Science.gov

Sample records for based cast films

  1. Cast aluminum denture base.

    PubMed

    Barco, M T; Dembert, M L

    1987-08-01

    The laboratory procedures for a cast aluminum base denture have been presented. If an induction casting machine is not available, the "two-oven technique" works well, provided the casting arm is kept spinning manually for 4 minutes after casting. If laboratory procedures are executed precisely and with care, the aluminum base denture can be cast with good results. PMID:3305884

  2. Vacuum casting of thick polymeric films

    NASA Technical Reports Server (NTRS)

    Cuddihy, E. F.; Moacanin, J.

    1979-01-01

    Bubble formation and layering, which often plague vacuum-evaporated films, are prevented by properly regulating process parameters. Vacuum casting may be applicable to forming thick films of other polymer/solvent solutions.

  3. A simple calibration approach based on film-casting for confocal Raman microscopy to support the development of a hot-melt extrusion process.

    PubMed

    Netchacovitch, L; Thiry, J; De Bleye, C; Dumont, E; Dispas, A; Hubert, C; Krier, F; Sacré, P-Y; Evrard, B; Hubert, Ph; Ziemons, E

    2016-07-01

    When developing a new formulation, the development, calibration and validation steps of analytical methods based on vibrational spectroscopy are time-consuming. For each new formulation, real samples must be produced and a "reference method" must be used in order to determine the Active Pharmaceutical Ingredient (API) content of each sample. To circumvent this issue, the paper presents a simple approach based on the film-casting technique used as a calibration tool in the framework of hot-melt extrusion process. Confocal Raman microscopic method was successfully validated for the determination of itraconazole content in film-casting samples. Then, hot-melt extrusion was carried out to produce real samples in order to confront the results obtained with confocal Raman microscopy and Ultra High Performance Liquid Chromatography (UHPLC). The agreement between both methods was demonstrated using a comparison study based on the Bland and Altman's plot. PMID:27154691

  4. Tuning the properties of polyhydroxybutyrate films using acetic acid via solvent casting

    NASA Astrophysics Data System (ADS)

    Anbukarasu, Preetam; Sauvageau, Dominic; Elias, Anastasia

    2015-12-01

    Biodegradable polyhydroxybutyrate (PHB) films were fabricated using acetic acid as an alternative to common solvents such as chloroform. The PHB films were prepared using a solvent casting process at temperatures ranging from 80 °C to 160 °C. The crystallinity, mechanical properties and surface morphology of the films cast at different temperatures were characterized and compared to PHB films cast using chloroform as a solvent. Results revealed that the properties of the PHB film varied considerably with solvent casting temperature. In general, samples processed with acetic acid at low temperatures had comparable mechanical properties to PHB cast using chloroform. This acetic acid based method is environmentally friendly, cost efficient and allows more flexible processing conditions and broader ranges of polymer properties than traditional methods.

  5. Tuning the properties of polyhydroxybutyrate films using acetic acid via solvent casting

    PubMed Central

    Anbukarasu, Preetam; Sauvageau, Dominic; Elias, Anastasia

    2015-01-01

    Biodegradable polyhydroxybutyrate (PHB) films were fabricated using acetic acid as an alternative to common solvents such as chloroform. The PHB films were prepared using a solvent casting process at temperatures ranging from 80 °C to 160 °C. The crystallinity, mechanical properties and surface morphology of the films cast at different temperatures were characterized and compared to PHB films cast using chloroform as a solvent. Results revealed that the properties of the PHB film varied considerably with solvent casting temperature. In general, samples processed with acetic acid at low temperatures had comparable mechanical properties to PHB cast using chloroform. This acetic acid based method is environmentally friendly, cost efficient and allows more flexible processing conditions and broader ranges of polymer properties than traditional methods. PMID:26640089

  6. Fractal structures in casting films from chlorophyll

    NASA Astrophysics Data System (ADS)

    Pedro, G. C.; Gorza, F. D. S.; de Souza, N. C.; Silva, J. R.

    2014-04-01

    Chlorophyll (Chl) molecules are important because they can act as natural light-harvesting devices during the photosynthesis. In addition, they have potential for application as component of solar cell. In this work, we have prepared casting films from chlorophyll (Chl) and demonstrated the occurrence of fractal structures when the films were submitted to different concentrations. By using optical microscopy and the box-count method, we have found that the fractal dimension is Df = 1.55. This value is close to predicted by the diffusion-limited aggregation (DLA) model. This suggests that the major mechanism - which determines the growth of the fractal structures from Chl molecules - is the molecular diffusion. Since the efficiencies of solar cells depend on the morphology of their interfaces, these finds can be useful to improve this kind of device.

  7. Melting and casting of FeAl-based cast alloy

    SciTech Connect

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

    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.

  8. Residual stress in spin-cast polyurethane thin films

    NASA Astrophysics Data System (ADS)

    Zhang, Hong; Zhang, Li

    2015-01-01

    Residual stress is inevitable during spin-casting. Herein, we report a straightforward method to evaluate the residual stress in as-cast polyurethane thin films using area shrinkage measurement of films in floating state, which shows that the residual stress is independent of radial location on the substrate and decreased with decreasing film thickness below a critical value. We demonstrate that the residual stress is developed due to the solvent evaporation after vitrification during spin-casting and the polymer chains in thin films may undergo vitrification at an increased concentration. The buildup of residual stress in spin-cast polymer films provides an insight into the size effects on the nature of polymer thin films.

  9. Residual stress in spin-cast polyurethane thin films

    SciTech Connect

    Zhang, Hong; Zhang, Li

    2015-01-19

    Residual stress is inevitable during spin-casting. Herein, we report a straightforward method to evaluate the residual stress in as-cast polyurethane thin films using area shrinkage measurement of films in floating state, which shows that the residual stress is independent of radial location on the substrate and decreased with decreasing film thickness below a critical value. We demonstrate that the residual stress is developed due to the solvent evaporation after vitrification during spin-casting and the polymer chains in thin films may undergo vitrification at an increased concentration. The buildup of residual stress in spin-cast polymer films provides an insight into the size effects on the nature of polymer thin films.

  10. Emulsion based cast booster - a priming system

    SciTech Connect

    Gupta, R.N.; Mishra, A.K.

    2005-07-01

    This paper explores the potential of emulsion based cast booster to be used as primer to initiate bulk delivered emulsion explosives used in mines. An attempt has been made for comparative study between conventional cast booster and emulsion based cast booster in terms of the initiation process developed and their capability to develop and maintain the stable detonation process in the column explosives. The study has been conducted using a continuous velocity of detonation (VOD) measuring instrument. During this study three blasts have been monitored. In each blast two holes have been selected for study, the first hole being initiated with conventional cast booster while the other one with emulsion based cast booster. The findings of the study advocates that emulsion based cast booster is capable of efficient priming of bulk delivered column explosive with stable detonation process in the column. Further, the booster had advantages over the conventional PETN/TNT based cast booster. 5 refs., 2 figs., 1 tab., 1 photo.

  11. Bifilm Defects in Ni-Based Alloy Castings

    NASA Astrophysics Data System (ADS)

    Campbell, John; Tiryakioğlu, Murat

    2012-08-01

    The Ni-base superalloys, which are normally melted and cast in a vacuum, entrain their surface-oxide film during turbulent pouring of the melt; unfortunately at this time, this process is universally practiced for investment castings of these materials. The entrained film becomes a bifilm crack automatically, so that cast alloys have a large population of cracks that controls their failure behavior. The problems of the growth of single crystals and the welding of polycrystalline alloys are reviewed to illustrate the central role of bifilms in the cracking of turbine blades, the heat-affected zones of welds, and the reliability of properties. It has been demonstrated that improved gravity pouring systems can reduce these problems significantly, but only countergravity filling of molds is expected to result in defect-free castings. Recent cases in which turbine blades failed in service are examined, and the central role of bifilm defects in these failures is discussed.

  12. 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

  13. Starch-polyvinyl alcohol cast film-performance and biodegradation

    SciTech Connect

    Chen, Liang; Imam, S.H.; Stein, T.M.

    1996-10-01

    Starch-polyvinyl alcohol (PVOH) cast films were prepared in the absence of plasticizer. Their physical and biodegradable properties were examined. Moisture absorption by the films was similar to that of PVOH at low humidity and increased linearly as the relative humidity increased. The tensile strength of the films decreased with increased humidity and did not display significant improvement with increased PVOH content. Higher PVOH content improved elongation when the relative humidity was 80% or higher. Biodegradation studies revealed that the presence of PVOH in the films slowed the rate of degradation.

  14. Electrospun fiber and cast films produced using zein blends with nylon-6

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Blends of zein and nylon-6 (55k) were used to produce electrospun fibers and solution cast films. Zein was blended with nylon-6 in formic acid solution. When the amount of nylon-6 was 8% or less a compatible blend formed. The blend was determined to be compatible based on physical property measureme...

  15. 3D Freeze-Casting of Cellular Graphene Films for Ultrahigh-Power-Density Supercapacitors.

    PubMed

    Shao, Yuanlong; El-Kady, Maher F; Lin, Cheng-Wei; Zhu, Guanzhou; Marsh, Kristofer L; Hwang, Jee Youn; Zhang, Qinghong; Li, Yaogang; Wang, Hongzhi; Kaner, Richard B

    2016-08-01

    3D cellular graphene films with open porosity, high electrical conductivity, and good tensile strength, can be synthesized by a method combining freeze-casting and filtration. The resulting supercapacitors based on 3D porous reduced graphene oxide (RGO) film exhibit extremely high specific power densities and high energy densities. The fabrication process provides an effective means for controlling the pore size, electronic conductivity, and loading mass of the electrode materials, toward devices with high energy-storage performance. PMID:27214752

  16. 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 ...

  17. Tape casting and partial melting of Bi-2212 thick films

    NASA Technical Reports Server (NTRS)

    Buhl, D.; Lang, TH.; Heeb, B.; Gauckler, L. J.

    1995-01-01

    To produce Bi-2212 thick films with high critical current densities tape casting and partial melting is a promising fabrication method. Bi-2212 powder and organic additives were mixed into a slurry and tape casted onto glass by the doctor blade tape casting process. The films were cut from the green tape and partially molten on Ag foils during heat treatment. We obtained almost single-phase and well-textured films over the whole thickness of 20 microns. The orientation of the (a,b)-plane of the grains was parallel to the substrate with a misalignment of less than 6 deg. At 77 K/0T a critical current density of 15, 000 A/sq cm was reached in films of the dimension 1 cm x 2 cm x 20 microns (1 micron V/cm criterion, resistively measured). At 4 K/0T the highest value was 350,000 A/sq cm (1 nV/cm criterion, magnetically measured).

  18. Tape casting and partial melting of Bi-2212 thick films

    SciTech Connect

    Buhl, D.; Lang, T.; Heeb, B.

    1994-12-31

    To produce Bi-2212 thick films with high critical current densities tape casting and partial melting is a promising fabrication method. Bi-2212 powder and organic additives were mixed into a slurry and tape casted onto glass by the doctor blade tape casting process. The films were cut from the green tape and partially molten on Ag foils during heat treatment. We obtained almost single-phase and well-textured films over the whole thickness of 20 {mu}m. The orientation of the (a,b)-plane of the grains were parallel to the substrate with a misalignment of less than 6{degrees}. At 77K/OT a critical current density of 15`000 A/cm{sup 2} was reached in films of the dimension 1cm x 2cm x 20{mu}m (1{mu}V/cm criterion, resistively measured). At 4K/OT the highest value was 350`000 A/cm{sup 2} (1nV/cm criterion, magnetically measured).

  19. 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

  20. Land-based turbine casting initiative

    SciTech Connect

    Mueller, B.A.; Spicer, R.A.

    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.

  1. Study of anisotropy of spin cast and vapor deposited polyimide films using internal reflection techniques

    SciTech Connect

    Liberman, V.

    1996-11-01

    We have compared anisotropy of spin cast and vapor deposited polyimide (VDP) films, using internal reflection infrared spectroscopy. The films were deposited directly on the internal reflection element. We find that spin cast films are more anisotropic than their VDP counterparts, with the polyimide chains tending to align parallel to the substrate. Both films are found to contain more and less ordered regions. Within the ordered regions, the plane of the phenyl ring tends to align parallel to the substrate.

  2. Fabrication of silk fibroin film using centrifugal casting technique for corneal tissue engineering.

    PubMed

    Lee, Min Chae; Kim, Dong-Kyu; Lee, Ok Joo; Kim, Jung-Ho; Ju, Hyung Woo; Lee, Jung Min; Moon, Bo Mi; Park, Hyun Jung; Kim, Dong Wook; Kim, Su Hyeon; Park, Chan Hum

    2016-04-01

    Films prepared from silk fibroin have shown potential as biomaterials in tissue engineering applications for the eye. Here, we present a novel process for fabrication of silk fibroin films for corneal application. In this work, fabrication of silk fibroin films was simply achieved by centrifugal force. In contrast to the conventional dry casting method, we carried out the new process in a centrifuge with a rotating speed of 4000 rpm, where centrifugal force was imposed on an aluminum tube containing silk fibroin solution. In the present study, we also compared the surface roughness, mechanical properties, transparency, and cell proliferation between centrifugal and dry casting method. In terms of surface morphology, films fabricated by the centrifugal casting have less surface roughness than those by the dry casting. For elasticity and transparency, silk fibroin films obtained from the centrifugal casting had favorable results compared with those prepared by dry casting. Furthermore, primary human corneal keratocytes grew better in films prepared by the centrifugal casting. Therefore, our results suggest that this new fabrication process for silk fibroin films offers important potential benefits for corneal tissue regeneration. PMID:25939800

  3. Ink-jet printing versus solvent casting to prepare oral films: Effect on mechanical properties and physical stability.

    PubMed

    Buanz, Asma B M; Belaunde, Claudia C; Soutari, Nina; Tuleu, Catherine; Gul, Mine Orlu; Gaisford, Simon

    2015-10-30

    The aim of this work was to compare and contrast the mechanical properties and physical stabilities of oral films prepared with either thermal ink-jet printing (TIJP) or solvent casting (SC). Clonidine hydrochloride was selected as a model drug because of its low therapeutic dose and films were prepared using cellulose polymers. Mechanical testing showed that the printed films had Young's moduli and tensile strength values similar to the free film, while casted films were significantly more brittle. The drug also appeared to crystallize out of casted films during stress testing whereas printed films remained unchanged. The dissolution behavior of printed and cast films were similar, because of the rapid disintegration of the polymer. The conclusion is that printing resulted in a better film than casting because the drug resided on the film, rather than in the film where it could exert a plasticizing effect. PMID:25526674

  4. 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.

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

    SciTech Connect

    Mehtani, Hitesh Kumar Kumar, Rishi Raina, K. K.

    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 β phase was ensured in spin cast PVDF film by the FTIR spectroscopy. The β phase is very important in the application because it improve the properties like piezoelectricity by modifying PVDF crystallinity.

  6. Storage stability and antibacterial activity against Escherichia coli O157:H7 of carvacrol in edible apple films made by two different casting methods.

    PubMed

    Du, Wen-Xian; Olsen, Carl W; Avena-Bustillos, Roberto J; McHugh, Tara H; Levin, Carol E; Friedman, Mendel

    2008-05-14

    The antimicrobial activities against Escherichia 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 assays of films and high-performance liquid chromatography (HPLC) analysis of film extracts following storage up to 49 days at 5 and 25 degrees C revealed that (a) optimum antimicrobial effects were apparent with carvacrol levels of approximately 1.0% added to the purees prior to film preparation, (b) carvacrol in the films and film weights remained unchanged over the storage period of up to 7 weeks, and (c) casting methods affected carvacrol concentration, bactericidal activity, physicochemical properties, and colors of the apple films. Carvacrol addition to the purees used to prepare the films reduced water vapor and oxygen permeability of apple films. The results indicate that carvacrol has a dual benefit. It can be used to both impart antimicrobial activities and enhance barrier properties of edible films. The cited observations facilitate relating compositional and physicochemical properties of apple puree films containing volatile plant antimicrobials to their use in foods. PMID:18366181

  7. 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, ...

  8. Microporosity Prediction and Validation for Ni-based Superalloy Castings

    NASA Astrophysics Data System (ADS)

    Guo, J.; Beckermann, C.; Carlson, K.; Hirvo, D.; Bell, K.; Moreland, T.; Gu, J.; Clews, J.; Scott, S.; Couturier, G.; Backman, D.

    2015-06-01

    Microporosityin high performance aerospace castings can reduce mechanical properties and consequently degrade both component life and durability. Therefore, casting engineers must be able to both predict and reduce casting microporosity. A dimensionless Niyama model has been developed [1] that predicts local microporosity by accounting for local thermal conditions during casting as well as the properties and solidification characteristics of the cast alloy. Unlike the well-known Niyama criterion, application of the dimensionless Niyama model avoids the need to find a threshold Niyama criterion below which shrinkage porosity forms - a criterion which can be determined only via extensive alloy dependent experimentation. In the present study, the dimensionless Niyama model is integrated with a commercial finite element casting simulation software, which can now more accurately predict the location-specific shrinkage porosity volume fraction during solidification of superalloy castings. These microporosity predictions are validated by comparing modelled results against radiographically and metallographically measured porosity for several Ni-based superalloy equiaxed castings that vary in alloy chemistry with a focus on plates of changing draft angle and thickness. The simulation results agree well with experimental measurements. The simulation results also show that the dimensionless Niyama model can not only identify the location but also the average volume fraction of microporosity distribution in these equiaxed investment cast Ni-based superalloy experiments of relatively simple geometry.

  9. 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.

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

    NASA Astrophysics Data System (ADS)

    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.

    2015-07-01

    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.

  11. 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

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

    PubMed Central

    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

  13. Antimicrobial Activity of Nisin and Natamycin Incorporated Sodium Caseinate Extrusion-Blown Films: A Comparative Study with Heat-Pressed/Solution Cast Films.

    PubMed

    Colak, Basak Yilin; Peynichou, Pierre; Galland, Sophie; Oulahal, Nadia; Prochazka, Frédéric; Degraeve, Pascal

    2016-05-01

    Antimicrobial edible films based on sodium caseinate, glycerol, and 2 food preservatives (nisin or natamycin) were prepared by classical thermomechanical processes. Food preservatives were compounded (at 65 °C for 2.5 min) with sodium caseinate in a twin-screw extruder. Anti-Listeria activity assays revealed a partial inactivation of nisin following compounding. Thermoplastic pellets containing food preservatives were then used to manufacture films either by blown-film extrusion process or by heat-press. After 24 h of incubation on agar plates, the diameters of K. rhizophila growth inhibition zones around nisin-incorporated films prepared by solution casting (control), extrusion blowing or heat pressing at 80 °C for 7 min of nisin-containing pellets were 15.5 ± 0.9, 9.8 ± 0.2, and 8.6 ± 1.0 mm, respectively. Since heat-pressing for 7 min at 80 °C of nisin-incorporated pellets did not further inactivate nisin, this indicates that nisin inactivation during extrusion-blowing was limited. Moreover, the lower diameter of the K. rhizophila growth inhibition zone around films prepared with nisin-containing pellets compared to that observed around films directly prepared by solution casting confirms that nisin inactivation mainly occurred during the compounding step. Natamycin-containing thermoplastic films inhibited Aspergillus niger growth; however, by contrast with nisin-containing films, heat-pressed films had higher inhibition zone diameters than blown films, therefore suggesting a partial inactivation of natamycin during extrusion-blowing. PMID:27061434

  14. 25. Detail of cast iron lamp post base with fluted ...

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

    25. Detail of cast iron lamp post base with fluted wooded post at top, located at north end of bridge. VIEW NORTHEAST - Chelsea Street Bridge & Draw Tender's House, Spanning Chelsea River, Boston, Suffolk County, MA

  15. DETAIL VIEW OF BASE OF CAST IRON TOWER SHOWING THE ...

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

    DETAIL VIEW OF BASE OF CAST IRON TOWER SHOWING THE FABRICATING MARK OF STARBUCK IRON WORKS, TROY, NY - Bidwell Bar Suspension Bridge & Stone Toll House, Near Lake Oroville (moved from fork of Feather River), Oroville, Butte County, CA

  16. 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

  17. Ultrasonically assisted single screw extrusion, film blowing and film casting of LLDPE/clay and PA6/clay nanocomposites

    NASA Astrophysics Data System (ADS)

    Niknezhad, Setareh

    The major objective of this study was to investigate the effect of ultrasonic treatment on the dispersion of modified clay particles in LLDPE and PA6 matrices and the final properties of nanocomposites. LLDPE and PA6 are two polymers that are widely used in packaging industry. Blown and cast films were manufactured from the prepared nanocomposites. To achieve one step film processing, an online ultrasonic film casting was developed. Ultrasonic waves caused high-energy mixing and dispersion due to the acoustic cavitation, causing the clay agglomorates to separate into individual platelets in polymer matrix. Ultrasonic waves also broke down the polymer molecular chains reducing viscosity of the melt, facilating dispersion of the clay platelets throughout the matrix. Ultrasound also led to a breakage of the clay platelets reducing the particle size and improving their distribution. Clay particles acted as a heterogenous nucleation agent generating smaller size polymer crystals. In turn, these improved different properties including mechanical properties, oxygen permeability and transparency of films. In LLDPE/clay 20A nanocomposites, the effect of ultrasound was more obvious at higher clay loadings. Exfoliated structure for ultrasonically treated nanocomposites containing 2.5, 5 and 7.5 wt% of clay 20A and highly intercalated structure for ultrasonically treated nanocomposites containing 10 wt% of clay 20A were achieved. However, in blown films, the exfoliated structure transferred to the intercalated structure due to the addition of more shear and thermal degradation of surfactants of the clay particles. While, manufacturing cast films using the new developed online ultrasonic cast film machine revealed the exfoliated structure with ultrasonic treatment till 7.5 wt% of clay loadings. Cast films of nanocomposites containing 5 wt% of clay loadings were also prepared with addition of different compatibilizers. The compatibilizer containing higher amount of grafted

  18. Conductivity of PEDOT:PSS on Spin-Coated and Drop Cast Nanofibrillar Cellulose Thin Films

    NASA Astrophysics Data System (ADS)

    Valtakari, Dimitar; Liu, Jun; Kumar, Vinay; Xu, Chunlin; Toivakka, Martti; Saarinen, Jarkko J.

    2015-10-01

    Aqueous dispersion of conductive polymer poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT:PSS) was deposited on spin-coated and drop cast nanofibrillar cellulose (NFC)-glycerol (G) matrix on a glass substrate. A thin glycerol film was utilized on plasma-treated glass substrate to provide adequate adhesion for the NFC-glycerol (NFC-G) film. The effects of annealing temperature, the coating method of NFC-G, and the coating time intervals on the electrical performance of the PEDOT:PSS were characterized. PEDOT:PSS on drop cast NFC-G resulted in 3 orders of magnitude increase in the electrical conductivity compared to reference PEDOT:PSS film on a reference glass substrate, whereas the optical transmission was only slightly decreased. The results point out the importance of the interaction between the PEDOT:PSS and the NFC-G for the electrical and barrier properties for thin film electronics applications.

  19. Inhibition of postsurgical adhesions by methylene blue-loaded nanofibers versus cast film matrices.

    PubMed

    El-Sayed, Nesma; Galal, Sally; El-Gowelli, Hanan; El-Khordagui, Labiba

    2016-07-01

    In the quest for barrier membranes for the prevention of post-surgical tissue adhesions, polymer matrices may provide a platform of biomaterials with versatile properties. However, the relationship between the anti-adhesion effects of different polymer matrices and their physicochemical and structural properties is not yet adequately understood. In a preclinical study using a rat cecum model, we directly compared the anti-adhesion potential of polyhydroxybutyrate (PHB) electrospun nanofibrous versus cast film matrices loaded with methylene blue (MB) as antioxidant adhesion inhibitor. PHB retained MB presumably forming MB-bioactivated matrices. In the preclinical study, quantitative morphologic assessment in addition to histopathologic and SEM examinations 14 days post-surgery indicated that plain PHB NFs and MB-PHB NFs, moderately enhanced cecal wall healing and inhibited adhesion formation. In contrast, reshaping PHB as cast films, significantly enhanced healing, reduced adhesion bands and prevented inter-visceral adhesions. Cast films also inhibited tissue attachment to the matrix recovered 14 days post-surgery. Both PHB matrix types reduced tissue inflammation. Despite tissue anti-adhesion potential of individual matrix components, modulation of the micro-architectural properties generated polymer barriers with varying tissue anti-adhesion and healing potentials, the MB-loaded cast film achieving the best outcome. PMID:27093975

  20. Surface dynamics of poly(methyl methacrylate) films affected by the concentration of casting solutions.

    PubMed

    Tian, Houkuan; Yang, Yuhui; Ding, Jia; Liu, Wanglong; Zuo, Biao; Yang, Juping; Wang, Xinping

    2014-09-01

    The effect of the concentration of casting solutions on the surface dynamics of the corresponding spin-coated poly(methyl methacrylate) (PMMA) film was investigated by measuring the surface reorganization of fluorine tracer-labeled PMMA. The onset temperature of fluorinated PMMA chain end reorganization (T(onsetR)) was identified and is shown to depend on the PMMA concentration in the film-forming solution. It was found that the surface T(onsetR) and relaxation activation energy E(a) of the PMMA films prepared from 4.2 wt% PMMA cyclohexanone solution are 70 °C and 260 kJ mol(-1), respectively, which are higher than those of the PMMA films prepared from 0.8 wt% PMMA cyclohexanone solution (55 °C and 144 kJ mol(-1), respectively). The T(onsetR) and E(a) of PMMA films increased with increasing concentration of casting solutions within the range of 1.8 wt% to 4 wt%. The chain entanglement of PMMA chains is proposed to be the speculative origin for these observed depressed dynamics of poly(methyl methacrylate) chains on the films' surface prepared using casting solutions of various concentrations. PMID:25036734

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

    SciTech Connect

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

    2015-05-22

    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 al{sup 1} 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.{sup 1}D. Silagy, Y. Demay, and J-F. Agassant, Polym. Eng. Sci., 36, 2614 (1996)

  2. Awareness Programs and Change in Taste-Based Caste Prejudice

    PubMed Central

    Banerjee, Ritwik; Datta Gupta, Nabanita

    2015-01-01

    Becker's theory of taste-based discrimination predicts that relative employment of the discriminated social group will improve if there is a decrease in the level of prejudice for the marginally discriminating employer. In this paper we experimentally test this prediction offered by Garry Becker in his seminal work on taste based discrimination, in the context of caste in India, with management students (potential employers in the near future) as subjects. First, we measure caste prejudice and show that awareness through a TV social program reduces implicit prejudice against the lower caste and the reduction is sustained over time. Second, we find that the treatment reduces the prejudice levels of those in the left tail of the prejudice distribution - the group which can potentially affect real outcomes as predicted by the theory. And finally, a larger share of the treatment group subjects exhibit favorable opinion about reservation in jobs for the lower caste. PMID:25902290

  3. Functional properties of chitosan-based films.

    PubMed

    Leceta, I; Guerrero, P; de la Caba, K

    2013-03-01

    Chitosan-based films plasticized with glycerol were prepared by casting with the aim to obtain environmentally friendly materials for packaging applications. Different contents of glycerol were incorporated into chitosan solutions to improve mechanical properties and all films obtained were flexible and transparent. It was observed that the transparency and good behaviour of the films against UV radiation were not affected by chitosan molecular weight or glycerol content. Moreover, chitosan-based films exhibited excellent barrier properties against water vapour and oxygen, even with the addition of glycerol. The effect of the plasticizer on the properties has been explained using Fourier transform infrared (FTIR) spectroscopic analysis. The changes observed in the intensity of the bands showed that glycerol interacts with chitosan, which could be confirmed by total soluble matter (TSM). PMID:23465939

  4. Comparison of directly compressed vitamin B12 tablets prepared from micronized rotary-spun microfibers and cast films.

    PubMed

    Sebe, István; Bodai, Zsolt; Eke, Zsuzsanna; Kállai-Szabó, Barnabás; Szabó, Péter; Zelkó, Romána

    2015-01-01

    Fiber-based dosage forms are potential alternatives of conventional dosage forms from the point of the improved extent and rate of drug dissolution. Rotary-spun polymer fibers and cast films were prepared and micronized in order to direct compress after homogenization with tabletting excipients. Particle size distribution of powder mixtures of micronized fibers and films homogenized with tabletting excipients were determined by laser scattering particle size distribution analyzer. Powder rheological behavior of the mixtures containing micronized fibers and cast films was also compared. Positron annihilation lifetime spectroscopy was applied for the microstructural characterization of micronized fibers and films. The water-soluble vitamin B12 release from the compressed tablets was determined. It was confirmed that the rotary spinning method resulted in homogeneous supramolecularly ordered powder mixture, which was successfully compressed after homogenization with conventional tabletting excipients. The obtained directly compressed tablets showed uniform drug release of low variations. The results highlight the novel application of micronized rotary-spun fibers as intermediate for further processing reserving the original favorable powder characteristics of fibrous systems. PMID:25190153

  5. Automated Quantitative Inspection Of Metal Castings From X-Ray Film Images

    NASA Astrophysics Data System (ADS)

    Tvirbutas, Andrew A.; McPherson, Charles A.

    1988-03-01

    An accepted and widely used method of inspecting cast metal parts involves a visual interpretation of X-ray film by a qualified radiographer. The defective areas of the cast-ing are compared to a set of reference standards, and a casting grade is assigned. This method of quality assessment is often to crude for modern applications. An automated inspection technique is presented which provides a quantitative assessment of casting qual-ity. The quantified results of the inspection are advantageous in providing information which can be used to establish an acceptance criterion that can be directly related to part performance. Careful control of geometry, exposure parameters, and inclusion of a calibration wedge during radiography enable calibrated, quantitative analysis of the defective area to be performed. Level preserved smoothing is introduced as a method of smoothing the digitized radiograph while retaining thickness calibration. This technique combined with region labeling, allows the x, y, and z dimensions of individual defects to be measured and defect statistics to be generated. A discussion of a CAD model data to reduce the number of required radiographic views of a part in accurate defect measurement is also pursued.

  6. 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

  7. Relationships between the solution and solid-state properties of solution-cast low-k silica thin films.

    PubMed

    Chiang, Chao-Ching; Su, Chien-You; Yang, An-Chih; Wang, Ting-Yu; Lee, Wen-Ya; Hua, Chi-Chung; Kang, Dun-Yen

    2016-07-27

    This paper reports on the fabrication of low-k (amorphous) silica thin films cast from solutions without and with two different types of surfactants (TWEEN® 80 and Triton™ X-100) to elucidate the relationships between the structural/morphological features of the casting solutions and the physical properties of the resulting thin films. Cryogenic transmission microscopy (cryo-TEM), static/dynamic light scattering (SLS/DLS), and small-angle X-ray scattering (SAXS) revealed contrasting colloidal dispersion states and phase behavior among the three casting solutions. Casting solution with the Triton™ X-100 surfactant produced stable (>90 days) nanoparticles with good dispersion in solution (mean particle size ∼10 nm) as well as good mesopore volume (characterized by nitrogen physisorption) in powder and thin films of high mechanical strength (characterized by the nanoindentation test). The longer main chain and bulkier side units of the TWEEN® 80 surfactant led to stable micelle-nanoparticle coexisting dispersion, which resulted in the highest mesopore volume in powder and thin films with the lowest dielectric constant (∼3) among the samples in this study. The casting solution without the surfactant failed to produce a stabilized solution or thin films of acceptable uniformity. These findings demonstrate the possibility of fine-tuning low-k silica film properties by controlling the colloidal state of casting solutions. PMID:27401818

  8. Structure and properties of polypropylene cast films: Polymer type and processing effects

    NASA Astrophysics Data System (ADS)

    Mileva, Daniela; Gahleitner, Markus; Gloger, Dietrich

    2016-05-01

    The influence of processing parameters in a cast film extrusion process of thin films of isotactic polypropylene homopolymer and random propylene-ethylene copolymer was analyzed. Variation of the chill roll temperature allowed changing the supercooling of the melt and thus the generation of different crystal polymorphs of iPP. Additional focus was placed on the effect of flow induced crystallization via changing the output rate of the line. The crystal structure and morphology of the materials were evaluated and correlated to selected optical and mechanical properties.

  9. Exceptionally crystalline and conducting acid doped polyaniline films by level surface assisted solution casting approach

    NASA Astrophysics Data System (ADS)

    Puthirath, Anand B.; Methattel Raman, Shijeesh; Varma, Sreekanth J.; Jayalekshmi, S.

    2016-04-01

    Emeraldine salt form of polyaniline (PANI) was synthesized by chemical oxidative polymerisation method using ammonium persulfate as oxidant. Resultant emeraldine salt form of PANI was dedoped using ammonia solution and then re-doped with camphor sulphonic acid (CSA), naphthaline sulphonic acid (NSA), hydrochloric acid (HCl), and m-cresol. Thin films of these doped PANI samples were deposited on glass substrates using solution casting method with m-cresol as solvent. A level surface was employed to get homogeneous thin films of uniform thickness. Detailed X-ray diffraction studies have shown that the films are exceptionally crystalline. The crystalline peaks observed in the XRD spectra can be indexed to simple monoclinic structure. FTIR and Raman spectroscopy studies provide convincing explanation for the exceptional crystallinity observed in these polymer films. FESEM and AFM images give better details of surface morphology of doped PANI films. The DC electrical conductivity of the samples was measured using four point probe technique. It is seen that the samples also exhibit quite high DC electrical conductivity, about 287 S/cm for CSA doped PANI, 67 S/cm for NSA doped PANI 65 S/cm for HCl doped PANI, and just below 1 S/cm for m-cresol doped PANI. Effect of using the level surface for solution casting is studied and correlated with the observed crystallinity.

  10. Fabrication of TiO2/PU Superhydrophobic Film by Nanoparticle Assisted Cast Micromolding Process.

    PubMed

    Li, Jie; Zheng, Jianyong; Zhang, Jing; Feng, Jie

    2016-06-01

    Lotus-like surfaces have attracted great attentions in recent years for their wide applications in water repellency, anti-fog and self-cleaning. This paper introduced a novel process, nanoparticle assisted cast micromolding, to create polymer film with superhydrophobic surface. Briefly, waterborne polyurethane (WPU) sol and nano TiO2/WPU sol were each cast onto the featured surfaces of the poly(dimethylsiloxane) (PDMS) stamps replicated from fresh lotus leaves. After being dried and peeled off from the stamps, PU and TiO2/WPU replica films were created respectively. To the former, only high hydrophobic property was observed with static water contact angle (WCA) at 142.5 degrees. While to the later, superhydrophobic property was obtained with WCA more than 150 degrees and slide angle less than 3 degrees. Scanning electron microscopy (SEM) imaging showed that the PU replica film only had the micro-papillas and the TiO2/PU replica film not only had micro papillas but also had a large number of nano structures distributed on and between the micro-papillas. Such nano and micro hierarchical structures were very similar with those on the natural lotus leaf surface, thus was the main reason for causing superhydrophobic property. Although an elastic PDMS stamp from lotus leaf was used in herein process, hard molds may also be used in theory. This study supplied an alternative technique for large scale production of polymeric films with superhydrophobic. PMID:27427647

  11. Polymerization of spin-casted epoxy films induced by electron beam or UV irradiation

    NASA Astrophysics Data System (ADS)

    Fujita, I.; Tanaka, Y.; Takezaki, J.

    Polymerization of spin-casted epoxy oligomer resin-films was initiated by electron beam (EB) or UV irradiation and the conversion to polymer was studied as a function of the thickness of the film. The film thickness was varied from 1 to 25 μm. In the EB-irradiation, the number of oligomer molecules reacted per 100 eV of energy absorption ( G-value) increased with increasing thickness up to 10 μm but did not change above this value. In the UV-irradiation, the G-value increased linearly with increasing film thickness. The result was explained by the difference in the penetrating power of the two radiations. The G-values and the quantum yields of the polymerization in the EB- and the UV-irradiations were compared on the basis of the same energy absorbed in the systems; it was found that the EB-irradiation was more effective than the UV-irradiation. Some anomalous polymerization behaviors were observed in thin, spin-casted films.

  12. 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.

  13. 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

  14. Miniaturized pattern formation in elastic films cast on sinusoidally patterned substrates.

    PubMed

    Annepu, Hemalatha; Sarkar, Jayati

    2014-10-21

    The various morphologies that are formed when van der Waals forces or electric field is induced between film cast on a sinusoidal substrate and in contact proximity with a contactor or electrode are studied. Remarkably smaller length scales are achieved (λc < 2.96h) than those obtained with films cast on flat substrates. With van der Waals interactions, the patterns are uniformly formed throughout the film but are not regularly ordered. When electric field is used at critical voltage, more ordered, localized patterns are formed at the zones of large local interaction strengths. When these patterns are evolved by increasing the applied voltage, coexistence of all three phases-cavities, stripes, and columns-is observed throughout the film. The localized patterns that are initially formed vary with the voltage applied and strongly dictate the phases of evolution. A patterned substrate/patterned contactor assembly can be made to operate like its unpatterned counterpart by making the interaction strength same everywhere and yet yield uniform, regularly ordered, highly miniaturized patterns. Such patterns are very useful in various applications like microfluidics; they are formed with great ease and can be morphologically tuned by tuning the externally applied electric field. PMID:25238212

  15. Preparation and characterization of solution cast films of PET, reorganized PET and their MWNT nanocomposites

    NASA Astrophysics Data System (ADS)

    Singh, Arvind R.; Deshpande, Vineeta D.

    2013-06-01

    The samples of polyethylene terephthalate (PET), reorganized PET (r-PET) and their nanocomposites with 0.05 wt % and 0.1 wt % multi walled carbon nanotubes (MWNT) were prepared by standard solution casting method using trifluoroacetic acid (TFA) as a solvent. Reorganization of PET was obtained by precipitation method using TFA as a solvent and acetone as an antisolvent. Structural and morphological properties of the films were investigated by Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Differential Scanning Calorimetry (DSC) was used to study the thermal properties of the films. Bulk resistivity of the prepared samples was studied using LCR meter. The results show better dispersion of MWNT in r-PET than in PET. Better dispersion is attributed to the morphological changes in r-PET. The films obtained were conductive and transparent even after addition of MWNT signifying their use as a flexible solar substrate.

  16. Crystallographic Textures and Morphologies of Solution Cast Ibuprofen Composite Films at Solid Surfaces

    PubMed Central

    2014-01-01

    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

  17. Spin-Casting Polymer Brush Films for Stimuli-Responsive and Anti-Fouling Surfaces.

    PubMed

    Xu, Binbin; Feng, Chun; Hu, Jianhua; Shi, Ping; Gu, Guangxin; Wang, Lei; Huang, Xiaoyu

    2016-03-01

    Surfaces modified with amphiphilic polymers can dynamically alter their physicochemical properties in response to changes of their environmental conditions; meanwhile, amphiphilic polymer coatings with molecular hydrophilic and hydrophobic patches, which can mitigate biofouling effectively, are being actively explored as advanced coatings for antifouling materials. Herein, a series of well-defined amphiphilic asymmetric polymer brushes containing hetero side chains, hydrophobic polystyrene (PS) and hydrophilic poly(ethylene glycol) (PEG), was employed to prepare uniform thin films by spin-casting. The properties of these films were investigated by water contact angle, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and quartz crystal microbalance (QCM). AFM showed smooth surfaces for all films with the roughness less than 2 nm. The changes in water contact angle and C/O ratio (XPS) evidenced the enrichment of PEG or PS chains at film surface after exposed to selective solvents, indicative of stimuli- responsiveness. The adsorption of proteins on PEG functionalized surface was quantified by QCM and the results verified that amphiphilic polymer brush films bearing PEG chains could lower or eliminate protein-material interactions and resist to protein adsorption. Cell adhesion experiments were performed by using HaCaT cells and it was found that polymer brush films possess good antifouling ability. PMID:26905980

  18. Cast iron-base alloy for cylinder/regenerator housing

    NASA Technical Reports Server (NTRS)

    Witter, Stewart L.; Simmons, Harold E.; Woulds, Michael J.

    1985-01-01

    NASACC-1 is a castable iron-base alloy designed to replace the costly and strategic cobalt-base X-40 alloy used in the automotive Stirling engine cylinder/generator housing. Over 40 alloy compositions were evaluated using investment cast test bars for stress-rupture testing. Also, hydrogen compatibility and oxygen corrosion resistance tests were used to determine the optimal alloy. NASACC-1 alloy was characterized using elevated and room temperature tensile, creep-rupture, low cycle fatigue, heat capacity, specific heat, and thermal expansion testing. Furthermore, phase analysis was performed on samples with several heat treated conditions. The properties are very encouraging. NASACC-1 alloy shows stress-rupture and low cycle fatigue properties equivalent to X-40. The oxidation resistance surpassed the program goal while maintaining acceptable resistance to hydrogen exposure. The welding, brazing, and casting characteristics are excellent. Finally, the cost of NASACC-1 is significantly lower than that of X-40.

  19. The metallography of a nickel base casting alloy.

    PubMed

    Lewis, A J

    1975-10-01

    Three groups of tensile test pieces were produced using a nickel base partial denture casting alloy and employing induction fusion in each case. The first group was produced fro new metal, the second from metal which had been recast four times, and the third from new overheated metal. Samples of alloy were cut from each group, and together with a piece from an original ingot, were mounted, polished, etched, and examined under a metallurgical microscope. PMID:1108851

  20. Method of casting pitch based foam

    DOEpatents

    Klett, James W.

    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.

  1. Fluid casting of particle-based articles

    DOEpatents

    Menchhofer, P.

    1995-03-28

    A method is disclosed 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 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. 1 figure.

  2. Fluid casting of particle-based articles

    DOEpatents

    Menchhofer, Paul

    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.

  3. Casting of particle-based hollow shapes

    DOEpatents

    Menchhofer, P.

    1997-09-09

    A method is disclosed for the production of hollow 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 coated onto a prewarmed continuous surface in a relatively thin layer so that the slurry is substantially uniformly coated on the surface. The heat of the prewarmed surface conducts to the slurry to initiate a reaction which causes the slurry to set or harden in a shape conforming to the surface. The hardened configurations may then be sintered to consolidate the particles and provide a high density product. 9 figs.

  4. Casting of particle-based hollow shapes

    DOEpatents

    Menchhofer, P.

    1995-05-30

    A method is disclosed for the production of hollow 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 coated onto a prewarmed continuous surface in a relatively thin layer so that the slurry is substantially uniformly coated on the surface. The heat of the prewarmed surface conducts to the slurry to initiate a reaction which causes the slurry to set or harden in a shape conforming to the surface. The hardened configurations may then be sintered to consolidate the particles and provide a high density product. 9 figs.

  5. Growth directions of C8-BTBT thin films during drop-casting

    NASA Astrophysics Data System (ADS)

    Iizuka, Naoki; Zanka, Tomohiko; Onishi, Yosuke; Fujieda, Ichiro

    2016-02-01

    Because charge transport in a single crystal is anisotropic, control of its orientation is important for enhancing electrical characteristics and reducing variations among devices. For growing an organic thin film, a solution process such as inkjet printing offers advantages in throughput. We have proposed to apply an external temperature gradient during drop-casting and to control the direction of solvent evaporation. In experiment, a temperature gradient was generated in a bare Si substrate by placing it on a Si plate bridging two heat stages. When a solution containing 2,7-dioctyl [1]benzothieno[3,2-b]benzothiophene (C8-BTBT) was dropped on the substrate, evaporation started at the hotter side of the droplet and proceeded toward the colder side. The front line of the liquid was not pinned and the solution extended toward the colder region. As a result, a thin film was formed in a 7mm-long region. The peripheral region of the film was significantly thicker due to the coffee ring effect. The surface of the rest of the film was mostly smooth and terrace structures with 2.6nm steps were observed. The step roughly corresponds to the length of the C8-BTBT molecule. The film thickness varied from 20nm to 50nm over the distance of 3mm. Another film was grown on a glass substrate under a similar condition. Observation of the film with a polarizing microscope revealed that fan-shaped domains were formed in the film and that their optical axes were mostly along the directions of the solvent evaporation.

  6. Improving Drug Loading of Mucosal Solvent Cast Films Using a Combination of Hydrophilic Polymers with Amoxicillin and Paracetamol as Model Drugs

    PubMed Central

    Kianfar, Farnoosh

    2013-01-01

    Solvent cast mucosal films with improved drug loading have been developed by combining carboxymethyl cellulose (CMC), sodium alginate (SA), and carrageenan (CAR) using paracetamol and amoxicillin as model drugs and glycerol (GLY) as plasticizer. Films were characterized using X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), folding resilience, swelling capacity, mucoadhesivity, and drug dissolution studies. SA, CMC, and GLY (5 : 3 : 6) films showed maximum amoxicillin loading of 26.3% whilst CAR, CMC, and GLY (1 : 2 : 3) films had a maximum paracetamol loading of 40%. XRPD analysis showed different physical forms of the drugs depending on the amount loaded. Films containing 29.4% paracetamol and 26.3% amoxicillin showed molecular dispersion of the drugs while excess paracetamol was observed on the film surface when the maximum 40% was loaded. Work of adhesion was similar for blank films with slightly higher cohesiveness for CAR and CMC based films, but the differences were significant between paracetamol and amoxicillin containing films. The stickiness and cohesiveness for drug loaded films were generally similar with no significant differences. The maximum percentage cumulative drug release was 84.65% and 70.59% for paracetamol and amoxicillin, respectively, with anomalous case two transport mechanism involving both drug diffusion and polymer erosion. PMID:23841056

  7. 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.

  8. A novel dimethylformamide (DMF) free bar-cast method to deposit organolead perovskite thin films with improved stability.

    PubMed

    Jones, Eurig W; Holliman, Peter J; Connell, Arthur; Davies, Matthew L; Baker, Jennifer; Hobbs, Robert J; Ghosh, Sanjay; Furnell, Leo; Anthony, Rosie; Pleydell-Pearce, Cameron

    2016-03-10

    We report a solvent-free approach to synthesizing organolead perovskites by using solid state reactions to coat perovskite crystals onto Al2O3 or TiO2 nanoparticles followed by addition of terpineol affording perovskite inks. We have bar cast these inks to produce photoactive perovskite thin films which are significantly more stable to humidity than solution-processed films. This new method also avoids the use of toxic DMF solvent. PMID:26962574

  9. Modelling of liquid metal flow and oxide film defects in filling of aluminium alloy castings

    NASA Astrophysics Data System (ADS)

    Dai, X.; Jolly, M.; Yang, X.; Campbell, J.

    2012-07-01

    The liquid metal flow behaviours in different runner system designs have important effects on the mechanical strength of aluminium alloy castings. In this paper, a new model has been developed which is a two-dimensional program using a finite difference technique and the Marker and Cell (MAC) method to simulate the flow of liquid metal during filling a mould. In the program the Eulerian method has been used for the liquid metal flow, while the Oxide Film Entrainment Tracking Algorithm (OFET) method (a Lagrangian method) has been used to simulate the movement of the oxide film on the liquid metal surface or in the liquid metal flow. Several examples have been simulated and tested and the relevant results were obtained. These results were compared with measured bending strengths. It was found that the completed program was capable of simulating effectively the filling processes of different runner systems. The simulation results are consistent with the experiment. In addition, the program is capable of providing clearer images for predicting the distribution of the oxide film defects generated during filling a mould.

