafting stainless steel 316L disks with a polydopamine film. Collagen type I fibres were then immobilised on the grafted film, followed by the biomineralisation of hydroxyapatite. The surface roughness and coating adhesion analyses were later performed by using AFM instrument. An Alamar Blue assay was used to determine the cytotoxicity of the coating, while an alkaline phosphatase activity test was conducted to evaluate the osteogenic differentiation of human fetal osteoblasts on the coating. Finally, the morphology of cells attachment on the coating was visualised under FESEM. The highest RMS roughness and coating adhesion were observed on the hydroxyapatite-collagen coating (hydroxyapatite-coll-dopa). The hydroxyapatite-coll-dopa coating was non-toxic to the osteoblast cells with greater cells proliferation, greater level of alkaline phosphate production and more cells attachment. These results indicate that the immobilisation of hydroxyapatite and collagen using an intermediate polydopamine is identical to enhance coating adhesion, osteoblast cells attachment, proliferation and differentiation, and thus could be implemented as a coating material on orthopaedic and dental implants.

  16. Effect of pulse current parameters on the mechanical and corrosion properties of anodized nanoporous aluminum coatings

    Energy Technology Data Exchange (ETDEWEB)

    Mohammadi, Iman, E-mail: imanmohammadi68@gmail.com; Ahmadi, Shahab; Afshar, Abdollah

    2016-11-01

    In this study, the effects of pulse current parameters on corrosion resistance and mechanical properties of anodized coatings were evaluated. Hardness measurements, polarization and electrochemical impedance spectroscopy tests were employed to investigate the mechanical properties and corrosion behavior of these coatings. Also, field emission scanning electron microscopy (FE-SEM) was used to analyze the surface morphology and microstructure of the coatings. It was found that the properties of anodized coatings were dependent on various parameters, among which, time, temperature and pulse current parameters (current density limit, frequency and duty cycle) were optimized. Analysis of Variance (ANOVA) was conducted in order to optimize the results of designed experiments for predicting the hardness of anodic Al{sub 2}O{sub 3} coatings. Experimental results showed that the temperature and the interaction of quadratic behavior of minimum current density with frequency and duty cycle were the most important factors influencing the hardness of these coatings. It was indicated that the highest hardness value of 642 HV was attained at the maximum and minimum current densities of 4.4, 1.27 A/dm{sup 2}, respectively, a frequency of 82 Hz, procedure time of 27.2 min, duty cycle of 80.2% and the bath temperature of 13.5 °C. In addition, the FE-SEM micrographs showed that the highest density is obtained through the mentioned optimum conditions. Moreover, the electrochemical tests revealed that the highest polarization resistance obtained at optimum conditions was more than 20 times greater than the other samples. - Highlights: • Electrolyte temperature undesirably influences the hardness of anodized coatings. • Maximum hardness of coatings was evaluated by optimization of effective parameters. • The diameter of alumina nanotube considerably affects hardness of anodized coating. • R{sub P} of the sample formed at optimum condition was at least 20 times more than others

  17. Evaluation of Caesalpinia bonduc seed coat extract for anti-inflammatory and analgesic activity

    Directory of Open Access Journals (Sweden)

    Dayanand M Kannur

    2012-01-01

    Full Text Available In the present work, Caesalpinia bonduc seed coat extract (CBSCE has been evaluated for anti-inflammatory and analgesic activity C. bonduc seeds have been attributed with anti-inflammatory and analgesic properties in the folklore medicine. Here in our study, we have tried to carry out the systematic evaluation of the seed coat extract of C. bonduc to substantiate these claims. C. bonduc seed coat was extracted with 95% ethanol and concentrated; further, the extract was screened for anti-inflammatory and analgesic activity. The studies were carried using Carrageenan-induced Paw Edema, Egg albumin-induced paw edema, Eddy′s Hot Plate Test, Tail Immersion Method so as to prove acclaimed properties. The data was analyzed statistically by Students′ ′t′ test. The results indicate that seed coat extract has the ability to decrease the induced inflammation at varied doses in Carrageenan model as well as in the Egg albumin model in rats. The antinociceptive results indicate that the extract has the ability to increase the pain threshold of the animals and reduce the pain factor, thereby inducing analgesia. Thus, it can be concluded that CBSCE posses analgesic and anti-inflammatory activity.

  18. Evaluation of Caesalpinia bonduc seed coat extract for anti-inflammatory and analgesic activity

    Science.gov (United States)

    Kannur, Dayanand M.; Paranjpe, Mukta P.; Sonavane, Lalit V.; Dongre, Prerana P.; Khandelwal, Kishanchand R.

    2012-01-01

    In the present work, Caesalpinia bonduc seed coat extract (CBSCE) has been evaluated for anti-inflammatory and analgesic activity C. bonduc seeds have been attributed with anti-inflammatory and analgesic properties in the folklore medicine. Here in our study, we have tried to carry out the systematic evaluation of the seed coat extract of C. bonduc to substantiate these claims. C. bonduc seed coat was extracted with 95% ethanol and concentrated; further, the extract was screened for anti-inflammatory and analgesic activity. The studies were carried using Carrageenan-induced Paw Edema, Egg albumin-induced paw edema, Eddy's Hot Plate Test, Tail Immersion Method so as to prove acclaimed properties. The data was analyzed statistically by Students’ ‘t’ test. The results indicate that seed coat extract has the ability to decrease the induced inflammation at varied doses in Carrageenan model as well as in the Egg albumin model in rats. The antinociceptive results indicate that the extract has the ability to increase the pain threshold of the animals and reduce the pain factor, thereby inducing analgesia. Thus, it can be concluded that CBSCE posses analgesic and anti-inflammatory activity. PMID:23057003

  19. Hardness Tester for Polyur

    Science.gov (United States)

    Hauser, D. L.; Buras, D. F.; Corbin, J. M.

    1987-01-01

    Rubber-hardness tester modified for use on rigid polyurethane foam. Provides objective basis for evaluation of improvements in foam manufacturing and inspection. Typical acceptance criterion requires minimum hardness reading of 80 on modified tester. With adequate correlation tests, modified tester used to measure indirectly tensile and compressive strengths of foam.

  20. Novel hydroxyapatite-forsterite-bioglass nanocomposite coatings with improved mechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Sebdani, M. Mazrooei, E-mail: m.mazrooei@ma.iut.ac.ir [Biomaterials Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Fathi, M.H. [Biomaterials Group, Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2011-02-03

    The purpose of this work was fabrication and evaluation of mechanical properties of hydroxyapatite-forsterite-bioactive glass nanocomposite coatings. The novel hydroxyapatite-forsterite-bioactive glass nanocomposite coating on 316L stainless steel (SS) was prepared via a sol-gel process. The X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and energy dispersive X-ray analysis (EDX) techniques were used to investigate the microstructure and morphology of the coatings. The local mechanical properties, e.g. nano-hardness, elastic modulus and fracture toughness of four type coatings with different amounts of forsterite, were determined by nano-indentation method using load and displacement data. The nano-indentation tester was equipped with Atomic Force Microscopy to image the indenter mark. The crack-free and homogeneous nanocomposite coatings with no observable defects were prepared. The coatings showed the hardness and elastic modulus values in the range of 2.4-3.4 (GPa) and 46-96 (GPa), respectively. The fracture toughness values of nanocomposite coatings also varied in the range of 0.56-0.972 (MPa m{sup 0.5}). The results showed that the elastic modulus, hardness and fracture toughness values of prepared composite coatings increased with increase in forsterite amounts. Results suggested that novel composite coatings might be potentially useful for biomedical applications especially as an implant coating for hard tissue treatment.

  1. Hard-yet-tough high-vanadium high-speed steel composite coating in-situ alloyed on ductile iron by atmospheric plasma arc

    NARCIS (Netherlands)

    Cao, Huatang; Dong, Xuanpu; Pei, Yutao T.

    2018-01-01

    A graded high-vanadium alloy composite coating was synthesized from premixed powders (V, Cr, Ti, Mo, Nb) on ductile iron (DI) substrate via atmospheric plasma arc surface alloying process. The resulted cross-section microstructure is divided into three distinct zones: upper alloyed zone (AZ) rich

  2. Abrasive Wear Resistance of the Iron- and WC-based Hardfaced Coatings Evaluated with Scratch Test Method

    Directory of Open Access Journals (Sweden)

    A. Vencl

    2013-06-01

    Full Text Available Abrasive wear is one of the most common types of wear, which makesabrasive wear resistance very important in many industries. Thehard facing is considered as useful and economical way to improve theperformance of components submitted to severe abrasive wear conditions, with wide range of applicable filler materials. The abrasive wear resistance of the three different hardfaced coatings (two iron‐based and one WC‐based, which were intended to be used for reparation of the impact plates of the ventilation mill, was investigated and compared. Abrasive wear tests were carried‐out by using the scratch tester under the dry conditions. Three normal loads of 10, 50 and 100 N and the constant sliding speed of 4 mm/s were used. Scratch test was chosen as a relatively easy and quick test method. Wear mechanism analysis showed significant influence of the hardfaced coatings structure, which, along with hardness, has determined coatings abrasive wear resistance.

  3. Wheat bread enrichment with hard-to-cook bean extruded flours: nutritional and acceptance evaluation.

    Science.gov (United States)

    Batista, Karla A; Prudêncio, Sandra H; Fernandes, Kátia F

    2011-01-01

    This study describes the enrichment of wheat bread with hard-to-cook black bean (BBEF) and cowpea (CEF) extruded flours. Breads containing 10% BBEF and 10% CEF presented increase of, respectively, 9% and 10% in protein content. In addition the fiber content was 2.6 higher in 10% BBEF bread and 2.2 higher in 10% CEF bread in comparison with standard bread. Despite protein and fiber increasing, the energetic value of substituted breads remained unchanged. An increase in the substitution to 15% resulted in decrease of specific volume and density of the breads. Results of sensory analysis to 10% BBEF bread presented overall appearance scores higher than standard bread and overall flavor acceptance very similar to standard. A total of 10% CEF bread presented similar appearance to those standard bread and 73% overall flavor acceptance. It is interesting to point out that distribution of 10% CEF bread overall flavor scores showed 3 distinct levels of consumer's sensibility. Practical Application: Breads enriched with extruded bean flours presented fiber and protein content improved and a very good consumer's acceptance. These results indicate that extruded bean flours constitute ingredients nutritionally and economically viable for technological application in breads elaboration, conferring improvement of nutritional characteristics without changing sensory attributes.

  4. Evaluating the Structure of Early English Literacy Skills in Deaf and Hard-of-Hearing Children.

    Science.gov (United States)

    Webb, Mi-Young; Lederberg, Amy R; Branum-Martin, Lee; McDonald Connor, Carol

    2015-10-01

    Better understanding the mechanisms underlying developing literacy has promoted the development of more effective reading interventions for typically developing children. Such knowledge may facilitate effective instruction of deaf and hard-of-hearing (DHH) children. Hence, the current study examined the multivariate associations among phonological awareness, alphabetic knowledge, word reading, and vocabulary skills in DHH children who have auditory access to speech. One hundred and sixty-seven DHH children (M age = 60.43 months) were assessed with a battery of early literacy measures. Forty-six percent used at least 1 cochlear implant; 54% were fitted with hearing aids. About a fourth of the sample was acquiring both spoken English and sign. Scores on standardized tests of phonological awareness and vocabulary averaged at least 1 standard deviation (SD) below the mean of the hearing norming sample. Confirmatory factor analyses showed that DHH children's early literacy skills were best characterized by a complex 3-factor model in which phonological awareness, alphabetic knowledge, and vocabulary formed 3 separate, but highly correlated constructs, with letter-sound knowledge and word reading skills relating to both phonological awareness and alphabetic knowledge. This supports the hypothesis that early reading of DHH children with functional hearing is qualitatively similar to that of hearing children. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Evaluating scintillator performance in time-resolved hard X-ray studies at synchrotron light sources

    Energy Technology Data Exchange (ETDEWEB)

    Rutherford, Michael E.; Chapman, David J.; White, Thomas G. [Imperial College London, London (United Kingdom); Drakopoulos, Michael [Diamond Light Source, I12 Joint Engineering, Environmental, Processing (JEEP) Beamline, Didcot, Oxfordshire (United Kingdom); Rack, Alexander [European Synchrotron Radiation Facility, Grenoble (France); Eakins, Daniel E., E-mail: d.eakins@imperial.ac.uk [Imperial College London, London (United Kingdom)

    2016-03-24

    Scintillator performance in time-resolved, hard, indirect detection X-ray studies on the sub-microsecond timescale at synchrotron light sources is reviewed, modelled and examined experimentally. LYSO:Ce is found to be the only commercially available crystal suitable for these experiments. The short pulse duration, small effective source size and high flux of synchrotron radiation is ideally suited for probing a wide range of transient deformation processes in materials under extreme conditions. In this paper, the challenges of high-resolution time-resolved indirect X-ray detection are reviewed in the context of dynamic synchrotron experiments. In particular, the discussion is targeted at two-dimensional integrating detector methods, such as those focused on dynamic radiography and diffraction experiments. The response of a scintillator to periodic synchrotron X-ray excitation is modelled and validated against experimental data collected at the Diamond Light Source (DLS) and European Synchrotron Radiation Facility (ESRF). An upper bound on the dynamic range accessible in a time-resolved experiment for a given bunch separation is calculated for a range of scintillators. New bunch structures are suggested for DLS and ESRF using the highest-performing commercially available crystal LYSO:Ce, allowing time-resolved experiments with an interframe time of 189 ns and a maximum dynamic range of 98 (6.6 bits)

  6. Evaluation of DNA typing as a positive identification method for soft and hard tissues immersed in strong acids.

    Science.gov (United States)

    Robino, C; Pazzi, M; Di Vella, G; Martinelli, D; Mazzola, L; Ricci, U; Testi, R; Vincenti, M

    2015-11-01

    Identification of human remains can be hindered by several factors (e.g., traumatic mutilation, carbonization or decomposition). Moreover, in some criminal cases, offenders may purposely adopt various expedients to thwart the victim's identification, including the dissolution of body tissues by the use of corrosive reagents, as repeatedly reported in the past for Mafia-related murders. By means of an animal model, namely porcine samples, we evaluated standard DNA typing as a method for identifying soft (muscle) and hard (bone and teeth) tissues immersed in strong acids (hydrochloric, nitric and sulfuric acid) or in mixtures of acids (aqua regia). Samples were tested at different time intervals, ranging between 2 and 6h (soft tissues) and 2-28 days (hard tissues). It was shown that, in every type of acid, complete degradation of the DNA extracted from soft tissues preceded tissue dissolution and could be observed within 4h of immersion. Conversely, high molecular weight DNA amenable to STR analysis could be isolated from hard tissues as long as cortical bone fragments were still present (28 days for sulfuric acid, 7 days for nitric acid, 2 days for hydrochloric acid and aqua regia), or the integrity of the dental pulp chamber was preserved (7 days, in sulfuric acid only). The results indicate that DNA profiling of acid-treated body parts (in particular, cortical bone) is still feasible at advanced stages of corrosion, even when the morphological methods used in forensic anthropology and odontology can no longer be applied for identification purposes. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  7. Development and Evaluation of a Water-Based Flame Retardant Spray Coating for Cotton Fabrics.

    Science.gov (United States)

    Zope, Indraneel S; Foo, Shini; Seah, Dean G J; Akunuri, Aswini Tara; Dasari, Aravind

    2017-11-22

    In this Research Article, we report on the development of water-based flame retardant coating based on phospho-nitrogen combination for cotton fabrics. A one-step spray-on process was employed to coat the fabrics by taking advantage of the spontaneous reaction between para-phenylenediamine (PDA) and tetrakis(hydroxymethyl)phosphonium chloride (THPC) resulting in an instantaneous precipitation of poly[1,4-diaminophenylene-tris(dimethyl hydroxymethyl)phosphine] (PApP) on the fabric surface. The effectiveness of PApP in improving the flame retardant properties like ignition resistance and lateral flame spread were evaluated in accordance with ASTM D6413 and BS EN ISO 15025 flammability tests. Despite the early (thermal) decomposition onset for coated fabrics under both oxidative and pyrolytic conditions, remarkably, self-extinguishing behavior (<3 s) without any lateral flame spread was observed. Possible reaction scheme was also proposed to correlate flame retardant mechanism of the coated fabrics with the observations. Additional analysis via pyrolysis combustion flow calorimetry and vertical flame testing before and after washing showed that flame retardant efficiency did decrease with washing, but the overall performance was still promising.

  8. Antibacterial coating on polymer for space application

    Energy Technology Data Exchange (ETDEWEB)

    Balagna, Cristina, E-mail: cristina.balagna@polito.it [Institute of Materials Physics and Engineering, Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Perero, Sergio; Ferraris, Sara; Miola, Marta [Institute of Materials Physics and Engineering, Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Fucale, Giacomo [Chemical, Clinical and Microbiological Analyses Department C.T.O., Via G. Zuretti 29, 10126 Torino (Italy); Manfredotti, Chiara; Battiato, Alfio [Physics Department, Centre of Excellence ' Nanostructured Interfaces and Surfaces' and CNISM, University of Torino, Via P. Giuria 1, 10125 Torino (Italy); Santella, Daniela [Thales Alenia Space - Italia, Space Infrastructures and Transportation, Engineering - Advanced Projects Unit, Strada Antica di Collegno 253, 10146 Torino (Italy); Verne, Enrica [Institute of Materials Physics and Engineering, Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Vittone, Ettore [Physics Department, Centre of Excellence ' Nanostructured Interfaces and Surfaces' and CNISM, University of Torino, Via P. Giuria 1, 10125 Torino (Italy); Ferraris, Monica [Institute of Materials Physics and Engineering, Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2012-08-15

    The microbiological contamination on board of spacecraft and orbital stations is a relevant problem in prolonged space exploration. For this purpose, an antibacterial silver nanocluster silica composite coating was deposited on a commercial polymer Combitherm{sup Registered-Sign }, suitable for aerospace application, using the radio frequency (RF) co-sputtering technique. The presence of metallic silver nanoclusters and silica was confirmed by energy dispersion spectrometry (EDS), x-ray photoelectron spectroscopy (XPS) and localized surface plasmon resonance (LSPR) detected through UV-visible absorption spectrophotometry (UV-Vis). The atomic force microscope (AFM) evidenced the coating morphology. The slight hydrophobicity of both coated and uncoated samples was revealed through the contact angle measurement. The antimicrobial behavior was verified through evaluation of the inhibition halo against several bacterial and fungal species. The coating enhanced the Combitherm{sup Registered-Sign} nano-hardness and its resistance to tensile and perforation tests; the coating wear resistance was measured by abrasion test against Kevlar. A folding procedure on the coated Combitherm{sup Registered-Sign} and storage in air for three months was also carried out without deterioration of the measured properties. The coating deposition did not influence the air permeability of Combitherm{sup Registered-Sign }. -- Highlights: Black-Right-Pointing-Pointer A silver nanocluster silica composite coating was deposited on a polymeric film. Black-Right-Pointing-Pointer A co-sputtering technique was used for the coating deposition. Black-Right-Pointing-Pointer The coating induced an antibacterial effect on the polymer film. Black-Right-Pointing-Pointer The coating improved the nano-hardness and the resistance to tensile and perforation.

  9. Coatings and Corrosion Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — Purpose: The mission of the Coatings and Corrosion Laboratory is to develop and analyze the effectiveness of innovative coatings test procedures while evaluating the...

  10. Formulation and evaluation of sustained release enteric-coated pellets of budesonide for intestinal delivery.

    Science.gov (United States)

    Raval, Mihir K; Ramani, Riddhi V; Sheth, Navin R

    2013-10-01

    The aim of present work was to develop intestinal-targeted pellets of Budesonide, a potent glucocorticoid, used for the treatment of ulcerative colitis and Crohn's disease by extrusion and spheronization method. Current available oral formulations of Budesonide have low efficacy because of the premature drug release in the upper part of the gastrointestinal tract. In this study, a pH-controlled intestinal-targeted pellet of budesonide was established using 3(2) full factorial design by giving an enteric coating with Eudragit S100. Budesonide-sustained release pellets were prepared by extruder and spheronization technique using a combination of water-soluble and permeable polymers by applying 3(2) full factorial design. The pellets were coated by spray coating technique using Eudragit S100 as an enteric polymer. The pellets were characterized for its flowability, sphericity, friability, and in vitro drug release. Release behaviour was studied in different pH media. The release profile was studied for the mechanism of drug release. The optimized formulation showed negligible drug release in the stomach followed by release for 12 h in the intestinal pH. Differential scanning calorimetry and Fourier Transform Infrared Spectroscopy studies indicated no interaction between drug and polymer. Scanning Electron Microscopy image of coated pellets suggested a uniform and smooth coat over the surface of pellets. Accelerated stability studies showed a stable nature of drug in the formulation. All evaluation parameter showed that pellets were good in spherocity and flowability. Sustained release pellets of Budesonide could be prepared by extrusion and spheronization which released the drug in intestinal pH for an intestine to treat inflammatory bowel disease. A ratio of polymer combination could be decided using a full factorial design.

  11. Drug coated microneedles for minimally-invasive treatment of oral carcinomas: development and in vitro evaluation.

    Science.gov (United States)

    Ma, Yunzhe; Boese, Seth E; Luo, Zhen; Nitin, Nitin; Gill, Harvinder S

    2015-04-01

    Treatment of recurring oral cancers is challenging as common surgical approaches are not feasible for these patients. In addition, these patients do not respond well to systemic chemotherapy. Localized intratumoral injection of anti-cancer drugs is considered to be an attractive alternative treatment approach for these patients. However, conventional hypodermic injections result in poor distribution of the drug in the tumor and leakage of the drug from the injection site to systemic circulation, in addition to causing pain to the patient. The objective of this study was to develop coated microneedles as a novel device for direct and minimally invasive intratumoral delivery of anti-cancer drugs. Poly(lactic-co-glycolic) acid (PLGA) nanoparticles encapsulating doxorubicin (DOX) were prepared and coated on inplane (1D) microneedles. Microscopic evaluation of 3D tissue phantoms and porcine cadaver buccal tissues that were treated with 1D microneedle arrays coated with DOX-PLGA nanoparticles demonstrated that DOX could diffuse both laterally and vertically in to the tissues and produced cellular cytotoxicity. Out of plane (2D) microneedle arrays measuring 1 cm x 1 cm with 57 microneedles coated with free DOX could produce uniform distribution of DOX in a porcine cadaver buccal tissue up to a depth greater than 3 mm. Hypodermic injection of different volumes in to a porcine buccal tissue confirmed significant leakage of the injected volume (about 25% of the injected 80 μl). In summary, this study demonstrates that drug coated microneedles is an attractive microscale device that can uniformly and effectively deliver drugs to localized oral cancers. This microscale device has potential to impact the treatment of oral cancer patients.

  12. Evaluation of experimental coating to improve the zirconia-veneering ceramic bond strength.

    Science.gov (United States)

    Matani, Jay D; Kheur, Mohit; Jambhekar, Shantanu Subhashchandra; Bhargava, Parag; Londhe, Aditya

    2014-12-01

    To evaluate the shear bond strength (SBS) between zirconia and veneering ceramic following different surface treatments of zirconia. The efficacy of an experimental zirconia coating to improve the bond strength was also evaluated. Zirconia strips were fabricated and were divided into four groups as per their surface treatment: polished (control), airborne-particle abrasion, laser irradiation, and application of the experimental coating. The surface roughness and the residual monoclinic content were evaluated before and after the respective surface treatments. A scanning electron microscope (SEM) analysis of the experimental surfaces was performed. All specimens were subjected to shear force in a universal testing machine. The SBS values were analyzed with one-way ANOVA followed by Bonferroni post hoc for groupwise comparisons. The fractured specimens were examined to observe the failure mode. The SBS (29.17 MPa) and roughness values (0.80) of the experimental coating group were the highest among the groups. The residual monoclinic content was minimal (0.32) when compared to the remaining test groups. SEM analysis revealed a homogenous surface well adhered to an undamaged zirconia base. The other test groups showed destruction of the zirconia surface. The analysis of failure following bond strength testing showed entirely cohesive failures in the veneering ceramic in all study groups. The experimental zirconia surface coating is a simple technique to increase the microroughness of the zirconia surface, and thereby improve the SBS to the veneering ceramic. It results in the least monoclinic content and produces no structural damage to the zirconia substructure. © 2014 by the American College of Prosthodontists.

  13. In Vitro and In Vivo Evaluation of Tetracycline Loaded Chitosan-Gelatin Nanosphere Coatings for Titanium Surface Functionalization.

    Science.gov (United States)

    Ma, Kena; Cai, Xinjie; Zhou, Yi; Wang, Yining; Jiang, Tao

    2017-02-01

    Owing to the biocompatibility of titanium surface, titanium implants are suitable substrates for microbial colonization and biofilm formation, which is still a serious clinical threat. Current research trends have been focused on the development of antibacterial coatings on titanium substrate or adhesion resistant surface. In our previous study, tetracycline (Tc) loaded chitosan-gelatin (CSG) nanosphere coatings are successfully fabricated on titanium substrates via electrophoretic deposition. These coatings show nanosphere structure, and excellent antibacterial property in vitro. However, further in vitro and in vivo evaluation of the coatings is required for the future application. Therefore, in the present study, the authors investigate the coatings' mechanical, swelling and degradation property, in vitro cellular response to preosteoblast cells, and the antibacterial property in rabbits. Results show that Tc incorporation can improve the tensile bond strength of the coating, decrease the swelling ratio, and accelerate the degradation of the coating. Although high Tc concentration group exhibits cytotoxicity to MC3T3-E1 cells, its in vivo antibacterial property is preferred, and shows better outcome than the prophylactic administration of Tc. Tc loaded CSG nanosphere coatings are suitable antibacterial coatings for titanium surface functionalization. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Fabrication and evaluation of a pulse laser-induced Ca-P coating on a Ti alloy for bioapplication

    Energy Technology Data Exchange (ETDEWEB)

    Paital, Sameer R; Dahotre, Narendra B [Department of Materials Science and Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Balani, Kantesh; Agarwal, Arvind, E-mail: ndahotre@utk.ed [Department of Mechanical and Materials Engineering, Florida International University, EAS 3400, Miami, FL 33174 (United States)

    2009-02-15

    In the present paper, we demonstrate the feasibility of depositing a tailored calcium phosphate (Ca-P) coating on a Ti-6Al-4V substrate by using a pulsed Nd:YAG laser system. Different textures were obtained by varying the laser spot overlap with change in laser traverse speed. Surface roughness measurements using laser confocal microscopy indicated a decrease in roughness with increasing laser scan speed. X-ray diffraction studies revealed the formation of alpha-TCP, TiO{sub 2}, Ti and Al as the major phases. An instrumented nanoindenation technique used to study the mechanical properties of the coatings, revealed a very high hardness and Young's modulus of the coating surface as compared to the substrate. This further proved the retainment of the ceramic phase on the surface. Wear studies in a simulated biofluid (SBF) environment demonstrated an increased wear resistance of the coated samples as compared to the bare Ti-6Al-4V. Formation of an apatite-like layer after immersion in SBF for different time periods further demonstrated the bioactivity of the coated samples.

  15. Microstructural and mechanical evaluation of laser-assisted cold sprayed bio-ceramic coatings: potential use for biomedical applications

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2014-02-01

    Full Text Available Journal of Thermal Spray Technology Microstructural and Mechanical Evaluation of Laser-Assisted Cold Sprayed Bio- ceramic Coatings: Potential Use for Biomedical Applications  Monnamme Tlotleng  Esther Akinlabi  Mukul Shukla  Sisa Pityana...

  16. In vitro evaluation of novel polymer-coated magnetic nanoparticles for controlled drug delivery.

    Science.gov (United States)

    Rahimi, Maham; Wadajkar, Aniket; Subramanian, Khaushik; Yousef, Monet; Cui, Weina; Hsieh, Jer-Tsong; Nguyen, Kytai Truong

    2010-10-01

    Previously uncharacterized poly(N-isopropylacrylamide-acrylamide-allylamine)-coated magnetic nanoparticles (MNPs) were synthesized using silane-coated MNPs as a template for radical polymerization of N-isopropylacrylamide, acrylamide, and allylamine. Properties of these nanoparticles such as size, biocompatibility, drug loading efficiency, and drug release kinetics were evaluated in vitro for targeted and controlled drug delivery. Spherical core-shell nanoparticles with a diameter of 100 nm showed significantly lower systemic toxicity than did bare MNPs, as well as doxorubicin encapsulation efficiency of 72%, and significantly higher doxorubicin release at 41°C compared with 37°C, demonstrating their temperature sensitivity. Released drugs were also active in destroying prostate cancer cells (JHU31). Furthermore, the nanoparticle uptake by JHU31 cells was dependent on dose and incubation time, reaching saturation at 500 μg/mL and 4 hours, respectively. In addition, magnetic resonance imaging capabilities of the particles were observed using agarose platforms containing cells incubated with nanoparticles. Future work includes investigation of targeting capability and effectiveness of these nanoparticles in vivo using animal models. In this paper, previously uncharacterized magnetic nanoparticles were synthesized using silane-coated MNPs as a template for radical polymerization of N-isopropylacrylamide, acrylamide, and allylamine. Various properties of these nanoparticles were evaluated in vitro for targeted drug delivery. Copyright © 2010 Elsevier Inc. All rights reserved.

  17. Evaluation of a dehumidifier with adsorbent coated heat exchangers for tropical climate operations

    KAUST Repository

    Oh, Seung Jin

    2017-03-10

    This paper presents the evaluation of a solid desiccant dehumidifier equipped with adsorbent powder coated heat exchangers (PCHX). The main component of the solid desiccant dehumidifier includes two heat exchangers that are coated with silica gel RD type powders in order to increase water adsorption uptake by improving its heat and mass transfer. A series of experiment are conducted to evaluate two key performance indices, namely, moisture removal capacity (MRC) and thermal coefficient performance (COPth), under various hot and humid air conditions. Conventional granular adsorbent packed heat exchangers (GPHX) are employed to benchmark the performance of the adsorbent coated heat exchanger (PCHX). Results reveal that the PCHX exhibits higher uptake performance due to better heat and mass transfer. It is found that the moisture removal capacity increases from 7.4 g/kg to 11.0 g/kg with air flow rates of 35 kg/h, resulting in the extended contact time of the water vapor. Experiments also demonstrate that the moisture removal capacity is highly affected by inlet air humidity ratio. In addition, marked improvement in COPth can be achieved by a lowered hot water regeneration temperature.

  18. Coating process and early stage adhesion evaluation of poly(2-hydroxy-ethyl-methacrylate) hydrogel coating of 316L steel surface for stent applications.

    Science.gov (United States)

    Indolfi, Laura; Causa, Filippo; Netti, Paolo Antonio

    2009-07-01

    In this study, a spray-coating method has been set up with the aim to control the coating of poly(2-hydroxy-ethyl-methacrylate) (pHEMA), an hydrophilic polymeric hydrogel, onto the complex surface of a 316L steel stent for percutaneous coronary intervention (PCI). By varying process parameters, tuneable thicknesses, from 5 to 20 microm, have been obtained with uniform and homogeneous surface without crack or bridges. Surface characteristics of pHEMA coating onto metal surface have been investigated through FTIR-ATR, contact angle measurement, SEM, EDS and AFM. Moreover, results from Single-Lap-Joint and Pull-Off adhesion tests as well as calorimetric analysis of glass transition temperature suggested that pHEMA deposition is firmly adhered on metallic surface. The pHEMA coating evaluation of roughness, wettability together with its morphological and chemical stability after three cycles of expansion-crimping along with preliminary results after 6 months demonstrates the suitability of the coating for surgical implantation of stent.

  19. Electrochemical Evaluation of a Recycled Copolymer Coating for Cultural Heritage Conservation Purposes

    Directory of Open Access Journals (Sweden)

    Marco Hernández-Escampa

    2013-01-01

    Full Text Available Acrylonitrile-butadiene-styrene (ABS is a well-known discard product from the industry. This copolymer can be dissolved in organic solvents, and thin films can be created by immersion. Two requirements for coatings used for cultural heritage conservation purposes are transparency and reversibility, both fulfilled by ABS films. The aim of this work was to characterize the copolymer and to evaluate the electrochemical properties of ABS coatings applied to copper. Such performance was compared to that of a commercial varnish commonly used in conservation. The results indicate high protection values of the ABS film, generating a potential application for this waste material. The electrochemical techniques included electrochemical noise, impedance spectroscopy, and potentiodynamic polarization.

  20. Evaluation of elastic modulus and hardness of crop stalks cell walls by nano-indentation

    Science.gov (United States)

    Yan Wu; Siqun Wang; Dingguo Zhou; Cheng Xing; Yang Zhang; Zhiyong Cai

    2010-01-01

    Agricultural biomaterials such as crop stalks are natural sources of cellulosic fiber and have great potential as reinforced materials in bio-composites. In order to evaluate their potential as materials for reinforcement, the nano-mechanical properties of crop-stalk cell walls, i.e. those of cotton (Gossypium herbaceu) stalk, soybean (Glycine max) stalk, cassava (...

  1. Axisymmetric fretting analysis in coated cylinder

    Indian Academy of Sciences (India)

    erties by coating the surface. There is rather scanty literature available on fretting analysis of coated components. Presence of such coatings has a large influence on the near surface state of stress. The effect of coatings on the severity of fretting is the focus of this paper. Results obtained for both hard and soft coatings are ...

  2. Preparation and evaluation of graphene-coated solid-phase microextraction fiber

    Energy Technology Data Exchange (ETDEWEB)

    Chen Jinmei; Zou Jing; Zeng Jingbin; Song Xinhong; Ji Jiaojiao; Wang Yiru [Department of Chemistry and the Key Laboratory of Analytical Sciences of the Ministry of Education, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); Ha, Jaeho [Food Analysis Center, Korea Food Research Institute, San 46-1, Baekhyun, Bundang, Seongnam, Gyonggi Province 463-746 (Korea, Republic of); Chen Xi, E-mail: xichen@xmu.edu.cn [Department of Chemistry and the Key Laboratory of Analytical Sciences of the Ministry of Education, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005 (China); State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen 361005 (China)

    2010-09-23

    In this paper, a novel graphene (G) based solid-phase microextraction (SPME) fiber was firstly prepared by immobilizing the synthesized G on stainless steel wire as coating. The new fiber possessed a homogeneous, porous and wrinkled surface and showed excellent thermal (over 330 {sup o}C), chemical and mechanical stability, and long lifespan (over 250 extractions). The SPME performance of the G-coated fiber was evaluated in detail through extraction of six pyrethroid pesticides. Although the thickness of G-coated fiber was only 6-8 {mu}m, its extraction efficiencies were higher than those of two commercial fibers (PDMS, 100 {mu}m; PDMS/DVB, 65 {mu}m). This high extraction efficiency may be mainly attributed to huge delocalized {pi}-electron system of G, which shows strong {pi}-stacking interaction with pyrethroid pesticide. The G-coated fiber was applied in the gas chromatographic determination of six pyrethroids, and their limits of detection were found to be ranged from 3.69 to 69.4 ng L{sup -1}. The reproducibility for each single fiber was evaluated and the relative standard deviations (RSDs) were calculated to be in the range from 1.9% to 6.5%. The repeatability of fiber-to-fiber and batch-to-batch was 4.3-9.2% and 4.1-9.9%. The method developed was successfully applied to three pond water samples, and the recoveries were 83-110% at a spiking of 1 {mu}g L{sup -1}.

  3. TECHNICAL EVALUATION OF THE SAFE TRANSPORTATION OF WASTE CONTAINERS COATED WITH POLYUREA

    Energy Technology Data Exchange (ETDEWEB)

    VAIL, T.S.

    2007-03-30

    This technical report is to evaluate and establish that the transportation of waste containers (e.g. drums, wooden boxes, fiberglass-reinforced plywood (FRP) or metal boxes, tanks, casks, or other containers) that have an external application of polyurea coating between facilities on the Hanford Site can be achieved with a level of onsite safety equivalent to that achieved offsite. Utilizing the parameters, requirements, limitations, and controls described in the DOE/RL-2001-36, ''Hanford Sitewide Transportation Safety Document'' (TSD) and the Department of Energy Richland Operations (DOE-RL) approved package specific authorizations (e.g. Package Specific Safety Documents (PSSDs), One-Time Requests for Shipment (OTRSs), and Special Packaging Authorizations (SPAS)), this evaluation concludes that polyurea coatings on packages does not impose an undue hazard for normal and accident conditions. The transportation of all packages on the Hanford Site must comply with the transportation safety basis documents for that packaging system. Compliance with the requirements, limitations, or controls described in the safety basis for a package system will not be relaxed or modified because of the application of polyurea. The inspection criteria described in facility/projects procedures and work packages that ensure compliance with Container Management Programs and transportation safety basis documentation dictate the need to overpack a package without consideration for polyurea. This technical report reviews the transportation of waste packages coated with polyurea and does not credit the polyurea with enhancing the structural, thermal, containment, shielding, criticality, or gas generating posture of a package. Facilities/Projects Container Management Programs must determine if a container requires an overpack prior to the polyurea application recognizing that circumstances newly discovered surface contamination or loss of integrity may require a previously

  4. Comparative Evaluation of Quantitative Test Methods for Gases on a Hard Surface

    Science.gov (United States)

    2017-02-01

    XX-02-2017 2. REPORT TYPE Final 3. DATES COVERED (From - To) Apr 2008 – Dec 2008 4. TITLE AND SUBTITLE Comparative Evaluation of...determining the efficacy of chlorine dioxide (CD) gas and vaporous hydrogen peroxide (VHP) against spores of Bacillus subtilis. The tests were...SUBJECT TERMS Three Step Method (TSM) Quantitative Carrier Disk Test (QCT) Chlorine dioxide (CD) Bacillus subtilis Vaporous hydrogen peroxide

  5. Evaluation of tribological wear and corrosion in coatings of diamalloy 4060NS deposited by thermal spray

    Science.gov (United States)

    Acuña R, S. M.; Moreno T, C. M.; Espinosa C, E. J.

    2017-12-01

    Surface engineering seeks the development of new techniques to improve the performance and life of components of machines or industrial facilities, always looking for low costs and the least possible environmental damage. Thermal projection is one of the techniques that is based on the projection of particles of compounds and alloys on properly prepared and heated substrates, these particles are driven by a stream of air passing through an oxyacetylene flame which gives the energy to the process; These coatings give the possibility to improve the properties of the materials or the maintenance of components to maximize the availability of service. In order to reduce the damage caused by wear and corrosion of a low carbon AISI 1020 steel, they were coated with a metal based alloy, studying the effect of the cobalt-chromium-silicon-tungsten carbide alloy coating (DIAMALLLOY 4060 NS). The coating was deposited with two different pressures in the gases supplied to the torch, obtaining two flames and working three thicknesses of coating that oscillate between 100-500μm, according to the number of deposited layers, making use of a projection gun Castolin Eutectic. Powder and substrate characterization was performed using X-Ray Diffraction (XRD) techniques, X-Ray Fluorescence (XRF), Scanning Electron Microscopy (SEM), spark emission spectroscopy and metallographic analysis. The results confirm the chemical nature and structure of the powder of the alloy and the substrate to be used, in addition, the thermal stability of the system was verified. The evaluation of the adhesion of the deposited layers was carried out by the implementation of pull-off tests according to ASTM D4541, in order to determine the type of failure that is presented. Mechanical wear was determined using a MT/60/NI microtest tribometer while electrochemical tests were performed using a suitable experimental unit for this purpose, confirming that the substrate exhibits lower wear levels when coated with

  6. Evaluation of Selected Properties of Alder Wood as Functions of Sanding and Coating

    Directory of Open Access Journals (Sweden)

    Emilia-Adela Salca

    2017-10-01

    Full Text Available The objective of this study was to optimize the sanding and coating processes of black alder wood to promote and support its use in furniture manufacturing. Two criteria have been applied for process optimization, namely, the minimum surface roughness of the samples and power consumption during sanding as a function of various sanding systems. The surface roughness of the sanded specimens and the power consumption during sanding strongly depends on the grit size used. Two eco-varnishes were applied to the samples by spraying. Moreover, the effect of the surface preparation and varnish type on the coating properties expressed by the varnish layer adherence to the substrate and surface glossiness was evaluated. For better glossiness values, the UV-cured varnish was preferred. The sanding with a grit sequence of 60, 120, and 150 grit size abrasives was found to be optimal when applied to black alder wood, and it is recommended to obtain performant UV-coated wood surfaces for furniture products.

