Ultraprecision finishing of micro-aspherical surface by ultrasonic assisted polishing; Technical Digest

NASA Astrophysics Data System (ADS)

Suzuki, Hirofumi; Kawamori, Ryota; Yamamoto, Yuji; Miyabara, Mitsuru; Okino, Tadashi; Hijikata, Yoshio; Moriwaki, Toshimichi

2005-05-01

Micro aspherical glass lenses are required for electronic devices, optical devices and advanced optical fiber transmission equipments. The glass lenses are manufactured by glass molding method by using micro ceramics dies such as tungsten carbide or silicon carbide (1). Therefore molding dies are most important and they were ground by ultra-precision grinding method with diamond wheel. Recently, the wavelength of used laser is becoming shorter and then the accuracies of the micro molding die are required to be much more precise (2). In this paper, ultrasonic assisted polishing methods/systems were developed in order to finish micro aspherical dies that were ground with micro diamond wheel. In the polishing experiments, the molding die of tungsten carbide was polished with diamond abrasives to test the basic polishing characteristics and the aspheric die was polished with proposed ultrasonic assisted polishing method.

Manufacturing aspheric mirrors made of zero thermal expansion cordierite ceramics using Magnetorheological Finishing (MRF)

NASA Astrophysics Data System (ADS)

Sugawara, Jun; Maloney, Chris

2016-07-01

NEXCERATM cordierite ceramics, which have ultra-low thermal expansion properties, are perfect candidate materials to be used for light-weight satellite mirrors that are used for geostationary earth observation and for mirrors used in ground-based astronomical metrology. To manufacture the high precision aspheric shapes required, the deterministic aspherization and figure correction capabilities of Magnetorheological Finishing (MRF) are tested. First, a material compatibility test is performed to determine the best method for achieving the lowest surface roughness of RMS 0.8nm on plano surfaces made of NEXCERATM ceramics. Secondly, we will use MRF to perform high precision figure correction and to induce a hyperbolic shape into a conventionally polished 100mm diameter sphere.

The topographic development and areal parametric characterization of a stratified surface polished by mass finishing

NASA Astrophysics Data System (ADS)

Walton, Karl; Blunt, Liam; Fleming, Leigh

2015-09-01

Mass finishing is amongst the most widely used finishing processes in modern manufacturing, in applications from deburring to edge radiusing and polishing. Processing objectives are varied, ranging from the cosmetic to the functionally critical. One such critical application is the hydraulically smooth polishing of aero engine component gas-washed surfaces. In this, and many other applications the drive to improve process control and finish tolerance is ever present. Considering its widespread use mass finishing has seen limited research activity, particularly with respect to surface characterization. The objectives of the current paper are to; characterise the mass finished stratified surface and its development process using areal surface parameters, provide guidance on the optimal parameters and sampling method to characterise this surface type for a given application, and detail the spatial variation in surface topography due to coupon edge shadowing. Blasted and peened square plate coupons in titanium alloy are wet (vibro) mass finished iteratively with increasing duration. Measurement fields are precisely relocated between iterations by fixturing and an image superimposition alignment technique. Surface topography development is detailed with ‘log of process duration’ plots of the ‘areal parameters for scale-limited stratified functional surfaces’, (the Sk family). Characteristic features of the Smr2 plot are seen to map out the processing of peak, core and dale regions in turn. These surface process regions also become apparent in the ‘log of process duration’ plot for Sq, where lower core and dale regions are well modelled by logarithmic functions. Surface finish (Ra or Sa) with mass finishing duration is currently predicted with an exponential model. This model is shown to be limited for the current surface type at a critical range of surface finishes. Statistical analysis provides a group of areal parameters including; Vvc, Sq, and Sdq

Surface Finish after Laser Metal Deposition

NASA Astrophysics Data System (ADS)

Rombouts, M.; Maes, G.; Hendrix, W.; Delarbre, E.; Motmans, F.

Laser metal deposition (LMD) is an additive manufacturing technology for the fabrication of metal parts through layerwise deposition and laser induced melting of metal powder. The poor surface finish presents a major limitation in LMD. This study focuses on the effects of surface inclination angle and strategies to improve the surface finish of LMD components. A substantial improvement in surface quality of both the side and top surfaces has been obtained by laser remelting after powder deposition.

Fabrication of high precision metallic freeform mirrors with magnetorheological finishing (MRF)

NASA Astrophysics Data System (ADS)

Beier, Matthias; Scheiding, Sebastian; Gebhardt, Andreas; Loose, Roman; Risse, Stefan; Eberhardt, Ramona; Tünnermann, Andreas

2013-09-01

The fabrication of complex shaped metal mirrors for optical imaging is a classical application area of diamond machining techniques. Aspherical and freeform shaped optical components up to several 100 mm in diameter can be manufactured with high precision in an acceptable amount of time. However, applications are naturally limited to the infrared spectral region due to scatter losses for shorter wavelengths as a result of the remaining periodic diamond turning structure. Achieving diffraction limited performance in the visible spectrum demands for the application of additional polishing steps. Magnetorheological Finishing (MRF) is a powerful tool to improve figure and finish of complex shaped optics at the same time in a single processing step. The application of MRF as a figuring tool for precise metal mirrors is a nontrivial task since the technology was primarily developed for figuring and finishing a variety of other optical materials, such as glasses or glass ceramics. In the presented work, MRF is used as a figuring tool for diamond turned aluminum lightweight mirrors with electroless nickel plating. It is applied as a direct follow-up process after diamond machining of the mirrors. A high precision measurement setup, composed of an interferometer and an advanced Computer Generated Hologram with additional alignment features, allows for precise metrology of the freeform shaped optics in short measuring cycles. Shape deviations less than 150 nm PV / 20 nm rms are achieved reliably for freeform mirrors with apertures of more than 300 mm. Characterization of removable and induced spatial frequencies is carried out by investigating the Power Spectral Density.

NCMS PWB Surface Finishes Team project summary

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

Kokas, J.; DeSantis, C.; Wenger, G.

1996-04-01

The NCMS PWB Surface Finishes Consortium is just about at the end of the five year program. Dozens of projects related to surface finishes and PWB solder-ability were performed by the team throughout the program, and many of them are listed in this paper. They are listed with a cross reference to where and when a technical paper was presented describing the results of the research. However, due to time and space constraints, this paper can summarize the details of only three of the major research projects accomplished by the team. The first project described is an ``Evaluation of PWBmore » Surface Finishes.`` It describes the solderability, reliability, and wire bondability of numerous surface finishes. The second project outlined is an ``Evaluation of PWB Solderability Test Methods.`` The third project outlined is the ``Development and Evaluation of Organic Solderability Preservatives.``« less

Ultra-precision turning of complex spiral optical delay line

NASA Astrophysics Data System (ADS)

Zhang, Xiaodong; Li, Po; Fang, Fengzhou; Wang, Qichang

2011-11-01

Optical delay line (ODL) implements the vertical or depth scanning of optical coherence tomography, which is the most important factor affecting the scanning resolution and speed. The spinning spiral mirror is found as an excellent optical delay device because of the high-speed and high-repetition-rate. However, it is one difficult task to machine the mirror due to the special shape and precision requirement. In this paper, the spiral mirror with titled parabolic generatrix is proposed, and the ultra-precision turning method is studied for its machining using the spiral mathematic model. Another type of ODL with the segmental shape is also introduced and machined to make rotation balance for the mass equalization when scanning. The efficiency improvement is considered in details, including the rough cutting with the 5- axis milling machine, the machining coordinates unification, and the selection of layer direction in turning. The onmachine measuring method based on stylus gauge is designed to analyze the shape deviation. The air bearing is used as the measuring staff and the laser interferometer sensor as the position sensor, whose repeatability accuracy is proved up to 10nm and the stable feature keeps well. With this method developed, the complex mirror with nanometric finish of 10.7nm in Ra and the form error within 1um are achieved.

Aspects of ultra-high-precision diamond machining of RSA 443 optical aluminium

NASA Astrophysics Data System (ADS)

Mkoko, Z.; Abou-El-Hossein, K.

2015-08-01

Optical aluminium alloys such as 6061-T6 are traditionally used in ultra-high precision manufacturing for making optical mirrors for aerospace and other applications. However, the optics industry has recently witnessed the development of more advanced optical aluminium grades that are capable of addressing some of the issues encountered when turning with single-point natural monocrystalline diamond cutters. The advent of rapidly solidified aluminium (RSA) grades has generally opened up new possibilities for ultra-high precision manufacturing of optical components. In this study, experiments were conducted with single-point diamond cutters on rapidly solidified aluminium RSA 443 material. The objective of this study is to observe the effects of depth of cut and feed rate at a fixed rotational speed on the tool wear rate and resulting surface roughness of diamond turned specimens. This is done to gain further understanding of the rate of wear on the diamond cutters versus the surface texture generated on the RSA 443 material. The diamond machining experiments yielded machined surfaces which are less reflective but with consistent surface roughness values. Cutting tools were observed for wear through scanning microscopy; relatively low wear pattern was evident on the diamond tool edge. The highest tool wear were obtained at higher depth of cut and increased feed rate.

Effect of Burnishing Parameters on Surface Finish

NASA Astrophysics Data System (ADS)

Shirsat, Uddhav; Ahuja, Basant; Dhuttargaon, Mukund

2017-08-01

Burnishing is cold working process in which hard balls are pressed against the surface, resulting in improved surface finish. The surface gets compressed and then plasticized. This is a highly finishing process which is becoming more popular. Surface quality of the product improves its aesthetic appearance. The product made up of aluminum material is subjected to burnishing process during which kerosene is used as a lubricant. In this study factors affecting burnishing process such as burnishing force, speed, feed, work piece diameter and ball diameter are considered as input parameters while surface finish is considered as an output parameter In this study, experiments are designed using 25 factorial design in order to analyze the relationship between input and output parameters. The ANOVA technique and F-test are used for further analysis.

Super-smooth processing x-ray telescope application research based on the magnetorheological finishing (MRF) technology

NASA Astrophysics Data System (ADS)

Zhong, Xianyun; Hou, Xi; Yang, Jinshan

2016-09-01

Nickel is the unique material in the X-ray telescopes. And it has the typical soft material characteristics with low hardness high surface damage and low stability of thermal. The traditional fabrication techniques are exposed to lots of problems, including great surface scratches, high sub-surface damage and poor surface roughness and so on. The current fabrication technology for the nickel aspheric mainly adopt the single point diamond turning(SPDT), which has lots of advantages such as high efficiency, ultra-precision surface figure, low sub-surface damage and so on. But the residual surface texture of SPDT will cause great scattering losses and fall far short from the requirement in the X-ray applications. This paper mainly investigates the magnetorheological finishing (MRF) techniques for the super-smooth processing on the nickel optics. Through the study of the MRF polishing techniques, we obtained the ideal super-smooth polishing technique based on the self-controlled MRF-fluid NS-1, and finished the high-precision surface figure lower than RMS λ/80 (λ=632.8nm) and super-smooth roughness lower than Ra 0.3nm on the plane reflector and roughness lower than Ra 0.4nm on the convex cone. The studying of the MRF techniques makes a great effort to the state-of-the-art nickel material processing level for the X-ray optical systems applications.

Deterministic magnetorheological finishing of optical aspheric mirrors

NASA Astrophysics Data System (ADS)

Song, Ci; Dai, Yifan; Peng, Xiaoqiang; Li, Shengyi; Shi, Feng

2009-05-01

A new method magnetorheological finishing (MRF) used for deterministical finishing of optical aspheric mirrors is applied to overcome some disadvantages including low finishing efficiency, long iterative time and unstable convergence in the process of conventional polishing. Based on the introduction of the basic principle of MRF, the key techniques to implement deterministical MRF are also discussed. To demonstrate it, a 200 mm diameter K9 class concave asphere with a vertex radius of 640mm was figured on MRF polish tool developed by ourselves. Through one process about two hours, the surface accuracy peak-to-valley (PV) is improved from initial 0.216λ to final 0.179λ and root-mean-square (RMS) is improved from 0.027λ to 0.017λ (λ = 0.6328um ). High-precision and high-efficiency convergence of optical aspheric surface error shows that MRF is an advanced optical manufacturing method that owns high convergence ratio of surface figure, high precision of optical surfacing, stabile and controllable finishing process. Therefore, utilizing MRF to finish optical aspheric mirrors determinately is credible and stabile; its advantages can be also used for finishing optical elements on varieties of types such as plane mirrors and spherical mirrors.

Precision machining of optical surfaces with subaperture correction technologies MRF and IBF

NASA Astrophysics Data System (ADS)

Schmelzer, Olaf; Feldkamp, Roman

2015-10-01

Precision optical elements are used in a wide range of technical instrumentations. Many optical systems e.g. semiconductor inspection modules, laser heads for laser material processing or high end movie cameras, contain precision optics even aspherical or freeform surfaces. Critical parameters for such systems are wavefront error, image field curvature or scattered light. Following these demands the lens parameters are also critical concerning power and RMSi of the surface form error and micro roughness. How can we reach these requirements? The emphasis of this discussion is set on the application of subaperture correction technologies in the fabrication of high-end aspheres and free-forms. The presentation focuses on the technology chain necessary for the production of high-precision aspherical optical components and the characterization of the applied subaperture finishing tools MRF (magneto-rheological finishing) and IBF (ion beam figuring). These technologies open up the possibility of improving the performance of optical systems.

Advances in molecular dynamics simulation of ultra-precision machining of hard and brittle materials

NASA Astrophysics Data System (ADS)

Guo, Xiaoguang; Li, Qiang; Liu, Tao; Kang, Renke; Jin, Zhuji; Guo, Dongming

2017-03-01

Hard and brittle materials, such as silicon, SiC, and optical glasses, are widely used in aerospace, military, integrated circuit, and other fields because of their excellent physical and chemical properties. However, these materials display poor machinability because of their hard and brittle properties. Damages such as surface micro-crack and subsurface damage often occur during machining of hard and brittle materials. Ultra-precision machining is widely used in processing hard and brittle materials to obtain nanoscale machining quality. However, the theoretical mechanism underlying this method remains unclear. This paper provides a review of present research on the molecular dynamics simulation of ultra-precision machining of hard and brittle materials. The future trends in this field are also discussed.

Surface characterization protocol for precision aspheric optics

NASA Astrophysics Data System (ADS)

Sarepaka, RamaGopal V.; Sakthibalan, Siva; Doodala, Somaiah; Panwar, Rakesh S.; Kotaria, Rajendra

2017-10-01

In Advanced Optical Instrumentation, Aspherics provide an effective performance alternative. The aspheric fabrication and surface metrology, followed by aspheric design are complementary iterative processes for Precision Aspheric development. As in fabrication, a holistic approach of aspheric surface characterization is adopted to evaluate actual surface error and to aim at the deliverance of aspheric optics with desired surface quality. Precision optical surfaces are characterized by profilometry or by interferometry. Aspheric profiles are characterized by contact profilometers, through linear surface scans to analyze their Form, Figure and Finish errors. One must ensure that, the surface characterization procedure does not add to the resident profile errors (generated during the aspheric surface fabrication). This presentation examines the errors introduced post-surface generation and during profilometry of aspheric profiles. This effort is to identify sources of errors and is to optimize the metrology process. The sources of error during profilometry may be due to: profilometer settings, work-piece placement on the profilometer stage, selection of zenith/nadir points of aspheric profiles, metrology protocols, clear aperture - diameter analysis, computational limitations of the profiler and the software issues etc. At OPTICA, a PGI 1200 FTS contact profilometer (Taylor-Hobson make) is used for this study. Precision Optics of various profiles are studied, with due attention to possible sources of errors during characterization, with multi-directional scan approach for uniformity and repeatability of error estimation. This study provides an insight of aspheric surface characterization and helps in optimal aspheric surface production methodology.

Solder flow over fine line PWB surface finishes

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

Hosking, F.M.; Hernandez, C.L.

1998-08-01

The rapid advancement of interconnect technology has stimulated the development of alternative printed wiring board (PWB) surface finishes to enhance the solderability of standard copper and solder-coated surfaces. These new finishes are based on either metallic or organic chemistries. As part of an ongoing solderability study, Sandia National Laboratories has investigated the solder flow behavior of two azole-based organic solderability preservations, immersion Au, immersion Ag, electroless Pd, and electroless Pd/Ni on fine line copper features. The coated substrates were solder tested in the as-fabricated and environmentally-stressed conditions. Samples were processed through an inerted reflow machine. The azole-based coatings generally providedmore » the most effective protection after aging. Thin Pd over Cu yielded the best wetting results of the metallic coatings, with complete dissolution of the Pd overcoat and wetting of the underlying Cu by the flowing solder. Limited wetting was measured on the thicker Pd and Pd over Ni finishes, which were not completely dissolved by the molten solder. The immersion Au and Ag finishes yielded the lowest wetted lengths, respectively. These general differences in solderability were directly attributed to the type of surface finish which the solder came in contact with. The effects of circuit geometry, surface finish, stressing, and solder processing conditions are discussed.« less

Surface finishing. [for aircraft wings

NASA Technical Reports Server (NTRS)

Kinzler, J. A.; Heffernan, J. T.; Fehrenkamp, L. G.; Lee, W. S. (Inventor)

1977-01-01

A surface of an article adapted for relative motion with a fluid environment is finished by coating the surface with a fluid adhesive. The adhesive is covered with a sheet of flexible film material under tension, and the adhesive is set while maintaining tension on the film material.

Fabrication of a wide-field NIR integral field unit for SWIMS using ultra-precision cutting

NASA Astrophysics Data System (ADS)

Kitagawa, Yutaro; Yamagata, Yutaka; Morita, Shin-ya; Motohara, Kentaro; Ozaki, Shinobu; Takahashi, Hidenori; Konishi, Masahiro; Kato, Natsuko M.; Kobayakawa, Yutaka; Terao, Yasunori; Ohashi, Hirofumi

2016-07-01

We describe overview of fabrication methods and measurement results of test fabrications of optical surfaces for an integral field unit (IFU) for Simultaneous color Wide-field Infrared Multi-object Spectrograph, SWIMS, which is a first-generation instrument for the University of Tokyo Atacama Observatory 6.5-m telescope. SWIMS-IFU provides entire near-infrared spectrum from 0.9 to 2.5 μm simultaneously covering wider field of view of 17" × 13" compared with current near-infrared IFUs. We investigate an ultra-precision cutting technique to monolithically fabricate optical surfaces of IFU optics such as an image slicer. Using 4- or 5-axis ultra precision machine we compare the milling process and shaper cutting process to find the best way of fabrication of image slicers. The measurement results show that the surface roughness almost satisfies our requirement in both of two methods. Moreover, we also obtain ideal surface form in the shaper cutting process. This method will be adopted to other mirror arrays (i.e. pupil mirror and slit mirror, and such monolithic fabrications will also help us to considerably reduce alignment procedure of each optical elements.

SEM Evaluation of Surrounding Enamel after Finishing of Composite Restorations- Preliminary Results

NASA Astrophysics Data System (ADS)

Iovan, G.; Stoleriu, S.; Solomon, S.; Ghiorghe, A.; Sandu, A. V.; Andrian, S.

2017-06-01

The purpose of this study was to analyze the surface characteristics of the enamel adjacent to composite resin after finishing the restoration with different diamond and tungsten carbide burs. The topography of enamel was observed by using a scanning electron microscope. Finishing with extra-/ultra-fine carbide burs, and extra-fine diamond burs resulted in smooth surfaces. In few areas some superficial scratches with no clinical relevance were observed. Deep grooves were observed on the surface of enamel when fine diamond burs were used. Finishing of composite restorations with coarse burs should be avoided when there is a high risk of touching and scratching adjacent enamel during the procedure.

Toward Magnetorheological Finishing of Magnetic Materials

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

Shafrir, S.N.; Lambropoulos, J.C.; Jacobs, S.D.

2007-10-24

Magnetorheological finishing (MRF) is a precision finishing process traditionally limited to processing only nonmagnetic materials, e.g., optical glasses, ceramics, polymers, and metals. Here we demonstrate that MRF can be used for material removal from magnetic material surfaces. Our approach is to place an MRF spot on machined surfaces of magnetic WC-Co materials. The resulting surface roughness is comparable to that produced on nonmagnetic materials. This spotting technique may be used to evaluate the depth of subsurface damage, or deformed layer, induced by earlier manufacturing steps, such as grinding and lapping.

Ductile and brittle transition behavior of titanium alloys in ultra-precision machining.

PubMed

Yip, W S; To, S

2018-03-02

Titanium alloys are extensively applied in biomedical industries due to their excellent material properties. However, they are recognized as difficult to cut materials due to their low thermal conductivity, which induces a complexity to their deformation mechanisms and restricts precise productions. This paper presents a new observation about the removal regime of titanium alloys. The experimental results, including the chip formation, thrust force signal and surface profile, showed that there was a critical cutting distance to achieve better surface integrity of machined surface. The machined areas with better surface roughness were located before the clear transition point, defining as the ductile to brittle transition. The machined area at the brittle region displayed the fracture deformation which showed cracks on the surface edge. The relationship between depth of cut and the ductile to brittle transaction behavior of titanium alloys in ultra-precision machining(UPM) was also revealed in this study, it showed that the ductile to brittle transaction behavior of titanium alloys occurred mainly at relatively small depth of cut. The study firstly defines the ductile to brittle transition behavior of titanium alloys in UPM, contributing the information of ductile machining as an optimal machining condition for precise productions of titanium alloys.

Chemically Accelerated Vibratory Surface Finishing (CAVSF)

DTIC Science & Technology

2009-02-01

media) • End-roughness and micro structure of different C- steels • Material removal and roughness changes versus the amount of treatment solution in...surface finishing (CAVSF) Visual appearance of strip steel test pieces during the CAVSF process. 0-120 minutes = acid treatment 120-135 minutes = water... steel during the super-finishing process 0 50 100 150 200 250 300 350 0 50 100 150 200 250 Time minutes R e m o v e d m a t e r i a l m i c r

Magnetorheological Finishing for Imprinting Continuous Phase Plate Structure onto Optical Surfaces

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

Menapace, J A; Dixit, S N; Genin, F Y

2004-01-05

Magnetorheological finishing (MRF) techniques have been developed to manufacture continuous phase plates (CPP's) and custom phase corrective structures on polished fused silica surfaces. These phase structures are important for laser applications requiring precise manipulation and control of beam-shape, energy distribution, and wavefront profile. The MRF's unique deterministic-sub-aperture polishing characteristics make it possible to imprint complex topographical information onto optical surfaces at spatial scale-lengths approaching 1 mm. In this study, we present the results of experiments and model calculations that explore imprinting two-dimensional sinusoidal structures. Results show how the MRF removal function impacts and limits imprint fidelity and what must bemore » done to arrive at a high quality surface. We also present several examples of this imprinting technology for fabrication of phase correction plates and CPPs for use at high fluences.« less

APPROACHING ZERO DISCHARGE IN SURFACE FINISHING

EPA Science Inventory

This document provides guidance to surface finishing manufacturers on control technologies and process changes for approaching zero discharge (AZD). AZD is a key theme underlying the Strategic Goals Program (SGP). The SGP is a cooperative effort between the EPA nd the American El...

High precision processing CaF2 application research based on the magnetorheological finishing (MRF) technology

NASA Astrophysics Data System (ADS)

Zhong, Xianyun; Fan, Bin; Wu, Fan

2017-10-01

Single crystal calcium fluoride (CaF2) is the excellent transparent optical substance that has extremely good permeability and refractive index from 120nm wavelength ultraviolet range to 12μm wavelength infrared range and it has widely used in the applications of various advanced optical instrument, such as infrared optical systems (IR), short wavelength optical lithography systems (DUV), as well as high power UV laser systems. Nevertheless, the characteristics of CaF2 material, including low fracture toughness, low hardness, low thermal conductivity and high thermal expansion coefficient, result in that the conventional pitch polishing techniques usually expose to lots of problems, such as subsurface damage, scratches, digs and so on. Single point diamond turning (SPDT) is a prospective technology for manufacture the brittle material, but the residual surface textures or artifacts of SPDT will cause great scattering losses. Meanwhile, the roughness also falls far short from the requirement in the short wavelength optical systems. So, the advanced processing technologies for obtaining the shape accuracy, roughness, surface flaw at the same time need to put forward. In this paper, the authors investigate the Magnetorheological Finishing (MRF) technology for the high precision processing of CaF2 material. We finish the surface accuracy RMS λ/150 and roughness Rq 0.3nm on the concave aspheric from originate shape error 0.7λ and roughness 17nm by the SPDT. The studying of the MRF techniques makes a great effort to the processing level of CaF2 material for the state-of-the-art DUV lithography systems applications.

Influence of the initial surface texture on the resulting surface roughness and waviness for micro-machining with ultra-short laser pulses (Conference Presentation)

NASA Astrophysics Data System (ADS)

Remund, Stefan M.; Jaeggi, Beat; Kramer, Thorsten; Neuenschwander, Beat

2017-03-01

The resulting surface roughness and waviness after processing with ultra-short pulsed laser radiation depend on the laser parameters as well as on the machining strategy and the scanning system. However the results depend on the material and its initial surface quality and finishing as well. The improvement of surface finishing represents effort and produces additional costs. For industrial applications it is important to reduce the preparation of a workpiece for laser micro-machining to optimize quality and reduce costs. The effects of the ablation process and the influence of the machining strategy and scanning system onto the surface roughness and waviness can be differenced due to their separate manner. By using the optimal laser parameters on an initially perfect surface, the ablation process mainly increases the roughness to a certain value for most metallic materials. However, imperfections in the scanning system causing a slight variation in the scanning speed lead to a raise of the waviness on the sample surface. For a basic understanding of the influence of grinding marks, the sample surfaces were initially furnished with regular grooves of different depths and spatial frequencies to gain a homogenous and well-defined original surface. On these surfaces the effect of different beam waists and machining strategy are investigated and the results are compared with a simulation of the process. Furthermore the behaviors of common surface finishes used in industrial applications for laser micro-machining are studied and the relation onto the resulting surface roughness and waviness is presented.

Surface Fatigue Lives of Case-Carburized Gears With an Improved Surface Finish

NASA Technical Reports Server (NTRS)

Krantz, T. L.; Alanou, M. P.; Evans, H. P.; Snidle, R. W.; Krantz, T. L. (Technical Monitor)

2000-01-01

Previous research provides qualitative evidence that an improved surface finish can increase the surface fatigue lives of gears. To quantify the influence of surface roughness on life, a set of AISI 93 10 steel gears was provided with a nearmirror finish by superfinishing. The effects of the superfinishing on the quality of the gear tooth surfaces were determined using data from metrology, profilometry, and interferometric microscope inspections. The superfinishing reduced the roughness average by about a factor of 5. The superfinished gears were subjected to surface fatigue testing at 1.71 -GPa (248-ksi) Hertz contact stress, and the data were compared with the NASA Glenn gear fatigue data base. The lives of gears with superfinished teeth were about four times greater compared with the lives of gears with ground teeth but with otherwise similar quality.

Sensor-Based Inspection of the Formation Accuracy in Ultra-Precision Grinding (UPG) of Aspheric Surface Considering the Chatter Vibration

NASA Astrophysics Data System (ADS)

Lei, Yao; Bai, Yue; Xu, Zhijun

2018-06-01

This paper proposes an experimental approach for monitoring and inspection of the formation accuracy in ultra-precision grinding (UPG) with respect to the chatter vibration. Two factors related to the grinding progress, the grinding speed of grinding wheel and spindle, and the oil pressure of the hydrostatic bearing are taken into account to determining the accuracy. In the meantime, a mathematical model of the radius deviation caused by the micro vibration is also established and applied in the experiments. The results show that the accuracy is sensitive to the vibration and the forming accuracy is much improved with proper processing parameters. It is found that the accuracy of aspheric surface can be less than 4 μm when the grinding speed is 1400 r/min and the wheel speed is 100 r/min with the oil pressure being 1.1 MPa.

Precision optical slit for high heat load or ultra high vacuum

DOEpatents

Andresen, Nord C.; DiGennaro, Richard S.; Swain, Thomas L.

1995-01-01

This invention relates generally to slits used in optics that must be precisely aligned and adjusted. The optical slits of the present invention are useful in x-ray optics, x-ray beam lines, optical systems in which the entrance slit is critical for high wavelength resolution. The invention is particularly useful in ultra high vacuum systems where lubricants are difficult to use and designs which avoid the movement of metal parts against one another are important, such as monochrometers for high wavelength resolution with ultra high vacuum systems. The invention further relates to optical systems in which temperature characteristics of the slit materials is important. The present invention yet additionally relates to precision slits wherein the opposing edges of the slit must be precisely moved relative to a center line between the edges with each edge retaining its parallel orientation with respect to the other edge and/or the center line.

Enhancing Surface Finish of Additively Manufactured Titanium and Cobalt Chrome Elements Using Laser Based Finishing

NASA Astrophysics Data System (ADS)

Gora, Wojciech S.; Tian, Yingtao; Cabo, Aldara Pan; Ardron, Marcus; Maier, Robert R. J.; Prangnell, Philip; Weston, Nicholas J.; Hand, Duncan P.

Additive manufacturing (AM) offers the possibility of creating a complex free form object as a single element, which is not possible using traditional mechanical machining. Unfortunately the typically rough surface finish of additively manufactured parts is unsuitable for many applications. As a result AM parts must be post-processed; typically mechanically machined and/or and polished using either chemical or mechanical techniques (both of which have their limitations). Laser based polishing is based on remelting of a very thin surface layer and it offers potential as a highly repeatable, higher speed process capable of selective area polishing, and without any waste problems (no abrasives or liquids). In this paper an in-depth investigation of CW laser polishing of titanium and cobalt chrome AM elements is presented. The impact of different scanning strategies, laser parameters and initial surface condition on the achieved surface finish is evaluated.

Precision optical slit for high heat load or ultra high vacuum

DOEpatents

Andresen, N.C.; DiGennaro, R.S.; Swain, T.L.

1995-01-24

This invention relates generally to slits used in optics that must be precisely aligned and adjusted. The optical slits of the present invention are useful in x-ray optics, x-ray beam lines, optical systems in which the entrance slit is critical for high wavelength resolution. The invention is particularly useful in ultra high vacuum systems where lubricants are difficult to use and designs which avoid the movement of metal parts against one another are important, such as monochromators for high wavelength resolution with ultra high vacuum systems. The invention further relates to optical systems in which temperature characteristics of the slit materials is important. The present invention yet additionally relates to precision slits wherein the opposing edges of the slit must be precisely moved relative to a center line between the edges with each edge retaining its parallel orientation with respect to the other edge and/or the center line. 21 figures.

Research on subsurface deformed layer in ultra-precision cutting of single crystal copper by focused ion beam etching method

NASA Astrophysics Data System (ADS)

Chen, Y.; Huang, X. J.; Kong, J. X.

2018-03-01

In this paper, the focused ion beam was used to study the subsurface deformed layer of single crystal copper caused by the nanoscale single-point diamond fly cutting, and the possibility of using nanometer ultra-precision cutting to remove the larger deformation layer caused by traditional rough cutting process was explored. The maximum cutting thickness of single-point diamond cutting was about 146 nm, and the surface of the single-crystal copper after cutting was etched and observed by using the focused ion beam method. It was found that the morphology of the near-surface layer and the intermediate layer of the copper material were larger differences: the near-surface of the material was smaller and more compact, and the intermediate material layer of the material was more coarse sparse. The results showed that the traditional precision cutting would residual significant subsurface deformed layer and the thickness was on micron level. Even more, the subsurface deformed layer was obviously removed from about 12μm to 5μm after single-point diamond fly cutting in this paper. This paper proved that the large-scale subsurface deformed layer caused by traditional cutting process could be removed by nanometer ultra-precision cutting. It was of great significance to further establish the method that control of the deformation of weak rigid components by reducing the depth of the subsurface deformed layers.

Effect of Blade-surface Finish on Performance of a Single-stage Axial-flow Compressor

NASA Technical Reports Server (NTRS)

Moses, Jason J; Serovy, George, K

1951-01-01

A set of modified NACA 5509-34 rotor and stator blades was investigated with rough-machine, hand-filed, and highly polished surface finishes over a range of weight flows at six equivalent tip speeds from 672 to 1092 feet per second to determine the effect of blade-surface finish on the performance of a single-stage axial-flow compressor. Surface-finish effects decreased with increasing compressor speed and with decreasing flow at a given speed. In general, finishing blade surfaces below the roughness that may be considered aerodynamically smooth on the basis of an admissible-roughness formula will have no effect on compressor performance.

Surface texture of resin-modified glass ionomer cements: effects of finishing/polishing time.

PubMed

Yap, A U J; Ong, S B; Yap, W Y; Tan, W S; Yeo, J C

2002-01-01

This study compared the surface texture of resin-modified glass ionomer cements after immediate and delayed finishing with different finishing/polishing systems. Class V preparations were made on the buccal and lingual/palatal surfaces of 64 freshly extracted teeth. The cavities on each tooth were restored with Fuji II LC (GC) and Photac-Fil Quick (3M-ESPE) according to manufacturers' instructions. Immediately after light-polymerization, gross finishing was done with 8-fluted tungsten carbide burs. The teeth were then randomly divided into four groups of 16 teeth. Half of the teeth in each group were finished immediately, while the remaining half were finished after one-week storage in distilled water at 37 degrees C. The following finishing/polishing systems were employed: (a) Robot Carbides; (b) Super-Snap system; (c) OneGloss and (d) CompoSite Polishers. The mean surface roughness (microm; n=8) in vertical (RaV) and horizontal (RaH) axis was measured using a profilometer. Data was subjected to ANOVA/Scheffe's tests and Independent Samples t-test at significance level 0.05. Ra values were generally lower in both vertical and horizontal axis with delayed finishing/polishing. Although significant differences in RaV and RaH values were observed among several systems with immediate finishing/polishing, only one (Fuji II LC: RaH - Super-Snap < Robot Carbides) was observed with delayed finishing.

Computer Simulation Of An In-Process Surface Finish Sensor.

NASA Astrophysics Data System (ADS)

Rakels, Jan H.

1987-01-01

It is generally accepted, that optical methods are the most promising for the in-process measurement of surface finish. These methods have the advantages of being non-contacting and fast data acquisition. Furthermore, these optical instruments can be easily retrofitted on existing machine-tools. In the Micro-Engineering Centre at the University of Warwick, an optical sensor has been developed which can measure the rms roughness, slope and wavelength of turned and precision ground surfaces during machining. The operation of this device is based upon the Kirchhoff-Fresnel diffraction integral. Application of this theory to ideal turned and ground surfaces is straightforward, and indeed the calculated diffraction patterns are in close agreement with patterns produced by an actual optical instrument. Since it is mathematically difficult to introduce real machine-tool behaviour into the diffraction integral, a computer program has been devised, which simulates the operation of the optical sensor. The program produces a diffraction pattern as a graphical output. Comparison between computer generated and actual diffraction patterns of the same surfaces show a high correlation. The main aim of this program is to construct an atlas, which maps known machine-tool errors versus optical diffraction patterns. This atlas can then be used for machine-tool condition diagnostics. It has been found that optical monitoring is very sensitive to minor defects. Therefore machine-tool detoriation can be detected before it is detrimental.

Implementing Cleaner Printed Wiring Board Technologies: Surface Finishes

EPA Pesticide Factsheets

This document describes the problems, solutions, and time and effort involved in implementing alternative surface finish technologies, and this guide is produced as part of the DfE Printed Wiring Board Project

Effects of delayed finishing/polishing on surface roughness, hardness and gloss of tooth-coloured restorative materials.

PubMed

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

2010-01-01

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. 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 <.05). The smoothest surfaces were obtained under Mylar strip for all materials. While there were no significant differences in surface roughness of immediate and delayed finished/polished Dyract Extra samples, immediately finished/polished Venus and Grandio samples showed significantly higher roughness than the delayed polished samples (P <.05). In Tetric Flow samples, immediately finishing/polishing provided smoother surface than delayed finishing/polishing (P <.05). The highest gloss values were recorded under Mylar strip for all materials. While delayed finishing/polishing resulted in a significantly higher gloss compared to immediate finishing/polishing in Venus samples (P <.05), no differences were observed between delayed or immediate finishing/polishing for the other materials (P>.05). The lowest hardness values were found under Mylar strip. Delayed finishing/polishing significantly increased the hardness of all materials. The

Surface Finish and Residual Stresses Induced by Orthogonal Dry Machining of AA7075-T651

PubMed Central

Jomaa, Walid; Songmene, Victor; Bocher, Philippe

2014-01-01

The surface finish was extensively studied in usual machining processes (turning, milling, and drilling). For these processes, the surface finish is strongly influenced by the cutting feed and the tool nose radius. However, a basic understanding of tool/surface finish interaction and residual stress generation has been lacking. This paper aims to investigate the surface finish and residual stresses under the orthogonal cutting since it can provide this information by avoiding the effect of the tool nose radius. The orthogonal machining of AA7075-T651 alloy through a series of cutting experiments was performed under dry conditions. Surface finish was studied using height and amplitude distribution roughness parameters. SEM and EDS were used to analyze surface damage and built-up edge (BUE) formation. An analysis of the surface topography showed that the surface roughness was sensitive to changes in cutting parameters. It was found that the formation of BUE and the interaction between the tool edge and the iron-rich intermetallic particles play a determinant role in controlling the surface finish during dry orthogonal machining of the AA7075-T651 alloy. Hoop stress was predominantly compressive on the surface and tended to be tensile with increased cutting speed. The reverse occurred for the surface axial stress. The smaller the cutting feed, the greater is the effect of cutting speed on both axial and hoop stresses. By controlling the cutting speed and feed, it is possible to generate a benchmark residual stress state and good surface finish using dry machining. PMID:28788534

Analyzing and improving surface texture by dual-rotation magnetorheological finishing

NASA Astrophysics Data System (ADS)

Wang, Yuyue; Zhang, Yun; Feng, Zhijing

2016-01-01

The main advantages of magnetorheological finishing (MRF) are its high convergence rate of surface error, the ability of polishing aspheric surfaces and nearly no subsurface damage. However, common MRF produces directional surface texture due to the constant flow direction of the magnetorheological (MR) polishing fluid. This paper studies the mechanism of surface texture formation by texture modeling. Dual-rotation magnetorheological finishing (DRMRF) is presented to suppress directional surface texture after analyzing the results of the texture model for common MRF. The results of the surface texture model for DRMRF and the proposed quantitative method based on mathematical statistics indicate the effective suppression of directional surface texture. An experimental setup is developed and experiments show directional surface texture and no directional surface texture in common MRF and DRMRF, respectively. As a result, the surface roughness of DRMRF is 0.578 nm (root-mean-square value) which is lower than 1.109 nm in common MRF.

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

PubMed

Madhyastha, Prashanthi Sampath; Hegde, Shreya; Srikant, N; Kotian, Ravindra; Iyer, Srividhya Sriraman

2017-01-01

Surface roughness associated with improper finishing/polishing of restorations can result in plaque accumulation, gingival irritation, surface staining, and poor esthetic of restored teeth. The study aimed to evaluate the efficiency of various finishing and polishing systems and time using various procedures on surface roughness of some esthetic restorative materials. In this in vitro study, samples of two composite materials, compomer and glass ionomer cement (GIC) materials, were fabricated. Finishing and polishing were done immediately ( n = 40) and after 1 week ( n = 40) using four systems (diamond bur + soflex discs; diamond bur + Astropol polishing brush; tungsten carbide bur + soflex discs; tungsten carbide bur + Astropol polishing brush). Surface roughness was measured using surface profilometer. Data were statistically analyzed by t -test (for each material and time period) and one-way analysis of variance followed by Tukey's post hoc (for finishing and polishing systems) at a significant level of P < 0.05. Analysis of time period, irrespective of finishing and polishing system showed that Ra values were greater ( P < 0.05) in delayed polishing in GIC > Z100 > Filtek P90 > Dyract AP, suggesting immediate polishing is better. Among the materials, Filtek P90 had the least Ra values indicating the smoothest surface among all materials, followed by Z100, Dyract AP, and GIC. Comparison of polishing and finishing systems irrespective of materials showed that Ra values were lower ( P > 0.05) in diamond + Astropol combination whereas diamond + soflex had the greatest Ra values. 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.

Surface Finish Effects Using Coating Method on 3D Printing (FDM) Parts

NASA Astrophysics Data System (ADS)

Haidiezul, AHM; Aiman, AF; Bakar, B.

2018-03-01

One of three-dimensional (3-D) printing economical processes is by using Fused Deposition Modelling (FDM). The 3-D printed object was built using layer-by-layer approach which caused “stair stepping” effects. This situation leads to uneven surface finish which mostly affect the objects appearance for product designers in presenting their models or prototypes. The objective of this paper is to examine the surface finish effects from the application of XTC-3D coating developed by Smooth-On, USA on the 3D printed parts. From the experimental works, this study shows the application of XTC-3D coating to the 3-D printed parts has improve the surface finish by reducing the gap between the layer

Portable flooring protects finished surfaces, is easily moved

NASA Technical Reports Server (NTRS)

Carmody, R. J.

1964-01-01

To protect curved, finished surface and provide support for workmen, portable flooring has been made from rigid plastic foam blocks, faced with aluminum strips. Held together by nylon webbing, the flooring can be rolled up for easy carrying.

An ultra-precision tool nanoindentation instrument for replication of single point diamond tool cutting edges

NASA Astrophysics Data System (ADS)

Cai, Yindi; Chen, Yuan-Liu; Xu, Malu; Shimizu, Yuki; Ito, So; Matsukuma, Hiraku; Gao, Wei

2018-05-01

Precision replication of the diamond tool cutting edge is required for non-destructive tool metrology. This paper presents an ultra-precision tool nanoindentation instrument designed and constructed for replication of the cutting edge of a single point diamond tool onto a selected soft metal workpiece by precisely indenting the tool cutting edge into the workpiece surface. The instrument has the ability to control the indentation depth with a nanometric resolution, enabling the replication of tool cutting edges with high precision. The motion of the diamond tool along the indentation direction is controlled by the piezoelectric actuator of a fast tool servo (FTS). An integrated capacitive sensor of the FTS is employed to detect the displacement of the diamond tool. The soft metal workpiece is attached to an aluminum cantilever whose deflection is monitored by another capacitive sensor, referred to as an outside capacitive sensor. The indentation force and depth can be accurately evaluated from the diamond tool displacement, the cantilever deflection and the cantilever spring constant. Experiments were carried out by replicating the cutting edge of a single point diamond tool with a nose radius of 2.0 mm on a copper workpiece surface. The profile of the replicated tool cutting edge was measured using an atomic force microscope (AFM). The effectiveness of the instrument in precision replication of diamond tool cutting edges is well-verified by the experimental results.

Developing magnetorheological finishing (MRF) technology for the manufacture of large-aperture optics in megajoule class laser systems

NASA Astrophysics Data System (ADS)

Menapace, Joseph A.

2010-11-01

Over the last eight years we have been developing advanced MRF tools and techniques to manufacture meter-scale optics for use in Megajoule class laser systems. These systems call for optics having unique characteristics that can complicate their fabrication using conventional polishing methods. First, exposure to the high-power nanosecond and sub-nanosecond pulsed laser environment in the infrared (>27 J/cm2 at 1053 nm), visible (>18 J/cm2 at 527 nm), and ultraviolet (>10 J/cm2 at 351 nm) demands ultra-precise control of optical figure and finish to avoid intensity modulation and scatter that can result in damage to the optics chain or system hardware. Second, the optics must be super-polished and virtually free of surface and subsurface flaws that can limit optic lifetime through laser-induced damage initiation and growth at the flaw sites, particularly at 351 nm. Lastly, ultra-precise optics for beam conditioning are required to control laser beam quality. These optics contain customized surface topographical structures that cannot be made using traditional fabrication processes. In this review, we will present the development and implementation of large-aperture MRF tools and techniques specifically designed to meet the demanding optical performance challenges required in large aperture high-power laser systems. In particular, we will discuss the advances made by using MRF technology to expose and remove surface and subsurface flaws in optics during final polishing to yield optics with improve laser damage resistance, the novel application of MRF deterministic polishing to imprint complex topographical information and wavefront correction patterns onto optical surfaces, and our efforts to advance the technology to manufacture largeaperture damage resistant optics.

Imprinting continuously varying topographical structure onto large-aperture optical surfaces using magnetorheological finishing

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

Menapace, J A; Davis, P J; Dixit, S

2007-03-07

Over the past four years we have advanced Magnetorheological Finishing (MRF) techniques and tools to imprint complex continuously varying topographical structures onto large-aperture (430 x 430 mm) optical surfaces. These optics, known as continuous phase plates (CPPs), are important for high-power laser applications requiring precise manipulation and control of beam-shape, energy distribution, and wavefront profile. MRF's unique deterministic-sub-aperture polishing characteristics make it possible to imprint complex topographical information onto optical surfaces at spatial scale-lengths approaching 1 mm and surface peak-to-valleys as high as 22 {micro}m. During this discussion, we will present the evolution of the MRF imprinting technology and themore » MRF tools designed to manufacture large-aperture 430 x 430 mm CPPs. Our results will show how the MRF removal function impacts and limits imprint fidelity and what must be done to arrive at a high-quality surface. We also present several examples of this imprinting technology for fabrication of phase correction plates and CPPs for use in high-power laser applications.« less

The ultrahigh precision form measurement of small, steep-sided aspheric moulds, incorporating novel hardware and software developments; Technical Digest

NASA Astrophysics Data System (ADS)

Mills, M. W.; Hutchinson, Matthew J.

2005-05-01

A variety of consumer applications, eg cellphone camera lenses, optical storage devices, digital cameras, etc, are driving the demand for small, high aspheric departure rotationally-symmetric moulded optics, manufactured both in polymer and glass materials. The mould tools for such components are manufactured by ultra-high precision techniques such as single point diamond turning and ultra-precision grinding, and must be accurate to <1/10μm levels for form, and exhibit nanometric surface finish quality. The aspheric forms of such components' optical surfaces exhibit high departure from best-fit sphere towards their outer edge, which renders this outer region especially critical for optical performance. The high slope of these components at the clear aperture has caused some restrictions on the use of profilometry in the measurement of form across their full diameter. Taylor Hobson designs and manufactures a range of ultra-precision profilometers for use in such industries as aspheric optics fabrication. In order to address the issues described, a new measurement system, Taylor Hobson Form Talysurf PGI 1250, has been developed, which contains new Aspheric Data Fusion Software, as well as Asphero-Diffractive Analysis Software, allowing the entire diametric profile to be analysed to the desired level of accuracy. This development removes the previous limitation of maximum slope for this type of measurement, thus enabling better quality control of high slope, high aspheric departure optics. Measurement data from the Form Talysurf PGI 1250 can be fed back directly to the machine tool, in order to optimize the form of the optical mould.

The ultrahigh precision form measurement of small, steep-sided aspheric moulds, incorporating novel hardware and software developments; Technical Digest

NASA Astrophysics Data System (ADS)

Mills, M. W.; Hutchinson, Matthew J.

2005-05-01

A variety of consumer applications, eg cellphone camera lenses, optical storage devices, digital cameras, etc, are driving the demand for small, high aspheric departure rotationally-symmetric moulded optics, manufactured both in polymer and glass materials. The mould tools for such components are manufactured by ultra-high precision techniques such as single point diamond turning and ultra-precision grinding, and must be accurate to <1/10μm levels for form, and exhibit nanometric surface finish quality. The aspheric forms of such components" optical surfaces exhibit high departure from best-fit sphere towards their outer edge, which renders this outer region especially critical for optical performance. The high slope of these components at the clear aperture has caused some restrictions on the use of profilometry in the measurement of form across their full diameter. Taylor Hobson designs and manufactures a range of ultra-precision profilometers for use in such industries as aspheric optics fabrication. In order to address the issues described, a new measurement system, Taylor Hobson Form Talysurf PGI 1250, has been developed, which contains new Aspheric Data Fusion Software, as well as Asphero-Diffractive Analysis Software, allowing the entire diametric profile to be analysed to the desired level of accuracy. This development removes the previous limitation of maximum slope for this type of measurement, thus enabling better quality control of high slope, high aspheric departure optics. Measurement data from the Form Talysurf PGI 1250 can be fed back directly to the machine tool, in order to optimize the form of the optical mould.

30 CFR 18.33 - Finish of surface joints.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Finish of surface joints. 18.33 Section 18.33 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and Design...

Novel MRF fluid for ultra-low roughness optical surfaces

NASA Astrophysics Data System (ADS)

Dumas, Paul; McFee, Charles

2014-08-01

Over the past few years there have been an increasing number of applications calling for ultra-low roughness (ULR) surfaces. A critical demand has been driven by EUV optics, EUV photomasks, X-Ray, and high energy laser applications. Achieving ULR results on complex shapes like aspheres and X-Ray mirrors is extremely challenging with conventional polishing techniques. To achieve both tight figure and roughness specifications, substrates typically undergo iterative global and local polishing processes. Typically the local polishing process corrects the figure or flatness but cannot achieve the required surface roughness, whereas the global polishing process produces the required roughness but degrades the figure. Magnetorheological Finishing (MRF) is a local polishing technique based on a magnetically-sensitive fluid that removes material through a shearing mechanism with minimal normal load, thus removing sub-surface damage. The lowest surface roughness produced by current MRF is close to 3 Å RMS. A new ULR MR fluid uses a nano-based cerium as the abrasive in a proprietary aqueous solution, the combination of which reliably produces under 1.5Å RMS roughness on Fused Silica as measured by atomic force microscopy. In addition to the highly convergent figure correction achieved with MRF, we show results of our novel MR fluid achieving <1.5Å RMS roughness on fused silica and other materials.

Effect of Plasma Surface Finish on Wettability and Mechanical Properties of SAC305 Solder Joints

NASA Astrophysics Data System (ADS)

Kim, Kyoung-Ho; Koike, Junichi; Yoon, Jeong-Won; Yoo, Sehoon

2016-12-01

The wetting behavior, interfacial reactions, and mechanical reliability of Sn-Ag-Cu solder on a plasma-coated printed circuit board (PCB) substrate were evaluated under multiple heat-treatments. Conventional organic solderability preservative (OSP) finished PCBs were used as a reference. The plasma process created a dense and highly cross-linked polymer coating on the Cu substrates. The plasma finished samples had higher wetting forces and shorter zero-cross times than those with OSP surface finish. The OSP sample was degraded after sequential multiple heat treatments and reflow processes, whereas the solderability of the plasma finished sample was retained after multiple heat treatments. After the soldering process, similar microstructures were observed at the interfaces of the two solder joints, where the development of intermetallic compounds was observed. From ball shear tests, it was found that the shear force for the plasma substrate was consistently higher than that for the OSP substrate. Deterioration of the OSP surface finish was observed after multiple heat treatments. Overall, the plasma surface finish was superior to the conventional OSP finish with respect to wettability and joint reliability, indicating that it is a suitable material for the fabrication of complex electronic devices.

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

PubMed Central

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 (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. PMID:29104597

Precision lens molding of asphero diffractive surfaces in chalcogenide materials

NASA Astrophysics Data System (ADS)

Nelson, J.; Scordato, M.; Schwertz, K.; Bagwell, J.

2015-10-01

Finished lens molding, and the similar process of precision lens molding, have long been practiced for high volume, accurate replication of optical surfaces on oxide glass. The physics surrounding these processes are well understood, and the processes are capable of producing high quality optics with great fidelity. However, several limitations exist due to properties inherent with oxide glasses. Tooling materials that can withstand the severe environmental conditions of oxide glass molding cannot easily be machined to produce complex geometries such as diffractive surfaces, lens arrays, and off axis features. Current machining technologies coupled with a limited selection of tool materials greatly limits the type of structures that can be molded into the finished optic. Tooling for chalcogenide glasses are not bound by these restrictions since the molding temperatures required are much lower than for oxide glasses. Innovations in tooling materials and manufacturing techniques have enabled the production of complex geometries to optical quality specifications and have demonstrated the viability of creating tools for molding diffractive surfaces, off axis features, datums, and arrays. Applications for optics having these features are found in automotive, defense, security, medical, and industrial domains. This paper will discuss results achieved in the study of various molding techniques for the formation of positive diffractive features on a concave spherical surface molded from As2Se3 chalcogenide glass. Examples and results of molding with tools having CTE match with the glass and non CTE match will be reviewed. The formation of stress within the glass during molding will be discussed, and methods of stress management will also be demonstrated and discussed. Results of process development methods and production of good diffractive surfaces will be shown.

Developing Magnetorheological Finishing (MRF) Technology for the Manufacture of Large-Aperture Optics in Megajoule Class Laser Systems

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

Menapace, J A

2010-10-27

Over the last eight years we have been developing advanced MRF tools and techniques to manufacture meter-scale optics for use in Megajoule class laser systems. These systems call for optics having unique characteristics that can complicate their fabrication using conventional polishing methods. First, exposure to the high-power nanosecond and sub-nanosecond pulsed laser environment in the infrared (>27 J/cm{sup 2} at 1053 nm), visible (>18 J/cm{sup 2} at 527 nm), and ultraviolet (>10 J/cm{sup 2} at 351 nm) demands ultra-precise control of optical figure and finish to avoid intensity modulation and scatter that can result in damage to the optics chainmore » or system hardware. Second, the optics must be super-polished and virtually free of surface and subsurface flaws that can limit optic lifetime through laser-induced damage initiation and growth at the flaw sites, particularly at 351 nm. Lastly, ultra-precise optics for beam conditioning are required to control laser beam quality. These optics contain customized surface topographical structures that cannot be made using traditional fabrication processes. In this review, we will present the development and implementation of large-aperture MRF tools and techniques specifically designed to meet the demanding optical performance challenges required in large-aperture high-power laser systems. In particular, we will discuss the advances made by using MRF technology to expose and remove surface and subsurface flaws in optics during final polishing to yield optics with improve laser damage resistance, the novel application of MRF deterministic polishing to imprint complex topographical information and wavefront correction patterns onto optical surfaces, and our efforts to advance the technology to manufacture large-aperture damage resistant optics.« less

Relationship between influence function accuracy and polishing quality in magnetorheological finishing

NASA Astrophysics Data System (ADS)

Schinhaerl, Markus; Schneider, Florian; Rascher, Rolf; Vogt, Christian; Sperber, Peter

2010-10-01

Magnetorheological finishing is a typical commercial application of a computer-controlled polishing process in the manufacturing of precision optical surfaces. Precise knowledge of the material removal characteristic of the polishing tool (influence function) is essential for controlling the material removal on the workpiece surface by the dwell time method. Results from the testing series with magnetorheological finishing have shown that a deviation of only 5% between the actual material removal characteristic of the polishing tool and that represented by the influence function caused a considerable reduction in the polishing quality. The paper discusses reasons for inaccuracies in the influence function and the effects on the polishing quality. The generic results of this research serve for the development of improved polishing strategies, and may be used in alternative applications of computer-controlled polishing processes that quantify the material removal characteristic by influence functions.

Ultra-low roughness magneto-rheological finishing for EUV mask substrates

NASA Astrophysics Data System (ADS)

Dumas, Paul; Jenkins, Richard; McFee, Chuck; Kadaksham, Arun J.; Balachandran, Dave K.; Teki, Ranganath

2013-09-01

EUV mask substrates, made of titania-doped fused silica, ideally require sub-Angstrom surface roughness, sub-30 nm flatness, and no bumps/pits larger than 1 nm in height/depth. To achieve the above specifications, substrates must undergo iterative global and local polishing processes. Magnetorheological finishing (MRF) is a local polishing technique which can accurately and deterministically correct substrate figure, but typically results in a higher surface roughness than the current requirements for EUV substrates. We describe a new super-fine MRF® polishing fluid whichis able to meet both flatness and roughness specifications for EUV mask blanks. This eases the burden on the subsequent global polishing process by decreasing the polishing time, and hence the defectivity and extent of figure distortion.

Ultra-narrow pulse generator with precision-adjustable pulse width

NASA Astrophysics Data System (ADS)

Fu, Zaiming; Liu, Hanglin

2018-05-01

In this paper, a novel ultra-narrow pulse generation approach is proposed. It is based on the decomposition and synthesis of pulse edges. Through controlling their relative delay, an ultra-narrow pulse could be generated. By employing field programmable gate array digital synthesis technology, the implemented pulse generator is with programmable ability. The amplitude of pulse signals is controlled by the radio frequency amplifiers and bias tees, and high precision can be achieved. More importantly, the proposed approach can break through the limitation of device's propagation delay and optimize the resolution and the accuracy of the pulse width significantly. The implemented pulse generator has two channels, whose minimum pulse width, frequency range, and amplitude range are 100 ps, 15 MHz-1.5 GHz, and 0.1 Vpp-1.8 Vpp, respectively. Both resolution of pulse width and channel delay are 1 ps, and amplitude resolution is 10 mVpp.

Quantum preservation of the measurements precision using ultra-short strong pulses in exact analytical solution

NASA Astrophysics Data System (ADS)

Berrada, K.; Eleuch, H.

