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Sample records for polished molybdenum surface

  1. Surface layer softing in mechanically polished molybdenum monocrystals

    International Nuclear Information System (INIS)

    Ivashchenko, R.K.; Kostyuchenko, V.G.; Lotsko, D.V.; Lukinov, I.V.; Mil'man, Yu.V.; Novikov, G.A.

    1990-01-01

    Softening of the surface layer together with growth of dislocation density is found in molybdenum single crystals mechanically polished with diamond suspension in water solution of CuSO 4 . The penetration of small amount of copper into molybdenum is observed by SIMS. A supposition has been made about molybdenum solid solution softening influenced by copper penetrating into molybdenum by means of a dynamic dislocation mechanism

  2. Relation between the optical and metallurgical properties of polished molybdenum mirrors

    Science.gov (United States)

    Bennett, J. M.; Wong, S. M.; Krauss, G.

    1980-10-01

    A study has been performed to determine the correlation among the microstructure, metallurgical processing, and optical surface finish of commercially available types of molybdenum (Mo) bar and plate and 0.5-mm thick Mo sheet. Specimens of bar and plate stock produced from low-carbon vacuum-arc Mo or powder-metallurgy-processed Mo, as well as TZM(Ti-Zr-Mo) Mo alloy, were in the form of 3.86-cm diam disks. In addition, typical cross-rolled sheet specimens were produced from powder-metallurgy-processed Mo that had a very fine grain structure and a high degree of texture. Specimens were extensively characterized both optically and metallurgically. It was found that well-polished surfaces have surface topographies directly related to the microstructure and hence to the processing of the material. In sheet material having a well-developed texture, the polishability appeared to be independent of texture, and the grain size did not result in a lower scatter surface. It was concluded that the optimum type of Mo to use for smooth low-scatter mirrors is low-carbon vacuum-arc-cast plate or sheet material.

  3. In vivo evaluation of defined polished titanium surfaces to prevent soft tissue adhesion.

    Science.gov (United States)

    Hayes, Jessica S; Welton, Joanne L; Wieling, Ronald; Richards, R Geoff

    2012-04-01

    Soft tissue-implant adhesion is often required for implant integration into the body; however, in some situations, the tissue is required to glide freely over an implant. In the case of distal radius fracture treatment, current literature describes how titanium and its alloys tend to lead to more intra-tendon inflammatory reactions compared with stainless steel. This leads to tendon-implant adhesion and damage possibly causing limited palmar flexion and even tendon rupture. The goal of this study was to analyze the effect of different surface polishings of titanium and titanium molybdenum implants on soft tissue reactions in vivo, with the aim to prevent direct soft tissue adhesion. Using a nonfracture model, to allow for study of the soft-tissue-implant surface interactions only, six surface variants of the same plate design were implanted onto the tibia of 24 New Zealand white rabbits and left in situ for 12 weeks. Results indicate that paste polished commercially pure titanium and titanium molybdenum alloy had the least soft tissue adhesion, with the concomitant development of a soft tissue capsule. Surface topography did not appear influence the thickness of the connective tissue surrounding the plate. Therefore, suitable surface polishing could be applied to plates for clinical use, where free gliding of tissues is required. Copyright © 2012 Wiley Periodicals, Inc.

  4. Directional uv photoemission from (100) and (110) molybdenum surfaces

    DEFF Research Database (Denmark)

    Cinti, R. C.; Khoury, E. Al; Chakraverty, B. K.

    1976-01-01

    A study of the (100) and (110) molybdenum surfaces by directional photoemission spectroscopy is presented. Energy distribution spectra formed by photoelectrons emitted normal to the surfaces have been measured for photon energies between 10.2 and 21.2 eV. The results are discussed in terms...

  5. Surface Roughness and Gloss of Actual Composites as Polished With Different Polishing Systems.

    Science.gov (United States)

    Rodrigues-Junior, S A; Chemin, P; Piaia, P P; Ferracane, J L

    2015-01-01

    This in vitro study evaluated the effect of polishing with different polishing systems on the surface roughness and gloss of commercial composites. One hundred disk-shaped specimens (10 mm in diameter × 2 mm thick) were made with Filtek P-90, Filtek Z350 XT, Opallis, and Grandio. The specimens were manually finished with #400 sandpaper and polished by a single operator using three multistep systems (Superfix, Diamond Pro, and Sof-lex), one two-step system (Polidores DFL), and one one-step system (Enhance), following the manufacturer's instructions. The average surface roughness (μm) was measured with a surface profilometer (TR 200 Surface Roughness Tester), and gloss was measured using a small-area glossmeter (Novo-Curve, Rhopoint Instrumentation, East Sussex, UK). Data were analyzed by two-way analysis of variance and Tukey's test (α=0.05). Statistically significant differences in surface roughness were identified by varying the polishing systems (pGrandio when polished with Sof-Lex and Filtek Z250 and Opallis when polished with Enhance. Gloss was influenced by the composites (p<0.0001), the polishing systems (p<0.0001), and the interaction between them (p<0.0001). The one-step system, Enhance, produced the lowest gloss for all composites. Surface roughness and gloss were affected by composites and polishing systems. The interaction between both also influenced these surface characteristics, meaning that a single polishing system will not behave similarly for all composites. The multistep systems produced higher gloss, while the one-step system produced the highest surface roughness and the lowest gloss of all.

  6. Tribological approach to study polishing of road surface under traffic

    OpenAIRE

    KANE, Malal; DO, Minh Tan

    2007-01-01

    The polishing phenomenon of road pavements under the vehicle traffic constitutes the main mechanism inherent to the loss of skid resistance over time. A better understanding of this phenomenon would allow an improvement of road safety. This study comprises a review of laboratory test and a model simulating the polishing of road surfaces. The laboratory test uses a polishing machine so called 'Wehner-Schulze' which can reproduce the evolution of the road texture from specimens taken directly f...

  7. Femtosecond laser surface structuring of molybdenum thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kotsedi, L., E-mail: Kotsedi@tlabs.ac.za [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); Mthunzi, P. [Council for Scientific and Industrial Research (CSIR), Biophotonics Lab: National Laser Centre Pretoria, 0001 (South Africa); Nuru, Z.Y. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); Eaton, S.M. [Physics Department, Politecnico di Milano, Piazza Leonardo Da Vinci, 32, 20133 Milano (Italy); Center for Nano Science and Technology, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Itala (Italy); Sechoghela, P.; Mongwaketsi, N. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa); Ramponi, R. [Institute for Photonics and Nanotechnologies (IFN)–CNR, Piazza Leanardo Da Vinci, 32, 20133 Milano (Italy); Maaza, M. [UNESCO-UNISA Africa Chair in Nanosciences-Nanotechnology, College of Graduate Studies, University of South Africa, Muckleneuk ridge, PO Box 392, Pretoria (South Africa); Nanosciences African Network (NANOAFNET), iThemba LABS-National Research Foundation, 1 Old Faure Road, Somerset West 7129, PO Box 722, Somerset West, Western Cape Province (South Africa)

    2015-10-30

    Highlights: • Color change of the molybdenum thin film from shinny to violet–yellowish color after laser irradiation at various laser powers. • Formation of the molybdenum dioxide coating after laser exposure, as confirmed by the X-ray diffraction spectrometry. • Selective solar absorbing nature of the laser exposed films. • Study of the binding energies is presented in this contribution using the XPS spectrometry. - Abstract: This contribution reports on the femtosecond surface structuring of molybdenum thin coatings deposited by electron beam evaporation onto Corning glass substrates. The 1-D type periodic grating lines created by such an ablation showed that the widths of the shallow grooves followed a logarithmic dependence with the laser energy incident on the molybdenum film. The electronic valence “x” of the created oxide surface layer MoO{sub x} was found to be incident laser power dependent via Rutherford backscattering spectrometry, X-ray photoelectron spectroscopy and X-ray diffraction investigations. Such a photo-induced MoO{sub x}–Mo nanocomposite exhibited effective selective solar absorption in the UV–vis–IR spectral range.

  8. Profilometric analysis of root surfaces after using various polishing agents

    Directory of Open Access Journals (Sweden)

    Anjan Jana

    2016-01-01

    Full Text Available Background: Polishing is an important step in oral prophylaxis procedure which retards further accumulation of plaque on the root surfaces. Though polishing was done with various abrasive particles with different sizes over a long period of time, it was never been highlighted to evaluate the ideal polishing material and the particle size that would produce the ideal surface smoothness (Ra 5 μm are not able to produce the surface smoothness <0.2 μm. Only, submicron sized particles are able to produce the desired smoothness.

  9. Factors influencing the surface quality of polished tool steels

    International Nuclear Information System (INIS)

    Rebeggiani, S; Rosén, B-G

    2014-01-01

    Today’s demands on surface quality of moulds for injection moulding of plastic components involve no/low defect contents and roughness levels in the nm-range for high gloss applications. Material properties as well as operating conditions influence the mould finish, and thus the final surface of moulded products. This paper focuses on how particle content and different polishing strategies influence final surface qualities of moulds. Visual estimations of polished tool steel samples were combined with non-contact 3D-surface texture analysis in order to correlate traditional assessments to more quantitative methods, and to be able to analyse the surfaces at nanometre-level. It was found that steels with a lower proportion of particles, like carbides and oxides, gave rise to smoother polished surfaces. In a comparative study of polishers from different polishing shops, it was found that while different surface preparation strategies can lead to similar final roughness, similar preparation techniques can produce high-quality surfaces from different steel grades. However, the non-contact 3D-surface texture analysis showed that not all smooth polished surfaces have desirable functional topographies for injection moulding of glossy plastic components. (paper)

  10. Laser polishing for topography management of accelerator cavity surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Liang [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Klopf, J. Mike [College of William and Mary, Williamsburg, VA (United States); Reece, Charles E. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Kelley, Michael J. [College of William and Mary, Williamsburg, VA (United States); Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2015-07-20

    Improved energy efficiency and reduced cost are greatly desired for advanced particle accelerators. Progress toward both can be made by atomically-smoothing the interior surface of the niobium superconducting radiofrequency accelerator cavities at the machine's heart. Laser polishing offers a green alternative to the present aggressive chemical processes. We found parameters suitable for polishing niobium in all surface states expected for cavity production. As a result, careful measurement of the resulting surface chemistry revealed a modest thinning of the surface oxide layer, but no contamination.

  11. Advanced surface polishing using gas cluster ion beams

    Science.gov (United States)

    Insepov, Z.; Hassanein, A.; Norem, J.; Swenson, D. R.

    2007-08-01

    The gas cluster ion beam (GCIB) treatment can be an important treatment for mitigation of the Q-slope in superconducting cavities. The existing surface smoothening methods were analyzed and a new surface polishing method was proposed based on employing extra-large gas cluster ions (X-GCIB).

  12. Effect of Polishing Systems on Surface Roughness and Topography of Monolithic Zirconia.

    Science.gov (United States)

    Goo, C L; Yap, Auj; Tan, Kbc; Fawzy, A S

    2016-01-01

    This study evaluated the effect of different chairside polishing systems on the surface roughness and topography of monolithic zirconia. Thirty-five monolithic zirconia specimens (Lava PLUS, 3M ESPE) were fabricated and divided into five groups of seven and polished with the following: Group 1 (WZ)-Dura white stone followed by Shofu zirconia polishing kit; Group 2 (SZ)-Shofu zirconia polishing kit; Group 3 (CE)-Ceramiste porcelain polishers; Group 4 (CM)-Ceramaster porcelain polishers; and Group 5 (KZ)-Komet ZR zirconia polishers. All specimens were ground with a fine-grit diamond bur prior to polishing procedures to simulate clinical finishing. Baseline and post-polishing profilometric readings were recorded and delta Ra values (difference in mean surface roughness before and after polishing) were computed and analyzed using one-way analysis of variance and Scheffe post hoc test (pzirconia.

  13. Specular and non-specular X-ray reflection from a single-crystal molybdenum mirror surface

    CERN Document Server

    Mizusawa, M

    2003-01-01

    The surface morphology of a super-polished mirror of single-crystal molybdenum has been studied by grazing-incidence X-ray reflection. It yields a rather high specular reflectivity (82.0%) for 16.0 keV X-rays below the critical angle. The data suggest that the mirror has a small roughness (0.7 nm rms) unlike other metal mirrors, but, on the other hand, strongly damaged layers (6.35 nm in total) exist at the near surface. It has been also found that the surface has a large correlation length (>3 mu m) and a small Hurst parameter (0.2-0.3) from the non-specular reflection.

  14. Figuring and Polishing Precision Optical Surfaces Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The requirements for cost effective manufacturing and metrology of large optical surfaces is instrumental for the success of future NASA programs such as LISA,...

  15. Mirror surface metrology and polishing for AXAF/TMA

    International Nuclear Information System (INIS)

    Slomba, A.; Babish, R.; Glenn, P.

    1985-01-01

    The achievement of the derived goals for mirror surface quality on the Advanced X-ray Astrophysics Facility (AXAF), Technology Mirror Assembly (TMA) required a combination of state-of-the-art metrology and polishing techniques. In this paper, the authors summarize the derived goals and cover the main facets of the various metrology instruments employed, as well as the philosophy and technique used in the polishing work. In addition, they show how progress was measured against the goals, using the detailed error budget for surface errors and a mathematical model for performance prediction. The metrology instruments represented a considerable advance on the state-of-the-art and fully satisfied the error budget goals for the various surface errors. They were capable of measuring the surface errors over a large range of spatial periods, from low-frequency figure errors to microroughness. The polishing was accomplished with a computer-controlled process, guided by the combined data from various metrology instruments. This process was also tailored to reduce the surface errors over the full range of spatial periods

  16. Study on the influence of the rotational speed of polishing disk on material removal in aspheric surface compliant polishing

    Directory of Open Access Journals (Sweden)

    Liyong Hu

    2015-03-01

    Full Text Available When a soft polishing tool is compressed on a stiff workpiece of curved surface, the contact area is a piece of the curved surface. In the process of aspheric surface polishing, the machining speed is always provided by the rotational speed of the spindle of a computer numerical control lathe. Yet, the polishing tool is usually made rotating to remove cutting scraps and broken abrasives from the contact area. The rotational speed of the polishing tool would change the distribution state of the relative speed in the whole contact area, and it would definitely change the volume of material removal in the surface of the workpiece. This article studies how the rotational speed of the polishing tool changes the distribution state of the relative speed in the whole contact area and material removal in the volume of the surface of the workpiece. The computing results show that the volume of material removal increases with the increase in both the rotational speed of polishing disk and the rotational speed of lathe spindle, but the polishing quality is totally not in this case.

  17. The determination of oxygen in molybdenum and tungsten monocrystals taking into account the surface oxygen contribution

    International Nuclear Information System (INIS)

    Aleksandrov, V.D.; Egiazarov, B.G.; Polyakova, I.S.; Sel'dyakov, Yu.P.; Chernyavskij, V.T.

    1977-01-01

    The method has been developed for determining oxygen content in molybdenum and tungsten usign the neutron activation analysis. The sensitivity is 1.6X10 -5 and 1.3x10 -3 wt.% for molybdenum and tungsten, respectively. The density of oxygen distribution in surface layers has been experimentally evaluated. It is shown that the oxygen presence in a surface layer of molybdenum and tungsten does not impede oxygen determination in the bulk of the sample, when the oxygen content is >5x10 -5 wt.%. If oxygen content is -3 wt.%, the presence of oxygen in the surface layer should be taken into account

  18. Influence of polishing on surface roughness following toothbrushing wear of composite resins.

    Science.gov (United States)

    Dalla-Vecchia, Karine Battestin; Taborda, Talita Damas; Stona, Deborah; Pressi, Heloísa; Burnett Júnior, Luiz Henrique; Rodrigues-Junior, Sinval Adalberto

    2017-01-01

    This study aimed to evaluate the influence of different polishing systems on the surface roughness of composite resins following procedures to simulate the effects of toothbrushing over time. Four currently available commercial composites were used to make 128 cylindrical specimens. The specimens were randomly allocated to polishing with a 1-step polisher or 1 of 3 multistep polishers (n = 8 per group). The baseline surface roughness was measured, and the specimens were submitted to 5000, 10,000, and 20,000 brushing cycles to represent toothbrushing throughout 6, 12, and 24 months, respectively. Results showed that surface roughness was influenced by the type of composite and polishing system and was not influenced by the simulated toothbrushing time. However, the surface roughness, as challenged by toothbrushing wear, was affected by the interaction among the composite, the polisher, and the toothbrushing time. The 1-step polisher produced the highest surface roughness and influenced toothbrushing wear resistance of some composites.

  19. Surface roughness and morphology of three nanocomposites after two different polishing treatments by a multitechnique approach.

    Science.gov (United States)

    Janus, J; Fauxpoint, G; Arntz, Y; Pelletier, H; Etienne, O

    2010-05-01

    The purpose of this study was to assess the surface roughness and morphology of three nanocomposites polished with two different polishing systems. Specimens made of hybrid composite (Tetric Ceram [TC] as control) and nanocomposites: nanofilled (Filtek Supreme [FS]), nanofilled hybrid (Grandio [Gr]), complex nanofilled hybrid (Synergy D6 [Syn]) were polished with CompoSystem [CS] or Sof-Lex [SL] polishing discs. The average surface roughness (Ra) before and after polishing was measured using optical profilometry. Both AFM and SEM techniques were additionally used to analyze the surface morphology after polishing with the aim of relating the surface morphology and the surface roughness. Statistical analysis was done by ANOVA using a general linear model (alpha=0.05) with an adjustment for multiple comparisons. Within the same polishing system, FS exhibited the smoothest surface, followed by Syn, TC and Gr (p<0.0001). Sof-Lex polishing discs produced the smoothest surface compared to CompoSystem (p<0.0001). AFM and SEM observations confirmed that the surface roughness was related to the surface morphology and to the average filler size. Positive correlation between the average filler size and the surface roughness suggest that using nanoparticles in the formulation does not necessary improve the surface texture. The nanofilled composite FS, which contains only nanofillers, showed the best results when associated to Sof-Lex polishing discs. 2010 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

  20. Effect of various polishing systems on the surface roughness and phase transformation of zirconia and the durability of the polishing systems.

    Science.gov (United States)

    Park, Chan; Vang, Mong-Sook; Park, Sang-Won; Lim, Hyun-Pil

    2017-03-01

    Although many systems are used to polish zirconia, a comparison of the performance of zirconia and feldspathic porcelain polishing systems is lacking. The purpose of this in vitro study was to compare the effects of 3 polishing systems on surface roughness, zirconia phase transformation, and durability of the polishing systems when applied to zirconia and feldspathic porcelain. Three polishing systems were evaluated: Z1, a zirconia polishing system; Z2, a zirconia polishing system, and F1, a feldspathic porcelain polishing system. Three ceramic systems were evaluated: PR and ZM zirconia specimens (diameter 15 mm, height 2 mm; 23 specimens each) and CB feldspathic porcelain specimens of the same size (15 specimens). A rough surface was created on the 3 types of specimens (15 specimens each) to model an occlusal adjustment under the same conditions. Polishing was carried out with the 3 polishing systems for 2 minutes each. Surface roughness was measured with a 3-dimensional (3D) optical profiler. The surface was also observed with a scanning electron microscopy. X-ray diffraction analysis was performed for 8 PR or ZM zirconia specimens polished by using the Z1 and Z2 systems for 8 minutes to evaluate the phase transformation of zirconia before, during, and after polishing. These specimens were compared and analyzed for phase transformation that might have occurred during the polishing of the specimens. After finishing the surface roughness experiment and the phase transformation experiment, the volumes of the polishers were measured with a 3D volume scanner and compared with those before the experiments to evaluate the durability of the polishing system. A statistical analysis of all data was performed using 2-way ANOVA and the Tukey honest significant difference test (α=.05). The 2 zirconia polishing systems (Z1, Z2) created a significantly (Pzirconia specimens for 8 minutes, the maximum percentages of monoclinic phase increased by 0.03% in the Z1 system and by 0

  1. Efficacy of polishing kits on the surface roughness and color stability ...

    African Journals Online (AJOL)

    Objective: Different polishing kits may have different effects on the composite resin surfaces. The aim of this study was to evaluate the surface roughness and color stability of four different composites which was applied different polishing technique. Materials and Methods: Thirty specimens were made for each composite ...

  2. Surface changes of metal alloys and high-strength ceramics after ultrasonic scaling and intraoral polishing.

    Science.gov (United States)

    Yoon, Hyung-In; Noh, Hyo-Mi; Park, Eun-Jin

    2017-06-01

    This study was to evaluate the effect of repeated ultrasonic scaling and surface polishing with intraoral polishing kits on the surface roughness of three different restorative materials. A total of 15 identical discs were fabricated with three different materials. The ultrasonic scaling was conducted for 20 seconds on the test surfaces. Subsequently, a multi-step polishing with recommended intraoral polishing kit was performed for 30 seconds. The 3D profiler and scanning electron microscopy were used to investigate surface integrity before scaling (pristine), after scaling, and after surface polishing for each material. Non-parametric Friedman and Wilcoxon signed rank sum tests were employed to statistically evaluate surface roughness changes of the pristine, scaled, and polished specimens. The level of significance was set at 0.05. Surface roughness values before scaling (pristine), after scaling, and polishing of the metal alloys were 3.02±0.34 µm, 2.44±0.72 µm, and 3.49±0.72 µm, respectively. Surface roughness of lithium disilicate increased from 2.35±1.05 µm (pristine) to 28.54±9.64 µm (scaling), and further increased after polishing (56.66±9.12 µm, P scaling (from 1.65±0.42 µm to 101.37±18.75 µm), while its surface roughness decreased after polishing (29.57±18.86 µm, P scaling significantly changed the surface integrities of lithium disilicate and zirconia. Surface polishing with multi-step intraoral kit after repeated scaling was only effective for the zirconia, while it was not for lithium disilicate.

  3. Effects of Polishing Bur Application Force and Reuse on Sintered Zirconia Surface Topography.

    Science.gov (United States)

    Fischer, N G; Tsujimoto, A; Baruth, A G

    2018-03-16

    Limited information is available on how to polish and finish zirconia surfaces following computer-aided design/computer-aided manufacturing (CAD/CAM), specifically, how differing application forces and reuse of zirconia polishing systems affect zirconia topography. To determine the effect of differing, clinically relevant, polishing application forces and multiple usages of polishing burs on the surface topography of CAD/CAM zirconia. One hundred twenty 220-grit carbide finished zirconia disks were sintered according to manufacturer's directions and divided into two groups for the study of two coarse polishing bur types. Each group was divided into subgroups for polishing (15,000 rpm) at 15 seconds for 1.0 N, 4.5 N, or 11 N of force using a purpose-built fixture. Subgroups were further divided to study the effects of polishing for the first, fifth, 15th, and 30th bur use, simulating clinical procedures. Unpolished surfaces served as a control group. Surfaces were imaged with noncontact optical profilometry (OP) and atomic force microscopy (AFM) to measure average roughness values (Ra). Polishing burs were optically examined for wear. Scanning electron microscopy (SEM) was performed on burs and zirconia surfaces. One-way ANOVA with post hoc Tukey HSD (honest significant difference) tests (α=0.05) were used for statistical analyses. AFM and OP Ra values of all polished surfaces were significantly lower than those of the unpolished control. Different polishing forces and bur reuse showed no significant differences in AFM Ra. However, significant differences in OP Ra were found due to differing application forces and bur reuse between the first and subsequent uses. SEM and optical micrographs revealed notable bur wear, increasing with increasing reuse. SEM and AFM micrographs clearly showed polished, periodic zirconia surfaces. Nanoscale topography, as analyzed with kurtosis and average groove depth, was found dependent on the specific polishing bur type. These in

  4. In situ plasma sputtering and angular distribution measurements for structured molybdenum surfaces

    Science.gov (United States)

    Li, Gary Z.; Matlock, Taylor S.; Goebel, Dan M.; Dodson, Christopher A.; Matthes, Christopher S. R.; Ghoniem, Nasr M.; E Wirz, Richard

    2017-06-01

    We present in situ sputtering yield measurements of the time-dependent erosion of flat and micro-architectured molybdenum samples in a plasma environment. The measurements are performed using the plasma interactions (Pi) Facility at UCLA, which focuses a magnetized hollow cathode plasma to a material target with an exposure diameter of approximately 1.5 cm. During plasma exposure, a scanning quartz crystal microbalance (QCM) provides angular sputtering profiles that are integrated to estimate the total sputtering yield. This technique is validated to within the scatter of previous experimental data for a planar molybdenum target exposed to argon ion energies from 100 to 300 eV. The QCM is then used to obtain in situ measurements during a 17 h exposure of a micro-architectured-surface molybdenum sample to 300 eV incident argon ions. The time-dependent angular sputtering profile is shown to deviate from classical planar profiles, demonstrating the unique temporal and spatial sputtering effects of micro-architectured materials. Notably, the sputtering yield for the micro-architectured sample is initially much less than that for planar molybdenum, but then gradually asymptotes to the value for planar molybdenum after approximately 10 h as the surface features are eroded away.

  5. Research on Laser Micro Polishing of SLS Technology Sintered Iron-Based Powder Surface

    OpenAIRE

    Gerda Vaitkūnaitė; Vladislav Markovič; Olegas Černašėjus

    2015-01-01

    The article analyzes laser micro polishing of 1.2083 steel samples produced applying selective laser sintering (SLS) method. The study has evaluated the distribution of the shape, size and temperature of the laser beam treated area in the surface layer of sintered and laser polished samples. Experimental tests have shown the impact of the technical parameters of laser micro polishing on the width and hardness of the impact zone of the treated sample. The microstructure analysis of laser treat...

  6. Simulation and analysis of an alternative kinematics for improving the polishing uniformity over the surface of polished tiles

    Directory of Open Access Journals (Sweden)

    Weingaertner, W. L.

    2010-10-01

    Full Text Available The present work investigates the possibility of adopting a new kinematics at the industrial polishing lines of porcelain stoneware tile. An alternative motion of the transverse oscillation of the polishing heads is proposed, in which no radical changes in the industries facilities are required. The basic idea is to replace the purely sinus motion of the polishing heads by a rather trapezoid wavelike motion. In theory this could be achieved simply by adopting regular delays at the transverse oscillation motion. Consequences of this alternative kinematics were quantitatively analyzed considering the spatial homogeneity of polishing expected for tiles. Such homogeneity was represented by the coefficient of variation of the distribution of polishing time over the surface, which was in turn determined by means of computational simulations, taking into account the effect of multiple polishing heads.

    El presente trabajo investiga la posibilidad de adoptar una nueva cinemática en las líneas de pulido industrial de baldosas de gres porcelánico. Se propone una propuesta alternativa de la oscilación transversal de los cabezales pulidores, en el que no hay cambios radicales en las instalaciones de las industrias son necesarias. La idea básica consiste en sustituir el movimiento totalmente del seno de los cabezales pulidores por un movimiento ondulatorio trapezoide. En teoría, esto podría lograrse sólo mediante la adopción de los habituales retrasos en el movimiento de oscilación transversal. las consecuencias de esta cinemática fueron analizados cuantitativamente, teniendo en cuenta la homogeneidad espacial de pulido. Tal homogeneidad fora representada por el coeficiente de variación de la distribución de lo tiempo de pulido en la superficie, determinada por medio de simulaciones computacionales, teniendo también en cuenta el efecto de pulido de las cabezas múltiples.

  7. Effects of Wet and Dry Finishing and Polishing on Surface Roughness and Microhardness of Composite Resins

    Directory of Open Access Journals (Sweden)

    Negin Nasoohi

    2017-08-01

    Full Text Available Objectives: This study aimed to assess the effect of wet and dry finishing and polishing on microhardness and roughness of microhybrid and nanohybrid composites.Materials and Methods: Thirty samples were fabricated of each of the Polofil Supra and Aelite Aesthetic All-Purpose Body microhybrid and Grandio and Aelite Aesthetic Enamel nanohybrid composite resins. Each group (n=30 was divided into three subgroups of D, W and C (n=10. Finishing and polishing were performed dry in group D and under water coolant in group W. Group C served as the control group and did not receive finishing and polishing. Surface roughness of samples was measured by a profilometer and their hardness was measured by a Vickers hardness tester. Data were analyzed using two-way ANOVA (P<0.05.Results: The smoothest surfaces with the lowest microhardness were obtained under Mylar strip without finishing/polishing for all composites (P<0.0001. The highest surface roughness was recorded for dry finishing/polishing for all composites (P<0.0001. Dry finishing/polishing increased the microhardness of all composites (P<0.0001.Conclusions: Dry finishing and polishing increases the microhardness and surface roughness of microhybrid and nanohybrid composite resins. Keywords: Composite Resins; Dental Polishing; Hardness

  8. Effect of finishing/polishing techniques and time on surface roughness of esthetic restorative materials

    Directory of Open Access Journals (Sweden)

    Prashanthi Sampath Madhyastha

    2017-01-01

    Conclusion: It might be concluded that: (i Filtek P90 showed least Ra values followed by < Z100 < Dyract < GIC; (ii immediate (24 h finishing/polishing of materials is better than delayed; and (iii among all these polishing systems, diamond bur–Astropol and Astrobrush showed good surface finish.

  9. Wear and roughness of the metal surface at polishing by bound abrasive

    International Nuclear Information System (INIS)

    Spasskij, M.R.; Lokhov, Yu.N.; Ashkerov, Yu.V.

    1987-01-01

    The model is proposed of the process of polishing of plastic metals by a resin polisher with the surface-saturated layer of abrasive. The model is based on the idea about a net independent effect of individual grains on the metal surface. A linear dependence of the wear rate on the applied pressure is substantiated. It is shown that a determining characteristic of metal in the process of polishing is elastic modulus rather than hardness or yield point. The dependence of a maximally attainable roughness of the metal surface on its plasticity, pressure, concentration and dimension of the abrasive is found

  10. Surface analysis of polished fused-silica laser lenses by ion-scattering spectrometry

    International Nuclear Information System (INIS)

    Orvek, K.; Steward, S.A.

    1982-01-01

    New advances in high-powered glass lasers, particularly the NOVA system, have resulted in a need for lenses having higher damage threshold values than those now available. It is currently thought that surface contaminants on the lenses are responsible for initiating part of the damage. These contaminants are apparently introduced during the final polishing stages. In this study, we used ion-scattering spectrometry (ISS) to identify contaminants arising through the use of different polishing techniques. Five lenses were studied, each having undergone different polishing procedures. The first lens was not polished after receiving it from the manfacturer (No. 381). Ion microprobe data were available for this lens, and they were compared to ISS results. The second lens had been polished with rouge, a polishing compound no longer in use (No. 796). This sample served as a further check on the ISS results. The third lens was studied as received from the manufacturer - with no handling or cleaning (No. 802). The final two lenses had both been polished using high-purity ceria, cerium oxide (No. 800 and No. 801). The difference between these two was that No. 800 was polished using a nylon lap, and No. 801 was polished using pitch as a lap. The 800-series lenses were all made from the same batch, and constituted the major part of the investigation

  11. Polishing and toothbrushing alters the surface roughness and gloss of composite resins.

    Science.gov (United States)

    Kamonkhantikul, Krid; Arksornnukit, Mansuang; Takahashi, Hidekazu; Kanehira, Masafumi; Finger, Werner J

    2014-01-01

    This study aimed to investigate the surface roughness and gloss of composite resins after using two polishing systems and toothbrushing. Six composite resins (Durafill VS, Filtek Z250, Filtek Z350 XT, Kalore, Venus Diamond, and Venus Pearl) were evaluated after polishing with two polishing systems (Sof-Lex, Venus Supra) and after toothbrushing up to 40,000 cycles. Surface roughness (Ra) and gloss were determined for each composite resin group (n=6) after silicon carbide paper grinding, polishing, and toothbrushing. Two-way ANOVA indicated significant differences in both Ra and gloss between measuring stages for the composite resins tested, except Venus Pearl, which showed significant differences only in gloss. After polishing, the Filtek Z350 XT, Kalore, and Venus Diamond showed significant increases in Ra, while all composite resin groups except the Filtek Z350 XT and Durafill VS with Sof-Lex showed increases in gloss. After toothbrushing, all composite resin demonstrated increases in Ra and decreases in gloss.

  12. Surface texture and roughness of polished nanofill and nanohybrid resin composites.

    Science.gov (United States)

    Endo, Tatsuo; Finger, Werner J; Kanehira, Masafumi; Utterodt, Andreas; Komatsu, Masashi

    2010-03-01

    Nanofiller-containing resin composites have gained appreciable market share in dentistry due to their claims of high mechanical strength and low polymerization contraction. In this study, the polishability of one nanofill (Filtek Supreme XT/FIL) and three nanohybrid materials (Grandio/GRA, Tetric EvoCeram/TET, Venus Diamond/VED) was investigated using surface profilometry and SEM. After the specimens were cured under a Mylar strip or pre-ground with 600-grit SiC paper, three polishing systems were applied and their polishing effects compared: diamond polishing points, a diamond paste, and urethane-backed aluminum oxide disks. Except for the profilometry results obtained by glass filler-containing GRA and VED with one polishing system that comprised the consecutive application of diamond particles and a diamond polishing paste, the final roughness (Ra) of all other specimens were lower than the clinically acceptable 0.2 microm threshold. The surface textures of the polished nanofill FIL and nanohybrid TET were uniformly smooth, whereas relief polishing effects and filler extrusion of varying extents were seen on the nanohybrid composites GRA and VED.

  13. Surface morphology changes of acrylic resins during finishing and polishing phases

    Directory of Open Access Journals (Sweden)

    Glaucio Serra

    2013-12-01

    Full Text Available INTRODUCTION: The finishing and polishing phases are essential to improve smoothness and shining on the surface of acrylic resins used to make removable orthodontic appliances. A good surface finishing reduces roughness, which facilitates hygiene, prevents staining and provides greater comfort to the patients. OBJECTIVE: The aim of this paper was to analyze the changes on surface morphology of acrylic resins during finishing and polishing phases. METHODS: Thirty discs (10 mm in diameter and 5 mm in length were made with acrylic resin and randomly divided into ten groups. The control group did not receive any treatment while the other groups received gradual finishing and polishing. The last group received the entire finishing and polishing procedures. Surface morphology was qualitatively analyzed through scanning electron microscopy and quantitatively analyzed through a laser profilometer test. RESULTS: The acrylic resin surfaces without treatment showed bubbles which were not observed in the subsequent phases. Wearing out with multilaminated burs, finishing with wood sandpaper and finishing with water sandpaper resulted in surfaces with decreasing irregularities. The surfaces that were polished with pumice and with low abrasive liquids showed high superficial smoothness. CONCLUSION: Highly smooth acrylic resin surfaces can be obtained after mechanical finishing and polishing performed with multilaminated burs, wood sandpaper, water sandpaper, pumice and low abrasive liquids.

  14. Effect of polishing systems on stain susceptibility and surface roughness of nanocomposite resin material.

    Science.gov (United States)

    Barakah, Haifa M; Taher, Nadia M

    2014-09-01

    Different polishing systems vary in their effect on reducing surface roughness and stain susceptibility of dental composite resin materials. The purpose of this study was to compare the effect of 3 polishing systems on the stain susceptibility and surface roughness of 2 nanocomposite resins and a microhybrid composite resin. Forty-five disks (2×10 mm) each were fabricated of 2 nanocomposite resins (Filtek Supreme XT and Tetric EvoCeram) and 1 microhybrid composite resin (Z250). Both sides of the disks were wet finished, and 1 side was polished with PoGo, Astropol, or Hi-Shine (n=5). Unpolished surfaces served as controls. The average roughness (Ra, μm) was measured with a profilometer, and the baseline color was recorded with a spectrophotometer. All specimens were incubated while soaking in a staining solution of coffee, green tea, and berry juice for 3 weeks. The color was recorded again, and the data were analyzed with 2-way ANOVA at α=.05 and Tukey multiple comparison tests. All polishing systems improved the staining resistance of Filtek Supreme XT and Z250 but did not affect that of Tetric EvoCeram. The surface color of Filtek Supreme XT was changed significantly and was the smoothest after polishing with PoGo, whereas Hi-Shine produced significantly rougher surfaces but with the lowest color change. Hi-Shine produced the highest color change in Z250. The surface roughness did not differ significantly between the other polishing systems. Tetric EvoCeram showed no significant differences in color change or surface roughness. Staining susceptibility and surface roughness depend mainly on material composition and on the polishing procedures. Polishing improves the staining resistance of composite resins. Nanocomposite resins did not exhibit better staining resistance or surface roughness than microhybrid composite resin. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  15. Effects of different polishing techniques on the surface roughness of dental porcelains

    Directory of Open Access Journals (Sweden)

    Işil Sarikaya

    2010-02-01

    Full Text Available OBJECTIVE: The purpose of this study was to evaluate the effects of different polishing techniques on the surface roughness of dental porcelains. MATERIAL AND METHODS: Fifty-five cylindirical specimens (15x2 mm were prepared for each feldspathic (Vita VMK 95, Ceramco III and low-fusing dental porcelain (Matchmaker. Fifty-five specimens of machinable feldspathic porcelain blocks (Vitablocs Mark II, (12x14x18 mm were cut into 2-mm-thick slices (12x14 mm with low speed saw. The prepared specimens were divided into 11 groups (n=5 representing different polishing techniques including control ((C no surface treatment, glaze (G and other 9 groups that were finished and polished with polishing discs (Sof-Lex (Sl, two porcelain polishing kits (NTI (Pk, Dialite II (Di, a diamond polishing paste (Sparkle (Sp, a zirconium silicate based cleaning and polishing prophy paste (Zircate (Zr, an aluminum oxide polishing paste (Prisma Gloss (Pg, and combinations of them. The surface roughness of all groups was measured with a profilometer. The data were analyzed with a 2-way analysis of variance, and the mean values were compared by the Tukey Honestly Significant Difference test (a=0.05. RESULTS: For all porcelain material groups, the lowest Ra values were observed in Group Gl, Group Sl, Group Pk, and Group Di, which were not significantly different from each other (p>0.05.When comparing the 4 different porcelain materials, the machinable feldspathic porcelain block group (Mark II demonstrated statistically significantly less Ra values than the other porcelain materials tested (p<0.05. No significant difference was observed between the VMK 95 and Ceramco III porcelain groups (p=0.919, also these groups demonstrated the highest Ra values. CONCLUSION: Subjected to surface roughness, the surfaces obtained with polishing and/or cleaning-prophy paste materials used alone were rougher compared to the surfaces finished using Sof-lex, Dialite, and NTI polishing kit

  16. A quantitative method to estimate high gloss polished tool steel surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Rebeggiani, S; Rosen, B-G [Halmstad University, The Functional Surfaces Research Group, Box 823, SE-301 18 HALMSTAD (Sweden); Sandberg, A, E-mail: sabina.rebeggiani@hh.se [Uddeholms AB, SE-683 85 Hagfors (Sweden)

    2011-08-19

    Visual estimations are today the most common way to assess the surface quality of moulds and dies; a method that are both subjective and, with today's high demands on surfaces, hardly usable to distinguish between the finest surface qualities. Instead a method based on non-contact 3D-surface texture analysis is suggested. Several types of tool steel samples, manually as well as machine polished, were analysed to study different types of surface defects such as pitting, orange peel and outwardly features. The classification of the defect structures serves as a catalogue where known defects are described. Suggestions of different levels of 'high surface quality' defined in numerical values adapted to high gloss polished tool steel surfaces are presented. The final goal is to develop a new manual that can work as a 'standard' for estimations of tool steel surfaces for steel producers, mould makers, polishers etc.

  17. [Comparison of surface roughness of nanofilled and microhybrid composite resins after curing and polishing].

    Science.gov (United States)

    Jiang, Hong; Lv, Da; Liu, Kailei; Zhang, Weisheng; Yao, Yao; Liao, Chuhong

    2014-05-01

    To compare the surface roughness of nanofilled dental composite resin and microhybrid composite resins after curing and polishing. A nanofilled composite (Z350) and 4 microhybrid composites (P60, Z250, Spectrum, and AP-X) were fabricated from the lateral to the medial layers to prepare 8 mm×8 mm×5 mm cubical specimens. The 4 lateral surfaces of each specimens were polished with abrasive disks (Super-Snap). Profilometer was used to test the mean surface roughness (Ra) after polishing. P60 had the lowest Ra (0.125∓0.030 µm) followed by Z250 and Spectrum. The Ra of Z350 (0.205∓0.052 µm) was greater than that of the other 3 resins, and AP-X had the roughest surfaces. Under scanning electron microscope, the polished faces of P60 resin were characterized by minor, evenly distributed particles with fewer scratches; the polished faces of Z350 presented with scratches where defects of the filling material could be seen. The nanofilled composite Z350 has smooth surface after polishing by abrasive disks, but its smoothness remains inferior to that of other micro-hybrid composite resins.

  18. Surface Characterization of LMMS Molybdenum Disilicide Coated HTP-8 Using Arc- Jet Hypersonic Flow

    Science.gov (United States)

    Stewart, David A.

    2000-01-01

    Surface properties for an advanced Lockheed Martin Missile and Space (LMMS) molybdenum disilicide coated insulation (HTP-8) were determined using arc-jet flow to simulate Earth entry at hypersonic speeds. The catalytic efficiency (atom recombination coefficients) for this advanced thermal protection system was determined from arc-jet data taken in both oxygen and nitrogen streams at temperatures ranging from 1255 K to roughly 1600 K. In addition, optical and chemical stability data were obtained from these test samples.

  19. Research on Laser Micro Polishing of SLS Technology Sintered Iron-Based Powder Surface

    Directory of Open Access Journals (Sweden)

    Gerda Vaitkūnaitė

    2015-03-01

    Full Text Available The article analyzes laser micro polishing of 1.2083 steel samples produced applying selective laser sintering (SLS method. The study has evaluated the distribution of the shape, size and temperature of the laser beam treated area in the surface layer of sintered and laser polished samples. Experimental tests have shown the impact of the technical parameters of laser micro polishing on the width and hardness of the impact zone of the treated sample. The microstructure analysis of laser treated and untreated areas of the material has been made.

  20. Surface roughness of novel resin composites polished with one-step systems.

    Science.gov (United States)

    Ergücü, Z; Türkün, L S

    2007-01-01

    This study: 1) analyzed the surface roughness of five novel resin composites that contain nanoparticles after polishing with three different one-step systems and 2) evaluated the effectiveness of these polishers and their possible surface damage using scanning electron microscope (SEM) analysis. The resin composites evaluated in this study include CeramX, Filtek Supreme XT, Grandio, Premise and Tetric EvoCeram. A total of 100 discs (20/resin composites, 10 x 2 mm) were fabricated. Five specimens/resin composites cured under Mylar strips served as the control. The samples were polished for 30 seconds with PoGo, OptraPol and One Gloss discs at 15,000 rpm using a slow speed handpiece. The surfaces were tested for roughness (Ra) with a surface roughness tester and examined with SEM. One-way ANOVA was used for statistical analysis (p = 0.05). For all the composites tested, differences between the polishing systems were found to be significant (p Grandio, Mylar and PoGo created equally smooth surfaces, while OptraPol and One Gloss produced equally rougher surfaces. Tetric EvoCeram exhibited the roughest surface with OptraPol, while no significant differences were found between Premise and CeramX. According to SEM images, OptraPol and One Gloss scratched and plucked the particles away from the surface, while PoGo created a uniform finish, although the roughness values were not the same for each composite. Effectiveness of the polishers seems to be material dependent.

  1. Effect of physicochemical factors on the microplasticity of the surface layer of molybdenum single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Savenko, V.I.; Kuchumova, V.M.; Kochanova, L.A.; Shchukin, E.D.

    1984-07-01

    The microplastic properties of the surface layer of molybdenum single crystals produced by electron-beam zone melting have been investigated experimentaly using ultramicrosclerometry and microindentation techniques. It is found that the 111 plane has the highest susceptibility to plastic damage, while the 100 plane is the hardest. An analysis of the stressed state of the material under an indenter shows that the dislocation density along the loading paths, which characterizes the microplasticity of the material, is largely determined by the crystallography of the lattice, i.e., by the arrangement and the number of effective slip systems in specimens of different orientations. The effect of a monolayer octadecylamine film on the microplastic behavior of molybdenum single crystals is discussed.

  2. Nitrogen diffusion in near-surface range of ion doped molybdenum

    CERN Document Server

    Zamalin, E Y

    2001-01-01

    The dynamics of change in nitrogen near-the-surface concentration in the Mo ion-alloyed monocrystalline foil is studied through the Auger-electron spectroscopy and the secondary ion mass spectrometry. The implantation dose constituted 5 x 10 sup 1 sup 7 ion/cm sup 2 and the implantation energy equaled 50 and 100 keV. The samples diffusion annealing was performed at the temperature of 800-900 deg C. The evaluation of the nitrogen diffusion coefficient indicates the values by 3-5 orders lesser than the diffusion coefficient in the nitrogen solid-state solution in the molybdenum. At the same time the molybdenum self-diffusion coefficient value is by 3-5 orders lesser as compared to the obtained value. The supposition is made, the the surplus nitrogen relative to the solubility limit is deposited on the radiation defects and in the process of the diffusion annealing it nitrates together with them

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

    DEFF Research Database (Denmark)

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

    2016-01-01

    The applicability of acoustic emission (AE) measurements for in-process monitoring of surface generation in the robot-assisted polishing (RAP) was investigated. Surface roughness measurements require interruption of the process, proper surface cleaning and measurements that sometimes necessitate......-process determination of the process endpoint. This makes it possible to reliably determine the right time for changing the polishing media to finer abrasive when applying a given set of parameters is no longer effective to create a smoother surface, thus improving the efficiency of the process. The findings enabling...

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

    DEFF Research Database (Denmark)

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

    2012-01-01

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

  5. On the generation of surface depressions in polishing polycrystalline diamond compacts

    International Nuclear Information System (INIS)

    Tang, Fengzai; Chen, Yiqing; Zhang, Liangchi

    2014-01-01

    This paper investigates the surface depressions generated during the polishing of the (1 1 1) surfaces of polycrystalline diamond (PCD) compacts when using the dynamic friction polishing (DFP) method. It was found that surface depressions of six-sided faces along octahedral planes were the typical features created by the DFP. Although the size of the well-developed depressions can vary significantly, the rectilinear edges are always aligned with the directions. Pronounced {1 1 1} planar defects (i.e., twins) were revealed underneath a depression apex. The interception of the defect plane with the polished surface accounts for the generation of the aligned depressions and for the discernible asymmetry of the pyramidal faces with respect to the (1 1 1) plane. It was revealed that the attached debris layer on the PCD surfaces contained sp 2 -bounded amorphous carbon and nano-sized crystals. (paper)

  6. [Surface roughness and gloss of novel flowable composites after polishing and simulated brushing wear].

    Science.gov (United States)

    Wang, R L; Yuan, C Y; Pan, Y X; Tian, F C; Wang, Z H; Wang, X Y

    2017-04-09

    Objective: To investigate surface properties of novel flowable composites after polishing and simulated brushing wear, compared to their pasty counterpart. Methods: Composites employed in this study were: three flowable composites (A1: Clearfil Majesty ES Flow; B1: Beautifil Flow Plus F00; C1: Filtek Bulk Fill) and three paste composites (A2: Clearfil Majesty; B2: Beautifil; C2: Filtek Z350. Eleven disk-shaped specimens were made for each material. The specimens were cured, then subjected to sandpaper finishing for 20 s, one-step polishing for 30 s, finally subjected to simulated brushing for 10 000 cycles. Surface roughness and glossiness were measured before finishing, after finishing, after polishing, after 5 000 brushing cycles and after 10 000 brushing cycles, respectively. Data obtained were analyzed using two-way ANOVA method. Scanning electron microscope was employed to examine the microscopic appearance of each material. Results: Surface roughness (0.11~0.22 μm) and glossiness (74.25~86.48 GU) of each material were similar after one-step polishing. After brushing simulation, roughness increased significantly and glossiness decreased significantly for each material ( Pcomposites of group A1 and B1 tested in the present setup showed better surface properties compared to their pasty counterpart (group A2 and B2). Conclusions: Within the limit of this study, flowable composites tested in the present research can obtain similar surface polish or even better than the paste composite counterpart.

  7. Effect of one-step polishing systems on surface roughness of different flowable restorative materials.

    Science.gov (United States)

    Ozel, Emre; Korkmaz, Yonca; Attar, Nuray; Karabulut, Erdem

    2008-11-01

    The purpose of this study was to investigate the influence of one-step polishing systems on the surface roughness of different flowable composites and a microhybrid composite. A total of 120 disks were fabricated and divided into six groups according to the different composite restorative materials tested (n = 20). Each group was further divided into four subgroups according to the polishing system (n = 5). For the control group, samples were left undisturbed after removal of Mylar strip. For the other three subgroups, samples were polished with PoGo, OptraPol, or Sof-Lex disks. Surface roughness was determined using a profilometer and observed under scanning electron microscope (SEM). Data were analyzed by one-way ANOVA and Duncan's multiple range test. For Tetric Flow, Grandio Flow, Filtek Supreme XT Flow, and Admira Flow, their lowest surface roughness values were obtained in Mylar Strip and PoGo groups. For Compoglass Flow, there were no significant differences between Mylar Strip, PoGo, and OptraPol. For Filtek Z250, the lowest surface roughness value was obtained with Mylar Strip. In light of the surface roughness results obtained, one-step polishing systems seemed to be a good choice for polishing flowable composites.

  8. Three-dimensional evaluation of surface roughness of resin composites after finishing and polishing.

    Science.gov (United States)

    Nair, Veena S; Sainudeen, Shan; Padmanabhan, Prabeesh; Vijayashankar, L V; Sujathan, Unu; Pillai, Rajesh

    2016-01-01

    This study aims to investigate the effects of finishing and polishing procedures on four novel resin composites using three-dimensional optical profilometer. Four composites classified according to their filler size, were selected: Filtek™ Z350 XT/Nanofill (3M™ ESPE™), Esthet-X HD/Hybrid (Dentsply Caulk), Te Econom/Microfill (Ivoclar Vivadent(®)), Tetric EvoCeram(®) /Nanohybrid (Ivoclar Vivadent(®)). Composite specimens were made in Plexiglass mold and polished with Soflex (3M ESPE), Enhance + Pogo (Dentsply Caulk). Both the systems were used according to the manufacturers' instructions, and the polished surfaces were assessed with an optical profilometer. Kruskal-Wallis test and further pairwise comparison were performed by Mann-Whitney test. The smoothest surfaces for all the resin composites tested were obtained from the Mylar strip; statistically significant differences were observed among them (P = 0.001). The order of composites was ranked from the lowest to highest surface roughness; Filtek Z350 XT Econom < Tetric EvoCeram < Esthet XHD. Pairwise multiple comparison with Mann-Whitney test showed Filtek Z350 to have the smoothest surface and the least with Teric EvoCeram. Among the polishing systems, Soflex showed the smoothest surface and was significantly different from Pogo (P = 0.046). The effectiveness of the polishing systems seems to be dependent on the material used, treatment modality and also on the filler particle size.

  9. Thermal management of metallic surfaces: evaporation of sessile water droplets on polished and patterned stainless steel

    Science.gov (United States)

    Czerwiec, T.; Tsareva, S.; Andrieux, A.; Bortolini, G. A.; Bolzan, P. H.; Castanet, G.; Gradeck, M.; Marcos, G.

    2017-10-01

    This communication focus on the evaporation of sessile water droplets on different states of austenitic stainless steel surfaces: mirror polished, mirror polished and aged and patterned by sputtering. The evolution of the contact angle and of the droplet diameter is presented as a function of time at room temperature. For all the surface states, a constant diameter regime (CCR) is observed. An important aging effect on the contact angle is measured on polished surfaces due to atmospheric contamination. The experimental observations are compared to a quasi-static evaporation model assuming spherical caps. The evolution of the droplet volume as a function of time is almost linear with the evaporation time for all the observed surfaces. This is in accordance with the model prediction for the CCR mode for small initial contact angles. In our experiments, the evaporation time is found to be linearly dependent on the initial contact angle. This dependence is not correctly described by the evaporation model

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-09-22

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

  11. The effect of finishing and polishing on surface roughness of a processed resilient denture liner.

    Science.gov (United States)

    Loney, R W; Moulding, M B

    1993-01-01

    A raised ridge on a Molloplast-B sample was removed using one of three burs, four stones, or a coarse sandpaper disc. Samples were polished using pumice alone, tin oxide alone, or both agents. A flat, unfinished sample served as a control. The average surface roughness was measured after reductions and subsequent polishings. The length of time required for initial reduction was recorded. Average surface roughness measurements ranged from 16.0 to 1.4 microns, with the control measuring 0.66 micron. Without polishing, burs produced rougher surfaces than stones and required longer times for reduction. Bur samples also remained rougher than stone samples after pumicing. No significant differences were found between treatments or controls after the use of either a combination of pumice and tin oxide or tin oxide alone.

  12. Efficacy of polishing kits on the surface roughness and color stability of different composite resins.

    Science.gov (United States)

    Kocaagaoglu, H; Aslan, T; Gürbulak, A; Albayrak, H; Taşdemir, Z; Gumus, H

    2017-05-01

    Different polishing kits may have different effects on the composite resin surfaces. The aim of this study was to evaluate the surface roughness and color stability of four different composites which was applied different polishing technique. Thirty specimens were made for each composite resin group (nanohybrid, GrandioSo-GS; nanohybrid, Clearfil Majesty Esthetic-CME; hybrid, Valux Plus-VP; micro-hybrid, Ruby Comp-RC; [15 mm in diameter and 2 mm height]), with the different monomer composition and particle size from a total of 120 specimens. Each composite group was divided into three subgroups (n = 10). The first subgroup of the each composite subgroups served as control (C) and had no surface treatment. The second subgroup of the each composite resin groups was polished with finishing discs (Bisco Finishing Discs; Bisco Inc., Schaumburg, IL, USA). The third subgroup of the each composite resin was polished with polishing wheel (Enhance and PoGo, Dentsply, Konstanz, Germany). The surface roughness and the color differences measurement of the specimens were made and recorded. The data were compared using Kruskal-Wallis test, and regression analysis was used in order to examine the correlation between surface roughness and color differences of the specimens (α = 0.05). The Kruskal-Wallis test indicated significant difference among the composite resins in terms of ΔE (P composite resins in terms of surface roughness (P > 0.05). Result of the regression analysis indicated statistically significant correlation between Ra and ΔE values (P < 0.05, r2 = 0.74). The findings of the present study have clinical relevance in the choice of polishing kits used.

  13. Temperature dependent surface modification of molybdenum due to low energy He+ ion irradiation

    International Nuclear Information System (INIS)

    Tripathi, J.K.; Novakowski, T.J.; Joseph, G.; Linke, J.; Hassanein, A.

    2015-01-01

    In this paper, we report on the temperature dependent surface modifications in molybdenum (Mo) samples due to 100 eV He + ion irradiation in extreme conditions as a potential candidate to plasma-facing components in fusion devices alternative to tungsten. The Mo samples were irradiated at normal incidence, using an ion fluence of 2.6 × 10 24 ions m −2 (with a flux of 7.2 × 10 20 ions m −2 s −1 ). Surface modifications have been studied using high-resolution field emission scanning electron-(SEM) and atomic force (AFM) microscopy. At 773 K target temperature homogeneous evolution of molybdenum nanograins on the entire Mo surface were observed. However, at 823 K target temperature appearance of nano-pores and pin-holes nearby the grain boundaries, and Mo fuzz in patches were observed. The fuzz density increases significantly with target temperatures and continued until 973 K. However, at target temperatures beyond 973 K, counterintuitively, a sequential reduction in the fuzz density has been seen till 1073 K temperatures. At 1173 K and above temperatures, only molybdenum nano structures were observed. Our temperature dependent studies confirm a clear temperature widow, 823–1073 K, for Mo fuzz formation. Ex-situ high resolution X-ray photoelectron spectroscopy studies on Mo fuzzy samples show the evidence of MoO 3 3d doublets. This elucidates that almost all the Mo fuzz were oxidized during open air exposure and are thick enough as well. Likewise the microscopy studies, the optical reflectivity measurements also show a sequential reduction in the reflectivity values (i.e., enhancement in the fuzz density) up to 973 K and after then a sequential enhancement in the reflectivity values (i.e., reduction in the fuzz density) with target temperatures. This is in well agreement with microscopy studies where we observed clear temperature window for Mo fuzz growth

  14. Tribochemical interaction between nanoparticles and surfaces of selective layer during chemical mechanical polishing

    Energy Technology Data Exchange (ETDEWEB)

    Ilie, Filip, E-mail: filip@meca.omtr.pub.ro [Polytechnic University of Bucharest, Department of Machine Elements and Tribology (Romania)

    2013-11-15

    Nanoparticles have been widely used in polish slurries such as those in the chemical mechanical polishing (CMP) process. For understanding the mechanisms of CMP, an atomic force microscope (AFM) is used to characterize polished surfaces of selective layers, after a set of polishing experiments. To optimize the CMP polishing process, one needs to get information on the interaction between the nano-abrasive slurry nanoparticles and the surface of selective layer being polished. The slurry used in CMP process of the solid surfaces is slurry with large nanoparticle size colloidal silica sol nano-abrasives. Silica sol nano-abrasives with large nanoparticle are prepared and characterized by transmission electron microscopy, particles colloidal size, and Zeta potential in this paper. The movement of nanoparticles in liquid and the interaction between nanoparticles and solid surfaces coating with selective layer are very important to obtain an atomic alloy smooth surface in the CMP process. We investigate the nanoparticle adhesion and removal processes during CMP and post-CMP cleaning. The mechanical interaction between nanoparticles and the wafer surface was studied using a microcontact wear model. This model considers the nanoparticle effects between the polishing interfaces during load balancing. Experimental results on polishing and cleaning are compared with numerical analysis. This paper suggests that during post-CMP cleaning, a combined effort in chemical and mechanical interaction (tribochemical interactions) would be effective in removal of small nanoparticles during cleaning. For large nanoparticles, more mechanical forces would be more effective. CMP results show that the removal rate has been improved to 367 nm/min and root mean square (RMS) of roughness has been reduced from 4.4 to 0.80 nm. Also, the results show that the silica sol nano-abrasives about 100 nm are of higher stability (Zeta potential is −65 mV) and narrow distribution of nanoparticle

  15. Effects of surface polishing and annealing on the optical conductivity of intermetallic compounds

    CERN Document Server

    Rhee, J Y

    1999-01-01

    The optical conductivity spectra of several intermetallic compounds were measured by spectroscopic ellipsometry. Three spectra were measured for each compound; just after the sample was mechanically polished, at high temperature, and after the sample was annealed at 110 .deg. C for at least one day and cooled to room temperature. An equiatomic FeTi alloy showed the typical effects of annealing after mechanical polishing of surface. The spectrum after annealing had a larger magnitude and sharper structures than the spectrum before annealing. We also observed shifts of peaks in the spectrum. A relatively low-temperature annealing gave rise to unexpectedly substantial effects, and the effects were explained by recrystallization and/or a disorder -> order transition of the surface of the sample which was damaged and, hence, became highly disordered by mechanical polishing. Similar effects were also observed when the sample temperature was lowered. The observed changes upon annealing could partly be explained by p...

  16. Material removal and surface figure during pad polishing of fused silica

    Energy Technology Data Exchange (ETDEWEB)

    Suratwala, T I; Feit, M D; Steele, W A

    2009-05-04

    The material removal and surface figure after ceria pad polishing of fused silica glass have been measured and analyzed as a function of kinematics, loading conditions, and polishing time. Also, the friction at the workpiece/lap interface, the slope of the workpiece relative to the lap plane, and lap viscoelastic properties have been measured and correlated to material removal. The results show that the relative velocity between the workpiece & lap (determined by the kinematics) and the pressure distribution determine the spatial and temporal material removal and hence the final surface figure of the workpiece. In the case where the applied loading and relative velocity distribution over the workpiece are spatially uniform, a significant non-uniform spatial material removal from the workpiece surface is observed. This is due to a non-uniform pressure distribution resulting from: (1) a moment caused by a pivot point and interface friction forces; (2) viscoelastic relaxation of the polyurethane lap; and (3) a physical workpiece/lap interface mismatch. Both the kinematics and these contributions to the pressure distribution are quantitatively described, and then combined to form a spatial and temporal Preston model & code for material removal (called Surface Figure or SurF{copyright}). The surface figure simulations are consistent with the experiment for a wide variety of polishing conditions. This study is an important step towards deterministic full-aperture polishing, which would allow optical glass fabrication to be performed in a more repeatable, less iterative, and hence more economical manner.

  17. Comparison of different polishing methods on the surface roughness of microhybrid, microfill, and nanofill composite resins.

    Science.gov (United States)

    Moda, Mariana D; Godas, André Gustavo de L; Fernandes, Juliana C; Suzuki, Thaís Y U; Guedes, Ana Paula A; Briso, André L F; Bedran-Russo, Ana Karina; Dos Santos, Paulo H

    2018-02-01

    The aim of the present study was to evaluate the effect of different polishing methods on the surface roughness of resin-based composites subjected to a thermocycling procedure. A total of 192 specimens were divided into 24 groups, according to composite materials (Filtek Z250, Point 4, Renamel Nanofill, Filtek Supreme Plus, Renamel Microfill, and Premise) and finishing and polishing systems (Sof-Lex Pop On, Super Snap, Flexidisc, and Flexidisc+Enamelize). The specimens were subjected to thermocycling (5000 cycles). Filtek Supreme Plus showed the lowest surface roughness values before thermocycling. After thermocycling, Filtek Supreme Plus continued to have the lowest surface roughness, with a statistically-significant difference for the other materials. After thermocycling, there was no statistically-significant difference among all the polishing techniques studied. The thermocycling was concluded as being able to change composite resins' surface roughness, whereas different finishing and polishing methods did not result in surface roughness changes after thermocycling. © 2017 John Wiley & Sons Australia, Ltd.

  18. The effect of scattered light sensor orientation on roughness measurement of curved polished surfaces

    DEFF Research Database (Denmark)

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

    2014-01-01

    Light scattering is a method for surface roughness measurements well suitable for use in a production environment thanks to its fast measurement rate, insensitivity to vibrations and to small misalignments. The method is however affected by several other factors. In this paper, the effect of angu...... of angular orientation of a commercial scattered light sensor on roughness measurements of polished cylindrical surfaces with crossed surface lay is investigated to document the robustness of the method....

  19. Nitrides and carbides of molybdenum and tungsten with high specific-surface area: their synthesis, structure, and catalytic properties

    International Nuclear Information System (INIS)

    Volpe, L.

    1985-01-01

    Temperature-programmed reactions between trioxides of molybdenum or tungsten and ammonia provide a new method to synthesize dimolybdenum and ditungsten nitrides with specific surface areas to two-hundred-and-twenty and ninety-one square meters per gram, respectively. These are the highest values on record for any unsupported metallic powders. They correspond to three-four nonometer particles. The reaction of molybdenum trioxide with ammonia is topotactic in the sense that one-zero-zero planes of dimolybdenum nitride are parallel to zero-one-zero planes of molybdenum trioxide. As the trioxide transforms, it passes through an oxynitride intermediate with changing bulk structure and increasing surface area and extent of reduction. The nitride product consists of platelets, pseudomorphous with the original trioxide, which can be regarded as highly porous defect single crystals. By treating small particles of dimolybdenum or ditungsten nitride with methane-dihydrogen mixtures it is possible to replace interstitial nitrogen atoms by carbon atoms, without sintering, and thus to prepare carbides of molybdenum and tungsten with very high specific surface areas. Molybdenum nitride powders catalyze ammonia synthesis. A pronounced increase in the catalytic activity with increasing particle size confirms the structure-sensitive character of this reaction

  20. Mechanical polishing as an improved surface treatment for platinum screen-printed electrodes

    Directory of Open Access Journals (Sweden)

    Junqiao Lee

    2016-07-01

    Full Text Available The viability of mechanical polishing as a surface pre-treatment method for commercially available platinum screen-printed electrodes (SPEs was investigated and compared to a range of other pre-treatment methods (UV-Ozone treatment, soaking in N,N-dimethylformamide, soaking and anodizing in aqueous NaOH solution, and ultrasonication in tetrahydrofuran. Conventional electrochemical activation of platinum SPEs in 0.5 M H2SO4 solution was ineffective for the removal of contaminants found to be passivating the screen-printed surfaces. However, mechanical polishing showed a significant improvement in hydrogen adsorption and in electrochemically active surface areas (probed by two different redox couples due to the effective removal of surface contaminants. Results are also presented that suggest that SPEs are highly susceptible to degradation by strong acidic or caustic solutions, and could potentially lead to instability in long-term applications due to continual etching of the binding materials. The ability of SPEs to be polished effectively extends the reusability of these traditionally “single-use” devices. Keywords: Screen-printed electrodes, Polishing, Platinum, Activation, Pre-treatment, Cyclic voltammetry

  1. Surface roughness and hardness of a composite resin: influence of finishing and polishing and immersion methods

    Directory of Open Access Journals (Sweden)

    Ana Luísa Botta Martins de Oliveira

    2010-09-01

    Full Text Available This study evaluated the finishing and polishing effect on the surface roughness and hardness of the Filtek Supreme XT, in fluoride solutions. Specimens were prepared (n = 140 with half of the samples finished and polished with Super-Snap® disks. The experimental groups were divided according to the presence or absence of finishing and polishing and immersion solutions (artificial saliva, sodium fluoride solution at 0.05% - manipulated, Fluordent Reach, Oral B, Fluorgard. The specimens remained immersed in artificial saliva for 24 hours and were then subjected to initial analysis (baseline of surface roughness and Vickers microhardness. Next, they were immersed in different fluoride solutions for 1 min/day, for 60 days. Afterwards, a new surface roughness and microhardness reading was conducted. The data were submitted to a two-way ANOVA and Tukey's test (5% significance level. For the comparison of mean roughness and hardness at baseline and after 60 days, the paired Student t test was used. The results showed that the surface roughness and microhardness of the Filtek Supreme XT were influenced by the finishing and polishing procedure, independently of the immersion methods.

  2. Effect of different polishing methods on surface roughness of provisional prosthetic materials

    Directory of Open Access Journals (Sweden)

    Ivian Verena Maia Tupinamba

    2018-01-01

    Conclusions: Within the limitations of this study, it was concluded that the most effective polishing system was the goat hair brush with diamond paste for both bis-acrylic and acrylic resins. The bis-acrylic resins exhibited significantly smoother surfaces than the acrylic resins.

  3. Comparative evaluation of effect of different polishing systems on surface roughness of composite resin: An in vitro study.

    Science.gov (United States)

    Chour, Rashmi G; Moda, Aman; Arora, Arpana; Arafath, Muhmmed Y; Shetty, Vikram K; Rishal, Yousef

    2016-08-01

    Satisfactory composite restoration depends upon its smooth finish, quality of polishing agents, type of composite material used, and its composition. The present study evaluated the effect of different polishing systems on the surface roughness of composite resin. Forty discs of composite were prepared and equally subjected to different finishing and polishing procedures; (i) unpolished control group, (ii) sof-lex discs, (iii) diamond tips, and (iv) Astrobrush groups. Later, the surface roughness for the entire specimen was evaluated using Profilomotor. Data were tabulated and statistically analyzed using analysis of variance and Tukey's test at significance level of 0.001. Composite surface roughness after polishing was statistically significant between the groups. Sof-lex group produced lesser surface roughness compared to control, Astrobrush, and diamond group. The present study indicated that diamond tips can be used to remove rough surface whereas sof-lex can be used for final finish and polish of the composite restoration.