  7. Preparation and evaluation of PEO-coated materials for a microchannel hemodialyzer.

    Science.gov (United States)

    Heintz, Keely; Schilke, Karl F; Snider, Joshua; Lee, Woo-Kul; Truong, Mitchell; Coblyn, Matthew; Jovanovic, Goran; McGuire, Joseph

    2014-07-01

    The marked increase in surface-to-volume ratio associated with microscale devices for hemodialysis leads to problems with hemocompatibility and blood flow distribution that are more challenging to manage than those encountered at the conventional scale. In this work stable surface modifications with pendant polyethylene oxide (PEO) chains were produced on polydimethylsiloxane (PDMS), polycarbonate microchannel, and polyacrylonitrile membrane materials used in construction of microchannel hemodialyzer test articles. PEO layers were prepared by radiolytic grafting of PEO-polybutadiene-PEO (PEO-PB-PEO) triblock polymers to the material surfaces. Protein repulsion was evaluated by measurement of surface-bound enzyme activity following contact of uncoated and PEO-coated surfaces with β-galactosidase. Protein adsorption was decreased on PEO-coated polycarbonate and PDMS materials to about 20% of the level recorded on the uncoated materials. Neither the triblocks nor the irradiation process was observed to have any effect on protein interaction with the polyacrylonitrile membrane, or its permeability to urea. This approach holds promise as a means for in situ application of safe, efficacious coatings to microfluidic devices for blood processing that will ensure good hemocompatibility and blood flow distribution, with no adverse effects on mass transfer. © 2013 Wiley Periodicals, Inc.

  8. Synthesis and evaluation of polystyrene-polybutadiene-polystyrene-dodecafluoroheptyl methacrylate/polystyrene-polybutadiene-polystyrene hybrid antifouling coating.

    Science.gov (United States)

    Li, Jiang; Wang, Guoqing; Ding, Chunhua; Jiang, Hong; Wang, Peiqing

    2014-11-15

    Copolymers SBS-DFHMA and mesoporous silica SBA-15 were respectively synthesized and SBS-DFHMA were mixed with SBA-15 to prepared hybrid antifouling coatings by a spin-coater. By measuring the surface water contact angle and the attachment of Pseudomonas fluorescens, Chlorella and Diatoms, the antifouling properties of coatings were evaluated. The results shown that the surface of hybrid coatings, the water contact angle arrived 120°, were more hydrophobic than the SBS-DFHMA coatings. In terms of resistance of adhesion, low surface energy coatings of SBS-DFHMA could effectively weaken the adhesion behavior of P.fluorescens and Diatoms, but the role to Chlorella was not obvious. When 0.01 g/ml SBA-15 was added, the adhesion of three marine microorganisms all had a very significant decrease to the hybrid coatings. These indicated that the fluorinated low surface energy antifouling coatings had limitation on resisting Chlorella attaching, and the addition of SBA-15 not only enhanced the ability of resistance to adhesion but also widen the applicability to more fouling and narrowed its limitations. This surprising effect was due to micro-nano convex structure of the coatings surface caused by hybrid. Copyright © 2014. Published by Elsevier Inc.

  9. Fluorescence microscopy techniques for quantitative evaluation of organic biocide distribution in antifouling paint coatings: Application to model antifouling coatings

    NARCIS (Netherlands)

    Goodes, L.R.; Dennington, S.P.; Schuppe, H.; Wharton, J.A.; Bakker, M.; Klijnstra, J.W.; Stokes, K.R.

    2012-01-01

    A test matrix of antifouling (AF) coatings including pMMA, an erodible binder and a novel trityl copolymer incorporating Cu 2O and a furan derivative (FD) natural product, were subjected to pontoon immersion and accelerated rotor tests. Fluorescence and optical microscopy techniques were applied to

  10. The Characterisation and Performance of Magnetron Sputter Coatings on Minting Dies

    Science.gov (United States)

    McLean, David Alexander

    Enhancing the performance of various tools and mechanical parts through the use of thin films has been given much attention recently. Thin films have many different uses including: reducing friction, protecting from corrosion and increasing hardness and wear resistance. The Royal Canadian Mint has adopted the magnetron sputter ion plating technique to apply a new Cr-Ti-N based multi-component hard coating and thereby replace their Cr-plating process. Apart from showing improvements to the performance of their minting dies, this change is also more environmentally friendly. The purpose of this thesis is to further characterise this new coating which has shown superior performance. The structure of coatings applied using the magnetron sputter ion plating technique was reviewed along with the hardness and performance analysis of thin-film coatings. Hardness performance of the film on minting dies, including hardness testing and thin-film hardness models, are reviewed. The die performance is discussed in terms of surface wear encountered during the minting process. Two test dies made from air-hardening tool steel are coated and analysed for their hardness performance. Three numismatic coin dies are also analysed at different stages of their lifetime to compare the surface wear at those stages and evaluate the performance of the coating. Both nano- and micro-indentation hardness testing was used to obtain hardness data on the two test dies. The Korsunsky thin-film hardness model was selected to best represent both sets of hardness data. The thin-film hardness model parameters and film hardness were simultaneously calibrated using both nano- and micro-indentation test data. The film hardness was determined to be about 2672 HV. The film hardness was then successfully predicted using only the micro-indentation data and the method was demonstrated on two additional dies with the same composition. The hardness performance of the die was linked to the adhesion of the film. In

  11. Evaluating the effect of coating equipment on tablet film quality using terahertz pulsed imaging

    DEFF Research Database (Denmark)

    Haaser, Miriam; Naelapaa, Kaisa; Gordon, Keith C

    2013-01-01

    In this study, terahertz pulsed imaging (TPI) was employed to investigate the effect of the coating equipment (fluid bed and drum coater) on the structure of the applied film coating and subsequent dissolution behaviour. Six tablets from every batch coated with the same delayed release coating fo...

  12. Effect of the metal concentration on the structural, mechanical and tribological properties of self-organized a-C:Cu hard nanocomposite coatings

    Energy Technology Data Exchange (ETDEWEB)

    Pardo, A., E-mail: ainhoa.pardo@ctm.com.es [Fundació CTM Centre Tecnològic, Manresa (Spain); Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC) (Spain); Buijnsters, J.G., E-mail: Ivan.Buijnsters@mtm.kuleuven.be [Department of Metallurgy and Materials Engineering, KU Leuven, Leuven (Belgium); Endrino, J.L., E-mail: jose.endrino@research.abengoa.com [Abengoa Research, Sevilla (Spain); Gómez-Aleixandre, C., E-mail: cgaleix@icmm.csic.es [Instituto de Ciencia de Materiales de Madrid (ICMM-CSIC) (Spain); Abrasonis, G., E-mail: g.abrasonis@hzdr.de [Institute of Ion Beam Physics and Materials Research, Dresden (Germany); Bonet, R., E-mail: raul.bonet@ctm.com.es [Fundació CTM Centre Tecnològic, Manresa (Spain); Caro, J., E-mail: jaume.caro@ctm.com.es [Fundació CTM Centre Tecnològic, Manresa (Spain)

    2013-09-01

    The influence of the metal content (Cu: 0–28 at.%) on the structural, mechanical and tribological properties of amorphous carbon films grown by pulsed filtered cathodic vacuum arc deposition is investigated. Silicon and AISI 301 stainless steel have been used as substrate materials. The microstructure, composition and bonding structure have been determined by scanning electron microscopy, combined Rutherford backscattered spectroscopy-nuclear reaction analysis, and Raman spectroscopy, respectively. The mechanical and tribological properties have been assessed using nanoindentation and reciprocating sliding (fretting tests) and these have been correlated with the elemental composition of the films. A self-organized multilayered structure consisting of alternating carbon and copper metal nanolayers (thickness in the 25–50 nm range), whose formation is enhanced by the Cu content, is detected. The nanohardness and Young’s modulus decrease monotonically with increasing Cu content. A maximum value of the Young’s modulus of about 255 GPa is obtained for the metal-free film, whereas it drops to about 174 GPa for the film with a Cu content of 28 at.%. In parallel, a 50% drop in the nanohardness from about 28 GPa towards 14 GPa is observed for these coatings. An increase in the Cu content also produces an increment of the coefficient of friction in reciprocating sliding tests performed against a corundum ball counterbody. As compared to the metal free film, a nearly four times higher coefficient of friction value is detected in the case of a Cu content of 28 at.%. Nevertheless, the carbon–copper composite coatings produced a clear surface protection of the substrate despite an overall increase in wear loss with increasing Cu content in the range 3–28 at.%.

  13. Experimental Evaluation And Simulation Of Multi-pixel Cadmium-zinc-telluride Hard-x-ray Detectors

    CERN Document Server

    Gaskin, J A

    2004-01-01

    This dissertation describes the evaluation of many-pixel Cadmium-Zinc-Telluride (CdZnTe) hard-X-ray detectors for future use with the High Energy Replicated Optics (HERO) telescope being developed at Marshall Space Flight Center. The detector requirements for the HERO application are good energy resolution (sufficient to resolve cyclotron features and nuclear lines), spatial resolution of ∼200 μm, minimal charge loss of absorbed X rays, and minimal sensitivity to the background environment. This research concentrates on assessing the suitability of these detectors for the focus of HERO, and includes the development of a simulation of the physics involved in an X-ray-detector interaction, a study of the intrinsic material properties, measurements with prototype detectors such as the energy and spatial resolution, charge loss, and X-ray background reduction through 3-dimensional depth sensing. Two types of detectors were available for evaluation. The first type includes 1-mm and 2-mm thick 4 x 4 ...

  14. Hardness evaluation of cured urea-formaldehyde resins with different formaldehyde/urea mole ratios using nanoindentation method

    Science.gov (United States)

    Byung-Dae Park; Charles R. Frihart; Yan Yu; Adya P. Singh

    2013-01-01

    To understand the influence of formaldehyde/urea (F/U) mole ratio on the properties of urea–formaldehyde (UF) resins, this study investigated hardness of cured UF resins with different F/U mole ratios using a nanoindentation method. The traditional Brinell hardness (HB) method was also used...

  15. Evaluation of atmospheric corrosion on electroplated zinc and zinc nickel coatings by Electrical Resistance (ER) Monitoring

    DEFF Research Database (Denmark)

    Møller, Per

    2013-01-01

    ER (Electrical Resistance) probes provide a measurement of metal loss, measured at any time when a metal is exposed to the real environment. The precise electrical resistance monitoring system can evaluate the corrosion to the level of nanometers, if the conductivity is compensated for temperature...... and magnetic fields. With this technique very important information about the durability of a new conversion coatings for aluminum, zinc and zinc alloys exposed to unknown atmospheric conditions can be gathered. This is expected to have a major impact on a number of industrial segments, such as test cars...

  16. Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period

    Directory of Open Access Journals (Sweden)

    Ugur Erdemir

    2013-04-01

    Full Text Available Objectives: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. Material and Methods: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group. For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05. Results: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (p<0.001 in different solutions (p<0.001. The effect of different solutions on the surface hardness values of the restorative materials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (p<0.001. The compomer was the most affected by an acidic environment, whereas the composite resin materials were the least affected materials. Conclusions: The effect of sports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material.

  17. Experimental investigation on erosive wear behaviour of plasma spray coated stainless steel

    Science.gov (United States)

    Girisha, K. G.; Sreenivas Rao, K. V.; Anil, K. C.; Sanman, S.

    2017-04-01

    Slurry erosion is an implicit problem in many engineering industrial components such as ore carrying pipelines, slurry pumps and extruders. Even the water turbine blades are subjected to erosive wear when the water contains considerable amount of silt. In the present study, Al2O3-40%TiO2 powder particles of average particle size of 50 micrometer were deposited on EN56B martenistic stainless steel by atmospheric plasma spray technique. Ni/Cr was pre coated to work as bond coat for good adhesion between coating and the substrate material. A coating thickness of 200 micrometer was achieved. Coated and un-coated substrates were subjected to slurry erosion test as per ASTM G-119 standard. Slurry erosion test rig was used to evaluate the erosion properties at room temperature condition by varying the spindle speed. Scanning electron microphotographs were taken before and after the slurry erosion test. Microstructures reveal uniform distribution of coating materials. Eroded surface shows lip, groove, and crater formation and dense coating resulting in less porosity. Micro hardness test was evaluated and reported. EDX analysis confirms the presence of Al, Ti and O2 particles. It was observed that, Al2O3-40%TiO2 coated substrates exhibit superior erosion resistance as compared to un-coated substrates due to higher hardness and less coating porosity.

  18. A histologic evaluation of retrieved hydroxyapatite-coated blade-form implants using scanning electron, light, and confocal laser scanning microscopies.

    Science.gov (United States)

    Takeshita, F; Ayukawa, Y; Iyama, S; Suetsugu, T; Kido, M A

    1996-10-01

    We histologically examined seven hydroxyapatite-coated (HA) blade implants removed from patients. Four of them radiologically showed severe bone loss and were easily removed with an elevator. Three radiologically showed vertical bone loss and were removed by surgical procedure. Our histological evaluation indicated that coating separation from the HA implants had occurred, and HA coating resorption by bone tissues was suspected in an implant left in situ for 8 years. Several multinucleated giant cells were seen with a few released particles of HA coating at the point lacking bone contact with the HA coating. The presence of microorganisms on and in the HA coating layer was also noted.

  19. Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period.

    Science.gov (United States)

    Erdemir, Ugur; Yildiz, Esra; Eren, Meltem Mert; Ozel, Sevda

    2013-01-01

    This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group). For the control groups, the specimens were stored in distilled water for 24 hours at 37°C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05). Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (psports and energy drinks after a 1-month evaluation period (psports and energy drinks on the surface hardness of a restorative material depends on the duration of exposure time, and the composition of the material.

  20. Comparative characterization of Cu–Ni substrates for coated conductors

    DEFF Research Database (Denmark)

    Tian, H.; Suo, H.L.; Wulff, Anders Christian

    2014-01-01

    Three Cu100xNix alloys, with x = 23, 33 and 45 at.%Ni, have been evaluated for use as substrates for coated conductors on the basis of measurements of their microstructure, crystallographic texture and hardness. It is found that high-temperature annealing after heavy rolling generates strong cube...

  1. Comparative assessment of coated and uncoated ceramic tools on ...

    Indian Academy of Sciences (India)

    This study investigated the cutting performance of coated CC6050 and uncoated CC650 mixed ceramics in hard turning of hardened steel. The cutting performance was mainly evaluated by cutting force components and tool wear. The planning of experiments was based on Taguchi's L36 orthogonal array. Theresponse ...

  2. Color and gloss evaluation of titanium dioxide coating for acrylic resin denture base.

    Science.gov (United States)

    Mori, Kazunari; Tsuji, Masashi; Ueda, Takayuki; Sakurai, Kaoru

    2015-10-01

    We examined the clinical appearance (color, gloss, and surface roughness) of TiO(2) coating on polymethyl methacrylate (PMMA) resin dentures. A spraying method, using air brushes, was used to generate thin uniform TiO(2) coating. PMMA resin, primer-coated PMMA, and TiO(2)-coated PMMA (with primer) specimens were compared. The Commission Internationale de l'Eclairage (CIE) color system revealed color variations between the with/without coated samples. The TiO(2)-coated PMMA specimen displayed high levels of glossiness, highlighting the efficient self-cleansing actions of the denture. The measured surface roughness decreased upon primer coating, and increased following TiO(2) coating. The thin TiO(2) coating afforded high levels of glossiness while maintaining the color of the denture base material. Copyright © 2015 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  3. Compaction of enteric-coated pellets: influence of formulation and process parameters on tablet properties and in vivo evaluation.

    Science.gov (United States)

    Debunne, Ann; Vervaet, Chris; Mangelings, Debby; Remon, Jean-Paul

    2004-07-01

    The aim of this study was to investigate the influence of formulation and compression parameters on the properties of tablets, containing enteric-coated pellets, and on the integrity of the enteric polymer of the individual pellets after compression. In addition the piroxicam plasma concentrations were determined after single and multiple oral administration of powder, pellet and tablet formulations at a dose of 0.3 mg piroxicam/kg bodyweight to dogs. Tablets consisted of enteric-coated pellets (containing 2.5% (w/w) piroxicam in combination with microcrystalline cellulose and sodium carboxymethylcellulose (using Avicel PH 101 and Avicel CL 611 in a ratio of 1-3), cushioning waxy pellets and 10% Kollidon CL (as an external disintegrator). From the D-optimality experimental design it was concluded that the ratio of coated pellets to cushioning pellets (CoP/CuP) affected all tablet properties evaluated. Variation of the pellet size and the CoP/CuP ratio resulted in different in vitro tablet disintegration times. Enteric coating of the pellets or compression of the coated pellets did not have a significant influence (P >0.05) on AUC(0-->72 h). Cmax values obtained after oral administration of coated pellets and compressed coated pellets were significantly lower than for the other formulations. Differences in in vitro tablet disintegration times were not reflected in the onset of the piroxicam plasma concentrations. A dosing interval of 48 h prevented piroxicam accumulation following multiple dose administration.

  4. Nondestructive Evaluation of Flaking-Resistance in Thermal Sprayed Ceramic Coatings with X-ray Diffraction Method

    Science.gov (United States)

    Ito, Toru; Kubohori, Toshifumi; Morimoto, Jyunji

    Thermal spraying has emerged as an important tool of increasingly sophisticated surface engineering technology. Therefore, the demand for technology that is checked non-destructively has become more insistent. This paper presents the nondestructive evaluation of fl aking-resistance in thermal sprayed Al2O3, ZrO2 and TiO2 coating. The full-width at half maximum taken from the X-ray diffraction peak profi le was used as a nondestructive evaluation method in this study. The results by the nondestructive method were compared to the results with scratch test. It was found that nondestructive evaluation of the thermal sprayed ceramic coating was effective.

  5. Material Evaluation and Process Optimization of CNT-Coated Polymer Powders for Selective Laser Sintering

    Directory of Open Access Journals (Sweden)

    Shangqin Yuan

    2016-10-01

    Full Text Available Multi-walled carbon nanotubes (CNTs as nano-reinforcements were introduced to facilitate the laser sintering process and enhance the thermal and mechanical properties of polymeric composites. A dual experimental-theoretical method was proposed to evaluate the processability and predict the process parameters of newly developed CNT-coated polyamide 12 (CNTs/PA12 powders. The thermal conductivity, melt viscosity, phase transition and temperature-dependent density and heat capacity of PA12 and CNTs/PA12 powders were characterized for material evaluation. The composite powders exhibited improved heat conduction and heat absorption compared with virgin polymer powders, and the stable sintering range of composite powders was extended and found to be favourable for the sintering process. The microstructures of sintered composites revealed that the CNTs remained at the powder boundaries and formed network architectures, which instantaneously induced the significant enhancements in tensile strength, elongation at break and toughness without sacrificing tensile modulus.

  6. Evaluation in a Dog Model of Three Antimicrobial Glassy Coatings: Prevention of Bone Loss around Implants and Microbial Assessments.

    Science.gov (United States)

    López-Píriz, Roberto; Solá-Linares, Eva; Rodriguez-Portugal, Mercedes; Malpica, Beatriz; Díaz-Güemes, Idoia; Enciso, Silvia; Esteban-Tejeda, Leticia; Cabal, Belén; Granizo, Juan José; Moya, José Serafín; Torrecillas, Ramón

    2015-01-01

    The aim of the present study is to evaluate, in a ligature-induced peri-implantitis model, the efficacy of three antimicrobial glassy coatings in the prevention of biofilm formation, intrasulcular bacterial growth and the resulting peri-implant bone loss. Mandibular premolars were bilaterally extracted from five beagle dogs. Four dental implants were inserted on each hemiarch. Eight weeks after, one control zirconia abutment and three with different bactericidal coatings (G1n-Ag, ZnO35, G3) were connected. After a plaque control period, bacterial accumulation was allowed and biofilm formation on abutments was observed by Scanning Electron Microscopy (SEM). Peri-implantitis was induced by cotton ligatures. Microbial samples and peri-implant crestal bone levels of all implant sites were obtained before, during and after the breakdown period. During experimental induce peri-implantitis: colony forming units counts from intrasulcular microbial samples at implants with G1n-Ag coated abutment remained close to the basal inoculum; G3 and ZnO35 coatings showed similar low counts; and anaerobic bacterias counts at control abutments exhibited a logarithmic increase by more than 2. Bone loss during passive breakdown period was no statistically significant. Additional bone loss occurred during ligature-induce breakdown: 0.71 (SD 0.48) at G3 coating, 0.57 (SD 0.36) at ZnO35 coating, 0.74 (SD 0.47) at G1n-Ag coating, and 1.29 (SD 0.45) at control abutments; and statistically significant differences (p<0.001) were found. The lowest bone loss at the end of the experiment was exhibited by implants dressing G3 coated abutments (mean 2.1; SD 0.42). Antimicrobial glassy coatings could be a useful tool to ward off, diminish or delay peri-implantitis progression.

  7. Evaluation in a Dog Model of Three Antimicrobial Glassy Coatings: Prevention of Bone Loss around Implants and Microbial Assessments.

    Directory of Open Access Journals (Sweden)

    Roberto López-Píriz

    Full Text Available The aim of the present study is to evaluate, in a ligature-induced peri-implantitis model, the efficacy of three antimicrobial glassy coatings in the prevention of biofilm formation, intrasulcular bacterial growth and the resulting peri-implant bone loss.Mandibular premolars were bilaterally extracted from five beagle dogs. Four dental implants were inserted on each hemiarch. Eight weeks after, one control zirconia abutment and three with different bactericidal coatings (G1n-Ag, ZnO35, G3 were connected. After a plaque control period, bacterial accumulation was allowed and biofilm formation on abutments was observed by Scanning Electron Microscopy (SEM. Peri-implantitis was induced by cotton ligatures. Microbial samples and peri-implant crestal bone levels of all implant sites were obtained before, during and after the breakdown period.During experimental induce peri-implantitis: colony forming units counts from intrasulcular microbial samples at implants with G1n-Ag coated abutment remained close to the basal inoculum; G3 and ZnO35 coatings showed similar low counts; and anaerobic bacterias counts at control abutments exhibited a logarithmic increase by more than 2. Bone loss during passive breakdown period was no statistically significant. Additional bone loss occurred during ligature-induce breakdown: 0.71 (SD 0.48 at G3 coating, 0.57 (SD 0.36 at ZnO35 coating, 0.74 (SD 0.47 at G1n-Ag coating, and 1.29 (SD 0.45 at control abutments; and statistically significant differences (p<0.001 were found. The lowest bone loss at the end of the experiment was exhibited by implants dressing G3 coated abutments (mean 2.1; SD 0.42.Antimicrobial glassy coatings could be a useful tool to ward off, diminish or delay peri-implantitis progression.

  8. In vitro evaluation of topical fluoride pH and their effect on surface hardness of composite resin-based restorative materials.

    Science.gov (United States)

    Mujeeb, Abdul; Mansuri, Samir; Hussain, Seema Abid; Ramaswamy, Kausar

    2014-03-01

    The aim of the study was to correlate the pH and fluoride ion uptake with surface hardness of composite resin based restorative materials after topical fluoride application. Forty disks of each of test materials Composite (Filtek Z350XT, 3M ESPE, St Paul, MN, USA), Resin modified glass ionomer (Vitremer) and Compomer (Dyract AP) were made and ten disks of each material were placed in different test solutions - 1.23% APF gel, Sodium fluoride mouth rinse, 0.9% neutral fluoride and distilled water (Control group). After 36 hours of immersion, specimens were subjected to microhardness testing machine for evaluation of surface hardness. The greater hardness deterioration for all materials resulted with 1.23% APF gel when compared to the control group. Composite (Filtek Z350XT, 3M ESPE, St Paul, MN, USA) showed 17.13 VHN (control group 59.11 VHN). Vitremer showed 9.71 VHN (control group 37.71 VHN). Compomer showed 19.22 VHN (control group 36.78 VHN). 1.23% ApF gel significantly decreased hardness of composite, Vitremer and Compomer. Hardness deterioration associated with sodium fluoride mouth rinse and 0.9% neutral fluoride was less compared to 1.23% ApF gel.

  9. Development of coatings for ultrasonic additive manufacturing sonotrode using laser direct metal deposition process

    Energy Technology Data Exchange (ETDEWEB)

    Niyanth S, Niyanth [ORNL; Dehoff, Ryan R [ORNL; Jordan, Brian H [ORNL; Babu, Sudarsanam Suresh [ORNL

    2016-10-01

    ORNL partnered with Fabrisonic, LLC to develop galling resistant hard facing coatings on sonotrodes used to fabricate 3D printed materials using ultrasonic additive manufacturing. The development and deployment of a coated sonotrode is expected to push the existing state of the art to facilitate the solidstate additive manufacturing of hard steels and titanium alloys. To this effect a structurally amorphous stainless steel material and cobalt chrome material were deposited on the sonotrode material. Both the deposits showed good adhesion to the substrate. The coatings made using the structurally amorphous steel materials showed cracking during the initial trials and cracking was eliminated by deposition on a preheated substrate. Both the coatings show hardness in excess of 600 HVN. Thus the phase 1 of this project has been used to identify suitable materials to use to coat the sonotrode. Despite the fact that successful deposits were obtained, the coatings need to be evaluated by performing detailed galling tests at various temperatures. In addition field tests are also necessary to test the stability of these coatings in a high cycle ultrasonic vibration mode. If awarded, phase 2 of the project would be used to optimize the composition of the deposit material to maximize galling resistance. The industrial partner would then use the coated sonotrode to fabricate builds made of austenitic stainless steel to test the viability of using a coated sonotrode.

  10. EVALUATION OF THE EFFECTIVENESS OF COATINGS IN REDUCING DISLODGEABLE ARSENIC, CHROMIUM, AND COPPER FROM CCA TREATED WOOD; FINAL REPORT

    Science.gov (United States)

    EPA conducted a study to evaluate the effect of coatings on dislodgeable arsenic, chromium, and copper residues on the surfaces of chromated copper arsenate (CAA) treated wood. Dislodgeable CCA, determined by wipe sampling the wood surfaces, was the primary evaluation criterion f...

  11. Analytical and Experimental Draft Force Evaluation of Plastic Coated Chisel Tines

    Directory of Open Access Journals (Sweden)

    M Barzegar Tabrizi

    2017-10-01

    Methods Eight tines have been built. Four of them had a thick coating layer of UHMW-PE, and the other four were made of pure mild steel. Each set of the tines have been installed on a four shanked chisel plough chassis and then attached to a tractor. The draft force required for pulling the furrowers attached to the tractor has been measured by a simple load meter mechanism connecting two tractors. Draft force has been measured in two different speeds. Slip ratio of the tractor has been recorded. Each test has been repeated three times.McKyes-Ali’s proposed model for evaluating the draft force of narrow blades has been chosen to predict draft force of the traditional steel furrower tines and the surface coated ones. To drive the model, a computer program has been coded in the script environment of Matlab software. The model required some of the mechanical properties of the soil and the tool to operate. Specific gravity, cohesion and internal friction angle of the soil have been measured by routine laboratory methods. Soil-tool adhesion and friction of the mild steel and the UHMW-PE plates have been measured using the direct shear apparatus. Results and Discussions MkKyes-Ali’s model has predicted draft forces with an accuracy of 90%. According to the results of the driven model, applying a UHMW-PE coating layer to the surface of the tines can improve draft force by 13%. The change of tractor speed from 3.5 km h-1 to 5.5 km h-1 have no significant effect on the predicted draft forces. The model also predicted different angles of the soil failure zone for coated and uncoated tines. On the other hand, the improvement of the draft force for the UHMW-PE coated tine in the field test was about 27%. According to The results obtained from the field test, the draft force of the furrower tines had significant correlation with the speed. Conclusions The UHMW-PE coated tines required significantly less draft force to work in compare with the steel tines. McKyes-Ali’s model

  12. [Emission characteristics and safety evaluation of volatile organic compounds in manufacturing processes of automotive coatings].

    Science.gov (United States)

    Zeng, Pei-Yuan; Li, Jian-Jun; Liao, Dong-Qi; Tu, Xiang; Xu, Mei-Ying; Sun, Guo-Ping

    2013-12-01

    Emission characteristics of volatile organic compounds (VOCs) were investigated in an automotive coating manufacturing enterprise. Air samples were taken from eight different manufacturing areas in three workshops, and the species of VOCs and their concentrations were measured by gas chromatography-mass spectrometry (GC-MS). Safety evaluation was also conducted by comparing the concentration of VOCs with the permissible concentration-short term exposure limit (PC-STEL) regulated by the Ministry of Health. The results showed that fifteen VOCs were detected in the indoor air of the automotive coatings workshop, including benzene, toluene, ethylbenzene, xylene, ethyl acetate, butyl acetate, methyl isobutyl ketone, propylene glycol monomethyl ether acetate, trimethylbenzene and ethylene glycol monobutyl ether, Their concentrations widely ranged from 0.51 to 593.14 mg x m(-3). The concentrations of TVOCs were significantly different among different manufacturing processes. Even in the same manufacturing process, the concentrations of each component measured at different times were also greatly different. The predominant VOCs of indoor air in the workshop were identified to be ethylbenzene and butyl acetate. The concentrations of most VOCs exceeded the occupational exposure limits, so the corresponding control measures should be taken to protect the health of the workers.

  13. In vitro evaluation of novel polymer-coated magnetic nanoparticles for controlled drug delivery

    Science.gov (United States)

    Rahimi, Maham; Wadajkar, Aniket; Subramanian, Khaushik; Yousef, Monet; Cui, Weina; Hsieh, Jer-Tsong; Nguyen, Kytai

    2010-01-01

    Previously uncharacterized poly(N-isopropylacrylamide-acrylamide-allylamine)-coated magnetic nanoparticles (MNPs) were synthesized using silane-coated MNPs as a template for radical polymerization of N-isopropylacrylamide, acrylamide, and allylamine. Properties of these nanoparticles such as size, biocompatibility, drug loading efficiency, and drug release kinetics were evaluated in vitro for targeted and controlled drug delivery. Spherical core-shell nanoparticles with a diameter of 100 nm showed significantly lower systemic toxicity than did bare MNPs, as well as doxorubicin encapsulation efficiency of 72%, and significantly higher doxorubicin release at 41°C compared with 37°C, demonstrating their temperature sensitivity. Released drugs were also active in destroying prostate cancer cells (JHU31). Furthermore, the nanoparticle uptake by JHU31 cells was dependent on dose and incubation time, reaching saturation at 500 μg/mL and 4 hours, respectively. In addition, magnetic resonance imaging capabilities of the particles were observed using agarose platforms containing cells incubated with nanoparticles. Future work includes investigation of targeting capability and effectiveness of these nanoparticles in vivo using animal models. PMID:20172050

  14. Standard Test Method for Mechanical Hydrogen Embrittlement Evaluation of Plating/Coating Processes and Service Environments

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2010-01-01

    1.1 This test method describes mechanical test methods and defines acceptance criteria for coating and plating processes that can cause hydrogen embrittlement in steels. Subsequent exposure to chemicals encountered in service environments, such as fluids, cleaning treatments or maintenance chemicals that come in contact with the plated/coated or bare surface of the steel, can also be evaluated. 1.2 This test method is not intended to measure the relative susceptibility of different steels. The relative susceptibility of different materials to hydrogen embrittlement may be determined in accordance with Test Method F1459 and Test Method F1624. 1.3 This test method specifies the use of air melted AISI E4340 steel per SAE AMS-S-5000 (formerly MIL-S-5000) heat treated to 260 – 280 ksi (pounds per square inch x 1000) as the baseline. This combination of alloy and heat treat level has been used for many years and a large database has been accumulated in the aerospace industry on its specific response to exposure...

  15. Evaluation by extended Hückel method on the hardness of the B–C–N materials

    Directory of Open Access Journals (Sweden)

    Hideaki Takashima and Yoshinori Kanno

    2005-01-01

    Full Text Available Hard materials, e.g. diamond and cubic boron nitride (c-BN, are widely applied to improve the lifetime and the performance of many kinds of cutting and forming tools. These materials are usually used at high temperature, so the study of stability on these materials at high temperature is very important. However, diamond is a low resistance to the oxidation, it should be replaced with the boron-based hard materials. Recently, boron–carbon–nitrogen (B–C–N ternary materials are expected to possess a high hardness, a high thermal stability at high temperature. We estimated the hardness and the stability of B–C–N materials at high temperature by the extended Hückel method. The extended Hückel method is one of the molecular orbital calculations and needs the cluster model of materials for the calculation. The cluster model of B–C–N materials was regarded as a zinc blende structure. In the present work, we used two physical quantities, i.e. a cohesive energy and an energy fluctuation, as a measure of hardness and stability of materials. The cohesive energy indicates the coherence of bonds between atoms. The energy fluctuation shows the reactivity of materials. Hardness, structure, solid-state properties and reactivity of materials can be estimated from these physical quantities. When the composition of B–C–N materials was boron: 25 at.%, nitrogen: 25 at.% and carbon: 50 at.%, the cohesive energy was the lowest. This result implies B–C–N ternary materials are not harder than c-BN and/or diamond. Cubic-BN was the lowest energy fluctuation of B–C–N materials, and the energy fluctuation increased as increasing of carbon atom. The reactivity of B–C–N materials was high at a high temperature with an increase of carbon atoms. These results imply that B–C–N materials are not suitable for the hard cutting materials.

  16. Comparison of Analytic Hierarchy Process, Catastrophe and Entropy techniques for evaluating groundwater prospect of hard-rock aquifer systems

    Science.gov (United States)

    Jenifer, M. Annie; Jha, Madan K.

    2017-05-01

    Groundwater is a treasured underground resource, which plays a central role in sustainable water management. However, it being hidden and dynamic in nature, its sustainable development and management calls for precise quantification of this precious resource at an appropriate scale. This study demonstrates the efficacy of three GIS-based multi-criteria decision analysis (MCDA) techniques, viz., Analytic Hierarchy Process (AHP), Catastrophe and Entropy in evaluating groundwater potential through a case study in hard-rock aquifer systems. Using satellite imagery and relevant field data, eight thematic layers (rainfall, land slope, drainage density, soil, lineament density, geology, proximity to surface water bodies and elevation) of the factors having significant influence on groundwater occurrence were prepared. These thematic layers and their features were assigned suitable weights based on the conceptual frameworks of AHP, Catastrophe and Entropy techniques and then they were integrated in the GIS environment to generate an integrated raster layer depicting groundwater potential index of the study area. The three groundwater prospect maps thus yielded by these MCDA techniques were verified using a novel approach (concept of 'Dynamic Groundwater Potential'). The validation results revealed that the groundwater potential predicted by the AHP technique has a pronounced accuracy of 87% compared to the Catastrophe (46% accuracy) and Entropy techniques (51% accuracy). It is concluded that the AHP technique is the most reliable for the assessment of groundwater resources followed by the Entropy method. The developed groundwater potential maps can serve as a scientific guideline for the cost-effective siting of wells and the effective planning of groundwater development at a catchment or basin scale.

  17. An in vitro evaluation of novel NHA/zircon plasma coating on 316L stainless steel dental implant

    Directory of Open Access Journals (Sweden)

    Ebrahim Karamian

    2014-04-01

    Full Text Available The surface characteristics of an implant that influence the speed and strength of osseointegration include crystal structure and bioactivity. The aim of this study was to evaluate the bioactivity of a novel natural hydroxyapatite/zircon (NHA/zircon nanobiocomposite coating on 316L stainless steel (SS dental implants soaking in simulated body fluid. A novel NHA/zircon nanobiocomposite was fabricated with 0 (control, 5, 10, and 15 wt% of zircon in NHA using ball mill for 1 h. The composite mixture was coated on SS implants using a plasma spray method. Scanning electron microscopy (SEM was used to evaluate surface morphology, and X-ray diffraction (XRD was used to analyze phase composition and crystallinity (Xc. Further, calcium ion release was measured to evaluate the coated nanobiocomposite samples. The prepared NHA/zircon coating had a nanoscale morphological structure with a mean crystallite size of 30–40 nm in diameter and a bone-like composition, which is similar to that of the biological apatite of a bone. For the prepared NHA powder, high bioactivity was observed owing to the formation of apatite crystals on its surface. Both minimum crystallinity (Xc=41.1% and maximum bioactivity occurred in the sample containing 10 wt% of zircon because of minimum Xc and maximum biodegradation of the coating sample.

  18. Effect of topical fluoride application on enamel after in-office bleaching, as evaluated using a novel hardness tester and a transverse microradiography method.

    Science.gov (United States)

    Fukuyama, Mai; Kawamoto, Chiharu; Saikaew, Pipop; Matsuda, Yasuhiro; Carvalho, Ricardo M; Selimovic, Denis; Sano, Hidehiko

    2017-12-01

    This study evaluated the effect of topical fluoride application on enamel hardness after in-office bleaching. Twelve human incisors were cut along the long axis, resulting in 24 halves used in four treatment groups (n = 6 in each group): (i) untreated group (C); (ii) in-office bleaching material (B); (iii) treatment with surface reaction-type prereacted glass-ionomer varnish after in-office bleaching (B+PRG); and (iv) treatment with acidulated phosphate fluoride solution after bleaching (B+F). All specimens were subjected to pH-cycling for 4 wk. Knoop hardness was measured using a Cariotester. The decalcification of enamel was assessed quantitatively by measuring the integrated mineral loss (ΔIML). Games-Howell analysis was used to assess statistical significance of between-group differences. The Knoop hardness decreased significantly after bleaching for all groups. In treatment groups B+PRG and B+F, the Knoop hardness returned to the original unbleached values after the first pH cycle and did not change afterwards. In treatment groups C and B there was a gradual decrease in the Knoop hardness until the fourth pH cycle. The integrated mineral loss, ΔIML, was significantly higher in treatment group B+F after 2 wk than in the other treatment groups. After 4 wk, the ΔIML in treatment group B was significantly higher than in treatment group B+PRG. The application of fluoride-containing materials after bleaching results in recuperation of hardness to levels similar to those of unbleached enamel. © 2017 Eur J Oral Sci.

  19. Development and evaluation of two PVD-coated β-titanium orthodontic archwires for fluoride-induced corrosion protection.

    Science.gov (United States)

    Krishnan, Vinod; Krishnan, Anand; Remya, R; Ravikumar, K K; Nair, S Asha; Shibli, S M A; Varma, H K; Sukumaran, K; Kumar, K Jyothindra

    2011-04-01

    The present research was aimed at developing surface coatings on β titanium orthodontic archwires capable of protection against fluoride-induced corrosion. Cathodic arc physical vapor deposition PVD (CA-PVD) and magnetron sputtering were utilized to deposit thin films of titanium aluminium nitride (TiAlN) and tungsten carbide/carbon (WC/C) coatings on β titanium orthodontic archwires. Uncoated and coated specimens were immersed in a high fluoride ion concentration mouth rinse, following a specially designed cycle simulating daily use. All specimens thus obtained were subjected to critical evaluation of parameters such as electrochemical corrosion behaviour, surface analysis, mechanical testing, microstructure, element release, and toxicology. The results confirm previous research that β titanium archwires undergo a degradation process when in contact with fluoride mouth rinses. The study confirmed the superior nature of the TiAlN coating, evident as many fewer changes in properties after fluoride treatment when compared with the WC/C coating. Thus, coating with TiAlN is recommended in order to reduce the corrosive effects of fluorides on β titanium orthodontic archwires. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  20. In vitro and in vivo evaluation of the bioactivity of hydroxyapatite-coated polyetheretherketone biocomposites created by cold spray technology.