2017-09-01

Various schemes have been proposed to improve the parameter-estimation precision. In the present work, we suggest an alternative method to preserve the estimation precision by considering a model that closely describes a realistic experimental scenario. We explore this active way to control and enhance the measurements precision for a two-level quantum system interacting with classical electromagnetic field using ultra-short strong pulses with an exact analytical solution, i.e. beyond the rotating wave approximation. In particular, we investigate the variation of the precision with a few cycles pulse and a smooth phase jump over a finite time interval. We show that by acting on the shape of the phase transient and other parameters of the considered system, the amount of information may be increased and has smaller decay rate in the long time. These features make two-level systems incorporated in ultra-short, of-resonant and gradually changing phase good candidates for implementation of schemes for the quantum computation and the coherent information processing.

The influence of surface finishing methods on touch-sensitive reactions

NASA Astrophysics Data System (ADS)

Kukhta, M. S.; Sokolov, A. P.; Krauinsh, P. Y.; Kozlova, A. D.; Bouchard, C.

2017-02-01

This paper describes the modern technological development trends in jewelry design. In the jewelry industry, new trends, associated with the introduction of updated non-traditional materials and finishing techniques, are appearing. The existing information-oriented society enhances the visual aesthetics of new jewelry forms, decoration techniques (depth and surface), synthesis of different materials, which, all in all, reveal a bias towards positive effects of visual design. Today, the jewelry industry includes not only traditional techniques, but also such improved techniques as computer-assisted design, 3D-prototyping and other alternatives to produce an updated level of jewelry material processing. The authors present the specific features of ornamental pattern designing, decoration types (depth and surface) and comparative analysis of different approaches in surface finishing. Identifying the appearance or the effect of jewelry is based on proposed evaluation criteria, providing an advanced visual aesthetics basis is predicated on touch-sensitive responses.

Wear analysis and finishing of bioceramic implant surfaces.

PubMed

Denkena, Berend; Reichstein, Martin; van der Meer, Marijke; Ostermeier, Sven; Hurschler, Christof

2008-01-01

A primary cause for revision operations of joint replacements is the implant loosening, due to immune reactions resulting from the agglomeration of polyethylene wear debris. Motivated by the successful application of bioceramic materials in hip joint prostheses, a trend towards the development of hard implant materials has occurred. Nonetheless in the area of total knee arthroplasty (TKA), modern efforts have still utilized polyethylene as the tibial-inlay joint component. The use of bioceramic hard-hard-pairings for total knee arthroplasty has been prevented by the complex kinematics and geometries required. Ceramics cannot cope with non-uniform loads, which suggests the need for new designs appropriate to the material. Furthermore, biomechanical requirements should be considered. A rolling-gliding wear simulator, which reproduces the movements and stresses of the knee joint on specimens of simplified geometry, has therefore been developed. High-precision machining processes for free formed bioceramic surfaces, with suitable grinding and polishing tools which adjust to constantly changing contact conditions, are essential. The goal is to put automated finishing in one clamping with five simultaneous controlled axes into practice. The developed manufacturing technologies will allow the advantageous bioceramic materials to be applied and accepted for more complex joint replacements such as knee prostheses.

Effects of surface-finishing protocols on the roughness, color change, and translucency of different ceramic systems.

PubMed

Akar, Gülcan Coşkun; Pekkan, Gürel; Çal, Ebru; Eskitaşçıoğlu, Gürcan; Özcan, Mutlu

2014-08-01

Surface-finishing protocols have a mechanical impact on ceramic surfaces that could eventually affect surface topography and light scattering. An optimum protocol is needed to avoid damaging the optical properties of ceramics. The purpose of this study was to determine the effects of different surface-finishing protocols on the surface roughness, color change, and translucency of ceramic and metal ceramic restorations. Standardized disk-shaped specimens (1.5 × 10 mm, n=128) were fabricated from 3 different ceramic core materials (aluminum oxide [Al2O3]-AL, zirconium oxide [ZrO2]-ZR, lithium disilicate [Li2Si2O5]-LIT), veneered (V) with dentin ceramics (n=32 per group), and placed in the following groups: ALV, ZRV, and LITV. The metal ceramic group acted as the control (n=32). Four different surface-finishing methods were tested. Airborne-particle abrasion with 50 μm Al2O3, polishing with adjustment kit, polishing with adjustment kit plus diamond polishing paste, and autoglazing (n=8 subgroup) were applied on the veneering ceramics. The specimens were analyzed with a profilometer for surface roughness, and color change and translucency were measured with a clinical spectrophotometer. Statistical analyses were performed with 1-way ANOVA and the Tukey honest significant difference tests (α=.05). Specimens treated with the airborne particle abrasion method showed significantly higher mean profilometer for surface roughness values in all groups (P<.05). The polishing with adjustment kit and autoglazing methods revealed statistically similar surface roughness values in all groups (P>.05). With the diamond polishing paste method, lower surface roughness values were achieved in the ZRV and metal ceramic groups acted as the control groups. Different surface-finishing methods affected the color change of the ceramic systems, except for ZRV. Surface-finishing protocols significantly affected the translucency values of the ALV, LITV, and metal ceramic groups (P<.05). No

An ultra-stable voltage source for precision Penning-trap experiments

NASA Astrophysics Data System (ADS)

Böhm, Ch.; Sturm, S.; Rischka, A.; Dörr, A.; Eliseev, S.; Goncharov, M.; Höcker, M.; Ketter, J.; Köhler, F.; Marschall, D.; Martin, J.; Obieglo, D.; Repp, J.; Roux, C.; Schüssler, R. X.; Steigleder, M.; Streubel, S.; Wagner, Th.; Westermann, J.; Wieder, V.; Zirpel, R.; Melcher, J.; Blaum, K.

2016-08-01

An ultra-stable and low-noise 25-channel voltage source providing 0 to -100 V has been developed. It will supply stable bias potentials for Penning-trap electrodes used in high-precision experiments. The voltage source generates all its supply voltages via a specially designed transformer. Each channel can be operated either in a precision mode or can be dynamically ramped. A reference module provides reference voltages for all the channels, each of which includes a low-noise amplifier to gain a factor of 10 in the output stage. A relative voltage stability of δV / V ≈ 2 ×10-8 has been demonstrated at -89 V within about 10 min.

Finishing of wood

Treesearch

R. Sam Williams

1999-01-01

The primary function of any wood finish (paint, varnish, and stain, for example) is to protect the wood surface, help maintain a certain appearance, and provide a cleanable surface. Although wood can be used both outdoors and indoors without finishing, unfinished wood surfaces exposed to the weather change color, are roughened by photodegradation and surface checking,...

Choice of crystal surface finishing for a dual-ended readout depth-of-interaction (DOI) detector.

PubMed

Fan, Peng; Ma, Tianyu; Wei, Qingyang; Yao, Rutao; Liu, Yaqiang; Wang, Shi

2016-02-07

The objective of this study was to choose the crystal surface finishing for a dual-ended readout (DER) DOI detector. Through Monte Carlo simulations and experimental studies, we evaluated 4 crystal surface finishing options as combinations of crystal surface polishing (diffuse or specular) and reflector (diffuse or specular) options on a DER detector. We also tested one linear and one logarithm DOI calculation algorithm. The figures of merit used were DOI resolution, DOI positioning error, and energy resolution. Both the simulation and experimental results show that (1) choosing a diffuse type in either surface polishing or reflector would improve DOI resolution but degrade energy resolution; (2) crystal surface finishing with a diffuse polishing combined with a specular reflector appears a favorable candidate with a good balance of DOI and energy resolution; and (3) the linear and logarithm DOI calculation algorithms show overall comparable DOI error, and the linear algorithm was better for photon interactions near the ends of the crystal while the logarithm algorithm was better near the center. These results provide useful guidance in DER DOI detector design in choosing the crystal surface finishing and DOI calculation methods.

Lathe Attachment Finishes Inner Surface of Tubes

NASA Technical Reports Server (NTRS)

Lancki, A. J.

1982-01-01

Extremely smooth finishes are machined on inside surfaces of tubes by new attachment for a lathe. The relatively inexpensive accessory, called a "microhone," holds a honing stone against workpiece by rigid tangs instead of springs as in conventional honing tools. Inner rod permits adjustment of microhoning stone, while outer tube supports assembly. Outer tube is held between split blocks on lathe toolpost. Microhoning can be done with either microhone or workpiece moving and other member stationary.

Rheological properties of magnetorheological fluid and its finishing application on large aperture BK7 glass

NASA Astrophysics Data System (ADS)

Wang, C.; Wei, Q. L.; Huang, W.; Luo, Q.; He, J. G.; Tang, G. P.

2013-07-01

The CeO2 nanoparticles with modified surface and mean sizes distribution during 107.0 nm - 127.7 nm are used as abrasive in magnetorheological finishing (MRF) fluid. The slow rotation dispersion without shearing thinning is better than fast emulsification dispersion. Steady D-shaped finishing spots and high quality precise processing surface with PV=0.1λ, GRMS=0.002λ/cm, Rq=0.83 nm are obtained on a 435 mm x 435 mm BK7 glass under self-developed MRF apparatus.

Ultra-precision positioning assembly

DOEpatents

Montesanti, Richard C.; Locke, Stanley F.; Thompson, Samuel L.

2002-01-01

An apparatus and method is disclosed for ultra-precision positioning. A slide base provides a foundational support. A slide plate moves with respect to the slide base along a first geometric axis. Either a ball-screw or a piezoelectric actuator working separate or in conjunction displaces the slide plate with respect to the slide base along the first geometric axis. A linking device directs a primary force vector into a center-line of the ball-screw. The linking device consists of a first link which directs a first portion of the primary force vector to an apex point, located along the center-line of the ball-screw, and a second link for directing a second portion of the primary force vector to the apex point. A set of rails, oriented substantially parallel to the center-line of the ball-screw, direct movement of the slide plate with respect to the slide base along the first geometric axis and are positioned such that the apex point falls within a geometric plane formed by the rails. The slide base, the slide plate, the ball-screw, and the linking device together form a slide assembly. Multiple slide assemblies can be distributed about a platform. In such a configuration, the platform may be raised and lowered, or tipped and tilted by jointly or independently displacing the slide plates.

77 FR 12227 - Long Term 2 Enhanced Surface Water Treatment Rule: Uncovered Finished Water Reservoirs; Public...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-29

... Water Treatment Rule: Uncovered Finished Water Reservoirs; Public Meeting AGENCY: Environmental... review of the uncovered finished water reservoir requirement in the Long Term 2 Enhanced Surface Water... uncovered finished water reservoir requirement and the agency's Six Year Review process. EPA also plans to...

Surface texture of resin-modified glass ionomer cements: effects of finishing/polishing systems.

PubMed

Yap, Adrian U J; Tan, W S; Yeo, J C; Yap, W Y; Ong, S B

2002-01-01

This study investigated the surface texture of two resin-modified glass ionomer cements (RMGICs) in the vertical and horizontal axis after treatment with different finishing/polishing systems. Class V preparations were made on the buccal and lingual/palatal surfaces of freshly extracted teeth. The cavities on each tooth were restored with Fuji II LC (GC) and Photac-Fil Quick (ESPE) according to manufacturers' instructions. Immediately after light-polymerization, gross finishing was done with 8-flute tungsten carbide burs. The teeth were then randomly divided into four groups and finished/polished with (a) Robot Carbides (RC); (b) Super-Snap system (SS); (c) OneGloss (OG) and (d) CompoSite Points (CS). The sample size for each material-finishing/polishing system combination was eight. The mean surface roughness (microm) in vertical (RaV) and horizontal (RaH) axis was measured using a profilometer. Data was subjected to ANOVA/Scheffe's tests and Independent Samples t-test at significance level 0.05. Mean RaV ranged from 0.59-1.31 and 0.83-1.52, while mean RaH ranged from 0.80-1.43 and 0.85-1.58 for Fuji II LC and Photac-Fil, respectively. Results of statistical analysis were as follows: Fuji II LC: RaV-RC, SSfinished with RC. The use of carbides (RC) and one-step rubber abrasive system (OG) for finishing/polishing of RMGICs is not recommended. Graded abrasive disk (SS) or two-step rubber abrasive (CS) systems should be used instead.

The research and realization of digital management platform for ultra-precision optical elements within life-cycle

NASA Astrophysics Data System (ADS)

Wang, Juan; Wang, Jian; Li, Lijuan; Zhou, Kun

2014-08-01

In order to solve the information fusion, process integration, collaborative design and manufacturing for ultra-precision optical elements within life-cycle management, this paper presents a digital management platform which is based on product data and business processes by adopting the modern manufacturing technique, information technique and modern management technique. The architecture and system integration of the digital management platform are discussed in this paper. The digital management platform can realize information sharing and interaction for information-flow, control-flow and value-stream from user's needs to offline in life-cycle, and it can also enhance process control, collaborative research and service ability of ultra-precision optical elements.

Superficial roughness on composite surface, composite-enamel and composite-dentin junctions after different finishing and polishing procedures. Part II: roughness with diamond finishing and differences between enamel composite vs body composite.

PubMed

Ferraris, Federico; Conti, Alessandro

2014-01-01

The following study asks three principle questions relative to composite finishing and composite polishing: 1) Will the superficial roughness of different restoration surfaces have different values, utilizing the same polishing system (multistep), after finishing with the tungsten carbide or diamond bur? 2) Under the same conditions of finishing and polishing sequences, will the composite surfaces (C), the composite-enamel (CE) and composite-dentin (CD) interfaces show different roughness values? 3) Will the surface roughness of composites of different translucency in the various phases of finishing and polishing, and on different interfaces, have different results? The null hypothesis is represented by the fact that there are no significant differences on roughness of composite restorations when polishing, after finishing with tungsten carbide or diamond burs. Furthermore, the null hypothesis is that there are no significant differences on roughness between polishing on composite surface, composite-enamel and composite-dentin interfaces, and finally there are no differences on roughness after finishing and polishing of two composite with different translucency. For the study, 56 class V cavities were prepared on extracted teeth. Restorations were done in nanofilled composite Filtek XTE (3M Espe) in a standard fashion, and then finished and polished. The 28 buccal cavities were restored on the surface with composite enamel and the 28 palatals with composite body. Finishing was done with fine toothing burs in tungsten carbide (16 blades) or fine grit diamond burs (46 μm), and made by the same manufacturer (Komet). The second phase of finishing was done with burs (with the same form as already mentioned) ultrafine toothing tungsten carbide (30 blades) or with extra and ultrafine grit diamond (25 and 8 μm). The polishing phase for both of the earlier sequences was done with the application of three rubber tips with decreasing abrasiveness and an application with a

Study on surface roughness evolvement of Nd-doped phosphate glass after IBF

NASA Astrophysics Data System (ADS)

Li, Furen; Xie, Xuhui; Zhou, Lin; Tie, Guipeng; Hu, Hao

2016-10-01

Nd doped phosphate glass is widely used as gain media in high power laser system. It is traditionally polished with the annular polishing technology. The edge effect is inevitable in annular polishing process and it results in the low manufacturing efficiency. Ion Beam Figuring (IBF) is a highly deterministic, non-contact method for the ultra-precision optics fabrication. So the edge effect is avoided. Nanometer and sub-nanometer precision is realizable in IBF. In this paper, Nd doped phosphate glass was polished with IBF, and the evolvement of surface roughness was emphasized. The roughness of surface polished with ion beam at normal and oblique incidence was researched. The oblique incident angle was 45°. The surface roughness was measured with the white light interferometer. No evident change was observed. This means that the pre-finish roughness can be preserved in IBF. The results denote that IBF is a feasible method to correct the contour errors of Nd doped phosphate glass, and the roughness will not be coarsened.

Evaluation of ENEPIG and Immersion Silver Surface Finishes Under Drop Loading

NASA Astrophysics Data System (ADS)

Pearl, Adam; Osterman, Michael; Pecht, Michael

2016-01-01

The effect of printed circuit board surface finish on the drop loading reliability of ball grid array (BGA) solder interconnects has been examined. The finishes examined include electroless nickel/electroless palladium/immersion gold (ENEPIG) and immersion silver (ImAg). For the ENEPIG finish, the effect of the Pd plating layer thickness was evaluated by testing two different thicknesses: 0.05 μm and 0.15 μm. BGA components were assembled onto the boards using either eutectic Sn-Pb or Sn-3.0Ag-0.5Cu (SAC305) solder. Prior to testing, the assembled boards were aged at 100°C for 24 h or 500 h. The boards were then subjected to multiple 1500-g drop tests. Failure analysis indicated the primary failure site for the BGAs to be the solder balls at the board-side solder interface. Cratering of the board laminate under the solder-attached pads was also observed. In all cases, isothermal aging reduced the number of drops to failure. The components soldered onto the boards with the 0.15- μm-Pd ENEPIG finish with the SAC305 solder had the highest characteristic life, at 234 drops to failure, compared with the other finish-solder combinations.

Electromigration Failure Mechanism in Sn-Cu Solder Alloys with OSP Cu Surface Finish

NASA Astrophysics Data System (ADS)

Chu, Ming-Hui; Liang, S. W.; Chen, Chih; Huang, Annie T.

2012-09-01

Organic solderable preservative (OSP) has been adopted as the Cu substrate surface finish in flip-chip solder joints for many years. In this study, the electromigration behavior of lead-free Sn-Cu solder alloys with thin-film under bump metallization and OSP surface finish was investigated. The results showed that severe damage occurred on the substrate side (cathode side), whereas the damage on the chip side (cathode side) was not severe. The damage on the substrate side included void formation, copper dissolution, and formation of intermetallic compounds (IMCs). The OSP Cu interface on the substrate side became the weakest point in the solder joint even when thin-film metallization was used on the chip side. Three-dimensional simulations were employed to investigate the current density distribution in the area between the OSP Cu surface finish and the solder. The results indicated that the current density was higher along the periphery of the bonding area between the solder and the Cu pad, consistent with the area of IMC and void formation in our experimental results.

Pb-free surface-finishing on electronic components' terminals for Pb-free soldering assembly

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

Tanaka, Hitoshi; Tanimoto, Morimasa; Matsuda, Akira

1999-11-01

Pb-free solderable surface finishing is essential to implement Pb-free solder assembly in order to meet with the growing demand of environmental consciousness to eliminate Pb from electronic products. Two types of widely applicable Pb-free surface finishing technologies are developed. One is the multilayer-system including Pd with Ni undercoat. Heat-resistance of Pd enables whole-surface-plating on to leadframe before IC-assembling process. The other is the double-layer-system with low-melting-point-materials, for example, thicker Sn underlayer and thinner Sn-Bi alloy overlayer, dilutes Sn-Bi alloy's defects of harmful reactivity along with substrate metal and mechanical brittleness with keeping its advantages of solder-wettability and no whisker.

Machining the Integral Impeller and Blisk of Aero-Engines: A Review of Surface Finishing and Strengthening Technologies

NASA Astrophysics Data System (ADS)

Fu, Youzhi; Gao, Hang; Wang, Xuanping; Guo, Dongming

2017-05-01

The integral impeller and blisk of an aero-engine are high performance parts with complex structure and made of difficult-to-cut materials. The blade surfaces of the integral impeller and blisk are functional surfaces for power transmission, and their surface integrity has significant effects on the aerodynamic efficiency and service life of an aero-engine. Thus, it is indispensable to finish and strengthen the blades before use. This paper presents a comprehensive literature review of studies on finishing and strengthening technologies for the impeller and blisk of aero-engines. The review includes independent and integrated finishing and strengthening technologies and discusses advanced rotational abrasive flow machining with back-pressure used for finishing the integral impeller and blisk. A brief assessment of future research problems and directions is also presented.

Mesoplasticity approach to studies of the cutting mechanism in ultra-precision machining

NASA Astrophysics Data System (ADS)

Lee, Rongbin W. B.; Wang, Hao; To, Suet; Cheung, Chi Fai; Chan, Chang Yuen

2014-03-01

There have been various theoretical attempts by researchers worldwide to link up different scales of plasticity studies from the nano-, micro- and macro-scale of observation, based on molecular dynamics, crystal plasticity and continuum mechanics. Very few attempts, however, have been reported in ultra-precision machining studies. A mesoplasticity approach advocated by Lee and Yang is adopted by the authors and is successfully applied to studies of the micro-cutting mechanisms in ultra-precision machining. Traditionally, the shear angle in metal cutting, as well as the cutting force variation, can only be determined from cutting tests. In the pioneering work of the authors, the use of mesoplasticity theory enables prediction of the fluctuation of the shear angle and micro-cutting force, shear band formation, chip morphology in diamond turning and size effect in nano-indentation. These findings are verified by experiments. The mesoplasticity formulation opens up a new direction of studies to enable how the plastic behaviour of materials and their constitutive representations in deformation processing, such as machining can be predicted, assessed and deduced from the basic properties of the materials measurable at the microscale.

Effect finishing and polishing procedures on the surface roughness of IPS Empress 2 ceramic.

PubMed

Boaventura, Juliana Maria Capelozza; Nishida, Rodrigo; Elossais, André Afif; Lima, Darlon Martins; Reis, José Mauricio Santos Nunes; Campos, Edson Alves; de Andrade, Marcelo Ferrarezi

2013-01-01

To evaluate the surface roughness of IPS Empress 2 ceramic when treated with different finishing/polishing protocols. Sixteen specimens of IPS Empress 2 ceramic were made from wax patterns obtained using a stainless steel split mold. The specimens were glazed (Stage 0-S0, control) and divided into two groups. The specimens in Group 1 (G1) were finished/polished with a KG Sorensen diamond point (S1), followed by KG Sorensen siliconized points (S2) and final polishing with diamond polish paste (S3). In Group 2 (G2), the specimens were finished/polished using a Shofu diamond point (S1), as well as Shofu siliconized points (S2) and final polishing was performed using Porcelize paste (S3). After glazing (S0) and following each polishing procedure (S1, S2 or S3), the surface roughness was measured using TALYSURF Series 2. The average surface roughness results were analyzed using ANOVA followed by Tukey post-hoc tests (α = 0.01) RESULTS: All of the polishing procedures yielded higher surface roughness values when compared to the control group (S0). S3 yielded lower surface roughness values when compared to S1 and S2. The proposed treatments negatively affected the surface roughness of the glazed IPS Empress 2 ceramic.

Production of Near-Mirror Surface Quality by Precision Grinding

NASA Technical Reports Server (NTRS)

Dimofte, Florin; Krantz, Timothy

2003-01-01

Mechanical components such as gears and bearings operate with the working surfaces in intimate contact with a mating part. The performance of such components will be influenced by the quality of the working surface. In general, a smoother surface will perform better than a rougher surface since the lubrication conditions are improved. For example, surfaces with a special near-mirror quality finish of low roughness performed better than ground surfaces when tested using a block-on-ring arrangement. Bearings with near-mirror quality have been tested and analyzed; lower running torques were measured and improved fatigue life was anticipated. Experiments have been done to evaluate the performance of gears with improved, low roughness surface finishing. The measured performance improvements include an increased scuffing (scoring) load capacity by a factor of 1.6, a 30-percent reduction of gear tooth running friction, and longer fatigue lives by a factor of about four. One can also anticipate that near-mirror quality surface finishing could improve the performance of other mechanical components such as mechanical seals and heavily loaded journal bearings. Given these demonstrated benefits, capable and economical methods for the production of mechanical components with near-mirror quality surfaces are desired. One could propose the production of near-mirror quality surfaces by several methods such as abrasive polishing, chemical assisted polishing, or grinding. Production of the surfaces by grinding offers the possibility to control the macro-geometry (form), waviness, and surface texture with one process. The present study was carried out to investigate the possibility of producing near-mirror quality surfaces by grinding. The present study makes use of a specially designed grinding machine spindle to improve the surface quality relative to the quality produced when using a spindle of conventional design.

No improvement in race performance by naps in male ultra-endurance cyclists in a 600-km ultra-cycling race.

PubMed

Knechtle, Beat; Wirth, Andrea; Knechtle, Patrizia; Rüst, Christoph Alexander; Rosemann, Thomas; Lepers, Romuald

2012-04-30

Ultra-endurance performance is of increasing popularity. We investigated the associations between anthropometry, training and support during racing, with race performance in 67 male recreational ultra-endurance cyclists participating in the 'Swiss Cycling Marathon' over 600 kilometres, an official qualifier for the cycling ultra-marathon 'Paris-Brest-Paris'. The 54 finishers showed no differences in anthropometry and did not train differently compared to the 13 non-finishers. During the race, the finishers were significantly more frequently racing alone than being followed by a support crew. After bivariate analysis, percent body fat (r = 0.43), the cycling distance per training unit (r = -0.36), the duration per training unit (r = -0.31) and the sleep time during the race (r = 0.50) were related to overall race time. The 23 non-sleepers in the finisher group completed the race within (mean and IQR) 1,567 (1,453-1,606) min, highly significantly faster than the 31 sleepers with 1,934 (1,615-2,033) min (P = 0.0003). No variable of support during the race was associated with race time. After multivariate analysis, percent body fat (P = 0.026) and duration per training unit (P = 0.005) remained predictor variables for race time. To summarize, for a successful finish in a cycling ultra-marathon over 600 kilometres such as the 'Swiss Cycling Marathon', percent body fat and duration per training unit were related to race time whereas equipment and support during the race showed no association. Athletes with naps were highly significantly slower than athletes without naps.

Research on error control and compensation in magnetorheological finishing.

PubMed

Dai, Yifan; Hu, Hao; Peng, Xiaoqiang; Wang, Jianmin; Shi, Feng

2011-07-01

Although magnetorheological finishing (MRF) is a deterministic finishing technology, the machining results always fall short of simulation precision in the actual process, and it cannot meet the precision requirements just through a single treatment but after several iterations. We investigate the reasons for this problem through simulations and experiments. Through controlling and compensating the chief errors in the manufacturing procedure, such as removal function calculation error, positioning error of the removal function, and dynamic performance limitation of the CNC machine, the residual error convergence ratio (ratio of figure error before and after processing) in a single process is obviously increased, and higher figure precision is achieved. Finally, an improved technical process is presented based on these researches, and the verification experiment is accomplished on the experimental device we developed. The part is a circular plane mirror of fused silica material, and the surface figure error is improved from the initial λ/5 [peak-to-valley (PV) λ=632.8 nm], λ/30 [root-mean-square (rms)] to the final λ/40 (PV), λ/330 (rms) just through one iteration in 4.4 min. Results show that a higher convergence ratio and processing precision can be obtained by adopting error control and compensation techniques in MRF.

Control of formaldehyde and TVOC emission from wood-based flooring composites at various manufacturing processes by surface finishing.

PubMed

Kim, Sumin

2010-04-15

This paper assesses the reproducibility of testing formaldehyde and TVOC emission behavior from wood flooring composites bonded by urea-formaldehyde resin at various manufacturing steps for surface finishing materials. The surface adhesion step of laminate flooring for this research was divided into two steps; HDF only and HDF with LPMs. In the case of engineered flooring, the manufacturing steps were divided into three steps; plywood only, fancy veneer bonded on plywood and UV coated on fancy veneer with plywood. Formaldehyde and VOCs emission decreased at the process of final surface finishing materials; LPMs were applied on the surface of HDF for laminate flooring. Although emissions increased when fancy veneer was bonded onto plywood in the case of engineered flooring, emission was dramatically reduced up to similar level with plywood only when final surface finishing; UV-curable coating was applied on fancy veneer. This study suggests that formaldehyde and VOCs emission from floorings can be controlled at manufacturing steps for surface finishing. 2009 Elsevier B.V. All rights reserved.

Ultra precision and reliable bonding method

NASA Technical Reports Server (NTRS)

Gwo, Dz-Hung (Inventor)

2001-01-01

The bonding of two materials through hydroxide-catalyzed hydration/dehydration is achieved at room temperature by applying hydroxide ions to at least one of the two bonding surfaces and by placing the surfaces sufficiently close to each other to form a chemical bond between them. The surfaces may be placed sufficiently close to each other by simply placing one surface on top of the other. A silicate material may also be used as a filling material to help fill gaps between the surfaces caused by surface figure mismatches. A powder of a silica-based or silica-containing material may also be used as an additional filling material. The hydroxide-catalyzed bonding method forms bonds which are not only as precise and transparent as optical contact bonds, but also as strong and reliable as high-temperature frit bonds. The hydroxide-catalyzed bonding method is also simple and inexpensive.

Challenges in mold manufacturing for high precision molded diffractive optical elements

NASA Astrophysics Data System (ADS)

Pongs, Guido; Bresseler, Bernd; Schweizer, Klaus; Bergs, Thomas

2016-09-01

Isothermal precision glass molding of imaging optics is the key technology for mass production of precise optical elements. Especially for numerous consumer applications (e.g. digital cameras, smart phones, …), high precision glass molding is applied for the manufacturing of aspherical lenses. The usage of diffractive optical elements (DOEs) can help to further reduce the number of lenses in the optical systems which will lead to a reduced weight of hand-held optical devices. But today the application of molded glass DOEs is limited due to the technological challenges in structuring the mold surfaces. Depending on the application submicrometer structures are required on the mold surface. Furthermore these structures have to be replicated very precisely to the glass lens surface. Especially the micro structuring of hard and brittle mold materials such as Tungsten Carbide is very difficult and not established. Thus a multitude of innovative approaches using diffractive optical elements cannot be realized. Aixtooling has investigated in different mold materials and different suitable machining technologies for the micro- and sub-micrometer structuring of mold surfaces. The focus of the work lays on ultra-precision grinding to generate the diffractive pattern on the mold surfaces. This paper presents the latest achievements in diffractive structuring of Tungsten Carbide mold surfaces by ultra-precision grinding.

Effect finishing and polishing procedures on the surface roughness of IPS Empress 2 ceramic

PubMed Central

Nishida, Rodrigo; Elossais, André Afif; Lima, Darlon Martins; Reis, José Mauricio Santos Nunes; Campos, Edson Alves; de Andrade, Marcelo Ferrarezi

2013-01-01

Objective. To evaluate the surface roughness of IPS Empress 2 ceramic when treated with different finishing/polishing protocols. Materials and methods. Sixteen specimens of IPS Empress 2 ceramic were made from wax patterns obtained using a stainless steel split mold. The specimens were glazed (Stage 0–S0, control) and divided into two groups. The specimens in Group 1 (G1) were finished/polished with a KG Sorensen diamond point (S1), followed by KG Sorensen siliconized points (S2) and final polishing with diamond polish paste (S3). In Group 2 (G2), the specimens were finished/polished using a Shofu diamond point (S1), as well as Shofu siliconized points (S2) and final polishing was performed using Porcelize paste (S3). After glazing (S0) and following each polishing procedure (S1, S2 or S3), the surface roughness was measured using TALYSURF Series 2. The average surface roughness results were analyzed using ANOVA followed by Tukey post-hoc tests (α = 0.01) Results. All of the polishing procedures yielded higher surface roughness values when compared to the control group (S0). S3 yielded lower surface roughness values when compared to S1 and S2. Conclusions. The proposed treatments negatively affected the surface roughness of the glazed IPS Empress 2 ceramic. PMID:22724660

The Effect of Composition on the Surface Finish of PS400: A New High Temperature Solid Lubricant Coating

NASA Technical Reports Server (NTRS)

DellaCorte, Christopher; Stanford, malcolm K.; Thomas, Fransua; Edmonds, Brian J.

2010-01-01

A new composite, multi-constituent, solid lubricant coating, NASA PS400, developed for high temperature tribological applications, exhibits a smoother surface finish after grinding and polishing than its predecessors PS200 and PS300. In this paper, the baseline composition of PS400 is modified to investigate each individual constituent s role on the achievable surface finish through a series of coating deposition, grinding, and polishing experiments. Furthermore, to explore the limits of compositional tailoring for improved tribological performance, several PS400 coatings were doped with additional solid lubricants (graphite, MoS2 and BN) and tribologically tested. The test results clearly showed that, compared to PS300 coatings, PS400 achieves a smoother surface finish via a reduced lubricant content. Coatings prepared with higher than the baseline level (10 wt%) of lubricants exhibited higher final surface roughness than the earlier generation PS300 coatings. Reducing or eliminating the one or both lubricants (fluorides or silver) did not further improve the surface finish suggesting that the current composition of PS400 is near optimal with respect to surface finish. Lastly, attempts to improve the poor initial room temperature tribological behavior of PS400 via the addition of traditional solid lubricants were unsuccessful. Based upon this work and earlier results it is expected that future research will concentrate on developing methods to produce a lubricious glaze on the rubbing surface during break in to ensure that low friction and wear are rapidly achieved.

Influence law of structural characteristics on the surface roughness of a magnetorheological-finished KDP crystal.

PubMed

Chen, Shaoshan; Li, Shengyi; Hu, Hao; Li, Qi; Tie, Guipeng

2014-11-01

A new nonaqueous and abrasive-free magnetorheological finishing (MRF) method is adopted for processing potassium dihydrogen phosphate (KDP) crystal due to its low hardness, high brittleness, temperature sensitivity, and water solubility. This paper researches the influence of structural characteristics on the surface roughness of MRF-finished KDP crystal. The material removal by dissolution is uniform layer by layer when the polishing parameters are stable. The angle between the direction of the polishing wheel's linear velocity and the initial turning lines will affect the surface roughness. If the direction is perpendicular to the initial turning lines, the polishing can remove the lines. If the direction is parallel to the initial turning lines, the polishing can achieve better surface roughness. The structural characteristic of KDP crystal is related to its internal chemical bonds due to its anisotropy. During the MRF finishing process, surface roughness will be improved if the structural characteristics of the KDP crystal are the same on both sides of the wheel. The processing results of (001) plane crystal show we can get the best surface roughness (RMS of 0.809 nm) if the directions of cutting and MRF polishing are along the (110) direction.

Surface finish of resin-modified and highly viscous glass ionomer cements produced by new one-step systems.

PubMed

Yap, Adrian U J; Ng, J J; Yap, S H; Teo, C K

2004-01-01

This study investigated the surface finish of resin-modified (Fuji II LC, GC) and highly viscous (Fuji IX GP Fast, GC) glass ionomer cements after treatment with three one-step finishing/polishing systems (One-Gloss [OG], Shofu; Pogo [PG], Dentsply; Sof-Lex Brush [SB], 3M-ESPE). The surface roughness obtained was compared to that using a matrix strip [MS], a two-step rubber abrasive (CompoSite [CS], Shofu) and a graded abrasive disk (Super Snap [SS], Shofu) system. Eight specimens (3-mm long x 3-mm wide x 2-mm deep) of each material were made for the various treatment groups. With the exception of the MS group, all groups were roughened with 320 grit grinding paper using a lapping device prior to finishing/polishing with the different systems. The mean surface roughness (microm) was measured with a profilometer. Data was subjected to ANOVA/Scheffe's tests at significance level 0.05. Mean Ra ranged from 0.13 to 1.04 microm for Fuji II LC and 0.14 to 0.81 for Fuji IX GP. For both materials, the smoothest surface was obtained with MS and the roughest with OG. Depending on the materials, the surface finish produced by PG and SB was superior or comparable to that obtained with CS and SS. The effectiveness of one-step systems, when used to finish/polish resin-modified and highly viscous glass ionomer cements, is product dependent.

Material removal in magnetorheological finishing of optics.

PubMed

Kordonski, William; Gorodkin, Sergei

2011-05-10

A concept of material removal based on the principle of conservation of particles momentum in a binary suspension is applied to analyze material removal in magnetorheological finishing and magnetorheological jet processes widely used in precision optics fabrication. According to this concept, a load for surface indentation by abrasive particles is provided at their interaction near the wall with heavier basic (magnetic) particles, which fluctuate (due to collision) in the shear flow of concentrated suspension. The model is in good qualitative and quantitative agreement with experimental results.

Generation Mechanism of Work Hardened Surface Layer in Metal Cutting

NASA Astrophysics Data System (ADS)

Hikiji, Rikio; Kondo, Eiji; Kawagoishi, Norio; Arai, Minoru

Finish machining used to be carried out in grinding, but it is being replaced by cutting with very small undeformed chip thickness. In ultra precision process, the effects of the cutting conditions and the complicated factors on the machined surface integrity are the serious problems. In this research, work hardened surface layer was dealt with as an evaluation of the machined surface integrity and the effect of the mechanical factors on work hardening was investigated experimentally in orthogonal cutting. As a result, it was found that work hardened surface layer was affected not only by the shear angle varied under the cutting conditions and the thrust force of cutting resistance, but also by the thrust force acting point, the coefficient of the thrust force and the compressive stress equivalent to the bulk hardness. Furthermore, these mechanical factors acting on the depth of the work hardened surface layer were investigated with the calculation model.

Surface quality and topographic inspection of variable compliance part after precise turning

NASA Astrophysics Data System (ADS)

Nieslony, P.; Krolczyk, G. M.; Wojciechowski, S.; Chudy, R.; Zak, K.; Maruda, R. W.

2018-03-01

The paper presents the problem of precise turning of the mould parts with variable compliance and demonstrates a topographic inspection of the machined surface quality. The study was conducted for the cutting tools made of cemented carbide with coatings, in a range of variable cutting parameters. The long shaft with special axial hole, made of hardened 55NiCrMoV6 steel was selected as a workpiece. The carried out study included the stiffness measurement of the machining system, as well as the investigation of cutting force components. In this context, the surface topography parameters were evaluated using the stylus profile meter and analysed. The research revealed that the surface topography, alongside the 3D functional parameters, and PSD influences the performance of the machined surface. The lowest surface roughness parameters values, equalled to Sa = 1 μm and Sz = 4.3 μm have been obtained during turning with cutting speed vc = 90 m/min. The stable turning of variable compliance part affects the surface texture formation with a unidirectional perpendicular, anisotropic structure. Nevertheless, in case of unstable turning, the characteristic chatter marks are observed, and process dynamics has greater contribution in formation of surface finish than turning kinematics and elastic plastic deformation of workpiece.

Research on precision grinding technology of large scale and ultra thin optics

NASA Astrophysics Data System (ADS)

Zhou, Lian; Wei, Qiancai; Li, Jie; Chen, Xianhua; Zhang, Qinghua

2018-03-01

The flatness and parallelism error of large scale and ultra thin optics have an important influence on the subsequent polishing efficiency and accuracy. In order to realize the high precision grinding of those ductile elements, the low deformation vacuum chuck was designed first, which was used for clamping the optics with high supporting rigidity in the full aperture. Then the optics was planar grinded under vacuum adsorption. After machining, the vacuum system was turned off. The form error of optics was on-machine measured using displacement sensor after elastic restitution. The flatness would be convergenced with high accuracy by compensation machining, whose trajectories were integrated with the measurement result. For purpose of getting high parallelism, the optics was turned over and compensation grinded using the form error of vacuum chuck. Finally, the grinding experiment of large scale and ultra thin fused silica optics with aperture of 430mm×430mm×10mm was performed. The best P-V flatness of optics was below 3 μm, and parallelism was below 3 ″. This machining technique has applied in batch grinding of large scale and ultra thin optics.

Analysis and control on changeable wheel tool system of hybrid grinding and polishing machine tool for blade finishing

NASA Astrophysics Data System (ADS)

He, Qiuwei; Lv, Xingming; Wang, Xin; Qu, Xingtian; Zhao, Ji

2017-01-01

Blade is the key component in the energy power equipment of turbine, aircraft engines and so on. Researches on the process and equipment for blade finishing become one of important and difficult point. To control precisely tool system of developed hybrid grinding and polishing machine tool for blade finishing, the tool system with changeable wheel for belt polishing is analyzed in this paper. Firstly, the belt length and wrap angle of each wheel in different position of tension wheel swing angle in the process of changing wheel is analyzed. The reasonable belt length is calculated by using MATLAB, and relationships between wrap angle of each wheel and cylinder expansion amount of contact wheel are obtained. Then, the control system for changeable wheel tool structure is developed. Lastly, the surface roughness of blade finishing is verified by experiments. Theoretical analysis and experimental results show that reasonable belt length and wheel wrap angle can be obtained by proposed analysis method, the changeable wheel tool system can be controlled precisely, and the surface roughness of blade after grinding meets the design requirements.

Effect of Gold on the Corrosion Behavior of an Electroless Nickel/Immersion Gold Surface Finish

NASA Astrophysics Data System (ADS)

Bui, Q. V.; Nam, N. D.; Yoon, J. W.; Choi, D. H.; Kar, A.; Kim, J. G.; Jung, S. B.

2011-09-01

The performance of surface finishes as a function of the pH of the utilized plating solution was evaluated by electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization tests in 3.5 wt.% NaCl solution. In addition, the surface finishes were examined by x-ray diffraction (XRD), and the contact angle of the liquid/solid interface was recorded. NiP films on copper substrates with gold coatings exhibited their highest coating performance at pH 5. This was attributed to the films having the highest protective efficiency and charge transfer resistance, lowest porosity value, and highest contact angle among those examined as a result of the strongly preferred Au(111) orientation and the improved surface wettability.

Ultra-High Surface Speed for Metal Removal, Artillery Shell

DTIC Science & Technology

1981-07-01

TECHNICAL LIBRARY "y/a^^cr^ AD-E400 660 CONTRACTOR REPORT ARLCD-CR- 81019 ULTRA-HIGH SURFACE SPEED FOR METAL REMOVAL, ARTILLERY SHELL RICHARD F...Report ARLCD-CR- 81019 2. GOVT ACCESSION NO. 3. RECIPIENT’S CATALOG NUMBER 4. TITLE (and Subtitle) ULTRA-HIGH SURFACE SPEED FOR METAL...UNIT* tuiPPtO 1 MIL -STD-43CA i, ASTM A-274-64 EF A1SI~1340 SEHI FIN FORGING STEEL 6 RC SQ ■ IP 120093* a LIFTS 38 PCS

Corrosion of RoHS-Compliant Surface Finishes in Corrosive Mixed Flowing Gas Environments

NASA Astrophysics Data System (ADS)

Hannigan, K.; Reid, M.; Collins, M. N.; Dalton, E.; Xu, C.; Wright, B.; Demirkan, K.; Opila, R. L.; Reents, W. D.; Franey, J. P.; Fleming, D. A.; Punch, J.

2012-03-01

Recently, the corrosion resistance of printed wiring board (PWB) finishes has generated considerable interest due to field failures observed in various parts of the world. This study investigates the corrosion issues associated with the different lead-free PWB surface finishes. Corrosion products on various PWB surface finishes generated in mixed flowing gas (MFG) environments were studied, and analysis techniques such as scanning electron microscopy, energy-dispersive x-ray, x-ray diffraction, focused ion beam, and scanning Auger microscopy were used to quantify the corrosion layer thickness and determine the composition of corrosion products. The corrosion on organic solderability preservative samples shows similar corrosion products to bare copper and is mainly due to direct attack of copper traces by corrosive gases. The corrosion on electroless nickel immersion gold occurs primarily through the porosity in the film and is accelerated by the galvanic potential between gold and copper; similar results were observed on immersion silver. Immersion tin shows excellent corrosion resistance due to its inherent corrosion resistance in the MFG environment as well as the opposite galvanic potential between tin and copper compared with gold or silver and copper.

On the properties of two binary NiTi shape memory alloys. Effects of surface finish on the corrosion behaviour and in vitro biocompatibility.

PubMed

Es-Souni, Mohammed; Es-Souni, Martha; Fischer-Brandies, Helge

2002-07-01

The present paper compares the transformation behaviour and mechanical properties of two orthodontic wires of close chemical compositions. The effects of surface topography and surface finish residues on the potentiodynamic corrosion behaviour and biocompatibility are also reported. The cytotoxicity tests were performed on both alloys in fibroblast cell cultures from human gingiva using the MTT test. It is shown that the surface finish and the amounts of surface finish residues affect dramatically the corrosion resistance. Bad surface finish results in lower corrosion resistance. The in vitro biocompatibility, though not affected to the extent of corrosion resistance, is also reduced as the surface roughness and the amounts of residues increase. This is thought to be due to surface effects on corrosion and metallic ions release.

Subsurface damage and microstructure development in precision microground hard ceramics using magnetorheological finishing spots.

PubMed

Shafrir, Shai N; Lambropoulos, John C; Jacobs, Stephen D

2007-08-01

We demonstrate the use of spots taken with magnetorheological finishing (MRF) for estimating subsurface damage (SSD) depth from deterministic microgrinding for three hard ceramics: aluminum oxynitride (Al(23)O(27)N(5)/ALON), polycrystalline alumina (Al(2)O(3)/PCA), and chemical vapor deposited (CVD) silicon carbide (Si(4)C/SiC). Using various microscopy techniques to characterize the surfaces, we find that the evolution of surface microroughness with the amount of material removed shows two stages. In the first, the damaged layer and SSD induced by microgrinding are removed, and the surface microroughness reaches a low value. Peak-to-valley (p-v) surface microroughness induced from grinding gives a measure of the SSD depth in the first stage. With the removal of additional material, a second stage develops, wherein the interaction of MRF and the material's microstructure is revealed. We study the development of this texture for these hard ceramics with the use of power spectral density to characterize surface features.

Subsurface Damage and Microstructure Development in Precision Microground Hard Ceramics Using Magnetorheological Finishing Spots

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

Shafrir, S.N.; Lambropoulos, J.C.; Jacobs, S.D.

2007-08-01

We demonstrate the use of spots taken with magnetorheological finishing (MRF) for estimating subsurface damage (SSD) depth from deterministic microgrinding for three hard ceramics: aluminum oxynitride (Al23O27N5/ALON), polycrystalline alumina (AL2O3/PCA), and chemical vapor deposited (CVD) silicon carbide (Si4C/SiC). Using various microscopy techniques to characterize the surfaces, we find that the evolution of surface microroughness with the amount of material removed shows two stages. In the first, the damaged layer and SSD induced by microgrinding are removed, and the surface roughness reaches a low value. Peak-to-valley (p-v) surface microroughness induced from grinding gives a measure of the SSD depth in themore » first stage. With the removal of additional material, a second stage develops, wherein the interaction of MRF and the material's microstructure is revealed. We study the development of this texture for these har ceramics with the use of power spectral density to characterize surface features.« less

Designable ultra-smooth ultra-thin solid-electrolyte interphases of three alkali metal anodes.

PubMed

Gu, Yu; Wang, Wei-Wei; Li, Yi-Juan; Wu, Qi-Hui; Tang, Shuai; Yan, Jia-Wei; Zheng, Ming-Sen; Wu, De-Yin; Fan, Chun-Hai; Hu, Wei-Qiang; Chen, Zhao-Bin; Fang, Yuan; Zhang, Qing-Hong; Dong, Quan-Feng; Mao, Bing-Wei

2018-04-09

Dendrite growth of alkali metal anodes limited their lifetime for charge/discharge cycling. Here, we report near-perfect anodes of lithium, sodium, and potassium metals achieved by electrochemical polishing, which removes microscopic defects and creates ultra-smooth ultra-thin solid-electrolyte interphase layers at metal surfaces for providing a homogeneous environment. Precise characterizations by AFM force probing with corroborative in-depth XPS profile analysis reveal that the ultra-smooth ultra-thin solid-electrolyte interphase can be designed to have alternating inorganic-rich and organic-rich/mixed multi-layered structure, which offers mechanical property of coupled rigidity and elasticity. The polished metal anodes exhibit significantly enhanced cycling stability, specifically the lithium anodes can cycle for over 200 times at a real current density of 2 mA cm -2 with 100% depth of discharge. Our work illustrates that an ultra-smooth ultra-thin solid-electrolyte interphase may be robust enough to suppress dendrite growth and thus serve as an initial layer for further improved protection of alkali metal anodes.

Comparison of different finishing/polishing systems on surface roughness and gloss of resin composites.

PubMed

Antonson, Sibel A; Yazici, A Rüya; Kilinc, Evren; Antonson, Donald E; Hardigan, Patrick C

2011-07-01

The aim of this study was to compare four finishing/polishing systems (F/P) on surface roughness and gloss of different resin composites. A total of 40 disc samples (15 mm × 3 mm) were prepared from a nanofill - Filtek Supreme Plus (FS) and a micro-hybrid resin composite - Esthet-X (EX). Following 24h storage in 37°C water, the top surfaces of each sample were roughened using 120-grit sandpaper. Baseline measurements of surface roughness (Ra, μm) and gloss were recorded. Each composite group was divided into four F/P disk groups: Astropol[AP], Enhance/PoGo[EP], Sof-Lex[SL], and an experimental disk system, EXL-695[EXL] (n=5). The same operator finished/polished all samples. One sample from each group was evaluated under SEM. Another blinded-operator conducted postoperative measurements. Results were analysed by two-way ANOVA, two interactive MANOVA and Tukey's t-test (p<0.05). In surface roughness, the baseline of two composites differed significantly from each other whereas postoperatively there was no significance. The Sof-Lex F/P system provided the smoothest surface although there were no statistical significance differences between F/P systems (p>0.01). In gloss, FS composite with the EXL-695 system provided a significantly higher gloss (p<0.01). EX treated by Soflex revealed the least gloss (p<0.05). SEM images revealed comparable results for F/P systems but EX surfaces included more air pockets. Four different finishing/polishing systems provided comparable surface smoothness for both composites, whereas EXL with FS provided significantly higher gloss. SEM evaluations revealed that the EX surface contained more air pockets but F/P systems were compatible. Copyright © 2011 Elsevier Ltd. All rights reserved.

A new Ultra Precision Interferometer for absolute length measurements down to cryogenic temperatures

NASA Astrophysics Data System (ADS)

Schödel, R.; Walkov, A.; Zenker, M.; Bartl, G.; Meeß, R.; Hagedorn, D.; Gaiser, C.; Thummes, G.; Heltzel, S.

2012-09-01

A new Ultra Precision Interferometer (UPI) was built at Physikalisch-Technische Bundesanstalt. As its precursor, the precision interferometer, it was designed for highly precise absolute length measurements of prismatic bodies, e.g. gauge blocks, under well-defined temperature conditions and pressure, making use of phase stepping imaging interferometry. The UPI enables a number of enhanced features, e.g. it is designed for a much better lateral resolution and better temperature stability. In addition to the original concept, the UPI is equipped with an external measurement pathway (EMP) in which a prismatic body can be placed alternatively. The temperature of the EMP can be controlled in a much wider range compared to the temperature of the interferometer's main chamber. An appropriate cryostat system, a precision temperature measurement system and improved imaging interferometry were established to permit absolute length measurements down to cryogenic temperature, demonstrated for the first time ever. Results of such measurements are important for studying thermal expansion of materials from room temperature towards less than 10 K.

Mach 5 electroformed nickel nozzle refurbishment FNAS investigation of ultra-smooth surfaces

NASA Technical Reports Server (NTRS)

Rood, Robert; Griffith, Charles; Engelhaupt, Darell

1992-01-01

This task is in support of the Quiet Hypersonic Wind Tunnel effort currently in effect at NASA Langley Research Center, VA. A laminar flow wind tunnel nozzle has been previously fabricated by electroforming pure nickel over a machined and polished two piece stainless steel mandrel. The mandrel was removed leaving the replicate nozzle surface. The nozzle was then pressed into a heavy stainless steel jacket for mounting features and rigidity. The original nickel surface was a replication of the polished mandrel but had degraded due to oxidation. The inside surface requirements are very stringent in order to achieve laminar or quiet flow at the desired pressure and temperature for the specific design of Mach 5. The throat area of the axisymmetric device must have a surface finish with no defects greater than 16 microinches. This requires an rms average background of about four microinches or better for inspection purposes. A coating of nickel-phosphorous alloy was applied by catalytic deposition and then the inside of the nozzle was polished retaining dimensional and surface finish tolerances as specified per drawings supplied. Since the unit is not an optical component, conventional optical inspection methods for surface finish and figure are not readily achieved. Measurements were made using surface profilometry.

Effect of cutting parameters on surface finish and machinability of graphite reinforced Al-8011 matrix composite

NASA Astrophysics Data System (ADS)

Anil, K. C.; Vikas, M. G.; Shanmukha Teja, B.; Sreenivas Rao, K. V.

2017-04-01

Many materials such as alloys, composites find their applications on the basis of machinability, cost and availability. In the present work, graphite (Grp) reinforced Aluminium 8011 is synthesized by convention stir casting process and Surface finish & machinability of prepared composite is examined by using lathe tool dynamometer attached with BANKA Lathe by varying the machining parameters like spindle speed, Depth of cut and Feed rate in 3 levels. Also, Roughness Average (Ra) of machined surfaces is measured by using Surface Roughness Tester (Mitutoyo SJ201). From the studies it is cleared that mechanical properties of a composites increases with addition of Grp and The cutting force were decreased with the reinforcement percentage and thus increases the machinability of composites and also results in increased surface finish.

Technologies for precision manufacture of current and future windows and domes

NASA Astrophysics Data System (ADS)

Hallock, Bob; Shorey, Aric

2009-05-01

The final finish and characterization of windows and domes presents a number of challenges in achieving desired precision with acceptable cost and schedule. This becomes more difficult with advanced materials and as window and dome shapes and requirements become more complex, including acute angle corners, transmitted wavefront specifications, aspheric geometries and trending toward conformal surfaces. Magnetorheological Finishing (MRF®) and Magnetorheological Jet (MR Jet®), along with metrology provided by Sub-aperture Stitching Interferometry (SSI®) have several unique attributes that provide them advantages in enhancing fabrication of current and next generation windows and domes. The advantages that MRF brings to the precision finishing of a wide range of shapes such as flats, spheres (including hemispheres), cylinders, aspheres and even freeform optics, has been well documented. Recent advancements include the ability to finish freeform shapes up to 2-meters in size as well as progress in finishing challenging IR materials. Due to its shear-based removal mechanism in contrast to the pressure-based process of other techniques, edges are not typically rolled, in particular on parts with acute angle corners. MR Jet provides additional benefits, particularly in the finishing of the inside of steep concave domes and other irregular shapes. The ability of MR Jet to correct the figure of conformal domes deterministically and to high precision has been demonstrated. Combining these technologies with metrology techniques, such as SSI provides a solution for finishing current and future windows and domes in a reliable, deterministic and cost-effective way. The ability to use the SSI to characterize a range of shapes such as domes and aspheres, as well as progress in using MRF and MR Jet for finishing conventional and conformal windows and domes with increasing size and complexity of design will be presented.

Effects of PCB Substrate Surface Finish, Flux, and Phosphorus Content on Ionic Contamination

NASA Astrophysics Data System (ADS)

Bacior, M.; Sobczak, N.; Siewiorek, A.; Kudyba, A.; Homa, M.; Nowak, R.; Dziula, M.; Masłoń, S.

2015-02-01

The ionic contamination on printed circuit boards (PCB) having different surface finishes was examined using ionograph. The study was performed at the RT on three types of PCBs covered with: (i) hot air solder leveling (HASL LF), (ii) electroless nickel immersion gold (ENIG), and (iii) organic surface protectant (OSP), all on Cu substrates, as well as two types of fluxes, namely EF2202 and RF800. In the group of boards without soldered components, the lowest average value of contamination was for the ENIG 18 µm surface (0.01 μg NaCl/cm2). Boards with soldered components were more contaminated (from 0.29 μg NaCl/cm2 for the HASL LF 18 µm surface). After spraying boards with fluxing agents, the values of contaminants were the highest. The influence of phosphorus content in Ni-P layer of ENIG finish on ionic contamination was examined. In the group of PCBs with Au coating, the smallest amount of surface contaminants (0.32 μg NaCl/cm2) was for Ni-2-5%P layer. PCBs with Ni-11%P layer were higher contaminated (0.47 μg NaCl/cm2), and another with Ni-8%P layer had 0.81 μg NaCl/cm2. PCBs without Au coating, had the lowest contamination (0.48 μg NaCl/cm2) at phosphorous content equal 11%P. Higher contamination (0.67 μg NaCl/cm2) was at 2-5%P, up to 1.98 μg NaCl/cm2 for 8% of P. Boards with Au finish have lower value of contamination than identical boards without Au layer thus contributing to better reliability of electronic assemblies, since its failures due to current leakage and corrosion can be caused by contaminants.

Ultra-High Precision Half-Life Measurement for the Superallowed &+circ; Emitter ^26Al^m

NASA Astrophysics Data System (ADS)

Finlay, P.; Demand, G.; Garrett, P. E.; Leach, K. G.; Phillips, A. A.; Sumithrarachchi, C. S.; Svensson, C. E.; Triambak, S.; Grinyer, G. F.; Leslie, J. R.; Andreoiu, C.; Cross, D.; Austin, R. A. E.; Ball, G. C.; Bandyopadhyay, D.; Djongolov, M.; Ettenauer, S.; Hackman, G.; Pearson, C. J.; Williams, S. J.

2009-10-01

The calculated nuclear structure dependent correction for ^26Al^m (δC-δNS= 0.305(27)% [1]) is smaller by nearly a factor of two than the other twelve precision superallowed cases, making it an ideal case to pursue a reduction in the experimental errors contributing to the Ft value. An ultra-high precision half-life measurement for the superallowed &+circ; emitter ^26Al^m has been made at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF in Vancouver, Canada. A beam of ˜10^5 ^26Al^m/s was delivered in October 2007 and its decay was observed using a 4π continuous gas flow proportional counter as part of an ongoing experimental program in superallowed Fermi β decay studies. With a statistical precision of ˜0.008%, the present work represents the single most precise measurement of any superallowed half-life to date. [4pt] [1] I.S. Towner and J.C. Hardy, Phys. Rev. C 79, 055502 (2009).

