These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Control system of the film casting based on the fieldbus  

Microsoft Academic Search

In this paper, the technology of the film casting is briefly introduced. According to the requirements of the system, an automatic control system is designed. In the system, PLC and host computer are used as the core,and the Profibus-DP fieldbus is used to communication.The overall framework of the control system is introduced in the paper, and the control strategy of

Xiaoyong Xu; Yu Sun; Hongmei Fan

2010-01-01

2

Vacuum casting of thick polymeric films  

NASA Technical Reports Server (NTRS)

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.

Cuddihy, E. F.; Moacanin, J.

1979-01-01

3

Refractory films from spin-cast polyacrylonitrile  

SciTech Connect

Polyacrylonitrile (PAN) films have been spin-cast and pyrolyzed to produce thin (500 to 1500 A) carbon films. These films have higher electrical conductivities than carbon films produced by other methods at similar temperatures. The conductivity can be varied by at least four orders of magnitude by changing the pyrolysis temperature. UV, IR, and Raman spectroscopies were used to investigate the chemical structure of the films during different stages of processing.

Renschler, C.L.; Sylwester, A.P.

1987-01-01

4

Refractory films from spin-cast carbon  

SciTech Connect

A method is described to produce thin films of carbon by the pyrolysis of spin-cast polyacrylonitrile. Uv, ir, and Raman spectroscopies were employed to investigate the chemical structure of the films during pyrolysis. The electrical conductivity of films made in this way can be varied over several decades by changing the final temperature of carbonization. These films can also be photolithographically patterned and manipulated by wet and dry transfer techniques. As such, these films may have utility in microelectronic and hybrid microcircuit applications. 7 refs., 4 figs.

Renschler, C.L.; Sylwester, A.P.

1988-01-01

5

Spin-cast carbon films from polyacrylonitrile  

SciTech Connect

Carbon films have been made by a variety of techniques, including evaporation, sputtering, and laser or thermal pyrolysis of organic polymers. Polyacrylonitrile (PAN) is often used as a carbon precursor, since low-temperature thermo-oxidative pretreatment produces a material which can be pyrolyzed without loss of shape. This is the basis for the production of carbon fibers with good mechanical properties. We report here the formation of very thin films of carbon (500 to 1500 A) by pyrolysis of spin-cast PAN. Using this technique, large, conductive films can be made which are sufficiently robust to allow intact lift-off and transfer of the films from one substrate to another. Such films are chemically inert, but can be photolithographically patterned and etched with an oxygen plasma.

Renschler, C.L.; Sylwester, A.P.

1987-01-01

6

Melting and casting of FeAl-based cast alloy  

SciTech Connect

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

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

1998-11-01

7

Oxygen permeability of cast ionomer films from chronoamperometry on microelectrodes  

NASA Astrophysics Data System (ADS)

The paper presents a method for determination of diffusion coefficient and solubility of oxygen in cast polymer electrolyte from chronoamperometry of oxygen on polymer electrolyte coated platinum disk ultramicroelectrodes. The approach is based on numerical fitting of measured currents to the known but not previously used for polymer electrolytes equation derived by Shoup and Szabo. The method was applied to cast films of a novel polymer electrolyte 6F-40. As opposed to Nafion®, cast 6F-40 films do not undergo interfacial restructuring, i.e., they retain their original morphology under selected temperature and humidity conditions, which allows for accurate determination of both parameters from measurements for a range of electrode radii and film thicknesses. It is demonstrated that the Shoup and Szabo equation satisfactorily describes measured current transients for shorter oxygen reduction times, i.e., when the diffusion field in the thin polymer film can be regarded as semiinfinite. The accuracy of the diffusion coefficient and solubility determinations was not measurably affected by the product water and the observed systematic changes of the fit quality in various time domains were attributed to approximate character of the fitting equation.

Chlistunoff, Jerzy

2014-01-01

8

FTIR study of water in cast Nafion films  

Microsoft Academic Search

The state of water in cast perfluorosulphonic Nafion films has been investigated using Fourier transform infrared spectroscopy (FTIR). FTIR spectra of cast Nafion films equilibrated in different relative humidities (RH) in a non flowing vapour environment, and in 100% RH at different temperatures have been made. In contrast to previously published results on thicker membranes the FTIR experiments indicate that

M Ludvigsson; J Lindgren; J Tegenfeldt

2000-01-01

9

Residual stress in spin-cast polyurethane thin films  

NASA Astrophysics Data System (ADS)

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

Zhang, Hong; Zhang, Li

2015-01-01

10

Non-equilibrium behavior of spin-cast films  

NASA Astrophysics Data System (ADS)

The behavior of polystyrene films cast from various solvents using an electric field to weakly perturb the free surface of the polymer melt was examined. The effective viscosity and residual stresses of the as-spun films strongly depend on the casting solvent. As-cast films had a substantially reduced viscosity compared to annealed films, with the greatest reduction in films cast from solutions near ?-temperature. The reduced viscosity is explained in terms of non-equilibrium effects from the film formation process; rapid quenching during spin-coating results in a lower entanglement density of chains compared to an equilibrium melt. The difference in films spun from the various solvents is explained by changes in chain conformations in the initial solutions and the vitrification point. The wavelength of the instabilities in as-cast films was higher than expected, indicating a weak stabilizing pressure. This is attributed to frozen-in normal stresses resulting from an asymmetric deformation of the chains due to evaporation of residual solvent after vitrification. The results show the non-equilibrium nature of as-cast polymer films and that processing conditions strongly influence their behavior.

Thomas, Katherine

2011-03-01

11

RELIABILITY-BASED CASTING PROCESS DESIGN OPTIMIZATION  

E-print Network

RELIABILITY-BASED CASTING PROCESS DESIGN OPTIMIZATION Richard Hardin1 , K.K. Choi1 , and Christoph 52242-1527 Keywords: Casting Process Design, Optimization, Reliability-Based Design Optimization Abstract Optimum casting designs are unreliable without consideration of the statistical and physical

Beckermann, Christoph

12

Conductive, spin-cast carbon films from polyacrylonitrile  

SciTech Connect

Polyacrylonitrile films have been spin cast and pyrolyzed to produce thin (500--1500 A) carbon films. These films have higher electrical conductivities than films produced by other methods at similar temperatures. The conductivity can be varied by at least four orders of magnitude by changing the pyrolysis temperature. Ultraviolet, infrared, and Raman spectroscopies were used to investigate the chemical structure of the films during different stages of processing.

Renschler, C.L.; Sylwester, A.P.

1987-05-18

13

Land-based turbine casting initiative  

SciTech Connect

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.

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

1995-12-31

14

Bifilm Defects in Ni-Based Alloy Castings  

NASA Astrophysics Data System (ADS)

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.

Campbell, John; Tiryakio?lu, Murat

2012-08-01

15

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

PubMed

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

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

2015-03-01

16

On the membrane approximation in isothermal film casting  

NASA Astrophysics Data System (ADS)

In this work, a one-dimensional model for isothermal film casting is studied. Film casting is an important engineering process to manufacture thin films and sheets from a highly viscous polymer melt. The model equations account for variations in film width and film thickness, and arise from thinness and kinematic assumptions for the free liquid film. The first aspect of our study is a rigorous discussion of the existence and uniqueness of stationary solutions. This objective is approached via the argument principle, exploiting the homotopy invariance of a family of analytic functions. As our second objective, we analyze the linearization of the governing equations about stationary solutions. It is shown that solutions for the associated boundary-initial value problem are given by a strongly continuous semigroup of bounded linear operators. To reach this result, we cast the relevant Cauchy problem in a more accessible form. These transformed equations allow us insight into the regularity of the semigroup, thus yielding the validity of the spectral mapping theorem for the semigroup and the spectrally determined growth property.

Hagen, Thomas

2014-08-01

17

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 ...