  4. Effect of Surface Polishing on Mercury Release from Dental Amalgam After Treatment 16% Carbamide Peroxide Gel

    Directory of Open Access Journals (Sweden)

    Z. Khamverdi

    2011-03-01

    Full Text Available Objectives: This study evaluated the effect of surface polishing on mercury release from dental amalgam after treatment with 16% carbamide peroxide gel.Materials and Methods: Ninety-six samples from two different amalgam brands were prepared in truncated cone-shaped PVC polymer molds with an external surface area of 195 mm². Half of the specimens were polished with green and red rubber, a brush and tin oxide paste at low speed. Samples were treated with 16% carbamide peroxide gel intubes containing 3 mL of carbamide peroxide gel and 0.1 mL of distilled water for 14 and 28 hours. Subsequently, carbamide peroxide gel on the sample surfaces was rinsed away with 7.0 mL of distilled water until the volume of each tube increased to 10 mL. Themercury level of each solution was measured using the VAV–440 mercury analyzer system.Considering the surface area of each amalgam disc, mercury amounts were calculated in μg ⁄mm². Data were analyzed using two-way ANOVA.Results: There were significant differences between the mean levels of mercury release from polished vs. unpolished amalgam surfaces after treatment with 16% carbamide peroxide.Increasing the storage time from 14 to 28 hours did not result in significant changes in the amount of mercury release. There was no significant interaction effect between amalgam surface polish and storage time statistically.Conclusion: Polished amalgam restorations release less mercury after treatment with carbamide peroxide bleaching gel in comparison with unpolished amalgam restorations.

  5. Formation of a deposit on workpiece surface in polishing nonmetallic materials

    Science.gov (United States)

    Filatov, Yu. D.; Monteil, G.; Sidorko, V. I.; Filatov, O. Y.

    2013-05-01

    During the last decades in the theory of machining nonmetallic materials some serious advances have been achieved in the field of applying fundamental scientific approaches to the grinding and polishing technologies for high-quality precision surfaces of electronic components, optical systems, and decorative articles made of natural and synthetic stone [1-9]. These achievements include a cluster model of material removal in polishing dielectric workpieces [1-3, 6-7] and a physical-statistical model of formation of debris (wear) particles and removal thereof from a workpiece surface [8-10]. The aforesaid models made it possible to calculate, without recourse to Preston's linear law, the removal rate in polishing nonmetallic materials and the wear intensity for bound-abrasive tools. Equally important for the investigation of the workpiece surface generation mechanism and formation of debris particles are the kinetic functions of surface roughness and reflectance of glass and quartz workpiece surfaces, which have been established directly in the course of polishing. During the in situ inspection of a workpiece surface by laser ellipsometry [11] and reflectometry [12] it was found out that the periodic change of the light reflection coefficient of a workpiece surface being polished is attributed to the formation of fragments of a deposit consisting of work material particles (debris particles) and tool wear particles [13, 14]. The subsequent studies of the mechanism of interaction between the debris particles and wear particles in the tool-workpiece contact zone, which were carried out based on classical concepts [15, 16], yielded some unexpected results. It was demonstrated that electrically charged debris and wear particles, which are located in the coolant-filled gap between a tool and a workpiece, move by closed circular trajectories enclosed in spheres measuring less than one fifth of the gap thickness. This implies that the probability of the debris and wear

  6. Effects of Wet and Dry Finishing and Polishing on Surface Roughness and Microhardness of Composite Resins

    Science.gov (United States)

    Nasoohi, Negin; Hoorizad, Maryam

    2017-01-01

    Objectives: This study aimed to assess the effect of wet and dry finishing and polishing on microhardness and roughness of microhybrid and nanohybrid composites. Materials and Methods: Thirty samples were fabricated of each of the Polofil Supra and Aelite Aesthetic All-Purpose Body microhybrid and Grandio and Aelite Aesthetic Enamel nanohybrid composite resins. Each group (n=30) was divided into three subgroups of D, W and C (n=10). Finishing and polishing were performed dry in group D and under water coolant in group W. Group C served as the control group and did not receive finishing and polishing. Surface roughness of samples was measured by a profilometer and their hardness was measured by a Vickers hardness tester. Data were analyzed using two-way ANOVA (Pcomposites (Pcomposites (Pcomposites (Pcomposite resins. PMID:29104597

  7. An in vitro investigation to compare the surface roughness of auto glazed, reglazed and chair side polished surfaces of Ivoclar and Vita feldspathic porcelain.

    Science.gov (United States)

    Sethi, Sumit; Kakade, Dilip; Jambhekar, Shantanu; Jain, Vinay

    2013-12-01

    The change in surface roughness after different surface finishing techniques has attracted the attention of several prosthodontists regarding wear of opposing teeth or restorative material and the strength; plaque retention and appearance of the restoration. However, there is considerable controversy concerning the best methods to achieve the smoothest and strongest porcelain restorations after chair side clinical adjustments. The purpose of this in vitro study was to compare the average surface roughness of a self-glazed surface, a chair side polished surface and a reglazed surface of ceramic. Two feldspathic porcelain, namely VITA VMK94 (Vita Zahnfabrik, Bad Sachingen, Germany) and IVOCLAR CLASSIC (Vivadent AG, FL-9494 Schaan, Liechtenstein) were selected to fabricate 20 specimens of each in the shape of shade guide tabs. A medium-grit diamond rotary cutting instrument was used to remove the glaze layer, and then the surface of half the specimens were re-glazed and the other half were polished using a well-defined sequence of polishing comprising of: Shofu porcelain polishing system, White gloss disc/polishing wheel, Silicone cone with diamond polishing paste and finally with small buff wheel with pumice slurry. The surface roughness (Ra) (μm) of the specimens was evaluated using a profilometer and scanning electron microscope. The data were statistically analyzed by using Student's t test. The results had shown that there is no statistically significant difference both quantitatively and qualitatively, between the surface roughness of reglazed and chair-side polished surface. In addition, both reglazed and chair-side polished surfaces are better than the autoglazed surface. Within all the groups, there is no significant difference between companies. Polishing an adjusted porcelain surface with the suggested sequence of polishing will lead to a finish similar to a re-glazed surface. Therefore chair-side polishing can be a good alternative to reglazing for

  8. Surface polishing of niobium for superconducting radio frequency (SRF) cavity applications

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Liang [College of William and Mary, Williamsburg, VA (United States)

    2014-08-01

    Niobium cavities are important components in modern particle accelerators based on superconducting radio frequency (SRF) technology. The interior of SRF cavities are cleaned and polished in order to produce high accelerating field and low power dissipation on the cavity wall. Current polishing methods, buffered chemical polishing (BCP) and electro-polishing (EP), have their advantages and limitations. We seek to improve current methods and explore laser polishing (LP) as a greener alternative of chemical methods. The topography and removal rate of BCP at different conditions (duration, temperature, sample orientation, flow rate) was studied with optical microscopy, scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD). Differential etching on different crystal orientations is the main contributor to fine grain niobium BCP topography, with gas evolution playing a secondary role. The surface of single crystal and bi-crystal niobium is smooth even after heavy BCP. The topography of fine grain niobium depends on total removal. The removal rate increases with temperature and surface acid flow rate within the rage of 0~20 °C, with chemical reaction being the possible dominate rate control mechanism. Surface flow helps to regulate temperature and avoid gas accumulation on the surface. The effect of surface flow rate on niobium EP was studied with optical microscopy, atomic force microscopy (AFM), and power spectral density (PSD) analysis. Within the range of 0~3.7 cm/s, no significant difference was found on the removal rate and the macro roughness. Possible improvement on the micro roughness with increased surface flow rate was observed. The effect of fluence and pulse accumulation on niobium topography during LP was studied with optical microscopy, SEM, AFM, and PSD analysis. Polishing on micro scale was achieved within fluence range of 0.57~0.90 J/cm2, with pulse accumulation adjusted accordingly. Larger area treatment was proved possible by

  9. Freeform surface grinding and polishing by CCOS based on industrial robot

    Science.gov (United States)

    Liu, HaiTao; Wan, YongJian; Zeng, ZhiGe; Xu, LiChao; Zhao, HongShen; Fang, Kai

    2016-10-01

    The grinding and polishing of freeform surface by using Computer Controlled Optical Surfacing (CCOS) technology are discussed. Instead of using Computer Numeric Control (CNC) machine, a 6-axises industrial robot TX200 from Stäubli Co. Ltd. is used as the motion platform. In order to perform the movement that CCOS technology needs, the coordinate system of the robot in processing is reviewed and the offline programming method for robot is presented. The material removal experiments during grinding and polishing process on the robotic CCOS platform are been carried out. A rectangular toroid surface workpiece and a circular off-axis parabolic surface workpiece are being fabricated on the robotic CCOS platform, and the latest results will be discussed here.

  10. The Effect of Finishing and Polishing Techniques on the Surface Roughness and the Color of Nanocomposite Resin Restorative Materials.

    Science.gov (United States)

    Avsar, Aysun; Yuzbasioglu, Emir; Sarac, Duygu

    2015-01-01

    Rough, poorly polished surfaces contribute to staining, plaque accumulation, gingival irritation and recurrent caries. Finishing and polishing techniques are critical factors contributing to the longevity of the direct composite resin restorations. The aim of this in vitro study was to evaluate the effects of finishing and polishing systems on surface roughness of six nanocomposite restorative resins. Thirty specimens of each restorative material (n=180) were placed in a teflon mould (6 mm in diameter and 3 mm in depth) and cured with a LED curing unit. Six specimens from each of restorative material were randomly assigned to four groups for finishing and polishing (carbide burs, diamond burs, aluminium oxide discs, silicon rubber polisher) techniques. Mylar strip formed specimens were served as control group. After finishing and polishing procedures surface roughness was evaluated by a profilometer. The data was analyzed by 2-way analysis of variance and the Tukey HSD test (α=0.05). Significant differences were found between the groups in terms roughness (prestorative materials. Although mylar matrix strip formed surfaces presents lower surface roughness values, recountouring and polishing of resin restorations are often required in clinical situations. Aluminium oxide discs and carbide finishing burs are suitable for finishing and polishing procedures for nanocomposite restorative resins.

  11. The effects of finishing and polishing techniques on surface roughness and color stability of nanocomposites.

    Science.gov (United States)

    Gönülol, Nihan; Yilmaz, Fikret

    2012-12-01

    The aim of this in vitro study was to evaluate the effects of different finishing and polishing techniques on the surface roughness and color stability of nanocomposites. Two nanohybrid (Grandio, Aelite Aesthetic Enamel), two nanofill (Filtek Supreme XT Dentin and Translucent), and a microhybrid (Filtek Z250) composites were used. Two hundred and eighty disc-shaped specimens were cured under a mylar strip. Seven specimens of each resin composite were randomly assigned to one of the seven polishing systems. A profilometer was used for assessing surface roughness. ΔE was calculated with a colorimeter at baseline and 48 h after storage in a coffee solution. The results were analysed by two-way ANOVA and Tukey's HSD test (α=0.05). Regression analysis was used to examine the correlation between surface roughness and color stability (α=0.01). There was no significant difference in R(a) values between mylar strips and Sof-Lex polishing discs (p>0.05). The highest ΔE and R(a) values were obtained from Grandio (pGrandio presented the highest surface roughness and staining susceptibility after storage in coffee solution. Aelite Aesthetic Enamel, which did not include TEGDMA in its composition, showed the least discoloration. The composites with smaller filler size did not necessarily show low surface roughness and discoloration. Staining of composite resins was dependent on monomer structure, as well as surface irregularities. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Evaluation of surface roughness of three different composite resins with three different polishing systems.

    Science.gov (United States)

    Abzal, Mohammed S; Rathakrishnan, Mensudar; Prakash, Venkatachalam; Vivekanandhan, Paramasivam; Subbiya, Arunajatesan; Sukumaran, Vridhachalam Ganapathy

    2016-01-01

    The aim of this study was to evaluate the surface roughness of three composites with three different polishing systems. Composite specimens were made from the Teflon mold with a standardized cavity size (6 mm diameter and 3 mm height). Group I - Filtek Z350XT (Nano clusters), group II - T-Econom plus (Microhybrid), group III - G-aenial Flo (True Nano). The samples were cured for 30 s from both sides with the matrices in place. The 60 samples were divided into 3 groups (N = 20), which accounted for 40 surfaces, (n = 20 × 2 = 40) in each groups. Each group were subdivided into four subgroups based on the type polishing material, subgroup A - Control, subgroup B - Astrobrush, subgroup C - Astropol, and subgroup D - Soflex spiral wheel. The samples of all groups except group A (control) were finished and polished according to the manufacture's instruction. After polishing, the roughness (Ra) of the resin composite of all the specimens were measured using a profilometer. Soflex spiral wheel (group D) significantly had the least roughness (Ra) value as compared to the other groups. Among the three resin composites tested, G-aenial Flo exhibited least Ra value due to its reduced filler size and its uniform distribution.

  13. Measurement of surface roughness changes of unpolished and polished enamel following erosion.

    Directory of Open Access Journals (Sweden)

    Francesca Mullan

    Full Text Available To determine if Sa roughness data from measuring one central location of unpolished and polished enamel were representative of the overall surfaces before and after erosion.Twenty human enamel sections (4x4 mm were embedded in bis-acryl composite and randomised to either a native or polishing enamel preparation protocol. Enamel samples were subjected to an acid challenge (15 minutes 100 mL orange juice, pH 3.2, titratable acidity 41.3mmol OH/L, 62.5 rpm agitation, repeated for three cycles. Median (IQR surface roughness [Sa] was measured at baseline and after erosion from both a centralised cluster and four peripheral clusters. Within each cluster, five smaller areas (0.04 mm2 provided the Sa roughness data.For both unpolished and polished enamel samples there were no significant differences between measuring one central cluster or four peripheral clusters, before and after erosion. For unpolished enamel the single central cluster had a median (IQR Sa roughness of 1.45 (2.58 μm and the four peripheral clusters had a median (IQR of 1.32 (4.86 μm before erosion; after erosion there were statistically significant reductions to 0.38 (0.35 μm and 0.34 (0.49 μm respectively (p<0.0001. Polished enamel had a median (IQR Sa roughness 0.04 (0.17 μm for the single central cluster and 0.05 (0.15 μm for the four peripheral clusters which statistically significantly increased after erosion to 0.27 (0.08 μm for both (p<0.0001.Measuring one central cluster of unpolished and polished enamel was representative of the overall enamel surface roughness, before and after erosion.

  14. Surface roughness and morphology of dental nanocomposites polished by four different procedures evaluated by a multifractal approach

    Energy Technology Data Exchange (ETDEWEB)

    Ţălu, Ştefan, E-mail: stefan_ta@yahoo.com [Technical University of Cluj-Napoca, Faculty of Mechanical Engineering, Department of AET, Discipline of Descriptive Geometry and Engineering Graphics, 103-105 B-dul Muncii St., Cluj-Napoca 400641, Cluj (Romania); Stach, Sebastian, E-mail: sebastian.stach@us.edu.pl [University of Silesia, Faculty of Computer Science and Materials Science, Institute of Informatics, Department of Biomedical Computer Systems, Będzińska 39, 41-205 Sosnowiec (Poland); Lainović, Tijana, E-mail: tijana.lainovic@gmail.com [University of Novi Sad, Faculty of Medicine, School of Dentistry, Hajduk Veljkova 3, 21000 Novi Sad (Serbia); Vilotić, Marko, E-mail: markovil@uns.ac.rs [University of Novi Sad, Faculty of Technical Sciences, Department for Production Engineering, Trg Dositeja Obradovića 6, 21000 Novi Sad (Serbia); Blažić, Larisa, E-mail: larisa.blazic@gmail.com [University of Novi Sad, Faculty of Medicine, School of Dentistry, Clinic of Dentistry of Vojvodina, Department of Restorative Dentistry and Endodontics, Hajduk Veljkova 3, 21000 Novi Sad (Serbia); Alb, Sandu Florin, E-mail: albflorin@yahoo.com [“Iuliu Haţieganu” University of Medicine and Pharmacy, Faculty of Dentistry, Department of Periodontology, 8 Victor Babeş St., 400012 Cluj-Napoca (Romania); Kakaš, Damir, E-mail: kakasdam@uns.ac.rs [University of Novi Sad, Faculty of Technical Sciences, Department for Production Engineering, Trg Dositeja Obradovića 6, 21000 Novi Sad (Serbia)

    2015-03-01

    Graphical abstract: - Highlights: • Multifractals are good indicators of polished dental composites 3-D surface structure. • The nanofilled composite had superior 3-D surface properties than the nanohybrid one. • Composite polishing with diamond paste created improved 3-D multifractal structure. • Recommendation: polish the composite with diamond paste if using the one-step tool. • Multifractal analysis could become essential in designing new dental surfaces. - Abstract: The objective of this study was to determine the effect of different dental polishing methods on surface texture parameters of dental nanocomposites. The 3-D surface morphology was investigated by atomic force microscopy (AFM) and multifractal analysis. Two representative dental resin-based nanocomposites were investigated: a nanofilled and a nanohybrid composite. The samples were polished by two dental polishing protocols using multi-step and one-step system. Both protocols were then followed by diamond paste polishing. The 3-D surface roughness of samples was studied by AFM on square areas of topography on the 80 × 80 μm{sup 2} scanning area. The multifractal spectrum theory based on computational algorithms was applied for AFM data and multifractal spectra were calculated. The generalized dimension D{sub q} and the singularity spectrum f(α) provided quantitative values that characterize the local scale properties of dental nanocomposites polished by four different dental polishing protocols at nanometer scale. The results showed that the larger the spectrum width Δα (Δα = α{sub max} − α{sub min}) of the multifractal spectra f(α), the more non-uniform was the surface morphology. Also, the 3-D surface topography was described by statistical parameters, according to ISO 25178-2:2012. The 3-D surface of samples had a multifractal nature. Nanofilled composite had lower values of height parameters than nanohybrid composites, due to its composition. Multi-step polishing protocol

  15. Figuring and Polishing Precision Optical Surfaces, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The requirements for cost effective manufacturing and metrology of large optical surfaces is instrumental for the success of future NASA programs such as LISA,...

  16. Effects of 2 polishing techniques and reglazing on the surface roughness of dental porcelain.

    Science.gov (United States)

    Schneider, Jacqueline; Dias Frota, Bruna Marjorie; Passos, Vanara Florencio; Santiago, Sergio Lima; Freitas Pontes, Karina Matthes de

    2013-01-01

    The aim of this study was to compare the effect of 2 polishing systems and reglazing of dental porcelain through a quantitative and qualitative analysis of surface roughness using a stylus profilometer and scanning electron microscope. Fifteen porcelain specimens (10 x 3 x 3 mm) were used. On 1 surface of each block, a layer of glaze was applied, and surface roughness (Ra) was analyzed. All specimens were ground with aluminum oxide sandpaper until the shine was removed and the resulting Ra values were obtained. Afterwards, they were randomly divided into 3 treatment groups (n = 5): Group I (GI), polished with diamond-impregnated rubber wheels; Group II (GII), polished with silicon carbide-impregnated rubber wheels; and Group III (GIII), reglazed firing procedure alone. After the treatments, new Ra measurements were done. Data were submitted to analysis of variance (ANOVA), and Tukey tests at 5%. Comparisons between ground surface and treated surface were made by paired t-test. The ground and treated Ra values (µm) were determined as follows: GI: 0.66 ± 0.14, 0.35 ± 0.06; GII: 0.60 ± 0.04, 0.09 ± 0.03; and GIII: 0.67 ± 0.05, 0.75 ± 0.24. Significant differences were found between the ground and treated values for all groups. After the treatments, all groups differed statistically (P rubber or reglazing alone were not able to achieve a satisfactory smoothness.

  17. Surface polish of PLA parts in FDM using dichloromethane vapour

    Directory of Open Access Journals (Sweden)

    Jin Yifan

    2017-01-01

    Full Text Available Fused deposition modelling has become one of the most diffused rapid prototyping techniques, which is widely used to fabricate prototypes. However, further application of this technology is severely limited by poor surface roughness. Thus it is necessary to adopt some operations to improve surface quality. Chemical finishing is typically employed to finish parts in fused deposition modelling (FDM. The purpose of this paper is to decrease the surface roughness for polylactic acid (PLA parts in FDM. The chemical reaction mechanism during the treating process is analysed. Then NaOH solution and dichloromethane vapour are used to treat FDM specimens respectively. A 3D laser microscope has been applied to assess the effects in terms of surface topography and roughness. The experimental results show that treatment using dichloromethane vapour performs much better than NaOH solution. Compared with the untreated group, surface roughness obtained through vapour treatment decreases by 88 per cent. This research has been conducted to provide a better method to treat PLA parts using chemical reagents.

  18. Advanced Surface Polishing For Accelerator Technology Using Ion Beams

    Science.gov (United States)

    Insepov, Z.; Norem, J.; Hassanein, A.; Wu, A. T.

    2009-03-01

    A gas cluster ion beam (GCIB) technology was successfully applied to surface treatment of Cu, stainless steel, Ti, and Nb samples and to Nb rf-cavities by using accelerated cluster ion beams of Ar, O2 and combinations of them, with accelerating voltages up to 35 kV. DC field emission (dark current) measurements and electron microscopy were used to investigate metal surfaces treated by GCIB. The experimental results showed that GCIB technique can significantly reduce the number of field emitters and can change the structure of the Nb oxide layer on the surface. The RF tests of the GCIB-treated Nb rf-cavities showed improvement of the quality factor Q at 4.5 K. The superconducting gap was also enhanced by using the oxygen GCIB irradiation exposure.

  19. Industrial characterization of nano-scale roughness on polished surfaces

    DEFF Research Database (Denmark)

    Feidenhans'l, Nikolaj Agentoft; Hansen, Poul-Erik; Pilny, Lukas

    2015-01-01

    We report a correlation between the scattering value “Aq” and the ISO standardized roughness parameter Rq. The Aq value is a measure for surface smoothness, and can easily be determined from an optical scattering measurement. The correlation equation extrapolates the Aq value from a narrow measur...

  20. Efficacy of Polishing Kits on the Surface Roughness and Color ...

    African Journals Online (AJOL)

    2017-05-22

    May 22, 2017 ... [8]. The. Address for correspondence: Dr. H Gumus,. Department of Pedodontics, Faculty of Dentistry, .... for 5 min and then blotted with dry tissue paper before color measurements were taken.[1] The ..... of a modeling resin and thermocycling on the surface hardness, roughness, and color of different resin ...

  1. Effects of polishing on surface roughness, gloss, and color of resin composites.

    Science.gov (United States)

    Hosoya, Yumiko; Shiraishi, Takanobu; Odatsu, Tetsuro; Nagafuji, Junichi; Kotaku, Mayumi; Miyazaki, Masashi; Powers, John M

    2011-09-01

    This study evaluated the effects of polishing on surface roughness, gloss, and color of regular, opaque, and enamel shades for each of three resin composites. Two-mm-thick resin disks made with Estelite Σ Quick, Clearfil Majesty, and Beautifil II were final polished with 180-, 1000-, and 3000-grit silicon carbide paper. Surface roughness, gloss, and color were measured one week after curing. Estelite Σ Quick had significantly lower roughness values and significantly higher gloss values as compared with Clearfil Majesty and Beautifil II. The effects of surface roughness and gloss on color (L*a*b*) differed among resin composites and by shade. Correlation coefficients between surface roughness and L*a*b* color factors were generally high for Clearfil Majesty, partially high (i.e., between roughness and L*) for Beautifil II, and low for Estelite Σ Quick. Correlation coefficients between gloss and L*a*b* color parameters were generally high for Beautifil II and low for Estelite Σ Quick and Clearfil Majesty. However, for all resin composites, the values of the color differences between 3000-grit and 180-grit polishing groups for all shades were imperceptible by the naked eye.

  2. Effect of different polishing methods on surface roughness of provisional prosthetic materials.

    Science.gov (United States)

    Tupinambá, Ívian Verena Maia; Giampá, Priscila Couy Corrêa; Rocha, Isadora Almeida Rios; Lima, Emilena Maria Castor Xisto

    2018-01-01

    To evaluate the surface roughness of bis-acrylic and acrylic resins submitted to different methods of polishing. Fifty samples of each provisional restorative material (Structur 2, Protemp 4, Duralay, and Dencrilay) were fabricated (10 mm × 2 mm) and divided into five groups ( n = 10): (1) positive control group - polyester strip; (2) negative control - unpolished; (3) abrasive tips (Exa-Technique-Edenta); (4) goat hair brush and diamond polishing paste; and (5) silicone tips (Enhance). Each material was mixed and polymerized according to manufacturer's instructions. The parameter evaluated was the arithmetic mean of the surface roughness (Ra) determined using the rugosimeter SJ 301 (Mitutoyo, Japan). The data were analyzed with two-way analysis of variance ( post hoc Tukey's test) ( P < 0.05). The lowest surface roughness values (0,22-0,90 μm) were observed in the Group 4 - goat hair brush and diamond paste, while the highest values (1,17-1,44 μm) were found in the Group 5 - silicone tips (enhance), with statistically significant differences between them, except for Dencrilay acrylic resin. There was statistically significant difference between bis-acrylic and acrylic resins in the Groups 1, 2, and 4. Within the limitations of this study, it was concluded that the most effective polishing system was the goat hair brush with diamond paste for both bis-acrylic and acrylic resins. The bis-acrylic resins exhibited significantly smoother surfaces than the acrylic resins.

  3. Bacteria contamination of touch surfaces in Polish hospital wards

    Directory of Open Access Journals (Sweden)

    Anna Różańska

    2017-08-01

    Full Text Available Background: The objective of the study has been to evaluate the pathogenic bacteria contamination of touch surfaces in hospital wards. Material and Methods: Samples were taken from frequently touched surfaces in the hospital environment in 13 units of various types. Culturing was carried out on solid blood agar and in growth broth (tryptic soy broth – TSB. Species identification was performed using the analytical profile index (API biochemical testing and confirmed with matrix assisted laser desorption ionization time-flight mass spectrometry (MALDI-TOF-MS system. Results: The total of 161 samples were taken for the study. Fifty-two of them, after 24 h of culture on a solid medium, demonstrated bacterial growth and further 60 samples had growth after prior multiplication in TSB. Overall, 69.6% of samples exhibited growth of 19 bacterial species. Pathogenic species – representing indicator organisms of efficiency of hospital cleaning – was demonstrated by 21.4% of samples. Among them Acinetobacter spp., Enterocococci spp. and Staphylococcus aureus were identified. Coagulase-negative staphylococci (CNS were predominant. The proportion of various groups of bacteria significantly varied in respective hospitals, and in various types of wards. Disturbing observation is a large proportion of resistance of isolated CNS strains as a potential reservoir of resistance genes. Conclusions: The results show that touch surfaces in hospital units are contaminated by both potentially pathogenic and pathogenic bacterial species. In connection with the reported, also in Poland, frequent omission or incorrect execution of hand hygiene by hospital staff, and probably patients, touch surfaces still constitute important reservoir of pathogenic bacteria. Improving hand hygiene compliance of health-care workers with recommendations is necessary for increasing biological safety of hospital environment. Med Pr 2017;68(3:459–467

  4. Polishing Metal Mirrors to 0,025 Micron Surface Finish

    DEFF Research Database (Denmark)

    Pedersen, P. E.

    1978-01-01

    A research program undertaken by the Danish Atomic Energy Commission required the fabrication of metal mirrors measuring 1 m long by 53 mm wide, which had to be finished to extremely tight tolerances on thickness, plane-parallelism and surface characteristics. Progressively finer diamond compounds...... are employed to achieve a high gloss finish on the metal mirrors, which are used in polarized neutron experiments. This article describes the fabrication techniques developed at the Commission's Ris phi Central Workshop....

  5. The Effect of Prophylactic Polishing Pastes on Surface Roughness of Indirect Restorative Materials

    Directory of Open Access Journals (Sweden)

    Esra Can Say

    2014-01-01

    Full Text Available The purpose of this study was to evaluate the influence of prophylactic polishing pastes (PPP; Detartrine (DT, Topex (TP on surface roughness (Ra of indirect composites (IRC; Tescera (TES, Gradia (GRD, and Estenia C&B (EST, a glass ceramic (Empress 2 layering (E2, and a leucite reinforced glass ceramic (Empress Esthetic (EE with two different (glazed (G; polished (P surface preparations. A total of 90 IRC and 120 ceramic discs, 8 mm in diameter and 2 mm thick, were prepared. E2 and EE specimens were randomly divided into two groups (n=30. One group was glazed (GE2; GEE, while the other group was polished (PE2; PEE the same as the IRCs. The specimens in each group were subsequently divided into three subgroups: control (C, DT, and TP. Ra (μm was evaluated with a profilometer. Data were analyzed by Kruskal Wallis, followed by the Dunn's multiple comparison tests P0.05. PE2 and PEE were not affected by DT or TP P>0.05, while GE2 and GEE exhibited significant roughening after TP P<0.05. Surface roughness of IRCs and glazed ceramics can be affected by PPP applications.

  6. APPLICATION OF CHEMICAL PRE-TREATMENT ON THE POLISHED SURFACE OF ALUMINIUM ALLOYS

    Directory of Open Access Journals (Sweden)

    Pavel Kraus

    2016-12-01

    Full Text Available This paper reports the preparation and characterization of thin transparent nanolayers with phase composition ZrF4 and different modification of SiO2 with special focus on affecting the surface roughness of the material and the way of exclusion of the thin nanolayer on the surface of the polished aluminium material. The thin nanolayer was prepared by the sol-gel method. The final treatment based on PTFE was applied on the surface of some samples. This treatment is suitable for increasing wear resistance. The films were characterized with help of SEM microscopy and EDS analysis. The surface roughness was measured with classical surface roughness tester. The results on this theme have already published but not on the polished surface of the aluminium material. The results from the experiment show the problems with application of these nanolayers because a cracks were found on the surface of the material and deformations of the layer after application of the PTFE final layer. The surface layer formation is discussed.

  7. Surface alloying of aluminum with molybdenum by high-current pulsed electron beam

    Science.gov (United States)

    Xia, Han; Zhang, Conglin; Lv, Peng; Cai, Jie; Jin, Yunxue; Guan, Qingfeng

    2018-02-01

    The surface alloying of pre-coated molybdenum (Mo) film on aluminum (Al) substrate by high-current pulsed electron beam (HCPEB) was investigated. The microstructure and phase analysis were conducted by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results show that Mo particles were dissolved into Al matrix to form alloying layer, which was composed of Mo, Al and acicular or equiaxed Al5Mo phases after surface alloying. Meanwhile, various structure defects such as dislocation loops, high-density dislocations and dislocation walls were observed in the alloying surface. The corrosion resistance was tested by using potentiodynamic polarization curves and electrochemical impedance spectra (EIS). Electrochemical results indicate that all the alloying samples had better corrosion resistance in 3.5 wt% NaCl solution compared to initial sample. The excellent corrosion resistance is mainly attributed to the combined effect of the structure defects and the addition of Mo element to form a more stable passive film.

  8. Effects of surface polishing and annealing on the optical conductivity of intermetallic compounds

    International Nuclear Information System (INIS)

    Rhee, Joo Yull

    1999-01-01

    The optical conductivity spectra of several intermetallic compounds were measured by spectroscopic ellipsometry. Three spectra were measured for each compound; just after the sample was mechanically polished, at high temperature, and after the sample was annealed at 110 .deg. C for at least one day and cooled to room temperature. An equiatomic FeTi alloy showed the typical effects of annealing after mechanical polishing of surface. The spectrum after annealing had a larger magnitude and sharper structures than the spectrum before annealing. We also observed shifts of peaks in the spectrum. A relatively low-temperature annealing gave rise to unexpectedly substantial effects, and the effects were explained by recrystallization and/or a disorder → order transition of the surface of the sample which was damaged and, hence, became highly disordered by mechanical polishing. Similar effects were also observed when the sample temperature was lowered. The observed changes upon annealing could partly be explained by presumption that the recrystallization would be realized in such a way that the average atomic spacing would be reduced

  9. An in vivo evaluation of surface polishing of TAN intermedullary nails for ease of removal

    Directory of Open Access Journals (Sweden)

    JS Hayes

    2009-09-01

    Full Text Available Fractures of the tibia and femoral diaphysis are commonly repaired by intra-medullary (IM nailing. Currently IM nails are available in either electropolished stainless steel (SS or in Titanium-Aluminium-Niobium (TAN. After healing, removal of the nails still is common but removal of TAN IM nails often has complications whereas SS IM nails of the same design are less often associated with problems. We believe the differences in removal are due to the ability of TAN to promote strong bone on-growth. We have previously shown in vivo that polishing cortical screws reduces removal torque and the percentage of bone-implant contact. Therefore, we postulate that bony on-growth onto IM nails can be reduced by means of surface polishing, for ease of removal. Here we aim to compare the pull-out forces for removal of standard TAN (TAN-S compared to experimental paste polished TAN (TAN-PP IM nails from a bilateral non-fracture sheep tibia model after 12 months implantation. Histological analysis was also performed to assess tissue on-growth to the nails. We show that polishing significantly reduces (p=0.05 the extraction force required for TAN IM nail removal. This effect in part is attributable to the distinct tissue-material reaction produced. For TAN-S nails direct bone contact was observed while for TAN-PP nails a fibrous tissue interface was noted. Since TAN is preferred over SS for IM nailing due to superior biocompatibility and mechanical properties, we believe these findings could be used to recommend changes to current surface technologies of intramedullary nails to reduce complications seen with nail removal especially in rapidly growing bone in children.

  10. The effect of scattered light sensor orientation on roughness measurement of curved polished surfaces

    DEFF Research Database (Denmark)

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

    with crossed surface lay to document the robustness of the method. The instrument area-integrating measuring principle (figure 1) is based on a non-coherent light beam of ∅ 0.9 mm and 670 nm wavelength illuminating the measured surface, reflection of the incident light from the surface slopes in spatial......The effect of angular orientation of a scattered light sensor with respect to main curvature and surface lay on roughness measurements is evaluated. A commercial scattered light sensor OS 500-32 from Optosurf GmbH was used. The investigation was performed on polished cylindrical surfaces...... directions, and its acquisition within ± 16º angular range with a linear detector array. From the distribution of the acquired scattered light intensity, a number of statistical parameters describing the surface texture are calculated, where the Aq parameter (variance of the scattered light distribution...

  11. Effects of Delayed Finishing/Polishing on Surface Roughness, Hardness and Gloss of Tooth-Coloured Restorative Materials

    Science.gov (United States)

    Yazici, A. Ruya; Tuncer, Duygu; Antonson, Sibel; Onen, Alev; Kilinc, Evren

    2010-01-01

    Objectives: The aim of this study was to investigate the effect of delayed finishing/polishing on the surface roughness, hardness and gloss of tooth-coloured restorative materials. Methods: Four different tooth-coloured restoratives: a flowable resin composite- Tetric Flow, a hybrid resin composite- Venus, a nanohybrid resin composite- Grandio, and a polyacid modified resin composite- Dyract Extra were used. 30 specimens were made for each material and randomly assigned into three groups. The first group was finished/polished immediately and the second group was finished/polished after 24 hours. The remaining 10 specimens served as control. The surface roughness of each sample was recorded using a laser profilometer. Gloss measurements were performed using a small-area glossmeter. Vickers microhardness measurements were performed from three locations on each specimen surface under 100g load and 10s dwell time. Data for surface roughness and hardness were analyzed by Kruskal Wallis test and data for gloss were subjected to one-way ANOVA and Tukey test (P Grandio samples showed significantly higher roughness than the delayed polished samples (P .05). The lowest hardness values were found under Mylar strip. Delayed finishing/polishing significantly increased the hardness of all materials. Conclusions: The effect of delayed finishing/polishing on surface roughness, gloss and hardness appears to be material dependent. PMID:20046480

  12. Mirror-smooth surfaces and repair of defects in superconducting RF cavities by mechanical polishing

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, C. A. [Fermilab; Cooley, L. D. [Fermilab

    2012-11-22

    Mechanical techniques for polishing the inside surface of niobium superconducting radio-frequency (SRF) cavities have been systematically explored. By extending known techniques to fine polishing, mirror-like finishes were produced, with <15 nm RMS (root mean square) roughness over 1 mm2 scan area. This is an order of magnitude less than the typical roughness produced by the electropolishing of niobium cavities. The extended mechanical polishing (XMP) process was applied to several SRF cavities which exhibited equator defects that caused quench at <20 MV m-1 and were not improved by further electropolishing. Cavity optical inspection equipment verified the complete removal of these defects, and minor acid processing, which dulled the mirror finish, restored performance of the defective cells to the high gradients and quality factors measured for adjacent cells when tested with other harmonics. This innate repair feature of XMP could be used to increase manufacturing yield. Excellent superconducting properties resulted after initial process optimization, with quality factor Q of 3 × 1010 and accelerating gradient of 43 MV m-1 being attained for a single-cell TESLA cavity, which are both close to practical limits. Several repaired nine-cell cavities also attained Q > 8 × 109 at 35 MV m-1, which is the specification for the International Linear Collider. Future optimization of the process and pathways for eliminating requirements for acid processing are also discussed.

  13. The Influence of Surface Polish and Beverages on the Roughness of Nanohybrid and Microhybri Resin Composites

    Directory of Open Access Journals (Sweden)

    Sadeghi M

    2016-03-01

    Full Text Available Statement of the Problem: Surface roughness is a key factor in the aesthetics of restorative dentistry as it can determine the clinical quality and success of restorative materials. The chemical process of dissolution in the presence of mechanical forces can accelerate the surface roughness of tooth-coloured restorative materials. Objectives: To determine the degree of surface roughness of a microhybrid and a nanohybrid resin composite after polishing and immersion in various solutions. Materials and Methods: Two resin composites were used : a microhybrid (Gradia direct, GC, and a nanohybrid (Ice, SDI. A total of 54 disc-shaped specimens were prepared for each composite and immersed in distilled water incubated at 37 °C for 24 hours. After 24 h, the baseline measurement for surface roughness (Ra was performed and the specimens were divided into 3 groups of 18 and tested with unpolished or after polishing with Sof-Lex disc and Enhance point systems. Specimens in each group were subdivided into 3 subgroups (n = 6 and immersed in 3 solutions (distilled water, coffee, and cola for 7 days incubated at 37 °C. After 7 days, the specimens were rinsed with tap water for 10 seconds, dried with paper towel and Ra was measured again. Two randomly selected specimens of each group were sputter coated with gold and examined using a Field-Emission Scanning Electron Microscope (SEM. Results: Gradia direct showed a greater Ra than ice in all solutions for all polishing systems (p < 0.001. Specimens polished with Enhance point revealed a significantly greater roughness than Sof-Lex discs and both showed greater Ra than unpolished specimens. Specimens immersed in coffee exhibited significantly greater surface roughness than that of distilled water (p < 0.05 and cola (p < 0.001. Conclusions: Nano-hybrid composite showed a significantly smoother surface than microhybrid. Coffee exhibited the highest Ra compared to distilled water and cola. Enhance point revealed

  14. CO/sub 2/-laser polishing of fused silica surfaces for increased laser damage resistance at 1. 06. mu. m

    Energy Technology Data Exchange (ETDEWEB)

    Temple, P.A.; Milam, D.; Lowdermilk, W.H.

    1980-04-03

    Bare fused silica surfaces were prepared by subjecting the mechanically polished surface to a rastered cw CO/sub 2/ laser beam. Analysis shows that this processing causes: (a) removal of a uniform layer of fused silica; and (b) a probable re-fusing or healing of existing subsurface fractures. The fused silica removal rate is found to be a function of the laser intensity and scan rate. These surfaces are seen to have very low scatter and to be very smooth. In addition, they have exhibited entrance surface damage thresholds at 1.06 ..mu..m, and 1 nsec, which are substantially above those seen on the mechanically polished surface. When damage does occur, it tends to be at a few isolated points rather than the general uniform damage seen on the mechanicaly polished part. In addition to the damage results, we will discuss an observational technique used for viewing these surfaces which employs dark-field illumination.

  15. EVALUATION OF SURFACE CONDITION AFTER FINISHING AND POLISHING OF A FLOWABLE COMPOSITE MATERIAL

    Directory of Open Access Journals (Sweden)

    Bogdan MUNTEANU

    2016-06-01

    Full Text Available The aim of the study was to evaluate the surface condition, after finishing and polishing with 3 different systems, of a flowable composite material, starting from the microstructure experimentally analyzed by atomic force microscopy. Materials and method. The material tested in the present study was Filtek Ultimate Flowable Restorative (3M ESPE composite. 20 cylindrical samples, 5 mm in diameter and 2 mm thick, were prepared by using metallic molds. The samples were randomly divided into 4 groups: a group containing 5 control samples, not subjected to finishing and 3 groups formed, each, of 5 samples for each of the three finishing and polishing systems, respectively system 1: the two-step Sof-Lex (3M ESPE, system 2: multistep Super Snap (Shofu, Inc. Kyoto, Japan and system 3: multi-step OptiDisc (KerrHawe SA, Switzerland. The surfaces of the samples were analyzed by atomic force microscopy. For quantitative evaluations, the rugosity parameter (Ra, and the mean deviation of the determined profile were calculated. Results. All 3 polishing systems determined an increase of the Ra parameter, comparatively with the control samples; the highest mean Ra value, of 1.19 µm, was recorded for system 3, followed by system 2 (mean Ra value = 1.12 µm, while the lowest mean value, of 1.10 µm, was registered for system 1. Conclusions. All three systems under investigation induced increased rugosity on the surfaces of the samples prepared from the Filtek Ultimate Flowable Restorative (3M ESPE composite resin. The most abrasive system appears to be OptiDisc (KerrHawe SA, Switzerland, followed by the Super Snap (Shofu, Inc. Kyoto, Japan system, the one recording the lowest abrasion being SofLex (3M ESPE.

  16. Negentropy Generation and Fractality in the Dry Friction of Polished Surfaces

    Directory of Open Access Journals (Sweden)

    Mordecai Segall

    2010-03-01

    Full Text Available We consider the Robin Hood model of dry friction to study entropy transfer during sliding. For the polished surface (steady state we study the probability distribution of slips and find an exponential behavior for all the physically relevant asperity interaction-distance thresholds. In addition, we characterize the time evolution of the sample by its spatial fractal dimension and by its entropy content. Starting from an unpolished surface, the entropy decreases during the Robin Hood process, until it reaches a plateau; thereafter the system fluctuates above the critical height. This validates the notion that friction increases information in the neighborhood of the contacting surface at the expense of losing information in remote regions. We explain the practical relevance of these results for engineering surface processing such as honing.

  17. Effect of conditioner load on the polishing pad surface during chemical mechanical planarization process

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Cheol Min; Qin, Hong Yi; Hong, Seok Jun; Jeon, Sang Hyuk; Kulkarni, Atul; Kim, Tae Sun [Sungkyunkwan University, Suwon (Korea, Republic of)

    2016-12-15

    During the Chemical mechanical planarization (CMP), the pad conditioning process can affect the pad surface characteristics. Among many CMP process parameters, the improper applied load on the conditioner arm may have adverse effects on the polyurethane pad. In this work, we evaluated the pad surface properties under the various conditioner arm applied during pad conditioning process. The conditioning pads were evaluated for surface topography, surface roughness parameters such as Rt and Rvk and Material removal rate (MRR) and within-wafer non-uniformity after wafer polishing. We observed that, the pad asperities were collapsed in the direction of conditioner rotation and blocks the pad pores applied conditioner load. The Rvk value and MRR were founded to be in relation with 4 > 1 > 7 kgF conditioner load. Hence, this study shows that, 4 kgF applied load by conditioner is most suitable for the pad conditioning during CMP.

  18. PITTING CORROSION OF AISI 316Ti STAINLESS STEEL WITH POLISHED SURFACE

    Directory of Open Access Journals (Sweden)

    Viera Zatkalíková

    2010-05-01

    Full Text Available AISI 316Ti is Cr–Ni–Mo austenitic stainless steel with the high Pitting Resistance Equivalent Number (PREN. The effect of the surface finishing by polishing on the pitting corrosion resistance was tested in aggressive 5% FeCl3 solution. The immersion tests were curried out at the temperature 30, 50, 80 °C. The electrochemical cyclic potentiodynamic tests were carried out in the same solution at temperature 30 and 50 °C. The evaluation of the corrosion resistance arose from the comparison of the results of the immersion and the cyclic potentiodynamic tests.

  19. Characterisation and stabilisation of the surface region of a highly polished silicon crystal sphere

    International Nuclear Information System (INIS)

    Kenny, M.J.; Wielunski, L.S.

    1999-01-01

    Full text: Typically a single crystal silicon wafer has a native oxide layer a few nm thick which changes slowly with time. A number of parameters such as hydrocarbons, water vapour, storage environment can affect this layer. The thickness of the layer is also orientation dependent. In the case of a silicon sphere the situation becomes more complex, because all orientations are present and the process of polishing involves a higher pressure and also high local temperatures. A highly polished single crystal sphere 93.6 mm in diameter is being used to determine the Avogadro constant with an uncertainty of ≤ 1 x 10 -8 . This will then be used to obtain an atomic definition of the kilogram. The composition and structure of the surface oxide layer play an important role in this measurement. Firstly the density of the oxide layer is different from that of silicon. Secondly since the diameter is measured by optical interferometry, corrections must be applied for the phase change in the reflected light beam due to the surface layer. Thirdly the orientation dependence of the layer complicated the corrections to be applied. Fourthly if measurements are made over a period of time, any changes in the surface layer must be taken into account. Given the accuracy required in the determination, the surface layer is a determining factor in the final result. A number of techniques such as spectroscopic ellipsometry and ion beam analysis are being used to study the composition and structure of the surface of a silicon sphere. Cleaning techniques such as HF and low temperature ultraviolet (ozone) are being developed to produce a clean surface. The next step involves deposition of a stable and uniform surface oxide layer a few nm thick. Techniques being investigated for this include ultra violet ozone deposition at 450 deg C and plasma deposition. The paper describes work at the NML in achieving an appropriate stable surface on the silicon sphere

  20. Impact of Surface Treatment on the Structural and Electronic Properties of Polished CdZnTe Surfaces for Radiation Detectors

    Science.gov (United States)

    Tari, Suleyman; Aqariden, F.; Chang, Y.; Grein, C.; Li, Jin; Kioussis, N.

    2013-11-01

    We present the effects of surface treatments on the structural and electronic properties of chemomechanically polished Cd0.9Zn0.1Te before contact deposition. Specifically, polished CdZnTe (CZT) samples were treated with four distinct chemical etchants: (1) bromine methanol (BM), (2) bromine in lactic acid, (3) bromine in methanol followed by bromine-20% lactic acid in ethylene glycol, and (4) hydrochloric acid (HCl). The surface structure and surface electronic properties were studied with atomic force microscopy (AFM) and x-ray photoelectron spectroscopy (XPS). AFM images showed that three of the four etchants significantly altered the surface morphology and structure of CZT. All etchants created smoother surfaces; however, all except HCl also introduced high densities of defects. HCl was found to not affect the surface structure. XPS measurements indicated that a thick, ˜3 nm to 4 nm, TeO2 layer formed about 1 h after etching; hence, it is very important to process devices immediately after etching to prevent oxide formation.

  1. Surface Roughness, Microhardness, and Microleakage of a Silorane-Based Composite Resin after Immediate or Delayed Finishing/Polishing

    Directory of Open Access Journals (Sweden)

    Fernanda Carvalho Rezende Lins

    2016-01-01

    Full Text Available Objective. This study evaluated the effect of immediate or delayed finishing/polishing using different systems on the surface roughness, hardness, and microleakage of a silorane-based composite. Material and Methods. Specimens were made with silorane-based composite (Filtek P90, 3M ESPE and assigned to the treatments: control (light-cured; aluminum oxide discs (Sof-Lex, 3M ESPE; diamond-impregnated silicone tips (Astropol, Ivoclar Vivadent; aluminum oxide-impregnated silicone tips (Enhance, Dentsply. Half of the specimens were finished/polished immediately and the rest after 7 days. Surface roughness (Ra, μm; n=20 and Vickers microhardness (50 g; 45 s; n=10 were measured. Cavities were prepared in bovine incisors and filled with Filtek P90. The fillings received immediate or delayed finishing/polishing (n=10 and were subjected to dye penetration test (0.5% basic fuchsin, 24 h. Data were analyzed by ANOVA and Scheffe, Kruskal-Wallis, and Mann-Whitney tests (p<0.05. Results. The finishing/polishing system significantly influenced roughness and microhardness (p<0.0001. For enamel, microleakage was not affected by the finishing/polishing system (p=0.309. For dentin, Sof-Lex discs and Astropol points promoted greater microleakage than Enhance points (p=0.033. Conclusion. Considering roughness, microhardness, and microleakage together, immediate finishing/polishing of a silorane-based composite using aluminum oxide discs may be recommended.

  2. Effect of two different polishing systems on fluoride release, surface roughness and bacterial adhesion of newly developed restorative materials.

    Science.gov (United States)

    Bayrak, Gokcen Deniz; Sandalli, Nuket; Selvi-Kuvvetli, Senem; Topcuoglu, Nursen; Kulekci, Guven

    2017-11-12

    To evaluate the effects of two different polishing systems on fluoride release, surface roughness and bacterial adhesion of five restorative materials MATERIALS AND METHODS: The study groups were comprised of five different restorative materials, Beautifil II (B); GCP Glass Fill (G); Amalgomer CR (A); Dyract XP (D); Fuji IX GP (F) and 21 specimens were prepared from each material. Each group was divided into three subgroups according to the polishing system: Mylar (control) (C), Sof-lex (S), and Enhance-Pogo (EP). The amount of fluoride release was measured using a fluoride ion-selective electrode and surface roughness was investigated with a profilometer. Bacterial adhesion on the materials was evaluated by optical density readouts for S.mutans on a spectrophotometer. The highest amount of fluoride was released from specimens in the S subgroup of group G during all measurement days. Surface roughness values were significantly lower in subgroup C than the other polishing systems in all study groups except group G (P restorative materials especially in glass ionomer-based materials. This article stated that polishing promoted a significant increase of fluoride release on restorative materials especially in glass ionomer-based materials. Further, proper polishing systems must be chosen according to the structure and composition of materials to provide the best clinical benefits in terms of fluoride release, surface roughness and bacterial adhesion. © 2017 Wiley Periodicals, Inc.

  3. Molybdenum and tungsten disulfides surface-modified with a conducting polymer, polyaniline, for application in electrorheology

    Czech Academy of Sciences Publication Activity Database

    Stejskal, Jaroslav; Mrlík, M.; Plachý, T.; Trchová, Miroslava; Kovářová, Jana; Li, Yu

    2017-01-01

    Roč. 120, November (2017), s. 30-37 ISSN 1381-5148 R&D Projects: GA ČR(CZ) GA17-04109S Institutional support: RVO:61389013 Keywords : molybdenum sulfide * polyaniline * conducting polymer Subject RIV: CD - Macromolecular Chemistry OBOR OECD: Polymer science Impact factor: 3.151, year: 2016

  4. Evaluation of enamel surfaces following interproximal reduction and polishing with different methods: A scanning electron microscope study

    Directory of Open Access Journals (Sweden)

    Eenal Bhambri

    2017-01-01

    Full Text Available Background: Interproximal reduction was introduced as an alternative to tooth extraction in patients with mild-to-moderate crowding, the beneficial outcomes of interdental reduction have been well documented, but nevertheless, possible detrimental effects on enamel have also been an issue of debate. Interproximal reduction generates the formation of grooves and valleys creating plaque retentive areas, predisposing teeth to caries, and periodontal disease. Various proximal stripping techniques, it is postulated, produce varying grades of roughness of the enamel surface; it is in this area that the research in this paper was focused. Aim: The aim is to evaluate enamel surface roughness after various interproximal reduction and polishing methods. Materials and Methods: 16-blade tungsten carbide bur, diamond disc, diamond-coated metal strip, fine Sof-Lex disc, and fine diamond bur were used for interproximal reduction and polishing on extracted human premolars. The specimens were then evaluated under scanning electron microscope (SEM and surface plots of images were made using Image J software. Statistical Analysis: The data obtained were subjected to ANOVA and posthoc multiple tests. Results: Under the SEM, all interproximal reduction protocols resulted in roughened and grooved enamel surfaces. The use of diamond-coated metal strip followed by polishing with fine Sof-Lex disc created surfaces that were reasonably smooth. Conclusions: The enamel surfaces after reduction with diamond-coated metal strip and polishing by fine Sof-Lex disc (group F were the smoothest.

  5. Effects of surface orientation, fluid chemistry and mechanical polishing on the variability of dolomite dissolution rates

    Science.gov (United States)

    Saldi, Giuseppe D.; Voltolini, Marco; Knauss, Kevin G.

    2017-06-01

    Recent studies of carbonate surface reactivity have underscored the fundamental variability of dissolution rates and the heterogeneous distribution of the reaction over the mineral surface due to the inhomogeneous distribution of surface energy. Dolomite dissolution rates relative to different cleavage planes (r-planes) and surfaces cut approximately perpendicular to the c-axis (c-planes) were studied at 50 °C as a function of pH (3.4 ≤ pH ≤ 9.0) and solution composition by vertical scanning interferometry (VSI) and atomic force microscopy (AFM), with the aim of providing an estimate of the intrinsic rate variation of dolomite single crystals and describing the surface reaction distribution and the rate controlling mechanisms. Surface normal retreat rates measured under acidic conditions increased linearly with time and were not visibly affected by the parallel increase of surface roughness. Mean total dissolution rates of r-planes decreased by over 200 times from pH 3.4 to pH 9.0 and CO32--rich solutions, whereas corresponding rate variations spanned over 3 orders of magnitude when also c-plane rate distributions were included in the analysis. At acid to near neutral pH, c-planes dissolved ∼ three times faster than the adjoining r-planes but slower at basic pH and high total carbon concentration, displaying a distinctive morphologic evolution in these two regimes. The comparison of polished and unpolished crystals showed that polished cleavage planes dissolved about three times faster than the unpolished counterpart at near neutral to basic conditions, whereas no significant difference in reactivity was observed at pH < 5. Although experimental data and observations indicate a tendency of dolomite faces to reach a low-energy topography over the course of the reaction, the evolution of the entire crystal morphology depends also on the reactivity of edge and corner regions, whose contribution to measured rates is not generally taken into account by laboratory

  6. Wear of Polished Steel Surfaces in Dry Friction Linear Contact on Polimer Composites with Glass Fibres

    Directory of Open Access Journals (Sweden)

    D. Rus

    2013-12-01

    Full Text Available It is generally known that the friction and wear between polymers and polished steel surfaces has a special character, the behaviour to friction and wear of a certain polymer might not be valid for a different polymer, moreover in dry friction conditions. In this paper, we study the reaction to wear of certain polymers with short glass fibres on different steel surfaces, considering the linear friction contact, observing the friction influence over the metallic surfaces wear. The paper includes also its analysis over the steel’s wear from different points of view: the reinforcement content influence and tribological parameters (load, contact pressure, sliding speed, contact temperature, etc.. Thus, we present our findings related to the fact that the abrasive component of the friction force is more significant than the adhesive component, which generally is specific to the polymers’ friction. Our detections also state that, in the case of the polyamide with 30% glass fibres, the steel surface linear wear rate order are of 10-4 mm/h, respectively the order of volumetric wear rate is of 10-6 cm3 /h. The resulting volumetric wear coefficients are of the order (10-11 – 10-12 cm3/cm and respectively linear wear coefficients of 10-9 mm/cm.

  7. Effect of Irradiation Parameters on Morphology of Polishing DF2 (AISI-O1 Surface by Nd:YAG Laser

    Directory of Open Access Journals (Sweden)

    Wei Guo

    2007-01-01

    Full Text Available Pulse Nd:YAG laser was used to polish DF2 cold work steel. Influence of irradiation parameters on the 3D surface morphology was studied by 3D profilometer, scanning electron microscopy (SEM, and atomic force microscope (AFM. Results among the tests showed when DF2 specimens were irradiated with parameters of (i laser input energy P=1 J, (ii pulse feedrate=300 mm/min, (iii pulse duration (PD =3 milliseconds, and (iv pulse frequency f=20∼25 Hz, laser polishing of DF2 cold work steel seemed to be successful.

  8. Model of smoothing roughness on GaAs wafer surface by using nonabrasive chemical-and-mechanical polishing

    Directory of Open Access Journals (Sweden)

    A.V. Fomin

    2017-04-01

    Full Text Available Studied experimentally in this work has been the process of smoothing relief roughness on the GaAs wafer surface by using the method of contactless nonabrasive chemical-and-mechanical polishing under conditions of its rotational movement relatively to the polishing plate. The model of this process has been developed under assumption that the pure diffusion smoothing mechanism takes place there. It has been shown that satisfactory correspondence between respective calculated dependences and experimental results can be reached by introducing the “effective” diffusion coefficient providing account of etchant convection.

  9. Well-Defined Molybdenum Oxo Alkyl Complex Supported on Silica by Surface Organometallic Chemistry: A Highly Active Olefin Metathesis Precatalyst

    KAUST Repository

    Merle, Nicolas

    2016-12-05

    The well-defined silica-supported molybdenum oxo alkyl species (SiO−)MoO(CH Bu) was selectively prepared by grafting of MoO(CH Bu)Cl onto partially dehydroxylated silica (silica) using the surface organometallic chemistry approach. This surface species was fully characterized by elemental analysis and DRIFT, solid-state NMR, and EXAFS spectroscopy. This new material is related to the active species of industrial supported MoO/SiO olefin metathesis catalysts. It displays very high activity in propene self-metathesis at mild (turnover number = 90 000 after 25 h). Remarkably, its catalytic performance outpaces those of the parent imido derivative and its tungsten oxo analogue.

  10. Well-Defined Molybdenum Oxo Alkyl Complex Supported on Silica by Surface Organometallic Chemistry: A Highly Active Olefin Metathesis Precatalyst.

    Science.gov (United States)

    Merle, Nicolas; Le Quéméner, Frédéric; Bouhoute, Yassine; Szeto, Kai C; De Mallmann, Aimery; Barman, Samir; Samantaray, Manoja K; Delevoye, Laurent; Gauvin, Régis M; Taoufik, Mostafa; Basset, Jean-Marie

    2017-02-15

    The well-defined silica-supported molybdenum oxo alkyl species (≡SiO-)MoO(CH 2 t Bu) 3 was selectively prepared by grafting of MoO(CH 2 t Bu) 3 Cl onto partially dehydroxylated silica (silica 700 ) using the surface organometallic chemistry approach. This surface species was fully characterized by elemental analysis and DRIFT, solid-state NMR, and EXAFS spectroscopy. This new material is related to the active species of industrial supported MoO 3 /SiO 2 olefin metathesis catalysts. It displays very high activity in propene self-metathesis at mild (turnover number = 90 000 after 25 h). Remarkably, its catalytic performance outpaces those of the parent imido derivative and its tungsten oxo analogue.

  11. Stainless steel surface alloying process with molybdenum or ruthenium by high-energy excimer laser: structural, electrochemical, and corrosion properties

    Science.gov (United States)

    Beaunier, Luc; Pasquier, Christian; Pillier, Francoise; Laurens, Patricia

    1997-08-01

    Chemical transformations on stainless steel surfaces (304 AISI) are obtained by melting with an excimer laser. The very high quenching rate allows to create a thin continuous metastable gradient in composition and structure by opposition to other melting techniques which promote multiphase layer. The mechanical properties of the bulk are maintained and the external layer is chemically modified for a better resistance to environmental aggressivity. Molybdenum is used for corrosion protection and ruthenium for cathodic and anodic properties. The composition is analyzed on cross-sections obtained by ultramicrotomy. A continuous gradient approximately 500 nm (nanometer) of Mo or Ru with decreasing grain size (304 AISI) is observed. Mo and Ru surface alloys show an important beneficial effect from cathodic and transpassive potential range.

  12. Rate equation model of bulk optical damage of silica, and the influence of polishing on surface optical damage of silica

    Science.gov (United States)

    Smith, Arlee; Do, Binh; Schuster, Rod; Collier, David

    2008-02-01

    Our objective is to understand the mechanism that generates catastrophic optical damage in pulsed fiber amplifiers. We measured optical damage thresholds of bulk fused silica at 1064 nm for 8 ns and 14 ps pulses. The 8 ns pulse is single longitudinal mode from a Q-switched laser, and the 14 ps pulse is from a Q-switched mode-lock laser. The beams in both cases are TEM 00 mode, and they are focused to a 7.5 μm spot inside a fused silica window. The pulse-to-pulse energy variations are 1% for 8 ns pulses and 5% for 14 ps pulses. Under these conditions optical damage is always accompanied by plasma formation at the focal spot; we found the damage threshold fluences are 3854 +/- 85 J/cm2 for the 8 ns pulses and 25.4 +/- 1.0 J/cm2 for the 14 ps pulses. These fluences are corrected for self focusing. Both damage thresholds are deterministic, in contrast to the claim often made in the literature that optical damage is statistical in the nanosecond range. The measured damage threshold fluences for 8 ns and 14 ps pulses do not fit a square root of pulse duration scaling rule. We interpret the damage in terms of plasma formation initiated by multiphoton ionization and amplified by an electron avalanche. The damage threshold irradiance can be matched with a simple rate equation model that includes multiphoton ionization, electron avalanche, and electron-hole recombination. The damage morphologies are dramatically different in the nanosecond and picosecond cases because of the large difference in deposited energy. However, both morphologies are reproducible from pulse to pulse. We also measured surface damage thresholds for silica windows polished by different methods. We find that cerium oxide polished surfaces damage at approximately 40% of the bulk threshold, with a large statistical spread. Surfaces prepared using an Al IIO 3 polish damaged between 50% and 100% of the bulk damage limit, with a substantial fraction at 100%. Surfaces polished using first the Al IIO 3 polish

  13. Characterization of wet pad surface in chemical mechanical polishing (CMP) process with full-field optical coherence tomography (FF-OCT).

    Science.gov (United States)

    Choi, Woo June; Jung, Sung Pyo; Shin, Jun Geun; Yang, Danning; Lee, Byeong Ha

    2011-07-04

    Chemical mechanical polishing (CMP) is a key process for global planarization of silicon wafers for semiconductors and AlTiC wafers for magnetic heads. Removal rate of wafer material is directly dependent on the surface roughness of a CMP pad, thus the structure of the pad surface has been evaluated with variable techniques. However, under in situ CMP process, the measurements have been severely limited due to the existence of polishing fluids including the slurry on the pad surface. In here, we newly introduce ultra-high resolution full-field optical coherence tomography (FF-OCT) to investigate the surface of wet pads. With FF-OCT, the wet pad surface could be quantitatively characterized in terms of the polishing pad lifetime, and also be three-dimensionally visualized. We found that reasonable polishing span could be evaluated from the surface roughness measurement and the groove depth measurement made by FF-OCT.

  14. Friction stir surfacing of cast A356 aluminium–silicon alloy with boron carbide and molybdenum disulphide powders

    Directory of Open Access Journals (Sweden)

    R. Srinivasu

    2015-06-01

    Full Text Available Good castability and high strength properties of Al–Si alloys are useful in defence applications like torpedoes, manufacture of Missile bodies, and parts of automobile such as engine cylinders and pistons. Poor wear resistance of the alloys is major limitation for their use. Friction stir processing (FSP is a recognized surfacing technique as it overcomes the problems of fusion route surface modification methods. Keeping in view of the requirement of improving wear resistance of cast aluminium–silicon alloy, friction stir processing was attempted for surface modification with boron carbide (B4C and molybdenum disulfide (MoS2 powders. Metallography, micro compositional analysis, hardness and pin-on-disc wear testing were used for characterizing the surface composite coating. Microscopic study revealed breaking of coarse silicon needles and uniformly distributed carbides in the A356 alloy matrix after FSP. Improvement and uniformity in hardness was obtained in surface composite layer. Higher wear resistance was achieved in friction stir processed coating with carbide powders. Addition of solid lubricant MoS2 powder was found to improve wear resistance of the base metal significantly.

  15. The improvement of surface roughness by polishing method of arcylic door panel at Taishi Tech Sdn Bhd

    Science.gov (United States)

    Basirin, Hammadi bin Mohd; Nawi, Ismail bin Haji Mohd

    2017-04-01

    This research is an approach to improve the surface roughness for acrylic door panel by using polishing process. The polishing process involve is sanding process by 3 types of sand paper. The sanding process used to improve the surface roughness by using the different grit sizes of sand paper. The experiment was done by using two types of material s, that is plywood and medium density board (MDF). These two materials are the main materials in producing the arcrylic door panel. The surface roughness of these two materials affects the qualities and quantities of the acrylic door panel. The surface structure was measured by using Optical Microscope and Scanning Electron Microscope (SEM) and the surface roughness was measured by using Mitutoyo surfest SJ 400 Tester. Results indicates that using the different types of grit are influence the surface roughness of the material. When the higher types of grit sizes had been used, the average roughness of the surface are decrease. In summary, a good surface roughness condition produced when using the higher types of grit sizes sand paper.

  16. Hydrogen Evolution Reaction Property in Alkaline Solution of Molybdenum Disulfide Modified by Surface Anchor of Nickel–Phosphorus Coating

    Directory of Open Access Journals (Sweden)

    Jun He

    2017-06-01

    Full Text Available Molybdenum disulfide (MoS2 is unfavorable for practical application in the hydrogen evolution reaction (HER process due to its inert basal surface, inferior conductivity, and limited amount of active edge sites. For the purpose of enhancing the HER performance of this catalyst, the HER activity of its basal surface should be increased. Herein, three types of nickel-phosphorus (Ni–P coatings—namely, low phosphorus (LP, medium phosphorus (MP and high phosphorus (HP —were anchored onto the surfaces of MoS2 nanoparticles via an electroless plating process; thus, three Ni–P/MoS2 composites (Ni–LP/MoS2, Ni–MP/MoS2, and Ni–HP/MoS2 were fabricated. Crystal structures, morphologies, chemical components, and HER performances of each in an alkaline solution were characterized. Both Ni–LP/MoS2 and Ni–MP/MoS2 showed a crystal nature, while the amorphous feature for Ni–HP/MoS2 was validated. The three Ni–P/MoS2 composites exhibited a higher HER activity than the pure MoS2. The HER performance of the Ni–MP/MoS2 composite was more outstanding than those of other two composites, which could be attributed to the presence of metastable nickel phosphides, and the excellent conductivity of Ni–MP coating anchored on the basal surface of MoS2.