Ultra-High Precision Half-Life Measurement for the Superallowed &+circ; Emitter ^26Al^m

NASA Astrophysics Data System (ADS)

Finlay, P.; Demand, G.; Garrett, P. E.; Leach, K. G.; Phillips, A. A.; Sumithrarachchi, C. S.; Svensson, C. E.; Triambak, S.; Ball, G. C.; Bandyopadhyay, D.; Djongolov, M.; Ettenauer, S.; Hackman, G.; Pearson, C. J.; Williams, S. J.; Andreoiu, C.; Cross, D.; Austin, R. A. E.; Grinyer, G. F.; Leslie, J. R.

2008-10-01

The calculated nuclear structure dependent correction for ^26Al^m (δC-δNS= 0.305(27)% [1]) is smaller by nearly a factor of two than the other twelve precision superallowed cases, making it an ideal case to pursue a reduction in the experimental errors contributing to the Ft value. An ultra-high precision half-life measurement for the superallowed &+circ; emitter ^26Al^m has been made using a 4π continuous gas flow proportional counter as part of an ongoing experimental program in superallowed Fermi β decay studies at the Isotope Separator and Accelerator (ISAC) facility at TRIUMF in Vancouver, Canada, which delivered a beam of ˜10^5 ^26Al^m/s in October 2007. With a statistical precision of ˜0.008%, the present work represents the single most precise measurement of any superallowed half-life to date. [1] I.S. Towner and J.C. Hardy, Phys. Rev. C 77, 025501 (2008).

Printed Circuit Board Surface Finish and Effects of Chloride Contamination, Electric Field, and Humidity on Corrosion Reliability

NASA Astrophysics Data System (ADS)

Conseil-Gudla, Hélène; Jellesen, Morten S.; Ambat, Rajan

2017-02-01

Corrosion reliability is a serious issue today for electronic devices, components, and printed circuit boards (PCBs) due to factors such as miniaturization, globalized manufacturing practices which can lead to process-related residues, and global usage effects such as bias voltage and unpredictable user environments. The investigation reported in this paper focuses on understanding the synergistic effect of such parameters, namely contamination, humidity, PCB surface finish, pitch distance, and potential bias on leakage current under different humidity levels, and electrochemical migration probability under condensing conditions. Leakage currents were measured on interdigitated comb test patterns with three different types of surface finish typically used in the electronics industry, namely gold, copper, and tin. Susceptibility to electrochemical migration was studied under droplet conditions. The level of base leakage current (BLC) was similar for the different surface finishes and NaCl contamination levels up to relative humidity (RH) of 65%. A significant increase in leakage current was found for comb patterns contaminated with NaCl above 70% to 75% RH, close to the deliquescent RH of NaCl. Droplet tests on Cu comb patterns with varying pitch size showed that the initial BLC before dendrite formation increased with increasing NaCl contamination level, whereas electrochemical migration and the frequency of dendrite formation increased with bias voltage. The effect of different surface finishes on leakage current under humid conditions was not very prominent.

A new reactive atom plasma technology (RAPT) for precision machining: the etching of ULE optical surfaces

NASA Astrophysics Data System (ADS)

Fanara, Carlo; Shore, Paul; Nicholls, John R.; Lyford, Nicholas; Sommer, Phil; Fiske, Peter

2006-06-01

The next generation of 30-100 metre diameter extremely large telescopes (ELTs) requires large numbers of hexagonal primary mirror segments. As part of the Basic Technology programme run jointly by UCL and Cranfield University, a reactive atomic plasma technology (RAP(tm)) emerged from the US Lawrence Livermore National Laboratory (LLNL), is employed for the finishing of these surfaces. Results are presented on this novel etching technology. The Inductively Coupled Plasma (ICP) operated at atmospheric pressure using argon, activates the chemical species injected through its centre and promotes the fluorine-based chemical reactions at the surface. Process assessment trials on Ultra Low Expansion (ULE(tm)) plates, previously ground at high material removal rates, have been conducted. The quality of the surfaces produced on these samples using the RAP process are discussed. Substantial volumetric material removal rates of up to 0.446(21) mm 3/s at the highest process speed (1,200 mm/min) were found to be possible without pre-heating the substrate. The influences of power transfer, process speed and gas concentration on the removal rates have been determined. The suitability of the RAP process for revealing and removing sub-surface damage induced by high removal rate grinding is discussed. The results on SiC samples are reported elsewhere in this conference.

Analysis of the application of poly-nanocrystalline diamond tools for ultra precision machining of steel with ultrasonic assistance

NASA Astrophysics Data System (ADS)

Doetz, M.; Dambon, O.; Klocke, F.; Bulla, B.; Schottka, K.; Robertson, D. J.

2017-10-01

Ultra-precision diamond turning enables the manufacturing of parts with mirror-like surfaces and highest form accuracies out of non-ferrous, a few crystalline and plastic materials. Furthermore, an ultrasonic assistance has the ability to push these boundaries and enables the machining of materials like steel, which is not possible in a conventional way due to the excessive tool wear caused by the affinity of carbon to iron. Usually monocrystalline diamonds tools are applied due to their unsurpassed cutting edge properties. New cutting tool material developments have shown that it is possible to produce tools made of nano-polycrystalline diamonds with cutting edges equivalent to monocrystalline diamonds. In nano-polycrystalline diamonds ultra-fine grains of a few tens of nanometers are firmly and directly bonded together creating an unisotropic structure. The properties of this material are described to be isotropic, harder and tougher than those of the monocrystalline diamonds, which are unisotropic. This publication will present machining results from the newest investigations of the process potential of this new polycrystalline cutting material. In order to provide a baseline with which to characterize the cutting material cutting experiments on different conventional machinable materials like Cooper or Aluminum are performed. The results provide information on the roughness and the topography of the surface focusing on the comparison to the results while machining with monocrystalline diamond. Furthermore, the cutting material is tested in machining steel with ultrasonic assistance with a focus on tool life time and surface roughness. An outlook on the machinability of other materials will be given.

LLNL/Lion Precision LVDT amplifier

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

Hopkins, D.J.

1994-04-01

A high-precision, low-noise, LVDT amplifier has been developed which is a significant advancement on the current state of the art in contact displacement measurement. This amplifier offers the dynamic range of a typical LVDT probe but with a resolution that rivals that of non contact displacement measuring systems such as capacitance gauges and laser interferometers. Resolution of 0.1 {mu} in with 100 Hz bandwidth is possible. This level of resolution is over an order of magnitude greater than what is now commercially available. A front panel switch can reduce the bandwidth to 2.5 Hz and attain a resolution of 0.025more » {mu} in. This level of resolution meets or exceeds that of displacement measuring laser interferometry or capacitance gauge systems. Contact displacement measurement offers high part spatial resolution and therefore can measure not only part contour but surface finish. Capacitance gauges and displacement laser interferometry offer poor part spatial resolution and can not provide good surface finish measurements. Machine tool builders, meteorologists and quality inspection departments can immediately utilize the higher accuracy and capabilities that this amplifier offers. The precision manufacturing industry can improve as a result of improved capability to measure parts that help reduce costs and minimize material waste.« less

The estimation of dynamic contact angle of ultra-hydrophobic surfaces using inclined surface and impinging droplet methods

NASA Astrophysics Data System (ADS)

Jasikova, Darina; Kotek, Michal

2014-03-01

The development of industrial technology also brings with optimized surface quality, particularly where there is contact with food. Application ultra-hydrophobic surface significantly reduces the growth of bacteria and facilitates cleaning processes. Testing and evaluation of surface quality are used two methods: impinging droplet and inclined surface method optimized with high speed shadowgraphy, which give information about dynamic contact angle. This article presents the results of research into new methods of measuring ultra-hydrophobic patented technology.

CONTROL OF CHELATOR-BASED UPSETS IN SURFACE FINISHING SHOP WASTE WATER TREATMENT SYSTEMS

EPA Science Inventory

Actual surface finishing shop examples are used to illustrate the use of process chemistry understanding and analyses to identify immediate, interim and permanent response options for industrial waste water treatment plant (IWTP) upset problems caused by chelating agents. There i...

Mechanical Reliability of the Epoxy Sn-58wt.%Bi Solder Joints with Different Surface Finishes Under Thermal Shock

NASA Astrophysics Data System (ADS)

Sung, Yong-Gue; Myung, Woo-Ram; Jeong, Haksan; Ko, Min-Kwan; Moon, Jeonghoon; Jung, Seung-Boo

2018-04-01

The effect of thermal shock on the mechanical reliability of epoxy Sn-58wt.%Bi composite (epoxy Sn-58wt.%Bi) solder joints was investigated with different surface-finished substrates. Sn-58wt.%Bi-based solder has been considered as a promising candidate for low-temperature solder among various lead-free solders. However, Sn-58wt.%Bi solder joints can be easily broken under impact conditions such as mechanical shock, drop tests, and bending tests because of their poor ductility. Therefore, previous researchers have tried to improve the mechanical property of Sn-58wt.%Bi solder by additional elements and mixtures of metal powder and epoxy resin. Epoxy Sn-58wt.%Bi solder paste was fabricated by mixing epoxy resin and Sn-58wt.%Bi solder powder to enhance the mechanical reliability of Sn-58wt.%Bi solder joints. The epoxy Sn-58wt.%Bi solder paste was screen-printed onto various printed circuit board surfaces finished with organic solder preservatives (OSP), electroless nickel immersion gold (ENIG), and electroless nickel electroless palladium immersion gold (ENEPIG). The test components were prepared by a reflow process at a peak temperature of 190°C. The thermal shock test was carried out under the temperature range of - 40 to 125°C to evaluate the reliability of Sn-58wt.%Bi and epoxy Sn-58wt.%Bi solder joints. The OSP-finished sample showed a relatively higher mechanical property than those of ENIG and ENEPIG after thermal shock. The average number of cycles for epoxy Sn-58wt.%Bi solder with the OSP surface finish were 6 times higher than that for Sn-58wt.%Bi solder with the same finish. The microstructures of the solder joints were investigated by scanning electron microscopy, and the composition of the intermetallic compound (IMC) layer was analyzed by using energy dispersive spectrometry. Cu6Sn5 IMC was formed by the reaction between Sn-58wt.%Bi solder and a OSP surface-finished Cu after the reflow process. Ni3Sn4 IMC and (Ni, Pd)3Sn4 IMC were formed at the solder

Mechanical Reliability of the Epoxy Sn-58wt.%Bi Solder Joints with Different Surface Finishes Under Thermal Shock

NASA Astrophysics Data System (ADS)

Sung, Yong-Gue; Myung, Woo-Ram; Jeong, Haksan; Ko, Min-Kwan; Moon, Jeonghoon; Jung, Seung-Boo

2018-07-01

The effect of thermal shock on the mechanical reliability of epoxy Sn-58wt.%Bi composite (epoxy Sn-58wt.%Bi) solder joints was investigated with different surface-finished substrates. Sn-58wt.%Bi-based solder has been considered as a promising candidate for low-temperature solder among various lead-free solders. However, Sn-58wt.%Bi solder joints can be easily broken under impact conditions such as mechanical shock, drop tests, and bending tests because of their poor ductility. Therefore, previous researchers have tried to improve the mechanical property of Sn-58wt.%Bi solder by additional elements and mixtures of metal powder and epoxy resin. Epoxy Sn-58wt.%Bi solder paste was fabricated by mixing epoxy resin and Sn-58wt.%Bi solder powder to enhance the mechanical reliability of Sn-58wt.%Bi solder joints. The epoxy Sn-58wt.%Bi solder paste was screen-printed onto various printed circuit board surfaces finished with organic solder preservatives (OSP), electroless nickel immersion gold (ENIG), and electroless nickel electroless palladium immersion gold (ENEPIG). The test components were prepared by a reflow process at a peak temperature of 190°C. The thermal shock test was carried out under the temperature range of - 40 to 125°C to evaluate the reliability of Sn-58wt.%Bi and epoxy Sn-58wt.%Bi solder joints. The OSP-finished sample showed a relatively higher mechanical property than those of ENIG and ENEPIG after thermal shock. The average number of cycles for epoxy Sn-58wt.%Bi solder with the OSP surface finish were 6 times higher than that for Sn-58wt.%Bi solder with the same finish. The microstructures of the solder joints were investigated by scanning electron microscopy, and the composition of the intermetallic compound (IMC) layer was analyzed by using energy dispersive spectrometry. Cu6Sn5 IMC was formed by the reaction between Sn-58wt.%Bi solder and a OSP surface-finished Cu after the reflow process. Ni3Sn4 IMC and (Ni, Pd)3Sn4 IMC were formed at the solder

Magnetorheological finishing for removing surface and subsurface defects of fused silica optics

NASA Astrophysics Data System (ADS)

Catrin, Rodolphe; Neauport, Jerome; Taroux, Daniel; Cormont, Philippe; Maunier, Cedric; Lambert, Sebastien

2014-09-01

We investigate the capacity of magnetorheological finishing (MRF) process to remove surface and subsurface defects of fused silica optics. Polished samples with engineered surface and subsurface defects were manufactured and characterized. Uniform material removals were performed with a QED Q22-XE machine using different MRF process parameters in order to remove these defects. We provide evidence that whatever the MRF process parameters are, MRF is able to remove surface and subsurface defects. Moreover, we show that MRF induces a pollution of the glass interface similar to conventional polishing processes.

Physiology and Pathophysiology in Ultra-Marathon Running

PubMed Central

Knechtle, Beat; Nikolaidis, Pantelis T.

2018-01-01

In this overview, we summarize the findings of the literature with regards to physiology and pathophysiology of ultra-marathon running. The number of ultra-marathon races and the number of official finishers considerably increased in the last decades especially due to the increased number of female and age-group runners. A typical ultra-marathoner is male, married, well-educated, and ~45 years old. Female ultra-marathoners account for ~20% of the total number of finishers. Ultra-marathoners are older and have a larger weekly training volume, but run more slowly during training compared to marathoners. Previous experience (e.g., number of finishes in ultra-marathon races and personal best marathon time) is the most important predictor variable for a successful ultra-marathon performance followed by specific anthropometric (e.g., low body mass index, BMI, and low body fat) and training (e.g., high volume and running speed during training) characteristics. Women are slower than men, but the sex difference in performance decreased in recent years to ~10–20% depending upon the length of the ultra-marathon. The fastest ultra-marathon race times are generally achieved at the age of 35–45 years or older for both women and men, and the age of peak performance increases with increasing race distance or duration. An ultra-marathon leads to an energy deficit resulting in a reduction of both body fat and skeletal muscle mass. An ultra-marathon in combination with other risk factors, such as extreme weather conditions (either heat or cold) or the country where the race is held, can lead to exercise-associated hyponatremia. An ultra-marathon can also lead to changes in biomarkers indicating a pathological process in specific organs or organ systems such as skeletal muscles, heart, liver, kidney, immune and endocrine system. These changes are usually temporary, depending on intensity and duration of the performance, and usually normalize after the race. In longer ultra

Physiology and Pathophysiology in Ultra-Marathon Running.

PubMed

Knechtle, Beat; Nikolaidis, Pantelis T

2018-01-01

In this overview, we summarize the findings of the literature with regards to physiology and pathophysiology of ultra-marathon running. The number of ultra-marathon races and the number of official finishers considerably increased in the last decades especially due to the increased number of female and age-group runners. A typical ultra-marathoner is male, married, well-educated, and ~45 years old. Female ultra-marathoners account for ~20% of the total number of finishers. Ultra-marathoners are older and have a larger weekly training volume, but run more slowly during training compared to marathoners. Previous experience (e.g., number of finishes in ultra-marathon races and personal best marathon time) is the most important predictor variable for a successful ultra-marathon performance followed by specific anthropometric (e.g., low body mass index, BMI, and low body fat) and training (e.g., high volume and running speed during training) characteristics. Women are slower than men, but the sex difference in performance decreased in recent years to ~10-20% depending upon the length of the ultra-marathon. The fastest ultra-marathon race times are generally achieved at the age of 35-45 years or older for both women and men, and the age of peak performance increases with increasing race distance or duration. An ultra-marathon leads to an energy deficit resulting in a reduction of both body fat and skeletal muscle mass. An ultra-marathon in combination with other risk factors, such as extreme weather conditions (either heat or cold) or the country where the race is held, can lead to exercise-associated hyponatremia. An ultra-marathon can also lead to changes in biomarkers indicating a pathological process in specific organs or organ systems such as skeletal muscles, heart, liver, kidney, immune and endocrine system. These changes are usually temporary, depending on intensity and duration of the performance, and usually normalize after the race. In longer ultra

Improving multi-GNSS ultra-rapid orbit determination for real-time precise point positioning

NASA Astrophysics Data System (ADS)

Li, Xingxing; Chen, Xinghan; Ge, Maorong; Schuh, Harald

2018-03-01

Currently, with the rapid development of multi-constellation Global Navigation Satellite Systems (GNSS), the real-time positioning and navigation are undergoing dramatic changes with potential for a better performance. To provide more precise and reliable ultra-rapid orbits is critical for multi-GNSS real-time positioning, especially for the three merging constellations Beidou, Galileo and QZSS which are still under construction. In this contribution, we present a five-system precise orbit determination (POD) strategy to fully exploit the GPS + GLONASS + BDS + Galileo + QZSS observations from CDDIS + IGN + BKG archives for the realization of hourly five-constellation ultra-rapid orbit update. After adopting the optimized 2-day POD solution (updated every hour), the predicted orbit accuracy can be obviously improved for all the five satellite systems in comparison to the conventional 1-day POD solution (updated every 3 h). The orbit accuracy for the BDS IGSO satellites can be improved by about 80, 45 and 50% in the radial, cross and along directions, respectively, while the corresponding accuracy improvement for the BDS MEO satellites reaches about 50, 20 and 50% in the three directions, respectively. Furthermore, the multi-GNSS real-time precise point positioning (PPP) ambiguity resolution has been performed by using the improved precise satellite orbits. Numerous results indicate that combined GPS + BDS + GLONASS + Galileo (GCRE) kinematic PPP ambiguity resolution (AR) solutions can achieve the shortest time to first fix (TTFF) and highest positioning accuracy in all coordinate components. With the addition of the BDS, GLONASS and Galileo observations to the GPS-only processing, the GCRE PPP AR solution achieves the shortest average TTFF of 11 min with 7{°} cutoff elevation, while the TTFF of GPS-only, GR, GE and GC PPP AR solution is 28, 15, 20 and 17 min, respectively. As the cutoff elevation increases, the reliability and accuracy of GPS-only PPP AR solutions

Electro-rheological finishing for optical surfaces

NASA Astrophysics Data System (ADS)

Cheng, Haobo; Wang, Peng

2009-05-01

Many polishing techniques such as fixed-abrasive polishing, abrasive-free polishing and magnetorheological finishing etc., have been developed. Meanwhile, a new technique is proposed using the mixture of the electro-rheological (Er) fluid with abrasives as polishing slurry, which is a special process does not require pad. Electrorheological fluid is a special suspension liquid, whose viscosity has an approximate proportional relation with the electric strength applied. When the field strength reaches a certain limit, the phase transition occurs and the liquid acquires a solid like character, and while the electric field is removed, the fluid regains its original viscosity during the order of milliseconds. In this research work, we employed the characteristics of viscosity change of Er fluid to hold the polishing particles for micromachining. A point-contact electro-rheological finishing (Erf) tool was designed with a tip diameter 0.5~1mm. Both the anode and the cathode of the electric field were combined in the tool. The electric field could be controllable. When the tool moves across the profile of the work piece, by controlling the electric field strength as well as the other manufacturing parameters we can assure the deterministic material removal. Furthermore, the electro-rheological finishing process has been planned in detailed.

Mach 6 electroformed nickel nozzle refurbishment: FNAS investigation of ultra-smooth surfaces

NASA Technical Reports Server (NTRS)

Rood, Robert; Griffith, Charles; Engelhaupt, Darell; Cernosek, John

1992-01-01

The task objective has been to apply a coating of nickel-phosphorous alloy to a laminar flow wind tunnel nozzle by catalytic deposition and then polish and inspect the inside surface using optical device processes. The surface of the nozzle was coated with a nickel-phosphorous alloy of sufficient hardness and corrosion resistance to improve the durability. Due to plating defects that were clearly process related and not inherent, the final polished part was less than the desired quality. Surface finishing processes and lapping media were identified which produced a submicron surface finish on the interior plated surface. Defects apparently manifested by the first plating attempt were repaired using a small brush plating process demonstrating that individual small defects can be repaired. Measurement and analysis by profilometry demonstrated that quantitative control of the surface can be achieved.

Improvement of magnetorheological finishing surface quality by nanoparticle jet polishing

NASA Astrophysics Data System (ADS)

Peng, Wenqiang; Li, Shengyi; Guan, Chaoliang; Shen, Xinmin; Dai, Yifan; Wang, Zhuo

2013-04-01

Nanoparticle jet polishing (NJP) is presented as a posttreatment to remove magnetorheological finishing (MRF) marks. In the NJP process the material is removed by chemical impact reaction, and the material removal rate of convex part is larger than that of the concave part. Smoothing thus can progress automatically in the NJP process. In the experiment, a silica glass sample polished by MRF was polished by NJP. Experiment results showed the MRF marks were removed clearly. The uniform polishing process shows that the NJP process can remove the MRF marks without destroying the original surface figure. The surface root-mean-square roughness is improved from 0.72 to 0.41 nm. power spectral density analysis indicates the surface quality is improved, and the experimental result validates effective removal of MRF marks by NJP.

SURFACE FINISHES ON STAINLESS STEEL REDUCE BACTERIAL ATTACHMENT AND EARLY BIOFILM FORMATION: SCANNING ELECTRON AND ATOMIC FORCE MICROSCOPY STUDY

EPA Science Inventory

Three common finishing treatments of stainless steel that are used for equipment during poultry processing were tested for resistance to bacterial contamination. Methods were developed to measure attached bacteria and to identify factors that make surface finishes susceptible or ...

Method for forming precision clockplate with pivot pins

DOEpatents

Wild, Ronald L [Albuquerque, NM

2010-06-01

Methods are disclosed for producing a precision clockplate with rotational bearing surfaces (e.g. pivot pins). The methods comprise providing an electrically conductive blank, conventionally machining oversize features comprising bearing surfaces into the blank, optionally machining of a relief on non-bearing surfaces, providing wire accesses adjacent to bearing surfaces, threading the wire of an electrical discharge machine through the accesses and finishing the bearing surfaces by wire electrical discharge machining. The methods have been shown to produce bearing surfaces of comparable dimension and tolerances as those produced by micro-machining methods such as LIGA, at reduced cost and complexity.

Effect of Epoxy on Mechanical Property of SAC305 Solder Joint with Various Surface Finishes Under 3-Point Bend Test.

PubMed

Jeong, Haksan; Myung, Woo-Ram; Sung, Yong-Gue; Kim, Kyung-Yeol; Jung, Seung-Boo

2018-09-01

Microstructures and mechanical property of Sn-3.0Ag-0.5Cu (SAC305) and epoxy Sn-3.0Ag-0.5Cu (epoxy SAC) solder joints were investigated with various surface finishes; organic solderability preservative (OSP), electroless nickel immersion gold (ENIG) and electroless nickel electroless palladium immersion gold (ENEPIG). Bending property of solder joints was evaluated by 3-point bend test method. Microstructure and chemical composition of solder joints was characterized by scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDX), respectively. Epoxy did not effect on intermetallic compound (IMC) morphology. Scalloped shaped Cu6Sn5 IMC was observed at OSP surface finish. Chunky-like shaped and needle-like shaped (Ni,Cu)6Sn5 IMC were observed at the solder/ENIG joint and solder/ENEPIG joint, respectively. The bending cycles of SAC305/OSP joint, SAC305/ENIG joints and SAC305/ENEPIG joints were 720, 440 and 481 cycle numbers. The bending cycles of epoxy SAC and three types surface finished solder joints were over 1000 bending cycles. Under OSP surface finish, bending cycles of epoxy SAC solder was approximately 1.5 times higher than those of SAC305 solder joint. Bending cycles of epoxy SAC solder was over twice times higher than those of SAC305 solder with ENIG and ENEPIG surface finishes. The bending property of epoxy solder joint was enhanced due to epoxy fillet held the solder joint.

Effect of processing parameters on surface finish for fused deposition machinable wax patterns

NASA Technical Reports Server (NTRS)

Roberts, F. E., III

1995-01-01

This report presents a study on the effect of material processing parameters used in layer-by-layer material construction on the surface finish of a model to be used as an investment casting pattern. The data presented relate specifically to fused deposition modeling using a machinable wax.

Practical controller design for ultra-precision positioning of stages with a pneumatic artificial muscle actuator

NASA Astrophysics Data System (ADS)

Tang, T. F.; Chong, S. H.

2017-06-01

This paper presents a practical controller design method for ultra-precision positioning of pneumatic artificial muscle actuator stages. Pneumatic artificial muscle (PAM) actuators are safe to use and have numerous advantages which have brought these actuators to wide applications. However, PAM exhibits strong non-linear characteristics, and these limitations lead to low controllability and limit its application. In practice, the non-linear characteristics of PAM mechanism are difficult to be precisely modeled, and time consuming to model them accurately. The purpose of the present study is to clarify a practical controller design method that emphasizes a simple design procedure that does not acquire plants parameters modeling, and yet is able to demonstrate ultra-precision positioning performance for a PAM driven stage. The practical control approach adopts continuous motion nominal characteristic trajectory following (CM NCTF) control as the feedback controller. The constructed PAM driven stage is in low damping characteristic and causes severe residual vibration that deteriorates motion accuracy of the system. Therefore, the idea to increase the damping characteristic by having an acceleration feedback compensation to the plant has been proposed. The effectiveness of the proposed controller was verified experimentally and compared with a classical PI controller in point-to-point motion. The experiment results proved that the CM NCTF controller demonstrates better positioning performance in smaller motion error than the PI controller. Overall, the CM NCTF controller has successfully to reduce motion error to 3µm, which is 88.7% smaller than the PI controller.

Diamond tool wear detection method using cutting force and its power spectrum analysis in ultra-precision fly cutting

NASA Astrophysics Data System (ADS)

Zhang, G. Q.; To, S.

2014-08-01

Cutting force and its power spectrum analysis was thought to be an effective method monitoring tool wear in many cutting processes and a significant body of research has been conducted on this research area. However, relative little similar research was found in ultra-precision fly cutting. In this paper, a group of experiments were carried out to investigate the cutting forces and its power spectrum characteristics under different tool wear stages. Result reveals that the cutting force increases with the progress of tool wear. The cutting force signals under different tool wear stages were analyzed using power spectrum analysis. The analysis indicates that a characteristic frequency does exist in the power spectrum of the cutting force, whose power spectral density increases with the increasing of tool wear level, this characteristic frequency could be adopted to monitor diamond tool wear in ultra-precision fly cutting.

Surface integrity and corrosion performance of biomedical magnesium-calcium alloy processed by hybrid dry cutting-finish burnishing.

PubMed

Salahshoor, M; Li, C; Liu, Z Y; Fang, X Y; Guo, Y B

2018-02-01

Biodegradable magnesium-calcium (MgCa) alloy is a very attractive orthopedic biomaterial compared to permanent metallic alloys. However, the critical issue is that MgCa alloy corrodes too fast in the human organism. Compared to dry cutting, the synergistic dry cutting-finish burnishing can significantly improve corrosion performance of MgCa0.8 (wt%) alloy by producing a superior surface integrity including good surface finish, high compressive hook-shaped residual stress profile, extended strain hardening in subsurface, and little change of grain size. A FEA model was developed to understand the plastic deformation of MgCa materials during burnishing process. The measured polarization curves, surface micrographs, and element distributions of the corroded surfaces by burnishing show an increasing and uniform corrosion resistance to simulated body fluid. Copyright © 2017 Elsevier Ltd. All rights reserved.

Finishability of CCA pressure-treated wood

Treesearch

Alan Ross; Richard Carlson; William Feist; Steven Bussjaeger

2000-01-01

Thus, a need arose for the development of surface finishes for CCA-treated wood that could address the special requirements of this substrate and provide protection against the ravages of water, sunlight, mildew, and other aspects of weathering and wear. Initially, this need was not addressed, most wood preserving companies had little expertise in surface finishes and...

POLLUTION PREVENTION IN THE METAL FINISHING INDUSTRY

EPA Science Inventory

A broad overview of the metal finishing processes in pollution prevention. The volume of hazardous/toxic waste streams produced from metal finishing operations is significant. It is common for product surfaces to undergo more than 10 finishing steps. The elimination of any of ...

Ultra-wideband surface plasmonic Y-splitter.

PubMed

Gao, Xi; Zhou, Liang; Yu, Xing Yang; Cao, Wei Ping; Li, Hai Ou; Ma, Hui Feng; Cui, Tie Jun

2015-09-07

We present an ultra-wideband Y-splitter based on planar THz plasmonic metamaterials, which consists of a straight waveguide with composite H-shaped structure and two branch waveguides with H-shaped structure. The spoof surface plasmonic polaritons (SSPPs) supported by the straight waveguide occupy the similar dispersion relation and mode characteristic to the ones confined by the branch waveguides. Attributing to these features, the two branch waveguides can equally separate the SSPPs wave propagating along the straight plasmonic waveguide to form a 3dB power divider in an ultra-wideband frequency range. To verify the functionality and performance of the proposed Y-splitter, we scaled down the working frequency to microwave and implemented microwave experiments. The tested device performances have clearly validated the functionality of our designs. It is believed to be applicable for future plasmonic circuit in microwave and THz ranges.

Plasma nanotexturing of silicon surfaces for photovoltaics applications: influence of initial surface finish on the evolution of topographical and optical properties

PubMed Central

FISCHER, GUILLAUME; DRAHI, ETIENNE; FOLDYNA, MARTIN; GERMER, THOMAS A.; JOHNSON, ERIK V.

2018-01-01

Using a plasma to generate a surface texture with feature sizes on the order of tens to hundreds of nanometers (“nanotexturing”) is a promising technique being considered to improve efficiency in thin, high-efficiency crystalline silicon solar cells. This study investigates the evolution of the optical properties of silicon samples with various initial surface finishes (from mirror polish to various states of micron-scale roughness) during a plasma nanotexturing process. It is shown that during said process, the appearance and growth of nanocone-like structures are essentially independent of the initial surface finish, as quantified by the auto-correlation function of the surface morphology. During the first stage of the process (2 min to 15 min etching), the reflectance and light-trapping abilities of the nanotextured surfaces are strongly influenced by the initial surface roughness; however, the differences tend to diminish as the nanostructures become larger. For the longest etching times (15 min or more), the effective reflectance is less than 5 % and a strong anisotropic scattering behavior is also observed for all samples, leading to very elevated levels of light-trapping. PMID:29220984

Mirror-finished superhydrophobic aluminum surfaces modified by anodic alumina nanofibers and self-assembled monolayers

NASA Astrophysics Data System (ADS)

Nakajima, Daiki; Kikuchi, Tatsuya; Natsui, Shungo; Suzuki, Ryosuke O.

2018-05-01

We demonstrate mirror-finished superhydrophobic aluminum surfaces fabricated via the formation of anodic alumina nanofibers and subsequent modification with self-assembled monolayers (SAMs). High-density anodic alumina nanofibers were formed on the aluminum surface via anodizing in a pyrophosphoric acid solution. The alumina nanofibers became tangled and bundled by further anodizing at low temperature because of their own weight, and the aluminum surface was completely covered by the long falling nanofibers. The nanofiber-covered aluminum surface exhibited superhydrophilic behavior, with a contact angle measuring less than 10°. As the nanofiber-covered aluminum surface was modified with n-alkylphosphonic acid SAMs, the water contact angle drastically shifted to superhydrophobicity, measuring more than 150°. The contact angle increased with the applied voltage during pyrophosphoric acid anodizing, the anodizing time, and the number of carbon atoms contained in the SAM molecules modified on the alumina nanofibers. By optimizing the anodizing and SAM-modification conditions, superhydrophobic behavior could be achieved with only a brief pyrophosphoric acid anodizing period of 3 min and subsequent simple immersion in SAM solutions. The superhydrophobic aluminum surface exhibited a high reflectance, measuring approximately 99% across most of the visible spectrum, similar to that of an electropolished aluminum surface. Therefore, our mirror-finished superhydrophobic aluminum surface based on anodic alumina nanofibers and SAMs can be used as a reflective mirror in various optical applications such as concentrated solar power systems.

Dynamics of Wetting of Ultra Hydrophobic Surfaces

NASA Astrophysics Data System (ADS)

Mohammad Karim, Alireza; Kim, Jeong-Hyun; Rothstein, Jonathan; Kavehpour, Pirouz; Mechanical and Industrial Engineering, University of Massachusetts, Amherst Collaboration

2013-11-01

Controlling the surface wettability of hydrophobic and super hydrophobic surfaces has extensive industrial applications ranging from coating, painting and printing technology and waterproof clothing to efficiency increase in power and water plants. This requires enhancing the knowledge about the dynamics of wetting on these hydrophobic surfaces. We have done experimental investigation on the dynamics of wetting on hydrophobic surfaces by looking deeply in to the dependency of the dynamic contact angles both advancing and receding on the velocity of the three-phase boundary (Solid/Liquid/Gas interface) using the Wilhelmy plate method with different ultra-hydrophobic surfaces. Several fluids with different surface tension and viscosity are used to study the effect of physical properties of liquids on the governing laws.

Rhabdomyolysis and exercise-associated hyponatremia in ultra-bikers and ultra-runners.

PubMed

Chlíbková, Daniela; Knechtle, Beat; Rosemann, Thomas; Tomášková, Ivana; Novotný, Jan; Žákovská, Alena; Uher, Tomáš

2015-01-01

Exercise-associated hyponatremia (EAH), rhabdomyolysis and renal failure appear to be a unique problem in ultra-endurance racers. We investigated the combined occurrence of EAH and rhabdomyolysis in seven different ultra-endurance races and disciplines (i.e. multi-stage mountain biking, 24-h mountain biking, 24-h ultra-running and 100-km ultra-running). Two (15.4%) ultra-runners (man and woman) from hyponatremic ultra-athletes (n = 13) and four (4%) ultra-runners (four men) from the normonatremic group (n = 100) showed rhabdomyolysis following elevated blood creatine kinase (CK) levels > 10,000 U/L without the development of renal failure and the necessity of a medical treatment. Post-race creatine kinase, plasma and urine creatinine significantly increased, while plasma [Na(+)] and creatine clearance decreased in hyponatremic and normonatremic athletes, respectively. The percentage increase of CK was higher in the hyponatremic compared to the normonatremic group (P < 0.05). Post-race CK levels were higher in ultra-runners compared to mountain bikers (P < 0.01), in faster normonatremic (P < 0.05) and older and more experienced hyponatremic ultra-athletes (P < 0.05). In all finishers, pre-race plasma [K(+)] was related to post-race CK (P < 0.05). Hyponatremic ultra-athletes tended to develop exercise-induced rhabdomyolysis more frequently than normonatremic ultra-athletes. Ultra-runners tended to develop rhabdomyolysis more frequently than mountain bikers. We found no association between post-race plasma [Na(+)] and CK concentration in both hypo- and normonatremic ultra-athletes.

Additive manufacturing of reflective optics: evaluating finishing methods

NASA Astrophysics Data System (ADS)

Leuteritz, G.; Lachmayer, R.

2018-02-01

Individually shaped light distributions become more and more important in lighting technologies and thus the importance of additively manufactured reflectors increases significantly. The vast field of applications ranges from automotive lighting to medical imaging and bolsters the statement. However, the surfaces of additively manufactured reflectors suffer from insufficient optical properties even when manufactured using optimized process parameters for the Selective Laser Melting (SLM) process. Therefore post-process treatments of reflectors are necessary in order to further enhance their optical quality. This work concentrates on the effectiveness of post-process procedures for reflective optics. Based on already optimized aluminum reflectors, which are manufactured with a SLM machine, the parts are differently machined after the SLM process. Selected finishing methods like laser polishing, sputtering or sand blasting are applied and their effects quantified and compared. The post-process procedures are investigated on their impact on surface roughness and reflectance as well as geometrical precision. For each finishing method a demonstrator will be created and compared to a fully milled sample and among themselves. Ultimately, guidelines are developed in order to figure out the optimal treatment of additively manufactured reflectors regarding their optical and geometrical properties. Simulations of the light distributions will be validated with the developed demonstrators.

Effect of overglazed and polished surface finishes on the compressive fracture strength of machinable ceramic materials.

PubMed

Asai, Tetsuya; Kazama, Ryunosuke; Fukushima, Masayoshi; Okiji, Takashi

2010-11-01

Controversy prevails over the effect of overglazing on the fracture strength of ceramic materials. Therefore, the effects of different surface finishes on the compressive fracture strength of machinable ceramic materials were investigated in this study. Plates prepared from four commercial brands of ceramic materials were either surface-polished or overglazed (n=10 per ceramic material for each surface finish), and bonded to flat surfaces of human dentin using a resin cement. Loads at failure were determined and statistically analyzed using two-way ANOVA and Bonferroni test. Although no statistical differences in load value were detected between polished and overglazed groups (p>0.05), the fracture load of Vita Mark II was significantly lower than those of ProCAD and IPS Empress CAD, whereas that of IPS e.max CAD was significantly higher than the latter two ceramic materials (p<0.05). It was concluded that overglazed and polished surfaces produced similar compressive fracture strengths irrespective of the machinable ceramic material tested, and that fracture strength was material-dependent.

Ultra-fast boriding of metal surfaces for improved properties

DOEpatents

Timur, Servet; Kartal, Guldem; Eryilmaz, Osman L.; Erdemir, Ali

2015-02-10

A method of ultra-fast boriding of a metal surface. The method includes the step of providing a metal component, providing a molten electrolyte having boron components therein, providing an electrochemical boriding system including an induction furnace, operating the induction furnace to establish a high temperature for the molten electrolyte, and boriding the metal surface to achieve a boride layer on the metal surface.

Method and system for ultra-precision positioning

DOEpatents

Montesanti, Richard C.; Locke, Stanley F.; Thompson, Samuel L.

2005-01-11

An apparatus and method is disclosed for ultra-precision positioning. A slide base provides a foundational support. A slide plate moves with respect to the slide base along a first geometric axis. Either a ball-screw or a piezoelectric actuator working separate or in conjunction displaces the slide plate with respect to the slide base along the first geometric axis. A linking device directs a primary force vector into a center-line of the ball-screw. The linking device consists of a first link which directs a first portion of the primary force vector to an apex point, located along the center-line of the ball-screw, and a second link for directing a second portion of the primary force vector to the apex point. A set of rails, oriented substantially parallel to the center-line of the ball-screw, direct movement of the slide plate with respect to the slide base along the first geometric axis and are positioned such that the apex point falls within a geometric plane formed by the rails. The slide base, the slide plate, the ball-screw, and the linking device together form a slide assembly. Multiple slide assemblies can be distributed about a platform. In such a configuration, the platform may be raised and lowered, or tipped and tilted by jointly or independently displacing the slide plates.

New vibration-assisted magnetic abrasive polishing (VAMAP) method for microstructured surface finishing.

PubMed

Guo, Jiang; Kum, Chun Wai; Au, Ka Hing; Tan, Zhi'En Eddie; Wu, Hu; Liu, Kui

2016-06-13

In order to polish microstructured surface without deteriorating its profile, we propose a new vibration-assisted magnetic abrasive polishing (VAMAP) method. In this method, magnetic force guarantees that the magnetic abrasives can well contact the microstructured surface and access the corners of microstructures while vibration produces a relative movement between microstructures and magnetic abrasives. As the vibration direction is parallel to the microstructures, the profile of the microstructures will not be deteriorated. The relation between vibration and magnetic force was analyzed and the feasibility of this method was experimentally verified. The results show that after polishing, the surface finish around microstructures was significantly improved while the profile of microstructures was well maintained.

Fabrication of micro-lens array on convex surface by meaning of micro-milling

NASA Astrophysics Data System (ADS)

Zhang, Peng; Du, Yunlong; Wang, Bo; Shan, Debin

2014-08-01

In order to develop the application of the micro-milling technology, and to fabricate ultra-precision optical surface with complex microstructure, in this paper, the primary experimental research on micro-milling complex microstructure array is carried out. A complex microstructure array surface with vary parameters is designed, and the mathematic model of the surface is set up and simulated. For the fabrication of the designed microstructure array surface, a micro three-axis ultra-precision milling machine tool is developed, aerostatic guideway drove directly by linear motor is adopted in order to guarantee the enough stiffness of the machine, and novel numerical control strategy with linear encoders of 5nm resolution used as the feedback of the control system is employed to ensure the extremely high motion control accuracy. With the help of CAD/CAM technology, convex micro lens array on convex spherical surface with different scales on material of polyvinyl chloride (PVC) and pure copper is fabricated using micro tungsten carbide ball end milling tool based on the ultra-precision micro-milling machine. Excellent nanometer-level micro-movement performance of the axis is proved by motion control experiment. The fabrication is nearly as the same as the design, the characteristic scale of the microstructure is less than 200μm and the accuracy is better than 1μm. It prove that ultra-precision micro-milling technology based on micro ultra-precision machine tool is a suitable and optional method for micro manufacture of microstructure array surface on different kinds of materials, and with the development of micro milling cutter, ultraprecision micro-milling complex microstructure surface will be achieved in future.

Precision ablation of dental enamel using a subpicosecond pulsed laser.

PubMed

Rode, A V; Gamaly, E G; Luther-Davies, B; Taylor, B T; Graessel, M; Dawes, J M; Chan, A; Lowe, R M; Hannaford, P

2003-12-01

In this study we report the use of ultra-short-pulsed near-infrared lasers for precision laser ablation of freshly extracted human teeth. The laser wavelength was approximately 800nm, with pulsewidths of 95 and 150fs, and pulse repetition rates of 1kHz. The laser beam was focused to an approximate diameter of 50microm and was scanned over the tooth surface. The rise in the intrapulpal temperature was monitored by embedded thermocouples, and was shown to remain below 5 degrees C when the tooth was air-cooled during laser treatment. The surface preparation of the ablated teeth, observed by optical and electron microscopy, showed no apparent cracking or heat effects, and the hardness and Raman spectra of the laser-treated enamel were not distinguishable from those of native enamel. This study indicates the potential for ultra-short-pulsed lasers to effect precision ablation of dental enamel.

Effect of different surface finishing/polishing procedures on color stability of esthetic restorative materials: A spectrophotometric evaluation

PubMed Central

Beltrami, Riccardo; Ceci, Matteo; De Pani, Gabriele; Vialba, Lodovico; Federico, Ricaldone; Poggio, Claudio; Colombo, Marco

2018-01-01

Objective: To evaluate the color stability of different esthetic restorative materials after surface finishing/polishing with different procedures. Materials and Methods: All materials were polymerized into silicone rubber rings to obtain specimens identical in size. Samples were randomly assigned into four groups (10 specimens of each composite for each group), and they were finished with different procedures: Control group (Group 1), three or two polishers interspersed with diamond grit (Groups 3 and 2, respectively), and one tungsten carbide bur + one polisher interspersed with diamond grit (Group 4). After staining process in coffee, a colorimetric evaluation according to the CIE L*a*b* system was performed by a blind trained operator at 7, 14, 21, and 28 days. Shapiro–Wilk test and Kruskal–Wallis analysis of variance were applied to assess significant differences among restorative materials. Means of the different polishing/finishing groups were compared with Scheffe's multiple comparison test at the 0.05 level of significance. Results: In control group, significant lower discolorations were recorded for Essentia, Admira Fusion, and Estelite. After finishing, Filtek Supreme XTE and Ceram.X Universal showed a significantly lower degree of staining. The finishing technique used for Group 4 produced higher color changes. Conclusions: Tungsten carbide burs produced the higher color variations; after finishing, the nanofilled composites showed lower discoloration than nanohybrid ones, and the time of exposure to the staining agent and the polishing/finishing technique influenced the color change. PMID:29657525

Effect of surface finish on the failure mechanisms of flip-chip solder joints under electromigration

NASA Astrophysics Data System (ADS)

Lin, Y. L.; Lai, Y. S.; Tsai, C. M.; Kao, C. R.

2006-12-01

Two substrate surface finishes, Au/Ni and organic solderable preservative (OSP), were used to study the effect of the surface finish on the reliability of flip-chip solder joints under electromigration at 150°C ambient temperature. The solder used was eutectic PbSn, and the applied current density was 5×103 A/cm2 at the contact window of the chip. The under bump metallurgy (UBM) on the chip was sputtered Cu/Ni. It was found that the mean-time-to-failure (MTTF) of the OSP joints was six times better than that of the Au/Ni joints (3080 h vs. 500 h). Microstructure examinations uncovered that the combined effect of current crowding and the accompanying local Joule heating accelerated the local Ni UBM consumption near the point of electron entrance. Once Ni was depleted at a certain region, this region became nonconductive, and the flow of the electrons was diverted to the neighboring region. This neighboring region then became the place where electrons entered the joint, and the local Ni UBM consumption was accelerated. This process repeated itself, and the Ni-depleted region extended further on, creating an ever-larger nonconductive region. The solder joint eventually, failed when the nonconductive region became too large, making the effective current density very high. Accordingly, the key factor determining the MTTF was the Ni consumption rate. The joints with the OSP surface finish had a longer MTTF because Cu released from the substrate was able to reduce the Ni consumption rate.

Atomic Step Formation on Sapphire Surface in Ultra-precision Manufacturing

PubMed Central

Wang, Rongrong; Guo, Dan; Xie, Guoxin; Pan, Guoshun

2016-01-01

Surfaces with controlled atomic step structures as substrates are highly relevant to desirable performances of materials grown on them, such as light emitting diode (LED) epitaxial layers, nanotubes and nanoribbons. However, very limited attention has been paid to the step formation in manufacturing process. In the present work, investigations have been conducted into this step formation mechanism on the sapphire c (0001) surface by using both experiments and simulations. The step evolutions at different stages in the polishing process were investigated with atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM). The simulation of idealized steps was constructed theoretically on the basis of experimental results. It was found that (1) the subtle atomic structures (e.g., steps with different sawteeth, as well as steps with straight and zigzag edges), (2) the periodicity and (3) the degree of order of the steps were all dependent on surface composition and miscut direction (step edge direction). A comparison between experimental results and idealized step models of different surface compositions has been made. It has been found that the structure on the polished surface was in accordance with some surface compositions (the model of single-atom steps: Al steps or O steps). PMID:27444267

Atomic Step Formation on Sapphire Surface in Ultra-precision Manufacturing

NASA Astrophysics Data System (ADS)

Wang, Rongrong; Guo, Dan; Xie, Guoxin; Pan, Guoshun

2016-07-01

Surfaces with controlled atomic step structures as substrates are highly relevant to desirable performances of materials grown on them, such as light emitting diode (LED) epitaxial layers, nanotubes and nanoribbons. However, very limited attention has been paid to the step formation in manufacturing process. In the present work, investigations have been conducted into this step formation mechanism on the sapphire c (0001) surface by using both experiments and simulations. The step evolutions at different stages in the polishing process were investigated with atomic force microscopy (AFM) and high resolution transmission electron microscopy (HRTEM). The simulation of idealized steps was constructed theoretically on the basis of experimental results. It was found that (1) the subtle atomic structures (e.g., steps with different sawteeth, as well as steps with straight and zigzag edges), (2) the periodicity and (3) the degree of order of the steps were all dependent on surface composition and miscut direction (step edge direction). A comparison between experimental results and idealized step models of different surface compositions has been made. It has been found that the structure on the polished surface was in accordance with some surface compositions (the model of single-atom steps: Al steps or O steps).

Drywall Finishing Manual.

ERIC Educational Resources Information Center

Lengert, Gerald

This manual, a self-study guide for apprentices in the drywall finishing trade in British Columbia, attempts to establish standards for the trade. It tells how to produce a properly taped and filled drywall surface and describes what that surface should look like. The standards emphasize quality work that can be realistically achieved on the job.…

Contamination control and assay results for the Majorana Demonstrator ultra clean components

NASA Astrophysics Data System (ADS)

Christofferson, C. D.; Abgrall, N.; Alvis, S. I.; Arnquist, I. J.; Avignone, F. T.; Barabash, A. S.; Barton, C. J.; Bertrand, F. E.; Bode, T.; Bradley, A. W.; Brudanin, V.; Busch, M.; Buuck, M.; Caldwell, T. S.; Chan, Y.-D.; Chu, P.-H.; Cuesta, C.; Detwiler, J. A.; Dunagan, C.; Efremenko, Yu.; Ejiri, H.; Elliott, S. R.; Gilliss, T.; Giovanetti, G. K.; Green, M. P.; Gruszko, J.; Guinn, I. S.; Guiseppe, V. E.; Haufe, C. R.; Hehn, L.; Henning, R.; Hoppe, E. W.; Howe, M. A.; Keeter, K. J.; Kidd, M. F.; Konovalov, S. I.; Kouzes, R. T.; Lopez, A. M.; Martin, R. D.; Massarczyk, R.; Meijer, S. J.; Mertens, S.; Myslik, J.; O'Shaughnessy, C.; Othman, G.; Poon, A. W. P.; Radford, D. C.; Rager, J.; Reine, A. L.; Rielage, K.; Robertson, R. G. H.; Rouf, N. W.; Shanks, B.; Shirchenko, M.; Suriano, A. M.; Tedeschi, D.; Trimble, J. E.; Varner, R. L.; Vasilyev, S.; Vetter, K.; Vorren, K.; White, B. R.; Wilkerson, J. F.; Wiseman, C.; Xu, W.; Yakushev, E.; Yu, C.-H.; Yumatov, V.; Zhitnikov, I.; Zhu, B. X.

2018-01-01

The Majorana Demonstrator is a neutrinoless double beta decay experiment utilizing enriched Ge-76 detectors in 2 separate modules inside of a common solid shield at the Sanford Underground Research Facility. The Demonstrator has utilized world leading assay sensitivities to develop clean materials and processes for producing ultra-pure copper and plastic components. This experiment is now operating, and initial data provide new insights into the success of cleaning and processing. Post production copper assays after the completion of Module 1 showed an increase in U and Th contamination in finished parts compared to starting bulk material. A revised cleaning method and additional round of surface contamination studies prior to Module 2 construction have provided evidence that more rigorous process control can reduce surface contamination. This article describes the assay results and discuss further studies to take advantage of assay capabilities for the purpose of maintaining ultra clean fabrication and process design.

Atomically Precise Surface Engineering for Producing Imagers

NASA Technical Reports Server (NTRS)

Nikzad, Shouleh (Inventor); Hoenk, Michael E. (Inventor); Greer, Frank (Inventor); Jones, Todd J. (Inventor)

2015-01-01

High-quality surface coatings, and techniques combining the atomic precision of molecular beam epitaxy and atomic layer deposition, to fabricate such high-quality surface coatings are provided. The coatings made in accordance with the techniques set forth by the invention are shown to be capable of forming silicon CCD detectors that demonstrate world record detector quantum efficiency (>50%) in the near and far ultraviolet (155 nm-300 nm). The surface engineering approaches used demonstrate the robustness of detector performance that is obtained by achieving atomic level precision at all steps in the coating fabrication process. As proof of concept, the characterization, materials, and exemplary devices produced are presented along with a comparison to other approaches.

Evaluation of several finishes on severely weathered wood

Treesearch

R. Sam Williams; Peter Sotos; William Feist

1999-01-01

Alkyd-, oil-modified-latex-, and latex-based finishes were applied to severely weathered western redcedar and redwood boards that did not have any surface treatment to ameliorate the weathered surface prior to painting. Six finishes were evaluated annually for 11 years for cracking, flaking, erosion, mildew growth, discoloration, and general appearance. Low-solids-...

An Ultra-Precise Method for the Nano Thin-Film Removal

NASA Astrophysics Data System (ADS)

Pa, P. S.

In this research an electrode-set is used to investigate via an ultra-precise method for the removal of Indium Tin Oxide (ITO) thin-film microstructure from defective display panels to conquer the low yield rate in display panel production as to from imperfect Indium Tin Oxide layer deposition is well known. This process, which involves the removal of ITO layer substructure by means of an electrochemical removal (ECMR), is of major interest to the optoelectronics semiconductor industry. In this electro machining process a high current flow and high feed rate of the display (color filter) achieves complete and efficient removal of the ITO layer. The ITO thin-film can be removed completely by a proper combination of feed rate and electric power. A small gap between the diameter cathode virtual rotation circle and the diameter virtual rotation circle also corresponds to a higher removal rate. A small anode edge radius with a small cathode edge radius effectively improves dregs discharge and is an advantage when associated with a high workpiece feed rate. This precision method for the recycling of defective display screen color filters is presented as an effective tool for use in the screen manufacturing process. The defective Indium Tin Oxide thin-film can be removed easily and cleanly in a short time. The complete removal of the ITO layer makes it possible to put these panels back into the production line for reuse with a considerable reduction of both waste and production cost.

Fine figure correction and other applications using novel MRF fluid designed for ultra-low roughness

NASA Astrophysics Data System (ADS)

Maloney, Chris; Oswald, Eric S.; Dumas, Paul

2015-10-01

An increasing number of technologies require ultra-low roughness (ULR) surfaces. Magnetorheological Finishing (MRF) is one of the options for meeting the roughness specifications for high-energy laser, EUV and X-ray applications. A novel MRF fluid, called C30, has been developed to finish surfaces to ULR. This novel MRF fluid is able to achieve <1.5Å RMS roughness on fused silica and other materials, but has a lower material removal rate with respect to other MRF fluids. As a result of these properties, C30 can also be used for applications in addition to finishing ULR surfaces. These applications include fine figure correction, figure correcting extremely soft materials and removing cosmetic defects. The effectiveness of these new applications is explored through experimental data. The low removal rate of C30 gives MRF the capability to fine figure correct low amplitude errors that are usually difficult to correct with higher removal rate fluids. The ability to figure correct extremely soft materials opens up MRF to a new realm of materials that are difficult to polish. C30 also offers the ability to remove cosmetic defects that often lead to failure during visual quality inspections. These new applications for C30 expand the niche in which MRF is typically used for.

CAPSULE REPORT - MANAGING CYANIDE IN METAL FINISHING

EPA Science Inventory

The purpose of this document is to provide guidance to surface finishing manufacturers, metal finishing decision maker and regulators on management practices and control technologies for managing cyanide in the workplace. This information can benefit key industry stakeholder gro...

Application and testing of additive manufacturing for mirrors and precision structures

NASA Astrophysics Data System (ADS)

Sweeney, Michael; Acreman, Martyn; Vettese, Tom; Myatt, Ray; Thompson, Mike

2015-09-01

Additive Manufacturing (aka AM, and 3-D printing) is widely touted in the media as the foundation for the next industrial revolution. Beneath the hype, AM does indeed offer profound advantages in lead-time, dramatically reduced consumption of expensive raw materials, while enabling new and innovative design forms that cannot be produced by other means. General Dynamics and their industry partners have begun to embrace this technology for mirrors and precision structures used in the aerospace, defense, and precision optical instrumentation industries. Aggressively lightweighted, open and closed back test mirror designs, 75-150 mm in size, were first produced by AM from several different materials. Subsequent optical finishing and test experiments have exceeded expectations for density, surface finish, dimensional stability and isotropy of thermal expansion on the optical scale of measurement. Materials currently under examination include aluminum, titanium, beryllium, aluminum beryllium, Inconel 625, stainless steel/bronze, and PEKK polymer.

Simulation of Magnetic Field Assisted Finishing (MFAF) Process Utilizing Smart MR Polishing Tool

NASA Astrophysics Data System (ADS)

Barman, Anwesa; Das, Manas

2017-02-01

Magnetic field assisted finishing process is an advanced finishing process. This process is capable of producing nanometer level surface finish. In this process magnetic field is applied to control the finishing forces using magnetorheological polishing medium. In the current study, permanent magnet is used to provide the required magnetic field in the finishing zone. The working gap between the workpiece and the magnet is filled with MR fluid which is used as the polishing brush to remove surface undulations from the top surface of the workpiece. In this paper, the distribution of magnetic flux density on the workpiece surface and behaviour of MR polishing medium during finishing are analyzed using commercial finite element packages (Ansys Maxwell® and Comsol®). The role of magnetic force in the indentation of abrasive particles on the workpiece surface is studied. A two-dimensional simulation study of the steady, laminar, and incompressible MR fluid flow behaviour during finishing process is carried out. The material removal and surface roughness modelling of the finishing process are also presented. The indentation force by a single active abrasive particle on the workpiece surface is modelled during simulation. The velocity profile of MR fluid with and without application of magnetic field is plotted. It shows non-Newtonian property without application of magnetic field. After that the total material displacement due to one abrasive particle is plotted. The simulated roughness profile is in a good agreement with the experimental results. The conducted study will help in understanding the fluid behavior and the mechanism of finishing during finishing process. Also, the modelling and simulation of the process will help in achieving better finishing performance.