18

Characterization of Drop Casted CuTsPc Films on Ito Substrates  

NASA Astrophysics Data System (ADS)

This study evaluated the possibility of utilizing a drop-cast process for CuTsPc-based organic solar cells. CuTsPc thin films were deposited by drop-cast method on ITO substrate. The absorption spectra of these films show two well-defined absorption bands of phthalocyanine molecule, namely, the soret (B) and Q-band. The band gaps calculated from the absorption spectra is found to lie in the range of 1.55-4.04 eV. X-ray diffractogram of the films indicate their polycrystalline nature. Atomic force microscope (AFM) investigations of the films show granular grain like morphology. The data for mobility, dielectric constant, extinction coefficient and refractive index are also presented in this communication.

Mahajan, Aman; Kumar, Anshul; Singh, Mandeep; Pathak, Dinesh; Bedi, R. K.

2013-02-01

19

Tape casting and partial melting of Bi-2212 thick films  

SciTech Connect

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

Buhl, D.; Lang, T.; Heeb, B. [Nichtmetallische Werkstoffe, Zuerich (Switzerland)] [and others

1994-12-31

20

Tape casting and partial melting of Bi-2212 thick films  

NASA Technical Reports Server (NTRS)

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).

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

1995-01-01

21

The cast aluminum denture base. Part II: Technique.  

PubMed

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

Halperin, A R; Halperin, G C

1980-07-01

22

CAST  

NSDL National Science Digital Library

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

2012-02-03

23

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

SciTech Connect

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.

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

2014-01-01

24

Aging properties of films of plasticized vital wheat gluten cast from acidic and basic solutions.  

PubMed

In order to understand the mechanisms behind the undesired aging of films based on vital wheat gluten plasticized with glycerol, films cast from water/ethanol solutions were investigated. The effect of pH was studied by casting from solutions at pH 4 and pH 11. The films were aged for 120 days at 50% relative humidity and 23 degrees C, and the tensile properties and oxygen and water vapor permeabilities were measured as a function of aging time. The changes in the protein structure were determined by infrared spectroscopy and size-exclusion and reverse-phase high-performance liquid chromatography, and the film structure was revealed by optical and scanning electron microscopy. The pH 11 film was mechanically more stable with time than the pH 4 film, the latter being initially very ductile but turning brittle toward the end of the aging period. The protein solubility and infrared spectroscopy measurements indicated that the protein structure of the pH 4 film was initially significantly less polymerized/aggregated than that of the pH 11 film. The polymerization of the pH 4 film increased during storage but it did not reach the degree of aggregation of the pH 11 film. Reverse-phase chromatography indicated that the pH 11 films were to some extent deamidated and that this increased with aging. At the same time a large fraction of the aged pH 11 film was unaffected by reducing agents, suggesting that a time-induced isopeptide cross-linking had occurred. This isopeptide formation did not, however, change the overall degree of aggregation and consequently the mechanical properties of the film. During aging, the pH 4 films lost more mass than the pH 11 films mainly due to migration of glycerol but also due to some loss of volatile mass. Scanning electron and optical microscopy showed that the pH 11 film was more uniform in thickness and that the film structure was more homogeneous than that of the pH 4 film. The oxygen permeability was also lower for the pH 11 film. The fact that the pH 4 film experienced a larger and more rapid change in its mechanical properties with time than the pH 11 film, as a consequence of a greater loss of plasticizer, was presumably due to its initial lower degree of protein aggregation/polymerization. Consequently, the cross-link density achieved at pH 4 was too low to effectively retain volatiles and glycerol within the matrix. PMID:16677051

Olabarrieta, Idoia; Cho, Sung-Woo; Gällstedt, Mikael; Sarasua, Jose-Ramon; Johansson, Eva; Hedenqvist, Mikael S

2006-05-01

25

Numerical modelling of entrainment of oxide film defects in filling of aluminium alloy castings  

Microsoft Academic Search

Recent advances in understanding the filling process during casting have indicated that metal flow conditions play key roles in controlling the quality of the casting.2,15 Inappropriate filling of castings usually cause surface oxide films to be folded into the bulk liquid or broken due to a higher liquid metal kinematic energy, resulting in so-called \\

Xiaogang Yang; Xiaobing Huang; Xiaojun Dai; John Campbell; Joe Tatler

2004-01-01

26

Adaptive GPU Ray Casting Based on Spectral Stefan Suwelack1  

E-print Network

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

Paris-Sud XI, Université de

27

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

E-print Network

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

Paris-Sud XI, Université de

28

Electroconductive PET/SWNT Films by Solution Casting  

NASA Technical Reports Server (NTRS)

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.

Steinert, Brian W.; Dean, Derrick R.

2008-01-01

29

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

PubMed

The antimicrobial activities against Escherichia coli O157:H7 as well as the stability of carvacrol, the main constituent of oregano oil, were evaluated during the preparation and storage of apple-based edible films made by two different casting methods, continuous casting and batch casting. Antimicrobial assays of films and high-performance liquid chromatography (HPLC) analysis of film extracts following storage up to 49 days at 5 and 25 degrees C revealed that (a) optimum antimicrobial effects were apparent with carvacrol levels of approximately 1.0% added to the purees prior to film preparation, (b) carvacrol in the films and film weights remained unchanged over the storage period of up to 7 weeks, and (c) casting methods affected carvacrol concentration, bactericidal activity, physicochemical properties, and colors of the apple films. Carvacrol addition to the purees used to prepare the films reduced water vapor and oxygen permeability of apple films. The results indicate that carvacrol has a dual benefit. It can be used to both impart antimicrobial activities and enhance barrier properties of edible films. The cited observations facilitate relating compositional and physicochemical properties of apple puree films containing volatile plant antimicrobials to their use in foods. PMID:18366181

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

2008-05-14

30

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

NASA Astrophysics Data System (ADS)

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.

Wróbel, Tomasz

2014-05-01

31

Gelation of a solution of poly(3-hexylthiophene) greatly retards its crystallization rate in the subsequently cast film.  

PubMed

We compared the crystallization rate of poly(3-hexylthiophene) (P3HT) in the film cast from the gel (called "gel-cast film") with that in the film cast from the liquid solution (called "solution-cast film") to understand the effect of solution structure on the structural development in the subsequently cast film of conjugated polymer. P3HT was found to form a homogeneous liquid solution with xylene at elevated temperature. When the freshly prepared semidilute solution was allowed to age at room temperature, the solution transformed into a gel in which a significant amount of nanowhiskers formed. The nanowhiskers in the gel were effectively transferred to the corresponding cast film, while the film cast from the freshly prepared solution only contained a small amount of such a morphological entity. The in situ small-angle X-ray scattering (SAXS) measurement and thermal analysis revealed that both the cold and melt crystallization of P3HT in the gel-cast film were much slower than those in the solution-cast counterpart. The retardation of crystallization rate in the gel-cast film was attributed to the abundance of the nanowhiskers. In this case, the crystallization of P3HT occurred predominantly within the individual nanowhiskers and the mesh regions in the networks of the whiskers, where their limited sizes in at least one dimension imposed a strong spatial constraint to the crystal growth and chain motion for crystallization. PMID:25406068

Kao, Kuei-Yu; Lo, Shen-Chuan; Chen, Hsin-Lung; Chen, Jean-Hong; Chen, Show-An

2014-12-11

32

Effect of casting solvent on crystallinity of ondansetron in transdermal films.  

PubMed

The purpose of the present investigation is to assess the influence of casting solvent on crystallinity of ondansetron hydrochloride in transdermal polymeric matrix films fabricated using povidone and ethyl cellulose as matrix forming polymers. Various casting solvents like chloroform (CHL), dichloromethane (DCM), methanol (MET); and mixture of chloroform and ethanol (C-ETH) were used for fabrication of the transdermal films. Analytical tools like scanning electron microscopy (SEM), X-ray diffraction (XRD) studies, differential scanning calorimetry (DSC), etc. were utilized to characterize the crystalline state of ondansetron in the film. Recrystallisation was observed in all the transdermal films fabricated using the casting solvents other than chloroform. Long thin slab-looking, long wire-like or spherulite-looking crystals with beautiful impinged boundaries were observed in SEM. Moreover, XRD revealed no crystalline peaks of ondansetron hydrochloride in the transdermal films prepared using chloroform as casting solvent. The significantly decreased intensity and sharpness of the DSC endothermic peaks corresponding to the melting point of ondansetron in the formulation (specifically in CHL) indicated partial dissolution of ondansetron crystals in the polymeric films. The employed analytical tools suggested chloroform as a preferred casting solvent with minimum or practically absence of recrystallization indicating a relatively amorphous state of ondansetron in transdermal films. PMID:21237257

Pattnaik, Satyanarayan; Swain, Kalpana; Mallick, Subrata; Lin, Zhiqun

2011-03-15

33

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, ...

