Sample records for based cast films

  1. SPH based modelling of oxide and oxide film formation in gravity die castings

    NASA Astrophysics Data System (ADS)

    Ellingsen, K.; Coudert, T.; M'Hamdi, M.

    2015-06-01

    Gravity die casting is an important casting process which has the capability of making complicated, high-integrity components for e.g. the automotive industry. Oxides and oxide films formed during filling affect the cast product quality. The Smoothed particle hydrodynamics (SPH) method is particularly suited to follow complex flows. The SPH method has been used to study filling of a gravity die including the formation and transport of oxides and oxide films for two different filling velocities. A low inlet velocity leads to a higher amount of oxides and oxide films in the casting. The study demonstrates the usefulness of the SPH method for an increased understanding of the effect of different filling procedures on the cast quality.

  2. Melting and casting of FeAl-based cast alloy

    Microsoft Academic Search

    V. K. Sikka; D. Wilkening; J. Liebetrau; B. Mackey

    1998-01-01

    The FeAl-based intermetallic alloys are of great interest because of their low density, low raw material cost, and excellent resistance to high-temperature oxidation, sulfidation, carburization, and molten salts. The applications based on these unique properties of FeAl require methods to melt and cast these alloys into complex-shaped castings and centrifugal cast tubes. This paper addresses the melting-related issues and the

  3. Melting and casting of FeAl-based cast alloy

    SciTech Connect

    Sikka, V.K. [Oak Ridge National Lab., TN (United States); Wilkening, D. [Columbia Falls Aluminum Co., Columbia Falls, MT (United States); Liebetrau, J.; Mackey, B. [AFFCO, L.L.C., Anaconda, MT (United States)

    1998-11-01

    The FeAl-based intermetallic alloys are of great interest because of their low density, low raw material cost, and excellent resistance to high-temperature oxidation, sulfidation, carburization, and molten salts. The applications based on these unique properties of FeAl require methods to melt and cast these alloys into complex-shaped castings and centrifugal cast tubes. This paper addresses the melting-related issues and the effect of chemistry on the microstructure and hardness of castings. It is concluded that the use of the Exo-Melt{trademark} process for melting and the proper selection of the aluminum melt stock can result in porosity-free castings. The FeAl alloys can be melted and cast from the virgin and revert stock. A large variation in carbon content of the alloys is possible before the precipitation of graphite flakes occurs. Titanium is a very potent addition to refine the grain size of castings. A range of complex sand castings and two different sizes of centrifugal cast tubes of the alloy have already been cast.

  4. Land-based turbine casting initiative

    SciTech Connect

    Mueller, B.A.; Spicer, R.A. [Howmet Corp., Whitehall, MI (United States)

    1995-12-31

    To meet goals for the ATS program, technical advances developed for aircraft gas turbine engines need to be applied to land-based gas turbines. These advances include directionally solidified and single crystal castings, alloys tailored to exploit these microstructures, complex internal cooling schemes, and coatings. The proposed program to scale aircraft gas turbine casting technology up to land based gas turbine size components is based on low sulfur alloys, casting process development, post-cast process development, and establishing casting defect tolerance levels. The inspection side is also discussed.

  5. RELIABILITY-BASED CASTING PROCESS DESIGN OPTIMIZATION

    E-print Network

    Beckermann, Christoph

    RELIABILITY-BASED CASTING PROCESS DESIGN OPTIMIZATION Richard Hardin1 , K.K. Choi1 , and Christoph 52242-1527 Keywords: Casting Process Design, Optimization, Reliability-Based Design Optimization purpose reliability-based design optimization (RBDO) software tool previously developed at the University

  6. Chitosan-based electrospun nanofibrous mats, hydrogels and cast films: novel anti-bacterial wound dressing matrices.

    PubMed

    Shahzad, Sohail; Yar, Muhammad; Siddiqi, Saadat Anwar; Mahmood, Nasir; Rauf, Abdul; Qureshi, Zafar-ul-Ahsan; Anwar, Muhammad Sabieh; Afzaal, Shahida

    2015-03-01

    The development of highly efficient anti-bacterial wound dressings was carried out. For this purpose nanofibrous mats, hydrogels and films were synthesized from chitosan, poly(vinyl alcohol) and hydroxyapatite. The physical/chemical interactions of the synthesized materials were evaluated by FTIR. The morphology, structure; average diameter and pore size of the materials were investigated by scanning electron microscopy. The hydrogels showed a greater degree of swelling as compared to nanofibrous mats and films in phosphate buffer saline solution of pH 7.4. The in vitro drug release studies showed a burst release during the initial period of 4 h and then a sustained release profile was observed in the next upcoming 20 h. The lyophilized hydrogels showed a more slow release as compared to nanofibrous mats and films. Antibacterial potential of drug released solutions collected after 24 h of time interval was determined and all composite matrices showed good to moderate activity against Gram-positive and Gram-negative bacterial strains respectively. To determine the cytotoxicity, cell culture was performed for various cefixime loaded substrates by using neutral red dye uptake assay and all the matrices were found to be non-toxic. PMID:25716023

  7. Storage Stability and Antibacterial Activity against E. coli O157:H7 of Carvacrol in Edible Apple Films made by Two Different Casting Methods

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The antimicrobial activities against E. coli O157:H7, as well as the stability of carvacrol, the main constituent of oregano oil, were evaluated during the preparation and storage of apple-based edible films made by two different casting methods, continuous casting and batch casting. Antimicrobial ...

  8. The cast aluminum denture base. Part II: Technique.

    PubMed

    Halperin, A R; Halperin, G C

    1980-07-01

    A technique to wax-up and cast an aluminum base and a method to incorporate the base into the final denture base has been discussed. This technique does not use induction casting, rather it uses two casting ovens and a centrifugal casting machine. PMID:6991680

  9. Understanding how processing additives tune nanoscale morphology of high efficiency organic photovoltaic blends: From casting solution to spun-cast thin film

    SciTech Connect

    Shao, Ming [ORNL; Keum, Jong Kahk [ORNL; Kumar, Rajeev [ORNL; Chen, Jihua [ORNL; Browning, Jim [ORNL; Chen, Wei [Argonne National Laboratory (ANL); Jianhui, Hou [Chinese Academy of Sciences (CAS), Institute of Chemistry; Do, Changwoo [ORNL; Littrell, Ken [ORNL; Sanjib, Das [University of Tennessee, Knoxville (UTK); Rondinone, Adam Justin [ORNL; Geohegan, David B [ORNL; Sumpter, Bobby G [ORNL; Xiao, Kai [ORNL

    2014-01-01

    Adding a small amount of a processing additive to the casting solution of organic blends has been demonstrated to be an effective method for achieving improved power conversion efficiency (PCE) in organic photovoltaics (OPVs). However, an understanding of the nano-structural evolution occurring in the transformation from casting solution to thin photoactive films is still lacking. In this report, we investigate the effects of the processing additive diiodooctane (DIO) on the morphology of OPV blend of PBDTTT-C-T and fullerene derivative, PC71BM in a casting solution and in spun-cast thin films by using neutron/x-ray scattering, neutron reflectometry and other characterization techniques. The results reveal that DIO has no effect on the solution structures of PBDTTT-C-T and PC71BM. In the spun-cast films, however, DIO is found to promote significantly the molecular ordering of PBDTTT-C-T and PC71BM, and phase segregation, resulting in the improved PCE. Thermodynamic analysis based on Flory-Huggins theory provides a rationale for the effects of DIO on different characteristics of phase segregation as a solvent and due to evaporationg during the film formation. Such information may enable improved rational design of ternary blends to more consistently achieve improved PCE for OPVs.

  10. CAST

    NSDL National Science Digital Library

    The Council for Agricultural Science and Technology (CAST) was formed in 1972 as a result of a meeting sponsored by the National Academy of Sciences' National Research Council. CAST's mission is to "assemble, interpret, and communicate credible science-based information regionally, nationally, and internationally to legislators, regulators, policymakers, the media, the private sector and the public." Visitors will find the Education tab near the top of the page to be particularly helpful for those who want to pursue agricultural careers or learn about agricultural education, such as 4-H or Future Farmers of America. The CAST Videos section has a number of PowerPoint presentations on current topics of importance in agriculture, such as "The Science and Regulation of Food from Genetically Engineered Animals," "Food Safety and Fresh Produce," and "Probiotics in Human Health." A number of the papers that accompany the PowerPoint presentations are available for free.

  11. Land-based turbine casting initiative

    SciTech Connect

    Mueller, B.A.; Spicer, R.A. [Howmet Corp., Whitehall, MI (United States)

    1995-10-01

    The Advanced Turbine Systems (ATS) program has set goals which include a large-scale utility turbine efficiency that exceeds 60 percent (LHV) on natural gas and an industrial turbine system heat rate improvement of 15 percent. To meet these goals, technological advances developed for aircraft gas turbine engines need to be applied to land based gas turbines. These technological advances include: directionally solidified and single crystal castings, alloys tailored to exploit these microstructures, complex internal cooling schemes, and coatings. Equiaxed and directionally solidified castings are employed in current land based power generation equipment. These castings do not possess the ability to meet the efficiency targets as outlined above. The production use of premium single crystal components with complex internal cooling schemes in the latest generation of alloys is necessary to meet the ATS goals. However, at present, the use of single crystal components with complex internal cooling schemes is restricted to industrial sized or aeroderivative engines, and prototype utility sized components.

  12. Characterization of an antioxidant polylactic acid (PLA) film prepared with ?-tocopherol, BHT and polyethylene glycol using film cast extruder

    Microsoft Academic Search

    Youngjae Byun; Young Teck Kim; Scott Whiteside

    2010-01-01

    Polylactic acid (PLA) films were prepared with ?-tocopherol, buthylated hydroxytoluene (BHT), and polyethylene glycol 400 (PEG 400) using a cast film extruder in an effort to create an antioxidant film. Film properties were characterized by radical scavenging activity and thermal, physical, and gas barrier properties. Final resin compounding and pelletization was achieved by a twin screw extruder and a pelletizator

  13. Alumina casting based on gelation of gelatine

    Microsoft Academic Search

    Yali Chen; Zhipeng Xie; Jinlong Yang; Yong Huang

    1999-01-01

    A new colloidal in-situ forming technique based on the gelling property of gelatine is discussed in this paper. A warm slurry containing more than 50vol% alumina powder and a small amount of gelatine (?1wt% of powder weight) is cast into a nonporous mould, and a rigid green body can be produced upon cooling below the so-called gel point of gelatine

  14. Film Boiling and Water Film Ejection in the Secondary Cooling Zone of the Direct-Chill Casting Process

    NASA Astrophysics Data System (ADS)

    Caron, Etienne; Wells, Mary A.

    2012-02-01

    Accurate thermal modeling of the direct-chill casting process relies nowadays on increasingly complex boundary conditions for the secondary cooling zone. A two-dimensional axisymmetric finite-element model of the direct-chill casting process was developed to quantify the importance of secondary cooling at the surface compared with internal heat conduction within the billet. Boiling water heat transfer at the surface was found to dominate and be the governing factor only when stable film boiling or water film ejection take place; all other cases were dominated by internal heat conduction. The influence of various parameters (casting speed, cooling water flow rate, and thermophysical properties of the cast material) on the occurrence of water film ejection was analyzed. An exponential relationship was found between the cooling water flow rate and the minimum casting speed at which water film ejection takes place.

  15. Adaptive GPU Ray Casting Based on Spectral Stefan Suwelack1

    E-print Network

    Paris-Sud XI, Université de

    Adaptive GPU Ray Casting Based on Spectral Analysis Stefan Suwelack1 , Eric Heitz1 Roland casting has become a valuable tool for the visualization of medical image data. While the method produces this criterion can be efficiently incorporated into an adaptive ray casting algorithm. Two medical datasets

  16. Stability of cast-film extrusion of various metallocene polyethylenes R. Bouamra, J.F. Agassant, C. Peiti and J.M. Haudin

    E-print Network

    Paris-Sud XI, Université de

    Stability of cast-film extrusion of various metallocene polyethylenes R. Bouamra, J.F. Agassant, C, France 1- Introduction The Cast Film process is one of the most widely used polymer processing technology: General view of (a) the Cast Film process, (b) the Cemef experimental device The cast film process may

  17. Electroconductive PET/SWNT Films by Solution Casting

    NASA Technical Reports Server (NTRS)

    Steinert, Brian W.; Dean, Derrick R.

    2008-01-01

    The market for electrically conductive polymers is rapidly growing, and an emerging pathway for attaining these materials is via polymer-carbon nanotube (CNT) nanocomposites, because of the superior properties of CNTs. Due to their excellent electrical properties and anisotropic magnetic susceptibility, we expect CNTs could be easily aligned to maximize their effectiveness in imparting electrical conductivity to the polymer matrix. Single-walled carbon nanotubes (SWNT) were dispersed in a polyethylene terephthalate (PET) matrix by solution blending then cast onto a glass substrate to create thin, flexible films. Various SWNT loading concentrations were implemented (0.5, 1.0, and 3.0 wt.%) to study the effect of additive density. The processing method was repeated to produce films in the presence of magnetic fields (3 and 9.4 Tesla). The SWNTs showed a high susceptibility to the magnetic field and were effectively aligned in the PET matrix. The alignment was characterized with Raman spectroscopy. Impedance spectroscopy was utilized to study the electrical behavior of the films. Concentration and dispersion seemed to play very important roles in improving electrical conductivity, while alignment played a secondary and less significant role. The most interesting result proved to be the effect of a magnetic field during processing. It appears that a magnetic field may improve dispersion of unmodified SWNTs, which seems to be more important than alignment. It was concluded that SWNTs offer a good option as conductive, nucleating filler for electroconductive polymer applications, and the utilization of a magnetic field may prove to be a novel method for CNT dispersion that could lead to improved nanocomposite materials.

  18. Drop-casted polyaniline thin films on flexible substrates for supercapacitor applications

    NASA Astrophysics Data System (ADS)

    Kim, Jongmin; Sohn, J.; Jo, Yongcheol; Woo, Hyeonseok; Han, Jaeseok; Cho, Sangeun; Inamdar, A. I.; Kim, Hyungsang; Im, Hyunsik

    2014-11-01

    The PANI (polyaniline) thin films are synthesized on flexible ITO/PET (indium tin oxide/polyethylene terephthalate) substrates by using the drop-casting method. The amount of the PANI for the drop casting varies from 0.04 to 0.16 g. The morphology of the drop-casted PANI films shows a porous vermicular shape. The electrochemical supercapacitor properties of the PANI films are examined in a 0.5-M LiClO4 + PC electrolyte. The PANI films with 0.08 g of PANI show higher current density and considerably higher specific capacitance and capacity retention, compared with other PANI films. The highest specific capacitance of the films with 0.08 g of PANI is found to be ˜120 F/g, and the capacity retention is found to be as high as 70.51% after 100 charge-discharge cycles.

  19. Morphological characterization of ? phase in poly-(vinylidenefluoride) film prepared by spin cast method

    SciTech Connect

    Mehtani, Hitesh Kumar, E-mail: kkraina@gmail.com; Kumar, Rishi, E-mail: kkraina@gmail.com; Raina, K. K., E-mail: kkraina@gmail.com [School of Physics and Materials Science, Thapar University, Patiala-147004 (India)

    2014-04-24

    Poly-(Vinylidene fluoride) PVDF film was prepared by spin casting method to control the pore size of the matrix. The morphological spherulitic structure was confirmed Scanning Electron Microscopy (SEM) after gold sputtering and the presence of ? phase was ensured in spin cast PVDF film by the FTIR spectroscopy. The ? phase is very important in the application because it improve the properties like piezoelectricity by modifying PVDF crystallinity.

  20. An heuristic based practical tool for casting process design

    SciTech Connect

    Nanda, N.K.; Smith, K.A.; Voller, V.R.; Haberle, K.F. [Univ. of Minnesota, Minneapolis, MN (United States). Dept. of Civil Engineering

    1995-12-31

    The work in this paper reports on an heuristic based computer tool directed at casting process design; in particular key design parameters, such as part orientation, location of sprues, feeding rates, etc. The underlying principal used is that a given casting can be represented on identifying and classifying its critical features. The input to the system consists of the attributes of the features and the graphical output provides semi-quantitative information on key design parameters. Results on real castings match those of the expert casting designers and in some cases potential design improvements have been suggested by the system.

  1. Thickness dependence of structural relaxation in spin-cast, glassy polymer thin films

    NASA Astrophysics Data System (ADS)

    Richardson, H.; López-García, Í.; Sferrazza, M.; Keddie, J. L.

    2004-11-01

    The isothermal structural relaxation of glassy, spin-cast polymer thin films has been investigated. Specifically, the thickness h of freshly cast poly(methyl methacrylate) thin films was measured over time using spectroscopic ellipsometry. The spin-cast films exhibit a gradual decrease in thickness, which is attributed to structural relaxation of the glass combined with simultaneous solvent loss. In all cases, h was found to be greater than the equilibrium thickness h? , which is obtained by cooling slowly from the melt. It is observed that both the rate of the volume relaxation and the fractional departure from h? (referred to as ?0 ) increase with increasing film thickness. In the limit of very thin films, the initial h is close to h? , and ?0 is small, whereas in thick films (>500nm) , a plateau value of ?0 of 0.16 is observed, which is close to the volume fraction of the solvent at the vitrification point. This dependence of ?0 on thickness is observed regardless of the substrate, polymer molecular weight, or angular velocity during spin casting. Enhanced mobility near film surfaces could be leading to greater relaxation in thinner films prior to, and immediately after, the vitrification of the polymer during the deposition process.

  2. Interfacial glass transition profiles in ultrathin, spin cast polymer films Scott Sills and Rene M. Overneya)

    E-print Network

    Interfacial glass transition profiles in ultrathin, spin cast polymer films Scott Sills and Rene´ M of polymers is the glass tran- sition temperature, Tg . For thin homopolymer films, it has been recognized, California 95120 Received 13 October 2003; accepted 16 December 2003 Interfacial glass transition temperature

  3. Properties of cast films made of chayote (Sechium edule Sw.) tuber starch reinforced with cellulose nanocrystals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In this study, cellulose (C) and cellulose nanocrystals (CN) were blended with chayote tuber (Sechium edule Sw.) starch (CS) in formulations cast into films. The films were conditioned at different storage temperatures and relative humidity (RH), and analyzed by mechanical tests, X-ray diffraction, ...

  4. Grain Refinement of Permanent Mold Cast Copper Base Alloys

    SciTech Connect

    M.Sadayappan; J.P.Thomson; M.Elboujdaini; G.Ping Gu; M. Sahoo

    2005-04-01

    Grain refinement is a well established process for many cast and wrought alloys. The mechanical properties of various alloys could be enhanced by reducing the grain size. Refinement is also known to improve casting characteristics such as fluidity and hot tearing. Grain refinement of copper-base alloys is not widely used, especially in sand casting process. However, in permanent mold casting of copper alloys it is now common to use grain refinement to counteract the problem of severe hot tearing which also improves the pressure tightness of plumbing components. The mechanism of grain refinement in copper-base alloys is not well understood. The issues to be studied include the effect of minor alloy additions on the microstructure, their interaction with the grain refiner, effect of cooling rate, and loss of grain refinement (fading). In this investigation, efforts were made to explore and understand grain refinement of copper alloys, especially in permanent mold casting conditions.

  5. Single-step fabrication of quantum funnels via centrifugal colloidal casting of nanoparticle films.

    PubMed

    Kim, Jin Young; Adinolfi, Valerio; Sutherland, Brandon R; Voznyy, Oleksandr; Kwon, S Joon; Kim, Tae Wu; Kim, Jeongho; Ihee, Hyotcherl; Kemp, Kyle; Adachi, Michael; Yuan, Mingjian; Kramer, Illan; Zhitomirsky, David; Hoogland, Sjoerd; Sargent, Edward H

    2015-01-01

    Centrifugal casting of composites and ceramics has been widely employed to improve the mechanical and thermal properties of functional materials. This powerful method has yet to be deployed in the context of nanoparticles-yet size-effect tuning of quantum dots is among their most distinctive and application-relevant features. Here we report the first gradient nanoparticle films to be constructed in a single step. By creating a stable colloid of nanoparticles that are capped with electronic-conduction-compatible ligands we were able to leverage centrifugal casting for thin-films devices. This new method, termed centrifugal colloidal casting, is demonstrated to form films in a bandgap-ordered manner with efficient carrier funnelling towards the lowest energy layer. We constructed the first quantum-gradient photodiode to be formed in a single deposition step and, as a result of the gradient-enhanced electric field, experimentally measured the highest normalized detectivity of any colloidal quantum dot photodetector. PMID:26165185

  6. 10. DETAIL OF CAST IRON COLUMN BASE ON FIRST FLOOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    10. DETAIL OF CAST IRON COLUMN BASE ON FIRST FLOOR STOREFRONT, SHOWING MANUFACTURER'S STAMP: IOWA IRON WOKS CO. DUBUQUE. VIEW TO SOUTHWEST. - Commercial & Industrial Buildings, Dubuque Seed Company Warehouse, 169-171 Iowa Street, Dubuque, Dubuque County, IA

  7. Effect of viscoelastic stress state at die exit on extrusion film casting process: Theoretical study

    NASA Astrophysics Data System (ADS)

    Barborik, Tomas; Zatloukal, Martin

    2015-04-01

    In this work, viscoelastic, isothermal extrusion film casting modeling utilizing 1D membrane model and modified Leonov model was performed in order to understand the role of viscoelastic stress state at the die exit on the polymer melt film stretching in the post die area. Experimental data for LDPE and theoretical predictions based on the eXtended Pom-Pom (XPP) model taken from the open literature were used for the validation purposes. It was found that predicting capabilities of 1D membrane model utilizing XPP and modified Leonov model are comparable for the given processing conditions and material. Consequent theoretical parametric study revealed that increase in the viscoelastic stress state at the die exit, characterized as the ratio of second and first normal stress differences, -N2/N1, leads to increase in neck-in phenomenon. This suggests that specific attention should be paid to optimization of the extrusion die design in order to stabilize polymer melt film stretching in the post die area.

  8. Effect of carboxymethyl cellulose concentration on physical properties of biodegradable cassava starch-based films

    Microsoft Academic Search

    Wirongrong Tongdeesoontorn; Lisa J Mauer; Sasitorn Wongruong; Pensiri Sriburi; Pornchai Rachtanapun

    2011-01-01

    BACKGROUND: Cassava starch, the economically important agricultural commodity in Thailand, can readily be cast into films. However, the cassava starch film is brittle and weak, leading to inadequate mechanical properties. The properties of starch film can be improved by adding plasticizers and blending with the other biopolymers. RESULTS: Cassava starch (5%w\\/v) based films plasticized with glycerol (30 g\\/100 g starch)

  9. Effect of transglutaminase treatment on the properties of cast films of soy protein isolates.

    PubMed

    Tang, Chuan-He; Jiang, Yan; Wen, Qi-Biao; Yang, Xiao-Quan

    2005-11-21

    The objective of this work was to investigate the effect of microbial transglutaminase (MTGase) treatment on the properties and microstructures of soy protein isolate (SPI) films cast with 0.6 plasticizer per SPI (gg(-1)) of glycerol, sorbitol and 1:1 mixture of glycerol and sorbitol, respectively. Tensile strength (TS), elongation at break (EB), water vapor transmission rate (WVTR) or water vapor permeability (WVP), moisture content (MC), total soluble matter (TSM), lipid barrier property and surface hydrophobicity of control and MTGase-treated films were evaluated after conditioning film specimens at 25 degrees C and 50% relative humidity (RH) for 48 h. The treatment by 4 units per SPI (Ug(-1)) of MTGase increased the TS and surface hydrophobicity by 10-20% and 17-56%, respectively, and simultaneously significantly (P< or =0.05) decreased the E, MC and transparency. The WVTR or TSM of SPI films seemed to be not significantly affected by enzymatic treatment (P>0.05). The MTGase treatment also slowed down the moisture loss rate of film-forming solutions with various plasticizers during the drying process, which was consistent with the increase of surface hydrophobicity of SPI films. Microstructural analyses indicated that the MTGase-treated films of SPI had a rougher surface and more homogeneous or compact cross-section compared to the controls. These results suggested that the MTGase treatment of film-forming solutions of SPI prior to casting could greatly modify the properties and microstructures of SPI films. PMID:16084619

  10. Influence of macromolecular architecture on necking in polymer extrusion film casting process

    NASA Astrophysics Data System (ADS)

    Pol, Harshawardhan; Banik, Sourya; Azad, Lal Busher; Thete, Sumeet; Doshi, Pankaj; Lele, Ashish

    2015-05-01

    Extrusion film casting (EFC) is an important polymer processing technique that is used to produce several thousand tons of polymer films/coatings on an industrial scale. In this research, we are interested in understanding quantitatively how macromolecular chain architecture (for example long chain branching (LCB) or molecular weight distribution (MWD or PDI)) influences the necking and thickness distribution of extrusion cast films. We have used different polymer resins of linear and branched molecular architecture to produce extrusion cast films under controlled experimental conditions. The necking profiles of the films were imaged and the velocity profiles during EFC were monitored using particle tracking velocimetry (PTV) technique. Additionally, the temperature profiles were captured using an IR thermography and thickness profiles were calculated. The experimental results are compared with predictions of one-dimensional flow model of Silagy et al1 wherein the polymer resin rheology is modeled using molecular constitutive equations such as the Rolie-Poly (RP) and extended Pom Pom (XPP). We demonstrate that the 1-D flow model containing the molecular constitutive equations provides new insights into the role of macromolecular chain architecture on film necking.1D. Silagy, Y. Demay, and J-F. Agassant, Polym. Eng. Sci., 36, 2614 (1996).

  11. Reversible tuning of chemical structure of Nafion cast film by heat and acid treatment.

    PubMed

    Singhal, Nancy; Datta, Anindya

    2015-02-12

    Effects of annealing have been studied on the chemical structure, water uptake, and acidity of the cast Nafion thin film of thickness ? 6 ?m using a fluorescent probe, 2-(3'-pyridyl)benzimidazole (3PBI), and attenuated total reflactance infrared (ATR-IR) spectroscopy. Nonannealed films and thick Nafion 117 membrane have been used as reference materials, in order to develop a complete understanding of the effect. Annealing has been found to cause a decrease in acidity of otherwise highly acidic ionomer, as sensed by the fluorescent probe and loss of water, as reflected in the ATR-IR spectrum. This observation is surprising and cannot be explained in the light of previous reports of physical changes. Our ATR-IR study has revealed changes in the chemical structure of the hydrophilic part of the ionomer, leading to the formation of sulfonic acid anhydrides. This phenomenon can rationalize the decreased acidity reported in our fluorescence study. Interestingly, acid treatment of the annealed film restores the acidity of the unannealed films. This cannot be rationalized simply by a greater proton uptake from the solution, as the film has to be electroneutral. It appears that the anhydrides formed during the annealing process undergo acid hydrolysis, leading to an increase in the number of SO3(-) groups and, consequently, an increase in the number of H3O(+) ions in the water channels. Besides, the films can be hydrated to an extent that is much greater than Nafion membranes, but the water uptake of acid treated annealed film is slightly less than that of nonannealed films. Hence, we conclude that, along with annealing, acid treatment, a procedure that is generally not performed on the cast films, is an important pretreatment procedure to improve the acidity and hence the transport properties of the cast film. PMID:25275923

  12. Antireflective polyimide based films

    NASA Astrophysics Data System (ADS)

    Cao, Yuanmei

    The goal of this work was to prepare antireflective and anti-abrasion films using polyimide and organically modified silica nanoparticle thin films. A series of thin film were prepared from colorless and soluble polyimide with organically modified silica colloids via a solution casting method. The polyimide was selected for its optical properties. Three type of organically modified silica nanoparticles were prepared by grafting polysiloxane, polyfluoroester and fluoroalkyl groups onto silica nanoparticles. The molecular weight of the polysiloxane, polyfluoroester and the amount of fluorinated alkyl groups were varied. The organically modified silica colloids were characterized by TEM, DLS, FTIR, 1H NMR, solid state 13C NMR and solid state 29Si NMR. The coatings were characterized by UV-Vis transmittance spectra and SEM. The effect of modified silica loading, the molecular weight of polymer and type of solvent on AR properties were studied. An enhancement in antireflective activity was observed for 1 wt% LPDMS modified (low molecular weight) silica coatings, 3 wt% fluorosilica-10 and 3% L-MPS-PF-SILICA nanoparticles (low molecular weight polyfluoroester modified silica) in dimethylacetamide (DMAc). In comparison with cyclopentanone (CPT), DMAc favors migration of silica particles towards coating-air interface giving higher transmittance. The migration of particles to the surface and consequent increased surface roughness were observed by SEM. The present study suggested a roll to roll solution casting method to create antireflective coatings. This approach had potential to be used for a one-step large-scale manufacturing of antireflective coating. Four acrylated bismaleimide were made via two-step process. The first step involved the solution imidization to form hydroxylated bismaleimide. In the second step, hydroxylated bismaleimide was reacted with acryloyl chloride to form acrylated bismaleimide. The acrylated bismaleimide were characterized by FTIR, 1H NMR, 13C NMR, GPC and mass spectra. The acrylated bismaleimide was formulated with acryloyl morpholine and photoinitiator with or without addition of PDMS-silica nanoparticles to achieve UV-curable thin films. The photo-cure kinetics of four neat acrylated bismaleimide and the formulation were investigated by real-time FTIR, photo-DSC and rheometer. The kinetic analysis revealed that PDMS-silica accelerated the photocure rate and increased the conversion of both acrylate double bond and maleimide double bond. The dispersion of PDMS-silica nanoparticles affected the abrasion resistance. The optimal abrasion resistance was achieved with 3.0% wt PDMS modified silica nanoparticle loading.

  13. Characterization of thin film properties of melamine based dendrimer nanoparticles 

    E-print Network

    Boo, Woong Jae

    2005-02-17

    concentrations, casting temperatures, and substrates. As a result of these experiments, unique phenomena of highly ordered uniform 2-D contraction separations were observed during the solvent evaporation from the dendrimer films. The cast films from...

  14. Mercuric iodide composite films using polyamide, polycarbonate and polystyrene fabricated by casting

    NASA Astrophysics Data System (ADS)

    Ugucioni, J. C.; Ghilardi Netto, T.; Mulato, M.

    2010-10-01

    Mercuric iodide (HgI2) composite films were obtained by using the casting technique. Insulator polymers such as polyamide, polycarbonate and polystyrene were mixed to HgI2 crystallites forming a final sub-millimeter thick self-standing film. Fabrication temperature varied from 10 to 100 °C, and total fabrication time reached at most 5 min. The larger the fabrication temperature, the thinner the film and the smaller its electrical resistivity. Electrical characterization was performed in the dark, under UV illumination and under mammographic X-ray exposure. The final properties of the films are discussed and related to fabrication conditions. The optimized composite film might be a better candidate for use as X-ray detector for medical imaging, in place of the single HgI2 crystalline device.

  15. Strong composite films with layered structures prepared by casting silk fibroin-graphene oxide hydrogels

    NASA Astrophysics Data System (ADS)

    Huang, Liang; Li, Chun; Yuan, Wenjing; Shi, Gaoquan

    2013-04-01

    Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 +/- 16 MPa and a failure strain of 1.8 +/- 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 +/- 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets.Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 +/- 16 MPa and a failure strain of 1.8 +/- 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 +/- 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets. Electronic supplementary information (ESI) available: XPS spectrum of the SF-GO hybrid film, SEM images of lyophilized GO dispersion and the failure surface of GO film. See DOI: 10.1039/c3nr00196b

  16. Aluminum-Based Cast In Situ Composites: A Review

    NASA Astrophysics Data System (ADS)

    Pramod, S. L.; Bakshi, Srinivasa R.; Murty, B. S.

    2015-06-01

    In situ composites are a class of composite materials in which the reinforcement is formed within the matrix by reaction during the processing. In situ method of composite synthesis has been widely followed by researchers because of several advantages over conventional stir casting such as fine particle size, clean interface, and good wettability of the reinforcement with the matrix and homogeneous distribution of the reinforcement compared to other processes. Besides this, in situ processing of composites by casting route is also economical and amenable for large scale production as compared to other methods such as powder metallurgy and spray forming. Commonly used reinforcements for Al and its alloys which can be produced in situ are Al2O3, AlN, TiB2, TiC, ZrB2, and Mg2Si. The aim of this paper is to review the current research and development in aluminum-based in situ composites by casting route.

  17. Aluminum-Based Cast In Situ Composites: A Review

    NASA Astrophysics Data System (ADS)

    Pramod, S. L.; Bakshi, Srinivasa R.; Murty, B. S.

    2015-02-01

    In situ composites are a class of composite materials in which the reinforcement is formed within the matrix by reaction during the processing. In situ method of composite synthesis has been widely followed by researchers because of several advantages over conventional stir casting such as fine particle size, clean interface, and good wettability of the reinforcement with the matrix and homogeneous distribution of the reinforcement compared to other processes. Besides this, in situ processing of composites by casting route is also economical and amenable for large scale production as compared to other methods such as powder metallurgy and spray forming. Commonly used reinforcements for Al and its alloys which can be produced in situ are Al2O3, AlN, TiB2, TiC, ZrB2, and Mg2Si. The aim of this paper is to review the current research and development in aluminum-based in situ composites by casting route.

  18. Turbine blade casting die design method based on FBS theory

    Microsoft Academic Search

    Zhou Tong; Wang Wenhu; Wang Hong

    2010-01-01

    This paper put forward a method which is based on function-behavior-structure (FBS) according to the characters and demands of turbine blade die design. Through the analysis of the designing process of cavity, the paper researched on the mapping method of FBS which realized the automatic design of the cavity of precision casting mould on the basis of rule deduction and

  19. Properties of cast films from hemp (Cannabis sativa L.) and soy protein isolates. A comparative study.

    PubMed

    Yin, Shou-Wei; Tang, Chuan-He; Wen, Qi-Biao; Yang, Xiao-Quan

    2007-09-01

    The properties of cast films from hemp protein isolate (HPI) including moisture content (MC) and total soluble mass (TSM), tensile strength (TS) and elongation at the break (EAB), and surface hydrophobicity were investigated and compared to those from soy protein isolate (SPI). The plasticizer (glycerol) level effect on these properties and the interactive force pattern for the film network formation were also evaluated. At some specific glycerol levels, HPI films had similar MC, much less TSM and EAB, and higher TS and surface hydrophobicity (support matrix side), as compared to SPI films. The TS of HPI and SPI films as a function of plasticizer level (in the range of 0.3-0.6 g/g of protein) were well fitted with the exponential equation with coefficient factors of 0.991 and 0.969, respectively. Unexpectedly, the surface hydrophobicity of HPI films (including air and support matrix sides) increased with increasing the glycerol level (from 0.3 to 0.6 g/g of protein). The analyses of protein solubility of film in various solvents and free sulfydryl group content showed that the disulfide bonds are the prominent interactive force in the HPI film network formation, while in the SPI case, besides the disulfide bonds, hydrogen bonds and hydrophobic interactions are also to a similar extent involved. The results suggest that hemp protein isolates have good potential to be applied to prepare protein film with some superior characteristics, e.g., low solubility and high surface hydrophobicity. PMID:17696443

  20. Effect of Material Structure and Additives on the Optical Properties of PP Cast Films

    Microsoft Academic Search

    Gernot M. Wallner; Katharina Resch; Christian Teichert; Markus Gahleitner; Wolfgang Binder

    2006-01-01

    Summary.  Polypropylene homopolymer and ethylene\\/propylene-random-copolymer cast films formulated with slip, anti-blocking, and acid\\u000a scavenger aids were analyzed as to material structure and optical properties. The structural and topographical characterization\\u000a was done by atomic force microscopy and by spectroscopic methods. Optical properties were determined using a hazemeter and\\u000a an UV\\/VIS\\/NIR spectrophotometer. As to the effect of additives it was established that slip

  1. Nanometer-scale ordering in cast films of columnar metallomesogen as revealed by STM observations.

    PubMed

    Kakegawa, Norishige; Hoshino, Naomi; Matsuoka, Yuki; Wakabayashi, Noboru; Nishimura, Shin-Ichiro; Yamagishi, Akihiko

    2005-05-14

    STM observations were performed on a cast film of a columnar metallomesogen ([Cr(5C8)3]; 5C8 = 1-(3,4,5-trioctyloxyphenyl)-3-(3,4-dioctyloxyphenyl)propane-1,3-dionate anion) on a graphite surface, revealing the nanometer-scale surface ordering into an oblique lattice (a = 10.5 nm, b = 11.5 nm, alpha = 55 degrees) possibly due to the DeltaLambda-chiral interactions. PMID:15877133

  2. Strong composite films with layered structures prepared by casting silk fibroin-graphene oxide hydrogels.

    PubMed

    Huang, Liang; Li, Chun; Yuan, Wenjing; Shi, Gaoquan

    2013-05-01

    Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 ± 16 MPa and a failure strain of 1.8 ± 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 ± 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets. PMID:23538717

  3. Application of a tungsten/tungsten-carbide film to H-13 casting dies by plasma assisted deposition

    SciTech Connect

    Horswill, N.; Jetzer, W.; Fetherston, P.; Conrad, J.R. [Univ. of Wisconsin, Madison, WI (United States)

    1995-12-31

    Die casting is used extensively to produce Al, Mg and Zn alloy parts. H-13, a widely used die material, is a medium carbon steel alloy with Cr, Mo, and Si. A problem with die casting is soldering, thermal fatigue cracking, and carbon buildup which cause degradation of the casting. Application of a metallic coating to the die has been shown to increase the resistance to thermal fatigue cracking. In this study, a tungsten/tungsten carbide thin film was deposited on a casting die of H-13 die steel by a two step Plasma Source Ion Enhanced Deposition process using an argon and methane plasmas. The film was characterized using Auger Electron Spectroscopy, Scanning Electron Microscopy and Electron Dispersive Spectroscopy. The die and representative castings (from regular intervals during the lifetime of the die) were examined for evidence of soldering, thermal fatigue cracking and carbon buildup.

  4. Application in casting defect lossless examination based on surf

    NASA Astrophysics Data System (ADS)

    Fan, Youchen; Sun, Huayan; Wang, Haoxiang

    2013-08-01

    Based on the study of measures of the algorithm casting defect lossless examination and characteristics of X-ray imaging, a new automatic detection based on SURF is presented. Firstly, the algorithm detects the interested points of specifically component model in the standard image samples by SURF. Then the interested points of inspection produce are detected when the rotary worktable makes one revolution, at the same time, the interested points between model and produce are matched. The number of matched points is the basis for whether the product contains the component. Experimental results show that this method is effective in determining the component model well or not, which provides a novel method for casting defect lossless examination.

  5. A rule-based expert system approach to process selection for cast components

    Microsoft Academic Search

    Er Ahmet; R. Dias

    2000-01-01

    A knowledge-based expert system at the discretion of casting product designers can be employed as a real-time expert advisor to assist product designers to achieve the correct casting design and select the most appropriate casting process for a given component. This paper proposes a rule-based expert system approach for casting process selection, and describes an ongoing rule prototype development. The

  6. Crystallographic textures and morphologies of solution cast Ibuprofen composite films at solid surfaces.

    PubMed

    Kellner, Thomas; Ehmann, Heike M A; Schrank, Simone; Kunert, Birgit; Zimmer, Andreas; Roblegg, Eva; Werzer, Oliver

    2014-11-01

    The preparation of thin composite layers has promising advantages in a variety of applications like transdermal, buccal, or sublingual patches. Within this model study the impact of the matrix material on the film forming properties of ibuprofen-matrix composite films is investigated. As matrix materials polystyrene, methyl cellulose, or hydroxyl-ethyl cellulose were used. The film properties were either varied by the preparation route, i.e., spin coating or drop casting, or via changes in the relative ratio of the ibuprofen and the matrix material. The resulting films were investigated via X-ray diffraction and atomic force microscope experiments. The results show that preferred (100) textures can be induced via spin coating with respect to the glass surface, while the drop casting results in a powder-like behavior. The morphologies of the films are strongly impacted by the ibuprofen amount rather than the preparation method. A comparison of the various matrix materials in terms of their impact on the dissolution properties show a two times faster zero order release from methyl cellulose matrix compared to a polystyrene matrix. The slowest rate was observed within the hydroxyl ethyl cellulose as the active pharmaceutical ingredients (APIs) release is limited by diffusion through a swollen matrix. The investigation reveals that the ibuprofen crystallization and film formation is only little effected by the selected matrix material than that compared to the dissolution. A similar experimental approach using other matrix materials may therefore allow to find an optimized composite layer useful for a defined application. PMID:25275801

  7. Beryllium localization in base metal dental casting alloys.

    PubMed

    Covington, J S; McBride, M A; Slagle, W F; Disney, A L

    1985-09-01

    Investigation of dissolution of base metal dental casting alloy constituents in aqueous solutions revealed an unexpectedly high level of beryllium as compared with the other constituents. Analysis of atomic emission spectroscopy is presented here showing the outer surface (0-100 A) is decidedly enriched in beryllium as compared with the bulk composition of the alloy. This localization is consistent in all samples and forms of the alloy tested. PMID:4077894

  8. Changes in the composition of a nickel-base partial denture casting alloy upon fusion and casting.

    PubMed

    Lewis, A J

    1975-02-01

    Three series of tensile test pieces were produced using a nickel-base partial denture casting alloy. For the first series induction heating was employed for melting the alloy, for the second a resistance crucible, and for the third an oxy-acetylene torch. In each series the same metal was cast sequentially five times, following which samples of the alloy were subjected to a ten element quantitative analysis to ascertain compositional changes associated with the three methods of fusion. PMID:1100022

  9. Method of casting pitch based foam

    DOEpatents

    Klett, James W. (Knoxville, TN)

    2002-01-01

    A process for producing molded pitch based foam is disclosed which minimizes cracking. The process includes forming a viscous pitch foam in a container, and then transferring the viscous pitch foam from the container into a mold. The viscous pitch foam in the mold is hardened to provide a carbon foam having a relatively uniform distribution of pore sizes and a highly aligned graphic structure in the struts.

  10. Fluid casting of particle-based articles

    DOEpatents

    Menchhofer, Paul (Oak Ridge, TN)

    1995-01-01

    A method for the production of articles made of a particle-based material; e.g., ceramics and sintered metals. In accordance with one aspect of the invention, a thermally settable slurry containing a relatively high concentration of the particles is introduced into an immiscible, heated fluid. The slurry sets or hardens into a shape determined by the physical characteristics of the fluid and the manner of introduction of the slurry into the fluid. For example, the slurry is pulse injected into the fluid to provide spherical articles. The hardened spheres may then be sintered to consolidate the particles and provide a high density product.

  11. Evaporation-induced ordering in solution-cast block copolymer thin films

    NASA Astrophysics Data System (ADS)

    Paradiso, Sean; Delaney, Kris; Ceniceros, Hector; Garcia-Cervera, Carlos; Fredrickson, Glenn

    2013-03-01

    Block copolymer thin films are currently being investigated for a wide variety of applications, ranging from separation membranes to organic photovoltaics and lithographic masks. Over the last decade or so, there has been mounting interest in using solvent casting techniques to control morphology selection in thin films either through spin coating, drop casting, or simple annealing under a mixture of solvent vapors. While these added degrees of freedom and process variables offer the promise of enhanced morphology control, they necessarily add extra dimensions and inter-dependencies between parameters that must be sorted out before this control can be effectively exercised. To this end, we have adapted a dynamical extension of Self-Consistent Field Theory to study the dynamics of ordering from a dilute copolymer solution to a dry, ordered thin film. This talk will offer a visual summary of the range in behavior available to a single copolymer + neutral solvent system in both 2D (lamella-forming) and 3D (cylinder-forming) environments. In addition, a brief analysis will be presented on the competing time scales, equilibrium, and non-equilibrium effects that appear to govern the initiation event and propagation of evaporation-induced ordering fronts.

  12. The recovery of latent fingermarks and DNA using a silicone-based casting material

    Microsoft Academic Search

    Rita Shalhoub; Ignacio Quinones; Carole Ames; Bryan Multaney; Stuart Curtis; Haj Seeboruth; Stephen Moore; Barbara Daniel

    2008-01-01

    There are many techniques available for the recovery of fingermarks at scenes of crime including the possibility of taking casts of the marks. Casts can be advantageous in cases where other destructive recovery techniques might not be suitable, such as when recovering finger marks deposited on valued or immobile items.In this research, Isomark™ (a silicone-based casting material) was used to

  13. A Role Casting Method Based on Emotions in a Story Generation System

    E-print Network

    Thawonmas, Ruck

    A Role Casting Method Based on Emotions in a Story Generation System Ruck Thawonmas1 , Masanao point out a problem in the role casting method of a story generation system called OPIATE and then propose a solution to this problem. The existing casting method does not take into account the emotions

  14. Streaming Model Based Volume Ray Casting Implementation for Cell Broadband Engine

    E-print Network

    JaJa, Joseph F.

    Streaming Model Based Volume Ray Casting Implementation for Cell Broadband Engine Jusub Kim grows. While a number of volumetric rendering techniques have been widely used, ray casting has been, the use of ray casting has been limited to datasets that are very small because of its high demands

  15. Solvent-cast PCL films support the regeneration of NG108-15 nerve cells

    NASA Astrophysics Data System (ADS)

    Sun, Mingzhu; Downes, Sandra

    2007-07-01

    The reconstruction of peripheral nerve defects over a short distance (10-20mm) could benefit from the development of novel biomaterials. Bio-degradable and bio-compatible materials are being pursued to replace the currently used nerve autografts. We hypothesize that physical properties, particularly surface texture, could have substantial effects on the hydrophilicity of some synthetic polymers and subsequently the compatibility of them with cells. In this study, poly (?-caprolactone) (PCL) films have been cast using four solvents from different chemical families and evaluated for their suitability and potential use as a nerve conduit substratum. The following solvents: dichloromethane (DCM, Halocarbon), methyl acetate (MA, Ester), tetrahydrofuran (THF, Ether) and acetic acid (AA, organic acid) were used to produce PCL films. The physical properties of these PCL films, average surface roughness (Ra) and wettability were measured. Atomic Force Microscopy (AFM) and Scanning Electron Microscopy (SEM) techniques were applied to obtain information on the surface texture. Motor neuron-like NG108-15 cells were used as a model to evaluate the biocompatibility of the films. It was found that same polymer when processed using different solvents could produce materials with markedly different physical and biochemical properties. Importantly, all PCL films were supportive for the growth and differentiation of NG108-15 cells.

  16. Cast Fe-base cylinder/regenerator housing alloy

    NASA Technical Reports Server (NTRS)

    Larson, F.; Kindlimann, L.

    1980-01-01

    The development of an iron-base alloy that can meet the requirements of automotive Stirling engine cylinders and regenerator housings is described. Alloy requirements are as follows: a cast alloy, stress for 5000-hr rupture life of 200 MPa (29 ksi) at 775 C (1427 F), oxidation/corrosion resistance comparable to that of N-155, compatibility with hydrogen, and an alloy cost less than or equal to that of 19-9DL. The preliminary screening and evaluation of ten alloys are described.

  17. Natural antimicrobial ingredients incorporated in biodegradable films based on cassava starch

    Microsoft Academic Search

    Viviane Kechichian; Cynthia Ditchfield; Pricila Veiga-Santos; Carmen C. Tadini

    2010-01-01

    Biodegradable films based on cassava starch and with addition of natural antimicrobial ingredients were prepared using the casting technique. The tensile properties tensile strength (TS) [MPa] and percent elongation (E) at break [%] and the water vapor transmission (WVT) of the biodegradable films were evaluated and compared with the control (without antimicrobial ingredients). The evaluation of the Colony Forming Units

  18. Coccidioidomycosis among cast and crew members at an outdoor television filming event--California, 2012.

    PubMed

    Wilken, Jason A; Marquez, Patricia; Terashita, Dawn; McNary, Jennifer; Windham, Gayle; Materna, Barbara

    2014-04-18

    In March 2013, the California Department of Public Health (CDPH) identified two Doctor's First Reports of Occupational Injury or Illness (DFRs) regarding Los Angeles County residents who had worked at the same jobsite in January 2012 and had been evaluated for possible work-associated coccidioidomycosis (valley fever). Occupational exposure to Coccidioides, the causative fungi, typically is associated with soil-disrupting activities. The physicians noted that both workers were cast or crew members filming a television series episode, and the site of possible exposure was an outdoor set in Ventura County, California. On the basis of their job titles, neither would have been expected to have been engaged in soil-disrupting activities. Los Angeles County Department of Public Health (LACDPH) conducted an outbreak investigation by using CDPH-provided occupational surveillance records, traditional infectious disease surveillance, and social media searches. This report describes the results of that investigation, which identified a total of five laboratory-confirmed and five probable cases linked to this filming event. The employer and site manager were interviewed. The site manager stated that they would no longer allow soil-disruptive work at the site and would incorporate information about the potential risk for Coccidioides exposure onsite into work contracts. Public health professionals, clinicians, and the television and film industry should be aware that employees working outdoors in areas where Coccidioides is endemic (e.g., central and southern California), even those not engaged in soil-disruptive work, might be at risk for coccidioidomycosis. PMID:24739339

  19. Improved mechanical properties of solution-cast silicone film reinforced with electrospun polyurethane nanofiber containing carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Tijing, Leonard D.; Park, Chan-Hee; Kang, Seung-Ji; Amarjargal, Altangerel; Kim, Tae-Hyung; Pant, Hem Raj; Kim, Han Joo; Lee, Dong Hwan; Kim, Cheol Sang

    2013-01-01

    In this study, we describe the enhancing ability of electrospun polyurethane (PU) nanofibers containing carbon nanotubes (CNTs) as nanofillers for silicone film in improving the physico-mechanical properties of the composite material. We prepared the samples combining two simple techniques: solution casting and electrospinning. Neat PU nanofibers alone are good reinforcing materials but the presence of CNTs inside the PU nanofibers has drastically improved the mechanical properties of the silicone composite film. The silicone film increased its tensile strength by 226% and its tensile modulus by more than 14-fold when CNT/PU nanofibers were incorporated.

  20. Microstructure of aluminum twin-roll casting based on Cellular Automation

    Microsoft Academic Search

    Xiao-bo LIU; Qing-yan XU; Tao JING; Bai-cheng LIU

    2008-01-01

    Nucleation and growth model based on Cellular Automation(CA) incorporated with macro heat transfer calculation was presented to simulate the microstructure of aluminum twin-roll casting. The dynamics model of dendrite tip (KGT model) was amended in view of characteristics of aluminum twin-roll casting. Through the numerical simulation on solidification structure under different casting speeds, it can be seen that when the

  1. Suitability of emeraldine base polyaniline-PVA composite film for carbon dioxide sensing

    Microsoft Academic Search

    Mihai Irimia-Vladu; Jeffrey W. Fergus

    2006-01-01

    A CO2 sensor based on a composite thin film of emeraldine base polyaniline and poly (vinyl alcohol) cast from N-methyl pyrrolidone on an interdigitated electrode was characterized using impedance spectroscopy. The response of the sensor was slow and smaller in magnitude as compared to reports in the literature for similar sensors. Materials characterization indicated that the desired emeraldine base phase

  2. The recovery of latent fingermarks and DNA using a silicone-based casting material.

    PubMed

    Shalhoub, Rita; Quinones, Ignacio; Ames, Carole; Multaney, Bryan; Curtis, Stuart; Seeboruth, Haj; Moore, Stephen; Daniel, Barbara

    2008-07-01

    There are many techniques available for the recovery of fingermarks at scenes of crime including the possibility of taking casts of the marks. Casts can be advantageous in cases where other destructive recovery techniques might not be suitable, such as when recovering finger marks deposited on valued or immobile items. In this research, Isomark (a silicone-based casting material) was used to recover casts of finger marks placed on a variety of substrates. Casts were enhanced using cyanoacrylate fuming. Good quality marks were successfully recovered from a range of smooth, non-porous surfaces. Recovery from semi-porous surfaces was shown to be inefficient. DNA was subsequently extracted from the casts using QIAamp Mini extraction kits, amplified and profiled. Full DNA profiles were obtained 34% of samples extracted. PMID:18502070

  3. Determination of the Lifetime of a Double-Oxide Film in Al Castings

    NASA Astrophysics Data System (ADS)

    El-Sayed, Mahmoud Ahmed; Salem, Hanadi A. G.; Kandeil, Abdelrazek Youssef; Griffiths, W. D.

    2014-08-01

    One of the most important casting defects in Al alloys is thought to be the double-oxide film defect (bifilm) which has been reported to have a deleterious effect on the reproducibility of the mechanical properties of Al castings. Previous research has suggested that the atmosphere inside such bifilms could be consumed by reaction with the surrounding melt, which might decrease the size of the defects and reduce their harmful effect on mechanical properties. In order to follow the change in the composition of the interior atmosphere of a bifilm, analog air bubbles were held inside Al alloy melts, for varying lengths of time, and subjected to stirring, followed by solidification. The bubble contents were then analyzed using a mass spectrometer to determine the changes in their compositions with time. The results suggested that initially oxygen and then nitrogen inside the bubble were consumed, and hydrogen dissolved in the melt diffused into the bubble. The consumption rates of O and N as well as the rate of H diffusion were dependent upon the type of oxide, which was dependent on the alloy composition. The reaction rates were the fastest with MgO (in an Al-5Mg alloy), slower with alumina (in commercial-purity Al alloy), and the slowest with MgAl2O4 spinel (in an Al-7Si-0.3Mg alloy). It was estimated that the times required for typical bifilm defects in the different alloys to lose their entire oxygen and nitrogen contents were about 345 seconds (~6 minutes), in the case of Al-5Mg; 538 seconds (~9 minutes), in the case of a commercial purity alloy; and 1509 seconds (~25 minutes), in the case of the Al-7Si-0.3Mg alloy (2L99) due to the different oxides that the different alloys would be expected to form.

  4. Application of Film-Casting Technique to Investigate Drug-Polymer Miscibility in Solid Dispersion and Hot-Melt Extrudate.

    PubMed

    Parikh, Tapan; Gupta, Simerdeep Singh; Meena, Anuprabha K; Vitez, Imre; Mahajan, Nidhi; Serajuddin, Abu T M

    2015-07-01

    Determination of drug-polymer miscibility is critical for successful development of solid dispersions. This report details a practical method to predict miscibility and physical stability of drug with various polymers in solid dispersion and, especially, in melt extrudates by applying a film-casting technique. Mixtures of itraconazole (ITZ) with hydroxypropylmethylcellulose phthalate (HPMCP), Kollidon(®) VA 64, Eudragit(®) E PO, and Soluplus(®) were film-casted, exposed to 40°C/75% RH for 1 month and then analyzed using differential scanning calorimetry (DSC), powder X-ray diffractometry, and polarized light microscopy (PLM). ITZ had the highest miscibility with HPMCP, being miscible at drug to polymer ratio of 6:4 (w/w). There was a downward trend of lower miscibility with Soluplus(®) (miscible at 3:7, w/w, and a few microcrystals present at 4:6, w/w), Kollidon(®) VA 64 (2:8, w/w) and Eudragit(®) E PO (<1:9, w/w). PLM was found more sensitive to detect drug crystallization than DSC and powder X-ray diffractometry. There was general correlation between results of film casting and hot-melt extrusion (HME) using a twin screw extruder. For ITZ-Soluplus(®) mixtures, HME at 4:6 (w/w) resulted in a single phase, whereas drug crystallization was observed at higher drug load. HME of ITZ-Kollidon(®) VA 64 mixtures also correlated well with the miscibility predicted by film casting. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:2142-2152, 2015. PMID:25917333

  5. High solids loading for water-based tape casting

    NASA Astrophysics Data System (ADS)

    Suwannasiri, Thitima

    Tape Casting is a low cost process for making large-area, thin, flat ceramics, which traditionally utilizes organic solvents to allow fast drying.sp{1-4} However, some of the volatile organic compounds (VOC), such as toluene, methylethyl ketone (MEK), and cyclohexanone, are hazardous air pollutants, and their emissions need to be regulated. Therefore, using water as a solvent is desirable to avoid the need of trapping VOCs. Although water is of low cost, nonflammable and safe to the environment, its heat of vaporization is high, 540 kca/g, compared to that of toluene, 74 kca/g.sp7 This makes the drying slow when water is used. The use of water in a tape casting formulation has previously been practical just for applications which require very thin tape, 100-200 mum. A high solids loading of above 50 vol% is an alternative approach to obtain sufficiently rapid drying for a thicker tape (up to 0.8 mm) since the water content is originally minimized. In order to obtain a high solids loading, the dispersants and binder systems were carefully tailored during the present research project. Low molecular weight polyelectrolytes, such as polyacrylic acid PAA (M.W. 1800) and citric acid, were found to be effective for high solids loading of Alsb2Osb3 (A-16SG), for which the electrosteric stabilization played an important role to the stability of the suspension. The viscosity and flow behavior of the suspension strongly depended on pH and the amount of polyelectrolyte, which could be related to the configuration of the polyelectrolyte molecules on the powder surface. The high solids loading of 64.5 vol% could be obtained for the fine A-16SG powder which had a surface area of 9.3 msp2/g. For the coarser powder, A-152SG, the dilatancy was a major problem that obstructed a further rise in solids loading. The dilatancy could be minimized by modifying the size distribution with A-152SG plus A-16SG and using a proper pH and amount of dispersants. An extremely high solids loading of 71-73 vol% could be reached in an aqueous system for the size-modified powder, before binder addition. An emulsion binder (Duramaxsp{TM} B-1001) aided the reduction in viscosity of the high solids loading suspension, while the soluble binder aggravated the agglomeration and drastically raised the viscosity. The emulsion binder used also had high polymer content and, therefore, less water. The final solids loadings obtained were 55.7 vol% for A-16SG and 63 vol% for mixed A-152SG and A-16SG powder. The drying time was reduced by one third for the 63 vol% formulation compared to the 55.7 vol% formulation. Water-based tape casting of A1N was possible in a buffer solution. Polyacrylic acid, PAA (M.W. 1800), aided dispersion and also minimized hydrolysis of A1N in water. Poly(vinyl pyrrolidone), PVP (M.W. 160,000), gave a lower viscosity to suspension compared to poly(vinyl alcohol) and cellulose ether, and had less bubble formation. The suspension could be processed for more than 72 h without degradation. With optimization of dispersant and binder, a high solids loading formulation of 52 vol% could be obtained. When the organic components were burned out in the air, AlN with 3wt% Ysb2Osb3 could be sintered at 1800sp°C for 1 h without degradation. The thermal conductivity was up to 153 W/m.K.

