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Sample records for fabrication techniques producing

  1. Semiconductor fabrication techniques for producing an ultra-flat reflective slit

    NASA Astrophysics Data System (ADS)

    Vandervelde, Thomas E.; Cabral, Michael J.; Wilson, John; Skrutskie, Michael

    2006-06-01

    The most difficult aspects in manufacturing a reflective slit substrate are achieving a precisely fabricated slit surrounded by an optically flat surface. A commonly used technique is to polish a metal substrate that has a slit cut by electric discharge machine (EDM) methods. This process can produce 'optically flat' surfaces; however, the EDM can produce a slit with edge roughness on the order of 10 microns and a RMS field roughness of ~1 micron. Here, we present a departure from these traditional methods and employ the advantages inherent in integrated circuit fabrication. By starting with a silicon wafer, we begin with a nearly atomically flat surface. In addition, the fabrication tools and methodologies employed are traditionally used for high precision applications: this allows for the placement and definition of the slit with high accuracy. If greater accuracy in slit definition is required, additional tools, such as a focused ion beam, are used to define the slit edge down to tens of nanometers. The deposition of gold, after that of a suitable bonding layer, in an ultra-high vacuum chamber creates a final surface without the need of polishing. Typical results yield a surface RMS-roughness of approximately 2nm. Most of the techniques and tools required for this process are commonly available at research universities and the cost to manufacture said mirrors is a small fraction of the purchase price of the traditional ones.

  2. Techniques of Electrode Fabrication

    NASA Astrophysics Data System (ADS)

    Guo, Liang; Li, Xinyong; Chen, Guohua

    Electrochemical applications using many kinds of electrode materials as an advanced oxidation/reduction technique have been a focus of research by a number of groups during the last two decades. The electrochemical approach has been adopted successfully to develop various environmental applications, mainly including water and wastewater treatment, aqueous system monitoring, and solid surface analysis. In this chapter, a number of methods for the fabrication of film-structured electrode materials were selectively reviewed. Firstly, the thermal decomposition method is briefly described, followed by introducing chemical vapor deposition (CVD) strategy. Especially, much attention was focused on introducing the methods to produce diamond novel film electrode owing to its unique physical and chemical properties. The principle and influence factors of hot filament CVD and plasma enhanced CVD preparation were interpreted by refereeing recent reports. Finally, recent developments that address electro-oxidation/reduction issues and novel electrodes such as nano-electrode and boron-doped diamond electrode (BDD) are presented in the overview.

  3. Nozzle fabrication technique

    NASA Technical Reports Server (NTRS)

    Wells, Dennis L. (Inventor)

    1991-01-01

    A block of electrically conductive material which is to be formed into a body with internal and/or external surfaces that approximate hyperboloids of one sheet is placed so that its axis is set at a predetermined skew angle with relation to a traveling EDM electrode wire. The electrode wire is then moved into cutting proximity of the body wire. Thereafter, by revolving the body about its own axis, the external and/or internal surfaces of the body will be cut into an approximate hyperbolic surface of revolution depending upon whether the body is positioned with the cutting wire outside of the body or in a previously formed longitudinal passage in the body. As an alternative technique, elongated channels can also be cut into the wall of the body by successively orienting the body to a selected number of angular positions, with the electrode wire being either outside of the body or in a previously formed passage in the body. At each of these angular positions, the electrode wire is moved orthogonally with respect to the axis of the wire, while both the body axis skew angle and the rotational position about that axis is controlled by cutting a channel or groove in the body to relieve stresses in the body material or to convey a coolant fluid.

  4. Nozzle fabrication technique

    NASA Technical Reports Server (NTRS)

    Wells, Dennis L. (Inventor)

    1989-01-01

    A block of electrically-conductive material which is to be formed into a body with internal and/or external surfaces that approximate hyperboloids of one sheet is placed so that its axis is set at a predetermined skew angle with relation to a travelling EDM electrode wire and the electrode wire is then moved into cutting proximity of the body. Thereafter, by revolving the body about its own axis, the external and/or internal surfaces of the body will be cut into an approximate hyperbolic surface of revolution depending upon whether the body is positioned with the cutting wire outside of the body or in a previously-formed longitudinal passage in the body. As an alternative technique, elongated channels can also be cut into the walls of the body by successively orienting the body to a selected number of angular positions with the electrode wire being either outside of the body or in a previously-formed passage in the body. At each of these angular positions, the electrode wire is moved orthogonally with respect to the axis of the wire while both the body axis skew angle and the rotational position about that axis are controlled for cutting a channel or groove in the body as required to relieve stresses in the material of the body or to convey a coolant fluid.

  5. Micro-fabrication Techniques for Target Components

    SciTech Connect

    Miles, R; Hamilton, J; Crawford, J; Ratti, S; Trevino, J; Graff, T; Stockton, C; Harvey, C

    2008-06-10

    Micro-fabrication techniques, derived from the semi-conductor industry, can be used to make a variety of useful mechanical components for targets. A selection of these components including supporting cooling arms for prototype cryogenic inertial confinement fusion targets, stepped and graded density targets for materials dynamics experiments are described. Micro-fabrication enables cost-effective, simultaneous fabrication of multiple high-precision components with complex geometries. Micro-fabrication techniques such as thin-film deposition, photo-lithographic patterning and etch processes normally used in the semi-conductor manufacture industry, can be exploited to make useful mechanical target components. Micro-fabrication processes have in recent years been used to create a number of micro-electro-mechanical systems (MEMS) components such as pressure sensors, accelerometers, ink jet printer heads, microfluidics platforms and the like. These techniques consist primarily of deposition of thin films of material, photo-lithographic patterning and etching processes performed sequentially to produce three dimensional structures using essentially planar processes. While the planar technology can be limiting in terms of the possible geometries of the final product, advantages of using these techniques include the ability to make multiple complex structures simultaneously and cost-effectively. Target components fabricated using these techniques include the supporting cooling arms for cryogenic prototype fusion ignition targets, stepped targets for equation-of-state experiments, and graded density reservoirs for material strength experiments.

  6. A standardized block fabrication technique

    SciTech Connect

    Famiglietti, R.; Noriega, B.; Sanders, R. )

    1990-01-01

    The accuracy of delivered dose is a primary goal in every radiation therapy department. Improved imaging techniques now enable the radiation therapist to define more precisely the area of interest, which helps the sparing of normal surrounding tissue. Tray-mounted customized blocks are routinely used to define this treatment portal accurately and reproducibly. However, the level of accuracy is dependent on the block fabrication technique and the skill of the block cutter. We at Moffitt Cancer Center have standardized our system in a way that minimizes some of the human errors, while keeping the procedure fast and accurate. This system uses a tray template that simulates our blocking trays. The function of this tray is to position the styrofoam (and therefore the cerrobend block) on the tray in such a way as to insure proper alignment with the treatment machine. We also feel this improves upon some common designs using random holes or hole patterns, which may interfere with the treatment area. This system is not overly sophisticated and can be easily implemented in most radiation therapy departments.

  7. Fabrication techniques for very fast diffractive lenses

    NASA Technical Reports Server (NTRS)

    Tai, Anthony M.; Marron, Joseph C.

    1993-01-01

    Aspheric lenses with arbitrary phase functions can be fabricated on thin light weight substrates via the binary optics fabrication technique. However, it is difficult and costly to fabricate a fast lens (f/number less than 1) for use as the shorter wavelengths. The pitch of the masks and the alignment accuracy must be very fine. For a large lens, the space-bandwidth product of the element can also become impractically large. In this paper, two alternate approaches for the fabrication of fast aspheric diffractive lenses are described. The first approach fabricates the diffractive lens interferometrically, utilizing a spherical wavefront to provide the optical power of the lens and a computer generated hologram to create the aspheric components. The second approach fabricates the aspheric diffractive lens in the form if a higher order kinoform which trades groove profile fidelity for coarser feature size. The design and implementation issues for these two fabrication techniques are discussed.

  8. Characterization of 2219 Aluminum Produced by Electron Beam Freeform Fabrication

    NASA Technical Reports Server (NTRS)

    Taminger, Karen M. B.; Hafley, Robert A.

    2002-01-01

    Researchers at NASA Langley Research Center are developing a new electron beam freeform fabrication (EB F(sup 3)) technique to fabricate metal parts. This process introduces metal wire into a molten pool created by a focused electron beam. Potential aerospace applications for this technology include ground-based fabrication of airframe structures and on-orbit construction and repair of space components and structures. Processing windows for reliably producing high quality 2219 aluminum parts using the EB F(sup 3) technique are being defined. The effects of translation speed, wire feed rate, and beam power on the resulting microstructures and mechanical properties are explored. Tensile properties (ultimate tensile strength, yield strength, and elongation) show little effect over the range of processing conditions tested. Basic processing-microstructure-property correlations are drawn for the EB F(sup 3) process.

  9. Fabrication techniques for superconducting readout loops

    NASA Technical Reports Server (NTRS)

    Payne, J. E.

    1982-01-01

    Procedures for the fabrication of superconducting readout loops out of niobium on glass substrates were developed. A computer program for an existing fabrication system was developed. Both positive and negative resist procedures for the production of the readout loops were investigated. Methods used to produce satisfactory loops are described and the various parameters affecting the performance of the loops are analyzed.

  10. A photolithographic fabrication technique for magnetohydrodynamic micropumps

    NASA Astrophysics Data System (ADS)

    Kuenstner, Stephen; Baylor, Martha-Elizabeth

    2014-03-01

    Magnetohydrodynamic (MHD) devices use perpendicular electric and magnetic fields to exert a Lorentz body force on a conducting fluid. Miniaturized MHD devices have been used to create pumps, stirrers, heat exchangers, and microfluidic networks. Compared to mechanical micropumps, MHD micropumps are appealing because they require no moving parts, which simplifies fabrication, and because they are amenable to electronic control. This abstract reports the fabrication and testing of a centimeter-scale MHD pump using a thiol-ene/methacrylate-based photopolymer and mask-based photolithographic technique. Pumps like this one could simplify the fabrication of sophisticated optofluidic devices, including liquid-core, liquid cladding (L2) waveguides, which are usually created with PDMS using stamps, or etched into silicon wafers. The photolithographic technique demonstrated here requires only one masking step to create fluid channels with complex geometries.

  11. Technology development of fabrication techniques for advanced solar dynamic concentrators

    NASA Technical Reports Server (NTRS)

    Richter, Scott W.

    1991-01-01

    The objective of the advanced concentrator program is to develop the technology that will lead to lightweight, highly reflective, accurate, scaleable, and long lived space solar dynamic concentrators. The advanced concentrator program encompasses new and innovative concepts, fabrication techniques, materials selection, and simulated space environmental testing. Fabrication techniques include methods of fabricating the substrates and coating substrate surfaces to produce high-quality optical surfaces, acceptable for further coating with vapor deposited optical films. The selected materials to obtain a high quality optical surface include microsheet glass and Eccocoat EP-3 epoxy, with DC-93-500 selected as a candidate silicone adhesive and levelizing layer. The following procedures are defined: cutting, cleaning, forming, and bonding microsheet glass. Procedures are also defined for surface cleaning, and EP-3 epoxy application. The results and analyses from atomic oxygen and thermal cycling tests are used to determine the effects of orbital conditions in a space environment.

  12. Technology development of fabrication techniques for advanced solar dynamic concentrators

    NASA Technical Reports Server (NTRS)

    Richter, Scott W.

    1991-01-01

    The objective of the advanced concentrator program is to develop the technology that will lead to lightweight, highly reflective, accurate, scaleable, and long lived space solar dynamic concentrators. The advanced concentrator program encompasses new and innovative concepts, fabrication techniques, materials selection, and simulated space environmental testing. Fabrication techniques include methods of fabricating the substrates and coating substrate surfaces to produce high quality optical surfaces, acceptable for further coating with vapor deposited optical films. The selected materials to obtain a high quality optical surface include microsheet glass and Eccocoat EP-3 epoxy, with DC-93-500 selected as a candidate silicone adhesive and levelizing layer. The following procedures are defined: cutting, cleaning, forming, and bonding microsheet glass. Procedures are also defined for surface cleaning, and EP-3 epoxy application. The results and analyses from atomic oxygen and thermal cycling tests are used to determine the effects of orbital conditions in a space environment.

  13. Investigation of electroforming techniques. [fabrication of regeneratively cooled thrust chambers

    NASA Technical Reports Server (NTRS)

    Malone, G. A.

    1975-01-01

    Copper and nickel electroforming was examined for the purpose of establishing the necessary processes and procedures for repeatable, successful fabrication of the outer structures of regeneratively cooled thrust chambers. The selection of electrolytes for copper and nickel deposition is described. The development studies performed to refine and complete the processes necessary for successful chamber shell fabrication and the testing employed to verify the applicability of the processes and procedures to small scale hardware are described. Specifications were developed to afford a guideline for the electroforming of high quality outer shells on regeneratively cooled thrust chamber liners. Test results indicated repeatable mechanical properties could be produced in copper deposits from the copper sulfate electrolyte with periodic current reversal and in nickel deposits from the sulfamate solution. Use of inert, removable channel fillers and the conductivizing of such is described. Techniques (verified by test) which produce high integrity bonds to copper and copper alloy liners are discussed.

  14. High volume fabrication of laser targets using MEMS techniques

    NASA Astrophysics Data System (ADS)

    Spindloe, C.; Arthur, G.; Hall, F.; Tomlinson, S.; Potter, R.; Kar, S.; Green, J.; Higginbotham, A.; Booth, N.; Tolley, M. K.

    2016-04-01

    The latest techniques for the fabrication of high power laser targets, using processes developed for the manufacture of Micro-Electro-Mechanical System (MEMS) devices are discussed. These laser targets are designed to meet the needs of the increased shot numbers that are available in the latest design of laser facilities. Traditionally laser targets have been fabricated using conventional machining or coarse etching processes and have been produced in quantities of 10s to low 100s. Such targets can be used for high complexity experiments such as Inertial Fusion Energy (IFE) studies and can have many complex components that need assembling and characterisation with high precision. Using the techniques that are common to MEMS devices and integrating these with an existing target fabrication capability we are able to manufacture and deliver targets to these systems. It also enables us to manufacture novel targets that have not been possible using other techniques. In addition, developments in the positioning systems that are required to deliver these targets to the laser focus are also required and a system to deliver the target to a focus of an F2 beam at 0.1Hz is discussed.

  15. 48 CFR 252.236-7013 - Requirement for competition opportunity for American steel producers, fabricators, and...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... competition opportunity for American steel producers, fabricators, and manufacturers. 252.236-7013 Section 252....236-7013 Requirement for competition opportunity for American steel producers, fabricators, and... for American Steel Producers, Fabricators, and Manufacturers (JUN 2013) (a) Definition....

  16. 48 CFR 252.236-7013 - Requirement for competition opportunity for American steel producers, fabricators, and...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... competition opportunity for American steel producers, fabricators, and manufacturers. 252.236-7013 Section 252....236-7013 Requirement for competition opportunity for American steel producers, fabricators, and... for American Steel Producers, Fabricators, and Manufacturers (JAN 2009) (a) Definition....

  17. 48 CFR 252.236-7013 - Requirement for competition opportunity for american steel producers, fabricators, and...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... competition opportunity for american steel producers, fabricators, and manufacturers. 252.236-7013 Section 252....236-7013 Requirement for competition opportunity for american steel producers, fabricators, and... FOR AMERICAN STEEL PRODUCERS, FABRICATORS, AND MANUFACTURERS (JAN 2009) (a) Definition....

  18. 48 CFR 252.236-7013 - Requirement for competition opportunity for american steel producers, fabricators, and...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... competition opportunity for american steel producers, fabricators, and manufacturers. 252.236-7013 Section 252....236-7013 Requirement for competition opportunity for american steel producers, fabricators, and... FOR AMERICAN STEEL PRODUCERS, FABRICATORS, AND MANUFACTURERS (JAN 2009) (a) Definition....

  19. 48 CFR 252.236-7013 - Requirement for competition opportunity for American steel producers, fabricators, and...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... competition opportunity for American steel producers, fabricators, and manufacturers. 252.236-7013 Section 252....236-7013 Requirement for competition opportunity for American steel producers, fabricators, and... for American Steel Producers, Fabricators, and Manufacturers (JUN 2013JAN 2009) (a)...

  20. Development of a Direct Fabrication Technique for Full-Shell X-Ray Optics

    NASA Technical Reports Server (NTRS)

    Gubarev, M.; Kolodziejczak, J. K.; Griffith, C.; Roche, J.; Smith, W. S.; Kester, T.; Atkins, C.; Arnold, W.; Ramsey, B.

    2016-01-01

    Future astrophysical missions will require fabrication technology capable of producing high angular resolution x-ray optics. A full-shell direct fabrication approach using modern robotic polishing machines has the potential for producing high resolution, light-weight and affordable x-ray mirrors that can be nested to produce large collecting area. This approach to mirror fabrication, based on the use of the metal substrates coated with nickel phosphorous alloy, is being pursued at MSFC. The design of the polishing fixtures for the direct fabrication, the surface figure metrology techniques used and the results of the polishing experiments are presented.

  1. Design for producing fiberglass fabric in a lunar environment

    NASA Technical Reports Server (NTRS)

    Dorrity, J. Lewis; Patel, Suneer; Benson, Rafer M.; Johnson, Michael C.; Storey, Mark A.; Tran, Dai T.; Zahr, Thomas A.; Causby, Dana R.

    1992-01-01

    The purpose of this project was to design a method of producing a fabric material on the lunar surface from readily available glass fibers. Various methods for forming fabrics were analyzed to determine which methods were appropriate for the lunar conditions. A nonwoven process was determined to be the most suitable process for making a fabric material out of fiberglass under these conditions. Various resins were considered for adhering the fibers. A single thermoplastic resin (AURUM) was found to be the only applicable resin. The end product of the process was determined to be suitable for use as a roadway surfacing material, canopy materials, reflective material, or packaging material. A cost analysis of the lunar process versus shipping the end-product from the earth suggests that the lunar formation is highly feasible. A design for a lunar, nonwoven process was determined and included in the following document.

  2. Design for producing fiberglass fabric in a lunar environment

    NASA Technical Reports Server (NTRS)

    Benson, Rafer M.; Causby, Dana R.; Johnson, Michael C.; Storey, Mark A.; Tran, Dal T.; Zahr, Thomas A.

    1992-01-01

    The purpose of this project was to design a method of producing a fabric material on the lunar surface from readily available glass fibers. Various methods for forming fabrics were analyzed to determine which methods were appropriate for the lunar conditions. A nonwoven process was determined to be the most suitable process for making a fabric material out of fiberglass under these conditions. Various resins were considered for adhering the fibers. A single thermoplastic resin (AURUM) was found to be the only applicable resin. The end product of the process was determined to be suitable for use as a roadway surfacing material, canopy material, reflective material, or packaging material. A cost analysis of the lunar process versus shipping the end-product from the Earth suggests that the lunar formation is highly feasible. A design for a lunar, nonwoven process was determined and is included.

  3. Improved fabrication techniques for infrared bolometers

    NASA Technical Reports Server (NTRS)

    Lange, A. E.; Kreysa, E.; Mcbride, S. E.; Richards, P. L.; Haller, E. E.

    1983-01-01

    Techniques are described for producing improved infrared bolometers from doped germanium. Ion implantation and sputter metalization have been used to make ohmic electrical contacts to Ge:Ga chips. This method results in a high yield of small monolithic bolometers with very little low-frequency noise. When one of these chips is used as the thermometric element of a composite bolometer, it must be bonded to a dielectric substrate. The thermal resistance of the conventional epoxy bond has been measured and found to be undesirably large. A procedure for soldering the chip to a metalized portion of the substrate is described which reduced this resistance. The contribution of the metal film absorber to the heat capacity of a composite bolometer has been measured. The heat capacity of a NiCr absorber at 1.3 K can dominate the bolometer performance. A Bi absorber has significantly lower heat capacity. A low temperature blackbody calibrator has been built to measure the optical responsivity of bolometers. A composite bolometer system with a throughput of approx. 0.1 sr sq cm was constructed using the new techniques. In negligible background it has an optical NEP of 3.6 10((exp -15) W/sq root of Hz at 1.0 K with a time constant of 20 ms. The noise in this bolometer is white above 2.5 Hz and is somewhat below the value predicted by thermodynamic equilibrium theory. It is in agreement with calculations based on a recent nonequilibrium theory.

  4. Electromagnetic levitation coil fabrication technique for MSFC containerless processing facilities

    NASA Technical Reports Server (NTRS)

    Ethridge, E. C.; Theiss, J.; Curreri, P. A.; Abbaschian, G. J.

    1983-01-01

    A technique is described for more reproducible fabrication of electromagnetic levitation coils. A split mandrel was developed upon which the coil is wound. After fabrication the mandrel can be disassembled to remove it from the coil. Previously, a full day was required to fabricate a levitation coil and the success rate for a functional coil was only 50 percent. About eight coils may be completed in one day using the technique developed and 95 percent of them are good levitation coils.

  5. Fabrication techniques developed for small- diameter, thin-wall tungsten and tungsten alloy tubing

    NASA Technical Reports Server (NTRS)

    Brillhart, D. C.; Burt, W. R.; Karasek, F. J.; Mayfield, R. M.

    1968-01-01

    Report describes methods for the fabrication of tungsten and tungsten alloys into small-diameter, thin-wall tubing of nuclear quality. The tungsten, or tungsten alloy tube blanks are produced by double extrusion. Plug-drawing has emerged as an excellent secondary fabrication technique for the reduction of the overall tube dimensions.

  6. Fabrication of special ICF targets using a depolymerizable mandrel technique

    SciTech Connect

    Letts, S.A.; Fearon, E.M.; Allison, L.M.; Cook, R.

    1995-10-02

    A technique was developed for fabricating Spherical shell targets for implosion physics experiments with diameters up to several millimeters and with unique structural features such as thin metal layers or texture on the inside surface. We start with a spherical bead or thin shell of poly(alpha-methylstyrene) (PAMS) of the desired size, which can be textured by laser photoablation or overcoated with a thin layer of diagnostic material. The mandrel is next overcoated with plasma polymer (CH) 2 to 50 {mu}m thick. Upon heating, the PAMS depolymerizes to gaseous monomer which diffuses through the thermally stable plasma polymer coating leaving a hollow shell. Shells produced by this technique are uniform in wall thickness, and highly spherical. If the PAMS mandrel is textured, the mandrel topology is transferred to the inner wall of the plasma polymer shell. Likewise thermally stable coatings on the mandrel are transferred to the inner shell wall.

  7. Mirror substrate fabrication techniques of low expansion glasses.

    NASA Astrophysics Data System (ADS)

    Spangenberg-Jolley, J.; Hobbs, T.

    Low expansion glasses offer many advantages as mirror blank materials due to their thermal and mechanical properties as well as the flexibility they offer in design and fabrication. Fused Silica, Corning Code 7940 and ULETM titanium silicate, Code 7971, produced by the flame hydrolysis process, are high purity and homogeneous glasses. The ability to fusion seal each of the glasses offers mirror manufacturing design freedom of shape, size and weight. Solid monolithic mirror blanks have been successfully manufactured by the hex-seal method up to 4 meters diameter and 10 meter blanks are an extension of the proven fusion techniques. Ultralightweight (10% solid weight) low expansion mirrors produced by "frit bonding" a fusion core between two precision machined plates, maintain an optical figure when exposed to thermal cycling and mechanical abuse environments.

  8. Improved fabrication techniques for infrared bolometers

    NASA Technical Reports Server (NTRS)

    Lange, A. E.; Mcbride, S. E.; Richards, P. L.; Haller, E. E.; Kreysa, E.

    1983-01-01

    Ion implantation and sputter metallization are used to produce ohmic electrical contacts to Ge:Ga chips. The method is shown to give a high yield of small monolithic bolometers with very little low-frequency noise. It is noted that when one of the chips is used as the thermometric element of a composite bolometer it must be bonded to a dielectric substrate. The thermal resistance of the conventional epoxy bond is measured and found to be undesirably large. A procedure for soldering the chip to a metallized portion of the substrate in such a way as to reduce this resistance is outlined. An evaluation is made of the contribution of the metal film absorber to the heat capacity of a composite bolometer. It is found that the heat capacity of a NiCr absorber at 1.3 K can dominate the bolometer performance. A Bi absorber possesses significantly lower heat capacity. A low-temperature blackbody calibrator is built to measure the optical responsivity of bolometers. A composite bolometer system with a throughput of approximately 0.1 sr sq cm is constructed using the new techniques. The noise in this bolometer is white above 2.5 Hz and is slightly below the value predicted by thermodynamic equilibrium theory.

  9. Development of novel piezoelectric composites by solid freeform fabrication techniques

    NASA Astrophysics Data System (ADS)

    Panda, Rajesh Kumar

    Piezoelectric ceramic/polymer composites have been widely used for ultrasonic transducers because of their superior properties as compared to bulk piezoceramics or polymers. The electromechanical Properties of the composites can be tailored for various applications by changing the design and connectivity of the piezoceramic skeleton. The goal of this project was to utilize the design flexibility provided by solid freeform fabrication (SFF) techniques to manufacture complex PZT composite transducers for ultrasonic medical imaging applications. The ceramic element shape, size and spatial arrangement could be varied easily; by changing the parameters in the input computer aided design file. Many SFF techniques, including fused deposition modeling (FDM), fused deposition of ceramics (FDC), and Sanders prototyping (SP) were used to fabricate a variety of novel PZT structures. The composites were processed either by a direct, indirect or multiple mold route. In the direct route (FDC), green ceramic preforms were produced from 52 vol.% PZT-5H ceramic loaded polymer filaments. A lost mold technique was used for the indirect and multiple mold routes (SP, FDM). After heat treatment, the sintered PZT skeletons were backfilled with epoxy, polished, electroded and corona poled. A variety of novel and complex designs such as 3-D Honeycomb, 3-D Mesh, ladder, oriented fibers, 1-3 regular and staggered rods, and other composites including concentric polygon, hexagonal patterns, and 2-2 sheets with and without volume fraction gradient (VFG) were fabricated. The 3-D Honeycomb structures with a 3-3 connectivity showed d33 coefficients as high as 340 pC/N. The ladder structure exhibited distinctly different properties when poled along different directions. One of them, i.e. the oriented 3-3 fiber structure was believed to utilize the d33, d31 and d15 coefficients to show an effective d33 of 510 pC/N. VFG composites were fabricated to achieve a reduction the side and grating lobe

  10. Mirror Substrate Fabrication Techniques Of Low Expansion Glasses

    NASA Astrophysics Data System (ADS)

    Spangenberg-Jolley, J.; Hobbs, T.

    1989-01-01

    Low expansion glasses offer many advantages as mirror blank materials due to their thermal and mechanical properties as well as the flexility they offer in design and fabrication. Fused Silica, Corning Code 7940 and ULE titanium silicate, Code 7971, produced by the flame hydrolysis process, are high purity and homogeneous glasses. Determination of the average and the variation pattern of ghe Coefficient of thermal expansion (CTE) within ULE mirror blanks (nominally 0 x 10 /°C over the 5°C to 35°C temperature interval) is readily accomplished to an accuracy of + 2 parts per billion per degree centigrade (ppb/°C) by ultrasonic measurements. The ability to fusion seal each of the glasses offers mirror manufacturing design freedom of shape, size and weight. Solid monolithic mirror blanks have been successfully manufactured by the hex-seal method up to 4 meters diameter and 10 meter blanks are an extension of the proven fusion techniques. Lightweight fusion bonded ULE mirrors, such as the primary used in the Hubble Space Telescope, are fabricated by first "welding" selected glass pieces together to form a structurally rigid core and then fusing it between two plates. Ultralightweight (10% solid weight) low expansion mirrors produced by "frit bonding" a fusion core between two precision machined plates, maintain an optical figure when exposed to thermal cycling and mechanical abuse environments.

  11. Composite material fabrication techniques. CRADA final report

    SciTech Connect

    Frame, B J; Paulauskas, F L; Miller, J; Parzych, W

    1996-09-30

    This report describes a low cost method of fabricating components for mockups and training simulators used in the transportation industry. This technology was developed jointly by the Oak Ridge National Laboratory (ORNL) and Metters Industries, Incorporated (MI) as part of a Cooperative Research and Development Agreement (CRADA) ORNL94-0288 sponsored by the Department of Energy (DOE) Office of Economic Impace and Diversity Minority Business Technology Transfer Consortium. The technology involves fabricating component replicas from fiberglass/epoxy composites using a resin transfer molding (RTM) process. The original components are used as masters to fabricate the molds. The molding process yields parts that duplicate the significant dimensional requirements of the original component while still parts that duplicate the significant dimensional requirements of the original component while still providing adequate strength and stiffness for use in training simulators. This technology permits MI to overcome an acute shortage in surplus military hardware available to them for use in manufacturing training simulators. In addition, the cost of the molded fiberglass components is expected to be less than that of procuring the original components from the military.

  12. Superconducting lead particles produced by chemical techniques

    SciTech Connect

    Fariss, T.L.; Nixon, W.E.; Bucelot, T.J.; Deaver, B.S. Jr.; Mitchell, J.W.

    1982-09-01

    The superconductivity of extremely small lead particles has been studied as a function of size, surface condition, and connectivity using chemical techniques to produce particles of well-controlled size and shape suspended in insulating media. Approximately monodisperse suspensions of equiaxed, rod, and lath-shaped particles of lead halides and other lead compounds suspended in gelatin, polyacrylamide, polyvinylpyrrolidone, polyvinyl alcohol, methyl cellulose, and hydroxyethyl cellulose have been produced. These particles have been reduced to pseudomorphs of lead in the liquid phase or the suspensions have been coated on substrates and dried before reduction. Reducing solutions containing aminoiminomethanesulfinic acid are effective with particles of lead halides, lead phosphate, lead sulfate, and lead tartrate. Suspensions of smaller discrete lead particles have also been produced by direct reduction of solutions of soluble lead salts containing suitable polymers, chelating, and stabilizing agents. Dispersions with mean particle dimensions between 3 nm and 5 ..mu..m, and a narrow size-frequency distribution, have been produced. The superconductivity of the particles has been characterized by measurements of the magnetization as a function of temperature and magnetic field. The larger particles have a transition temperature of 7.2 K, the same as bulk lead; however, for particles of characteristic dimensions less than 20 nm, the transition temperature is lower by approx.0.1 K.

  13. Advanced Manufacturing Techniques Demonstrated for Fabricating Developmental Hardware

    NASA Technical Reports Server (NTRS)

    Redding, Chip

    2004-01-01

    NASA Glenn Research Center's Engineering Development Division has been working in support of innovative gas turbine engine systems under development by Glenn's Combustion Branch. These one-of-a-kind components require operation under extreme conditions. High-temperature ceramics were chosen for fabrication was because of the hostile operating environment. During the designing process, it became apparent that traditional machining techniques would not be adequate to produce the small, intricate features for the conceptual design, which was to be produced by stacking over a dozen thin layers with many small features that would then be aligned and bonded together into a one-piece unit. Instead of using traditional machining, we produced computer models in Pro/ENGINEER (Parametric Technology Corporation (PTC), Needham, MA) to the specifications of the research engineer. The computer models were exported in stereolithography standard (STL) format and used to produce full-size rapid prototype polymer models. These semi-opaque plastic models were used for visualization and design verification. The computer models also were exported in International Graphics Exchange Specification (IGES) format and sent to Glenn's Thermal/Fluids Design & Analysis Branch and Applied Structural Mechanics Branch for profiling heat transfer and mechanical strength analysis.

  14. Advanced fabrication techniques for hydrogen-cooled engine structures

    NASA Technical Reports Server (NTRS)

    Buchmann, O. A.; Arefian, V. V.; Warren, H. A.; Vuigner, A. A.; Pohlman, M. J.

    1985-01-01

    Described is a program for development of coolant passage geometries, material systems, and joining processes that will produce long-life hydrogen-cooled structures for scramjet applications. Tests were performed to establish basic material properties, and samples constructed and evaluated to substantiate fabrication processes and inspection techniques. Results of the study show that the basic goal of increasing the life of hydrogen-cooled structures two orders of magnitude relative to that of the Hypersonic Research Engine can be reached with available means. Estimated life is 19000 cycles for the channels and 16000 cycles for pin-fin coolant passage configurations using Nickel 201. Additional research is required to establish the fatigue characteristics of dissimilar-metal coolant passages (Nickel 201/Inconel 718) and to investigate the embrittling effects of the hydrogen coolant.

  15. Fabrication techniques for reverse electrode coaxial germanium nuclear radiation detectors

    SciTech Connect

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

    1980-11-01

    Germanium detectors with reverse polarity coaxial electrodes have been shown to exhibit improved resistance to radiation damage as compared with conventional electrode devices. However, the production of reverse electrode devices involves the development of new handling and fabrication techniques which has limited their wider application. We have developed novel techniques which lead to a device which is simple to fabricate, environmentally passivated and surface state adjusted.

  16. Low cost techniques for fabricating lobed bearings

    NASA Technical Reports Server (NTRS)

    Schuller, F. T.

    1968-01-01

    New low cost technique utilizes shims to create the lobes in bearing. Conventional methods of manufacture require accurate off-center grinding of the inside diameter of a bearing in a housing at various arc lengths depending on the number of lobes required.

  17. Fabrication and characterization of oxide fibrous monoliths produced by coextrusion.

    SciTech Connect

    Polzin, B. J.

    1999-05-19

    Unidirectional fibrous monoliths (FMs) based on dense, strong ZrSiO{sub 4} cells that were surrounded by a porous, weaker ZrSiO{sub 4} cell-boundary phase were fabricated. A duplex filament was coextruded, sectioned, bundled, and the resulting bundle was extruded to form a new filament. This filament was cut and packed into plate and bar dies to produce FM test specimens. Four-point flexural tests were conducted on the cell material, cell-boundary material, and FMs. After testing, fracture surfaces and cross sections were examined by scanning electron microscopy. The FMs exhibited graceful failure in flexural testing, and the fracture surfaces exhibited clear evidence of crack deflection and delamination.