34

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

E-print Network

, in series is given by: eff = t t polymer + 1 G -1 2 as a function of film thickness. AccordingInterfacial thermal conductance in spun-cast polymer films and polymer brushes Mark D. Losego inorganic materials and anharmonic polymers have potentially intriguing thermal transport behavior. The low

Braun, Paul

35

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

E-print Network

SUPPLEMENTAL INFORMATION FOR: Interfacial thermal conductance in spun-cast polymer films surfaces from toluene. Films were dried for 4 hrs at 50°C in vacuum (~10-2 Torr) to remove the solvent) following the procedures described by Gorman et al.4 Copper (I) chloride was used as the catalyst. Brush

Braun, Paul

36

Grain Refinement of Permanent Mold Cast Copper Base Alloys  

SciTech Connect

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.

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

2005-04-01

37

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

Microsoft Academic Search

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

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

2011-01-01

38

Reversible tuning of chemical structure of nafion cast film by heat and Acid treatment.  

PubMed

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

Singhal, Nancy; Datta, Anindya

2015-02-12

39

Fatty acid-based polyurethane films for wound dressing applications  

Microsoft Academic Search

Fatty acid-based polyurethane films were prepared for use as potential wound dressing material. The polymerization reaction\\u000a was carried out with or without catalyst. Polymer films were prepared by casting-evaporation technique with or without crosslink-catalyst.\\u000a The film prepared from uncatalyzed reaction product with crosslink-catalyst gave slightly higher crosslink density. The mechanical\\u000a tests showed that, the increase in the tensile strength and

Guncem Gultekin; Cigdem Atalay-Oral; Sibel Erkal; Fikret Sahin; Djursun Karastova; S. Birgul Tantekin-Ersolmaz; F. Seniha Guner

2009-01-01

40

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

PubMed

Abstract 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

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

2014-09-01

41

Antireflective polyimide based films  

NASA Astrophysics Data System (ADS)

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

Cao, Yuanmei

42

Characterization of thin film properties of melamine based dendrimer nanoparticles  

E-print Network

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

Boo, Woong Jae

2005-02-17

43

Aluminum-Based Cast In Situ Composites: A Review  

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

44

Study on theoretical bases of receiving composite alloy layers on surface of cast steel castings  

Microsoft Academic Search

The use of composite alloy layers on chosen surfaces of cast makes possible to obtain a special usable properties. Composite alloy layers on cast steel shapes with liquid phase. The processes which set in form during formation of composite layer, progress beside the transient heat flow that the transient thermal field. Decrease of temperature in surface layer of cast causes

J. Gawro?ski; J. Szajnar; P. Wróbel

2004-01-01

45

Structural and orientational studies of chiral N-[4(1-pyrene)butyroyl]-phenylalanine in cast film  

NASA Astrophysics Data System (ADS)

Cast films of chiral material N-[4(1-pyrene)butyroyl]- L-phenylalanine (Py- L-Phe) and the racemic modification (the 1:1 mixture of Py- L-Phe and Py- D-Phe) have been investigated in the present study. The microscopic structure, molecular orientation and the aggregation in the film have been studied by using ultraviolet-visible (UV-vis) and infrared (IR) spectroscopy. When a cast film is formed from the chloroform solution at room temperature, the J-aggregates of Py- L-Phe and Py- D-Phe are observed by UV-vis spectra. A comparison of Fourier transform infrared (FT-IR) transmission and reflection-absorption (RA) spectroscopy has been applied to reveal the orientation and structural characterization of the cast films. It has been found that the pyrenyl ring in the cast film of Py- L-Phe assumes a nearly vertical orientation with respect to the surface of the solid substrate. And there are two different hydrogen bonding species, cyclic dimer and linear dimer, exist in carboxyl groups in cast films. The detailed analysis of the O sbnd H and N sbnd H stretching modes of Py- L-Phe and Py- D-Phe allows us to reveal the hydrogen bonds existing in the films.

Zhai, Chunxi; Li, Wen; Ma, Lijun; Wu, Lixin; Wu, Yuqing

2005-09-01

46

Cast iron-base alloy for cylinder/regenerator housing  

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

47

Continuous Casting Slag Detection Expert System Based on CLIPS  

Microsoft Academic Search

In order to resolve the pouring state recognition problem of continuous casting slag detection system (CC-SDS) and reduce its control delay, a kind of C language integrated production system (CLIPS) based CC slag detection expert system (SDES) was brought forward. Multi-channel real-time vibration signal collection system oriented to slag detection was established, and it could supply stable real-time support for

Da-peng Tan; Shi-ming Ji; Shu-ting Chen

2010-01-01

48

Method of casting pitch based foam  

DOEpatents

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.

Klett, James W. (Knoxville, TN)

2002-01-01

49

Casting of particle-based hollow shapes  

DOEpatents

A method for the production of hollow articles made of a particle-based material; e.g., ceramics and sintered metals. In accordance with one aspect of the invention, a thermally settable slurry containing a relatively high concentration of the particles is coated onto a prewarmed continuous surface in a relatively thin layer so that the slurry is substantially uniformly coated on the surface. The heat of the prewarmed surface conducts to the slurry to initiate a reaction which causes the slurry to set or harden in a shape conforming to the surface. The hardened configurations may then be sintered to consolidate the particles and provide a high density product.

Menchhofer, Paul (Oak Ridge, TN)

1995-01-01

50

Casting of particle-based hollow shapes  

DOEpatents

A method for the production of hollow articles made of a particle-based material; e.g., ceramics and sintered metals. In accordance with one aspect of the invention, a thermally settable slurry containing a relatively high concentration of the particles is coated onto a prewarmed continuous surface in a relatively thin layer so that the slurry is substantially uniformly coated on the surface. The heat of the prewarmed surface conducts to the slurry to initiate a reaction which causes the slurry to set or harden in a shape conforming to the surface. The hardened configurations may then be sintered to consolidate the particles and provide a high density product.

Menchhofer, Paul (Oak Ridge, TN)

1997-01-01

51

Casting of particle-based hollow shapes  

DOEpatents

A method is disclosed for the production of hollow articles made of a particle-based material; e.g., ceramics and sintered metals. In accordance with one aspect of the invention, a thermally settable slurry containing a relatively high concentration of the particles is coated onto a prewarmed continuous surface in a relatively thin layer so that the slurry is substantially uniformly coated on the surface. The heat of the prewarmed surface conducts to the slurry to initiate a reaction which causes the slurry to set or harden in a shape conforming to the surface. The hardened configurations may then be sintered to consolidate the particles and provide a high density product. 9 figs.

Menchhofer, P.

1997-09-09

52

Casting of particle-based hollow shapes  

DOEpatents

A method is disclosed for the production of hollow articles made of a particle-based material; e.g., ceramics and sintered metals. In accordance with one aspect of the invention, a thermally settable slurry containing a relatively high concentration of the particles is coated onto a prewarmed continuous surface in a relatively thin layer so that the slurry is substantially uniformly coated on the surface. The heat of the prewarmed surface conducts to the slurry to initiate a reaction which causes the slurry to set or harden in a shape conforming to the surface. The hardened configurations may then be sintered to consolidate the particles and provide a high density product. 9 figs.

Menchhofer, P.

