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Sample records for based cast films

  1. 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.

  2. 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

  3. Influence of casting solvent on phenyl ordering at the surface of spin cast polymer thin films.

    PubMed

    Myers, John N; Zhang, Chi; Chen, Chunyan; Chen, Zhan

    2014-06-01

    Controlling the surface molecular structure of spin cast polymer films is important for the rational design of surface properties. However, the relationship between spin casting parameters and film surface molecular structure is poorly understood. We report that the surface molecular structure of spin cast homopolymers which contain phenyl groups is influenced by the solvent aromaticity, investigated by a nonlinear optical spectroscopy, sum frequency generation (SFG) vibrational spectroscopy. When phenyl groups were located in a linear polymer backbone, spin casting with aromatic solvents enhanced the phenyl SFG signal relative to when a non-aromatic solvent was used which suggests that the aromatic solvent induced the surface phenyl groups to be more ordered and/or to lie more perpendicular to the film surface. In addition, when alkyl structures were believed to be present at the solvent/air interface, alkyl structures were observed at the film/air interface which suggests that molecular structure at the solvent/air interface was carried to the film surface. The effects of solvent aromaticity on phenyl ordering at spin cast film surfaces can be explained by different molecular structures of polymer chains at solvent/air interfaces, preferential solvation of functional groups during evaporation, and re-orientation of bulky side groups at the polymer film/air interface. PMID:24703669

  4. Land-based turbine casting initiative

    SciTech Connect

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

    1995-12-31

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

  5. 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.

  6. Bifilm Defects in Ni-Based Alloy Castings

    NASA Astrophysics Data System (ADS)

    Campbell, John; Tiryakio?lu, 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.

  7. Interfacial glass transition profiles in ultrathin, spin cast polymer films.

    PubMed

    Sills, Scott; Overney, René M; Chau, Wilson; Lee, Victor Y; Miller, Robert D; Frommer, Jane

    2004-03-15

    Interfacial glass transition temperature (T(g)) profiles in spin cast, ultrathin films of polystyrene and derivatives were investigated using shear-modulated scanning force microscopy. The transitions were measured as a function of film thickness (delta), molecular weight, and crosslinking density. The T(g)(delta) profiles were nonmonotonic and exhibited two regimes: (a) a sublayer extending about 10 nm from the substrate, with T(g) values lowered up to approximately 10 degrees C below the bulk value, and (b) an intermediate regime extending over 200 nm beyond the sublayer, with T(g) values exceeding the bulk value by up to 10 degrees C. Increasing the molecular weight was found to shift the T(g)(delta) profiles further from the substrate interface, on the order of 10 nm/kDa. Crosslinking the precast films elevated the absolute T(g) values, but had no effect on the spatial length scale of the T(g)(delta) profiles. These results are explained in the context of film preparation history and its influence on molecular mobility. Specifically, the observed rheological anisotropy is interpreted based on the combined effects of shear-induced structuring and thermally activated interdiffusion. PMID:15267406

  8. 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...

  9. 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 ...

  10. 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).

  11. Effect of clay platelet orientation on spin cast nanocomposite films

    NASA Astrophysics Data System (ADS)

    Li, J.; Schwarz, S. A.; Ji, Y.; Rafailovich, M. H.; Sokolov, J.; Rudomen, G.; Feng, W. H.

    2006-09-01

    The authors show that the thickness of spin cast nanocomposite polystyrene/clay films displays a large radial dependence that is not explained by current models. Transmission electron microscopy and atomic force microscopy reveal a tendency for the high aspect ratio clay particles to align in the direction of shear. Near the center of rotation, particles remain randomly oriented leading to the formation of voids as the film dries. They present a two dimensional numerical model that incorporates both hydrodynamic and orientation effects and accurately fits the thickness data over a wide range of filler concentrations and spin rates.

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

    SciTech Connect

    Shao, Ming; Keum, Jong Kahk; Kumar, Rajeev; Chen, Jihua; Browning, Jim; Chen, Wei; Jianhui, Hou; Do, Changwoo; Littrell, Ken; Sanjib, Das; Rondinone, Adam Justin; Geohegan, David B; Sumpter, Bobby G; Xiao, Kai

    2014-01-01

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

  13. Interfacial thermal conductance in spun-cast polymer films and polymer brushes

    E-print Network

    Braun, Paul

    Interfacial thermal conductance in spun-cast polymer films and polymer brushes Mark D. Losego thermal conductivity of amorphous polymers limits significant interfacial effects to polymer film effects in the thermal conductance of spun-cast poly methyl methacrylate PMMA thin films and PMMA brushes

  14. 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.

  15. 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

  16. 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.

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

  18. Oxide films, pores and the fatigue lives of cast aluminum alloys

    NASA Astrophysics Data System (ADS)

    Wang, Q. G.; Crepeau, P. N.; Davidson, C. J.; Griffiths, J. R.

    2006-12-01

    In the absence of gross defects such as cold shuts, the fatigue properties of castings are largely determined by the sizes of microstructural defects, particularly pores and oxide films. In contrast, the effects of grain size, second-phase particles, and nonmetallic inclusions are insignificant. The authors review the fatigue properties of castings made by gravity die casting, sand casting, lost-foam casting, squeeze casting, and semisolid casting, and compare A356/357 alloys with 319-type alloys. The application of fracture mechanics enables the properties to be rationalized in terms of the defects that are characteristic of each casting process, noting both the sizes and types of defect. The differences in the properties of castings are entirely attributed to their different defect populations. No single process is inherently superior. For defects of the same size (in terms of projected area normal to the loading direction), oxide films are less detrimental to fatigue life than pores. Areas of current controversy are highlighted and suggestions for further work are made.

  19. Characterization of Bimetallic Castings with an Austenitic Working Surface Layer and an Unalloyed Cast Steel Base

    NASA Astrophysics Data System (ADS)

    Wróbel, Tomasz

    2014-05-01

    The paper presents the technology of bimetallic castings based on the founding method of layer coating directly in the cast process of the so-called method of mold cavity preparation. The prepared castings consist of two fundamental parts, i.e., the base and the working surface layer. The base part of the bimetallic casting is typical foundry material, i.e., unalloyed cast steel, whereas the working layer is a plate of austenitic alloy steel sort X2CrNi 18-9. The quality of the joint between the base part and the working layer was evaluated on the basis of ultrasonic non-destructive testing and structure examinations containing metallographic macro- and microscopic studies with the use of a light microscope (LOM) with microhardness measurements and a scanning electron microscope (SEM) with microanalysis of the chemical composition (energy dispersive spectroscopy—EDS). On the basis of the obtained results it was confirmed that the decisive phenomena needed to create a permanent joint between the two components of the bimetallic casting are carbon and heat transport in the direction from the high-carbon and hot base material which was poured into the mold in the form of liquid metal to the low-carbon and cold material of the working layer which was placed in the mold cavity in the form of a monolithic insert.

  20. 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, ...

  1. 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.

  2. An adjustable, cast based, fully restrictive surgical guide.

    PubMed

    Stumpel, Lambert J

    2015-05-01

    The 3D Click Guide is a fully restrictive cast-based surgical guide for the placement of dental implants. This in-office system consists of prefabricated parts that are assembled onto a carrier. The 3-dimensional data are derived from a dental cast in combination with a periapical radiograph or cone-beam computed tomography data. PMID:25858213

  3. 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.

  4. 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

  5. 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

  6. 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

  7. 56. DETAIL OF BASE OF STEEL WINDMILL TOWER WITH CAST ...

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

    56. DETAIL OF BASE OF STEEL WINDMILL TOWER WITH CAST IRON HAND PUMP OVER WELL HEAD ON HIGHWAY L44 IN IOWA JUST EAST OF NEBRASKA CITY, NEBRASKA. - Kregel Windmill Company Factory, 1416 Central Avenue, Nebraska City, Otoe County, NE

  8. 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

  9. 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 maleic anhydride (MA) affected mechanical properties and oxygen permeability with ultrasonic treatment to higher extent. However, use of compatibilizers led to a higher die pressure and resulted in opaque cast films. The mechanical properties were in agreement with crystallinity of samples. The exfoliated structure was achieved for PA6/clay 30B nanocomposites prepared using ultrasonically assisted single screw extrusion except for untreated nanocomposites containing 10 wt% of clay 30B. Untreated 92.5/7.5 and 90/10 PA6/clay 30B blown films showed the intercalated structure, but the exfoliated structure was achieved with ultrasonic treatment. All cast films of PA6/clay 30B showed the exfoliated structure. FTIR spectroscopy along with XRD results confirmed the existence of alpha and gamma-type crystals in the cast films, with clay particles favoring the formation of gamma-type crystals, and ultrasonic treatment favoring the formation of alpha-type crystals. Both parameters increased crystallinity of cast films improving their mechanical properties and oxygen permeability.

  10. 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.

  11. Radial Dependence of Spin-Cast Polymer/Clay Nanocomposite Film Thickness

    NASA Astrophysics Data System (ADS)

    Li, Jun; Singh, Avtar; Schiffman, Scott; Kapoor, Deepak; Schwarz, Steven; Sokolov, Jonathan; Rafailovich, Miriam

    2004-03-01

    The thickness of spin-cast PS (polystyrene), PMMA (polymethylmethacrylate), and PB (polybutadiene) films on silicon wafers are examined as a function of solvent concentration, concentration of clay (Cloisite 6A) filler, and spin rate. A strong radial dependence of film thickness is observed in the clay composite films. As film thickness is a competition between evaporation rate and viscous flow, these properties are independently measured. Evaporation is determined by weight loss measurements, while viscosity vs. shear rate is measured in an ARES rheometer. Film thickness for composite films is determined by measuring scratch depths with a Dektak surface profilometer. Clay orientation within the film is examined by transmission electron microscopy. The viscosity and evaporation rate data are fed into a simple computer algorithm, which provides a semi-quantitative description of the data obtained. The radial dependence predicted by this simple physical model is too weak, however, most probably owing to the effects of clay platelet alignment during the spinning process.

  12. 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

  13. Awareness programs and change in taste-based caste prejudice.

    PubMed

    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

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

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

    PubMed

    Singhal, Nancy; Datta, Anindya

    2015-02-12

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

  16. 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

  17. 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.

  18. Rheological and Film-Casting Properties of Well-Characterised Polyethylenes with Different Branching Structure

    NASA Astrophysics Data System (ADS)

    Auhl, Dietmar; Kunamaneni, Suneel; Seay, Christopher W.; McGrady, Christopher D.; Baird, Donald G.; McLeish, Tom C. B.

    2008-07-01

    We investigated the influence of branching structure on cast-film properties, i.e. the neck-in profile and final cast-film dimensions, for a series of metallocene catalysed PE as well as tubular reactor PE with various branching levels. For this study a lab extruder has been employed due to the small sample quantities available. The materials and flow conditions have been chosen specifically in order to match for various polyethylenes with different molecular structures at the die exit. Non-linear visco-elastic properties in shear and uniaxial elongation have been determined from constant strain-rate tests and fitted with a multi-mode Pom-Pom model, the parameters of which are discussed with respect to the molecular analysis of the branching structure. The experimental results for the film-casting behaviour as a function of long-chain branching content and draw ratio will be further compared to model predictions using recent theoretical approaches together with the Pom-Pom constitutive equation.

  19. 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

  20. 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.

  1. Method of casting pitch based foam

    DOEpatents

    Klett, James W. (Knoxville, TN)

    2002-01-01

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

  2. Flexible, transparent nanocomposite film with a large clay component and ordered structure obtained by a simple solution-casting method.

    PubMed

    Shikinaka, Kazuhiro; Aizawa, Kazuto; Fujii, Nozomu; Osada, Yoshihito; Tokita, Masatoshi; Watanabe, Junji; Shigehara, Kiyotaka

    2010-08-01

    A flexible, transparent nanocomposite (NC) film with 57 wt % inorganic components was obtained by the simple casting of a solution of Laponite and modified organic molecules through a sol-gel reaction. The NC film has solvent resistance and a disco-nematic liquid-crystalline-like structure of Laponite that originates from the cross linking of Laponite by silanol agents and the large amount of Laponite in the film. PMID:20586428

  3. Fluid casting of particle-based articles

    DOEpatents

    Menchhofer, Paul (Oak Ridge, TN)

    1995-01-01

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

  4. 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.

  5. FLATNESS BASED OPEN LOOP CONTROL FOR THE TWIN ROLL STRIP CASTING

    E-print Network

    Ollivier, François

    casting to produce thin strips (1-60 mm thickness). Among lower investment and pro- duction costs, thinFLATNESS BASED OPEN LOOP CONTROL FOR THE TWIN ROLL STRIP CASTING PROCESS Ch. Fleck ,1 Th. Paulus ,2, D-52074 Aachen, Germany Abstract: Strip casting technology is the most recent innovative steel

  6. FLATNESS BASED OPEN LOOP CONTROL FOR THE TWIN ROLL STRIP CASTING

    E-print Network

    Ollivier, François

    casting to produce thin strips (1­60 mm thickness). Among lower investment and pro­ duction costs, thinFLATNESS BASED OPEN LOOP CONTROL FOR THE TWIN ROLL STRIP CASTING PROCESS Ch. Fleck #,1 Th. Paulus, Steinbachstr. 54, D­52074 Aachen, Germany Abstract: Strip casting technology is the most recent innovative

  7. Precursor-route ZnO films from a mixed casting solvent for high performance aqueous electrolyte-gated transistors.

    PubMed

    Althagafi, Talal M; Algarni, Saud A; Al Naim, Abdullah; Mazher, Javed; Grell, Martin

    2015-11-18

    We significantly improved the performance of precursor-route semiconducting zinc oxide (ZnO) films in electrolyte-gated thin film transistors (TFTs). We find that the organic precursor to ZnO, zinc acetate (ZnAc), dissolves more readily in a 1?:?1 mixture of ethanol (EtOH) and acetone than in pure EtOH, pure acetone, or pure isopropanol. XPS and SEM characterisation show improved morphology of ZnO films converted from a mixed solvent cast ZnAc precursor compared to the EtOH cast precursor. When gated with a biocompatible electrolyte, phosphate buffered saline (PBS), ZnO thin film transistors (TFTs) derived from mixed solvent cast ZnAc give 4 times larger field effect current than similar films derived from ZnAc cast from pure EtOH. The sheet resistance at VG = VD = 1 V is 30 k? ?(-1), lower than for any organic TFT, and lower than for any electrolyte-gated ZnO TFT reported to date. PMID:26549322

  8. 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.

  9. Sensor-Based Assessment of Cast Placement and Removal

    PubMed Central

    MAAG, Anne-Lise D.; LAUFER, Shlomi; KWAN, Calvin; COHEN, Elaine R.; LENHART, Rachel L.; STORK, Natalie C.; HALANSKI, Matthew A.; PUGH, Carla M.

    2014-01-01

    Appropriate pressure during the application of a cast is critical to provide adequate stabilization of fractures. Force-sensing resistors (FSR) were used to measure pressure during cast placement and removal. The data demonstrated a signature pattern of skin pressure during the different steps of cast placement and removal. This reproducible signal provides validity evidence for our model. PMID:24732518

  10. Sensor-based assessment of cast placement and removal.

    PubMed

    Maag, Anne-Lise D; Laufer, Shlomi; Kwan, Calvin; Cohen, Elaine R; Lenhart, Rachel L; Stork, Natalie C; Halanski, Matthew A; Pugh, Carla M

    2014-01-01

    Appropriate pressure during the application of a cast is critical to provide adequate stabilization of fractures. Force-sensing resistors (FSR) were used to measure pressure during cast placement and removal. The data demonstrated a signature pattern of skin pressure during the different steps of cast placement and removal. This reproducible signal provides validity evidence for our model. PMID:24732518

  11. 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

  12. The Simulation of Magnesium Wheel Low Pressure Die Casting Based on PAM-CAST

    NASA Astrophysics Data System (ADS)

    Peng, Yinghong; Wang, Yingchun; Li, Dayong; Zeng, Xiaoqin

    2004-06-01

    Magnesium is the lightest metal commonly used in engineering, with various excellent characteristics such as high strength and electromagnetic interference shielding capability. Particularly, the usage of magnesium in automotive industry can meet better the need to reduce fuel consumption and CO2 emissions. Nowadays, most current magnesium components in automobiles are made by die casting. In this paper, commercial software for die casting, PAM-CAST™, was utilized to simulate the low pressure die casting process of magnesium wheel. Through calculating temperature field and velocity field during filling and solidification stages, the evolution of temperature distribution and liquid fraction was analyzed. Then, the potential defects including the gas entrapments in the middle of the spokes, shrinkages between the rim and the spokes were forecasted. The analytical results revealed that the mold geometry and die casting parameters should be improved in order to get the sound magnesium wheel. The reasons leading to these defects were also analyzed and the solutions to eliminate them were put forward. Furthermore, through reducing the pouring velocity, the air gas entrapments and partial shrinkages were eliminated effectively.

  13. Pectin- and gelatin-based film: effect of gamma irradiation on the mechanical properties and biodegradation

    NASA Astrophysics Data System (ADS)

    Jo, Cheorun; Kang, Hojin; Lee, Na Young; Kwon, Joong Ho; Byun, Myung Woo

    2005-04-01

    Agricultural by-products, pectin and gelatin, were used to prepare a biodegradable film. The film casting solution including the pectin and gelatin was irradiated at 0, 10, 20, and 30 kGy to investigate the irradiation effect on the mechanical properties of the film. The tensile strength of the 10 kGy-irradiated film was the highest among the treatments but the elongation at break, water vapour permeability, and swelling ratio were the lowest. Hunter color L*- and a*-values decreased but the b*-value increased as the irradiation dose increased. The total organic carbon content produced from the Paenibacillus polymyxa and Pseudomonas aeruginosa also showed that the film of 10 kGy-irradiated was lower than those of 0, 20, and 30 kGy-irradiated films. In conclusion, irradiation of the film casting solution at 10 kGy increased the mechanical properties of the pectin and gelatin based film. To manufacture the film by agricultural by-products, however, the irradiation dose of the film casting solution should be determined to achieve better mechanical properties.

  14. Nanocrystalline cellulose (NCC) reinforced alginate based biodegradable nanocomposite film.

    PubMed

    Huq, Tanzina; Salmieri, Stephane; Khan, Avik; Khan, Ruhul A; Le Tien, Canh; Riedl, Bernard; Fraschini, Carole; Bouchard, Jean; Uribe-Calderon, Jorge; Kamal, Musa R; Lacroix, Monique

    2012-11-01

    Nanocrystalline cellulose (NCC) reinforced alginate-based nanocomposite film was prepared by solution casting. The NCC content in the matrix was varied from 1 to 8% ((w/w) % dry matrix). It was found that the nanocomposite reinforced with 5 wt% NCC content exhibits the highest tensile strength which was increased by 37% compared to the control. Incorporation of NCC also significantly improved water vapor permeability (WVP) of the nanocomposite showing a 31% decrease due to 5 wt% NCC loading. Molecular interactions between alginate and NCC were supported by Fourier Transform Infrared Spectroscopy. The X-ray diffraction studies also confirmed the appearance of crystalline peaks due to the presence of NCC inside the films. Thermal stability of alginate-based nanocomposite films was improved after incorporation of NCC. PMID:22944444

  15. 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

  16. Preparation and characterization of bio-based hybrid film containing chitosan and silver nanowires.

    PubMed

    Shahzadi, Kiran; Wu, Lin; Ge, Xuesong; Zhao, Fuhua; Li, Hui; Pang, Shuping; Jiang, Yijun; Guan, Jing; Mu, Xindong

    2016-02-10

    A bio-based hybrid film containing chitosan (CS) and silver nanowires (AgNWs) has been prepared by a simple casting technique. X-ray diffraction (XRD), Fourier infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and UV-visible spectroscopy were employed to characterize the structure of bio-based film. The bio-based hybrid film showed unique performance compared with bare chitosan film. The incorporated nano-silver could improve the strength properly. The results revealed that AgNWs in CS film, improved its tensile strength more than 62% and Young modulus 55% compared with pure chitosan film. On the other hand tensile strength was increased 36.7% with AgNPs. Importantly, the film also exhibited conductivity and antibacterial properties, which may expand its future application. PMID:26686186

  17. Conical surface structures on model thin-film electrodes and tape-cast electrode materials for lithium-ion batteries

    NASA Astrophysics Data System (ADS)

    Kohler, R.; Proell, J.; Bruns, M.; Ulrich, S.; Seifert, H. J.; Pfleging, W.

    2013-07-01

    Three-dimensional structures in cathode materials for lithium-ion batteries were investigated in this study. For this purpose, laser structuring of lithium cobalt oxide was investigated at first for a thin-film model system and in a second step for conventional tape-cast electrode materials. The model thin-film cathodes with a thickness of 3 ?m were deposited using RF magnetron sputtering on stainless steel substrates. The films were structured via excimer laser radiation with a wavelength of 248 nm. By adjusting the laser fluence, self-organized conical microstructures were formed. Using conventional electrodes, tape-cast cathodes made of LiCoO2 with a film thickness of about 80 ?m on aluminum substrates were studied. It was shown that self-organizing surface structures could be formed by adjustment of the laser parameters. To investigate the formation mechanisms of the conical topography, the element composition was studied by time-of-flight secondary ion mass spectrometry and X-ray photoelectron spectroscopy. Electrochemical cycling using a lithium anode and conventional electrolyte was applied to study the influence of the laser processing procedures on cell performance. For the model electrode system, a significantly higher discharge capacity of 80 mAh/g could be obtained after 110 cycles by laser structuring compared to 8 mAh/g of the unstructured thin film. On conventional tape-cast electrodes self-organized surface structures could also increase the cycling stability resulting in an 80 % increase in capacity after 110 cycles in comparison to the unstructured electrode.

  18. Influence of S. mutans on base-metal dental casting alloy toxicity.

    PubMed

    McGinley, E L; Dowling, A H; Moran, G P; Fleming, G J P

    2013-01-01

    We have highlighted that exposure of base-metal dental casting alloys to the acidogenic bacterium Streptococcus mutans significantly increases cellular toxicity following exposure to immortalized human TR146 oral keratinocytes. With Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), S. mutans-treated nickel-based (Ni-based) and cobalt-chromium-based (Co-Cr-based) dental casting alloys were shown to leach elevated levels of metal ions compared with untreated dental casting alloys. We targeted several biological parameters: cell morphology, viable cell counts, cell metabolic activity, cell toxicity, and inflammatory cytokine expression. S. mutans-treated dental casting alloys disrupted cell morphology, elicited significantly decreased viable cell counts (p < 0.0001) and cell metabolic activity (p < 0.0001), and significantly increased cell toxicity (p < 0.0001) and inflammatory cytokine expression (p < 0.0001). S. mutans-treated Ni-based dental casting alloys induced elevated levels of cellular toxicity compared with S. mutans-treated Co-Cr-based dental casting alloys. While our findings indicated that the exacerbated release of metal ions from S. mutans-treated base-metal dental casting alloys was the likely result of the pH reduction during S. mutans growth, the exact nature of mechanisms leading to accelerated dissolution of alloy-discs is not yet fully understood. Given the predominance of S. mutans oral carriage and the exacerbated cytotoxicity observed in TR146 cells following exposure to S. mutans-treated base-metal dental casting alloys, the implications for the long-term stability of base-metal dental restorations in the oral cavity are a cause for concern. PMID:23103633

  19. Three-dimensional microstructure simulation of Ni-based superalloy investment castings

    NASA Astrophysics Data System (ADS)

    Pan, Dong; Xu, Qingyan; Liu, Baicheng

    2011-05-01

    An integrated macro and micro multi-scale model for the three-dimensional microstructure simulation of Ni-based superalloy investment castings was developed, and applied to industrial castings to investigate grain evolution during solidification. A ray tracing method was used to deal with the complex heat radiation transfer. The microstructure evolution was simulated based on the Modified Cellular Automaton method, which was coupled with three-dimensional nested macro and micro grids. Experiments for Ni-based superalloy turbine wheel investment casting were carried out, which showed a good correspondence with the simulated results. It is indicated that the proposed model is able to predict the microstructure of the casting precisely, which provides a tool for the optimizing process.

  20. Fabrication and characterization of thick-film piezoelectric lead zirconate titanate ceramic resonators by tape-casting.

    PubMed

    Qin, Lifeng; Sun, Yingying; Wang, Qing-Ming; Zhong, Youliang; Ou, Ming; Jiang, Zhishui; Tian, Wei

    2012-12-01

    In this paper, thick-film piezoelectric lead zirconate titanate (PZT) ceramic resonators with thicknesses down to tens of micrometers have been fabricated by tape-casting processing. PZT ceramic resonators with composition near the morphotropic phase boundary and with different dopants added were prepared for piezoelectric transducer applications. Material property characterization for these thick-film PZT resonators is essential for device design and applications. For the property characterization, a recently developed normalized electrical impedance spectrum method was used to determine the electromechanical coefficient and the complex piezoelectric, elastic, and dielectric coefficients from the electrical measurement of resonators using thick films. In this work, nine PZT thick-film resonators have been fabricated and characterized, and two different types of resonators, namely thickness longitudinal and transverse modes, were used for material property characterization. The results were compared with those determined by the IEEE standard method, and they agreed well. It was found that depending on the PZT formulation and dopants, the relative permittivities ?(T)(33)/?(0) measured at 2 kHz for these thick-films are in the range of 1527 to 4829, piezoelectric stress constants (e(33) in the range of 15 to 26 C/m(2), piezoelectric strain constants (d(31)) in the range of -169 × 10(-12) C/N to -314 × 10(-12) C/N, electromechanical coupling coefficients (k(t)) in the range of 0.48 to 0.53, and k(31) in the range of 0.35 to 0.38. The characterization results shows tape-casting processing can be used to fabricate high-quality PZT thick-film resonators, and the extracted material constants can be used to for device design and application. PMID:23221230

  1. 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

  2. Facile preparation and thermoelectric properties of Bi?Te? 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 ?Wm(-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

  3. Morphological, Mechanical and Thermal Study of ZnO Nanoparticle Reinforced Chitosan Based Transparent Biocomposite Films

    NASA Astrophysics Data System (ADS)

    Das, Kunal; Maiti, Sonakshi; Liu, Dagang

    2014-04-01

    Chitosan based biocomposite transparent films reinforced with zinc oxide (ZnO) nanoparticles at different loading i.e. 2, 4 and 6 wt% were successfully prepared by solution casting method. Shape, size and geometry of the zinc oxide nanoparticles were characterized by scanning electron microscopy (SEM). The biocomposite films were subjected to mechanical characterization, thermal analysis, morphology study and moisture uptake behaviour. The characterization tools used here include wide angle X-ray diffraction study, scanning electron microscopic analysis, differential scanning calorimetric analysis and also UV-visible transmittance behavior. SEM micrographs revealed uniformly dispersed ZnO nanoparticles in biocomposite films. Improvement of the tensile strength about 133 % was observed significantly in case of 4 wt% loaded chitosan/ZnO films with respect to the neat chitosan film. 43 % higher transparency was observed in case of 2 wt% ZnO loaded biocomposites films, thus indicating the best combination of properties of 2 wt% ZnO loaded biocomposite films.

  4. GRAIN REFINEMENT OF PERMANENT MOLD CAST COPPER BASE ALLOYS

    SciTech Connect

    M. SADAYAPPAN, J.P. THOMSON, M.ELBOUJDAINI, G. PING GU, M. SAHOO

    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. Aluminum promoted b phase formation and modified the grain structure from dendritic to equiaxed. Lead or bismuth reduces the size of grains, but not change the morphology of the structure in Cu-Zn alloys. The grain size of the Cu-Zn-alloy can be reduced from 3000 mm to 300 mm after the addition of aluminum and lead. Similar effects were observed in EnviroBrass III after the addition of aluminum and bismuth. Boron refined the structure of yellow brasses in the presence of iron. At least 50 ppm of iron and 3 ppm of boron are necessary to cause grain refinement in these alloys. Precipitation of iron from the melt is identified as the cause of grain refinement. Boron initiates the precipitation of iron which could not be explained at this time. On the other hand zirconium causes some reduction in grain size in all four alloys investigated. The critical limit for the zirconium was found to be around 100 ppm below which not much refinement could be observed. The mechanism of grain refinement in the presence of zirconium could not be explained. Grain refinement by boron and iron can remain over a long period of time, at least for 72 hours of holding or after remelting few times. It is necessary to have the iron and boron contents above the critical limits mentioned earlier. On the other hand, refinement by zirconium is lost quite rapidly, some times within one hour of holding, mostly due to the loss of zirconium, most probably by oxidation, from the melt. In all the cases it is possible to revive the refinement by adding more of the appropriate refining element. Cooling curve analysis (thermal analysis) can be used successfully to predict the grain refinement in yellow brasses. The precipitation of iron in the liquid metal causes the metal to solidify without undercooling. Absence of this reaction, as indicated by the time-temperature (t-T) and its first derivative (dt/dT) curves, proved to be an indicator of refinement. The viability of the technique as an on-line quality control tool was proved in two foundries. The method can also correctly predict the onset of fading. Th

  5. Cellular activity of Wharton's Jelly-derived mesenchymal stem cells on electrospun fibrous and solvent-cast film scaffolds.

    PubMed

    Bagher, Zohreh; Ebrahimi-Barough, Somayeh; Azami, Mahmoud; Safa, Majid; Joghataei, Mohammad Taghi

    2016-01-01

    It was shown that topography and surface chemistry of materials influence cell behaviors. In this study, the effects of chemistry and topography of scaffold surface on adhesion, proliferation and differentiation of Wharton's Jelly mesenchymal (WJMSCs) stem cells into motor neurons were investigated. WJMSCs were cultivated in an neurogenic inductive medium on the surface of modified and unmodified polycaprolactone (PCL) electrospun fibrous and solvent-cast film scaffolds. All the scaffolds were characterized according to their ability to support cell attachment and viability by SEM and MTT assay. The expression of motor neuron-specific markers was assayed by real-time PCR after 15days post induction. Results showed that attachment, proliferation and differentiation of WJMSCs into motor neuron-like cells on the nanotopographic surface was higher than that of the cells on the solvent-cast scaffolds. In addition, regardless of their topography, WJMSCs cultured on collagen-coated PCL nanofibrous showed results similar to collagen-coated PCL films. Results suggested that surface chemistry has more impact on WJMSCs behaviour rather than topography. In conclusion, collagen-coated electrospun PCL have potential for being used in neural tissue engineering because of its bioactive and three-dimensional structure which enhance viability and differentiation of WJMSCs. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 218-226, 2016. PMID:26265047

  6. 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

  7. 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 ...

  8. Reversible Photoinduced Switching of Permeability in a Cast Non-Porous Film Comprising Azobenzene Liquid Crystalline Polymer.

    PubMed

    Liu, Jian; Wang, Mingle; Dong, Mingling; Gao, Liude; Tian, Jingjing

    2011-07-22

    Permeation characteristics of an azobenzene-containing liquid crystalline (LC) non-porous film are investigated using a metallic corrosion method. Thin films (300?nm) are fabricated by the solution casting of an azobenzene side-chain LC polymer on freshly polished carbon steel coupons. Coated coupons are treated under the following conditions: a) gradual annealing at a cooling rate lower than 1?°C?·?min(-1) from 150?°C (above its T(g) ) to room temperature, and b) irradiation at 465?nm (20 mW?·?cm(-2) ) with either circularly polarized light (CPL) or non-polarized light (NPL). The morphology of these films is characterized using X-ray diffraction, polarized optical microscopy, and transmission measurements. The results suggest that the annealing treatment resulted in the formation of a polydomain structure consisting of locally ordered small smectic domains that lack mutual orientation. Ordered micro domains are surrounded by disordered phases. CPL and NPL irradiation generates a monodomain orientated structure and an isotropic liquid crystal glass, respectively. The permeability of these non-porous films treated by CPL, NPL, and annealing are found to be 6.14?×?10(-4) , 1.92?×?10(-2) , and 1.56?×?10(-3) cm(3) ?·?m(-2) ?·?d(-1) . An orientation-dependent structure model is constructed to explain the permeation phenomenon, considering the ordered phase is impermeable, only the disordered phase is accessible to penetrating molecules. Fast switching of gas permeation is demonstrated by alternative irradiation of the film with CPL and NPL, which results in an approximately 30-fold difference in the permeability of the non-porous film. PMID:21786360

  9. 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

    2015-07-01

    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.

  10. Urinary casts

    MedlinePLUS

    ... tubular epithelial casts; Waxy casts; Casts in the urine; Fatty casts; Red blood cell casts; White blood ... The urine sample you provide may need to be from your first morning urine. The sample needs to be ...

  11. 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)

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

    E-print Network

    Thawonmas, Ruck

    point out a problem in the role casting method of a story generation system called OPIATE system called OPIATE[1][2] ori- ented to online-games. In OPIATE, a story based on the Propp's morphology (NPCs). In an OPIATE's story, a quest is issued to the PC acting as the hero, and NPCs act according

  13. Free-standing films based on silicone resins

    NASA Astrophysics Data System (ADS)

    Katsoulis, Dimitris E.; Suto, Michitaka; Kushibiki, Nobuo

    2003-07-01

    We report here the preparation of transparent, flexible films from silicone resins by solvent casting techniques. The films exhibit no birefringence, higher than 90% transparency between 350 to 1700 nm and average surface roughness below 1 nm. Thermal analysis shows that the films are stable at temperatures greater than 200 °C (depending upon the starting resin composition). The films are suitable substrates for deposition of various coatings including indium tin oxide (ITO). Transparent conducting ITO electrodes were prepared with ion plating and RF sputtering methods and characterized by microscopy, XPS, absorption spectroscopy and electrical conductivity measurements. Potential applications for silicone resin films exist in the market areas of displays, electronics and energy.

  14. 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

  15. 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

  16. Online Measurement for Transient Mold Friction Based on the Hydraulic Oscillators of Continuous-Casting Mold

    NASA Astrophysics Data System (ADS)

    Wang, Xudong; Wang, Zhaofeng; Yao, Man

    2013-12-01

    The interaction of the strand shell surface and mold copper plates has significant effects on the slab surface quality and casting productivity. This article focuses on developing a reliable approach to measure the transient friction force between the slab and the mold for the purpose of the investigation of lubrication and friction behavior inside a mold. This method is presented to monitor transient mold frictions for the slab continuous caster equipped with hydraulic oscillators. A mathematical model is also developed to calculate the empty working force of the no casting state, and a new algorithm, based on the particle swarm optimization, is proposed to predict the dynamic characteristic parameters of mold oscillation. The results have shown that the method has a sufficient sensitivity to variation, especially to the periodical variation of the mold friction, and it has been identified that the transient mold friction can be used as an effective index with regard to detecting mold oscillation and optimizing the casting parameters for process control. It may lay the practical foundation for the online detection of powder lubrication and the visualization of the continuous-casting mold process.

  17. 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.

  18. SUPPLEMENTAL INFORMATION FOR: Interfacial thermal conductance in spun-cast polymer films and

    E-print Network

    Braun, Paul

    with and without a native oxide. All surfaces were first treated for an hour in piranha solution (3 H2SO4 : 1 H2O2 of films to above the glass transition temperature (150°C) for 4 hours and imaged these samples with AFM of the grafted chains. Brush thicknesses ranged from 5 ­ 75 nm, corresponding to number average molecular weights

  19. Social Network Analysis of the Caste-Based Reservation System in India

    E-print Network

    Iyengar, S R S; Saini, Jaspal Singh

    2015-01-01

    It has been argued that the reservation system in India, which has existed since the time of Indian Independence (1947), has caused more havoc and degradation than progress. This being a popular public opinion, these notions have not been based on any rigorous scientific study or research. In this paper, we revisit the cultural divide among the Indian population from a purely social networks based approach. We study the reservation system in detail, starting from its past and observing its effect on the people. Through a survey, we analyze the variation in behavioural characteristics exhibited towards members of the same caste group versus members from another caste group. We study the distinct cluster formation that takes place in the Indian community, and find that this is largely due to the effect of caste-based homophily. To study the social capital associated with each individual in the backward class, we define a new parameter called social distance. We study the changes that take place with regard to t...

  20. A facile and simple high-performance polydimethylsiloxane casting based on self-polymerization dopamine

    NASA Astrophysics Data System (ADS)

    Chen, Xing; Zhang, Lu-lu; Sun, Jian-hai; Li, Hui; Cui, Da-fu

    2014-09-01

    We present a new and facile method for polydimethylsiloxane (PDMS) casting by dip-coating the master molds in an aqueous solution of dopamine. A poly(dopamine) film formed by self-polymerization of dopamine is used as the surface anti-adhesion coating for PDMS de-molding. Different master molds, such as metal, silicon and PDMS replica, were used to verify the feasibility of this proposed PDMS casting method. The poly(dopamine) coatings at various fabrication conditions were studied by using surface plasmon resonance technology. We found that it is very easy to form repeated poly(dopamine) coatings with similar thicknesses and density at fairly flexible conditions of self-polymerization. The water contact angles of the PDMS master molds and the positive PDMS replicas were studied after the PDMS master molds were immersed in the dopamine coating solution for different times. The de-molding process was then measured by surface plasmon resonance technology. The surface morphology of the master molds and the PDMS replicas were characterized by using scanning electron microscopy and atomic force microscopy. Results demonstrate that the poly(dopamine) coating exhibits a strong release property in the PDMS de-molding process and has good stickiness after PDMS de-molding a dozen times. The package performances of the PDMS replicas were detected and compared by bonding experiments. PDMS replicas after a second round of de-molding present a little higher package performance than that of the PDMS replicas with an anti-sticking agent of silane. The biochemical properties of PDMS replicas were studied through fluorescence immunoassay experiments. The PDMS replicas present similar biochemical properties to the bare PDMS. This biomimetic surface modification method of dopamine for PDMS casting has a great potential for preparing microdevices for various biological and clinical applications.

  1. Origin of stress and enhanced carrier transport in solution-cast organic semiconductor films

    NASA Astrophysics Data System (ADS)

    Cour, Ishviene; Chinta, Priya V.; Schlepütz, Christian M.; Yang, Yongsoo; Clarke, Roy; Pindak, Ron; Headrick, Randall L.

    2013-09-01

    Molecular packing in laterally directed solution deposition is a strong function of variables such as printing speed, substrate temperature, and solution concentration. Knowledge of the ordering mechanisms impacts on the development of new processes and materials for improved electronic devices. Here, we present real-time synchrotron x-ray scattering results combined with optical video microscopy, revealing the stages of ordering during the deposition of organic thin films via hollow capillary writing. Limited long range ordering is observed during the initial crystallization, but it gradually develops over 3-4 s for a range of deposition conditions. Buckling of thin films is typically observed for deposition above room temperature. We infer that compressive stress originates from thermal transients related to solvent evaporation on timescales similar to the development of long range ordering. Under optimized conditions, elimination of cracks and other structural defects significantly improves the average charge carrier mobility in organic field-effect transistors.