  18. Fabrication

    NASA Technical Reports Server (NTRS)

    Angel, Roger; Helms, Richard; Bilbro, Jim; Brown, Norman; Eng, Sverre; Hinman, Steve; Hull-Allen, Greg; Jacobs, Stephen; Keim, Robert; Ulmer, Melville

    1992-01-01

    What aspects of optical fabrication technology need to be developed so as to facilitate existing planned missions, or enable new ones? Throughout the submillimeter to UV wavelengths, the common goal is to push technology to the limits to make the largest possible apertures that are diffraction limited. At any one wavelength, the accuracy of the surface must be better than lambda/30 (rms error). The wavelength range is huge, covering four orders of magnitude from 1 mm to 100 nm. At the longer wavelengths, diffraction limited surfaces can be shaped with relatively crude techniques. The challenge in their fabrication is to make as large as possible a reflector, given the weight and volume constraints of the launch vehicle. The limited cargo diameter of the shuttle has led in the past to emphasis on deployable or erectable concepts such as the Large Deployable Reflector (LDR), which was studied by NASA for a submillimeter astrophysics mission. Replication techniques that can be used to produce light, low-cost reflecting panels are of great interest for this class of mission. At shorter wavelengths, in the optical and ultraviolet, optical fabrication will tax to the limit the most refined polishing methods. Methods of mechanical and thermal stabilization of the substrate will be severely stressed. In the thermal infrared, the need for large aperture is tempered by the even stronger need to control the telescope's thermal emission by cooled or cryogenic operation. Thus, the SIRTF mirror at 1 meter is not large and does not require unusually high accuracy, but the fabrication process must produce a mirror that is the right shape at a temperature of 4 K. Future large cooled mirrors will present more severe problems, especially if they must also be accurate enough to work at optical wavelengths. At the very shortest wavelengths accessible to reflecting optics, in the x-ray domain, the very low count fluxes of high energy photons place a premium on the collecting area. It is

  19. A Comparison of Fabrication Techniques for Hollow Retroreflectors

    NASA Technical Reports Server (NTRS)

    Preston, Alix; Merkowitz, Stephen

    2014-01-01

    Despite the wide usage of hollow retroreflectors, there is limited literature involving their fabrication techniques and only two documented construction methods could be found. One consists of an adjustable fixture that allows for the independent alignment of each mirror, while the other consists of a modified solid retroreflector that is used as a mandrel. Although both methods were shown to produce hollow retroreflectors with arcsecond dihedral angle errors, a comparison and analysis of each method could not be found which makes it difficult to ascertain which method would be better suited to use for precision-aligned retroreflectors. Although epoxy bonding is generally the preferred method to adhere the three mirrors, a relatively new method known as hydroxide-catalysis bonding (HCB) presents several potential advantages over epoxy bonding. HCB has been used to bond several optical components for space-based missions, but has never been applied for construction of hollow retroreflectors. In this paper we examine the benefits and limitations of each bonding fixture as well as present results and analysis of hollow retroreflectors made using both epoxy and HCB techniques.

  20. Development of a Fluid Structures Interaction Test Technique for Fabrics

    NASA Technical Reports Server (NTRS)

    Zilliac, Gregory G.; Heineck, James T.; Schairer, Edward T.; Mosher, Robert N.; Garbeff, Theodore Joseph

    2012-01-01

    Application of fluid structures interaction (FSI) computational techniques to configurations of interest to the entry, descent and landing (EDL) community is limited by two factors - limited characterization of the material properties for fabrics of interest and insufficient experimental data to validate the FSI codes. Recently ILC Dover Inc. performed standard tests to characterize the static stress-strain response of four candidate fabrics for use in EDL applications. The objective of the tests described here is to address the need for a FSI dataset for CFD validation purposes. To reach this objective, the structural response of fabrics was measured in a very simple aerodynamic environment with well controlled boundary conditions. Two test series were undertaken. The first series covered a range of tunnel conditions and the second focused on conditions that resulted in fabric panel buckling.

  1. Rapid Fabrication Techniques for Liquid Rocket Channel Wall Nozzles

    NASA Technical Reports Server (NTRS)

    Gradl, Paul R.

    2016-01-01

    The functions of a regeneratively-cooled nozzle are to (1) expand combustion gases to increase exhaust gas velocity while, (2) maintaining adequate wall temperatures to prevent structural failure, and (3) transfer heat from the hot gases to the coolant fluid to promote injector performance and stability. Regeneratively-cooled nozzles are grouped into two categories: tube-wall nozzles and channel wall nozzles. A channel wall nozzle is designed with an internal liner containing a series of integral coolant channels that are closed out with an external jacket. Manifolds are attached at each end of the nozzle to distribute coolant to and away from the channels. A variety of manufacturing techniques have been explored for channel wall nozzles, including state of the art laser-welded closeouts and pressure-assisted braze closeouts. This paper discusses techniques that NASA MSFC is evaluating for rapid fabrication of channel wall nozzles that address liner fabrication, slotting techniques and liner closeout techniques. Techniques being evaluated for liner fabrication include large-scale additive manufacturing of freeform-deposition structures to create the liner blanks. Abrasive water jet milling is being evaluated for cutting the complex coolant channel geometries. Techniques being considered for rapid closeout of the slotted liners include freeform deposition, explosive bonding and Cold Spray. Each of these techniques, development work and results are discussed in further detail in this paper.

  2. Precision technique for side-polished fiber fabrication

    NASA Astrophysics Data System (ADS)

    Mishakov, Gennadi V.; Sokolov, Victor I.

    2002-04-01

    The precision technique for side polishing of single-mode quartz fibers is developed. The technique comprises cutting curved groove in silica block, gluing a section of bare fiber into the groove, and subsequent grinding and polishing of the silica block/fiber assembly. We succeeded in fabricating up to six side-polished fibers in one block with effective interaction length 2-4 mm. The accuracy of polishing depth was achieved at 1 micrometers using in-situ monitoring of transmission of 1.3 micrometers laser light through the fiber. The developed technique combines high accuracy, reproducibility and low cost in commercial production. Side- polished single-mode fibers fabricated with this technique can find application as elements of Bragg grating transmission filters, narrowband reflectors, optical add/drop multiplexers, couplers, polarizers, sensors, etc.

  3. 94 GHz slotted waveguide array fabricated by photolithographic techniques

    NASA Astrophysics Data System (ADS)

    Rao, B. R.

    1984-02-01

    94 GHz nonresonant shunt and series slot waveguide arrays have been fabricated by using high-resolution photolithographic and chemical etching techniques. The antenna pattern, efficiency and input reflection coefficient for the two types of arrays have been measured and are in good agreement with design predictions.

  4. New techniques for producing thin boron films

    SciTech Connect

    Thomas, G.E.

    1988-01-01

    A review will be presented of methods for producing thin boron films using an electron gun. Previous papers have had the problem of spattering of the boron source during the evaporation. Methods for reducing this problem will also be presented. 12 refs., 4 figs.

  5. Biomedical microfluidic devices by using low-cost fabrication techniques: A review.

    PubMed

    Faustino, Vera; Catarino, Susana O; Lima, Rui; Minas, Graça

    2016-07-26

    One of the most popular methods to fabricate biomedical microfluidic devices is by using a soft-lithography technique. However, the fabrication of the moulds to produce microfluidic devices, such as SU-8 moulds, usually requires a cleanroom environment that can be quite costly. Therefore, many efforts have been made to develop low-cost alternatives for the fabrication of microstructures, avoiding the use of cleanroom facilities. Recently, low-cost techniques without cleanroom facilities that feature aspect ratios more than 20, for fabricating those SU-8 moulds have been gaining popularity among biomedical research community. In those techniques, Ultraviolet (UV) exposure equipment, commonly used in the Printed Circuit Board (PCB) industry, replaces the more expensive and less available Mask Aligner that has been used in the last 15 years for SU-8 patterning. Alternatively, non-lithographic low-cost techniques, due to their ability for large-scale production, have increased the interest of the industrial and research community to develop simple, rapid and low-cost microfluidic structures. These alternative techniques include Print and Peel methods (PAP), laserjet, solid ink, cutting plotters or micromilling, that use equipment available in almost all laboratories and offices. An example is the xurography technique that uses a cutting plotter machine and adhesive vinyl films to generate the master moulds to fabricate microfluidic channels. In this review, we present a selection of the most recent lithographic and non-lithographic low-cost techniques to fabricate microfluidic structures, focused on the features and limitations of each technique. Only microfabrication methods that do not require the use of cleanrooms are considered. Additionally, potential applications of these microfluidic devices in biomedical engineering are presented with some illustrative examples. PMID:26671220

  6. Suspended metal mask techniques in Josephson junction fabrication

    SciTech Connect

    Ono, R.H.; Sauvageau, J.E.; Jain, A.K.; Schwartz, D.B.; Springer, K.T.; Lukens, J.E.

    1985-01-01

    We report here two processes for in-situ, self-aligned fabrication of niobium based Josephson tunnel junctions and SNS microbridges in which multiple evaporations at varying angles are made through a suspended metal stencil fabricated by electron beam lithography (EBL). Both techniques have proved superior to earlier all-polymer suspended masks, particularly with e-gun evaporated refractory metals such as niobium. The first process uses a trilevel resist and ion milling to pattern a gold stencil suspended on PMMA. In the second process, an aluminum stencil suspended on polyimide (PI) is patterned by lift-off with an EBL mask written in a PMMA layer on top of the PI. The PI is then undercut using an oxygen plasma etch through the aluminum mask. Reproducible ( +- 20 nm) submicrometer dimensions and good junction characteristics have been achieved using these techniques without the need for difficult-to-control surface cleaning procedures.

  7. Recent Developments in Microsystems Fabricated by the Liga-Technique

    NASA Technical Reports Server (NTRS)

    Schulz, J.; Bade, K.; El-Kholi, A.; Hein, H.; Mohr, J.

    1995-01-01

    As an example of microsystems fabricated by the LIGA-technique (x-ray lithography, electroplating and molding), three systems are described and characterized: a triaxial acceleration sensor system, a micro-optical switch, and a microsystem for the analysis of pollutants. The fabrication technologies are reviewed with respect to the key components of the three systems: an acceleration sensor, and electrostatic actuator, and a spectrometer made by the LIGA-technique. Aa micro-pump and micro-valve made by using micromachined tools for molding and optical fiber imaging are made possible by combining LIGA and anisotropic etching of silicon in a batch process. These examples show that the combination of technologies and components is the key to complex microsystems. The design of such microsystems will be facilitated is standardized interfaces are available.

  8. Techniques of Fabrication of Provisional Restoration: An Overview

    PubMed Central

    Regish, K. M.; Sharma, Deeksha; Prithviraj, D. R.

    2011-01-01

    A properly fabricated provisional restoration is important in achieving a successful indirect restoration. The importance of provisional restorations as an integral part of fixed prosthodontic treatment is evident from the abundance of the literature pertaining to their importance regarding margin fidelity, function, occlusion, and esthetics. There are a variety of techniques available to suit the individual needs of the clinician and of the clinical situation, from a single unit to a complete-arch provisional fixed prostheses. PMID:22013441

  9. Mirror substrate fabrication techniques of low expansion glasses.

    NASA Astrophysics Data System (ADS)

    Spangenberg-Jolley, J.; Hobbs, T.

    1989-04-01

    Low expansion glasses offer many advantages as mirror blank materials due to their thermal and mechanical properties as well as the flexibility they offer in design and fabrication. Fused Silica, Corning Code 7940 and ULETM titanium silicate, Code 7971, produced by the flame hydrolysis process, are high purity and homogeneous glasses. The ability to fusion seal each of the glasses offers mirror manufacturing design freedom of shape, size and weight.

  10. Advanced Fibre Bragg Grating and Microfibre Bragg Grating Fabrication Techniques

    NASA Astrophysics Data System (ADS)

    Chung, Kit Man

    Fibre Bragg gratings (FBGs) have become a very important technology for communication systems and fibre optic sensing. Typically, FBGs are less than 10-mm long and are fabricated using fused silica uniform phase masks which become more expensive for longer length or non-uniform pitch. Generally, interference UV laser beams are employed to make long or complex FBGs, and this technique introduces critical precision and control issues. In this work, we demonstrate an advanced FBG fabrication system that enables the writing of long and complex gratings in optical fibres with virtually any apodisation profile, local phase and Bragg wavelength using a novel optical design in which the incident angles of two UV beams onto an optical fibre can be adjusted simultaneously by moving just one optical component, instead of two optics employed in earlier configurations, to vary the grating pitch. The key advantage of the grating fabrication system is that complex gratings can be fabricated by controlling the linear movements of two translation stages. In addition to the study of advanced grating fabrication technique, we also focus on the inscription of FBGs written in optical fibres with a cladding diameter of several ten's of microns. Fabrication of microfibres was investigated using a sophisticated tapering method. We also proposed a simple but practical technique to filter out the higher order modes reflected from the FBG written in microfibres via a linear taper region while the fundamental mode re-couples to the core. By using this technique, reflection from the microfibre Bragg grating (MFBG) can be effectively single mode, simplifying the demultiplexing and demodulation processes. MFBG exhibits high sensitivity to contact force and an MFBG-based force sensor was also constructed and tested to investigate their suitability for use as an invasive surgery device. Performance of the contact force sensor packaged in a conforming elastomer material compares favourably to one

  11. Super-smooth surface fabrication technique and experimental research.

    PubMed

    Zhang, Linghua; Wang, Junlin; Zhang, Jian

    2012-09-20

    Wheel polishing, a new optical fabrication technique, is proposed for super-smooth surface fabrication of optical components in high-precision optical instruments. The machining mechanism and the removal function contours are investigated in detail. The elastohydrodynamic lubrication theory is adopted to analyze the deformation of the wheel head, the pressure distribution, and the fluid film thickness distribution in the narrow machining zone. The pressure and the shear stress distributions at the interface between the slurry and the sample are numerically simulated. Practical polishing experiments are arranged to analyze the relationship between the wheel-sample distance and the machining rate. It is demonstrated in this paper that the wheel-sample distance will directly influence the removal function contours. Moreover, ripples on the wheel surface will eventually induce the transverse prints on the removal function contours. The surface roughness of fused silicon is reduced to less than 0.5 nm (rms) from initial 1.267 nm (rms). The wheel polishing technique is feasible for super-smooth surface fabrication. PMID:23033032

  12. New Advanced Fabrication Technique for Millimeter-Wave Planar Components based on Fluororesin Substrates using Graft Polymerization

    NASA Astrophysics Data System (ADS)

    Ito, Naoki; Mase, Atsushi; Kogi, Yuichiro; Seko, Noriaki; Tamada, Masao; Sakata, Eiji

    2008-06-01

    As the importance of advanced millimeter-wave diagnostics increases, a reliable and accurate fabrication technique for high-performance devices and relevant components is essential. We describe a new improved fabrication technique for millimeter-wave planar components, such as antennas using low-loss fluororesin substrates. A fragile adhesion between the copper foil and fluororesin substrate and the accuracy of the device pattern using conventional fabrication techniques have been prime suspects in the failure of the devices. In order to solve these problems, surface treatment of fluororesin films and a fabrication method using electro-fine-forming (EF2) are proposed. The peel adhesion strength between the metal and fluororesin films and the value of the dielectric constant of the fluororesin films before and after grafting are reported. A prototype antenna using conventional fluororesin substrates and grafted-poly(tetrafluoroethylene) (PTFE) films produced using the EF2 fabrication technique are also introduced.

  13. FY-87 packing fabrication techniques (commercial waste form) results

    SciTech Connect

    Werry, E.V.; Gates, T.E.; Cabbage, K.S.; Eklund, J.D.

    1988-04-01

    This report covers the investigation of fabrication techniques associated with the development of suitable materials and methods to provide a prefabricated packing for waste packages for the Basalt Waste Isolation Project (BWIP). The principal functions of the packing are to minimize container corrosion during the 300 to 1000 years following repository closure and provide long-term control of the release of radionuclides from the waste package. The investigative work, discussed in this report, was specifically conceived to develop the design criteria for production of full-scale prototypical packing rings. The investigative work included the preparation of procedures, the preparation of fabrication materials, physical properties, and the determination of the engineering properties. The principal activities were the preparation of the materials and the determination of the physical properties. 21 refs., 20 figs., 14 tabs.

  14. Innovative sputtering techniques for CIS and CdTe submodule fabrication

    SciTech Connect

    Armstrong, J.M.; Misra, M.S.; Lanning, B. . Astronautics Group)

    1993-03-01

    This report describes work done during Phase 1 of the subject subcontract. The subcontract was designed to study innovative deposition techniques, such as the rotating cylindrical magnetron sputtering system and electrodeposition for large-area, low-cost copper indium diselenide (CIS) and cadmium telluride (CdTe) devices. A key issue for photovoltaics (PV) in terrestrial and future space applications is producibility, particularly for applications using a large quantity of PV. Among the concerns for fabrication of polycrystalline thin-film PV, such as CIS and CdTe, are production volume, cost, and minimization of waste. Both rotating cylindrical magnetron (C-Mag[trademark]) sputtering and electrodeposition have tremendous potential for the fabrication of polycrystalline thin-film PV due to scaleability, efficient utilization of source materials, and inherently higher deposition rates. In the case of sputtering, the unique geometry of the C-Mae facilitates innovative cosputtering and reactive sputtering that could lead to greater throughput reduced health and safety risks, and, ultimately, lower fabrication cost. Electrodeposited films appear to be adherent and comparable with low-cost fabrication techniques. Phase I involved the initial film and device fabrication using the two techniques mentioned herein. Devices were tested by both internal facilities, as well as NREL and ISET.

  15. Method for producing fabrication material for constructing micrometer-scaled machines, fabrication material for micrometer-scaled machines

    SciTech Connect

    Stevens, F.J.

    1995-12-31

    A method for producing fabrication material for use in the construction of nanometer-scaled machines is provided whereby similar protein molecules are isolated and manipulated at predetermined residue positions so as to facilitate noncovalent interaction, but without compromising the folding configuration or native structure of the original protein biomodules. A fabrication material is also provided consisting of biomodules systematically constructed and arranged at specific solution parameters.

  16. In-office technique to fabricate triple tray.

    PubMed

    Nanda, Aditi; Kaur, Harsimran; Koli, Dheeraj; Manak, Karan; Verma, Mahesh

    2015-01-01

    Dual arch impressions have been in use for many years. Five in-office techniques for fabrication of the tray have been suggested, in case the manufactured (stock) tray is not available to the clinician. The design consists of two parts of the tray (the plastic frame and lattice). Five types of materials for the lattice have been described. The indications, advantages, and disadvantages of the techniques together with an appraisal of the five different lattice materials have been described. Overall the techniques are simple and require materials that are easily available. It does not take much time and can be used to attain efficient results in case the stock tray is not available in the operatory. PMID:26888248

  17. A modified technique for fabricating a mirror image wax pattern for an auricular prosthesis.

    PubMed

    Gajdhar, Shaiq; Gajdhar, Sajda Khan; Salakalakonda, Srikanth Reddy; Vasthare, Abubakkar

    2015-01-01

    This article describes a technique for fabricating a wax pattern for an auricular prosthesis by tracing the shape of a sliced cast of the contralateral ear at an interval of 1-mm and transferring the shape of each 1-mm slice to a similar dimension modeling wax sheet. In this way, slices of modeling wax are obtained, which can be reversed and placed over the previous slice to produce a mirror image wax pattern of the contralateral ear. PMID:25277032

  18. Method of producing catalytic materials for fabricating nanostructures

    DOEpatents

    Seals, Roland D; Menchhofer, Paul A; Howe, Jane Y; Wang, Wei

    2013-02-19

    Methods of fabricating nano-catalysts are described. In some embodiments the nano-catalyst is formed from a powder-based substrate material and is some embodiments the nano-catalyst is formed from a solid-based substrate material. In some embodiments the substrate material may include metal, ceramic, or silicon or another metalloid. The nano-catalysts typically have metal nanoparticles disposed adjacent the surface of the substrate material. The methods typically include functionalizing the surface of the substrate material with a chelating agent, such as a chemical having dissociated carboxyl functional groups (--COO), that provides an enhanced affinity for metal ions. The functionalized substrate surface may then be exposed to a chemical solution that contains metal ions. The metal ions are then bound to the substrate material and may then be reduced, such as by a stream of gas that includes hydrogen, to form metal nanoparticles adjacent the surface of the substrate.

  19. Novel immobilization techniques in the fabrication of efficient electrochemical biosensors

    NASA Astrophysics Data System (ADS)

    Alva, Shridhara; Marx, Kenneth A.; Samuelson, Lynne A.; Kumar, Jayant; Tripathy, Sukant K.; Kaplan, David L.

    1996-02-01

    The development of enzyme electrodes plays a major role in the performance of an electrochemical biosensor. In this paper, we describe two generic methods for efficient immobilization of enzymes or biomolecules at the electrode surface. These methods are based on physical entrapment of the enzymes during biochemical polymerization of phenols and electrochemical copolymerization of aromatic diamines with enzymes that are covalently coupled to the monomer. Both of these techniques have proven to be chemically mild and provide efficient polymer matrices for the fabrication of enzyme electrodes. Enzymes including horseradish peroxidase, alkaline phosphatase and glucose oxidase have been immobilized in these polymeric matrices and used for electrochemical as well as colorimetric detection of various substrates. Response times of the order of 5 - 10 seconds and sensitivities of the order of mM have been achieved with these electrodes. The use of these immobilization techniques towards the development of microelectrode arrays for multianalyte sensors is also discussed.

  20. Advanced Materials and Fabrication Techniques for the Orion Attitude Control Motor

    NASA Technical Reports Server (NTRS)

    Gorti, Sridhar; Holmes, Richard; O'Dell, John; McKechnie, Timothy; Shchetkovskiy, Anatoliy

    2013-01-01

    Rhenium, with its high melting temperature, excellent elevated temperature properties, and lack of a ductile-to-brittle transition temperature (DBTT), is ideally suited for the hot gas components of the ACM (Attitude Control Motor), and other high-temperature applications. However, the high cost of rhenium makes fabricating these components using conventional fabrication techniques prohibitive. Therefore, near-net-shape forming techniques were investigated for producing cost-effective rhenium and rhenium alloy components for the ACM and other propulsion applications. During this investigation, electrochemical forming (EL-Form ) techniques were evaluated for producing the hot gas components. The investigation focused on demonstrating that EL-Form processing techniques could be used to produce the ACM flow distributor. Once the EL-Form processing techniques were established, a representative rhenium flow distributor was fabricated, and samples were harvested for material properties testing at both room and elevated temperatures. As a lower cost and lighter weight alternative to an all-rhenium component, rhenium- coated graphite and carbon-carbon were also evaluated. The rhenium-coated components were thermal-cycle tested to verify that they could withstand the expected thermal loads during service. High-temperature electroforming is based on electrochemical deposition of compact layers of metals onto a mandrel of the desired shape. Mandrels used for electro-deposition of near-net shaped parts are generally fabricated from high-density graphite. The graphite mandrel is easily machined and does not react with the molten electrolyte. For near-net shape components, the inner surface of the electroformed part replicates the polished graphite mandrel. During processing, the mandrel itself becomes the cathode, and scrap or refined refractory metal is the anode. Refractory metal atoms from the anode material are ionized in the molten electrolytic solution, and are deposited

  1. Micro cycloid-gear system fabricated by multiexposure LIGA technique

    NASA Astrophysics Data System (ADS)

    Hirata, Toru; Chung, Song-Jo; Hein, Herbert; Akashi, Tomoyuki; Mohr, Juergen

    1999-09-01

    In this paper, a prototype of 2 mm-diameter micro-cycloid gear system fabricated by the multi-exposure LIGA technique is presented. The entire gear system consists of a casing and three vertically stacked disks and gears. Each part is composed of three different levels. The first level, 40 micrometers high, was fabricated by UV-lithography, and the second as well as the third level, 195 micrometers and 250 micrometers high respectively, were processed by aligned deep X-ray lithography (DXL). The alignment error between two DXL- processed layers was measured, and the results have turned out to be within +/- 5 micrometers range. As a result of the height control process by the mechanical surface machining, the deviation of structural height has been maintained within +/- 3 micrometers range for the UV-lithography-processed structures, and +/- 10 micrometers for the DXL-processed structures. Further the tests of gear assembly were implemented with 125 micrometers -diameter glass fiber, by using a die-bonding machine with vacuum gripper under stereo- microscope. Finally the dynamic tests of the gear system were successfully conducted with the mechanical torque input by an electrical motor. A proper rotational speed reduction was observed in the operational input range of 3 to 1500 rpm with the designed gear ratio of 18.

  2. Chromatic changes to artificial irises produced using different techniques

    NASA Astrophysics Data System (ADS)

    Bannwart, Lisiane Cristina; Goiato, Marcelo Coelho; dos Santos, Daniela Micheline; Moreno, Amália; Pesqueira, Aldiéris Alves; Haddad, Marcela Filié; Andreotti, Agda Marobo; de Medeiros, Rodrigo Antonio

    2013-05-01

    Ocular prostheses are important determinants of their users' aesthetic recovery and self-esteem. Because of use, ocular prostheses longevity is strongly affected by instability of the iris color due to polymerization. The goal of this study is to examine how the color of the artificial iris button is affected by different techniques of artificial wear and by the application of varnish following polymerization of the colorless acrylic resin that covers the colored paint. We produce 60 samples (n=10) according to the wear technique applied: conventional technique without varnish (PE); conventional technique with varnish (PEV); technique involving a prefabricated cap without varnish (CA); technique involving a prefabricated cap with varnish (CAV); technique involving inverted painting without varnish (PI); and technique involving inverted painting with varnish (PIV). Color readings using a spectrophotometer are taken before and after polymerization. We submitted the data obtained to analyses of variance and Tukey's test (P<0.05). The color test shows significant changes after polymerization in all groups. The PE and PI techniques have clinically acceptable values of ΔE, independent of whether we apply varnish to protect the paint. The PI technique produces the least color change, whereas the PE and CA techniques significantly improve color stability.

  3. Computational Electromagnetic Modeling of Optical Responses in Plasmonically Enhanced Nanoscale Devices Fabricated with Nanomasking Technique

    NASA Astrophysics Data System (ADS)

    Novak, Eric; Debu, Desalegn; Saylor, Cameron; Herzog, Joseph

    2015-03-01

    This work computationally explores plasmonic nanoscale devices fabricated with a recently developed nanomasking technique that is based on the self-aligned process. Computational electromagnetic modeling has determined enhancement factors and the plasmonic and optical properties of these structures. The nanomasking technique is a new process that is employed to overcome the resolution limits of traditional electron beam lithography and can also be used to increase resolution in photolithography fabrication as well. This technique can consistently produce accurate features with nanostructures and gaps smaller than 10 nm. These smaller dimensions can allow for increased and more localized plasmonically enhanced electric fields. These unique metal devices encompass tunable, enhanced plasmonic and optical properties that can be useful in a wide range of applications. Finite element methods are used to approximate the electromagnetic responses, giving the ability to alter the designs and dimensions in order to optimize the enhancement. Ultimately, we will fabricate devices and characterize the plasmonic properties with optical techniques, including dark-field spectroscopy, to confirm the properties with the goal of generating more efficient devices.

  4. Fabrication, characterization, and biocompatibility of single-walled carbon nanotube-reinforced alginate composite scaffolds manufactured using freeform fabrication technique.

    PubMed

    Yildirim, Eda D; Yin, Xi; Nair, Kalyani; Sun, Wei

    2008-11-01

    Composite polymeric scaffolds from alginate and single-walled carbon nanotube (SWCNT) were produced using a freeform fabrication technique. The scaffolds were characterized for their structural, mechanical, and biological properties by scanning electron microscopy, Raman spectroscopy, tensile testing, and cell-scaffold interaction study. Three-dimensional hybrid alginate/SWCNT tissue scaffolds were fabricated in a multinozzle biopolymer deposition system, which makes possible to disperse and align SWCNTs in the alginate matrix. The structure of the resultant scaffolds was significantly altered due to SWCNT reinforcement, which was confirmed by Raman spectroscopy. Microtensile testing presented a reinforcement effect of SWCNT to the mechanical strength of the alginate struts. Ogden constitutive modeling was utilized to predict the stress-strain relationship of the alginate scaffold, which compared well with the experimental data. Cellular study by rat heart endothelial cell showed that the SWCNT incorporated in the alginate structure improved cell adhesion and proliferation. Our study suggests that hybrid alginate/SWCNT scaffolds are a promising biomaterial for tissue engineering applications. PMID:18506813

  5. Fabrication of a microreactor by proton beam writing technique

    NASA Astrophysics Data System (ADS)

    Huszank, R.; Szilasi, S. Z.; Vad, K.; Rajta, I.

    2009-06-01

    Microreactors are innovative and promising tools in technology nowadays because of their advantages compared to the conventional-scale reactors. These advantages include vast improvements in surface to volume ratio, energy efficiency, reaction speed and yield and increased control of reaction conditions, to name a few examples. The high resolution capability of the micromachining technique utilizing accelerated ion beams in the fabrication technology of microreactors has not yet been taken advantage of. In this work we present the design of a prototype micro-electrochemical cell of 1.5 μL volume (2.5 × 2.5 × 0.240 mm) created with a 3 MeV proton microbeam. The cell can be separated into two half-cells with a suitable membrane applicable to galvanic or fuel cells as well. We deposited gold electrodes on both of the half-cells. The operability of the device was demonstrated by electric current flow between the two electrodes in this micro-electrochemical cell containing a simple electrolyte solution. We used a polycapillary film to separate the two half-cells, hindering the mixing of the anolyte and catholyte solutions. As a result of the minimal mixing caused by the polycapillary film, this cell design can be suitable for electro-synthesis. Due to the high resolution of proton beam writing, it is planned to reduce the dimensions of this kind of microreactor.

  6. Thermocapillary Technique for Shaping and Fabricating Optical Ribbon Waveguides

    NASA Astrophysics Data System (ADS)

    Fiedler, Kevin; Troian, Sandra

    The demand for ever increasing bandwidth and higher speed communication has ushered the next generation optoelectronic integrated circuits which directly incorporate polymer optical waveguide devices. Polymer melts are very versatile materials which have been successfully cast into planar single- and multimode waveguides using techniques such as embossing, photolithography and direct laser writing. In this talk, we describe a novel thermocapillary patterning method for fabricating waveguides in which the free surface of an ultrathin molten polymer film is exposed to a spatially inhomogeneous temperature field via thermal conduction from a nearby cooled mask pattern held in close proximity. The ensuring surface temperature distribution is purposely designed to pool liquid selectively into ribbon shapes suitable for optical waveguiding, but with rounded and not rectangular cross sectional areas due to capillary forces. The solidified waveguide patterns which result from this non-contact one step procedure exhibit ultrasmooth interfaces suitable for demanding optoelectronic applications. To complement these studies, we have also conducted finite element simulations for quantifying the influence of non-rectangular cross-sectional shapes on mode propagation and losses. Kf gratefully acknowledges support from a NASA Space Technology Research Fellowship.

  7. Fabricating protein immunoassay arrays on nitrocellulose using dip-pen lithography techniques.

    PubMed

    Irvine, Eleanore Jane; Hernandez-Santana, Aaron; Faulds, Karen; Graham, Duncan

    2011-07-21

    Advancements in lithography methods for printing biomolecules on surfaces are proving to be potentially beneficial for disease screening and biological research. Dip-pen nanolithography (DPN) is a versatile micro and nanofabrication technique that has the ability to produce functional biomolecule arrays. The greatest advantage, with respect to the printing mechanism, is that DPN adheres to the sensitive mild conditions required for biomolecules such as proteins. We have developed an optimised, high-throughput printing technique for fabricating protein arrays using DPN. This study highlights the fabrication of a prostate specific antigen (PSA) immunoassay detectable by fluorescence. Spot sizes are typically no larger than 8 μm in diameter and limits of detection for PSA are comparable with a commercially available ELISA kit. Furthermore, atomic force microscopy (AFM) analysis of the array surface gives great insight into how the nitrocellulose substrate functions to retain protein integrity. This is the first report of protein arrays being printed on nitrocellulose using the DPN technique and the smallest feature size yet to be achieved on this type of surface. This method offers a significant advance in the ability to produce dense protein arrays on nitrocellulose which are suitable for disease screening using standard fluorescence detection. PMID:21647488

  8. Effect of fabrication technique on direct methanol fuel cells designed to operate at low airflow

    NASA Technical Reports Server (NTRS)

    Valdez, T. I.; Narayanan, S. R.

    2002-01-01

    This study investigates the effects of catalyst ink constituents and MEA fabrication techniques on improving cell performance. Particular attention was focused on increasing the overall cell efficiency.

  9. Improved ceramic slip casting technique. [application to aircraft model fabrication

    NASA Technical Reports Server (NTRS)

    Buck, Gregory M. (Inventor); Vasquez, Peter (Inventor)

    1993-01-01

    A primary concern in modern fluid dynamics research is the experimental verification of computational aerothermodynamic codes. This research requires high precision and detail in the test model employed. Ceramic materials are used for these models because of their low heat conductivity and their survivability at high temperatures. To fabricate such models, slip casting techniques were developed to provide net-form, precision casting capability for high-purity ceramic materials in aqueous solutions. In previous slip casting techniques, block, or flask molds made of plaster-of-paris were used to draw liquid from the slip material. Upon setting, parts were removed from the flask mold and cured in a kiln at high temperatures. Casting detail was usually limited with this technique -- detailed parts were frequently damaged upon separation from the flask mold, as the molded parts are extremely delicate in the uncured state, and the flask mold is inflexible. Ceramic surfaces were also marred by 'parting lines' caused by mold separation. This adversely affected the aerodynamic surface quality of the model as well. (Parting lines are invariably necessary on or near the leading edges of wings, nosetips, and fins for mold separation. These areas are also critical for flow boundary layer control.) Parting agents used in the casting process also affected surface quality. These agents eventually soaked into the mold, the model, or flaked off when releasing the case model. Different materials were tried, such as oils, paraffin, and even an algae. The algae released best, but some of it remained on the model and imparted an uneven texture and discoloration on the model surface when cured. According to the present invention, a wax pattern for a shell mold is provided, and an aqueous mixture of a calcium sulfate-bonded investment material is applied as a coating to the wax pattern. The coated wax pattern is then dried, followed by curing to vaporize the wax pattern and leave a shell

  10. Fabrication of Polymeric Coatings with Controlled Microtopographies Using an Electrospraying Technique

    PubMed Central

    Guo, Qiongyu; Mather, Jason P.; Yang, Pine; Boden, Mark; Mather, Patrick T.