  17. Influence of finishing/polishing on color stability and surface roughness of composites submitted to accelerated artificial aging

    Directory of Open Access Journals (Sweden)

    Gustavo Da Col dos Santos Pinto

    2013-01-01

    Full Text Available Aim: To assess the influence of finishing/polishing procedure on color stability (ΔE and surface roughness (Ra of composites (Heliomolar and Tetric - color A2 submitted to accelerated artificial aging (AAA. Materials and Methods : Sixty test specimens were made of each composite (12 mm × 2 mm and separated into six groups (n = 10, according to the type of finishing/polishing to which they were submitted: C, control; F, tip 3195 F; FF, tip 3195 FF; FP, tip 3195 F + diamond paste; FFP, tip 3195 FF + diamond paste; SF, Sof-Lex discs. After polishing, controlled by an electromechanical system, initial color (spectrophotometer PCB 6807 BYK GARDNER and Ra (roughness meter Surfcorder SE 1700, cut-off 0.25 mm readings were taken. Next, the test specimens were submitted to the AAA procedure (C-UV Comexim for 384 hours, and at the end of this period, new color readings and R a were taken. Results: Statistical analysis [2-way analysis of variance (ANOVA, Bonferroni, P < 0.05] showed that all composites demonstrated ΔE alteration above the clinically acceptable limits, with the exception of Heliomolar composite in FP. The greatest ΔE alteration occurred for Tetric composite in SF (13.38 ± 2.10 statistically different from F and FF (P < 0.05. For Ra , Group F showed rougher samples than FF with statistically significant difference (P < 0.05. Conclusion: In spite of the surface differences, the different finishing/polishing procedures were not capable of providing color stability within the clinically acceptable limits.

  18. Effect of ion-implantation on surface characteristics of nickel titanium and titanium molybdenum alloy arch wires

    Directory of Open Access Journals (Sweden)

    Manu Krishnan

    2013-01-01

    Full Text Available Aim: To evaluate the changes in surface roughness and frictional features of ′ion-implanted nickel titanium (NiTi and titanium molybdenum alloy (TMA arch wires′ from its conventional types in an in-vitro laboratory set up. Materials and Methods: ′Ion-implanted NiTi and low friction TMA arch wires′ were assessed for surface roughness with scanning electron microscopy (SEM and 3 dimensional (3D optical profilometry. Frictional forces were studied in a universal testing machine. Surface roughness of arch wires were determined as Root Mean Square (RMS values in nanometers and Frictional Forces (FF in grams. Statistical Analysis Used: Mean values of RMS and FF were compared by Student′s ′t′ test and one way analysis of variance (ANOVA. Results: SEM images showed a smooth topography for ion-implanted versions. 3D optical profilometry demonstrated reduction of RMS values by 58.43% for ion-implanted NiTi (795.95 to 330.87 nm and 48.90% for TMA groups (463.28 to 236.35 nm from controls. Nonetheless, the corresponding decrease in FF was only 29.18% for NiTi and 22.04% for TMA, suggesting partial correction of surface roughness and disproportionate reduction in frictional forces with ion-implantation. Though the reductions were highly significant at P < 0.001, relations between surface roughness and frictional forces remained non conclusive even after ion-implantation. Conclusion: The study proved that ion-implantation can significantly reduce the surface roughness of NiTi and TMA wires but could not make a similar reduction in frictional forces. This can be attributed to the inherent differences in stiffness and surface reactivity of NiTi and TMA wires when used in combination with stainless steel brackets, which needs further investigations.

  19. Molybdenum recovery

    International Nuclear Information System (INIS)

    Meyer, R.A.; Marquis, E.T.

    1992-01-01

    This patent describes a process for the preparation of propylene oxide and tertiary butyl alcohol. It comprises: propylene and tertiary butyl hydroperoxide are reacted in an epoxidation reaction zone in solution in tertiary butyl alcohol in the presence of a soluble molybdenum catalyst to provide an epoxidation reaction product comprising unreacted propylene, unreacted tertiary butyl hydroperoxide, propylene oxide, tertiary butyl alcohol, dissolved molybdenum catalyst and impurities, including lower aliphatic C 1 -C 4 carboxylic acids, and wherein the epoxidation reaction product is resolved into product fractions in a distillation zone including a distillate propylene fraction

  20. The effect of one-step and multi-step polishing systems on the surface roughness and microhardness of novel resin composites

    Science.gov (United States)

    Erdemir, Ugur; Sancakli, Hande Sar; Yildiz, Esra

    2012-01-01

    Objectives: The objective of this in vitro study was to evaluate the surface roughness and micro-hardness of three novel resin composites containing nanoparticles after polishing with one-step and conventional multi-step polishing systems. Methods: A total of 126 specimens (10 X 2 mm) were prepared in a metal mold using three nano-composites (Filtek Supreme XT, Ceram-X, and Grandio), 21 specimens of each resin composite for both tests (n=63 for each test). Following light curing, seven specimens from each group received no polishing treatment and served as controls for both tests. The specimens were randomly polished using PoGo and Sof-Lex systems for 30 seconds after being wet-ground with 1200-grit silicon carbide paper. The mean surface roughness of each polished specimen was determined with a profilometer. The microhardness was determined using a Vickers hardness measuring instrument with a 200-g load and 15 seconds dwell time. The data were analyzed using the Kruskal-Wallis test and the post hoc Dunn's multiple comparison tests at a significance level of .05. Results: Among all materials, the smoothest surfaces were obtained under a matrix strip (control) (P.05). The lowest hardness values for the three resin composites were obtained with a matrix strip, and there was a statistically significant difference compared with other polishing systems (P.05). Conclusion: The current one-step polishing system appears to be as effective as multi-step systems and may be preferable for polishing resin composite restorations. PMID:22509124

  1. Study and comparison of two polishing methods for platinum iridium surfaces, by means of three characterization techniques

    Science.gov (United States)

    Haidar, Y.; Tollens, E.; Silvestri, Z.; de Fornel, F.; Zerrouki, C.; Picard, A.; Pinot, P.

    2005-04-01

    Machining the surface of mass standards is still of great importance. This paper details a comparative study of the roughness of two plane surfaces of a platinum-iridium alloy (90% of platinum and 10% of iridium). Using the BIPM processes, the surfaces were initially machined on a lathe using diamond tools; in addition, one of these was manually polished with a diamond paste. Three techniques for surface characterization are used: shear-force microscopy (ShFM), optical roughness-meter and x-ray reflectometer. The first technique uses the shear-force interaction between the probe and the sample. The ShFM is part of a scanning near-field optical microscope that has the advantage of providing two images simultaneously, a topographical one and a near-field optical one. Only the topographic images will be presented in this paper; the results obtained in optical near-field will be the subject of another publication. To avoid any confusion, we will speak here of ShFM. The topographic images and their associated statistical and physical parameters, such as power spectral densities (PSDs), root-mean-square height, etc, are discussed in this paper. The PSDs of the surface are also determined experimentally from x-ray and visible light scattering measurements using angle-resolved scattering theory. This theory, which is well adapted for visible radiation, is extended to x-rays. The measurements made with the three instruments demonstrate that the two surfaces present a roughness of the same order of magnitude. However, the defects that contribute in a preponderant manner to their roughness spectrum do not belong to the same spatial bandwidth but depend on the polishing process.

  2. The Prediction of Pavement Surface Aggregate Wear and Microtextural Polishing - Progress Report (April 2013)

    OpenAIRE

    NAATADMAJA , Adélia

    2013-01-01

    This report explains the work that the author has done in IFSTTAR, Nantes, France in April 2013. The goals that are aimed to be achieved during her stay are: · Polish and measure the skid resistance values of New Zealand aggregates with the Wehner/Schulze (W/S) device; · Develop a skid resistance deterioration model from the skid resistance values; · Analyse the 3D images of aggregates that are captured by using the InfiniteFocus; · Assess the effects of microtexture evolution on ...

  3. The Prediction of Pavement Surface Aggregate Wear and Microtextural Polishing - Progress Report (March 2013)

    OpenAIRE

    NATAADMADJA, Adelia

    2013-01-01

    This report explains the work that the author has done in IFSTTAR, Nantes, France in March 2013. The goals that are aimed to be achieved during her stay are: · Polish and measure the skid resistance values of New Zealand aggregates with the Wehner/Schulze (W/S) device; · Develop a skid resistance deterioration model from the skid resistance values; · Analyse the 3D images of aggregates that are captured by using the InfiniteFocus; · Assess the effects of microtexture evolution on ...

  4. The prediction of pavement surface aggregate wear and microtextural polishing - Progress report (January-February 2013)

    OpenAIRE

    NATAADMADJA, Adelia

    2013-01-01

    This report explains the work that the author has done in IFSTTAR, Nantes, France from the period of 22 January 2013 to 25 February 2013. The goals that are aimed to be achieved during her stay are: · Polish and measure the skid resistance values of New Zealand aggregates with the Wehner/Schulze (W/S) device; · Develop a skid resistance deterioration model from the skid resistance values; · Analyse the 3D images of aggregates that are captured by using the InfiniteFocus; · Assess ...

  5. Experimental investigation of time and repeated cycles in nucleate pool boiling of alumina/water nanofluid on polished and machined surfaces

    Science.gov (United States)

    Rajabzadeh Dareh, F.; Haghshenasfard, M.; Nasr Esfahany, M.; Salimi Jazi, H.

    2017-12-01

    Pool boiling heat transfer of pure water and nanofluids on a copper block has been studied experimentally. Nanofluids with various concentrations of 0.0025, 0.005 and 0.01 vol.% are employed and two simple surfaces (polished and machined copper surface) are used as the heating surfaces. The results indicated that the critical heat flux (CHF) in boiling of fluids on the polished surface is 7% higher than CHF on the machined surface. In the case of machined surface, the heat transfer coefficient (HTC) of 0.01 vol.% nanofluid is about 37% higher than HTC of base fluid, while in the polished surface the average HTC of 0.01% nanofluid is about 19% lower than HTC of the pure water. The results also showed that the boiling time and boiling cycles on the polished surface changes the heat transfer performance. By increasing the boiling time from 5 to 10 min, the roughness enhances about 150%, but by increasing the boiling time to 15 min, the roughness enhancement is only 8%.

  6. Vanadium and molybdenum oxide thin films on Au(111). Growth and surface characterization

    Energy Technology Data Exchange (ETDEWEB)

    Guimond, Sebastien

    2009-06-04

    The growth and the surface structure of well-ordered V{sub 2}O{sub 3}, V{sub 2}O{sub 5} and MoO{sub 3} thin films have been investigated in this work. These films are seen as model systems for the study of elementary reaction steps occurring on vanadia and molybdena-based selective oxidation catalysts. It is shown that well-ordered V{sub 2}O{sub 3}(0001) thin films can be prepared on Au(111). The films are terminated by vanadyl groups which are not part of the V{sub 2}O{sub 3} bulk structure. Electron irradiation specifically removes the oxygen atoms of the vanadyl groups, resulting in a V-terminated surface. The fraction of removed vanadyl groups is controlled by the electron dose. Such surfaces constitute interesting models to probe the relative role of both the vanadyl groups and the undercoordinated V ions at the surface of vanadia catalysts. The growth of well-ordered V{sub 2}O{sub 5}(001) and MoO{sub 3}(010) thin films containing few point defects is reported here for the first time. These films were grown on Au(111) by oxidation under 50 mbar O{sub 2} in a dedicated high pressure cell. Contrary to some of the results found in the literature, the films are not easily reduced by annealing in UHV. This evidences the contribution of radiation and surface contamination in some of the reported thermal reduction experiments. The growth of ultrathin V{sub 2}O{sub 5} and MoO{sub 3} layers on Au(111) results in formation of interface-specific monolayer structures. These layers are coincidence lattices and they do not correspond to any known oxide bulk structure. They are assumed to be stabilized by electronic interaction with Au(111). Their formation illustrates the polymorphic character and the ease of coordination units rearrangement which are characteristic of both oxides. The formation of a second layer apparently precedes the growth of bulk-like crystallites for both oxides. This observation is at odds with a common assumption that crystals nucleate as soon as a

  7. The effect of carbon impurities on molybdenum surface morphology evolution under high-flux low-energy helium ion irradiation

    International Nuclear Information System (INIS)

    Tripathi, J.K.; Novakowski, T.J.; Gonderman, S.; Bharadwaj, N.; Hassanein, A.

    2016-01-01

    We report on the role of carbon (C) impurities, in molybdenum (Mo) fuzz evolutions on Mo surface during 100 eV He + ion irradiations. In this study we considered 0.01, 0.05, and 0.5% C + ion impurities in He + ion irradiations. For introducing such tiny C + ion impurities, gas mixtures of He and CH 4 have been chosen in following ratios; 99.95: 0.05, 99.75: 0.25, and 97.5: 2.5. Apart from these three cases, two additional cases, 100% He + ion (for Mo fuzz growth due to only He + ions) and 100% H + ion (for confirming the significance of tiny 0.04–2.0% H + ions in terms of Mo fuzz evolutions on Mo surface, if any), have also been considered. Ion energy (100 eV), ion fluence (2.6 × 10 24  ions m −2 ), and target temperature (923 K) were kept constant for each experiment and their selections were based on our previous studies [1,2]. Our study shows homogeneously populated and highly dense Mo fuzz evolutions on entire Mo surface for 100% He + ion irradiation case. Enhancement of C + ion impurities in He + ions causes a sequential reduction in Mo fuzz evolutions, leading to almost complete prevention of Mo fuzz evolutions for 0.5% C + ion impurity concentrations. Additionally, no fuzz formation for 100% H + ion irradiation at all, were seen (apart from some tiny nano-structuring, in very limited regions). This indicates that there is no significant role of H + ions in Mo fuzz evolutions (at least for such tiny amount, 0.04–2.0% H + ions). The study is significant to understand the behavior of potential high-Z plasma facing components (PFCs), in the, presence of tiny amount of C impurities, for nuclear fusion relevant applications. - Highlights: • Mo Fuzz evolutions due to low-energy high-flux 100% He + ion irradiation. • Sequential reduction in Mo fuzz evolutions with increasing C + ion impurities in He + ions. • Almost complete prevention of Mo fuzz evolutions for 0.5% C + ion impurity in He + ions. • No Mo fuzz formation for 100% H + ion

  8. Machining of Molybdenum by EDM-EP and EDC Processes

    Science.gov (United States)

    Wu, K. L.; Chen, H. J.; Lee, H. M.; Lo, J. S.

    2017-12-01

    Molybdenum metal (Mo) can be machined with conventional tools and equipment, however, its refractory propertytends to chip when being machined. In this study, the nonconventional processes of electrical discharge machining (EDM) and electro-polishing (EP) have been conducted to investigate the machining of Mo metal and fabrication of Mo grid. Satisfactory surface quality was obtained using appropriate EDM parameters of Ip ≦ 3A and Ton EDMed Mo metal. Experimental results proved that the appropriate parameters of Ip = 5A and Ton = 50μs at Toff = 10μs can obtain the deposit with about 60μm thickness. The major phase of deposit on machined Mo surface was SiC ceramic, while the minor phases included MoSi2 and/or SiO2 with the presence of free Si due to improper discharging parameters and the use of silicone oil as the dielectric fluid.

  9. Occurrence of molybdenum in British surface water and groundwater: Distributions, controls and implications for water supply

    International Nuclear Information System (INIS)

    Smedley, P.L.; Cooper, D.M.; Ander, E.L.; Milne, C.J.; Lapworth, D.J.

    2014-01-01

    Highlights: • Mo concentrations in British surface water and groundwater are typically low: <2 μg/L. • Urban/industry contamination can increase concentrations above WHO health-based value. • Highest concentrations are consistent with release by oxidation of sulphides. • Highs in mildly reducing groundwaters are consistent with release from metal oxides. • Mo in water is unlikely to pose a major problem for the British water supply industry. - Abstract: Data for Mo in British surface water and groundwater collated from a number of databases show that concentrations are in most cases low, of the order of 2 μg/L or less. However, variability is large and sporadic high values are found in both streamwaters and groundwaters. Data for some 11,600 British streamwater samples indicate a 10–90th percentile range of 0.08–2.44 μg/L with a median of 0.57 μg/L and maximum observation of 230 μg/L. High values tend to be from streams on clay-rich formations and sulphide-mineralised bedrock and streams affected by localised urban and industrial contamination. Monitored lowland river waters also typically have median concentrations <1 μg/L although higher values are present in a number of urban/industrialised English rivers. Highest observed concentrations (median 20 μg/L), occur under low-flow conditions in a river system from an urban, industrial area of NE England and are likely the products of industrial contamination and mine drainage. Concentrations in 96 upland lakewater samples from NW England are universally 0.1 μg/L or less. Data for 1735 groundwater samples from across Britain have a 10–90th percentile range for Mo of 0.035–1.80 μg/L with a median of 0.20 μg/L and maximum observation of 89 μg/L. Relatively high values derive from some Lower Cretaceous greensand, Carboniferous limestone and mudstone (Coal Measures) aquifers, particularly under anaerobic conditions. Release from Fe oxides and possibly Mn oxides by reductive dissolution is a

  10. Design of LD in-band direct-pumping side surface polished micro-rod Nd:YVO4 laser

    International Nuclear Information System (INIS)

    Zhang Wen-Qi; Wang Fei; Liu Qiang; Gong Ma-Li

    2016-01-01

    To diminish the thermal load, two ways, that is, in-band direct pumping and micro-rod crystal, could be adopted at the same time. The efficiency of LD in-band direct-pumping side surface polished micro-rod Nd:YVO 4 laser is numerically analyzed. By optimizing parameters such as crystal length, laser mode radius, pump beam radius, doping concentration and crystal cross-section size, the overall efficiency can reach over 50%. It is found that with micro-rod crystal implemented in the laser oscillator, high overall efficiency LD in-band direct-pumping Nd:YVO 4 laser could be realized. High efficiency combined with low thermal load makes this laser an outstanding scheme for building high-power Nd:YVO 4 lasers. (paper)

  11. Edges in CNC polishing: from mirror-segments towards semiconductors, paper 1: edges on processing the global surface.

    Science.gov (United States)

    Walker, David; Yu, Guoyu; Li, Hongyu; Messelink, Wilhelmus; Evans, Rob; Beaucamp, Anthony

    2012-08-27

    Segment-edges for extremely large telescopes are critical for observations requiring high contrast and SNR, e.g. detecting exo-planets. In parallel, industrial requirements for edge-control are emerging in several applications. This paper reports on a new approach, where edges are controlled throughout polishing of the entire surface of a part, which has been pre-machined to its final external dimensions. The method deploys compliant bonnets delivering influence functions of variable diameter, complemented by small pitch tools sized to accommodate aspheric mis-fit. We describe results on witness hexagons in preparation for full size prototype segments for the European Extremely Large Telescope, and comment on wider applications of the technology.

  12. Method of polishing nickel-base alloys and stainless steels

    Science.gov (United States)

    Steeves, Arthur F.; Buono, Donald P.

    1981-01-01

    A chemical attack polish and polishing procedure for use on metal surfaces such as nickel base alloys and stainless steels. The chemical attack polish comprises Fe(NO.sub.3).sub.3, concentrated CH.sub.3 COOH, concentrated H.sub.2 SO.sub.4 and H.sub.2 O. The polishing procedure includes saturating a polishing cloth with the chemical attack polish and submicron abrasive particles and buffing the metal surface.

  13. R&D progress in SRF surface preparation with centrifugal barrel polishing (cbp) for both Nb and Cu

    Energy Technology Data Exchange (ETDEWEB)

    Palczewski, Ari [JLAB

    2013-09-01

    Centrifugal Barrel polishing (CBP) is becoming a common R&D tool for SRF cavity preparation around the world. During the CBP process a cylindrically symmetric SRF cavity is filled with relatively cheap and environmentally friendly abrasive and sealed. The cavity is then spun around a cylindrically symmetric axis at high speeds uniformly conditioning the inner surface. This uniformity is especially relevant for SRF application because many times a single manufacturing defects limits cavity?s performance well below it?s theoretical limit. In addition CBP has created surfaces with roughness?s on the order of 10?s of nm which create a unique surface for wet chemistry or thin film deposition. CBP is now being utilized at Jefferson Laboratory, Fermi Laboratory and Cornell University in the US, Deutsches Elektronen-Synchrotron in Germany, Laboratori Nazionali di Legnaro in Italy, and Raja Ramanna Centre for Advanced Technology in India. In this talk we will present current CBP research from each lab including equipment, baseline recipes, cavity removal rates and subsequent cryogenic cavity tests on niobium as well as copper cavities where available.

  14. Optical Characterizations of Surface Polished Polycrystalline YAG (Yttrium Aluminum Garnet) Fibers (Postprint)

    Science.gov (United States)

    2017-06-02

    Using a confocal microscope , the rough surface of the polycrystalline YAG fiber was found to be dominant light scattering. To remove surface...the effect of surface roughness on light propagation and scattering coefficient in fibers, and lasing tests of these fibers. Lasing is demonstrated in...based on the mechanical test data, but the loss coefficient could not be lowered further to levels necessary for lasing. Using a confocal microscope

  15. Competition between surface modification and abrasive polishing: a method of controlling the surface atomic structure of 4H-SiC (0001)

    Science.gov (United States)

    Deng, Hui; Endo, Katsuyoshi; Yamamura, Kazuya

    2015-03-01

    The surface atomic step-terrace structure of 4H-SiC greatly affects its performance in power device applications. On the basis of the crystal structure of 4H-SiC, we propose the generation mechanism of the a-b-a*-b* type, a-b type and a-a type step-terrace structures. We demonstrate that the step-terrace structure of SiC can be controlled by adjusting the balance between chemical modification and physical removal in CeO2 slurry polishing. When chemical modification plays the main role in the polishing of SiC, the a-b-a*-b* type step-terrace structure can be generated. When the roles of physical removal and chemical modification have similar importance, the a-b-a*-b* type step-terrace structure changes to the a-b type. When physical removal is dominant, the uniform a-a type step-terrace structure can be generated.

  16. Effect of sodium bicarbonate air abrasive polishing on attrition and surface micromorphology of ceramic and stainless steel brackets.

    Science.gov (United States)

    Parmagnani, Eduardo Augusto; Basting, Roberta Tarkany

    2012-03-01

    To evaluate the frictional resistance of ceramic and metal brackets using rectangular stainless steel orthodontic wires before and after using sodium bicarbonate air abrasive polishing and to evaluate the surface micromorphology of these brackets by means of scanning electron microscopy. Two commercial brands of metal brackets and two commercial brands of ceramic brackets were evaluated. The specimens were divided into eight groups (n  =  10) according to brackets and the application or not of sodium bicarbonate airborne particle abrasion for 10 seconds. A device adapted to a universal testing machine was used to simulate the movement of retraction in sliding mechanics, measuring the traction force needed to slide 10 mm of the wire over the test specimen brackets. The test speed was 5 mm/min. The data were analyzed by two-way analysis of variance (ANOVA) and Tukey test. There was higher frictional resistance after airborne particle abrasion irrespective of the type of bracket (P < .05). One of the ceramic brackets showed higher frictional resistance before and after airborne application than the other metal and ceramic brackets. The micromorphologic analysis showed that airborne particle abrasion caused alterations on the metal bracket surfaces. It may be concluded that it is not recommended to apply airborne particle abrasion on the slots of ceramic or metal brackets.

  17. Validation of in-line surface characterization by light scattering in Robot Assisted Polishing

    DEFF Research Database (Denmark)

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

    2014-01-01

    sensor on the machine in a shop floor environment. Scattered light roughness measurements of the whole surfaces were performed to investigate the measurement method suitability for 100% quality control. For comparison, the surfaces were measured with reference optical instruments in laboratory conditions....... Comparison of the scattered light measurements results taken on the machine with the reference optical roughness measurements taken in laboratory demonstrate the capability of the scattered light sensor for robust in-line surface characterization. This allows for the RAP process control by proper process...

  18. Optical behaviors of esthetic CAD-CAM restorations after different surface finishing and polishing procedures and UV aging: An in vitro study.

    Science.gov (United States)

    Kilinc, Hamiyet; Turgut, Sedanur

    2018-01-05

    Esthetic computer-aided design and computer-aided manufacturing (CAD-CAM) materials have various chemical compositions and can be prepared by using different finishing and polishing procedures. Their optical properties may change over time, depending on these factors. However, information about their stain resistance is still scarce. The purpose of this in vitro study was to evaluate the optical properties of esthetic CAD-CAM materials after different finishing and polishing procedures and ultraviolet (UV) aging. Lava Ultimate, Cerasmart, Vita Enamic, Vita Suprinity, and Vita Mark II materials were used. A total of 150 specimens (14×12×1 mm) were prepared (n=10). A spectrophotometer was used to measure color parameters after different finishing and polishing procedures (control, manual polishing, glazing) and ultraviolet (UV) aging. Lightness (L*), green-red (a*), blue-yellow (b*), chroma (Ch), and hue (h) parameters were recorded, and change in lightness (ΔE*) values were calculated. Statistical analyses were performed with 2-way ANOVA, the Fisher least significant difference test, and the paired samples t test (α=.05). Significant interactions were noted between the aging conditions, material type, and finishing and polishing procedures for all evaluated parameters (P<.001). Vita Suprinity and Vita Mark II glazing groups resulted in significantly higher L 1 * values (P<.05) after the first color measurements. The b 1 * and C 1 values of Vita Suprinity were higher than for other materials (P<.05). The highest ΔE* value was observed in the Lava Ultimate-glazing group (ΔE*=22.7) and the lowest in the Vita Mark II-control group (ΔE*=0.86). The optical properties of CAD-CAM materials can be affected by the material type and the applied surface finishing and polishing procedure. Manual polishing seems to be a better choice for Lava Ultimate and Cerasmart and glazing for Vita Enamic. For ceramic materials, manual polishing or glazing can be recommended in terms

  19. Comparative analysis on surface property in anodic oxidation polishing of reaction-sintered silicon carbide and single-crystal 4H silicon carbide

    Science.gov (United States)

    Shen, Xinmin; Tu, Qunzhang; Deng, Hui; Jiang, Guoliang; He, Xiaohui; Liu, Bin; Yamamura, Kazuya

    2016-04-01

    For effective machining of difficult-to-machine materials, such as reaction-sintered silicon carbide (RS-SiC) and single-crystal 4H silicon carbide (4H-SiC), a novel polishing technique named anodic oxidation polishing was proposed, which combined with the anodic oxidation of substrate and slurry polishing of oxide. By scanning electron microscopy/energy-dispersive X-ray spectroscopy (SEM-EDX) observation and atomic force microscopy analysis, both the anodic oxidation behaviors of RS-SiC and 4H-SiC were investigated. Through comparison of the surfaces before and after hydrofluoric acid etching of the oxidized samples by the scanning white light interferometry (SWLI) measurement, the relationships between oxidation depth and oxidation time were obtained, and the calculated oxidation rate for RS-SiC was 5.3 nm/s and that for 4H-SiC was 5.8 nm/s based on the linear Deal-Grove model. Through anodic oxidation polishing of RS-SiC substrate and 4H-SiC substrate, respectively, the surface roughness rms obtained by SWLI was improved to 2.103 nm for RS-SiC and to 0.892 nm for 4H-SiC. Experimental results indicate that anodic oxidation polishing is an effective method for the machining of RS-SiC and 4H-SiC samples, which would improve the process level of SiC substrates and promote the application of SiC products in the fields of optics, ceramics, semiconductors, electronics, and so on.

  20. SURFACE CHARACTERIZATION OF NIOBIUM SAMPLES ELECTRO-POLISHED TOGETHER WITH REAL CAVITIES

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Xin [William and Mary College; Geng, Rongli [JLAB; Funahashi, Y. [KEK; Hayano, H. [KEK; Kato, S. [KEK; Nishiwaki, M. [KEK; Saeki, T. [KEK; Sawabe, M. [KEK; Ueno, K. [KEK; Watanabe, K. [KEK; Tyagi, P. V. [GUAS/AS, Ibaraki

    2009-11-01

    We report the results of surface characterizations of niobium samples electropolished together with single cell cavities. These witness samples were located in three regions of the cavity, namely at the equator, the iris and the beam-pipe. Auger electron spectroscopy (AES) was utilized to probe the chemical composition of the topmost four atomic layers. Scanning electron microscopy with energy dispersive x-ray for elemental analysis (SEM/EDX) was used to observe the surface topography and chemical composition at the micrometer scale. A few atomic layers of sulphur (S) were found covering the samples non-uniformly. Niobium oxide granules with a sharp geometry were observed on every sample. Some Nb-O granules appeared to also contain sulphur.

  1. Polish visit

    CERN Document Server

    2003-01-01

    On 6 October, Professor Michal Kleiber, Polish Minister of Science and Chairman of the State Committee for Scientific Research, visited CERN and met both the current and designated Director General, Luciano Maiani and Robert Aymar. Professor Kleiber visited the CMS and ATLAS detector assembly halls, the underground cavern for ATLAS, and the LHC superconducting magnet string test hall. Michal Kleiber (left), Polish minister of science and Jan Krolikowski, scientist at Warsaw University and working for CMS, who shows the prototypes of the Muon Trigger board of CMS.

  2. Attack polish for nickel-base alloys and stainless steels

    Science.gov (United States)

    Not Available

    1980-05-28

    A chemical attack polish and polishing procedure for use on metal surfaces such as nickel base alloys and stainless steels is described. The chemical attack polich comprises FeNO/sub 3/, concentrated CH/sub 3/COOH, concentrated H/sub 2/SO/sub 4/ and H/sub 2/O. The polishing procedure includes saturating a polishing cloth with the chemical attack polish and submicron abrasive particles and buffing the metal surface.

  3. The role of molybdenum in the dissolution and passivation of nickel-molybdenum alloys. Influence of sulphur

    International Nuclear Information System (INIS)

    Moscatelli, Michel

    1987-01-01

    This research thesis addresses the sulphur-molybdenum interactions during dissolution and passivation processes of mono-crystalline nickel-molybdenum alloys. It more particularly addresses the influence of molybdenum and sulphur on the electrochemical behaviour of nickel-base alloys. With the use of radiochemical and electrochemical techniques, it shows the destabilizing effect of molybdenum on the adsorbed sulphur. In the case of doped alloys, increased contents of molybdenum slow down the sulphur surface enrichment, and result in a passive film which can form in conditions under which, in absence of molybdenum, passivation would be stopped by sulphur. Molybdenum therefore increases corrosion resistance of alloys in presence of sulphur. The application of the P. Marcus's theoretical model allows the understanding of the destabilizing effect of molybdenum on sulphur. In absence of sulphur and in the cathodic range, molybdenum accelerates recombination with hydrogen: this could be interesting with respect to hydrogen embrittlement. Sulphur slows down hydrogen release kinetics, but is partially desorbed in presence of molybdenum. Passive films formed on alloy surfaces are studied by RBS, AES and ESCA [fr

  4. Molybdenum nutriture in humans

    Science.gov (United States)

    Molybdenum is a trace element that functions as a cofactor for at least four enzymes: sulfite oxidase, xanthine oxidase, aldehyde oxidase, and mitochondrial amidoxime reducing component. In each case, molybdenum is bound to a complex, multi-ring organic component called molybdopterin, forming the e...

  5. Molybdenum market in transition

    International Nuclear Information System (INIS)

    Sutulov, A.

    1980-01-01

    Since the beginning of 1980 - after seven years of constant unbalance between supply and demand of molybdenum, characterized by a demand overhang and after two years of unprecedented spot market prices - clear signals for a consolidation of the molybdenum market can be recognized. (orig.) [de

  6. Structure, activity and kinetics of supported molybdenum oxide and mixed molybdenum-vanadium oxide catalysts prepared by flame spray pyrolysis for propane OHD

    DEFF Research Database (Denmark)

    Høj, Martin; Kessler, Thomas; Beato, Pablo

    2013-01-01

    reflectance UV-vis spectroscopy and evaluated as catalysts for the oxidative dehydrogenation (ODH) of propane. The results show that samples with high specific surface areas between 122 and 182 m2/g were obtained, resulting in apparent MoOx and VOx surface densities from 0.7 to 7.7 nm -2 and 1.5 to 1.9 nm-2......, respectively. Raman spectroscopy, UV-vis spectroscopy and XRD confirmed the high dispersion of molybdenum and vanadia species on γ-Al2O3 as the main crystalline phase. Only at the highest loading of 15 wt% Mo, with theoretically more than monolayer coverage, some crystalline molybdenum oxide was observed....... For the mixed molybdenum-vanadium oxide catalysts the surface species were separate molybdenum oxide and vanadium oxide monomers at low loadings of molybdenum, but with increasing molybdenum loading interactions between surface molybdenum and vanadium oxide species were observed with Raman spectroscopy...

  7. The need for verification of the Polish lignite deposits owing to development and nature conservation protection on land at the surface

    Directory of Open Access Journals (Sweden)

    Naworyta Wojciech

    2016-12-01

    Full Text Available Poland is a country rich in lignite. The area where the lignite occurs occupies approx. 22% of the total surface area of the country. Geological resources of Polish lignite deposits are estimated at 23.5 billion Mg, but in the majority (69% the accuracy of their identification is poor. Nevertheless the amount of coal in Polish deposits allows - at least in theory - for mining and energy production at the current level for hundreds of years to come. It is an important raw material for the energy security of the country both currently and in the future. Because the vast majority of Polish and foreign mines use an open pit method for lignite extraction the actual amount of mineral available for the extraction depends not only on the properties of the deposit but to a large extent on the method of development of the surface land above the deposit, as well as on the sensitivity of the environment in the vicinity of any future mines. After careful analysis it can be stated that only a few of the lignite deposits may be subject to cost-effective mining operations. These deposits should be subjected to special protection as a future resource base which will ensure the energy security of the country. Some examples of domestic deposits have been presented where due to the conflict resulting from the development of the area should be deleted from the Balance Sheet of Mineral Deposits because their exploitation is irrational and uneconomic. Keeping such deposits in the Balance Sheet, and the use of large numbers in the context of their resource base leads to an unwarranted sense of wealth which consequently does not encourage the protection of these deposits which may actually be subject to rational exploitation in the near future. In summary there is a need to find a compromise in order to adequately protect all natural resources including mineral deposits.

  8. Electronic states on the clean and oxygen-covered molybdenum (110) surface measured using time-of-flight momentum microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Chernov, Sergii

    2016-04-20

    Recent experiments discovered a new class of materials called topological insulators and started an extensive investigation in order to find more materials of such type and to understand and explore the opening perspectives in fundamental science and application. These materials exhibit a Dirac-type (massless) electronic state, bridging the fundamental band gap. Surprisingly, a strongly spin-polarized surface state with linear dispersion resembling that of Dirac type was found on the already well-investigated W(110) surface. This rose the question of the existence of the same non-trivial electron state on other metal surfaces. The present work describes the investigation of surface electronic states on the Mo(110) surface, their dispersion and transformation upon surface oxidation. This system is isoelectronic to the case of W(110) but due to the lower atomic number the spin-orbit interaction responsible for local band gap formation is substantially decreased by a factor of 5. The Mo(110) surface was shown to exhibit a linearly dispersing state quite similar to the one on W(110), but within a smaller energy range of 120 meV, with the Dirac point lying in the center of a local band gap in k-space. The experimental investigations were performed with the help of momentum microscopy, using a Ti:sapphire laser in the lab and synchrotron radiation at BESSY II, Berlin. The results show good agreement with theoretical calculations of the band structure and photoemission patterns for clean Mo(110). The fully parallel 3D acquisition scheme allowed to visualize the full surface Brillouin zone of the sample up to few eV binding energy within a single exposure of typically less than 30 min. This opens the door to future time-resolved experiments with maximum detection efficiency.

  9. Evaluation of the surface roughness of three heat-cured acrylic denture base resins with different conventional lathe polishing techniques: A comparative study

    Directory of Open Access Journals (Sweden)

    Duggineni Chalapathi Rao

    2015-01-01

    Results: Among the materials tested, better results were obtained with Trevalon Hi followed by Meliodent and DPI. Among the polishing methods used, superior results were obtained with universal polishing paste followed by polishing cake; Pumice and Gold rouge. Although Pumice and Gold rouge values produced greater roughness value, they were well within the threshold value of 0.2 mm.

  10. Effects of focused ion beam milling on the compressive behavior of directionally solidified micro-pillars and the nanoindentation response of an electro-polished surface

    International Nuclear Information System (INIS)

    Shim, Sang Hoon; Bei, Hongbin; Miller, Michael K; Pharr, George Mathews; George, Easo P

    2009-01-01

    Focused ion beam (FIB) milling is the typical way in which micro-pillars are fabricated to study small-scale plasticity and size effects in uniaxial compression. However, FIB milling can introduce defects into the milled pillars. To investigate the effects of FIB damage on mechanical behavior, we tested Mo-alloy micro-pillars that were FIB milled following directional solidification, and compared their compressive response to pillars that were not FIB milled. We also FIB milled at glancing incidence a Mo-alloy single-crystal surface, and compared its nanoindentation response to an electro-polished surface of the same crystal. Consequences for the interpretation of data obtained from FIB milled micro-pillars are discussed

  11. Effects of electrical discharge surface modification of superalloy Haynes 230 with aluminum and molybdenum on oxidation behavior

    International Nuclear Information System (INIS)

    Bai, C.-Y.

    2007-01-01

    The effects of the electrical discharge alloying (EDA) process on improving the high temperature oxidation resistance of the Ni-based superalloy Haynes 230 have been investigated. The 85 at.% Al and 15 at.% Mo composite electrode provided the surface alloying materials. An Al-rich layer is produced on the surface of the EDA specimen alloyed with positive electrode polarity, whereas, many discontinuous piled layers are attached to the surface of the EDA superalloy when negative electrode polarity is selected. The oxidation resistance of the specimen alloyed with positive electrode polarity is better than that of the unalloyed superalloy, and the effective temperature of oxidation resistance of the alloyed layer can be achieved to 1100 o C. Conversely, the oxidation resistance of the other EDA specimen alloyed with negative electrode polarity is even worse than that of the unalloyed superalloy

  12. Advanced techniques for computer-controlled polishing

    Science.gov (United States)

    Schinhaerl, Markus; Stamp, Richard; Pitschke, Elmar; Rascher, Rolf; Smith, Lyndon; Smith, Gordon; Geiss, Andreas; Sperber, Peter

    2008-08-01

    Computer-controlled polishing has introduced determinism into the finishing of high-quality surfaces, for example those used as optical interfaces. Computer-controlled polishing may overcome many of the disadvantages of traditional polishing techniques. The polishing procedure is computed in terms of the surface error-profile and the material removal characteristic of the polishing tool, the influence function. Determinism and predictability not only enable more economical manufacture but also facilitate considerably increased processing accuracy. However, there are several disadvantages that serve to limit the capabilities of computer-controlled polishing, many of these are considered to be issues associated with determination of the influence function. Magnetorheological finishing has been investigated and various new techniques and approaches that dramatically enhance the potential as well as the economics of computer-controlled polishing have been developed and verified experimentally. Recent developments and advancements in computer-controlled polishing are discussed. The generic results of this research may be used in a wide variety of alternative applications in which controlled material removal is employed to achieve a desired surface specification, ranging from surface treatment processes in technical disciplines, to manipulation of biological surface textures in medical technologies.

  13. Process for purifying molybdenum

    International Nuclear Information System (INIS)

    Cheresnowsky, J.

    1989-01-01

    This patent describes a process for purifying molybdenum containing arsenic and phosphorus. The process comprising: adding to an acidic slurry of molybdenum trioxide, a source of magnesium ions in a solid form, with the amount of magnesium and the magnesium ion concentration in the subsequently formed ammonium molybdate solution being sufficient to subsequently form insoluble compounds containing greater than about 80% by weight of the arsenic and greater than about 80% by weight of the phosphorus, and ammonia in an amount sufficient to subsequently dissolve the molybdenum and subsequently form the insoluble compounds, with the source of magnesium ions being added prior to the addition of the ammonia; digesting the resulting ammoniated slurry at a temperature sufficient to dissolve the molybdenum and form an ammonium molybdate solution while the pH is maintained at from bout 9 to about 10 to form a solid containing the insoluble compounds; and separating the solid from the ammonium molybdate solution

  14. Organometallic Chemistry of Molybdenum.

    Science.gov (United States)

    Lucas, C. Robert; Walsh, Kelly A.

    1987-01-01

    Suggests ways to avoid some of the problems students have learning the principles of organometallic chemistry. Provides a description of an experiment used in a third-year college chemistry laboratory on molybdenum. (TW)

  15. APS 3D: a new benchmark in aspherical polishing

    Science.gov (United States)

    Gauch, Daniel; Mikulic, Dalibor; Veit, Christian

    2017-10-01

    The APS 3D system performs polishing and form correction in one step in order to reduce overall process time, reduce the number of polishing steps required and eliminate the need for highly skilled operators while providing a repeatable polishing process. This new 3D Polishing system yields better surface quality, and a better slope error, automatically determining the optimum speeds, feed rates and polish pressures to achieve a deterministic process based on the required quality parameters input by the operator. The process flow is always the same to ensure consistent quality and target quality values are defined before polishing begins.

  16. Pathway and Surface Mechanism Studies of 1,3-butadiene Selective Oxidation Over Vanadium-Molybdenum-Oxygen Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Schroeder, William David [Iowa State Univ., Ames, IA (United States)

    2001-01-01

    The partial oxidation of 1,3-butadiene has been investigated over VMoO catalysts synthesized by sol-gel techniques. Surface areas were 9-14 m2/g, and compositions were within the solid solution regime, i.e. below 15.0 mol % MoO3/(MoO3 + V2O5). Laser Raman Spectroscopy and XRD data indicated that solid solutions were formed, and pre- and post-reaction XPS data indicated that catalyst surfaces contained some V+4 and were further reduced in 1,3-butadiene oxidation. A reaction pathway for 1,3-butadiene partial oxidation to maleic anhydride was shown to involve intermediates such as 3,4-epoxy-1-butene, crotonaldehyde, furan, and 2-butene-1,4-dial. The addition of water to the reaction stream substantially increased catalyst activity and improved selectivity to crotonaldehyde and furan at specific reaction temperatures. At higher water addition concentrations, furan selectivity increased from 12% to over 25%. The catalytic effects of water addition were related to competitive adsorption with various V2O5-based surface sites, including the vanadyl V=O, corner sharing V-O-V and edge sharing V-O oxygen. Higher levels of water addition were proposed to impose acidic character by dissociative adsorption. In addition, a novel combinatorial synthesis technique for VMoO was used to investigate the phase transitions of V2O5, solid solutions of Mo in V2O5, V9Mo6O40, and other reduced VMoO compounds, characterized by laser Raman spectroscopy. The natural composition gradient imposed by the sputter deposition apparatus was used to create VMoO arrays containing 225 samples ranging from 7.0-42 mol% MoO3/(V2O5 + MoO3), determined by EDS analysis.

  17. Super-polishing of Zerodur aspheres by means of conventional polishing technology

    Science.gov (United States)

    Polak, Jaroslav; Klepetková, Eva; Pošmourný, Josef; Šulc, Miroslav; Procháska, František; Tomka, David; Matoušek, Ondřej; Poláková, Ivana; Šubert, Eduard

    2015-01-01

    This paper describes a quest to find simple technique to superpolish Zerodur asphere (55μm departure from best fit sphere) that could be employed on old fashion way 1-excenter optical polishing machine. The work focuses on selection of polishing technology, study of different polishing slurries and optimization of polishing setup. It is demonstrated that either by use of fine colloidal CeO2 slurry or by use of bowl-feed polishing setup with CeO2 charged pitch we could reach 0.4nm RMS roughness while removing <30nm of surface layer. This technique, although not optimized, was successfully used to improve surface roughness on already prepolished Zerodur aspheres without necessity to involve sophisticated super-polishing technology and highly trained manpower.

  18. Monitoring of Robot Assisted Polishing through parameters of acoustic emission

    DEFF Research Database (Denmark)

    Lazarev, Ruslan; Top, Søren; Bilberg, Arne

    The polishing process is essential for the surface generation of machine tooling components in advanced manufacturing. While robot assisted polishing is faster and more consistent than manual polishing, it can still consume a significant part of ma- chining time and operator presence time...

  19. Material removal mechanisms in abrasive vibration polishing of complex molds

    Science.gov (United States)

    Brinksmeier, E.; Riemer, O.; Schulte, H.

    2010-10-01

    Optical and medical industries are demanding a large variety of optical elements exhibiting complex geometries and multitude opto-functional areas in the range of a few millimeters [1]. Therefore, mold inserts made of steel or carbides must be finished by polishing for the replication of glass and plastic lenses [2]. For polishing theses complex components in the shape of localized cavities or grooves the application of rotating polishing pads is very limited. Established polishing processes are not applicable, so state of the art is a time consuming and therefore expensive polishing procedures by hand. An automated process with conventional polishing machines is impossible because of the complex mold insert geometry. The authors will present the development of a new abrasive polishing process for finishing these complex mold geometries to optical quality. The necessary relative velocity in the contact area between polishing pad and workpiece surface is exclusively realized by vibration motions which is an advantage over vibration assisted rotating polishing processes. The absence of rotation of the pad opens up the possibility to machine new types of surface geometries. The specific influence factors of vibration polishing were analyzed and will be presented. The determination of material removal behavior and polishing effect on planar steel samples has shown that the conventional abrasive polishing hypothesis of Preston is applicable to the novel vibration polishing process. No overlaid chemical material removal appears.

  20. A study on the relationships between corrosion properties and chemistry of thermally oxidised surface films formed on polished commercial magnesium alloys AZ31 and AZ61

    Energy Technology Data Exchange (ETDEWEB)

    Feliu, Sebastián, E-mail: sfeliu@cenim.csic.es [Centro Nacional de Investigaciones Metalúrgicas CSIC, Avda. Gregorio del Amo 8, 28040 Madrid (Spain); Samaniego, Alejandro [Centro Nacional de Investigaciones Metalúrgicas CSIC, Avda. Gregorio del Amo 8, 28040 Madrid (Spain); Barranco, Violeta [Instituto de Ciencias de Materiales de Madrid, ICMM, Consejo Superior de Investigaciones Científicas, CSIC, Sor Juana Inés de la Cruz, 3, Cantoblanco, 28049, Madrid (Spain); El-Hadad, A.A. [Physics Department, Faculty of Science, Al-Azhar University, Nasr City 11884, Cairo (Egypt); Llorente, Irene [Centro Nacional de Investigaciones Metalúrgicas CSIC, Avda. Gregorio del Amo 8, 28040 Madrid (Spain); Serra, Carmen [Servicio de Nanotecnologia y Análisis de Superficies, CACTI, Universidade de Vigo, 36310 Vigo (Spain); Galván, J.C. [Centro Nacional de Investigaciones Metalúrgicas CSIC, Avda. Gregorio del Amo 8, 28040 Madrid (Spain)

    2014-03-01

    Highlights: • Surface chemistry of heat treated magnesium alloys. • Relation between heat treatment and aluminium subsurface enrichment. • Relation between surface composition and corrosion behaviour. - Abstract: This paper studies the changes in chemical composition of the thin oxide surface films induced by heating in air at 200 °C for time intervals from 5 min to 60 min on the freshly polished commercial AZ31 and AZ61 alloys with a view to better understanding their protective properties. This thermal treatment resulted in the formation of layers enriched in metallic aluminium at the interface between the outer MgO surface films and the bulk material. A strong link was found between the degree of metallic Al enrichment in the subsurface layer (from 10 to 15 at.%) observed by XPS (X-ray photoelectron spectroscopy) in the AZ61 treated samples and the increase in protective properties observed by EIS (electrochemical impedance spectroscopy) in the immersion test in 0.6 M NaCl. Heating for 5–60 min in air at 200 °C seems to be an effective, easy to perform and inexpensive method for increasing the corrosion resistance of the AZ61 alloy by approximately two or three times.

  1. Sensing roughness and polish direction

    DEFF Research Database (Denmark)

    Jakobsen, Michael Linde; Olesen, Anders Sig; Larsen, Henning Engelbrecht

    2016-01-01

    needs information about the RMS-value of the surface roughness and the current direction of the scratches introduced by the polishing process. The RMS-value indicates to the operator how far he is from the final finish, and the scratch orientation is often specified by the customer in order to avoid...... structures and light scattered from scratches....

  2. Bibliographic study on molybdenum biokinetics

    International Nuclear Information System (INIS)

    Erzberger, A.

    1988-05-01

    This bibliographical study compiles and analyzes findings about the metabolism and resorption of molybdenum. Besides including studies on the physiology of molybdenum 99, a general survey is given on molybdenum in the environment and on its physiological behaviour. In particular, information on the dependence of molybdenum resorption on various factors, such as the chemical form, antagonisms etc., are gathered from literature. These factors have to be considered for sensibly carrying out necessary experiments. (orig./MG) [de

  3. Efficient polishing of aspheric optics

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, J.S.; Piscotty, M.A.; Nguyen, N.Q.; Landram, C.S.; Ng, L.C.

    1997-04-15

    The objectives of this project are to develop, evaluate, and optimize novel designs for a polishing tool intended for ultra-precise figure corrections on aspheric optics with tolerances typical of those required for use in extreme ultraviolet (EUV) projection lithography. This work may lead to an enhanced US industrial capability for producing optics for EUV, x-ray and, other high precision applications. LLNL benefits from developments in computer-controlled polishing and the insertion of fluid mechanics modeling into the precision manufacturing area. Our accomplishments include the numerical estimation of the hydrodynamic shear stress distribution for a new polishing tool that directs and controls the interaction of an abrasive slurry with an optical surface. A key milestone is in establishing a correlation between the shear stress predicted using our fluid mechanics model and the observed removal footprint created by a prototype tool. In addition, we demonstrate the ability to remove 25 nm layers of optical glass in a manner qualitatively similar to macroscopic milling operations using a numerically- controlled machine tool. Other accomplishments include the development of computer control software for directing the polishing tool and the construction of a polishing testbed.

  4. Electrodeposition of tungsten coatings on molybdenum substrates and deuterium irradiation effect

    International Nuclear Information System (INIS)

    Lian, Ziwei; Fang, Xianqin; Han, Wenjia; Yu, Jiangang; Wang, Zhanlei; Zhang, Ying; Zhu, Kaigui

    2016-01-01

    Highlights: • Tungsten coatings were successfully electroplated on molybdenum substrates. • The current density affected the performance of tungsten coatings. • Deuterium irradiation property of tungsten coatings was investigated. • Deuterium retention in the tungsten coating was less than that in the bulk tungsten. - Abstract: Tungsten coatings were prepared using pulse electrodeposition on the molybdenum substrates. Effects of variations in current density on surface morphology, thickness distribution and crystal orientation of the coatings were investigated. The results indicate that with the current density increasing, the grain size of tungsten coatings first decreases, then increases; while the deposited thickness increases all the time. And all of tungsten coatings exhibit the preferred orientation of (200) plane. Moreover, the polished tungsten coating and bulk tungsten were exposed to low energy (80 eV) and high flux (7.2 × 10 20 D/m 2 /s) deuterium plasma in a linear plasma device (Simulator of Tokamak Edge Plasma, STEP). Deuterium (D) retention was measured by thermal desorption spectroscopy (TDS). It is found that blisters on the tungsten coating are much fewer than that on the bulk tungsten. TDS spectroscopy of the tungsten coating reveals one D 2 release peak at 740 K, while the bulk tungsten has two D 2 release peaks at 500 K and 660 K. The amount of deuterium retention in the tungsten coating is lower.

  5. Metal polish poisoning

    Science.gov (United States)

    Metal polishes are used to clean metals, including brass, copper, or silver. This article discusses the harmful effects from swallowing metal polish. This article is for information only. DO NOT use ...

  6. Williamson Polishing & Plating Site

    Science.gov (United States)

    Williamson Polishing & Plating Co. Inc. was a plating shop located in the Martindale-Brightwood neighborhood of Indianapolis. The facility conducted job shop polishing and electroplating services. The vacant site contains a 14,651-square-foot building.

  7. Molybdenum solar neutrino experiment

    International Nuclear Information System (INIS)

    Wolfsberg, K.; Cowan, G.A.; Bryant, E.A.

    1984-01-01

    The goal of the molybdenum solar neutrino experiment is to deduce the 8 B solar neutrino flux, averaged over the past several million years, from the concentration of 98 Tc in a deeply buried molybdenum deposit. The experiment is important to an understanding of stellar processes because it will shed light on the reason for the discrepancy between theory and observation of the chlorine solar neutrino experiment. Possible reasons for the discrepancy may lie in the properties of neutrinos (neutrino oscillations or massive neutrinos) or in deficiencies of the standard solar model. The chlorine experiment only measures the 8 B neutrino flux in current times and does not address possible temporal variations in the interior of the sun, which are also not considered in the standard model. In the molybdenum experiment, we plan to measure 98 Tc (4.2 Myr), also produced by 8 B neutrinos, and possibly 97 Tc (2.6 Myr), produced by lower energy neutrinos

  8. Method of producing molybdenum-99

    Science.gov (United States)

    Pitcher, Eric John

    2013-05-28

    Method of producing molybdenum-99, comprising accelerating ions by means of an accelerator; directing the ions onto a metal target so as to generate neutrons having an energy of greater than 10 MeV; directing the neutrons through a converter material comprising techentium-99 to produce a mixture comprising molybdenum-99; and, chemically extracting the molybdenum-99 from the mixture.

  9. QCM and AFM Study of atomic scale polishing and roughening of surfaces exposed to nanoparticle suspensions of diamond, Al2O3 and SiO2.

    Science.gov (United States)

    Krim, Jacqueline; Acharya, Biplav; Chestnut, Melanie; Marek, Antonin; Shendarova, Olga; Smirnov, Alex

    The addition of nanoparticles to conventional automotive lubricants is known in many cases to result in increased energy efficiency, but the atomic scale mechanisms leading to the increased efficiency are yet to be established. To explore this issue, we studied surface uptake and nanotribological properties of nanoparticle suspensions of diamond, Al2O3 and SiO2 dispersed in water and/or oil (PAO6) in real time by means of an in situ Quartz Crystal Microbalance (QCM) technique, with a focus on the impact of the suspension on the surface roughness and texture of the QCM electrode and how the results compared to macroscopic reductions in friction and increased energy efficiency for the same materials' combinations. The frequency and dissipative properties (mechanical resistance) of QCM's with both gold and nickel surface electrodes were first studied for immersed samples upon addition of the nanoparticles. Nanodiamonds resulted in an increased mechanical resistance while the addition of Al2O3 and SiO2 nanoparticles resulted in a decreased resistance, indicating a reduced resistance of the fluid to the motion of the QCM. Atomic Force Microscope (AFM) measurements were then performed on the QCM electrodes after exposure to the suspensions, to explore potential polishing and/or roughening effects. The results are closely linked to the macroscopic friction and wear attributes. Work supported by NSF.

  10. Effect of Pad Surface Roughness on SiO2 Removal Rate in Chemical Mechanical Polishing with Ceria Slurry

    Science.gov (United States)

    Yoshida, Masato; Ono, Hiroshi; Nishiyama, Masaya; Ashizawa, Toranosuke; Doi, Toshiro

    2006-02-01

    The effect of pad surface roughness on SiO2 removal rate was investigated using four different slurries containing ceria (CeO2) powders of different crystallite sizes and mean particle sizes. A clear maximum was observed in the dependence of removal rate on pad surface roughness. The four ceria slurries showed a peak in blanket wafer removal rate against pad surface roughness Ra. The peak moved toward larger Ra values with decreasing ceria crystallite size. The removal rate was strongly influenced not only by pad surface roughness but also by the crystallite size of ceria in the slurry.

  11. Laser polishing of additive manufactured Ti alloys

    Science.gov (United States)

    Ma, C. P.; Guan, Y. C.; Zhou, W.

    2017-06-01

    Laser-based additive manufacturing has attracted much attention as a promising 3D printing method for metallic components in recent years. However, surface roughness of additive manufactured components has been considered as a challenge to achieve high performance. In this work, we demonstrate the capability of fiber laser in polishing rough surface of additive manufactured Ti-based alloys as Ti-6Al-4V and TC11. Both as-received surface and laser-polished surfaces as well as cross-section subsurfaces were analyzed carefully by White-Light Interference, Confocal Microscope, Focus Ion Beam, Scanning Electron Microscopy, Energy Dispersive Spectrometer, and X-ray Diffraction. Results revealed that as-received Ti-based alloys with surface roughness more than 5 μm could be reduce to less than 1 μm through laser polishing process. Moreover, microstructure, microhardness and wear resistance of laser-polished zone was investigated in order to examine the thermal effect of laser polishing processing on the substrate of additive manufactured Ti alloys. This proof-of-concept process has the potential to effectively improve the surface roughness of additive manufactured metallic alloy by local polishing method without damage to the substrate.

  12. STUDY OF POLISHING AISI 316L WITH STRUCTURED ABRASIVE

    Directory of Open Access Journals (Sweden)

    François GOOSSENS

    2015-05-01

    Full Text Available Finishing process like polishing is usually used to obtain high quality mechanical surface characteristics such as texture and roughness. These operations are mainly handmade and need highly trained operators thus limiting their repeatability and profitability. To optimize the industrialization of the polishing process, it is therefore necessary to modelize the process to built efficient parameter database. The aim of this study is to characterise the polishing of 316L stainless steel with structured abrasive belts. The geometric data of the belts are given, and we then propose a model to determine material removal. An experimental test bench is set up to test this model and characterise the polishing process in terms of forces. It produces samples for different polishing conditions. The different polished surfaces are then analyzed thanks to the roughness and the wettability. Using experimental designs, we are able to validate the proposed model and identify the parameters that influence a polishing operation.

  13. Characterization and Streptococcus mutans adhesion on air polishing dentin.

    Science.gov (United States)

    Tada, Kazuhiro; Oda, Hirotake; Inatomi, Michitomo; Sato, Soh

    2014-07-01

    Air polishing is known as an effective and time saving tooth cleaning method. However, this method increased surface roughness and bacterial adhesion on dentin surface. The aim of this study was to characterize and examine Streptococcus mutans adhesion on dentin surface after air polishing as compared to the conventional method. The dentin blocks (4 × 4 × 1 mm) were polished by a rubber cup with polishing material (Polishing) and air-polished by 25 μm glycine (G25), 65 μm glycine (G65), and 65 μm sodium bicarbonate (NHC65) microparticles. Surface roughness (Ra) was measured by a laser electron microscope. The amount of adhered S. mutans was quantified using a resazurin reduction assay (alamarBlue(®)). The Ra of G25 and G65 was significantly (p < 0.01) smaller than that of NHC65 and greater than that of Polishing. However, there was no significant difference in S. mutans adhesion among Polishing, G25, and G65, while NHC65 showed significantly (p < 0.01) higher S. mutans adhesion. Within the limitations of this in vitro study, air polishing using glycine microparticles conditioned S. mutans adhesion on dentin surface in a similar fashion than the conventional method, and less than air polishing using sodium bicarbonate microparticles.

  14. Chemistry and uses of molybdenum

    International Nuclear Information System (INIS)

    Fifty-six papers were presented at the Climax Third International Conference on the Chemistry and Uses of Molybdenum. The tremendous importance of the use of molybdenum compounds in industrial catalytic applications is highlighted in these proceedings. The structure and resultant catalytic activity of molybdates and oxides is detailed for the varied reactions of hydrodesulfurization, selective oxidation and oxidative dehydrogenation. The future role that molybdenum compounds will play in coal liquefaction is also stressed; molybdenum catalysts appear to be an essential ingredient in the US energy self-sufficiency program. New insights into fundamental molybdenum chemistry are provided by research directed towards the electronic structure and the thermochemical strength of molybdenum-molybdenum bonds. The synthesis of new organo-molybdenum compounds and the chemistry of Mo-Mo triple bonds in cyclic compounds is described. Model studies of molybdenum enzymes help to illuminate the structure and spectroscopic properties of these compounds. Studies of the molybdenum centers in xanthine oxidase, sulfite oxidase and nitrate reductase are reviewed. Fifteen papers are abstracted separately

  15. Storage and Bioavailability of Molybdenum in Soils Increased by Organic Matter Complexation

    Energy Technology Data Exchange (ETDEWEB)

    Wichard, T.; Mishra, B; Myneni, S; Bellenger, J; Kraepiel, A

    2009-01-01

    The micronutrient molybdenum is a necessary component of the nitrogen-fixing enzyme nitrogenase1, 2. Molybdenum is very rare in soils, and is usually present in a highly soluble form, making it susceptible to leaching3, 4. However, it is generally thought that molybdenum attaches to mineral surfaces in acidic soils; this would prevent its escape into the groundwater, but would also impede uptake by microbes3. Here we use X-ray spectroscopy to examine the chemical speciation of molybdenum in soil samples from forests in Arizona and New Jersey. We show that in the leaf litter layer, most of the molybdenum forms strong complexes with plant-derived tannins and tannin-like compounds; molybdenum binds to these organic ligands across a wide pH range. In deeper soils, molybdenum binds to both iron oxides and natural organic matter. We suggest that the molybdenum bound to organic matter can be captured by small complexing agents that are released by nitrogen-fixing bacteria; the molybdenum can then be incorporated into nitrogenase. We conclude that the binding of molybdenum to natural organic matter helps prevent leaching of molybdenum, and is thus a critical step in securing new nitrogen in terrestrial ecosystems.

  16. Formation of polished surface of Bi and Sb chalcogenides in pickling compositions K2Cr2O7–HBr

    Directory of Open Access Journals (Sweden)

    Pavlovich I. I.

    2011-12-01

    Full Text Available The polishing etchants were developed and recommendations were given as to their use for processing of semiconductor materials which are used for the manufacture of work items of thermoelectric devices.

  17. Electrical resistivity of sputtered molybdenum films

    International Nuclear Information System (INIS)

    Nagano, J.

    1980-01-01

    The electrical resistivity of r.f. sputtered molybdenum films of thickness 5-150 nm deposited on oxidized silicon substrates was resolved into the three electron scattering components: isotropic background scattering, scattering at grain boundaries and scattering at surfaces. It was concluded that the isotropic background scattering is almost equal to that of bulk molybdenum and is not influenced by sputtering and annealing conditions. When the film thickness is sufficient that surface scattering can be ignored, the decrease in film resistivity after annealing is caused by the decrease in scattering at the grain boundaries for zero bias sputtered films, and is caused by an increase of the grain diameter for r.f. bias sputtered films. (Auth.)

  18. Directly polished lightweight aluminum mirror

    Science.gov (United States)

    ter Horst, Rik; Tromp, Niels; de Haan, Menno; Navarro, Ramon; Venema, Lars; Pragt, Johan

    2017-11-01

    During the last ten years, Astron has been a major contractor for the design and manufacturing of astronomical instruments for Space- and Earth based observatories, such as VISIR, MIDI, SPIFFI, X-Shooter and MIRI. Driven by the need to reduce the weight of optically ultra-stiff structures, two promising techniques have been developed in the last years: ASTRON Extreme Lightweighting [1][2] for mechanical structures and an improved Polishing Technique for Aluminum Mirrors. Using one single material for both optical components and mechanical structure simplifies the design of a cryogenic instrument significantly, it is very beneficial during instrument test and verification, and makes the instrument insensitive to temperature changes. Aluminum has been the main material used for cryogenic optical instruments, and optical aluminum mirrors are generally diamond turned. The application of a polishable hard top coating like nickel removes excess stray light caused by the groove pattern, but limits the degree of lightweighting of the mirrors due to the bi-metal effect. By directly polishing the aluminum mirror surface, the recent developments at Astron allow for using a non-exotic material for light weighted yet accurate optical mirrors, with a lower surface roughness ( 1nm RMS), higher surface accuracy and reduced light scattering. This paper presents the techniques, obtained results and a global comparison with alternative lightweight mirror solutions. Recent discussions indicate possible extensions of the extreme light weight technology to alternative materials such as Zerodur or Silicon Carbide.

  19. Elastic emission polishing

    Energy Technology Data Exchange (ETDEWEB)

    Loewenthal, M.; Loseke, K.; Dow, T.A.; Scattergood, R.O.

    1988-12-01

    Elastic emission polishing, also called elastic emission machining (EEM), is a process where a stream of abrasive slurry is used to remove material from a substrate and produce damage free surfaces with controlled surface form. It is a noncontacting method utilizing a thick elasto-hydrodynamic film formed between a soft rotating ball and the workpiece to control the flow of the abrasive. An apparatus was built in the Center, which consists of a stationary spindle, a two-axis table for the workpiece, and a pump to circulate the working fluid. The process is controlled by a programmable computer numerical controller (CNC), which presently can operate the spindle speed and movement of the workpiece in one axis only. This apparatus has been used to determine material removal rates on different material samples as a function of time, utilizing zirconium oxide (ZrO{sub 2}) particles suspended in distilled water as the working fluid. By continuing a study of removal rates the process should become predictable, and thus create a new, effective, yet simple tool for ultra-precision mechanical machining of surfaces.

  20. Study on chemical mechanical polishing of silicon wafer with megasonic vibration assisted.

    Science.gov (United States)

    Zhai, Ke; He, Qing; Li, Liang; Ren, Yi

    2017-09-01

    Chemical mechanical polishing (CMP) is the primary method to realize the global planarization of silicon wafer. In order to improve this process, a novel method which combined megasonic vibration to assist chemical mechanical polishing (MA-CMP) is developed in this paper. A matching layer structure of polishing head was calculated and designed. Silicon wafers are polished by megasonic assisted chemical mechanical polishing and traditional chemical mechanical polishing respectively, both coarse polishing and precision polishing experiments were carried out. With the use of megasonic vibration, the surface roughness values Ra reduced from 22.260nm to 17.835nm in coarse polishing, and the material removal rate increased by approximately 15-25% for megasonic assisted chemical mechanical polishing relative to traditional chemical mechanical polishing. Average Surface roughness values Ra reduced from 0.509nm to 0.387nm in precision polishing. The results show that megasonic assisted chemical mechanical polishing is a feasible method to improve polishing efficiency and surface quality. The material removal and finishing mechanisms of megasonic vibration assisted polishing are investigated too. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. The study of optimization on process parameters of high-accuracy computerized numerical control polishing

    Science.gov (United States)

    Huang, Wei-Ren; Huang, Shih-Pu; Tsai, Tsung-Yueh; Lin, Yi-Jyun; Yu, Zong-Ru; Kuo, Ching-Hsiang; Hsu, Wei-Yao; Young, Hong-Tsu

    2017-09-01

    Spherical lenses lead to forming spherical aberration and reduced optical performance. Consequently, in practice optical system shall apply a combination of spherical lenses for aberration correction. Thus, the volume of the optical system increased. In modern optical systems, aspherical lenses have been widely used because of their high optical performance with less optical components. However, aspherical surfaces cannot be fabricated by traditional full aperture polishing process due to their varying curvature. Sub-aperture computer numerical control (CNC) polishing is adopted for aspherical surface fabrication in recent years. By using CNC polishing process, mid-spatial frequency (MSF) error is normally accompanied during this process. And the MSF surface texture of optics decreases the optical performance for high precision optical system, especially for short-wavelength applications. Based on a bonnet polishing CNC machine, this study focuses on the relationship between MSF surface texture and CNC polishing parameters, which include feed rate, head speed, track spacing and path direction. The power spectral density (PSD) analysis is used to judge the MSF level caused by those polishing parameters. The test results show that controlling the removal depth of single polishing path, through the feed rate, and without same direction polishing path for higher total removal depth can efficiently reduce the MSF error. To verify the optical polishing parameters, we divided a correction polishing process to several polishing runs with different direction polishing paths. Compare to one shot polishing run, multi-direction path polishing plan could produce better surface quality on the optics.

  2. Mechanical properties of molybdenum coated with titanium carbide film

    International Nuclear Information System (INIS)

    Shikama, T.; Shinno, H.; Fukutomi, M.; Fujitsuka, M.; Okada, M.