  6. Electrical Transport and Grain Growth in Solution-Cast, Chloride-Terminated Cadmium Selenide Nanocrystal Thin Films

    PubMed Central

    2015-01-01

    We report the evolution of electrical transport and grain size during the sintering of thin films spin-cast from soluble phosphine and amine-bound, chloride-terminated cadmium selenide nanocrystals. Sintering of the nanocrystals occurs in three distinct stages as the annealing temperature is increased: (1) reversible desorption of the organic ligands (?150 °C), (2) irreversible particle fusion (200–300 °C), and (3) ripening of the grains to >5 nm domains (>200 °C). Grain growth occurs at 200 °C in films with 8 atom % Cl–, while films with 3 atom % Cl– resist growth until 300 °C. Fused nanocrystalline thin films (grain size = 4.5–5.5 nm) on thermally grown silicon dioxide gate dielectrics produce field-effect transistors with electron mobilities as high as 25 cm2/(Vs) and on/off ratios of 105 with less than 0.5 V hysteresis in threshold voltage without the addition of indium. PMID:24960255

  7. Structural, absorption and optical dispersion characteristics of rhodamine B thin films prepared by drop casting technique

    NASA Astrophysics Data System (ADS)

    Farag, A. A. M.; Yahia, I. S.

    2010-11-01

    The drop casting technique has been successfully used to deposit highly uniform and good adhesion rhodamine B (Rh.B) thin films. The structural and morphological properties of Rh.B were studied by X-ray diffraction (XRD), and transmission electron microscopy (TEM), respectively. The molecular structure and electronic transitions of Rh.B were investigated by Fourier-transform infrared (FTIR) and ultraviolet-visible-near infrared (UV-VIS-NIR) spectra, respectively. The calculated Stokes shift between the excitation and emission of Rh.B reflects the displacement in potential surface between the ground and the excited states. The important absorption parameters such as molar extinction coefficient ( ?molar), the oscillator strength ( f), and the electric dipole strength ( q2) were also reported. The analysis of the spectral behavior of the absorption coefficient in the intrinsic absorption region reveals an indirect allowed transition with a band gap of 1.97 eV and associated phonons of 75 meV. The dispersion of the refractive index is discussed in terms of the single oscillator Wemple-Didomenico (WD) model. The single oscillator energy ( Eo), the dispersion energy ( Ed), the high frequency dielectric constant ( ??), the lattice dielectric constant ( ?L) and the ratio of the free charge carrier concentration to the effective mass ( N / m*) were estimated. From the optical constants analysis, the optical conductivity, volume and surface energy loss functions could also be calculated.

  8. Controlled release implants based on cast lipid blends.

    PubMed

    Kreye, F; Siepmann, F; Zimmer, A; Willart, J F; Descamps, M; Siepmann, J

    2011-05-18

    The aim of this study was to use lipid:lipid blends as matrix formers in controlled release implants. The systems were prepared by melting and casting and thoroughly characterized before and after exposure to the release medium. Based on the experimental results, a mechanistic realistic mathematical model was used to get further insight into the underlying drug release mechanisms. Importantly, broad spectra of drug release patterns could be obtained by simply varying the lipid:lipid blend ratio in implants based on Precirol ATO 5 (glyceryl palmitostearate):Dynasan 120 (hardened soybean oil) mixtures loaded with propranolol hydrochloride. Release periods ranging from a few days up to several months could be provided. Interestingly, the drug release rate monotonically decreased with increasing Dynasan 120 content, except for implants containing about 20-25% Precirol, which exhibited surprisingly high release rates. This could be attributed to the incomplete miscibility of the two lipids at these blend ratios: DSC thermograms showed phase separation in these systems. This is likely to cause differences in the implants' microstructure, which determines the mobility of water and dissolved drug as well as the mechanical stability of the systems. Purely diffusion controlled drug release was only observed at Precirol ATO 5 contents around 5-10%. In all other cases, limited drug solubility effects or matrix former erosion are also expected to play a major role. Thus, lipid:lipid blends are very interesting matrix formers in controlled release implants. However, care must be taken with respect to the mutual miscibility of the compounds: in case of phase separation, surprisingly high drug release rates might be observed. PMID:21463679

  9. Hardware-Based Ray Casting for Tetrahedral Meshes

    Microsoft Academic Search

    Manfred Weiler; Martin Kraus; Markus Merz; Thomas Ertl

    2003-01-01

    We present the first implementation of a volume ray casting algorithm for tetrahedral meshes running on off-the-shelf programmable graphics hardware. Our implementation avoids the memory transfer bottleneck of the graphics bus since the complete mesh data is stored in the local memory of the graphics adapter and all computations, in particular ray traversal and ray integration, are performed by the

  10. Rule-based quotation costing of pressure die casting moulds

    Microsoft Academic Search

    B. Denkena; L.-E. Lorenzen; J. Schürmeyer

    2009-01-01

    An actual analysis in the tool and mould making sector showed that methods and programs insufficiently support the manufacturers\\u000a of pressure die casting moulds in the quotation costing process. The primary aim of quotation costing is to generate many\\u000a first-class bids in order to gain a high quantity of profitable orders. For this purpose companies have to achieve a high

  11. Urinary casts

    MedlinePLUS

    ... Waxy casts; Casts in the urine; Fatty casts; Red blood cell casts; White blood cell casts ... by dehydration, exercise, or (water pills) diuretic medicines. Red blood cell casts are a sign of bleeding ...

  12. Spectral response of solvent-cast polyvinyl chloride (PVC) thin film used as a long-term UV dosimeter.

    PubMed

    Amar, Abdurazaq; Parisi, Alfio V

    2013-08-01

    The spectral response of solvent-cast polyvinyl chloride (PVC) thin film suitable for use as a long-term UV dosimeter has been determined by measuring the UV induced change in the 1064 cm(-1) peak intensity of the PVC's infrared (IR) spectra as a function of the wavelength of the incident radiation. Measurements using cut-off filters, narrow band-pass filters and monochromatic radiation showed that the 16 ?m PVC film responds mainly to the UVB band. The maximum response was at 290 nm and decreasing exponentially with wavelength up to about 340 nm independent of temperature and exposure dose. The most suitable concentration (W/V%) of PVC/Tetrahydrofuran solution was found to be 10% and the best thickness for the dosimeter was determined as 16 ?m. PMID:23811159

  13. High-Throughput Physiologically Based Toxicokinetic Models for ToxCast Chemicals

    EPA Science Inventory

    Physiologically based toxicokinetic (PBTK) models aid in predicting exposure doses needed to create tissue concentrations equivalent to those identified as bioactive by ToxCast. We have implemented four empirical and physiologically-based toxicokinetic (TK) models within a new R ...

  14. Integrated real time studies to track all physical and chemical changes in polyimide film processing from casting to imidization

    NASA Astrophysics Data System (ADS)

    Unsal, Emre

    Physical and chemical changes during the complex multi-step thermal imidization reaction were investigated including all processing steps (solution casting, drying and imidization), using newly developed highly instrumented measurement systems. These instruments allowed us to observe the dynamic relationship between the bound solvent evaporation that causes relaxation and chain orientation during the imidization. Drying and imidization of PMDA-ODA solutions in NMP were investigated by a novel custom designed measurement system that tracks real time weight, thickness, surface temperature, in-plane and out-of-plane birefringence. At low temperature drying stage (T < 120°C), the weight and thickness reductions occurred rapidly as a result of solvent evaporation. All the parameters started leveling off while the out of plane birefringence steadily increased and reached a plateau at longer drying times. When the temperature was increased for imidization reaction (T=200°C), additional weight loss accompanied by temporary reduction of birefringence was observed due to evaporation of bound solvent as solvent molecules decomplexed from the polymer chains and plasticized the film. During the latter stage, out-of-plane birefringence rose rapidly as the polymer chains increasingly became oriented with their chain axes were preferentially oriented in the film plane. Throughout the whole process the in-plane birefringence remained zero. For the first time, these real time measurements allowed us to quantitatively show the dynamics between chain relaxation due to evaporation of the decomplexed solvent molecules, and orientation development due to decreased chain mobility caused by imidization reaction and increasing Tg for the PMDA-ODA/NMP solutions. In addition, the dynamics of this interplay was investigated by varying the processing conditions: initial casting thickness and drying temperature. Chemical conversion, bound solvent and chain orientation that take place during thermal imidization of uniaxially constraint PMDA-ODA polyamic acid precursor film was investigated up to 200°C using real time measurement system that combines true stress, true strain, in-plane birefringence and temperature with polarized ultra-rapid scan polarized FT-IR spectrometry (URS-FT-IR). Upon heating, initially isotropic solution cast film developed stress and birefringence from the beginning while the solvent is decomplexed and evaporated. At a critical temperature (~130°C) onset of imidization reaction was observed as stress going through a maximum. Beyond this point, the evaporation and conversion took place simultaneously with steady increase in birefringence. At the end of the experiment, 80% conversion is achieved with 3% bound solvent remaining in the system.

  15. Efficacy of powder-based three-dimensional printing (3DP) technologies for rapid casting of light alloys

    Microsoft Academic Search

    Simranpreet Singh Gill; Munish Kaplas

    2011-01-01

    The aim of the present research was to compare the efficacy of two powder based 3D printing technologies for rapid casting\\u000a of light alloys. The technologies of ZCast process and investment casting were employed to cast aluminium A356 alloy and zinc\\u000a ZA-12 alloy. The split pattern shells were printed in ZCast501 powder and used directly as mould with outside sand

  16. Base of Smokestack showing brick privies and cast iron 400,000 ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Base of Smokestack showing brick privies and cast iron 400,000 gal. water tank with Roundhouse in background - Central of Georgia Railway, Savannah Repair Shops & Terminal Facilities, Combination Smokestack, Water Tank & Privies, Bounded by West Broad, Jones, West Boundary & Hull Streets, Savannah, Chatham County, GA

  17. Mechanism-based thermomechanical fatigue life prediction of cast iron. Part I: Models

    Microsoft Academic Search

    T. Seifert; H. Riedel

    2010-01-01

    In the present paper, mechanism-based models are developed to describe the time and temperature dependent cyclic plasticity and damage of cast iron materials. The cyclic plasticity model is a combination of a viscoplastic model with kinematic hardening and a porous plasticity model to take the effect of graphite inclusions into account. Thus, the model can describe creep, relaxation and the

  18. Mechanical and thermal properties of irradiated films based on Tilapia ( Oreochromis niloticus) proteins

    NASA Astrophysics Data System (ADS)

    Sabato, S. F.; Nakamurakare, N.; Sobral, P. J. A.

    2007-11-01

    Proteins are considered potential material in natural films as alternative to traditional packaging. When gamma radiation is applied to protein film forming solution it resulted in an improvement in mechanical properties of whey protein films. The objective of this work was the characterization of mechanical and thermal properties of irradiated films based on muscle proteins from Nile Tilapia ( Oreochromis niloticus). The films were prepared according to a casting technique with two levels of plasticizer: 25% and 45% glycerol and irradiated in electron accelerator type Radiation Dynamics, 0.550 MeV at dose range from 0 to 200 kGy. Thermal properties and mechanical properties were determined using a differential scanning calorimeter and a texture analyzer, respectively. Radiation from electron beam caused a slightly increase on its tensile strength characteristic at 100 kGy, while elongation value at this dose had no reduction.

  19. Photoactivated chlorophyllin-based gelatin films and coatings to prevent microbial contamination of food products.

    PubMed

    López-Carballo, G; Hernández-Muñoz, P; Gavara, R; Ocio, M J

    2008-08-15

    The aim of this work was to develop antimicrobial photosensitizer-containing edible films and coatings based on gelatin as the polymer matrix, incorporating sodium magnesium chlorophyllin (E-140) and sodium copper chlorophyllin (E-141). Chlorophyllins were incorporated into the gelatin film-forming solution and the inhibiting effect of the cast films was tested against Staphylococcus aureus and Listeria monocytogenes. The results demonstrated that water soluble sodium magnesium chlorophyllin and water soluble sodium copper chlorophyllin reduced the growth of S. aureus and L. monocytogenes by 5 log and 4 log respectively. Subsequently, the activity of self-standing films and coatings containing E-140 was assessed on cooked frankfurters inoculated with S. aureus and L. monocytogenes. These tests showed that it was possible to reduce microorganism growth in cooked frankfurters inoculated with S. aureus and L. monocytogenes by covering them with sodium magnesium chlorophyllin-gelatin films and coatings. PMID:18555550

  20. Evaluation of an improved centrifugal casting machine.

    PubMed

    Donovan, T E; White, L E

    1985-05-01

    A Type III gold alloy, a silver-palladium alloy, and a base metal alloy were cast in two different centrifugal casting machines. With the number of complete cast mesh squares as an indicator of castability, the Airspin casting machine produced superior castings with all three alloys. The base metal alloy produced the greatest number of complete squares with both casting machines. PMID:3889295

  1. Caste- and ethnicity-based inequalities in HIV/AIDS-related knowledge gap: a case of Nepal.

    PubMed

    Atteraya, Madhu; Kimm, HeeJin; Song, In Han

    2015-05-01

    Caste- and ethnicity-based inequalities are major obstacles to achieving health equity. The authors investigated whether there is any association between caste- and ethnicity-based inequalities and HIV-related knowledge within caste and ethnic populations. They used the 2011 Nepal Demographic and Health Survey, a nationally represented cross-sectional study data set. The study sample consisted of 11,273 women between 15 and 49 years of age. Univariate and logistic regression models were used to examine the relationship between caste- and ethnicity-based inequalities and HIV-related knowledge. The study sample was divided into high Hindu caste (47.9 percent), "untouchable" caste (18.4 percent), and indigenous populations (33.7 percent). Within the study sample, the high-caste population was found to have the greatest knowledge of the means by which HIV is prevented and transmitted. After controlling for socioeconomic and demographic characteristics, untouchables were the least knowledgeable. The odds ratio for incomplete knowledge about transmission among indigenous populations was 1.27 times higher than that for high Hindu castes, but there was no significant difference in knowledge of preventive measures. The findings suggest the existence of a prevailing HIV knowledge gap. This in turn suggests that appropriate steps need to be implemented to convey complete knowledge to underprivileged populations. PMID:26027418

  2. The physical properties and response of osteoblasts to solution cast films of PLGA doped polycaprolactone.

    PubMed

    Tang, Z G; Callaghan, J T; Hunt, J A

    2005-11-01

    Polycaprolactone films doped with poly(lactide-co-glycolide) (65:35) in 0, 10, 20, and 30 (wt%) were prepared and evaluated in terms of morphology, dynamic contact angle analysis, and thermal properties. The unique surface morphology of the doped PCL film resulted, without introducing significant microstructure disruption of PCL aggregation. The doped PCL film registered a lower contact angle and increased hydrophilicity. Osteoblast cells attached to all doped materials, the 10% and 20% doped materials demonstrating the greatest cell growth. PMID:15935466

  3. Mechanical and structural properties of solution-cast high-amylose maize starch films.

    PubMed

    Koch, Kristine; Gillgren, Thomas; Stading, Mats; Andersson, Roger

    2010-01-01

    Environmental issues have forced the introduction of sustainable solutions such as annually renewable resources being used as a raw material for packaging and disposables. This paper examined the effects of time and temperature during manufacturing and plasticiser content on the molecular structure of high-amylose maize starch films. It also analysed how manufacturing conditions, plasticiser content and molecular structure of the films affected their material properties. It was found that increased time or temperature increased the degradation of amylose and of amylopectin, which in turn negatively affected film cohesiveness. However, neither time nor temperature had any effect on tensile properties. PMID:19828118

  4. Modeling and analysis of film composition on mechanical properties of maize starch based edible films.

    PubMed

    Prakash Maran, J; Sivakumar, V; Thirugnanasambandham, K; Kandasamy, S

    2013-11-01

    The present study investigates the influence of composition (content of maize starch (1-3 g), sorbitol (0.5-1.0 ml), agar (0.5-1.0 g) and tween-80 (0.1-0.5 ml)) on the mechanical properties (tensile strength, elongation, Young's modulus, puncture force and puncture deformation) of the maize starch based edible films using four factors with three level Box-Behnken design. The edible films were obtained by casting method. The results showed that, tween-80 increases the permeation of sorbitol in to the polymer matrix. Increasing concentration of sorbitol (hydrophilic nature and plasticizing effect of sorbitol) decreases the tensile strength, Young's modulus and puncture force of the films. The results were analyzed by Pareto analysis of variance (ANOVA) and second order polynomial models were obtained for all responses with high R(2) values (R(2)>0.95). 3D response surface plots were constructed to study the relationship between process variables and the responses. PMID:24080451

  5. Crosslinked superhydrophobic films fabricated by simply casting poly(methyl methacrylate-butyl acrylate-hydroxyethyl methacrylate)-b-poly(perfluorohexylethyl methacrylate) solution

    NASA Astrophysics Data System (ADS)

    Wen, Xiufang; Ye, Chao; Cai, Zhiqi; Xu, Shouping; Pi, Pihui; Cheng, Jiang; Zhang, Lijuan; Qian, Yu

    2015-06-01

    This study focuses on the preparation of superhydrophobic films by crosslinkable polymer material-Poly(methyl methacrylate-butyl acrylate-hydroxyethyl methacrylate)-b-Poly(perfluorohexylethyl methacrylate) (P (MMA-BA-HEMA)-b-PFMA) with a simple one-step casting process. Nanoscale micelle particles with core-shell structure was obtained by dissolving the polymer and curing agent in the mixture of acetone and 1H, 1H, 5H octafluoropentyl-1,1,2,2 tetrafluoroethyl ether (FHT). Superhydrophobic films were fabricated by casting the micelle solution on the glass slides. By controlling the polymer concentration and acetone/FHT volume ratio, superhydrophobic polymer film with water contact angle of 153.2 ± 2.1° and sliding angle of 4° was obtained. By introducing a curing agent into the micelle solution, mechanical properties of the films can be improved. The adhension grade and hardness of the crosslinked superhydrophobic films reached 2 grade and 3H, respectively. The hydrophobicity is attributed to the synergistic effect of micro-submicro-nano-meter scale roughness by nanoscale micelle particles and low surface energy of fluoropolymer. This procedure makes it possible for widespread applications of superhydrophobic film due to its simplicity and practicability.

  6. Method of improving fatigue life of cast nickel based superalloys and composition

    Microsoft Academic Search

    Allen F. Denzine; Thomas A. Kolakowski; John F. Wallace

    1978-01-01

    The invention consists of a method of producing a fine equiaxed grain structure (ASTM 2-4) in cast nickel-base superalloys which increases low cycle fatigue lives without detrimental effects on stress rupture properties to temperatures as high as 1800.degree. F. These superalloys are variations of the basic nickel-chromium matrix, hardened by gamma prime [Ni.sub.3 (Al, Ti)] but with optional additions of

  7. Thermomechanical fatigue behavior and life prediction of a cast nickel-based superalloy

    Microsoft Academic Search

    Z. W. Huang; Z. G. Wang; S. J. Zhu; F. H. Yuan; F. G. Wang

    2006-01-01

    The cyclic deformation and lifetime behavior of a cast nickel-based superalloy M963 was investigated under both thermomechanical fatigue (TMF) and isothermal fatigue (IF) conditions. Two types of TMF tests, i.e. in-phase (IP) and out-of-phase (OP), were performed in temperature range of 450–900°C, and IF tests were conducted at a temperature of 900°C. All tests were carried out under mechanical strain

  8. Biocomposite films based on alginate and organically modified clay.

    PubMed

    Tezcan, Filiz; Günister, Ebru; Ozen, Gönül; Erim, F Bedia

    2012-05-01

    Sodium alginate/sodium montmorillonite hybrid films were prepared by casting from the suspension of sodium alginate and different clay samples. Clay samples had been modified with a cationic surfactant, a cationic polymer, and a small polar molecule, respectively. Benzethonium chloride, polyethyleneimine and urea were used as clay modifiers. The composite films begin to disintegrate at a higher temperature and with less weight loss than the pure alginate films. This suggests an enhancement of the film thermal stability due to the modification of the alginate with clay samples. PMID:22269346

  9. Project CAST.

    ERIC Educational Resources Information Center

    Charles County Board of Education, La Plata, MD. Office of Special Education.

    The document outlines procedures for implementing Project CAST (Community and School Together), a community-based career education program for secondary special education students in Charles County, Maryland. Initial sections discuss the role of a learning coordinator, (including relevant travel reimbursement and mileage forms) and an overview of…

  10. Influence of Molecular Rigidity on Interfacial Ordering in Diphenyl-Based Polysiloxane Films

    SciTech Connect

    Evmenenko,G.; Kewalramani, S.; Dutta, P.

    2007-01-01

    Synchrotron X-ray reflectivity (XRR) shows significant differences between the ordering in thin films of diphenyl-based siloxane oligomers with single versus double backbones of -Si-O- repeating groups. We show that the more restricted conformational arrangement of twofold-skeleton molecules results in a higher degree of molecular ordering indicated by 2-2.5 times higher value of intensity of the corresponding Bragg peak in thin solid films of poly(phenylsilsesquioxane) than in films of poly(diphenylsiloxane), regardless of the solvent used for film casting. In both cases, the ordered molecules are located within 40-50 Angstroms of the substrate surface. The results indicate unambiguously that the chain stiffness of siloxanes governs the degree of ordering in the restricted geometry of the interfacial region.

  11. LineCast: line-based distributed coding and transmission for broadcasting satellite images.

    PubMed

    Wu, Feng; Peng, Xiulian; Xu, Jizheng

    2014-03-01

    In this paper, we propose a novel coding and transmission scheme, called LineCast, for broadcasting satellite images to a large number of receivers. The proposed LineCast matches perfectly with the line scanning cameras that are widely adopted in orbit satellites to capture high-resolution images. On the sender side, each captured line is immediately compressed by a transform-domain scalar modulo quantization. Without syndrome coding, the transmission power is directly allocated to quantized coefficients by scaling the coefficients according to their distributions. Finally, the scaled coefficients are transmitted over a dense constellation. This line-based distributed scheme features low delay, low memory cost, and low complexity. On the receiver side, our proposed line-based prediction is used to generate side information from previously decoded lines, which fully utilizes the correlation among lines. The quantized coefficients are decoded by the linear least square estimator from the received data. The image line is then reconstructed by the scalar modulo dequantization using the generated side information. Since there is neither syndrome coding nor channel coding, the proposed LineCast can make a large number of receivers reach the qualities matching their channel conditions. Our theoretical analysis shows that the proposed LineCast can achieve Shannon's optimum performance by using a high-dimensional modulo-lattice quantization. Experiments on satellite images demonstrate that it achieves up to 1.9-dB gain over the state-of-the-art 2D broadcasting scheme and a gain of more than 5 dB over JPEG 2000 with forward error correction. PMID:24474371

  12. Spin-cast P(VDF-TrFE) films for high performance medical ultrasound transducers

    Microsoft Academic Search

    L. F. Brown; R. L. Carlson; J. M. Sempsrott

    1997-01-01

    Ferroelectric polymers are used in many special medical and industrial ultrasonic transducer applications. In most of these applications a free-standing metallized (i.e., patterned) film is adhered to a substrate material which is either reflective (i.e., high acoustic impedance) or acoustically matched in impedance but highly lossy. The adhesive layer can have adverse effects on ultrasonic transducer performance, especially at high

  13. The caste based mosaic of Indian politics C H R I S T O P H E J A F FR E L O T

    E-print Network

    Boyer, Edmond

    The caste based mosaic of Indian politics C H R I S T O P H E J A F FR E L O T WHILE caste politics voters, are associated with a single caste and/or religious community ­ and this is also true of some that this redrawing of the frontiers of the state in large part stemmed from the demands of dominant castes. In 1947

  14. Effect of carboxymethyl cellulose concentration on physical properties of biodegradable cassava starch-based films

    PubMed Central

    2011-01-01

    Background Cassava starch, the economically important agricultural commodity in Thailand, can readily be cast into films. However, the cassava starch film is brittle and weak, leading to inadequate mechanical properties. The properties of starch film can be improved by adding plasticizers and blending with the other biopolymers. Results Cassava starch (5%w/v) based films plasticized with glycerol (30 g/100 g starch) were characterized with respect to the effect of carboxymethyl cellulose (CMC) concentrations (0, 10, 20, 30 and 40%w/w total solid) and relative humidity (34 and 54%RH) on the mechanical properties of the films. Additionally, intermolecular interactions were determined by Fourier transform infrared spectroscopy (FT-IR), melting temperature by differential scanning calorimetry (DSC), and morphology by scanning electron microscopy (SEM). Water solubility of the films was also determined. Increasing concentration of CMC increased tensile strength, reduced elongation at break, and decreased water solubility of the blended films. FT-IR spectra indicated intermolecular interactions between cassava starch and CMC in blended films by shifting of carboxyl (C = O) and OH groups. DSC thermograms and SEM micrographs confirmed homogeneity of cassava starch-CMC films. Conclusion The addition of CMC to the cassava starch films increased tensile strength and reduced elongation at break of the blended films. This was ascribed to the good interaction between cassava starch and CMC. Cassava starch-CMC composite films have the potential to replace conventional packaging, and the films developed in this work are suggested to be suitable for low moisture food and pharmaceutical products. PMID:21306655

  15. Corrosion behavior of cast and forged cobalt-based alloys for double-alloy joint endoprostheses.

    PubMed

    Süry, P; Semlitsch, M

    1978-09-01

    An ideal combination of mechanical and corrosion properties of long-term implants such as joint endoprostheses has yet to be found. Besides being resistant to pitting and crevice attack, which can lead to corrosion fatigue and stress corrosion cracking failures, the implant material must be highly resistant to wear and abrasion. Two cobalt-based alloys, wrought CoNiMoTi and air-cast CoCrMo, were subjected to a number of selected in vitro electrochemically and chemically accelerated corrosion tests in chloride-containing solutions with wrought AISI-316L used as a reference alloy. A limited number of immersion tests in FeCl3 and acidified FeCl3 solutions were also conducted. It is found that the mechanical properties of wrought CoNiCrMoTi alloy qualify it as a substitute for cast CoCrMo alloy and wrought AISI-316L in anchorage shaft production for all types of joint endoprostheses. Wrought CoNiCrMoTi has a higher resistance to fatigue cracking compared with cast CoCrMo and is as resistant to selective corrosion phenomena such as stress corrosion cracking. PMID:701305

  16. Precipitation Strengthening of a Mg-Al-Ca Based AXJ530 Die-cast Alloy

    NASA Astrophysics Data System (ADS)

    Suzuki, A.; Saddock, N. D.; Terbush, J. R.; Powell, B. R.; Jones, J. W.; Pollock, T. M.

    2008-03-01

    Precipitation of the Al2Ca phase in the ?-Mg phase of the Mg-Al-Ca based AXJ530 die-cast alloy and the effect of precipitation hardening on the creep resistance were studied. Precipitation of the Al2Ca phase is suppressed in the die-casting process due to its high cooling rate, but precipitation was observed during subsequent isothermal heat treatments above 448 K. The precipitate has a disk-shaped morphology parallel to the basal plane of the ?-Mg matrix phase and increases hardness by aging in the temperature range of 448 to 573 K. The creep resistance of the die-cast material at 448 K was improved by a factor of 1.5 ˜ 2, by a peak-age heat treatment at 523 K for 1 hour. Improvement in strength is limited by the low volume fraction of the precipitates; however, the precipitates are effective obstacles against dislocations gliding on nonbasal planes during creep deformation.

  17. Improvement of the mechanical and barrier properties of methylcellulose-based films by treatment with HEMA and silane monomers under gamma radiation

    NASA Astrophysics Data System (ADS)

    Khan, Ruhul A.; Dussault, Dominic; Salmieri, Stephane; Safrany, Agnes; Lacroix, Monique

    2012-08-01

    Methylcellulose (MC)-based films were prepared by casting from its 1% aqueous solution containing 0.5% vegetable oil, 0.25% glycerol and 0.025% Tween®-80. Puncture strength (PS), puncture deformation (PD) and water vapor permeability (WVP) of the films were found to be 147 N/mm, 3.46 mm, and 6.34 g mm/m2 day kPa, respectively. The monomer, 2-hydroxyethyl methacrylate (HEMA) (0.1-1%, w/w) was incorporated into the MC-based solution and films were prepared by casting. Films were then exposed to gamma radiation (5-25 kGy) and it revealed that 1% HEMA containing films showed the highest PS values (282 N/mm at 10 kGy). Silane monomer (3-aminopropyl tri-ethoxy silane) (0.1-1%, w/w) was also added into the MC-based films and were found to improve the strength of the films significantly. In comparison between HEMA and silane treatment onto MC-based films, it was observed that silane performed better strength and barrier properties. Surface morphology of the monomer treated films was examined by scanning electron microscopy and suggested better appearance than MC-based film.

  18. Multifractal characterization of water soluble copper phthalocyanine based films surfaces

    NASA Astrophysics Data System (ADS)

    ??lu, ?tefan; Stach, Sebastian; Mahajan, Aman; Pathak, Dinesh; Wagner, Tomas; Kumar, Anshul; Bedi, R. K.; ??lu, Mihai

    2014-07-01

    This paper presents a multifractal approach to characterize the structural complexity of 3D surface roughness of CuTsPc films on the glass and quartz substrate, obtained with atomic force microscopy (AFM) analysis. CuTsPc films prepared by drop cast method were investigated. CuTsPc films surface roughness was studied by AFM in tapping-mode™, in an aqueous environment, on square areas of 100 ?m2 and 2500 ?m2. A detailed methodology for CuTsPc films surface multifractal characterization, which may be applied for AFM data, was also presented. Analysis of surface roughness revealed that CuTsPc films have a multifractal geometry at various magnifications. The generalized dimension D q and the singularity spectrum f( ?) provided quantitative values that characterize the local scale properties of CuTsPc films surface morphology at nanometer scale. Multifractal analysis provides different yet complementary information to that offered by traditional surface statistical parameters.

  19. Microelectromechanical systems based on ferroelectric thin films

    Microsoft Academic Search

    Dennis L. Polla

    1995-01-01

    Ferroelectric thin films have been integrated in silicon-based microelectromechanical systems, commonly called MEMS. Several thin films of the PZT family have been used in the formation of both microsensors and microactuators in processes compatible with 2-?m analog CMOS technology. Ferroelectric MEMS offer significant advantages of high signal-to-noise, low power dissipation, and high force generation in comparison to other MEMS technologies

  20. Improved material properties of solution-cast starch films: Effect of varying amylopectin structure and amylose content of starch from genetically modified potatoes.

    PubMed

    Menzel, Carolin; Andersson, Mariette; Andersson, Roger; Vázquez-Gutiérrez, José L; Daniel, Geoffrey; Langton, Maud; Gällstedt, Mikael; Koch, Kristine

    2015-10-01

    High-amylose potato starches were produced through genetic modification resulting in changed granule morphology and composition, with higher amylose content and increased chain length of amylopectin. The increased amylose content and structural changes in amylopectin enhanced film-forming behavior and improved barrier and tensile properties in starch films. The molecular structure in these starches was related to film-forming properties. Solution-cast films of high-amylose starch revealed a homogeneous structure with increasing surface roughness at higher amylose content, possibly due to amylose aggregation. Films exhibited significantly higher stress and strain at break compared with films of wild-type starch, which could be attributable to the longer chains of amylopectin being involved in the interconnected network and more interaction between chains, as shown using transmission electron microscopy. The oxygen permeability of high-amylose starch films was significantly decreased compared with wild-type starch. The nature of the modified starches makes them an interesting candidate for replacement of non-renewable oxygen and grease barrier polymers used today. PMID:26076640

  1. Simple casting based fabrication of PEDOT:PSS-PVDF-ionic liquid soft actuators

    NASA Astrophysics Data System (ADS)

    Simaite, Aiva; Tondu, Bertrand; Mathieu, Fabrice; Souéres, Philippe; Bergaud, Christian

    2015-04-01

    Despite a growing interest in conducting polymer based actuators, a robust fabrication technique is still needed. We suggest a fabrication method that allows fast production of conducting polymer actuators from commercially available polyvinylidene flouride membranes (PVDF) and a PEDOT/PSS solution. In order to improve adhesion of those materials, Ar plasma induced grafting is used to create hydrophilic surfaces of up to 40 ?m. Hydrophilic PVDF-graft-polyethylene glycol allows diffusion of PEDOT/PSS in the pores of the membranes, while hydrophobic middle layers prevent short circuits. In this way, soft actuators can be fabricated by consequent drop casting and drying of conducting polymer.

  2. Layer bonding of solvent-cast thin films for pharmaceutical solid dosage forms

    E-print Network

    Kim, Won, S.M. Massachusetts Institute of Technology

    2010-01-01

    In the pharmaceutical industry, the conventional tablet manufacturing process, a batch-based process based on solid powder handling, presents challenges such as inhomogeneous blending between Active Pharmaceutical Ingredients ...

  3. Numerical simulation of off-centred porosity formation of TiAl-based alloy exhaust valve during vertical centrifugal casting

    NASA Astrophysics Data System (ADS)

    Shiping, Wu; Jingjie, Guo; Yanqing, Su; Chengzhi, Zhao; Jun, Jia

    2003-07-01

    The vertical centrifugal casting method has been used to cast a TiAl-based alloy exhaust valve. Although mould filling and solidification of TiAl-based alloy melt proceed under pressure generated by the centrifugal force, an unfavourable solidification sequence is formed because of the special mould filling mode and finally results in the formation of off-centred porosity. Numerical simulation is applied to study the vertical centrifugal casting process of the TiAl-based alloy exhaust valve in this paper. On the basis of simulations of the flow field and the temperature field, the law of porosity formation during the vertical centrifugal casting of the TiAl-based alloy exhaust valve is discussed by analysing the mould filling and solidification process. The results of the numerical simulation show that off-centred porosity forms easily near the entrance of the cast product and the tendency for off-centred porosity formation decreases with increasing distance from the entrance to the far end. The experimental results agree well with those of the numerical simulation.

  4. Microstructure-based fatigue life prediction for cast A356-T6 aluminum-silicon alloys

    NASA Astrophysics Data System (ADS)

    Yi, J. Z.; Gao, Y. X.; Lee, P. D.; Lindley, T. C.

    2006-04-01

    Fatigue life prediction and optimization is becoming a critical issue affecting the structural applications of cast aluminum-silicon alloys in the aerospace and automobile industries. In this study, a range of microstructure and porosity populations in A356 alloy was created by controlling the casting conditions and by applying a subsequent hot isostatic pressing (“hipping”) treatment. The microstructure and defects introduced during the processing were then quantitatively characterized, and their effects on the fatigue performance were examined through both experiment and modeling. The results indicated that whenever a pore is present at or near the surface, it initiates fatigue failure. In the absence of large pores, a microcell consisting of ?-Al dendrites and associated Si particles was found to be responsible for crack initiation. Crack initiation life was quantitatively assessed using a local plastic strain accumulation model. Moreover, the subsequent crack growth from either a pore or a microcell was found to follow a small-crack propagation law. Based on experimental observation and finite-element analysis, a unified model incorporating both the initiation and small crack growth stages was developed to quantitatively predict the dependency of fatigue life on the microstructure and porosity. Good agreement was obtained between the model and experiment.

  5. A comparative study of oxidation and hot corrosion of a cast nickel base superalloy in different corrosive environments

    Microsoft Academic Search

    D. Deb; S. Ramakrishna Iyer; V. M. Radhakrishnan

    1996-01-01

    Oxidation and hot corrosion in sulphate, chloride and vanadate environment of a cast nickel base superalloy are discussed. Weight gain studies are carried out in air for the uncoated and coated samples. The corrosion products are analysed and the possible mechanisms of corrosion based on the corrosion compounds are discussed. The variation of weight gain with time indicated a parabolic

  6. [Experimental studies of casting contraction of crowns and bridges made of various alloys based on nickel (NI-CR)].

    PubMed

    Dobies, K; Gehre, G; Bién, D; Fechler, M

    1990-01-01

    The results are presented of experimental studies of casting contraction of metal crowns and bridges with an attempt at outlining of practical suggestions concerning the choice of materials and work technology with alloys based on nickel. Casting contraction was determined for the following alloys: Gisadent MCA, Gisadent NCS1, Mikrostom-1 and Wiron-88. The need for further studies on alloys based on nickel which may be used for preparation of permanent replacements as substitutes of precious metals is caused in Poland and all over the world by economic factors. PMID:2103044

  7. Context-based user grouping for multi-casting in heterogeneous radio networks

    NASA Astrophysics Data System (ADS)

    Mannweiler, C.; Klein, A.; Schneider, J.; Schotten, H. D.

    2011-08-01

    Along with the rise of sophisticated smartphones and smart spaces, the availability of both static and dynamic context information has steadily been increasing in recent years. Due to the popularity of social networks, these data are complemented by profile information about individual users. Making use of this information by classifying users in wireless networks enables targeted content and advertisement delivery as well as optimizing network resources, in particular bandwidth utilization, by facilitating group-based multi-casting. In this paper, we present the design and implementation of a web service for advanced user classification based on user, network, and environmental context information. The service employs simple and advanced clustering algorithms for forming classes of users. Available service functionalities include group formation, context-aware adaptation, and deletion as well as the exposure of group characteristics. Moreover, the results of a performance evaluation, where the service has been integrated in a simulator modeling user behavior in heterogeneous wireless systems, are presented.

  8. The research and development of CCD-based slab continuous casting mold copper surface imaging system

    NASA Astrophysics Data System (ADS)

    Wang, Xingdong; Zhang, Liugang; Xie, Haihua; Long, Liaosha; Yu, Wenyong

    2011-11-01

    An imaging system for the continuous casting mold copper surface is researched and developed, to replace the on-line manual measuring method, which is used to checking Copper defects such as wearing, scratches and coating loss and other phenomena. Method: The imaging system proposes a special optical loop formed by three Mirrors, selects light source, CCD camera and lens type, designs mechanical transmission system and installation platform. Result: the optical loop and light source can insure imaging large-format object in narrow space. The CCD camera and lens determine the accuracy of horizontal scanning, and the mechanical transmission system ensures accuracy of the vertical scan. The installation platform supplies base and platform for the system. Conclusions: CCD-based copper surface imaging system effectively prevent defects such as missed measuring and low efficiency, etc. It can automatically and accurately shoot copper surface images on-line, and supply basis for image processing, defects identification and copper changing in the late.

  9. 2005 May JOM 29 Casting DefectsOverview

    E-print Network

    Beckermann, Christoph

    2005 May · JOM 29 Casting DefectsOverview Casting designs are generally based factors of safety, which leadtoincreasedcomponentweightsand inefficient use of materials. In castings in castings and determine their effect on performance. INTRODUCTION Designers are responsible for the per

  10. [Flow of molten metal in denture base in horizontal centrifugal casting procedure. (Part 2) Flow, inflow volume and casting time of molten metal passing through several sprues into model denture plate mold (author's transl)].

    PubMed

    Okamura, H

    1978-10-01

    Two types of spruing methods were used in the casting of the denture type model pattern (thickness, 0.43 mm). Flow of molten metal in the mold was filmed by the improved system of Part 1. When three sprues were attached to the pattern vertically, molten metal passed through each sprue gate flowed being affected by the direction of gravity and revolution of casting machine, and gathered at the lower part of the mold. Next molten metal filled the mold from the lower part to the upper part. In this spruing type, molten metal turned its direction of flow several times. At the middle stage of casting, the inflow volume per unit time (inflow rate), v (mm3/10-2)s)was evaluated as v = 12.36 + 5.16A-0.16 A2 (A: total cross-sectional areas of sprues). The inflow rate increased with increase of the area of the sprues, but it saturated. When the main sprue and the subsprues were attached at the posterior border, the molten metal filled the mold from the lower part to the upper part quietly. In this spruing type, the casting mold was set facing its sprue gates downwards. The inflow rate at the middle stage of casting was evaluated as v = 21.05 + 1.79 C (C: the cross-sectional area of the main sprue). The inflow rate increased linearly with increase of the area of the main sprue. PMID:392022

  11. Combining color-based invariant gradient detector with HoG descriptors for robust image detection in scenes under cast shadows

    Microsoft Academic Search

    Michael Villamizar; Jorge Scandaliaris; Alberto Sanfeliu; Juan Andrade-cetto

    2009-01-01

    In this work we present a robust detection method in outdoor scenes under cast shadows using color based invariant gradients in combination with HoG local features. The method achieves good detection rates in urban scene classification and person detection outperforming traditional methods based on intensity gradient detectors which are sensible to illumination variations but not to cast shadows. The method

  12. Development of NZP ceramic based {open_quotes}cast-in-place{close_quotes} diesel engine port liners

    SciTech Connect

    Nagaswaran, R.; Limaye, S.Y.

    1996-02-01

    BSX (Ba{sub 1+x}Zr{sub 4}P{sub 6-2x}Si{sub 2x}O{sub 24}) and CSX (Ca{sub l-x}Sr{sub x}Zr{sub 4}P{sub 6}O{sub 24}) type NZP ceramics were fabricated and characterized for: (i) thermal properties viz., thermal conductivity, thermal expansion, thermal stability and thermal shock resistance; (ii) mechanical properties viz., flexure strength and elastic modulus; and (iii) microstructures. Results of these tests and analysis indicated that the BS-25 (x=0.25 in BSX) and CS-50 (x=0.50 in CSX) ceramics had the most desirable properties for casting metal with ceramic in place. Finite element analysis (FEA) of metal casting (with ceramic in place) was conducted to analyze thermomechanical stresses generated and determine material property requirements. Actual metal casting trials were also conducted to verify the results of finite element analysis. In initial trials, the ceramic cracked because of the large thermal expansion mismatch (hoop) stresses (predicted by FEA also). A process for introduction of a compliant layer between the metal and ceramic to alleviate such destructive stresses was developed. The compliant layer was successful in preventing cracking of either the ceramic or the metal. In addition to these achievements, pressure slip casting and gel-casting processes for fabrication of NZP components; and acoustic emission and ultrasonics-based NDE techniques for detection of microcracks and internal flaws, respectively, were successfully developed.

  13. Fracture and fatigue of cast gamma TiAl based aluminides

    SciTech Connect

    Bowen, P.; Rogers, N.J.; James, A.W. [Univ. of Birmingham (United Kingdom)

    1995-12-31

    This paper considers the crack growth resistance of cast and heat-treated gamma TiAl based aluminides under both monotonic and cyclic loading. Attention is focused primarily on the crack growth resistance of fatigue pre-cracked test pieces, and the influence of test temperature, microstructure and lamellar colony orientation is highlighted. Particular emphasis throughout this paper is placed on fully lamellar and near (fully) lamellar microstructures. The importance of aligned lamellar colonies and randomized lamellar colonies on fracture toughness and fatigue crack growth resistance is illustrated. Finally, the effects of the size of the lamellar colonies on fracture toughness and its interpretation is addressed, and especially with respect to the amount of material sampled within the process zone ahead of the sharp fatigue pre-crack tip.

  14. The Physical-Mechanical and Electrical Properties of Cast Aluminum-Based Alloys Reinforced with Diamond Nanoparticles

    NASA Astrophysics Data System (ADS)

    Vorozhtsov, S. A.; Khrustalyov, A. P.; Eskin, D. G.; Kulkov, S. N.; Alba-Baena, N.

    2015-03-01

    The results obtained from investigations into the microstructure and physical-mechanical and electrical properties of cast aluminum-based alloys reinforced with nanodiamonds are presented. Addition of the diamond nanoparticles is shown to change the structural parameters and improve the mechanical properties of the materials.

  15. High Throughput Prioritization for Integrated Toxicity Testing Based on ToxCast Chemical Profiling

    EPA Science Inventory

    The rational prioritization of chemicals for integrated toxicity testing is a central goal of the U.S. EPA?s ToxCast? program (http://epa.gov/ncct/toxcast/). ToxCast includes a wide-ranging battery of over 500 in vitro high-throughput screening assays which in Phase I was used to...

  16. Effect of nickel-based dental casting alloys on fibroblast metabolism and ultrastructural organization.

    PubMed

    Bumgardner, J D; Doeller, J; Lucas, L C

    1995-05-01

    Previous cell culture evaluations have shown that nickel-chromium dental alloys did not affect cellular viability or morphology. However, nickel-based alloys released corrosion products which decreased cellular proliferation. It was hypothesized that this decrease was due to an interference of cellular energy metabolism by released metal ions. To test this hypothesis, we evaluated the effects on cellular energy metabolism, adenosine triphosphate (ATP) levels, and cellular ultrastructure by four nickel-based alloys, including high and low chromium alloys with and without beryllium additions, in human gingival fibroblast cell cultures. Energy metabolism was evaluated by measuring glucose-6-phosphate dehydrogenase (G-6-PDH) activity. ATP levels were measured with the luciferin-luciferase method. Cellular membranes and ultrastructural organization were evaluated by scanning and transmission electron microscopy. The results of this study showed that metal ions released from all alloys completely inhibited G-6-PDH activity and reduced cellular ATP levels as compared to controls. The reduction in intracellular ATP was greater for the beryllium containing alloys than the non-beryllium-containing alloys. However, no morphologic changes in cellular membranes or organelles were observed. These results support the hypothesis that metal ions released from nickel-based dental casting alloys interfere with cellular energy metabolism. PMID:7622546

  17. Polyelectrolyte films based on chitosan/olive oil and reinforced with cellulose nanocrystals.

    PubMed

    Pereda, Mariana; Dufresne, Alain; Aranguren, Mirta I; Marcovich, Norma E

    2014-01-30

    Composite films designed as potentially edible food packaging were prepared by casting film-forming emulsions based on chitosan/glycerol/olive oil containing dispersed cellulose nanocrystals (CNs). The combined use of cellulose nanoparticles and olive oil proved to be an efficient method to reduce the inherently high water vapor permeability of plasticized chitosan films, improving at the same time their tensile behavior. At the same time, it was found that the water solubility slightly decreased as the cellulose content increased, and further decreased with oil addition. Unexpectedly, opacity decreased as cellulose content increased, which balanced the reduced transparency due to lipid addition. Contact angle decreased with CN addition, but increased when olive oil was incorporated. Results from dynamic mechanical tests revealed that all films present two main relaxations that could be ascribed to the glycerol- and chitosan-rich phases, respectively. The response of plasticized chitosan-nanocellulose films (without lipid addition) was also investigated, in order to facilitate the understanding of the effect of both additives. PMID:24299870

  18. Preparation and characterization of bionanocomposite films based on potato starch/halloysite nanoclay.

    PubMed

    Sadegh-Hassani, Fatemeh; Mohammadi Nafchi, Abdorreza

    2014-06-01

    In this research casting method was used to prepare potato starch based bio-nanocomposite films with halloysite nanoclay as the reinforcing materials. The composition included potato starch with 40% (w/w) of a mixture of sorbitol/glycerol (weight ratio of 3 to 1as plasticizer) with nanoclay (0-5% w/w). The films were dried under controlled conditions. Physicochemical properties such as solubility in water, water absorption capacity (WAC), water vapour permeability (WVP), oxygen permeability, and mechanical properties of the films were measured. Results showed that by increasing the concentration of nanoclay, mechanical properties of films were improved. Tensile strength was increased from 7.33 to 9.82MPa, and elongation at break decreased from 68.0 to 44.0%. Solubility in water decreased from 35 to 23%, and heat seal strength increased from 375 to 580N/m. Also incorporation of clay nanoparticles in the structure of biopolymer decreased permeability of the gaseous molecules. In summary, addition of halloysite nanoclay, improve the barrier and mechanical properties of potato starch films and this bionanocomposites have high potential to be used for food packaging purposes. PMID:24747380

  19. A comparative study on microgap of premade abutments and abutments cast in base metal alloys.

    PubMed

    Lalithamma, Jaini Jaini; Mallan, Sreekanth Anantha; Murukan, Pazhani Appan; Zarina, Rita

    2014-06-01

    The study compared the marginal accuracy of premade and cast abutments. Premade titanium, stainless steel, and gold abutments formed the control groups. Plastic abutments were cast in nickel-chromium, cobalt-chromium and grade IV titanium. The abutment/implant interface was analyzed. Analysis of variance and Duncan's multiple range test revealed no significant difference in mean marginal microgap between premade gold and titanium abutments and between premade stainless steel and cast titanium abutments. Statistically significant differences (P < .001) were found among all other groups. PMID:24914909

  20. Oral keratinocyte responses to nickel-based dental casting alloys in vitro.

    PubMed

    Wylie, C M; Davenport, A J; Cooper, P R; Shelton, R M

    2010-09-01

    Adverse reactions of oral mucosa to nickel-based dental casting alloys are probably due to corrosion metal ion release. We exposed H400 oral keratinocytes to two Ni-based dental alloys (Matchmate and Dsign10) as well as NiCl( 2) (1-40 microg/mL Ni(2+)). Alloy derived Ni(2+) media concentrations were determined. Direct culture on both alloys resulted in inhibited growth with a greater effect observed for Dsign10 (higher ion release). Indirect exposure of cells to conditioned media from Dsign10 negatively affected cell numbers (approximately 64% of control by 6 days) and morphology while Matchmate-derived media did not. Exposure to increasing NiCl(2) negatively affected cell growth and morphology, and the Granulocyte-macrophage colony-stimulating factor (GM-CSF) transcript was significantly up-regulated in cells following direct and indirect exposure to Dsign10. NiCl(2) exposure up-regulated all cytokine transcripts at 1 day. At day 6, IL-1beta and IL-8 transcripts were suppressed while GM-CSF and IL-11 increased with Ni(2+) dose. Accumulation of Ni(2+) ions from alloys in oral tissues may affect keratinocyte viability and chronic inflammation. PMID:20008086

  1. Thermal stability and glass forming ability of cast iron based CiPxB4.35 bulk amorphous alloys

    NASA Astrophysics Data System (ADS)

    Shapaan, M.; Bárdos, A.; Lábár, J.; Lendvai, J.; Varga, L. K.

    2004-02-01

    The effect of P addition on the thermal stability and on the bulk glass forming ability (BGFA) of cast iron based CiPxB4.35 (x = 4.35, 8.65, 10 at%) amorphous alloys was investigated by calorimetric (DSC and DTA) measurements. The amorphous alloys were prepared by melt spinning and by centrifugal copper mold casting. The crystallization kinetics was studied by DSC in the mode of continuos times linear heating and it was found that, both the glass transition temperature, Tg and the crystallization peak temperature, Tp are shifted to higher temperatures with increasing heating rate. The partial replacement of Ci by P atoms increases the thermal stability of the amorphous state and the BGFA. Bulk amorphous rods with diameters of 1, 1.5, 2, 2.5, and 3 mm as well as sheets with 1 × 4 mm2 cross-section were prepared by centrifugal copper mold casting and the amorphicity of the melt-spun ribbons and of the mold cast rods was investigated by XRD, and HRTEM.

  2. Feature-based imaging for cast stainless steel components: 1987 and 1988 field examinations: Final report

    SciTech Connect

    Shanker, R.; Jeong, P.; Williams, R.

    1989-01-01

    Digital-based inspection systems were used for the ultrasonic examinations and analysis of the hot-leg elbow in the Trojan Nuclear Power Plant in 1987 and 1988. This was the first time advanced systems were utilized during successive plant outages to monitor inspection data. The hot-leg elbow is made of statically cast stainless steel known for its mechanical strength and corrosion resistance. However, it presents unique difficulties in ultrasonic inspection because the large grain sizes can cause severe signal attenuation and beam redirection. The 1987 examination was authorized by Portland General Electric of Portland, Oregon, based on a study in 1985 which revealed that the hot-leg elbow could have experienced maximum strain and loading conditions because of steam generator snubber lockup. Seven indications were discovered during this examination; none of them was larger than the expected grain size in this material. The data were digitally processed at the EPRI NDE Center utilizing a personal computer based system that was integrated to other commercial systems and capable of feature-based imaging. Bandpass filtering and spatial averaging were found to increase signal-to-noise-ratio by as much as a factor of 2, i.e., 6 decibels. The hot-leg elbow was reexamined in 1988 using similar apparatus and inspection procedures. In addition to the seven 1987 indications, three more indications were discovered. These were determined to be in the midwall region. The largest of all the indications as reported by the inspection vendor was comparable to the average grain size, approximately 0.50 inch. The data were digitally processed at the EPRI NDE Center using similar techniques. Feature-based imaging of 1987 and 1988 inspection data made it possible to evaluate elbow conditions more reliably. 15 refs., 52 figs., 2 tabs.

  3. L(9) orthogonal design assisted formulation and evaluation of chitosan-based buccoadhesive films of miconazole nitrate.

    PubMed

    Tiwari, S; Singh, S; Rawat, M; Tilak, R; Mishra, B

    2009-07-01

    The present study was aimed to prepare and evaluate buccoadhesive films of miconazole nitrate (MCZ). The films based on chitosan were prepared by solvent casting method using L(9) orthogonal array design to release the drug above its minimum inhibitory concentration (MIC) for a prolonged period of time so as to reduce its frequency of administration. As per the experimental design, guar gum, HPMC K15M and HEC were added at three different levels to control the drug release. Films showed smooth, uniform and non-sticky surface with good flexibility and folding endurance. Thickness and weight-variation data showed no significant difference among the batches, indicating that the polymeric blend possessed a good film forming ability and its desired properties could easily be achieved by varying the composition of the casting solution. Films composed of chitosan with guar gum appeared to be tougher; comparatively more bioadhesive in vitro, resided to an appropriate time interval and swelled at a more reasonable rate than those containing HPMC and HEC, suggesting the superiority of guar gum over other polymers. In vitro drug release studies conducted on all batches and microbiological studies done on the statistically optimized formulation demonstrated that the films had ability to sustain the drug concentration above its MIC for 6 hrs, despite the incorporation of a smaller dose (2.5 mg/cm(2) of the film). Films, except CF2 and CF3, followed Fickian diffusion of release mechanism. FT-IR spectra revealed no interactions between the drug and polymers. PMID:19604145

  4. A PC based thin film dosimeter system

    NASA Astrophysics Data System (ADS)

    Miller, Arne; Hargittai, Peter; Kovacs, Andras

    2000-03-01

    A dosimeter system based on the Risø B3 dosimeter film, an office scanner for use with PC and the associated software is presented. The scanned image is analyzed either with standard software (Paint Shop Pro 5 or Excel) functions or with the computer code "Scanalizer" that allows presentation of two-dimensional dose maps. Stability and traceability of the dosimeter system is ensured through simultaneous measurement of reference dosimeters. In the dose range from 10 to 70 kGy reproducibility is approximately ±2% at 1 ?.

  5. In vitro corrosion of dental Au-based casting alloys in polyvinylpyrrolidone-iodine solution.

    PubMed

    Takasusuki, Norio; Ida, Yusuke; Hirose, Yukito; Ochi, Morio; Endo, Kazuhiko

    2013-01-01

    The corrosion and tarnish behaviors of two Au-based casting alloys (ISO type 1 and type 4 Au alloys) and their constituent pure metals, Au, Ag, Cu, Pt, and Pd in a polyvinylpyrrolidone-iodine solution were examined. The two Au alloys actively corroded, and the main anodic reaction for both was dissolution of Au as AuI?(-). The amount of Au released from the ISO type 1 Au alloy was significantly larger than that from the ISO type 4 Au alloy (P<0.05). Visible light spectrophotometry revealed that the type 1 alloy exhibited higher susceptibility to tarnishing than the type 4 alloy. The corrosion forms of the two Au alloys were found to be completely different, i.e., the type 1 alloy exhibited the corrosion attack over the entire exposed surface with a little irregularity whereas the type 4 alloy exhibited typical intergranular corrosion, which was caused by local cells produced by segregation of Pd and Pt. PMID:23718998

  6. Effects of Block Length and Solution-Casting Conditions on the Final Morphology and Properties of Disulfonated Poly(arylene ether sulfone) Multiblock Copolymer Films for Proton Exchange Membranes

    SciTech Connect

    Lee, M.; Park, J; Lee, H; Lane, O; Moore, R; McGrath, J; Baird, D

    2009-01-01

    The effects of block length and solution-casting conditions on the final microstructures and properties of disulfonated poly(arylene ether sulfone) multiblock copolymer (BPSH100-BPS0) films for proton exchange membranes were investigated based on the basic principles of microstructure formation of block copolymers. Morphological studies using transmission electron microscopy and small angle X-ray scattering demonstrated that as the block length increased, the inter-ionic-domain distance increased, with a subsequent increase in lamellar ordering and long-range continuity. Further enhancement in morphological order was achieved by simply utilizing a selective solvent, dimethylacetamide, which is good and marginal for the sulfonated and unsulfonated blocks, respectively, rather than a neutral solvent, N-metyl-2-pyrrolidone. These morphological enhancements led to higher proton conductivity and water uptake. Drying temperature and/or solvent removal rate were observed to have considerable effects on water uptake and swelling behavior, being coupled with solvent selectivity. Also, the multiblock copolymer consisting of longer blocks was found to be more sensitive to the variation of the processing conditions such as solvent type and film drying temperature.