    Science.gov (United States)

    Lee, Jae Hyup; Jang, Hae Lin; Lee, Kyung Mee; Baek, Hae-Ri; Jin, Kyoungsuk; Hong, Kug Sun; Noh, Jun Hong; Lee, Hyun-Kyung

    2013-04-01

    Polyetheretherketone (PEEK) is a material that is widely used in medicine because its mechanical properties show excellent similarity to those of human bone. However, because it is bioinert, PEEK shows limited ability to bind to natural bone tissue. Here, we applied a cold spray method to make a hydroxyapatite (HA)-coated PEEK hybrid material and evaluated its osteointegration in vitro and in vivo. With the cold spray method, the HA coating formed a homogeneous layer and adhered strongly to the PEEK disk implant. When the material was tested in vitro, early cell adhesion and viability improved. Alkaline phosphatase (ALP) activity and calcium concentration were also higher in cells cultured on HA-coated PEEK disks. In addition, the expression of osteoblast differentiation markers, such as ALP, bone sialoprotein and runt-related transcription factor 2, increased in these cells. For the in vivo test, we designed and implanted HA-coated PEEK cylinders into a rabbit ilium model by the press-fit method. The bone-implant contact ratio, trabecular number and trabecular thickness were determined using either three-dimensional microcomputed tomography or general two-dimensional histomorphometric analysis. This report demonstrates that the HA coating on the PEEK implant added with the cold spray method increased biocompatibility in vitro and promoted osteointegration in vivo, which suggests that the HA coating may improve the biofunctionality of various medical devices used in clinical applications. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  1. Performance Evaluation and Modeling of Erosion Resistant Turbine Engine Thermal Barrier Coatings

    Science.gov (United States)

    Miller, Robert A.; Zhu, Dongming; Kuczmarski, Maria

    2008-01-01

    The erosion resistant turbine thermal barrier coating system is critical to the rotorcraft engine performance and durability. The objective of this work was to determine erosion resistance of advanced thermal barrier coating systems under simulated engine erosion and thermal gradient environments, thus validating a new thermal barrier coating turbine blade technology for future rotorcraft applications. A high velocity burner rig based erosion test approach was established and a new series of rare earth oxide- and TiO2/Ta2O5- alloyed, ZrO2-based low conductivity thermal barrier coatings were designed and processed. The low conductivity thermal barrier coating systems demonstrated significant improvements in the erosion resistance. A comprehensive model based on accumulated strain damage low cycle fatigue is formulated for blade erosion life prediction. The work is currently aiming at the simulated engine erosion testing of advanced thermal barrier coated turbine blades to establish and validate the coating life prediction models.

  2. Standard hardness conversion tables for metals relationship among brinell hardness, vickers hardness, rockwell hardness, superficial hardness, knoop hardness, and scleroscope hardness

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2007-01-01

    1.1 Conversion Table 1 presents data in the Rockwell C hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.2 Conversion Table 2 presents data in the Rockwell B hardness range on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, Knoop hardness, and Scleroscope hardness of non-austenitic steels including carbon, alloy, and tool steels in the as-forged, annealed, normalized, and quenched and tempered conditions provided that they are homogeneous. 1.3 Conversion Table 3 presents data on the relationship among Brinell hardness, Vickers hardness, Rockwell hardness, Rockwell superficial hardness, and Knoop hardness of nickel and high-nickel alloys (nickel content o...

  3. A performance evaluation of various coatings, substrate materials, and solar collector systems

    Science.gov (United States)

    Dolan, F. J.

    1976-01-01

    An experimental apparatus was constructed and utilized in conjunction with both a solar simulator and actual sunlight to test and evaluate various solar panel coatings, panel designs, and scaled-down collector subsystems. Data were taken by an automatic digital data acquisition system and reduced and printed by a computer system. The solar collector test setup, data acquisition system, and data reduction and printout systems were considered to have operated very satisfactorily. Test data indicated that there is a practical or useful limit in scaling down beyond which scaled-down testing cannot produce results comparable to results of larger scale tests. Test data are presented as are schematics and pictures of test equipment and test hardware.

  4. Evaluation of silver-coated stainless steel bipolar plates for fuel cell applications

    Science.gov (United States)

    Huang, Ing-Bang

    In this study, computer-aided design and manufacturing (CAD/CAM) technology were applied to develop and produce stainless steel bipolar plates for DMFC (direct methanol fuel cell). Effect of surface modification on the cell performance of DMFC was investigated. Surface modifications of the stainless steel bipolar plates were made by the electroless plating method. A DMFC consisting of silver coated stainless steel as anode and uncoated stainless steel as cathode was assembled and evaluated. The methanol crossover rate (R c) of the proton exchange membrane (PEM) was decreased by about 52.8%, the efficiency (E f) of DMFC increased about 7.1% and amounts of methanol electro-oxidation at the cathode side (M co) were decreased by about 28.6%, as compared to uncoated anode polar plates. These measurements were determined by the transient current and mathematical analysis.

  5. Investigation on the corrosion behavior of physical vapor deposition coated high speed steel

    Directory of Open Access Journals (Sweden)

    R Ravi Raja Malarvannan

    2015-08-01

    Full Text Available This work emphasizes on the influence of the TiN and AlCrN coatings fabricated on high speed steel form tool using physical vapor deposition technique. The surface microstructure of the coatings was studied using scanning electron microscope. Hardness and corrosion studies were also performed using Vickers hardness test and salt spray testing, respectively. The salt spray test results suggested that the bilayer coated (TiN- bottom layer and AlCrN- top layer substrate has undergone less amount of corrosion, and this is attributed to the dense microstructure. In addition to the above, the influence of the above coatings on the machining performance of the high speed steel was also evaluated and compared with that of the uncoated material and the results suggested that the bilayered coating has undergone very low weight loss when compared with that of the uncoated substrate depicting enhanced wear resistance.

  6. Polyester based hybrid organic coatings

    Science.gov (United States)

    Wang, Xiaojiang

    terminated polyester were characterized by Brookfield viscometer, NMR and Fourier Transform Infrared spectroscopy (FTIR). UV-curable non-isocyanate polyurethane coatings were formulated by using Acrylated Polyester (APE) oligomer and Non-isocyanate Urethane Dimethacrylates (NUDMA) reactive diluents. The effect of the NUDMA on the viscosity of the APE oligomer was investigated by Brookfield viscometer. The photopolymerization kinetics of NUDMA reactive diluents were investigated by the real time FTIR. It was found that the polymerization conversion and maximum polymerization rate increase with increasing initiator concentration in the range from 0.5 % to 4.0 %. The formulation system containing both the APE oligomer and NUDMA reactive dilutes showed higher polymerization overall conversion and maximum polymerization rate than APE oligomer. After UV curing, the viscoelastic, tensile and thermal properties of the cured films were evaluated as a function of the reactive diluent by using DMTA, tensile test, Differential Scanning Calorimeters (DSC), and Thermal Gravimetric Analysis (TGA). In addition, coating properties such as pencil hardness, chemical resistance, impact resistance, and gloss were also investigated. It was found that crosslink density, storage and tensile modulus, pencil hardness, chemical resistance, gel content, total water absorption, and Tg were directly proportional to amount of the reactive diluents. Compared to the commercial Ethylene Glycol Dimethacrylate (EGDMA) reactive diluent, the NUDMA reactive diluents show significant improvements in impact resistance and elongation at break properties.

  7. Microstructure and cytotoxicity evaluation of duplex-treated silver-containing antibacterial TiO{sub 2} coatings

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiangyu; Wu, Haibo; Geng, Zhenhua; Huang, Xiaobo; Hang, Ruiqiang; Ma, Yong; Yao, Xiaohong; Tang, Bin, E-mail: tangbin6405@sina.com

    2014-12-01

    Implant-related infection is one of the most common and serious complications associated with biomedical implantation. To prevent bacterial adhesion, a series of porous TiO{sub 2} coatings with different concentrations of silver (designated as M0, M1, M2 and M3) were prepared on pure titanium substrates by a duplex-treatment technique combining magnetron sputtering with micro-arc oxidation. All coatings are porous with pore size less than 5 μm and the concentrations of silver in the M0, M1, M2 and M3 are 0, 0.95, 1.36 and 1.93 wt.%, respectively. Silver is found to be distributed throughout the thickness of the coatings by scanning electron microscopy. The release of silver from the TiO{sub 2} coatings was confirmed by an inductively-coupled plasma mass spectroscopy. The antibacterial effects of these coatings were tested against Gram-positive Staphylococcus aureus (S. aureus) and Gram-negative Escherichia coli (E. coli), and the cytotoxicity was evaluated using the mouse pre-osteoblast cells. The results indicate that the antibacterial activities of TiO{sub 2} coatings are greatly improved due to the incorporation of silver. No cytotoxic effect is found for the M1 surfaces from the observation of pre-osteoblast cell by MTT assay and fluorescence microscopy. Although the M2 and M3 coatings appeared to be toxic for pre-osteoblast cells after 1 day in culture, the cell viability on M2 and M3 surfaces was greatly raised after culturing for 2 days. Our results suggested that the TiO{sub 2} coatings incorporated with an optimum amount of silver can possess excellent antibacterial activities without cytotoxic effect, which has promising applications in biomedical devices. - Highlights: • Porous TiO{sub 2} coatings with various concentration of Ag on titanium were prepared. • Ag element was distributed throughout the thickness of the coatings. • The antibacterial activities were greatly improved due to the incorporation of Ag. • The release amounts of Ag were

  8. Hardness analysis and morphological characterization of copper-zinc alloys produced in pyrophosphate-based electrolytes

    Directory of Open Access Journals (Sweden)

    Lilian Ferreira de Senna

    2005-09-01

    Full Text Available In this work, copper-zinc alloy coatings on mild steel substrates were obtained in nontoxic pyrophosphate-based electrolytes, at room temperature and under continuous current. The effects of bath composition and current density on the hardness of the coatings, as well as on their morphologies, were evaluated. The results showed that the electrolyte composition, and the use of stress relieving additives strongly influence the hardness of the coatings, while the current density directly affect their morphology. Hence, for a current density of 116 A/m², copper-zinc alloy deposits with no pores or cracks were produced in a pyrophosphate-based electrolyte, especially when allyl alcohol was added to the solution.

  9. Evaluation of Norfolk Harbor Deepening Project (A Study on Its Possible Impact on Oysters, Hard Clams and Oyster Drills).

    Science.gov (United States)

    1984-06-20

    Virginia 23062 DTIC 20 June 1984 ELECTE ~L&JMAR 12 i9BB IA B! ,", Contract No. DACW65-84-M-0056 -Ap’oved to: publicO t01b0 I D)WtbuZidon Unlimited .~Norfolk...impact on the transport of the larval oysters and hard clams during their planktonic stage. Oysters and hard clams are widely tolerant to high salinity...planktonic for about 2 weeks and during this period are transported by currents. This latter aspect will be covered later in our discussion on oysters. ~i

  10. Evaluation of Iron and Manganese-Coated Pumice Application for the Removal of as(v from Aqueous Solutions

    Directory of Open Access Journals (Sweden)

    Leila Babaie Far

    2012-12-01

    Full Text Available Arsenic contamination of water has been recognized as a serious environmental issue and there are reports on its epidemiological problems to human health. The objective of this study was to evaluate the performances of iron-coated pumice and manganese-coated pumice as the adsorbents for removing arsenate from aqueous solutions. The effect of various parameters such as adsorbent dose, contact time, pH and initial concentration on removal efficiency of arsenate were evaluated in batch mode. The data obtained from the kinetic studies were analyzed using kinetic models of pseudo-first-order and pseudo-second-order. In addition, two isotherm models of Freundlich and Langmuir were used to fit the experimental data. The results showed that the optimum dosage of iron-coated pumice and manganese-coated pumice for arsenate removal were 40 and 80 g/L whereas the adsorption process reached equilibrium after 80 and 100 min, respectively. The maximum removal efficiency of arsenate using the two adsorbents were both recorded in pH=3 as the removal efficiency gradually declinedfollowing every increase in pH values of the solution. Iron-coated pumice also showed to have high removal efficiency when the initial concentration of arsenate was high while the low concentration of arsenate was efficiently removed by manganese-coated pumice. Moreover, it was depicted that the adsorption kinetics by bothadsorbents followed pseudo-second order equation and the uptake data of arsenate were well fitted with Langmuir isotherm model. Therefore, it could be concluded that iron and manganese-coated pumice could beconsidered as suitable adsorbents for arsenate removal from aqueous solutions.

  11. A new non-contact approach for the measurement and uniformity evaluation of coating thickness for sheet metal.

    Science.gov (United States)

    Qiu, Zixue; Zheng, Tianchi; Wan, Liping; Lu, Guan; Shao, Jianxin; Yuan, Jiang

    2017-01-01

    To realize the automatic measurement and uniformity evaluation of the coating thickness for sheet metal, a new non-contact detection method for coating thickness was proposed based on a double laser probe and mechanical servo system. Non-contact measurement of coating thickness can be achieved by differential measurement principle of double laser probe, and the influences of sheet metal's Z position changes and platform's vibration on the measurement results can be removed by this method. A new coating thickness evaluation algorithm by integrating the least squares principle and cubic spline interpolation was given, which can fit the discrete thickness data into visual and accurate 3D graphics; and the measurement accuracy was evaluated based on grey theory, solving the problem of low accuracy by using limited measurement data to evaluate the thickness uniformity of an entire sheet metal. The stability and reliability of the system are verified by experiments, and the measurement results of the specimen show that the measurement uncertainty is 0.016 μm and the maximum range of the uniformity evaluation result is 1.4 μm.

  12. Surface hardness evaluation of different composite resin materials: influence of sports and energy drinks immersion after a short-term period

    Science.gov (United States)

    ERDEMİR, Ugur; YİLDİZ, Esra; EREN, Meltem Mert; OZEL, Sevda

    2013-01-01

    Objectives: This study evaluated the effect of sports and energy drinks on the surface hardness of different composite resin restorative materials over a 1-month period. Material and Methods: A total of 168 specimens: Compoglass F, Filtek Z250, Filtek Supreme, and Premise were prepared using a customized cylindrical metal mould and they were divided into six groups (N=42; n=7 per group). For the control groups, the specimens were stored in distilled water for 24 hours at 37º C and the water was renewed daily. For the experimental groups, the specimens were immersed in 5 mL of one of the following test solutions: Powerade, Gatorade, X-IR, Burn, and Red Bull, for two minutes daily for up to a 1-month test period and all the solutions were refreshed daily. Surface hardness was measured using a Vickers hardness measuring instrument at baseline, after 1-week and 1-month. Data were statistically analyzed using Multivariate repeated measure ANOVA and Bonferroni's multiple comparison tests (α=0.05). Results: Multivariate repeated measures ANOVA revealed that there were statistically significant differences in the hardness of the restorative materials in different immersion times (phardness values of the restorative materials was tested using Bonferroni's multiple comparison tests, and it was observed that specimens stored in distilled water demonstrated statistically significant lower mean surface hardness reductions when compared to the specimens immersed in sports and energy drinks after a 1-month evaluation period (phardness of a restorative material depends on the duration of exposure time, and the composition of the material. PMID:23739850

  13. Friction surfaced Stellite6 coatings

    Energy Technology Data Exchange (ETDEWEB)

    Rao, K. Prasad; Damodaram, R. [Department of Metallurgical and Materials Engineering - Indian Institute of Technology Madras, Chennai 600 036 (India); Rafi, H. Khalid, E-mail: khalidrafi@gmail.com [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Ram, G.D. Janaki [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600 036 (India); Reddy, G. Madhusudhan [Metal Joining Group, Defence Metallurgical Research Laboratory (DMRL) Kanchanbagh, Hyderabad 500 058 (India); Nagalakshmi, R. [Welding Research Institute, Bharat Heavy Electricals Limited, Tiruchirappalli 620 014 (India)

    2012-08-15

    Solid state Stellite6 coatings were deposited on steel substrate by friction surfacing and compared with Stellite6 cast rod and coatings deposited by gas tungsten arc and plasma transferred arc welding processes. Friction surfaced coatings exhibited finer and uniformly distributed carbides and were characterized by the absence of solidification structure and compositional homogeneity compared to cast rod, gas tungsten arc and plasma transferred coatings. Friction surfaced coating showed relatively higher hardness. X-ray diffraction of samples showed only face centered cubic Co peaks while cold worked coating showed hexagonally close packed Co also. - Highlights: Black-Right-Pointing-Pointer Stellite6 used as coating material for friction surfacing. Black-Right-Pointing-Pointer Friction surfaced (FS) coatings compared with casting, GTA and PTA processes. Black-Right-Pointing-Pointer Finer and uniformly distributed carbides in friction surfaced coatings. Black-Right-Pointing-Pointer Absence of melting results compositional homogeneity in FS Stellite6 coatings.

  14. Silver-doped nanocomposite carbon coatings (Ag-DLC) for biomedical applications – Physiochemical and biological evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Bociaga, Dorota, E-mail: dorota.bociaga1@gmail.com [Division of Biomedical Engineering and Functional Materials, Lodz University of Technology, Institute of Materials Science and Engineering, 1/15 Stefanowskiego St., 90-924 Lodz (Poland); Komorowski, Piotr [Division of Biophysics, Lodz University of Technology, Institute of Materials Science and Engineering, 1/15 Stefanowskiego St., 90-924 Lodz (Poland); BioNanoPark Laboratories of Lodz Regional Park of Science and Technology, Lodz (Poland); Batory, Damian [Division of Biomedical Engineering and Functional Materials, Lodz University of Technology, Institute of Materials Science and Engineering, 1/15 Stefanowskiego St., 90-924 Lodz (Poland); Szymanski, Witold [Division of Biophysics, Lodz University of Technology, Institute of Materials Science and Engineering, 1/15 Stefanowskiego St., 90-924 Lodz (Poland); Olejnik, Anna; Jastrzebski, Krzysztof [Division of Biomedical Engineering and Functional Materials, Lodz University of Technology, Institute of Materials Science and Engineering, 1/15 Stefanowskiego St., 90-924 Lodz (Poland); Jakubowski, Witold [Division of Biophysics, Lodz University of Technology, Institute of Materials Science and Engineering, 1/15 Stefanowskiego St., 90-924 Lodz (Poland)

    2015-11-15

    Graphical abstract: - Highlights: • The DLC coatings with interlayer improving adhesion were manufactured using the author's method in dual RF/MS PCVD system. • The Ag ions were incorporated into DLC matrix using ion beam implantation method. • The morphology, chemical structure and composition of coatings were examined. • Viability, cytotoxicity of human cells and the formation of bacterial biofilm on the samples surface were evaluated. • <5% of Ag in DLC coating is efficient to make it bactericidal and biocompatible. - Abstract: The formation of bacteria biofilm on the surface of medical products is a major clinical issue nowadays. Highly adaptive ability of bacteria to colonize the surface of biomaterials causes a lot of infections. This study evaluates samples of the AISI 316 LVM with special nanocomposite silver-doped (by means of ion implantation) diamond-like carbon (DLC) coating prepared by hybrid RF/MS PACVD (radio frequency/magnetron sputtering plasma assisted chemical vapour deposition) deposition technique in order to improve the physicochemical and biological properties of biomaterials and add new features such as antibacterial properties. The aim of the following work was to evaluate antimicrobial efficacy and biocompatibility of gradient a-C:H/Ti + Ag coatings in relation to the physiochemical properties of the surface and chemical composition of coating. For this purpose, samples were tested in live/dead test using two cell strains: human endothelial cells (Ea.hy926) and osteoblasts-like cells (Saos-2). For testing bactericidal activity of the coatings, an exponential growth phase of Escherichia coli strain DH5α was used as a model microorganism. Surface condition and its physicochemical properties were investigated using SEM, AFM and XPS. Examined coatings showed a uniformity of silver ions distribution in the amorphous DLC matrix, good biocompatibility in contact with mammalian cells and an increased level of bactericidal

  15. MULTILAYER COATINGS Ti/TiN, Cr/CrN AND W/WN DEPOSITED BY MAGNETRON SPUTTERING FOR IMPROVEMENT OF ADHESION TO BASE MATERIALS

    Directory of Open Access Journals (Sweden)

    Jakub Horník

    2015-12-01

    Full Text Available The paper deals with evaluation of single and multilayer layer PVD coatings based on Cr and Ti widely used in tool application. Additionally, W and WN based coating which are not so widespread were designed and deposited as functionally graded material. The coatings properties were evaluated from the point of view of hardness and adhesion. The hardness measuring was carried out using nanoindentation method. The scratch test was performed to test adhesion. Moreover, the presence of metallic interlayer in functionally graded materials further increases the coating adhesion by gradually approaching its composition to the substrate. Coatings consisting of W and WN have showed very good adhesion. With regard to the results of the scratch test, the multilayer coatings of CrN, TiN and WN have increased adhesion and can be assumed to have their protective function improved. Results will be appliedin development of functionally graded layers for functionally graded materials.

  16. Coatings and Tints of Spectacle Lenses

    Directory of Open Access Journals (Sweden)

    H. Zeki Büyükyıldız

    2012-10-01

    Full Text Available Spectacle lenses are made of mineral or organic (plastic materials. Various coatings and tints are applied to the spectacle lenses according to the characteristic of the lens material, and for the personal needs and cosmetic purpose. The coatings may be classified in seven groups: 1 Anti-reflection coatings, 2 Hard coatings, 3 Clean coat, 4 Mirror coatings, 5 Color tint coating (one of coloring processes, 6 Photochromic coating (one of photochromic processes, and 7 Anti-fog coatings. Anti-reflection coatings reduce unwanted reflections from the lens surfaces and increase light transmission. Hard coatings are applied for preventing the plastic lens surface from scratches and abrasion. Hard coatings are not required for the mineral lenses due to their hardness. Clean coat makes the lens surface smooth and hydrophobic. Thus, it prevents the adherence of dust, tarnish, and dirt particles on the lens surface. Mirror coatings are applied onto the sunglasses for cosmetic purpose. Color tinted and photochromic lenses are used for sun protection and absorption of the harmful UV radiations. Anti-fog coatings make the lens surface hydrophilic and prevent the coalescence of tiny water droplets on the lens surface that reduces light transmission. (Turk J Ophthalmol 2012; 42: 359-69

  17. ELECTRON BEAM CURING OF EPOXY ACRYLATE COATINGS ON MEDIUM-DENSITY FIBERBOARD

    Directory of Open Access Journals (Sweden)

    Sugiarto Danu

    2010-06-01

    Full Text Available Most of the medium-density fiberboard (MDF as an engineered woods need surface coating process before entering final products, such as furniture and building materials. The wood surface should be covered for surface protection from damage during service life as well as to enhance its appearance. Surface coating of MDF was conducted using epoxy acrylate resin either for clear and pigmented coatings. Titanium dioxide was used for white pigmented coatings. Coating was conducted at variation thickness level of 30 to 150 μm. Curing was carried out by using 350 kV electron beam accelerator at 1.35 mA current and 1.6 m/min conveyor speed to get the absorbed dose of 3 Mrad. Effect of coating thickness was evaluated by measuring the physical, mechanical and chemical properties of cured samples, i.e., hardness, gloss, transparency, adhesion, abrasion resistance, and chemical, solvent and stain resistance. Experimental results showed that pendulum hardness and abrasion resistance slightly increased whereas gloss, transparency and adhesion resistance decreased with increasing coating thickness, while chemical, solvent and stain resistance remains similar. In general, clear coating provides better properties than pigmented coating.   Keywords: electron-beam; coating; epoxy-acrylate; pigment; medium-density fiberboard

  18. Evaluating the sensitivity, reproducibility and flexibility of a method to test hard shell capsules intended for use in dry powder inhalers

    OpenAIRE

    Chong, Rosalind H.E.; Jones, Brian E.; Díez, Fernando; Birchall, James C.; Coulman, Sion A

    2016-01-01

    Pharmaceutical tests for hard shell capsules are designed for orally administered capsules. The use of capsules in dry powder inhalers is widespread and increasing and therefore more appropriate tests are required to ensure quality and determine if these capsules are fit for purpose. This study aims to determine the flexibility, reproducibility and sensitivity of a quantitative method that is designed to evaluate the puncture characteristics of different capsule shell formulations under diffe...

  19. Comparative Evaluation of Osseointegration of Dental Endodontic Implants with and without Plasma- Sprayed Hydroxy apatite Coating

    OpenAIRE

    Moosavi SB.; Fathi MH. BS; MSC; Feizi Gh; Mortazavi V

    2001-01-01

    Bone osseointegration around dental implant can cause earlier stabilization and fixation of implant and reduce healing time. Hydroxyapatite coating can affect bone osseointegration and enhance its rates. The aim of this study was comparison of osseointegration between plasma sprayed hydroxyapatite coated and uncoated dental implants in cats. Four endodontic implants including, vitallium and two stainless steel with and without hydroxyapatite coating were prepared and placed in mandibular cani...

  20. Erosion of wind turbine blade coatings - Design and analysis of jet-based laboratory equipment for performance evaluation

    DEFF Research Database (Denmark)

    Zhang, Shizhong; Dam-Johansen, Kim; Nørkjær, Sten

    2015-01-01

    of the blades in such equipment. To reduce expensive blade maintenance repairs and to avoid out-of-service periods, energy-absorbing blade coatings are required to protect rotor blades from rain erosion. In this work we describe the design, construction and evaluation of a laboratory setup for fast screening...

  1. EVALUATION OF THE EFFECTIVENESS OF COATINGS IN REDUCING DISLODGEABLE ARSENIC, CHROMIUM, AND COPPER FROM CCA TREATED WOOD, INTERIM DATA REPORT

    Science.gov (United States)

    EPA is approximately 20 months into a project to evaluate the performance of wood coatings as a way to prevent arsenic, chromium and copper exposure from the surfaces of CCA treated wood. Potential dermal exposure, as measured by wipe sampling dislodgeable CCA chemical from wood ...

  2. First-in-man evaluation of the MOMO cobalt-chromium carbon-coated stent.

    Science.gov (United States)

    Kesavan, Sujatha; Strange, Julian W; Johnson, Thomas W; Flohr-Roese, Silke; Baumbach, Andreas

    2013-01-22

    Bare metal stents continue to be used for the interventional treatment of coronary artery disease. We report the clinical and angiographic results of a multicentre, single-arm evaluation of safety and feasibility of the MOMO stent (Japan Stent Technology Co., Ltd, Okayama Research Park Incubation Centre, Okayama, Japan). The MOMO stent is a novel thin-strut cobalt-chromium carbon-coated stent for the treatment of de novo coronary artery disease (CAD). In this prospective, non-randomised, single-arm study, 40 patients (stable and unstable angina) with single-vessel CAD were recruited into the study from three centres. Patients with lesions ≤15 mm in length and with a target vessel diameter of ≥3 mm were eligible. Angiographic follow-up was performed at six months. Quantitative coronary angiography (QCA) was used to measure acute gain and late luminal loss (LLL). Intravascular ultrasound (IVUS) was performed in 15 consecutive patients from two centres to assess the degree of neointimal proliferation within the stented segment at six-month follow-up. The MOMO stent performed well without any procedural complications with an acute procedure and technical success rate of 100%. Repeat revascularisation was performed in six patients (15%) during the six-month follow-up. Ischaemia-driven revascularisation was documented in three patients (7.5%). No myocardial infarction, stent thrombosis or cardiac death was observed. One non-cardiac death was reported secondary to lung cancer. Binary restenosis was 12.5% (n=5), and the LLL was 0.54±0.3 mm. This first-in-man experience demonstrates proof of concept of the safety and feasibility of the MOMO cobalt-chromium carbon-coated stent for patients with single focal de novo lesions presenting with stable and unstable CAD.

  3. The evaluation of arterial stiffness of essential hypertension and white coat hypertension in children: a case-control study.

    Science.gov (United States)

    Terlemez Tokgöz, Semiha; Yılmaz, Dilek; Tokgöz, Yavuz; Çelik, Bülent; Bulut, Yasin

    2017-12-10

    The aim of this study was to determine and compare cardiovascular risks by assessing arterial stiffness in children with essential hypertension and white coat hypertension. Paediatric patients followed up with essential hypertension and white coat hypertension diagnoses and with no established end organ damage were involved in the study. Arterial stiffness in children included in the study was evaluated and compared by using the oscillometric device (Mobil-O-Graph) method. A total of 62 essential hypertension (34 male, 28 female), 38 white coat hypertension (21 male, 17 female), and 60 healthy controls (33 male, 27 female) were assessed in the present study. Pulse wave velocity of the essential hypertension, white coat hypertension, and control group was, respectively, as follows: 5.3±0.6 (m/s), 5.1±0.4 (m/s), 4.3±0.4 (m/s) (p<0.001); augmentation index outcomes were, respectively, determined as follows: 21.3±6.5, 19.3±6.4, 16.0±0.3 (p<0.001). Pulse wave velocity and augmentation index values of children with essential hypertension and white coat hypertension were found to be higher compared with the control group. This level was identified as correlated with the duration of hypertension in both patient groups (p<0.01). Arterial stiffness in children with essential hypertension and white coat hypertension was impaired compared with healthy children. This finding has made us think that white coat hypertension is not an innocent clinical situation. This information should be taken into consideration in the follow-up and treatment approaches of the patients.

  4. Formulation development of carvedilol compression coated tablet.

    Science.gov (United States)

    Shah, Ritesh; Patel, Sachin; Patel, Hetal; Pandey, Sonia; Shah, Shailesh; Shah, Dinesh

    2013-01-01

    The aim of present research was to produce carvedilol compression coated tablet to provide biphasic drug release. A compressed coated tablet made of a sustained release core tablet and an immediate release coat tablet. Both the core and the coat contained carvedilol. The sustained release effect was achieved with polymers (HPMC K4M and PEO WSR 205) to modulate the release of the drug. The powder blends for core and coat tablets were evaluated for angle of repose, bulk density, compressibility index, and drug content. Compressed coated tablets were evaluated for thickness, diameter, weight variation test, drug content, hardness, friability, disintegration and in vitro release studies. The powder blends showed satisfactory flow properties, compressibility, drug content and all the tablet formulations showed acceptable pharmaco-technical properties. Carvedilol contained in the fast releasing component was released within 3 min, whereas the drug in the core tablet was released at different times up to 24 h, depending on the composition of the matrix tablet. The mechanism of drug release was fickian diffusion or anomalous behavior. Batch F7, containing 10 mg PEO WSR 205 and 5 mg HPMC K4M, showed maximum similarity with theoretical profile and zero order drug release kinetic.

  5. Influence of Plasma Transferred Arc Process Parameters on Structure and Mechanical Properties of Wear Resistive NiCrBSi-WC/Co Coatings

    Directory of Open Access Journals (Sweden)

    Eitvydas GRUZDYS

    2011-07-01

    Full Text Available Self-fluxing NiCrBSi and related coatings received considerable interest due to their good wear as well as corrosion resistance at moderate and elevated temperatures. Hard tungsten carbide (WC particles can be included in NiCrBSi for further increase of the coating hardness and abrasive wear resistance. Flame spray technique is widely used for fabrication of NiCrBSi films. However, in such a case, subsequent remelting of the deposited coatings by flame, arc discharge or high power laser beam is necessary. In present study NiCrBSi-WC/Co coatings were formed using plasma transferred arc process. By adjusting plasma parameters, such as current, plasma gas flow, shielding gas flow, a number of coatings were formed on steel substrates. Structure of the coatings was investigated using X-ray diffractometry. Microstructure of cross-sectioned coatings was examined using scanning electron microscopy. Hardness of the coating was evaluated by means of the Vickers hardness tests. Wear tests were also performed on specimens to determine resistance to abrasive wear. Acquired results allowed estimating the influence of the deposition process parameters on structure and mechanical properties of the coatings.http://dx.doi.org/10.5755/j01.ms.17.2.482

  6. Study of Different Sol-Gel Coatings to Enhance the Lifetime of PDMS Devices: Evaluation of Their Biocompatibility

    Directory of Open Access Journals (Sweden)

    María Aymerich

    2016-08-01

    Full Text Available A study of PDMS (polydimethylsiloxane sol-gel–coated channels fabricated using soft lithography and a laser direct writing technique is presented. PDMS is a biocompatible material that presents a high versatility to reproduce several structures. It is widely employed in the fabrication of preclinical devices due to its advantages but it presents a rapid chemical deterioration to organic solvents. The use of sol-gel layers to cover the PDMS overcomes this problem since it provides the robustness of glass for the structures made with PDMS, decreasing its deterioration and changing the biocompatibility of the surface. In this work, PDMS channels are coated with three different kinds of sol-gel compositions (60MTES/40TEOS, 70MTES/30TISP and 80MTES/20TISP. The endothelial cell adhesion to the different coated devices is evaluated in order to determine the most suitable sol-gel preparation conditions to enhance cellular adhesion.

  7. Evaluation of Different Single-Walled Carbon Nanotube Surface Coatings for Single-Particle Tracking Applications in Biological Environments.

    Science.gov (United States)

    Gao, Zhenghong; Danné, Noémie; Godin, Antoine Guillaume; Lounis, Brahim; Cognet, Laurent

    2017-11-16

    Fluorescence imaging of biological systems down to the single-molecule level has generated many advances in cellular biology. For applications within intact tissue, single-walled carbon nanotubes (SWCNTs) are emerging as distinctive single-molecule nanoprobes, due to their near-infrared photoluminescence properties. For this, SWCNT surfaces must be coated using adequate molecular moieties. Yet, the choice of the suspension agent is critical since it influences both the chemical and emission properties of the SWCNTs within their environment. Here, we compare the most commonly used surface coatings for encapsulating photoluminescent SWCNTs in the context of bio-imaging applications. To be applied as single-molecule nanoprobes, encapsulated nanotubes should display low cytotoxicity, and minimal unspecific interactions with cells while still being highly luminescent so as to be imaged and tracked down to the single nanotube level for long periods of time. We tested the cell proliferation and cellular viability of each surface coating and evaluated the impact of the biocompatible surface coatings on nanotube photoluminescence brightness. Our study establishes that phospholipid-polyethylene glycol-coated carbon nanotube is the best current choice for single nanotube tracking experiments in live biological samples.

  8. A Field Performance Evaluation Scheme for Microwave-Absorbing Material Coatings

    Directory of Open Access Journals (Sweden)

    Shaopeng Guan

    2017-03-01

    Full Text Available Performance evaluation is an important aspect in the study of microwave-absorbing material coatings. The reflectivity of the incident wave is usually taken as the performance indicator. There have been various methods to directly or indirectly measure the reflectivity, but existing methods are mostly cumbersome and require a strict testing environment. What is more, they cannot be applied to field measurement. In this paper, we propose a scheme to achieve field performance evaluation of microwave-absorbing materials, which adopts a small H-plane sectoral horn antenna as the testing probe and a small microwave reflectometer as the indicator. When the size of the H-plane sectoral horn antenna is specially designed, the field distribution at the antenna aperture can be approximated as a plane wave similar to the far field of the microwave emitted by a radar unit. Therefore, the reflectivity can be obtained by a near-field measurement. We conducted experiments on a kind of ferrite-based microwave-absorbing material at X band (8.2–12.4 GHz to validate the scheme. The experimental results show that the reflectivity is in agreement with the reference data measured by the conventional method as a whole.

  9. Evaluation of Perovskite Overlay Coatings on Ferritic Stainless Steels for SOFC Interconnect Applications

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Z Gary; Xia, Gordon; Maupin, Gary D.; Stevenson, Jeffry W.

    2006-08-02

    Conductive oxide coatings are used to improve electrical performance and surface stability of metallic interconnects, as well as to mitigate or prevent chromium poisoning in solid oxide fuel cells (SOFCs). To further understand materials suitability and shed light on mass transport, two conductive perovskites, were taken as examples and applied as dense coatings via radio frequency (rf)-sputtering on three stainless steels.

  10. EXPERIMENTAL STUDY FOR PERFORMANCE EVALUATION OF INSULATOR USING VARIOUS COATING MATERIALS UNDER DIFFERENT ATMOSPHERIC CONDITIONS

    OpenAIRE

    Akshay Singh Thakur; Prof. Arun Pachori

    2017-01-01

    In this study, we have an insulator is subjected to high voltage under various atmospheric condition. Without porcelain and asbestos coatings to judge the performance and with porcelain and asbestos coatings to judge the performance of electrical insulation materials, upto 44 KV during various atmospheric condition. And for porcelain insulating material, upto 41 KV.

  11. Evaluation of thermal control coatings for use on solar dynamic radiators in low earth orbit

    Science.gov (United States)

    Dever, Joyce A.; Rodriguez, Elvin; Slemp, Wayne S.; Stoyack, Joseph E.

    1991-01-01

    Thermal control coatings with high thermal emittance and low solar absorptance are needed for Space Station Freedom (SSF) solar dynamic power module radiator (SDR) surfaces for efficient heat rejection. Additionally, these coatings must be durable to low earth orbital (LEO) environmental effects of atomic oxygen, ultraviolet radiation and deep thermal cycles which occur as a result of start-up and shut-down of the solar dynamic power system. Eleven candidate coatings were characterized for their solar absorptance and emittance before and after exposure to ultraviolet (UV) radiation (200 to 400 nm), vacuum UV (VUV) radiation (100 to 200 nm) and atomic oxygen. Results indicated that the most durable and best performing coatings were white paint thermal control coatings Z-93, zinc oxide pigment in potassium silicate binder, and YB-71, zinc orthotitanate pigment in potassium silicate binder. Optical micrographs of these materials exposed to the individual environmental effects of atomic oxygen and vacuum thermal cycling showed that no surface cracking occurred.

  12. Evaluation of coating adhesion using a radial speckle interferometer combined with a micro-indentation test

    Science.gov (United States)

    Tendela, Lucas P.; Kaufmann, Guillermo H.

    2012-06-01

    This paper presents a technique to investigate coating adhesion which combines a radial in-plane speckle interferometer and a micro-indentation test. The proposed technique is based on the measurement of the radial in-plane displacement field produced by a micro-indentation introduced on the coated surface of the specimen. Using steel specimens coated with a thin coating of epoxy paint and subjected to different adhesive conditions, it is demonstrated that digital speckle pattern interferometry can be successfully used to measure the small local deformations generated by a micro-indentation. An empirical model, which allows to quantify the adhesion of a given coated-substrate system by the proposed combined technique, is finally presented.

  13. Comparative Evaluation of Osseointegration of Dental Endodontic Implants with and without Plasma- Sprayed Hydroxy apatite Coating

    Directory of Open Access Journals (Sweden)

    Moosavi SB

    2001-05-01

    Full Text Available Bone osseointegration around dental implant can cause earlier stabilization and fixation of implant and reduce healing time. Hydroxyapatite coating can affect bone osseointegration and enhance its rates. The aim of this study was comparison of osseointegration between plasma sprayed hydroxyapatite coated and uncoated dental implants in cats. Four endodontic implants including, vitallium and two stainless steel with and without hydroxyapatite coating were prepared and placed in mandibular canines of 20 cats after completion of root canal treatment and osseous preparation. After a healing period of 4 months, investigation by scanning electron microscopy showed significant difference in ossointegration between coated and uncoated dental implants and average bone osseointegration of coated implants was more than uncoated implants.