    1983-01-01

    TiC-coated molybdenum is mechanically tensile tested. The 6 μm thick TiC-coated molybdenum has a higher 0.2% proof strength with a slight decrease in uniform and rupture elongation than the uncoated one. This strengthening effect of the TiC coating can be explained by the constrained effect of the high strength TiC film. The 1.2 μm thick TiC-coated molybdenum starts its plastic deformation at a lower stress than the uncoated one. Also, the coating makes the stress-strain curve more smooth. These effects are attributed to the surface effect, namely, that the interface between the molybdenum substrate and the strong and brittle TiC film acts as a strong dislocation source. The compressive stress in the TiC film will also help the start of plastic deformation at lower external stresses. (author)

  3. Change of mechanical properties of molybdenum after chemical heat treatment

    International Nuclear Information System (INIS)

    Skuratov, L.P.; Yatsimirskij, V.K.; Kirillova, N.V.

    1987-01-01

    Gaseous media (argon, ammonia, nitrogen-hydrogen-ammonia mixture) are studied for their effect on mechanical characteristics of molybdenum at temperatures up to 1000 deg C. It is established that the highest hardening occurs when molybdenum is esposed in the nitrogen-hydrogen medium, while the highest lost of strength takes place in the ammonia medium. An increase of the ammonia concentration in nitrogen-hydrogen-ammonia mixture promotes regular increasing of the deformation rate. With ammonia concentration of 33.3% the gaseous mixture acts the same as pure ammonia. Change of physical-and-mechanical properties of molybdenum under the action of nitrogen-containing gaseous media is associated with formation of molybdenum compounds with nitrogen. During nitriding in ammonia an internal (volume) nitriding proceeds while in the medium of nitrogen-hydrogen mixture surface nitride layers form

  4. Polish Cartographical Review

    Directory of Open Access Journals (Sweden)

    Nedjeljko Frančula

    2017-07-01

    Full Text Available The Polish Cartographical Review (PCR journal has been published in English four times a year since 2015. The journal is in open access and it is published by De Gruyter Open. It is edited by Polish scientists in collaboration with international experts.

  5. Preparing polished crystal slices with high precision orientation

    DEFF Research Database (Denmark)

    Mathiesen, S. Ipsen; Gerward, Leif; Pedersen, O.

    1974-01-01

    A polishing procedure is described which utilizes a high precision Laue technique for crystal orientation. Crystal slices with their final polished surfaces parallel to a crystallographic plane within 0.02° can be prepared. ©1974 The American Institute of Physics......A polishing procedure is described which utilizes a high precision Laue technique for crystal orientation. Crystal slices with their final polished surfaces parallel to a crystallographic plane within 0.02° can be prepared. ©1974 The American Institute of Physics...

  6. Conformal polishing approach: Tool footprint analysis

    Directory of Open Access Journals (Sweden)

    José A Dieste

    2016-02-01

    Full Text Available Polishing process is one of the most critical manufacturing processes during a metal part production because it determines the final quality of the product. Free-form surface polishing is a handmade process with lots of rejected parts, scrap generation and time and energy consumption. Two different research lines are being developed: prediction models of the final surface quality parameters and an analysis of the amount of material removed depending on the polishing parameters to predict the tool footprint during the polishing task. This research lays the foundations for a future automatic conformal polishing system. It is based on rotational and translational tool with dry abrasive in the front mounted at the end of a robot. A tool to part concept is used, useful for large or heavy workpieces. Results are applied on different curved parts typically used in tooling industry, aeronautics or automotive. A mathematical model has been developed to predict the amount of material removed in function of polishing parameters. Model has been fitted for different abrasives and raw materials. Results have shown deviations under 20% that implies a reliable and controllable process. Smaller amount of material can be removed in controlled areas of a three-dimensional workpiece.

  7. Abrasive wear mechanisms and surface layer structure of refractory materials after mechanical working

    International Nuclear Information System (INIS)

    Milman, Y.V.; Lotsko, D.V.

    1989-01-01

    The mechanisms of abrasive wear and surface layer structure formation after different kinds of mechanical working are considered in terms of fracture and plastic deformation mechanisms for various refractory materials. The principles for classification of abrasive wear mechanisms are proposed, the four types of wear mechanisms are distinguished for various combinations of fractures and plastic deformation types. The concept of characteristic deformation temperature t * (knee temperature) is used. Detailed examples are given of investigating the surface layer structures in grinded crystals of sapphire and molybdenum. The amorphisation tendency of the thinnest surface layer while mechanical polishing is discussed separately. 19 refs., 11 figs., 2 tabs. (Author)

  8. Polishing for glass ceramics: which protocol?

    Science.gov (United States)

    Silva, Tânia Mara da; Salvia, Ana Carolina Rodrigues Danzi; Carvalho, Rodrigo Furtado de; Pagani, Clovis; Rocha, Daniel Maranha da; Silva, Eduardo Galera da

    2014-07-01

    The execution of adjustments on ceramic restorations is sometimes necessary for either correction of occlusion and/or inadequate contours or esthetical improvements. Clinically, the surfaces undergo weariness through fine grinding diamond burs which remove the superficial glazing layer. Several materials for ceramic polishing have been used in an attempt to reach a satisfactory surface smoothness. The aim of this study was to perform a literature review on different polishing protocols of several dental ceramics. This is a literature review performed through scientific articles published between 2004 and 2012, indexed in MEDLINE, PubMed and Scielo databases. The study selected and analyzed a total of 20 relevant articles that evaluated different types of ceramics, polishing treatment and surface roughness. After an extensive literature review, this study observed: 1 - after the rupture of the glazing layer due to the adjustments of the restorations, the best choice for the polishing of the surface will depend on the type of ceramics used; 2 - glazing procedure provide excellent results regarding to the superficial smoothness; however, if reglazing is impossible, either abrasive rubber cups/points or sandpaper discs followed by the use of diamond polishing pastes results in a satisfactory superficial smoothness; 3 - clinical studies that take into account the behavior of the protocols polishing are scarce and should be encouraged; 4 - the large number of variables influence the final outcome of polishing should be considered. The necessity in standardization of methodologies to enable a comparison among researches. Copyright © 2014 Japan Prosthodontic Society. Published by Elsevier Ltd. All rights reserved.

  9. The wear of polished and glazed zirconia against enamel.

    Science.gov (United States)

    Janyavula, Sridhar; Lawson, Nathaniel; Lawson, Nathaniel; Cakir, Deniz; Beck, Preston; Ramp, Lance C; Burgess, John O

    2013-01-01

    The wear of tooth structure opposing anatomically contoured zirconia crowns requires further investigation. The purpose of this in vitro study was to measure the roughness and wear of polished, glazed, and polished then reglazed zirconia against human enamel antagonists and compare the measurements to those of veneering porcelain and natural enamel. Zirconia specimens were divided into polished, glazed, and polished then reglazed groups (n=8). A veneering porcelain (Ceramco3) and enamel were used as controls. The surface roughness of all pretest specimens was measured. Wear testing was performed in the newly designed Alabama wear testing device. The mesiobuccal cusps of extracted molars were standardized and used as antagonists. Three-dimensional (3D) scans of the specimens and antagonists were obtained at baseline and after 200 000 and 400 000 cycles with a profilometer. The baseline scans were superimposed on the posttesting scans to determine volumetric wear. Data were analyzed with a 1-way ANOVA and Tukey Honestly Significant Difference (HSD) post hoc tests (α=.05) Surface roughness ranked in order of least rough to roughest was: polished zirconia, glazed zirconia, polished then reglazed zirconia, veneering porcelain, and enamel. For ceramic, there was no measureable loss on polished zirconia, moderate loss on the surface of enamel, and significant loss on glazed and polished then reglazed zirconia. The highest ceramic wear was exhibited by the veneering ceramic. For enamel antagonists, polished zirconia caused the least wear, and enamel caused moderate wear. Glazed and polished then reglazed zirconia showed significant opposing enamel wear, and veneering porcelain demonstrated the most. Within the limitations of the study, polished zirconia is wear-friendly to the opposing tooth. Glazed zirconia causes more material and antagonist wear than polished zirconia. The surface roughness of the zirconia aided in predicting the wear of the opposing dentition

  10. Direct polishing of aluminum mirrors with higher quality and accuracy.

    Science.gov (United States)

    Yin, Ziqiang; Yi, Zhang

    2015-09-10

    Diamond-turned aluminum mirrors have been widely used in modern optical systems. However, the machined surfaces have characteristic periodic tool marks, which contribute to reduced optical performance by creating effects such as scattering and distortion. This paper develops a new polishing technology to polish aluminum mirrors directly to remove tool marks and improve surface quality and surface accuracy. A Taguchi experiment was used to obtain optimal polishing conditions for reducing surface roughness, and computer-controlled optical surfacing technology was employed for form correction of aluminum mirrors.

  11. Technological Advances of Robot Assisted Polishing

    DEFF Research Database (Denmark)

    Lazarev, Ruslan; Top, Søren; Grønbæk, Jens

    The efficient polishing of surfaces is very important in mould and die industry. Fine abrasive processes are widely used in industry for the first steps for the production of tools of high quality in terms of finishing accuracy, form and surface integrity. While manufacturing of most components r...

  12. Electrochemical concentration of molybdenum in the form of a compound with epsilon-caprolactam

    Energy Technology Data Exchange (ETDEWEB)

    Popkova, G.N.; Brainina, K.Z.; Fedorova, N.D.; Fokina, L.S.

    1985-05-20

    This paper is devoted to an investigation of the possibilities of using epsilon-caprolactam for the electrochemical concentration of molybdenum on the surface of a graphite electrode and the development of a method of determining microgram quantities of molybdenum in the materials of ferrous metallurgy without the removal of accompanying components.

  13. On molybdenum (6) alcoholates

    International Nuclear Information System (INIS)

    Turova, N.Ya.; Kessler, V.G.

    1990-01-01

    Synthesis techniques for molybdenum (6) alcoholates of MoO(OR) 4 (1) and MoO 2 (OR) 2 (2) series by means of exchange interaction of corresponding oxychloride with MOR (M=Li, Na) are obtained. These techniques have allowed to prepare 1(R=Me, Et, i-Pr) and 2(R=Me, Et) with 70-98 % yield. Methylates are also prepared at ether interchange of ethylates by methyl alcohol. Metal anode oxidation in corresponding alcohol may be used for 1 synthesis. Physicochemical properties of both series alcoholates, solubility in alcohols in particular, depend on their formation conditions coordination polymerism. Alcoholates of 1 are rather unstable and tend to decomposition up to 2 and ether. It is suggested to introduce NaOR microquantities to stabilize those alcoholates

  14. Molybdenum Tube Characterization report

    Energy Technology Data Exchange (ETDEWEB)

    Beaux II, Miles Frank [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Usov, Igor Olegovich [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2017-02-07

    Chemical vapor deposition (CVD) techniques have been utilized to produce free-standing molybdenum tubes with the end goal of nuclear fuel clad applications. In order to produce tubes with properties desirable for this application, deposition rates were lowered requiring long deposition durations on the order of 50 hours. Standard CVD methods as well as fluidized-bed CVD (FBCVD) methods were applied towards these objectives. Characterization of the tubes produced in this manner revealed material suitable for fuel clad applications, but lacking necessary uniformity across the length of the tubes. The production of freestanding Mo tubes that possess the desired properties across their entire length represents an engineering challenge that can be overcome in a next iteration of the deposition system.

  15. Buffered Electrochemical Polishing of Niobium

    Energy Technology Data Exchange (ETDEWEB)

    Ciovati, Gianluigi [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Tian, Hui [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); College of William and Mary, Williamsburg, VA (United States); Corcoran, Sean [Virginia Polytechnic Inst. and State Univ. (Virginia Tech), Blacksburg, VA (United States)

    2011-03-01

    The standard preparation of superconducting radio-frequency (SRF) cavities made of pure niobium include the removal of a 'damaged' surface layer, by buffered chemical polishing (BCP) or electropolishing (EP), after the cavities are formed. The performance of the cavities is characterized by a sharp degradation of the quality factor when the surface magnetic field exceeds about 90 mT, a phenomenon referred to as 'Q-drop.' In cavities made of polycrystalline fine grain (ASTM 5) niobium, the Q-drop can be significantly reduced by a low-temperature (? 120 °C) 'in-situ' baking of the cavity if the chemical treatment was EP rather than BCP. As part of the effort to understand this phenomenon, we investigated the effect of introducing a polarization potential during buffered chemical polishing, creating a process which is between the standard BCP and EP. While preliminary results on the application of this process to Nb cavities have been previously reported, in this contribution we focus on the characterization of this novel electrochemical process by measuring polarization curves, etching rates, surface finish, electrochemical impedance and the effects of temperature and electrolyte composition. In particular, it is shown that the anodic potential of Nb during BCP reduces the etching rate and improves the surface finish.

  16. Studies on polishing of Ti and Ag-Pd-Cu-Au alloy with five dental abrasives.

    Science.gov (United States)

    Hirata, T; Nakamura, T; Takashima, F; Maruyama, T; Taira, M; Takahashi, J

    2001-08-01

    Titanium (Ti) and Ag-Pd-Cu-Au alloy were examined for their polishing behaviour by conducting manually controlled polishing tests using five dental abrasives [carborundum point (CR) and silicone points (R1 and R2)] driven by a high torque micromotor with rotational speeds ranging from 2000 to 15 000 r.p.m. Polishing of Ti resulted in less volume of removal upon polishing, a rougher surface and larger loss of abrasives, compared with polishing of Ag-Pd-Cu-Au alloy. Polishing of Ti with a rotational speed of 15 000 r.p.m. led to the largest volume of removal upon polishing, whilst that of 10 000 r.p.m. produced the optimal volume for Ag-Pd-Cu-Au alloy. It was concluded that Ti was much more difficult to polish, requiring special care (e.g. frequent exchange of abrasives). Development of new abrasives for polishing Ti is required.

  17. 3D arrays of molybdenum sulphide nanosheets on Mo meshes: Efficient electrocatalysts for hydrogen evolution reaction

    International Nuclear Information System (INIS)

    Xu, Yan; Zheng, Chong; Wang, Sibo; Hou, Yidong

    2015-01-01

    3D arrays of molybdenum sulphide nanosheets on Mo mesh exhibited enhanced electro-catalytic activity for hydrogen evolution reaction. - Highlights: • 3D arrays of molybdenum sulphide nanosheets were obtained by a facile hydrothermal method. • The mesh structure could be beneficial to promote the electrolyte diffusion onto the electrode surface and thus promote the electron transfer. • 3D arrays of molybdenum sulphide nanosheets demonstrate an enhanced HER activity with a low onset overpotential of 120 mV and a Tafel slope of 46 mV/dec. - Abstract: Molybdenum sulphide has emerged as a promising electrocatalyst for hydrogen evolution reaction (HER). Toward further improving its activity, tremendous efforts have been made to preferentially expose active edge sites of molybdenum sulphide-based catalysts by engineering their surface structure. In this work, 3D arrays of molybdenum sulphide nanosheets were synthesized by hydrothermal treatment of Mo mesh in aqueous thiourea solution. Their compositional, morphological and structural properties as well as electrocatalytic activities were investigated in details. The results reveal that 3D arrays of molybdenum sulphide nanosheets demonstrate an enhanced HER activity with a low onset overpotential of 120 mV and a Tafel slope of 46 mV/dec, which is superior to that of 2D arrays molybdenum sulphide nanosheets grown on Mo foil. The high activity for HER can be ascribed to the superstructure of the catalysts with a large fraction of edge sites and a high surface area

  18. Functional Median Polish

    KAUST Repository

    Sun, Ying

    2012-08-03

    This article proposes functional median polish, an extension of univariate median polish, for one-way and two-way functional analysis of variance (ANOVA). The functional median polish estimates the functional grand effect and functional main factor effects based on functional medians in an additive functional ANOVA model assuming no interaction among factors. A functional rank test is used to assess whether the functional main factor effects are significant. The robustness of the functional median polish is demonstrated by comparing its performance with the traditional functional ANOVA fitted by means under different outlier models in simulation studies. The functional median polish is illustrated on various applications in climate science, including one-way and two-way ANOVA when functional data are either curves or images. Specifically, Canadian temperature data, U. S. precipitation observations and outputs of global and regional climate models are considered, which can facilitate the research on the close link between local climate and the occurrence or severity of some diseases and other threats to human health. © 2012 International Biometric Society.

  19. Development of a multisensory arm for process monitoring in Robot Assisted Polishing

    DEFF Research Database (Denmark)

    Pilny, Lukas; Dalla Costa, Giuseppe; Bissacco, Giuliano

    2015-01-01

    Robot Assisted Polishing (RAP) process is capable of achieving surface roughness down to Sa 10 nm on industrial components. In RAP, a robot arm carries a polishing module with controlled contact force utilizing oscillating or rotating tools. In this work a multisensory polishing arm with integrated...

  20. Molybdenum protective coatings adhesion to steel substrate

    Science.gov (United States)

    Blesman, A. I.; Postnikov, D. V.; Polonyankin, D. A.; Teplouhov, A. A.; Tyukin, A. V.; Tkachenko, E. A.

    2017-06-01

    Protection of the critical parts, components and assemblies from corrosion is an urgent engineering problem and many other industries. Protective coatings’ forming on surface of metal products is a promising way of corrosionprevention. The adhesion force is one of the main characteristics of coatings’ durability. The paper presents theoretical and experimental adhesion force assessment for coatings formed by molybdenum magnetron sputtering ontoa steel substrate. Validity and reliability of results obtained by simulation and sclerometry method allow applying the developed model for adhesion force evaluation in binary «steel-coating» systems.

  1. Behaviour of helium after implantation in molybdenum

    International Nuclear Information System (INIS)

    Viaud, C.; Maillard, S.; Carlot, G.; Valot, C.; Gilabert, E.; Sauvage, T.; Peaucelle, C.; Moncoffre, N.

    2009-01-01

    This study deals with the behaviour of helium in a molybdenum liner dedicated to the retention of fission products. More precisely this work contributes to evaluate the release of implanted helium when the gas has precipitated into nanometric bubbles close to the free surface. A simple model dedicated to calculate the helium release in such a condition is presented. The specificity of this model lays on the assumption that the gas is in equilibrium with a simple distribution of growing bubbles. This effort is encouraging since the calculated helium release fits an experimental dataset with a set of parameters in good agreement with the literature

  2. Purification of molybdenum

    International Nuclear Information System (INIS)

    Cheresnowsky, M.J.; Brunelli, T.A.; Kim, T.K.

    1987-01-01

    A method for purifying molybdenum is described comprising: (a) adding to an ammoniacal ammonium molybdate solution which is at a pH of from about 8.5 to about 11 and which contains the impurities of phosphorus and arsenic with the phosphorus concentration being from about 0.01 to about 0.12 g/l, a soluble magnesium salt to form a precipitate comprising magnesium ammonium salts of the phosphorus and the arsenic, and to form a purified ammonium molybdate solution, with the amount of the magnesium salt being added in an amount sufficient to result in a concentration of from about 0.005 to about 0.04 moles Mg/l in the ammoniacal ammonium molybdate solution, and the purified solution containing no greater than about 0.01 g P/l; (b) separating the precipitate from the purified ammonium molybdate solution; and (c) contacting the purified ammonium molybdate solution with a chelating cation exchange resin supplying a sufficient amount of ammonium as the cation to remove the major portion of the magnesium ions from the purified solution and form a further purified ammonium molybdate solution

  3. Lattice plane spacing change in hardened layer of chrome molybdenum steel after carburizing and quenching

    International Nuclear Information System (INIS)

    Sakaida, Yoshihisa; Kawauchi, Motonori; Shobu, Takahisa

    2011-01-01

    Block specimens of chrome molybdenum steel with 0.20 mass% C, SCM420, were carburized in carrier gas and quenched in oil bath. The hardness and carbon content gradients in the hardened layer were measured experimentally. The carburized surface of one block specimen was gradually removed by electrolytic polishing. Ten thin plates were cut from the total case depth of the other block specimen. An experimental method to determine the stress-free lattice plane spacing of the hardened layer was examined using x-ray and neutron radiations. As a result, the stress-free lattice plane spacing change in the hardened layer could be determined successfully by measuring neutron diffraction peaks from Fe-211 of the thin plates during rotating ±90deg around the specimen axis. Using x-ray, the stress-free lattice plane spacing at the carburized surface could be also determined by measuring the 2θ-sin 2 ψ diagrams of either removed surface of block specimen or thin plate. However, under the carburized surface, the K α2 diffraction from the heat-treated eutectoid phase was superimposed on x-ray diffraction peak because the subsurface microstructure was composed of martensitic and heat-treated eutectoid phases. The stress-free lattice plane spacing under the carburized surface could not be determined using x-ray. Furthermore, the stress-free lattice plane spacing of Fe-211 was found to decrease with increasing the distance from the carburized surface and be expressed by the cubic function of the carbon content in the hardened layer. (author)

  4. Growth of molybdenum disulphide using iodine as transport material

    Indian Academy of Sciences (India)

    analysis. The grown crystals were examined under the optical zoom microscope for their surface microstructure study. Keywords. Single crystals; chemical ... structure of some complex compounds of molybdenum is not clear and also the ... powder (purity: 99.95%) and sulphur powder (purity: 99.95%) were taken in quartz.

  5. Nitrogen reduction: Molybdenum does it again

    Science.gov (United States)

    Schrock, Richard R.

    2011-02-01

    Nature reduces dinitrogen under mild conditions using nitrogenases, the most active of which contains molybdenum and iron. The only abiological dinitrogen reduction catalyst that avoids the harsh conditions of the Haber-Bosch process contains just molybdenum.

  6. Feasibility for separation of stable and radioisotope of molybdenum isotopes with bio filter using microorganism

    International Nuclear Information System (INIS)

    Ghafourain, H.; Shams Rafiee, M.; Mazaheri Tehrani, M.; Ahmadi, A.; Nafar, A.

    2003-01-01

    In this study 23 bacterial strains were isolated, purified and investigated from samples of radioactive polluted water collected from different areas in Ramsar, soils of Hormoz Island, cooper and molybdenum concentrated and various places of copper Sarcheshmeh mines. Among the isolated strains from samples that were investigated, isolated strains from copper Sarcheshmeh mines showed their growth ability at the environment up to 1000 ppm molybdenum and presented a more adsorption ability of molybdenum in relation to other strains. In the P H adsorption study, the optimum value of P H =4 was selected. The effect of molybdenum concentrated in the adsorption process with 50 to 1000 ppm of molybdenum was investigated and results shown that the highest adsorption is up to 200 ppm with 40% of molybdenum. In dynamics experiments of purified strains from soil samples of copper Sarcheshmeh mines showed that the bio masses were saturated almost 95% within 30 minutes. The average dry weight of bacteria's were 0.1-0.7 gr per liter of environment and the adsorption capacity of bio masses varied from 50 to 304 mg molybdenum gr -1 dry bio masses. In comparison with the adsorption of resisting in high concentration of molybdenum with primary isolated strains were definite that the primary strains of 26-90% and resisting strains of 3-77% removed the molybdenum from 200 ppm. Therefor, the primary strains presented the higher adsorption capacity from the existing molybdenum molybdenum which proved the occupation of some Molybdenum adsorption sites on the surface of resisting bacteria's cell on the adaption time. Although there is still no proper definition about the mechanism of Molybdenum adsorption, but by consideration of the optimum P H adsorption, we should state that the relative strains would mainly adsorb the kinds of polymeric anion and molybdate ions. The goal in the first stage of this research was to study the scope of molybdenum adsorption by isolated strains from soils

  7. Super Polishing of Aluminum 6061-T6 Mirrors, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — An innovative 2D super-polishing process for Aluminum 6061-T6 planar mirrors which removes diamond point turning (DPT) grooves and attains rms surface finishes below...

  8. Method of molybdenum kinetic determination

    International Nuclear Information System (INIS)

    Krejngol'd, S.U.; Dzotsenidze, N.E.; Ruseishviyai, T.G.; Nelen', I.M.

    1980-01-01

    The method molybdenum kinetic determination according to oxidation of pyrogallol with bromate in the medium of 0.05-0.15 M perchloric or sulphuric acids is presented. 1 mg of Ni, Co, Mn, Mg, Zn, Cr(3); 100 μg of Ca, Al, Cu, 10 μg of Cr(4), W; 10 μg of Fe in the presence of 22x10 - 4 M solution of EDTA, as well as 10 - 4 M solutions of chlorides and fluorides, 10 - 5 M solutions of bromides do not interfere with molybdenum determination using the given method. The method is rather simple, it takes 30 min to carry out the analysis. Determination limit of molybdenum constitutes 0.01 μg/ml

  9. Isotope analysis of molybdenum in selected minerals

    International Nuclear Information System (INIS)

    Becker, S.; Dietze, H.J.

    1980-01-01

    An analytical method is described for the mass spectrometric determination of molybdenum abundance values. The results of analyses of three molybdenum mineral samples are presented and compared with the results of other authors. It is shown that the fine variations of molybdenum in natural minerals cannot be analysed with currently available mass spectrometers

  10. Evaluation of Molybdenum as a Surrogate for Iridium in the GPHS Weld Development

    Energy Technology Data Exchange (ETDEWEB)

    Stine, Andrew Martin [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Pierce, Stanley W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Moniz, Paul F. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2015-10-17

    The welding equipment used for welding iridium containers (clads) at Los Alamos National Laboratory is twenty five years old and is undergoing an upgrade. With the upgrade, there is a requirement for requalification of the welding process, and the opportunity for process improvement. Testing of the new system and requalification will require several welds on iridium test parts and clads, and any efforts to improve the process will add to the need for iridium parts. The extreme high cost of iridium imposes a severe limitation on the extent of test welding that can be done. The 2 inch diameter, 0.027 inch thick, iridium blank disc that the clad cup is formed from, is useful for initial weld trials, but it costs $5000. The development clad sets needed for final tests and requalification cost $15,000 per set. A solution to iridium cost issue would be to do the majority of the weld development on a less expensive surrogate metal with similar weld characteristics. One such metal is molybdenum. Since its melting index (melting temperature x thermal conductivity) is closest to iridium, welds on molybdenum should be similar in size for a given weld power level. Molybdenum is inexpensive; a single 2 inch molybdenum disc costs only $9. In order to evaluate molybdenum as a surrogate for iridium, GTA welds were first developed to provide full penetration on 0.030 inch thick molybdenum discs at speeds of 20, 25, and 30 inches per minute (ipm). These weld parameters were then repeated on the standard 0.027 inch thick iridium blanks. The top surface and bottom surface (root) width and grain structure of the molybdenum and iridium welds were compared, and similarities were evident between the two metals. Due to material and thickness differences, the iridium welds were approximately 35% wider than the molybdenum welds. A reduction in iridium weld current of 35% produce welds slightly smaller than the molybdenum welds yet showed that current could be scaled according to molybdenum

  11. Strain-free polished channel-cut crystal monochromators: a new approach and results

    Energy Technology Data Exchange (ETDEWEB)

    Kasman, Elina; Montgomery, Jonathan; Huang, XianRong; Assoufid, Lahsen

    2017-08-23

    The use of channel-cut crystal monochromators has been traditionally limited to applications that can tolerate the rough surface quality from wet etching without polishing. We have previously presented and discussed the motivation for producing channel cut crystals with strain-free polished surfaces [1]. Afterwards, we have undertaken an effort to design and implement an automated machine for polishing channel-cut crystals. The initial effort led to inefficient results. Since then, we conceptualized, designed, and implemented a new version of the channel-cut polishing machine, now called C-CHiRP (Channel-Cut High Resolution Polisher), also known as CCPM V2.0. The new machine design no longer utilizes Figure-8 motion that mimics manual polishing. Instead, the polishing is achieved by a combination of rotary and linear functions of two coordinated motion systems. Here we present the new design of C-CHiRP, its capabilities and features. Multiple channel-cut crystals polished using the C-CHiRP have been deployed into several beamlines at the Advanced Photon Source (APS). We present the measurements of surface finish, flatness, as well as topography results obtained at 1-BM of APS, as compared with results typically achieved when polishing flat-surface monochromator crystals using conventional polishing processes. Limitations of the current machine design, capabilities and considerations for strain-free polishing of highly complex crystals are also discussed, together with an outlook for future developments and improvements.

  12. Strain-free polished channel-cut crystal monochromators: a new approach and results

    Science.gov (United States)

    Kasman, Elina; Montgomery, Jonathan; Huang, XianRong; Lerch, Jason; Assoufid, Lahsen

    2017-08-01

    The use of channel-cut crystal monochromators has been traditionally limited to applications that can tolerate the rough surface quality from wet etching without polishing. We have previously presented and discussed the motivation for producing channel cut crystals with strain-free polished surfaces [1]. Afterwards, we have undertaken an effort to design and implement an automated machine for polishing channel-cut crystals. The initial effort led to inefficient results. Since then, we conceptualized, designed, and implemented a new version of the channel-cut polishing machine, now called C-CHiRP (Channel-Cut High Resolution Polisher), also known as CCPM V2.0. The new machine design no longer utilizes Figure-8 motion that mimics manual polishing. Instead, the polishing is achieved by a combination of rotary and linear functions of two coordinated motion systems. Here we present the new design of C-CHiRP, its capabilities and features. Multiple channel-cut crystals polished using the C-CHiRP have been deployed into several beamlines at the Advanced Photon Source (APS). We present the measurements of surface finish, flatness, as well as topography results obtained at 1-BM of APS, as compared with results typically achieved when polishing flat-surface monochromator crystals using conventional polishing processes. Limitations of the current machine design, capabilities and considerations for strain-free polishing of highly complex crystals are also discussed, together with an outlook for future developments and improvements.

  13. Efficiency of three different polishing methods on enamel and cementum: A scanning electron microscope study.

    Science.gov (United States)

    Chowdhary, Zoya; Mohan, Ranjana

    2018-01-01

    Tooth polishing is an integral part of clinical dentistry. The main purpose of polishing is to smoothen the surface of the tooth and minimize the deposition of plaque to allow a healthy periodontal maintenance postscaling. Today, polishing by different methods is available to a clinician. Traditional bristle brush and rubber-cup polishing are being widely practiced and gradually getting replaced by novel air polisher. Pros and cons of each method should be weighed before its clinical applications. To evaluate and compare the efficiency of three different polishing systems on enamel as well as on cementum surfaces by scanning electron microscope (SEM). A total of 120 samples were divided into three groups randomly - Group 1 (bristle brush), Group 2 (rubber cup), and Group 3 (air polisher) - with 20 samples each of enamel and cementum, which were subdivided into 10 control and 10 test group (subjected to polishing). The samples were analyzed by SEM at ×1000 magnification, and the data obtained were compiled and subjected to statistical analysis. Polishing with bristle brush demonstrated less surface roughness and debris when compared to air polisher at P = 0.58, P = 0.03 for enamel surface and P = 0.003, P = 0.21 for cementum, respectively. The surface roughness was reduced considerably by rubber cup at P = 0.03 for enamel and P = 0.003 for cementum, compared to air polisher at P = 0.99 and P = 0.21 for enamel and cementum, respectively. The results indicate that polishing with rubber cup was more effective and statistically significant when compared to bristle brush polishing and air polisher for the crown and root surface smoothening and debris removal.

  14. Recovery of molybdenum values from dilute solutions

    International Nuclear Information System (INIS)

    Litchfield, J.; Pemsler, J.

    1980-01-01

    A process is described for concentrating the molybdenum values in an aqueous ammoniacal leach liquor. Ferrous ions are added to the liquor in sufficient quantities to saturate the leach liquor and provide an excess sufficient to precipitate a solid complex whose approximate Fe/Mo ratio is 3.5 or greater. The molybdenum values thereinare precipitated as a ferrous hydroxide ammonium molybdate complex. The molybdenum containing precipitate is separated from the aqueous liquor. Acid is added to the separated molybdenum containing precipitate to resolubilize the molybdenum values

  15. HYDROGEN VACANCY INTERACTION IN MOLYBDENUM

    NARCIS (Netherlands)

    Abd El Keriem, M.S.; van der Werf, D.P.; Pleiter, F

    1993-01-01

    Vacancy-hydrogen interaction in molybdenum was investigated by means of the perturbed angular correlation technique, using the isotope In-111 as a probe. The complex InV2 turned out to trap up to two hydrogen atoms: trapping of a single hydrogen atom gives rise to a decrease of the quadrupole

  16. Gel Fabrication of Molybdenum “Beads”

    Energy Technology Data Exchange (ETDEWEB)

    Lowden, Richard Andrew [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Armstrong, Beth L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division; Cooley, Kevin M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Materials Science and Technology Division

    2016-11-01

    Spherical molybdenum particles or “beads” of various diameters are of interest as feedstock materials for the additive manufacture of targets and assemblies used in the production of 99Mo medical isotopes using accelerator technology. Small metallic beads or ball bearings are typically fabricated from wire; however, small molybdenum spheres cannot readily be produced in this manner. Sol-gel processes are often employed to produce small dense microspheres of metal oxides across a broad diameter range that in the case of molybdenum could be reduced and sintered to produce metallic spheres. These Sol-gel type processes were examined for forming molybdenum oxide beads; however, the molybdenum trioxide was chemically incompatible with commonly used gelation materials. As an alternative, an aqueous alginate process being assessed for the fabrication of oxide spheres for catalyst applications was employed to form molybdenum trioxide beads that were successfully reduced and sintered to produce small molybdenum spheres.

  17. Cold-drawing sheet molybdenum at room temperature

    International Nuclear Information System (INIS)

    Shepherd, L.W.

    1975-11-01

    When sheet molybdenum is cold-drawn and annealed, the microstructure recrystallizes, and may cause the metal to become brittle, with loss of ductility and strength. Ten to twenty percent recrystallization can occur to destroy optimum drawing quality of the metal. A recrystallization of 4 to 5 percent is ideal. It is shown that special tooling and controlled annealing can hold recrystallization to optimum levels. Special tooling includes an automatic cycling press that closely controls the rate of draw and gives maximum pressure. A draw sleeve of high carbon steel is used. The draw sleeve can be highly polished to minimize friction and provides an intensifying effect of the ram force over the entire part. Four draw steps are used, with each step followed by an annealing at 925 0 C for 20 minutes. Results of recrystallization analysis show that the ideal five percent recrystallization is achieved with this process

  18. Polish Semantic Parser

    Directory of Open Access Journals (Sweden)

    Agnieszka Grudzinska

    2000-01-01

    Full Text Available Amount of information transferred by computers grows very rapidly thus outgrowing the average man's capability of reception. It implies computer programs increase in the demand for which would be able to perform an introductory classitication or even selection of information directed to a particular receiver. Due to the complexity of the problem, we restricted it to understanding short newspaper notes. Among many conceptions formulated so far, the conceptual dependency worked out by Roger Schank has been chosen. It is a formal language of description of the semantics of pronouncement integrated with a text understanding algorithm. Substantial part of each text transformation system is a semantic parser of the Polish language. It is a module, which as the first and the only one has an access to the text in the Polish language. lt plays the role of an element, which finds relations between words of the Polish language and the formal registration. It translates sentences written in the language used by people into the language theory. The presented structure of knowledge units and the shape of understanding process algorithms are universal by virtue of the theory. On the other hand the defined knowledge units and the rules used in the algorithms ure only examples because they are constructed in order to understand short newspaper notes.

  19. Pseudo-random tool paths for CNC sub-aperture polishing and other applications.

    Science.gov (United States)

    Dunn, Christina R; Walker, David D

    2008-11-10

    In this paper we first contrast classical and CNC polishing techniques in regard to the repetitiveness of the machine motions. We then present a pseudo-random tool path for use with CNC sub-aperture polishing techniques and report polishing results from equivalent random and raster tool-paths. The random tool-path used - the unicursal random tool-path - employs a random seed to generate a pattern which never crosses itself. Because of this property, this tool-path is directly compatible with dwell time maps for corrective polishing. The tool-path can be used to polish any continuous area of any boundary shape, including surfaces with interior perforations.

  20. Evaluation of enamel surface after bracket debonding and polishing Avaliação da superfície do esmalte dentário após a remoção do braquete e polimento

    Directory of Open Access Journals (Sweden)

    Lilian Maria Brisque Pignatta

    2012-08-01

    Full Text Available INTRODUCTION: Preserving the dental enamel structure during removal of orthodontic accessories is a clinician's obligation. Hence the search for an evidence based debonding protocol. OBJECTIVE: to evaluate and compare, by means of scanning electron microscopy (SEM, the effects of four different protocols of bracket debonding and subsequent polishing on enamel surface, and to propose a protocol that minimizes damage to enamel surface. METHODS: Twelve bovine permanent incisors were divided into four groups according to the instrument used for debonding and removal of the adhesive remnant. In groups 1 and 2, brackets were debonded with a straight debonding plier (Ormco Corp., Glendora, California, USA, and in groups 3 and 4, debonding was performed with the instrument Lift-Off (3M Unitek, Monrovia, California, USA. In groups 1 and 3, the adhesive remnant was removed using a long adhesive removing plier (Ormco Corp., Glendora, California, USA and in groups 2 and 4, residual adhesive was removed with a tungsten carbide bur (Beavers Dental at high-speed. After each stage of debonding and polishing, enamel surfaces were replicated and electron micrographs were obtained with 50 and 200X magnification. RESULTS: All four protocols of debonding and polishing caused enamel irregularities. CONCLUSION: Debonding brackets with straight debonding plier, removal of adhesive remnant with a tungsten carbide bur and polishing with pumice and rubber cup was found to be the protocol that caused less damage to enamel surface, therefore this protocol is suggested for debonding brackets.INTRODUÇÃO: a preservação da estrutura de esmalte após a remoção dos acessórios ortodônticos é obrigação do clínico. Portanto, procura-se um protocolo de descolagem com bases científicas. OBJETIVO: objetivou-se avaliar por microscopia eletrônica de varredura (MEV a influência de quatro protocolos de remoção de braquetes e polimento da superfície do esmalte e propor um

  1. Laser polishing of 3D printed mesoscale components

    Energy Technology Data Exchange (ETDEWEB)

    Bhaduri, Debajyoti, E-mail: debajyoti.bhaduri@gmail.com [Department of Mechanical Engineering, School of Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Penchev, Pavel; Batal, Afif; Dimov, Stefan; Soo, Sein Leung [Department of Mechanical Engineering, School of Engineering, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Sten, Stella; Harrysson, Urban [Digital Metal, Höganäs AB, 263 83 Höganäs (Sweden); Zhang, Zhenxue; Dong, Hanshan [School of Metallurgy and Materials, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom)

    2017-05-31

    Highlights: • Process optimisation for laser polishing novel 3D printed SS316L parts. • Evaluating the effects of key polishing parameters on SS316L surface roughness. • Detailed spectroscopic analysis of oxide layer formation due to laser polishing. • Comparative surface integrity analysis of SS parts polished in air and argon. • A maximum reduction in roughness of over 94% achieved at optimised polishing settings. - Abstract: Laser polishing of various engineered materials such as glass, silica, steel, nickel and titanium alloys, has attracted considerable interest in the last 20 years due to its superior flexibility, operating speed and capability for localised surface treatment compared to conventional mechanical based methods. The paper initially reports results from process optimisation experiments aimed at investigating the influence of laser fluence and pulse overlap parameters on resulting workpiece surface roughness following laser polishing of planar 3D printed stainless steel (SS316L) specimens. A maximum reduction in roughness of over 94% (from ∼3.8 to ∼0.2 μm S{sub a}) was achieved at the optimised settings (fluence of 9 J/cm{sup 2} and overlap factors of 95% and 88–91% along beam scanning and step-over directions respectively). Subsequent analysis using both X-ray photoelectron spectroscopy (XPS) and glow discharge optical emission spectroscopy (GDOES) confirmed the presence of surface oxide layers (predominantly consisting of Fe and Cr phases) up to a depth of ∼0.5 μm when laser polishing was performed under normal atmospheric conditions. Conversely, formation of oxide layers was negligible when operating in an inert argon gas environment. The microhardness of the polished specimens was primarily influenced by the input thermal energy, with greater sub-surface hardness (up to ∼60%) recorded in the samples processed with higher energy density. Additionally, all of the polished surfaces were free of the scratch marks, pits, holes

  2. Tracing euxinia by molybdenum concentrations in sediments using handheld X-ray fluorescence spectroscopy (HHXRF)

    DEFF Research Database (Denmark)

    Dahl, Tais W.; Ruhl, Micha; Hammarlund, Emma U.

    2013-01-01

    Elevated molybdenum (Mo) contents in organic-rich sediments are indicative of deposition from an anoxic and sulfide-rich (euxinic) water-column. This can be used for tracing past euxinic conditions in ancient oceans from sedimentary archives. Conventional analytical detection of elevated molybdenum...... obtained Mo concentrations from homogenous powders of the same rocks. Collectively, our data show that HHXRF as a quick and reliable method for the precise and accurate quantification of molybdenum concentrations in both rock powders and at fresh rock surfaces. The non-destructive nature of the HHXRF...

  3. Reel-to-reel substrate tape polishing system

    Energy Technology Data Exchange (ETDEWEB)

    Selvamanickam, Venkat; Gardner, Michael T.; Judd, Raymond D.; Weloth, Martin; Qiao, Yunfei

    2005-06-21

    Disclosed is a reel-to-reel single-pass mechanical polishing system (100) suitable for polishing long lengths of metal substrate tape (124) used in the manufacture of high-temperature superconductor (HTS) coated tape, including multiple instantiations of a polishing station (114) in combination with a subsequent rinsing station (116) arranged along the axis of the metal substrate tape (124) that is translating between a payout spool (110a) and a take-up spool (110b). The metal substrate tape obtains a surface smoothness that is suitable for the subsequent deposition of a buffer layer.

  4. Analysis of molybdenum, tungsten, and vanadium in surface water of the Atlantic Ocean using solid phase extraction with 8-hydroxyquinoline and ICP MS determination

    Science.gov (United States)

    Rimskaya-Korsakova, M. N.; Berezhnaya, E. D.; Dubinin, A. V.

    2017-07-01

    An analytical technique is proposed to determine ultratrace concentrations of Mo, V, and W found in seawater using mass spectrometry with inductively coupled plasma (ICP MS) after preliminary concentration by solid-phase extraction of metal complexes with 8-hydroxyquinoline (8-HQ) on C18 octadecyl silica. The technique utilizes 150 mL of a water sample. A preconcentration factor 50 is obtained. The detection limits are 0.25 nmol/kg, 0.041 nmol/kg, and 5 pmol/kg for Mo, V, and W, respectively. Dissolved Mo, V, and Wconcentrations in surface seawater from Atlantic Ocean transect were determined. The concentrations ranges along the transect were: 91-108 nmol/kg for Mo, 28-35 nmol/kg for V, and 55-75 pmol/kg for W. The Mo/W ratio varied from 1300 to 1800.

  5. Advanced space optics development in freeform optics design, ceramic polishing, rapid and extreme freeform polishing

    Science.gov (United States)

    Geyl, R.; Leplan, H.; Ruch, E.

    2017-09-01

    In this paper Safran-Reosc wants to share with the space community its recent work performed in the domain of space optics. Our main topic is a study about the advantages that freeform optical surfaces can offer to advanced space optics in term of compactness or performances. We have separated smart and extreme freeform in our design exploration work. Our second topic is to answer about the immediate question following: can we manufacture and test these freeform optics? We will therefore present our freeform optics capability, report recent achievement in extreme aspheric optics polishing and introduce to the industrialisation process of large off axis optics polishing for the ESO Extremely Large Telescope primary mirror segments. Thirdly we present our R-SiC polishing layer technology for SiC material. This technique has been developed to reduce costs, risks and schedule in the manufacturing of advanced SiC optics for Vis and IR applications.

  6. The behaviour of molybdenum dialkyldithiocarbamate friction modifier additives

    International Nuclear Information System (INIS)

    Graham, Jocelyn Claire Herries

    2001-01-01

    In recent years there has been growing concern to produce energy-efficient lubricated components and modem engine oil specifications require lubricants to demonstrate fuel efficiency in standardised engine tests. One important method of producing low friction and thus fuel-efficient lubricants is to use oil-soluble, molybdenum-containing, friction modifier additives. In optimal conditions these additives are able to produce very low friction coefficients, in the range 0.045 to 0.075 in boundary lubrication conditions. Very little is known about the chemical and physical mechanisms by which oil soluble molybdenum additives form low friction films in tribological contacts. Information about their activity could lead to optimal use of these additives in lubricants and, therefore, more efficient engine running. The work outlined in this thesis investigated the behaviour of oil-soluble molybdenum additives and showed that these additives were able to effectively reduce friction in the absence of other additives such as ZnDTP. Their activity was shown to be highly concentration and temperature dependent and was also found to be sensitive to the roughness of the contacting surfaces. Raman spectroscopy was used to analyse the chemical nature of molybdenum-containing reaction films and found that friction reduction indubitably arises from the local formation of platelets (diameter 30-50 nm) of MoS 2 . The formation of MoS 2 -rich films was found to occur only during direct asperity-asperity rubbing of the contacting surfaces (this type of contact being especially prevalent in pure sliding contacts). At elevated temperatures and in the presence of oxidising gases the consumption of MoDTC was monitored. MoDTC concentration dropped until the total value fell below a critical level to reduce friction. The study showed that decay rate of molybdenum-containing species was reduced by the addition of peroxide-decomposing antioxidants. (author)

  7. Flexible Molybdenum Electrodes towards Designing Affinity Based Protein Biosensors.

    Science.gov (United States)

    Kamakoti, Vikramshankar; Panneer Selvam, Anjan; Radha Shanmugam, Nandhinee; Muthukumar, Sriram; Prasad, Shalini

    2016-07-18

    Molybdenum electrode based flexible biosensor on porous polyamide substrates has been fabricated and tested for its functionality as a protein affinity based biosensor. The biosensor performance was evaluated using a key cardiac biomarker; cardiac Troponin-I (cTnI). Molybdenum is a transition metal and demonstrates electrochemical behavior upon interaction with an electrolyte. We have leveraged this property of molybdenum for designing an affinity based biosensor using electrochemical impedance spectroscopy. We have evaluated the feasibility of detection of cTnI in phosphate-buffered saline (PBS) and human serum (HS) by measuring impedance changes over a frequency window from 100 mHz to 1 MHz. Increasing changes to the measured impedance was correlated to the increased dose of cTnI molecules binding to the cTnI antibody functionalized molybdenum surface. We achieved cTnI detection limit of 10 pg/mL in PBS and 1 ng/mL in HS medium. The use of flexible substrates for designing the biosensor demonstrates promise for integration with a large-scale batch manufacturing process.

  8. Evaluation of the COMSOL software electro-polishing of samples

    International Nuclear Information System (INIS)

    Bruchon, M.

    2007-01-01

    The niobium electro-polishing is efficient if a viscous layer exists at the surface. In order to define parameters of samples electro-polishing, opened with difficulty to the experiments, the simulation is essential. This report presents works realized with the COMSOL software. The Nernst Planck equations have been associated to the Navier Stockes ones for an incompressible fluid. The study of the potential behaviour on the viscous layer and the mobility value have been detailed. (A.L.B.)

  9. Contamination by slow diffusers in ion implantation processes: The examples of molybdenum and tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Polignano, M.L., E-mail: maria.polignano@st.com [ST Microelectronics, via Olivetti, 2, 20864 Agrate Brianza, MB (Italy); Mica, I., E-mail: isabella.mica@st.com [ST Microelectronics, via Olivetti, 2, 20864 Agrate Brianza, MB (Italy); Barbarossa, F., E-mail: fbarbarossa87@gmail.com [ST Microelectronics, via Olivetti, 2, 20864 Agrate Brianza, MB (Italy); Galbiati, A., E-mail: amos.galbiati@st.com [ST Microelectronics, via Olivetti, 2, 20864 Agrate Brianza, MB (Italy); Grasso, S., E-mail: salvatore.grasso-r2@st.com [ST Microelectronics, via Olivetti, 2, 20864 Agrate Brianza, MB (Italy); Soncini, V., E-mail: vsoncini@micron.com [Micron, via Olivetti, 2, 20864 Agrate Brianza, MB (Italy)

    2015-08-01

    A procedure to measure molybdenum and tungsten contamination in implantation processes by DLTS (Deep Level Transient Spectroscopy) is defined and calibrated for the evaluation of molybdenum and tungsten contaminant dose. The obtained calibrations are used to study molybdenum contamination in BF{sub 2} implantations and tungsten contamination by sputtering from a previously contaminated wafer holder. In molybdenum-implanted samples, the molybdenum level located 0.3 eV above valence band is revealed only. In tungsten-implanted samples, two levels are revealed. One of these levels is the tungsten-related hole trap located 0.4 eV above valence band. The other level does not correspond to any tungsten-related level, however it is related to the presence of tungsten and to the sample preparation process. The SPV (Surface Photovoltage) measurement sensitivity to tungsten contamination was also tested, and it was found much lower than the DLTS sensitivity, due to the low tungsten diffusivity. This procedure was used to evaluate contamination in implantation processes. In BF{sub 2} implantations, in addition to molybdenum, tungsten contamination is found. Molybdenum and tungsten contamination is found in boron implantation too. The tungsten contamination induced by implantation in a previously contaminated implanter was quantified, and the efficiency of arsenic implantation as a decontamination process was tested. Finally, it was shown that TXRF (Total reflection X-ray Fluorescence) is much less sensitive than DLTS for monitoring tungsten contamination.

  10. Contamination by slow diffusers in ion implantation processes: The examples of molybdenum and tungsten

    Science.gov (United States)

    Polignano, M. L.; Mica, I.; Barbarossa, F.; Galbiati, A.; Grasso, S.; Soncini, V.

    2015-08-01

    A procedure to measure molybdenum and tungsten contamination in implantation processes by DLTS (Deep Level Transient Spectroscopy) is defined and calibrated for the evaluation of molybdenum and tungsten contaminant dose. The obtained calibrations are used to study molybdenum contamination in BF2 implantations and tungsten contamination by sputtering from a previously contaminated wafer holder. In molybdenum-implanted samples, the molybdenum level located 0.3 eV above valence band is revealed only. In tungsten-implanted samples, two levels are revealed. One of these levels is the tungsten-related hole trap located 0.4 eV above valence band. The other level does not correspond to any tungsten-related level, however it is related to the presence of tungsten and to the sample preparation process. The SPV (Surface Photovoltage) measurement sensitivity to tungsten contamination was also tested, and it was found much lower than the DLTS sensitivity, due to the low tungsten diffusivity. This procedure was used to evaluate contamination in implantation processes. In BF2 implantations, in addition to molybdenum, tungsten contamination is found. Molybdenum and tungsten contamination is found in boron implantation too. The tungsten contamination induced by implantation in a previously contaminated implanter was quantified, and the efficiency of arsenic implantation as a decontamination process was tested. Finally, it was shown that TXRF (Total reflection X-ray Fluorescence) is much less sensitive than DLTS for monitoring tungsten contamination.

  11. Mechanical properties of electron-beam-melted molybdenum and dilute molybdenum-rhenium alloys

    Science.gov (United States)

    Klopp, W. D.; Witzke, W. R.

    1972-01-01

    A study of molybdenum and three dilute molybdenum-rhenium alloys was undertaken to determine the effects of rhenium on the low temperature ductility and other mechanical properties of molybdenum. Alloys containing 3.9, 5.9, and 7.7 atomic percent rhenium exhibited lower ductile-brittle transition temperatures than did the unalloyed molybdenum. The maximum improvement in the annealed condition was observed for molybdenum - 7.7 rhenium, which had a ductile-brittle transition temperature approximately 200 C (360 F) lower than that for unalloyed molybdenum. Rhenium additions also increased the low and high temperature tensile strengths and the high temperature creep strength of molybdenum. The mechanical behavior of dilute molybdenum-rhenium alloys is similar to that observed for dilute tungsten-rhenium alloys.

  12. Neutron scattering and models: molybdenum

    International Nuclear Information System (INIS)

    Smith, A.B.

    1999-01-01

    A comprehensive interpretation of the fast-neutron interaction with elemental and isotopic molybdenum at energies of le 30 MeV is given. New experimental elemental-scattering information over the incident energy range 4.5 r a rrow 10 MeV is presented. Spherical, vibrational and dispersive models are deduced and discussed, including isospin, energy-dependent and mass effects. The vibrational models are consistent with the ''Lane potential''. The importance of dispersion effects is noted. Dichotomies that exist in the literature are removed. The models are vehicles for fundamental physical investigations and for the provision of data for applied purposes. A ''regional'' molybdenum model is proposed. Finally, recommendations for future work are made

  13. Neutron scattering and models : molybdenum.

    Energy Technology Data Exchange (ETDEWEB)

    Smith, A.B.

    1999-05-26

    A comprehensive interpretation of the fast-neutron interaction with elemental and isotopic molybdenum at energies of {le} 30 MeV is given. New experimental elemental-scattering information over the incident energy range 4.5 {r_arrow} 10 MeV is presented. Spherical, vibrational and dispersive models are deduced and discussed, including isospin, energy-dependent and mass effects. The vibrational models are consistent with the ''Lane potential''. The importance of dispersion effects is noted. Dichotomies that exist in the literature are removed. The models are vehicles for fundamental physical investigations and for the provision of data for applied purposes. A ''regional'' molybdenum model is proposed. Finally, recommendations for future work are made.

  14. CVD molybdenum films of high infrared reflectance

    Energy Technology Data Exchange (ETDEWEB)

    Carver, G. E.

    1979-01-01

    Molybdenum thin films of high infrared reflectance have been deposited by pyrolytic decomposition of molybdenum carbonyl (Mo(CO)/sub 6/), and by hydrogen reduction of molybdenum pentachloride (MoCl/sub 5/). Reflectance values within 0.7% of the reflectance of supersmooth bulk molybdenum have been attained by annealing films of lower reflectance in both reducing and non-reducing atmospheres. All depositions and anneals proceed at atmospheric pressure, facilitating a continuous, flow-through fabrication. These reflectors combine the high temperature stability of molybdenum thin films with the infrared reflectance of a material such as aluminum. Deposition from Mo(CO)/sub 6/ under oxidizing conditions, and subsequent anneal in a reducing atmosphere, results in films that combine high solar absorptance with low thermal emittance. If anti-reflected, black molybdenum films can serve as highly selective single layer photothermal converters. Structural, compositional, and crystallographic properties have been measured after both deposition and anneal.

  15. The involvement of molybdenum in life

    International Nuclear Information System (INIS)

    Williams, R. J. P.; Frausto da Silva, J. J. R.

    2002-01-01

    Quite extraordinarily molybdenum is an essential element in life for the uptake of nitrogen from both nitrogen gas and nitrate, yet it is a relatively rare heavy trace element. It also functions in a few extremely important oxygen-atom transfer reactions at low redox potential. This review poses the question ''Why does life depend upon molybdenum?'' The answer has to be based upon the availability of the element and on chemical superiority in carrying out the essential tasks. We illustrate here the peculiarities of molybdenum chemistry and how they have become part of certain enzymes. The uptake and incorporation of molybdenum are dependent on its availability, selective pumps, and carriers (chaperones), but 4.5 x 10 9 years ago molybdenum was not available when both tungsten and vanadium or even iron were possibly used in its place. While these possibilities are explored, they leave many unanswered questions concerning the selection today of molybdenum

  16. Zirconia-molybdenum disilicide composites

    Science.gov (United States)

    Petrovic, John J.; Honnell, Richard E.

    1991-01-01

    Compositions of matter comprised of molybdenum disilicide and zirconium oxide in one of three forms: pure, partially stabilized, or fully stabilized and methods of making the compositions. The stabilized zirconia is crystallographically stabilized by mixing it with yttrium oxide, calcium oxide, cerium oxide, or magnesium oxide and it may be partially stabilized or fully stabilized depending on the amount of stabilizing agent in the mixture.

  17. Carbon, chromium and molybdenum contents

    International Nuclear Information System (INIS)

    Sinatora, A; Goldenstein, H.; Mei, P.R.; Albertin, E.; Fuoco, R.; Mariotto, C.L.

    1992-01-01

    This work describes solidification experiments on white cast iron, with 15 and 20% of chromium, 2.3, 3.0 and 3.6 % of carbon and 0.0, 1.5 and 2.5 % of molybdenum in test de samples with 30 mm diameter. Measurements were performed on the austenite and eutectic formation arrests, the number of the eutectic carbide particles relative to the total and the eutectic volumes, and the volume fraction of the primary austenite

  18. Study and comparison of analytical methods for dosing molybdenum in uranium-molybdenum alloys

    International Nuclear Information System (INIS)

    Buffereau, M.; Genty, C.; Houin, C.; Lavaud, M.; Leclainche, C.; Levrard, J.; Pichotin, B.; Robichet, J.

    1968-01-01

    Methods to determine molybdenum in uranium-molybdenum alloys are developed by various technic: molecular absorption spectrophotometry, emission spectroscopy, X ray fluorescence, atomic absorption spectrophotometry. After a comparison on samples in which molybdenum content lies between 1 and 10 per cent by weight, one concludes in the interest of some of the exposed methods for routine analysis. (author) [fr

  19. [Lysenkoism in Polish botany].

    Science.gov (United States)

    Köhler, Piotr

    2008-01-01

    Lysenkoism in Poland was never an autonomous phenomenon. The whole array of reasons for which it appeared in Polish science would require a separate study--here it only needs to be pointed out that the major reasons included terror on the part of the security service, lawlessness, the ubiquitous atmosphere of intimidation and terror, censorship, the diminishing sphere of civil liberties, political show trials, propaganda and denunciations. An important role in facilitating the introduction of Lysenkoism was played also by the reorganization of science after World War Two, the isolation of Polish science from science in the West, as well as the damage it had suffered during the war. At first, Lysenkoism was promoted in Poland by a small group of enthusiastic and uncritical proponents. A overview of the events connected with the ten years of Lysenkoism in Poland (end of 1948--beginning of 1958) shows a two-tier picture of how the 'idea' was propagated. The first tier consisted in the activities of the Association of Marxist Naturalists [Koło Przyrodników-Marksistów], which it engaged in since the end of 1948. The Association was later transformed into a Union of Marxist Naturalists, and this in turn merged, in 1952, with the Copernican Society of Polish Naturalists [Polskie Towarzystwo Przyrodników im. Kopernika]. It was that society which promoted Lysenkoism longest, until the end of 1956. The propaganda and training activities of the circle and the society prepared ground for analogous activities of the newly formed Polish Academy of Science (PAN), which--since its very establishment in 1952--engaged in promoting Lysenkoism through its Second Division. These activities were aimed at naturalists, initially at those who were prominent scientists (eg. the conference at Kuźnice, 1950/1951), and then at those who were only starting their academic career (including national courses in new biology at Dziwnów, 1952, or Kortowo, 1953 and 1955). The end to promoting

  20. Edge eigen-stress and eigen-displacement of armchair molybdenum disulfide nanoribbons

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Quan; Li, Xi [Corrosion and Protection Center, Key Laboratory for Environmental Fracture (MOE), University of Science and Technology Beijing, Beijing 100083 (China); Volinsky, Alex A., E-mail: volinsky@usf.edu [Department of Mechanical Engineering, University of South Florida, Tampa, FL 33620 (United States); Su, Yanjing, E-mail: yjsu@ustb.edu.cn [Corrosion and Protection Center, Key Laboratory for Environmental Fracture (MOE), University of Science and Technology Beijing, Beijing 100083 (China)

    2017-05-10

    Edge effects on mechanical properties of armchair molybdenum disulfide nanoribbons were investigated using first principles calculations. The edge eigen-stress model was applied to explain the relaxation process of forming molybdenum disulfide nanoribbon. Edge effects on surface atoms fluctuation degree were obtained from each fully relaxed nanoribbon with different width. Changes of the relaxed armchair molybdenum disulfide nanoribbons structure can be expressed using hexagonal perimeters pattern. Based on the thickness change, relaxed armchair molybdenum disulfide nanoribbons tensile/compression tests were simulated, providing intrinsic edge elastic parameters, such as eigen-stress, Young's modulus and Poisson's ratio. - Highlights: • Edge effects on mechanical properties of armchair MoS{sub 2} nanoribbons were investigated. • Structure changes of different width armchair MoS{sub 2} nanoribbons were obtained. • Tensile/compressive tests were conducted to determine elastic constants. • Mechanical properties are compared for two and three dimensional conditions.

  1. Evaluation of various polishing systems and the phase transformation of monolithic zirconia.

    Science.gov (United States)

    Huh, Yoon-Hyuk; Park, Chan-Jin; Cho, Lee-Ra

    2016-09-01

    Although a well-polished monolithic zirconia surface is essential, insufficient comparative studies on the constituents and efficacy of polishing systems have been conducted. The purpose of this in vitro study was to analyze the abrasive constituents and compare the polishing effectiveness of 6 zirconia polishing systems, including their potential influence on the phase transformation of monolithic zirconia. The compositions of 6 zirconia polishing systems were analyzed using energy dispersive spectroscopy (EDS). Sintered and high-speed ground monolithic zirconia specimens were used as control groups (n=14 specimens per group). Test groups (n=168) were pretreated identically to the control group and arbitrarily divided into 12 groups to examine 6 polishing systems for 2 polishing periods (60 or 120 seconds). The surfaces were characterized by a surface profiler and various analytic techniques, including x-ray diffraction (XRD) analysis. The data were analyzed using 2-way ANOVA and multiple comparisons and the Bonferroni method (α=.05). The abrasives were primarily composed of C, O, and Si. Diamond was identified as the main abrasive and SiC as the supplementary abrasive in the polishing systems. No significant differences were observed for the 60- or 120-second polishing times (P>.05). Four products had significantly lower surface roughness values than the other 2 (Pzirconia specimens. The monolithic zirconia polishing systems contained diamond and SiC abrasives. All zirconia polishing systems showed clinically acceptable results, and 4 systems exhibited lower surface roughness. Phase transformation did not occur during polishing procedure. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

  2. Color stability of nanocomposites polished with one-step systems.

    Science.gov (United States)

    Ergücü, Zeynep; Türkün, L Sebnem; Aladag, Akin

    2008-01-01

    This study compared the color changes of five novel resin composites polished with two one-step polishing systems when exposed to coffee solution. The resin composites tested were Filtek Supreme XT, Grandio, CeramX, Premise and Tetric EvoCeram. A total of 150 discs (30/resin composites, 10 x 2 mm) were fabricated. Ten specimens/resin composites cured under Mylar strips served as the control. The other samples were polished with PoGo and OptraPol discs for 30 seconds using a slow speed handpiece and immersed in coffee (Nescafé) for seven days. Color measurements were made with Vita Easyshade at baseline and after one and seven days. Repeated Measures ANOVA and Bonferroni tests were used for statistical analyses (pGrandio, there were no significant differences between the Mylar and PoGo groups, while the most stain resistant surfaces were attained with OptraPol. Removing the outermost resin layer by polishing procedures is essential to achieving a stain resistant, more esthetically stable surface. One-step polishing systems can be used successfully for polishing nanocomposites.

  3. Subjective Quality of Life of Polish, Polish-Immigrant, and Polish-American Elderly.

    Science.gov (United States)

    Berdes, Celia; Zych, Adam A.

    2000-01-01

    Compares subjective quality of life of elderly Poles living in Poland, and Polish immigrants and Polish-American ethnics living in Chicago as part of a secondary data analysis of a study initially conducted in Poland. Conclusions lend support to the idea that U.S.-born elderly people and elderly immigrants to the United States have a significantly…

  4. Effect of liquid-polish coating on in vivo biofilm accumulation on provisional restorations: part 1.

    Science.gov (United States)

    Perez Davidi, Michael; Beyth, Nurit; Sterer, Nir; Feuerstein, Osnot; Weiss, Ervin I

    2007-01-01

    Biofilm accumulation on provisional restorations may affect the surrounding tissues' integrity. The purpose of this study was to test in vivo biofilm formation on polymethyl methacrylate (PMMA) self-cured acrylic resin provisional crowns. Three types of PMMA surfaces were tested: (1) polished, (2) polished and coated with bonding agent, and (3) polished and coated with light-cured liquid polish. After 12 hours in the oral cavity, the crown was removed and examined by confocal laser scanning microscope (CLSM) and scanning electron microscope (SEM). Biofilm, 250 Mum thick, was observed with CLSM on the polished acrylic surface. Significantly less bacterial accumulation was observed on the crowns coated with bonding agent, whereas no biofilm was observed on the crowns coated with liquid polish (P provisional restorations.

  5. Stem subsidence of polished and rough double-taper stems

    Science.gov (United States)

    Yamada, Kengo; Hirosaki, Kenichi; Takano, Masahiro; Matsumoto, Tadami

    2009-01-01

    Background and purpose Many clinical reports have indicated that polished hip stems show better clinical results than rough stems of the same geometry. It is still unknown, however, what the mechanical effects are of different surface finishes on the cement at the cement-bone interface. We compared mechanical effects in an in vitro cemented hip arthroplasty model. Methods Two sizes of double-taper polished stems and matt-processed polished stems (rough stems) were fixed into composite femurs. A 1-Hz dynamic load was applied to the stems for 1 million cycles. An 8-h no-load period was set after every 16 h of load. Stem subsidence within the cement, and compressive force and horizontal cement creep at the cement-bone interface, were measured. Results Compared to rough stems, stem subsidence, compressive force and cement creep for polished stems were a maximum of 4, 12, and 7-fold greater, respectively. There was a strong positive correlation between stem subsidence and compressive force for polished stems. In contrast, a strong negative correlation was found between stem subsidence and compressive force for rough stems. There was also a statistically significant relationship between compressive force on the cement and cement creep for the polished stems, but no significant relationship was found for rough stems. Interpretation This is the first evidence that different surface finishes of stems can have different mechanical effects on the cement at the cement-bone interface. Stem subsidence in polished stems resulted in compressive force on the cement and cement creep. The mechanical effects that polished taper stems impart on cement at the cement-bone interface probably contribute to their good long-term fixation and excellent clinical outcome. PMID:19421909

  6. Evaluation of the surface hardness of composite resins before and after polishing at different times Avaliação da dureza superficial de resinas compostas antes e após o polimento em diferentes tempos

    Directory of Open Access Journals (Sweden)

    Michelle Alexandra Chinelatti

    2006-06-01

    Full Text Available PURPOSE: The aim of this study was to evaluate the surface hardness of six composite resins: Revolution, Natural Flow, Fill Magic Flow, Flow-it! (flowables, Silux Plus (microfilled and Z100 (minifilled before and after polishing at different times. MATERIALS AND METHODS: For this purpose, 240 specimens (5mm diameter, 1.4mm high were prepared. Vickers hardness was determined before and after polishing at different times: immediately, 24h, 7 and 21 days after preparation of the samples. Statistical analysis was performed by ANOVA and Tukey test. RESULTS: There was no difference in the hardness of flowable resins, which had lower hardness than the minifilled resin. The minifilled resin showed the highest surface hardness as compared to the other materials (pPROPOSIÇÃO: O objetivo deste estudo foi avaliar a dureza superficial de seis resinas compostas - Revolution, Natural Flow, Fill Magic Flow, Flow-it! (flowables, Silux Plus (micropartículas e Z100 (híbrida - antes e após o polimento realizado em diferentes tempos. MATERIAL E MÉTODO: Foram confeccionados 240 corpos-de-prova circulares (5mm de diâmetro e 1,4mm de altura. A dureza Vickers foi obtida antes e após o polimento realizado em diferentes tempos: imediatamente, 24 horas, 7 dias e 21 dias após a confecção do corpo-de-prova. Os dados foram analisados estatisticamente por meio da ANOVA e do Teste de Tukey. RESULTADOS: Não houve diferença entre as resinas compostas flowable, as quais apresentaram os menores valores de dureza. A resina composta híbrida demonstrou os melhores resultados. Todos os materiais exibiram aumento de dureza após a realização do polimento, que foi mais evidente após 7 dias. CONCLUSÃO: Pôde-se concluir que, independente do tipo de resina composta, a dureza superficial foi consideravelmente maior quando o polimento foi realizado 1 semana após a confecção dos corpos-de-prova.