  7. Creep crack growth behavior at 1033 K of directionally solidified CM 247 LC -- A cast nickel-base superalloy

    SciTech Connect

    Gopala Krishna, M.S.; Sriramamurthy, A.M. [Defence Metallurgical Research Lab., Hyderabad (India)] [Defence Metallurgical Research Lab., Hyderabad (India); Radhakrishnan, V.M. [I.I.T., Madras (India). Dept. of Metallurgical Engineering] [I.I.T., Madras (India). Dept. of Metallurgical Engineering

    1996-12-01

    Creep crack growth (CCG) studies on metals and alloys have gained importance and momentum in the recent years. In the present study, the creep crack growth behavior of a directionally solidified (DS) cast nickel-base superalloy has been investigated at 1,033K and the results obtained are reported here. The alloy studied is commonly used for producing turbine blades and vanes for aeroengine applications.

  8. Surface abuse when machining cast iron (G-17) and nickel-base superalloy (Inconel 718) with ceramic tools

    Microsoft Academic Search

    E. O. Ezugwu; S. H. Tang

    1995-01-01

    Single-point continuous-turning tests were carried out on a G-17 cast iron and a nickel base, Inconel 718, alloy using round and rhomboid-shape pure oxide (Al2O3 + ZrO2) and mixed oxide (Al2O3 + TiC) ceramic tools to study the extent of damage on the machined surfaces under optimum cutting conditions. The test results show that improved surface finish and lesser damage

  9. Hydroxyapatite scaffolds processed using a TBA-based freeze-gel casting/polymer sponge technique.

    PubMed

    Yang, Tae Young; Lee, Jung Min; Yoon, Seog Young; Park, Hong Chae

    2010-05-01

    A novel freeze-gel casting/polymer sponge technique has been introduced to fabricate porous hydroxyapatite scaffolds with controlled "designer" pore structures and improved compressive strength for bone tissue engineering applications. Tertiary-butyl alcohol (TBA) was used as a solvent in this work. The merits of each production process, freeze casting, gel casting, and polymer sponge route were characterized by the sintered microstructure and mechanical strength. A reticulated structure with large pore size of 180-360 microm, which formed on burn-out of polyurethane foam, consisted of the strut with highly interconnected, unidirectional, long pore channels (approximately 4.5 microm in dia.) by evaporation of frozen TBA produced in freeze casting together with the dense inner walls with a few, isolated fine pores (<2 microm) by gel casting. The sintered porosity and pore size generally behaved in an opposite manner to the solid loading, i.e., a high solid loading gave low porosity and small pore size, and a thickening of the strut cross section, thus leading to higher compressive strengths. PMID:20099009

  10. Measurement of concrete E-modulus evolution since casting: A novel method based on ambient vibration

    SciTech Connect

    Azenha, Miguel, E-mail: miguel.azenha@civil.uminho.p [LABEST - Laboratory for the Concrete Technology and Structural Behaviour, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); ISISE - Institute for Sustainability and Innovation in Structural Engineering, Universidade do Minho, Escola de Engenharia, Campus de Azurem, 4800-058 Guimaraes (Portugal); Magalhaes, Filipe [VIBEST - Laboratory of Vibrations and Structural Monitoring, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Faria, Rui [LABEST - Laboratory for the Concrete Technology and Structural Behaviour, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal); Cunha, Alvaro [VIBEST - Laboratory of Vibrations and Structural Monitoring, Faculdade de Engenharia da Universidade do Porto, Rua Dr. Roberto Frias, 4200-465 Porto (Portugal)

    2010-07-15

    The use of ambient vibration tests to characterize the evolution of E-modulus of concrete right after casting is investigated in this paper. A new methodology is proposed, which starts by casting a concrete cylindrical beam inside a hollow acrylic formwork. This beam is then placed horizontally, simply supported at both extremities, and vertical accelerations resulting from ambient vibration are measured at mid-span. Processing these mid-span acceleration time series using power spectral density functions allows a continuous identification of the first flexural frequency of vibration of the composite beam, which in turn is correlated with the evolutive E-modulus of concrete since casting. Together with experiments conducted with the proposed methodology, a complementary validation campaign for concrete E-modulus determination was undertaken by static loading tests performed on the composite beam, as well as by standard compressive tests of concrete cylinders of the same batch loaded at different ages.

  11. In-situ observations of oxidation and phase stability in cast nickel-based intermetallic alloys

    SciTech Connect

    Babu, Suresh S. [Edison Welding Institute; Specht, Eliot D [ORNL; Santella, Michael L [ORNL; Ice, Gene E [ORNL; David, Stan A [ORNL

    2006-01-01

    The effects of the as-cast microstructure on the oxidation characteristics of two Ni-Al-Cr alloys with either gamma or gamma' primary solidification were investigated with an in-situ, time-resolved X-ray diffraction (TRXRD) technique using synchrotron radiation. The measurements, carried out during rapid heating and cooling, showed that a segregated microstructure in these cast alloys leads to the preferential formation of zirconium oxide before the formation of aluminum oxides is detected. The oxidation leads to a change in the phase stability and to the modification of surface microstructures. Computational thermodynamic models were used to explain the preferential formation of oxides in the as-cast microstructure.

  12. Synthesis of FeS2 Nano Crystals for ink based thin film solar cells

    NASA Astrophysics Data System (ADS)

    Dhakal, Tara; Ganta, Lakshmi; Westgate, Charles

    2012-02-01

    With a band gap of 0.95 eV and high absorption coefficient (?10^5 cm-1), FeS2 is ideal for use as a p-type hetero-junction partner in a solar cell. Although pyrite is abundant in nature, getting the right phase for thin films is difficult due to the various phases of iron sulfides. We propose an ink based process for attaining the pyrite phase. Our experimental process involves use of low cost non-toxic chemicals for synthesis. The process involves reacting iron (II) chloride, 1, 2-hexadecanediol with 70% Oleylamine at 100 C for 1 hour followed by introduction of sulfur and reacting for 2 hours at 220 C. The reaction provides perfect nano crystals dispersed in a carbon based solution which is later subjected to centrifugation to separate the crystals. After multiple cleaning cycles, the crystals were dispersed in chloroform for uniform suspension. SEM image the film formed by drop casting followed by argon-annealing revealed that the nano-crystals were hexagonal with sizes ranging from 100-500nm with perfect symmetry. EDAX analysis showed the iron to sulfur atomic percentage ratio 1:1. The argon annealed film was then sulfurized using an organic sulfur source at 400 C, which gave a desired pyrite cubic phase. We will present the growth process and the efficiency data for this ink based FeS2 solar cell.

  13. CIGS-based solar cells prepared from electrodeposited precursor films

    Microsoft Academic Search

    Raghu N. Bhattacharya; Mi-Kyung Oh; Youngho Kim

    Previously, we reported 15.4%-efficient [1] copper indium gallium diselenide (CIGS)-based photovoltaic devices from electrodeposited precursor films in which the final film composition was adjusted using the physical vapor deposition (PVD) method. At present, we are fabricating CIGS-based solar cells directly from electrodeposited precursor films, eliminating the expensive PVD step. Electrodeposited CIGS absorber layers are fabricated by a three-stage electrodeposition process

  14. Electrochemistry and current control in surface films based on silica-azure redox nanoparticles, carbon nanotubes, enzymes, and polyelectrolytes.

    PubMed

    Karra, Sushma; Zhang, Maogen; Gorski, Waldemar

    2013-01-15

    The redox active nanoparticles were developed by covalently attaching redox dye Azure C (AZU) to commercial silica nanoparticles (SN) via the silylated amine and glutaric dialdehyde links. The SN-AZU nanoparticles were studied as redox mediators for the oxidation of reduced ?-nicotinamide adenine dinucleotide (NADH) in two polymeric films. The first film (F1) was composed of SN-AZU, carbon nanotubes, and cationic polyelectrolyte chitosan. The second film (F2) contained also added enzyme glucose dehydrogenase and its cofactor ?-nicotinamide adenine dinucleotide (NAD(+)). The films F1 and F2 were cast on the glassy carbon electrodes, covered with an anionic polyelectrolyte Nafion, and their electrochemical properties were probed with NADH and glucose, respectively, using voltammetry, amperometry, and potentiometry. The Nafion overcoat reduced the sensitivity of F1/Nafion film electrodes to NADH by >98%. In contrast, depending on the concentration of Nafion, the sensitivity of the F2/Nafion film electrodes (reagentless biosensors) to glucose increased by up to 340%. The amplification of glucose signal was ascribed to the Donnan exclusion and ensuing Nafion-gated ionic fluxes, which enhanced enzyme activity in films F2. The proposed model predicts that such signal amplification should be also feasible in the case of other enzyme-based biosensors. PMID:23244040

  15. Microstructure Based Modeling of ? Phase Influence on Mechanical Response of Cast AM Series Mg Alloys

    SciTech Connect

    Barker, Erin I.; Choi, Kyoo Sil; Sun, Xin; Deda, Erin; Allison, John; Li, Mei; Forsmark, Joy; Zindel, Jacob; Godlewski, Larry

    2014-09-30

    Magnesium alloys have become popular alternatives to aluminums and steels for the purpose of vehicle light-weighting. However, Mg alloys are hindered from wider application due to limited ductility as well as poor creep and corrosion performance. Understanding the impact of microstructural features on bulk response is key to improving Mg alloys for more widespread use and for moving towards truly predicting modeling capabilities. This study focuses on modeling the intrinsic features, particularly volume fraction and morphology of beta phase present, of cast Mg alloy microstructure and quantifying their impact on bulk performance. Computational results are compared to experimental measurements of cast plates of Mg alloy with varying aluminum content.

  16. Polyvinyl acetate-based film coatings.

    PubMed

    Kolter, K; Dashevsky, A; Irfan, Muhamad; Bodmeier, R

    2013-12-01

    Polyvinyl acetate-based colloidal aqueous polymer dispersion Kollicoat(®) SR 30 D results in coatings characterized by moderate swelling behaviour, lipophilicity, pH-independent permeability for actives and high flexibility to withstand mechanical stress and is therefore used for controlled release coating. The colloidal aqueous polymer dispersion of Kollicoat(®) SR 30 D can be easily processed due to an optimal low minimum film forming temperature (MFT) of 18 °C without plasticizer addition and a thermal after-treatment (curing) of coated pellets. The drug release from Kollicoat(®) SR 30 D coated pellets was almost pH independent. Drug release could be easily adjusted by coating level or addition of soluble pore forming polymers. Physically stable Kollicoat(®) SR 30 D dispersions were obtained with the water-soluble polymers Kollidon(®) 30 and Kollicoat(®) IR up to 50% w/w. The addition of only 10% w/w triethyl citrate as plasticizer improved the flexibility of the films significantly and allowed compaction of the pellets. The drug release was almost independent of the compression force and the pellet content of the tablets. The inclusion of various tableting excipients slightly affected the drug release, primarily because of a different disintegration rate of the tablets. A combination of Kollicoat(®) SR 30 D and Kollicoat(®) IR with higher coating levels>10 mg/cm(2) is a relatively new alternative to OROS system which does not require drilling. PMID:24076229

  17. Clean Metal Casting

    SciTech Connect

    Makhlouf M. Makhlouf; Diran Apelian

    2002-02-05

    The objective of this project is to develop a technology for clean metal processing that is capable of consistently providing a metal cleanliness level that is fit for a given application. The program has five tasks: Development of melt cleanliness assessment technology, development of melt contamination avoidance technology, development of high temperature phase separation technology, establishment of a correlation between the level of melt cleanliness and as cast mechanical properties, and transfer of technology to the industrial sector. Within the context of the first task, WPI has developed a standardized Reduced Pressure Test that has been endorsed by AFS as a recommended practice. In addition, within the context of task1, WPI has developed a melt cleanliness sensor based on the principles of electromagnetic separation. An industrial partner is commercializing the sensor. Within the context of the second task, WPI has developed environmentally friendly fluxes that do not contain fluorine. Within the context of the third task, WPI modeled the process of rotary degassing and verified the model predictions with experimental data. This model may be used to optimize the performance of industrial rotary degassers. Within the context of the fourth task, WPI has correlated the level of melt cleanliness at various foundries, including a sand casting foundry, a permanent mold casting foundry, and a die casting foundry, to the casting process and the resultant mechanical properties. This is useful in tailoring the melt cleansing operations at foundries to the particular casting process and the desired properties of cast components.

  18. Electron Beam Welding Characteristics of Cast Iron and Bonding of Mild Steel to Cast Iron by using Iron-base Alloy of High Nickel Content

    NASA Astrophysics Data System (ADS)

    Hatate, Minoru; Shiota, Toshio; Nagasaki, Yoichi; Abe, Nobuyuki; Amano, Masaharu; Tanaka, Toshio

    Bonding characteristics of mild steel to cast iron using electron beam welding (EBW) process are investigated from the viewpoint of microstructure and mechanical properties. When the electron beam is radiated to a cast iron, remelting of the surface and corresponding rapid cooling take place, and it results in formation of brittle fine-cementite structure whose hardness is over 700 Hv. As Ni is an alloying element that may prevent formation of cementite, we compare two kinds of welding methods with Ni addition. One method is EBW process, radiating the electron beam to a thin plate made of spheroidal graphite cast iron with a high Ni content after the plate inserts between cast iron and steel, and other one is a metal active gas (MAG) welding process using a Fe-Ni wire. Bonding tensile strength by EBW process is higher than that by MAG welding process. In case of welding of cast iron and other metallic material, EBW process is found to be more advantageous than MAG welding process.

  19. Optimization of excess Bi doping to enhance ferroic orders of spin casted BiFeO3 thin film

    NASA Astrophysics Data System (ADS)

    Gupta, Surbhi; Tomar, Monika; Gupta, Vinay; James, A. R.; Pal, Madhuparna; Guo, Ruyan; Bhalla, Amar

    2014-06-01

    Multiferroic Bismuth Ferrite (BiFeO3) thin films with varying excess bismuth (Bi) concentration were grown by chemical solution deposition technique. Room temperature multiferroic properties (ferromagnetism, ferroelectricity, and piezoelectricity) of the deposited BiFeO3 thin films have been studied. High resolution X-ray diffraction and Raman spectroscopy studies reveal that the dominant phases formed in the prepared samples change continuously from a mixture of BiFeO3 and Fe2O3 to pure BiFeO3 phase and, subsequently, to a mixture of BiFeO3 and Bi2O3 with increase in the concentration of excess Bi from 0% to 15%. BiFeO3 thin films having low content (0% and 2%) of excess Bi showed the traces of ferromagnetic phase (?-Fe2O3). Deterioration in ferroic properties of BiFeO3 thin films is also observed when prepared with higher content (15%) of excess Bi. Single-phased BiFeO3 thin film prepared with 5% excess Bi concentration exhibited the soft ferromagnetic hysteresis loops and ferroelectric characteristics with remnant polarization 4.2 ?C/cm2 and saturation magnetization 11.66 emu/g. The switching of fine spontaneous domains with applied dc bias has been observed using piezoresponse force microscopy in BiFeO3 thin films having 5% excess Bi. The results are important to identify optimum excess Bi concentration needed for the formation of single phase BiFeO3 thin films exhibiting the improved multiferroic properties.

  20. Study on aluminium-based single films.

    PubMed

    Vinod Kumar, G S; García-Moreno, F; Babcsán, N; Brothers, A H; Murty, B S; Banhart, J

    2007-12-28

    In the present paper the authors studied isolated metallic films made from the same material used for making metallic foams, and then characterised their properties. Metal films were made from a liquid aluminium alloy reinforced with ceramic particles of known concentration. Melts without such particles were also investigated. It is shown that stable films could not be made from Al-Si alloy having no particles, and just extremely thin and fragile films could be made from commercially-pure Al. In contrast, aluminium alloys containing particles such as SiC and TiB(2) allowed pulling thin, stable films, which did not rupture. Significant thinning of films was observed when the particle concentration in the melt decreased. By in situ X-ray monitoring of liquid films during pulling, film thickness and drainage effects within the liquid film could be studied. The morphology and microstructure of films was characterised after solidification. Our work shows that the question of how foams are stabilised can be studied using a simplified system such as a film, instead of having to deal with the multitude of different structural elements present in a foam. PMID:18060172

  1. Assessing the Robustness of Chemical Prioritizations Based on ToxCast Chemical Profiling

    EPA Science Inventory

    A central goal of the U.S. EPA?s ToxCast? program is to provide empirical, scientific evidence to aid in prioritizing the toxicity testing of thousands of chemicals. The agency has developed a prioritization approach, the Toxicological Prioritization Index (ToxPi?), that calculat...

  2. High-Throughput Models for Exposure-Based Chemical Prioritization in the ExpoCast Project

    EPA Science Inventory

    The United States Environmental Protection Agency (U.S. EPA) must characterize potential risks to human health and the environment associated with manufacture and use of thousands of chemicals. High-throughput screening (HTS) for biological activity allows the ToxCast research pr...

  3. Fabrication of x-ray absorption gratings via micro-casting for grating-based phase contrast imaging

    NASA Astrophysics Data System (ADS)

    Lei, Yaohu; Du, Yang; Li, Ji; Zhao, Zhigang; Liu, Xin; Guo, Jinchuan; Niu, Hanben

    2014-01-01

    Grating-based x-ray differential phase contrast (DPC) imaging has shown huge potential. For broad applications, it is essential that the key components are low-cost, especially the absorption gratings. We therefore proposed and developed a micro-casting process for fabricating x-ray absorption gratings with bismuth. This process is feasible for mass production at low cost, with a large format, and a high aspect ratio. To develop this kind of absorption grating, an array with deep trenches was fabricated by photo-assisted electrochemical etching in a silicon wafer. The trenches were then filled with bubble-free, molten bismuth via capillary action and surface tension. Bismuth was attractive as a filling material because of its great mass absorption coefficient, low cost and broad environmental compatibility. Furthermore, our micro-casting process provided bismuth absorption gratings with a clean surface and no need for post treatment. To test their performance in x-ray DPC imaging, two bismuth absorption gratings, one as a periodic source and another as the analyzer, were used with periods of 42 and 3 µm and depths of 110 and 150 µm, respectively. The acquired phase-contrast images demonstrated that the micro-casting process produces qualified gratings for x-ray DPC imaging.

  4. INFLUENCE OF FILM STRUCTURE AND LIGHT ON CHARGE TRAPPING AND DISSIPATION DYNAMICS IN SPUN-CAST ORGANIC THIN-FILM TRANSISTORS MEASURED BY SCANNING KELVIN PROBE MICROSCOPY

    SciTech Connect

    Teague, L.; Moth, M.; Anthony, J.

    2012-05-03

    Herein, time-dependent scanning Kelvin probe microscopy of solution processed organic thin film transistors (OTFTs) reveals a correlation between film microstructure and OTFT device performance with the location of trapped charge within the device channel. The accumulation of the observed trapped charge is concurrent with the decrease in I{sub SD} during operation (V{sub G}=-40 V, V{sub SD}= -10 V). We discuss the charge trapping and dissipation dynamics as they relate to the film structure and show that application of light quickly dissipates the observed trapped charge.

  5. Interferometric measurement method of thin film thickness based on FFT

    NASA Astrophysics Data System (ADS)

    Shuai, Gaolong; Su, Junhong; Yang, Lihong; Xu, Junqi

    2009-05-01

    The kernel of modern interferometry is to obtain necessary surface shape and parameter by processing interferogram with reasonable algorithm. The paper studies the basic principle of interferometry involving 2-D FFT, proposes a new method for measuring thin film thickness based on FFT: by CCD receiving and acquired card collecting with the help of Twyman-Green interferometer, can a fringe interferogram of the measured thin film be obtained. Based on the interferogram processing knowledge, an algorithm processing software/program can be prepared to realize identification of the edge films, regional extension, filtering, unwrapping the wrapped phase etc. And in this way can the distribution of film information-coated surface be obtained and the thickness of thin film samples automatically measured. The findings indicate the PV value and RMS value of the measured film samples are 0.256 ? and 0.068 ? respectively and prove the new method has high precision.

  6. Integrated thick-film nanostructures based on spinel ceramics.

    PubMed

    Klym, Halyna; Hadzaman, Ivan; Shpotyuk, Oleh; Brunner, Michael

    2014-01-01

    Integrated temperature-humidity-sensitive thick-film structures based on spinel-type semiconducting ceramics of different chemical compositions and magnesium aluminate ceramics were prepared and studied. It is shown that temperature-sensitive thick-film structures possess good electrophysical characteristics in the region from 298 to 358 K. The change of electrical resistance in integrated thick-film structures is 1 order, but these elements are stable in time and can be successfully used for sensor applications. PMID:24670141

  7. Integrated thick-film nanostructures based on spinel ceramics

    PubMed Central

    2014-01-01

    Integrated temperature-humidity-sensitive thick-film structures based on spinel-type semiconducting ceramics of different chemical compositions and magnesium aluminate ceramics were prepared and studied. It is shown that temperature-sensitive thick-film structures possess good electrophysical characteristics in the region from 298 to 358 K. The change of electrical resistance in integrated thick-film structures is 1 order, but these elements are stable in time and can be successfully used for sensor applications. PMID:24670141

  8. AsCast Acicular Ductile Aluminum Cast Iron

    Microsoft Academic Search

    SM Mostafavi Kashani; SMA Boutorabi

    2009-01-01

    The effects of nickel (2.2%) and molybdenum (0.6%) additions on the kinetics, microstructure, and mechanical properties of ductile aluminum cast iron were studied under the as-cast and tempered conditions. Test bars machined from cast to size samples were used for mechanical and metallurgical studies. The results showed that adding nickel and molybdenum to the base iron produced an upper bainitic

  9. Development of a novel antimicrobial film based on chitosan with LAE (ethyl-N(?)-dodecanoyl-l-arginate) and its application to fresh chicken.

    PubMed

    Higueras, Laura; López-Carballo, Gracia; Hernández-Muñoz, Pilar; Gavara, Rafael; Rollini, Manuela

    2013-08-01

    Chitosan (CS) films incorporating the antimicrobial compound ethyl-N(?)-dodecanoyl-l-arginate (LAE) were developed for food packaging applications. Cast chitosan films were made with 1, 5 or 10% LAE and 20% glycerol in the film forming solution. Optical properties, release of LAE and antimicrobial activity of developed films was determined. The minimum inhibitory concentration (MIC) and the minimum biocide concentration (MBC) of LAE were determined. CS films with LAE were transparent and uniform, without discontinuities or visible particles and no visual differences could be perceived between CS and CS-LAE films. When in contact with an aqueous food simulant, the agent was fully released following a Fickian behavior in a few hours at 4 and 28°C. Antimicrobial activity of films against mesophiles, psychrophiles, Pseudomonas spp., colifoms, lactic acid bacteria, hydrogen sulfide-producing bacteria, yeast and fungi, was evaluated at two, six and eight days for its application on chicken breast fillets. Films were active against bacteria, yeasts and fungi in liquid and solid media. CS films evidenced antimicrobial activity in the range 0.47-2.96 log reductions, while CS-5%LAE film produced 1.78-5.81 log reduction. Results highlighted that LAE incorporation in a chitosan-based packaging structure may provide a relevant antimicrobial activity that could improve the stability of fresh poultry products. PMID:23816804

  10. Hair casts.

    PubMed

    Parmar, Sweta S; Parmar, Kirti S; Shah, Bela J

    2014-10-01

    Hair casts or pseudonits are circumferential concretions, which cover the hair shaft in such a way that, it could be easily removed. They are thin, cylindrical, and elongated in length. We present an unusual case of an 8-year-old girl presenting with hair casts. Occurrence of these is unusual, and they may have varied associations. This patient was suffering from developmental delay. It is commonly misdiagnosed as and very important to differentiate from pediculosis capitis. PMID:25396168

  11. Hair casts

    PubMed Central

    Parmar, Sweta S.; Parmar, Kirti S.; Shah, Bela J.

    2014-01-01

    Hair casts or pseudonits are circumferential concretions, which cover the hair shaft in such a way that, it could be easily removed. They are thin, cylindrical, and elongated in length. We present an unusual case of an 8-year-old girl presenting with hair casts. Occurrence of these is unusual, and they may have varied associations. This patient was suffering from developmental delay. It is commonly misdiagnosed as and very important to differentiate from pediculosis capitis. PMID:25396168

  12. Creep deformation mechanisms in high-pressure die-cast magnesium-aluminum-base alloys

    Microsoft Academic Search

    W. Blum; Y. J. Li; X. H. Zeng; P. Zhang; B. von Großmann; C. Haberling

    2005-01-01

    Creep of die-cast Mg alloys is described as an integral part of their plastic deformation behavior in terms of stress-strain-rate-strain\\u000a relations. Creep tests yield information on yield stress, work hardening, maximum deformation resistance (minimum creep rate),\\u000a and work softening. Testing in compression avoids influences by fracture. Data on the alloy AJ52 (5Al, 2Sr) in the temperature\\u000a range between 135 °C

  13. AC conductivity and electrochemical studies of PVA/PEG based polymer blend electrolyte films

    NASA Astrophysics Data System (ADS)

    Polu, Anji Reddy; Kumar, Ranveer; Dehariya, Harsha

    2012-06-01

    Polymer blend electrolyte films based on Polyvinyl alcohol(PVA)/Poly(ethylene glycol)(PEG) and magnesium nitrate (Mg(NO3)2) were prepared by solution casting technique. Conductivity in the temperature range 303-373 K and transference number measurements have been employed to investigate the charge transport in this polymer blend electrolyte system. The highest conductivity is found to be 9.63 × 10-5 S/cm at 30°C for sample with 30 weight percent of Mg(NO3)2 in PVA/PEG blend matrix. Transport number data shows that the charge transport in this polymer electrolyte system is predominantly due to ions. Using this electrolyte, an electrochemical cell with configuration Mg/(PVA+PEG+Mg(NO3)2)/(I2+C+electrolyte) was fabricated and its discharge characteristics profile has been studied.

  14. Resistivity-Based Evaluation of the Fatigue Behavior of Cast Irons

    NASA Astrophysics Data System (ADS)

    Germann, Holger; Starke, Peter; Eifler, Dietmar

    2012-08-01

    Cast irons are used in particular for highly stressed components in the automotive and commercial vehicle industry, e.g., for crankcases and in the wind power industry, e.g., for rotor hubs. The mechanical properties of cast irons are strongly influenced by parameters like phase composition of the matrix, graphite shape, micro-pinholes, and micro-cracks. The measurement of the electrical resistance in the unloaded state and its change during cyclic loading offers the possibility to get detailed information about the actual defect density and the cyclic deformation behavior. In the scope of the present work, stress-controlled load increase tests and constant amplitude tests were carried out at ambient temperature with specimens of the perlitic cast irons EN-GJL-250 (ASTM A48 35B), EN-GJV-400, and EN-GJS-600 (ASTM 80-55-06). Beside electrical measurements, scanning electron microscopy (SEM) was used to characterize the microstructure and to correlate the change of microstructural details with cyclic properties.

  15. Pigmented casts.

    PubMed

    Miteva, Mariya; Romanelli, Paolo; Tosti, Antonella

    2014-01-01

    Pigmented casts have been reported with variable frequency in scalp biopsies from alopecia areata, trichotillomania, chemotherapy-induced alopecia and postoperative (pressure induced) alopecia. Their presence and morphology in other scalp disorders has not been described. The authors assessed for the presence and morphology of pigmented casts in 308 transversely bisected scalp biopsies from nonscarring and scarring alopecia, referred to the Department of Dermatology, University of Miami within a year. The pigmented casts were present in 21 of 29 cases of alopecia areata (72%), 7 of 7 cases of trichotillomania (100%), 1 case of friction alopecia, 4 of 28 cases of central centrifugal cicatricial alopecia (14%), and 4 of 4 cases of dissecting cellulitis (100%). They did not show any distinguishing features except for the morphology in trichotillomania, which included twisted, linear (zip), and "button"-like pigment aggregation. The linear arrangement was found also in friction alopecia and dissecting cellulitis. Pigmented casts in the hair canals of miniaturized/vellus hairs was a clue to alopecia areata. Pigmented casts can be observed in biopsies of different hair disorders, but they are not specific for the diagnosis. Horizontal sections allow to better assess their morphology and the follicular level of presence of pigmented casts, which in the context of the other follicular findings may be a clue to the diagnosis. PMID:23823025

  16. Electrocaloric devices based on thini-film heat switches

    SciTech Connect

    Epstein, Richard I [Los Alamos National Laboratory; Malloy, Kevin J [UNM

    2009-01-01

    We describe a new approach to refrigeration and electrical generation that exploits the attractive properties of thin films of electrocaloric materials. Layers of electrocaloric material coupled with thin-film heat switches can work as either refrigerators or electrical generators, depending on the phasing of the applied voltages and heat switching. With heat switches based on thin layers of liquid crystals, the efficiency of these thin-film heat engines can be at least as high as that of current thermoelectric devices. Advanced heat switches would enable thin-film heat engines to outperform conventional vaporcompression devices.

  17. Transparent superhydrophobic films based on silica nanoparticles.

    PubMed

    Bravo, Javier; Zhai, Lei; Wu, Zhizhong; Cohen, Robert E; Rubner, Michael F

    2007-06-19

    We demonstrate a layer-by-layer processing scheme that can be utilized to create transparent superhydrophobic films from SiO2 nanoparticles of various sizes. By controlling the placement and level of aggregation of differently sized nanoparticles within the resultant multilayer thin film, it is possible to optimize the level of surface roughness to achieve superhydrophobic behavior with limited light scattering. Transparent superhydrophobic films were created by the sequential adsorption of silica nanoparticles and poly(allylamine hydrochloride). The final assembly was rendered superhydrophobic with silane treatment. Optical transmission levels above 90% throughout most of the visible region of the spectrum were realized in optimized coatings. Advancing water droplet contact angles as high as 160 degrees with low contact angle hysteresis (<10 degrees ) were obtained for the optimized multilayer thin films. Because of the low refractive index of the resultant porous multilayer films, they also exhibited antireflection properties. PMID:17523683

  18. Optimal grid-based methods for thin film micromagnetics simulations

    E-print Network

    Muratov, Cyrill

    ­3]. Of particular interest are these structures in thin magnetic metal films [4­8] which have been intensely play an important role in multilayer magnetic-normal metal struc- tures for current-induced reversalOptimal grid-based methods for thin film micromagnetics simulations C.B. Muratov a,*, V.V. Osipov b

  19. Wettability and protein adsorption on HTPB-based polyurethane films

    Microsoft Academic Search

    Jen Ming Yang; Hao Tzu Lin

    2001-01-01

    Hydroxyl-terminated polybutadiene-based (HTPB) polyurethane (PU) with different molar ratios of dimethyol propionic acid and 1,4-butane diol as the chain extender was synthesized by solution polymerization. The present PU was then cast into a membrane and subsequently characterized by the Fourier transform infrared spectroscopy. It was found that the participation of carbonyl group in hydrogen bonding increased with the content of

  20. Carboxymethylcellulose–montmorillonite nanocomposite films activated with murta ( Ugni molinae Turcz) leaves extract

    Microsoft Academic Search

    Marcela Quilaqueo Gutiérrez; Ignacio Echeverría; Mónica Ihl; Valerio Bifani; Adriana N. Mauri

    The functionality of nanocomposite films based on carboxymethylcellulose (CMC) and montmorillonite (MMT) activated with murta (Ugni molinae Turcz) leaves extract was studied. Films were prepared by casting from film-forming dispersions containing CMC, glycerol (used as plasticizer) and different concentrations of MMT, using water or murta extract as solvent. The addition of MMT increased the tensile strength and the elasticity modulus

  1. Crystallization of zirconia based thin films.

    PubMed

    Stender, D; Frison, R; Conder, K; Rupp, J L M; Scherrer, B; Martynczuk, J M; Gauckler, L J; Schneider, C W; Lippert, T; Wokaun, A

    2015-07-01

    The crystallization kinetics of amorphous 3 and 8 mol% yttria stabilized zirconia (3YSZ and 8YSZ) thin films grown by pulsed laser deposition (PLD), spray pyrolysis and dc-magnetron sputtering are explored. The deposited films were heat treated up to 1000 °C ex situ and in situ in an X-ray diffractometer. A minimum temperature of 275 °C was determined at which as-deposited amorphous PLD grown 3YSZ films fully crystallize within five hours. Above 325 °C these films transform nearly instantaneously with a high degree of micro-strain when crystallized below 500 °C. In these films the t'' phase crystallizes which transforms at T > 600 °C to the t' phase upon relaxation of the micro-strain. Furthermore, the crystallization of 8YSZ thin films grown by PLD, spray pyrolysis and dc-sputtering are characterized by in situ XRD measurements. At a constant heating rate of 2.4 K min(-1) crystallization is accomplished after reaching 800 °C, while PLD grown thin films were completely crystallized already at ca. 300 °C. PMID:26119755

  2. Combination of bortezomib-based chemotherapy and extracorporeal free light chain removal for treating cast nephropathy in multiple myeloma

    Microsoft Academic Search

    Ulrike Bachmann; Ralf Schindler; Markus Storr; Andreas Kahl; Achim Joerres; Isrid Sturm

    2008-01-01

    Besides amyloidosis and light chain deposition disease, the most common histological type of renal lesion is cast nephropathy in 30% of patients with multiple myeloma (2). In contrast to amyloidosis, cast nephropathy is believed to be potentially reversible when circulating light chains are rapidly reduced. We report on three patients with multiple myeloma and cast nephropathy treated with a bortezomib-

  3. Automated flaw detection in aluminum castings based on the tracking of potential defects in a radioscopic image sequence

    Microsoft Academic Search

    Domingo Mery; Dieter Filbert

    2002-01-01

    Presents a method for inspecting aluminum castings automatically from a sequence of radioscopic images taken at different positions of the casting. The classic image-processing methods for flaw detection of aluminum castings use a bank of filters to generate an error-free reference image. This reference image is compared with the real radioscopic image, and flaws are detected at the pixels where

  4. Development of an antimicrobial material based on a nanocomposite cellulose acetate film for active food packaging.

    PubMed

    Rodríguez, Francisco J; Torres, Alejandra; Peñaloza, Ángela; Sepúlveda, Hugo; Galotto, María J; Guarda, Abel; Bruna, Julio

    2014-01-01

    Nanocomposites based on biopolymers have been recognised as potential materials for the development of new ecofriendly food packaging. In addition, if these materials incorporate active substances in their structure, the potential applications are much higher. Therefore, this work was oriented to develop nanocomposites with antimicrobial activity based on cellulose acetate (CA), a commercial organoclay Cloisite30B (C30B), thymol (T) as natural antimicrobial component and tri-ethyl citrate (TEC) as plasticiser. Nanocomposites were prepared by a solvent casting method and consisted of 5% (w/w) of C30B, 5% (w/w) of TEC and variable content of T (0%, 0.5% and 2% w/w). To evaluate the effect of C30B into the CA matrix, CA films without this organoclay but with T were also prepared. All nanocomposites showed the intercalation of CA into the organoclay structure; furthermore this intercalation was favoured when 2% (w/w) of T was added to the nanocomposite. In spite of the observed intercalation, the presence of C30B inside the CA matrices increased the opacity of the films significantly. On the other hand, T showed a plasticiser effect on the thermal properties of CA nanocomposites decreasing glass transition, melting temperature and melting enthalpy. The presence of T in CA nanocomposites also allowed the control de Listeria innocua growth when these materials were placed in contact with this Gram-positive bacterium. Interestingly, antimicrobial activity was increased with the presence of C30B. Finally, studies on T release showed that the clay structure inside the CA matrix did not affect its release rate; however, this nanofiller affected the partition coefficient KP/FS which was higher to CA nanocomposites films than in CA films without organoclay. The results obtained in the present study are really promising to be applied in the manufacture of food packaging materials. PMID:24345085

  5. Processing and characterization of extruded zein-based biodegradable films

    NASA Astrophysics Data System (ADS)

    Wang, Ying

    The objectives of this study were to prepare biodegradable zein films by extrusion processing and to evaluate relevant physical properties of resulting films with respect to their potential as packaging materials. The manufacture of protein-based packaging films by extrusion has remained a challenge. In this study, a zein resin was prepared by combining zein and oleic acid. This resin was formed into films by blown extrusion at the bench-top scale. Resin moisture content and extruder barrel temperature profile were identified as major parameters controlling the process. The optimum temperature of the blowing head was determined to be 40--45°C, while optimum moisture at film collection was 14--15%. Physico-chemical properties of the extruded products were characterized. Extruded products exhibited plastic behavior and ductility. Morphology characterization by SEM showed micro voids in extruded zein sheets, caused by entrapped air bubbles or water droplets. DSC characterization showed that zein was effectively plasticized by oleic acid as evidenced by the lowered glass transition temperature of zein films. X-ray scattering was used to investigate changes in zein molecular aggregation during processing. It was observed that higher mechanical energy treatment progressively disrupted zein molecular aggregates, resulting in a more uniform distribution of individual zein molecules. With the incorporation of oleic acid as plasticizer and monoglycerides as emulsifier, zein formed structures with long-range periodicity which varied depending on the formulation and processing methods. Processing methods for film formation affected the binding of oleic acid to zein with higher mechanical energy treatment resulting in better interaction between the two components. The moisture sorption capacity of extruded zein films was reduced due to the compact morphology caused by extrusion. Plasticization with oleic acid further reduced moisture sorption of zein films. The overall conclusion of this study is that blown film extrusion of zein-oleic acid resins is a promising process for the manufacture of zein films, resulting in films with potential for packaging applications.

  6. Effect of surfactants on the functional properties of gelatin–polysaccharide-based films

    Microsoft Academic Search

    Hulda Chambi; Carlos Grosso

    2011-01-01

    The aim of this study was to evaluate the effects of the addition of surfactants sodium stearoyl lactate (SSL) and sucrose\\u000a ester (SE) on the functional properties of films produced with polysaccharides mixtures (methylcellulose\\/glucomannan\\/pectin\\u000a in 1\\/4\\/1 ratio, respectively) and gelatin. The films were produced by the casting method and characterized for their water\\u000a vapor permeability (WVP), mechanical (tensile strength and

  7. Chitosan and gelatin based edible films: state diagrams, mechanical and permeation properties

    Microsoft Academic Search

    Ioannis S. Arvanitoyannis; Atsuyoshi Nakayama; Sei-ichi Aiba

    1998-01-01

    Films of chitosan and gelatin were prepared by casting their aqueous solutions (pH?4.0) at 60°C and evaporating at 22 or 60°C (low- and high-temperature methods, respectively). The physical (thermal, mechanical and gas\\/water permeation) properties of these composite films, plasticized with water or polyols, were studied. An increase in the total plasticizer content resulted in a considerable decrease of elasticity modulus

  8. Formulation, Casting, and Evaluation of Paraffin-Based Solid Fuels Containing Energetic and Novel Additives for Hybrid Rockets

    NASA Technical Reports Server (NTRS)

    Larson, Daniel B.; Desain, John D.; Boyer, Eric; Wachs, Trevor; Kuo, Kenneth K.; Borduin, Russell; Koo, Joseph H.; Brady, Brian B.; Curtiss, Thomas J.; Story, George

    2012-01-01

    This investigation studied the inclusion of various additives to paraffin wax for use in a hybrid rocket motor. Some of the paraffin-based fuels were doped with various percentages of LiAlH4 (up to 10%). Addition of LiAlH4 at 10% was found to increase regression rates between 7 - 10% over baseline paraffin through tests in a gaseous oxygen hybrid rocket motor. Mass burn rates for paraffin grains with 10% LiAlH4 were also higher than those of the baseline paraffin. RDX was also cast into a paraffin sample via a novel casting process which involved dissolving RDX into dimethylformamide (DMF) solvent and then drawing a vacuum on the mixture of paraffin and RDX/DMF in order to evaporate out the DMF. It was found that although all DMF was removed, the process was not conducive to generating small RDX particles. The slow boiling generated an inhomogeneous mixture of paraffin and RDX. It is likely that superheating the DMF to cause rapid boiling would likely reduce RDX particle sizes. In addition to paraffin/LiAlH4 grains, multi-walled carbon nanotubes (MWNT) were cast in paraffin for testing in a hybrid rocket motor, and assorted samples containing a range of MWNT percentages in paraffin were imaged using SEM. The fuel samples showed good distribution of MWNT in the paraffin matrix, but the MWNT were often agglomerated, indicating that a change to the sonication and mixing processes were required to achieve better uniformity and debundled MWNT. Fuel grains with MWNT fuel grains had slightly lower regression rate, likely due to the increased thermal conductivity to the fuel subsurface, reducing the burning surface temperature.

  9. Alginate- and gellan-based edible films for probiotic coatings on fresh-cut fruits.

    PubMed

    Tapia, M S; Rojas-Graü, M A; Rodríguez, F J; Ramírez, J; Carmona, A; Martin-Belloso, O

    2007-05-01

    Alginate- (2% w/v) or gellan-based (0.5%) edible films, containing glycerol (0.6% to 2.0%), N-acetylcysteine (1%), and/or ascorbic acid (1%) and citric acid (1%), were formulated and used to coat fresh-cut apple and papaya cylinders. Water vapor permeability (WVP) was significantly higher (P < 0.05) in alginate films (0.30 to 0.31 x 10(-9) g m/Pa s m2) than in the gellan ones (0.26 to 0.27 x 10(-9) g m/Pa s m2). Addition of 0.025% (w/v) sunflower oil decreased WVP of gellan films (0.20 to 0.22 x 10(-9) g m/Pa s m2). Water solubility of gellan and alginate films at 25 degrees C (0.47 to 0.59 and 0.74 to 0.79, respectively) and their swelling ratios (2.3 to 2.6 and 1.6 to 2.0, respectively) indicate their potential for coating high moisture fresh-cut fruits. Fresh-cut apple and papaya cylinders were successfully coated with 2% (w/v) alginate or gellan film-forming solutions containing viable bifidobacteria. WVP in alginate (6.31 and 5.52 x 10(-9) g m/Pa s m2) or gellan (3.65 and 4.89 x 10(-9) g m/Pa s m2) probiotic coatings of papaya and apple, respectively, were higher than in the corresponding cast films. The gellan coatings and films exhibited better water vapor properties in comparison with the alginate coatings. Values > 10(6) CFU/g B. lactis Bb-12 were maintained for 10 d during refrigerated storage of fresh-cut fruits, demonstrating the feasibility of alginate- and gellan-based edible coatings to carry and support viable probiotics on fresh-cut fruit. PMID:17995771

  10. Preparation and Properties of Biodegradable Polymer Film Based on Polyvinyl Alcohol and Tropical Fruit Waste Flour

    Microsoft Academic Search

    Ooi Xian Zhong; Hanafi Ismail; Nor Aziah Abdul Aziz; Azhar Abu Bakar

    2011-01-01

    In this study, two different types of tropical fruit waste flour, rambutan waste flour (RWF) and banana waste flour (BWF), were blended with polyvinyl alcohol (PVOH) by solution casting method. The structure of the blend film was characterised by Fourier Transform Infrared Spectroscopy. The tensile strength and elongation at break of tropical fruit waste flour-filled polyvinyl alcohol were lower, but

  11. SLIP CASTING OF MAGNESIATITANIA BODIES

    Microsoft Academic Search

    Rosenfels

    1961-01-01

    Titania is known to increase the rate of diffusion and sintering in ; pressed magnesia-titania bodies. To meet a need for dense ceramic containers ; which would hold a molten chloride eutectic, methods were developed for slip ; casting and sintering fused magnesia containing 10 wt% titania. The procedures ; were based on the Los Alamos method of slip casting

  12. Electromagnetic casting

    SciTech Connect

    Evans, J.W.; Kageyama, R. [Univ. of California, Berkeley, CA (United States); Deepak [Motorola Corp., Phoenix, AZ (United States); Cook, D.P. [Reynolds Metals Co., Richmond, VA (United States); Prasso, D.C. [Intel Corp., Aloha, OR (United States); Nishioka, S. [NKK Corp., Kawasaki (Japan)

    1995-12-31

    Electromagnetic casting (EMC) is a technology that is used extensively in the aluminum industry to cast ingots with good surface finish for subsequent rolling into consumer product. The paper reviews briefly some investigations from the eighties wherein models for EMC were developed. Then more recent work is examined wherein more realistic 3D models have been developed, the traditional studies of electromagnetic and magnetohydrodynamic phenomena have been supplemented with research on heat transport, and the stability of the metal free surface has been examined. The paper concludes with three generalizations concerning modeling that may have wider applicability than EMC.

  13. Antimicrobial nanostructured starch based films for packaging.

    PubMed

    Abreu, Ana S; Oliveira, M; de Sá, Arsénio; Rodrigues, Rui M; Cerqueira, Miguel A; Vicente, António A; Machado, A V

    2015-09-20

    Montmorillonite modified with a quaternary ammonium salt C30B/starch nanocomposite (C30B/ST-NC), silver nanoparticles/starch nanocomposite (Ag-NPs/ST-NC) and both silver nanoparticles/C30B/starch nanocomposites (Ag-NPs/C30B/ST-NC) films were produced. The nanoclay (C30B) was dispersed in a starch solution using an ultrasonic probe. Different concentrations of Ag-NPs (0.3, 0.5, 0.8 and 1.0mM) were synthesized directly in starch and in clay/starch solutions via chemical reduction method. Dispersion of C30B silicate layers and Ag-NPs in ST films characterized by X-ray and scanning electron microscopy showed that the presence of Ag-NPs enhanced clay dispersion. Color and opacity measurements, barrier properties (water vapor and oxygen permeabilities), dynamic mechanical analysis and contact angle were evaluated and related with the incorporation of C30B and Ag-NPs. Films presented antimicrobial activity against Staphylococcus aureus, Escherichia coli and Candida albicans without significant differences between Ag-NPs concentrations. The migration of components from the nanostructured starch films, assessed by food contact tests, was minor and under the legal limits. These results indicated that the starch films incorporated with C30B and Ag-NPs have potential to be used as packaging nanostructured material. PMID:26050897

  14. Porphyrin-based honeycomb films and their antibacterial activity.

    PubMed

    Wang, Yanran; Liu, Yan; Li, Guihua; Hao, Jingcheng

    2014-06-10

    Micrometer-sized porous honeycomb-patterned thin films based on hybrid complexes formed via electrostatic interaction between Mn(III) meso-tetra(4-sulfonatophenyl) porphine chloride (an acid form, {MnTPPS}) and dimethyldioctadecylammonium bromide (DODMABr). The morphology of the microporous thin films can be well regulated by controlling the concentration of MnTPPS-DODMA complexes, DODMABr, and polystyrene (PS), respectively. The formation of the microporous thin films was largely influenced by different solvents. The well-ordered microporous films of MnTPPS-DODMA complexes exhibit a more efficient antibacterial activity under visible light than those of hybrid complexes of nanoparticles modified with DODMABr, implying that well-ordered microporous films containing porphyrin composition can improve photochemical activity and more dominance in applications in biological medicine fields. PMID:24846091

  15. Microstructure/mechanical property relationship in a DS cast Ni[sub 3]Al-base alloy

    SciTech Connect

    Han, Y.F.; Wang, Y.M. (Inst. of Aeronautical Materials, Beijing (China)); Chaturvedi, M.C. (Univ. of Manitoba, Winnipeg, Manitoba (Canada). Dept. of Mechanical and Industrial Engineering)

    1993-08-01

    A Ni-Al-Mo directionally solidified (DS) casting [gamma][prime]-base superalloy, with the chemical composition (wt%) 7.5 to 8.5% Ni, 10 to 14% Al, Mo [<=] 0.15% B, has been developed for advanced gas turbine blades and vanes. The mechanical properties of this alloy have been determined by tensile tests at room temperature and in the temperature range 700 to 1,000 C and by stress-rupture tests in the temperature range 760 to 1,100 C. The microstructures of the as-cast and homogenized specimens and of specimen after creep deformation at 1,000 to 1,100 C have been examined by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and optical microscopy techniques. The results show that this alloy has a high yield strength from room temperature up to 1,100 C, excellent creep resistance at temperatures up to 1,100 C, as well as a lower density and higher melting point than currently available nickel superalloys. The microstructural observations and analysis indicate that the superior mechanical properties of this alloy may be attributed to solid solution hardening by the large molybdenum addition, second-phase strengthening by [gamma] phase and other minor phases that precipitate in various temperature ranges, the formation of a [gamma] raft structure during creep, and to the existence of high-density misfit dislocation networks at [gamma][prime]/[gamma] interface areas due to a high value of [gamma][prime]/[gamma] misfit.

  16. Inner surface roughness of complete cast crowns made by centrifugal casting machines.

    PubMed

    Ogura, H; Raptis, C N; Asgar, K

    1981-05-01

    Six variables that could affect the surface roughness of a casting were investigated. The variables were (1) type of alloy, (2) mold temperature, (3) metal casting temperature, (4) casting machine, (5) sandblasting, and (6) location of each section. It was determined that the training portion of a complete cast crown had rougher surfaces than the leading portion. Higher mold and casting temperatures produced rougher castings, and this effect was more pronounced in the case of the base metal alloy. Sandblasting reduced the roughness, but produced scratched surfaces. Sandblasting had a more pronounced affect on the surface roughness of the base metal alloy cast either at a higher mold temperature or metal casting temperature. The morphology and the roughness profile of the original cast surface differed considerably with the type of alloy used. PMID:7012322

  17. High-temperature superconducting thin-film-based electronic devices

    SciTech Connect

    Wu, X.D; Finokoglu, A.; Hawley, M.; Jia, Q.; Mitchell, T.; Mueller, F.; Reagor, D.; Tesmer, J.

    1996-09-01

    This the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The project involved optimization of processing of Y123 and Tl-2212 thin films deposited on novel substrates for advanced electronic devices. The Y123 films are the basis for development of Josephson Junctions to be utilized in magnetic sensors. Microwave cavities based on the Tl-2212 films are the basis for subsequent applications as communication antennas and transmitters in satellites.

  18. Development of Stronger and More Reliable Cast Austenitic Stainless Steels (H-Series) Based on Scientific Design Methodology

    SciTech Connect

    Muralidharan, G.; Sikka, V.K.; Pankiw, R.I.

    2006-04-15

    The goal of this program was to increase the high-temperature strength of the H-Series of cast austenitic stainless steels by 50% and upper use temperature by 86 to 140 F (30 to 60 C). Meeting this goal is expected to result in energy savings of 38 trillion Btu/year by 2020 and energy cost savings of $185 million/year. The higher strength H-Series of cast stainless steels (HK and HP type) have applications for the production of ethylene in the chemical industry, for radiant burner tubes and transfer rolls for secondary processing of steel in the steel industry, and for many applications in the heat-treating industry. The project was led by Duraloy Technologies, Inc. with research participation by the Oak Ridge National Laboratory (ORNL) and industrial participation by a diverse group of companies. Energy Industries of Ohio (EIO) was also a partner in this project. Each team partner had well-defined roles. Duraloy Technologies led the team by identifying the base alloys that were to be improved from this research. Duraloy Technologies also provided an extensive creep data base on current alloys, provided creep-tested specimens of certain commercial alloys, and carried out centrifugal casting and component fabrication of newly designed alloys. Nucor Steel was the first partner company that installed the radiant burner tube assembly in their heat-treating furnace. Other steel companies participated in project review meetings and are currently working with Duraloy Technologies to obtain components of the new alloys. EIO is promoting the enhanced performance of the newly designed alloys to Ohio-based companies. The Timken Company is one of the Ohio companies being promoted by EIO. The project management and coordination plan is shown in Fig. 1.1. A related project at University of Texas-Arlington (UT-A) is described in Development of Semi-Stochastic Algorithm for Optimizing Alloy Composition of High-Temperature Austenitic Stainless Steels (H-Series) for Desired Mechanical and Corrosion Properties (ORNL/TM-2005/81/R1). The final report on another related project at the University of Tennessee by George Pharr, Easo George, and Michael Santella has been published as Development of Combinatorial Methods for Alloy Design and Optimization (ORNL/TM-2005-133). The goal of the project was to increase the high-temperature strength by 50% and upper use temperature by 86 to 140 F (30 to 60 C) of H-Series of cast austenitic stainless steels. Meeting such a goal is expected to result in energy savings of 38 trillion Btu/year by 2020 and energy cost savings of $185 million/year. The goal of the project was achieved by using the alloy design methods developed at ORNL, based on precise microcharacterization and identification of critical microstructure/properties relationships and combining them with the modern computational science-based tools that calculate phases, phase fractions, and phase compositions based on alloy compositions. The combined approach of microcharacterization of phases and computational phase prediction would permit rapid improvement of the current alloy composition of an alloy and provide the long-term benefit of customizing alloys within grades for specific applications. The project was appropriate for the domestic industry because the current H-Series alloys have reached their limits both in high-temperature-strength properties and in upper use temperature. The desire of Duraloy's industrial customers to improve process efficiency, while reducing cost, requires that the current alloys be taken to the next level of strength and that the upper use temperature limit be increased. This project addressed a specific topic from the subject call: to develop materials for manufacturing processes that will increase high-temperature strength, fatigue resistance, corrosion, and wear resistance. The outcome of the project would benefit manufacturing processes in the chemical, steel, and heat-treating industries.

  19. Gating of Permanent Molds for ALuminum Casting

    SciTech Connect

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-03-30

    This report summarizes a two-year project, DE-FC07-01ID13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings.

  20. Buckling-based measurements of mechanical moduli of thin films

    Microsoft Academic Search

    Si-Woo Hahm; Hyun-Sik Hwang; Donyoung Kim; Dahl-Young Khang

    2009-01-01

    The buckling-based measurement of mechanical properties of material is reviewed here, which is a very useful technique for\\u000a the characterization of thin films, nano- or molecular-scale materials, etc. This method is shown to be useful to measure\\u000a elastic moduli of various thin films such as polymers, polyelectrolyte multilayers (PEM), single-wall carbon nanotubes (SWNT)\\u000a and millimeter-thick polymer network substrates. Further, it

  1. BaPbO3-based thick film resistor

    Microsoft Academic Search

    Yu-Hung Hsieh; Shen-Li Fu

    1992-01-01

    A thick-film resistor system that does not use a rare-earth or a transitional element was fabricated with semi-metallic BaPbO3 and alkali glass powders. Its characteristics are comparable to conventional thick-film resistors such as those in the RuO2-based system, while the cost is much lower. The relationship between glass-frit content and sheet resistivity is approximated by an exponential equation, and an

  2. Energy Consumption of Die Casting Operations

    SciTech Connect

    Jerald Brevick; clark Mount-Campbell; Carroll Mobley

    2004-03-15

    Molten metal processing is inherently energy intensive and roughly 25% of the cost of die-cast products can be traced to some form of energy consumption [1]. The obvious major energy requirements are for melting and holding molten alloy in preparation for casting. The proper selection and maintenance of melting and holding equipment are clearly important factors in minimizing energy consumption in die-casting operations [2]. In addition to energy consumption, furnace selection also influences metal loss due to oxidation, metal quality, and maintenance requirements. Other important factors influencing energy consumption in a die-casting facility include geographic location, alloy(s) cast, starting form of alloy (solid or liquid), overall process flow, casting yield, scrap rate, cycle times, number of shifts per day, days of operation per month, type and size of die-casting form of alloy (solid or liquid), overall process flow, casting yield, scrap rate, cycle times, number of shifts per day, days of operation per month, type and size of die-casting machine, related equipment (robots, trim presses), and downstream processing (machining, plating, assembly, etc.). Each of these factors also may influence the casting quality and productivity of a die-casting enterprise. In a die-casting enterprise, decisions regarding these issues are made frequently and are based on a large number of factors. Therefore, it is not surprising that energy consumption can vary significantly from one die-casting enterprise to the next, and within a single enterprise as function of time.

  3. Effect of crystallographic orientation on subcritical grain boundary cracking in a conventionally cast polycrystalline nickel-based superalloy.

    PubMed

    Swaminathan, Kameshwaran; Blendell, John E; Trumble, Kevin P

    2013-08-01

    The role of grain orientation and grain boundary misorientation on the formation of subcritical grain boundary cracks in creep of a conventionally cast nickel-based superalloy has been studied. The crystallographic orientations of the grains adjacent to grain boundaries normal to the tensile axis were measured using electron backscattered diffraction. The difference in the Schmid factor for the {111} <112> slip system between the grains was compared to the occurrence of grain boundary cracking. In addition, the difference in the amount of potential primary creep was calculated. The cracked grain boundaries were found to have a larger difference in Schmid factor, as well as a larger difference in potential primary creep, compared with uncracked grain boundaries. PMID:23718929

  4. Casting methods

    DOEpatents

    Marsden, Kenneth C.; Meyer, Mitchell K.; Grover, Blair K.; Fielding, Randall S.; Wolfensberger, Billy W.

    2012-12-18

    A casting device includes a covered crucible having a top opening and a bottom orifice, a lid covering the top opening, a stopper rod sealing the bottom orifice, and a reusable mold having at least one chamber, a top end of the chamber being open to and positioned below the bottom orifice and a vacuum tap into the chamber being below the top end of the chamber. A casting method includes charging a crucible with a solid material and covering the crucible, heating the crucible, melting the material, evacuating a chamber of a mold to less than 1 atm absolute through a vacuum tap into the chamber, draining the melted material into the evacuated chamber, solidifying the material in the chamber, and removing the solidified material from the chamber without damaging the chamber.

  5. Cementite Solidification in Cast Iron

    NASA Astrophysics Data System (ADS)

    Coronado, J. J.; Sinatora, A.; Albertin, E.

    2014-06-01

    Two hypereutectic cast irons (5.01 pct Cr and 5.19 pct V) were cast and the polished surfaces of test pieces were deep-etched and analyzed via scanning electron microscopy. The results show that graphite lamellae intersect the cementite and a thin austenite film nucleates and grows on the cementite plates. For both compositions, graphite and cementite can coexist as equilibrium phases, with the former always nucleating and growing first. The eutectic carbides grow from the austenite dendrites in a direction perpendicular to the primary plates.