  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. 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

  4. 49 CFR 173.183 - Nitrocellulose base film.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 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....

  5. 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....

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

    PubMed

    Süry, P; Semlitsch, M

    1978-09-01

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

  7. 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.

  8. Plasmonic films based on colloidal lithography.

    PubMed

    Ai, Bin; Yu, Ye; Möhwald, Helmuth; Zhang, Gang; Yang, Bai

    2014-04-01

    This paper reviews recent advances in the field of plasmonic films fabricated by colloidal lithography. Compared with conventional lithography techniques such as electron beam lithography and focused ion beam lithography, the unconventional colloidal lithography technique with advantages of low-cost and high-throughput has made the fabrication process more efficient, and moreover brought out novel films that show remarkable surface plasmon features. These plasmonic films include those with nanohole arrays, nanovoid arrays and nanoshell arrays with precisely controlled shapes, sizes, and spacing. Based on these novel nanostructures, optical and sensing performances can be greatly enhanced. The introduction of colloidal lithography provides not only efficient fabrication processes but also plasmonic films with unique nanostructures, which are difficult to be fabricated by conventional lithography techniques. PMID:24321859

  9. 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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  11. 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, Gerg?; 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

  12. 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 ?m 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

  13. 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...

  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 epsilon-martensite phase was determined using X-ray diffractrometry. It was found that the amount of epsilon-martensite increases significantly from 2% for the Laser surface processing to 13% in the as cast specimen, 24% in the annealed specimen, and 51% for the TIG surface processing. Moreover, the corrosion rate in Ringer solution was calculated by applying the Tafel extrapolation method on each alloy condition. The lowest corrosion rate (0.435 microm/year) was achieved in the Laser treated alloy and it is attributed to the lack of appreciable athermal epsilon-martensite. The highest corrosion rate (15.5 microm/year) was found to occur in the TIG treated alloy, which possesses the largest amount of epsilon-martensite. In turn, this suggests that surface modification through melting induces variable amounts of athermal epsilon-martensite in the as-cast Co-Cr-Mo-C alloys. Apparently, rapid solidification of melted surfaces in the Co-alloy is highly effective in modifying the induced amounts of HCP phase, and hence, the exhibited properties.

  15. 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.

  16. [Bone fixation of tumor endoprostheses with cast-on spherules of a cobalt-base alloy].

    PubMed

    Gottsauner-Wolf, F; Plenk, H

    1987-06-01

    Special tumor endoprostheses manufactured from cobalt-base alloy with cast-on globules upon the intramedullary shaft and two paracortical flanges for screw fixation can be stabilized at the ends of long bones without using bone cement. Three such implants, retrieved in clinically stable condition after 3 months (proximal tibia), 5 months (distal humerus), and 13 months (distal femur), were investigated microscopically: new bone was found immediately adjacent to the porous surface structures and the fixation screws in many areas. The contribution of bone fragments originating from the preparation of the implant bed to this bone reaction was extremely slight. On the other hand, fibrous tissue layers and a foreign body reaction were found on the remaining surfaces, which may have been related to the compatibility of the implant material and must therefore be regarded as detrimental for the long-term prognosis concerning the fixation of such implants. PMID:3627796

  17. Fabrication of a zirconia MEMS-based microthruster by gel casting on PDMS soft molds

    NASA Astrophysics Data System (ADS)

    Cheah, K. H.; Khiew, P. S.; Chin, J. K.

    2012-09-01

    A zirconia microelectromechanical-system-based microthruster was fabricated through a newly developed fabrication route. Gel casting of homogenously dispersed zirconia suspension on polydimethylsiloxane soft mold was utilized to replicate the geometries of microthruster design onto a ceramic layer of about 1.2 mm thick. Lamination of the patterned ceramic layer to another flat ceramic layer and subsequent sintering produced the microthruster. Characterizations on the fabricated prototype showed good shape retention on the replicated geometries and good quality of lamination. Shrinkage of about 10-15% was noted after sintering. The current fabrication route is particularly promising for the development of high-performance micropropulsion systems which require their structural material to survive in an extreme environment which is corrosive, of high temperature and highly oxidative.

  18. 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.

  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. 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...

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

    NASA Astrophysics Data System (ADS)

    Abaspour, Saeideh; Cáceres, Carlos H.

    2015-09-01

    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.

  3. A general and robust ray-casting-based algorithm for triangulating surfaces at the nanoscale.

    PubMed

    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

  4. 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.

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

    PubMed

    Sadegh-Hassani, Fatemeh; Mohammadi Nafchi, Abdorreza

    2014-06-01

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

  6. Evaluation of thiouracil-based adhesive systems for bonding cast silver-palladium-copper-gold alloy.

    PubMed

    Yamashita, Miyuki; Koizumi, Hiroyasu; Ishii, Takaya; Furuchi, Mika; Matsumura, Hideo

    2010-09-01

    This study aimed to evaluate the effect of adhesive systems based on a thiouracil monomer on bonding to silver-palladium-copper-gold (Ag-Pd-Cu-Au) alloy (Castwell M.C.12). Disk specimens were cast from the alloy and then air-abraded with alumina. The disks were bonded using six bonding systems selected from four primers and three luting materials. Shear bond strengths were determined both before and after thermocycling. Bond strength varied from 2.7 MPa to 32.0 MPa. Three systems based on a thiouracil monomer (MTU-6) showed durable bonding to the alloy, with post-thermocycling bond strengths of 22.4 MPa for the Metaltite (MTU-6) primer and Super-Bond, a tri-n-butylborane (TBB) initiated resin, 9.0 MPa for the Multi-Bond II resin, and 8.1 MPa for the Metaltite and Bistite II system. It can be concluded that a combination of thiouracil-based primer and TBB initiated resin is effective for bonding Ag-Pd-Cu-Au alloy. PMID:20881333

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

    PubMed

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

    2014-06-01

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

  8. 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.

  9. Grain Selection During Casting Ni-Base, Single-Crystal Superalloys with Spiral Grain Selector

    NASA Astrophysics Data System (ADS)

    Gao, S. F.; Liu, L.; Wang, N.; Zhao, X. B.; Zhang, J.; Fu, H. Z.

    2012-10-01

    The behavior of grain selection in a spiral grain selector during investment casting of a Ni-base, single-crystal (SX) superalloy, DD3, has been investigated by electron backscattered diffraction (EBSD) techniques and optical microscopy. The results indicated that the main function of starter block is to optimize the crystal orientation. During the process of grain selection in spiral passage, the grain near the inner wall of spiral passage was usually selected as the final single crystal. It was found that the dendrites near the inner wall could develop new tertiary dendritic arms that paralleled the primary dendrites from the secondary dendritic arms to overgrow the dendrites far away from the inner wall. The crystal orientation that was examined by X-ray diffraction revealed that (1) the crystal orientation did not change obviously with increasing spiral thickness or angle and (2) the crystal orientation could be optimized by increasing the withdrawal rate and ceramic mold temperature. The influence of pouring temperature on crystal orientation was also discussed.

  10. Biphasic calcium phosphate coating on cobalt-base surgical alloy during investment casting.

    PubMed

    Minouei, H; Meratian, M; Fathi, M H; Ghazvinizadeh, H

    2011-11-01

    The biphasic calcium phosphate (BCP) yields higher bioactivity and efficiency than the Hydroxyapatite (HA) alone. The HA/?-TCP ratio significantly affects BCP bioactivity as well as the extent of BCP resorption. In this study, the BCP coating on ASTM F-75 cobalt base alloy during the investment casting process was investigated. For this purpose, molten metal was poured at 1,470°C into previously coated investment molds preheated to 750, 850, 950, 1,050°C in order to investigate the effect of mold preheating temperatures on coating phase transformations. For in vitro evaluation, samples were immersed in the simulated body fluid (SBF) at 37°C for 4 weeks and characterized by XRD, SEM, EDS, and optical microscopy. The weight percentages of HA and ?-TCP of the specimens were calculated to find that the HA/?-TCP ratio significantly depended on the mold preheating temperature as it caused changes in the dissolution behavior of BCP coating and the bone-like apatite precipitation on coating during in vitro evaluation. PMID:21894538

  11. 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

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

    SciTech Connect

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

    2009-01-01

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

  13. The biocompatibility of a dental Ag-Pd-Cu-Au-based casting alloy and its structural components.

    PubMed

    Niemi, L; Syrjänen, S; Hensten-Pettersen, A

    1985-01-01

    The biocompatibility of type III casting gold alloy, an Ag-Pd-Cu-Au-based dental casting alloy and its two main structural components, a CuPd-rich and an Ag-rich phase, was studied after subcutaneous implantation for 7 weeks in 20 guinea pigs. The Ag-Pd-Cu-Au alloy was surrounded by a capsule of immature collagen with fibroblasts and an increased vascular supply. The CuPd-rich component induced and maintained an acute inflammation with highly vascularized granulation tissue. The tissue reaction to the Ag-rich component and the Au-based alloy was slight. Ten of the guinea pigs were sensitized to PdCl2 prior to the implantation period, but this caused no enhanced tissue reaction, except for an increase in the number of mast cells around three of the alloys. PMID:4066727

  14. 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

  15. Structurally Based Assessment of the Influence of Fluorides on the Characteristics of Continuous Casting Powder Slags

    NASA Astrophysics Data System (ADS)

    Schulz, Tilo; Lychatz, Bernd; Haustein, Nicole; Janke, Dieter

    2013-04-01

    The use of fluorides in continuous casting powder leads to the desired reduction of melting temperature to less than 1573 K (1300 °C) as well as to lowering the viscosity below 10 dPas. With an equilateral use of alkalis, the tendency to form volatile fluorine compounds rises. The effect of these components on the structure of the casting slags can be described with the NBO/T-ratio. Should the full effect of fluorides to be used for structural modification of the slags, the other components have to be inhibited by compound formation so as to prevent them from forming gaseous fluoride. If the fluoride content in the continuous casting slag is represented by means of fluorspar, the influence on the NBO/T-ratio can be described with the impact factor 4.0.

  16. 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.

  17. 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

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

    SciTech Connect

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

    2014-09-30

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

  19. 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

  20. 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 (?-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??C/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.

  1. 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.

  2. Investment casting

    SciTech Connect

    Bidwell, H.T.

    1996-04-01

    Materials and manufacturing technologies for investment casting have made impressive gains over the past several years, resulting in higher productivity, shorter lead times, and superior castings. To improve efficiency, investment casters have applied total quality control methods, new management concepts, and computer controls. Management and production efficiency improvements have been critical factors in maintaining and expanding market share.

  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. 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

  5. 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.

  6. 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.

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

    EPA Science Inventory

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

  8. 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...

  9. 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.

  10. Optical antennas based on coupled nanoholes in thin metal films

    E-print Network

    Loss, Daniel

    ARTICLES Optical antennas based on coupled nanoholes in thin metal films Y. ALAVERDYAN* , B. SEP-optical interactions. Here, we show that the strong interaction between nanoholes in optically thin metal films can chains of nanoholes enables either amplification or almost total suppression of the scattered light

  11. FILM E COPERTURE EDULI CON MATRICI A BASE DI FRUTTA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Films based on pear puree were formed using thermal compression molding. Whey protein isolates and soy protein isolates were added to these films to improve their processing and strength. The effects of pear puree concentration, whey or soy protein concentration, moisture content and sorbitol cont...

  12. 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

  13. Antibacterial activity of optically transparent nanocomposite films based on chitosan or its derivatives and silver nanoparticles.

    PubMed

    Pinto, Ricardo J B; Fernandes, Susana C M; Freire, Carmen S R; Sadocco, Patrizia; Causio, Jessica; Neto, Carlos Pascoal; Trindade, Tito

    2012-02-01

    Colloidal silver nanoparticles (NPs) were prepared using the citrate and borohydride reduction methods and were then investigated as fillers in three matrices: unmodified chitosan, water-soluble chitosan and a N-alkyl chitosan derivative. The nanocomposites were used to prepare cast thin films (9-19 ?m thickness) and characterized for their optical and antimicrobial properties. The optical properties of the materials were adjusted either by varying the Ag NPs content in the films (0.5-3.9% w/w) or by using samples of Ag NPs with distinct particle size distributions. The antibacterial activity towards both Gram-positive (Staphylococcus aureus) and Gram-negative bacteria (Klebsiella pneumoniae and Escherichia coli) was investigated for the various composites. For the unmodified chitosan nanocomposites, the bactericidal effect depended on their Ag content while such an effect was always observed for water-soluble chitosan and N-alkyl chitosan based materials. This research provides a basis for the evaluation of chitosan/silver composites in applications requiring flexible films with tuned optical properties and antimicrobial activity. PMID:22154478

  14. 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

  15. Hair casts

    PubMed Central

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

    2014-01-01

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

  16. 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.

  17. 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

  18. 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).

  19. 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.

  20. Exciton dynamics reveal aggregates with intermolecular order at hidden interfaces in solution-cast organic semiconducting films

    NASA Astrophysics Data System (ADS)

    Wong, Cathy Y.; Cotts, Benjamin L.; Wu, Hao; Ginsberg, Naomi S.

    2015-01-01

    Large-scale organic electronics manufacturing requires solution processing. For small-molecule organic semiconductors, solution processing results in crystalline domains with high charge mobility, but the interfaces between these domains impede charge transport, degrading device performance. Although understanding these interfaces is essential to improve device performance, their intermolecular and electronic structure is unknown: they are smaller than the diffraction limit, are hidden from surface probe techniques, and their nanoscale heterogeneity is not typically resolved using X-ray methods. Here we use transient absorption microscopy to isolate a unique signature of a hidden interface in a TIPS-pentacene thin film, exposing its exciton dynamics and intermolecular structure. Surprisingly, instead of finding an abrupt grain boundary, we reveal that the interface can be composed of nanoscale crystallites interleaved by a web of interfaces that compound decreases in charge mobility. Our novel approach provides critical missing information on interface morphology necessary to correlate solution-processing methods to optimal device performance.

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

    SciTech Connect

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

    1996-09-01

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

  2. 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

    ...records on nitrocellulose-base and cellulose-acetate base film? (a) The nitrocellulose base, a substance akin to gun cotton, is chemically unstable and highly flammable. Agencies must handle nitrocellulose-base film (used in the...

  3. 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.

  4. Electromagnetic casting

    SciTech Connect

    Evans, J.W.; Kageyama, R.; Deepak; Cook, D.P.; Prasso, D.C.; Nishioka, S.

    1995-12-31

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

  5. Excellent dispersion of MWCNTs in PEO polymer achieved through a simple and potentially cost-effective evaporation casting.

    PubMed

    Park, Myounggu; Kim, Hyonny; Youngblood, Jeffrey P; Han, Sang Woo; Verplogen, Eric; Hart, A John

    2011-10-14

    A simple, reliable and potentially cost-effective composite film casting procedure is presented using the evaporation of solvent (water) from a dilute mixture of multiwalled carbon nanotubes (MWCNTs) and polyethylene oxide (PEO) polymer. It is found that the fabrication method develops excellent dispersion of MWCNTs in PEO confirmed by morphology observations, final crystallinity of polymer (amorphous) and a lower percolation threshold (closer to theoretical value) as well as higher electrical conductivity. A film thickness prediction model is derived based upon the fact that final film thickness is mainly dependent upon the dimensions of the casting mold and the loading of the MWCNTs and polymer. This simple model provides important insight that the material loss and the actual density of the base polymer are critical factors making the current casting method truly cost effective and controlling final thickness. PMID:21918300

  6. Magnetic-fluid-based porous squeeze films

    NASA Astrophysics Data System (ADS)

    Prajapati, B. L.

    1995-08-01

    The porous squeeze films, lubricated with a magnetic fluid in a bearing of various geometrical shapes like circular, annular, elliptical, infinitely long rectangular, conical, triangular and truncated conical, in the presence of an externally applied oblique magnetic field, is theoretically analysed. The expressions for lubricant pressure are obtained. A bearing working with magnetic fluid as lubricant has a superior performance to that of an identical bearing working with conventional lubricant.

  7. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

  9. ZnS-nanocrystals/polypyrrole nanocomposite film based immunosensor

    NASA Astrophysics Data System (ADS)

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

    2012-01-01

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

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

    SciTech Connect

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

    2006-04-15

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

  11. 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…

  12. 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.

  13. 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.

  14. 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.

  15. Field emission from graphene based composite thin films

    NASA Astrophysics Data System (ADS)

    Eda, Goki; Emrah Unalan, H.; Rupesinghe, Nalin; Amaratunga, Gehan A. J.; Chhowalla, Manish

    2008-12-01

    Field emission from graphene is challenging because the existing deposition methods lead to sheets that lay flat on the substrate surface, which limits the field enhancement. Here we describe a simple and general solution based method for the deposition of field emitting graphene/polymer composite thin films. The graphene sheets are oriented at some angles with respect to the substrate surface leading to field emission at low threshold fields (˜4V?m-1). Our method provides a route for the deposition of graphene based thin film field emitter on different substrates, opening up avenues for a variety of applications.

  16. 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.

  17. 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.

  18. Development and evaluation of gel-forming ocular films based on xyloglucan.

    PubMed

    Mahajan, Hitendra S; Deshmukh, Sachin R

    2015-05-20

    This study aims at application of xyloglucan, polysaccharide polymer as novel film forming agent for ocular delivery of ciprofloxacin. Ciprofloxacin ocular films were prepared by the solvent casting method using xuloglucan (2%). The prepared formulations were evaluated for thickness, percentage drug content, surface pH, swelling, mechanical strength and in vitro drug release. The films were found to be of uniform thickness (0.20 ± 0.07 ?m). The % drug content in the films was found to be 95.45 ± 0.25%. The cumulative % drug releases from the formulation was 98.85 at the end of 24h. The formulations followed the anomalous transport release mechanism. Ocular irritancy study reveals safety of formulation to ocular mucosa. Thus, this study suggests that xyloglucan can act as a potential film forming polymer for ocular delivery of a ciprofloxacin. PMID:25817665

  19. 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.

  20. 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.

  1. 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) with 784 cases and 523 controls included between March 2003 and December 2008 and (2) the Milan study, a population-based case–control study with 2,117 cases and 2,088 controls selected between December 1993 and December 2010 at the Thrombosis Center, Fondazione IRCCS Ca’ Granda–Ospedale Maggiore Policlinico, Milan, Italy. The full model consisted of 32 predictors, including three genetic factors and six biomarkers. For this model, an AUC of 0.85 (95% CI 0.77–0.92) was found in individuals with plaster cast immobilization of the lower extremity. The AUC for the restricted model (containing 11 predictors, including two genetic factors and one biomarker) was 0.84 (95% CI 0.77–0.92). The clinical model (consisting of 14 environmental predictors) resulted in an AUC of 0.77 (95% CI 0.66–0.87). The clinical model was converted into a risk score, the L-TRiP(cast) score (Leiden–Thrombosis Risk Prediction for patients with cast immobilization score), which showed an AUC of 0.76 (95% CI 0.66–0.86). Validation in the THE-VTE study data resulted in an AUC of 0.77 (95% CI 0.58–0.96) for the L-TRiP(cast) score. Validation in the Milan study resulted in an AUC of 0.93 (95% CI 0.86–1.00) for the full model, an AUC of 0.92 (95% CI 0.76–0.87) for the restricted model, and an AUC of 0.96 (95% CI 0.92–0.99) for the clinical model. The L-TRiP(cast) score resulted in an AUC of 0.95 (95% CI 0.91–0.99). Major limitations of this study were that information on thromboprophylaxis was not available for patients who had plaster cast immobilization of the lower extremity and that blood was drawn 3 mo after the thrombotic event. Conclusions These results show that information on environmental risk factors, coagulation factors, and genetic determinants in patients with plaster casts leads to high accuracy in the prediction of VTE risk. In daily practice, the clinical model may be the preferred model as its factors are most easy to determine, while the model still has good predi

  2. Outdoor degradation of thin film amorphous silicon based PV modules

    NASA Astrophysics Data System (ADS)

    Berov, M.; Ivanov, P.; Tuytuyndziev, N.; Vitanov, P.

    2014-12-01

    One of the main problems in thin film silicon based modules is the deterioration of their performance upon exposure to light. The presented work focuses on a methodology for evaluation of thin-film photovoltaic module degradation behavior under real operating conditions. The outdoor degradation of double junction a-Si:H/a-Si:H modules was investigated using automated measurement setup for a period of two years. A deterioration of the module's maximum power was observed due to the well known Staebler-Wronski effect, which main causes are the decrease of open circuit voltage and the fill factor of the module. The obtained results can be correlated to the technology and construction of the thin film silicon based modules.

  3. 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,...

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

    E-print Network

    Wang, Pingshu

    1995-01-01

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

  5. O on the Crystallization Behavior of Lime-Alumina-Based Mold Flux for Casting High-Al Steels

    NASA Astrophysics Data System (ADS)

    Lu, Boxun; Chen, Kun; Wang, Wanlin; Jiang, Binbin

    2014-08-01

    With the development of advanced high strength steel (AHSS), a large amount of aluminum was added into steels. The reaction between aluminum in the molten steel and silica based mold flux in the continuous-casting process would tend to cause a series of problems and influence the quality of slabs. To solve the above problems caused by the slag-steel reaction, nonreactive lime-alumina-based mold flux system has been proposed. In this article, the effect of Li2O and Na2O on the crystallization behavior of the lime-alumina-silica-based mold flux has been studied by using the single hot thermocouple technology (SHTT) and double hot thermocouple technology (DHTT). The results indicated that Li2O and Na2O in the above mold flux system play different roles as they behaved in traditional lime-silica based mold flux, which would tend to inhibit general mold flux crystallization by lowering the initial crystallization temperature and increasing incubation time, especially in the high-temperature region. However, when their content exceeds a critical value, the crystallization process of mold fluxes in low temperature zone would be greatly accelerated by the new phase formation of LiAlO2 and Na x Al y Si z O4 crystals, respectively. The crystalline phases precipitated in all samples during the experiments are discussed in the article.

  6. Ultrathin calix(n)arene-based Langmuir-Blodgett films for gas separations

    NASA Astrophysics Data System (ADS)

    Hendel, Robert Ashley

    Gas separation composite membranes consisting of ultrathin amphiphilic calix[n]arene (C[n]A) monolayers deposited on highly permeable poly[1-(trimethylsilyl)-1-propyne] (PTMSP) support were fabricated and characterized. A series of calix[n]arene-based surfactants was studied, which consisted of various number of units in the macrocycle (e.g., n = 4, 5 and 6), hydrophilic head groups on the "upper-rim" [e.g., amidoxime (AO), boronic acid and acetyl (MK) head groups] and alkyl chains on the "lower rim" [e.g., n-octyl, n-dodecyl (C12) and n-hexadecyl ( C16) tails]. For purposes of comparison, conventional surfactants such as arachidic acid, stearoamidoxime (SA), heptadecylboronic acid and poly(1-octadecene-co-maleic anhydride) (POM) were also investigated. The surfactants were characterized by determining their monolayer properties at the air-water interface, which included surface pressure-area isotherm and surface viscosity behavior. Composite membranes were fabricated using Langmuir-Blodgett (LB) and self-assembly methods and characterized by He and N2 gas permeation properties, X-ray photoelectron spectroscopy, FTIR spectroscopy, ellipsometry, goniometry and electronic imaging. Composites consisting of LB monolayers of amphiphilic calix[n]arene, polymeric and single straight-chain surfactants on PTMSP cast film exhibit significant, modest and no increases in permeation selectivity as compared to the parent support, respectively; e.g., composites consisting of four LB monolayers of C16C[6]AAO, C12C[6]AAO, C16C[6]AMK, POM and SA on PTMSP and bare PTMSP exhibit He/N2 selectivities of ca. 200, 100, 24, 5, 0.9 and 0.9, respectively. Evidence for the causes of these dramatic differences in properties are reported and discussed. It has been found that important criteria for forming highly gas selective surfactant films include: (1) the individual surfactants must be large enough to span the individual holes of the support and (2) strong intermolecular forces between neighboring calix[n]arenes (e.g., via H-bonding and hydrophobic interactions) are necessary to form tightly-packed and robust LB films. The implications of these results, in terms of the further development of LB films as membranes for gas separations and comparisons between industrial membrane materials are discussed. A LB film of C16C[6]AAO represents the "world's thinnest" membrane separator, achieving high He/N2 selectivity.

  7. 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.

  8. 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 ?m. 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

  9. 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.

  10. Graphene-based hybrid films for plasmonic sensing.

    PubMed

    Zhao, Yuan; Zhu, Yanwu

    2015-09-21

    Graphene, a one-atomic-layer-thick planar sheet of sp(2)-bonded carbon configured in a two-dimensional hexagonal lattice, has attracted considerable research interest with regard to sensing-related applications owing to its extraordinary electronic, optical, chemical, and mechanical properties. Graphene plasmonics may be excited in the mid-infrared-to-terahertz regions with high spatial confinement, low loss, and excellent tunability. Meanwhile, graphene can be utilized to tune the plasmonic properties of conventional metallic nanostructures in the visible and near-infrared regions, allowing it to act as a versatile component in various plasmonic applications. This article reviews the recent progress in graphene-based hybrid films used for plasmonic sensing and detection. We particularly emphasize on the unique roles and advantages of graphene in surface-enhanced Raman scattering (SERS) for bare graphene or graphene-metal hybrid films, and plasmonic refractive index (RI) sensing for graphene-metal or graphene-insulator hybrids, among other plasmonic sensing applications. The preparation of graphene-based hybrid films, their functionalization and signal detection techniques are also reviewed. Finally, the perspectives and current challenges in the use of graphene-based hybrid films for plasmonic sensing are outlined. PMID:26282552

  11. Graphene-based hybrid films for plasmonic sensing

    NASA Astrophysics Data System (ADS)

    Zhao, Yuan; Zhu, Yanwu

    2015-08-01

    Graphene, a one-atomic-layer-thick planar sheet of sp2-bonded carbon configured in a two-dimensional hexagonal lattice, has attracted considerable research interest with regard to sensing-related applications owing to its extraordinary electronic, optical, chemical, and mechanical properties. Graphene plasmonics may be excited in the mid-infrared-to-terahertz regions with high spatial confinement, low loss, and excellent tunability. Meanwhile, graphene can be utilized to tune the plasmonic properties of conventional metallic nanostructures in the visible and near-infrared regions, allowing it to act as a versatile component in various plasmonic applications. This article reviews the recent progress in graphene-based hybrid films used for plasmonic sensing and detection. We particularly emphasize on the unique roles and advantages of graphene in surface-enhanced Raman scattering (SERS) for bare graphene or graphene-metal hybrid films, and plasmonic refractive index (RI) sensing for graphene-metal or graphene-insulator hybrids, among other plasmonic sensing applications. The preparation of graphene-based hybrid films, their functionalization and signal detection techniques are also reviewed. Finally, the perspectives and current challenges in the use of graphene-based hybrid films for plasmonic sensing are outlined.

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

    E-print Network

    Deng, Xunming

    Hot-Wire Deposition of Hydrogenated Nanocrystalline SiGe Films for Thin-Film Si Based Solar Cells equipment producing nc-Si:H based solar cells. Two approaches could be used to reduce the total deposition bandgap absorber in an a-Si/a-SiGe/nc-SiGe(nc- Si) triple-junction solar cell due to its higher optical

  13. Casting materials

    DOEpatents

    Chaudhry, Anil R. (Xenia, OH); Dzugan, Robert (Cincinnati, OH); Harrington, Richard M. (Cincinnati, OH); Neece, Faurice D. (Lyndurst, OH); Singh, Nipendra P. (Pepper Pike, OH)

    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.

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

    NASA Astrophysics Data System (ADS)

    Naik, Gautam

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

  15. 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)

  16. Hybrid Thin Films Based Upon Polyoxometalates-Polymer Assembly

    NASA Astrophysics Data System (ADS)

    Qi, Na; Jing, Benxin; Zhu, Yingxi

    2014-03-01

    Block copolymers (BCPs) and polyoxometalates (POMs) have been used individually as building blocks for design and synthesis of novel functional materials. POM nanoclusters, the assemblies of transition metal oxides with well-defined atomic coordination structure, have been recently explored as novel nanomaterials... for catalysis, semiconductors, and even anti-cancer treatment due to their unique chemical, optical and electrical characteristics. We have explored the blending of inorganic POM nanocluster with BCPs into hierarchaically structured inorganic-organic hybrid nanocomposites. Using polystyrene-b-poly(ethylene oxide) (PS-b-PEO) thin films as the template, we have observed that the spatial organization of BCP thin films is modified by molybdenum based POM nanocluster to form 2D in-plane hexagonal ordered or 3D ordered network of POM-BCP assemblies, depending on the concentration ratio of POM to PS-b-PEO. The dielectric properties of such hybrid thin films can be enhanced by embedded POMs but show a strong dependence on the supramolecular structures of POM-polymer complexes. The assembly of nanoclusters in BCP-templated thin films could pave a new path to design new hybrid nanocomposites with uniquely combined functionality and material properties.

  17. 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

  18. 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.

  19. 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.

  20. 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.

  1. 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

  2. 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.

  3. Thin film organic magnet based on vanadium methyl tricyanoethylenecarboxylate

    NASA Astrophysics Data System (ADS)

    Lu, Yu; Harberts, Megan; Kao, Chi-Yueh; Yu, Howard; Epstein, Arthur; Johnston-Halperin, Ezekiel

    2014-03-01

    We report a new organic magnetic thin film based on vanadium and methyl tricyanoethylene carboxylate (MeTCEC) prepared by low temperature chemical vapor deposition (CVD). The magnetic ordering temperature, Tc, is above 300K and x-ray spectroscopy reveals the composition of the thin film is V[MeTCEC]2. IR spectroscopy shows both cyano-vandium and carboxylate-vanadium bonding confirming the predicted chemical structure. The temperature dependence of the magnetization reveals spin glass behavior in the thin film below a blocking temperature of 190K. The hysteresis reveals a soft ferrimagnet with coercive field of 10 Oe at 5 K and 20 Oe at 300 K, respectively. Finally transport measurements show semiconducting behavior with an activation energy of 0.56 eV, consistent with the expected bandgap. Taken together, these properties reveal significant potential for a new class of semiconducting organic-based magnetic materials that complement the existing library of M[TCNE] compounds (where M = V, Co, Fe, Mn). Supported by NSF grant DMR-1207243.

  4. 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.

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

    PubMed Central

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

    2014-01-01

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

  6. 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.

  7. Structure and properties of biomedical films prepared from aqueous and acidic silk fibroin solutions.

    PubMed

    Rajkhowa, Rangam; Levin, Brett; Redmond, Sharon L; Li, Lu Hua; Wang, Lijing; Kanwar, Jagat R; Atlas, Marcus D; Wang, Xungai

    2011-04-01

    Silk fibroin films are promising materials for a range of biomedical applications. To understand the effects of casting solvents on film properties, we used water (W), formic acid (FA), and trifluoroacetic acid (TFA) as solvents. We characterized molecular weight, secondary structure, mechanical properties, and degradation behavior of cast films. Significant degradation of fibroin was observed for TFA-based film compared to W and TA-based films when analyzed by SDS-PAGE. Fibroin degradation resulted in a significant reduction in tensile strength and modulus of TFA-based films. Compared to water, TFA-based films demonstrated lower water solubility (19.6% vs. 62.5% in 12 h) despite having only a marginal increase in their ?-sheet content (26.9% vs. 23.7%). On the other hand, FA-based films with 34.3% ?-sheet were virtually water insoluble. Following solubility treatment, ?-sheet content in FA-based films increased to 50.9%. On exposure to protease XIV, water-annealed FA-based films lost 74% mass in 22 days compared to only 30% mass loss by ethanol annealed FA films. This study demonstrated that a small variation in the ?-sheet percentage and random coil conformations resulted in a significant change in the rates of enzymatic degradation without alteration to their tensile properties. The film surface roughness changed with the extent of enzymatic hydrolysis. PMID:21308983

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

    PubMed

    Amar, Abdurazaq; Parisi, Alfio V

    2013-11-01

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

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

    PubMed Central

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

    2011-01-01

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

  10. Study of carbon nanotubes based Polydimethylsiloxane composite films

    NASA Astrophysics Data System (ADS)

    Shahzad, M. I.; Giorcelli, M.; Shahzad, N.; Guastella, S.; Castellino, M.; Jagdale, P.; Tagliaferro, A.

    2013-06-01

    Thanks to their remarkable characteristics, carbon nanotubes (CNTs) have fields of applications which are growing every day. Among them, the use of CNTs as filler for polymers is one of the most promising. In this work we report on Polydimethylsiloxane (PDMS) composites with different weight percentages (0.0% to 3.0%) of multiwall carbon nanotubes (MWCNTs) having diameter 10-30 nm and length 20-30 ?m. To achieve optimum dispersion of CNTs in PDMS matrix, high speed mechanical stirring and ultrasonication were performed. By using the doctor blade technique, 70 ?m thick uniform films were produced on glass. They were subsequently thermally cured and detached from the glass to get flexible and self standing films. The surface morphological study done by FESEM, shows that CNTs are well dispersed in the PDMS. Raman spectroscopy and FTIR were used to investigate the possible structural changes in the polymer composite. To examine the optical behavior UV-VIS spectroscopy was employed in both specular and diffused modes. A linear increase in absorption coefficient is found with the increasing percentage of CNTs while the transmittance decreases exponentially. The results confirm the dependence of optical limiting effect on the quantity of MWCNTs. Based on optical study, MWCNTs/PDMS composite films can be a promising material to extend performances of optical limiters against laser pulses, which is often required in lasing systems.

  11. Laccase biosensors based on mercury thin film electrode.

    PubMed

    Kirgöz, Ulkü Anik; Tural, Hüseyin; Timur, Suna; Pazarlioglu, Nurdan; Telefoncu, Azmi; Pilloton, Roberto

    2005-01-01

    A biosensor was developed by immobilizing laccase onto mercury thin film electrode (MTFE) by means of gelatin that is then crosslinked with glutaraldehyde. Mercury thin film (MTF) was deposited onto glassy carbon electrode (GCE) and the obtained biosensor was utilized for the determination of phenolic compounds. The measurement was based on the amperometric detection of oxygen consumption in relation to analyte oxidation. The optimum experimental conditions for the biosensor were investigated and the system was calibrated for both catechol and phenol. A linear relationship between sensor responses and analyte concentrations was obtained in concentration range between 0.5 x 10(-6)-5.0 x 10(-6)M for catechol and 2.5 x 10(-6)-2.0 x 10(-6)M for phenol, respectively. Mercury thin film was also formed onto the surface of screen printed graphite electrodes and applied for the catechol detection. The linearity was observed in concentration range between 2.5 x 10(-6)-3.0 x 10(-5)M. PMID:16317963

  12. 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...

  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. Biodegradability and mechanical properties of starch films from Andean crops.

    PubMed

    Torres, F G; Troncoso, O P; Torres, C; Díaz, D A; Amaya, E

    2011-05-01

    Different Andean crops were used to obtain starches not previously reported in literature as raw material for the production of biodegradable polymers. The twelve starches obtained were used to prepare biodegradable films by casting. Water and glycerol were used as plasticizers. The mechanical properties of the starch based films were assessed by means of tensile tests. Compost tests and FTIR tests were carried out to assess biodegradability of films. The results show that the mechanical properties (UTS, Young's modulus and elongation at break) of starch based films strongly depend on the starch source used for their production. We found that all the starch films prepared biodegrade following a three stage process and that the weight loss rate of all the starch based films tested was higher than the weight loss rate of the cellulose film used as control. PMID:21300087

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

    NASA Astrophysics Data System (ADS)

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

    2014-03-01

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

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

    PubMed

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

    2014-03-14

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

  17. 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

  18. 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.

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

    SciTech Connect

    Pankiw, Roman I; Muralidharan, G.; Sikka, Vinod K.

    2006-06-30

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

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

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

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

  1. Yield Improvement in Steel Casting (Yield II)

    SciTech Connect

    Richard A. Hardin; Christoph Beckermann; Tim Hays

    2002-02-18

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

  2. 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.

  3. 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.

  4. 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.

  5. 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.

  6. 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.

  7. Laminating Polyimide Films

    NASA Technical Reports Server (NTRS)

    St. Clair, A. K.; St. Clair, T. L.; Robinson, P. D.

    1983-01-01

    Thermoplastic polyimide adhesive is used to bond polyimide sheets into flexible laminates. Films are first primed with polyimide adhesive, then bonded together under heat and pressure. Adhesive is cast on separate surface, then sandwiched between polyimide and/or metal films for final assembly. Objectives of process are to improve bonding of high-temperature polyimide film, prepare flexible, large-area, void-free laminates from polyimide film, and laminate polyimide film not only to itself but to metal surfaces.

  8. 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.

  9. 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.

  10. Gating of Permanent Molds for Aluminum Casting

    SciTech Connect

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

    2004-01-01

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

  11. Color-Mood Analysis of Films Based on Syntactic and Psychological Models Cheng-Yu Wei

    E-print Network

    Chang, Shih-Fu

    Color-Mood Analysis of Films Based on Syntactic and Psychological Models Cheng-Yu Wei Electrical and browsing. Based on film theories and psychological models, color-mood is an important factor affecting user emotional preferences. We propose a compact set of features for color-mood analysis and subgenre

  12. 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.

  13. 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. 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. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr34304a

  14. 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; Dvo?á?ková, Kate?ina; 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

  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 high-temperature polyimide, and increase the doping rate of indicator dye. All these improvements are expected to bring sensitivity to 10 ppm of ammonia per one full oscillation of signal independent on the humidity of ambient air. The proposed sensor can be used as a robust and inexpensive stand-alone instrument for continuous environment pollution monitoring.

  16. 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.

  17. 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.

  18. 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

  19. 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.

  20. 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.

  1. 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.

  2. 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.

  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. 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

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

    PubMed

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

    2014-09-15

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

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

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  7. 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.

  8. 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.

  9. Improving Metal Casting Process

    NASA Technical Reports Server (NTRS)

    1998-01-01

    Don Sirois, an Auburn University research associate, and Bruce Strom, a mechanical engineering Co-Op Student, are evaluating the dimensional characteristics of an aluminum automobile engine casting. More accurate metal casting processes may reduce the weight of some cast metal products used in automobiles, such as engines. Research in low gravity has taken an important first step toward making metal products used in homes, automobiles, and aircraft less expensive, safer, and more durable. Auburn University and industry are partnering with NASA to develop one of the first accurate computer model predictions of molten metals and molding materials used in a manufacturing process called casting. Ford Motor Company's casting plant in Cleveland, Ohio is using NASA-sponsored computer modeling information to improve the casting process of automobile and light-truck engine blocks.