  10. 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

  11. Comparative study on properties of edible films based on pinhao (Araucaria angustifolia) starch and flour

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The aim of this study was to develop and compare the properties of edible films based on pinhao starch and pinhao flour. Seven formulations were developed by casting methodology: 5% pinhao starch with 0, 1, 1.5, and 2% glycerol, and 5% pinhao flour with 1, 1.5, and 2% glycerol. The films were evalua...

  12. Fabrication of superhydrophobic and heat-insulating antimony doped tin oxide/polyurethane films by cast replica micromolding.

    PubMed

    Feng, Jie; Huang, Baoyuan; Zhong, Mingqiang

    2009-08-01

    A novel process for fabricating superhydrophobic and heat-insulating polymeric nanocomposite films was developed. Briefly, antimony doped tin oxide (ATO) nanoparticles that commonly endow coats heat-insulating and transparent functions were mixed into commercial waterborne polyurethane (WPU) suspensions to obtain ATO/WPU suspensions, which were then cast onto poly(dimethylsiloxane) (PDMS) stamps replicated from fresh lotus leaves. After being dried and peeled off from stamps, ATO/PU films with superhydrophobic surface and heat-insulating property were created, while PU films without ATO only showed high hydrophobicity. Scanning electron microscopy (SEM) imaging showed the surface of ATO/PU superhydrophobic films had unique micro- and nano-structures similar with those on the lotus leaf. On the contrary, no obvious nano-structures were found on the surface of pure PU films, demonstrating mixing functional nanoparticles into polymers is a necessary and feasible step in creating superhydrophobic and functional films by replica molding method. PMID:19394955

  13. Effectiveness of silane monomer and gamma radiation on chitosan films and PCL-based composites

    NASA Astrophysics Data System (ADS)

    Sharmin, Nusrat; Khan, Ruhul A.; Dussault, Dominic; Salmieri, Stephane; Akter, Nousin; Lacroix, Monique

    2012-08-01

    Chitosan films were prepared by casting from its 1% (w/w) solution. Tensile strength (TS) and tensile modulus (TM) of chitosan films were found to be 30 MPa and 450 MPa, respectively. Silane monomer (3-aminopropyl tri-methoxysilane) (0.25%, w/w) was added into the chitosan solution (1%, w/w) and films were casted. Then films were exposed to gamma radiation (5-25 kGy) and mechanical properties were investigated. It was found that at 10 kGy, the values of TS and TM were improved significantly. Silane grafted chitosan film reinforced poly(caprolactone) (PCL)-based tri-layer composites were prepared by compression molding. Silane improved interfacial adhesion between chitosan and PCL in composites. Surface of the films was investigated by scanning electron microscope (SEM) and found better morphology for silane grafted films.

  14. Vertical water distribution during the drying of polymer films cast from aqueous emulsions

    NASA Astrophysics Data System (ADS)

    Gorce, J.-P.; Bovey, D.; McDonald, P. J.; Palasz, P.; Taylor, D.; Keddie, J. L.

    2002-07-01

    We present a systematic study of the vertical uniformity of water distribution during the drying of waterborne colloidal films, testing the predictions of a Peclet number Pe defined for this system. Pe indicates the relative contributions of water evaporation and Brownian diffusion in determining the concentration profile in the vertical direction (i.e. normal to the substrate). When textit{Pe} < 1, the water concentration in films cast from an alkyd emulsion is found via magnetic-resonance profiling to be uniform with depth, which is consistent with expectations. When textit{Pe} > 1, a gradient in the water concentration develops, with less water near the interface with air. The water profiles reveal that the alkyd particles do not coalesce immediately upon contact in close-packing. At later times, a concentrated surface layer develops, but particles are not coalesced in this layer to form a continuous “skin”, but rather the structure is likely to be that of a biliquid foam.

  15. Real-time measurement system for tracking birefringence, weight, thickness, and surface temperature during drying of solution cast coatings and films

    NASA Astrophysics Data System (ADS)

    Unsal, E.; Drum, J.; Yucel, O.; Nugay, I. I.; Yalcin, B.; Cakmak, M.

    2012-02-01

    This paper describes the design and performance of a new instrument to track temporal changes in physical parameters during the drying behavior of solutions, as well as curing of monomers. This real-time instrument follows in-plane and out-of-plane birefringence, weight, thickness, and surface temperature during the course of solidification of coatings and films through solvent evaporation and thermal or photocuring in a controlled atmosphere. It is specifically designed to simulate behavior of polymer solutions inside an industrial size, continuous roll-to-roll solution casting line and other coating operations where resins are subjected to ultraviolet (UV) curing from monomer precursors. Controlled processing parameters include air speed, temperature, initial cast thickness, and solute concentration, while measured parameters are thickness, weight, film temperature, in-plane and out-of-plane birefringence. In this paper, we illustrate the utility of this instrument with solution cast and dried poly (amide-imide)/DMAc (Dimethylacetamide) solution, water based black paint, and organo-modified clay/NMP (N-Methylpyrrolidone) solution. In addition, the physical changes that take place during UV photo polymerization of a monomer are tracked. This instrument is designed to be generic and it can be used for tracking any drying/swelling/solidification systems including paper, foodstuffs such as; grains, milk as well as pharmaceutical thin paste and slurries.

  16. On the stabilizing effects of neck-in, gravity, and inertia in Newtonian film casting

    NASA Astrophysics Data System (ADS)

    Bechert, M.; Schubert, D. W.; Scheid, B.

    2016-02-01

    We investigate the influence of the reduction of width along the stretching direction, the so-called neck-in effect, on the draw resonance instability in Newtonian film casting using a linear stability analysis of a model of reduced dimensionality including gravity and inertia forces. Proper scaling reveals the aspect ratio, i.e., the ratio of the initial film half-width to the film length, together with the fluidity and the inlet velocity as independent, dimensionless control parameters. Moreover, we introduce the local Trouton ratio as a measure for the type of elongational deformation, which can be uniaxial, planar, or a combination of both. In the case of purely uniaxial or planar deformations, a one-dimensional model is sufficient. The influence of the control parameters on the draw resonance instability, including a threshold to unconditional stability, is visualized by several stability maps. Special cases of viscous-gravity and viscous-inertia models are analyzed separately due to their practical importance. Gravity appears to influence the aspect ratio at which the critical draw ratio is maximum and amplifies the stabilizing effect of the neck-in. Inertia increases the stabilization due to neck-in, eventually leading to a window of unconditional stability within the analyzed region of aspect ratios. The mechanism underlying the complete suppression of draw resonance is presented, using exclusively steady state analysis. Additionally, the stabilizing mechanisms of gravity and neck-in are revealed. Known alternative stability criteria are extended to the case of finite width and their validity is tested in the presence of inertia, gravity, and finite aspect ratios.

  17. 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.

  18. Direct Isosurface Ray Casting of NURBS-Based Isogeometric Analysis.

    PubMed

    Schollmeyer, Andre; Froehlich, Bernd

    2014-09-01

    In NURBS-based isogeometric analysis, the basis functions of a 3D model's geometric description also form the basis for the solution space of variational formulations of partial differential equations. In order to visualize the results of a NURBS-based isogeometric analysis, we developed a novel GPU-based multi-pass isosurface visualization technique which performs directly on an equivalent rational Bézier representation without the need for discretization or approximation. Our approach utilizes rasterization to generate a list of intervals along the ray that each potentially contain boundary or isosurface intersections. Depth-sorting this list for each ray allows us to proceed in front-to-back order and enables early ray termination. We detect multiple intersections of a ray with the higher-order surface of the model using a sampling-based root-isolation method. The model's surfaces and the isosurfaces always appear smooth, independent of the zoom level due to our pixel-precise processing scheme. Our adaptive sampling strategy minimizes costs for point evaluations and intersection computations. The implementation shows that the proposed approach interactively visualizes volume meshes containing hundreds of thousands of Bézier elements on current graphics hardware. A comparison to a GPU-based ray casting implementation using spatial data structures indicates that our approach generally performs significantly faster while being more accurate. PMID:26357373

  19. Functional chitosan-based grapefruit seed extract composite films for applications in food packaging technology

    SciTech Connect

    Tan, Y.M.; Lim, S.H.; Tay, B.Y.; Lee, M.W.; Thian, E.S.

    2015-09-15

    Highlights: • Chitosan-based grapefruit seed extract (GFSE) films were solution casted. • GFSE was uniformly dispersed within all chitosan film matrices. • All chitosan-based composite films showed remarkable transparency. • Increasing amounts of GFSE incorporated increased the elongation at break of films. • Chitosan-based GFSE composite films inhibited the proliferation of fungal growth. - Abstract: Chitosan-based composite films with different amounts of grapefruit seed extract (GFSE) (0.5, 1.0 and 1.5% v/v) were fabricated via solution casting technique. Experimental results showed that GFSE was uniformly dispersed within all chitosan film matrices. The presence of GFSE made the films more amorphous and tensile strength decreased, while elongation at break values increased as GFSE content increased. Results from the measurement of light transmission revealed that increasing amounts of GFSE (from 0.5 to 1.5% v/v) did not affect transparency of the films. Furthermore, packaging of bread samples with chitosan-based GFSE composite films inhibited the proliferation of fungal growth as compared to control samples. Hence, chitosan-based GFSE composite films have the potential to be a useful material in the area of food technology.

  20. 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. PMID:25917333

  1. The metallography of heat treatment effects in a nickel-base casting alloy. A preliminary report.

    PubMed

    Goodall, T G; Lewis, A J

    1979-08-01

    A series of standard tensile specimens produced from a nickel-base removable partial denture casting alloy were subjected to heat treatments at three temperatures and three periods at each temperature. The microstructures developed within the castings disclose changes in both the matrix and interdendritic zones. PMID:296698

  2. A method for surface quality assessment of die-castings based on laser triangulation

    NASA Astrophysics Data System (ADS)

    Bračun, Drago; Gruden, Valter; Možina, Janez

    2008-04-01

    This paper presents a new method for the surface quality assessment of safety-critical die-castings. We have developed a measurement system that measures the surface of a die-casting and provides quantitative surface quality assessment within a die-casting cycle of 70 s. The measurement system, based on the laser triangulation principle, has an asymmetrical measuring range and is capable of high-resolution measurements of the casting surface (0.02 mm). Geometry specific parameters (flatness of the particular surface region, average deviation of the measured points and height of the surface defects) are calculated from the acquired surface data and then checked whether/how they fit within the tolerances specified in a technical documentation. The method has been tested in the laboratory by examination of a sample of castings taken randomly from the production process. A comparison of the results obtained by this method and by a qualified operator has shown good agreement.

  3. Influence of solvent polarity on the structure of drop-cast electroactive tetra(aniline)-surfactant thin films.

    PubMed

    Dane, Thomas G; Bartenstein, Julia E; Sironi, Beatrice; Mills, Benjamin M; Alexander Bell, O; Emyr Macdonald, J; Arnold, Thomas; Faul, Charl F J; Briscoe, Wuge H

    2016-09-21

    The influence of processing conditions on the thin film microstructure is a fundamental question that must be understood to improve the performance of solution-processed organic electronic materials. Using grazing-incidence X-ray diffraction, we have studied the structure of thin films of a tetra(aniline)-surfactant complex prepared by drop-casting from five solvents (hexane, chloroform, tetrahydrofuran, dichloromethane and ethanol), selected to cover a range of polarities. We found that the structure, level of order and degree of orientation relative to the substrate were extremely sensitive to the solvent used. We have attempted to correlate such solvent sensitivity with a variety of solvent physical parameters. Of particular significance is the observation of a sharp structural transition in the thin films cast from more polar solvents; such films presented significantly greater crystallinity as measured by the coherence length and paracrystalline disorder parameter. We attribute this higher structural order to enhanced dissociation of the acid surfactant in the more polar solvents, which in turn promotes complex formation. Furthermore, the more polar solvents provide more effective screening of (i) the attractive ionic interaction between oppositely charged molecules, providing greater opportunity for dynamic reorganisation of the supramolecular aggregates into more perfect structures; and (ii) the repulsive interaction between the positively charged blocks permitting a solvophobic-driven aggregation of the aromatic surfaces during solvent evaporation. PMID:27539382

  4. A simple, safe and affordable cast-based guided implant placement system.

    PubMed

    Stumpel, Lambert J

    2015-03-01

    A fully restrictive surgical guide allows controlled execution of a preoperatively planned osteotomy and subsequent implant placement. There are two fabrication modes. One is a digital path, where these guides can be fabricated based on data from a cone beam CT source. Alternatively, 3-D data can be derived from a dental cast and periapical radiographs. The 3D Click Guide is a cast-based, fully restrictive surgical guide that can be generated in the dental office. PMID:25864302

  5. Fiber laser cladding of nickel-based alloy on cast iron

    NASA Astrophysics Data System (ADS)

    Arias-González, F.; del Val, J.; Comesaña, R.; Penide, J.; Lusquiños, F.; Quintero, F.; Riveiro, A.; Boutinguiza, M.; Pou, J.

    2016-06-01

    Gray cast iron is a ferrous alloy characterized by a carbon-rich phase in form of lamellar graphite in an iron matrix while ductile cast iron presents a carbon-rich phase in form of spheroidal graphite. Graphite presents a higher laser beam absorption than iron matrix and its morphology has also a strong influence on thermal conductivity of the material. The laser cladding process of cast iron is complicated by its heterogeneous microstructure which generates non-homogeneous thermal fields. In this research work, a comparison between different types of cast iron substrates (with different graphite morphology) has been carried out to analyze its impact on the process results. A fiber laser was used to generate a NiCrBSi coating over flat substrates of gray cast iron (EN-GJL-250) and nodular cast iron (EN-GJS-400-15). The relationship between processing parameters (laser irradiance and scanning speed) and geometry of a single laser track was examined. Moreover, microstructure and composition were studied by Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and X-Ray Diffraction (XRD). The hardness and elastic modulus were analyzed by means of micro- and nanoindentation. A hardfacing coating was generated by fiber laser cladding. Suitable processing parameters to generate the Ni-based alloy coating were determined. For the same processing parameters, gray cast iron samples present higher dilution than cast iron samples. The elastic modulus is similar for the coating and the substrate, while the Ni-based coating obtained presents a significantly superior hardness than cast iron.

  6. Ultrasonic Substrate Vibration-Assisted Drop Casting (SVADC) for the Fabrication of Photovoltaic Solar Cell Arrays and Thin-Film Devices

    NASA Astrophysics Data System (ADS)

    Eslamian, Morteza; Zabihi, Fatemeh

    2015-12-01

    A simple, low-cost, versatile, and potentially scalable casting method is proposed for the fabrication of micro- and nano-thin films, herein termed as ultrasonic "substrate vibration-assisted drop casting" (SVADC). The impingement of a solution drop onto a substrate in a simple process called drop casting, usually results in spreading of the liquid solution and the formation of a non-uniform thin solid film after solvent evaporation. Our previous and current supporting results, as well as few similar reports by others, confirm that imposing ultrasonic vibration on the substrate can simply convert the uncontrollable drop casting method into a controllable coating technique. Therefore, the SVADC may be used to fabricate an array of emerging thin-film solar cells, such as polymer, perovskite, and quantum-dot solar cells, as well as other small thin-film devices, in a roll-to-roll and automated fabrication process. The preliminary results demonstrate a ten-fold increase in electrical conductivity of PEDOT: PSS made by SVADC compared with the film made by conventional drop casting. Also, simple planar perovskite solar cells made here using SVADC show promising performance with an efficiency of over 3 % for a simple structure without performing process optimization or using expensive materials and treatments.

  7. Caste-, work-, and descent-based discrimination as a determinant of health in social epidemiology.

    PubMed

    Patil, Rajan R

    2014-01-01

    Social epidemiology explores health in the context of broad social determinants of health, where the boundary lines between health and politics appear increasingly blurred. Social determinants of health such as caste, discrimination, and social exclusion are inherently political in nature, hence it becomes imperative to look at health through a broader perspective of political philosophy, ideology, and caste that imposes enormous obstacles to a person's full attainment of civil, political, economic, social, and cultural rights. Caste is descent based and hereditary in nature. It is a characteristic determined by one's birth into a particular caste, irrespective of the faith practiced by the individual. Caste denotes a system of rigid social stratification into ranked groups defined by descent and occupation. Under various caste systems throughout the world, caste divisions also dominate in housing, marriage, and general social interaction divisions that are reinforced through the practice and threat of social ostracism, economic boycotts, and even physical violence-all of which undermine health equality. PMID:24871772

  8. Antimicrobial and physical-mechanical properties of agar-based films incorporated with grapefruit seed extract.

    PubMed

    Kanmani, Paulraj; Rhim, Jong-Whan

    2014-02-15

    The use of synthetic petroleum based packaging films caused serious environmental problems due to their difficulty in recycling and poor biodegradability. Therefore, present study was aimed to develop natural biopolymer-based antimicrobial packaging films as an alternative for the synthetic packaging films. As a natural antimicrobial agent, grapefruit seed extract (GSE) has been incorporated into agar to prepare antimicrobial packaging film. The films with different concentrations of GSE were prepared by a solvent casting method and the resulting composite films were examined physically and mechanically. In addition, the films were characterized by FE-SEM, XRD, FT-IR and TGA. The incorporation of GSE caused increase in color, UV barrier, moisture content, water solubility and water vapor permeability, while decrease in surface hydrophobicity, tensile strength and elastic modulus of the films. As the concentration of GSE increased from 0.6 to 13.3 μg/mL, the physical and mechanical properties of the films were affected significantly. The addition of GSE changed film microstructure of the film, but did not influence the crystallinity of agar and thermal stability of the agar-based films. The agar/GSE films exhibited distinctive antimicrobial activity against three test food pathogens, such as Listeria monocytogenes, Bacillus cereus and Escherichia coli. These results suggest that agar/GSE films have potential to be used in an active food packaging systems for maintaining food safety and extending the shelf-life of the packaged food. PMID:24507339

  9. Electrical and Mechanical Properties of the Dielectric Capacitor Film Based on Polyvinylidene Fluoride and Aromatic Polythiourea

    NASA Astrophysics Data System (ADS)

    Li, Ya; Fu, Qiong; Li, Lili; Li, Weiping

    2016-06-01

    To obtain the flexible dielectric material suitable for mass produced supercapacitor, blend films based on polyvinylidene fluoride (PVDF) and aromatic polythiourea (ArPTU) were prepared by solution casting. We found that the PVDF/ArPTU blend film is a good energy storage material for capacitors with high breakdown strength and low loss at high filed. The breakdown field of PVDF/ArPTU (90/10) film is more than 700 MV/m, and the maximum released energy density is up to 11 J/cm3 with discharging efficiency above 80%. We also proved that the mechanical property of blend films is much better than that of pure ArPTU film, and the toughness and softness are close to the level of PVDF film. The blend film based on PVDF and ArPTU is a flexible dielectric material in the manufacture of supercapacitor.

  10. Urinary casts

    MedlinePlus

    ... Casts in the urine; Fatty casts; Red blood cell casts; White blood cell casts ... The absence of cellular casts or presence of a few hyaline casts is normal. The examples above are common measurements for results of ...

  11. Urinary casts

    MedlinePlus

    ... people with advanced kidney disease and chronic kidney failure . White blood cell (WBC) casts are more common ... Hyaline casts; Granular casts; Renal tubular epithelial casts; Waxy casts; Casts in the ...

  12. Study on the solidification condition of exudation penetration occurrence in grey cast iron castings based on solidification simulation

    NASA Astrophysics Data System (ADS)

    Han, Jianmin; Hansen, S. F.

    2000-11-01

    The solidification condition of eutectic exudation penetration occurrence, a kind of casting defect in grey cast-iron castings, is studied with computer solidification simulation and experiments on specially designed castings. A hot hole refers to the solidification condition when the temperature gradient or solidifying time gradient from the centre to the surface at some location in a casting is positive during the solidification process. It is a term proposed in this paper to better describe the condition of exudation penetration occurrence and for predicting its location at hot spots in a casting. The term is useful for improving the foundry technology used for solving the penetration problem with the help of computer simulation.

  13. Physicochemical and Microstructural Characterization of Corn Starch Edible Films Obtained by a Combination of Extrusion Technology and Casting Technique.

    PubMed

    Fitch-Vargas, Perla Rosa; Aguilar-Palazuelos, Ernesto; de Jesús Zazueta-Morales, José; Vega-García, Misael Odín; Valdez-Morales, Jesús Enrique; Martínez-Bustos, Fernando; Jacobo-Valenzuela, Noelia

    2016-09-01

    Starch edible films (EFs) have been widely studied due to their potential in food preservation; however, their application is limited because of their poor mechanical and barrier properties. Because of that, the aim of this work was to use the extrusion technology (Ex T) as a pretreatment of casting technique to change the starch structure in order to obtain EFs with improved physicochemical properties. To this, corn starch and a mixture of plasticizers (sorbitol and glycerol, in different ratios) were processed in a twin screw extruder to generate the starch modification and subsequently casting technique was used for EFs formation. The best conditions of the Ex T and plasticizers concentration were obtained using response surface methodology. All the response variables evaluated, were affected significatively by the Plasticizers Ratio (Sorbitol:Glycerol) (PR (S:G)) and Extrusion Temperature (ET), while the Screw Speed (SS) did not show significant effect on any of these variables. The optimization study showed that the appropriate conditions to obtain EFs with the best mechanical and barrier properties were ET = 89 °C, SS = 66 rpm and PR (S:G) = 79.7:20.3. Once the best conditions were obtained, the optimal treatment was characterized according to its microstructural properties (X-ray diffraction, Scanning Electron Microscopy and Atomic Force Microscopy) to determine the damage caused in the starch during Ex T and casting technique. In conclusion, with the combination of Ex T and casting technique were obtained EFs with greater breaking strength and deformation, as well as lower water vapor permeability than those reported in the literature. PMID:27550869

  14. Facile preparation and thermoelectric properties of Bi₂Te₃ based alloy nanosheet/PEDOT:PSS composite films.

    PubMed

    Du, Yong; Cai, K F; Chen, Song; Cizek, Pavel; Lin, Tong

    2014-04-23

    Bi2Te3 based alloy nanosheet (NS)/poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) composite films were prepared separately by spin coating and drop casting techniques. The drop cast composite film containing 4.10 wt % Bi2Te3 based alloy NSs showed electrical conductivity as high as 1295.21 S/cm, which is higher than that (753.8 S/cm) of a dimethyl sulfoxide doped PEDOT:PSS film prepared under the same condition and that (850-1250 S/cm) of the Bi2Te3 based alloy bulk material. The composite film also showed a very high power factor value, ∼32.26 μWm(-1) K(-2). With the content of Bi2Te3 based alloy NSs increasing from 0 to 4.10 wt %, the electrical conductivity and Seebeck coefficient of the composite films increase simultaneously. PMID:24666341

  15. Si-nanocrystal/P3HT hybrid films with a 50- and 12-fold enhancement of hole mobility and density: films prepared by successive drop casting.

    PubMed

    Kajiya, Daisuke; Saitow, Ken-ichi

    2015-10-14

    Hybrid silicon nanocrystal (Si-NC)/poly(3-hexylthiophene) (P3HT) films serve as the active layers of quantum dot/polymer hybrid photovoltaics. To achieve effective photovoltaic properties, it is necessary to enhance the charge carrier mobility and carrier density of the P3HT films. A 50- and 12-fold enhancement of the hole mobility and hole density, respectively, was achieved along the out-of-plane direction of a Si-NC/P3HT hybrid film, which corresponds to the carrier-migration direction between the photovoltaic electrodes. According to time-of-flight, electronic absorption, Raman, atomic force microscopy, photoluminescence lifetime, and X-ray diffraction measurements, the significant enhancement of the mobility and density was attributed to both an increase in the P3HT crystallinity and the dissociation efficiency of P3HT excitons on the addition of Si-NCs to the P3HT films. These enhancements were achieved using a film preparation method developed in the present study, which has been named successive drop casting. PMID:26355280

  16. 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

  17. 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

  18. 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 ...

  19. Casting Technology.

    ERIC Educational Resources Information Center

    Wright, Michael D.; And Others

    1992-01-01

    Three articles discuss (1) casting technology as it relates to industry, with comparisons of shell casting, shell molding, and die casting; (2) evaporative pattern casting for metals; and (3) high technological casting with silicone rubber. (JOW)

  20. Fabrication and Electrical Characteristics of Graphite/Carbon Nanotube/Polyvinyl Butyral Composite Film via Tape-Casting and Heat-Treatment.

    PubMed

    Kim, Min-Young; Choi, Seung-Woo; Boo, Seong Jae; Lee, Jong-Ho; Noh, Hee Sook; Kim, Ho-Sung

    2015-10-01

    Composite stacking films, which can be applied as the bipolar plates of redox flow batteries, were fabricated via a tape-casting process that used slurry of graphite, CNT, and resin materials. The slurry was made of 25~45 wt% conductive filler (graphite, CNT) and 55~75 wt% polyvinyl butyral (PVB) binder solution (binder, dispersant, plasticizer, and solvent). The sheet thickness of the composite films was controlled to 70~150 μm, and composite films of about 1 mm in thickness were also fabricated by stacking and laminating the sheet film, including the conductive filler of above 85 wt%. The effects of the shape and physical properties of the graphite were investigated with regard to the dispersion behavior and flow of the slurry on the carrier film of the tape-casting device. As a result, the acicular graphite showed a good dispersion property with the resin of the PVB binder, as compared to spherical graphite. The composite film with acicular graphite showed a lower resistivity than that of a film with spherical graphite. Furthermore, the effects of adding a small amount of CNT and the heat-treatment to the composite stacking film were also studied. Finally, the composite film showed an electrical characteristic of below 50 mΩ·cm and a high bending strength of above 20 MPa. PMID:26726462

  1. The Effects of Confinement of Thin Spin Cast Films of Perfluorinated Ionomers

    NASA Astrophysics Data System (ADS)

    Perahia, Dvora; Hill, Teresa

    2003-03-01

    The surface structure and its response to annealing upon confinement of spin coated perfluorinated ion-containing polymer have been studied by atomic force microscopy, X-ray scattering, and non-polarized neutron reflectometry. Similar to self- assembled films, the spin coated ionomers form structured films consisting of bundles of micelles. In contrast to self-assembled films, in spin coated ones hexagonal arrangements of the basic structural units are observed. Films with thickness ranging from 350 Å to 1050 Å have been investigated as a function of annealing time above the glass transition temperature of the fluorinated backbones. The films remain intact and do not de-wet when heated above the glass transition temperature of the polymer, contrary to what has been observed in thin di-block copolymers. The film thickness affects the ability of the ionomer to rearrange and releases constraints imposed by the spin coating procedure.

  2. Sophorolipid-induced dimpling and increased porosity in solvent-cast short-chain polyhydroxyalkanoate films: impact on thermo-mechanical properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sophorolipids (SL; microbial glycolipids) were used as additives in solvent-cast short-chain polyhydroxyalkanoate (sc-PHA) films to enhance surface roughness and porosity. Poly-3-hydroxybutyrate (PHB), poly-(6%)-3-hydroxybutyrate-co-(94%)-3-hydroxyvalerate (PHB/V), and poly-(90%)-3-hydroxybutyrate-c...

  3. Welding and mechanical properties of cast FAPY (Fe-16 at. % Al-based) alloy slabs

    SciTech Connect

    Sikka, V.K.; Goodwin, G.M.; Alexander, D.J.; Howell, C.R.

    1995-08-01

    The low-aluminum-content iron-aluminum program deals with the development of a Fe-Al alloy with aluminum content such as a produce the minimum environmental effect at room temperature. The FAPY is an Fe-16 at. % Al-based alloy developed at the Oak Ridge National Laboratory as the highest aluminum-containing alloy with essentially no environmental effect. The chemical composition for FAPY in weight percent is: aluminum = 8.46, chromium = 5.50, zirconium = 0.20, carbon = 0.03, molybdenum = 2.00, yttrium = 0.10, and iron = 83.71. The cast ingots of the alloy can be hot worked by extrusion, forging, and rolling processes. The hot- worked cast structure can be cold worked with intermediate anneals at 800{degrees}C. Typical room-temperature ductility of the fine-grained wrought structure is 20 to 25% for this alloy. In contrast to the wrought structure, the cast ductility at room temperature is approximately 1% with a transition temperature of approximately 100 to 150{degrees}C, above which ductility values exceed 20%. The alloy has been melted and processed into bar, sheet, and foil. The alloy has also been cast into slabs, step-blocks of varying thicknesses, and shapes. The purpose of this section is to describe the welding response of cast slabs of three different thicknesses of FAPY alloy. Tensile, creep, and Charpy-impact data of the welded plates are also presented.

  4. Effect of casting geometry on mechanical properties of two nickel-base superalloys

    NASA Technical Reports Server (NTRS)

    Johnston, J. R.; Dreshfield, R. L.; Collins, H. E.

    1976-01-01

    An investigation was performed to determine mechanical properties of two rhenium-free modifications of alloy TRW, and to evaluate the suitability of the alloy for use in a small integrally cast turbine rotor. The two alloys were initially developed using stress rupture properties of specimens machined from solid gas turbine blades. Properties in this investigation were determined from cast to size bars and bars cut from 3.8 by 7.6 by 17.8 cm blocks. Specimens machined from blocks had inferior tensile strength and always had markedly poorer rupture lives than cast to size bars. At 1,000 C the cast to size bars had shorter rupture lives than those machined from blades. Alloy R generally had better properties than alloy S in the conditions evaluated. The results show the importance of casting geometry on mechanical properties of nickel base superalloys and suggest that the geometry of a component can be simulated when developing alloys for that component.

  5. An Informatics Based Approach to Reduce the Grain Size of Cast Hadfield Steel

    NASA Astrophysics Data System (ADS)

    Dey, Swati; Pathak, Shankha; Sheoran, Sumit; Kela, Damodar H.; Datta, Shubhabrata

    2016-04-01

    Materials Informatics concept using computational intelligence based approaches are employed to bring out the significant alloying additions to achieve grain refinement in cast Hadfield steel. Castings of Hadfield steels used for railway crossings, requires fine grained austenitic structure. Maintaining proper grain size of this component is very crucial in order to achieve the desired properties and service life. This work studies the important variables affecting the grain size of such steels which includes the compositional and processing variables. The computational findings and prior knowledge is used to design the alloy, which is subjected to a few trials to validate the findings.

  6. The effect of aluminium on the metallography of a nickel base removable partial denture casting alloy.

    PubMed

    Lewis, A J

    1978-12-01

    Three special nickel-chromium alloys were prepared in which the aluminum levels were adjusted both above and below that of a commercial nickel base dental casting alloy. Tensile and metallographic evaluation of representative samples of the alloys were made and the changes in the properties of the alloys are reported. PMID:285671

  7. 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

  8. Covalent cum noncovalent functionalizations of carbon nanotubes for effective reinforcement of a solution cast composite film.

    PubMed

    Yuan, Wei; Chan-Park, Mary B

    2012-04-01

    Although carbon nanotubes have impressive tensile properties, exploiting these properties in composites, especially those made by the common solution casting technique, seems to be elusive thus far. The reasons could be partly due to the poor nanotube dispersion and the weak nanotube/matrix interface. To solve this dual pronged problem, we combine noncovalent and covalent functionalizations of nanotubes in a single system by the design and application of a novel dispersant, hydroxyl polyimide-graft-bisphenol A diglyceryl acrylate (PI(OH)-BDA), and use them with epoxidized single-walled carbon nanotubes (O-SWNTs). Our novel PI(OH)-BDA dispersant functionalizes the nanotubes noncovalently to achieve good dispersion of the nanotubes because of the strong π-π interaction due to main chain and steric hindrance of the BDA side chain. PI(OH)-BDA also functionalizes O-SWNTs covalently because it reacts with epoxide groups on the nanotubes, as well as the cyanate ester (CE) matrix used. The resulting solution-cast CE composites show 57%, 71%, and 124% increases in Young's modulus, tensile strength, and toughness over neat CE. These values are higher than those of composites reinforced with pristine SWNTs, epoxidized SWNTs, and pristine SWNTs dispersed with PI(OH)-BDA. The modulus and strength increase per unit nanotube weight fraction, i.e., dE/dW(NT) and dσ/dW(NT), are 175 GPa and 7220 MPa, respectively, which are significantly higher than those of other nanotube/thermosetting composites (22-70 GPa and 140-3540 MPa, respectively). Our study indicates that covalent cum noncovalent functionalization of nanotubes is an effective tool for improving both the nanotube dispersion and nanotube/matrix interfacial interaction, resulting in significantly improved mechanical reinforcement of the solution-cast composites. PMID:22432973

  9. Investment casting of {gamma}-TiAl-based alloys: Microstructure and data base for gas turbine applications

    SciTech Connect

    Wagner, R.; Appel, F.; Dogan, B.

    1995-12-31

    Investment casting is regarded as an economic processing technology for the production of {gamma}-TiAl based components for gas turbine applications. Near net-shape parts can be cast such that they are free from pores and flaws after adequate `HIP`ping. The inhomogeneous cast microstructure which results from locally varying cooling rates (e.g. in the root and foil of a blade), however, is often retained even after heat-treatments necessary to achieve a balance of properties for a given application. Appropriate modifications of the alloy chemistry may lead to an improved microstructural homogeneity in the cast parts. Data bases of properties (tensile properties, creep, fatigue and rupture strength, fracture and impact toughness, oxidation and corrosion resistance) which are relevant for potential gas turbine applications have been assessed for different cast {gamma}-TiAl alloys with different microstructures. These are compared with corresponding properties of nickel-based and iron-based superalloys {gamma}-TiAl is competing with for substitution.

  10. Influence of high doses γ-irradiation on oxygen permeability of linear low-density polyethylene and cast polypropylene films

    NASA Astrophysics Data System (ADS)

    Klepac, Damir; Ščetar, Mario; Baranović, Goran; Galić, Kata; Valić, Srećko

    2014-04-01

    Linear low density polyethylene (PE-LLD) and cast polypropylene (PPcast) films were irradiated in a 60Co γ-source. The total irradiation dose varied from 0 kGy (unirradiated samples) to 200 kGy. Oxygen transport was investigated by a manometric method and the structural changes were studied by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR). Free radicals decay as a function of time was monitored by electron spin resonance (ESR) spectroscopy. The results show that the γ-irradiation reduces oxygen permeability coefficient in both films. The reduction was associated with an increase in crystallinity. DSC thermograms revealed a decrease in PPcast melting point with increasing irradiation dose, indicating higher degradation compared to PE-LLD. The observed peak in FTIR spectra for both samples at 1716 cm-1 corresponds to the stretching of the carbonyl and carboxylic groups which arise from the reaction of oxygen with the free radicals produced in the polymer matrix as a result of irradiation.

  11. Nanocomposite films based on xylan-rich hemicelluloses and cellulose nanofibers with enhanced mechanical properties.

    PubMed

    Peng, Xin-wen; Ren, Jun-li; Zhong, Lin-xin; Sun, Run-cang

    2011-09-12

    Interest in xylan-rich hemicelluloses (XH) film is growing, and efforts have been made to prepare XH films with improved mechanical properties. This work described an effective approach to produce nanocomposite films with enhanced mechanical properties by incorporation of cellulose nanofibers (CNFs) into XH. Aqueous dispersions of XH (64-75 wt %), sorbitol (16-25 wt %), and CNF (0-20 wt %) were cast at a temperature of 23 °C and 50% relative humidity. The surface morphology of the films was revealed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The thermal properties and crystal structure of the films were evaluated by thermal analysis (TG) and X-ray diffraction (XRD). The surface of XH films with and without CNF was composed primarily of nanonodules, and CNFs were embedded in the XH matrix. Freeze-dried XH powder was amorphous, whereas the films with and without CNF showed a distinct peak at around 2θ = 18°, which suggested that XH molecules aggregated or reordered in the casting solution or during water evaporation. Furthermore, the nanocomposite films had improved thermal stability. XH film with 25 wt % plasticizer (sorbitol, based on dry XH weight) showed poor mechanical properties, whereas incorporation of CNF (5-20 wt %, based on the total dry mixture) into the film resulted in enhanced mechanical properties due to the high aspect ratio and mechanical strength of CNF and strong interactions between CNF and XH matrix. This effective method makes it possible to produce hemicellulose-based biomaterials of high quality. PMID:21815695

  12. Composite edible films based on hydroxypropyl methylcellulose reinforced with microcrystalline cellulose nanoparticles.

    PubMed

    Bilbao-Sáinz, Cristina; Avena-Bustillos, Roberto J; Wood, Delilah F; Williams, Tina G; McHugh, Tara H

    2010-03-24

    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 this work was to enhance these properties by reinforcing the films with microcrystalline cellulose (MCC) at the nano scale level. Three sizes of MCC nanoparticles were incorporated into HPMC edible films at different concentrations. Identical MCC nanoparticles were lipid coated (LC) prior to casting into HPMC/LC-MCC composite films. The films were examined for mechanical and moisture barrier properties verifying how the addition of cellulose nanoparticles affected the water affinities (water adsorption/desorption isotherms) and the diffusion coefficients. The expected reinforcing effect of the MCC was observed: HPMC/MCC and HPMC/LC-MCC films showed up to 53% and 48% increase, respectively, in tensile strength values in comparison with unfilled HPMC films. Furthermore, addition of unmodified MCC nanoparticles reduced the moisture permeability up to 40% and use of LC-MCC reduced this value up to 50%. Water vapor permeability was mainly influenced by the differences in water solubility of different composite films since, in spite of the increase in water diffusivity values with the incorporation of MCC to HPMC films, better moisture barrier properties were achieved for HPMC/MCC and HPMC/LC-MCC composite films than for HPMC films. PMID:20187652

  13. 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

  14. [Design of a volume-rendering toolkit using GPU-based ray-casting].

    PubMed

    Liu, Wen-Qing; Chen, Chun-Xiao; Lu, Li-Na

    2009-09-01

    This paper presents an approach to GPU-based ray-casting of a shader model 3.0 compatible graphics card. In addition, a software toolkit is designed using the proposed algorithm to make the full benefit of GPU by extending VTK. Experimental results suggest that remarkable speedups are observed using GPU-based algorithm, and high-quality renderings can be achieved at interactive framerates above 60 fps. The toolkit designed provides a high level of usability and extendibility. PMID:20073244

  15. 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

  16. Research of image enhancement of dental cast based on wavelet transformation

    NASA Astrophysics Data System (ADS)

    Zhao, Jing; Li, Zhongke; Liu, Xingmiao

    2010-10-01

    This paper describes a 3D laser scanner for dental cast that realize non-contact deepness measuring. The scanner and the control PC make up of a 3D scan system, accomplish the real time digital of dental cast. Owing to the complexity shape of the dental cast and the random nature of scanned points, the detected feature curves are generally not smooth or not accurate enough for subsequent application. The purpose of this p is to present an algorithm for enhancing the useful points and eliminating the noises. So an image enhancement algorithm based on wavelet transform and fuzzy set theory is presented. Firstly, the multi-scale wavelet transform is adopted to decompose the input image, which extracts the characteristic of multi-scale of the image. Secondly, wavelet threshold is used for image de-noising, and then the traditional fuzzy set theory is improved and applied to enhance the low frequency wavelet coefficients and the high frequency wavelet coefficients of different directions of each scale. Finally, the inverse wavelet transform is applied to synthesis image. A group of experimental results demonstrate that the proposed algorithm is effective for the dental cast image de-noising and enhancement, the edge of the enhanced image is distinct which is good for the subsequent image processing.

  17. 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.

  18. 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

  19. Preparation and properties of films cast from mixtures of poly(vinyl alcohol) and submicron particles prepared from amylose-palmitic acid inclusion complexes.

    PubMed

    Fanta, George F; Selling, Gordon W; Felker, Frederick C; Kenar, James A

    2015-05-01

    The use of starch in polymer composites for film production has been studied for increasing biodegradability, improving film properties and reducing cost. In this study, submicron particles were prepared from amylose-sodium palmitate complexes both by rapidly cooling jet-cooked starch-palmitic acid mixtures and by acidifying solutions of starch-sodium palmitate complexes. Films were cast containing poly(vinyl alcohol) (PVOH) with up to 50% starch particles. Tensile strength decreased and Young's modulus increased with starch concentration, but percent elongations remained similar to controls regardless of preparation method or starch content. Microscopy showed particulate starch distribution in films made with rapidly cooled starch-palmitic acid particles but smooth, diffuse starch staining with acidified sodium palmitate complexes. The mild effects on tensile properties suggest that submicron starch particles prepared from amylose-palmitic acid complexes provide a useful, commercially viable approach for PVOH film modification. PMID:25659717

  20. 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.

  1. Novel composite films based on amidated pectin for cationic dye adsorption.

    PubMed

    Nesic, Aleksandra R; Velickovic, Sava J; Antonovic, Dusan G

    2014-04-01

    Pectin, with its tendency to gel in the presence of metal ions has become a widely used material for capturing the metal ions from wastewaters. Its dye-capturing properties have been much less investigated, and this paper is the first to show how films based on amidated pectin can be used for cationic dye adsorption. In the present study amidated pectin/montmorillonite composite films were synthesized by membrane casting, and they are stable in aqueous solution both below and above pectin pKa. FTIR, thermogravimetry and SEM-EDAX have confirmed the presence of montmorillonite in the cast films and the interactions between the two constituents. In order to evaluate the cationic dye adsorption of these films Basic Yellow 28 was used, showing that the films have higher adsorption capacity compared to the others reported in the literature. The results were fitted into Langmuir, Freundlich and Temkin isotherms indicating an exothermic process and setting the optimum amount of montmorillonite in the films to 30% of pectin mass. According to the Langmuir isotherm the maximum adsorption capacity is 571.4 mg/g. PMID:24268651

  2. 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…

  3. Cobalt-Based Hard Magnets, Thin Films and Multilayers

    NASA Astrophysics Data System (ADS)

    Gao, Chuan

    1991-02-01

    Co-based magnetic materials including bulk, thin film and magnetic multilayers have been studied. The purpose of the first part of this work is to study a Co -based transition metal alloy to be processed to result in significant enhancement of its magnetic properties (coercivity, magnetization, and energy product) in the absence rare earths. CoZr(Hf)BSi alloys have been studied. Rapidly quenched Co_ {78}Zr_{16}B_3Si_3 and Co_{76}Hf_ {76}B_3Si_3 showed the highest coercivity (6.7 kOe and 6.5 kOe respectively). This is the highest room temperature coercivity reported in a non -rare-earth containing magnet up to now. This system has excellent thermal stability. Co-based thin film alloys were also studied and we obtain coercivities as high as 700 Oe for sputtered thin films. This lies in between the maximum value obtained for as-cast bulk alloys (50 Oe) and rapidly quenched alloys (6.7 kOe). Multilayers were studied with the objective of determining the effect of interfaces on the magnetic properties of Co alloys. Multilayers of the form Co/Cu, Co_{95}B _5/Cu and Co/Al were studied and the interface anisotropy was found to favor a magnetization perpendicular to the film. Very thin magnetic layers led to very small coercivities since the size of magnetic domains was restricted. We also noted some interesting layer-layer magnetic interactions. Finally some unusual magnetization reversal behavior was noted in which the magnetic moment goes to zero and reverses before the applied field goes to zero.

  4. 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

  5. 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.

  6. An intelligent knowledge based approach for the automated radiographic inspection of castings

    NASA Astrophysics Data System (ADS)

    Kehoe, A.; Parker, G. A.

    An automated system for the radiographic inspection of castings is described which is based on both conventional image processing techniques and intelligent knowledge based techniques for the identification and evaluation of defects against quality assurance standards. An evaluation of the performance of the system against that of skilled inspectors demonstrates that the system is capable of meeting the requirements for an automated system for industrial radiographic inspection. The overall design of the system and elements of the system, including the knowledge representation scheme, inference mechanism, and control structure, are described. The discussion also covers examples of frame structures, frame taxonomies, data driven maintenance procedures, and rules for classification and evaluation.

  7. Evaluation of electroslag castings

    SciTech Connect

    Judkins, R.R.; Sikka, V.K.

    1985-01-01

    Results of evaluations of electroslag castings of ferritic (2-1/4 Cr-1 Mo and 9 Cr-1 Mo) and austenitic (CF8M or type 316) steels are presented. The castings have been characterized for surface finish, cracking, solidification structure, chemical composition, hardness, ferrite distribution, tensile properties, Charpy impact properties, and creep properties. Pertinent data are compared with equivalent data for sand castings and wrought products of the same materials. Based on the results of these studies, the properties of electroslag castings compare favorably with those of sand castings and wrought materials.

  8. 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

  9. 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

  10. Drug release profiles and microstructural characterization of cast and freeze dried vitamin B12 buccal films by positron annihilation lifetime spectroscopy.

    PubMed

    Szabó, Barnabás; Kállai, Nikolett; Tóth, Gergő; Hetényi, Gergely; Zelkó, Romána

    2014-02-01

    Solvent cast and freeze dried films, containing the water-soluble vitamin B12 as model drug were prepared from two polymers, sodium alginate (SA), and Carbopol 71G (CP). The proportion of the CP was changed in the films. The microstructural characterization of various samples was carried out by positron annihilation lifetime spectroscopy (PALS). The drug release kinetics of untreated and stored samples was evaluated by the conventionally applied semi-empirical power law. Correlation was found between the changes of the characteristic parameters of the drug release and the ortho-positronium (o-Ps) lifetime values of polymer samples. The results indicated that the increase of CP concentration, the freeze-drying process and the storage at 75% R.H. decreased the rate of drug release. The PALS method enabled the distinction between the micro- and macrostructural factors influencing the drug release profile of polymer films. PMID:24269613

  11. Moving cast shadow resistant for foreground segmentation based on shadow properties analysis

    NASA Astrophysics Data System (ADS)

    Zhou, Hao; Gao, Yun; Yuan, Guowu; Ji, Rongbin

    2015-12-01

    Moving object detection is the fundamental task in machine vision applications. However, moving cast shadows detection is one of the major concerns for accurate video segmentation. Since detected moving object areas are often contain shadow points, errors in measurements, localization, segmentation, classification and tracking may arise from this. A novel shadow elimination algorithm is proposed in this paper. A set of suspected moving object area are detected by the adaptive Gaussian approach. A model is established based on shadow optical properties analysis. And shadow regions are discriminated from the set of moving pixels by using the properties of brightness, chromaticity and texture in sequence.

  12. 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 μm. 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.

  13. Plane-based sampling for ray casting algorithm in sequential medical images.

    PubMed

    Lin, Lili; Chen, Shengyong; Shao, Yan; Gu, Zichun

    2013-01-01

    This paper proposes a plane-based sampling method to improve the traditional Ray Casting Algorithm (RCA) for the fast reconstruction of a three-dimensional biomedical model from sequential images. In the novel method, the optical properties of all sampling points depend on the intersection points when a ray travels through an equidistant parallel plan cluster of the volume dataset. The results show that the method improves the rendering speed at over three times compared with the conventional algorithm and the image quality is well guaranteed. PMID:23424608

  14. Bio-based barium alginate film: Preparation, flame retardancy and thermal degradation behavior.

    PubMed

    Liu, Yun; Zhang, Chuan-Jie; Zhao, Jin-Chao; Guo, Yi; Zhu, Ping; Wang, De-Yi

    2016-03-30

    A bio-based barium alginate film was prepared via a facile ionic exchange and casting approach. Its flammability, thermal degradation and pyrolysis behaviors, thermal degradation mechanism were studied systemically by limiting oxygen index (LOI), vertical burning (UL-94), microscale combustion calorimetry (MCC), thermogravimetric analysis (TGA) coupled with Fourier transform infrared analysis (FTIR) and pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS). It showed that barium alginate film had much higher LOI value (52.0%) than that of sodium alginate film (24.5%). Moreover, barium alginate film passed the UL-94 V-0 rating, while the sodium alginate film showed no classification. Importantly, peak of heat release rate (PHRR) of barium alginate film in MCC test was much lower than that of sodium alginate film, suggested that introduction of barium ion into alginate film significantly decreased release of combustible gases. TG-FTIR and Py-GC-MS results indicated that barium alginate produced much less flammable products than that of sodium alginate in whole thermal degradation procedure. Finally, a possible degradation mechanism of barium alginate had been proposed. PMID:26794953

  15. 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.