  6. AZO thin film-based UV sensors: effects of RF power on the films

    NASA Astrophysics Data System (ADS)

    Akin, Nihan; Ceren Baskose, U.; Kinaci, Baris; Cakmak, Mehmet; Ozcelik, Suleyman

    2015-06-01

    Al-doped zinc oxide (AZO) thin films of thickness 150 nm were deposited on polyethylene terephthalate (PET) substrates by radio frequency (RF) magnetron sputtering method under various RF powers in the range of 25-100 W. Structural, morphological, optical and electrical properties of the films were investigated by X-ray diffractometer, atomic force microscope, UV-Vis spectrometer and Hall effect measurement system. All the obtained films had a highly preferred orientation along [002] direction of the c-axis perpendicular to the flexible PET substrate and had a high-quality surface. The energy band gap ( E g) values of the films varied in the range of 3.30-3.43 eV. The minimum resistivity of 1.84 × 10-4 ? cm was obtained at a 50 W RF power. The small changes in the RF power had a critical important role on the structural, optical and electrical properties of the sputtered AZO thin films on flexible PET substrate. In addition, UV sensing of the fabricated AZO thin film-based sensors was explored by using current-voltage (I-V) characteristics. The sensors were sensitive in the UV region of the electromagnetic spectrum.

  7. ZnS-nanocrystals/polypyrrole nanocomposite film based immunosensor

    NASA Astrophysics Data System (ADS)

    Mishra, Sujeet K.; Pasricha, Renu; Biradar, Ashok M.; Rajesh

    2012-01-01

    We report an electrochemically synthesized ZnS nanocrystals modified polypyrrole (PPy) nanocomposite film based immunosensor for the detection of C-reactive protein (?CRP). The ZnS-PPy composite film was characterized by transmission electron microscopy (TEM), atomic force microscopy (AFM) and electrochemical techniques. The modified film showed good biocompatibility with efficient binding to protein antibody (?CRP-Ab) molecules through ZnS nanocrystals, exhibited an attractive platform for immunosensor fabrication. The electrical and sensing properties of the polymer composite film of different thickness towards protein antigen (?CRP-Ag) were delineated. The immunosensor exhibited an impedance response to ?CRP-Ag concentration in a linear range from 10 ng to 10 ?g mL-1.

  8. A film pressure sensor based on optical fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Zhang, Zhichun; Deng, Gang; Dai, Yongbo; Liu, Yanju; Leng, Jinsong

    2010-03-01

    The measurement of pressure is essential for the design and flying controlling of aircraft. In order to measure the surface pressures of the aircraft, the common pressure tube method and Pressure sensitive paint measurement method have their own disadvantages, and are not applicable to all aircraft structures and real time pressure monitoring. In this paper, a novel thin film pressure sensor based on Fiber Bragg Grating (FBG) is proposed, using FBG measuring the tangential strain of the disk sensing film. Theoretical circle strain of the disk sensing film of the pressure sensor under pressure and temperature variation are analyzed, and the linear relationship between FBG center wavelength shift and pressure, temperature variation is gotten. The pressure and temperature calibration experiments prove the theoretical analysis. But the calibration sensing parameters are small than the calculating ones, which is caused by the constraint of optical fibre to the thin sensing film.

  9. Clamshell Casting! Stefanie Wuhrer

    E-print Network

    Wuhrer, Stefanie

    Clamshell Casting! By Stefanie Wuhrer A thesis submitted to the Faculty of Graduate Studies and Research acceptance of the thesis, Clamshell Casting! submitted by Stefanie Wuhrer Douglas Howe (Director is casting, where liquid is poured into a cast and the cast is removed once the liquid has hardened. We

  10. Initial solidification phenomena: Factors affecting heat transfer in strip casting

    NASA Astrophysics Data System (ADS)

    Nolli, Paolo

    In the last few years a few companies have announced the final stage of the commercial development of strip casting of steels. In strip casting heat extraction and productivity are limited by the thermal resistance at the interface between processed material and moving mold (rolls for twin-roll strip casters). Among many factors influencing interfacial heat transfer, films of various composition, either formed during casting or deposited before casting on the surface of the rolls, melt superheat and gas atmosphere composition can have a significantly positive or negative effect on the achieved heat transfer rate. From an industrial point view, methods to improve interfacial heat transfer rates must be found, in order to increase productivity. The objective of this research project is to assess if it is feasible to improve heat transfer rates during solidification of steel in direct contact with a copper mold: (1) by the application of thin coatings on the mold surface; (2) by adding a reactive gas species containing sulfur in the gas shrouding where casting is performed. To address the former, solidification experiments were performed with the mold surface either kept uncoated or coated with coatings of different compositions. To address the latter, the experiments were performed in gas shrouding atmospheres with or without sulphydric acid. It was observed that the resulting heat extraction rates were improved by the application of certain coatings and by the addition of H2S to the gas atmosphere. These findings prove that the application of coatings and the use of small amounts of reactive gaseous species containing sulfur may be methods to increase productivity in strip casting. The effect of superheat and the effect of naturally deposited oxides (Mn-oxide) were also evaluated experimentally. A numerical study of the effect of the critical undercooling on the productivity of a twin-roll strip caster showed that the maximum allowable casting speed can be increased by increasing the critical undercooling, which in turns can be changed by changing the composition of the coating applied on the roll surface; this increase is significant when casting thicknesses are small (less than 1 mm). Finally, a procedure, based on Scheill's method, vaporization and liquation, to predict the composition of films depositing naturally during solidification, starting from the steel composition, is proposed.

  11. Hot-Wire Deposition of Hydrogenated Nanocrystalline SiGe Films for Thin-Film Si Based Solar Cells

    E-print Network

    Deng, Xunming

    prolonged light exposure, has been successfully used in a multiple-junction solar cell and nc-Si:H based equipment producing nc-Si:H based solar cells. Two approaches could be used to reduce the total depositionHot-Wire Deposition of Hydrogenated Nanocrystalline SiGe Films for Thin-Film Si Based Solar Cells

  12. Reactively sputtered Fe3O4-based films for spintronics

    NASA Astrophysics Data System (ADS)

    Li, Peng; Jin, Chao; Mi, Wen-Bo; Bai, Hai-Li

    2013-04-01

    Half metallic polycrystalline, epitaxial Fe3O4 films and Fe3O4-based heterostructures for spintronics were fabricated by DC reactive magnetron sputtering. Large tunneling magnetoresistance was found in the polycrystalline Fe3O4 films and attributed to the insulating grain boundaries. The pinning effect of the moments at the grain boundaries leads to a significant exchange bias. Frozen interfacial/surface moments induce weak saturation of the high-field magnetoresistance. The films show a moment rotation related butterfly-shaped magnetoresistance. It was found that in the films, natural growth defects, antiphase boundaries, and magnetocrystalline anisotropy play important roles in high-order anisotropic magnetoresistance. Spin injection from Fe3O4 films to semiconductive Si and ZnO was measured to be 45% and 28.5%, respectively. The positive magnetoresistance in the Fe3O4-based heterostructures is considered to be caused by a shift of the Fe3O4 eg ? band near the interface. Enhanced magnetization was observed in Fe3O4/BiFeO3 heterostructures experimentally and further proved by first principle calculations. The enhanced magnetization can be explained by spin moments of the thin BiFeO3 layer substantially reversing into a ferromagnetic arrangement under a strong coupling that is principally induced by electronic orbital reconstruction at the interface.

  13. Preparation and characterization of TL-based superconducting thin films 

    E-print Network

    Wang, Pingshu

    1995-01-01

    A simple method for growth of Tl-based superconducting thin films is described. In this method, the precursor was prepared in a vacuum chamber by deposition of Ba, Ca and Cu metals or a Ba-Ca alloy and Cu metal. The precursor was then oxidized...

  14. Pentacene-Based Organic Thin Film Transistors for Ammonia Sensing

    Microsoft Academic Search

    Hsiao-Wen Zan; Wu-Wei Tsai; Yen-ren Lo; Yu-Mei Wu; Yuh-Shyong Yang

    2012-01-01

    Non-invasive ammonia sensors are attractive alternatives for the diagnoses of a variety of chronic diseases such as liver cirrhosis and renal failure. A low cost pentacene-based organic thin film transistor (OTFT) fabricated by a novel and simple process was demonstrated to be highly sensitive and specific for ammonia gas. Various measurement parameters that reflected OTFT device characteristics for ammonia detection

  15. Si-based multilayered print circuit board for MEMS packaging fabricated by Si deep etching, bonding, and vacuum metal casting

    NASA Astrophysics Data System (ADS)

    Murakoshi, Yoichi; Hanada, Kotaro; Li, Yaomin; Uchino, Kazuyoshi; Suzuki, Takaaki; Maeda, Ryutaro

    2001-11-01

    In our previous works, metal injection technique into small diameter (10 -100micrometers ) through holes was developed and applied for fabrication of Si based print circuit board. In the present work, we present the metal filling technology by vacuum casting into 3 dimensional through holes and trenches structure fabricated in stacked layered Si wafers prepared by fusion bonding of ICP etched Si wafers. Metal electrical feed through was successfully prepared by the method. Conventional print circuit boards have been fabricated with Epoxy resin based materials. In recent years Si is regarded as a candidate for next generation materials for print circuit board substrates, as the substrate whose thermal elongation same as the mounted chips is an ideal solution to residual stress problems in the elevated temperature application. In this report, we developed the double sided mountable stacked circuit board using Si deep etching technology and fusion bonding. This technology is expected to lead to the realization of the assembling of sensors, actuators and ICs, i.e. 3 dimensional MEMS packaging. In this report, we adopted micromachining technology to this application area and the special emphasis is placed on the low cost and reliable process development. The detailed items to be developed are shown as follows; 1) Development of Si wafer through holes penetration and trench formation by ICP etching. 2) Alignment and bonding of micromachined wafers. 3) Development of insulating layer with oxidation. 4) Development of formation of electrical feed through for stacked layers.

  16. Photoconductivity of bulk-film-based graphene sheets.

    PubMed

    Lv, Xin; Huang, Yi; Liu, Zhibo; Tian, Jianguo; Wang, Yan; Ma, Yanfeng; Liang, Jiajie; Fu, Shipeng; Wan, Xiangjian; Chen, Yongsheng

    2009-07-01

    Time-resolved photoconductivity measurements are carried out on graphene films prepared by using soluble graphene oxide. High photocurrent generation efficiency is observed for these graphene-based films, and the relationships between their photoconductivity and different preparation methods, incident light intensity, external electric field, and photon energies are investigated. Higher photoconductivity is observed with higher photon energy at same incident light intensity. By fitting the experimental data to the Onsager model, the primary quantum yields for charge separation to generate bound electron-hole pairs and the initial ion-pair thermalization separation distance are calculated. PMID:19360726

  17. Ammonia sensing characteristics of thin film based on polyelectrolyte templated polyaniline

    Microsoft Academic Search

    G. K. Prasad; T. P. Radhakrishnan; D. Sravan Kumar; M. Ghanashyam Krishna

    2005-01-01

    A novel conductive polyaniline is synthesized using poly(4-styrenesulfonate-co-maleic acid) as counter ion and template. The resistance of this electroactive polymer increases in the presence of gases such as ammonia. This transducing property is exploited and spin-cast film of this material on glass substrate is established as ammonia gas sensor module, for gas concentrations in the range 5–250ppm. In this range,

  18. Switchable mirrors based on nickel-magnesium films

    SciTech Connect

    Richardson,Thomas J.; Slack, Jonathan L.; Armitage, Robert D.; Kostecki, Robert; Farangis, Baker; Rubin, Michael D.

    2001-01-16

    A new type of electrochromic mirror electrode based on reversible uptake of hydrogen in nickel magnesium alloy films is reported. Thin,magnesium-rich Ni-Mg films prepared on glass substrates by cosputtering from Ni and Mg targets are mirror-like in appearance and have low visible transmittance. Upon exposure to hydrogen gas or on reduction in alkaline electrolyte, the films take up hydrogen and become transparent. When hydrogen is removed, the mirror properties are recovered. The transition is believed to result from reversible formation of Mg2NiH4 and MgH2. A thin overlayer of palladium was found to enhance the kinetics of hydrogen insertion and extraction,and to protect the metal surface against oxidation.

  19. Prediction of Part Distortion in Die Casting

    SciTech Connect

    R. Allen Miller

    2005-03-30

    The die casting process is one of the net shape manufacturing techniques and is widely used to produce high production castings with tight tolerances for many industries. An understanding of the stress distribution and the deformation pattern of parts produced by die casting will result in less deviation from the part design specification, a better die design and eventually more productivity and cost savings. This report presents methods that can be used to simulate the die casting process in order to predict the deformation and stresses in the produced part and assesses the degree to which distortion modeling is practical for die casting at the current time. A coupled thermal-mechanical finite elements model was used to simulate the die casting process. The simulation models the effect of thermal and mechanical interaction between the casting and the die. It also includes the temperature dependant material properties of the casting. Based on a designed experiment, a sensitivity analysis was conducted on the model to investigate the effect of key factors. These factors include the casting material model, material properties and thermal interaction between casting and dies. To verify the casting distortion predictions, it was compared against the measured dimensions of produced parts. The comparison included dimensions along and across the parting plane and the flatness of one surface.

  20. Glass forming ranges of cobalt-base thin film alloys

    Microsoft Academic Search

    H. J. Kim; I. K. Kang; J. S. Chun

    1988-01-01

    The glass forming ranges of cobalt-base binary and ternary thin film alloys containing zirconium, titanium, niobium, molybdenum, vanadium and silicon have been studied in the cobalt-rich region. The minimum solute concentration for glass formation decreased with increasing difference in atomic radii or Pauling's electronegativity, as well as the cooling rate. Cobalt-base binary alloys readily showing glass formation are shown on

  1. A comparison of the marginal adaptation of cathode-arc vapor-deposited titanium and cast base metal copings

    PubMed Central

    Wu, JC; Lai, LC; Sheets, CG; Earthman, J; Newcomb, R

    2011-01-01

    Statement of problem A new fabrication process has been developed where a titanium coping, which has a gold colored titanium nitride outer layer can be reliably fused to porcelain, but the marginal adaptation characteristics are still undetermined. Purpose The primary purpose of this study is to compare the rate of Clinically Acceptable Marginal Adaptation (CAMA-defined as a marginal gap mean ?60 ?m) of cathode-arc vapor-deposited titanium with the CAMA rate for the cast base metal copings. In addition, the study will evaluate the marginal gap scores themselves to assess their mean difference between the two study groups. Finally, the study will present two analyses of group differences in variability to support the contention that the titanium copings perform more consistently than their base metal counterparts. Material and methods Thirty-seven cathode-arc vapor-deposited titanium copings and 40 cast base metal copings were evaluated by computer-based image analysis using an optical microscope. The conventional lost wax technique was used to fabricate the 40 cast base metal copings that were 0.3 mm thick. The titanium copings were 0.3 mm thick and were formed by a collection of atomic titanium vapor onto a refractory die duplicate in a high vacuum chamber. Fifty vertical marginal gap measurements were collected from each of the 77 copings and the mean of these measurements was computed to form a gap score for each coping. Next, the gap score was compared to the 60 ?m criterion to classify each coping as to whether it did or did not achieve Clinically Acceptable Marginal Adaption (CAMA). A comparison of the CAMA rates for each type of coping was used to address the primary purpose of this study. In addition, the gap scores themselves were used to test the (one-sided) hypothesis that the mean of the titanium gap scores is smaller than the mean of the base metal gap scores. Finally, the assertion that the titanium copings provide more consistency in their marginal gap performance was tested in two ways. First, the means of the titanium gap scores were compared to the means of the marginal gap scores for the base metal copings. Second, the standard deviations of the marginal gap scores for the titanium copings were compared with those for the base metal copings. Results Statistical comparison of the CAMA rates for each type of coping showed that the CAMA criterion was achieved by 24 of the 37 (64.86%) titanium copings, while 19 of the 40 (47.50%) base metal copings met this same standard. Noninferiority of the titanium copings was established by the 2-sided 90% Confidence Interval for the 17.36% difference in these rates (?0.95%, 35.68%) and noninferiority of titanium coping adaption was also demonstrated by the Wald Test rejection of the tentative hypothesis of inferiority (Z-score=1.9191, one-sided p=0.0275). The mean of the vertical marginal gap scores for the titanium copings (56.9025) was significantly less than the mean of the marginal gap scores for the base metal copings (71.9041) as shown by the Satterthwaite t-score=?2.29 (one-sided p=0.0126). To compare the adaption consistency of the titanium copings to the base metal counterparts the difference between the variance of the marginal gap scores for the titanium copings (594.843) and the variance of the marginal gap scores for the base metal copings (1510.901) was found to be statistically significant (Folded-F test score=2.63, p=0.0042). Our second method for showing that the titanium copings performed more consistently than the base metal comparisons was to use a one-sided test to show that the mean of the standard deviations of the vertical gap measurements for each titanium coping (29.9835) was significantly lower than the mean of the standard deviations of the vertical gap measurements for each base metal coping (36.1332). This test produced a Satterthwaite’s t-score of ?2.24 (one-sided p=0.0141), indicating the titanium adaption was significantly more consistent. Conclusions Cathode-arc vapor deposited titanium

  2. Fabrication characteristics of an anode-supported thin-film electrolyte fabricated by the tape casting method for IT-SOFC

    Microsoft Academic Search

    Jung-Hoon Song; Sun-Il Park; Jong-Ho Lee; Ho-Sung Kim

    2008-01-01

    An anode-supported yttria-stabilized zirconia (YSZ) electrolyte was fabricated using tape casting and co-sintering techniques for use in a solid oxide fuel cell (SOFC). Nickel\\/YSZ, lanthanum strontium manganite (La0.85Sr0.15MnO3) and 8mol% Y2O3–ZrO2 were used for the anode, the cathode and the electrolyte, respectively. The anode-supported electrolyte was prepared with a tape casting technique followed by hot pressing lamination. Co-sintering between the

  3. Filmless versus film-based systems in radiographic examination costs: an activity-based costing method

    PubMed Central

    2011-01-01

    Background Since the shift from a radiographic film-based system to that of a filmless system, the change in radiographic examination costs and costs structure have been undetermined. The activity-based costing (ABC) method measures the cost and performance of activities, resources, and cost objects. The purpose of this study is to identify the cost structure of a radiographic examination comparing a filmless system to that of a film-based system using the ABC method. Methods We calculated the costs of radiographic examinations for both a filmless and a film-based system, and assessed the costs or cost components by simulating radiographic examinations in a health clinic. The cost objects of the radiographic examinations included lumbar (six views), knee (three views), wrist (two views), and other. Indirect costs were allocated to cost objects using the ABC method. Results The costs of a radiographic examination using a filmless system are as follows: lumbar 2,085 yen; knee 1,599 yen; wrist 1,165 yen; and other 1,641 yen. The costs for a film-based system are: lumbar 3,407 yen; knee 2,257 yen; wrist 1,602 yen; and other 2,521 yen. The primary activities were "calling patient," "explanation of scan," "take photographs," and "aftercare" for both filmless and film-based systems. The cost of these activities cost represented 36.0% of the total cost for a filmless system and 23.6% of a film-based system. Conclusions The costs of radiographic examinations using a filmless system and a film-based system were calculated using the ABC method. Our results provide clear evidence that the filmless system is more effective than the film-based system in providing greater value services directly to patients. PMID:21961846

  4. A space imaging concept based on a 4m structured spun-cast borosilicate monolithic primary mirror

    NASA Astrophysics Data System (ADS)

    West, S. C.; Bailey, S. H.; Bauman, S.; Cuerden, B.; Granger, Z.; Olbert, B. H.

    2010-07-01

    Lockheed Martin Corporation (LMC) tasked The University of Arizona Steward Observatory (UASO) to conduct an engineering study to examine the feasibility of creating a 4m space telescope based on mature borosilicate technology developed at the UASO for ground-based telescopes. UASO has completed this study and concluded that existing launch vehicles can deliver a 4m monolithic telescope system to a 500 km circular orbit and provide reliable imagery at NIIRS 7-8. An analysis of such an imager based on a lightweight, high-performance, structured 4m primary mirror cast from borosilicate glass is described. The relatively high CTE of this glass is used to advantage by maintaining mirror shape quality with a thermal figuring method. Placed in a 290 K thermal shroud (similar to the Hubble Space Telescope), the orbit averaged figure surface error is 6nm rms when earth-looking. Space-looking optical performance shows that a similar thermal conditioning scheme combined with a 270 K shroud achieves primary mirror distortion of 10 nm rms surface. Analysis shows that a 3-point bipod mount will provide launch survivability with ample margin. The primary mirror naturally maintains its shape at 1g allowing excellent end-to-end pre-launch testing with e.g. the LOTIS 6.5m Collimator. The telescope includes simple systems to measure and correct mirror shape and alignment errors incorporating technologies already proven on the LOTIS Collimator. We have sketched a notional earth-looking 4m telescope concept combined with a wide field TMA concept into a DELTA IV or ATLAS 552 EELV fairing. We have combined an initial analysis of launch and space performance of a special light-weighted honeycomb borosilicate mirror (areal density 95 kg/m2) with public domain information on the existing launch vehicles.

  5. Humidity sensors based on polymer thin films

    Microsoft Academic Search

    Y Sakai; Y Sadaoka; M Matsuguchi

    1996-01-01

    Studies on humidity sensors fabricated with organic polymers for the last 10 years are reviewed. Several useful methods for improving the characteristics of humidity sensors based on polymers are proposed. In the case of a resistive-type sensor, cross-linking of hydrophilic polymers or formation of interpenetrated polymer networks with a hydrophobic polymer makes the hydrophilic polymers durable at high humidities. Graft

  6. Formation of thin film Tl-based high-Tc? superconducting oxides from amorphous alloy precursors

    E-print Network

    Williams, John Charles

    1991-01-01

    . Magnetoresistance 3. Jc Measurement for Film BF01890. 4. Resistivity and Hall Effect Measurements IV. CONCLUSION REFERENCES. . VITA LIST OF TABLES 1. 1 Tl-based Superconductor Metal Ion Stacking Sequences. . . . 3. 1 Alloy Pellets. 3. 2 Film Production.... Fundamental Properties. 2. Perovskite Crystal Structure. 3. Perovskite Crystal Structure Modifications 4, Structure of Thallate Superconductors . . B. Thallium-based Thin Film Superconductors. . . . 1. Tl-based Thin Film Production Methods. . . . 2...

  7. The partitioning of refactory metal elements in hafnium-modified cast nickel- base superalloys

    Microsoft Academic Search

    J. M. Dahl; W. F. Danesi; R. G. Dunn

    1973-01-01

    Data from the electron microprobe have been used to elucidate the role of hafnium in altering the microstructure of the nickel-base\\u000a superalloys B-1900, Alloy 713 LC, Udimet 700, and Mar-M246. The addition of about 1.3 to 2.0 pct Hf to these alloys improves\\u000a their strength and ductility at both room temperature and 760°C. The data indicate that hafnium partitions to

  8. Fabrication, Characterization, and Applications of Graphene-based Flexible Films

    NASA Astrophysics Data System (ADS)

    Naik, Gautam

    Scientific interest in the field of nanotechnology has increased multifold since the discovery of multi-walled carbon nanotubes in the early 1990s. This further received a tremendous boost with the isolation of graphene, a single layer of sp2-hybridized carbon atoms, in 2004. Graphene has exceptional mechanical and electrical properties, which makes it an attractive candidate for electronics and composites. In order to realize the implementation of graphene for such applications, scalable production of graphene-based materials needs to be accomplished. Graphene oxide, the product of oxidation and exfoliation of graphite, is a promising precursor for bulk-production of graphene and graphene-like materials. The oxidation of graphite to synthesize graphene oxide results in the decoration of the basal plane of graphene with oxygen-containing functional groups. The presence of these functional groups makes graphene oxide strongly hydrophilic, making it soluble in water and a good candidate for solution-based processing. This hydrophilic nature of graphene oxide can also be utilized to fabricate highly sensitive and flexible humidity sensors, the results of which are included in this research. The fabricated humidity sensors show high sensitivity and a fast response time. A difference in response is observed at low and high humidity, with hysteresis observed at high humidity levels. A method to "reset" the sensor and a mechanism to explain the response is also proposed. Although the hydrophilic nature of graphene oxide makes it suitable for bulk processing, the presence of functional groups makes it defective and insulating. Graphene oxide needs to be reduced to make it electrically active. Numerous methodologies proposed for reduction of graphene oxide result in the simultaneous reduction and exfoliation of graphene oxide films. But for instances where flexible graphene films are required for certain applications, a method for reduction of graphene oxide flexible films while maintaining its structural integrity is essential. A method for thermal reduction of flexible graphene oxide films under stress confinement is described. Reduction of graphene oxide flexible films is carried out in a MTS testing machine equipped with a controlled atmosphere furnace. The reduced films show higher carbon-to-oxygen ratio and an increase in conductivity by over five orders in magnitude. An electromechanical application of these reduced graphene oxide films for strain sensing is also demonstrated, with high and tunable gauge factors, which are three orders of magnitude higher than conventional metal foil strain gauges. A mechanism and model to explain the strain sensing is also described. Lastly, quantification of the degree of photoreduction and characterization of thermal properties of graphene-based flexible films is conducted. The temperature distribution on the surface of the graphene oxide flexible film is recorded using an infrared thermal camera. Effective reduction using a laser is achieved in a very short duration at low power and temperature. The thermal properties are calculated using the transient temperature response, and are found to be orders of magnitude lower than pristine graphene. The photoreduction method is a promising route for roll-to-roll production of reduced graphene oxide flexible films.

  9. Acetone sensor based on Film Bulk Acoustic Resonator

    Microsoft Academic Search

    Xiaotun Qiu; Rui Tang; Jie Zhu; Hongyu Yu; Jon Oiler; Ziyu Wang

    2010-01-01

    This paper described acetone sensing using ZnO based Film Bulk Acoustic Resonator (FBAR). The resonant frequency of the FBAR increased as the concentration of acetone increased. The detection limit of acetone was around 4 ppm. The density decrease of the ZnO induced by releasing carbon dioxide generated from the reaction between acetone and the adsorbed oxygen ions on the ZnO

  10. Titania pigment particles dispersion in water-based paint films

    Microsoft Academic Search

    Saeed Farrokhpay; Gayle E. Morris; Daniel Fornasiero; Peter Self

    2006-01-01

    The distribution of titanian pigment, in dry water-based paint films in the presence of polymeric dispeersants containing\\u000a different functional groups was investigated. The polymeric dispersants chosen were polyacrylic acid and polyacrylamide momo-and\\u000a copolymers modified with hydroxyl and\\/or carboxylate groups. Atomic force microscopy (AFM) and transmission electron microscopy\\u000a (TEM) were used to assess the distribution of the titania pigment particles in

  11. Biomimetic membrane arrays on cast hydrogel supports.

    PubMed

    Roerdink Lander, Monique; Ibragimova, Sania; Rein, Christian; Vogel, Jörg; Stibius, Karin; Geschke, Oliver; Perry, Mark; Hélix-Nielsen, Claus

    2011-06-01

    Lipid bilayers are intrinsically fragile and require mechanical support in technical applications based on biomimetic membranes. Tethering the lipid bilayer membranes to solid substrates, either directly through covalent or ionic substrate-lipid links or indirectly on substrate-supported cushions, provides mechanical support but at the cost of small molecule transport through the membrane-support sandwich. To stabilize biomimetic membranes while allowing transport through a membrane-support sandwich, we have investigated the feasibility of using an ethylene tetrafluoroethylene (ETFE)/hydrogel sandwich as the support. The sandwich is realized as a perforated surface-treated ETFE film onto which a hydrogel composite support structure is cast. We report a simple method to prepare arrays of lipid bilayer membranes with low intrinsic electrical conductance on the highly permeable, self-supporting ETFE/hydrogel sandwiches. We demonstrate how the ETFE/hydrogel sandwich support promotes rapid self-thinning of lipid bilayers suitable for hosting membrane-spanning proteins. PMID:21526805

  12. Identification of Thin Film Stress Based on Mindlin-Reissner Plate Finite Element Method

    Microsoft Academic Search

    Kang Fu

    2012-01-01

    In the present work, thin film stress identification procedure based on finite element method is developed. A model of two layer composite plates with thin film stress is established in the frame work of the Mindlin-Reissner plate theory. A strategy of least square method with regularization based on the derivations of smoothed elemental thin film stress is introduced to identify

  13. Synthesis, characterization and antibacterial activity of biodegradable films prepared from Schiff bases of zein.

    PubMed

    Soliman, E A; Khalil, A A; Deraz, S F; El-Fawal, G; Elrahman, S Abd

    2014-10-01

    Pure zein is known to be very hydrophobic, but is still inappropriate for coating and film applications because of their brittle nature. In an attempt to improve the flexibility and the antimicrobial activity of these coatings and films, Chemical modification of zein through forming Schiff bases with different phenolic aldhydes was tried. Influence of this modifications on mechanical, topographical, wetting properties and antimicrobial activity of zein films were evaluated. The chemical structure of the Schiff bases films were characterized by ATR-FTIR spectroscopy. The results indicate an improvement in mechanical properties with chemically modification of zein to form Schiff bases leading to a reduction in the elastic modulus. An increase in the elongation at break has been observed, but with slight influence on tensile strength. Plasticized zein films have similar initial contact angle (?40°). An increase in reaction temperature and time increases film's affinity towards water. As shown by contact angle measurements, a noticeable relation was found between film composition and the hydrophilicity. Surface topography also varied by forming Schiff bases, becoming rougher than zein-based films. The antibacterial activities of zein and Schiff bases of zein-based films were investigated against gram-positive bacteria (Listeria innocua, Listeria monocytogenes, Bacillus cereus and Clostridium sporogenes) and gram-negative bacteria (Escherichia coli, Yersinia enterocolitica and Salmonella enterica). It was found that the antibacterial activity of the Schiff bases-based films was more effective than that of zein-based films. PMID:25328181

  14. The nucleation of Fe-Rich phases on oxide films in Al11.5Si0.4Mg cast alloys

    Microsoft Academic Search

    X. Cao; J. Campbell

    2003-01-01

    The microstructures of Al-11.5Si-0.4Mg alloys with various Fe and Mn contents have been studied to investigate the potential\\u000a influence of oxide films on the precipitation of Fe-rich phases from the liquid metal. Oxide films are incorporated into melts\\u000a by an entrainment process. This is an enfolding mechanism of incorporation. Folded oxide films in melts have two sides: the\\u000a dry unbonded

  15. Optical properties of a long dynamic range chemical UV dosimeter based on solvent cast polyvinyl chloride (PVC).

    PubMed

    Amar, Abdurazaq; Parisi, Alfio V

    2013-11-01

    The dosimetric properties of the recently introduced UV dosimeter based on 16 ?m PVC film have been fully characterised. Drying the thin film in air at 50 °C for at least 28 days was found to be necessary to minimise the temperature effects on the dosimeter response. This research has found that the dosimeter response, previously reported to be mainly to UVB, has no significant dependence on either exposure temperature or dose rate. The dosimeter has negligible dark reaction and responds to the UV radiation with high reproducibility. The dosimeter angular response was found to have a similar pattern as the cosine function but deviates considerably at angles larger than 70°. Dose response curves exhibit monotonically increasing shape and the dosimeter can measure more than 900 SED. This is about 3 weeks of continuous exposure during summer at subtropical sites. Exposures measured by the PVC dosimeter for some anatomical sites exposed to solar radiation for twelve consecutive days were comparable with those concurrently measured by a series of PPO dosimeters and were in line with earlier results reported in similar studies. PMID:24084259

  16. Informing Selection of Nanomaterial Concentrations for ToxCast in Vitro Testing Based on Occupational Exposure Potential

    PubMed Central

    Brown, James S.; Wang, Amy; Houck, Keith A.; Dix, David J.; Kavlock, Robert J.; Hubal, Elaine A. Cohen

    2011-01-01

    Background: Little justification is generally provided for selection of in vitro assay testing concentrations for engineered nanomaterials (ENMs). Selection of concentration levels for hazard evaluation based on real-world exposure scenarios is desirable. Objectives: Our goal was to use estimates of lung deposition after occupational exposure to nanomaterials to recommend in vitro testing concentrations for the U.S. Environmental Protection Agency’s ToxCast™ program. Here, we provide testing concentrations for carbon nanotubes (CNTs) and titanium dioxide (TiO2) and silver (Ag) nanoparticles (NPs). Methods: We reviewed published ENM concentrations measured in air in manufacturing and R&D (research and development) laboratories to identify input levels for estimating ENM mass retained in the human lung using the multiple-path particle dosimetry (MPPD) model. Model input parameters were individually varied to estimate alveolar mass retained for different particle sizes (5–1,000 nm), aerosol concentrations (0.1 and 1 mg/m3), aspect ratios (2, 4, 10, and 167), and exposure durations (24 hr and a working lifetime). The calculated lung surface concentrations were then converted to in vitro solution concentrations. Results: Modeled alveolar mass retained after 24 hr is most affected by activity level and aerosol concentration. Alveolar retention for Ag and TiO2 NPs and CNTs for a working-lifetime (45 years) exposure duration is similar to high-end concentrations (~ 30–400 ?g/mL) typical of in vitro testing reported in the literature. Conclusions: Analyses performed are generally applicable for providing ENM testing concentrations for in vitro hazard screening studies, although further research is needed to improve the approach. Understanding the relationship between potential real-world exposures and in vitro test concentrations will facilitate interpretation of toxicological results. PMID:21788197

  17. Initial solidification phenomena: Factors affecting heat transfer in strip casting

    Microsoft Academic Search

    Paolo Nolli

    2007-01-01

    In the last few years a few companies have announced the final stage of the commercial development of strip casting of steels. In strip casting heat extraction and productivity are limited by the thermal resistance at the interface between processed material and moving mold (rolls for twin-roll strip casters). Among many factors influencing interfacial heat transfer, films of various composition,

  18. MEMS-based thin-film fuel cells

    DOEpatents

    Jankowksi, Alan F.; Morse, Jeffrey D.

    2003-10-28

    A micro-electro-mechanical systems (MEMS) based thin-film fuel cells for electrical power applications. The MEMS-based fuel cell may be of a solid oxide type (SOFC), a solid polymer type (SPFC), or a proton exchange membrane type (PEMFC), and each fuel cell basically consists of an anode and a cathode separated by an electrolyte layer. Additionally catalyst layers can also separate the electrodes (cathode and anode) from the electrolyte. Gas manifolds are utilized to transport the fuel and oxidant to each cell and provide a path for exhaust gases. The electrical current generated from each cell is drawn away with an interconnect and support structure integrated with the gas manifold. The fuel cells utilize integrated resistive heaters for efficient heating of the materials. By combining MEMS technology with thin-film deposition technology, thin-film fuel cells having microflow channels and full-integrated circuitry can be produced that will lower the operating temperature an will yield an order of magnitude greater power density than the currently known fuel cells.

  19. Naphthacene Based Organic Thin Film Transistor With Rare Earth Oxide

    SciTech Connect

    Konwar, K. [Department of Physics, Digboi College, Digboi-786171, Assam (India); Baishya, B. [Department of Physics, Dibrugarh University, Dibrugarh-786004, Assam (India)

    2010-12-01

    Naphthacene based organic thin film transistors (OTFTs) have been fabricated using La{sub 2}O{sub 3}, as the gate insulator. All the OTFTs have been fabricated by the process of thermal evaporation in vacuum on perfectly cleaned glass substrates with aluminium as source-drain and gate electrodes. The naphthacene film morphology on the glass substrate has been studied by XRD and found to be polycrystalline in nature. The field effect mobility, output resistance, amplification factor, transconductance and gain bandwidth product of the OTFTs have been calculated by using theoretical TFT model. The highest value of field effect mobility is found to be 0.07x10{sup -3} cm{sup 2}V{sup -1}s{sup -1} for the devices annealed in vacuum at 90 deg. C for 5 hours.

  20. Large displacement vertical translational actuator based on piezoelectric thin films

    PubMed Central

    Qiu, Zhen; Pulskamp, Jeffrey S; Lin, Xianke; Rhee, Choong-Ho; Wang, Thomas; Polcawich, Ronald G; Oldham, Kenn

    2014-01-01

    A novel vertical translational microactuator based on thin-film piezoelectric actuation is presented, using a set of four compound bend-up/bend-down unimorphs to produce translational motion of a moving platform or stage. The actuation material is a chemical-solution deposited lead–zirconate–titanate (PZT) thin film. Prototype designs have shown as much as 120 ?m of static displacement, with 80–90 ?m displacements being typical, using four 920 ?m long by 70 ?m legs. Analytical models are presented that accurately describe nonlinear behavior in both static and dynamic operation of prototype stages when the dependence of piezoelectric coefficients on voltage is known. Resonance of the system is observed at a frequency of 200 Hz. The large displacement and high bandwidth of the actuators at low-voltage and low-power levels should make them useful to a variety of optical applications, including endoscopic microscopy. PMID:25506130

  1. Identification and annotation of erotic film based on content analysis

    NASA Astrophysics Data System (ADS)

    Wang, Donghui; Zhu, Miaoliang; Yuan, Xin; Qian, Hui

    2005-02-01

    The paper brings forward a new method for identifying and annotating erotic films based on content analysis. First, the film is decomposed to video and audio stream. Then, the video stream is segmented into shots and key frames are extracted from each shot. We filter the shots that include potential erotic content by finding the nude human body in key frames. A Gaussian model in YCbCr color space for detecting skin region is presented. An external polygon that covered the skin regions is used for the approximation of the human body. Last, we give the degree of the nudity by calculating the ratio of skin area to whole body area with weighted parameters. The result of the experiment shows the effectiveness of our method.

  2. Simulation-based selection of optimum pressure die-casting process parameters using neural nets and genetic algorithms

    Microsoft Academic Search

    A. Krimpenis; P. G. Benardos; G.-C. Vosniakos; A. Koukouvitaki

    2006-01-01

    Pressure die-casting condition selection mainly relies on the experience and expertise of individuals working in production industries. Systematic knowledge accumulation regarding the manufacturing process is essential in order to obtain optimal process conditions. It is not safe a priori to presume that rules of thumb, which are widely used on the shop floor, always lead to fast prototype production calibration

  3. Development of Bismuth-based Lead-free Piezoelectric Materials: Thin Film Piezoelectric Materials via PVD and CSD Routes

    NASA Astrophysics Data System (ADS)

    Jeon, Yu Hong

    Piezoelectric materials have been widely used in electromechanical actuators, sensors, and ultrasonic transducers. Among these materials, lead zirconate titanate Pb(Zr1-xTix)O3 (PZT) has been primarily investigated due to its excellent piezoelectric properties. However, environmental concerns due to the toxicity of PbO have led to investigations into alternative materials systems. Bismuth-based perovskite piezoelectric materials such as (Bi0.5,Na0.5)TiO3 - (Bi0.5K 0.5)TiO3 (BNT - BKT), (Bi0.5,Na0.5 )TiO3 - (Bi0.5K0.5)TiO3 - BaTiO3(BNT - BKT - BT), (Bi0.5K 0.5)TiO3 - Bi(Zn0.5,Ti0.5)O 3 (BKT - BZT), and (Bi0.5,Na0.5)TiO 3 - (Bi0.5K0.5)TiO3 - Bi(Mg 0.5,Ti0.5)O3 (BNT - BKT - BMgT) have been explored as potential alternatives to PZT. These materials systems have been extensively studied in bulk ceramic form, however many of the ultimate applications will be in thin film embodiments (i.e., microelectromechanical systems). For this reason, in this thesis these lead-free piezoelectrics are synthesized in thin film form to understand the structure-property-processing relationships and their impact on the ultimate device response. Fabrication of high quality of 0.95BKT - 0.05BZT thin films on platinized silicon substrates was attempted by pulsed laser deposition. Due to cation volatility, deposition parameters such as substrate temperature, deposition pressure, and target-substrate distance, as well as target overdoping were explored to achieve phase pure materials. This route led to high dielectric loss, indicative of poor ferroelectric behavior. This was likely a result of the poor thin film morphology observed in films deposited via this method. Subsequently, 0.8BNT - 0.2BKT, 85BNT - 10BKT - 5BT, and 72.5BNT - 22.5BKT - 5BMgT (near morphotropic phase boundary composition) were synthesized via chemical solution deposition. To compensate the loss of A-site cations, overdoped precursor solutions were prepared. Crystallization after each spin cast layer were required to produce phase pure material. Good permittivities and low dielectric loss over the frequency range of 100 Hz to 1 MHz were obtained. Dependent upon annealing conditions, various film morphologies and compositional distributions were observed via electron microscopy and composition measurements. As opposed to previously reported work, good ferroelectric response at low frequency (200 Hz) were found. For BNT - BKT - BMgT, the maximum polarization was over 50 ?C/cm2 with high d33,fof 75 pm/V were obtained. Additionally, the extrinsic and intrinsic contributions to the dielectric response for solution-derived BNT - BKT and BNT - BKT - BMgT films were studied via Rayleigh analysis. For sub-switching fields a good agreement between predicted polarization behavior from Rayleigh analysis and experimentally measured polarization indicated the validity of this approach for BNT-based thin films. Results of this thesis proved that high quality bismuth-based piezoelectric thin films with good electrical response can be fabricated with suppression of cation volatility for various processing conditions. Furthermore, these thin films can be considered as alternatives to PZT thin films as potential candidates for piezoelectric-based microelectromechanical systems (MEMS).

  4. Usefulness of gel-casting method in the fabrication of nonstoichiometric CaZrO{sub 3}-based electrolytes for high temperature application

    SciTech Connect

    Dudek, Magdalena [AGH - University of Science and Technology, Faculty of Energy and Fuels, 30-059 Cracow (Poland)

    2009-09-15

    Hydrogels obtained from lower toxicity monomers of N-(hydroxymethyl)acrylamide and N,N'-methylenebisacrylamide were applied to form nonstoichiometric CaZrO{sub 3}-based electrolytes. A coprecipitation-calcination method with ((NH{sub 4}){sub 2}C{sub 2}O{sub 4}) in concentrated NH{sub 3} aqueous solution was used to synthesise CaZrO{sub 3} involving 51 mol.% CaO (CZ-51) powder. The gas-tight CaZrO{sub 3}-based rods were prepared by the gel-casting method with 45 vol.% suspension and then sintered at 1500 deg. C-2 h. It was found that in low oxygen partial pressure, the nonstoichiometric CaZrO{sub 3} obtained by gel-casting method were pure oxide ion conductors. These samples exhibited comparable electrical conductivity values to isostatically compressed pellets starting from the same powder. The results of experiments on thermochemical stability of CZ-51 gel-cast shapes at high temperatures in air or gas mixtures involving 2-50 vol.% H{sub 2}, as well as the corrosion resistance in exhaust gases from a self-ignition engine were also presented and discussed. The thermal resistance of CaZrO{sub 3} obtained rods against molten nickel or iron was also examined. Based upon these investigations, it is evident that only in hydrogen-rich gas atmospheres can the stability of CaZrO{sub 3} shapes be limited due to the presence of CaO precipitation as a second phase. The nonstoichiometric CaZrO{sub 3} (CZ-51) gel-cast materials were also tested in solid galvanic cells, designed to study thermodynamic properties of oxide materials, important for SOFC and energy technology devices. In this way, the Gibbs energy of NiM{sub 2}O{sub 4}, M = Cr, Fe, at 650-1000 deg. C was determined. The CaZrO{sub 3} involving 51 mol.% CaO gel-cast sintered shapes seems to be promising solid electrolytes for electrochemical oxygen probes in control of metal processing and thermodynamic studies of materials important for the development of the energy industry.

  5. INTERIOR VIEW WITH CASTING MACHINE AND CASTING FOREMAN OBSERVING OPERATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW WITH CASTING MACHINE AND CASTING FOREMAN OBSERVING OPERATION TO ENSURE MAXIMUM PRODUCTION AND QUALITY. - McWane Cast Iron Pipe Company, Pipe Casting Area, 1201 Vanderbilt Road, Birmingham, Jefferson County, AL

  6. Effects of the Exposure to Corrosive Salts on the Frictional Behavior of Gray Cast Iron and a Titanium-Based Metal Matrix Composite

    SciTech Connect

    Blau, Peter Julian [ORNL; Truhan, Jr., John J [ORNL; Kenik, Edward A [ORNL

    2007-01-01

    The introduction of increasingly aggressive road-deicing chemicals has created significant and costly corrosion problems for the trucking industry. From a tribological perspective, corrosion of the sliding surfaces of brakes after exposure to road salts can create oxide scales on the surfaces that affect friction. This paper describes experiments on the effects of exposure to sodium chloride and magnesium chloride sprays on the transient frictional behavior of cast iron and a titanium-based composite sliding against a commercial brake lining material. Corrosion scales on cast iron initially act as abrasive third-bodies, then they become crushed, spread out, and behave as a solid lubricant. The composition and subsurface microstructures of the corrosion products on the cast iron were analyzed. Owing to its greater corrosion resistance, the titanium composite remained scale-free and its frictional response was markedly different. No corrosion scales were formed on the titanium composite after aggressive exposure to salts; however, a reduction in friction was still observed. Unlike the crystalline sodium chloride deposits that tended to remain dry, hygroscopic magnesium chloride deposits absorbed ambient moisture from the air, liquefied, and retained a persistent lubricating effect on the titanium surfaces.

  7. Effect of casting methods on accuracy of peridental restorations.

    PubMed

    Finger, W; Kota, K

    1982-06-01

    The present study has shown that the accuracy of peridental gold alloy castings depends 1) on the type of casting machine used, 2) on the diameter of the casting sprue, and 3) on the strength properties of the investment material. The dependence between the accuracy and the three factors mentioned is based on erosion of the investment mold by the inflow of the liquid casting alloy. The vacuum casting technique proved to be a more gentle casting method than centrifugal and vacuum/pressure techniques. PMID:7051263

  8. Simultaneous Modification of Bottom-Contact Electrode and Dielectric Surfaces for Organic Thin-Film Transistors Through Single-Component Spin-Cast Monolayers

    SciTech Connect

    O Acton; M Dubey; t Weidner; K OMalley; T Kim; G Ting; D Hutchins; J Baio; T Lovejoy; et al.

    2011-12-31

    An efficient process is developed by spin-coating a single-component, self-assembled monolayer (SAM) to simultaneously modify the bottom-contact electrode and dielectric surfaces of organic thin-film transistors (OTFTs). This efficient interface modification is achieved using n-alkyl phosphonic acid based SAMs to prime silver bottom-contacts and hafnium oxide (HfO{sub 2}) dielectrics in low-voltage OTFTs. Surface characterization using near edge X-ray absorption fine structure (NEXAFS) spectroscopy, X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, atomic force microscopy (AFM), and spectroscopic ellipsometry suggest this process yields structurally well-defined phosphonate SAMs on both metal and oxide surfaces. Rational selection of the alkyl length of the SAM leads to greatly enhanced performance for both n-channel (C60) and p-channel (pentacene) based OTFTs. Specifically, SAMs of n-octylphos-phonic acid (OPA) provide both low-contact resistance at the bottom-contact electrodes and excellent interfacial properties for compact semiconductor grain growth with high carrier mobilities. OTFTs based on OPA modifi ed silver electrode/HfO{sub 2} dielectric bottom-contact structures can be operated using < 3V with low contact resistance (down to 700 Ohm-cm), low subthreshold swing (as low as 75 mV dec{sup -1}), high on/off current ratios of 107, and charge carrier mobilities as high as 4.6 and 0.8 cm{sup 2} V{sup -1} s{sup -1}, for C60 and pentacene, respectively. These results demonstrate that this is a simple and efficient process for improving the performance of bottom-contact OTFTs.

  9. C++ Dynamic Cast in Autonomous Space Systems

    Microsoft Academic Search

    Damian Dechev; Rabi N. Mahapatra; Bjarne Stroustrup; David Wagner

    2008-01-01

    The dynamic cast operation allows flexibility in the design and use of data management facilities in object- oriented programs. Dynamic cast has an important role in the implementation of the Data Management Services (DMS) of the Mission Data System Project (MDS), the Jet Propulsion Laboratory's experimental work for providing a state-based and goal-oriented unified architecture for test- ing and development

  10. Comparative Evaluation of Marginal Accuracy of a Cast Fixed Partial Denture Compared to Soldered Fixed Partial Denture Made of Two Different Base Metal Alloys and Casting Techniques: An In vitro Study.

    PubMed

    Jei, J Brintha; Mohan, Jayashree

    2014-03-01

    The periodontal health of abutment teeth and the durability of fixed partial denture depends on the marginal adaptation of the prosthesis. Any discrepancy in the marginal area leads to dissolution of luting agent and plaque accumulation. This study was done with the aim of evaluating the accuracy of marginal fit of four unit crown and bridge made up of Ni-Cr and Cr-Co alloys under induction and centrifugal casting. They were compared to cast fixed partial denture (FPD) and soldered FPD. For the purpose of this study a metal model was fabricated. A total of 40 samples (4-unit crown and bridge) were prepared in which 20 Cr-Co samples and 20 Ni-Cr samples were fabricated. Within these 20 samples of each group 10 samples were prepared by induction casting technique and other 10 samples with centrifugal casting technique. The cast FPD samples obtained were seated on the model and the samples were then measured with travelling microscope having precision of 0.001 cm. Sectioning of samples was done between the two pontics and measurements were made, then the soldering was made with torch soldering unit. The marginal discrepancy of soldered samples was measured and all findings were statistically analysed. The results revealed minimal marginal discrepancy with Cr-Co samples when compared to Ni-Cr samples done under induction casting technique. When compared to cast FPD samples, the soldered group showed reduced marginal discrepancy. PMID:24605006

  11. Electrospun aggregation-induced emission active POSS-based porous copolymer films for detection of explosives.

    PubMed

    Zhou, Hui; Ye, Qun; Neo, Wei Teng; Song, Jing; Yan, Hong; Zong, Yun; Tang, Ben Zhong; Hor, T S Andy; Xu, Jianwei

    2014-11-18

    Electrospun aggregation-induced emission (AIE)-active polyhedral oligomeric silsesquioxane (POSS)-based copolymer films exhibit an approximately 9-fold increase in response to explosive vapors compared to dense films although porous copolymer films have a thickness as high as 560 ± 60 nm. PMID:25252003

  12. Highlights on photocathodes based on thin films prepared by pulsed laser deposition

    Microsoft Academic Search

    A. Lorusso; F. Gontad; A. Perrone; N. Stankova

    2011-01-01

    We review the current status of metallic photocathodes based on thin films prepared by pulsed laser deposition (PLD) and we explore ways to improve the performance of these devices. PLD seems to be a very efficient and suitable technique for producing adherent and uniform thin films. Time-resolved mass spectrometric investigations definitively suggest that the deposition of high-purity metallic thin films

  13. Cool Cast Facts

    MedlinePLUS

    ... Get Placed? First, the doctor or cast technician — tech for short (or another person who is trained ... some water on it. The doctor or cast tech wraps the plaster or fiberglass around the soft ...

  14. Yield Improvement in Steel Casting (Yield II)

    SciTech Connect

    Richard A. Hardin; Christoph Beckermann; Tim Hays

    2002-02-18

    This report presents work conducted on the following main projects tasks undertaken in the Yield Improvement in Steel Casting research program: Improvement of Conventional Feeding and Risering Methods, Use of Unconventional Yield Improvement Techniques, and Case Studies in Yield Improvement. Casting trials were conducted and then simulated using the precise casting conditions as recorded by the participating SFSA foundries. These results present a statistically meaningful set of experimental data on soundness versus feeding length. Comparisons between these casting trials and casting trials performed more than forty years ago by Pellini and the SFSA are quite good and appear reasonable. Comparisons between the current SFSA feeding rules and feeding rules based on the minimum Niyama criterion reveal that the Niyama-based rules are generally less conservative. The niyama-based rules also agree better with both the trials presented here, and the casting trails performed by Pellini an d the SFSA years ago. Furthermore, the use of the Niyama criterion to predict centerline shrinkage for horizontally fed plate sections has a theoretical basis according to the casting literature reviewed here. These results strongly support the use of improved feeding rules for horizontal plate sections based on the Niyama criterion, which can be tailored to the casting conditions for a given alloy and to a desired level of soundness. The reliability and repeatability of ASTM shrinkage x-ray ratings was investigated in a statistical study performed on 128 x-rays, each of which were rated seven different times. A manual ''Feeding and Risering Guidelines for Steel Castings' is given in this final report. Results of casting trials performed to test unconventional techniques for improving casting yield are presented. These use a stacked arrangement of castings and riser pressurization to increase the casting yield. Riser pressurization was demonstrated to feed a casting up to four time s the distance of a non-pressurized riser, and can increase casting yield by decreasing the required number of risers. All case studies for this projects were completed and compiled into an SFSA Technical Report that is submitted part of this Final Report

  15. Casting Characteristics of Aluminum Die Casting Alloys

    Microsoft Academic Search

    Makhlouf M. Makhlouf; Diran Apelian

    2002-01-01

    The research program investigates the casting characteristics of selected aluminum die casting alloys. Specifically, the alloys' tendencies towards die soldering and sludge formation, and the alloys' fluidity and machinability are evaluated. It was found that: When the Fe and Mn contents of the alloy are low; caution has to be taken against possible die soldering. When the alloy has a

  16. LLNL casting technology

    SciTech Connect

    Shapiro, A.B.; Comfort, W.J. III [eds.

    1994-01-01

    Competition to produce cast parts of higher quality, lower rejection rate, and lower cost is a fundamental factor in the global economy. To gain an edge on foreign competitors, the US casting industry must cut manufacturing costs and reduce the time from design to market. Casting research and development (R&D) are the key to increasing US compentiveness in the casting arena. Lawrence Livermore National Laboratory (LLNL) is the home of a wide range of R&D projects that push the boundaries of state-of-the art casting. LLNL casting expertise and technology include: casting modeling research and development, including numerical simulation of fluid flow, heat transfer, reaction/solidification kinetics, and part distortion with residual stresses; special facilities to cast toxic material; extensive experience casting metals and nonmetals; advanced measurement and instrumentation systems. Department of Energy (DOE) funding provides the leverage for LLNL to collaborate with industrial partners to share this advanced casting expertise and technology. At the same time, collaboration with industrial partners provides LLNL technologists with broader insights into casting industry issues, casting process data, and the collective, experience of industry experts. Casting R&D is also an excellent example of dual-use technology; it is the cornerstone for increasing US industrial competitiveness and minimizing waste nuclear material in weapon component production. Annual funding for casting projects at LLNL is $10M, which represents 1% of the total LLNL budget. Metal casting accounts for about 80% of the funding. Funding is nearly equally divided between development directed toward US industrial competitiveness and weapon component casting.

  17. Growth of hierarchical based ZnO micro\\/nanostructured films and their tunable wettability behavior

    Microsoft Academic Search

    P. Suresh Kumar; A. Dhayal Raj; D. Mangalaraj; D. Nataraj; N. Ponpandian; Lin Li; G. Chabrol

    2011-01-01

    Hierarchical zinc oxide (ZnO) micro\\/nanostructured thin films were grown onto as-prepared and different annealed ZnO seed layer films by a simple two step chemical process. A cost effective successive ionic layer adsorption and reaction (SILAR) method was employed to grow the seed layer films at optimal temperature (80°C) and secondly, different hierarchical based ZnO structured thin films were deposited over

  18. Slip Casting of ?-Sialon/AlN/BN Powder Carbothermally Prepared by Boron-rich Slag-based Mixture

    NASA Astrophysics Data System (ADS)

    Jun-bin, Wu; Xiang-xin, Xue; Tao, Jiang; Qing, Zhang

    2011-10-01

    With boron-rich slag, silica fume, bauxite chalmette and carbon black as starting materials, ?-Sialon/AlN/BN powder was prepared by carbothermal reduction-nitridation. The powder was attrition milled to submicron size and suspended in water. The effects of yttrium oxide as a sintering aid, pH, and addition of deflocculant on the suspensions were study. Optimum slip casting properties, i.e. lowest viscosity values, the highest absolute zeta potential values, the smallest floc size and sediment volume were found at pH 10 for the powder. The suspensions were used to slip cast discs which were sintered in a nitrogen atmosphere at 1700°C for 2h. The strength was about 230MPa, the toughness 3.6 MPa·m1/2 and the hardness about 13.8GPa.

  19. Development of Stronger and More Reliable Cast Austenitic Stainless Steels (H-Series) Based on Scientific and Design Methodology

    SciTech Connect

    Pankiw, Roman I; Muralidharan, G. (Murali); Sikka, Vinod K.

    2006-06-30

    The goal of this project was to increase the high-temperature strength of the H-Series of cast austenitic stainless steels by 50% and the upper use temperature by 86 to 140 degrees fahrenheit (30 to 60 degrees celsius). Meeting this goal is expected to result in energy savings of 35 trillion Btu/year by 2020 and energy cost savings of approximately $230 million/year. The higher-strength H-Series cast stainless steels (HK and HP type) have applications for the production of ethylene in the chemical industry, for radiant burner tubes and transfer rolls for secondary processing of steel in the steel industry, and for many applications in the heat treating industry, including radiant burner tubes. The project was led by Duraloy Technologies, Inc., with research participation by Oak Ridge National Laboratory (ORNL) and industrial participation by a diverse group of companies.

  20. Casting and Molding

    NSDL National Science Digital Library

    Perkins School for the Blind

    2012-06-26

    This activity was designed for blind learners, but all types of learners can explore the process used to cast and mold molten metal, glass, and plastics. Using gelatin, the learner will work with a variety of molds to create castings. When the shapes are unmolded, the learner can tactually explore the casts.