    2015-01-01

    Surface topography of medical implants provides an important biophysical cue on guiding cellular functions at the cell-implant interface. However, few techniques are available to produce polymeric coatings with controlled microtopographies onto surgical implants, especially onto implant devices of small dimension and with complex structures such as drug-eluting stents. Therefore, the main objective of this study was to develop a new strategy to fabricate polymeric coatings using an electrospraying technique based on the uniqueness of this technique in that it can be used to produce a mist of charged droplets with a precise control of their shape and dimension. We hypothesized that this technique would allow facile manipulation of coating morphology by controlling the shape and dimension of electrosprayed droplets. More specifically, we employed the electrospraying technique to coat a layer of biodegradable polyurethane with tailored microtopographies onto commercial coronary stents. The topography of such stent coatings was modulated by controlling the ratio of round to stretched droplets or the ratio of round to crumped droplets under high electric field before deposition. The shape of electrosprayed droplets was governed by the stability of these charged droplets right after ejection or during their flight in the air. Using the electrospraying technique, we achieved conformal polymeric coatings with tailored microtopographies onto conductive surgical implants. The approach offers potential for controlling the surface topography of surgical implant devices to modulate their integration with surrounding tissues. PMID:26090663

  11. Fabrication of Polymeric Coatings with Controlled Microtopographies Using an Electrospraying Technique.

    PubMed

    Guo, Qiongyu; Mather, Jason P; Yang, Pine; Boden, Mark; Mather, Patrick T

    2015-01-01

    Surface topography of medical implants provides an important biophysical cue on guiding cellular functions at the cell-implant interface. However, few techniques are available to produce polymeric coatings with controlled microtopographies onto surgical implants, especially onto implant devices of small dimension and with complex structures such as drug-eluting stents. Therefore, the main objective of this study was to develop a new strategy to fabricate polymeric coatings using an electrospraying technique based on the uniqueness of this technique in that it can be used to produce a mist of charged droplets with a precise control of their shape and dimension. We hypothesized that this technique would allow facile manipulation of coating morphology by controlling the shape and dimension of electrosprayed droplets. More specifically, we employed the electrospraying technique to coat a layer of biodegradable polyurethane with tailored microtopographies onto commercial coronary stents. The topography of such stent coatings was modulated by controlling the ratio of round to stretched droplets or the ratio of round to crumped droplets under high electric field before deposition. The shape of electrosprayed droplets was governed by the stability of these charged droplets right after ejection or during their flight in the air. Using the electrospraying technique, we achieved conformal polymeric coatings with tailored microtopographies onto conductive surgical implants. The approach offers potential for controlling the surface topography of surgical implant devices to modulate their integration with surrounding tissues. PMID:26090663

  12. Modified fabrication techniques lead to improved centrifugal blood pump performance.

    PubMed

    Pacella, J J; Goldstein, A H; Magovern, G J; Clark, R F

    1994-01-01

    The authors are developing an implantable centrifugal blood pump for short- and medium-term (1-6 months) left ventricular assist. They hypothesized that the application of result dependent modifications to this pump would lead to overall improved performance in long-term implantation studies. Essential requirements for pump operation, such as durability and resistance to clot formation, have been achieved through specialized fabrication techniques. The antithrombogenic character of the pump has been improved through coating at the cannula-housing interfaces and the baffle seal, and through changing the impeller blade material from polysulfone to pyrolytic carbon. The electronic components of the pump have been sealed for implantable use through specialized processes of dipping and potting, and the surfaces of the internal pump components have been treated to increase durability. The device has demonstrated efficacy in five chronic sheep implantation studies of 14, 10, 28, 35, and 154 day duration. Post mortem findings from the 14 day experiment showed stable fibrin entangled around the impeller shaft and blades. After pump modification, autopsy findings of the 10 day study showed no evidence of clot. Additionally, the results of the 28 day experiment showed only a small (2.0 mm) ring of fibrin at the shaft-seal interface. In the 35 and 154 day experiments, redesign of the stators have resulted in improved motor corrosion resistance. The 35 day study showed a small, 0.5 mm wide fibrin deposit at the lip seal, but no motor failure. In the 154 day experiment, the motor failed because of stator fluid corrosion, while the explanted pump was devoid of thrombus. Based on these findings, the authors believe that these pump refinements have contributed significantly to improvements in durability and resistance to clot formation. PMID:8555619

  13. Synthesis of nano silver on cellulosic denim fabric producing yellow colored garment with antibacterial properties.

    PubMed

    Maryan, Ali Sadeghian; Montazer, Majid; Harifi, Tina

    2015-01-22

    In this study, an aged-look denim fabric with antibacterial property was prepared in one single step process. For this purpose, the simultaneous antibacterial finishing and discoloration of denim fabric was carried out through reduction of indigo dye and silver nitrate by glucose in alkaline media using a conventional garment washing machine. The uniform distribution of silver nanoparticles on the fiber surface was confirmed by scanning electron microscope and energy dispersive X-ray spectroscopy. The treated fabrics were also characterized by X-ray diffraction (XRD) and Raman spectroscopy. Due to the color changes during the process, the color coordinates of the treated samples were also measured. Findings suggest the potential of the proposed method in producing old-look denim fabric with desirable yellow appearance and reasonable antibacterial activity against Staphylococcus aureus and Escherichia coli with low toxicity for human. PMID:25439933

  14. Physical and combustion properties of nonwoven fabrics produced from conventional and naturally colored cottons

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A comparative study was conducted to identify the effects of processing parameters on physical and combustion properties of needlepunched (NP) and hydroentangled (H-E) nonwoven fabrics produced from fibers of a standard Mid-South white fiber cotton and a naturally colored brown fiber cotton. The fl...

  15. The hydroentanglement system of producing nonwoven fabrics of certain specific attributes and functionalities

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although the traditional technologies and processes of producing fabric structures, via yarn spinning, weaving, knitting, lacing, tufting, or the like, continue to be the ‘major league’ players in textile manufacturing today, the modern hydroentanglement system, commonly known as “spunlacing,” has a...

  16. Structural design and fabrication techniques of composite unmanned aerial vehicles

    NASA Astrophysics Data System (ADS)

    Hunt, Daniel Stephen

    Popularity of unmanned aerial vehicles has grown substantially in recent years both in the private sector, as well as for government functions. This growth can be attributed largely to the increased performance of the technology that controls these vehicles, as well as decreasing cost and size of this technology. What is sometimes forgotten though, is that the research and advancement of the airframes themselves are equally as important as what is done with them. With current computer-aided design programs, the limits of design optimization can be pushed further than ever before, resulting in lighter and faster airframes that can achieve longer endurances, higher altitudes, and more complex missions. However, realization of a paper design is still limited by the physical restrictions of the real world and the structural constraints associated with it. The purpose of this paper is to not only step through current design and manufacturing processes of composite UAVs at Oklahoma State University, but to also focus on composite spars, utilizing and relating both calculated and empirical data. Most of the experience gained for this thesis was from the Cessna Longitude project. The Longitude is a 1/8 scale, flying demonstrator Oklahoma State University constructed for Cessna. For the project, Cessna required dynamic flight data for their design process in order to make their 2017 release date. Oklahoma State University was privileged enough to assist Cessna with the mission of supporting the validation of design of their largest business jet to date. This paper will detail the steps of the fabrication process used in construction of the Longitude, as well as several other projects, beginning with structural design, machining, molding, skin layup, and ending with final assembly. Also, attention will be paid specifically towards spar design and testing in effort to ease the design phase. This document is intended to act not only as a further development of current

  17. Technique for the efficient and reproducible fabrication of electromagnetic levitation coils

    NASA Technical Reports Server (NTRS)

    Ethridge, E. C.; Curreri, P. A.; Theiss, J.; Abbaschian, G. J.

    1984-01-01

    A technique has been developed for fabricating electromagnetic induction coils in a reproducible manner. The process utilizes a split mandrel that can be disassembled to remove the mandrel from the coil. The technique has increased coil production rates by a factor of 8 over the freehand winding method. The success rate for producing a functional levitation coil has been increased from 50 percent to 95 percent. The levitation coil designed during this work has successfully levitated and melted a variety of alloys including Cu, Ag, Ag-Ni, Cu-Fe, Fe-C, and Nb-Ge. W was also levitated but not melted at temperatures as high as 2700 C. The highest sample melt temperature achieved was 2400 C for the Nb-Ge samples.

  18. New alnico magnets fabricated from pre-alloyed gas-atomized powder through diverse consolidation techniques

    SciTech Connect

    Tang, W.; Zhou, L.; Kassen, A. G.; Palasyuk, A.; White, E. M.; Dennis, K. W.; Kramer, M. J.; McCallum, R. W.; Anderson, I. E.

    2015-05-25

    Fine Alnico 8 spherical powder produced by gas atomization was consolidated through hot pressing (HP), hot isostatic pressing (HIP), and compression molding and subsequent sintering (CMS) techniques. The effects of different fabrication techniques and processing parameters on microstructure and magnetic properties were analyzed and compared. The HP, HIP, and CMS magnets exhibited different features in microstructures and magnetic properties. Magnetically annealed at 840°C for 10 min and subsequently tempered at 650°C for 5h and 580°C for 15h, the HIP sample achieved the best coercivity (Hcj =1845 Oe) due to spinodally decomposed (SD) phases with uniform and well-faceted mosaic morphology. As a result, the CMS sample had a lower Hcj than HIP and HP samples, but a higher remanence and thus the best energy product (6.5 MGOe) due to preferential grain alignment induced by abnormal grain growth.

  19. New alnico magnets fabricated from pre-alloyed gas-atomized powder through diverse consolidation techniques

    DOE PAGESBeta

    Tang, W.; Zhou, L.; Kassen, A. G.; Palasyuk, A.; White, E. M.; Dennis, K. W.; Kramer, M. J.; McCallum, R. W.; Anderson, I. E.

    2015-05-25

    Fine Alnico 8 spherical powder produced by gas atomization was consolidated through hot pressing (HP), hot isostatic pressing (HIP), and compression molding and subsequent sintering (CMS) techniques. The effects of different fabrication techniques and processing parameters on microstructure and magnetic properties were analyzed and compared. The HP, HIP, and CMS magnets exhibited different features in microstructures and magnetic properties. Magnetically annealed at 840°C for 10 min and subsequently tempered at 650°C for 5h and 580°C for 15h, the HIP sample achieved the best coercivity (Hcj =1845 Oe) due to spinodally decomposed (SD) phases with uniform and well-faceted mosaic morphology. Asmore » a result, the CMS sample had a lower Hcj than HIP and HP samples, but a higher remanence and thus the best energy product (6.5 MGOe) due to preferential grain alignment induced by abnormal grain growth.« less

  20. Wire electric-discharge machining and other fabrication techniques

    NASA Technical Reports Server (NTRS)

    Morgan, W. H.

    1983-01-01

    Wire electric discharge machining and extrude honing were used to fabricate a two dimensional wing for cryogenic wind tunnel testing. Electric-discharge cutting is done with a moving wire electrode. The cut track is controlled by means of a punched-tape program and the cutting feed is regulated according to the progress of the work. Electric-discharge machining involves no contact with the work piece, and no mechanical force is exerted. Extrude hone is a process for honing finish-machined surfaces by the extrusion of an abrasive material (silly putty), which is forced through a restrictive fixture. The fabrication steps are described and production times are given.

  1. Underwater microdischarge in arranged microbubbles produced by electrolysis in electrolyte solution using fabric-type electrode

    SciTech Connect

    Sakai, Osamu; Kimura, Masaru; Tachibana, Kunihide; Shirafuji, Tatsuru

    2008-12-08

    Pulsed microdischarge was generated in microbubbles produced by electrolysis in an electrolyte solution without external gas feed by using a fabric-type electrode. The electrode structure not only allowed low-voltage ignition of the atmospheric-pressure discharge in hydrogen or oxygen containing microbubbles but also worked effectively in producing and holding the bubbles on its surface. The generation of reactive species was verified by optical emissions from the produced microplasmas, and their transport into the solution was monitored by the change in hydrogen concentration.

  2. A technique to produce aluminum color bands for avian research

    USGS Publications Warehouse

    Koronkiewicz, T.J.; Paxton, E.H.; Sogge, M.K.

    2005-01-01

    We developed a technique to produce metal (aluminum) color bands, in response to concerns about leg injuries caused by celluloid-plastic color bands applied to Willow Flycatchers (Empidonax traillii). The technique involves color-anodized aluminum bands (unnumbered blanks and federal numbered bands), with auto pin-striping tape and flexible epoxy sealant, to create a variety of solid, half- and triple-split colors. This allows for hundreds of unique, high-contrast color combinations. During six consecutive years of application, these colored metal bands have resisted color fade compared to conventional celluloid-plastic bands, and have reduced leg injuries in the flycatcher. Although not necessarily warranted for all color-banding studies, these metal bands may provide a lower-impact option for studies of species known to be impacted by plastic color bands.

  3. Retention of denture bases fabricated by three different processing techniques – An in vivo study

    PubMed Central

    Chalapathi Kumar, V. H.; Surapaneni, Hemchand; Ravikiran, V.; Chandra, B. Sarat; Balusu, Srilatha; Reddy, V. Naveen

    2016-01-01

    Aim: Distortion due to Polymerization shrinkage compromises the retention. To evaluate the amount of retention of denture bases fabricated by conventional, anchorized, and injection molding polymerization techniques. Materials and Methods: Ten completely edentulous patients were selected, impressions were made, and master cast obtained was duplicated to fabricate denture bases by three polymerization techniques. Loop was attached to the finished denture bases to estimate the force required to dislodge them by retention apparatus. Readings were subjected to nonparametric Friedman two-way analysis of variance followed by Bonferroni correction methods and Wilcoxon matched-pairs signed-ranks test. Results: Denture bases fabricated by injection molding (3740 g), anchorized techniques (2913 g) recorded greater retention values than conventional technique (2468 g). Significant difference was seen between these techniques. Conclusions: Denture bases obtained by injection molding polymerization technique exhibited maximum retention, followed by anchorized technique, and least retention was seen in conventional molding technique. PMID:27382542

  4. Porous titanium scaffolds fabricated using a rapid prototyping and powder metallurgy technique.

    PubMed

    Ryan, Garrett E; Pandit, Abhay S; Apatsidis, Dimitrios P

    2008-09-01

    One of the main issues in orthopaedic implant design is the fabrication of scaffolds that closely mimic the biomechanical properties of the surrounding bone. This research reports on a multi-stage rapid prototyping technique that was successfully developed to produce porous titanium scaffolds with fully interconnected pore networks and reproducible porosity and pore size. The scaffolds' porous characteristics were governed by a sacrificial wax template, fabricated using a commercial 3D-printer. Powder metallurgy processes were employed to generate the titanium scaffolds by filling around the wax template with titanium slurry. In the attempt to optimise the powder metallurgy technique, variations in slurry concentration, compaction pressure and sintering temperature were investigated. By altering the wax design template, pore sizes ranging from 200 to 400 microm were achieved. Scaffolds with porosities of 66.8 +/- 3.6% revealed compression strengths of 104.4+/-22.5 MPa in the axial direction and 23.5 +/- 9.6 MPa in the transverse direction demonstrating their anisotropic nature. Scaffold topography was characterised using scanning electron microscopy and microcomputed tomography. Three-dimensional reconstruction enabled the main architectural parameters such as pore size, interconnecting porosity, level of anisotropy and level of structural disorder to be determined. The titanium scaffolds were compared to their intended designs, as governed by their sacrificial wax templates. Although discrepancies in architectural parameters existed between the intended and the actual scaffolds, overall the results indicate that the porous titanium scaffolds have the properties to be potentially employed in orthopaedic applications. PMID:18556060

  5. Epoxy nanodielectrics fabricated with in situ and ex situ techniques

    SciTech Connect

    Tuncer, Enis; Polyzos, Georgios; Sauers, Isidor; James, David Randy; Ellis, Alvin R; More, Karren Leslie

    2012-01-01

    In this study, we report fabrication and characterisation of a nanocomposite system composed of a commercial resin and extremely small (several nanometres in diameter) titanium dioxide particles. Nanoparticles were synthesised in situ with particle nucleation occurring inside the resin matrix. In this nanodielectric fabrication method, the nanoparticle precursor was mixed to the resin solution, and the nanoparticles were in situ precipitated. Note that no high shear mixing equipment was needed to improve particle dispersion - nanoparticles were distributed in the polymer matrix uniformly since particle nucleation occurs uniformly throughout the matrix. The properties of in situ nanodielectrics are compared to the unfilled resin and an ex situ nanocomposite. We anticipate that the presented in situ nanocomposite would be employed in high-temperature superconductivity applications. In additions, the improvement shown in the dielectric breakdown indicates that conventional high-voltage components and systems can be reduced in size with novel nanodielectrics.

  6. Fabrication of a wettability-gradient surface on copper by screen-printing techniques

    NASA Astrophysics Data System (ADS)

    Huang, Ding-Jun; Leu, Tzong-Shyng

    2015-08-01

    In this study, a screen-printing technique is utilized to fabricate a wettability-gradient surface on a copper substrate. The pattern definitions on the copper surface were freely fabricated to define the regions with different wettabilities, for which the printing definition technique was developed as an alternative to the existing costly photolithography techniques. This fabrication process using screen printing in tandem with chemical modification methods can easily realize an excellent wettability-gradient surface with superhydrophobicity and superhydrophilicity. Surface analyses were performed to characterize conditions in some fabrication steps. A water droplet movement sequence is provided to clearly demonstrate the droplet-driving effectiveness of the fabricated gradient surface. The droplet-driving efficiency offers a promising solution for condensation heat transfer applications in the foreseeable future.

  7. A Novel Porous Scaffold Fabrication Technique for Epithelial and Endothelial Tissue Engineering

    PubMed Central

    McHugh, Kevin J.; Tao, Sarah L.; Saint-Geniez, Magali

    2014-01-01

    Porous scaffolds have the ability to minimize transport barriers for both two- (2D) and three-dimensional tissue engineering. However, current porous scaffolds may be non-ideal for 2D tissues such as epithelium due to inherent fabrication-based characteristics. While 2D tissues require porosity to support molecular transport, pores must be small enough to prevent cell migration into the scaffold in order to avoid non-epithelial tissue architecture and compromised function. Though electrospun meshes are the most popular porous scaffolds used today, their heterogeneous pore size and intense topography may be poorly-suited for epithelium. Porous scaffolds produced using other methods have similar unavoidable limitations, frequently involving insufficient pore resolution and control, which make them incompatible with 2D tissues. In addition, many of these techniques require an entirely new round of process development in order to change material or pore size. Herein we describe “pore casting,” a fabrication method that produces flat scaffolds with deterministic pore shape, size, and location that can be easily altered to accommodate new materials or pore dimensions. As proof-of-concept, pore-cast poly(ε-caprolactone) (PCL) scaffolds were fabricated and compared to electrospun PCL in vitro using canine kidney epithelium, human colon epithelium, and human umbilical vein endothelium. All cell types demonstrated improved morphology and function on pore-cast scaffolds, likely due to reduced topography and universally small pore size. These results suggest that pore casting is an attractive option for creating 2D tissue engineering scaffolds, especially when the application may benefit from well-controlled pore size or architecture. PMID:23625319

  8. A Simplified Technique for Fabrication of Orbital Prosthesis

    PubMed Central

    Thakral, G.K.; Mohapatra, Abhilash; Seth, Jyotsna; Vashisht, Pallavi

    2014-01-01

    Eye is a vital organ not only for vision, but also an important component of facial expression, and over-all personality of a person. Loss of eye, apart from leading to impaired vision has a crippling effect on the psychology of the patient. Prosthodontic rehabilitation of such cases includes fabrication of prosthesis by acrylic resin, silicone and implants. However, not all patients are willing to use implants for maxillofacial rehabilitation. Therefore, a custom made orbital prosthesis serves as an affordable and satisfactory alternative. PMID:25121068

  9. Single intrinsic Josephson junction with double-sided fabrication technique

    NASA Astrophysics Data System (ADS)

    You, L. X.; Torstensson, M.; Yurgens, A.; Winkler, D.; Lin, C. T.; Liang, B.

    2006-05-01

    We make stacks of intrinsic Josephson junctions (IJJs) embedded in the bulk of very thin (d⩽100nm) Bi2Sr2CaCu2O8+x single crystals. By precisely controlling the etching depth during the double-sided fabrication process, the stacks can be reproducibly tailor-made to be of any microscopic height (0-9nm

  10. Development of improved electroforming technique. [for fabricating regeneratively cooled thrust chambers

    NASA Technical Reports Server (NTRS)

    Mccandles, L. C.; Davies, L. G.

    1973-01-01

    Techniques were studied to reinforce or strengthen electroformed nickel to allow a fuller utilization of electroforming as a reliable and low cost fabrication technique for regenerately cooled thrust chambers. Techniques for wire wrapping while electrodepositing were developed that can result in a structurally strong wall with less weight than a conventional electroformed wall. Also a technique of codepositing submicron sized THO2 particles with the nickel to form a dispersion strengthened structure was evaluated. The standard nickel cylinders exhibited an average hoop strength of 80,000 psi with a yield strength of 65,000 psi and a modulus of 25.6 x 10 to the 6th power psi. The as produced dispersion strengthened nickel showed a hoop strength of 97,000 psi with a yield strength of 67,000 psi. This is an increase of 17,000 psi or 21% over the standard nickel hoop strength. The wire wrapping cylinders showed an increased strength over the standard nickel test samples of 26,000 to 66,800 psi which is in the range of 26 to 104% increase in strength over the base standard nickel. These latter test results are indicative of a volume percent wire reinforcement from 15 to 31. The measured hoop strengths agree with calculated composite strengths based upon rule of mixtures.

  11. Advanced fabrication techniques for hydrogen-cooled engine structures. Final report, October 1975-June 1982

    SciTech Connect

    Buchmann, O.A.; Arefian, V.V.; Warren, H.A.; Vuigner, A.A.; Pohlman, M.J.

    1985-11-01

    Described is a program for development of coolant passage geometries, material systems, and joining processes that will produce long-life hydrogen-cooled structures for scramjet applications. Tests were performed to establish basic material properties, and samples constructed and evaluated to substantiate fabrication processes and inspection techniques. Results of the study show that the basic goal of increasing the life of hydrogen-cooled structures two orders of magnitude relative to that of the Hypersonic Research Engine can be reached with available means. Estimated life is 19000 cycles for the channels and 16000 cycles for pin-fin coolant passage configurations using Nickel 201. Additional research is required to establish the fatigue characteristics of dissimilar-metal coolant passages (Nickel 201/Inconel 718) and to investigate the embrittling effects of the hydrogen coolant.

  12. Two-step fabrication technique of gold tips for use in point-contact spectroscopy

    SciTech Connect

    Narasiwodeyar, S.; Dwyer, M.; Liu, M.; Park, W. K. Greene, L. H.

    2015-03-15

    For a successful point-contact spectroscopy (PCS) measurement, metallic tips of proper shape and smoothness are essential to ensure the ballistic nature of a point-contact junction. Until recently, the fabrication of Au tips suitable for use in point-contact spectroscopy has remained more of an art involving a trial and error method rather than an automated scientific process. To address these issues, we have developed a technique with which one can prepare high quality Au tips reproducibly and systematically. It involves an electronic control of the driving voltages used for an electrochemical etching of a gold wire in a HCl-glycerol mixture or a HCl solution. We find that a stopping current, below which the circuit is set to shut off, is a single very important parameter to produce an Au tip of desired shape. We present detailed descriptions for a two-step etching process for Au tips and also test results from PCS measurements using them.

  13. Optical waveguides in Er:LiNbO3 fabricated by different techniques - A comparison

    NASA Astrophysics Data System (ADS)

    Cajzl, Jakub; Nekvindová, Pavla; Macková, Anna; Malinský, Petr; Oswald, Jiří; Staněk, Stanislav; Vytykáčová, Soňa; Špirková, Jarmila

    2016-03-01

    We report on the comparison of three techniques used for the fabrication of optical waveguides in erbium doped lithium niobate crystal substrates (Er:LiNbO3). The techniques include ion in-diffusion from a titanium metal layer, annealed proton exchange (APE), and He+ ion implantation. The main focus of the work was placed on the investigation of the influence of the used optical waveguides fabrication techniques on the structural and luminescence properties of Er:LiNbO3 substrates. The results have shown that none of the used optical-waveguide-fabrication techniques significantly affect the position of erbium in the host crystal structure. It turned out, however, that the fabrication process affected luminescence intensities of the characteristic luminescence bands of erbium ions - the most significant decrease in the luminescence intensity was observed in the Ti-indiffused waveguides.

  14. Virtual techniques for designing and fabricating a retainer.

    PubMed

    Nasef, Ahmed A; El-Beialy, Amr R; Mostafa, Yehya A

    2014-09-01

    The purpose of this article was to report a procedure for using 3-dimensional cone-beam computed tomography imaging, computer-aided design, computer-aided manufacturing, and rapid prototyping to design and produce a retainer. PMID:25172262

  15. High Contrast Internal and External Coronagraph Masks Produced by Various Techniques

    NASA Technical Reports Server (NTRS)

    Balasubramanian, Kunjithapatha; Wilson, Daniel; White, Victor; Muller, Richard; Dickie, Matthew; Yee, Karl; Ruiz, Ronald; Shaklan, Stuart; Cady, Eric; Kern, Brian; Belikov, Ruslan; Guyon, Olivier; Kasdin, N. Jeremy

    2013-01-01

    Masks for high contrast internal and external coronagraphic imaging require a variety of masks depending on different architectures to suppress star light. Various fabrication technologies are required to address a wide range of needs including gradient amplitude transmission, tunable phase profiles, ultra-low reflectivity, precise small scale features, and low-chromaticity. We present the approaches employed at JPL to produce pupil plane and image plane coronagraph masks, and lab-scale external occulter type masks by various techniques including electron beam, ion beam, deep reactive ion etching, and black silicon technologies with illustrative examples of each. Further development is in progress to produce circular masks of various kinds for obscured aperture telescopes.

  16. A blanket design, apparatus, and fabrication techniques for the mass production of multilayer insulation blankets for the Superconducting Super Collider

    SciTech Connect

    Gonczy, J.D.; Boroski, W.N.; Niemann, R.C.; Otavka, J.G.; Ruschman, M.K.; Schoo, C.J.

    1989-09-01

    The multilayer insulation (MLI) system for the Superconducting Super Collider (SSC) consists of full cryostat length assemblies of aluminized polyester film fabricated in the form of blankets and installed as blankets to the 4.5K cold mass and the 20K and 80K thermal radiation shields. Approximately 40,000 MLI blankets will be required in the 10,000 cryogenic devices comprising the SSC accelerator. Each blanket is nearly 17 meters long and 1.8 meters wide. This paper reports the blanket design, an apparatus, and the fabrication method used to mass produce pre-fabricated MLI blankets. Incorporated in the blanket design are techniques which automate quality control during installation of the MLI blankets in the SSC cryostat. The apparatus and blanket fabrication method insure consistency in the mass produced blankets by providing positive control of the dimensional parameters which contribute to the thermal performance of the MLI blanket. By virtue of the fabrication process, the MLI blankets have inherent features of dimensional stability three-dimensional uniformity, controlled layer density, layer-to-layer registration, interlayer cleanliness, and interlayer material to accommodate thermal contraction differences. 11 refs., 6 figs., 1 tab.

  17. Processing Techniques Developed to Fabricate Lanthanum Titanate Piezoceramic Material for High-Temperature Smart Structures

    NASA Technical Reports Server (NTRS)

    Goldsby, Jon C.; Farmer, Serene C.; Sayir, Ali

    2004-01-01

    Piezoelectric ceramic materials are potential candidates for use as actuators and sensors in intelligent gas turbine engines. For piezoceramics to be applied in gas turbine engines, they will have to be able to function in temperatures ranging from 1000 to 2500 F. However, the maximum use temperature for state-of-the-art piezoceramic materials is on the order of 300 to 400 F. Research activities have been initiated to develop high-temperature piezoceramic materials for gas turbine engine applications. Lanthanum titanate has been shown to have high-temperature piezoelectric properties with Curie temperatures of T(sub c) = 1500 C and use temperatures greater than 1000 C. However, the fabrication of lanthanum titanate poses serious challenges because of the very high sintering temperatures required for densification. Two different techniques have been developed at the NASA Glenn Research Center to fabricate dense lanthanum titanate piezoceramic material. In one approach, lower sintering temperatures were achieved by adding yttrium oxide to commercially available lanthanum titanate powder. Addition of only 0.1 mol% yttrium oxide lowered the sintering temperature by as much as 300 C, to just 1100 C, and dense lanthanum titanate was produced by pressure-assisted sintering. The second approach utilized the same commercially available powders but used an innovative sintering approach called differential sintering, which did not require any additive.

  18. Structures and fabrication techniques for solid state electrochemical devices

    DOEpatents

    Visco, Steven J.; Jacobson, Craig P.; DeJonghe, Lutgard C.

    2006-10-10

    Low-cost, mechanically strong, highly electronically conductive porous substrates and associated structures for solid-state electrochemical devices, techniques for forming these structures, and devices incorporating the structures provide solid state electrochemical device substrates of novel composition and techniques for forming thin electrode/membrane/electrolyte coatings on the novel or more conventional substrates. In particular, in one aspect the invention provides techniques for co-firing of device substrate (often an electrode) with an electrolyte or membrane layer to form densified electrolyte/membrane films 5 to 20 microns thick. In another aspect, densified electrolyte/membrane films 5 to 20 microns thick may be formed on a pre-sintered substrate by a constrained sintering process. In some cases, the substrate may be a porous metal, alloy, or non-nickel cermet incorporating one or more of the transition metals Cr, Fe and Cu, or alloys thereof.

  19. Structures and fabrication techniques for solid state electrochemical devices

    DOEpatents

    Visco, Steven J.; Jacobson, Craig P.; DeJonghe, Lutgard C.

    2003-08-12

    Provided are low-cost, mechanically strong, highly electronically conductive porous substrates and associated structures for solid-state electrochemical devices, techniques for forming these structures, and devices incorporating the structures. The invention provides solid state electrochemical device substrates of novel composition and techniques for forming thin electrode/membrane/electrolyte coatings on the novel or more conventional substrates. In particular, in one embodiment the invention provides techniques for co-firing of device substrate (often an electrode) with an electrolyte or membrane layer to form densified electrolyte/membrane films 5 to 20 microns thick. In another embodiment, densified electrolyte/membrane films 5 to 20 microns thick may be formed on a pre-sintered substrate by a constrained sintering process. In some cases, the substrate may be a porous metal, alloy, or non-nickel cermet incorporating one or more of the transition metals Cr, Fe, Cu and Ag, or alloys thereof.

  20. Structures And Fabrication Techniques For Solid State Electrochemical Devices

    DOEpatents

    Visco, Steven J.; Jacobson, Craig P.; DeJonghe, Lutgard C.

    2005-12-27

    Provided are low-cost, mechanically strong, highly electronically conductive porous substrates and associated structures for solid-state electrochemical devices, techniques for forming these structures, and devices incorporating the structures. The invention provides solid state electrochemical device substrates of novel composition and techniques for forming thin electrode/membrane/electrolyte coatings on the novel or more conventional substrates. In particular, in one embodiment the invention provides techniques for co-firing of device substrate (often an electrode) with an electrolyte or membrane layer to form densified electrolyte/membrane films 5 to 20 microns thick. In another embodiment, densified electrolyte/membrane films 5 to 20 microns thick may be formed on a pre-sintered substrate by a constrained sintering process. In some cases, the substrate may be a porous metal, alloy, or non-nickel cermet incorporating one or more of the transition metals Cr, Fe, Cu and Ag, or alloys thereof.

  1. Simple multimask technique for fabrication of high-resolution polymer structures

    NASA Astrophysics Data System (ADS)

    Cowin, Michael A.; Penty, Richard V.; White, Ian H.

    2000-05-01

    The performance of many integrated photonic deices is often determined by the accuracy by which the structure can be defined and ultimately fabricated. However the manufacture of highly defined vertices in photonic structures is often limited by the mask quality and by the limited resolution obtainable by standard photolithography. A simplified fabrication technique is presented here, that offers advantages over previously reported methods for the fabrication of highly defined vertices in polymeric integrated optical components so overcoming these limiting factors. The application of this technique for the fabrication of 2D integrated optical wavelength division multiplexing components is demonstrated. The possible application of this component to the low cost datacom market is also reviewed and compared to competitive technologies. The advantages of the technique is discussed and the improved resolution obtainable in comparison to standard single mask photolithography is illustrated.

  2. Mass-producible and efficient optical antennas with CMOS-fabricated nanometer-scale gap.

    PubMed

    Seok, Tae Joon; Jamshidi, Arash; Eggleston, Michael; Wu, Ming C

    2013-07-15

    Optical antennas have been widely used for sensitive photodetection, efficient light emission, high resolution imaging, and biochemical sensing because of their ability to capture and focus light energy beyond the diffraction limit. However, widespread application of optical antennas has been limited due to lack of appropriate methods for uniform and large area fabrication of antennas as well as difficulty in achieving an efficient design with small mode volume (gap spacing < 10nm). Here, we present a novel optical antenna design, arch-dipole antenna, with optimal radiation efficiency and small mode volume, 5 nm gap spacing, fabricated by CMOS-compatible deep-UV spacer lithography. We demonstrate strong surface-enhanced Raman spectroscopy (SERS) signal with an enhancement factor exceeding 108 from the arch-dipole antenna array, which is two orders of magnitude stronger than that from the standard dipole antenna array fabricated by e-beam lithography. Since the antenna gap spacing, the critical dimension of the antenna, can be defined by deep-UV lithography, efficient optical antenna arrays with nanometer-scale gap can be mass-produced using current CMOS technology. PMID:23938507

  3. Fabrication of a microlens array in BK7 through laser ablation and thermal treatment techniques

    NASA Astrophysics Data System (ADS)

    Blanco, M.; Nieto, D.; Flores-Arias, M. T.

    2015-04-01

    We propose a laser-based method for fabricating microlens on borosilicate glass substrates. The technique is composed by a laser direct-write technique using a Nd : YVO4 for fabricating the microlens arrays and a post thermal treatment with a CO2 laser for improving its morphological and optical properties. The proposed technique will allow us to obtain microlenses with a broad range of diameters (50μm-500μm) and focal lengths (1mm-5mm). By combining laser direct-write and the thermal treatment assisted by a CO2 laser, we are able to obtain good quality elements.