  14. SEM evaluation of the morphological changes in hard dental tissues prepared by Er: YAG laser and rotary instruments

    Directory of Open Access Journals (Sweden)

    Tomov Georgi

    2010-09-01

    Full Text Available Effective ablation of dental hard tissues by means of the erbium:yttrium-aluminum garnet (Er: YAG laser has been reported recently, and its application to caries removal and cavity preparation has been expected. However, few studies have investigated the morphological changes in hard dental tissues after Er: YAG laser caries treatment. In the present study the morphological changes in hard dental tissues after Er: YAG laser caries ablation in vitro was compared with that of conventional mechanical treatment. Thirty extracted human teeth with caries were used. Ten tooth was treated with the Er: YAG laser, and the other was treated with a conventional steel and diamond burs. Laser treatment was performed by means of a non-contact irradiation modes with cooling water spray, with a new Er: YAG laser (LiteTouch. Conventional bur treatment was conducted by means of a low-speed micromotor and air turbine with water cooling. Scanning electron microscope (SEM observations were performed for each treatment. The Er: YAG laser ablated carious dentin effectively with minimal thermal damage to the surrounding intact dentin, and removed infected and softened carious dentin to the same degree as the burtreatment. In addition, a lower degree of vibration was noted with the Er: YAG laser treatment. The SEM examination revealed characteristic micro-irregularities of the lased dentin and enamel surfaces with potential benefits for adhesive restorations. Our results show that the Er: YAG laser is promising as a new technical modality for caries treatment

  15. Effect of substrate hardness and film structure on indentation depth criteria for film hardness testing

    Energy Technology Data Exchange (ETDEWEB)

    Manika, Ilze; Maniks, Janis [Institute of Solid State Physics, University of Latvia, 8 Kengaraga Str., Riga LV1063 (Latvia)], E-mail: manik@latnet.lv

    2008-04-07

    The indentation depth limits for the Vickers microhardness testing of amorphous, polycrystalline, multilayer and single crystal coatings were investigated. The coating/substrate hardness ratio was varied in the range from 0.01 to 20. The critical indentation depth h{sub c}, below which the substrate has a negligible effect on the hardness, was estimated from the experimentally obtained hardness versus indentation depth curves. The results show a marked effect of the coating structure on the size of the influence zone beneath the indenter. The indentation depth limits were found to increase in the row of single crystal {yields} polycrystalline {yields} amorphous coatings. The obtained indentation depth criteria are compared with the reference data obtained by using finite element and kinematic calculations.

  16. Phase stability and biological property evaluation of plasma sprayed hydroxyapatite coatings for orthopedic and dental applications.

    Science.gov (United States)

    Vahabzadeh, Sahar; Roy, Mangal; Bandyopadhyay, Amit; Bose, Susmita

    2015-04-01

    In this work we have investigated the effects of strontium (Sr) dopant on in vitro protein release kinetics and in vivo osteogenic properties of plasma sprayed hydroxyapatite (HA) coatings, along with their dissolution behavior. Plasma sprayed HA coatings are widely used in load-bearing implants. Apart from osseointegration, the new generation of HA coating is expected to deliver biomolecules and/or drugs that can induce osteoinduction. This paper reports the preparation of crystalline and amorphous HA coatings on commercially pure titanium (Cp-Ti) using inductively coupled radio frequency (RF) plasma spray, and their stability at different solution pH. Coatings prepared at 110 mm working distance from the nozzle showed an average Ca ion release of 18 and 90 ppm in neutral and acidic environments, respectively. Decreasing the working distance to 90 mm resulted in the formation of a coating with less crystalline HA and phases with higher solubility products, and consequently higher dissolution over 32 days. A 92% release of a model protein bovine serum albumin (BSA) in phosphate buffer with pH of 7.4 was measured for Sr-doped HA (Sr-HA) coating, while only a 72% release could be measured for pure HA coating. Distortion of BSA during adsorption on coatings revealed a strong interaction between the protein and the coating, with an increase in α-helix content. Osteoid formation was found on Sr-HA implants as early as 7 weeks post implantation compared to HA coated and uncoated Ti implants. After 12 weeks post implantation, osteoid new bone was formed on HA implants; whereas, bone mineralization started on Sr-HA samples. While no osteoid was formed on bare Ti surfaces, bone was completely mineralized on HA and Sr-HA coatings after 16 weeks post implantation. Our results show that both phase stability and chemistry can have a significant influence toward in vitro and in vivo response of HA coatings on Ti implants. Copyright © 2015 Acta Materialia Inc. Published by

  17. Poly(acrylic acid)-coated iron oxide nanoparticles: quantitative evaluation of the coating properties and applications for the removal of a pollutant dye.

    Science.gov (United States)

    Fresnais, J; Yan, M; Courtois, J; Bostelmann, T; Bée, A; Berret, J-F

    2013-04-01

    In this work, 6-12 nm iron oxide nanoparticles were synthesized and coated with poly(acrylic acid) chains of molecular weight 2100 g mol(-1). Based on a quantitative evaluation of the dispersions, the bare and coated particles were thoroughly characterized. The number densities of polymers adsorbed at the particle surface and of available chargeable groups were found to be 1.9±0.3 nm(-2) and 26±4 nm(-2), respectively. Occurring via a multi-site binding mechanism, the electrostatic coupling leads to a solid and resilient anchoring of the chains. To assess the efficacy of the particles for pollutant remediation, the adsorption isotherm of methylene blue molecules, a model of pollutant, was determined. The excellent agreement between the predicted and the measured amounts of adsorbed dyes suggests that most carboxylates participate to the complexation and adsorption mechanisms. An adsorption of 830 mg g(-1) was obtained. This quantity compares well with the highest values available for this dye. Copyright © 2012 Elsevier Inc. All rights reserved.

  18. Erosion behaviour of WC–10Co–4Cr coating on 23-8-N nitronic steel by HVOF thermal spraying

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Avnish, E-mail: avnishmnit@gmail.com [Department of Metallurgical and Materials Engineering, Malaviya National Institute of Technology, Jaipur, Rajasthan 302017 (India); Sharma, Ashok, E-mail: ashok.mnit12@gmail.com [Department of Metallurgical and Materials Engineering, Malaviya National Institute of Technology, Jaipur, Rajasthan 302017 (India); Goel, S.K., E-mail: skgoel@splsteel.com [Star Wire India Ltd., Ballabgarh, Haryana 121404 (India)

    2016-05-01

    Highlights: • WC–10Co–4Cr powder was HVOF sprayed on cast and solution treated 23-8-N nitronic steel. • Coated solution treated 23-8-N steel shows homogeneous microstructure, less decarburization and high fracture toughness as compared to coated cast steel. • Erosion behaviour of both coated steels was evaluated at two different impact angles. • Coated solution treated 23-8-N nitronic steel exhibits higher erosion resistance as compared to coated cast steel. • Key erosion resistance factors: homogeneous and well-bonded structure, high fracture toughness, optimum substrate properties. - Abstract: WC–10Co–4Cr coating was deposited by high-velocity oxy-fuel (HVOF) process on cast and solution treated (1220 °C/150 min) 23-8-N nitronic steel substrates. Solution treated substrate has shown higher toughness, ductility and impact energy with a marginal reduction in hardness as compared to cast substrate. This influence the coating deposition efficiency and erosion behaviour. Erosion resistance of coatings was evaluated by air jet erosion tester on two different impact angles (30° and 90°). Phases, microstructure and eroded surface of the coating were characterised by X-ray diffraction (XRD) analysis and field-emission scanning electron microscopy (FESEM) respectively. It is observed that coating on solution treated substrate was superior to cast substrate. The reason being that coating has dense and well-bonded structure with low porosity, less decarburization and inter-splat oxidation. Higher erosion resistance of coated solution treated 23-8-N nitronic steel was attributed to combination of high fracture toughness and hardness of coating including optimum mechanical properties of the substrate. FESEM analysis reveals that erosion response of WC–10Co–4Cr coating also dependent on the relative size of the impact crater with respect to the WC grain size. Coating is removed by combined mode of ductile and brittle erosion.

  19. Evaluation and Characterization of Plasma Sprayed Cu Slag-Al Composite Coatings on Metal Substrates

    Directory of Open Access Journals (Sweden)

    S. Mantry

    2013-01-01

    Full Text Available Copper slag is a waste product obtained during matte smelting and refining of copper. The present work explores the coating potential of copper slag by plasma spraying. This work shows that copper slag is eminently coatable. An attempt has been made in the present investigation to use the composites coatings of copper slag and Al powder in suitable combination on aluminium and mild steel substrates in order to improve the surface properties of these ductile metal-alloy substrates. When premixed with Al powder, the coating exhibits higher interfacial adhesion as compared to pure copper slag coatings. Maximum adhesion strengths of about 23 MPa and 21 MPa are recorded for the coatings of copper slag with 15 wt% of Al on aluminium and mild steel substrates, respectively. The input power to the plasma torch is found to affect the coating deposition efficiency and morphology of the coatings. It also suggests value addition of an industrial waste.

  20. Development and stability evaluation of enteric coated Diclofenac sodium tablets using Sureteric.

    Science.gov (United States)

    Zaid, Abdel Naser

    2012-01-01

    This study was aimed to develop a stable enteric coated diclofenac sodium tablets using Sureteic without a subcoating layer. Diclofenac uncoated tablets were developed and manufactured through the non direct compression process. Sureteric white aqueous coating dispersion was used as enteric coating material. Sureteric is a special mixture of Polyvinyl Acetate Phthalate (Phthalavin (R), PVAP), plasticizers and other ingredients in a suitable optimized dry powder formulation. The obtained enteric coated tablets were subjected to disintegration and no sign of cracking was observed when they placed in a hydrochloric solution at pH 1.2, but they were completely disintegrated within 10 minutes when they putted in buffered solution at pH6.8. Dissolution test was also conducted by placing tablets in 0.1 M HCl for 2 hours and then 1 hour in phosphate buffer at pH 6.8. Less than 0.9% of drug was released in the acidic phase and up to 97% in the basic medium. These results show that Sureteric can be successfully used to produce diclofenac sodium enteric coated tablets in order to prevent its release in the stomach and facilitate immediate release of the drug in the duodenum. These findings suggest that aqueous enteric coating with Sureteric system is an easy and economical approach for preparing stable diclofenac sodium enteric coat without the use of a subcoating layer.

  1. Evaluation of extractant-coated ferromagnetic microparticles for the recovery of hazardous metals from waste solution.

    Energy Technology Data Exchange (ETDEWEB)

    Kaminski, M. D.

    1998-05-08

    A magnetically assisted chemical separation (MACS) process was developed earlier at Argonne National Laboratory (ANL). This compact process was designed for the separation of transuranics (TRU) and radionuclides from the liquid waste streams that exist at many DOE sites, with an overall reduction in waste volume requiring disposal. The MACS process combines the selectivity afforded by solvent extractant/ion exchange materials with magnetic separation to provide an efficient chemical separation. Recently, the MACS process has been evaluated with acidic organophosphorus extractants for hazardous metal recovery from waste solutions. Moreover, process scale-up design issues have been addressed with respect to particle filtration and recovery. Two acidic organophosphorus compounds have been investigated for hazardous metal recovery, bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex{reg_sign} 272) and bis(2,4,4-trimethylpentyl) dithiophosphinic acid (Cyanex{reg_sign} 301). Coated onto magnetic microparticles, these extractants demonstrated superior recovery of hazardous metals from solution, relative to what was expected on the basis of results from solvent extraction experiments. The results illustrate the diverse applications of MACS technology for dilute waste streams. Preliminary process scale-up experiments with a high-gradient magnetic separator at Oak Ridge National Laboratory have revealed that very low microparticle loss rates are possible.

  2. Evaluation of bone loss in antibacterial coated dental implants: An experimental study in dogs.

    Science.gov (United States)

    Godoy-Gallardo, Maria; Manzanares-Céspedes, Maria Cristina; Sevilla, Pablo; Nart, José; Manzanares, Norberto; Manero, José M; Gil, Francisco Javier; Boyd, Steven K; Rodríguez, Daniel

    2016-12-01

    The aim of this study was to evaluate the in vivo effect of antibacterial modified dental implants in the first stages of peri-implantitis. Thirty dental implants were inserted in the mandibular premolar sites of 5 beagle dogs. Sites were randomly assigned to Ti (untreated implants, 10units), Ti_Ag (silver electrodeposition treatment, 10units), and Ti_TSP (silanization treatment, 10units). Coated implants were characterized by scanning electron microscopy, interferometry and X-ray photoelectron spectroscopy. Two months after implant insertion, experimental peri-implantitis was initiated by ligature placement. Ligatures were removed 2months later, and plaque formation was allowed for 2 additional months. Clinical and radiographic analyses were performed during the study. Implant-tissue samples were prepared for micro computed tomography, backscattered scanning electron microscopy, histomorphometric and histological analyses and ion release measurements. X-ray, SEM and histology images showed that vertical bone resorption in treated implants was lower than in the control group (Pimplant surface. Histological analysis suggested an increase of peri-implant bone formation on silanized implants. However, the short post-ligature period was not enough to detect differences in clinical parameters among implant groups. Within the limits of this study, antibacterial surface treatments have a positive effect against bone resorption induced by peri-implantitis. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Detailed toxicity evaluation of β-cyclodextrin coated iron oxide nanoparticles for biomedical applications.

    Science.gov (United States)

    Shelat, Ruchita; Chandra, Sudeshna; Khanna, Aparna

    2017-09-20

    The application of iron oxide nanoparticles [IONPs] in biomedical research is progressively increasing, leading to the rapid development of biocompatible and surface modified IONPs. However, there is still a need of information pertaining to its cellular and acute toxicity profile. This work reports the synthesis of β-cyclodextrin coated iron oxide nanoparticles (βCD-IONPs) and their characterization using spectroscopic (FT-IR), thermal (TGA) and surface analysis (TEM, SEM, BET and Zeta potential). All the characterization techniques displayed the synthesis of well dispersed, rod shaped βCD-IONPs of 45nm. Time dependent cellular uptake of these nanoparticles was also evaluated using Prussian blue staining. Further, cytocompatibility analysis was executed in mouse fibroblast cell line (NIH 3T3) using MTT and LDH assays, respectively which did not show any cytotoxic indications of βCD-IONPs. Finally, acute toxicity analysis was carried out in female Wistar rats according to OECD guidelines 420. Rats were exposed to the highest dose (2000mg/kg) of βCD-IONPs along with control and observed for 14days. After two weeks of administration, tissues and blood were collected and subjected to histopathological and biochemical analysis (SGOT, SGPT and ALP). Animals were sacrificed and gross necropsy was carried out. It has been shown that βCD-IONPs does not have any significant toxic effect at the cellular level. Thus, this study provides new perspectives for future biomedical applications. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. The Effect of Bias Voltage and Gas Pressure on the Structure, Adhesion and Wear Behavior of Diamond Like Carbon (DLC Coatings With Si Interlayers

    Directory of Open Access Journals (Sweden)

    Liam Ward

    2014-04-01

    Full Text Available In this study diamond like carbon (DLC coatings with Si interlayers were deposited on 316L stainless steel with varying gas pressure and substrate bias voltage using plasma enhanced chemical vapor deposition (PECVD technology. Coating and interlayer thickness values were determined using X-ray photoelectron spectroscopy (XPS which also revealed the presence of a gradient layer at the coating substrate interface. Coatings were evaluated in terms of the hardness, elastic modulus, wear behavior and adhesion. Deposition rate generally increased with increasing bias voltage and increasing gas pressure. At low working gas pressures, hardness and modulus of elasticity increased with increasing bias voltage. Reduced hardness and modulus of elasticity were observed at higher gas pressures. Increased adhesion was generally observed at lower bias voltages and higher gas pressures. All DLC coatings significantly improved the overall wear resistance of the base material. Lower wear rates were observed for coatings deposited with lower bias voltages. For coatings that showed wear tracks considerably deeper than the coating thickness but without spallation, the wear behavior was largely attributed to deformation of both the coating and substrate with some cracks at the wear track edges. This suggests that coatings deposited under certain conditions can exhibit ultra high flexible properties.

  5. Mechanical Behavior and Sliding Wear Studies on Iron Aluminide Coatings Reinforced with Titanium Carbide

    Directory of Open Access Journals (Sweden)

    Mahdi Amiriyan

    2017-05-01

    Full Text Available Wear-resistant iron aluminide-based composites were coated on steel substrates with the High-Velocity Oxy-Fuel (HVOF technique using ball milled Fe3Al and TiC powders as feedstock. The phase composition, microstructure, microhardness, elastic modulus and dry sliding wear performance of unreinforced Fe3Al and Fe3Al–TiC composite coatings (reinforced with 30 and 50 vol. % TiC particles were evaluated in order to reveal the relationship between the mechanical and tribological behaviors. Compared to the unreinforced coatings, the composite coating with 30 vol. % TiC particles exhibited much greater hardness and higher elastic modulus. The increase of the elastic modulus of the composite coatings did not result in deterioration of sliding wear behavior. The addition of 50 vol. % TiC resulted in a further increase in hardness, however, both composite coatings showed the same elastic modulus. The fractured cross sectional surface of the unreinforced coating showed a weakly bonded microstructure promoting delamination in wear tests, whereas the composite fractured surface showed strong mechanical bonding between the matrix and carbide particles, leading to better cohesion. The Fe3Al–TiC coatings showed almost three orders of magnitude higher wear resistance under the dry sliding wear test compared to the unreinforced coatings.

  6. Evaluation of the effects of water hardness and chemical pollutants on the zooplankton community in uranium mining lakes with acid mine drainage

    Energy Technology Data Exchange (ETDEWEB)

    Nascimento, H.; Ferrari, C.; Nascimento, M.R. [Brazilian Nulcear Energy Commission/Pocos de Caldas Laboratory (Brazil); Rodgher, S. [Universidade Estadual Paulista Julio de Mesquita Filho/Science and Technology Institute (Brazil); Wisniewski, M.J. [Alfenas Federal University/Limnology Laboratory (Brazil)

    2014-07-01

    Several mining lakes are characterized by the inorganic pollution of its waters, known as acid mine drainage (AMD). The current study was developed in order to evaluate the effect of water hardness and chemical pollutants on the richness and density of the zoo-planktonic community species. A seasonal study was conducted in a uranium mining lake affected by AMD. In environmental conditions of extremely high hardness water values (960.3 to 1284,9 mg/l), zoo-planktonic species have indicated resistance to the combined effect of elevated average concentrations of chemical pollutants such as Al (81.9 mg/l), Zn (15.5 mg/l), Mn (102.8 mg/l), U (2.9 mg/l) and low pH values (average = 3.8). Thus, in environments of extreme chemical conditions, such as a uranium mining lake affected by AMD, the hardness showed to be the best predictor of the zoo-planktonic community richness, indicating a protective effect of ions Ca{sup +2} over in special to Bosminopsis deitersi, Bosmina sp., Keratella americana and K. cochlearis. Document available in abstract form only. (authors)

  7. Comparative evaluation of cemental abrasion caused by soft and medium bristle hardness toothbrushes at three predetermined toothbrushing forces: An in vitro study

    Directory of Open Access Journals (Sweden)

    Chaitanya Pradeep Joshi

    2017-01-01

    Full Text Available Background: Plaque control has been shown to have a pivotal role in maintaining optimal periodontal health. Toothbrushing as a mechanical plaque control tool is the most popular and effective option for self-performed oral health maintenance. However, the detrimental effects of bristle hardness and force exerted by toothbrushes on the tooth surface are the areas of concern. Objective: The aim of this in vitro study was to evaluate the abrasive effect of two different manual toothbrushes exerting predetermined forces on cemental surfaces of the teeth. Materials and Methods: Sixty extracted first molars were selected. Totally six experimental groups were formed based on the three predetermined forces 1.5, 3, and 4.5 Newton (N and two types of manual toothbrushes, i.e., soft and medium bristle hardness. Buccal and lingual surfaces were independently brushed for 5000 cycles using specially designed toothbrushing machine. Throughout the experiment, type and quantity of toothpaste were kept constant. Post 5000 cycles of toothbrushing, change in surface roughness was measured using profilometer in microns and change in weight indicating loss of substance was measured in milligrams. Results: Abrasion of cementum is force dependent. Data revealed that both soft and medium bristle hardness toothbrushes cause significant cemental abrasion at 3 and 4.5 N forces. Conclusions: Higher is the force, more is the cemental surface abrasion. Soft bristled toothbrush causes more cemental abrasion than medium bristled toothbrush at 3 and 4.5 N forces.

  8. Evaluating the microstructure and mechanical performance of sputtered TiAlBN nanocomposite coating

    Science.gov (United States)

    Das, Pritam; Anwar, Shahid; Anwar, Sharmistha

    2017-05-01

    We report here the microstructural and mechanical properties of nanocrystalline (nc) Titanium Aluminium Nitride (TiAlN) embedded in nanocrystalline Boron Nitride (BN) nanocomposite films. The coatings were deposited on Si substrate using reactive magnetron co-sputtering by varying BN power. Coatings were characterized by using grazing incident X-ray diffraction (GIXRD), Raman spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray spectroscopy (EDS) and nanoindentation. GIXRD showed the formation of cubic Ti3AlN and hexagonal BN phase in the coating. Variation in structure and target power of BN influence the mechanical property of the coating. Mechanical property increases with power up to 100W, then decrease with further increase in power.

  9. Formulation and evaluation of sustained release enteric-coated pellets of budesonide for intestinal delivery

    National Research Council Canada - National Science Library

    Raval, Mihir K; Ramani, Riddhi V; Sheth, Navin R

    2013-01-01

    ...) full factorial design by giving an enteric coating with Eudragit S100. Budesonide-sustained release pellets were prepared by extruder and spheronization technique using a combination of water-soluble and permeable polymers by applying 3(2...

  10. Evaluation of Hydrogen Cracking in Weld Metal Deposited using Cellulosic-Coated Electrodes

    Science.gov (United States)

    2009-06-16

    Cellulosic-coated electrodes (primarily AWS EXX10-type) are traditionally used for "stovepipe" welding of pipelines because they are well suited for deposition of pipeline girth welds and are capable of high deposition rates when welding downhill. De...

  11. Pharmacokinetic Evaluation of Intranasally Administered Vinyl Polymer-Coated Lorazepam Microparticles in Rabbits

    National Research Council Canada - National Science Library

    Zhao, Yanjun; Brown, Marc B; Khengar, Rajeshree H; Traynor, Matthew J; Barata, Pedro; Jones, Stuart A

    2012-01-01

    .... The aim of this study was to understand how the in situ self-assembly of a mucoretentive delivery system, formed by the dissolution of vinyl polymer-coated microparticles in the nasal mucosa, would...

  12. Comparative Evaluation of Osseointegration of Dental Endodontic Implants with and without Plasma- Sprayed Hydroxy apatite Coating

    National Research Council Canada - National Science Library

    Moosavi SB; Fathi MH. BS; MSC; Feizi Gh; Mortazavi V

    2001-01-01

    ... treatment and osseous preparation. After a healing period of 4 months, investigation by scanning electron microscopy showed significant difference in ossointegration between coated and uncoated dental implants and average bone...

  13. Sol-Gel Coating on Magnesium Alloy and Its Evaluation of Corrosion Resistance

    National Research Council Canada - National Science Library

    Hitonori SATO; Shinji HIRAI; Kazuyoshi SHIMAKAGE; Kenji WADA

    2003-01-01

    .... In comparisons between the composite films prepared by repeating three dip-coatings and an anodic oxide film of magnesium alloy, the acidic corrosion resistances of these films to various acids...

  14. Fly ash based geopolymer thin coatings on metal substrates and its thermal evaluation.

    Science.gov (United States)

    Temuujin, Jadambaa; Minjigmaa, Amgalan; Rickard, William; Lee, Melissa; Williams, Iestyn; van Riessen, Arie

    2010-08-15

    Class F fly ash based Na-geopolymer formulations have been applied as fire resistant coatings on steel. The main variables for the coating formulations were Si: Al molar and water: cement weight ratios. We have determined that the adhesive strength of the coatings strongly depend on geopolymer composition. The ease with which geopolymer can be applied onto metal surfaces and the resultant thickness depend on the water content of the formulation. Adhesive strengths of greater than 3.5 MPa have been achieved on mild steel surfaces for compositions with Si:Al of 3.5. Microstructure evolution and thermal properties of the optimised coating formulations show that they have very promising fire resistant characteristics. Copyright 2010 Elsevier B.V. All rights reserved.

  15. Ex vivo evaluation of four final irrigation protocols on the removal of hard-tissue debris from the mesial root canal system of mandibular first molars.

    Science.gov (United States)

    Leoni, G B; Versiani, M A; Silva-Sousa, Y T; Bruniera, J F B; Pécora, J D; Sousa-Neto, M D

    2017-04-01

    To evaluate the efficacy of four final irrigation protocols on the reduction of hard-tissue debris accumulated within the mesial root canal system of mandibular first molars using micro-CT analysis. Forty mesial roots of mandibular molars with a single and continuous isthmus connecting the mesiobuccal and mesiolingual canals (Vertucci's Type I configuration) were selected and scanned at a resolution of 8.6 μm. Canals were enlarged sequentially using WaveOne Small and Primary instruments activated in reciprocating motion without intracanal irrigation to allow debris to accumulate within the mesial root canal system. Then, specimens were anatomically matched and distributed into four groups (n = 10), according to the final irrigation protocol: apical positive pressure (APP), passive ultrasonic irrigation (PUI), Self-adjusting File (SAF) and XP-endo Finisher (XPF). The final irrigation procedures were performed over 2 min using a total of 5.5 mL of 2.5% NaOCl per canal. Reconstructed data sets were coregistered, and the mean percentage reduction of accumulated hard-tissue debris after the final irrigation procedures was compared statistically between groups using the anovapost hoc Tukey test with a significance level set at 5%. Reduction of accumulated hard-tissue debris was observed in all groups after the final irrigation protocol. Overall, PUI and XPF groups had higher mean percentage reductions of accumulated hard-tissue debris (94.1% and 89.7%, respectively) than APP and SAF groups (45.7% and 41.3%, respectively) (P  0.05) or APP and SAF groups (P > 0.05). The PUI technique and XP-endo Finisher instrument were associated with significantly lower levels of AHTD compared with conventional irrigation and the modified SAF system protocol in mesial root canals of mandibular molars. © 2016 International Endodontic Journal. Published by John Wiley & Sons Ltd.

  16. Synthesis and Evaluation of Poly(3,4-ethylenedioxythiophene) (PEDOT) Coated Magnesium for Nerve Regeneration

    OpenAIRE

    Sebaa, Meriam Amel

    2012-01-01

    In an attempt to develop conductive, biodegradable, mechanically strong, and biocompatible nerve conduits, pure magnesium (Mg) was used as the biodegradable substrate material to provide strength while the conductive polymer, poly(3,4ethylenedioxythiophene) (PEDOT) was used as a conductive coating material to control Mg degradation and improve cytocompatibility of Mg substrates. A series of electrochemical deposition conditions were explored to produce a uniform, consistent PEDOT coating on M...

  17. Characterization and coating stability evaluation of nickel-titanium orthodontic esthetic wires: an in vivo study

    Directory of Open Access Journals (Sweden)

    Nina ARGALJI

    2017-08-01

    Full Text Available Abstract The objective of this study was to compare coating dimensions and surface characteristics of two different esthetic covered nickel-titanium orthodontic rectangular archwires, as-received from the manufacturer and after oral exposure. The study was designed for comparative purposes. Both archwires, as-received from the manufacturer, were observed using a stereomicroscope to measure coating thickness and inner metallic dimensions. The wires were also exposed to oral environment in 11 orthodontic active patients for 21 days. After removing the samples, stereomicroscopy images were captured, coating loss was measured and its percentage was calculated. Three segments of each wire (one as-received and two after oral exposure were observed using scanning electron microscopy for a qualitative analysis of the labial surface of the wires. The Lilliefors test and independent t-test were applied to verify normality of data and statistical differences between wires, respectively. The significance level adopted was 0.05. The results showed that the differences between the wires while comparing inner height and thickness were statistically significant (p < 0.0001. In average, the most recently launched wire presented a coating thickness twice that of the control wire, which was also a statistically significant difference. The coating loss percentage was also statistically different (p = 0.0346 when the latest launched wire (13.27% was compared to the control (29.63%. In conclusion, the coating of the most recent wire was thicker and more uniform, whereas the control had a thinner coating on the edges. After oral exposure, both tested wires presented coating loss, but the most recently launched wire exhibited better results.

  18. Investigation of Characteristics of Sprayed Ni-Cr and Ni-Cr-Wc Coatings

    Directory of Open Access Journals (Sweden)

    Ovidijus Jarašūnas

    2017-01-01

    Full Text Available The article deals with the flame sprayed Ni-Cr and Ni-Cr-WC coatings on construction S235 steel substrates. Before spraying, the surfaces of substrates were treated mechanically. Using the different chemical composition of Ni-Cr and Ni-Cr-WC spraying powder and additional substrate heating till 250–290 °C, were sprayed coatings. The microstructure, porosity, hardness, elastic modulus, wear resistance of the Ni-Cr and Ni-Cr-WC coatings were investigated in the work. The influence of the chemical composition and WC content of the coatings on the various physical and tribological properties of the coatings were evaluated. Also the dependence of these coatings characteristics was investigated.

  19. Development of Ceramic Coating on Metal Substrate using Industrial Waste and Ore Minerals

    Science.gov (United States)

    Bhuyan, S. K.; Thiyagarajan, T. K.; Mishra, S. C.

    2017-02-01

    The technological advancement in modern era has a boon for enlightening human life; but also is a bane to produce a huge amount of (industrial) wastes, which is of great concern for utilization and not to create environmental threats viz. polution etc. In the present piece of research work, attempts have been made to utilize fly ash (wastes of thermal power plants) and along with alumina bearing ore i.e. bauxite, for developing plasma spray ceramic coatings on metals. Fly ash and with 10 and 20% bauxite addition is used to deposit plasma spray coatings on a metal substrate. The surface morphology of the coatings deposited at different power levels of plasma spraying investigated through SEM and EDS analysis. The coating thickness is measured. The porosity levels of the coatings are evaluated. The coating hardness isalso measured. This piece of research work will be beneficial for future development and use of industrial waste and ore minerals for high-valued applications.

  20. Evaluation and Comparison of Aluminum-Coated Pumice and Zeolite in Arsenic Removal From Water Resources

    Directory of Open Access Journals (Sweden)

    Simin Nasseri

    2012-12-01

    Full Text Available In this research the potential of aluminum-coated pumice and zeolite in arsenic, As (V removal was investigated and compared. Scanning Electron Microscopy (SEM, X-Ray Diffraction (XRD and X-Ray Flaorescence Spectrometry (XRF were carried out to determine the properties of the adsorbents. Several parameters including adsorbentdosage] pH, contact time, and initial As(V concentration were studied. The optimum pH obtained for both adsorbents was pH = 7. As(V adsorption by both adsorbents followed the Freundlich isotherm (for aluminum-coated pumice and zeolite respectively with R2 > 0.98 and R2 > 0.99. The obtained data from kinetics showed that the pseudo-second order model could better explain As(V adsorption for both aluminum-coated pumice and zeolite (R2 > 0.98 and R2 > 0.99 respectively. Because of low cost, both adsorbents may beeconomically used, but aluminum-coated zeolite showed high efficiency of, due to its porosity and surface area.More than 96% of As(V with initial concentration of 250 μg/L was removed by 10 g/L aluminum-coated zeolite at pH = 7 and in 60 minutes to achieve As(V concentration of 10 μg/L, while only 71% of As(V could be removed by aluminum-coated pumice.

  1. Corrosion and nanomechanical behaviors of plasma electrolytic oxidation coated AA7020-T6 aluminum alloy

    Energy Technology Data Exchange (ETDEWEB)

    Venugopal, A., E-mail: arjun_venu@hotmail.com [Materials and Metallurgy Group, Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Thiruvananthapuram (India); Srinath, J. [Materials and Metallurgy Group, Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Thiruvananthapuram (India); Rama Krishna, L. [International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), Balapur P.O., Hyderabad 500005 (India); Ramesh Narayanan, P.; Sharma, S.C.; Venkitakrishnan, P.V. [Materials and Metallurgy Group, Materials and Mechanical Entity, Vikram Sarabhai Space Centre, Thiruvananthapuram (India)

    2016-04-13

    Alumina coating was deposited on AA7020 aluminum alloy by plasma electrolytic oxidation (PEO) method. The corrosion, stress corrosion cracking (SCC) and nano-mechanical behaviors were examined by means of potentiodynamic polarization, slow strain rate test (SSRT) and nano-indentation tests. Potentiodynamic polarization (PP) was used to evaluate the corrosion resistance of the coating and slow strain rate test (SSRT) was used for evaluating the environmental cracking resistance in 3.5% NaCl solution. The mechanical properties (hardness and elastic modulus) were obtained from each indentation as a function of the penetration depth across the coating cross section. The above results were compared with similar PEO coated aluminum and magnesium alloys. Results indicated that PEO coating on AA7020 alloy significantly improved the corrosion resistance. However the environmental cracking resistance was found to be only marginal. The hardness and elastic modulus values were found to be much higher when compared to the base metal and similar PEO coated 7075 aluminum alloys. The fabricated coating also exhibited good adhesive strength with the substrate similar to other PEO coated aluminum alloys reported in the literature.

  2. Morphological and chemical evaluation of bone with apatite-coated Al2O3 implants as scaffolds for bone repair

    Directory of Open Access Journals (Sweden)

    A. L. M. Maia F.

    2013-12-01

    Full Text Available The clinical challenge in the reconstruction of bone defects has stimulated several studies in search of alternatives to repair these defects. The ceramics are considered as synthetic scaffolds and are used in dentistry and orthopedics. This study aimed to evaluate by micro energy-dispersive X-ray fluorescence spectrometry (µ-EDXRF and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS, the influence of uncoated and apatite-coated Al2O3 implants on bone regeneration. Twelve samples of Al2O3 implants were prepared and half of this samples (n = 6 were apatite-coated by the modified biomimetic method and then the ceramic material were implanted in the tibia of rabbits. Three experimental groups were tested: Group C - control, surgery procedure without ceramic implant, Group Ce - uncoated Al2O3 implants (n = 6 and Group CeHA - apatite-coated Al2O3 implants (n = 6. The deposition of bone tissue was determined by measuring the weight content of Ca and P through surface mapping of bone-implant interface by µ-EDXRF and through point analysis by EDS. It was observed after thirty days of treatment a greater deposition of Ca and P in the group treated with CeHA (p <0.001 compared to group C. The results suggest that ceramic coated with hydroxyapatite (CeHA can be an auxiliary to bone deposition in tibia defect model in rabbits.

  3. Radiologic evaluation of bone loss at implants with biocide coated titanium abutments: a study in the dog.

    Science.gov (United States)

    López-Píriz, Roberto; Solá-Linares, Eva; Granizo, Juan J; Díaz-Güemes, Idohia; Enciso, Silvia; Bartolomé, José F; Cabal, Belén; Esteban-Tejeda, Leticia; Torrecillas, Ramón; Moya, José S

    2012-01-01

    The objective of the present study is to evaluate bone loss at implant abutments coated with a soda-lime glass containing silver nanoparticles subjected to experimental peri-implantitis. Five beagle dogs were used in the experiments, 3 implants were installed in each quadrant of the mandibles. Glass/n-Ag coted abutments were connected to implant platform. Cotton floss ligatures were placed in a submarginal position around the abutment necks and the animals were subject to a diet which allowed plaque accumulation, and after 15 weeks the dogs were sacrificed. Radiographs of all implant sites were obtained at the beginning and at the end of the experimentally induced peri-implantitis. The radiographic examination indicated that significant amounts of additional bone loss occurred in implants without biocide coating, considering both absolute and relative values of bone loss. Percentages of additional bone loss observed in implants dressed with a biocide coated abutment were about 3 times lower (p<0.006 distal aspect; and p<0.031 at mesial aspect) than the control ones. Within the limits of the present study it seems promising the use of soda-lime glass/nAg coatings on abutments to prevent peri-implant diseases.

  4. Radiologic evaluation of bone loss at implants with biocide coated titanium abutments: a study in the dog.

    Directory of Open Access Journals (Sweden)

    Roberto López-Píriz

    Full Text Available The objective of the present study is to evaluate bone loss at implant abutments coated with a soda-lime glass containing silver nanoparticles subjected to experimental peri-implantitis. Five beagle dogs were used in the experiments, 3 implants were installed in each quadrant of the mandibles. Glass/n-Ag coted abutments were connected to implant platform. Cotton floss ligatures were placed in a submarginal position around the abutment necks and the animals were subject to a diet which allowed plaque accumulation, and after 15 weeks the dogs were sacrificed. Radiographs of all implant sites were obtained at the beginning and at the end of the experimentally induced peri-implantitis. The radiographic examination indicated that significant amounts of additional bone loss occurred in implants without biocide coating, considering both absolute and relative values of bone loss. Percentages of additional bone loss observed in implants dressed with a biocide coated abutment were about 3 times lower (p<0.006 distal aspect; and p<0.031 at mesial aspect than the control ones. Within the limits of the present study it seems promising the use of soda-lime glass/nAg coatings on abutments to prevent peri-implant diseases.

  5. Tribological study of hard coatings without cobalt intended to isolation components of PWR primary cooling system; Etude tribologique de revetements durs sans cobalt destines aux organes d`isolement du circuit primaire des REP

    Energy Technology Data Exchange (ETDEWEB)

    Cachon, L.

    1995-10-18

    The objective is to qualify coatings without cobalt to replace ``Stellites`` coatings in isolation valves of PWR primary cooling system, as Co is activated when passing in the reactor core and contaminated the cooling loop. Three families of coatings were tested: PVD thin films from 1 to 8 {mu}m monolayers of Cr/C{sub x} with x varying between 1.6 and 9.5 at% or multilayers of pure chromium and Cr/C{sub 1.6} at%, coatings with a thickness between 100 and 200 {mu}m of cermets NiCr{sub y} (y varying from 5 to 35 at%) matrix binding chromium or tungsten carbides, and thick coatings 2 mm thickness of cermets Nitronic 60 or Inconel 625 matrix binding 10, 20 or 30% titanium or niobium carbides. Stellite 6 (2 mm) is the reference coating for tribology. Coatings were qualified and selected by thermal shocks, corrosion and plane friction. The thin film and the thick families were disqualified by their destruction or by their high friction coefficient. Then coatings between 100 and 200 {mu}m were used in a valve mock-up working in PWR primary cooling system pressure and temperature conditions. Tests show that these coatings have better wear or tightness performances than stellite 6, except for a slightly higher friction coefficient. (A.B.).

  6. Fabrication and biological evaluation of chitosan coated hyaluronic acid-docetaxel conjugate nanoparticles in CD44(+) cancer cells.

    Science.gov (United States)

    Shabani Ravari, Nazanin; Goodarzi, Navid; Alvandifar, Farhad; Amini, Mohsen; Souri, Effat; Khoshayand, Mohammad Reza; Hadavand Mirzaie, Zahra; Atyabi, Fatemeh; Dinarvand, Rassoul

    2016-07-29

    Hyaluronic acid (HA) has been used for target-specific drug delivery because of strong affinity to CD44, a marker in which overexpressed in cancer cells and cancer stem cells. Conjugation of HA to the cytotoxic agents via active targeting can improve efficacy, biodistribution, and water solubility. To be able to benefit from passive targeting as well, a nanoparticulate system by counter ion using a polycation like chitosan may lead to a perfect delivery system. Water soluble Hyaluronic acid-Docetaxel (HA-DTX) conjugate was prepared and used to formulate chitosan-coated HA-DTX nanoparticles by polyelectrolyte complex (PEC) method and optimized using Box-Behnken design. Biological evaluation of nanoparticles was done in CD44+ cancer cells. Biological evaluation of optimized formula showed IC50 of nanoparticles for 4 T1 and MCF-7 cell lines were 45.34 μM and 354.25 μM against 233.8 μM and 625.9 μM for DTX, respectively with increased cellular uptake showed by inverted confocal microscope. Chitosan-coated HA-DTX nanoparticles were more effective against CD44+ cells than free DTX. Chitosan coated hyaluronic acid-docetaxel conjugate nanoparticles fabricated and evaluated in CD44+ cancer cells.