1995-05-30

53

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

PubMed Central

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

2014-01-01

54

GRAIN REFINEMENT OF PERMANENT MOLD CAST COPPER BASE ALLOYS  

Microsoft Academic Search

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

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

2004-01-01

55

Crystallizaion and surface morphology of poly(vinylidene fluoride)/poly(methylmethacrylate) films by solution casting on different substrates  

NASA Astrophysics Data System (ADS)

The dependence of surface structure of the poly(vinylidene fluoride) (PVDF)/poly(methylmethacrylate) (PMMA) films by solution casting on properties of seven substrates was investigated by wide angle X-ray diffraction (WAXD), Fourier transform infrared (FTIR), scanning electron microscope (SEM) and differential scanning calorimetry (DSC). It was revealed that the polyblend films obtained by casting onto each substrate contained exclusively ? phase PVDF. Higher crystallinity of the film was obtained by casting onto ceramic, polytetrafluoroethylene (PTFE), copper (Cu), stainless steel and glass substrates than that by casting onto aluminium (Al) and polypropylene (PP) substrates, depending on the degree of close lattice matching. The surface crystalline structure of PVDF was strongly affected by the wettability of substrate. The largest size of PVDF spherulitic crystal structure with about 6 ?m presented in the casting film grown at the air/solution interface on glass substrate, while the smallest spherulite size with about 3 ?m was generated by casting onto PTFE, stainless steel and PP substrates. It implied that the higher surface tension the substrate had, the larger PVDF spherulite grew at the air/solution interface.

Ma, Wenzhong; Zhang, Jun; Wang, Xiaolin

2008-03-01

56

Streaming Model Based Volume Ray Casting Implementation for Cell Broadband Engine  

E-print Network

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

JaJa, Joseph F.

57

Improving drug loading of mucosal solvent cast films using a combination of hydrophilic polymers with amoxicillin and paracetamol as model drugs.  

PubMed

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

Boateng, Joshua; Mani, Justine; Kianfar, Farnoosh

2013-01-01

58

Relating hydrogen-bonding interactions with the phase behavior of naproxen/PVP K 25 solid dispersions: evaluation of solution-cast and quench-cooled films.  

PubMed

In this work, we investigated the relationship between various intermolecular hydrogen-bonding (H-bonding) interactions and the miscibility of the model hydrophobic drug naproxen with the hydrophilic polymer polyvinylpyrrolidone (PVP) across an entire composition range of solid dispersions prepared by quasi-equilibrium film casting and nonequilibrium melt quench cooling. The binary phase behavior in solid dispersions exhibited substantial processing method dependence. The solid state solubility of crystalline naproxen in PVP to form amorphous solid dispersions was 35% and 70% w/w naproxen in solution-cast films and quench-cooled films, respectively. However, the presence of a single mixed phase glass transition indicated the amorphous miscibility to be 20% w/w naproxen for the films, beyond which amorphous-amorphous and/or crystalline phase separations were apparent. This was further supported by the solution state interactions data such as PVP globular size distribution and solution infrared spectral profiles. The borderline melt composition showed cooling rate dependence of amorphization. The glass transition and melting point depression profiles of the system were treated with the analytical expressions based on Flory-Huggins mixing theory to interpolate the equilibrium solid solubility. FTIR analysis and subsequent spectral deconvolution revealed composition and miscibility dependent variations in the strength of drug-polymer intermolecular H-bonding. Two types of H-bonded populations were evidenced from 25% w/w and 35% w/w naproxen in solution-cast films and quench-cooled films, respectively, with the higher fraction of strongly H-bonded population in the drug rich domains of phase separated amorphous film compositions and highly drug loaded amorphous quench-cooled dispersions. PMID:23009610

Paudel, Amrit; Nies, Erik; Van den Mooter, Guy

2012-11-01

59

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

NASA Astrophysics Data System (ADS)

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

Sun, Mingzhu; Downes, Sandra

2007-07-01

60

Cast Fe-base cylinder/regenerator housing alloy  

NASA Technical Reports Server (NTRS)

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.

Larson, F.; Kindlimann, L.

1980-01-01

61

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

PubMed

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

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

2014-04-18

62

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

PubMed

This paper describes the design and performance of a new instrument to track temporal changes in physical parameters during the drying behavior of solutions, as well as curing of monomers. This real-time instrument follows in-plane and out-of-plane birefringence, weight, thickness, and surface temperature during the course of solidification of coatings and films through solvent evaporation and thermal or photocuring in a controlled atmosphere. It is specifically designed to simulate behavior of polymer solutions inside an industrial size, continuous roll-to-roll solution casting line and other coating operations where resins are subjected to ultraviolet (UV) curing from monomer precursors. Controlled processing parameters include air speed, temperature, initial cast thickness, and solute concentration, while measured parameters are thickness, weight, film temperature, in-plane and out-of-plane birefringence. In this paper, we illustrate the utility of this instrument with solution cast and dried poly (amide-imide)?DMAc (Dimethylacetamide) solution, water based black paint, and organo-modified clay?NMP (N-Methylpyrrolidone) solution. In addition, the physical changes that take place during UV photo polymerization of a monomer are tracked. This instrument is designed to be generic and it can be used for tracking any drying?swelling?solidification systems including paper, foodstuffs such as; grains, milk as well as pharmaceutical thin paste and slurries. PMID:22380132

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

2012-02-01

63

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

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

64

Conducting film-forming composites based on polyaniline-polyimide blends  

Microsoft Academic Search

A procedure is developed for preparing conducting films by their casting from polymer solutions containing polyaniline in\\u000a the form of a protonated emeraldin base and polyimides in two cosolvents, N-methylpyrrolidone or m-cresol. Self-supporting films cast from composites based on polyimides and camphorsulfonic acid-protonated polyaniline combine\\u000a a conductivity of 10?1?10?2S\\/cm with good mechanical properties: elastic modulus E = 2.0?2.4 GPa, breaking

T. K. Meleshko; I. G. Sushchenko; N. N. Bogorad; I. V. Gofman; V. M. Svetlichnyi; E. Yu. Rozova; G. K. El’yashevich; V. V. Kudryavtsev; A. V. Yakimanskii

2009-01-01

65

New polyurethane-based material for vascular corrosion casting with improved physical and imaging characteristics.  

PubMed

Vascular corrosion casting has been established as a method to reconstruct the three-dimensional (3D) structure of blood vessels of organs and tissues. After replacing the blood volume with a low viscosity resin, the surrounding tissue is removed to replicate the vascular architecture, typically using scanning electron microscopy (SEM). To date available casting resins have had significant limitations such as lack of viscosity, leading to insufficient perfusion of smallest capillaries in organs and tissues of smaller species, interaction with surrounding tissue or fragility of resulting casts. We have reported here about a new polyurethane-based casting resin (PU4ii) with superior physical and imaging characteristics. Low viscosity, timely polymerization, and minimal shrinking of PU4ii produces high quality casts, including the finest capillaries. These casts are highly elastic while retaining their original structure to facilitate postcasting tissue dissection and pruning of casts. SEM images illustrate the high reproduction quality, including endothelial cell imprints, features that allow one to discern arterial and veinal vessels. For quantitative analysis, casts from PU4ii can be imaged using micro-computed tomography to produce digital 3D reconstructions. The inherent fluorescence of PU4ii is sufficient to reproduce casts with or without tissue using confocal microscopy (CM). Because of the simplified casting procedure, the high reproducibility and the superior reproduction quality, a combination of vascular corrosion casting using PU4ii with advanced imaging technologies has great potential to support the description of vascular defects and drug effects in disease models using mutant mice. PMID:16456839

Krucker, Thomas; Lang, Axel; Meyer, Eric P

2006-02-01

66

Degradation mechanism of poly(lactic- co-glycolic) acid block copolymer cast films in phosphate buffer solution  

Microsoft Academic Search

We have investigated the degradation of poly(lactic-co-glycolic) acid copolymer with a lactic to glycolic ratio of 50:50. Solvent-cast films were incubated at 37°C in phosphate buffered saline solution and their degradation was followed using potentiometry, light microscopy, gravimetry, size exclusion chromatography, differential scanning calorimetry and infrared spectroscopy. The degradation process was found to have two main steps. The first step

Elisabeth Vey; Caroline Roger; Liz Meehan; Jonathan Booth; Mike Claybourn; Aline F. Miller; Alberto Saiani

2008-01-01

67

Burnishability of a nickel and a cobalt base casting alloys.  