  1. Development of Stronger and More Reliable Cast Austenitic Stainless Steels (H-Series) Based on Scientific Design Methodology

    Microsoft Academic Search

    G. Muralidharan; V. K. Sikka; R. I. Pankiw

    2006-01-01

    The goal of this program was to increase the high-temperature strength of the H-Series of cast austenitic stainless steels by 50% and upper use temperature by 86 to 140 F (30 to 60 C). Meeting this goal is expected to result in energy savings of 38 trillion Btu\\/year by 2020 and energy cost savings of $185 million\\/year. The higher strength

  2. An electron metallographic study of pressure die-cast commercial zinc–aluminium-based alloy ZA27

    Microsoft Academic Search

    M. DURMAN; S. MURPHY

    1997-01-01

    The microstructure of ZA27 pressure die-castings was examined by scanning and transmission electron microscopy after ageing\\u000a for 5 years at ambient temperatures. Solidification began with the formation of compact aluminium-rich ?? dendrites and tiny\\u000a rounded ?? particles, followed by the peritectic reaction whereby a zinc-rich ? phase formed around the edges of the primary\\u000a phases. The extremely high cooling rate

  3. Tribological behaviors of lanthanum-based phosphonate 3-aminopropyltriethoxysilane self-assembled films

    NASA Astrophysics Data System (ADS)

    Gu, Qinlin; Cheng, Xianhua

    2007-06-01

    Lanthanum-based thin films deposited on the phosphonate 3-aminopropyltriethoxysilane (APTES) self-assembled monolayer (SAM) were prepared on the hydroxylated glass substrate by a self-assembling process from specially formulated solution. Chemical compositions of the films and chemical state of the elements were detected by X-ray photoelectron spectrometry (XPS). The thickness of the films was determined with an ellipsometer, while the morphologies of the original and worn surfaces of the samples were analyzed by means of atomic force microscopy (AFM) and scanning electron microscopy (SEM), respectively. The tribological properties of the films sliding against GCr15 steel ball were evaluated on a UMT-2MT reciprocating friction and wear tester. As the results, the target film was obtained and reaction may have taken place between the film and the glass substrate. The tribological results show that lanthanum-based thin films are superior in reducing friction and resisting wear compared with APTES-SAM and phosphorylated APTES-SAM. SEM observation of the morphologies of worn surfaces indicates that the wear of APTES-SAM and the phosphorylated APTES-SAM is characteristic of brittle fracture and severe abrasion. Differently, slight abrasion and micro-crack dominate the wear of lanthanum-based thin films. The superior friction reduction and wear resistance of lanthanum-based thin films are attributed to the enhanced load-carrying capacity of the inorganic lanthanum particles in the lanthanum-based thin films as well as good adhesion of the films to the substrate.

  4. Effects of Fluorine and BaO on the Crystallization Behavior of Lime-Alumina-Based Mold Flux for Casting High-Al Steels

    NASA Astrophysics Data System (ADS)

    Lu, Boxun; Wang, Wanlin

    2015-04-01

    With the development of advanced high-strength steel, the slag/steel reaction problems introduced by the addition of aluminum into steel become a challenge for the continuous casting process. An investigation aims to improve the crystallization property of lime-alumina-based mold flux for casting high Al-bearing steels which was carried out through the study of effects of fluorine and BaO on the crystallization behaviors of the mold flux. The single/double hot thermocouple technique and SEM, EDS were employed in the study. The results indicated that the decrease of fluorine content would promote the crystallization behaviors in the lime-alumina-based system which is different to that in the conventional lime-silica-based system, while BaO substituted for CaO can inhibit the crystallization of the lime-alumina-based mold flux. Moreover, the crystallization behavior of mold flux under simulated thermal gradient was in well accordance with TTT results, including the crystallization process and three-layered (liquid, crystalline, glassy) distribution of mold flux.

  5. PVDF-PZT nanocomposite film based self-charging power cell.

    PubMed

    Zhang, Yan; Zhang, Yujing; Xue, Xinyu; Cui, Chunxiao; He, Bin; Nie, Yuxin; Deng, Ping; Lin Wang, Zhong

    2014-03-14

    A novel PVDF-PZT nanocomposite film has been proposed and used as a piezoseparator in self-charging power cells (SCPCs). The structure, composed of poly(vinylidene fluoride) (PVDF) and lead zirconate titanate (PZT), provides a high piezoelectric output, because PZT in this nanocomposite film can improve the piezopotential compared to the pure PVDF film. The SCPC based on this nanocomposite film can be efficiently charged up by the mechanical deformation in the absence of an external power source. The charge capacity of the PVDF-PZT nanocomposite film based SCPC in 240 s is ?0.010 ?A h, higher than that of a pure PVDF film based SCPC (?0.004 ?A h). This is the first demonstration of using PVDF-PZT nanocomposite film as a piezoseparator for SCPC, and is an important step for the practical applications of SCPC for harvesting and storing mechanical energy. PMID:24531887

  6. Quantitative study of bacterial colonization of dental casts

    Microsoft Academic Search

    Donald L. Mitchell; Nadjmeh M. Hariri; Manville G. Duncanson; Nancy L. Jacobsen; Roderick E. McCallum

    1997-01-01

    Statement of problem. Contamination of dental casts can occur if the record bases are improperly disinfected or inadvertently not disinfected during fabrication of a prosthesis. It is essential to develop an effective means of disinfecting dental casts from professional, medical, and legal points of view.Purpose. This study determined whether: (1) saliva contamination on the surface of the dental cast contributed

  7. Beam casting implicit surfaces on the GPU with interval arithmetic

    E-print Network

    Beam casting implicit surfaces on the GPU with interval arithmetic Francisco Ganacim, Luiz Henrique, Brazil Abstract--We present a GPU-based beam-casting method for rendering implicit surfaces in real time. INTRODUCTION Rendering surfaces with ray casting is perhaps the clearest example of a potentially

  8. A System for Digital Reconstruction of Gypsum Dental Casts

    Microsoft Academic Search

    A. Ardeshir Goshtasby; S. Nambula; Waldemar G. deRijk; Stephen D. Campbell

    1997-01-01

    A range scanner is developed that can scan a gypsum dental cast and reconstruct the cast digitally for display and storage purposes. The scanner is based on subtractive light and computes the range values using optical triangulation. A fiducial marker is introduced that, when attached to a dental cast at the time of image acquisition, makes it possible to integrate

  9. Low cycle fatigue life of two nickel-base casting alloys in a hydrogen environment. [for high-pressure oxidizer turbopump turbine nozzles

    NASA Technical Reports Server (NTRS)

    Cooper, R. A.

    1976-01-01

    Samples of two nickel-base casting alloys, Mar-M-246 (a Martin Company alloy) and 713LC (a low-carbon modification of the alloy 713C developed by International Nickel Company) were tested as candidate materials for the high-pressure fuel and high-pressure oxidizer turbopump turbine nozzles. The samples were subjected to tensile tests and to low cycle fatigue tests in high-pressure hydrogen to study the influence of the hydrogen environment. The Mar-M-246 material was found to have a three times higher cyclic life in hydrogen than the 713LC alloy, and was selected as the nozzle material.

  10. Magnesium-lithium casting alloys

    NASA Technical Reports Server (NTRS)

    Latenko, V. P.; Silchenko, T. V.; Tikhonov, V. A.; Maltsev, V. P.; Korablin, V. P.

    1974-01-01

    The strength properties of magnesium-lithium alloys at room, low, and high temperatures are investigated. It is found that the alloys may have practical application at ambient temperatures up to 100 C, that negative temperatures have a favorable influence on the alloy strength, and that cyclic temperature variations have practically no effect on the strength characteristics. The influence of chemical coatings on corrosion resistance of the MgLi alloys is examined. Several facilities based on pressure casting machines, low-pressure casting machines, and magnetodynamic pumps were designed for producing MgLi alloy castings. Results were obtained for MgLi alloys reinforced with fibers having a volumetric content of 15%.

  11. Ion permeability of polydopamine films revealed using a Prussian blue-based electrochemical method.

    PubMed

    Gao, Bowen; Su, Lei; Tong, Ying; Guan, Miao; Zhang, Xueji

    2014-11-01

    Polydopamine (PDA) is fast becoming a popular surface modification technique. Detailed understanding of the ion permeability properties of PDA films will improve their applications. Herein, we report for the first time the thickness-independent ion permeability of PDA films using a Prussian blue (PB)-based electrochemical method. In this method, PDA films are deposited via ammonium persulfate-induced dopamine polymerization onto a PB electrode. The ion permeability of the PDA films can thus be detected by observing the changes in electrochemical behaviors of the PB coated by PDA films. On the basis of this method, it was unexpectedly found that the PDA films with thickness greater than 45 nm (e.g., ~60 and ~113 nm) can exhibit pH-switchable but thickness-insensitive permeability to monovalent cations such as potassium and sodium ions. These observations clearly indicate the presence of a continuous network of interconnected intermolecular voids within PDA films, regardless of film thickness. PMID:25317484

  12. Gating of Permanent Molds for Aluminum Casting

    SciTech Connect

    David Schwam; John F. Wallace; Tom Engle; Qingming Chang

    2004-01-01

    This report summarizes a two-year project, DE-FC07-011D13983 that concerns the gating of aluminum castings in permanent molds. The main goal of the project is to improve the quality of aluminum castings produced in permanent molds. The approach taken was to determine how the vertical type gating systems used for permanent mold castings can be designed to fill the mold cavity with a minimum of damage to the quality of the resulting casting. It is evident that somewhat different systems are preferred for different shapes and sizes of aluminum castings. The main problems caused by improper gating are entrained aluminum oxide films and entrapped gas. The project highlights the characteristic features of gating systems used in permanent mold aluminum foundries and recommends gating procedures designed to avoid common defects. The study also provides direct evidence on the filling pattern and heat flow behavior in permanent mold castings. Equipment and procedure for real time X-Ray radiography of molten aluminum flow into permanent molds have been developed. Other studies have been conducted using water flow and behavior of liquid aluminum in sand mold using real time photography. This investigation utilizes graphite molds transparent to X-Rays making it possible to observe the flow pattern through a number of vertically oriented grating systems. These have included systems that are choked at the base of a rounded vertical sprue and vertical gating systems with a variety of different ingates into the bottom of a mold cavity. These systems have also been changed to include gating systems with vertical and horizontal gate configurations. Several conclusions can be derived from this study. A sprue-well, as designed in these experiments, does not eliminate the vena contracta. Because of the swirling at the sprue-base, the circulating metal begins to push the entering metal stream toward the open runner mitigating the intended effect of the sprue-well. Improved designs of sprue-wells should be evaluated. In order for a runner extension to operate efficiently, it must have a small squared cross-section. If it is tapered, the first metal to enter the first metal to enter the system is not effectively trapped. If the cross section is large, there is less turbulence when the aluminum enters the mold cavity in comparison to the smaller cross sectioned, squared runner. However, a large runner reduces yield. In bottom-feeding gating systems, a filter can significantly improve the filling of the casting. The filter helps to slow the metal flow rate enough to reduce jetting into the mold cavity. In top feeding gating systems, a filter can initially slow the metal flow rate, but because the metal drops after passing the filter, high velocities are achieved during free fall when a filter is in place. Side feeding gating systems provide less turbulent flow into the mold cavity. The flow is comparable to a bottom-feeding gating system with a filter. Using properly designed side-gating system instead of a bottom-feeding system with a filter can potentially save the cost of the filter. Rough coatings promote better fill than smooth coatings. This conclusion seems at first counter intuitive. One tends to assume a rough coating creates more friction resistance to the flow of molten metal. In actuality the molten aluminum stream flows inside an oxide film envelope. When this film rests on top of the ridges of a rough coating the microscopic air pockets between the coating and the oxide film provide more thermal insulation than in a smooth coating. This insulation promotes longer feeding distances in the mold as demonstrated in the experiments. Much of this work is applicable to vertically parted sand molds as well, although the heat transfer conditions do vary from a metal mold generally used in permanent molding of aluminum. The flow measurements were conducted using graphite molds and real time X-Ray radiography recorded at a rate of 30 images per second through those molds. The facilities at Arrow Aluminum Foundry were used in the study. The resu

  13. A novel humidity sensor based on alumina nanowire films

    NASA Astrophysics Data System (ADS)

    Feng, Zhe-sheng; Chen, Xin-Jie; Chen, Jin-ju; Hu, Jing

    2012-06-01

    Alumina nanowire (ANW) films were prepared by etching porous anodic aluminium oxide (AAO), and then humidity sensors with coplanar interdigitated electrodes based on ANWs were fabricated. The ANWs not only present tremendous surface area for water molecule adsorption but also provide efficient sites for attracting water molecules at low relative humidity (RH) levels. The sensors based on the particular morphology of ANWs with large open voids show high sensitivity and small hysteresis, and have fast response and recovery time to humidity. The capacitance rises slowly at a lower RH and increases rapidly after 70% RH, which is associated with the humidity mechanism of chemisorption at lower RH and physisorption at higher RH levels. The impendence analysis suggests that the ANWs are the main factor for sensing humidity, and AAO also contributes to humidity sensing. This study demonstrates that ANWs have promising applications in humidity monitoring.

  14. Design and evaluation of polysaccharide-based transdermal films for the controlled delivery of nifedipine.

    PubMed

    Bekta?, Ay?egül; Cevher, Erdal; Güngör, Sevgi; Ozsoy, Y?ld?z

    2014-01-01

    It was aimed to develop the matrix type polysaccharide-based transdermal films of nifedipine (NFD) to provide its long term plasma concentration. The mechanical tests were carried out on gel formulations which were utilised in the fabrication of transdermal films to determine the type of polymer (pectin, sodium alginate) and plasticizer (propylene glycol, glycerine) as well as their concentrations. The mechanical strength, elasticity, bioadhesiveness and the drug release characteristics of optimised films containing NFD were evaluated. Permeation of NFD from the films with/without adding an enhancer (nerolidol) was followed through excised rat skin using Franz diffusion cells. Results showed that the gels composed of either pectin or sodium alginate were appropriate for the fabrication of transdermal films of NFD, and the addition of propylene glycol improved mechanical strength, flexibility, and bioadhesiveness of the films. Permeation data showed that nerolidol was an effective permeation enhancer for the polysaccharide-based transdermal films of NFD. PMID:24492584

  15. Mechanical, water vapor barrier and thermal properties of gelatin based edible films

    Microsoft Academic Search

    P. J. A. Sobral; F. C. Menegalli; M. D. Hubinger; M. A. Roques

    2001-01-01

    Edible films are thin materials based on a biopolymer. The objectives of this work were to determine the water vapor permeability and the mechanical and thermal properties of edible films based on bovine hide and pigskin gelatins. These films were prepared with 1g of gelatin\\/100ml of water; 15–65g sorbitol\\/100g gelatin; and at natural pH. The samples were conditioned at 58%

  16. Investigation of quaternary Al-based quasicrystal thin films for corrosion protection

    Microsoft Academic Search

    V. N. Balbyshev; D. J. King; A. N. Khramov; L. S. Kasten; M. S. Donley

    2004-01-01

    Recent work has shown that thin film quasicrystal coatings have unique properties such as very high electrical and thermal resistivities and very low surface energy. Aluminum-based quasicrystals are insulator alloys composed of approximately 70% of aluminum. The corrosion related properties of aluminum-based quasicrystal thin film coatings have been studied on quasicrystal-coated AA-2024 substrates. The thin film deposition parameters are discussed.

  17. Lead-based titanate ferroelectric thin films fabricated by a sol–gel technique

    Microsoft Academic Search

    D. G. Wang; C. Z. Chen; J. Ma; T. H. Liu

    2008-01-01

    Because of its excellent ferroelectric properties including piezoelectricity, thermoelectricity and photoelectricity, the lead-based titanate ferroelectric thin films have been widely used in the high-tech fields such as microelectronics, optoelectronics, integrated optics and microelectro-mechanical system. As a significant technique in preparing thin films, the sol–gel method has achieved great success in preparing the lead-based titanate ferroelectric thin films. In this paper,

  18. Processing of IN-718 Lattice Block Castings

    NASA Technical Reports Server (NTRS)

    Hebsur, Mohan G.

    2002-01-01

    Recently a low cost casting method known as lattice block casting has been developed by JAM Corporation, Wilmington, Massachusetts for engineering materials such as aluminum and stainless steels that has shown to provide very high stiffness and strength with only a fraction of density of the alloy. NASA Glenn Research Center has initiated research to investigate lattice block castings of high temperature Ni-base superalloys such as the model system Inconel-718 (IN-718) for lightweight nozzle applications. Although difficulties were encountered throughout the manufacturing process , a successful investment casting procedure was eventually developed. Wax formulation and pattern assembly, shell mold processing, and counter gravity casting techniques were developed. Ten IN-718 lattice block castings (each measuring 15-cm wide by 30-cm long by 1.2-cm thick) have been successfully produced by Hitchiner Gas Turbine Division, Milford, New Hampshire, using their patented counter gravity casting techniques. Details of the processing and resulting microstructures are discussed in this paper. Post casting processing and evaluation of system specific mechanical properties of these specimens are in progress.

  19. Processing and characteristics of spin-cast ferroelectric Bi{sub 4}Ti{sub 3}O{sub 12} thin films

    SciTech Connect

    Buchanan, R.C.; Chu, Peir-Yung [Univ. of Cincinnati, OH (United States)

    1994-12-31

    Bi{sub 4}Ti{sub 3}O{sub 12} thin films were successfully prepared on Si(100) substrates from solution precursors by spin-coating. The precursor solution consisted of a mixture of bismuth nitrate and titanium sec-butoxide, in stoichiometric ratio, dissolved in a carboxylic acid/amine solvent system. Most organics in the precursors were removed by 350{degrees}C and crystallization occurred below 500{degrees}C. A mechanism for molecular complex formation in the mixed alkoxide/carboxylate system is proposed. Heating rate, temperature, and film thickness showed significant effects on film (001) preferred orientation and grain growth. To limit film/substrate interfacial reactions, heat treatment was carried out at or below 850{degrees}C. Measured remament polarization in fired Bi{sub 4}Ti{sub 3}O{sub 12} varied between 8-20 {mu}C/cm{sup 2} with a coercive field of 100-180 kV/cm, depending on processing temperature.

  20. Printed organic thin-film transistor-based integrated circuits

    NASA Astrophysics Data System (ADS)

    Mandal, Saumen; Noh, Yong-Young

    2015-06-01

    Organic electronics is moving ahead on its journey towards reality. However, this technology will only be possible when it is able to meet specific criteria including flexibility, transparency, disposability and low cost. Printing is one of the conventional techniques to deposit thin films from solution-based ink. It is used worldwide for visual modes of information, and it is now poised to enter into the manufacturing processes of various consumer electronics. The continuous progress made in the field of functional organic semiconductors has achieved high solubility in common solvents as well as high charge carrier mobility, which offers ample opportunity for organic-based printed integrated circuits. In this paper, we present a comprehensive review of all-printed organic thin-film transistor-based integrated circuits, mainly ring oscillators. First, the necessity of all-printed organic integrated circuits is discussed; we consider how the gap between printed electronics and real applications can be bridged. Next, various materials for printed organic integrated circuits are discussed. The features of these circuits and their suitability for electronics using different printing and coating techniques follow. Interconnection technology is equally important to make this product industrially viable; much attention in this review is placed here. For high-frequency operation, channel length should be sufficiently small; this could be achievable with a combination of surface treatment-assisted printing or laser writing. Registration is also an important issue related to printing; the printed gate should be perfectly aligned with the source and drain to minimize parasitic capacitances. All-printed organic inverters and ring oscillators are discussed here, along with their importance. Finally, future applications of all-printed organic integrated circuits are highlighted.

  1. Research on the measurement of thin film thickness based on phaseshift interferometry

    NASA Astrophysics Data System (ADS)

    Shi, Yi-lei; Su, Jun-hong; Yang, Li-hong; Xu, Jun-qi

    2009-05-01

    Only by solving the problem of accurate measurement of thin film thickness, will it be possible to solve the problem of thin film preparation. A novel measurement method of thin film thickness based on phase-shift interferometry is presented in the paper. Taking advantage of Twyman-Green interferometer, the multi-frame interferogram measured the thin film can be obtained by receiving the interference fringes of thin film by means of CCD and using digital acquisition card to collect interferogram and with the help of computer control PZT driver and modulation piezoelectric regulator to promote reference mirror uniformly-spaced movement. After the gained interferogram were disposed of phase unwrapped, 3D wavefront containing the information of thin film thickness can be obtained. According to the characteristics between the thin film thickness and the unwrapping phase, taking advantage of the overlapping 4-frame average algorithm, corresponding relationships between the quantification phase information and thin film thickness of each point has been established to realize the thin film thickness accurate measurement. The results show that this method has the advantage of non-contact, the high accuracy, not only has testified the feasibility of film thickness measurement with phase-shift interferometry, but also has further ensured research and optimization of the thin film preparation technics. The PV and RMS value of the measured thin film thickness are 0.162?m and 0.043?m respectively.

  2. Strongly correlated electron behavior in arsenic-based and thin film antimony-based filled skutterudites

    Microsoft Academic Search

    Ryan Eagle Baumbach

    2009-01-01

    Results for two categories of filled skutterudites that have previously received limited attention are presented: (1) single crystals of the As-based filled skutterudites and (2) thin films of the Sb-based filled skutterudites. We show that the compounds CeT4As 12 (T = Ru, Os) exhibit non-Fermi liquid and Kondo insulator behavior, respectively. The phenomena seen in these materials is discussed in

  3. Novel biodegradable films made from chitosan and poly(lactic acid) with antifungal properties against mycotoxinogen strains

    Microsoft Academic Search

    Fimbeau Sébastien; Grelier Stéphane; Alain Copinet; Veronique Coma

    2006-01-01

    Composite films from chitosan and poly(lactic acid) (PLA) were prepared by solution mixing and a film casting procedure. The main objectives of this study were the elaboration and the characterization of chitosan\\/PLA based bio-packaging for potential food applications and the study of antifungal activity of coatings and films on three mycotoxinogen fungal strains, Fusarium proliferatum, Fusarium moniliforme and Aspergillus ochraceus.

  4. Tungsten oxide proton conducting films for low-voltage transparent oxide-based thin-film transistors

    SciTech Connect

    Zhang, Hongliang; Wan, Qing; Wan, Changjin; Wu, Guodong; Zhu, Liqiang [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)] [Ningbo Institute of Material Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2013-02-04

    Tungsten oxide (WO{sub x}) electrolyte films deposited by reactive magnetron sputtering showed a high room temperature proton conductivity of 1.38 Multiplication-Sign 10{sup -4} S/cm with a relative humidity of 60%. Low-voltage transparent W-doped indium-zinc-oxide thin-film transistors gated by WO{sub x}-based electrolytes were self-assembled on glass substrates by one mask diffraction method. Enhancement mode operation with a large current on/off ratio of 4.7 Multiplication-Sign 10{sup 6}, a low subthreshold swing of 108 mV/decade, and a high field-effect mobility 42.6 cm{sup 2}/V s was realized. Our results demonstrated that WO{sub x}-based proton conducting films were promising gate dielectric candidates for portable low-voltage oxide-based devices.

  5. Optical properties of porous-silicon-based structures with modified nanodiamond films

    NASA Astrophysics Data System (ADS)

    Yuzova, V. A.; Korets, A. Ya.; Merkushev, F. F.; Semenova, O. V.

    2015-02-01

    We have studied the optical properties of silicon-based sandwich structures with diamond-like films deposited by electrophoresis from aqueous suspensions of modified detonation nanodiamonds. It is shown that these films can be used as antireflection and protective coatings for silicon-based solar cells.

  6. Amorphous Silicon(aSi:H) Thin Film Based Omnidirectional Control Solar Powered Vehicle

    Microsoft Academic Search

    Abdullah Moinuddin; Jony C. Sarker; Akhter Zia

    2012-01-01

    Through the paper, our goal is to drive a car with the help of thin film based solar cell. Mechanical and Electrical parts are assembled thereby. The main objective of this project is to collect maximum solar energy from the solar spectrum and use that solar energy to drive the car. Amorphous silicon based thin film solar panel has been

  7. National Metal Casting Research Institute final report. Volume 2, Die casting research

    SciTech Connect

    Jensen, D. [University of Northern Iowa, Cedar Falls, IA (United States). Dept. of Industrial Technology] [comp.

    1994-06-01

    Four subprojects were completed: development and evaluation of die coatings, accelerated die life characterization of die materials, evaluation of fluid flow and solidification modeling programs, selection and characterization of Al-based die casting alloys, and influence of die materials and coatings on die casting quality.

  8. Natural biopolymer-based nanocomposite films for packaging applications.

    PubMed

    Rhim, Jong-Whan; Ng, Perry K W

    2007-01-01

    Concerns on environmental waste problems caused by non-biodegradable petrochemical-based plastic packaging materials as well as the consumer's demand for high quality food products has caused an increasing interest in developing biodegradable packaging materials using annually renewable natural biopolymers such as polysaccharides and proteins. Inherent shortcomings of natural polymer-based packaging materials such as low mechanical properties and low water resistance can be recovered by applying a nanocomposite technology. Polymer nanocomposites, especially natural biopolymer-layered silicate nanocomposites, exhibit markedly improved packaging properties due to their nanometer size dispersion. These improvements include increased modulus and strength, decreased gas permeability, and increased water resistance. Additionally, biologically active ingredients can be added to impart the desired functional properties to the resulting packaging materials. Consequently, natural biopolymer-based nanocomposite packaging materials with bio-functional properties have a huge potential for application in the active food packaging industry. In this review, recent advances in the preparation of natural biopolymer-based films and their nanocomposites, and their potential use in packaging applications are addressed. PMID:17457725

  9. Cellulose triacetate, thin film dielectric capacitor

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (inventor); Jow, T. Richard (inventor)

    1993-01-01

    Very thin films of cellulose triacetate are cast from a solution containing a small amount of high boiling temperature, non-solvent which evaporates last and lifts the film from the casting surface. Stretched, oriented, crystallized films have high electrical breakdown properties. Metallized films less than about 2 microns in thickness form self-healing electrodes for high energy density, pulsed power capacitors. Thicker films can be utilized as a dielectric for a capacitor.

  10. Cellulose triacetate, thin film dielectric capacitor

    NASA Technical Reports Server (NTRS)

    Yen, Shiao-Ping S. (inventor); Jow, T. Richard (inventor)

    1995-01-01

    Very thin films of cellulose triacetate are cast from a solution containing a small amount of high boiling temperature, non-solvent which evaporates last and lifts the film from the casting surface. Stretched, oriented, crystallized films have high electrical breakdown properties. Metallized films less than about 2 microns in thickness form self-healing electrodes for high energy density, pulsed power capacitors. Thicker films can be utilized as a dielectric for a capacitor.

  11. The taper of cast post preparation measured using innovative image processing technique

    Microsoft Academic Search

    Khaled Q Al Hamad; Faruq A Al-Omari; Ahmad S Al Hyiasat

    2010-01-01

    BACKGROUND: No documentation in the literature about taper of cast posts. This study was conducted to measure the degree of cast posts taper, and to evaluate its suitability based on the anatomy aspects of the common candidate teeth for post reconstruction. METHODS: Working casts for cast posts, prepared using Gates Glidden drills, were collected. Impressions of post spaces were made

  12. High Efficiency Thin Film CdTe and a-Si Based Solar Cells Annual Technical Report for the Period

    E-print Network

    Deng, Xunming

    High Efficiency Thin Film CdTe and a-Si Based Solar Cells Annual Technical Report for the Period This report covers the second year of this subcontract for research on high efficiency CdTe-based thin-film solar cells and on high efficiency a-Si-based thin-film solar cells. The effort on CdTe- based materials

  13. Characterization of antioxidant methylcellulose film incorporated with ?-tocopherol nanocapsules.

    PubMed

    Noronha, Carolina Montanheiro; de Carvalho, Sabrina Matos; Lino, Renata Calegari; Barreto, Pedro Luiz Manique

    2014-09-15

    Biodegradable and antioxidant films based on methylcellulose (MC) and ?-tocopherol nanocapsule suspension (NCs) were developed. MC and NCs films were prepared by a casting method in three different proportions. The mechanical, wettability, colour, light transmission, antioxidant and release characteristics of the films were studied. The addition of NCs to MC films decreased the tensile strength (TS) and the elastic modulus (EM) (p<0.05) but increased the percentage elongation at break (%E) and thickness (p<0.05). NCs films showed a higher hydrophobicity when compared to that of film control. Lightness and yellowish color were intensified in the NCs films which, in their turn, demonstrated high antioxidant activity and excellent barrier properties against UV and visible light. A burst and prolonged release of ?-tocopherol to food simulant was also reported. PMID:24767092

  14. Investigation of thin films of organic-based magnets grown by physical vapor deposition

    NASA Astrophysics Data System (ADS)

    Kao, C. Y.; Li, B.; Lu, Y.; Yoo, J.-W.; Epstein, A. J.

    2014-10-01

    Thin films of organic-based magnet, V[TCNE]x (TCNE: tetracyanoethylene), were deposited by physical vapor deposition (PVD) based reactive evaporation. The growth conditions were studied in detail. A saturated composition of V[TCNE]˜1.9 was determined by optimizing the growth condition. Two sets of films with different V to TCNE ratios were characterized. Both films were magnetic ordered up to 400 K and held coercive field of 60 Oe at room temperature. With the presence of excess vanadium within the film, the increase of defects created by PVD results in significant change in electronic property.

  15. Investigation of thin films of organic-based magnets grown by physical vapor deposition

    SciTech Connect

    Kao, C. Y.; Lu, Y. [Department of Chemistry and Biochemistry, Ohio State University, Columbus, Ohio 43210 (United States); Li, B. [MEMSIC, One Tech Drive, Suite 325, Andover, Massachusetts 01810 (United States); Yoo, J.-W. [School of Materials Science and Engineering-Low dimensional Carbon Materials Center, Ulsan National Institute of Science and Technology, Ulsan 688-798 (Korea, Republic of); Epstein, A. J. [Department of Chemistry and Biochemistry, Ohio State University, Columbus, Ohio 43210 (United States); Department of Physics, Ohio State University, Columbus, Ohio 43210 (United States)

    2014-10-06

    Thin films of organic-based magnet, V[TCNE]{sub x} (TCNE: tetracyanoethylene), were deposited by physical vapor deposition (PVD) based reactive evaporation. The growth conditions were studied in detail. A saturated composition of V[TCNE]{sub ?1.9} was determined by optimizing the growth condition. Two sets of films with different V to TCNE ratios were characterized. Both films were magnetic ordered up to 400?K and held coercive field of 60?Oe at room temperature. With the presence of excess vanadium within the film, the increase of defects created by PVD results in significant change in electronic property.

  16. A microwave phase shifter based on a planar ferrite-ferroelectric thin-film structure

    NASA Astrophysics Data System (ADS)

    Nikitin, A. A.; Ustinov, A. B.; Semenov, A. A.; Kalinikos, B. A.

    2014-04-01

    Microwave phase shifters employing slot transmission lines based on thin ferroelectric films of barium strontium titanate and thin single-crystalline films of yttrium iron garnet ferrite have been experimentally studied for the first time. The phase shifters admit double electronic control based upon the phenomenon of hybridization of the electromagnetic wave propagating in a slot delay line on the ferroelectric film and the spin wave propagating in the ferrite film. At a bias voltage of 150 V applied to electrodes of the slot lines with 50- and 150-?m-wide slots, the phase shift amounted to 53° and 26°, respectively.

  17. Nanostructured biocomposite films of high toughness based on native chitin nanofibers and chitosan

    PubMed Central

    Mushi, Ngesa E.; Utsel, Simon; Berglund, Lars A.

    2014-01-01

    Chitosan is widely used in films for packaging applications. Chitosan reinforcement by stiff particles or fibers is usually obtained at the expense of lowered ductility and toughness. Here, chitosan film reinforcement by a new type of native chitin nanofibers is reported. Films are prepared by casting from colloidal suspensions of chitin in dissolved chitosan. The nanocomposite films are chitin nanofiber networks in chitosan matrix. Characterization is carried out by dynamic light scattering, quartz crystal microbalance, field emission scanning electron microscopy, tensile tests and dynamic mechanical analysis. The polymer matrix nanocomposites were produced in volume fractions of 8, 22, and 56% chitin nanofibers. Favorable chitin-chitosan synergy for colloidal dispersion is demonstrated. Also, lowered moisture sorption is observed for the composites, probably due to the favorable chitin-chitosan interface. The highest toughness (area under stress-strain curve) was observed at 8 vol% chitin content. The toughening mechanisms and the need for well-dispersed chitin nanofibers is discussed. Finally, desired structural characteristics of ductile chitin biocomposites are discussed. PMID:25478558

  18. INTERIOR VIEW WITH LARGE PIPE CASTING MACHINE CASTING A 48' ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW WITH LARGE PIPE CASTING MACHINE CASTING A 48' PIPE. - United States Pipe & Foundry Company Plant, Pipe Casting & Testing Area, 2023 St. Louis Avenue at I-20/59, Bessemer, Jefferson County, AL

  19. INTERIOR VIEW WITH PIPE CASTING MACHINE CASTING A 24' PIPE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW WITH PIPE CASTING MACHINE CASTING A 24' PIPE AND OPERATOR JOHNNY NIXON. - United States Pipe & Foundry Company Plant, Pipe Casting & Testing Area, 2023 St. Louis Avenue at I-20/59, Bessemer, Jefferson County, AL

  20. Spin-Cast and Patterned Organophosphonate Self-Assembled Monolayer Dielectrics on Metal-Oxide-Activated Si

    SciTech Connect

    O Acton; D Hutchins; L Arnadottir; T Weidner; N Cernetic; G Ting; T Kim; D Castner; H Ma; A Jen

    2011-12-31

    An efficient process is developed for modifying Si with self-assembled monolayers (SAMs) through in situ metal oxide surface activation and microcontact printing or spin-coating of phosphonic-acid-based molecules. The utility of this process is demonstrated by fabricating self-organized and solution-processed low-voltage organic thin-film transistors enabled by patterned and spin-cast phosphonate SAM/metal oxide hybrid dielectrics.

  1. Comparative study on micromorphology and humidity sensitive properties of thin-film and thick-film humidity sensors based on semiconducting MnWO 4

    Microsoft Academic Search

    Wenmin Qu; Wojtek Wlodarski; Jörg-Uwe Meyer

    2000-01-01

    Based on our experience of developing thick-film MnWO4 humidity sensors, a thin-film humidity sensor with nano-sized MnWO4 grains has been fabricated using the sol–gel technique. The thin-film sensor shows smaller humidity sensitivity than that compared to a thick-film sensor. However, it exhibits a fast response to humidity change and also has a very low temperature coefficient within the temperature range

  2. Hickey, W8206, all casts Hickey, W8206, all casts, page 1

    E-print Network

    Hickey, Barbara

    Hickey, W8206, all casts Hickey, W8206, all casts, page 1 #12;Hickey, W8206, all casts Hickey, W8206, all casts, page 2 #12;Hickey, W8206, all casts Hickey, W8206, all casts, page 3 #12;Hickey, W8206, all casts Hickey, W8206, all casts, page 4 #12;Hickey, W8206, all casts Hickey, W8206, all casts, page

  3. Electron transport in Mo_2N Nanoparticle-Based Films.

    NASA Astrophysics Data System (ADS)

    Sumanasekera, Gamini U.; Allen, Jan L.; Eklund, Peter C.

    1997-03-01

    The resistance ?(T) of Mo_2N nanoparticle-based films in the temperature range 77 < T < 500 K has been studied as a function of particle surface treatment. The nanoparticles were synthesized via CO2 laser pyrolysis of Mo(CO)6 and NH3 , colloidally suspended in acetonitrile, and then injected under flowing N2 into a narrow groove cut into a silicon substrate with pre-evaporated gold contacts in the four probe configuration. The resistivity of the resulting nanoparticle film coating the groove is measured in flowing, high-purity Ar. Three temperature regimes in ?(T) are found. For T<350 K, an activation energy E_a ~ 0.2 eV is observed which is a factor of 2 lower than the value observed at T > 350 K, where E_a ~ 0.4 - 0.5 eV. In between these two activated regimes, only a narrow range of metallic behavior is observed, although bulk Mo_2N is a metal over the entire range of interest. These data, and those obtained on similar samples after various chemical treatments of the nanoparticle surface, will be presented and discussed in terms of charge transport models in granular materials. For example, the high-T activation energy appears consistent with the energy required to separate charge on adjacent nanoparticles and yields a value for the mean particle dia ~ 3 nm, in agreement with TEM images. This work was supported by the U.S. Department of Energy (DEFC22-93PC93053)

  4. Manganese perovskites: Thick-film based position sensors fabrication

    Microsoft Academic Search

    Ll. Balcells; R. Enrich; J. Mora; A. Calleja; J. Fontcuberta; X. Obradors

    1996-01-01

    In this letter we report on the growth of thick films of magnetoresistive La2\\/3Sr1\\/3MnO3 films using a spray printing technique. The as-prepared films display a room-temperature magnetoresistance of 0.0012%\\/Oe in the 1 kOe field region. We will show that this field sensitivity is high enough to fabricate devices which, operated under a bias magnetic field, can be used as a

  5. Measurement of residual stress in DLC films prepared by plasma-based ion implantation and deposition

    Microsoft Academic Search

    Yoshihiro Oka; Michiharu Kirinuki; Yoshimi Nishimura; Kingo Azuma; Etsuo Fujiwara; Mitsuyasu Yatsuzuka

    2004-01-01

    A hybrid process of plasma-based ion implantation and deposition (PBIID) was used to achieve relaxation of compressive residual stress in diamond-like carbon (DLC) films. The residual stress in each film was determined from the curvature of quartz glass plate using Stoney's equation. The compressive residual stress in the DLC film prepared using acetylene gas was about 0.46 GPa without the

  6. Solution-processed flexible transparent conductors based on carbon nanotubes and silver grid hybrid films.

    PubMed

    Wang, Jing; Zhang, Jintao; Sundramoorthy, Ashok Kumar; Chen, Peng; Chan-Park, Mary B

    2014-05-01

    In a simple, cost-effective, and solution-based process, a thin-film of single-walled carbon nanotubes is hybridized on a PET film which has been patterned with solution self-assembled Ag nanoparticles. Such a flexible and transparent electrode exhibits a sheet resistance down to ?5.8 ? sq(-1) at ?83.7% optical transmittance. The hybrid films are stable under ambient conditions and offer excellent bendability. PMID:24675812

  7. Development of FeCo-based thin films for gigahertz applications

    Microsoft Academic Search

    Eunji Yu; Jong Sik Shim; Inyoung Kim; Jongryoul Kim; Suk Hee Han; Hi Jung Kim; Ki Hyeon Kim; Masahiro Yamaguchi

    2005-01-01

    For improving high-frequency characteristics and soft magnetic properties of (Fe7Co3)B-based thin films, the effects of Ni addition and an oblique deposition method on the microstructures have been examined. The Ni addition to (Fe7Co3)B films was found to enhance B segregation on grain boundaries, which resulted in the formation of a well-defined columnar structure and the increase of film resistivity. Utilizing

  8. Optical and electric properties of composite films based on alicyclic polyimide and polyaniline

    NASA Astrophysics Data System (ADS)

    Zhubanov, B. A.; Matnishyan, A. A.; Kravtsova, V. D.; Umerzakova, M. B.; Iskakov, R. M.; Prikhod'ko, O. Yu.; Alpysbaeva, B. E.

    2015-04-01

    Composite films based on alicyclic polyimide with nanosized polyaniline are studied. It is shown that the new film material has a high transmission in the visible and UV spectral regions. Hybrid films that include up to 12 wt % of polyaniline in the polyimide matrix, are stable upon heating in air up to 360-370°C, and have electric conductivity of 5.0 × 10-2 ?-1cm-1 are obtained by in situ polymerization of aniline.

  9. A Simple Model of the Mold Boundary Condition in Direct-Chill (DC) Casting of Aluminum Alloys

    NASA Astrophysics Data System (ADS)

    Baserinia, Amir R.; Ng, H.; Weckman, D. C.; Wells, M. A.; Barker, S.; Gallerneault, M.

    2012-08-01

    An accurate thermofluids model of aluminum direct-chill (DC) casting must solve the heat-transfer equations in the ingot with realistic external boundary conditions. These boundary conditions are typically separated into two zones: primary cooling, which occurs inside the water-cooled mold, and secondary cooling, where a film of water contacts the ingot surface directly. Here, a simple model for the primary cooling boundary condition of the steady-state DC casting process was developed. First, the water-cooled mold was modeled using a commercial computational fluid dynamics (CFD) package, and its effective heat-transfer coefficient was determined. To predict the air-gap formation between the ingot and mold and to predict its effect on the primary cooling, a simple density-based shrinkage model of the solidifying shell was developed and compared with a more complex three-dimensional (3-D) thermoelastic model. DC casting simulations using these two models were performed for AA3003 and AA4045 aluminum alloys at two different casting speeds. A series of experiments was also performed using a laboratory-scale rectangular DC caster to measure the thermal history and sump shape of the DC cast ingots. Comparisons between the simulations and experimental results suggested that both models provide good agreement for the liquid sump profiles and the temperature distributions within the ingot. The density-based shrinkage model, however, is significantly easier to implement in a CFD code and is more computationally efficient.

  10. A study of optical and electronic properties of organic thin film transistors based on naphthalenetetracarboxylic diimide derivatives

    Microsoft Academic Search

    Dongxing Yang

    2006-01-01

    The optical properties of spin cast thin films of N,N'-bis(3-phenoxy-3-phenoxy-phenoxy)-1,4,5,8-naphthalene-tetracarboxylic diimide (NDA-n2) and N,N'-bis(3-phenoxy-phenoxy)-1,4,5,8-naphthalene-tetracarboxylic diimide (NDA-n1) were investigated using spectroscopic ellipsometry (SE) complimented by optical absorption spectroscopy in the visible-near UV optical range and atomic force microscopy (AFM) for surface roughness. A combination of Tauc-Lorentzian and Gaussian oscillators model was used to fit the measurements obtained from SE. Film roughness

  11. Multielectrocatalysis by layer-by-layer films based on pararosaniline and vanadium-substituted phosphomolybdate.

    PubMed

    Fernandes, Diana M; Teixeira, Alexandra; Freire, Cristina

    2015-02-10

    Hybrid multilayer films based on the two molecular species pararosaniline (PR) and Keggin-type polyoxometalate K5[PMo11VO40)] (PMo11V) were prepared on different substrates using the electrostatic layer-by-layer (LbL) self-assembly method. The film buildup, monitored by electronic spectroscopy, showed a regular stepwise growth, and X-ray photoelectron spectroscopy data confirmed the presence of both molecular components within the LbL films. Scanning electron microscopy images revealed a completely covered surface with a nonuniform distribution of film components, and atomic force microscopy images confirmed a rough surface. The film electrochemical responses and permeability were studied by cyclic voltammetry. Films revealed three Mo-based redox processes (Mo(VI) ? Mo(V)) and one V-based redox process (V(V) ? V(IV)) in the potential range between 0.8 and -0.4 V vs Ag/AgCl. Studies with the redox probes [Fe(CN)6](3-/4-) and [Ru(NH3)6](3+/2+) showed that the films maintain the permeability even after six bilayers. Furthermore, the {PR/PMo11V}n multilayer films exhibit excellent Mo-based electrocatalytic activity toward reduction of iodate and V-based electrocatalytic activity toward ascorbic acid oxidation, thus acting as a versatile multielectrocatalyst. PMID:25603457

  12. Computer cast blast modelling

    Microsoft Academic Search

    S. Chung; M. McGill; D. S. Preece

    1994-01-01

    Cast blasting can be designed to utilize explosive energy effectively and economically for coal mining operations to remove overburden material. The more overburden removed by explosives, the less blasted material there is left to be transported with mechanical equipment, such as draglines and trucks. In order to optimize the percentage of rock that is cast, a higher powder factor than

  13. The influence of high thermal gradient casting, hot isostatic pressing and alternate heat treatment on the structure and properties of a single crystal nickel base superalloy

    NASA Technical Reports Server (NTRS)

    Fritzemeier, L. G.

    1988-01-01

    A development program has been conducted to improve the cyclic properties of the PWA 1480 single-crystal superalloy by reducing or entirely eliminating casting porosity at fatigue-initiation sites, through the use of improved casting process parameters and HIPing; potential mechanical property improvements in a high-pressure hydrogen environment were also sought in alternatives to the standard coating and heat-treatment cycle. High thermal gradient casting was found to yield a reduction in overall casting porosity density and pore sizes. The most dramatic mechanical property improvement resulted from HIPing.

  14. Advanced electrochromic devices based on WO 3 thin films

    Microsoft Academic Search

    S Papaefthimiou; G Leftheriotis; P Yianoulis

    2001-01-01

    We present work on the development of advanced materials suitable for use as electrochromic thin films (EC), ion storage layers and transparent conductors (TC) in electrochromic devices. These thin film layers were prepared in our laboratory by thermal evaporation and electron gun deposition. They were incorporated into electrochromic devices, which were subsequently characterized by optical and electrochemical techniques such as

  15. Neutron radiography inspection of investment castings.

    PubMed

    Richards, W J; Barrett, J R; Springgate, M E; Shields, K C

    2004-10-01

    Investment casting, also known as the lost wax process, is a manufacturing method employed to produce near net shape metal articles. Traditionally, investment casting has been used to produce structural titanium castings for aero-engine applications with wall thickness less than 1 in (2.54 cm). Recently, airframe manufacturers have been exploring the use of titanium investment casting to replace components traditionally produced from forgings. Use of titanium investment castings for these applications reduces weight, cost, lead time, and part count. Recently, the investment casting process has been selected to produce fracture critical structural titanium airframe components. These airframe components have pushed the traditional inspection techniques to their physical limits due to cross sections on the order of 3 in (7.6 cm). To overcome these inspection limitations, a process incorporating neutron radiography (n-ray) has been developed. In this process, the facecoat of the investment casting mold material contains a cocalcined mixture of yttrium oxide and gadolinium oxide. The presence of the gadolinium oxide, allows for neutron radiographic imaging (and eventual removal and repair) of mold facecoat inclusions that remain within these thick cross sectional castings. Probability of detection (POD) studies have shown a 3 x improvement of detecting a 0.050 x 0.007 in2 (1.270 x 0.178 mm2) inclusion of this cocalcined material using n-ray techniques when compared to the POD using traditional X-ray techniques. Further, it has been shown that this n-ray compatible mold facecoat material produces titanium castings of equal metallurgical quality when compared to the traditional materials. Since investment castings can be very large and heavy, the neutron radiography facilities at the University of California, Davis McClellan Nuclear Radiation Center (UCD/MNRC) were used to develop the inspection techniques. The UCD/MNRC has very unique facilities that can handle large parts up to 39 ft (12 m) in length and 13 ft (4 m) high weighing up to 5000 lbs (2300 kg). These handling systems are robotically driven. The neutron radiographic system consists of a highly thermalized neutron beam. The neutron beam has an intensity of 5.6 x 10(6) n/cm2 s, with a L/D = 200 at a power of 2 MW. A divergent beam collimator is used which provides a beam of approximately 22 in (56 cm) in diameter at the film plane. A vacuum cassette with a gadolinium vapor deposited screen is used to collect the image. Exposure times can be as short as 3 min, or up to 30 min. PMID:15246417

  16. Antimicrobial and in vitro wound healing properties of novel clay based bionanocomposite films.

    PubMed

    Mishra, R K; Ramasamy, K; Lim, S M; Ismail, M F; Majeed, A B A

    2014-08-01

    The present study investigates the development of methyl cellulose (MC)-sodium alginate (SA)-montmorillonite (MMT) clay based bionanocomposite films with interesting wound healing properties. The differential scanning calorimetry analysis of the composite films revealed presence of single glass transition temperature (Tg) confirming the miscible nature of the ternary blended films. The increase in MMT ratio in the composite films reduced the mobility of biopolymer chains (MC/SA) which increased the Tg of the film. Thermogravimetric analysis showed that dispersion of clay (MMT) at nano level significantly delayed the weight loss that correlated with higher thermal stability of the composite films. It was observed that the developed films were able to exhibit antimicrobial activity against four typical pathogenic bacteria found in the presence of wound. The developed films were able to significantly inhibit (10 mg/ml) the growth of Enterococcus faecium and Pseudomonas aeruginosa. In vitro scratch assay indicated potential wound closure activities of MC-2-4 bionanocomposite films at their respective highest subtoxic doses. In conclusion, these ternary bionanocomposite films were found to be promising systems for wound healing applications. PMID:24831081

  17. Electromechanical characteristics of hybrid transparent conductive films based on graphene with a silver grid

    NASA Astrophysics Data System (ADS)

    Kim, Sung Man; Kang, Seong Jun

    2014-01-01

    A systematic study of the electromechanical properties of graphene films with a silver (Ag) grid is presented for a flexible transparent electrode. Two hybrid structures of a graphene film with a Ag grid, where the silver grid is parallel or aligned at 45° to the direction of bending, were synthesized on polyethylene terephthalate (PET) substrates. The optical transmittance of the graphene/Ag grid was 90.4%, and the sheet resistance was 29.4 ?/square. The electromechanical properties of the hybrid films were investigated using an inner/outer bending test system. Compared to the film with Ag grid parallel to the direction of bending, the hybrid film with the Ag grid aligned 45° to the direction of bending showed superior electromechanical properties. Additionally, the linear resistance of the hybrid structure of a graphene film and a Ag grid was measured. The linear resistance of the hybrid film changed slightly while that of the graphene film increased considerably with increasing distance between the two metal electrodes. The results provide useful electromechanical properties for hybrid transparent conductive films based on a graphene film and a Ag grid for the development of flexible optoelectronics.

  18. Structural and optical investigation of Te-based chalcogenide thin films

    NASA Astrophysics Data System (ADS)

    Sharma, Rita; Sharma, Shaveta; Chander, Ravi; Kumar, Praveen; Thangaraj, R.; Mian, M.

    2015-05-01

    We report the structural and optical properties of thermally evaporated Bi2Te3, In2Te3 and InBiTe3 films by using X-ray diffraction, optical and Raman Spectroscopy techniques. The as-prepared thin films were found to be Semi-crystalline by X-ray diffraction. Particle Size and Strain has been calculated from XRD data. The optical constants, film thickness, refractive index and optical band gap (Eg) has been reported for In2Te3, InBiTe3 films. Raman Spectroscopy was performed to investigate the effect of Bi, In, on lattice vibration and chemical bonding in Te based chalcogenide glassy alloys.

  19. Silver nanowire-based transparent, flexible, and conductive thin film

    PubMed Central

    2011-01-01

    The fabrication of transparent, conductive, and uniform silver nanowire films using the scalable rod-coating technique is described in this study. Properties of the transparent conductive thin films are investigated, as well as the approaches to improve the performance of transparent silver nanowire electrodes. It is found that silver nanowires are oxidized during the coating process. Incubation in hydrogen chloride (HCl) vapor can eliminate oxidized surface, and consequently, reduce largely the resistivity of silver nanowire thin films. After HCl treatment, 175 ?/sq and approximately 75% transmittance are achieved. The sheet resistivity drops remarkably with the rise of the film thickness or with the decrease of transparency. The thin film electrodes also demonstrated excellent flexible stability, showing < 2% resistance change after over 100 bending cycles. PMID:21711602

  20. Effect of adhesive primers on bonding strength of heat cure denture base resin to cast titanium and cobalt-chromium alloy

    PubMed Central

    Kim, Su-Sung; Yang, Hong-So; Park, Sang-Won; Lim, Hyun-Pil

    2009-01-01

    STATEMENT OF PROBLEM The poor chemical bonding of a denture base resin to cast titanium framework often introduces adhesive failure and increases microleakage. PURPOSE This study evaluated the shear bond strengths of a heat cure denture base resin to commercially pure titanium, Ti-6Al-4V alloy and a cobalt-chromium alloy using two adhesive primers. MATERIAL AND METHODS Disks of commercially pure titanium, Ti-6Al-4V alloy and a cobalt-chromium alloy were cast. Specimens without the primer were also prepared and used as the controls. The shear bond strengths were measured on a screw-driven universal testing machine. RESULTS The primers significantly (P < .05) improved the shear bond strengths of the heat cure resin to all metals. However, the specimens primed with the Alloy primer® (MDP monomer) showed higher bond strength than those primed with the MR bond® (MAC-10 monomer) on titanium. Only adhesive failure was observed at the metal-resin interface in the non-primed specimens, while the primed specimens showed mixed failure of adhesive and cohesive failure. CONCLUSIONS The use of appropriate adhesive metal primers makes it possible not only to eliminate the need for surface preparation of the metal framework before applying the heat cure resins, but also reduce the need for retentive devices on the metal substructure. In particular, the Alloy primer®, which contains the phosphoric acid monomer, MDP, might be clinically more acceptable for bonding a heat cure resin to titanium than a MR bond®, which contains the carboxylic acid monomer, MAC-10. PMID:21165254

  1. Structural and compositional investigations of strontium sulfide based phosphors for thin film electroluminescent display applications

    Microsoft Academic Search

    Janice E. Lau

    2000-01-01

    The work presented herein focused on investigating strontium sulfide based blue phosphor materials for full color thin film electroluminescent display applications. In this respect, key findings are reported and discussed from critical scientific and technical investigations of source precursors, growth processes and resulting materials performance leading to the identification of improved pathways for higher efficiency thin film blue phosphor materials.

  2. Modification of curvature-based thin-film residual stress measurement for MEMS applications

    Microsoft Academic Search

    K-S Chen; K-S Ou

    2002-01-01

    Wafer level thin-film residual stress characterization is crucial for the structural reliability of many semiconductor and microelectromechanical systems (MEMS) devices. Because of its simplistic nature, the curvature measurement scheme is traditionally the most widely acknowledged method. Film stress is determined by converting the measured curvatures using Stoney's formula. However, this equation is based on linear beam theory and exhibits considerable

  3. The Imagery of Rhetoric: Film and Academic Writing in the Discipline-based ESL Course.

    ERIC Educational Resources Information Center

    Kasper, Loretta F.

    2000-01-01

    Describes three reading/writing lessons on the topics of linguistics, environmental science, and anthropology used in a discipline-based college-level English as a second language course to illustrate how to use film to teach academic writing skills. Discusses how students analyze a film to help articulate the content of an essay or a book. (SR)

  4. Fiber optic sensor based on surface plasmon resonance with nanoparticle films

    Microsoft Academic Search

    Anuj K. Sharma; B. D. Gupta

    2005-01-01

    This paper reports on a novel design of a fiber optic surface plasmon resonance (SPR) sensor based on nanoparticle metal film. The performance of the proposed sensor in terms of its signal-to-noise ratio (SNR) and sensitivity under different conditions related to the film with spherical gold nanoparticles embedded in a host material is theoretically analyzed. In particular, the effect of

  5. Novel electrochromic devices based on complementary nanocrystalline TiO 2 and WO 3 thin films

    Microsoft Academic Search

    Pierre Bonhôte; Eric Gogniat; Michael Grätzel; P. V Ashrit

    1999-01-01

    Electrochromic devices were elaborated based on two complementary electrodes made of a nanocrystalline metal oxide thin film deposited on conducting glass. The first electrode holds a 5 ?m thick nanocrystalline TiO2 film derivatized by a monolayer of a phosphonated triarylamine which can be rapidly oxidized by electron transfer to the conducting support followed by charge percolation inside the monolayer. The

  6. Relationship between texture and residual macro-strain in CVD diamond films based on phenomenological analysis

    Microsoft Academic Search

    Weimin Mao; Hongxi Zhu; Leng Chen; Huiping Feng

    2008-01-01

    The relationship between texture and elastic properties of chemical vapor deposition (CVD) diamond films was analyzed based on the phenomenological theory, which reveals the influence of crystalline orientation and texture on the residual macro-strain and macro-stress. The phenomenological calculations indicated that the difference in Young's modulus could be 15% in single diamond crystals and 5% in diamond films with homogeneously

  7. Fabrication of transparent and ultraviolet shielding composite films based on graphene oxide and cellulose acetate.

    PubMed

    de Moraes, Ana Carolina Mazarin; Andrade, Patricia Fernanda; de Faria, Andreia Fonseca; Simões, Mateus Batista; Salomão, Francisco Carlos Carneiro Soares; Barros, Eduardo Bedê; Gonçalves, Maria do Carmo; Alves, Oswaldo Luiz

    2015-06-01

    Graphene oxide (GO) has been considered a promising filler material for building polymeric nanocomposites because of its excellent dispersibility and high surface area. In this work, we present the fabrication and characterization of transparent and ultraviolet (UV) shielding composite films based on GO and cellulose acetate (CA). GO sheets were found to be well-dispersed throughout the CA matrix, providing smooth and homogeneous composite films. Moreover, the GO sheets were completely embedded within the CA matrix and no presence of this nanomaterial was found at the surface. Nevertheless, CAGO composite films offered an improved high energy light-shielding capacity when compared to pristine CA films. Particularly for UVC irradiation, the CAGO film containing 0.50wt% GO displayed a UV-shielding capacity of 57%, combined with 79% optical transparency under visible light. These CAGO composite films can be potentially applied as transparent UV-protective coatings for packing biomedical, pharmaceutical, and food products. PMID:25843853

  8. Thin film porous membranes based on sol-gel chemistry for catalytic sensors

    SciTech Connect

    Hughes, R.C.; Patel, S.V.; Jenkins, M.W.; Boyle, T.J.; Gardner, T.J.; Brinker, C.J.

    1998-05-01

    Nanoporous sol-gel based films are finding a wide variety of uses including gas separations and supports for heterogeneous catalysts. The films can be formed by spin or dip coating, followed by relatively low temperature annealing. The authors used several types of these films as coatings on the Pd alloy thin film sensors they had previously fabricated and studied. The sol-gel films have little effect on the sensing response to H{sub 2} alone. However, in the presence of other gases, the nanoporous film modifies the sensor behavior in several beneficial ways. (1) They have shown that the sol-gel coated sensors were only slightly poisoned by high concentrations of H{sub 2}S while uncoated sensors showed moderate to severe poisoning effects. (2) For a given partial pressure of H{sub 2}, the signal from the sensor is modified by the presence of O{sub 2} and other oxidizing gases.

  9. Electrodeposited Fe-Co films prepared from a citric-acid-based plating bath

    NASA Astrophysics Data System (ADS)

    Yanai, T.; Uto, H.; Shimokawa, T.; Nakano, M.; Fukunaga, H.; Suzuki, K.