Laser damage initiation and growth of antireflection coated S-FAP crystal surfaces prepared by pitch lap and magnetorheological finishing

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

Stolz, C J; Menapace, J A; Schaffers, K I

Antireflection (AR) coatings typically damage at the interface between the substrate and coating. Therefore the substrate finishing technology can have an impact on the laser resistance of the coating. For this study, AR coatings were deposited on Yb:S-FAP [Yb{sup 3+}:Sr{sub 5}(PO{sub 4}){sub 3}F] crystals that received a final polish by both conventional pitch lap finishing as well as magnetorheological finishing (MRF). SEM images of the damage morphology reveals laser damage originates at scratches and at substrate coating interfacial absorbing defects. Previous damage stability tests on multilayer mirror coatings and bare surfaces revealed damage growth can occur at fluences below themore » initiation fluence. The results from this study suggest the opposite trend for AR coatings. Investigation of unstable HR and uncoated surface damage morphologies reveals significant radial cracking that is not apparent with AR damage due to AR delamination from the coated surface with few apparent cracks at the damage boundary. Damage stability tests show that coated Yb:S-FAP crystals can operate at 1057 nm at fluences around 20 J/cm{sup 2} at 10 ns; almost twice the initiation damage threshold.« less

Effect of finishing and polishing procedures on surface roughness, gloss and color of resin-based composites.

PubMed

Paravina, Rade D; Roeder, Leslie; Lu, Huan; Vogel, Karin; Powers, John M

2004-08-01

To evaluate the effects of different finishing and polishing procedures on surface roughness, gloss and color of five resin composites: two experimental microhybrid composites - FZ-Dentin (FZD) and FZ-Enamel (FZE), one commercial microhybrid composite - Esthet-X (EX), and two microfilled composites - Heliomolar (HM) and Renamel Microfill (RM). Surface roughness, gloss and color of the disc-shaped specimens (10 mm in diameter and 2-mm thick) were measured as Mylar (baseline), 16-fluted carbide bur and polishing were completed. Sixteen specimens of each composite were randomized to four groups of four. After finishing with a 16-fluted finishing bur, each group was polished by a different system: 1. Astropol (A), 2. Sof-lex disc (S), 3. Po-Go (P), 4. Enhance (E). Average surface roughness (Ra) was measured with a profilometer. Gloss measurements were performed using small-area glossmeter, while color coordinate values were recorded using a spectrophotometer. A deltaE*ab< or =1 was considered to be the limit of perceptibility. The order of surface roughness ranked according to polishing system (for all five composites together) was: P < S < E < A. The order of surface roughness ranked according to composites was: RM < FZD < FZ < HM < EX. The order of gloss ranked according to polishing system (for all five composites together) was: P > E > A > S. The order of gloss values for the polished composites (for each of four polishing systems) was: RM > FZD > FZE > HM > EX. Fisher's PLSD intervals at the 0.05 level of significance for comparisons of means of surface roughness among five composites and four polishing systems were 0.01 and 0.01 microm, respectively. Fisher's PLSD intervals at the 0.05 level of significance for comparisons of means of gloss among five composites and four polishing systems were 6 and 5 GU, respectively. Color differences (deltaE*ab) among five composites and four polishing methods were found to range from 0.2 to 1.1.

Progressive Precision Surface Design

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

Duchaineau, M; Joy, KJ

2002-01-11

We introduce a novel wavelet decomposition algorithm that makes a number of powerful new surface design operations practical. Wavelets, and hierarchical representations generally, have held promise to facilitate a variety of design tasks in a unified way by approximating results very precisely, thus avoiding a proliferation of undergirding mathematical representations. However, traditional wavelet decomposition is defined from fine to coarse resolution, thus limiting its efficiency for highly precise surface manipulation when attempting to create new non-local editing methods. Our key contribution is the progressive wavelet decomposition algorithm, a general-purpose coarse-to-fine method for hierarchical fitting, based in this paper on anmore » underlying multiresolution representation called dyadic splines. The algorithm requests input via a generic interval query mechanism, allowing a wide variety of non-local operations to be quickly implemented. The algorithm performs work proportionate to the tiny compressed output size, rather than to some arbitrarily high resolution that would otherwise be required, thus increasing performance by several orders of magnitude. We describe several design operations that are made tractable because of the progressive decomposition. Free-form pasting is a generalization of the traditional control-mesh edit, but for which the shape of the change is completely general and where the shape can be placed using a free-form deformation within the surface domain. Smoothing and roughening operations are enhanced so that an arbitrary loop in the domain specifies the area of effect. Finally, the sculpting effect of moving a tool shape along a path is simulated.« less

Chemical surface deposition of ultra-thin semiconductors

DOEpatents

McCandless, Brian E.; Shafarman, William N.

2003-03-25

A chemical surface deposition process for forming an ultra-thin semiconducting film of Group IIB-VIA compounds onto a substrate. This process eliminates particulates formed by homogeneous reactions in bath, dramatically increases the utilization of Group IIB species, and results in the formation of a dense, adherent film for thin film solar cells. The process involves applying a pre-mixed liquid coating composition containing Group IIB and Group VIA ionic species onto a preheated substrate. Heat from the substrate causes a heterogeneous reaction between the Group IIB and VIA ionic species of the liquid coating composition, thus forming a solid reaction product film on the substrate surface.

Evaluation of the Effect of Surface Finish on High-Cycle Fatigue of SLM-IN718

NASA Technical Reports Server (NTRS)

Lambert, D. M.

2016-01-01

The surface finish of parts produced by additive manufacturing processes is much rougher than the surface finish generated by machining processes, and a rougher surface can reduce the fatigue strength of a part. This paper discusses an effort to quantify that reduction of strength in high-cycle fatigue for selective laser melt (SLM) coupons. A high-cycle fatigue (HCF) knockdown factor was estimated for Inconel 718, manufactured with the SLM process. This factor is the percentage reduction from the maximum stress in fatigue for low-stress ground (LSG) specimens to the maximum stress of those left with the original surface condition at the same fatigue life. Specimens were provided by a number of vendors, free to use their "best practice"; only one heat treat condition was considered; and several test temperatures were characterized, including room temperature, 800F, 1000F, and 1200F. The 1000F data had a large variance, and was omitted from consideration in this document. A first method used linear approximations extracted from the graphs, and only where data was available for both. A recommended knockdown factor of the as-built surface condition (average roughness of approximately 245 micro-inches/inch) versus low-stress ground condition (roughness no more than 4 micro-inches/inch) was established at approximately 1/3 or 33%. This is to say that for the as-built surface condition, a maximum stress of 2/3 of the stress for LSG can be expected to produce a similar life in the as-built surface condition. In this first evaluation, the knockdown factor did not appear to be a function of temperature. A second approach, the "KP method", incorporated the surface finish measure into a new parameter termed the pseudo-stress intensity factor, Kp, which was formulated to be similar to the fracture mechanics stress intensity factor. Using Kp, the variance seemed to be reduced across all sources, and knockdown factors were estimated using Kp over the range where data occurred. A

A 3.9 ps Time-Interval RMS Precision Time-to-Digital Converter Using a Dual-Sampling Method in an UltraScale FPGA

NASA Astrophysics Data System (ADS)

Wang, Yonggang; Liu, Chong

2016-10-01

Field programmable gate arrays (FPGAs) manufactured with more advanced processing technology have faster carry chains and smaller delay elements, which are favorable for the design of tapped delay line (TDL)-style time-to-digital converters (TDCs) in FPGA. However, new challenges are posed in using them to implement TDCs with a high time precision. In this paper, we propose a bin realignment method and a dual-sampling method for TDC implementation in a Xilinx UltraScale FPGA. The former realigns the disordered time delay taps so that the TDC precision can approach the limit of its delay granularity, while the latter doubles the number of taps in the delay line so that the TDC precision beyond the cell delay limitation can be expected. Two TDC channels were implemented in a Kintex UltraScale FPGA, and the effectiveness of the new methods was evaluated. For fixed time intervals in the range from 0 to 440 ns, the average RMS precision measured by the two TDC channels reaches 5.8 ps using the bin realignment, and it further improves to 3.9 ps by using the dual-sampling method. The time precision has a 5.6% variation in the measured temperature range. Every part of the TDC, including dual-sampling, encoding, and on-line calibration, could run at a 500 MHz clock frequency. The system measurement dead time is only 4 ns.

A Magnetorheological Polishing-Based Approach for Studying Precision Microground Surfaces of Tungsten Materials

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

Shafrir, S.N.; Lambropoulos, J.C.; Jacobs, S.D.

2007-03-23

Surface features of tungsten carbide composites processed by bound abrasive deterministic microgrinding and magnetorheological finishing (MRF) were studied for five WC-Ni composites, including one binderless material. All the materials studied were nonmagnetic with different microstructures and mechanical properties. White-light interferometry, scanning electron microscopy, and atomic force microscopy were used to characterize the surfaces after various grinding steps, surface etching, and MRF spot-taking.

Acidic magnetorheological finishing of infrared polycrystalline materials.

PubMed

Salzman, S; Romanofsky, H J; West, G; Marshall, K L; Jacobs, S D; Lambropoulos, J C

2016-10-20

Chemical-vapor-deposited (CVD) ZnS is an example of a polycrystalline material that is difficult to polish smoothly via the magnetorheological finishing (MRF) technique. When MRF-polished, the internal infrastructure of the material tends to manifest on the surface as millimeter-sized "pebbles," and the surface roughness observed is considerably high. The fluid's parameters important to developing a magnetorheological (MR) fluid that is capable of polishing CVD ZnS smoothly were previously discussed and presented. These parameters were acidic pH (∼4.5) and low viscosity (∼47  cP). MRF with such a unique MR fluid was shown to reduce surface artifacts in the form of pebbles; however, surface microroughness was still relatively high because of the absence of a polishing abrasive in the formulation. In this study, we examine the effect of two polishing abrasives-alumina and nanodiamond-on the surface finish of several CVD ZnS substrates, and on other important IR polycrystalline materials that were finished with acidic MR fluids containing these two polishing abrasives. Surface microroughness results obtained were as low as ∼28  nm peak-to-valley and ∼6-nm root mean square.

Acidic magnetorheological finishing of infrared polycrystalline materials

DOE PAGES

Salzman, S.; Romanofsky, H. J.; West, G.; ...

2016-10-12

Here, chemical-vapor–deposited (CVD) ZnS is an example of a polycrystalline material that is difficult to polish smoothly via the magnetorheological–finishing (MRF) technique. When MRF-polished, the internal infrastructure of the material tends to manifest on the surface as millimeter-sized “pebbles,” and the surface roughness observed is considerably high. The fluid’s parameters important to developing a magnetorheological (MR) fluid that is capable of polishing CVD ZnS smoothly were previously discussed and presented. These parameters were acidic pH (~4.5) and low viscosity (~47 cP). MRF with such a unique MR fluid was shown to reduce surface artifacts in the form of pebbles; however,more » surface microroughness was still relatively high because of the absence of a polishing abrasive in the formulation. In this study, we examine the effect of two polishing abrasives—alumina and nanodiamond—on the surface finish of several CVD ZnS substrates, and on other important IR polycrystalline materials that were finished with acidic MR fluids containing these two polishing abrasives. Surface microroughness results obtained were as low as ~28 nm peak-to-valley and ~6-nm root mean square.« less

Influence of Surface Finishing on the Oxidation Behaviour of VPS MCrAlY Coatings

NASA Astrophysics Data System (ADS)

Fossati, Alessio; di Ferdinando, Martina; Bardi, Ugo; Scrivani, Andrea; Giolli, Carlo

2012-03-01

CoNiCrAlY coatings were produced by means of the vacuum plasma spraying (VPS) process onto CMSX-4 single crystal nickel superalloy disk substrates. As-sprayed samples were annealed at high temperatures in low vacuum. Three kinds of finishing processes were carried out, producing three types of samples: as-sprayed, mechanically smoothed by grinding, ground and PVD coated by using aluminum targets in an oxygen atmosphere. Samples were tested under isothermal conditions, in air, at 1000 °C, and up to 5000 h. Morphological, microstructural and compositional analyses were performed on the coated samples in order to assess the high temperature oxidation behavior provided by the three different surface finishing processes. Several differences were observed: grinding operations decrease the oxidation resistance, whereas the PVD process can increase the performances over longer time with respect of the as-sprayed samples.

Enhanced Ultra-Wideband (UWB) Circular Monopole Antenna with Electromagnetic Band Gap (EBG) Surface and Director

DTIC Science & Technology

2014-08-01

Enhanced Ultra-Wideband (UWB) Circular Monopole Antenna with Electromagnetic Band Gap (EBG) Surface and Director by Amir I Zaghloul, Youn M... Antenna with Electromagnetic Band Gap (EBG) Surface and Director Amir I Zaghloul, Youn M Lee, Gregory A Mitchell, and Theodore K Anthony...DATES COVERED (From - To) 4. TITLE AND SUBTITLE Enhanced Ultra-Wideband (UWB) Circular Monopole Antenna with Electromagnetic Band Gap (EBG

Ultra-precise tracking control of piezoelectric actuators via a fuzzy hysteresis model.

PubMed

Li, Pengzhi; Yan, Feng; Ge, Chuan; Zhang, Mingchao

2012-08-01

In this paper, a novel Takagi-Sugeno (T-S) fuzzy system based model is proposed for hysteresis in piezoelectric actuators. The antecedent and consequent structures of the fuzzy hysteresis model (FHM) can be, respectively, identified on-line through uniform partition approach and recursive least squares (RLS) algorithm. With respect to controller design, the inverse of FHM is used to develop a feedforward controller to cancel out the hysteresis effect. Then a hybrid controller is designed for high-performance tracking. It combines the feedforward controller with a proportional integral differential (PID) controller favourable for stabilization and disturbance compensation. To achieve nanometer-scale tracking precision, the enhanced adaptive hybrid controller is further developed. It uses real-time input and output data to update FHM, thus changing the feedforward controller to suit the on-site hysteresis character of the piezoelectric actuator. Finally, as to 3 cases of 50 Hz sinusoidal, multiple frequency sinusoidal and 50 Hz triangular trajectories tracking, experimental results demonstrate the efficiency of the proposed controllers. Especially, being only 0.35% of the maximum desired displacement, the maximum error of 50 Hz sinusoidal tracking is greatly reduced to 5.8 nm, which clearly shows the ultra-precise nanometer-scale tracking performance of the developed adaptive hybrid controller.

Study of the effect of tribo-materials and surface finish on the lubricant performance of new halogen-free room temperature ionic liquids

NASA Astrophysics Data System (ADS)

Saurín, N.; Minami, I.; Sanes, J.; Bermúdez, M. D.

2016-03-01

The present work evaluates different materials and surface finish in the presence of newly designed, hydrophobic halogen-free room temperature ionic liquids (RTILs) as lubricants. A reciprocating tribo-tester was employed with steel-ceramic and steel-thermosetting epoxy resin contacts under boundary lubrication conditions. Four different tetraalkylphosphonium organosilanesulfonate RTILs provided excellent lubricating performance, with friction coefficients as low as 0.057, and non-measurable wear for the higher roughness machine-finish stainless steel flat against sapphire balls, in the case of the lubricants containing the 2-trimethylsilylethanesulfonate anion. Higher friction coefficients of the order of 0.1 and wear volumes of the order of 10-4 mm3 were observed for the lower roughness fine-finished flat stainless steel surface. All RTILs prevent wear of epoxy resin against stainless steel balls, with friction coefficients in the range of 0.03-0.06. EDX analysis shows the presence of RTILs on the stainless steel surfaces after the tribological tests. Under the experimental conditions, no corrosive processes were observed.

Ultra wideband surface wave communications

NASA Astrophysics Data System (ADS)

Lacomb, Julie Anne

Ultra Wideband (UWB), an impulse carrier waveform, was applied at HF-VHF frequencies to utilize surface wave propagation. UWB involves the propagation of transient pulses rather than continuous waves which makes the system easier to implement, inexpensive, low power and small. Commercial UWB for wireless personal area networks is 3.1 to 10.6 GHz band as approved by the FCC with ranges up to 12 ft. The use of surface wave propagation (instead of commercial SHF UWB) extends the communication range. Surface wave is a means of propagation where the wave is guided by the surface of the Earth. Surface wave is efficient at low frequencies, VLF to HF. The UWB HF channel was modeled and also experimentally characterized. The Federal Communications Commission (FCC) defines UWB as a signal with either a fractional bandwidth of 20% of the center frequency or a bandwidth of 500MHz. Designing an antenna to operate over the 20% bandwidth requirement of UWB is one of the greatest challenges. Two different antenna designs are presented, a spoke top antenna and a traveling wave antenna with photonic bandgap. These designs were implemented at the commercial UWB frequencies (3.1--10.6 GHz) due to availability of modeling tools for the higher frequencies, the reduced antenna size and the availability of measurement facilities. The spoke top was optimum for replication of the time domain input signal. The traveling wave antenna with photonic bandgap demonstrated increased impedance bandwidth of the antenna.

The influence of temperature and humidity on printed wiring board surface finishes: Immersion tin vs organic azoles

NASA Astrophysics Data System (ADS)

Ray, U.; Artaki, I.; Gordon, H. M.; Vianco, P. T.

1994-08-01

Substitution of lead-free solders in electronic assemblies requires changes in the conventional Sn:Pb finishes on substrates and component leads to prevent contamination of the candidate lead-free solder. Options for solderability preservative coatings on the printed wiring board include organic (azole or rosin/resin based) films and tin-based plated metallic coatings. This paper compares the solderability performance and corrosion protection effectiveness of electroless tin coatings vs organic azole films after exposure to a series of humidity and thermal cycling conditions. The solderability of immersion tin is directly related to the tin oxide growth on the surface and is not affected by the formation of SnCu intermetallic phases as long as the intermetallic phase is underneath a protective Sn layer. Thin azole films decompose upon heating in the presence of oxygen and lead to solderability degradation. Evaluations of lead-free solder pastes for surface mount assembly applications indicate that immersion tin significantly improves the spreading of Sn:Ag and Sn:Bi alloys as compared to azole surface finishes.

Endocrine response to an ultra-marathon in pre- and post-menopausal women.

PubMed

Copeland, J L; Verzosa, M L S

2014-06-01

Ultra-endurance competitions are becoming increasingly popular but there is limited research on female participants. The purpose of this study was to examine changes in estrogen and the IGF-I system in women after an ultra-marathon. Six pairs of pre- and post- menopausal women were matched for race finish times;mean finish time was 20 hours. Blood samples were drawn 24 hours before the race, at the finish, and 24 hours into recovery. Samples were analysed for estradiol, total IGF-I, IGFBP-1, and intact IGFBP-3. There was a significant increase in estradiol following the race in both groups (P < 0.05). Total IGF-I decreased after the race (P < 0.01) and remained lower in recovery. IGFBP-1 increased after the race (P < 0.001) but returned to pre-race levels after 24 hours, while intact IGFBP-3 was significantly lower post-race and in recovery (P < 0.001). Postmenopausal women had significantly lower estradiol at baseline, but there were no other group differences. These results demonstrate that among recreational female runners, an ultra-marathon is associated with IGF system changes that are consistent with an energy-deficient, catabolic state. Further research is needed to confirm the effect of these endocrine changes on health and performance.

Imprinting high-gradient topographical structures onto optical surfaces using magnetorheological finishing: manufacturing corrective optical elements for high-power laser applications.

PubMed

Menapace, Joseph A; Ehrmann, Paul E; Bayramian, Andrew J; Bullington, Amber; Di Nicola, Jean-Michel G; Haefner, Constantin; Jarboe, Jeffrey; Marshall, Christopher; Schaffers, Kathleen I; Smith, Cal

2016-07-01

Corrective optical elements form an important part of high-precision optical systems. We have developed a method to manufacture high-gradient corrective optical elements for high-power laser systems using deterministic magnetorheological finishing (MRF) imprinting technology. Several process factors need to be considered for polishing ultraprecise topographical structures onto optical surfaces using MRF. They include proper selection of MRF removal function and wheel sizes, detailed MRF tool and interferometry alignment, and optimized MRF polishing schedules. Dependable interferometry also is a key factor in high-gradient component manufacture. A wavefront attenuating cell, which enables reliable measurement of gradients beyond what is attainable using conventional interferometry, is discussed. The results of MRF imprinting a 23 μm deep structure containing gradients over 1.6 μm / mm onto a fused-silica window are presented as an example of the technique's capabilities. This high-gradient element serves as a thermal correction plate in the high-repetition-rate advanced petawatt laser system currently being built at Lawrence Livermore National Laboratory.

16 CFR 1508.7 - Construction and finishing.

Code of Federal Regulations, 2010 CFR

2010-01-01

... REGULATIONS REQUIREMENTS FOR FULL-SIZE BABY CRIBS § 1508.7 Construction and finishing. (a) All wood surfaces shall be smooth and free from splinters. (b) All wood parts shall be free from splits, cracks, or other... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Construction and finishing. 1508.7 Section...

Effect of Hardness, Surface Finish and Grain Size on Rolling Contact Fatigue Life of M50 Bearing Steel

DTIC Science & Technology

1958-01-01

the surface-finish range desired, differ- cessary in order to establish optimum conditions ent grades of grinding wheels were used on the cen- for...FATIGUEHESULTS 05 MT O AT VARIO0 QRIAIN U- ZES HABLESSES , AND SURFACE INISHE.. TEbT BEOLTJ OF 010 LOBE IN DE1CEtDIh, (’D,6 Hard- Gr-in Sur(...(e Wiebull Ha

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

NASA Astrophysics Data System (ADS)

Kataraki, Pramod S.; Salman Abu Mansor, Mohd

2018-03-01

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

Apparatus for precision micromachining with lasers

DOEpatents

Chang, Jim J.; Dragon, Ernest P.; Warner, Bruce E.

1998-01-01

A new material processing apparatus using a short-pulsed, high-repetition-rate visible laser for precision micromachining utilizes a near diffraction limited laser, a high-speed precision two-axis tilt-mirror for steering the laser beam, an optical system for either focusing or imaging the laser beam on the part, and a part holder that may consist of a cover plate and a back plate. The system is generally useful for precision drilling, cutting, milling and polishing of metals and ceramics, and has broad application in manufacturing precision components. Precision machining has been demonstrated through percussion drilling and trepanning using this system. With a 30 W copper vapor laser running at multi-kHz pulse repetition frequency, straight parallel holes with size varying from 500 microns to less than 25 microns and with aspect ratios up to 1:40 have been consistently drilled with good surface finish on a variety of metals. Micromilling and microdrilling on ceramics using a 250 W copper vapor laser have also been demonstrated with good results. Materialogroaphic sections of machined parts show little (submicron scale) recast layer and heat affected zone.

Apparatus for precision micromachining with lasers

DOEpatents

Chang, J.J.; Dragon, E.P.; Warner, B.E.

1998-04-28

A new material processing apparatus using a short-pulsed, high-repetition-rate visible laser for precision micromachining utilizes a near diffraction limited laser, a high-speed precision two-axis tilt-mirror for steering the laser beam, an optical system for either focusing or imaging the laser beam on the part, and a part holder that may consist of a cover plate and a back plate. The system is generally useful for precision drilling, cutting, milling and polishing of metals and ceramics, and has broad application in manufacturing precision components. Precision machining has been demonstrated through percussion drilling and trepanning using this system. With a 30 W copper vapor laser running at multi-kHz pulse repetition frequency, straight parallel holes with size varying from 500 microns to less than 25 microns and with aspect ratios up to 1:40 have been consistently drilled with good surface finish on a variety of metals. Micromilling and microdrilling on ceramics using a 250 W copper vapor laser have also been demonstrated with good results. Materialographic sections of machined parts show little (submicron scale) recast layer and heat affected zone. 1 fig.

KDP Aqueous Solution-in-Oil Microemulsion for Ultra-Precision Chemical-Mechanical Polishing of KDP Crystal.

PubMed

Dong, Hui; Wang, Lili; Gao, Wei; Li, Xiaoyuan; Wang, Chao; Ji, Fang; Pan, Jinlong; Wang, Baorui

2017-03-09

A novel functional KH₂PO₄ (KDP) aqueous solution-in-oil (KDP aq/O) microemulsion system for KDP crystal ultra-precision chemical-mechanical polishing (CMP) was prepared. The system, which consisted of decanol, Triton X-100, and KH₂PO₄ aqueous solution, was available at room temperature. The functional KDP aq/O microemulsion system was systematically studied and applied as polishing solution to KDP CMP technology. In this study, a controlled deliquescent mechanism was proposed for KDP polishing with the KDP aq/O microemulsion. KDP aqueous solution, the chemical etchant in the polishing process, was caged into the micelles in the microemulsion, leading to a limitation of the reaction between the KDP crystal and KDP aqueous solution only if the microemulsion was deformed under the effect of the external force. Based on the interface reaction dynamics, KDP aqueous solutions with different concentrations ( c KDP ) were applied to replace water in the traditional water-in-oil (W/O) microemulsion. The practicability of the controlled deliquescent mechanism was proved by the decreasing material removal rate (MRR) with the increasing of the c KDP . As a result, the corrosion pits on the KDP surface were avoided to some degree. Moreover, the roughnesses of KDP with KDP aq/O microemulsion ( c KDP was changed from 10 mM to 100 mM) as polishing solutions were smaller than that with the W/O microemulsion. The smallest surface root-mean-square roughness of 1.5 nm was obtained at a 30 mmol/L KDP aq solution, because of the most appropriate deliquescent rate and MRR.

16 CFR 1509.8 - Construction and finishing.

Code of Federal Regulations, 2010 CFR

2010-01-01

... REGULATIONS REQUIREMENTS FOR NON-FULL-SIZE BABY CRIBS § 1509.8 Construction and finishing. (a) All wood surfaces of non-full-size baby cribs shall be smooth and free from splinters. (b) All wood parts of non... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Construction and finishing. 1509.8 Section...

Multiscale analysis of replication technique efficiency for 3D roughness characterization of manufactured surfaces

NASA Astrophysics Data System (ADS)

Jolivet, S.; Mezghani, S.; El Mansori, M.

2016-09-01

The replication of topography has been generally restricted to optimizing material processing technologies in terms of statistical and single-scale features such as roughness. By contrast, manufactured surface topography is highly complex, irregular, and multiscale. In this work, we have demonstrated the use of multiscale analysis on replicates of surface finish to assess the precise control of the finished replica. Five commercial resins used for surface replication were compared. The topography of five standard surfaces representative of common finishing processes were acquired both directly and by a replication technique. Then, they were characterized using the ISO 25178 standard and multiscale decomposition based on a continuous wavelet transform, to compare the roughness transfer quality at different scales. Additionally, atomic force microscope force modulation mode was used in order to compare the resins’ stiffness properties. The results showed that less stiff resins are able to replicate the surface finish along a larger wavelength band. The method was then tested for non-destructive quality control of automotive gear tooth surfaces.

Assembling Precise Truss Structures With Minimal Stresses

NASA Technical Reports Server (NTRS)

Sword, Lee F.

1996-01-01

Improved method of assembling precise truss structures involves use of simple devices. Tapered pins that fit in tapered holes indicate deviations from prescribed lengths. Method both helps to ensure precision of finished structures and minimizes residual stresses within structures.

Similarities and Differences in Pacing Patterns in a 161-km and 101-km Ultra-Distance Road Race.

PubMed

Tan, Philip L S; Tan, Frankie H Y; Bosch, Andrew N

2016-08-01

Tan, PLS, Tan, FHY, and Bosch, AN. Similarities and differences in pacing patterns in a 161-km and 101-km ultra-distance road race. J Strength Cond Res 30(8): 2145-2155, 2016-The purpose of this study was to establish and compare the pacing patterns of fast and slow finishers in a tropical ultra-marathon. Data were collected from the Craze Ultra-marathon held on the 22nd and 21st of September in 2012 and 2013, respectively. Finishers of the 161-km (N = 47) and 101-km (N = 120) categories of the race were divided into thirds (groups A-C) by merit of finishing time. Altogether, 17 and 11 split times were recorded for the 161-km and 101-km finishers, respectively, and used to calculate the mean running speed for each distance segment. Running speed for the first segment was normalized to 100, with all subsequent splits adjusted accordingly. Running speed during the last 5 km was calculated against the mean race pace to establish the existence of an end spurt. A reverse J-shaped pacing profile was demonstrated in all groups for both distance categories and only 38% of the finishers executed an end spurt. In the 101-km category, in comparison with groups B and C, group A maintained a significantly more even pace (p = 0.013 and 0.001, respectively) and completed the race at a significantly higher percent of initial starting speed (p = 0.001 and 0.001, respectively). Descriptive data also revealed that the top 5 finishers displayed a "herd-behavior" by staying close to the lead runner in the initial portion of the race. These findings demonstrate that to achieve a more even pace, recreational ultra-runners should adopt a patient sustainable starting speed, with less competitive runners setting realistic performance goals whereas competitive runners with a specific time goal to consider running in packs of similar pace.

Study on effect of tool electrodes on surface finish during electrical discharge machining of Nitinol

NASA Astrophysics Data System (ADS)

Sahu, Anshuman Kumar; Chatterjee, Suman; Nayak, Praveen Kumar; Sankar Mahapatra, Siba

2018-03-01

Electrical discharge machining (EDM) is a non-traditional machining process which is widely used in machining of difficult-to-machine materials. EDM process can produce complex and intrinsic shaped component made of difficult-to-machine materials, largely applied in aerospace, biomedical, die and mold making industries. To meet the required applications, the EDMed components need to possess high accuracy and excellent surface finish. In this work, EDM process is performed using Nitinol as work piece material and AlSiMg prepared by selective laser sintering (SLS) as tool electrode along with conventional copper and graphite electrodes. The SLS is a rapid prototyping (RP) method to produce complex metallic parts by additive manufacturing (AM) process. Experiments have been carried out varying different process parameters like open circuit voltage (V), discharge current (Ip), duty cycle (τ), pulse-on-time (Ton) and tool material. The surface roughness parameter like average roughness (Ra), maximum height of the profile (Rt) and average height of the profile (Rz) are measured using surface roughness measuring instrument (Talysurf). To reduce the number of experiments, design of experiment (DOE) approach like Taguchi’s L27 orthogonal array has been chosen. The surface properties of the EDM specimen are optimized by desirability function approach and the best parametric setting is reported for the EDM process. Type of tool happens to be the most significant parameter followed by interaction of tool type and duty cycle, duty cycle, discharge current and voltage. Better surface finish of EDMed specimen can be obtained with low value of voltage (V), discharge current (Ip), duty cycle (τ) and pulse on time (Ton) along with the use of AlSiMg RP electrode.

Development of ultra-precision micro-cavity measurement technique in HIT-UOI

NASA Astrophysics Data System (ADS)

Cui, Jiwen; Li, Lei; Tan, Jiubin

2010-08-01

Micro cavities with high aspect ratio are widely used in different fields including aerospace and defense industries with the development of manufacturing technology. So how to measure the dimension of these cavities has become one of the major research subjects in the field of measurement and instrument. This paper describes some activities of the precision micro cavity measurement technique in Center of Ultra-precision Optoelectronic Instrument (UOI), Harbin Institute of Technology (HIT). The key issue of micro cavity measurement in UOI is called touch-trigger measurement method. The first scheme is double optical fiber coupling, in which light coming from the incident optical fiber is transmitted in the reversal direction via the optical fiber coupling into the effluent optical fiber, the lateral displacement of the touch-trigger sensor is transformed into the deflexion of light coming out from the effluent optical fiber, and the deflexion is transformed into an image signal by the object lens and CCD capturing system. And the second scheme is micro focal-length collimation, in which a fiber stem with a ball mounted on its end is used as a probe and a small segment of it is used as a cylindrical lens to collimate a point light source and image it to a camera, the deflection of the fiber stem can be inferred from the change in image acquired by the camera with ultrahigh displacement sensitivity. Experiments for these activities will be given with a focus on the measurement results and repeatability uncertainty.

Research on the magnetorheological finishing (MRF) technology with dual polishing heads

NASA Astrophysics Data System (ADS)

Huang, Wen; Zhang, Yunfei; He, Jianguo; Zheng, Yongcheng; Luo, Qing; Hou, Jing; Yuan, Zhigang

2014-08-01

Magnetorheological finishing (MRF) is a key polishing technique capable of rapidly converging to the required surface figure. Due to the deficiency of general one-polishing-head MRF technology, a dual polishing heads MRF technology was studied and a dual polishing heads MRF machine with 8 axes was developed. The machine has the ability to manufacture large aperture optics with high figure accuracy. The large polishing head is suitable for polishing large aperture optics, controlling large spatial length's wave structures, correcting low-medium frequency errors with high removal rates. While the small polishing head has more advantages in manufacturing small aperture optics, controlling small spatial wavelength's wave structures, correcting mid-high frequency and removing nanoscale materials. Material removal characteristic and figure correction ability for each of large and small polishing head was studied. Each of two polishing heads respectively acquired stable and valid polishing removal function and ultra-precision flat sample. After a single polishing iteration using small polishing head, the figure error in 45mm diameter of a 50 mm diameter plano optics was significantly improved from 0.21λ to 0.08λ by PV (RMS 0.053λ to 0.015λ). After three polishing iterations using large polishing head , the figure error in 410mm×410mm of a 430mm×430mm large plano optics was significantly improved from 0.40λ to 0.10λ by PV (RMS 0.068λ to 0.013λ) .This results show that the dual polishing heads MRF machine not only have good material removal stability, but also excellent figure correction capability.

Controlled nanostructrures formation by ultra fast laser pulses for color marking.

PubMed

Dusser, B; Sagan, Z; Soder, H; Faure, N; Colombier, J P; Jourlin, M; Audouard, E

2010-02-01

Precise nanostructuration of surface and the subsequent upgrades in material properties is a strong outcome of ultra fast laser irradiations. Material characteristics can be designed on mesoscopic scales, carrying new optical properties. We demonstrate in this work, the possibility of achieving material modifications using ultra short pulses, via polarization dependent structures generation, that can generate specific color patterns. These oriented nanostructures created on the metal surface, called ripples, are typically smaller than the laser wavelength and in the range of visible spectrum. In this way, a complex colorization process of the material, involving imprinting, calibration and reading, has been performed to associate a priori defined colors. This new method based on the control of the laser-driven nanostructure orientation allows cumulating high quantity of information in a minimal surface, proposing new applications for laser marking and new types of identifying codes.

KDP Aqueous Solution-in-Oil Microemulsion for Ultra-Precision Chemical-Mechanical Polishing of KDP Crystal

PubMed Central

Dong, Hui; Wang, Lili; Gao, Wei; Li, Xiaoyuan; Wang, Chao; Ji, Fang; Pan, Jinlong; Wang, Baorui

2017-01-01

A novel functional KH2PO4 (KDP) aqueous solution-in-oil (KDP aq/O) microemulsion system for KDP crystal ultra-precision chemical-mechanical polishing (CMP) was prepared. The system, which consisted of decanol, Triton X-100, and KH2PO4 aqueous solution, was available at room temperature. The functional KDP aq/O microemulsion system was systematically studied and applied as polishing solution to KDP CMP technology. In this study, a controlled deliquescent mechanism was proposed for KDP polishing with the KDP aq/O microemulsion. KDP aqueous solution, the chemical etchant in the polishing process, was caged into the micelles in the microemulsion, leading to a limitation of the reaction between the KDP crystal and KDP aqueous solution only if the microemulsion was deformed under the effect of the external force. Based on the interface reaction dynamics, KDP aqueous solutions with different concentrations (cKDP) were applied to replace water in the traditional water-in-oil (W/O) microemulsion. The practicability of the controlled deliquescent mechanism was proved by the decreasing material removal rate (MRR) with the increasing of the cKDP. As a result, the corrosion pits on the KDP surface were avoided to some degree. Moreover, the roughnesses of KDP with KDP aq/O microemulsion (cKDP was changed from 10 mM to 100 mM) as polishing solutions were smaller than that with the W/O microemulsion. The smallest surface root-mean-square roughness of 1.5 nm was obtained at a 30 mmol/L KDP aq solution, because of the most appropriate deliquescent rate and MRR. PMID:28772632

Effect of surface roughness and stainless steel finish on Listeria monocytogenes attachment and biofilm formation.

PubMed

Rodriguez, Andres; Autio, Wesley R; McLandsborough, Lynne A

2008-01-01

The purpose of this study was to evaluate the effect of surface roughness (Ra) and finish of mechanically polished stainless steel (Ra = 0.26 +/- 0.05, 0.49 +/- 0.10, and 0.69 +/- 0.05 microm) and electropolished stainless steel (Ra = 0.16 +/- 0.06, 0.40 +/- 0.003, and 0.67 +/- 0.02 microm) on Listeria adhesion and biofilm formation. A four-strain cocktail of Listeria monocytogenes was used. Each strain (0.1%) was added to 200 ml of tryptic soy broth (TSB), and coupons were inserted to the mixture for 5 min. For biofilm formation, coupons with adhesive cells were incubated in 1:20 diluted TSB at 32 degrees C for 48 h. The experiment was performed by a randomized block design. Our results show that the level of Listeria present after 48 h of incubation (mean = 7 log CFU/cm2) was significantly higher than after 5 min (mean = 6.0 log CFU/cm2) (P < 0.01). No differences in initial adhesion were seen in mechanically finished (mean = 6.7 log CFU/cm2) when compared with electropolished stainless steel (mean = 6.7 log CFU/cm2) (P > 0.05). Listeria initial adhesion (values ranged from 5.9 to 6.1 log CFU/cm2) or biofilm formation (values ranged from 6.9 to 7.2 log CFU/cm2) was not significantly correlated with Ra values (P > 0.05). Image analysis with an atomic force microscope showed that bacteria did not colonize the complete surface after 48 h but were individual cells or grouped in microcolonies that ranged from 5 to 10 microm in diameter and one to three cell layers in thickness. Exopolymeric substances were observed to be associated with the colonies. According to our results, electropolishing stainless steel does not pose a significant advantage for food sanitation over mechanically finished stainless steel.

Analysis of the Material Removal Rate in Magnetic Abrasive Finishing of Thin Film Coated Pyrex Glass

NASA Astrophysics Data System (ADS)

Lee, Hee Hwan; Lee, Seoung Hwan

The material removal rate (MRR) during precision finishing/polishing is a key factor, which dictates the process performance. Moreover, the MRR or wear rate is closely related to the material/part reliability. For nanoscale patterning and/or planarization on nano-order thickness coatings, the prediction and in-process monitoring of the MRR is necessary, because the process is not characterizable due to size effects and material property/process condition variations as a result of the coating/substrate interactions. The purpose of this research was to develop a practical methodology for the prediction and in-process monitoring of MRR during nanoscale finishing of coated surfaces. Using a specially designed magnetic abrasive finishing (MAF) and acoustic emission (AE) monitoring setup, experiments were carried out on indium-zinc-oxide (IZO) coated Pyrex glasses. After a given polishing time interval, AFM indentation was conducted for each workpiece sample to measure the adhesion force variations of the coating layers (IZO), which are directly related to the MRR changes. The force variation and AE monitoring data were compared to the MRR calculated form the surface measurement (Nanoview) results. The experimental results demonstrate strong correlations between AFM indentation and MRR measurement data. In addition, the monitored AE signals show sensitivity of the material structure variations of the coating layer, as the polishing progresses.

Finishing procedures in orthodontic-surgical cases.

PubMed

Brunel, Jean-Michel

2015-09-01

To ensure optimal results, we must do our utmost to achieve targets based on order, symmetry and precision, our ultimate aim being to strive towards the desired harmony, planned contrast and exact proportions. Orthodontic-surgical treatments require specific finishing procedures, which most often call for multidisciplinary, or even transdisciplinary, collaboration. Finishing will involve the dental arches just as much as the orofacial environment. Above all, treatment of this kind demands a highly targeted approach in combination with well-defined and perfectly executed techniques. To finish a case satisfactorily, reasonable targets should be aimed for to ensure they are achieved. One must be ambitious and yet wise. A tight alliance of surgeon and orthodontist will nurture convincing and achievable projects and good, lifelong outcomes. Following the consolidation phase, roughly 4 to 6 weeks post-surgery, we can initiate the final orthodontic treatment, which, in effect, constitutes a mini-treatment in its own right. "Details make perfection, but perfection is not a detail" (Leonardo Da Vinci). "A lucid mind is the ante-chamber of intelligence" (Léo Ferré). In the order of life, every form of unity is always unique, and if each of us is unique, it is because everyone else is too. Ambition, wisdom, lucidity and efficiency will guarantee a successful result, the successful result. We must not be mere observers of our treatments, but the architect, project manager and site foreman at one and the same time. One could talk ad infinitum about finishing orthodontic-surgical cases because everything else leads up to the case-finishing and even the fullest description could never be exhaustive. Copyright © 2015 CEO. Published by Elsevier Masson SAS. All rights reserved.

Age-related changes in ultra-triathlon performances

PubMed Central

2012-01-01

Background The age-related decline in performance has been investigated in swimmers, runners and triathletes. No study has investigated the age-related performance decline in ultra-triathletes. The purpose of this study was to analyse the age-related declines in swimming, cycling, running and overall race time for both Triple Iron ultra-triathlon (11.4-km swimming, 540-km cycling and 126.6-km running) and Deca Iron ultra-triathlon (38-km swimming, 1,800-km cycling and 420-km running). Methods The age and performances of 423 male Triple Iron ultra-triathletes and 119 male Deca Iron ultra-triathletes were analysed from 1992 to 2010 using regression analyses and ANOVA. Results The mean age of the finishers was significantly higher for Deca Iron ultra-triathletes (41.3 ± 3.1 years) compared to a Triple Iron ultra-triathletes (38.5 ± 3.3 years) (P < 0.05). For both ultra-distances, the fastest overall race times were achieved between the ages of 25 and 44 years. Deca Iron ultra-triathletes achieved the same level of performance in swimming and cycling between 25 and 54 years of age. Conclusions The magnitudes of age-related declines in performance in the three disciplines of ultra-triathlon differ slightly between Triple and Deca Iron ultra-triathlon. Although the ages of Triple Iron ultra-triathletes were on average younger compared to Deca Iron ultra-triathletes, the fastest race times were achieved between 25 and 44 years for both distances. Further studies should investigate the motivation and training of ultra-triathletes to gain better insights in ultra-triathlon performance. PMID:23849327

Removal of Lattice Imperfections that Impact the Optical Quality of Ti:Sapphire using Advanced Magnetorheological Finishing Techniques

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

Menapace, J A; Schaffers, K I; Bayramian, A J

2007-10-09

Ti:sapphire has become the premier lasing medium material for use in solid-state femtosecond high-peak power laser systems because of its wide wavelength tuning range. With a tuneable range from 680 to 1100 nm, peaking at 800 nm, Ti:sapphire lasing crystals can easily be tuned to the required pump wavelength and provide very high pump brightness due to their good beam quality and high output power of typically several watts. Femtosecond lasers are used for precision cutting and machining of materials ranging from steel to tooth enamel to delicate heart tissue and high explosives. These ultra-short pulses are too brief tomore » transfer heat or shock to the material being cut, which means that cutting, drilling, and machining occur with virtually no damage to surrounding material. Furthermore, these lasers can cut with high precision, making hairline cuts of less than 100 microns in thick materials along a computer-generated path. Extension of laser output to higher energies is limited by the size of the amplification medium. Yields of high quality large diameter crystals have been constrained by lattice distortions that may appear in the boule limiting the usable area from which high quality optics can be harvested. Lattice distortions affect the transmitted wavefront of these optics which ultimately limits the high-end power output and efficiency of the laser system, particularly when operated in multi-pass mode. To make matters even more complicated, Ti:sapphire is extremely hard (Mohs hardness of 9 with diamond being 10) which makes it extremely difficult to accurately polish using conventional methods without subsurface damage or significant wavefront error. In this presentation, we demonstrate for the first time that Magnetorheological finishing (MRF) can be used to compensate for the lattice distortions in Ti:sapphire by perturbing the transmitted wavefront. The advanced MRF techniques developed allow for precise polishing of the optical inverse of lattice

Imprinting high-gradient topographical structures onto optical surfaces using magnetorheological finishing: Manufacturing corrective optical elements for high-power laser applications

DOE PAGES

Menapace, Joseph A.; Ehrmann, Paul E.; Bayramian, Andrew J.; ...

2016-03-15

Corrective optical elements form an important part of high-precision optical systems. We have developed a method to manufacture high-gradient corrective optical elements for high-power laser systems using deterministic magnetorheological finishing (MRF) imprinting technology. Several process factors need to be considered for polishing ultraprecise topographical structures onto optical surfaces using MRF. They include proper selection of MRF removal function and wheel sizes, detailed MRF tool and interferometry alignment, and optimized MRF polishing schedules. Dependable interferometry also is a key factor in high-gradient component manufacture. A wavefront attenuating cell, which enables reliable measurement of gradients beyond what is attainable using conventional interferometry,more » is discussed. The results of MRF imprinting a 23 μm deep structure containing gradients over 1.6 μm / mm onto a fused-silica window are presented as an example of the technique’s capabilities. As a result, this high-gradient element serves as a thermal correction plate in the high-repetition-rate advanced petawatt laser system currently being built at Lawrence Livermore National Laboratory.« less

Effects of Surface Finishes and Current Stressing on Interfacial Reaction Characteristics of Sn-3.0Ag-0.5Cu Solder Bumps

NASA Astrophysics Data System (ADS)

Kim, Jae-Myeong; Jeong, Myeong-Hyeok; Yoo, Sehoon; Park, Young-Bae

2012-04-01

The effects of surface finishes on the in situ interfacial reaction characteristics of ball grid array (BGA) Sn-3.0Ag-0.5Cu lead-free solder bumps were investigated under annealing and electromigration (EM) test conditions of 130°C to 175°C with 5.0 × 103 A/cm2. During reflow and annealing, (Cu,Ni)6Sn5 intermetallic compound (IMC) formed at the interface of electroless nickel immersion gold (ENIG) finish. In the case of both immersion Sn and organic solderability preservative (OSP) finishes, Cu6Sn5 and Cu3Sn IMCs formed. Overall, the IMC growth velocity of ENIG was much lower than that of the other finishes. The activation energies of total IMCs were found to be 0.52 eV for ENIG, 0.78 eV for immersion Sn, and 0.72 eV for OSP. The ENIG finish appeared to present an effective diffusion barrier between the Cu substrate and the solder, which leads to better EM reliability in comparison with Cu-based pad systems. The failure mechanisms were explored in detail via in situ EM tests.

Reliable low precision simulations in land surface models

NASA Astrophysics Data System (ADS)

Dawson, Andrew; Düben, Peter D.; MacLeod, David A.; Palmer, Tim N.

2017-12-01

Weather and climate models must continue to increase in both resolution and complexity in order that forecasts become more accurate and reliable. Moving to lower numerical precision may be an essential tool for coping with the demand for ever increasing model complexity in addition to increasing computing resources. However, there have been some concerns in the weather and climate modelling community over the suitability of lower precision for climate models, particularly for representing processes that change very slowly over long time-scales. These processes are difficult to represent using low precision due to time increments being systematically rounded to zero. Idealised simulations are used to demonstrate that a model of deep soil heat diffusion that fails when run in single precision can be modified to work correctly using low precision, by splitting up the model into a small higher precision part and a low precision part. This strategy retains the computational benefits of reduced precision whilst preserving accuracy. This same technique is also applied to a full complexity land surface model, resulting in rounding errors that are significantly smaller than initial condition and parameter uncertainties. Although lower precision will present some problems for the weather and climate modelling community, many of the problems can likely be overcome using a straightforward and physically motivated application of reduced precision.

Generation of ultra-wideband achromatic Airy plasmons on a graphene surface.

PubMed

Guan, Chunying; Yuan, Tingting; Chu, Rang; Shen, Yize; Zhu, Zheng; Shi, Jinhui; Li, Ping; Yuan, Libo; Brambilla, Gilberto

2017-02-01

Tunable ultra-wideband achromatic plasmonic Airy beams are demonstrated on graphene surfaces. Surface plasmonic polaritons are excited using diffractive gratings. The phase and amplitude of plasmonic waves on the graphene surface are determined by the relative position between the grating arrays and the duty ratio of the grating unit cell, respectively. The transverse acceleration and nondiffraction properties of plasmonic waves are observed. The achromatic Airy plasmons with identical acceleration trajectory at different excited frequencies can be achieved by tuning dynamically the Fermi energy of graphene without reoptimizing the grating structures. The proposed devices may find applications in photonics integrations and surface optical manipulation.

The effects of surface finish and grain size on the strength of sintered silicon carbide

NASA Technical Reports Server (NTRS)

You, Y. H.; Kim, Y. W.; Lee, J. G.; Kim, C. H.

1985-01-01

The effects of surface treatment and microstructure, especially abnormal grain growth, on the strength of sintered SiC were studied. The surfaces of sintered SiC were treated with 400, 800 and 1200 grit diamond wheels. Grain growth was induced by increasing the sintering times at 2050 C. The beta to alpha transformation occurred during the sintering of beta-phase starting materials and was often accompanied by abnormal grain growth. The overall strength distributions were established using Weibull statistics. The strength of the sintered SiC is limited by extrinsic surface flaws in normal-sintered specimens. The finer the surface finish and grain size, the higher the strength. But the strength of abnormal sintering specimens is limited by the abnormally grown large tabular grains. The Weibull modulus increases with decreasing grain size and decreasing grit size for grinding.

Removal of Lattice Imperfections that Impact the Optical Quality of Ti:Sapphire using Advanced Magnetorheological Finishing Techniques

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

Menapace, J A; Schaffers, K I; Bayramian, A J

2008-02-26

Advanced magnetorheological finishing (MRF) techniques have been applied to Ti:sapphire crystals to compensate for sub-millimeter lattice distortions that occur during the crystal growing process. Precise optical corrections are made by imprinting topographical structure onto the crystal surfaces to cancel out the effects of the lattice distortion in the transmitted wavefront. This novel technique significantly improves the optical quality for crystals of this type and sets the stage for increasing the availability of high-quality large-aperture sapphire and Ti:sapphire optics in critical applications.

Precise orbit computation and sea surface modeling

NASA Technical Reports Server (NTRS)

Wakker, Karel F.; Ambrosius, B. A. C.; Rummel, R.; Vermaat, E.; Deruijter, W. P. M.; Vandermade, J. W.; Zimmerman, J. T. F.

1991-01-01

The research project described below is part of a long-term program at Delft University of Technology aiming at the application of European Remote Sensing satellite (ERS-1) and TOPEX/POSEIDON altimeter measurements for geophysical purposes. This program started in 1980 with the processing of Seasat laser range and altimeter height measurements and concentrates today on the analysis of Geosat altimeter data. The objectives of the TOPEX/POSEIDON research project are the tracking of the satellite by the Dutch mobile laser tracking system MTLRS-2, the computation of precise TOPEX/POSEIDON orbits, the analysis of the spatial and temporal distribution of the orbit errors, the improvement of ERS-1 orbits through the information obtained from the altimeter crossover difference residuals for crossing ERS-1 and TOPEX/POSEIDON tracks, the combination of ERS-1 and TOPEX/POSEIDON altimeter data into a single high-precision data set, and the application of this data set to model the sea surface. The latter application will focus on the determination of detailed regional mean sea surfaces, sea surface variability, ocean topography, and ocean currents in the North Atlantic, the North Sea, the seas around Indonesia, the West Pacific, and the oceans around South Africa.

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

PubMed

Pinto, Gustavo Da Col dos Santos; Dias, Kleber Campioni; Cruvinel, Diogo Rodrigues; Garcia, Lucas da Fonseca Roberti; Consani, Simonides; Pires-De-Souza, Fernanda de Carvalho Panzeri

2013-01-01

To assess the influence of finishing/polishing procedure on color stability (ΔE ) and surface roughness (R(a)) of composites (Heliomolar and Tetric - color A2) submitted to accelerated artificial aging (AAA). 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 R(a) (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. 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 R(a), Group F showed rougher samples than FF with statistically significant difference (P < 0.05). In spite of the surface differences, the different finishing/polishing procedures were not capable of providing color stability within the clinically acceptable limits.

Abrasive wear of resin composites as related to finishing and polishing procedures.

PubMed

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.

Design and control of the precise tracking bed based on complex electromechanical design theory

NASA Astrophysics Data System (ADS)

Ren, Changzhi; Liu, Zhao; Wu, Liao; Chen, Ken

2010-05-01

The precise tracking technology is wide used in astronomical instruments, satellite tracking and aeronautic test bed. However, the precise ultra low speed tracking drive system is one high integrated electromechanical system, which one complexly electromechanical design method is adopted to improve the efficiency, reliability and quality of the system during the design and manufacture circle. The precise Tracking Bed is one ultra-exact, ultra-low speed, high precision and huge inertial instrument, which some kind of mechanism and environment of the ultra low speed is different from general technology. This paper explores the design process based on complex electromechanical optimizing design theory, one non-PID with a CMAC forward feedback control method is used in the servo system of the precise tracking bed and some simulation results are discussed.

Fabrication of zero contact angle ultra-super hydrophilic surfaces.

PubMed

Jothi Prakash, C G; Clement Raj, C; Prasanth, R

2017-06-15

Zero contact angle surfaces have been created with the combined effect of nanostructure and UV illumination. The contact angle of titanium surface has been optimized to 3.25°±1°. with nanotubular structures through electrochemical surface modification. The porosity and surface energy of tubular TiO 2 layer play critical role over the surface wettability and the hydrophilicity of the surface. The surface free energy has been enhanced from 23.72mJ/m 2 (bare titanium surface) to 87.11mJ/m 2 (nanotubular surface). Similar surface with TiO 2 nanoparticles coating shows superhydrophilicity with contact angle up to 5.63°±0.95°. This implies liquid imbibition and surface curvature play a crucial role in surface hydrophilicity. The contact angle has been further reduced to 0°±0.86° by illuminating the surface with UV radiation. Results shows that by tuning the nanotube morphology, highly porous surfaces can be fabricated to reduce contact angle and enhance wettability. This study provides an insight into the inter-relationship between surface structural factors and ultra-superhydrophilic surfaces which can help to optimize thermal hydraulic and self cleaning surfaces. Copyright © 2017. Published by Elsevier Inc.

Enamel and Dentin Surface Finishing Influence on the Roughness and Microshear Bond Strength of a Lithium Silicate Glass-Ceramic for Laminate Veneers.

PubMed

Gonzaga, Carla Castiglia; Bravo, Ruth Peggy; Pavelski, Thiago Vinícius; Garcia, Paula Pontes; Correr, Gisele Maria; Leonardi, Denise Piotto; da Cunha, Leonardo Fernandes; Furuse, Adilson Yoshio

2015-01-01

Objectives. This study evaluated the influence of cavity surface finishing with diamond burs of different grit mounted on high-speed turbine and ultrasound on the roughness and microshear bond strength (MBS) of a lithium silicate glass-ceramic to enamel and dentin. Methods. Enamel and dentin specimens were divided into seven groups, according to the type of surface finishing: 1200-grit sandpaper (control), two different brands of medium-grit and fine-grit diamond burs in a high-speed turbine; medium-grit and fine-grit CVD (chemical vapor deposition) tips in an ultrasonic device. Roughness parameters (n = 5) and MSBS to a glass-ceramic (n = 10) were determined. Data were analyzed using ANOVA and Tukey's test (α = 5%). Results. Control group showed lower mean roughness readings and groups that used medium-grit diamond burs showed the highest mean roughness values. Regarding MSBS, there was no statistical difference when comparing the groups gritted with the same brand of medium- and fine-grit burs and tips. Conclusions. Cavity surface finishing influenced the roughness parameters and MSBS of a glass-ceramic to enamel and dentin. Medium-grit diamond burs in high-speed turbine showed the highest mean roughness values. Fine-grit CVD tips in ultrasound presented the highest MSBS values for both enamel and dentin.

Enamel and Dentin Surface Finishing Influence on the Roughness and Microshear Bond Strength of a Lithium Silicate Glass-Ceramic for Laminate Veneers

PubMed Central

Gonzaga, Carla Castiglia; Bravo, Ruth Peggy; Pavelski, Thiago Vinícius; Garcia, Paula Pontes; Correr, Gisele Maria; Leonardi, Denise Piotto; da Cunha, Leonardo Fernandes; Furuse, Adilson Yoshio

2015-01-01

Objectives. This study evaluated the influence of cavity surface finishing with diamond burs of different grit mounted on high-speed turbine and ultrasound on the roughness and microshear bond strength (MBS) of a lithium silicate glass-ceramic to enamel and dentin. Methods. Enamel and dentin specimens were divided into seven groups, according to the type of surface finishing: 1200-grit sandpaper (control), two different brands of medium-grit and fine-grit diamond burs in a high-speed turbine; medium-grit and fine-grit CVD (chemical vapor deposition) tips in an ultrasonic device. Roughness parameters (n = 5) and MSBS to a glass-ceramic (n = 10) were determined. Data were analyzed using ANOVA and Tukey's test (α = 5%). Results. Control group showed lower mean roughness readings and groups that used medium-grit diamond burs showed the highest mean roughness values. Regarding MSBS, there was no statistical difference when comparing the groups gritted with the same brand of medium- and fine-grit burs and tips. Conclusions. Cavity surface finishing influenced the roughness parameters and MSBS of a glass-ceramic to enamel and dentin. Medium-grit diamond burs in high-speed turbine showed the highest mean roughness values. Fine-grit CVD tips in ultrasound presented the highest MSBS values for both enamel and dentin. PMID:27347507

Laser Induced Damage of Potassium Dihydrogen Phosphate (KDP) Optical Crystal Machined by Water Dissolution Ultra-Precision Polishing Method

PubMed Central

Gao, Hang; Wang, Xu; Guo, Dongming; Liu, Ziyuan

2018-01-01

Laser induced damage threshold (LIDT) is an important optical indicator for nonlinear Potassium Dihydrogen Phosphate (KDP) crystal used in high power laser systems. In this study, KDP optical crystals are initially machined with single point diamond turning (SPDT), followed by water dissolution ultra-precision polishing (WDUP) and then tested with 355 nm nanosecond pulsed-lasers. Power spectral density (PSD) analysis shows that WDUP process eliminates the laser-detrimental spatial frequencies band of micro-waviness on SPDT machined surface and consequently decreases its modulation effect on the laser beams. The laser test results show that LIDT of WDUP machined crystal improves and its stability has a significant increase by 72.1% compared with that of SPDT. Moreover, a subsequent ultrasonic assisted solvent cleaning process is suggested to have a positive effect on the laser performance of machined KDP crystal. Damage crater investigation indicates that the damage morphologies exhibit highly thermal explosion features of melted cores and brittle fractures of periphery material, which can be described with the classic thermal explosion model. The comparison result demonstrates that damage mechanisms for SPDT and WDUP machined crystal are the same and WDUP process reveals the real bulk laser resistance of KDP optical crystal by removing the micro-waviness and subsurface damage on SPDT machined surface. This improvement of WDUP method makes the LIDT more accurate and will be beneficial to the laser performance of KDP crystal. PMID:29534032

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.