  4. Hybrid sample-inverted reflow and soft-lithography technique for fabrication of conicoid microlens arrays.

    PubMed

    He, Miao; Yuan, Xiaocong; Bu, Jing; Cheong, Wai Chye

    2005-07-01

    We report a cost-effective fabrication method, with a combination of the sample-inverted reflow technique and the soft-lithography replication method, to fabricate conicoid refractive microlens arrays (MLAs), including hyperboloid, paraboloid, and ellipsoid MLAs in inorganic-organic hybrid SiO2-ZrO2 solgel material. The fabrication procedures involve two basic steps. First, a master of the conicoid MLA was made in photoresist by the sample-inverted reflow technique. Second, we built a negative mold of the master by casting polydimethylsiloxane (PDMS) onto a silicone elastomer against the master, and then the profile was imprinted onto the solgel glass. As a result, the fabricated solgel MLAs have been obtained with excellent smooth profiles, having negligible discrepancies from the profiles of ideal conicoid MLAs. PMID:16004061

  5. Hybrid sample-inverted reflow and soft-lithography technique for fabrication of conicoid microlens arrays

    NASA Astrophysics Data System (ADS)

    He, Miao; Yuan, Xiaocong; Bu, Jing; Chye Cheong, Wai

    2005-07-01

    We report a cost-effective fabrication method, with a combination of the sample-inverted reflow technique and the soft-lithography replication method, to fabricate conicoid refractive microlens arrays (MLAs), including hyperboloid, paraboloid, and ellipsoid MLAs in inorganic-organic hybrid SiO2-ZrO2 solgel material. The fabrication procedures involve two basic steps. First, a master of the conicoid MLA was made in photoresist by the sample-inverted reflow technique. Second, we built a negative mold of the master by casting polydimethylsiloxane (PDMS) onto a silicone elastomer against the master, and then the profile was imprinted onto the solgel glass. As a result, the fabricated solgel MLAs have been obtained with excellent smooth profiles, having negligible discrepancies from the profiles of ideal conicoid MLAs.

  6. An Alternative Technique for Fabrication of Frameworks in an Immediate Loading Implant Fixed Mandibular Prosthesis

    PubMed Central

    Paleari, André Gustavo; Presoto, Cristina Dupim; Vasconcelos, Juliano Alencar; Nunes Reis, José Maurício dos Santos; Pinelli, Lígia Antunes Pereira; Tavares da Silva, Regina Helena Barbosa; Quishida, Cristiane Campos Costa

    2015-01-01

    The oral rehabilitation of edentulous patients with immediate loading has become a safe procedure with high predictability. The success is related to immediate fabrication of a passive fit framework to attach the implants. Based on these considerations, this case report shows an alternative technique for mandibular rehabilitation using implants immediately loaded, where the framework was fabricated using cylinders with internal reinforcement and precast pieces, electrowelding, and conventional welding providing esthetics and function to the patient in a short period of time. PMID:25628899

  7. Study of the laser scribing of molybdenum thin films fabricated using different deposition techniques

    NASA Astrophysics Data System (ADS)

    Schneller, Eric; Dhere, Neelkanth G.; Shimada, Juliana; Kar, Aravinda

    2013-09-01

    Monolithic cell interconnection is a technique used in solar devices to allow for interconnection of adjacent cells through patterning of the thin films during fabrication. In the case of CuIn1-xGaxSe2-ySy (CIGS) solar cells, Molybdenum is commonly used as the back contact. Patterning of this layer is required in the interconnection scheme to electrically isolate adjacent cells. Laser scribing has been adopted for patterning of this layer. This paper reports on the effect of the molybdenum thin film deposition technique, and the resulting film properties, on the characteristic of the laser scribe. Films were deposited using DC magnetron sputtering over a range of working gas pressures and powers as well as in single and multilayer configurations. It was found that the residual stress within the film lead to significantly different laser ablation processes. This required independent tuning of the laser processing parameters to create a clean, defect free scribe for different samples. Experimentation was carried out using both film-side and glass-side processing. It was shown that glass-side processing leads to a reduction in cracks and delamination originating from the scribe. The processing conditions that produced successful scribe lines for the various films are presented and discussed.

  8. Ultrasonic ablation as a novel technique for producing pure aluminium nanoparticles dispersed in different liquids for different applications

    NASA Astrophysics Data System (ADS)

    Ismail, Yasser A. M.; Kishi, Naoki; Soga, Tetsuo

    2015-07-01

    In this paper, we introduce a novel physical method for producing surfactant-free aluminium nanoparticles (Al NPs) by irradiating ultrasonic waves on Al thin films immersed in different liquids used for different applications. We suggest naming this technique “ultrasonic ablation”. Our method has many advantages compared with other chemical and physical methods such as (1) fabrication of Al NPs using low-cost and easy procedures, (2) fabrication of pure Al NPs without any chemical additives, (3) fabrication of Al NPs dispersed in different liquids used for different applications, and (4) fabrication of individual Al NPs without aggregations. We have prepared Al NPs in 1,2-dichlorobenzene, which is used as a solvent for preparing active layer solutions of organic solar cells (OSCs), poly(3,4-ethylenedioxythiophene)-blend-poly(styrene sulfonate) (PEDOT:PSS), which is a representative aqueous solution used as a buffer layer in OSCs, and ethanol, which is a representative polar solvent used for different applications. Scanning electron microscopy (SEM) and optical absorption techniques have verified the fabrication of individual and surfactant-free Al NPs dispersed in different liquids that can be safely used in different applications.

  9. Fabrication of ultra-fine grained aluminium tubes by RTES technique

    SciTech Connect

    Jafarzadeh, H. Abrinia, K.

    2015-04-15

    Recently, repetitive tube expansion and shrinking have been exploited as a means for producing ultra-fine grained and nano-crystalline microstructures for magnesium alloy tubes. This method includes two different half-cycles and was based on pressing a tubular part through an angular channel die with two shear zones. Since the aluminium alloys are the most widely used materials in industries, in this study, repetitive tube expansion and shrinking as a new severe plastic deformation technique was applied to commercially pure aluminium for fabricating ultra-fine grained aluminium tubes for the first time and the ability of this process in significant grain refinement is determined even after single cycle. Transmission electron microscopy and X-ray diffraction were used to evaluate the microstructure of the repetitive tube expansion and shrinking processed materials and the examinations showed ultra-fine grains with the average grain size of 320 nm after one cycle of repetitive tube expansion and shrinking. The yield strength, ultimate tensile strength increased notably by the factor of 2.17 and 1.27 respectively, after one cycle of repetitive tube expansion and shrinking, whereas the elongation to failure as well as the uniform elongation decreased. Furthermore, micro-hardness distribution through the part's section proposed the hardness increasing to ~ 55 HV from the initial value of ~ 28 HV after one cycle of repetitive tube expansion and shrinking. - Highlights: • RTES was introduced for fabricating the UFGed AA1050 tubes for the first time. • Nano-grained AA1050 tube was obtained by RTES process. • Grain size of ~ 320 nm was obtained after two half-cycles of RTES process. • Yield and ultimate strength increased by the factor of 2.17 and 1.27 respectively. • The microhardness increased to ~ 55 HV from the initial value of ~ 28 HV.

  10. Fabrication of Large Size Ex Vivo-Produced Oral Mucosal Equivalents for Clinical Application.

    PubMed

    Kato, Hiroko; Marcelo, Cynthia L; Washington, James B; Bingham, Eve L; Feinberg, Stephen E

    2015-09-01

    The soft tissue reconstruction of significant avulsed and/or surgically created tissue defects requires the ability to manufacture substantial soft tissue constructs for repair of the resulting wounds. In this study, we detail the issues that need to be addressed in upsizing the manufacture of larger tissue-engineered devices (ex vivo-produced oral mucosa equivalent [EVPOME]) in vitro from a methodology previously used for smaller constructs. The larger-sized EVPOME, consisting of autologous human oral keratinocytes and a dermal substitute, AlloDerm(®), was fabricated for the purpose of reconstructing large clinical defects. Regulated as an autologous somatic cell therapy product, the fabrication process abided by current Good Manufacturing Practices and current Good Tissue Practices as required by the Center for Biologics Evaluation and Research (CBER) of the United States Food and Drug Administration (FDA). Successful fabrication of large EVPOMEs utilized a higher cell seeding density (5.3×10(5) cells/cm(2)) with a relatively thinner AlloDerm, ranging from 356.6 to 508.0 μm in thickness. During the air-liquid interface culture, the thickness of the scaffold affected the medium diffusion rate, which, in turn, resulted in changes of epithelial stratification. Histologically, keratinocyte progenitor (p63), proliferation (Ki-67), and late differentiation marker (filaggrin) expression showed differences correlating with the expression of glucose transporter-1 (GLUT1) in the EVPOMEs from the thickest (550-1020 μm) to the thinnest (228.6-330.2 μm) AlloDerm scaffold. Glucose consumption and 2-deoxyglucose (2DG) uptake showed direct correlation with scaffold thickness. The scaffold size and thickness have an impact on the cellular phenotype and epithelial maturation in the manufacturing process of the EVPOME due to the glucose accessibility influenced by the diffusion rate. These outcomes provide basic strategies to manufacture a large-sized, healthy EVPOME

  11. New finishing possibilities for producing durable multifunctional cotton/wool and viscose/wool blended fabrics.

    PubMed

    Ibrahim, N A; El-Zairy, M R; Eid, B M; El-Zairy, E M R; Emam, E M

    2015-03-30

    This research work focuses on the development of a one-bath functional finishing procedure for imparting durable multifunctional properties such as easy care, soft-hand, antibacterial and/or ultra violet (UV) protection to cotton/wool and viscose/wool blends using diverse finishing combinations and formulations. In this study finishing agents such as reactant resin, silicon softeners, 4-hydroxybenzophenone, triclosan, and pigment colorant were selected using magnesium chloride/citric acid as a mixed catalyst and the pad-dry microwave fixation technique. The results reveal that enhancement in the imparted functional properties are governed by type of the finished substrate as well as nature and concentration of finishing formulation components. The finished fabrics still retained high level of functionalities even after 15 consecutive laundering. Surface morphology and composition of selected samples were investigated using scan electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDX) analysis. The mode of interactions was also investigated. Practical applications for multifunctionlization of cellulose/wool blended fabrics are possible using these sorts of proper finishing formulations and unique finishing application method. PMID:25563959

  12. Biofabrication under fluorocarbon: a novel freeform fabrication technique to generate high aspect ratio tissue-engineered constructs.

    PubMed

    Blaeser, Andreas; Duarte Campos, Daniela F; Weber, Michael; Neuss, Sabine; Theek, Benjamin; Fischer, Horst; Jahnen-Dechent, Willi

    2013-10-01

    Bioprinting is a recent development in tissue engineering, which applies rapid prototyping techniques to generate complex living tissues. Typically, cell-containing hydrogels are dispensed layer-by-layer according to a computer-generated three-dimensional model. The lack of mechanical stability of printed hydrogels hinders the fabrication of high aspect ratio constructs. Here we present submerged bioprinting, a novel technique for freeform fabrication of hydrogels in liquid fluorocarbon. The high buoyant density of fluorocarbons supports soft hydrogels by floating. Hydrogel constructs of up to 30-mm height were generated. Using 3% (w/v) agarose as the hydrogel and disposable syringe needles as nozzles, the printer produced features down to 570-μm diameter with a lateral dispensing accuracy of 89 μm. We printed thin-walled hydrogel cylinders measuring 4.8 mm in height, with an inner diameter of ∼2.9 mm and a minimal wall thickness of ∼650 μm. The technique was successfully applied in printing a model of an arterial bifurcation. We extruded under fluorocarbon, cellularized alginate tubes with 5-mm outer diameter and 3-cm length. Cells grew vigorously and formed clonal colonies within the 7-day culture period. Submerged bioprinting thus seems particularly suited to fabricate hollow structures with a high aspect ratio like vascular grafts for cardiovascular tissue engineering as well as branching or cantilever-like structures, obviating the need for a solid support beneath the overhanging protrusions. PMID:24083093

  13. Biofabrication Under Fluorocarbon: A Novel Freeform Fabrication Technique to Generate High Aspect Ratio Tissue-Engineered Constructs

    PubMed Central

    Blaeser, Andreas; Duarte Campos, Daniela F.; Weber, Michael; Neuss, Sabine; Theek, Benjamin; Fischer, Horst

    2013-01-01

    Abstract Bioprinting is a recent development in tissue engineering, which applies rapid prototyping techniques to generate complex living tissues. Typically, cell-containing hydrogels are dispensed layer-by-layer according to a computer-generated three-dimensional model. The lack of mechanical stability of printed hydrogels hinders the fabrication of high aspect ratio constructs. Here we present submerged bioprinting, a novel technique for freeform fabrication of hydrogels in liquid fluorocarbon. The high buoyant density of fluorocarbons supports soft hydrogels by floating. Hydrogel constructs of up to 30-mm height were generated. Using 3% (w/v) agarose as the hydrogel and disposable syringe needles as nozzles, the printer produced features down to 570-μm diameter with a lateral dispensing accuracy of 89 μm. We printed thin-walled hydrogel cylinders measuring 4.8 mm in height, with an inner diameter of ∼2.9 mm and a minimal wall thickness of ∼650 μm. The technique was successfully applied in printing a model of an arterial bifurcation. We extruded under fluorocarbon, cellularized alginate tubes with 5-mm outer diameter and 3-cm length. Cells grew vigorously and formed clonal colonies within the 7-day culture period. Submerged bioprinting thus seems particularly suited to fabricate hollow structures with a high aspect ratio like vascular grafts for cardiovascular tissue engineering as well as branching or cantilever-like structures, obviating the need for a solid support beneath the overhanging protrusions. PMID:24083093

  14. Development of Core Cladding Fabrication Techniques for Phase I Fission Propulsion Systems

    NASA Technical Reports Server (NTRS)

    Salvail, Patrick G.; Reid, Robert S.; Ring, Peter J.; Gentz, Steven J. (Technical Monitor)

    2001-01-01

    Phase I fission propulsion systems focus on safety, timely development, and affordability. Prototype and flight units can be tested at full thrust, using resistance heaters to closely simulate heat from a fission reaction. In Phase I ground testing, one goal is to establish a reliable and affordable manufacturing technique for fabricating a flight-like core. A refractory metal (Mo) has been suggested for the core substrate, primarily due to the existence of a significant database for Mo/LJ02 fuel. The core can be fabricated by bundling Mo tubes with a bonding system that meets preliminary test goals. These criteria include materials compatibility, ability to maintain thermal and structural integrity during 10,000 hours of operation, and fabrication with existing facilities. This paper describes an effort to investigate several fabrication techniques in a cost-effective manner. First, inexpensive materials were tested at low temperatures to determine the relative effectiveness of such techniques as welding, brazing, plating, and vacuum plasma spraying (VPSing). Promising techniques were chosen for further evaluation, including thermal and structural studies, using ceramic tubing at intermediate temperatures. The most desirable technique will be tested on actual Mo tubing at anticipated operating temperatures. This work is being performed by the National Aeronautics & Space Administration (NASA) at George C. Marshall Space Flight Center (MSFC), Los Alamos National Laboratory (LANL), and Advanced Methods & Materials (AMM), Inc.

  15. Fabric phase sorptive extraction: Two practical sample pretreatment techniques for brominated flame retardants in water.

    PubMed

    Huang, Guiqi; Dong, Sheying; Zhang, Mengfei; Zhang, Haihan; Huang, Tinglin

    2016-09-15

    Sample pretreatment is the critical section for residue monitoring of hazardous pollutants. In this paper, using the cellulose fabric as host matrix, three extraction sorbents such as poly (tetrahydrofuran) (PTHF), poly (ethylene glycol) (PEG) and poly (dimethyldiphenylsiloxane) (PDMDPS), were prepared on the surface of the cellulose fabric. Two practical extraction techniques including stir bar fabric phase sorptive extraction (stir bar-FPSE) and magnetic stir fabric phase sorptive extraction (magnetic stir-FPSE) have been designed, which allow stirring of fabric phase sorbent during the whole extraction process. In the meantime, three brominated flame retardants (BFRs) [tetrabromobisphenol A (TBBPA), tetrabromobisphenol A bisallylether (TBBPA-BAE), tetrabromobisphenol A bis(2,3-dibromopropyl)ether (TBBPA-BDBPE)] in the water sample were selected as model analytes for the practical evaluation of the proposed two techniques using high-performance liquid chromatography (HPLC). Moreover, various experimental conditions affecting extraction process such as the type of fabric phase, extraction time, the amount of salt and elution conditions were also investigated. Due to the large sorbent loading capacity and unique stirring performance, both techniques possessed high extraction capability and fast extraction equilibrium. Under the optimized conditions, high recoveries (90-99%) and low limits of detection (LODs) (0.01-0.05 μg L(-1)) were achieved. In addition, the reproducibility was obtained by evaluating the intraday and interday precisions with relative standard deviations (RSDs) less than 5.1% and 6.8%, respectively. The results indicated that two pretreatment techniques were promising and practical for monitoring of hazardous pollutants in the water sample. Due to low solvent consumption and high repeated use performance, proposed techniques also could meet green analytical criteria. PMID:27300591

  16. Photographic and drafting techniques simplify method of producing engineering drawings

    NASA Technical Reports Server (NTRS)

    Provisor, H.

    1968-01-01

    Combination of photographic and drafting techniques has been developed to simplify the preparation of three dimensional and dimetric engineering drawings. Conventional photographs can be converted to line drawings by making copy negatives on high contrast film.

  17. Nano-fabricated superconducting radio-frequency composites, method for producing nano-fabricated superconducting rf composites

    DOEpatents

    Norem, James H.; Pellin, Michael J.

    2013-06-11

    Superconducting rf is limited by a wide range of failure mechanisms inherent in the typical manufacture methods. This invention provides a method for fabricating superconducting rf structures comprising coating the structures with single atomic-layer thick films of alternating chemical composition. Also provided is a cavity defining the invented laminate structure.

  18. High frequency PMN-PT single crystal focusing transducer fabricated by a mechanical dimpling technique.

    PubMed

    Chen, Y; Lam, K H; Zhou, D; Cheng, W F; Dai, J Y; Luo, H S; Chan, H L W

    2013-02-01

    High frequency (∼30MHz and ∼80MHz) focusing ultrasound transducers were fabricated using a PMN-0.28PT single crystal by a mechanical dimpling technique. The dimpled single crystal was used as an active element for the focusing transducer. Compared with a plane transducer, the focusing transducer fabricated with a dimpled active element exhibits much broader bandwidth and higher sensitivity. Besides, a high quality image can be obtained by the 30MHz focusing transducer, in which the -6dB axial and lateral resolution is 27μm and 139μm, respectively. These results prove that the dimpling technique is capable to fabricate the high frequency focusing transducers with excellent performance for imaging applications. PMID:22944074

  19. A new fabrication technique for back-to-back varactor diodes

    NASA Technical Reports Server (NTRS)

    Smith, R. Peter; Choudhury, Debabani; Martin, Suzanne; Frerking, Margaret A.; Liu, John K.; Grunthaner, Frank A.

    1992-01-01

    A new varactor diode process has been developed in which much of the processing is done from the back of an extremely thin semiconductor wafer laminated to a low-dielectric substrate. Back-to-back BNN diodes were fabricated with this technique; excellent DC and low-frequency capacitance measurements were obtained. Advantages of the new technique relative to other techniques include greatly reduced frontside wafer damage from exposure to process chemicals, improved capability to integrate devices (e.g. for antenna patterns, transmission lines, or wafer-scale grids), and higher line yield. BNN diodes fabricated with this technique exhibit approximately the expected capacitance-voltage characteristics while showing leakage currents under 10 mA at voltages three times that needed to deplete the varactor. This leakage is many orders of magnitude better than comparable Schottky diodes.

  20. An innovative impression technique for fabrication of a custom made ocular prosthesis

    PubMed Central

    Tripuraneni, Sunil Chandra; Vadapalli, Sriharsha Babu; Ravikiran, P; Nirupama, N

    2015-01-01

    Various impression and fitting techniques have been described in the past for restoring ocular defects. The present article describes a new direct impression technique for recording and rehabilitating ocular defects, by custom-made ocular prosthesis. All the techniques described in the history, mainly concentrated in recording the tissue surface of the defect, which made it difficult to contour the palpebral surface resulting in the poor esthetics of the prosthesis. The present impression technique uses heavy bodied polyvinyl siloxane impression material, which facilitates accurate recording of the tissue surface and the palpebral surface of the defect, resulting in the fabrication of functionally and esthetically acceptable prosthesis. PMID:26265651

  1. Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties.

    PubMed

    Kuo, Chin-Guo; Chang, Ho; Wang, Jian-Hao

    2016-01-01

    In this investigation, anodic aluminum oxide (AAO) with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn) into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO) nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 μm, 60 μm, and 70 μm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA. PMID:27023546

  2. Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties

    PubMed Central

    Kuo, Chin-Guo; Chang, Ho; Wang, Jian-Hao

    2016-01-01

    In this investigation, anodic aluminum oxide (AAO) with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn) into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO) nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 μm, 60 μm, and 70 μm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA. PMID:27023546

  3. Application of Optical Measurement Techniques During Fabrication and Testing of Liquid Rocket Nozzles

    NASA Technical Reports Server (NTRS)

    Gradl, Paul R.

    2015-01-01

    This paper presents a series of optical measurement techniques that were developed for use during large-scale fabrication and testing of nozzle components. A thorough understanding of hardware throughout the fabrication cycle and hotfire testing is critical to meet component design intent. Regeneratively cooled nozzles and associated tooling require tight control of tolerances during the fabrication process to ensure optimal performance. Additionally, changes in geometry during testing can affect performance of the nozzle and mating components. Structured light scanning and digital image correlation techniques were used to collect data during the fabrication and test of nozzles, in addition to other engine components. This data was used to analyze deformations data during machining, heat treatment, assembly and testing operations. A series of feasibility experiments were conducted for these techniques that led to use on full scale nozzles during the J-2X upper stage engine program in addition to other engine development programs. This paper discusses the methods and results of these measurement techniques throughout the nozzle life cycle and application to other components.

  4. Enzyme-etching technique to fabricate micropatterns of aligned collagen fibrils

    PubMed Central

    Liu, Honghai; Chen, Ruikai; Yang, Huaxiao; Qin, Wan; Borg, Thomas K.; Dean, Delphine; Xu, Meifeng; Gao, Bruce Z.

    2014-01-01

    A technique to tailor-make pre-coated, pre-aligned bovine collagen fibrils, derived from neonatal cardiomyocytes, on the surface of a glass slide into a designated pattern is reported. The unwanted collagen-coated area was erased by a collagenase solution and the tailored area was retained by attaching a microfabricated polydimethylsiloxane stamp directly to the collagen-coated surface. Using this technique, collagen patterns with designated orientations and with clear pattern boundaries and defined shapes were fabricated. PMID:24562408

  5. Multimodal optogenetic neural interfacing device fabricated by scalable optical fiber drawing technique.

    PubMed

    Davey, Christopher J; Argyros, Alexander; Fleming, Simon C; Solomon, Samuel G

    2015-12-01

    We present a novel approach to the design and manufacture of optrodes for use in the biomedical research field of optogenetic neural interfacing. Using recently developed optical fiber drawing techniques that involve co-drawing metal/polymer composite fiber, we have assembled and characterized a novel optrode with promising optical and electrical functionality. The fabrication technique is flexible, scalable, and amenable to extension to implantable optrodes with high-density arrays of multiple electrodes, waveguides, and drug delivery channels. PMID:26836662

  6. A technique to orient a stone cast in the fabrication of a nasal prosthesis.

    PubMed

    Acharya, Varun; Montgomery, Patricia C

    2014-09-01

    Obtaining the correct orientation of the stone cast in the fabrication of a nasal prosthesis is a challenging task. The current technique involves repeated trials of the waxed nasal prosthesis on the patient's face to establish its correct position. This article proposes a simplified technique to aid in establishing the proper orientation of the stone cast in an effort to decrease the number of error corrections related to midline discrepancies during the wax sculpting stage. PMID:24725614

  7. Fabrication of Ultrasensitive Field-Effect Transistor DNA Biosensors by a Directional Transfer Technique Based on CVD-Grown Graphene.

    PubMed

    Zheng, Chao; Huang, Le; Zhang, Hong; Sun, Zhongyue; Zhang, Zhiyong; Zhang, Guo-Jun

    2015-08-12

    Most graphene field-effect transistor (G-FET) biosensors are fabricated through a routine process, in which graphene is transferred onto a Si/SiO2 substrate and then devices are subsequently produced by micromanufacture processes. However, such a fabrication approach can introduce contamination onto the graphene surface during the lithographic process, resulting in interference for the subsequent biosensing. In this work, we have developed a novel directional transfer technique to fabricate G-FET biosensors based on chemical-vapor-deposition- (CVD-) grown single-layer graphene (SLG) and applied this biosensor for the sensitive detection of DNA. A FET device with six individual array sensors was first fabricated, and SLG obtained by the CVD-growth method was transferred onto the sensor surface in a directional manner. Afterward, peptide nucleic acid (PNA) was covalently immobilized on the graphene surface, and DNA detection was realized by applying specific target DNA to the PNA-functionalized G-FET biosensor. The developed G-FET biosensor was able to detect target DNA at concentrations as low as 10 fM, which is 1 order of magnitude lower than those reported in a previous work. In addition, the biosensor was capable of distinguishing the complementary DNA from one-base-mismatched DNA and noncomplementary DNA. The directional transfer technique for the fabrication of G-FET biosensors is simple, and the as-constructed G-FET DNA biosensor shows ultrasensitivity and high specificity, indicating its potential application in disease diagnostics as a point-of-care tool. PMID:26203889

  8. Fabrication of single domain GdBCO bulk superconductors by a new modified TSIG technique

    NASA Astrophysics Data System (ADS)

    Yang, W. M.; Zhi, X.; Chen, S. L.; Wang, M.; Li, J. W.; Ma, J.; Chao, X. X.

    2014-01-01

    Single domain GdBCO bulk superconductors have been fabricated with new and traditional solid phases by a top seeded infiltration and growth (TSIG) process technique. In the conventional TSIG process, three types of powders, such as Gd2BaCuO5, GdBa2Cu3O7-x and Ba3Cu5O8, must be prepared, but in our new modified TSIG technique, only BaCuO2 powders are required during the fabrication of the single domain GdBCO bulk superconductors. The solid phase used in the conventional process is Gd2BaCuO5 instead of the solid phase (Gd2O3 + BaCuO2) utilized in the new process. The liquid phase used in the conventional process is a mixture of (GdBa2Cu3O7-x + Ba3Cu5O8), and the liquid phase in the new process is a mixture of (Gd2O3 + 10BaCuO2 + 6CuO). Single domain GdBCO bulk superconductors have been fabricated with the new solid and liquid phases. The levitation force of the GdBCO bulk samples fabricated by the new solid phase is 28 N, which is slightly higher than that of the samples fabricated using the conventional solid phases (26 N). The microstructure and the levitation force of the samples indicate that this new method can greatly simplify the fabrication process, introduce nanometer-sized flux centers, improve the levitation force and working efficiency, and greatly reduce the cost of fabrication of single domain GdBCO bulk superconductors by the TSIG process.

  9. Nacre-like materials using a simple doctor blading technique: Fabrication, testing and modeling.

    PubMed

    Mirkhalaf, M; Barthelat, F

    2016-03-01

    The remarkable mechanical performance of biological materials such as bone, nacre, and spider silk stems from their staggered microstructure in which stiff and strong reinforcements are elongated in the direction of loading, separated by softer interfaces, and shifted relative to each other. This structure results in useful combinations of modulus, strength and toughness and therefore is increasingly mimicked in bio-inspired engineering composites. Here, we report the use of a simple and versatile technique based on doctor-blading to fabricate staggered composites of microscopic alumina tablets with high alignment in a chitosan matrix. Tensile tests on these nacre-like materials show that the modulus and strength of the composite films are enhanced by the incorporation of ceramic tablets, but only up to 15vol% after which all properties degrade. This phenomenon, also reported in the past for most of nacre-like materials, composed of micro/nano tablets, obtained from different techniques, has been limiting our ability to produce large volumes of high-performance nacre-like materials. Examination of the structure of the films revealed that at lower tablet concentrations the tablets are well-aligned and well dispersed thorough the volume of the film. At 15vol% and beyond, we observed tablet misalignment and clustering. In order to investigate the impact of these imperfections on material performance we developed large scale finite element models representative of the structure of the composite films. These models show that the mechanical performance significantly degrades with tablet misalignment, and especially at high tablet concentrations. The simulations along with the SEM images therefore quantitatively explain the experimental trends, e.g. the degradation of mechanical properties at high tablet contents. PMID:26655459

  10. Er3+-activated photonic structures fabricated by sol-gel and rf-sputtering techniques

    NASA Astrophysics Data System (ADS)

    Ferrari, M.; Alombert-Goget, G.; Armellini, C.; Berneschi, S.; Bhaktha, S. N. B.; Boulard, B.; Brenci, M.; Chiappini, A.; Chiasera, A.; Duverger-Arfuso, C.; Féron, P.; Gonçalves, R. R.; Jestin, Y.; Minati, L.; Moser, E.; Nunzi Conti, G.; Pelli, S.; Rao, D. N.; Retoux, R.; Righini, G. C.; Speranza, G.

    2009-05-01

    The realization of photonic structures operating at visible and near infrared frequencies is a highly attractive scientific and technological challenge. Since optical fiber innovation, a huge of activity has been performed leading to interesting results, such as optical waveguides and planar lightwave circuits, microphotonic devices, optical microcavities, nanowires, plasmonic structures, and photonic crystals. These systems have opened new possibilities in the field of both basic and applied physics, in a large area covering Information Communication Technologies, Health and Biology, Structural Engineering, and Environment Monitoring Systems. Several materials and techniques are employed to successfully fabricate photonic structures. Concerning materials, Er3+-activated silica-based glasses still play an important role, although recently interesting results have been published about fluoride glass-ceramic waveguides. As far as regards the fabrication methods sol-gel route and rf sputtering have proved to be versatile and reliable techniques. In this article we will present a review of some Er3+-activated photonic structures fabricated by sol gel route and rf sputtering deposition. In the discussion on the sol-gel approach we focus our attention on the silica-hafnia binary system presenting an overview concerning fabrication protocols and structural, optical and spectroscopic assessment of SiO2-HfO2 waveguides activated by Er3+ ions. In order to put in evidence the reliability and versatility of the sol-gel route for photonics applications four different confined structures are briefly presented: amorphous waveguides, coated microspheres, monolithic waveguide laser, and core-shell nanospheres. As examples of rf sputtering technique, we will discuss Er3+-activated silica-hafnia and silica-germania waveguides, the latter system allowing fabrication of integrated optics structures by UV photo-imprinting. Finally, two examples of photonic crystal structures, one

  11. Fabrication of enzyme-degradable and size-controlled protein nanowires using single particle nano-fabrication technique

    NASA Astrophysics Data System (ADS)

    Omichi, Masaaki; Asano, Atsushi; Tsukuda, Satoshi; Takano, Katsuyoshi; Sugimoto, Masaki; Saeki, Akinori; Sakamaki, Daisuke; Onoda, Akira; Hayashi, Takashi; Seki, Shu

    2014-04-01

    Protein nanowires exhibiting specific biological activities hold promise for interacting with living cells and controlling and predicting biological responses such as apoptosis, endocytosis and cell adhesion. Here we report the result of the interaction of a single high-energy charged particle with protein molecules, giving size-controlled protein nanowires with an ultra-high aspect ratio of over 1,000. Degradation of the human serum albumin nanowires was examined using trypsin. The biotinylated human serum albumin nanowires bound avidin, demonstrating the high affinity of the nanowires. Human serum albumin-avidin hybrid nanowires were also fabricated from a solid state mixture and exhibited good mechanical strength in phosphate-buffered saline. The biotinylated human serum albumin nanowires can be transformed into nanowires exhibiting a biological function such as avidin-biotinyl interactions and peroxidase activity. The present technique is a versatile platform for functionalizing the surface of any protein molecule with an extremely large surface area.

  12. High T(sub c) superconductors fabricated by plasma aerosol mist deposition technique

    NASA Technical Reports Server (NTRS)

    Wang, X. W.; Vuong, K. D.; Leone, A.; Shen, C. Q.; Williams, J.; Coy, M.

    1995-01-01

    We report new results on high T(sub c) superconductors fabricated by a plasma aerosol mist deposition technique, in atmospheric environment. Materials fabricated are YBaCuO, BiPbSrCaCuO, BaCaCuO precursor films for TlBaCaCuO, and other buffers such as YSZ. Depending on processing conditions, sizes of crystallites and/or particles are between dozens of nano-meters and several micrometers. Superconductive properties and other material characteristics can also be tailored.

  13. Construction of cardiac tissue rings using a magnetic tissue fabrication technique.

    PubMed

    Akiyama, Hirokazu; Ito, Akira; Sato, Masanori; Kawabe, Yoshinori; Kamihira, Masamichi

    2010-01-01

    Here we applied a magnetic force-based tissue engineering technique to cardiac tissue fabrication. A mixture of extracellular matrix precursor and cardiomyocytes labeled with magnetic nanoparticles was added into a well containing a central polycarbonate cylinder. With the use of a magnet, the cells were attracted to the bottom of the well and allowed to form a cell layer. During cultivation, the cell layer shrank towards the cylinder, leading to the formation of a ring-shaped tissue that possessed a multilayered cell structure and contractile properties. These results indicate that magnetic tissue fabrication is a promising approach for cardiac tissue engineering. PMID:21152282

  14. Microforging technique for rapid, low-cost fabrication of lens array molds.

    PubMed

    Forest, Craig R; Saez, Miguel A; Hunter, Ian W

    2007-12-20

    Interest in micro-optical components for applications ranging from telecommunications to life sciences has driven the need for accessible, low-cost fabrication techniques. Many microlens fabrication processes are unsuitable for applications requiring 100% fill factor, apertures approximately 1000 microm with high numerical aperture, and scalability to large areas (e.g., tens of centimeters to meters) with millions of lenses. We report on a flexible, low-cost mold fabrication technique that utilizes a combination of milling and microforging. The technique involves first performing a rough cut with a ball-end mill. Final shape and sag height are then achieved by pressing a sphere of equal diameter into the milled divot. Using this process, we have fabricated molds for rectangular arrays of 1-10,000 lenses with apertures of 25-1600 microm, sag heights of 3-130 microm, interlens spacings of 250-2000 microm, and fill factors up to 100%. Mold profiles have a roughness and figure error of 68 nm and 354 nm, respectively, for 100% fill factor, 1000 microm aperture lenses. The required forging force was modeled as a modified open-die forging process and experimentally verified to increase nearly linearly with surface area. The optical performance of lens arrays injection molded from microforged molds was characterized by imaging the point spread function and was found to be in the range of theoretical values. The process can be easily adapted to lenticular arrays as well. Limitations include milling machine range and accuracy. PMID:18091978

  15. Instantly AgNPs deposition through facile solventless technique for poly-functional cotton fabrics.

    PubMed

    Emam, Hossam E; Saleh, N H; Nagy, Khaled S; Zahran, M K

    2016-03-01

    Nowadays, functional clothes are employed for human body protection in addition to be fashionable clothes. Hence functionalization of clothes increases the attention of scientists and business. In the current study, poly-functional cotton fabric was carried out by instantly deposition of AgNPs using two solventless techniques namely; sorption and padding. Sorption technique was exhibited extremely high efficiency than padding one by ca. 10 times. By using the same concentrations of AgNO3, Ag content was ranged 69.3-6094.8 mg/kg and 33.8-609.3 mg/kg for sorption and padding, respectively. After AgNPs deposition, fabrics color was turned to gray-reddish yellow. By applying 5912.3 mgAg/kg fabric, bacterial reduction and UPF value were reached 99% and 12.59. Bacterial reduction and UPF were lessened to 90% and 10.19 after 20 washings. These findings proved that the direct AgNPs deposition into cotton using solventless/sorption technique is applicable in manufacturing of antibacterial/UV resistant fabrics with acquired decorative color. PMID:26708429

  16. Fabrication of matrix-addressable micro-LED arrays based on a novel etch technique

    NASA Astrophysics Data System (ADS)

    Choi, H. W.; Jeon, C. W.; Dawson, M. D.