PubMed

A specially designed stainless steel split die capable of producing a total of 24 half cylindrical shaped wax patterns was used in this study. The burnishability of two non-precious casting alloys was evaluated following a proposed softening heat treatment technique. A practical easily applied burnishing tool was introduced. Results have shown that, both of the non-precious alloys were burnishable following softening heat treatment. However, nickel-chromium alloy was significantly more burnishable than the cobalt-chromium alloy. It is suggested that clinical implications of the developed technique in this study would be an important additive for more precision castings. PMID:2701428

Nasr, H H; Mosleh, I

1989-10-01

68

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

NASA Astrophysics Data System (ADS)

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.

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

2013-07-01

69

The Status of Dalit Women in India's Caste Based System  

Microsoft Academic Search

In this paper I wish to present the devastating effects of the caste system on the educational, social, and economical status of Dalit women in modern India. My aim is to highlight the harsh reality of the suppression, struggle and torture Dalit women face every day of their miserable lives. The hardships of Dalit women are not simply due to

Sonia Mahey

70

Hardware-Based Ray Casting for Tetrahedral Meshes  

Microsoft Academic Search

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

Manfred Weiler; Martin Kraus; Markus Merz; Thomas Ertl

2003-01-01

71

Bio-inspired nacre-like composite films based on graphene with superior mechanical, electrical, and biocompatible properties.  

PubMed

Bio-inspired multifunctional composite films based on reduced poly(vinyl alcohol)/graphene oxide (R-PVA/GO) layers are prepared by a facile solution casting method followed by a reduction procedure. The resulting films with nacre-like, bricks-and-mortar microstructure have excellent mechanical properties, electrical conductivity, and biocompatibility. PMID:22730223

Li, Yuan-Qing; Yu, Ting; Yang, Tian-Yi; Zheng, Lian-Xi; Liao, Kin

2012-07-01

72

Comparison of biomechanical behavior between a cast material torso jacket and a polyethylene based jacket  

PubMed Central

Background Numerous designs are used to the treatment of Early Onset Scoliosis. For example, a Thoraco-Lumbo-Sacral Orthosis (TLSO) is constructed using Polyethylene (PE). In addition, a series of castings has been implemented using cast material (3M, BSN Medical). The cast material has some significant advantages over the PE design including: growth preserving, improved compliance, decreased invasiveness, delaying or avoiding surgery, and the ability to allow the skin to breathe. However, the mechanical effectiveness of the cast material brace as compared to the TLSO is unknown, thus providing the objective of this study. Methods A total of 23 standardized tensile tests were performed on the Delta-Cast Soft® and 3MTM ScotchcastTM Plus Casting Tape in order to obtain mechanical properties (Young’s and shear moduli and Poisson ratios). Using a radiograph of a thoracic spine, the size of twelve vertebrae and eleven intervertebral discs were measured and used to create a finite element spine model. Simulations using this model were used to establish mechanical loads which were then applied to finite element models of the TLSO and cast jacket. The thicknesses and number of material layers was varied in these models. Multiple simulations were performed. Results It was found that a 6.6.mm thick cast jacket made of Delta-Cast Soft® had a maximum deformation of 4.7 mm, a maximum stress of 2.9 MPa and a structural factor of safety of 5.71. On the other hand, a 4 mm thick jacket made of PE had a maximum deformation of 2 mm, a maximum stress of 8.9 MPa and a structural factor of safety of 2.70. The cast jacket was 3.5 times lighter and had a material of cost 1/5 of the PE brace. Conclusions Based on the results, either design will generate the proper constraint forces to maintain spinal correction. But, based on the design parameters (thickness, mechanical properties, structural factor of safety and cost) the brace made of cast material, though slightly thicker has superior structural and cost benefits. Thus, from the biomechanical point of view, the cast brace is more efficient than the PE brace. PMID:25815054

2015-01-01

73

High solids loading for water-based tape casting  

Microsoft Academic Search

Tape Casting is a low cost process for making large-area, thin, flat ceramics, which traditionally utilizes organic solvents to allow fast drying.sp{1-4} However, some of the volatile organic compounds (VOC), such as toluene, methylethyl ketone (MEK), and cyclohexanone, are hazardous air pollutants, and their emissions need to be regulated. Therefore, using water as a solvent is desirable to avoid the

Thitima Suwannasiri

1997-01-01

74

GRAIN REFINEMENT OF PERMANENT MOLD CAST COPPER BASE ALLOYS  

SciTech Connect

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

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

2004-04-29

75

Urinary casts  

MedlinePLUS

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

76

Low-Temperature Processing of Pb(Zr0.53,Ti0.43)O3 Thin Films by Sol-Gel Casting  

Microsoft Academic Search

This paper focuses on a new class of processing for the low-temperature deposition of relatively thick films. We propose a new process of sol-gel casting which involves the dispersion of fine crystalline particles in a sol-gel derived precursor solution followed by casting and annealing at relatively low temperatures. In this study, we describe the basic concepts for optimizing the process

Tomoya Ohno; Masahumi Kunieda; Hisao Suzuki; Takashi Hayashi

2000-01-01

77

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

NASA Astrophysics Data System (ADS)

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.

Das, Kunal; Maiti, Sonakshi; Liu, Dagang

2014-04-01

78

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 ...

79

Casting Technology.  

ERIC Educational Resources Information Center

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)

Wright, Michael D.; And Others

1992-01-01

80

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

Microsoft Academic Search

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

Simranpreet Singh Gill; Munish Kaplas

2011-01-01

81

Utility and Stability Measures for Agent-Based Dynamic Scheduling of Steel Continuous Casting  

Microsoft Academic Search

This paper describes a new model for robust predictive\\/reactive scheduling of steel continuous casting based on the use of multi-agents, tabu search and heuristic approaches. A continuous caster agent generates a predictive production schedule taking into account manufacturing requirements and local constraints using tabu search. The predictive schedule is modified so as to minimise deviation between the performance measure values

D. Quelhadj; Peter I. Cowling; Sanja Petrovic

2003-01-01

82

Cutting forces in turning of gray cast iron using silicon nitride based cutting tool  

Microsoft Academic Search

This paper presents the results of an experimental investigation about the effect of cutting forces on gray cast iron turning using silicon nitride (Si3N4) based ceramic tool. Turning experiments were carried out at five different cutting speeds and feed rates while depth of cut was kept constant. Tool performance was evaluated with respect to tool wear, temperature, surface finish produced

J. V. C. Souza; M. C. A. Nono; M. V. Ribeiro; J. P. B. Machado; O. M. M. Silva

2009-01-01

83

Thermally induced grinding damage in cast equiaxed nickel-based superalloys  

Microsoft Academic Search

The overall objective of this program was to increase the understanding and productivity of conventional grinding operations utilized in the finishing of cast equiaxed nickel-based superalloy components. To achieve this overall goal a four phase approach was employed. Initially, a grinding energy partition relationship for conventional grinding of superalloys was developed. Secondly, the mechanisms and conditions that influence superalloy microcracking

Kovach

1986-01-01

84

Corrosion mechanisms of low porosity ZrO 2 based materials during near net shape steel casting  

Microsoft Academic Search

One of the most promising refractory materials for application in near net shape steel casting technologies is zirconia. The corrosion resistance of zirconia based materials in contact with steel and aggressive high casting speed powders has been investigated in a specially designed device simulating operating conditions; the corrosion mechanisms have been illustrated.