PubMed

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

Influence of substrate material and surface finishing on the morphology of the calcium-phosphate coating.

PubMed

Leitão, E; Barbosa, M A; de Groot, K

1997-07-01

The formation of an apatite-like layer was achieved by immersing Ti-6A1-4V, Ti-Al-2.5Fe, and 316 L stainless-steel substrata in Hank's balanced salt solution (HBSS). The layer was characterized by surface analysis techniques, namely X-ray microanalysis and X-ray diffraction, and the morphology was observed by scanning electron microscopy and atomic force microscopy. The concentrations of Ca and P were monitored as a function of time. The morphology of the precipitate layer seems to be dependent both on the type of metal substrate and its surface finish. Polished Ti-6A1-4V and Ti-Al-2.5Fe surfaces exhibit a plate precipitate morphology, whereas rougher surfaces show scattered crystal-like precipitation. The results suggest that the layer produced by immersion of polished titanium alloys in HBSS is constituted by an amorphous apatite.

Concentration data for anthropogenic organic compounds in ground water, surface water, and finished water of selected community water systems in the United States, 2002-05

USGS Publications Warehouse

Carter, Janet M.; Delzer, Gregory C.; Kingsbury, James A.; Hopple, Jessica A.

2007-01-01

The National Water-Quality Assessment Program of the U.S. Geological Survey began implementing Source Water-Quality Assessments (SWQAs) in 2001 that focus on characterizing the quality of source water and finished water of aquifers and major rivers used by some of the larger community water systems (CWSs) in the United States. As used for SWQA studies, source water is the raw (ambient) water collected at the supply well prior to water treatment (for ground water) or the raw (ambient) water collected from the river near the intake (for surface water), and finished water is the water that is treated and ready to be delivered to consumers. Finished water is collected before entering the distribution system. SWQA studies are conducted in two phases, and the objectives of SWQA studies are twofold: (1) to determine the occurrence and, for rivers, seasonal changes in concentrations of a broad list of anthropogenic organic compounds (AOCs) in aquifers and rivers that have some of the largest withdrawals for drinking-water supply (phase 1), and (2) for those AOCs found to occur most frequently in source water, characterize the extent to which these compounds are present in finished water (phase 2). These objectives were met for SWQA studies by collecting ground-water and surface-water (source) samples and analyzing these samples for 258 AOCs during phase 1. Samples from a subset of wells and surface-water sites located in areas with substantial agricultural production in the watershed were analyzed for 19 additional AOCs, for a total of 277 compounds analyzed for SWQA studies. The 277 compounds were classified according to the following 13 primary use or source groups: (1) disinfection by-products; (2) fumigant-related compounds; (3) fungicides; (4) gasoline hydrocarbons, oxygenates, and oxygenate degradates; (5) herbicides and herbicide degradates; (6) insecticides and insecticide degradates; (7) manufacturing additives; (8) organic synthesis compounds; (9) pavement- and

The Finish Line.

ERIC Educational Resources Information Center

Cohen, Andrew

1998-01-01

Details what is expected in a good floor finish for athletic facilities, and explores the different categories of finishes and their content within the context of environmental regulation and manufacturing standards. Also discusses urethane finishings, the debate over using waterbased finishes, and the influence of regulatory control that may…

Influence of the Cutting Conditions in the Surface Finishing of Turned Pieces of Titanium Alloys

NASA Astrophysics Data System (ADS)

Huerta, M.; Arroyo, P.; Sánchez Carrilero, M.; Álvarez, M.; Salguero, J.; Marcos, M.

2009-11-01

Titanium is a material that, despite its high cost, is increasingly being introduced in the aerospace industry due to both, its weight, its mechanical properties and its corrosion potential, very close to that of carbon fiber based composite material. This fact allows using Ti to form Fiber Metal Laminates Machining operations are usually used in the manufacturing processes of Ti based aerospace structural elements. These elements must be machined under high surface finish requirements. Previous works have shown the relationship between the surface roughness and the tool changes in the first instants of turning processes. From these results, new tests have been performed in an aeronautical factory, in order to analyse roughness in final pieces.

A novel approach of magnetorheological abrasive fluid finishing with swirling-assisted inlet flow

NASA Astrophysics Data System (ADS)

Kheradmand, Saeid; Esmailian, Mojtaba; Fatahy, A.

Abrasive flow machining has been the pioneer of new finishing processes. Rotating workpiece and imposing a magnetic field using magnetorheological working medium are some assisting manipulations to improve surface finishing, because they can increase the forces on the workpiece surface. Similarly, swirling the inlet flow using stationary swirler vanes, as a novel idea, may also increase forces on the surface, and then raise the material removal, with a lower expense and energy consumption compared with the case of workpiece rotation. Thus, in this paper, surface roughness improvement is studied in a pipe with rotating inlet flow of a magnetorheological finishing medium under imposing a magnetic field. The results are compared with the case of rotating workpiece, using 3D numerical simulation. The governing hydrodynamic parameters are investigated in both cases to monitor the flow variations. It is shown that surface roughness is improved by rotating inlet flow. However, it is found that finishing in the entrance length of swirling-assisted inlet flow can be so economical for short length workpieces, compared with the case of rotating workpiece, with very near Ra values. By comparison of the numerical results and published experimental data, current study also shows the ability of the numerical simulation, as an inexpensive and efficient tool, to predict the surface roughness changes in finishing processes.

Forces acting between polishing tool and workpiece surface in magnetorheological finishing

NASA Astrophysics Data System (ADS)

Schinhaerl, Markus; Vogt, Christian; Geiss, Andreas; Stamp, Richard; Sperber, Peter; Smith, Lyndon; Smith, Gordon; Rascher, Rolf

2008-08-01

Magnetorheological finishing is a computer-controlled polishing technique that is used mainly in the field of high-quality optical lens production. The process is based on the use of a magnetorheological polishing fluid that is able, in a reversible manner, to change its viscosity from a liquid state to a solid state under the control of a magnetic field. This outstanding characteristic facilitates rapid control (in milliseconds) of the yield stress, and thus the pressure applied to the workpiece surface to be polished. A three-axis dynamometer was used to measure the forces acting between the magnetorheological fluid and the workpiece surface during determination of the material removal characteristic of the polishing tool (influence function). The results of a testing series using a QED Q22-X MRF polishing machine with a 50 mm wheel assembly show that the normal forces range from about 2 to 20 N. Knowledge of the forces is essential, especially when thin workpieces are to be polished and distortion becomes significant. This paper discusses, and gives examples of, the variation in the parameters experienced during a programme of experiments, and provides examples of the value of this work.

Future ultra-speed tube-flight

NASA Astrophysics Data System (ADS)

Salter, Robert M.

1994-05-01

Future long-link, ultra-speed, surface transport systems will require electromagnetically (EM) driven and restrained vehicles operating under reduced-atmosphere in very straight tubes. Such tube-flight trains will be safe, energy conservative, pollution-free, and in a protected environment. Hypersonic (and even hyperballistic) speeds are theoretically achievable. Ultimate system choices will represent tradeoffs between amoritized capital costs (ACC) and operating costs. For example, long coasting links might employ aerodynamic lift coupled with EM restraint and drag make-up. Optimized, combined EM lift, and thrust vectors could reduce energy costs but at increased ACC. (Repulsive levitation can produce lift-over-drag l/d ratios a decade greater than aerodynamic), Alternatively, vehicle-emanated, induced-mirror fields in a conducting (aluminum sheet) road bed could reduce ACC but at substantial energy costs. Ultra-speed tube flight will demand fast-acting, high-precision sensors and computerized magnetic shimming. This same control system can maintain a magnetic 'guide way' invariant in inertial space with inertial detectors imbedded in tube structures to sense and correct for earth tremors. Ultra-speed tube flight can complete with aircraft for transit time and can provide even greater passenger convenience by single-model connections with local subways and feeder lines. Although cargo transport generally will not need to be performed at ultra speeds, such speeds may well be desirable for high throughput to optimize channel costs. Thus, a large and expensive pipeline might be replaced with small EM-driven pallets at high speeds.

Future ultra-speed tube-flight

NASA Technical Reports Server (NTRS)

Salter, Robert M.

1994-01-01

Future long-link, ultra-speed, surface transport systems will require electromagnetically (EM) driven and restrained vehicles operating under reduced-atmosphere in very straight tubes. Such tube-flight trains will be safe, energy conservative, pollution-free, and in a protected environment. Hypersonic (and even hyperballistic) speeds are theoretically achievable. Ultimate system choices will represent tradeoffs between amoritized capital costs (ACC) and operating costs. For example, long coasting links might employ aerodynamic lift coupled with EM restraint and drag make-up. Optimized, combined EM lift, and thrust vectors could reduce energy costs but at increased ACC. (Repulsive levitation can produce lift-over-drag l/d ratios a decade greater than aerodynamic), Alternatively, vehicle-emanated, induced-mirror fields in a conducting (aluminum sheet) road bed could reduce ACC but at substantial energy costs. Ultra-speed tube flight will demand fast-acting, high-precision sensors and computerized magnetic shimming. This same control system can maintain a magnetic 'guide way' invariant in inertial space with inertial detectors imbedded in tube structures to sense and correct for earth tremors. Ultra-speed tube flight can complete with aircraft for transit time and can provide even greater passenger convenience by single-model connections with local subways and feeder lines. Although cargo transport generally will not need to be performed at ultra speeds, such speeds may well be desirable for high throughput to optimize channel costs. Thus, a large and expensive pipeline might be replaced with small EM-driven pallets at high speeds.

Finishing of additively manufactured titanium alloy by shape adaptive grinding (SAG)

NASA Astrophysics Data System (ADS)

Beaucamp, Anthony T.; Namba, Yoshiharu; Charlton, Phillip; Jain, Samyak; Graziano, Arthur A.

2015-06-01

In recent years, rapid prototyping of titanium alloy components for medical and aeronautics application has become viable thanks to advances in technologies such as electron beam melting (EBM) and selective laser sintering (SLS). However, for many applications the high surface roughness generated by additive manufacturing techniques demands a post-finishing operation to improve the surface quality prior to usage. In this paper, the novel shape adaptive grinding process has been applied to finishing titanium alloy (Ti6Al4V) additively manufactured by EBM and SLS. It is shown that the micro-structured surface layer resulting from the melting process can be removed, and the surface can then be smoothed down to less than 10 nm Ra (starting from 4-5 μm Ra) using only three different diamond grit sizes. This paper also demonstrates application of the technology to freeform shapes, and documents the dimensional accuracy of finished artifacts.

Cryopreserved Ultra-Thick Human Amniotic Membrane for Conjunctival Surface Reconstruction After Excision of Conjunctival Tumors.

PubMed

Tanaka, Thais S; Demirci, Hakan

2016-04-01

Cryopreserved ultra-thick human amniotic membrane (AM) is used for glaucoma surgery. We evaluated the use of cryopreserved ultra-thick human AM for conjunctival surface reconstruction after excision of a conjunctival tumor. We retrospectively reviewed the medical records of 28 patients who underwent conjunctival surface reconstruction with cryopreserved ultra-thick human AM after excision of the tumor. The AM was secured to the surrounding conjunctiva and underlying sclera with interrupted 8-0 Vicryl sutures. Clinical data regarding demographics, diagnosis, size and location of conjunctival tumors, patient outcome, and complications were gathered. Of 28 patients, 6 (21.4%) had malignant melanoma, 4 (14.3%) had squamous cell carcinoma, 6 (21.4%) had conjunctival intraepithelial neoplasia, 1 (3.6%) had sebaceous carcinoma, 1 (3.6%) had mucoepidermoid carcinoma, 1 (3.6%) had conjunctival intraepithelial dysplasia, 5 (17.9%) had pterygium, 2 (7.1%) had compound nevus, 1 (3.6%) had a large epithelial inclusion cyst, and 1 (3.6%) patient had a granuloma. The mean area of graft size was 156 ± 120 mm2. Postoperatively, the graft was well tolerated with no failure, discomfort, or dehiscence. During the 17-month mean follow-up, symblepharon, which was clinically nonsignificant, developed in 3 (11%) patients and partial stem cell deficiency was noted in 5 (18%) patients. Cryopreserved ultra-thick human AM is a well-tolerated, effective graft material that is easy to handle. It is a viable alternative for conjunctival surface reconstruction after excision of a conjunctival tumor.

Automated Finishing with Autofinish

PubMed Central

Gordon, David; Desmarais, Cindy; Green, Phil

2001-01-01

Currently, the genome sequencing community is producing shotgun sequence data at a very high rate, but finishing (collecting additional directed sequence data to close gaps and improve the quality of the data) is not matching that rate. One reason for the difference is that shotgun sequencing is highly automated but finishing is not: Most finishing decisions, such as which directed reads to obtain and which specialized sequencing techniques to use, are made by people. If finishing rates are to increase to match shotgun sequencing rates, most finishing decisions also must be automated. The Autofinish computer program (which is part of the Consed computer software package) does this by automatically choosing finishing reads. Autofinish is able to suggest most finishing reads required for completion of each sequencing project, greatly reducing the amount of human attention needed. Autofinish sometimes completely finishes the project, with no human decisions required. It cannot solve the most complex problems, so we recommend that Autofinish be allowed to suggest reads for the first three rounds of finishing, and if the project still is not finished completely, a human finisher complete the work. We compared this Autofinish-Hybrid method of finishing against a human finisher in five different projects with a variety of shotgun depths by finishing each project twice—once with each method. This comparison shows that the Autofinish-Hybrid method saves many hours over a human finisher alone, while using roughly the same number and type of reads and closing gaps at roughly the same rate. Autofinish currently is in production use at several large sequencing centers. It is designed to be adaptable to the finishing strategy of the lab—it can finish using some or all of the following: resequencing reads, reverses, custom primer walks on either subclone templates or whole clone templates, PCR, or minilibraries. Autofinish has been used for finishing cDNA, genomic clones, and

Functional parameter screening for predicting durability of rolling sliding contacts with different surface finishes

NASA Astrophysics Data System (ADS)

Dimkovski, Z.; Lööf, P.-J.; Rosén, B.-G.; Nilsson, P. H.

2018-06-01

The reliability and lifetime of machine elements such as gears and rolling bearings depend on their wear and fatigue resistance. In order to screen the wear and surface damage, three finishing processes: (i) brushing, (ii) manganese phosphating and (iii) shot peening were applied on three disc pairs and long-term tested on a twin-disc tribometer. In this paper, the elastic contact of the disc surfaces (measured after only few revolutions) was simulated and a number of functional and roughness parameters were correlated. The functional parameters consisted of subsurface stresses at different depths and a new parameter called ‘pressure spikes’ factor’. The new parameter is derived from the pressure distribution and takes into account the proximity and magnitude of the pressure spikes. Strong correlations were found among the pressure spikes’ factor and surface peak/height parameters. The orthogonal shear stresses and Von Mises stresses at the shallowest depths under the surface have shown the highest correlations but no good correlations were found when the statistics of the whole stress fields was analyzed. The use of the new parameter offers a fast way to screen the durability of the contacting surfaces operating at similar conditions.

Three-Dimensional Planetary Surface Tracking Based on a Simple Ultra-Wideband Impulse-Radio Infrastructure

NASA Technical Reports Server (NTRS)

Barton, Richard J.; Ni, David; Ngo, Phong

2010-01-01

Several prototype ultra-wideband (UWB) impulse-radio (IR) tracking systems are currently under development at NASA Johnson Space Center (JSC). These systems are being studied for use in tracking of Lunar/Mars rovers and astronauts during early exploration missions when satellite navigation systems (such as GPS) are not available. To date, the systems that have been designed and tested are intended only for two-dimensional location and tracking, but these designs can all be extended to three-dimensional tracking with only minor modifications and increases in complexity. In this presentation, we will briefly review the design and performance of two of the current 2-D systems: one designed specifically for short-range, extremely high-precision tracking (approximately 1-2 cm resolution) and the other designed specifically for much longer range tracking with less stringent precision requirements (1-2 m resolution). We will then discuss a new multi-purpose system design based on a simple UWB-IR architecture that can be deployed easily on a planetary surface to support arbitrary three-dimensional localization and tracking applications. We will discuss utilization of this system as an infrastructure to provide both short-range and long-range tracking and analyze the localization performance of the system in several different configurations. We will give theoretical performance bounds for some canonical system configurations and compare these performance bounds with both numerical simulations of the system as well as actual experimental system performance evaluations.

Magnetorheological finishing: a perfect solution to nanofinishing requirements

NASA Astrophysics Data System (ADS)

Sidpara, Ajay

2014-09-01

Finishing of optics for different applications is the most important as well as difficult step to meet the specification of optics. Conventional grinding or other polishing processes are not able to reduce surface roughness beyond a certain limit due to high forces acting on the workpiece, embedded abrasive particles, limited control over process, etc. Magnetorheological finishing (MRF) process provides a new, efficient, and innovative way to finish optical materials as well many metals to their desired level of accuracy. This paper provides an overview of MRF process for different applications, important process parameters, requirement of magnetorheological fluid with respect to workpiece material, and some areas that need to be explored for extending the application of MRF process.

Concentration data for anthropogenic organic compounds in groundwater, surface water, and finished water of selected community water systems in the United States, 2002-10

USGS Publications Warehouse

Carter, Janet M.; Kingsbury, James A.; Hopple, Jessica A.; Delzer, Gregory C.

2010-01-01

The National Water-Quality Assessment Program of the U.S. Geological Survey began implementing Source Water-Quality Assessments (SWQAs) in 2001 that focus on characterizing the quality of source water and finished water of aquifers and major rivers used by some of the larger community water systems in the United States. As used in SWQA studies, source water is the raw (ambient) water collected at the supply well before water treatment (for groundwater) or the raw (ambient) water collected from the river near the intake (for surface water), and finished water is the water that has been treated and is ready to be delivered to consumers. Finished-water samples are collected before the water enters the distribution system. The primary objective of SWQAs is to determine the occurrence of more than 250 anthropogenic organic compounds in source water used by community water systems, many of which currently are unregulated in drinking water by the U.S. Environmental Protection Agency. A secondary objective is to understand recurrence patterns in source water and determine if these patterns also occur in finished water before distribution. SWQA studies were conducted in two phases for most studies completed by 2005, and in one phase for most studies completed since 2005. Analytical results are reported for a total of 295 different anthropogenic organic compounds monitored in source-water and finished-water samples collected during 2002-10. The 295 compounds were classified according to the following 13 primary use or source groups: (1) disinfection by-products; (2) fumigant-related compounds; (3) fungicides; (4) gasoline hydrocarbons, oxygenates, and oxygenate degradates; (5) herbicides and herbicide degradates; (6) insecticides and insecticide degradates; (7) manufacturing additives; (8) organic synthesis compounds; (9) pavement- and combustion-derived compounds; (10) personal-care and domestic-use products; (11) plant- or animal-derived biochemicals; (12) refrigerants and

Effects of Cr Content and Surface Finishes on Oxidation Behaviors of Austenitic Fe-Cr-Ni Alloys Exposed in Supercritical Water (SCW)

NASA Astrophysics Data System (ADS)

Xing, Bo

The scope of this work was to characterize the corrosion resistance of candidate austenitic alloys in supercritical water for the use of the fuel cladding material within the Canadian supercritical water-cooled reactor (SCWR) concept. A series of Commercial austenitic stainless steels (SS) and alloys were exposed to supercritical water for different exposure times up to 500 hours. Two surface finishes were applied - a coarse grinding with 120 grit abrasive or polishing with either 1200 grit or 0.05 microm alumina suspension. Gravimetric measurements and electron microscopy techniques were used to evaluate the oxidation behaviors of tested alloys. The superior corrosion resistance of alloy 310S was benefited from a critical Cr content of 25 wt.%. The surface finish played a significant role to vary the oxidation behavior of alloys containing slightly less than the critical Cr content. However, Oxide exfoliation was observed on low Cr content alloys.

Chronicle of 65 years of wood finishing research at the Forest Products Laboratory

Treesearch

Thomas M. Gorman; William C. Feist

1989-01-01

For 65 years, the Forest Products Laboratory (FPL) in Madison, Wisconsin, has had a continuous and extensive program of research on finishing wood for outdoor use. The research has stressed the fundamental aspects of wood weathering and the interactions of pretreatments and finishes on wood surfaces. This report outlines the history of the FPL wood finishing research...

A new seamless, smooth, interior, absorptive finishing system

NASA Astrophysics Data System (ADS)

D'Antonio, Peter

2003-10-01

Government architecture typically employs classic forms of vaults, domes and other focusing or reflective shapes, usually created with hard materials like concrete and plaster. The use of conventional porous absorption is typically rejected as an acoustical surface material for aesthetic reasons. Hence, many of these new and existing facilities have compromised speech intelligibility and music quality. Acousticians have sought a field-applied, absorptive finishing system that resembles a smooth plaster or painted drywall surface, since the dawn of architectural acoustics. Some success has been achieved using sprayed cellulose or cementitious materials, but surface smoothness has been a challenge. A new approach utilizing a thin microporous layer of mineral particles applied over a mineral wool panel will be described. This material can be applied to almost any shape surface, internally pigmented to match almost any color and renovated. Because of these unique characteristics the new seamless, absorptive, finishing system is being specified for many new and renovated spaces. Application examples will be presented.

Optimal Magnetorheological Fluid for Finishing of Chemical-Vapor-Deposited Zinc Sulfide

NASA Astrophysics Data System (ADS)

Salzman, Sivan

Magnetorheological finishing (MRF) of polycrystalline, chemical-vapor- deposited zinc sulfide (ZnS) optics leaves visible surface artifacts known as "pebbles". These artifacts are a direct result of the material's inner structure that consists of cone-like features that grow larger (up to a few millimeters in size) as deposition takes place, and manifest on the top deposited surface as "pebbles". Polishing the pebble features from a CVD ZnS substrate to a flat, smooth surface to below 10 nm root-mean-square is challenging, especially for a non-destructive polishing process such as MRF. This work explores ways to improve the surface finish of CVD ZnS processed with MRF through modification of the magnetorheological (MR) fluid's properties. A materials science approach is presented to define the anisotropy of CVD ZnS through a combination of chemical and mechanical experiments and theoretical predictions. Magnetorheological finishing experiments with single crystal samples of ZnS, whose cuts and orientations represent most of the facets known to occur in the polycrystalline CVD ZnS, were performed to explore the influence of material anisotropy on the material removal rate during MRF. By adjusting the fluid's viscosity, abrasive type concentration, and pH to find the chemo-mechanical conditions that equalize removal rates among all single crystal facets during MRF, we established an optimized, novel MR formulation to polish CVD ZnS without degrading the surface finish of the optic.

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

NASA Astrophysics Data System (ADS)

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

2015-12-01

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

Surface Cleaning Techniques: Ultra-Trace ICP-MS Sample Preparation and Assay of HDPE

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

Overman, Nicole R.; Hoppe, Eric W.; Addleman, Raymond S.

2013-06-01

The world’s most sensitive radiation detection and assay systems depend upon ultra-low background (ULB) materials to reduce unwanted radiological backgrounds. Herein, we evaluate methods to clean HDPE, a material of interest to ULB systems and the means to provide rapid assay of surface and bulk contamination. ULB level material and ultra-trace level detection of actinide elements is difficult to attain, due to the introduction of contamination from sample preparation equipment such as pipette tips, sample vials, forceps, etc. and airborne particulate. To date, literature available on the cleaning of such polymeric materials and equipment for ULB applications and ultra-trace analysesmore » is limited. For these reasons, a study has been performed to identify an effective way to remove surface contamination from polymers in an effort to provide improved instrumental detection limits. Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) was utilized to assess the effectiveness of a variety of leachate solutions for removal of inorganic uranium and thorium surface contamination from polymers, specifically high density polyethylene (HDPE). HDPE leaching procedures were tested to optimize contaminant removal of thorium and uranium. Calibration curves for thorium and uranium ranged from 15 ppq (fg/mL) to 1 ppt (pg/mL). Detection limits were calculated at 6 ppq for uranium and 7 ppq for thorium. Results showed the most effective leaching reagent to be clean 6 M nitric acid for 72 hour exposures. Contamination levels for uranium and thorium found in the leachate solutions were significant for ultralow level radiation detection applications.« less

Surface profiles and modulation of ultra-thin perfluoropolyether lubricant in contact sliding

NASA Astrophysics Data System (ADS)

Sinha, S. K.; Kawaguchi, M.; Kato, T.

2004-08-01

Deformation in shear and associated tribological behaviours of ultra-thin lubricants are of significant importance for the lubrication of magnetic hard disks and for other applications such as micro-electromechanical systems, nano-fluidics and nanotechnology. This paper presents the characteristics of the perfluoropolyether ultra-thin lubricant, in terms of its surface profiles when subjected to a contact sliding test. The results indicate that for a several-monolayers thick (~4.0-4.5 nm) lubricant film, sliding produces a considerable amount of surface roughness due to peaks of lubricant that persist during sliding; however, it can flow back or return to a smooth profile after a lapse of time when the sliding is stopped. For a monolayer-thin (~1.4-1.57 nm) film, the lubricant flow is restricted, and the rough profile created due to sliding persists and almost becomes permanent on the wear track. During sliding, due to high shear stress, a characteristic feature of lubricant profile modulation is observed. This modulation, or waviness, is due to the accumulation of lubricant in piles or islands, giving certain amplitudes and frequencies, which themselves depend upon the percentage of lubricant molecules that are chemically bonded to the substrate and the lubricant thickness. The results indicate that ultra-thin lubricants (monolayer and thicker) behave more like a semi-solid (having some sliding characteristics similar to those of rubbers) than a liquid when subjected to a high shear rate during contact sliding.

Study on Surface Roughness of Modified Silicon Carbide Mirrors polished by Magnetorheological Finishing

NASA Astrophysics Data System (ADS)

Du, Hang; Song, Ci; Li, Shengyi

2018-01-01

In order to obtain high precision and high surface quality silicon carbide mirrors, the silicon carbide mirror substrate is subjected to surface modification treatment. In this paper, the problem of Silicon Carbide (SiC) mirror surface roughness deterioration by MRF is studied. The reasons of surface flaws of “Comet tail” are analyzed. Influence principle of MRF polishing depth and the surface roughness of modified SiC mirrors is obtained by experiments. On this basis, the united process of modified SiC mirrors is proposed which is combined MRF with the small grinding head CCOS. The united process makes improvement in the surface accuracy and surface roughness of modified SiC mirrors.

CHEOPS: a space telescope for ultra-high precision photometry of exoplanet transits

NASA Astrophysics Data System (ADS)

Cessa, V.; Beck, T.; Benz, W.; Broeg, C.; Ehrenreich, D.; Fortier, A.; Peter, G.; Magrin, D.; Pagano, I.; Plesseria, J.-Y.; Steller, M.; Szoke, J.; Thomas, N.; Ragazzoni, R.; Wildi, F.

2017-11-01

The CHaracterising ExOPlanet Satellite (CHEOPS) is a joint ESA-Switzerland space mission dedicated to search for exoplanet transits by means of ultra-high precision photometry whose launch readiness is expected end 2017. The CHEOPS instrument will be the first space telescope dedicated to search for transits on bright stars already known to host planets. By being able to point at nearly any location on the sky, it will provide the unique capability of determining accurate radii for a subset of those planets for which the mass has already been estimated from ground-based spectroscopic surveys. CHEOPS will also provide precision radii for new planets discovered by the next generation ground-based transits surveys (Neptune-size and smaller). The main science goals of the CHEOPS mission will be to study the structure of exoplanets with radii typically ranging from 1 to 6 Earth radii orbiting bright stars. With an accurate knowledge of masses and radii for an unprecedented sample of planets, CHEOPS will set new constraints on the structure and hence on the formation and evolution of planets in this mass range. To reach its goals CHEOPS will measure photometric signals with a precision of 20 ppm in 6 hours of integration time for a 9th magnitude star. This corresponds to a signal to noise of 5 for a transit of an Earth-sized planet orbiting a solar-sized star (0.9 solar radii). This precision will be achieved by using a single frame-transfer backside illuminated CCD detector cool down at 233K and stabilized within {10 mK . The CHEOPS optical design is based on a Ritchey-Chretien style telescope with 300 mm effective aperture diameter, which provides a defocussed image of the target star while minimizing straylight using a dedicated field stop and baffle system. As CHEOPS will be in a LEO orbit, straylight suppression is a key point to allow the observation of faint stars. The telescope will be the only payload on a spacecraft platform providing pointing stability of < 8

Finishing/polishing of composite and compomer restoratives: effectiveness of one-step systems.

PubMed

Yap, Adrian U J; Yap, S H; Teo, C K; Ng, J J

2004-01-01

This study investigated the surface texture of composite (Z100, 3M ESPE) and compomer (F2000, 3M ESPE) restoratives after treatment with different one-step finishing/polishing systems (One-Gloss [OG], Shofu; PoGo [PG], Dentsply; Sof-Lex Brush [SB], 3M ESPE). The surface roughness obtained was compared to that using a matrix strip [MS], a two-step rubber abrasive (CompoSite [CS], Shofu) and a graded abrasive disk (Super Snap [SS], Shofu) system. Eight specimens (3-mm long x 3-mm wide x 2-mm deep) of each material were made according to manufacturer's instructions. With exception of the MS group, all groups were roughened with 320 grit grinding paper using a lapping device prior to finishing/polishing with the different systems. The mean surface roughness (microm) was measured with a profilometer. Data was subjected to ANOVA/Scheffe's tests and independent samples t-test at significance level 0.05. Mean Ra ranged from 0.22 to 0.32 microm for Z100 and 0.45 to 0.68 for F2000. For both materials, the smoothest surfaces were obtained with MS. The roughest surfaces were observed after treatment with SS and OG for Z100 and F2000, respectively. The effectiveness of the finishing/polishing systems was material dependent. The surface finish produced by PG and SB was superior or comparable to that obtained with CS, SS and OG.

The impact of feeding growing-finishing pigs with daily tailored diets using precision feeding techniques on animal performance, nutrient utilization, and body and carcass composition.

PubMed

Andretta, I; Pomar, C; Rivest, J; Pomar, J; Lovatto, P A; Radünz Neto, J

2014-09-01

The impact of moving from conventional to precision feeding systems in growing-finishing pig operations on animal performance, nutrient utilization, and body and carcass composition was studied. Fifteen animals per treatment for a total of 60 pigs of 41.2 (SE = 0.5) kg of BW were used in a performance trial (84 d) with 4 treatments: a 3-phase (3P) feeding program obtained by blending fixed proportions of feeds A (high nutrient density) and B (low nutrient density); a 3-phase commercial (COM) feeding program; and 2 daily-phase feeding programs in which the blended proportions of feeds A and B were adjusted daily to meet the estimated nutritional requirements of the group (multiphase-group feeding, MPG) or of each pig individually (multiphase-individual feeding, MPI). Daily feed intake was recorded each day and pigs were weighed weekly during the trial. Body composition was assessed at the beginning of the trial and every 28 d by dual-energy X-ray densitometry. Nitrogen and phosphorus excretion was estimated as the difference between retention and intake. Organ, carcass, and primal cut measurements were taken after slaughter. The COM feeding program reduced (P < 0.05) ADFI and improved G:F rate in relation to other treatments. The MPG and MPI programs showed values for ADFI, ADG, G:F, final BW, and nitrogen and phosphorus retention that were similar to those obtained for the 3P feeding program. However, compared with the 3P treatment, the MPI feeding program reduced the standardized ileal digestible lysine intake by 27%, the estimated nitrogen excretion by 22%, and the estimated phosphorus excretion by 27% (P < 0.05). Organs, carcass, and primal cut weights did not differ among treatments. Feeding growing-finishing pigs with daily tailored diets using precision feeding techniques is an effective approach to reduce nutrient excretion without compromising pig performance or carcass composition.

Guest Editorial Precision Surface Metrology

NASA Astrophysics Data System (ADS)

Wyant, James C.

1984-08-01

During the past two decades there have been many changes in precision surface metrology. The introduction of the laser and the large computer during the 1960s and 1970s produced many changes in testing capabilities and requirements. Several commercial interferometers became available in the 1970s, enabling people who were not necessarily experts in interferometry to use interferometers to produce better optics. Since both buyers and sellers could test optics, the quality of the optics manufactured and sold improved greatly. If a person ordered 1/10 wave optics, he would probably get 1/10 wave or better optics; if he got optics of lower quality, he would know it, and he could prove it and return it.

Advancements in non-contact metrology of asphere and diffractive optics

NASA Astrophysics Data System (ADS)

DeFisher, Scott

2017-11-01

Advancements in optical manufacturing technology allow optical designers to implement steep aspheric or high departure surfaces into their systems. Measuring these surfaces with profilometers or CMMs can be difficult due to large surface slopes or sharp steps in the surface. OptiPro has developed UltraSurf to qualify the form and figure of steep aspheric and diffractive optics. UltraSurf is a computer controlled, non-contact coordinate measuring machine. It incorporates five air-bearing axes, linear motors, high-resolution feedback, and a non-contact probe. The measuring probe is scanned over the optical surface while maintaining perpendicularity and a constant focal offset. Multiple probe technologies are available on UltraSurf. Each probe has strengths and weaknesses relative to the material properties, surface finish, and figure error of an optical component. The measuring probes utilize absolute distance to resolve step heights and diffractive surface patterns. The non-contact scanning method avoids common pitfalls with stylus contact instruments. Advancements in measuring speed and precision has enabled fast and accurate non-contact metrology of diffractive and steep aspheric surfaces. The benefits of data sampling with twodimensional profiles and three-dimensional topography maps will be presented. In addition, accuracy, repeatability, and machine qualification will be discussed with regards to aspheres and diffractive surfaces.

ANN Surface Roughness Optimization of AZ61 Magnesium Alloy Finish Turning: Minimum Machining Times at Prime Machining Costs

PubMed Central

Erdakov, Ivan Nikolaevich; Taha, Mohamed~Adel; Soliman, Mahmoud Sayed; El Rayes, Magdy Mostafa

2018-01-01

Magnesium alloys are widely used in aerospace vehicles and modern cars, due to their rapid machinability at high cutting speeds. A novel Edgeworth–Pareto optimization of an artificial neural network (ANN) is presented in this paper for surface roughness (Ra) prediction of one component in computer numerical control (CNC) turning over minimal machining time (Tm) and at prime machining costs (C). An ANN is built in the Matlab programming environment, based on a 4-12-3 multi-layer perceptron (MLP), to predict Ra, Tm, and C, in relation to cutting speed, vc, depth of cut, ap, and feed per revolution, fr. For the first time, a profile of an AZ61 alloy workpiece after finish turning is constructed using an ANN for the range of experimental values vc, ap, and fr. The global minimum length of a three-dimensional estimation vector was defined with the following coordinates: Ra = 0.087 μm, Tm = 0.358 min/cm3, C = $8.2973. Likewise, the corresponding finish-turning parameters were also estimated: cutting speed vc = 250 m/min, cutting depth ap = 1.0 mm, and feed per revolution fr = 0.08 mm/rev. The ANN model achieved a reliable prediction accuracy of ±1.35% for surface roughness. PMID:29772670

Breakdown Conditioning Chacteristics of Precision-Surface-Treatment-Electrode in Vacuum

NASA Astrophysics Data System (ADS)

Kato, Kastumi; Fukuoka, Yuji; Inagawa, Yukihiko; Saitoh, Hitoshi; Sakaki, Masayuki; Okubo, Hitoshi

Breakdown (BD) characteristics in vacuum are strongly dependent on the electrode surface condition, like the surface roughness etc. Therefore, in order to develop a high voltage vacuum circuit breaker, it is important to optimize the surface treatment process. This paper discusses about the effect of precision-surface-treatment of the electrode on breakdown conditioning characteristics under non-uniform electric field in vacuum. Experimental results reveal that the electrode surface treatment affects the conditioning process, especially the BD voltage and the BD field strength at the initial stage of the conditioning.

Studies on evaluating and removing subsurface damage on the ground surface of CLEARCERAM-Z HS

NASA Astrophysics Data System (ADS)

Akitaya, Hiroshi; Yamashita, Takuya; Ohshima, Norio; Iye, Masanori; Maihara, Toshinori; Tokoro, Hitoshi; Takahashi, Keisuke

2010-07-01

We evaluated depth of subsurface damage on a ground surface of the ultra low expansion glass-ceramics CLEARCERAMR®-Z HS (CC-Z HS) by Ohara Inc., which is one of the candidates for material for segmented mirrors of the Thirty Meter Telescope. We made polishing spots of Magnetorheological Finishing on the ground surface of CC-Z HS and measured exposed subsurface damage features on the spot surface. We also studied on hydrofluoric acid etching of the CC-Z HS ground surface, which is expected to be an effective method to remove a subsurface damage layer compared with time-consuming polishing. We etched small ground surfaces of CC-Z HS and evaluated its uniformity.

Achieving an ultra-narrow multiband light absorption meta-surface via coupling with an optical cavity.

PubMed

Liu, Zhengqi; Liu, Guiqiang; Liu, Xiaoshan; Huang, Shan; Wang, Yan; Pan, Pingping; Liu, Mulin

2015-06-12

Resonant plasmonic and metamaterial absorbers are of particular interest for applications in a wide variety of nanotechnologies including thermophotovoltaics, photothermal therapy, hot-electron collection and biosensing. However, it is rather challenging to realize ultra-narrow absorbers using plasmonic materials due to large optical losses in metals that inevitably decrease the quality of optical resonators. Here, we theoretically report methods to achieve an ultra-narrow light absorption meta-surface by using photonic modes of the optical cavities, which strongly couple with the plasmon resonances of the metallic nanostructures. Multispectral light absorption with absorption amplitude exceeding 99% and a bandwidth approaching 10 nm is achieved at the optical frequencies. Moreover, by introducing a thick dielectric coupling cavity, the number of absorption bands can be strongly increased and the bandwidth can even be narrowed to less than 5 nm due to the resonant spectrum splitting enabled by strong coupling between the plasmon resonances and the optical cavity modes. Designing such optical cavity-coupled meta-surface structures is a promising route for achieving ultra-narrow multiband absorbers, which can be used in absorption filters, narrow-band multispectral thermal emitters and thermophotovoltaics.

The improvement of laser induced damage resistance of optical workpiece surface by hydrodynamic effect polishing

NASA Astrophysics Data System (ADS)

Peng, Wenqiang; Guan, Chaoliang; Li, Shengyi; Wang, Zhuo

2016-10-01

Surface and subsurface damage in optical element will greatly decrease the laser induced damage threshold (LIDT) in the intense laser optical system. Processing damage on the workpiece surface can be inevitably caused when the material is removed in brittle or plastic mode. As a non-contact polishing technology, hydrodynamic effect polishing (HEP) shows very good performance on generating an ultra-smooth surface without damage. The material is removed by chemisorption between nanoparticle and workpiece surface in the elastic mode in HEP. The subsurface damage and surface scratches can be effectively removed after the polishing process. Meanwhile ultra-smooth surface with atomic level surface roughness can be achieved. To investigate the improvement of LIDT of optical workpiece, polishing experiment was conducted on a magnetorheological finishing (MRF) silica glass sample. AFM measurement results show that all the MRF directional plastic marks have been removed clearly and the root-mean-square (rms) surface roughness has decreased from 0.673nm to 0.177nm after HEP process. Laser induced damage experiment was conducted with laser pulse of 1064nm wavelength and 10ns time width. Compared with the original state, the LEDT of the silica glass sample polished by HEP has increased from 29.78J/cm2 to 45.47J/cm2. It demonstrates that LIDT of optical element treated by HEP can be greatly improved for ultra low surface roughness and nearly defect-free surface/subsurface.

[Assessment of precision and accuracy of digital surface photogrammetry with the DSP 400 system].

PubMed

Krimmel, M; Kluba, S; Dietz, K; Reinert, S

2005-03-01

The objective of the present study was to evaluate the precision and accuracy of facial anthropometric measurements obtained through digital 3-D surface photogrammetry with the DSP 400 system in comparison to traditional 2-D photogrammetry. Fifty plaster casts of cleft infants were imaged and 21 standard anthropometric measurements were obtained. For precision assessment the measurements were performed twice in a subsample. Accuracy was determined by comparison of direct measurements and indirect 2-D and 3-D image measurements. Precision of digital surface photogrammetry was almost as good as direct anthropometry and clearly better than 2-D photogrammetry. Measurements derived from 3-D images showed better congruence to direct measurements than from 2-D photos. Digital surface photogrammetry with the DSP 400 system is sufficiently precise and accurate for craniofacial anthropometric examinations.

Formation Mechanism of Finished Surface in Ultrahigh-Speed Grinding with cubic Boron Nitride (cBN) Wheels

NASA Astrophysics Data System (ADS)

Ichida, Yoshio; Sato, Ryunosuke; Morimoto, Yoshitaka; Ohsawa, Yoshiteru; Fredj, Nabil Ben

In this paper, we describe the formation mechanism of a finished surface in ultrahigh-speed grinding under a peripheral wheel speed higher than 200m/s. Grinding experiments using a grinding machine tool equipped with an active magnetic bearing spindle have been conducted over a range of grinding speeds from 60 to 300m/s. Moreover, grinding tests for producing some individual grooves using a grinding tool with multiple cBN grit have been carried out to clarify the effects of grinding speed on the side swelling formed along both sides of the grinding grooves. From the results of these experiments, we have confirmed that the roughness of the ground surface decreases with an increase in grinding speed, and this decrease is mainly due to the reduction of the swelling ratio with increasing grinding speed.

Ontological modelling of knowledge management for human-machine integrated design of ultra-precision grinding machine

NASA Astrophysics Data System (ADS)

Hong, Haibo; Yin, Yuehong; Chen, Xing

2016-11-01

Despite the rapid development of computer science and information technology, an efficient human-machine integrated enterprise information system for designing complex mechatronic products is still not fully accomplished, partly because of the inharmonious communication among collaborators. Therefore, one challenge in human-machine integration is how to establish an appropriate knowledge management (KM) model to support integration and sharing of heterogeneous product knowledge. Aiming at the diversity of design knowledge, this article proposes an ontology-based model to reach an unambiguous and normative representation of knowledge. First, an ontology-based human-machine integrated design framework is described, then corresponding ontologies and sub-ontologies are established according to different purposes and scopes. Second, a similarity calculation-based ontology integration method composed of ontology mapping and ontology merging is introduced. The ontology searching-based knowledge sharing method is then developed. Finally, a case of human-machine integrated design of a large ultra-precision grinding machine is used to demonstrate the effectiveness of the method.

Normal contour error measurement on-machine and compensation method for polishing complex surface by MRF

NASA Astrophysics Data System (ADS)

Chen, Hua; Chen, Jihong; Wang, Baorui; Zheng, Yongcheng

2016-10-01

The Magnetorheological finishing (MRF) process, based on the dwell time method with the constant normal spacing for flexible polishing, would bring out the normal contour error in the fine polishing complex surface such as aspheric surface. The normal contour error would change the ribbon's shape and removal characteristics of consistency for MRF. Based on continuously scanning the normal spacing between the workpiece and the finder by the laser range finder, the novel method was put forward to measure the normal contour errors while polishing complex surface on the machining track. The normal contour errors was measured dynamically, by which the workpiece's clamping precision, multi-axis machining NC program and the dynamic performance of the MRF machine were achieved for the verification and security check of the MRF process. The unit for measuring the normal contour errors of complex surface on-machine was designed. Based on the measurement unit's results as feedback to adjust the parameters of the feed forward control and the multi-axis machining, the optimized servo control method was presented to compensate the normal contour errors. The experiment for polishing 180mm × 180mm aspherical workpiece of fused silica by MRF was set up to validate the method. The results show that the normal contour error was controlled in less than 10um. And the PV value of the polished surface accuracy was improved from 0.95λ to 0.09λ under the conditions of the same process parameters. The technology in the paper has been being applied in the PKC600-Q1 MRF machine developed by the China Academe of Engineering Physics for engineering application since 2014. It is being used in the national huge optical engineering for processing the ultra-precision optical parts.

Neutral ion sources in precision manufacturing

NASA Technical Reports Server (NTRS)

Fawcett, Steven C.; Drueding, Thomas W.

1994-01-01

Ion figuring of optical components is a relatively new technology that can alleviate some of the problems associated with traditional contact polishing. Because the technique is non contacting, edge distortions and rib structure print through do not occur. This initial investigation was aimed at determining the effect of ion figuring on surface roughness of previously polished or ductile ground ceramic optical samples. This is the first step in research directed toward the combination of a pre-finishing process (ductile grinding or polishing) with ion figuring to produce finished ceramic mirrors. The second phase of the project is focusing on the development of mathematical algorithms that will deconvolve the ion beam profile from the surface figure errors so that these errors can be successfully removed from the optical components. In the initial phase of the project, multiple, chemical vapor deposited silicon carbide (CVD SiC) samples were polished or ductile ground to specular or near-specular roughness. These samples were then characterized to determine topographic surface information. The surface evaluation consisted of stylus profilometry, interferometry, and optical and scanning electron microscopy. The surfaces, were ion machined to depths from 0-5 microns. The finished surfaces were characterized to evaluate the effects of the ion machining process with respect to the previous processing methods and the pre-existing subsurface damage. The development of the control algorithms for figuring optical components has been completed. These algorithms have been validated with simulations and future experiments have been planned to verify the methods. This paper will present the results of the initial surface finish experiments and the control algorithms simulations.

Manufacturing Precise, Lightweight Paraboloidal Mirrors

NASA Technical Reports Server (NTRS)

Hermann, Frederick Thomas

2006-01-01

A process for fabricating a precise, diffraction- limited, ultra-lightweight, composite- material (matrix/fiber) paraboloidal telescope mirror has been devised. Unlike the traditional process of fabrication of heavier glass-based mirrors, this process involves a minimum of manual steps and subjective judgment. Instead, this process involves objectively controllable, repeatable steps; hence, this process is better suited for mass production. Other processes that have been investigated for fabrication of precise composite-material lightweight mirrors have resulted in print-through of fiber patterns onto reflecting surfaces, and have not provided adequate structural support for maintenance of stable, diffraction-limited surface figures. In contrast, this process does not result in print-through of the fiber pattern onto the reflecting surface and does provide a lightweight, rigid structure capable of maintaining a diffraction-limited surface figure in the face of changing temperature, humidity, and air pressure. The process consists mainly of the following steps: 1. A precise glass mandrel is fabricated by conventional optical grinding and polishing. 2. The mandrel is coated with a release agent and covered with layers of a carbon- fiber composite material. 3. The outer surface of the outer layer of the carbon-fiber composite material is coated with a surfactant chosen to provide for the proper flow of an epoxy resin to be applied subsequently. 4. The mandrel as thus covered is mounted on a temperature-controlled spin table. 5. The table is heated to a suitable temperature and spun at a suitable speed as the epoxy resin is poured onto the coated carbon-fiber composite material. 6. The surface figure of the optic is monitored and adjusted by use of traditional Ronchi, Focault, and interferometric optical measurement techniques while the speed of rotation and the temperature are adjusted to obtain the desired figure. The proper selection of surfactant, speed or rotation

Standard surface grinder for precision machining of thin-wall tubing

NASA Technical Reports Server (NTRS)

Jones, A.; Kotora, J., Jr.; Rein, J.; Smith, S. V.; Strack, D.; Stuckey, D.

1967-01-01

Standard surface grinder performs precision machining of thin-wall stainless steel tubing by electrical discharge grinding. A related adaptation, a traveling wire electrode fixture, is used for machining slots in thin-walled tubing.

Precision of working memory for visual motion sequences and transparent motion surfaces.

PubMed

Zokaei, Nahid; Gorgoraptis, Nikos; Bahrami, Bahador; Bays, Paul M; Husain, Masud

2011-12-01

Recent studies investigating working memory for location, color, and orientation support a dynamic resource model. We examined whether this might also apply to motion, using random dot kinematograms (RDKs) presented sequentially or simultaneously. Mean precision for motion direction declined as sequence length increased, with precision being lower for earlier RDKs. Two alternative models of working memory were compared specifically to distinguish between the contributions of different sources of error that corrupt memory (W. Zhang & S. J. Luck, 2008 vs. P. M. Bays, R. F. G. Catalao, & M. Husain, 2009). The latter provided a significantly better fit for the data, revealing that decrease in memory precision for earlier items is explained by an increase in interference from other items in a sequence rather than random guessing or a temporal decay of information. Misbinding feature attributes is an important source of error in working memory. Precision of memory for motion direction decreased when two RDKs were presented simultaneously as transparent surfaces, compared to sequential RDKs. However, precision was enhanced when one motion surface was prioritized, demonstrating that selective attention can improve recall precision. These results are consistent with a resource model that can be used as a general conceptual framework for understanding working memory across a range of visual features.

Precision of working memory for visual motion sequences and transparent motion surfaces

PubMed Central

Zokaei, Nahid; Gorgoraptis, Nikos; Bahrami, Bahador; Bays, Paul M; Husain, Masud

2012-01-01

Recent studies investigating working memory for location, colour and orientation support a dynamic resource model. We examined whether this might also apply to motion, using random dot kinematograms (RDKs) presented sequentially or simultaneously. Mean precision for motion direction declined as sequence length increased, with precision being lower for earlier RDKs. Two alternative models of working memory were compared specifically to distinguish between the contributions of different sources of error that corrupt memory (Zhang & Luck (2008) vs. Bays et al (2009)). The latter provided a significantly better fit for the data, revealing that decrease in memory precision for earlier items is explained by an increase in interference from other items in a sequence, rather than random guessing or a temporal decay of information. Misbinding feature attributes is an important source of error in working memory. Precision of memory for motion direction decreased when two RDKs were presented simultaneously as transparent surfaces, compared to sequential RDKs. However, precision was enhanced when one motion surface was prioritized, demonstrating that selective attention can improve recall precision. These results are consistent with a resource model that can be used as a general conceptual framework for understanding working memory across a range of visual features. PMID:22135378

Ultra-broadband and efficient surface plasmon polariton launching through metallic nanoslits of subwavelength period

PubMed Central

Li, Guangyuan; Zhang, Jiasen

2014-01-01

Ultra-broadband, efficient and unidirectional surface plasmon polariton (SPP) launching is of great concern in plasmonic devices and circuits. To address this challenge, a novel method adopting deep-subwavelength slits of subwavelength period (λSPP/4 ~ λSPP/3) in a thick metal film and under backside illumination is proposed. A new band pattern featuring broadband and wide angular characteristics, which is due to the coupling of the zeroth-order SPP resonance at the superstrate–metal interface and the first-order SPP resonance at the metal–substrate interface, is observed for the first time in the dispersion diagram. Unidirectional SPP launching efficiency of ~50%, ultra-broad bandwidth of up to 780 nm, covering the entire optical fiber communication bands, and relatively wide angular range of 7° are achieved. This remarkable efficient, ultra-broadband and wide angular performance is demonstrated by carefully designed experiments in the near infrared regime, showing good agreement with numerical results. PMID:25081812

Ultra-broadband and efficient surface plasmon polariton launching through metallic nanoslits of subwavelength period.

PubMed

Li, Guangyuan; Zhang, Jiasen

2014-08-01

Ultra-broadband, efficient and unidirectional surface plasmon polariton (SPP) launching is of great concern in plasmonic devices and circuits. To address this challenge, a novel method adopting deep-subwavelength slits of subwavelength period (λSPP/4 ~ λSPP/3) in a thick metal film and under backside illumination is proposed. A new band pattern featuring broadband and wide angular characteristics, which is due to the coupling of the zeroth-order SPP resonance at the superstrate-metal interface and the first-order SPP resonance at the metal-substrate interface, is observed for the first time in the dispersion diagram. Unidirectional SPP launching efficiency of ~50%, ultra-broad bandwidth of up to 780 nm, covering the entire optical fiber communication bands, and relatively wide angular range of 7° are achieved. This remarkable efficient, ultra-broadband and wide angular performance is demonstrated by carefully designed experiments in the near infrared regime, showing good agreement with numerical results.

Assessment of the influence of surface finishing and weld joints on the corrosion/oxidation behaviour of stainless steels in lead bismuth eutectic

NASA Astrophysics Data System (ADS)

Martín-Muñoz, F. J.; Soler-Crespo, L.; Gómez-Briceño, D.

2011-09-01

The objective of this paper is to gain some insight into the influence of the surface finishing in the oxidation/corrosion behaviour of 316L and T91 steels in lead bismuth eutectic (LBE). Specimens of both materials with different surface states were prepared (as-received, grinded, grinded and polished, and electrolitically polished) and oxidation tests were carried out at 775 and 825 K from 100 to 2000 h for two different oxygen concentrations and for H 2/H 2O molar ratios of 3 and 0.03. The general conclusion for these tests is that the effect of surface finishing on the corrosion/protection processes is not significant under the tested conditions. In addition the behaviour of weld joints, T91-T91 Tungsten Inert Gas (TIG) and T91-316L have been also studied under similar conditions. The conclusions are that, whereas T91-T91 welded joint shows the same corrosion properties as the parent materials for the conditions tested, AISI 316L-T91 welded joint, present an important dissolution over seam area that it associated to the electrode 309S used for the fabrication process.

ANN Surface Roughness Optimization of AZ61 Magnesium Alloy Finish Turning: Minimum Machining Times at Prime Machining Costs.

PubMed

Abbas, Adel Taha; Pimenov, Danil Yurievich; Erdakov, Ivan Nikolaevich; Taha, Mohamed Adel; Soliman, Mahmoud Sayed; El Rayes, Magdy Mostafa

2018-05-16

Magnesium alloys are widely used in aerospace vehicles and modern cars, due to their rapid machinability at high cutting speeds. A novel Edgeworth⁻Pareto optimization of an artificial neural network (ANN) is presented in this paper for surface roughness ( Ra ) prediction of one component in computer numerical control (CNC) turning over minimal machining time ( T m ) and at prime machining costs ( C ). An ANN is built in the Matlab programming environment, based on a 4-12-3 multi-layer perceptron (MLP), to predict Ra , T m , and C , in relation to cutting speed, v c , depth of cut, a p , and feed per revolution, f r . For the first time, a profile of an AZ61 alloy workpiece after finish turning is constructed using an ANN for the range of experimental values v c , a p , and f r . The global minimum length of a three-dimensional estimation vector was defined with the following coordinates: Ra = 0.087 μm, T m = 0.358 min/cm³, C = $8.2973. Likewise, the corresponding finish-turning parameters were also estimated: cutting speed v c = 250 m/min, cutting depth a p = 1.0 mm, and feed per revolution f r = 0.08 mm/rev. The ANN model achieved a reliable prediction accuracy of ±1.35% for surface roughness.

Effects of surface finishing conditions on the biocompatibility of a nickel-chromium dental casting alloy.

PubMed

McGinley, Emma Louise; Coleman, David C; Moran, Gary P; Fleming, Garry J P

2011-07-01

To assess the effects of surface finishing condition (polished or alumina particle air abraded) on the biocompatibility of direct and indirect exposure to a nickel-chromium (Ni-Cr) d.Sign®10 dental casting alloy on oral keratinocytes. Biocompatibility was performed by assessing cellular viability and morphology, metabolic activity, cellular toxicity and presence of inflammatory cytokine markers. Discs of d.Sign®10 were cast, alumina particle air abraded and half were polished before surface roughness was determined by profilometry. Biocompatibility was assessed by placing the discs directly or indirectly (with immersion solutions) into contact with TR146 monolayers. Metal ion release was determined by ICP-MS. Cell viability was assessed by trypan blue dye exclusion, metabolic activity by XTT and cellular toxicity by LDH. Inflammatory cytokine analysis was performed using sandwich ELISAs. The mean polished Ra value was significantly reduced (P<0.001) compared with the alumina particle air abraded discs but metal ion release was significantly increased for the polished discs. Significant reductions in cell density of polished compared with alumina particle air abraded discs was observed following direct or indirect exposure. A significant reduction in metabolic activity, increase in cellular toxicity and an increase in the presence of inflammatory cytokine markers was highlighted for the polished relative to the alumina particle air abraded discs at 24h. Finishing condition of the Ni-Cr dental alloy investigated has important clinical implications. The approach of employing cell density and morphology, metabolic activity, cellular toxicity levels and inflammatory marker responses to TR146 epithelial cells combined with ICP-MS afforded the authors an increased insight into the complex processes dental alloys undergo in the oral environment. Copyright © 2011 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Surface Preparation Methods to Enhance Dynamic Surface Property Measurements of Shocked Metal Surfaces

NASA Astrophysics Data System (ADS)

Zellner, Michael; McNeil, Wendy; Gray, George, III; Huerta, David; King, Nicholas; Neal, George; Payton, Jeremy; Rubin, Jim; Stevens, Gerald; Turley, William; Buttler, William

2008-03-01

This effort investigates surface-preparation methods to enhance dynamic surface-property measurements of shocked metal surfaces. To assess the ability of making reliable and consistent dynamic surface-property measurements, the amount of material ejected from the free-surface upon shock release to vacuum (ejecta) was monitored for shocked Al-1100 and Sn targets. Four surface preparation methods were considered: fly-cut machined finish, diamond-turned machine finish, polished finish, and ball-rolled. The samples were shock loaded by in-contact detonation of HE PBX-9501 on the front-side of the metal coupons. Ejecta production at the back-side or free-side of the metal coupons was monitored using piezoelectric pins, optical shadowgraphy, and x-ray attenuation radiography.