  16. 49 CFR 173.183 - Nitrocellulose base film.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Nitrocellulose base film. 173.183 Section 173.183... Nitrocellulose base film. Films, nitrocellulose base, must be packaged in packagings conforming to the... tape or paper; authorized only for not over 600 m (1969 feet) of film....

  17. 49 CFR 173.183 - Nitrocellulose base film.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Nitrocellulose base film. 173.183 Section 173.183... Nitrocellulose base film. Films, nitrocellulose base, must be packaged in packagings conforming to the... tape or paper; authorized only for not over 600 m (1969 feet) of film....

  18. 49 CFR 173.183 - Nitrocellulose base film.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Nitrocellulose base film. 173.183 Section 173.183... Nitrocellulose base film. Films, nitrocellulose base, must be packaged in packagings conforming to the... tape or paper; authorized only for not over 600 m (1969 feet) of film....

  19. Thin film based plasmon nanorulers

    NASA Astrophysics Data System (ADS)

    Taylor, Alexander D.; Lu, Chang; Geyer, Scott; Carroll, D. L.

    2016-07-01

    In this work, isolated metal nanoparticles are supported on a dielectric thin film that is placed on a conducting plane. The optical scattering characteristics of these metal nanoparticles are directly correlated with the localized surface plasmon states of the nanoparticle—image particle dimer, formed in the conducting plane below. Quantification of plasmon resonance shifts can be directly correlated with the application of the plasmon nanoruler equation. This simple geometry shows that direct optical techniques can be used to resolve thickness variations in dielectrics of only a few nanometers.

  20. Classification techniques based on AI application to defect classification in cast aluminum

    NASA Astrophysics Data System (ADS)

    Platero, Carlos; Fernandez, Carlos; Campoy, Pascual; Aracil, Rafael

    1994-11-01

    This paper describes the Artificial Intelligent techniques applied to the interpretation process of images from cast aluminum surface presenting different defects. The whole process includes on-line defect detection, feature extraction and defect classification. These topics are discussed in depth through the paper. Data preprocessing process, as well as segmentation and feature extraction are described. At this point, algorithms employed along with used descriptors are shown. Syntactic filter has been developed to modelate the information and to generate the input vector to the classification system. Classification of defects is achieved by means of rule-based systems, fuzzy models and neural nets. Different classification subsystems perform together for the resolution of a pattern recognition problem (hybrid systems). Firstly, syntactic methods are used to obtain the filter that reduces the dimension of the input vector to the classification process. Rule-based classification is achieved associating a grammar to each defect type; the knowledge-base will be formed by the information derived from the syntactic filter along with the inferred rules. The fuzzy classification sub-system uses production rules with fuzzy antecedent and their consequents are ownership rates to every defect type. Different architectures of neural nets have been implemented with different results, as shown along the paper. In the higher classification level, the information given by the heterogeneous systems as well as the history of the process is supplied to an Expert System in order to drive the casting process.

  1. Grain refinement of permanent mold cast copper base alloys. Final report

    SciTech Connect

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

    2004-04-29

    Grain refinement behavior of copper alloys cast in permanent molds was investigated. This is one of the least studied subjects in copper alloy castings. Grain refinement is not widely practiced for leaded copper alloys cast in sand molds. Aluminum bronzes and high strength yellow brasses, cast in sand and permanent molds, were usually fine grained due to the presence of more than 2% iron. Grain refinement of the most common permanent mold casting alloys, leaded yellow brass and its lead-free replacement EnviroBrass III, is not universally accepted due to the perceived problem of hard spots in finished castings and for the same reason these alloys contain very low amounts of iron. The yellow brasses and Cu-Si alloys are gaining popularity in North America due to their low lead content and amenability for permanent mold casting. These alloys are prone to hot tearing in permanent mold casting. Grain refinement is one of the solutions for reducing this problem. However, to use this technique it is necessary to understand the mechanism of grain refinement and other issues involved in the process. The following issues were studied during this three year project funded by the US Department of Energy and the copper casting industry: (1) Effect of alloying additions on the grain size of Cu-Zn alloys and their interaction with grain refiners; (2) Effect of two grain refining elements, boron and zirconium, on the grain size of four copper alloys, yellow brass, EnviroBrass II, silicon brass and silicon bronze and the duration of their effect (fading); (3) Prediction of grain refinement using cooling curve analysis and use of this method as an on-line quality control tool; (4) Hard spot formation in yellow brass and EnviroBrass due to grain refinement; (5) Corrosion resistance of the grain refined alloys; (6) Transfer the technology to permanent mold casting foundries; It was found that alloying elements such as tin and zinc do not change the grain size of Cu-Zn alloys

  2. Surface analysis of cast aluminum by means of artificial vision and AI-based techniques

    NASA Astrophysics Data System (ADS)

    Platero, Carlos; Fernandez, Carlos; Campoy, Pascual; Aracil, Rafael

    1996-02-01

    An architecture for surface analysis of continuous cast aluminum strip is described. The data volume to be processed has forced up the development of a high-parallel architecture for high- speed image processing. An especially suitable lighting system has been developed for defect enhancing in metallic surfaces. A special effort has been put in the design of the defect detection algorithm to reach two main objectives: robustness and low processing time. These goals have been achieved combining a local analysis together with data interpretation based on syntactical analysis that has allowed us to avoid morphological analysis. Defect classification is accomplished by means of rule-based systems along with data-based classifiers. The use of clustering techniques is discussed to perform partitions in Rn by SOM, divergency methods to reduce the feature vector applied to the data-based classifiers. The combination of techniques inside a hybrid system leads to near 100% classification success.

  3. Enhanced Performance Consistency in Nanoparticle/TIPS Pentacene-Based Organic Thin Film Transistors

    SciTech Connect

    He, Zhengran; Xiao, Kai; Durant, William Mark; Anthony, John E.; Kilbey, II, S Michael; Chen, Jihua; Li, Dawen

    2011-01-01

    In this study, inorganic silica nanoparticles are used to manipulate the morphology of 6,13-bis(triisopropylsilylethynyl)-pentacene (TIPS pentacene) thin films and the performance of solution-processed organic thin-film transistors (OTFTs). This approach is taken to control crystal anisotropy, which is the origin of poor consistency in TIPS pentacene based OTFT devices. Thin film active layers are produced by drop-casting mixtures of SiO{sub 2} nanoparticles and TIPS pentacene. The resultant drop-cast films yield improved morphological uniformity at {approx}10% SiO{sub 2} loading, which also leads to a 3-fold increase in average mobility and nearly 4 times reduction in the ratio of measured mobility standard deviation ({mu}{sub Stdev}) to average mobility ({mu}{sub Avg}). Grazing-incidence X-ray diffraction, scanning and transmission electron microscopy as well as polarized optical microscopy are used to investigate the nanoparticle-mediated TIPS pentacene crystallization. The experimental results suggest that the SiO{sub 2} nanoparticles mostly aggregate at TIPS pentacene grain boundaries, and 10% nanoparticle concentration effectively reduces the undesirable crystal misorientation without considerably compromising TIPS pentacene crystallinity.

  4. Poly(vinyl alcohol)-based film potentially suitable for antimicrobial packaging applications.

    PubMed

    Musetti, Alessandro; Paderni, Katia; Fabbri, Paola; Pulvirenti, Andrea; Al-Moghazy, Marwa; Fava, Patrizia

    2014-04-01

    This work aimed at developing a thin and water-resistant food-grade poly(vinyl alcohol) (PVOH)-based matrix able to swell when in contact with high moisture content food products without rupturing to release antimicrobial agents onto the food surface. This film was prepared by blending PVOH and 7.20% (wt/wt of PVOH) of poly(ethylene glycol) (PEG) with citric acid as crosslinking agent. The film-forming solution was then casted onto a flat surface and the obtained film was 60 μm in thickness and showed a good transparency (close to T = 100%) in the visible region (400 to 700 nm). After immersion in water for 72 h at room temperature, the crosslinked matrix loses only 19.2% of its original weight (the percentage includes the amount of unreacted crosslinking agent, antimicrobial in itself). Water content, degree of swelling, and crosslinking density of the film prove that the presence of PEG diminishes the hydrophilic behavior of the material. Also the mechanical properties of the wet and dry film were assessed. Alongside this, 2.5% (wt/wt of dry film) of grapefruit seed extract (GSE), an antimicrobial agent, was added to the film-forming solution just before casting and the ability of the plastic matrix to release the additive was then evaluated in vitro against 2 GSE-susceptible microorganisms, Salmonella enteritidis and Listeria innocua. The results indicate that the developed matrix may be a promising food-grade material for the incorporation of active substances. PMID:24611868

  5. Preparation of nano cellulose fibers and its application in kappa-carrageenan based film.

    PubMed

    Savadekar, N R; Karande, V S; Vigneshwaran, N; Bharimalla, A K; Mhaske, S T

    2012-12-01

    Bio-based nanocomposite films were successfully developed using nanofibrillated cellulose (NFC) as the reinforcing phase and kappa-carrageenan (KCRG) as the matrix. NFC was successfully synthesis from short stable cotton fibers by chemo-mechanical process. The bionanocomposites were prepared by incorporating 0.1, 0.2, 0.3, 0.4, 0.5, and 1wt% of the NFC into a KCRG matrix using a solution casting method there characterization was done in terms of thermal properties (DSC), morphology (SEM), water vapor transmission rate (WVTR), oxygen transmission rate (OTR), X-ray diffractograms (XRD), and tensile properties. The main conclusion arising from the analysis of the result is that the bionanocomposites containing 0.4wt% of NFC exhibited the highest enhancement in tensile strength it is almost 44% improvement. WVTR and OTR results showed improvement of all nanocomposite film compare to control KCRG film. PMID:22940239

  6. (100)-Textured KNN-based thick film with enhanced piezoelectric property for intravascular ultrasound imaging

    PubMed Central

    Zhu, Benpeng; Zhang, Zhiqiang; Ma, Teng; Yang, Xiaofei; Li, Yongxiang; Shung, K. Kirk; Zhou, Qifa

    2015-01-01

    Using tape-casting technology, 35 μm free-standing (100)-textured Li doped KNN (KNLN) thick film was prepared by employing NaNbO3 (NN) as template. It exhibited similar piezoelectric behavior to lead containing materials: a longitudinal piezoelectric coefficient (d33) of ∼150 pm/V and an electromechanical coupling coefficient (kt) of 0.44. Based on this thick film, a 52 MHz side-looking miniature transducer with a bandwidth of 61.5% at −6 dB was built for Intravascular ultrasound (IVUS) imaging. In comparison with 40 MHz PMN-PT single crystal transducer, the rabbit aorta image had better resolution and higher noise-to-signal ratio, indicating that lead-free (100)-textured KNLN thick film may be suitable for IVUS (>50 MHz) imaging. PMID:25991874

  7. (100)-Textured KNN-based thick film with enhanced piezoelectric property for intravascular ultrasound imaging

    NASA Astrophysics Data System (ADS)

    Zhu, Benpeng; Zhang, Zhiqiang; Ma, Teng; Yang, Xiaofei; Li, Yongxiang; Shung, K. Kirk; Zhou, Qifa

    2015-04-01

    Using tape-casting technology, 35 μm free-standing (100)-textured Li doped KNN (KNLN) thick film was prepared by employing NaNbO3 (NN) as template. It exhibited similar piezoelectric behavior to lead containing materials: a longitudinal piezoelectric coefficient (d33) of ˜150 pm/V and an electromechanical coupling coefficient (kt) of 0.44. Based on this thick film, a 52 MHz side-looking miniature transducer with a bandwidth of 61.5% at -6 dB was built for Intravascular ultrasound (IVUS) imaging. In comparison with 40 MHz PMN-PT single crystal transducer, the rabbit aorta image had better resolution and higher noise-to-signal ratio, indicating that lead-free (100)-textured KNLN thick film may be suitable for IVUS (>50 MHz) imaging.

  8. Development and Characterization of Edible Films Based on Fruit and Vegetable Residues.

    PubMed

    Andrade, Roberta M S; Ferreira, Mariana S L; Gonçalves, Édira C B A

    2016-02-01

    Edible films were developed from the solid residue of the processing of whole fruits and vegetables. The solid residue, processed into flour (FVR flour) was chemically and structurally characterized by microstructure, elemental composition, structural links, and moisture sorption isotherm. Films were prepared by casting using aqueous extracts of 8% and 10% of flour (w/w) and characterized in terms of thickness, water solubility, mechanical properties, water vapor permeability, and Fourier transform infrared (FTIR). The analysis of microstructure and elemental composition, performed on flour (mean particle size 350 μm), showed an essentially granular aspect, with the presence of fibrous particles having potassium as one of the most abundant elements. FTIR results showed similarity between the characteristic bands of other raw materials used in edible films. The sorption isotherm of FVR flour showed a typical profile of foods rich in soluble components, such as sugars. Dried films presented an average thickness of 0.263 ± 0.003 mm, a homogenous aspect, bright yellow color, pronounced fruit flavor, and high water solubility. The FTIR spectra of the edible films revealed that addition of potato skin flour did not change the molecular conformation. Moreover, the films presented low tensile strength at break when compared with fruit starch-based films. PMID:26766297

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

    DOEpatents

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

    1978-03-14

    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 cobalt, tungsten, molybdenum, vanadium, columbium, tantalum, boron, zirconium, carbon and hafnium. The invention grain refines these alloys to ASTM 2 to 4 increasing low cycle fatigue life by a factor of 2 to 5 (i.e. life of 700 hours would be increased to 1400 to 3500 hours for a given stress) as a result of the addition of 0.01% to 0.2% of a member of the group consisting of boron, zirconium and mixtures thereof to aid heterogeneous nucleation. The alloy is vacuum melted and heated to 250.degree.-400.degree. F. above the melting temperature, cooled to partial solidification, thus resulting in said heterogeneous nucleation and fine grains, then reheated and cast at about 50.degree.-100.degree. F. of superheat. Additions of 0.1% boron and 0.1% zirconium (optional) are the preferred nucleating agents.

  10. Thermally induced grinding damage in cast equiaxed nickel-based superalloys

    SciTech Connect

    Kovach, J.A.

    1986-01-01

    The overall objective of this program was to increase the understanding and productivity of conventional grinding operations utilized in the finishing of cast equiaxed nickel-based superalloy components. To achieve this overall goal a four phase approach was employed. Initially, a grinding energy partition relationship for conventional grinding of superalloys was developed. Secondly, the mechanisms and conditions that influence superalloy microcracking during abusive grinding were determined. Third, building on the above relationships, a means of readily predicting the onset of grinding damage in cast Rene-77 and B-1900 superalloys was established. Finally, the results were implemented in production surface grinding operations to increase superalloy grinding quality and productivity. Finite element analyses were utilized to determine the superalloy grinding zone temperatures and residual stresses. The results indicated that Rene-77 microcracks are not formed by the residual stresses alone. The effects of constitutional liquation or weakening of the grain boundaries due to rapid heating to such temperatures were shown to be significant. It was then demonstrated that workplace damage would occur when the combined conducted and convected heat flux exceeded a critical limit.

  11. In vitro comparative survey of cell adhesion and proliferation of human induced pluripotent stem cells on surfaces of polymeric electrospun nanofibrous and solution-cast film scaffolds.

    PubMed

    Hoveizi, Elham; Ebrahimi-Barough, Somayeh; Tavakol, Shima; Nabiuni, Mohammad

    2015-09-01

    Extracellular matrix (ECM) components play a critical role in regulating cell behaviors. Interactions between ECM components and cells are important in various biological processes, including cell attachment, survival, morphogenesis, spreading, proliferation, and gene expression. In this study the in vitro responses of human induced pluripotent stem cells (hiPSCs) on polycaprolactone (PCL) electrospun nanofibrous scaffold were reported in comparison with those of the cells on corresponding solution-cast film scaffold. Our results demonstrated that the nanofibrous scaffold showed better support for the attachment and proliferation of hiPSCs than their corresponding film scaffold. Consequently, we emphasize that hiPSCs can sense the physical properties and chemical composition of the materials and regulate their behaviors accordingly. PMID:25691375

  12. 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.

  13. 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.

  14. Thermal cooling effects in the microstructure and properties of cast cobalt-base biomedical alloys

    NASA Astrophysics Data System (ADS)

    Vega Valer, Vladimir

    Joint replacement prosthesis is widely used in the biomedical field to provide a solution for dysfunctional human body joints. The demand for orthopedic knee and hip implants motivate scientists and manufacturers to develop novel materials or to increase the life of service and efficiency of current materials. Cobalt-base alloys have been investigated by various researchers for biomedical implantations. When these alloys contain Chromium, Molybdenum, and Carbon, they exhibit good tribological and mechanical properties, as well as excellent biocompatibility and corrosion resistance. In this study, the microstructure of cast Co-Cr-Mo-C alloy is purposely modified by inducing rapid solidification through fusion welding processes and solution annealing heat treatment (quenched in water at room temperature. In particular the effect of high cooling rates on the athermal phase transformation FCC(gamma)↔HCP(epsilon) on the alloy hardness and corrosion resistance is investigated. The Co-alloy microstructures were characterized using metallography and microscopy techniques. It was found that the as cast sample typically dendritic with dendritic grain sizes of approximately 150 microm and containing Cr-rich coarse carbide precipitates along the interdendritic boundaries. Solution annealing gives rise to a refined microstructure with grain size of 30 microm, common among Co-Cr-Mo alloys after heat treating. Alternatively, an ultrafine grain structure (between 2 and 10 microm) was developed in the fusion zone for specimens melted using Laser and TIG welding methods. When laser surface modification treatments were implemented, the developed solidification microstructure shifted from dendritic to a fine cellular morphology, with possible nanoscale carbide precipitates along the cellular boundaries. In turn, the solidified regions exhibited high hardness values (461.5HV), which exceeds by almost 110 points from the alloy in the as-cast condition. The amount of developed athermal

  15. [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

  16. Kaolin-based particle films for arthropod control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Particle film technology was conceived by ARS scientists in the mid-1990's as an alternative to chemical pesticides. This technology was based on coating plant parts with mineral films that were chemically inert, could be formulated to spread and create a uniform film, formed a porous film that doe...

  17. 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.

  18. Solvothermal synthesis of Cu2Zn1-x Fe x SnS4 nanoparticles and the influence of annealing conditions on drop-casted thin films

    NASA Astrophysics Data System (ADS)

    Shadrokh, Zohreh; Yazdani, Ahmad; Eshghi, Hosein

    2016-04-01

    Cu2Zn1-x Fe x SnS4 (CZFTS) semiconductor alloy sphere-like nanoparticles were synthesized by a solvothermal method and their thin films were fabricated using a facile drop casting route then annealed in Ar and/or sulfur atmosphere. The sphere-like CZFTS nanoparticles demonstrate promising morphological, structural, and optical properties for an absorber layer in thin film solar cells. X-ray diffraction patterns, Raman spectra and EDS measurements of the samples indicate that a phase transition from kesterite to stannite occurred by increasing the Fe content to Fe/Fe + Zn = 0.61 ratio. Moreover, the increase in Fe content (0 ≤ x ≤ 1) resulted in a variation of the band gap energies of CZFTS from ˜1.515 to 1.206 eV on the basis of a parabolic decreasing trend. From a band gap bowing model we derived a small bowing constant of b ˜ 0.2009 ± 0.02 eV, indicating suitable miscibility of alloyed constituents in the host crystal lattice. The films annealed in sulfur showed a dense, uniform, low-crack surface, high thickness and low transmission compared to the films annealed in Ar flow. The four-point probe analysis showed an increasing resistivity of samples annealed in Ar with increasing Fe content.

  19. Effect of the microhardness difference between base metal and bionic coupling unit on wear resistance of gray cast iron

    NASA Astrophysics Data System (ADS)

    Pang, Zuobo; Zhou, Hong; Chang, Fang; Zhang, Peng; Cong, Dalong; Meng, Chao; Wang, Chuanwei; Ren, Luquan

    2015-12-01

    In order to improve the wear resistance of gray cast iron guide rail, the samples with different microhardness difference between bionic coupling units and base metal were manufactured by laser surface remelting. Wear behavior of gray cast iron with bionic coupling units has been studied under dry sliding condition at room temperature using a homemade liner reciprocating wear testing machine. The wear resistance was evaluated by means of weight loss measurement and wear morphology. The results indicated that when the microhardness difference is 561 HV0.2, the wear resistance of sample is the best.

  20. Displaying structural property and inheritance of cast iron surfacing on steel base

    NASA Astrophysics Data System (ADS)

    Shveev, I. A.

    2016-06-01

    Graphite inclusions heredity in deposited layer from remelted special cast iron billets was established. The possibility of controlling the structural state and the quality of the deposited layer due to technological parameters of welding and heat treatment of parts is shown. Ways of improving cast iron wear resistance durability are proposed.

  1. Thermodynamics-Based Selection and Design of Creep-Resistant Cast Mg Alloys

    NASA Astrophysics Data System (ADS)

    Abaspour, Saeideh; Cáceres, Carlos H.

    2015-12-01

    Atomic level thermodynamics arguments that account for the generally weak age hardening response while suggesting that extending the athermal regime through short-range order (SRO) is a most feasible path to increasing the creep strength of many current alloys are presented. The tendency, or otherwise, of many solutes to develop SRO in dilute solid solutions rationalizes a number of observations in current multicomponent Mg alloys, and in particular the retention of linear strain hardening at high temperatures, while it disputes the viability of several micromechanisms often considered active, such as pinning of edge dislocations by mobile solute clouds, dynamic precipitation of thermally stable precipitates, or atomic size effects on the diffusivity. Potential solutes are sorted out and ranked based on the sign and value of the enthalpy of mixing of binary solid solutions using the Miedema phenomenological scheme. Due to their large negative energy of mixing and reasonable solubility (>1 at. pct) at ~473 K (~200 °C), Y and Gd appear as the best candidates to increase the creep strength through SRO, followed by Nd and Ca, in close agreement with data reported in the literature. The feasibility of enhancing the age hardening response through homogeneously nucleated, coherent precipitates, in some cases despite the negative energy of mixing of the alloy, or via internally ordered precipitates mimicking those present in Mg-Th alloys is considered by making parallels with the Al-Zn and the Al-Cu alloy systems. The possible optimization of the strengthening of high pressure die cast alloys combining SRO and intergranular eutectics or of heat-treatable cast alloys through internally ordered precipitates and SRO is discussed.

  2. A general and Robust Ray-Casting-Based Algorithm for Triangulating Surfaces at the Nanoscale

    PubMed Central

    Decherchi, Sergio; Rocchia, Walter

    2013-01-01

    We present a general, robust, and efficient ray-casting-based approach to triangulating complex manifold surfaces arising in the nano-bioscience field. This feature is inserted in a more extended framework that: i) builds the molecular surface of nanometric systems according to several existing definitions, ii) can import external meshes, iii) performs accurate surface area estimation, iv) performs volume estimation, cavity detection, and conditional volume filling, and v) can color the points of a grid according to their locations with respect to the given surface. We implemented our methods in the publicly available NanoShaper software suite (www.electrostaticszone.eu). Robustness is achieved using the CGAL library and an ad hoc ray-casting technique. Our approach can deal with any manifold surface (including nonmolecular ones). Those explicitly treated here are the Connolly-Richards (SES), the Skin, and the Gaussian surfaces. Test results indicate that it is robust to rotation, scale, and atom displacement. This last aspect is evidenced by cavity detection of the highly symmetric structure of fullerene, which fails when attempted by MSMS and has problems in EDTSurf. In terms of timings, NanoShaper builds the Skin surface three times faster than the single threaded version in Lindow et al. on a 100,000 atoms protein and triangulates it at least ten times more rapidly than the Kruithof algorithm. NanoShaper was integrated with the DelPhi Poisson-Boltzmann equation solver. Its SES grid coloring outperformed the DelPhi counterpart. To test the viability of our method on large systems, we chose one of the biggest molecular structures in the Protein Data Bank, namely the 1VSZ entry, which corresponds to the human adenovirus (180,000 atoms after Hydrogen addition). We were able to triangulate the corresponding SES and Skin surfaces (6.2 and 7.0 million triangles, respectively, at a scale of 2 grids per Å) on a middle-range workstation. PMID:23577073

  3. A new generation of electrochemical supercapacitors based on layer-by-layer polymer films

    NASA Astrophysics Data System (ADS)

    Christinelli, Wania Ap.; Gonçalves, Roger; Pereira, Ernesto C.

    2016-01-01

    Here we report supercapacitors fabricated with the layer-by-layer (LBL) technique using two polymers, namely poly(o-methoxyaniline) (POMA) and poly(3-thiophene acetic acid) (PTAA). The electrochemical performances of POMA/PTAA supercapacitors were characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The results were compared with POMA casting film. The specific capacitance of LBL films increases almost linearly with a number of bilayers which were not observed for POMA casting films. The results of this investigation demonstrate that the self-doping effect between POMA and PTAA can change the properties on films and can be successfully used as a supercapacitor technology.

  4. Metallurgical evaluation of a copper-based alloy for dental castings.

    PubMed

    Guastaldi, A C; Lacefield, W R; Leinfelder, K F; Mondelli, J

    1991-08-01

    The present study was designed to evaluate the metallurgical properties of an experimental, low-cost copper-zinc-aluminum-nickel alloy for dental castings. Some specimens were subjected to heat treatment after induction casting. The extent of corrosion was determined by measuring weight loss of specimens stored in a sodium sulfite solution. In the as-cast specimens, tests demonstrated the presence of three phases: the first consisted of copper-zinc-aluminum, the second was similar but lower in copper and aluminum, and the third consisted of an intermetallic compound of manganese-nickel-phosphorus. After heat treatment, the first phase remained relatively constant, the second was converted to Cu3Al, and the third increased in volume. The weight loss from the as-cast specimens was eight times that of the heat-treated specimens. It was concluded that the heat treatment substantially changed the microstructure and improved the corrosion resistance of the experimental alloy. PMID:1882060

  5. Amperometric Biosensor Based on Zirconium Oxide/Polyethylene Glycol/Tyrosinase Composite Film for the Detection of Phenolic Compounds.

    PubMed

    Ahmad, Nor Monica; Abdullah, Jaafar; Yusof, Nor Azah; Ab Rashid, Ahmad Hazri; Abd Rahman, Samsulida; Hasan, Md Rakibul

    2016-01-01

    A phenolic biosensor based on a zirconium oxide/polyethylene glycol/tyrosinase composite film for the detection of phenolic compounds has been explored. The formation of the composite film was expected via electrostatic interaction between hexacetyltrimethylammonium bromide (CTAB), polyethylene glycol (PEG), and zirconium oxide nanoparticles casted on screen printed carbon electrode (SPCE). Herein, the electrode was treated by casting hexacetyltrimethylammonium bromide on SPCE to promote a positively charged surface. Later, zirconium oxide was mixed with polyethylene glycol and the mixture was dropped cast onto the positively charged SPCE/CTAB. Tyrosinase was further immobilized onto the modified SPCE. Characterization of the prepared nanocomposite film and the modified SPCE surface was investigated by scanning electron microscopy (SEM), Electrochemical Impedance Spectroscopy (EIS), and Cyclic voltamogram (CV). The developed biosensor exhibits rapid response for less than 10 s. Two linear calibration curves towards phenol in the concentrations ranges of 0.075-10 µM and 10-55 µM with the detection limit of 0.034 µM were obtained. The biosensor shows high sensitivity and good storage stability for at least 30 days. PMID:27367738

  6. Cerium-based, intermetallic-strengthened aluminum casting alloy: High-volume co-product development

    DOE PAGESBeta

    Sims, Zachary C.; Weiss, D.; McCall, S. K.; McGuire, M. A.; Ott, R. T.; Geer, Tom; Rios, Orlando; Turchi, P. A. E.

    2016-05-23

    Here, several rare earth elements are considered by-products to rare earth mining efforts. By using one of these by-product elements in a high-volume application such as aluminum casting alloys, the supply of more valuable rare earths can be globally stabilized. Stabilizing the global rare earth market will decrease the long-term criticality of other rare earth elements. The low demand for Ce, the most abundant rare earth, contributes to the instability of rare earth extraction. In this article, we discuss a series of intermetallic-strengthened Al alloys that exhibit the potential for new high-volume use of Ce. The castability, structure, and mechanicalmore » properties of binary, ternary, and quaternary Al-Ce based alloys are discussed. We have determined Al-Ce based alloys to be highly castable across a broad range of compositions. Nanoscale intermetallics dominate the microstructure and are the theorized source of the high ductility. In addition, room-temperature physical properties appear to be competitive with existing aluminum alloys with extended high-temperature stability of the nanostructured intermetallic.« less

  7. Extinction-based shading and illumination in GPU volume ray-casting.

    PubMed

    Schlegel, Philipp; Makhinya, Maxim; Pajarola, Renato

    2011-12-01

    Direct volume rendering has become a popular method for visualizing volumetric datasets. Even though computers are continually getting faster, it remains a challenge to incorporate sophisticated illumination models into direct volume rendering while maintaining interactive frame rates. In this paper, we present a novel approach for advanced illumination in direct volume rendering based on GPU ray-casting. Our approach features directional soft shadows taking scattering into account, ambient occlusion and color bleeding effects while achieving very competitive frame rates. In particular, multiple dynamic lights and interactive transfer function changes are fully supported. Commonly, direct volume rendering is based on a very simplified discrete version of the original volume rendering integral, including the development of the original exponential extinction into a-blending. In contrast to a-blending forming a product when sampling along a ray, the original exponential extinction coefficient is an integral and its discretization a Riemann sum. The fact that it is a sum can cleverly be exploited to implement volume lighting effects, i.e. soft directional shadows, ambient occlusion and color bleeding. We will show how this can be achieved and how it can be implemented on the GPU. PMID:22034296

  8. Welding and mechanical properties of cast FAPY (Fe-16 at. % Al-based) alloy slabs

    SciTech Connect

    Sikka, V.K.; Goodwin, G.M.; Alexander, D.J.; Howell, C.R.

    1995-05-01

    This report deals with the welding procedure development and weldment properties of an Fe-16 at. % Al alloy known as FAPY. The welding procedure development was carried out on 12-, 25-, and 51-mm (0.5-, 1-, and 2-in.) -thick plates of the alloy in the as-cast condition. The welds were prepared by using the gas tungsten arc process and filler wire of composition matching the base-metal composition. The preheat temperatures varied from room temperature to 350{degrees}C, and the postweld heat treatment (PWHT) was limited only for 1 h at 750{degrees}C. The welds were characterized by microstructural. analysis and microhardness data. The weldment specimens were machined for Charpy-impact, tensile, and creep properties. The tensile and creep properties of the weldment specimens were essentially the same as that of the base metal. The Charpy-impact properties of the weldment specimens improved with the PWHT and were somewhat lower than previously developed data on the wrought material. Additional work is required on welding of thicker sections, development of PWHT temperatures as a function of section thickness, and mechanical properties.

  9. Cerium-Based, Intermetallic-Strengthened Aluminum Casting Alloy: High-Volume Co-product Development

    NASA Astrophysics Data System (ADS)

    Sims, Zachary C.; Weiss, D.; McCall, S. K.; McGuire, M. A.; Ott, R. T.; Geer, Tom; Rios, Orlando; Turchi, P. A. E.

    2016-07-01

    Several rare earth elements are considered by-products to rare earth mining efforts. By using one of these by-product elements in a high-volume application such as aluminum casting alloys, the supply of more valuable rare earths can be globally stabilized. Stabilizing the global rare earth market will decrease the long-term criticality of other rare earth elements. The low demand for Ce, the most abundant rare earth, contributes to the instability of rare earth extraction. In this article, we discuss a series of intermetallic-strengthened Al alloys that exhibit the potential for new high-volume use of Ce. The castability, structure, and mechanical properties of binary, ternary, and quaternary Al-Ce based alloys are discussed. We have determined Al-Ce based alloys to be highly castable across a broad range of compositions. Nanoscale intermetallics dominate the microstructure and are the theorized source of the high ductility. In addition, room-temperature physical properties appear to be competitive with existing aluminum alloys with extended high-temperature stability of the nanostructured intermetallic.

  10. Cerium-Based, Intermetallic-Strengthened Aluminum Casting Alloy: High-Volume Co-product Development

    NASA Astrophysics Data System (ADS)

    Sims, Zachary C.; Weiss, D.; McCall, S. K.; McGuire, M. A.; Ott, R. T.; Geer, Tom; Rios, Orlando; Turchi, P. A. E.

    2016-05-01

    Several rare earth elements are considered by-products to rare earth mining efforts. By using one of these by-product elements in a high-volume application such as aluminum casting alloys, the supply of more valuable rare earths can be globally stabilized. Stabilizing the global rare earth market will decrease the long-term criticality of other rare earth elements. The low demand for Ce, the most abundant rare earth, contributes to the instability of rare earth extraction. In this article, we discuss a series of intermetallic-strengthened Al alloys that exhibit the potential for new high-volume use of Ce. The castability, structure, and mechanical properties of binary, ternary, and quaternary Al-Ce based alloys are discussed. We have determined Al-Ce based alloys to be highly castable across a broad range of compositions. Nanoscale intermetallics dominate the microstructure and are the theorized source of the high ductility. In addition, room-temperature physical properties appear to be competitive with existing aluminum alloys with extended high-temperature stability of the nanostructured intermetallic.

  11. Application of alcohol based spraying coating on green sand mould for steel casting

    NASA Astrophysics Data System (ADS)

    Xu, Z. L.; Wang, J.; Yang, S. S.; He, Q. L.; Xiong, H. Sh

    2015-12-01

    A kind of coating suitable for green sand steel casting was developed. The practical application showed that the strength of the coating was high enough with no crack and no peeling under room temperature after drying the spraying coating, the performance of the coating for anti-cracking was good under high temperature, and the gas evolution of the coating was low. Using the coating, the casting surfaces finish appeared very good.

  12. 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

  13. Use of gamma-irradiation technology in the manufacture of biopolymer-based packaging films for shelf-stable foods

    NASA Astrophysics Data System (ADS)

    Parra, Duclerc F.; Rodrigues, Juliana A. F. R.; Lugão, Ademar B.

    2005-07-01

    Gamma irradiation is an alternative method for the manufacture of sterilized packaging with increased storage stability and microbiological safety. Biopolymer-based packaging films are a potential solution to many environmental problems that have emerged from the production and accumulation of significant amounts of synthetic polymeric waste. This work was undertaken to verify the effectiveness of low-dose gamma-irradiation in obtaining biopolymer-based packaging films for shelf-stable foods. PHB polyester poly(3-hydroxybutyrate) is an interesting biodegradable polymer that has been intensely investigated as cast and sheet films, with applications in the food industry and medicine. The films obtained are, however, typically brittle, and many scientists have attempted to reduce this brittleness by blending PHB with other polymers. In the present work, PHB was blended with PEG (polyethyleneglycol) to obtain films by the casting method that were then irradiated at a dose rate of 5.72 kGy/h with a 60Co source. Samples were melted at 200 °C and quenched to 0 °C in order to evaluate film crystallinity levels by differential scanning calorimetry (DSC). DSC analyses were performed with the samples (10 mg) under N2 atmosphere, heating from -50 to 200 °C (10 °C min-1), cooling from 200 to -50 °C (10 °C min-1); and heating from -50 to 200 °C (10 °C min-1). The thermal and mechanical resistances of the films after irradiation at low doses (5, 10, 20 kGy) are discussed. Water vapour transmission decreased with increasing irradiation dose, indicating that the films' performance as water vapour barrier had improved. Critical loss of the mechanical properties was observed at 40 kGy.

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

    NASA Astrophysics Data System (ADS)

    Ţălu, Ştefan; Stach, Sebastian; Mahajan, Aman; Pathak, Dinesh; Wagner, Tomas; Kumar, Anshul; Bedi, R. K.; Ţălu, 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 μm2 and 2500 μm2. 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( α) 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.

  15. High-throughput models for exposure-based chemical prioritization in the ExpoCast project.

    PubMed

    Wambaugh, John F; Setzer, R Woodrow; Reif, David M; Gangwal, Sumit; Mitchell-Blackwood, Jade; Arnot, Jon A; Joliet, Olivier; Frame, Alicia; Rabinowitz, James; Knudsen, Thomas B; Judson, Richard S; Egeghy, Peter; Vallero, Daniel; Cohen Hubal, Elaine A

    2013-08-01

    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 program to prioritize chemical inventories for potential hazard. Similar capabilities for estimating exposure potential would support rapid risk-based prioritization for chemicals with limited information; here, we propose a framework for high-throughput exposure assessment. To demonstrate application, an analysis was conducted that predicts human exposure potential for chemicals and estimates uncertainty in these predictions by comparison to biomonitoring data. We evaluated 1936 chemicals using far-field mass balance human exposure models (USEtox and RAIDAR) and an indicator for indoor and/or consumer use. These predictions were compared to exposures inferred by Bayesian analysis from urine concentrations for 82 chemicals reported in the National Health and Nutrition Examination Survey (NHANES). Joint regression on all factors provided a calibrated consensus prediction, the variance of which serves as an empirical determination of uncertainty for prioritization on absolute exposure potential. Information on use was found to be most predictive; generally, chemicals above the limit of detection in NHANES had consumer/indoor use. Coupled with hazard HTS, exposure HTS can place risk earlier in decision processes. High-priority chemicals become targets for further data collection. PMID:23758710

  16. Impact of annealing on the structural and optical properties of methylene green nanostructure films prepared by drop casting

    NASA Astrophysics Data System (ADS)

    El-Menyawy, E. M.; Darwish, A. A. A.; Zedan, I. T.

    2016-05-01

    The methylene green (MG) powder was found to be polycrystalline with the triclinic system. MG films were deposited by drop coating technique. X-ray diffraction and scanning electron microscopy showed that the MG films have nanostructure nature. It is found that the crystal size is increased by annealing. Optical properties of nanostructured MG films were performed in the spectral range from 200 to 2500 nm to determine the optical constants (n and k). The absorption coefficient of the as-deposited film revealed a two indirect allowed optical band gap with values of 1.90 and 3.11 eV, which increased by annealing to 2 and 3.48 eV, respectively. The dispersion of n was discussed in terms of the single oscillator model. The high frequency dielectric constant and the lattice dielectric constant were estimated and found to decreased by annealing.

  17. 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

  18. Starch-based Antimicrobial Films Incorporated with Lauric Acid and Chitosan

    NASA Astrophysics Data System (ADS)

    Salleh, E.; Muhamad, I. I.

    2010-03-01

    Antimicrobial (AM) packaging is one of the most promising active packaging systems. Starch-based film is considered an economical material for antimicrobial packaging. This study aimed at the development of food packaging based on wheat starch incorporated with lauric acid and chitosan as antimicrobial agents. The purpose is to restrain or inhibit the growth of spoilage and/or pathogenic microorganisms that are contaminating foods. The antimicrobial effect was tested on B. substilis and E. coli. Inhibition of bacterial growth was examined using two methods, i.e. zone of inhibition test on solid media and liquid culture test (optical density measurements). The control and AM films (incorporated with chitosan and lauric acid) were produced by casting method. From the observations, AM films exhibited inhibitory zones. Interestingly, a wide clear zone on solid media was observed for B. substilis growth inhibition whereas inhibition for E. coli was not as effective as B. substilis. From the liquid culture test, the AM films clearly demonstrated a better inhibition against B. substilis than E. coli.

  19. Mechanical and barrier properties of starch-based films plasticized with two- or three component deep eutectic solvents.

    PubMed

    Zdanowicz, Magdalena; Johansson, Caisa

    2016-10-20

    The aim of this work was to prepare two- and three-components deep eutectic solvents (DES) and investigate their potential as starch plasticizers. Starch/DES films were prepared via casting method. Mechanical properties, water vapor- and oxygen transmission rates were measured; additionally contact angle and moisture sorption were determined and FTIR analysis was applied on the films. Native potato starch and hydroxypropylated and oxidized starch (HOPS) with common plasticizers (e.g. polyols, urea) and DES were studied. Moreover, influence of three methods of DES introduction and concentration of plasticizer on the films properties were compared. HOPS films were prepared by two methods: as non-cured and cured samples. Some of DESs containing citrate anion exhibited crosslinking ability of polysaccharide matrix. Non-cured HOPS/DES films exhibited more favourable mechanical and barrier properties than cured analogue films. Samples prepared with unmodified potato starch had higher mechanical and barrier properties than films made with HOPS. Starch-based films plasticized with novel DESs with parallel crosslinking activity exhibited satisfactory mechanical and barrier properties. PMID:27474548

  20. 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

  1. Optimization of excess Bi doping to enhance ferroic orders of spin casted BiFeO{sub 3} thin film

    SciTech Connect

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

    2014-06-21

    Multiferroic Bismuth Ferrite (BiFeO{sub 3}) 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 BiFeO{sub 3} 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 BiFeO{sub 3} and Fe{sub 2}O{sub 3} to pure BiFeO{sub 3} phase and, subsequently, to a mixture of BiFeO{sub 3} and Bi{sub 2}O{sub 3} with increase in the concentration of excess Bi from 0% to 15%. BiFeO{sub 3} thin films having low content (0% and 2%) of excess Bi showed the traces of ferromagnetic phase (γ-Fe{sub 2}O{sub 3}). Deterioration in ferroic properties of BiFeO{sub 3} thin films is also observed when prepared with higher content (15%) of excess Bi. Single-phased BiFeO{sub 3} thin film prepared with 5% excess Bi concentration exhibited the soft ferromagnetic hysteresis loops and ferroelectric characteristics with remnant polarization 4.2 μC/cm{sup 2} 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 BiFeO{sub 3} thin films having 5% excess Bi. The results are important to identify optimum excess Bi concentration needed for the formation of single phase BiFeO{sub 3} thin films exhibiting the improved multiferroic properties.

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

    SciTech Connect

    Azenha, Miguel; Magalhaes, Filipe; Faria, Rui; Cunha, Alvaro

    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.

  3. Microstructure Based Modeling of β 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.

  4. 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.

  5. 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.

  6. Treatment of tracheopharyngeal and tracheo-oesophageal fistulas following laryngectomy and fistula classification based on individual silicone casts.

    PubMed

    Herzog, Michael; Lorenz, Kai J; Glien, Alexander; Greiner, Ingo; Plontke, Stefan; Plößl, Sebastian

    2015-10-01

    Persistent tracheopharyngeal (TPF) and tracheo-oesophageal (TEF) fistulas after laryngectomy create a therapeutic challenge. The current classification of TPFs and TEFs is based on clinical experience without detailed anatomical information. In this study, casts of TPFs/TEFs were obtained from 16 patients; these were the first steps in manufacturing customised prostheses. Fistulas were classified according to the shape and dimension of the tracheopharyngeal and tracheo-oesophageal silicone casts and prostheses as well as on epithetic requirements. Four different types of fistulas were classified: Type A, a fistula with a straight axis between the neopharynx and oesophagus; Type B, a fistula with a stenosis of the neopharynx but a straight axis; Type C, the axis between the neopharynx and oesophagus is flexed anteriorly; and Type D, neighbouring structures are absent creating a large defect. This classification system might improve the manufacturing processes of customised prostheses in individual cases with challenging tracheopharyngeal and tracheo-oesophageal fistulas. PMID:25178413

  7. Improved quantitative visualization of hypervelocity flow through wavefront estimation based on shadow casting of sinusoidal gratings.

    PubMed

    Medhi, Biswajit; Hegde, Gopalakrishna M; Gorthi, Sai Siva; Reddy, Kalidevapura Jagannath; Roy, Debasish; Vasu, Ram Mohan

    2016-08-01

    A simple noninterferometric optical probe is developed to estimate wavefront distortion suffered by a plane wave in its passage through density variations in a hypersonic flow obstructed by a test model in a typical shock tunnel. The probe has a plane light wave trans-illuminating the flow and casting a shadow of a continuous-tone sinusoidal grating. Through a geometrical optics, eikonal approximation to the distorted wavefront, a bilinear approximation to it is related to the location-dependent shift (distortion) suffered by the grating, which can be read out space-continuously from the projected grating image. The processing of the grating shadow is done through an efficient Fourier fringe analysis scheme, either with a windowed or global Fourier transform (WFT and FT). For comparison, wavefront slopes are also estimated from shadows of random-dot patterns, processed through cross correlation. The measured slopes are suitably unwrapped by using a discrete cosine transform (DCT)-based phase unwrapping procedure, and also through iterative procedures. The unwrapped phase information is used in an iterative scheme, for a full quantitative recovery of density distribution in the shock around the model, through refraction tomographic inversion. Hypersonic flow field parameters around a missile-shaped body at a free-stream Mach number of ∼8 measured using this technique are compared with the numerically estimated values. It is shown that, while processing a wavefront with small space-bandwidth product (SBP) the FT inversion gave accurate results with computational efficiency; computation-intensive WFT was needed for similar results when dealing with larger SBP wavefronts. PMID:27505389

  8. MOLDS FOR CASTING PLUTONIUM

    DOEpatents

    Anderson, J.W.; Miley, F.; Pritchard, W.C.

    1962-02-27

    A coated mold for casting plutonium comprises a mold base portion of a material which remains solid and stable at temperatures as high as the pouring temperature of the metal to be cast and having a thin coating of the order of 0.005 inch thick on the interior thereof. The coating is composed of finely divided calcium fluoride having a particle size of about 149 microns. (AEC)

  9. Design of freeze-dried Soluplus/polyvinyl alcohol-based film for the oral delivery of an insoluble drug for the pediatric use.