  7. In vitro evaluation of novel antimicrobial coatings for surgical sutures using octenidine.

    Science.gov (United States)

    Obermeier, A; Schneider, J; Föhr, P; Wehner, S; Kühn, K-D; Stemberger, A; Schieker, M; Burgkart, R

    2015-09-24

    Sutures colonized by bacteria represent a challenge in surgery due to their potential to cause surgical site infections. In order to reduce these type of infections antimicrobially coated surgical sutures are currently under development. In this study, we investigated the antimicrobial drug octenidine as a coating agent for surgical sutures. To achieve high antimicrobial efficacy and required biocompatibility for medical devices, we focused on optimizing octenidine coatings based on fatty acids. For this purpose, antimicrobial sutures were prepared with either octenidine-laurate or octenidine-palmitate at 11, 22, and 33 μg/cm drug concentration normalized per length of sutures. Octenidine containing sutures were compared to the commercial triclosan-coated suture Vicryl® Plus. The release of octenidine into aqueous solution was analyzed and long-term antimicrobial efficacy was assessed via agar diffusion tests using Staphylococcus aureus. For determining biocompatibility, cytotoxicity assays (WST-1) were performed using L-929 mouse fibroblasts. In a 7 days elution experiment, octenidine-palmitate coated sutures demonstrated much slower drug release (11 μg/cm: 7%; 22 μg/cm: 5%; 33 μg/cm: 33%) than octenidine-laurate sutures (11 μg/cm: 82%; 22 μg/cm: 88%; 33 μg/cm: 87%). Furthermore sutures at 11 μg/cm drug content were associated with acceptable cytotoxicity according to ISO 10993-5 standard and showed, similar to Vicryl® Plus, relevant efficacy to inhibit surrounding bacterial growth for up to 9 days. Octenidine coated sutures with a concentration of 11 μg/cm revealed high antimicrobial efficacy and biocompatibility. Due to their delayed release, palmitate carriers should be preferred. Such coatings are candidates for clinical testing in regard to their safety and efficacy.

  8. Microstructural, Micro-hardness and Sensitization Evaluation in HAZ of Type 316L Stainless Steel Joint with Narrow Gap Welds

    Energy Technology Data Exchange (ETDEWEB)

    Islam, Faisal Shafiqul; Jang, Changheui [KAIST, Daejeon (Korea, Republic of); Kang, Shi Chull [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2015-10-15

    From Micro-hardness measurement HAZ zone was found approximately 1-1.5 mm in NGW and DL-EPR test confirmed that 316L NGW HAZ was not susceptible to sensitization as DOS <1% according to sensitization criteria based on reference. In nuclear power plants 316L stainless steels are commonly used material for their metallurgical stability, high corrosion resistance, and good creep and ductility properties at elevated temperatures. Welding zone considered as the weakest and failure initiation source of the components. For safety and economy of nuclear power plants accurate and dependable structural integrity assessment of main components like pressure vessels and piping are need as it joined by different welding process. In similar and dissimilar metal weld it has been observed that weld microstructure cause the variation of mechanical properties through the thickness direction. In the Heat Affected Zone (HAZ) relative to the fusion line face a unique thermal experience during welding.

  9. Evaluation of Environmental Conditions on the Curing Of Commercial Fixative and Intumescent Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Nicholson, J. C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2017-01-10

    Performance metrics for evaluating commercial fixatives are often not readily available for important parameters that must be considered per the facility safety basis and the facility Basis for Interim Operations (BIO). One such parameter is the behavior of such materials in varied, “non-ideal” conditions where ideal is defined as 75 °F, 40% RH. Coupled with the inherent flammable nature of the fixative materials that can act to propagate flame along surfaces that are otherwise fireproof (concrete, sheet metal), much is left unknown when considering the safety basis implications for introducing these materials into nuclear facilities. Through SRNL’s efforts, three (3) fixatives, one (1) decontamination gel, and six (6) intumescent coatings were examined for their responses to environmental conditions to determine whether these materials were impervious to non-nominal temperatures and humidities that may be found in nuclear facilities. Characteristics that were examined included set-to-touch time, dust free time, and adhesion testing of the fully cured compounds. Of these ten materials, three were two-part epoxy materials while the other seven consisted of only one constituent. The results show that the epoxies tested are unable to cure in sub-freezing temperatures, with the low temperatures inhibiting crosslinking to a very significant degree. These efforts show significant inhibiting of performance for non-nominal environmental conditions, something that must be addressed both in the decision process for a fixative material to apply and per the safety basis to ensure the accurate flammability and material at risk is calculated.

  10. Evaluation of Environmental Conditions on the Curing Of Commercial Fixative and Intumescent Coatings

    Energy Technology Data Exchange (ETDEWEB)

    Nicholson, J. C. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-09-26

    Performance metrics for evaluating commercial fixatives are often not readily available for important parameters that must be considered per the facility safety basis and the facility Basis for Interim Operations (BIO). One such parameter is the behavior of such materials in varied, “non-ideal” conditions where ideal is defined as 75 °F, 40% RH. Coupled with the inherent flammable nature of the fixative materials that can act to propagate flame along surfaces that are otherwise fireproof (concrete, sheet metal), much is left unknown when considering the safety basis implications for introducing these materials into nuclear facilities. Through SRNL’s efforts, three (3) fixatives, one (1) decontamination gel, and six (6) intumescent coatings were examined for their responses to environmental conditions to determine whether these materials were impervious to non-nominal temperatures and humidities that may be found in nuclear facilities. Characteristics that were examined included set-to-touch time, dust free time, and adhesion testing of the fully cured compounds. Of these ten materials, three were two-part epoxy materials while the other seven consisted of only one constituent. The results show that the epoxies tested are unable to cure in sub-freezing temperatures, with the low temperatures inhibiting crosslinking to a very significant degree. These efforts show significant inhibiting of performance for non-nominal environmental conditions, something that must be addressed both in the decision process for a fixative material to apply and per the safety basis to ensure the accurate flammability and material at risk is calculated.

  11. Nanocrystalline coatings properties forecasting

    Science.gov (United States)

    Eremin, E. N.; Yurov, V. M.; Guchenko, S. A.; Laurynas, V. Ch

    2017-06-01

    The paper considers various properties of nanocrystalline coatings. The methods of determining the surface tension of the deposited coating on the basis of the size dependence of their physical properties. It is shown that predict the mechanical properties of the coatings, their melting point, heat resistance, wear resistance, corrosion resistance, etc. It can be based on a theoretical evaluation of the surface tension.

  12. PIT Coating Requirements Analysis

    Energy Technology Data Exchange (ETDEWEB)

    MINTEER, D.J.

    2000-10-20

    This study identifies the applicable requirements for procurement and installation of a coating intended for tank farm valve and pump pit interior surfaces. These requirements are intended to be incorporated into project specification documents and design media. This study also evaluates previously recommended coatings and identifies requirement-compliant coating products.

  13. Evaluating the interaction of 308-nm xenon chloride excimer laser with human dentin and enamel hard tissues

    Directory of Open Access Journals (Sweden)

    Mahshid Yaghmaeian-Mahabadi

    2017-11-01

    Full Text Available Background: The pulsed output of the 308 nm XeCl laser and its photoablation action rather than photothermal action offers the ability to remove dental hard tissues with minimal generation of heat in the tissue. Materials and Methods: A total of 20 human molar teeth (ten teeth used as enamel samples and ten teeth used as dentin samples after removing the enamel tissue from their crowns were irradiated by the laser. The crown of each sample was regarded as a cube which its lateral sides were exposed in 2Hz frequency without water cooling. Also, 18 holes for all enamel samples and 18 holes for all dentin samples were obtained. Three different amounts of energy were selected as a variable factor with 6 different numbers of pulses in each energy. The images of these holes were prepared by optic and computer combining, and the amounts of the ablation depth and effective ablation area were calculated using the MATLAB software. Results: The amounts of ablation depth were increased with increasing the number of pulses for both enamel and dentin tissues. The amounts of ablation depth were also increased with increasing the amounts of energy for both enamel and dentin tissues. The greater amounts of ablation depth and effective ablation area were observed in the dentin tissue rather than the enamel tissue. The borders of created holes were reported sharp and clear. Conclusion: The application of the XeCl laser for hard tissue removal and cavity preparation can be possible after some certain modifications.

  14. Nanostructured thin films and coatings mechanical properties

    CERN Document Server

    2010-01-01

    The first volume in "The Handbook of Nanostructured Thin Films and Coatings" set, this book concentrates on the mechanical properties, such as hardness, toughness, and adhesion, of thin films and coatings. It discusses processing, properties, and performance and provides a detailed analysis of theories and size effects. The book presents the fundamentals of hard and superhard nanocomposites and heterostructures, assesses fracture toughness and interfacial adhesion strength of thin films and hard nanocomposite coatings, and covers the processing and mechanical properties of hybrid sol-gel-derived nanocomposite coatings. It also uses nanomechanics to optimize coatings for cutting tools and explores various other coatings, such as diamond, metal-containing amorphous carbon nanostructured, and transition metal nitride-based nanolayered multilayer coatings.

  15. Evaluation of superparamagnetic and biocompatible properties of mesoporous silica coated cobalt ferrite nanoparticles synthesized via microwave modified Pechini method

    Energy Technology Data Exchange (ETDEWEB)

    Gharibshahian, M. [Faculty of New Sciences and Technologies, Semnan University, Semnan (Iran, Islamic Republic of); Mirzaee, O., E-mail: O_mirzaee@semnan.ac.ir [Faculty of Materials and Metallurgical Engineering, Semnan University, Semnan (Iran, Islamic Republic of); Nourbakhsh, M.S. [Faculty of New Sciences and Technologies, Semnan University, Semnan (Iran, Islamic Republic of)

    2017-03-01

    Cobalt ferrite nano particles were synthesized by Pechini sol-gel method and calcined at 700 °C in electrical and microwave furnace. The microwave calcined sample was coated with mesoporous silica by hydrothermal method. Characterization was performed by XRD, FESEM, TEM, VSM, BET and FTIR analysis. The cytotoxicity was evaluated by MTT assay with 3T3 fibroblast cells. The XRD and FTIR results confirmed spinal formation in both cases and verified the formation of silica coating on the nanoparticles. For microwave calcination, The XRD and SEM results demonstrated smaller and flat adhesion forms of nanoparticles with the average size of 15 nm. The VSM results demonstrated nearly superparamagnetic nanoparticles with significant saturation magnetization equal to 64 emu/g. By coating, saturation magnetization was decreased to 36 emu/g. Moreover, the BET results confirmed the formation of mesoporous coating with the average pore diameters of 2.8 nm and average pore volume of 0.82 cm{sup 3} g{sup −1}. Microwave calcined nanoparticles had the best structural and magnetic properties. - Highlights: • CoFe{sub 2}O{sub 4} nanoparticles were synthesized using the microwave modified Pechini method. • The Effect of calcination route and silica coating on NPs properties was studied. • The nearly superparamagnetic nanoparticles were achieved by microwave calcination. • MFC NPs had the best magnetic properties and MTT assay showed no toxicity for MFC-MSC NPs. • A useful scheme was designed to achieve biological superparamagnetic core/shell NPs.

  16. Preparation of Metal Coatings on Steel Balls Using Mechanical Coating Technique and Its Process Analysis

    Directory of Open Access Journals (Sweden)

    Liang Hao

    2017-04-01

    Full Text Available We successfully applied mechanical coating technique to prepare Ti coatings on the substrates of steel balls and stainless steel balls. The prepared samples were analyzed by X-ray diffraction (XRD and scanning electron microscopy (SEM. The weight increase of the ball substrates and the average thickness of Ti coatings were also monitored. The results show that continuous Ti coatings were prepared at different revolution speeds after different durations. Higher revolution speed can accelerate the formation of continuous Ti coatings. Substrate hardness also markedly affected the formation of Ti coatings. Specifically, the substance with lower surface hardness was more suitable as the substrate on which to prepare Ti coatings. The substrate material plays a key role in the formation of Ti coatings. Specifically, Ti coatings formed more easily on metal/alloy balls than ceramic balls. The above conclusion can also be applied to other metal or alloy coatings on metal/alloy and ceramic substrates.

  17. Formulation and evaluation of novel coated floating tablets of bergenin and cetirizine dihydrochloride for gastric delivery.

    Science.gov (United States)

    He, Shuang; Li, Feng; Zhou, Dan; Du, Junrong; Huang, Yuan

    2012-10-01

    A novel coated gastric floating drug-delivery system (GFDDS) of bergenin (BN) and cetirizine dihydrochloride (CET) was developed. First, the pharmacodynamic studies were performed and the results revealed that the new compounds of bergenin/cetirizine dihydrochloride had comparative efficacy as commercial products (bergenin/chlorphenamine maleate) but with fewer side effects on central nervous system (CNS). Subsequently, bergenin was formulated as an extended-release core tablet while cetirizine dihydrochloride was incorporated into the gastric coating film for immediate release. The formulation of GFDDS was optimized by CET content uniformity test, in vitro buoyancy and drug release. Herein, the effects of sodium bicarbonate (effervescent), hydroxypropyl methylcellulose (HPMC, matrix polymer) and coating weight gain were investigated respectively. The optimized GFDDS exhibited good floating properties (buoyancy lag time 10 h) and satisfactory drug-release profiles (immediate release of CET in 10 min and sustained release of BN for 12 h). In vivo gamma scintigraphy proved that the optimized GFDDS could retain in the stomach with a prolonged gastric retention time (GRT) of 5 h, and the coating layer showed no side effect for gastric retention. The novel coated gastric floating drug-delivery system offers a new approach to enhance BN's absorption at its absorption site and the efficacy of both CET and BN.

  18. Coatings of titanium substrates with xCaO·(1 − x)SiO{sub 2} sol–gel materials: characterization, bioactivity and biocompatibility evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Catauro, M., E-mail: michelina.catauro@unina2.it; Papale, F.; Bollino, F.

    2016-01-01

    The objective of this study has been to develop low temperature sol–gel coatings to modify the surface of commercially pure titanium grade 4 (a material generally used in dental application) and to evaluate their bioactivity and biocompatibility on the substrate. Glasses of composition expressed by the following general formula xCaO·(1 − x)SiO{sub 2} (0.0 < x < 0.60) have been prepared by means of the sol–gel route starting from tetraethyl orthosilicate and calcium nitrate tetrahydrate. Those materials, still in the sol phase, have been used to coat titanium substrates by means of the dip-coating technique. Fourier transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) allowed the materials to be characterized and a microstructural analysis of the coatings obtained was performed using scanning electron microscopy (SEM). The potential applications of the coatings in the biomedical field were evaluated by bioactivity and biocompatibility tests. The coated titanium was immersed in simulated body fluid (SBF) for 21 days and the hydroxyapatite deposition on its surface was subsequently evaluated via SEM–EDXS analysis, as an index of bone-bonding capability. To investigate cell-material interactions, mouse embryonic fibroblast cells (3 T3) were seeded onto the specimens and the cell viability was evaluated by a WST-8 assay. - Highlights: • CaO/SiO{sub 2} biomaterials synthesized by sol–gel method at various molar ratio • Coating of titanium substrate with dip-coating technology • Chemical and morphological characterization of materials and coating • Biocompatibility and bioactivity improvement of coated titanium.

  19. Evaluation and comparison of aluminum-coated pumice and zeolite in arsenic removal from water resources

    Directory of Open Access Journals (Sweden)

    Heidari Masoumeh

    2012-12-01

    Full Text Available Abstract In this research the potential of aluminum-coated pumice and zeolite in arsenic, As (V removal was investigated and compared. Scanning Electron Microscopy (SEM, X-Ray Diffraction (XRD and X-Ray Flaorescence Spectrometry (XRF were carried out to determine the properties of the adsorbents. Several parameters including adsorbent dosage] pH, contact time, and initial As(V concentration were studied. The optimum pH obtained for both adsorbents was pH = 7. As(V adsorption by both adsorbents followed the Freundlich isotherm (for aluminum-coated pumice and zeolite respectively with R2 > 0.98 and R2 > 0.99. The obtained data from kinetics showed that the pseudo-second order model could better explain As(V adsorption for both aluminum-coated pumice and zeolite (R2 > 0.98 and R2 > 0.99 respectively. Because of low cost, both adsorbents may be economically used, but aluminum-coated zeolite showed high efficiency of, due to its porosity and surface area. More than 96% of As(V with initial concentration of 250 μg/L was removed by 10 g/L aluminum-coated zeolite at pH = 7 and in 60 minutes to achieve As(V concentration of 10 μg/L, while only 71% of As(V could be removed by aluminum-coated pumice.

  20. Effect of addition of Ag nano powder on mechanical properties of epoxy/polyaminoamide adduct coatings filled with conducting polymer

    Energy Technology Data Exchange (ETDEWEB)

    Samad, Ubair Abdus [Department of Chemical Engineering, College of Engineering, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Center of excellence for research in engineering materials (CEREM), Advance Manufacturing Institute, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Khan, Rawaiz [Department of Chemical Engineering, College of Engineering, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Alam, Mohammad Asif [Center of excellence for research in engineering materials (CEREM), Advance Manufacturing Institute, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Al-Othman, Othman Y. [Department of Chemical Engineering, College of Engineering, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); Deanship of Graduate Studies, The Saudi Electric University, P. O. Box 93499, Riyadh 11673 (Saudi Arabia); Al-Zahrani, Saeed M. [Center of excellence for research in engineering materials (CEREM), Advance Manufacturing Institute, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia); SABIC Polymer Research Center (SPRC) and department of chemical engineering, college of engineering, King Saud University, P. O. Box 800, Riyadh 11421 (Saudi Arabia)

    2015-05-22

    In this study the effect of Ag Nano powder on mechanical properties of epoxy coatings filled with optimized ratio of conducting polymers (Polyaniline and Polyppyrole) was evaluated. Bisphenol A diglycidyl ether epoxy resin (DGEBA) along with polyaminoamide adduct (ARADUR 3282-1 BD) is used as curing agent under optimized stoichiometry values. Curing is performed at room temperature with different percentages of Nano filler. Glass and steel panels were used as coating substrate. Bird applicator was used to coat the samples in order to obtain thin film with wet film thickness (WFT) of about 70-90 µm. The samples were kept in dust free environment for about 7 days at room temperature for complete curing. The coated steel panels were used to evaluate the mechanical properties of coating such as hardness, scratch and impact tests whereas coated glass panels were used for measuring pendulum hardness of the coatings. To check the dispersion and morphology of Nano filler in epoxy matrix scanning electron microscopy (SEM) was used in addition Nano indentation was also performed to observe the effect of Nano filler on modulus of elasticity and hardness at Nano scale.

  1. Preparation and evaluation of PEGylated phospholipid membrane coated layered double hydroxide nanoparticles

    Directory of Open Access Journals (Sweden)

    Mina Yan

    2016-06-01

    Full Text Available The aim of the present study was to develop layered double hydroxide (LDH nanoparticles coated with PEGylated phospholipid membrane. By comparing the size distribution and zeta potential, the weight ratio of LDH to lipid materials which constitute the outside membrane was identified as 2:1. Transmission electron microscopy photographs confirmed the core-shell structure of PEGylated phospholipid membrane coated LDH (PEG-PLDH nanoparticles, and cell cytotoxicity assay showed their good cell viability on Hela and BALB/C-3T3 cells over the concentration range from 0.5 to 50 μg/mL.

  2. Design and evaluation of dry-coated tablets for colonic delivery of diclofenac sodium

    OpenAIRE

    Sanna, Vanna Annunziata; Gavini, Elisabetta; Rassu, Giovanna; Pirisino, Gerolamo Antonio; Giunchedi, Paolo

    2006-01-01

    A colonic drug delivery system is required to protect a drug during its transit through the upper gastro-intestinal tract and allow its release in the colon. The aim of this study was the preparation of dry-coated tablets designed for colonic release of the model drug Diclofenac sodium (DS). The system consists of a drug-pectine (PC) mixture as the core and hydroxypropylmethylcellulose (HPMC) alone or mixed in different ratios with poly(ε-caprolactone) (CL) as the coat layer.

  3. Improving tribological properties of (Zn–Ni)/nano Al{sub 2}O{sub 3} composite coatings produced by ultrasonic assisted pulse plating

    Energy Technology Data Exchange (ETDEWEB)

    Ataie, Sayed Alireza, E-mail: ataie_s_alireza@metaleng.iust.ac.ir; Zakeri, Alireza

    2016-07-25

    In this study pulse electroplating was used to deposit the composite coating of (Zn–Ni) strengthened by Al{sub 2}O{sub 3} nanoparticles on mild steel plate. The effect of Al{sub 2}O{sub 3} fraction and ultrasonic irradiation on the properties of the composite coating was also investigated. Scanning electron microscopy and energy dispersive spectroscopy techniques were employed to characterize the morphology and composition of the coating. Topography and surface roughness were investigated by atomic force microscopy. Also in order to evaluate the mechanical properties of the coating micro hardness and wear tests were conducted. It was found that coating hardness was increased from 538 HV to 750 HV and friction coefficient was decreased from 0.588 to 0.392. Results revealed that tribological properties of coating could be improved significantly by using suitable ultrasonic intensity simultaneously with pulse plating. - Highlights: • SEM indicated on the elimination of cracks and pores when ultrasounds were used. • XRD result showed nano sized grains of Zn–Ni matrix was developed in this research. • Simultaneous pulse plating and ultrasonic conditions improved the properties of the coating. • A (Zn–Ni)/nano alumina uniform composite coating for especial applications was developed. • Micro hardness and wear behavior of the coating was modified by intensifying the ultrasound.

  4. Evaluation of WC-9Co-4Cr laser surface alloyed coatings on stainless steel

    CSIR Research Space (South Africa)

    Obadele, A

    2011-07-01

    Full Text Available spectrometer (EDS), while the phase changed were observed using x-ray diffraction (XRD). The surface hardness was determined using the Vickers microhardness tester. The decomposition of WC-9Co-4Cr into W2C, C and W is as a result of low heat of formation of WC...

  5. Guar gum and hydroxy propyl methylcellulose compressed coated tablets for colonic drug delivery: in vitro and in vivo evaluation in healthy human volunteers.

    Science.gov (United States)

    Hashem, F M; Shaker, D S; Nasr, M; Saad, I E; Ragaey, R

    2011-04-01

    The objectives of the present study are to evaluate guar gum in combination with hydroxyl propyl methylcellulose (HPMC) as compression coat for colonic delivery of prednisolone as well as improving the mechanical properties of the compressed coated tablets. The core tablets containing 5 mg prednisolone were compression coated with 125 mg of coating materials consisted of guar gum alone or mixtures of guar gum in combination with different ratios of HPMC. The compressed coated tablets were evaluated for their mechanical properties, in vitro drug release and in vivo performance in human volunteers. The compressed coated tablets with coats containing HPMC exhibited acceptable mechanical properties. In vitro drug release studies in pH 7.4 phosphate-buffered saline medium containing 2% (w/v) rat caecal content have shown that increase in concentration of HPMC in the prepared coats from 10% to 20% resulted in an increase in the release rate. However, further increase in HPMC concentration to constitute 30% caused a reduction in the release rate. Based on the drug release results, tablets coated with coat consisted of 80% guar gum and 20% HPMC were selected for in vivo evaluation. In vivo gamma scintigraphic study on human volunteers using technetium-99m-diethylenetriamine pentaacetic acid as a tracer was performed. The results showed that tablets remained intact in stomach and small intestine, however partial and complete release of the tracer occurred in the colon. In conclusion, guar gum in combination with HPMC would be successfully used as a carrier for drug delivery to the colon.

  6. Evaluation of band offset at amorphous-Si/BaSi{sub 2} interfaces by hard x-ray photoelectron spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Takabe, Ryota; Takeuchi, Hiroki; Du, Weijie; Toko, Kaoru; Suemasu, Takashi [Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Ito, Keita [Institute of Applied Physics, University of Tsukuba, Tsukuba, Ibaraki 305-8573 (Japan); Japan Society for the Promotion of Science (JSPS), Chiyoda, Tokyo 102-0083 (Japan); Department of Electronic Engineering, Graduate School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Ueda, Shigenori [Synchrotron X-Ray Station at SPring-8, National Institute for Materials Science (NIMS), Sayo, Hyogo 679-5148 (Japan); Quantum Beam Unit, NIMS, Tsukuba, Ibaraki 305-0047 (Japan); Kimura, Akio [Graduate School of Science, Hiroshima University, Higashi-Hiroshima 739-8526 (Japan)

    2016-04-28

    The 730 nm-thick undoped BaSi{sub 2} films capped with 5 nm-thick amorphous Si (a-Si) intended for solar cell applications were grown on Si(111) by molecular beam epitaxy. The valence band (VB) offset at the interface between the BaSi{sub 2} and the a-Si was measured by hard x-ray photoelectron spectroscopy to understand the carrier transport properties by the determination of the band offset at this heterointerface. We performed the depth-analysis by varying the take-off angle of photoelectrons as 15°, 30°, and 90° with respect to the sample surface to obtain the VB spectra of the BaSi{sub 2} and the a-Si separately. It was found that the barrier height of the a-Si for holes in the BaSi{sub 2} is approximately −0.2 eV, whereas the barrier height for electrons is approximately 0.6 eV. This result means that the holes generated in the BaSi{sub 2} layer under solar radiation could be selectively extracted through the a-Si/BaSi{sub 2} interface, promoting the carrier separation in the BaSi{sub 2} layer. We therefore conclude that the a-Si/BaSi{sub 2} interface is beneficial for BaSi{sub 2} solar cells.

  7. Evaluation of the Fast-Electron Source Function for Two-Plasmon Decay from Temporal Hard X-Ray Emission

    Science.gov (United States)

    Delettrez, J. A.; Follett, R. K.; Myatt, J. F.; Stoeckl, C.

    2016-10-01

    The modeling of the fast-electron transport in the 1-D hydrodynamic code LILAC requires the description of the source electrons as a function of time. The particle-in-cell code OSIRIS and the interaction code FPSE provide some guidance but have not provided an algorithm for the energy fraction from the laser pulse as the coronal parameters change with time. The original algorithm, based on the measured hard x-ray (HXR) emission as a function of laser intensity, depended exponentially on the two-plasmon-decay threshold parameter up to about 0.9 and saturates above it. This algorithm along with FPSE simulations produced HXR emissions much earlier than observed. Analysis of the measured HXR emissions from implosions with near-constant threshold parameter values show that the rise time of the emission can be described with an exponential curve with roughly a rise time of 200 ps. Trial and error set the start of the rise at the threshold value of 0.75. Causes for this rise time will be discussed. Comparison between measured and computed HXR emissions for different implosion scenarios will be presented, including those for cryogenic targets. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  8. Evaluation of a new hardness tester (Cariotester): Comparison with transverse microradiography for assessing the inhibitory effect of fluoride application on bovine root dentin demineralization.

    Science.gov (United States)

    Sugawara, Toyotaro; Nakashima, Syozi; Shimizu, Akihiko; Tagami, Junji; Momoi, Yasuko

    2015-01-01

    The objective of this study was to investigate the correlation between CT depth, indentation depth determined by a new hardness tester (Cariotester), and the transverse microradiography (TMR) parameters, i.e., lesion depth and mineral loss. For that purpose, this study evaluated the feasibility of using Cariotester as a root caries diagnostic system and capability of Cariotester to detect effect of fluoride application on inhibiting dentin demineralization. Fluorides were applied to bovine root dentin specimens, which were subsequently demineralized for 1-21 days and then CT depth and TMR parameters were assessed. There were significant correlations between CT depth and TMR parameters in fluoride and non-fluoride groups. There were significant differences between fluoride and non-fluoride groups for CT depth and TMR parameters respectively. Current results suggested that Cariotester may be capable of providing an objective evaluation of root caries progression and the fluoride effect on inhibiting dentin demineralization.

  9. Mechanical and microstructural evaluation of laser assisted cold sprayed bioceramic coatings: potential use for biomedical applications

    CSIR Research Space (South Africa)

    Tlotleng, Monnamme

    2014-02-01

    Full Text Available Coatings of commercial pure titanium (CP)-Ti and HAP bio-ceramic were synthesised on Ti-6Al-4V substrate using laser assisted cold spray (LACS) deposition technique. The LACS system comprised of 4.4 kW Nd:YAG laser system, AT-12000HPHV 5000PSI (35...

  10. Enteric-coated sustained-release nanoparticles by coaxial electrospray: preparation, characterization, and in vitro evaluation

    Science.gov (United States)

    Hao, Shilei; Wang, Bochu; Wang, Yazhou; Xu, Yingqian

    2014-02-01

    Enteric-coated formulations can delay the release of drugs until they have passed through the stomach. However, high concentration of drugs caused by rapidly released in the small intestine leads to the intestinal damage, and frequent administration would increase the probability of missing medication and reduce the patient compliance. To solve the above-mentioned problems, aspirin-loaded enteric-coated sustained-release nanoparticles with core-shell structure were prepared via one-step method using coaxial electrospray in this study. Eudragit L100-55 as pH-sensitive polymer and Eudragit RS as sustained-release polymer were used for the outer coating and inner core of the nanoparticles, respectively. The maximum loading capacity of nanoparticles was 23.66 % by changing the flow rate ratio of outer/inner solutions, and the entrapment efficiency was nearly 100 %. Nanoparticles with core-shell structure were observed via fluorescence microscope and transmission electron microscope. And pH-sensitive and sustained drug release profiles were observed in the media with different pH values (1.2 and 6.8). In addition, mild cytotoxicity in vitro was detected, and the nanoparticles could be taken up by Caco-2 cells within 1.0 h in cellular uptake study. These results indicate that prepared enteric-coated sustained-release nanoparticles would be a more safety and effective carrier for oral drug delivery.

  11. Surface characterization and effectiveness evaluation of anti-graffiti coatings on highly porous stone materials

    Science.gov (United States)

    Lettieri, Mariateresa; Masieri, Maurizio

    2014-01-01

    In this study, two commercial sacrificial anti-graffiti systems, provided as water emulsion, were applied on a highly porous stone. The behavior of the anti-graffiti treatments was investigated by means of differential scanning calorimetry (DSC), Fourier transform infrared spectroscopy in attenuated total reflectance mode (ATR-FTIR), colorimetric tests, and water static contact angle measurements. The presence of a protective coating enhanced the removal of paint sprayed on the stone. However, penetration of the staining agent below the surface, due to the high porosity of the substrate, caused difficulties in eliminating the paint. In fact, repeated cleaning procedures, involving hot water, mechanical action, and chemical removers, did not allow a complete removal of the paint. The examined systems behaved against graffiti in different ways. No affinity between the wax-based product and the paint was observed; nevertheless, this behavior did not result in good anti-graffiti performances. On the contrary, the penetration of the paint into the fluorine-based coating yielded a good anti-graffiti effectiveness, since the stain was easily eliminated from the surfaces. The anti-graffiti coatings survived in limited areas after the cleaning processes, although the studied compounds are suggested as sacrificial products. Such behavior may affect the maintenance activities, when the surface is no longer protected and the coating need to be renewed, since compatibility problems, as well as harmful accumulation, could occur because of further treatments on these surfaces.

  12. LABORATORY EVALUATION OF NONSTICK COATINGS TO REDUCE INK ADHESION TO PRINTING PRESS COMPONENTS

    Science.gov (United States)

    The report gives results of a project to identify surface coatings or preparations that might reduce and/or eliminate the need for solvent cleaning of ink-feed-system components of printing equipment. The study was designed to provide qualitative, but not quantitative, results. T...

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

    Science.gov (United States)

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

    2014-01-01

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

  14. Rapidly-deposited polydopamine coating via high temperature and vigorous stirring: formation, characterization and biofunctional evaluation.

    Directory of Open Access Journals (Sweden)

    Ping Zhou

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

  15. Evaluation of Antibacterial Effects of Silver-Coated Stainless Steel Orthodontic Brackets

    Directory of Open Access Journals (Sweden)

    Valiollah Arash

    2016-08-01

    Full Text Available Objectives: White spots and enamel demineralization around orthodontic brackets are among the most important complications resulting from orthodontic treatments. Since the antibacterial properties of metals and metallic particles have been well documented, the aim of this study was to assess the antibacterial effect of stainless steel orthodontic brackets coated with silver (Ag particles.Materials and Methods: In this study, 40 standard metal brackets were divided into two groups of 20 cases and 20 controls. The brackets in the case group were coated with Ag particles using an electroplating method. Atomic force microscopy (AFM and scanning electron microscopy (SEM were used to assess the adequacy of the coating process. In addition, antibacterial tests, i.e., disk diffusion and direct contact tests were performed at three, six, 24and 48 hours, and 15 and 30 days using a Streptococcus mutans strain. The results were analyzed using Student’s t-test and repeated measures ANOVA.Conclusions: Brackets coated with Ag, via an electroplating method, exhibited antibacterial properties when placed in direct contact with Streptococcus mutans. This antibacterial effect persisted for 30 days after contact with the bacteria.

  16. EVALUATION OF BARRIERS TO THE USE OF RADIATION CURED COATINGS IN WIDE-WEB FLEXOGRAPHIC PRINTING

    Science.gov (United States)

    The report gives results of a study to investigate and identify the technical, economic, and educational barriers to the use and implementation of radiation-curable coatings (primarily ultraviolet (UV) curable inks) in the wide-web flexographic printing industry. (NOTE: In suppor...

  17. Design and evaluation of enteric-coated tablets for rifampicin and isoniazid combinations.

    Science.gov (United States)

    Wang, Yongjun; Liu, Hongzhuo; Liu, Kai; Sun, Jin; He, Zhonggui

    2013-01-01

    In order to improve the bioavailability of rifampicin (RIF) from rifampicin and isoniazid (INH) combination formulations, the physicochemical characteristics of RIF, stability of RIF in different pH buffers in the presence of INH, as well as the effect of particle size of RIF materials on the dissolution rate were investigated. On the basis of the above examinations, enteric-coated tablets for RIF and INH combinations were designed and prepared. RIF showed low solubility and high apparent distribution coefficient in the intestinal pH (pH 4.0-7.4). With the decrease in pH, the degradation of RIF increase and the presence of INH deepen the degradation. Enteric-coated tablets were prepared after grinding the RIF materials by dry granulation technique. The pharmacokinetics of RIF and INH of self-made enteric-coated tablets in dogs were studied by comparing with the reference tablets. The AUC(0-48) of RIF in both reference and test tablets were 304.77 ± 42.27 and 353.79 ± 31.63 µg·h·mL(-1), respectively. The AUC(0-48) of INH in both reference and test tablets were 17.14 ± 8.59 and 19.62 ± 10.57 µg·h·mL(-1), respectively. Enteric-coated tablets may minimize the decomposition of RIF in gastrointestinal tract and improve the bioavailability.

  18. In vitro evaluation of different heat-treated radio frequency magnetron sputtered calcium phosphate coatings.

    NARCIS (Netherlands)

    Yonggang, Y.; Wolke, J.G.C.; Yubao, L.; Jansen, J.A.

    2007-01-01

    OBJECTIVES: Surface chemical compositions, such as calcium/phosphorus ratio and phase content, have a strong influence on the bioactivity and biocompatibility of calcium phosphate (CaP) coatings as applied on orthopedic and dental implants. MATERIAL AND METHODS: Hydroxylapatite (HA) and dicalcium

  19. SUPER HARD SURFACED POLYMERS

    Energy Technology Data Exchange (ETDEWEB)

    Mansur, Louis K [ORNL; Bhattacharya, R [UES, Incorporated, Dayton, OH; Blau, Peter Julian [ORNL; Clemons, Art [ORNL; Eberle, Cliff [ORNL; Evans, H B [UES, Incorporated, Dayton, OH; Janke, Christopher James [ORNL; Jolly, Brian C [ORNL; Lee, E H [Consultant, Milpitas, CA; Leonard, Keith J [ORNL; Trejo, Rosa M [ORNL; Rivard, John D [ORNL

    2010-01-01

    High energy ion beam surface treatments were applied to a selected group of polymers. Of the six materials in the present study, four were thermoplastics (polycarbonate, polyethylene, polyethylene terephthalate, and polystyrene) and two were thermosets (epoxy and polyimide). The particular epoxy evaluated in this work is one of the resins used in formulating fiber reinforced composites for military helicopter blades. Measures of mechanical properties of the near surface regions were obtained by nanoindentation hardness and pin on disk wear. Attempts were also made to measure erosion resistance by particle impact. All materials were hardness tested. Pristine materials were very soft, having values in the range of approximately 0.1 to 0.5 GPa. Ion beam treatment increased hardness by up to 50 times compared to untreated materials. For reference, all materials were hardened to values higher than those typical of stainless steels. Wear tests were carried out on three of the materials, PET, PI and epoxy. On the ion beam treated epoxy no wear could be detected, whereas the untreated material showed significant wear.

  20. Effect of Reverse Pulse Current Duration on the Corrosion and Wear Performance of Ni-W Nanolaminate Coatings

    Science.gov (United States)

    Shreeram, Devesh Dadhich; Bedekar, Vikram; Li, Shengxi; Jagtap, Rohit; Cong, Hongbo; Doll, Gary L.

    2017-11-01

    The effects of varying the reverse pulse current duration ( τ = 0 s, 1 s, 5 s, and 10 s) were evaluated on the composition, crystallinity, hardness, corrosion resistance, and tribological performance of nanolaminate Ni-W coatings deposited by pulsed reverse current electrodeposition. With the deposition conditions used in this study, it was found that a reverse current duration of τ = 1 s produced a coating that was both highly corrosion resistant and wear resistant.

  1. Niobium pentoxide coating replacing zinc phosphate coating

    OpenAIRE

    RODRIGUES, P.R.P.; TERADA, M.; JUNIOR, O.R.A.; LOPES, A.C.; COSTA, I.; BANCZEK, E.P.

    2015-01-01

    A new coating made of niobium pentoxide, obtained through the sol-gel process, was developed for the carbon steel (SAE 1010). The corrosion protection provided by this coating was evaluated through electrochemical tests such as: open circuit potential, electrochemical impedance spectroscopy and anodic potentiodynamic polarization in NaCl 0,5 mol L-1 solution. The morphology and composition of the coatings were analyzed using scanning electronic microscopy, energy dispersive spectroscopy and X...

  2. Effect of metal coatings on mechanical properties of aluminium alloy

    Science.gov (United States)

    Ravi Kumar, V.; Dileep, B. P.; Mohan Kumar, S.; Phanibhushana, M. V.

    2017-07-01

    This investigation mainly targeted on study of hardness and tensile properties of Al 7075 with different metal coatings like Nickel, Zinc and cadmium. Coating of these metals on Al 7075 is successfully achieved by time dependent electroplating method for different thicknesses of 10, 15 and 20 Microns. These metal coated Al-7075 specimens were tested for hardness and tensile properties according to the ASTM standards. It's found that Nickel coated alloy shows excellent hardness and tensile properties compared to Zinc and Cadmium coated alloys. 20 µm Nickel coated alloy exhibits highest hardness number of 102 HRB and Maximum Tensile Strength of 603 MPa than Zinc and Cadmium coated alloy. The microstructural studies authenticated that the coating of Nickel, zinc and cadmium on Al 7075 is homogeneous.

  3. Electrochemical Evaluation of Hydroxyapatite/ZrN Coated Magnesium Biodegradable Alloy in Ringer Solution as a Simulated Body Fluid

    Directory of Open Access Journals (Sweden)

    Seyed Rahim Kiahosseini

    2015-02-01

    Full Text Available Magnesium alloys as biodegradable materials can be used in body as an implant materials but since they have poor corrosion resistance, it is required to decrease their corrosion rate by biocompatible coatings. In this study, hydroxyapatite (HA coatings in the presence of an intermediate layer of ZrN as a biocompatible material, deposited on AZ91 magnesium alloy by ion beam sputtering method at 300 °C temperature and at different times 180, 240, 300, 360 and 420 min. Then changes in corrosion resistance of samples in Ringer's solution as a solution similar to the human body was evaluated in two ways, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS. To investigate the causes of the destruction of the samples, the surface of samples was studied by scanning electron microscopy (SEM. The results showed that because of porous coatings created, the corrosion potential of the samples was about +55mV higher than the uncoated substrate that by changing the deposition time, was not observed the significant change But with increasing deposition time to 360 min, corrosion current decreased which represents an increase of corrosion resistance of magnesium alloy in body solution. However, a further increase in deposition time to 420 min, due to increase thickness and stress in the layer, the corrosion resistance of the samples was reduced. The results of the EIS confirm the corrosion behavior of the polarization method, too.   