    2004-08-01

    A novel method of etching which allows the direct interconnection of multiple GaN-based devices is introduced. The mesa structures of devices are etched using an isotropic recipe which produces tapered sidewalls. The extent of inclination can be readily controlled through various etching parameters, which include the ICP power, plate power and pressure, thus modifying the vertical and lateral etch components. This approach has been successfully adopted in the fabrication of interconnect and matrix-addressable micro-LEDs, which offer superior optical and electrical performance and a high degree of uniformity compared to similar devices fabricated using conventional processes.

  17. X-ray phase imaging using a Gd-based absorption grating fabricated by imprinting technique

    NASA Astrophysics Data System (ADS)

    Yashiro, Wataru; Kato, Kosuke; Sadeghilaridjani, Maryam; Momose, Atsushi; Shinohara, Takenao; Kato, Hidemi

    2016-04-01

    A high-aspect-ratio absorption grating with a pitch of several µm is a key component of X-ray grating interferometery, which is an X-ray phase imaging technique that allows for highly sensitive X-ray imaging with a compact laboratory X-ray source. Here, we report that X-ray phase imaging was successfully performed at 15 keV by using a 23 ± 1-µm-height, 9-µm-pitch absorption grating (10 × 10 mm2) based on Gd (Gd60Cu25Al15) fabricated by a metallic glass imprinting technique. The imprinting technique is cost-efficient and has a high-production rate, and will be widely used for fabricating gratings not only for X-rays but also neutrons in the near future.

  18. Electroless-plating technique for fabricating thin-wall convective heat-transfer models

    NASA Technical Reports Server (NTRS)

    Avery, D. E.; Ballard, G. K.; Wilson, M. L.

    1984-01-01

    A technique for fabricating uniform thin-wall metallic heat-transfer models and which simulates a Shuttle thermal protection system tile is described. Two 6- by 6- by 2.5-in. tiles were fabricated to obtain local heat transfer rates. The fabrication process is not limited to any particular geometry and results in a seamless thin-wall heat-transfer model which uses a one-wire thermocouple to obtain local cold-wall heat-transfer rates. The tile is relatively fragile because of the brittle nature of the material and the structural weakness of the flat-sided configuration; however, a method was developed and used for repairing a cracked tile.

  19. Application of Anisotropic Conductive Film to Fabrication of Molybdenum Field Emitter Arrays Using Transfer Mold Technique

    NASA Astrophysics Data System (ADS)

    Cho, Eou Sik; Ahn, Min Hyung; Kwon, Sang Jik

    2008-08-01

    In the fabrication of molybdenum field emitter arrays (Mo FEA) by the transfer mold technique, anisotropic conductive film (ACF) was applied to the bond between the inverted mold structure and the transferred glass substrate. Without any electrical treatment of electrostatic bonding, the inverted mold was successfully bonded to an indium tin oxide (ITO) glass substrate under optimized thermal and pressure conditions. No additional conductive layers were used in the bonding process, and the bonded ACF was not chemically affected in the wet-etch process of the silicon inverted mold structure. The fabricated Mo FEA was structurally and electrically investigated and an anode current of 10 nA per emitter was obtained at a gate bias of 94 V. The results demonstrate the possibility of selective conduction in the fabrication of transfer mold FEA using ACF bonding.

  20. Investigation of etching techniques for superconductive Nb/Al-Al2O3/Nb fabrication processes

    NASA Technical Reports Server (NTRS)

    Lichtenberger, A. W.; Lea, D. M.; Lloyd, F. L.

    1993-01-01

    Wet etching, CF4 and SF6 reactive ion etching (RIE), RIE/wet hybrid etching, Cl-based RIE, ion milling, and liftoff techniques have been investigated for use in superconductive Nb/Al-Al2O3/Nb fabrication processes. High-quality superconductor-insulator-superconductor (SIS) junctions have been fabricated using a variety of these etching methods; however, each technique offers distinct tradeoffs for a given process an wafer design. In particular, it was shown that SF6 provides an excellent RIE chemistry for low-voltage anisotropic etching of Nb with high selectivity to Al. The SF6 tool has greatly improved the trilevel resist junction insulation process. Excellent repeatability, selectivity with respect to quartz, and submicron resolution make Cl2 + BCl3 + CHCl3 RIE a very attractive process for trilayer patterning.

  1. Fabrication of advanced electrochemical energy materials using sol-gel processing techniques

    NASA Technical Reports Server (NTRS)

    Chu, C. T.; Chu, Jay; Zheng, Haixing

    1995-01-01

    Advanced materials play an important role in electrochemical energy devices such as batteries, fuel cells, and electrochemical capacitors. They are being used as both electrodes and electrolytes. Sol-gel processing is a versatile solution technique used in fabrication of ceramic materials with tailored stoichiometry, microstructure, and properties. The application of sol-gel processing in the fabrication of advanced electrochemical energy materials will be presented. The potentials of sol-gel derived materials for electrochemical energy applications will be discussed along with some examples of successful applications. Sol-gel derived metal oxide electrode materials such as V2O5 cathodes have been demonstrated in solid-slate thin film batteries; solid electrolytes materials such as beta-alumina for advanced secondary batteries had been prepared by the sol-gel technique long time ago; and high surface area transition metal compounds for capacitive energy storage applications can also be synthesized with this method.

  2. Fabrication of Porous Copper with Directional Pores by Continuous Casting Technique Through Thermal Decomposition of Hydride

    NASA Astrophysics Data System (ADS)

    Ide, Takuya; Tsunemi, Akihiro; Nakajima, Hideo

    2014-08-01

    Lotus-type porous copper with aligned long cylindrical pores was fabricated by continuous casting technique through thermal decomposition method (TDM) in an argon atmosphere of 0.1 MPa. A pellet of titanium hydride was supplied into molten copper with adjusting the time interval to maintain the constant concentration of hydrogen to be dissolved in the melt, when the transfer velocity of the unidirectional solidification is changed. Long lotus-type porous copper slabs were fabricated with constant solidification velocity. The effect of the transfer velocity on the porosity and pore size was investigated. The average pore diameter was independent of the transfer velocity, but the porosity is slightly dependent on the velocity. It is apparent that the continuous casting technique can be applicable for production of lotus metals through TDM.

  3. Antimicrobial Activity of Ultra-fine Fiber Nonwoven Fabrics Produced by Electrospinning

    NASA Astrophysics Data System (ADS)

    Ogushi, Yukiko; Sasaki, Naokazu; Imashiro, Yasuo; Minagawa, Mie; Matsumoto, Hidetoshi; Tanioka, Akihiko

    Electrospinning is based on an electrohydrodynamic process, and it is a straightforward and versatile method for forming continuous thin fibers from several nanometers to several tens of micrometers in diameter. One major advantage of electrospinning is the one-step forming of nonwoven fibrous fabrics. In the present study, we prepared ultra-fine fiber nonwoven fabrics from 13 kinds of commercial polymers (e.g., PLA, PA, PU, Cellulose, PVDC, and PS) by electrospinning and tested their antimicrobial activity. Most of ultra-fine fiber nonwoven fabrics showed excellent antimicrobial activity. Our experimental results showed that there is close correlation between fiber diameter of nonwoven fabrics and their antimicrobial activity: the nonwoven fabrics with average fiber diameter of smaller than 800 nm showed better antimicrobial activity.

  4. Fabrication of multiferroic GdMnO3 thin film by pulsed laser deposition technique

    NASA Astrophysics Data System (ADS)

    Negi, Puneet; Agrawal, H. M.; Srivastava, R. C.; Asokan, K.

    2012-06-01

    Here, we report the fabrication of GdMnO3 multiferroic thin film on SrTiO3 (110) substrate by pulsed laser deposition (PLD) technique. The target sample was synthesized using modified solgel route. The thickness of the film observed by Talystep profilometer, is about 200 nm. X-ray diffraction and Raman spectroscopic techniques were used to investigate the structure of the target as well as of the film. The surface topography of the film was investigated by atomic force microscopy.

  5. Simple reflow technique for fabrication of a microlens array in solgel glass.

    PubMed

    He, M; Yuan, X C; Ngo, N Q; Bu, J; Kudryashov, V

    2003-05-01

    A simple reflow method for fabrication of refractive microlens arrays in inorganic-organic SiO2-ZrO2 solgel glass is presented. To our knowledge, this is the first report that presents a simple reflow technique for transforming a negatively induced hybrid solgel material into desirable spherical microlenses. It is shown that the microlenses have excellent smooth surfaces and uniform dimensions. The reflow technique is considerably cheaper than use of a high-energy beam-sensitive gray-scale mask and is suitable for mass production. PMID:12747722

  6. Analytical and experimental evaluation of techniques for the fabrication of thermoplastic hologram storage devices

    NASA Technical Reports Server (NTRS)

    Rogers, J. W.

    1975-01-01

    The results of an experimental investigation on recording information on thermoplastic are given. A description was given of a typical fabrication configuration, the recording sequence, and the samples which were examined. There are basically three configurations which can be used for the recording of information on thermoplastic. The most popular technique uses corona which furnishes free charge. The necessary energy for deformation is derived from a charge layer atop the thermoplastic. The other two techniques simply use a dc potential in place of the corona for deformation energy.

  7. Microstructural Examination to Aid in Understanding Friction Bonding Fabrication Technique for Monolithic Nuclear Fuel

    SciTech Connect

    Karen L. Shropshire

    2008-04-01

    Monolithic nuclear fuel is currently being developed for use in research reactors, and friction bonding (FB) is a technique being developed to help in this fuel’s fabrication. Since both FB and monolithic fuel are new concepts, research is needed to understand the impact of varying FB fabrication parameters on fuel plate characteristics. This thesis research provides insight into the FB process and its application to the monolithic fuel design by recognizing and understanding the microstructural effects of varying fabrication parameters (a) FB tool load, and (b) FB tool face alloy. These two fabrication parameters help drive material temperature during fabrication, and thus the material properties, bond strength, and possible formation of interface reaction layers. This study analyzed temperatures and tool loads measured during those FB processes and examined microstructural characteristics of materials and bonds in samples taken from the resulting fuel plates. This study shows that higher tool load increases aluminum plasticization and forging during FB, and that the tool face alloy helps determine the tool’s heat extraction efficacy. The study concludes that successful aluminum bonds can be attained in fuel plates using a wide range of FB tool loads. The range of tool loads yielding successful uranium-aluminum bonding was not established, but it was demonstrated that such bonding can be attained with FB tool load of 48,900 N (11,000 lbf) when using a FB tool faced with a tungsten alloy. This tool successfully performed FB, and with better results than tools faced with other materials. Results of this study correlate well with results reported for similar aluminum bonding techniques. This study’s results also provide support and validation for other nuclear fuel development studies and conclusions. Recommendations are offered for further research.

  8. Fabrication of a flat V3+/Fe3+ redox microbattery from gold compact disk using drilling technique

    NASA Astrophysics Data System (ADS)

    Hantezadeh, Mehri; Rashid-Nadimi, Sahar

    2016-02-01

    Here a simple design which could be developed for flat redox microbattery array with tunable output power is introduced. The fabrication of a V3+/Fe3+ redox microbattery using the gold compact disk (CD) as the electrode material and employing drilling technique to fabricate band electrodes is reported. The as-fabricated V3+/Fe3+ redox microbattery shows very attractive performance such as rechargeability, very high power and current density, low cost and simplicity of fabrication. Also microbattery arrays could be stacked very easily to achieve proper voltage, current and output power. Polarization and power curves and charge-discharge cycles are obtained to characterize as-fabricated microbatteries.

  9. Review of high-throughput techniques for detecting solid phase Transformation from material libraries produced by combinatorial methods

    NASA Technical Reports Server (NTRS)

    Lee, Jonathan A.

    2005-01-01

    High-throughput measurement techniques are reviewed for solid phase transformation from materials produced by combinatorial methods, which are highly efficient concepts to fabricate large variety of material libraries with different compositional gradients on a single wafer. Combinatorial methods hold high potential for reducing the time and costs associated with the development of new materials, as compared to time-consuming and labor-intensive conventional methods that test large batches of material, one- composition at a time. These high-throughput techniques can be automated to rapidly capture and analyze data, using the entire material library on a single wafer, thereby accelerating the pace of materials discovery and knowledge generation for solid phase transformations. The review covers experimental techniques that are applicable to inorganic materials such as shape memory alloys, graded materials, metal hydrides, ferric materials, semiconductors and industrial alloys.

  10. Antimicrobial fabric adsorbed iodine produced by radiation-induced graft polymerization

    NASA Astrophysics Data System (ADS)

    Aoki, Shoji; Fujiwara, Kunio; Sugo, Takanobu; Suzuki, Koichi

    2013-03-01

    Antimicrobial fabric was synthesized by radiation-induced graft polymerization of N-vinyl pyrrolidone onto polyolefine nonwoven fabric and subsequent adsorption of iodine. In response of the huge request for the antimicrobial material applied to face masks for swine flu in 2009, operation procedure of continuous radiation-induced graft polymerization apparatus was improved. The improved grafting production per week increased 3.8 times compared to the production by former operation procedure. Shipped antimicrobial fabric had reached 130,000 m2 from June until December, 2009.

  11. A review of computer-aided design/computer-aided manufacture techniques for removable denture fabrication

    PubMed Central

    Bilgin, Mehmet Selim; Baytaroğlu, Ebru Nur; Erdem, Ali; Dilber, Erhan

    2016-01-01

    The aim of this review was to investigate usage of computer-aided design/computer-aided manufacture (CAD/CAM) such as milling and rapid prototyping (RP) technologies for removable denture fabrication. An electronic search was conducted in the PubMed/MEDLINE, ScienceDirect, Google Scholar, and Web of Science databases. Databases were searched from 1987 to 2014. The search was performed using a variety of keywords including CAD/CAM, complete/partial dentures, RP, rapid manufacturing, digitally designed, milled, computerized, and machined. The identified developments (in chronological order), techniques, advantages, and disadvantages of CAD/CAM and RP for removable denture fabrication are summarized. Using a variety of keywords and aiming to find the topic, 78 publications were initially searched. For the main topic, the abstract of these 78 articles were scanned, and 52 publications were selected for reading in detail. Full-text of these articles was gained and searched in detail. Totally, 40 articles that discussed the techniques, advantages, and disadvantages of CAD/CAM and RP for removable denture fabrication and the articles were incorporated in this review. Totally, 16 of the papers summarized in the table. Following review of all relevant publications, it can be concluded that current innovations and technological developments of CAD/CAM and RP allow the digitally planning and manufacturing of removable dentures from start to finish. As a result according to the literature review CAD/CAM techniques and supportive maxillomandibular relationship transfer devices are growing fast. In the close future, fabricating removable dentures will become medical informatics instead of needing a technical staff and procedures. However the methods have several limitations for now. PMID:27095912

  12. A review of computer-aided design/computer-aided manufacture techniques for removable denture fabrication.

    PubMed

    Bilgin, Mehmet Selim; Baytaroğlu, Ebru Nur; Erdem, Ali; Dilber, Erhan

    2016-01-01

    The aim of this review was to investigate usage of computer-aided design/computer-aided manufacture (CAD/CAM) such as milling and rapid prototyping (RP) technologies for removable denture fabrication. An electronic search was conducted in the PubMed/MEDLINE, ScienceDirect, Google Scholar, and Web of Science databases. Databases were searched from 1987 to 2014. The search was performed using a variety of keywords including CAD/CAM, complete/partial dentures, RP, rapid manufacturing, digitally designed, milled, computerized, and machined. The identified developments (in chronological order), techniques, advantages, and disadvantages of CAD/CAM and RP for removable denture fabrication are summarized. Using a variety of keywords and aiming to find the topic, 78 publications were initially searched. For the main topic, the abstract of these 78 articles were scanned, and 52 publications were selected for reading in detail. Full-text of these articles was gained and searched in detail. Totally, 40 articles that discussed the techniques, advantages, and disadvantages of CAD/CAM and RP for removable denture fabrication and the articles were incorporated in this review. Totally, 16 of the papers summarized in the table. Following review of all relevant publications, it can be concluded that current innovations and technological developments of CAD/CAM and RP allow the digitally planning and manufacturing of removable dentures from start to finish. As a result according to the literature review CAD/CAM techniques and supportive maxillomandibular relationship transfer devices are growing fast. In the close future, fabricating removable dentures will become medical informatics instead of needing a technical staff and procedures. However the methods have several limitations for now. PMID:27095912

  13. Communication methods and production techniques in fixed prosthesis fabrication: a UK based survey. Part 2: Production techniques

    PubMed Central

    Berry, J.; Nesbit, M.; Saberi, S.; Petridis, H.

    2014-01-01

    Aim The aim of this study was to identify the communication methods and production techniques used by dentists and dental technicians for the fabrication of fixed prostheses within the UK from the dental technicians' perspective. This second paper reports on the production techniques utilised. Materials and methods Seven hundred and eighty-two online questionnaires were distributed to the Dental Laboratories Association membership and included a broad range of topics, such as demographics, impression disinfection and suitability, and various production techniques. Settings were managed in order to ensure anonymity of respondents. Statistical analysis was undertaken to test the influence of various demographic variables such as the source of information, the location, and the size of the dental laboratory. Results The number of completed responses totalled 248 (32% response rate). Ninety percent of the respondents were based in England and the majority of dental laboratories were categorised as small sized (working with up to 25 dentists). Concerns were raised regarding inadequate disinfection protocols between dentists and dental laboratories and the poor quality of master impressions. Full arch plastic trays were the most popular impression tray used by dentists in the fabrication of crowns (61%) and bridgework (68%). The majority (89%) of jaw registration records were considered inaccurate. Forty-four percent of dental laboratories preferred using semi-adjustable articulators. Axial and occlusal under-preparation of abutment teeth was reported as an issue in about 25% of cases. Base metal alloy was the most (52%) commonly used alloy material. Metal-ceramic crowns were the most popular choice for anterior (69%) and posterior (70%) cases. The various factors considered did not have any statistically significant effect on the answers provided. The only notable exception was the fact that more methods of communicating the size and shape of crowns were utilised for

  14. Fabrication of Converging and Diverging Polymeric Microlens Arrays By A Thermocapillary Replication Technique

    NASA Astrophysics Data System (ADS)

    Lim, Soon Wei Daniel; Fiedler, Kevin; Troian, Sandra

    Thermocapillary forces offer a powerful method for sculpting interfaces at microscale dimensions. Here we demonstrate how periodic arrays of cooled pins placed in close proximity to the surface of a molten polymer nanofilm can be used to fabricate various large area microlens arrays, which when solidified exhibit ultrasmooth surfaces and excellent focusing capability. This technique was used to fabricate both homogeneous converging and diverging microlens shapes by application of various thermal distributions. The converging arrays were incorporated into a Shack-Hartmann wavefront sensor able to image moving currents of airborne spray droplets. Feature overlap was also used to achieve hierarchical arrays comprising two superimposed patterns. By varying the width of the cooled pins, it was also possible to fabricate converging microlens structures featuring a caldera-like depression at the vertex able to focus collimated light into a sharp annulus. These demonstrations prove that with suitable microscale control over the thermal distributions projected onto molten nanofilms, a diverse set of micro-optical components can be fabricated by thermocapillary replication from a nearby mask without contact and in a single step. S. W. D. Lim acknowledges funding from the Toshi Kubota SURF fellowship. KRF is supported by a NASA Science and Technology Research Fellowship.

  15. Fabrication of dielectrophoretic microfluidic chips using a facile screen-printing technique for microparticle trapping

    NASA Astrophysics Data System (ADS)

    Wee, Wei Hong; Li, Zedong; Hu, Jie; Adib Kadri, Nahrizul; Xu, Feng; Li, Fei; Pingguan-Murphy, Belinda

    2015-10-01

    Trapping of microparticles finds wide applications in numerous fields. Microfluidic chips based on a dielectrophoresis (DEP) technique hold several advantages for trapping microparticles, such as fast result processing, a small amount of sample required, high spatial resolution, and high accuracy of target selection. There is an unmet need to develop DEP microfluidic chips on different substrates for different applications in a low cost, facile, and rapid way. This study develops a new facile method based on a screen-printing technique for fabrication of electrodes of DEP chips on three types of substrates (i.e. polymethyl-methacrylate (PMMA), poly(ethylene terephthalate) and A4 paper). The fabricated PMMA-based DEP microfluidic chip was selected as an example and successfully used to trap and align polystyrene microparticles in a suspension and cardiac fibroblasts in a cell culture solution. The developed electrode fabrication method is compatible with different kinds of DEP substrates, which could expand the future application field of DEP microfluidic chips, including new forms of point-of care diagnostics and trapping circulating tumor cells.

  16. Surface properties and corrosion behavior of Co-Cr alloy fabricated with selective laser melting technique.

    PubMed

    Xin, Xian-zhen; Chen, Jie; Xiang, Nan; Wei, Bin

    2013-01-01

    We sought to study the corrosion behavior and surface properties of a commercial cobalt-chromium (Co-Cr) alloy which was fabricated with selective laser melting (SLM) technique. For this purpose, specimens were fabricated using different techniques, such as SLM system and casting methods. Surface hardness testing, microstructure observation, surface analysis using X-ray photoelectron spectroscopy (XPS) and electrochemical corrosion test were carried out to evaluate the corrosion properties and surface properties of the specimens. We found that microstructure of SLM specimens was more homogeneous than that of cast specimens. The mean surface hardness values of SLM and cast specimens were 458.3 and 384.8, respectively; SLM specimens showed higher values than cast ones in hardness. Both specimens exhibited no differences in their electrochemical corrosion properties in the artificial saliva through potentiodynamic curves and EIS, and no significant difference via XPS. Therefore, we concluded that within the scope of this study, SLM-fabricated restorations revealed good surface properties, such as proper hardness, homogeneous microstructure, and also showed sufficient corrosion resistance which could meet the needs of dental clinics. PMID:23553145

  17. Evaluation of Dielectric Properties of Ferroelectric Fine Particles Fabricated by Focused Ion Beam Technique

    NASA Astrophysics Data System (ADS)

    Ogiso, Hisato; Yoshida, Mikiko; Akedo, Jun

    2007-10-01

    In this study, we propose a method for evaluating the dielectric property of a single fine particle using the focused ion beam technieque. Lead zirconate titanate (PZT) particles (Sakai Chemical Industry LQ) were sintered at 1473 K for 2 h to fabricate bulk PZT. The bulk PZT was milled to fabricate sample particles. The particles were dispersed on a Au surface substrate, and were shaped into a parallel-plate capacitor using the focused ion beam (FIB) technique. The FIB technique was used to deposite tungsten, W, with a square shape on top of the particle sample as an upper electrode, and the particles were shaved into a rectangular shape; the area of the electrode was 2× 10-12 m2 and the thickness of the PZT segment was 2× 10-6 m. The capacitance of the fabricated PZT particle sample was successfully measured by compensating the parasitic capacitance of the experimental setup. Consequently, the relative permittivity of the PZT particle sample was 1250 at 105 Hz. This value was comparably close to the 1750 of the bulk PZT. The issue of electric contact between the particles and the substrate should be overcome in order to discuss permittivity quantitatively.

  18. Fabrication of superconducting MgB2 nanostructures by an electron beam lithography-based technique

    NASA Astrophysics Data System (ADS)

    Portesi, C.; Borini, S.; Amato, G.; Monticone, E.

    2006-03-01

    In this work, we present the results obtained in fabrication and characterization of magnesium diboride nanowires realized by an electron beam lithography (EBL)-based method. For fabricating MgB2 thin films, an all in situ technique has been used, based on the coevaporation of B and Mg by means of an e-gun and a resistive heater, respectively. Since the high temperatures required for the fabrication of good quality MgB2 thin films do not allow the nanostructuring approach based on the lift-off technique, we structured the samples combining EBL, optical lithography, and Ar milling. In this way, reproducible nanowires 1 μm long have been obtained. To illustrate the impact of the MgB2 film processing on its superconducting properties, we measured the temperature dependence of the resistance on a nanowire and compared it to the original magnesium diboride film. The electrical properties of the films are not degraded as a consequence of the nanostructuring process, so that superconducting nanodevices may be obtained by this method.

  19. A Novel Bio-carrier Fabricated Using 3D Printing Technique for Wastewater Treatment.

    PubMed

    Dong, Yang; Fan, Shu-Qian; Shen, Yu; Yang, Ji-Xiang; Yan, Peng; Chen, You-Peng; Li, Jing; Guo, Jin-Song; Duan, Xuan-Ming; Fang, Fang; Liu, Shao-Yang

    2015-01-01

    The structure of bio-carriers is one of the key operational characteristics of a biofilm reactor. The goal of this study is to develop a series of novel fullerene-type bio-carriers using the three-dimensional printing (3DP) technique. 3DP can fabricate bio-carriers with more specialized structures compared with traditional fabrication processes. In this research, three types of fullerene-type bio-carriers were fabricated using the 3DP technique and then compared with bio-carrier K3 (from AnoxKaldnes) in the areas of physicochemical properties and biofilm growth. Images acquired by 3D profiling and SEM indicated that the surface roughness of the 3DP bio-carrier was greater than that of K3. Furthermore, contact angle data indicated that the 3DP bio-carriers were more hydrophilic than K3. The biofilm on the 3DP bio-carriers exhibited higher microbial activity and stronger adhesion ability. These findings were attributed to excellent mass transfer of the substrate (and oxygen) between the vapour-liquid-solid tri-phase system and to the surface characteristics. It is concluded that the novel 3DP fullerene-type bio-carriers are ideal carriers for biofilm adherence and growth. PMID:26202477

  20. A Novel Bio-carrier Fabricated Using 3D Printing Technique for Wastewater Treatment

    PubMed Central

    Dong, Yang; Fan, Shu-Qian; Shen, Yu; Yang, Ji-Xiang; Yan, Peng; Chen, You-Peng; Li, Jing; Guo, Jin-Song; Duan, Xuan-Ming; Fang, Fang; Liu, Shao-Yang

    2015-01-01

    The structure of bio-carriers is one of the key operational characteristics of a biofilm reactor. The goal of this study is to develop a series of novel fullerene-type bio-carriers using the three-dimensional printing (3DP) technique. 3DP can fabricate bio-carriers with more specialized structures compared with traditional fabrication processes. In this research, three types of fullerene-type bio-carriers were fabricated using the 3DP technique and then compared with bio-carrier K3 (from AnoxKaldnes) in the areas of physicochemical properties and biofilm growth. Images acquired by 3D profiling and SEM indicated that the surface roughness of the 3DP bio-carrier was greater than that of K3. Furthermore, contact angle data indicated that the 3DP bio-carriers were more hydrophilic than K3. The biofilm on the 3DP bio-carriers exhibited higher microbial activity and stronger adhesion ability. These findings were attributed to excellent mass transfer of the substrate (and oxygen) between the vapour-liquid-solid tri-phase system and to the surface characteristics. It is concluded that the novel 3DP fullerene-type bio-carriers are ideal carriers for biofilm adherence and growth. PMID:26202477

  1. Focused ion beam techniques for fabricating geometrically-complex components and devices.

    SciTech Connect

    Mayer, Thomas Michael; Adams, David Price; Hodges, V. Carter; Vasile, Michael J.

    2004-03-01

    We have researched several new focused ion beam (FIB) micro-fabrication techniques that offer control of feature shape and the ability to accurately define features onto nonplanar substrates. These FIB-based processes are considered useful for prototyping, reverse engineering, and small-lot manufacturing. Ion beam-based techniques have been developed for defining features in miniature, nonplanar substrates. We demonstrate helices in cylindrical substrates having diameters from 100 {micro}m to 3 mm. Ion beam lathe processes sputter-define 10-{micro}m wide features in cylindrical substrates and tubes. For larger substrates, we combine focused ion beam milling with ultra-precision lathe turning techniques to accurately define 25-100 {micro}m features over many meters of path length. In several cases, we combine the feature defining capability of focused ion beam bombardment with additive techniques such as evaporation, sputter deposition and electroplating in order to build geometrically-complex, functionally-simple devices. Damascene methods that fabricate bound, metal microcoils have been developed for cylindrical substrates. Effects of focused ion milling on surface morphology are also highlighted in a study of ion-milled diamond.

  2. Modelling, Simulation, Fabrication, Experiments and Real-Time Linear State Variable Feedback Control of Cuk Converter using Pole Placement Technique

    NASA Astrophysics Data System (ADS)

    Nanda, S.; Sengupta, M.; Sengupta, A.

    2014-01-01

    Using a suitable combination of some of the basic converter topologies representing the Buck, the Boost and the Buck-Boost converters, one may obtain some other useful dc-to-dc converters. A typical example is the cascade connection of the Boost and the Buck converter which produces the well known Cuk converter. This work emphasises on the modelling, real-time simulations, fabrication and closed-loop control of a Cuk converter. For the modelling and real time simulation, FPGA platform has been used. Small signal modelling and conventional control aspects (compensator) of Cuk converter are discussed. A 200W, 10kHz Cuk converter is designed, fabricated and tested in the laboratory. The converter model is of fourth order. The transfer function being a non-minimum phase one with two right-half plane zeroes, a limited work has been done on this. For such systems, conventional control methods are demonstrated to fail. Pole placement technique, which is envisaged to be a suitable control technique for a higher order non-minimum phase system has been adopted. Excellent correlation between off-line and real-time simulation results establishes the accuracy of the work. Agreement between open-loop results obtained from the experimental set-up under steady state vis-a-vis those obtained from simulation is also a major highlight of the paper.

  3. Fatigue Life of Titanium Alloys Fabricated by Additive Layer Manufacturing Techniques for Dental Implants

    NASA Astrophysics Data System (ADS)

    Chan, Kwai S.; Koike, Marie; Mason, Robert L.; Okabe, Toru

    2013-02-01

    Additive layer deposition techniques such as electron beam melting (EBM) and laser beam melting (LBM) have been utilized to fabricate rectangular plates of Ti-6Al-4V with extra low interstitial (ELI) contents. The layer-by-layer deposition techniques resulted in plates that have different surface finishes which can impact significantly on the fatigue life by providing potential sites for fatigue cracks to initiate. The fatigue life of Ti-6Al-4V ELI alloys fabricated by EBM and LBM deposition techniques was investigated by three-point testing of rectangular beams of as-fabricated and electro-discharge machined surfaces under stress-controlled conditions at 10 Hz until complete fracture. Fatigue life tests were also performed on rolled plates of Ti-6Al-4V ELI, regular Ti-6Al-4V, and CP Ti as controls. Fatigue surfaces were characterized by scanning electron microscopy to identify the crack initiation site in the various types of specimen surfaces. The fatigue life data were analyzed statistically using both analysis of variance techniques and the Kaplan-Meier survival analysis method with the Gehan-Breslow test. The results indicate that the LBM Ti-6Al-4V ELI material exhibits a longer fatigue life than the EBM counterpart and CP Ti, but a shorter fatigue life compared to rolled Ti-6Al-4V ELI. The difference in the fatigue life behavior may be largely attributed to the presence of rough surface features that act as fatigue crack initiation sites in the EBM material.

  4. Low loss silicon waveguides and grating couplers fabricated using anisotropic wet etching technique

    NASA Astrophysics Data System (ADS)

    Debnath, Kapil; Arimoto, Hideo; Husain, Muhammad; Prasmusinto, Alyssa; Al-Attili, Abdelrahman; Petra, Rafidah; Chong, Harold; Reed, Graham; Saito, Shinichi

    2016-02-01

    We report low-loss silicon waveguides and efficient grating coupler to couple light into them. By using anisotropic wet etching technique, we reduced the side wall roughness down to 1.2nm. The waveguides were patterned along the [112] direction on a [110] SOI substrate. The waveguide boundaries are decided by the [111] planes which are normal to the [110] surface. Fabricated waveguides show minimum propagation loss of 0.85 dB/cm for TE polarization and 1.08dB/cm for TM polarization. The fabricated grating couplers show coupling efficiency of -4.16dB at 1570nm with 3dB bandwidth of 46nm.

  5. Quantitative characterization of X-ray lenses from two fabrication techniques with grating interferometry.

    PubMed

    Koch, Frieder J; Detlefs, Carsten; Schröter, Tobias J; Kunka, Danays; Last, Arndt; Mohr, Jürgen

    2016-05-01

    Refractive X-ray lenses are in use at a large number of synchrotron experiments. Several materials and fabrication techniques are available for their production, each having their own strengths and drawbacks. We present a grating interferometer for the quantitative analysis of single refractive X-ray lenses and employ it for the study of a beryllium point focus lens and a polymer line focus lens, highlighting the differences in the outcome of the fabrication methods. The residuals of a line fit to the phase gradient are used to quantify local lens defects, while shape aberrations are quantified by the decomposition of the retrieved wavefront phase profile into either Zernike or Legendre polynomials, depending on the focus and aperture shape. While the polymer lens shows better material homogeneity, the beryllium lens shows higher shape accuracy. PMID:27137533

  6. Curved grating fabrication techniques for concentric-circle grating, surface-emitting semiconductor lasers

    NASA Technical Reports Server (NTRS)

    Jordan, Rebecca H.; King, Oliver; Wicks, Gary W.; Hall, Dennis G.; Anderson, Erik H.; Rooks, Michael J.