C. G Aneziris; E. M Pfaff; H. R Maier

2000-01-01

85

Soft magnetic properties of bulk Fe-based amorphous alloys prepared by copper mold casting  

Microsoft Academic Search

Fe-based amorphous alloys in Fe-(Al,Ga)-(P,B,C,Si) system were found to exhibit a wide supercooled liquid region exceeding 50 K before crystallization. The high stability of the supercooled liquid enabled the production of cylindrical bulk amorphous alloys with diameters up to 2 mm by copper mold casting. The Fe-based bulk amorphous alloys exhibit ferromagnetism with the Curie temperature of about 600 K.

Akihisa Inoue; Akira Takeuchi; Tao Zhang; Akira Murakami; Akihiro Makino

1996-01-01

86

Moving through the phase diagram: morphology formation in solution cast polymer-fullerene blend films for organic solar cells.  

PubMed

The efficiency of organic bulk heterojunction solar cells strongly depends on the multiscale morphology of the interpenetrating polymer-fullerene network. Understanding the molecular assembly and the identification of influencing parameters is essential for a systematic optimization of such devices. Here, we investigate the molecular ordering during the drying of doctor-bladed polymer-fullerene blends on PEDOT:PSS-coated substrates simultaneously using in situ grazing incidence X-ray diffraction (GIXD) and laser reflectometry. In the process of blend crystallization, we observe the nucleation of well-aligned P3HT crystallites in edge-on orientation at the interface at the instant when P3HT solubility is crossed. A comparison of the real-time GIXD study at ternary blends with the binary phase diagrams of the drying blend film gives evidence of strong polymer-fullerene interactions that impede the crystal growth of PCBM, resulting in the aggregation of PCBM in the final drying stage. A systematic dependence of the film roughness on the drying time after crossing P3HT solubility has been shown. The highest efficiencies have been observed for slow drying at low temperatures which showed the strongest P3HT interchain ?-?-ordering along the substrate surface. By adding the "unfriendly" solvent cyclohexanone to a chlorobenzene solution of P3HT:PCBM, the solubility can be crossed prior to the drying process. Such solutions exhibit randomly orientated crystalline structures in the freshly cast film which results in a large crystalline orientation distribution in the dry film that has been shown to be beneficial for solar cell performance. PMID:22004659

Schmidt-Hansberg, Benjamin; Sanyal, Monamie; Klein, Michael F G; Pfaff, Marina; Schnabel, Natalie; Jaiser, Stefan; Vorobiev, Alexei; Müller, Erich; Colsmann, Alexander; Scharfer, Philip; Gerthsen, Dagmar; Lemmer, Uli; Barrena, Esther; Schabel, Wilhelm

2011-11-22

87

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

NASA Astrophysics Data System (ADS)

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

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

2007-11-01

88

Evaluation of an improved centrifugal casting machine.  

PubMed

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

Donovan, T E; White, L E

1985-05-01

89

Modification of the microstructural and physical properties of konjac glucomannan-based films by alkali and sodium carboxymethylcellulose  

Microsoft Academic Search

Edible films were cast from konjac glucomannan (KGM) solutions, with or without added alkali (KOH) and\\/or sodium carboxymethylcellulose (CMC). Four types of KGM-based films (KGM, KGM–KOH, KGM–CMC and KGM–CMC–KOH) were produced and characterized by scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD), moisture sorption, water vapour permeability (WVP), and tensile tests. Tensile properties were studied as a function of water

L. H. Cheng; A. Abd Karim; M. H. Norziah; C. C. Seow

2002-01-01

90

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

NASA Astrophysics Data System (ADS)

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

Klepac, Damir; Š?etar, Mario; Baranovi?, Goran; Gali?, Kata; Vali?, Sre?ko

2014-04-01

91

49 CFR 173.183 - Nitrocellulose base film.  

Code of Federal Regulations, 2011 CFR

...2011-10-01 2011-10-01 false Nitrocellulose base film. 173.183 Section 173.183 Transportation ...Class 1 and Class 7 § 173.183 Nitrocellulose base film. Films, nitrocellulose base, must be packaged in...

2011-10-01

92

49 CFR 173.183 - Nitrocellulose base film.  

Code of Federal Regulations, 2014 CFR

...2014-10-01 2014-10-01 false Nitrocellulose base film. 173.183 Section 173.183 Transportation ...Class 1 and Class 7 § 173.183 Nitrocellulose base film. Films, nitrocellulose base, must be packaged in...

2014-10-01

93

49 CFR 173.183 - Nitrocellulose base film.  

Code of Federal Regulations, 2013 CFR

...2013-10-01 2013-10-01 false Nitrocellulose base film. 173.183 Section 173.183 Transportation ...Class 1 and Class 7 § 173.183 Nitrocellulose base film. Films, nitrocellulose base, must be packaged in...

2013-10-01

94

49 CFR 173.183 - Nitrocellulose base film.  

Code of Federal Regulations, 2010 CFR

...2010-10-01 2010-10-01 false Nitrocellulose base film. 173.183 Section 173.183 Transportation ...Class 1 and Class 7 § 173.183 Nitrocellulose base film. Films, nitrocellulose base, must be packaged in...

2010-10-01

95

49 CFR 173.183 - Nitrocellulose base film.  

Code of Federal Regulations, 2012 CFR

...2012-10-01 2012-10-01 false Nitrocellulose base film. 173.183 Section 173.183 Transportation ...Class 1 and Class 7 § 173.183 Nitrocellulose base film. Films, nitrocellulose base, must be packaged in...

2012-10-01

96

Effect of strain rate on damage evolution in a cast Al-Si-Mg base alloy  

Microsoft Academic Search

An important aspect of damage evolution in cast Al-Si-Mg base alloys is fracture\\/cracking of Si particles. This microstructural\\u000a damage is quantitatively characterized as a function of strain rate in the range 10?4 to 3.7 10+3, at an approximately constant uniaxial compressive strain level (20 to 25 pct). It is shown that the fraction of damaged\\u000a silicon particles, their average size,

Manish D. Dighe; Arun M. Gokhale; Mark F. Horstemeyer; D. A. Mosher

2000-01-01

97

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

PubMed

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

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

2015-05-01

98

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

99

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

PubMed

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

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

2014-04-01

100

-Based Mold Flux Used for High Al-TRIP Steel Casting  

NASA Astrophysics Data System (ADS)

An investigation was carried out to study the effect of MnO on crystallization, melting, and heat transfer of lime-alumina-based mold flux used for high Al-TRIP steel casting, through applying the infrared emitter technique (IET) and the double hot thermocouple technique (DHTT). The results of IET tests showed that MnO could improve the general heat transfer rate through promoting the melting and inhibiting the crystallization of mold flux; meanwhile the radiative heat flux was being attenuated. DHTT experiments indicated that the crystallization fraction, melting temperature of mold flux decreased with the addition of MnO. The results of this study can further elucidate the properties of the CaO-Al2O3 slag system and reinforce the basis for the application of lime-alumina system mold fluxes for casting high Al steels.

Zhao, Huan; Wang, Wanlin; Zhou, Lejun; Lu, Boxun; Kang, Youn-Bae

2014-08-01

101

Project CAST.  