    PubMed

    Shamma, Rehab; Elkasabgy, Nermeen

    2016-01-01

    Spironolactone (SL) is a poorly water-soluble drug. Being poorly soluble affects its dissolution rate which in turn affects its oral bioavailability. This work aimed to prepare freeze-dried SL-Soluplus/polyvinyl alcohol (PVA) oral thin film in an attempt to enhance the drug solubility on one hand and at the same time prepare a solid dosage form convenient for the pediatric use. SL-Soluplus/PVA films were prepared using polyethylene glycol 400 (PEG 400) as a plasticizer applying the solvent-casting technique. The prepared films were evaluated for their thickness, tensile strength, and in vitro dissolution studies. Box-Behnken design (17 runs) was applied to optimize the effects of the formulation variables on the film properties. The optimized film formulation was freeze-dried after casting so as to enhance the drug dissolution. Moreover, the optimized freeze-dried film was re-characterized in vitro and evaluated in vivo in human volunteers to investigate its palatability and satisfaction. The results showed that the optimized formulation composed of 10% polymer concentration containing Soluplus:PVA (0.33:0.66) and plasticized with 30% PEG 400 possessed the highest desirability value (0.836). Freeze-drying of the optimized formulation succeeded to improve SL in vitro dissolution due to the preparation of a more porous film compared to the non-freeze-dried one. In vivo evaluation of the optimized freeze-dried film showed high satisfaction among the participating volunteers concerning the ease of administration and sensation thereafter, where all the film specimens dissolved without the need for water and no film residues remained in the mouth following film dissolution. In conclusion, freeze-dried Soluplus®/PVA-based oral thin film proved to be a successful carrier for the oral delivery of insoluble drugs like SL for pediatrics. PMID:24892631

  10. Caste-based differences in gene expression in the polyembryonic wasp Copidosoma floridanum.

    PubMed

    Donnell, David M; Strand, Michael R

    2006-02-01

    The polyembryonic parasitoid Copidosoma floridanum produces two larval castes, soldiers and reproductives, during development within its host. Soldier larvae defend the brood against competitors while reproductive larvae develop into adult wasps. As with other caste-forming insects, the distinct morphological and behavioral features of soldier and reproductive larvae likely involve differential gene expression. In this study we used a bi-directional suppression subtractive hybridization (SSH) approach to isolate differentially expressed genes from C. floridanum soldier and reproductive larvae. We isolated 230 novel expressed sequence tags (ESTs) from the two subtractions (114 soldier/116 reproductive ESTs). Among these ESTs were sequences with significant similarity to genes coding for serine proteinases, proteinase inhibitors, odorant-binding and chemosensory proteins, and cuticular proteins. Also, three novel genes were isolated that resemble one another in conceptual translation and share the cysteine spacing pattern of short scorpion toxins and insect defensins. Reverse transcription-polymerase chain reaction (RT-PCR) analysis of 20 ESTs from the two libraries indicated that 85% were differentially expressed in one caste or the other. We conclude that our SSH strategy was effective in identifying a number of genes differentially expressed in soldier and reproductive larvae and that several of these genes will be useful in characterizing caste-specific gene networks in C. floridanum. PMID:16431281

  11. 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...

  12. Standard specification for castings, zirconium-base, corrosion resistant, for general application. ASTM standard

    SciTech Connect

    1998-02-01

    This specification is under the jurisdiction of ASTM Committee B-10 on Reactive and Refractory Metals and Alloys and is the direct responsibility of Subcommittee B10.05 on Castings. Current edition approved Oct. 10, 1997 and published February 1998. Originally published as B 752-85. Last previous edition was B 752-91(1995).

  13. 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...

  14. Dynamic shader generation for GPU-based multi-volume ray casting.

    PubMed

    Rössler, Friedemann; Botchen, Ralf P; Ertl, Thomas

    2008-01-01

    Real-time performance for rendering multiple intersecting volumetric objects requires the speed and flexibility of modern GPUs. This requirement has restricted programming of the necessary shaders to GPU experts only. A visualization system that dynamically generates GPU shaders for multi-volume ray casting from a user-definable abstract render graph overcomes this limitation. PMID:18753036

  15. Energy-Saving Melting and Revert Reduction Technology (E-SMARRT): Lost Foam Thin Wall - Feasibility of Producing Lost Foam Castings in Aluminum and Magnesium Based Alloys

    SciTech Connect

    Fasoyinu, Yemi; Griffin, John A.

    2014-03-31

    With the increased emphasis on vehicle weight reduction, production of near-net shape components by lost foam casting will make significant inroad into the next-generation of engineering component designs. The lost foam casting process is a cost effective method for producing complex castings using an expandable polystyrene pattern and un-bonded sand. The use of un-bonded molding media in the lost foam process will impose less constraint on the solidifying casting, making hot tearing less prevalent. This is especially true in Al-Mg and Al-Cu alloy systems that are prone to hot tearing when poured in rigid molds partially due to their long freezing range. Some of the unique advantages of using the lost foam casting process are closer dimensional tolerance, higher casting yield, and the elimination of sand cores and binders. Most of the aluminum alloys poured using the lost foam process are based on the Al-Si system. Very limited research work has been performed with Al-Mg and Al-Cu type alloys. With the increased emphasis on vehicle weight reduction, and given the high-strength-to-weight-ratio of magnesium, significant weight savings can be achieved by casting thin-wall (≤ 3 mm) engineering components from both aluminum- and magnesium-base alloys.

  16. 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

  17. Effect of solvent casting on reduced entanglement density in thin films studied by ellipsometry and neutron reflection

    SciTech Connect

    Sauer, B.B.; Walsh, D.J. . Central Research and Development)

    1994-01-17

    Neutron reflection (NR) and spectroscopic ellipsometry (SE) were used for the investigation of the interfaces between films of poly(vinyl methyl ether) (PVME, glass transition temperature (T[sub g]) = [minus]31 C) and polystyrene (PS, T[sub g][approximately] 105 C). The transport of PVME into PS at temperatures below the glass transition of PS was highly non-Fickian. The linear dependence of the front propagation with time, along with the high activation energy for transport indicates some similarities to classical case 2 transport of solvent into polymer glasses. The variation of PVME transport rate with PS molecular weight (MW) illustrates one significant difference as compared to classical case 2 transport. The strong dependence of PVME transport rate on PS MW is attributed to the MW dependence of the rate of swelling and dissolution of PS in the swollen front region. It was also found that the transport rate (front velocity) of PVME into PS depended strongly on the temperature and time of preannealing of the single spin coated PS layer. Preannealing at temperature well above T[sub g] for higher MW PS films was necessary. Birefringence measurements on PS films proved that internal stress was not a factor. A systematic MW study indicated that the major factor was the reduced entanglement density due to spinning of PS films from solution.

  18. 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.

  19. Chitosan-based mucoadhesive films containing 5-aminolevulinic acid for buccal cancer's treatment.

    PubMed

    Costa, Irina dos Santos Miranda; Abranches, Renata Pereira; Garcia, Maria Teresa Junqueira; Pierre, Maria Bernadete Riemma

    2014-11-01

    Photodynamic therapy (PDT) is a relatively new method to treat various kinds of tumors, including those of the oral cavity. The topical 5-ALA-PDT treatment for tumors of the oral mucosa is preferred, since when administered systemically, there is a general photosensitization drawback in the patient. However, 5-ALA is a hydrophilic molecule and its penetration and retention is limited by topical route, including oral mucosa. We propose a topical delivery system of chitosan-based mucoadhesive film, aiming to promote greater retention of 5-ALA in tissue. The chitosan (CHT) films (4% w/w) were prepared using the solvent evaporation/casting technique. They were tested without 5-ALA resulting in permeability to water vapor (W.V.P=2.15-8.54 g mm/(h cm(2)Pa) swelling ∼300.0% (±10.5) at 4 h or 24 h and in vitro residence time >24 h for all tests. CHT films containing 10.0% (w/w) 5-ALA have resulted in average weight of 0.22 g and thickness of 0.608 mm as suitable characteristics for oral application. In the presence of CHT films both in vitro permeation and retention of 5-ALA (1.0% or 10.0%) were increased. However, 10.0% 5-ALA presented highest values of permeation and retention (∼4 and 17 times respectively, compared to propylene glycol vehicle). On the other hand, in vitro mucoadhesion of CHT films was decreased (18.2-fold and 3.1-fold) by 5-ALA addition (1.0% or 10.0% respectively). However, CHT film containing 10.0% of 5-ALA can be a potential delivery system for topical use in the treatment of tumors of the oral cavity using PDT because it favored the retention of 5-ALA in this tissue and has shown convenient mucoadhesion. PMID:25190225

  20. 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

  1. Birefringence gradient development during drying of solution cast functional films and their mechanical, optical and gas barrier properties

    NASA Astrophysics Data System (ADS)

    Yucel, Orcun

    For the first time, the development of optical anisotropy gradient as a result of solvent evaporation for poly (amide-imide) (PAI) solution in Dimethylacetamide (DMAc) was investigated. Experiments were carried out using real time optical measurement with spectral birefringence technique coupled with off-line optical techniques such as Abbe refractometer and optical compensator method. Drying process induced temporal evolution of non-uniform out of plane birefringence profile through the thickness direction while in plane birefringence remained zero. The highest birefringence was observed at the substrate-solution interface at early stages of drying. Beyond a critical time, the formation of highly oriented layer was observed at the air-solution interface. This oriented layer progresses through the thickness direction as the solvent concentration is disproportionately reduced in these regions. Abbe refractometer results confirmed the anisotropy is preserved at longer drying times, air-solution interface birefringence becoming higher compared to substrate-solution interface. Overall, observations obtained by real-time measurement system agreed with off-line measurements. In additon, multifunctional single and triple-layer films exhibiting flexibility, high modulus and high gas barrier properties were developed using a soluble polyamide-imide (PAI) in dimethylacetamide (DMAc) with ammonium-modified montmorillonite (MMT, Cloisite 30B) mineral clay. The drying behavior and associated anisotropy development were determined real-time, using a newly developed real-time measurement system. Increase in organoclay content resulted in higher viscosity values. This behavior was reversed at high shear rates. Out-of-plane birefringence development occurred earlier for thinner neat samples caused by increased depletion rate of solvent. Addition of organoclay content resulted in a decrease in evaporation rate of solvent due to planar orientation of well exfoliated nanoplatelets as

  2. Sensitivity of linear CCD array based film scanners used for film dosimetry

    SciTech Connect

    Devic, Slobodan; Wang Yizhen; Tomic, Nada; Podgorsak, Ervin B.

    2006-11-15

    Film dosimetry is commonly performed by using linear CCD array transmission optical densitometers. However, these devices suffer from a variation in response along the detector array. If not properly corrected for, this nonuniformity may lead to significant overestimations of the measured dose as one approaches regions close to the edges of the scanning region. In this note, we present measurements of the spatial response of an AGFA Arcus II document scanner used for radiochromic film dosimetry. Results and methods presented in this work can be generalized to other CCD based transmission scanners used for film dosimetry employing either radiochromic or radiographic films.

  3. Sensitivity of linear CCD array based film scanners used for film dosimetry.

    PubMed

    Devic, Slobodan; Wang, Yi-Zhen; Tomic, Nada; Podgorsak, Ervin B

    2006-11-01

    Film dosimetry is commonly performed by using linear CCD array transmission optical densitometers. However, these devices suffer from a variation in response along the detector array. If not properly corrected for, this nonuniformity may lead to significant overestimations of the measured dose as one approaches regions close to the edges of the scanning region. In this note, we present measurements of the spatial response of an AGFA Arcus II document scanner used for radiochromic film dosimetry. Results and methods presented in this work can be generalized to other CCD based transmission scanners used for film dosimetry employing either radiochromic or radiographic films. PMID:17153378

  4. Reproducibility of ZrO2-based freeze casting for biomaterials.

    PubMed

    Naleway, Steven E; Fickas, Kate C; Maker, Yajur N; Meyers, Marc A; McKittrick, Joanna

    2016-04-01

    The processing technique of freeze casting has been intensely researched for its potential to create porous scaffold and infiltrated composite materials for biomedical implants and structural materials. However, in order for this technique to be employed medically or commercially, it must be able to reliably produce materials in great quantities with similar microstructures and properties. Here we investigate the reproducibility of the freeze casting process by independently fabricating three sets of eight ZrO2-epoxy composite scaffolds with the same processing conditions but varying solid loading (10, 15 and 20 vol.%). Statistical analyses (One-way ANOVA and Tukey's HSD tests) run upon measurements of the microstructural dimensions of these composite scaffold sets show that, while the majority of microstructures are similar, in all cases the composite scaffolds display statistically significant variability. In addition, composite scaffolds where mechanically compressed and statistically analyzed. Similar to the microstructures, almost all of their resultant properties displayed significant variability though most composite scaffolds were similar. These results suggest that additional research to improve control of the freeze casting technique is required before scaffolds and composite scaffolds can reliably be reproduced for commercial or medical applications. PMID:26838830

  5. 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.

  6. A Winning Cast

    NASA Technical Reports Server (NTRS)

    2001-01-01

    Howmet Research Corporation was the first to commercialize an innovative cast metal technology developed at Auburn University, Auburn, Alabama. With funding assistance from NASA's Marshall Space Flight Center, Auburn University's Solidification Design Center (a NASA Commercial Space Center), developed accurate nickel-based superalloy data for casting molten metals. Through a contract agreement, Howmet used the data to develop computer model predictions of molten metals and molding materials in cast metal manufacturing. Howmet Metal Mold (HMM), part of Howmet Corporation Specialty Products, of Whitehall, Michigan, utilizes metal molds to manufacture net shape castings in various alloys and amorphous metal (metallic glass). By implementing the thermophysical property data from by Auburn researchers, Howmet employs its newly developed computer model predictions to offer customers high-quality, low-cost, products with significantly improved mechanical properties. Components fabricated with this new process replace components originally made from forgings or billet. Compared with products manufactured through traditional casting methods, Howmet's computer-modeled castings come out on top.

  7. Sprue design alterations and its effect on the properties of base metal alloy castings: An in vitro study

    PubMed Central

    Geetha Prabhu, K. R.; Prabhu, R.; Maheswari, H.; Eswaran, M. A.; Phanikrishna, G.; Deepthi, B.

    2015-01-01

    Introduction: To study the effect of various sprue designs on the properties of base metal alloy castings. The base metal alloys are extensively used for their excellent properties such as an increase in hardness, high melting range, high elastic modulus, its compatibility with ceramic material and low cost. However, to improve the properties of the base metal alloys is an ongoing research leading to various modifications in their fabrication procedure – which include sprue designs and their mode of attachment to the wax pattern. Aims and Objectives: Study compared the effect of three sprue designs viz. conical sprue, cylindrical sprue and bottleneck sprue on the properties of mass and microhardness of base metal alloy castings. Materials and Methods: A prefabricated wax mesh pattern was selected for the fabrication of the alloy test samples in the study. The cylindrical sprue design was connected to the mesh pattern with a straight attachment. The bottleneck sprue design was connected to the mesh pattern with a constricted attachment. The conical sprue design was connected to the mesh pattern with a flared attachment. In this manner, ten samples for each of the three different sprue designs were prepared. Results: The obtained value for mass and microhardness were subjected to statistical analysis. ANOVA test was performed to determine the difference between the sprue designs. Conclusion: The bottleneck sprue, conical sprue, and cylindrical sprue designs did not exert any apparent influence on the mass and microhardness. PMID:26538911

  8. Creep-rupture behavior of a developmental cast-iron-base alloy for use up to 800 deg C

    NASA Technical Reports Server (NTRS)

    Titran, Robert H.; Scheuermann, Coulson M.

    1987-01-01

    A promising iron-base cast alloy is being developed as part of the DOE/NASA Stirling Engine Systems Project under contract DEN 3-282 with the United Technologies Research Center. This report presents the results of a study at the Lewis Research Center of the alloy's creep-rupture properties. The alloy was tested under a variety of conditions and was found to exhibit the normal 3-stage creep response. The alloy compared favorably with others being used or under consideration for the automotive Stirling engine cylinder/regenerator housing.

  9. Antimicrobial and physicochemical properties of chitosan-HPMC-based films.

    PubMed

    Möller, Heike; Grelier, Stéphane; Pardon, Patrick; Coma, Véronique

    2004-10-20

    To prepare composite films from biopolymers with anti-listerial activity and moisture barrier properties, the antimicrobial efficiency of chitosan-hydroxy propyl methyl cellulose (HPMC) films, chitosan-HPMC films associated with lipid, and chitosan-HPMC films chemically modified by cross-linking were evaluated. In addition, the physicochemical properties of composite films were evaluated to determine their potential for food applications. The incorporation of stearic acid into the composite chitosan-HPMC film formulation decreased water sensitivity such as initial solubility in water and water drop angle. Thus, cross-linking of composite chitosan-HPMC, using citric acid as the cross-linking agent, led to a 40% reduction in solubility in water. The water vapor transfer rate of HPMC film, approximately 270 g x m(-2) x day(-1) x atm(-1), was improved by incorporating chitosan and was further reduced 40% by the addition of stearic acid and/or cross-linking. Anti-listerial activity of films was determined on solid medium by a numeration technique. Chitosan-HPMC-based films, with and without stearic acid, inhibited the growth of Listeria monocytogenes completely. On the other hand, a loss of antimicrobial activity after chemical cross-linking modification was observed. FTIR and 13C NMR analyses were then conducted in order to study a potential chemical modification of biopolymers such as a chemical reaction with the amino group of chitosan. To complete the study, the mechanical properties of composite films were determined from tensile strength assays. PMID:15479027

  10. 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

    2015-07-28

    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

  11. Piezoresistivity of graphene-based thin films

    NASA Astrophysics Data System (ADS)

    Raveendran Nair, Rahul; Navoselov, K. S.; Jiang, Da; Neubeck, Soren; Ponomarenko, Leonid; Geim, A. K.

    2009-03-01

    Large-scale production of graphene films is of particular interest because of graphene's extraordinary electronic, mechanical and optical properties. We report the properties of graphene films produced by spraying or spinning of a graphene suspension obtained by ultrasound cleavage of graphite in organic solvents, the route that does not involve graphene oxide [1]. Wafer-scale uniform films of overlapping submicron graphene crystallites were made on transparent substrates and exhibited sheet resistivity of a few kφ with more than 80% transmission with respect to white light. Electric measurements and Raman studies suggest that the films are p-doped. In particular, we have investigated the piezoresistive effect in such films by depositing them on flexible plastic substrates. Fully reversible changes in the resistance were observed as a function of strain that could exceed 8% before the films started loosing their continuity. The piezoresistive gauge factor was up to ˜30 for our films. [1] Peter Blake et al., Nano Lett. 2008, 8,1704-1708.

  12. 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.

  13. Electrocaloric devices based on thini-film heat switches

    SciTech Connect

    Epstein, Richard I; Malloy, Kevin J

    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.

  14. Casting defects in low-pressure die-cast aluminum alloy wheels

    NASA Astrophysics Data System (ADS)

    Zhang, B.; Cockcroft, S. L.; Maijer, D. M.; Zhu, J. D.; Phillion, A. B.

    2005-11-01

    Defects in automotive aluminum alloy casting continue to challenge metallurgists and production engineers as greater emphasis is placed on product quality and production cost. A range of casting-related defects found in low-pressure die-cast aluminum wheels were examined metallographically in samples taken from several industrial wheel-casting facilities. The defects examined include macro- and micro- porosity, entrained oxide films, and exogenous oxide inclusions. Particular emphasis is placed on the impact of these defects with respect to the three main casting-related criteria by which automotive wheel quality are judged: wheel cosmetics, air-tightness, and wheel mechanical performance.

  15. Ion beam-based characterization of multicomponent oxide thin films and thin film layered structures

    SciTech Connect

    Krauss, A.R.; Rangaswamy, M.; Lin, Yuping; Gruen, D.M.; Schultz, J.A.; Schmidt, H.K.; Chang, R.P.H.

    1992-11-01

    Fabrication of thin film layered structures of multi-component materials such as high temperature superconductors, ferroelectric and electro-optic materials, and alloy semiconductors, and the development of hybrid materials requires understanding of film growth and interface properties. For High Temperature Superconductors, the superconducting coherence length is extremely short (5--15 {Angstrom}), and fabrication of reliable devices will require control of film properties at extremely sharp interfaces; it will be necessary to verify the integrity of thin layers and layered structure devices over thicknesses comparable to the atomic layer spacing. Analytical techniques which probe the first 1--2 atomic layers are therefore necessary for in-situ characterization of relevant thin film growth processes. However, most surface-analytical techniques are sensitive to a region within 10--40 {Angstrom} of the surface and are physically incompatible with thin film deposition and are typically restricted to ultra high vacuum conditions. A review of ion beam-based analytical methods for the characterization of thin film and multi-layered thin film structures incorporating layers of multicomponent oxides is presented. Particular attention will be paid to the use of time-of-flight techniques based on the use of 1- 15 key ion beams which show potential for use as nondestructive, real-time, in-situ surface diagnostics for the growth of multicomponent metal and metal oxide thin films.

  16. Structural, morphological and optical properties of PEDOT:PSS/QDs nano-composite films prepared by spin-casting

    NASA Astrophysics Data System (ADS)

    Najeeb, Mansoor Ani; Abdullah, Shahino Mah; Aziz, Fakhra; Ahmad, Zubair; Rafique, Saqib; Wageh, S.; Al-Ghamdi, Ahmed A.; Sulaiman, Khaulah; Touati, Farid; Shakoor, R. A.; Al-Thani, N. J.

    2016-09-01

    This paper describes the structural, morphological and optical properties of the nano-composite of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and quantum dots (QDs). The ZnSe and CdSe QDs have been synthesized, with the aid of Mercaptoacetic acid (MAA), by a colloidal method with an average size of ~5 to 7 nm. QDs have been embedded in PEDOT:PSS using a simple solution processing approach and has been deposited as thin films by spin coating technique. The QDs embedded PEDOT:PSS enhances the light absorption spectra of samples, prominently in terms of absorption intensity which may consequently improve sensitivity of the optoelectronic devices.

  17. Breaking through the strength-ductility trade-off dilemma in an Al-Si-based casting alloy.

    PubMed

    Dang, B; Zhang, X; Chen, Y Z; Chen, C X; Wang, H T; Liu, F

    2016-01-01

    Al-Si-based casting alloys have a great potential in various industrial applications. Common strengthening strategies on these alloys are accompanied inevitably by sacrifice of ductility, known as strength-ductility trade-off dilemma. Here, we report a simple route by combining rapid solidification (RS) with a post-solidification heat treatment (PHT), i.e. a RS + PHT route, to break through this dilemma using a commercial Al-Si-based casting alloy (A356 alloy) as an example. It is shown that yield strength and elongation to failure of the RS + PHT processed alloy are elevated simultaneously by increasing the cooling rate upon RS, which are not influenced by subsequent T6 heat treatment. Breaking through the dilemma is attributed to the hierarchical microstructure formed by the RS + PHT route, i.e. highly dispersed nanoscale Si particles in Al dendrites and nanoscale Al particles decorated in eutectic Si. Simplicity of the RS + PHT route makes it being suitable for industrial scaling production. The strategy of engineering microstructures offers a general pathway in tailoring mechanical properties of other Al-Si-based alloys. Moreover, the remarkably enhanced ductility of A356 alloy not only permits strengthening further the material by work hardening but also enables possibly conventional solid-state forming of the material, thus extending the applications of such an alloy. PMID:27502444

  18. Breaking through the strength-ductility trade-off dilemma in an Al-Si-based casting alloy

    NASA Astrophysics Data System (ADS)

    Dang, B.; Zhang, X.; Chen, Y. Z.; Chen, C. X.; Wang, H. T.; Liu, F.

    2016-08-01

    Al-Si-based casting alloys have a great potential in various industrial applications. Common strengthening strategies on these alloys are accompanied inevitably by sacrifice of ductility, known as strength-ductility trade-off dilemma. Here, we report a simple route by combining rapid solidification (RS) with a post-solidification heat treatment (PHT), i.e. a RS + PHT route, to break through this dilemma using a commercial Al-Si-based casting alloy (A356 alloy) as an example. It is shown that yield strength and elongation to failure of the RS + PHT processed alloy are elevated simultaneously by increasing the cooling rate upon RS, which are not influenced by subsequent T6 heat treatment. Breaking through the dilemma is attributed to the hierarchical microstructure formed by the RS + PHT route, i.e. highly dispersed nanoscale Si particles in Al dendrites and nanoscale Al particles decorated in eutectic Si. Simplicity of the RS + PHT route makes it being suitable for industrial scaling production. The strategy of engineering microstructures offers a general pathway in tailoring mechanical properties of other Al-Si-based alloys. Moreover, the remarkably enhanced ductility of A356 alloy not only permits strengthening further the material by work hardening but also enables possibly conventional solid-state forming of the material, thus extending the applications of such an alloy.

  19. Breaking through the strength-ductility trade-off dilemma in an Al-Si-based casting alloy

    PubMed Central

    Dang, B.; Zhang, X.; Chen, Y. Z.; Chen, C. X.; Wang, H. T.; Liu, F.

    2016-01-01

    Al-Si-based casting alloys have a great potential in various industrial applications. Common strengthening strategies on these alloys are accompanied inevitably by sacrifice of ductility, known as strength-ductility trade-off dilemma. Here, we report a simple route by combining rapid solidification (RS) with a post-solidification heat treatment (PHT), i.e. a RS + PHT route, to break through this dilemma using a commercial Al-Si-based casting alloy (A356 alloy) as an example. It is shown that yield strength and elongation to failure of the RS + PHT processed alloy are elevated simultaneously by increasing the cooling rate upon RS, which are not influenced by subsequent T6 heat treatment. Breaking through the dilemma is attributed to the hierarchical microstructure formed by the RS + PHT route, i.e. highly dispersed nanoscale Si particles in Al dendrites and nanoscale Al particles decorated in eutectic Si. Simplicity of the RS + PHT route makes it being suitable for industrial scaling production. The strategy of engineering microstructures offers a general pathway in tailoring mechanical properties of other Al-Si-based alloys. Moreover, the remarkably enhanced ductility of A356 alloy not only permits strengthening further the material by work hardening but also enables possibly conventional solid-state forming of the material, thus extending the applications of such an alloy. PMID:27502444

  20. Isothermal and non-isothermal crystallization kinetics of PVA + ionic liquid [BDMIM][BF4]-based polymeric films

    NASA Astrophysics Data System (ADS)

    Saroj, A. L.; Chaurasia, S. K.; Kataria, Shalu; Singh, R. K.

    2016-06-01

    The effect of ionic liquid (IL), 1-butyl-2,3-dimethylimidazolium tetrafluoroborate [BDMIM][BF4], on crystallization behavior of poly(vinyl alcohol) (PVA) has been studied by isothermal and non-isothermal differential scanning calorimetry techniques. The PVA + IL based polymer electrolyte films have been prepared using solution casting technique. To describe the isothermal and non-isothermal crystallization kinetics, several kinetic equations have been employed on PVA + IL based films. There is strong dependence of the peak crystallization temperature (Tc), relative degree of crystallity (Xt), half-time of crystallization (t1/2), crystallization rate constants (Avrami Kt and Tobin AT), and Avrami (n) and Tobin (nT) exponents on the cooling rate and IL loading.

  1. Chimerical categories: caste, race, and genetics.

    PubMed

    Sabir, Sharjeel

    2003-12-01

    Is discrimination based on caste equivalent to racism? This paper explores the complex relationship between genetic, race and caste. It also discusses the debate over the exclusion of a discussion of caste-based discrimination at the 2001 World Conference against Racism, Racial Discrimination, Xenophobia and Related Intolerance held in Durban, South Africa. PMID:14768649

  2. 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.

  3. Ductility improvement of direct-cast gamma TiAl-based alloy sheet

    SciTech Connect

    Hanamura, Toshihiro; Hashimoto, Keizo

    1997-12-31

    For improving the room temperature tensile ductility of direct-cast gamma TiAl sheets without affecting their high-temperature strength, direct sheet casting with TiB{sub 2} particle dispersion is employed and conducted. The TiB{sub 2} addition and rapid cooling results in the formation of a fine equiaxed grain microstructure with an average grain size of {approximately}10{micro}m, contributing to the increase in the room temperature ductility to 2.1% with the high-temperature tensile strength kept at about 200 MPa. This improvement of room-temperature ductility is attributable to the following fact. The high oxygen content of this material, about 2,500 wt.ppm, is not harmful to the tensile ductility when the oxygen is in the solid solution of the {alpha}{sub 2} lamellar phase or in oxide particles, which are fine enough not to cause brittleness to the matrix. From these findings, a principle is proposed that oxygen is not harmful to the ductility of gamma TiAl when its microstructure containing oxygen is fine enough.

  4. Stereology-based modeling and analysis of equiaxed solidification in casting simulations

    SciTech Connect

    Marsh, S.P.; Richards, L.E.; Banerjee, D.

    1995-12-31

    A formalism has been developed for expressing micromodels in a consistent manner using stereological parameters to quantify the geometric characteristics of the developing microstructure. This approach provides a robust and physically consistent method for coupling local micromodels with the macroscopic fields, and allows direct implementation of micromodels having various forms into discrete numerical simulations. The macroscopic state variables at each finite-element node serve as global constraints on the local unit volume of microstructure, which allows information to be exchanged between the two regimes and greatly simplifies the incorporation of multiple mechanisms that occur during a single casting process. This approach has been used to develop a model of equiaxed solidification that combines the mechanisms of nucleation, dendritic growth, temperature-dependent solidification, and coarsening. Numerical results of this model are presented for an Al-7% Si brake drum casting and compared with a stereological analysis of the observed microstructure. Measurements of the specific surface area, S{sub v}, of the dendritic structure show very good agreement with simulation results derived from unfitted model parameters.

  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

  6. On the performance of low pressure die-cast Al-Cu based automotive alloys: Role of additives

    NASA Astrophysics Data System (ADS)

    Zaki, Gergis Adel

    The present study focuses on the effect of alloying elements, namely, strontium (Sr), titanium (Ti), zirconium (Zr), scandium (Sc) and silver(Ag) individually or in combination, on the performance of a newly developed Al-2%Cu based alloy. A total of thirteen alloy compositions were used in the study. Tensile test bar castings were prepared employing the low pressure die casting (LPDC) technique. The test bars were solution heat treated at 495°C for 8 hours, followed by quenching in warm water, and then subjected to different isochronal aging treatments using an aging time of 5 hours and aging temperatures of 155°C, 180°C, 200°C, 240°C and 300°C. Tensile testing of as-cast and heat-treated test bars was carried out at room temperature using a strain rate of 4 x 10-4s-1. Five test bars were used per alloy composition/condition. Hardness measurements were also carried out on these alloys using a Brinell hardness tester. The microstructures of selected samples were examined using optical microscopy and electron probe microanalysis (EPMA). The results showed that adding Ti in the amount of 0.15 wt% in the form of Al-5%Ti-1%B master alloy is sufficient to refine the grains in the cast structure in the presence of 200 ppm Sr (0.02 wt%). Addition of Zr and Sc did not contribute further to the grain refining effect. The main role of addition of these two elements appeared in the formation of complex compounds with Al and Ti. Their presence resulted in extending the aging temperature range before the onset of softening. Mathematical analysis of the hardness and tensile data was carried out using the Minitab statistical software program. It was determined that the alloy containing (0.5wt% Zr + 0.15wt% Ti) is the most effective in maximizing the alloy tensile strength over the range of aging temperatures, from 155°C to 300°C. Addition of Ag is beneficial at high aging temperatures, in the range of 240°C-300°C. However, it is less effective compared to the (Zr + Ti

  7. 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

  8. 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

  9. Nanocrystalline silicon based thin film solar cells

    NASA Astrophysics Data System (ADS)

    Ray, Swati

    2012-06-01

    Amorphous silicon solar cells and panels on glass and flexible substrate are commercially available. Since last few years nanocrystalline silicon thin film has attracted remarkable attention due to its stability under light and ability to absorb longer wavelength portion of solar spectrum. For amorphous silicon/ nanocrystalline silicon double junction solar cell 14.7% efficiency has been achieved in small area and 13.5% for large area modules internationally. The device quality nanocrystalline silicon films have been fabricated by RF and VHF PECVD methods at IACS. Detailed characterizations of the materials have been done. Nanocrystalline films with low defect density and high stability have been developed and used as absorber layer of solar cells.

  10. 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

  11. Preparation, mechanical property and cytocompatibility of freeze-cast porous calcium phosphate ceramics reinforced by phosphate-based glass.

    PubMed

    Yang, Yanqiu; He, Fupo; Ye, Jiandong

    2016-12-01

    In this study, phosphate-based glass (PG) was used as a sintering aid for freeze-cast porous biphasic calcium phosphate (BCP) ceramic, which was sintered under a lower temperature (1000°C). The phase composition, pore structure, compressive strength, and cytocompatibility of calcium phosphate composite ceramics (PG-BCP) were evaluated. The results indicated that PG additive reacted with calcium phosphate during the sintering process, forming β-Ca2P2O7; the ions of sodium and magnesium from PG partially substituted the calcium sites of β-calcium phosphate in BCP. The PG-BCP showed good cytocompatibility. The pore width of the porous PG-BCP ceramics was around 50μm, regardless of the amount of PG sintering aid. As the content of PG increased from 0wt.% to 15wt.%, the compressive strength of PG-BCP increased from 0.02 MP to 0.28MPa. When the PG additive was 17.5wt.%, the compressive strength of PG-BCP dramatically increased to 5.66MPa. Addition of 15wt.% PG was the critical point for the properties of PG-BCP. PG is considered as an effective sintering aid for freeze-cast porous bioceramics. PMID:27612796

  12. Effect of gamma radiation on the physico-chemical properties of alginate-based films and beads

    NASA Astrophysics Data System (ADS)

    Huq, Tanzina; Khan, Avik; Dussault, Dominic; Salmieri, Stephane; Khan, Ruhul A.; Lacroix, Monique

    2012-08-01

    Alginate solution (3%, w/v) was prepared using deionized water from its powder. Then the solution was exposed to gamma radiation (0.1-25 kGy). The alginate films were prepared by solution casting. It was found that gamma radiation has strong effect on alginate solution. At low doses, mechanical strength of the alginate films improved but after 5 kGy dose, the strength started to decrease. The mechanism of alginate radiolysis in aqueous solution is discussed. Film formation was not possible from alginate solution at doses >5 kGy. The mechanical properties such as puncture strength (PS), puncture deformation (PD), viscoelasticity (Y) coefficient of the un-irradiated films were investigated. The values of PS, PD and Y coefficient of the films were 333 N/mm, 3.20 mm and 27%, respectively. Alginate beads were prepared from 3% alginate solution (w/v) by ionotropic gelation method in 5% CaCl2 solution. The rate of gel swelling improved in irradiated alginate-based beads at low doses (up to 0.5 kGy).

  13. Modeling and optimization of antibacterial activity of the chitosan-based hydrogel films using central composite design.

    PubMed

    Lahooti, Behnaz; Khorram, Mohammad; Karimi, Gholamreza; Mohammadi, Aliakbar; Emami, Amir

    2016-10-01

    In the present study, hydrogel films composed of chitosan-poly(vinyl alcohol)-gelatin-thyme honey were successfully prepared by casting method, and their anti-bacterial properties were modeled and optimized. Antibacterial properties of the prepared films were analyzed by applying agar diffusion method. Staphylococcus aureus and Pseudomonas aeruginosa were tested as Gram-positive and Gram-negative bacteria, respectively. In order to obtain the composition of the film with maximum inhibition zone against both above-mentioned bacterial strains, the experiments were designed using response surface methodology based on five-level central composite design with four parameters, including concentrations of chitosan, poly(vinyl alcohol), gelatin, and honey. The results indicated that the prepared samples had good antibacterial activities against these two studied bacteria strains. Response surface method is conducted to develop mathematical models for process responses. Variance analysis on the experimental data shows that inhibition zone can be predicted effectively with quadratic models. In addition, swelling properties and rate of water vapor transmission of the prepared hydrogel films were studied. Due to the successful results, this hydrogel film has an excellent potential to be explored further as a wound healing material. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 2544-2553, 2016. PMID:27241899

  14. 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

  15. Methods for preparing colloidal nanocrystal-based thin films

    DOEpatents

    Kagan, Cherie R.; Fafarman, Aaron T.; Choi, Ji-Hyuk; Koh, Weon-kyu; Kim, David K.; Oh, Soong Ju; Lai, Yuming; Hong, Sung-Hoon; Saudari, Sangameshwar Rao; Murray, Christopher B.

    2016-05-10

    Methods of exchanging ligands to form colloidal nanocrystals (NCs) with chalcogenocyanate (xCN)-based ligands and apparatuses using the same are disclosed. The ligands may be exchanged by assembling NCs into a thin film and immersing the thin film in a solution containing xCN-based ligands. The ligands may also be exchanged by mixing a xCN-based solution with a dispersion of NCs, flocculating the mixture, centrifuging the mixture, discarding the supernatant, adding a solvent to the pellet, and dispersing the solvent and pellet to form dispersed NCs with exchanged xCN-ligands. The NCs with xCN-based ligands may be used to form thin film devices and/or other electronic, optoelectronic, and photonic devices. Devices comprising nanocrystal-based thin films and methods for forming such devices are also disclosed. These devices may be constructed by depositing NCs on to a substrate to form an NC thin film and then doping the thin film by evaporation and thermal diffusion.

  16. ShakeCast Manual

    USGS Publications Warehouse

    Lin, Kuo-Wan; Wald, David J.

    2008-01-01

    ShakeCast is a freely available, post-earthquake situational awareness application that automatically retrieves earthquake shaking data from ShakeMap, compares intensity measures against users? facilities, and generates potential damage assessment notifications, facility damage maps, and other Web-based products for emergency managers and responders.

  17. 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.

  18. 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.

  19. CASTING APPARATUS

    DOEpatents

    Gray, C.F.; Thompson, R.H.

    1958-09-23

    An apparatus is described for casting small quantities of uranlum. It consists of a crucible having a hole in the bottom with a mold positioned below. A vertical rcd passes through the hole in the crucible and has at its upper end a piercing head adapted to break the oxide skin encasing a molten uranium body. An air tight cylinder surrounds the crucible and mold, and is arranged to be evacuated.

  20. 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

  1. 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.

  2. 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

  3. 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

  4. CIR Casting System for making transtibial sockets.

    PubMed

    Wu, Yeongchi; Casanova, Hector R; Reisinger, Kim D; Smith, William K; Childress, Dudley S

    2009-03-01

    This paper describes a new casting system for transtibial socket fabrication. Like the earlier CIR Sand Casting System, the CIR Casting System is based on the 'dilatancy' principle that is similar to the packaging process for coffee beans by which loose beans become a solid mass when a vacuum is applied. The main difference from the CIR Sand Casting System is that the CIR Casting System uses light-weight, polystyrene beads in place of silica sand as the primary material for casting the negative mold. The formed negative mold can be converted into a positive sand model for modification and socket formation. With the new plaster-less casting system, the prosthetist can fabricate a transtibial prosthesis in about one hour. It reduces the set-up cost, overall weight and size of the casting system, and increases portability for service in remote areas. The System also creates minimal waste and is energy-conserving and environmentally-friendly. PMID:19235060

  5. Fabrication of hierarchically structured superhydrophobic PDMS surfaces by Cu and CuO casting

    NASA Astrophysics Data System (ADS)

    Migliaccio, Christopher P.; Lazarus, Nathan

    2015-10-01

    Poly(dimethylsiloxane) (PDMS) films decorated with hierarchically structured pillars are cast from large area copper and copper oxide negative molds. The molds are fabricated using a single patterning step and electroplating. The process of casting structured PDMS films is simpler and cheaper than alternatives based on deep reactive ion etching or laser roughening of bulk silicone. Texture imparted to the pillars from the mold walls renders the PDMS films superhydrophobic, with the contact angle/hysteresis of the most non-wetting surfaces measuring 164°/9° and 158°/10° for surfaces with and without application of a low surface energy coating. The usefulness of patterned PDMS films as a "self-cleaning" solar cell module covering is demonstrated and other applications are discussed.

  6. Electroslag component casting. [Nickel aluminide

    SciTech Connect

    Sikka, V.K.

    1986-01-01

    This project is directed toward the development of electroslag-casting (ESC) technology for use in coal conversion components such as valve bodies, pump housings, and pipe fittings. The aim is also to develop a sufficient data base to permit electroslag casting to become an ASME Code-accepted process. It is also intended to transfer the ESC process technology to private industry. A total of 32 electroslag castings of 2.25Cr-1Mo, 9Cr-1Mo, type 316, and nickel aluminide were procured from four facilities for evaluation (Table 1). The most complex castings procured during this program were the valve bodies shown in Figure 2. The castings were subjected to various heat treatments (Table 2), checked for chemical composition uniformity from top to bottom, and subjected to macrostructural evaluation and mechanical properties testing. Results are discussed. 10 refs., 7 figs., 3 tabs.

  7. 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.

  8. Linear Microbolometric Array Based on VOx Thin Film

    NASA Astrophysics Data System (ADS)

    Chen, Xi-Qu

    2010-05-01

    In this paper, a linear microbolometric array based on VOx thin film is proposed. The linear microbolometric array is fabricated by using micromachining technology, and its thermo-sensitive VOx thin film has excellent infrared response spectrum and TCR characteristics. Integrated with CMOS circuit, an experimentally prototypical monolithic linear microbolometric array is designed and fabricated. The testing results of the experimental linear array show that the responsivity of linear array can approach 18KV/W and is potential for infrared image systems.

  9. Effects of silicon on the oxidation, hot-corrosion, and mechanical behavior of two cast nickel-base superalloys

    NASA Technical Reports Server (NTRS)

    Miner, R. V., Jr.

    1977-01-01

    Cast specimens of nickel-base superalloys 713C and Mar-M200 with nominal additions of 0, 0.5, and 1 wt% Si were evaluated for oxidation and corrosion resistance, tensile and stress-rupture properties, microstructure, and phase relations. Results are compared with those of an earlier study of the effects of Si in B-1900. Si had similar effects on all three superalloys. It improves oxidation resistance but the improvement in 713C and Mar-M200 was considerably less than in B-1900. Hot-corrosion resistance is also improved somewhat. Si is, however, detrimental to mechanical properties, in particular, rupture strength and tensile ductility. Si has two obvious microstructural effects. It increases the amount of gamma-prime precipitated in eutectic nodules and promotes a Mo(Ni,Si)2 Laves phase in the alloys containing Mo. These microstructural effects do not appear responsible for the degradation of mechanical properties, however.

  10. Interfacial characteristics of squeeze-cast SiC reinforced AZ91D magnesium-based composites

    SciTech Connect

    Lo, J.; Carpenter, G.J.C.; Charest, M.

    1996-10-01

    The method of producing magnesium-based composites with silicon carbide (SiC) particulates embedded in the matrix of magnesium AZ91D alloy by the squeeze-casting technique are described. This method involves the fabrication of a SiC particulate preform and the subsequent squeezing of molten magnesium into the preform. In this study, alumina, aluminum phosphate and a proprietary binder were used for the fabrication of SiC particulate preforms. The procedures employed in the fabrication of SiC/AZ91D composites are presented, together with the results of characterization of the composites using optical and transmission electron microscopy. Special attention is given to the reaction products in the bulk alloy and at the interfaces between SiC particles and the AZ91D matrix alloy.

  11. Functionally graded alumina-based thin film systems

    DOEpatents

    Moore, John J.; Zhong, Dalong

    2006-08-29

    The present invention provides coating systems that minimize thermal and residual stresses to create a fatigue- and soldering-resistant coating for aluminum die casting dies. The coating systems include at least three layers. The outer layer is an alumina- or boro-carbide-based outer layer that has superior non-wettability characteristics with molten aluminum coupled with oxidation and wear resistance. A functionally-graded intermediate layer or "interlayer" enhances the erosive wear, toughness, and corrosion resistance of the die. A thin adhesion layer of reactive metal is used between the die substrate and the interlayer to increase adhesion of the coating system to the die surface.

  12. Fabrication of wrist-like SMA-based actuator by double smart soft composite casting

    NASA Astrophysics Data System (ADS)

    Rodrigue, Hugo; Wei, Wang; Bhandari, Binayak; Ahn, Sung-Hoon

    2015-12-01

    A new manufacturing method for smart soft composite (SSC) actuators that consists of double casting a SSC actuator to produce an actuator with non-linear shape memory alloy (SMA) wire positioning is proposed. This method is used to manufacture a tube-shaped SSC actuator in which the SMA wires follow the curvature of the tube and is capable of pure-twisting deformations while sustaining a cantilever load. The concept is tested by measuring the maximum twisting angle and a simple control method is proposed to control the twisting angle of the actuator. Then, a soft robotic wrist with a length of 18 cm is built, its load-carrying capability is tested by measuring the cantilever force required for deforming the actuator, and its load-carrying capability during actuation is tested by loading one end with different objects and actuating the actuator. This wrist actuator shows good repeatability, is capable of twisting deformations up to 25° while holding objects weighing 100 g, and can sustain loads above 2 N without undergoing buckling.

  13. Venous Thrombosis Risk after Cast Immobilization of the Lower Extremity: Derivation and Validation of a Clinical Prediction Score, L-TRiP(cast), in Three Population-Based Case–Control Studies

    PubMed Central

    Nemeth, Banne; van Adrichem, Raymond A.; van Hylckama Vlieg, Astrid; Bucciarelli, Paolo; Martinelli, Ida; Baglin, Trevor; Rosendaal, Frits R.; le Cessie, Saskia; Cannegieter, Suzanne C.

    2015-01-01

    Background Guidelines and clinical practice vary considerably with respect to thrombosis prophylaxis during plaster cast immobilization of the lower extremity. Identifying patients at high risk for the development of venous thromboembolism (VTE) would provide a basis for considering individual thromboprophylaxis use and planning treatment studies. The aims of this study were (1) to investigate the predictive value of genetic and environmental risk factors, levels of coagulation factors, and other biomarkers for the occurrence of VTE after cast immobilization of the lower extremity and (2) to develop a clinical prediction tool for the prediction of VTE in plaster cast patients. Methods and Findings We used data from a large population-based case–control study (MEGA study, 4,446 cases with VTE, 6,118 controls without) designed to identify risk factors for a first VTE. Cases were recruited from six anticoagulation clinics in the Netherlands between 1999 and 2004; controls were their partners or individuals identified via random digit dialing. Identification of predictor variables to be included in the model was based on reported associations in the literature or on a relative risk (odds ratio) > 1.2 and p ≤ 0.25 in the univariate analysis of all participants. Using multivariate logistic regression, a full prediction model was created. In addition to the full model (all variables), a restricted model (minimum number of predictors with a maximum predictive value) and a clinical model (environmental risk factors only, no blood draw or assays required) were created. To determine the discriminatory power in patients with cast immobilization (n = 230), the area under the curve (AUC) was calculated by means of a receiver operating characteristic. Validation was performed in two other case–control studies of the etiology of VTE: (1) the THE-VTE study, a two-center, population-based case–control study (conducted in Leiden, the Netherlands, and Cambridge, United Kingdom

  14. Characterisation and modelling of defect formation in direct-chill cast AZ80 alloy

    SciTech Connect

    Mackie, D.; Robson, J.D.; Withers, P.J.; Turski, M.

    2015-06-15

    Wrought magnesium alloys for demanding structural applications require high quality defect free cast feedstock. The aim of this study was to first identify and characterise typical defects in direct chill cast magnesium–aluminium–zinc (AZ) alloy billet and then use modelling to understand the origins of these defects so they can be prevented. Defects were first located using ultrasonic inspection and were then characterised using X-ray computed tomography (XCT) and serial sectioning, establishing the presence of oxide films and intermetallic particles Al{sub 8}Mn{sub 5} in all defects. A model was developed to predict the flow patterns and growth kinetics of the intermetallic phases during casting, which influence the formation of defects. Simulation of the growth of the intermetallic particles demonstrated that precipitation from the liquid occurs in the mould. The combination of the entrained oxide films and intermetallic particles recirculates in the liquid metal and continues to grow, until large enough to settle, which is predicted to occur at the centre of the mould where the flow is the slowest. Based on these predictions, strategies to reduce the susceptibility to defect formation are suggested. - Highlights: • Casting defects in magnesium direct chill casting have been imaged and characterised in 3-dimensions. • The occurrences of co-located clusters of particles and oxide films have been characterised and explained. • A coupled model has been developed to help interpret the observed trend for defects located towards the centre of billets.