  10. 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.

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

    E-print Network

    Deng, Xunming

    High Efficiency Thin Film CdTe and a-Si Based Solar Cells Annual Technical Report for the Period-film solar cells and on high efficiency a-Si-based thin-film solar cells. The effort on CdTe- based materials year include the following: · Comparatively studied the performance of a-SiGe solar cells

  12. 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

  13. The effects of samarium addition on CoCrTa-based thin films for magnetic recording

    NASA Astrophysics Data System (ADS)

    Chandrasekhar, R.; Mapps, D. J.

    1996-03-01

    CoCrTa and CoCrTaSm sandwich films were deposited using rf sputtering on glass slides with an underlayer of platinum and a CoNbFe base layer. The films were deposited at room temperature. The magnetic properties and microstructures of the films are reported. The main result is that the addition of small quantities of samarium can increase the perpendicular coercivity from 350 to 1250 Oe. This makes the films more suitable for high-density magnetic recording.

  14. 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.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

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

  16. Water-Soluble Thin Film Transistors and Circuits Based on Amorphous Indium-Gallium-Zinc Oxide

    E-print Network

    Rogers, John A.

    Water-Soluble Thin Film Transistors and Circuits Based on Amorphous Indium-Gallium-Zinc Oxide Sung for amorphous indium-gallium-zinc oxide (a-IGZO) thin film transistors (TFTs) comprised completely of water. INTRODUCTION Research in recent years has established amorphous indium- gallium-zinc oxide (a

  17. 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 ...

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

    PubMed

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

    2015-06-01

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

  19. 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.

  20. 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.

  1. TiNi-based thin films for MEMS applications

    E-print Network

    Fu, Yongqing

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

  2. Homogenization studies for optical sensors based on sculptured thin films 

    E-print Network

    Jamaian, Siti Suhana

    2013-07-01

    In this thesis we investigate theoretically various types of sculptured thin film (STF) envisioned as platforms for optical sensing. A STF consists of an array of parallel nanowires which can be grown on a substrate using ...

  3. Atomic beam deposition of lanthanum- and yttrium-based oxide thin films for gate dielectrics

    NASA Astrophysics Data System (ADS)

    Guha, S.; Cartier, E.; Gribelyuk, M. A.; Bojarczuk, N. A.; Copel, M. C.

    2000-10-01

    We report on the electrical and microstructural characteristics of La- and Y-based oxides grown on silicon substrates by ultrahigh vacuum atomic beam deposition, in order to examine their potential as alternate gate dielectrics for Si complementary metal oxide semiconductor technology. We have examined the issues of polycrystallinity and interfacial silicon oxide formation in these films and their effect on the leakage currents and the ability to deposit films with low electrical thickness. We observe that polycrystallinity in the films does not result in unacceptably high leakage currents. We show significant Si penetration in both types of films. We find that the interfacial SiO2 is much thicker at ˜1.5 nm for the Y-based oxide compared to the La-based oxide where the thickness is <0.5 nm. We also show that while the Y-based oxide films show excellent electrical properties, the La based films exhibit a large flat band voltage shift indicative of positive charge in the films.

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

    NASA Astrophysics Data System (ADS)

    Calixto, Sergio; Montes-Perez, Areli

    2014-07-01

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

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

    PubMed

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

    2015-06-01

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

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

    DOEpatents

    Kapur, Vijay K. (Tarzana, CA); Basol, Bulent M. (Manhattan Beach, CA); Leidholm, Craig R. (Woodland Hills, CA); Roe, Robert A. (Glendale, CA)

    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.

  7. 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...

  8. Neutron radiography inspection of investment castings.

    PubMed

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

    2004-10-01

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

  9. 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.

  10. Engineering Al-based Thin Film Materials for Power Devices and Energy Storage Applications

    E-print Network

    Perng, Ya-Chuan

    2012-01-01

    rod or nanowire battery thus this work focuses on coatingin this work as the electrolyte material for on-chip batterywork to synthesize these Al-based thin film materials for power devices and battery

  11. Millimeter wave phase shifter based on ferromagnetic resonance in a hexagonal barium ferrite thin film

    E-print Network

    Millimeter wave phase shifter based on ferromagnetic resonance in a hexagonal barium ferrite thin of an M-type barium ferrite BaM thin film prepared by pulsed laser deposition and a coplanar waveguide

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

    E-print Network

    Smyth, Katherine Marie

    2012-01-01

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

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

    NASA Astrophysics Data System (ADS)

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

    2013-09-01

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

  14. Fabrication of porous beta-tricalcium phosphate with microchannel and customized geometry based on gel-casting and rapid prototyping.

    PubMed

    Li, X; Bian, W; Li, D; Lian, Q; Jin, Z

    2011-03-01

    The tissue engineering scaffolds with three-dimensional porous structure are regarded to be beneficial to facilitate a sufficient supply of nutrients and enable cell ingrowth in bone reconstruction. However, the pores in scaffolds tend to be blocked by the cell ingrowth and result in a restraint of nutrient supply in the further side of the scaffold. An indirect approach of combining the rapid prototyping and gel-casting technique is introduced in this study to fabricate beta-tricalcium phosphate (beta-TCP) scaffolds which not only have interconnected porous structure, but also have a microchannel network inside. The scaffold was designed with customized geometry that matches the defect area, and a double-scale (micropores-microchannel) porous structure inside that is beneficial for cell ingrowth. The scaffolds fabricated have an open, uniform, and interconnected porous architecture with a pore size of 200-400 microm, and posses an internal channel network with a diameter of 600 microm. The porosity was controllable. The compressive yield strength was 4.5 MPa with a porosity of 70 per cent. X-ray diffraction analysis shows that these fabrication processes do not change the crystal structure and chemical composition of beta-TCP. With this technique, it was also possible to fabricate porous scaffolds with desired pore size, porosity, and microchannel, as well as customized geometries by other bioceramics. PMID:21485332

  15. 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

  16. 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.

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

    E-print Network

    Deng, Xunming

    High Efficiency Thin Film CdTe and a-Si Based Solar Cells Final Technical Report for the PeriodTe-based thin-film solar cells and on high efficiency a-Si-based thin-film solar cells. Phases I and II have and Phase III are: Phase I: · Established a base line for the fabrication of a-Si based solar cells

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

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

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

  19. 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.

  20. Radiation dose dependent change in physiochemical, mechanical and barrier properties of guar gum based films.

    PubMed

    Saurabh, Chaturbhuj K; Gupta, Sumit; Bahadur, Jitendra; Mazumder, S; Variyar, Prasad S; Sharma, Arun

    2013-11-01

    Mechanical and water vapor barrier properties of biodegradable films prepared from radiation processed guar gum were investigated. Films prepared from GG irradiated up to 500 Gy demonstrated significantly higher tensile strength as compared to non-irradiated control films. This improvement in tensile strength observed was demonstrated to be due to the ordering of polymer structures as confirmed by small angle X-ray scattering analysis. Exposure to doses higher than 500 Gy, however, resulted in a dose dependent decrease in tensile strength. A dose dependent decrease in puncture strength with no significant differences in the percent elongation was also observed at all the doses studied. Water vapor barrier properties of films improved up to 15% due to radiation processing. Radiation processing at lower doses for improving mechanical and barrier properties of guar based packaging films is demonstrated here for the first time. PMID:24053847

  1. 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

  2. Dry Process Based Infrared Sensors with CNT Film Absorber

    NASA Astrophysics Data System (ADS)

    Yoo, Kum-Pyo; Hong, Hyun Pyo; Lim, Lee-Taek; Choi, Chang-Seon; Lee, Dong Il; Lee, Cheol Jin; Park, Chan-Won; Min, Nam Ki

    In this paper, we describe the fabrication and characterization of a front-side micromachined thermopiles consisting of a suspended membrane and a carbon nanotube (CNT) film absorber. Thermocouples of 52 pairs which are composed of phosphorous-doped silicon and aluminum were formed and connected in series. A CNT film collected by filter was transferred on hot junction. A CNT absorber has an absorptance of about 50% in the midinfrared region. The suspended membrane was fabricated by an isotropic silicon dry etching process with XeF2 gas at the front side of the substrates. The output voltage with the CNT film is found to be 250.2 mV at 7 mW of incident power, approximately 1.8 times higher than that of one without an absorber.

  3. 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-distributed single hit model based on physical assumptions. Three-channel dosimetry was found to be substantially superior to red-channel dosimetry. Conclusions: Reflection mode with Gafchromic EBT2 radiochromic film was found to be a viable alternative to transmission mode. The same methods that are used in transmission mode can be followed in reflection mode. A novel plan-based method was developed for calibration and multichannel dosimetry. This novel method offers increased robustness against film response inhomogeneities and reduces considerably the time required for calibration.

  4. 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.

  5. Mango and acerola pulps as antioxidant additives in cassava starch bio-based film.

    PubMed

    Souza, Carolina O; Silva, Luciana T; Silva, Jaff R; López, Jorge A; Veiga-Santos, Pricila; Druzian, Janice I

    2011-03-23

    The objective of this study was to investigate the feasibility of incorporating mango and acerola pulps into a biodegradable matrix as a source of polyphenols, carotenoids, and other antioxidant compounds. We also sought to evaluate the efficacy of mango and acerola pulps as antioxidants in film-forming dispersions using a response surface methodology design experiment. The bio-based films were used to pack palm oil (maintained for 45 days of storage) under accelerated oxidation conditions (63% relative humidity and 30 °C) to simulate a storage experiment. The total carotenoid, total polyphenol, and vitamin C contents of films were evaluated, while the total carotenoid, peroxide index, conjugated diene, and hexanal content of the packaged product (palm oil) were also monitored. The same analysis also evaluated palm oil packed in films without antioxidant additives (C1), palm oil packed in low-density polyethylene films (C2), and palm oil with no package (C3) as a control. Although the film-forming procedure affected the antioxidant compounds, the results indicated that antioxidants were effective additives for protecting the packaged product. A lower peroxide index (36.12%), which was significantly different from that of the control (p<0.05), was detected in products packed in film formulations containing high concentration of additives. However, it was found that the high content of vitamin C in acerola pulp acted as a prooxidant agent, which suggests that the use of rich vitamin C pulps should be avoided as additives for films. PMID:21361289

  6. Characterization of edible emulsified films with low affinity to water based on kefiran and oleic acid.

    PubMed

    Ghasemlou, Mehran; Khodaiyan, Faramarz; Oromiehie, Abdulrasoul; Yarmand, Mohammad Saeid

    2011-10-01

    New edible composite films based on kefiran and oleic acid (OA) at the ratio of 15, 25, and 35% (w/w) were prepared using emulsification with the aim of improving their water vapour barrier and mechanical properties. Film-forming solutions were characterized in terms of rheological properties and particle-size distribution. The impact of the incorporation of OA into the film matrix was studied by investigating the physical, mechanical, and thermal properties of the films. The water vapour permeability (WVP) of the emulsified films was reduced by approximately 33% by adding OA. The mechanical properties of kefiran films were also affected by adding OA: tensile strength was diminished, and elongation increased considerably. Differential scanning calorimetry showed that the glass transition temperature (T(g)) of the kefiran film was -16°C and was not considerably affected by adding OA. Therefore, OA could be incorporated into these films for some food-technology applications that need a low affinity toward water. PMID:21640752

  7. 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.

  8. 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.

  9. 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 ?-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).

  10. 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.

  11. Hot film anemometry. Citations from the NTIS data base

    NASA Astrophysics Data System (ADS)

    Habercom, G. E., Jr.

    1980-08-01

    The principles of hot film anemometer operation are summarized; wind tunnel and laboratory tests are described; flow field dynamics are discussed involving turbulence, boundary layers, separation, shock waves, and stresses; mathematical models and analysis are presented; computer techniques are outlined; and a number of applications are given. This updated bibliography contains 58 citations, 3 of which are new entries to the previous edition.

  12. Production and characterization of films from cotton stalk xylan.

    PubMed

    Goksu, Emel I; Karamanlioglu, Mehlika; Bakir, Ufuk; Yilmaz, Levent; Yilmazer, Ulku

    2007-12-26

    Composite film production based on cotton stalk xylan was studied, and the mechanical and physical properties of the films formed were investigated. Xylan and lignin were separated from cellulose by alkali extraction and, then, lignin was removed using ethanol washing. Self-supporting continuous films could not be produced using pure cotton stalk xylan. However, film formation was achieved using 8-14% (w/w) xylan without complete removal of lignin during xylan isolation. Keeping about 1% lignin in xylan (w/w) was determined to be sufficient for film formation. Films were produced by casting the film-forming solutions, followed by solvent evaporation in a temperature (20 degrees C) and relative humidity (40%) controlled environment. The elastic modulus and hypothetical coating strength of the films obtained by using 8% xylan were significantly different from the ones containing 10-14% xylan. The water vapor transfer rates (WVTR) decreased with increasing xylan concentration, which made the films thicker. The glycerol addition as an additional plasticizer resulting in more stretchable films having higher WVTR and lower water solubility values. As a result, film production was successfully achieved from xylan, which was extracted from an agricultural waste (cotton stalk), and the film-forming effect of lignin on pure xylan has been demonstrated. PMID:18038981

  13. Elevated temperature mechanical properties and residual tensile properties of two cast superalloys and several nickel-base oxide dispersion strengthened alloys

    NASA Technical Reports Server (NTRS)

    Whittenberger, J. D.

    1981-01-01

    The elevated temperature tensile, stress-rupture and creep properties and residual tensile properties after creep straining have been determined for two cast superalloys and several wrought Ni-16Cr-4Al-yttria oxide dispersion strengthened (ODS) alloys. The creep behavior of the ODS alloys is similar to that of previously studied ODS nickel alloys. In general, the longitudinal direction is stronger than the long transverse direction, and creep is at least partially due to a diffusional creep mechanism as dispersoid-free zones were observed after creep-rupture testing. The tensile properties of the nickel-base superalloy B-1900 and cobalt-base superalloy MAR-M509 are not degraded by prior elevated temperature creep straining (at least up to 1 pct) between 1144 and 1366 K. On the other hand, the room temperature tensile properties of ODS nickel-base alloys can be reduced by prior creep strains of 0.5 pct or less between 1144 and 1477 K, with the long transverse direction being more susceptible to degradation than the longitudinal direction.

  14. 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.

  15. 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 deliver to industry a computer program in which all three systems are coupled for determining the dimensions of the wax pattern, the shell mold, and casting in a sequential but coupled manner.

  16. Large oriented arrays and continuous films of TiO(2)-based nanotubes.

    PubMed

    Tian, Zhengrong R; Voigt, James A; Liu, Jun; McKenzie, Bonnie; Xu, Huifang

    2003-10-15

    We report for the first time a one-step, templateless method to directly prepare large arrays of oriented TiO2-based nanotubes and continuous films. These titania nanostructures can also be easily prepared as conformal coatings on a substrate. The nanostructured films were formed on a Ti substrate seeded with TiO2 nanoparticles. SEM and TEM results suggested that a folding mechanism of sheetlike structures was involved in the formation of the nanotubes. The oriented arrays of TiO2 nanotubes, continuous films, and coatings are expected to have potentials for applications in catalysis, filtration, sensing, photovoltaic cells, and high surface area electrodes. PMID:14531662

  17. Rheological properties of pullulan-sodium alginate based solutions during film formation.

    PubMed

    Xiao, Qian; Tong, Qunyi; Zhou, Yujia; Deng, Fangming

    2015-10-01

    During film formation, the rheological properties of pullulan, sodium alginate, and blends, dried at 50°C were studied using an oscillatory rheometer. According to the drying curves, the drying process of pullulan, alginate, and blend films was divided into three stages. At the first drying stage, four samples exhibited typical liquid-like viscoelastic behavior. As the drying proceeded (polysaccharide concentration up to 75%), pure pullulan chains formed an entangled network, whereas coupling of alginate molecules gave a weak gel. At this drying stage, complex viscosity data for 75% alginate and blends were fitted with the power law equation. The effects of drying on the mechanical properties of pullulan-sodium alginate based samples were analyzed using the generalized Maxwell model, and their relaxation spectra were determined. The rheological properties during drying obtained from this study is essential for understanding film-forming mechanism and predicting the properties of pullulan-sodium alginate based edible films. PMID:26076600

  18. Thin films prepared by simultaneous deposition of copper and free-base phthalocyanine

    NASA Astrophysics Data System (ADS)

    Fejfar, A.; Takaoka, G.; Yamada, I.

    1993-09-01

    Composite films of metals and dielectrics attracted considerable attention in the past for their novel optical and mechanical properties which can be tailored precisely by changing their structure and composition. In this work we present a probe into a related but hitherto unexplored field of composites where metal is combined with molecular semiconductor. As model materials we chose free-base phthalocyanine and copper. Films were prepared by simultaneous deposition of copper and free-base phthalocyanine in the dual ICB system. An answer to two basic questions was sought after: 1) does the copper combine with freebase phthalocyanine to form a copper phthalocyanine complex, 2) what is the structure of the films if there is non-stoichiometric surplus of copper in the films? We report results of structural study by a transmission electron microscope. Optical behaviour of the composite was characterized by optical reflectance and transmittance measurement in UV/VIS/NIR range and complemented by FT IR spectra.

  19. 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.

  20. Synthesis and Electrochemical Behavior of Ceria Based Bi-Layer Films by Dip Coating Technique.

    PubMed

    Chinnu, M Karl; Anand, K Vijai; Kumar, R Mohan; Alagesan, T; Jayavel, R

    2015-01-01

    Ceria based bi-layer films of CeO2-CdS and CeO2-TiO2 were prepared by sol-gel based hydrothermal route combined with dip-coating. The synthesized samples were subjected to various characterizations such as X-ray diffraction, Field emission scanning electron microscopy, thermo-gravimetric analysis, UV-Vis absorption and photoluminescence studies. The prepared materials were dissolved in naffion solution and disposed as a thin film on glassy carbon electrode by dip coating technique. Electrochemical Li+ intercalation/deintercalation was performed by cyclic voltammetry and these results indicate that the CeO2/LiClO4 system is electrochemically reversible. The total intercalation/deintercalation of the CeO2 film, CeO2-CdS and CeO2-TiO2 bi-layer films was determined by cyclic voltammetry, which showed increased charge storage capacity. PMID:26328361

  1. Photoluminescence-based quality control for thin film absorber layers of photovoltaic devices

    DOEpatents

    Repins, Ingrid L.; Kuciauskas, Darius

    2015-07-07

    A time-resolved photoluminescence-based system providing quality control during manufacture of thin film absorber layers for photovoltaic devices. The system includes a laser generating excitation beams and an optical fiber with an end used both for directing each excitation beam onto a thin film absorber layer and for collecting photoluminescence from the absorber layer. The system includes a processor determining a quality control parameter such as minority carrier lifetime of the thin film absorber layer based on the collected photoluminescence. In some implementations, the laser is a low power, pulsed diode laser having photon energy at least great enough to excite electron hole pairs in the thin film absorber layer. The scattered light may be filterable from the collected photoluminescence, and the system may include a dichroic beam splitter and a filter that transmit the photoluminescence and remove scattered laser light prior to delivery to a photodetector and a digital oscilloscope.

  2. Method of casting aerogels

    DOEpatents

    Poco, John F. (Livermore, CA)

    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.

  3. 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.

  4. Improved unipolar resistive switching characteristics of mixed-NiOx/NiOy-film-based resistive switching memory devices

    NASA Astrophysics Data System (ADS)

    Liu, Lifeng; Hou, Yi; Chen, Bing; Gao, Bin; Kang, Jinfeng

    2015-09-01

    A mixed-NiOx/NiOy-film-based unipolar-type resistive switching memory device is proposed and fabricated. Mixed NiOx/NiOy films were prepared by two-step film deposition followed by furnace annealing. Mixed phases of Ni2O3 and NiO coexist across the mixed NiOx/NiOy films. Compared with a single-NiOy-film-based memory device, the mixed-NiOx/NiOy-film-based memory device shows improved unipolar resistive switching performances, including high ON/OFF ratio, sufficient operation voltage window, and good endurance characteristics. The improved memory performance could be attributed to the effect of oxygen-rich NiOx with more oxygen-rich Ni2O3, which can supply sufficient oxygen ions (O2-) for resistive switching in mixed-NiOx/NiOy-film-based resistive random access memory (RRAM) devices.

  5. 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.

  6. 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

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

    DOEpatents

    Johnson, Robert Alan (Simpsonville, SC); Schaeffer, Jon Conrad (Greenville, SC); Lee, Ching-Pang (Cincinnati, OH); Abuaf, Nesim (Lincoln City, OR); Hasz, Wayne Charles (Pownal, VT)

    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.

  8. An Iron-based Film for Highly Efficient Electrocatalytic Oxygen Evolution from Neutral Aqueous Solution.

    PubMed

    Chen, Mingxing; Wu, Yizhen; Han, Yongzhen; Lin, Xiaohuan; Sun, Junliang; Zhang, Wei; Cao, Rui

    2015-10-01

    An ultrathin Fe-based film was prepared by electrodeposition from an Fe(II) solution through a fast and simple cyclic voltammetry method. The extremely low Fe loading of 12.3 nmol cm(-2) on indium tin oxide electrodes is crucial for high atom efficiency and transparence of the resulted film. This Fe-based film was shown to be a very efficient electrocatalyst for oxygen evolution from neutral aqueous solution with remarkable activity and stability. In a 34 h controlled potential electrolysis at 1.45 V (vs NHE) and pH 7.0, impressive turnover number of 5.2 × 10(4) and turnover frequency of 1528 h(-1) were obtained. To the best of our knowledge, these values represent one of the highest among electrodeposited catalyst films for water oxidation under comparable conditions. The morphology and the composition of the catalyst film was determined by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray, and X-ray photoelectron spectroscopy, which all confirmed the deposition of Fe-based materials with Fe(III) oxidation state on the electrode. This study is significant because of the use of iron, the fast and simple cyclic voltammetry electrodeposition, the extremely low catalyst loading and thus the transparency of the catalyst film, the remarkable activity and stability, and the oxygen evolution in neutral aqueous media. PMID:26368828

  9. Evaluation and improvement in the accuracy of a charge-coupled-device-based pyrometer for temperature field measurements of continuous casting billets.

    PubMed

    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. PMID:23822369

  10. 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.

  11. Tape casting of lanthanum chromite

    SciTech Connect

    Murphy, M.W.; Armstrong, T.R.; Smith, P.A.

    1997-01-01

    Solid oxide fuel cells (SOFCs) are currently being developed for a variety of applications such as stationary on-site power plants and cogeneration. The effects of process additives, ball milling, and solids loading were evaluated for tape casting suspensions of glycine-nitrate-synthesized La{sub 0.7}Ca{sub 0.31}CrO{sub 3} powder. An optimized formulation was obtained based on rheological characterization, electrokinetic sonic amplitude measurements, qualitative examination of green tapes, and the sintered microstructure. The tape casting formulation incorporated 66:34 methyl ethyl ketone/ethyl alcohol solvent, an aliphatic phosphate ester dispersant, and 80 wt% (35 vol%) solids. The best binder/plasticizer system was 12 wt% (15 vol%) poly(isobutyl methacrylate) and 5 wt% (6.3 vol%) benzyl butyl phthalate plasticizer (binder:plasticizer = 2.3). Cast tapes were sintered at 1300 C for 2 h, producing a bulk density of 96.2% theoretical, with linear shrinkage of 22% and an approximate grain size of 1.3 {micro}m.

  12. Physical Simulation of Investment Casting of Complex Shape Parts

    NASA Astrophysics Data System (ADS)

    Rahimian, Mehdi; Milenkovic, Srdjan; Maestro, Laura; De Azua, Aitor Eguidazu Ruiz; Sabirov, Ilchat

    2015-05-01

    Development of investment casting process has been a challenge for manufacturers of complex shape parts. Numerous experimental casting trials are typically carried out to determine the optimum casting parameters for fabrication of high-quality products. In this work, it is demonstrated that physical simulation of investment casting can successfully predict microstructure and hardness in as-cast complex shape parts. The physical simulation tool consists of a thermal model and melting/solidification experiments in thermo-mechanical simulator. The thermal model is employed to predict local cooling rate during solidification at each point of a casting. Melting/solidification experiments are carried out under controlled cooling rates estimated by the thermal model. Microstructural and mechanical characterization of the solidified specimens is performed; the obtained results predict the local microstructure and mechanical properties of the casting. This concept is applied to investment casting of complex shape nozzle guide vanes from Mar-M247 Ni-based superalloy. Experimental casting trials are performed and the outcomes of physical simulation tool are validated against experimental results. It is shown that phase composition, secondary dendrite arm spacing, grain size, ?/ ?' eutectic size and volume fraction, size and shape of carbide particles, and local microhardness can be predicted at each point of the casting via physical simulation.

  13. Mimetic marine antifouling films based on fluorine-containing polymethacrylates

    NASA Astrophysics Data System (ADS)

    Sun, Qianhui; Li, Hongqi; Xian, Chunying; Yang, Yihang; Song, Yanxi; Cong, Peihong

    2015-07-01

    Novel methacrylate copolymers containing catechol and trifluoromethyl pendant side groups were synthesized by free radical polymerization of N-(3,4-dihydroxyphenyl)ethyl methacrylamide (DMA) and 2,2,2-trifluoroethyl methacrylate (TFME) with ?,??-azobisisobutyronitrile (AIBN) as initiator. A series of copolymers with different content of TFME ranging from 3% to 95% were obtained by changing the molar ratio of DMA to TFME from 25:1 to 1:25. Fourier transform infrared (FT-IR) spectroscopy, gel permeation chromatography (GPC), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM) were used to characterize the copolymers, which displayed a certain degree of hardness and outstanding thermostability reflected from their high glass transition temperatures. The copolymers could adhere to surfaces of glass, plastics and metals due to introduction of catechol groups as multivalent hydrogen bonding anchors. Water contact angle on the polymer films was up to 117.4°. Chemicals resistance test manifested that the polymer films possessed excellent resistance to water, salt, acid and alkali. Moreover, the polymer films displayed fair antifouling property and might be used as promising environmentally friendly marine antifouling coatings.

  14. Tunable permalloy-based films for magnonic devices

    NASA Astrophysics Data System (ADS)

    Yin, Yuli; Pan, Fan; Ahlberg, Martina; Ranjbar, Mojtaba; Dürrenfeld, Philipp; Houshang, Afshin; Haidar, Mohammad; Bergqvist, Lars; Zhai, Ya; Dumas, Randy K.; Delin, Anna; Åkerman, Johan

    2015-07-01

    Using both broadband ferromagnetic resonance (FMR) spectroscopy and ab initio calculations, we study the magnetodynamic properties of permalloy (Py,Ni80Fe20) and Py100 -xMx films with M as platinum (Pt), gold (Au), or silver (Ag). From the uniform FMR mode, we extract the saturation magnetization (MS), damping (? ), and inhomogeneous broadening (? H0) ; from the first perpendicular standing spin-wave (PSSW) mode, we extract the exchange stiffness (A ). MS and A are found to decrease with increasing alloying, most strongly for Au and less so for Pt. On the other hand, ? increases rapidly with both Pt and Au content, while being virtually independent of Ag content. The physical origins of the observed trends in ? , MS, and A are analyzed and explained using density functional theory calculations in the coherent potential approximation. The calculated trends quantitatively agree with the experimental observations. The drastically different impacts of Pt, Au, and Ag on the various fundamental magnetodynamic properties will allow for significant design freedom, where different properties can be varied independently of others through careful combinations of the Pt, Au, and Ag contents of Py100 -xMx films. By empirical approximations of each property's concentration dependence, we can dial in any desired combination of magnetodynamic properties within this parameter space. As a proof-of-principle demonstration we design a set of Py100 -x -yPtxAgy films, where the saturation magnetization stays constant throughout the set and the damping can be tuned by a factor of 4.

  15. Bio-based biodegradable film to replace the standard polyethylene cover for silage conservation.

    PubMed

    Borreani, Giorgio; Tabacco, Ernesto

    2015-01-01

    The research was aimed at studying whether the polyethylene (PE) film currently used to cover maize silage could be replaced with bio-based biodegradable films, and at determining the effects on the fermentative and microbiological quality of the resulting silages in laboratory silo conditions. Biodegradable plastic film made in 2 different formulations, MB1 and MB2, was compared with a conventional 120-?m-thick PE film. A whole maize crop was chopped; ensiled in MB1, MB2, and PE plastic bags, 12.5kg of fresh weight per bag; and opened after 170d of conservation. At silo opening, the microbial and fermentative quality of the silage was analyzed in the uppermost layer (0 to 50mm from the surface) and in the whole mass of the silo. All the silages were well fermented with little differences in fermentative quality between the treatments, although differences in the mold count and aerobic stability were observed in trial 1 for the MB1 silage. These results have shown the possibility of successfully developing a biodegradable cover for silage for up to 6mo after ensiling. The MB2 film allowed a good silage quality to be obtained even in the uppermost part of the silage close to the plastic film up to 170d of conservation, with similar results to those obtained with the PE film. The promising results of this experiment indicate that the development of new degradable materials to cover silage till 6mo after ensiling could be possible. PMID:25468689

  16. 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 diameter, which corresponds to the size of a dime as viewed from about two and a half miles. Illustration of Crab, Titan's Shadow and Chandra Illustration of Crab, Titan's Shadow and Chandra Unlike almost all of Chandra's images which are made by focusing X-ray emission from cosmic sources, Titan's X-ray shadow image was produced in a manner similar to a medical X-ray. That is, an X-ray source (the Crab Nebula) is used to make a shadow image (Titan and its atmosphere) that is recorded on film (Chandra's ACIS detector). Titan's atmosphere, which is about 95% nitrogen and 5% methane, has a pressure near the surface that is one and a half times the Earth's sea level pressure. Voyager I spacecraft measured the structure of Titan's atmosphere at heights below about 300 miles (500 kilometers), and above 600 miles (1000 kilometers). Until the Chandra observations, however, no measurements existed at heights in the range between 300 and 600 miles. Understanding the extent of Titan's atmosphere is important for the planners of the Cassini-Huygens mission. The Cassini-Huygens spacecraft will reach Saturn in July of this year to begin a four-year tour of Saturn, its rings and its moons. The tour will include close flybys of Titan that will take Cassini as close as 600 miles, and the launching of the Huygens probe that will land on Titan's surface. Chandra's X-ray Shadow of Titan Chandra's X-ray Shadow of Titan "If Titan's atmosphere has really expanded, the trajectory may have to be changed." said Tsunemi. The paper on these results has been accepted and is expected to appear in a June 2004 issue of The Astrophysical Journal. Other members of the research team were Haroyoski Katayama (Osaka University), David Burrows and Gordon Garmine (Penn State University), and Albert Metzger (JPL). Chandra observed Titan from 9:04 to 18:46 UT on January 5, 2003, using its Advanced CCD Imaging Spectrometer instrument. NASA's Marshall Space Flight Center, Huntsville, Ala., manages the Chandra program for the Office of Space Science, NASA Headquarters,

  17. Morphology of Microscopic Thin Rubber Films

    NASA Astrophysics Data System (ADS)

    Zhang, Xin; Briber, Robert; Wang, Howard

    2014-03-01

    Microscopic thin rubber films have been prepared using photolithographic methods. Thin films of low molecular weight polybutadiene have been spun cast on positive photoresists, and transferred to various substrates upon UV exposure for crosslinking and defining the lateral dimension. The morphological scaling of thin rubber films as a function of film dimension and temperature is discussed.

  18. Methodology for cost analysis of film-based and filmless portable chest systems

    NASA Astrophysics Data System (ADS)

    Melson, David L.; Gauvain, Karen M.; Beardslee, Brian M.; Kraitsik, Michael J.; Burton, Larry; Blaine, G. James; Brink, Gary S.

    1996-05-01

    Many studies analyzing the costs of film-based and filmless radiology have focused on multi- modality, hospital-wide solutions. Yet due to the enormous cost of converting an entire large radiology department or hospital to a filmless environment all at once, institutions often choose to eliminate film one area at a time. Narrowing the focus of cost-analysis may be useful in making such decisions. This presentation will outline a methodology for analyzing the cost per exam of film-based and filmless solutions for providing portable chest exams to Intensive Care Units (ICUs). The methodology, unlike most in the literature, is based on parallel data collection from existing filmless and film-based ICUs, and is currently being utilized at our institution. Direct costs, taken from the perspective of the hospital, for portable computed radiography chest exams in one filmless and two film-based ICUs are identified. The major cost components are labor, equipment, materials, and storage. Methods for gathering and analyzing each of the cost components are discussed, including FTE-based and time-based labor analysis, incorporation of equipment depreciation, lease, and maintenance costs, and estimation of materials costs. Extrapolation of data from three ICUs to model hypothetical, hospital-wide film-based and filmless ICU imaging systems is described. Performance of sensitivity analysis on the filmless model to assess the impact of anticipated reductions in specific labor, equipment, and archiving costs is detailed. A number of indirect costs, which are not explicitly included in the analysis, are identified and discussed.

  19. Preparation and properties of carboxymethyl cellulose/layered double hydroxide bionanocomposite films.

    PubMed

    Yadollahi, Mehdi; Namazi, Hassan; Barkhordari, Soroush

    2014-08-01

    Solution casting method was employed for preparing of carboxymethyl cellulose/layered double hydroxide (CMC-LDH) bionanocomposite films with LDH content ranged from 0 to 8 wt%. The synthesized nanocomposite films were characterized using FTIR, XRD, TEM and SEM analytical methods. XRD and TEM analysis revealed a partially exfoliated structure for nanocomposites with LDH content up to 3 wt%. However, for LDH contents higher than 3 wt%, nanocomposites formed an intercalated structure. Incorporation of LDH significantly decreased water vapor permeability (WVP) of the bionanocomposite films up to 37%. Addition of the LDHs into the CMC matrix is accompanied by a decrease in the film transparency. Mechanical properties of CMC-based films were improved significantly by addition of LDH particles. CMC-LDH nanocomposite film with 3 wt% LDH showed a 148 and 143% increase in the tensile strength and tensile modulus, as well as a 62% decrease in elongation in comparison with the pure CMC film. PMID:24751250

  20. Effect of oil lamination between plasticized starch layers on film properties.

    PubMed

    Basiak, Ewelina; Debeaufort, Frédéric; Lenart, Andrzej

    2016-03-15

    To reduce the hygroscopic character of biodegradable starch-based films, rapeseed oil was incorporated by lamination (starch-oil-starch 3-layers technique). The lipid lamination followed by starch solution casting step induced an emulsion type structure of dried films. Composite films are more opalescent and glossier than fatty free starch films. For all the films, structure is heterogeneous in the cross-section only. Adding fat induced a twice decrease of the tensile strength. Thermal gravimetry analysis did not show differences between films with and without oil. Lipid reduced the moisture absorption particularly at higher RH as well as the surface swelling index, when water droplet contact occurred. Addition of lipids always decreases the contact angle for all liquid tested, except for water. Surface affinity of films for liquids less polar that water increased with rapeseed oil addition. The addition of rapeseed oil significantly reduces water vapour and oxygen permeability. PMID:26575712

  1. Poster — Thur Eve — 20: CTDI Measurements using a Radiochromic Film-based clinical protocol

    SciTech Connect

    Quintero, C.; Bekerat, H.; DeBlois, F.; Tomic, N.; Devic, S.; Seuntjens, J.

    2014-08-15

    The purpose of the study was evaluating accuracy and reproducibility of a radiochromic film-based protocol to measure computer tomography dose index (CTDI) as a part of annual QA on CT scanners and kV-CBCT systems attached to linear accelerators. Energy dependence of Gafchromic XR-QA2 ® film model was tested over imaging beam qualities (50 – 140 kVp). Film pieces were irradiated in air to known values of air-kerma (up to 10 cGy). Calibration curves for each beam quality were created (Film reflectance change Vs. Air-kerma in air). Film responses for same air-kerma values were compared. Film strips were placed into holes of a CTDI phantom and irradiated for several clinical scanning protocols. Film reflectance change was converted into dose to water and used to calculate CTDIvol values. Measured and tabulated CTDIvol values were compared. Average variations of ±5.2% in the mean film reflectance change were observed in the energy range of 80 to 140 keV, and 11.1% between 50 and 140 keV. Measured CTDI values were in average 10% lower than tabulated CTDI values for CT-simulators, and 44% higher for CBCT systems. Results presented a mean variation for the same machine and protocol of 2.6%. Variation of film response is within ±5% resulting in ±15% systematic error in dose estimation if a single calibration curve is used. Relatively large discrepancy between measured and tabulated CTDI values strongly support the trend towards replacing CTDI value with equilibrium dose measurement in the center of cylindrical phantom, as suggested by TG- 111.

  2. Large third-order nonlinear refractive index coefficient based on gold nanoparticle aggregate films

    NASA Astrophysics Data System (ADS)

    Bai, Songang; Li, Qiang; Zhang, Han; Chen, Xingxing; Luo, Si; Gong, Hanmo; Yang, Yuanqing; Zhao, Ding; Qiu, Min

    2015-10-01

    Au nanoparticles show large third-order nonlinear effect and ultra-fast response. Here a high nonlinear aggregate film based on self-assembled gold nanoparticles is reported and its third-order nonlinear refractive index coefficient is measured by Z-scan experiment. The third-order nonlinear refractive index coefficient of the Au nanoparticle aggregate film (?1 = 9.2 × 10-9 cm2/W) is found to be larger than that of an 8-nm-thick sputtered Au film (?2 = 6.5 × 10-9 cm2/W). This large nonlinear effect can be attributed to the strong field enhancement due to localized plasmon resonances between Au nanoparticles. The result shows that the self-assembled Au nanoparticle aggregate film could be a promising candidate as a third-order nonlinear optical material.

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

    SciTech Connect

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

    2015-05-15

    We report the structural and optical properties of thermally evaporated Bi{sub 2}Te{sub 3}, In{sub 2}Te{sub 3} and InBiTe{sub 3} films by using X-ray diffraction, optical and Raman Spectroscopy techniques. The as-prepared thin films were found to be Semi-crystalline by X-ray diffraction. Particle Size and Strain has been calculated from XRD data. The optical constants, film thickness, refractive index and optical band gap (E{sub g}) has been reported for In{sub 2}Te{sub 3}, InBiTe{sub 3} films. Raman Spectroscopy was performed to investigate the effect of Bi, In, on lattice vibration and chemical bonding in Te based chalcogenide glassy alloys.