  7. Extraction of molybdenum VI by alpha benzoinoxime

    International Nuclear Information System (INIS)

    Achache, M.; Meklati, M.

    1990-06-01

    The concentration of molybdenum, was studied using alpha benzoinoxime dissolved in chloroform. Several acids and salt at different levels of concentration were investigated as well as other parameters such as (mixing time, extractant to metal ratio, temperature etc.) The molybdenum stippling was also studied in alkaline medium with the subsequent recovery of the extractant and solvent

  8. Process for Functionalizing Biomass using Molybdenum Catalysts

    DEFF Research Database (Denmark)

    2015-01-01

    The present invention concerns a process for converting biomass into useful organic building blocks for the chemical industry. The process involves the use of molybdenum catalysts of the formula Aa+a(MovXxR1yR2zR3e)a*3-, which may be readily prepared from industrial molybdenum compounds....

  9. Adsorption of heavy metal ions on molybdenum and molybdenum trioxide from dilute aqueous solution

    International Nuclear Information System (INIS)

    Utsunomiya, Taizo; Hoshino, Yoshio; Sakabe, Ken-ichi

    1984-01-01

    The adsorption of heavy metal ions such as Co(II), Cu(II) and Pb(II) on molybdenum powder has been investigated by the batch technique as a function of soaking time, concentration of heavy metal ions and coexisting salts, pH etc. Molybdenum trioxide was also used as an adsorbent for a comparison to discuss the adsorption mechanism. The amount of these heavy metal ions adsorbed was highly pH and coexisting salts dependent. These adsorbents have features of selective adsorption for Pb(II) and large adsorption rate. The adsorption of heavy metal ions on these adsorbents proceeds independently or concurrently by following complex mechanism; (1) cation exchange reaction by hydroxyl radical on the surface of Mo and MoO 3 is predominant for most of heavy metal ions except Pb(II) [Co(II), Mn(II), Fe(III), Ni(II), Zn(II), Cd(II) and Sr(II)], (2) reduction (electron exchange reaction) to low ionic or metallic state after cation exchange reaction [Cu(II) and Ag(I) on Mo] and (3) formation of a compound [Pb(II) on both Mo and MoO 3 ]. (author)

  10. Uranium in the Bunter sediments of the Polish area

    International Nuclear Information System (INIS)

    Saldan, M.; Strzelecki, R.

    1980-01-01

    Uranium mineralization occurring in the Triassic sediments in the Polish area is discussed. Systematic work conducted for over ten years revealed the presence of uranium mineralization in the following geological units: Peribaltic syneclize, Fore-Sudetic monocline, Zary pericline and Pomerania trough. Out of three uranium-bearing horizons which can be correlated with each other two (the lower and the middle) are connected with the Middle Bunter, while the upper horizon is related to the Upper Bunter. Mineralization was found in sandstones, conglomerates, mudstones and claystones and, in the Fore-Sudetic monocline, also in carbonates. Among uranium minerals uranium black and coffinite were identified. In addition to uranium, increased vanadium, selenium and molybdenum contents were found in the sandstones. Some of the uranium-bearing horizons are of economic value. (author)

  11. In situ hydrogenation of molybdenum oxide nanowires for enhanced supercapacitors

    KAUST Repository

    Shakir, Imran

    2014-01-01

    In situ hydrogenation of orthorhombic molybdenum trioxide (α-MoO 3) nanowires has been achieved on a large scale by introducing alcohol during the hydrothermal synthesis for electrochemical energy storage supercapacitor devices. The hydrogenated molybdenum trioxide (H xMoO3) nanowires yield a specific capacitance of 168 F g-1 at 0.5 A g-1 and maintain 108 F g-1 at 10 A g-1, which is 36-fold higher than the capacitance obtained from pristine MoO3 nanowires at the same conditions. The electrochemical devices made with HxMoO3 nanowires exhibit excellent cycling stability by retaining 97% of their capacitance after 3000 cycles due to an enhanced electronic conductivity and increased density of hydroxyl groups on the surface of the MoO3 nanowires. This journal is © The Royal Society of Chemistry.

  12. Chemical mechanical polishing (CMP) of sapphire

    Science.gov (United States)

    Zhu, Honglin

    The concept of chemical mechanical polishing (CMP) was examined for finishing sapphire. In this study sapphire was used as a model system for oxide ceramics. The removal rates were determined by weight loss. Surface quality and structure were characterized with surface probe microscopy (SPM). Polishing experiments were designed to test the chemically modified surface layer. A series of abrasives with various hardnesses including mono-crystalline and polycrystalline diamond, alpha and gamma alumina, zirconia, ceria and silica were used. Diaspore was also evaluated. The results indicated that, with similar particle size and shape, harder abrasives do not necessarily cause faster material removal and better surface finish, and abrasives with hardness equal to or less than sapphire such as alpha alumina and gamma alumina achieved the best surface finish and efficient material removal. A hypothesis was proposed that the sapphire surface was modified by water to form a thin hydration laver with structure and hardness close to diaspore. Abrasives with a hardness between diaspore and sapphire polished the c-plane of sapphire with good surface finish and efficient removal. SPM indicated the hydration layer on the c-plane surface was about 1 nm thick. Removal rate and surface finish as a function of pH were also examined on c-plane sapphire with nano-alumina abrasives. The removal rate as a function of pH was compared to the solubility behavior of alumina. The results showed the deviation of pH from the lowest solubility pH for alumina (pH = 5) was a driving force for the surface reaction to form a hydration layer. The anisotropy of sapphire strongly affects removal rate and surface quality in CMP. The relationships among orientation. pH and abrasive were studied for sapphire with c (0001), a (11-20), and m (10-10) planes. Based on the results, the CMP process for sapphire includes chemical reaction of the surface to form a thin reaction layer that is softer than sapphire

  13. Superficial roughness on composite surface, composite enamel and composite dentin junctions after different finishing and polishing procedures. Part I: roughness after treatments with tungsten carbide vs diamond burs.

    Science.gov (United States)

    Ferraris, Federico; Conti, Alessandro

    2014-01-01

    The aim of this study is to investigate different instruments for finishing composite restorations, as well as examining different surfaces and interfaces of the same restoration. The null hypothesis is represented by the fact that there are no significant differences on roughness of composite restorations finishing between tungsten carbide and diamond burs, furthermore the null hypothesis is that there are no significant differences on roughness between finishing on composite surfaces (C), compositeenamel (CE) and composite-dentin (CD) interfaces. The study was performed on 28 teeth, and class V cavities were prepared on the extracted teeth. Restorations were done in Filtek XTE nanofilled composite (3M Espe) in a standardized method, to then be finished. A comparison was made in the phase 1 between tungsten carbide burs (16 blades), diamond burs (46 μm), with a similar shape by the same manufacturer (Komet). Each surface received 5 bur applications. Consequently, an analysis with a profilometer was performed. Phase 2 involved further confrontation of ulterior finishing with ultrafine tungsten carbide burs (30 blades) and with extra and ultrafine diamond burs (25 and 8 μm) (the same shape as previously mentioned). A second analysis was then performed with a profilometer. All measurements were taken on C surfaces, CE and CD interfaces. Statistical analyses were carried out with c2 test (a = 0.05). The finishing procedures with fine grit or toothing burs gave a better smoothness with tungsten carbide burs compared to diamond burs. While with the ultrafine grit no significant differences were noted between tungsten carbide and diamond burs on the CE and CD interfaces, the diamond bur left less superficial roughness on the C surfaces. With regards to the superficial roughness of the different areas of restoration, it can be concluded that: minor roughness was detected on C surfaces, while the CD interface had the most superficial roughness, regardless of whether the

  14. Determination of molybdenum (VI) in sea water with preliminary concentration by the method of ion flotation

    International Nuclear Information System (INIS)

    Andreeva, I. Yu.; Drapchinskaya, O.L.; Lebedeva, L.I.

    1985-01-01

    The purpose of this paper is to assess the feasibility of using the method of ion flotation for the concentration of microamounts of molybdenum (VI) during determination in sea water. The ion flotation method is used for the purification of industrial sewage from the ions of nonferrous metals, including molybdenum (VI) with its content of up to 50 mg/liter. A 1.10 -4 M solution of sodium molybdate in 0.1M NaOH was used. The effect of different factors on the ion flotation process of molybdenum (VI) was investigated: pH of the solution, flotation times, concentrations of surface-active substances (SAS), molybdenum (IV), extraneous salts. Data presented show that the ion flotation method in conjunction with the photometric method of determining molybdenum with brompyrogallol red (BPR) and cetylpridinium chloride (CP) (limit of detection 0.02 micrograms/liter) allows the content of molybdenum (VI) in sea water to be established with sufficient reliability and reproducibility

  15. Magnetic composites based on metallic nickel and molybdenum carbide: A potential material for pollutants removal

    Energy Technology Data Exchange (ETDEWEB)

    Mambrini, Raquel V.; Fonseca, Thales L. [Departamento de Quimica, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901 (Brazil); Dias, Anderson [Departamento de Quimica, Universidade Federal de Ouro Preto, Ouro Preto, MG 35400-000 (Brazil); Oliveira, Luiz C.A.; Araujo, Maria Helena [Departamento de Quimica, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901 (Brazil); Moura, Flavia C.C., E-mail: flaviamoura@ufmg.br [Departamento de Quimica, Universidade Federal de Minas Gerais, Belo Horizonte, MG 31270-901 (Brazil)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer New magnetic molybdenum carbide composites can be prepared by CVD from ethanol. Black-Right-Pointing-Pointer Magnetic molybdenum carbide shows promising results for pollutants removal. Black-Right-Pointing-Pointer The carbide composites can be easily recovered magnetically and reused. - Abstract: New magnetic composites based on metallic nickel and molybdenum carbide, Ni/Mo{sub 2}C, have been produced via catalytic chemical vapor deposition from ethanol. Scanning electron microscopy, thermal analysis, Raman spectroscopy and X-ray diffraction studies suggest that the CVD process occurs in a single step. This process involves the reduction of NiMo oxides at different temperatures (700, 800 and 900 Degree-Sign C) with catalytic deposition of carbon from ethanol producing molybdenum carbide on Ni surface. In the absence of molybdenum the formation of Ni/C was observed. The magnetic molybdenum carbide was successfully used as pollutants removal by adsorption of sulfur and nitrogen compounds from liquid fuels and model dyes such as methylene blue and indigo carmine. The dibenzothiofene adsorption process over Ni/Mo{sub 2}C reached approximately 20 mg g{sup -1}, notably higher than other materials described in the literature and also removed almost all methylene blue dye. The great advantage of these carbide composites is that they may be easily recovered magnetically and reused.

  16. Magnetic composites based on metallic nickel and molybdenum carbide: A potential material for pollutants removal

    International Nuclear Information System (INIS)

    Mambrini, Raquel V.; Fonseca, Thales L.; Dias, Anderson; Oliveira, Luiz C.A.; Araujo, Maria Helena; Moura, Flávia C.C.

    2012-01-01

    Highlights: ► New magnetic molybdenum carbide composites can be prepared by CVD from ethanol. ► Magnetic molybdenum carbide shows promising results for pollutants removal. ► The carbide composites can be easily recovered magnetically and reused. - Abstract: New magnetic composites based on metallic nickel and molybdenum carbide, Ni/Mo 2 C, have been produced via catalytic chemical vapor deposition from ethanol. Scanning electron microscopy, thermal analysis, Raman spectroscopy and X-ray diffraction studies suggest that the CVD process occurs in a single step. This process involves the reduction of NiMo oxides at different temperatures (700, 800 and 900 °C) with catalytic deposition of carbon from ethanol producing molybdenum carbide on Ni surface. In the absence of molybdenum the formation of Ni/C was observed. The magnetic molybdenum carbide was successfully used as pollutants removal by adsorption of sulfur and nitrogen compounds from liquid fuels and model dyes such as methylene blue and indigo carmine. The dibenzothiofene adsorption process over Ni/Mo 2 C reached approximately 20 mg g −1 , notably higher than other materials described in the literature and also removed almost all methylene blue dye. The great advantage of these carbide composites is that they may be easily recovered magnetically and reused.

  17. Atomic physics for fusion plasma spectroscopy; a soft x-ray study of molybdenum ions

    International Nuclear Information System (INIS)

    Fournier, K.B.

    1996-01-01

    Understanding the radiative patterns of the ions of heavy atoms (Z approx-gt 18) is crucial to fusion experiments. The present thesis applies ab initio, relativistic calculations of atomic data to modeling the emission of molybdenum (Z = 42) ions in magnetically confined fusion plasmas. The models are compared to observations made in the Alcator C-Mod tokamak (Plasma Fusion Center, Massachusetts Institute of Technology), and the Frascati Tokamak Upgrade. Experimental confirmation of these models allows confidence in calculations of the total molybdenum concentration and quantitative estimates of the total power lost from the plasmas due to molybdenum line radiation. Charge states in the plasma core (Mo 33+ to Mo 29+ ) emit strong x-ray and XUV spectra which allow benchmarking of models for the spatial distribution of highly stripped molybdenum ions; the models only achieve agreement with observations when the rates of indirect ionization and recombination processes are included in the calculation of the charge state distribution of the central molybdenum ions. The total concentration of molybdenum in the core of the plasma is found, and the total power radiated from the plasma core is computed. Observations of line emission from more highly charged molybdenum ions (Mo 36+ to Mo 34+ ) are presented. open-quotes Bulkclose quotes molybdenum charge states (Mo 25+ to Mo 23+ ) emit complicated XUV spectra from a position in the plasma near C-Mod's half radius; spatial profiles of these ions' emission are analyzed. Models for the line-emission spectra of adjacent ions (Mo 28+ to Mo 26+ ) are offered, and the accuracy and limits of ab initio energy level calculations are discussed. open-quotes Edgeclose quotes charge states (Mo 22+ to Mo 15 ) extend to the last closed magnetic flux surface of the C-Mod plasma. The strongest features from these charge states are emitted in a narrow band from ∼70 Angstrom

  18. Polishing of Monolithic Zirconia Crowns—Results of Different Dental Practitioner Groups

    Directory of Open Access Journals (Sweden)

    Carla Kozmacs

    2017-11-01

    Full Text Available This pilot study evaluates the surface roughness of monolithic zirconia crowns after chairside polishing by different dental practitioner groups. Four practitioner groups (group I: dental clinical students (n = 6; group II: dentists < 2 years post-qualification experience (n = 6; group III: dentists > 2 years post-qualification experience (n = 6 and group IV: dental technicians (n = 6 were asked to polish two CAD/CAM-fabricated full-contour zirconia crowns (48 in total. A two-step zirconia polishing kit was used in both trials. The first trial (T1 was conducted without a time limitation. In the second trial (T2, the polish was restricted to 15 seconds for each polisher. Two blinded investigators (I1 and I2 analyzed the surface roughness (Ra before and after polishing (Alicona measuring system. No statistically significant difference in surface roughness was found between the polishing results of the dental practitioner groups. Major difference in surface finish was achieved by dental technicians, with a median value of 25.4 nm (interquartile range 10.15–35.26 nm for I1 in T1. The lowest difference was achieved by dental students, with a median value of Ra = 6.72 nm (interquartile range 4.7–17.9 nm in T1. In T2, experienced dentists showed the highest difference in surface finish, with a median value of 41.35 nm (interquartile range 7.77–54.11. No significant correlation was found between polishing time and polishing results. The polishing of monolithic zirconium dioxide crowns can be performed with the present polishing set directly chairside after occlusal adjustment, regardless of the practitioner’s experience level.

  19. Polishing of Monolithic Zirconia Crowns-Results of Different Dental Practitioner Groups.

    Science.gov (United States)

    Kozmacs, Carla; Hollmann, Britta; Arnold, Wolfgang H; Naumova, Ella; Piwowarczyk, Andree

    2017-11-14

    This pilot study evaluates the surface roughness of monolithic zirconia crowns after chairside polishing by different dental practitioner groups. Four practitioner groups (group I: dental clinical students ( n = 6); group II: dentists 2 years post-qualification experience ( n = 6) and group IV: dental technicians ( n = 6)) were asked to polish two CAD/CAM-fabricated full-contour zirconia crowns (48 in total). A two-step zirconia polishing kit was used in both trials. The first trial (T1) was conducted without a time limitation. In the second trial (T2), the polish was restricted to 15 seconds for each polisher. Two blinded investigators (I1 and I2) analyzed the surface roughness (Ra) before and after polishing (Alicona measuring system). No statistically significant difference in surface roughness was found between the polishing results of the dental practitioner groups. Major difference in surface finish was achieved by dental technicians, with a median value of 25.4 nm (interquartile range 10.15-35.26 nm) for I1 in T1. The lowest difference was achieved by dental students, with a median value of Ra = 6.72 nm (interquartile range 4.7-17.9 nm) in T1. In T2, experienced dentists showed the highest difference in surface finish, with a median value of 41.35 nm (interquartile range 7.77-54.11). No significant correlation was found between polishing time and polishing results. The polishing of monolithic zirconium dioxide crowns can be performed with the present polishing set directly chairside after occlusal adjustment, regardless of the practitioner's experience level.

  20. Tooth polishing: The current status

    Directory of Open Access Journals (Sweden)

    Madhuri Alankar Sawai

    2015-01-01

    Full Text Available Healthy teeth and gums make a person feel confident and fit. As people go about their daily routines and with different eating and drinking habits, the tooth enamel turns yellowish or gets stained. Polishing traditionally has been associated with the prophylaxis procedure in most dental practices, which patients know and expect. However, with overzealous use of polishing procedure, there is wearing of the superficial tooth structure. This would lead to more accumulation of local deposits. Also, it takes a long time for the formation of the fluoride-rich layer of the tooth again. Hence, now-a-days, polishing is not advised as a part of routine oral prophylaxis procedure but is done selectively based on the patients′ need. The article here, gives an insight on the different aspects of the polishing process along with the different methods and agents used for the same.

  1. Lysenko affair and Polish botany.

    Science.gov (United States)

    Köhler, Piotr

    2011-01-01

    This article describes the slight impact of Lysenkoism upon Polish botany. I begin with an account of the development of plant genetics in Poland, as well as the attitude of scientists and the Polish intelligentsia toward Marxist philosophy prior to the World War II. Next I provide a short history of the introduction and demise of Lysenkoism in Polish science, with a focus on events in botany, in context with key events in Polish science from 1939 to 1958. The article outlines the little effects of Lysenkoism upon botanists and their research, as well as how botanists for the most part rejected what was often termed the "new biology." My paper shows that though Lysenko's theories received political support, and were actively promoted by a small circle of scientists and Communist party activists, they were never accepted by most botanists. Once the political climate in Poland altered after the events of 1956, Lysenko's theories were immediately abandoned.

  2. Deposition and Characterization of Molybdenum Thin Film Using Direct Current Magnetron and Atomic Force Microscopy

    Directory of Open Access Journals (Sweden)

    Muhtade Mustafa Aqil

    2017-01-01

    Full Text Available In this paper, pure molybdenum (Mo thin film has been deposited on blank Si substrate by DC magnetron sputtering technique. The deposition condition for all samples has not been changed except for the deposition time in order to study the influence of time on the thickness and surface morphology of molybdenum thin film. The surface profiler has been used to measure the surface thickness. Atomic force microscopy technique was employed to investigate the roughness and grain structure of Mo thin film. The thickness and grain of molybdenum thin film layer has been found to increase with respect to time, while the surface roughness decreases. The average roughness, root mean square roughness, surface skewness, and surface kurtosis parameters are used to analyze the surface morphology of Mo thin film. Smooth surface has been observed. From grain analysis, a uniform grain distribution along the surface has been found. The obtained results allowed us to decide the optimal time to deposit molybdenum thin film layer of 20–100 nm thickness and subsequently patterned as electrodes (source/drain in carbon nanotube-channel transistor.

  3. The Application of Gravity and CSAMT Survey on Baishan Molybdenum Deposit, Hami, Xinjiang,China

    Science.gov (United States)

    Yang, Y.; Lu, H.; Zhang, K.

    2014-12-01

    Baishan molybdenum deposit is located in the eastern Tianshan Carboniferous rift at Hami, Xinjiang, China, where exposed upper Carboniferous Gandun formation. Molybdenum ore appeared at thermal contact metamorphism hornfelsed banded quartz stockwork in the concealed porphyritic granite top, Potassium and metal sulfide mineralization existed in the top of concealed rockbody.The Baishan molybdenum ore bodies were delineated 2700 meters long and 40 meters thickness, with molybdenum @ 0.59%. The main orebody shows in stratoid, small orebody appears in lenticular and vein.In order to predict potential resources, we proposes a combined method of CSAMT and GS technology,and has applied it to the survey of concealed molybdenum deposit in the Baishan.This combind method can explore to larger depths, discriminate anomalies well and has higher resolution to deep objects, thus it is an efficient tool for surveys.By drilling, we found there exsit a hidden granite body in 1400 meters deep of Hami Baishan molybdenum mine, it confirmed that Baishan molybdenum mine is a porphyry molybdenum ore. Cataclastic hornfelsed zone in the coping granite are the product of heat contact metamorphism, the ore materials are mainly derived from deep magma hydrothermal solution. The CSAMT and Gravity Survey were able to reflect the space and intrusive boundary in rough of buried granite body clearly, deep hidden granite showed high-resistivity and high-gravity anomaly and the low-resistivity anomaly distributied around them, drilling verified that 200-2500Ω low-resistivity anomaly range at top of high-resistivity corresponded to the molybdenum ore horizon. Line 15 of southern section shows two low resistance anomaly zone, and the surface of them is corresponding to the granite and intrusive contact parts,inferring it was caused by the fault structure.In granite gravity anomaly is obviously high and the width is about 560m,Δg residual value is 400 × 10-8m/s2. According to the control of

  4. Development of Chemosorbent Based on Metallic Waste for Cleaning Mine Water From Molybdenum

    Directory of Open Access Journals (Sweden)

    Alexander Evgenyevich Isakov

    2018-01-01

    Full Text Available The article presents the results of hydrochemical studies of water objects, located in the impact zone of one of the largest mining enterprises in the Russian Federation – JSC “Apatite”. According to the monitoring studies, the source of surface water pollution with molybdenum was determined, geochemical assessment of the molybdenum transformation in the system “ore-bearing rocks – mine water – surface water” was performed. In order to reduce the technogenic load on the surface water located in the considered area, the way of large-tonnage mine waters purificationfrom molybdenum was proposed. The method involves using the chemical sorbent based on waste metals. The method of sewage purificationwill allow solving one of the key environmental problems of the considered enterprise and, in addition, to improve the environmental situation in the considered area as well as the quality of the local population life.

  5. THE POLISH RECIPE

    Directory of Open Access Journals (Sweden)

    D.F. Spinu

    2017-06-01

    Full Text Available Twenty-six years ago the international community witnessed one of the most dramatic changes in economic systems. Naturally, the fall of communism in Eastern Europe and its consequences were events difficult to judge and anticipate in their immediate aftermath. Today, we have gained a much more coherent perspective on their meaning. The political liberalization of Poland in 1989 and its transition to the market economy was generally perceived as the most successful of all post-communist countries. From 1990 to 2013, Poland experienced the most outstanding economic growth within the former communist bloc. It doubled its GDP in real terms and became the only country to experience economic growth during the financial crisis of 2008-09. However, the polish secret recipe lies in the "shock therapy" adopted at the beginning of the 90's. The aim of this paper is to examine the importance of the Balcerowicz's program in creating the basis for economic stability and growth through privatization, liberalization of foreign trade, monetary reform and an open economy. We will also review the impact of this unprecedented transformation in shaping a strong, market-oriented economy.

  6. Applicability of chemical vapour polishing of additive manufactured parts to meet production-quality

    DEFF Research Database (Denmark)

    Pedersen, D. B.; Hansen, H. N.; Nielsen, J. S.

    2014-01-01

    The Fused Deposition Modelling (FDM) method is the most rapidly growing Additive Manufacturing (AM) method[1]. FDM employs a 2.5D deposition scheme which induce a step-ladder shaped surface definition [2], with seams of the individual layers clearly visible[3]. This paper investigate to which...... extend chemical vapour polishing can be applied to eliminate the layered surfaces from FDM, so that a polished surface quality is obtained. It is quantified to what extend parts can be vapour polished and how geometrical and mechanical properties alter. The fundamental question is whether the surfaces...... of FDM manufactured parts can be taken from their current quality into the precision engineering domain....

  7. Laser polishing of 3D printed mesoscale components

    Science.gov (United States)

    Bhaduri, Debajyoti; Penchev, Pavel; Batal, Afif; Dimov, Stefan; Soo, Sein Leung; Sten, Stella; Harrysson, Urban; Zhang, Zhenxue; Dong, Hanshan

    2017-05-01

    Laser polishing of various engineered materials such as glass, silica, steel, nickel and titanium alloys, has attracted considerable interest in the last 20 years due to its superior flexibility, operating speed and capability for localised surface treatment compared to conventional mechanical based methods. The paper initially reports results from process optimisation experiments aimed at investigating the influence of laser fluence and pulse overlap parameters on resulting workpiece surface roughness following laser polishing of planar 3D printed stainless steel (SS316L) specimens. A maximum reduction in roughness of over 94% (from ∼3.8 to ∼0.2 μm Sa) was achieved at the optimised settings (fluence of 9 J/cm2 and overlap factors of 95% and 88-91% along beam scanning and step-over directions respectively). Subsequent analysis using both X-ray photoelectron spectroscopy (XPS) and glow discharge optical emission spectroscopy (GDOES) confirmed the presence of surface oxide layers (predominantly consisting of Fe and Cr phases) up to a depth of ∼0.5 μm when laser polishing was performed under normal atmospheric conditions. Conversely, formation of oxide layers was negligible when operating in an inert argon gas environment. The microhardness of the polished specimens was primarily influenced by the input thermal energy, with greater sub-surface hardness (up to ∼60%) recorded in the samples processed with higher energy density. Additionally, all of the polished surfaces were free of the scratch marks, pits, holes, lumps and irregularities that were prevalent on the as-received stainless steel samples. The optimised laser polishing technology was consequently implemented for serial finishing of structured 3D printed mesoscale SS316L components. This led to substantial reductions in areal Sa and St parameters by 75% (0.489-0.126 μm) and 90% (17.71-1.21 μm) respectively, without compromising the geometrical accuracy of the native 3D printed samples.

  8. molybdenum

    African Journals Online (AJOL)

    A [13]). However, the larger size leads to an enhanced Si-C bond length (1.868 A [13]) relative to that of the C-C bond (1.527 Á [13]). This leads to a net cancellation of effects. Consequently the data suggest that the SiMe, and 'Bu appear of similar size when viewed from the centroid of the substituted cyclopentadienyl ligand ...

  9. Polished Stone Value Test and its relationship with petrographic parameters (hardness contrast and modal composition and surface micro-roughness in natural and artificial aggregates

    Directory of Open Access Journals (Sweden)

    Fernández, A.

    2013-09-01

    Full Text Available The goal of this work was first to establish the relationships between the PSV values and the microstructural and mineralogical features of the aggregates and surface micro-roughness, and then to establish the behavioural differences between natural and artificial aggregates. The results obtained indicate that the surface micro-roughness and the different PSV values of the natural aggregates are strongly governed by the existence of minerals with different degrees of hardness, together with the proportion of these minerals. In contrast, the different degree of porosity in artificial aggregates (a furnace slag was seen to be responsible for its high surface micro-roughness and PSV values. Finally, the PSV and a petrographic parameter (Overall Hardness Contrast, ΔH were seen to be related by an exponential curve (PSV=39.726ΔH0.057 with an extremely good fit, providing a good tool to estimate PSVs in natural and artificial aggregates from petrographic parameters.El objetivo de este trabajo es establecer, por un lado, las relaciones existentes del CPA con las características petrográficas de los áridos, así como su microrrugosidad superficial y, por otro, las diferencias de comportamiento entre áridos naturales y artificiales. Los resultados indican que en los áridos naturales la microrrugosidad superficial y el diferente valor del CPA están determinados, en gran medida, por las diferencias de dureza de sus minerales y también por la proporción en la que estos minerales se encuentran en las distintas litologías. Sin embargo, en los áridos artificiales (escorias de fundición su elevada porosidad es la responsable de su marcada microrrugosidad superficial y su elevado valor del CPA. Finalmente, se relaciona el CPA con un parámetro petrográfico (Contraste de Dureza Global, ΔH mediante una curva exponencial, cuyo excelente índice de regresión hace que sea factible estimar mediante el estudio petrográfico de un árido su valor del CPA

  10. Polish Toxic Currency Options

    Directory of Open Access Journals (Sweden)

    Waldemar Gontarski

    2009-04-01

    Full Text Available Toxic currency options are defined on the basis of the opposition to the nature (essence of an option contract, which is justified in terms of norms founded on the general law clause of characteristics (nature of a relation (which represents an independent premise for imposing restrictions on the freedom of contracts. So-understood toxic currency options are unlawful. Indeed they contravene iuris cogentis regulations. These include for instance option contracts, which are concluded with a bank, if the bank has not informed about option risk before concluding the contract; or the barrier options, which focus only on the protection of banks interests. Therefore, such options may appear to be invalid. Therefore, performing contracts for toxic currency options may be qualified as a criminal mismanagement. For the sake of security, the manager should then take into consideration filing a claim for stating invalidity (which can be made in a court verdict. At the same time, if the supervisory board member in a commercial company, who can also be a subject to mismanagement offences, commits an omission involving lack of reaction (for example, if he/she fails to notify of the suspected offence committed by the management board members acting to the companys detriment when the management board makes the company conclude option contracts which are charged with absolute invalidity the supervisory board member so acting may be considered to act to the companys detriment. In the most recent Polish jurisprudence and judicature the standard of a good host is treated to be the last resort for determining whether the managers powers resulting from criminal regulations were performed. The manager of the exporter should not, as a rule, issue any options. Issuing options always means assuming an obligation. In the case of currency put options it is an absolute obligation to purchase a given amount in euro at exchange rate set in advance. On the other hand issuing

  11. Robotic Automation in Computer Controlled Polishing

    Science.gov (United States)

    Walker, D. D.; Yu, G.; Bibby, M.; Dunn, C.; Li, H.; Wu, Y.; Zheng, X.; Zhang, P.

    2016-02-01

    We first present a Case Study - the manufacture of 1.4 m prototype mirror-segments for the European Extremely Large Telescope, undertaken by the National Facility for Ultra Precision Surfaces, at the OpTIC facility operated by Glyndwr University. Scale-up to serial-manufacture demands delivery of a 1.4 m off-axis aspheric hexagonal segment with surface precision use of robots to automate currently-manual operations on CNC polishing machines, to improve work-throughput, mitigate risk of damage to parts, and reduce dependence on highly-skilled staff. Second is the use of robots to pre-process surfaces prior to CNC polishing, to reduce total process time. The third draws the threads together, describing our vision of the automated manufacturing cell, where the operator interacts at cell rather than machine level. This promises to deliver a step-change in end-to-end manufacturing times and costs, compared with either platform used on its own or, indeed, the state-of-the-art used elsewhere.

  12. Comparison of Heavy-Duty Scuffing Behavior between Chromium-Based Ceramic Composite and Nickel-Chromium-Molybdenum-Coated Ring Sliding against Cast Iron Liner under Starvation.

    Science.gov (United States)

    Shen, Yan; Yu, Baihong; Lv, Yutao; Li, Bin

    2017-10-14

    A running-in and starved lubrication experiment is designed to investigate the heavy-duty scuffing behavior of piston ring coatings against cast iron (Fe) cylinder liner using the piston ring reciprocating liner test rig. The scuffing resistance of the piston ring with the chromium-based ceramic composite coating (CKS), and that with the thermally sprayed nickel-chromium-molybdenum coating (NCM) is compared at different nominal pressures (40~100 MPa) and temperatures (180~250 °C). With the failure time as a criterion, the rank order is as follows: NCM/Fe > CKS/Fe. Before the scoring occurs at the interface of the piston ring and cylinder liner (PRCL), the cast iron liner enters into a "polish wear" stage, and iron-based adhesive materials begin to form on the piston ring surface. With the macroscopic adhesion formation, the plastic shearing cycle causes surface damages mainly due to abrasive effects for the CKS/Fe pairs and adhesive effects for the NCM/Fe pairs.

  13. Comparison of Heavy-Duty Scuffing Behavior between Chromium-Based Ceramic Composite and Nickel-Chromium-Molybdenum-Coated Ring Sliding against Cast Iron Liner under Starvation

    Directory of Open Access Journals (Sweden)

    Yan Shen

    2017-10-01

    Full Text Available A running-in and starved lubrication experiment is designed to investigate the heavy-duty scuffing behavior of piston ring coatings against cast iron (Fe cylinder liner using the piston ring reciprocating liner test rig. The scuffing resistance of the piston ring with the chromium-based ceramic composite coating (CKS, and that with the thermally sprayed nickel-chromium-molybdenum coating (NCM is compared at different nominal pressures (40~100 MPa and temperatures (180~250 °C. With the failure time as a criterion, the rank order is as follows: NCM/Fe > CKS/Fe. Before the scoring occurs at the interface of the piston ring and cylinder liner (PRCL, the cast iron liner enters into a “polish wear” stage, and iron-based adhesive materials begin to form on the piston ring surface. With the macroscopic adhesion formation, the plastic shearing cycle causes surface damages mainly due to abrasive effects for the CKS/Fe pairs and adhesive effects for the NCM/Fe pairs.

  14. Features of soldering of molybdenum a lols

    International Nuclear Information System (INIS)

    Grishin, V.L.; Rybkin, B.V.; Cherkasov, A.F.

    1980-01-01

    Soldering features of complex-alloy molybdenum alloys were investigated in comparison with alloys based on solid solutions. Soldering features of heterogeneous molybdenum base alloys were investigated using samples of 0.5-1.O mm sheets with the strain of about 95% made of ingots which had been smelted in arc vacuum furnaces. The soldering of samples was carried out in 5x1O -5 mm Hg vacuum using different sources of heating: radiation, electron-ray and contact. It was shown that heat-resisting soldered joints of heterogeneous molybdenum alloys could be produced using zirconium and niobium base solders containing the most effective hardeners of the parent material (titanum, vanadium, tantalum, molybdenum, tungsten). To preserve high mechanical properties of heterogeneous alloys it was expedient to use for welding local heating sources which permitted to decrease considerably temperature- time conditions of the process

  15. Large-Batch Reduction of Molybdenum Trioxide

    Energy Technology Data Exchange (ETDEWEB)

    Kiggans, Jr, James O. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Lowden, Richard Andrew [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Menchhofer, Paul A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Nunn, Stephen D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bryan, Chris [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    Unconverted, isotopically-enriched molybdenum metal must be recovered from the spent radiopharmaceutical solution used in NorthStar’s Technetium-99m generator and reused. The recycle process begins by recovering the metal from the aqueous potassium molybdate (K2MoO4) solutions as molybdenum trioxide (MoO3) employing a process developed at Argonne National Laboratory. The MoO3 powder is subsequently reduced to molybdenum metal powder which can be blended with new powder and further processed into a flowable form to be used to produce target disks for irradiation. The molybdenum oxide reduction process has been examined and scaled to produce kilogram quantities of metal powder suitable for processing into a useable form employing spray drying or similar technique and ultimately used for target fabrication.

  16. Organo molybdenum friction-reducing antiwear additives

    Energy Technology Data Exchange (ETDEWEB)

    Coupland, K.; Salva, J. M.; Smith, C. R.

    1981-02-03

    A hydrocarbon-soluble molybdenum complex consisting of a hydrocarbon substituted thio-bis-phenol, E.G. is described. The reaction product contains of 1-2 moles of nonyl phenol sulfides and one mole of molybdenum oxide (reacted if desired in the presence of an amine promoter), in combination with a sulfur donor provides lubricity activity to lubricating oils and other hydrocarbons including fuels.

  17. Elimination of excess molybdenum by cattle

    Energy Technology Data Exchange (ETDEWEB)

    Toelgyesi, G.; Elmoty, I.A.

    1967-01-01

    It was found that cattle would ingest spontaneously 5-15 g of molybdenum on one occasion. The uptake of this quantity caused but moderate loss of appetite and mild enteritis, both normalizing in one week. The occurrence of a severe acute molybdenum poisoning can be practically excluded, owing to refusal of the poisoned feed. Spontaneously ingested molybdenum caused on the first day a 30-100 fold rise of ruminal Mo-level, decreasing to the order of the normal value in about one week. But in the urine and faeces, Mo-level was at least 10 fold, in the blood and milk about 4 fold of the normal one, even one or two weeks after ingestion. During this period at least 90% of ingested Mo was eliminated with the faeces, urine and milk. One week after the ingestion of molybdenum, the rumen content showed no evidence on poisoning and no trace of molybdenum. Oral administration of ammonium molybdenate in an amount equivalent to 40 g molybdenum caused no fatality. In fact, cattle would never ingest spontaneously such a large dose.

  18. The dynamics of copper intercalated molybdenum ditelluride.

    Science.gov (United States)

    Onofrio, Nicolas; Guzman, David; Strachan, Alejandro

    2016-11-21

    Layered transition metal dichalcogenides are emerging as key materials in nanoelectronics and energy applications. Predictive models to understand their growth, thermomechanical properties, and interaction with metals are needed in order to accelerate their incorporation into commercial products. Interatomic potentials enable large-scale atomistic simulations connecting first principle methods and devices. We present a ReaxFF reactive force field to describe molybdenum ditelluride and its interactions with copper. We optimized the force field parameters to describe the energetics, atomic charges, and mechanical properties of (i) layered MoTe 2 , Mo, and Cu in various phases, (ii) the intercalation of Cu atoms and small clusters within the van der Waals gap of MoTe 2 , and (iii) bond dissociation curves. The training set consists of an extensive set of first principles calculations computed using density functional theory (DFT). We validate the force field via the prediction of the adhesion of a single layer MoTe 2 on a Cu(111) surface and find good agreement with DFT results not used in the training set. We characterized the mobility of the Cu ions intercalated into MoTe 2 under the presence of an external electric field via finite temperature molecular dynamics simulations. The results show a significant increase in drift velocity for electric fields of approximately 0.4 V/Å  and that mobility increases with Cu ion concentration.

  19. Abrasive properties of modified oxides for finish polishing of steel

    Science.gov (United States)

    Koroleva, L. F.

    2017-12-01

    The study of modified chromium and aluminum oxides, demonstrates that finish polishing by modified hydroxocomplexes based on a solid solution of iron and aluminum oxides provide a surface nanoroughness of 0.02 to 0.005 µm for the hardened ShKh15 steel (American Standard AISI 52100).

  20. Jules Verne - a new polishing technique related to FJP

    NARCIS (Netherlands)

    Booij, S.M.; Fähnle, O.W.; Meeder, M.; Wons, T.; Braat, J.J.M.

    2003-01-01

    A variation on the fluid jet polishing (FJP) technique, arbitrarily named Jules Verne (JV), will be described in this article. Jules Verne is a glass processing technique that removes material due to the fact that the tool and the surface are in close contact, and a slurry moves in between the tool

  1. Novel cavitation fluid jet polishing process based on negative pressure effects.

    Science.gov (United States)

    Chen, Fengjun; Wang, Hui; Tang, Yu; Yin, Shaohui; Huang, Shuai; Zhang, Guanghua

    2018-04-01

    Traditional abrasive fluid jet polishing (FJP) is limited by its high-pressure equipment, unstable material removal rate, and applicability to ultra-smooth surfaces because of the evident air turbulence, fluid expansion, and a large polishing spot in high-pressure FJP. This paper presents a novel cavitation fluid jet polishing (CFJP) method and process based on FJP technology. It can implement high-efficiency polishing on small-scale surfaces in a low-pressure environment. CFJP uses the purposely designed polishing equipment with a sealed chamber, which can generate a cavitation effect in negative pressure environment. Moreover, the collapse of cavitation bubbles can spray out a high-energy microjet and shock wave to enhance the material removal. Its feasibility is verified through researching the flow behavior and the cavitation results of the negative pressure cavitation machining of pure water in reversing suction flow. The mechanism is analyzed through a computational fluid dynamics simulation. Thus, its cavitation and surface removal mechanisms in the vertical CFJP and inclined CFJP are studied. A series of polishing experiments on different materials and polishing parameters are conducted to validate its polishing performance compared with FJP. The maximum removal depth increases, and surface roughness gradually decreases with increasing negative outlet pressures. The surface becomes smooth with the increase of polishing time. The experimental results confirm that the CFJP process can realize a high material removal rate and smooth surface with low energy consumption in the low-pressure environment, together with compatible surface roughness to FJP. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Tailoring molybdenum nanostructure evolution by low-energy He+ ion irradiation

    International Nuclear Information System (INIS)

    Tripathi, J.K.; Novakowski, T.J.; Hassanein, A.

    2015-01-01

    Mirror-finished polished molybdenum (Mo) samples were irradiated with 100 eV He + ions as a function of ion fluence (using a constant flux of 7.2 × 10 20 ions m −2 s −1 ) at normal incidence and at 923 K. Mo surface deterioration and nanoscopic fiber-form filament (“Mo fuzz”) growth evolution were monitored by using field emission (FE) scanning electron (SEM) and atomic force (AFM) microscopy studies. Those studies confirm a reasonably clean and flat surface, up to several micrometer scales along with a few mechanical-polishing-induced scratches. However, He + ion irradiation deteriorates the surface significantly even at 2.1 × 10 23 ions m −2 fluence (about 5 min. irradiation time) and leads to evolution of homogeneously populated ∼75-nm-long Mo nanograins having ∼8 nm intergrain width. The primary stages of Mo fuzz growth, i.e., elongated half-cylindrical ∼70 nm nanoplatelets, and encapsulated bubbles of 20–45 nm in diameter and preferably within the grain boundaries of sub-micron-sized grains, were observed after 1.3 × 10 24 ions m −2 fluence irradiation. Additionally, a sequential enhancement in the sharpness, density, and protrusions of Mo fuzz at the surface with ion fluence was also observed. Fluence- and flux-dependent studies have also been performed at 1223 K target temperature (beyond the temperature window for Mo fuzz formation). At a constant fluence of 2.6 × 10 24 ions m −2 , 7.2 × 10 20 ions m −2 s −1 flux generates a homogeneous layered and stacked nanodiscs of ∼70 nm diameter. On the other hand, 1.2 × 10 21 ions m −2 s −1 flux generates a combination of randomly patched netlike nanomatrix networked structure, mostly with ∼105 nm nanostructure wall width, various-shaped pores, and self-organized nano arrays. While the observed netlike nanomatrix network structures for 8.6 × 10 24 ions m −2 fluence (at a constant flux of 1.2 × 10 21 ions m −2 s −1 ) is quite similar to those for 2.6 × 10 24 ions m −2

  3. Tailoring molybdenum nanostructure evolution by low-energy He{sup +} ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Tripathi, J.K., E-mail: jtripat@purdue.edu; Novakowski, T.J.; Hassanein, A.

    2015-10-30

    Mirror-finished polished molybdenum (Mo) samples were irradiated with 100 eV He{sup +} ions as a function of ion fluence (using a constant flux of 7.2 × 10{sup 20} ions m{sup −2} s{sup −1}) at normal incidence and at 923 K. Mo surface deterioration and nanoscopic fiber-form filament (“Mo fuzz”) growth evolution were monitored by using field emission (FE) scanning electron (SEM) and atomic force (AFM) microscopy studies. Those studies confirm a reasonably clean and flat surface, up to several micrometer scales along with a few mechanical-polishing-induced scratches. However, He{sup +} ion irradiation deteriorates the surface significantly even at 2.1 × 10{sup 23} ions m{sup −2} fluence (about 5 min. irradiation time) and leads to evolution of homogeneously populated ∼75-nm-long Mo nanograins having ∼8 nm intergrain width. The primary stages of Mo fuzz growth, i.e., elongated half-cylindrical ∼70 nm nanoplatelets, and encapsulated bubbles of 20–45 nm in diameter and preferably within the grain boundaries of sub-micron-sized grains, were observed after 1.3 × 10{sup 24} ions m{sup −2} fluence irradiation. Additionally, a sequential enhancement in the sharpness, density, and protrusions of Mo fuzz at the surface with ion fluence was also observed. Fluence- and flux-dependent studies have also been performed at 1223 K target temperature (beyond the temperature window for Mo fuzz formation). At a constant fluence of 2.6 × 10{sup 24} ions m{sup −2}, 7.2 × 10{sup 20} ions m{sup −2} s{sup −1} flux generates a homogeneous layered and stacked nanodiscs of ∼70 nm diameter. On the other hand, 1.2 × 10{sup 21} ions m{sup −2} s{sup −1} flux generates a combination of randomly patched netlike nanomatrix networked structure, mostly with ∼105 nm nanostructure wall width, various-shaped pores, and self-organized nano arrays. While the observed netlike nanomatrix network structures for 8.6 × 10{sup 24} ions m{sup −2} fluence (at a constant

  4. Cannabinoids cases in polish athletes

    OpenAIRE

    A Pokrywka; Z Obmiński; D Kwiatkowska; R Grucza

    2009-01-01

    The aim of this study was to investigate the number of cases and the profiles of Polish athletes who had occasionally been using marijuana or hashish throughout the period of 1998-2004, with respect to: sex, age, and discipline of sport as well as the period of testing (in- and out-of-competition). Results of the study were compared with some data reported by other WADA accredited anti-doping laboratories. Totally, 13 631 urine samples taken from Polish athletes of both sexes, aged 10-67 year...

  5. Delayed polishing technique on glass–ionomer restorations

    Directory of Open Access Journals (Sweden)

    Masao Irie

    2009-05-01

    Full Text Available This in vitro study evaluated the effect of polishing after 1-day storage in water on the gap-formation around a Class V and Class I restorations, using a resin-modified glass–ionomer and a conventional glass–ionomer materials. The study also examined the gap-formation in another two different cervical restorations, a cervical cavity: incisally bordered by enamel and cervically by dentin and a root surface cavity of these restorative materials, which may be effects of this polishing procedure. This study evaluated the effects of delayed versus immediate polishing to permit maturation on: (1 interfacial gap-formation around resin-modified (RMGIC and conventional (CGIC in three types of cervical restorations, (2 interfacial gap-formation around highly viscous conventional glass–ionomer cement (HCGIC in Class I restorations. After polishing procedure, either: (i immediately (3 or 6 min after setting or (ii after 24 h storage, the maximum the restored teeth were sectioned in a mesio-distal direction through the center of the restorations. The presence or absence of interfacial-gaps was measured at 14 points (each 0.5-mm apart along the cavity restoration interface. For various restorative cases, significant differences (p < 0.05 in gap-width or gap-incidence, were observed between polishing (i immediately and (ii after 1-day storage.

  6. A novel vibration assisted polishing device based on the flexural mechanism driven by the piezoelectric actuators

    Directory of Open Access Journals (Sweden)

    Guilian Wang

    2018-01-01

    Full Text Available The vibration assisted polishing has widely application fields because of higher machining frequency and better polishing quality, especially the polishing with the non-resonant mode that is regarded as a kind of promising polishing method. This paper reports a novel vibration assisted polishing device, consisting of the flexible hinge mechanism driven by the piezoelectric actuators, which is suitable for polishing planes or curve surfaces with slow curvature. Firstly, the generation methods of vibration trajectory are investigated for the same frequency and different frequency signals’ inputs, respectively, and then the types of elliptic and Lissajous’s vibration trajectories are generated respectively. Secondly, a flexural mechanism consisting of the right circular flexible hinges and the leaf springs is developed to produce two-dimensional vibration trajectory. Statics and dynamics investigating of this flexible mechanism are finished in detail. The analytical models about input and output compliances of the flexural mechanism are established according to the matrix-based compliance modeling, and the dynamic model of the flexural mechanism based on the Euler-Lagrange equation is also presented. The finite element model of the flexural mechanism was established to carry out the numerical simulation in order to testify the rationality of device design. Finally, the polishing experiment is carried out to prove the effectiveness of the vibration device. The experimental results show that this novel vibration assisted polishing device developed in this study can remove more effectively the cutting marks left by last process and obviously reduce the workpiece surface roughness.

  7. A novel vibration assisted polishing device based on the flexural mechanism driven by the piezoelectric actuators

    Science.gov (United States)

    Wang, Guilian; Zhou, Xiaoqin; Ma, Peiqun; Wang, Rongqi; Meng, Guangwei; Yang, Xu

    2018-01-01

    The vibration assisted polishing has widely application fields because of higher machining frequency and better polishing quality, especially the polishing with the non-resonant mode that is regarded as a kind of promising polishing method. This paper reports a novel vibration assisted polishing device, consisting of the flexible hinge mechanism driven by the piezoelectric actuators, which is suitable for polishing planes or curve surfaces with slow curvature. Firstly, the generation methods of vibration trajectory are investigated for the same frequency and different frequency signals' inputs, respectively, and then the types of elliptic and Lissajous's vibration trajectories are generated respectively. Secondly, a flexural mechanism consisting of the right circular flexible hinges and the leaf springs is developed to produce two-dimensional vibration trajectory. Statics and dynamics investigating of this flexible mechanism are finished in detail. The analytical models about input and output compliances of the flexural mechanism are established according to the matrix-based compliance modeling, and the dynamic model of the flexural mechanism based on the Euler-Lagrange equation is also presented. The finite element model of the flexural mechanism was established to carry out the numerical simulation in order to testify the rationality of device design. Finally, the polishing experiment is carried out to prove the effectiveness of the vibration device. The experimental results show that this novel vibration assisted polishing device developed in this study can remove more effectively the cutting marks left by last process and obviously reduce the workpiece surface roughness.

  8. Wear characteristics of polished and glazed lithium disilicate ceramics opposed to three ceramic materials.

    Science.gov (United States)

    Saiki, Osamu; Koizumi, Hiroyasu; Akazawa, Nobutaka; Kodaira, Akihisa; Okamura, Kentaro; Matsumura, Hideo

    2016-01-01

    This study compared the wear characteristics of a heat-pressed lithium disilicate ceramic material opposed to feldspathic porcelain, a lithium disilicate glass ceramic, and zirconia materials. Ceramic plate specimens were prepared from feldspathic porcelain (EX-3 nA1B), lithium disilicate glass ceramics (e.max CAD MO1/C14), and zirconia (Katana KT 10) and then ground or polished. Rounded rod specimens were fabricated from heat-pressed lithium disilicate glass ceramic (e.max press LT A3) and then glazed or polished. A sliding wear testing apparatus was used for wear testing. Wear of glazed rods was greater than that of polished rods when they were abraded with ground zirconia, ground porcelain, polished porcelain, or polished lithium disilicate ceramics. For both glazed and polished rods, wear was greater when the rods were abraded with ground plates. The findings indicate that application of a polished surface rather than a glazed surface is recommended for single restorations made of heat-pressed lithium disilicate material. In addition, care must be taken when polishing opposing materials, especially those used in occlusal contact areas. (J Oral Sci 58, 117-123, 2016).

  9. Polish-Bulgarian-Russian, Bulgarian-Polish-Russian or Russian-Bulgarian-Polish dictionary?

    Directory of Open Access Journals (Sweden)

    Violetta Koseska-Toszewa

    2015-11-01

    Full Text Available Polish-Bulgarian-Russian, Bulgarian-Polish-Russian or Russian-Bulgarian-Polish dictionary? The trilingual dictionary (M. Duszkin, V. Koseska, J. Satoła and A. Tzoneva is being elaborated based on a working Polish-Bulgarian-Russian electronic parallel corpus authored by Maksim Duszkin, Violetta Koseska-Toszewa and Joanna Satoła-Staśkowiak, and works by A. Tzoneva. It is the first corpus comparing languages belonging to three different Slavic language groups: western, southern and eastern. Works on the dictionary are based on Gramatyka konfrontatywna bułgarsko-polska (Bulgarian-Polish confrontative grammar and the proposed there semantic-oriented interlanguage. Two types of classifiers have been introduced into the dictionary: classic and semantic. The trilingual dictionary will present a consistent and homogeneous set of facts of grammar and semantics. The Authors point out that in a traditional dictionary it is not clear for example whether aspect should be understood as imperfective / perfective form of a verb or as its meaning. Therefore in the dictionary forms and meaning are separated in a regular way. Imperfective verb form has two meanings: state and configuration of states and events culminating in state. Also perfective verb form has two meanings: event and configuration of states and events culminating in event. These meanings are described by the semantic classifiers, respectively, state and event, state1 and event1. The way of describing language units, mentioned in the article, gives a possibility to present language material (Polish, Bulgarian, Russian in any required order, hence the article’s title.

  10. Cannabinoids cases in polish athletes

    Directory of Open Access Journals (Sweden)

    A Pokrywka

    2009-07-01

    Full Text Available The aim of this study was to investigate the number of cases and the profiles of Polish athletes who had occasionally been using marijuana or hashish throughout the period of 1998-2004, with respect to: sex, age, and discipline of sport as well as the period of testing (in- and out-of-competition. Results of the study were compared with some data reported by other WADA accredited anti-doping laboratories. Totally, 13 631 urine samples taken from Polish athletes of both sexes, aged 10-67 years, performing 46 disciplines of sport were tested. Cannabinoids were detected in 267 samples. Among Polish athletes the relative number of positive THC (tetrahydrocannabinol samples was one of the highest in Europe. The group of young Polish athletes (aged 16-24 years was the most THC-positive. THC-positive cases were noted more frequently in male athletes tested during out of competitions. The so-called contact sports (rugby, ice hockey, skating, boxing, badminton, body building and acrobatic sports were those sports, where the higher risk of cannabis use was observed. The legal interpretation of some positive cannabinoids results would be difficult because of some accidental and unintentional use of the narcotics by sportsmen. It was concluded that national anti-doping organizations (NADO’s, which are competent to judge whether the anti-doping rules were violated, should take into account the possibility of non-intentional doping use of cannabinoids via passive smoking of marijuana.

  11. Well-Defined Silica Grafted Molybdenum Bis(imido) Catalysts for Imine Metathesis Reactions

    KAUST Repository

    Barman, Samir

    2017-04-06

    Novel site-isolated tetracoordinated molybdenum complexes possessing bis(imido) ligands, [(≡Si–O)2Mo(═NR)2] (R = t-Bu, 2,6-C6H3-i-Pr2), were immobilized on partially dehydroxylated silica (SiO2-200) by a rigorous surface organometallic chemistry protocol. The newly developed materials adorned with bis(imido) functional units, which were previously exploited mainly as spectator ligands on silica-supported olefin metathesis molybdenum catalysts, are found to be efficient heterogeneous catalytic systems for imine cross metathesis under mild conditions.

  12. Electrocatalytic properties of cobalt-molybdenum alloy precipitates in hydrogen evolution reaction

    International Nuclear Information System (INIS)

    Kuznetsov, V.V.; Kalinkina, A.A.; Pshenichkina, T.V.; Balabaev, V.V.

    2008-01-01

    Electrocatalytic activity of cobalt-molybdenum precipitates concerning hydrogen evolution in alkali solution has been studied. Electrode materials were prepared by electrochemical method in galvanostatic regime. It is demonstrated that hydrogen evolution rate in 1M NaOH at 293 K at the Co-Mo alloy is higher as compared with the pure cobalt precipitates prepared similarly. It is in accord with the increasing true area of the electrode surface, and, perhaps, with electronic structure of the prepared alloys. It is established that exchange current of the hydrogen reaction increases when molybdenum content rises in electrode precipitates in the interval 0-40 at.% [ru

  13. Molybdenum Metallopharmaceuticals Candidate Compounds - The "Renaissance" of Molybdenum Metallodrugs?

    Science.gov (United States)

    Jurowska, Anna; Jurowski, Kamil; Szklarzewicz, Janusz; Buszewski, Boguslaw; Kalenik, Tatiana; Piekoszewski, Wojciech

    2016-01-01

    Metal-based drugs, also called "metallopharmaceuticals" or "metallodrugs", are examples of sophisticated compounds that have been used in inorganic medicinal chemistry as therapeutic agents for a long time. Few of them have shown substantially promising results and many of them have been used in different phases of clinical trials. The Mo-based metallodrugs were successfully applied in the past for treating conditions such as anemia or Wilson's disease. Moreover, Mo complexes are supposed to exert their effect by intercalation/ cleavage of DNA/RNA, arrest of the cell cycle, and alteration of cell membrane functions. However, in the current literature, there are no reliable and in-depth reviews about the hypothetical therapeutic applications of all of the known molybdenum complexes as metallopharmaceuticals/ metallodrugs. The main emphasis was on the in-depth review of the potential applications of Mo-based complexes in medicinal chemistry as metallopharmaceuticals in treating diseases such as cancer and tumors, Wilson's disease, diabetes mellitus, Huntington's disease, atherosclerosis, and anemia. It must be emphasized that today the development of innovative and new Mo-based metalo-pharmaceuticals is not rapid, and hence the aim of this paper was also to inspire colleagues working in the field of Mo compounds who are trying to find "signpost" for research. The authors hope that this article will increase interest and initiate the Renaissance of Mo-compounds among medicinal inorganic chemists. This paper is the first review article in the literature that refers to and emphasizes many different and complex aspects of possible applications and capabilities of Mo-based metallodrugs.

  14. Development of on the machine process monitoring and control strategy in Robot Assisted Polishing

    DEFF Research Database (Denmark)

    Pilny, Lukas; Bissacco, Giuliano

    2015-01-01

    Robot Assisted Polishing (RAP) can be used to polish rotational symmetric and free form components achieving surface roughness down to Sa 10 nm. With the aim to enable unmanned robust and cost efficient application of RAP, this paper presents the development of a monitoring and control strategy...... for automatic detection of process end point as well as on the machine total surface characterization and local defects identification. The approach is based on a multisensory polishing arm allowing measurement of Acoustic Emission and process forces and a scattered light sensor mounted on the machine...

  15. Electroluminescence Analysis by Tilt Polish Technique of InP-Based Semiconductor Lasers

    Science.gov (United States)

    Ichikawa, Hiroyuki; Sasaki, Kouichi; Hamada, Kotaro; Yamaguchi, Akira

    2010-03-01

    We developed an effective electroluminescence (EL) analysis method to specify the degraded region of InP-based semiconductor lasers. The EL analysis method is one of the most important methods for failure analysis. However, EL observation was difficult because opaque electrodes surround an active layer. A portion of each electrode had to be left intact for wiring to inject the current. Thus, we developed a partial polish technique for the bottom electrode. Tilt polish equipment with a rotating table was introduced; a flat polished surface and a sufficiently wide remaining portion of the bottom electrode were obtained. As a result, clear EL from the back surface of the laser was observed.

  16. Vacuum atomization of powder and shaping of net-shape components of molybdenum

    International Nuclear Information System (INIS)

    Devillard, Jacques.

    1979-01-01

    The paper reports an electron beam process and furnace for the production of spherical molybdenum powders of varying particle size prepared by vacuum atomization. Technical parameters of this process are discussed in an industrial plant. Powders of molybdenum alloys were extruded into round bars and tubes and the conditions of extrusion are specified. The mechanical properties in the as extruded state and after recrystallization were found to depend on the interstitial elements content and the particle size of the powder used. Tubes were cold bent to a 5 cm radius of curvature before or after uncanning. In the as-extruded state the tubes have a ligneous surface, the roughness depends on the particle size of the powder used. A new step of development in shaping molybdenum tubes is investigated and the cost of this process in an industrial plant is discussed [fr

  17. Buta-1,3-diene hydrogenation on a deuterium sulphide-treated molybdenum disulphide catalyst

    International Nuclear Information System (INIS)

    Barbour, J.; Campbell, K.C.

    1982-01-01

    Deuterium, introduced as D 2 S to a molybdenum disulphide catalyst, has been found to exchange with gas-phase hydrogen and to be incorporated into hydrocarbon products when buta-1,3-diene is hydrogenated on the catalyst; evidence is presented for the participation of hydrogen present on the surface as SH groups. (author)

  18. Preparation of supported vanadium and molybdenum oxide catalysts using metal acetylacetonate complexes

    NARCIS (Netherlands)

    van Hengstum, A.J.; van Ommen, J.G.; Bosch, H.; Gellings, P.J.

    1983-01-01

    Supported vanadium and molybdenum oxide catalysts were prepared by reaction of the corresponding acetylacetonate complex in a non-aqueous solution with the surface hydroxyl groups of the carrier. Continuous or batch adsorption of the metal acetylacetonate from toluene, as well as wet impregnation

  19. Mechanistic, kinetic, and processing aspects of tungsten chemical mechanical polishing

    Science.gov (United States)

    Stein, David

    This dissertation presents an investigation into tungsten chemical mechanical polishing (CMP). CMP is the industrially predominant unit operation that removes excess tungsten after non-selective chemical vapor deposition (CVD) during sub-micron integrated circuit (IC) manufacture. This work explores the CMP process from process engineering and fundamental mechanistic perspectives. The process engineering study optimized an existing CMP process to address issues of polish pad and wafer carrier life. Polish rates, post-CMP metrology of patterned wafers, electrical test data, and synergy with a thermal endpoint technique were used to determine the optimal process. The oxidation rate of tungsten during CMP is significantly lower than the removal rate under identical conditions. Tungsten polished without inhibition during cathodic potentiostatic control. Hertzian indenter model calculations preclude colloids of the size used in tungsten CMP slurries from indenting the tungsten surface. AFM surface topography maps and TEM images of post-CMP tungsten do not show evidence of plow marks or intergranular fracture. Polish rate is dependent on potassium iodate concentration; process temperature is not. The colloid species significantly affects the polish rate and process temperature. Process temperature is not a predictor of polish rate. A process energy balance indicates that the process temperature is predominantly due to shaft work, and that any heat of reaction evolved during the CMP process is negligible. Friction and adhesion between alumina and tungsten were studied using modified AFM techniques. Friction was constant with potassium iodate concentration, but varied with applied pressure. This corroborates the results from the energy balance. Adhesion between the alumina and the tungsten was proportional to the potassium iodate concentration. A heuristic mechanism, which captures the relationship between polish rate, pressure, velocity, and slurry chemistry, is presented

  20. Atomic-scale finishing of carbon face of single crystal SiC by combination of thermal oxidation pretreatment and slurry polishing

    Science.gov (United States)

    Deng, Hui; Liu, Nian; Endo, Katsuyoshi; Yamamura, Kazuya

    2018-03-01

    Single-crystal silicon carbide (4H-SiC) has a range of useful physical, mechanical and electronic properties that make it a promising material for fabrication of next-generation semiconductor devices. In this work, we report a hybrid polishing process combining thermal oxidation pretreatment and soft abrasive polishing to realize the damage-free and atomic-scale smooth finishing of the carbon face of 4H-SiC. By thermal oxidation pretreatment, the hardness of the carbon face has been reduced from 4.6 GPa to 1.7 GPa, which enables highly efficient polishing using CeO2 slurry. For conventional CeO2 slurry polishing without pretreatment, scratches still existed after a long polishing duration for 16 h. The probable scratch removal mechanism in CeO2 slurry polishing has been proposed based on surface morphology changes during polishing. Whereas a scratch-free surface with well-ordered SiC atomic steps was obtained within a short polishing duration of only 3 h when polishing was conducted on a thermally oxidized surface. Our results demonstrate that hybrid polishing combining surface pretreatment and soft abrasive polishing is a promising approach to realize the damage-free and atomic-scale smooth finishing of the carbon face of 4H-SiC.

  1. MeV ion beam polishing of anodically grown alumina

    International Nuclear Information System (INIS)

    Daudin, B.; Martin, P.

    1988-01-01

    When bombarded with 1 MeV N + ions, the surface of anodically grown alumina films is smoothened. This polishing effect was studied as a function of the ion bombardment fluence and of the substrate temperature in the range 80 - 650 K. The techniques used to characterize the surface roughness were Rutherford Backscattering Spectrometry, Scanning Electron Microscopy and small angle X-rays diffusion. It is suggested that atomic and/or electronic sputtering is responsible for the smoothing effect which was observed

  2. Bibliographic study on molybdenum biokinetics. Literaturstudie zur Biokinetik von Molybdaen

    Energy Technology Data Exchange (ETDEWEB)

    Erzberger, A.

    1988-05-01

    This bibliographical study compiles and analyzes findings about the metabolism and resorption of molybdenum. Besides including studies on the physiology of molybdenum 99, a general survey is given on molybdenum in the environment and on its physiological behaviour. In particular, information on the dependence of molybdenum resorption on various factors, such as the chemical form, antagonisms etc., are gathered from literature. These factors have to be considered for sensibly carrying out necessary experiments.

  3. Smooth polishing of femtosecond laser induced craters on cemented carbide by ultrasonic vibration method

    Science.gov (United States)

    Wang, H. P.; Guan, Y. C.; Zheng, H. Y.

    2017-12-01

    Rough surface features induced by laser irradiation have been a challenging for the fabrication of micro/nano scale features. In this work, we propose hybrid ultrasonic vibration polishing method to improve surface quality of microcraters produced by femtosecond laser irradiation on cemented carbide. The laser caused rough surfaces are significantly smoothened after ultrasonic vibration polishing due to the strong collision effect of diamond particles on the surfaces. 3D morphology, SEM and AFM analysis has been conducted to characterize surface morphology and topography. Results indicate that the minimal surface roughness of Ra 7.60 nm has been achieved on the polished surfaces. The fabrication of microcraters with smooth surfaces is applicable to molding process for mass production of micro-optical components.

  4. Process for fabrication of molybdenum-base wrought products

    International Nuclear Information System (INIS)

    1977-01-01

    A process for the fabrication of molybdenum-base wrought products is described comprising the steps of providing a molybdenum material containing at least 50% molybdenum in a substantially fully annealed condition, warming the said material to a temperature in the range of from 500 0 F to 1200 0 F, and deforming the warmed said material into a wrought product. (author)

  5. Grain Boundary Segregation and Intergranular Fracture in Molybdenum

    Science.gov (United States)

    Kumar, A.; Eyre, B. L.