  4. Evaluation of tetraethoxysilane (TEOS) sol-gel coatings, modified with green synthesized zinc oxide nanoparticles for combating microfouling.

    Science.gov (United States)

    Krupa, A Nithya Deva; Vimala, R

    2016-04-01

    Green synthesis of zinc oxide nanoparticles (ZnO-NPs) is gaining importance as an eco-friendly alternative to conventional methods due to its enormous applications. The present work reports the synthesis of ZnO-NPs using the endosperm of Cocos nucifera (coconut water) and the bio-molecules responsible for nanoparticle formation have been identified. The synthesized nanoparticles were characterized using UV-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and Zeta potential measurement. The results obtained reveal that the synthesized nanoparticles are moderately stable with the size ranging from 20 to 80 nm. The bactericidal effect of the nanoparticles was proved by well diffusion assay and determination of minimum inhibitory concentration (MIC) against marine biofilm forming bacteria. Further the green synthesized ZnO-NPs were doped with TEOS sol-gels (TESGs) in order to assess their antimicrofouling capability. Different volumes of liquid sol-gels were coated on to 96-well microtitre plate and cured under various conditions. The optimum curing conditions were found to be temperature 60 °C, time 72 h and volume 200 μl. Antiadhesion test of the undoped (SG) and ZnO-NP doped TEOS sol-gel (ZNSG) coatings were evaluated using marine biofilm forming bacteria. ZNSG coatings exhibited highest biofilm inhibition (89.2%) represented by lowest OD value against Pseudomonasotitidis strain NV1. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Size- and coating-dependent cytotoxicity and genotoxicity of silver nanoparticles evaluated using in vitro standard assays.

    Science.gov (United States)

    Guo, Xiaoqing; Li, Yan; Yan, Jian; Ingle, Taylor; Jones, Margie Yvonne; Mei, Nan; Boudreau, Mary D; Cunningham, Candice K; Abbas, Mazhar; Paredes, Angel M; Zhou, Tong; Moore, Martha M; Howard, Paul C; Chen, Tao

    2016-11-01

    The physicochemical characteristics of silver nanoparticles (AgNPs) may greatly alter their toxicological potential. To explore the effects of size and coating on the cytotoxicity and genotoxicity of AgNPs, six different types of AgNPs, having three different sizes and two different coatings, were investigated using the Ames test, mouse lymphoma assay (MLA) and in vitro micronucleus assay. The genotoxicities of silver acetate and silver nitrate were evaluated to compare the genotoxicity of nanosilver to that of ionic silver. The Ames test produced inconclusive results for all types of the silver materials due to the high toxicity of silver to the test bacteria and the lack of entry of the nanoparticles into the cells. Treatment of L5718Y cells with AgNPs and ionic silver resulted in concentration-dependent cytotoxicity, mutagenicity in the Tk gene and the induction of micronuclei from exposure to nearly every type of the silver materials. Treatment of TK6 cells with these silver materials also resulted in concentration-dependent cytotoxicity and significantly increased micronucleus frequency. With both the MLA and micronucleus assays, the smaller the AgNPs, the greater the cytotoxicity and genotoxicity. The coatings had less effect on the relative genotoxicity of AgNPs than the particle size. Loss of heterozygosity analysis of the induced Tk mutants indicated that the types of mutations induced by AgNPs were different from those of ionic silver. These results suggest that AgNPs induce cytotoxicity and genotoxicity in a size- and coating-dependent manner. Furthermore, while the MLA and in vitro micronucleus assay (in both types of cells) are useful to quantitatively measure the genotoxic potencies of AgNPs, the Ames test cannot.

  6. The Tribological Performance of Hardfaced/ Thermal Sprayed Coatings for Increasing the Wear Resistance of Ventilation Mill Working Parts

    Directory of Open Access Journals (Sweden)

    A. Vencl

    2015-09-01

    Full Text Available During the coal pulverizing, the working parts of the ventilation mill are being worn by the sand particles. For this reason, the working parts are usually protected with materials resistant to wear (hardfaced/thermal sprayed coatings. The aim of this study was to evaluate the tribological performance of four different types of coatings as candidates for wear protection of the mill’s working parts. The coatings were produced by using the filler materials with the following nominal chemical composition: NiFeBSi-WC, NiCrBSiC, FeCrCTiSi, and FeCrNiCSiBMn, and by using the plasma arc welding and flame and electric arc spraying processes. The results showed that Ni-based coatings exhibited higher wear resistance than Fe-based coatings. The highest wear resistance showed coating produced by using the NiFeBSi-WC filler material and plasma transferred arc welding deposition process. The hardness was not the only characteristic that affected the wear resistance. In this context, the wear rate of NiFeBSi-WC coating was not in correlation with its hardness, in contrast to other coatings. The different wear performance of NiFeBSi-WC coating was attributed to the different type and morphological features of the reinforcing particles (WC.

  7. EVALUATION OF ANTIBACTERIAL ACTIVITY OF ZnO NANOPARTICLES COATED SONOCHEMICALLY ONTO TEXTILE FABRICS

    Directory of Open Access Journals (Sweden)

    James Beddow

    2012-08-01

    Full Text Available Growing resistance of microorganisms to potent antibiotics has renewed a great interest towards investigating bactericidal properties of nanoparticles and their nano-composites as an alternative. In the present work studies have been carried out to investigate the antibacterial properties of ZnO nanoparticles (NPs. Various tests were performed to assess the antibacterial activity of cotton fabrics coated with ZnO nanoparticles against Gram positive Staphylococcus aureus and Gram negative Escherichia coli. The antibacterial activities of the fabrics were assessed semi-quantitatively by the agar diffusion method and the shake flask method (nutrient broth and quantitatively by the shake flask method (saline and the absorption method (ISO 20743:2007. The results showed a significant antibacterial activity of ZnO nanoparticles coated onto fabrics against both bacteria, with a slightly higher activity against Staphylococcus aureus as compared to Escherichia coli.

  8. Experimental investigation of thermal barrier (8YSZ-TiO2-Al2O3 coated piston used in direct injection compression ignition engine

    Directory of Open Access Journals (Sweden)

    Muthusamy Jayaram

    2016-01-01

    Full Text Available Thermal barrier coatings are becoming increasingly important in providing protection from high temperature degradation for heat engine components and allow further increase in engine temperatures for higher efficiency. The main objective of this research work is to experimentally investigate the air plasma sprayed yttria stabilized zirconia with addition of titanium oxide and aluminum oxide thermal barrier coating on Al-13% Si piston material. The mechanical properties of the coated and uncoated samples were comparatively analyzed. The test revealed that hardness values of coated samples are ten times higher than the hardness values of uncoated samples. The microstructure and surface morphology of the coating were evaluated by scanning electron microscopy. The delamination behaviour of thermal barrier coating was evaluated by thermal cycle test. Finally, the performance test of the coated and uncoated engine was evaluated with the same engine operating conditions. The brake thermal efficiency is increased by 5.99%. The brake specific fuel consumption was decreased by 0.06 kg/kWh, in TBC engine with 8YSZ + Al2O3 + TiO2. The CO and HC was greatly decreased in thermal barrier coating engine. There was the greater reduction of NOx is observed due to coating because of nitrogen has absorbed by zirconia.

  9. Preparation and evaluation of duloxetine hydrochloride enteric-coated pellets with different enteric polymers

    Directory of Open Access Journals (Sweden)

    Chen Kuang

    2017-05-01

    Full Text Available The main purpose of the present study was to prepare duloxetine hydrochloride (DXH enteric-coated pellets using different enteric polymers. Three layers (drug-loaded layer, barrier layer, and enteric-coated layer were applied to the inert core pellets, successively. The optimal formulation was manufactured by employing suspension layering method in fluidized bed processor (FBP with varieties of enteric polymers like Aqoat® AS-LF, Eudragit® L30D55 and HPMCP-HP55. The prepared pellets were measured for physical characterization and the in vitro dissolution profile. Scanning electron microscopy (SEM was conducted to observe the morphology of pellets, and different kinetic models were applied to analyze the release mechanism of Cymbalta® and home-made pellets. The coating weight gain of enteric-coated layer containing Eudragit® L30D55, Aqoat® AS-LF and HP-55 were determined to be 35%, 26% and 24%, respectively. The similarity factors (f2 of self-made capsules with above polymers and commercially available capsules (Cymbalta® were above 50 in the dissolution medium of pH 6.8 phosphate buffer solution (PBS. SEM figures showed the smooth surfaces of self-prepared pellets using Eudragit® L30D55 and Aqoat® AS-LF, whereas rough surface was found in the HP-55 pellets at day 0, and an impurity was appearing in the condition of 40 °C/75% relative humidity for 1 month. In conclusion, the pellets prepared by utilizing Eudragit® L30D55 and Aqoat® AS-LF were the optimal preparations based on the dissolution profile and stability.

  10. Neural network computation for the evaluation of process rendering: application to thermally sprayed coatings

    Directory of Open Access Journals (Sweden)

    Guessasma Sofiane

    2017-01-01

    Full Text Available In this work, neural network computation is attempted to relate alumina and titania phase changes of a coating microstructure with respect to energetic parameters of atmospheric plasma straying (APS process. Experimental results were analysed using standard fitting routines and neural computation to quantify the effect of arc current, hydrogen ratio and total plasma flow rate. For a large parameter domain, phase changes were 10% for alumina and 8% for titania with a significant control of titania phase.

  11. Study of Scanning Micro-arc Oxidation and Coating Development

    Science.gov (United States)

    Xia, Lingqin; Han, Jianmin; Domblesky, Joseph P.; Yang, Zhiyong; Li, Weijing

    2017-11-01

    Micro-arc oxidation (MAO) continues to be the focus of numerous investigations, whereas relatively few studies have considered scanning micro-arc oxidation (SMAO). In the present work, an experimental study was performed using stationary and moving electrodes to investigate coating development in SMAO and discern the effect of key process parameters. Examination of oxide deposits made on A356 aluminum show that coating thickness and growth rate are inversely related to inter-electrode spacing and travel speed. An evaluation of SMAO deposits made by stationary and moving nozzles revealed that coating thickness profiles follow a Gaussian distribution due to the electrolyte flow field in the impingement zone. Hardness surveys and scanning electron microscope analysis of SMAO coatings revealed that micro-hardness distributions and cross-sectional morphology are similar to MAO for a stationary nozzle but that a denser outer layer develops when a moving nozzle is used. This is attributed to a high density of discharge occurring in micropores of the oxide film and remelting which results from the moving electrolyte column. Analysis of voltage-current characteristic curves shows that the resistance of the electrolyte column is essentially linear over the range considered and results indicate that it can be modeled as a variable length resistor. While further testing is needed, results confirm that SMAO is suitable for coating large, planar parts and for repairing worn surfaces.

  12. Evaluation of Photocatalytic Active Coatings on Sintered Glass Tubes by Methylene Blue

    Directory of Open Access Journals (Sweden)

    Colin Awungacha Lekelefac

    2013-01-01

    Full Text Available A comparative study between ten different photocatalytic active coatings was done. The effectiveness and photocatalytic activity of the coatings were studied by degradation experiments of methylene blue (MB dye under UV light illumination. The reactor design consisting of sintered glass packed in a borosilicate tube placed between two planar dielectric barrier discharge lamps (Osram Planon is reported for the first time. The coatings consisted of either titania, silica, or zinc on sintered borosilicate glass. The advantage of sol-gel in catalyst preparation was exploited to combine catalyst to act as cocatalyst. TiO2-P25 widely applied in suspension systems was effectively immobilized on sintered glass support with the aid of tetraethylorthosilicate (TEOS solution which acted as support material. Results indicated that TiO2-P25+SiO2, TiO2-P25+SiO2+Pt, and TiOSO4_30,6wt% films showed highest degradation rates close to 100% after 90 min illumination with degradation rates exceeding 50% after 30 minutes. TTIP+Pt showed lowest degradation rate.

  13. Biological activity evaluation of magnesium fluoride coated Mg-Zn-Zr alloy in vivo.

    Science.gov (United States)

    Jiang, Hongfeng; Wang, Jingbo; Chen, Minfang; Liu, Debao

    2017-06-01

    To explore the biodegradable characteristics and biological properties, which could promote new bone formation, of MgF2 coated magnesium alloy (Mg-3wt%Zn-0.5wt%Zr) in rabbits. Magnesium alloy with MgF2 coating was made and the MgF2/Mg-Zn-Zr was implanted in the femoral condyle of rabbits. Twelve healthy adult Japanese white rabbits in weight of 2.8-3.2kg were averagely divided into A(Mg-Zn-Zr) group and B(MgF2/MgZn-Zr) group. Indexes such as microstructural evolution, SEM scan, X-ray, Micro-CT and mechanical properties were observed and detected at 1th day, 2th, 4th, 8th, 12th, 24th week after implantation. Low-density regions occurred around the cancellous bone, and the regions gradually expanded during the 12weeks after implantation. The implant was gradually absorbed from 12 to 24weeks. The density of surrounding cancellous bone increased compared with the 12th week data. The degradation rate of B group was lower than that of A group (Pmagnesium ions. The biological properties of the coating itself presented good biocompatibility and bioactivity. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. Computational Evaluation of Amorphous Carbon Coating for Durable Silicon Anodes for Lithium-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Jeongwoon Hwang

    2015-10-01

    Full Text Available We investigate the structural, mechanical, and electronic properties of graphite-like amorphous carbon coating on bulky silicon to examine whether it can improve the durability of the silicon anodes of lithium-ion batteries using molecular dynamics simulations and ab-initio electronic structure calculations. Structural models of carbon coating are constructed using molecular dynamics simulations of atomic carbon deposition with low incident energies (1–16 eV. As the incident energy decreases, the ratio of sp2 carbons increases, that of sp3 decreases, and the carbon films become more porous. The films prepared with very low incident energy contain lithium-ion conducting channels. Also, those films are electrically conductive to supplement the poor conductivity of silicon and can restore their structure after large deformation to accommodate the volume change during the operations. As a result of this study, we suggest that graphite-like porous carbon coating on silicon will extend the lifetime of the silicon anodes of lithium-ion batteries.

  15. An evaluation of the adhesion of solid oral dosage form coatings to the oesophagus.

    Science.gov (United States)

    Smart, John D; Dunkley, Sian; Tsibouklis, John; Young, Simon

    2015-12-30

    There is a requirement for the development of oral dosage forms that are adhesive and allow extended oesophageal residence time for localised therapies, or are non-adhesive for ease of swallowing. This study provides an initial assessment of the in vitro oesophageal retention characteristics of several widely utilised pharmaceutical coating materials. To this end, a previously described apparatus has been used to measure the force required to pull a coated disc-shaped model tablet across a section of excised oesophageal tissue. Of the materials tested, the well-studied mucoadhesive polymer sodium alginate was found to be associated with significant oesophageal adhesion properties that was capable of 'self-repairing'. Hydroxypropylmethylcellulose exhibited less pronounced bioadhesive behaviour and blending this with plasticiser or with low molecular weight polymers and surfactants did not significantly affect this. Low molecular weight water soluble polymers, were found to behave similarly to the uncoated glass control disc. Polysorbates exhibited bioadhesion behaviour that was majorly influenced by the nature of the surfactant. The insoluble polymer ethylcellulose, and the relatively lipophilic surfactant sorbitan monooleate were seen to move more readily than the uncoated disc, suggesting that these may have a role as 'easy-to-swallow' coatings. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Evaluation of Humic Acid and Tannic Acid Fouling in Graphene Oxide-Coated Ultrafiltration Membranes.

    Science.gov (United States)

    Chu, Kyoung Hoon; Huang, Yi; Yu, Miao; Her, Namguk; Flora, Joseph R V; Park, Chang Min; Kim, Suhan; Cho, Jaeweon; Yoon, Yeomin

    2016-08-31

    Three commercially available ultrafiltration (UF) membranes (poly(ether sulfone), PES) that have nominal molecular weight cut-offs (5, 10, and 30 kDa) were coated with graphene oxide (GO) nanosheets. Field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy, confocal laser scanning microscopy, water contact angle measurements, and X-ray photoelectron spectroscopy were employed to determine the changed physicochemical properties of the membranes after GO coating. The water permeability and single-solute rejection of GO-coated (GOC) membranes for humic acid (HA) molecules were significantly higher by approximately 15% and 55%, respectively, compared to those of pristine UF membranes. However, the GOc membranes for single-solute tannic acid (TA) rejection showed similar trends of higher flux decline versus pristine PES membranes, because the relatively smaller TA molecules were readily adsorbed onto the membrane pores. When the mixed-solute of HA and TA rejection tests were performed, in particular, the adsorbed small TA molecules resulted in irreversible membrane fouling due to cake formation and membrane pore blocking on the membrane surface for the HA molecules. Although both membranes showed significantly higher flux declines for small molecules rejection, the GOc membranes showed better performance than the pristine UF membranes in terms of the rejection of various mixed-solute molecules, due to higher membrane recovery and antifouling capabilities.

  17. Experimental and computer thermodynamics evaluations of an Al-Si-Coating on a quenchable steel

    Energy Technology Data Exchange (ETDEWEB)

    Trindade, Vicente Braz, E-mail: vicentebraz@yahoo.com.b [Universidade Federal de Ouro Preto (UFOP), Ouro Preto, MG (Brazil). Escola de Minas. Departamento de Engenharia Metalurgica e de Materiais; Christ, Hans-Juergen, E-mail: christ@ifwt.mb.uni-siegen.de [University of Siegen (Germany)

    2017-01-15

    High-strength steels are commonly used in the automobile industry in order to reduce the weight of the vehicles. However, a technical difficulty appears due to the need of hot stamping of the components, which leads to oxidation. Therefore, the application of a coating on the substrate to avoid high-temperature oxidation is used. In this work, experimental analysis and computer thermodynamic calculation were used to describe the phase transformations within an Al-Si coating on a quenchable high strength steel. The Al-Si coating was deposited by hot dipping and its characterization was done using SEM and XRD techniques. Computer thermodynamics calculations were done using the commercial software FactSage using the Calphad methodology. It demonstrated a good relationship between the experimental results and the computer calculations of phase stabilities for the as-deposited condition and after diffusion experiment at 920 deg C for 7 minutes, which simulates the thermal cycle of hot stamping of the quenchable steel used. (author)

  18. Characterization of flame-sprayed and plasma-sprayed pure metallic and alloyed coatings

    Energy Technology Data Exchange (ETDEWEB)

    Iordanova, I. [Sofia Univ. (Bulgaria). Dept. of Solid State Phys.; Forcey, K.S. [CEC, Joint Research Centre, Ispra Site, 21020 Ispra (Vatican City State, Holy See) (Italy); Gergov, B. [Sofia Univ. (Bulgaria). Dept. of Solid State Phys.; Bojinov, V. [Department of Inorganic Chemical Technology, The University of Sofia, Blvd. J. Bouchier 1, 1126 Sofia (Bulgaria)

    1995-05-01

    The composition, structure and properties of thermally sprayed coatings were investigated by a number of methods, including X-ray diffraction, X-ray spectroscopy and scanning electron microscopy. The Vickers hardness and porosity were also investigated. The coatings were plasma-sprayed pure molybdenum, and flame-sprayed copper and nickel alloys. It was found that the alloyed coatings had a different chemical composition than the powders they had been produced from. In addition, all the coatings exhibited a fibre texture which complicated the X-ray method for estimation of residual stresses. However, for the pure molybdenum coating, it was possible to evaluate this parameter, taking into account the effects of the measured porosity and crystallographical anisotropy on the Young`s modulus and Poisson`s ratio. ((orig.))

  19. Application of Taguchi Method to the Optimization of a-C:H Coatings Deposited Using Ion Beam Assisted Physical Vapor Deposition

    Directory of Open Access Journals (Sweden)

    W. H. Kao

    2015-02-01

    Full Text Available The Taguchi design method is used to optimize the adhesion, hardness, and wear resistance properties of a-C:H coatings deposited on AISI M2 steel substrates using the ion beam assisted physical vapor deposition method. The adhesion strength of the coatings is evaluated by means of scratch tests, while the hardness is measured using a nanoindentation tester. Finally, the wear resistance is evaluated by performing cyclic ball-on-disc wear tests. The Taguchi experimental results show that the optimal deposition parameters are as follows: a substrate bias voltage of 90 V, an ion beam voltage of 1 kV, an acetylene flow rate of 21 sccm, and a working distance of 7 cm. Given these optimal processing conditions, the a-C:H coating has a critical load of 99.8 N, a hardness of 25.5 GPa, and a wear rate of 0.4 × 10−6 mm3/Nm.

  20. Evaluation of coated columbian alloy heat shields for space shuttle thermal protection system application. Volume 1: Phase 1 - Environmental criteria and material characterization, October 1970 - March 1972

    Science.gov (United States)

    Black, W. E.

    1972-01-01

    The studies presented are directed toward establishing criteria for a niobium alloy thermal protection system for the space shuttle. Evaluation of three niobium alloys and two silicon coatings for heat shield configurations culminated in the selection of two coating/substrate combinations for environmental criteria and material characterization tests. Specimens were exposed to boost and reentry temperatures, pressure, and loads simulating a space shuttle orbiter flight profile.

  1. Delamination evaluation of thermal barrier coating on turbine blade owing to isothermal degradation using ultrasonic C-scan image

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Girl; Kim, Hak Joon; Song, Sung Jin; Seok, Chang Sung [Dept. of Mechanical Engineering, Sungkyunkwan University, Suwon (Korea, Republic of)

    2016-10-15

    Thermal barrier coating (TBC) is an essential element consisting of a super-alloy base and ceramic coating designed to achieve long operational time under a high temperature and pressure environment. However, the top coat of TBC can be delaminated at certain temperatures with long operation time. As the delamination of TBC is directly related to the blade damage, the coupling status of the TBC should be assured for reliable operation. Conventional studies of nondestructive evaluation have been made for detecting generation of thermally grown oxide (TGO) or qualitatively evaluating delamination in TBC. In this study, the ultrasonic C-scan method was developed to obtain the damage map inside TBC by estimating the delamination in a quantitative way. All specimens were isothermally degraded at 1,100°C with different time, having different partial delamination area. To detect partial delamination in TBC, the C-scan was performed by a single transducer using pulse-echo method with normal incidence. Partial delamination coefficients of 1 mm to 6 mm were derived by the proportion of the surface reflection signal and flaw signal which were theoretical signals using Rogers-Van Buren and Kim's equations. Using the partial delamination coefficients, the partial delamination maps were obtained. Regardless of the partial delamination coefficient, partial delamination area was increased when degradation time was increased in TBC. In addition, a decrease in partial delamination area in each TBC specimen was observed when the partial delamination coefficient was increased. From the portion of the partial delamination maps, the criterion for delamination was derived.

  2. Clinical evaluation of a bioactive beta-glucan gel in the treatment of 'hard-to-heal' wounds.

    Science.gov (United States)

    King, B; Barrett, S; Cutting, K F

    2017-02-02

    The aim of this evaluation is to assess the effects of a wound healing gel in a wounds of different aetiologies. Data was recorded on the wound surface area, tissue type, and patient level of wound pain at baseline (0) and at weeks 1, 2, 3, 4, and 8. Of the total 39 patients enrolled in the study, 26 patients who complied with the protocol criteria completed the minimum four-week study period. During the 12-week evaluation period, seven of the 26 wounds fully healed and an additional eight wounds showed a reduction in size of more than 50 %. Of the remaining 11, five wounds showed moderate healing progression and six wounds did not respond to treatment. Following the 12 week evaluation time point clinicians reported that a further three wounds healed-a 38 % healing rate. The results give promise that this advanced gel, containing a macrophage activating substance, can be a tool in re-activating healing in stalled wounds where standard of care is no longer giving the desired healing progression.

  3. Preparation and in vitro Evaluation of Ethylcellulose Coated Egg Albumin Microspheres of Diltiazem Hydrochloride.

    Science.gov (United States)

    Shailesh, Tp; Vipul, Pd; Girishbhai, Jk; Manish, Cj

    2010-01-01

    The aim of the present investigation was to develop sustained release ethylcellulose-coated egg albumin microspheres of diltiazem hydrochloride (DH) to improve patient compliance. The microspheres were prepared by the w/o emulsion thermal cross-linking method using different proportion of the polymer to drug ratio (1.0:1.0, 1.0:1.5 and 1.0:2.0). A 3(2) full factorial design was employed to optimize two independent variables, polymer to drug ratio (X(1)) and surfactant concentration (X(2)) on dependent variables, namely % drug loading, % drug release in 60 min (Y(60)) and the time required for 80 % drug release (t(80)) were selected as dependable variable. Optimized formulation was compared to its sustained release tablet available in market. The polymer to drug ratio was optimized to 1:1 at which a high drug entrapment efficiency 79.20% ± 0.7% and the geometric mean diameter 47.30 ± 1.5 mm were found. All batches showed a biphasic release pattern; initial burst release effect (55% DH in 1 h) and then were released completely within 6 h. In situ coating of optimized egg albumin DH microspheres using 7.5% ethylcellulose significantly reduced the burst effect and provided a slow release of DH for 8-10 h. Finally, it was concluded that ethylcellulose-coated egg albumin DH microspheres is suitable for oral SR devices in the treatment of angina pectoris, cardiac arrhythmias, and hypertension due to their size and release profile.

  4. Evaluation of the content of TiO2 nanoparticles in the coatings of chewing gums.

    Science.gov (United States)

    Dudefoi, William; Terrisse, Hélène; Popa, Aurelian Florin; Gautron, Eric; Humbert, Bernard; Ropers, Marie-Hélène

    2018-02-01

    Titanium dioxide is a metal oxide used as a white pigment in many food categories, including confectionery. Due to differences in the mass fraction of nanoparticles contained in TiO2, the estimated intakes of TiO2 nanoparticles differ by a factor of 10 in the literature. To resolve this problem, a better estimation of the mass of nanoparticles present in food products is needed. In this study, we focused our efforts on chewing gum, which is one of the food products contributing most to the intake of TiO2. The coatings of four kinds of chewing gum, where the presence of TiO2 was confirmed by Raman spectroscopy, were extracted in aqueous phases. The extracts were analysed by transmission electron microscopy (TEM), X-ray diffraction, Fourier Transform Raman spectroscopy, and inductively coupled plasma atomic emission spectroscopy (ICP-AES) to establish their chemical composition, crystallinity and size distribution. The coatings of the four chewing gums differ chemically from each other, and more specifically the amount of TiO2 varies from one coating to another. TiO2 particles constitute the entire coating of some chewing gums, whereas for others, TiO2 particles are embedded in an organic matrix and/or mixed with minerals like calcium carbonate, talc, or magnesium silicate. We found 1.1 ± 0.3 to 17.3 ± 0.9 mg TiO2 particles per piece of chewing gum, with a mean diameter of 135 ± 42 nm. TiO2 nanoparticles account for 19 ± 4% of all particles, which represents a mass fraction of 4.2 ± 0.1% on average. The intake of nanoparticles is thus highly dependent on the kind of chewing gum, with an estimated range extending from 0.04 ± 0.01 to 0.81 ± 0.04 mg of nano-TiO2 per piece of chewing gum. These data should serve to refine the exposure scenario.

  5. Combustion Products Evaluation from Hull Insulation Materials Coated with Fire Retardant Paints.

    Science.gov (United States)

    1980-09-08

    Bureau of Standards, Report No. NBSIR 78-1584 of May 1979. 2. P.A. Tatem, "Production of Gaseous Combustion Products from Insulating Foam ( Armaflex -FR...Letter Report 6180-102:PAT:bh of 15 May 1975. 6. P.A. Tatem, I.T. Cheng and F.W. Williams, "Toxic Product Evolution from Armaflex -FR and Armaflex -FR...I.T. Cheng and F.W. Williams, "Toxic Product Evolution from Armaflex -FR Coated with Fire Retardant Paints, Part I; forwarding of information on," NRL

  6. Evaluation of 3D-Printed Polycaprolactone Scaffolds Coated with Freeze-Dried Platelet-Rich Plasma for Bone Regeneration

    Directory of Open Access Journals (Sweden)

    Junda Li

    2017-07-01

    Full Text Available Three-dimensional printing is one of the most promising techniques for the manufacturing of scaffolds for bone tissue engineering. However, a pure scaffold is limited by its biological properties. Platelet-rich plasma (PRP has been shown to have the potential to improve the osteogenic effect. In this study, we improved the biological properties of scaffolds by coating 3D-printed polycaprolactone (PCL scaffolds with freeze-dried and traditionally prepared PRP, and we evaluated these scaffolds through in vitro and in vivo experiments. In vitro, we evaluated the interaction between dental pulp stem cells (DPSCs and the scaffolds by measuring cell proliferation, alkaline phosphatase (ALP activity, and osteogenic differentiation. The results showed that freeze-dried PRP significantly enhanced ALP activity and the mRNA expression levels of osteogenic genes (ALP, RUNX2 (runt-related gene-2, OCN (osteocalcin, OPN (osteopontin of DPSCs (p < 0.05. In vivo, 5 mm calvarial defects were created, and the PRP-PCL scaffolds were implanted. The data showed that compared with traditional PRP-PCL scaffolds or bare PCL scaffolds, the freeze-dried PRP-PCL scaffolds induced significantly greater bone formation (p < 0.05. All these data suggest that coating 3D-printed PCL scaffolds with freeze-dried PRP can promote greater osteogenic differentiation of DPSCs and induce more bone formation, which may have great potential in future clinical applications.

  7. Coating solid dispersions on microneedles via a molten dip coating method: development and in vitro evaluation for transdermal delivery of a water insoluble drug

    Science.gov (United States)

    Ma, Yunzhe; Gill, Harvinder S.

    2014-01-01

    This study demonstrates for the first time the ability to coat solid dispersions on microneedles as a means to deliver water-insoluble drugs through the skin. Polyethylene glycol (PEG) was selected as the hydrophilic matrix, and lidocaine base was selected as the model hydrophobic drug to create the solid dispersion. First, thermal characterization and viscosity measurements of the PEG-lidocaine mixture at different mass fractions were performed. The results show that lidocaine can remain stable at temperatures up to ~130 °C, and that viscosity of the PEG-lidocaine molten solution increases as the mass fraction of lidocaine decreases. Differential scanning calorimetry demonstrated that at lidocaine mass fraction less than or equal to 50%, lidocaine is well dispersed in the PEG-lidocaine mixture. Uniform coatings were obtained on microneedle surfaces. In vitro dissolution studies in porcine skin showed that microneedles coated with PEG-lidocaine dispersions resulted in significantly higher delivery of lidocaine in just 3 min compared to 1 h topical application of 0.15 g EMLA®, a commercial lidocaine-prilocaine cream. In conclusion, the molten coating process we introduce here offers a practical approach to coat water-insoluble drugs on microneedles for transdermal delivery. PMID:25213295

  8. The use of the Rietveld method as an evaluation tool in the stages of production of nanostructured hard metal

    Energy Technology Data Exchange (ETDEWEB)

    Batista, A.C.; Perpetuo, G.J., E-mail: adrianocorrea77@gmail.com [Rede Tematica de Engenharia de Materiais (REDEMAT), Ouro Preto, Minas Gerais (Brazil); Oliveira, H.C.P. de [Instituto Superior Tecnico (IST), Lisboa (Portugal). Departamento de Materiais; Silva, T.R.G. da [Universidade Federal de Ouro Preto (UFOP), Ouro Preto, MG (Brazil). Departamento de Fisica

    2014-07-01

    The processing of the composite WC-10% Co, with nanometric grain size was analyzed aiming at identifying changes undergone by the material during mixing and compaction steps. Use the X-ray diffraction and the Rietveld method to obtain accurate data on the behavior of powders before these steps. This paper describes the use of the Rietveld method as an evaluation tool to obtain information about the behavior of powders of WC and Co steps during mixing and compaction prior to sintering of the composite. (author)

  9. Thermodynamic hardness and the maximum hardness principle

    Science.gov (United States)

    Franco-Pérez, Marco; Gázquez, José L.; Ayers, Paul W.; Vela, Alberto

    2017-08-01

    An alternative definition of hardness (called the thermodynamic hardness) within the grand canonical ensemble formalism is proposed in terms of the partial derivative of the electronic chemical potential with respect to the thermodynamic chemical potential of the reservoir, keeping the temperature and the external potential constant. This temperature dependent definition may be interpreted as a measure of the propensity of a system to go through a charge transfer process when it interacts with other species, and thus it keeps the philosophy of the original definition. When the derivative is expressed in terms of the three-state ensemble model, in the regime of low temperatures and up to temperatures of chemical interest, one finds that for zero fractional charge, the thermodynamic hardness is proportional to T-1(I -A ) , where I is the first ionization potential, A is the electron affinity, and T is the temperature. However, the thermodynamic hardness is nearly zero when the fractional charge is different from zero. Thus, through the present definition, one avoids the presence of the Dirac delta function. We show that the chemical hardness defined in this way provides meaningful and discernible information about the hardness properties of a chemical species exhibiting integer or a fractional average number of electrons, and this analysis allowed us to establish a link between the maximum possible value of the hardness here defined, with the minimum softness principle, showing that both principles are related to minimum fractional charge and maximum stability conditions.

  10. Synthesis, Characterization, and Toxicity Evaluation of Dextran-Coated Iron Oxide Nanoparticles

    Directory of Open Access Journals (Sweden)

    Mihaela Balas

    2017-02-01

    Full Text Available We report the synthesis of dextran-coated iron oxide magnetic nanoparticles (DIO-NPs with spherical shape and uniform size distribution as well as their accumulation and toxic effects on Jurkat cells up to 72 h. The characterization of dextran-coated maghemite nanoparticles was done by X-ray diffraction and dynamic light scattering analyses, transmission electron microscopy imaging, attenuated total reflectance Fourier transform infrared (ATR-FTIR spectroscopy, magnetic hysteresis, and relaxometry measurements. The quantification of DIO-NPs intracellular uptake showed a progressive accumulation of iron as a function of time and dose accompanied by additional lysosome formation and an increasing darkening exhibited by a magnetic resonance imaging (MRI scanner. The cytotoxicity assays revealed a decrease of cell viability and a loss of membrane integrity in a time- and dose-dependent manner. Exposure to DIO-NPs determined an increase in reactive oxygen species level up to 72 h. In the first two days of exposure, the level of reduced glutathione decreased and the amount of malondyaldehyde increased, but at the end of the experiment, their concentrations returned to control values. These nanoparticles could be used as contrast agents for MRI but several parameters concerning their interaction with the cells should be taken into consideration for a safe utilization.

  11. Experimental evaluation of coated carbide insert on alloy of steel materials during high speed turning process

    Directory of Open Access Journals (Sweden)

    S. A. Lawal

    2017-06-01

    Full Text Available The present study investigated the effect of coated carbide turning inserts on the surface roughness of AISI 304L austenitic stainless steel, AISI 316L austenitic stainless steel and AISI 1020 low carbon steel workpiece materials. The three steel grade materials were dry-turned using aluminium oxide (Al2O3 duratomic coated inserts at cutting speeds ranging from 1500 – 2000 rpm (229 – 314 m/min, feed rates of 0.25 – 0.75 mm/rev and depth of cut kept constant at 0.5 mm. Surface roughness values at different cutting conditions were measured and analysed. Chips formed at different cutting parameters were collected, classified according to ISO 3685 standards for chip classification and their surface morphology were analysed using optical microscopy. It was observed that feed rate had the greatest influence on surface roughness for the three workpiece materials. Surface finish deteriorated as feed rate increased. The chips formed were generally of the continuous type with built-up-edges.

  12. Evaluation of antimicrobial efficacy of nano coated silver-titania metallic plates against selective pathogens

    Directory of Open Access Journals (Sweden)

    Mohamad, S.M.

    2012-01-01

    Full Text Available Aim: Nanotechnology is an increasingly growing field with its current application in Science and Technology for the purpose of manufacture of novel materials at the nanoscale level. Silver-Titania nanoparticles (AgTiO2-NPs have been known to have inhibitory and bactericidal effects.Methodology and Results: In the present study, stable silver-titania nanoparticles coated metallic blocks were prepared for testing their efficacy against selected bacterial pathogens like Escherichia coli and Staphylococcus aureus. In the experimental part, the bacterial pathogens were inoculated on silver-titania nanoparticle coated blocks and the treatment was carried out in „0‟ time and „24‟ h interval and were enumerated.Conclusion, significance and impact of study:The results were compared with the control (uncoated metallic blocks and analyzed by using Japanese Industrial Standard (JIS Z2801:2000 method. From this study, it was concluded that silver-titania nanoparticles has inhibitory effect on bacterial pathogen tested.

  13. On the evaluation of stability of rare earth oxides as face coats for investment casting of titanium

    Science.gov (United States)

    Saha, R. L.; Nandy, T. K.; Misra, R. D. K.; Jacob, K. T.

    1990-06-01

    Attempts have been made to evaluate the thermal stability of rare earth oxide face coats against liquid titanium. Determination of microhardness profiles and concentration profiles of oxygen and metallic constituents of oxide in investment cast titanium rods has allowed grActation of relative stability of rare earth oxides. The relative stability of evaluated oxides in the order of increasing stability follows the sequence CeO2 — ZrO2 — Gd2O3 — didymium oxide — Sm2O3 —Nd2O3 — Y2O3. The grading does not follow the free energy data of the formation of these oxides. A better correlation with the experimental observations is obtained when the solubility of the metallic species in titanium is also taken into consideration.

  14. Federal Highway Administration 100-year coating study.

    Science.gov (United States)

    2012-11-01

    The Federal Highway Administration 100-Year Coating Study was initiated in August 2009 to search for durable : coating systems at a reasonable cost. The objective of the study was to identify and evaluate coating materials that can : provide 100 year...

  15. Comparative evaluation of sutures coated with triclosan and chlorhexidine for oral biofilm inhibition potential and antimicrobial activity against periodontal pathogens: An in vitro study

    Directory of Open Access Journals (Sweden)

    Kunal Sunder Sethi

    2016-01-01

    Full Text Available Background: Surgical site plaque accumulation is one of the challenging problems leading to unfavorable healing. The antibacterial sutures can be used to reduce or inhibit plaque formation. Presently there is no study comparing efficacy of sutures coated with triclosan and chlorhexidine in terms of oral biofilm inhibition and antimicrobial property against periodontal pathogens. Aim: The aim of present study was to evaluate the antibacterial efficacy and oral biofilm inhibition around chlorhexidine and triclosan coated polyglactin sutures in comparison to uncoated sutures. Materials and Method: Equal segments of chlorhexidine and triclosan coated polyglactin sutures (3-0 were incubated at 370°C in saliva collected from 10 chronic periodontitis patients for 7 days. Plain uncoated suture served as control. Biofilm formation was analyzed with Confocal Laser-Scanning Microscopy (CLSM and Scanning Electron Microscopy (SEM. Quantitative assessment was done using Colony Forming Units (CFU/mL.The antibacterial efficacy of the sutures was tested against specific periodontal pathogens (S.mutans, F.nucleatum, A.actinomycetomcomitans, P.intermedia, P.gingivalis using agar diffusion method. CLSM and SEM were not subjected to statistical analysis. ANOVA test was used for colony forming units and agar diffusion test. (P < 0.05 Results: CLSM and SEM showed substantial biofilm inhibition around chlorhexidine-coated sutures followed by triclosan-coated when compared to plain uncoated suture. The antibacterial coated sutures showed statistically significant difference in CFUs/ml and zone of inhibition compared to plain uncoated sutures. Among coated sutures, chlorhexidine-coated sutures showed better results. Conclusion: The antibacterial coated sutures have a promising potential in preventing the colonization of periodontal pathogens around it thereby inhibiting biofilm formation.