    2013-06-01

    Electrodeposited Fe-Co films are commonly prepared in a boric-acid-based bath. In this research, we applied citric acid instead of boric acid for the plating of Fe-Co films because boron in the waste bath is restricted by environmental-protection regulations in Japan. We evaluated the effect of citric acid on the magnetic and structural properties of the films. The saturation magnetization of the Fe-Co films slightly increased while the Fe content in the Fe-Co films decreased with increasing citric acid concentration. The lowest coercivity value of 240 A/m was obtained at a citric acid concentration of 100 g/L. The plating bath with this citric acid concentration enabled us to obtain Fe-Co films with high saturation magnetizations and smooth surface morphologies.

  10. Physicochemical and antimicrobial properties of citral and quercetin incorporated kafirin-based bioactive films.

    PubMed

    Giteru, Stephen Gitonga; Coorey, Ranil; Bertolatti, Dean; Watkin, Elizabeth; Johnson, Stuart; Fang, Zhongxiang

    2015-02-01

    The aim of this study was to determine the physicochemical and antimicrobial properties of kafirin-based bioactive films incorporating the plant essential oil citral and the polyphenol quercetin. The addition of quercetin and citral both imparted a yellowish colour to the films. The tensile strength of films significantly decreased and elongation at break increased when citral was incorporated, whereas addition of quercetin did not alter these two film parameters. The rate of water vapour transmission of the films decreased with citral incorporation but the water vapour permeability was not affected by either citral or quercetin incorporation. Furthermore, incorporation of citral and quercetin significantly lowered the oxygen permeability of the films. Film made of kafirin alone had antimicrobial activity against Listeria monocytogenes, however, films incorporating citral exhibited the highest antimicrobial activity against Campylobacter jejuni, L. monocytogenes, and Pseudomonas fluorescens. These results suggest that kafirin-based films incorporating citral and quercetin have potential as bioactive packaging to improve food safety and quality. PMID:25172719

  11. Effect of Addition of Halloysite Nanoclay and SiO 2 Nanoparticles on Barrier and Mechanical Properties of Bovine Gelatin Films

    Microsoft Academic Search

    Han Ching Voon; Rajeev Bhat; Azhar Mat Easa; M. T. Liong; A. A. Karim

    Casting method was used to prepare bovine gelatin based bio-nanocomposite films with halloysite nanoclay and nano-SiO2 as the reinforcing materials. The composition included gelatin with 20% (w\\/w) of glycerol (as plasticizer) compounded with\\u000a halloysite nanoclay and nano-SiO2 (0%, 2%, 3%, 4%, 5% w\\/w), respectively. Both types of nanocomposite films showed better mechanical and water solubility than\\u000a the pristine gelatin films.

  12. Water-based preparation of highly oleophobic thin films through aggregation of nanoparticles using layer-by-layer treatment

    NASA Astrophysics Data System (ADS)

    Nishizawa, Shingo; Shiratori, Seimei

    2012-12-01

    The layer-by-layer (LBL) adsorption technique has potential for controlling the surface wettability. In this study, we controlled surface wettability between "superhydrophobic and oleophobic" and "hydrophobic and oleophilic" by LBL process on TiO2 nanoparticle with hydrophobic polymer and hydrophilic polymer. From the cast coating with LBL process on TiO2 nanoparticle, the surface showed "superhydophobic and oleophobic" when the top surface was hydrophobic polymer, on the other hand, the surface showed "hydrophobic and oleophilic" when the top surface was hydrophilic polymer. The LBL process also affected to the structure of TiO2 nanoparticle/polymer composite, and TiO2 nanoparticle were aggregated with polymers in LBL process. In the condition of the aggregated diameter of TiO2 nanoparticle/polymer composite around 10 ?m in solution, the oleohobicity of spray coated film was enhanced with its hierarchical structure (static contact angles of rapeseed oil of 150° and hexadecane of 145°) "Superhydrophobic and high oleophobic" surfaces generated from all water-based dispersions are expected for application in technologies that need to avoid organic solvents.

  13. Erosive Wear Behavior of Nickel-Based High Alloy White Cast Iron Under Mining Conditions Using Orthogonal Array

    NASA Astrophysics Data System (ADS)

    Yoganandh, J.; Natarajan, S.; Babu, S. P. Kumaresh

    2013-09-01

    Nihard Grade-4, a nickel-bearing cast iron widely used in slurry pumps and hydrodynamic components, is evaluated for its erosive wear response under mining conditions using a statistical approach. Experiments were conducted by varying the factors namely velocity, slurry concentration, angle of impingement, and pH in three levels, using L9 orthogonal array. Analysis of variance was used to rank the factors influencing erosive wear. The results indicate that velocity is the most influencing factor followed by the angle of impingement, slurry concentration, and pH. Interaction effects of velocity, slurry concentration, angle of impingement, and pH on erosion rate have been discussed. Wear morphology was also studied using SEM characterization technique. At lower angle (30°) of impingement, the erosion of material is by micro fracture and shallow ploughing with the plastic deformation of the ductile austenitic matrix. At the normal angle (90°) of impingement, the material loss from the surface is found because of deep indentation, forming protruded lips which are removed by means of repeated impact of the erodent.

  14. Perylene Diimide Based ``Nanofabric'' Thin Films for Organic Photovoltaic Cells

    NASA Astrophysics Data System (ADS)

    Carter, Austin; Park, June Hyoung; Min, Yong; Epstein, Arthur

    2011-03-01

    We report progress in using a perylene diimide (PDI) nanofabric as an effective electron accepting nanostructure for organic photovoltaics (OPV). A key challenge in OPV continues to be the recovery of electrons after charge separation due to the relatively poor mobility of C60 and related materials. A series of PDI compounds and complexes have been synthesized and used to fabricate nanofibers and thin films using solution and vacuum deposition techniques. Overlaping PDI-based nanofibers form a fast electron-transporting ``nanofabric'' that has been characterized (AFM, PL, UV-vis, etc.) and can be blended with electron donating materials. A solution-processible OPV configuration containing a nanofabric heterojunction (FHJ) of poly(3-hexylthiophene) and the PDI nanofabric was investigated. We observed a significant improvement in power-conversion efficiency due in part to expansion of the interfacial area and the presence of high mobility electron pathways to the LiF/Al electrode. This work is supported by the Wright Center for Photovoltaic Innovation and Commercialization, the Institute for Materials Research and the Center for Affordable Nanoengineering of Polymeric Biomedical Devices.

  15. INTERIOR VIEW WITH LARGE PIPE CASTING MACHINE CASTING A 48' ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    INTERIOR VIEW WITH LARGE PIPE CASTING MACHINE CASTING A 48' PIPE OPERATOR SPRAYING A POWDER TO HELP SOLIDIFY THE PIPE BEING CENTRIFUGALLY CAST. - United States Pipe & Foundry Company Plant, Pipe Casting & Testing Area, 2023 St. Louis Avenue at I-20/59, Bessemer, Jefferson County, AL

  16. Casting in Sport

    PubMed Central

    DeCarlo, Mark; Malone, Kathy; Darmelio, John; Rettig, Arthur

    1994-01-01

    Attempts by sports medicine professionals to return high school athletes with hand and wrist injuries to competition quickly and safely have been the source of confusion and debate on many playing fields around the country. In addition to the differing views regarding the appropriateness of playing cast usage in high school football, a debate exists among sports medicine professionals as to which material is best suited for playing cast construction. Materials used in playing cast construction should be hard enough to provide sufficient stabilization to the injured area and include adequate padding to absorb blunt impact forces. The purpose of the biomechanical portion of this investigation was to attempt to determine the most appropriate materials for use in constructing playing casts for the hand and wrist by assessing different materials for: 1) hardness using a Shore durometer, and 2) ability to absorb impact using a force platform. Results revealed that RTV11 and Scotchcast were the “least hard” of the underlying casting materials and that Temper Stick foam greatly increased the ability of RTV11 to absorb impact. Assessment of the mechanical properties of playing cast materials and review of current developments in high school football rules are used to aid practitioners in choosing the most appropriate materials for playing cast construction. ImagesFig 1.Fig 2.Fig 3. PMID:16558257

  17. Extraction of agar from Gelidium sesquipedale (Rhodopyta) and surface characterization of agar based films.

    PubMed

    Guerrero, P; Etxabide, A; Leceta, I; Peñalba, M; de la Caba, K

    2014-01-01

    The chemical structure of the agar obtained from Gelidium sesquipedale (Rhodophyta) has been determined by (13)C nuclear magnetic resonance ((13)C NMR) and Fourier transform infrared spectroscopy (FTIR). Agar (AG) films with different amounts of soy protein isolate (SPI) were prepared using a thermo-moulding method, and transparent and hydrophobic films were obtained and characterized. FTIR analysis provided a detailed description of the binding groups present in the films, such as carboxylic, hydroxyl and sulfonate groups, while the surface composition was examined using X-ray photoelectron spectroscopy (XPS). The changes observed by FTIR and XPS spectra suggested interactions between functional groups of agar and SPI. This is a novel approach to the characterization of agar-based films and provides knowledge about the compatibility of agar and soy protein for further investigation of the functional properties of biodegradable films based on these biopolymers. PMID:24274535

  18. Roll Casting of Aluminum Alloy Clad Strip

    SciTech Connect

    Nakamura, R.; Tsuge, H. [Graduate School of Osaka Institute of Technology (Japan); Haga, T. [Osaka Institute of Technology, 5-16-1 Omiya Asahiku Osaka city 535-8585 (Japan); Watari, H. [Tokyo Institute of Technology, 4259 Nagatsuda Midoriku Yokohama city 226-8502 (Japan); Kumai, S. [Gunma University, 1-5-1 tenjin cho Kiryu city 376-8515 (Japan)

    2011-01-17

    Casting of aluminum alloy three layers of clad strip was tried using the two sets of twin roll casters, and effects of the casting parameters on the cladding conditions were investigated. One twin roll caster was mounted on the other twin roll caster. Base strip was 8079 aluminum alloy and overlay strips were 6022 aluminum alloy. Effects of roll-load of upper and lower casters and melt temperature of the lower caster were investigated. When the roll-load of the upper and lower caster was large enough, the overlay strip could be solidified and be connected. The overlay strip could be connected when the melt of the overlay strip cast by the lower caster was low enough. Sound three layers of clad strip could be cast by proper conditions.

  19. Bismuth Telluride and Antimony Telluride Based Co-evaporated Thermoelectric Thin Films: Technology, Characterization, and Optimization

    NASA Astrophysics Data System (ADS)

    Ghafouri, Niloufar

    Thermoelectric (TE) materials have been widely investigated and used in a variety of systems such as solid-state coolers, infrared detectors, and power generators. Integration of TE thin films in micro-scale systems offers advantages such as integration, size, and weight for many new applications. In order to provide design flexibility for thermoelectric microsystems, high-quality TE thin films with good adhesion and uniformity are needed on a variety of substrates. Motivated by the applications of TE materials in microsystems, the goal of this dissertation is to explore the technology and characterization of co-evaporated high quality (Bi,Sb)Te-based thin films on various substrates. Thermal evaporation is an attractive thin film deposition technique because of its relative simplicity, reproducibility, ease of process control, and high throughput. Characterization techniques are applied to a variety of TE films in order to enhance physical understanding of the effects of deposition conditions, substrate material/crystallinity, and substrate preparation on film properties. This dissertation shows that the grain size, composition, and TE properties of thin films depend strongly on the co-evaporation process conditions including substrate material, deposition substrate temperature, and elemental flux ratio. Our results show that maximum power factors are achieved on Poly-Si and Kapton® substrates at Tsub= 270 °C for n-type Bi2Te 3 films, and on oxide and poly-Si substrates at Tsub= 250°C for p-type Sb2Te3 films. The optimum (Bi,Sb)Te-based binary films have tellurium atomic percentage of about 60%. This work moves beyond co-evaporation of binary alloys towards advanced thermoelectric films of ternary alloys. It demonstrates co-evaporation as a low-cost process for the deposition of telluride-based ternary films for the first time. One of the main challenges in devices using TE thin films compared to bulk material is the increasing importance of contact resistance. Contact resistance can cause major degradation in TE microsystems performance. In this dissertation, test structures are introduced with novel material-shape combinations for minimization of electrical contact resistivity between (Bi,Sb)Te-based thin films and various contact metals. Characterization of resistivity based on the contact material, physical structure, and surface treatment facilitates control and reduction of electrical contact resistance.

  20. Chitosan based edible films and coatings: a review.

    PubMed

    Elsabee, Maher Z; Abdou, Entsar S

    2013-05-01

    Chitosan is a biodegradable biocompatible polymer derived from natural renewable resources with numerous applications in various fields, and one of which is the area of edible films and coatings. Chitosan has antibacterial and antifungal properties which qualify it for food protection, however, its weak mechanical properties, gas and water vapor permeability limit its uses. This review discusses the application of chitosan and its blends with other natural polymers such as starch and other ingredients for example essential oils, and clay in the field of edible films for food protection. The mechanical behavior and the gas and water vapor permeability of the films are also discussed. References dealing with the antimicrobial behavior of these films and their impact on food protection are explored. PMID:23498203

  1. TiNi-based thin films for MEMS applications

    E-print Network

    Fu, Yongqing

    In this paper, some critical issues and problems in the development of TiNi thin films were discussed, including preparation and characterization considerations, residual stress and adhesion, frequency improvement, fatigue ...

  2. Characterization of films based on chitosan lactate and its blends with oxidized starch and gelatin.

    PubMed

    Kowalczyk, Dariusz; Kordowska-Wiater, Monika; Nowak, Jakub; Baraniak, Barbara

    2015-06-01

    Minimal inhibitory concentration (MIC) of chitosan lactate (CHL) was tested against bacteria and phytopathogenic fungi. Then, the structural, physicochemical and antimicrobial properties of films based on CHL, oxidized potato starch (OPS), and gelatin (GEL) were investigated. With the exception of Rhizopus nigricans, CHL was effective against the target organisms. Gram-positive bacteria (Staphylococcus aureus and Bacillus cereus) were more sensitive to CHL than Gram-negative bacteria (Pectobacterium carotovorum and Escherichia coli). Cryo-SEM images showed total miscibility between the polymers in the blends and the ATR-FTIR spectra revealed that there was an interaction among the polymeric components. Pure CHL films displayed the highest moisture content (25.51%), water vapor permeability (48.78gmmm(-2)d(-1)kPa(-1)), and the lowest tensile and puncture strength (2.00 and 1.45MPa, respectively) among the studied films. CHL50/GEL50 films had lower permeability, higher mechanical strength, and lower elongation compared to CHL50/OPS50 films. Films obtained from CHL and CHL50/GEL50 were completely water-soluble and did not show sorbitol recrystallization. The incorporation of CHL into OPS and GEL films did not affect their transparency and improved UV-blocking capacity. CHL films were the only ones that exhibited antibacterial efficiency. Antifungal activities against Alternaria alternata and Monilinia fructigena were detected for CHL and CHL50/GEL50 films. PMID:25841370

  3. Effect of third-element additions on properties of Co-Cr-based films

    NASA Astrophysics Data System (ADS)

    Sagoi, Masayuki; Inoue, Tetsuo

    1990-05-01

    The fundamental effects of adding several elements to the Co-Cr system on the properties of Co-Cr-based films were extensively investigated. Tantalum, molybdenum, vanadium, and rhenium were chosen as the additives. A large amount of each element was added to a Co-17-at. % Cr film. Ta addition improved the squareness and suppressed the in-plane coercive force without lowering the perpendicular coercive force for the films with perpendicular magnetization. All the additives were effective in suppressing the grain growth. The ternary alloy films were likely to have finer grains than Co-Cr films. Ta was found to be the most advantageous in a wide range of the content, from the total balance of squareness, coercive force, and grain size. The recording characteristics of Co-Cr-Ta films were also examined in comparison with those of Co-Cr films. The recording density and the signal-to-noise ratio of Co-Cr-Ta films were appreciably higher than those of Co-Cr films.

  4. Characterization of ammonium dichromate doped PVA films based waveguides

    Microsoft Academic Search

    Poonam Vashistha; Shiv Shankar Gaur; K. N. Tripathi

    2007-01-01

    We report here the study of refractive index and Propagation loss of ammonium dichromate doped poly (vinyl alcohol) thin films\\u000a by using a prism coupling technique. Transmissions of the doped films have been measured. It has been observed that doping\\u000a of ammonium dichromate increase the refractive index. Propagation losses are found to decrease up to dye concentration 0.02%\\u000a and thereafter

  5. Fundamentals of Nitride-Based Superlattice Thin Films

    Microsoft Academic Search

    Anita Madan; Scott A. Barnett

    \\u000a The structure and mechanical properties of superlattices have been studied since the 1960’s.[1] The term “superlattice” in this case refers to any thin-film structure with a periodic composition modulation in the film\\u000a growth direction. Superlattices are characterized by the distance between successive pair of layers, A, known as the ‘bilayer\\u000a repeat period’. In early work, Hilliard and co-workers used superlattices

  6. Solution based synthesis of cadmium tungstate scintillation films

    Microsoft Academic Search

    Huamei Shang

    2006-01-01

    In this dissertation, I will summarize my experimental study on the fabrication of oxide scintillation films for X-rays, gamma-rays, and neutrons detection through microstructure engineering by low cost solution methods. The research work has been focused mainly on the fabrication of oxide scintillation films with sol-gel processing, hydrothermal method, taking CdWO4 (CWO) as a model system because of its high

  7. An interferometric humidity sensor based on a thin gelatin film

    NASA Astrophysics Data System (ADS)

    Calixto, Sergio; Montes-Perez, Areli

    2014-07-01

    Gelatin thin films inserted in a Mach - Zehnder interferometer were used to monitor Relative Humidity (RH). When RH varied, gelatin film thickness and refractive index also changed. As a result interference pattern moved horizontally. A fixed detector, with a pinhole in front of it, was placed at the interference pattern. It sampled the pattern when it moved. These intensity values were used to find a calibration plot relating intensity as a function of RH.

  8. The surface structure and thermal properties of novel polymer composite films based on partially phosphorylated poly(vinyl alcohol) with aluminum phosphate.

    PubMed

    Mohamed Saat, Asmalina; Johan, Mohd Rafie

    2014-01-01

    Partially phosphorylated polyvinyl alcohol (PPVA) with aluminum phosphate (ALPO4) composites was synthesized by solution casting technique to produce (PPVA)(100-y) - (ALPO4)(y) (y?=?0, 1, and 2). The surface structure and thermal properties of the films were characterized using Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The results showed that the films have higher thermal stability with strong bonding between PPVA and ALPO4. PMID:25506069

  9. The Surface Structure and Thermal Properties of Novel Polymer Composite Films Based on Partially Phosphorylated Poly(vinyl alcohol) with Aluminum Phosphate

    PubMed Central

    Mohamed Saat, Asmalina

    2014-01-01

    Partially phosphorylated polyvinyl alcohol (PPVA) with aluminum phosphate (ALPO4) composites was synthesized by solution casting technique to produce (PPVA)100?y ? (ALPO4)y (y?=?0, 1, and 2). The surface structure and thermal properties of the films were characterized using Fourier transform infrared (FTIR) spectroscopy and thermogravimetric analysis (TGA). The results showed that the films have higher thermal stability with strong bonding between PPVA and ALPO4. PMID:25506069

  10. Influence of molecular rigidity on interfacial ordering in diphenyl-based polysiloxane films

    E-print Network

    Dutta, Pulak

    -ray reflectivity (XRR) shows significant differences between the ordering in thin films of diphenyl-based siloxane surface. The results indicate unambiguously that the chain stiffness of siloxanes governs the degree

  11. Design and modeling of a PZT thin film based piezoelectric micromachined ultrasonic transducer (PMUT)

    E-print Network

    Smyth, Katherine Marie

    2012-01-01

    The design and modelling framework for a piezoelectric micromachined ultrasonic transducer (PMUT) based on the piezoelectric thin film deposition of lead zirconate titanate (PZT) is defined. Through high frequency vibration ...

  12. Thin film lithium-based batteries and electrochromic devices fabricated with nanocomposite electrode materials

    DOEpatents

    Gillaspie, Dane T; Lee, Se-Hee; Tracy, C. Edwin; Pitts, John Roland

    2014-02-04

    Thin-film lithium-based batteries and electrochromic devices (10) are fabricated with positive electrodes (12) comprising a nanocomposite material composed of lithiated metal oxide nanoparticles (40) dispersed in a matrix composed of lithium tungsten oxide.

  13. Growth of hierarchical based ZnO micro/nanostructured films and their tunable wettability behavior

    NASA Astrophysics Data System (ADS)

    Suresh Kumar, P.; Dhayal Raj, A.; Mangalaraj, D.; Nataraj, D.; Ponpandian, N.; Li, Lin; Chabrol, G.

    2011-05-01

    Hierarchical zinc oxide (ZnO) micro/nanostructured thin films were grown onto as-prepared and different annealed ZnO seed layer films by a simple two step chemical process. A cost effective successive ionic layer adsorption and reaction (SILAR) method was employed to grow the seed layer films at optimal temperature (80 °C) and secondly, different hierarchical based ZnO structured thin films were deposited over the seed layered films by chemical bath deposition (CBD). The influence of seed layer on the structural, surface morphological, optical and wettability behavior of the ZnO thin films were systematically investigated. The XRD analysis confirms the high crystalline nature of both the seed layer and corresponding ZnO micro/nanostructured films with a perfect hexagonal structure oriented along (0 0 2) direction. The surface morphology revels a complex and orientated hierarchical based ZnO structured films with diverse shapes from plates to hexagonal rod-like crystal to tube-like structure and even much more complex needle-like shapes during secondary nucleation, by changing the seed layer conditions. The water contact angle (WCA) measurements on hierarchical ZnO structured films are completely examined to study its surface wettability behavior for its suitability in future self-cleaning application. Photoluminescence (PL) spectra of the ZnO structured film exhibit UV and visible emissions in the range of 420-500 nm. The present approach demonstrates its potential for low-temperature, large-scale, controlled synthesis of crystalline hierarchical ZnO nanostructures films.

  14. Crosslinking and composition influence the surface properties, mechanical stiffness and cell reactivity of collagen-based films.

    E-print Network

    Grover, CN; Gwynne, JH; Pugh, N; Hamaia, S; Farndale, RW; Best, Serena Michelle; Cameron, Ruth Elizabeth

    2012-07-09

    This study focuses on determining the effect of varying the composition and crosslinking of collagen-based films on their physical properties and interaction with myoblasts. Films composed of collagen or gelatin and crosslinked with a carbodiimide...

  15. Predicting Pattern Tooling and Casting Dimensions for Investment Casting - Phase II

    SciTech Connect

    Sabau, Adrian S [ORNL

    2005-09-01

    The investment casting process allows the production of complex-shape parts and close dimensional tolerances. One of the most important phases in the investment casting process is the design of the pattern die. Pattern dies are used to create wax patterns by injecting wax into dies. The wax patterns are used to create a ceramic shell by the application of a series of ceramic coatings, and the alloy is cast into the dewaxed shell mold (Fig. 1.1). However, the complexity of shape and the close dimensional tolerances required in the final casting make it difficult to determine tooling dimensions. The final linear dimension of the casting depends on the cumulative effects of the linear expansions or contractions in each step of the investment casting process (Fig. 1.2). In most cases, the mold geometry or cores restrict the shrinkage of the pattern or the cast part, and the final casting dimensions may be affected by time-dependent processes such as viscoelastic deformation of the wax, and viscoplastic creep and plastic deformations of the shell and alloy. The pattern die is often reworked several times to produce castings whose dimensions are within acceptable tolerances. To date, investment casting technology has been based on hands-on training and experience. Technical literature is limited to experimental, phenomenological studies aimed at obtaining empirical correlations for quick and easy application in industry. The goal of this project was to predict casting dimensions for investment castings in order to meet blueprint nominal during the first casting run. Several interactions have to be considered in a coupled manner to determine the shrinkage factors: these are the die-wax, wax-shell, and shell-alloy interactions (as illustrated in Fig. 1.3). In this work, the deformations of the die-wax and shell-alloy systems were considered in a coupled manner, while the coupled deformation of the wax-shell system was not considered. Future work is needed in order to deliver to industry a computer program in which all three systems are coupled for determining the dimensions of the wax pattern, the shell mold, and casting in a sequential but coupled manner.

  16. A study of impedance spectroscopy of nanocrystalline ceria-based solid electrolytical film

    NASA Astrophysics Data System (ADS)

    Zhang, Dexin; Liu, Zuli; Yue, Huimin; Yao, Kailun

    2004-02-01

    The nanocrystalline ceria-based solid electrolytical thin film was prepared by using the sol-gel dip-coating method. The complex impedance spectroscopy of the films was measured at different dopant concentrations and various measurement temperatures. It was found that the complex impedance spectroscopy of the nanocrystalline ceria-based thin films posses two stable residual grain boundary arcs at the annealed temperature of 700°C, and that the total impedance is decreased with increase in the dopant concentration. It was also found that the residual grain boundary arc is kept as two arcs but shrunk as measurement temperature is raised.

  17. Sol—gel processed TiO 2-based thin films as innovative humidity sensors

    Microsoft Academic Search

    Giampiero Montesperelli; Antonio Pumo; Enrico Traversa; Gusmano; Andrea Bearzotti; Angelo Montenero; Guglielmina Gnappi

    1995-01-01

    Active elements for humidity sensors based on alkali-doped and undoped TiO2 films have been prepared by the sol-—gel technique. TiO2-based films are deposited onto Al2O3 substrates with comb-type Au electrodes by dip-coating, from the appropriate solutions, to obtain four different compositions of 1, 3, 6, and 10 at.% Li and K, with respect to the alkali metal\\/Ti system. The humidity-sensing

  18. Metal-organic chemical vapor deposition of cadmium oxide-based transparent conductors: Precursor design, film growth, and film characterization

    NASA Astrophysics Data System (ADS)

    Metz, Andrew William

    2003-07-01

    The growing importance of cadmium containing thin films and the desire for their efficient deposition has necessitated the development of high performance MOCVD precursors. To this end, a series of low-melting, and thermally-stable cadmium MOCVD precursors has been synthesized, characterized, and implemented in the growth of highly conductive and transparent CdO-based thin films. One member of the series, bis(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)(N,N-diethyl-N ', N'-dimethyl-ethylenediamine)cadmium(II), Cd(hfa)2(N,N-DE-N' ,N'-DMEDA), represents a particularly significant improvement over previously available Cd precursors owing to its low melting point, and robust thermal stability. This precursor will allow careful control of composition and growth rates in complex cadmium-containing oxide systems owing to the elimination of sintering effects detrimental to reproducible growth with solid precursors. Materials with high electrical conductivity and optical transparency are needed for future flat panel display, solar energy, and other opto-electronic technologies. High quality Cd1-xInxO films with been deposited utilizing our new class of MOCVD precursors. The x = 0.05 film, with conductivity of 17,000 S/cm, carrier mobility of 70 cm2/V·s, and wide visible region optical transparency window considerably exceed the corresponding parameters for commercial indium-tin oxide (ITO). A detailed understanding of the fundamental aspects of charge transport in degenerate semiconductors is of great interest. In order to elucidate the importance of individual scattering mechanisms in TCO materials, high-quality CdO films were grown by MOCVD in parallel on glass and single-crystal MgO (100) between 300°C and 412°C. Enhanced mobilities observed for highly biaxially textured films grown on MgO (100) vs. glass are attributed, on the basis of DC charge transport measurements and microstructure analysis, to a reduction in neutral impurity scattering and/or to a more densely packed grain microstructure. Although single grained films grown on MgO (100) exhibit greater mobilities than analogues with discrete ˜100 nm grains and similar texture, this effect is attributed, on the basis of charge transport and Hall effect measurements as well as optical reflectivity analysis to small differences in carrier concentration, rather than to a reduction in grain boundary scattering. Conductivities and mobilities as high as 11,000 S/cm and 307 cm2/V·s, respectively, are obtained for epitaxial single-grained CdO films grown in situ on MgO (100).

  19. Influence of three classic chromium-based transitions on the behavior of film/substrate interface in diamond-like carbon films

    NASA Astrophysics Data System (ADS)

    Yang, Xi; Yu, Xiang; Wang, Yonghui; Shu, Wen; Hua, Meng

    2013-12-01

    Three diamond-like carbon (DLC) films with classic chromium-based transitions containing a typical step-like gradient, a linear gradient and a modulation period, were deposited using a mid-frequency dual-magnetron sputtering system. Studies were performed on samples with almost the same Cr content to compare the interfacial structures and compositions of the three chromium-based transitions, and to investigate the internal stress, adhesion strength, and fracture toughness of the films. The synergistic effect of the transitions deterministically influenced the interfacial properties. The films with a linear gradient had the optimal interfacial properties when compared with the other two films.

  20. Elevated temperature mechanical properties and residual tensile properties of two cast superalloys and several nickel-base oxide dispersion strengthened alloys

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D.

    1981-01-01

    The elevated temperature tensile, stress-rupture and creep properties and residual tensile properties after creep straining have been determined for two cast superalloys and several wrought Ni-16Cr-4Al-yttria oxide dispersion strengthened (ODS) alloys. The creep behavior of the ODS alloys is similar to that of previously studied ODS nickel alloys. In general, the longitudinal direction is stronger than the long transverse direction, and creep is at least partially due to a diffusional creep mechanism as dispersoid-free zones were observed after creep-rupture testing. The tensile properties of the nickel-base superalloy B-1900 and cobalt-base superalloy MAR-M509 are not degraded by prior elevated temperature creep straining (at least up to 1 pct) between 1144 and 1366 K. On the other hand, the room temperature tensile properties of ODS nickel-base alloys can be reduced by prior creep strains of 0.5 pct or less between 1144 and 1477 K, with the long transverse direction being more susceptible to degradation than the longitudinal direction.

  1. Casting Characteristics of Aluminum Die Casting Alloys

    SciTech Connect

    Makhlouf M. Makhlouf; Diran Apelian

    2002-02-05

    The research program investigates the casting characteristics of selected aluminum die casting alloys. Specifically, the alloys' tendencies towards die soldering and sludge formation, and the alloys' fluidity and machinability are evaluated. It was found that: When the Fe and Mn contents of the alloy are low; caution has to be taken against possible die soldering. When the alloy has a high sludge factor, particularly a high level of Fe, measures must be taken to prevent the formation of large hardspots. For this kind of alloy, the Fe content should be kept at its lowest allowable level and the Mn content should be at its highest possible level. If there are problems in die filling, measures other than changing the alloy chemistry need to be considered first. In terms of alloy chemistry, the elements that form high temperature compounds must be kept at their lowest allowable levels. The alloys should not have machining problems when appropriate machining techniques and machining parameters are used.

  2. Fabrication and mechanical characterization of biodegradable and synthetic polymeric films: Effect of gamma radiation

    NASA Astrophysics Data System (ADS)

    Akter, Nousin; Khan, Ruhul A.; Salmieri, Stephane; Sharmin, Nusrat; Dussault, Dominic; Lacroix, Monique

    2012-08-01

    Chitosan (1 wt%, in 2% aqueous acetic acid solution) and starch (1 wt%, in deionised water) were dissolved and mixed in different proportions (20-80 wt% chitosan) then films were prepared by casting. Tensile strength and elongation at break of the 50% chitosan containing starch-based films were found to be 47 MPa and 16%, respectively. It was revealed that with the increase of chitosan in starch, the values of TS improved significantly. Monomer, 2-butane diol-diacrylate (BDDA) was added into the film forming solutions (50% starch-based), then casted films. The BDDA containing films were irradiated under gamma radiation (5-25 kGy) and it was found that strength of the films improved significantly. On the other hand, synthetic petroleum-based polymeric films (polycaprolactone, polyethylene and polypropylene) were prepared by compression moulding. Mechanical and barrier properties of the films were evaluated. The gamma irradiated (25 kGy) films showed higher strength and better barrier properties.

  3. Antimicrobial packaging of chicken fillets based on the release of carvacrol from chitosan/cyclodextrin films.

    PubMed

    Higueras, Laura; López-Carballo, Gracia; Hernández-Muñoz, Pilar; Catalá, Ramón; Gavara, Rafael

    2014-10-01

    Chitosan/cyclodextrin films (CS:CD) incorporating carvacrol were obtained by casting, and conditioned at 23°C and 75% relative humidity prior to being immersed in liquid carvacrol until they reached sorption equilibrium. In a previous work, the in vitro antimicrobial activity of these films was studied. In this work, active films were used to inhibit microbial growth in packaged chicken breast fillets. Samples of CS:CD films loaded with carvacrol, of different sizes and thus with different quantities of antimicrobial agent, were stuck to the aluminium lid used to seal PP/EVOH/PP cups containing 25g of chicken fillets. These samples were stored for 9days at 4°C. The packages were hermetically sealed and it was confirmed that they provided an infinite barrier to carvacrol. The partition of the antimicrobial agent within the food/packaging system was analysed. The antimicrobial devices rapidly released a large percentage of the agent load, amounts that were gained by the adhesive coating of the lid and especially by the chicken fillets. The latter were the main sorbent phase, with average concentrations ranging between 200 and 5000mg/Kg during the period of storage. The microbiota of the packaged fresh chicken fillets - mesophiles, psychrophiles, Pseudomonas spp., enterobacteria, lactic acid bacteria and yeasts and fungi - were analysed and monitored during storage. A general microbial inhibition was observed, increasing with the size of the active device. Inhibition with a 24cm(2) device ranged from 0.3 log reductions against lactic acid bacteria to 1.8logs against yeasts and fungi. However, the large amount of antimicrobial that was sorbed or that reacted with the fillet caused an unacceptable sensory deterioration. These high sorption values are probably due to a great chemical compatibility between chicken proteins and carvacrol. PMID:25087205

  4. 3D printing technique applied to rapid casting

    Microsoft Academic Search

    Elena Bassoli; Andrea Gatto; Luca Iuliano; Maria Grazia Violante

    2007-01-01

    Purpose – The purpose of this paper is to verify the feasibility and evaluate the dimensional accuracy of two rapid casting (RC) solutions based on 3D printing technology: investment casting starting from 3D-printed starch patterns and the ZCast process for the production of cavities for light-alloys castings. Design\\/methodology\\/approach – Starting from the identification and design of a benchmark, technological prototypes

  5. Factors affecting the moisture permeability of lipid-based edible films: a review.

    PubMed

    Morillon, Valérie; Debeaufort, Frédéric; Blond, Geneviève; Capelle, Martine; Voilley, Andrée

    2002-01-01

    Moisture transfers inside food products could be controlled or limited by the use of edible films. These are usually based on hydrophobic substances such as lipids to improve barrier efficiency. Water permeability of films is affected by many factors, depending on both the nature of barrier components, the film structure (homogeneous, emulsion, multilayer, etc.), crystal type, shape, size and distribution of lipids, and thermodynamics such as temperature, vapor pressure, or the physical state of water in contact to the films. After a brief presentation of lipids and hydrophobic substances used as moisture barrier, cited in the scientific literature, this article reviews all of the parameters affecting barrier performances of edible films and coatings. PMID:11833637

  6. A micro force sensor based on a single ZnO belt coated with chromium film.

    PubMed

    Ren, Xiaoyan; Yang, Xing; Zhou, Zhaoying; Li, Jinming; Liu, Jing

    2010-11-01

    A micro force sensor was fabricated using a single ZnO belt coated with ultra thin Cr film. As a result of the piezoresistive effect of the ultra thin (in nano-scale) Cr film, the bending of the belt led to the change in the resistance of ultra thin Cr film. Based on the mechanics of the materials, the relationship between the deformation and the force was calculated, and a linear relationship between the bending force and the resistance of Cr thin film was deduced at small bending regions. Dielectrophoresis, focused ion beam (FIB) and sputtering were used in the process of the micro force sensor. The experimental results show that the resistance of Cr film is sensitive to the bending force and demonstrate the potential for developing a new class of stable and sensitive nano-sized structures for force sensing. PMID:21137908

  7. High-energy-density sol-gel thin film based on neat 2-cyanoethyltrimethoxysilane.

    PubMed

    Kim, Yunsang; Kathaperumal, Mohanalingam; Smith, O'Neil L; Pan, Ming-Jen; Cai, Ye; Sandhage, Kenneth H; Perry, Joseph W

    2013-03-13

    Hybrid organic-inorganic sol-gel dielectric thin films from a neat 2-cyanoethyltrimethoxysilane (CNETMS) precursor have been fabricated and their permittivity, dielectric strength, and energy density characterized. CNETMS sol-gel films possess compact, polar cyanoethyl groups and exhibit a relative permittivity of 20 at 1 kHz and breakdown strengths ranging from 650 V/?m to 250 V/?m for film thicknesses of 1.3 to 3.5 ?m. Capacitors based on CNETMS films exhibit extractable energy densities of 7 J/cm(3) at 300 V/?m, as determined by charge-discharge and polarization-electric field measurements, as well as an energy extraction efficiency of ~91%. The large extractable energy resulting from the linear dielectric polarization behavior suggests that CNETMS films are promising sol-gel materials for pulsed power applications. PMID:23427818

  8. Atomic Oxygen Sensors Based on Nanograin ZnO Films Prepared by Pulse Laser Deposition

    SciTech Connect

    Wang Yunfei; Chen Xuekang; Li Zhonghua; Zheng Kuohai; Wang Lanxi; Feng Zhanzu; Yang Shengsheng [National Key Laboratory of Vacuum and Cryogenics Technology and Physics, Lanzhou Institute of Physics, Lanzhou 730000 (China)

    2009-01-05

    High-quality nanograin ZnO thin films were deposited on c-plane sapphire (Al{sub 2}O{sub 3}) substrates by pulse laser deposition (PLD). Scanning electron microscopy (SEM) and x-ray diffraction (XRD) were used to characterize the samples. The structural and morphological properties of ZnO films under different deposition temperature have been investigated before and after atomic oxygen (AO) treatment. XRD has shown that the intensity of the (0 0 2) peak increases and its FWHM value decreases after AO treatment. The AO sensing characteristics of nano ZnO film also has been investigated in a ground-based atomic oxygen simulation facility. The results show that the electrical conductivity of nanograin ZnO films decreases with increasing AO fluence and that the conductivity of the films can be recovered by heating.

  9. A silane-based electroactive film prepared in an imidazolium chloroaluminate molten salt

    SciTech Connect

    Carlin, R.T. (Air Force Academy, CO (United States). Frank J. Seiler Research Lab.); Osteryoung, R.A. (North Carolina State Univ., Raleigh, NC (United States). Dept. of Chemistry)

    1994-07-01

    Electrochemical oxidation of Ph[sub 3]SiCl (Ph = phenyl) in the room-temperature molten salt AlCl[sub 3]:EMICl (EMICl = 1-ethyl-3-methylimidazolium chloride) results in the formation of an adherent electroactive film on the surface of solid electrodes. The film is reversibly oxidized and reduced in the molten salt and is conducting when in the oxidized state. Based on x-ray photoelectron spectroscopy analysis, the film consists of both a silane and an imidazole component, and the charge storage properties of the film are localized on the heterocyclic rings. This electroactive film compares favorably to other conducting polymers currently being investigated as positive electrodes in room-temperature molten salt batteries.

  10. VAl-Based Thermoelectric Thin Films Prepared by a Sputtering Technique

    NASA Astrophysics Data System (ADS)

    Furuta, Yukihiro; Kato, Keisuke; Miyawaki, Tetsuya; Asano, Hidefumi; Takeuchi, Tsunehiro

    2014-06-01

    In this study we prepared thin-film samples of the Fe2VAl-based Heusler phase by means of radio-frequency magnetron sputtering. The Fe2VAl-based Heusler phase was grown epitaxially, keeping the root-mean-square surface roughness smoother than 20 nm, even when the thickness of the samples exceeded 1000 nm. The composition of the samples was controlled via both target composition and the area of a small vanadium chip placed on the target. We succeeded in obtaining samples that were free from precipitation of a secondary phase. It was confirmed that the lattice thermal conductivity of the film samples can be reduced, irrespective of film thickness, and that the Seebeck coefficient was essentially the same as that of the bulk samples. These experimental results indicate that thin-film Fe2VAl-based Heusler alloys have potential as practical thermoelectric materials.

  11. Prism coupler and microscopic investigations of DNA films

    NASA Astrophysics Data System (ADS)

    Samoc, Anna; Galewski, Zbigniew; Samoc, Marek; Grote, James G.

    2007-09-01

    DNA is a polyelectrolyte capable of forming thin films with interesting optical properties. We investigated refractive indices and optical anisotropy of films of the native, sodium ion-based DNA (Na-DNA) and DNA bearing the cetyltrimethylammonium ion (DNA-CTMA) using a prism coupler technique. The light polarization direction was either parallel (n TE) or perpendicular to the surface plane of the films (n TM). The index values and the birefringence of DNA films vary considerably depending on the type of the counter-ion, the film fabrication method and the relative humidity (RH) of the environment. A high negative birefringence in films of Na-DNA, n TE-n TM = -0.03 at an RH ~ 55 %, was measured in solution-cast films, indicating that the optically anisotropic DNA molecules are aligned in the plane parallel to the film surface. Refractive indices of DNA-CTMA thin films were smaller and more isotropic than those for films of Na-DNA polymer. The prism coupler reflectance curves showed a hysteresis of the index values when the RH of a DNA-CTMA film environment varied. Polarization microscopy studies showed liquid-crystalline textures at the edges of Na-DNA and DNA-CTMA films.

  12. Microstructure and stress-rupture life of polycrystal, directionally solidified, and single crystal castings of nickel-based IN 939 superalloy

    SciTech Connect

    Jovanovic, M.T.; Miskovic, Z.; Lukic, B. [Inst. of Nuclear Sciences Vinca, Belgrade (Yugoslavia). Dept. of Materials Science] [Inst. of Nuclear Sciences Vinca, Belgrade (Yugoslavia). Dept. of Materials Science

    1998-04-01

    A comparative investigation of microstructural and mechanical properties (stress-rupture life) in conventionally cast, directionally solidified, and single crystal IN 939 superalloy has been undertaken. Directional castings possess only a few columnar grains, all oriented in the <100> crystallographic direction, whereas only one grain is present in a single crystal. Single crystals are characterized by the highest values of stress-rupture life, much higher than those of directionally solidified and, especially, polycrystal castings, which is accounted for by the absence of grain boundaries.

  13. Verification of Gamma Knife extend system based fractionated treatment planning using EBT2 film

    SciTech Connect

    Natanasabapathi, Gopishankar; Bisht, Raj Kishor [Gamma Knife Unit, Department of Neurosurgery, Neurosciences Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029 (India)] [Gamma Knife Unit, Department of Neurosurgery, Neurosciences Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029 (India)

    2013-12-15

    Purpose: This paper presents EBT2 film verification of fractionated treatment planning with the Gamma Knife (GK) extend system, a relocatable frame system for multiple-fraction or serial multiple-session radiosurgery.Methods: A human head shaped phantom simulated the verification process for fractionated Gamma Knife treatment. Phantom preparation for Extend Frame based treatment planning involved creating a dental impression, fitting the phantom to the frame system, and acquiring a stereotactic computed tomography (CT) scan. A CT scan (Siemens, Emotion 6) of the phantom was obtained with following parameters: Tube voltage—110 kV, tube current—280 mA, pixel size—0.5 × 0.5 and 1 mm slice thickness. A treatment plan with two 8 mm collimator shots and three sectors blocking in each shot was made. Dose prescription of 4 Gy at 100% was delivered for the first fraction out of the two fractions planned. Gafchromic EBT2 film (ISP Wayne, NJ) was used as 2D verification dosimeter in this process. Films were cut and placed inside the film insert of the phantom for treatment dose delivery. Meanwhile a set of films from the same batch were exposed from 0 to 12 Gy doses for calibration purposes. An EPSON (Expression 10000 XL) scanner was used for scanning the exposed films in transparency mode. Scanned films were analyzed with inhouse written MATLAB codes.Results: Gamma index analysis of film measurement in comparison with TPS calculated dose resulted in high pass rates >90% for tolerance criteria of 1%/1 mm. The isodose overlay and linear dose profiles of film measured and computed dose distribution on sagittal and coronal plane were in close agreement.Conclusions: Through this study, the authors propose treatment verification QA method for Extend frame based fractionated Gamma Knife radiosurgery using EBT2 film.

  14. Design, Integration and Evaluation of an Artificial Intelligence-Based Control System for the Improvement of the Monitoring and Quality Control Process in the Manufacturing of Metal Casting Components

    Microsoft Academic Search

    Emma L. Mares; Jerry H. Sokolowski

    2003-01-01

    \\u000a An Artificial Intelligence-Based Control System (AIBCS) combined with Thermal Analysis (TA) is applied in this research on\\u000a the manufacturing of aluminum casting components. The AIBCS comprises three interrelated IT’s based on statistical quality\\u000a control techniques and Artificial Intelligence concepts. The IT’s integrated in the AIBCS are a Real-Time Data Acquisition\\u000a System (RTDAS), a Statistical Process Control System (SPCS) and a

  15. Bipolar strain sensor based on an ultra-thin film of single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Park, Dong-Won; Kim, Beom Soo; Park, Serin; Choi, Won-Jin; Yang, Cheol-Soo; Lee, Jeong-O.

    2014-02-01

    A bipolar strain sensor based on an ultra-thin film of single-walled carbon nanotubes (SWNTs) has been fabricated. First, a random network of SWNTs was grown on a Si substrate with thermal oxide by using chemical vapor deposition and then transferred to a transparent poly(dimethyl)siloxane (PDMS) film. A mechanical load was applied by pressing the PDMS-SWNT film with a blunt micrometer tip, and its electrical conductance was found to decrease linearly with increasing pressure. Upward bending of the flexible PDMS-SWNT film was found to yield increases in conductance whereas downward bending of the film was found to result in decreases in the conductance. We modeled the SWNT network on the PDMS film with a two-dimensional percolation system, and found that the increases (decreases) in the conductance of the film upon bending could be explained in terms of stick-density changes in the 2-D percolation system. Finally, because PDMS swells with certain organic vapors, a PDMS-SWNT film can be used as a chemical sensor for volatile organic compounds. Unlike for three-dimensional composites of SWNTs and polymers, the bipolar response upon bending and simple fabrication process for the system introduced here mean that it is an attractive candidate for tactile and motion sensor applications.

  16. Performance simulation for ferroelectric thin-film based waveguide electro-optic modulators

    NASA Astrophysics Data System (ADS)

    Sun, De-Gui; Liu, Zhifu; Huang, Yingyan; Ho, Seng-Tiong; Towner, David J.; Wessels, Bruce W.

    2005-11-01

    We simulate thin-film based electro-optic modulator structures to target low drive voltage, high-speed modulation, and small device size by using BaTiO 3 ferroelectric film as an exemplary device material with optimizing film thickness. The calculations are performed for both the case of an experimental film having reff = 35 pm/V and the case of an ideal thin-film having r51 = 730 pm/V. For the case of r51 = 730 pm/V, a new relation between the drive voltage and the interaction length is derived with respect to the special configuration of BaTiO 3 thin-films. For the optimal case of the film thickness and the waveguide design, the frequency-voltage-size performances that can be achieved include: >2.5 GHz with 0.75 V V? and 31.1 mm length, 10 GHz with 1.5 V V? and 7.8 mm length, > 40 GHz with 3.0 V V? and 1.9 mm length, and > 100 GHz with 4.8 V V? and 0.8 mm length. Various physical factors unique to the frequency-voltage-size performance trade-off of the thin-film EO modulator structures are discussed.

  17. Characterization of edible emulsified films with low affinity to water based on kefiran and oleic acid.

    PubMed

    Ghasemlou, Mehran; Khodaiyan, Faramarz; Oromiehie, Abdulrasoul; Yarmand, Mohammad Saeid

    2011-10-01

    New edible composite films based on kefiran and oleic acid (OA) at the ratio of 15, 25, and 35% (w/w) were prepared using emulsification with the aim of improving their water vapour barrier and mechanical properties. Film-forming solutions were characterized in terms of rheological properties and particle-size distribution. The impact of the incorporation of OA into the film matrix was studied by investigating the physical, mechanical, and thermal properties of the films. The water vapour permeability (WVP) of the emulsified films was reduced by approximately 33% by adding OA. The mechanical properties of kefiran films were also affected by adding OA: tensile strength was diminished, and elongation increased considerably. Differential scanning calorimetry showed that the glass transition temperature (T(g)) of the kefiran film was -16°C and was not considerably affected by adding OA. Therefore, OA could be incorporated into these films for some food-technology applications that need a low affinity toward water. PMID:21640752

  18. Coplanar Phase Shifters Based on Ferroelectric Thin Films

    Microsoft Academic Search

    Chunlin Fu; Fusheng Pan; Hongwei Chen; Shucheng Feng; Wei Cai; Chuanren Yang

    2007-01-01

    Barium strontium titanate (Ba0.6Sr0.4TiO3, short for BST) thin films were prepared by RF-magnetron sputtering. The dielectric tunability, loss tangent, remanent polarization\\u000a (2Pr) and coercive electric field (Ec) of the BST films are respectively 29.5%, 0.013, 2.29 ?C\\/cm2 and 22.27 kV\\/cm at 1 kHz and 20 V. The designed coplanar waveguide (CPW) phase shifter consists of 56 same sections. It is\\u000a shown that the fabricated

  19. Evolution of aluminide coating microstructure on nickel-base cast superalloy CM-247 in a single-step high-activity aluminizing process

    SciTech Connect

    Das, D.K.; Joshi, S.V. [Defence Metallurgical Research Lab., Hyderabad (India); Singh, V. [Banaras Hindu Univ., Varanasi (India). Dept. of Metallurgical Engineering

    1998-08-01

    This study deals with the aluminizing of a directionally cast Ni-base superalloy, namely CM-247, by a single-step process using a high-activity pack. It is observed that significant incorporation of Al into the substrate surface during aluminizing continues over a period of about 1 hour and is not restricted merely to the first few minutes, as reported in the literature. Based on the microstructural details of the coatings formed at various stages of aluminizing, it is concluded that the coating growth in the above process takes place primarily by inward Al diffusion initially, followed by an intermediate stage when the growth involves both inward Al and outward Ni diffusion. In the final stages, the outward diffusion of Ni dominates the coating formation process. The above mechanism of coating formation is different from the one that prevails in the conventional two-step high-activity coating process in that the reaction front for the formation of NiAl remains spatially stationary despite the outward diffusion of nickel during the intermediate stage. It is also shown in the present study that the content of the Al source in the pack affects the coating structure significantly. It is further demonstrated that the microstructure of the aluminide coatings depends not only on the amount of Al incorporated in the sample during aluminizing but also on the time over which the uptake of this Al takes place.

  20. High melt strength, tear resistant blown film based on poly(lactic acid)

    NASA Astrophysics Data System (ADS)

    Edmonds, Neil R.; Plimmer, Peter N.; Tanner, Chris

    2015-05-01

    A major problem associated with the commercial manufacture of thin films from PLA is inferior processing characteristics on blown film lines compared to low density polyethylene. PLA has poor melt strength (leading to bubble instability) and develops a permanent crease in the flattened film as it exits the tower of the film line. In addition, the thin film product has poor tear strength and an unacceptable `noise' level when converted into flexible packaging. Furthermore, fabricated articles based on PLA are known to show an unattractive tendency toward dimensional instability. This behaviour is associated with `cold crystallization', a phenomenon which also causes exudation of any plasticizer added for improving flexibility. Blow moulded articles based on PLA also exhibit dimensional sensitivity above 60°C. All of these issues have been overcome by the technology described in this paper. This has been accomplished without loss of the valuable compostability characteristic of PLA; this was confirmed by evaluation of film in a commercial composting operation. These results have been achieved through novel reactive compounding technology which: (a) Creates a PLA-rich structure containing long chain crosslinks, (b) generates a low glass transition temperature phase covalently bonded to the PLA structure, and (c) provides a material which performs like LDPE in a blown film manufacturing operation. The technology developed is covered by NZ Patent 580231 (3). The patent is held by UniServices Ltd, The University of Auckland, New Zealand.

  1. Solution-processed flexible transparent conductors based on carbon nanotubes and silver grid hybrid films

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Zhang, Jintao; Sundramoorthy, Ashok Kumar; Chen, Peng; Chan-Park, Mary B.

    2014-04-01

    In a simple, cost-effective, and solution-based process, a thin-film of single-walled carbon nanotubes is hybridized on a PET film which has been patterned with solution self-assembled Ag nanoparticles. Such a flexible and transparent electrode exhibits a sheet resistance down to ~5.8 ? sq-1 at ~83.7% optical transmittance. The hybrid films are stable under ambient conditions and offer excellent bendability.In a simple, cost-effective, and solution-based process, a thin-film of single-walled carbon nanotubes is hybridized on a PET film which has been patterned with solution self-assembled Ag nanoparticles. Such a flexible and transparent electrode exhibits a sheet resistance down to ~5.8 ? sq-1 at ~83.7% optical transmittance. The hybrid films are stable under ambient conditions and offer excellent bendability. Electronic supplementary information (ESI) available: Experimental details, performance of graphene-Ag hybrid and met-SWNT-Ag hybrid films. See DOI: 10.1039/c3nr06386k

  2. Intense pulsed light treatment of cadmium telluride nanoparticle-based thin films.

    PubMed

    Dharmadasa, Ruvini; Lavery, Brandon; Dharmadasa, I M; Druffel, Thad

    2014-04-01

    The search for low-cost growth techniques and processing methods for semiconductor thin films continues to be a growing area of research; particularly in photovoltaics. In this study, electrochemical deposition was used to grow CdTe nanoparticulate based thin films on conducting glass substrates. After material characterization, the films were thermally sintered using a rapid thermal annealing technique called intense pulsed light (IPL). IPL is an ultrafast technique which can reduce thermal processing times down to a few minutes, thereby cutting production times and increasing throughput. The pulses of light create localized heating lasting less than 1 ms, allowing films to be processed under atmospheric conditions, avoiding the need for inert or vacuum environments. For the first time, we report the use of IPL treatment on CdTe thin films. X-ray diffraction (XRD), optical absorption spectroscopy (UV-Vis), scanning electron microscopy (SEM) and room temperature photoluminescence (PL) were used to study the effects of the IPL processing parameters on the CdTe films. The results found that optimum recrystallization and a decrease in defects occurred when pulses of light with an energy density of 21.6 J cm(-2) were applied. SEM images also show a unique feature of IPL treatment: the formation of a continuous melted layer of CdTe, removing holes and voids from a nanoparticle-based thin film. PMID:24635698

  3. Thin film transistor based on TiOx prepared by DC magnetron sputtering.

    PubMed

    Chung, Sung Mook; Shin, Jae-Heon; Hong, Chan-Hwa; Cheong, Woo-Seok

    2012-07-01

    This paper reports on the thin film transistor (TFT) based on TiOx prepared by direct current (DC) magnetron sputtering for the application of n-type channel transparent TFTs. A ceramic TiOx target was prepared for the sputtering of the TiO2 films. The structural, optical, and electrical properties of the TiO2 films were investigated after their heat treatment. It is observed from XRD measurement that the TiO2 films show anatase structure having (101), (004), and (105) planes after heat treatment. The anatase-structure TiO2 films show a band-gap energy of approximately 3.20 eV and a transmittance of approximately 91% (@550 nm). The bottom-gate TFTs fabricated with the TiO2 film as an n-type channel layer. These devices exhibit the on-off ratio, the field-effect mobility, and the threshold voltage of about 10(4), 0.002 cm2/Vs, and 6 V, respectively. These results indicate the possibility of applying TiO2 films depositied by DC magnetron sputtering to TiO2-based opto-electronic devices. PMID:22966586

  4. Zein-based films and their usage for controlled delivery: Origin, classes and current landscape.

    PubMed

    Zhang, Yong; Cui, Lili; Che, Xiaoxia; Zhang, Heng; Shi, Nianqiu; Li, Chunlei; Chen, Yan; Kong, Wei

    2015-05-28

    Zein is a class of alcohol-soluble prolamine proteins present in maize endosperm, which was approved as a generally recognized as safe (GRAS) excipient in 1985 by the United States Food and Drug Administration (US-FDA) for film coating of pharmaceuticals, e.g., tablets. Despite its long-term application in tablet production, effects of zein coating on tablet properties are still not fully understood. Moreover, many studies have also been conducted to illustrate its potential as an active ingredient of direct compressed tablets and film-based delivery carriers. In addition, the use of zein as a functional film coating material for new biomedical applications was also widely investigated in recent reports, which involved medical devices, nanoparticles, quantum dots and nanofibers. In this review, the present status of zein in the form of a thin film and uniform layer for use as a biomedical material is discussed. In addition, studies related to the behaviors and properties of zein films are also summarized and analyzed based on published works to gain mechanistic insights into the relationship between zein film and various improved profiles. This review will benefit future prospects of the use of zein film in drug delivery and biomedical applications. PMID:25828699

  5. Low k thin films based on rf plasma-polymerized aniline

    NASA Astrophysics Data System (ADS)

    Saravanan, S.; Mathai, C. Joseph; Venkatachalam, S.; Anantharaman, M. R.

    2004-06-01

    Thermally stable materials with low dielectric constant (k<3.9) are being hotly pursued. They are essential as interlayer dielectrics/intermetal dielectrics in integrated circuit technology, which reduces parasitic capacitance and decreases the RC time constant. Most of the currently employed materials are based on silicon. Low k films based on organic polymers are supposed to be a viable alternative as they are easily processable and can be synthesized with simpler techniques. It is known that the employment of ac/rf plasma polymerization yields good quality organic thin films, which are homogenous, pinhole free and thermally stable. These polymer thin films are potential candidates for fabricating Schottky devices, storage batteries, LEDs, sensors, super capacitors and for EMI shielding. Recently, great efforts have been made in finding alternative methods to prepare low dielectric constant thin films in place of silicon-based materials. Polyaniline thin films were prepared by employing an rf plasma polymerization technique. Capacitance, dielectric loss, dielectric constant and ac conductivity were evaluated in the frequency range 100 Hz 1 MHz. Capacitance and dielectric loss decrease with increase of frequency and increase with increase of temperature. This type of behaviour was found to be in good agreement with an existing model. The ac conductivity was calculated from the observed dielectric constant and is explained based on the Austin Mott model for hopping conduction. These films exhibit low dielectric constant values, which are stable over a wide range of frequencies and are probable candidates for low k applications.