    1980-04-01

    The refractory group VIA metals generally exhibit intergranular brittleness when they are in the recrystallized condition. This causes severe problems in their fabrication and places major limitations on their practical application. The phenomenon, generally referred to as recrystallization embrittlement, results in large increases in the ductile-to-brittle transition temperature and a change in fracture mode in the lower shelf regime from cleavage to intergranular with a significant decrease in ductility. The embrittlement is widely considered to be associated with interstitial impurities but there have been few systematic studies to elucidate their effects. The present paper reports results from a systematic study of segregation and intergranular embrittlement in binary molybdenum-oxygen and ternary molybdenum-oxygen-carbon alloys. The experiments were carried out on 'bamboo' specimens containing a series of identical single grain boundaries traversing their cross-sections. Measurements have been made of the activation energy for oxygen segregation to grain boundaries in the binary molybdenum-oxygen alloys. The influence of carbon additions on the level of oxygen segregation has also been determined. In addition, the influence of oxygen segregation on the energy to fracture has been studied and this has involved quantitative measurements of the work of fracture and the contribution made by plastic deformation. Results from metallographic studies are also presented, showing the effects of segregation on fracture surface topography and dislocation structures immediately adjacent to the fracture surfaces. In discussing the results we consider the thermodynamics of oxygen segregation to grain boundaries and the role played by carbon in inhibiting segregation. It is proposed that carbon either increases the effective solubility of oxygen in molybdenum or acts as a trap for oxygen atoms. In either case the effect is to reduce the driving force for segregation. We also

  6. Simple Formation of Nanostructured Molybdenum Disulfide Thin Films by Electrodeposition

    Directory of Open Access Journals (Sweden)

    S. K. Ghosh

    2013-01-01

    Full Text Available Nanostructured molybdenum disulfide thin films were deposited on various substrates by direct current (DC electrolysis form aqueous electrolyte containing molybdate and sulfide ions. Post deposition annealing at higher temperatures in the range 450–700°C transformed the as-deposited amorphous films to nanocrystalline structure. High temperature X-ray diffraction studies clearly recorded the crystal structure transformations associated with grain growth with increase in annealing temperature. Surface morphology investigations revealed featureless structure in case of as-deposited surface; upon annealing it converts into a surface with protruding nanotubes, nanorods, or dumbbell shape nanofeatures. UV-visible and FTIR spectra confirmed about the presence of Mo-S bonding in the deposited films. Transmission electron microscopic examination showed that the annealed MoS2 films consist of nanoballs, nanoribbons, and multiple wall nanotubes.

  7. High heat load test of molybdenum

    Energy Technology Data Exchange (ETDEWEB)

    Tanabe, T. (Faculty of Engineering, Osaka Univ., Suita (Japan)); Fujine, M.; Noguchi, H. (Daido Steel Co. Ltd., Nagoya (Japan)); Yagi, Y.; Hirano, Y.; Shimizu, H. (Electrotechnical Lab., Umezono, Tsukuba (Japan)); Akiba, M.; Araki, M. (Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan)); Kubota, Y.; Miyahara, A. (National Inst. for Fusion Science, Nagoya (Japan))

    1993-03-01

    Three different types of molybdenum, powder metallurgical polycrystalline (PM-Mo), and as-forged polycrystalline and single crystalline of highly purified electron-beam-melted Mo (AFEB-Mo and SCEB-Mo), have been subjected to high heat load test with neutral beam injection (NBI) stands at Japan Atomic Energy Research Institute (JAERI) and National Institute for Fusion Science (NIFS). These materials have also been tested as a movable limiter in a reversed field pinch machine (RFP:TPE-1RM15) in Electrotechnical Laboratory (ETL). The results are summarized as follows. The SCEB-Mo shows the least damage with slight local melting after a very high heat load of 260 MW/m[sup 2] for 250 ms with NBI, while for the PM-Mo the whole irradiated area melt with many craters due to impurity gas evaporation under less heat load (200 ms). All movable limiter heads of the RFP are severely damaged with partial melting. The appearance of the SCEB-Mo limiter after melting is not good and shows the crystalline cleavage. However, SEM observation of the microstructure opposes the surface appearance. In the SCEB-Mo, appreciable recrystallization is not observed and hence no crack is seen to go into the bulk except the crystalline cleavage. In the PM-Mo, on the other hand, the resolidification to columnar grains as well as the recrystallization is apparent, and the cracks not only go along the columnar grains but also separate the recrystallized region from the matrix. In the AFEB-Mo, a slight grain growth occurs and several cracks enter deep along the grain boundaries. Thus the SCEB-Mo is a very nice plasma-facing material if used under the critical heat load for melting. (orig.).

  8. Spectrographic analysis of uranium-molybdenum alloys

    International Nuclear Information System (INIS)

    Roca, M.

    1967-01-01

    A spectrographic method of analysis has been developed for uranium-molybdenum alloys containing up to 10 % Mo. The carrier distillation technique, with gallium oxide and graphite as carriers, is used for the semiquantitative determination of Al, Cr, Fe, Ni and Si, involving the conversion of the samples into oxides. As a consequence of the study of the influence of the molybdenum on the line intensities, it is useful to prepare only one set of standards with 0,6 % MoO 3 . Total burning excitation is used for calcium, employing two sets of standards with 0,6 and 7.5 MoO 3 . (Author) 5 refs

  9. Investigation of iron-bismuth-molybdenum catalysts

    International Nuclear Information System (INIS)

    Ven'yaminov, S.A.; Pitaeva, A.N.; Barannik, G.B.; Plyasova, L.M.; Maksimovskaya, R.I.; Kustova, G.N.

    1977-01-01

    Using the methods of roentgenography, derivatography, EPR-and infrared-spectroscopy, the phase composition of an iron-bismut molybdenum system is investigated. It is shown that the method of introducing iron additives substantially affects the phase composition of the system. Interaction of a mixture of bismuth and iron hydroxides with a molybdic acid solution results in the formation of bismuth and iron molybdates. If iron hydroxide reacts with previously synthesized bismuth molybdate, a compound containing bismuth, molybdenum, and iron (the X-phase) is formed in the specimens along with the bismuth and iron molybdates

  10. Measurement of Actinides in Molybdenum-99 Solution Analytical Procedure

    Energy Technology Data Exchange (ETDEWEB)

    Soderquist, Chuck Z. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Weaver, Jamie L. [Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-11-01

    This document is a companion report to a previous report, PNNL 24519, Measurement of Actinides in Molybdenum-99 Solution, A Brief Review of the Literature, August 2015. In this companion report, we report a fast, accurate, newly developed analytical method for measurement of trace alpha-emitting actinide elements in commercial high-activity molybdenum-99 solution. Molybdenum-99 is widely used to produce 99mTc for medical imaging. Because it is used as a radiopharmaceutical, its purity must be proven to be extremely high, particularly for the alpha emitting actinides. The sample of 99Mo solution is measured into a vessel (such as a polyethylene centrifuge tube) and acidified with dilute nitric acid. A gadolinium carrier is added (50 µg). Tracers and spikes are added as necessary. Then the solution is made strongly basic with ammonium hydroxide, which causes the gadolinium carrier to precipitate as hydrous Gd(OH)3. The precipitate of Gd(OH)3 carries all of the actinide elements. The suspension of gadolinium hydroxide is then passed through a membrane filter to make a counting mount suitable for direct alpha spectrometry. The high-activity 99Mo and 99mTc pass through the membrane filter and are separated from the alpha emitters. The gadolinium hydroxide, carrying any trace actinide elements that might be present in the sample, forms a thin, uniform cake on the surface of the membrane filter. The filter cake is first washed with dilute ammonium hydroxide to push the last traces of molybdate through, then with water. The filter is then mounted on a stainless steel counting disk. Finally, the alpha emitting actinide elements are measured by alpha spectrometry.

  11. Finishing and polishing of a poly (fluoroalkoxyphosphazene) resilient denture liner.

    Science.gov (United States)

    Loney, R W; Moulding, M B; Hacker, C H; Ritsco, R G

    1994-01-01

    A raised ridge of Novus resilient denture liner was removed from samples using one of three burs, three stones, or a coarse sandpaper disc. Samples were polished using pumice alone, tin oxide alone, or both agents. A flat, unfinished sample served as a control. Average surface roughness of control samples was 0.96 microns. Average surface roughness measurements for reduced samples ranged from 7.21 microns (sandpaper disc) to 3.34 microns (Prolastic wheel). Without polishing, sandpaper discs and serrated burs produced rougher surfaces than stones or the nonserrated bur. The sandpaper disc reduced the liner the quickest. There were no significant differences between treatments or controls after the use of pumice alone or after the use of a combination of pumice and tin oxide. An acceptable finishing protocol for this poly(fluoroalkoxyphosphazene) resilient liner appears to differ from that previously established for a silicone resilient denture liner.

  12. Polish energy-system modernisation

    International Nuclear Information System (INIS)

    Drozdz, M.

    2003-01-01

    The Polish energy-system needs intensive investments in new technologies, which are energy efficient, clean and cost effective. Since the early 1990s, the Polish economy has had practically full access to modern technological devices, equipment and technologies. Introducing new technologies is a difficult task for project teams, constructors and investors. The author presents a set of principles for project teams useful in planning and energy modernisation. Several essential features are discussed: Energy-efficient appliances and systems; Choice of energy carriers, media and fuels; Optimal tariffs, maximum power and installed power; Intelligent, integrated, steering systems; Waste-energy recovery; Renewable-energy recovery. In practice there are several difficulties connected with planning and realising good technological and economic solutions. The author presents his own experiences of energy-system modernisation of industrial processes and building new objects. (Author)

  13. FINANCIAL SECURITY OF POLISH HOUSEHOLDS

    Directory of Open Access Journals (Sweden)

    Agnieszka Kozera

    2016-09-01

    Full Text Available  A household’s fi nancial security is essential for the satisfaction of the needs and wants of its members, both communal and individual. It constitutes a kind of foundation for all of a household’s fi nancial decisions that impact its standard of living. The article aims to assess the level of fi nancial security of Polish households in 2005–2013. The research draws on data from Genworth Index, HBS conducted by the Central Statistical Offi ce (GUS and Social Diagnosis (Diagnoza społeczna overseen by the Social Monitoring Council. The study shows that Poland is characterized by a low level of fi nancial security relative to other European countries, especially Western and Scandinavian. More than three-quarters of Polish households experience fi nancial problems and exhibit both a low propensity to save, and low savings rates.

  14. Energy savings in Polish buildings

    Energy Technology Data Exchange (ETDEWEB)

    Markel, L.C.; Gula, A.; Reeves, G.

    1995-12-31

    A demonstration of low-cost insulation and weatherization techniques was a part of phase 1 of the Krakow Clean Fossil Fuels and Energy Efficient Project. The objectives were to identify a cost-effective set of measures to reduce energy used for space heating, determine how much energy could be saved, and foster widespread implementation of those measures. The demonstration project focused on 4 11-story buildings in a Krakow housing cooperative. Energy savings of over 20% were obtained. Most important, the procedures and materials implemented in the demonstration project have been adapted to Polish conditions and applied to other housing cooperatives, schools, and hospitals. Additional projects are being planned, in Krakow and other cities, under the direction of FEWE-Krakow, the Polish Energie Cities Network, and Biuro Rozwoju Krakowa.

  15. Confocal Raman spectrocopy for the analysis of nail polish evidence.

    Science.gov (United States)

    López-López, Maria; Vaz, Joana; García-Ruiz, Carmen

    2015-06-01

    Nail polishes are cosmetic paints that may be susceptible of forensic analysis offering useful information to assist in a crime reconstruction. Although the nail polish appearance could allow a quick visual identification of the sample, this analysis is subjected to the perception and subjective interpretation of the forensic examiner. The chemical analysis of the nail polishes offers great deal of information not subjected to analyst interpretation. Confocal Raman spectroscopy is a well-suited technique for the analysis of paints due to its non-invasive and non-destructive nature and its ability to supply information about the organic and inorganic components of the sample. In this work, 77 regular and gel nail polishes were analyzed with confocal Raman spectroscopy using two laser wavelengths (532 and 780 nm). The sample behavior under the two laser wavelengths and the differences in the spectra taken at different points of the sample were studied for each nail polish. Additionally, the spectra obtained for all the nail polishes were visually compared. The results concluded that the longer laser wavelength prevents sample burning and fluorescence effects; the similarity among the spectra collected within the sample is not directly related with the presence of glitter particles; and 64% of the samples analyzed showed a characteristic spectrum. Additionally, the use of confocal Raman spectroscopy for the forensic analysis of nail polishes evidence in the form of flakes or smudges on different surfaces were studied. The results showed that both types of evidence can be analyzed by the technique. Also, two non-invasive sampling methods for the collection of the evidence from the nails of the suspect or the victim were proposed: (i) to use acetone-soaked cotton swabs to remove the nail varnishes and (ii) to scrape the nail polish from the nail with a blade. Both approaches, each exhibiting advantages and drawbacks in terms of transport and handling were appropriate

  16. Earnings Management in Polish Companies

    OpenAIRE

    Brzeszczyński, Janusz; Gajdka, Jerzy; Schabek, Tomasz

    2012-01-01

    This paper presents results of the investigation of a phenomenon known as "earnings management'' (EM) among the companies listed on the Polish stock market. The distribution of earnings per share (EPS) for the stocks around the threshold value of "zero" and the threshold of "recent performance" was analyzed in the period of years 1997-2010. Moreover, the changes of earnings for the stocks, which are suspected to manipulate their earnings, were also investigated. The results, which indicate as...

  17. LOVE in English and Polish

    Directory of Open Access Journals (Sweden)

    Małgorzata Brożyna Reczko

    2017-12-01

    Full Text Available LOVE in English and Polish The paper presents a sample contrastive analysis of the linguistic picture of love in English and Polish. The material used in the survey is drawn from lexicographic data, including the British National Corpus and Narodowy Korpus Języka Polskiego [National Corpus of Polish]. The paper focuses on the similarities and differences in conceptualizing the abstract concept of love in the English and Polish languages. An analytical method, developed by Bartmiński and associates, serves as the theoretical basis for the reconstruction of the linguistic picture of the world.   MIŁOŚĆ w języku angielskim i polskim Niniejszy artykuł to próba kontrastywnego porównania językowego obrazu świata MIŁOŚCI w języku angielskim i polskim. Materiał badawczy pochodzi głównie ze źródeł leksykograficznych: słowników oraz korpusów (Narodowego Korpusu Języka Polskiego oraz z korpusu języka angielskiego British National Corpus. Celem badania było poszukiwanie podobieństw i różnic w konceptualizacji MIŁOŚCI w tych dwóch językach. Metoda badawcza została zaczerpnięta z prac J. Bartmińskiego i dotyczy rekonstrukcji językowego obrazu świata różnych pojęć.

  18. Enamel demineralization after different methods of interproximal polishing.

    Science.gov (United States)

    Hellak, Andreas F; Riepe, Esther M; Seubert, Andreas; Korbmacher-Steiner, Heike M

    2015-11-01

    The aim of this in vitro study was to investigate the demineralization rate in human enamel after interproximal polishing (IPP) and to detect possible correlations with the IPP method used, with special emphasis on the surface characteristics of the enamel being treated. This in vitro study tested five IPP systems (Profin Directional System®, Intensiv ProxoStrip®, OS discs®, ARS Safe-Tipped Bur Kit® and Ortho-Strips Set®) that are currently available on the market. Each of the five examination groups comprised 12 randomly selected teeth, while the control group consisted of six teeth. The teeth were placed in an artificial model for each group. The proximal contacts were then resolved by IPP. To allow detection of any surface characteristics, one surface was not further processed after IPP, while the other side was additionally polished. After IPP, the teeth were exposed to a pH-cycling model with alternating phases of demineralization and remineralization. Substance loss was analyzed using optical emission spectrometry. Data were subjected to simple analysis of variance (ANOVA) performed with Tukey's test. Comparison between the groups with and without polishing was conducted using the t test for independent samples. The significance level was set at p Rotor Stripping® system (ARS; 145.34 ± 20.37 μm). In all of the examination groups, subsequent polishing of the surfaces did not significantly reduce the amount of demineralization (polished 119.64 ± 28.61 μm; unpolished 114.16 ± 28.61 μm). No correlation between surface morphology and the degree of susceptibility of human enamel was detected. However, it must be taken into consideration that there was no potential bacterial colonization in this in vitro erosive set-up. Thus, in contrast to previous explanations, the outermost fluorapatite layer and the individual composition of the enamel may have a greater impact on the solubility of the enamel and the amount of enamel loss after IPP than

  19. Removing Molybdenum with the Microalgae Extracted from the Wastewater in Semiconductor Plants

    Science.gov (United States)

    Chiu, Yi-Chuan

    2017-04-01

    It has been well recognized that algae biomass can treat highly contaminated water in an effective way. Algae can grows in the natural environment without any care and can be efficiently cultivated. Both of living algae and dry algae biomass have been tested to absorb many kinds of toxic pollutants, because there are multiple functional groups on the algae surface capable of binding molybdenum. Therefore, algae become a good choice for the treatment of molybdenum in contaminated waters. In addition, in Taiwan, semiconductor industry is highly developed in the recent three decades. Subsequently, it is believed that some pollutants, such as molybdenum in this study, have become a threat to the surface water, groundwater and even the whole environment. In the previous studies, molybdenum is a well-known essential nutrient for the algae; therefore, the potential to remove molybdenum with algae from the wastewater is worth to be evaluated. The algae species, Chloroidium saccharophilum, was extracted from the wastewater in semiconductor plants for the study of removing molybdenum. A few sorption experiments have been conducted for evaluating the efficiency of removing molybdenum under different values of pH and molybdenum concentration. The absorption of Chloroidium saccharophilum can reach equilibrium in short times, which are 60 and 120 mins for molybdenum concentrations of 600 and 1200 ppb, respectively. The sorption experiments would accept the duration of 120 mins as the contact time and were performed at pH values of 6, 4 and 2 with different concentrations of molybdenum diluted by deionized water. The experiment data confirms that the isotherm has an excellent agreement on Langmuir adsorption model with the correlation coefficients (r2) of > 0.97. It demonstrates that the adsorption capacity (qmax) has an inverse relationship with pH value, which are 826, 2564 and 4761 mgkg-1 for pH 6, 4 and 2, respectively, while those of net enthalpy of adsorption (KL) are 3

  20. 19th Polish Control Conference

    CERN Document Server

    Kacprzyk, Janusz; Oprzędkiewicz, Krzysztof; Skruch, Paweł

    2017-01-01

    This volume contains the proceedings of the KKA 2017 – the 19th Polish Control Conference, organized by the Department of Automatics and Biomedical Engineering, AGH University of Science and Technology in Kraków, Poland on June 18–21, 2017, under the auspices of the Committee on Automatic Control and Robotics of the Polish Academy of Sciences, and the Commission for Engineering Sciences of the Polish Academy of Arts and Sciences. Part 1 deals with general issues of modeling and control, notably flow modeling and control, sliding mode, predictive, dual, etc. control. In turn, Part 2 focuses on optimization, estimation and prediction for control. Part 3 is concerned with autonomous vehicles, while Part 4 addresses applications. Part 5 discusses computer methods in control, and Part 6 examines fractional order calculus in the modeling and control of dynamic systems. Part 7 focuses on modern robotics. Part 8 deals with modeling and identification, while Part 9 deals with problems related to security, fault ...

  1. Effect of oxidizing environment on mechanical properties of molybdenum and TZM

    International Nuclear Information System (INIS)

    Liu, C.T.; Anderson, S.H.; Inouye, H.

    1978-10-01

    The effect of environment on mechanical properties of molybdenum and TZM was investigated in low-pressure (1.3-mPa) oxygen at 1150 0 C. Specimens of TZM picked up oxygen and lost carbon. The oxygen concentration increases linearly with exposure time, indicating that the chemisorption of oxygen molecules at the specimen surface, rather than bulk diffusion, controls the kinetics of oxygen absorption at 1150 0 C. Specimens of TZM increase in tensile strength and decrease in ductility with increasing oxygen content. Exposed TZM loses its ductility at elevated temperatures at an oxygen level of 500 ppM. The embrittlement is due to the formation of zones or oxide precipitates, which harden the alloy and promote the brittle fracture associated with cleavage and grain-boundary separation. Unalloyed molybdenum responds to the oxidizing environment quite differently from TZM. The molybdenum (containing no active element such as Ti and Zr) showed no internal oxidation at 1150 0 C. Instead, our results indicate that a trace of oxygen penetrated into molybdenum through its grain boundaries. This penetration raises the ductile-to-brittle transition temperature of molybdenum by 200 0 C lowers the ductility above 900 0 C. The ductility of oxygen-exposed molybdenum is virtually unaffected in the temperature range from 400 to 900 0 C. A ductility minimum (10%) is observed at 1350 0 C because of dynamic embrittlement effects; that is, diffusion of oxygen to grain boundaries or crack tips where high triaxial states of stress are generated during plastic deformation. This embrittlement can be totally eliminated by an increase in strain rate

  2. Protection of molybdenum and molybdenum - alloy thin films against low - temperature oxidation

    International Nuclear Information System (INIS)

    Schintlmeister, A.; Wilhartitz, P.

    2001-01-01

    Molybdenum is an interesting functional material for thin film applications like electrical connections in thin film transistor flat panel displays (TFT-FPD) or thin film solar cells (CIS). Despite its advantageous properties, the use of pure molybdenum has been restricted mainly because of its low stability against corrosion in moist air even at room temperature. In this paper it is described how thin films ( 2 . (author)

  3. Computer-Controlled Cylindrical Polishing Process for Large X-Ray Mirror Mandrels

    Science.gov (United States)

    Khan, Gufran S.; Gubarev, Mikhail; Speegle, Chet; Ramsey, Brian

    2010-01-01

    We are developing high-energy grazing incidence shell optics for hard-x-ray telescopes. The resolution of a mirror shells depends on the quality of cylindrical mandrel from which they are being replicated. Mid-spatial-frequency axial figure error is a dominant contributor in the error budget of the mandrel. This paper presents our efforts to develop a deterministic cylindrical polishing process in order to keep the mid-spatial-frequency axial figure errors to a minimum. Simulation software is developed to model the residual surface figure errors of a mandrel due to the polishing process parameters and the tools used, as well as to compute the optical performance of the optics. The study carried out using the developed software was focused on establishing a relationship between the polishing process parameters and the mid-spatial-frequency error generation. The process parameters modeled are the speeds of the lap and the mandrel, the tool s influence function, the contour path (dwell) of the tools, their shape and the distribution of the tools on the polishing lap. Using the inputs from the mathematical model, a mandrel having conical approximated Wolter-1 geometry, has been polished on a newly developed computer-controlled cylindrical polishing machine. The preliminary results of a series of polishing experiments demonstrate a qualitative agreement with the developed model. We report our first experimental results and discuss plans for further improvements in the polishing process. The ability to simulate the polishing process is critical to optimize the polishing process, improve the mandrel quality and significantly reduce the cost of mandrel production

  4. Nitriding molybdenum: Effects of duration and fill gas pressure when using 100-Hz pulse DC discharge technique

    International Nuclear Information System (INIS)

    Ikhlaq, U.; Saleem, S.; Shah, M. S.; Abbas, K.; Ahmad, R.; Hussain, T.; Abbas, M. S.; Shafiq, M.; Khan, I. A.

    2014-01-01

    Molybdenum is nitrided by a 100-Hz pulsed DC glow discharge technique for various time durations and fill gas pressures to study the effects on the surface properties of molybdenum. X-ray diffractometry (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM) are used for the structural and morphological analysis of the nitrided layers. Vickers' microhardness tester is utilized to investigate surface microhardness. Phase analysis shows the formation of more molybdenum nitride molecules for longer nitriding durations at fill gas pressures of 2 mbar and 3 mbar (1 bar = 10 5 Pa). A considerable increase in surface microhardness (approximately by a factor of 2) is observed for longer duration (10 h) and 2-mbar pressure. Longer duration (10 h) and 2-mbar fill gas pressure favors the formation of homogeneous, smooth, hard layers by the incorporation of more nitrogen. (physics of gases, plasmas, and electric discharges)

  5. Method for welding chromium molybdenum steels

    Science.gov (United States)

    Sikka, Vinod K.

    1986-01-01

    Chromium-molybdenum steels exhibit a weakening after welding in an area adjacent to the weld. This invention is an improved method for welding to eliminate the weakness by subjecting normalized steel to a partial temper prior to welding and subsequently fully tempering the welded article for optimum strength and ductility.

  6. Molybdenum-catalyzed deoxydehydration of vicinal diols

    DEFF Research Database (Denmark)

    Dethlefsen, Johannes Rytter; Lupp, Daniel; Oh, Byung Chang

    2014-01-01

    The commercially available (NH4)6Mo7O24 and other molybdenum compounds are shown to be viable substitutes for the typically employed rhenium compounds in the catalytic deoxydehydration of aliphatic diols into the corresponding alkenes. The transformation, which represents a model system for the v...

  7. Reaction of boron carbide with molybdenum disilicide

    International Nuclear Information System (INIS)

    Novikov, A.V.; Melekhin, V.F.; Pegov, V.S.

    1989-01-01

    The investigation results of interaction in the B 4 C-MoSi 2 system during sintering in vacuum are presented. Sintering of boron carbide with molybdenum disilicide is shown to lead to the formation of MoB 2 , SiC, Mo 5 Si 3 compounds, the presence of carbon-containing covering plays an important role in sintering

  8. Sulphur-bridged ruthenium–molybdenum complexes

    Indian Academy of Sciences (India)

    Unknown

    Ruthenium–molybdenum; 2-(arylazo)pyrimidine; sulphur bridged complexes; metal–ligand charge transfer. 1. Introduction. There has recently .... compound thus precipitated was washed with cold. H2O and dissolved in MeOH. An aqueous .... analysis (table 1) and spectral studies. 3.2 Spectral studies. IR spectra (table 1) of ...

  9. Paraelasticity in electron-irradiated molybdenum

    International Nuclear Information System (INIS)

    Beuneu, Brigitte; Quere, Yves.

    1981-11-01

    The relaxation of a radiation-induced point defect-most probably the rotation of a dumbell-is observed during isothermal anneals of irradiated molybdenum by resistivity measurements. The recovery of close pairs is not affected, in first analysis, by the presence of a uniaxial stress

  10. Exploring atomic defects in molybdenum disulphide monolayers

    KAUST Repository

    Hong, Jinhua

    2015-02-19

    Defects usually play an important role in tailoring various properties of two-dimensional materials. Defects in two-dimensional monolayer molybdenum disulphide may be responsible for large variation of electric and optical properties. Here we present a comprehensive joint experiment-theory investigation of point defects in monolayer molybdenum disulphide prepared by mechanical exfoliation, physical and chemical vapour deposition. Defect species are systematically identified and their concentrations determined by aberration-corrected scanning transmission electron microscopy, and also studied by ab-initio calculation. Defect density up to 3.5 × 10 13 cm \\'2 is found and the dominant category of defects changes from sulphur vacancy in mechanical exfoliation and chemical vapour deposition samples to molybdenum antisite in physical vapour deposition samples. Influence of defects on electronic structure and charge-carrier mobility are predicted by calculation and observed by electric transport measurement. In light of these results, the growth of ultra-high-quality monolayer molybdenum disulphide appears a primary task for the community pursuing high-performance electronic devices.

  11. Process for separation of tungsten and molybdenum by extraction

    International Nuclear Information System (INIS)

    Zelikman, A.N.; Voldman, G.M.; Rumyantsev, V.K.; Ziberov, G.N.; Kagermanian, V.S.

    1976-01-01

    A process for the separation of tungsten and molybdenum by extraction involves the addition of HCl or HNO 3 to an aqueous solution containing tungsten and molybdenum to obtain a pH from 0.5 to 4.3, and introduction of a stabilizer comprising water-soluble phosphorus salts and a complexing agent, hydrogen peroxide, in an amount from 1.5 to 2 mole per 1 g-atom of the total content of tungsten and molybdenum. Then molybdenum is selectively extracted from the resulting aqueous solution with tri-n-butylphosphate with equal volumetric proportioning of the aqueous and organic solutions. Re-extraction of molybdenum and partially tungsten is carried out from the organic extracting agent with an alkali or soda solution. The process makes possible the preparation of tungsten solution containing no more than 0.001 g/l of molybdenum, and an increase in the degree of extraction of tungsten and molybdenum

  12. Bio-polishing sludge adsorbents for dye removal

    Directory of Open Access Journals (Sweden)

    Zaini Muhammad Abbas Ahmad

    2016-12-01

    Full Text Available The objective of this work is to evaluate the removal of methylene blue dye by bio-polishing sludge-based adsorbents. The adsorbents were characterized according to the specific surface area, pH upon the treatment and surface functional groups. The adsorption of dye was carried out at room temperature, and the adsorption data were analyzed using the isotherm and kinetics models. The bio-polishing sludge is rich in ash content, and the presence of surface functional groups varied with the treatment strategies. The specific surface area of adsorbents is between 7.25 and 20.8 m2/g. Results show that the maximum removal of methylene blue by sludge adsorbents was observed to have the following order: untreated sludge (SR > zinc chloride-treated (SZ > microwave-dried (SW = potassium carbonate-treated (SK > acid-washed (SH. The maximum adsorption capacities for SR and SZ as predicted by the Langmuir model are 170 and 135 mg/g, respectively. Although SR demonstrates a higher maximum removal than SZ, the latter exhibits greater removal intensity and rate constant even at high dye concentration. The bio-polishing sludge is a promising adsorbent for dye wastewater treatment.

  13. An Overview of Polish Martial Arts

    Directory of Open Access Journals (Sweden)

    Wojciech J. Cynarski

    2012-07-01

    Full Text Available The purpose of this study is to explain the revival of Polish martial arts from the perspectives of cultural sociology, the sciences of physical culture, and the humanistic theory of martial arts. The Polish Martial Arts (Polskie Sztuki Walki are a subject still requiring serious scientific examination, even in Poland. There are few works concerning the history of Polish weapons, and most only describe techniques for wielding specific types of edged weapons. Nevertheless, there is a large group of enthusiasts trying to restore and cultivate the old Polish tradition, a tradition with heavy emphasis on the art of fencing. The author knows many of the people and facts presented here, from personal observation and from direct participation in these arts. As a disciple of the late Master Yoshio Sugino (10th-dan Kobudo Katori Shinto-ryu, he fought against the Polish saber champion, and he has taken part in joint exhibitions of Polish and Japanese fencing.

  14. Towards slide enhancement with the titanium-molybdenum wire?

    Science.gov (United States)

    Thiry, Pol; Barthélémi, Stéphane

    2010-12-01

    This study aims to improve the tribological properties of titanium-molybdenum wire. Following an analysis of the wire/bracket/ligation friction parameters and an overview of the technological research into means of reducing such friction,we set up several types of surface treatment in the laboratory by physical deposition in the vapor phase and using cold plasma technology. The specimens obtained underwent two types of tribological tests and were then subjected to traction and bending tests in order to determine the variations in their mechanical properties induced by the different types of treatment. For purposes of comparison, all the tests were conducted on untreated wire, TMA® Low-friction® wire and stainless steel wire and with two types of elastomeric ties. We were able to demonstrate some remarkable slide performances obtained using cold plasma nitriding while preserving the mechanical properties. A significant difference was observed relative to the other surface treatments.

  15. Molybdenum-tin as a solar cell metallization system

    Science.gov (United States)

    Boyd, D. W.; Radics, C.

    1981-01-01

    The operations of solar cell manufacture are briefly examined. The formation of reliable, ohmic, low-loss, and low-cost metal contacts on solar cells is a critical process step in cell manufacturing. In a commonly used process, low-cost metallization is achieved by screen printing a metal powder-glass frit ink on the surface of the Si surface and the conductive metal powder. A technique utilizing a molybdenum-tin alloy for the metal contacts appears to lower the cost of materials and to reduce process complexity. The ink used in this system is formulated from MoO3 with Sn powder and a trace amount of titanium resonate. Resistive losses of the resulting contacts are low because the ink contains no frit. The MoO3 is finally melted and reduced in forming gas (N2+H2) to Mo metal. The resulting Mo is highly reactive which facilitates the Mo-Si bonding.

  16. Materials and Breakdown Phenomena: Heterogeneous Molybdenum Metallic Films

    Directory of Open Access Journals (Sweden)

    Augusto Marcelli

    2017-05-01

    Full Text Available Technological activities to design, manufacture, and test new accelerating devices using different materials and methods is under way all over the world. The main goal of these studies is to increase the accelerating gradients and reduce the probability of radio-frequency (RF breakdown. Indeed, it is still not clear why, by increasing the intensity of the applied field, intense surface damage is observed in copper structures, limiting the lifetime and, therefore, the practical applications. A possible solution is represented by a coating of a relatively thick layer of molybdenum in order to improve the breakdown rate. molybdenum can be reliably grown on different substrates with a negligible strain and, for thicknesses up to 600 nm, with a resistivity < 100–150·μΩ cm. Moreover, Mo coatings with controlled composition, internal stress, and roughness may allow improving thermo-mechanical properties reaching values not attainable by uncoated copper. Although the Mo conductivity remains lower compared to Cu, a Mo coating represents a very interesting option for high gradient accelerator components manufactured in copper.

  17. The tourism attractiveness of Polish libraries

    OpenAIRE

    Miedzińska, Magdalena; Tanaś, Sławoj

    2009-01-01

    The aim of the article is to draw the reader's attention to the tourism attractiveness of renowned Polish libraries. These have attained a tourism function due to tourism exploration and penetration, but remain in the shadow of other Polish cultural assets. The article outlines the historical geography of Polish libraries, an analysis of tourism assets and an attempt to classify and catalogue libraries in Poland.

  18. Edge effect modeling of small tool polishing in planetary movement

    Science.gov (United States)

    Li, Qi-xin; Ma, Zhen; Jiang, Bo; Yao, Yong-sheng

    2018-03-01

    As one of the most challenging problems in Computer Controlled Optical Surfacing (CCOS), the edge effect greatly affects the polishing accuracy and efficiency. CCOS rely on stable tool influence function (TIF), however, at the edge of the mirror surface,with the grinding head out of the mirror ,the contact area and pressure distribution changes, which resulting in a non-linear change of TIF, and leads to tilting or sagging at the edge of the mirror. In order reduce the adverse effects and improve the polishing accuracy and efficiency. In this paper, we used the finite element simulation to analyze the pressure distribution at the mirror edge and combined with the improved traditional method to establish a new model. The new method fully considered the non-uniformity of pressure distribution. After modeling the TIFs in different locations, the description and prediction of the edge effects are realized, which has a positive significance on the control and suppression of edge effects

  19. Ion beam polishing for three-dimensional electron backscattered diffraction

    DEFF Research Database (Denmark)

    Saowadee, Nath; Agersted, Karsten; Ubhi, H.S.

    2013-01-01

    averaging and/or poor 3D-EBSD data quality. In this work a low kV focused ion beam was successfully implemented to automatically polish surfaces during 3D-EBSD of La- and Nb-doped strontium titanate of volume 12.6 × 12.6 × 3.0 μm. The key to achieving this technique is the combination of a defocused low k...

  20. Perceptions of and Attitudes towards Regional Varieties of Polish: Views from Two Polish Provinces

    Science.gov (United States)

    Milobog, Magdalena; Garrett, Peter

    2011-01-01

    This paper reports a study of perceptions and attitudes relating to regional varieties of Polish. The methodology followed folk linguistic approaches to attitudes research. Respondents in two Polish provinces were asked to draw on a map of Poland where they thought the main regional varieties of Polish were spoken, and then to name and…

  1. History of Polish gastrointestinal radiology.

    Science.gov (United States)

    Urbanik, A

    2003-12-01

    As early as several days after the publication of the information concerning Roentgen's discovery the first radiological examinations were performed in Poland. The new method was immediately introduced into medical practice, including gastroenterology. In that pioneer period the most important works were those by Walery Jaworski who was the first man in the world to perform an X-ray of gall stones as well as the stomach with the use of a contrast medium. In its more-than-a-hundred-year history Polish gastrointestinal radiology has attempted not only to catch up with the world science, but it also has made a considerable contribution to its development.

  2. Corporate Politics on Polish Millennials

    OpenAIRE

    Natalia Roślik

    2017-01-01

    In the very beginning of this particular paper, an author is trying to determine and describe who Millennials actually are. Then, the basis of Millennials definition is analysing corporation’s activity over the past years regarding this age group. The main goal of the thesis is to bring their specific futures out and describe what corporations on Polish job market are doing to encourage them to work in their offices. Especially in Poland within the last years, it is observed that big multinat...

  3. Polish Foundation for Energy Efficiency

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The Polish Foundation for Energy Efficiency (FEWE) was established in Poland at the end of 1990. FEWE, as an independent and non-profit organization, has the following objectives: to strive towards an energy efficient national economy, and to show the way and methods by use of which energy efficiency can be increased. The activity of the Foundation covers the entire territory of Poland through three regional centers: in Warsaw, Katowice and Cracow. FEWE employs well-known and experienced specialists within thermal and power engineering, civil engineering, economy and applied sciences. The organizer of the Foundation has been Battelle Memorial Institute - Pacific Northwest Laboratories from the USA.

  4. Acoustic Emission Based In-process Monitoring in Robot Assisted Polishing

    DEFF Research Database (Denmark)

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

    The applicability of acoustic emission (AE) measurements for in-process monitoring in the Robot Assisted Polishing (RAP) process was investigated. Surface roughness measurements require interruption of the process, proper surface cleaning and measurements that sometimes necessitate removal...... processing, the development of surface roughness in the RAP process can be monitored by AE measurement. The AE based monitoring allows in-process determination of the right moment for changing a polishing tool when applying a given set of parameters is no longer effective to create smoother surface, thus...

  5. Electrochemical Polishing Applications and EIS of a Vitamin B4-Based Ionic Liquid

    International Nuclear Information System (INIS)

    Wixtrom, Alex I.; Buhler, Jessica E.; Reece, Charles E.; Abdel-Fattah, Tarek M.

    2013-01-01

    Modern particle accelerators require minimal interior surface roughness for Niobium superconducting radio frequency (SRF) cavities. Polishing of the Nb is currently achieved via electrochemical polishing with concentrated mixtures of sulfuric and hydrofluoric acids. This acid-based approach is effective at reducing the surface roughness to acceptable levels for SRF use, but due to acid-related hazards and extra costs (including safe disposal of used polishing solutions), an acid-free method would be preferable. This study focuses on an alternative electrochemical polishing method for Nb, using a novel ionic liquid solution containing choline chloride, also known as Vitamin B 4 (VB 4 ). Potentiostatic electrochemical impedance spectroscopy (EIS) was also performed on the VB4-based system. Nb polished using the VB4-based method was found to have a final surface roughness comparable to that achieved via the acid-based method, as assessed by atomic force microscopy (AFM). These findings indicate that acid-free VB 4 -based electrochemical polishing of Nb represents a promising replacement for acid-based methods of SRF cavity preparation

  6. Contact pressure distribution during the polishing process of ceramic tiles: A laboratory investigation

    International Nuclear Information System (INIS)

    Sani, A S A; Hamedon, Z; Azhari, A; Sousa, F J P

    2016-01-01

    During the polishing process of porcelain tiles the difference in scratching speed between innermost and peripheral abrasives leads to pressure gradients linearly distributed along the radial direction of the abrasive tool. The aim of this paper is to investigate such pressure gradient in laboratory scale. For this purpose polishing tests were performed on ceramic tiles according to the industrial practices using a custom-made CNC tribometer. Gradual wear on both abrasives and machined surface of the floor tile were measured. The experimental results suggested that the pressure gradient tends to cause an inclination of the abraded surfaces, which becomes stable after a given polishing period. In addition to the wear depth of the machined surface, the highest value of gloss and finest surface finish were observed at the lowest point of the worn out surface of the ceramic floor tile corresponding to the point of highest pressure and lowest scratching speed. (paper)

  7. Contact pressure distribution during the polishing process of ceramic tiles: A laboratory investigation

    Science.gov (United States)

    Sani, A. S. A.; Sousa, F. J. P.; Hamedon, Z.; Azhari, A.

    2016-02-01

    During the polishing process of porcelain tiles the difference in scratching speed between innermost and peripheral abrasives leads to pressure gradients linearly distributed along the radial direction of the abrasive tool. The aim of this paper is to investigate such pressure gradient in laboratory scale. For this purpose polishing tests were performed on ceramic tiles according to the industrial practices using a custom-made CNC tribometer. Gradual wear on both abrasives and machined surface of the floor tile were measured. The experimental results suggested that the pressure gradient tends to cause an inclination of the abraded surfaces, which becomes stable after a given polishing period. In addition to the wear depth of the machined surface, the highest value of gloss and finest surface finish were observed at the lowest point of the worn out surface of the ceramic floor tile corresponding to the point of highest pressure and lowest scratching speed.

  8. Automated visual inspection for polished stone manufacture

    Science.gov (United States)

    Smith, Melvyn L.; Smith, Lyndon N.

    2003-05-01

    Increased globalisation of the ornamental stone market has lead to increased competition and more rigorous product quality requirements. As such, there are strong motivators to introduce new, more effective, inspection technologies that will help enable stone processors to reduce costs, improve quality and improve productivity. Natural stone surfaces may contain a mixture of complex two-dimensional (2D) patterns and three-dimensional (3D) features. The challenge in terms of automated inspection is to develop systems able to reliably identify 3D topographic defects, either naturally occurring or resulting from polishing, in the presence of concomitant complex 2D stochastic colour patterns. The resulting real-time analysis of the defects may be used in adaptive process control, in order to avoid the wasteful production of defective product. An innovative approach, using structured light and based upon an adaptation of the photometric stereo method, has been pioneered and developed at UWE to isolate and characterize mixed 2D and 3D surface features. The method is able to undertake tasks considered beyond the capabilities of existing surface inspection techniques. The approach has been successfully applied to real stone samples, and a selection of experimental results is presented.

  9. NEXAFS characterization and reactivity studies of bimetallic vanadium molybdenum oxynitride hydrotreating catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Kapoor, R.; Oyama, S.T. [Virginia Polytechnic Inst., Blacksburg, VA (United States); Fruehberger, B.; Chen, J.G. [Exxon Research and Engineering Company, Annandale, NJ (United States)

    1997-02-27

    The surface and bulk compositions of vanadium molybdenum oxynitride (V{sub 2}MoO{sub 1.7}N{sub 2.4}), prepared by temperature-programmed reaction (TPR) of vanadium molybdenum oxide (V{sub 2}MoO{sub 8}) with ammonia, have been characterized using near-edge X-ray absorption fine structure (NEXAFS) spectroscopy. The NEXAFS data were recorded at the K-edges of nitrogen and oxygen, the L-edge of vanadium, and the M-edge of molybdenum. The nitrogen K-edge region of V-Mo oxynitride shows the characteristic NEXAFS features of early-transition-metal nitrides, although these features are different from those of either VN or Mo{sub 2}N. Furthermore, comparison of the electron yield and fluorescence yield measurements also reveals that the oxidation state is different for vanadium near the surface region and for vanadium in the bulk, which is estimated to be 2.8 {+-} 0.3 and 3.8 {+-} 0.3, respectively. The oxidation state of bulk molybdenum is also estimated to be 4.4 {+-} 0.3. The X-ray diffraction pattern shows that the bulk phase of the bimetallic oxide is different from the pure monometallic oxide phases but the oxynitride has a cubic structure that resembles the pure vanadium and molybdenum nitride phases. The V-Mo oxide as prepared shows a preferential orientation of [001] crystallographic planes which is lost during the nitridation process. This shows that the solid state transformation V{sub 2}MoO{sub 8} {yields} V{sub 2}MoO{sub 1.7}N{sub 2.4} is not topotactic. 27 refs., 8 figs., 1 tab.

  10. Nucleation of microwave plasma CVD diamond on molybdenum (Mo) substrate

    International Nuclear Information System (INIS)

    Inderjeet, K.; Ramesh, S.

    2000-01-01

    Molybdenum is a metal, which is gaining increasing significance in industrial applications. The main use of Mo is as all alloying element added in small amounts to steel, irons and non- ferrous alloys in order to enhance the strength, toughness and wear resistance. Mo is also vastly being employed in the automotive and aircraft industries, mainly due to its low coefficient of friction. Diamond, on be other hand, is a unique material for innumerable applications because of its usual combination of physical and chemical properties. Several potential applications can be anticipated for diamond in many sectors including electronics, optics, as protective corrosion resistant coatings, cutting tools, etc. With the enhancement in science and technology, diamond microcrystals and thin films are now being produced from the vapour phase by a variety of chemical vapour deposition (CVD) techniques; such as microwave plasma CVD. With such technology being made available, it is envisage that diamond-coated molybdenum would further enhance the performance and to open up new avenue for Mo in various industries. Therefore, it is the aim of the present work to study the nucleation and growth of diamond particles on Mo surface by employing microwave plasma CVD (MAPCVD). In the present work, diamond deposition was carried out in several stages by varying the deposition distance. The nucleation and growth rate were studied using scanning electron microscopy (SEM). In addition, the existence of diamond was verified by X-ray diffraction (XRD) analysis. It has been found that the nucleation and growth rate of diamond particles were influenced by the deposition height between the substrate and plasma. Under the optimum condition, well defined diamond crystallites distributed homogeneously throughout the surface, could be obtained. Some of the important parameters controlling the deposition and growth of diamond particles on Mo surface are discussed. (author)

  11. Synthesis of borides in molybdenum implanted by B+ ions under thermal and electron annealing

    International Nuclear Information System (INIS)

    Kazdaev, Kh.R.; Akchulakov, M.T.; Bayadilov, E.M.; Ehngel'ko, V.I.; Lazarenko, A.V.; Chebukov, E.S.

    1989-01-01

    The possibility of formation of borides in the near surface layers of monocrystalline molybdenum implanted by boron ions at 35 keV energy under thermal and pulsed electron annealing by an electon beam at 140 keV energy is investigated. It is found that implantation of boron ions into molybdenum with subsequent thermal annealing permits to produce both molybdenum monoboride (α-MoB) and boride (γ-Mo 2 B) with rather different formation mechanisms. Formation of the α-MoB phase occurs with the temperature elevation from the centers appeared during implantation, while the γ-Mo 2 B phase appears only on heating the implanted layers up to definite temperature as a result of the phase transformation of the solid solution into a chemical compound. Pulsed electron annealing instead of thermal annealing results mainly in formation of molybdenum boride (γ-Mo 2 B), the state of structure is determined by the degree of heating of implanted layers and their durable stay at temperatures exceeding the threshold values

  12. Determination of trace amounts of impurities in molybdenum by spark source and glow discharge mass spectrometry

    International Nuclear Information System (INIS)

    Saito, Morimasa

    1994-01-01

    For the determination of trace and ultra-trace amounts of impurities in high-purity molybdenum, spark source mass spectrometry and glow discharge mass spectrometry were studied. In spark source mass spectrometry using the metal probe method, the liquid-helium cryogenic pump was used in order to protect the surface of the samples from oxidation. The theoretical relative sensitivity factors (Mo=1) calculated from physical properties were used. The analytical results obtained for molybdenum tablet and high-purity molybdenum were in good agreement with those obtained by other methods (atomic absorption spectrometry and others). In glow discharge mass spectrometry, the relative sensitivity factors were calculated by using the results obtained by spark source mass spectrometry and atomic absorption spectrometry, and this method was applied to the determination of ultra-trace amounts of impurities in ultra high-purity molybdenum and gave the satisfactory results. The detection limits (2σ, n=10) in the integration time of 600 s for U and Th were 0.6 ppb and 0.3 ppb, and the values for Al, Si, Cr, Mn and Cu were in the range of 10 ppb to 0.5 ppb. (author)

  13. Precision machining and polishing of scintillating crystals for large calorimeters and hodoscopes

    International Nuclear Information System (INIS)

    Wuest, C.R.; Fuchs, B.A.; Holdener, F.R.; Heck, J.L. Jr.

    1994-04-01

    New machining and polishing techniques have been developed for large scintillating crystal arrays such as the Barium Fluoride Electromagnetic Calorimeter for the GEM Detector at SSCL, the Crystal Clear Collaboration's cerium fluoride or lead tungstenate calorimeter at the proposed LHC and CERN, the PHENIX Detector at RHIC (barium fluoride), and the cesium iodide Calorimeter for the BaBar Detector at PEP-2 B Factory at SLAC. The machining and polishing methods to be presented in this paper provide crystalline surfaces without sub-surface damage or deformation as verified by Rutherford Back-scattering (RBS) analysis. Surface roughness of about 10--20 angstroms and sub-micron mechanical tolerances have been demonstrated on large barium fluoride crystal samples. Mass production techniques have also been developed for machining the proper angled surfaces and polishing up to five 50 cm long crystals at one time. These techniques utilize kinematic mount technology developed at LLNL to allow precision machining and polishing of complex surfaces. They will present this technology along with detailed surface studies of barium fluoride and cerium fluoride crystals polished with this technique

  14. A Study of Polishing Feature of Ultrasonic-Assisted Vibration Method in Bamboo Charcoal

    Directory of Open Access Journals (Sweden)

    Hsin-Min Lee

    2017-01-01

    Full Text Available Focusing on the feature of porosity in bamboo charcoal, this study applies the ultrasonic-assisted vibration method to perform surface polishing of the silicon wafer workpiece. The self-developed bamboo charcoal polishing spindle and ultrasonic- assisted vibration mechanism are attached to a single lapping machine. In the machining process, ultrasonic vibration enables the diamond slurry to smoothly pass through the microscopic holes of bamboo charcoal; the end of the bamboo charcoalis able to continue machining on the surface of the workpiece through the grasping force which exists in the microscopic holes. Under the polishing and machining parameters of ultrasonic-assisted vibration, with a diamond slurry concentration of 0.3%, the experimental results show a polishing time of 20 min, a loading of 25 N on the workpiece surface, a spindle speed of 1200 rpm, a vibration frequency of 30 kHz and the original surface roughness value of Ra 0.252 μm equals that of a mirror-like surface at Ra 0.017 μm. These research results prove that by using bamboo charcoal and ultrasonic-assisted vibration for polishing, a very good improvement can be achieved on the workpiece surface.

  15. Sexual activity of Polish adults.

    Science.gov (United States)

    Pastwa-Wojciechowska, Beata; Izdebski, Zbigniew

    2014-01-01

    The purpose of this research was to explore the subject of sexual activity in the Polish population, with special focus on age and gender differences, and sexual infidelity. Sexual activity is one of the basic factors in initiating and maintaining relationships. On the one hand, sexual activity enables us to meet natural needs and maintain an intimate relationship with another human being; on the other, it may allow us to overcome loneliness and social isolation by providing the opportunity to express feelings of closeness and unity. The research was conducted on a representative group of 3,200 Poles aged between 15-49, with the support of a well-known Polish research company - TNS OBOP. Face-to-face and Pencil and Paper (PAPI) interviews were carried out. The results focus on two main issues: the age and motives of sexual initiation among teenagers (with a significant percentage starting their sexual activity at the age of 15), and the quality of the sexual lives of adults (average number of sexual partners, sexual infidelity and sexual satisfaction). There is dependence between the type of relationship and the performance or non-performance of sexual activity, as well as the quality of the relationship. Among both adolescents and adults, remaining in a stable relationship (partnership or marriage) promotes loyalty. The performance of sexual goals turns out to be an important mechanism regulating the interpersonal aspects of a relationship, influencing their perception and evaluation.

  16. Sexual activity of Polish adults

    Directory of Open Access Journals (Sweden)

    Beata Pastwa-Wojciechowska

    2014-03-01

    Full Text Available Aim. The purpose of this research was to explore the subject of sexual activity in the Polish population, with special focus on age and gender differences, and sexual infidelity. Sexual activity is one of the basic factors in initiating and maintaining relationships. On the one hand, sexual activity enables us to meet natural needs and maintain an intimate relationship with another human being; on the other, it may allow us to overcome loneliness and social isolation by providing the opportunity to express feelings of closeness and unity. Material and method. The research was conducted on a representative group of 3,200 Poles aged between 15–49, with the support of a well-known Polish research company – TNS OBOP. Face-to-face and Pencil and Paper (PAPI interviews were carried out. Results. The results focus on two main issues: the age and motives of sexual initiation among teenagers (with a significant percentage starting their sexual activity at the age of 15, and the quality of the sexual lives of adults (average number of sexual partners, sexual infidelity and sexual satisfaction. Conclusion. There is dependence between the type of relationship and the performance or non-performance of sexual activity, as well as the quality of the relationship. Among both adolescents and adults, remaining in a stable relationship (partnership or marriage promotes loyalty. The performance of sexual goals turns out to be an important mechanism regulating the interpersonal aspects of a relationship, influencing their perception and evaluation.

  17. Evaluation of oxide dispersion strengthened (ODS) molybdenum and molybdenum-rhenium alloys

    International Nuclear Information System (INIS)

    Mueller, A.J.; Bianco, R.; Buckman, R.W. Jr.

    1999-01-01

    Oxide dispersion strengthened (ODS) molybdenum alloys being developed for high temperature applications possess excellent high temperature strength and creep resistance. In addition they exhibit a ductile-to-brittle transition temperature (DBIT) in the worked and stress-relieved condition under longitudinal tensile load well below room temperature. However, in the recrystallized condition, the DBTT maybe near or above room temperature, depending on the volume fraction of oxide dispersion and the amount of prior work. Dilute rhenium additions (7 and 14 wt.%) to ODS molybdenum were evaluated to determine their effect on low temperature ductility. The addition of 7 wt.% rhenium to the ODS molybdenum did not significantly enhance the mechanical properties. However, the addition of 14 wt.% rhenium to the ODS molybdenum resulted in a DBTT well below room temperature in both the stress-relieved and recrystallized condition. Additionally, the tensile strength of ODS Mo-14Re is greater than the base ODS molybdenum at 1,000 to 1,250 C

  18. High temperature high strength molybdenum and molybdenum-tungsten Ti-Zr-Hf-C alloys

    International Nuclear Information System (INIS)

    Eck, R.; Tinzl, J.

    1989-01-01

    TZM containing 0,5 % titanium, 0,08 % zirconium and 0,01-0,04 % carbon still is the most important molybdenum alloy. During the last years Zr-Hf-C and Hf-C containing alloys have been successfully developed and are in use at prominent consumers. Composition of Zr-Hf-C containing alloys could be optimized considering fabricability, low temperature ductility and required high temperature strength. Thermomechanical processes determine properties of semifinished and final products and are discussed in detail for the powder metallurgical way of production. Mechanical properties for short time and long term application of ZHM alloys are presented and discussed in comparison to the base metal and existing molybdenum based alloys. Demand for higher strength at usual temperature and higher working temperature not achievable with molybdenum base alloys led to the development of Zr-Hf-C and Hf-C dispersion strengthened molybdenum-tungsten alloys. Mechanical data of alloys are presented and advantages and disadvantages discussed in comparison to molybdenum based alloys. 8 refs., 17 figs., 1 tab. (Author)

  19. A clock reaction based on molybdenum blue.

    Science.gov (United States)

    Neuenschwander, Ulrich; Negron, Arnaldo; Jensen, Klavs F

    2013-05-30

    Clock reactions are rare kinetic phenomena, so far limited mostly to systems with ionic oxoacids and oxoanions in water. We report a new clock reaction in cyclohexanol that forms molybdenum blue from a noncharged, yellow molybdenum complex as precursor, in the presence of hydrogen peroxide. Interestingly, the concomitant color change is reversible, enabling multiple clock cycles to be executed consecutively. The kinetics of the clock reaction were experimentally characterized, and by adding insights from quantum chemical calculations, a plausible reaction mechanism was postulated. Key elementary reaction steps comprise sigmatropic rearrangements with five-membered or bicyclo[3.1.0] transition states. Importantly, numerical kinetic modeling demonstrated the mechanism's ability to reproduce the experimental findings. It also revealed that clock behavior is intimately connected to the sudden exhaustion of hydrogen peroxide. Due to the stoichiometric coproduction of ketone, the reaction bears potential for application in alcohol oxidation catalysis.

  20. Investigation of molybdenum pentachloride interaction with chlorine

    International Nuclear Information System (INIS)

    Salyulev, A.B.; Vovkotrub, Eh.G.; Strekalovskij, V.N.

    1993-01-01

    In Raman spectra of molybdenum pentachloride solutions in liquid chlorine lines were recorded in case of 397, 312, 410, 217 and 180 cm - 1 vibrations of ν 1 (A 1 '), ν 2 (A 1 '), ν 5 (E'), ν 6 (E') and ν 8 (E'') monomer (symmetry D 3h ) molecules of MoCl 5 . Interaction of molten molybdenum pentachloride with chlorine at increased (up to 6 MPa) pressures of Cl 2 was studied. In Raman spectra of its vapour distillation in liquid chlorine alongside with MoCl 5 lines appearance of new lines at 363 and 272 cm -1 , similar in their frequency to the ones calculated for the vibrations ν 1 (A 1g ) and ν 2 (E g ) of MoCl 6 molecules (symmetry O h ), was observed

  1. Molybdenum Dichalcogenides for Environmental Chemical Sensing

    OpenAIRE

    Zappa, Dario

    2017-01-01

    2D transition metal dichalcogenides are attracting a strong interest following the popularity of graphene and other carbon-based materials. In the field of chemical sensors, they offer some interesting features that could potentially overcome the limitation of graphene and metal oxides, such as the possibility of operating at room temperature. Molybdenum-based dichalcogenides in particular are among the most studied materials, thanks to their facile preparation techniques and promising perfor...

  2. Polish Industry and Art at CERN

    CERN Multimedia

    2000-01-01

    On 17 October 2000 the second Polish industrial and technological exhibition opened at CERN. The first one was held five years ago and nine of the companies that were present then have come back again this year. Six of those companies were awarded contracts with CERN in 1995. Three Polish officials were present at the Opening Ceremony today: Mrs Malgorzata Kozlowska, Under-secretary of State in the State Committee for Scientific Research, Mr Henryk Ogryczak, Under-secretary of State in Ministry of Economy and Prof. Jerzy Niewodniczanski, President of National Atomic Energy Agency. Professor Luciano Maiani welcomed the Polish delegation to CERN and stressed the important contribution of Polish scientists and industrialists to the work of the laboratory. Director General Luciano Maiani (back left) and head of SPL division Karl-Heinz Kissler (back right) visit the Poland at CERN exhibition… The exhibition offers Polish companies the opportunity to establish professional contacts with CERN. Nineteen companies...

  3. Tuning thermal conductivity in molybdenum disulfide by electrochemical intercalation

    Science.gov (United States)

    Zhu, Gaohua; Liu, Jun; Zheng, Qiye; Zhang, Ruigang; Li, Dongyao; Banerjee, Debasish; Cahill, David G.

    2016-01-01

    Thermal conductivity of two-dimensional (2D) materials is of interest for energy storage, nanoelectronics and optoelectronics. Here, we report that the thermal conductivity of molybdenum disulfide can be modified by electrochemical intercalation. We observe distinct behaviour for thin films with vertically aligned basal planes and natural bulk crystals with basal planes aligned parallel to the surface. The thermal conductivity is measured as a function of the degree of lithiation, using time-domain thermoreflectance. The change of thermal conductivity correlates with the lithiation-induced structural and compositional disorder. We further show that the ratio of the in-plane to through-plane thermal conductivity of bulk crystal is enhanced by the disorder. These results suggest that stacking disorder and mixture of phases is an effective mechanism to modify the anisotropic thermal conductivity of 2D materials. PMID:27767030

  4. Tuning thermal conductivity in molybdenum disulfide by electrochemical intercalation.

    Science.gov (United States)

    Zhu, Gaohua; Liu, Jun; Zheng, Qiye; Zhang, Ruigang; Li, Dongyao; Banerjee, Debasish; Cahill, David G

    2016-10-21

    Thermal conductivity of two-dimensional (2D) materials is of interest for energy storage, nanoelectronics and optoelectronics. Here, we report that the thermal conductivity of molybdenum disulfide can be modified by electrochemical intercalation. We observe distinct behaviour for thin films with vertically aligned basal planes and natural bulk crystals with basal planes aligned parallel to the surface. The thermal conductivity is measured as a function of the degree of lithiation, using time-domain thermoreflectance. The change of thermal conductivity correlates with the lithiation-induced structural and compositional disorder. We further show that the ratio of the in-plane to through-plane thermal conductivity of bulk crystal is enhanced by the disorder. These results suggest that stacking disorder and mixture of phases is an effective mechanism to modify the anisotropic thermal conductivity of 2D materials.

  5. Biomass as biosorbent for molybdenum ions

    Energy Technology Data Exchange (ETDEWEB)

    Yamaura, Mitiko; Santos, Jacinete L. dos; Damasceno, Marcos O.; Egute, Nayara dos S.; Moraes, Adeniane A.N.; Santos, Bruno Z., E-mail: myamaura@ipen.br, E-mail: jlsantos@ipen.br, E-mail: molidam@ipen.br, E-mail: nayara.egute@usp.br, E-mail: adenianemrs@ig.com.br, E-mail: bzsantos@gmail.com [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2013-07-01

    Biosorbents have been focused as renewable materials of low cost, and have been used for metal removal from the wastewater by adsorption phenomenon. Biosorbents are prepared of biomass, whose reactive sites in its chemical structure have affinity to bind to metal ions. In this work, performance of corn husk, sugarcane bagasse, coir, banana peel, fish scale, chitin and chitosan as biosorbents of molybdenum (VI) ions in aqueous medium was evaluated. The adsorption experiments were investigated in a batch system varying the pH solution from 0.5 to 12 and the contact time between the phases from 2 min to 70 min. {sup 99}Mo radioisotope was used as radioactive tracer for analysis of molybdenum ions by gamma spectroscopy using a HPGe detector. Results revealed that acidity of the solution favored the adsorption of Mo (VI) ions on the all biosorbents. Adsorption values higher than 85% were found on sugarcane bagasse, coir, corn husk, chitin and chitosan at pH 2.0. Only the chitosan was dissolved at pH 0.5 and a gel was formed. The models of pseudo-second order and external film diffusion described the kinetics of adsorption of Mo ions on the coir. This work showed that the studied biomass has high potential to be used as biosorbent of molybdenum ions from acidic wastewater, and the kinetics of Mo adsorption on the coir suggested high-affinity adsorption governed by chemisorption. (author)

  6. Biomass as biosorbent for molybdenum ions

    International Nuclear Information System (INIS)

    Yamaura, Mitiko; Santos, Jacinete L. dos; Damasceno, Marcos O.; Egute, Nayara dos S.; Moraes, Adeniane A.N.; Santos, Bruno Z.

    2013-01-01

    Biosorbents have been focused as renewable materials of low cost, and have been used for metal removal from the wastewater by adsorption phenomenon. Biosorbents are prepared of biomass, whose reactive sites in its chemical structure have affinity to bind to metal ions. In this work, performance of corn husk, sugarcane bagasse, coir, banana peel, fish scale, chitin and chitosan as biosorbents of molybdenum (VI) ions in aqueous medium was evaluated. The adsorption experiments were investigated in a batch system varying the pH solution from 0.5 to 12 and the contact time between the phases from 2 min to 70 min. 99 Mo radioisotope was used as radioactive tracer for analysis of molybdenum ions by gamma spectroscopy using a HPGe detector. Results revealed that acidity of the solution favored the adsorption of Mo (VI) ions on the all biosorbents. Adsorption values higher than 85% were found on sugarcane bagasse, coir, corn husk, chitin and chitosan at pH 2.0. Only the chitosan was dissolved at pH 0.5 and a gel was formed. The models of pseudo-second order and external film diffusion described the kinetics of adsorption of Mo ions on the coir. This work showed that the studied biomass has high potential to be used as biosorbent of molybdenum ions from acidic wastewater, and the kinetics of Mo adsorption on the coir suggested high-affinity adsorption governed by chemisorption. (author)

  7. Preparation of single phase molybdenum boride

    International Nuclear Information System (INIS)

    Camurlu, Hasan Erdem

    2011-01-01

    Highlights: → Formation of Mo and a mixture of molybdenum boride phases take place in preparation of molybdenum borides. → It is intricate to prepare single phase molybdenum borides. → Formation of single phase MoB from MoO 3 + B 2 O 3 + Mg mixtures has not been reported previously. → Single phase MoB was successfully prepared through a combination of mechanochemical synthesis and annealing process. - Abstract: The formation of MoB through volume combustion synthesis (VCS), and through mechanochemical synthesis (MCS) followed by annealing has been investigated. MoO 3 , B 2 O 3 and Mg were used as reactants while MgO and NaCl were introduced as diluents. Products were leached in dilute HCl solution and were subjected to X-ray diffraction (XRD) analysis and scanning electron microscopy (SEM) examinations. Mo was the major phase component in the VCS products under all the experimental conditions. Mo 2 B, MoB, MoB 2 and Mo 2 B 5 were found as minor phases. Products of MCS contained a mixture of Mo 2 B, MoB, MoB 2 and Mo. After annealing the MCS product at 1400 deg. C for 3 h, single phase α-MoB was obtained.

  8. A solvent extraction study of molybdenum chloride and molybdenum thiocyanate complexes

    Science.gov (United States)

    Greenland, L.P.; Lillie, E.G.

    1974-01-01

    The effect of reducing agents on molybdenum(VI) solutions in hydrochloric acid was studied by a solvent extraction technique to elucidate the composition of the colored molybdenum thiocyanate complex. Neither copper(I) chloride nor ascorbic acid have any effect on the extraction of MoO2Cl2; it is inferred that tin(II) chloride reduces Mo(VI) stepwise to a polynuclear Mo(V)??Mo(VI) complex and then to Mo(V). The colored thiocyanate complex produced by copper(I) and by ascorbic acid differs only slightly in extraction characteristics from the uncolored Mo(VI) complex. It is suggested that the color may be produced by an isomerization reaction of MoO2(SCN)2, and thus that the colored species may be a hexavalent rather than pentavalent molybdenum complex. ?? 1974.

  9. Prospects and adilities of molybdenum leaching from sulfide ores

    International Nuclear Information System (INIS)

    Spivak, A.A.; Korostyshevskij, N.B.; Yudin, I.M.; Lavrenchuk, V.I.; Fridman, I.V.

    1988-01-01

    The conditions and possibilities of using the technology of solution mining during exploration of molybdenum deposits are studied. The possible reacting agents for molybdenum dissolving are studied. Alkali solutions of sodium hypochlorite characterized by high selectivity to molybdenum, activity at low temperatures, simple regeneration by the electrolytic method are considered optimum for technology. Spraying regimes providing favorable sorption conditions are selected. VP-1-P, VP-14K and AM-2B anionites proved to be the best sorbents. The flowsheet of molybdenum ore leaching providing for the preparation of a high-quality industrial product in the form of ammonium paramolybdate is recommended for industrial tests

  10. Sorption of molybdenum by cellulose polyphosphate from acid solutions

    International Nuclear Information System (INIS)

    Luneva, N.K.; Oputina, A.G.; Ermolenko, I.N.

    1985-01-01

    The sorption of molybdenum on cellulose polyphosphate from acid solutions of ammonium molybdate depending on the phosphorus content in samples, concentration and pH of the solution, sorption time is studied. It is shown that a maximum molybdenum content on the cellulose samples with different phosphorus content is pointed out at an ammonium molybdate concentration 0.02 M. Saturation of the sorption curve is attained at molar ratio of adsrbed molybdenum to phosphorus 1:4. In case of small fillings the compound with molybdenum to phosphorus ratio 1:10 is formed

  11. 1.06 μm 150 psec laser damage study of diamond turned, diamond turned/polished and polished metal mirrors

    International Nuclear Information System (INIS)

    Saito, T.T.; Milam, D.; Baker, P.; Murphy, G.

    1975-01-01

    Using a well characterized 1.06 μm 150 ps glass laser pulse the damage characteristics for diamond turned, diamond turned/ polished, and polished copper and silver mirrors less than 5 cm diameter were studied. Although most samples were tested with a normal angle of incidence, some were tested at 45 0 with different linear polarization showing an increase in damage threshold for S polarization. Different damage mechanisms observed will be discussed. Laser damage is related to residual surface influences of the fabrication process. First attempts to polish diamond turned surfaces resulted in a significant decrease in laser damage threshold. The importance of including the heat of fusion in the one dimensional heat analysis of the theoretical damage threshold and how close the samples came to the theoretical damage threshold is discussed. (auth)

  12. Atom probe study of grain boundary segregation in technically pure molybdenum

    International Nuclear Information System (INIS)

    Babinsky, K.; Weidow, J.; Knabl, W.; Lorich, A.; Leitner, H.; Primig, S.