  4. Tunable electrical conductivity in oriented thin films of tetrathiafulvalene-based covalent organic framework

    SciTech Connect

    Cai, SL; Zhang, YB; Pun, AB; He, B; Yang, JH; Toma, FM; Sharp, ID; Yaghi, OM; Fan, J; Zheng, SR; Zhang, WG; Liu, Y

    2014-09-16

    Despite the high charge-carrier mobility in covalent organic frameworks (COFs), the low intrinsic conductivity and poor solution processability still impose a great challenge for their applications in flexible electronics. We report the growth of oriented thin films of a tetrathiafulvalene-based COF (TTF-COF) and its tunable doping. The porous structure of the crystalline TTF-COF thin film allows the diffusion of dopants such as I-2 and tetracyanoquinodimethane (TCNQ) for redox reactions, while the closely packed 2D grid sheets facilitate the cross-layer delocalization of thus-formed TTF radical cations to generate more conductive mixed-valence TTF species, as is verified by UV-vis-NIR and electron paramagnetic resonance spectra. Conductivity as high as 0.28 S m(-1) is observed for the doped COF thin films, which is three orders of magnitude higher than that of the pristine film and is among the highest for COF materials.

  5. Evaluation of a CCD-based film digitizer for digital mammography

    NASA Astrophysics Data System (ADS)

    Kallergi, Maria; Gavrielides, Marios A.; Gross, William W.; Clarke, Laurence P.

    1997-05-01

    Film digitalization is the process of mapping the optical densities of a radiographic film into a digital matrix. In this work, a film digitizer based on charge-coupled device was evaluated and optimized for digital mammography applications. The characteristics of the digital output were determined for various spatial resolutions and dynamic ranges. Furthermore, the reproducibility of the system was tested as needed for computer assisted diagnosis (CAD) applications. Practical and relevant to the application quality control procedures were established for the system that will allow early troubleshooting and close monitoring of image quality for consistent performance. Overall, the characteristics of the scanner matched the properties of the tested screen/films and its performance generally met digital mammography and CAD requirements.

  6. Affective Realism of Animated Films in the Development of Simulation-Based Tutoring Systems

    ERIC Educational Resources Information Center

    Ekanayake, Hiran B.; Fors, Uno; Ramberg, Robert; Ziemke, Tom; Backlund, Per; Hewagamage, Kamalanath P.

    2013-01-01

    This paper presents a study focused on comparing real actors based scenarios and animated characters based scenarios with respect to their similarity in evoking psychophysiological activity for certain events by measuring galvanic skin response (GSR). In the experiment, one group (n = 11) watched the real actors' film whereas another group (n…

  7. High energy-density 0.72Pb(Zr0.47Ti0.53)O3-0.28Pb[(Zn0.45Ni0.55)1/3Nb2/3]O3 thick films fabricated by tape casting for energy-harvesting-device applications

    NASA Astrophysics Data System (ADS)

    Jeon, Chang Jun; Hwang, Ha Na; Jeong, Young Hun; Yun, Ji Sun; Nam, Joong Hee; Cho, Jeong Ho; Paik, Jong Hoo; Lim, Jong Bong; Nahm, Sahn; Kim, Eung Soo

    2013-11-01

    0.72Pb(Zr0.47Ti0.53)O3-0.28Pb[(Zn0.45Ni0.55)1/3Nb2/3]O3 (0.72PZT-0.28PZNN) thick films were prepared by using a tape casting method to develop new materials with high energy-density applicable to energy-harvesting devices. The piezoelectric strain constant ( d 33), dielectric constant ( ? {33/ T }/ ? 0), piezoelectric voltage constant ( g 33) and transduction coefficient ( d 33· g 33) of the films were affected by the sintering temperature. These results could be attributed to the crystal structure, microstructures and secondary phases. However, the dielectric loss (tan ?) of the films was not changed remarkably with increasing sintering temperature. Typically, a d 33 of 452 pC/N, ? {33/ T }/ ? 0 of 1444, d 33· g 33 of 20,340 × 10-15 m2/N and tan ? of 0.15% were obtained for the films sintered at 1050 °C for 1 h. The power generation performance of the piezoelectric unimorph cantilever was assessed to demonstrate the feasibility of the 0.72PZT-0.28PZNN piezoelectric thick film. Also, theoretical models were employed to predict the resonance frequency of the unimorph cantilever generator, and the predicted values were compared with experimental data.

  8. 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 ?m in diameter, is a challenging task. An established protocol uses corrosion casts and applies synchrotron radiation-based micro-computed tomography (SR?CT), which provides the desired spatial resolution with the necessary contrast. However, SR?CT 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 SR?CT, 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.

  9. Architectural optimization of an epoxy-based hybrid sol-gel coating for the corrosion protection of a cast Elektron21 magnesium alloy

    NASA Astrophysics Data System (ADS)

    Murillo-Gutiérrez, N. V.; Ansart, F.; Bonino, J.-P.; Kunst, S. R.; Malfatti, C. F.

    2014-08-01

    An epoxy-based hybrid sol-gel coating was prepared in various architectural configurations has been studied for the corrosion protection of a cast Elektron21 magnesium alloy. The creation of a single layer of this coating presents defects consisting of macro-pores and protuberances, which opens access for corrosive species to reach the metallic substrate. These defects are suspected to result from the high reactivity of the substrate, as well as to the irregular topography of the substrate disrupted by the microstructure of the own magnesium alloy. Hence, a sol-gel coating in bilayer architecture is proposed, where the first layer would “inert” the surface of the magnesium substrate, and the second layer would cover the defects of the first layer and also thickening the coating. The morphological characteristics of the sol-gel coatings were analyzed by scanning electron microscopy (SEM), and their corrosion behavior was evaluated by OCP (open circuit potential) monitoring and electrochemical impedance spectroscopy (EIS) in chloride media. It is shown that both the architectural arrangement and the individual thickness of the first and second layers have an important influence on the anticorrosion performances of the protective system, just as much as its global thickness.

  10. Informing Selection of Nanomaterial Concentrations for ToxCast In Vitro Testing based on Occupational Exposure Potential

    EPA Science Inventory

    Little justification is generally provided for selection of in vitro assay testing concentrations for engineered nanomaterials (ENMs). Selection of concentration levels for hazard evaluation based on real-world exposure scenarios is desirable. We reviewed published ENM concentr...

  11. Enhanced gold film-coupled graphene-based plasmonic nanosensor

    NASA Astrophysics Data System (ADS)

    Nicolas, R.; Maurer, T.; Lévêque, G.; Subramanian, P.; Proust, J.; Béal, J.; Schuermans, S.; Vilcot, J.-P.; Herro, Z.; Kazan, M.; Plain, J.; Boukherroub, R.; Akjouj, A.; Djafari-Rouhani, B.; Adam, P.-M.; Szunerits, S.

    2013-09-01

    In this work, a trilayer graphene is used as a thin non dielectric spacer with a high index of refraction, between Au film and Au NPs. Encouraged by the sharpness of the localized surface plasmon resonance LSPR induced by this system, we performed sensitivity measurements to refractive index change in the surrounding medium of the sensor. The presence of graphene led to both higher sensitivity and sharper full width at half maximum FWHM and thus higher figure of merit FOM (2.8) compared to the system without graphene (2.1).

  12. A piezo-film-based measurement system for global haemodynamic assessment.

    PubMed

    Clemente, Fabrizio; Arpaia, Pasquale; Cimmino, Pasquale

    2010-05-01

    A non-invasive piezo-film-based measurement method for haemodynamic assessment is proposed. The design of a system, able to reconstruct the blood pressure waveform online by dealing with problems arising from the piezo-film capacitive nature in the targeted frequency range (from quasi-dc up to 12 Hz), is illustrated. The system is based on a commercial piezo-film placed easily on the radial artery with a special brace without any discomfort for the patient. The analogical conditioning circuit and digital signal processing are continuously tuned with the signal from the sensor to reconstruct the blood pressure signal online. Diagnostic schema, based on physio-pathological models, have been implemented in order to compute online trends of max[dP(t)/d(t)] and volemic status highly useful for the intensivist and anaesthesiologist. The system was characterized by numerical simulation and experimental in vivo comparison to the traditional reference system. PMID:20395651

  13. Comparison of photovoltaic performance of TiO2 nanoparticles based thin films via different routes

    NASA Astrophysics Data System (ADS)

    Ji, Yajun

    2015-11-01

    Well crystallized TiO2 nanoparticles were prepared by hydrothermal and sol-gel routes, respectively. The morphologies, structures, crystallinity and optical properties of resulted TiO2 nanoparticles-based thin films via the two methods were examined by field emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD) and reflectance spectra. In addition, comparison of photovoltaic performance of TiO2 nanoparticles-based thin films by the two methods was performed. It is found that the maximum energy conversion efficiency of 4.06% was achieved based on the obtained electrode via hydrothermal, which is much better than that of the sol-gels route. The uniform film structure with improved dye absorption capability, increased diffused reflectance property and relatively low charge recombination rates for injected electrons are believed to be responsible to the superior photoelectrochemical properties of dye-sensitized solar cells (DSSC) via hydrothermal route.

  14. Acid diffusion through polymer films

    NASA Astrophysics Data System (ADS)

    Zhang, P. Linda; Eckert, Andrew R.; Willson, C. Grant; Webber, Stephen E.; Byers, Jeffrey D.

    1997-07-01

    In order to perform 0.2 micrometer processes, one needs to study the diffusion of photoacid generators within the photoresist system, since diffusion during post exposure bake time has an influence on the critical dimension (CD). We have developed a new method to study the diffusion of photoacid generators within a polymer film. This new method is based on monitoring the change of the fluorescence intensity of a pH- sensitive fluorescent dye caused by the reaction with photoacid. A simplified version of this experiment has been conducted by introducing acid vapor to quench the fluorescence intensity of this pH sensor. A thin polymer film is spin cast onto the sensor to create a barrier to the acid diffusion process. During the acid diffusion process, the fluorescence intensity of this pH sensor is measured in situ, using excitation and emission wavelengths at 466 nm and 516 nm, respectively. Fluoresceinamine, the pH sensitive fluorescent dye, is covalently bonded onto the treated quartz substrate to form a single dye layer. Poly(hydroxystyrene) (Mn equals 13k, Tg equals 180 degrees Celsius) in PGMEA (5% - 18% by weight) is spin cast onto this quartz substrate to form films with varying thickness. The soft bake time is 60 seconds at 90 degrees Celsius and a typical film has a thickness of 1.4 micrometers. Trifluoroacetic acid is introduced into a small chamber while the fluorescence from this quartz window is observed. Our study focuses on finding the diffusion constant of the vaporized acid (trifluoroacetic acid) in the poly(hydroxystyrene) polymer film. By applying the Fick's second law, (It - Io)/(I(infinity ) - Io) equals erfc [L/(Dt)1/2] is obtained. The change of fluorescence intensity with respect to the diffusion time is monitored. The above equation is used for the data analysis, where L represents the film thickness and t represents the average time for the acid to diffuse through the film. The diffusion constant is calculated to be at the order of 10-10 cm2/s to 10-12 cm2/s. All the experiments are conducted at room temperature and are valid only for acid vapor. With different film thickness, it was found that the acid diffuses through the film with a similar diffusion constant. The diffusion is faster with increased solvent residue in the film (controlled by spin coating speed). The theoretical computer modeling of the local acid concentration with respect to acid diffusion is also performed.

  15. Growth characteristics of Ti-based fumaric acid hybrid thin films by molecular layer deposition.

    PubMed

    Cao, Yan-Qiang; Zhu, Lin; Li, Xin; Cao, Zheng-Yi; Wu, Di; Li, Ai-Dong

    2015-09-01

    Ti-based fumaric acid hybrid thin films were successfully prepared using inorganic TiCl4 and organic fumaric acid as precursors by molecular layer deposition (MLD). The effect of deposition temperature from 180 °C to 350 °C on the growth rate, composition, chemical state, and topology of hybrid films has been investigated systematically by means of a series of analytical tools such as spectroscopic ellipsometry, atomic force microscopy (AFM), high resolution X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). The MLD process of the Ti-fumaric acid shows self-limiting surface reaction with a reasonable growth rate of ?0.93 Å per cycle and small surface roughness of ?0.59 nm in root-mean-square value at 200 °C. A temperature-dependent growth characteristic has been observed in the hybrid films. On increasing the temperature from 180 °C to 300 °C, the growth rate decreases from 1.10 to 0.49 Å per cycle and the XPS composition of the film's C?:?O?:?Ti ratio changes from 8.35?:?7.49?:?1.00 to 4.66?:?4.80?:?1.00. FTIR spectra indicate that the hybrid films show bridging bonding mode at a low deposition temperature of 200 °C and bridging/bidentate mixed bonding mode at elevated deposition temperatures of 250 and 300 °C. The higher C and O amounts deviating from the ideal composition may be ascribed to increased organic incorporation into the hybrid films at lower deposition temperature and temperature-dependent density of reactive sites (-OH). The composition of hybrid films grown at 350 °C shows a dramatic decrease in C and O elemental composition (C?:?O?:?Ti = 1.97?:?2.76?:?1.00) due to the thermal decomposition of the fumaric acid precursor. The produced by-product H2O changes the structure of the hybrid films, resulting in the formation of more Ti-O bonds at high temperatures. The stability of the hybrid films against chemical and thermal treatment, and long-term storage by vacuum-packing was explored carefully. It is found that the ultrathin hybrid film can be transformed into TiO2 nanoparticles via various post deposition annealing processes with different topographies. Finally, the charge trapping ability of the hybrid film is confirmed by fabricating a charge trapping memory capacitor in which the hybrid film was inserted as a charge trapping layer. PMID:26219386

  16. 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.

  17. Ultrathin Chitosan Films with Tailored Properties

    NASA Astrophysics Data System (ADS)

    Murray, Chris; Stukalov, Oleg; Dutcher, John

    2004-03-01

    Chitosan is a biodegradable polysaccharide derived from seashell waste products. Though abundant, the industrial use of this polymer has up until recently been limited to water treatment products. The high water absorbency and biocompatibility of chitosan have enabled its use as a hydrogel in specialty applications such as wound dressings and drug delivery systems. The most convenient method of processing chitosan is solution casting to form films, since the polymer is soluble in weakly acidic solvents. Based on previous work with synthetic polymers, we have developed a protocol for preparing thin, uniform films of chitosan by spincoating from solution onto silicon substrates. Films with thicknesses between 30 and 600 nm (as measured by ellipsometry) and rms roughnesses of less than 1 nm (as measured by atomic force microscopy) were prepared. After preparation, these films quickly absorb water in the presence of high humidity. Heating of the films to high temperature causes large reductions in film thickness h and index of refraction n. After cooling the films to room temperature, h and n remain constant in the presence of high humidity. Using this simple procedure, we are able to produce films with tailored thickness, optical properties and water absorbency.

  18. Morphogen Electrochemically Triggered Self-Construction of Polymeric Films Based on Mussel-Inspired Chemistry.

    PubMed

    Maerten, Clément; Garnier, Tony; Lupattelli, Paolo; Chau, Nguyet Trang Thanh; Schaaf, Pierre; Jierry, Loïc; Boulmedais, Fouzia

    2015-12-15

    Inspired by the strong chemical adhesion mechanism of mussels, we designed a catechol-based electrochemically triggered self-assembly of films based on ethylene glycol molecules bearing catechol groups on both sides and denoted as bis-catechol molecules. These molecules play the role of morphogens and, in contrast to previously investigated systems, they are also one of the constituents, after reaction, of the film. Unable to interact together, commercially available poly(allylamine hydrochloride) (PAH) chains and bis-catechol molecules are mixed in an aqueous solution and brought in contact with an electrode. By application of defined potential cycles, bis-catechol molecules undergo oxidation leading to molecules bearing "reactive" quinone groups which diffuse toward the solution. In this active state, the quinones react with amino groups of PAH through Michael addition and Schiff's base condensation reaction. The application of cyclic voltammetry (CV) between 0 and 500 mV (vs Ag/AgCl, scan rate of 50 mV/s) of a PAH/bis-catechol solution results in a fast self-construction of a film that reaches a thickness of 40 nm after 60 min. The films present a spiky structure which is attributed to the use of bis-functionalized molecules as one component of the films. XPS measurements show the presence of both PAH and bis-catechol cross-linked together in a covalent way. We show that the amine/catechol ratio is an important parameter which governs the film buildup. For a given amine/catechol ratio, it does exist an optimum CV scan rate leading to a maximum of the film thickness as a function of the scan rate. PMID:26575431

  19. Correlation between macroscopic porosity location and liquid metal pressure in centrifugal casting technique.

    PubMed

    Vaidyanathan, T K; Schulman, A; Nielsen, J P; Shalita, S

    1981-01-01

    Radiographic analysis of uniform cylindrical castings fabricated by the centrifugal casting technique has revealed that the macroscopic porosity is dependent on the location of the sprue attachment to the casting. This is attributed to the significant pressure gradient associated with the centrifugal casting technique. The pressure gradient results in different heat transfer rates at portions of the castings near and away from the free surface of the button. Consequently, the macroscopic porosity is invariably at portions of the casting close to the free surface of the button. In addition, some optimized sprue-reservoir combinations could be predicted and proved, based on this pressure gradient concept. PMID:7002971

  20. Hickey, C8206_all casts Hickey, C8206_all casts, page 1

    E-print Network

    Hickey, Barbara

    Hickey, C8206_all casts Hickey, C8206_all casts, page 1 #12;Hickey, C8206_all casts Hickey, C8206_all casts, page 2 #12;Hickey, C8206_all casts Hickey, C8206_all casts, page 3 #12;Hickey, C8206_all casts Hickey, C8206_all casts, page 4 #12;Hickey, C8206_all casts Hickey, C8206_all casts, page 5 #12

  1. Study of water vapour permeability of protein and gum-based edible films by a photothermal method

    NASA Astrophysics Data System (ADS)

    Tomás, S. A.; Saavedra, R.; Cruz, A.; Pedroza-Islas, R.; San Martín, E.

    2005-06-01

    The water vapour permeability of protein and gum-based edible films was studied by means of a photothermal method. The films were prepared with two basic ingredients, whey protein concentrate and mesquite gum, according to the proportions 75:25, 50:50, 25:75, and 0:100 (weight:weight). The water vapour diffusion coefficient of the analyzed films was found within the interval 0.37 × 10-6 to 2.04 × 10-6 cm^2/s, increasing linearly by increasing the mesquite gum composition in the films. The incorporation of mesquite gum in films produces less effective moisture barriers due to its highly hydrophilic property.

  2. Local Evolution of the Elastocaloric Effect in TiNi-Based Films

    NASA Astrophysics Data System (ADS)

    Ossmer, H.; Chluba, C.; Gueltig, M.; Quandt, E.; Kohl, M.

    2015-06-01

    Strain and temperature profiles of magnetron-sputtered ferroelastic TiNi-based films of 20 ?m thickness are investigated during tensile load cycling with respect to strain, strain rate, and cycle number in order to assess their potential for elastocaloric cooling. Two different ferroelastic film specimens are considered, binary TiNi and quaternary TiNiCuCo films, which strongly differ regarding their phase transformation hysteresis and fatigue behavior. In situ digital image correlation and infrared thermography measurements reveal a correlated response of strain and temperature bands that is determined by mesoscale stress and temperature fields on the kinetics of phase transformation. In the case of binary TiNi films, this response is also strongly affected by cycling-induced fatigue causing vanishing band formation and decreasing elastocaloric effect size. In contrast, TiNiCuCo films show negligible fatigue and retain the local characteristics of the elastocaloric effect. Compared to TiNi films, they exhibit not only a reduced temperature change, but also a reduced work input for pseudoelastic cycling resulting in an improved material's coefficient of performance of 15.

  3. Thin film polarizer and color filter based on photo-polymerizable nematic liquid crystal

    NASA Astrophysics Data System (ADS)

    Mohammadimasoudi, Mohammad; Neyts, Kristiaan; Beeckman, Jeroen

    2015-03-01

    We present a method to fabricate a thin film color filter based on a mixture of photo-polymerizable liquid crystal and chiral dopant. A chiral nematic liquid crystal layer reflects light for a certain wavelength interval ?? (= ?n.P) with the period and ?n the birefringence of the liquid crystal. The reflection band is determined by the chiral dopant concentration. The bandwidth is limited to 80nm and the reflectance is at most 50% for unpolarized incident light. The thin color filter is interesting for innovative applications like polarizer-free reflective displays, polarization-independent devices, stealth technologies, or smart switchable reflective windows to control solar light and heat. The reflected light has strong color saturation without absorption because of the sharp band edges. A thin film polarizer is developed by using a mixture of photo-polymerizable liquid crystal and color-neutral dye. The fabricated thin film absorbs light that is polarized parallel to the c axis of the LC. The obtained polarization ratio is 80% for a film of only 12 ?m. The thin film polarizer and the color filter feature excellent film characteristics without domains and can be detached from the substrate which is useful for e.g. flexible substrates.

  4. IPMC actuators based on metal-Nafion™ composite films prepared by thermal decomposition of noble metal complexes

    NASA Astrophysics Data System (ADS)

    Yang, Kwang Suk; Lee, Hyung-Kun; Choi, Nak-Jin; Jeong, Young Hun; Cho, Jeong Ho; Paik, Jong-Hoo; Yun, Ji Sun

    2015-08-01

    A simple and highly efficient compositing process was developed by synthesizing Pt or Pd nanoparticles embedded in polymers (Nafion™) with uniform distribution by in situ thermal decomposition of noble metal complexes. The homogenous mixtures of the metal complexes ( trans-Pt(DMSO)(NH2CH2CH2OH)Cl2 or trans-Pd(DMSO)(H2NCH2CH2OH)Cl2) and Nafion™ dispersion went through a film casting process, and the metal ions in the Nafion™ were reduced to metal nanoparticles by the annealing process. The in situ compositing method avoids the use of excess metal sources and any external reducing agent/stabilizing agents, and leads to a uniform distribution of nanoparticles in the polymer matrixes. The films were characterized using optical microscopy and scanning electron microscopy. The actuation behavior in response to an AC electric field was investigated by bending displacements and blocking force measurements.

  5. Simulation of Dimensional Changes in Steel Casting

    E-print Network

    Beckermann, Christoph

    Simulation of Dimensional Changes in Steel Casting Shouzhu (Hans) Ou and Christoph Beckermann Pattern allowances in casting of steel are predicted using the casting simulation software MAGMASOFT to predict dimensional changes occurring during solidification and cooling of a steel casting

  6. Disposable urea biosensor based on nanoporous ZnO film fabricated from omissible polymeric substrate.

    PubMed

    Rahmanian, Reza; Mozaffari, Sayed Ahmad; Abedi, Mohammad

    2015-12-01

    In the present study, a facile and simple fabrication method of a semiconductor based urea biosensor was reported via three steps: (i) producing a ZnO-PVA composite film by means of a polymer assisted electrodeposition of zinc oxide (ZnO) on the F-doped SnO2 conducting glass (FTO) using water soluble polyvinyl alcohol (PVA), (ii) obtaining a nanoporous ZnO film by PVA omission via a subsequent post-treatment by annealing of the ZnO-PVA film, and (iii) preparation of a FTO/ZnO/Urs biosensor by exploiting a nanoporous ZnO film as an efficient and excellent platform area for electrostatic immobilization of urease enzyme (Urs) which was forced by the difference in their isoelectric point (IEP). The characterization techniques focused on the analysis of the ZnO-PVA film surfaces before and after annealing, which had a prominent effect on the porosity of the prepared ZnO film. The surface characterization of the nanostructured ZnO film by a field emission-scanning electron microscopy (FE-SEM), exhibited a film surface area as an effective bio-sensing matrix for enzyme immobilization. The structural characterization and monitoring of the biosensor fabrication was performed using UV-Vis, Fourier Transform Infrared (FT-IR), Raman Spectroscopy, Thermogravimetric Analysis (TGA), Cyclic Voltammetry (CV), and Electrochemical Impedance Spectroscopy (EIS) techniques. The impedimetric results of the FTO/ZnO/Urs biosensor showed a high sensitivity for urea detection within 8.0-110.0mg dL(-1) with the limit of detection as 5.0mg dL(-1). PMID:26354280

  7. 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.

  8. Sealing micropores in thin castings

    NASA Technical Reports Server (NTRS)

    Mersereau, G. A.; Nitzschke, G. O.; Ochs, H. L.; Sutch, F. S.

    1981-01-01

    Microscopic pores in thin-walled aluminum castings are sealed by impregnation pretreatment. Technique was developed for investment castings used in hermetically sealed chassic for electronic circuitry. Excessively high leakage rates were previously measured in some chassis.

  9. Schottky Solar Cells Based on Colloidal Nancrystal Films

    SciTech Connect

    Luther, J. M.; Law, M.; Beard, M. C.; Song, Q.; Reese, M. O.; Ellingson, R. J.; Nozik, A. J.

    2008-01-01

    We describe here a simple, all-inorganic metal/NC/metal sandwich photovoltaic (PV) cell that produces an exceptionally large short-circuit photocurrent (>21 mA cm{sup -2}) by way of a Schottky junction at the negative electrode. The PV cell consists of a PbSe NC film, deposited via layer-by-layer (LbL) dip coating that yields an EQE of 55-65% in the visible and up to 25% in the infrared region of the solar spectrum, with a spectrally corrected AM1.5G power conversion efficiency of 2.1%. This NC device produces one of the largest short-circuit currents of any nanostructured solar cell, without the need for sintering, superlattice order or separate phases for electron and hole transport.

  10. Electrodeposition of Zn based nanostructure thin films for photovoltaic applications

    SciTech Connect

    Al-Bat’hi, S. A. M.

    2015-03-30

    We present here a systematic study on the synthesis thin films of various ZnO, CdO, Zn{sub x}Cd{sub 1-x} (O) and ZnTe nanostructures by electrodeposition technique with ZnCl{sub 2,} CdCl{sub 2} and ZnSO{sub 4} solution as starting reactant. Several reaction parameters were examined to develop an optimal procedure for controlling the size, shape, and surface morphology of the nanostructure. The results showed that the morphology of the products can be carefully controlled through adjusting the concentration of the electrolyte. The products present well shaped Nanorods arrays at specific concentration and temperature. UV-VIS spectroscopy and X-ray diffraction results show that the product presents good crystallinity. A possible formation process has been proposed.

  11. Advanced Pattern Material for Investment Casting Applications

    SciTech Connect

    F. Douglas Neece Neil Chaudhry

    2006-02-08

    Cleveland Tool and Machine (CTM) of Cleveland, Ohio in conjunction with Harrington Product Development Center (HPDC) of Cincinnati, Ohio have developed an advanced, dimensionally accurate, temperature-stable, energy-efficient and cost-effective material and process to manufacture patterns for the investment casting industry. In the proposed technology, FOPAT (aFOam PATtern material) has been developed which is especially compatible with the investment casting process and offers the following advantages: increased dimensional accuracy; increased temperature stability; lower cost per pattern; less energy consumption per pattern; decreased cost of pattern making equipment; decreased tooling cost; increased casting yield. The present method for investment casting is "the lost wax" process, which is exactly that, the use of wax as a pattern material, which is then melted out or "lost" from the ceramic shell. The molten metal is then poured into the ceramic shell to produce a metal casting. This process goes back thousands of years and while there have been improvements in the wax and processing technology, the material is basically the same, wax. The proposed technology is based upon an established industrial process of "Reaction Injection Molding" (RIM) where two components react when mixed and then "molded" to form a part. The proposed technology has been modified and improved with the needs of investment casting in mind. A proprietary mix of components has been formulated which react and expand to form a foam-like product. The result is an investment casting pattern with smooth surface finish and excellent dimensional predictability along with the other key benefits listed above.

  12. Depth profiles and free volume in aircraft primer films

    NASA Astrophysics Data System (ADS)

    Van Horn, J. D.; Chen, H.; Jean, Y. C.; Zhang, W.; Jaworowski, M. R.

    2015-06-01

    Positron annihilation lifetime spectroscopy (PALS) and associated techniques provide non-destructive methods to study the free volume inside polymeric materials, and to study material characteristics over a depth profile. Cast free films of organic- or aqueous-based, non-chromated aerospace primers, when cured for about one week, had very different water vapour transport (through-plane) behaviour. In addition, both types of primer films showed strong anisotropic behaviour in in-plane versus through-plane water vapour transport rates. We report the differences between the organic- and aqueous-based aircraft primer films samples and their surface depth profiles. In bulk PALS measurements, an aged, organic-based film exhibited typical lifetimes and intensities for a particulate-containing polymer film on both faces. In contrast, aqueous-based films exhibited face oriented-dependent differences. In all aqueous- based samples, the I3 value of the back of the sample was smaller. The primer film samples were also evaluated with mono-energetic positron beam techniques to generate depth profile information. The heterogeneity in the samples was verified by Doppler broadening of energy spectroscopy (DBES). A model for the differences in the faces of the films, and their layered structure is discussed.

  13. New redox mediator-modified polysulfone composite films for the development of dehydrogenase-based biosensors.

    PubMed

    Prieto-Simón, Beatriz; Fàbregas, Esteve

    2006-07-15

    This work presents polysulfone membranes as new materials for the development of compact dehydrogenase-based biosensors. Composite films were prepared by mixing polysulfone with graphite and were deposited on epoxy-graphite composite electrodes. Redox mediators were successfully immobilized in the composite film leading to highly reproducible biosensors, without leakage of the immobilized species. This results in a more reliable analytical system as, at the same time, problems of electrode fouling related to the detection of the coenzyme nicotinamide adenine dinucleotide (NADH) on which is based the amperometric detection of dehydrogenase-based biosensors are avoided. Scanning electron microscopy was used to study the morphological characteristics of the surface and the cross-section of the polysulfone-graphite composite films. Several procedures to immobilize enzymes in these membranes were demonstrated. Glutamate dehydrogenase (GlDH) was immobilized as an example of dehydrogenase enzyme, in this case for the development of an ammonium biosensor. High sensitivity, good selectivity, wide linear ranges and short response times were obtained for the optimized sensors and biosensors. Their good performance combined with the simplicity of the construction method, make the polysulfone-graphite composite films attractive matrices for the development of new enzyme-based biosensors, especially those based on dehydrogenase enzymes. PMID:16448813

  14. Development and Characterization of Novel Films Based on Sulfonamide-Chitosan Derivatives for Potential Wound Dressing

    PubMed Central

    Dragostin, Oana Maria; Samal, Sangram Keshari; Lupascu, Florentina; Pânzariu, Andreea; Dubruel, Peter; Lupascu, Dan; Tuchilus, Cristina; Vasile, Cornelia; Profire, Lenuta

    2015-01-01

    The objective of this study was to develop new films based on chitosan functionalized with sulfonamide drugs (sulfametoxydiazine, sulfadiazine, sulfadimetho-xine, sulfamethoxazol, sulfamerazine, sulfizoxazol) in order to enhance the biological effects of chitosan. The morphology and physical properties of functionalized chitosan films as well the antioxidant effects of sulfonamide-chitosan derivatives were investigated. The chitosan-derivative films showed a rough surface and hydrophilic properties, which are very important features for their use as a wound dressing. The film based on chitosan-sulfisoxazol (CS-S6) showed the highest swelling ratio (197%) and the highest biodegradation rate (63.04%) in comparison to chitosan film for which the swelling ratio was 190% and biodegradation rate was only 10%. Referring to the antioxidant effects the most active was chitosan-sulfamerazine (CS-S5) which was 8.3 times more active than chitosan related to DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging ability. This compound showed also a good ferric reducing power and improved total antioxidant capacity. PMID:26694354

  15. Enhancements in Magnesium Die Casting Impact Properties

    SciTech Connect

    David Schwam; John F. Wallace; Yulong Zhu; Srinath Viswanathan; Shafik Iskander

    2000-06-30

    The need to produce lighter components in transportation equipment is the main driver in the increasing demand for magnesium castings. In many automotive applications, components can be made of magnesium or aluminum. While being lighter, often times the magnesium parts have lower impact and fatigue properties than the aluminum. The main objective of this study was to identify potential improvements in the impact resistance of magnesium alloys. The most common magnesium alloys in automotive applications are AZ91D, AM50 and AM60. Accordingly, these alloys were selected as the main candidates for the study. Experimental quantities of these alloys were melted in an electrical furnace under a protective atmosphere comprising sulfur hexafluoride, carbon dioxide and dry air. The alloys were cast both in a permanent mold and in a UBE 315 Ton squeeze caster. Extensive evaluation of tensile, impact and fatigue properties was conducted at CWRU on permanent mold and squeeze cast test bars of AZ91, AM60 and AM50. Ultimate tensile strength values between 20ksi and 30ksi were obtained. The respective elongations varied between 25 and 115. the Charpy V-notch impact strength varied between 1.6 ft-lb and 5 ft-lb depending on the alloy and processing conditions. Preliminary bending fatigue evaluation indicates a fatigue limit of 11-12 ksi for AM50 and AM60. This is about 0.4 of the UTS, typical for these alloys. The microstructures of the cast specimens were investigated with optical and scanning electron microscopy. Concomitantly, a study of the fracture toughness in AM60 was conducted at ORNL as part of the study. The results are in line with values published in the literature and are representative of current state of the art in casting magnesium alloys. The experimental results confirm the strong relationship between aluminum content of the alloys and the mechanical properties, in particular the impact strength and the elongation. As the aluminum content increases from about 5% in AM50 to over 9% in AZ91, more of the intermetallic Mg17Al12 is formed in the microstructure. For instance, for 15 increase in the aluminum content from AM50 to AM60, the volume fraction of eutectic present in the microstructure increases by 35%! Eventually, the brittle Mg17Al12 compound forms an interconnected network that reduces ductility and impact resistance. The lower aluminum in AM50 and AM60 are therefore a desirable feature in applications that call for higher impact resistance. Further improvement in impact resistance depends on the processing condition of the casting. Sound castings without porosity and impurities will have better mechanical properties. Since magnesium oxidizes readily, good melting and metal transfer practices are essential. The liquid metal has to be protected from oxidation at all times and entrainment of oxide films in the casting needs to be prevented. In this regard, there is evidence that us of vacuum to evacuate air from the die casting cavity can improve the quality of the castings. Fast cooling rates, leading to smaller grain size are beneficial and promote superior mechanical properties. Micro-segregation and banding are two additional defect types often encountered in magnesium alloys, in particular in AZ91D. While difficult to eliminate, segregation can be minimized by careful thermal management of the dies and the shot sleeve. A major source of segregation is the premature solidification in the shot sleeve. The primary solid dendrites are carried into the casting and form a heterogeneous structure. Furthermore, during the shot, segregation banding can occur. The remedies for this kind of defects include a hotter shot sleeve, use of insulating coatings on the shot sleeve and a short lag time between pouring into the shot sleeve and the shot.

  16. Fracture Mechanism and Toughness Optimization of Macroscopic Thick Graphene Oxide Film

    PubMed Central

    Ye, Shibing; Chen, Bin; Feng, Jiachun

    2015-01-01

    Combined high strength and toughness of film materials are rather important for their industrial applications. As a new class of films, graphene oxide films (GOFs) attract intense attention in many applications but are frequently divergent, inconsistent, and poorly reproducible in their mechanical properties. In this study, we first demonstrate that different chemical compositions and assembly structures probably are responsible for the difference in elongations between cast GOFs and filtration GOFs. Comprehensive analysis of the morphologies and mechanical properties indicates that the enhanced elongation of the thick cast GOFs is mainly attributed to the presence of a unique skin-wrinkles-skin structure, which more easily forms in cast GOFs than in filtration counterparts. On the basis of this finding, we attempt to optimize the strength-toughness performance of the cast GOFs by adjusting their structures. With an appropriate thickness of 12.5??m, the GOFs can achieve an ultrahigh toughness up to 4.37?MJ m?3, which is even comparable to the polymer-toughening graphene/GO-based paper-like materials. Such an optimization of the mechanical properties from the perspective of skin-wrinkles-skin structure appears to be a universal approach that could be extended to a variety of other film materials. PMID:26310835

  17. Effect of chromium and phosphorus on the physical properties of iron and titanium-based amorphous metallic alloy films

    NASA Technical Reports Server (NTRS)

    Distefano, S.; Rameshan, R.; Fitzgerald, D. J.

    1991-01-01

    Amorphous iron and titanium-based alloys containing various amounts of chromium, phosphorus, and boron exhibit high corrosion resistance. Some physical properties of Fe and Ti-based metallic alloy films deposited on a glass substrate by a dc-magnetron sputtering technique are reported. The films were characterized using differential scanning calorimetry, stress analysis, SEM, XRD, SIMS, electron microprobe, and potentiodynamic polarization techniques.

  18. Extrusion cast explosive

    DOEpatents

    Scribner, Kenneth J. (Livermore, CA)

    1985-01-01

    Improved, multiphase, high performance, high energy, extrusion cast explosive compositions, comprising, a crystalline explosive material; an energetic liquid plasticizer; a urethane prepolymer, comprising a blend of polyvinyl formal, and polycaprolactone; a polyfunctional isocyanate; and a catalyst are disclosed. These new explosive compositions exhibit higher explosive content, a smooth detonation front, excellent stability over long periods of storage, and lower sensitivity to mechanical stimulants.

  19. Hair Casts or Pseudonits

    PubMed Central

    França, Katlein; Villa, Ricardo Tadeu; Silva, Isabella Rezende; de Carvalho, Cristine Almeida; Bedin, Valcinir

    2011-01-01

    Hair casts or pseudonits are thin, elongated, cylindrical concretions that encircle the hair shaft and can be easily dislodged. A case of pseudonits in a 9-year-old girl is reported. Though not unusual, false diagnoses are common. PMID:22223977

  20. Charge carrier trapping in highly-ordered lyotropic chromonic liquid crystal films based on ionic perylene diimide derivatives

    NASA Astrophysics Data System (ADS)

    Soroka, Pavlo V.; Vakhnin, Alexander Yu.; Skryshevskiy, Yuriy A.; Boiko, Oleksandr P.; Anisimov, Maksim I.; Slominskiy, Yuriy L.; Nazarenko, Vassili G.; Genoe, Jan; Kadashchuk, Andrey

    2014-12-01

    Charge carrier trapping in thin films of lyotropic chromonic liquid crystals (LCLCs) based on ionic perylene diimide derivative and in chemically-similar neutral N,N'-dipentyl-3,4,9,10-perylene-dicarboximide (PTCDI-C5) films is investigated by thermally-stimulated luminescence (TSL) technique. The LCLC films comprise elongated molecular aggregates featuring a long-range orientational order. The obtained results provide direct evidence for the improved energetic ordering (smaller effective energetic disorder) in aggregated LCLC films as compared to conventional PTCDI-C5 films. The width of the density-of-state distribution of 0.09 eV and 0.13 eV was estimated for the LCLC and PTCDI-C5 films, respectively. Relatively small effective energetic disorder in LCLC films is ascribed to formation of macroscopically larger LCLC aggregates.