  15. Influence of SiO2 surface energy on the performance of organic field effect transistors based on highly oriented, zone-cast layers of a tetrathiafulvalene derivative

    NASA Astrophysics Data System (ADS)

    Miskiewicz, Pawel; Kotarba, Sylwia; Jung, Jaroslaw; Marszalek, Tomasz; Mas-Torrent, Marta; Gomar-Nadal, Elba; Amabilino, David B.; Rovira, Concepcio; Veciana, Jaume; Maniukiewicz, Waldemar; Ulanski, Jacek

    2008-09-01

    In this paper we present that the surface energy of silicon dioxide employed as the dielectric in bottom gate organic field effect transistors has large impact on the device performance. By the use of the zone-casting simple solution processing technique, we ensured reproducibility of active layer preparation confirmed by the atomic force microscopy and x-ray diffraction that showed high crystalline quality. Electrical measurements revealed that charge carrier mobility based on highly ordered zone-cast tetrakis-(octadecylthio)-tetrathiafulvalene layer was increased 30 times to 0.2 cm2/V s, when dielectric surface energy decreased from 51.8 to 40.1 mN/m.

  16. Instant Casting Movie Theater: The Future Cast System

    NASA Astrophysics Data System (ADS)

    Maejima, Akinobu; Wemler, Shuhei; Machida, Tamotsu; Takebayashi, Masao; Morishima, Shigeo

    We have developed a visual entertainment system called “Future Cast” which enables anyone to easily participate in a pre-recorded or pre-created film as an instant CG movie star. This system provides audiences with the amazing opportunity to join the cast of a movie in real-time. The Future Cast System can automatically perform all the processes required to make this possible, from capturing participants' facial characteristics to rendering them into the movie. Our system can also be applied to any movie created using the same production process. We conducted our first experimental trial demonstration of the Future Cast System at the Mitsui-Toshiba pavilion at the 2005 World Exposition in Aichi Japan.

  17. Development and Evaluation of Cefadroxil Drug Loaded Biopolymeric Films Based on Chitosan-Furfural Schiff Base

    PubMed Central

    Dixit, Ritu B.; Uplana, Rahul A.; Patel, Vishnu A.; Dixit, Bharat C.; Patel, Tarosh S.

    2010-01-01

    Cefadroxil drug loaded biopolymeric films of chitosan-furfural schiff base were prepared by reacting chitosan with furfural in presence of acetic acid and perchloric acid respectively for the external use. Prepared films were evaluated for their strength, swelling index, thickness, drug content, uniformity, tensile strength, percent elongation, FTIR spectral analysis and SEM. The results of in vitro diffusion studies revealed that the films exhibited enhanced drug diffusion as compared to the films prepared using untreated chitosan. The films also demonstrated good to moderate antibacterial activities against selective gram positive and gram negative bacteria. PMID:21179325

  18. Predicting dermal penetration for ToxCast chemicals using in silico estimates for diffusion in combination with physiologically based pharmacokinetic (PBPK) modeling.

    EPA Science Inventory

    Predicting dermal penetration for ToxCast chemicals using in silico estimates for diffusion in combination with physiologically based pharmacokinetic (PBPK) modeling.Evans, M.V., Sawyer, M.E., Isaacs, K.K, and Wambaugh, J.With the development of efficient high-throughput (HT) in ...

  19. 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 (αCRP). 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 (αCRP-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 (αCRP-Ag) were delineated. The immunosensor exhibited an impedance response to αCRP-Ag concentration in a linear range from 10 ng to 10 μg mL-1.

  20. Casting materials

    DOEpatents

    Chaudhry, Anil R.; Dzugan, Robert; Harrington, Richard M.; Neece, Faurice D.; Singh, Nipendra P.

    2011-06-14

    A foam material comprises a liquid polymer and a liquid isocyanate which is mixed to make a solution that is poured, injected or otherwise deposited into a corresponding mold. A reaction from the mixture of the liquid polymer and liquid isocyanate inside the mold forms a thermally collapsible foam structure having a shape that corresponds to the inside surface configuration of the mold and a skin that is continuous and unbroken. Once the reaction is complete, the foam pattern is removed from the mold and may be used as a pattern in any number of conventional casting processes.

  1. Steel castings by the electroslag casting technique

    NASA Astrophysics Data System (ADS)

    Sikka, V. K.; Mitchell, A.

    1984-10-01

    Electroslag casting facilities in Canada and the United States were reviewed. Several value body castings of 2 1/4 Cr-1 Mo, 9 Cr-1 Mo, and 18% Cr-8% Ni (Mo) steels were made at the University of British Columbia facility. These castings were examined for surface finish, chemical segregation, and macrostructure in the as-cast condition and after various heat treatments. Castings were subjected to tensile, charpy impact, and creep testing. Results of these tests were compared with similar data on wrought material and where applicable, with data on sand castings.

  2. Steel castings by the electroslag casting technique

    SciTech Connect

    Sikka, V.K.; Mitchell, A.

    1984-10-01

    Electroslag casting facilities in Canada and the United States were reviewed. Several valve body castings of 2 1/4 Cr-1 Mo, 9 Cr-1 Mo, and 18% Cr-8% Ni(Mo) steels were made at the University of British Columbia facility. These castings were examined for surface finish, chemical segregation, and macrostructure in the as-cast condition and after various heat treatments. Castings were subjected to tensile, Charpy impact, and creep testing. Results of these tests were compared with similar data on wrought material and, where applicable, with data on sand castings. 22 figures.

  3. SUBTLEX-ESP: Spanish Word Frequencies Based on Film Subtitles

    ERIC Educational Resources Information Center

    Cuetos, Fernando; Glez-Nosti, Maria; Barbon, Analia; Brysbaert, Marc

    2011-01-01

    Recent studies have shown that word frequency estimates obtained from films and television subtitles are better to predict performance in word recognition experiments than the traditional word frequency estimates based on books and newspapers. In this study, we present a subtitle-based word frequency list for Spanish, one of the most widely spoken…

  4. AtCAST3.0 update: a web-based tool for analysis of transcriptome data by searching similarities in gene expression profiles.

    PubMed

    Kakei, Yusuke; Shimada, Yukihisa

    2015-01-01

    In transcriptome experiments, the experimental conditions (e.g. mutants and/or treatments) cause transcriptional changes. Identifying experimental conditions that induce similar or opposite transcriptional changes can be useful to identify experimental conditions that affect the same biological process. AtCAST (http://atpbsmd.yokohama-cu.ac.jp) is a web-based tool to analyze the relationship between experimental conditions among transcriptome data. Users can analyze 'user's transcriptome data' of a new mutant or a new chemical compound whose function remains unknown to generate novel biological hypotheses. This tool also allows for mining of related 'experimental conditions' from the public microarray data, which are pre-included in AtCAST. This tool extracts a set of genes (i.e. module) that show significant transcriptional changes and generates a network graph to present related transcriptome data. The updated AtCAST now contains data on >7,000 microarrays, including experiments on various stresses, mutants and chemical treatments. Gene ontology term enrichment (GOE) analysis is introduced to assist the characterization of transcriptome data. The new AtCAST supports input from multiple platforms, including the 'Arabisopsis gene 1.1 ST array', a new microarray chip from Affymetrix and RNA sequencing (RNA-seq) data obtained using next-generation sequencing (NGS). As a pilot study, we conducted microarray analysis of Arabidopsis under auxin treatment using the new Affymetrix chip, and then analyzed the data in AtCAST. We also analyzed RNA-seq data of the pifq mutant using AtCAST. These new features will facilitate analysis of associations between transcriptome data obtained using different platforms. PMID:25505006

  5. Effects of plasticizers on sorption and optical properties of gum cordia based edible film.

    PubMed

    Haq, Muhammad Abdul; Jafri, Feroz Alam; Hasnain, Abid

    2016-06-01

    The present study aimed to characterize a biodegradable film produced from the polysaccharide of an indigenous plant Cordia myxa. Effect of plasticizer type (Glycerol, Sorbitol, PEG200 and PEG 400) and concentration (0-30 %) was studied on sorption and optical properties of the casted film. Increase in plasticizer concentration resulted in increase in equilibrium moisture content of the film and was supported by GAB model of sorption indicating that isotherms were of Type II. The monolayer value increased with the increase in plasticizer concentration with a peak of 0.93 g.g-1 for glycerol. Addition of plasticizers improved the total color (ΔE) with glycerol showing the highest effects. All films showed resistance to UV light in the range of 280-200 nm. The polysaccharide of the fruit of C.myxa can be used to prepare an edible film with improved properties as compared to other available edible coatings. PMID:27478216

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

    NASA Astrophysics Data System (ADS)

    Nolli, Paolo

    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.

  7. As-cast uranium-molybdenum based metallic fuel candidates and the effects of carbon addition

    NASA Astrophysics Data System (ADS)

    Blackwood, Van Stephen

    The objective of this research was to develop and recommend a metallic nuclear fuel candidate that lowered the onset temperature of gamma phase formation comparable or better than the uranium-10 wt. pct. molybdenum alloy, offered a solidus temperature as high or higher than uranium-10 wt. pct. zirconium (1250°C), and stabilized the fuel phase against interaction with iron and steel at least as much as uranium-10 wt. pct. zirconium stabilized the fuel phase. Two new as-cast alloy compositions were characterized to assess thermal equilibrium boundaries of the gamma phase field and the effect of carbon addition up to 0.22 wt. pct. The first system investigated was uranium- x wt. pct. M where x ranged between 5-20 wt. pct. M was held at a constant ratio of 50 wt. pct. molybdenum, 43 wt. pct. titanium, and 7 wt. pct. zirconium. The second system investigated was the uranium-molybdenum-tungsten system in the range 90 wt. pct. uranium - 10 wt. pct. molybdenum - 0 wt. pct. tungsten to 80 wt. pct. uranium - 10 wt. pct. molybdenum - 10 wt. pct. tungsten. The results showed that the solidus temperature increased with increased addition of M up to 12.5 wt. pct. for the uranium-M system. Alloy additions of titanium and zirconium were removed from uranium-molybdenum solid solution by carbide formation and segregation. The uranium-molybdenum-tungsten system solidus temperature increased to 1218°C at 2.5 wt. pct. with no significant change in temperature up to 5 wt. pct. tungsten suggesting the solubility limit of tungsten had been reached. Carbides were observed with surrounding areas enriched in both molybdenum and tungsten. The peak solidus temperatures for the alloy systems were roughly the same at 1226°C for the uranium-M system and 1218°C for the uranium-molybdenum-tungsten system. The uranium-molybdenum-tungsten system required less alloy addition to achieve similar solidus temperatures as the uranium-M system.

  8. Gadolinium nitride films deposited using a PEALD based process

    NASA Astrophysics Data System (ADS)

    Fang, Ziwen; Williams, Paul A.; Odedra, Rajesh; Jeon, Hyeongtag; Potter, Richard J.

    2012-01-01

    Gadolinium nitride films have been deposited on Si(100) using a plasma-enhanced ALD (PEALD) based process. The deposition was carried out using tris(methylcyclopentadienyl)gadolinium {Gd(MeCp) 3} and remote nitrogen plasma, separated by argon pulses. Films were deposited at temperatures between 150 and 300 °C and capped with tantalum nitride to prevent post-deposition oxidation. Film composition was initially assessed using EDX and selected samples were subsequently depth profiled using medium energy ion scattering (MEIS) or AES. X-ray diffraction appears to show that the films are effectively amorphous. Films deposited at 200 °C were found to have a Gd:N ratio close to 1:1 and a low oxygen incorporation (˜5%). Although the growth was affected by partial thermal decomposition of the Gd(MeCp) 3, it was still possible to obtain smooth (Ra.=˜0.7 nm) films with good thickness uniformity (97%). Less successful attempts to deposit gadolinium nitride using thermal ALD with ammonia or mono-methyl-hydrazine are also reported.

  9. Slip-Cast Superconductive Parts

    NASA Technical Reports Server (NTRS)

    Wise, Stephanie A.; Buckley, John D.; Vasquez, Peter; Buck, Gregory M.; Hicks, Lana P.; Hooker, Matthew W.; Taylor, Theodore D.

    1993-01-01

    Complex shapes fabricated without machining. Nonaqueous slip-casting technique used to form complexly shaped parts from high-temperature superconductive materials like YBa(2)Cu(3)O(7-delta). Such parts useful in motors, vibration dampers, and bearings. In process, organic solvent used as liquid medium. Ceramic molds made by lost-wax process used instead of plaster-of-paris molds, used in aqueous slip-casting but impervious to organic solvents and cannot drain away liquid medium. Organic-solvent-based castings do not stick to ceramic molds as they do to plaster molds.

  10. The effect of grain refinement on the room-temperature ductility of as-cast Fe{sub 3}Al-based alloys

    SciTech Connect

    Viswanathan, S.; Andleigh, V.K.; McKamey, C.G.

    1995-08-01

    Fe{sub 3}Al-based alloys exhibit poor room-temperature ductility in the as-cast condition. In this study, the effect of grain refinement of the as-cast alloy on room-temperature ductility was investigated. Small melts of Fe-28 at. % Al-5 at. % Cr were inoculated with various alloying additions and cast into a 50- x 30- x 30-mm graphite mold. The resulting ingots were examined metallographically for evidence of grain refinement, and three-point bend tests were conducted on samples to assess the effect on room-temperature ductility. Ductility was assumed to correlate with the strain corresponding to the maximum stress obtained in the bend test. The results showed that titanium was extremely effective in grain refinement, although it severely embrittled the alloy in contents exceeding 1%. Boron additions strengthened the alloy significantly, while carbon additions reduced both the strength and ductility. The best ductility was found in an alloy containing titanium, boron, and carbon. In order to verify the results of the grain refinement study, vacuum-induction melts of selected compositions were prepared and cast into a larger 25- x 150- x 100-mm graphite mold. Tensile specimens were machined from the ingots, and specimens were tested at room temperature. The results of the tensile tests agreed with the results of the grain refinement study; in addition, the addition of molybdenum was found to significantly increase room-temperature tensile ductility over that of the base alloy.

  11. MEMS-based microstructures for nanomechanical characterization of thin films

    NASA Astrophysics Data System (ADS)

    Boé, A.; Safi, A.; Coulombier, M.; Fabrègue, D.; Pardoen, T.; Raskin, J.-P.

    2009-11-01

    The measurement of mechanical properties of thin films is a major issue for the design of reliable microelectronic devices, microsensors or thin coatings. New simple microstructures actuated through the release of internally stressed long beams made of high temperature, low pressure chemical vapour deposition silicon nitride have been developed to test under uniaxial tension submicron thin film material specimens. The relative displacement between a fixed and a moving cursor is used to determine the strain applied to the specimen. The stress is inferred based on the mismatch strain and Young's modulus of the silicon nitride actuator beam. By multiplying the tensile test microstructures with different lengths, the full stress-strain curve characterizing the thin material sample is generated from which the elastic stiffness, yield strength, ductility and fracture stress can be extracted. The potential of the method is demonstrated through applications on both brittle and ductile thin films. The Young's modulus of 238 GPa for a 373 nm thick silicon nitride film is extracted and size effects are observed for the yield strength of pure aluminium with a value of 220 and 550 MPa, respectively, for 373 and 205 nm thick films. An original variant of the procedure based on this new test microstructure for measuring Young's modulus is also presented.

  12. USGS ShakeCast

    USGS Publications Warehouse

    Wald, David; Lin, Kuo-Wan

    2007-01-01

    Automating, Simplifying, and Improving the Use of ShakeMap for Post-Earthquake Decisionmaking and Response. ShakeCast is a freely available, post-earthquake situational awareness application that automatically retrieves earthquake shaking data from ShakeMap, compares intensity measures against users facilities, and generates potential damage assessment notifications, facility damage maps, and other Web-based products for emergency managers and responders.

  13. Sixty Years of Casting Research

    NASA Astrophysics Data System (ADS)

    Campbell, John

    2015-11-01

    The 60 years of solidification research since the publication of Chalmer's constitutional undercooling in 1953 has been a dramatic advance of understanding which has and continues to be an inspiration. In contrast, 60 years of casting research has seen mixed fortunes. One of its success stories relates to improvements in inoculation of gray irons, and another to the discovery of spheroidal graphite iron, although both of these can be classified as metallurgical rather than casting advances. It is suggested that true casting advances have dated from the author's lab in 1992 when a critical surface turbulence condition was defined for the first time. These last 20 years have seen the surface entrainment issues of castings developed to a sufficient sophistication to revolutionize the performance of light alloy and steel foundries. However, there is still a long way to go, with large sections of the steel and Ni-base casting industries still in denial that casting defects are important or even exist. The result has been that special ingots are still cast poorly, and shaped casting operations have suffered massive losses. For secondary melted and cast materials, electro-slag remelting has the potential to be much superior to expensive vacuum arc remelting, which has cost our aerospace and defense industries dearly over the years. This failure to address and upgrade our processing of liquid metals is a serious concern, since the principle entrainment defect, the bifilm, is seen as the principle initiator of cracks in metals; in general, bifilms are the Griffith cracks that initiate failures by cracking. A new generation of crack resistant metals and engineering structures can now be envisaged.

  14. Solidification Conditions and Microstructure in Continuously Cast Aluminum

    NASA Astrophysics Data System (ADS)

    Buxmann, K.; Gold, E.

    1982-04-01

    The well-known relationship between cell size or dendrite spacing and local solidification time gives the possibility of calculating the thermal parameters of solidification from the microstructure of the as-cast product. As a basis for such calculations, the dendrite spacing of different aluminum castings (DC cast ingots of different diameters, cast in conventional and electromagnetic molds; cast strip from roll casters, belt casters, and block casters; and Properzi cast rod) has been measured through their cross sections. Based on these measurements, a qualitative discussion of the thermal conditions during the solidification of these products is given, and the influence of a variation in the casting conditions discussed.

  15. 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.

  16. 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 μm) 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 μm 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

  17. Ferroelectric memory element based on thin film field effect transistor

    NASA Astrophysics Data System (ADS)

    Poghosyan, A. R.; Aghamalyan, N. R.; Elbakyan, E. Y.; Guo, R.; Hovsepyan, R. K.

    2013-09-01

    We report the preparation and investigation of ferroelectric field effect transistors (FET) using ZnO:Li films with high field mobility of the charge carriers as a FET channel and as a ferroelectric active element simultaneously. The possibility for using of ferroelectric FET based on the ZnO:Li films in the ZnO:Li/LaB6 heterostructure as a bi-stable memory element for information recording is shown. The proposed ferroelectric memory structure does not manifest a fatigue after multiple readout of once recorded information.

  18. Diffractive Optical Elements based in Diamond Like Carbon (DLC) films

    NASA Astrophysics Data System (ADS)

    Sparvoli, M. Marina; Mansano, Ronaldo D.

    2008-04-01

    In this work was developed a Diffractive Optical Elements (DOEs) based in amorphous hydrogenated carbon (Diamond Like Carbon) films. DOEs can be built in large scale with high reproducibility and eliminating almost stages used in optical elements tradicional fabrication, as abrasion and burnishing. These devices had been built by the etching of DLC deposited by sputtering process. The characterizations of these devices are realized by optical analyzes with a 633 nm HeNe laser. The DLC films roughness and etch rate after process were measured by high step meter.

  19. Bimorph micro heat engines based on carbon nanotube freestanding films

    NASA Astrophysics Data System (ADS)

    Ikuno, Takashi; Fukano, Tatsuo; Higuchi, Kazuo; Takeda, Yasuhiko

    2015-11-01

    We have found that lightweight bimorph strips consisting of multiwalled carbon nanotube freestanding films (MWNT-FSFs) and Ni thin films exhibit a continuous bending-stretching motion on a hot plate even below the temperature of 100 °C in an environment at room temperature. In fact, the Ni/MWNT-FSFs exhibited this motion at a temperature difference of as small as 5 °C. The requirements of this motion have been qualitatively elucidated by a simulation based on a relaxation time approximation.

  20. 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.

  1. Switchable mirrors based on nickel-magnesium films

    NASA Astrophysics Data System (ADS)

    Richardson, T. J.; Slack, J. L.; Armitage, R. D.; Kostecki, R.; Farangis, B.; Rubin, M. D.

    2001-05-01

    An 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 co-sputtering from Ni and Mg targets are mirror-like in appearance and have low visible transmittance. Upon exposure to hydrogen gas or on cathodic polarization 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.

  2. 36 CFR 1237.30 - How do agencies manage records on nitrocellulose-base and cellulose-acetate base film?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... film as specified in Department of Transportation regulations (49 CFR 172.101, Hazardous materials... records on nitrocellulose-base and cellulose-acetate base film? 1237.30 Section 1237.30 Parks, Forests... and cellulose-acetate base film? (a) The nitrocellulose base, a substance akin to gun cotton,...

  3. 36 CFR 1237.30 - How do agencies manage records on nitrocellulose-base and cellulose-acetate base film?

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... film as specified in Department of Transportation regulations (49 CFR 172.101, Hazardous materials... records on nitrocellulose-base and cellulose-acetate base film? 1237.30 Section 1237.30 Parks, Forests... and cellulose-acetate base film? (a) The nitrocellulose base, a substance akin to gun cotton,...

  4. 36 CFR 1237.30 - How do agencies manage records on nitrocellulose-base and cellulose-acetate base film?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... film as specified in Department of Transportation regulations (49 CFR 172.101, Hazardous materials... records on nitrocellulose-base and cellulose-acetate base film? 1237.30 Section 1237.30 Parks, Forests... and cellulose-acetate base film? (a) The nitrocellulose base, a substance akin to gun cotton,...

  5. 36 CFR 1237.30 - How do agencies manage records on nitrocellulose-base and cellulose-acetate base film?

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... film as specified in Department of Transportation regulations (49 CFR 172.101, Hazardous materials... records on nitrocellulose-base and cellulose-acetate base film? 1237.30 Section 1237.30 Parks, Forests... and cellulose-acetate base film? (a) The nitrocellulose base, a substance akin to gun cotton,...

  6. Vertical Conducting Nanodomains Self-Assembled from Poly(3-hexylthiophene)-Based Diblock Copolymer Thin Films

    SciTech Connect

    Y Lee; S Kim; H Yang; M Jang; S Hwang; H Lee; K Baek

    2011-12-31

    We have synthesized {pi}-conjugated poly(3-hexyl thiophene)-block-poly(methyl methacrylate) (P3HT-b-PMMA) with a P3HT molecular weight of 11 kDa and a PMMA volume fraction of 0.53, which potentially has several organic electronic applications. Its phase-separation behavior was investigated for various thicknesses cast from organic solvents. When cast onto 300 nm thick SiO{sub 2} dielectrics from toluene, in which the P3HT segments have limited solubility, the P3HT-b-PMMA films consist of nanofibrillar self-assemblies of laterally {pi}-stacked P3HT chains. In contrast, the P3HT segments were found to be highly mobile in chlorobenzene, generating a typical phase-separation morphology consisting of vertically conducting P3HT nanodomains on these dielectrics. As the thickness of the cast films increased, however, the topmost surface becomes covered with {pi}-conjugated nanofibrils that are laterally oriented with respect to the surface. Due to the anisotropic domain orientations of P3HT, top-gate organic field-effect transistors (OFETs) containing the P3HT-b-PMMA films exhibited enhanced electrical performance compared to bottom-gate OFETs.

  7. Thin Wall Iron Castings

    SciTech Connect

    J.F. Cuttino; D.M. Stefanescu; T.S. Piwonka

    2001-10-31

    Results of an investigation made to develop methods of making iron castings having wall thicknesses as small as 2.5 mm in green sand molds are presented. It was found that thin wall ductile and compacted graphite iron castings can be made and have properties consistent with heavier castings. Green sand molding variables that affect casting dimensions were also identified.

  8. Solvent casting flow from slot die

    NASA Astrophysics Data System (ADS)

    Lee, Semi; Nam, Jaewook

    2015-11-01

    A continuous solvent casting method using a slot die can precisely control the film thickness by adjusting the operating conditions, such as the belt speed and pumping rate, not the liquid property. Therefore, it is a suitable method for high precision continuous film production. In this particular method, the dope, or casting solution, is pumped through the feed slot to form a short curtain between the die and the moving belt. Although this method is widely used in producing films for various applications, it is difficult to find indepth analyses of such flow. In this study, we developed a finite element computational model for the steady-state two-dimensional sovent casting flow from the slot die. The effect of die configurations, rheological properties and operating conditions on the behavior and shape of the gas/liquid interfaces and the location of the dynamic contact line, which is the place where the dope meets the moving belt, were investigated.

  9. Reconstruction and Quantitative Characterization of Multiphase, Multiscale Three-Dimensional Microstructure of a Cast Al-Si Base Alloy

    NASA Astrophysics Data System (ADS)

    Singh, H.; Gokhale, A. M.; Mao, Y.; Tewari, A.; Sachdev, A. K.

    2009-12-01

    The serial sectioning technique is well known for the reconstruction of three-dimensional (3D) microstructures of opaque materials. In recent years, techniques also have been developed for the reconstruction of high-fidelity, large-volume segments of 3D microstructures that use montage serial sections and robot-assisted automated acquisitions of montage serial sections. This article reports the reconstruction of the multiphase, multiscale 3D microstructure of a permanent mold cast unmodified Al-12 wt pct Si-1 wt pct Ni base alloy that contains eutectic Si platelets, coarse primary polyhedral Si particles, Fe-rich script intermetallic particles, and pores. These constituents are segmented, reconstructed, rendered, and characterized in three dimensions. The estimated 3D microstrucutral attributes include the distribution of eutectic platelet thickness; the mean volume, mean surface area, and mean thickness of the eutectic Si platelets; the mean volume and the mean surface area of the polyhedral primary Si particles; and the mean number of faces, edges, and corners on the polyhedral primary Si particles.

  10. Effects of composition and testing conditions on oxidation behavior of four cast commercial nickel-base superalloys

    NASA Technical Reports Server (NTRS)

    Lowell, C. E.; Probst, H. B.

    1974-01-01

    Four cast nickel-base superalloys were oxidized at 1000 and 1100 C for times up to 100 hr in static air and a Mach 1 gas stream. The oxidation resistance was judged by weight change, metal thickness loss, depletion-zone formation, and oxide formation and morphology. The alloys which formed mostly nickel aluminate (NiAl2O4) and aluminum oxide (Al2O3) (B-1900, VIA, and to a lesser extent 713C) were more oxidation resistant. Poorer oxidation resistance was associated with the appearance of chromium sesquioxide (Cr2O3) and chromite spinel (738X). Refractory metal content had little effect on oxidation resistance. Refractory metals appeared in the scale as tapiolite (NiM2O6, where M represents the refractory metal). Thermal cycling in static air appeared to supply sufficient data for the evaluation of oxidation resistance, especially for alloys which form oxides of low volatility. For alloys of higher chromium levels with high propensities toward forming a chromium-bearing scale of higher volatility, testing under conditions of high gas velocity is necessary to assess fully the behavior of the alloy.

  11. Modeling of ultrasonic propagation in heavy-walled centrifugally cast austenitic stainless steel based on EBSD analysis.

    PubMed

    Chen, Yao; Luo, Zhongbing; Zhou, Quan; Zou, Longjiang; Lin, Li

    2015-05-01

    The ultrasonic inspection of heavy-walled centrifugally cast austenitic stainless steel (CCASS) is challenging due to the complex metallurgical structure. Numerical modeling could provide quantitative information on ultrasonic propagation and plays an important role in developing advanced and reliable ultrasonic inspection techniques. But the fundamental obstacle is the accurate description of the complex metallurgical structure. To overcome this difficulty, a crystal orientation map of a CCASS specimen in the 96 mm × 12 mm radial-axial cross section was acquired based on the electron backscattered diffraction (EBSD) technique and it was used to describe the coarse-grained structure and grain orientation. A model of ultrasonic propagation for CCASS was built according to the EBSD map. The ultrasonic responses of the CCASS sample were also tested. Some experimental phenomena such as structural noise and signal distortion were reproduced. The simulated results showed a good consistence with the experiments. The modeling method is expected to be effective for the precise interpretation of ultrasonic propagation in the polycrystalline structures of CCASS. PMID:25670411

  12. 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.

  13. Femtosecond laser micromachining of polyvinylidene fluoride (PVDF) based piezo films

    NASA Astrophysics Data System (ADS)

    Lee, Seongkuk; Bordatchev, Evgueni V.; Zeman, Marco J. F.

    2008-04-01

    Piezoelectric polymers have been known to exist for more than 40 years, but in recent years they have been recognized as smart materials for the fabrication of microsensors, microactuators and other micro-electro-mechanical systems (MEMS). In this work, femtosecond laser micromachining of a polyvinylidene fluoride (PVDF) film, coated with NiCu on both sides, has been studied to understand selective patterning mechanisms of NiCu layers and ablation characteristics of PVDF films. A detailed characterization of morphological changes of the laser-irradiated areas has been investigated using scanning electron microscopy. Through morphological analysis, the multiple shot damage thresholds of a 28 µm thick PVDF film and 40 nm thick NiCu layer have been determined. Surface morphology examination indicates that NiCu layers are removed from the PVDF film through a sequence of cracking-peeling off-curling. In addition, the NiCu layer on the rear side was also removed by the partially transmitted laser energy. The PVDF film was removed in forms of bundles of filaments and solid fragments by a combination of pure ablation and explosive removal of material by bursting of bubbles; the role of the explosive removal becomes more dominant with the increase of laser fluence. Optimal process conditions for cutting of the PVDF film and patterning of the NiCu coating without damaging the PVDF polymer have been established and applied to fabricate a vibration microsensor prototype that shows significant potential in using PVDF-based functional microdevices for telecommunications, transportation and biomedical applications.

  14. Low Cycle Fatigue Behavior and Life Prediction of a Cast Cobalt-Based Superalloy

    NASA Astrophysics Data System (ADS)

    Yang, Ho-Young; Kim, Jae-Hoon; Yoo, Keun-Bong

    Co-base superalloys have been applied in the stationary components of gas turbine owing to their excellent high temperature properties. Low cycle fatigue data on ECY-768 reported in a companion paper were used to evaluate fatigue life prediction models. In this study, low cycle fatigue tests are performed as the variables of total strain range and temperatures. The relations between plastic and total strain energy densities and number of cycles to failure are examined in order to predict the low cycle fatigue life of Cobalt-based super alloy at different temperatures. The fatigue lives is evaluated using predicted by Coffin-Manson method and strain energy methods is compared with the measured fatigue lives at different temperatures. The microstructure observing was performed for how affect able to low-cycle fatigue life by increasing the temperature.

  15. Antibacterial activity against E. coli O157:H7, physical properties, and storage stability of novel carvacrol-containing edible tomato films.

    PubMed

    Du, W-X; Olsen, C W; Avena-Bustillos, R J; McHugh, T H; Levin, C E; Friedman, Mendel

    2008-09-01

    Edible films containing plant antimicrobials are gaining importance as potential treatment to extend product shelf life and reduce risk of pathogen growth on contaminated food surfaces. The main objective of the present study was to evaluate the antimicrobial activities, storage stabilities, and physical-chemical-mechanica1 properties of novel edible films made from tomatoes containing carvacrol, the main constituent of oregano oil. The antimicrobial activities against E. coli O157:H7 and the stability of carvacrol were evaluated during the preparation and storage of tomato-based films made by 2 different casting methods, continuous casting and batch casting. Antimicrobial assays of tomato films indicated that optimum antimicrobial effects occurred with carvacrol levels of approximately 0.75% added to tomato purees before film preparation. HPLC analysis of the films indicated that the carvacrol concentrations and bactericidal effect of the films remained unchanged over the storage period of up to 98 d at 5 and 25 degrees C. Carvacrol addition to the tomato puree used to prepare the films increased water vapor permeability of tomato films. The continuous method for casting of the films appears more suitable for large-scale use than the batch method. This 1st report on tomato-based edible antimicrobial tomato films suggests that these films have the potential to prevent adverse effects of contaminated food and promote human health associated with the consumption of tomatoes. PMID:18803723

  16. 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

  17. Bacteria counting method based on polyaniline/bacteria thin film.

    PubMed

    Zhihua, Li; Xuetao, Hu; Jiyong, Shi; Xiaobo, Zou; Xiaowei, Huang; Xucheng, Zhou; Tahir, Haroon Elrasheid; Holmes, Mel; Povey, Malcolm

    2016-07-15

    A simple and rapid bacteria counting method based on polyaniline (PANI)/bacteria thin film was proposed. Since the negative effects of immobilized bacteria on the deposition of PANI on glass carbon electrode (GCE), PANI/bacteria thin films containing decreased amount of PANI would be obtained when increasing the bacteria concentration. The prepared PANI/bacteria film was characterized with cyclic voltammetry (CV) technique to provide quantitative index for the determination of the bacteria count, and electrochemical impedance spectroscopy (EIS) was also performed to further investigate the difference in the PANI/bacteria films. Good linear relationship of the peak currents of the CVs and the log total count of bacteria (Bacillus subtilis) could be established using the equation Y=-30.413X+272.560 (R(2)=0.982) over the range of 5.3×10(4) to 5.3×10(8)CFUmL(-1), which also showed acceptable stability, reproducibility and switchable ability. The proposed method was feasible for simple and rapid counting of bacteria. PMID:26921555

  18. Films and components from holographic recording based on bacteriorhodopsin

    NASA Astrophysics Data System (ADS)

    Hampp, Norbert A.; Sanio, Markus; Anderle, Klaus

    2000-03-01

    Since more than ten years films and cubes made from the halobacterial photochromic retinal protein bacteriorhodopsin (BR) are discussed as storage media for short-term and long- term data storage. The efficient photochemistry of BR, the stability towards chemical and thermal degradation, the reversibility and the polarization recording capability of bacteriorhodopsin films are attractive. The limited storage time of the recorded information implies some restrictions in the use of this material. Because bacteriorhodopsin returns also through a thermal pathway to its initial state recorded information decays with a characteristic time constant which is related to the lifetime of the M-state of the material. By genetic methods and by suitable film compositions this value can be extended up to several minutes which is more than enough for all real-time applications. In some cases a longer storage time is desired, among them optical data storage. Optical modules and components based on bacteriorhodopsin films, which can be thermostated to different temperatures, are presented. They allow very sensitive optical recording and can be photochemically or thermally erased. These bacteriorhodopsin containing modules may be used for high resolution optical recording with extended storage time.

  19. Immunosensor systems with the Langmuir-film-based fluorescence detection

    SciTech Connect

    Chudinova, G K; Nagovitsyn, I A; Savranskii, V V; Karpov, R E

    2003-09-30

    A method is developed for detecting protein antigens for fluorescent immunoassay using a model system based on the technique for preparation of Langmuir films. Fluorescein isothiocyanate and donor-acceptor energy-transfer pairs of markers (the Yb complex of tetraphenyl porphyrin - benzoyl trifluoroacetoneisothiocyanate and derivatives of tetra(carboxyphenyl) porphyrin - cyanine dye containing a five-membered polyene chain), which were nor studied earlier, were used as markers for detecting the binding of an antigen on the surface of Langmuir films of antibodies. Fluorescence was detected in the near-IR region (for the first pair) and in the visible spectral range (for the second pair). To reduce the nonspecific sorption of a protein (antigen), a method was proposed for the preparation of a nonpolar surface by applying an even number of layers of stearic acid as a substrate for the Langmuir - Blodgett film. A high sensitivity of model systems to a protein antigen in solution was achieved ({approx}10{sup -11} M), the assay time being 6 - 8 min. The model system with the first donor - acceptor pair was tested in analysis of the blood plasma. The fluorescence of the Dy{sup 3+}, Tm{sup 3+}, and Yb{sup 3+} complexes of tetraphenyl porphyrin sensitised by diketonate complexes of lanthanides was studied for the first time and the enhancement of the IR fluorescence of these complexes in a Langmuir film was demonstrated. (papers devoted to the memory of academician a m prokhorov)

  20. Quantification of ecotoxicological tests based on bioluminescence using Polaroid film.

    PubMed

    Tamminen, Manu V; Virta, Marko P J

    2007-01-01

    Assays based on the measurement of bacterial luminescence are widely used in ecotoxicology. Bacterial strains responding either to general toxicity or specific pollutants are rapid, cost-effective and easy to use. However, quantification of the signal requires relatively expensive instrumentation. We show here that the detection of luminescence of BioTox, a Vibrio fischeri-based toxicity test, and of a specific recombinant bacterial strain for arsenic determination, is possible using common Polaroid film. The exposed films can be used for visual or computer-assisted quantification of the signal. Qualitative visual comparison to standards can be used in the rapid and relatively accurate estimation of toxicity or pollutant concentration. The computer-assisted method significantly improves the accuracy and quantification of the results. The results obtained by computer-assisted quantification were in good agreement with the values obtained with a luminometer. PMID:16949132

  1. Superconducting thin film cavities and base electrode planarization

    NASA Astrophysics Data System (ADS)

    Thomas, Christopher Doyle

    1997-11-01

    This study concerns two separate projects. The first deals with a new technique to improve superconducting tunnel junction fabrication technology through the use of planarized base electrodes. Planarization, resulting in smooth film surfaces, is realized by coating a conventional niobium base electrode with a multilayer of niobium and aluminum. Very low leakage tunnel junctions were made using this method. The second project involves electromagnetic coupling to a superconducting thin film cavity. A novel device, potentially useful as an x-ray detector, has been fabricated and characterized. The theory of operation of this closed superconducting cavity, or "Fiske Cavity", is presented along with experimental results. Current - voltage measurements reveal current steps at selected voltages that are predicted theoretically and indicate electromagnetic coupling in this system. This form of coupling motivates new devices with arrays of phase locked junctions that interact through an underlying resonant waveguide and with no external microwave source.

  2. Preparation and properties of films cast from mixtures of poly(vinyl alcohol) and submicron particles prepared from amylose-palmitic acid inclusion complexes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The use of starch in polymer composites for film production has been studied extensively for increasing biodegradability, improving film properties and reducing cost. Starch nanoparticles have received much attention, primarily those obtained by acid hydrolysis of starch granules. In this study, nan...

  3. 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.

  4. Fatigue Properties of Cast Magnesium Wheels

    NASA Astrophysics Data System (ADS)

    Li, Zhenming; Luo, Alan A.; Wang, Qigui; Peng, Liming; Zhang, Peng

    2016-05-01

    This paper investigates the fatigue properties and deformation behavior of a newly developed Mg-2.96Nd-0.21Zn-0.39Zr magnesium alloy wheel in both as-cast and T6 conditions. Compared with the as-cast alloy, the T6-treated alloy shows a significant increase in fatigue strength and cyclic stress amplitude. This is believed to be attributed to the change of defect type from porosity to oxides and the increased matrix strength in the T6 (peak-aged) condition. For the as-cast alloy wheel, fatigue failure mainly originated from the cast defects including porosity, oxide film, and inclusion at or near the sample surface. In the T6-treated alloy, however, oxides and inclusions or slip bands initiate the fatigue cracks. Solution treatment appears to reduce or eliminate the shrinkage porosity because of grain growth and dissolution of as-cast eutectic phases in the grain boundaries. The cyclic stress amplitude of the as-cast alloy increases with increasing the number of cycles, while the T6-treated alloy shows cyclic softening after the stress reaches a maximum value. The Coffin-Manson law and Basquin equation can be used to evaluate the life of low cycle fatigue. The developed long crack model and multi-scale fatigue (MSF) models can be used to predict high-cycle fatigue life of the Mg-2.96Nd-0.21Zn-0.39Zr alloys with or without casting defects.

  5. Fatigue Properties of Cast Magnesium Wheels

    NASA Astrophysics Data System (ADS)

    Li, Zhenming; Luo, Alan A.; Wang, Qigui; Peng, Liming; Zhang, Peng

    2016-08-01

    This paper investigates the fatigue properties and deformation behavior of a newly developed Mg-2.96Nd-0.21Zn-0.39Zr magnesium alloy wheel in both as-cast and T6 conditions. Compared with the as-cast alloy, the T6-treated alloy shows a significant increase in fatigue strength and cyclic stress amplitude. This is believed to be attributed to the change of defect type from porosity to oxides and the increased matrix strength in the T6 (peak-aged) condition. For the as-cast alloy wheel, fatigue failure mainly originated from the cast defects including porosity, oxide film, and inclusion at or near the sample surface. In the T6-treated alloy, however, oxides and inclusions or slip bands initiate the fatigue cracks. Solution treatment appears to reduce or eliminate the shrinkage porosity because of grain growth and dissolution of as-cast eutectic phases in the grain boundaries. The cyclic stress amplitude of the as-cast alloy increases with increasing the number of cycles, while the T6-treated alloy shows cyclic softening after the stress reaches a maximum value. The Coffin-Manson law and Basquin equation can be used to evaluate the life of low cycle fatigue. The developed long crack model and multi-scale fatigue (MSF) models can be used to predict high-cycle fatigue life of the Mg-2.96Nd-0.21Zn-0.39Zr alloys with or without casting defects.

  6. 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.

  7. Preparation and Properties of Silver Nanowire-Based Transparent Conductive Composite Films

    NASA Astrophysics Data System (ADS)

    Tian, Ji-Li; Zhang, Hua-Yu; Wang, Hai-Jun

    2016-06-01

    Silver nanowire-based transparent conductive composite films with different structures were successfully prepared using various methods, including liquid polyol, magnetron sputtering and spin coating. The experimental results revealed that the optical transmittance of all different structural composite films decreased slightly (1-3%) compared to pure films. However, the electrical conductivity of all composite films had a great improvement. Under the condition that the optical transmittance was greater than 78% over the wavelength range of 400-800 nm, the AgNW/PVA/AgNW film became a conductor, while the AZO/AgNW/AZO film and the ITO/AgNW/ITO film showed 88.9% and 94% reductions, respectively, for the sheet resistance compared with pure films. In addition, applying a suitable mechanical pressure can improve the conductivity of AgNW-based composite films.

  8. Hydrogen Microsensor Based on NiO Thin Films

    NASA Astrophysics Data System (ADS)

    Fasaki, I.; Antoniadou, M.; Giannoudakos, A.; Stamataki, M.; Kompitsas, M.; Roubani-Kalantzopoulou, F.; Hotovy, I.; Rehacek, V.

    A multitude of industries use H2 either as part of their process or as a fuel. All these applications motivate nowadays the development of hydrogen sensor devices which enable its safe and controlled use. Since H2 is explosive above the lower explosion limit at 40,000 ppm, devices which permit the detection of its presence and measure its concentration become indispensable. In this work, we present a microsensor based on NiO thin films produced with dc reactive magnetron sputtering on GaAs, with an incorporated Pt heater, all on a DO-8 package ready for use. The microsensor was tested to H2 concentrations 5,000 and 10,000 ppm at different working temperatures. The change of the electrical resistance of NiO thin films was the signal for hydrogen sensing. The response of the sensor was not proportional to concentration of the gas neither to the working temperature.

  9. 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 μm of static displacement, with 80–90 μm displacements being typical, using four 920 μm long by 70 μm 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

  10. 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.

  11. Dendritic wideband metamaterial absorber based on resistance film

    NASA Astrophysics Data System (ADS)

    Wang, Bing; Gong, Bo Yi; Wang, Mei; Weng, Bin; Zhao, Xiaopeng

    2015-03-01

    A type of dendritic wideband metamaterial absorber was designed and constructed from resistance film composed of indium-tin oxide conductive film having a dendritic metamaterial structure, dielectric layer made of polymethacrylimide foam, and metallic sheet based on the equivalent circuit model. In terms of normal incidence, the simulation using the absorber yielded operating absorption rates >80 % in the frequency range of 8-27.9 GHz. In addition, the experimental measurements verified 8-17 GHz range of more than 80 % absorption rate, whereas its relative bandwidth reached 72 %. Moreover, this reasonable absorption performance was maintained for oblique incidences of <60°. The effects of dielectric layer thickness on absorption properties were verified.

  12. Cast iron (CI) based soft magnetic BMG Ci88.3Al2Ga1P4.35B4.35

    NASA Astrophysics Data System (ADS)

    Kane, S. N.; Lee, H. J.; Jeong, Y. H.; Varga, L. K.

    2009-01-01

    Thermal stability, structure, and magnetic properties of bulk type Ci88.3Al2Ga1P4.35B4.35 alloy in ribbon form have been studied using differential thermal analysis, x-ray diffraction and magnetic measurements. Results reveal that crystallization peak temperature (Tx) and Curie temperature (Tc) of the as-cast alloy are respectively 513 and 370 °C. Crystallization of the specimen starts after annealing at 460 °C and α-Fe is precipitated out. Annealing at temperatures higher than 515 °C, produces apart from α-Fe, hard magnetic precipitants (Fe2B, Fe3B), which deteriorate the soft magnetic properties. Lowest coercive field - 9.8 A/m, highest saturation of induction - 1.55 Tesla and best losses - 0.42 W/kg (at 50 Hz and 0.4 kA/m) were obtained for as-cast specimen. Observed good soft magnetic properties of these low cost cast-iron based alloys suggest perspective applications of these soft magnetic alloys as an alternative to the conventional Fe-Si electrical steel and Mn-Zn ferrites.

  13. 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; Truhan, Jr., John J; Kenik, Edward A

    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.

  14. Cool Cast Facts

    MedlinePlus

    ... outer layer is usually made of plaster or fiberglass. Fiberglass casts are made of fiberglass, which is a plastic that can be shaped. Fiberglass casts come in many different colors — if you' ...

  15. 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

  16. 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

  17. An Easily Accessible Self-Healing Transparent Film Based on a 2D Supramolecular Network of Hydrogen-Bonding Interactions between Polymeric Chains.

    PubMed

    Roy, Nabarun; Tomović, Željko; Buhler, Eric; Lehn, Jean-Marie

    2016-09-12

    Self-healing polymers hold great promise for the future, enhancing in particular the longevity of polymeric materials. We describe a self-healing covalent polymer, presenting an extensive array of hydrogen-bonding sites based on the combination of urea, urethane, and bis-acyl-hydrazine units. Solvent-cast thin-films prepared by polycondensation of a commercially available dihydrazide and a diisocyanate prepolymer exhibited excellent room temperature autonomous healing with almost full recovery of mechanical properties when two parts of a cut film were overlapped and gently pressed together. This autonomous healing upon damage may be attributed to the supramolecular dynamics of multiple lateral inter-chain hydrogen-bonding interactions between the polymer chains. The solid-state structure of a model compound incorporating the same structural backbone corroborates the existence of an extensive two-dimensional supramolecular hydrogen-bonding network. PMID:27226034

  18. LLNL casting technology

    SciTech Connect

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

    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.

  19. LLNL casting technology

    NASA Astrophysics Data System (ADS)

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

    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 competiveness 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.

  20. 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

  1. Bismuth pyrochlore-based thin films for dielectric energy storage

    NASA Astrophysics Data System (ADS)

    Michael, Elizabeth K.