  6. Short Fiction on Film: A Relational DataBase.

    ERIC Educational Resources Information Center

    May, Charles

    Short Fiction on Film is a database that was created and will run on DataRelator, a relational database manager created by Bill Finzer for the California State Department of Education in 1986. DataRelator was designed for use in teaching students database management skills and to provide teachers with examples of how a database manager might be…

  7. Memory switches based on metal oxide thin films

    NASA Technical Reports Server (NTRS)

    Ramesham, Rajeshuni (Inventor); Thakoor, Anilkumar P. (Inventor); Lambe, John J. (Inventor)

    1990-01-01

    MnO.sub.2-x thin films (12) exhibit irreversible memory switching (28) with an OFF/ON resistance ratio of at least about 10.sup.3 and the tailorability of ON state (20) resistance. Such films are potentially extremely useful as a connection element in a variety of microelectronic circuits and arrays (24). Such films provide a pre-tailored, finite, non-volatile resistive element at a desired place in an electric circuit, which can be electrically turned OFF (22) or disconnected as desired, by application of an electrical pulse. Microswitch structures (10) constitute the thin film element, contacted by a pair of separate electrodes (16a, 16b) and have a finite, pre-selected ON resistance which is ideally suited, for example, as a programmable binary synaptic connection for electronic implementation of neural network architectures. The MnO.sub.2-x microswitch is non-volatile, patternable, insensitive to ultraviolet light, and adherent to a variety of insulating substrates (14), such as glass and silicon dioxide-coated silicon substrates.

  8. Thin-Film Transistors and Circuits Based on Carbon Nanotubes

    Microsoft Academic Search

    Didier Pribat; P. Bondavalli

    2012-01-01

    Carbon nanotubes are actively studied for thin-film transistor and electronics applications. Although these nanomaterials were first considered as potential candidates for the replacement of Si MOS type transistors in VLSI circuits, their main field of application is shifting towards large area electronics on flexible, plastic-type substrates, a domain which is at present, less demanding in terms of device dimensions and

  9. Photostable solar concentrators based on fluorescent glass films

    Microsoft Academic Search

    Renata Reisfeld; Dimitri Shamrakov; Christian Jorgensen

    1994-01-01

    Efficient luminescent solar concentrators (LSC) were prepared by deposition of organi- cally modified sol-gel films doped by photostable perylimide dyes on plexiglas substrates. The absorption spectra of these dyes extends from 420 to 620 nm covering the visible part of the solar spectrum and the emission is between 550 and 750 nm, close to the optimum response of silicon and

  10. Formation of thin film Tl-based high-Tc? superconducting oxides from amorphous alloy precursors 

    E-print Network

    Williams, John Charles

    1991-01-01

    -based thin film superconductors. The most popular deposition method seems to be through the use of sputter techniques. IS SO 31 32 33 Sputter deposition methods have been used to produce nearly single-phase 2212 films with a T, near 100 K1s 3o 3~ 32 ss... highly oriented 2021 and 2212 phase films. 4S 44 Hermann et aL reports using two different techniques. 4s One technique uses either magnetron sputtering or laser ablation of Ba-Ca-Cu oxides onto various substrates. Thallium vapor diffusion...

  11. Interfacial properties of lignin-based electrospun nanofibers and films reinforced with cellulose nanocrystals.

    PubMed

    Ago, Mariko; Jakes, Joseph E; Johansson, Leena-Sisko; Park, Sunkyu; Rojas, Orlando J

    2012-12-01

    Sub-100 nm resolution local thermal analysis, X-ray photoelectron spectroscopy (XPS), and water contact angle (WCA) measurements were used to relate surface polymer distribution with the composition of electrospun fiber mats and spin coated films obtained from aqueous dispersions of lignin, polyvinyl alcohol (PVA), and cellulose nanocrystal (CNC). Defect-free lignin/PVA fibers were produced with radii which were observed to increase with lignin concentration and with the addition of CNCs. XPS and WCA results indicate a nonlinear relationship between the surface and the bulk compositions. A threshold around 50 wt % bulk composition was identified in which extensive partitioning of PVA and lignin components occurred on the surface below and above this value. In 75:25 wt % lignin/PVA solvent cast films, phase separated domains were observed. Using nanoscale thermal analyses, the continuous phase was determined to be lignin-rich and the discontinuous phase had a lignin/PVA dispersion. Importantly, the size of the phase separated domains was reduced by the addition of CNCs. When electrospun fiber surfaces were lignin-rich, the addition of CNCs affected their surfaces. In contrast, no surface effects were observed with the addition of CNCs in PVA-rich fibers. Overall, we highlight the importance of molecular interactions and phase separation on the surface properties of fibers from lignin as an abundant raw material for the fabrication of new functional materials. PMID:23186246

  12. Reactive coating of soybean oil-based polymer on nanofibrillated cellulose film for water vapor barrier packaging.

    PubMed

    Lu, Peng; Xiao, Huining; Zhang, Weiwei; Gong, Glen

    2014-10-13

    Nanofibrillated cellulose (NFC) easily forms a high strength film but is unable to withstand the influence of water vapor when used in high moisture situations. The water vapor transmission rate (WVTR) of a NFC film was as high as 5088 g/m(2)24h (38 °C, 90% RH). The addition of beeswax latex in a NFC casting film (NFX) lowered the WVTR to 3918 g/m(2)24h. To further reduce the WVTR, a coating agent comprised of acrylated epoxidized soybean oil (AESO) and 3-aminopropyltriethoxysilane (APTS) was applied onto the NFX film using a rod coater. A combination of the suitable AESO/APTS ratio, initiator dosing, curing time and temperature could reduce the WVTR to 188 g/m(2) 24h when the coat weight was 5 g/m(2). Moreover, the coated NFX film was highly hydrophobic along with the improved transparency and thermal stability. This biodegradable polymer-coated NFC film can be used as potential packaging barrier in certain areas. PMID:25037383

  13. Rheological properties of pullulan-sodium alginate based solutions during film formation.

    PubMed

    Xiao, Qian; Tong, Qunyi; Zhou, Yujia; Deng, Fangming

    2015-10-01

    During film formation, the rheological properties of pullulan, sodium alginate, and blends, dried at 50°C were studied using an oscillatory rheometer. According to the drying curves, the drying process of pullulan, alginate, and blend films was divided into three stages. At the first drying stage, four samples exhibited typical liquid-like viscoelastic behavior. As the drying proceeded (polysaccharide concentration up to 75%), pure pullulan chains formed an entangled network, whereas coupling of alginate molecules gave a weak gel. At this drying stage, complex viscosity data for 75% alginate and blends were fitted with the power law equation. The effects of drying on the mechanical properties of pullulan-sodium alginate based samples were analyzed using the generalized Maxwell model, and their relaxation spectra were determined. The rheological properties during drying obtained from this study is essential for understanding film-forming mechanism and predicting the properties of pullulan-sodium alginate based edible films. PMID:26076600

  14. The mechanisms of plant stress mitigation by kaolin-based particle films and its applications in horticultural and agricultural crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Kaolin-based particle films have utility in reducing insect, heat, light, and uv stress in plants due to the reflective nature of the particles. Particle films with a residue density of 1 to 3 g/ square meter have been evaluated in a range of crops and agricultural environments. The particle film ...

  15. Fabrication of highly dielectric nano-BaTiO3\\/epoxy-resin composite plate having trenches by mold casting and its application to capacitive energy harvesting

    Microsoft Academic Search

    M. Suzuki; N. Matsushita; T. Hirata; R. Yoneya; J. Onishi; T. Wada; T. Takahashi; T. Nishida; Y. Yoshikawa; S. Aoyagi

    2011-01-01

    We propose a fabrication method of dielectric plate having trenches, in which a composite material of nano-BaTiO3 particles and epoxy-resin is casted into a mold of patterned thick photosensitive dry film. The features are, 1) the relative dielectric constant ? r is a dozen, which is no less than those of other polymer-based ferroelectric such as poly-vinylidene-difluoride (PVDF), 2) fabrication

  16. The potential of centrifugal casting for the production of near net shape uranium parts

    SciTech Connect

    Robertson, E. [United States Air Force Academy, Colorado Springs, CO (US). Dept. of Engineering Mechanics

    1993-09-01

    This report was written to provide a detailed summary of a literature survey on the near net shape casting process of centrifugal casting. Centrifugal casting is one potential casting method which could satisfy the requirements of the LANL program titled Near Net Shape Casting of Uranium for Reduced Environmental, Safety and Health Impact. In this report, centrifugal casting techniques are reviewed and an assessment of the ability to achieve the near net shape and waste minimization goals of the LANL program by using these techniques is made. Based upon the literature reviewed, it is concluded that if properly modified for operation within a vacuum, vertical or horizontal centrifugation could be used to safely cast uranium for the production of hollow, cylindrical parts. However, for the production of components of geometries other than hollow tubes, vertical centrifugation could be combined with other casting methods such as semi-permanent mold or investment casting.

  17. Electrochemical synthesis and characterization of nanorods, nanocolumnar ceria – based thin films on different glass substrates

    Microsoft Academic Search

    L. ?erovi?; V. Lair; O. Lupan; M. Cassir; A. Ringuedé

    2010-01-01

    Nanorods, nanocolumnar-based ceria thin films were electrodeposited onto (FTO) or (ITO) glass substrates, at room temperature. Cubic fluorite type ceria nanostructured films of high crystal quality were synthesized on both substrates, as confirmed by X-ray diffraction and Raman spectroscopy. It was found that a substrate is a structure-directing agent for the growth process of ceria. Columnar-like particles were grown on

  18. Martensitic transformation and shape memory behavior in sputter-deposited TiNi-base thin films

    Microsoft Academic Search

    S Miyazaki; A Ishida

    1999-01-01

    Since 1990, Ti?Ni and Ti?Ni?X (X=Cu, Pd, Hf) thin films have been made by sputtering. The motivation for fabricating sputter-deposited TiNi-base shape memory alloy thin films originates from the great demand for the development of powerful microactuators which can drive micromachines, because actuation force and displacement are greatest in shape memory alloys amongst many actuator materials. Stable shape memory effect

  19. Oxidation kinetics of Ni metallic films: Formation of NiO-based resistive switching structures

    Microsoft Academic Search

    L. Courtade; Ch. Turquat; Ch. Muller; J. G. Lisoni; L. Goux; D. J. Wouters; D. Goguenheim; P. Roussel; L. Ortega

    2008-01-01

    Resistive switching controlled by external voltage has been reported in many Metal\\/Resistive oxide\\/Metal (MRM) structures in which the resistive oxide was simple transition metal oxide thin films such as NiO or TiO2 deposited by reactive sputtering. In this paper, we have explored the possibility to form NiO-based MRM structures from the partial oxidation of a blanket Ni metallic film using

  20. A photoelectrochemical solar cell based on ZnO\\/dye\\/polypyrrole film electrode as photoanode

    Microsoft Academic Search

    Yanzhong Hao; Maizhi Yang; Weihua Li; Xuebin Qiao; Li Zhang; Shengmin Cai

    2000-01-01

    Nanostructured ZnO film electrodes were prepared. A preliminary PEC solar cell based on nanostructured Zno\\/dye\\/polypyrrole (PPy) film electrode was fabricated. A fill factor of 0.754 and a high overall light to electricity conversion efficiency of 1.3% for this PEC solar cell were obtained. The sensitization mechanisms of the nanostructured ZnO electrodes were also discussed.

  1. Dual-mode surface-plasmon sensor based on bimetallic film.

    PubMed

    Dyankov, G; Zekriti, M; Bousmina, M

    2012-05-01

    We propose a plasmonic structure, based on a silver-gold two-layered metallic film, where two surface plasmons (SPs) with equal propagation constants are excited simultaneously at different wavelengths. We show theoretically that the bimetallic film provides unique opportunities for manipulation of plasmons and optimization of the accuracy and cross-sensitivity. The structure can be used as an effective self-reference SP sensor in wavelength-interrogated design. PMID:22614425

  2. THE FUTURE DEVELOPMENT OF ENERGETIC THIN-FILM PROCESSES FOR SPACED BASED DEPOSITIONS

    Microsoft Academic Search

    Michael L. Fulton

    NASA's Lunar-Mars proposal (January 14, 2004) plans to use the Moon as an outpost for future voyages to Mars and beyond. The ability to deposit high performance thin-film coatings in the vacuum of lunar-space will be extremely valuable for executing many aspects of this new mission. Space-based thin-film depositions will enable the future development of flexible large- area space antennae

  3. Growth and investigation of p-n structures based on Fe3O4thin films

    Microsoft Academic Search

    K. Sliuziene; V. Lisauskas; R. Butkute; B. Vengalis; S. Tamulevicius; M. Andrulevicius

    2008-01-01

    We report preparation and investigation of p-n heterostructures based on Fe3O4 thin films grown on n-Si(111) substrates as well as indium oxide (IO) and tin doped indium oxide (ITO) layers deposited on lattice-matched monocrystalline ZrO2:Y2O3(100). Thin Fe3O4 films with thickness ranging from 100 to 300 nm were grown in situ at 400 K using dc magnetron sputtering technique. The measurement

  4. Sol-Gel Synthesis of Vanadate-Based Thin Films as Counter Electrodes in Electrochromic Devices

    Microsoft Academic Search

    Riccardo Ceccato; Giovanni Carturan; Franco Decker; Florinda Artuso

    2003-01-01

    V2O5-based thin films were prepared via the sol-gel method in order to obtain semiconductive films suitable as counter electrodes in electrochemical devices (e.g. electrochromic windows). Different metal precursors (nickel 2,4-pentanedionate, NiCl2, BiCl3, SbCl3) were added, after dissolution, into the starting vanadium oxo-triisopropoxide solution in the presence of acetic acid as a chelating agent. Preventing different synthesis conditions due to the

  5. Effect of third-element additions on properties of Co-Cr-based films

    Microsoft Academic Search

    Masayuki Sagoi; Tetsuo Inoue

    1990-01-01

    The fundamental effects of adding several elements to the Co-Cr system on the properties of Co-Cr-based films were extensively investigated. Tantalum, molybdenum, vanadium, and rhenium were chosen as the additives. A large amount of each element was added to a Co–17-at. % Cr film. Ta addition improved the squareness and suppressed the in-plane coercive force without lowering the perpendicular coercive

  6. Investigation of ferroelectric multilayer structures with properties of multiferroics based on barium-strontium titanate films

    NASA Astrophysics Data System (ADS)

    Semenov, A. A.; Dedyk, A. I.; Myl'nikov, I. L.; Pakhomov, O. V.; Bogachev, Yu. V.; Knyazev, M. N.; Pavlova, Yu. V.; Belyavskii, P. Yu.

    2015-03-01

    The results of investigations of the dielectric, magnetic, and structural properties of films with multiferroic properties have been presented. Two methods of the formation of multiferroic media have been analyzed: the method based on the formation of multilayer structures containing ferroelectric and ferromagnetic films and the method of introducing magnetic elements into a ferroelectric material in concentrations sufficient to induce magnetic properties in the composite material.

  7. Preparation and characterization of agar/clay nanocomposite films: the effect of clay type.

    PubMed

    Rhim, Jong-Whan; Lee, Soo-Bin; Hong, Seok-In

    2011-04-01

    Agar-based nanocomposite films with different types of nanoclays, such as Cloisite Na+, Cloisite 30B, and Cloisite 20A, were prepared using a solvent casting method, and their tensile, water vapor barrier, and antimicrobial properties were tested. Tensile strength (TS), elongation at break (E), and water vapor permeability (WVP) of control agar film were 29.7±1.7 MPa, 45.3±9.6%, and (2.22±0.19)×10(-9) g·m/m2·s·Pa, respectively. All the film properties tested, including transmittance, tensile properties, WVP, and X-ray diffraction patterns, indicated that Cloisite Na+ was the most compatible with agar matrix. TS of the nanocomposite films prepared with 5% Cloisite Na+ increased by 18%, while WVP of the nanocomposite films decreased by 24% through nanoclay compounding. Among the agar/clay nanocomposite films tested, only agar/Cloisite 30B nanocomposite film showed a bacteriostatic function against?Listeria monocytogenes. PMID:21535851

  8. Centrifugal precision cast TiAl turbocharger wheel using ceramic mold

    Microsoft Academic Search

    Wang Shouren; Guo Peiquan; Yang Liying

    2008-01-01

    It is the potential candidate for gamma TiAl-based alloys that would replace Ni-based superalloys, which are being used in fabrication of the turbocharger wheel currently. Cast Ti–47Al–2Cr–2Nb alloys due to their specific performance requirement are now on the verge of a commercial application. A novel precision casting technique, which combines the ceramic mold casting with centrifugal casting, was described in

  9. Understanding the distribution of natural wax in starch-wax films using synchrotron-based FTIR (S-FTIR).

    PubMed

    Muscat, Delina; Tobin, Mark J; Guo, Qipeng; Adhikari, Benu

    2014-02-15

    High amylose starch-glycerol (HAG) films were produced incorporating beeswax, candelilla wax and carnauba wax in the presence and absence of Tween-80 in order to determine the distribution of wax in the films during the film formation process. The distribution of these waxes within the film was studied using Synchrotron based Fourier Transform Infrared Spectroscopy (S-FTIR) which provided 2D mapping along the thickness of the film. The incorporation of 5% and 10% wax in HAG films produced randomly distributed wax or wax-rich domains, respectively, within these films. Consequently, the addition of these waxes to HAG increased the surface roughness and hydrophobicity of these films. The addition of Tween-80 caused variations in wax-rich bands within the films. The HAG+carnauba wax+Tween-80 films exhibited domed wax-rich domains displayed with high integrated CH2 absorption value at the interior of the films, rougher surface and higher contact angle values than the other films. The S-FTIR 2D images indicated that the distribution of wax in starch-wax films correlated with the roughness and hydrophobicity of the starch-wax films. PMID:24507264

  10. Correlation between macroscopic porosity location and liquid metal pressure in centrifugal casting technique.

    PubMed

    Vaidyanathan, T K; Schulman, A; Nielsen, J P; Shalita, S

    1981-01-01

    Radiographic analysis of uniform cylindrical castings fabricated by the centrifugal casting technique has revealed that the macroscopic porosity is dependent on the location of the sprue attachment to the casting. This is attributed to the significant pressure gradient associated with the centrifugal casting technique. The pressure gradient results in different heat transfer rates at portions of the castings near and away from the free surface of the button. Consequently, the macroscopic porosity is invariably at portions of the casting close to the free surface of the button. In addition, some optimized sprue-reservoir combinations could be predicted and proved, based on this pressure gradient concept. PMID:7002971

  11. ACCURATE QUANTIFICATION OF DRIED RESIDUE THIN FILMS USING X-RAY FLUORESCENCE

    SciTech Connect

    C. WORLEY; G. HAVRILLA

    2000-09-01

    An XRF specimen preparation method was developed to quantify the concentration of gallium in plutonium metal while minimizing the risk of contaminating the instrument with radioactive material. To ensure that homogeneous specimens are examined, plutonium is dissolved in dilute HCl and HNO{sub 3} prior to analysis. In the preliminary work here, non-radioactive aqueous gallium standards were prepared, and zinc was added as an internal standard to improve the accuracy and precision. Aliquots from these solutions were cast on Mylar XRF films and air dried prior to analysis. Two methods of casting the solutions were evaluated: (1) casting as a thin layer using a surfactant to wet the support film and (2) casting multiple small spots on the support film. Aqueous gallium standards were prepared and cast as dried residue specimens using each method. These specimens were then analyzed, and calibration curves were prepared. Highly linear calibrations were obtained for each preparation method when zinc was used as the internal standard (RMS values {le}1% of the standards concentration range in both cases). Based on this preliminary work, this dried residue process appears very promising for the accurate quantification of gallium in plutonium.

  12. Hickey, C8206_all casts Hickey, C8206_all casts, page 1

    E-print Network

    Hickey, Barbara

    Hickey, C8206_all casts Hickey, C8206_all casts, page 1 #12;Hickey, C8206_all casts Hickey, C8206_all casts, page 2 #12;Hickey, C8206_all casts Hickey, C8206_all casts, page 3 #12;Hickey, C8206_all casts Hickey, C8206_all casts, page 4 #12;Hickey, C8206_all casts Hickey, C8206_all casts, page 5 #12

  13. Informing Selection of Nanomaterial Concentrations for ToxCast In Vitro Testing based on Occupational Exposure Potential

    EPA Science Inventory

    Little justification is generally provided for selection of in vitro assay testing concentrations for engineered nanomaterials (ENMs). Selection of concentration levels for hazard evaluation based on real-world exposure scenarios is desirable. We reviewed published ENM concentr...

  14. Characterization of constitutional liquid film migration in nickel-base alloy 718

    SciTech Connect

    Acoff, V.L.; Thompson, R.G. [Univ. of Alabama, Birmingham, AL (United States)

    1996-09-01

    When multiphase alloys are rapidly heated, it is possible to cause melting of the interface between phases. This is called constitutional liquation if, during melting, the bulk composition is in a nonliquid region of the phase diagram but the tie-line between the liquating phases passes through a liquid region. The liquid produced during constitutional liquation can spread along grain boundaries and promote liquid film migration (LFM). This is known as constitutional liquid film migration (CLFM), which is thermodynamically similar to liquid film migration; however, mechanistically there are significant differences. Nickel-base alloy 718 has been studied to show the features of migration that are unique to CLFM. Experimentation consisted of heat-treating rods of alloy 718 to promote the trapping of niobium carbide particles on the grain boundaries. These samples were then subjected to isothermal treatments above their constitutional-liquation temperature, which produced CLFM of the grain boundaries. The movement of the liquid films away from their centers of curvature, the formation of a new solid solution behind the migrated liquid films, and the reversals of curvature of the migrated liquid films confirmed that CLFM was the phenomenon observed. The concentration of niobium behind the migrated liquid films for isothermal treatments below the solidus temperature was shown to be greater than the niobium concentration in the matrix. Above the solidus temperature, there was no increase in niobium concentration. The validity of the coherency strain hypothesis as the driving force for CLFM in alloy 718 is discussed.

  15. Technologies for thin film CIGS-based photovoltaics

    SciTech Connect

    Britt, J.S.; Delahoy, A.E.; Kiss, Z.J. [Energy Photovoltaics, Inc., 276 Bakers Basin Road, Lawrenceville, New Jersey 08648 (United States)

    1997-02-01

    This paper reviews EPV{close_quote}s approach to CIGS formation by a hybrid of sputtering and evaporation processes, and describes a differential thermometry technique for performing time progressive reaction studies of the absorber formation process. Investigations of alternative window processes to replace CdS, the DC reactive sputtering of ZnO films, and recent module results are also discussed. {copyright} {ital 1997 American Institute of Physics.}

  16. Mimetic marine antifouling films based on fluorine-containing polymethacrylates

    NASA Astrophysics Data System (ADS)

    Sun, Qianhui; Li, Hongqi; Xian, Chunying; Yang, Yihang; Song, Yanxi; Cong, Peihong

    2015-07-01

    Novel methacrylate copolymers containing catechol and trifluoromethyl pendant side groups were synthesized by free radical polymerization of N-(3,4-dihydroxyphenyl)ethyl methacrylamide (DMA) and 2,2,2-trifluoroethyl methacrylate (TFME) with ?,??-azobisisobutyronitrile (AIBN) as initiator. A series of copolymers with different content of TFME ranging from 3% to 95% were obtained by changing the molar ratio of DMA to TFME from 25:1 to 1:25. Fourier transform infrared (FT-IR) spectroscopy, gel permeation chromatography (GPC), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were used to characterize the copolymers, which displayed a certain degree of hardness and outstanding thermostability reflected from their high glass transition temperatures. The copolymers could adhere to surfaces of glass, plastics and metals due to introduction of catechol groups as multivalent hydrogen bonding anchors. Water contact angle on the polymer films was up to 117.4°. Chemicals resistance test manifested that the polymer films possessed excellent resistance to water, salt, acid and alkali. Moreover, the polymer films displayed fair antifouling property and might be used as promising environmentally friendly marine antifouling coatings.

  17. Synthesis, structure, and tribological behavior of nanocomposite DLC based thin films

    NASA Astrophysics Data System (ADS)

    Singh, Varshni

    Diamond-like carbon (DLC) films possess a combination of attractive properties and have been largely employed to modify the tribological behavior of materials. Nanocomposite, metal-containing DLC films are the new generation of these coatings providing tremendous potential to modify and tailor their properties expanding their applications in the field of nanotechnology. The present study investigates nanoscale effects on the tribological behavior of composite nanostructured DLC-based films and functional coatings. Three aspects were studied: (i) effect of Cr interlayer on a functionally gradient substrate; (ii) nanoparticulate Cr-containing DLC (Cr-DLC) films; and (iii) nanocomposite multilayered Cr/DLC coatings. Intensified plasma assisted nitriding produced a functionally graded interface and Cr layers exhibited best tribological behavior in their presence validating the theoretical concept. Nanocomposite Cr-DLC films were synthesized with Cr content in the range of about 0.1 at% to about 17 at%, on Si 100 substrate. TEM studies showed defect free, dense and continuous film containing crystalline nanoclusters embedded in amorphous matrix. X-ray absorption spectroscopy showed that the chemical state and environment around Cr in films with ?1.5 at% Cr is similar to that in Cr-carbide. However, the environment around Cr in films with Cr ? 0.4 at% is distinctly different with atomic clusters of Cr dissolved in the DLC matrix. Nanoindentation experiments showed that Cr-DLC films possess high hardness. Also, Cr-DLC films exhibit low friction (up to 12 at% Cr) and excellent wear resistance (up to ˜5 at% Cr) with a low stable wear rate (10-7 mm3 /N-m). In the multilayered nanocomposite films, DLC layers were found to be amorphous whereas Cr layers exhibit a nanocrystalline structure. Cr/DLC interfaces were found to be dense and continuous. Presence of DLC and a decrease of Cr layer thickness increases the hardness. This behavior was found to be consistent with the Hall-Petch formalism. Multilayered nanocomposite films with a significant volume fraction of DLC were found to possess low friction and low wear rate (10-7 mm3/N-m). A common wear mechanism was found on both nanocomposite and multilayered systems. These nanocomposite and multilayered systems exhibited wear and friction properties comparable to those of DLC films, thereby expanding their scope in the field of nanotechnology.

  18. The Lazy Sweep Ray Casting Algorithm for Rendering Irregular Grids

    Microsoft Academic Search

    Cláudio T. Silva; Joseph S. B. Mitchell

    1997-01-01

    Lazy Sweep Ray Casting is a fast algorithm for rendering general irregular grids. It is based on the sweep-plane paradigm, and it is able to accelerate ray casting for rendering irregular grids, including disconnected and nonconvex (even with holes) unstructured irregular grids with a rendering cost that decreases as the \\

  19. Learning and Removing Cast Shadows through a Multidistribution Approach

    Microsoft Academic Search

    Nicolas Martel-brisson; André Zaccarin

    2007-01-01

    Moving cast shadows are a major concern for foreground detection algorithms. The processing of foreground images in surveillance applications typically requires that such shadows be identified and removed from the detected foreground. This paper presents a novel pixel-based statistical approach to model moving cast shadows of nonuniform and varying intensity. This approach uses the Gaussian mixture model (GMM) learning ability

  20. Moving Cast Shadow Detection from a Gaussian Mixture Shadow Model

    Microsoft Academic Search

    Nicolas Martel-brisson; André Zaccarin

    2005-01-01

    Moving cast shadows are a major concern for foreground detection algorithms. Processing of foreground images in surveillance applications typically requires that such shadows have been identified and removed from the detected foreground. This paper presents a novel pixel-based statistical approach to model moving cast shadows of non-uniform and varying intensity. This approach uses the Gaussian mixture model (GMM) learning ability

  1. CAST FLOOR WITH VIEW OF TORPEDO LADLE (BENEATH CAST FLOOR) ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    CAST FLOOR WITH VIEW OF TORPEDO LADLE (BENEATH CAST FLOOR) AND KEEPERS OF THE CAST HOUSE FLOOR, S.L. KIMBROUGH AND DAVID HOLMES. - U.S. Steel, Fairfield Works, Blast Furnace No. 8, North of Valley Road, West of Ensley-Pleasant Grove Road, Fairfield, Jefferson County, AL

  2. Methodology for cost analysis of film-based and filmless portable chest systems

    NASA Astrophysics Data System (ADS)

    Melson, David L.; Gauvain, Karen M.; Beardslee, Brian M.; Kraitsik, Michael J.; Burton, Larry; Blaine, G. James; Brink, Gary S.

    1996-05-01

    Many studies analyzing the costs of film-based and filmless radiology have focused on multi- modality, hospital-wide solutions. Yet due to the enormous cost of converting an entire large radiology department or hospital to a filmless environment all at once, institutions often choose to eliminate film one area at a time. Narrowing the focus of cost-analysis may be useful in making such decisions. This presentation will outline a methodology for analyzing the cost per exam of film-based and filmless solutions for providing portable chest exams to Intensive Care Units (ICUs). The methodology, unlike most in the literature, is based on parallel data collection from existing filmless and film-based ICUs, and is currently being utilized at our institution. Direct costs, taken from the perspective of the hospital, for portable computed radiography chest exams in one filmless and two film-based ICUs are identified. The major cost components are labor, equipment, materials, and storage. Methods for gathering and analyzing each of the cost components are discussed, including FTE-based and time-based labor analysis, incorporation of equipment depreciation, lease, and maintenance costs, and estimation of materials costs. Extrapolation of data from three ICUs to model hypothetical, hospital-wide film-based and filmless ICU imaging systems is described. Performance of sensitivity analysis on the filmless model to assess the impact of anticipated reductions in specific labor, equipment, and archiving costs is detailed. A number of indirect costs, which are not explicitly included in the analysis, are identified and discussed.

  3. Finite element modeling of the deformation of magnetoelastic film

    SciTech Connect

    Barham, Matthew I. [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94551 (United States); White, Daniel A., E-mail: white37@llnl.go [Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA 94551 (United States); Steigmann, David J. [6133 Etcheverry Hall, University of California, Berkeley, CA 94720 (United States)

    2010-09-01

    Recently a new class of biocompatible elastic polymers loaded with small ferrous particles, a magnetoelastic polymer, has been developed. This engineered material is formed into a thin film using spin casting. An applied magnetic field will deform the film. The magnetic deformation of this film has many possible applications, particularly in microfluidic pumps and pressure regulators. In this paper a finite element method suitable for the transient simulation of arbitrarily shaped three-dimensional magnetoelastic polymers subjected to time-varying magnetic fields is developed. The approach is similar to that employed in finite elment magnetohydrodynamic simulations, the key difference is a more complex hyperelastic material model. In order to confirm the validity of the approach, finite element solutions for an axially symmetric thin film are compared to an analytical solution based on the membrane (infinitely thin) approximation. For this particular problem the two approaches give qualitatively similar results and converge as the film thickness approaches zero.

  4. Sealing micropores in thin castings

    NASA Technical Reports Server (NTRS)

    Mersereau, G. A.; Nitzschke, G. O.; Ochs, H. L.; Sutch, F. S.

    1981-01-01

    Microscopic pores in thin-walled aluminum castings are sealed by impregnation pretreatment. Technique was developed for investment castings used in hermetically sealed chassic for electronic circuitry. Excessively high leakage rates were previously measured in some chassis.

  5. Numerical study of porosity in titanium dental castings.

    PubMed

    Wu, M; Sahm, P R; Augthun, M; Spiekermann, H; Schädlich-Stubenrauch, J

    1999-09-01

    A commercial software package, MAGMASOFT (MAGMA Giessereitechnologie GmbH, Aachen, Germany), was used to study shrinkage and gas porosity in titanium dental castings. A geometrical model for two simplified tooth crowns connected by a connector bar was created. Both mold filling and solidification of this casting model were numerically simulated. Shrinkage porosity was quantitatively predicted by means of a built-in feeding criterion. The risk of gas pore formation was investigated using the numerical filling and solidification results. The results of the numerical simulations were compared with experiments, which were carried out on a centrifugal casting machine with an investment block mold. The block mold was made of SiO2 based slurry with a 1 mm thick Zr2 face coat to reduce metal-mold reactions. Both melting and casting were carried out under protective argon (40 kPa). The finished castings were sectioned and the shrinkage porosity determined. The experimentally determined shrinkage porosity coincided with the predicted numerical simulation results. No apparent gas porosity was found in these model castings. Several running and gating systems for the above model casting were numerically simulated. An optimized running and gating system design was then experimentally cast, which resulted in porosity-free castings. PMID:15348102

  6. Apple peel-based edible film development using a high-pressure homogenization.

    PubMed

    Sablani, Shyam S; Dasse, Florian; Bastarrachea, Luis; Dhawan, Sumeet; Hendrix, Kathleen M; Min, Sea C

    2009-09-01

    Biopolymer films were developed from apple peels of apple process co-products and their physical properties were determined. Apple peel-based films with glycerol (23%, 33%, and 44%[w/w, dry basis]) were prepared using high-pressure homogenization (HPH) at different levels of pressure (138, 172, and 207 MPa). An evaluation of the rheological properties (elastic modulus [G'], viscous modulus [G''], and viscosity) of the film-forming solutions was performed. For the apple peel films, the water sorption isotherms, the kinetics of water absorption, the water vapor permeability (WVP), the oxygen permeability (OP), and the tensile properties were determined. The G' and viscosity of the film-forming solutions decreased significantly with increasing processing pressure (P < 0.05). However, no difference was observed in G'' values at different homogenization pressures (P > 0.05). The viscosity decreased from 644 to 468 kPa.s as the pressure increased from 138 to 207 MPa at 90 degrees C. The monolayer water content of the apple peel films decreased with increasing content of glycerol from 23% to 33%. Further increase in glycerol content did not change the monolayer water content. The water diffusion coefficient of the films was highest at the intermediate level of glycerol content. The barrier properties (WVP and OP) of the films increased with increasing level of glycerol, while processing pressure did not influence the gas barrier properties. The films prepared at 207 MPa were less stiff and strong, but more stretchable than those prepared at 138 and 172 MPa. PMID:19895466

  7. Affective Realism of Animated Films in the Development of Simulation-Based Tutoring Systems

    ERIC Educational Resources Information Center

    Ekanayake, Hiran B.; Fors, Uno; Ramberg, Robert; Ziemke, Tom; Backlund, Per; Hewagamage, Kamalanath P.

    2013-01-01

    This paper presents a study focused on comparing real actors based scenarios and animated characters based scenarios with respect to their similarity in evoking psychophysiological activity for certain events by measuring galvanic skin response (GSR). In the experiment, one group (n = 11) watched the real actors' film whereas another group (n…

  8. Recent progress in carbon nanotube-based flexible transparent conducting film

    NASA Astrophysics Data System (ADS)

    Geng, Hong-Zhang; Kim, Ki Kang; Lee, Young Hee

    2008-08-01

    Flexible transparent conducting films (TCFs) were fabricated on a PET substrate by various methods using carbon nanotubes dispersed in organic or water-based solution. Thin multi-walled carbon nanotubes, double-walled carbon nanotubes, and single-walled carbon nanotubes were used to compare the performance for TCFs. Optimal design rules for types of nanotubes, surfactants, the degree of dispersion, and film preparation methods were discussed. The TCFs were characterized by scanning electron microscopy, TGA, Raman, optical absorption spectra, and sheet resistance. The dispersion of CNTs in water and in bisolvent has been tried. A simple acid treatment on the TCF film increased the conductivity by about four times. Doping and functionalization techniques will be further introduced to improve the conductivity of the film.

  9. Casting Of Multilayer Ceramic Tapes

    NASA Technical Reports Server (NTRS)

    Collins, Earl R., Jr.

    1991-01-01

    Procedure for casting thin, multilayer ceramic membranes, commonly called tapes, involves centrifugal casting at accelerations of 1,800 to 2,000 times normal gravitational acceleration. Layers of tape cast one at a time on top of any previous layer or layers. Each layer cast from slurry of ground ceramic suspended in mixture of solvents, binders, and other components. Used in capacitors, fuel cells, and electrolytic separation of oxygen from air.

  10. Rapid casting solutions: a review

    Microsoft Academic Search

    Munish Chhabra; Rupinder Singh

    2011-01-01

    Purpose – This paper seeks to review the industrial applications of state-of-the-art additive manufacturing (AM) techniques in metal casting technology. An extensive survey of concepts, techniques, approaches and suitability of various commercialised rapid casting (RC) solutions with traditional casting methods is presented. Design\\/methodology\\/approach – The tooling required for producing metal casting such as fabrication of patterns, cores and moulds with

  11. An energy landscape based approach for studying supercooled liquid and glassy thin films

    NASA Astrophysics Data System (ADS)

    Shah, Pooja; Mittal, Jeetain; Truskett, Thomas M.

    2004-03-01

    Materials in confined spaces are important in science and technology. Examples include biological fluids in membranes, liquids trapped in porous rocks, and thin-film materials used in high-resolution patterning technologies. However, few reliable rules exist to predict how the properties of materials will be affected by thin-film confinement. We have recently shown that the potential energy landscape formalism can be used to study, by both theory [1] and simulation [2], how the behavior of thin-film materials depends on sample dimensions and film-substrate interactions. Our landscape-based mean-field theory [1] can be used to study both the thermodynamic properties and the ideal glass transition of thin films. It predicts that, in the case of neutral or repulsive walls, the ideal glass transition temperature is lowered by decreasing film thickness. This is in qualitative agreement with experimental trends for the kinetic glass transition in confined fluids. Landscape-based approaches are also valuable for understanding the structural and mechanical properties of thin-film glasses. We demonstrate how the concept of an "equation of state of the energy landscape" [3] can be generalized to thin films [1, 2], where it gives insights into potential molecular mechanisms of tensile strength. [1] T. M. Truskett and V. Ganesan, J. Chem. Phys. 119, 1897-1900(2003); J. Mittal, P. Shah and T. M. Truskett, to be submitted to Langmuir. [2] P. Shah and T. M. Truskett, to be submitted to J. Phys. Chem. B. [3] S. Sastry, P. G. Debenedetti and F. H. Stillinger, Phys. Rev. E 56, 5533 (1997)

  12. Enhancements in Magnesium Die Casting Impact Properties

    SciTech Connect

    David Schwam; John F. Wallace; Yulong Zhu; Srinath Viswanathan; Shafik Iskander

    2000-06-30

    The need to produce lighter components in transportation equipment is the main driver in the increasing demand for magnesium castings. In many automotive applications, components can be made of magnesium or aluminum. While being lighter, often times the magnesium parts have lower impact and fatigue properties than the aluminum. The main objective of this study was to identify potential improvements in the impact resistance of magnesium alloys. The most common magnesium alloys in automotive applications are AZ91D, AM50 and AM60. Accordingly, these alloys were selected as the main candidates for the study. Experimental quantities of these alloys were melted in an electrical furnace under a protective atmosphere comprising sulfur hexafluoride, carbon dioxide and dry air. The alloys were cast both in a permanent mold and in a UBE 315 Ton squeeze caster. Extensive evaluation of tensile, impact and fatigue properties was conducted at CWRU on permanent mold and squeeze cast test bars of AZ91, AM60 and AM50. Ultimate tensile strength values between 20ksi and 30ksi were obtained. The respective elongations varied between 25 and 115. the Charpy V-notch impact strength varied between 1.6 ft-lb and 5 ft-lb depending on the alloy and processing conditions. Preliminary bending fatigue evaluation indicates a fatigue limit of 11-12 ksi for AM50 and AM60. This is about 0.4 of the UTS, typical for these alloys. The microstructures of the cast specimens were investigated with optical and scanning electron microscopy. Concomitantly, a study of the fracture toughness in AM60 was conducted at ORNL as part of the study. The results are in line with values published in the literature and are representative of current state of the art in casting magnesium alloys. The experimental results confirm the strong relationship between aluminum content of the alloys and the mechanical properties, in particular the impact strength and the elongation. As the aluminum content increases from about 5% in AM50 to over 9% in AZ91, more of the intermetallic Mg17Al12 is formed in the microstructure. For instance, for 15 increase in the aluminum content from AM50 to AM60, the volume fraction of eutectic present in the microstructure increases by 35%! Eventually, the brittle Mg17Al12 compound forms an interconnected network that reduces ductility and impact resistance. The lower aluminum in AM50 and AM60 are therefore a desirable feature in applications that call for higher impact resistance. Further improvement in impact resistance depends on the processing condition of the casting. Sound castings without porosity and impurities will have better mechanical properties. Since magnesium oxidizes readily, good melting and metal transfer practices are essential. The liquid metal has to be protected from oxidation at all times and entrainment of oxide films in the casting needs to be prevented. In this regard, there is evidence that us of vacuum to evacuate air from the die casting cavity can improve the quality of the castings. Fast cooling rates, leading to smaller grain size are beneficial and promote superior mechanical properties. Micro-segregation and banding are two additional defect types often encountered in magnesium alloys, in particular in AZ91D. While difficult to eliminate, segregation can be minimized by careful thermal management of the dies and the shot sleeve. A major source of segregation is the premature solidification in the shot sleeve. The primary solid dendrites are carried into the casting and form a heterogeneous structure. Furthermore, during the shot, segregation banding can occur. The remedies for this kind of defects include a hotter shot sleeve, use of insulating coatings on the shot sleeve and a short lag time between pouring into the shot sleeve and the shot.

  13. Base-metal dental casting alloy biocompatibility assessment using a human-derived three-dimensional oral mucosal model

    Microsoft Academic Search

    E. L. McGinley; G. P. Moran; G. J. P. Fleming

    Nickel–chromium (Ni–Cr) alloys used in fixed prosthodontics have been associated with type IV Ni-induced hypersensitivity. We hypothesised that the full-thickness human-derived oral mucosa model employed for biocompatibility testing of base-metal dental alloys would provide insights into the mechanisms of Ni-induced toxicity. Primary oral keratinocytes and gingival fibroblasts were seeded onto Alloderm™ and maintained until full thickness was achieved prior to

  14. The fractography of casting alloys

    Microsoft Academic Search

    G POWELL

    1994-01-01

    Several types of casting alloys were fractured using various loading modes (uniaxial tension, bending, impact, and torsion, and cyclic stressing), and the corresponding mechanical properties were determined. The unetched and etched fracture surfaces and the microstructures were examined using conventional techniques. The types of casting alloys that were the subjects f these investigations include gray iron, ductile iron, cast steel,

  15. Comparison of photovoltaic performance of TiO2 nanoparticles based thin films via different routes

    NASA Astrophysics Data System (ADS)

    Ji, Yajun

    2015-11-01

    Well crystallized TiO2 nanoparticles were prepared by hydrothermal and sol-gel routes, respectively. The morphologies, structures, crystallinity and optical properties of resulted TiO2 nanoparticles-based thin films via the two methods were examined by field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD) and reflectance spectra. In addition, comparison of photovoltaic performance of TiO2 nanoparticles-based thin films by the two methods was performed. It is found that the maximum energy conversion efficiency of 4.06% was achieved based on the obtained electrode via hydrothermal, which is much better than that of the sol-gels route. The uniform film structure with improved dye absorption capability, increased diffused reflectance property and relatively low charge recombination rates for injected electrons are believed to be responsible to the superior photoelectrochemical properties of dye-sensitized solar cells (DSSC) via hydrothermal route.

  16. Thin Film Absorbers Based on Plasmonic Phase Resonances

    E-print Network

    Cui, Yanxia; Xu, Jun; He, Sailing; Fang, Nicholas X

    2010-01-01

    We demonstrate an efficient double-layer light absorber by exciting plasmonic phase resonances. We show that the addition of grooves can cause mode splitting of the plasmonic waveguide cavity modes and all the new resonant modes exhibit large absorptivity greater than 90%. Some of the generated absorption peaks have wide-angle characteristics. Furthermore, we find that the proposed structure is fairly insensitive to the alignment error between different layers. The proposed plasmonic nano-structure designs may have exciting potential applications in thin film solar cells, thermal emitters, novel infrared detectors, and highly sensitive bio-sensors.

  17. Energy harvesting MEMS device based on thin film piezoelectric cantilevers

    Microsoft Academic Search

    W. J. Choi; Y. Jeon; J.-H. Jeong; R. Sood; S. G. Kim

    2006-01-01

    A thin film lead zirconate titanate Pb(Zr,Ti)O3 (PZT), energy harvesting MEMS device is developed to enable self-supportive sensors for in-service integrity monitoring of\\u000a large social and environmental infrastructures at remote locations. It is designed to resonate at specific frequencies of\\u000a an external vibrational energy source, thereby creating electrical energy via the piezoelectric effect. Our cantilever device\\u000a has a PZT\\/SiNx bimorph

  18. Depth profiles and free volume in aircraft primer films

    NASA Astrophysics Data System (ADS)

    Van Horn, J. D.; Chen, H.; Jean, Y. C.; Zhang, W.; Jaworowski, M. R.

    2015-06-01

    Positron annihilation lifetime spectroscopy (PALS) and associated techniques provide non-destructive methods to study the free volume inside polymeric materials, and to study material characteristics over a depth profile. Cast free films of organic- or aqueous-based, non-chromated aerospace primers, when cured for about one week, had very different water vapour transport (through-plane) behaviour. In addition, both types of primer films showed strong anisotropic behaviour in in-plane versus through-plane water vapour transport rates. We report the differences between the organic- and aqueous-based aircraft primer films samples and their surface depth profiles. In bulk PALS measurements, an aged, organic-based film exhibited typical lifetimes and intensities for a particulate-containing polymer film on both faces. In contrast, aqueous-based films exhibited face oriented-dependent differences. In all aqueous- based samples, the I3 value of the back of the sample was smaller. The primer film samples were also evaluated with mono-energetic positron beam techniques to generate depth profile information. The heterogeneity in the samples was verified by Doppler broadening of energy spectroscopy (DBES). A model for the differences in the faces of the films, and their layered structure is discussed.

  19. Ohno continuous casting

    Microsoft Academic Search

    H. Soda; A. McLean; G. Motoyasu; A. Ohno

    1995-01-01

    Production of net-shape products directly from the liquid is an attractive manufacturing route for alloys that are difficult to process or that cannot be rolled, drawn, or extruded. Developed at the Chiba Institute of Technology in Japan, the Ohno Continuous Casting (OCC) approach not only provides significant cost savings, but also has the potential to create new products. OCC process

  20. Casting and Angling.

    ERIC Educational Resources Information Center

    Little, Mildred J.; Bunting, Camille

    The self-contained packet contains background information, lesson plans, 15 transparency and student handout masters, drills and games, 2 objective examinations, and references for teaching a 15-day unit on casting and angling to junior high and senior high school students, either as part of a regular physical education program or as a club…

  1. Casting and Angling.

    ERIC Educational Resources Information Center

    Smith, Julian W.

    As part of a series of books and pamphlets on outdoor education, this manual consists of easy-to-follow instructions for fishing activities dealing with casting and angling. The manual may be used as a part of the regular physical education program in schools and colleges or as a club activity for the accomplished weekend fisherman or the…

  2. The X-ray Telescope of CAST

    E-print Network

    M. Kuster; H. Bräuninger; S. Cébrian; M. Davenport; C. Elefteriadis; J. Englhauser; H. Fischer; J. Franz; P. Friedrich; R. Hartmann; F. H. Heinsius; D. H. H. Hoffmann; G. Hoffmeister; J. N. Joux; D. Kang; K. Königsmann; R. Kotthaus; T. Papaevangelou; C. Lasseur; A. Lippitsch; G. Lutz; J. Morales; A. Rodríguez; L. Strüder; J. Vogel; K. Zioutas

    2007-05-10

    The Cern Axion Solar Telescope (CAST) is in operation and taking data since 2003. The main objective of the CAST experiment is to search for a hypothetical pseudoscalar boson, the axion, which might be produced in the core of the sun. The basic physics process CAST is based on is the time inverted Primakoff effect, by which an axion can be converted into a detectable photon in an external electromagnetic field. The resulting X-ray photons are expected to be thermally distributed between 1 and 7 keV. The most sensitive detector system of CAST is a pn-CCD detector combined with a Wolter I type X-ray mirror system. With the X-ray telescope of CAST a background reduction of more than 2 orders off magnitude is achieved, such that for the first time the axion photon coupling constant g_agg can be probed beyond the best astrophysical constraints g_agg < 1 x 10^-10 GeV^-1.

  3. AlGaInN-based light emitting diodes with a transparent p-contact based on thin ITO films

    SciTech Connect

    Smirnova, I. P., E-mail: irina@quantum.ioffe.ru; Markov, L. K.; Pavlyuchenko, A. S. [Russian Academy of Sciences, Ioffe Physical Technical Institute (Russian Federation); Kukushkin, M. V. [ZAO Innovation Company 'TETIS' (Russian Federation)

    2012-03-15

    A method for obtaining transparent conductive ITO (indium-tin oxide) films aimed for use in light emitting diodes of the blue spectral range is developed. The peak external quantum efficiency of light-emitting diodes with a p-contact based on the obtained films reaches 25%, while for similar light-emitting diodes with a standard semitransparent metal contact, it is <10%. An observed increase in the direct voltage drop from 3.15 to 3.37 V does not significantly affect the possibility of applying these films in light-emitting diodes since the optical power of light-emitting diodes with a transparent p-contact based on ITO films exceeds that of chips with metal semitransparent p-contacts with a working current of 20 mA by a factor of almost 2.5. Light-emitting diodes with p-contacts based on ITO films successfully withstand a pumping current that exceeds their calculated working current by a factor of 5 without the appearance of any signs of degradation.

  4. Comparative Study of 3D Printing Technologies for Rapid Casting of Aluminium Alloy

    Microsoft Academic Search

    Simranpreet Singh Gill; Munish Kaplas

    2009-01-01

    The purpose of this study is to compare the efficacy of two rapid casting technologies, namely, ZCast process and investment casting based on 3D printing technique of rapid prototyping for casting of aluminium alloy. A standard procedure has been premeditated starting from the identification and design of benchmark. The concept was presented in physical form by producing prototypes to assess

  5. Converge-Cast with MIMO Luoyi Fu, Yi Qin, Xinbing Wang

    E-print Network

    Wang, Xinbing

    Converge-Cast with MIMO Luoyi Fu, Yi Qin, Xinbing Wang Dept. of Electronic Engineering Shanghai investigates throughput and delay based on a newly predominant traffic pattern, called converge-cast, where schemes under converge-cast for both static and mobile ad hoc networks (MANETs), respectively. In a static

  6. IMPROVEMENT OF CASTING PROCESS CONTROL BY COMPUTER SIMULATION AND EXPERIMENTAL OBSERVATION

    Microsoft Academic Search

    D. Kakas; L. Kovacevic; T. Pal

    The porosity is the most common defect in aluminum castings. As a consequence the porosity formation is very closely studied phenomenon. However vast majority of research is based on simple castings of little or no practical importance. The investi- gation described in this paper examined the porosity formation in the cast pistons which are suitable representatives of a complex shape

  7. Numerical optimization of gating system parameters for a magnesium alloy casting with multiple performance characteristics

    Microsoft Academic Search

    Zhizhong Sun; Henry Hu; Xiang Chen

    2008-01-01

    An optimization technique for design of gating system parameters of a cylindrical magnesium casting based on the Taguchi method with multiple performance characteristics was proposed in this paper. The various gating systems for a casting model of magnesium alloy were designed. Mold filling and solidification processes of the magnesium casting were simulated with the MAGMASOFT®. The simulation results indicated that

  8. A neural network system for the prediction of process parameters in pressure die casting

    Microsoft Academic Search

    Prasad K. D. V. Yarlagadda; Eric Cheng Wei Chiang

    1999-01-01

    In this work an artificial intelligent neural network system is developed to generate the process parameters for the pressure die casting process. The scope of this work includes analysing a physical model of the pressure die casting filling stage based on the governing equations of die cavity filling, and the collection of feasible casting data for the training of the

  9. Water-soluble single-walled carbon nanotubes films: Preparation, characterization and applications as electrochemical sensing films

    Microsoft Academic Search

    Chengguo Hu; Xiaoxia Chen; Shengshui Hu

    2006-01-01

    Water-soluble single-walled carbon nanotubes (SWNTs) were prepared via noncovalent functionalization by Congo red through a physical grinding treatment. Based on the unique property of strong rebundling when dried, water-soluble SWNTs were firmly immobilized on the surface of a glassy carbon electrode by a simple casting method. The prepared films were characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and

  10. Features of flexible transparent conducting films based on polyaniline-carbon nanotube composite

    NASA Astrophysics Data System (ADS)

    Emelianov, A. V.; Akhmadishina, K. F.; Romashkin, A. V.; Nevolin, V. K.; Bobrinetskiy, I. I.

    2015-01-01

    We propose a new concept in the formation of transparent conducting films based on single-walled carbon nanotubes (SWNTs) and polyaniline (PANI) on a flexible polyethylene naphthalate substrate. It is established that the resistance of SWNT-PANI composite films decreases to less than half as compared to pure nanotubes, while the transparency is retained. Mechanisms responsible for a change in the conductivity of composite molecular systems are discussed based on differences in the transport of charge carriers in nanotubes and the polymer with allowance for their interaction.

  11. Methylmethacrylate Casting Model of Temporal Bone

    PubMed Central

    Kubo, Shigeki; Fukushima, Takanori; Yoshimine, Toshiki; Miki, Hideyuki; Hayakawa, Toru

    1998-01-01

    Methylmethacrylate casting model of the temporal bone simulating the translabyrinthine approach from the bone surface down to the internal auditory canal was developed in order to help to understand the complex anatomy that is often encountered during skull base surgery. Using a cadaver temporal bone and applying dental impression technique, fine structures, such as semicircular canals and facial nerve, were precisely reproduced in a life-size resin casting model. This simple cost-effective modeling method would facilitate both anatomical research and medical education by improving our understanding of the complex anatomy of the temporal bone. ImagesFigure 2Figure 3Figure 4p21-b PMID:17171038

  12. Study of water vapour permeability of protein and gum-based edible films by a photothermal method

    NASA Astrophysics Data System (ADS)

    Tomás, S. A.; Saavedra, R.; Cruz, A.; Pedroza-Islas, R.; San Martín, E.

    2005-06-01

    The water vapour permeability of protein and gum-based edible films was studied by means of a photothermal method. The films were prepared with two basic ingredients, whey protein concentrate and mesquite gum, according to the proportions 75:25, 50:50, 25:75, and 0:100 (weight:weight). The water vapour diffusion coefficient of the analyzed films was found within the interval 0.37 × 10-6 to 2.04 × 10-6 cm^2/s, increasing linearly by increasing the mesquite gum composition in the films. The incorporation of mesquite gum in films produces less effective moisture barriers due to its highly hydrophilic property.

  13. CO Responses of Sensors Based on Cerium Oxide Thick Films Prepared from Clustered Spherical Nanoparticles

    PubMed Central

    Izu, Noriya; Matsubara, Ichiro; Itoh, Toshio; Akamatsu, Takafumi; Shin, Woosuck

    2013-01-01

    Various types of CO sensors based on cerium oxide (ceria) have been reported recently. It has also been reported that the response speed of CO sensors fabricated from porous ceria thick films comprising nanoparticles is extremely high. However, the response value of such sensors is not suitably high. In this study, we investigated methods of improving the response values of CO sensors based on ceria and prepared gas sensors from core-shell ceria polymer hybrid nanoparticles. These hybrid nanoparticles have been reported to have a unique structure: The core consists of a cluster of ceria crystallites several nanometers in size. We compared the characteristics of the sensors based on thick films prepared from core-shell nanoparticles with those of sensors based on thick films prepared from conventionally used precipitated nanoparticles. The sensors prepared from the core-shell nanoparticles exhibited a resistance that was ten times greater than that of the sensors prepared from the precipitated nanoparticles. The response values of the gas sensors based on the core-shell nanoparticles also was higher than that of the sensors based on the precipitated nanoparticles. Finally, improvements in sensor response were also noticed after the addition of Au nanoparticles to the thick films used to fabricate the two types of sensors. PMID:23529123

  14. Spray casting project final report

    SciTech Connect

    Churnetski, S.R.; Thompson, J.E.

    1996-08-01

    Lockheed Martin Energy Systems, Inc. (Energy Systems), along with other participating organizations, has been exploring the feasibility of spray casting depleted uranium (DU) to near-net shape as a waste minimization effort. Although this technology would be useful in a variety of applications where DU was the material of choice, this effort was aimed primarily at gamma-shielding components for use in storage and transportation canisters for high-level radioactive waste, particularly in the Multipurpose Canister (MPC) application. In addition to the waste-minimization benefits, spray casting would simplify the manufacturing process by allowing the shielding components for MPC to be produced as a single component, as opposed to multiple components with many fabrication and assembly steps. In earlier experiments, surrogate materials were used to simulate the properties (specifically reactivity and density) of DU. Based on the positive results from those studies, the project participants decided that further evaluation of the issues and concerns that would accompany spraying DU was warranted. That evaluation occupied substantially all of Fiscal Year 1995, yielding conceptual designs for both an intermediate facility and a production facility and their associated engineering estimates. An intermediate facility was included in this study to allow further technology development in spraying DU. Although spraying DU to near-net shape seems to be feasible, a number of technical, engineering, and safety issues would need to be evaluated before proceeding with a production facility. This report is intended to document the results from the spray-casting project and to provide information needed by anyone interested in proceeding to the next step.