  16. Comparative evaluation of sutures coated with triclosan and chlorhexidine for oral biofilm inhibition potential and antimicrobial activity against periodontal pathogens: An in vitro study.

    Science.gov (United States)

    Sethi, Kunal Sunder; Karde, Prerna Ashok; Joshi, Chaitanya Pradeep

    2016-01-01

    Surgical site plaque accumulation is one of the challenging problems leading to unfavorable healing. The antibacterial sutures can be used to reduce or inhibit plaque formation. Presently there is no study comparing efficacy of sutures coated with triclosan and chlorhexidine in terms of oral biofilm inhibition and antimicrobial property against periodontal pathogens. The aim of present study was to evaluate the antibacterial efficacy and oral biofilm inhibition around chlorhexidine and triclosan coated polyglactin sutures in comparison to uncoated sutures. Equal segments of chlorhexidine and triclosan coated polyglactin sutures (3-0) were incubated at 370°C in saliva collected from 10 chronic periodontitis patients for 7 days. Plain uncoated suture served as control. Biofilm formation was analyzed with Confocal Laser-Scanning Microscopy (CLSM) and Scanning Electron Microscopy (SEM). Quantitative assessment was done using Colony Forming Units (CFU/mL).The antibacterial efficacy of the sutures was tested against specific periodontal pathogens (S.mutans, F.nucleatum, A.actinomycetomcomitans, P.intermedia, P.gingivalis) using agar diffusion method. CLSM and SEM were not subjected to statistical analysis. ANOVA test was used for colony forming units and agar diffusion test. (P chlorhexidine-coated sutures followed by triclosan-coated when compared to plain uncoated suture. The antibacterial coated sutures showed statistically significant difference in CFUs/ml and zone of inhibition compared to plain uncoated sutures. Among coated sutures, chlorhexidine-coated sutures showed better results. The antibacterial coated sutures have a promising potential in preventing the colonization of periodontal pathogens around it thereby inhibiting biofilm formation.

  17. Evaluation of tetraethoxysilane (TEOS) sol–gel coatings, modified with green synthesized zinc oxide nanoparticles for combating microfouling

    Energy Technology Data Exchange (ETDEWEB)

    Krupa, A. Nithya Deva; Vimala, R., E-mail: vimala.r@vit.ac.in

    2016-04-01

    Green synthesis of zinc oxide nanoparticles (ZnO-NPs) is gaining importance as an eco-friendly alternative to conventional methods due to its enormous applications. The present work reports the synthesis of ZnO-NPs using the endosperm of Cocos nucifera (coconut water) and the bio-molecules responsible for nanoparticle formation have been identified. The synthesized nanoparticles were characterized using UV–Visible spectroscopy (UV–Vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Transmission Electron Microscopy (TEM) and Zeta potential measurement. The results obtained reveal that the synthesized nanoparticles are moderately stable with the size ranging from 20 to 80 nm. The bactericidal effect of the nanoparticles was proved by well diffusion assay and determination of minimum inhibitory concentration (MIC) against marine biofilm forming bacteria. Further the green synthesized ZnO-NPs were doped with TEOS sol–gels (TESGs) in order to assess their antimicrofouling capability. Different volumes of liquid sol–gels were coated on to 96-well microtitre plate and cured under various conditions. The optimum curing conditions were found to be temperature 60 °C, time 72 h and volume 200 μl. Antiadhesion test of the undoped (SG) and ZnO-NP doped TEOS sol–gel (ZNSG) coatings were evaluated using marine biofilm forming bacteria. ZNSG coatings exhibited highest biofilm inhibition (89.2%) represented by lowest OD value against Pseudomonasotitidis strain NV1. - Highlights: • The study reports low cost, and simple procedure for the synthesis of ZnO-NPs using coconut water. • XRD result shows the high crystalline nature of the synthesized ZnO-NPs. • TEM and zeta potential distribution confirms the nanostructure, stability of the synthesized ZnO-NPs. • ZnO-NPs doped with TEOS sol¬-gels (TESGs) exhibited excellent antimicrofouling activity.

  18. Preparation, Characterization and in vivo Evaluation of Simple Monolithic Ethylcellulose-coated Pellets Containing Topiramate with Biphasic Release Characteristics.

    Science.gov (United States)

    Gong, Wei; Wang, Yuli; Shao, Shuai; Xie, Si; Shan, Li; Yang, Meiyan; Gao, Chunsheng; Zhong, Wu

    2016-01-01

    In our previous study, polyvinylpyrrolidone (PVP) was used both as a binder and a pore-former to prepare ethylcellulose (EC)-coated pellets to deliver topiramate (TPM) for a controlled release profile. The objective of this work was to further optimize the formulation and evaluate the in vivo profiles of TPM sustained-release pellets. Similar to the previous formulation with no binder, the in vitro drug release of TPM sustained-release pellets with 50% PVP binder in drug layer was sensitive to pore-former PVP level ranged from 27.0% to 29.0%. The higher the level of PVP was, the quicker release rate in vitro was. Moreover, when the proportion of poreformer PVP decreased, the Cmax decreased, and the tmax and mean residence time of TPM coated pellets were both prolonged. The in vitro release profile of optimal formulation showed biphasic release characteristics similar to reference formulation Trokendi XR(®), i.e., involving immediate release of TPM in initial release stage followed by a sustained release up to 24 h. Moreover, the impact of the pH of release medium on the drug release rate of TPM sustained-release pellets was not significant. The release mechanism of TPM from the sustained-release pellets might be the interaction of diffusion (coating-film) and corrosion (drug layer). The in vivo pharmacokinetics results showed the TPM sustained-release pellets had the similar in vivo pattern compared with Trokendi XR(®). These studies provide valuable basis for further development of TPM sustained-release pellets.

  19. Multi-functional hybrid coatings containing silica nanoparticles and anti-corrosive acrylate monomer for scratch and corrosion resistance.

    Science.gov (United States)

    Seo, Ji Yeon; Han, Mijeong

    2011-01-14

    Multi-functional hybrid coatings having both anti-corrosion and scratch resistance were prepared from modified silica nanoparticles and functional acrylates. To improve the dispersion properties of silica nanoparticles in the organic/inorganic hybrid coatings, the surface of the nanoparticles was modified with γ-methacryloxypropyltrimethoxysilane. The coating solution could be prepared by mixing modified silica nanoparticles, tetrasiloxane acrylate, di-acrylate monomer containing an anti-corrosion functional group, acrylic acid, and an initiator in a solvent. The mixture was then dip-coated on iron substrates and finally polymerized by ultraviolet (UV) irradiation. Corrosion and scratch resistance of the coated iron was evaluated by electrochemical impedance spectroscopy (EIS) and a pencil hardness test, respectively. From the EIS results, the coatings with tetrasiloxane acrylate and di-acrylate did not show any decrease in impedance or phase angle, even after 50 days' exposure to 0.1 M NaCl electrolyte, whereas the conventional acrylate coatings started to fail after only 24 h. A hybrid coating containing the amine-quinone functional group exhibited excellent corrosion protection properties with 4-5H pencil hardness.

  20. Effect of deposition current on microstructure and properties of CoCrWC alloy PTA coatings

    Directory of Open Access Journals (Sweden)

    R. M. G. Paes

    2014-09-01

    Full Text Available Cobalt-Based alloys are largely applied to the surface of components as welded coatings. Carbides reinforced CoCrWC system is used to extend the service life under harsh environments involving wear and corrosion in different media. This work aims to evaluate the effect of deposition current on the microstructure and properties of PTA coatings. So, CoCrWC alloy (Stellite #6 was processed on AISI316L stainless steel plates with the following main arc current: 100, 120, 150, 180 and 200A. So, different interaction with the substrate must be expected and its effect on coatings features was evaluated. The geometry of single track coatings, dilution, formed phases and phase volume fraction was assessed by laser Confocal, scanning electron microscopy and X-ray diffraction analysis. Vickers hardness and wear tests were carried out to correlate microstructure to properties of coatings. Coatings showed microstructure composed by hypoeutectic dendrites of Cobalt solid solution and interdendrictic carbides. Dilution increased with deposition current from 11,8 e 56,5% which reduced the carbides fraction and increased the Cobalt solid solution areas, resulting in hardness decrease from 500 to 310HV0,5. Higher deposition current induced mass loss rate increase on pin-on-disc sliding wear tests, arising 44,38% increment on wear coefficient, as a consequence of the lower carbides fraction and solid solution alloying and refinement degree of the microstructure.

  1. Evaluation of the hard and soft tissue changes after maxillary advancement with rigid external distractor in unilateral cleft lip and palate induced maxillary hypoplasia.

    Science.gov (United States)

    Sahoo, N K; Jayan, B; Roy, I D; Desai, Ajay

    2015-12-01

    Midfacial growth retardation in cleft lip and palate (CLP) cases, is seen in all the three dimensions. Conventionally these cases are managed by orthographic surgery which has a high rate of relapse. The application of the distraction osteogenesis (DO) has revolutionized the management protocol. The aim of the study was to evaluate the efficacy of rigid external distractor (RED) in management of cleft induced maxillary hypoplasia. Ten cases of unilateral CLP between 11 and 20 years of age having gross midfacial deficiency and those who have undergone presurgical orthodontic treatment were included in the study. The cases were operated for Le Fort 1 osteotomy and application of RED. DO was carried out through transnasal traction wires. Clinico-radiological evaluation of presurgical and 1, 6 and 12 months post distraction parameters were statistically analysed by application of paired 't'-test. There were 4 males and 6 females with a mean age of 15.1 years. The mean distraction carried out was 14.95 mm. There was a significant improvement in all the hard and soft tissue parameters except SNB. Facial profile improvement and stable occlusion was achieved in all the cases. Midfacial DO using RED is a versatile procedure where the maxilla can be moved in multiple planes to achieve a functional, aesthetic and occlusal balance. Keeping in view of the significant relapse rate the clinicians are required to plan 15-20% excess amount of distraction.

  2. Evaluating the sensitivity, reproducibility and flexibility of a method to test hard shell capsules intended for use in dry powder inhalers.

    Science.gov (United States)

    Chong, Rosalind H E; Jones, Brian E; Díez, Fernando; Birchall, James C; Coulman, Sion A

    2016-03-16

    Pharmaceutical tests for hard shell capsules are designed for orally administered capsules. The use of capsules in dry powder inhalers is widespread and increasing and therefore more appropriate tests are required to ensure quality and determine if these capsules are fit for purpose. This study aims to determine the flexibility, reproducibility and sensitivity of a quantitative method that is designed to evaluate the puncture characteristics of different capsule shell formulations under different climatic conditions. A puncture testing method was used to generate force displacement curves for five capsule formulations that were stored and tested at two different temperatures (5°C and 19°C). Force-displacement puncture profiles were reproducible for individual capsule shell formulations. The methodology was able to discriminate between capsules produced using different primary materials i.e. gelatin versus hypromellose, as well as more minor changes to capsule formulation i.e. different material grades and excipients. Reduced temperature increased the forces required for capsule puncture however further work is required to confirm its significance. Results indicate the method provides a reproducible and sensitive means of evaluating capsule puncture. Future studies should validate the methodology at different test sites, using different operators and with different capsule shell formulations. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  3. Nanocrystalline β-Ta Coating Enhances the Longevity and Bioactivity of Medical Titanium Alloys

    Directory of Open Access Journals (Sweden)

    Linlin Liu

    2016-09-01

    Full Text Available A β-Ta nanocrystalline coating was engineered onto a Ti-6Al-4V substrate using a double cathode glow discharge technique to improve the corrosion resistance and bioactivity of this biomedical alloy. The new coating has a thickness of ~40 μm and exhibits a compact and homogeneous structure composed of equiaxed β-Ta grains with an average grain size of ~22 nm, which is well adhered on the substrate. Nanoindentation and scratch tests indicated that the β-Ta coating exhibited high hardness combined with good resistance to contact damage. The electrochemical behavior of the new coating was systematically investigated in Hank’s physiological solution at 37 °C. The results showed that the β-Ta coating exhibited a superior corrosion resistance as compared to uncoated Ti-6Al-4V and commercially pure tantalum, which was attributed to a stable passive film formed on the β-Ta coating. The in vitro bioactivity was studied by evaluating the apatite-forming capability of the coating after seven days of immersion in Hank’s physiological solution. The β-Ta coating showed a higher apatite-forming ability than both uncoated Ti-6Al-4V and commercially pure Ta, suggesting that the β-Ta coating has the potential to enhance functionality and increase longevity of orthopaedic implants.

  4. Hardness and adhesion performances of nanocoating on carbon steel

    Science.gov (United States)

    Hasnidawani, J. N.; Azlina, H. N.; Norita, H.; Bonnia, N. N.

    2018-01-01

    Nanocoatings industry has been aggressive in searching for cost-effective alternatives and environmental friendly approaches to manufacture products. Nanocoatings represent an engineering solution to prevent corrosion of the structural parts of ships, insulation and pipelines industries. The adhesion and hardness properties of coating affect material properties. This paper reviews ZnO-SiO2 as nanopowder in nano coating formulation as the agent for new and improved coating performances. Carbon steel on type S50C used as common substrate in nanocoating industry. 3wt% ZnO and 2wt% SiO2 addition of nanoparticles into nanocoating showed the best formulation since hardness and adhesion of nanocoating was good on carbon steel substrate. Incorporation of nanoparticles into coating increased the performances of coating.

  5. In-pile Hydrothermal Corrosion Evaluation of Coated SiC Ceramics and Composites

    Energy Technology Data Exchange (ETDEWEB)

    Carpenter, David [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States); Ang, Caen [Univ. of Tennessee, Knoxville, TN (United States); Katoh, Yutai [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Linton, Kory D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-09-01

    Hydrothermal corrosion accelerated by water radiolysis during normal operation is among the most critical technical feasibility issues remaining for silicon carbide (SiC) composite-based cladding that could provide enhanced accident-tolerance fuel technology for light water reactors. An integrated in-pile test was developed and performed to determine the synergistic effects of neutron irradiation, radiolysis, and pressurized water flow, all of which are relevant to a typical pressurized water reactor (PWR). The test specimens were chosen to cover a range of SiC materials and a variety of potential options for environmental barrier coatings. This document provides a summary of the irradiation vehicle design, operations of the experiment, and the specimen loading into the irradiation vehicle.

  6. Preparation and evaluation of glyceryl monooleate-coated hollow-bioadhesive microspheres for gastroretentive drug delivery.

    Science.gov (United States)

    Liu, Yuanfen; Zhang, Jianjun; Gao, Yuan; Zhu, Jiabi

    2011-07-15

    The purpose of this study was to produce hollow and bioadhesive microspheres to lengthen drug retention time in the stomach. In these microspheres, ethylcellulose was used as the matrix, Eudragit EPO was employed to modulate the release rate, and glyceryl monooleate (GMO) was the bioadhesive polymer in situ. The morphological characteristics of the microspheres were defined using scanning electron microscopy. The in vitro release test showed that the release rate of drug from the microspheres was pH-dependent, and was not influenced by the GMO coating film. The prepared microspheres demonstrated strong mucoadhesive properties with good buoyancy both in vitro and in vivo. Pharmacokinetic analysis indicated that the elimination half-life time of the hollow-bioadhesive microspheres was prolonged, and that the elimination rate was decreased. In conclusion, the hollow-bioadhesive synergic drug delivery system may be advantageous in the treatment of stomach diseases. Copyright © 2011 Elsevier B.V. All rights reserved.

  7. Evaluation of the Corrosion Protection Coating in Accordance with Burn Damage

    Energy Technology Data Exchange (ETDEWEB)

    Seo, ChangHo; Park, JinHwan [Pukyong National University, Busan (Korea, Republic of)

    2016-12-15

    This study was conducted in order to examine the effect of burn damage and the resultant anti-corrosion performance. The breakdown and defect of the paint film caused by burn damage are considered to affect not only the macroscopic appearance but also the adhesive force and the anti-corrosion performance of the paint film. The material of the paint film was epoxy paint that is used most widely for heavy-duty coating, and in order to induce burn damage, heat treatment with a torch was applied to the other side of the paint film. Surface and chemical structure changes according to aging were analyzed using FE-SEM and infrared absorption spectroscopy, and variation in the anti-corrosion performance was analyzed through the AC impedance test.

  8. Assessment of Automotive Coatings Used on Different Metallic Substrates

    Directory of Open Access Journals (Sweden)

    W. Bensalah

    2014-01-01

    Full Text Available Four epoxy primers commonly used in the automotive industry were applied by gravity pneumatic spray gun over metallic substrates, specifically, steel, electrogalvanized steel, hot-dip galvanized steel, and aluminum. A two-component polyurethane resin was used as topcoat. To evaluate the performance of the different coating systems, the treated panels were submitted to mechanical testing using Persoz hardness, impact resistance, cupping, lattice method, and bending. Tribological properties of different coating systems were conducted using pin on disc machine. Immersion tests were carried out in 5% NaCl and immersion tests in 3% NaOH solutions. Results showed which of the coating systems is more suitable for each substrate in terms of mechanical, tribological, and anticorrosive performance.

  9. In vitro evaluation of whole faba bean and its seed coat as a potential source of functional food components.

    Science.gov (United States)

    Çalışkantürk Karataş, Selen; Günay, Demet; Sayar, Sedat

    2017-09-01

    In vitro studies were conducted to evaluate the particular nutritional benefits of whole faba bean seed (WFB) and fava bean seed coat (FBSC). Total dietary fiber contents of WFB and FBSC were 27.5% and 82.3%, respectively. FBSC were contained much higher total phenolic substances, condensed tannins, and total antioxidant activity than WFB. Bile acid (BA)-binding capacities of in vitro digested samples and nutritionally important products produced by in vitro fermentation of digestion residues were also studied. The BA-binding capacities of WFB and FBSC were 1.94 and 37.50μmol/100mg, respectively. Total BA bound by FBSC was even higher than the positive standard cholestyramine. Lignin and other constituents of the Klason residue were found to influence BA-binding properties. Moreover, the extent of the in vitro fermentation process showed that, fermentability of FBSC residue was significantly lower than that of WFB residue. Overall, faba bean, especially its seed coat, has great potential as a functional food. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. Evaluation of the gold leaf thickness in the coating of the imperial horse-drawn carriage emperor D. Pedro II

    Energy Technology Data Exchange (ETDEWEB)

    Nardes, R.C.; Sanches, F.A.C.R.A.; Gama Filho, H.S.; Santos, R.S.; Oliveira, D.F.; Anjos, M.J.; Assis, J.T. [Universidade do Estado do Rio de Janeiro (UERJ), RJ (Brazil); Lopes, R.T. [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Laboratório de Instrumentação Nuclear; Carvalho, M.L. [Universidade Nova de Lisboa, Faculdade de Ciências e Tecnologia, Lisboa (Portugal); Zanatta, E.M. [Museu Imperial, Petropolis, RJ (Brazil). Laboratório de Conservação e Restauração; Cesareo, R., E-mail: rc.nardes@gmail.com [Instituto de Matemática e Física, Universidade de Sassari (Italy)

    2017-07-01

    In this study, the presence of gold in the coatings of the emperor D. Pedro’s II Berlin device, part of the Imperial Museum of Petropolis, Brazil, was verified. Then perform was evaluation of the thickness of the gold leaf, using the technique of X-Ray Fluorescence, measuring peak intensities (Kα / Kβ or Lα / Lβ) of the elements of interest in the layer. It was possible to verify in the XRF spectra the presence of four elements: Ti, Fe, Au and Pb. The Pb was present at all sampling points, which indicates the presence of lead carbonate (lead-white) as preparation layer. The presence of Au at some sampling points indicates that several parts of the Berlin devices were covered with gold leaf. The presence of Ti and Fe is due to the application of golden mica over the entire length of the berlin device during the process of last restoration. The presence of the mica layer on the gold covering was relevant for gold thickness determination. The average value of the gold thickness obtained was 0.62 ± 0.51 μm, with a coefficient of variation of 83% and a confidence interval of 0.49-0.75 μm (α = 0.05). The values are compatible with the thickness of gold foil normally found in the coating of pieces of wood from the same period that the Berlin device was built. (author)

  11. Testing of Flame Sprayed Al2O3 Matrix Coatings Containing TiO2

    Directory of Open Access Journals (Sweden)

    Czupryński A.

    2016-09-01

    Full Text Available The paper presents the results of the properties of flame sprayed ceramic coatings using oxide ceramic materials coating of a powdered aluminium oxide (Al2O3 matrix with 3% titanium oxide (TiO2 applied to unalloyed S235JR grade structural steel. A primer consisting of a metallic Ni-Al-Mo based powder has been applied to plates with dimensions of 5×200×300 mm and front surfaces of Ø40×50 mm cylinders. Flame spraying of primer coating was made using a RotoTec 80 torch, and an external coating was made with a CastoDyn DS 8000 torch. Evaluation of the coating properties was conducted using metallographic testing, phase composition research, measurement of microhardness, substrate coating adhesion (acc. to EN 582:1996 standard, erosion wear resistance (acc. to ASTM G76-95 standard, and abrasive wear resistance (acc. to ASTM G65 standard and thermal impact. The testing performed has demonstrated that flame spraying with 97% Al2O3 powder containing 3% TiO2 performed in a range of parameters allows for obtaining high-quality ceramic coatings with thickness up to ca. 500 µm on a steel base. Spray coating possesses a structure consisting mainly of aluminium oxide and a small amount of NiAl10O16 and NiAl32O49 phases. The bonding primer coat sprayed with the Ni-Al-Mo powder to the steel substrate and external coating sprayed with the 97% Al2O3 powder with 3% TiO2 addition demonstrates mechanical bonding characteristics. The coating is characterized by a high adhesion to the base amounting to 6.5 MPa. Average hardness of the external coating is ca. 780 HV. The obtained coatings are characterized by high erosion and abrasive wear resistance and the resistance to effects of cyclic thermal shock.

  12. Amorphous boron coatings produced with vacuum arc deposition technology

    CERN Document Server

    Klepper, C C; Yadlowsky, E J; Carlson, E P; Keitz, M D; Williams, J M; Zuhr, R A; Poker, D B

    2002-01-01

    In principle, boron (B) as a material has many excellent surface properties, including corrosion resistance, very high hardness, refractory properties, and a strong tendency to bond with most substrates. The potential technological benefits of the material have not been realized, because it is difficult to deposit it as coatings. B is difficult to evaporate, does not sputter well, and cannot be thermally sprayed. In this article, first successful deposition results from a robust system, based on the vacuum (cathodic) arc technology, are reported. Adherent coatings have been produced on 1100 Al, CP-Ti, Ti-6Al-4V, 316 SS, hard chrome plate, and 52 100 steel. Composition and thickness analyses have been performed by Rutherford backscattering spectroscopy. Hardness (H) and modules (E) have been evaluated by nanoindentation. The coatings are very pure and have properties characteristic of B suboxides. A microhardness of up to 27 GPa has been measured on a 400-nm-thick film deposited on 52 100 steel, with a corresp...

  13. Mechanisms of Military Coatings Degradation

    Science.gov (United States)

    2003-08-01

    volume and bulk film compaction. Coating A is a less sterically and thermally stable biuret trimer of HDI in comparison to the HDI of coating system...developed coatings systems used by the Army, Marine Corps and Air Force. This study has incorporated numerous analytical tools and methods in an effort to...blistering. Peel away was evaluated as per ASTM D 3359, Method A and blistering was evaluated as per ASTM D 714. Coating systems are summarized

  14. Fabrication of calcium phosphate films for coating on titanium substrates heated up to 773 K by RF magnetron sputtering and their evaluations

    Energy Technology Data Exchange (ETDEWEB)

    Ueda, Kyosuke [Department of Materials Processing, Tohoku University, 6-6-02 Aza Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Narushima, Takayuki [Tohoku University Biomedical Engineering Research Organization, 6-6-02 Aza Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan); Goto, Takashi [Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai, Miyagi 980-8577 (Japan); Taira, Masayuki [Department of Dental Materials and Technology, Iwate Medical University School of Dentistry, 1-3-27 Chuo-dori, Morioka, Iwate 020-8505 (Japan); Katsube, Tomoyuki [Tohoku University Biomedical Engineering Research Organization, 6-6-02 Aza Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980-8579 (Japan)

    2007-09-15

    Calcium phosphate films were fabricated on titanium substrates heated up to 773 K using radiofrequency (RF) magnetron sputtering. The deposition rate, phase and preferred orientation of the calcium phosphate films were studied. Immersion tests for the films were conducted using Hanks' solution and PBS(-), and the surface reactions on the specimens coated with the calcium phosphate films were investigated. The bonding strength between the coating films and the titanium substrates before and after the immersion tests was evaluated; the bonding strength decreased after the immersion tests. The alkaline phosphatase (ALP) activity of SaOS-2 cells on a titanium plate coated with a calcium phosphate film was examined by conducting a culture test. Calcium phosphate coating increased the ALP activity of SaOS-2 cells cultured for 3 and 7 days. Titanium cylinders were coated with an amorphous calcium phosphate film and implanted into the mandibles of beagle dogs. An increase in the extent of bone-implant contact for the coated titanium cylinders was confirmed 8 to 12 weeks after implantation and compared with the case for uncoated titanium cylinders.

  15. A novel paclitaxel-eluting porous carbon-carbon nanoparticle coated, nonpolymeric cobalt-chromium stent: evaluation in a porcine model.

    Science.gov (United States)

    Bhargava, Balram; Reddy, N Krishna; Karthikeyan, Ganesan; Raju, Raghava; Mishra, Sundeep; Singh, Sandeep; Waksman, Ron; Virmani, Renu; Somaraju, B

    2006-05-01

    We aimed to evaluate the response of porcine coronary arteries to a novel paclitaxel-eluting porous carbon-carbon nanoparticle coated, nonpolymeric cobalt chromium stent. Polymer based drug-eluting stents significantly reduce restenosis. However, the indefinite presence of polymer is thought to initiate and sustain inflammation and contribute to the occurrence of late complications. Sixteen carbon-carbon coated, nonpolymeric cobalt chromium stents with two different doses of paclitaxel (eight of each) were implanted in porcine coronary arteries. In addition, eight cobalt chromium stents coated with a biodegradable polymer were also studied. Animals were sacrificed 6 weeks after stent implantation and histomorphometric analysis was performed. Results were compared among the three groups of stents. The cobalt chromium stents coated with carbon-carbon with low and medium doses of paclitaxel both showed acceptable performance characteristics, with respect to endothelialization, neointimal hyperplasia, percentage diameter stenosis, inflammatory response, and tendency to fibrin deposition, when compared to historical data with the Cypher stent. On the other hand, the stents coated with poly(lactide) and poly(lactide-co-glycolide) biodegradable polymers and 0.7 microg/mm2 paclitaxel showed poor performance. There was a significant tendency to poor endothelialization, greater neointimal hyperplasia, percentage diameter stenosis, greater inflammatory response, and tendency to fibrin deposition (P cobalt chromium stent with a carbon-carbon coating and low and medium doses of paclitaxel. (c) 2006 Wiley-Liss, Inc.

  16. A Novel Approach for Dry Powder Coating of Pellets with Ethylcellulose. Part II: Evaluation of Caffeine Release.

    Science.gov (United States)

    Albertini, Beatrice; Melegari, Cecilia; Bertoni, Serena; Dolci, Luisa Stella; Passerini, Nadia

    2018-02-13

    The objective of this study was to assess the efficacy and the capability of a novel ethylcellulose-based dry-coating system to obtain prolonged and stable release profiles of caffeine-loaded pellets. Lauric and oleic acids at a suitable proportion were used to plasticize ethylcellulose. The effect of coating level, percentage of drug loading, inert core particle size, and composition of the coating formulation including the anti-sticking agent on the drug release profile were fully investigated. A coating level of 15% w/w was the maximum layered amount which could modify the drug release. The best controlled drug release was obtained by atomizing talc (2.5% w/w) together with the solid plasticizer during the dry powder-coating process. SEM pictures revealed a substantial drug re-crystallization on the pellet surface, and the release studies evidenced that caffeine diffused through the plasticized polymer acting as pore former. Therefore, the phenomenon of caffeine migration across the coating layer had a strong influence on the permeability of the coating membrane. Comparing dry powder-coated pellets to aqueous film-coated ones, drug migration happened during storage, though more sustained release profiles were obtained. The developed dry powder-coating process enabled the production of stable caffeine sustained release pellets. Surprisingly, the release properties of the dry-coated pellets were mainly influenced by the way of addition of talc into the dry powder-coating blend and by the drug nature and affinity to the coating components. It would be interesting to study the efficacy of novel coating system using a different API.

  17. Evaluation of bulk and surfaces absorption edge energy of sol-gel-dip-coating SnO2 thin films

    Directory of Open Access Journals (Sweden)

    Emerson Aparecido Floriano

    2010-12-01

    Full Text Available The absorption edge and the bandgap transition of sol-gel-dip-coating SnO2 thin films, deposited on quartz substrates, are evaluated from optical absorption data and temperature dependent photoconductivity spectra. Structural properties of these films help the interpretation of bandgap transition nature, since the obtained nanosized dimensions of crystallites are determinant on dominant growth direction and, thus, absorption energy. Electronic properties of the bulk and (110 and (101 surfaces are also presented, calculated by means of density functional theory applied to periodic calculations at B3LYP hybrid functional level. Experimentally obtained absorption edge is compared to the calculated energy band diagrams of bulk and (110 and (101 surfaces. The overall calculated electronic properties in conjunction with structural and electro-optical experimental data suggest that the nature of the bandgap transition is related to a combined effect of bulk and (101 surface, which presents direct bandgap transition.

  18. A new approach to local hardness

    CERN Document Server

    Gal, T; De Proft, F; Torrent-Sucarrat, M

    2011-01-01

    The applicability of the local hardness as defined by the derivative of the chemical potential with respect to the electron density is undermined by an essential ambiguity arising from this definition. Further, the local quantity defined in this way does not integrate to the (global) hardness - in contrast with the local softness, which integrates to the softness. It has also been shown recently that with the conventional formulae, the largest values of local hardness do not necessarily correspond to the hardest regions of a molecule. Here, in an attempt to fix these drawbacks, we propose a new approach to define and evaluate the local hardness. We define a local chemical potential, utilizing the fact that the chemical potential emerges as the additive constant term in the number-conserving functional derivative of the energy density functional. Then, differentiation of this local chemical potential with respect to the number of electrons leads to a local hardness that integrates to the hardness, and possesse...

  19. Evaluation of regional fracture properties for groundwater development using hydrolithostructural domain approach in variably fractured hard rocks of Purulia district, West Bengal, India

    Science.gov (United States)

    Acharya, Tapas; Prasad, Rajesh; Chakrabarti, S.

    2014-04-01

    Estimation of geohydrologic properties of fractured aquifers in hard crystalline and/or metamorphosed country rocks is a challenge due to the complex nature of secondary porosity that is caused by differential fracturing. Hydrologic potentiality of such aquifers may be assessed if the geological controls governing the spatial distribution of these fracture systems are computed using a software-based model. As an exemplar, the Precambrian metamorphics exposed in and around the Balarampur town of Purulia district, West Bengal (India) were studied to find out the spatial pattern and consistency of such fracture systems. Surfer and Statistica softwares were used to characterize these rock masses in terms of hydrological, structural and lithological domains. The technique is based on the use of hydraulically significant fracture properties to generate representative modal and coefficient of variance ( Cν) of fracture datasets of each domain. The Cν is interpreted to obtain the spatial variability of hydraulically significant fracture properties that, in turn, define and identify the corresponding hydrolithostructural domains. The groundwater flow estimated from such a technique is verified with the routine hydrological studies to validate the procedure. It is suggested that the hydrolithostructural domain approach is a useful alternative for evaluation of fracture properties and aquifer potentiality, and development of a regional groundwater model thereof.

  20. Coated particle waste form development

    Energy Technology Data Exchange (ETDEWEB)

    Oma, K.H.; Buckwalter, C.Q.; Chick, L.A.

    1981-12-01

    Coated particle waste forms have been developed as part of the multibarrier concept at Pacific Northwest Laboratory under the Alternative Waste Forms Program for the Department of Energy. Primary efforts were to coat simulated nuclear waste glass marbles and ceramic pellets with low-temperature pyrolytic carbon (LT-PyC) coatings via the process of chemical vapor deposition (CVD). Fluidized bed (FB) coaters, screw agitated coaters (SAC), and rotating tube coaters were used. Coating temperatures were reduced by using catalysts and plasma activation. In general, the LT-PyC coatings did not provide the expected high leach resistance as previously measured for carbon alone. The coatings were friable and often spalled off the substrate. A totally different concept, thermal spray coating, was investigated at PNL as an alternative to CVD coating. Flame spray, wire gun, and plasma gun systems were evaluated using glass, ceramic, and metallic coating materials. Metal plasma spray coatings (Al, Sn, Zn, Pb) provided a two to three orders-of-magnitude increase in chemical durability. Because the aluminum coatings were porous, the superior leach resistance must be due to either a chemical interaction or to a pH buffer effect. Because they are complex, coated waste form processes rank low in process feasibility. Of all the possible coated particle processes, plasma sprayed marbles have the best rating. Carbon coating of pellets by CVD ranked ninth when compared with ten other processes. The plasma-spray-coated marble process ranked sixth out of eleven processes.

  1. Evaluation of Rosin Gum and Eudragit® RS PO as a Functional Film Coating Material.

    Science.gov (United States)

    Pomin, Suélen Plaza; de Lima, Isabela Angeli; Pezarini, Rogério Ribeiro; Cavalcanti, Osvaldo Albuquerque

    2017-11-01

    Polymers are essential tools in the research and development of new therapeutic devices. The diversity and flexibility of these materials have generated high expectations in the composition of new materials with extraordinary abilities, especially in the design of new systems for the modified release of pharmaceutically active ingredients. The natural polymer rosin features moisture protection and pH-dependent behavior (i.e., it is sensitive to pH > 7.0), suggesting its possible use in pharmaceutical systems. The synthetic polymer Eudragit® RS PO is a low-permeability material, the disintegration of which depends on the time of residence in the gastrointestinal tract. The present study developed a polymeric material with desirable physicochemical characteristics and synergistic effects that resulted from the inherent properties of the associated polymers. Isolated films were obtained by solvent evaporation and subjected to a water vapor transmission test, scanning electron microscopy, calorimetry, Fourier transform-infrared (FT-IR) spectroscopy, micro-Raman spectroscopy, and mechanical analysis. The new polymeric material was macroscopically continuous and homogeneous, was appropriately flexible, had low water permeability, was vulnerable in alkaline environments, and was thermally stable, maintaining an unchanged structure up to temperatures of ∼400°C. The new material also presented potentially suitable characteristics for application in film coatings for oral solids, suggesting that it is capable of carrying therapeutic substances to distal regions of the gastrointestinal tract. These findings indicate that this new material may be added to the list of functional excipients.

  2. Six-Year Evaluation of Thermal-Sprayed Coating of Zn/Al in Tropical Marine Environments

    Directory of Open Access Journals (Sweden)

    Orlando Salas

    2012-01-01

    Full Text Available The main objective of this research was to evaluate the performance of thermal-sprayed coating of Zn/Al (double layer after six years of exposure, with and without the use of sealant (wash primer in tropical marine environments of very high aggressiveness: La Voz Station (located at the Peninsula de Paraguaná/Falcón State and Lake Maracaibo Crossing Station (located at Zulia State, in Venezuela. To that effect, carbon steel coupons (100 mm × 150 mm × 2 mm were sprayed by flame process. The coupons were characterized by means of initial weight, thickness, metallographic, adherence, and roughness, being evaluated monthly by visual inspection during six years. After removal, the coupons were evaluated by microscopic analysis to determine the morphology of attack, microstructure, penetration of contaminants, composition, and morphology of corrosion products. The results showed that after six years, the double-layer system represents an excellent choice for corrosion protection of steel by combining the galvanic protection of zinc with the erosion resistance of aluminum. However, due to the erosion-corrosion effect, a sealant such as wash primer can be used in order to extend its service life.

  3. Evaluation of Carbon Nanotubes Functionalized Polydimethylsiloxane Based Coatings for In-Tube Solid Phase Microextraction Coupled to Capillary Liquid Chromatography

    Directory of Open Access Journals (Sweden)

    Neus Jornet-Martínez

    2015-08-01

    Full Text Available In the present work, the performance of carbon nanotubes (c-CNTs functionalized polydimethylsiloxane (PDMS based coatings as extractive phases for in-tube solid phase microextraction (IT-SPME coupled to Capillary LC (CapLC has been evaluated. Carboxylic-single walled carbon nanotubes (c-SWNTs and carboxylic-multi walled carbon nanotubes (c-MWNTs have been immobilized on the activated surface of PDMS capillary columns. The effect of different percentages of diphenyl groups in the PDMS extractive phase has also been evaluated. The extraction capability of the capillary columns has been tested for different organic pollutants, nitrogen heterocyclic compounds and polycyclic aromatic compounds (PAHs. The results indicated that the use of the c-CNTs-PDMS capillary columns improve pyriproxyfen and mainly PAH extraction. Triazines were better extracted by unmodified TRB-35 and modified c-CNTs-PDMSTRB-5. The results showed that the extraction capability of the c-CNT capillary columns depends not only on the polarity of the analytes (as it occurs with PDMS columns but also on the interactions that the analytes can establish with the immobilized c-CNTs on the PDMS columns. The extraction efficiency has been evaluated on the basis of the preconcentration rate that can be achieved, and, in this sense, the best c-CNTs-PDMS capillary column for each group of compounds can be proposed.

  4. Tribology of polymeric coatings for aggressive bearing applications

    Science.gov (United States)

    Yeo, Seung Min

    To meet the higher performance requirements of today's air-conditioning and refrigeration (ACR) compressors, their operating conditions have been getting harsher under higher speed and load, thus making tribological characteristics of interacting surfaces playing a significant role in compressor's reliability. However, the capabilities of conventional fluid lubricants are limited such that the state of lubrication is usually unknown, and, at best, in the boundary/mixed lubrication regimes. Therefore, it becomes necessary to implement some type of advanced protective coatings on the interacting surfaces to withstand stringent contact conditions. Due to favorable tribological performance, polytetrafluoroethylene (PTFE)- and polyetheretherketone (PEEK)-based polymeric coatings have received interest in ACR compressor applications, as a potential solution to supplement and potentially replace conventional oil lubricants. However, compared to a great amount of research and experiments done so far for bulk of polymers, there is limited literature on the tribological performance of PTFE- and PEEK-based polymeric coatings. In this work, several PTFE-, PEEK-, resin- and fluorocarbon-based polymeric coatings, coated on gray cast iron were tribologically evaluated using a specialized tribometer under compressor specific conditions. The coatings showed good to excellent tribological performance, and in general PTFE-based coatings exhibited better friction and wear behavior than the rest of the coatings, including PEEK-based coatings. The micromechanical properties of polymeric coatings were examined using instrumented microindentation. The load-unload responses were used to measure the load-bearing properties of the coatings, as well as to extract their elastic modulus and hardness values. Induced structural differences between the PTFE- and PEEK-based coatings were confirmed using scanning electron microscopy. These measurements were used to explain the difference in the

  5. Functional Plasma-Deposited Coatings

    Directory of Open Access Journals (Sweden)

    Mykhaylo Pashechko

    2017-12-01

    Full Text Available The paper focuses on the problem of low adhesion of plasma sprayed coatings to the substrate. The subsequent laser treatment modes and their influence on the coating-substrate interface were studied. This allows to decrease the level of metstability of the coating, thus decreasing its hardness down to 11-12 GPa on the surface and to about 9 GPa on depth of 400 µm. The redistribution of alloying elements through solid and liquid diffusion improves mechanical properties and rises the adhesion up to 450 MPa after remelting and up to 90-110 MPa after laser-aided thermal cycling. At he same time, remelting of coating helps to decrease its porosity down to 1%. Obtained complex of properties also allows to improve wear resistance of coatings and to decrease friction factor.