ERIC Educational Resources Information Center

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…

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

102

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

PubMed

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

Wu, Feng; Peng, Xiulian; Xu, Jizheng

2014-03-01

103

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

E-print Network

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

Boyer, Edmond

104

A new shell casting process based on expendable pattern with vacuum and low-pressure casting for aluminum and magnesium alloys  

Microsoft Academic Search

A new shell casting process, with the adoption of the foam pattern of lost foam casting (LFC) as prototype and the combination\\u000a of the thin shell fabrication technology of investment casting and vacuum and low-pressure casting process, was proposed for\\u000a manufacturing complicated and thin-walled aluminum and magnesium alloy precision castings. Loose-sand uniting vacuum was used\\u000a in the new process to

Wenming Jiang; Zitian Fan; Defeng Liao; Xuanpu Dong; Zhong Zhao

2010-01-01

105

Structure and properties of nanocomposite films based on sodium caseinate and nanocellulose fibers  

Microsoft Academic Search

Films made from sodium caseinate and nanocellulose were prepared by dispersing the fibrils into film forming solutions, casting and drying. Composite films were less transparent and had a more hydrophilic surface than neat sodium caseinate ones. However, the global moisture uptake was almost not affected by filler concentration. Addition of nanocellulose to the neat sodium caseinate films produced an initial

Mariana Pereda; Guillermina Amica; Ilona Rácz; Norma E. Marcovich

106

Investigation on the dissolution of ? phase in a cast Ni-based superalloy  

NASA Astrophysics Data System (ADS)

The dissolution behavior of ? phase has been investigated in a cast Ni-based superalloy. The results showed that the platelets and blocks of ? phase were formed within the interdendritic regions of the microstructure. Applying standard solution annealing at 1150-1160°C for a period of 4 h did not result in the complete dissolution of ? phase. For the complete dissolution of ? phase without residual incipient melting, a 2-step solution annealing has been recommended. After dissolution at high temperatures, the ? phase transforms to two MC-type carbides: one is enriched in Ti, Nb, and Ta, and the other is of (Zr,Ti)C type.

Jahangiri, M. R.; Arabi, H.; Boutorabi, S. M. A.

2013-01-01

107

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)

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.

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

2012-08-01

108

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

E-print Network

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

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

2010-01-01

109

Plasmonic films based on colloidal lithography.  

PubMed

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

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

2014-04-01

110

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

NASA Astrophysics Data System (ADS)

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

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

2003-07-01

111

Thermally induced grinding damage in cast equiaxed nickel-based superalloys  

SciTech Connect

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

Kovach, J.A.

1986-01-01

112

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

PubMed

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

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

2014-04-01

113

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

PubMed

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

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

2012-12-01

114

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

NASA Astrophysics Data System (ADS)

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

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

2011-08-01

115

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

SciTech Connect

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.

Nagaswaran, R.; Limaye, S.Y.

1996-02-01

116

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

PubMed

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

Okamura, H

1978-10-01

117

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...

118

Microstructural and mechanical properties of nickel-base plasma sprayed coatings on steel and cast iron substrates  

Microsoft Academic Search

This paper studies the phase composition, microstructure, hardness and wear resistance of nickel-base plasma sprayed coatings, on two types of substrates, steel and cast iron. The processing method of metal and compound powders for plasma spraying is detailed, together with the characteristics of the powders before and after processing. It has been found that in as-coated condition, the surface layers

H. Skulev; S. Malinov; W. Sha; P. A. M. Basheer

2005-01-01

119

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

Microsoft Academic Search

In our previous works, metal injection technique into small diameter (10 -100micrometers ) through holes was developed and applied for fabrication of Si based print circuit board. In the present work, we present the metal filling technology by vacuum casting into 3 dimensional through holes and trenches structure fabricated in stacked layered Si wafers prepared by fusion bonding of ICP

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

2001-01-01

120

Properties and cyclic fatigue of glass infiltrated tape cast alumina cores produced using a water-based solvent  

Microsoft Academic Search

ObjectiveThe purpose of this study was to investigate the properties of tape cast alumina composite produced using a water-based solvent and its possible clinical use as an all ceramic crown system in a fixed partial denture. Durability of the system will be measured by fatigue test to simulate the masticating conditions of the oral cavity.

Nam-Sik Oh; Dae-Joon Kim; Joo L. Ong; Ho-Young Lee; Keun-Woo Lee

2007-01-01

121

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...

122

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

PubMed

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

Decherchi, Sergio; Rocchia, Walter

2013-01-01

123

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

PubMed

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

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

2014-06-01

124

A Comparative Study on Microgap of Premade Abutments and Abutments Cast in Base Metal Alloys.  

PubMed

Abstract ABSTRACTThe study compared the marginal accuracy of pre-made 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 < 0.001) were found among all other groups. PMID:22486420

J L, Jaini; Mallan, Sreekanth A; P A, Murukan; Zarina, Rita

2012-04-01

125

Dimensional changes of one-piece frameworks cast from titanium, base metal, or noble metal alloys and supported on telescopic crowns  

Microsoft Academic Search

Statement of problem. The dimensional accuracy of 1-piece frameworks cast from commercially pure titanium and used to accommodate supporting telescopic crowns has not been demonstrated. Purpose. To compare dimensional changes incurred in frameworks cast from commercially pure titanium, a cobalt-chromium alloy, and a noble metal (gold) alloy. Material and Methods. This study was based on 2 different models, both prepared

Matthias Gebelein; Gert Richter; Ursula Range; Bernd Reitemeier

2003-01-01

126

-Based Mold Flux and Their Effects on In-Mold Performance during High-Aluminum TRIP Steels Continuous Casting  

NASA Astrophysics Data System (ADS)

Crystallization behaviors of the newly developed lime-alumina-based mold fluxes for high-aluminum transformation induced plasticity (TRIP) steels casting were experimentally studied, and compared with those of lime-silica-based mold fluxes. The effects of mold flux crystallization characteristics on heat transfer and lubrication performance in casting high-Al TRIP steels were also evaluated. The results show that the crystallization temperatures of lime-alumina-based mold fluxes are much lower than those of lime-silica-based mold fluxes. Increasing B2O3 addition suppresses the crystallization of lime-alumina-based mold fluxes, while Na2O exhibits an opposite effect. In continuous cooling of lime-alumina-based mold fluxes with high B2O3 contents and a CaO/Al2O3 ratio of 3.3, faceted cuspidine precipitates first, followed by needle-like CaO·B2O3 or 9CaO·3B2O3·CaF2. In lime-alumina-based mold flux with low B2O3 content (5.4 mass pct) and a CaO/Al2O3 ratio of 1.2, the formation of fine CaF2 takes place first, followed by blocky interconnected CaO·2Al2O3 as the dominant crystalline phase, and rod-like 2CaO·B2O3 precipitates at lower temperature during continuous cooling of the mold flux. In B2O3-free mold flux, blocky interconnected 3CaO·Al2O3 precipitates after CaF2 and 3CaO·2SiO2 formation, and takes up almost the whole crystalline fraction. The casting trials show that the mold heat transfer rate significantly decreases near the meniscus during the continuous casting using lime-alumina-mold fluxes with higher crystallinity, which brings a great reduction of surface depressions on cast slabs. However, excessive crystallinity of mold flux causes poor lubrication between mold and solidifying steel shell, which induces various defects such as drag marks on cast slab. Among the studied mold fluxes, lime-alumina-based mold fluxes with higher B2O3 contents and a CaO/Al2O3 ratio of 3.3 show comparatively improved performance.

Shi, Cheng-Bin; Seo, Myung-Duk; Cho, Jung-Wook; Kim, Seon-Hyo

2014-06-01

127

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

SciTech Connect

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

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

1995-05-01

128

Development of a freckle predictor via rayleigh number method for single-crystal nickel-base superalloy castings  

Microsoft Academic Search

A Rayleigh number based criterion is developed for predicting the formation of freckles in Ni-base superalloy castings. This\\u000a criterion relies on finding the maximum local Rayleigh number in the mush, where the ratio of the driving buoyancy force to\\u000a the retarding frictional force is the largest. A critical Rayleigh number for freckle formation of approximately 0.25 is found\\u000a from available

C. Beckermann; J. P. Gu; W. J. Boettinger

2000-01-01

129

Cast forsterite concretes for the bases of tunnel-kiln cars  

Microsoft Academic Search

Conclusions We developed a new type of refractory for casting forsterite concretes using a bond made of sodium polyphosphate which has adequate strength after drying, a low coefficient of thermal expansion, and a low thermal conductivity.

L. B. Khoroshavin; V. I. Popova; A. A. Muratov; A. Ya. Nikiforov; Zh. A. Vydrina; E. A. Visloguzova; S. A. Khlynov

1979-01-01

130

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

NASA Astrophysics Data System (ADS)

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

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

2004-02-01

131

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

NASA Astrophysics Data System (ADS)

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.