    The drive towards the miniaturization of electronic devices has created a need for dielectric materials with large energy storage densities. These materials, which are used in capacitors, are a critical component in many electrical systems. Here, the development of dielectric energy storage materials for pulsed power applications, which require materials with the ability to accumulate a large amount of energy and then deliver it to the system rapidly, is explored. The amount of electrostatic energy that can be stored by a material is a function of the induced polarization and the dielectric breakdown strength of the material. An ideal energy storage dielectric would possess a high relative permittivity, high dielectric breakdown strength, and low loss tangent under high applied electric fields. The bismuth pyrochlores are a compositionally tunable family of materials that meet these requirements. Thin films of cubic pyrochlore bismuth zinc niobate, bismuth zinc tantalate, and bismuth zinc niobate tantalate, were fabricated using a novel solution chemistry based upon the Pechini method. This solution preparation is advantageous because it avoids the use of teratogenic solvents, such as 2-methoxyethanol. Crystalline films fabricated using this solution chemistry had very small grains that were approximately 27 nm in lateral size and 35 nm through the film thickness. Impedance measurements found that the resistivity of the grain boundaries was two orders of magnitude higher than the resistivity of the grain interior. The presence of many resistive grain boundaries impeded conduction through the films, resulting in high breakdown strengths for these materials. In addition to high breakdown strengths, this family of materials exhibited moderate relative permittivities of between 55 +/- 2 and 145 +/- 5, for bismuth zinc tantalate and bismuth zinc niobate, respectively, and low loss tangents on the order of 0.0008 +/- 0.0001. Increases in the concentration of the tantalum

  2. Prediction of Optimum Combination of Eudragit RS/Eudragit RL/Ethyl Cellulose Polymeric Free Films Based on Experimental Design for Using as a Coating System for Sustained Release Theophylline Pellets

    PubMed Central

    Akhgari, Abbas; Tavakol, Ali

    2016-01-01

    Purpose: The physicochemical properties of free films made from different mixtures of sustained release polymers were investigated, and an optimum formulation coating on drug containing pellets, based on the study of free film was evaluated. Methods: In order to determine the effect of different variables on the permeability and swelling of films and procedure optimization, the experimental design was fulfilled based on the statistical method of a 33 full factorial design, and according to this method 27 formulations were prepared. The films were prepared using casting-solvent evaporation method. Water vapor permeability, the swelling and permeability of free films in both acidic and buffer media, were carried out. Then, the pellets containing theophylline were coated with the optimum formulation. Results: The results of this study demonstrated that an increase in the free film thickness and Eurdragit RS ratio in films lowered the water vapor transmission (WVT), the swelling and the permeability of all formulations, while an increase in the quantity of ethylcellulose, up to a specific ratio (approximately 40%), decreased the permeability and swelling. The most optimum free film formulation was made up of 60% Eudragit RS and 40% ethylcellulose. Conclusion: Pellets coated with a 10% coating level of ethylcellulose and Eudragit RS (4:6) showed suitable release properties and could serve as a favorable sustained release system for theophylline. PMID:27478784

  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

  4. 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

  5. Enhanced optical discrimination system based on switchable retroreflective films

    NASA Astrophysics Data System (ADS)

    Schultz, Phillip; Heikenfeld, Jason

    2016-04-01

    Reported herein is the design, characterization, and demonstration of a laser interrogation and response optical discrimination system based on large-area corner-cube retroreflective films. The switchable retroreflective films use light-scattering liquid crystal to modulate retroreflected intensity. The system can operate with multiple wavelengths (visible to infrared) and includes variable divergence optics for irradiance adjustments and ease of system alignment. The electronic receiver and switchable retroreflector offer low-power operation (<4 mW standby) on coin cell batteries with rapid interrogation to retroreflected signal reception response times (<15 ms). The entire switchable retroreflector film is <1 mm thick and is flexible for optimal placement and increased angular response. The system was demonstrated in high ambient lighting conditions (daylight, 18k lux) with a visible 10-mW output 635-nm source out to a distance of 400 m (naked eye detection). Nighttime demonstrations were performed using a 1.5-mW, 850-nm infrared laser diode out to a distance of 400 m using a night vision camera. This system could have tagging and conspicuity applications in commercial or military settings.

  6. Thin-film transistors based on organic conjugated semiconductors

    NASA Astrophysics Data System (ADS)

    Garnier, Francis

    1998-02-01

    The use of organic semiconductors as active layers in thin-film transistors has raised in the recent years a large interest, both for the fundamental understanding of the charge transport processes in organic materials, and also for the potential applications of these devices in the new field of flexible electronics. Short conjugated oligomers have been shown to possess much higher field-effect mobilities than their parent conjugated polymers. The origin of such increase in the efficiency of charge transport is mainly attributed to the close-packing and long-range structural organization displayed in thin films of conjugated oligomers. The various routes for controlling this organization are described, which allow to realize liquid crystal-like two-dimensional structures for these semiconductors, whose carrier mobility has now become equivalent to that of amorphous silicon. It is also shown that the effect of conjugation length on carrier mobility is not as critical as previously thought, but the associated increase of the band gap energy effects the efficiency of charge injection at the metal/semiconductor interface. This problem can be answered by realizing a local doping of the semiconductor, which allows the injection of charge to operate through an efficient tunneling mechanism. Organic-based thin-film transistors have now become viable devices.

  7. A biomimetic tactile sensing system based on polyvinylidene fluoride film.

    PubMed

    Xin, Yi; Tian, Hongying; Guo, Chao; Li, Xiang; Sun, Hongshuai; Wang, Peiyuan; Qian, Chenghui; Wang, Shuhong; Wang, Cheng

    2016-02-01

    Polyvinylidene fluoride (PVDF) film has been widely investigated as a sensing material due to its outstanding properties such as biocompatibility, high thermal stability, good chemical resistance, high piezo-, pyro- and ferro-electric properties. This paper reports on the design, test, and analysis of a biomimetic tactile sensor based on PVDF film. This sensor consists of a PVDF film with aluminum electrodes, a pair of insulating layers, and a "handprint" friction layer with a copper foil. It is designed for easy fabrication and high reliability in outputting signals. In bionics, the fingerprint of the glabrous skin plays an important role during object handling. Therefore, in order to enhance friction and to provide better manipulation, the ridges of the fingertips were introduced into the design of the proposed tactile sensor. And, a basic experimental study on the selection of the high sensitivity fingerprint type for the biomimetic sensor was performed. In addition, we proposed a texture distinguish experiment to verify the sensor sensitivity. The experiment's results show that the novel biomimetic sensor is effective in discriminating object surface characteristics. Furthermore, an efficient visual application program (LabVIEW) and a quantitative evaluation method were proposed for the verification of the biomimetic sensor. The proposed tactile sensor shows great potential for contact force and slip measurements. PMID:26931883

  8. A biomimetic tactile sensing system based on polyvinylidene fluoride film

    NASA Astrophysics Data System (ADS)

    Xin, Yi; Tian, Hongying; Guo, Chao; Li, Xiang; Sun, Hongshuai; Wang, Peiyuan; Qian, Chenghui; Wang, Shuhong; Wang, Cheng

    2016-02-01

    Polyvinylidene fluoride (PVDF) film has been widely investigated as a sensing material due to its outstanding properties such as biocompatibility, high thermal stability, good chemical resistance, high piezo-, pyro- and ferro-electric properties. This paper reports on the design, test, and analysis of a biomimetic tactile sensor based on PVDF film. This sensor consists of a PVDF film with aluminum electrodes, a pair of insulating layers, and a "handprint" friction layer with a copper foil. It is designed for easy fabrication and high reliability in outputting signals. In bionics, the fingerprint of the glabrous skin plays an important role during object handling. Therefore, in order to enhance friction and to provide better manipulation, the ridges of the fingertips were introduced into the design of the proposed tactile sensor. And, a basic experimental study on the selection of the high sensitivity fingerprint type for the biomimetic sensor was performed. In addition, we proposed a texture distinguish experiment to verify the sensor sensitivity. The experiment's results show that the novel biomimetic sensor is effective in discriminating object surface characteristics. Furthermore, an efficient visual application program (LabVIEW) and a quantitative evaluation method were proposed for the verification of the biomimetic sensor. The proposed tactile sensor shows great potential for contact force and slip measurements.

  9. Engineered pigments based on iridescent cellulose nanocrystal films.

    PubMed

    Bardet, Raphael; Roussel, Francine; Coindeau, Stéphane; Belgacem, Naceur; Bras, Julien

    2015-05-20

    A simple method to produce biobased iridescent pigments from cellulose nanocrystal (CNC) films is reported. The process consists of forming nanostructured films from a CNC liquid-crystalline suspension and an appropriate dry grinding. The features of the iridescent pigments are described; they have a flake-like morphology with a thickness of 25 μm. However, because of the presence of sulfate groups, thermal degradation and high redispersion in water occur, which affect the iridescent property of these biobased pigments. To overcome such limitations, two post-treatments are proposed. The sulfate ester groups are removed from the iridescent pigments with vacuum overdrying. The mass loss of iridescent pigment in water is reduced with an increase of the ionic strength in the aqueous medium by NaCl addition. These post-treatments have proven to be efficient and engineered pigments based on CNC films can be used to add anticounterfeiting features to packaging manufactured by classical paper techniques or extrusion. PMID:25817681

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

    NASA Astrophysics Data System (ADS)

    Muratov, C. B.; Osipov, V. V.

    2006-08-01

    Thin film micromagnetics are a broad class of materials with many technological applications, primarily in magnetic memory. The dynamics of the magnetization distribution in these materials is traditionally modeled by the Landau-Lifshitz-Gilbert (LLG) equation. Numerical simulations of the LLG equation are complicated by the need to compute the stray field due to the inhomogeneities in the magnetization which presents the chief bottleneck for the simulation speed. Here, we introduce a new method for computing the stray field in a sample for a reduced model of ultra-thin film micromagnetics. The method uses a recently proposed idea of optimal finite difference grids for approximating Neumann-to-Dirichlet maps and has an advantage of being able to use non-uniform discretization in the film plane, as well as an efficient way of dealing with the boundary conditions at infinity for the stray field. We present several examples of the method's implementation and give a detailed comparison of its performance for studying domain wall structures compared to the conventional FFT-based methods.

  11. Tantalum-based thin film coatings for wear resistant arthroprostheses.

    PubMed

    Balagna, C; Faga, M G; Spriano, S

    2011-10-01

    Cobalt-chromium-molybdenum alloys with high carbon content (HC-CoCrMo) are widely used as materials for arthroprosthesis, in particular in metal-on-metal (MoM) hip joints. In spite of their good wear and corrosion resistance, production of metallic wear particles and metal ion release will occur on a large time-scale. An enhancement of the metal ion level in the patient's blood and urine is often reported in clinical data. Hypersensitivity, inflammatory response and cell necrosis can occur as consequence. So implants on young patients and women on childbearing age are not so widespread. The aim of this research is the realization of a thin film coating in order to improve the biocompatibility of Co-based alloys and to reduce debris production, ion release and citotoxicity. The innovative process consists of a thermal treatment in molten salts, in order to obtain a tantalum enriched thin film coating. Tantalum is chosen because it is considered a biocompatible metal with high corrosion resistance and low ion release. Three HC-CoCrMo alloys, produced by different manufacturing processes, are tested as substrates. The coating is a thin film of TaC or it can be composed by a multilayer of two tantalum carbides and metallic tantalum, depending on the temperature of the treatment and on the carbon content of the substrate. The thin films as well the substrates are characterized from the structural, chemical and morphological point of view. Moreover mechanical behaviour of treated and untreated materials is analyzed by means of nanohardness, scratch and ball-on-disc wear tests. The coating increases the mechanical and tribological properties of HC-CoCrMo. PMID:22400292

  12. 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.; 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.

  13. Slip Casting of α-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, α-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.

  14. Functional properties and antifungal activity of films based on gliadins containing cinnamaldehyde and natamycin.

    PubMed

    Balaguer, Mari Pau; Fajardo, Paula; Gartner, Hunter; Gomez-Estaca, Joaquin; Gavara, Rafael; Almenar, Eva; Hernandez-Munoz, Pilar

    2014-03-01

    Gliadin films cross-linked with cinnamaldehyde (1.5, 3, and 5%) and incorporated with natamycin (0.5%) were prepared by casting, and their antifungal activity, water resistance, and barrier properties were characterized. Incorporation of natamycin gave rise to films with greater water uptake, weight loss and diameter gain, and higher water vapor and oxygen permeabilities. These results may be associated to a looser packing of the protein chains as a consequence of the presence of natamycin. The different cross-linking degree of the matrices influenced the natamycin migration to the agar test media, increasing from 13.3 to 23.7 (μg/g of film) as the percentage of cinnamaldehyde was reduced from 5% to 1.5%. Antifungal activity of films was assayed against common food spoilage fungi (Penicillium species, Alternaria solani, Colletotrichum acutatum). The greatest effectiveness was obtained for films containing natamycin and treated with 5% of cinnamaldehyde. The level of cinnamaldehyde reached in the head-space of the test assay showed a diminishing trend as a function of time, which was in agreement with fungal growth and cinnamaldehyde metabolization. Developed active films were used in the packaging of cheese slices showing promising results for their application in active packaging against food spoilage. PMID:24412960

  15. Edible films based on cassava starch and fructooligosaccharides produced by Bacillus subtilis natto CCT 7712.

    PubMed

    Bersaneti, Gabrielly Terassi; Mantovan, Janaina; Magri, Agnes; Mali, Suzana; Celligoi, Maria Antonia Pedrine Colabone

    2016-10-20

    The objectives of this work were to produce fructooligosaccharides (FOSs) by using the microorganism Bacillus subtilis natto CCT 7712 and to employ these FOSs as a functional ingredient in cassava starch edible films, which were characterized according to their microstructure, mechanical and barrier properties. The produced FOSs could be easily dissolved, resulting in homogeneous filmogenic solutions, which were easily manipulated to obtain films by casting. FOSs were added in different concentrations (0, 1, 5 and 10g/100g solids), and glycerol was used as a plasticizer (20g/100g solids). All formulations resulted in films that had a good appearance and were easily removable from the plates without bubbles or cracks. The FOSs exerted a plasticizing effect on the starch films and decreased their glass transition temperature. The addition of FOSs resulted in higher solubility and elongation and a decreased water vapor permeability of the films. FOSs were shown to be a promising ingredient for use in edible starch films. PMID:27474664

  16. Towards cost-effective, solution processed, encapsulant films for organic electronic devices -- controlling flow instabilities during film formation

    NASA Astrophysics Data System (ADS)

    Granstrom, Jimmy; Roy, Anshuman; Rowell, Griffin; Moon, Ji Sun; Jerkunica, Evan; Heeger, Alan

    2010-03-01

    We present a general method for making thin and smooth films of a water-repelling perfluorinated polymer. These films function as encapsulation barrier layers against water and oxygen permeation. Based on a phenomenological analysis, we find that disturbances in flow due to the Rayleigh-Benard-Marangoni instability during drying of spin-cast perfluorinated polymer films cause high surface roughness and the formation of ``pinholes.'' Atomic Force Microscopy measurements show that this instability can increase the surface roughness by an order of magnitude. Casting films from solutions with higher polymer concentration and from solvents with higher viscosity suppress the instability and significantly reduce the roughness. Suppression of the instability results in improved barrier properties as indicated by the calcium thin film optical transmission test.

  17. Photopolymerization-based fabrication of chemical sensing films

    DOEpatents

    Yang, Xiaoguang; Swanson, Basil I.; Du, Xian-Xian

    2003-12-30

    A photopolymerization method is disclosed for attaching a chemical microsensor film to an oxide surface including the steps of pretreating the oxide surface to form a functionalized surface, coating the functionalized surface with a prepolymer solution, and polymerizing the prepolymer solution with ultraviolet light to form the chemical microsensor film. The method also allows the formation of molecular imprinted films by photopolymerization. Formation of multilayer sensing films and patterned films is allowed by the use of photomasking techniques to allow patterning of multiple regions of a selected sensing film, or creating a sensor surface containing several films designed to detect different compounds.

  18. Investigation on the Interface Characteristics of Al/Mg Bimetallic Castings Processed by Lost Foam Casting

    NASA Astrophysics Data System (ADS)

    Jiang, Wenming; Li, Guangyu; Fan, Zitian; Wang, Long; Liu, Fuchu

    2016-05-01

    The lost foam casting (LFC) process was used to prepare the A356 aluminum and AZ91D magnesium bimetallic castings, and the interface characteristics of the reaction layer between aluminum and magnesium obtained by the LFC process were investigated in the present work. The results indicate that a uniform and compact interface between the aluminum and magnesium was formed. The reaction layer of the interface with an average thickness of approximately 1000 μm was mainly composed of Al3Mg2 and Al12Mg17 intermetallic compounds, including the Al3Mg2 layer adjacent to the aluminum insert, the Al12Mg17 middle layer, and the Al12Mg17 + δ eutectic layer adjacent to the magnesium base. Meanwhile, the Mg2Si intermetallic compound was also detected in the reaction layer. An oxide film mainly containing C, O, and Mg elements generated at the interface between the aluminum and magnesium, due to the decomposed residue of the foam pattern, the oxidations of magnesium and aluminum alloys as well as the reaction between the magnesium melt and the aluminum insert. The microhardness tests show that the microhardnesses at the interface were obviously higher than those of the magnesium and aluminum base metals, and the Al3Mg2 layer at the interface had a high microhardness compared with the Al12Mg17 and Al12Mg17 + δ eutectic layers, especially the eutectic layer.

  19. Optical switch based on nanocrystalline VOx thin film

    NASA Astrophysics Data System (ADS)

    Chen, Xiqu; Dai, Jun

    2009-11-01

    An optical switch is fabricated based on nanocrystalline vanadium oxide (VOx) thin film using micromachining technology. An "on" state with semiconducting phase to an "off" state with metallic phase is controlled by applying a DC power to Aurum electrodes of the optical switch. The optical switching performance for the fabricated device is investigated at optical communication wavelength of 1.55μm. The heater power requires to achieve switching action is about 15mW. The testing results show that the extinction ratio and switching response time are 14dB and 2ms, respectively.

  20. 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%.

  1. Advances in aluminum casting technology

    SciTech Connect

    Tiryakioglu, M.; Campbell, J.

    1998-01-01

    This symposium focuses on the improvements of aluminum casting quality and reliability through a better understanding of processes and process variables, and explores the latest innovations in casting-process design that allow increasing use of the castings to replace complex assemblies and heavy steel and cast-iron components in aerospace and automotive applications. Presented are 35 papers by international experts in the various aspects of the subject. The contents include: Semisolid casting; Computer-aided designing of molds and castings; Casting-process modeling; Aluminum-matrix composite castings; HIPing of castings; Progress in the US car project; Die casting and die design; and Solidification and properties.

  2. Radiative recombination kinetics in electroluminescent spin cast pristine α-4T

    NASA Astrophysics Data System (ADS)

    Ben Hamed, Zied; Kouki, Fayçal; Bouchriha, Habib; Mejatty, Mohamed

    2016-09-01

    Many experimental studies have established the substantial impact of the sound structure of the organic thin films on optoelectronic device performances. This study is a collection of experimental and theoretical investigation of the radiative recombination kinetics in an organic light emitting diode based on spin cast α-4T. The structural properties of the organic thin films (α-4T) deposited by the spin coating technique are discussed. The electrical characterization of the diode-like samples (ITO/α-4T/Al) have revealed a very low effective mobility of charge carriers in the spin cast α-4Tand the radiative recombination current was extracted. The luminescence-current characterization of the diode-like samples (ITO/α-4T/Al) was investigated and modeled.

  3. Evolution of nano-rheological properties of Nafion¯ thin films during pH modification by strong base treatment: A static and dynamic force spectroscopy study

    NASA Astrophysics Data System (ADS)

    Eslami, Babak; López-Guerra, Enrique A.; Raftari, Maryam; Solares, Santiago D.

    2016-04-01

    Addition of a strong base to Nafion® proton exchange membranes is a common practice in industry to increase their overall performance in fuel cells. Here, we investigate the evolution of the nano-rheological properties of Nafion thin films as a function of the casting pH, via characterization with static and dynamic, contact and intermittent-contact atomic force microscopy (AFM) techniques. The addition of KOH causes non-monotonic changes in the viscoelastic properties of the films, which behave as highly dissipative, softer materials near neutral pH values, and as harder, more elastic materials at extreme pH values. We quantify this behavior through calculation of the temporal evolution of the compliance and the glassy compliance under static AFM measurements. We complement these observations with dynamic AFM metrics, including dissipated power and virial (for intermittent-contact-mode measurements), and contact resonance frequency and quality factor (for dynamic contact-mode measurements). We explain the non-monotonic material property behavior in terms of the degree of ionic crosslinking and moisture content of the films, which vary with the addition of KOH. This work focuses on the special case study of the addition of strong bases, but the observed mechanical property changes are broadly related to water plasticizing effects and ionic crosslinking, which are also important in other types of films.

  4. Cooling Performance and Structural Reliability of a Modified Corrugated-insert Air-cooled Turbine Blade with an Integrally Cast Shell and Base

    NASA Technical Reports Server (NTRS)

    Freche, John C; Schum, Eugene F

    1957-01-01

    A modified corrugated-insert blade with integrally cast shell and base was developed. This blade was as light as a conventional fabricated corrugated-insert blade. Of four test blades operated in a full-scale turbojet engine, one failed after about 15 hours operation at an inlet gas temperature of 1670 degrees F, a coolant-flow ratio of 0.0064, and a 1/3-span centrifugal stress of approximately 28,000 psi. Three other test blades ran for approximately 16, 31, and 36 hours without failure at similar conditions.

  5. 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.

  6. 36 CFR 1237.30 - How do agencies manage records on nitrocellulose-base and cellulose-acetate base film?

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Department of Transportation regulations (49 CFR 172.101, Hazardous materials table; 172.504, Transportation... on nitrocellulose-base and cellulose-acetate base film? 1237.30 Section 1237.30 Parks, Forests, and... cellulose-acetate base film? (a) The nitrocellulose base, a substance akin to gun cotton, is...

  7. PET based nanocomposite films for microwave packaging applications

    NASA Astrophysics Data System (ADS)

    Galdi, M. R.; Olivieri, R.; Liguori, L.; Albanese, D.; Di Matteo, M.; Di Maio, L.

    2015-12-01

    In recent years, changes in life standards have promoted the diffusion of Ready to Cook (RTC) and Ready to Eat (RTE) products for microwave ovens. However, the main limits in microwave (MW) ovens usage are often related to the proper choice of packaging materials suitable for such technology. In fact, packages for microwaveable RTC and RTE foods should ensure adequate preservation of the product before cooking/heating such as high barriers to gases and aromas and adequate control of water vapor transmission. In addition, microwaveable packaging material must be transparent to MW, thermally stable and resistant to the mechanical stress induced by the accumulation in the head space of volatile substances produced during the cooking. Polymeric materials are good candidates for microwaveable packaging thanks to their transparency to MW. In the last years a great interest is devoted to developing innovative solution based on the use of additives or systems that act as susceptors or heating enhancers for improving the characteristics of polymers in cooking/heating in MW ovens. The present work was focused on the production and characterization of nanocomposite copolyester based films suitable for microwaveable food packaging applications. The matrices selected consist in two PET copolymers modified with carbon black (ULTRA STD) and with titanium oxide (ULTRA NA). Nanocomposite co-extruded multilayer films were produced using different percentages (0%, 2% and 4%wt/wt) of Cloisite 20A (C20A). Films were analyzed for evaluating the effect of nanofiller on the morphology and barrier properties. Moreover, to verify the effectiveness of the designed systems in reducing the cooking times of meat products, MW heating tests were carried out on pork meat hamburgers in MW oven at varying supplied powers. The cooking tests have pointed out that the selected matrices are efficient in reducing cooking times and that even low concentration of C20A acts as heating enhancers of PET.

  8. PET based nanocomposite films for microwave packaging applications

    SciTech Connect

    Galdi, M. R. Olivieri, R.; Liguori, L.; Albanese, D. Di Matteo, M.; Di Maio, L.

    2015-12-17

    In recent years, changes in life standards have promoted the diffusion of Ready to Cook (RTC) and Ready to Eat (RTE) products for microwave ovens. However, the main limits in microwave (MW) ovens usage are often related to the proper choice of packaging materials suitable for such technology. In fact, packages for microwaveable RTC and RTE foods should ensure adequate preservation of the product before cooking/heating such as high barriers to gases and aromas and adequate control of water vapor transmission. In addition, microwaveable packaging material must be transparent to MW, thermally stable and resistant to the mechanical stress induced by the accumulation in the head space of volatile substances produced during the cooking. Polymeric materials are good candidates for microwaveable packaging thanks to their transparency to MW. In the last years a great interest is devoted to developing innovative solution based on the use of additives or systems that act as susceptors or heating enhancers for improving the characteristics of polymers in cooking/heating in MW ovens. The present work was focused on the production and characterization of nanocomposite copolyester based films suitable for microwaveable food packaging applications. The matrices selected consist in two PET copolymers modified with carbon black (ULTRA STD) and with titanium oxide (ULTRA NA). Nanocomposite co-extruded multilayer films were produced using different percentages (0%, 2% and 4%wt/wt) of Cloisite 20A (C20A). Films were analyzed for evaluating the effect of nanofiller on the morphology and barrier properties. Moreover, to verify the effectiveness of the designed systems in reducing the cooking times of meat products, MW heating tests were carried out on pork meat hamburgers in MW oven at varying supplied powers. The cooking tests have pointed out that the selected matrices are efficient in reducing cooking times and that even low concentration of C20A acts as heating enhancers of PET.

  9. Multilevel Ge-Se Film Based Resist Systems

    NASA Astrophysics Data System (ADS)

    Tai, K. L.; Vadimsky, R. G.; Ong, E.

    1982-06-01

    Multilevel resist systems based on Ge-Se films make possible the use of optical projection printers for printing 0.5-1.0μm features. The four multilevel resist systems considered employ either a photosensitive or a photopassive polymer layer for planarization. In bilevel schemes the surface of the Ge-Se film is reacted in a Ag(CN)i- containing solution to form a Ag2Se imaging layer. No reacted Ge-Se is used as a sacrificial layer in trilevel schemes. Ge-Se films are resistant to attack by oxygen plasma and therefore make good masks for pattern transfer by dry (reactive ion) etching, to a thick underlying photopassive polymer layer. Because of their high absorbance (a 105cm-1) in the ultraviolet and violet, Ge-Se patterns can also be used as exposure masks for transferring images to a thick underlying photosensitive polymer layer. The latter is "flood" exposed through the Ge-Se mask and wet developed. Both dry and wet processes provide steep wall-profile patterns in the polymer layer. The dry process provides superior feature size control while the wet process offers reduced processing cost. The exceptional lithographic performance exhibited by Ge-Se resist systems is attributed to a unique edge-sharpening effect; diffraction is compensated for by lateral silver diffusion in the Ag2Se layer. Patterns having 0.6μm lines and spaces are obtained over lcmXlcm fields with a defocus tolerance of 2.5μm using a standard Zeiss 10:1 reduction lens (N.A.=0.28, λ=436nm). Results indicate that optical lithography can practically print features in the size regime previously reserved for a-beam or x-ray based lithographic technologies.

  10. Fast-response humidity-sensing films based on methylene blue aggregates formed on nanoporous semiconductor films

    NASA Astrophysics Data System (ADS)

    Ishizaki, Ryota; Katoh, Ryuzi

    2016-05-01

    We prepared fast-response colorimetric humidity-sensing (vapochromic) films based on methylene blue adsorption onto nanoporous semiconductor (TiO2, Al2O3) films. Color changes caused by changes of humidity could be easily identified visually. A characteristic feature of the vapochromic films was their fast response to changes of humidity. We found that the response began to occur within 10 ms. The response was rapid because all the methylene blue molecules attached to the nanoporous semiconductor surface were directly exposed to the environment. We also deduced that the color changes were caused by structural changes of the methylene blue aggregates on the surface.

  11. 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

  12. Solution-Processed Indium Oxide Based Thin-Film Transistors

    NASA Astrophysics Data System (ADS)

    Xu, Wangying

    Oxide thin-film transistors (TFTs) have attracted considerable attention over the past decade due to their high carrier mobility and excellent uniformity. However, most of these oxide TFTs are usually fabricated using costly vacuum-based techniques. Recently, the solution processes have been developed due to the possibility of low-cost and large-area fabrication. In this thesis, we have carried out a detailed and systematic study of solution-processed oxide thin films and TFTs. At first, we demonstrated a passivation method to overcome the water susceptibility of solution-processed InZnO TFTs by utilizing octadecylphosphonic acid (ODPA) self-assembled monolayers (SAMs). The unpassivated InZnO TFTs exhibited large hysteresis in their electrical characteristics due to the adsorbed water at the semiconductor surface. Formation of a SAM of ODPA on the top of InZnO removed water molecules weakly absorbed at the back channel and prevented water diffusion from the surroundings. Therefore the passivated devices exhibited significantly reduced hysteretic characteristics. Secondly, we developed a simple spin-coating approach for high- k dielectrics (Al2O3, ZrO2, Y 2O3 and TiO2). These materials were used as gate dielectrics for solution-processed In2O3 or InZnO TFTs. Among the high-k dielectrics, the Al2O3-based devices showed the best performance, which is attributed to the smooth dielectric/semiconductor interface and the low interface trap density besides its good insulating property. Thirdly, the formation and properties of Al2O3 thin films under various annealing temperatures were intensively studied, revealing that the sol-gel-derived Al2O3 thin film undergoes the decomposition of organic residuals and nitrate groups, as well as conversion of aluminum hydroxides to form aluminum oxide. Besides, the Al2O 3 film was used as gate dielectric for solution-processed oxide TFTs, resulting in high mobility and low operating voltage. Finally, we proposed a green route for

  13. 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.

  14. Release behavior and stability of encapsulated D-limonene from emulsion-based edible films.

    PubMed

    Marcuzzo, Eva; Debeaufort, Frédéric; Sensidoni, Alessandro; Tat, Lara; Beney, Laurent; Hambleton, Alicia; Peressini, Donatella; Voilley, Andrée

    2012-12-12

    Edible films may act as carriers of active molecules, such as flavors. This possibility confers to them the status of active packaging. Two different film-forming biopolymers, gluten and ι-carrageenans, have been compared. D-Limonene was added to the two film formulations, and its release kinetics from emulsion-based edible films was assessed with HS-SPME. Results obtained for edible films were compared with D-limonene released from the fatty matrix called Grindsted Barrier System 2000 (GBS). Comparing ι-carrageenans with gluten-emulsified film, the latter showed more interesting encapsulating properties: in fact, D-limonene was retained by gluten film during the process needed for film preparation, and it was released gradually during analysis time. D-Limonene did not show great affinity to ι-carrageenans film, maybe due to high aroma compound hydrophobicity. Carvone release from the three different matrices was also measured to verify the effect of oxygen barrier performances of edible films to prevent D-limonene oxidation. Further investigations were carried out by FT-IR and liquid permeability measurements. Gluten film seemed to better protect D-limonene from oxidation. Gluten-based edible films represent an interesting opportunity as active packaging: they could retain and release aroma compounds gradually, showing different mechanical and nutritional properties from those of lipid-based ingredients. PMID:23163743

  15. Elements of adaptive optics based on metallized polymer films

    NASA Astrophysics Data System (ADS)

    Voliak, T. B.; Krasiuk, I. K.; Pashinin, P. P.

    Results of an experimental study of the stability of metallized polymer films exposed to laser radiation at wavelengths of 1.06 and 10.6 microns are reported, and methods for fabricating variable-curvature mirrors from these films are discussed. Formulas are presented for calculating the shape of film mirrors as a function of the pressure acting on the film, mounting contour, and film properties. The performance of film mirrors is investigated experimentally in a pulsed CO2 laser with stable and unstable resonators.

  16. Process Modeling of Low-Pressure Die Casting of Aluminum Alloy Automotive Wheels

    NASA Astrophysics Data System (ADS)

    Reilly, C.; Duan, J.; Yao, L.; Maijer, D. M.; Cockcroft, S. L.

    2013-09-01

    Although on initial inspection, the aluminum alloy automotive wheel seems to be a relatively simple component to cast based on its shape, further insight reveals that this is not the case. Automotive wheels are in a select group of cast components that have strict specifications for both mechanical and aesthetic characteristics due to their important structural requirements and their visibility on a vehicle. The modern aluminum alloy automotive wheel continues to experience tightened tolerances relating to defects to improve mechanical performance and/or the physical appearance. Automotive aluminum alloy wheels are assessed against three main criteria: wheel cosmetics, mechanical performance, and air tightness. Failure to achieve the required standards in any one of these categories will lead to the wheel either requiring costly repair or being rejected and remelted. Manufacturers are becoming more reliant on computational process modeling as a design tool for the wheel casting process. This article discusses and details examples of the use of computational process modeling as a predictive tool to optimize the casting process from the standpoint of defect minimization with the emphasis on those defects that lead to failure of aluminum automotive wheels, namely, macroporosity, microporosity, and oxide films. The current state of applied computational process modeling and its limitations with regard to wheel casting are discussed.

  17. A facile route to prepare cellulose-based films.

    PubMed

    Xu, Qin; Chen, Chen; Rosswurm, Katelyn; Yao, Tianming; Janaswamy, Srinivas

    2016-09-20

    Cellulose is the most abundant renewable and biodegradable material available in nature. Its insoluble character in water as well as common organic and inorganic liquids, however, curtails the wholesome utility. The continuous rise for biodegradable products based on cellulose coupled with its intrinsic ability to form a viable substitute for the petroleum-based materials necessitates the critical need for solubilizing the cellulose. Herein, we demonstrate the feasibility of ZnCl2 solutions, especially the 64-72% concentrations, to dissolve cellulose. FTIR results suggest that Zn(2+) ions promote Zn⋯O3H interactions, which in-turn weaken the intrinsic O3H⋯O5 hydrogen bonds that are responsible for strengthening the cellulose chains. Interestingly, Ca(2+) ions promote interactions among the Zn-cellulose chains leading to the formation of nano fibrils and yield gelling solutions. The tensile strength of the Ca(2+) added Zn-cellulose films increases by around 250% compared to the Zn-cellulose films. Overall, utilization of inorganic salt solutions to solubilize and crosslink cellulose is cost-effective, recyclable and certainly stands out tall among the other available systems. More importantly, the proposed protocol is simple and is a "green" process, and thus its large-scale adaptability is quite feasible. We strongly believe that the outcome opens up a new window of opportunities for cellulose in the biomedical, pharmaceutical, food and non-food applications. PMID:27261751

  18. Fabrication of graphene-based films using remote plasma CVD

    NASA Astrophysics Data System (ADS)

    Hiramatsu, Mineo; Tsukada, Ryosuke; Kashima, Yohei; Naito, Masateru; Kondo, Hiroki; Hori, Masaru

    2012-10-01

    Plasma-enhanced CVD (PECVD) employing methane/hydrogen gases has been used to grow diamond, diamond-like carbon, and carbon nanotubes. In the case of microwave PECVD with methane/hydrogen system without catalyst nanoparticles at temperatures of 700--850 ^oC, where the substrate is exposed to the plasma, vertical nano-graphenes and carbon nanoflakes have been easily grown even on Cu substrate due to the ion bombardment and local electric field forces. In this work, we demonstrate the synthesis of planar few-layer graphene-based film using PECVD with remote plasma configuration. In the case using microwave plasma of cylindrical resonant cavity type, by simply installing grounded grid over the substrate plate for obtaining remote plasma configuration, we have successfully fabricated graphene-based films on Cu substrate, which was confirmed by the Raman spectrum and SEM image of deposit. Similar method will be applied to other plasmas such as low-pressure inductively coupled plasma, in order to verify the effectiveness of remote plasma configuration for the growth of planar graphene using PECVD technique. We will discuss the planar graphene growth mechanism in terms of precursors and their surface reaction.

  19. Direct formation of L10 FePt in as-cast FePt-based magnetic nanocomposite ribbons without post-synthesis annealing

    NASA Astrophysics Data System (ADS)

    Crisan, A. D.; Crisan, O.

    2011-09-01

    A novel nanocomposite FePt-based exchange-coupled magnet has been synthesized and structurally and magnetically characterized. We report for the first time the direct formation of the L10 FePt phase without the need for post-synthesis annealing procedures in Fe-Pt-based melt-spun ribbons, obtained by a conventional melt spinning method. The structure and magnetic properties are investigated and the occurrence of the L10 ordered phase in the as-cast state of Fe-Pt-Ag-B melt-spun ribbons is confirmed by XRD and magnetic measurements. A microstructure consisting of fine, uniformly dispersed, 22-24 nm FePt grains dispersed within a soft magnetic matrix is observed by scanning transmission electron microscopy imaging. Coercive fields as high as 727 kA m-1, saturation magnetization of about 1.2 T and energy product around 87 kJ m-3 are determined from 270 K hysteresis loops of the as-cast ribbons, making one of the best FePt-based nanocomposite magnet ribbons even without further annealing treatments.

  20. A novel white film for pharmaceutical coating formed by interaction of calcium lactate pentahydrate with hydroxypropyl methylcellulose.

    PubMed

    Sakata, Yukoh; Shiraishi, Sumihiro; Otsuka, Makoto

    2006-07-24

    We have found that a white film forms on tablets when a coating solution consisting of hydroxypropyl methylcellulose (HPMC), polyethylene glycol (PEG 6000) and calcium lactate pentahydrate (CLP) is used. The white film has also been found in casting film consisting of HPMC and CLP, and the surface state of coated tablets has been shown to be strongly affected by addition of PEG 6000. The aim of the present study was to investigate the mechanism of formation of this white film in order to derive an appropriate film prescription. Interaction among the base ingredients of the film was investigated using differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD) and Fourier transform-infrared (FT-IR) spectroscopy. The casting film formed with HPMC and a large excess of PEG 6000 was found to be crystalline in form. In contrast, the amorphous film consisting of HPMC, PEG 6000 and excess CLP exhibited the crystallinity film by an excess addition of CLP. Although the crystalline film had many cracks, the amorphous film appeared to be excellent as a tablet coating. The most probable interaction sites between HPMC and CLP were demonstrated by FT-IR analysis of casting films consisting of HPMC, CLP and PVP. PMID:16621357

  1. 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

  2. The present status of dental titanium casting

    NASA Astrophysics Data System (ADS)

    Okabe, Toru; Ohkubo, Chikahiro; Watanabe, Ikuya; Okuno, Osamu; Takada, Yukyo

    1998-09-01

    Experimentation in all aspects of titanium casting at universities and industries throughout the world for the last 20 years has made titanium and titanium-alloy casting nearly feasible for fabricating sound cast dental prostheses, including crowns, inlays, and partial and complete dentures. Titanium casting in dentistry has now almost reached the stage where it can seriously be considered as a new method to compete with dental casting using conventional noble and base-metal alloys. More than anything else, the strength of titanium’s appeal lies in its excellent biocompatibility, coupled with its comparatively low price and abundant supply. Research efforts to overcome some problems associated with this method, including studies on the development of new titanium alloys suitable for dental use, will continue at many research sites internationally.

  3. 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.

  4. Physicochemical properties of alginate/polycaprolactone-based films containing essential oils.

    PubMed

    Salmieri, Stéphane; Lacroix, Monique

    2006-12-27

    Oregano, savory, and cinnamon essential oils (EOs) 1% (w/v) were separately incorporated as natural antioxidant agents in alginate/polycaprolactone-based films. Films were then treated in 2 or 20% (w/v) CaCl2 solutions in order to generate insoluble films. The mechanical properties and the insoluble matter of films were determined. Intermolecular interactions between film components and alginate cross-linkage were characterized by Fourier transform infrared (FTIR) spectroscopy. Surface morphology of the polymer membrane was determined by scanning electron microscopy (SEM) analysis. Antiradical properties of films were also evaluated following a modified colorimetric method using the N,N-diethyl-p-phenylenediamine (DPPD) discoloration test. Results showed that films treatment with CaCl2 (20%) solution increased the percentage of insoluble matter in films but did not enhance their mechanical properties. FTIR analysis showed higher interactions in films treated in CaCl2 solutions despite the concentration used (2 vs 20%). The SEM observations of films showed a smoother surface with a higher density when films were treated in CaCl2 (20%) solution. The DPPD test showed that the oregano-based films had the highest antiradical properties. PMID:17177561

  5. Polyhydroxyalkanoate-based natural synthetic hybrid copolymer films: A small-angle neutron scattering study

    NASA Astrophysics Data System (ADS)

    Foster, L. John R.; Knott, Robert; Sanguanchaipaiwong, Vorapat; Holden, Peter J.

    2006-11-01

    Polyhydroxyalkanoates have attracted attention as biodegradable alternatives to conventional thermoplastics and as biomaterials. Through modification of their biosynthesis using Pseudomonas oleovorans, we have manipulated the material properties of these biopolyesters and produced a natural-synthetic hybrid copolymer of polyhydroxyoctanoate- block-diethylene glycol (PHO- b-DEG). A mixture of PHO and PHO-DEG were solvent cast from analytical grade chloroform and analysed using small-angle neutron scattering. A scattering pattern, easily distinguished above the background, was displayed by the films with a diffraction ring at q∼0.12 Å -1. This narrow ring of intensity is suggestive of a highly ordered system. Analysis of the diffraction pattern supported this concept and showed a d-spacing of approximately 50 Å. In addition, conformation of the hybrid polymer chains can be manipulated to support their self-assembly into ordered microporous films.

  6. Large area radiation detectors based on II VI thin films

    NASA Astrophysics Data System (ADS)

    Quevedo-Lopez, Manuel

    2015-03-01

    The development of low temperature device technologies that have enabled flexible displays also present opportunities for flexible electronics and flexible integrated systems. Of particular interest are possible applications in flexible, low metal content, sensor systems for unattended ground sensors, smart medical bandages, electronic ID tags for geo-location, conformal antennas, neutron/gamma-ray/x-ray detectors, etc. In this talk, our efforts to develop novel CMOS integration schemes, circuits, memory, sensors as well as novel contacts, dielectrics and semiconductors for flexible electronics are presented. In particular, in this presentation we discuss fundamental materials properties including crystalline structure, interfacial reactions, doping, etc. defining performance and reliability of II-VI-based radiation sensors. We investigate the optimal thickness of a semiconductor diode for thin-film solid state thermal neutron detectors. Besides II-VI materials, we also evaluated several diode materials, Si, CdTe,GaAs, C (diamond), and ZnO, and two neutron converter materials,10B and 6LiF. We determine the minimum semiconductor thickness needed to achieve maximum neutron detection efficiency. By keeping the semiconductor thickness to a minimum, gamma rejection is kept as high as possible. In this way, we optimize detector performance for different thin-film semiconductor materials.

  7. Crack width monitoring of concrete structures based on smart film

    NASA Astrophysics Data System (ADS)

    Zhang, Benniu; Wang, Shuliang; Li, Xingxing; Zhang, Xu; Yang, Guang; Qiu, Minfeng

    2014-04-01

    Due to its direct link to structural security, crack width is thought to be one of the most important parameters reflecting damage conditions of concrete structures. However, the width problem is difficult to solve with the existing structural health monitoring methods. In this paper, crack width monitoring by means of adhering enameled copper wires with different ultimate strains on the surface of structures is proposed, based on smart film crack monitoring put forward by the present authors. The basic idea of the proposed method is related to a proportional relationship between the crack width and ultimate strain of the broken wire. Namely, when a certain width of crack passes through the wire, some low ultimate strain wires will be broken and higher ultimate strain wires may stay non-broken until the crack extends to a larger scale. Detection of the copper wire condition as broken or non-broken may indicate the width of the structural crack. Thereafter, a multi-layered stress transfer model and specimen experiment are performed to quantify the relationship. A practical smart film is then redesigned with this idea and applied to Chongqing Jiangjin Yangtze River Bridge.

  8. SLIP CASTING METHOD

    DOEpatents

    Allison, A.G.

    1959-09-01

    S>A process is described for preparing a magnesium oxide slip casting slurry which when used in conjunction with standard casting techniques results in a very strong "green" slip casting and a fired piece of very close dimensional tolerance. The process involves aging an aqueous magnestum oxide slurry, having a basic pH value, until it attains a specified critical viscosity at which time a deflocculating agent is added without upsetting the basic pH value.

  9. Bamboo (Neosinocalamus affinis)-based thin film, a novel biomass material with high performances.

    PubMed

    Song, Fei; Xu, Chen; Bao, Wen-Yi; Wang, Xiu-Li; Wang, Yu-Zhong

    2015-03-30

    Exploration of biomass based materials to replace conventional petroleum based ones has been a trend in recent decades. In this work, bamboo (Neosinocalamus affinis) with abundant resources was used for the first time to prepare films in the presence of cellulose. The effects of weight ratio of bamboo/cellulose on the appearances and properties of the films were investigated. It was confirmed there existed strong interactions between bamboo and cellulose, which were favorable to formation of homogeneous structure of blend films. Particularly, the presence of bamboo could improve the surface hydrophobicity, water resistance and thermal stability of blend films, and the films possessed an excellent oxygen barrier property, compared with generally used commercial packaging films. The bamboo biomass, therefore, is successfully used to create a new film material with a good application prospect in the fields of packaging, coating, and food industry. PMID:25563957

  10. 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.

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

    SciTech Connect

    Jensen, D.

    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.

  12. 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

    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.

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

    NASA Astrophysics Data System (ADS)

    Zhang, Hongliang; Wan, Qing; Wan, Changjin; Wu, Guodong; Zhu, Liqiang

    2013-02-01

    Tungsten oxide (WOx) electrolyte films deposited by reactive magnetron sputtering showed a high room temperature proton conductivity of 1.38 × 10-4 S/cm with a relative humidity of 60%. Low-voltage transparent W-doped indium-zinc-oxide thin-film transistors gated by WOx-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 × 106, a low subthreshold swing of 108 mV/decade, and a high field-effect mobility 42.6 cm2/V s was realized. Our results demonstrated that WOx-based proton conducting films were promising gate dielectric candidates for portable low-voltage oxide-based devices.

  14. A micromachined carbon nanotube film cantilever-based energy cell.

    PubMed

    Gong, Zhongcheng; He, Yuan; Tseng, Yi-Hsuan; O'Neal, Chad; Que, Long

    2012-08-24

    This paper reports a new type of energy cell based on micromachined carbon nanotube film (CNF)-lead zirconate titanate cantilevers that is fabricated on silicon substrates. Measurements found that this type of micro-energy cell generates both AC voltages due to the self-reciprocation of the microcantilevers and DC voltages due to the thermoelectric effect upon exposure to light and thermal radiation, resulting from the unique optical and thermal properties of the CNF. Typically the measured power density of the micro-energy cell can be from 4 to 300 μW cm(-2) when it is exposed to sunlight under different operational conditions. It is anticipated that hundreds of integrated micro-energy cells can generate power in the range of milliwatts, paving the way for the construction of self-powered micro- or nanosystems. PMID:22842491

  15. LTCC Phase Shifters Based on Tunable Ferroelectric Composite Thick Films

    NASA Astrophysics Data System (ADS)

    Nikfalazar, M.; Kohler, C.; Heunisch, A.; Wiens, A.; Zheng, Y.; Schulz, B.; Mikolajek, M.; Sohrabi, M.; Rabe, T.; Binder, J. R.; Jakoby, R.

    2015-11-01

    This paper presents, the investigation of tunable components based on LTCC technology, implementing ferroelectric tunable thick-film dielectric. The tunable loaded line phase shifters are fabricated with metal-insulator-metal (MIM) varactors to demonstrate the capabilities of this method for packaging of the tunable components. The MIM varactors consist of one tunable dielectric paste layer that is printed between two silver layers. The tunable ferroelectric paste is optimized for LTCC sintering temperature around 850°C. The phase shifters are fabricated in two different process. They were achieved a figure of merit of 24°/dB (phase shift 192°) at 3 GHz and 18°/dB (phase shift 98°) at 4.4 GHz by using seven unit cells that each unit cell consisting of two MIM varactors.