Surface preparation methods to enhance dynamic surface property measurements of shocked metal surfaces

NASA Astrophysics Data System (ADS)

Zellner, M. B.; Vogan McNeil, W.; Gray, G. T.; Huerta, D. C.; King, N. S. P.; Neal, G. E.; Valentine, S. J.; Payton, J. R.; Rubin, J.; Stevens, G. D.; Turley, W. D.; Buttler, W. T.

2008-04-01

This effort investigates surface-preparation methods to enhance dynamic surface-property measurements of shocked metal surfaces. To assess the ability of making reliable and consistent dynamic surface-property measurements, the amount of material ejected from the free surface upon shock release to vacuum (ejecta) was monitored for shocked Al-1100 and Sn targets. Four surface-preparation methods were considered: Fly-cut machine finish, diamond-turned machine finish, polished finish, and ball rolled. The samples were shock loaded by in-contact detonation of HE PBX-9501 on the front side of the metal coupons. Ejecta production at the back side or free side of the metal coupons was monitored using piezoelectric pins, optical shadowgraphy, and x-ray attenuation radiography.

Different Techniques For Producing Precision Holes (>20 mm) In Hardened Steel—Comparative Results

NASA Astrophysics Data System (ADS)

Coelho, R. T.; Tanikawa, S. T.

2009-11-01

High speed machining (HSM), or high performance machining, has been one of the most recent technological advances. When applied to milling operations, using adequate machines, CAM programs and tooling, it allows cutting hardened steels, which was not feasible just a couple of years ago. The use of very stiff and precision machines has created the possibilities of machining holes in hardened steels, such as AISI H13 with 48-50 HRC, using helical interpolations, for example. Such process is particularly useful for holes with diameter bigger than normal solid carbide drills commercially available, around 20 mm, or higher. Such holes may need narrow tolerances, fine surface finishing, which can be obtained just by end milling operations. The present work compares some of the strategies used to obtain such holes by end milling, and also some techniques employed to finish them, by milling, boring and also by fine grinding at the same machine. Results indicate that it is possible to obtain holes with less than 0.36 m in circularity, 7.41 m in cylindricity and 0.12 m in surface roughness Ra. Additionally, there is less possibilities of obtaining heat affected layers when using such technique.

Theoretical and experimental research on machine tool servo system for ultra-precision position compensation on CNC lathe

NASA Astrophysics Data System (ADS)

Ma, Zhichao; Hu, Leilei; Zhao, Hongwei; Wu, Boda; Peng, Zhenxing; Zhou, Xiaoqin; Zhang, Hongguo; Zhu, Shuai; Xing, Lifeng; Hu, Huang

2010-08-01

The theories and techniques for improving machining accuracy via position control of diamond tool's tip and raising resolution of cutting depth on precise CNC lathes have been extremely focused on. A new piezo-driven ultra-precision machine tool servo system is designed and tested to improve manufacturing accuracy of workpiece. The mathematical model of machine tool servo system is established and the finite element analysis is carried out on parallel plate flexure hinges. The output position of diamond tool's tip driven by the machine tool servo system is tested via a contact capacitive displacement sensor. Proportional, integral, derivative (PID) feedback is also implemented to accommodate and compensate dynamical change owing cutting forces as well as the inherent non-linearity factors of the piezoelectric stack during cutting process. By closed loop feedback controlling strategy, the tracking error is limited to 0.8 μm. Experimental results have shown the proposed machine tool servo system could provide a tool positioning resolution of 12 nm, which is much accurate than the inherent CNC resolution magnitude. The stepped shaft of aluminum specimen with a step increment of cutting depth of 1 μm is tested, and the obtained contour illustrates the displacement command output from controller is accurately and real-time reflected on the machined part.

Phase transition temperatures of 405-725 K in superfluid ultra-dense hydrogen clusters on metal surfaces

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

Holmlid, Leif, E-mail: holmlid@chem.gu.se; Kotzias, Bernhard

Ultra-dense hydrogen H(0) with its typical H-H bond distance of 2.3 pm is superfluid at room temperature as expected for quantum fluids. It also shows a Meissner effect at room temperature, which indicates that a transition point to a non-superfluid state should exist above room temperature. This transition point is given by a disappearance of the superfluid long-chain clusters H{sub 2N}(0). This transition point is now measured for several metal carrier surfaces at 405 - 725 K, using both ultra-dense protium p(0) and deuterium D(0). Clusters of ordinary Rydberg matter H(l) as well as small symmetric clusters H{sub 4}(0) andmore » H{sub 3}(0) (which do not give a superfluid or superconductive phase) all still exist on the surface at high temperature. This shows directly that desorption or diffusion processes do not remove the long superfluid H{sub 2N}(0) clusters. The two ultra-dense forms p(0) and D(0) have different transition temperatures under otherwise identical conditions. The transition point for p(0) is higher in temperature, which is unexpected.« less

Evaluation of Some Finishing Properties of Oil Palm Particleboard for Furniture Application

NASA Astrophysics Data System (ADS)

Ratnasingam, J.; Nyugen, V.; Ioras, F.

The finishing properties of particleboard made from the Empty-Fruit Bunch (EFB) of oil palm (Elaeis guineensis Jacq.) were evaluated for its suitability for furniture applications, using different coating and overlay materials. The results found that the thick plastic-formica overlay provided the best surface finish, in terms of surface smoothness, adhesion strength and impact resistance. Although the polyurethane lacquer provided an acceptable finish, its quality and performance is not comparable to that of the thick plastic overlay. Despite the fact that the use of such overlay material may render the material not aesthetically appealing and limit it to concealed applications or where the thick overlay material is tolerated, its cost competitiveness and environmental friendliness may be able to position the oil palm particleboard as a substitute for the conventional wood-based particleboard in the furniture manufacturing industry.

Suppression of surface segregation of the phosphorous δ-doping layer by insertion of an ultra-thin silicon layer for ultra-shallow Ohmic contacts on n-type germanium

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

Yamada, Michihiro; Uematsu, Masashi; Itoh, Kohei M., E-mail: kitoh@appi.keio.ac.jp

2015-09-28

We demonstrate the formation of abrupt phosphorus (P) δ-doping profiles in germanium (Ge) by the insertion of ultra-thin silicon (Si) layers. The Si layers at the δ-doping region significantly suppress the surface segregation of P during the molecular beam epitaxial growth of Ge and high-concentration active P donors are confined within a few nm of the initial doping position. The current-voltage characteristics of the P δ-doped layers with Si insertion show excellent Ohmic behaviors with low enough resistivity for ultra-shallow Ohmic contacts on n-type Ge.

Surface Acoustic Wave Monitor for Deposition and Analysis of Ultra-Thin Films

NASA Technical Reports Server (NTRS)

Hines, Jacqueline H. (Inventor)

2015-01-01

A surface acoustic wave (SAW) based thin film deposition monitor device and system for monitoring the deposition of ultra-thin films and nanomaterials and the analysis thereof is characterized by acoustic wave device embodiments that include differential delay line device designs, and which can optionally have integral reference devices fabricated on the same substrate as the sensing device, or on a separate device in thermal contact with the film monitoring/analysis device, in order to provide inherently temperature compensated measurements. These deposition monitor and analysis devices can include inherent temperature compensation, higher sensitivity to surface interactions than quartz crystal microbalance (QCM) devices, and the ability to operate at extreme temperatures.

Development of hybrid fluid jet/float polishing process

NASA Astrophysics Data System (ADS)

Beaucamp, Anthony T. H.; Namba, Yoshiharu; Freeman, Richard R.

2013-09-01

On one hand, the "float polishing" process consists of a tin lap having many concentric grooves, cut from a flat by single point diamond turning. This lap is rotated above a hydrostatic bearing spindle of high rigidity, damping and rotational accuracy. The optical surface thus floats above a thin layer of abrasive particles. But whilst surface texture can be smoothed to ~0.1nm rms (as measured by atomic force microscopy), this process can only be used on flat surfaces. On the other hand, the CNC "fluid jet polishing" process consists of pumping a mixture of water and abrasive particles to a converging nozzle, thus generating a polishing spot that can be moved along a tool path with tight track spacing. But whilst tool path feed can be moderated to ultra-precisely correct form error on freeform optical surfaces, surface finish improvement is generally limited to ~1.5nm rms (with fine abrasives). This paper reports on the development of a novel finishing method, that combines the advantages of "fluid jet polishing" (i.e. freeform corrective capability) with "float polishing" (i.e. super-smooth surface finish of 0.1nm rms or less). To come up with this new "hybrid" method, computational fluid dynamic modeling of both processes in COMSOL is being used to characterize abrasion conditions and adapt the process parameters of experimental fluid jet polishing equipment, including: (1) geometrical shape of nozzle, (2) position relative to the surface, (3) control of inlet pressure. This new process is aimed at finishing of next generation X-Ray / Gamma Ray focusing optics.

Polishability of thin electrolytic and electroless NiP layers

NASA Astrophysics Data System (ADS)

Kinast, Jan; Beier, Matthias; Gebhardt, Andreas; Risse, Stefan; Tünnermann, Andreas

2015-10-01

Ultra-precise metal optics are key components of sophisticated scientific instrumentation in astronomy and space applications, covering a wide spectral range. Especially for applications in the visible or ultra-violet spectral ranges, a low roughness of the optics is required. Therefore, a polishable surface is necessary. State of the art is an amorphous nickel-phosphorus (NiP) layer, which enables several polishing techniques achieving a roughness of <1 nm RMS. Typically, these layers are approximately 30 μm to 60 μm thick. Deposited on Al6061, the bimetallic effect leads to a restricted operational temperature, caused by different coefficients of thermal expansion of Al6061 and NiP. Thinner NiP layers reduce the bimetallic effect. Hence, the possible operating temperature range. A deterministic shape correction via Magnetorheological Finishing of the substrate Al6061 leads to low shape deviations prior to the NiP deposition. This allows for depositing thin NiP-layers, which are polishable via a chemical mechanical polishing technique aiming at ultra-precise metal optics. The present article shows deposition processes and polishability of electroless and electrolytic NiP layers with thicknesses between 1 μm and 10 μm.

Ultra-wide-field imaging in diabetic retinopathy; an overview.

PubMed

Ghasemi Falavarjani, Khalil; Wang, Kang; Khadamy, Joobin; Sadda, Srinivas R

2016-06-01

To present an overview on ultra-wide-field imaging in diabetic retinopathy. A comprehensive search of the pubmed database was performed using the search terms of "ultra-wide-field imaging", "ultra-wide-field fluorescein angiography" and "diabetic retinopathy". The relevant original articles were reviewed. New advances in ultra-wide-field imaging allow for precise measurements of the peripheral retinal lesions. A consistent finding amongst these articles was that ultra-wide-field imaging improved detection of peripheral lesion. There was discordance among the studies, however, on the correlation between peripheral diabetic lesions and diabetic macular edema. Visualization of the peripheral retina using ultra-wide-field imaging improves diagnosis and classification of diabetic retinopathy. Additional studies are needed to better define the association of peripheral diabetic lesions with diabetic macular edema.

Subsurface damage in precision ground ULE(R) and Zerodur(R) surfaces.

PubMed

Tonnellier, X; Morantz, P; Shore, P; Baldwin, A; Evans, R; Walker, D D

2007-09-17

The total process cycle time for large ULE((R)) and Zerodur((R))optics can be improved using a precise and rapid grinding process, with low levels of surface waviness and subsurface damage. In this paper, the amounts of defects beneath ULE((R)) and Zerodur((R) )surfaces ground using a selected grinding mode were compared. The grinding response was characterised by measuring: surface roughness, surface profile and subsurface damage. The observed subsurface damage can be separated into two distinct depth zones, which are: 'process' and 'machine dynamics' related.

Flame retardant finishing of cotton fabric based on synergistic compounds containing boron and nitrogen.

PubMed

Xie, Kongliang; Gao, Aiqin; Zhang, Yongsheng

2013-10-15

Boric acid and compound containing nitrogen, 2,4,6-tri[(2-hydroxy-3-trimethyl-ammonium)propyl]-1,3,5-triazine chloride (Tri-HTAC) were used to finish cotton fabric. The flame retardant properties of the finished cotton fabrics and the synergetic effects of boron and nitrogen elements were investigated and evaluated by limited oxygen index (LOI) method. The mechanism of cross-linking reaction among cotton fiber, Tri-HTAC, and boric acid was discussed by FTIR and element analysis. The thermal stability and surface morphology of the finished cotton fabrics were investigated by thermogravimetric analysis (TGA) and scanning electron microscope (SEM), respectively. The finishing system of the mixture containing boron and nitrogen showed excellent synergistic flame retardancy for cotton fabric. The cotton fabric finished with mixture system had excellent flame retardancy. The LOI value of the treated cotton fabric increased over 27.5. Tri-HTAC could form covalent bonds with cellulose fiber and boric acid. The flame retardant cotton fabric showed a slight decrease in tensile strength and whiteness. The surface morphology of flame retardant cotton fiber was smooth. Copyright © 2013 Elsevier Ltd. All rights reserved.

A method for Removing Surface Contamination on Ultra-pure Copper Spectrometer Components

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

Hoppe, Eric W.; Seifert, Allen; Aalseth, Craig E.

Spectrometers for the lowest-level radiometric measurements require materials of extreme radiopurity. Measurements of rare nuclear decays, e.g. neutrinoless double-beta decay, can require construction and shielding materials with bulk radiopurity reaching one micro-Becquerel per kilogram or less. When such extreme material purity is achieved, surface contamination, particularly solid daughters in the natural radon decay chains, can become the limiting background. High-purity copper is an important material for ultra-low-background spectrometers and thus is the focus of this work. A method for removing surface contamination at very low levels without attacking the bulk material is described. An assay method using a low-background proportionalmore » counter made of the material under examination is employed, and the resulting preliminary result of achievable surface contamination levels is presented.« less

Combined fabrication technique for high-precision aspheric optical windows

NASA Astrophysics Data System (ADS)

Hu, Hao; Song, Ci; Xie, Xuhui

2016-07-01

Specifications made on optical components are becoming more and more stringent with the performance improvement of modern optical systems. These strict requirements not only involve low spatial frequency surface accuracy, mid-and-high spatial frequency surface errors, but also surface smoothness and so on. This presentation mainly focuses on the fabrication process for square aspheric window which combines accurate grinding, magnetorheological finishing (MRF) and smoothing polishing (SP). In order to remove the low spatial frequency surface errors and subsurface defects after accurate grinding, the deterministic polishing method MRF with high convergence and stable material removal rate is applied. Then the SP technology with pseudo-random path is adopted to eliminate the mid-and-high spatial frequency surface ripples and high slope errors which is the defect for MRF. Additionally, the coordinate measurement method and interferometry are combined in different phase. Acid-etched method and ion beam figuring (IBF) are also investigated on observing and reducing the subsurface defects. Actual fabrication result indicates that the combined fabrication technique can lead to high machining efficiency on manufaturing the high-precision and high-quality optical aspheric windows.

Ultra-broadband unidirectional launching of surface plasmon polaritons by a double-slit structure beyond the diffraction limit.

PubMed

Chen, Jianjun; Sun, Chengwei; Li, Hongyun; Gong, Qihuang

2014-11-21

Surface-plasmon-polariton (SPP) launchers, which can couple the free space light to the SPPs on the metal surface, are among the key elements for the plasmonic devices and nano-photonic systems. Downscaling the SPP launchers below the diffraction limit and directly delivering the SPPs to the desired subwavelength plasmonic waveguides are of importance for high-integration plasmonic circuits. By designing a submicron double-slit structure with different slit widths, an ultra-broadband (>330 nm) unidirectional SPP launcher is realized theoretically and experimentally based on the different phase delays of SPPs propagating along the metal surface and the near-field interfering effect. More importantly, the broadband and unidirectional properties of the SPP launcher are still maintained when the slit length is reduced to a subwavelength scale. This can make the launcher occupy only a very small area of <λ(2)/10 on the metal surface. Such a robust unidirectional SPP launcher beyond the diffraction limit can be directly coupled to a subwavelength plasmonic waveguide efficiently, leading to an ultra-tight SPP source, especially as a subwavelength localized guided SPP source.

A real-time surface inspection system for precision steel balls based on machine vision

NASA Astrophysics Data System (ADS)

Chen, Yi-Ji; Tsai, Jhy-Cherng; Hsu, Ya-Chen

2016-07-01

Precision steel balls are one of the most fundament components for motion and power transmission parts and they are widely used in industrial machinery and the automotive industry. As precision balls are crucial for the quality of these products, there is an urgent need to develop a fast and robust system for inspecting defects of precision steel balls. In this paper, a real-time system for inspecting surface defects of precision steel balls is developed based on machine vision. The developed system integrates a dual-lighting system, an unfolding mechanism and inspection algorithms for real-time signal processing and defect detection. The developed system is tested under feeding speeds of 4 pcs s-1 with a detection rate of 99.94% and an error rate of 0.10%. The minimum detectable surface flaw area is 0.01 mm2, which meets the requirement for inspecting ISO grade 100 precision steel balls.

Precision production: enabling deterministic throughput for precision aspheres with MRF

NASA Astrophysics Data System (ADS)

Maloney, Chris; Entezarian, Navid; Dumas, Paul

2017-10-01

Aspherical lenses offer advantages over spherical optics by improving image quality or reducing the number of elements necessary in an optical system. Aspheres are no longer being used exclusively by high-end optical systems but are now replacing spherical optics in many applications. The need for a method of production-manufacturing of precision aspheres has emerged and is part of the reason that the optics industry is shifting away from artisan-based techniques towards more deterministic methods. Not only does Magnetorheological Finishing (MRF) empower deterministic figure correction for the most demanding aspheres but it also enables deterministic and efficient throughput for series production of aspheres. The Q-flex MRF platform is designed to support batch production in a simple and user friendly manner. Thorlabs routinely utilizes the advancements of this platform and has provided results from using MRF to finish a batch of aspheres as a case study. We have developed an analysis notebook to evaluate necessary specifications for implementing quality control metrics. MRF brings confidence to optical manufacturing by ensuring high throughput for batch processing of aspheres.

Potential Energy Surface Database of Group II Dimer

National Institute of Standards and Technology Data Gateway

SRD 143 NIST Potential Energy Surface Database of Group II Dimer (Web, free access)   This database provides critical atomic and molecular data needed in order to evaluate the feasibility of using laser cooled and trapped Group II atomic species (Mg, Ca, Sr, and Ba) for ultra-precise optical clocks or quantum information processing devices.

Micro-optical fabrication by ultraprecision diamond machining and precision molding

NASA Astrophysics Data System (ADS)

Li, Hui; Li, Likai; Naples, Neil J.; Roblee, Jeffrey W.; Yi, Allen Y.

2017-06-01

Ultraprecision diamond machining and high volume molding for affordable high precision high performance optical elements are becoming a viable process in optical industry for low cost high quality microoptical component manufacturing. In this process, first high precision microoptical molds are fabricated using ultraprecision single point diamond machining followed by high volume production methods such as compression or injection molding. In the last two decades, there have been steady improvements in ultraprecision machine design and performance, particularly with the introduction of both slow tool and fast tool servo. Today optical molds, including freeform surfaces and microlens arrays, are routinely diamond machined to final finish without post machining polishing. For consumers, compression molding or injection molding provide efficient and high quality optics at extremely low cost. In this paper, first ultraprecision machine design and machining processes such as slow tool and fast too servo are described then both compression molding and injection molding of polymer optics are discussed. To implement precision optical manufacturing by molding, numerical modeling can be included in the future as a critical part of the manufacturing process to ensure high product quality.

High-precision Non-Contact Measurement of Creep of Ultra-High Temperature Materials for Aerospace

NASA Technical Reports Server (NTRS)

Rogers, Jan R.; Hyers, Robert

2008-01-01

For high-temperature applications (greater than 2,000 C) such as solid rocket motors, hypersonic aircraft, nuclear electric/thermal propulsion for spacecraft, and more efficient jet engines, creep becomes one of the most important design factors to be considered. Conventional creep-testing methods, where the specimen and test apparatus are in contact with each other, are limited to temperatures approximately 1,700 C. Development of alloys for higher-temperature applications is limited by the availability of testing methods at temperatures above 2000 C. Development of alloys for applications requiring a long service life at temperatures as low as 1500 C, such as the next generation of jet turbine superalloys, is limited by the difficulty of accelerated testing at temperatures above 1700 C. For these reasons, a new, non-contact creep-measurement technique is needed for higher temperature applications. A new non-contact method for creep measurements of ultra-high-temperature metals and ceramics has been developed and validated. Using the electrostatic levitation (ESL) facility at NASA Marshall Space Flight Center, a spherical sample is rotated quickly enough to cause creep deformation due to centrifugal acceleration. Very accurate measurement of the deformed shape through digital image analysis allows the stress exponent n to be determined very precisely from a single test, rather than from numerous conventional tests. Validation tests on single-crystal niobium spheres showed excellent agreement with conventional tests at 1985 C; however the non-contact method provides much greater precision while using only about 40 milligrams of material. This method is being applied to materials including metals and ceramics for non-eroding throats in solid rockets and next-generation superalloys for turbine engines. Recent advances in the method and the current state of these new measurements will be presented.

Ultra-precision fabrication of 500 mm long and laterally graded Ru/C multilayer mirrors for X-ray light sources.

PubMed

Störmer, M; Gabrisch, H; Horstmann, C; Heidorn, U; Hertlein, F; Wiesmann, J; Siewert, F; Rack, A

2016-05-01

X-ray mirrors are needed for beam shaping and monochromatization at advanced research light sources, for instance, free-electron lasers and synchrotron sources. Such mirrors consist of a substrate and a coating. The shape accuracy of the substrate and the layer precision of the coating are the crucial parameters that determine the beam properties required for various applications. In principal, the selection of the layer materials determines the mirror reflectivity. A single layer mirror offers high reflectivity in the range of total external reflection, whereas the reflectivity is reduced considerably above the critical angle. A periodic multilayer can enhance the reflectivity at higher angles due to Bragg reflection. Here, the selection of a suitable combination of layer materials is essential to achieve a high flux at distinct photon energies, which is often required for applications such as microtomography, diffraction, or protein crystallography. This contribution presents the current development of a Ru/C multilayer mirror prepared by magnetron sputtering with a sputtering facility that was designed in-house at the Helmholtz-Zentrum Geesthacht. The deposition conditions were optimized in order to achieve ultra-high precision and high flux in future mirrors. Input for the improved deposition parameters came from investigations by transmission electron microscopy. The X-ray optical properties were investigated by means of X-ray reflectometry using Cu- and Mo-radiation. The change of the multilayer d-spacing over the mirror dimensions and the variation of the Bragg angles were determined. The results demonstrate the ability to precisely control the variation in thickness over the whole mirror length of 500 mm thus achieving picometer-precision in the meter-range.

Ultra-precision fabrication of 500 mm long and laterally graded Ru/C multilayer mirrors for X-ray light sources

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

Störmer, M., E-mail: michael.stoermer@hzg.de; Gabrisch, H.; Horstmann, C.

2016-05-15

X-ray mirrors are needed for beam shaping and monochromatization at advanced research light sources, for instance, free-electron lasers and synchrotron sources. Such mirrors consist of a substrate and a coating. The shape accuracy of the substrate and the layer precision of the coating are the crucial parameters that determine the beam properties required for various applications. In principal, the selection of the layer materials determines the mirror reflectivity. A single layer mirror offers high reflectivity in the range of total external reflection, whereas the reflectivity is reduced considerably above the critical angle. A periodic multilayer can enhance the reflectivity atmore » higher angles due to Bragg reflection. Here, the selection of a suitable combination of layer materials is essential to achieve a high flux at distinct photon energies, which is often required for applications such as microtomography, diffraction, or protein crystallography. This contribution presents the current development of a Ru/C multilayer mirror prepared by magnetron sputtering with a sputtering facility that was designed in-house at the Helmholtz-Zentrum Geesthacht. The deposition conditions were optimized in order to achieve ultra-high precision and high flux in future mirrors. Input for the improved deposition parameters came from investigations by transmission electron microscopy. The X-ray optical properties were investigated by means of X-ray reflectometry using Cu- and Mo-radiation. The change of the multilayer d-spacing over the mirror dimensions and the variation of the Bragg angles were determined. The results demonstrate the ability to precisely control the variation in thickness over the whole mirror length of 500 mm thus achieving picometer-precision in the meter-range.« less

Evaluate error correction ability of magnetorheological finishing by smoothing spectral function

NASA Astrophysics Data System (ADS)

Wang, Jia; Fan, Bin; Wan, Yongjian; Shi, Chunyan; Zhuo, Bin

2014-08-01

Power Spectral Density (PSD) has been entrenched in optics design and manufacturing as a characterization of mid-high spatial frequency (MHSF) errors. Smoothing Spectral Function (SSF) is a newly proposed parameter that based on PSD to evaluate error correction ability of computer controlled optical surfacing (CCOS) technologies. As a typical deterministic and sub-aperture finishing technology based on CCOS, magnetorheological finishing (MRF) leads to MHSF errors inevitably. SSF is employed to research different spatial frequency error correction ability of MRF process. The surface figures and PSD curves of work-piece machined by MRF are presented. By calculating SSF curve, the correction ability of MRF for different spatial frequency errors will be indicated as a normalized numerical value.

Quantification of microscopic surface features of single point diamond turned optics with subsequent chemical polishing

NASA Astrophysics Data System (ADS)

Cardenas, Nelson; Kyrish, Matthew; Taylor, Daniel; Fraelich, Margaret; Lechuga, Oscar; Claytor, Richard; Claytor, Nelson

2015-03-01

Electro-Chemical Polishing is routinely used in the anodizing industry to achieve specular surface finishes of various metals products prior to anodizing. Electro-Chemical polishing functions by leveling the microscopic peaks and valleys of the substrate, thereby increasing specularity and reducing light scattering. The rate of attack is dependent of the physical characteristics (height, depth, and width) of the microscopic structures that constitute the surface finish. To prepare the sample, mechanical polishing such as buffing or grinding is typically required before etching. This type of mechanical polishing produces random microscopic structures at varying depths and widths, thus the electropolishing parameters are determined in an ad hoc basis. Alternatively, single point diamond turning offers excellent repeatability and highly specific control of substrate polishing parameters. While polishing, the diamond tool leaves behind an associated tool mark, which is related to the diamond tool geometry and machining parameters. Machine parameters such as tool cutting depth, speed and step over can be changed in situ, thus providing control of the spatial frequency of the microscopic structures characteristic of the surface topography of the substrate. By combining single point diamond turning with subsequent electro-chemical etching, ultra smooth polishing of both rotationally symmetric and free form mirrors and molds is possible. Additionally, machining parameters can be set to optimize post polishing for increased surface quality and reduced processing times. In this work, we present a study of substrate surface finish based on diamond turning tool mark spatial frequency with subsequent electro-chemical polishing.

Carcass quality and meat tenderness of Hawaii pasture-finished cattle and Hawaii-originated, mainland feedlot-finished cattle.

PubMed

Kim, Yong Soo; Fukumoto, Glen Kazumi; Kim, Sunae

2012-10-01

The objective of this study was to compare the carcass quality and meat tenderness of Hawaii cattle finished on subtropical pasture with those of mainland US feedlot-finished cattle that were shipped from Hawaii after weaning. Rib-eye steak samples were collected from 30 feedlot-finished cattle harvested at a slaughter house in Washington State, USA and from 13 subtropical pasture-finished cattle harvested at a local slaughter house in Hawaii, then shipped to meat science laboratory at the University of Hawaii, Manoa. Samples were aged for 2 weeks at 4°C and frozen for later proximate analysis and meat tenderness measurement. Feedlot-finished cattle had significantly heavier carcass weight (353 vs 290 kg) and thicker backfat (13.5 vs 6.6 mm), but no significant difference was observed in rib-eye area between the two groups. Marbling score (Small) and United States Department of Agriculture quality grade (Choice) of the pasture-finished beef were not significantly (P < 0.05) different from those of feedlot-finished beef. The shear force value of pasture-finished beef (5.18 kg) was not statistically different (P < 0.05) from that of feedlot-finished beef (4.40 kg). In conclusion, results of this study suggest that Hawaii cattle finished on subtropical pasture produced as tender beef as mainland feedlot-finished cattle with less intramuscular fat.

Ultra-low fouling and high antibody loading zwitterionic hydrogel coatings for sensing and detection in complex media.

PubMed

Chou, Ying-Nien; Sun, Fang; Hung, Hsiang-Chieh; Jain, Priyesh; Sinclair, Andrew; Zhang, Peng; Bai, Tao; Chang, Yung; Wen, Ten-Chin; Yu, Qiuming; Jiang, Shaoyi

2016-08-01

For surface-based diagnostic devices to achieve reliable biomarker detection in complex media such as blood, preventing nonspecific protein adsorption and incorporating high loading of biorecognition elements are paramount. In this work, a novel method to produce nonfouling zwitterionic hydrogel coatings was developed to achieve these goals. Poly(carboxybetaine acrylamide) (pCBAA) hydrogel thin films (CBHTFs) prepared with a carboxybetaine diacrylamide crosslinker (CBAAX) were coated on gold and silicon dioxide surfaces via a simple spin coating process. The thickness of CBHTFs could be precisely controlled between 15 and 150nm by varying the crosslinker concentration, and the films demonstrated excellent long-term stability. Protein adsorption from undiluted human blood serum onto the CBHTFs was measured with surface plasmon resonance (SPR). Hydrogel thin films greater than 20nm exhibited ultra-low fouling (<5ng/cm(2)). In addition, the CBHTFs were capable of high antibody functionalization for specific biomarker detection without compromising their nonfouling performance. This strategy provides a facile method to modify SPR biosensor chips with an advanced nonfouling material, and can be potentially expanded to a variety of implantable medical devices and diagnostic biosensors. In this work, we developed an approach to realize ultra-low fouling and high ligand loading with a highly-crosslinked, purely zwitterionic, carboxybetaine thin film hydrogel (CBHTF) coating platform. The CBHTF on a hydrophilic surface demonstrated long-term stability. By varying the crosslinker content in the spin-coated hydrogel solution, the thickness of CBHTFs could be precisely controlled. Optimized CBHTFs exhibited ultra-low nonspecific protein adsorption below 5ng/cm(2) measured by a surface plasmon resonance (SPR) sensor, and their 3D architecture allowed antibody loading to reach 693ng/cm(2). This strategy provides a facile method to modify SPR biosensor chips with an advanced

The MESSIER surveyor: unveiling the ultra-low surface brightness universe

NASA Astrophysics Data System (ADS)

Valls-Gabaud, David; MESSIER Collaboration

2017-03-01

The MESSIER surveyor is a small mission designed at exploring the very low surface brightness universe. The satellite will drift-scan the entire sky in 6 filters covering the 200-1000 nm range, reaching unprecedented surface brightness levels of 34 and 37 mag arcsec-2 in the optical and UV, respectively. These levels are required to achieve the two main science goals of the mission: to critically test the ΛCDM paradigm of structure formation through (1) the detection and characterisation of ultra-faint dwarf galaxies, which are predicted to be extremely abundant around normal galaxies, but which remain elusive; and (2) tracing the cosmic web, which feeds dark matter and baryons into galactic haloes, and which may contain the reservoir of missing baryons at low redshifts. A large number of science cases, ranging from stellar mass loss episodes to intracluster light through fluctuations in the cosmological UV-optical background radiation are free by-products of the full-sky maps produced.

Experimental and theoretical analysis of defocused CO2 laser microchanneling on PMMA for enhanced surface finish

NASA Astrophysics Data System (ADS)

Prakash, Shashi; Kumar, Subrata

2017-02-01

The poor surface finish of CO2 laser-micromachined microchannel walls is a major limitation of its utilization despite several key advantages, like low fabrication cost and low time consumption. Defocused CO2 laser beam machining is an effective solution for fabricating smooth microchannel walls on polymer and glass substrates. In this research work, the CO2 laser microchanneling process on PMMA has been analyzed at different beam defocus positions. Defocused processing has been investigated both theoretically and experimentally, and the depth of focus and beam diameter have been determined experimentally. The effect of beam defocusing on the microchannel width, depth, surface roughness, heat affected zone and microchannel profile were examined. A previously developed analytical model for microchannel depth prediction has been improved by incorporating the threshold energy density factor. A semi-analytical model for predicting the microchannel width at different defocus positions has been developed. A semi-empirical model has also been developed for predicting microchannel widths at different defocusing conditions for lower depth values. The developed models were compared and verified by performing actual experiments. Multi-objective optimization was performed to select the best optimum set of input parameters for achieving the desired surface roughness.

Research of polishing process to control the iron contamination on the magnetorheological finished KDP crystal surface.

PubMed

Chen, Shaoshan; Li, Shengyi; Peng, Xiaoqiang; Hu, Hao; Tie, Guipeng

2015-02-20

A new nonaqueous and abrasive-free magnetorheological finishing (MRF) method is adopted for processing a KDP crystal. MRF polishing is easy to result in the embedding of carbonyl iron (CI) powders; meanwhile, Fe contamination on the KDP crystal surface will affect the laser induced damage threshold seriously. This paper puts forward an appropriate MRF polishing process to avoid the embedding. Polishing results show that the embedding of CI powders can be avoided by controlling the polishing parameters. Furthermore, on the KDP crystal surface, magnetorheological fluids residua inevitably exist after polishing and in which the Fe contamination cannot be removed completely by initial ultrasonic cleaning. To solve this problem, a kind of ion beam figuring (IBF) polishing is introduced to remove the impurity layer. Then the content of Fe element contamination and the depth of impurity elements are measured by time of flight secondary ion mass spectrometry. The measurement results show that there are no CI powders embedding in the MRF polished surface and no Fe contamination after the IBF polishing process, respectively. That verifies the feasibility of MRF polishing-IBF polishing (cleaning) for processing a KDP crystal.

AstroImageJ: Image Processing and Photometric Extraction for Ultra-precise Astronomical Light Curves

NASA Astrophysics Data System (ADS)

Collins, Karen A.; Kielkopf, John F.; Stassun, Keivan G.; Hessman, Frederic V.

2017-02-01

ImageJ is a graphical user interface (GUI) driven, public domain, Java-based, software package for general image processing traditionally used mainly in life sciences fields. The image processing capabilities of ImageJ are useful and extendable to other scientific fields. Here we present AstroImageJ (AIJ), which provides an astronomy specific image display environment and tools for astronomy specific image calibration and data reduction. Although AIJ maintains the general purpose image processing capabilities of ImageJ, AIJ is streamlined for time-series differential photometry, light curve detrending and fitting, and light curve plotting, especially for applications requiring ultra-precise light curves (e.g., exoplanet transits). AIJ reads and writes standard Flexible Image Transport System (FITS) files, as well as other common image formats, provides FITS header viewing and editing, and is World Coordinate System aware, including an automated interface to the astrometry.net web portal for plate solving images. AIJ provides research grade image calibration and analysis tools with a GUI driven approach, and easily installed cross-platform compatibility. It enables new users, even at the level of undergraduate student, high school student, or amateur astronomer, to quickly start processing, modeling, and plotting astronomical image data with one tightly integrated software package.

Sex Difference in Draft-Legal Ultra-Distance Events - A Comparison between Ultra-Swimming and Ultra-Cycling.

PubMed

Salihu, Lejla; Rüst, Christoph Alexander; Rosemann, Thomas; Knechtle, Beat

2016-04-30

Recent studies reported that the sex difference in performance in ultra-endurance sports such as swimming and cycling changed over the years. However, the aspect of drafting in draft-legal ultra-endurance races has not yet been investigated. This study investigates the sex difference in ultra-swimming and ultra-cycling draft-legal races where drafting - swimming or cycling behind other participants to save energy and have more power at the end of the race to overtake them, is allowed. The change in performance of the annual best and the annual three best in an ultra-endurance swimming race (16-km 'Faros Swim Marathon') over 38 years and in a 24-h ultra-cycling race ('World Cycling Race') over 13 years were compared and analysed with respect to sex difference. Furthermore, performances of the fastest female and male finishers ever were compared. In the swimming event, the sex difference of the annual best male and female decreased non-significantly (P = 0.262) from 5.3% (1976) to 1.0% (2013). The sex gap of speed in the annual three fastest swimmers decreased significantly (P = 0.043) from 5.9 ± 1.6% (1979) to 4.7 ± 3.1% (2013). In the cycling event, the difference in cycling speed between the annual best male and female decreased significantly (P = 0.026) from 33.31% (1999) to 10.89% (2011). The sex gap of speed in the annual three fastest decreased significantly (P = 0.001) from 32.9 ± 0.6% (1999) to 16.4 ± 5.9% (2011). The fastest male swimmer ever (swimming speed 5.3 km/h, race time: 03:01:55 h:min:s) was 1.5% faster than the fastest female swimmer (swimming speed 5.2 km/h, race time: 03:04:09 h:min:s). The three fastest male swimmers ever (mean 5.27 ± 0.13 km/h) were 4.4% faster than the three fastest female swimmers (mean 5.05 ± 0.20 km/h) (P < 0.05). In the cycling event, the best male ever (cycling speed 45.8 km/h) was 26.4% faster than the best female (cycling speed 36.1 km/h). The three fastest male cyclists ever (45.9 km/h) (mean 45.85 ± 0.05 km

A three dimensional scaffold with precise micro-architecture and surface micro-textures

PubMed Central

Mata, Alvaro; Kim, Eun Jung; Boehm, Cynthia A.; Fleischman, Aaron J.; Muschler, George F.; Roy, Shuvo

2013-01-01

A three-dimensional (3D) structure comprising precisely defined microarchitecture and surface micro-textures, designed to present specific physical cues to cells and tissues, may provide an efficient scaffold in a variety of tissue engineering and regenerative medicine applications. We report a fabrication technique based on microfabrication and soft lithography that permits for the development of 3D scaffolds with both precisely engineered architecture and tailored surface topography. The scaffold fabrication technique consists of three key steps starting with microfabrication of a mold using an epoxy-based photoresist (SU-8), followed by dual-sided molding of a single layer of polydimethylsiloxane (PDMS) using a mechanical jig for precise motion control; and finally, alignment, stacking, and adhesion of multiple PDMS layers to achieve a 3D structure. This technique was used to produce 3D Texture and 3D Smooth PDMS scaffolds, where the surface topography comprised 10 μm-diameter/height posts and smooth surfaces, respectively. The potential utility of the 3D microfabricated scaffolds, and the role of surface topography, were subsequently investigated in vitro with a combined heterogeneous population of adult human stem cells and their resultant progenitor cells, collectively termed connective tissue progenitors (CTPs), under conditions promoting the osteoblastic phenotype. Examination of bone-marrow derived CTPs cultured on the 3D Texture scaffold for 9 days revealed cell growth in three dimensions and increased cell numbers compared to those on the 3D Smooth scaffold. Furthermore, expression of alkaline phosphatase mRNA was higher on the 3D Texture scaffold, while osteocalcin mRNA expression was comparable for both types of scaffolds. PMID:19524292

A Surface-Coupled Optical Trap with 1-bp Precision via Active Stabilization

PubMed Central

Okoniewski, Stephen R.; Carter, Ashley R.; Perkins, Thomas T.

2017-01-01

Optical traps can measure bead motions with Å-scale precision. However, using this level of precision to infer 1-bp motion of molecular motors along DNA is difficult, since a variety of noise sources degrade instrumental stability. In this chapter, we detail how to improve instrumental stability by (i) minimizing laser pointing, mode, polarization, and intensity noise using an acousto-optical-modulator mediated feedback loop and (ii) minimizing sample motion relative to the optical trap using a 3-axis piezo-electric-stage mediated feedback loop. These active techniques play a critical role in achieving a surface stability of 1 Å in 3D over tens of seconds and a 1-bp stability and precision in a surface-coupled optical trap over a broad bandwidth (Δf = 0.03–2 Hz) at low force (6 pN). These active stabilization techniques can also aid other biophysical assays that would benefit from improved laser stability and/or Å-scale sample stability, such as atomic force microscopy and super-resolution imaging. PMID:27844426

A Surface-Coupled Optical Trap with 1-bp Precision via Active Stabilization.

PubMed

Okoniewski, Stephen R; Carter, Ashley R; Perkins, Thomas T

2017-01-01

Optical traps can measure bead motions with Å-scale precision. However, using this level of precision to infer 1-bp motion of molecular motors along DNA is difficult, since a variety of noise sources degrade instrumental stability. In this chapter, we detail how to improve instrumental stability by (1) minimizing laser pointing, mode, polarization, and intensity noise using an acousto-optical-modulator mediated feedback loop and (2) minimizing sample motion relative to the optical trap using a three-axis piezo-electric-stage mediated feedback loop. These active techniques play a critical role in achieving a surface stability of 1 Å in 3D over tens of seconds and a 1-bp stability and precision in a surface-coupled optical trap over a broad bandwidth (Δf = 0.03-2 Hz) at low force (6 pN). These active stabilization techniques can also aid other biophysical assays that would benefit from improved laser stability and/or Å-scale sample stability, such as atomic force microscopy and super-resolution imaging.

Weighing Ultra-Cool Stars

NASA Astrophysics Data System (ADS)

2004-05-01

Large Ground-Based Telescopes and Hubble Team-Up to Perform First Direct Brown Dwarf Mass Measurement [1] Summary Using ESO's Very Large Telescope at Paranal and a suite of ground- and space-based telescopes in a four-year long study, an international team of astronomers has measured for the first time the mass of an ultra-cool star and its companion brown dwarf. The two stars form a binary system and orbit each other in about 10 years. The team obtained high-resolution near-infrared images; on the ground, they defeated the blurring effect of the terrestrial atmosphere by means of adaptive optics techniques. By precisely determining the orbit projected on the sky, the astronomers were able to measure the total mass of the stars. Additional data and comparison with stellar models then yield the mass of each of the components. The heavier of the two stars has a mass around 8.5% of the mass of the Sun and its brown dwarf companion is even lighter, only 6% of the solar mass. Both objects are relatively young with an age of about 500-1,000 million years. These observations represent a decisive step towards the still missing calibration of stellar evolution models for very-low mass stars. PR Photo 19a/04: Orbit of the ultra-cool stars in 2MASSW J0746425+2000321. PR Photo 19b/04: Animated Gif of the orbital motion. Telephone number star Even though astronomers have found several hundreds of very low mass stars and brown dwarfs, the fundamental properties of these extreme objects, such as masses and surface temperatures, are still not well known. Within the cosmic zoo, these ultra-cool stars represent a class of "intermediate" objects between giant planets - like Jupiter - and "normal" stars less massive than our Sun, and to understand them well is therefore crucial to the field of stellar astrophysics. The problem with these ultra-cool stars is that contrary to normal stars that burn hydrogen in their central core, no unique relation exists between the luminosity of the

Finishing Techniques for Silicon Nitride Bearings

DTIC Science & Technology

1976-03-01

finishing procedures. Rolling contact fatigue lives of silicon nitride with selected smoother finishes tested at 800 ksi Hertz stress were an order...grinding. Rolling contact fatigue lives of silicon nitride with selected smoother finishes tested at 800 ksi Hertz stress were an order of magnitude...lives of silicon nitride with selected smoother finishes tested at 800 ksi Hertz stress were an order of magnitude longer than those

Development and ultra-structure of an ultra-thin silicone epidermis of bioengineered alternative tissue.

PubMed

Wessels, Quenton; Pretorius, Etheresia

2015-08-01

Burn wound care today has a primary objective of temporary or permanent wound closure. Commercially available engineered alternative tissues have become a valuable adjunct to the treatment of burn injuries. Their constituents can be biological, alloplastic or a combination of both. Here the authors describe the aspects of the development of a siloxane epidermis for a collagen-glycosaminoglycan and for nylon-based artificial skin replacement products. A method to fabricate an ultra-thin epidermal equivalent is described. Pores, to allow the escape of wound exudate, were punched and a tri-filament nylon mesh or collagen scaffold was imbedded and silicone polymerisation followed at 120°C for 5 minutes. The ultra-structure of these bilaminates was assessed through scanning electron microscopy. An ultra-thin biomedical grade siloxane film was reliably created through precision coating on a pre-treated polyethylene terephthalate carrier. © 2013 The Authors. International Wound Journal © 2013 Medicalhelplines.com Inc and John Wiley & Sons Ltd.

Precision Machining Application and Technology: An Overview and Perspective.

DTIC Science & Technology

1983-08-24

diamond turning lathes are being used to produce computer discs. Bryant Symons, an English firm, has reported diamond turning an aluminum computer disk at...34 Precision Engineering, Vol. 5(2), Guildford, Engl nd, July 1983. Watt, G., " Lathe for Generation of Spherical -arfaces of Revolution," given to Optical...Precision CNC Diamond Turning Machine," Annuals of the CIRP, Vol. 31/1, p 409, 1982. 8. Bryant Simmons Product Brochur-, "Ultra Precision Oiamond Turning

Surface plasmon enhanced SWIR absorption at the ultra n-doped substrate/PbSe nanostructure layer interface

NASA Astrophysics Data System (ADS)

Wittenberg, Vladimir; Rosenblit, Michael; Sarusi, Gabby

2017-08-01

This work presents simulation results of the plasmon enhanced absorption that can be achieved in the short wavelength infrared (SWIR - 1200 nm to 1800 nm) spectral range at the interface between ultra-heavily doped substrates and a PbSe nanostructure non-epitaxial growth absorbing layer. The absorption enhancement simulated in this study is due to surface plasmon polariton (SPP) excitation at the interface between these ultra-heavily n-doped GaAs or GaN substrates, which are nearly semimetals to SWIR light, and an absorption layer made of PbSe nano-spheres or nano-columns. The ultra-heavily doped GaAs or GaN substrates are simulated as examples, based on the Drude-Lorentz permittivity model. In the simulation, the substrates and the absorption layer were patterned jointly to forma blazed lattice, and then were back-illuminated using SWIR with a central wavelength of 1500 nm. The maximal field enhancement achieved was 17.4 with a penetration depth of 40 nm. Thus, such architecture of an ultra-heavily doped semiconductor and infrared absorbing layer can further increase the absorption due to the plasmonic enhanced absorption effect in the SWIR spectral band without the need to use a metallic layer as in the case of visible light.

Computer numeric control generation of toric surfaces

NASA Astrophysics Data System (ADS)

Bradley, Norman D.; Ball, Gary A.; Keller, John R.

1994-05-01

Until recently, the manufacture of toric ophthalmic lenses relied largely upon expensive, manual techniques for generation and polishing. Recent gains in computer numeric control (CNC) technology and tooling enable lens designers to employ single- point diamond, fly-cutting methods in the production of torics. Fly-cutting methods continue to improve, significantly expanding lens design possibilities while lowering production costs. Advantages of CNC fly cutting include precise control of surface geometry, rapid production with high throughput, and high-quality lens surface finishes requiring minimal polishing. As accessibility and affordability increase within the ophthalmic market, torics promise to dramatically expand lens design choices available to consumers.

The significance of ultra-refracted surface gravity waves on sheltered coasts, with application to San Francisco Bay

USGS Publications Warehouse

Hanes, D.M.; Erikson, L.H.

2013-01-01

Ocean surface gravity waves propagating over shallow bathymetry undergo spatial modification of propagation direction and energy density, commonly due to refraction and shoaling. If the bathymetric variations are significant the waves can undergo changes in their direction of propagation (relative to deepwater) greater than 90° over relatively short spatial scales. We refer to this phenomenon as ultra-refraction. Ultra-refracted swell waves can have a powerful influence on coastal areas that otherwise appear to be sheltered from ocean waves. Through a numerical modeling investigation it is shown that San Francisco Bay, one of the earth's largest and most protected natural harbors, is vulnerable to ultra-refracted ocean waves, particularly southwest incident swell. The flux of wave energy into San Francisco Bay results from wave transformation due to the bathymetry and orientation of the large ebb tidal delta, and deep, narrow channel through the Golden Gate. For example, ultra-refracted swell waves play a critical role in the intermittent closure of the entrance to Crissy Field Marsh, a small restored tidal wetland located on the sheltered north-facing coast approximately 1.5 km east of the Golden Gate Bridge.

Sex difference in Double Iron ultra-triathlon performance

PubMed Central

2013-01-01

Background The present study examined the sex difference in swimming (7.8 km), cycling (360 km), running (84 km), and overall race times for Double Iron ultra-triathletes. Methods Sex differences in split times and overall race times of 1,591 men and 155 women finishing a Double Iron ultra-triathlon between 1985 and 2012 were analyzed. Results The annual number of finishes increased linearly for women and exponentially for men. Men achieved race times of 1,716 ± 243 min compared to 1,834 ± 261 min for women and were 118 ± 18 min (6.9%) faster (p < 0.01). Men finished swimming within 156 ± 63 min compared to women with 163 ± 31 min and were 8 ± 32 min (5.1 ± 5.0%) faster (p < 0.01). For cycling, men (852 ± 196 min) were 71 ± 70 min (8.3 ± 3.5%) faster than women (923 ± 126 min) (p < 0.01). Men completed the run split within 710 ± 145 min compared to 739 ± 150 min for women and were 30 ± 5 min (4.2 ± 3.4%) faster (p = 0.03). The annual three fastest men improved race time from 1,650 ± 114 min in 1985 to 1,339 ± 33 min in 2012 (p < 0.01). Overall race time for women remained unchanged at 1,593 ± 173 min with an unchanged sex difference of 27.1 ± 8.6%. In swimming, the split times for the annual three fastest women (148 ± 14 min) and men (127 ± 20 min) remained unchanged with an unchanged sex difference of 26.8 ± 13.5%. In cycling, the annual three fastest men improved the split time from 826 ± 60 min to 666 ± 18 min (p = 0.02). For women, the split time in cycling remained unchanged at 844 ± 54 min with an unchanged sex difference of 25.2 ± 7.3%. In running, the annual fastest three men improved split times from 649 ± 77 min to 532 ± 16 min (p < 0.01). For women, however, the split times remained unchanged at 657 ± 70 min with a stable sex difference of 32.4 ± 12.5%. Conclusions To summarize, the present findings showed that men were faster than women in Double Iron ultra-triathlon, men improved overall race times, cycling and running

High precision detector robot arm system

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

Shu, Deming; Chu, Yong

A method and high precision robot arm system are provided, for example, for X-ray nanodiffraction with an X-ray nanoprobe. The robot arm system includes duo-vertical-stages and a kinematic linkage system. A two-dimensional (2D) vertical plane ultra-precision robot arm supporting an X-ray detector provides positioning and manipulating of the X-ray detector. A vertical support for the 2D vertical plane robot arm includes spaced apart rails respectively engaging a first bearing structure and a second bearing structure carried by the 2D vertical plane robot arm.

Long range surface plasmon resonance with ultra-high penetration depth for self-referenced sensing and ultra-low detection limit using diverging beam approach

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

Isaacs, Sivan, E-mail: sivan.isaacs@gmail.com; Abdulhalim, Ibrahim; NEW CREATE Programme, School of Materials Science and Engineering, 1 CREATE Way, Research Wing, #02-06/08, Singapore 138602

2015-05-11

Using an insulator-metal-insulator structure with dielectric having refractive index (RI) larger than the analyte, long range surface plasmon (SP) resonance exhibiting ultra-high penetration depth is demonstrated for sensing applications of large bioentities at wavelengths in the visible range. Based on the diverging beam approach in Kretschmann-Raether configuration, one of the SP resonances is shown to shift in response to changes in the analyte RI while the other is fixed; thus, it can be used as a built in reference. The combination of the high sensitivity, high penetration depth and self-reference using the diverging beam approach in which a dark linemore » is detected of the high sensitivity, high penetration depth, self-reference, and the diverging beam approach in which a dark line is detected using large number of camera pixels with a smart algorithm for sub-pixel resolution, a sensor with ultra-low detection limit is demonstrated suitable for large bioentities.« less

Ontology-based coupled optimisation design method using state-space analysis for the spindle box system of large ultra-precision optical grinding machine

NASA Astrophysics Data System (ADS)

Wang, Qianren; Chen, Xing; Yin, Yuehong; Lu, Jian

2017-08-01

With the increasing complexity of mechatronic products, traditional empirical or step-by-step design methods are facing great challenges with various factors and different stages having become inevitably coupled during the design process. Management of massive information or big data, as well as the efficient operation of information flow, is deeply involved in the process of coupled design. Designers have to address increased sophisticated situations when coupled optimisation is also engaged. Aiming at overcoming these difficulties involved in conducting the design of the spindle box system of ultra-precision optical grinding machine, this paper proposed a coupled optimisation design method based on state-space analysis, with the design knowledge represented by ontologies and their semantic networks. An electromechanical coupled model integrating mechanical structure, control system and driving system of the motor is established, mainly concerning the stiffness matrix of hydrostatic bearings, ball screw nut and rolling guide sliders. The effectiveness and precision of the method are validated by the simulation results of the natural frequency and deformation of the spindle box when applying an impact force to the grinding wheel.

Probabilistic metrology or how some measurement outcomes render ultra-precise estimates

NASA Astrophysics Data System (ADS)

Calsamiglia, J.; Gendra, B.; Muñoz-Tapia, R.; Bagan, E.

2016-10-01

We show on theoretical grounds that, even in the presence of noise, probabilistic measurement strategies (which have a certain probability of failure or abstention) can provide, upon a heralded successful outcome, estimates with a precision that exceeds the deterministic bounds for the average precision. This establishes a new ultimate bound on the phase estimation precision of particular measurement outcomes (or sequence of outcomes). For probe systems subject to local dephasing, we quantify such precision limit as a function of the probability of failure that can be tolerated. Our results show that the possibility of abstaining can set back the detrimental effects of noise.

Influence of Oxidation Treatments and Surface Finishing on the Electrochemical Behavior of Ni-20Cr HVOF Coatings

NASA Astrophysics Data System (ADS)

Ruiz-Luna, H.; Porcayo-Calderon, J.; Alvarado-Orozco, J. M.; Mora-García, A. G.; Martinez-Gomez, L.; Trápaga-Martínez, L. G.; Muñoz-Saldaña, J.

2017-12-01

The low-temperature electrochemical behavior of HVOF Ni-20Cr coatings was assessed. The coatings were evaluated in different conditions including as-sprayed, as-ground, and heat-treated in air and argon atmospheres. A detailed analysis of the coatings was carried out by means of XRD, SEM, and EPMA, prior and after the corrosion test. The corrosion rate was analyzed in a NaCl solution saturated with CO2. Results demonstrate that the use of a low-oxygen partial pressure favors the formation of a Cr2O3 layer on the surface of the coatings. According to the electrochemical results, the lower corrosion rates were obtained for the heat-treated coatings irrespective of the surface finishing, being the ground and argon heat-treated condition that shows the best corrosion performance. This behavior is due to the synergistic effect of the low-pressure heat treatment and the grinding processes. The grinding promotes a more homogeneous reaction area without surface heterogeneities such as voids, and the pre-oxidation treatment decreases the porosity content of the coating and also allows the growing of a Cr-rich oxide scale which acts as a barrier against the ions of the aqueous solution.

Ductile cutting of silicon microstructures with surface inclination measurement and compensation by using a force sensor integrated single point diamond tool

NASA Astrophysics Data System (ADS)

Chen, Yuan-Liu; Cai, Yindi; Shimizu, Yuki; Ito, So; Gao, Wei; Ju, Bing-Feng

2016-02-01

This paper presents a measurement and compensation method of surface inclination for ductile cutting of silicon microstructures by using a diamond tool with a force sensor based on a four-axis ultra-precision lathe. The X- and Y-directional inclinations of a single crystal silicon workpiece with respect to the X- and Y-motion axes of the lathe slides were measured respectively by employing the diamond tool as a touch-trigger probe, in which the tool-workpiece contact is sensitively detected by monitoring the force sensor output. Based on the measurement results, fabrication of silicon microstructures can be thus carried out directly along the tilted silicon workpiece by compensating the cutting motion axis to be parallel to the silicon surface without time-consuming pre-adjustment of the surface inclination or turning of a flat surface. A diamond tool with a negative rake angle was used in the experiment for superior ductile cutting performance. The measurement precision by using the diamond tool as a touch-trigger probe was investigated. Experiments of surface inclination measurement and ultra-precision ductile cutting of a micro-pillar array and a micro-pyramid array with inclination compensation were carried out respectively to demonstrate the feasibility of the proposed method.