    2014-01-01

    Molybdenum, a metal with excellent physical, chemical and high-temperature properties, is an interesting material for applications in lighting-technology, high performance electronics, high temperature furnace construction and coating technology. However, its applicability as a structural material is limited because of the poor oxidation resistance at high temperatures and a brittle-to-ductile transition around room temperature, which is influenced by the grain size and the content of interstitial impurities at the grain boundaries. Due to the progress of the powder metallurgical production during the last decades, the amount of impurities in the current quality of molybdenum has become so small that surface sensitive techniques are not applicable anymore. Therefore, the atom probe, which allows the detection of small amounts of impurities as well as their location, seems to be a more suitable technique. However, a site-specific specimen preparation procedure for grain boundaries in refractory metals with a dual focused ion beam/scanning electron microscope is still required. The present investigation describes the development and successful application of such a site-specific preparation technique for grain boundaries in molybdenum, which is significantly improved by a combination with transmission electron microscopy. This complimentary technique helps to improve the visibility of grain boundaries during the last preparation steps and to evidence the presence of grain and subgrain boundaries without segregants in atom probe specimens. Furthermore, in industrially processed and recrystallized molybdenum sheets grain boundary segregation of oxygen, nitrogen and potassium is successfully detected close to segregated regions which are believed to be former sinter pores. - Highlights: • First study of grain boundary segregation in molybdenum by atom probe • Site-specific preparation technique by FIB and TEM successfully developed • Grain boundary segregation of

  13. Corporate Politics on Polish Millennials

    Directory of Open Access Journals (Sweden)

    Natalia Roślik

    2017-12-01

    Full Text Available In the very beginning of this particular paper, an author is trying to determine and describe who Millennials actually are. Then, the basis of Millennials definition is analysing corporation’s activity over the past years regarding this age group. The main goal of the thesis is to bring their specific futures out and describe what corporations on Polish job market are doing to encourage them to work in their offices. Especially in Poland within the last years, it is observed that big multinational companies are paying special attention to Millennials and trying to hire them before competitors will do so. As a part of this paper, an author will describe corporate politics and practices on Thomson Reuters and BNY Mellon examples. Within this work, an author is also discussing key features and differences between this generation and Millennials parent’s generation. Additionally, there is a reference to corporate social responsibility concept and work-life balance issues.

  14. Preparation and characterization of some antimonates as ion exchangers and their application sorption of molybdenum from nitric acid solutions

    International Nuclear Information System (INIS)

    El-Naggar, I.M.; Mowafy, E.A.; Ibrahim, G.M.

    2000-01-01

    Various antimonate compounds are well known as important inorganic ion exchangers, since they have radiation stabilities and also high selectivities towards different cations. Ceric, silicon and ferric antimonates were prepared in our laboratories. Characterization of these materials has been described using different techniques, including thermal analysis, surface area measurements, X-ray diffraction and Ir-spectroscopy. The selectivities of these exchangers towards molybdenum have measured under different conditions and a comparison between them had been conducted to enable the suitable exchanger that can be used in the separation of molybdenum from fission products

  15. On the effect of interaction of molybdenum trioxide and magnesium oxide in water

    International Nuclear Information System (INIS)

    Bunin, V.M.; Karelin, A.I.; Solov'eva, L.N.

    1992-01-01

    Interaction of molybdenum trioxide and magnesium oxide in water was studied. It is shown that molybdenum trioxide forms consecutively magnesium molybdate, dimolybdate and magnesium polymolybdates with magnesium oxide

  16. Smoking characteristics of Polish immigrants in Dublin

    Directory of Open Access Journals (Sweden)

    Zatonski Witold

    2008-12-01

    Full Text Available Abstract Background This study examined two main hypotheses: a Polish immigrants' smoking estimates are greater than their Irish counterparts (b Polish immigrants purchasing cigarettes from Poland smoke "heavier" (≥ 20 cigarettes a day when compared to those purchasing cigarettes from Ireland. The study also set out to identify significant predictors of 'current' smoking (some days and everyday among the Polish immigrants. Methods Dublin residents of Polish origin (n = 1,545 completed a previously validated Polish questionnaire in response to an advertisement in a local Polish lifestyle magazine over 5 weekends (July–August, 2007. The Office of Tobacco Control telephone-based monthly survey data were analyzed for the Irish population in Dublin for the same period (n = 484. Results Age-sex adjusted smoking estimates were: 47.6% (95% Confidence Interval [CI]: 47.3%; 48.0% among the Poles and 27.8% (95% CI: 27.2%; 28.4% among the general Irish population (p 24 months were significant predictors of current smoking among the Poles. An objective validation of the self-reported smoking history of a randomly selected sub-sample immigrant group, using expired carbon monoxide (CO measurements, showed a highly significant correlation coefficient (r = 0.64 of expired CO levels with the reported number of cigarettes consumed (p Conclusion Polish immigrants' smoking estimates are higher than their Irish counterparts, and particularly if employed, with only primary-level education, and are overseas >2 years.

  17. Effect of Clinically Relevant CAD/CAM Zirconia Polishing on Gingival Fibroblast Proliferation and Focal Adhesions

    Directory of Open Access Journals (Sweden)

    Nicholas G. Fischer

    2017-11-01

    Full Text Available Mucosal seal formation around dental abutments is critical to the successful integration of dental implants into the human oral cavity. No information exists for how clinically relevant polishing procedures for computer-aided design and computer-aided manufactured (CAD/CAM zirconia abutments affects cellular responses important to mucosal seal formation. CAD/CAM zirconia was divided into four groups for clinically relevant polishing utilizing commercial polishing heads: control, coarse, coarse plus medium, and coarse plus medium plus fine. Surfaces were analyzed with scanning electron microscopy (SEM, atomic force microscopy (AFM, and optical profilometry (OP. Subsequently, human gingival fibroblasts (HGFs were seeded onto the zirconia surfaces. Proliferation was measured via a quantitative SEM technique and focal adhesion kinase (FAK phosphorylation status was measured by an enzyme-linked immunosorbent assay (ELISA. Results showed an increase in proliferation on all polished surfaces as compared to the control. Phosphorylation of FAK at tyrosine 397 (Y397 was up-modulated on the control surfaces. The associated cell adaptation is discussed. In all cases, FAK phosphorylation was greater at 24 h than 48 h. These results suggest that clinicians should be mindful of the effects of abutment polishing methodology, as this may have an impact on early mucosal seal formation.

  18. Molybdenum carbide-carbon nanocomposites synthesized from a reactive template for electrochemical hydrogen evolution

    KAUST Repository

    Alhajri, Nawal Saad

    2014-01-01

    Molybdenum carbide nanocrystals (Mo2C) with sizes ranging from 3 to 20 nm were synthesized within a carbon matrix starting from a mesoporous graphitic carbon nitride (mpg-C3N4) template with confined pores. A molybdenum carbide phase (Mo2C) with a hexagonal structure was formed using a novel synthetic method involving the reaction of a molybdenum precursor with the carbon residue originating from C3N4 under nitrogen at various temperatures. The synthesized nanocomposites were characterized using powder X-ray diffraction (XRD), temperature-programmed reaction with mass spectroscopy (MS), CHN elemental analyses, thermogravimetric analyses (TGA), nitrogen sorption, X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM). The results indicated that the synthesized samples have different surface structures and compositions, which are accordingly expected to exhibit different electrocatalytic activities toward the hydrogen evolution reaction (HER). Electrochemical measurements demonstrated that the sample synthesized at 1323 K exhibited the highest and most stable HER current in acidic media, with an onset potential of -100 mV vs. RHE, among the samples prepared in this study. This result is attributed to the sufficiently small particle size (∼8 nm on average) and accordingly high surface area (308 m2 g-1), with less oxidized surface entrapped within the graphitized carbon matrix. © 2014 the Partner Organisations.

  19. Preparation and Evaluation of a Polyimide-Coated Ultrafine Gilt Molybdenum Wire and Its Knitted Mesh Used for Electromagnetic Reflectors

    Directory of Open Access Journals (Sweden)

    Huiqi Shao

    2017-12-01

    Full Text Available In this work, polyimide (PI was coated onto an ultrafine gilt molybdenum wire in order to protect the gilt surface and prepare an electrically stable wire mesh material which can be widely used in space. The surface of the PI-coated gilt molybdenum wires was characterized using FTIR, SEM, and EDS. Factors such as temperature stability of the PI coating, mechanical properties of the PI-coated gilt molybdenum wires, contact resistance stability, and electromagnetic microwave reflectivity of the their knitted meshes were also investigated. The results indicate that the PI coating conformed uniformly to the surface of the gilt molybdenum wires. The prepared PI coating exhibited excellent temperature stability in the −196 to 300 °C range and could efficiently protect the gilt surface and improve the stability of contact resistance, while the reflection of its wire meshes showed only a slight decrease of 1.4% with the PI coating thickness of 3 μm for electromagnetic microwaves in the S band.

  20. Chemical mechanical polishing of tantalum and tantalum nitride

    Science.gov (United States)

    Janjam, Sathish Babu S. V.

    There is a continuing need in the semiconductor industry to clear residual copper (Cu) and planarize the tantalum (Ta)/tantalum nitride (TaN) barrier/etch stop layer with a higher removal rate using the technique of Chemical Mechanical Polishing (CMP). Obtaining high removal rates for Ta/TaN is very challenging as the films are very hard, and hence it is difficult to achieve high Ta/TaN removal rates by just relying on an increase in the mechanical forces (operating pressure) alone during CMP. Ta/TaN is an inert metal, therefore, obtaining high Ta/TaN removal rates by using chemical additives is also challenging. Not only Ta/TaN needs to be removed at a higher rate in the second step of polishing, but also remaining Cu should be cleared. It is important to search for novel chemicals that can form a thin film on the Ta/TaN surface which can be easily abraded by the polishing pad with very less pressure. In this work, oxalic and tartaric acids have been investigated as the complexing agents in slurries for Ta/TaN CMP. Oxalic and tartaric acids appear to be reactive with Ta in the presence of hydrogen peroxide. A dispersion of the Oxalic acid (OA)/Tartaric Acid (TA) - peroxide mixtures with silica (fumed/colloidal) can be used to achieve Ta removal rates that are ˜ 90 nm/min at pH between 3 to 6 by applying a down force of 6.3 psi, where as at a lower down force of 2 psi, a removal rate of ˜ 40 nm/min has been achieved at pH = 3. It was shown earlier that a high Cu removal rate can be obtained using OA-peroxide based slurries with/without the addition of abrasives at pH = 3 [1]. So, in the first step, Cu could be removed at high rates at pH = 3 and by changing the pH to 5 or 6, Ta/TaN can be removed as mentioned above. Hence these slurries could be used as "single dispersion slurries " that could be used for both the first and second steps of Cu CMP. During the second step (barrier layer polish), Cu removal rates are low but not low enough to minimize dishing with

  1. Effect of finishing and polishing on the color stability of a composite resin immersed in staining solutions

    Directory of Open Access Journals (Sweden)

    Maiara Justo Polli

    2015-01-01

    Full Text Available Objective: To evaluate the influence of finishing/polishing methods and staining solutions using different immersion periods on the color stability of a microhybrid composite resin. Materials and Methods: Ninety specimens were fabricated using a stainless steel mold and polyester strips. The samples were randomly divided into five groups according to the finishing and polishing performed: Control group (no surface treatment was performed, Diamond Pro group, Diamond burs group, Enhance group, and SiC paper group. After finishing and polishing, six samples from each group were immersed in coffee, red wine, or water for 30 days. The color measurements were obtained using digital photography before immersion and after 7, 15, and 30 days of immersion. The red, green, and blue values provided by the Adobe Photoshop software were converted into CIELab values. A three-way analysis of variance and Tukey's test were used for statistical analysis (P ≤ 0.05. Results: The finishing and polishing methods, staining solutions, immersion times, and their interaction had statistically significant effects on the color change (P = 0.00. Coffee and red wine caused intense staining. Among the polishing methods, the highest color change value was observed in the control group (P < 0.05 and the Diamond Pro disks provided the most stain-resistant surfaces (P ≤ 0.05. Conclusion: The finishing and polishing method, staining solution, and immersion time influences the color stability. Finishing and polishing should be applied to obtain a more stain-resistant surface.

  2. Extraction and determination of molybdenum with tributyl phosphate Application to analysis of copper-molybdenum ores.

    Science.gov (United States)

    Caiozzi, M; Zunino, H; Sepúlveda, L

    1969-12-01

    A differential spectrophotometric method is described for the determination of molybdenum by means of solvent extraction with tributylphosphate of the peroxymolybdate complex formed with H(2)O(2) in 3.5N H(2)SO(4). The extraction parameters are studied, and the behaviour of some other ions is reported. The method is used for ore analysis.

  3. Thermal outgassing studies on machinable tungsten and TZM molybdenum alloy

    International Nuclear Information System (INIS)

    Liu, C.; Nielsen, R.W.; Li, Y.; Ryding, D.; Kuzay, T.M.

    1994-01-01

    Machinable tungsten and molybdenum alloys are extensively used as safety shutters and optical slits at the Advanced Photon Source (APS) front ends. These materials may present a vacuum problem because of their porosity. Also, an environmentally hazard-free cleaning procedure has to be developed for these materials. We have chosen specially heat-treated machinable tungsten with a density of 18 g/cm 3 for safety shutters and TZM (a molybdenum alloy containing 0.5% titanium and ∼0.1% zirconium) for optical slits. Thermal outgassing tests have been performed for a machinable tungsten set with a total surface area of 4500 cm 2 and a 2.8 x 4.6 x 32.6 cm 3 piece of TZM. A cleaning procedure using alkaline detergent ultrasonic washes and vacuum furnace baking was used before outgassing measurements. Outgassing rates 10 hours after initial pump down at room temperature are 1.6 x 10 -10 Torr·l·s -1 ·cm -2 for machinable tungsten and 6.0 x 10 -10 Torr·l·s -1 ·cm -2 for TZM. The outgassing rates 24 hours after an in situ bake at 160 degrees C for two days decreased to 2.2 x 10 -12 Torr·l·s -1 ·cm -2 for machinable tungsten and 2.2 x 10 -11 Torr·l·s -1 · -2 for TZM. Optical studies confirmed that the TZM sample is more porous than the machinable tungsten sample. Further studies of a denser TZM sample show that the outgassing rate decreases as the porosity decreases. The outgassing rate 24 hours after a 48-h bake at 160 degree C reached 7.4 x 10 -12 Torr·l·s -1 ·cm -2 for the denser TZM sample

  4. Soil organic matter regulates molybdenum storage and mobility in forests

    Science.gov (United States)

    Marks, Jade A; Perakis, Steven; King, Elizabeth K.; Pett-Ridge, Julie

    2015-01-01

    The trace element molybdenum (Mo) is essential to a suite of nitrogen (N) cycling processes in ecosystems, but there is limited information on its distribution within soils and relationship to plant and bedrock pools. We examined soil, bedrock, and plant Mo variation across 24 forests spanning wide soil pH gradients on both basaltic and sedimentary lithologies in the Oregon Coast Range. We found that the oxidizable organic fraction of surface mineral soil accounted for an average of 33 %of bulk soil Mo across all sites, followed by 1.4 % associated with reducible Fe, Al, and Mn-oxides, and 1.4 % in exchangeable ion form. Exchangeable Mo was greatest at low pH, and its positive correlation with soil carbon (C) suggests organic matter as the source of readily exchangeable Mo. Molybdenum accumulation integrated over soil profiles to 1 m depth (τMoNb) increased with soil C, indicating that soil organic matter regulates long-term Mo retention and loss from soil. Foliar Mo concentrations displayed no relationship with bulk soil Mo, and were not correlated with organic horizon Mo or soil extractable Mo, suggesting active plant regulation of Mo uptake and/or poor fidelity of extractable pools to bioavailability. We estimate from precipitation sampling that atmospheric deposition supplies, on average, over 10 times more Mo annually than does litterfall to soil. In contrast, bedrock lithology had negligible effects on foliar and soil Mo concentrations and on Mo distribution among soil fractions. We conclude that atmospheric inputs may be a significant source of Mo to forest ecosystems, and that strong Mo retention by soil organic matter limits ecosystem Mo loss via dissolution and leaching pathways.

  5. Molybdenum isotope fractionation during adsorption to organic matter

    Science.gov (United States)

    King, Elizabeth K.; Perakis, Steven; Pett-Ridge, Julie C.

    2018-01-01

    Organic matter is of emerging interest as a control on molybdenum (Mo) biogeochemistry, and information on isotope fractionation during adsorption to organic matter can improve interpretations of Mo isotope variations in natural settings. Molybdenum isotope fractionation was investigated during adsorption onto insolubilized humic acid (IHA), a surrogate for organic matter, as a function of time (2–170 h) and pH (2–7). For the time series experiment performed at pH 4.2, the average Mo isotope fractionation between the solution and the IHA (Δ98Mosolution-IHA) was 1.39‰ (± 0.16‰, 2σ, based on 98Mo/95Mo relative to the NIST 3134 standard) at steady state. For the pH series experiment, Mo adsorption decreased as pH increased from 2.0 to 6.9, and the Δ98Mosolution-IHA increased from 0.82‰ to 1.79‰. We also evaluated natural Mo isotope patterns in precipitation, foliage, organic horizon, surface mineral soil, and bedrock from 12 forested sites in the Oregon Coast Range. The average Mo isotope offset observed between precipitation and organic (O) horizon soil was 2.1‰, with light Mo isotopes adsorbing preferentially to organic matter. Fractionation during adsorption to organic matter is similar in magnitude and direction to prior observations of Mo fractionation during adsorption to Fe- and Mn- (oxyhydr)oxides. Our finding that organic matter influences Mo isotope composition has important implications for the role of organic matter as a driver of trace metal retention and isotopic fractionation.

  6. Comparative study of performance of shoe polishes formulated from ...

    African Journals Online (AJOL)

    GARZALI

    This should make the polish remains as discrete solid particles held mechanically within the leather. This work intends to explore the use of polyethylene pigment in the production of shoe polish. The shoe polish produced will be applied alongside shoe polish from carbon black (CI black Pigment 7) on finished black leather ...

  7. Nd:YOV4 laser polishing on WC-Co HVOF coating

    Science.gov (United States)

    Giorleo, L.; Ceretti, E.; Montesano, L.; La Vecchia, G. M.

    2017-10-01

    WC/Co coatings are widely applied to different types of components due to their extraordinary performance properties including high hardness and wear properties. In industrial applications High Velocity Oxy-Fuel (HVOF) technique is extensively used to deposit hard metal coatings. The main advantage of HVOF compared to other thermal spray techniques is the ability to accelerate the melted powder particles of the feedstock material at a relatively high velocity, leading to obtain good adhesion and low porosity level. However, despite the mentioned benefits, the surface finish quality of WC-Co HVOF coatings results to be poor (Ra higher than 5 µm) thus a mechanical polishing process is often needed. The main problem is that the high hardness of coating leads the polishing process expensive in terms of time and tool wear; moreover polishing becomes difficult and not always possible in case of limited accessibility of a part, micro dimensions or undercuts. Nowadays a different technique available to improve surface roughness is the laser polishing process. The polishing principle is based on focused radiation of a laser beam that melts a microscopic layer of surface material. Compared to conventional polishing process (as grinding) it ensures the possibility of avoiding tool wear, less pollution (no abrasive or liquids), no debris, less machining time and coupled with a galvo system it results to be more suitable in case of 3D complex workpieces. In this paper laser polishing process executed with a Nd:YOV4 Laser was investigated: the effect of different process parameters as initial coating morphology, laser scan speed and loop cycles were tested. Results were compared by a statistical approach in terms of average roughness along with a morphological analysis carried out by Scanning Electron Microscope (SEM) investigation coupled with EDS spectra.

  8. The Effect of Molybdenum Fertilization on Arachis Glabrata Biomass ...

    African Journals Online (AJOL)

    The effect of molybdenum fertilization on biomass and the number of nodules of Arachis glabrata was assessed at the Teaching and Research Farm of the University of Dschang in 2011 at different periods of mowing. A factorial design comparing four doses of molybdenum as ammonium molybdate (0, 0.75, 1.5 and 2.25 ...

  9. Low-temperature heat capacity of molybdenum borides

    International Nuclear Information System (INIS)

    Bolgar, A.S.; Klinder, A.V.; Novoseletskaya, L.M.; Turov, V.P.; Klochkov, L.A.; Lyashchenko, A.B.

    1988-01-01

    Heat capacity of molybdenum borides Mo 2 B, MoB, Mo 2 B 5 is studied for the first time in the 60-300 K range using the adiabatic method. Standard (at 298.15 K) thermodynamic functions (enthalpy, heat capacity, entropy, reduced Gibbs energy) of molybdenum borides are calculated

  10. Tetrathionate reductase of Salmonella thyphimurium: a molybdenum containing enzyme

    International Nuclear Information System (INIS)

    Hinojosa-Leon, M.; Dubourdieu, M.; Sanchez-Crispin, J.A.; Chippaux, M.

    1986-01-01

    Use of radioactive molybdenum demonstrates that the tetrathionate reductase of Salmonella typhimurium is a molydenum containing enzyme. It is proposed that this enzyme shares with other molybdo-proteins, such as nitrate reductase, a common molybdenum containing cofactor the defect of which leads to the loss of the tetrathionate reductase and nitrate reductase activities

  11. Abrasive wear of resin composites as related to finishing and polishing procedures.

    Science.gov (United States)

    Turssi, Cecilia P; Ferracane, Jack L; Serra, Mônica C

    2005-07-01

    Finishing and polishing procedures may cause topographical changes and introduce subsurface microcracks in dental composite restoratives. Since both of these effects may contribute toward the kinetics of wear, the purpose of this study was to assess and correlate the wear and surface roughness of minifilled and nanofilled composites finished and polished by different methods. Specimens (n=10) made of a minifilled and a nanofilled composite were finished and polished with one of the four sequences: (1) tungsten carbide burs plus Al(2)O(3)-impregnated brush (CbBr) or (2) tungsten carbide burs plus diamond-impregnated cup (CbCp), (3) diamond burs plus brush (DmBr) or (4) diamond burs plus cup (DmCp). As a control, abrasive papers were used. After surface roughness had been quantified, three-body abrasion was simulated using the OHSU wear machine. The wear facets were then scanned to measure wear depth and post-testing roughness. All sets of data were subjected to ANOVA and Tukey's tests (alpha=0.05). Pearson's correlation test was applied to check for the existence of a relationship between pre-testing roughness and wear. Significantly smoother surfaces were attained with the sequences CbBr and CbCp, whereas DmCp yielded the roughest surface. Regardless of the finishing/polishing technique, the nanofilled composite exhibited the lowest pre-testing roughness and wear. There was no correlation between the surface roughness achieved after finishing/polishing procedures and wear (p=0.3899). Nano-sized materials may have improved abrasive wear resistance over minifilled composites. The absence of correlation between wear and surface roughness produced by different finishing/polishing methods suggests that the latter negligibly influences material loss due to three-body abrasion.

  12. Kinetics of Molybdenum Reduction to Molybdenum Blue by Bacillus sp. Strain A.rzi

    Directory of Open Access Journals (Sweden)

    A. R. Othman

    2013-01-01

    Full Text Available Molybdenum is very toxic to agricultural animals. Mo-reducing bacterium can be used to immobilize soluble molybdenum to insoluble forms, reducing its toxicity in the process. In this work the isolation of a novel molybdate-reducing Gram positive bacterium tentatively identified as Bacillus sp. strain A.rzi from a metal-contaminated soil is reported. The cellular reduction of molybdate to molybdenum blue occurred optimally at 4 mM phosphate, using 1% (w/v glucose, 50 mM molybdate, between 28 and 30°C and at pH 7.3. The spectrum of the Mo-blue product showed a maximum peak at 865 nm and a shoulder at 700 nm. Inhibitors of bacterial electron transport system (ETS such as rotenone, sodium azide, antimycin A, and potassium cyanide could not inhibit the molybdenum-reducing activity. At 0.1 mM, mercury, copper, cadmium, arsenic, lead, chromium, cobalt, and zinc showed strong inhibition on molybdate reduction by crude enzyme. The best model that fitted the experimental data well was Luong followed by Haldane and Monod. The calculated value for Luong’s constants pmax, Ks, Sm, and n was 5.88 μmole Mo-blue hr−1, 70.36 mM, 108.22 mM, and 0.74, respectively. The characteristics of this bacterium make it an ideal tool for bioremediation of molybdenum pollution.

  13. Molybdenum Dichalcogenides for Environmental Chemical Sensing

    Directory of Open Access Journals (Sweden)

    Dario Zappa

    2017-12-01

    Full Text Available 2D transition metal dichalcogenides are attracting a strong interest following the popularity of graphene and other carbon-based materials. In the field of chemical sensors, they offer some interesting features that could potentially overcome the limitation of graphene and metal oxides, such as the possibility of operating at room temperature. Molybdenum-based dichalcogenides in particular are among the most studied materials, thanks to their facile preparation techniques and promising performances. The present review summarizes the advances in the exploitation of these MoX2 materials as chemical sensors for the detection of typical environmental pollutants, such as NO2, NH3, CO and volatile organic compounds.

  14. Molybdenum applications in the electronics market

    Science.gov (United States)

    Shields, John A.; Lipetzky, Pete

    2000-03-01

    Molybdenum’s role in the electronics market has been an important one since the earliest days of vacuum tubes. Common electronic applications include components used to manufacture electrical devices, including setter tiles for sintering ceramic substrates and multilayer ceramic circuits, as well as physical-vapor deposition masks. Molybdenum is also used for thermal-management applications when paired with copper and is a necessary part of high-power diodes and rectifiers as well as field-emitter components in flat-panel displays.

  15. Hot rolling of thick uranium molybdenum alloys

    Science.gov (United States)

    DeMint, Amy L.; Gooch, Jack G.

    2015-11-17

    Disclosed herein are processes for hot rolling billets of uranium that have been alloyed with about ten weight percent molybdenum to produce cold-rollable sheets that are about one hundred mils thick. In certain embodiments, the billets have a thickness of about 7/8 inch or greater. Disclosed processes typically involve a rolling schedule that includes a light rolling pass and at least one medium rolling pass. Processes may also include reheating the rolling stock and using one or more heavy rolling passes, and may include an annealing step.

  16. Single-layer Molybdenum disulfide photodetectors

    OpenAIRE

    López Sánchez, Oriol

    2012-01-01

    Projecte realitzat mitjançant programa de mobilitat. École polytechnique fédérale de Lausanne [ANGLÈS] Two-dimensional (2D) materials are very attractive candidates for use in next-generation nanoelectronic devices. Compared to one-dimensional materials, with 2D materials is relatively easy to fabricate complex structures. 2D materials, such as molybdenum disulfide (MoS2), have attracted increasing attention for their electronic and optoelectronic particular properties and size. MoS2 is a...

  17. Electrochemical ammonia production on molybdenum nitride nanoclusters

    DEFF Research Database (Denmark)

    Howalt, Jakob Geelmuyden; Vegge, Tejs

    2013-01-01

    Theoretical investigations of electrochemical production of ammonia at ambient temperature and pressure on nitrogen covered molybdenum nanoparticles are presented. Density functional theory calculations are used in combination with the computational hydrogen electrode approach to calculate the free...... energy profile for electrochemical protonation of N2 and N adatoms on cuboctahedral Mo13 nanoparticles. Pathways for electrochemical ammonia production via direct protonation of N adatoms and N2 admolecules with an onset potential as low as -0.5 V and generally lower than -0.8 V on both a nitrogen...

  18. Investigation of iron-bismuth-molybdenum catalysts

    International Nuclear Information System (INIS)

    Ven'yaminov, S.A.; Barannik, G.B.; Pitaeva, A.N.; Sazonova, N.N.; Plyasova, L.M.

    1977-01-01

    The catalytic properties of an oxide iron-bismuth-molybdenum system in reactions of oxidative ammonolysis of propylene and oxidative dehydrogenation of butene-1 are investigated. It is shown that catalysts containing double molybdate of bismuth and iron (the X-phase) exhibit an increased catalytic activity as compared with bismuth molybdate (Bi 2 O 3 x3MoO 3 ). Preliminary reduction of such specimens increases their activity and selectivity in subsequent work under conditions of a stationary course of the oxidation reaction. The activity and selectivity of catalysts containing only bismuth molybdate and iron molybdate are due to the additivity of the properties of the separate molybdates

  19. New Environmental Practices in Polish Production Firms

    DEFF Research Database (Denmark)

    Kræmer, Trine Pipi

    2002-01-01

    Based on five case studies in Poland, the paper discusses, how a specific environmental policy influences the firms? industrial environmental practices. The study illustrates, how the Polish environmental policy, dominated by environmental charges on emissions, is extremely effective in improving...

  20. Electro Polishing of Niobium Cavities at DESY

    CERN Document Server

    Matheisen, A; Morales, H; Petersen, B; Schmoekel, M; Steinhau-Kühl, N

    2004-01-01

    At DESY a facility for electro polishing (EP) of the super conducting (s.c.) TESLA/TTF cavities have been built and is operational since summer 2003. The EP infrastructure is capable to handle single-cell structures and the standard TESLA/ TTF nine-cell cavities. Several electro polishing processes have been made since and acceleration voltage up to 40 MV/m have been reached in nine cell structures. We report on measurements and experiences gained since 2003 as well as on handling procedures developed for the preparation of electro polished resonators. Specific data like heat production, variation of current density and bath aging will be presented. Another important point for reproducible results is the quality control of the electro polishing process. First quality control steps to be implanted in the EP procedure for large-scale production will be described.

  1. Semiological analysis of Polish theater posters

    Directory of Open Access Journals (Sweden)

    Jelena Nikolić

    2016-02-01

    Full Text Available Through the application of semiological analysis to theater posters made by two Polish authors, the paper uncovers signs, meanings, codes and specifics of the „Polish school of poster-making“ and contemporary Polish posters. Aside from this, I suggest a methodological framework for studying the issue of coding and shaping a theater poster as a culturally specific form of visual communication. The aesthetic and semiotic outlook of the Polish theater posters which were chosen is analyzed using the semiological method which highlights their differences and similarities. By pointing out the system of codes through the examples given here, a graphic designer is informed about the existence and the possibilities of a more systematic approach to shaping a theater poster.

  2. Report on Polish Public Libraries 2001

    OpenAIRE

    Bednarek-Michalska, Bożena; Szatkowska, Olga

    2001-01-01

    Report is an overview of polish public libraries, services to a variety of communities, it also provides statistics, n explanation of the funding policy for public libraries in Poland and information about the governance of public libraries in the country.

  3. Solid solutions of hydrogen in niobium, molybdenum and their alloys

    International Nuclear Information System (INIS)

    Ishikawa, T.T.

    1981-01-01

    The solubility of hydrogen in niobium, molybdenum and niobium-molybdenum alloys with varying atomic fraction of molybdenum from 0.15 to 0.75 was measured on the temperature range of 673 0 K to 1273 0 k for one atmosphere hydrogen pressure. The experimental technique involved the saturation of the solvent metal or alloy with hydrogen, followed by quenching and analysis of the solid solution. The results obtained of hydrogen solubility are consistent with the quasi-regular model for the dilute interstitial solid solutions. The partial molar enthalpy and partial molar entropy in excess of the dissolved hydrogen atoms were calculated from data of solubility versus reciprocal doping temperature. The variation of the relative partial molar enthalpy of hydrogen dissolved in niobium-molybdenum alloys, with the increase of molybdenum content of the alloy was analized. (Author) [pt

  4. Electrolytic polishing system for space age materials

    International Nuclear Information System (INIS)

    Coons, W.C.; Iosty, L.R.

    1976-01-01

    A simple electrolytic polishing technique was developed for preparing Cr, Co, Hf, Mo, Ni, Re, Ti, V, Zr, and their alloys for structural analysis on the optical microscope. The base electrolyte contains 5g ZnCl 2 and 15g AlCl 3 . 6H 2 O in 200 ml methyl alcohol, plus an amount of H 2 SO 4 depending on the metal being polished. Five etchants are listed

  5. Trace element analysis of nail polishes

    International Nuclear Information System (INIS)

    Misra, G.; Mittal, V.K.; Sahota, H.S.

    1999-01-01

    Instrumental neutron activation analysis (INAA) technique was used to measure the concentrations of various trace elements in nail polishes of popular Indian and foreign brands. The aim of the present experiment was to see whether trace elements could distinguish nail polishes of different Indian and foreign brands from forensic point of view. It was found that cesium can act as a marker to differentiate foreign and Indian brands. (author)

  6. Interlocking directorships in Polish joint stock companies:

    OpenAIRE

    Pawlak, Marek

    2008-01-01

    Studies concerning interlocking directorships have been carried out among Polish joint stock corporations. The main source of data have been the announcements that are to be published by corporations regularly in a journal called Business and Court Gazette (BCG). Interlocking directorships constitute a network among corporations the use of which enables co-ordinated management of the whole group. The phenomenon of interlocking directorships in Polish joint stock companies can be compared to t...

  7. Jewish problem in the Polish Communist Party

    Directory of Open Access Journals (Sweden)

    Cimek Henryk

    2016-12-01

    Full Text Available Jews accounted for approx. 8-10% of the population of the Second Republic and in the communist movement (Polish Communist Party and Polish Communist Youth Union the rate was approx, 30%, while in subsequent years it much fluctuated. The percentage of Jews was the highest in the authorities of the party and in the KZMP. This had a negative impact on the position of the KPP on many issues, especially in its relation to the Second Republic.

  8. Experimental Polish-Lithuanian Corpus with the Semantic Annotation Elements

    Directory of Open Access Journals (Sweden)

    Danuta Roszko

    2015-06-01

    Full Text Available Experimental Polish-Lithuanian Corpus with the Semantic Annotation Elements In the article the authors present the experimental Polish-Lithuanian corpus (ECorpPL-LT formed for the idea of Polish-Lithuanian theoretical contrastive studies, a Polish-Lithuanian electronic dictionary, and as help for a sworn translator. The semantic annotation being brought into ECorpPL-LT is extremely useful in Polish-Lithuanian contrastive studies, and also proves helpful in translation work.

  9. Iron binary and ternary coatings with molybdenum and tungsten

    Energy Technology Data Exchange (ETDEWEB)

    Yar-Mukhamedova, Gulmira, E-mail: gulmira-alma-ata@mail.ru [Institute Experimental and Theoretical Physics Al-Farabi Kazakh National University, 050038, Al-Farabi av., 71, Almaty (Kazakhstan); Ved, Maryna; Sakhnenko, Nikolay; Karakurkchi, Anna; Yermolenko, Iryna [National Technical University “Kharkov Polytechnic Institute”, Kharkov (Ukraine)

    2016-10-15

    Highlights: • High quality coatings of double Fe-Mo and ternary Fe-Mo-W electrolytic alloys can be produced both in a dc and a pulsed mode. • Application of unipolar pulsed current allows receiving an increased content of the alloying components and their more uniform distribution over the surface. • It is established that Fe-Mo and Fe-Mo-W coatings have an amorphous structure and exhibit improved corrosion resistance and microhardness as compared with the steel substrate due to the inclusion molybdenum and tungsten. - Abstract: Electrodeposition of Fe-Mo-W and Fe-Mo layers from a citrate solution containing iron(III) on steel and iron substrates is compared. The utilization of iron(III) compounds significantly improved the electrolyte stability eliminating side anodic redox reactions. The influence of concentration ratios and electrodeposition mode on quality, chemical composition, and functional properties of the alloys is determined. It has been found that alloys deposited in pulse mode have more uniform surface morphology and chemical composition and contain less impurities. Improvement in physical and mechanical properties as well as corrosion resistance of Fe-Mo and Fe-Mo-W deposits when compared with main alloy forming metals is driven by alloying components chemical passivity as well as by alloys amorphous structure. Indicated deposits can be considered promising materials in surface hardening technologies and repair of worn out items.

  10. DNA origami deposition on native and passivated molybdenum disulfide substrates

    Directory of Open Access Journals (Sweden)

    Xiaoning Zhang

    2014-04-01

    Full Text Available Maintaining the structural fidelity of DNA origami structures on substrates is a prerequisite for the successful fabrication of hybrid DNA origami/semiconductor-based biomedical sensor devices. Molybdenum disulfide (MoS2 is an ideal substrate for such future sensors due to its exceptional electrical, mechanical and structural properties. In this work, we performed the first investigations into the interaction of DNA origami with the MoS2 surface. In contrast to the structure-preserving interaction of DNA origami with mica, another atomically flat surface, it was observed that DNA origami structures rapidly lose their structural integrity upon interaction with MoS2. In a further series of studies, pyrene and 1-pyrenemethylamine, were evaluated as surface modifications which might mitigate this effect. While both species were found to form adsorption layers on MoS2 via physisorption, 1-pyrenemethylamine serves as a better protective agent and preserves the structures for significantly longer times. These findings will be beneficial for the fabrication of future DNA origami/MoS2 hybrid electronic structures.

  11. Interculutral Polish-Chinese QQing

    Directory of Open Access Journals (Sweden)

    Elżbieta Gajek

    2012-12-01

    Full Text Available Working in tandem with the use of information and communication technologies is well-known and frequently used as a method of supporting learning of foreign languages in authentic communication. It is based on a constructivist approach to teaching. In the reported case study Polish and Chinese students discussed in English preprepared topics. The work shows the potential of e-learning at the micro level, as the language and intercultural task is implemented into an academic course without modification of the objectives and learning outcomes of the course. Evaluation carried out at the end of the project indicates that both groups perceived the task as a significant linguistic, cultural and personal experience. They stressed the importance of sharing “culture for culture” as the partner culture was new for most of them. The ability to talk and respond to information which was often strange, from the point of view of their own culture, allowed for learning intercultural competence ̔in action’.

  12. Comparison of tool feed influence in CNC polishing between a novel circular-random path and other pseudo-random paths.

    Science.gov (United States)

    Takizawa, Ken; Beaucamp, Anthony

    2017-09-18

    A new category of circular pseudo-random paths is proposed in order to suppress repetitive patterns and improve surface waviness on ultra-precision polished surfaces. Random paths in prior research had many corners, therefore deceleration of the polishing tool affected the surface waviness. The new random path can suppress velocity changes of the polishing tool and thus restrict degradation of the surface waviness, making it suitable for applications with stringent mid-spatial-frequency requirements such as photomask blanks for EUV lithography.

  13. Boron modified molybdenum silicide and products

    International Nuclear Information System (INIS)

    Meyer, M.K.; Akinc, M.

    1999-01-01

    A boron-modified molybdenum silicide material is disclosed having the composition comprising about 80 to about 90 weight % Mo, about 10 to about 20 weight % Si, and about 0.1 to about 2 weight % B and a multiphase microstructure including Mo 5 Si 3 phase as at least one microstructural component effective to impart good high temperature creep resistance. The boron-modified molybdenum silicide material is fabricated into such products as electrical components, such as resistors and interconnects, that exhibit oxidation resistance to withstand high temperatures in service in air as a result of electrical power dissipation, electrical resistance heating elements that can withstand high temperatures in service in air and other oxygen-bearing atmospheres and can span greater distances than MoSi 2 heating elements due to improved creep resistance, and high temperature structural members and other fabricated components that can withstand high temperatures in service in air or other oxygen-bearing atmospheres while retaining creep resistance associated with Mo 5 Si 3 for structural integrity. 7 figs

  14. High-strength chromium--molybdenum rails

    International Nuclear Information System (INIS)

    Smith, Y.E.; Sawhill, J.M. Jr.; Cias, W.W.; Eldis, G.T.

    1976-01-01

    A laboratory study was conducted with the aim of developing an as-rolled rail of over 100 ksi (689 N/mm 2 ) yield strength. A series of compositions providing both pearlitic and bainitic microstructures was evaluated. A fine pearlitic structure was developed in a 0.73 percent C -- 0.83 percent Mn -- 0.16 percent Si -- 0.75 percent Cr -- 0.21 percent Mo steel by simulating the mill cooling rate of 132-lb/yd (65.5-kg/m) rail. Two 100-ton commercial heats were made of this approximate composition and processed into 132-lb/yd (65.5-kg/m) rail. Samples tested in the laboratory ranged from 109 to 125 ksi (750 to 860 N/mm 2 ) in yield strength. The chromium-molybdenum rails also exhibited excellent fracture toughness and fatigue properties. Sections of the rail were joined by both flash-butt welding and thermite welding. The hardness peaks produced in the flash-butt welds could be reduced by applying either a postweld current or an induction heating cycle. The high-strength chromium-molybdenum rails have been in service for over eight months in curved sections of an ore railway that carries over 55 million gross long tons per year. 7 tables, 18 figs

  15. Evaluation of the effect of polishing on flexural strength of feldspathic porcelain and its comparison with autoglazing and over glazing

    Directory of Open Access Journals (Sweden)

    Jalali H.

    2005-06-01

    Full Text Available Statement of Problem: Ceramic restorations are popular because they can provide the most natural replacement for teeth. However, the brittleness of ceramics is a primary disadvantage. There are various methods for strengthening ceramics such as metal framework, ceramic cores, and surface strengthening mechanisms through glazing, work hardening and ion exchange. Purpose: The purpose of this study was to evaluate the effect of polish on flexural strength of feldspathic porcelain and to compare it with overglaze and autoglaze. Materials and Methods: In this experimental study, one brand of feldspathic porcelain (colorlogic, Ceramco was used and forty bars (25×6×3 mm were prepared according to ISO 6872 and ADA No. 69. The specimens were randomly divided into four groups: overglazed, auto glazed, fine polish and coarse polish (clinic polish. Flexural strength of each specimen was determined by three point bending test (Universal Testing Machine, Zwick 1494, Germany. Collected data was analyzed by ANOVA and post-hoc test with P<0.05 as the limit of significance. Results: A significant difference was observed among the studied groups (P<0.0001. According to post-hoc test, flexural strength in overglaze and fine polish group were significantly stronger than clinic polish and autoglaze group (P<0.001. Although the mean value for overglazed group was higher than fine polish group, this was not statistically significant (P=0.9. Also no statistical difference was seen between autoglazed and coarse polish group (P=0.2. Conclusion: Based on the findings of this study, flexural strength achieved by fine polish (used in this study can compete with overglazing the feldespathic porcelains. It also can be concluded that a final finishing procedure that involves fine polishing may be preferred to simple staining followed by self-glazing.

  16. Reclamation of niobium compounds from ionic liquid electrochemical polishing of superconducting radio frequency cavities

    Energy Technology Data Exchange (ETDEWEB)

    Wixtrom, Alex I. [Christopher Newport University, Newport News, VA (United States); Buhler, Jessica E. [Christopher Newport University, Newport News, VA (United States); Reece, Charles E. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Abdel-Fattah, Tarek M. [Christopher Newport University, Newport News, VA (United States)

    2013-06-01

    Recent research has shown that choline chloride (vitamin B4)-based solutions can be used as a greener alternative to acid-based electrochemical polishing solutions. This study demonstrated a successful method for electrochemical deposition of niobium compounds onto the surface of copper substrates using a novel choline chloride-based ionic liquid. Niobium ions present in the ionic liquid solution were dissolved into the solution prior to deposition via electrochemical polishing of solid niobium. A black coating was clearly visible on the surface of the Cu following deposition. This coating was analyzed using scanning electron microscopy (SEM), electron dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and X-ray fluorescence spectroscopy (XRF). This ionic liquid-based electrochemical deposition method effectively recycles previously dissolved niobium from electrochemical polishing of superconducting radio frequency (SRF) cavities.

  17. Evaluation of oxide-chemical mechanical polishing characteristics using ceria-mixed abrasive slurry

    Science.gov (United States)

    Lee, Youngkyun; Seo, Yong-Jin; Jeong, Haedo

    2012-10-01

    Chemical-mechanical polishing (CMP) characteristics of mixed abrasive slurry (MAS) were studied which was retreated by adding of Ceria (CeO2) abrasives within 1:10 diluted silica slurry (DSS). The slurry was designed for optimal performance which produces reasonable removal rate, acceptable polishing selectivity with respect to underlying layer, low surface defects after polishing, and good slurry stability. The modified abrasives in MAS are evaluated with respect to their particle size distribution, surface morphology, and CMP performances such as removal rate and non-uniformity. As an experimental result, we could obtain successful slurry characteristics compared with traditional silica slurry in the viewpoint of removal rate and non-uniformity.

  18. Smoking characteristics of Polish immigrants in Dublin.

    LENUS (Irish Health Repository)

    Kabir, Zubair

    2008-01-01

    BACKGROUND: This study examined two main hypotheses: a) Polish immigrants\\' smoking estimates are greater than their Irish counterparts (b) Polish immigrants purchasing cigarettes from Poland smoke "heavier" (>\\/= 20 cigarettes a day) when compared to those purchasing cigarettes from Ireland. The study also set out to identify significant predictors of \\'current\\' smoking (some days and everyday) among the Polish immigrants. METHODS: Dublin residents of Polish origin (n = 1,545) completed a previously validated Polish questionnaire in response to an advertisement in a local Polish lifestyle magazine over 5 weekends (July-August, 2007). The Office of Tobacco Control telephone-based monthly survey data were analyzed for the Irish population in Dublin for the same period (n = 484). RESULTS: Age-sex adjusted smoking estimates were: 47.6% (95% Confidence Interval [CI]: 47.3%; 48.0%) among the Poles and 27.8% (95% CI: 27.2%; 28.4%) among the general Irish population (p < 0.001). Of the 57% of smokers (n = 345\\/606) who purchased cigarettes solely from Poland and the 33% (n = 198\\/606) who purchased only from Ireland, 42.6% (n = 147\\/345) and 41.4% (n = 82\\/198) were "heavy" smokers, respectively (p = 0.79). Employment (Odds Ratio [OR]: 2.89; 95% CI: 1.25-6.69), lower education (OR: 3.76; 95%CI: 2.46-5.74), and a longer stay in Ireland (>24 months) were significant predictors of current smoking among the Poles. An objective validation of the self-reported smoking history of a randomly selected sub-sample immigrant group, using expired carbon monoxide (CO) measurements, showed a highly significant correlation coefficient (r = 0.64) of expired CO levels with the reported number of cigarettes consumed (p < 0.0001). CONCLUSION: Polish immigrants\\' smoking estimates are higher than their Irish counterparts, and particularly if employed, with only primary-level education, and are overseas >2 years.

  19. Behavior of molybdenum in mixed-oxide fuel

    International Nuclear Information System (INIS)

    Giacchetti, G.; Sari, C.

    1976-01-01

    Metallic molybdenum, Mo--Ru--Rh--Pd alloys, barium, zirconium, and tungsten were added to uranium and uranium--plutonium oxides by coprecipitation and mechanical mixture techniques. This material was treated in a thermal gradient similar to that existing in fuel during irradiation to study the behavior of molybdenum in an oxide matrix as a function of the O/(U + Pu) ratio and some added elements. Result of ceramographic and microprobe analysis shows that when the overall O/(U + Pu) ratio is less than 2, molybdenum and Mo--Ru--Rh--Pd alloy inclusions are present in the uranium--plutonium oxide matrix. If the O/(U + Pu) ratio is greater than 2, molybdenum oxidizes to MoO 2 , which is gaseous at a temperature approximately 1000 0 C. Molybdenum oxide vapor reacts with barium oxide and forms a compound that exists as a liquid phase in the columnar grain region. Molybdenum oxide also reacts with tungsten oxide (tungsten is often present as an impurity in the fuel) and forms a compound that contains approximately 40 wt percent of actinide metals. The apparent solubility of molybdenum in uranium and uranium--plutonium oxides, determined by electron microprobe, was found to be less than 250 ppM both for hypo- and hyperstoichiometric fuels

  20. Preparation of molybdenum oxide thin films by MOCVD

    Energy Technology Data Exchange (ETDEWEB)

    Guerrero, R. Martinez [Depto. de Ingenieria Metalurgica, ESIQIE-IPN, Mexico 07300, D.F. (Mexico); Garcia, J.R. Vargas [Depto. de Ingenieria Metalurgica, ESIQIE-IPN, Mexico 07300, D.F. (Mexico)]. E-mail: rvargasga@ipn.mx; Santes, V. [CIIEMAD-IPN, Miguel Othon de Mendizabal 485, Mexico 07700, D.F. (Mexico); Gomez, E. [Instituto de Quimica-UNAM, Circuito Exterior-Ciudad Universitaria, Mexico 04510, D.F. (Mexico)

    2007-05-31

    In this study, molybdenum oxide films were prepared in a horizontal hot-wall MOCVD apparatus using molybdenum dioxide acetylacetonate as precursor. The molybdenum precursor was synthesized from acetylacetone and molybdenum oxide powder. Thermal gravimetric (TG) and differential thermal analyses (DTA) of the precursor suggested the formation of molybdenum oxides around 430 {sup o}C (703 K). Thus, a range of deposition temperatures varying from 350 to 630 {sup o}C (623-903 K) was explored to investigate the effects on the nature of the molybdenum oxide films. X-ray diffraction (XRD) results showed that the films consisted of {alpha}-MoO{sub 3} phase at deposition temperatures ranging from 400 to 560 {sup o}C (673-833 K). Crystalline {alpha}-MoO{sub 3} films can be obtained from molybdenum dioxide acetylacetonate precursor, without need of a post-annealing treatment. The best crystalline quality was found in films having needle-like crystallites grown at deposition temperature of about 560 {sup o}C (833 K), which exhibit a strong (0 1 0) preferred orientation and a transparent visual appearance.

  1. Atomic layer deposition of molybdenum oxide using bis(tert-butylimido)bis(dimethylamido) molybdenum

    International Nuclear Information System (INIS)

    Bertuch, Adam; Sundaram, Ganesh; Saly, Mark; Moser, Daniel; Kanjolia, Ravi

    2014-01-01

    Molybdenum trioxide films have been deposited using thermal atomic layer deposition techniques with bis(tert-butylimido)bis(dimethylamido)molybdenum. Films were deposited at temperatures from 100 to 300 °C using ozone as the oxidant for the process. The Mo precursor was evaluated for thermal stability and volatility using thermogravimetric analysis and static vapor pressure measurements. Film properties were evaluated with ellipsometry, x-ray photoelectron spectroscopy, secondary ion mass spectroscopy, and secondary electron microscopy. The growth rate per cycle was determined to extend from 0.3 to 2.4 Å/cycle with <4% nonuniformity (1-sigma) with-in-wafer across a 150 mm wafer for the investigated temperature range

  2. Fabrication of micro-lenticular patterns using WEDM-grooving and electrolytic polishing

    Science.gov (United States)

    Park, Jong Wuk; Song, Ki Young; Chung, Do Kwan; Chu, Chong Nam

    2013-12-01

    Lenticular pattern panels have been used for displaying 3D effects and their precise fabrication methods have attracted great attention. In this study, we present a novel fabrication method for lenticular patterns on a stainless steel mold (AISI 304). The fabrication process was composed of two steps. First, the lenticular shape groove was machined by wire-electrical discharge machining (EDM) (WEDM-grooving). In this step, EDM was adopted because it is useful for machining hard-to-cut material such as WC-Co, stainless steel and titanium, and a newly developed wire grooving system ensures highly accurate machining. Second, electrolytic polishing was carried out afterward to improve the surface quality since the machined surface resulting from the WEDM-grooving was rough. The entire fabrication processes required a single machine and deionized water only; thus, the step change time was minimized and the method was eco-friendly. Parametric tests for the WEDM-grooving conditions as well as for the proper electrolytic polishing conditions (voltage, offset and feedrate) were executed to fabricate the grooves with fine surface. Excessive electrolytic polishing conditions caused pitting and damage from the additional sparks on the surface of the mold. On the other hand, inadequate machining conditions resulted in an incomplete electrolytic polishing process. Using this multi-step process, a lenticular pattern mold with high surface quality was machined. The lenticular pattern PDMS lens was successfully produced using the stainless steel mold.

  3. Amorphous molybdenum sulfides as hydrogen evolution catalysts.

    Science.gov (United States)

    Morales-Guio, Carlos G; Hu, Xile

    2014-08-19

    Providing energy for a population projected to reach 9 billion people within the middle of this century is one of the most pressing societal issues. Burning fossil fuels at a rate and scale that satisfy our near-term demand will irreversibly damage the living environment. Among the various sources of alternative and CO2-emission-free energies, the sun is the only source that is capable of providing enough energy for the whole world. Sunlight energy, however, is intermittent and requires an efficient storage mechanism. Sunlight-driven water splitting to make hydrogen is widely considered as one of the most attractive methods for solar energy storage. Water splitting needs a hydrogen evolution catalyst to accelerate the rate of hydrogen production and to lower the energy loss in this process. Precious metals such as Pt are superior catalysts, but they are too expensive and scarce for large-scale applications. In this Account, we summarize our recent research on the preparation, characterization, and application of amorphous molybdenum sulfide catalysts for the hydrogen evolution reaction. The catalysts can be synthesized by electrochemical deposition under ambient conditions from readily available and inexpensive precursors. The catalytic activity is among the highest for nonprecious catalysts. For example, at a loading of 0.2 mg/cm(2), the optimal catalyst delivers a current density of 10 mA/cm(2) at an overpotential of 160 mV. The growth mechanism of the electrochemically deposited film catalysts was revealed by an electrochemical quartz microcrystal balance study. While different electrochemical deposition methods produce films with different initial compositions, the active catalysts are the same and are identified as a "MoS(2+x)" species. The activity of the film catalysts can be further promoted by divalent Fe, Co, and Ni ions, and the origins of the promotional effects have been probed. Highly active amorphous molybdenum sulfide particles can also be prepared

  4. Evaluation of the COMSOL software electro-polishing of samples; Evaluation du logiciel COMSOL electropolissage d'echantillons

    Energy Technology Data Exchange (ETDEWEB)

    Bruchon, M

    2007-07-01

    The niobium electro-polishing is efficient if a viscous layer exists at the surface. In order to define parameters of samples electro-polishing, opened with difficulty to the experiments, the simulation is essential. This report presents works realized with the COMSOL software. The Nernst Planck equations have been associated to the Navier Stockes ones for an incompressible fluid. The study of the potential behaviour on the viscous layer and the mobility value have been detailed. (A.L.B.)

  5. Molybdenum plasma spray powder, process for producing said powder, and coating made therefrom

    International Nuclear Information System (INIS)

    Lafferty, W.D.; Cheney, R.F.; Pierce, R.H.

    1979-01-01

    Plasma spray powders of molybdenum particles containing 0.5 to 15 weight percent oxygen and obtained by reacting molybdenum particles with oxygen or oxides in a plasma, form plasma spray coatings exhibiting hardness comparable to flame sprayed coatings formed from molybdenum wire and plasma coatings of molybdenum powders. Such oxygen rich molybdenum powders may be used to form wear resistant coatings, such as for piston rings. (author)

  6. Structure and properties of iron alloys with vanadium and molybdenum

    International Nuclear Information System (INIS)

    Benrezhdal', A.; Tatarkina, A.L.; Loboda, T.P.; Raevskaya, M.V.; Sokolova, I.G.

    1984-01-01

    Investigation of the iron-vanadium-molybdenum system using the methods of microscopic, X-ray diffraction analyses as well as the method of hardness measurement has been undertaken. Isothermal cross section of the phase diagram at 1300 deg C is built. A considerable solubility of molybdenum and vanadium in iron is detected and in this connection corrosion behaviour of alloys in 10% sulfuric acid solution is studied. It is established that iron-3at.% vanadium-2at.% molybdenum alloy possesses the highest corrosion resistance

  7. Investigation of kinetics of molybdenum oxidation by the method of interference indication

    International Nuclear Information System (INIS)

    Zabrovskaya, V.F.; Vorontsov, E.S.; Korneeva, A.N.; Uglova, T.V.

    1976-01-01

    The peculiar kinetic characteristics of molybdenum oxidation with formation of interference-colored films on the surface were detected by the method of interference indication supplemented by electron diffraction. The interference-color spectrum was determined and the film structure and composition were elucidated. The activation energy of molybdenum oxidation increases with increase of film thickness and with decrease of temperature. This is explained in the light of the complex interaction between the processes of metal oxidation and oxide sublimation, and of the action of the electric field in the iridescence layers. The true value of the activation energy of molybdenum oxidation at 425-525 0 increases from 33 to 49 kcal/mole with increase of film thickness corresponding to a color change from light yellow to azure. The hypothesis of the apprecialbe influence of oxide sublimation on the apparent activation energy of metal oxidation with approach to a temperature of 525 0 was confirmed by the method of interference indication with direct measurement of the sublimation rate of the oxide in an argon atmosphere

  8. COMBINED RETENTION OF MOLYBDENUM AND SULFUR IN SIMULATED HIGH LEVEL WASTE GLASS

    Energy Technology Data Exchange (ETDEWEB)

    Fox, K.

    2009-10-16

    This study was undertaken to investigate the effect of elevated sulfate and molybdenum concentrations in nuclear waste glasses. A matrix of 24 glasses was developed and the glasses were tested for acceptability based on visual observations, canister centerline-cooled heat treatments, and chemical composition analysis. Results from the chemical analysis of the rinse water from each sample were used to confirm the presence of SO{sup 2-}{sub 4} and MoO{sub 3} on the surface of glasses as well as other components which might form water soluble compounds with the excess sulfur and molybdenum. A simple, linear model was developed to show acceptable concentrations of SO{sub 4}{sup 2-} and MoO{sub 3} in an example waste glass composition. This model was constructed for scoping studies only and is not ready for implementation in support of actual waste vitrification. Several other factors must be considered in determining the limits of sulfate and molybdenum concentrations in the waste vitrification process, including but not limited to, impacts on refractory and melter component corrosion, effects on the melter off-gas system, and impacts on the chemical durability and crystallization of the glass product.

  9. Production of molybdenum-99 for medical use

    International Nuclear Information System (INIS)

    Pervez, S.; Khan, Q.; Mirza, J.A.; Hussain, S.; Asif, M.; Khan, M.M.; Khalidand, U.; Siddique, M.U.

    2012-01-01

    Production of Molybdenum-99 (/sup 99/Mo) was carried out by irradiating 3 HEU targets in the core of Pakistan Research Reactor-1 (PARR-1) for 12 hours. The average radiochemical separation yield from various batches was 60-70%. Radionuclidic purity of final product was determined by gamma, alpha and beta spectrometry, while radiochemical purity was determined by paper chromatography. The produced /sup 99/Mo met all the criteria fixed in various pharmacopoeias. Pakgen /sup 99m/Tc generators were manufactured by indigenous /sup 99/Mo and sent to various medical centers for clinical trials. All the users were quite satisfied with the performance of Pakgen /sup 99m/Tc generators. (orig./A.B.)

  10. Molybdenum-base cermet fuel development

    International Nuclear Information System (INIS)

    Gurwell, W.E.; Moss, R.W.; Pilger, J.P.; White, G.D.

    1987-07-01

    Development of a multimegawatt (MMW) space nuclear power system requires identification and resolution of several technical feasibility issues before selecting one or more promising system concepts. Demonstration of reactor fuel fabrication technology is required for cermet-fueled reactor concepts. MMW reactor fuel development activity at Pacific Northwest Laboratory (PNL) is focused on producing a molybdenum-matrix uranium-nitride (UN) fueled cermet. This cermet is to have a high matrix density (≥95%) for high strength and high thermal conductance coupled with a high particle (UN) porosity (∼25%) for retention of released fission gas at high burnup. Fabrication process development involves the use of porous TiN microspheres as surrogate fuel material until porous UN microspheres become available. Process development has been conducted in the areas of microsphere synthesis, particle sealing/coating, and high-energy-rate forming (HERF) and vacuum hot press consolidation techniques. This paper summarizes the status of these activities

  11. Microplastic relaxations of single and polycrystalline molybdenum

    Energy Technology Data Exchange (ETDEWEB)

    Pichl, W.; Weiss, B. [Wien Univ. (Austria). Inst. fuer Materialphysik; Chen, D.L.

    1998-05-01

    The microplasticity of high-purity molybdenum single crystals and of Mo polycrystals of technical purity has been investigated by relaxation step tests in uniaxial compression. A new model for the evaluation of relaxation tests in the microplastic range of b.c.c metals is presented which takes into account the decrease of the mobile dislocation density due to exhaustion of non-screw dislocations. The model allows an independent determination of the activation volume and of the microstructure parameters controlling dislocation exhaustion. The results indicate that in the high-purity single crystals the deformation rate is controlled by interactions of non-screw dislocations with the grown-in network. In the polycrystals additional interactions with impurity atoms seem to occur. In the single crystals the activity and subsequent exhaustion of two different glide systems was observed, followed by a gradual onset of screw dislocation motion. (orig.) 26 refs.

  12. Scattering of fast neutrons from elemental molybdenum

    International Nuclear Information System (INIS)

    Smith, A.B.; Guenther, P.T.

    1982-11-01

    Differential broad-resolution neutron-scattering cross sections of elemental molybdenum were measured at 10 to 20 scattering angles distributed between 20 and 160 degrees and at incident-neutron energy intervals of approx. = 50 to 200 keV from 1.5 to 4.0 MeV. Elastically-scattered neutrons were fully resolved from inelastic events. Lumped-level inelastic-neutron-scattering cross sections were determined corresponding to observed excitation energies of; 789 +- 23, 195 +- 23, 1500 +- 34, 1617 +- 12, 1787, 1874, 1991, 2063 +- 24, 2296, 2569 and 2802 keV. An optical-statistical model was deduced from the measured elastic-scattering results. The experimental values were compared with the respective quantities given in ENDF/B-V

  13. Polish Academy of Sciences Great Dictionary of Polish [Wielki słownik języka polskiego PAN

    Directory of Open Access Journals (Sweden)

    Piotr Žmigrodzki

    2014-12-01

    Full Text Available The paper describes a lexicographical project involving the development of the newest general dictionary of the Polish language: the Polish Academy of Sciences Great Dictionary of Polish [Wielki słownik języka polskiego PAN]. The project is coordinated by the Institute of Polish Language at the Polish Academy of Sciences and carried out in collaboration with linguists and lexicographers from several other Polish academic centres. The paper offers a brief description of the genesis of the project and the scope of information included in the dictionary, the organisation of work, the life of the dictionary on the Web as well as the plans for the future.

  14. Friction Properties of Polished Cvd Diamond Films Sliding against Different Metals

    Science.gov (United States)

    Lin, Zichao; Sun, Fanghong; Shen, Bin

    2016-11-01

    Owing to their excellent mechanical and tribological properties, like the well-known extreme hardness, low coefficient of friction and high chemical inertness, chemical vapor deposition (CVD) diamond films have found applications as a hard coating for drawing dies. The surface roughness of the diamond films is one of the most important attributes to the drawing dies. In this paper, the effects of different surface roughnesses on the friction properties of diamond films have been experimentally studied. Diamond films were fabricated using hot filament CVD. The WC-Co (Co 6wt.%) drawing dies were used as substrates. A gas mixture of acetone and hydrogen gas was used as the feedstock gas. The CVD diamond films were polished using mechanical polishing. Polished diamond films with three different surface roughnesses, as well as the unpolished diamond film, were fabricated in order to study the tribological performance between the CVD diamond films and different metals with oil lubrication. The unpolished and polished CVD diamond films are characterized with scanning electron microscope (SEM), atomic force microscope (AFM), surface profilometer, Raman spectrum and X-ray diffraction (XRD). The friction examinations were carried out by using a ball-on-plate type reciprocating friction tester. Low carbide steel, stainless steel, copper and aluminum materials were used as counterpart balls. Based on this study, the results presented the friction coefficients between the polished CVD films and different metals. The friction tests demonstrate that the smooth surface finish of CVD diamond films is beneficial for reducing their friction coefficients. The diamond films exhibit low friction coefficients when slid against the stainless steel balls and low carbide steel ball, lower than that slid against copper ball and aluminum ball, attributed to the higher ductility of copper and aluminum causing larger amount of wear debris adhering to the sliding interface and higher adhesive

  15. The Effect of Grinding and Polishing Procedure of Tool Steels in Sheet Metal Forming

    DEFF Research Database (Denmark)

    Lindvall, F.; Bergström, J.; Krakhmalev, P.

    2010-01-01

    The surface finish of tools in sheet metal forming has a large influence on the performance of the forming tool. Galling, concern of wear in sheet metal forming, is a severe form of adhesive wear where sheet material is transferred on to the tool surface. By polishing the tools to a fine surface ...... 40 and Vanadis 6 and up to ten different grinding and polishing treatments were tested against AISI 316 stainless steel. The tests showed that an optimum surface preparation might be found at the transition between abrasive and adhesive wear.......The surface finish of tools in sheet metal forming has a large influence on the performance of the forming tool. Galling, concern of wear in sheet metal forming, is a severe form of adhesive wear where sheet material is transferred on to the tool surface. By polishing the tools to a fine surface...... finish, material pick-up has traditionally been reduced, but some surface preparations withstand adhesive wear better. To investigate the effect on galling performance of different surface preparations lubricated tests have been performed using a strip reduction rig. Two different tool materials, Vancron...

  16. Innovative Molybdenum Alloy for Extreme Operating Conditions Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Molybdenum has been identified as a promising material for many high temperature NASA applications due to its high melting temperature, resistance to liquid metals,...

  17. GEMAS: Molybdenum Spatial Distribution Patterns in European Soil

    Science.gov (United States)

    Cicchella, Domenico; Zuzolo, Daniela; Demetriades, Alecos; De Vivo, Benedetto; Eklund, Mikael; Ladenberger, Anna; Negrel, Philippe; O'Connor, Patrick

    2017-04-01

    Molybdenum is an essential trace element for both plants and animals as well as for human being. It is one such trace element for which potential health concerns have been raised but for which few data exist and little investigation or interpretation of distributions in soils has been made. The main goal of this study was to fill this gap. Molybdenum (Mo) concentrations are reported for the Greece associated with sulfides mineralizations and in Slovenia and Croatia where are probably related to the long weathering history of karstic residual soils. Anomalous concentrations in some areas of Ireland represent a clear example of how an excess of molybdenum has produced potentially toxic pastures. In fact, these give rise to problems particularly in young cattle when excess molybdenum in the herbage acts as an antagonist, which militates against efficient copper absorption by the animal.

  18. Recovering and recycling uranium used for production of molybdenum-99

    Science.gov (United States)

    Reilly, Sean Douglas; May, Iain; Copping, Roy; Dale, Gregory Edward

    2017-12-12

    A processes for recycling uranium that has been used for the production of molybdenum-99 involves irradiating a solution of uranium suitable for forming fission products including molybdenum-99, conditioning the irradiated solution to one suitable for inducing the formation of crystals of uranyl nitrate hydrates, then forming the crystals and a supernatant and then separating the crystals from the supernatant, thus using the crystals as a source of uranium for recycle. Molybdenum-99 is recovered from the supernatant using an adsorbent such as alumina. Another process involves irradiation of a solid target comprising uranium, forming an acidic solution from the irradiated target suitable for inducing the formation of crystals of uranyl nitrate hydrates, then forming the crystals and a supernatant and then separating the crystals from the supernatant, thus using the crystals as a source of uranium for recycle. Molybdenum-99 is recovered from the supernatant using an adsorbent such as alumina.