    1993-01-01

    We describe the fabrication and operational characteristics of a novel, surface-emitting semiconductor laser that makes use of a concentric-circle grating to both define its resonant cavity and to provide surface emission. A properly fabricated circular grating causes the laser to operate in radially inward- and outward-going circular waves in the waveguide, thus, introducing the circular symmetry needed for the laser to emit a beam with a circular cross-section. The basic circular-grating-resonator concept can be implemented in any materials system; an AlGaAs/GaAs graded-index, separate confinement heterostructure (GRINSCH), single-quantum-well (SQW) semiconductor laser, grown by molecular beam epitaxy (MBE), was used for the experiments discussed here. Each concentric-circle grating was fabricated on the surface of the AlGaAs/GaAs semiconductor laser. The circular pattern was first defined by electron-beam (e-beam) lithography in a layer of polymethylmethacrylate (PMMA) and subsequently etched into the semiconductor surface using chemically-assisted (chlorine) ion-beam etching (CAIBE). We consider issues that affect the fabrication and quality of the gratings. These issues include grating design requirements, data representation of the grating pattern, and e-beam scan method. We provide examples of how these techniques can be implemented and their impact on the resulting laser performance. A comparison is made of the results obtained using two fundamentally different electron-beam writing systems. Circular gratings with period lambda = 0.25 microns and overall diameters ranging from 80 microns to 500 microns were fabricated. We also report our successful demonstration of an optically pumped, concentric-circle grating, semiconductor laser that emits a beam with a far-field divergence angle that is less than one degree. The emission spectrum is quite narrow (less than 0.1 nm) and is centered at wavelength lambda = 0.8175 microns.

  7. Innovative sputtering techniques for CIS and CdTe submodule fabrication. Annual subcontract report, 1 September 1991--31 August 1992

    SciTech Connect

    Armstrong, J.M.; Misra, M.S.; Lanning, B.

    1993-03-01

    This report describes work done during Phase 1 of the subject subcontract. The subcontract was designed to study innovative deposition techniques, such as the rotating cylindrical magnetron sputtering system and electrodeposition for large-area, low-cost copper indium diselenide (CIS) and cadmium telluride (CdTe) devices. A key issue for photovoltaics (PV) in terrestrial and future space applications is producibility, particularly for applications using a large quantity of PV. Among the concerns for fabrication of polycrystalline thin-film PV, such as CIS and CdTe, are production volume, cost, and minimization of waste. Both rotating cylindrical magnetron (C-Mag{trademark}) sputtering and electrodeposition have tremendous potential for the fabrication of polycrystalline thin-film PV due to scaleability, efficient utilization of source materials, and inherently higher deposition rates. In the case of sputtering, the unique geometry of the C-Mae facilitates innovative cosputtering and reactive sputtering that could lead to greater throughput reduced health and safety risks, and, ultimately, lower fabrication cost. Electrodeposited films appear to be adherent and comparable with low-cost fabrication techniques. Phase I involved the initial film and device fabrication using the two techniques mentioned herein. Devices were tested by both internal facilities, as well as NREL and ISET.

  8. Resonant marker design and fabrication techniques for device visualization during interventional magnetic resonance imaging.

    PubMed

    Kaiser, Mandy; Detert, Markus; Rube, Martin A; El-Tahir, Abubakr; Elle, Ole Jakob; Melzer, Andreas; Schmidt, Bertram; Rose, Georg H

    2015-04-01

    Magnetic resonance imaging (MRI) has great potential as an imaging modality for guiding minimally invasive interventions because of its superior soft tissue contrast and the possibility of arbitrary slice positioning while avoiding ionizing radiation and nephrotoxic iodine contrast agents. The major constraints are: limited patient access, the insufficient assortment of compatible instruments and the difficult device visualization compared to X-ray based techniques. For the latter, resonant MRI markers, fabricated by using the wire-winding technique, have been developed. This fabrication technique serves as a functional model but has no clinical use. Thus, the aim of this study is to illustrate a four-phase design process of resonant markers involving microsystems technologies. The planning phase comprises the definition of requirements and the simulation of electromagnetic performance of the MRI markers. The following technologies were considered for the realization phase: aerosol-deposition process, hot embossing technology and thin film technology. The subsequent evaluation phase involves several test methods regarding electrical and mechanical characterization as well as MRI visibility aspects. The degree of fulfillment of the predefined requirements is determined within the analysis phase. Furthermore, an exemplary evaluation of four realized MRI markers was conducted, focusing on the performance within the MRI environment. PMID:25460277

  9. Antiwetting Fabric Produced by a Combination of Layer-by-Layer Assembly and Electrophoretic Deposition of Hydrophobic Nanoparticles.

    PubMed

    Joung, Young Soo; Buie, Cullen R

    2015-09-16

    This work describes a nanoparticle coating method to produce durable antiwetting polyester fabric. Electrophoretic deposition is used for fast modification of polyester fabric with silica nanoparticles embedded in polymeric networks for high durability coatings. Typically, electrophoretic deposition (EPD) is utilized on electrically conductive substrates due to its dependence on an applied electrical field. EPD on nonconductive materials has been attempted but are limited by weak adhesion, cracks, and other irregularities. To resolve these issues, we coat polyester fabric with thin polymer layers using electrostatic self-assembly (layer-by-layer self-assembly). Next, silica nanoparticles are uniformly dispersed on the polymer layers. Finally, polymerically stabilized silica nanoparticles are deposited by EPD on the fabric, followed by heat treatment. The modified fabric shows high static contact angle and low contact angle hysteresis, while keeping its original color, flexibility, and air permeability. During a skin fiction resistance test, the hydrophobicity of the coating layer was maintained over 500 h. Furthermore, we also show that this approach facilitates patterned regions of wettability by modifying the electric field in EPD. PMID:26312560

  10. Specific fabrication techniques of the Polo Model coil and its components

    SciTech Connect

    Friesinger, G.; Forster, S.; Jeske, U.; Nyilas, A.; Schenk, G.; Schmidt, C.; Siewerdt, L.; Susser, M.; Ulbricht, A.; Wuchner, F. . Inst. fuer Technische Physik); Bonnet, P.; Bourquard, A.; Ferry, P.J. )

    1992-01-01

    Poloidal field coils of tokamak machines are characterized by their pulsed operation needed for plasma ramp up and control. They have to sustain operation faults like plasma disruptions in their superconducting state. A low loss conductor, low loss structural reinforcement and a high voltage insulation system are needed for fulfilling these requirements. The basis for this technology has been developed for a superconducting model coil which is being manufactured by GEC Alsthom, Belfort and which will be tested at the KfK Karlsruhe. In this paper the fabrication technique applied for the coil and some high voltage related components are described.

  11. Sensing and identification of carbon monoxide using carbon films fabricated by methane arc discharge decomposition technique.

    PubMed

    Akbari, Elnaz; Buntat, Zolkafle; Enzevaee, Aria; Yazdi, Mahsa Khoshkhooy; Bahadoran, Mahdi; Nikoukar, Ali

    2014-01-01

    Carbonaceous materials have recently received attention in electronic applications and measurement systems. In this work, we demonstrate the electrical behavior of carbon films fabricated by methane arc discharge decomposition technique. The current-voltage (I-V) characteristics of carbon films are investigated in the presence and absence of gas. The experiment reveals that the current passing through the carbon films increases when the concentration of CO2 gas is increased from 200 to 800 ppm. This phenomenon which is a result of conductance changes can be employed in sensing applications such as gas sensors. PMID:25177219

  12. A novel cost effective fabrication technique for highly preferential oriented TiO2 nanotubes.

    PubMed

    K, Aijo John; Naduvath, Johns; Mallick, Sudhanshu; Shripathi, Thoudinja; Thankamoniamma, Manju; Philip, Rachel Reena

    2015-12-28

    Single crystal like TiO(2) nanotubes with preferential orientation along the [001] direction, parallel to the growth direction of nanotubes, that offer ease of charge transport much higher than reported so far, are fabricated using a cost effective two step technique. The success of this method to grow the nanotubes with the anomalous intense [001] preferential orientation is attributed to the zinc assisted minimization of the (001) surface energy. The single crystal like TiO(2) nanotubes show superior performance as supercapacitor electrodes compared to the normal polycrystalline titanium dioxide nanotubes. PMID:26602105

  13. Fabrication of multi-walled carbon nanotubes-aluminum matrix composite by powder metallurgy technique

    NASA Astrophysics Data System (ADS)

    Bunakov, N. A.; Kozlov, D. V.; Golovanov, V. N.; Klimov, E. S.; Grebchuk, E. E.; Efimov, M. S.; Kostishko, B. B.

    We report on fabrication of an aluminum matrix composite containing multi-walled carbon nanotubes (MWCNTs) produced by MOCVD method and functionalized via acid treatment by a H2SO4/HNO3 mixture. Specimens were prepared by spark plasma sintering (SPS) of the aluminum powder with different amounts of functionalized MWCNTs (FMWCNTs) in the range of 0.1-1 wt.%. We studied the effect of FMWCNTs amount on microstructure and mechanical properties of composites. It is shown that functionalization allows homogeneous dispersing of the MWCNTs in Al powder. The maximal increase in micro-hardness and tensile strength is registered at 0.1 wt.%.

  14. Low temperature fabrication of conductive silver lines and dots via transfer-printing and nanoimprinting lithography techniques

    NASA Astrophysics Data System (ADS)

    Wu, Chun-Chang; Lien-Chung Hsu, Steve; Chiu, Ching-Wei; Wu, Jung-Tang

    2013-08-01

    In this work, we have developed novel methods to fabricate conductive silver tracks and dots directly from silver nitrate solution by transfer-printing and nanoimprinting lithography techniques, which are inexpensive and can be scaled down to the nanometer scale. The silver nitrate precursor can be reduced in ethylene glycol vapor to form silver at low temperatures. Energy dispersive spectrometric analysis results indicate that the silver nitrate has been converted to silver completely. In order to obtain smooth and continuous conductive patterned silver features with high resolution, the silver lines with widths of a few tens of micrometers to nanometers were patterned by using a spin-coating approach. Using a 14 M silver nitrate solution, continuous silver conductive lines with a resistivity of 8.45 × 10-5 Ω cm has been produced.

  15. Fabrication of low-cost, cementless femoral stem 316L stainless steel using investment casting technique.

    PubMed

    Baharuddin, Mohd Yusof; Salleh, Sh-Hussain; Suhasril, Andril Arafat; Zulkifly, Ahmad Hafiz; Lee, Muhammad Hisyam; Omar, Mohd Afian; Abd Kader, Ab Saman; Mohd Noor, Alias; A Harris, Arief Ruhullah; Abdul Majid, Norazman

    2014-07-01

    Total hip arthroplasty is a flourishing orthopedic surgery, generating billions of dollars of revenue. The cost associated with the fabrication of implants has been increasing year by year, and this phenomenon has burdened the patient with extra charges. Consequently, this study will focus on designing an accurate implant via implementing the reverse engineering of three-dimensional morphological study based on a particular population. By using finite element analysis, this study will assist to predict the outcome and could become a useful tool for preclinical testing of newly designed implants. A prototype is then fabricated using 316L stainless steel by applying investment casting techniques that reduce manufacturing cost without jeopardizing implant quality. The finite element analysis showed that the maximum von Mises stress was 66.88 MPa proximally with a safety factor of 2.39 against endosteal fracture, and micromotion was 4.73 μm, which promotes osseointegration. This method offers a fabrication process of cementless femoral stems with lower cost, subsequently helping patients, particularly those from nondeveloped countries. PMID:24404766

  16. Characterization of fabricated three dimensional scaffolds of bioceramic-polymer composite via microstereolithography technique

    NASA Astrophysics Data System (ADS)

    Talib, Marina; Covington, James A.; Bolarinwa, Aminat

    2014-02-01

    Microstereolithography is a method used for rapid prototyping of polymeric and ceramic components. This technique converts a computer-aided design (CAD) to a three dimensional (3D) model, and enables layer per layer fabrication curing a liquid resin with UV-light or laser source. The aim of this project was to formulate photocurable polymer reinforced with synthesized calcium pyrophosphate (CPP), and to fabricate a 3D scaffolds with optimum mechanical properties for specific tissue engineering applications. The photocurable ceramic suspension was prepared with acrylate polyester, multifunctional acrylate monomer with the addition of 50-70wt% of CPP, photoinitiators and photoinhibitors. The 3D structure of disc (5 mm height × 4 mm diameter) was successfully fabricated using Envisiontec Perfactory3® . They were then sintered at high temperature for polymer removal, to obtain a ceramic of the desired porosity. The density increased to more than 35% and the dimensional shrinkage after sintering were 33%. The discs were then subjected compressive measurement, biodegradation and bioactivity test. Morphology and CPP content of the sintered polymer was investigated with SEM and XRD, respectively. The addition of CPP coupled with high temperature sintering, had a significant effect on the compressive strength exhibited by the bioceramic. The values are in the range of cancellous bone (2-4 MPa). In biodegradation and bioactivity test, the synthesized CPP induced the formation of apatite layer and its nucleation onto the composite surface.

  17. A novel fabrication method of silicon nano-needles using MEMS TMAH etching techniques.

    PubMed

    Yan, Sheping; Xu, Yang; Yang, Junyi; Wang, Huiquan; Jin, Zhonghe; Wang, Yuelin

    2011-03-25

    Nano-needles play important roles in nanoscale operations. However, current nano-needle fabrication is usually expensive and controling the sizes and angles is complicated. We have developed a simple and low cost silicon nano-needle fabrication method using traditional microelectromechanical system (MEMS) tetramethyl ammonium hydroxide (TMAH) etching techniques. We take advantage of the fact that the decrease of the silicon etch rate in TMAH solutions exhibits an inverse fourth power dependence on the boron doping concentration in our nano-needle fabrication. Silicon nano-needles, with high aspect ratio and sharp angles θ as small as 2.9°, are obtained, which could be used for bio-sensors and nano-handling procedures, such as penetrating living cells. An analytic model is proposed to explain the etching evolution of the experimental results, which is used to predict the needle angle, length, and etching time. Based on our method, nano-needles with small acute angle θ can be obtained. PMID:21317492

  18. A novel fabrication method of silicon nano-needles using MEMS TMAH etching techniques

    NASA Astrophysics Data System (ADS)

    Yan, Sheping; Xu, Yang; Yang, Junyi; Wang, Huiquan; Jin, Zhonghe; Wang, Yuelin

    2011-03-01

    Nano-needles play important roles in nanoscale operations. However, current nano-needle fabrication is usually expensive and controling the sizes and angles is complicated. We have developed a simple and low cost silicon nano-needle fabrication method using traditional microelectromechanical system (MEMS) tetramethyl ammonium hydroxide (TMAH) etching techniques. We take advantage of the fact that the decrease of the silicon etch rate in TMAH solutions exhibits an inverse fourth power dependence on the boron doping concentration in our nano-needle fabrication. Silicon nano-needles, with high aspect ratio and sharp angles θ as small as 2.9°, are obtained, which could be used for bio-sensors and nano-handling procedures, such as penetrating living cells. An analytic model is proposed to explain the etching evolution of the experimental results, which is used to predict the needle angle, length, and etching time. Based on our method, nano-needles with small acute angle θ can be obtained.

  19. Novel Technique Using Polyester Fabric and Fibrin Sealant Patch for Acute Aortic Dissection.

    PubMed

    Ohira, Suguru; Fukumoto, Atsushi; Matsushiro, Takuya; Yaku, Hitoshi

    2016-08-01

    We describe a simple and effective technique for acute aortic dissection using a combination of polyester fabric and a fibrin sealant patch (FSP) to achieve effective reinforcement and haemostasis of the aortic stump. Firstly, the 0.61mm thick knitted polyester fabric sheet was cut to half of the size of the FSP. Next, fibrin glue was sprayed onto the collagen layer of the FSP. Subsequently, a fabric sheet was placed upon it, and the FSP was put together with the irrigated collagen layer, and then completely dried to bind the patch. As a result, the dry fibrinogen/thrombin layers, as an adhesive surface, faced outward. This patch was trimmed to a 10-15-mm-wide strip. The composite patch was inserted into the false lumen. The stump was gently pressed to fix the aortic intima and adventitia. There are several advantages: the combined patch can be prepared during systemic cooling, and therefore can minimise the circulatory arrest time; secondly, the false lumen is not directly exposed to fibrin glue and so the risk of embolism is extremely low; thirdly, the expected haemostatic effect is greater as FSP lines the exterior of the intima, achieving haemostasis for suture holes. PMID:27011040

  20. Fabrication techniques and properties of multifilamentary Nb/sub 3/Sn conductors

    SciTech Connect

    Suenaga, M; Sampson, W B; Luhman, T S

    1980-01-01

    Various processing techniques for multifilamentary Nb/sub 3/Sn and V/sub 3/Ga are reviewed. The critical current of commercially produced Nb/sub 3/Sn wires manufactured by both the bronze and external diffusion techniques are compared. Critical currents for in situ and powder processed Nb/sub 3/Sn are also included. New developments which promise improvements in J/sub c/ are discussed.

  1. Simple technique for fabrication of shielding blocks for total body irradiation at extended treatment distances

    PubMed Central

    Ravichandran, R.; Binukumar, J. P.; Davis, C. A.; Zahid, A. M.; Rajan, B.

    2009-01-01

    Techniques are being standardized in our department for total body irradiation (TBI) with six MV photons in linear accelerator for preconditioning to bone marrow transplantation (BMT). Individualized shields with low melting point alloy are to be fabricated for shielding critical organs such as lungs, kidneys etc. A method to mount diminished dimension of shields in a tray at 3.75m is designed in the department for a teletreatment distance of four meters with magna field with A simulator image taken with the patient's midplane (MP) at one meter distance is used to mark the dimensions of lung, scaled down by a factor of 3.75/4.0. These lung dimensions are reprinted from the digital simulator image for making the shield. The methodology of the technique using digitized minification in radiography is the first of its kind to be used for shield cutting in magna field radiotherapy. PMID:20098553

  2. Fabrication technique for a custom face mask for the treatment of obstructive sleep apnea.

    PubMed

    Prehn, Ronald S; Colquitt, Tom

    2016-05-01

    The development of the positive airway pressure custom mask (TAP-PAP CM) has changed the treatment of obstructive sleep apnea. The TAP-PAP CM is used in continuous positive airway pressure therapy (CPAP) and is fabricated from the impression of the face. This mask is then connected to a post screwed into the mechanism of the TAP3 (Thornton Anterior Positioner) oral appliance. This strapless CPAP face mask features an efficient and stable CPAP interface with mandibular stabilization (Hybrid Therapy). A technique with a 2-stage polyvinyl siloxane face impression is described that offers improvements over the established single-stage face impression. This 2-stage impression technique eliminates problems inherent in the single-stage face impression, including voids, compressed tissue, inadequate borders, and a rushed experience due to the setting time of the single stage. The result is a custom mask with an improved seal to the CPAP device. PMID:26774315

  3. Technique for fabricating individualized dentures with a gingiva-shade composite resin.

    PubMed

    Park, Beom-Woo; Kim, Nam-Jin; Lee, Jonghyuk; Lee, Hae-Hyoung

    2016-05-01

    More natural dental esthetics have been sought by patients who wear conventional complete or partial dentures. Recently, gingiva-shade composite resins (GSCRs) have become available for replicating soft tissue for both fixed and removable prostheses. The technique presented is for fabricating individualized complete dentures. First the acrylic resin is mixed with a coloring agent and processed to modify the base shade of the denture. GSCRs are light polymerized onto a prepared space on the buccal surfaces of denture base to replicate the appearance of gingival tissues including blood vessels. The technique provides an outstanding natural, gingiva-like, appearance and allows complete dentures to harmonize with the individual patient's surrounding oral tissues. PMID:26794697

  4. NOTE: Investigation of a copper etching technique to fabricate metallic gas diffusion media

    NASA Astrophysics Data System (ADS)

    Zhang, Feng-Yuan; Prasad, Ajay K.; Advani, Suresh G.

    2006-11-01

    A new fabrication technique based on etching is employed to convert a copper foil into a porous structure with an array of micron size pores. The motivation stems from the need to develop a more efficient and controllable gas diffusion medium for fuel cell applications. The influence of mask shape, mask width and etching time was investigated experimentally. A correlation to predict trench width with etching time was derived; normalizing by mask width allows one to collapse the data. The etching rates to obtain micro-scale features, which are of the order of 1 2 µm min 1, are mainly dominated by the mask width due to mass-transport resistance. It is possible to control the pore dimensions, porosity and pore size distributions with this technique.

  5. A novel fabrication technique to minimize poly(dimethylsiloxane)-microchannels deformation under high-pressure operation.

    PubMed

    Madadi, Hojjat; Mohammadi, Mahdi; Casals-Terré, Jasmina; López, Roberto Castilla

    2013-12-01

    PDMS is one of the most common materials used for the flow delivery in the microfluidics chips, since it is clear, inert, nontoxic, and nonflammable. Its inexpensiveness, straightforward fabrication, and biological compatibility have made it a favorite material in the exploratory stages of the bio-microfluidic devices. If small footprint assays want to be performed while keeping the throughput, high pressure-rated channels should be used, but PDMS flexibility causes an important issue since it can generate a large variation of microchannel geometry. In this work, a novel fabrication technique based on the prevention of PDMS deformation is developed. A photo-sensible thiolene resin (Norland Optical Adhesive 63, NOA 63) is used to create a rigid coating layer over the stiff PDMS micropillar array, which significantly reduces the pressure-induced shape changes. This method uses the exact same soft lithography manufacturing equipment. The verification of the presented technique was investigated experimentally and numerically and the manufactured samples showed a deformation 70% lower than PDMS conventional samples. PMID:24114728

  6. Fabrication of capacitive acoustic resonators combining 3D printing and 2D inkjet printing techniques.

    PubMed

    Haque, Rubaiyet Iftekharul; Ogam, Erick; Loussert, Christophe; Benaben, Patrick; Boddaert, Xavier

    2015-01-01

    A capacitive acoustic resonator developed by combining three-dimensional (3D) printing and two-dimensional (2D) printed electronics technique is described. During this work, a patterned bottom structure with rigid backplate and cavity is fabricated directly by a 3D printing method, and then a direct write inkjet printing technique has been employed to print a silver conductive layer. A novel approach has been used to fabricate a diaphragm for the acoustic sensor as well, where the conductive layer is inkjet-printed on a pre-stressed thin organic film. After assembly, the resulting structure contains an electrically conductive diaphragm positioned at a distance from a fixed bottom electrode separated by a spacer. Measurements confirm that the transducer acts as capacitor. The deflection of the diaphragm in response to the incident acoustic single was observed by a laser Doppler vibrometer and the corresponding change of capacitance has been calculated, which is then compared with the numerical result. Observation confirms that the device performs as a resonator and provides adequate sensitivity and selectivity at its resonance frequency. PMID:26473878

  7. Fabrication of Capacitive Acoustic Resonators Combining 3D Printing and 2D Inkjet Printing Techniques

    PubMed Central

    Haque, Rubaiyet Iftekharul; Ogam, Erick; Loussert, Christophe; Benaben, Patrick; Boddaert, Xavier

    2015-01-01

    A capacitive acoustic resonator developed by combining three-dimensional (3D) printing and two-dimensional (2D) printed electronics technique is described. During this work, a patterned bottom structure with rigid backplate and cavity is fabricated directly by a 3D printing method, and then a direct write inkjet printing technique has been employed to print a silver conductive layer. A novel approach has been used to fabricate a diaphragm for the acoustic sensor as well, where the conductive layer is inkjet-printed on a pre-stressed thin organic film. After assembly, the resulting structure contains an electrically conductive diaphragm positioned at a distance from a fixed bottom electrode separated by a spacer. Measurements confirm that the transducer acts as capacitor. The deflection of the diaphragm in response to the incident acoustic single was observed by a laser Doppler vibrometer and the corresponding change of capacitance has been calculated, which is then compared with the numerical result. Observation confirms that the device performs as a resonator and provides adequate sensitivity and selectivity at its resonance frequency. PMID:26473878

  8. A novel cost effective fabrication technique for highly preferential oriented TiO2 nanotubes

    NASA Astrophysics Data System (ADS)

    John K, Aijo; Naduvath, Johns; Mallick, Sudhanshu; Shripathi, Thoudinja; Thankamoniamma, Manju; Philip, Rachel Reena

    2015-12-01

    Single crystal like TiO2 nanotubes with preferential orientation along the [001] direction, parallel to the growth direction of nanotubes, that offer ease of charge transport much higher than reported so far, are fabricated using a cost effective two step technique. The success of this method to grow the nanotubes with the anomalous intense [001] preferential orientation is attributed to the zinc assisted minimization of the (001) surface energy. The single crystal like TiO2 nanotubes show superior performance as supercapacitor electrodes compared to the normal polycrystalline titanium dioxide nanotubes.Single crystal like TiO2 nanotubes with preferential orientation along the [001] direction, parallel to the growth direction of nanotubes, that offer ease of charge transport much higher than reported so far, are fabricated using a cost effective two step technique. The success of this method to grow the nanotubes with the anomalous intense [001] preferential orientation is attributed to the zinc assisted minimization of the (001) surface energy. The single crystal like TiO2 nanotubes show superior performance as supercapacitor electrodes compared to the normal polycrystalline titanium dioxide nanotubes. Electronic supplementary information (ESI) available. See DOI: 10.1039/c5nr06328k

  9. A new method of fabricating a blend scaffold using an indirect three-dimensional printing technique.

    PubMed

    Jung, Jin Woo; Lee, Hyungseok; Hong, Jung Min; Park, Jeong Hun; Shim, Jung Hee; Choi, Tae Hyun; Cho, Dong-Woo

    2015-01-01

    Due to its simplicity and effectiveness, the physical blending of polymers is considered to be a practical strategy for developing a versatile scaffold having desirable mechanical and biochemical properties. In the present work, an indirect three-dimensional (i3D) printing technique was proposed to fabricate a 3D free-form scaffold using a blend of immiscible materials, such as polycaprolactone (PCL) and gelatin. The i3D printing technique includes 3D printing of a mold and a sacrificial molding process. PCL/chloroform and gelatin/water were physically mixed to prepare the blend solution, which was subsequently injected into the cavity of a 3D printed mold. After solvent removal and gelatin cross-linking, the mold was dissolved to obtain a PCL-gelatin (PG) scaffold, with a specific 3D structure. Scanning electron microscopy and Fourier transform infrared spectroscopy analysis indicated that PCL masses and gelatin fibers in the PG scaffold homogenously coexisted without chemical bonding. Compression tests confirmed that gelatin incorporation into the PCL enhanced its mechanical flexibility and softness, to the point of being suitable for soft-tissue engineering, as opposed to pure PCL. Human adipose-derived stem cells, cultured on a PG scaffold, exhibited enhanced in vitro chondrogenic differentiation and tissue formation, compared with those on a PCL scaffold. The i3D printing technique can be used to blend a variety of materials, facilitating 3D scaffold fabrication for specific tissue regeneration. Furthermore, this convenient and versatile technique may lead to wider application of 3D printing in tissue engineering. PMID:26525821

  10. Metallurgical Mechanisms Controlling Mechanical Properties of Aluminum Alloy 2219 Produced by Electron Beam Freeform Fabrication

    NASA Technical Reports Server (NTRS)

    Domack, Marcia S.; Tainger, Karen M.

    2006-01-01

    The electron beam freeform fabrication (EBF3) layer-additive manufacturing process has been developed to directly fabricate complex geometry components. EBF3 introduces metal wire into a molten pool created on the surface of a substrate by a focused electron beam. Part geometry is achieved by translating the substrate with respect to the beam to build the part one layer at a time. Tensile properties demonstrated for electron beam deposited aluminum and titanium alloys are comparable to wrought products, although the microstructures of the deposits exhibit cast features. Understanding the metallurgical mechanisms controlling mechanical properties is essential to maximizing application of the EBF3 process. Tensile mechanical properties and microstructures were examined for aluminum alloy 2219 fabricated over a range of EBF3 process variables. Unique microstructures were observed within the deposited layers and at interlayer boundaries, which varied within the deposit height due to microstructural evolution associated with the complex thermal history experienced during subsequent layer deposition. Microstructures exhibited irregularly shaped grains with interior dendritic structures, described based on overall grain size, morphology, distribution, and dendrite spacing, and were correlated with deposition parameters. Fracture features were compared with microstructural elements to define fracture paths and aid in definition of basic processing-microstructure-property correlations.

  11. Metallurgical Mechanisms Controlling Mechanical Properties of Aluminum Alloy 2219 Produced By Electron Beam Freeform Fabrication

    NASA Technical Reports Server (NTRS)

    Domack, Marcia S.; Taminger, Karen M. B.; Begley, Matthew

    2006-01-01

    The electron beam freeform fabrication (EBF3) layer-additive manufacturing process has been developed to directly fabricate complex geometry components. EBF3 introduces metal wire into a molten pool created on the surface of a substrate by a focused electron beam. Part geometry is achieved by translating the substrate with respect to the beam to build the part one layer at a time. Tensile properties have been demonstrated for electron beam deposited aluminum and titanium alloys that are comparable to wrought products, although the microstructures of the deposits exhibit features more typical of cast material. Understanding the metallurgical mechanisms controlling mechanical properties is essential to maximizing application of the EBF3 process. In the current study, mechanical properties and resulting microstructures were examined for aluminum alloy 2219 fabricated over a range of EBF3 process variables. Material performance was evaluated based on tensile properties and results were compared with properties of Al 2219 wrought products. Unique microstructures were observed within the deposited layers and at interlayer boundaries, which varied within the deposit height due to microstructural evolution associated with the complex thermal history experienced during subsequent layer deposition. Microstructures exhibited irregularly shaped grains, typically with interior dendritic structures, which were described based on overall grain size, morphology, distribution, and dendrite spacing, and were correlated with deposition parameters. Fracture features were compared with microstructural elements to define fracture paths and aid in definition of basic processing-microstructure-property correlations.

  12. New fabrication techniques for ring-array transducers for real-time 3D intravascular ultrasound.

    PubMed

    Light, Edward D; Lieu, Victor; Smith, Stephen W

    2009-10-01

    We have previously described miniature 2D array transducers integrated into a Cook Medical, Inc. vena cava filter deployment device. While functional, the fabrication technique was very labor intensive and did not lend itself well to efficient fabrication of large numbers of devices. We developed two new fabrication methods that we believe can be used to efficiently manufacture these types of devices in greater than prototype numbers. One transducer consisted of 55 elements operating near 5 MHz. The interelement spacing is 0.20 mm. It was constructed on a flat piece of copper-clad polyimide and then wrapped around an 11 French catheter of a Cook Medical, Inc. inferior vena cava (IVC) filter deployment device. We used a braided wiring technology from Tyco Electronics Corp. to connect the elements to our real-time 3D ultrasound scanner. Typical measured transducer element bandwidth was 20% centered at 4.7 MHz and the 50 Omega round trip insertion loss was --82 dB. The mean of the nearest neighbor cross talk was -37.0 dB. The second method consisted of a 46-cm long single layer flex circuit from MicroConnex that terminates in an interconnect that plugs directly into our system cable. This transducer had 70 elements at 0.157 mm interelement spacing operating at 4.8 MHz. Typical measured transducer element bandwidth was 29% and the 50 Omega round trip insertion loss was -83 dB. The mean of the nearest neighbor cross talk was -33.0 dB. PMID:20458877

  13. Toxicity study in blood and tumor cells of laser produced medicines for application in fabrics.

    PubMed

    Morán, M Carmen; Tozar, Tatiana; Simon, Agota; Dinache, Andra; Smarandache, Adriana; Andrei, Ionut Relu; Boni, Mihai; Pascu, Mihail Lucian; Cirisano, Francesca; Ferrari, Michele

    2016-01-01

    Phenothiazine derivatives are non-antibiotics with antimicrobial, fungistatic and fungicidal effects. We exposed to a high energy UV laser beam phenothiazines solutions in water at 20mg/mL concentration to increase antibacterial activity of resulting mixtures. Compared to previous results obtained on bacteria, more research is needed about UV laser irradiated phenothiazines applications on cancer cell cultures to evidence possible anticancerous properties. Evaluation of the safety of the newly obtained photoproducts in view of use on humans is also needed. Due to expensive animal testing in toxicology and pressure from general public and governments to develop alternatives to in vivo testing, in vitro cell-based models are attractive for preliminary testing of new materials. Cytotoxicity screening reported here shows that laser irradiated (4h exposure time length) chlorpromazine and promazine are more efficient against some cell cultures. Interaction of laser irradiated phenothiazines with fabrics show that promethazine and chlorpromazine have improved wetting properties. Correlation of these two groups of properties shows that chlorpromazine appears to be more recommended for applications on tissues using fabrics as transport vectors. The reported results concern stability study of phenothiazines water solutions to know the time limits within which they are stable and may be used. PMID:26187648

  14. Study on fabrication of scaffold using three-dimensional electrohydrodynamic ink-jet technique

    NASA Astrophysics Data System (ADS)

    Ko, Han Seo; Lee, Soo-Hong; Lee, Pil-Ho; Kim, Dae-Hoon; Yu, Chiang Wei; Lee, Sang Won

    2013-11-01

    The EHD ink-jet technique uses the electrostatic force by applied voltage between a nozzle and an electrode to fabricate a three-dimensional scaffold by accumulating layers. In this study, a PLA (Polylactide) which is a polymer material was used to make the biodegradable scaffold. The experiment was performed by various inks with different solvent ratios because the layer thickness and width on the substrate are influenced by the ink properties such as the solvent ratio and boiling point. The cone-jet mode which looks cone-shaped on the meniscus was used for the EHD jetting by various stage velocities and solvent ratios of the PCL material. The micro-zoom lens and the LED lamp were used to visualize the jetting performance. The three-dimensional printing was completed by the movement of the stages using the Gentry structure. The optimum condition was selected for the fabrication of the scaffold after investigating the width of the pattern and the thickness of the multiple layers. This work supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Korean government (MEST) (No. S-2011-0023457).