  1. Swift heavy ion induced surface modification for tailoring coercivity in Fe-Ni based amorphous thin films

    SciTech Connect

    Thomas, Senoy; Thomas, Hysen; Anantharaman, M. R.; Avasthi, D. K.; Tripathi, A.; Ramanujan, R. V.

    2009-02-01

    Fe-Ni based amorphous thin films were prepared by thermal evaporation. These films were irradiated by 108 MeV Ag{sup 8+} ions at room temperature with fluences ranging from 1x10{sup 12} to 3x10{sup 13} ions/cm{sup 2} using a 15 UD Pelletron accelerator. Glancing angle x-ray diffraction studies showed that the irradiated films retain their amorphous nature. The topographical evolution of the films under swift heavy ion (SHI) bombardment was probed using atomic force microscope and it was noticed that surface roughening was taking place with ion beam irradiation. Magnetic measurements using a vibrating sample magnetometer showed that the coercivity of the films increases with an increase in the ion fluence. The observed coercivity changes are correlated with topographical evolution of the films under SHI irradiation. The ability to modify the magnetic properties via SHI irradiation could be utilized for applications in thin film magnetism.

  2. The Effect of Temperature and Rotational Speed on Structure and Mechanical Properties of Cast Cu Base Alloy (Cu-Al-Si-Fe) Welded by Semisolid Stir Joining Method

    NASA Astrophysics Data System (ADS)

    Ferasat, Keyvan; Aashuri, Hossein; Kokabi, Amir Hossein; Shafizadeh, Mahdi; Nikzad, Siamak

    2015-09-01

    Semisolid stir joining has been under deliberation as a possible method for joining of copper alloys. In this study, the effect of temperature and rotational speed of stirrer on macrostructure evaluation and mechanical properties of samples were investigated. Optical microscopy and X-ray diffraction were performed for macro and microstructural analysis. A uniform micro-hardness profile was attained by semisolid stir joining method. The ultimate shear strength and bending strength of welded samples were improved in comparison with the cast sample. There is also lower area porosity in welded samples than the cast metal. The mechanical properties were improved by increasing temperature and rotational speed of the joining process.

  3. The Effect of Temperature and Rotational Speed on Structure and Mechanical Properties of Cast Cu Base Alloy (Cu-Al-Si-Fe) Welded by Semisolid Stir Joining Method

    NASA Astrophysics Data System (ADS)

    Ferasat, Keyvan; Aashuri, Hossein; Kokabi, Amir Hossein; Shafizadeh, Mahdi; Nikzad, Siamak

    2015-12-01

    Semisolid stir joining has been under deliberation as a possible method for joining of copper alloys. In this study, the effect of temperature and rotational speed of stirrer on macrostructure evaluation and mechanical properties of samples were investigated. Optical microscopy and X-ray diffraction were performed for macro and microstructural analysis. A uniform micro-hardness profile was attained by semisolid stir joining method. The ultimate shear strength and bending strength of welded samples were improved in comparison with the cast sample. There is also lower area porosity in welded samples than the cast metal. The mechanical properties were improved by increasing temperature and rotational speed of the joining process.

  4. Effects of nanoclay type on the physical and antimicrobial properties of PVOH-based nanocomposite films

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Polyvinyl alcohols-based nanocomposite films were fabricated with four types of montmorillonite (MMT) nanoclay, including 18-amino stearic acid (I.24TL), methyl, bis hydroxyethyl, octadecyl ammonium (I.34TCN), di-methyl, di-hydrogenated tallow ammonium/siloxane (I.44PSS) organically modified MMT, an...

  5. Activated Charcoal Based Diffusive Gradients in Thin Films for in Situ Monitoring of Bisphenols in Waters

    E-print Network

    Ma, Lena

    Activated Charcoal Based Diffusive Gradients in Thin Films for in Situ Monitoring of Bisphenols, Gainesville, Florida 32611, United States *S Supporting Information ABSTRACT: Widespread use of bisphenols monitoring of BPs in waters. Endocrine-disrupting chemicals, including bisphenols (BPs), are widely used

  6. Enhanced frequency response of a highly transparent PVDF-graphene based thin film acoustic actuator.

    PubMed

    Lee, James S; Shin, Keun-Young; Kim, Chanhoi; Jang, Jyongsik

    2013-12-01

    A high-performance polyvinylidene fluoride (PVDF) based thin film acoustic actuator with chemical vapor deposition (CVD) graphene electrodes was successfully fabricated. Importantly, it showed 60, 19, and 22% enhancement in the bass, middle and treble frequency response, respectively. PMID:24136447

  7. Tradition and Change in Modern Morocco, An Instructional Unit Based on Film Study.

    ERIC Educational Resources Information Center

    Murphy, E. Jefferson

    The learning unit for grade levels 8, 9, or 10 is based upon viewing and discussing the film "Morocco: Chaoui Faces His Future." Among the learning objectives of the unit are the following: (1) to expand inquiry skills and the ability to formulate concepts, generalizations, and hypotheses; (2) to introduce the student to the interplay of forces of…

  8. Surface Plasmon Sensor Based on the Enhanced Light Transmission through Arrays of Nanoholes in Gold Films

    E-print Network

    Brolo, Alexandre G.

    Surface Plasmon Sensor Based on the Enhanced Light Transmission through Arrays of Nanoholes in Gold of nanoholes in a gold film were used to monitor the binding of organic and biological molecules upon the resonant surface plasmon enhanced transmission through the array of nanoholes. The sensitivity

  9. Low-loss plasmonic metamaterial based on epitaxial gold monocrystal film

    E-print Network

    Zheludev, Nikolay

    Low-loss plasmonic metamaterial based on epitaxial gold monocrystal film V. A. Fedotov,1,2,* T Centre for Photonic Metamaterials, University of Southampton, SO17 1BJ, UK 3 School of Electronics high-finesse plasmonic metamaterial with strong resonant response in the near-IR spectral range

  10. Flexible and transparent supercapacitor based on In2O3 nanowire/carbon nanotube heterogeneous films

    E-print Network

    Zhou, Chongwu

    Flexible and transparent supercapacitor based on In2O3 nanowire/carbon nanotube heterogeneous films; accepted 17 December 2008; published online 28 January 2009 In this paper, a supercapacitor galvanostatic measurements. In addition, to study the stability of flexible and transparent supercapacitor

  11. Composite edible films based on hydroxypropyl methyl cellulose reinforced with microcrystalline cellulose nanoparticles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It has been stated that hydroxypropyl methyl cellulose (HPMC) based films have promising applications in the food industry because of their environmental appeal, low cost, flexibility and transparency. Nevertheless, their mechanical and moisture barrier properties should be improved. The aim of th...

  12. Nonlinear Model-Based Control of Thin-Film Drying for Continuous Pharmaceutical Manufacturing

    E-print Network

    flexibility, reliability, and efficiency of the production process.3,4 In addition, continuous manufacturingNonlinear Model-Based Control of Thin-Film Drying for Continuous Pharmaceutical Manufacturing Ali process used in the continuous manufacturing of pharmaceutical tablets. In this nonlinear distributed

  13. Inverted nanocone-based thin film photovoltaics with omnidirectionally enhanced performance.

    PubMed

    Lin, Qingfeng; Leung, Siu-Fung; Lu, Linfeng; Chen, Xiaoyuan; Chen, Zhuo; Tang, Haoning; Su, Wenjun; Li, Dongdong; Fan, Zhiyong

    2014-06-24

    Thin film photovoltaic (PV) technologies are highly attractive for low-cost solar energy conversion and possess a wide range of potential applications from building-integrated PV generation to portable power sources. Inverted nanocones (i-cones) have been demonstrated as a promising structure for practical thin film PV devices/modules, owning to their antireflection effect, self-cleaning function, superior mechanical robustness, and so forth. In this work, we have demonstrated a low-cost and scalable approach to achieve perfectly ordered i-cone arrays. Thereafter, thin film amorphous silicon (a-Si:H) solar cells have been fabricated based on various i-cone substrates with different aspect ratios and pitches to investigate the impact of geometry of i-cone nanostructures on the performance of the as-obtained PV devices. Intriguingly, the optical property investigations and device performance characterizations demonstrated that the 0.5-aspect-ratio i-cone-based device performed the best on both light absorption capability and energy conversion efficiency, which is 34% higher than that of the flat counterpart. Moreover, the i-cone-based device enhanced the light absorption and device performance over the flat reference device omnidirectionally. These results demonstrate a viable and convenient route toward scalable fabrication of nanostructures for high-performance thin film PV devices based on a broad range of materials. PMID:24873372

  14. SICS. A Sensor-Based In-Line Control System for the Surfaces of Continuously Cast Slabs

    SciTech Connect

    Chang, Tzyy-Shuh

    2013-09-23

    The Phase II project has been carried out in accordance to the proposed tasks and budget, based on the original and extended schedule. The R&D team designed and implemented the test unit for the full width coverage, installed the unit in a caster. The development work further included enhanced image processing, in-depth defect study and process control models. The function, operation, and maintenance of the SICS was thoroughly studied during the Phase II research. The experience indicates additional hardware and procedures are required to make the SICS a commercially ready product in operation and maintenance aspect. Such developments have been finished and the team is contacting potential customers for the first commercial installation of SICS. Additionally, OGT is exploring the possibility to team up with a US company that specializes in surface cleaning for slabs/blooms/billets such that the in-line surface inspection can be integrated with in-line surface clean up for the maximum benefit to the steel industry.

  15. Enhanced antimicrobial activity of starch-based film impregnated with thermally processed tannic acid, a strong antioxidant.

    PubMed

    Pyla, Rajkumar; Kim, Tae-Jo; Silva, Juan L; Jung, Yean-Sung

    2010-02-28

    Starch-based films impregnated with fresh tannic acid (FTA/starch film) and thermally processed tannic acid (PTA/starch film) were assessed for inhibition of Escherichia coli O157:H7 and Listeria monocytogenes. Disc-diffusion assay revealed that the PTA/starch film showed larger clear zone around the film on the bacterial lawn than the FTA/starch film at the same tannic acid concentrations (0.45 to 4.5mg per disc). Viable cell count assays in tryptic soy broth showed that the PTA/starch film also had a stronger antimicrobial activity on these foodborne pathogens than the FTA/starch film. L. monocytogenes did not replicate in trypic soy broth containing the FTA/starch film for the first 8h but multiplied up to 9.22 log CFU/ml at 48 h of incubation. The PTA/starch film caused a 2.72-log decrease in L. monocytogenes cells over the same time period. While 5-log E. coli O157:H7 cells were inactivated by the FTA/starch film within 48 h, more than 7-log E. coli O157:H7 cells were killed by the PTA/starch film over the same period. The antimicrobial activity of FTA/starch and PTA/starch film was primarily pH independent. HPLC measurement of the FTA or PTA release from starch film in water revealed that their release kinetic curves were in well match with their inactivation curves for E. coli O157:H7 and L. monocytogenes in 0.1% peptone water. In addition to antimicrobial activity, FTA showed antioxidant activity on soybean oil by doubling the induction time of oil oxidation. PTA further enhanced the oxidative stability of the oil by 17%. These results suggested that the use of processed tannic acid in starch films could improve the safety and quality of foods. PMID:20051308

  16. SU-E-CAMPUS-T-06: Radiochromic Film Analysis Based On Principal Components

    SciTech Connect

    Wendt, R

    2014-06-15

    Purpose: An algorithm to convert the color image of scanned EBT2 radiochromic film [Ashland, Covington KY] into a dose map was developed based upon a principal component analysis. The sensitive layer of the EBT2 film is colored so that the background streaks arising from variations in thickness and scanning imperfections may be distinguished by color from the dose in the exposed film. Methods: Doses of 0, 0.94, 1.9, 3.8, 7.8, 16, 32 and 64 Gy were delivered to radiochromic films by contact with a calibrated Sr-90/Y-90 source. They were digitized by a transparency scanner. Optical density images were calculated and analyzed by the method of principal components. The eigenimages of the 0.94 Gy film contained predominantly noise, predominantly background streaking, and background streaking plus the source, respectively, in order from the smallest to the largest eigenvalue. Weighting the second and third eigenimages by ?0.574 and 0.819 respectively and summing them plus the constant 0.012 yielded a processed optical density image with negligible background streaking. This same weighted sum was transformed to the red, green and blue space of the scanned images and applied to all of the doses. The curve of processed density in the middle of the source versus applied dose was fit by a twophase association curve. A film was sandwiched between two polystyrene blocks and exposed edge-on to a different Y-90 source. This measurement was modeled with the GATE simulation toolkit [Version 6.2, OpenGATE Collaboration], and the on-axis depth-dose curves were compared. Results: The transformation defined using the principal component analysis of the 0.94 Gy film minimized streaking in the backgrounds of all of the films. The depth-dose curves from the film measurement and simulation are indistinguishable. Conclusion: This algorithm accurately converts EBT2 film images to dose images while reducing noise and minimizing background streaking. Supported by a sponsored research agreement from IsoTherapeutics Group, LLC.

  17. Modeling microstructure development in gray cast irons

    NASA Astrophysics Data System (ADS)

    Goettsch, David D.; Dantzig, Jonathan A.

    1994-05-01

    Recent years have seen increasing use of solidification process modeling as a tool to aid in the analysis and elimination of manufacturing defects in castings. Grain size and other microstructural features such as second-phase morphology and distribution are the primary factors in determining the mechanical properties in cast metals. In this work, a representation of nucleation and growth kinetics for gray cast irons, based on a statistical description of the microstructure, has been coupled with a commercial finite-element method code for transient heat-flow calculation to determine microstructure. Features predicted include eutectic cell size, fractions of gray and white iron, graphite morphology, percent pearlite, percent ferrite, and pearlite spacing. The predicted microstructure can then be used to determine the strength and fatigue properties using published correlations. The theoretical development and results of the finite-elementbased model will be discussed and compared with experimental results.

  18. Spray casting project final report

    SciTech Connect

    Churnetski, S.R.; Thompson, J.E.

    1996-08-01

    Lockheed Martin Energy Systems, Inc. (Energy Systems), along with other participating organizations, has been exploring the feasibility of spray casting depleted uranium (DU) to near-net shape as a waste minimization effort. Although this technology would be useful in a variety of applications where DU was the material of choice, this effort was aimed primarily at gamma-shielding components for use in storage and transportation canisters for high-level radioactive waste, particularly in the Multipurpose Canister (MPC) application. In addition to the waste-minimization benefits, spray casting would simplify the manufacturing process by allowing the shielding components for MPC to be produced as a single component, as opposed to multiple components with many fabrication and assembly steps. In earlier experiments, surrogate materials were used to simulate the properties (specifically reactivity and density) of DU. Based on the positive results from those studies, the project participants decided that further evaluation of the issues and concerns that would accompany spraying DU was warranted. That evaluation occupied substantially all of Fiscal Year 1995, yielding conceptual designs for both an intermediate facility and a production facility and their associated engineering estimates. An intermediate facility was included in this study to allow further technology development in spraying DU. Although spraying DU to near-net shape seems to be feasible, a number of technical, engineering, and safety issues would need to be evaluated before proceeding with a production facility. This report is intended to document the results from the spray-casting project and to provide information needed by anyone interested in proceeding to the next step.

  19. Fission-fragment detector for DANCE based on thin scintillating films

    NASA Astrophysics Data System (ADS)

    Rusev, G.; Roman, A. R.; Daum, J. K.; Springs, R. K.; Bond, E. M.; Jandel, M.; Baramsai, B.; Bredeweg, T. A.; Couture, A.; Favalli, A.; Ianakiev, K. D.; Iliev, M. L.; Mosby, S.; Ullmann, J. L.; Walker, C. L.

    2015-12-01

    A fission-fragment detector based on thin scintillating films has been built to serve as a trigger/veto detector in neutron-induced fission measurements at DANCE. The fissile material is surrounded by scintillating films providing 4 ? detection of the fission fragments. The scintillation photons were registered with silicon photomultipliers. A measurement of the 235U (n, f) reaction with this detector at DANCE revealed a correct time-of-flight spectrum and provided an estimate for the efficiency of the prototype detector of 11.6(7)%. Design and test measurements with the detector are described.

  20. Across-plane thermal characterization of films based on amplitude-frequency profile in photothermal technique

    SciTech Connect

    Xu, Shen; Wang, Xinwei

    2014-10-15

    This work develops an amplitude method for the photothermal (PT) technique to analyze the amplitude of the thermal radiation signal from the surface of a multilayered film sample. The thermal conductivity of any individual layer in the sample can be thereby determined. Chemical vapor deposited SiC film samples (sample 1 to 3: 2.5 to 3.5 ?m thickness) with different ratios of Si to C and thermally oxidized SiO{sub 2} film (500 nm thickness) on silicon substrates are studied using the amplitude method. The determined thermal conductivity based on the amplitude method is 3.58, 3.59, and 2.59 W/m?K for sample 1 to 3 with ±10% uncertainty. These results are verified by the phase shift method, and sound agreement is obtained. The measured thermal conductivity (k) of SiC is much lower than the value of bulk SiC. The large k reduction is caused by the structure difference revealed by Raman spectroscopy. For the SiO{sub 2} film, the thermal conductivity is measured to be 1.68 ± 0.17 W/m?K, a little higher than that obtained by the phase shift method: 1.31 ± 0.06 W/m?K. Sensitivity analysis of thermal conductivity and interfacial resistance is conducted for the amplitude method. Its weak-sensitivity to the thermal contact resistance, enables the amplitude method to determine the thermal conductivity of a film sample with little effect from the interface thermal resistance between the film and substrate. The normalized amplitude ratio at a high frequency to that at a low frequency provides a reliable way to evaluate the effusivity ratio of the film to that of the substrate.

  1. High Temperature - Thin Film Strain Gages Based on Alloys of Indium Tin Oxide

    NASA Technical Reports Server (NTRS)

    Gregory, Otto J.; Cooke, James D.; Bienkiewicz, Joseph M.

    1998-01-01

    A stable, high temperature strain gage based on reactively sputtered indium tin oxide (ITO) was demonstrated at temperatures up to 1050 C. These strain sensors exhibited relatively large, negative gage factors at room temperature and their piezoresistive response was both linear and reproducible when strained up to 700 micro-in/in. When cycled between compression and tension, these sensors also showed very little hysteresis, indicating excellent mechanical stability. Thin film strain gages based on selected ITO alloys withstood more than 50,000 strain cycles of +/- 500 micro-in/in during 180 hours of testing in air at 1000 C, with minimal drift at temperature. Drift rates as low as 0.0009%/hr at 1000 C were observed for ITO films that were annealed in nitrogen at 700 C prior to strain testing. These results compare favorably with state of the art 10 micro-m thick PdCr films deposited by NASA, where drift rates of 0.047%/hr at 1050 C were observed. Nitrogen annealing not only produced the lowest drift rates to date, but also produce the largest dynamic gage factors (G = 23.5). These wide bandgap, semiconductor strain sensors also exhibited moderately low temperature coefficients of resistance (TCR) at temperatures up to 1100 C, when tested in a nitrogen ambient. A TCR of +230 ppm/C over the temperature range 200 C < T < 500 C and a TCR of -469 ppm/C over the temperature range 600 C < T < 1100 C was observed for the films tested in nitrogen. However, the resistivity behavior changed considerably when the same films were tested in oxygen ambients. A TCR of -1560 ppm/C was obtained over the temperature range of 200 C < T < 1100 C. When similar films were protected with an overcoat or when ITO films were prepared with higher oxygen contents in the plasma, two distinct TCR's were observed. At T < 800 C, a linear TCR of -210 ppm/C was observed and at T > 800 C, a linear TCR of -2170 DDm/C was observed. The combination of a moderately low TCR and a relatively large gage factor make these semiconducting oxide films promising candidates for the active strain elements in high temperature thin film strain gages, particularly in applications where static strain measurement is desired.

  2. An Update on ToxCast

    EPA Science Inventory

    In its first phase, ToxCast™ is profiling over 300 well-characterized chemicals (primarily pesticides) in over 400 HTS endpoints. These endpoints include biochemical assays of protein function, cell-based transcriptional reporter assays, multi-cell interaction assays, transcripto...

  3. K-Band Reflectarray Antenna Based on Ferroelectric Thin Films: What Have We Learned so Far

    NASA Technical Reports Server (NTRS)

    Miranda, Felix A.; Romanofsky, Robert; Mueller, Carl H.; VanKeuls, Fred

    2002-01-01

    The Applied RF Technology Branch of the NASA Glenn Research Center, Cleveland, Ohio, has an on-going effort in the area of thin film ferroelectric technology for microwave applications. Particular attention has been given to developing ferroelectric phase shifters for the implementation and experimental demonstration of an electronically steerable reflectarray antenna. In the process of optimizing these material to fit the implementation requirements of the aforementioned antenna, we have accumulated a great deal of information and knowledge in areas such as the effect of the composition of the ferroelectric thin films on phase shifter performance, self assembled monolayers (SAMs) in the metallic/ferroelectric interface and their impact on phase shifter performance, correlation between microstructure and microwave properties, and the effect of selective etching on the overall performance of a thin film-ferroelectric based microwave component, amongst others. We will discuss these issues and will provide an up-dade of the current development status of the reflect-array antenna.

  4. Impermeable barrier films and protective coatings based on reduced graphene oxide

    NASA Astrophysics Data System (ADS)

    Su, Y.; Kravets, V. G.; Wong, S. L.; Waters, J.; Geim, A. K.; Nair, R. R.

    2014-09-01

    Flexible barrier films preventing permeation of gases and moistures are important for many industries ranging from food to medical and from chemical to electronic. From this perspective, graphene has recently attracted particular interest because its defect-free monolayers are impermeable to all atoms and molecules. However, it has been proved to be challenging to develop large-area defectless graphene films suitable for industrial use. Here we report barrier properties of multilayer graphitic films made by gentle chemical reduction of graphene oxide laminates with hydroiodic and ascorbic acids. They are found to be highly impermeable to all gases, liquids and aggressive chemicals including, for example, hydrofluoric acid. The exceptional barrier properties are attributed to a high degree of graphitization of the laminates and little structural damage during reduction. This work indicates a close prospect of graphene-based flexible and inert barriers and protective coatings, which can be of interest for numerous applications.

  5. Third generation biosensing matrix based on Fe-implanted ZnO thin film

    SciTech Connect

    Saha, Shibu; Gupta, Vinay; Sreenivas, K.; Tan, H. H.; Jagadish, C.

    2010-09-27

    Third generation biosensor based on Fe-implanted ZnO (Fe-ZnO) thin film has been demonstrated. Implantation of Fe in rf-sputtered ZnO thin film introduces redox center along with shallow donor level and thereby enhance its electron transfer property. Glucose oxidase (GOx), chosen as model enzyme, has been immobilized on the surface of the matrix. Cyclic voltammetry and photometric assay show that the prepared bioelectrode, GOx/Fe-ZnO/ITO/Glass is sensitive to the glucose concentration with enhanced response of 0.326 {mu}A mM{sup -1} cm{sup -2} and low Km of 2.76 mM. The results show promising application of Fe-implanted ZnO thin film as an attractive matrix for third generation biosensing.

  6. Self-referenced biosensor based on thin dielectric grating combined with thin metal film.

    PubMed

    Abutoama, Mohammad; Abdulhalim, Ibrahim

    2015-11-01

    Surface plasmon resonance biosensors based on grating coupling exhibiting two plasmons are less known because usually thick gratings and thick metal films are used. In this paper we show that when thin dielectric grating is used on top of thin metal film two surface plasmons are generated at the two boundaries of the metal film represented as two dips in the reflectivity or peaks in the absorption. One of the plasmons is sensitive to the analyte refractive index (sensitivity 580nm/RIU) while the other is sensitive to the refractive index of the substrate; hence it can be used as a reference. This self-reference makes the measurement more accurate and less sensitive to temperature fluctuations and optomechanical drifts. Field distribution calculations show that the plasmon excited at the metal-substrate interface is a long range plasmon with large penetration depth. PMID:26561135

  7. Semiconducting properties of amorphous GaZnSnO thin film based on combinatorial electronic structures

    SciTech Connect

    Kim, B. K.; Park, J. S.; Kim, D. H.; Chung, K. B.

    2014-05-05

    Semiconducting properties and electronic structures of amorphous GaZnSnO (GZTO) thin films are investigated with respect to metal cationic composition. An increase of the cationic Sn ratio resulted in an increase of the carrier concentration and a decrease of the mobility of the films. Combinatorial analysis revealed that the electrical characteristics of GZTO films are strongly correlated to changes in electronic structure. The increase in carrier concentration is related to the generation of vacancies by the changes of oxygen coordination around the cationic metal and the shallow band edge state below the conduction band. On the other hand, the decrease of mobility can be explained by the deep band edge state, and the difference between the experimental conduction band and simulated conduction band by the combinatorial electronic structure based on the chemical composition.

  8. Impermeable barrier films and protective coatings based on reduced graphene oxide.

    PubMed

    Su, Y; Kravets, V G; Wong, S L; Waters, J; Geim, A K; Nair, R R

    2014-01-01

    Flexible barrier films preventing permeation of gases and moistures are important for many industries ranging from food to medical and from chemical to electronic. From this perspective, graphene has recently attracted particular interest because its defect-free monolayers are impermeable to all atoms and molecules. However, it has been proved to be challenging to develop large-area defectless graphene films suitable for industrial use. Here we report barrier properties of multilayer graphitic films made by gentle chemical reduction of graphene oxide laminates with hydroiodic and ascorbic acids. They are found to be highly impermeable to all gases, liquids and aggressive chemicals including, for example, hydrofluoric acid. The exceptional barrier properties are attributed to a high degree of graphitization of the laminates and little structural damage during reduction. This work indicates a close prospect of graphene-based flexible and inert barriers and protective coatings, which can be of interest for numerous applications. PMID:25208890

  9. Bionanocomposite films based on plasticized PLA-PHB/cellulose nanocrystal blends.

    PubMed

    Arrieta, M P; Fortunati, E; Dominici, F; López, J; Kenny, J M

    2015-05-01

    Optically transparent plasticized poly(lactic acid) (PLA) based bionanocomposite films intended for food packaging were prepared by melt blending. Materials were plasticized with 15wt% of acetyl(tributyl citrate) (ATBC) to improve the material processability and to obtain flexibile films. Poly(hydroxybutyrate) (PHB) was used to increase PLA crystallinity. The thermal stability of the PLA-PHB blends was improved by the addition of 5 wt% of cellulose nanocrystals (CNC) or modified cellulose nanocrystals (CNCs) synthesized from microcrystalline cellulose. The combination of ATBC and cellulose nanocrystals, mainly the better dispersed CNCs, improved the interaction between PLA and PHB. Thus, an improvement on the oxygen barrier and stretchability was achieved in PLA-PHB-CNCs-ATBC which also displayed somewhat UV light blocking effect. All bionanocomposite films presented appropriate disintegration in compost suggesting their possible applications as biodegradable packaging materials. PMID:25659698

  10. Blue surface-emitting distributed feedback lasers based on TPD-doped films.

    PubMed

    Calzado, Eva M; Villalvilla, Jose M; Boj, Pedro G; Quintana, Jose A; Postigo, Pablo A; Díaz-García, María A

    2010-01-20

    Single-mode second-order distributed feedback (DFB) lasers with low threshold, based on polystyrene films doped with 30 wt. % of the hole-transporting organic molecule N,N'-bis (3-methylphenyl)-N,N'-diphenylbenzidine (TPD) are reported. The laser emission wavelength was tuned between 415 and 427 nm by film thickness variation. The effectiveness of the DFB grating in improving the laser performance is evidenced by the observation of linewidths and laser thresholds lower than those of the amplified spontaneous emission characteristics shown by films without gratings. The use of holographic lithography as the technique for grating recording has allowed us to prepare large samples in a fast, versatile, and simple manner. PMID:20090812

  11. Base and acid treatment of SWCNT-RNA transparent conductive films.

    PubMed

    Wang, Ranran; Sun, Jing; Gao, Lian; Zhang, Jing

    2010-08-24

    RNA was used to exfoliate single-walled carbon nanotubes (SWCNTs) in aqueous solution, and the ratio of it was optimized to obtain the best dispersion state. The obtained homogeneous SWCNT solution with small bundle size was used to prepare flexible transparent conductive films by filtration method. Sodium hydroxide treatment combining short-time acid treatment was used to remove the RNA molecules. After treatment, the sheet resistance of the films decreased significantly, while the change on the transmittance was negligible. Besides, the polyethylene terephthalate substrate would not turn brittle through this treatment process. Flexible films with outstanding performance (190 Omega/sq, 85%) and good stability were obtained after treatment. X-ray photoelectron spectroscopy and scanning electron microscope were used to analyze the role of base and acid treatment in detail. PMID:20731462

  12. Morphological analysis of co-evaporated blend films based on initial growth for organic photovoltaics

    NASA Astrophysics Data System (ADS)

    Shibata, Yosei; Taima, Tetsuya; Zhou, Ying; Ohashi, Noboru; Kono, Takahiro; Yoshida, Yuji

    2015-11-01

    Bulk heterojunction structures composed of electron donor and acceptor molecules for application in high-performance organic photovoltaics studied. To fabricate these structures, the co-evaporation method in vacuum is commonly applied; however, the details of the crystal growth process during co-evaporation have not yet been established. Here, we focused on structural analysis of blend films composed of phthalocyanine and fullerene based on initial growth stage. Similar crystal growth behavior to that typically observed in single-component molecules is obtained for the films. These results suggest that the competitive crystal growth between donors and acceptors occurs during co-evaporation process. The balance of thin film growth among donor and acceptor molecules can be related to improved photovoltaic performance. The homogeneous blend structure leads to improvement of the power conversion efficiency from 1.2% to 3.0%.

  13. The fabrication and characterization of nano-SQUIDs based on Nb thin films

    NASA Astrophysics Data System (ADS)

    Liu, Xixi; Liu, Xiaoyu; Wang, Hao; Chen, Lei; Wang, Zhen

    2015-08-01

    SQUIDs with nano-junctions (or nano-SQUIDs) are able to be miniaturized into nanoscale to measure a single Bohr magneton. Here, we reported the development of a fabrication process for Nb (niobium) nano-SQUIDs using the thin film deposition and the electron-beam lithography technology. The developed process started from a high-quality superconducting thin film so that it is compatible with a variety of film growing techniques. The as-fabricated nano-SQUIDs exhibited functional flux modulation depth up to 10.3% at 4.6 K, in agreement with the numerical simulation based on the Ginzburg-Landau equation. By further comparing the results from both experiments and simulations, we found that a small critical current below ?50 ?A played a leading role in order to obtain a decent flux-modulation depth for Nb nano-SQUIDs.

  14. AMCC casting development, volume 2

    NASA Technical Reports Server (NTRS)

    1995-01-01

    PCC successfully cast and performed nondestructive testing, FPI and x-ray, on seventeen AMCC castings. Destructive testing, lab analysis and chemical milling, was performed on eleven of the castings and the remaining six castings were shipped to NASA or Aerojet. Two of the six castings shipped, lots 015 and 016, were fully processed per blueprint requirements. PCC has fully developed the gating and processing parameters of this part and feels the part could be implemented into production, after four more castings have been completed to ensure the repeatability of the process. The AMCC casting has been a technically challenging part due to its size, configuration, and alloy type. The height and weight of the wax pattern assembly necessitated the development of a hollow gating system to ensure structural integrity of the shell throughout the investment process. The complexity in the jacket area of the casting required the development of an innovative casting technology that PCC has termed 'TGC' or thermal gradient control. This method of setting up thermal gradients in the casting during solidification represents a significant process improvement for PCC and has been successfully implemented on other programs. The alloy, JBK75, is a relatively new alloy in the investment casting arena and required our engineering staff to learn the gating, processing, and dimensional characteristics of the material.

  15. Enhanced film conductance of silver nanowire-based flexible transparent & conductive networks by bending

    NASA Astrophysics Data System (ADS)

    Xia, Xingda; Yang, Bingchu; Zhang, Xiang; Zhou, Conghua

    2015-07-01

    Bending is usually used to test durability of flexible transparent and conductive films. Due to the large stress incurred by this technique, bending has always been observed to deteriorate conductance of electrodes such as indium tin oxide film. In contrast, we here demonstrate that bending could be used to improve conductance of silver nanowire-based flexible transparent and conductive films. The enhanced conductance is due to improved contact between nanowires, which was favored by the hydrogen bond formed between residential polyvinylpyrrolidone (PVP) on silver nanowire and TiOx nanoparticles pre-coated on the substrate. The enhanced conductance was found to be affected by bending direction; bending towards the substrate not only yielded quicker decrease in sheet resistance, but also showed better film conductance than bending towards the nanowires. Then, with assistance of surface modification of substrate and ultra-long silver nanowires (averaged at 124 ?m, maximum at 438 ?m), optoelectronic performance of 90.2% (transmittance at 550 nm) and 12.5 ? sq-1 (sheet resistance) has been achieved by bending. Such performance was better than commercialized flexible ITO films, and even competed with that obtained from thermal annealing at temperature of 200 °C. Moreover, Fourier transfer infrared (FTIR) spectroscopy study showed strong coordination between C=O (heterocyclic ring of PVP) and silver atoms, showing obvious capping behavior of PVP on silver nanowires.

  16. InGaN-based thin film solar cells: Epitaxy, structural design, and photovoltaic properties

    SciTech Connect

    Sang, Liwen; Liao, Meiyong; Koide, Yasuo; Sumiya, Masatomo

    2015-03-14

    In{sub x}Ga{sub 1?x}N, with the tunable direct bandgaps from ultraviolet to near infrared region, offers a promising candidate for the high-efficiency next-generation thin-film photovoltaic applications. Although the adoption of thick InGaN film as the active region is desirable to obtain efficient light absorption and carrier collection compared to InGaN/GaN quantum wells structure, the understanding on the effect from structural design is still unclear due to the poor-quality InGaN films with thickness and difficulty of p-type doping. In this paper, we comprehensively investigate the effects from film epitaxy, doping, and device structural design on the performances of the InGaN-based solar cells. The high-quality InGaN thick film is obtained on AlN/sapphire template, and p-In{sub 0.08}Ga{sub 0.92}N is achieved with a high hole concentration of more than 10{sup 18?}cm{sup ?3}. The dependence of the photovoltaic performances on different structures, such as active regions and p-type regions is analyzed with respect to the carrier transport mechanism in the dark and under illumination. The strategy of improving the p-i interface by using a super-thin AlN interlayer is provided, which successfully enhances the performance of the solar cells.

  17. Biodegradable multilayer barrier films based on alginate/polyethyleneimine and biaxially oriented poly(lactic acid).

    PubMed

    Gu, Chun-Hong; Wang, Jia-Jun; Yu, Yang; Sun, Hui; Shuai, Ning; Wei, Bing

    2013-02-15

    A layer-by-layer (LBL) approach was used to assemble alternating layers of sodium alginate (ALG)/polyethyleneimine (PEI) on biaxially oriented poly(lactic acid) (BOPLA) films in order to produce bio-based all-polymer thin films with low gas permeability. Increasing the depositing of ALG and PEI from 0 to 30 layers results in large thickness variations (from 0 to 3.92 ?m). After 30 ALG/PEI layers are deposited, the resulting assembly has an OTR of 1.22 cm(3)/(m(2) day atm). When multiplied by thickness, the resulting oxygen permeability (OP) is found to be less than 3.8×10(-17) cm(3) cm/cm(2) s Pa, which is almost 3 orders of magnitude lower than that of uncoated BOPLA film (1.8×10(-14) cm(3)cm/cm(2) s Pa). At the same time, the resulting multilayer-coated BOPLA films maintain high optical clarity and tensile properties. This unique barrier thin film has become a promising alternative to non-biodegradable synthetic food packaging materials. PMID:23399192

  18. Biocompatibility evaluation of sputtered zirconium-based thin film metallic glass-coated steels

    PubMed Central

    Subramanian, Balasubramanian; Maruthamuthu, Sundaram; Rajan, Senthilperumal Thanka

    2015-01-01

    Thin film metallic glasses comprised of Zr48Cu36Al8Ag8 (at.%) of approximately 1.5 ?m and 3 ?m in thickness were prepared using magnetron sputtering onto medical grade 316L stainless steel. Their structural and mechanical properties, in vitro corrosion, and antimicrobial activity were analyzed. The amorphous thin film metallic glasses consisted of a single glassy phase, with an absence of any detectable peaks corresponding to crystalline phases. Elemental composition close to the target alloy was noted from EDAX analysis of the thin film. The surface morphology of the film showed a smooth surface on scanning electron microscopy and atomic force microscopy. In vitro electrochemical corrosion studies indicated that the zirconium-based metallic glass could withstand body fluid, showing superior resistance to corrosion and electrochemical stability. Interactions between the coated surface and bacteria were investigated by agar diffusion, solution suspension, and wet interfacial contact methods. The results indicated a clear zone of inhibition against the growth of microorganisms such as Escherichia coli and Staphylococcus aureus, confirming the antimicrobial activity of the thin film metallic glasses. Cytotoxicity studies using L929 fibroblast cells showed these coatings to be noncytotoxic in nature. PMID:26491304

  19. InGaN-based thin film solar cells: Epitaxy, structural design, and photovoltaic properties

    NASA Astrophysics Data System (ADS)

    Sang, Liwen; Liao, Meiyong; Koide, Yasuo; Sumiya, Masatomo

    2015-03-01

    InxGa1-xN, with the tunable direct bandgaps from ultraviolet to near infrared region, offers a promising candidate for the high-efficiency next-generation thin-film photovoltaic applications. Although the adoption of thick InGaN film as the active region is desirable to obtain efficient light absorption and carrier collection compared to InGaN/GaN quantum wells structure, the understanding on the effect from structural design is still unclear due to the poor-quality InGaN films with thickness and difficulty of p-type doping. In this paper, we comprehensively investigate the effects from film epitaxy, doping, and device structural design on the performances of the InGaN-based solar cells. The high-quality InGaN thick film is obtained on AlN/sapphire template, and p-In0.08Ga0.92N is achieved with a high hole concentration of more than 1018 cm-3. The dependence of the photovoltaic performances on different structures, such as active regions and p-type regions is analyzed with respect to the carrier transport mechanism in the dark and under illumination. The strategy of improving the p-i interface by using a super-thin AlN interlayer is provided, which successfully enhances the performance of the solar cells.