  6. UV-B absorbing compounds in present-day and fossil pollen, spores, cuticles seed coats and wood: evaluation of a proxy for solar UV-B radiation.

    NARCIS (Netherlands)

    Rozema, J.; Blokker, P.; Mayoral Fuertes, M.; Broekman, R.A.

    2009-01-01

    UV-B absorbing compounds (UACs) in present-day and fossil pollen, spores, cuticles, seed coats and wood have been evaluated as a proxy for past UV. This proxy may not only provide information on variation of stratospheric ozone and solar UV in the period preceding and during the Antarctic ozone hole

  7. Evaluation of mechanical property and bioactivity of nano-bioglass 45S5 scaffold coated with poly-3-hydroxybutyrate.

    Science.gov (United States)

    Montazeri, Mahbobeh; Karbasi, Saeed; Foroughi, Mohammad Reza; Monshi, Ahmad; Ebrahimi-Kahrizsangi, Reza

    2015-02-01

    One of the major challenges facing researchers of tissue engineering is scaffold design with desirable physical and mechanical properties for growth and proliferation of cells and tissue formation. In this research, firstly, nano-bioglass powder with grain sizes of 55-56 nm was prepared by melting method of industrial raw materials at 1,400 °C. Then the porous ceramic scaffold of bioglass with 30, 40 and 50 wt% was prepared by using the polyurethane sponge replication method. The scaffolds were coated with poly-3-hydroxybutyrate (P3HB) for 30 s and 1 min in order to increase the scaffold's mechanical properties. XRD, XRF, SEM, FE-SEM and FT-IR were used for phase and component studies, morphology, particle size and determination of functional groups, respectively. XRD and XRF results showed that the type of the produced bioglass was 45S5. The results of XRD and FT-IR showed that the best temperature to produce bioglass scaffold was 600 °C, in which Na2Ca2Si3O9 crystal is obtained. By coating the scaffolds with P3HB, a composite scaffold with optimal porosity of 80-87% in 200-600 μm and compression strength of 0.1-0.53 MPa was obtained. According to the results of compressive strength and porosity tests, the best kind of scaffold was produced with 30 wt% of bioglass immersed for 1 min in P3HB. To evaluate the bioactivity of the scaffold, the SBF solution was used. The selected scaffold (30 wt% bioglass/6 wt% P3HB) was maintained for up to 4 weeks in this solution at an incubation temperature of 37 °C. The XRD, SEM EDXA and AAS tests were indicative of hydroxyapatite formation on the surface of bioactive scaffold. This scaffold has some potential to use in bone tissue engineering.

  8. Biological and immunotoxicity evaluation of antimicrobial peptide-loaded coatings using a layer-by-layer process on titanium

    Science.gov (United States)

    Shi, Jue; Liu, Yu; Wang, Ying; Zhang, Jing; Zhao, Shifang; Yang, Guoli

    2015-11-01

    The prevention and control of peri-implantitis is a challenge in dental implant surgery. Dental implants with sustained antimicrobial coating are an ideal way of preventing peri-implantitis. This study reports development of a non- immunotoxicity multilayered coating on a titanium surface that had sustained antimicrobial activity and limited early biofilm formation. In this study, the broad spectrum AMP, Tet213, was linked to collagen IV through sulfo-SMPB and has been renamed as AMPCol. The multilayer AMPCol coatings were assembled on smooth titanium surfaces using a LBL technique. Using XPS, AFM, contact angle analysis, and QCM, layer-by-layer accumulation of coating thickness was measured and increased surface wetting compared to controls was confirmed. Non-cytotoxicity to HaCaT and low erythrocyte hemolysis by the AMPCol coatings was observed. In vivo immunotoxicity assays showed IP administration of AMPCol did not effect serum immunoglobulin levels. This coating with controlled release of AMP decreased the growth of both a Gram-positive aerobe (Staphylococcus aureus) and a Gram-negative anaerobe (Porphyromonas gingivalis) up to one month. Early S. aureus biofilm formation was inhibited by the coating. The excellent long-term sustained antimicrobial activity of this multilayer coating is a potential method for preventing peri-implantitis through coated on the neck of implants before surgery.

  9. Fluoropolymer - TiO2 coatings and their superhydrophilicity

    DEFF Research Database (Denmark)

    Søgaard, Erik Gydesen; Simonsen, Morten Enggrob; Jepsen, Henrik

    of a statistical planning procedure. The dip coating of object glass with 24 different mixtures created the basis for the investigation. A water droplet was put on the surface of each coating and in total 1900 images of its contact angle were taken as function of time. Hardness of the coatings were measured...

  10. High-Throughput Industrial Coatings Research at The Dow Chemical Company.

    Science.gov (United States)

    Kuo, Tzu-Chi; Malvadkar, Niranjan A; Drumright, Ray; Cesaretti, Richard; Bishop, Matthew T

    2016-09-12

    At The Dow Chemical Company, high-throughput research is an active area for developing new industrial coatings products. Using the principles of automation (i.e., using robotic instruments), parallel processing (i.e., prepare, process, and evaluate samples in parallel), and miniaturization (i.e., reduce sample size), high-throughput tools for synthesizing, formulating, and applying coating compositions have been developed at Dow. In addition, high-throughput workflows for measuring various coating properties, such as cure speed, hardness development, scratch resistance, impact toughness, resin compatibility, pot-life, surface defects, among others have also been developed in-house. These workflows correlate well with the traditional coatings tests, but they do not necessarily mimic those tests. The use of such high-throughput workflows in combination with smart experimental designs allows accelerated discovery and commercialization.

  11. Advanced Gas Cooled Nuclear Reactor Materials Evaluation and Development Program: Topical report I, selection of candidate alloys. Volume 3. Selection of surface coating/substrate systems for screening creep and structural stability studies

    Energy Technology Data Exchange (ETDEWEB)

    1980-06-20

    Considering the high temperature, low O/sub 2/, high C environment of operation in the Very High Temperature Reactor (VHTR) Systems, the utilization of coatings is envisaged to hold potential for extending component lifetimes through the formation of stable and continuous oxide films with enhanced resistance to C diffusion. A survey of the current state of technology for high temperature coatings has been performed. The usefulness of these coatings on the Mo, Ni, and Fe base alloys is discussed. Specifically, no coating substitute was identified for TZM other than the well known W-3 (pack silicide) and Al/sub 2/O/sub 3/ forming coatings were recommended for the Fe and Ni base structural materials. Recommendations as to coating types and processng have been made based on the predicted VHTR component size, shape, base metal and operational environment. Four tests designed to evaluate the effects of selected combinations of coatings and substrate matrices are recommended for consideration.

  12. Evaluation of Monolithic Ceramics and Ceramic Thermal Barrier Coatings for Diesel Engine Applications

    National Research Council Canada - National Science Library

    Swab, Jeffrey J

    2001-01-01

    The Metals and Ceramics Research Branch (MCRB) of the Weapons and Materials Research Directorate is providing ceramic material characterization and evaluation to the Tank Automotive Research, Development, and Engineering Center (TARDEC...

  13. EVALUATION OF SUPERCRITICAL CARBON DIOXIDE TECHNOLOGY TO REDUCE SOLVENT IN SPRAY COATING APPLICATIONS

    Science.gov (United States)

    This evaluation, part of the Pollution Prevention Clean Technology Demonstration (CTD) Program, addresses the product quality, waste reduction, and economic issues of spray paint application using supercritical carbon dioxide (CO2). Anion Carbide has developed this technology and...

  14. In vivo evaluation of CaO-SiO2-P2O5-B2O3 glass-ceramics coating on Steinman pins.

    Science.gov (United States)

    Lee, Jae Hyup; Hong, Kug Sun; Baek, Hae-Ri; Seo, Jun-Hyuk; Lee, Kyung Mee; Ryu, Hyun-Seung; Lee, Hyun-Kyung

    2013-07-01

    Surface coating using ceramics improves the bone bonding strength of an implant. We questioned whether a new type of glass-ceramics (BGS-7) coating (CaO-SiO2 -P2 O5 -B2 O3 ) would improve the osseointegration of Steinman pins (S-pins) both biomechanically and histomorphometrically. An in vivo study was performed using rabbits by inserting three S-pins into each iliac bone. The pins were 2.2-mm S-pins with a coating of 30-μm-thick BGS-7 and 550-nm-thick hydroxyapatite (HA), as opposed to an S-pin without coating. A tensile strength test and histomorphometrical evaluation was performed. In the 2-week group, the BGS-7 implant showed a significantly higher tensile strength than the S-pin. In the 4- and 8-week groups, the BGS-7 implants had significantly higher tensile strengths than the S-pins and HA implants. The histomorphometrical study revealed that the BGS-7 implant had a significantly higher contact ratio than the S-pin and HA implants in the 4-week group. The biomechanical and histomorphometrical tests showed that the BGS-7 coating had superior bone bonding properties than the groups without the coating from the initial stage of insertion. The BGS-7 coating of an S-pin will enhance the bone bonding strength, and there might also be an advantage in human bone bonding. © 2013, Copyright the Authors. Artificial Organs © 2013, International Center for Artificial Organs and Transplantation and Wiley Periodicals, Inc.

  15. Study on the Tribological Behaviors of Different PEEK Composite Coatings for Use as Artificial Cervical Disk Materials

    Science.gov (United States)

    Song, Jian; Liao, Zhenhua; Wang, Song; Liu, Yuhong; Liu, Weiqiang; Tyagi, Rajnesh

    2016-01-01

    Poly(ether-ether-ketone) (PEEK) is a type of biomaterial which may be used for modifying the surface of materials used in implants. Hence, in the present investigation, the potentiality of PEEK and its composites coatings has been explored for improving the friction and wear behavior of the Ti6Al4V to be used for cervical disks. The structural characteristics, micro-hardness, friction, and wear characteristics of PEEK/Al2O3 and PEEK/SiO2 composite coatings have been investigated and compared with pure PEEK coating and bare titanium alloy sample. According to the XRD analysis results, these coated samples were mainly orthorhombic crystalline form. The contact angle values of PEEK and its composite coatings were higher, while micro-hardness values of these samples decreased significantly. The thickness values of the three coated samples were all above 70 μm on average. The average friction coefficients with a counterface of ZrO2 ball decreased significantly, especially under NCS (newborn calf serum) lubricated condition. After comprehensive evaluation, the PEEK/Al2O3 coating demonstrated optimum tribological properties and could be applied as bearing materials for artificial cervical disk.

  16. Zircon-Based Ceramic Coatings Formed by a New Multi-Chamber Gas-Dynamic Accelerator

    Directory of Open Access Journals (Sweden)

    Marina Kovaleva

    2017-09-01

    Full Text Available In this work, dense zircon-based ceramic coatings were obtained from inexpensive zircon powder on a steel substrate by using a new multi-chamber gas-dynamic accelerator. The microstructure and phase composition of the coating were characterized by scanning electron microscopy, optical microscopy, and X-ray diffraction. The mechanical properties of the coatings were evaluated using microindentation, wear tests and bonding strength tests. The results showed that the obtained zircon-based ceramic coatings were continuous without cracks and bonded well with substrate without a sublayer. The zircon-based ceramic coatings consisted of c-ZrO2 (major phase, m-ZrO2 and SiO2. The zircon-based ceramic coatings had a porosity of 0.1%, hardness of 526 ± 65 HV0.2, and a fracture toughness of 2.5 ± 0.6 (МPа∙m1/2. The coatings showed the low specific wear rate and average erosion rate. The failure mode occurring in the tested coatings was cohesive.

  17. A multifaceted coating on titanium dictates osteoimmunomodulation and osteo/angio-genesis towards ameliorative osseointegration.

    Science.gov (United States)

    Bai, Long; Du, Zhibin; Du, Jingjing; Yao, Wei; Zhang, Jiaming; Weng, Zeming; Liu, Si; Zhao, Ya; Liu, Yanlian; Zhang, Xiangyu; Huang, Xiaobo; Yao, Xiaohong; Crawford, Ross; Hang, Ruiqiang; Huang, Di; Tang, Bin; Xiao, Yin

    2018-04-01

    A multifaceted coating for hard tissue implants, with favorable osteogenesis, angiogenesis, and osteoimmunomodulation abilities, would be of great value since it could improve osseointegration and alleviate prosthesis loosening. However, to date there are few coatings that fully satisfy these criteria. Herein we describe a microporous TiO 2 coating decorated with hydroxyapatite (HA) nanoparticles that is generated by micro-arc oxidation of pure titanium (Ti) and followed annealing. By altering the annealing temperature, it is possible to simultaneously tune the coating's physical (morphology and wettability) and chemical (composites and crystallinity) properties. A coating produced with micro-arc oxidization (MAO) with an annealing temperature of 650 °C (MAO-650) exhibits numerous favorable physicochemical properties, such as hybrid micro-nano morphology, superhydrophilicity, and highly crystalline HA nanoparticles. In vitro experiments reveal that the MAO-650 coating not only supports proliferation and differentiation of both osteoblasts and endothelial cells, but also inhibits the inflammatory response of macrophages and enables a favorable osteoimmunomodulation to facilitate osteo/angio-genesis. In vivo evaluation mirrors these results, and shows that the MAO-650 coating results in ameliorative osseointegration when compared with the pristine MAO coating. These data highlight the profound effect of surface physicochemical properties on the regulation of osteo/angio-genesis and osteoimmunomodulation in the enhancement of osseointegration. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

  18. Identification and evaluation of the probiotic potential of Lactobacillus paraplantarum FT259, a bacteriocinogenic strain isolated from Brazilian semi-hard artisanal cheese.

    Science.gov (United States)

    Tulini, Fabrício Luiz; Winkelströter, Lizziane Kretli; De Martinis, Elaine C P

    2013-08-01

    This study aimed to identify a bacteriocinogenic Lactobacillus isolate (FT259) obtained from Brazilian semi-hard Minas type cheese and to evaluate its probiotic and antimicrobial potentials. The strain was identified by biochemical tests (at genus level), and by 16S rDNA sequencing combined with recA gene amplification (for species). To determine the inhibitory spectrum towards food borne pathogens and lactic acid bacteria, the spot-on-the-lawn assay was carried out. Moreover, the proteinaceous nature of the antimicrobial compound produced was evaluated by susceptibility to degradation by proteolytic enzymes. The isolated strain was tested for survival in acidified culture media (pH 2.0, 2.5 and 3.5), in vitro tolerance to bile salts and viability under gastric conditions. Adhesion of Lactobacillus paraplantarum FT259 to Caco-2 cells was evaluated by surface plate count on De Man, Rogosa, and Sharpe (MRS) agar and also by FISH method (fluorescent in situ hybridization) with the aid of Eub338 probe for fluorescence microscopy analysis. The isolate was identified as L. paraplantarum FT259 and it produced bacteriocins that inhibited the growth of Listeria monocytogenes, Listeria innocua and several lactic acid bacteria. It was also observed that L. paraplantarum FT259 tolerated exposure to pH 3.5, and bile salts 0.3% for up to 180 min. In experiments with simulated gastric juice, viable cells of L. paraplantarum FT259 decreased from 8.6 log CFU/mL to 3.5 log CFU/mL after 180 min. For the same strain, in studies with Caco-2 cells, 74% of adhesion was observed through plate count and FISH assays. It was also demonstrated isolated FT259 was susceptible to the majority the antibiotics tested. Overall, the results indicated L. paraplantarum FT259 is a potential probiotic and the production of bacteriocin may be an interesting feature for food applications. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. Blending “Hard” and “Soft” Science: the “Follow-the-Technology” Approach to Catalyzing and Evaluating Technology Change

    Directory of Open Access Journals (Sweden)

    Boru Douthwaite

    2002-01-01

    Full Text Available The types of technology change catalyzed by research interventions in integrated natural resource management (INRM are likely to require much more social negotiation and adaptation than are changes related to plant breeding, the dominant discipline within the system of the Consultative Group on International Agricultural Research (CGIAR. Conceptual models for developing and delivering high-yielding varieties have proven inadequate for delivering natural resource management (NRM technologies that are adopted in farmers' fields. Successful INRM requires tools and approaches that can blend the technical with the social, so that people from different disciplines and social backgrounds can effectively work and communicate with each other. This paper develops the "follow-the-technology" (FTT approach to catalyzing, managing, and evaluating rural technology change as a framework that both "hard" and "soft" scientists can work with. To deal with complexity, INRM needs ways of working that are adaptive and flexible. The FTT approach uses technology as the entry point into a complex situation to determine what is important. In this way, it narrows the research arena to achievable boundaries. The methodology can also be used to catalyze technology change, both within and outside agriculture. The FTT approach can make it possible to channel the innovative potential of local people that is necessary in INRM to "scale up" from the pilot site to the landscape. The FTT approach is built on an analogy between technology change and Darwinian evolution, specifically between "learning selection" and natural selection. In learning selection, stakeholders experiment with a new technology and carry out the evolutionary roles of novelty generation, selection, and promulgation. The motivation to participate is a "plausible promise" made by the R&D team to solve a real farming problem. Case studies are presented from a spectrum of technologies to show that repeated

  20. Preparation and evaluation of APTES-PEG coated iron oxide nanoparticles conjugated to rhenium-188 labeled rituximab.

    Science.gov (United States)

    Azadbakht, Bakhtiar; Afarideh, Hossein; Ghannadi-Maragheh, Mohammad; Bahrami-Samani, Ali; Asgari, Mehdi

    2017-05-01

    Radioimmuno-conjugated (Rhenium-188 labeled Rituximab), 3-aminopropyltriethoxysilane (APTES)-polyethylene glycol (PEG) coated iron oxide nanoparticles were synthesized and then characterized. Therapeutic effect and targeting efficacy of complex were evaluated in CD20 express B cell lines and tumor bearing Balb/c mice respectively. To reach these purposes, superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized using coprecipitation method and then their surface was treated with APTES for increasing retention time of SPIONs in blood circulation and amine group creation. In the next step, N-hydroxysuccinimide (NHS) ester of polyethylene glycol maleimide (NHS-PEG-Mal) was conjugated to the APTES-treated SPIONs. After radiolabeling of Rituximab antibody with Rhenium-188 (T1/2=16.9h) using synthesized N2S4 chelator, it was attached to the APTES-PEG-MAL-SPIONs surface through thiol-maleimide coupling reaction. In vitro evaluation of the (188)ReN2S4-Rituximab-SPION-complex thus obtained revealed that at 24 and 48h post-treatment effective cancer cell killing had been achieved. Bio-distribution study in tumor bearing mice showed capability of this complex for targeted cancer therapy. Active and passive tumor targeting strategies were applied through incorporated anti-CD20 (Rituximab) antibody and also enhanced permeability and retention (EPR) effect of solid tumors for nanoparticles respectively. Copyright © 2016 Elsevier Inc. All rights reserved.

  1. Evaluation of 3D-Printed Polycaprolactone Scaffolds Coated with Freeze-Dried Platelet-Rich Plasma for Bone Regeneration.

    Science.gov (United States)

    Li, Junda; Chen, Meilin; Wei, Xiaoying; Hao, Yishan; Wang, Jinming

    2017-07-19

    Three-dimensional printing is one of the most promising techniques for the manufacturing of scaffolds for bone tissue engineering. However, a pure scaffold is limited by its biological properties. Platelet-rich plasma (PRP) has been shown to have the potential to improve the osteogenic effect. In this study, we improved the biological properties of scaffolds by coating 3D-printed polycaprolactone (PCL) scaffolds with freeze-dried and traditionally prepared PRP, and we evaluated these scaffolds through in vitro and in vivo experiments. In vitro, we evaluated the interaction between dental pulp stem cells (DPSCs) and the scaffolds by measuring cell proliferation, alkaline phosphatase (ALP) activity, and osteogenic differentiation. The results showed that freeze-dried PRP significantly enhanced ALP activity and the mRNA expression levels of osteogenic genes (ALP, RUNX2 (runt-related gene-2), OCN (osteocalcin), OPN (osteopontin)) of DPSCs (p 3D-printed PCL scaffolds with freeze-dried PRP can promote greater osteogenic differentiation of DPSCs and induce more bone formation, which may have great potential in future clinical applications.

  2. Evaluation of coating thickness by thermal wave imaging: A comparative study of pulsed and lock-in infrared thermography - Part I: Simulation

    Science.gov (United States)

    Shrestha, Ranjit; Kim, Wontae

    2017-06-01

    This paper investigates the possibilities of evaluating non-uniform coating thickness using thermal wave imaging method. A comparative study of pulsed thermography (PT) and lock-in thermography (LIT) based on evaluating the accuracy of predicted coating thickness is presented. In this study, a transient thermal finite element model was created in ANSYS 15. A single square pulse heating for PT and a sinusoidal heating at different modulation frequencies for LIT were used to stimulate the sample according to the experimental procedures. The response of thermally excited surface was recorded and data processing with Fourier transform was carried out to obtain the phase angle. Then calculated phase angle was correlated with the coating thickness. The method demonstrated potential in the evaluation of coating thickness and was successfully applied to measure the non-uniform top layers ranging from 0.1 mm to 0.6 mm; within an accuracy of 0.0003-0.0023 mm for PT and 0.0003-0.0067 mm for LIT. The simulation model enabled a better understanding of PT and LIT and provided a means of establishing the required experimental set-up parameters. This also led to optimization of experimental configurations, thus limiting the number of physical tests necessary.

  3. Evaluation of the Shearing Strength of a WC-12Co Thermal Spray Coating by the Scraping Test Method

    Directory of Open Access Journals (Sweden)

    Kenji Kaneko

    2015-07-01

    Full Text Available This paper reports on an experimental and analytical investigation conducted into efficacy of the scraping shear-test method in estimating the shearing adhesive strength of a thermally sprayed coating. It was found that the critical average shear stress, the apparent failure strength of WC-Co thermal spray coating, depends on both the dimensions of the test piece and the loading position around the interface between the coating and the substrate. More specifically, the apparent critical shear stress decreased as the height and width of the test piece increased. In addition, the apparent critical shear stress increased with increasing coating thickness and with decreasing loading point distance measured from the interface. Consequently, the real adhesive strength of thermally sprayed coating could not be ascertained from these experimental results. Furthermore, most of the failure initiation points were inside the coating, as opposed to at the interface. This fact means that the results of the tests do not indicate the interfacial adhesive strength, but rather the shear strength of the coating. Three-dimensional finite element method (FEM analysis showed that the distributions of the shearing stress at the loading points were virtually the same at failure, regardless of the dimensions of the test piece. These results suggest that the scraping test method needs a corresponding numerical analysis of the failure mode in order to produce reliable results and is not necessarily able to estimate the interfacial adhesive strength of thermally sprayed coating.

  4. Evaluation of bone loss in antibacterial coated dental implants: An experimental study in dogs

    DEFF Research Database (Denmark)

    Gallardo, Maria Godoy; Manzanares-Céspedes, Maria Cristina; Sevilla, Pablo

    2016-01-01

    The aim of this study was to evaluate the in vivo effect of antibacterial modified dental implants in the first stages of peri-implantitis. Thirty dental implants were inserted in the mandibular premolar sites of 5 beagle dogs. Sites were randomly assigned to Ti (untreated implants, 10 units), Ti...

  5. Local electrochemical evaluation of a self-healing coating based on encapsulated healing-agent

    NARCIS (Netherlands)

    González-García, Y.; García, S.J.; Fischer, H.R.; Hughes, A.E.; Mol, J.M.C.

    2011-01-01

    In this work local electrochemical techniques are introduced as powerful and complementary techniques for the in-situ evaluation of self-healing systems applied for the protection of metals against corrosion. Scanning vibrating electrode technique (SVET) and scanning electrochemical microscopy

  6. Beam-induced damage on diffractive hard X-ray optics.

    Science.gov (United States)

    Nygård, K; Gorelick, S; Vila-Comamala, J; Färm, E; Bergamaschi, A; Cervellino, A; Gozzo, F; Patterson, B D; Ritala, M; David, C

    2010-11-01

    The issue of beam-induced damage on diffractive hard X-ray optics is addressed. For this purpose a systematic study on the radiation damage induced by a high-power X-ray beam is carried out in both ambient and inert atmospheres. Diffraction gratings fabricated by three different techniques are considered: electroplated Au gratings both with and without the polymer mold, and Ir-coated Si gratings. The beam-induced damage is monitored by X-ray diffraction and evaluated using scanning electron microscopy.

  7. Evaluation of the behavior of shrouded plasma spray coatings in the platen superheater of coal-fired boilers

    Science.gov (United States)

    Sidhu, Buta Singh; Prakash, S.

    2006-06-01

    Nickel- and cobalt-based coatings were formulated by a shrouded plasma spray process on boiler tube steels, namely, ASTM-SA210-grade A1 (GrA1), ASTM-SA213-T-11 (T11), and ASTM-SA213-T-22 (T22). The Ni-22Cr-10Al-1Y alloy powder was sprayed as a bond in each case before the final coating. The degradation behavior of the bared and coated steels was studied in the platen superheater of the coal-fired boiler. The samples were inserted through the soot blower dummy points with the help of stainless steel wires. The coatings were found to be effective in increasing resistance to degradation in the given boiler environment. The maximum protection was observed in the case of Stellite-6 (St-6) coating.

  8. Principles of ESCA and application to metal corrosion, coating and lubrication

    Science.gov (United States)

    Wheeler, D. R.

    1978-01-01

    The principles of ESCA (electron spectroscopy for chemical analysis) were described by comparison with other spectroscopic techniques. The advantages and disadvantages of ESCA as compared to other surface sensitive analytical techniques were evaluated. The use of ESCA was illustrated by actual applications to oxidation of steel and Rene 41, the chemistry of lubricant additives on steel, and the composition of sputter deposited hard coatings. A bibliography of material that was useful for further study of ESCA was presented and commented upon.

  9. Principles of ESCA and applications to metal corrosion, coating and lubrication. [Electron Spectroscopy for Chemical Analysis

    Science.gov (United States)

    Wheeler, D. R.

    1978-01-01

    The principles of ESCA (electron spectroscopy for chemical analysis) are described by comparison with other spectroscopic techniques. The advantages and disadvantages of ESCA as compared to other surface sensitive analytical techniques are evaluated. The use of ESCA is illustrated by actual applications to oxidation of steel and Rene 41, the chemistry of lubricant additives on steel, and the composition of sputter deposited hard coatings. Finally, a bibliography of material that is useful for further study of ESCA is presented and commented upon.

  10. Antibacterial TiO2 Coating Incorporating Silver Nanoparticles by Microarc Oxidation and Ion Implantation

    OpenAIRE

    Peng Zhang; Zhiguo Zhang; Wei Li

    2013-01-01

    Infection associated with titanium implants remains the most common serious complication in hard tissue replacement surgery. Since such postoperative infections are usually difficult to cure, it is critical to find optimal strategies for preventing infections. In this study, TiO2 coating incorporating silver (Ag) nanoparticles were fabricated on pure titanium by microarc oxidation and ion implantation. The antibacterial activity was evaluated by exposing the specimens to Staphylococcus aureus...

  11. Characterization of the wear resistant aluminum oxide - 40% titaniumdioxide coating

    Directory of Open Access Journals (Sweden)

    Mihailo R. Mrdak

    2014-02-01

    Full Text Available Plasma spray coatings play an important role in the design of surface properties of engineering components in order to increase their durability and performance under different operating conditions. Coatings are the most often used for wear resistance. This paper presents the microstructure and mechanical properties Al2O3_­40wt.%TiO2 coating resistant to dry friction slide, grain abrasion and erosion of particles at operating temperatures up to 540°C. In order to obtain the optimal characteristics of coating was performed  optimization  of deposition parameters. The powder Al2O3­40wt.%TiO2 is deposited atmospheric plasma spraying (APS process with a plasma current of 700, 800 and 900A. Evaluate the quality of the coating Al2O3­40wt.%TiO2 were made on the basis of their hardness, tensile bond strength and microstructure. The best performance showed the deposited layers with 900A. The morphology of the powder particles Al2O3­40wt.%TiO2 was examined with SEM (Scanning Electron Microscope. Microstructure of the coatings was examined by light microscopy. Analysis of the deposited layers was performed in accordance with standard Pratt & Whitney. Evaluation of mechanical properties of the layers was done by examining HV0.3 microhardness and tensile strength of the tensile testing. Studies have shown that plasma currents significantly affects the mechanical properties and microstructure of coatings which are of crucial importance for the protection for components subjected to wear       

  12. In vitro and in vivo evaluation of zinc-modified ca-si-based ceramic coating for bone implants.

    Directory of Open Access Journals (Sweden)

    Jiangming Yu

    Full Text Available The host response to calcium silicate ceramic coatings is not always favorable because of their high dissolution rates, leading to high pH within the surrounding physiological environment. Recently, a zinc-incorporated calcium silicate-based ceramic Ca2ZnSi2O7 coating, developed on a Ti-6Al-4V substrate using plasma-spray technology, was found to exhibit improved chemical stability and biocompatibility. This study aimed to investigate and compare the in vitro response of osteoblastic MC3T3-E1 cells cultured on Ca2ZnSi2O7 coating, CaSiO3 coating, and uncoated Ti-6Al-4V titanium control at cellular and molecular level. Our results showed Ca2ZnSi2O7 coating enhanced MC3T3-E1 cell attachment, proliferation, and differentiation compared to CaSiO3 coating and control. In addition, Ca2ZnSi2O7 coating increased mRNA levels of osteoblast-related genes (alkaline phosphatase, procollagen α1(I, osteocalcin, insulin-like growth factor-I (IGF-I, and transforming growth factor-β1 (TGF-β1. The in vivo osteoconductive properties of Ca2ZnSi2O7 coating, compared to CaSiO3 coating and control, was investigated using a rabbit femur defect model. Histological and histomorphometrical analysis demonstrated new bone formation in direct contact with the Ca2ZnSi2O7 coating surface in absence of fibrous tissue and higher bone-implant contact rate (BIC in the Ca2ZnSi2O7 coating group, indicating better biocompatibility and faster osseointegration than CaSiO3 coated and control implants. These results indicate Ca2ZnSi2O7 coated implants have applications in bone tissue regeneration, since they are biocompatible and able to osseointegrate with host bone.

  13. Preparation and Characterization of Plasma Electrolytic Oxidation Coating on 5005 Aluminum Alloy with Red Mud as an Electrolyte Additive

    Science.gov (United States)

    Liu, Shifeng; Zeng, Jianmin; Wang, Youbin

    2017-10-01

    A coating with red mud as an electrolyte additive was applied to 5005 aluminum alloy using plasma electrolytic oxidation (PEO). The phase composition of the coating was investigated using X-ray diffraction. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) was used to determine the microstructure and composition profiles of the coating. The coating/substrate adhesion was determined by scratch testing. The corrosion behaviors of the substrate and coating were evaluated using potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS). The results indicated that the PEO coating with red mud consisted mainly of α-Al2O3 and γ-Al2O3, with small amounts of Fe2O3, CaCO3, and CaTiO3. The surface of the coating was the color of the red mud. The coating had a uniform thickness of about 80 μm and consisted of two main layers: a 6- μm porous outer layer and a 74- μm dense inner layer, which showed typical metallurgical adhesion (coating/substrate adhesion strength of 59 N). The coating hardness was about 1142 HV, much higher than that of the substrate (60 HV). The corrosion potential E corr and corrosion current density i corr of the coating were estimated to be -0.743 V and 3.85 × 10-6 A cm-2 from the PDP curve in 3.5 wt pct NaCl solution, and the maximum impedance and phase angle of the coating were 11 000 Ω and -67 deg, respectively, based on EIS. PEO coating with red mud improved the surface properties and corrosion resistance of 5005 aluminum alloy. This study also shows a potential method for reusing red mud.

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

    Energy Technology Data Exchange (ETDEWEB)

    Sangeetha, S. [Advanced Nanocomposite Coatings Laboratory, Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003 (India); Kalaignan, G. Paruthimal, E-mail: pkalaignan@yahoo.com [Advanced Nanocomposite Coatings Laboratory, Department of Industrial Chemistry, Alagappa University, Karaikudi 630 003 (India); Anthuvan, J. Tennis [M. Kumarasamy College of Engineering, Karur, Tamil Nadu (India)

    2015-12-30

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

  15. In vitro and in vivo evaluation of the surface bioactivity of a calcium phosphate coated magnesium alloy.

    Science.gov (United States)

    Xu, Liping; Pan, Feng; Yu, Guoning; Yang, Lei; Zhang, Erlin; Yang, Ke

    2009-03-01

    Magnesium has shown potential application as a bio-absorbable biomaterial, such as for bone screws and plates. In order to improve the surface bioactivity, a calcium phosphate was coated on a magnesium alloy by a phosphating process (Ca-P coating). The surface characterization showed that a porous and netlike CaHPO(4).2H(2)O layer with small amounts of Mg(2+) and Zn(2+) was formed on the surface of the Mg alloy. Cells L929 showed significantly good adherence and significantly high growth rate and proliferation characteristics on the Ca-P coated magnesium alloy (p<0.05) in in-vitro cell experiments, demonstrating that the surface cytocompatibility of magnesium was significantly improved by the Ca-P coating. In vivo implantations of the Ca-P coated and the naked alloy rods were carried out to investigate the bone response at the early stage. Both routine pathological examination and immunohistochemical analysis demonstrated that the Ca-P coating provided magnesium with a significantly good surface bioactivity (p<0.05) and promoted early bone growth at the implant/bone interface. It was suggested that the Ca-P coating might be an effective method to improve the surface bioactivity of magnesium alloy.

  16. Evaluation of nano ceramic coating on radiographic defects of thin-walled AL4-4 aluminum alloy sand casting

    Directory of Open Access Journals (Sweden)

    Mansour Borouni

    2016-10-01

    Full Text Available Internal defects are among the problems in gravity casting of aluminum parts. The main internal volumetric defects are gas and shrinkage defects which form during solidification of the melt and drastically reduce the quality of the produced parts. These defects adversely affect the mechanical properties of thin walled castings parts. In this study, ceramic nanoparticles coatings were applied on the sand mold and the effect of mold coatings on the reduction of defects were investigated. X-ray radiography was used to detect defects in sand molds with ceramic nanoparticles coatings. For comparison, this test was performed on molds with micro-ceramic and graffiti coatings and uncoated sand mold. The results showed that the maximum amount of gas and shrinkage defects was observed in casting parts from AL4-1 alloy in uncoated molds. On the other hand, the minimum defects were found in molds coated with ceramic nanoparticles. It seems that the reduced defects in casting parts in molds coated with ceramic nanoparticles may be due to high thermal and chemical stability and higher heat transfer rate of the coating. These results can facilitate the production of high quality aluminum alloys parts using nanotechnology.

  17. Tantalum coating on porous Ti6Al4V scaffold using chemical vapor deposition and preliminary biological evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiang, E-mail: xiangliwj@sjtu.edu.cn [School of Mechanical Engineering, Shanghai Jiao Tong University, State Key Laboratory of Mechanical System and Vibration, Shanghai, 200240 (China); Wang, Lin [Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi' an, 710032 (China); Yu, Xiaoming [The Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016 (China); Feng, Yafei [Institute of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi' an, 710032 (China); Wang, Chengtao [School of Mechanical Engineering, Shanghai Jiao Tong University, State Key Laboratory of Mechanical System and Vibration, Shanghai, 200240 (China); Yang, Ke [The Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110016 (China); Su, Daniel [School of Mechanical Engineering, Shanghai Jiao Tong University, State Key Laboratory of Mechanical System and Vibration, Shanghai, 200240 (China)

    2013-07-01

    Porous tantalum (Ta), produced via chemical vapor deposition (CVD) of commercially pure Ta onto a vitreous carbon, is currently available for use in orthopedic applications. However, the relatively high manufacturing cost and the incapability to produce customized implant using medical image data have limited its application to gain widespread acceptance. In this study, Ta film was deposited on porous Ti6Al4V scaffolds using CVD technique. Digital microscopy and scanning electron microscopy indicated that the Ta coating evenly covered the entire scaffold structure. X-ray diffraction analysis showed that the coating consisted of α and β phases of Ta. Goat mesenchymal stem cells were seeded and cultured on the Ti6Al4V scaffolds with and without coating. The tetrazolium-based colorimetric assay exhibited better cell adhesion and proliferation on Ta-coated scaffolds compared with uncoated scaffolds. The porous scaffolds were subsequently implanted in goats for 12 weeks. Histological analysis revealed similar bone formation around the periphery of the coated and uncoated implants, but bone ingrowth is better within the Ta-coated scaffolds. To demonstrate the ability of producing custom implant for clinical applications via this technology, we designed and fabricated a porous Ti6Al4V scaffold with segmental mandibular shape derived from patient computerized tomography data. - Highlights: • Ta film was coated on porous Ti6Al4V scaffold using chemical vapor deposition. • Tantalum coating allowed for higher levels of cell adhesion and proliferation. • Better new bone formation occurred inside the tantalum-coated scaffolds. • Clinical image data was integrated with EBM to fabricate customized scaffold.

  18. In vitro and in vivo evaluations on osteogenesis and biodegradability of a β-tricalcium phosphate coated magnesium alloy.

    Science.gov (United States)

    Chai, Hongwei; Guo, Lei; Wang, Xiantao; Gao, Xiaoyu; Liu, Kui; Fu, Yuping; Guan, Junlin; Tan, Lili; Yang, Ke

    2012-02-01

    Magnesium (Mg) alloys have been demonstrated to be potential orthopedic implants due to their biodegradability in vivo. To enhance its corrosion resistance and improve its osteogenesis, β-tricalcium phosphate (β-TCP) was coated on a Mg alloy (Mg-3AI-1Zn) by phosphating process. In vitro, the human osteosarcoma cell line (SaOS-2) showed significantly good adherence and proliferation on the surface of the β-TCP coated Mg alloy after 24-h incubation. The growth factor bone morphogenetic protein 2 (BMP-2) was highly expressed in SaOS-2 cultured with the β-TCP coated Mg alloy by Western blot analysis (p < 0.05). In vivo, the newborn bone at the implant/bone interface was formed at week 1 and matured at week 4 postimplantation. Villous tissue was found at the implant/bone interface at week 12 postimplantation. The contents of phosphorus and calcium on the surface of the β-TCP coated Mg alloy were decreased at week 4 and week 12 postimplantation, respectively. Immunohistochemical analysis of the experiment results demonstrated that the β-TCP coated Mg alloy implants provided a high BMP-2 expression during the first 4 weeks postimplantation. Compared with the naked Mg alloy which was degraded for 33% in vivo, only 17% of the β-TCP coated Mg alloy was degraded at week 12 postimplantation (p < 0.05). The in vitro cell tests showed that the β-TCP coating provided the Mg alloy with a significantly better surface cytocompatibility, and in vivo results also confirmed that the β-TCP coating exhibited greatly improved osteoconductivity and osteogenesis in the early 12 weeks postoperation period. Moreover, in vivo experiment demonstrated that the β-TCP coating layer could slow down the degradation of the naked Mg alloy at the early stage of implantation. Copyright © 2011 Wiley Periodicals, Inc.

  19. Influence of salivary washout on drug delivery to the oral cavity using coated microneedles: An in vitro evaluation.

    Science.gov (United States)

    Serpe, Luciano; Jain, Amit; de Macedo, Cristina Gomes; Volpato, Maria Cristina; Groppo, Francisco Carlos; Gill, Harvinder Singh; Franz-Montan, Michelle

    2016-10-10

    The objective of this study was to determine whether in buccal tissues, after insertion and removal of coated microneedles, the presence of saliva over the insertion site can lead to loss of the deposited drug, and if saliva can influence in vitro permeation of the drug across the tissue. Microneedles were coated with sulforhodamine (SRD), which was used as a model drug, and inserted in to porcine buccal mucosa in vitro. Fluorescence microscopy was used to study microneedle coating quality and the diffusion of SRD through the mucosa. Permeation experiments were conducted for simulated dynamic or static salivary