  16. Graphene-based electrodes for enhanced organic thin film transistors based on pentacene.

    PubMed

    Basu, Sarbani; Lee, Mu Chen; Wang, Yeong-Her

    2014-08-21

    This paper presents 6,13-bis(triisopropylsilylethynyl)pentacene (TIPS-pentacene) and pentacene-based organic thin film transistors (OTFTs) with monolayer graphene source-drain (S-D) electrodes. The electrodes are patterned using conventional photolithographic techniques combined with reactive ion etching. The monolayer graphene film grown by chemical vapor deposition on Cu foil was transferred on a Si dioxide surface using a polymer-supported transfer method to fabricate bottom-gate, bottom-contact OTFTs. The pentacene OTFTs with graphene S-D contacts exhibited superior performance with a mobility of 0.1 cm(2) V(-1) s(-1) and an on-off ratio of 10(5) compared with OTFTs with Au-based S-D contacts, which had a mobility of 0.01 cm(2) V(-1) s(-1) and an on-off ratio of 10(3). The crystallinity, grain size, and microscopic defects (or the number of layers of graphene films) of the TIPS-pentacene/pentacene films were analyzed by X-ray diffraction spectroscopy, atomic force microscopy, and Raman spectroscopy, respectively. The feasibility of using graphene as an S-D electrode in OTFTs provides an alternative material with high carrier injection efficiency, chemical stability, and excellent interface properties with organic semiconductors, thus exhibiting improved device performance of C-based electronic OTFTs at a reduced cost. PMID:25000388

  17. 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.

  18. 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.

  19. A fast and efficient adaptive parallel ray tracing based model for thermally coupled surface radiation in casting and heat treatment processes

    NASA Astrophysics Data System (ADS)

    Fainberg, J.; Schaefer, W.

    2015-06-01

    A new algorithm for heat exchange between thermally coupled diffusely radiating interfaces is presented, which can be applied for closed and half open transparent radiating cavities. Interfaces between opaque and transparent materials are automatically detected and subdivided into elementary radiation surfaces named tiles. Contrary to the classical view factor method, the fixed unit sphere area subdivision oriented along the normal tile direction is projected onto the surrounding radiation mesh and not vice versa. Then, the total incident radiating flux of the receiver is approximated as a direct sum of radiation intensities of representative “senders” with the same weight factor. A hierarchical scheme for the space angle subdivision is selected in order to minimize the total memory and the computational demands during thermal calculations. Direct visibility is tested by means of a voxel-based ray tracing method accelerated by means of the anisotropic Chebyshev distance method, which reuses the computational grid as a Chebyshev one. The ray tracing algorithm is fully parallelized using MPI and takes advantage of the balanced distribution of all available tiles among all CPU's. This approach allows tracing of each particular ray without any communication. The algorithm has been implemented in a commercial casting process simulation software. The accuracy and computational performance of the new radiation model for heat treatment, investment and ingot casting applications is illustrated using industrial examples.

  20. Comparison of Structural Relaxation Behavior in As-Cast and Pre-Annealed Zr-Based Bulk Metallic Glasses Just below Glass Transition

    DOE PAGESBeta

    Haruyama, Osami; Yoshikawa, Kazuyoshi; Yamazaki, Yoshikatsu; Yokoyama, Yoshihiko; Egami, Takeshi

    2015-04-25

    In this paper, the α-relaxation of pre-annealed Zr55Cu30Ni5Al10 bulk metallic glasses (BMGs) was compared with that of as-cast Zr-based BMGs including Zr55Cu30Ni5Al10. The α-relaxation was investigated by volume relaxation. The relaxation behavior was well described by a stretched exponential relaxation function, Φ (t) ≈ exp [ - (t/τ α )β α ], with the isothermal relaxation time, τα, and the Kohlrausch exponent, βα. The βα exhibited the strong temperature dependence for the pre-annealed BMG, while the weak temperature dependence was visualized for the as-cast BMG similar to the dynamic relaxation. The τα’s were modified by Moynihan and Narayanaswamy-Tool-Moynihan methods thatmore » reduce the difference in the thermal history of sample. Finally, as a result, the relaxation kinetics in the glass resembled that of a liquid deduced from the behavior of viscosity in the supercooled liquid.« less

  1. Comparison of Structural Relaxation Behavior in As-Cast and Pre-Annealed Zr-Based Bulk Metallic Glasses Just below Glass Transition

    SciTech Connect

    Haruyama, Osami; Yoshikawa, Kazuyoshi; Yamazaki, Yoshikatsu; Yokoyama, Yoshihiko; Egami, Takeshi

    2015-04-25

    In this paper, the α-relaxation of pre-annealed Zr55Cu30Ni5Al10 bulk metallic glasses (BMGs) was compared with that of as-cast Zr-based BMGs including Zr55Cu30Ni5Al10. The α-relaxation was investigated by volume relaxation. The relaxation behavior was well described by a stretched exponential relaxation function, Φ (t) ≈ exp [ - (t/τ α )β α ], with the isothermal relaxation time, τα, and the Kohlrausch exponent, βα. The βα exhibited the strong temperature dependence for the pre-annealed BMG, while the weak temperature dependence was visualized for the as-cast BMG similar to the dynamic relaxation. The τα’s were modified by Moynihan and Narayanaswamy-Tool-Moynihan methods that reduce the difference in the thermal history of sample. Finally, as a result, the relaxation kinetics in the glass resembled that of a liquid deduced from the behavior of viscosity in the supercooled liquid.

  2. Effect of plasticizer type and concentration on physical properties of biodegradable films based on sugar palm (arenga pinnata) starch for food packaging.

    PubMed

    Sanyang, M L; Sapuan, S M; Jawaid, M; Ishak, M R; Sahari, J

    2016-01-01

    In this study, sugar palm starch (SPS) films were developed using glycerol (G), sorbitol (S) or their combination (GS) as plasticizers at the ratio of 15, 30 and 45 (wt)% using casting technique. The addition of plasticizers to SPS film-forming solutions helped to overcome the brittle and fragile nature of unplasticized SPS films. Increased plasticizer concentration resulted to an increase in film thickness, moisture content and solubility. On the contrary, density and water absorption of plasticized films decreased with increasing plasticizer concentration. Raising the plasticizer content from 15 to 45 % showed less effect on the moisture content and water absorption of S-plasticized films. Films containing glycerol and glycerol-sorbitol plasticizer (G, and GS) demonstrated higher moisture content, solubility and water absorption capacity compared to S-plasticized films. The results obtained in this study showed that plasticizer type and concentration significantly improves film properties and enhances their suitability for food packaging applications. PMID:26787952

  3. High performance thin film transistors based on regioregular poly(3-dodecylthiophene)-sorted large diameter semiconducting single-walled carbon nanotubes

    NASA Astrophysics Data System (ADS)

    Wang, Chao; Qian, Long; Xu, Wenya; Nie, Shuhong; Gu, Weibing; Zhang, Jianhui; Zhao, Jianwen; Lin, Jian; Chen, Zheng; Cui, Zheng

    2013-05-01

    In this work, a simple and rapid method to selectively sort semiconducting-SWCNTs (sc-SWCNTs) with large diameters using regioregular poly(3-dodecylthiophene) (rr-P3DDT) is presented. The absorption spectra and Raman spectra demonstrated that metallic species of arc discharge SWCNTs were effectively removed after interaction with rr-P3DDT in toluene with the aid of sonication and centrifugation. The sorted sc-SWCNT inks have been directly used to fabricate thin film transistors (TFTs) by dip-coating, drop-casting and inkjet printing. TFTs with an effective mobility of ~34 cm2 V-1 s-1 and on-off ratios of ~107 have been achieved by dip coating and drop casting the ink on SiO2/Si substrates with pre-patterned interdigitated gold electrode arrays. The printed devices also showed excellent electrical properties with a mobility of up to 6.6 cm2 V-1 s-1 and on-off ratios of up to 105. Printed inverters based on the TFTs have been constructed on glass substrates, showing a maximum voltage gain of 112 at a Vdd of -5 V. This work paves the way for making printable logic circuits for real applications.In this work, a simple and rapid method to selectively sort semiconducting-SWCNTs (sc-SWCNTs) with large diameters using regioregular poly(3-dodecylthiophene) (rr-P3DDT) is presented. The absorption spectra and Raman spectra demonstrated that metallic species of arc discharge SWCNTs were effectively removed after interaction with rr-P3DDT in toluene with the aid of sonication and centrifugation. The sorted sc-SWCNT inks have been directly used to fabricate thin film transistors (TFTs) by dip-coating, drop-casting and inkjet printing. TFTs with an effective mobility of ~34 cm2 V-1 s-1 and on-off ratios of ~107 have been achieved by dip coating and drop casting the ink on SiO2/Si substrates with pre-patterned interdigitated gold electrode arrays. The printed devices also showed excellent electrical properties with a mobility of up to 6.6 cm2 V-1 s-1 and on-off ratios of up to 105

  4. Evaluation of the Influence of Formulation and Process Variables on Mechanical Properties of Oral Mucoadhesive Films Using Multivariate Data Analysis

    PubMed Central

    Landová, Hana; Gajdziok, Jan; Doležel, Petr; Muselík, Jan; Dvořáčková, Kateřina; Jekl, Vladimír; Hauptman, Karel

    2014-01-01

    Oral mucosa is an attractive region for the local and systemic application of many drugs. Oral mucoadhesive films are preferred for their prolonged time of residence, the improved bioavailability of the drug they contain, their painless application, their protection against lesions, and their nonirritating properties. This work was focused on preparation of nonmedicated carmellose-based films using both solvent casting and impregnation methods, respectively. Moreover, a modern approach to evaluation of mucoadhesive films applying analysis of texture and subsequent multivariate data analysis was used. In this experiment, puncture strength strongly correlated with tensile strength and could be used to obtain necessary information about the mechanical film characteristics in films prepared using both methods. Puncture work and tensile work were not correlated in films prepared using the solvent casting method, as increasing the amount of glycerol led to an increase in the puncture work in thinner films. All measured texture parameters in films prepared by impregnation were significantly smaller compared to films prepared by solvent casting. Moreover, a relationship between the amount of glycerol and film thickness was observed, and a greater recalculated tensile/puncture strength was needed for an increased thickness in films prepared by impregnation. PMID:25136560

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

    NASA Astrophysics Data System (ADS)

    Mushi, Ngesa; Utsel, Simon; Berglund, Lars

    2014-11-01

    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 nanostructured biocomposite was produced in volume fractions of 0, 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.

  6. Air-Flow Navigated Crystal Growth for TIPS Pentacene-Based Organic Thin-Film Transistors

    SciTech Connect

    He, Zhengran; Chen, Jihua; Sun, Zhenzhong; Szulczewski, Greg; Li, Dawen

    2012-01-01

    6,13-bis(triisopropylsilylethynyl)pentacene (TIPS pentacene) is a promising active channel material of organic thin-film transistors (OTFTs) due to its solubility, stability, and high mobility. However, the growth of TIPS pentacene crystals is intrinsically anisotropic and thus leads to significant variation in the performance of OTFTs. In this paper, air flow is utilized to effectively reduce the TIPS pentacene crystal anisotropy and enhance performance consistency in OTFTs, and the resulted films are examined with optical microscopy, grazing-incidence X-ray diffraction, and thin-film transistor measurements. Under air-flow navigation (AFN), TIPS pentacene drop-cast from toluene solution has been observed to form thin films with improved crystal orientation and increased areal coverage on substrates, which subsequently lead to a four-fold increase of average hole mobility and one order of magnitude enhancement in performance consistency defined by the ratio of average mobility to the standard deviation of the field-effect mobilities.

  7. Alcohol vapor sensing by cadmium-doped zinc oxide thick films based chemical sensor

    NASA Astrophysics Data System (ADS)

    Zargar, R. A.; Arora, M.; Chackrabarti, S.; Ahmad, S.; Kumar, J.; Hafiz, A. K.

    2016-04-01

    Cadmium-doped zinc oxide nanoparticles were derived by simple chemical co-precipitation route using zinc acetate dihydrate and cadmium acetate dihydrate as precursor materials. The thick films were casted from chemical co-precipitation route prepared nanoparticles by economic facile screen printing method. The structural, morphological, optical and electrical properties of the film were characterized relevant to alcohol vapor sensing application by powder XRD, SEM, UV-VIS and DC conductivity techniques. The response and sensitivity of alcohol (ethanol) vapor sensor are obtained from the recovery curves at optimum working temperature range from 20∘C to 50∘C. The result shows that maximum sensitivity of the sensor is observed at 25∘C operating temperature. On varying alcohol vapor concentration, minor variation in resistance has been observed. The sensing mechanism of sensor has been described in terms of physical adsorption and chemical absorption of alcohol vapors on cadmium-doped zinc oxide film surface and inside film lattice network through weak hydrogen bonding, respectively.

  8. 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

  9. Analysis of the permeation and mechanical characteristics of some aqueous-based film coating systems.

    PubMed

    Okhamafe, A O; York, P

    1983-07-01

    The moisture permeability and mechanical properties of some aqueous-based free films have been evaluated using sorption-desorption and stress-strain techniques, respectively. These properties for blends of two film-formers--hydroxypropyl methylcellulose and polyvinyl alcohol--have been compared with those of hydroxypropyl methylcellulose films plasticized with polyethylene glycols. The polyethylene glycols generally increased the moisture permeability of hydroxypropyl methylcellulose films while polyvinyl alcohol decreased it. Both polyvinyl alcohol and the polyethylene glycols lowered tensile strength at break and Young's modulus but the effects of the polyethylene glycols were more pronounced. These results are discussed in terms of structural interactions between film components. All film systems evaluated, except that containing hydroxypropyl methylcellulose alone, exhibited a degree of anisotropy, a phenomenon with potentially adverse consequences in tablet film coating. PMID:6136580

  10. Ultrasmooth and thermally stable silver-based thin films with subnanometer roughness by aluminum doping.

    PubMed

    Gu, Deen; Zhang, Cheng; Wu, Yi-Kuei; Guo, L Jay

    2014-10-28

    Rough surface and poor stability of ultrathin Ag films limit their applications in nanophotonic and optoelectronic devices. Here, we report an approach for fabricating ultrasmooth and thermally stable Ag-based thin films on SiO2/Si substrates by Al-doping. The effect of Al-doping on the surface morphology and stability of ultrathin Ag films at room temperature and elevated temperature was investigated. The 15 nm Al-doped Ag films with an Al atomic concentration of 4% have a root-mean-square roughness as low as 0.4 nm. The smooth surface morphology is maintained even after 300 °C annealing in N2. Al-doping enhances the nuclei density of films. Moreover, a capping layer spontaneously formed over the Al-doped Ag films restrains the surface diffusion and mass transportation of Ag atoms. Therefore, Al-doping induces ultrathin Ag films with highly stable and ultrasmooth surface morphology. PMID:25211394

  11. Transmission enhancement based on strong interference in metal-semiconductor layered film for energy harvesting

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Du, Kaikai; Mao, Kening; Fang, Xu; Zhao, Ding; Ye, Hui; Qiu, Min

    2016-07-01

    A fundamental strategy to enhance optical transmission through a continuous metallic film based on strong interference dominated by interface phase shift is developed. In a metallic film coated with a thin semiconductor film, both transmission and absorption are simultaneously enhanced as a result of dramatically reduced reflection. For a 50-nm-thick Ag film, experimental transmission enhancement factors of 4.5 and 9.5 are realized by exploiting Ag/Si non-symmetric and Si/Ag/Si symmetric geometries, respectively. These planar layered films for transmission enhancement feature ultrathin thickness, broadband and wide-angle operation, and reduced resistance. Considering one of their potential applications as transparent metal electrodes in solar cells, a calculated 182% enhancement in the total transmission efficiency relative to a single metallic film is expected. This strategy relies on no patterned nanostructures and thereby may power up a wide spectrum of energy-harvesting applications such as thin-film photovoltaics and surface photocatalysis.

  12. Casting Footprints for Eternity

    NASA Technical Reports Server (NTRS)

    1999-01-01

    Apollo 11 Astronaut Buzz Aldrin has his footprints casted during the dedication ceremony of the rocket fountain at Building 4200 at Marshall Space Flight Center. The casts of Aldrin's footprints will be placed in the newly constructed Von Braun courtyard representing the accomplishments of the Apollo 11 lunar landing.

  13. 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.

  14. Moving beyond "Bookish Knowledge": Using Film-Based Assignments to Promote Deep Learning

    ERIC Educational Resources Information Center

    Olson, Joann S.; Autry, Linda; Moe, Jeffry

    2016-01-01

    This article investigates the effectiveness of a film-based assignment given to adult learners in a graduate-level group counseling class. Semi-structured interviews were conducted with four students; data analysis suggested film-based assignments may promote deep approaches to learning (DALs). Participants indicated the assignment helped them…

  15. Optical Sensors Based on Single Arm Thin Film Waveguide Interferometer

    NASA Technical Reports Server (NTRS)

    Sarkisov, S. S.; Diggs, D.; Curley, M.; Adamovsky, Grigory (Technical Monitor)

    2001-01-01

    Single-arm double-mode double-order optical waveguide interferometer utilizes interference between two propagating modes of different orders. Sensing effect results from the change in propagation conditions of the modes caused by the environment. The waveguide is made as an open asymmetric slab structure containing a dye-doped polymer film onto a fused quartz substrate. It is more sensitive to the change of environment than its conventional polarimetric analog using orthogonal modes (TE and TM) of the same order. The sensor still preserves the option of operating in polarimetric regime using a variety of mode combinations such as TE(sub 0)/TM(sub 0) (conventional), TE(sub 0)/TM(sub 1), TE(sub 1)/TM(sub 0), or TE(sub 1)/TM(sub 1) but can also work in nonpolarimetric regime using combinations TE(sub 0)/TM(sub 1) or TE(sub 0)/TM(sub 1). Utilization of different mode combinations simultaneously makes the device more versatile. Application of the sensor to gas sensing is based on doping polymer film with an organic indicator dye sensitive to a particular gas. Change of optical absorption spectrum of the dye caused by the gaseous pollutant results change of the reactive index of the dye-doped polymer film that can be detected by the sensor. As an indicator dyes, we utilize Bromocresol Purple doped into polymer poly(methyl) methacrylate, which shows a reversible growth of the absorption peak neat 600 nm after exposure to wet ammonia. We have built a breadboard prototype of the sensor with He-Ne laser as a light source and with a single mode fiber input and a multimode fiber output. The prototype showed sensitivity to temperature change of the order of 2 C per one full oscillation of the signal. The sensitivity of the sensor to the presence of wet ammonia is 200 ppm per one full oscillation of the signal. The further improvements include switching to a longer wavelength laser source (750-nm semiconductor laser), substitution of poly(methyl) methacrylate with hydrophilic

  16. Organic Solar Cells Based on Electrodeposited Polyaniline Films

    NASA Astrophysics Data System (ADS)

    Inoue, Kei; Akiyama, Tsuyoshi; Suzuki, Atsushi; Oku, Takeo

    2012-04-01

    Polyaniline thin films as hole transporting layers were fabricated on transparent indium-tin-oxide electrodes by electrodeposition of aniline in an aqueous H2SO4 electrolyte solution. Emerald-green polyaniline films were obtained, which showed stable redox waves. A mixed solution of polythiophene and fullerene derivative was spin-coated onto the electrodeposited polyaniline film. After the modification of titanium oxide film on the surface of the polythiophene/fullerene layer, an aluminum electrode was fabricated by vacuum deposition. The obtained solar cells generated stable photocurrent and photovoltage under light illumination.

  17. Films based on oxidized starch and cellulose from barley.

    PubMed

    El Halal, Shanise Lisie Mello; Colussi, Rosana; Deon, Vinícius Gonçalves; Pinto, Vânia Zanella; Villanova, Franciene Almeida; Carreño, Neftali Lenin Villarreal; Dias, Alvaro Renato Guerra; Zavareze, Elessandra da Rosa

    2015-11-20

    Starch and cellulose fibers were isolated from grains and the husk from barley, respectively. Biodegradable films of native starch or oxidized starches and glycerol with different concentrations of cellulose fibers (0%, 10% and 20%) were prepared. The films were characterized by morphological, mechanical, barrier, and thermal properties. Cellulose fibers isolated from the barley husk were obtained with 75% purity and high crystallinity. The morphology of the films of the oxidized starches, regardless of the fiber addition, was more homogeneous as compared to the film of the native starch. The addition of cellulose fibers in the films increased the tensile strength and decreased elongation. The water vapor permeability of the film of oxidized starch with 20% of cellulose fibers was lower than the without fibers. However the films with cellulose fibers had the highest decomposition with the initial temperature and thermal stability. The oxidized starch and cellulose fibers from barley have a good potential for use in packaging. The addition of cellulose fibers in starch films can contribute to the development of films more resistant that can be applied in food systems to maintain its integrity. PMID:26344323

  18. Polyester-based thin films with high photosensitivity

    SciTech Connect

    POTTER,KELLY SIMMONS; POTTER JR.,BARRETT G.; WHEELER,DAVID R.; JAMISON,GREGORY M.

    2000-02-29

    A great deal of research has been done to understand the photosensitive optical response of inorganic glasses, which exhibit a permanent, photo-induced refractive index change due to the presence of optically active point defects in the glass structure. In the present work, the authors have performed a preliminary study of the intrinsic photosensitivity of a polyester containing a cinnamylindene malonate group (CPE, a photo- and thermal-crosslinkable group) for use in photonic waveguide devices. Thin films of CPE (approximately 0.5 microns thick) were spun onto fused silica substrates. Optical absorption in the thin films was evaluated both before and after exposure to UV radiation sources. It was found that the polyester exhibits two dominant UV absorption bands centered about 240 nm and 330 nm. Under exposure to 337 nm radiation (nitrogen laser) a marked bleaching of the 330 nm band was observed. This band bleaching is a direct result of the photo-induced crosslinking in the cinnamylindene malonate group. Exposure to 248 nm radiation (excimer laser), conversely, resulted in similar bleaching of the 330 nm band but was accompanied by nearly complete bleaching of the higher energy 240 nm band. Based on a Kramers-Kronig analysis of the absorption changes, refractive index changes on the order of {minus}10{sup {minus}2} are estimated. Confirmation of this calculation has been provided via ellipsometry which estimates a refractive index change at 632 nm of {minus}0.061 {+-} 0.002. Thus, the results of this investigation confirm the photosensitive potential of this type of material.

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

    SciTech Connect

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

    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.

  20. Room-temperature ferromagnetic and ferroelectric behavior in polycrystalline ZnO-based thin films

    NASA Astrophysics Data System (ADS)

    Lin, Yuan-Hua; Ying, Minghao; Li, Ming; Wang, Xiaohui; Nan, Ce-Wen

    2007-05-01

    Polycrystalline ZnO-based thin films with Li and/or Co doping have been prepared by a sol-gel spin-coating method on silicon substrates. Magnetization measurements reveal that Li-doped ZnO film shows paramagnetic behavior. However, the Co-doped ZnO thin films show obvious room-temperature ferromagnetic properties, and ferromagnetic properties can be enhanced by the Li codoping, which may be ascribed to indirect exchange via Li-related defects. All ZnO-based films exhibit ferroelectric behavior, and ferroelectric properties can be tuned by the dopants.

  1. Soil burial biodegradation studies of palm oil-based UV-curable films

    NASA Astrophysics Data System (ADS)

    Tajau, Rida; Salleh, Mek Zah; Salleh, Nik Ghazali Nik; Abdurahman, Mohamad Norahiman; Salih, Ashraf Mohammed; Fathy, Siti Farhana; Azman, Anis Asmi; Hamidi, Nur Amira

    2016-01-01

    The palm oil-based ultraviolet (uv)-curable films were subjected to an outdoor soil burial test to investigate the biodegradation under natural environment. The films were burial in the soil experiment plot at the Nuclear Malaysia's Dengkil complex. The uv-curable films were synthesized from the epoxidized palm oil acrylated (EPOLA) resin and the polyurethane palm oil (POBUA) resin, respectively. Biodegradation tests are more specific to burial film in soil experiments for 12 months under natural conditions. The biodegradability of palm oil resin based uv-curable films were investigated and compared with the petrochemical resin based film. The films properties were compared with respect to properties of the thermal characteristic, the crystallinity, the morphology and the weight loss which are analyzed using the thermogravimetric analysis (TGA), the differential scanning calorimetry (DSC), the scanning electron microscope (SEM), an optical microscope and the weight loss of film calculation. These findings suggested that the palm oil-based uv-curable films show quite satisfactory biodegradation levels.

  2. 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.

  3. Planting Healthy Roots: Using Documentary Film to Evaluate and Disseminate Community-Based Participatory Research.

    PubMed

    Brandt, Heather M; Freedman, Darcy A; Friedman, Daniela B; Choi, Seul Ki; Seel, Jessica S; Guest, M Aaron; Khang, Leepao

    2016-01-01

    Documentary filmmaking approaches incorporating community engagement and awareness raising strategies may be a promising approach to evaluate community-based participatory research. The study purpose was 2-fold: (1) to evaluate a documentary film featuring the formation and implementation of a farmers' market and (2) to assess whether the film affected awareness regarding food access issues in a food-desert community with high rates of obesity. The coalition model of filmmaking, a model consistent with a community-based participatory research (CBPR) approach, and personal stories, community profiles, and expert interviews were used to develop a documentary film (Planting Healthy Roots). The evaluation demonstrated high levels of approval and satisfaction with the film and CBPR essence of the film. The documentary film aligned with a CBPR approach to document, evaluate, and disseminate research processes and outcomes. PMID:27536929

  4. Reduced graphene oxide based silver sulfide hybrid films formed at a liquid/liquid interface

    SciTech Connect

    Bramhaiah, K. John, Neena S.

    2014-04-24

    Free-standing, ultra-thin films of silver sulfide and reduced graphene oxide (RGO) based silver sulfide hybrids are prepared at a liquid/liquid interface employing in situ chemical reaction strategy. Ag{sub 2}S and RGO−Ag{sub 2}S hybrid films are characterized by various techniques such as UV-visible and photo luminescence spectroscopy, X-ray diffraction and scanning electron microscopy. The morphology of hybrid films consists of Ag{sub 2}S nanocrystals on RGO surface while Ag{sub 2}S films contains branched network of dendritic structures. RGO−Ag{sub 2}S exhibit interesting optical and electrical properties. The hybrid films absorb in the region 500–650 nm and show emission in the red region. A higher conductance is observed for the hybrid films arising from the RGO component. This simple low cost method can be extended to prepare other RGO based metal sulfides.

  5. 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.

  6. 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

  7. Optical position detectors based on thin film amorphous silicon

    NASA Astrophysics Data System (ADS)

    Henry, Jasmine; Livingstone, John

    2001-10-01

    Thin film optical position sensitive detectors (PSDs) based on novel hydrogenated amorphous silicon Schottky barrier (SB) structures are compared in this work. The three structures reported here have been tested under different light sources to measure their linear properties and wavelength response characteristics. The sputtered a-Si sensors were configured as layered structures of platinum, a-Si and indium tin oxide, forming SB-i-n devices and exhibited linear properties similar to multi-layer a-Si p-i- n devices produced by complex chemical vapor deposition procedures, which involve flammable and toxic gases. All structures were test4ed as possible configurations for 2D sensors. The devices were tested under white light, filtered white light and also a red diode laser. Each of the three structures responded quite differently to each of the sources. Results, based on the correlation coefficient, which measures the linearity of output and which has a maximum value of 1, produced r values ranging between 0.992 to 0.999, in the best performances.

  8. Thin-film chemical sensors based on electron tunneling

    NASA Technical Reports Server (NTRS)

    Khanna, S. K.; Lambe, J.; Leduc, H. G.; Thakoor, A. P.

    1985-01-01

    The physical mechanisms underlying a novel chemical sensor based on electron tunneling in metal-insulator-metal (MIM) tunnel junctions were studied. Chemical sensors based on electron tunneling were shown to be sensitive to a variety of substances that include iodine, mercury, bismuth, ethylenedibromide, and ethylenedichloride. A sensitivity of 13 parts per billion of iodine dissolved in hexane was demonstrated. The physical mechanisms involved in the chemical sensitivity of these devices were determined to be the chemical alteration of the surface electronic structure of the top metal electrode in the MIM structure. In addition, electroreflectance spectroscopy (ERS) was studied as a complementary surface-sensitive technique. ERS was shown to be sensitive to both iodine and mercury. Electrolyte electroreflectance and solid-state MIM electroreflectance revealed qualitatively the same chemical response. A modified thin-film structure was also studied in which a chemically active layer was introduced at the top Metal-Insulator interface of the MIM devices. Cobalt phthalocyanine was used for the chemically active layer in this study. Devices modified in this way were shown to be sensitive to iodine and nitrogen dioxide. The chemical sensitivity of the modified structure was due to conductance changes in the active layer.

  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. High efficiency THz-wave modulators based on conjugated polymer-based organic films

    NASA Astrophysics Data System (ADS)

    He, Ting; Zhang, Bo; Wang, Guo-cui; Zang, Meng-di; Hou, Yan-bing; Shen, Jing-ling

    2016-02-01

    A study of the modulation mechanisms of conjugated polymer-based organic films and high-efficiency, broadband and all-optically controlled terahertz modulators based on these films is presented in this paper. Under very low-level external laser excitation, modulation efficiency of more than 99% is achieved using MEH-PPV/Si, PFO/Si and F8BT/Si bilayers. By analyzing the changes in the photo-excited carrier density and photoconductivity with changes in the external laser intensity, we introduce a nonlinear photo-induced absorption process to explain the strong attenuation mechanism for the transmitted terahertz waves. Finally, a simple THz communication test is carried out to demonstrate the potential future applications of the high-efficiency all-optically controlled terahertz modulator.

  11. 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

  12. 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

  13. Structural studies on drop-cast film based on functionalized gold nanoparticles network: The effect of thermal treatment

    NASA Astrophysics Data System (ADS)

    Fontana, Laura; Fratoddi, Ilaria; Venditti, Iole; Ksenzov, Dmitriy; Russo, Maria Vittoria; Grigorian, Souren

    2016-04-01

    In the present work the role of the thermal treatment on the reorganization of gold nanoparticles (AuNPs) functionalized with a π-conjugated dithiol ligand, namely 9,9-didodecyl-2,7-bis-thiofluorene, is studied by grazing incidence X-ray diffraction technique. For a detailed investigation of the structural changes and reorganization occurring in the AuNPs network and of the monitoring of complex interactions between nanoparticles, the line profiles are analyzed in out-of-plane and in-plane directions. The obtained data support the idea of the formation of a uniform network of nanoparticles that after annealing are extended from hexagonal to cubic arrangement.

  14. STARCH/PULP-FIBER BASED PACKAGING FOAMS AND CAST FILMS CONTAINING ALASKAN FISH BY-PRODUCTS (WASTE)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Baked starch/pulp foams were prepared from formulations containing 0-25% (wt%) of processed Alaskan fish by-products that consisted mostly of salmon heads, pollock heads and pollock frames (bones and associated remains produced in the filleting operation). Fish by-products thermoformed well along wi...

  15. 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

  16. CASTING METHOD AND APPARATUS

    DOEpatents

    Gray, C.F.; Thompson, R.H.

    1958-10-01

    An improved apparatus for the melting and casting of uranium is described. A vacuum chamber is positioned over the casting mold and connected thereto, and a rod to pierce the oxide skin of the molten uranium is fitted into the bottom of the melting chamber. The entire apparatus is surrounded by a jacket, and operations are conducted under a vacuum. The improvement in this apparatus lies in the fact that the top of the melting chamber is fitted with a plunger which allows squeezing of the oxide skin to force out any molten uranium remaining after the skin has been broken and the molten charge has been cast.

  17. CENTRIFUGAL CASTING MACHINE

    DOEpatents

    Shuck, A.B.

    1958-04-01

    A device is described that is specifically designed to cast uraniumn fuel rods in a vacuunn, in order to obtain flawless, nonoxidized castings which subsequently require a maximum of machining or wastage of the expensive processed material. A chamber surrounded with heating elements is connected to the molds, and the entire apparatus is housed in an airtight container. A charge of uranium is placed in the chamber, heated, then is allowed to flow into the molds While being rotated. Water circulating through passages in the molds chills the casting to form a fine grained fuel rod in nearly finished form.

  18. 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

  19. Elastohydrodynamic film thickness formula based on X-ray measurements with a synthetic paraffinic oil

    NASA Technical Reports Server (NTRS)

    Loewenthal, S. H.; Parker, R. J.; Zaretsky, E. V.

    1973-01-01

    An empirical elastohydrodynamic film thickness formula for heavily loaded contacts based upon X-ray film thickness measurements made with a synthetic paraffinic oil is presented. The deduced relation was found to adequately reflect the high load dependence exhibited by the measured minimum film thickness data at high Hertizian contact stresses, that is, above 1.04 x 10 to the ninth N/sq m (150,000 psi). Comparisons were made with the numerical results from a theoretical isothermal film thickness formula. The effects of changes in contact geometry, material, and lubricant properties on the form of the empirical model are also discussed.

  20. Thickness microscopy based on photothermal radiometry for the measurement of thin films.

    PubMed

    Wang, Liping; Prekel, Helmut; Liu, Hengbiao; Deng, Yanzhuo; Hu, Jiming; Goch, Gert

    2009-03-01

    The photothermal detection technique is an innovative and non-contact method to investigate the properties of films on workpieces. This paper describes a novel experimental set-up for thickness microscopy based on photothermal radiometry. The correlation between the thermal wave signal and the film thickness is deduced and evaluated to determine the film thickness with a lateral resolution of less than 1mm. Results indicate that the thickness microscopy is a useful method to characterize thin films and has the potential to be applied in-process. PMID:19046925

  1. AFM and XPA data on structural features and properties of films and powders based on naphthalocyanines

    NASA Astrophysics Data System (ADS)

    Ramonova, A. G.; Nakusov, A. T.; Sozanov, V. G.; Bliev, A. P.; Magkoev, T. T.

    2015-06-01

    The template synthesis is used to produce powders and films based on naphthalocyanines and the corresponding metal complexes (Pc, CuPc, and NiPc). The atomic-force microscopy (AFM) and X-ray phase analysis (XPA) are employed in the study of structure and phase of fine powders and nanostructured films. The AFM data are used to determine the orientation and density of primary particles packed in the film. The XPA method is used to study the chemical composition and crystal structure of the synthesized samples. The regularities related to the structural features that affect the electrophysical properties of the films under study are revealed.

  2. Versatile Method for Coating Surfaces with Functional and Responsive Polymer-Based Films.

    PubMed

    Zhang, Qiang Matthew; Serpe, Michael J

    2015-12-16

    A versatile surface modification technique was developed to yield poly(N-isopropylacrylamide) (pNIPAm) microgel-based thin films on a variety of substrates, e.g., metals, nonmetals, and polymers. Because the chemistry, and hence functionality and responsivity, of the pNIPAm-based microgels is easily tuned, multifunctional and responsive thin films could be generated on many different surfaces without varying the coating conditions. In one case, we showed that fluorescent/light emitting thin films could be generated using crystal violet-modified microgels. Antibacterial films could be obtained using silver nanoparticle-modified pNIPAm-based microgels. Finally, we show that thin films fabricated via the methods here could be used as a component in optical sensors. Although we show only a few examples of the utility of this approach, we feel that the apparent universality of the technique can be extended to countless other applications. PMID:26640982

  3. 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.

  4. 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.

  5. Tunneling Nanoelectromechanical Switches Based on Compressible Molecular Thin Films.

    PubMed

    Niroui, Farnaz; Wang, Annie I; Sletten, Ellen M; Song, Yi; Kong, Jing; Yablonovitch, Eli; Swager, Timothy M; Lang, Jeffrey H; Bulović, Vladimir

    2015-08-25

    Abrupt switching behavior and near-zero leakage current of nanoelectromechanical (NEM) switches are advantageous properties through which NEMs can outperform conventional semiconductor electrical switches. To date, however, typical NEMs structures require high actuation voltages and can prematurely fail through permanent adhesion (defined as stiction) of device components. To overcome these challenges, in the present work we propose a NEM switch, termed a "squitch," which is designed to electromechanically modulate the tunneling current through a nanometer-scale gap defined by an organic molecular film sandwiched between two electrodes. When voltage is applied across the electrodes, the generated electrostatic force compresses the sandwiched molecular layer, thereby reducing the tunneling gap and causing an exponential increase in the current through the device. The presence of the molecular layer avoids direct contact of the electrodes during the switching process. Furthermore, as the layer is compressed, the increasing surface adhesion forces are balanced by the elastic restoring force of the deformed molecules which can promote zero net stiction and recoverable switching. Through numerical analysis, we demonstrate the potential of optimizing squitch design to enable large on-off ratios beyond 6 orders of magnitude with operation in the sub-1 V regime and with nanoseconds switching times. Our preliminary experimental results based on metal-molecule-graphene devices suggest the feasibility of the proposed tunneling switching mechanism. With optimization of device design and material engineering, squitches can give rise to a broad range of low-power electronic applications. PMID:26244821

  6. Hysteresis in pentacene-based organic thin-film transistors

    NASA Astrophysics Data System (ADS)

    Gu, Gong; Kane, Michael G.

    2006-08-01

    Memory effects are commonly seen in organic thin-film transistor (OTFT) characteristics. In the absence of memory effects associated with the gate dielectric, the hysteresis in p-channel pentacene-based OTFTs, as measured in air and under illumination, was found to be dominated by trapped electrons, rather than trapped holes, in the semiconductor. The responsible acceptor type traps have very long lifetime. The immobile, previously stored negative charge requires extra holes to balance it, resulting in early establishment of the channel and extra drain current. This model is unique in that it discusses the majority carrier population influenced by trapped charge opposite in sign to the majority carriers in a simple electrostatic manner, to explain history dependence. The model was supported by drain current transient decay data. This memory effect is ambient and illumination sensitive. We studied the presence or absence of this effect under various ambient and illumination conditions, and found the responsible acceptor type traps mostly extrinsic and their formation reversible. Efforts were taken in the quantitative analysis to exclude the bias stress effect from the memory effect due to the charged acceptors.

  7. 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.

  8. Potential of Kaolin-based Particle Film Barriers for Formosan Subterranean Termite (Isoptera: Rhinotermitidae) Control

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Effects of three particle film products on Formosan subterranean termites, Coptotermes formosanus Shiraki, were evaluated in feeding, tunneling, and contact assays. The particle films, hydrophobic M96-018 and hydrophilic Surround and Surround WP are based on the inert clay mineral kaolin. In 2-week ...

  9. Structure and physicochemical properties of thin film photosemiconductor cells based on porphine derivatives

    NASA Astrophysics Data System (ADS)

    Kazak, A. V.; Usol'tseva, N. V.; Smirnova, A. I.; Bodnarchuk, V. V.; Sul'yanov, S. N.; Yablonskii, S. V.

    2016-05-01

    Photosemiconductor thin films based on two organic porphine derivatives have been investigated. These compounds have different pendent groups; the film morphology, along with the specific fabrication technique, is determined to a great extent by these groups. The films have been fabricated by vacuum sputtering and using the Langmuir-Schaefer method. According to the atomic force microscopy (AFM) data, the Langmuir-Schaefer films are more homogeneous than the sputtered ones. It is shown that the sputtered films based on substituted porphine have a looser stacking than the initial analog. A spectroscopy study revealed a bathochromic shift of the Soret band in the Langmuir-Schaefer films-sputtered films series. This shift is explained by the increase in the concentration and size of molecular aggregates in sputtered films. It is shown that a polycrystalline C60 fullerene film deposited onto an amorphous substituted porphine layer improves the photoelectric characteristics of the latter. Both the time stability of the photodiode structure and its ampere‒watt sensitivity increase (by a factor of 10 in the transition regime). The steady-state current does not change. The effect of polarity reversal of the photovoltaic signal is observed in a planar C60‒substituted metalloporphine heterostructure, which is similar to the pyroelectric effect. The polarity reversal can be explained by the contribution of the trap charge and discharge current at the interface between the amorphous photosemiconductor and crystalline photosemiconductor to the resulting photoelectric current.

  10. Roll Casting of Aluminum Alloy Clad Strip

    SciTech Connect

    Nakamura, R.; Tsuge, H.; Haga, T.; Watari, H.; Kumai, S.

    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.

  11. 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 μm 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.

  12. 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

  13. Controlling coverage of solution cast materials with unfavourable surface interactions

    NASA Astrophysics Data System (ADS)

    Burlakov, V. M.; Eperon, G. E.; Snaith, H. J.; Chapman, S. J.; Goriely, A.

    2014-03-01

    Creating uniform coatings of a solution-cast material is of central importance to a broad range of applications. Here, a robust and generic theoretical framework for calculating surface coverage by a solid film of material de-wetting a substrate is presented. Using experimental data from semiconductor thin films as an example, we calculate surface coverage for a wide range of annealing temperatures and film thicknesses. The model generally predicts that for each value of the annealing temperature there is a range of film thicknesses leading to poor surface coverage. The model accurately reproduces solution-cast thin film coverage for organometal halide perovskites, key modern photovoltaic materials, and identifies processing windows for both high and low levels of surface coverage.

  14. Mathematical Modeling of Surface Roughness of Castings Produced Using ZCast Direct Metal Casting

    NASA Astrophysics Data System (ADS)

    Chhabra, M.; Singh, R.

    2015-04-01

    Aim of this investigation is to develop a mathematical model for predicting surface roughness of castings produced using ZCast process by employing Buckingham's π-theorem. A relationship has been proposed between surface roughness of castings and shell wall thickness of the shell moulds fabricated using 3D printer. Based on model, experiments were performed to obtain the surface roughness of aluminium, brass and copper castings produced using ZCast process based on 3D printing technique. Based on experimental data, three best fitted third-degree polynomial equations have been established for predicting the surface roughness of castings. The predicted surface roughness values were then calculated using established best fitted equations. An error analysis was performed to compare the experimental and predicted data. The average prediction errors obtained for aluminium, brass and copper castings are 10.6, 2.43 and 3.12 % respectively. The obtained average surface roughness (experimental and predicted) values of castings produced are acceptable with the sand cast surface roughness values range (6.25-25 µm).

  15. Transparent and conductive electrodes based on unpatterned, thin metal films

    NASA Astrophysics Data System (ADS)

    O'Connor, Brendan; Haughn, Chelsea; An, Kwang-Hyup; Pipe, Kevin P.; Shtein, Max

    2008-12-01

    Transparent electrodes composed of ultrathin, unpatterned metal films are investigated in planar heterojunction (PHJ) and bulk heterojunction organic photovoltaic (OPV) cells. Optimal electrode composition and thickness are deduced from electrical and optical models and experiments, enabling a PHJ-OPV cell to be realized using a silver anode, achieving power conversion efficiency parity with an analogous cell that uses an indium tin oxide anode. Beneficial aspects of smooth, unpatterned metal films as transparent electrodes in OPV cells are also discussed in the text.

  16. Method of casting aerogels

    DOEpatents

    Poco, J.F.

    1993-09-07

    The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm[sup 3] to 0.6 g/cm[sup 3]. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of aerogel which occurs during the drying step of supercritical extraction of solvent. 2 figures.

  17. Method of casting aerogels

    DOEpatents

    Poco, John F.

    1993-01-01

    The invention describes a method for making monolithic castings of transparent silica aerogel with densities in the range from 0.001 g/cm.sup.3 to 0.6 g/cm.sup.3. Various shapes of aerogels are cast in flexible polymer molds which facilitate removal and eliminate irregular surfaces. Mold dimensions are preselected to account for shrinkage of alcogel which occurs during the drying step of supercritical extraction of solvent.

  18. LiMn2O4-based cathode thin films for Li thin-film batteries

    NASA Astrophysics Data System (ADS)

    Yim, Haena; Shin, Dong-Wook; Choi, Ji-Won

    2016-01-01

    Substitution methods for Mn3+ in a spinel lithium manganese oxide with other cations have been used to prevent capacity degradation during the electrochemical charge and discharge of Li-batteries by increasing the average valence of Mn. In particular, in this review we outlin the effects of Sn substitution on the cycling performance of LiMn2O4 thin films that can be used as positive electrode in Li-batteries. The thin films were prepared by using pulsed laser deposition and solution deposition with regard to the structural and the electro-chemical characteristics.

  19. 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.

  20. Design of camouflage material for visible and near infrared based on thin film technology

    NASA Astrophysics Data System (ADS)

    Miao, Lei; Shi, Jia-ming; Zhao, Da-peng; Liu, Hao; Wang, Chao; Xu, Yan-liang

    2015-11-01

    Visible light and near infrared based camouflage materials achieve good stealth under traditional optical detection equipment but its spectral differences with green plants can be taken advantage of by high spectrum based detection technologies. Based on the thin structure of bandpass filter, we designed an optical film with both green and near infrared spectrum. We conducted simulations using transfer matrix methods and optimized the result by simplex methods. The spectral reflectance curve of the proposed thin film matches that of green plants, and experiments show that the proposed thin film achieve good invisibility under visible light and near infrared in a wide viewing angle.

  1. Edible antimicrobial films based on microencapsulated lemongrass oil.

    PubMed

    Bustos C, Rubén O; Alberti R, Francesca V; Matiacevich, Silvia B

    2016-01-01

    Edible films and coatings have been proposed as viable alternatives for the preservation of fresh food such as fruit, meat, fish and cheese. They can be designed to contain natural antioxidants, vitamins and antimicrobials in order to extend shelf life of the product keeping the natural sensorial properties. Essential oils have been targeted as potential active principles for edible films and coatings given their well-recognized antioxidant, antimicrobial and sensory properties. In the present work, lemongrass oil (LMO) microcapsules were prepared by the emulsification-separation method using sodium caseinate as wall material. Microcapsules had an average size of 22 μm and contained over 51 % oil in their nucleus. The release kinetics of the LMO components was studied for both, microcapsules and microcapsule containing films. Experimental data for the controlled release of LMO components showed good correlation with Peppas and Weibull models. The effect of the alginate matrix on the release parameters of the mathematical models could be detected by the modification of the b constant of the Weibull equation which changed from 0.167 for the microcapsules to 0.351 for the films. Films containing LMO at concentrations of 1250, 2500 and 5000 ppm were able to inhibit growth of Escherichia coli ATCC 25922 and Listeria monocytogenes ISP 65-08 in liquid cultures. A possible future application of these films for shelf life extension of fresh food is discussed. PMID:26788005

  2. Predicting Pattern Tooling and Casting Dimensions for Investment Casting - Phase II

    SciTech Connect

    Sabau, Adrian S

    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

  3. (Continuous casting 1985)

    SciTech Connect

    Wilde, R.A.