  15. Fabrication of two dimensional polyethylene terephthalate nanofluidic chip using hot embossing and thermal bonding technique

    PubMed Central

    Yin, Zhifu; Zou, Helin; Chen, Li; Xu, Shenbo

    2014-01-01

    We present in this paper a method for obtaining a low cost and high replication precision 2D (two dimensional) nanofluidic chip with a PET (polyethylene terephthalate) sheet, which uses hot embossing and a thermal bonding technique. The hot embossing process parameters were optimized by both experiments and the finite element method to improve the replication precision of the 2D nanochannels. With the optimized process parameters, 174.67 ± 4.51 nm wide and 179.00 ± 4.00 nm deep nanochannels were successfully replicated into the PET sheet with high replication precision of 98.4%. O2 plasma treatment was carried out before the bonding process to decrease the dimension loss and improve the bonding strength of the 2D nanofluidic chip. The bonding parameters were optimized by bonding rate of the nanofluidic chip. The experiment results show that the bonding strength of the 2D PET nanofluidic chip is 0.664 MPa, and the total dimension loss of 2D nanochannels is 4.34 ± 7.03 nm and 18.33 ± 9.52 nm, in width and depth, respectively. The fluorescence images demonstrate that there is no blocking or leakage over the entire micro- and nanochannels. With this fabrication technology, low cost polymer nanochannels can be fabricated, which allows for commercial manufacturing of nano-components. PMID:25553203

  16. Hemoglobin protein hollow shells fabricated through covalent layer-by-layer technique

    SciTech Connect

    Duan Li; He Qiang; Cui Yue; Wang Kewei; Li Junbai . E-mail: jbli@iccas.ac.cn

    2007-03-09

    Hemoglobin (Hb) protein microcapsules held together by cross-linker, glutaraldehyde (GA), were successfully fabricated by covalent layer-by-layer (LbL) technique. The Schiff base reaction occurred on the colloid templates between the aldehyde groups of GA and free amino sites of Hb results in the formation of GA/Hb microcapsules after the removal of the templates. The structure of obtained monodisperse protein microcapsule was characterized by transmission electron microscopy (TEM) and confocal laser scanning microscopy (CLSM). The UV-Vis spectra measurements demonstrate the existence of Hb in the assembled capsules. Cyclic voltammetry (CV) and potential-controlled amperometric measurements (I-t curve) confirm that hemoglobin microcapsules after fabrication remain their heme electroactivity. Moreover, direct electron transfer process from protein to electrode surface was performed to detect the heme electrochemistry without using any mediator or promoter. The experiments of fluorescence recovery after photobleaching (FRAP) by CLSM demonstrate that the hemoglobin protein microcapsules have an improved permeability comparing to the conventional polyelectrolyte microcapsules.

  17. Elastomeric PDMS Planoconvex Lenses Fabricated by a Confined Sessile Drop Technique.

    PubMed

    Ekgasit, S; Kaewmanee, N; Jangtawee, P; Thammacharoen, C; Donphoongpri, M

    2016-08-10

    The ubiquity of high quality smartphones at affordable prices not only accelerated the social penetration in the global population but also promoted nontraditional usage of smartphones as point-of-care medical diagnostic devices, sensors, and portable digital microscopes. This paper reveals a simple, rapid, cost-effective, and template-free technique for mass-scale production of an elastomeric PDMS (ePDMS) planoconvex lens capable of converting a smartphone into a portable digital microscope. By taking advantage of the resistance to spreading of liquid by a sharp edge, highly stable spherical cap of viscous liquid PDMS (lPDMS) on a smooth PMMA circular disk was fabricated. The axisymmetric spreading of lPDMS under the gravitational force and interfacial tension force enable the formation of spherical cap with a certain radius of curvature. A thermal treatment at 80 °C for 30 min cured the spherical cap lPDMS into a bubble-free ePDMS planoconvex lens. Lenses with focal lengths of 55.2-3.4 mm could be reproducibly fabricated by adjusting the volume of dispensed lPDMSs and diameter of PMMA disks. High-resolution panoramic microscope images without a distortion of small cylindrical object could be constructed on-the-fly using the imbedded smartphone app. Applications of the smartphone digital microscope equipped with an ePDMS planoconvex lens for imaging of micro printings, gun shot residues, cylindrical objects, and bullet toolmarks were explored. PMID:27419266

  18. Nitration by a simulated fuel technique for nitride fuel re-fabrication

    NASA Astrophysics Data System (ADS)

    Lee, Young.-Woo; Ryu, Ho Jin; Lee, Jae Won; Lee, Jung Won; Park, Geun Il

    2009-07-01

    Nitration reaction of a spent nuclear oxide fuel through a carbothermic reduction and the change in thermal conductivity of the resultant nitride specimens were investigated by a simulated fuel technique for use in nitride fuel re-fabrication from spent oxide fuel. The simulated spent oxide fuel was formed by compacting and sintering a powder mixture of UO 2 and stable oxide fission product impurities. It was pulverized by a 3-cycle successive oxidation-reduction treatment and converted into nitride pellet specimens through the carbothermic reduction. The rate of the nitration reaction of the simulated spent oxide fuel was decreased due to the fission product impurities when compared with pure uranium dioxide. The amount of Ba and Sr in the simulated spent oxide fuel was considerably reduced after the nitride fuel re-fabrication. The thermal conductivity of the nitride pellet specimen in the range 295-373 K was lower than that of the pure uranium nitride but higher than the simulated spent oxide fuel containing fission product impurities.

  19. A technique for fabricating single screw-retained implant-supported interim crowns in conjunction with implant surgery.

    PubMed

    McRory, M Eric; Cagna, David R

    2014-06-01

    This article presents an intraoral technique for fabricating single screw-retained implant-supported interim crowns immediately after surgical implant placement in extraction sites. The technique may be used with any implant system that provides a provisional abutment or an open-tray impression coping that can be modified for use as a provisional abutment. PMID:24461941

  20. Bonding techniques for the fabrication of internally cooled x-ray monochromators

    SciTech Connect

    Smolenski, K.W.; Conolly, C.; Doing, P.; Kiang, B.; Shen, Q.

    1996-12-31

    At CHESS, 2,500 W total are absorbed by the first crystal of the double bounce monochromators located on the A2 and F2 wiggler beamlines. In order to dissipate this absorbed power and deliver the highest X-ray flux to an end station, the authors have explored the technique of internally cooling the silicon first crystals with water channels. This technique brings with it the need for reliable mechanical joints between the silicon diffracting surface and a glass or silicon water manifold. The joint must have structural strength to resist the internal water pressure and the cyclic heat load, be vacuum leak tight for operation in UHV, and not act as a source of residual strain in the crystal lattice of the diffracting surface. The authors have explored four bonding techniques which have been tested for their suitability to monochromator fabrication: direct silicon to silicon bonding, anodic glass to silicon bonding, a variety of ceramic and die attach adhesives (alumina, zirconia, silica/silver) and metallic diffusion bonding/brazing. In this paper, they characterize each method with respect to the requirements of structural integrity (bond tensile strength), residual strain (minimal effect on diffraction quality) and vacuum compatibility.

  1. Zinc Oxide Thin Films Fabricated with Direct Current Magnetron Sputtering Deposition Technique

    SciTech Connect

    Hoon, Jian-Wei; Chan, Kah-Yoong; Krishnasamy, Jegenathan; Tou, Teck-Yong

    2011-03-30

    Zinc oxide (ZnO) is a very promising material for emerging large area electronic applications including thin-film sensors, transistors and solar cells. We fabricated ZnO thin films by employing direct current (DC) magnetron sputtering deposition technique. ZnO films with different thicknesses ranging from 100 nm to 1020 nm were deposited on silicon (Si) substrate. The deposition pressure was varied from 12 mTorr to 25 mTorr. The influences of the film thickness and the deposition pressure on structural properties of the ZnO films were investigated using Mahr surface profilometer and atomic force microscopy (AFM). The experimental results reveal that the film thickness and the deposition pressure play significant role in the structural formation of the deposited ZnO thin films. ZnO films deposited on Si substrates are promising for variety of thin-film sensor applications.

  2. New fabrication technique for highly sensitive qPlus sensor with well-defined spring constant.

    PubMed

    Labidi, Hatem; Kupsta, Martin; Huff, Taleana; Salomons, Mark; Vick, Douglas; Taucer, Marco; Pitters, Jason; Wolkow, Robert A

    2015-11-01

    A new technique for the fabrication of highly sensitive qPlus sensor for atomic force microscopy (AFM) is described. The focused ion beam was used to cut then weld onto a bare quartz tuning fork a sharp micro-tip from an electrochemically etched tungsten wire. The resulting qPlus sensor exhibits high resonance frequency and quality factor allowing increased force gradient sensitivity. Its spring constant can be determined precisely which allows accurate quantitative AFM measurements. The sensor is shown to be very stable and could undergo usual UHV tip cleaning including e-beam and field evaporation as well as in situ STM tip treatment. Preliminary results with STM and AFM atomic resolution imaging at 4.5 K of the silicon Si(111)-7×7 surface are presented. PMID:26117434

  3. Fabrication of Nano-Composite Surface Layers on Aluminium Employing Friction Stir Processing Technique

    NASA Astrophysics Data System (ADS)

    Bozorg, S. F. K.; Zarghani, A. S.; Zarei-Hanzaki, A.

    2010-03-01

    Al/Al2O3 nano-composite surface layer was fabricated via friction stir processing technique. Commercial AA6082 aluminium alloy extruded bar and nanometric Al2O3 powder were subjected to friction stir processing at a substrate travel speed of 80 mm/min and a tool rotation speed of 1000 rpm using a hardened H-13 tool steel. The grain structure and reinforcement particles were investigated by using optical and scanning electron microscopy. Results show that Al2O3 particles can be more uniformly dispread in aluminium substrate by increasing the number of processing passes. Also, hardness enhancement of the nano-composite surface layer was found. This is attributed to uniform dispersion of Al2O3 particles.

  4. Fabrication of Nano-Composite Surface Layers on Aluminium Employing Friction Stir Processing Technique

    SciTech Connect

    Bozorg, S. F. K.; Zarghani, A. S.; Zarei-Hanzaki, A.

    2010-03-11

    Al/Al{sub 2}O{sub 3} nano-composite surface layer was fabricated via friction stir processing technique. Commercial AA6082 aluminium alloy extruded bar and nanometric Al{sub 2}O{sub 3} powder were subjected to friction stir processing at a substrate travel speed of 80 mm/min and a tool rotation speed of 1000 rpm using a hardened H-13 tool steel. The grain structure and reinforcement particles were investigated by using optical and scanning electron microscopy. Results show that Al{sub 2}O{sub 3} particles can be more uniformly dispread in aluminium substrate by increasing the number of processing passes. Also, hardness enhancement of the nano-composite surface layer was found. This is attributed to uniform dispersion of Al{sub 2}O{sub 3} particles.

  5. Process for fabricating polycrystalline semiconductor thin-film solar cells, and cells produced thereby

    DOEpatents

    Wu, Xuanzhi; Sheldon, Peter

    2000-01-01

    A novel, simplified method for fabricating a thin-film semiconductor heterojunction photovoltaic device includes initial steps of depositing a layer of cadmium stannate and a layer of zinc stannate on a transparent substrate, both by radio frequency sputtering at ambient temperature, followed by the depositing of dissimilar layers of semiconductors such as cadmium sulfide and cadmium telluride, and heat treatment to convert the cadmium stannate to a substantially single-phase material of a spinel crystal structure. Preferably, the cadmium sulfide layer is also deposited by radio frequency sputtering at ambient temperature, and the cadmium telluride layer is deposited by close space sublimation at an elevated temperature effective to convert the amorphous cadmium stannate to the polycrystalline cadmium stannate with single-phase spinel structure.

  6. Nanoscale electrode arrays produced with microscale lithographic techniques for use in biomedical sensing applications.

    PubMed

    Terry, Jonathan G; Schmüser, Ilka; Underwood, Ian; Corrigan, Damion K; Freeman, Neville J; Bunting, Andrew S; Mount, Andrew R; Walton, Anthony J

    2013-12-01

    A novel technique for the production of nanoscale electrode arrays that uses standard microfabrication processes and micron-scale photolithography is reported here in detail. These microsquare nanoband edge electrode (MNEE) arrays have been fabricated with highly reproducible control of the key array dimensions, including the size and pitch of the individual elements and, most importantly, the width of the nanoband electrodes. The definition of lateral features to nanoscale dimensions typically requires expensive patterning techniques that are complex and low-throughput. However, the fabrication methodology used here relies on the fact that vertical dimensions (i.e. layer thicknesses) have long been manufacturable at the nanoscale using thin film deposition techniques that are well established in mainstream microelectronics. The authors report for the first time two aspects that highlight the particular suitability of these MNEE array systems for probe monolayer biosensing. The first is simulation, which shows the enhanced sensitivity to the redox reaction of the solution redox couple. The second is the enhancement of probe film functionalisation observed for the probe film model molecule, 6-mercapto-1-hexanol compared with microsquare electrodes. Such surface modification for specific probe layer biosensing and detection is of significance for a wide range of biomedical and other sensing and analytical applications. PMID:24206769

  7. Chemical Fabrication Used to Produce Thin-Film Materials for High Power-to- Weight-Ratio Space Photovoltaic Arrays

    NASA Technical Reports Server (NTRS)

    Hepp, Aloysius F.; Rybicki, George C.; Raffaelle, Ryne P.; Harris, Jerry D.; Hehemann, David G.; Junek, William; Gorse, Joseph; Thompson, Tracy L.; Hollingsworth, Jennifer A.; Buhro, William E.

    2000-01-01

    The key to achieving high specific power (watts per kilogram) space solar arrays is the development of a high-efficiency, thin-film solar cell that can be fabricated directly on a flexible, lightweight, space-qualified durable substrate such as Kapton (DuPont) or other polyimide or suitable polymer film. Cell efficiencies approaching 20 percent at AM0 (air mass zero) are required. Current thin-film cell fabrication approaches are limited by either (1) the ultimate efficiency that can be achieved with the device material and structure or (2) the requirement for high-temperature deposition processes that are incompatible with all presently known flexible polyimide or other polymer substrate materials. Cell fabrication processes must be developed that will produce high-efficiency cells at temperatures below 400 degrees Celsius, and preferably below 300 degress Celsius to minimize the problems associated with the difference between the coefficients of thermal expansion of the substrate and thin-film solar cell and/or the decomposition of the substrate.

  8. Quantification of Changes in Mulberry Silk Fabrics due to Different Laundering: Using WAXS Technique

    NASA Astrophysics Data System (ADS)

    Parameswara, P.; Nivedita, S.; Somashekar, R.

    2011-07-01

    Loom finished mulberry silk fabrics (Taffeta) were machine laundered and hand laundered several times. X-ray diffractograms of pure and laundered fabrics were used to calculate microstructural parameters like average crystallite size (D) and lattice strain (Vegr) employing Williamson-Hall plot. Microstructural parameters were compared with measured mechanical properties like breaking load, tenacity, and elongation of warp yarns unraveled from fabrics. Surface morphology and texture of silk fabrics changed upon washing is evident from SEM images.

  9. Applications of Semiconductor Fabrication Methods to Nanomedicine: A Review of Recent Inventions and Techniques

    PubMed Central

    Rajasekhar, Achanta; Gimi, Barjor; Hu, Walter

    2013-01-01

    We live in a world of convergence where scientific techniques from a variety of seemingly disparate fields are being applied cohesively to the study and solution of biomedical problems. For instance, the semiconductor processing field has been primarily developed to cater to the needs of the ever decreasing transistor size and cost while increasing functionality of electronic circuits. In recent years, pioneers in this field have equipped themselves with a powerful understanding of how the same techniques can be applied in the biomedical field to develop new and efficient systems for the diagnosis, analysis and treatment of various conditions in the human body. In this paper, we review the major inventions and experimental methods which have been developed for nano/micro fluidic channels, nanoparticles fabricated by top-down methods, and in-vivo nanoporous microcages for effective drug delivery. This paper focuses on the information contained in patents as well as the corresponding technical publications. The goal of the paper is to help emerging scientists understand and improvise over these inventions. PMID:24312161

  10. Fabrication of uniformly cell-laden porous scaffolds using a gas-in-liquid templating technique.

    PubMed

    Takei, Takayuki; Aokawa, Ryuta; Shigemitsu, Takamasa; Kawakami, Koei; Yoshida, Masahiro

    2015-11-01

    Design of porous scaffolds in tissue engineering field was challenging. Uniform immobilization of cells in the scaffolds with high porosity was essential for homogeneous tissue formation. The present study was aimed at fabricating uniformly cell-laden porous scaffolds with porosity >74% using the gas-in-liquid foam templating technique. To this end, we used gelatin, microbial transglutaminase and argon gas as a scaffold material, cross-linker of the protein and porogen of scaffold, respectively. We confirmed that a porosity of >74% could be achieved by increasing the gas volume delivered to a gelatin solution. Pore size in the scaffold could be controlled by stirring speed, stirring time and the pore size of the filter through which the gas passed. The foaming technique enabled us to uniformly immobilize a human hepatoblastoma cell line in scaffold. Engraftment efficiency of the cell line entrapped within the scaffold in nude mice was higher than that of cells in free-form. These results showed that the uniformly cell-laden porous scaffolds were promising for tissue engineering. PMID:25912452

  11. Fabrication of nanostructure by physical vapor deposition with glancing angle deposition technique and its applications

    NASA Astrophysics Data System (ADS)

    Horprathum, M.; Eiamchai, P.; Kaewkhao, J.; Chananonnawathorn, C.; Patthanasettakul, V.; Limwichean, S.; Nuntawong, N.; Chindaudom, P.

    2014-09-01

    A nanostructural thin film is one of the highly exploiting research areas particularly in applications in sensor, photocatalytic, and solar-cell technologies. In the past two decades, the integration of glancing-angle deposition (GLAD) technique to physical vapor deposition (PVD) process has gained significant attention for well-controlled multidimensional nanomorphologies because of fast, simple, cost-effective, and mass-production capability. The performance and functional properties of the coated thin films generally depend upon their nanostructural compositions, i.e., large aspect ratio, controllable porosity, and shape. Such structural platforms make the fabricated thin films very practical for several realistic applications. We therefore present morphological and nanostructural properties of various deposited materials, which included metals, i.e., silver (Ag), and oxide compounds, i.e., tungsten oxide (WO3), titanium dioxide (TiO2), and indium tin oxide (ITO). Different PVD techniques based on DC magnetron sputtering and electron-beam evaporation, both with the integrated GLAD component, were discussed. We further explore engineered nanostructures which enable controls of optical, electrical, and mechanical properties. These improvements led to several practical applications in surface-enhanced Raman, smart windows, gas sensors, self-cleaning materials and transparent conductive oxides (TCO).

  12. Creating tissues from textiles: scalable nonwoven manufacturing techniques for fabrication of tissue engineering scaffolds.

    PubMed

    Tuin, S A; Pourdeyhimi, B; Loboa, E G

    2016-02-01

    Electrospun nonwovens have been used extensively for tissue engineering applications due to their inherent similarities with respect to fibre size and morphology to that of native extracellular matrix (ECM). However, fabrication of large scaffold constructs is time consuming, may require harsh organic solvents, and often results in mechanical properties inferior to the tissue being treated. In order to translate nonwoven based tissue engineering scaffold strategies to clinical use, a high throughput, repeatable, scalable, and economic manufacturing process is needed. We suggest that nonwoven industry standard high throughput manufacturing techniques (meltblowing, spunbond, and carding) can meet this need. In this study, meltblown, spunbond and carded poly(lactic acid) (PLA) nonwovens were evaluated as tissue engineering scaffolds using human adipose derived stem cells (hASC) and compared to electrospun nonwovens. Scaffolds were seeded with hASC and viability, proliferation, and differentiation were evaluated over the course of 3 weeks. We found that nonwovens manufactured via these industry standard, commercially relevant manufacturing techniques were capable of supporting hASC attachment, proliferation, and both adipogenic and osteogenic differentiation of hASC, making them promising candidates for commercialization and translation of nonwoven scaffold based tissue engineering strategies. PMID:26908485

  13. Fabrication of nanostructure by physical vapor deposition with glancing angle deposition technique and its applications

    SciTech Connect

    Horprathum, M. Eiamchai, P. Patthanasettakul, V.; Limwichean, S.; Nuntawong, N.; Chindaudom, P.; Kaewkhao, J.; Chananonnawathorn, C.

    2014-09-25

    A nanostructural thin film is one of the highly exploiting research areas particularly in applications in sensor, photocatalytic, and solar-cell technologies. In the past two decades, the integration of glancing-angle deposition (GLAD) technique to physical vapor deposition (PVD) process has gained significant attention for well-controlled multidimensional nanomorphologies because of fast, simple, cost-effective, and mass-production capability. The performance and functional properties of the coated thin films generally depend upon their nanostructural compositions, i.e., large aspect ratio, controllable porosity, and shape. Such structural platforms make the fabricated thin films very practical for several realistic applications. We therefore present morphological and nanostructural properties of various deposited materials, which included metals, i.e., silver (Ag), and oxide compounds, i.e., tungsten oxide (WO{sub 3}), titanium dioxide (TiO{sub 2}), and indium tin oxide (ITO). Different PVD techniques based on DC magnetron sputtering and electron-beam evaporation, both with the integrated GLAD component, were discussed. We further explore engineered nanostructures which enable controls of optical, electrical, and mechanical properties. These improvements led to several practical applications in surface-enhanced Raman, smart windows, gas sensors, self-cleaning materials and transparent conductive oxides (TCO)

  14. Fabrication of plastic microlens arrays for array microscopy by diamond milling techniques

    NASA Astrophysics Data System (ADS)

    McCall, Brian; Birch, Gabriel; Descour, Michael; Tkaczyk, Tomasz

    2010-02-01

    Six microlens arrays are fabricated in a single step process using diamond milling techniques, plunging and micromilling. Four of the lenses are cut using plunging, two each in poly(methyl methacrylate) and polystyrene (Rexolite 1422), and the other two are cut in polystyrene using 3D micro-milling. Half of the lenses are concave and the other half are convex. These are high power lenses having steep sag at the edges and radii between 2.0 - 2.1 mm for each array. The clear aperture diameters of the lenses are about 3.2 mm for plunged lenses and 2.6 mm for micro-milled lenses. The lenses are spaced 4 mm apart in a square grid. Setup and method of these techniques is described and the lens arrays are characterized based on radius (power) error, wavefront error, roughness, and grid position error. Micro-milled lenses are shown to be of high optical quality compared with standards for injection molded plastic lenses.

  15. Solid Dispersion Matrix Tablet Comprising Indomethacin-PEG-HPMC Fabricated with Fusion and Mold Technique.

    PubMed

    Mesnukul, A; Yodkhum, K; Phaechamud, T

    2009-07-01

    The purpose of this study is to fabricate the polyethylene glycol matrix tablet by mold technique. Indomethacin and hydroxypropylmethylcellulose were used as model drug and polymer, respectively, in PEG matrix system. The physical and drug release characteristics of developed matrix tablet were studied. This inert carrier system comprising 7:3 polyethylene glycol 4000: polyethylene glycol 400 could effectively enhance the solubility of indomethacin and an addition of hydroxypropylmethylcellulose could sustain the drug release. Scanning electron microscope photomicrograph indicated the drug diffusion outward through the porous network of this developed matrix tablet into the dissolution fluid. Least square fitting the experimental dissolution data to the mathematical expressions (power law, first-order, Higuchi's and zero-order) indicated the drug release kinetics primarily as Fickian diffusion. Both the enhancement of drug dissolution and the prolongation of the drug release could be achieved for aqueous insoluble drug such as, indomethacin, by using polyethylene glycol-hydroxypropylmethylcellulose matrix system prepared with melting and mold technique. PMID:20502547

  16. A novel wet extrusion technique to fabricate self-assembled microfiber scaffolds for controlled drug delivery.

    PubMed

    Lavin, Danya M; Harrison, Michael W; Tee, Louis Y; Wei, Karen A; Mathiowitz, Edith

    2012-10-01

    We have developed a novel wet extrusion process to fabricate nonwoven self-assembled microfiber scaffolds with uniform diameters less than 5 μm and without any postmanipulation. In this method, a poly(L-lactic acid) solution flows dropwise into a stirring nonsolvent bath, deforming into liquid polymer streams that self-assemble into a nonwoven microfiber scaffold. The ability to tune fiber diameter was achieved by decreasing polymer spin dope concentration and increasing the silicon oil to petroleum ether ratio of the nonsolvent spin bath. To demonstrate the drug delivery capabilities of scaffolds, heparin was encapsulated using a conventional water-in-oil (W/O) emulsion technique and a cryogenic emulsion technique developed in our laboratory. Spin dope preparation was found to significantly effect the release kinetics of self-assembled scaffolds by altering the interconnectivity of pores within the precipitating filaments. After 35 days, scaffolds prepared from W/O emulsions released up to 45% encapsulated heparin, whereas nearly 80% release of heparin was observed from cryogenic emulsion formulations. The versatility of our system, combined with the prolonged release of small molecules and the ability to control the homogeneity of self-assembling scaffolds, could be beneficial for many tissue regeneration and engineering applications. PMID:22623283

  17. Solid Dispersion Matrix Tablet Comprising Indomethacin-PEG-HPMC Fabricated with Fusion and Mold Technique

    PubMed Central

    Mesnukul, A.; Yodkhum, K.; Phaechamud, T.

    2009-01-01

    The purpose of this study is to fabricate the polyethylene glycol matrix tablet by mold technique. Indomethacin and hydroxypropylmethylcellulose were used as model drug and polymer, respectively, in PEG matrix system. The physical and drug release characteristics of developed matrix tablet were studied. This inert carrier system comprising 7:3 polyethylene glycol 4000: polyethylene glycol 400 could effectively enhance the solubility of indomethacin and an addition of hydroxypropylmethylcellulose could sustain the drug release. Scanning electron microscope photomicrograph indicated the drug diffusion outward through the porous network of this developed matrix tablet into the dissolution fluid. Least square fitting the experimental dissolution data to the mathematical expressions (power law, first-order, Higuchi's and zero-order) indicated the drug release kinetics primarily as Fickian diffusion. Both the enhancement of drug dissolution and the prolongation of the drug release could be achieved for aqueous insoluble drug such as, indomethacin, by using polyethylene glycol-hydroxypropylmethylcellulose matrix system prepared with melting and mold technique. PMID:20502547

  18. Comparison of three-dimensional printing and vacuum freeze-dried techniques for fabricating composite scaffolds.

    PubMed

    Sun, Kai; Li, Ruixin; Jiang, Wenxue; Sun, Yufu; Li, Hui

    2016-09-01

    In this study, the performances of different preparation methods of the scaffolds were analyzed for chondrocyte tissue engineering. Silk fibroin/collagen (SF/C) was fabricated using a vacuum freeze-dried technique and by 3D printing. The porosity, water absorption expansion rates, mechanical properties, and pore sizes of the resulting materials were evaluated. The proliferation and metabolism of the cells was detected at different time points using an MTT assay. Cell morphologies and distributions were observed by histological analysis and scanning electron microscopy (SEM). The porosity, water absorption expansion rate, and Young's modulus of the material obtained via 3D printing were significantly higher than those obtained by the freeze-dried method, while the pore size did not differ significantly between the two methods. MTT assay results showed that the metabolism of cells seeded on the 3D printed scaffolds was more viable than the metabolism on the freeze-dried material. H&E staining of the scaffolds revealed that the number of cells in the 3D printed scaffold was higher in comparison to a similar measurement on the freeze-dried material. Consequently, stem cells grew well inside the 3D printed scaffolds, as measured by SEM, while the internal structure of the freeze-dried scaffold was disordered. Compared with the freeze-dried technique, the 3D printed scaffold exhibited better overall performance and was more suitable for cartilage tissue engineering. PMID:27404126

  19. Development of Hot Pressing as a Low Cost Processing Technique for Fuel Cell Fabrication

    SciTech Connect

    Sarin, V

    2003-01-14

    Dependable, plentiful, and economical energy has been the driving force for financial, industrial, and political growth in the US since the mid 19th century. For a country whose progress is so deeply rooted in abundant energy and whose current political agenda involves stabilizing world fossil fuel prices, the development of a reliable, efficient and environmentally friendly power generating source seems compulsory. The maturing of high technology fuel cells may be the panacea the country will find indispensable to free itself from foreign dependence. Fuel cells offer an efficient, combustion-less, virtually pollution-free power source, capable of being sited in downtown urban areas or in remote regions. Fuel cells have few moving parts and run almost silently. Fuel cells are electrochemical devices that convert the chemical energy of a fuel directly to electrical energy. Unlike batteries, which store a finite amount of energy, fuel cells will generate electricity continuously, as long as fuel and oxidant are available to the electrodes. Additionally, fuel cells offer clean, efficient, and reliable power and they can be operated using a variety of fuels. Hence, the fuel cell is an extremely promising technology. Over the course of this research, the fundamental knowledge related to ceramic processing, sintering, and hot pressing to successfully hot press a single operational SOFC in one step has been developed. Ceramic powder processing for each of the components of an SOFC has bene tailored towards this goal. Processing parameter for the electrolyte and cathode have been studied and developed until they converted. Several anode fabrication techniques have been developed. Additionally, a novel anode structured has been developed and refined. These individual processes have been cultivated until a single cell SOFC has been fabricated in one step.

  20. Electrochemical Evaluation of Lead Base Composite Anodes Fabricated by Accumulative Roll Bonding Technique

    NASA Astrophysics Data System (ADS)

    Karbasi, Maryam; Keshavarz Alamdari, Eskandar

    2015-04-01

    Accumulative roll bonding is used for the first time in lead systems to fabricate advanced lead base composite anodes. For this purpose, Ag as the most common and effective additive, Co as the best metallic immiscible substitution for Ag, and MnO2 as the ceramic and electrocatalytic agent have been used as additives to produce anodes. The accumulative roll bonding processed sheets have been fabricated under determined conditions. The electrochemical properties of the prepared samples are investigated by Electrochemical Impedance Spectroscopy, Cyclic Voltammetry, Polarization tests, electrowinning tests, and Scanning Electron Microscopy. The results indicate that the ARB-processed composite lead sheets can be perfectly used as novel developed anodes. The advantages include 5.51 times increase of current density, in the Pb-pct0.5Ag 9-pass sample compared to pure lead anode, decreased charge transfer resistance from 56.31 (Ω cm2) in pure lead anode to 17.5 (Ω cm2) in the Pb-pct2MnO2 8-pass sample (72 pct lower), and decreased oxygen evolution potential from 1.95 (V/SHE) in pure lead anode to 1.77 (V/SHE) in the Pb-pct2MnO2 8-pass sample (0.18 (V/SHE) lower). Electrowinning tests results reveal Pb-2 pctMnO2 8-pass showed best anodic performance withsignificant lower compared corrosion rate (75 pct), product and electrolyte contamination, slime formation, energy consumption and higher Zn deposit and energy conservation (to 294 kWh/t-Zn). Finest Zn deposit morphology (effective reduced grain size corresponding to smoothness and compaction) has been supplied by Pb-2 pctMnO2 8-pass sample resulted from enhanced growth rate of Zn in lack of Pb contaminations that could act as suitable nucleation sites.

  1. An Alternate Vista in Rehabilitation of Cranial Defects: Combining Digital and Manual Techniques to Fabricate a Hybrid Cranioplast.

    PubMed

    Kaur, Harsimran; Nanda, Aditi; Koli, Dheeraj; Verma, Mahesh; Singh, Hukum; Bishnoi, Ishu; Pathak, Pooja; Gupta, Ankur

    2015-06-01

    The desired features of a cranioplast include providing an acceptable contour, continuity with the remaining skull (marginal adaptation), improvising the aesthetic outcome, providing a strengthened prosthesis to avoid fracture in case of repeat trauma, and protecting the remaining neurological structures. Combining digital and manual techniques to fabricate a hybrid polymethylmethacrylate cranioplast during the rehabilitation of a pediatric patient with cranial defect has been described. Utilization of digital techniques (rapid prototyping to obtain skull analog) and manual (hand) sculpting of the prosthesis strengthened with glass fiber enabled the authors to fabricate a hybrid cranioplast. Satisfactory outcome was achieved. PMID:26080183

  2. Application of powder metallurgy techniques to produce improved bearing elements for liquid rocket engines

    NASA Technical Reports Server (NTRS)

    Moracz, D. J.; Shipley, R. J.; Moxson, V. S.; Killman, R. J.; Munson, H. E.

    1992-01-01

    The objective was to apply powder metallurgy techniques for the production of improved bearing elements, specifically balls and races, for advanced cryogenic turbopump bearings. The materials and fabrication techniques evaluated were judged on the basis of their ability to improve fatigue life, wear resistance, and corrosion resistance of Space Shuttle Main Engine (SSME) propellant bearings over the currently used 440C. An extensive list of candidate bearing alloys in five different categories was considered: tool/die steels, through hardened stainless steels, cobalt-base alloys, and gear steels. Testing of alloys for final consideration included hardness, rolling contact fatigue, cross cylinder wear, elevated temperature wear, room and cryogenic fracture toughness, stress corrosion cracking, and five-ball (rolling-sliding element) testing. Results of the program indicated two alloys that showed promise for improved bearing elements. These alloys were MRC-2001 and X-405. 57mm bearings were fabricated from the MRC-2001 alloy for further actual hardware rig testing by NASA-MSFC.

  3. Microfluidic-based photocatalytic microreactor for environmental application: a review of fabrication substrates and techniques, and operating parameters.

    PubMed

    Das, Susmita; Srivastava, Vimal Chandra

    2016-06-01

    Photochemical technology with microfluidics is emerging as a new platform in environmental science. Microfluidic technology has various advantages, like better mixing and a shorter diffusion distance for the reactants and products; and uniform distribution of light on the photocatalyst. Depending on the material type and related applications, several fabrication techniques have been adopted by various researchers. Microreactors have been prepared by various techniques, such as lithography, etching, mechanical microcutting technology, etc. Lithography can be classified into photolithography, soft lithography and X-ray lithography techniques whereas the etching process is divided into wet etching (chemical etching) and dry etching (plasma etching) techniques. Several substrates, like polymers, such as polydimethyl-siloxane (PDMS), polymethyle-methacrylate (PMMA), hydrogel, etc.; metals, such as stainless steel, titanium foil, etc.; glass, such as silica capillary, glass slide, etc.; and ceramics have been used for microchannel fabrication. During degradation in a microreactor, the degradation efficiency is affected by few important parameters such as flow rate, initial concentration of the target compound, microreactor dimensions, light intensity, photocatalyst structure and catalyst support. The present paper discusses and critically reviews fabrication techniques and substrates used for microchannel fabrication and critical operating parameters for organics, especially dye degradation in the microreactor. The kinetics of degradation has also been discussed. PMID:27193741

  4. Development of nano-fabrication technique utilizing self-organizational behavior of point defects induced by ion irradiation

    NASA Astrophysics Data System (ADS)

    Nitta, Noriko; Taniwaki, Masafumi

    2006-04-01

    The present authors proposed a novel nano-fabrication technique that is able to arrange the fine cells orderly, based on their finding in GaSb implanted at a low temperature. In this article, first the experimental results that anomalous cellular structure was formed in GaSb by ion implantation is introduced and the self-organizational formation mechanism of the structure is described. Next a nano-fabrication technique that utilizes focused ion beam is described. This technique consists of two procedures, i.e. the formation process of the voids array and the development of the initial array to ordered cellular structure. Finally, the nano-fabrication is actually performed by this technique and their results are reported. Fabrication succeeded in structures where the dot (cell) interval was 100 nm or larger. The minimum ion dose for initial voids which develops to the ordered cellular structure is evaluated. It is also shown that the substrate temperature during implantation is an essential parameter for this technique.