  19. Alkaline elution of uranium and molybdenum and their recovery

    International Nuclear Information System (INIS)

    Song Wenlan; Wu Peisheng; Zhao Pinzhi; Tao Dening; Xie Chaoyan

    1987-01-01

    The uranium and molybdenum can be simultaneously eluted by using eluant (NH 4 ) 2 CO 3 + (NH 4 ) 2 SO 4 from resin loaded uranium and molybdenum. The ADU is precipitated from eluant by volatilization of ammonia. The molybdenum is extracted by TFA-TBP-kerosene from the filtrate at pH 3.0-3.2 with molybdenum extraction > 98%. Uranium is nearly not extracted. The precipitation of Mo is reached by sulphuric acid after stripping and the ammonium multimolybdate is obtained. This process can give the total recovery more than 99% for U and 90% for Mo. Because of the use of sulphate salt system, the hazard of NO 3 - can be avoided

  20. Molybdenum-A Key Component of Metal Alloys

    Science.gov (United States)

    Kropschot, S.J.

    2010-01-01

    Molybdenum, whose chemical symbol is Mo, was first recognized as an element in 1778. Until that time, the mineral molybdenite-the most important source of molybdenum-was believed to be a lead mineral because of its metallic gray color, greasy feel, and softness. In the late 19th century, French metallurgists discovered that molybdenum, when alloyed (mixed) with steel in small quantities, creates a substance that is remarkably tougher than steel alone and is highly resistant to heat. The alloy was found to be ideal for making tools and armor plate. Today, the most common use of molybdenum is as an alloying agent in stainless steel, alloy steels, and superalloys to enhance hardness, strength, and resistance to corrosion.

  1. Air-powder polishing on self-ligating brackets after clinical use: effects on debris levels

    Directory of Open Access Journals (Sweden)

    Mônica L. S. Castro Aragón

    Full Text Available ABSTRACT Introduction: Debris buildup on brackets and arch surfaces is one of the main factors that can influence the intensity of friction between bracket and orthodontic wire. Objective: This study sought to evaluate the effect of air-powder polishing cleaning on debris levels of self-ligating ceramic brackets at the end of orthodontic treatment, compared to the behavior of conventional brackets. Methods: Debris levels were evaluated in metal conventional orthodontic brackets (n = 42 and ceramic self-ligating brackets (n = 42 on canines and premolars, arranged in pairs. There were brackets with and without air-powder polishing. At the end of orthodontic treatment, a hemiarch served as control and the contralateral hemiarch underwent prophylaxis with air-powder polishing. Debris buildup in bracket slots was assessed through images, and Wilcoxon test was used to analyze the results. Results: The median debris levels were statistically lower in the conventional metal brackets compared to self-ligating ones (p = 0.02, regarding brackets not submitted to air-powder polishing. Polishing significantly reduced debris buildup to zero in both systems, without differences between groups. Conclusions: Ceramic self-ligating brackets have a higher debris buildup in comparison to conventional metal brackets in vivo, but prophylaxis with sodium bicarbonate jet was effective in reducing debris levels in self-ligating and also in conventional brackets.

  2. Effect of acetic acid on wet patterning of copper/molybdenum thin films in phosphoric acid solution

    Energy Technology Data Exchange (ETDEWEB)

    Seo, Bo.-Hyun; Lee, Sang-Hyuk; Park, In-Sun [Department of Materials Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Seo, Jong Hyun, E-mail: jhseo@kau.ac.kr [Department of Materials Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Choe, HeeHwan; Jeon, Jae-Hong [School of Electronics, Telecommunications and Computer Engineering, Korea Aerospace University, Hwajeon, Goyang, Gyonggi-do 412-791 (Korea, Republic of); Hong, Munpyo [Display and Semiconductor Physics, Korea University (Korea, Republic of); Lee, Yong Uk [PETEC (The Printable Electronics Technology Centre) (United Kingdom); Winkler, Joerg [PLANSEE Metal GmbH, Metallwerk-Plansee-Str. 71A-6600, Reutte (Austria)

    2011-08-01

    Copper metallization is a key issue for high performance thin film transistor (TFT) technology. A phosphoric acid based copper etchant is a potentially attractive alternative to the conventional hydrogen peroxide based etchant due to its longer-life expectancy time and higher stability in use. In this paper, it is shown that amount of the acetic acid in the phosphoric based copper etchant plays an important role in controlling the galvanic reaction between the copper and the molybdenum. As the concentration of acetic acid in the phosphoric mixture solution increased from 0 M to 0.4 M, the measured galvanic current density dropped from 32 mA/cm{sup 2} to 26 mA/cm{sup 2}, indicating that the acetic acid induces the lower galvanic reaction between the copper and the molybdenum in the solution. From the XPS analysis, with the addition of the acetic acid, the thickness of the protective MoO{sub 2} passive film covering the molybdenum surface grew and the dissolution rate of the molybdenum thin film decreased. However, the dissolution rate of the copper thin film increased as the concentration of acetic acid in the mixture solution increased.

  3. Effect of acetic acid on wet patterning of copper/molybdenum thin films in phosphoric acid solution

    International Nuclear Information System (INIS)

    Seo, Bo.-Hyun; Lee, Sang-Hyuk; Park, In-Sun; Seo, Jong Hyun; Choe, HeeHwan; Jeon, Jae-Hong; Hong, Munpyo; Lee, Yong Uk; Winkler, Joerg

    2011-01-01

    Copper metallization is a key issue for high performance thin film transistor (TFT) technology. A phosphoric acid based copper etchant is a potentially attractive alternative to the conventional hydrogen peroxide based etchant due to its longer-life expectancy time and higher stability in use. In this paper, it is shown that amount of the acetic acid in the phosphoric based copper etchant plays an important role in controlling the galvanic reaction between the copper and the molybdenum. As the concentration of acetic acid in the phosphoric mixture solution increased from 0 M to 0.4 M, the measured galvanic current density dropped from 32 mA/cm 2 to 26 mA/cm 2 , indicating that the acetic acid induces the lower galvanic reaction between the copper and the molybdenum in the solution. From the XPS analysis, with the addition of the acetic acid, the thickness of the protective MoO 2 passive film covering the molybdenum surface grew and the dissolution rate of the molybdenum thin film decreased. However, the dissolution rate of the copper thin film increased as the concentration of acetic acid in the mixture solution increased.

  4. Effect of liquid-polish coating on in vitro biofilm accumulation on provisional restorations: Part 2.

    Science.gov (United States)

    Davidi, Michael Perez; Beyth, Nurit; Weiss, Ervin I; Weiss, Ervin I; Eilat, Yuval; Feuerstein, Osnat; Sterer, Nir

    2008-01-01

    In part 1 of this study, the authors showed that coating polymethyl methacrylate (PMMA) provisional restorations with bonding resin (BR) or liquid polish (LP) significantly reduced early in vivo biofilm formation on these restorations. The aim of the present study was to determine the mechanism through which these materials inhibit biofilm formation. The antimicrobial properties of the tested materials were examined using the agar diffusion test (ADT) and the direct contact test (DCT). Surface energy was determined using contact angle measurements; salivary protein adsorption was analyzed by polyacrylamide gel electrophoresis (SDS-PAGE). ADT and DCT showed that the tested materials had no antimicrobial properties. Contact angle measurements revealed that liquid polish and PMMA have a similar contact angle, tending toward the hydrophobic region, and that bonding resin was more hydrophilic. SDS-PAGE analysis showed a significant reduction in salivary protein adsorption to the tested materials compared with that to the PMMA control. Liquid polish prevents biofilm formation by preventing protein adsorption.

  5. Hard and soft x-ray study of the correlation between substrate quality and multilayer performance for Co/C coating produced by electron beam evaporation using ion polishing

    DEFF Research Database (Denmark)

    Abdali, S.; Christensen, Finn Erland; Spiller, E.

    1995-01-01

    Polished silicon crystals, lacquered aluminum foil, and float glass substrates with respect to surface roughness. Co/C multilayers were then deposited by electron-beam evaporation with in situ monitoring x-ray signal and ion polishing (Kr+) for the metal layer. The specular as well as the transve......Polished silicon crystals, lacquered aluminum foil, and float glass substrates with respect to surface roughness. Co/C multilayers were then deposited by electron-beam evaporation with in situ monitoring x-ray signal and ion polishing (Kr+) for the metal layer. The specular as well...... of these investigations and a comparison between the coating performances are discussed....

  6. Magnetron Sputtered Molybdenum Oxide for Application in Polymers Solar Cells

    Science.gov (United States)

    Sendova-Vassileva, M.; Dikov, Hr; Vitanov, P.; Popkirov, G.; Gergova, R.; Grancharov, G.; Gancheva, V.

    2016-10-01

    Thin films of molybdenum oxide were deposited by radio frequency (RF) magnetron sputtering in Ar from a MoO3 target at different deposition power on glass and silicon substrates. The thickness of the films was determined by profilometer measurements and by ellipsometry. The films were annealed in air at temperatures between 200 and 400°C in air. The optical transmission and reflection spectra were measured. The conductivity of the as deposited and annealed films was determined. The crystal structure was probed by Raman spectroscopy. The oxidation state of the surface was studied by X-ray photoelectron spectroscopy (XPS) spectroscopy. The deposition technique described above was used to experiment with MoOx as a hole transport layer (HTL) in polymer solar cells with bulk hetrojunction active layer, deposited by spin coating. The performance of these layers was compared with poly(3,4-ethylenedioxythiophene):polystyrene sulfonate (PEDOT:PSS), which is the standard material used in this role. The measured current-voltage characteristics of solar cells with the structure glass/ITO/HTL/Poly(3-hexyl)thiophene (P3HT):[6,6]-phenyl-C61- butyric acid methyl ester (PCBM)/Al demonstrate that the studied MoOx layer is a good HTL and leads to comparable characteristics to those with PEDOT:PSS. On the other hand the deposition by magnetron sputtering guarantees reliable and repeatable HTLs.

  7. Synthesis of low oxygen concentration molybdenum nitride films

    International Nuclear Information System (INIS)

    Roberson, S.L.; Davis, R.F.; Finello, D.

    1998-01-01

    Polycrystalline, small grain size, 15 μm thick Mo x N (x = 1 and 2) films containing ∼60 at.% γ-Mo 2 N and ∼40 at.% δ-MoN and void of Auger detectable concentrations of molybdenum oxides, have been prepared on 50-μm thick nitrided Ti substrates via programmed reaction and subsequent anneal at 750 C for 2 h of the precursor MoO 3 films with NH 3 . The latter films were prepared via liquid spray pyrolysis of an MoCl 5 /methanol mixture in air at 500 C. By contrast, residual MoO 2 occurred near the film-substrate interface in Mo x N films produced using the same programmed reaction but where MoO 3 had been deposited on bare Ti substrates. The change in density of MoO 3 (ρ = 4.69 gcm -3 ) to γ-Mo 2 N (ρ = 9.50 gcm -3 ) and δ-MoN (ρ = 9.05 gcm -3 ), as well as the nature of the topotactic conversion, produced grains which had a calculated average size of 10 nm and which exhibited good adhesion to the substrate. Variations in the conversion heating rates and the NH 3 flow rates also affected both the phase composition and the average grain size of the intermediate and the final reaction products. Scanning electron microscopy (SEM) of the Mo x N films revealed a highly porous surface morphology. (orig.)

  8. Hydrogen reduction of molybdenum oxide at room temperature

    Science.gov (United States)

    Borgschulte, Andreas; Sambalova, Olga; Delmelle, Renaud; Jenatsch, Sandra; Hany, Roland; Nüesch, Frank

    2017-01-01

    The color changes in chemo- and photochromic MoO3 used in sensors and in organic photovoltaic (OPV) cells can be traced back to intercalated hydrogen atoms stemming either from gaseous hydrogen dissociated at catalytic surfaces or from photocatalytically split water. In applications, the reversibility of the process is of utmost importance, and deterioration of the layer functionality due to side reactions is a critical challenge. Using the membrane approach for high-pressure XPS, we are able to follow the hydrogen reduction of MoO3 thin films using atomic hydrogen in a water free environment. Hydrogen intercalates into MoO3 forming HxMoO3, which slowly decomposes into MoO2 +1/2 H2O as evidenced by the fast reduction of Mo6+ into Mo5+ states and slow but simultaneous formation of Mo4+ states. We measure the decrease in oxygen/metal ratio in the thin film explaining the limited reversibility of hydrogen sensors based on transition metal oxides. The results also enlighten the recent debate on the mechanism of the high temperature hydrogen reduction of bulk molybdenum oxide. The specific mechanism is a result of the balance between the reduction by hydrogen and water formation, desorption of water as well as nucleation and growth of new phases.

  9. Influence of molybdenum on thermal properties of CMCs

    International Nuclear Information System (INIS)

    Khan, A.A.; Labbe, J.C.

    1996-01-01

    Aluminum nitride (AlN) has received considerable attention in recent years because of its high thermal conductivity. AlN is currently used in thermal management applications. AlN single crystals have a thermal conductivity as high as 320 W·m -1 ·K -1 , whereas the thermal conductivity of polycrystalline AlN varies from 80 to 200 W· -1 ·K -1 , depending on the microstructure and composition of the sintered ceramic. Conventional AlN ceramics, however, do not exhibit thermal conductivity as high as expected because of their relatively low purity and sinterability. Purity, particle-size distribution, oxygen content and specific surface area affect sinterability and thermal properties of AlN. It is difficult to produce pure AlN powder and dense, sintered AlN materials that are free from oxygen impurities. The effect of adding a ductile metallic phase (aluminum) to improve the mechanical behavior of AlN is therefore studied. Aluminum, because of its low melting point, degrades the mechanical properties of AlN at high temperatures. A refractory metal with high thermal conductivity is the best choice as a second phase additive. The influence of molybdenum addition on the thermal properties of AlN has been studied

  10. Grinding and polishing of conformal windows and domes

    Science.gov (United States)

    Fess, Edward; Ross, James; Matthews, Greg

    2017-05-01

    Conformal optics require special manufacturing techniques to produce them to optical tolerances. In many cases the materials used are very hard optical ceramics that present additional manufacturing challenges due to their hardness and grain structure. OptiPro has developed grinding technologies such as OptiSonic grinding, as well as sub-aperture polishing technologies like UltraForm Finishing (UFF) to manufacture these challenging components. We have also developed a custom computer aided manufacturing (CAM) software package, ProSurf, to generate the complex tool paths for both grinding and polishing processes. One of the main advantages of ProSurf over traditional CAM software packages is that it uses metrology feedback for deterministic corrections. The metrology input can be obtained from OptiPro's 5-axis UltraSurf metrology system, which is capable of measuring these complex shapes to sub-micron accuracies. Through the development of these technologies much work has been performed in creating, measuring and analyzing the alignment fiducials or datum's used to qualify the location of the optical surfaces. Understanding the sensitivity of the optical surface to any datum misalignment is critical to knowing not only where the part is in space, but how good the optical surfaces are to each other. Working with the optical designer to properly tolerance surfaces to these datums is crucial. This paper will present the technologies developed by OptiPro to manufacture conformal windows as well as information related to the optical surfaces sensitivity to datums and how accurately those datums can be measured.

  11. Influence of Finishing and Polishing Techniques and Abrasion on Transmittance and Roughness of Composite Resins.

    Science.gov (United States)

    Carneiro, Pma; Ramos, T M; de Azevedo, C S; de Lima, E; de Souza, Shj; Turbino, M L; Cesar, P F; Matos, A B

    The aim of this study was to evaluate the influence of finishing and polishing systems and toothbrush abrasion on transmittance (T) and surface roughness (Ra) of three composite resins (Filtek Z350 XT, Tetric N-Ceram, and IPS Empress Direct). Eighteen resin disks (10 mm diameter × 2 mm thick) finished by polyester strips had initial surface smoothness recorded, representing phase 1 (P1). Specimens were divided into three groups (n=6) according to the finishing/polishing instrument used (OneGloss, TopGloss, and Sof-Lex) to compose phase 2 samples (P2). Then specimens were subjected to 514 cycles of toothbrush simulation using a toothpaste slurry, with a constant load applied to soft bristles, and were then washed (phase 3=P3). After each phase, the specimens were examined by an optical profiler and spectrophotometer to measure Ra and T. Data were analyzed by analysis of variance, Tukey and Pearson tests. T values were statistically influenced by composite resin ( p=0.000) and phase of measurement ( p=0.000) factors, while the finishing/polishing system used ( p=0.741) did not affect T. On the other hand, Ra values were statistically affected by the factor finishing/polishing system ( p=0.000), but not by composite resin ( p=0.100) and phase of measurement ( p=0.451). Tetric N-Ceram and Empress Direct presented higher values of roughness when polished by OneGloss, while TopGloss and Sof-Lex showed a lower roughness. It can be concluded that composite resins transmitted more light after dental abrasion. Transmittance of composite resins was not modified by the distinct roughness created by finishing/polishing instruments.

  12. Experimental study on polishing performance of CeO2 and nano-SiO2 mixed abrasive

    Science.gov (United States)

    He, Qiang

    2018-02-01

    In this paper, superfine SiO2 nanoparticles are utilized as composite abrasive additive to improve the polishing property of CeO2, which is prepared through chemical precipitation method by rare-earth chloride as raw materials, silicofluoric acid as fluoride, Na2CO3 as modifier, and NH4HCO3 as precipitator. XRD, SEM, particle size analyzer, and atomic force microscopy are applied to characterize the physical structure, morphology, and size distribution. Furthermore, the as-prepared composite abrasive is used to perform chemical mechanical polishing (CMP) experiment on K9 glass to identify the impact of different mass fraction of SiO2 on the CMP property of work materials. The results show that the composite abrasive contained 0.5% SiO2 has the best polishing property, the surface roughness, and material removal rate of glass after polishing can reach at 1.3157 nm and 22.6 nm/min, respectively.

  13. Femtosecond laser surface structuring of molybdenum thin films

    CSIR Research Space (South Africa)

    Kotsedi, L

    2015-10-01

    Full Text Available , 20133 Milano, Italy e Center for Nano Science and Technology, Istituto Italiano di Tecnologia, Via Pascoli 70/3, 20133 Milano, Italy f Institute for Photonics and Nanotechnologies (IFN)–CNR, Piazza Leanardo Da Vinci, 32, 20133 Milano, Italy...

  14. Microbiological flora and nail polish: a brief report.

    Science.gov (United States)

    Rayan, G M; Flournoy, D J; Schlageter, P

    1994-11-01

    Removing nail polish and prosthetic nails from operating room (OR) personnel prior to scrubbing and from patients prior to hand surgery is recommended but not practiced in many hospitals. There is concern that nail polish can act as a vehicle for the transfer of infectious agents. This study was designed to determine the incidence of microbiological flora of nail polish in a clinical setting.

  15. 21 CFR 872.6030 - Oral cavity abrasive polishing agent.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Oral cavity abrasive polishing agent. 872.6030... (CONTINUED) MEDICAL DEVICES DENTAL DEVICES Miscellaneous Devices § 872.6030 Oral cavity abrasive polishing agent. (a) Identification. An oral cavity abrasive polishing agent is a device in paste or powder form...

  16. Combined Ultrasonic Elliptical Vibration and Chemical Mechanical Polishing of Monocrystalline Silicon

    Directory of Open Access Journals (Sweden)

    Liu Defu

    2016-01-01

    Full Text Available An ultrasonic elliptical vibration assisted chemical mechanical polishing(UEV-CMP is employed to achieve high material removal rate and high surface quality in the finishing of hard and brittle materials such as monocrystalline silicon, which combines the functions of conventional CMP and ultrasonic machining. In theultrasonic elliptical vibration aided chemical mechanical polishingexperimental setup developed by ourselves, the workpiece attached at the end of horn can vibrate simultaneously in both horizontal and vertical directions. Polishing experiments are carried out involving monocrystalline silicon to confirm the performance of the proposed UEV-CMP. The experimental results reveal that the ultrasonic elliptical vibration can increase significantly the material removal rate and reduce dramatically the surface roughness of monocrystalline silicon. It is found that the removal rate of monocrystalline silicon polished by UEV-CMP is increased by approximately 110% relative to that of conventional CMP because a passive layer on the monocrystalline silicon surface, formed by the chemical action of the polishing slurry, will be removed not only by the mechanical action of CMP but also by ultrasonic vibration action. It indicates that the high efficiency and high quality CMP of monocrystalline silicon can be performed with the proposed UEV-CMP technique.

  17. Professional Training of Economists at Polish Universities

    Science.gov (United States)

    Ogienko, Olena

    2016-01-01

    Polish experience in professional training of economists at university has been generalized. Structural, content and procedural peculiarities of the training have been defined. It has been proved that key factors for reforming economic education in Poland are globalization, internationalization, integration, technologization and informatization.…

  18. Knowledge Mobilisation in the Polish Education System

    Science.gov (United States)

    Fazlagic, Jan; Erkol, Arif

    2015-01-01

    Poland has made substantial progress in improving the quality of its education system in recent years. This paper aims to describe the situation of the Polish education system from a knowledge management perspective and, to some extent, through innovation policies in education. The many challenges, this paper argues, can be tackled only through…

  19. Sexual Health of Polish Athletes with Disabilities

    Directory of Open Access Journals (Sweden)

    Ryszard Plinta

    2015-06-01

    Full Text Available The purpose of this study was to determine sexual functioning of Polish athletes with disabilities (including paralympians. The study encompassed 218 people with physical disabilities, aged between 18 and 45 (149 men and 69 women. The entire research population was divided into three groups: Polish paralympians (n = 45, athletes with disabilities (n = 126 and non-athletes with disabilities (n = 47. The quality of sexual life of Polish paralympians was measured by using the Polish version of Female Sexual Function Index and International Index of Erectile Function. Clinically significant erectile dysfunctions were most often diagnosed in non-athletes (83.33% with 50% result of severe erectile dysfunctions, followed by athletes and paralympians with comparable results of 56.98% and 54.17% respectively (p = 0.00388. Statistically significant clinical sexual dysfunctions concerned lubrication, orgasm as well as pain domains, and prevailed among female non-athletes (68.42%, 68.42% and 57.89%. Practising sports at the highest level has a favourable effect on the sexuality of men and women with physical disabilities. Men with physical disabilities manifest more sexual disorders than women, an aspect which should be considered by health-care professionals working with people with disabilities.

  20. Polish Complementary Schools in Iceland and England

    Science.gov (United States)

    Zielinska, Malgorzata; Kowzan, Piotr; Ragnarsdóttir, Hanna

    2014-01-01

    Since 2004, the opening of labour markets has spurred a considerable number of Poles to emigrate e.g. to Iceland and England. Families with school age children have had the challenge of adapting to foreign environments and school systems. Polish complementary schools have played an important, albeit ambivalent, role in this process. Through focus…

  1. Influence of sulphur and molybdenum on pitting corrosion of stainless steel in chloride solutions

    International Nuclear Information System (INIS)

    Brennert, S.

    1979-01-01

    When a stainless steel corrodes in a neutral chloride solution with the formation of pits, the anode solution in the pits has a low pH value, is rich in chlorides and contains some H 2 S, formed when the sulphide inclusions dissolve in the acid anode solution. The aim of the research work has been to study how the anode reaction is influenced firstly by the H 2 S content of the anode solution and secondly by the S content and the Mo content of the steel. In the first part of the investigation an active surface of a stainless steel type 18-8 was polarized in acid chloride solutions with different pH values and different H 2 S contents up to 100 ppm at increasing potentials. The result was that hydrogen ions and H 2 S widened the active region in the polarization curve in all directions. In the second part of the investigation active surfaces of austenitic steels with different S and Mo contents were polarized in an acid chloride solution at increasing potentials. The result was that S in the steel widened and Mo contracted the active region in the polarization curve in all directions. Applied to pits, developing under conditions in practice, the results indicate that sulphur increases and molybdenum reduces the potential difference in the corrosion cell but the effect is not very great and the corrosion rate is changed only moderately. The essential influence of the two components is supposed to be that sulphur will counteract and molybdenum will facilitate the passivation of the active surface in a pit. This will influence both the moment when a pit will start to grow and the moment when it will stop. Thus on average the life of a pit in a steel will be extended with increasing sulphur content and shortened with increasing molybdenum content. (author)

  2. Transformation of the Polish Banking Sector

    Directory of Open Access Journals (Sweden)

    Marek Stefański

    2009-07-01

    Full Text Available In the post-war period the banking system in Poland underwent two important system transitions: after 1946 and after 1989. The third transformation began after May 1, 2004, but it did not have a systemic character. The Polish banking sector started to operate on the Single European Market. The first part of the paper is devoted to the problems of the banks transformations after 1989 with a special focus on the quantitative development of banks in 19892008, and on subsequent privatisation and consolidation processes. The former intensified in 19891999, and the latter in 19992002. The consolidation process was very noticeable in the sector of cooperative banks after 1994. The second part of the paper includes an economic and financial analysis of the banks. A lot of attention was paid to the liquidity of the banking sector. It was assessed as good, which was confirmed by a short-term rating of Moodys and by the Financial Stability Report 2009, published by the National Bank of Poland in June 2009. The comparison of the net profit of the banking sector in 19972008 shows its dependence on the economic situation and policy. The number of banks with capital adequacy ratio well above the minimum required by the banking supervision is rising. The financial power ratings are not favorable for the domestic banks. The third part of the paper focuses on the development directions of the Polish banking sector. It may be concluded on the basis of the analysis that privatisation and consolidation processes will be continued. They will concentrate on the capital of foreign banks already operating in Poland. As compared with individual foreign banks, the potential of the Polish banking sector is week. The fourth part of the paper focuses on the presentation Polish banking sector in the context of European Union banking sector. The paper finishes with conclusions. Generally, Polish banks have to implement a strategy to enable them to compete on the Single

  3. Study on molybdenum base alloy granules fabricated under impulse discharge conditions

    International Nuclear Information System (INIS)

    Myagkov, K.A.; Blinkov, I.V.

    1984-01-01

    The investigation of the structure and properties of alloy granules of the composition Mo-1.2% Ti-0.35%C and Mo-3.1% Ti-0.8%C obtained as a result of titanium and carbon deposition from gas phase on molybdenum powder under impulse discharge conditions is carried out. The alloy granules have been studied by the methods of chemical metallographic and X-ray structural analysis and measured their microhardness and specific surface. It has been found that the deposited elements in case of alloy solidification form fine-dispersed carbide inclusions in matrix metal causing its hardening

  4. Chemical mechanical glass polishing with cerium oxide: Effect of selected physico-chemical characteristics on polishing efficiency

    Czech Academy of Sciences Publication Activity Database

    Janoš, P.; Ederer, J.; Pilařová, V.; Henych, Jiří; Tolasz, Jakub; Milde, D.; Opletal, T.

    2016-01-01

    Roč. 362, SEP (2016), s. 114-120 ISSN 0043-1648 R&D Projects: GA MŠk(CZ) LM2015073 Institutional support: RVO:61388980 Keywords : Chemical mechanical polishing * Ceria-based polishing powders * Polishing efficienc Subject RIV: CA - Inorganic Chemistry Impact factor: 2.531, year: 2016

  5. Nature of active centers and mechanism of metathesis of olefines on supported oxidic catalysts of molybdenum, tungsten and rhenium

    International Nuclear Information System (INIS)

    Kadushin, A.A.; Aliev, R.K.; Krylov, O.V.; Andreev, A.A.; Edreva-Kardzhieva, R.M.; Shopov, D.M.; Bylgarska Akademiya na Naukite, Sofia. Inst. za Obshta i Organichna Khimiya)

    1982-01-01

    A unified model of active centre in metathesis of olefines for oxide catalysts of molybdenum, tungsten and rhenium, supported on aluminium oxide and silica gel, is suggested. A supposition is made that electron transfer from the nearest electron donor through ion of higher valency transition metal to the olefine adsorbed is the main stage of activation process of surface olefine complex. The model is justified by quantum-chemical calculation

  6. The influence of polishing techniques on pre-polymerized CAD\\CAM acrylic resin denture bases.

    Science.gov (United States)

    Alammari, Manal Rahma

    2017-10-01

    Lately, computer-aided design and computer-aided manufacturing (CAD/CAM) has broadly been successfully employed in dentistry. The CAD/CAM systems have recently become commercially available for fabrication of complete dentures, and are considered as an alternative technique to conventionally processed acrylic resin bases. However, they have not yet been fully investigated. The purpose of this study was to inspect the effects of mechanical polishing and chemical polishing on the surface roughness (Ra) and contact angle (wettability) of heat-cured, auto-cured and CAD/CAM denture base acrylic resins. This study was conducted at the Advanced Dental Research Laboratory Center of King Abdulaziz University from March to June 2017. Three denture base materials were selected: heat cure poly-methylmethacrylate resin, thermoplastic (polyamide resin) and (CAD\\CAM) denture base resin. Sixty specimens were prepared and divided into three groups, twenty in each. Each group was divided according to the polishing techniques into (Mech P) and (Chem P), ten specimens in each; surface roughness and wettability were investigated. Data were analyzed by SPSS version 22, using one-way ANOVA and Pearson coefficient. One-way analysis of variance (ANOVA) and post hoc tests were used for comparing the surface roughness values between three groups which revealed a statistical significant difference between them (p 1 CAD\\CAM denture base material (group III) showed the least mean values (1.08±0.23, 1.39±0.31, Mech P and Chem P respectively). CAD/CAM showed the least contact angle in both polishing methods, which were statistically significant at 5% level (p=0.034 and pCAD\\CAM denture base resin with superior smooth surface compared to chemical polishing. Mechanical polishing is considered the best effective polishing technique. CAD/CAM denture base material should be considered as the material of choice for complete denture construction in the near future, especially for older dental

  7. Extraction of workpiece rotary symmetrical error and its deterministic removal by fluid jet polishing

    Science.gov (United States)

    Guo, Zongfu; Jin, Tan; Liu, Qifeng; Lu, Ange; Qu, Meina

    2018-01-01

    Rotary symmetric error (RSE) is a typical type of surface machining errors for precision components, related to the relative tool-workpiece movements adopted. A quick removal method of the workpiece surface RSE using a fluid jet polishing (FJP) process, in which the tool nozzle and workpiece move relatively as in an end-face turning process, is presented. Efficient improvement in the workpiece surface form accuracy was achieved using a relatively simple device. Two methods to extract the RSE from the measured surface error curves, i.e., the average and minimum methods, are introduced and compared. The influence of the local jet rotation radius on the removal function of FJP was investigated experimentally. The algorithm for solving the dwell time curve in two-dimensional FJP process was derived. Deterministic FJP experiments were conducted to remove the RSE by means of the end-face turning movement. Experimental results show that the proportion of the RSE to the overall surface error on most workpieces was reduced from >60% to average RSE extraction method and combining it with the zero-phase filtering method to filter the dwell time can effectively reduce the frequency of residual circular error in the polishing surface and avoid increasing of power spectral density in the mid-high frequency after polishing.

  8. Ion exchange resin fouling of molybdenum in recovery uranium processess

    International Nuclear Information System (INIS)

    Zhang Guowei; Zhao Guirong

    1990-09-01

    The relationship between anion exchange resin fouling and molybdic acid polymerization was studied. By using potentiometer titration and laser-Raman spectroscopy the relationship of molybdic acid polymerization and the pH value of solution or the molybdenum concentration was determined. It was shown that as the concentration of initial molybdenum in solution decreases from 0.2 mol/L to 0.5 mmol/L, the pH value of starting polymerization decreased from 6.5 to 4.5. The experimental results show that the fouling of 201 x 7 resin in the acidic solution is mainly caused by the adsorbing of Mo 3 O 26 4- ion and occupying the exchange radical site of the resin. Under the leaching conditions the molybdenum and phosphate existing in the leaching liquor can form 12-molybdo-phosphate ion. It also leads to resin fouling. The molybdenum on the fouled resin can synergically be desorbed by mixed desorbents containing ammonium hydroxide and ammonium sulfate. The desorbed resin can be used for uranium adsorption and the desorbed molybdenum can be recovered by ion exchange method

  9. Bacterial Colonization in the Marginal Region of Ceramic Restorations: Effects of Different Cement Removal Methods and Polishing.

    Science.gov (United States)

    Pereira, Smb; Anami, L C; Pereira, C A; Souza, Roa; Kantorski, K Z; Bottino, M A; Jorge, Aoc; Valandro, L F

    statistically influenced Ra (MBr, p=0.0019; Br, p=0.002; Photo-Expl, p=0.0262; Photo-SB, p=0.0196) when comparing the polished and unpolished groups. The MBr and MBr-Pol technique differed significantly for CFU/mL values (p=0.010). There was no significant difference in the amounts of biomass and biothickness comparing polished and unpolished groups and when all groups were compared (p>0.05). Different morphological patterns were observed (more regular surface for polished groups). We conclude that margin polishing after cementation of feldspar/pressed ceramic restorations is decisive for achieving smoother surfaces, as the excess cement around the edges can increase the surface roughness in these areas, influencing bacterial adhesion.

  10. Optimized pre-thinning procedures of ion-beam thinning for TEM sample preparation by magnetorheological polishing.

    Science.gov (United States)

    Luo, Hu; Yin, Shaohui; Zhang, Guanhua; Liu, Chunhui; Tang, Qingchun; Guo, Meijian

    2017-10-01

    Ion-beam-thinning is a well-established sample preparation technique for transmission electron microscopy (TEM), but tedious procedures and labor consuming pre-thinning could seriously reduce its efficiency. In this work, we present a simple pre-thinning technique by using magnetorheological (MR) polishing to replace manual lapping and dimpling, and demonstrate the successful preparation of electron-transparent single crystal silicon samples after MR polishing and single-sided ion milling. Dimples pre-thinned to less than 30 microns and with little mechanical surface damage were repeatedly produced under optimized MR polishing conditions. Samples pre-thinned by both MR polishing and traditional technique were ion-beam thinned from the rear side until perforation, and then observed by optical microscopy and TEM. The results show that the specimen pre-thinned by MR technique was free from dimpling related defects, which were still residual in sample pre-thinned by conventional technique. Nice high-resolution TEM images could be acquired after MR polishing and one side ion-thinning. MR polishing promises to be an adaptable and efficient method for pre-thinning in preparation of TEM specimens, especially for brittle ceramics. Copyright © 2017 Elsevier B.V. All rights reserved.

  11. SPECTRAL METHODS IN POLISH EMOTIONAL SPEECH RECOGNITION

    Directory of Open Access Journals (Sweden)

    Paweł Powroźnik

    2016-12-01

    Full Text Available In this article the issue of emotion recognition based on Polish emotional speech signal analysis was presented. The Polish database of emotional speech, prepared and shared by the Medical Electronics Division of the Lodz University of Technology, has been used for research. Speech signal has been processed by Artificial Neural Networks (ANN. The inputs for ANN were information obtained from signal spectrogram. Researches were conducted for three different spectrogram divisions. The ANN consists of four layers but the number of neurons in each layer depends of spectrogram division. Conducted researches focused on six emotional states: a neutral state, sadness, joy, anger, fear and boredom. The averange effectiveness of emotions recognition was about 80%.

  12. Potentiometric titration of molybdenum (6) with a cathode-polarized solid electrode

    International Nuclear Information System (INIS)

    Boeva, L.V.; Kimstach, V.A.; Bagdasarov, K.N.

    1980-01-01

    The possibility has been studied of using solid electrodes for potentiometric precipitation titration of molybdenum (6). A cathode-polarized electrode, electrochemically covered with a molybdenum blue layer, can be used as indicator electrode. The best results were obtained during deposition of molybdenum blue on a tungsten electrode. The mechanism of electrode work during titration has been investigated. A procedure has been developed of titration of molybdenum (6) in acid solutions using hydroxylamine N-aryl derivatives as titrants

  13. Polish 2012 growth references for preschool children.

    Science.gov (United States)

    Kułaga, Zbigniew; Grajda, Aneta; Gurzkowska, Beata; Góźdź, Magdalena; Wojtyło, Małgorzata; Swiąder, Anna; Różdżyńska-Świątkowska, Agnieszka; Litwin, Mieczysław

    2013-06-01

    Growth references are useful in monitoring a child's growth, which is an essential part of child care. The aim of this paper is to provide updated growth references for Polish preschool children and to assess how well children in Poland match or diverge from the World Health Organization (WHO) growth standards/references and recent German height-for-age references. The height-, weight-, body mass index-for-age, and weight-for-height references were constructed with the LMS method using data from a recent, large, population-representative sample of 4,941 preschool children aged 3 to 6 years (the OLA study). In the case of boys, the third, 50th, and 97th height percentiles of new Polish and German references overlap almost completely, whereas the WHO growth standards/references percentiles are systematically lower. In the case of girls, comparison between the new Polish and German height references showed conformity on the third and 50th percentile, whereas body height values of the WHO standards/references are shorter. Polish children aged 3 to 6 years from for the nation representative sample, had significantly greater than zero mean z scores of height-, weight-, and BMI-for-age and weight-for-height, relative to the WHO growth standards/references. The number of children in the sample with height-for-age below -2 SD was significantly lower than expected and number of children with height-for-age above +2 SD was significantly higher than expected. The OLA study growth references can be recommended as national references for preschool children in Poland.

  14. Polish normalization of the Body Esteem Scale

    Directory of Open Access Journals (Sweden)

    Małgorzata Lipowska

    2014-02-01

    Full Text Available Background Physical attractiveness plays an important part in one’s social functioning. The interest in one’s own appearance have been documented as widespread among the female population, but over the recent years it is more and more often emphasized that concentrating on body appearance concerns men as well. Franzoi and Shields (1984 created the Body Esteem Scale which allows to qualify the subject’s attitude towards his or her own body. The aim of the study was to create a Polish version of the Body Esteem Scale along with the norms for age and sex clusters. Participants and procedure The normalization sample consisted of 4298 participants: 1865 women aged 16 to 80 (M = 29.92; SD = 12.85 and 2433 men aged 16 to 78 (M = 28.74; SD = 11.50. Education levels among the participants were also controlled for. In order to create a Polish version of the Body Esteem Scale, translation was adopted as the adaptation strategy. Like the original one, the Polish scale comprises 35 items grouped into three gender specific subscales. The subscales for women include Sexual Attractiveness, Weight Concern, and Physical Condition, whereas the body esteem of is examined with regards to Physical Attractiveness, Upper Body Strength, and Physical Condition. Results Reliability of subscales was high both for females (Cronbach’s alpha from 0.80 to 0.89 and males (Cronbach’s alpha from 0.85 to 0.88. The given coefficients of reliability cover the original division into subscales adopted by the authors of BES. Conclusions We confirmed high reliability of the Polish version of the Body Esteem Scale, thus we recommend it as a diagnostic tool. Created norms allowed to refer results obtained in the course of research carried out on people with various disorders (e.g. eating disorders or body dysmorphic disorder with population data for corresponding age brackets.

  15. Polish Martial Law: The Crisis of Communism

    Science.gov (United States)

    2009-12-01

    Roman Catholic Church continued to exist, and a comparatively liberal cultural policy was in place, which continued a legitimate practice of most of...intervention. Their answers verify that for most Poles the fear 29 of losing sovereignty and Polish culture to Russian aggression overshadows all else, even...they going in? They did not,” Woodrow Wilson International Center for Scholars, http://www.wilsoncenter.org/news/ docs/ Historia -Jachranka%20-%20Stan

  16. Formation of subwavelength grating on molybdenum mirrors using a femtosecond Ti:sapphire laser system operating at 10 Hz.

    Science.gov (United States)

    Sharma, Avnish Kumar; Smedley, John; Tsang, Thomas; Rao, Triveni

    2011-03-01

    We report formation of subwavelength surface grating over large surface area of molybdenum mirror by multiple irradiation of amplified femtosecond laser pulses from a homemade Ti:sapphire oscillator-amplifier laser system in a raster scan configuration. The laser system delivered 2 mJ, 80 fs duration laser pulses at a pulse repetition rate of 10 Hz. Various parameters such as pulse fluence, number of pulses, laser polarization, scan speed, and scan steps were optimized to obtain uniform subwavelength gratings. Energy dispersive x-ray spectroscopy measurements were conducted to analyze the elemental composition of mirror surfaces before and after laser treatment.

  17. The Polish Cyborg. A Reflection on the Relationship between Man and Machine in Early Polish Modernism

    Directory of Open Access Journals (Sweden)

    Emiliano Ranocchi

    2016-12-01

    Full Text Available Far from being enthusiastic “modernolatry” of Italian futurism, Polish futurism demonstrates an attitude of ambivalence toward modernity. This is particularly evident in the Polish approach to that very synecdoche of modernity which is the machine. In his essay of 1923, the leader of the group, Bruno Jasieński, compares the fetishistic cult of the machine, which characterizes the Italian approach, with the utilitarian one of the Russians, exemplified by a quote from Majakovskij. To these two propositions, as a sort of Hegelian synthesis, he adds a Polish one consisting in the conception of the machine as a prosthesis, a continuation of the human body. Thereby he introduces an idea later known as “cyborg”. The category of cyborg is also useful to understand the work of another today almost forgotten Polish writer of the Twenties, Jerzy Sosnkowski. He was the author of a short novel, A Car, You and Me (Love of Machines, in which a whole chapter concerns the chief character’s dystopian nightmare wherein machines take control over the world. The third section of the essay deals with the idea of man a machine – an old, 18th century conception, which became actual anew in the 20th century and whose traces we can find among others in a well-known poem by Tytus Czyżewski. Thirty years before N. Wiener, Polish modernists seem to have sensed the social, political and anthropological implications of the mechanization of work.

  18. The behaviour of molybdenum dialkyldithiocarbamate friction modifier additives

    CERN Document Server

    Graham, J C H

    2001-01-01

    In recent years there has been growing concern to produce energy-efficient lubricated components and modem engine oil specifications require lubricants to demonstrate fuel efficiency in standardised engine tests. One important method of producing low friction and thus fuel-efficient lubricants is to use oil-soluble, molybdenum-containing, friction modifier additives. In optimal conditions these additives are able to produce very low friction coefficients, in the range 0.045 to 0.075 in boundary lubrication conditions. Very little is known about the chemical and physical mechanisms by which oil soluble molybdenum additives form low friction films in tribological contacts. Information about their activity could lead to optimal use of these additives in lubricants and, therefore, more efficient engine running. The work outlined in this thesis investigated the behaviour of oil-soluble molybdenum additives and showed that these additives were able to effectively reduce friction in the absence of other additives su...

  19. Supported molybdenum carbide for higher alcohol synthesis from syngas

    DEFF Research Database (Denmark)

    Wu, Qiongxiao; Christensen, Jakob Munkholt; Chiarello, Gian Luca

    2013-01-01

    carbide, while the selectivity to methanol follows the opposite trend. The effect of Mo2C loading on the alcohol selectivity at a fixed K/Mo molar ratio of 0.14 could be related to the amount of K2CO3 actually on the active Mo2C phase and the size, structure and composition of the supported carbide......Molybdenum carbide supported on active carbon, carbon nanotubes, and titanium dioxide, and promoted by K2CO3, has been prepared and tested for methanol and higher alcohol synthesis from syngas. At optimal conditions, the activity and selectivity to alcohols (methanol and higher alcohols) over...... supported molybdenum carbide are significantly higher compared to the bulk carbide. The CO conversion reaches a maximum, when about 20wt% Mo2C is loaded on active carbon. The selectivity to higher alcohols increases with increasing Mo2C loading on active carbon and reaches a maximum over bulk molybdenum...

  20. Molybdenum chloride catalysts for Z-selective olefin metathesis reactions

    Science.gov (United States)

    Koh, Ming Joo; Nguyen, Thach T.; Lam, Jonathan K.; Torker, Sebastian; Hyvl, Jakub; Schrock, Richard R.; Hoveyda, Amir H.

    2017-01-01

    The development of catalyst-controlled stereoselective olefin metathesis processes has been a pivotal recent advance in chemistry. The incorporation of appropriate ligands within complexes based on molybdenum, tungsten and ruthenium has led to reactivity and selectivity levels that were previously inaccessible. Here we show that molybdenum monoaryloxide chloride complexes furnish higher-energy (Z) isomers of trifluoromethyl-substituted alkenes through cross-metathesis reactions with the commercially available, inexpensive and typically inert Z-1,1,1,4,4,4-hexafluoro-2-butene. Furthermore, otherwise inefficient and non-stereoselective transformations with Z-1,2-dichloroethene and 1,2-dibromoethene can be effected with substantially improved efficiency and Z selectivity. The use of such molybdenum monoaryloxide chloride complexes enables the synthesis of representative biologically active molecules and trifluoromethyl analogues of medicinally relevant compounds. The origins of the activity and selectivity levels observed, which contradict previously proposed principles, are elucidated with the aid of density functional theory calculations.

  1. Molybdenum cofactor deficiency mimics cerebral palsy: differentiating factors for diagnosis.

    Science.gov (United States)

    Kikuchi, Kenjiro; Hamano, Shin-ichiro; Mochizuki, Hiroshi; Ichida, Kimiyoshi; Ida, Hiroyuki

    2012-08-01

    We describe an infant with molybdenum cofactor deficiency, initially diagnosed as cerebral palsy. Clinical features of molybdenum cofactor deficiency, e.g., neonatal seizures, hypertonus/hypotonus, and feeding and respiratory difficulties, resemble those of neonatal hypoxic-ischemic encephalopathy. Our patient, a 2-year-old boy, presented with spastic quadriplegia and mental retardation. He manifested intractable neonatal seizures and diffuse cerebral atrophy. When admitted with bronchitis at age 18 months, his uric acid levels in blood and urine were undetectable. A urinary sulfite test revealed positive results. Further tests revealed elevated urinary levels of xanthine, hypoxanthine, and S-sulfocystein. Sequencing of the MOCS2A gene revealed heterozygosity for c.[265T>C] + [266A>G], diagnosed as molybdenum cofactor deficiency type B. Neonatal seizures, progressive cerebral atrophy, and low serum levels of uric acid may provide diagnostic clues in patients with cerebral palsy of undetermined cause. Copyright © 2012 Elsevier Inc. All rights reserved.

  2. A molybdenum disulfide/carbon nanotube heterogeneous complementary inverter.

    Science.gov (United States)

    Huang, Jun; Somu, Sivasubramanian; Busnaina, Ahmed

    2012-08-24

    We report a simple, bottom-up/top-down approach for integrating drastically different nanoscale building blocks to form a heterogeneous complementary inverter circuit based on layered molybdenum disulfide and carbon nanotube (CNT) bundles. The fabricated CNT/MoS(2) inverter is composed of n-type molybdenum disulfide (MOS(2)) and p-type CNT transistors, with a high voltage gain of 1.3. The CNT channels are fabricated using directed assembly while the layered molybdenum disulfide channels are fabricated by mechanical exfoliation. This bottom-up fabrication approach for integrating various nanoscale elements with unique characteristics provides an alternative cost-effective methodology to complementary metal-oxide-semiconductors, laying the foundation for the realization of high performance logic circuits.

  3. Effects of polishing procedures on color stability of composite resins.

    Science.gov (United States)

    Güler, Ahmet Umut; Güler, Eda; Yücel, Ali Cağin; Ertaş, Ertan

    2009-01-01

    The purpose of this study was to investigate the effect of different polishing methods on color stability of posterior, universal and nanohybrid composite resin restorative materials upon exposure to a staining agent. Twenty-five specimens were prepared for each of 5 different composite resins (Filtek Z250, Filtek P60, Quadrant LC, Grandio and Filtek Supreme). Specimens were divided into 5 groups and different polishing procedures, including polishing discs (Pd), polishing discs then diamond polishing paste (PdP), polishing discs then a liquid polishing system (Biscover) (PdB), and combinations of these (PdPB) were used. Unpolished specimens served as the control (C). The specimens were stored for 48 h in a coffee solution. The color of all specimens was measured before and after exposure with a colorimeter, and total color change (DeltaE*) were calculated. The data were analyzed with a two-way ANOVA and the means were compared by Tukey HSD test (alpha=0.05). The lowest color difference was observed in the groups PdP and C, while the highest color difference was observed in PdPB, and PdB. When comparing the five different restorative materials, no significant difference was observed between FiltekP60 and FiltekZ250, and these materials demonstrated significantly less color change than Quadrant LC and the nanohybrid materials (Grandio, Filtek Supreme). The posterior (Filtek P60) and universal (Filtek Z250) composite resin restorative materials, which do not contain tetraethyleneglycol dimethacrylate (TEGDMA), were found to be less stainable than the nanohybrid (Grandio, Filtek Supreme) and universal (Quadrant LC) composite resins, which contain TEGDMA. The use of diamond polishing paste after polishing with polishing discs significantly decreased staining when compared to the groups that used polishing discs alone, for all restorative materials tested. The highest color change values were obtained for the specimens that were polished with the Biscover liquid polish

  4. Effects of polishing procedures on color stability of composite resins

    Directory of Open Access Journals (Sweden)

    Ahmet Umut Güler

    2009-04-01

    Full Text Available The purpose of this study was to investigate the effect of different polishing methods on color stability of posterior, universal and nanohybrid composite resin restorative materials upon exposure to a staining agent. Twenty-five specimens were prepared for each of 5 different composite resins (Filtek Z250, Filtek P60, Quadrant LC, Grandio and Filtek Supreme. Specimens were divided into 5 groups and different polishing procedures, including polishing discs (Pd, polishing discs then diamond polishing paste (PdP, polishing discs then a liquid polishing system (Biscover (PdB, and combinations of these (PdPB were used. Unpolished specimens served as the control (C. The specimens were stored for 48 h in a coffee solution. The color of all specimens was measured before and after exposure with a colorimeter, and total color change (DE* were calculated. The data were analyzed with a two-way ANOVA and the means were compared by Tukey HSD test (a=0.05. The lowest color difference was observed in the groups PdP and C, while the highest color difference was observed in PdPB, and PdB. When comparing the five different restorative materials, no significant difference was observed between FiltekP60 and FiltekZ250, and these materials demonstrated significantly less color change than Quadrant LC and the nanohybrid materials (Grandio, Filtek Supreme. The posterior (Filtek P60 and universal (Filtek Z250 composite resin restorative materials, which do not contain tetraethyleneglycol dimethacrylate (TEGDMA, were found to be less stainable than the nanohybrid (Grandio, Filtek Supreme and universal (Quadrant LC composite resins, which contain TEGDMA. The use of diamond polishing paste after polishing with polishing discs significantly decreased staining when compared to the groups that used polishing discs alone, for all restorative materials tested. The highest color change values were obtained for the specimens that were polished with the Biscover liquid polish

  5. Preparation and chemical characterization of neodymium-doped molybdenum oxide films grown using spray pyrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Alfonso, J. E. [Universidad Nacional de Colombia, Departamento de Fisica, Grupo de Ciencia Materiales y Superficies, AA 5997 Bogota DC (Colombia); Moreno, L. C., E-mail: jealfonsoo@unal.edu.co [Universidad Nacional de Colombia, Departamento de Quimica, AA 5997 Bogota DC (Colombia)

    2014-07-01

    We studied the crystalline, morphology, and surface composition of Nd-doped molybdenum oxide films grown on glass slides through spray pyrolysis. After fabrication, the films were subjected to thermal treatment in oxygen for periods ranging from 2 to 20 hours. The films were structurally characterized though X-ray diffraction (XRD), their bulk chemical composition was determined using Energy-Dispersive X-ray analysis (EDX), and their surface composition was determined using X-ray Photoelectron Spectroscopy (XP S). The XRD results show that the films obtained from different dissolution volumes and at substrate temperature of 300 grades C exhibit the characteristics of the oxygen-deficient molybdenum trioxide Mo{sub 9}O{sub 26} phase. The films subjected to different thermal treatments exhibit a mixture of Mo{sub 9}O{sub 26} and Mo{sub 17}O{sub 47} phases. EDX study shows the energy belonging to the L line of Nd. Finally, films doped with Nd and subjected to a thermal treatment of 20 h were analyzed through XP S, showing the binding energies at the crystalline lattice correspond to Nd{sub 2} (MoO{sub 4}){sub 3} and Nd{sub 2}Mo{sub 2}O{sub 7}. (Author)

  6. A High-Power Test of an X-Band Molybdenum-Iris Structure

    CERN Document Server

    Wuensch, Walter; Grudiev, A; Heikkinen, Samuli Tapio; Syratchev, I V; Taborelli, M; Wilson, Ian H; Adolphsen, C E

    2004-01-01

    In order to achieve accelerating gradients above 150 MV/m, alternative materials to copper are being investigated by the CLIC study. The potential of refractory metals has already been demonstrated in tests in which a tungsten-iris and a molybdenum-iris structure reached 150 and 193 MV/m respectively (30 GHz and a pulse length of 15 ns). In order to extend the investigation to the pulse lengths required for a linear collider, a molybdenum-iris structure scaled to X-band was tested at the Next Linear Collider Test Accelerator (NLCTA). The structure conditioned to only 65 MV/m (100 ns pulse length) in the available testing time and much more slowly than is typical of a copper structure. However the structure showed no sign of saturation and a microscopic inspection of the rf surfaces corroborated that the structure was still at an early stage of conditioning. The X-band and 30 GHz results are compared and what has been learned about material quality, surface preparation and conditioning strategy is discussed.

  7. Molybdenum phosphosulfide: an active, acid-stable, earth-abundant catalyst for the hydrogen evolution reaction.

    Science.gov (United States)

    Kibsgaard, Jakob; Jaramillo, Thomas F

    2014-12-22

    Introducing sulfur into the surface of molybdenum phosphide (MoP) produces a molybdenum phosphosulfide (MoP|S) catalyst with superb activity and stability for the hydrogen evolution reaction (HER) in acidic environments. The MoP|S catalyst reported herein exhibits one of the highest HER activities of any non-noble-metal electrocatalyst investigated in strong acid, while remaining perfectly stable in accelerated durability testing. Whereas mixed-metal alloy catalysts are well-known, MoP|S represents a more uncommon mixed-anion catalyst where synergistic effects between sulfur and phosphorus produce a high-surface-area electrode that is more active than those based on either the pure sulfide or the pure phosphide. The extraordinarily high activity and stability of this catalyst open up avenues to replace platinum in technologies relevant to renewable energies, such as proton exchange membrane (PEM) electrolyzers and solar photoelectrochemical (PEC) water-splitting cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. The role of oxygen and water on molybdenum nanoclusters for electro catalytic ammonia production

    DEFF Research Database (Denmark)

    Howalt, Jakob Geelmuyden; Vegge, Tejs

    2014-01-01

    The presence of water often gives rise to oxygen adsorption on catalyst surfaces through decomposition of water and the adsorbed oxygen or hydroxide species often occupy important surfaces sites, resulting in a decrease or a total hindrance of other chemical reactions taking place at that site...... are -0.72 V or lower for all oxygen coverages studied, and it is thus possible to (re)activate (partially) oxidized nanoclusters for electrochemical ammonia production, e.g., using a dry proton conductor or an aqueous electrolyte. At lower oxygen coverages, nitrogen molecules can adsorb to the surface....... In this study, we present theoretical investigations of the influence of oxygen adsorption and reduction on pure and nitrogen covered molybdenum nanocluster electro catalysts for electrochemical reduction of N2 to NH3 with the purpose of understanding oxygen and water poisoning of the catalyst. Density...

  9. Molybdenum--substrate interactions in nitrogenase: an EXAFS study

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J.P.

    1978-07-01

    The sensitivity of x-ray absorption edge spectra and extended x-ray absorption fine structure (EXAFS) to the environment of metal atoms make x-ray absorption spectroscopy a useful probe of the environment of the molybdenum in nitrogenase. It is of particular interest to investigate any perturbations of the environment of the molybdenum due to the presence of nitrogenase substrates. The results of measurements of the x-ray absorption spectra of nitrogenase samples by the absorption and fluorescence detection techniques are compared. The procedures used for the growth of Azotobacter vinelandii for the production of nitrogenase and the procedures used for the purification of nitrogenase are described in detail.

  10. Recovery of uranium from sulphate solutions containing molybdenum

    International Nuclear Information System (INIS)

    Weir, D.R.; Genik-Sas-Berezowsky, R.M.

    1983-01-01

    A process for recovering uranium from a sulphate solution containing dissolved uranium and molybdenum includes reacting the solution with ammonia (pH 8 to 10), the pH of the original solution must not exceed 5.5 and after the addition of ammonia the pH must not be in the vicinity of 7 for a significant time. The resultant uranium precipitate is relatively uncontaminated by molybdenum. The precipitate is then separated from the remaining solution while the pH is maintained within the stated range

  11. Study of the solubility of molybdenum in nitric solutions

    International Nuclear Information System (INIS)

    Faugeras, P.; Lheureux, C.; Leroy, P.

    1961-01-01

    The use of U-Mo alloys in reactors poses naturally the problem of the chemical treatment of these nuclear fuels. The molybdenum is scarcely soluble in the nitric solutions used during this treatment, and may precipitate during these operations. In order to forestall these incidents, we have made a study of the solubility of molybdenum as a function of temperature, of the acidity, and of the uranium concentration. We have also studied the influence of the presence of ferric ions on this solubility. (author) [fr

  12. An Oxygen-Insensitive Hydrogen Evolution Catalyst Coated by a Molybdenum-Based Layer for Overall Water Splitting

    KAUST Repository

    Garcia Esparza, Angel T.

    2017-04-13

    For overall water-splitting systems, it is essential to establish O2 -insensitive cathodes that allow cogeneration of H2 and O2 . An acid-tolerant electrocatalyst is described, which employs a Mo-coating on a metal surface to achieve selective H2 evolution in the presence of O2 . In operando X-ray absorption spectroscopy identified reduced Pt covered with an amorphous molybdenum oxyhydroxide hydrate with a local structural order composed of polyanionic trimeric units of molybdenum(IV). The Mo layer likely hinders O2 gas permeation, impeding contact with active Pt. Photocatalytic overall water splitting proceeded using MoOx /Pt/SrTiO3 with inhibited water formation from H2 and O2 , which is the prevailing back reaction on the bare Pt/SrTiO3 photocatalyst. The Mo coating was stable in acidic media for multiple hours of overall water splitting by membraneless electrolysis and photocatalysis.

  13. Growth and shape of indium islands on molybdenum at micro-roughened spots created by femtosecond laser pulses

    Science.gov (United States)

    Ringleb, F.; Eylers, K.; Teubner, Th.; Schramm, H.-P.; Symietz, C.; Bonse, J.; Andree, S.; Heidmann, B.; Schmid, M.; Krüger, J.; Boeck, T.

    2017-10-01

    Indium islands on molybdenum coated glass can be grown in ordered arrays by surface structuring using a femtosecond laser. The effect of varying the molybdenum coated glass substrate temperature and the indium deposition rate on island areal density, volume and geometry is investigated and evaluated in a physical vapor deposition (PVD) process. The joined impact of growth conditions and spacing of the femtosecond laser structured spots on the arrangement and morphology of indium islands is demonstrated. The results yield a deeper understanding of the island growth and its precise adjustment to industrial requirements, which is indispensable for a technological application of such structures at a high throughput, for instance as precursors for the preparation of Cu(In,Ga)Se2 micro concentrator solar cells.

  14. Effects of neutron irradiation on microstructure and deformation behaviour of mono- and polycrystalline molybdenum and its alloys

    DEFF Research Database (Denmark)

    Singh, B.N.; Evans, J.H.; Horsewell, A.

    1998-01-01

    The influence of neutron irradiation on microstructural evolution and mechanical properties of mono- and polycrystalline molybdenum and its alloys has been investigated. Tensile specimens and 3 mm diameter discs of monocrystals of pure molybdenum and Mo-5%Re were irradiated with fission neutrons...... specimens were tensile tested at 295 K. Post-irradiation microstructures were quantitatively characterized using a transmission electron microscope (TEM). Fracture surfaces were examined in a scanning electron microscope (SEM). The results of tensile testing as well as of transmission and scanning...... microscopy are presented and discussed in terms of intracascade clustering of self-interstitial atoms and the role of one-dimensional glide of these clusters in controlling microstructural evolution and the resulting mechanical properties....

  15. Macrophages adhesion rate on Ti-6Al-4V substrates: polishing and DLC coating effects

    Directory of Open Access Journals (Sweden)

    Everton Diniz dos Santos

    Full Text Available Abstract Introduction Various works have shown that diamond-like carbon (DLC coatings are able to improve the cells adhesion on prosthesis material and also cause protection against the physical wear. On the other hand there are reports about the effect of substrate polishing, in evidence of that roughness can enhance cell adhesion. In order to compare and quantify the joint effects of both factors, i.e, polishing and DLC coating, a commonly prosthesis material, the Ti-6Al-4V alloy, was used as raw material for substrates in our studies of macrophage cell adhesion rate on rough and polished samples, coated and uncoated with DLC. Methods The films were produced by PECVD technique on Ti-6Al-4V substrates and characterized by optical profilometry, scanning electron microscopy and Raman spectroscopy. The amount of cells was measured by particle analysis in IMAGE J software. Cytotoxicity tests were also carried out to infer the biocompatibility of the samples. Results The results showed that higher the surface roughness of the alloy, higher are the cells fixing on the samples surface, moreover group of samples with DLC favored the cell adhesion more than their respective uncoated groups. The cytotoxity tests confirmed that all samples were biocompatible independently of being polished or coated with DLC. Conclusion From the observed results, it was found that the rougher substrate coated with DLC showed a higher cell adhesion than the polished samples, either coated or uncoated with the film. It is concluded that the roughness of the Ti-6Al-4V alloy and the DLC coating act complementary to enhance cell adhesion.

  16. Finishing and polishing of the ceromer material Targis. Lab-side and chair-side methods.

    Science.gov (United States)

    Behr, M; Rosentritt, M; Leibrock, A; Schneider-Feyrer, S; Handel, G

    1999-01-01

    The aim of the study was to check four lab-side and four chair-side methods for finishing and polishing the ceromer material Targis. Eighty bar-shaped specimens (20 mm x 10 mm x 2 mm) of Vectris were produced; 72 were covered with a 2 mm (thickness) layer of the Ceromer Targis and eight samples with the composite Tetric. All specimens were ground plane parallel with 320 Silicium carbide grit sandpaper in order to start with the same level of roughness. Then the specimens were finished and polished using the following methods: (1) Artglass toolkit, (2) pumice-stone and brushes/linen brush and polishing paste P3, (3) Robinson brush/Ivoclar Universal paste and wool brush, (4) Silicone wheel and rag wheel, (5) Shofu Rainbow set, (6) Sof-Lex discs, (7) Vivadent Politip set and (8) Nupro-pastes and brushes. The surface roughness was determined with a profilometer. The arithmetical roughness value Ra was calculated. From each group one specimen was randomly chosen and sputtered with gold in order to observe the surface with a scanning electron microscope to evaluate its smoothness. The methods were ranked as followed: 2, 3 and 5 with the lowest roughness, then 8, 6, 7, 4, 1. The best ranked chair-side method (5) and the best ranked lab-side methods (2, 3) did not differ significantly between the Ra values. No difference was observed between the composite Tetric and the ceromer Targis when these materials were polished using the same method. the lab-side-methods 2 and 3 and the chair-side-method 5 can be recommended for finishing and polishing the new ceromer material Targis.

  17. Comparison of ceria nanoparticle concentrations in effluent from chemical mechanical polishing of silicon dioxide.

    Science.gov (United States)

    Zazzera, Larry; Mader, Brian; Ellefson, Mark; Eldridge, Jess; Loper, Steve; Zabasajja, John; Qian, Julie

    2014-11-18

    This work measured and compared the effluent from the chemical mechanical polishing (CMP) of silicon dioxide using ceria slurry and ceria fixed abrasive. CMP waste streams were tested for total solids, cerium, silicon, and 6 nm to 20 μm diameter particles. The concentration of cerium and total solids in the effluent were very different for the two polishes studied. The fixed abrasive polish produced 94% less CeO2 emissions per SiO2 removed. The higher ceria levels in the slurry effluent are associated with 99-279 nm particles, and attributed to ceria abrasive. The lower concentration of ceria in the effluent from the fixed abrasive process is due to the lower wear rate of mineral from the fixed abrasive, compared to the more environmentally mobile mineral in the slurry. These results support the "bonded" nature of the abrasive particles in fixed abrasive polishing and are relevant to sustainability strategies that seek to reduce particle emissions in surface conditioning technology.

  18. An inverse-polished mirror for wavefront correction of space-based telescopes

    Science.gov (United States)

    Enya, K.; Haze, K.; Chibu, Y.; Kotani, T.; Kaneda, H.; Oyabu, S.; Ishihara, D.; Oseki, S.; Abe, L.; Kobayashi, H.

    2014-07-01

    In this report we describe our development of a prototype inverse-polished mirror for the passive correction of the static and predictable wavefront errors (WFE) of space-based telescopes, in particular, especially for infrared coronagraphs. An artificial WFE pattern with a root mean square (rms) value of 350 nm was numerically generated to facilitate the design of the prototype mirror. The surface of the mirror is approximately flat, is 50.0 mm in diameter and 15.0 mm thick at the edge. The designed WFE pattern was constructed on the mirror surface by micro-polishing. Both the figure and roughness of the mirror surface were evaluated. The rms value of the measured surface figure was reduced to 135 nm after subtraction of the designed surface figure. The benefit of subtraction to mid-infrared coronagraph performance was simulated, which showed the contrast was improved by a factor of ~100 close to the core (closer than 10 λ/D where λ and D are the wavelength and telescope aperture diameter, respectively) of the coronagraphic image of a point source. An analysis of the power spectrum density shows that the lower frequencies in the WFE are well reproduced on the mirror, while the higher frequencies remain due to the limitations imposed on the controllable spatial resolution by the fabrication process. In this study, inverse-polished mirrors combined with deformable mirrors and their application to ground-based telescopes are also discussed. To fully explore the potential of the inverse-polished mirror, a systematic allocation of the error budget is essential taking into account not only the fabrication accuracy of the mirror but also an evaluation of the telescope and other factors with non-predictable uncertainties.

  19. Hydrodynamic modelling in the Polish Zone of the Baltic Sea - an overview of Polish achievements

    Directory of Open Access Journals (Sweden)

    Ewa Jasińska

    2003-03-01

    Full Text Available This paper gives a general overview of Polish experience and achievements with regard to hydrodynamic modelling in the Polish zone of the Baltic Sea. The first work started already at the end of the sixties when the first 1D and 2D hydrodynamic models were set up. With the development of numerical methods and increasing computational power a number of 1D, 2D and 3D models were set up and tested. Global, regional and local models cover the most important water bodies,i.e. the Pomeranian Bay - Szczecin Lagoon and Gulf of Gdansk - Vistula Lagoon systems.

  20. Cleavage and formation of molecular dinitrogen in a single system assisted by molybdenum complexes bearing ferrocenyldiphosphine.

    Science.gov (United States)

    Miyazaki, Takamasa; Tanaka, Hiromasa; Tanabe, Yoshiaki; Yuki, Masahiro; Nakajima, Kazunari; Yoshizawa, Kazunari; Nishibayashi, Yoshiaki

    2014-10-20

    The N≡N bond of molecular dinitrogen bridging two molybdenum atoms in the pentamethylcyclopentadienyl molybdenum complexes that bear ferrocenyldiphosphine as an auxiliary ligand is homolytically cleaved under visible light irradiation at room temperature to afford two molar molybdenum nitride complexes. Conversely, the bridging molecular dinitrogen is reformed by the oxidation of the molybdenum nitride complex at room temperature. This result provides a successful example of the cleavage and formation of molecular dinitrogen induced by a pair of two different external stimuli using a single system assisted by molybdenum complexes bearing ferrocenyldiphosphine under ambient conditions. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.