FOCUSR: Feature Oriented Correspondence using Spectral Regularization–A Method for Precise Surface Matching

PubMed Central

Lombaert, Herve; Grady, Leo; Polimeni, Jonathan R.; Cheriet, Farida

2013-01-01

Existing methods for surface matching are limited by the trade-off between precision and computational efficiency. Here we present an improved algorithm for dense vertex-to-vertex correspondence that uses direct matching of features defined on a surface and improves it by using spectral correspondence as a regularization. This algorithm has the speed of both feature matching and spectral matching while exhibiting greatly improved precision (distance errors of 1.4%). The method, FOCUSR, incorporates implicitly such additional features to calculate the correspondence and relies on the smoothness of the lowest-frequency harmonics of a graph Laplacian to spatially regularize the features. In its simplest form, FOCUSR is an improved spectral correspondence method that nonrigidly deforms spectral embeddings. We provide here a full realization of spectral correspondence where virtually any feature can be used as additional information using weights on graph edges, but also on graph nodes and as extra embedded coordinates. As an example, the full power of FOCUSR is demonstrated in a real case scenario with the challenging task of brain surface matching across several individuals. Our results show that combining features and regularizing them in a spectral embedding greatly improves the matching precision (to a sub-millimeter level) while performing at much greater speed than existing methods. PMID:23868776

Nanofinishing of freeform/sculptured surfaces: state-of-the-art

NASA Astrophysics Data System (ADS)

Nagdeve, Leeladhar; Jain, V. K.; Ramkumar, J.

2018-06-01

Freeform surfaces are being used in a multiplicity of applications in different kinds of industries related to Bio-medical (Bio-implants), micro channels in micro fluidics, automotives, turbine blades, impellers of artificial heart pumps, automobiles etc. Different parts in these industries need nano-level surface finish as their functional inevitability. It is very difficult and challenging to achieve high level of surface finish, especially on the components having freeform (or sculptured) surfaces, complex shapes, and 3-D features. Surface finish is a significant factor, which affects life and functionality of a product. Many traditional and advanced finishing processes have been developed for finishing of freeform/sculptured surfaces but still it has not been possible to achieve uniform nano level surface finish specially in case of freeform surfaces. To overcome the limitations of the existing nanofinishing processes, researchers are developing new processes for uniform nanofinishing of freeform surfaces. In this article, an attempt has been made to review different nanofinishing processes employed for freeform surfaces useful in different types of applications. In addition, experimental work, theoretical analysis and existing challenges of the finishing processes have been identified to fill the research gap.

Precision Magnetic Bearing Six Degree of Freedom Stage

NASA Technical Reports Server (NTRS)

Williams, M. E.; Trumper, David L.

1996-01-01

Magnetic bearings are capable of applying force and torque to a suspended object without rigidly constraining any degrees of freedom. Additionally, the resolution of magnetic bearings is limited only by sensors and control, and not by the finish of a bearing surface. For these reasons, magnetic bearings appear to be ideal for precision wafer positioning in lithography systems. To demonstrate this capability a linear magnetic bearing has been constructed which uses variable reluctance actuators to control the motion of a 14.5 kg suspended platen in five degrees of freedom. A Lorentz type linear motor of our own design and construction is used to provide motion and position control in the sixth degree of freedom. The stage performance results verify that the positioning requirements of photolithography can be met with a system of this type. This paper describes the design, control, and performance of the linear magnetic bearing.

Precision lens assembly with alignment turning system

NASA Astrophysics Data System (ADS)

Ho, Cheng-Fang; Huang, Chien-Yao; Lin, Yi-Hao; Kuo, Hui-Jean; Kuo, Ching-Hsiang; Hsu, Wei-Yao; Chen, Fong-Zhi

2017-10-01

The poker chip assembly with high precision lens barrels is widely applied to ultra-high performance optical system. ITRC applies the poker chip assembly technology to the high numerical aperture objective lenses and lithography projection lenses because of its high efficiency assembly process. In order to achieve high precision lens cell for poker chip assembly, an alignment turning system (ATS) is developed. The ATS includes measurement, alignment and turning modules. The measurement module is equipped with a non-contact displacement sensor (NCDS) and an autocollimator (ACM). The NCDS and ACM are used to measure centration errors of the top and the bottom surface of a lens respectively; then the amount of adjustment of displacement and tilt with respect to the rotational axis of the turning machine for the alignment module can be determined. After measurement, alignment and turning processes on the ATS, the centration error of a lens cell with 200 mm in diameter can be controlled within 10 arcsec. Furthermore, a poker chip assembly lens cell with three sub-cells is demonstrated, each sub-cells are measured and accomplished with alignment and turning processes. The lens assembly test for five times by each three technicians; the average transmission centration error of assembly lens is 12.45 arcsec. The results show that ATS can achieve high assembly efficiency for precision optical systems.

Magnetorheological finishing (MRF) of potassium dihydrogen phosphate (KDP) crystals: nonaqueous fluids development, optical finish, and laser damage performance at 1064 nm and 532 nm

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

Menapace, J A; Ehrmann, P R; Bickel, R C

2009-11-05

Over the past year we have been working on specialized MR fluids for polishing KDP crystals. KDP is an extremely difficult material to conventionally polish due to its water solubility, low hardness, and temperature sensitivity. Today, KDP crystals are finished using single-point diamond turning (SPDT) tools and nonaqueous lubricants/coolants. KDP optics fabricated using SPDT, however, are limited to surface corrections due to tool/method characteristics with surface quality driven by microroughness from machine pitch, speed, force, and diamond tool character. MRF polishing offers a means to circumvent many of these issues since it is deterministic which makes the technique practical formore » surface and transmitted wavefront correction, is low force, and is temperature independent. What is lacking is a usable nonaqueous MR fluid that is chemically and physically compatible with KDP which can be used for polishing and subsequently cleaned from the optical surface. In this study, we will present the fluid parameters important in the design and development of nonaqueous MR fluid formulations capable of polishing KDP and how these parameters affect MRF polishing. We will also discuss requirements peculiar to successful KDP polishing and how they affect optical figure/finish and laser damage performance at 1064 nm and 532 nm.« less

Magnetorheological finishing (MRF) of potassium dihydrogen phosphate (KDP) crystals: nonaqueous fluids development, optical finish, and laser damage performance at 1064 nm and 532 nm

NASA Astrophysics Data System (ADS)

Menapace, J. A.; Ehrmann, P. R.; Bickel, R. C.

2009-10-01

Over the past year we have been working on specialized MR fluids for polishing KDP crystals. KDP is an extremely difficult material to conventionally polish due to its water solubility, low hardness, and temperature sensitivity. Today, KDP crystals are finished using single-point diamond turning (SPDT) tools and nonaqueous lubricants/coolants. KDP optics fabricated using SPDT, however, are limited to surface corrections due to tool/method characteristics with surface quality driven by microroughness from machine pitch, speed, force, and diamond tool character. MRF polishing offers a means to circumvent many of these issues since it is deterministic which makes the technique practical for surface and transmitted wavefront correction, is low force, and is temperature independent. What is lacking is a usable nonaqueous MR fluid that is chemically and physically compatible with KDP which can be used for polishing and subsequently cleaned from the optical surface. In this study, we will present the fluid parameters important in the design and development of nonaqueous MR fluid formulations capable of polishing KDP and how these parameters affect MRF polishing. We will also discuss requirements peculiar to successful KDP polishing and how they affect optical figure/finish and laser damage performance at 1064 nm and 532 nm.

Percent recoveries of anthropogenic organic compounds with and without the addition of ascorbic acid to preserve finished-water samples containing free chlorine, 2004-10

USGS Publications Warehouse

Valder, Joshua F.; Delzer, Gregory C.; Bender, David A.; Price, Curtis V.

2011-01-01

This report presents finished-water matrix-spike recoveries of 270 anthropogenic organic compounds with and without the addition of ascorbic acid to preserve water samples containing free chlorine. Percent recoveries were calculated using analytical results from a study conducted during 2004-10 for the National Water-Quality Assessment (NAWQA) Program of the U.S. Geological Survey (USGS). The study was intended to characterize the effect of quenching on finished-water matrix-spike recoveries and to better understand the potential oxidation and transformation of 270 anthropogenic organic compounds. The anthropogenic organic compounds studied include those on analytical schedules 1433, 2003, 2033, 2060, 2020, and 4024 of the USGS National Water Quality Laboratory. Three types of samples were collected from 34 NAWQA locations across the Nation: (1) quenched finished-water samples (not spiked), (2) quenched finished-water matrix-spike samples, and (3) nonquenched finished-water matrix-spike samples. Percent recoveries of anthropogenic organic compounds in quenched and nonquenched finished-water matrix-spike samples are presented. Comparisons of percent recoveries between quenched and nonquenched spiked samples can be used to show how quenching affects finished-water samples. A maximum of 18 surface-water and 34 groundwater quenched finished-water matrix-spike samples paired with nonquenched finished-water matrix-spike samples were analyzed. Percent recoveries for the study are presented in two ways: (1) finished-water matrix-spike samples supplied by surface-water or groundwater, and (2) by use (or source) group category for surface-water and groundwater supplies. Graphical representations of percent recoveries for the quenched and nonquenched finished-water matrix-spike samples also are presented.

Effect of temperature and O-ring gland finish on sealing ability of Viton V747-75

NASA Technical Reports Server (NTRS)

Lach, Cynthia L.

1993-01-01

As a part of the redesign project of the Space Shuttle solid rocket motor (SRM) following the Challenger accident, the field joint was redesigned to minimize the relative joint motion caused by internal motor pressurization during ignition. The O-ring seals and glands for the field joint were designed both to accommodate structural deflections and to promote pressure-assisted sealing. Tests were conducted in various face seal fixtures to evaluate the ability of Viton V747-75 O-rings to seal for a range of temperatures and surface finishes of the redesigned O-ring gland. The effect of surface finish on the sealing performance and wear characteristics of the O-rings was evaluated during simulated launch conditions that included low-frequency vibrations, gap openings, and rapid pressurizations. The effect of contamination on the sealing performance was also investigated. The O-rings sealed throughout the 75 deg F leak check test and for the seal tests from 50 deg F to 120 deg F for the range of surface finishes investigated. Although abrasions were found in the O-rings from pressurization against the rougher finishes, these abrasions were not detrimental to sealing. Below 50 deg F, Viton V747-75 O-rings were insufficiently resilient to track the test gap opening.

A new seamless, smooth, interior, absorptive finishing system

NASA Astrophysics Data System (ADS)

D'Antonio, Peter

2003-04-01

Architects and acousticians have sought a field-applied, absorptive finishing system that resembles a smooth plaster or painted drywall surface, since the dawn of architectural acoustics. Some success has been achieved using sprayed cellulose or cementitious materials, but surface smoothness has been a challenge. A new approach utilizing a thin microporous layer of mineral particles applied over a mineral wool panel will be described. This material can be applied to almost any shape surface, internally pigmented to match almost any color and renovated. It is currently finding application in many architectural applications, including museums. A recent installation in the New Pinakothek Museum in Munich will be illustrated.

Principles of operation, accuracy and precision of an Eye Surface Profiler.

PubMed

Iskander, D Robert; Wachel, Pawel; Simpson, Patrick N D; Consejo, Alejandra; Jesus, Danilo A

2016-05-01

To introduce a newly developed instrument for measuring the topography of the anterior eye, provide principles of its operation and to assess its accuracy and precision. The Eye Surface Profiler is a new technology based on Fourier transform profilometry for measuring the anterior eye surface encompassing the corneo-scleral area. Details of technical principles of operation are provided for the particular case of sequential double fringe projection. Technical limits of accuracy have been assessed for several key parameters such as the carrier frequency, image quantisation level, sensor size, carrier frequency inaccuracy, and level and type of noise. Further, results from both artificial test surfaces as well as real eyes are used to assess precision and accuracy of the device (here benchmarked against one of popular Placido disk videokeratoscopes). Technically, the Eye Surface Profiler accuracy can reach levels below 1 μm for a range of considered key parameters. For the unit tested and using calibrated artificial surfaces, the accuracy of measurement (in terms of RMS error) was below 10 μm for a central measurement area of 8 mm diameter and below 40 μm for an extended measurement area of 16 mm. In some cases, the error reached levels of up to 200 μm at the very periphery of the measured surface (up to 20 mm). The SimK estimates of the test surfaces from the Eye Surface Profiler were in close agreement with those from a Placido disk videokeratoscope with differences no greater than ±0.1 D. For real eyes, the benchmarked accuracy was within ±0.5D for both the spherical and cylindrical SimK components. The Eye Surface Profiler can successfully measure the topography of the entire anterior eye including the cornea, limbus and sclera. It has a great potential to become an optometry clinical tool that could substitute the currently used videokeratoscopes and provide a high quality corneo-scleral topography. © 2016 The Authors Ophthalmic & Physiological

Research on the magnetorheological finishing of large aperture off-axis aspheric optical surfaces for zinc sulfide

NASA Astrophysics Data System (ADS)

Zhang, Yunfei; Huang, Wen; Zheng, Yongcheng; Ji, Fang; Xu, Min; Duan, Zhixin; Luo, Qing; Liu, Qian; Xiao, Hong

2016-03-01

Zinc sulfide is a kind of typical infrared optical material, commonly produced using single point diamond turning (SPDT). SPDT can efficiently produce zinc sulfide aspheric surfaces with micro-roughness and acceptable figure error. However the tool marks left by the diamond turning process cause high micro-roughness that degrades the optical performance when used in the visible region of the spectrum. Magnetorheological finishing (MRF) is a deterministic, sub-aperture polishing technology that is very helpful in improving both surface micro-roughness and surface figure.This paper mainly investigates the MRF technology of large aperture off-axis aspheric optical surfaces for zinc sulfide. The topological structure and coordinate transformation of a MRF machine tool PKC1200Q2 are analyzed and its kinematics is calculated, then the post-processing algorithm model of MRF for an optical lens is established. By taking the post-processing of off-axis aspheric surfacefor example, a post-processing algorithm that can be used for a raster tool path is deduced and the errors produced by the approximate treatment are analyzed. A polishing algorithm of trajectory planning and dwell time based on matrix equation and optimization theory is presented in this paper. Adopting this algorithm an experiment is performed to machining a large-aperture off-axis aspheric surface on the MRF machine developed by ourselves. After several times' polishing, the figure accuracy PV is proved from 3.3λ to 2.0λ and RMS from 0.451λ to 0.327λ. This algorithm is used to polish the other shapes including spheres, aspheres and prisms.

27 CFR 25.231 - Finished beer.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2010-04-01 2010-04-01 false Finished beer. 25.231... OF THE TREASURY LIQUORS BEER Beer Purchased From Another Brewer § 25.231 Finished beer. (a) A brewer may obtain beer in barrels and kegs, finished and ready for sale from another brewer. The purchasing...

27 CFR 25.231 - Finished beer.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2014-04-01 2014-04-01 false Finished beer. 25.231... OF THE TREASURY ALCOHOL BEER Beer Purchased From Another Brewer § 25.231 Finished beer. (a) A brewer may obtain beer in barrels and kegs, finished and ready for sale from another brewer. The purchasing...

27 CFR 25.231 - Finished beer.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2012-04-01 2012-04-01 false Finished beer. 25.231... OF THE TREASURY LIQUORS BEER Beer Purchased From Another Brewer § 25.231 Finished beer. (a) A brewer may obtain beer in barrels and kegs, finished and ready for sale from another brewer. The purchasing...

27 CFR 25.231 - Finished beer.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2013-04-01 2013-04-01 false Finished beer. 25.231... OF THE TREASURY ALCOHOL BEER Beer Purchased From Another Brewer § 25.231 Finished beer. (a) A brewer may obtain beer in barrels and kegs, finished and ready for sale from another brewer. The purchasing...

27 CFR 25.231 - Finished beer.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 27 Alcohol, Tobacco Products and Firearms 1 2011-04-01 2011-04-01 false Finished beer. 25.231... OF THE TREASURY LIQUORS BEER Beer Purchased From Another Brewer § 25.231 Finished beer. (a) A brewer may obtain beer in barrels and kegs, finished and ready for sale from another brewer. The purchasing...

Using femtosecond laser to fabricate highly precise interior three-dimensional microstructures in polymeric flow chip.

PubMed

Lee, Chia-Yu; Chang, Ting-Chou; Wang, Shau-Chun; Chien, Chih-Wei; Cheng, Chung-Wei

2010-10-18

This paper reports using femtosecond laser marker to fabricate the three-dimensional interior microstructures in one closed flow channel of plastic substrate. Strip-like slots in the dimensions of 800 μm×400 μm×65 μm were ablated with pulse Ti:sapphire laser at 800 nm (pulse duration of ∼120 fs with 1 kHz repetition rate) on acrylic slide. After ablation, defocused beams were used to finish the surface of microstructures. Having finally polished with sonication, the laser fabricated structures are highly precise with the arithmetic roughness of 1.5 and 4.5 nm. Fabricating such highly precise microstructures cannot be accomplished with nanosecond laser marking or other mechanical drilling methods. In addition, since laser ablation can directly engrave interior microstructures in one closed chip, glue smearing problems to damage molded microstructures possibly to occur during the chip sealing procedures can be avoided too.

JSC Metal Finishing Waste Minimization Methods

NASA Technical Reports Server (NTRS)

Sullivan, Erica

2003-01-01

THe paper discusses the following: Johnson Space Center (JSC) has achieved VPP Star status and is ISO 9001 compliant. The Structural Engineering Division in the Engineering Directorate is responsible for operating the metal finishing facility at JSC. The Engineering Directorate is responsible for $71.4 million of space flight hardware design, fabrication and testing. The JSC Metal Finishing Facility processes flight hardware to support the programs in particular schedule and mission critical flight hardware. The JSC Metal Finishing Facility is operated by Rothe Joint Venture. The Facility provides following processes: anodizing, alodining, passivation, and pickling. JSC Metal Finishing Facility completely rebuilt in 1998. Total cost of $366,000. All new tanks, electrical, plumbing, and ventilation installed. Designed to meet modern safety, environmental, and quality requirements. Designed to minimize contamination and provide the highest quality finishes.

Damage and annealing recovery of boron-implanted ultra-shallow junction: The correlation between beam current and surface configuration

NASA Astrophysics Data System (ADS)

Chang, Feng-Ming; Wu, Zong-Zhe; Lin, Yen-Fu; Kao, Li-Chi; Wu, Cheng-Ta; JangJian, Shiu-Ko; Chen, Yuan-Nian; Lo, Kuang Yao

2018-03-01

The condition of the beam current in the implantation process is a key issue in the damage rate and structural evolution in the sequent annealing process, especially for ultra-shallow layers. In this work, we develop a compensative optical method combined with UV Raman, X-ray photoelectron spectroscopy (XPS), and X-ray absorption near edge spectroscopy (XANES) to inspect the influence of the beam current in the implantation process. The optima condition of the beam current in the implantation process is determined by higher effective Si-B bond portion in UV Raman spectra and less the peak of B-B bond in XPS spectra which is caused by B cluster defects. Results of XANES indicate that the B oxide layer is formed on the surface of the ultra-shallow junction. The defects in the ultra-shallow junction after annealing are analyzed by novel optical analyses, which cannot be inspected by a traditional thermal wave and resistance measurement. This work exhibits the structural variation of the ultra-shallow junction via a variant beam current and provides a valuable metrology in examining the chemical states and the effective activation in the implantation technology.

9 CFR 381.309 - Finished product inspection.

Code of Federal Regulations, 2011 CFR

2011-01-01

... Finished product inspection. (a) Finished product inspections must be handled according to: (1) A HACCP.... (b)-(c) [Reserved] (d) Procedures for finished product inspections where the HACCP plan for thermally...

Finishing Using Next Generation Technologies

ScienceCinema

Van Tonder, Andries

2018-01-16

Andries van Tonder of Wellcome Trust Sanger Institute discusses a pipeline for finishing genomes to the gold standard on June 3, 2010 at the "Sequencing, Finishing, Analysis in the Future" meeting in Santa Fe, NM.

Impact of initial surface parameters on the final quality of laser micro-polished surfaces

NASA Astrophysics Data System (ADS)

Chow, Michael; Bordatchev, Evgueni V.; Knopf, George K.

2012-03-01

Laser micro-polishing (LμP) is a new laser-based microfabrication technology for improving surface quality during a finishing operation and for producing parts and surfaces with near-optical surface quality. The LμP process uses low power laser energy to melt a thin layer of material on the previously machined surface. The polishing effect is achieved as the molten material in the laser-material interaction zone flows from the elevated regions to the local minimum due to surface tension. This flow of molten material then forms a thin ultra-smooth layer on the top surface. The LμP is a complex thermo-dynamic process where the melting, flow and redistribution of molten material is significantly influenced by a variety of process parameters related to the laser, the travel motions and the material. The goal of this study is to analyze the impact of initial surface parameters on the final surface quality. Ball-end micromilling was used for preparing initial surface of samples from H13 tool steel that were polished using a Q-switched Nd:YAG laser. The height and width of micromilled scallops (waviness) were identified as dominant parameter affecting the quality of the LμPed surface. By adjusting process parameters, the Ra value of a surface, having a waviness period of 33 μm and a peak-to-valley value of 5.9 μm, was reduced from 499 nm to 301 nm, improving the final surface quality by 39.7%.

Packaging Reliability Effect of ENIG and ENEPIG Surface Finishes in Board Level Thermal Test under Long-Term Aging and Cycling

PubMed Central

Shen, Chaobo; Hai, Zhou; Zhao, Cong; Zhang, Jiawei; Evans, John L.; Bozack, Michael J.; Suhling, Jeffrey C.

2017-01-01

This study illustrates test results and comparative literature data on the influence of isothermal aging and thermal cycling associated with Sn-1.0Ag-0.5Cu (SAC105) and Sn-3.0Ag-0.5Cu (SAC305) ball grid array (BGA) solder joints finished with ENIG and ENEPIG on the board side and ENIG on the package side compared with ImAg plating on both sides. The resulting degradation data suggests that the main concern for 0.4 mm pitch 10 mm package size BGA is package side surface finish, not board side. That is, ENIG performs better than immersion Ag for applications involving long-term isothermal aging. SAC305, with a higher relative fraction of Ag3Sn IMC within the solder, performs better than SAC105. SEM and polarized light microscope analysis show cracks propagated from the corners to the center or even to solder bulk, which eventually causes fatigue failure. Three factors are discussed: IMC, grain structure, and Ag3Sn particle. The continuous growth of Cu-Sn intermetallic compounds (IMC) and grains increase the risk of failure, while Ag3Sn particles seem helpful in blocking the crack propagation. PMID:28772811

Surface finish quality of the outer AXAF mirror pair based on x ray measurements of the VETA-I

NASA Technical Reports Server (NTRS)

Hughes, John P.; Schwartz, Daniel A.; Szentgyorgyi, Andrew; Vanspeybroeck, Leon; Zhao, Ping

1992-01-01

We employ the X-ray measurements of the VETA-I taken at the X-Ray Calibration Facility (XRCF) of the Marshall Space Flight Center (MSFC) to extract information about the surface finish quality of the outermost pair of AXAF mirrors. The particular measurements we consider are one dimensional scans of the core of the point response function (PRF) (full width half maximum (FWHM) scans), the encircled energy as a function of radius, and one dimensional scans of the wings of the PRF. We discuss briefly our ray trace model which incorporates the numerous effects present in the VETA-I test, such as the finite source distance, the size and shape of the X-ray source, the residual gravitational distortions of the optic, the despace of the VETA-I, and particulate contamination. We show how the data constrain the amplitude of mirror surface deviations for spatial frequencies greater than about 0.1 mm(exp -1). Constraints on the average amplitude of circumferential slope errors are derived as well.

Note: Ultra-low birefringence dodecagonal vacuum glass cell.

PubMed

Brakhane, Stefan; Alt, Wolfgang; Meschede, Dieter; Robens, Carsten; Moon, Geol; Alberti, Andrea

2015-12-01

We report on an ultra-low birefringence dodecagonal glass cell for ultra-high vacuum applications. The epoxy-bonded trapezoidal windows of the cell are made of SF57 glass, which exhibits a very low stress-induced birefringence. We characterize the birefringence Δn of each window with the cell under vacuum conditions, obtaining values around 10(-8). After baking the cell at 150 °C, we reach a pressure below 10(-10) mbar. In addition, each window is antireflection coated on both sides, which is highly desirable for quantum optics experiments and precision measurements.

Synthetic rubber surface as an alternative to concrete to improve welfare and performance of finishing beef cattle reared on fully slatted flooring.

PubMed

Brscic, M; Ricci, R; Prevedello, P; Lonardi, C; De Nardi, R; Contiero, B; Gottardo, F; Cozzi, G

2015-08-01

The aim of this study was to compare a fully slatted concrete floor (concrete slatted (CS)) with the same floor on which synthetic rubber slats were placed on the concrete slats (rubber slatted (RS)) as housing solution for finishing beef cattle. The present study involved five commercial beef cattle farms in which the floor of at least three pens was kept as fully slatted, and in an equal number of pens a rubber cover was placed on the floor, tightly matching the gap profile of the concrete slats to allow the drainage of manure. A total of 326 finishing beef bulls were used (153 on CS and 173 on RS), and regardless of the floor treatment animals were housed in groups of 6 to 12 bulls/pen with a space allowance of 3.1 ± 0.2 m2/bull. Bulls had similar initial live weights (422.3 kg on CS and 425.0 kg on RS), but bulls on RS were heavier at the end of the finishing period with a higher average daily gain than bulls kept on CS (1.53 v. 1.46 kg/day; P<0.05). The proportion of bulls treated for locomotor problems was lower in RS pens compared with CS. Rubber covering prevented the occurrence of bursitis, but it increased the odds for hoof overgrowth at end of the finishing period. Hoof overgrowth detected in vivo in bulls on RS was confirmed at the slaughterhouse by the longer dorsal wall and diagonal lengths of the hoof as well as by a more acute toe angle. Compared with bulls on CS, bulls on RS showed less inactivity and resting time, increased social interactions, decreased abnormal lying down and unsuccessful attempts to lie down, as well as shortened the time for lying down. Bulls in RS pens were dirtier compared with those in CS pens, likely due to the draining gaps being reduced to 11.6 ± 1.2% of the total pen surface compared with the 16.9 ± 1.7% in CS pens. This study gave further evidence about the positive effects of the RS floor on growth performance and welfare of finishing beef cattle, although compromising cleanliness and hoof overgrowth.

Ultra-wide-field imaging in diabetic retinopathy.

PubMed

Ghasemi Falavarjani, Khalil; Tsui, Irena; Sadda, Srinivas R

2017-10-01

Since 1991, 7-field images captured with 30-50 degree cameras in the Early Treatment Diabetic Retinopathy Study were the gold standard for fundus imaging to study diabetic retinopathy. Ultra-wide-field images cover significantly more area (up to 82%) of the fundus and with ocular steering can in many cases image 100% of the fundus ("panretinal"). Recent advances in image analysis of ultra-wide-field imaging allow for precise measurements of the peripheral retinal lesions. There is a growing consensus in the literature that ultra-wide-field imaging improves detection of peripheral lesions in diabetic retinopathy and leads to more accurate classification of the disease. There is discordance among studies, however, on the correlation between peripheral diabetic lesions and diabetic macular edema and optimal management strategies to treat diabetic retinopathy. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ultra-high vacuum surface analysis study of rhodopsin incorporation into supported lipid bilayers.

PubMed

Michel, Roger; Subramaniam, Varuni; McArthur, Sally L; Bondurant, Bruce; D'Ambruoso, Gemma D; Hall, Henry K; Brown, Michael F; Ross, Eric E; Saavedra, S Scott; Castner, David G

2008-05-06

Planar supported lipid bilayers that are stable under ambient atmospheric and ultra-high-vacuum conditions were prepared by cross-linking polymerization of bis-sorbylphosphatidylcholine (bis-SorbPC). X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS) were employed to investigate bilayers that were cross-linked using either redox-initiated radical polymerization or ultraviolet photopolymerization. The redox method yields a more structurally intact bilayer; however, the UV method is more compatible with incorporation of transmembrane proteins. UV polymerization was therefore used to prepare cross-linked bilayers with incorporated bovine rhodopsin, a light-activated, G-protein-coupled receptor (GPCR). A previous study (Subramaniam, V.; Alves, I. D.; Salgado, G. F. J.; Lau, P. W.; Wysocki, R. J.; Salamon, Z.; Tollin, G.; Hruby, V. J.; Brown, M. F.; Saavedra, S. S. J. Am. Chem. Soc. 2005, 127, 5320-5321) showed that rhodopsin retains photoactivity after incorporation into UV-polymerized bis-SorbPC, but did not address how the protein is associated with the bilayer. In this study, we show that rhodopsin is retained in supported bilayers of poly(bis-SorbPC) under ultra-high-vacuum conditions, on the basis of the increase in the XPS nitrogen concentration and the presence of characteristic amino acid peaks in the ToF-SIMS data. Angle-resolved XPS data show that the protein is inserted into the bilayer, rather than adsorbed on the bilayer surface. This is the first study to demonstrate the use of ultra-high-vacuum techniques for structural studies of supported proteolipid bilayers.

Analysis of fluid film lubrication in artificial hip joint replacements with surfaces of high elastic modulus.

PubMed

Jin, Z M; Dowson, D; Fisher, J

1997-01-01

Lubrication mechanisms and contact mechanics have been analysed for total hip joint replacements made from hard bearing surfaces such as metal-on-metal and ceramic-on-ceramic. A similar analysis for ultra-high molecular weight polyethylene (UHMWPE) against a hard bearing surface has also been carried out and used as a reference. The most important factor influencing the predicted lubrication film thickness has been found to be the radial clearance between the ball and the socket. Full fluid film lubrication may be achieved in these hard/hard bearings provided that the surface finish of the bearing surface and the radial clearance are chosen correctly and maintained. Furthermore, there is a close relation between the predicted contact half width and the predicted lubrication film thickness. Therefore, it is important to analyse the contact mechanics in artificial hip joint replacements. Practical considerations of manufacturing these bearing surfaces have also been discussed.

Non-plasmonic nanoantennas for surface enhanced spectroscopies with ultra-low heat conversion.

PubMed

Caldarola, Martín; Albella, Pablo; Cortés, Emiliano; Rahmani, Mohsen; Roschuk, Tyler; Grinblat, Gustavo; Oulton, Rupert F; Bragas, Andrea V; Maier, Stefan A

2015-08-04

Nanoplasmonics has recently revolutionized our ability to control light on the nanoscale. Using metallic nanostructures with tailored shapes, it is possible to efficiently focus light into nanoscale field 'hot spots'. High field enhancement factors have been achieved in such optical nanoantennas, enabling transformative science in the areas of single molecule interactions, highly enhanced nonlinearities and nanoscale waveguiding. Unfortunately, these large enhancements come at the price of high optical losses due to absorption in the metal, severely limiting real-world applications. Via the realization of a novel nanophotonic platform based on dielectric nanostructures to form efficient nanoantennas with ultra-low light-into-heat conversion, here we demonstrate an approach that overcomes these limitations. We show that dimer-like silicon-based single nanoantennas produce both high surface enhanced fluorescence and surface enhanced Raman scattering, while at the same time generating a negligible temperature increase in their hot spots and surrounding environments.

Influence of Finishing and Polishing Techniques and Abrasion on Transmittance and Roughness of Composite Resins.

PubMed

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.

The BetaCage, an ultra-sensitive screener for surface contamination

NASA Astrophysics Data System (ADS)

Bunker, R.; Ahmed, Z.; Bowles, M. A.; Golwala, S. R.; Grant, D. R.; Kos, M.; Nelson, R. H.; Schnee, R. W.; Rider, A.; Wang, B.; Zahn, A.

2013-08-01

Material screening for identifying low-energy electron emitters and alpha-decaying isotopes is now a prerequisite for rare-event searches (e.g., dark-matter direct detection and neutrinoless double-beta decay) for which surface radiocon-tamination has become an increasingly important background. The BetaCage, a gaseous neon time-projection chamber, is a proposed ultra-sensitive (and nondestructive) screener for alpha-and beta-emitting surface contaminants to which existing screening facilities are insufficiently sensitive. Sensitivity goals are 0.1 betas keV-1 m-2 day-1 and 0.1 alphas m-2 day-1, with the former limited by Compton scattering of photons in the screening samples and (thanks to tracking) the latter expected to be signal-limited; radioassays and simulations indicate backgrounds from detector materials and radon daughters should be subdominant. We report on details of the background simulations and detector design that provide the discrimination, shielding, and radiopurity necessary to reach our sensitivity goals for a chamber with a 95 × 95 cm2 sample area positioned below a 40 cm drift region and monitored by crisscrossed anode and cathode planes consisting of 151 wires each.

Performance enhancement in organic photovoltaic solar cells using iridium (Ir) ultra-thin surface modifier (USM)

NASA Astrophysics Data System (ADS)

Pandey, Rina; Lim, Ju Won; Kim, Jung Hyuk; Angadi, Basavaraj; Choi, Ji Won; Choi, Won Kook

2018-06-01

In this study, Iridium (Ir) metallic layer as an ultra-thin surface modifier (USM) was deposited on ITO coated glass substrate using radio frequency magnetron sputtering for improving the photo-conversion efficiency of organic photovoltaic cells. Ultra-thin Ir acts as a surface modifier replacing the conventional hole transport layer (HTL) PEDOT:PSS in organic photovoltaic (OPV) cells with two different active layers P3HT:PC60BM and PTB7:PC70BM. The Ir USM (1.0 nm) coated on ITO glass substrate showed transmittance of 84.1% and work function of >5.0 eV, which is higher than that of ITO (4.5-4.7 eV). The OPV cells with Ir USM (1.0 nm) exhibits increased power conversion efficiency of 3.70% (for P3HT:PC60BM active layer) and 7.28% (for PTB7:PC70BM active layer) under 100 mW/cm2 illumination (AM 1.5G) which are higher than those of 3.26% and 6.95% for the same OPV cells but with PEDOT:PSS as HTL instead of Ir USM. The results reveal that the chemically stable Ir USM layer could be used as an alternative material for PEDOT:PSS in organic photovoltaic cells.

Effect of Various Finishing Procedures on the Reflectivity (Shine) of Tooth Enamel - An In-vitro Study.

PubMed

Patil, Harshal Ashok; Chitko, Shrikant Shrinivas; Kerudi, Veerendra Virupaxappa; Maheshwari, Amit Ratanlal; Patil, Neeraj Suresh; Tekale, Pawankumar Dnyandeo; Gore, Ketan Ashorao; Zope, Amit Ashok

2016-08-01

Reflectivity of an object is a good parameter for surface finish. As the patient evaluates finishing as a function of gloss/reflectivity/shine an attempt is made here to evaluate changes in surface finish with custom made reflectometer. The aim of the present study was to study the effect of various procedures during orthodontic treatment on the shine of enamel, using a custom made reflectometer. Sixty one extracted premolars were collected and each tooth was mounted on acrylic block. Reflectivity of the teeth was measured as compared to standard before any procedure. One tooth was kept as standard throughout the study. Sixty teeth were acid etched. Reflectivity was measured on custom made reflectometer and readings recorded. Same procedure was repeated after debonding. Then 60 samples were divided into three groups: Group 1 - Tungsten Carbide, Group 2 - Astropol, Group 3- Sof-Lex disc depending upon the finishing method after debonding and reflectivity was measured. The mean percentage of reflectivity after acid etching was 31.4%, debonding 45.5%, Tungsten carbide bur finishing (Group 1) was 58.3%, Astropol (Group 2) 72.8%, and Sof-Lex disc (Group 3) 84.4% as that to the standard. There was statistically very highly significant (p<0.001) difference in reflectivity restored by the three finishing materials in the study. Thus, the light reflection was better in Group 3> Group 2> Group 1. The primary goal was to restore the enamel to its original state after orthodontic treatment. The methods tested in this study could not restore the original enamel reflectivity.

Ultra short laser pulse modification of wave guides

NASA Astrophysics Data System (ADS)

Rosenfeld, Arkadi; Ashkenasi, David

2003-11-01

The high peak powers of ultra short (ps and sub-ps) pulsed lasers available at relatively low single pulse energies potentially allow for a precise localization of photon energy, either on the surface or inside (transparent) materials. Three dimensional micro structuring of bulk transparent media without any sign of mechanical cracking has shown the potential of ultra short laser processing. In this study, the micro structuring of bulk transparent media was used to modify fused silica and especially the cladding-core interface in normal fused silica wave guides. The idea behind this technique is to enforce a local mismatch for total reflection at the interface at minimal mechanic stress to overcome the barrier for enhanced optical out-coupling. The laser-induced modifications were studied in dependence of pulse width, focal alignment, single pulse energy and pulse overlap. Micro traces with a thickness between 3 and 8 μm were generated with a spacing of 10 μm in the subsurface region using sub-ps and ps laser pulses at a wavelength of 800 nm. The optical leakage enforced by a micro spiral pattern is significant and can be utilized for medical applications or potentially also for telecommunications and fiber laser technology.

Evaluation of the Effect of Surface Finish on High-Cycle Fatigue for SLM-IN718

NASA Technical Reports Server (NTRS)

Lambert, Dennis M.

2016-01-01

A high-cycle fatigue (HCF) knockdown factor was estimated for Inconel 718, manufactured with the selective laser melt (SLM) process. This factor is the reduction at a common fatigue life from the maximum stress in fatigue for low-stress ground (LSG) specimens to the maximum stress of those left with the original surface condition. Various vendors provided specimens. To reduce the number of degrees-of-freedom, only one heat treat condition was evaluated. Testing temperatures included room temperature, 800F, 1000F, and 1200F. The two surface conditions were compared at constant lives, where data was available. The recommended knockdown factor of the as-built surface condition (average roughness of approximately 245 micro-inches/inch) versus low-stress ground condition (roughness <= 4 micro-inches/inch) is approximately 1/3 or 33%. This is to say that for the as-built surface condition, a maximum stress of 2/3 of the stress for LSG can be expected to produce the same life in the as built surface condition. As an alternative method, the surface finish was incorporated into a new parameter with the maximum stress. The new parameter was formulated to be similar to the fracture mechanics stress intensity factor, and it was named the pseudo stress intensity factor, Kp. Using Kp, the variance seemed acceptable across all sources, and the knockdown factor was estimated over the range of data identified by Kp where data occurred. A plot of the results suggests that the knockdown factor is a function of temperature, and that for low lives the knockdown is greater than the knockdown observed above about one million cycles, where it stabilizes. One data point at room temperature was clearly different, and the sparsity of data in the higher life region reduces the value of these results. The method does appear to provide useful results, and further characterization of the method is suggested.

Sleep Management Strategy and Performance in an Extreme Mountain Ultra-marathon.

PubMed

Poussel, Mathias; Laroppe, Julien; Hurdiel, Rémy; Girard, Julien; Poletti, Laurence; Thil, Catherine; Didelot, Antoine; Chenuel, Bruno

2015-01-01

We intended to assess the relationship between sleep strategies and performance during the North-Face Ultra-Trail du Mont-Blanc 2013, to test the hypothesis that sleep management can influence athletic performance. Almost all runners specifically adopted sleep management strategies before the race. Among the finishers 72% didn't sleep at all during the race and 28% took a least one break for sleep. Non-sleepers completed the race faster than the sleepers (P = 0.0008). Race time was positively correlated with drowsiness (P < 0.0001) and negatively correlated with the number participations in this race (P = 0.0039). Runners who adopted a sleep management strategy based on increased sleep time before the race completed the race faster (P = 0.0258). Most finishers seemed to be aware of the importance of developing sleep management strategies and increasing sleep time some nights before the race appeared to be the most relevant strategy to improve performance.

Characterization of surface tilt of foundations for high-precision radio-astronomic antennas

NASA Astrophysics Data System (ADS)

Hoff, Brian D.; Puga, Jose P.

2010-07-01

The Atacama Large Millimeter/Submillimeter Array (ALMA) is a joint project between astronomical organizations in Europe, North America, and East Asia, in collaboration with the Republic of Chile. ALMA will consist of at least 54 twelve-meter antennas operating in the millimeter and sub-millimeter wavelength range. It will be located at an altitude above 5000m in the Chajnantor Plateau in northern Chile. There are 192 antenna foundations under construction at ALMA's Array Operations Site (AOS). Interchangeability between foundations will permit a variety of array configurations. Foundations provide the physical interface to the bedrock, as well as to the underground signal and power cable conduits. To achieve ALMA's precision requirements, the antenna pointing angular error budget is strict with anticipated non-repeatable error on the order of a few arc seconds. This level of precision imposes rigorous requirements on antenna foundations. The objective of this study is to demonstrate the methodology of precision tilt measurements combined with finite element simulation predictions to portray the qualitative nature of the antenna foundation surface deformation. Characteristics of foundation surface tilt have been examined in detail. Although the actual foundation has demonstrated much less resistance to tilt than the finite element representation, the simulation has predicted some key characteristics of the tilt pattern. The large deviations from the ideal have incited speculations into the compliance of materials, ambiguities in the construction, thermal effects and several other aspects described herein. This research has served as groundwork to characterize ALMA's foundation surface behavior on a micro-degree level and to identify subsequent studies to pursue. This in turn has contributed to the diagnosis of antenna pointing anomalies.

Using femtosecond laser to fabricate highly precise interior three-dimensional microstructures in polymeric flow chip

PubMed Central

Lee, Chia-Yu; Chang, Ting-Chou; Wang, Shau-Chun; Chien, Chih-Wei; Cheng, Chung-Wei

2010-01-01

This paper reports using femtosecond laser marker to fabricate the three-dimensional interior microstructures in one closed flow channel of plastic substrate. Strip-like slots in the dimensions of 800 μm×400 μm×65 μm were ablated with pulse Ti:sapphire laser at 800 nm (pulse duration of ∼120 fs with 1 kHz repetition rate) on acrylic slide. After ablation, defocused beams were used to finish the surface of microstructures. Having finally polished with sonication, the laser fabricated structures are highly precise with the arithmetic roughness of 1.5 and 4.5 nm. Fabricating such highly precise microstructures cannot be accomplished with nanosecond laser marking or other mechanical drilling methods. In addition, since laser ablation can directly engrave interior microstructures in one closed chip, glue smearing problems to damage molded microstructures possibly to occur during the chip sealing procedures can be avoided too. PMID:21079695

Ultra-Pure Water and Extremophilic Bacteria interactions with Germanium Surfaces

NASA Astrophysics Data System (ADS)

Sah, Vasu R.

Supported by a consortium of semiconductor industry sponsors, an international "TIE" project among 5 National Science Foundation (NSF) Industry/university Cooperative Research Centers discovered that a particular extremophilic microbe, Pseudomonas syzygii, persists in the UltraPure Water (UPW) supplies of chip fabrication facilities (FABs) and can bio-corrode germanium wafers to produce microbe-encased optically transparent crystals. Considered as potentially functional "biochips", this investigation explored mechanisms for the efficient and deliberate production of such microbe-germania adducts as a step toward later testing of their properties as sensors or switches in bioelectronic or biophotonic circuits. Recirculating UPW (Ultra-Pure Water) and other purified water, laminar-flow loops were developed across 50X20x1mm germanium (Ge) prisms, followed by subsequent examination of the prism surfaces using Multiple Attenuated Internal Reflection InfraRed (MAIR-IR) spectroscopy, Contact Potential measurements, Differential Interference Contrast Light Microscopy (DICLM), Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Analysis (EDS), and Electron Spectroscopy for Chemical Analysis (ESCA; XPS). P. syzygii cultures originally obtained from a working FAB at University of Arizona were successfully grown on R2A minimal nutrient media. They were found to be identical to the microbes in stored UPW from the same facility, such microbes routinely capable of nucleation and entrapment within GeO2 crystals on the Ge flow surfaces. Optimum flow rates and exposure times were 1 ml/minute (3.2 s-1 shear rate) for 4 days at room temperature, producing densest crystal arrays at the prism central zones 2-3 cm from the flow inlets. Other flow rates and exposure times have higher shear rate which induces a different nucleation mechanism and saturation of crystal formation. Nucleation events began with square and circular oxide deposits surrounding active attached bacteria

25 CFR 301.8 - Finish.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 25 Indians 2 2010-04-01 2010-04-01 false Finish. 301.8 Section 301.8 Indians INDIAN ARTS AND CRAFTS BOARD, DEPARTMENT OF THE INTERIOR NAVAJO, PUEBLO, AND HOPI SILVER AND TURQUOISE PRODUCTS; STANDARDS § 301.8 Finish. All silver is to be hand polished. ...

Ultra-wideband filtering of spoof surface plasmon polaritons using deep subwavelength planar structures

PubMed Central

Hu, Ming Zhe; Zhang, Hao Chi; Yin, Jia Yuan; Ding, Zhao; Liu, Jun Feng; Tang, Wen Xuan; Cui, Tie Jun

2016-01-01

Novel ultra-wideband filtering of spoof surface plasmon polaritons (SPPs) is proposed in the microwave frequency using deep subwavelength planar structures printed on thin and flexible dielectric substrate. The proposed planar SPPs waveguide is composed of two mirror-oriented metallic corrugated strips, which are further decorated with parallel-arranged slots in the main corrugated strips. This compound structure provides deep subwavelength field confinement as well as flexible parameters when employed as a plasmonic waveguide, which is potential to construct miniaturization. Using momentum and impedance matching technology, we achieve a smooth conversion between the proposed SPPs waveguide and the conventional transmission line. To verify the validity of the design, we fabricate a spoof SPPs filter, and the measured results illustrate excellent performance, in which the reflection coefficient is less than −10 dB within the −3 dB passband from 1.21 GHz to 7.21 GHz with the smallest insertion loss of 1.23 dB at 2.21 GHz, having very good agreements with numerical simulations. The ultra-wideband filter with low insertion loss and high transmission efficiency possesses great potential in modern communication systems. PMID:27883028

Ultra-wideband filtering of spoof surface plasmon polaritons using deep subwavelength planar structures.

PubMed

Hu, Ming Zhe; Zhang, Hao Chi; Yin, Jia Yuan; Ding, Zhao; Liu, Jun Feng; Tang, Wen Xuan; Cui, Tie Jun

2016-11-24

Novel ultra-wideband filtering of spoof surface plasmon polaritons (SPPs) is proposed in the microwave frequency using deep subwavelength planar structures printed on thin and flexible dielectric substrate. The proposed planar SPPs waveguide is composed of two mirror-oriented metallic corrugated strips, which are further decorated with parallel-arranged slots in the main corrugated strips. This compound structure provides deep subwavelength field confinement as well as flexible parameters when employed as a plasmonic waveguide, which is potential to construct miniaturization. Using momentum and impedance matching technology, we achieve a smooth conversion between the proposed SPPs waveguide and the conventional transmission line. To verify the validity of the design, we fabricate a spoof SPPs filter, and the measured results illustrate excellent performance, in which the reflection coefficient is less than -10 dB within the -3 dB passband from 1.21 GHz to 7.21 GHz with the smallest insertion loss of 1.23 dB at 2.21 GHz, having very good agreements with numerical simulations. The ultra-wideband filter with low insertion loss and high transmission efficiency possesses great potential in modern communication systems.

X-ray diffraction gratings: Precise control of ultra-low blaze angle via anisotropic wet etching

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

Voronov, Dmitriy L.; Naulleau, Patrick; Gullikson, Eric M.

2016-07-25

Diffraction gratings are used from micron to nanometer wavelengths as dispersing elements in optical instruments. At shorter wavelengths, crystals can be used as diffracting elements, but due to the 3D nature of the interaction with light are wavelength selective rather than wavelength dispersing. There is an urgent need to extend grating technology into the x-ray domain of wavelengths from 1 to 0.1 nm, but this requires the use of gratings that have a faceted surface in which the facet angles are very small, typically less than 1°. Small facet angles are also required in the extreme ultra-violet and soft x-ray energymore » ranges in free electron laser applications, in order to reduce power density below a critical damage threshold. In this work, we demonstrate a technique based on anisotropic etching of silicon designed to produce very small angle facets with a high degree of perfection.« less

27 CFR 19.601 - Finished products records.

Code of Federal Regulations, 2011 CFR

2011-04-01

... Finished products records. (a) Bottling and packaging. A proprietor must maintain daily transaction records and a daily summary record of the kind and quantity of finished products bottled or packaged within... daily records of the disposition of finished products from the processing account at the distilled...

Impact of Isothermal Aging on Long-Term Reliability of Fine-Pitch Ball Grid Array Packages with Sn-Ag-Cu Solder Interconnects: Surface Finish Effects

NASA Astrophysics Data System (ADS)

Lee, Tae-Kyu; Ma, Hongtao; Liu, Kuo-Chuan; Xue, Jie

2010-12-01

The interaction between isothermal aging and the long-term reliability of fine-pitch ball grid array (BGA) packages with Sn-3.0Ag-0.5Cu (wt.%) solder ball interconnects was investigated. In this study, 0.4-mm fine-pitch packages with 300- μm-diameter Sn-Ag-Cu solder balls were used. Two different package substrate surface finishes were selected to compare their effects on the final solder composition, especially the effect of Ni, during thermal cycling. To study the impact on thermal performance and long-term reliability, samples were isothermally aged and thermally cycled from 0°C to 100°C with 10 min dwell time. Based on Weibull plots for each aging condition, package lifetime was reduced by approximately 44% by aging at 150°C. Aging at 100°C showed a smaller impact but similar trend. The microstructure evolution was observed during thermal aging and thermal cycling with different phase microstructure transformations between electrolytic Ni/Au and organic solderability preservative (OSP) surface finishes, focusing on the microstructure evolution near the package-side interface. Different mechanisms after aging at various conditions were observed, and their impacts on the fatigue lifetime of solder joints are discussed.

Self-cleaning effect in high quality percussion ablating of cooling hole by picosecond ultra-short pulse laser

NASA Astrophysics Data System (ADS)

Zhao, Wanqin; Yu, Zhishui

2018-06-01

Comparing with the trepanning technology, cooling hole could be processed based on the percussion drilling with higher processing efficiency. However, it is widely believed that the ablating precision of hole is lower for percussion drilling than for trepanning, wherein, the melting spatter materials around the hole surface and the recast layer inside the hole are the two main issues for reducing the ablating precision of hole, especially for the recast layer, it can't be eliminated completely even through the trepanning technology. In this paper, the self-cleaning effect which is a particular property just for percussion ablating of holes has been presented in detail. In addition, the reasons inducing the self-cleaning effect have been discussed. At last, based on the self-cleaning effect of percussion drilling, high quality cooling hole without the melting spatter materials around the hole surface and recast layer inside the hole could be ablated in nickel-based superalloy by picosecond ultra-short pulse laser.

Non-plasmonic nanoantennas for surface enhanced spectroscopies with ultra-low heat conversion

PubMed Central

Caldarola, Martín; Albella, Pablo; Cortés, Emiliano; Rahmani, Mohsen; Roschuk, Tyler; Grinblat, Gustavo; Oulton, Rupert F.; Bragas, Andrea V.; Maier, Stefan A.

2015-01-01

Nanoplasmonics has recently revolutionized our ability to control light on the nanoscale. Using metallic nanostructures with tailored shapes, it is possible to efficiently focus light into nanoscale field ‘hot spots'. High field enhancement factors have been achieved in such optical nanoantennas, enabling transformative science in the areas of single molecule interactions, highly enhanced nonlinearities and nanoscale waveguiding. Unfortunately, these large enhancements come at the price of high optical losses due to absorption in the metal, severely limiting real-world applications. Via the realization of a novel nanophotonic platform based on dielectric nanostructures to form efficient nanoantennas with ultra-low light-into-heat conversion, here we demonstrate an approach that overcomes these limitations. We show that dimer-like silicon-based single nanoantennas produce both high surface enhanced fluorescence and surface enhanced Raman scattering, while at the same time generating a negligible temperature increase in their hot spots and surrounding environments. PMID:26238815

Design and performance of an ultra-wideband stepped-frequency radar with precise frequency control for landmine and IED detection

NASA Astrophysics Data System (ADS)

Phelan, Brian R.; Sherbondy, Kelly D.; Ranney, Kenneth I.; Narayanan, Ram M.

2014-05-01

The Army Research Laboratory (ARL) has developed an impulse-based vehicle-mounted forward-looking ultra- wideband (UWB) radar for imaging buried landmines and improvised explosive devices (IEDs). However, there is no control of the radiated spectrum in this system. As part of ARL's Partnerships in Research Transition (PIRT) program, the above deficiency is addressed by the design of a Stepped-Frequency Radar (SFR) which allows for precise control over the radiated spectrum, while still maintaining an effective ultra-wide bandwidth. The SFR utilizes a frequency synthesizer which can be configured to excise prohibited and interfering frequency bands and also implement frequency-hopping capabilities. The SFR is designed to be a forward-looking ground- penetrating (FLGPR) Radar utilizing a uniform linear array of sixteen (16) Vivaldi notch receive antennas and two (2) Quad-ridge horn transmit antennas. While a preliminary SFR consisting of four (4) receive channels has been designed, this paper describes major improvements to the system, and an analysis of expected system performance. The 4-channel system will be used to validate the SFR design which will eventually be augmented in to the full 16-channel system. The SFR has an operating frequency band which ranges from 300 - 2000 MHz, and a minimum frequency step-size of 1 MHz. The radar system is capable of illuminating range swaths that have maximum extents of 30 to 150 meters (programmable). The transmitter has the ability to produce approximately -2 dBm/MHz average power over the entire operating frequency range. The SFR will be used to determine the practicality of detecting and classifying buried and concealed landmines and IEDs from safe stand-off distances.

Note: Ultra-low birefringence dodecagonal vacuum glass cell

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

Brakhane, Stefan, E-mail: brakhane@iap.uni-bonn.de; Alt, Wolfgang; Meschede, Dieter

We report on an ultra-low birefringence dodecagonal glass cell for ultra-high vacuum applications. The epoxy-bonded trapezoidal windows of the cell are made of SF57 glass, which exhibits a very low stress-induced birefringence. We characterize the birefringence Δn of each window with the cell under vacuum conditions, obtaining values around 10{sup −8}. After baking the cell at 150 °C, we reach a pressure below 10{sup −10} mbar. In addition, each window is antireflection coated on both sides, which is highly desirable for quantum optics experiments and precision measurements.

Precision Cleaning and Protection of Coated Optical Components for NIF Small Optics

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

Phelps, Jim

The purpose of this procedure shall be to define the precision cleaning of finished, coated, small optical components for NIF at Lawrence Livermore National Laboratories. The term “small optical components” includes coated optics that are set into simple mounts, as well as coated, un-mounted optics.

Surface passivation investigation on ultra-thin atomic layer deposited aluminum oxide layers for their potential application to form tunnel layer passivated contacts

NASA Astrophysics Data System (ADS)

Xin, Zheng; Ling, Zhi Peng; Nandakumar, Naomi; Kaur, Gurleen; Ke, Cangming; Liao, Baochen; Aberle, Armin G.; Stangl, Rolf

2017-08-01

The surface passivation performance of atomic layer deposited ultra-thin aluminium oxide layers with different thickness in the tunnel layer regime, i.e., ranging from one atomic cycle (∼0.13 nm) to 11 atomic cycles (∼1.5 nm) on n-type silicon wafers is studied. The effect of thickness and thermal activation on passivation performance is investigated with corona-voltage metrology to measure the interface defect density D it(E) and the total interface charge Q tot. Furthermore, the bonding configuration variation of the AlO x films under various post-deposition thermal activation conditions is analyzed by Fourier transform infrared spectroscopy. Additionally, poly(3,4-ethylenedioxythiophene) poly(styrene sulfonate) is used as capping layer on ultra-thin AlO x tunneling layers to further reduce the surface recombination current density to values as low as 42 fA/cm2. This work is a useful reference for using ultra-thin ALD AlO x layers as tunnel layers in order to form hole selective passivated contacts for silicon solar cells.

Effect of Binder and Mold parameters on Collapsibility and Surface Finish of Gray Cast Iron No-bake Sand Molds

NASA Astrophysics Data System (ADS)

Srinivasulu Reddy, K.; Venkata Reddy, Vajrala; Mandava, Ravi Kumar

2017-08-01

Chemically bonded no-bake molds and cores have good mechanical properties and produce dimensionally accurate castings compared to green sand molds. Poor collapsibility property of CO2 hardened sodium silicate bonded sand mold and phenolic urethane no-bake (PUN) binder system, made the reclamation of the sands more important. In the present work fine silica sand is mixed with phenolic urethane no-bake binder and the sand sets in a very short time within few minutes. In this paper it is focused on optimizing the process parameters of PUN binder based sand castings for better collapsibility and surface finish of gray cast iron using Taguchi design. The findings were successfully verified through experiments.

Cu(In,Ga)Se2 surface treatment with Na and NaF: A combined photoelectron spectroscopy and surface photovoltage study in ultra-high vacuum

NASA Astrophysics Data System (ADS)

Parvan, V.; Mizrak, A.; Majumdar, I.; Ümsür, B.; Calvet, W.; Greiner, D.; Kaufmann, C. A.; Dittrich, T.; Avancini, E.; Lauermann, I.