  20. Piezoelectric actuated micro-resonators based on the growth of diamond on aluminum nitride thin films.

    PubMed

    Hees, J; Heidrich, N; Pletschen, W; Sah, R E; Wolfer, M; Williams, O A; Lebedev, V; Nebel, C E; Ambacher, O

    2013-01-18

    Unimorph heterostructures based on piezoelectric aluminum nitride (AlN) and diamond thin films are highly desirable for applications in micro- and nanoelectromechanical systems. In this paper, we present a new approach to combine thin conductive boron-doped as well as insulating nanocrystalline diamond (NCD) with sputtered AlN films without the need for any buffer layers between AlN and NCD or polishing steps. The zeta potentials of differently treated nanodiamond (ND) particles in aqueous colloids are adjusted to the zeta potential of AlN in water. Thereby, the nucleation density for the initial growth of diamond on AlN can be varied from very low (10(8) cm(-2)), in the case of hydrogen-treated ND seeding particles, to very high values of 10(11) cm(-2) for oxidized ND particles. Our approach yielding high nucleation densities allows the growth of very thin NCD films on AlN with thicknesses as low as 40 nm for applications such as microelectromechanical beam resonators. Fabricated piezo-actuated micro-resonators exhibit enhanced mechanical properties due to the incorporation of boron-doped NCD films. Highly boron-doped NCD thin films which replace the metal top electrode offer Young's moduli of more than 1000 GPa. PMID:23220817

  1. Mechanical and barrier properties of guar gum based nano-composite films.

    PubMed

    Saurabh, Chaturbhuj K; Gupta, Sumit; Bahadur, Jitendra; Mazumder, S; Variyar, Prasad S; Sharma, Arun

    2015-06-25

    Guar gum based nano-composite films were prepared using organically modified (cloisite 20A) and unmodified (nanofil 116) nanoclays. Effect of nanoclay incorporation on mechanical strength, water vapor barrier property, chromatic characteristics and opacity of films was evaluated. Nano-composites were characterized using X-ray scattering, FTIR and scanning electron microscopy. A nanoclay concentration dependent increase in mechanical strength and reduction in water vapor transmission rate was observed. Films containing nanofil 116 (2.5% w/w guar gum) and closite 20A (10% w/w guar gum) demonstrated a 102% and 41% higher tensile strength, respectively, as compared to the control. Lower tensile strength of cloisite 20A films as compared to nanofil 116 films was due to its incompatibility with guar gum. X-ray scattering analysis revealed that interstitial spacing between nanofil 116 and cloisite 20A sheets increased due to intercalation by guar gum polymer. This resulted in improved mechanical and barrier properties of nano-composites compared to control. PMID:25839796

  2. Transglutaminase crosslinked pectin- and chitosan-based edible films: a review.

    PubMed

    Porta, Raffaele; Mariniello, Loredana; Di Pierro, Prospero; Sorrentino, Angela; Giosafatto, Concetta Valeria L

    2011-03-01

    The production of biodegradable and edible films with desired mechanical characteristics and gas barrier properties represents one of the most advanced challenges in the field of food wrapping and coating. New edible films can serve not only to provide food with physical protection but also to reduce loss of their moisture, to restrict absorption of oxygen, to lessen migration of lipids, to improve their mechanical handling features, and as materials, to apply in direct contact with internal food to realize a multilayer food packaging. Polymers derived from natural products, like carbohydrates and proteins, offer the greatest opportunities as component of edible films since their biodegradability and environmental compatibility are assured and they can also supplement the nutritional value of specific foods. However, excessive water solubility and poor water vapor barrier properties, and often poor mechanical resistance, have their application limited until the present time. Numerous studies have been carried out to improve their properties by preparing composite and multi-component films or by physically and chemically crosslinking their natural components. In the present review we summarize the main results obtained by crosslinking with the enzyme transglutaminase different proteins contained in multi-component pectin- and chitosan-based edible films, having the aim to create environmentally-friendly "bioplastics" with mechanical and permeability properties similar to the ones exhibited by plastics of petrochemical origin. PMID:21390943

  3. Preparation and characterization agar-based nanocomposite film reinforced by nanocrystalline cellulose.

    PubMed

    Atef, Maryam; Rezaei, Masoud; Behrooz, Rabi

    2014-09-01

    Nanocrystalline cellulose (NCC) was prepared from microcrystalline cellulose (MCC) with particle size of 24.7 ?m using sulfuric acid hydrolysis technique. The obtained NCC revealed size of 0-100 nm, which the major part of them was about 30 nm. Then different contents (2.5, 5 and 10 wt%) of these NCC incorporated in agar film solution and the morphology, structure, and properties of the nanocomposite films were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), Fourier transforms infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), mechanical, physical and optical testing. Results showed that the water vapor permeability (WVP) and water solubility (WS) of the agar-based nanocomposite films significantly (P<0.05) decreased about 13% and 21%, respectively, upon increasing the NCC content to 10%. Tensile strength (TS) and Young's modulus (YM) values of nanocomposite films significantly increased (P?0.05) with addition of NCC, whereas the elongation percent (E%) decreased not significantly (P>0.05). In addition, swelling percentage, transparency and light transmission of the films were decreased by incorporating NCC into polymer matrix. PMID:25036597

  4. Ceramic thick film humidity sensor based on MgTiO{sub 3} + LiF

    SciTech Connect

    Kassas, Ahmad; Bernard, Jérôme; Lelièvre, Céline; Besq, Anthony; Guhel, Yannick; Houivet, David; Boudart, Bertrand; Lakiss, Hassan; Hamieh, Tayssir

    2013-10-15

    Graphical abstract: - Highlights: • The fabricated sensor based on MgTiO{sub 3} + LiF materials used the spin coating technology. • The response time is 70 s to detect variation between 5 and 95% relative humidity. • The addition of Scleroglucan controls the viscosity and decreases the roughness of thick film surface. • This humidity sensor is a promising, low-cost, high-quality, reliable ceramic films, that is highly sensitive to humidity. - Abstract: The feasibility of humidity sensor, consisting of a thick layer of MgTiO{sub 3}/LiF materials on alumina substrate, was studied. The thermal analysis TGA-DTGA and dilatometric analysis worked out to confirm the sintering temperature. An experimental plan was applied to describe the effects of different parameters in the development of the thick film sensor. Structural and microstructural characterizations of the developed thick film were made. Rheological study with different amounts of a thickener (scleroglucan “sclg”), showing the behavior variation, as a function of sclg weight % was illustrated and rapprochement with the results of thickness variation as a function of angular velocity applied in the spin coater. The electrical and dielectric measurements confirmed the sensitivity of the elaborated thick film against moisture, along with low response time.

  5. Cross-species extrapolation of mammalian-based ToxCast Data using Sequence Alignment to Predict Across Species Susceptibility (SeqAPASS)

    EPA Science Inventory

    In vitro high-throughput screening (HTS) and in silico technologies have emerged as 21st century tools for chemical hazard identification. In 2007 the U.S. Environmental Protection Agency (EPA) launched the ToxCast Program, which has screened thousands of chemicals in hundreds of...

  6. Comparison of diverse nanomaterial bioactivity profiles based on high-throughput screening (HTS) in ToxCast™ (FutureToxII)

    EPA Science Inventory

    Most nanomaterials (NMs) in commerce lack hazard data. Efficient NM testing requires suitable toxicity tests for prioritization of NMs to be tested. The EPA’s ToxCast program is screening NM bioactivities and ranking NMs by their bioactivities to inform targeted testing planning....

  7. Preparation and characterization of biodegradable active PLA film for food packaging

    NASA Astrophysics Data System (ADS)

    Di Maio, L.; Scarfato, P.; Avallone, E.; Galdi, M. R.; Incarnato, L.

    2014-05-01

    In this work we report on the preparation and characterization of a biodegradable active PLA film (aPLA), intended for food packaging applications. The film was obtained by cast extrusion blending a commercial PLA matrix with an active system, developed in our laboratory and based on PLA microparticles containing a-tocopherol (aTCP) as natural antioxidant agent. In order to optimize the film composition and processing, the active microparticles were preliminarily characterized with the aim to evaluate their morphology (size and shape), thermal resistance and a-tocopherol content. The aPLA film, produced with a 5wt% of aTCP, was characterized in terms of performance and activity. The experimental results demonstrated that the aPLA film has mechanical, thermal, barrier and optical properties adequate for packaging applications and shows oxygen scavenging activity and prolonged exhaustion lag time, compared to pure PLA films.

  8. Sputtered silver films to improve chromium carbide based solid lubricant coatings for use to 900 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Sliney, Harold E.; Deadmore, Daniel L.

    1988-01-01

    Thin silver films, 250 to 3500 A thick, were sputtered onto PS200, a plasma sprayed, chromium carbide based solid lubricant coating, to reduce run-in wear and improve tribological properties. The coating contains bonded chromium carbide as the wear resistant base stock with silver and barium fluoride/calcium fluoride eutectic added as low and high temperature lubricants, respectively. Potential applications for the PS200 coating are cylinder wall/piston ring lubrication for Stirling engines and foil bearing journal lubrication. In this preliminary program, the silver film overlay thickness was optimized based on tests using a pin-on-disk tribometer. The friction and wear studies were performed in a helium atmosphere at temperatures from 25 to 760 C with a sliding velocity of 2.7 m/s under a 4.9 N load. Films between 1000 and 1500 A provide the best lubrication of the counterface material. The films enrich the sliding surface with lubricant and reduce the initial abrasiveness of the as ground, plasma-sprayed coating surface, thus reducing wear.

  9. Sputtered silver films to improve chromium carbide based solid lubricant coatings for use to 900 C

    NASA Technical Reports Server (NTRS)

    Dellacorte, Christopher; Sliney, Harold E.; Deadmore, Daniel L.

    1988-01-01

    Thin silver films, 250 to 3500 A thick, were sputtered onto PS200, a plasma sprayed, chromium carbide based solid lubricant coating, to reduce run-in wear and improve tribological properties. The coating contains bonded chromium carbide as the wear resistant base stock with silver and barium fluoride/calcium fluoride eutectic added as low and high temperature lubricants respectively. Potential applications for the PS200 coating are cylinder wall/piston ring lubrication for Stirling engines and foil bearing journal lubrication. In this preliminary program, the silver film overlay thickness was optimized based on tests using a pin-on-disk tribometer. The friction and wear studies were performed in a helium atmosphere at temperatures from 25 to 760 C with a sliding velocity of 2.7 m/s under a 4.9 N load. Films between 1000 and 1500 A provide the best lubrication of the counterface material. The films enrich the sliding surface with lubricant and reduce the initial abrasiveness of the as ground, plasma-sprayed coating surface, thus reducing wear.

  10. Oxygen evolution mediated by co-based thin film electrocatalysts

    E-print Network

    Surendranath, Yogesh

    2011-01-01

    The electrocatalytic conversion of water to O? is the key efficiency-determining reaction for the storage of electrical energy in the form of liquid fuels. In this thesis, the simple preparation of a cobalt-based catalyst ...

  11. SU-F-18C-10: Clinical Implementation of Radiochromic Film Based CTDI Measurements

    SciTech Connect

    Quintero, C; Seuntjens, J; Devic, S; Tomic, N; DeBlois, F

    2014-06-15

    Purpose: To evaluate accuracy and reproducibility of a radiochromic film-based protocol to measure computer tomography dose index (CTDI) as a part of annual QA on CT scanners and kV CBCT systems attached to linear accelerators. Methods: Energy dependence of Gafchromic XR-QA2(R) film model was tested over imaging beam qualities (50 – 140 kVp). Film pieces were irradiated in air to known values of air kerma in air (up to 10 cGy). Change in film reflectance was determined with an in-house written code using images produced by a flatbed document scanner. Calibration curves for each beam quality were created, and film responses for same air-kerma values were compared.Sets of film strips were placed into holes of a CTDI phantom and irradiated for several clinical scanning protocols on CT-simulators and CBCT systems. Film reflectance change was converted into dose to water and used to calculate CTDIvol values. Measured CTDIvol values were compared to tabulated CTDIvol values. Results: Average variations of ±5.2% in the mean film reflectance change were observed in the energy range of 80 to 140 keV, and 11.1% between 50 and 140 keV. The averaged measured CTDI values presented a mean variation for the same machine and protocol of 2.6%. However, measured CTDI values were in average 10% lower than tabulated CTDI values for CT-simulators, and 44% higher for CBCT systems. Conclusion: We found that in relatively broad range of beam qualities used in diagnostic radiology variation of film response is within ±5% resulting in ±15% systematic error in dose estimates if a single calibration curve is used. Relatively large discrepancy between measured and tabulated CTDI values for different protocols and imaging systems used within radiotherapy department strongly support the trend towards replacing CTDI value with equilibrium dose measurement in the center of cylindrical phantom as suggested by TG-111. This work was supported by the Natural Sciences and Engineering Research Council of Canada, Contract No. 386009; Partial support by CREATE, Medical Physics Research Training Network grant of the Natural Science and Engineering Research Council, Contract No. 432290.

  12. Solid-State Densification of Spun-Cast Self-Assembled Monolayers for Use in Ultra-Thin Hybrid Dielectrics

    PubMed Central

    Hutchins, Daniel O.; Acton, Orb; Weidner, Tobias; Cernetic, Nathan; Baio, Joe E.; Castner, David G.; Ma, Hong; Jen, Alex K.-Y.

    2013-01-01

    Ultra-thin self-assembled monolayer (SAM)-oxide hybrid dielectrics have gained significant interest for their application in low-voltage organic thin film transistors (OTFTs). A [8-(11-phenoxy-undecyloxy)-octyl]phosphonic acid (PhO-19-PA) SAM on ultrathin AlOx (2.5 nm) has been developed to significantly enhance the dielectric performance of inorganic oxides through reduction of leakage current while maintaining similar capacitance to the underlying oxide structure. Rapid processing of this SAM in ambient conditions is achieved by spin coating, however, as-cast monolayer density is not sufficient for dielectric applications. Thermal annealing of a bulk spun-cast PhO-19-PA molecular film is explored as a mechanism for SAM densification. SAM density, or surface coverage, and order are examined as a function of annealing temperature. These SAM characteristics are probed through atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and near edge X-ray absorption fine structure spectroscopy (NEXAFS). It is found that at temperatures sufficient to melt the as-cast bulk molecular film, SAM densification is achieved; leading to a rapid processing technique for high performance SAM-oxide hybrid dielectric systems utilizing a single wet processing step. To demonstrate low-voltage devices based on this hybrid dielectric (with leakage current density of 7.7×10?8 A cm?2 and capacitance density of 0.62 µF cm?2 at 3 V), pentacene thin-film transistors (OTFTs) are fabricated and yield sub 2 V operation and charge carrier mobilites of up to 1.1 cm2 V?1 s?1. PMID:24288423

  13. FILMING OF 'CONTACT' AT LC39 PRESS SITE WITH VAB IN BACKGROUND

    NASA Technical Reports Server (NTRS)

    1997-01-01

    With the Vehicle Assembly Building looming in the background, 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.

  14. FILMING OF 'CONTACT' AT LC39 PRESS SITE SEEN FROM VAB ROOF

    NASA Technical Reports Server (NTRS)

    1997-01-01

    The filming of scenes for the movie 'Contact' by Warner Bros.' cast and crew at Kennedy Space Center's Launch Complex 39 Press Site on January 29 is captured by cameras on the roof of the Vehicle Assembly Building. 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.

  15. FILMING OF 'CONTACT' AT LC39 PRESS SITE WITH VAB IN BACKGROUND

    NASA Technical Reports Server (NTRS)

    1997-01-01

    With the Vehicle Assembly Building looming in the background, 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.

  16. Extrusion cast explosive

    DOEpatents

    Scribner, K.J.

    1985-01-29

    Improved, multiphase, high performance, high energy, extrusion cast explosive compositions, comprising, a crystalline explosive material; an energetic liquid plasticizer; a urethane prepolymer, comprising a blend of polyvinyl formal, and polycaprolactone; a polyfunctional isocyanate; and a catalyst are disclosed. These new explosive compositions exhibit higher explosive content, a smooth detonation front, excellent stability over long periods of storage, and lower sensitivity to mechanical stimulants. 1 fig.

  17. Extrusion cast explosive

    DOEpatents

    Scribner, K.J.

    1985-11-26

    Disclosed is an improved, multiphase, high performance, high energy, extrusion cast explosive compositions, comprising, a crystalline explosive material; an energetic liquid plasticizer; a urethane prepolymer, comprising a blend of polyvinyl formal, and polycaprolactone; a polyfunctional isocyanate; and a catalyst. These new explosive compositions exhibit higher explosive content, a smooth detonation front, excellent stability over long periods of storage, and lower sensitivity to mechanical stimulants. 1 fig.

  18. Computer cast blast modelling

    SciTech Connect

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

    1994-12-31

    Cast blasting can be designed to utilize explosive energy effectively and economically for coal mining operations to remove overburden material. This paper compares two blast models known as DMC (Distinct Motion Code) and SABREX (Scientific Approach to Breaking Rock with Explosives). DMC applies discrete spherical elements interacted with the flow of explosive gases and the explicit time integration to track particle motion resulting from a blast. The input to this model includes multi-layer rock properties, and both loading geometry and explosives equation-of-state parameters. It enables the user to have a wide range of control over drill pattern and explosive loading design parameters. SABREX assumes that heave process is controlled by the explosive gases which determines the velocity and time of initial movement of blocks within the burden, and then tracks the motion of the blocks until they come to a rest. In order to reduce computing time, the in-flight collisions of blocks are not considered and the motion of the first row is made to limit the motion of subsequent rows. Although modelling a blast is a complex task, the advance in computer technology has increased the computing power of small work stations as well as PC (personal computers) to permit a much shorter turn-around time for complex computations. The DMC can perform a blast simulation in 0.5 hours on the SUN SPARC station 10-41 while the new SABREX 3.5 produces results of a cast blast in ten seconds on a 486-PC. Predicted percentage of cast and face velocities from both computer codes compare well with the measured results from a full scale cast blast.

  19. Carbon-based layer-by-layer nanostructures: from films to hollow capsules

    NASA Astrophysics Data System (ADS)

    Hong, Jinkee; Han, Jung Yeon; Yoon, Hyunsik; Joo, Piljae; Lee, Taemin; Seo, Eunyong; Char, Kookheon; Kim, Byeong-Su

    2011-11-01

    Over the past years, the layer-by-layer (LbL) assembly has been widely developed as one of the most powerful techniques to prepare multifunctional films with desired functions, structures and morphologies because of its versatility in the process steps in both material and substrate choices. Among various functional nanoscale objects, carbon-based nanomaterials, such as carbon nanotubes and graphene sheets, are promising candidates for emerging science and technology with their unique physical, chemical, and mechanical properties. In particular, carbon-based functional multilayer coatings based on the LbL assembly are currently being actively pursued as conducting electrodes, batteries, solar cells, supercapacitors, fuel cells and sensor applications. In this article, we give an overview on the use of carbon materials in nanostructured films and capsules prepared by the LbL assembly with the aim of unraveling the unique features and their applications of carbon multilayers prepared by the LbL assembly.

  20. In situ-grown hexagonal silicon nanocrystals in silicon carbide-based films

    PubMed Central

    2012-01-01

    Silicon nanocrystals (Si-NCs) were grown in situ in carbide-based film using a plasma-enhanced chemical vapor deposition method. High-resolution transmission electron microscopy indicates that these nanocrystallites were embedded in an amorphous silicon carbide-based matrix. Electron diffraction pattern analyses revealed that the crystallites have a hexagonal-wurtzite silicon phase structure. The peak position of the photoluminescence can be controlled within a wavelength of 500 to 650 nm by adjusting the flow rate of the silane gas. We suggest that this phenomenon is attributed to the quantum confinement effect of hexagonal Si-NCs in silicon carbide-based film with a change in the sizes and emission states of the NCs. PMID:23171576

  1. Flexible thin-film PVDF-TrFE based pressure sensor for smart catheter applications.

    PubMed

    Sharma, Tushar; Aroom, Kevin; Naik, Sahil; Gill, Brijesh; Zhang, John X J

    2013-04-01

    We demonstrate the design of thin flexible pressure sensors based on piezoelectric PVDF-TrFE (polyvinyledenedifluoride-tetrafluoroethylene) co-polymer film, which can be integrated onto a catheter, where the compact inner lumen space limit the dimensions of the pressure sensors. Previously, we demonstrated that the thin-film sensors of one micrometer thickness were shown to have better performance compared to the thicker film with no additional electrical poling or mechanical stretching due to higher crystallinity. The pressure sensors can be mass producible using standard lithography process, with excellent control of film uniformity and thickness down to one micrometer. The fabricated pressure sensors were easily mountable on external surface of commercial catheters. Elaborate experiments were performed to demonstrate the applicability of PVDF sensors towards catheter based biomedical application. The resonant frequency of the PVDF sensor was found to be 6.34 MHz. The PVDF sensors can operate over a broad pressure range of 0-300 mmHg. The average sensitivity of the PVDF sensor was found to be four times higher (99 ?V/mmHg) than commercial pressure sensor while the PVDF sensor (0.26 s) had fivefold shorter response time than commercial pressure sensor (1.30 s), making the PVDF sensors highly suitable for real-time pressure measurements using catheters. PMID:23519532

  2. Iron-based inorganic-organic hybrid and superlattice thin films by ALD/MLD.

    PubMed

    Tanskanen, A; Karppinen, M

    2015-11-28

    Here we present novel layer-by-layer deposition processes for the fabrication of inorganic-organic hybrid thin films of the (-Fe-O-C6H4-O-)n type and also superlattices where thicker iron oxide layers alternate with monomolecular-thin organic layers. The processes are based on a combination of atomic layer deposition (ALD) and molecular layer deposition (MLD) techniques where the cyclopentadienyl iron dicarbonyl dimer (Cp2Fe2(CO)4) is used as the iron source and hydroquinone (HQ) as the organic precursor. For the (-Fe-O-C6H4-O-)n hybrid films a growth rate value as high as 3.7 Å per cycle was achieved at 180 °C. Superlattices where thin crystalline iron oxide layers of the magnetite structure alternate with single organic layers consisting of benzene rings were moreover successfully fabricated from the same precursors at 160 °C using water as the source of oxygen in the ALD cycles for the magnetite layers. We foresee that our new ALD/MLD processes offer a valuable novel tool to modify the properties of magnetite thin films and even more widely possess the potential to boost the ALD/MLD research frontier on functional transition metal oxide based thin films. PMID:26486269

  3. Thin and Thick Films Materials Based Interconnection Technology for 500 C Operation

    NASA Technical Reports Server (NTRS)

    Chen, Liang-Yu; Hunter, Gary W.; Neudeck, Philip G.

    2000-01-01

    Precious metal based thick-film material was used for printed wires, wire bond pads, test lead-attach, and conductive die-attach for high temperature (up to 500 C and beyond) chip level packaging. A SiC Shottky diode with a thin-film coated backside was attached to a ceramic substrate using precious metal based thick-film material as the electrically conductive bonding layer. After a 500-hour soak test in atmospheric oxygen, these basic interconnection elements, including attached test diode survived both electrically and mechanically. The electrical resistance of these interconnections (including thick-film printed wire/pad, bonded wire, and test lead attach) were low and stable at both room and elevated temperatures. The electrical resistance of the die-attach interface estimated by I-V characterization of the attached diode, during and after high temperature heat treatment, remained desirably low over the course of a 500-hour anneal. Further durability testing of this high temperature interconnection technology is also discussed.

  4. Thin-film encapsulation of the air-sensitive organic-based ferrimagnet vanadium tetracyanoethylene

    SciTech Connect

    Froning, I. H.; Harberts, M.; Yu, H.; Johnston-Halperin, E.; Lu, Y.; Epstein, A. J.

    2015-03-23

    The organic-based ferrimagnet vanadium tetracyanoethylene (V[TCNE]{sub x?2}) has demonstrated potential for use in both microwave electronics and spintronics due to the combination of high temperature magnetic ordering (T{sub C}?>?600?K), extremely sharp ferromagnetic resonance (peak to peak linewidth of 1?G), and low-temperature conformal deposition via chemical vapor deposition (deposition temperature of 50?°C). However, air-sensitivity leads to the complete degradation of the films within 2?h under ambient conditions, with noticeable degradation occurring within 30 min. Here, we demonstrate encapsulation of V[TCNE]{sub x?2} thin films using a UV-cured epoxy that increases film lifetime to over 710 h (30 days) as measured by the remanent magnetization. The saturation magnetization and Curie temperature decay more slowly than the remanence, and the coercivity is unchanged after 340 h (14 days) of air exposure. Fourier transform infrared spectroscopy indicates that the epoxy does not react with the film, and magnetometry measurements show that the presence of the epoxy does not degrade the magnetic properties. This encapsulation strategy directly enables a host of experimental protocols and investigations not previously feasible for air-sensitive samples and lays the foundation for the development of practical applications for this promising organic-based magnetic material.

  5. Thin-film encapsulation of the air-sensitive organic-based ferrimagnet vanadium tetracyanoethylene

    NASA Astrophysics Data System (ADS)

    Froning, I. H.; Harberts, M.; Lu, Y.; Yu, H.; Epstein, A. J.; Johnston-Halperin, E.

    2015-03-01

    The organic-based ferrimagnet vanadium tetracyanoethylene (V[TCNE]x˜2) has demonstrated potential for use in both microwave electronics and spintronics due to the combination of high temperature magnetic ordering (TC > 600 K), extremely sharp ferromagnetic resonance (peak to peak linewidth of 1 G), and low-temperature conformal deposition via chemical vapor deposition (deposition temperature of 50 °C). However, air-sensitivity leads to the complete degradation of the films within 2 h under ambient conditions, with noticeable degradation occurring within 30 min. Here, we demonstrate encapsulation of V[TCNE]x˜2 thin films using a UV-cured epoxy that increases film lifetime to over 710 h (30 days) as measured by the remanent magnetization. The saturation magnetization and Curie temperature decay more slowly than the remanence, and the coercivity is unchanged after 340 h (14 days) of air exposure. Fourier transform infrared spectroscopy indicates that the epoxy does not react with the film, and magnetometry measurements show that the presence of the epoxy does not degrade the magnetic properties. This encapsulation strategy directly enables a host of experimental protocols and investigations not previously feasible for air-sensitive samples and lays the foundation for the development of practical applications for this promising organic-based magnetic material.

  6. Modeling of casting microstructures and defects

    SciTech Connect

    Shapiro, A.B.; Summers, L.T.; Eckels, D.J.; Sahai, V.

    1997-09-26

    Casting is an ancient art that has been a trial-and-error process for more than 4000 years. To predict the size, shape, and quality of a cast product, casting manufacturers typically cast full-size prototypes. If one part of the process is done incorrectly, the entire process is repeated until an acceptable product is achieved. One way to reduce the time, cost, and waste associated with casting is to use computer modeling to predict not only the quality of a product on the macro- scale, such as distortion and part shape, but also on the micro-scale such as grain defects. Modeling of solidification is becoming increasingly feasible with the advent of parallel computers. There are essentially two approaches to solidification modeling.The first is that of macro-modeling where heat transfer codes model latent heat release during solidification as a constant and based solely on the local temperature. This approach is useful in predicting large scale distortion and final part shape. The second approach, micro-modeling, is more fundamental. The micro-models estimate the latent heat release during solidification using nucleation and grain growth kinetics. Micro-models give insight into cast grain morphology and show promise in the future to predict engineering properties such as tensile strength. The micro-model solidification kinetics can be evaluated using first principles or they can be evaluated using experiments. This work describes an implementation of a micro-model for uranium which uses experimental results to estimate nucleation and growth kinetics.

  7. Wound healing efficacy of a chitosan-based film-forming gel containing tyrothricin in various rat wound models.

    PubMed

    Kim, Ju-Young; Jun, Joon-Ho; Kim, Sang-Joon; Hwang, Kyu-Mok; Choi, Sung Rak; Han, Sang Duk; Son, Mi-Won; Park, Eun-Seok

    2015-02-01

    The objective of this study was to evaluate the healing effects of a chitosan-based, film-forming gel containing tyrothricin (TYR) in various rat wound models, including burn, abrasion, incision, and excision models. After solidification, the chitosan film layer successfully covered and protected a variety of wounds. Wound size was measured at predetermined timepoints after wound induction, and the effects of the film-forming gel were compared with negative (no treatment) and positive control groups (commercially available sodium fusidate ointment and TYR gel). In burn, abrasion and excision wound models, the film-forming gel enabled significantly better healing from 1 to 6 days after wound induction, compared with the negative control. Importantly, the film-forming gel also enabled significantly better healing compared with the positive control treatments. In the incision wound model, the breaking strength of wound strips from the group treated with the film-forming gel was significantly increased compared with both the negative and positive control groups. Histological studies revealed advanced granulation tissue formation and epithelialization in wounds treated with the film-forming gel. We hypothesize that the superior healing effects of the film-forming gel are due to wound occlusion, conferred by the chitosan film. Our data suggest that this film-forming gel may be useful in treating various wounds, including burn, abrasion, incision and excision wounds. PMID:24715576

  8. Optical rotatory dispersion and circular dichroism of the films based on chitosan in the form of polysalts and polybases

    NASA Astrophysics Data System (ADS)

    Malinkina, Olga N.; Shipovskaya, Anna B.; Kazmicheva, Olga F.

    2015-03-01

    The surface morphology and optical activity of films based on chitosan in different chemical forms were investigated by methods of scanning electron and atomic force microscopy, spectropolarimetry. These film samples are used as substrates for optical waveguides, sorption material and as substrates for cell culturing tissue-engineering and scaffold constructions. The essential differences in the structural and morphological relief of thin films from chitosan of different chemical forms are established. It was found that the spectra of optical rotatory dispersion and circular dichroism of films of chitosan in the form of polysalts and polybases are significantly different in absolute values of the optical rotation of the plane and circularly polarized light.

  9. Magnetic Properties of FeNi-Based Thin Film Materials with Different Additives

    PubMed Central

    Liang, Cai; Gooneratne, Chinthaka P.; Wang, Qing Xiao; Liu, Yang; Gianchandani, Yogesh; Kosel, Jurgen

    2014-01-01

    This paper presents a study of FeNi-based thin film materials deposited with Mo, Al and B using a co-sputtering process. The existence of soft magnetic properties in combination with strong magneto-mechanical coupling makes these materials attractive for sensor applications. Our findings show that FeNi deposited with Mo or Al yields magnetically soft materials and that depositing with B further increases the softness. The out-of-plane magnetic anisotropy of FeNi thin films is reduced by depositing with Al and completely removed by depositing with B. The effect of depositing with Mo is dependent on the Mo concentration. The coercivity of FeNiMo and FeNiAl is reduced to less than a half of that of FeNi, and a value as low as 40 A/m is obtained for FeNiB. The surfaces of the obtained FeNiMo, FeNiAl and FeNiB thin films reveal very different morphologies. The surface of FeNiMo shows nano-cracks, while the FeNiAl films show large clusters and fewer nano-cracks. When FeNi is deposited with B, a very smooth morphology is obtained. The crystal structure of FeNiMo strongly depends on the depositant concentration and changes into an amorphous structure at a higher Mo level. FeNiAl thin films remain polycrystalline, even at a very high concentration of Al, and FeNiB films are amorphous, even at a very low concentration of B. PMID:25587418

  10. Properties of solid solutions, doped film, and nanocomposite structures based on zinc oxide

    NASA Astrophysics Data System (ADS)

    Lashkarev, G. V.; Shtepliuk, I. I.; Ievtushenko, A. I.; Khyzhun, O. Y.; Kartuzov, V. V.; Ovsiannikova, L. I.; Karpyna, V. A.; Myroniuk, D. V.; Khomyak, V. V.; Tkach, V. N.; Timofeeva, I. I.; Popovich, V. I.; Dranchuk, N. V.; Khranovskyy, V. D.; Demydiuk, P. V.

    2015-02-01

    A study of the properties of materials based on the wide bandgap zinc oxide semiconductor, which are promising for application in optoelectronics, photovoltaics and nanoplasmonics. The structural and optical properties of solid solution Zn1-xCdxO films with different cadmium content, are studied. The samples are grown using magnetron sputtering on sapphire backing. Low-temperature photoluminescence spectra revealed emission peaks associated with radiative recombination processes in those areas of the film that have varying amounts of cadmium. X-ray phase analysis showed the presence of a cadmium oxide cubic phase in these films. Theoretical studies of the solid solution thermodynamic properties allowed for a qualitative interpretation of the observed experimental phenomena. It is established that the growth of the homogeneous solid solution film is possible only at high temperatures, whereas regions of inhomogeneous composition can be narrowed through elastic deformation, caused by the mismatch of the film-backing lattice constants. The driving forces of the spinodal decomposition of the Zn1-xCdxO system are identified. Fullerene-like clusters of Znn-xCdxOn are used to calculate the bandgap and the cohesive energy of ZnCdO solid solutions. The properties of transparent conductive ZnO films, doped with Group III donor impurities (Al, Ga, In), are examined. It is shown that oxygen vacancies are responsible for the hole trap centers in the zinc oxide photoconductivity process. We also examine the photoluminescence properties of metal-ZnO nanocomposite structures, caused by surface plasmons.

  11. Sputtered Molybdenum Bilayer Back Contact for Copper Indium Diselenide-Based Polycrystalline Thin-Film Solar Cells

    E-print Network

    Scofield, John H.

    Sputtered Molybdenum Bilayer Back Contact for Copper Indium Diselenide-Based Polycrystalline Thin) A method is described for fabricating low-resistivity molybdenum films on soda-lime glass substrates-thick molybdenum bilayers have been fabricated with both low resistivity (12-14 µcm) and good adhesion. These films

  12. Optimal antimicrobial formulation and physical-mechanical properties of edible films based on Açaí and Pectin for food preservation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    This work aimed to develop edible films based on pectin and açaí. Films were incorporated with apple skin polyphenols (ASP) and thyme essential oil (TEO) according to the central composite design. Antimicrobial optimal formulation was determined using the response surface methodology and desirabilit...

  13. The development of potassium tantalate niobate thin films for satellite-based pyroelectric detectors

    SciTech Connect

    Cherry, H B.B.

    1997-05-01

    Potassium tantalate niobate (KTN) pyroelectric detectors are expected to provide detectivities, of 3.7 x 10{sup 11} cmHz {sup {1/2}}W{sup {minus}1} for satellite-based infrared detection at 90 K. The background limited detectivity for a room-temperature thermal detector is 1.8 x 10{sup 10} cmHz{sup {1/2}}W{sup {minus}1}. KTN is a unique ferroelectric for this application because of the ability to tailor the temperature of its pyroelectric response by adjusting its ratio of tantalum to niobium. The ability to fabricate high quality KTN thin films on Si-based substrates is crucial to the development of KTN pyroelectric detectors. Si{sub x}N{sub y} membranes created on the Si substrate will provide the weak thermal link necessary to reach background limited detectivities. The device dimensions obtainable by thin film processing are expected to increase the ferroelectric response by 20 times over bulk fabricated KTN detectors. In addition, microfabrication techniques allow for easier array development. This is the first reported attempt at growth of KTN films on Si-based substrates. Pure phase perovskite films were grown by pulsed laser deposition on SrRuO{sub 3}/Pt/Ti/Si{sub x}N{sub y}/Si and SrRuO{sub 3}/Si{sub x}N{sub y}/Si structures; room temperature dielectric permittivities for the KTN films were 290 and 2.5, respectively. The dielectric permittivity for bulk grown, single crystal KTN is {approximately}380. In addition to depressed dielectric permittivities, no ferroelectric hysteresis was found between 80 and 300 K for either structure. RBS, AES, TEM and multi-frequency dielectric measurements were used to investigate the origin of this apparent lack of ferroelectricity. Other issues addressed by this dissertation include: the role of oxygen and target density during pulsed laser deposition of KTN thin films; the use of YBCO, LSC and Pt as direct contact bottom electrodes to the KTN films, and the adhesion of the bottom electrode layers to Si{sub x}N{sub y}/Si.

  14. The development of potassium tantalate niobate thin films for satellite-based pyroelectric detectors

    NASA Astrophysics Data System (ADS)

    Cherry, Hilary Beatrix Baumann

    Potassium tantalate niobate (KTN) pyroelectric detectors are expected to provide detectivities of 3.7× 10sp{11}\\ cmHzsp{1/2}Wsp{-1} for satellite-based infrared detection at 90 K. The background limited detectivity for a room-temperature thermal detector is 1.8× 10sp{10}\\ cmHzsp{1/2}Wsp{-1}. KTN is a unique ferroelectric for this application because of the ability to tailor the temperature of its pyroelectric response by adjusting its ratio of tantalum to niobium. The ability to fabricate high quality KTN thin films on Si-based substrates is crucial to the development of KTN pyroelectric detectors. Sisb{x}Nsb{y} membranes created on the Si substrate will provide the weak thermal link necessary to reach background limited detectivities. The device dimensions obtainable by thin film processing are expected to increase the ferroelectric response by 20 times over bulk fabricated KTN detectors. In addition, microfabrication techniques allow for easier array development. This is the first reported attempt at growth of KTN films on Si-based substrates. Pure phase perovskite films were grown by pulsed laser deposition on SrRuOsb3/Pt/Ti/Sisb{x}Nsb{y}/Si and SrRuOsb3/Sisb{x}Nsb{y}/Si structures; room temperature dielectric permittivities for the KTN films were 290 and 2.5, respectively. The dielectric permittivity for bulk grown, single crystal KTN is {˜}380. In addition to depressed dielectric permittivities, no ferroelectric hysteresis was found between 80 and 300 K for either structure. RBS, AES, TEM and multi-frequency dielectric measurements were used to investigate the origin of this apparent lack of ferroelectricity. The most likely explanation is the presence of point defects. Other issues addressed by this dissertation include: the role of oxygen and target density during pulsed laser deposition of KTN thin films; the use of YBCO, LSC and Pt as direct contact bottom electrodes to the KTN films, the adhesion of the bottom electrode layers to Sisb{x}Nsb{y}/Si and the top electrode adhesion.