  5. Novel Engineering and Fabrication Techniques Tested in Low-Noise- Research Fan Blades

    NASA Technical Reports Server (NTRS)

    Cunningham, Cameron C.

    2003-01-01

    A major source of fan noise in commercial turbofan engines is the interaction of the wake from the fan blades with the stationary vanes (stators) directly behind them. The Trailing Edge Blowing (TEB) project team at the NASA Glenn Research Center designed and fabricated new fan blades to study the effects of fan trailing edge blowing as a potential noise-reduction concept. The intent is to fill the rotor wake by supplying air to the rotor blade trailing edge at the proper conditions to minimize the wake deficit, and thus generate less noise. The TEB hardware is designed for the Active Noise Control Fan (ANCF) test rig in Glenn's Aeroacoustic Propulsion Laboratory. For this test, the air is fed from an external supply through the shaft of the rig. It is distributed to the base of each blade through an impeller, where it is forced into a plenum at the core of each blade. In actual engine configuration, air would most likely be bled from the compressor, but only at times when noise is an issue, such as takeoffs and landings. Glenn researchers designed and manufactured the blades in-house, using new techniques and concepts. The skins, which were designed for maximum strength in the directions of highest stress, were molded from multiple layers of carbon fiber. Considerable use was made of rapid prototyping techniques, such as laser sintering. The core was sintered from a lightweight polymer, and the retainer was CNC-machined (computer numerical control machined) from aluminum. All the components were joined with a cold-cure aerospace adhesive. These techniques and processes reduced the overall cost and allowed the new concept to be studied much sooner than would be possible using traditional fabrication methods. Since this test rig did not support the use of blade-monitoring techniques such as strain gauges, extensive bench testing was required to qualify the design. The blades were examined using a variety of methods including holography, pull tests (cyclic and

  6. Sample-inverted reflow technique for fabrication of a revolved-hyperboloid microlens array in hybrid solgel glass.

    PubMed

    He, Miao; Yuan, Xiaocong; Bu, Jing

    2004-09-01

    We propose a novel fabrication method, which is referred to as the sample-inverted reflow technique, to fabricate a refractive microlens array (MLA) with a revolved-hyperboloid profile in a solgel material. The fabricated solgel MLA demonstrates an excellent smooth profile with a fabrication error much less than the difference between the revolved hyperboloid and the spherical surface. In an application of coupling a laser diode (LD) to a single-mode fiber (SMF), we propose a two-MLA coupling scheme in which two revolved-hyperboloid MLAs are used between the LD and the SMF. In this configuration the coupling efficiency achieves 81.7% (-0.88 dB). PMID:15455761

  7. Michigan state upgrade to produce intense radioactive ion beams by fragmentation technique

    SciTech Connect

    Lubkin, G.B.

    1997-05-01

    This article describes the planned upgrading of accelerator facilities to produce intense radioactive ion beams, by a fragmentation technique, for experimental simulation of nucleosynthesis in novas and supernovas. (AIP) {ital 1997 American Institute of Physics.} {copyright} {ital 1997} {ital American Institute of Physics}

  8. Fabrication of concave refractive microlens arrays in solgel glass by a simple proximity-effect-assisted reflow technique.

    PubMed

    He, Miao; Yuan, Xiaocong; Bu, Jing; Cheong, Wai Chye

    2004-05-01

    We report a simple method for fabricating a concave refractive microlens array (MLA) in solgel glass by using a proximity-effect-assisted reflow technique. The solgel concave refractive MLA that we fabricated had excellent surface smoothness; good dimensional conformity, with an 8.23% nonuniformity of the microlens elements; and structural perfection, with a biggest deviation of 1% from a perfect concave spherical crown. The relative error between the measured and the designed values of the concave MLA's focal length was only 1.83%. Compared with the conventional fabrication techniques for concave MLAs, the proposed method has significant advantages including simplicity, low cost, good element conformity, and smooth device surface. PMID:15143656

  9. Comparison of Fabrication Techniques for Micro-Scale Spark Gap Plasma Switches

    NASA Astrophysics Data System (ADS)

    Burnette, Matthew; Staack, David

    2014-10-01

    Microplasma spark gaps with 2D geometries were fabricated by two techniques on alumina, first using photolithography and metal sputtering with thicknesses of hundreds of nanometers, and second using thermal-spray several microns thick, but with lower feature resolution. Several high temperature metals were tested as electrode material for the microplamsa device, including tungsten and chromium; however the chromium samples were not robust enough, eroding away too quickly for extensive testing. Scanning electron microscope (SEM) images were taken before and after testing to determine the wear on the samples. The sputtered tungsten thin films and thermal-spray deposited nickel films on alumina were compared after testing in 1 atm of helium running for one hour at a current of 1 mA. Slight wear and discoloration were noted on the anodes, yet significant erosion occurred on the cathodes; no wear was noted on the alumina. The thermally-sprayed nickel sample had the least wear, while the thin tungsten sample had the most wear. Discoloration was also seen on the nearby floating-voltage electrodes despite not being a part of the circuit, most likely due to heating. As the electrodes eroded, the plasma attachment point moved unpredictably. This work was supported in part by the Department of Defense Army Research Office under Grant W911NF1210007.

  10. Characterization and analysis of surface notches on Ti-alloy plates fabricated by additive manufacturing techniques

    NASA Astrophysics Data System (ADS)

    Chan, Kwai S.

    2015-12-01

    Rectangular plates of Ti-6Al-4V with extra low interstitial (ELI) were fabricated by layer-by-layer deposition techniques that included electron beam melting (EBM) and laser beam melting (LBM). The surface conditions of these plates were characterized using x-ray micro-computed tomography. The depth and radius of surface notch-like features on the LBM and EBM plates were measured from sectional images of individual virtual slices of the rectangular plates. The stress concentration factors of individual surface notches were computed and analyzed statistically to determine the appropriate distributions for the notch depth, notch radius, and stress concentration factor. These results were correlated with the fatigue life of the Ti-6Al-4V ELI alloys from an earlier investigation. A surface notch analysis was performed to assess the debit in the fatigue strength due to the surface notches. The assessment revealed that the fatigue lives of the additively manufactured plates with rough surface topographies and notch-like features are dominated by the fatigue crack growth of large cracks for both the LBM and EBM materials. The fatigue strength reduction due to the surface notches can be as large as 60%-75%. It is concluded that for better fatigue performance, the surface notches on EBM and LBM materials need to be removed by machining and the surface roughness be improved to a surface finish of about 1 μm.

  11. Fabrication of YSZ buffer layer by single source MOCVD technique for YBCO coated conductor

    NASA Astrophysics Data System (ADS)

    Jun, Byung-Hyuk; Sun, Jong-Won; Kim, Ho-Jin; Lee, Dong-Wook; Jung, Choong-Hwan; Park, Soon-Dong; Kim, Chan-Joong

    2003-10-01

    Yttria stabilized zirconia (YSZ) buffer layers were deposited by a metal organic chemical vapor deposition technique using a single liquid source for the application of YBa 2Cu 3O 7- δ (YBCO) coated conductor. Y:Zr mole ratio was 0.2:0.8, and tetrahydrofuran (THF) was used as a solvent. The (1 0 0) single crystal MgO substrate was used for searching the deposition conditions. Bi-axially oriented CeO 2 and NiO films were fabricated on {1 0 0} <0 0 1> textured Ni substrate by the same method and used as templates. At a constant working pressure of 10 Torr, the deposition temperatures (660-800 °C) and oxygen flow rates (100-500 sccm) were changed to find the optimum deposition condition. The best (1 0 0) oriented YSZ film on MgO was obtained at 740 °C and O 2 flow rate of 300 sccm. For a YSZ buffer layer with this deposition condition on a CeO 2/Ni template, full width half maximum values of the in-plane ( ϕ-scan) and out-of-plane ( ω-scan) alignments were 10.6° and 9.8°, respectively. The SEM image of YSZ film on CeO 2/Ni showed surface morphologies without microcracks. The film deposition rate was about 100 nm/min.

  12. Polyaniline-based organic memristive device fabricated by layer-by-layer deposition technique

    NASA Astrophysics Data System (ADS)

    Erokhina, Svetlana; Sorokin, Vladimir; Erokhin, Victor

    2015-09-01

    Memristors and memristive devices represent a splendid area of research due to the unique possibilities for the realization of new types of computer hardware elements and mimicking several essential properties of the nervous system of living beings. The organic memristive device was developed as an electronic single-device analogue of the synapse, suitable for the realization of circuits allowing Hebbian type of learning. This work is dedicated to the realization of the active channel of organic memristive devices by polyelectrolyte self-assembling (layer-by-layer technique). Stable and reproducible electrical characteristics of the device were obtained when the thickness of the active channel was more than seven bilayers. The device revealed rectifying behaviour and the presence of hysteresis—important properties for the realization of neuromorphic systems with synapse-like properties of the individual elements. Compared to previously reported results on organic memristive devices fabricated using other methods, the present device does not require any additional doping that is usually performed through acid treatment. Such a behaviour is extremely important for the cases in which biological systems (nervous cells, slime mould, etc.) must be interfaced with the system of organic memristive devices, since acid treatment can kill living beings. [Figure not available: see fulltext.

  13. Paper-based microfluidics: fabrication technique and dynamics of capillary-driven surface flow.

    PubMed

    Songok, Joel; Tuominen, Mikko; Teisala, Hannu; Haapanen, Janne; Mäkelä, Jyrki; Kuusipalo, Jurkka; Toivakka, Martti

    2014-11-26

    Paper-based devices provide an alternative technology for simple, low-cost, portable, and disposable diagnostic tools for many applications, including clinical diagnosis, food quality control, and environmental monitoring. In this study we report a two-step fabrication process for creating two-dimensional microfluidic channels to move liquids on a hydrophobized paper surface. A highly hydrophobic surface was created on paper by TiO2 nanoparticle coating using a high-speed, roll-to-roll liquid flame spray technique. The hydrophilic pattern was then generated by UV irradiation through a photomask utilizing the photocatalytic property of TiO2. The flow dynamics of five model liquids with differing surface tensions 48-72 mN·m(-1) and viscosities 1-15 mN·m(-2) was studied. The results show that the liquid front (l) in a channel advances in time (t) according to the power law l=Zt0.5 (Z is an empirical constant which depend on the liquid properties and channel dimensions). The flow dynamics of the liquids with low viscosity show a dependence on the channel width and the droplet volume, while the flow of liquids with high viscosity is mainly controlled by the viscous forces. PMID:25336235

  14. High-Quality Large-Magnification Polymer Lens from Needle Moving Technique and Thermal Assisted Moldless Fabrication Process.

    PubMed

    Amarit, Ratthasart; Kopwitthaya, Atcha; Pongsoon, Prasit; Jarujareet, Ungkarn; Chaitavon, Kosom; Porntheeraphat, Supanit; Sumriddetchkajorn, Sarun; Koanantakool, Thaweesak

    2016-01-01

    The need of mobile microscope is escalating as well as the demand of high quality optical components in low price. We report here a novel needle moving technique to fabricate milli-size lens together with thermal assist moldless method. Our proposed protocol is able to create a high tensile strength structure of the lens and its base which is beneficial for exploiting in convertinga smart phone to be a digital microscope. We observe that no bubble trapped in a lens when this technique is performed which can overcome a challenge problem found in a typical dropping technique. We demonstrate the symmetry, smoothness and micron-scale resolution of the fabricated structure. This proposed technique is promising to serve as high quality control mass production without any expensive equipment required. PMID:26765524

  15. High-Quality Large-Magnification Polymer Lens from Needle Moving Technique and Thermal Assisted Moldless Fabrication Process

    PubMed Central

    Pongsoon, Prasit; Jarujareet, Ungkarn; Chaitavon, Kosom; Porntheeraphat, Supanit; Sumriddetchkajorn, Sarun; Koanantakool, Thaweesak

    2016-01-01

    The need of mobile microscope is escalating as well as the demand of high quality optical components in low price. We report here a novel needle moving technique to fabricate milli-size lens together with thermal assist moldless method. Our proposed protocol is able to create a high tensile strength structure of the lens and its base which is beneficial for exploiting in convertinga smart phone to be a digital microscope. We observe that no bubble trapped in a lens when this technique is performed which can overcome a challenge problem found in a typical dropping technique. We demonstrate the symmetry, smoothness and micron-scale resolution of the fabricated structure. This proposed technique is promising to serve as high quality control mass production without any expensive equipment required. PMID:26765524

  16. Validity of content-based techniques to distinguish true and fabricated statements: A meta-analysis.

    PubMed

    Oberlader, Verena A; Naefgen, Christoph; Koppehele-Gossel, Judith; Quinten, Laura; Banse, Rainer; Schmidt, Alexander F

    2016-08-01

    Within the scope of judicial decisions, approaches to distinguish between true and fabricated statements have been of particular importance since ancient times. Although methods focusing on "prototypical" deceptive behavior (e.g., psychophysiological phenomena, nonverbal cues) have largely been rejected with regard to validity, content-based techniques constitute a promising approach and are well established within the applied forensic context. The basic idea of this approach is that experience-based and nonexperience-based statements differ in their content-related quality. In order to test the validity of the most prominent content-based techniques, criteria-based content analysis (CBCA) and reality monitoring (RM), we conducted a comprehensive meta-analysis on English- and German-language studies. Based on a variety of decision criteria, 56 studies were included revealing an overall effect size of g = 1.03 (95% confidence interval [0.78, 1.27], Q = 420.06, p < .001, I2 = 92.48%, N = 3,429). There was no significant difference in the effectiveness of CBCA and RM. Additionally, we investigated a number of moderator variables, such as characteristics of participants, statements, and judgment procedures, as well as general study characteristics. Results showed that the application of all CBCA criteria outperformed any incomplete CBCA criteria set. Furthermore, statement classification based on discriminant functions revealed higher discrimination rates than decisions based on sum scores. Finally, unpublished studies showed higher effect sizes than studies published in peer-reviewed journals. All results are discussed in terms of their significance for future research (e.g., developing standardized decision rules) and practical application (e.g., user training, applying complete criteria set). (PsycINFO Database Record PMID:27149290

  17. Fabrication of multi-layer polymeric micro-sieve having narrow slot pores with conventional ultraviolet-lithography and micro-fabrication techniques

    PubMed Central

    Ebrahimi Warkiani, Majid; Lou, Chao-Ping; Gong, Hai-Qing

    2011-01-01

    Fast detection of waterborne pathogens is important for securing the hygiene of drinking water. Detection of pathogens in water at low concentrations and minute quantities demands rapid and efficient enrichment methods in order to improve the signal-to-noise ratio of bio-sensors. We propose and demonstrate a low cost and rapid method to fabricate a multi-layer polymeric micro-sieve using conventional lithography techniques. The micro-fabricated micro-sieves are made of several layers of SU-8 photoresist using multiple coating and exposure steps and a single developing process. The obtained micro-sieves have good mechanical properties, smooth surfaces, high porosity (≈40%), and narrow pore size distribution (coefficient of variation < 3.33%). Sample loading and back-flushing using the multi-layer micro-sieve resulted in more than 90% recovery of pathogens, which showed improved performance than current commercial filters. PMID:22662051

  18. Novel elastomeric fibrous networks produced from poly(xylitol sebacate)2:5 by core/shell electrospinning: fabrication and mechanical properties.

    PubMed

    Li, Yuan; Thouas, George A; Chen, Qizhi

    2014-12-01

    Fabrication of nonlinear elastic materials that resemble biological tissues remains a challenge in biomaterials research. Here, a new fabrication protocol to produce elastomeric fibrous scaffolds was established, using the core/shell electrospinning technique. A prepolymer of poly(xylitol sebacate) with a 2:5mol ratio of xylitol:sebacic acid (PXS2:5) was first formulated, then co-electrospun with polyvinyl alcohol (PVA - 95,000Mw). After cross-linking of core polymer PXS2:5, the PVA shells were rinsed off in water, leaving a porous elastomeric network of PXS2:5 fibres. Under aqueous conditions, the PXS2:5 fibrous scaffolds exhibited stable, nonlinear J-shaped stress-strain curves, with large average rupture elongation (76%) and Young׳s modulus (~1.0MPa), which were in the range of muscle tissue. Rupture elongation of PXS2:5 was also much higher when electrospun, compared to 2D solid sheets (45%). In direct contact with cell monolayers under physiological conditions, PXS2:5 scaffolds were as biocompatible as those made of poly-l-lactic acid (PLLA), with improvements over culture medium alone. In conclusion, the newly developed porous PXS2:5 scaffolds show tissue-like mechanical properties and excellent biocompatibility, making them very promising for bioengineering of soft tissues and organs. PMID:25243671

  19. Comparison of obturator prosthesis fabricated using different techniques and its effect on the management of a hemipalatomaxillectomy patient

    PubMed Central

    Badadare, Mokshada M; Patil, Sanjayagouda B; Bhat, Sudhakara; Tambe, Abhijit

    2014-01-01

    Odontogenic tumours involving the maxilla or mandible are usually treated with surgical resection. To prevent recurrence, extensive surgical intervention might be carried out leaving the patient with anatomical defects. However, rehabilitation of such patients with an obturator can improve function, facial form and social acceptance. In this case, we have evaluated the different designs and techniques of fabrication of an obturator prosthesis used for the rehabilitation of a hemipalatomaxillectomy patient. A 40-year-old man presented with a loose fitting obturator prosthesis. He had undergone hemipalatomaxillectomy for the treatment of an ameloblastoma 2 years earlier and had been using an obturator prosthesis since then. Hollow-bulb obturator prostheses were fabricated using two different methods, the lost salt and open lid techniques. The obturator prosthesis fabricated with the lost salt technique weighed less than the patient's old obturator. But the obturator fabricated using the open lid technique did not only considerably reduce the weight of the prosthesis but also improved health, function, aesthetics, phonetics and quality of life in this hemipalatomaxillectomy patient. PMID:25188927

  20. Comparison of obturator prosthesis fabricated using different techniques and its effect on the management of a hemipalatomaxillectomy patient.

    PubMed

    Badadare, Mokshada M; Patil, Sanjayagouda B; Bhat, Sudhakara; Tambe, Abhijit

    2014-01-01

    Odontogenic tumours involving the maxilla or mandible are usually treated with surgical resection. To prevent recurrence, extensive surgical intervention might be carried out leaving the patient with anatomical defects. However, rehabilitation of such patients with an obturator can improve function, facial form and social acceptance. In this case, we have evaluated the different designs and techniques of fabrication of an obturator prosthesis used for the rehabilitation of a hemipalatomaxillectomy patient. A 40-year-old man presented with a loose fitting obturator prosthesis. He had undergone hemipalatomaxillectomy for the treatment of an ameloblastoma 2 years earlier and had been using an obturator prosthesis since then. Hollow-bulb obturator prostheses were fabricated using two different methods, the lost salt and open lid techniques. The obturator prosthesis fabricated with the lost salt technique weighed less than the patient's old obturator. But the obturator fabricated using the open lid technique did not only considerably reduce the weight of the prosthesis but also improved health, function, aesthetics, phonetics and quality of life in this hemipalatomaxillectomy patient. PMID:25188927

  1. Micropen direct-write technique for fabrication of advanced electroceramic and optical materials

    NASA Astrophysics Data System (ADS)

    Sun, Jingjing

    Direct-write technologies, a subset of the rapid prototyping, have been applied for many applications including electronics, photonics and biomedical engineering. Among them, Micropen(TM) is a promising technique, providing precision deposition of materials with various viscosities, on-line design changes and writing on nonplanar substrates. The objective of this project was to directly write two- and three-dimensional novel structures by Micropen(TM) for potential optical and transducer applications. First, to gain a basic understanding of Micropen(TM) operation, poly(methyl methacrylate) (PMMA) solutions were developed as a model system. The effects of solution rheological properties on deposition conditions were investigated. Secondly, PMMA/SiO2 hybrids were developed using sol-gel process. The effects of organic/inorganic ratios on thermal stability, microstructure and optical properties were studied. The solution with 80 wt% PMMA loading was chosen to deposit lines for optical applications. Another application was the direct-write of lead zirconate titanate (PZT) thick films (6-70 mum) for MEMS or high frequency medical imaging applications. Pastes consisting of 15-30 vol% ceramic loading in a sol-gel solution were prepared for the deposition of films on various substrates. The PZT sol was used as a binder as well as to achieve low temperature heat treatment of the films. Using the 15 vol% paste with a 250-mum pen tip, a four-layer film was deposited on a silicon substrate. This 16-mum film with 1 cm 2 area had K of 870, tandelta of 4.1%, Pr of 12.2 muC/cm 2 and Ec of 27 kV/cm. Furthermore, Micropen(TM) was utilized for the direct-write of ceramic skeletal structures to develop PZT ceramic/polymer composites with 2-2 connectivity for medical ultrasound transducers. Ceramic/binder based pastes were developed as writing materials. The 35 vol% paste exhibited shear thinning with a viscosity of 45 Pa˙s at lower shear rate and 3 Pa˙s at higher shear rate. Using a

  2. Fabrication of porous titanium scaffolds by stack sintering of microporous titanium spheres produced with centrifugal granulation technology.

    PubMed

    Chen, Hongjie; Wang, Chunli; Zhu, Xiangdong; Zhang, Kai; Fan, Yujiang; Zhang, Xingdong

    2014-10-01

    Microporosity plays a key role in bioactivity and osteoinductivity of a biomaterial scaffold. A simple new approach to fabricating load-bearing porous titanium (Ti) scaffolds with uniform porous structure, highly controllable pore size and excellent biocompatibility was developed in the present study. This method was based on stack sintering of microporous Ti spheres produced with centrifugal granulation of commercial Ti powders. Macropores (180.0-341.8 μm) and micropores (6.1-11.8 μm) of the scaffolds were dependent on the sizes of the Ti spheres and the Ti powders, respectively. The compressive strength of the scaffolds (83.4-108.9 MPa) was high enough for the repair of load-bearing bone defects. Besides, the abundant micropores occurred on the rough and convex surface of the Ti spheres in the scaffolds were more favorable for adsorption of serum proteins, and thus promoted the growth of mesenchymal stem cells (MSCs). PMID:25175203

  3. Ho:YAG transparent ceramics based on nanopowders produced by laser ablation method: Fabrication, optical properties, and laser performance

    NASA Astrophysics Data System (ADS)

    Bagayev, S. N.; Osipov, V. V.; Vatnik, S. M.; Shitov, V. A.; Vedin, I. A.; Platonov, V. V.; Steinberg, I. Sh.; Maksimov, R. N.

    2015-12-01

    We fabricate Ho:YAG transparent ceramics based on nanopowders produced by laser ablation method via two approaches. Higher transmittance (82% in the infrared region) is achieved in ceramics prepared with an additional round of pre-calcining before sintering. We evaluate the average volume of the scattering centers in the ceramics and their distribution along the sample depth by the direct count method using an optical microscope and by the novel method of collinear two-photon interband photoexcitation, respectively. The laser characteristics of the 1% Ho:YAG ceramics are investigated using an intracavity pumping scheme. The slope efficiency is ∼40% relative to the absorbed pumping power at 1.85 μm.

  4. Comparison the Marginal and Internal Fit of Metal Copings Cast from Wax Patterns Fabricated by CAD/CAM and Conventional Wax up Techniques

    PubMed Central

    Vojdani, M; Torabi, K; Farjood, E; Khaledi, AAR

    2013-01-01

    Statement of Problem: Metal-ceramic crowns are most commonly used as the complete coverage restorations in clinical daily use. Disadvantages of conventional hand-made wax-patterns introduce some alternative ways by means of CAD/CAM technologies. Purpose: This study compares the marginal and internal fit of copings cast from CAD/CAM and conventional fabricated wax-patterns. Materials and Method: Twenty-four standardized brass dies were prepared and randomly divided into 2 groups according to the wax-patterns fabrication method (CAD/CAM technique and conventional method) (n=12). All the wax-patterns were fabricated in a standard fashion by means of contour, thickness and internal relief (M1-M12: representative of CAD/CAM group, C1-C12: representative of conventional group). CAD/CAM milling machine (Cori TEC 340i; imes-icore GmbH, Eiterfeld, Germany) was used to fabricate the CAD/CAM group wax-patterns. The copings cast from 24 wax-patterns were cemented to the corresponding dies. For all the coping-die assemblies cross-sectional technique was used to evaluate the marginal and internal fit at 15 points. The Student’s t- test was used for statistical analysis (α=0.05). Results: The overall mean (SD) for absolute marginal discrepancy (AMD) was 254.46 (25.10) um for CAD/CAM group and 88.08(10.67) um for conventional group (control). The overall mean of internal gap total (IGT) was 110.77(5.92) um for CAD/CAM group and 76.90 (10.17) um for conventional group. The Student’s t-test revealed significant differences between 2 groups. Marginal and internal gaps were found to be significantly higher at all measured areas in CAD/CAM group than conventional group (p< 0.001). Conclusion: Within limitations of this study, conventional method of wax-pattern fabrication produced copings with significantly better marginal and internal fit than CAD/CAM (machine-milled) technique. All the factors for 2 groups were standardized except wax pattern fabrication technique, therefore

  5. Fit accuracy of metal partial removable dental prosthesis frameworks fabricated by traditional or light curing modeling material technique: An in vitro study

    PubMed Central

    Anan, Mohammad Tarek M.; Al-Saadi, Mohannad H.

    2015-01-01

    Objective The aim of this study was to compare the fit accuracies of metal partial removable dental prosthesis (PRDP) frameworks fabricated by the traditional technique (TT) or the light-curing modeling material technique (LCMT). Materials and methods A metal model of a Kennedy class III modification 1 mandibular dental arch with two edentulous spaces of different spans, short and long, was used for the study. Thirty identical working casts were used to produce 15 PRDP frameworks each by TT and by LCMT. Every framework was transferred to a metal master cast to measure the gap between the metal base of the framework and the crest of the alveolar ridge of the cast. Gaps were measured at three points on each side by a USB digital intraoral camera at ×16.5 magnification. Images were transferred to a graphics editing program. A single examiner performed all measurements. The two-tailed t-test was performed at the 5% significance level. Results The mean gap value was significantly smaller in the LCMT group compared to the TT group. The mean value of the short edentulous span was significantly smaller than that of the long edentulous span in the LCMT group, whereas the opposite result was obtained in the TT group. Conclusion Within the limitations of this study, it can be concluded that the fit of the LCMT-fabricated frameworks was better than the fit of the TT-fabricated frameworks. The framework fit can differ according to the span of the edentate ridge and the fabrication technique for the metal framework. PMID:26236129

  6. Fabrication of three-dimensional porous scaffolds with controlled filament orientation and large pore size via an improved E-jetting technique.

    PubMed

    Li, Jin Lan; Cai, Yan Li; Guo, Yi Lin; Fuh, Jerry Ying Hsi; Sun, Jie; Hong, Geok Soon; Lam, Ruey Na; Wong, Yoke San; Wang, Wilson; Tay, Bee Yen; Thian, Eng San

    2014-05-01

    Biodegradable polymeric scaffolds have been widely used in tissue engineering as a platform for cell proliferation and subsequent tissue regeneration. Conventional microextrusion methods for three-dimensional (3D) scaffold fabrication were limited by their low resolution. Electrospinning, a form of electrohydrodynamic (EHD) printing, is an attractive method due to its capability of fabricating high-resolution scaffolds at the nanometer/micrometer scale level. However, the scaffold was composed of randomly orientated filaments which could not guide the cells in a specific direction. Furthermore, the pores of the electrospun scaffold were small, thus preventing cell infiltration. In this study, an alternative EHD jet printing (E-jetting) technique has been developed and employed to fabricate 3D polycaprolactone (PCL) scaffolds with desired filament orientation and pore size. The effect of PCL solution concentration was evaluated. Results showed that solidified filaments were achieved at concentration >70% (w/v). Uniform filaments of diameter 20 μm were produced via the E-jetting technique, and X-ray diffraction and attenuated total reflectance Fourier transform infrared spectroscopic analyses revealed that there was no physicochemical changes toward PCL. Scaffold with a pore size of 450 μm and porosity level of 92%, was achieved. A preliminary in vitro study illustrated that live chondrocytes were attaching on the outer and inner surfaces of collagen-coated E-jetted PCL scaffolds. E-jetted scaffolds increased chondrocytes extracellular matrix secretion, and newly formed matrices from chondrocytes contributed significantly to the mechanical strength of the scaffolds. All these results suggested that E-jetting is an alternative scaffold fabrication technique, which has the capability to construct 3D scaffolds with aligned filaments and large pore sizes for tissue engineering applications. PMID:24155124

  7. Computer-Assisted Mandibular Reconstruction using a Patient-Specific Reconstruction Plate Fabricated with Computer-Aided Design and Manufacturing Techniques

    PubMed Central

    Wilde, Frank; Cornelius, Carl-Peter; Schramm, Alexander

    2014-01-01

    We investigated the workflow of computer-assisted mandibular reconstruction that was performed with a patient-specific mandibular reconstruction plate fabricated with computer-aided design and computer-aided manufacturing (CAD/CAM) techniques and a fibula flap. We assessed the feasibility of this technique from virtual planning to the completion of surgery. Computed tomography (CT) scans of a cadaveric skull and fibula were obtained for the virtual simulation of mandibular resection and reconstruction using ProPlan CMF software (Materialise®/DePuy Synthes®). The virtual model of the reconstructed mandible provided the basis for the computer-aided design of a patient-specific reconstruction plate that was milled from titanium using a five-axis milling machine and CAM techniques. CAD/CAM techniques were used for producing resection guides for mandibular resection and cutting guides for harvesting a fibula flap. Mandibular reconstruction was simulated in a cadaveric wet laboratory. No problems were encountered during the procedure. The plate was fixed accurately to the residual bone without difficulty. The fibula segments were attached to the plate rapidly and reliably. The fusion of preoperative and postoperative CT datasets demonstrated high reconstruction precision. Computer-assisted mandibular reconstruction with CAD/CAM-fabricated patient-specific reconstruction plates appears to be a promising approach for mandibular reconstruction. Clinical trials are required to determine whether these promising results can be translated into successful practice and what further developments are needed. PMID:25045420

  8. Computer-Assisted Mandibular Reconstruction using a Patient-Specific Reconstruction Plate Fabricated with Computer-Aided Design and Manufacturing Techniques.

    PubMed

    Wilde, Frank; Cornelius, Carl-Peter; Schramm, Alexander

    2014-06-01

    We investigated the workflow of computer-assisted mandibular reconstruction that was performed with a patient-specific mandibular reconstruction plate fabricated with computer-aided design and computer-aided manufacturing (CAD/CAM) techniques and a fibula flap. We assessed the feasibility of this technique from virtual planning to the completion of surgery. Computed tomography (CT) scans of a cadaveric skull and fibula were obtained for the virtual simulation of mandibular resection and reconstruction using ProPlan CMF software (Materialise(®)/DePuy Synthes(®)). The virtual model of the reconstructed mandible provided the basis for the computer-aided design of a patient-specific reconstruction plate that was milled from titanium using a five-axis milling machine and CAM techniques. CAD/CAM techniques were used for producing resection guides for mandibular resection and cutting guides for harvesting a fibula flap. Mandibular reconstruction was simulated in a cadaveric wet laboratory. No problems were encountered during the procedure. The plate was fixed accurately to the residual bone without difficulty. The fibula segments were attached to the plate rapidly and reliably. The fusion of preoperative and postoperative CT datasets demonstrated high reconstruction precision. Computer-assisted mandibular reconstruction with CAD/CAM-fabricated patient-specific reconstruction plates appears to be a promising approach for mandibular reconstruction. Clinical trials are required to determine whether these promising results can be translated into successful practice and what further developments are needed. PMID:25045420

  9. Fabrication of dual-pore scaffolds using SLUP (salt leaching using powder) and WNM (wire-network molding) techniques.

    PubMed

    Cho, Yong Sang; Hong, Myoung Wha; Kim, So-Youn; Lee, Seung-Jae; Lee, Jun Hee; Kim, Young Yul; Cho, Young-Sam

    2014-12-01

    In this study, a novel technique was proposed to fabricate dual-pore scaffolds combining both SLUP (salt leaching using powder) and WNM (wire-network molding) techniques. This technique has several advantages: solvent-free, no limit on the use of thermoplastic polymers as a raw material, and easiness of fabricating scaffolds with dual-scale pores that are interconnected randomized small pores. To fabricate dual-pore scaffolds, PCL and NaCl powders were mixed at a certain ratio. Subsequently, needles were inserted into a designed mold, and the mixture was filled into the mold thereafter. Subsequently, after the mold was pressurized, the mold was heated to melt the PCL powders. The PCL/NaCl structure and needles were separated from the mold. The structure was sonicated to leach-out the NaCl particles and was dried. Consequently, the remaining PCL structure became the dual-pore scaffold. To compare the characteristics of dual-pore scaffolds, control scaffolds, which are 3D plotter and SLUP scaffolds were fabricated. PMID:25491863

  10. Fabricating sub-collimating grids for an x-ray solar imaging spectrometer using LIGA techniques

    SciTech Connect

    Brennen, R.A.; Hecht, M.H.; Wiberg, D.V.

    1997-04-01

    The HESSI mission proposes to perform high resolution imaging and spectroscopy observations in the soft X-ray, hard X-ray, and gamma-ray regimes, with finer angular resolution (nearly 2 arcseconds) and finer energy resolution (approximately 1 keV) than has been previously possible. This combination of imaging and spectroscopy is achieved with a set of Rotating Modulation Collimators placed in front of an array of cooled germanium and silicon detectors. A set of 12 bi-grid collimators, each of which consists of a pair of identically pitched, widely-separated grids, is used to provide the imaging. Each grid consists of a planar array of equally-spaced, parallel, X-ray opaque slats separated by X-ray transparent slits. If the slits of each grid are parallel to each other and the pitch is identical for the two grids, then the transmission through the grid pair depends on the direction of incidence of the incoming X-rays. For slits and slats of equal width, the transmission varies between zero and 50% depending on whether the shadows of the slats in the top grid fall on the slits or slats of the lower grid. A complete transmission cycle from zero to 50% and back to zero corresponds to a change in source direction that is given by p/L, where L is the separation between the grids. The authors describe a deep etch lithography technique developed to fabricate the grids which have pitches below 100 {micro}m. They use a free standing sheet of PMMA as a base for the process, and use the ALS facility to perform the exposures of the PMMA.