    1985-06-12

    The report covers the Continuous Casting '85 Conference including informal discussions with conference attendees. In general, the papers presented at the conference concerned an overview of continuous steel casting worldwide, state-of-the-art aspects of steel continuous casting technology including caster startup problems, modifications, control system strategies, energy use profiles, quality control aspects, steel chemistry control, refractories, operational aspects of continuous casters, etc. No papers were presented in the development of thin section or thin strip casting of steel. Informal discussions were held with several conference attendees including (1) Bernard Trentini, Executive Director of the Association Technique De La Siderurgie Francaise in Paris, France (similar to the American Iron and Steel Institute); (2) Dr. Wolfgang Reichelt and Dr. Peter Voss-Spilker both of Mannesmann Demag Huttentechnik -a continuous casting and other steel making machine builder in-lieu of meeting at their plant in Duisburg, FRG on May 31; (3) Ewan C. Hewitt of Devote McKee Corp., Sheffield, England; (4) Wilfried Heinemann, head of R D Dept. at Concast Standard AG in Zurich, Switzerland; and (5) Hideo Ueno, engineer of melting section, Mitsubishi Steel Mfg. Co. Ltd, Tokyo Japan. A visit was made to the Teesside Laboratories of British Steel Corp. for discussions of their thin section casting research program in particular and R D program in general.

  4. Salvaged castings and methods of salvaging castings with defective cast cooling bumps

    DOEpatents

    Johnson, Robert Alan; Schaeffer, Jon Conrad; Lee, Ching-Pang; Abuaf, Nesim; Hasz, Wayne Charles

    2002-01-01

    Castings for gas turbine parts exposed on one side to a high-temperature fluid medium have cast-in bumps on an opposite cooling surface side to enhance heat transfer. Areas on the cooling surface having defectively cast bumps, i.e., missing or partially formed bumps during casting, are coated with a braze alloy and cooling enhancement material to salvage the part.

  5. High performance NH 3 gas sensor based on ordered conducting polymer ultrathin film

    NASA Astrophysics Data System (ADS)

    Xu, Jianhua; Jiang, Yadong; Yu, Junsheng; Yang, Yajie; Ying, Zhihua

    2008-02-01

    Conducting polymer ultrathin film shows promising future for gas sensor application due to their high conductivity and excellent doping/dedoping performance. In this work, based on an modified Langmuir-Blodgett film method, ultrathin conducting poly(3,4-ethylene dioxythiophene) (PEDOT) film was fabricated. The PEDOT ultathin film was characterized by UV-Vis absorption spectrum, X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM) techniques. The results showed small PEDOT grains distributed in polymer LB films after the polymerization of monomer. This ultrathin film exhibited an electrical conductivity about 1.2 Scm -1, and the conductivity increased and decreased to 16.8 and 0.03 Scm -1 after doping and dedoping treatment. The interaction or response of films coated QCM to NH 3 have been tested and it has been found that sensitivity of the composite films on QCM showed better sensitivity than bulk material. To the same analyte concentration, it increased with the increasing number of LB layers coated onto QCMS before 80 layers, and then a decrease of sensitivity of QCM was observed after the layer number exceeded 80 layers. The interaction mechanisms between the ultrathin film and analyte vapor were also included.

  6. 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

    2015-01-01

    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

  7. Influence of hydroxypropylmethylcellulose addition and homogenization conditions on properties and ageing of corn starch based films.

    PubMed

    Jiménez, Alberto; Fabra, María José; Talens, Pau; Chiralt, Amparo

    2012-06-20

    Edible films based on corn starch, hydroxypropyl methylcellulose (HPMC) and their mixtures were prepared by using two different procedures to homogenize the film forming dispersions (rotor-stator and rotor-stator plus microfluidizer). The influence of both HPMC-starch ratio and the homogenization method on the structural, optical, tensile and barrier properties of the films was analysed. The ageing of the films was also studied by characterizing them after 5 weeks' storage. Starch re-crystallization in newly prepared and stored films was analysed by means of X-ray diffraction. HPMC-corn starch films showed phase separation of polymers, which was enhanced when microfluidization was applied to the film forming dispersion. Nevertheless, HPMC addition inhibited starch re-crystallization during storage, giving rise to more flexible films at the end of the period. Water barrier properties of starch films were hardly affected by the addition of HPMC, although oxygen permeability increased due to its poorer oxygen barrier properties. PMID:24750773

  8. 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

  9. Oxide-based method of making compound semiconductor films and making related electronic devices

    DOEpatents

    Kapur, Vijay K.; Basol, Bulent M.; Leidholm, Craig R.; Roe, Robert A.

    2000-01-01

    A method for forming a compound film includes the steps of preparing a source material, depositing the source material on a base and forming a preparatory film from the source material, heating the preparatory film in a suitable atmosphere to form a precursor film, and providing suitable material to said precursor film to form the compound film. The source material includes oxide-containing particles including Group IB and IIIA elements. The precursor film includes non-oxide Group IB and IIIA elements. The compound film includes a Group IB-IIIA-VIA compound. The oxides may constitute greater than about 95 molar percent of the Group IB elements and greater than about 95 molar percent of the Group IIIA elements in the source material. Similarly, non-oxides may constitute greater than about 95 molar percent of the Group IB elements and greater than about 95 molar percent of the Group IIIA elements in the precursor film. The molar ratio of Group IB to Group IIIA elements in the source material may be greater than about 0.6 and less than about 1.0, or substantially greater that 1.0, in which case this ratio in the compound film may be reduced to greater than about 0.6 and less than about 1.0. The source material may be prepared as an ink from particles in powder form. The oxide-containing particles may include a dopant, as may the compound film. Compound films including a Group IIB-IVA-VA compound may be substituted using appropriate substitutions in the method. The method, also, is applicable to fabrication of solar cells and other electronic devices.

  10. Optically active multilayer films based on chitosan and an azopolymer.

    PubMed

    Fernández, Raquel; Ocando, Connie; Fernandes, Susana C M; Eceiza, Arantxa; Tercjak, Agnieszka

    2014-04-14

    The layer-by-layer technique has been widely adopted for the fabrication of nanostructures with tailored properties. In this work, photoactive multilayer films consisting of alternating layers of chitosan and an azopolymer were developed by this method. Taking into account that pH is the factor controlling the charge of weak polyelectrolytes, the influence of this parameter on the structure and properties of the multilayer films was evaluated. Thus, different films were prepared by varying pH conditions as well as bilayer number. The morphology and properties of the films were analyzed by diverse advanced techniques, such as ultraviolet-visible spectroscopy, X-ray diffraction, and atomic force microscopy equipped with PeakForce QNM (Quantitative Nanomechanical Property Mapping). It was found that the thickness, roughness and elastic modulus of the developed multilayer films increased with the decrease of the chitosan solution pH and the increase of the bilayer number. Furthermore, induced birefringence measurements revealed that a higher level of photo-orientation was attained with the decrease of pH and the increase of bilayer number. PMID:24564819

  11. Magnetic Fe-Co films electroplated in a deep-eutectic-solvent-based plating bath

    NASA Astrophysics Data System (ADS)

    Yanai, T.; Shiraishi, K.; Watanabe, Y.; Ohgai, T.; Nakano, M.; Suzuki, K.; Fukunaga, H.

    2015-05-01

    We fabricated Fe-Co films from a deep eutectic solvent (DES)-based plating bath and investigated magnetic properties of the plated films. The plating baths were obtained by stirring the mixture of choline chloride, ethylene glycol, FeCl2.4H2O, and CoCl2.6H2O. The composition of the plated films depended on the amount of FeCl2.4H2O in the plating bath, and Fe content of the films was varied from 0 to 100 at. %. Depending on the Fe content, the saturation magnetization and the coercivity of the films varied. The Fe76Co24 film shows high saturation magnetization and smooth surface, and the change in the saturation magnetization shows good agreement with the expected change by the Slater-Pauling curve. High current efficiency (>90%) could be obtained in the wide film composition. From these results, we concluded that the DES-based plating bath is one of effective baths for the Fe-Co films with high current efficiency.

  12. Titan Casts Revealing Shadow

    NASA Astrophysics Data System (ADS)

    2004-05-01

    A rare celestial event was captured by NASA's Chandra X-ray Observatory as Titan -- Saturn's largest moon and the only moon in the Solar System with a thick atmosphere -- crossed in front of the X-ray bright Crab Nebula. The X-ray shadow cast by Titan allowed astronomers to make the first X-ray measurement of the extent of its atmosphere. On January 5, 2003, Titan transited the Crab Nebula, the remnant of a supernova explosion that was observed to occur in the year 1054. Although Saturn and Titan pass within a few degrees of the Crab Nebula every 30 years, they rarely pass directly in front of it. "This may have been the first transit of the Crab Nebula by Titan since the birth of the Crab Nebula," said Koji Mori of Pennsylvania State University in University Park, and lead author on an Astrophysical Journal paper describing these results. "The next similar conjunction will take place in the year 2267, so this was truly a once in a lifetime event." Animation of Titan's Shadow on Crab Nebula Animation of Titan's Shadow on Crab Nebula Chandra's observation revealed that the diameter of the X-ray shadow cast by Titan was larger than the diameter of its solid surface. The difference in diameters gives a measurement of about 550 miles (880 kilometers) for the height of the X-ray absorbing region of Titan's atmosphere. The extent of the upper atmosphere is consistent with, or slightly (10-15%) larger, than that implied by Voyager I observations made at radio, infrared, and ultraviolet wavelengths in 1980. "Saturn was about 5% closer to the Sun in 2003, so increased solar heating of Titan may account for some of this atmospheric expansion," said Hiroshi Tsunemi of Osaka University in Japan, one of the coauthors on the paper. The X-ray brightness and extent of the Crab Nebula made it possible to study the tiny X-ray shadow cast by Titan during its transit. By using Chandra to precisely track Titan's position, astronomers were able to measure a shadow one arcsecond in

  13. Steel castings by the electroslag casting technique. [CF8M

    SciTech Connect

    Sikka, V.K.; Mitchell, A.

    1984-01-01

    ELectroslag casting facilities in Canada and the United States were reviewed. Several valve body castings of 2-1/4 Cr-1 Mo, 9 Cr-1 Mo, and 18% Cr-8% Ni(Mo) steels were made at the University of British Columbia facility. These castings were examined for surface finish, chemical segregation, and macrostructure in the as-cast condition and after various heat treatments. Castings were subjected to tensile, Charpy impact, and creep testing. Results of these tests were compared with similar data on wrought material and sand castings.

  14. 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.

  15. 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

  16. FILMING OF 'CONTACT' AT LC39 PRESS SITE

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Warner Bros.' cast and crew are filming scenes for the movie 'Contact' at Kennedy Space Center's Launch Complex 39 Press Site on January 30. The screenplay for 'Contact' is based on the best- selling novel by the late astronomer Carl Sagan. The cast includes Jodie Foster, Matthew McConaughey, John Hurt, James Woods, Tom Skerritt, David Morse, William Fichtner, Rob Lowe and Angela Bassett. Described by Warner Bros. as a science fiction drama, 'Contact' will depict humankind's first encounter with evidence of extraterrestrial life.

  17. FILMING OF 'CONTACT' AT LC39 PRESS SITE

    NASA Technical Reports Server (NTRS)

    1997-01-01

    Warner Bros.' cast and crew are filming scenes for the movie 'Contact' at Kennedy Space Center's Launch Complex 39 Press Site on January 29. The screenplay for 'Contact' is based on the best- selling novel by the late astronomer Carl Sagan. The cast includes Jodie Foster, Matthew McConaughey, John Hurt, James Woods, Tom Skerritt, David Morse, William Fichtner, Rob Lowe and Angela Bassett. Described by Warner Bros. as a science fiction drama, 'Contact' will depict humankind's first encounter with evidence of extraterrestrial life.

  18. Thermal conductivity and mechanical properties of AlN-based thin films

    NASA Astrophysics Data System (ADS)

    Moraes, V.; Riedl, H.; Rachbauer, R.; Kolozsvári, S.; Ikeda, M.; Prochaska, L.; Paschen, S.; Mayrhofer, P. H.

    2016-06-01

    While many research activities concentrate on mechanical properties and thermal stabilities of protective thin films, only little is known about their thermal properties being essential for the thermal management in various industrial applications. Based on the 3ω-method, we show the influence of Al and Cr on the temperature dependent thermal conductivity of single-phase cubic structured TiN and single-phase wurtzite structured AlN thin films, respectively, and compare them with the results obtained for CrN thin films. The dc sputtered AlN thin films revealed a highly c-axis oriented growth for deposition temperatures of 250 to 700 °C. Their thermal conductivity was found to increase strongly with the film thickness, indicating progressing crystallization of the interface near amorphous regions during the sputtering process. For the 940 nm AlN film, we found a lower boundary for the thermal conductivity of 55.3 W m-1 K-1 . By the substitution of only 10 at. % Al with Cr, κ significantly reduces to ˜5.0 W m-1 K-1 , although the single-phase wurtzite structure is maintained. The single-phase face centered cubic TiN and Ti0.36Al0.64N thin films exhibit κ values of 3.1 W m-1 K-1 and 2.5 W m-1 K-1 , respectively, at room temperature. Hence, also here, the substitutional alloying reduces the thermal conductivity, although at a significantly lower level. Single-phase face centered cubic CrN thin films show κ values of 3.6 W m-1 K-1 . For all nitride based thin films investigated, the thermal conductivity slightly increases with increasing temperature between 200 and 330 K. This rather unusual behavior is based on the high defect density (especially point defects) within the thin films prepared by physical vapor deposition.

  19. Optimizing the optical and electrical properties of graphene ink thin films by laser-annealing

    NASA Astrophysics Data System (ADS)

    Khandan Del, Sepideh; Bornemann, Rainer; Bablich, Andreas; Schäfer-Eberwein, Heiko; Li, Jiantong; Kowald, Torsten; Östling, Mikael; Haring Bolívar, Peter; Lemme, Max C.

    2015-03-01

    We demonstrate a facile fabrication technique for graphene-based transparent conductive films. Highly flat and uniform graphene films are obtained through the incorporation of an efficient laser annealing technique with one-time drop casting of high-concentration graphene ink. The resulting thin films are uniform and exhibit a transparency of more than 85% at 550 nm and a sheet resistance of about 30 kΩ/□. These values constitute an increase of 45% in transparency, a reduction of surface roughness by a factor of four and a decrease of 70% in sheet resistance compared to un-annealed films.

  20. Charge carrier transport in polycrystalline organic thin film based field effect transistors

    NASA Astrophysics Data System (ADS)

    Rani, Varsha; Sharma, Akanksha; Ghosh, Subhasis

    2016-05-01

    The charge carrier transport mechanism in polycrystalline thin film based organic field effect transistors (OFETs) has been explained using two competing models, multiple trapping and releases (MTR) model and percolation model. It has been shown that MTR model is most suitable for explaining charge carrier transport in grainy polycrystalline organic thin films. The energetic distribution of traps determined independently using Mayer-Neldel rule (MNR) is in excellent agreement with the values obtained by MTR model for copper phthalocyanine and pentacene based OFETs.

  1. Experimental Evaluation of Biodegradable Film Compositions Based on Gelatin with Colchicine.

    PubMed

    Bokeriya, L A; Bokeriya, O L; Sivtsev, V S; Novikova, S P; Salokhedinova, R R; Nikolashina, L N; Samsonova, N N; Gorodkov, A Yu; Serov, R A

    2016-07-01

    Biodegradable film compositions based on natural biopolymer gelatin with immobilized colchicine were prepared and their efficiency in prevention of the adhesion process in the pericardium was evaluated on rabbit model of postoperative pericarditis. The use of gelatin-based biodegradable film compositions significantly reduced the intensity of adhesion formation in the pericardial cavity, while immobilization of anti-inflammatory drug colchicine amplified their anti-adhesion activity. PMID:27496036

  2. A Naphthalenediimide-Based Metal-Organic Framework and Thin Film Exhibiting Photochromic and Electrochromic Properties.

    PubMed

    Xie, Yi-Xin; Zhao, Wen-Na; Li, Guo-Chang; Liu, Peng-Fei; Han, Lei

    2016-01-19

    A multifunctional metal-organic framework, NBU-3, has been explored as a 2D three-connected network based on a naphthalenediimide-based ligand. The NBU-3 crystals display photochromic properties, and NBU-3 thin films on FTO substrates exhibit electrochromic properties. NBU-3 is the first example of MOF materials containing both photochromic and electrochromic properties, which can be desirable for thin film devices. PMID:26713454

  3. Physical properties of emulsion-based hydroxypropyl methylcellulose films: effect of their microstructure.

    PubMed

    Zúñiga, R N; Skurtys, O; Osorio, F; Aguilera, J M; Pedreschi, F

    2012-10-01

    The initial characteristics of emulsions and the rearrangement of the oil droplets in the film matrix during film drying, which defines its microstructure, has an important role in the physical properties of the emulsion-based films. The objective of this work was to study the effect of the microstructure (two droplet size distributions) and stability (with or without surfactant) of HPMC oil-in-water emulsions over physical properties of HPMC emulsion-based edible films. HPMC was used to prepare sunflower oil-in-water emulsions containing 0.3 or 1.0% (w/w) of oil with or without SDS, as surfactant, using an ultrasonic homogenizer. Microstructure, rheological properties and stability of emulsions (creaming) were measured. In addition, microstructure, coalescence of oil droplets, surface free energy, optical and mechanical properties and water vapor transfer of HPMC films were evaluated. Image analysis did not show differences among droplet size distributions of emulsions prepared at different oil contents; however, by using SDS the droplet size distributions were shifted to lower values. Volume mean diameters were 3.79 and 3.77 μm for emulsions containing 0.3 and 1.0% without surfactant, respectively, and 2.72 and 2.71 μm for emulsions with SDS. Emulsions formulated with 1.0% of oil presented higher stability, with almost no change during 5 and 3 days of storage, for emulsions with and without SDS, respectively. Internal and surface microstructure of emulsion-based films was influenced by the degree of coalescence and creaming of the oil droplets. No effect of microstructure over the surface free energy of films was found. The incorporation of oil impaired the optical properties of films due to light scattering of light. Addition of oil and SDS decreased the stress at break of the emulsion-based films. The replace of HPMC by oil and SDS produce a lower "amount" of network structure in the films, leading to a weakening of their structure. The oil content and SDS

  4. Modeling the mechanics of graphene-based polymer composite film measured by the bulge test

    NASA Astrophysics Data System (ADS)

    Zhang, Jian-Jun; Sun, You-yi; Li, Dian-sen; Cao, Yang; Wang, Zuo; Ma, Jing; Zhao, Gui-Zhe

    2015-10-01

    Graphene-based polymer composite films have wide-ranging potential applications, such as in sensors, electromagnetic shielding, absorbing materials, corrosion resistance and so on. In addition, the practical applications of graphene-based polymer composite films are closely related to their mechanical properties. However, the mechanical properties of graphene-based polymer composite films are difficult to characterize with tensile tests. In this paper, the bugle test was used to investigate the mechanical properties of graphene-based polymer composite films. The experimental results show that the Young’s modulus of polymer composite films increases non-linearly with an increase in the doping content of graphene, and viscoelastic deformation is induced under cyclic loading conditions. Moreover, in order to describe their mechanical behavior, an ‘Arruda-Boyce’ finite-strain constitutive model (modified BPA model), based on the strain amplification hypothesis, and a traditional ‘Arruda-Boyce’ model was proposed, which incorporated many of the features of previous theories. The numerical treatment of the modified BPA model associated with finite element analysis is also discussed. This new model is shown to be able to predict the experimentally observed mechanical behavior of graphene based polymer composite films measured by the bugle test effectively.

  5. Stress Relaxation in Sn-Based Films: Effects of Pb Alloying, Grain Size, and Microstructure

    NASA Astrophysics Data System (ADS)

    Jadhav, Nitin; Wasserman, Jacob; Pei, Fei; Chason, Eric

    2012-03-01

    Stress is believed to provide the driving force for growth of Sn whiskers, so stress relaxation in the Sn layer plays a key role in their formation. To understand and enhance stress relaxation in Sn-based films, the effects of Pb alloying and microstructure on their mechanical properties have been studied by observing the relaxation of thermal expansion-induced strain. The relaxation rate is found to increase with film thickness and grain size in pure Sn films, and it depends on the microstructure in Pb-alloyed Sn films. Measurements of multilayered structures (Sn on Pb-Sn and Pb-Sn on Sn) show that changing the surface layer alone is not sufficient to enhance the relaxation, indicating that the Pb enhances relaxation in the bulk of the film and not by surface modification. Implications of our results for whisker mitigation strategies are discussed.

  6. 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/μm to 250 V/μm for film thicknesses of 1.3 to 3.5 μm. Capacitors based on CNETMS films exhibit extractable energy densities of 7 J/cm(3) at 300 V/μm, 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

  7. A silane-based electroactive film prepared in an imidazolium chloroaluminate molten salt

    SciTech Connect

    Carlin, R.T. . Frank J. Seiler Research Lab.); Osteryoung, R.A. . 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.

  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

    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. POLYMERIC ACRYLATE-BASED HYBRID FILMS CONTAINING LEAD AND IRON PATTERNED BY UV PHOTO-POLYMERIZATION

    PubMed Central

    Han, Huilan; Bissell, John; Yaghmaie, Frank; Davis, Cristina E.

    2009-01-01

    The development and processing of hybrid inorganic-organic thin film materials plays a critical role in advancing interdisciplinary sciences and device manufacturing. Here we present a novel approach to synthesize and deposit acrylate-containing organic/inorganic hybrid films. The material is based on a chemical solution and includes specifically desired metal dopants that are fully-integrated into the backbone of the polymer structure. The film can be deposited by simple spin coating, and we confer photosensitive properties to the material making it directly patterned by traditional UV photolithography techniques. Film thickness, chemical characterization and wet/dry etching capability of the film are also investigated. We believe this innovative material has the potential to be used in a broad range of applications for electronic, photonic, biology and other interdisciplinary fields. PMID:19795818

  10. 3D stress simulation and parameter design during twin-roll casting of 304 stainless steel based on the Anand model

    NASA Astrophysics Data System (ADS)

    Guo, Jing; Liu, Yuan-yuan; Liu, Li-gang; Zhang, Yue; Yang, Qing-xiang

    2014-07-01

    This study first investigated cracks on the surface of an actual steel strip. Formulating the Anand model in ANSYS software, we then simulated the stress field in the molten pool of type 304 stainless steel during the twin-roll casting process. Parameters affecting the stress distribution in the molten pool were analyzed in detail and optimized. After twin-roll casting, a large number of transgranular and intergranular cracks resided on the surface of the thin steel strip, and followed a tortuous path. In the molten pool, stress was enhanced at the exit and at the roller contact positions. The stress at the exit decreased with increasing casting speed and pouring temperature. To ensure high quality of the fabricated strips, the casting speed and pouring temperature should be controlled above 0.7 m/s and 1520°C, respectively.

  11. Theoretical investigation of acoustic wave devices based on different piezoelectric films deposited on silicon carbide

    NASA Astrophysics Data System (ADS)

    Fan, Li; Zhang, Shu-yi; Ge, Huan; Zhang, Hui

    2013-07-01

    Performances of acoustic wave (AW) devices based on silicon carbide (SiC) substrates are theoretically studied, in which two types of piezoelectric films of ZnO and AlN deposited on 4H-SiC and 3C-SiC substrates are adopted. The phase velocities (PV), electromechanical coupling coefficients (ECC), and temperature coefficients of frequency (TCF) for three AW modes (Rayleigh wave, A0 and S0 modes of Lamb wave) often used in AW devices are calculated based on four types of configurations of interdigital transducers (IDTs). It is found that that the ZnO piezoelectric film is proper for the AW device operating in the low-frequency range because a high ECC can be realized using a thin ZnO film. The AlN piezoelectric film is proper for the device operating in the high-frequency range in virtue of the high PV of AlN, which can increase the finger width of the IDT. Generally, in the low-frequency Lamb wave devices using ZnO piezoelectric films with small normalized thicknesses of films to wavelengths hf/λ, thin SiC substrates can increase ECCs but induce high TCFs simultaneously. In the high-frequency device with a large hf/λ, the S0 mode of Lamb wave based on the AlN piezoelectric film deposited on a thick SiC substrate exhibits high performances by simultaneously considering the PV, ECC, and TCF.

  12. Evaluation and improvement in the accuracy of a charge-coupled-device-based pyrometer for temperature field measurements of continuous casting billets

    NASA Astrophysics Data System (ADS)

    Bai, Haicheng; Xie, Zhi; Zhang, Yuzhong; Hu, Zhenwei

    2013-06-01

    This paper presents a radiometric high-temperature field measurement model based on a charge-coupled-device (CCD). According to the model, an intelligent CCD pyrometer with a digital signal processor as the core is developed and its non-uniformity correction algorithm for reducing the differences in accuracy between individual pixel sensors is established. By means of self-adaptive adjustment for the light-integration time, the dynamic range of the CCD is extended and its accuracy in low-temperature range is improved. The non-uniformity correction algorithm effectively reduces the accuracy differences between different pixel sensors. The performance of the system is evaluated through a blackbody furnace and an integrating sphere, the results of which show that the dynamic range of 400 K is obtained and the accuracy in low temperature range is increased by 7 times compared with the traditional method based on the fixed light-integration time. In addition, the differences of accuracy between the on-axis pixel and the most peripheral pixels are decreased from 19.1 K to 2.8 K. Therefore, this CCD pyrometer ensures that the measuring results of all pixels tend to be equal-accuracy distribution across the entire measuring ranges. This pyrometric system has been successfully applied to the temperature field measurements in continuous casting billets.

  13. Gafchromic EBT2 film dosimetry in reflection mode with a novel plan-based calibration method

    SciTech Connect

    Mendez, I.; Hartman, V.; Hudej, R.; Strojnik, A.; Casar, B.

    2013-01-15

    Purpose:A dosimetric system formed by Gafchromic EBT2 radiochromic film and Epson Expression 10000XL flatbed scanner was commissioned for dosimetry. In this paper, several open questions concerning the commissioning of radiochromic films for dosimetry were addressed: (a) is it possible to employ this dosimetric system in reflection mode; (b) if so, can the methods used in transmission mode also be used in reflection mode; (c) is it possible to obtain accurate absolute dose measurements with Gafchromic EBT2 films; (d) which calibration method should be followed; (e) which calibration models should be used; and (f) does three-color channel dosimetry offer a significant improvement over single channel dosimetry. The purpose of this paper is to help clarify these questions. Methods: In this study, films were scanned in reflection mode, the effect of surrounding film was evaluated and the feasibility of EBT2 film dosimetry in reflection mode was studied. EBT2's response homogeneity has been reported to lead to excessive dose uncertainties. To overcome this problem, a new plan-based calibration method was implemented. Plan-based calibration can use every pixel and each of the three color channels of the scanned film to obtain the parameters of the calibration model. A model selection analysis was conducted to select lateral correction and sensitometric curve models. The commonly used calibration with fragments was compared with red-channel plan-based calibration and with three-channel plan-based calibration. Results: No effect of surrounding film was found in this study. The film response inhomogeneity in EBT2 films was found to be important not only due to differences in the fog but also due to differences in sensitivity. The best results for lateral corrections were obtained using absolute corrections independent of the dose. With respect to the sensitometric curves, an empirical polynomial fit of order 4 was found to obtain results equivalent to a gamma

  14. Verification of Gamma Knife extend system based fractionated treatment planning using EBT2 film

    SciTech Connect

    Natanasabapathi, Gopishankar; Bisht, Raj Kishor

    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.

  15. 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.

  16. 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…

  17. Tensile properties of as-cast iron-aluminide alloys

    SciTech Connect

    Viswanathan, S.; McKamey, C.G.; Maziasz, P.J.

    1995-01-01

    Room-temperature tensile properties of as-cast Fe{sub 3}Al-based FA-129 alloy were investigated. Tensile properties were obtained in the as-cast condition in air, oxygen, and water-vapor environments, and after homogenization at 700, 900, and 1200{degrees}C. Transmission electron microscopy (MM) was used to characterize ordered phases and dislocation structure, and optical metallography and scanning electron microscopy (SEM) were used to characterize the grain microstructure and fracture morphology. Tensile properties in the as-cast condition exhibited an environmental effect; tensile ductilities in oxygen atmosphere were greater than those obtained in laboratory air. Homogenized samples of FA-129 alloy exhibited almost twice the ductility found in the as-cast condition. Microstructural characterization of the homogenized samples and comparison of the as-cast and homogenized microstructures provided clues that helped to explain the poor ductility in the as-cast state.

  18. [Analysis of spectral characteristics of oil film on water based on wavelet transform].

    PubMed

    Li, Ying; Liu, Bing-Xin; Li, Bao-Yu; Chen, Duo

    2012-07-01

    The diagnostic features are the basis to detect and characterize the oil film on water through optical remote sensing. This work shows the results of lab spectral measurements of light diesel oil with thickness ranged 1.0 - 127 microm. A wavelet transform were performed to the reflectance, and the singularity (388-393 nm) was explored as the indicators of oil film thickness. The results indicate that the reflectance of light diesel oil film is higher than that of water in the range from 350-2 500 nm. There is a reflectance peak near 388 nm when the thickness of oil film is larger than 6 microm, however, no distinguished features could be recognized when oil films were thinner than 6 microm. The wavelet coefficients of the fifth decomposition level by applying Daubechies 4 (db4) mother wavelets proved successful for identifying the singularity of oil film's reflectance spectra and its accurate position. With the thickness lager than 6 microm, the detail coefficients performed an abrupt change within the range of 388-393 nm, and became more violent while oil films' thickness increased. This research demonstrated that oil films on water with different thickness could be distinguished based on wavelet detail coefficients, with important implications for detection of oils on water using UV and short wave optical remote sensing. PMID:23016354

  19. Efficient ray casting with LF-Minmax map in CUDA

    NASA Astrophysics Data System (ADS)

    Choi, Jae

    2011-03-01

    Ray casting is the most frequently used algorithm in direct volume rendering for displaying medical data, although it is computationally very expensive. Recent hardware improvements have allowed ray casting to be used in real-time, however, there is room for performance gains to take advantage of the recent development of general-purpose graphical processing units (GPU). The purpose of this paper is to implement the volume ray casting with the Compute Unified Device Architecture (CUDA) to obtain higher rendering performance. The experimental results show that the new algorithm is up to 15 times faster than the conventional CPU-based ray casting algorithm.

  20. A system for digital reconstruction of gypsum dental casts.

    PubMed

    Goshtasby, A A; Nambala, S; deRijk, W G; Campbell, S D

    1997-10-01

    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 multiview range images of the cast without image registration. A method for calibrating the scanner is described and experimental results showing the accuracy of the scanner are presented. PMID:9368122

  1. 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

  2. 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

  3. Electroplated Fe-Co-Ni films prepared from deep-eutectic-solvent-based plating baths

    NASA Astrophysics Data System (ADS)

    Yanai, Takeshi; Shiraishi, Kotaro; Akiyoshi, Toshiki; Azuma, Keita; Watanabe, Yoshimasa; Ohgai, Takeshi; Morimura, Takao; Nakano, Masaki; Fukunaga, Hirotoshi

    2016-05-01

    We fabricated soft magnetic films from DES-based plating baths, and investigated magnetic properties of the plated films. The plating baths were obtained by stirring the mixture of choline chloride, ethylene glycol, FeCl2 ṡ 4H2O, NiCl2 ṡ 6H2O and CoCl2 ṡ 6H2O. The composition of the electroplated film depended on the amount of the reagent in the plating bath, and we consequently obtained the films with various composition. The current efficiency of the plating process shows high values (> 88 %) in the wide composition range. The soft magnetic films with low coercivity were obtained at the Fe compositions of ≈ 30 at.% and > 80 at.%, and we found that low coercivity could be realized by the control of the film composition. We also found that the Fe-rich films prepared from DES-based plating bath have some advantages as a soft magnetic phase for a nanocomposite magnet due to their high saturation magnetization and very fine crystal structure.

  4. Single Nanoparticle-Based Heteronanojunction as a Plasmon Ruler for Measuring Dielectric Thin Films.

    PubMed

    Li, Li; Hutter, Tanya; Li, Wenwu; Mahajan, Sumeet

    2015-06-18

    Nondestructive, noninvasive and accurate measurement of thin film thicknesses on dielectric substrates is challenging. In this work a ruler for measuring thin film thicknesses utilizes the heteronanojunction construct formed between a plasmonic nanoparticle and a high refractive index nonplasmonic substrate. The high near-field sensitivity in the nanojunction renders it suitable for measuring the thickness of intervening dielectric thin films. We demonstrate this by controlling the thickness of dielectric spacer layers created by overgrowing SiO2 thin films on commercially available silicon substrates. While Rayleigh (using dark-field) scattering measurements show that the spectral response is well correlated to the thickness of SiO2 spacer layers the distance-dependence is much steeper with surface-enhanced Raman scattering (SERS). Good agreement between 3D simulations and experimental results confirm the plasmon ruler construct's sensitivity to the dielectric thin film spacing. Thus, we postulate that this single nanoparticle based heteronanojunction configuration can serve as a convenient and simple ruler in metrology of thin films as well as a platform for SERS-based detection even in cases where plasmonically active films are not a suitable substrate. PMID:26266605

  5. Investigating the nature of graphene-based films prepared by vacuum filtration of graphene dispersions.

    PubMed

    Yi, Min; Liang, Shuaishuai; Liu, Lei; Shen, Zhigang; Zheng, Yiting; Zhang, Xiaojing; Ma, Shulin

    2014-07-01

    Though the graphene-based films prepared by vacuum filtration of graphene dispersions can be well and easily prepared so far and show great prospects in conductive, transparent, and flexible devices and coatings, the nature of these films has been rarely investigated. In order to reveal how graphene flakes constitute these films, herein we prepared a thin graphene-based film by vacuum filtering graphene dispersions and characterized the film by diverse techniques. Microscopic analyses evidenced the layer structure nature of the film. Raman spectra, transmission electron microscopy, and X-ray diffraction results indicate that the film is neither graphene nor graphite, but intrinsically a graphene block constituted by numerous graphene flakes which are randomly stacked. Though aggregation of graphene flakes happens in the filtration process, the aggregation is not a process to drive graphene flakes stacked in Bernal AB style to form bulk graphite. The adjoining graphene flakes are poorly coupled, likely due to the interlayer adventitious impurities introduced from liquid-phase processing. PMID:24757968

  6. 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.

  7. 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

  8. Ammonia gas sensors based on poly (3-hexylthiophene)-molybdenum disulfide film transistors

    NASA Astrophysics Data System (ADS)

    Xie, Tao; Xie, Guangzhong; Su, Yuanjie; Hongfei, Du; Ye, Zongbiao; Jiang, Yadong

    2016-02-01

    In this work, in order to enhance the recovery performance of organic thin film transistors (OTFTs) ammonia (NH3) sensors, poly (3-hexylthiophene) (P3HT) and molybdenum disulfide (MoS2) were combined as sensitive materials. Different sensitive film structures as active layers of OTFTs, i.e., P3HT-MoS2 composite film, P3HT/MoS2 bilayer film and MoS2/P3HT bilayer film were fabricated by spray technology. OTFT gas sensors based on P3HT-MoS2 composite film showed a shorter recovery time than others when the ammonia concentration changed from 4 to 20 ppm. Specifically, x-ray diffraction (XRD), Raman and UV-visible absorption were employed to explore the interface properties between P3HT and single-layer MoS2. Through the complementary characterization, a mechanism based on charge transfer is proposed to explain the physical originality of these OTFT gas sensors: closer interlayer d-spacing and better π-π stacking of the P3HT chains in composite film have ensured a short recovery time of OTFT gas sensors. Moreover, sensing mechanisms of OTFTs were further studied by comparing the device performance in the presence of nitrogen or dry air as a carrier gas. This work not only strengthens the fundamental understanding of the sensing mechanism, but provides a promising approach to optimizing the OTFT gas sensors.

  9. The potential of centrifugal casting for the production of near net shape uranium parts

    SciTech Connect

    Robertson, E.

    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.

  10. 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

  11. Transparent bionanocomposite films based on chitosan and TEMPO-oxidized cellulose nanofibers with enhanced mechanical and barrier properties.

    PubMed

    Soni, Bhawna; Hassan, El Barbary; Schilling, M Wes; Mahmoud, Barakat

    2016-10-20

    The development of biobased active films for use in food packaging is increasing due to low cost, environmental appeal, renewability and availability. The objective of this research was to develop an effective and complete green approach for the production of bionanocomposite films with enhanced mechanical and barrier properties. This was accomplished by incorporating TEMPO-oxidized cellulose nanofibers (2,2,6,6-tetramethylpiperidine-1-oxyl radical) into a chitosan matrix. An aqueous suspension of chitosan (100-75wt%), sorbitol (25wt%) and TEMPO-oxidized cellulose nanofibers (TEMPO-CNFs, 0-25wt%) were cast in an oven at 40°C for 2-4days. Films were preconditioned at 25°C and 50% RH for characterization. The surface morphology of the films was revealed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The thermal properties and crystal structure of the films were evaluated by thermogravimetric analysis (TGA-DTG) and X-ray diffraction (XRD). Incorporation of TEMPO-CNFs enhanced the mechanical strength of the films due to the high aspect ratio (3-20nm width, and 10-100nm length) of TEMPO-CNFs and strong interactions with the chitosan matrix. Oxygen and water vapor transmission rates for films that are prepared with chitosan and TEMPO-CNFs (15-25wt%) were significantly reduced. Furthermore, these bionanocomposite films had good thermal stability. Use of TEMPO-CNFs in this method makes it possible to produce bionanocomposite films that are flexible, transparent, and thus have potential in food packaging applications. PMID:27474625

  12. Method for casting polyethylene pipe

    NASA Technical Reports Server (NTRS)

    Elam, R. M., Jr.

    1973-01-01

    Short lengths of 7-cm ID polyethylene pipe are cast in a mold which has a core made of room-temperature-vulcanizable (RTV) silicone. Core expands during casting and shrinks on cooling to allow for contraction of the polyethylene.

  13. Three-dimensional registration of synchrotron radiation-based micro-computed tomography images with advanced laboratory micro-computed tomography data from murine kidney casts

    NASA Astrophysics Data System (ADS)

    Thalmann, Peter; Hieber, Simone E.; Schulz, Georg; Deyhle, Hans; Khimchenko, Anna; Kurtcuoglu, Vartan; Olgac, Ufuk; Marmaras, Anastasios; Kuo, Willy; Meyer, Eric P.; Beckmann, Felix; Herzen, Julia; Ehrbar, Stefanie; Müller, Bert

    2014-09-01

    Malfunction of oxygen regulation in kidney and liver may lead to the pathogenesis of chronic diseases. The underlying mechanisms are poorly understood. In kidney, it is hypothesized that renal gas shunting from arteries to veins eliminates excess oxygen. Such shunting is highly dependent on the structure of the renal vascular network. The vascular tree has so far not been quantified under maintenance of its connectivity as three-dimensional imaging of the vessel tree down to the smallest capillaries, which in mouse model are smaller than 5 μm in diameter, is a challenging task. An established protocol uses corrosion casts and applies synchrotron radiation-based micro-computed tomography (SRμCT), which provides the desired spatial resolution with the necessary contrast. However, SRμCT is expensive and beamtime access is limited. We show here that measurements with a phoenix nanotomrm (General Electric, Wunstorf, Germany) can provide comparable results to those obtained with SRμCT, except for regions with small vessel structures, where the signal-to-noise level was significantly reduced. For this purpose the nanotom®m measurement was compared with its corresponding measurement acquired at the beamline P05 at PETRA III at DESY, Hamburg, Germany.

  14. Chemical sensing employingpH sensitive emeraldine base thin film for carbon dioxide detection

    NASA Astrophysics Data System (ADS)

    Irimia-Vladu, Mihai

    Respiration, or CO2 evolution, is a universal indicator for all the biological activities. Among many potential applications, the measurement of CO2 evolution has been found to be a rapid and nondestructive means for examining microbial contamination of food. The sensor developed in this work consists of a thin emeraldine base-polyaniline (EB-PAni) film. In the first half of the project the effect of carbon dioxide over the conductivity of a composite film of emeraldine base polyaniline and poly(vinyl alcohol) in N-methyl pyrrolidone (NMP) respectively was tested. Argon gas or mixture of argon and 5% CO2 were circulated through the glass cell containing the polymer film deposited on interdigitated electrode and exposed to specific humidity levels fixed by aqueous supersaturated salt solutions. In the second half of the project, a thin emeraldine base film in NMP was directly deposited on interdigitated electrode and the respective sensor inserted in water. Carbonic acid solutions of various pHs were generated by bubbling specific mixtures of carbon dioxide and argon. Conductivity measurements were performed by impedance spectroscopy throughout the project. The sensing mechanism is based on intermediate stages of the transformation of the emeraldine base polyaniline to a conductive salt type (ES-PAni). This EB-ES transformation is the consequence of the exposure of EB-PAni to a protonic acid and is accompanied by a change in the conductivity of the polymer film. Carbonic acid, unfortunately, is a very weak acid and is unable to induce a conductivity change, but the intermediate steps that predetermine this transformation are detected by impedance spectroscopy even when the overall conductivity of the film is unchanged. The composite thin film developed in the first part of the project showed poor sensing characteristics: limited dynamic range, drift, instability and slow time response. However, the sensor design employed in the second half of this work, coupled with

  15. Correcting scan-to-scan response variability for a radiochromic film-based reference dosimetry system

    SciTech Connect

    Lewis, David; Devic, Slobodan

    2015-10-15

    Purpose: In radiochromic film dosimetry systems, measurements are usually obtained from film images acquired on a CCD-based flatbed scanner. The authors investigated factors affecting scan-to-scan response variability leading to increased dose measurement uncertainty. Methods: The authors used flatbed document scanners to repetitively scan EBT3 radiochromic films exposed to doses 0–1000 cGy, together with three neutral density filters and three blue optical filters. Scanning was performed under two conditions: scanner lid closed and scanner lid opened/closed between scans. The authors also placed a scanner in a cold room at 9 °C and later in a room at 22 °C and scanned EBT3 films to explore temperature effects. Finally, the authors investigated the effect of altering the distance between the film and the scanner’s light source. Results: Using a measurement protocol to isolate the contribution of the CCD and electronic circuitry of the scanners, the authors found that the standard deviation of response measurements for the EBT3 film model was about 0.17% for one scanner and 0.09% for the second. When the lid of the first scanner was opened and closed between scans, the average scan-to-scan difference of responses increased from 0.12% to 0.27%. Increasing the sample temperature during scanning changed the RGB response values by about −0.17, −0.14, and −0.05%/°C, respectively. Reducing the film-to-light source distance increased the RBG response values about 1.1, 1.3, and 1.4%/mm, respectively. The authors observed that films and film samples were often not flat with some areas up to 8 mm away from the scanner’s glass window. Conclusions: In the absence of measures to deal with the response irregularities, each factor the authors investigated could lead to dose uncertainty >2%. Those factors related to the film-to-light source distance could be particularly impactful since the authors observed many instances where the curl of film samples had the

  16. Brain-based decoding of mentally imagined film clips and sounds reveals experience-based information patterns in film professionals.

    PubMed

    de Borst, Aline W; Valente, Giancarlo; Jääskeläinen, Iiro P; Tikka, Pia

    2016-04-01

    In the perceptual domain, it has been shown that the human brain is strongly shaped through experience, leading to expertise in highly-skilled professionals. What has remained unclear is whether specialization also shapes brain networks underlying mental imagery. In our fMRI study, we aimed to uncover modality-specific mental imagery specialization of film experts. Using multi-voxel pattern analysis we decoded from brain activity of professional cinematographers and sound designers whether they were imagining sounds or images of particular film clips. In each expert group distinct multi-voxel patterns, specific for the modality of their expertise, were found during classification of imagery modality. These patterns were mainly localized in the occipito-temporal and parietal cortex for cinematographers and in the auditory cortex for sound designers. We also found generalized patterns across perception and imagery that were distinct for the two expert groups: they involved frontal cortex for the cinematographers and temporal cortex for the sound designers. Notably, the mental representations of film clips and sounds of cinematographers contained information that went beyond modality-specificity. We were able to successfully decode the implicit presence of film genre from brain activity during mental imagery in cinematographers. The results extend existing neuroimaging literature on expertise into the domain of mental imagery and show that experience in visual versus auditory imagery can alter the representation of information in modality-specific association cortices. PMID:26826515

  17. Synthesis of Meltspun Multiwall Carbon Nanotube/Polycarbonate Fibers Through Solvent Casting and Melt Extrusion.

    PubMed

    Yadav, Poonam; Park, Sang Whan; Lee, Dong Bok

    2015-11-01

    Films and strands consisting of polycarbonate (PC) containing 0.55 or 0.75 wt% multiwall carbon nanotubes (MWNTs) were synthesized through solvent casting and melt extrusion methods, respectively. They were further processed into fibers through melt spinning. Fibers made from melt-extruded strands exhibited a smoother surface, more uniform morphology, and better dispersion of MWNTs in PC than those made from solvent-cast films. PMID:26726657

  18. Predicting the optoelectronic properties of nanowire films based on control of length polydispersity.

    PubMed

    Large, Matthew J; Burn, Jake; King, Alice A; Ogilvie, Sean P; Jurewicz, Izabela; Dalton, Alan B

    2016-01-01

    We demonstrate that the optoelectronic properties of percolating thin films of silver nanowires (AgNWs) are predominantly dependent upon the length distribution of the constituent AgNWs. A generalized expression is derived to describe the dependence of both sheet resistance and optical transmission on this distribution. We experimentally validate the relationship using ultrasonication to controllably vary the length distribution. These results have major implications where nanowire-based films are a desirable material for transparent conductor applications; in particular when application-specific performance criteria must be met. It is of particular interest to have a simple method to generalize the properties of bulk films from an understanding of the base material, as this will speed up the optimisation process. It is anticipated that these results may aid in the adoption of nanowire films in industry, for applications such as touch sensors or photovoltaic electrode structures. PMID:27158132

  19. Predicting the optoelectronic properties of nanowire films based on control of length polydispersity

    NASA Astrophysics Data System (ADS)

    Large, Matthew J.; Burn, Jake; King, Alice A.; Ogilvie, Sean P.; Jurewicz, Izabela; Dalton, Alan B.

    2016-05-01

    We demonstrate that the optoelectronic properties of percolating thin films of silver nanowires (AgNWs) are predominantly dependent upon the length distribution of the constituent AgNWs. A generalized expression is derived to describe the dependence of both sheet resistance and optical transmission on this distribution. We experimentally validate the relationship using ultrasonication to controllably vary the length distribution. These results have major implications where nanowire-based films are a desirable material for transparent conductor applications; in particular when application-specific performance criteria must be met. It is of particular interest to have a simple method to generalize the properties of bulk films from an understanding of the base material, as this will speed up the optimisation process. It is anticipated that these results may aid in the adoption of nanowire films in industry, for applications such as touch sensors or photovoltaic electrode structures.

  20. Heterojunction thin films based on multifunctional metal oxides for photovoltaic application

    SciTech Connect

    Prabhu, M.; Soundararajan, N.; Ramachandran, K.; Marikkannan, M.; Mayandi, J.

    2014-04-24

    Metal oxides based multifunctional heterojunction thin films of ZnO/SnO{sub 2} and ZnO/SnO{sub 2}/CuO QDs were prepared by spin-coating technique. The crystallographic properties and the surface morphologies of the films were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM), respectively. The optical absorption studies revealed that the film thickness has considerable effect on the band gap values and is found to be in the range of 3.73–3.48 eV. The photoluminescence spectra showed several weak visible emission peaks related to the deep level defects (450-575 nm). Finally, the current density-voltage (J-V) characteristic of ZnO/SnO{sub 2}/CuO QDs (ZSCI) based heterojunction thin film coated on ITO is also reported.