2018-06-01

Either metallic Na or NaF were deposited onto Cu(In,Ga)Se2 surfaces and studied by photoelectron spectroscopy and surface photovoltage spectroscopy without breaking the ultra-high vacuum. The deposition of elemental Na at room temperature led to the formation of an intermediate Cu and Ga rich layer at the CIGSe surface, whereas for NaF the composition of the CIGSe surface remained unchanged. A metal like surface induced by an inverted near surface region with a reduced number of defect states was formed after the deposition of Na. Under the chosen experimental conditions, the near surface layer was independent on the amount of Na and stable in time. In contrast, the usage of NaF weakened the inversion and led to an increased band bending compared to the untreated CIGSe sample. The SPV signals decreased with proceeding time after the deposition of NaF.

Finishes checklist : a guide to achieving optimum coating performance on exterior wood surfaces

Treesearch

Tony Bonura; Steve Bussjeager; Lynne Christensen; George Daisey; Tom Daniels; Mark Hirsch; Charles J. Jourdain; D. Douglas Mall; Bob Springate; Louis E. Wagner; Warren Harry; R. Sam Williams

2004-01-01

When the time comes for a consumer to select the wood and finish types for a given outdoor project, there is a wide variety of sources of information, articles, and opinions available. Occasionally, these sources will conflict, mostly due to the data available at the time of publication, or practical experience based on a snapshot of conditions at a given time period....

Spot breeding method to evaluate the determinism of magnetorheological finishing

NASA Astrophysics Data System (ADS)

Yang, Hang; He, Jianguo; Huang, Wen; Zhang, Yunfei

2017-03-01

The influences of immersion depth of magnetorheological finishing (MRF) on the shape and material removal rate (MRR) of removal function are theoretically investigated to establish the spot transition mechanism. Based on this mechanism, for the first time, the spot breeding method to predict the shape and removal rate of MRF spot is proposed. The UBK7 optical parts are polished to verify the proposed method on experimental installation PKC-1000Q2 developed by ourselves. The experimental results reveal that the predictions of shape and MRR with this method are precise. The proposed method provides a basis for analyzing the determinism of MRF due to geometry of the process.

The BetaCage, an ultra-sensitive screener for surface contamination

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

Bunker, R.; Bowles, M. A.; Schnee, R. W.

Material screening for identifying low-energy electron emitters and alpha-decaying isotopes is now a prerequisite for rare-event searches (e.g., dark-matter direct detection and neutrinoless double-beta decay) for which surface radiocon-tamination has become an increasingly important background. The BetaCage, a gaseous neon time-projection chamber, is a proposed ultra-sensitive (and nondestructive) screener for alpha-and beta-emitting surface contaminants to which existing screening facilities are insufficiently sensitive. Sensitivity goals are 0.1 betas keV{sup −1} m{sup −2} day{sup −1} and 0.1 alphas m{sup −2} day{sup −1}, with the former limited by Compton scattering of photons in the screening samples and (thanks to tracking) the latter expectedmore » to be signal-limited; radioassays and simulations indicate backgrounds from detector materials and radon daughters should be subdominant. We report on details of the background simulations and detector design that provide the discrimination, shielding, and radiopurity necessary to reach our sensitivity goals for a chamber with a 95 × 95 cm{sup 2} sample area positioned below a 40 cm drift region and monitored by crisscrossed anode and cathode planes consisting of 151 wires each.« less

High precision triangular waveform generator

DOEpatents

Mueller, Theodore R.

1983-01-01

An ultra-linear ramp generator having separately programmable ascending and descending ramp rates and voltages is provided. Two constant current sources provide the ramp through an integrator. Switching of the current at current source inputs rather than at the integrator input eliminates switching transients and contributes to the waveform precision. The triangular waveforms produced by the waveform generator are characterized by accurate reproduction and low drift over periods of several hours. The ascending and descending slopes are independently selectable.

High-precision triangular-waveform generator

DOEpatents

Mueller, T.R.

1981-11-14

An ultra-linear ramp generator having separately programmable ascending and decending ramp rates and voltages is provided. Two constant current sources provide the ramp through an integrator. Switching of the current at current source inputs rather than at the integrator input eliminates switching transients and contributes to the waveform precision. The triangular waveforms produced by the waveform generator are characterized by accurate reproduction and low drift over periods of several hours. The ascending and descending slopes are independently selectable.

Application of precise altimetry to the study of precise leveling of the sea surface, the Earth's gravity field, and the rotation of the Earth

NASA Technical Reports Server (NTRS)

Segawa, J.; Ganeko, Y.; Sasaki, M.; Mori, T.; Ooe, M.; Nakagawa, I.; Ishii, H.; Hagiwara, Y.

1991-01-01

Our program includes five research items: (1) determination of a precision geoid and gravity anomaly field; (2) precise leveling and detection of tidal changes of the sea surface and study of the role of the tide in the global energy exchange; (3) oceanic effect on the Earth's rotation and polar motion; (4) geological and geophysical interpretation of the altimetry gravity field; and (5) evaluation of the effectiveness of local tracking of TOPEX/POSEIDON by use of a laser tracker.

Computer Generated Diffraction Patterns Of Rough Surfaces

NASA Astrophysics Data System (ADS)

Rakels, Jan H.

1989-03-01

It is generally accepted, that optical methods are the most promising for the in-process measurement of surface finish. These methods have the advantages of being non-contacting and fast data acquisition. In the Micro-Engineering Centre at the University of Warwick, an optical sensor has been devised which can measure the rms roughness, slope and wavelength of turned and precision ground surfaces. The operation of this device is based upon the Kirchhoff-Fresnel diffraction integral. Application of this theory to ideal turned surfaces is straightforward, and indeed the theoretically calculated diffraction patterns are in close agreement with patterns produced by an actual optical instrument. Since it is mathematically difficult to introduce real surface profiles into the diffraction integral, a computer program has been devised, which simulates the operation of the optical sensor. The program produces a diffraction pattern as a graphical output. Comparison between computer generated and actual diffraction patterns of the same surfaces show a high correlation.

Forest Products Laboratory natural finish

Treesearch

J. M. Black; D. F. Laughnan; E. A. Mraz

1979-01-01

A simple and durable exterior natural finish developed at the Forest Products Laboratory is described. The finish is classified as a semi-transparent oil-base penetrating stain that effectively retains much of the natural grain and texture of wood when exposed to the weather. The directions for preparation are included as are the recommendations for application to both...

Abrasive rolling effects on material removal and surface finish in chemical mechanical polishing analyzed by molecular dynamics simulation

NASA Astrophysics Data System (ADS)

Si, Lina; Guo, Dan; Luo, Jianbin; Lu, Xinchun; Xie, Guoxin

2011-04-01

In an abrasive chemical mechanical polishing (CMP) process, materials were considered to be removed by abrasive sliding and rolling. Abrasive sliding has been investigated by many molecular dynamics (MD) studies; while abrasive rolling was usually considered to be negligible and therefore was rarely investigated. In this paper, an MD simulation was used to study the effects of abrasive rolling on material removal and surface finish in the CMP process. As the silica particle rolled across the silicon substrate, some atoms of the substrate were dragged out from their original positions and adhered to the silica particle, leaving some atomic vacancies on the substrate surface. Meanwhile, a high quality surface could be obtained. During the abrasive rolling process, the influencing factors of material removal, e.g., external down force and driving force, were also discussed. Finally, MD simulations were carried out to examine the effects of abrasive sliding on material removal under the same external down force as abrasive rolling. The results showed that the ability of abrasive rolling to remove material on the atomic scale was not notably inferior to that of abrasive sliding. Therefore, it can be proposed that both abrasive sliding and rolling play important roles in material removal in the abrasive CMP of the silicon substrate.

History of magnetorheological finishing

NASA Astrophysics Data System (ADS)

Harris, Daniel C.

2011-06-01

Magnetorheological finishing (MRF) is a deterministic method for producing complex optics with figure accuracy <50 nm and surface roughness <1 nm. MRF was invented at the Luikov Institute of Heat and Mass Transfer in Minsk, Belarus in the late 1980s by a team led by William Kordonski. When the Soviet Union opened up, New York businessman Lowell Mintz was invited to Minsk in 1990 to explore possibilities for technology transfer. Mintz was told of the potential for MRF, but did not understand whether it had value. Mintz was referred to Harvey Pollicove at the Center for Optics Manufacturing of the University of Rochester. As a result of their conversation, they sent Prof. Steve Jacobs to visit Minsk and evaluate MRF. From Jacobs' positive findings, and with support from Lowell Mintz, Kordonski and his colleagues were invited in 1993 to work at the Center for Optics Manufacturing with Jacobs and Don Golini to refine MRF technology. A "preprototype" finishing machine was operating by 1994. Prof. Greg Forbes and doctoral student Paul Dumas developed algorithms for deterministic control of MRF. In 1996, Golini recognized the commercial potential of MRF, secured investment capital from Lowell Mintz, and founded QED Technologies. The first commercial MRF machine was unveiled in 1998. It was followed by more advanced models and by groundbreaking subaperture stitching interferometers for metrology. In 2006, QED was acquired by and became a division of Cabot Microelectronics. This paper recounts the history of the development of MRF and the founding of QED Technologies.

Surface Studies of Ultra Strength Drilling Steel after Corrosion Fatigue in Simulated Sour Environment

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

M. Ziomek-Moroz; J.A. Hawk; R. Thodla

2012-05-06

The Unites States predicted 60% growth in energy demand by 2030 makes oil and natural gas primary target fuels for energy generation. The fact that the peak of oil production from shallow wells (< 5000 m) is about to be reached, thereby pushing the oil and natural gas industry into deeper wells. However, drilling to depths greater than 5000 m requires increasing the strength-to weight ratio of the drill pipe materials. Grade UD-165 is one of the ultra- high yield strength carbon steels developed for ultra deep drilling (UDD) activities. Drilling UDD wells exposes the drill pipes to Cl{sup -},more » HCO{sub 3}{sup -}/CO{sub 3}{sup 2-}, and H{sub 2}S-containig corrosive environments (i.e., sour environments) at higher pressures and temperatures compared to those found in conventional wells. Because of the lack of synergism within the service environment, operational stresses can result in catastrophic brittle failures characteristic for environmentally assisted cracking (EAC). Approximately 75% of all drill string failures are caused by fatigue or corrosion fatigue. Since there is no literature data on the corrosion fatigue performance of UD-165 in sour environments, research was initiated to better clarify the fatigue crack growth (FCGR) behavior of this alloy in UDD environments. The FCGR behavior of ultra-strength carbon steel, grade UD-165, was investigated by monitoring crack growth rate in deaerated 5%NaCl solution buffered with NaHCO{sub 3}/Na{sub 2}CO{sub 3} and in contact with H{sub 2}S. The partial pressure of H{sub 2}S (p{sub H2S}) was 0.83 kPa and pH of the solution was adjusted by NaOH to 12. The fatigue experiments were performed at 20 and 85 C in an autoclave with surface investigations augmented by scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) spectroscopy. In this study, research focused on surface analyses supported by the fatigue crack growth rate measurements. Fig. 1 shows an SEM micrograph of the crack that propagated

Dwell time algorithm based on the optimization theory for magnetorheological finishing

NASA Astrophysics Data System (ADS)

Zhang, Yunfei; Wang, Yang; Wang, Yajun; He, Jianguo; Ji, Fang; Huang, Wen

2010-10-01

Magnetorheological finishing (MRF) is an advanced polishing technique capable of rapidly converging to the required surface figure. This process can deterministically control the amount of the material removed by varying a time to dwell at each particular position on the workpiece surface. The dwell time algorithm is one of the most important key techniques of the MRF. A dwell time algorithm based on the1 matrix equation and optimization theory was presented in this paper. The conventional mathematical model of the dwell time was transferred to a matrix equation containing initial surface error, removal function and dwell time function. The dwell time to be calculated was just the solution to the large, sparse matrix equation. A new mathematical model of the dwell time based on the optimization theory was established, which aims to minimize the 2-norm or ∞-norm of the residual surface error. The solution meets almost all the requirements of precise computer numerical control (CNC) without any need for extra data processing, because this optimization model has taken some polishing condition as the constraints. Practical approaches to finding a minimal least-squares solution and a minimal maximum solution are also discussed in this paper. Simulations have shown that the proposed algorithm is numerically robust and reliable. With this algorithm an experiment has been performed on the MRF machine developed by ourselves. After 4.7 minutes' polishing, the figure error of a flat workpiece with a 50 mm diameter is improved by PV from 0.191λ(λ = 632.8 nm) to 0.087λ and RMS 0.041λ to 0.010λ. This algorithm can be constructed to polish workpieces of all shapes including flats, spheres, aspheres, and prisms, and it is capable of improving the polishing figures dramatically.

Effects of finishing/polishing techniques on microleakage of resin-modified glass ilonomer cement restorations.

PubMed

Yap, Adrian U J; Yap, W Y; Yeo, Egwin J C; Tan, Jane W S; Ong, Debbie S B

2003-01-01

This study investigated the effect of finishing/polishing techniques on the microleakage of resin-modified glass ionomer restorations. Class V preparations were made on the buccal and lingual/palatal surfaces of freshly extracted teeth. The cavities on each tooth were restored with Fuji II LC (FT [GC]) and Photac-Fil Quick (PF [3M-ESPE]) according to manufacturers' instructions. Immediately after light-polymerization, gross finishing was done with eight-fluted tungsten carbide burs. The teeth were then randomly divided into four groups and finishing/polishing was done with one of the following systems: (a) Robot Carbides (RC); (b) Super-Snap system (SS); (c) OneGloss (OG) and (d) CompoSite Polishers (CS). The sample size for each material-finishing/polishing system combination was eight. After finishing/polishing, the teeth were stored in distilled water at 37 degrees C for one week. The root apices were then sealed with acrylic and two coats of varnish was applied 1 mm beyond the restoration margins. The teeth were subsequently subjected to dye penetration testing (0.5% basic fuchsin), sectioned and scored. Data was analyzed using Kruskal-Wallis and Mann-Whitney U tests at a significance level of 0.05. Results of statistical analysis were as follows: Enamel margins: PF-OGfinishing/polishing technique, leakage at dentin margins was significantly greater than at enamel margins for FT. For PF, no significant difference in leakage scores was observed between dentin and enamel with the exception of finishing/polishing with OG. FT restorations had significantly less enamel and dentin leakage than PF restorations when treated with OG. The effect of finishing/polishing techniques on microleakage was both tissue and material dependent.

On the characterization of ultra-precise X-ray optical components: advances and challenges in ex situ metrology

PubMed Central

Siewert, F.; Buchheim, J.; Zeschke, T.; Störmer, M.; Falkenberg, G.; Sankari, R.

2014-01-01

To fully exploit the ultimate source properties of the next-generation light sources, such as free-electron lasers (FELs) and diffraction-limited storage rings (DLSRs), the quality requirements for gratings and reflective synchrotron optics, especially mirrors, have significantly increased. These coherence-preserving optical components for high-brightness sources will feature nanoscopic shape accuracies over macroscopic length scales up to 1000 mm. To enable high efficiency in terms of photon flux, such optics will be coated with application-tailored single or multilayer coatings. Advanced thin-film fabrication of today enables the synthesis of layers on the sub-nanometre precision level over a deposition length of up to 1500 mm. Specifically dedicated metrology instrumentation of comparable accuracy has been developed to characterize such optical elements. Second-generation slope-measuring profilers like the nanometre optical component measuring machine (NOM) at the BESSY-II Optics laboratory allow the inspection of up to 1500 mm-long reflective optical components with an accuracy better than 50 nrad r.m.s. Besides measuring the shape on top of the coated mirror, it is of particular interest to characterize the internal material properties of the mirror coating, which is the domain of X-rays. Layer thickness, density and interface roughness of single and multilayer coatings are investigated by means of X-ray reflectometry. In this publication recent achievements in the field of slope measuring metrology are shown and the characterization of different types of mirror coating demonstrated. Furthermore, upcoming challenges to the inspection of ultra-precise optical components designed to be used in future FEL and DLSR beamlines are discussed. PMID:25177985

Ultra-wideband WDM VCSEL arrays by lateral heterogeneous integration

NASA Astrophysics Data System (ADS)

Geske, Jon

Advancements in heterogeneous integration are a driving factor in the development of evermore sophisticated and functional electronic and photonic devices. Such advancements will merge the optical and electronic capabilities of different material systems onto a common integrated device platform. This thesis presents a new lateral heterogeneous integration technology called nonplanar wafer bonding. The technique is capable of integrating multiple dissimilar semiconductor device structures on the surface of a substrate in a single wafer bond step, leaving different integrated device structures adjacent to each other on the wafer surface. Material characterization and numerical simulations confirm that the material quality is not compromised during the process. Nonplanar wafer bonding is used to fabricate ultra-wideband wavelength division multiplexed (WDM) vertical-cavity surface-emitting laser (VCSEL) arrays. The optically-pumped VCSEL arrays span 140 nm from 1470 to 1610 nm, a record wavelength span for devices operating in this wavelength range. The array uses eight wavelength channels to span the 140 nm with all channels separated by precisely 20 nm. All channels in the array operate single mode to at least 65°C with output power uniformity of +/- 1 dB. The ultra-wideband WDM VCSEL arrays are a significant first step toward the development of a single-chip source for optical networks based on coarse WDM (CWDM), a low-cost alternative to traditional dense WDM. The CWDM VCSEL arrays make use of fully-oxidized distributed Bragg reflectors (DBRs) to provide the wideband reflectivity required for optical feedback and lasing across 140 rim. In addition, a novel optically-pumped active region design is presented. It is demonstrated, with an analytical model and experimental results, that the new active-region design significantly improves the carrier uniformity in the quantum wells and results in a 50% lasing threshold reduction and a 20°C improvement in the peak

Finishing Well

NASA Astrophysics Data System (ADS)

Riendeau, Diane

2011-05-01

As we finish this publishing cycle, I'd like to thank all the readers who sent in video clips. If you have a YouTube clip that you use in class, please send the link and a brief description to driendeau@dist113.org.

Best of both worlds : clear exterior finishes : in search of finishes that protect wood without hiding its natural beauty

Treesearch

Tom Daniels; Marc Hirsch; Ken McClelland; Alan Ross; Sam Williams

2000-01-01

In recent years, a number of clear wood finishes have been developed that protect wood while accentuating its natural beauty. The focus of this publication is on those finishes having little visible pigment. In some cases, the pigments are included but are finely ground to create a coating that is transparent to visible light. Most natural clear wood finishes are...

Study on high-precision measurement of long radius of curvature

NASA Astrophysics Data System (ADS)

Wu, Dongcheng; Peng, Shijun; Gao, Songtao

2016-09-01

It is hard to get high-precision measurement of the radius of curvature (ROC), because of many factors that affect the measurement accuracy. For the measurement of long radius of curvature, some factors take more important position than others'. So, at first this paper makes some research about which factor is related to the long measurement distance, and also analyse the uncertain of the measurement accuracy. At second this article also study the influence about the support status and the adjust error about the cat's eye and confocal position. At last, a 1055micrometer radius of curvature convex is measured in high-precision laboratory. Experimental results show that the proper steady support (three-point support) can guarantee the high-precision measurement of radius of curvature. Through calibrating the gain of cat's eye and confocal position, is useful to ensure the precise position in order to increase the measurement accuracy. After finish all the above process, the high-precision long ROC measurement is realized.

Nanofabrication of ultra-low reflectivity black silicon surfaces and devices (Presentation Recording)

NASA Astrophysics Data System (ADS)

White, Victor E.; Yee, Karl Y.; Balasubramanian, Kunjithapatham; Echternach, Pierre M.; Muller, Richard E.; Dickie, Matthew R.; Cady, Eric; Ryan, Daniel J.; Eastwood, Michael; van Gorp, Byron; Riggs, A. J. Eldorado; Zimmerman, Niel; Kasdin, N. Jeremy

2015-08-01

Optical devices with features exhibiting ultra low reflectivity on the order of 10-7 specular reflectance in the visible spectrum are required for coronagraph instruments and some spectrometers employed in space research. Nanofabrication technologies have been developed to produce such devices with various shapes and feature dimensions to meet these requirements. Infrared reflection is also suppressed significantly with chosen wafers and processes. Particularly, devices with very high (>0.9) and very low reflectivity (<10-7) on adjacent areas have been fabricated and characterized. Significantly increased surface area due to the long needle like nano structures also provides some unique applications in other technology areas. We present some of the approaches, challenges and achieved results in producing and characterizing such devices currently employed in laboratory testbeds and instruments.

Ultra-low voltage electrowetting using graphite surfaces.

PubMed

Lomax, Deborah J; Kant, Pallav; Williams, Aled T; Patten, Hollie V; Zou, Yuqin; Juel, Anne; Dryfe, Robert A W

2016-10-26

The control of wetting behaviour underpins a variety of important applications from lubrication to microdroplet manipulation. Electrowetting is a powerful method to achieve external wetting control, by exploiting the potential-dependence of the liquid contact angle with respect to a solid substrate. Addition of a dielectric film to the surface of the substrate, which insulates the electrode from the liquid thereby suppressing electrolysis, has led to technological advances such as variable focal-length liquid lenses, electronic paper and the actuation of droplets in lab-on-a-chip devices. The presence of the dielectric, however, necessitates the use of large bias voltages (frequently in the 10-100 V range). Here we describe a simple, dielectric-free approach to electrowetting using the basal plane of graphite as the conducting substrate: unprecedented changes in contact angle for ultra-low voltages are seen below the electrolysis threshold (50° with 1 V for a droplet in air, and 100° with 1.5 V for a droplet immersed in hexadecane), which are shown to be reproducible, stable over 100 s of cycles and free of hysteresis. Our results dispel conventional wisdom that reversible, hysteresis-free electrowetting can only be achieved on solid substrates with the use of a dielectric. This work paves the way for the development of a new generation of efficient electrowetting devices using advanced materials such as graphene and monolayer MoS 2 .

Effect of Surface Treatments on Electron Beam Freeform Fabricated Aluminum Structures

NASA Technical Reports Server (NTRS)

Taminger, Karen M. B.; Hafley, Robert A.; Fahringer, David T.; Martin, Richard E.

2004-01-01

Electron beam freeform fabrication (EBF3) parts exhibit a ridged surface finish typical of many layer-additive processes. This, post-processing is required to produce a net shape with a smooth surface finish. High speed milling wire electrical discharge machining (EDM), electron beam glazing, and glass bead blasting were performed on EBF3-build 2219 aluminum alloy parts to reduce or eliminate the ridged surface features. Surface roughness, surface residual stress state, and microstructural characteristics were examined for each of the different surface treatment to assess the quality and effect of the surface treatments on the underlying material. The analysis evaluated the effectivenes of the different surface finishing techniques for achieving a smooth surface finish on an electron beam freeform fabricated part.

Low-loss integrated electrical surface plasmon source with ultra-smooth metal film fabricated by polymethyl methacrylate 'bond and peel' method.

PubMed

Liu, Wenjie; Hu, Xiaolong; Zou, Qiushun; Wu, Shaoying; Jin, Chongjun

2018-06-15

External light sources are mostly employed to functionalize the plasmonic components, resulting in a bulky footprint. Electrically driven integrated plasmonic devices, combining ultra-compact critical feature sizes with extremely high transmission speeds and low power consumption, can link plasmonics with the present-day electronic world. In an effort to achieve this prospect, suppressing the losses in the plasmonic devices becomes a pressing issue. In this work, we developed a novel polymethyl methacrylate 'bond and peel' method to fabricate metal films with sub-nanometer smooth surfaces on semiconductor wafers. Based on this method, we further fabricated a compact plasmonic source containing a metal-insulator-metal (MIM) waveguide with an ultra-smooth metal surface on a GaAs-based light-emitting diode wafer. An increase in propagation length of the SPP mode by a factor of 2.95 was achieved as compared with the conventional device containing a relatively rough metal surface. Numerical calculations further confirmed that the propagation length is comparable to the theoretical prediction on the MIM waveguide with perfectly smooth metal surfaces. This method facilitates low-loss and high-integration of electrically driven plasmonic devices, thus provides an immediate opportunity for the practical application of on-chip integrated plasmonic circuits.

High performance diesel oxidation catalysts using ultra-low Pt loading on titania nanowire array integrated cordierite honeycombs

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

Hoang, Son; Lu, Xingxu; Tang, Wenxiang

High performance of an ultra-low Pt loading diesel oxidation catalyst can be achieved by using a combination of novel nano-array structured support, precise control of ultrafine active Pt particles, and an addition of H 2 as a promoter into the exhausts. Highly stable mesoporous rutile TiO 2 nano-array was uniformly grown on three-dimensional (3-D) cordierite honeycomb monoliths using a solvothermal synthesis. Atomic layer deposition was employed for precise dispersion of ultrafine Pt particles (0.95 ± 0.24 nm) on TiO 2 nano-array with a Pt loading of 1.1 g/ft 3. Despite low Pt loading, the Pt/TiO 2 nano-array catalyst shows impressivemore » low-temperature oxidation reactivity, with the conversion of CO and total hydrocarbon (THC) reaching 50% at 224 and 285 °C, respectively, in the clean diesel combustion (CDC) simulated exhaust conditions. The excellent activity is attributed to the unique nano-array structure that promotes gas-solid interaction and ultra-small Pt particle dispersion that increase surface Pt atoms. We also demonstrate that addition of more H 2 into the exhaust can lower light-off temperature for CO and THC by up to ~60 °C and ~30 °C, respectively.« less

High performance diesel oxidation catalysts using ultra-low Pt loading on titania nanowire array integrated cordierite honeycombs

DOE PAGES

Hoang, Son; Lu, Xingxu; Tang, Wenxiang; ...

2017-11-15

High performance of an ultra-low Pt loading diesel oxidation catalyst can be achieved by using a combination of novel nano-array structured support, precise control of ultrafine active Pt particles, and an addition of H 2 as a promoter into the exhausts. Highly stable mesoporous rutile TiO 2 nano-array was uniformly grown on three-dimensional (3-D) cordierite honeycomb monoliths using a solvothermal synthesis. Atomic layer deposition was employed for precise dispersion of ultrafine Pt particles (0.95 ± 0.24 nm) on TiO 2 nano-array with a Pt loading of 1.1 g/ft 3. Despite low Pt loading, the Pt/TiO 2 nano-array catalyst shows impressivemore » low-temperature oxidation reactivity, with the conversion of CO and total hydrocarbon (THC) reaching 50% at 224 and 285 °C, respectively, in the clean diesel combustion (CDC) simulated exhaust conditions. The excellent activity is attributed to the unique nano-array structure that promotes gas-solid interaction and ultra-small Pt particle dispersion that increase surface Pt atoms. We also demonstrate that addition of more H 2 into the exhaust can lower light-off temperature for CO and THC by up to ~60 °C and ~30 °C, respectively.« less

Ultra-thin flexible GaAs photovoltaics in vertical forms printed on metal surfaces without interlayer adhesives

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

Kim, Juho; Song, Kwangsun; Kim, Namyun

2016-06-20

Wearable flexible electronics often require sustainable power sources that are also mechanically flexible to survive the extreme bending that accompanies their general use. In general, thinner microelectronic devices are under less strain when bent. This paper describes strategies to realize ultra-thin GaAs photovoltaics through the interlayer adhesiveless transfer-printing of vertical-type devices onto metal surfaces. The vertical-type GaAs photovoltaic devices recycle reflected photons by means of bottom electrodes. Systematic studies with four different types of solar microcells indicate that the vertical-type solar microcells, at only a quarter of the thickness of similarly designed lateral-type cells, generate a level of electric powermore » similar to that of thicker cells. The experimental results along with the theoretical analysis conducted here show that the ultra-thin vertical-type solar microcells are durable under extreme bending and thus suitable for use in the manufacturing of wearable flexible electronics.« less

High Precision Metrology on the Ultra-Lightweight W 50.8 cm f/1.25 Parabolic SHARPI Primary Mirror using a CGH Null Lens

NASA Technical Reports Server (NTRS)

Antonille, Scott

2004-01-01

For potential use on the SHARPI mission, Eastman Kodak has delivered a 50.8cm CA f/1.25 ultra-lightweight UV parabolic mirror with a surface figure error requirement of 6nm RMS. We address the challenges involved in verifying and mapping the surface error of this large lightweight mirror to +/-3nm using a diffractive CGH null lens. Of main concern is removal of large systematic errors resulting from surface deflections of the mirror due to gravity as well as smaller contributions from system misalignment and reference optic errors. We present our efforts to characterize these errors and remove their wavefront error contribution in post-processing as well as minimizing the uncertainty these calculations introduce. Data from Kodak and preliminary measurements from NASA Goddard will be included.

Model of the material removal function and an experimental study on a magnetorheological finishing process using a small ball-end permanent-magnet polishing head.

PubMed

Chen, Mingjun; Liu, Henan; Cheng, Jian; Yu, Bo; Fang, Zhen

2017-07-01

In order to achieve the deterministic finishing of optical components with concave surfaces of a curvature radius less than 10 mm, a novel magnetorheological finishing (MRF) process using a small ball-end permanent-magnet polishing head with a diameter of 4 mm is introduced. The characteristics of material removal in the proposed MRF process are studied. The model of the material removal function for the proposed MRF process is established based on the three-dimensional hydrodynamics analysis and Preston's equation. The shear stress on the workpiece surface is calculated by means of resolving the presented mathematical model using a numerical solution method. The analysis result reveals that the material removal in the proposed MRF process shows a positive dependence on shear stress. Experimental research is conducted to investigate the effect of processing parameters on the material removal rate and improve the surface accuracy of a typical rotational symmetrical optical component. The experimental results show that the surface accuracy of the finished component of K9 glass material has been improved to 0.14 μm (PV) from the initial 0.8 μm (PV), and the finished surface roughness Ra is 0.0024 μm. It indicates that the proposed MRF process can be used to achieve the deterministic removal of surface material and perform the nanofinishing of small curvature radius concave surfaces.

Effect of Pd Interlayer on Electrochemical Properties of ENIG Surface Finish in 3.5 wt.% NaCl Solution

NASA Astrophysics Data System (ADS)

Nam, N. D.; Bui, Q. V.; Nhan, H. T.; Phuong, D. V.; Bian, M. Z.

2014-09-01

The corrosion resistance of a multilayered (NiP-Pd-Au) coating with various thicknesses of palladium (Pd) interlayer deposited on copper by an electroless method was investigated using electrochemical techniques including potentiodynamic polarization and electrochemical impedance spectroscopy. In addition, the surface finish was examined by x-ray diffraction analysis and scanning electron microscopy, and the contact angle of the liquid-solid interface was recorded. The corrosion resistance of the copper substrate was considerably improved by Pd interlayer addition. Increase of the thickness of the Pd interlayer enhanced the performance of the Cu-NiP-Pd-Au coating due to low porosity, high protective efficiency, high charge-transfer resistance, and contact angle. These are attributed to the diffusion of layers in the Cu-NiP-Pd-Au coating acting as a physical barrier layer, leading to the protection provided by the coating.

The Role of Nanodiamonds in the Polishing Zone During Magnetorheological Finishing (MRF)

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

DeGroote, J.E.; Marino, A.E.; WIlson, J.P.

2008-01-07

In this work we discuss the role that nanodiamond abrasives play in magnetorheological finishing. We hypothesize that, as the nanodiamond MR fluid is introduced to the magnetic field, the micron sized spherical carbonyl iron (CI) particles are pulled down towards the rotating wheel, leaving a thin layer of nanodiamonds at the surface of the stiffened MR fluid ribbon. Our experimental results shown here support this hypothesis. We also show that surface roughness values inside MRF spots show a strong correlation with the near surface mechanical properties of the glass substrates and with drag force.

Plasma-deposited fluorocarbon polymer films on titanium for preventing cell adhesion: a surface finishing for temporarily used orthopaedic implants

NASA Astrophysics Data System (ADS)

Finke, B.; Testrich, H.; Rebl, H.; Walschus, U.; Schlosser, M.; Zietz, C.; Staehlke, S.; Nebe, J. B.; Weltmann, K. D.; Meichsner, J.; Polak, M.

2016-06-01

The design of a titanium implant surface should ideally support its later application in clinical use. Temporarily used implants have to fulfil requirements different from permanent implants: they should ensure the mechanical stabilization of the bone stock but in trauma surgery they should not be integrated into the bone because they will be removed after fracture healing. Finishing of the implant surface by a plasma-fluorocarbon-polymer (PFP) coating is a possible approach for preventing cell adhesion of osteoblasts. Two different low pressure gas-discharge plasma processes, microwave (MW 2.45 GHz) and capacitively coupled radio frequency (RF 13.56 MHz) plasma, were applied for the deposition of the PFP film using a mixture of the precursor octafluoropropane (C3F8) and hydrogen (H2). The thin films were characterized by x-ray photoelectron spectroscopy, Fourier transform infrared reflection absorption spectroscopy, and water contact angle measurements. Cell culture experiments show that cell adhesion and spreading of MG-63 osteoblasts were clearly reduced or nonexistent on these surfaces, also after 24 h of storage in the cell culture medium. In vivo data demonstrated that the local inflammatory tissue response for the PFP films deposited in MW and RF plasma were comparable to uncoated controls.

Note: High precision measurements using high frequency gigahertz signals

NASA Astrophysics Data System (ADS)

Jin, Aohan; Fu, Siyuan; Sakurai, Atsunori; Liu, Liang; Edman, Fredrik; Pullerits, Tõnu; Öwall, Viktor; Karki, Khadga Jung

2014-12-01

Generalized lock-in amplifiers use digital cavities with Q-factors as high as 5 × 108 to measure signals with very high precision. In this Note, we show that generalized lock-in amplifiers can be used to analyze microwave (giga-hertz) signals with a precision of few tens of hertz. We propose that the physical changes in the medium of propagation can be measured precisely by the ultra-high precision measurement of the signal. We provide evidence to our proposition by verifying the Newton's law of cooling by measuring the effect of change in temperature on the phase and amplitude of the signals propagating through two calibrated cables. The technique could be used to precisely measure different physical properties of the propagation medium, for example, the change in length, resistance, etc. Real time implementation of the technique can open up new methodologies of in situ virtual metrology in material design.

Analysis of performance and age of the fastest 100-mile ultra-marathoners worldwide.

PubMed

Rüst, Christoph Alexander; Knechtle, Beat; Rosemann, Thomas; Lepers, Romuald

2013-05-01

The performance and age of peak ultra-endurance performance have been investigated in single races and single race series but not using worldwide participation data. The purpose of this study was to examine the changes in running performance and the age of peak running performance of the best 100-mile ultra-marathoners worldwide. The race times and ages of the annual ten fastest women and men were analyzed among a total of 35,956 finishes (6,862 for women and 29,094 for men) competing between 1998 and 2011 in 100-mile ultra-marathons. The annual top ten performances improved by 13.7% from 1,132±61.8 min in 1998 to 977.6±77.1 min in 2011 for women and by 14.5% from 959.2±36.4 min in 1998 to 820.6±25.7 min in 2011 for men. The mean ages of the annual top ten fastest runners were 39.2±6.2 years for women and 37.2±6.1 years for men. The age of peak running performance was not different between women and men (p>0.05) and showed no changes across the years. These findings indicated that the fastest female and male 100-mile ultra-marathoners improved their race time by ∼14% across the 1998-2011 period at an age when they had to be classified as master athletes. Future studies should analyze longer running distances (>200 km) to investigate whether the age of peak performance increases with increased distance in ultra-marathon running.

A portable device for calibration of autocollimators with nanoradian precision

NASA Astrophysics Data System (ADS)

Yandayan, Tanfer

2017-09-01

A portable device has been developed in TUBITAK UME to calibrate high precision autocollimators with nanoradian precision. The device can operate in the range of +/-4500" which is far enough for the calibration of the available autocollimators and can generate ultra-small angles in measurement steps of 0.0005" (2.5 nrad). Description of the device with the performance tests using the calibrated precise autocollimators and novel methods will be reported. The test results indicate that the device is a good candidate for application to on-site/in-situ calibration of autocollimators with expanded uncertainties of 0.01" (50 nrad) particularly those used in slope measuring profilers.

Modeling of ultra-small lipid nanoparticle surface charge for targeting glioblastoma.

PubMed

Mendes, Maria; Miranda, Ana; Cova, Tânia; Gonçalves, Lídia; Almeida, António J; Sousa, João J; do Vale, Maria L C; Marques, Eduardo F; Pais, Alberto; Vitorino, Carla

2018-05-30

Surface modification of ultra-small nanostructured lipid carriers (usNLC) via introduction of a positive charge is hypothesized to prompt site-specific drug delivery for glioblastoma multiforme (GBM) treatment. A more effective interaction with negatively charged lipid bilayers, including the blood-brain barrier (BBB), will facilitate the nanoparticle access to the brain. For this purpose, usNLC with a particle size of 43.82 ± 0.03 nm and a polydispersity index of 0.224 were developed following a Quality by Design approach. Monomeric and gemini surfactants, either with conventional headgroups or serine-based ones, were tested for the surface modification, and the respective safety and efficacy to target GBM evaluated. A comprehensive in silico-in vitro approach is also provided based on molecular dynamics simulations and cytotoxicity studies. Overall, monomeric serine-derived surfactants displayed the best performance, considering altogether particle size, zeta potential, cytotoxic profile and cell uptake. Although conventional surfactants were able to produce usNLC with suitable physicochemical properties and cell uptake, their use is discouraged due to their high cytotoxicity. This study suggests that monomeric serine-derived surfactants are promising agents for developing nanosystems aiming at brain drug delivery. Copyright © 2018 Elsevier B.V. All rights reserved.

Low-loss integrated electrical surface plasmon source with ultra-smooth metal film fabricated by polymethyl methacrylate ‘bond and peel’ method

NASA Astrophysics Data System (ADS)

Liu, Wenjie; Hu, Xiaolong; Zou, Qiushun; Wu, Shaoying; Jin, Chongjun

2018-06-01

External light sources are mostly employed to functionalize the plasmonic components, resulting in a bulky footprint. Electrically driven integrated plasmonic devices, combining ultra-compact critical feature sizes with extremely high transmission speeds and low power consumption, can link plasmonics with the present-day electronic world. In an effort to achieve this prospect, suppressing the losses in the plasmonic devices becomes a pressing issue. In this work, we developed a novel polymethyl methacrylate ‘bond and peel’ method to fabricate metal films with sub-nanometer smooth surfaces on semiconductor wafers. Based on this method, we further fabricated a compact plasmonic source containing a metal-insulator-metal (MIM) waveguide with an ultra-smooth metal surface on a GaAs-based light-emitting diode wafer. An increase in propagation length of the SPP mode by a factor of 2.95 was achieved as compared with the conventional device containing a relatively rough metal surface. Numerical calculations further confirmed that the propagation length is comparable to the theoretical prediction on the MIM waveguide with perfectly smooth metal surfaces. This method facilitates low-loss and high-integration of electrically driven plasmonic devices, thus provides an immediate opportunity for the practical application of on-chip integrated plasmonic circuits.

Multifunctional ultra-high vacuum apparatus for studies of the interactions of chemical warfare agents on complex surfaces

NASA Astrophysics Data System (ADS)

Wilmsmeyer, Amanda R.; Gordon, Wesley O.; Davis, Erin Durke; Mantooth, Brent A.; Lalain, Teri A.; Morris, John R.

2014-01-01

A fundamental understanding of the surface chemistry of chemical warfare agents is needed to fully predict the interaction of these toxic molecules with militarily relevant materials, catalysts, and environmental surfaces. For example, rules for predicting the surface chemistry of agents can be applied to the creation of next generation decontaminants, reactive coatings, and protective materials for the warfighter. Here, we describe a multifunctional ultra-high vacuum instrument for conducting comprehensive studies of the adsorption, desorption, and surface chemistry of chemical warfare agents on model and militarily relevant surfaces. The system applies reflection-absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and mass spectrometry to study adsorption and surface reactions of chemical warfare agents. Several novel components have been developed to address the unique safety and sample exposure challenges that accompany the research of these toxic, often very low vapor pressure, compounds. While results of vacuum-based surface science techniques may not necessarily translate directly to environmental processes, learning about the fundamental chemistry will begin to inform scientists about the critical aspects that impact real-world applications.

Multifunctional ultra-high vacuum apparatus for studies of the interactions of chemical warfare agents on complex surfaces.

PubMed

Wilmsmeyer, Amanda R; Gordon, Wesley O; Davis, Erin Durke; Mantooth, Brent A; Lalain, Teri A; Morris, John R

2014-01-01

A fundamental understanding of the surface chemistry of chemical warfare agents is needed to fully predict the interaction of these toxic molecules with militarily relevant materials, catalysts, and environmental surfaces. For example, rules for predicting the surface chemistry of agents can be applied to the creation of next generation decontaminants, reactive coatings, and protective materials for the warfighter. Here, we describe a multifunctional ultra-high vacuum instrument for conducting comprehensive studies of the adsorption, desorption, and surface chemistry of chemical warfare agents on model and militarily relevant surfaces. The system applies reflection-absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and mass spectrometry to study adsorption and surface reactions of chemical warfare agents. Several novel components have been developed to address the unique safety and sample exposure challenges that accompany the research of these toxic, often very low vapor pressure, compounds. While results of vacuum-based surface science techniques may not necessarily translate directly to environmental processes, learning about the fundamental chemistry will begin to inform scientists about the critical aspects that impact real-world applications.

Multifunctional ultra-high vacuum apparatus for studies of the interactions of chemical warfare agents on complex surfaces

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

Wilmsmeyer, Amanda R.; Morris, John R.; Gordon, Wesley O.

2014-01-15

A fundamental understanding of the surface chemistry of chemical warfare agents is needed to fully predict the interaction of these toxic molecules with militarily relevant materials, catalysts, and environmental surfaces. For example, rules for predicting the surface chemistry of agents can be applied to the creation of next generation decontaminants, reactive coatings, and protective materials for the warfighter. Here, we describe a multifunctional ultra-high vacuum instrument for conducting comprehensive studies of the adsorption, desorption, and surface chemistry of chemical warfare agents on model and militarily relevant surfaces. The system applies reflection-absorption infrared spectroscopy, x-ray photoelectron spectroscopy, and mass spectrometry tomore » study adsorption and surface reactions of chemical warfare agents. Several novel components have been developed to address the unique safety and sample exposure challenges that accompany the research of these toxic, often very low vapor pressure, compounds. While results of vacuum-based surface science techniques may not necessarily translate directly to environmental processes, learning about the fundamental chemistry will begin to inform scientists about the critical aspects that impact real-world applications.« less

Ultra-localized single cell electroporation using silicon nanowires.

PubMed

Jokilaakso, Nima; Salm, Eric; Chen, Aaron; Millet, Larry; Guevara, Carlos Duarte; Dorvel, Brian; Reddy, Bobby; Karlstrom, Amelie Eriksson; Chen, Yu; Ji, Hongmiao; Chen, Yu; Sooryakumar, Ratnasingham; Bashir, Rashid

2013-02-07

Analysis of cell-to-cell variation can further the understanding of intracellular processes and the role of individual cell function within a larger cell population. The ability to precisely lyse single cells can be used to release cellular components to resolve cellular heterogeneity that might be obscured when whole populations are examined. We report a method to position and lyse individual cells on silicon nanowire and nanoribbon biological field effect transistors. In this study, HT-29 cancer cells were positioned on top of transistors by manipulating magnetic beads using external magnetic fields. Ultra-rapid cell lysis was subsequently performed by applying 600-900 mV(pp) at 10 MHz for as little as 2 ms across the transistor channel and the bulk substrate. We show that the fringing electric field at the device surface disrupts the cell membrane, leading to lysis from irreversible electroporation. This methodology allows rapid and simple single cell lysis and analysis with potential applications in medical diagnostics, proteome analysis and developmental biology studies.

Lawrence Livermore National Laboratory ULTRA-350 Test Bed

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

Hopkins, D J; Wulff, T A; Carlisle, K

2001-04-10

LLNL has many in-house designed high precision machine tools. Some of these tools include the Large Optics Diamond Turning Machine (LODTM) [1], Diamond Turning Machine No.3 (DTM-3) and two Precision Engineering Research Lathes (PERL-1 and PERL-11). These machines have accuracy in the sub-micron range and in most cases position resolution in the couple of nanometers range. All of these machines are built with similar underlying technologies. The machines use capstan drive technology, laser interferometer position feedback, tachometer velocity feedback, permanent magnet (PM) brush motors and analog velocity and position loop servo compensation [2]. The machine controller does not perform anymore » servo compensation it simply computes the differences between the commanded position and the actual position (the following error) and sends this to a D/A for the analog servo position loop. LLNL is designing a new high precision diamond turning machine. The machine is called the ULTRA 350 [3]. In contrast to many of the proven technologies discussed above, the plan for the new machine is to use brushless linear motors, high precision linear scales, machine controller motor commutation and digital servo compensation for the velocity and position loops. Although none of these technologies are new and have been in use in industry, applications of these technologies to high precision diamond turning is limited. To minimize the risks of these technologies in the new machine design, LLNL has established a test bed to evaluate these technologies for application in high precision diamond turning. The test bed is primarily composed of commercially available components. This includes the slide with opposed hydrostatic bearings, the oil system, the brushless PM linear motor, the two-phase input three-phase output linear motor amplifier and the system controller. The linear scales are not yet commercially available but use a common electronic output format. As of this writing, the

Lawrence Livermore National Laboratory ULTRA-350 Test Bed

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

Hopkins, D J; Wulff, T A; Carlisle, K

2001-04-10

LLNL has many in-house designed high precision machine tools. Some of these tools include the Large Optics Diamond Turning Machine (LODTM) [1], Diamond Turning Machine No.3 (DTM-3) and two Precision Engineering Research Lathes (PERL-I and PERL-II). These machines have accuracy in the sub-micron range and in most cases position resolution in the couple of nanometers range. All of these machines are built with similar underlying technologies. The machines use capstan drive technology, laser interferometer position feedback, tachometer velocity feedback, permanent magnet (PM) brush motors and analog velocity and position loop servo compensation [2]. The machine controller does not perform anymore » servo compensation it simply computes the differences between the commanded position and the actual position (the following error) and sends this to a D/A for the analog servo position loop. LLNL is designing a new high precision diamond turning machine. The machine is called the ULTRA 350 [3]. In contrast to many of the proven technologies discussed above, the plan for the new machine is to use brushless linear motors, high precision linear scales, machine controller motor commutation and digital servo compensation for the velocity and position loops. Although none of these technologies are new and have been in use in industry, applications of these technologies to high precision diamond turning is limited. To minimize the risks of these technologies in the new machine design, LLNL has established a test bed to evaluate these technologies for application in high precision diamond turning. The test bed is primarily composed of commercially available components. This includes the slide with opposed hydrostatic bearings, the oil system, the brushless PM linear motor, the two-phase input three-phase output linear motor amplifier and the system controller. The linear scales are not yet commercially available but use a common electronic output format. As of this writing, the

New-type steel plate with ultra high crack-arrestability

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

Ishikawa, T.; Nomiyama, Y.; Hagiwara, Y.

1995-12-31

A new-type steel plate has been developed by controlling the microstructure of the surface layers. The surface layer consists of ultra fine grain ferrite microstructure, which provides excellent fracture toughness even at cryogenic temperature. When an unstable brittle crack propagates in the developed steel plate, shear-lips can be easily formed due to the surface layers with ultra fine grain microstructure. Since unstable running crack behavior is strongly affected by side-ligaments (shear-lips), which are associated with extensive plastic deformation, enhanced formation of the shear-lips can improve crack arrestability. This paper describes the developed steel plates of HT500MPa tensile strength class formore » shipbuilding use. Fracture mechanics investigations using large-scale fracture testings (including ultrawide duplex ESSO tests) clarified that the developed steel plates have ultra high crack-arrestability. It was also confirmed that the plates possess sufficient properties, including weldability and workability, for ship building use.« less

Deterministic ion beam material adding technology for high-precision optical surfaces.

PubMed

Liao, Wenlin; Dai, Yifan; Xie, Xuhui; Zhou, Lin

2013-02-20

Although ion beam figuring (IBF) provides a highly deterministic method for the precision figuring of optical components, several problems still need to be addressed, such as the limited correcting capability for mid-to-high spatial frequency surface errors and low machining efficiency for pit defects on surfaces. We propose a figuring method named deterministic ion beam material adding (IBA) technology to solve those problems in IBF. The current deterministic optical figuring mechanism, which is dedicated to removing local protuberances on optical surfaces, is enriched and developed by the IBA technology. Compared with IBF, this method can realize the uniform convergence of surface errors, where the particle transferring effect generated in the IBA process can effectively correct the mid-to-high spatial frequency errors. In addition, IBA can rapidly correct the pit defects on the surface and greatly improve the machining efficiency of the figuring process. The verification experiments are accomplished on our experimental installation to validate the feasibility of the IBA method. First, a fused silica sample with a rectangular pit defect is figured by using IBA. Through two iterations within only 47.5 min, this highly steep pit is effectively corrected, and the surface error is improved from the original 24.69 nm root mean square (RMS) to the final 3.68 nm RMS. Then another experiment is carried out to demonstrate the correcting capability of IBA for mid-to-high spatial frequency surface errors, and the final results indicate that the surface accuracy and surface quality can be simultaneously improved.

Advanced zirconia-coated carbonyl-iron particles for acidic magnetorheological finishing of chemical-vapor-deposited ZnS and other IR materials

NASA Astrophysics Data System (ADS)

Salzman, S.; Giannechini, L. J.; Romanofsky, H. J.; Golini, N.; Taylor, B.; Jacobs, S. D.; Lambropoulos, J. C.

2015-10-01

We present a modified version of zirconia-coated carbonyl-iron (CI) particles that were invented at the University of Rochester in 2008. The amount of zirconia on the coating is increased to further protect the iron particles from corrosion when introduced to an acidic environment. Five low-pH, magnetorheological (MR) fluids were made with five acids: acetic, hydrochloric, nitric, phosphoric, and hydrofluoric. All fluids were based on the modified zirconia-coated CI particles. Off-line viscosity and pH stability were measured for all acidic MR fluids to determine the ideal fluid composition for acidic MR finishing of chemical-vapor-deposited (CVD) zinc sulfide (ZnS) and other infrared (IR) optical materials, such as hot-isostatic-pressed (HIP) ZnS, CVD zinc selenide (ZnSe), and magnesium fluoride (MgF2). Results show significant reduction in surface artifacts (millimeter-size, pebble-like structures on the finished surface) for several standard-grade CVD ZnS substrates and good surface roughness for the non-CVD MgF2 substrate when MR finished with our advanced acidic MR fluid.

Can We Improve the Tolerance of an Ocular Prosthesis by Enhancing Its Surface Finish?

PubMed

Litwin, Andre S; Worrell, Emma; Roos, Jonathan C P; Edwards, Barry; Malhotra, Raman

Patients who wear an ocular prosthesis frequently suffer with dry eye symptoms and socket discharge, often on a daily basis. The aim of the study was to determine whether a smoother, optical quality polish of the prosthesis' surface could improve symptoms and wear tolerance. The study was designed as single-center, single-masked, prospective randomized controlled trial. Eighty-eight consecutive patients undergoing annual ocular prosthesis maintenance review were approached from the prosthesis clinic. Forty-one out of 49 eligible patients were recruited. Participants were randomized to either a standard or a higher "optical quality" polish of their prosthesis. At entry to the trial, at 1 month, and 12 months they completed a questionnaire covering cleaning, lubricant use, inflammation, discomfort, and discharge. Lower scores indicated better tolerance of the prosthesis. At each visit, the prosthesis was stained and photographed against a standard background to assess deposit build up. Primary outcome measures were 1) a subjective questionnaire score and 2) an objective assessment of surface deposit build-up on prosthetic eyes by standardized photographic grading. Forty-one patients participated in the study. The median age of their prosthesis was 36 months (range 9 months-40 years). There was no statistically significant difference in questionnaire scores or deposit build up between the 2 groups at baseline. By 12-months, the higher optical quality polish showed a statistically significant reduction in symptoms and frequency of discharge (2.19 vs. 3.85; p = 0.05-lower scores better). Scoring of the prosthesis' deposit build-up showed a significant difference at 1 month, but this was not sustained at 12 months. Creating an optical quality finish to an ocular prosthesis reduces deposit build up on artificial eyes. The authors found this modification improved patient tolerance at 12 months.

An ultra-compact rejection filter based on spoof surface plasmon polaritons.

PubMed

Zhao, Shumin; Zhang, Hao Chi; Zhao, Jiahao; Tang, Wen Xuan

2017-09-05

In this paper, we propose a scheme to construct a new type of ultra-compact rejection filter by loading split-ring resonators (SRRs) on the transmission line of spoof surface plasmon polaritons (SPPs). From the dispersion analysis of the spoof SPP transmission line with and without the SRR loading, we clearly reveal the mechanism of the rejection characteristic for this compact filter. Meanwhile, we fabricate two spoof SPPs waveguides loaded with different amounts of metamaterials particles, and experimentally test them using an Agilent Vector Network Analyzer (VNA) and a homemade near-field scanning system. Both the simulated and measured results agree well with our theoretical analysis and demonstrate the excellent filtering characteristics of our design. The isolation of both filters can be less than -20 dB, and even reach -40 dB at rejection frequencies. The proposed rejection and stop-band filters show important potentials to develop integrated plasmonic functional devices and circuits at microwave and terahertz frequencies.

Surface modification of ultra thin PES-zeolite using thermal annealing to increase flux and rejection of produced water treatment

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

Kusworo, T. D., E-mail: tdkusworo@che.undip.ac.id; Widayat,; Pradini, A. W.

2015-12-29

Membrane technology is an alternative of water treatment based on filtration that is being developed. Surface Modification using heat treatment has been investigated to improve the performance of ultra thin PES-Zeolite nanocomposite membrane for produced water treatment from Pertamina Balongan. Two types of membranes with surface modification and without modification were prepared to study the effect of surface modification on its permeation properties. Asymmetric ultra thin PES-Zeolite nanocomposite membrane for produced water treatment was casted using the dry/wet phase inversion technique from dope solutions containing polyethersulfone, N-methyl-2-pyrrolidone (NMP) as a solvent and zeolite as a filler. Experimental results showed thatmore » the heat treatment at near glass transition temperature was increase the rejection of COD, Turbidity and ion Ca{sup 2+}. The better adherence of zeolite particles in the polymer matrix combined with formation of charge transfer complexes (CTCs) and cross-linking might be the main factors to enhance the percent of rejection. Field emission scanning electron microscopy (FESEM) micrographs showed that the selective layer and the substructure of PES-zeolite membrane became denser and more compact after the heat treatment. The FESEM micrographs also showed that the heat treatment was increased the adherence of zeolite particle and polymer. Membranes treated at 180 °C for 15 seconds indicated increase the rejection and small decrease in flux for produced water treatment.« less

Precision injection molding of freeform optics

NASA Astrophysics Data System (ADS)

Fang, Fengzhou; Zhang, Nan; Zhang, Xiaodong

2016-08-01

Precision injection molding is the most efficient mass production technology for manufacturing plastic optics. Applications of plastic optics in field of imaging, illumination, and concentration demonstrate a variety of complex surface forms, developing from conventional plano and spherical surfaces to aspheric and freeform surfaces. It requires high optical quality with high form accuracy and lower residual stresses, which challenges both optical tool inserts machining and precision injection molding process. The present paper reviews recent progress in mold tool machining and precision injection molding, with more emphasis on precision injection molding. The challenges and future development trend are also discussed.

Will women outrun men in ultra-marathon road races from 50 km to 1,000 km?

PubMed

Zingg, Matthias Alexander; Karner-Rezek, Klaus; Rosemann, Thomas; Knechtle, Beat; Lepers, Romuald; Rüst, Christoph Alexander

2014-01-01

It has been assumed that women would be able to outrun men in ultra-marathon running. The present study investigated the sex differences in running speed in ultra-marathons held worldwide from 50 km to 1,000 km. Changes in running speeds and the sex differences in running speeds in the annual fastest finishers in 50 km, 100 km, 200 km and 1,000 km events held worldwide from 1969-2012 were analysed using linear, non-linear and multi-level regression analyses. For the annual fastest and the annual ten fastest finishers, running speeds increased non-linearly in 50 km and 100 km, but not in 200 km and 1,000 km where running speeds remained unchanged for the annual fastest. The sex differences decreased non-linearly in 50 km and 100 km, but not in 200 and 1,000 km where the sex difference remained unchanged for the annual fastest. For the fastest women and men ever, the sex difference in running speed was lowest in 100 km (5.0%) and highest in 50 km (15.4%). For the ten fastest women and men ever, the sex difference was lowest in 100 km (10.0 ± 3.0%) and highest in 200 km (27.3 ± 5.7%). For both the fastest (r(2) = 0.003, p = 0.82) and the ten fastest finishers ever (r(2) = 0.34, p = 0.41) in 50 km, 100 km, 200 km and 1,000 km, we found no correlation between sex difference in performance and running speed. To summarize, the sex differences in running speeds decreased non-linearly in 50 km and 100 km but remained unchanged in 200 km and 1,000 km, and the sex differences in running speeds showed no change with increasing length of the race distance. These findings suggest that it is very unlikely that women will ever outrun men in ultra-marathons held from 50 km to 100 km.

Methods for improving the damage performance of fused silica polished by magnetorheological finishing