  15. Characteristics of ultra low-k nanoporous and fluorinated silica based films prepared by plasma enhanced chemical vapor deposition

    SciTech Connect

    Abbasi-Firouzjah, M.; Shokri, B.; Physics Department, Shahid Beheshti University G.C., Evin, Tehran

    2013-12-07

    Low dielectric constant (low-k) silica based films were deposited on p-type silicon and polycarbonate substrates by radio frequency (RF) plasma enhanced chemical vapor deposition method at low temperature. A mixture of tetraethoxysilane vapor, oxygen, and tetrafluoromethane (CF{sub 4}) was used for the deposition of the films in forms of two structures called as SiO{sub x}C{sub y} and SiO{sub x}C{sub y}F{sub z}. Properties of the films were controlled by amount of porosity and fluorine content in the film matrix. The influence of RF power and CF{sub 4} flow on the elemental composition, deposition rate, surface roughness, leakage current, refractive index, and dielectric constant of the films were characterized. Moreover, optical emission spectroscopy was applied to monitor the plasma process at the different parameters. Electrical characteristics of SiO{sub x}C{sub y} and SiO{sub x}C{sub y}F{sub z} films with metal-oxide-semiconductor structure were investigated using current-voltage analysis to measure the leakage current and breakdown field, as well as capacitance-voltage analysis to obtain the film's dielectric constant. The results revealed that SiO{sub x}C{sub y} films, which are deposited at lower RF power produce more leakage current, meanwhile the dielectric constant and refractive index of these films decreased mainly due to the more porosity in the film structure. By adding CF{sub 4} in the deposition process, fluorine, the most electronegative and the least polarized atom, doped into the silica film and led to decrease in the refractive index and the dielectric constant. In addition, no breakdown field was observed in the electrical characteristics of SiO{sub x}C{sub y}F{sub z} films and the leakage current of these films reduced by increment of the CF{sub 4} flow.

  16. Characteristics of ultra low-k nanoporous and fluorinated silica based films prepared by plasma enhanced chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Abbasi-Firouzjah, M.; Shokri, B.

    2013-12-01

    Low dielectric constant (low-k) silica based films were deposited on p-type silicon and polycarbonate substrates by radio frequency (RF) plasma enhanced chemical vapor deposition method at low temperature. A mixture of tetraethoxysilane vapor, oxygen, and tetrafluoromethane (CF4) was used for the deposition of the films in forms of two structures called as SiOxCy and SiOxCyFz. Properties of the films were controlled by amount of porosity and fluorine content in the film matrix. The influence of RF power and CF4 flow on the elemental composition, deposition rate, surface roughness, leakage current, refractive index, and dielectric constant of the films were characterized. Moreover, optical emission spectroscopy was applied to monitor the plasma process at the different parameters. Electrical characteristics of SiOxCy and SiOxCyFz films with metal-oxide-semiconductor structure were investigated using current-voltage analysis to measure the leakage current and breakdown field, as well as capacitance-voltage analysis to obtain the film's dielectric constant. The results revealed that SiOxCy films, which are deposited at lower RF power produce more leakage current, meanwhile the dielectric constant and refractive index of these films decreased mainly due to the more porosity in the film structure. By adding CF4 in the deposition process, fluorine, the most electronegative and the least polarized atom, doped into the silica film and led to decrease in the refractive index and the dielectric constant. In addition, no breakdown field was observed in the electrical characteristics of SiOxCyFz films and the leakage current of these films reduced by increment of the CF4 flow.

  17. An overview of film-based microsensors and applications

    SciTech Connect

    Pfeifer, K.B.; Butler, M.A.; Hughes, R.C.

    1995-12-31

    Many chemical analysis problems exist that encourage the development of small, low-cost, low power, chemical sensors in many of these applications, while speciation of the sample is unnecessary due to prior knowledge of the sample constituents, it is necessary to monitor, in near real-time, the concentration of a Particular species of interest, An example of this of problem would be the monitoring of a chemical process such as steam reforming of chemical waste or ground water monitoring where prior laboratory analysis has determined the constituents. In applications such as these, it is worthwhile to trade off the sensitivity and speciation that can be obtained by taking individual samples and analyzing them in a laboratory for the near real-time, low-cost measurements that can be achieved using a solid-state transducer. In this paper, several different types of sensor platforms and applications that require CSFs bonded to the platform will be discussed. Among these are surface acoustic wave (SAW) based sensors, optical fiber-based sensors, and Si-based sensors. Each will be described and applications will be discussed.

  18. Sculpture, detail view of cast iron lamps, with scale (note: ...

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

    Sculpture, detail view of cast iron lamps, with scale (note: "'J.L. Mott, Ironworks, NY" stamp on the base) - National Park Seminary, Bounded by Capitol Beltway (I-495), Linden Lane, Woodstove Avenue, & Smith Drive, Silver Spring, Montgomery County, MD

  19. LOST FOAM CASTING OF MAGNESIUM ALLOYS

    SciTech Connect

    Han, Qingyou; Dinwiddie, Ralph Barton; Sklad, Philip S; Currie, Kenneth; Abdelrahman, Mohamed; Vondra, Fred; Walford, Graham; Nolan, Dennis J

    2007-01-01

    The lost foam casting process has been successfully used for making aluminum and cast iron thin walled castings of complex geometries. Little work has been carried out on cast magnesium alloys using the lost foam process. The article describes the research activities at Oak Ridge National Laboratory and Tennessee Technological University on lost foam casting of magnesium alloys. The work was focused on castings of simple geometries such as plate castings and window castings. The plate castings were designed to investigate the mold filling characteristics of magnesium and aluminum alloys using an infrared camera. The pate castings were then characterized for porosity distribution. The window castings were made to test the castability of the alloys under lost foam conditions. Significant differences between lost foam aluminum casting and lost foam magnesium casting have been observed.

  20. High density tape casting system

    NASA Technical Reports Server (NTRS)

    Collins, Earl R., Jr. (inventor)

    1989-01-01

    A system is provided for casting thin sheets (or tapes) of particles bound together, that are used for oxygen membranes and other applications, which enables the particles to be cast at a high packing density in a tape of uniform thickness. A slurry contains the particles, a binder, and a solvent, and is cast against the inside walls of a rotating chamber. Prior to spraying the slurry against the chamber walls, a solvent is applied to a container. The solvent evaporates to saturate the chamber with solvent vapor. Only then is the slurry cast. As a result, the slurry remains fluid long enough to spread evenly over the casting surface formed by the chamber, and for the slurry particles to become densely packed. Only then is the chamber vented to remove solvent, so the slurry can dry. The major novel feature is applying solvent vapor to a rotating chamber before casting slurry against the chamber walls.

  1. Energy transfer based photoluminescence properties of (Sm3+ + Eu3+):PEO + PVP polymer films for Red luminescent display device applications

    NASA Astrophysics Data System (ADS)

    Naveen Kumar, K.; Vijayalakshmi, L.; Ratnakaram, Y. C.

    2015-07-01

    Eu3+:PEO + PVP, Sm3+:PEO + PVP and co-doped Sm3+ + Eu3+:PEO + PVP polymer films have successfully been synthesized by solution casting method. For these polymer films, their XRD, FTIR and RAMAN spectral profiles were studied systematically. Both absorption and photoluminescence spectra have been assessed by evaluating their optical properties. The Sm3+:PEO + PVP and Eu3+:PEO + PVP polymer film has displayed a reddish-orange and red emissions at 596 nm and 619 nm respectively under an UV lamp. A reddish-orange emission was found for Sm3+:PEO + PVP polymer film at 596 nm (4G5/2 ? 6H7/2) and its lifetime has also been evaluated suitably. Red emission at 619 nm (4G5/2 ? 6H7/2) of Eu3+ has been identified for Eu3+:PEO + PVP polymer film and its lifetime are also evaluated. The photoluminescence efficiency of Eu3+ ion has been enhanced due to the addition of Sm3+ by means of an energy transfer process. The energy transfer mechanism, from Sm3+ to Eu3+ has been clearly established. At 0.1 wt% concentration of Sm3+ ions (sensitizer), the photoluminescence efficiency of the Eu3+ ion (activator) has been significantly enhanced in co-doped sample through energy transfer from Sm3+ to Eu3+ in the polymer matrix. The energy transfer process has been analyzed using lifetime decay dynamics. From the obtained results, these polymer materials could be proposed as potential Red luminescent optical materials.

  2. Intensity tunable infrared broadband absorbers based on VO2 phase transition using planar layered thin films

    NASA Astrophysics Data System (ADS)

    Kocer, Hasan; Butun, Serkan; Palacios, Edgar; Liu, Zizhuo; Tongay, Sefaattin; Fu, Deyi; Wang, Kevin; Wu, Junqiao; Aydin, Koray

    2015-08-01

    Plasmonic and metamaterial based nano/micro-structured materials enable spectrally selective resonant absorption, where the resonant bandwidth and absorption intensity can be engineered by controlling the size and geometry of nanostructures. Here, we demonstrate a simple, lithography-free approach for obtaining a resonant and dynamically tunable broadband absorber based on vanadium dioxide (VO2) phase transition. Using planar layered thin film structures, where top layer is chosen to be an ultrathin (20?nm) VO2 film, we demonstrate broadband IR light absorption tuning (from ~90% to ~30% in measured absorption) over the entire mid-wavelength infrared spectrum. Our numerical and experimental results indicate that the bandwidth of the absorption bands can be controlled by changing the dielectric spacer layer thickness. Broadband tunable absorbers can find applications in absorption filters, thermal emitters, thermophotovoltaics and sensing.

  3. Intensity tunable infrared broadband absorbers based on VO2 phase transition using planar layered thin films

    PubMed Central

    Kocer, Hasan; Butun, Serkan; Palacios, Edgar; Liu, Zizhuo; Tongay, Sefaattin; Fu, Deyi; Wang, Kevin; Wu, Junqiao; Aydin, Koray

    2015-01-01

    Plasmonic and metamaterial based nano/micro-structured materials enable spectrally selective resonant absorption, where the resonant bandwidth and absorption intensity can be engineered by controlling the size and geometry of nanostructures. Here, we demonstrate a simple, lithography-free approach for obtaining a resonant and dynamically tunable broadband absorber based on vanadium dioxide (VO2) phase transition. Using planar layered thin film structures, where top layer is chosen to be an ultrathin (20?nm) VO2 film, we demonstrate broadband IR light absorption tuning (from ~90% to ~30% in measured absorption) over the entire mid-wavelength infrared spectrum. Our numerical and experimental results indicate that the bandwidth of the absorption bands can be controlled by changing the dielectric spacer layer thickness. Broadband tunable absorbers can find applications in absorption filters, thermal emitters, thermophotovoltaics and sensing. PMID:26294085

  4. Nafion Film Based Micro-nanofluidic Device for Concurrent DNA Preconcentration and Separation in Free Solution.

    PubMed

    Song, Hongjun; Wang, Yi; Garson, Charles; Pant, Kapil

    2014-10-01

    This paper presents a Nafion film based micro-nanofluidic device for concurrent DNA preconcentration and separation. The principle of the device is based on the combination of (a) ion concentration polarization phenomenon at the junction of the microchannel and the nanochannels in the Nafion film to form opposing electrophoretic and electroosmotic forces acting on the DNAs, and (b) end-labeled free solution electrophoresis to harness the charge-to-mass ratio for molecular differentiation. The experiments successfully demonstrated concurrent preconcentration and separation of DNA mixture in free solution within 240s, yielding concentration ratios up to 1,150X and separation resolution of 1.85. The effect of applied electric field on the concentration and separation performance was also investigated. The device can be used as a key sample preparation element in conjunction with micro- or nano-fluidic sensors for microTAS functionality. PMID:25346656

  5. Intensity tunable infrared broadband absorbers based on VO2 phase transition using planar layered thin films.

    PubMed

    Kocer, Hasan; Butun, Serkan; Palacios, Edgar; Liu, Zizhuo; Tongay, Sefaattin; Fu, Deyi; Wang, Kevin; Wu, Junqiao; Aydin, Koray

    2015-01-01

    Plasmonic and metamaterial based nano/micro-structured materials enable spectrally selective resonant absorption, where the resonant bandwidth and absorption intensity can be engineered by controlling the size and geometry of nanostructures. Here, we demonstrate a simple, lithography-free approach for obtaining a resonant and dynamically tunable broadband absorber based on vanadium dioxide (VO2) phase transition. Using planar layered thin film structures, where top layer is chosen to be an ultrathin (20?nm) VO2 film, we demonstrate broadband IR light absorption tuning (from ~90% to ~30% in measured absorption) over the entire mid-wavelength infrared spectrum. Our numerical and experimental results indicate that the bandwidth of the absorption bands can be controlled by changing the dielectric spacer layer thickness. Broadband tunable absorbers can find applications in absorption filters, thermal emitters, thermophotovoltaics and sensing. PMID:26294085

  6. Cast dielectric composite linear accelerator

    DOEpatents

    Sanders, David M. (Livermore, CA); Sampayan, Stephen (Manteca, CA); Slenes, Kirk (Albuquerque, NM); Stoller, H. M. (Albuquerque, NM)

    2009-11-10

    A linear accelerator having cast dielectric composite layers integrally formed with conductor electrodes in a solventless fabrication process, with the cast dielectric composite preferably having a nanoparticle filler in an organic polymer such as a thermosetting resin. By incorporating this cast dielectric composite the dielectric constant of critical insulating layers of the transmission lines of the accelerator are increased while simultaneously maintaining high dielectric strengths for the accelerator.

  7. Zinc oxide thin film/nanorods based lossy mode resonance hydrogen sulphide gas sensor

    NASA Astrophysics Data System (ADS)

    Usha, Sruthi P.; Mishra, Satyendra K.; Gupta, Banshi D.

    2015-09-01

    We report a fiber optic hydrogen sulfide gas sensor based on lossy mode resonance utilizing a coating of zinc oxide thin film along with nanorods over the unclad core of the fiber. The sensor is characterized in terms of peak absorbance wavelength determined from the recorded lossy mode resonance spectra for different concentrations of the hydrogen sulfide gas. To achieve the maximum sensitivity of the sensor, the growing period of the nanorods is optimized. It is found that the sensitivity of the sensor depends on the concentration of the gas. Further, the sensor is best suited for low concentrations (less than 60 ppm) of the gas. Experiments are also performed on the probe fabricated with zinc oxide nanorods grown over the unclad portion of the fiber. On comparison, it is found that the probe with layers of zinc oxide thin film and its nanorods is more sensitive than the probe that has layer of nanorods only. This is because of the large active surface area available in the probe fabricated with zinc oxide thin film and its nanorods. In addition, the probe with zinc oxide thin film and its nanorods is highly selective to hydrogen sulfide gas.

  8. Surface segregation in TiO2-based nanocomposite thin films.

    PubMed

    Chakravadhanula, Venkata Sai Kiran; Kübel, Christian; Hrkac, Tomislav; Zaporojtchenko, Vladimir; Strunskus, Thomas; Faupel, Franz; Kienle, Lorenz

    2012-12-14

    The morphology of nanocomposites plays a pivotal role in understanding their functionality and determines their capabilities for applications. The use of nanocomposite coatings requires a study of the size effects on their functional properties. Noble metal nanoparticles are promising candidates for nanocomposite thin film applications due to their antibacterial, plasmonic and photocatalytic properties. In this contribution, the morphology of Ag-TiO(2) and Au-TiO(2) nanocomposite thin films has been investigated experimentally using electron tomography in transmission electron microscopy in combination with UV/vis spectroscopy. Based on the additional 3D information obtained from tomography, we propose a two-step model towards the observed bimodal particle size in these nanocomposite thin films prepared by co-sputtering from two different sources. Furthermore, we show that the optical properties exhibit a well-defined relation with the morphology of the nanocomposite thin films. The present investigations demonstrate the potential of electron tomography for revealing the complex structure and formation processes of functional nanocomposites. PMID:23150221

  9. Potential of kaolin-based particle film barriers for Formosan subterranean termite (Isoptera: Rhinotermitidae) control

    USGS Publications Warehouse

    Wiltz, B.A.; Woodson, W.D.; Puterka, G.J.

    2010-01-01

    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 long no-choice feeding tests, significant mortality occurred only with M96-018-coated wood. When a choice was provided, M96-018 and Surround were consumed at higher rates than untreated wood. Surround WP did not differ from controls in either test. In the tunneling assay termites were given the option of crossing a kaolin-sand mixture to reach an alternate food source. After 3-weeks, rates of 1% and 5% M96-018 provided an effective barrier to Formosan termite tunneling, while termites were not stopped by rates as high as 20% Surround and Surround WP. Dust treatments of all three formulations caused significant increases in mortality within 24 h, with mortality rates ranging from 72.0 - 97.3% within 72 h of treatment. The particle films were most effective when moisture levels were low, suggesting that desiccation was the mechanism for mortality. All particle films showed potential for use in above ground applications while hydrophobic M06-018 has the most potential as a soil barrier to subterranean termites.

  10. Pattern formation in Langmuir-Blodgett films of tricycloquinazoline based discotic liquid crystal molecules

    NASA Astrophysics Data System (ADS)

    Karthik, C.; Manjuladevi, V.; Gupta, R. K.; Kumar, Sandeep

    2014-07-01

    The assembly of molecules on the surface has drawn considerable attention because of its potential to tailor the physicochemical, electronic, and magnetic properties of materials. The structure of aggregates of molecules can be influenced by the molecular interactions and the external parameters like temperature, pressure and ion contents. We have found a stable Langmuir monolayer of amphiphilic tricycloquinazoline based discotic liquid crystal (AmTCQ) molecules at air-water (A-W) interface. The monolayer exhibits gas phase, low density liquid phase and high density liquid phase. The structural evolution in Langmuir-Blodgett (LB) films of the AmTCQ molecules as a function of target surface pressure is studied using an atomic force microscope. We found aggregation of the discotic molecules leading to nucleation sites at a lower surface pressure. With the increasing surface pressure, each nucleation site grows to form a stable triangular structure. The shape and size of the triangular structure remain stable till the target surface pressure for LB films deposition exceeds the equilibrium surface pressure of the AmTCQ molecules. The number of triangles in the film increases with increasing target surface pressure of LB deposition. The target surface pressure of LB deposition acts as a controlling parameter for obtaining desired number of triangular domains in the film.

  11. Storage stability of banana chips in polypropylene based nanocomposite packaging films.

    PubMed

    Manikantan, M R; Sharma, Rajiv; Kasturi, R; Varadharaju, N

    2014-11-01

    In this study, polypropylene (PP) based nanocomposite films of 15 different compositions of nanoclay, compatibilizer and thickness were developed and used for packaging and storage of banana chips. The effect of nanocomposite films on the quality characteristics viz. moisture content (MC), water activity (WA), total color difference(TCD), breaking force (BF), free fatty acid (FFA), peroxide value(PV), total plate count (TPC) and overall acceptability score of banana chips under ambient condition at every 15 days interval were studied for 120 days. All quality parameters of stored banana chips increased whereas overall acceptability scores decreased during storage. The elevation in FFA, BF and TCD of stored banana chips increased with elapse of storage period as well as with increased proportion of both nanoclay and compatibilizer but decreased by reducing the thickness of film. Among all the packaging materials, the WA of banana chips remained lower than 0.60 i.e. critical limit for microbial growth up to 90 days of storage. The PV of banana chips packaged also remained within the safe limit of 25 meq oxygen kg(-1) throughout the storage period. Among all the nanocomposite films, packaging material having 5 % compatibilizer, 2 % nanoclay & 100 ?m thickness (treatment E) and 10 % compatibilizer, 4 % nanoclay & 120 ?m thickness (treatment N) showed better stability of measured quality characteristics of banana chips than any other treatment. PMID:26396292

  12. ?-Amylase sensor based on the degradation of oligosaccharide hydrogel films monitored with a quartz crystal sensor.

    PubMed

    Gibbs, Martin John; Biela, Anna; Krause, Steffi

    2015-05-15

    ?-Amylase hydrolyses starch molecules to produce smaller oligosaccharides and sugars. Amylases are of great importance in biotechnology and find application in fermentation, detergents, food and the paper industry. The measurement of ?-amylase activity in serum and urine has been used in the diagnosis of acute pancreatitis. Salivary amylase has also been shown to be a stress indicator. Sensor coatings suitable for the detection of ?-amylase activity have been developed. Oligosaccharides such as glycogen and amylopectin were spin-coated onto gold coated quartz crystals with a base frequency of 10 MHz. The films were subsequently cross-linked with hexamethylene diisocyanate. Film degradation was monitored with a quartz crystal microbalance (QCM) and electrochemical impedance measurements. The films were shown to be stable in phosphate buffered saline (PBS). Addition of ?-amylase to the solution resulted in the rapid degradation of the films. The maximum rate of degradation was found to be strongly dependent on the amylase activity in the range typically found in serum when diagnosing pancreatitis (0.08-8 U/ml). Sensor responses in serum were found to be very similar to those obtained in buffer indicating the absence of non-specific binding. PMID:25266253

  13. Band gaps by design: Tailoring ZnO based semiconductor alloy films

    NASA Astrophysics Data System (ADS)

    Che, Hui

    This dissertation presents the research on the synthesis of ZnO based ternary semiconductor alloy films with tailored band gaps and the studies in their structural and optical properties. MgxZn1-xO alloys expanded the band gaps from 3.20 eV to deeper UV region of 5.67 eV. While ZnSxO1-x reduced the band gaps into the visible region of 2.9 eV. The alloy films were grown via reactive sputtering deposition, which is a cost effective and environment-friendly technique. An analytical method was developed for accurately determining the band gaps of alloys via transmission spectroscopy. The structural inhomogeneity issues in the Mg xZn1-xO alloys were studied via Selective Resonant Raman Scattering. Urbach energy analysis and Raman spectral line width analysis indicated that structural defects and alloy composition fluctuations in the MgxZn1-xO alloy films are the dominant origins of the localized electronic tail states and the Raman line broadening. While the Raman line broadening due to the anharmonicity of the alloys is not significant. The achievement of ZnSxO1-x alloy films with reduced band gaps paved the way for further research on band gap engineering of ZnO in the visible region.

  14. Microscopic silicon-based lateral high-aspect-ratio structures for thin film conformality analysis

    SciTech Connect

    Gao, Feng; Arpiainen, Sanna; Puurunen, Riikka L.

    2015-01-15

    Film conformality is one of the major drivers for the interest in atomic layer deposition (ALD) processes. This work presents new silicon-based microscopic lateral high-aspect-ratio (LHAR) test structures for the analysis of the conformality of thin films deposited by ALD and by other chemical vapor deposition means. The microscopic LHAR structures consist of a lateral cavity inside silicon with a roof supported by pillars. The cavity length (e.g., 20–5000??m) and cavity height (e.g., 200–1000?nm) can be varied, giving aspect ratios of, e.g., 20:1 to 25?000:1. Film conformality can be analyzed with the microscopic LHAR by several means, as demonstrated for the ALD Al{sub 2}O{sub 3} and TiO{sub 2} processes from Me{sub 3}Al/H{sub 2}O and TiCl{sub 4}/H{sub 2}O. The microscopic LHAR test structures introduced in this work expose a new parameter space for thin film conformality investigations expected to prove useful in the development, tuning and modeling of ALD and other chemical vapor deposition processes.

  15. Pressure-Sensitive Touch Panel Based on Piezoelectric Poly(L-lactic acid) Film

    NASA Astrophysics Data System (ADS)

    Ando, Masamichi; Kawamura, Hideki; Kitada, Hiroaki; Sekimoto, Yasuyuki; Inoue, Takafumi; Tajitsu, Yoshiro

    2013-09-01

    Poly(lactic acid) (PLA) is a widely used biomass-derived polymer. It is chiral because the lactic acid monomer has an asymmetric carbon. If the L-lactide is polymerized, then the PLA polymer is an L-type PLA or poly(L-lactic acid) (PLLA); if the D-lactide in PLA is polymerized, then the polymer is a D-type PLA (PDLA). When these polymers undergo drawing or elongation, they exhibit shear piezoelectricity. PLA films are highly transparent and do not exhibit pyroelectricity because of the lack of intrinsic polarization. Therefore, if a PLLA film is used for a touch panel, which is operated by pressure, there is no spurious signal due to heating from the fingers. This suggests that PLLA films may be suitable for touch panels using pressure detection. We used PLLA as the base film of a projected capacitive touch panel with multiple electrodes, and demonstrated a multitouch gesture screen that was sensitive to pressure applied on the screen. This touch panel technology has potential applications for smart phones and tablet personal computers.

  16. Polymer-Silica nanoparticles composite films as protective coatings for stone-based monuments

    NASA Astrophysics Data System (ADS)

    Manoudis, P.; Papadopoulou, S.; Karapanagiotis, I.; Tsakalof, A.; Zuburtikudis, I.; Panayiotou, C.

    2007-04-01

    The decrease of surface energy of mineral substrates similar to those used in many stone monuments of cultural heritage by the application of protective polymer coatings along with the simultaneous increase of their surface roughness can increase their ability to repel water substantially. In this work, the effect of artificially induced roughness on the water repellency of mineral substrates coated with protective polymer films was investigated. Natural marble samples or home made calcium carbonate blocks were tried as the mineral substrates. The roughness increase was achieved by mineral chemical etching or by creation of nanoscale binary composition film on the substrate surface. PMMA and PFPE were the polymers used, while different-sized silica nanoparticles were employed for the production of the nanocomposite films. Examination of the coated and uncoated surfaces with profilometry and AFM and measurements of water contact angles reveal a pronounced effect of the surface roughness on water repellency. Especially in the case of nanocomposite coatings, the surfaces become super-hydrophobic. This result indicates that the nanoscale binary composition film scheme, which is characterized by its simplicity and low cost, is a suitable candidate for the water protection of stone-based monuments on large scale.

  17. Impedimetric biosensor based on cell-mediated bioimprinted films for bacterial detection.

    PubMed

    Qi, Peng; Wan, Yi; Zhang, Dun

    2013-01-15

    This work presents the synthesis of bacteria-mediated bioimprinted films for selective bacterial detection. Marine pathogen sulfate-reducing bacteria (SRB) were chosen as the template bacteria. Chitosan (CS) doped with reduced graphene sheets (RGSs) was electrodeposited on an indium tin oxide electrode, and the resulting RGSs-CS hybrid film served as a platform for bacterial attachment. The electrodeposition conditions were optimized to obtain RGSs-CS hybrid films with excellent electrochemical performance. A layer of nonconductive CS film was deposited to embed the pathogen, and acetone was used to wash away the bacterial templates. Electrochemical impedance spectroscopy was performed to characterize the stepwise modification process and monitor the SRB population. Faradic impedance measurements revealed that the charge transfer resistance (R(ct)) increased with increased SRB concentration. A linear relationship between ?R(ct) and the logarithm of SRB concentration was obtained within the concentration range of 1.0×10(4)cfum L(-1) to 1.0×10(8)cfum L(-1). The impedimetric sensor showed good selectivity towards SRB based on size and shape. Hence, selectivity for bacterial detection can be improved if the bioimprinting technique is combined with other bio-recognition elements. PMID:22917919

  18. Cathodoluminescence studies of C{sub 60} fullerene-based films and nanostructures

    SciTech Connect

    Nashchekin, A. V. Baryshev, S. V.; Sokolov, R. V.; Usov, O. A.

    2007-08-15

    The objects of investigation in this work are submicron Cm fullerene-based films and fullerene nanostructures fabricated by electron-beam lithography. The set of techniques for studying the fullerenes is extended due to attraction of the spectral cathodoluminescence (CL) to either of the initial fullerene films or submicron net structures with period of about 0.9 {mu}m, wall height 0.6 {mu}m, and width about 0.4 {mu}m.The maxima of the CL spectra of the initial C{sub 60} films are in good agreement with the energy-band structure of the amorphous fullerene film. In turn, the CL spectrum of the fullerene net structures possesses both peculiarities of the fullerene energy-band structure and it clearly exhibits the oscillations of the spectrum with a period as large as 0.08 eV. Such periodical fullerence net structures possess the properties of an optical resonator on the system 'fullerene net (n = 2.3)-air (n = 1).'.

  19. Surface acoustic wave ammonia sensor based on ZnO/SiO2 composite film.

    PubMed

    Wang, Shuang-Yue; Ma, Jin-Yi; Li, Zhi-Jie; Su, H Q; Alkurd, N R; Zhou, Wei-Lie; Wang, Lu; Du, Bo; Tang, Yong-Liang; Ao, Dong-Yi; Zhang, Shou-Chao; Yu, Q K; Zu, Xiao-Tao

    2015-03-21

    A surface acoustic wave (SAW) resonator with ZnO/SiO2 (ZS) composite film was used as an ammonia sensor in this study. ZS composite films were deposited on the surface of SAW devices using the sol-gel method, and were characterized using SEM, AFM, and XRD. The performance of the sensors under ammonia gas was optimized by adjusting the molar ratio of ZnO:SiO2 to 1:1, 1:2 and 1:3, and the sensor with the ratio of ZnO to SiO2 equaling to 1:2 was found to have the best performance. The response of sensor was 1.132 kHz under 10 ppm NH3, which was much higher than that of the sensor based on a pristine ZnO film. Moreover, the sensor has good selectivity, reversibility and stability at room temperature. These can be attributed to the enhanced absorption of ammonia and unique surface reaction on composite films due to the existence of silica. PMID:25528236

  20. Advanced high temperature superconductor film-based process using RABiTS

    SciTech Connect

    Goyal, A.; Hawsey, R.A.; Hack, J.; Moon, D.

    2000-01-01

    The purpose of this Cooperative Research and Development Agreement (CRADA) between Lockheed Martin Energy Research Corporation (Contractor), Managing contractor for Oak Ridge National Laboratory (ORNL) and Midwest Superconductivity, Inc. (MSI) and Westinghouse Science and Electric Company (WEC) was to develop the basis for a commercial process for the manufacturing of superconducting tape based on the RABiTS technology developed at ORNL. The chosen method for deposition of YBCO films on RABiTS was Metal Organic chemical Vapor Deposition (MOCVD).

  1. Lost-Wax Casting in Ancient China: New Discussion on Old Debates

    NASA Astrophysics Data System (ADS)

    Zhou, Weirong; Huang, Wei

    2015-07-01

    The possible use of lost-wax casting in China has long been a matter of controversy. Based on the study of pertinent ancient texts concerning the technical origins of lost-wax casting in China, direct examination of questioned ancient Chinese bronzes as well as definite lost-wax castings from both overseas and China, and modern production of objects using piece-mold casting, the authors point out their own conceptual ideas about ancient lost-wax casting as follows. First, the lost-wax casting technique does not have its earliest origins in ancient China but rather from the Sumerians in Mesopotamia, where it was predominantly used to cast small human and animal figures (statuettes). Next, some essential characteristics of the lost-wax casting technique can be identified from the point of view of a distortable soft starting model. The locally deformed shape of lost-wax castings is found to be variable. Finally, it is improper to consider the ease of extraction from the mold as the criterion for distinguishing lost-wax casting from piece-mold casting. It is therefore incorrect to conclude that the three-dimensional openwork decorations present on Chinese bronzes from the Spring and Autumn Period, and the Warring States Period, are fabricated using lost-wax castings.

  2. Genomic Diversity at Thirteen Short Tandem Repeat Loci in a Substructured Caste Population, Golla, of Southern Andhra Pradesh, India

    E-print Network

    Reddy, B. Mohan; Sun, Guangyun; Luis, Javier Rodriguez; Crawford, Michael H.; Hemam, Natabar Shyam; Deka, Ranjan

    2001-04-01

    , among castes. It is, however, much higher when compared to the average observed for Indian caste and tribal populations, based on classical markers. Genetic distance measures revealed clusters of populations that are consistent with the known...

  3. Bioinspired Design: Magnetic Freeze Casting

    NASA Astrophysics Data System (ADS)

    Porter, Michael Martin

    Nature is the ultimate experimental scientist, having billions of years of evolution to design, test, and adapt a variety of multifunctional systems for a plethora of diverse applications. Next-generation materials that draw inspiration from the structure-property-function relationships of natural biological materials have led to many high-performance structural materials with hybrid, hierarchical architectures that fit form to function. In this dissertation, a novel materials processing method, magnetic freeze casting, is introduced to develop porous scaffolds and hybrid composites with micro-architectures that emulate bone, abalone nacre, and other hard biological materials. This method uses ice as a template to form ceramic-based materials with continuously, interconnected microstructures and magnetic fields to control the alignment of these structures in multiple directions. The resulting materials have anisotropic properties with enhanced mechanical performance that have potential applications as bone implants or lightweight structural composites, among others.

  4. Flexible thin-film battery based on solid-like ionic liquid-polymer electrolyte

    NASA Astrophysics Data System (ADS)

    Li, Qin; Ardebili, Haleh

    2016-01-01

    The development of high-performance flexible batteries is imperative for several contemporary applications including flexible electronics, wearable sensors and implantable medical devices. However, traditional organic liquid-based electrolytes are not ideal for flexible batteries due to their inherent safety and stability issues. In this study, a non-volatile, non-flammable and safe ionic liquid (IL)-based polymer electrolyte film with solid-like feature is fabricated and incorporated in a flexible lithium ion battery. The ionic liquid is 1-Ethyl-3-methylimidazolium dicyanamide (EMIMDCA) and the polymer is composed of poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP). The electrolyte exhibits good thermal stability (i.e. no weight loss up to 300 °C) and relatively high ionic conductivity (6 × 10-4 S cm-1). The flexible thin-film lithium ion battery based on solid-like electrolyte film is encapsulated using a thermal-lamination process and demonstrates excellent electrochemical performance, in both flat and bent configurations.

  5. Gendered-Caste Discrimination, Human Rights Education, and the Enforcement of the Prevention of Atrocities Act in India

    ERIC Educational Resources Information Center

    Kapoor, Dip

    2007-01-01

    Despite the constitutional ban on the practice of untouchability and caste-based discrimination, this article elaborates on a gendered-caste-based discriminatory reality in rural India, the difficulties of enforcing legal remedies, and on related human rights praxis to address gendered-caste atrocities by drawing on the experiences of a Canadian…

  6. Thermoelectric properties of n-type nanocrystalline bismuth-telluride-based thin films deposited by flash evaporation

    NASA Astrophysics Data System (ADS)

    Takashiri, M.; Takiishi, M.; Tanaka, S.; Miyazaki, K.; Tsukamoto, H.

    2007-04-01

    The thermal conductivity of n-type nanocrystalline bismuth-telluride-based thin films (Bi2.0Te2.7Se0.3) is investigated by a differential 3? method at room temperature. The nanocrystalline thin films are grown on a glass substrate by a flash evaporation method, followed by hydrogen annealing at 250 °C. The structure of the thin films is studied by means of atomic force microscopy, x-ray diffraction, and energy-dispersive x-ray spectroscopy. The thin films exhibit an average grain size of 60 nm and a cross-plane thermal conductivity of 0.8 W/m K. The in-plane electrical conductivity and in-plane Seebeck coefficient are also investigated. Assuming that the in-plane thermal conductivity of the thin films is identical to that of the cross-plane direction, the in-plane figure of merit of the thin films is estimated to be ZT =0.7. As compared with a sintered bulk sample with average grain size of 30 ?m and nearly the same composition as the thin films, the nanocrystalline thin films show approximately a 50% reduction in the thermal conductivity, but the electrical conductivity also falls 40%. The reduced thermal and electrical conductivities are attributed to increased carrier trapping and scattering in the nanocrystalline film.

  7. Optically transparent superhydrophobic silica-based films H.M. Shang*, Y. Wang, S.J. Limmer, T.P. Chou, K. Takahashi, G.Z. Cao

    E-print Network

    Cao, Guozhong

    Optically transparent superhydrophobic silica-based films H.M. Shang*, Y. Wang, S.J. Limmer, T superhydrophobic silica-based films were obtained by means of sol­gel processing and self-assembly (SA). Desired and superhydrophobicity are required, in addition to low temperature processing. In addition, such films can be made

  8. Cast Stainless Steel Ferrite and Grain Structure

    SciTech Connect

    Ruud, Clayton O.; Ramuhalli, Pradeep; Meyer, Ryan M.; Mathews, Royce; Diaz, Aaron A.; Anderson, Michael T.

    2012-09-01

    In-service inspection requirements dictate that piping welds in the primary pressure boundary of light-water reactors be subject to a volumetric examination based on the rules contained within the American Society of Mechanical Engineers Boiler and Pressure Vessel Code, Section XI. The purpose of the inspection is the reliable detection and accurate sizing of service-induced degradation and/or material flaws introduced during fabrication. The volumetric inspection is usually carried out using ultrasonic testing (UT) methods. However, the varied metallurgical macrostructures and microstructures of cast austenitic stainless steel piping and fittings, including statically cast stainless steel and centrifugally cast stainless steel (CCSS), introduce significant variations in the propagation and attenuation of ultrasonic energy. These variations complicate interpretation of the UT responses and may compromise the reliability of UT inspection. A review of the literature indicated that a correlation may exist between the microstructure and the delta ferrite content of the casting alloy. This paper discusses the results of a recent study where the goal was to determine if a correlation existed between measured and/or calculated ferrite content and grain structure in CCSS pipe.

  9. Electrophoretic deposited TiO(2) pigment-based back reflectors for thin film solar cells.

    PubMed

    Bills, Braden; Morris, Nathan; Dubey, Mukul; Wang, Qi; Fan, Qi Hua

    2015-02-01

    Highly reflective coatings with strong light scattering effect have many applications in optical components and optoelectronic devices. This work reports titanium dioxide (TiO(2)) pigment-based reflectors that have 2.5 times higher broadband diffuse reflection than commercially produced aluminum or silver based reflectors and result in efficiency enhancements of a single-junction amorphous Si solar cell. Electrophoretic deposition is used to produce pigment-based back reflectors with high pigment density, controllable film thickness and site-specific deposition. Electrical conductivity of the pigment-based back reflectors is improved by creating electrical vias throughout the pigment-based back reflector by making holes using an electrical discharge / dielectric breakdown approach followed by a second electrophoretic deposition of conductive nanoparticles into the holes. While previous studies have demonstrated the use of pigment-based back reflectors, for example white paint, on glass superstrate configured thin film Si solar cells, this work presents a scheme for producing pigment-based reflectors on complex shape and flexible substrates. Mechanical durability and scalability are demonstrated on a continuous electrophoretic deposition roll-to-roll system which has flexible metal substrate capability of 4 inch wide and 300 feet long. PMID:25836255

  10. Casting Equipment. Casting and Angling Skills Series. Instructor Manual.

    ERIC Educational Resources Information Center

    Staton, Robert D., Jr.