  15. Erasable thin-film optical diode based on a photoresponsive liquid crystal polymer.

    PubMed

    Zhang, Xinping; Zhang, Jian; Sun, Yujian; Yang, Huai; Yu, Haifeng

    2014-04-01

    We report a thin-film optical diode written into thin films of a liquid-crystalline polymer (LCP), which is based on the photoinduced LC-to-isotropic phase transition of LCPs. The interference pattern between a collimated and a focused UV laser beam is imprinted as chirped volume-phase gratings in photoresponsive LCP films and no further processing steps like development or liftoff are required for the fabrication. The resultant thin-film device not only possesses the fundamental functions of an optical lens for laser beam focusing, but also shows diode effects with the focusing/defocusing function dependent on the direction of light incidence and orientation of the device. Furthermore, this photonic thin-film lens exhibits a spatially tunable spectroscopic response, revealing a unique physics of secondary excitations of resonance modes of the single-layer LCP waveguide grating structures. This reveals the mechanisms for the focusing/defocusing of laser beams by chirped grating structures. Erasability and reconstructibility of the photoresponsive LCPs guarantee rewritability of the thin-film diode lens. PMID:24584886

  16. Reversible potentiometric oxygen sensors based on polymeric and metallic film electrodes.

    PubMed

    Yim, H S; Meyerhoff, M E

    1992-09-01

    Various materials and sensor configurations that exhibit reversible potentiometric responses to the partial pressure of oxygen at room temperature in neutral pH solution are examined. In one arrangement, platinum electrodes are coated with plasticized poly(vinyl chloride) films doped with a cobalt(II) tetraethylene pentamine complex. For such sensors, potentiometric oxygen response is attributed to a mixed potential originating from the underlying platinum electrode surface as well as a change in redox potential of the Co(II)-tetren-doped film as the complex binds oxygen reversibly. The response due to the platinum surface is prolonged by the presence of the Co(II)-tetren/PVC film. Alternately, thin films of metallic copper, electrochemically deposited on platinum and/or sputtered or vapor deposited on a single crystal silicon substrate, may be used for reversible oxygen sensing. The long-term reversibility and potentiometric stability of such copper film-based sensors is enhanced (up to 1 month) by preventing the formation of cuprous oxide on the surfaces via the application of an external nonpolarizing cathodic current through the working electrode or by specifically using sputtered copper films that have [100] preferred crystal structures as determined by X-ray diffraction. The implications of these findings in relation to fabricating analytically useful potentiometric oxygen sensors are discussed. PMID:1416035

  17. Thin film polarizer and color filter based on photo-polymerizable nematic liquid crystal

    NASA Astrophysics Data System (ADS)

    Mohammadimasoudi, Mohammad; Neyts, Kristiaan; Beeckman, Jeroen

    2015-03-01

    We present a method to fabricate a thin film color filter based on a mixture of photo-polymerizable liquid crystal and chiral dopant. A chiral nematic liquid crystal layer reflects light for a certain wavelength interval ?? (= ?n.P) with the period and ?n the birefringence of the liquid crystal. The reflection band is determined by the chiral dopant concentration. The bandwidth is limited to 80nm and the reflectance is at most 50% for unpolarized incident light. The thin color filter is interesting for innovative applications like polarizer-free reflective displays, polarization-independent devices, stealth technologies, or smart switchable reflective windows to control solar light and heat. The reflected light has strong color saturation without absorption because of the sharp band edges. A thin film polarizer is developed by using a mixture of photo-polymerizable liquid crystal and color-neutral dye. The fabricated thin film absorbs light that is polarized parallel to the c axis of the LC. The obtained polarization ratio is 80% for a film of only 12 ?m. The thin film polarizer and the color filter feature excellent film characteristics without domains and can be detached from the substrate which is useful for e.g. flexible substrates.

  18. Hydrogen storage in Ti, V and their oxides-based thin films

    NASA Astrophysics Data System (ADS)

    Tarnawski, Z.; Zakrzewska, K.; Kim-Ngan, N.-T. H.; Krupska, M.; Sowa, S.; Drogowska, K.; Havela, L.; Balogh, A. G.

    2015-03-01

    We have investigated the hydrogen storage ability and the effect of hydrogenation on structure and physical properties of Ti/V and their oxides-based thin films. A series of Ti–TiO2 and VOx–TiO2 thin films with different layer structures, geometries and thicknesses have been prepared by the sputtering technique on different (Si(111), SiO2, C) substrates. For the Ti–TiO2–Ti films up to 50 at.% of hydrogen can be stored in the Ti layers, while the hydrogen can penetrate without accumulation through the TiO2 layer. A large hydrogen storage was also found in some V2O5–TiO2 films. Hydrogen could also remove the preferential orientation in the Ti films and induce a transition of V2O5 to VO2 in the films. Invited talk at the 7th International Workshop on Advanced Materials Science and Nanotechnology IWAMSN2014, 2-6 November, 2014, Ha Long, Vietnam.

  19. An Update on ToxCast?

    EPA Science Inventory

    In its first phase, ToxCast? is profiling over 300 well-characterized chemicals (primarily pesticides) in over 400 HTS endpoints. These endpoints include biochemical assays of protein function, cell-based transcriptional reporter assays, multi-cell interaction assays, transcripto...

  20. CAST: Collaborative Agents for Simulating Teamwork

    Microsoft Academic Search

    John Yen; Jianwen Yin; Thomas R. Ioerger; Michael S. Miller; Dianxiang Xu; Richard A. Volz

    2001-01-01

    Psychological studies on teamwork have shown that an effective team often can anticipate information needs of teammates based on a shared mental model. Existing multi-agent models for teamwork are limited in their ability to support proactive information exchange among teammates. To address this issue, we have developed and implemented a multi-agent architecture called CAST that simulates teamwork and supports proactive

  1. Hickey, TT162, Casts 2-5 Hickey, TT162, Casts 2-5, page 1

    E-print Network

    Hickey, Barbara

    Hickey, TT162, Casts 2-5 Hickey, TT162, Casts 2-5, page 1 CTD002 #12;Hickey, TT162, Casts 2-5 Hickey, TT162, Casts 2-5, page 2 CTD002 #12;Hickey, TT162, Casts 2-5 Hickey, TT162, Casts 2-5, page 3 CTD002 #12;Hickey, TT162, Casts 2-5 Hickey, TT162, Casts 2-5, page 4 CTD002 #12;Hickey, TT162, Casts 2

  2. Hickey, TT136, casts 3-5 Hickey, TT136, casts 3-5, page 1

    E-print Network

    Hickey, Barbara

    Hickey, TT136, casts 3-5 Hickey, TT136, casts 3-5, page 1 CTD003 #12;Hickey, TT136, casts 3-5 Hickey, TT136, casts 3-5, page 2 CTD003 #12;Hickey, TT136, casts 3-5 Hickey, TT136, casts 3-5, page 3 CTD003 #12;Hickey, TT136, casts 3-5 Hickey, TT136, casts 3-5, page 4 CTD003 #12;Hickey, TT136, casts 3

  3. Hickey, TT136, casts 6-10 Hickey, TT136, casts 6-10, page 1

    E-print Network

    Hickey, Barbara

    Hickey, TT136, casts 6-10 Hickey, TT136, casts 6-10, page 1 CTD006 #12;Hickey, TT136, casts 6-10 Hickey, TT136, casts 6-10, page 2 CTD006 #12;Hickey, TT136, casts 6-10 Hickey, TT136, casts 6-10, page 3 CTD006 #12;Hickey, TT136, casts 6-10 Hickey, TT136, casts 6-10, page 4 CTD006 #12;Hickey, TT136, casts

  4. Hickey, TT162, casts 6-7 Hickey, TT162, casts 6-7, page 1

    E-print Network

    Hickey, Barbara

    CTD006 Hickey, TT162, casts 6-7 Hickey, TT162, casts 6-7, page 1 #12;CTD006 Hickey, TT162, casts 6-7 Hickey, TT162, casts 6-7, page 2 #12;CTD006 Hickey, TT162, casts 6-7 Hickey, TT162, casts 6-7, page 3 #12;CTD006 Hickey, TT162, casts 6-7 Hickey, TT162, casts 6-7, page 4 #12;CTD006 Hickey, TT162, casts 6

  5. Base-metal dental casting alloy biocompatibility assessment using a human-derived three-dimensional oral mucosal model.

    PubMed

    McGinley, E L; Moran, G P; Fleming, G J P

    2012-01-01

    Nickel-chromium (Ni-Cr) alloys used in fixed prosthodontics have been associated with type IV Ni-induced hypersensitivity. We hypothesised that the full-thickness human-derived oral mucosa model employed for biocompatibility testing of base-metal dental alloys would provide insights into the mechanisms of Ni-induced toxicity. Primary oral keratinocytes and gingival fibroblasts were seeded onto Alloderm™ and maintained until full thickness was achieved prior to Ni-Cr and cobalt-chromium (Co-Cr) alloy disc exposure (2-72 h). Biocompatibility assessment involved histological analyses with cell viability measurements, oxidative stress responses, inflammatory cytokine expression and cellular toxicity analyses. Inductively coupled plasma mass spectrometry analysis determined elemental ion release levels. We detected adverse morphology with significant reductions in cell viability, significant increases in oxidative stress, inflammatory cytokine expression and cellular toxicity for the Ni-Cr alloy-treated oral mucosal models compared with untreated oral mucosal models, and adverse effects were increased for the Ni-Cr alloy that leached the most Ni. Co-Cr demonstrated significantly enhanced biocompatibility compared with Ni-Cr alloy-treated oral mucosal models. The human-derived full-thickness oral mucosal model discriminated between dental alloys and provided insights into the mechanisms of Ni-induced toxicity, highlighting potential clinical relevance. PMID:21889621

  6. SICS. A Sensor-Based In-Line Control System for the Surfaces of Continuously Cast Slabs

    SciTech Connect

    Chang, Tzyy-Shuh [OG Technologies, Inc., Ann Arbor, MI (United States)

    2013-09-23

    The Phase II project has been carried out in accordance to the proposed tasks and budget, based on the original and extended schedule. The R&D team designed and implemented the test unit for the full width coverage, installed the unit in a caster. The development work further included enhanced image processing, in-depth defect study and process control models. The function, operation, and maintenance of the SICS was thoroughly studied during the Phase II research. The experience indicates additional hardware and procedures are required to make the SICS a commercially ready product in operation and maintenance aspect. Such developments have been finished and the team is contacting potential customers for the first commercial installation of SICS. Additionally, OGT is exploring the possibility to team up with a US company that specializes in surface cleaning for slabs/blooms/billets such that the in-line surface inspection can be integrated with in-line surface clean up for the maximum benefit to the steel industry.

  7. AMCC casting development, volume 2

    NASA Technical Reports Server (NTRS)

    1995-01-01

    PCC successfully cast and performed nondestructive testing, FPI and x-ray, on seventeen AMCC castings. Destructive testing, lab analysis and chemical milling, was performed on eleven of the castings and the remaining six castings were shipped to NASA or Aerojet. Two of the six castings shipped, lots 015 and 016, were fully processed per blueprint requirements. PCC has fully developed the gating and processing parameters of this part and feels the part could be implemented into production, after four more castings have been completed to ensure the repeatability of the process. The AMCC casting has been a technically challenging part due to its size, configuration, and alloy type. The height and weight of the wax pattern assembly necessitated the development of a hollow gating system to ensure structural integrity of the shell throughout the investment process. The complexity in the jacket area of the casting required the development of an innovative casting technology that PCC has termed 'TGC' or thermal gradient control. This method of setting up thermal gradients in the casting during solidification represents a significant process improvement for PCC and has been successfully implemented on other programs. The alloy, JBK75, is a relatively new alloy in the investment casting arena and required our engineering staff to learn the gating, processing, and dimensional characteristics of the material.

  8. The effect of nanocomposite packaging carbon nanotube base on organoleptic and fungal growth of Mazafati brand dates

    NASA Astrophysics Data System (ADS)

    Asgari, Parinaz; Moradi, Omid; Tajeddin, Behjat

    2014-03-01

    In this work, nanocomposite low-density polyethylene films with carbon nanotube base were prepared by solution casting from boiling xylene. Fresh Mazafati dates were placed on the packages obtained from films and stored at ambient temperature. In addition, the fungal growth and sensory attributes were monitored on the 0th, 30th, 60th, and 90th days of storage. Although films containing carbon nanotube increased shelf life of Mazafati dates compared to controls, some of the characteristics of sensory were lost.

  9. Electrochemical DNA biosensors based on thin gold films sputtered on capacitive nanoporous niobium oxide

    Microsoft Academic Search

    Sangchul Rho; Deokjin Jahng; Jae Hoon Lim; Jinsub Choi; Jeong Ho Chang; Sang Cheon Lee; Kyung Ja Kim

    2008-01-01

    Electrochemical DNA biosensors based on a thin gold film sputtered on anodic porous niobium oxide (Au@Nb2O5) are studied in detail here. We found that the novel DNA biosensor based on Au@Nb2O5 is superior to those based on the bulk gold electrode or niobium oxide electrode. For example, the novel method does not require any time-consuming cleaning step in order to

  10. Characterization of peanut-soybean films for food packaging applications 

    E-print Network

    Tellez Garay, Angela Maria

    1999-01-01

    Edible films made from peanut and soybean were developed using casting and single-screw extrusion methods. The effect of time, formulation and processing method on the rheological, barrier and physical properties of the experimental films were...

  11. On-wafer millimeter wave notch filter based on barium hexagonal ferrite thin films on platinum

    NASA Astrophysics Data System (ADS)

    Harward, Ian Roylance

    In this work, the growth of BaM and Al doped Ba M thin films on Pt templates, layered on a Si wafer, is demonstrated using a newly developed metallo-organic decomposition (MOD) process. It is shown that the BaM films are polycrystalline, with preferred perpendicular c-axis grain orientation. The magnetic properties such as anisotropy field, saturation magnetization, and remnant magnetization are studied as a function of temperature and film composition, and are shown to be correlated to the film microstructure. It is shown that these films exhibit high remnant magnetization, a property not measured in BaM single crystals, meaning a biasing magnet may not be necessary for millimeter wave device applications. Ferromagnetic resonance (FMR) studies were performed on the ferrite films using the tool developed at UCCS for the study of high frequency magnetic materials, the broadband FMR (BFMR) system. The instrument is described in great detail, and the FMR studies on BaM show that the MOD-grown films exhibit narrow FMR linewidths, on the order of 150 Oe, and are therefore of sufficient quality for use in mm wave devices. Finally, notch filters using the Pt/BaM are demonstrated. The filters are based on a microstrip design, where the Pt serves as the ground plane and the BaM is part of the dielectric. The Ba M absorbs signals at the ferromagnetic resonance frequency, which takes place in the mm wave range. The filters described were based on pure BaM, but Al doped BaM could easily be used to increase the operating frequency of the device. The operating frequency of these devices is also tunable using an externally applied magnetic field.

  12. Schottky Solar Cells Based on Colloidal Nancrystal Films

    SciTech Connect

    Luther, J. M.; Law, M.; Beard, M. C.; Song, Q.; Reese, M. O.; Ellingson, R. J.; Nozik, A. J.

    2008-01-01

    We describe here a simple, all-inorganic metal/NC/metal sandwich photovoltaic (PV) cell that produces an exceptionally large short-circuit photocurrent (>21 mA cm{sup -2}) by way of a Schottky junction at the negative electrode. The PV cell consists of a PbSe NC film, deposited via layer-by-layer (LbL) dip coating that yields an EQE of 55-65% in the visible and up to 25% in the infrared region of the solar spectrum, with a spectrally corrected AM1.5G power conversion efficiency of 2.1%. This NC device produces one of the largest short-circuit currents of any nanostructured solar cell, without the need for sintering, superlattice order or separate phases for electron and hole transport.

  13. Electrodeposition of Zn based nanostructure thin films for photovoltaic applications

    NASA Astrophysics Data System (ADS)

    Al-Bat'hi, S. A. M.

    2015-03-01

    We present here a systematic study on the synthesis thin films of various ZnO, CdO, ZnxCd1-x (O) and ZnTe nanostructures by electrodeposition technique with ZnCl2, CdCl2 and ZnSO4 solution as starting reactant. Several reaction parameters were examined to develop an optimal procedure for controlling the size, shape, and surface morphology of the nanostructure. The results showed that the morphology of the products can be carefully controlled through adjusting the concentration of the electrolyte. The products present well shaped Nanorods arrays at specific concentration and temperature. UV-VIS spectroscopy and X-ray diffraction results show that the product presents good crystallinity. A possible formation process has been proposed.

  14. A study of optical and electronic properties of organic thin film transistors based on naphthalenetetracarboxylic diimide derivatives

    NASA Astrophysics Data System (ADS)

    Yang, Dongxing

    The optical properties of spin cast thin films of N,N'-bis(3-phenoxy-3-phenoxy-phenoxy)-1,4,5,8-naphthalene-tetracarboxylic diimide (NDA-n2) and N,N'-bis(3-phenoxy-phenoxy)-1,4,5,8-naphthalene-tetracarboxylic diimide (NDA-n1) were investigated using spectroscopic ellipsometry (SE) complimented by optical absorption spectroscopy in the visible-near UV optical range and atomic force microscopy (AFM) for surface roughness. A combination of Tauc-Lorentzian and Gaussian oscillators model was used to fit the measurements obtained from SE. Film roughness results were also evaluated in the optical model using Bruggman Effective Medium Approximation (BEMA). The effect of different spin deposit conditions including spin speed, concentration of solution and deposition ambient on the NDA's film thickness, surface roughness, optical properties and optical anisotropy have been investigated. No anisotropy has been found for the spin cast film and moderate temperature annealing in high vacuum leads to film densification. Organic thin film transistors (OTFT's) were fabricated with NDA's as the active semiconductor layer, silicon dioxide (SiO2) as the gate dielectric, heavily doped silicon as the substrate, and vacuum evaporated gold lines as the source and drain contacts. The electronic properties were characterized using a custom built probe station. The custom probe station was automated with software program written in LabVIEW(TM). NDA's yielded a P-channel device. From transfer characteristic and turn-on plot, the charge mobility was calculated which was in the range of about 10 -2 cm2 V-1 s-1. Various post fabrication processes were carried out to optimize the device performance. Bottom contact configuration has shown higher charge mobility than top contact in this study. Moderate temperature annealing in high vacuum has improved the device mobility by several orders, yielding evidence for a hopping mechanism for charge transport in NDA's. The high mobility of NDA-n1 compared with NDA-n2 demonstrated that aryl-ether tail group hindered the charge transport in the film. Two alternate gate dielectric layers for the OTFT were also considered; while a non-polar low-K dielectric, polyethylene improved mobility; polar high-K dielectric, copolymer of vinylidene fluoride with trifluoroethylene had an adverse effect on mobility.

  15. Silver based SERS substrates fabricated from block copolymer thin film

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Lee, Wonjoo; Lee, Seung Yong; Gao, Zhenghan; Rabin, Oded; Briber, R. M.

    2013-03-01

    Poly (styrene-block-4-vinyl pyridine) (PS-b-P4VP, Mw = 47-b-10 kDa, PDI =1.10) thin films were used to form large-scale long range ordered self-assembled hexagonal patterns of vertically P4VP oriented cylinders in a PS matrix on Si substrates. The P4VP cylindrical domains were crosslinked and quaternized using 1,4-dibromobutane. Negatively charged 15nm gold nanoparticles were attached to the quaternized P4VP domains through Coulombic interactions. Silver was then grown on the gold seeds to create nanometer scale gaps between the nanoparticles. The gap between the nanoparticles was fine tuned by controlling the silver growth time. The substrates showed large enhancement factors in the Raman scattering signal for a broad range of incident wavelengths. Poly (styrene-block-4-vinyl pyridine) (PS-b-P4VP, Mw = 47-b-10 kDa, PDI =1.10) thin films were used to form large-scale long range ordered self-assembled hexagonal patterns of vertically P4VP oriented cylinders in a PS matrix on Si substrates. The P4VP cylindrical domains were crosslinked and quaternized using 1,4-dibromobutane. Negatively charged 15nm gold nanoparticles were attached to the quaternized P4VP domains through Coulombic interactions. Silver was then grown on the gold seeds to create nanometer scale gaps between the nanoparticles. The gap between the nanoparticles was fine tuned by controlling the silver growth time. The substrates showed large enhancement factors in the Raman scattering signal for a broad range of incident wavelengths. Present address: LG Chem Ltd, Information Technology & Electronic Materials R&D, Yuseong-gu Daejeon, South Korea

  16. Inference of optimal speed for sound centrifugal casting of Al-12Si alloys

    NASA Astrophysics Data System (ADS)

    Agari, Shailesh Rao; Mukunda, P. G.; Rao, Shrikantha S.; Sudhakar, K. G.

    2011-05-01

    True centrifugal casting is a standard casting technique for the manufacture of hollow, intricate and sound castings without the use of cores. The molten metal or alloy poured into the rotating mold forms a hollow casting as the centrifugal forces lift the liquid along the mold inner surface. When a mold is rotated at low and very high speeds defects are found in the final castings. Obtaining the critical speed for sound castings should not be a matter of guess or based on experience. The defects in the casting are mainly due to the behavior of the molten metal during the teeming and solidification process. Motion of molten metal at various speeds and its effect during casting are addressed in this paper. Eutectic Al-12Si alloy is taken as an experiment fluid and its performance during various rotational speeds is discussed.

  17. Photothermoelectric p-n Junction Photodetectors Based on Macroscopic Films of Aligned Carbon Nanotubes in the Terahertz Range

    E-print Network

    UG-20 Photothermoelectric p-n Junction Photodetectors Based on Macroscopic Films photothermoelectric p- n junction photodetectors based on macroscopic films of aligned CNTs [1]. CNTs were grown via-n junction. Two electrodes contacted each side, allowing the voltage across to be measured. A broadband

  18. Effect of chromium and phosphorus on the physical properties of iron and titanium-based amorphous metallic alloy films

    NASA Technical Reports Server (NTRS)

    Distefano, S.; Rameshan, R.; Fitzgerald, D. J.

    1991-01-01

    Amorphous iron and titanium-based alloys containing various amounts of chromium, phosphorus, and boron exhibit high corrosion resistance. Some physical properties of Fe and Ti-based metallic alloy films deposited on a glass substrate by a dc-magnetron sputtering technique are reported. The films were characterized using differential scanning calorimetry, stress analysis, SEM, XRD, SIMS, electron microprobe, and potentiodynamic polarization techniques.

  19. Modification of curvature-based thin-film residual stress measurement for MEMS applications

    NASA Astrophysics Data System (ADS)

    Chen, K.-S.; Ou, K.-S.

    2002-11-01

    Wafer level thin-film residual stress characterization is crucial for the structural reliability of many semiconductor and microelectromechanical systems (MEMS) devices. Because of its simplistic nature, the curvature measurement scheme is traditionally the most widely acknowledged method. Film stress is determined by converting the measured curvatures using Stoney's formula. However, this equation is based on linear beam theory and exhibits considerable errors if the rigidity of films cannot be neglected. This presents a problem for many MEMS related applications, where thicker films are usually required. In this paper, an assumed shaped energy-based approach is proposed to improve the curvature/stress conversion by simultaneously considering the effects of geometrical nonlinearity and mid-plane offsets. Solutions obtained by this method agree very well with those produced by nonlinear finite element simulations. Parametric studies show that for stiffer films, such as thick silicon carbide on silicon, this improved conversion model can provide a much more accurate curvature to stress conversion while the traditional conversion results in significant errors.

  20. Highlights on photocathodes based on thin films prepared by pulsed laser deposition

    NASA Astrophysics Data System (ADS)

    Lorusso, A.; Gontad, F.; Perrone, A.; Stankova, N.

    2011-09-01

    We review the current status of metallic photocathodes based on thin films prepared by pulsed laser deposition (PLD) and we explore ways to improve the performance of these devices. PLD seems to be a very efficient and suitable technique for producing adherent and uniform thin films. Time-resolved mass spectrometric investigations definitively suggest that the deposition of high-purity metallic thin films should be carried out in ultrahigh vacuum systems and after a deep and careful laser cleaning of the target surface. Moreover, the laser cleaning of the target surface is highly recommended not only to remove the first contaminated layers but also to improve the quality of the vacuum by reducing the partial pressure of reactive chemical species as H2O, H2, and O2 molecules. The challenge to realize high-purity Mg and Y thin films is very interesting for the photocathode R&D due to the good photoemission properties of these metals. Photocathodes based on Mg and Y thin films have been characterized by scanning electron microscopy and x-ray diffraction techniques to derive the morphological and structural features, respectively. They were also tested in a photodiode cell to deduce the photoelectron properties. The quantum efficiency of such photocathodes was systematically improved by in situ laser cleaning treatments of the surface in order to remove the contaminated layers reaching, in this way, the quantum efficiency of the corresponding bulk materials.

  1. Comparison of diverse nanomaterial bioactivity profiles based on high-throughput screening (HTS) in ToxCast? (FutureToxII)

    EPA Science Inventory

    Most nanomaterials (NMs) in commerce lack hazard data. Efficient NM testing requires suitable toxicity tests for prioritization of NMs to be tested. The EPA?s ToxCast program is screening NM bioactivities and ranking NMs by their bioactivities to inform targeted testing planning....

  2. Microstructural and electrical properties of CoCl2 doped HPMC/PVP polymer blend films

    NASA Astrophysics Data System (ADS)

    Somashekarappa, H.; Prakash, Y.; Mahadevaiah, Hemalatha, K.; Somashekar, R.

    2013-02-01

    Solid polymer electrolyte (SPE) based on Hydroxypropylemethylcellulose (HPMC) and Polyvinylpyrrolidone (PVP) polymer blend films complexed with different weight ratio of CoCl2 were prepared using solution casting method and investigated using X-ray line profile analysis. An attempt has been made to study the changes in crystal imperfection parameters in HPMC/PVP blend films with the increase in concentration of CoCl2. Results show that decrease in micro crystalline parameter values is accompanied with increase in the amorphous content in the film which is the reason for film to have more flexibility, biodegradability and good ionic conductivity. AC conductivity measurements in these films show that the conductivity increases as the concentration of CoCl2 increases. These films were suitable for electro chemical applications.

  3. Titanium. A review of investments for high temperature casting.

    PubMed

    Mori, T

    1993-01-01

    Conventional silica (SiO2) based dental casting investments are used for the casting of pure titanium using casting machines specifically developed for this metal. Highly reactive molten titanium reduces SiO2 and titanium is in turn oxidised. For this reason possible alternatives to SiO2 have been studied in the past decade and MgO and Al2O3 are the most common in current commercial investments released for titanium casting. The surface of titanium castings presents a layered structure and its evaluation in relation to clinical performance requires further study. It is also urgently required to know setting and thermal behaviour of the newly developed investments for successful compensation of metal shrinkage. PMID:8695190

  4. Solid-State Densification of Spun-Cast Self-Assembled Monolayers for Use in Ultra-Thin Hybrid Dielectrics.

    PubMed

    Hutchins, Daniel O; Acton, Orb; Weidner, Tobias; Cernetic, Nathan; Baio, Joe E; Castner, David G; Ma, Hong; Jen, Alex K-Y

    2012-11-15

    Ultra-thin self-assembled monolayer (SAM)-oxide hybrid dielectrics have gained significant interest for their application in low-voltage organic thin film transistors (OTFTs). A [8-(11-phenoxy-undecyloxy)-octyl]phosphonic acid (PhO-19-PA) SAM on ultrathin AlOx (2.5 nm) has been developed to significantly enhance the dielectric performance of inorganic oxides through reduction of leakage current while maintaining similar capacitance to the underlying oxide structure. Rapid processing of this SAM in ambient conditions is achieved by spin coating, however, as-cast monolayer density is not sufficient for dielectric applications. Thermal annealing of a bulk spun-cast PhO-19-PA molecular film is explored as a mechanism for SAM densification. SAM density, or surface coverage, and order are examined as a function of annealing temperature. These SAM characteristics are probed through atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and near edge X-ray absorption fine structure spectroscopy (NEXAFS). It is found that at temperatures sufficient to melt the as-cast bulk molecular film, SAM densification is achieved; leading to a rapid processing technique for high performance SAM-oxide hybrid dielectric systems utilizing a single wet processing step. To demonstrate low-voltage devices based on this hybrid dielectric (with leakage current density of 7.7×10(-8) A cm(-2) and capacitance density of 0.62 µF cm(-2) at 3 V), pentacene thin-film transistors (OTFTs) are fabricated and yield sub 2 V operation and charge carrier mobilites of up to 1.1 cm(2) V(-1) s(-1). PMID:24288423

  5. Solid-State Densification of Spun-Cast Self-Assembled Monolayers for Use in Ultra-Thin Hybrid Dielectrics

    PubMed Central

    Hutchins, Daniel O.; Acton, Orb; Weidner, Tobias; Cernetic, Nathan; Baio, Joe E.; Castner, David G.; Ma, Hong; Jen, Alex K.-Y.

    2013-01-01

    Ultra-thin self-assembled monolayer (SAM)-oxide hybrid dielectrics have gained significant interest for their application in low-voltage organic thin film transistors (OTFTs). A [8-(11-phenoxy-undecyloxy)-octyl]phosphonic acid (PhO-19-PA) SAM on ultrathin AlOx (2.5 nm) has been developed to significantly enhance the dielectric performance of inorganic oxides through reduction of leakage current while maintaining similar capacitance to the underlying oxide structure. Rapid processing of this SAM in ambient conditions is achieved by spin coating, however, as-cast monolayer density is not sufficient for dielectric applications. Thermal annealing of a bulk spun-cast PhO-19-PA molecular film is explored as a mechanism for SAM densification. SAM density, or surface coverage, and order are examined as a function of annealing temperature. These SAM characteristics are probed through atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and near edge X-ray absorption fine structure spectroscopy (NEXAFS). It is found that at temperatures sufficient to melt the as-cast bulk molecular film, SAM densification is achieved; leading to a rapid processing technique for high performance SAM-oxide hybrid dielectric systems utilizing a single wet processing step. To demonstrate low-voltage devices based on this hybrid dielectric (with leakage current density of 7.7×10?8 A cm?2 and capacitance density of 0.62 µF cm?2 at 3 V), pentacene thin-film transistors (OTFTs) are fabricated and yield sub 2 V operation and charge carrier mobilites of up to 1.1 cm2 V?1 s?1. PMID:24288423

  6. [Casting faults and structural studies on bonded alloys comparing centrifugal castings and vacuum pressure castings].

    PubMed

    Fuchs, P; Küfmann, W

    1978-07-01

    The casting processes in use today such as centrifugal casting and vacuum pressure casting were compared with one another. An effort was made to answer the question whether the occurrence of shrink cavities and the mean diameter of the grain of the alloy is dependent on the method of casting. 80 crowns were made by both processes from the baked alloys Degudent Universal, Degudent N and the trial alloy 4437 of the firm Degusa. Slice sections were examined for macro and micro-porosity and the structural appearance was evaluated by linear analysis. Statistical analysis showed that casting faults and casting structure is independent of the method used and their causes must be found in the conditions of casting and the composition of the alloy. PMID:352670

  7. Development and environmental application of a nitrate selective microsensor based on doped polypyrrole films

    Microsoft Academic Search

    Tatyana A. Bendikov; Juyoul Kim; Thomas C. Harmon

    2005-01-01

    This work describes the development and testing of a sensitive and selective potentiometric nitrate microsensor based on doped polypyrrole films. Utilizing 6–7?m carbon fibers as a substrate for pyrrole electropolymerization allowed fabrication of flexible, miniature and inexpensive sensors for in situ monitoring of nitrate. The sensors have a rapid response (several seconds) and in their characteristics are competitive with expensive

  8. Effects of nanoclay type on the physical and antimicrobial properties of PVOH-based nanocomposite films

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyvinyl alcohols-based nanocomposite films were fabricated with four types of montmorillonite (MMT) nanoclay, including 18-amino stearic acid (I.24TL), methyl, bis hydroxyethyl, octadecyl ammonium (I.34TCN), di-methyl, di-hydrogenated tallow ammonium/siloxane (I.44PSS) organically modified MMT, an...

  9. Composite edible films based on hydroxypropyl methyl cellulose reinforced with microcrystalline cellulose nanoparticles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It has been stated that hydroxypropyl methyl cellulose (HPMC) based films have promising applications in the food industry because of their environmental appeal, low cost, flexibility and transparency. Nevertheless, their mechanical and moisture barrier properties should be improved. The aim of th...

  10. Flexible and transparent supercapacitor based on In2O3 nanowire/carbon nanotube heterogeneous films

    E-print Network

    Zhou, Chongwu

    Flexible and transparent supercapacitor based on In2O3 nanowire/carbon nanotube heterogeneous films; accepted 17 December 2008; published online 28 January 2009 In this paper, a supercapacitor galvanostatic measurements. In addition, to study the stability of flexible and transparent supercapacitor

  11. FLUORESCENCE AND FIBER-OPTICS BASED REAL-TIME THICKNESS SENSOR FOR DYNAMIC LIQUID FILMS

    E-print Network

    Narain, Amitabh

    1 FLUORESCENCE AND FIBER-OPTICS BASED REAL-TIME THICKNESS SENSOR FOR DYNAMIC LIQUID FILMS T. W. Ng phenomena and fiber-optic technology has been developed and reported here. Measurements from this sensor research and development fields. This paper focuses on a sensor capable of measuring interfacial wave

  12. Tradition and Change in Modern Morocco, An Instructional Unit Based on Film Study.

    ERIC Educational Resources Information Center

    Murphy, E. Jefferson

    The learning unit for grade levels 8, 9, or 10 is based upon viewing and discussing the film "Morocco: Chaoui Faces His Future." Among the learning objectives of the unit are the following: (1) to expand inquiry skills and the ability to formulate concepts, generalizations, and hypotheses; (2) to introduce the student to the interplay of forces of…

  13. Quantitative determination of element distributions in silicon based thin film solar cells using SNMS

    Microsoft Academic Search

    M. Gastel; U. Breuer; H. Holzbrecher; J. S. Becker; H.-J. Dietze; M. Kubon; H. Wagner

    1995-01-01

    The determination of elemental distributions in thin film solar cells based on amorphous silicon using electron beam SNMS is possible by quantifying the measured ion intensities. The relative sensitivity factors (RSFs) for all elements measured have to be known. The RSFs have been determined experimentally using implantation and bulk standards with known concentrations of the interesting elements. The measured RSFs

  14. Thin FeC Alloy Solid Film Based Fiber Optic Corrosion Sensor

    Microsoft Academic Search

    Guofu Qiao; Zhi Zhou; Jinping Ou

    2006-01-01

    In last few years, some transmitted type fiber optic corrosion sensors (FOCS) have emerged, but the fragile character makes them difficultly use in practice. In this paper, a novel thin Fe-C alloy solid film based fiber optic corrosion sensor has been developed. The sensing section is located at one end of the fiber. A double layer classic slab model has

  15. Characterization of thin metallic films in MEMS-based electrical contacts

    Microsoft Academic Search

    Ben Dvorak

    Microelectromechanical systems (MEMS) and MEMS based electrical contacts are an important area of research and science which has directly benefited from the use of thin films. Microelectromechanical systems have existed and been studied for a num- ber of years and specifically micromechanical switches and relays were among the first devices to be studied (1). The development of MEMS devices and

  16. Optoacoustic sources: a practical Green function-based model for thin film laser-ultrasound generation

    Microsoft Academic Search

    D. Menichelli; E. Biagi

    2001-01-01

    The theory of optoacoustic generation of ultrasound in fluids through the thermoelastic effect has been addressed, considering the case of a thin absorbing film used as a target for the laser light. A novel theoretical method, based on the use of the Green function and of the image theorem, has been developed and discussed. The model is mainly carried out

  17. Effects of hygrothermal aging on epoxy-based anisotropic conductive film

    Microsoft Academic Search

    Y. C. Lin; Xu Chen; H. J. Zhang; Z. P. Wang

    2006-01-01

    The epoxy-based anisotropic conductive film (ACF) joints have the potential of being exposed to a hygrothermal environment and susceptible to moisture sorption. The long-term hygrothermal aging will induce the irreversible damages of epoxy resins system due to susceptibility of the polymer to hydrolysis, oxidation, etc. In this study, the hygrothermal environment test was used as an accelerator for the degradation

  18. PREDICTING THE BARRIER EFFECTIVENESS OF FLUOROPOLYMER FILM-BASED PROTECTIVE CLOTHING MATERIALS

    EPA Science Inventory

    Emergency spill response and hazardous waste cleanup activities often require protective clothing that is an effective barrier to a wide range of chemicals and chemical mixtures. everal clothing products are now available that are based on high barrier films and laminates. xample...

  19. Transparent, conducting films based on metal\\/dielectric photonic band gaps

    Microsoft Academic Search

    Mark J. Bloemer; Michael Scalora; G. D'Aguanno; Charles M. Bowden; Salvatore Baglio; Concita Sibilia; M. Centini; Mario Bertolotti

    1999-01-01

    A transparent conductor has been developed based on 1D metal\\/dielectric photonic band gap structures. Laminated metal\\/dielectric filters containing 100 nm of silver have been fabricated with > 50% transmittance. Applications for transparent, conducting films include antennas embedded in windshields, electrodes on flat panel displays, electromagnetic shielding, and solar window panes.

  20. Enhanced frequency response of a highly transparent PVDF-graphene based thin film acoustic actuator.

    PubMed

    Lee, James S; Shin, Keun-Young; Kim, Chanhoi; Jang, Jyongsik

    2013-12-01

    A high-performance polyvinylidene fluoride (PVDF) based thin film acoustic actuator with chemical vapor deposition (CVD) graphene electrodes was successfully fabricated. Importantly, it showed 60, 19, and 22% enhancement in the bass, middle and treble frequency response, respectively. PMID:24136447

  1. Memory Switches Based On MnO2-x Thin Films

    NASA Technical Reports Server (NTRS)

    Ramesham, Rajeshuni; Thakoor, Anilkumar P.; Lambe, John

    1989-01-01

    Thin films of Mn02-x at intersections between metallic row and column conductors serve as switching elements for nonvolatile electronic memories. "On"-state resistance adjustable, and on-to-off transition irreversible. Elements electrically programmable and especially suitable for use in associative electronic memories based on neural-network concepts.

  2. Enhanced antimicrobial activity of starch-based film impregnated with thermally processed tannic acid, a strong antioxidant.

    PubMed

    Pyla, Rajkumar; Kim, Tae-Jo; Silva, Juan L; Jung, Yean-Sung

    2010-02-28

    Starch-based films impregnated with fresh tannic acid (FTA/starch film) and thermally processed tannic acid (PTA/starch film) were assessed for inhibition of Escherichia coli O157:H7 and Listeria monocytogenes. Disc-diffusion assay revealed that the PTA/starch film showed larger clear zone around the film on the bacterial lawn than the FTA/starch film at the same tannic acid concentrations (0.45 to 4.5mg per disc). Viable cell count assays in tryptic soy broth showed that the PTA/starch film also had a stronger antimicrobial activity on these foodborne pathogens than the FTA/starch film. L. monocytogenes did not replicate in trypic soy broth containing the FTA/starch film for the first 8h but multiplied up to 9.22 log CFU/ml at 48 h of incubation. The PTA/starch film caused a 2.72-log decrease in L. monocytogenes cells over the same time period. While 5-log E. coli O157:H7 cells were inactivated by the FTA/starch film within 48 h, more than 7-log E. coli O157:H7 cells were killed by the PTA/starch film over the same period. The antimicrobial activity of FTA/starch and PTA/starch film was primarily pH independent. HPLC measurement of the FTA or PTA release from starch film in water revealed that their release kinetic curves were in well match with their inactivation curves for E. coli O157:H7 and L. monocytogenes in 0.1% peptone water. In addition to antimicrobial activity, FTA showed antioxidant activity on soybean oil by doubling the induction time of oil oxidation. PTA further enhanced the oxidative stability of the oil by 17%. These results suggested that the use of processed tannic acid in starch films could improve the safety and quality of foods. PMID:20051308

  3. Development of Materials Integration Strategies for Electroceramic Film-Based Devices Via Complementary In Situ and Ex Situ Studies of Film Growth and Interface Processes

    Microsoft Academic Search

    O. Auciello; A. M. Dhote; R. Ramesh; B. T. Liu; S. Aggarwal; A. H. Mueller; N. A. Suvarova; E. A. Irene

    2002-01-01

    We review our studies of film growth and interface processes performed using complementary in situ and ex situ characterization techniques that provide valuable information critical to the development of materials integration strategies for the fabrication of electroceramic film-based devices. Specifically, we review our work performed using in situ time-of-flight ion scattering and recoil spectroscopy (TOF-ISARS) \\/ X-ray photoemission spectroscopy (XPS)

  4. Casting larger polycrystalline silicon ingots

    SciTech Connect

    Wohlgemuth, J.; Tomlinson, T.; Cliber, J.; Shea, S.; Narayanan, M.

    1995-08-01

    Solarex has developed and patented a directional solidification casting process specifically designed for photovoltaics. In this process, silicon feedstock is melted in a ceramic crucible and solidified into a large grained semicrystalline silicon ingot. In-house manufacture of low cost, high purity ceramics is a key to the low cost fabrication of Solarex polycrystalline wafers. The casting process is performed in Solarex designed casting stations. The casting operation is computer controlled. There are no moving parts (except for the loading and unloading) so the growth process proceeds with virtually no operator intervention Today Solarex casting stations are used to produce ingots from which 4 bricks, each 11.4 cm by 11.4 cm in cross section, are cut. The stations themselves are physically capable of holding larger ingots, that would yield either: 4 bricks, 15 cm by 15 an; or 9 bricks, 11.4 cm by 11.4 an in cross-section. One of the tasks in the Solarex Cast Polycrystalline Silicon PVMaT Program is to design and modify one of the castings stations to cast these larger ingots. If successful, this effort will increase the production capacity of Solarex`s casting stations by 73% and reduce the labor content for casting by an equivalent percentage.

  5. Pulsed laser deposition of Co and Fe-based amorphous magnetic films and multilayers

    Microsoft Academic Search

    S. Acquaviva; A. P. Caricato; E. D'Anna; M. Fernández; A. Luches; Z. Frait; E. Majkova; M. Ozvold; S. Luby; P. Mengucci

    2003-01-01

    Magnetic films and multilayers were prepared by pulsed laser ablation of Co- and Fe-based amorphous magnetic ribbons with compositions Co67Cr7Fe4Si8B14 and Fe73.5Nb3Cu1Si13.5B9, respectively. Targets were ablated in vacuum (?10?5 Pa) by KrF excimer laser pulses at fluences from 3 to 7 J\\/cm2. Films were deposited on oxidized silicon wafers, placed 80 mm apart from the target. From X-ray diffraction spectra

  6. Nano particle porous alumina based thin film parallel plate capacitive humidity sensor

    NASA Astrophysics Data System (ADS)

    Kumar, Shailesh

    2014-04-01

    A Relative humidity sensor was fabricated based on porous thin film of ?-Al2O3 formed between the parallel Pd/Ag electrodes working on capacitive technique. The film was fabricated by dip coating of sol solution obtained from the sol-gel method. The electrical parameters of the sensor have been determined by Agilent 4294A impedance analyzer. The sensor so obtained is found to be sensitive in 10 to 90% RH. The response time of the sensor is very low around 24 seconds and recovery time 40 seconds.

  7. Electrochromic windows based on viologen-modified nanostructured TiO 2 films

    Microsoft Academic Search

    Rachel Cinnsealach; Gerrit Boschloo; S. Nagaraja Rao; Donald Fitzmaurice

    1998-01-01

    The construction of an electrochromic window based on a modified transparent nanostructured metal oxide film (TiO2 anatase, 4.0?m thick) supported on conducting glass (F-doped tin oxide, 10?\\/square, 0.5?m thick) is described. The nanostructured TiO2 film is modified by adsorption of a monolayer of the redox chromophore bis-(2-phosphonoethyl)-4,4?-bipyridinium dichloride, the electrolyte is 0.05M LiClO4 and 0.05M ferrocene in ?-butyrolactone and the

  8. A cubic boron nitride film-based fluorescent sensor for detecting Hg2+

    NASA Astrophysics Data System (ADS)

    Liu, W. M.; Zhao, W. W.; Zhang, H. Y.; Wang, P. F.; Chong, Y. M.; Ye, Q.; Zou, Y. S.; Zhang, W. J.; Zapien, J. A.; Bello, I.; Lee, S. T.

    2009-05-01

    Cubic boron nitride (cBN) film-based sensors for detecting Hg2+ ions were developed by surface functionalization with dansyl chloride. To immobilize dansyl chloride, 3-aminopropyltriethoxy silane was modified on hydroxylated cBN surfaces to form an amino-group-terminated self-assembled monolayer. The covalent attachment of the amino groups was confirmed by x-ray photoelectron spectroscopy. The selectivity and sensitivity of the sensors to detect diverse metal cations in ethanol solutions were studied by using fluorescence spectroscopy, revealing a great selectivity to Hg2+ ions. Significantly, the dansyl-chloride-functionalized cBN film sensors were recyclable after the sensing test.

  9. High Temperature - Thin Film Strain Gages Based on Alloys of Indium Tin Oxide

    NASA Technical Reports Server (NTRS)

    Gregory, Otto J.; Cooke, James D.; Bienkiewicz, Joseph M.

    1998-01-01

    A stable, high temperature strain gage based on reactively sputtered indium tin oxide (ITO) was demonstrated at temperatures up to 1050 C. These strain sensors exhibited relatively large, negative gage factors at room temperature and their piezoresistive response was both linear and reproducible when strained up to 700 micro-in/in. When cycled between compression and tension, these sensors also showed very little hysteresis, indicating excellent mechanical stability. Thin film strain gages based on selected ITO alloys withstood more than 50,000 strain cycles of +/- 500 micro-in/in during 180 hours of testing in air at 1000 C, with minimal drift at temperature. Drift rates as low as 0.0009%/hr at 1000 C were observed for ITO films that were annealed in nitrogen at 700 C prior to strain testing. These results compare favorably with state of the art 10 micro-m thick PdCr films deposited by NASA, where drift rates of 0.047%/hr at 1050 C were observed. Nitrogen annealing not only produced the lowest drift rates to date, but also produce the largest dynamic gage factors (G = 23.5). These wide bandgap, semiconductor strain sensors also exhibited moderately low temperature coefficients of resistance (TCR) at temperatures up to 1100 C, when tested in a nitrogen ambient. A TCR of +230 ppm/C over the temperature range 200 C < T < 500 C and a TCR of -469 ppm/C over the temperature range 600 C < T < 1100 C was observed for the films tested in nitrogen. However, the resistivity behavior changed considerably when the same films were tested in oxygen ambients. A TCR of -1560 ppm/C was obtained over the temperature range of 200 C < T < 1100 C. When similar films were protected with an overcoat or when ITO films were prepared with higher oxygen contents in the plasma, two distinct TCR's were observed. At T < 800 C, a linear TCR of -210 ppm/C was observed and at T > 800 C, a linear TCR of -2170 DDm/C was observed. The combination of a moderately low TCR and a relatively large gage factor make these semiconducting oxide films promising candidates for the active strain elements in high temperature thin film strain gages, particularly in applications where static strain measurement is desired.

  10. Formulation and in vitro characterization of novel sildenafil citrate-loaded polyvinyl alcohol-polyethylene glycol graft copolymer-based orally dissolving films.

    PubMed

    Xu, Li-Li; Shi, Li-Li; Cao, Qing-Ri; Xu, Wei-Juan; Cao, Yue; Zhu, Xiao-Yin; Cui, Jing-Hao

    2014-10-01

    This work was aimed to develop novel sildenafil citrate (SC)-loaded polyvinyl alcohol (PVA)-polyethylene glycol (PEG) graft copolymer (Kollicoat(®) IR)-based orally dissolving films (ODFs) using a solvent casting method. Formulation factors such as plasticizers and disintegrants were optimized on the basis of characteristics of blank ODFs. The SC-loaded ODF with a loading capacity up to 6.25mg in an area of 6 cm(2) was prepared and evaluated in terms of mechanical properties, disintegration time and dissolution rate. The physicochemical properties of drug-loaded ODF were also investigated using the scanning electron microscope (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). The blank ODF composed of Kollicoat(®) IR, sodium alginate (ALG-Na) and glycerol (10:2:1.5, w/w) had a remarkably short disintegration time of about 20s. The SC-loaded ODF showed a delayed disintegration time (about 25s), but exhibited improved mechanical properties when compared to the blank ODF. SC was homogeneously dispersed throughout the ODF and the crystalline form of drug had been partly changed, existing strong hydrogen bonding between the drug and carriers. The Kollicoat(®) IR/ALG-Na based ODFs containing SC might be an alternative to conventional tablet for the treatment of male erectile dysfunction. PMID:25079431

  11. Effect of a buffer layer on the properties of UV photodetectors based on a ZnO/diamond film structure

    NASA Astrophysics Data System (ADS)

    Huang, Jian; Wang, Linjun; Xu, Run; Shi, Weimin; Xia, Yiben

    2008-12-01

    In this paper, ZnO films were grown on the nucleation sides of freestanding diamond substrates with and without a ZnO homobuffer layer by the radio-frequency (RF) magnetron sputtering method. The effects of buffer layers on the properties of the ZnO film and UV photodetectors based on a ZnO/freestanding diamond film structure were studied. The experimental results suggested that the buffer layer was helpful in improving the crystalline quality of ZnO/diamond heteroepitaxial films and the electrical property of the ZnO photodetectors was relative to the crystalline quality of ZnO films. For the photodetector based on the ZnO film with a buffer layer, a higher value of photo-responsivity under a 10 V bias voltage and a better time-dependent photocurrent characteristic were obtained.

  12. Nanobiohybrid structures based on the organized films of photosensitive membrane proteins

    NASA Astrophysics Data System (ADS)

    Zaitsev, S. Yu; Solovyeva, D. O.; Nabiev, I. R.

    2014-01-01

    The fundamental principles and technologies for the design of stable film systems based on biomembranes, photosensitive membrane proteins and complexes (retinal-containing proteins, reaction centres of photosynthetic bacteria, light-harvesting complexes of photosystems I and II), including their associates with metal and metal oxide nanoparticles or quantum dots are described. The advantages of controlled incorporation of the semiconductor or plasmonic nanocrystals into the biohybrid film structures are analyzed, first of all, the increase in the wavelength range of solar light harvesting and effective transfer of collected energy to the biological chromophores. Particular attention is devoted to the production of ultrathin and highly organized films at interfaces as the key stage of the design of nanobiohybrid materials with particular properties for photovoltaics, optoelectronics and nanophotonics. The bibliography includes 182 references.

  13. Opto-electrical characterization of infrared sensors based on carbon nanotube films

    NASA Astrophysics Data System (ADS)

    Koechlin, Charlie; Maine, Sylvain; Rennesson, Stéphanie; Haidar, Riad; Trétout, Brigitte; Loiseau, Annick; Pelouard, Jean-Luc

    2010-06-01

    A large array of devices based on a carbon nanotubes film was realized. Electrical characterization by the transfer length method enables the determination of the sheet resistance, and contact resistance, which is extremely low. The resistance dispersion is shown to be due to the film non-uniformity, and is low enough to enable the realization of bolometer focal plane arrays. A decrease of the resistance with the temperature is observed and leads to a TCR of -0.2%K. The strong absorption of carbon nanotubes films in the mid infrared transmission band (3-5 ?m and of 8-14 ?m) enables us to demonstrate the first carbon nanotubes photo response for these wavelengths.

  14. K-Band Reflectarray Antenna Based on Ferroelectric Thin Films: What Have We Learned so Far

    NASA Technical Reports Server (NTRS)

    Miranda, Felix A.; Romanofsky, Robert; Mueller, Carl H.; VanKeuls, Fred

    2002-01-01

    The Applied RF Technology Branch of the NASA Glenn Research Center, Cleveland, Ohio, has an on-going effort in the area of thin film ferroelectric technology for microwave applications. Particular attention has been given to developing ferroelectric phase shifters for the implementation and experimental demonstration of an electronically steerable reflectarray antenna. In the process of optimizing these material to fit the implementation requirements of the aforementioned antenna, we have accumulated a great deal of information and knowledge in areas such as the effect of the composition of the ferroelectric thin films on phase shifter performance, self assembled monolayers (SAMs) in the metallic/ferroelectric interface and their impact on phase shifter performance, correlation between microstructure and microwave properties, and the effect of selective etching on the overall performance of a thin film-ferroelectric based microwave component, amongst others. We will discuss these issues and will provide an up-dade of the current development status of the reflect-array antenna.

  15. Impermeable barrier films and protective coatings based on reduced graphene oxide

    NASA Astrophysics Data System (ADS)

    Su, Y.; Kravets, V. G.; Wong, S. L.; Waters, J.; Geim, A. K.; Nair, R. R.

    2014-09-01

    Flexible barrier films preventing permeation of gases and moistures are important for many industries ranging from food to medical and from chemical to electronic. From this perspective, graphene has recently attracted particular interest because its defect-free monolayers are impermeable to all atoms and molecules. However, it has been proved to be challenging to develop large-area defectless graphene films suitable for industrial use. Here we report barrier properties of multilayer graphitic films made by gentle chemical reduction of graphene oxide laminates with hydroiodic and ascorbic acids. They are found to be highly impermeable to all gases, liquids and aggressive chemicals including, for example, hydrofluoric acid. The exceptional barrier properties are attributed to a high degree of graphitization of the laminates and little structural damage during reduction. This work indicates a close prospect of graphene-based flexible and inert barriers and protective coatings, which can be of interest for numerous applications.

  16. Base and acid treatment of SWCNT-RNA transparent conductive films.

    PubMed

    Wang, Ranran; Sun, Jing; Gao, Lian; Zhang, Jing

    2010-08-24

    RNA was used to exfoliate single-walled carbon nanotubes (SWCNTs) in aqueous solution, and the ratio of it was optimized to obtain the best dispersion state. The obtained homogeneous SWCNT solution with small bundle size was used to prepare flexible transparent conductive films by filtration method. Sodium hydroxide treatment combining short-time acid treatment was used to remove the RNA molecules. After treatment, the sheet resistance of the films decreased significantly, while the change on the transmittance was negligible. Besides, the polyethylene terephthalate substrate would not turn brittle through this treatment process. Flexible films with outstanding performance (190 Omega/sq, 85%) and good stability were obtained after treatment. X-ray photoelectron spectroscopy and scanning electron microscope were used to analyze the role of base and acid treatment in detail. PMID:20731462

  17. Laser-based diagnostics for the measurement of liquid water film thickness.

    PubMed

    Greszik, Daniel; Yang, Huinan; Dreier, Thomas; Schulz, Christof

    2011-02-01

    Three different diagnostic techniques are investigated for measurement of the thickness of liquid water films deposited on a transparent quartz plate. The methods are based on laser-induced fluorescence (LIF) from low concentrations of a dissolved tracer substance and spontaneous Raman scattering of liquid water, respectively, both excited with 266?nm of radiation, and diode laser absorption spectroscopy (DLAS) in the near-infrared spectral region. Signal intensities are calibrated using liquid layers of known thickness between 0 and 1000??m. When applied to evaporating liquid water films, the thickness values derived from the direct DLAS and Raman scattering measurements correlate well with each other as a function of time after the start of data recording, while the LIF signal derived thickness values decrease faster with time due to selective tracer evaporation from the liquid. The simultaneous application of the LIF with a tracer-free detection technique can serve as an in situ reference for quantitative film thickness measurements. PMID:21283221

  18. Localized and distributed mass detectors with high sensitivity based on thin-film bulk acoustic resonators

    NASA Astrophysics Data System (ADS)

    Campanella, Humberto; Esteve, Jaume; Montserrat, Josep; Uranga, Arantxa; Abadal, Gabriel; Barniol, Nuria; Romano-Rodríguez, Albert

    2006-07-01

    A mass sensor based on thin-film bulk acoustic resonator, intended for biomolecular applications, is presented. The thin film is a (002) AlN membrane, sputtered over Ti /Pt on a (001) Si wafer, and released by surface micromachining of silicon. Two experiments are proposed to test the mass sensing performance of the resonators: (a) distributed loading with a MgF2 film by means of physical vapor deposition and (b) localized mass growing of a C /Pt/Ga composite using focused-ion-beam-assisted deposition, both on the top electrode. For the distributed and localized cases, the minimum detectable mass changes are 1.58×10-8g/cm2 and 7×10-15g, respectively.

  19. Constructivist Learning of Anatomy: Gaining Knowledge by Creating Anatomical Casts

    NSDL National Science Digital Library

    Heidi L. Lujan (Wayne State Univ Sch Med Dept of Physiology)

    2011-03-01

    This article describes a method to promote inquiry based learning in the anatomy curriculum. The article describes a method requiring students to build casts of the bronchial tree and coronary arteries while faculty asked leading questions related to the material.

  20. Transglutaminase crosslinked pectin- and chitosan-based edible films: a review.

    PubMed

    Porta, Raffaele; Mariniello, Loredana; Di Pierro, Prospero; Sorrentino, Angela; Giosafatto, Concetta Valeria L

    2011-03-01

    The production of biodegradable and edible films with desired mechanical characteristics and gas barrier properties represents one of the most advanced challenges in the field of food wrapping and coating. New edible films can serve not only to provide food with physical protection but also to reduce loss of their moisture, to restrict absorption of oxygen, to lessen migration of lipids, to improve their mechanical handling features, and as materials, to apply in direct contact with internal food to realize a multilayer food packaging. Polymers derived from natural products, like carbohydrates and proteins, offer the greatest opportunities as component of edible films since their biodegradability and environmental compatibility are assured and they can also supplement the nutritional value of specific foods. However, excessive water solubility and poor water vapor barrier properties, and often poor mechanical resistance, have their application limited until the present time. Numerous studies have been carried out to improve their properties by preparing composite and multi-component films or by physically and chemically crosslinking their natural components. In the present review we summarize the main results obtained by crosslinking with the enzyme transglutaminase different proteins contained in multi-component pectin- and chitosan-based edible films, having the aim to create environmentally-friendly "bioplastics" with mechanical and permeability properties similar to the ones exhibited by plastics of petrochemical origin. PMID:21390943