    Part of a series of self-contained instructional units designed by the Missouri Department of Conservation to teach Missourians how to use outdoor resources wisely and skillfully, the instructor manual, the first in the casting and angling series, is intended both as a reference book on casting equipment and as an introduction to the sport.…

  11. Materials-based control of ultrafast relaxation in ferromagnetic thin films

    NASA Astrophysics Data System (ADS)

    Cheng, Lili

    As data rates in magnetic information storage approach 1GHz and above, strategies to control the magnetization dynamics in films become a more pressing need. Materials-based techniques to control relaxation can offer a straightforward implementation for this purpose. Strategies to both increase and decrease the damping constant in ferromagnetic thin films are described in this thesis. By doping rare earth elements, both damping constant and precessional frequency of Ni81Fe19 (Permalloy) can be widely tuned. Sm, Tb, Dy, and Ho all contribute to damping in Ni81Fe19, among which the contribution of relaxation rate from Ho (1.9GHz/%) is the most, which is four times of that from Tb. The increased damping correlates well to the magnetic states of the rare earths. One element, Eu, does not contribute to damping, but it boosts the precessional frequency over a large range (>500 MHz) in Ni 81Fe19. Fe has the lowest damping constant of all elemental ferromagnets. We demonstrate that by doping V into pure Fe, the damping constant can be further reduced. High quality MgO(100)/Fe1-xV x epitaxial thin films are deposited by UHV deposition, with the 35 GHz FMR linewidth (42 Oe) of MgO(100)/Fe film even smaller than the narrowest linewidth of Fe ever reported. As V is doped in, Gilbert damping G decreases. The minimum G value observed is only 14% of that of undoped Fe film, and is even only 34% of the lowest G value ever reported on metallic ferromagnets. The decrease in the Gilbert damping G is closely related to the reduced magnetic anisotropy in the system. The results of this thesis will help advance the understanding of the damping mechanisms in ferromagnets and provide more freedom in engineering the GHz response of the magnetoelectronic devices.

  12. Self-assembled multiwalled carbon nanotube films assisted by ureidopyrimidinone-based multiple hydrogen bonds.

    PubMed

    Wang, Sumin; Guo, Hao; Wang, Xiaomin; Wang, Qiguan; Li, Jinhua; Wang, Xinhai

    2014-11-01

    Self-assembled functionalized multiwalled carbon nanotube (MWNT) films were successfully constructed, linked by a kind of strong binding strength from the self-complementary hydrogen-bonding array of ureidopyrimidinone-based modules (UPM) attached. Employing the feasible reaction of isocyanate containing ureidopyrimidinone with amine modified MWNTs, the UPMs composed of ureidopyrimidinone and ureido were attached to MWNTs with the content as low as 0.6 mmol/g MWNTs. Upon multiple hydrogen-bonding interactions from incorporation of the AADD (A, hydrogen-bonding acceptor; D, hydrogen-bonding donor) quadruple hydrogen bonds of ureidopyrimidinone and the double hydrogen bonds of ureido group, UPM functionalized MWNTs (MWNT-UPM) can be well dispersed in the polar solvent of N,N-dimethylformamide (DMF), while they tend to self-assemble to give a self-supported film in the apolar solvent of CHCl3. In addition, by using the multiple hydrogen-bonding interactions as the driving force, the layer-by-layer (LBL) MWNT-UPM films with high coverage on solid slides can be processed. Because of the self-association of MWNT-UPM in apolar solvent, it was found that the LBL assembly of MWNT-UPM was more favorable in the polar solvent of DMF than in the apolar solvent of CHCl3. Moreover, the hydrogen-bonding linked MWNT-UPM films showed good stability upon soaking in different solvents. Furthermore, the as-prepared LBL films showed electrochemical active behaviors, exhibiting a remarkable catalytic effect on the reduction of nifedipine. PMID:25296167

  13. A Comparison between Shear Bond Strength of VMK Master Porcelain with Three Base-metal Alloys (Ni-cr-T3, VeraBond, Super Cast) and One Noble Alloy (X-33) in Metal-ceramic Restorations

    PubMed Central

    Ahmadzadeh, A; Neshati, A; Mousavi, N; Epakchi, S; Dabaghi Tabriz, F; Sarbazi, AH

    2013-01-01

    Statement of Problem: The increase in the use of metal-ceramic restorations and a high prevalence of porcelain chipping entails introducing an alloy which is more compatible with porcelain and causes a stronger bond between the two. This study is to compare shear bond strength of three base-metal alloys and one noble alloy with the commonly used VMK Master Porcelain. Materials and Method: Three different groups of base-metal alloys (Ni-cr-T3, Super Cast, and VeraBond) and one group of noble alloy (X-33) were selected. Each group consisted of 15 alloy samples. All groups went through the casting process and change from wax pattern into metal disks. The VMK Master Porcelain was then fired on each group. All the specimens were put in the UTM; a shear force was loaded until a fracture occurred and the fracture force was consequently recorded. The data were analyzed by SPSS Version 16 and One-Way ANOVA was run to compare the shear strength between the groups. Furthermore, the groups were compared two-by-two by adopting Tukey test. Results: The findings of this study revealed shear bond strength of Ni-Cr-T3 alloy was higher than the three other alloys (94 MPa or 330 N). Super Cast alloy had the second greatest shear bond strength (80. 87Mpa or 283.87 N). Both VeraBond (69.66 MPa or 245 N) and x-33 alloys (66.53 MPa or 234 N) took the third place. Conclusion: Ni-Cr-T3 with VMK Master Porcelain has the greatest shear bond strength. Therefore, employment of this low-cost alloy is recommended in metal-ceramic restorations. PMID:24724144

  14. Poly(gamma-benzyl alpha, L glutamic acid)-based piezoelectric films & microfibers

    NASA Astrophysics Data System (ADS)

    Farrar, Dawnielle

    Piezoelectric materials in use today are often made of ceramic crystals. Although most ceramics offer high piezoelectricity, they are brittle and require expensive processing conditions. For applications where flexibility is required in addition to high piezoelectric activity, polymers are a very attractive alternative. An ideal piezoelectric material is the one where the piezoelectricity and mechanical properties can be altered individually so that the mechanical stiffness of the material can be varied for particular applications or tuned to match that of the surroundings (e.g. air or water) for increased transduction sensitivity. This is typically achieved by production of composite materials containing piezoelectric and matrix components. Here, we present new composite films and microfibers based on the biopolymer, poly(gamma-benzyl alpha,L-glutamate) (PBLG) and discuss their fabrication and piezoelectric properties. Fabrication of PBLG films and fibers was made possible by PBLG's extreme solubility in organic solvents. By simultaneous poling and curing of PBLG/methylmethacrylate (MMA) mixture solutions via corona charging, we fabricated a flexible composite film [80% PBLG and 20% Poly(methylmethacrylate) (PMMA)] with approximately 20% of the PBLG molecules oriented normal to the film surface. This PBLG film exhibited high piezoelectricity (d33 = 20 pC/N), and its Young's modulus was 1 GPa. However, significant amount of MMA evaporated during the corona charging process that precluded the fabrication of films with pre-determined PBLG-PMMA composition. We also fabricated thick composite disk (thickness: 3 cm) by breakdown charging and thermal polymerization of PBLG/PMMA mixture solution, a process that does not allow MMA evaporation. The composite disk exhibited low piezoelectricity (d33 ˜ 3 pC/N) due to low PBLG content (< 30%); however, its mechanical characteristics were similar to those of PMMA, indicating that the piezoelectricity and mechanical strength are independently related to the two polymer components of the composite disk. By electrospinning PBLG/dichloromethane (DCM) solutions under potentials of -(12˜15) kV, we produced piezoelectric microfibers (diameter: 100 nm) with nearly all of the PBLG dipoles oriented along the fiber axis, evidenced by x-ray diffraction. The PBLG fibers showed high piezoelectricity (d 33 = 32 pC/N), and an elastic modulus of 570 MPa. Both the piezoelectric film and fiber systems can be fabricated directly from solution in a mould or on a substrate. Due to the versatility in the fabrication process and the high piezoelectricity, these materials show great promise as transducer materials for loud speakers, microphones, and/or energy harvesting devices.

  15. Solution-based deposition of ceramic thin films for electronic applications

    NASA Astrophysics Data System (ADS)

    Yu, Shijun

    With the requirement of a low-temperature process which is compatible with flexible electronics, solution-based processes for ceramic thin films have received substantial attention in recent years. In this study, two different variations of solution processing were explored. Liquid phase deposition (LPD) was used to prepare for F-doped SiO2 and F-doped SnO2, and hydrothermal processing was used to prepare ZnO thin films consisting of vertically aligned nanorods. F-doped SiO2 thin films were developed from supersaturated hydrofluorosilicic acid (H2SiF6) solution with the addition of boric acid (H3BO3). The microstructure dependence of LPD SiO2 films on solution parameters and deposition temperature was systematically investigated. The dielectric constant is lower than that of thermal SiO2, resulting from the fluorine doping. The remarkably low dielectric constant, relatively low leakage current and fairly high elastic modulus make these low temperature processed LPD SiO2 films very promising for an interlayer dielectric for flexible substrates. Using the same LPD method, smooth SnO2 films were deposited on both silicon and glass substrates at 60 ºC through supersaturated solutions of SnF 2 with a concentration range from 10 mM to 40 mM. They consist of nanoscale crystallites and the degree of crystallinity increase with annealing temperature. A hydrothermal process was employed to deposit ZnO films for energy harvesting devices. A polymer mask was patterned on top of a zinc acetate seed layer to generate a regular array of open holes (200 nm in diameter) using a nanoimprint. Vertically aligned ZnO nanorod arrays were grown on these open holes that expose the seed layer. The morphology and microstrucutre of the nanorods were studied according to chemical composition of the solution. Equimolar reduce of the concentration of ZnAc and HMTA results in decrease in nanorod diameter, as well as in length. The nanorods become thinner and slightly better aligned with decreased HMTA concentration, and thicker rods and faster deposition rate were observed for increased HMTA concentration. Temperature plays a critical role and nanorods gown at 90 ºC seems to have better alignment than those grown at 80 ºC. More process optimization will be needed to achieve the controlled growth of nanorod structures.

  16. Thin-film transistors based on p-type Cu{sub 2}O thin films produced at room temperature

    SciTech Connect

    Fortunato, Elvira; Figueiredo, Vitor; Barquinha, Pedro; Elamurugu, Elangovan; Goncalves, Goncalo; Martins, Rodrigo; Park, Sang-Hee Ko; Hwang, Chi-Sun

    2010-05-10

    Copper oxide (Cu{sub 2}O) thin films were used to produce bottom gate p-type transparent thin-film transistors (TFTs). Cu{sub 2}O was deposited by reactive rf magnetron sputtering at room temperature and the films exhibit a polycrystalline structure with a strongest orientation along (111) plane. The TFTs exhibit improved electrical performance such as a field-effect mobility of 3.9 cm{sup 2}/V s and an on/off ratio of 2x10{sup 2}.

  17. 14 CFR 23.621 - Casting factors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  18. 14 CFR 29.621 - Casting factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  19. 14 CFR 23.621 - Casting factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  20. 14 CFR 25.621 - Casting factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  1. 14 CFR 27.621 - Casting factors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  2. 14 CFR 27.621 - Casting factors.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  3. 14 CFR 25.621 - Casting factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  4. 14 CFR 29.621 - Casting factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  5. 14 CFR 23.621 - Casting factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  6. 14 CFR 25.621 - Casting factors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  7. 14 CFR 25.621 - Casting factors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  8. 14 CFR 29.621 - Casting factors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  9. 14 CFR 23.621 - Casting factors.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  10. 14 CFR 27.621 - Casting factors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  11. 14 CFR 29.621 - Casting factors.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  12. 14 CFR 27.621 - Casting factors.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ...the method of inspection used; and (2) Need not be used with respect to the bearing surfaces of a part whose bearing factor is larger than the applicable casting factor. (c) Critical castings. For each casting whose failure...

  13. When Your Child Needs a Cast

    MedlinePLUS

    ... hard bandage that's usually made of material like fiberglass or plaster. Casts keep bones in place while ... water. Plaster of Paris casts are heavier than fiberglass casts and don't hold up as well ...

  14. Comparison of CF4 and SF6 based plasmas for ECR etching of isotopically enriched 10Boron films

    SciTech Connect

    Voss, L F; Reinhardt, C E; Graff, R T; Conway, A M; Nikolic, R J; Deo, N; Cheung, C L

    2009-02-23

    Isotopically enriched {sup 10}boron films have been successfully etched in an ECR etching tool using CF{sub 4} and SF{sub 6} based plasmas. Comparisons between the two are made with regards to etch rate, selectivity to the underlying Si device structure, and morphology of the {sup 10}boron post-etching. The present film etching development is expected to be critical for the fabrication of next generation thermal neutron solid state detectors based on {sup 10}boron.

  15. 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

    ...the manufacture of sheet film, 35 mm motion pictures, aerial and still photography into the 1950s...nitrocellulose film materials (e.g., 35mm motion picture film and large series of still pictures) from records storage areas....

  16. 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

    ...the manufacture of sheet film, 35 mm motion pictures, aerial and still photography into the 1950s...nitrocellulose film materials (e.g., 35mm motion picture film and large series of still pictures) from records storage areas....

  17. 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

    ...the manufacture of sheet film, 35 mm motion pictures, aerial and still photography into the 1950s...nitrocellulose film materials (e.g., 35mm motion picture film and large series of still pictures) from records storage areas....

  18. 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

    ...the manufacture of sheet film, 35 mm motion pictures, aerial and still photography into the 1950s...nitrocellulose film materials (e.g., 35mm motion picture film and large series of still pictures) from records storage areas....

  19. Gas sensing studies of pulsed laser deposition deposited WO3 nanorod based thin films.

    PubMed

    Ahmad, Muhammad Z; Kang, Joonhee; Zoolfakar, Ahmad S; Sadek, Abu Z; Wlodarski, Wojtek

    2013-12-01

    WO3 nanorod based thin films were deposited via pulsed laser deposition onto quartz conductometric transducers with pre-patterned gold interdigitated transducers (IDT) employing the shortest wavelength (193 nm) ArF excimer laser. Micro-characterization techniques such as scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to study surface morphology and crystal structure. It was observed that the fabricated films showed nanocolumnar features perpendicular to the surface. The measured sizes of the nanorods were found to be approximately -50 nm in diameter. The high resolution TEM (HRTEM) image of the nanorods based WO3 showed the WO3 lattice spacing of 3.79 angstroms corresponding to the (020) plane of monoclinic WO3. Gas sensing characterizations of the developed sensors were tested towards hydrogen and ethanol at temperatures between room and 400 degrees C. The sensor exhibited high response towards H2 and ethanol at operating temperatures of 170 and 400 degrees C, respectively. The excellent sensing characteristics of WO3 films towards ethanol and H2 at low concentrations offer great potential for low cost and stable gas sensing. PMID:24266229

  20. Unipolar sequential circuits based on individual-carbon-nanotube transistors and thin-film carbon resistors.

    PubMed

    Ryu, Hyeyeon; Kälblein, Daniel; Schmidt, Oliver G; Klauk, Hagen

    2011-09-27

    A fabrication process for the monolithic integration of field-effect transistors based on individual carbon nanotubes and load resistors based on vacuum-evaporated carbon films into fast unipolar logic circuits on glass substrates is reported for the first time. The individual-carbon-nanotube transistors operate with relatively small gate-source and drain-source voltages of 1 V and combine large transconductance (up to 6 ?S), large ON/OFF ratio (>10(4)), and short switching delay time constants (12 ns). The thin-film carbon load resistors provide linear current-voltage characteristics and resistances between 300 k? and 100 M?, depending on the layout of the resistors and the thickness of the vacuum-evaporated carbon films. Various combinational circuits (NAND, NOR, AND, OR gates) as well as a sequential circuit ( ?S ?R NAND latch) have been fabricated and characterized. Although these unipolar circuits cannot compete with optimized complementary circuits in terms of integration density and static power consumption, they offer the possibility of realizing air-stable, low-voltage integrated circuits with promising static and dynamic performance on unconventional substrates for large-area electronics applications, such as displays or sensors. PMID:21870841

  1. Graphene oxide/carbon nanoparticle thin film based IR detector: Surface properties and device characterization

    NASA Astrophysics Data System (ADS)

    Chowdhury, Farzana Aktar; Hossain, Mohammad Abul; Uchida, Koji; Tamura, Takahiro; Sugawa, Kosuke; Mochida, Tomoaki; Otsuki, Joe; Mohiuddin, Tariq; Boby, Monny Akter; Alam, Mohammad Sahabul

    2015-10-01

    This work deals with the synthesis, characterization, and application of carbon nanoparticles (CNP) adorned graphene oxide (GO) nanocomposite materials. Here we mainly focus on an emerging topic in modern research field presenting GO-CNP nanocomposite as a infrared (IR) radiation detector device. GO-CNP thin film devices were fabricated from liquid phase at ambient condition where no modifying treatments were necessary. It works with no cooling treatment and also for stationary objects. A sharp response of human body IR radiation was detected with time constants of 3 and 36 sec and radiation responsivity was 3 mAW-1. The current also rises for quite a long time before saturation. This work discusses state-of-the-art material developing technique based on near-infrared photon absorption and their use in field deployable instrument for real-world applications. GO-CNP-based thin solid composite films also offer its potentiality to be utilized as p-type absorber material in thin film solar cell, as well.

  2. EBT GAFCHROMIC(TM) film dosimetry in compensator-based intensity modulated radiation therapy.

    PubMed

    Vaezzadeh, Seyedali; Allahverdi, Mahmoud; Nedaie, Hasan A; Ay, Mohammadreza; Shirazi, Alireza; Yarahmadi, Mehran

    2013-01-01

    The electron benefit transfer (EBT) GAFCHROMIC films possess a number of features making them appropriate for high-quality dosimetry in intensity-modulated radiation therapy (IMRT). Compensators to deliver IMRT are known to change the beam-energy spectrum as well as to produce scattered photons and to contaminate electrons; therefore, the accuracy and validity of EBT-film dosimetry in compensator-based IMRT should be investigated. Percentage-depth doses and lateral-beam profiles were measured using EBT films in perpendicular orientation with respect to 6 and 18 MV photon beam energies for: (1) different thicknesses of cerrobend slab (open, 1.0, 2.0, 4.0, and 6.0 cm), field sizes (5×5, 10×10, and 20×20 cm(2)), and measurement depths (Dmax, 5.0 and 10.0 cm); and (2) step-wedged compensator in a solid phantom. To verify results, same measurements were implemented using a 0.125 cm(3) ionization chamber in a water phantom and also in Monte Carlo simulations using the Monte Carlo N-particle radiation transport computer code. The mean energy of photons was increased due to beam hardening in comparison with open fields at both 6 and 18 MV energies. For a 20×20 cm(2) field size of a 6 MV photon beam and a 6.0 cm thick block, the surface dose decreased by about 12% and percentage-depth doses increased up to 3% at 30.0 cm depth, due to the beam-hardening effect induced by the block. In contrast, at 18 MV, the surface dose increased by about 8% and depth dose reduced by 3% at 30.0 cm depth. The penumbral widths (80% to 20%) increase with block thickness, field size, and beam energy. The EBT film results were in good agreement with the ionization chamber dose profiles and Monte Carlo N-particle radiation transport computer code simulation behind the step-wedged compensator. Also, there was a good agreement between the EBT-film and the treatment-planning results on the anthropomorphic phantom. The EBT films can be accurately used as a 2D dosimeter for dose verification and quality assurance of compensator-based C-IMRT. PMID:23290715

  3. EBT GAFCHROMIC{sup TM} film dosimetry in compensator-based intensity modulated radiation therapy

    SciTech Connect

    Vaezzadeh, Seyedali; Allahverdi, Mahmoud; Nedaie, Hasan A.; Ay, Mohammadreza; Shirazi, Alireza; Yarahmadi, Mehran

    2013-07-01

    The electron benefit transfer (EBT) GAFCHROMIC films possess a number of features making them appropriate for high-quality dosimetry in intensity-modulated radiation therapy (IMRT). Compensators to deliver IMRT are known to change the beam-energy spectrum as well as to produce scattered photons and to contaminate electrons; therefore, the accuracy and validity of EBT-film dosimetry in compensator-based IMRT should be investigated. Percentage-depth doses and lateral-beam profiles were measured using EBT films in perpendicular orientation with respect to 6 and 18 MV photon beam energies for: (1) different thicknesses of cerrobend slab (open, 1.0, 2.0, 4.0, and 6.0 cm), field sizes (5×5, 10×10, and 20×20 cm{sup 2}), and measurement depths (D{sub max}, 5.0 and 10.0 cm); and (2) step-wedged compensator in a solid phantom. To verify results, same measurements were implemented using a 0.125 cm{sup 3} ionization chamber in a water phantom and also in Monte Carlo simulations using the Monte Carlo N-particle radiation transport computer code. The mean energy of photons was increased due to beam hardening in comparison with open fields at both 6 and 18 MV energies. For a 20×20 cm{sup 2} field size of a 6 MV photon beam and a 6.0 cm thick block, the surface dose decreased by about 12% and percentage-depth doses increased up to 3% at 30.0 cm depth, due to the beam-hardening effect induced by the block. In contrast, at 18 MV, the surface dose increased by about 8% and depth dose reduced by 3% at 30.0 cm depth. The penumbral widths (80% to 20%) increase with block thickness, field size, and beam energy. The EBT film results were in good agreement with the ionization chamber dose profiles and Monte Carlo N-particle radiation transport computer code simulation behind the step-wedged compensator. Also, there was a good agreement between the EBT-film and the treatment-planning results on the anthropomorphic phantom. The EBT films can be accurately used as a 2D dosimeter for dose verification and quality assurance of compensator-based C-IMRT.

  4. Dithienocoronenediimide-based copolymers as novel ambipolar semiconductors for organic thin-film transistors.

    PubMed

    Usta, Hakan; Newman, Christopher; Chen, Zhihua; Facchetti, Antonio

    2012-07-17

    A new class of ambipolar donor-acceptor ?-conjugated polymers based on a dithienocoronenediimide core is presented. Solution-processed top-gate/bottom-contact thin film transistors (TFTs) exhibit electron and hole mobilities of up to 0.30 cm(2)/V·s and 0.04 cm(2)/V·s, respectively, which are the highest reported to date for an ambipolar polymer in ambient conditions. The polymers presented here are the first examples of coronenediimide-based semiconductors showing high organic TFT performances. PMID:22689261

  5. Developing a visual style for computer animations based on film directing techniques 

    E-print Network

    Singler, Sandra

    2000-01-01

    -- traditional film. Within traditional film, the position that provides numerous parallels to the computer animation student is that of the director. Information describing how a director creates a visually compelling film can prove useful to the student when...

  6. High-frequency surface acoustic wave device based on thin-film piezoelectric interdigital transducers

    SciTech Connect

    Sarin Kumar, A.K.; Paruch, P.; Triscone, J.-M.; Daniau, W.; Ballandras, S.; Pellegrino, L.; Marre, D.; Tybell, T.

    2004-09-06

    Using high-quality epitaxial c-axis Pb(Zr{sub 0.2}Ti{sub 0.8})O{sub 3} films grown by off-axis magnetron sputtering onto metallic (001) Nb-doped SrTiO{sub 3} substrates, a nonconventional thin-film surface acoustic wave device based on periodic piezoelectric transducers was realized. The piezoelectric transducers consist of a series of ferroelectric domains with alternating polarization states. The artificial modification of the ferroelectric domain structure is performed by using an atomic force microscope tip as a source of electric field, allowing local switching of the polarization. Devices with 1.2 and 0.8 {mu}m wavelength, defined by the modulation period of the polarization, and corresponding to central frequencies in the range 1.50-3.50 GHz have been realized and tested.

  7. Microstructural evaluation of NiTi-based films deposited by magnetron sputtering

    SciTech Connect

    Cr?ciunescu, Corneliu M. Mitelea, Ion Bud?u, Victor; Ercu?a, Aurel

    2014-11-24

    Shape memory alloy films belonging to the NiTi-based systems were deposited on heated and unheated substrates, by magnetron sputtering in a custom made system, and their structure and composition was analyzed using electron microscopy. Several substrates were used for the depositions: glass, Cu-Zn-Al, Cu-Al-Ni and Ti-NiCu shape memory alloy ribbons and kapton. The composition of the Ti-Ni-Cu films showed limited differences, compared to the one of the target and the microstructure for the DC magnetron sputtering revealed crystallized structure with features determined on peel off samples from a Si wafer. Both inter and transcrystalline fractures were observed and related to the interfacial stress developed on cooling from deposition temperature.

  8. High performance of a solid-state flexible asymmetric supercapacitor based on graphene films

    NASA Astrophysics Data System (ADS)

    Choi, Bong Gill; Chang, Sung-Jin; Kang, Hyun-Wook; Park, Chan Pil; Kim, Hae Jin; Hong, Won Hi; Lee, Sanggap; Huh, Yun Suk

    2012-07-01

    Solid-state flexible energy storage devices hold the key to realizing portable and flexible electronic devices. Achieving fully flexible energy storage devices requires that all of the essential components (i.e., electrodes, separator, and electrolyte) with specific electrochemical and interfacial properties are integrated into a single solid-state and mechanically flexible unit. In this study, we describe the fabrication of solid-state flexible asymmetric supercapacitors based on an ionic liquid functionalized-chemically modified graphene (IL-CMG) film (as the negative electrode) and a hydrous RuO2-IL-CMG composite film (as the positive electrode), separated with polyvinyl alcohol-H2SO4 electrolyte. The highly ordered macroscopic layer structures of these films arising through direct flow self-assembly make them simultaneously excellent electrical conductors and mechanical supports, allowing them to serve as flexible electrodes and current collectors in supercapacitor devices. Our asymmetric supercapacitors have been optimized with a maximum cell voltage up to 1.8 V and deliver a high energy density (19.7 W h kg-1) and power density (6.8 kW g-1), higher than those of symmetric supercapacitors based on IL-CMG films. They can operate even under an extremely high rate of 10 A g-1 with 79.4% retention of specific capacitance. Their superior flexibility and cycling stability are evident in their good performance stability over 2000 cycles under harsh mechanical conditions including twisted and bent states. These solid-state flexible asymmetric supercapacitors with their simple cell configuration could offer new design and fabrication opportunities for flexible energy storage devices that can combine high energy and power densities, high rate capability, and long-term cycling stability.Solid-state flexible energy storage devices hold the key to realizing portable and flexible electronic devices. Achieving fully flexible energy storage devices requires that all of the essential components (i.e., electrodes, separator, and electrolyte) with specific electrochemical and interfacial properties are integrated into a single solid-state and mechanically flexible unit. In this study, we describe the fabrication of solid-state flexible asymmetric supercapacitors based on an ionic liquid functionalized-chemically modified graphene (IL-CMG) film (as the negative electrode) and a hydrous RuO2-IL-CMG composite film (as the positive electrode), separated with polyvinyl alcohol-H2SO4 electrolyte. The highly ordered macroscopic layer structures of these films arising through direct flow self-assembly make them simultaneously excellent electrical conductors and mechanical supports, allowing them to serve as flexible electrodes and current collectors in supercapacitor devices. Our asymmetric supercapacitors have been optimized with a maximum cell voltage up to 1.8 V and deliver a high energy density (19.7 W h kg-1) and power density (6.8 kW g-1), higher than those of symmetric supercapacitors based on IL-CMG films. They can operate even under an extremely high rate of 10 A g-1 with 79.4% retention of specific capacitance. Their superior flexibility and cycling stability are evident in their good performance stability over 2000 cycles under harsh mechanical conditions including twisted and bent states. These solid-state flexible asymmetric supercapacitors with their simple cell configuration could offer new design and fabrication opportunities for flexible energy storage devices that can combine high energy and power densities, high rate capability, and long-term cycling stability. Electronic supplementary information (ESI) available: Photograph and AFM images, XPS spectra, XRD patterns, TGA curves, and evaluated values of energy and power densities are shown in the ESI. See DOI: 10.1039/c2nr30991b

  9. Recent progress in perpendicularly magnetized Mn-based binary alloy films

    NASA Astrophysics Data System (ADS)

    Zhu, Li-Jun; Nie, Shuai-Hua; Zhao, Jian-Hua

    2013-11-01

    In this article, we review the recent progress in growth, structural characterizations, magnetic properties, and related spintronic devices of tetragonal MnxGa and MnxAl thin films with perpendicular magnetic anisotropy. First, we present a brief introduction to the demands for perpendicularly magnetized materials in spintronics, magnetic recording, and permanent magnets applications, and the most promising candidates of tetragonal MnxGa and MnxAl with strong perpendicular magnetic anisotropy. Then, we focus on the recent progress of perpendicularly magnetized MnxGa and MnxAl respectively, including their lattice structures, bulk synthesis, epitaxial growth, structural characterizations, magnetic and other spin-dependent properties, and spintronic devices like magnetic tunneling junctions, spin valves, and spin injectors into semiconductors. Finally, we give a summary and a perspective of these perpendicularly magnetized Mn-based binary alloy films for future applications.

  10. Planar Zeolite Film-Based Potentiometric Gas Sensors Manufactured by a Combined Thick-Film and Electroplating Technique

    PubMed Central

    Marr, Isabella; Reiß, Sebastian; Hagen, Gunter; Moos, Ralf

    2011-01-01

    Zeolites are promising materials in the field of gas sensors. In this technology-oriented paper, a planar setup for potentiometric hydrocarbon and hydrogen gas sensors using zeolites as ionic sodium conductors is presented, in which the Pt-loaded Na-ZSM-5 zeolite is applied using a thick-film technique between two interdigitated gold electrodes and one of them is selectively covered for the first time by an electroplated chromium oxide film. The influence of the sensor temperature, the type of hydrocarbons, the zeolite film thickness, and the chromium oxide film thickness is investigated. The influence of the zeolite on the sensor response is briefly discussed in the light of studies dealing with zeolites as selectivity-enhancing cover layers. PMID:22164042

  11. Optoelectronic scalable substrates based on film/Z-connection and its application to film optical link module (FOLM)

    NASA Astrophysics Data System (ADS)

    Yoshimura, Tetsuzo; Roman, James; Takahashi, Yasuhito; Lee, Michael; Chou, Bill; Beilin, Solomon I.; Wang, Wen-Chou V.; Inao, Masaaki

    2000-04-01

    We propose a new concept of optoelectronic (OE) interconnect hardware 'OE Scalable Substrate (OE-SS)' and 'Film Optical Link Module (FOLM)', which have potentiality to remove optics excess. The structure is as follows: OE-films, in which waveguides, thin-film OE devices, LSIs, capacitor chips etc. are integrated with via/pad/electrode, are stacked by electrical joints (Z-connections). This gives rise to standardized-interface capability and scalability. Using one basic technology 'film/Z-connection', all levels of interconnection will be achieved, including massive parallel optical link, inter-board optical connect, and 3D- stack-OE-MCM. We prose a new process 'Device Integration with Self-Organizing Transfer', which is essential for low- cost OE-SS and FOLM, especially for WDM applications.

  12. Controllable film densification and interface flatness for high-performance amorphous indium oxide based thin film transistors

    SciTech Connect

    Ou-Yang, Wei E-mail: TSUKAGOSHI.Kazuhito@nims.go.jp; Mitoma, Nobuhiko; Kizu, Takio; Gao, Xu; Lin, Meng-Fang; Tsukagoshi, Kazuhito E-mail: TSUKAGOSHI.Kazuhito@nims.go.jp; Nabatame, Toshihide

    2014-10-20

    To avoid the problem of air sensitive and wet-etched Zn and/or Ga contained amorphous oxide transistors, we propose an alternative amorphous semiconductor of indium silicon tungsten oxide as the channel material for thin film transistors. In this study, we employ the material to reveal the relation between the active thin film and the transistor performance with aid of x-ray reflectivity study. By adjusting the pre-annealing temperature, we find that the film densification and interface flatness between the film and gate insulator are crucial for achieving controllable high-performance transistors. The material and findings in the study are believed helpful for realizing controllable high-performance stable transistors.

  13. Prototype casting fabrication by stereolithography

    SciTech Connect

    Cromwell, W.E.

    1992-03-01

    The evolution of the new technology of producing CAD models by ultraviolet solidification of resin materials (``STEREOLITHOGRAPHY``) continues to progress. The potential application area of rigid fabrication of prototype investment castings is becoming more feasible as we continue to successfully yield experimental castings by the ``SHELL`` processing method. This supplemental (to 11/90 publication) report briefly reviews the original project objectives, activities related to these objectives since November 1990, and progress made through December 1991. We discuss several new case studies involving new resin materials (and other materials) tested along with investment casting processing results. The most recent success, the processing of the highly complex ``C`` HOUSING design by the ``shell`` mold process in both aluminum and steel, will be discussed. This is considered a major breakthrough toward establishing this new technology as a viable approach to the rapid development of prototype investment castings, employing the most common aerospace (precision) cast process. Our future planning calls for expanding the study to help the investment casting industry in refining related processing techniques and to continue our evaluation of new resins suitable for the casting process. Present project planning calls for the completion of this study by the third quarter FY93 or sooner. We believe that with the continued excellent cooperation of our casting supplier study team and an accelerated effort by resin materials producers to further refine related materials, we can achieve all objectives during the planned time frame.

  14. Prototype casting fabrication by stereolithography

    SciTech Connect

    Cromwell, W.E.

    1992-03-01

    The evolution of the new technology of producing CAD models by ultraviolet solidification of resin materials ( STEREOLITHOGRAPHY'') continues to progress. The potential application area of rigid fabrication of prototype investment castings is becoming more feasible as we continue to successfully yield experimental castings by the SHELL'' processing method. This supplemental (to 11/90 publication) report briefly reviews the original project objectives, activities related to these objectives since November 1990, and progress made through December 1991. We discuss several new case studies involving new resin materials (and other materials) tested along with investment casting processing results. The most recent success, the processing of the highly complex C'' HOUSING design by the shell'' mold process in both aluminum and steel, will be discussed. This is considered a major breakthrough toward establishing this new technology as a viable approach to the rapid development of prototype investment castings, employing the most common aerospace (precision) cast process. Our future planning calls for expanding the study to help the investment casting industry in refining related processing techniques and to continue our evaluation of new resins suitable for the casting process. Present project planning calls for the completion of this study by the third quarter FY93 or sooner. We believe that with the continued excellent cooperation of our casting supplier study team and an accelerated effort by resin materials producers to further refine related materials, we can achieve all objectives during the planned time frame.

  15. Biotransformation and ToxCast

    EPA Science Inventory

    A major focus in toxicology research is the development of in vitro methods to predict in vivo chemical toxicity. Within the EPA ToxCast program, a broad range of in vitro biochemical and cellular assays have been deployed to profile the biological activity of 320 ToxCast Phase I...

  16. Lost-Soap Aluminum Casting.

    ERIC Educational Resources Information Center

    Mihalow, Paula

    1980-01-01

    Lost-wax casting in sterling silver is a costly experience for the average high school student. However, this jewelry process can be learned at no cost if scrap aluminum is used instead of silver, and soap bars are used instead of wax. This lost-soap aluminum casting process is described. (Author/KC)

  17. Casting Freedom, 1860-1862

    ERIC Educational Resources Information Center

    Social Education, 2005

    2005-01-01

    Thomas Crawford, an American Sculptor, created the full-size figure of Freedom in clay. Molds were made, from which a full-size positive plaster model was cast in five main sections. This model is on view today in the basement rotunda of the Russell Senate Office Building. Clark Mills was a self-taught American sculptor with experience in casting

  18. Antimicrobial-coated polypropylene films with polyvinyl alcohol in packaging of fresh beef.

    PubMed

    Han, Chunyang; Wang, Jianqing; Li, Yang; Lu, Fei; Cui, Yan

    2014-02-01

    The utility of packaging films consisting of cast polypropylene/polyvinyl alcohol with rhubarb ethanolic extracts (REE) and cinnamon essential oil (CEO) in maintaining fresh beef quality was investigated. Fresh beefsteaks were packed with antimicrobial films containing different concentrations of REE and CEO. Beef characteristics, including pH, total viable counts, instrumentally measured color, weight loss, total volatile base nitrogen (TVB-N) and sensory quality were determined. All experimental films significantly inhibited bacterial growth (p<0.05) and maintained the pH and TVB-N of beefsteaks. Three of four experimental films significantly reduced instrumental color loss (p<0.05). Antimicrobial packaging films efficiently maintained the quality of fresh beefsteaks during storage. PMID:24211547

  19. Wound Healing Bionanocomposites Based on Castor Oil Polymeric Films Reinforced with Chitosan-Modified ZnO Nanoparticles.

    PubMed

    Díez-Pascual, Ana M; Díez-Vicente, Angel L

    2015-09-14

    Castor oil (CO), which is a readily available, relatively inexpensive, and environmentally benign nonedible oil, has been successfully used as matrix material to prepare biocompatible and biodegradable nanocomposite films filled with chitosan (CS)-modified ZnO nanoparticles. The biocomposites were synthesized via a simple and versatile solution mixing and casting method. The morphology, structure, thermal stability, water absorption, biodegradability, cytocompatibility, barrier, mechanical, viscoelastic, antibacterial, and wound healing properties of the films have been analyzed. FT-IR spectra were used to obtain information about the nanoparticle-matrix interactions. The thermal stability, hydrophilicity, degree of porosity, water absorption, water vapor transmission rate (WVTR), oxygen permeability (Dk), and biodegradability of the films increased with the CS-ZnO loading. The WVTR and Dk data obtained are within the range of values reported for commercial wound dressings. Tensile tests demonstrated that the nanocomposites displayed a good balance between elasticity, strength, and flexibility under both dry and simulated body fluid (SBF) environments. The flexibility increased in a moist atmosphere due to the plasticization effect of absorbed water. The nanocomposites also exhibited significantly enhanced dynamic mechanical performance (storage modulus and glass transition temperature) than neat CO under different humidity conditions. The antibacterial activity of the films against Escherichia coli, Staphylococcus aureus, and Micrococcus luteus bacteria was investigated in the presence and the absence of UV light. The biocide effect increased progressively with the CS-ZnO content and was systematically stronger against Gram-positive cells. Composites with nanoparticle loading ?5.0 wt % exhibited very good in vitro cytocompatibility and enabled a faster wound healing than neat CO and control gauze, hence showing great potential to be applied as antibacterial wound dressings. PMID:26302315

  20. Photoredox pathways to spatially restricted metallopolymeric films

    SciTech Connect

    Subramanian, P.; Zhang, Haitao; Hupp, J.T. )

    1992-04-15

    There now exists an extensive body of synthesis and applications-based chemistry for redox-active metallopolymeric films. The applications include electrochemical catalysis, energy conversion, electrochromic displays, analysis, and molecular and ionic sensing. Films for these purposes are most commonly assembled via electrochemically initiated radical polymerization pathways or, less often, by simple spin casting of preformed metallopolymers (or metal-free polymer backbones). Both approaches lead to films of more or less uniform composition, which effectively cover the entire available exposed surface support area. In pursuit of additional applications (remote optical sensing and advanced electrochromics), the authors have devised an additional method for assembling films. The new approach, which is based on simple redox quenching processes following photochemical excitation, was designed to meet three specific requirements: (1) film assembly on transparent surfaces, (2) spatially selective assembly, and (3) assembly, if necessary, on insulating surfaces. While some of these objectives can be achieved with existing synthetic or assembly methods, for any given system it is difficult to achieve all three simultaneously. As indicated below, however, they have been reasonably successful in reaching these goals by employing a straightforward photoredox approach.