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

2005-07-01

132

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

PubMed

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

Sadegh-Hassani, Fatemeh; Mohammadi Nafchi, Abdorreza

2014-06-01

133

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

PubMed

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

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

2014-01-30

134

Real-Time, Model-Based Spray-Cooling Control System for Steel Continuous Casting  

NASA Astrophysics Data System (ADS)

This article presents a new system to control secondary cooling water sprays in continuous casting of thin steel slabs (CONONLINE). It uses real-time numerical simulation of heat transfer and solidification within the strand as a software sensor in place of unreliable temperature measurements. The one-dimensional finite-difference model, CON1D, is adapted to create the real-time predictor of the slab temperature and solidification state. During operation, the model is updated with data collected by the caster automation systems. A decentralized controller configuration based on a bank of proportional-integral controllers with antiwindup is developed to maintain the shell surface-temperature profile at a desired set point. A new method of set-point generation is proposed to account for measured mold heat flux variations. A user-friendly monitor visualizes the results and accepts set-point changes from the caster operator. Example simulations demonstrate how a significantly better shell surface-temperature control is achieved.

Petrus, Bryan; Zheng, Kai; Zhou, X.; Thomas, Brian G.; Bentsman, Joseph

2011-02-01

135

Preparation and Characterization of Anode-Supported YSZ Thin Film Electrolyte by Co-Tape Casting and Co-Sintering Process  

NASA Astrophysics Data System (ADS)

In this study, a co-tape casting and co-sintering process has been developed to prepare yttria-stabilized zirconia (YSZ) electrolyte films supported on Ni-YSZ anode substrates in order to substantially reduce the fabrication cost of solid oxide fuel cells (SOFC). Through proper control of the process, the anode/electrolyte bilayer structures with a size of 7.8cm × 7.8cm were achieved with good flatness. Scanning electron microscopy (SEM) observation indicated that the YSZ electrolyte film was about 16 ?m in thickness, highly dense, crack free and well-bonded to the anode support. The electrochemical properties of the prepared anode-supported electrolyte film was evaluated in a button cell mode incorporating a (LaSr)MnO3-YSZ composite cathode. With humidified hydrogen as the fuel and stationary air as the oxidant, the cell demonstrated an open-circuit voltage of 1.081 V and a maximum power density of 1.01 W/cm2 at 800°C. The obtained results represent the important progress in the development of anode-supported intermediate temperature SOFC with reduced fabrication cost.

Liu, Q. L.; Fu, C. J.; Chan, S. H.; Pasciak, G.

2011-06-01

136

A Physically Based Numerical Color Calibration Algorithm for Film  

E-print Network

in animation film production is the discrepancy between the color seen on a cinema screen and the originalA Physically Based Numerical Color Calibration Algorithm for Film Alan Edelman # Frank Wang + Arun reproduction using film. We demonstrate that color reproduc­ tion is a natural application of the Non

Edelman, Alan

137

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

SciTech Connect

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

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

1996-12-01

138

Creep crack growth behavior at 1033K of directionally solidified CM 247 LC — a cast nickel-base superalloy  

Microsoft Academic Search

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

M. S. Gopala Krishna; A. M. Sriramamurthy; V. M. Radhakrishnan

1996-01-01

139

[Flow of molten metal in denture base in horizontal centrifugal casting procedure. (Part 1) Flow, inflow volume and casting time of molten metal passing through single aprue into disk type mold (author's transl)].  

PubMed

A pyrex glass plate was fitted at the bottom of casting ring, and disk type wax pattern (thickness. 0.43 mm) was put on the plate. Five types of sprueing were applied. Pure tin was casted using holizontal centrifugal casting machine. Flow of molten metal was filmed by the motor drive camera with the method of stroboscope. The results were summarized as follows. 1) When the sprue was attached at the center of the disk type mold vertically, moten metal flowed like a concentric circle at the early stage of casting. It was affected gradually by the direction of gravity and revolution, and it filled the mold from the lower part to the upper part. 2) When the sprue gate was attached to the side edge of the mold, and the sprue gate was placed to the forward and backward direction against the revolution direction, molten metal filled from lower part to the upper part. 3) When the sprue gate was placed against upper edge, molten metal flow was affected by the direction of gravity and revolution. When the sprue gate was placed against lower edge, molten metal filled quietry from the lower part to the upper part. 4) Inflow volume per unit time (inflow rate) was small at the early stage of casting. Inflow rate increased and became constant at the next stage. At the latter stage it became small again. 5) Inflow rate increased with the increase of area of sprue. 6) The time which was necessary to fill the volume of 1 cm (about 80% of the mold volume) became short with the increase of area of sprue. It was also influenced by the type of sprueing. PMID:772141

Okamura, H

1976-01-01

140

Starch-based Antimicrobial Films Incorporated with Lauric Acid and Chitosan  

NASA Astrophysics Data System (ADS)

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.

Salleh, E.; Muhamad, I. I.

2010-03-01

141

Polyox and carrageenan based composite film dressing containing anti-microbial and anti-inflammatory drugs for effective wound healing.  

PubMed

Polyethylene oxide (Polyox) and carrageenan based solvent cast films have been formulated as dressings for drug delivery to wounds. Films plasticised with glycerol were loaded with streptomycin (30%, w/w) and diclofenac (10%, w/w) for enhanced healing effects in chronic wounds. Blank and drug loaded films were characterised by texture analysis (for mechanical and mucoadhesive properties), scanning electron microscopy, differential scanning calorimetry, X-ray diffraction and Fourier transform infrared spectroscopy. In addition, swelling, in vitro drug release and antibacterial studies were conducted to further characterise the films. Both blank and drug loaded films showed a smooth, homogeneous surface morphology, excellent transparency, high elasticity and acceptable tensile (mechanical) properties. The drug loaded films showed a high capacity to absorb simulated wound fluid and significant mucoadhesion force which is expected to allow effective adherence to and protection of the wound. The films showed controlled release of both streptomycin and diclofenac for 72 h. These drug loaded films produced higher zones of inhibition against Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli compared to the individual drugs zones of inhibition. Incorporation of streptomycin can prevent and treat chronic wound infections whereas diclofenac can target the inflammatory phase of wound healing to relieve pain and swelling. PMID:23228898

Boateng, Joshua S; Pawar, Harshavardhan V; Tetteh, John

2013-01-30

142

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

SciTech Connect

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.

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

2010-07-15

143

[The collector system of the kidney. Applied anatomy based on the analysis of 3-dimensional casts].  

PubMed

The kidney collector system were studied in 120 three-dimensional casts obtained by the injection-corrosion method. To the procurement of the first hundred casts, we made use of a polyester resin; however on the preparation of the last twenty we made use of a mixture containing latex and radiographic contrast as we intended to obtain, besides the casts, the roentgenograms. Two anatomic details, which have a great importance for endourology, were observed: a. the calices' cross draining the meso-renal region and the consequent inter-pelvis-calice (space (IPC) formation which is seen in the roentgenograms, b. a smaller calice which penetrates perpendicularly the surface of the renal pelvis or into the surface of a great calice. The urologists must appreciate these two anatomic structures, before the surgical procedures on the collector system. PMID:3680967

Sampaio, F J; Mandarim-De-Lacerda, C A; De Aragão, A H

1987-01-01

144

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

SciTech Connect

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.

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

2014-09-30

145

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

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.

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

2009-01-01

146

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

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.

Fasoyinu, Yemi [CanmetMATERIALS] [CanmetMATERIALS; Griffin, John A. [University of Alabama - Birmingham] [University of Alabama - Birmingham

2014-03-31

147

Clean Metal Casting  

SciTech Connect

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.

Makhlouf M. Makhlouf; Diran Apelian

2002-02-05

148

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...

149

Fabrication of integral ceramic mold for investment casting of hollow turbine blade based on stereolithography  

Microsoft Academic Search

Purpose – The purpose of this paper is to develop a novel process of integral ceramic molds for investment casting of hollow turbine blades. Design\\/methodology\\/approach – At first, a resin pattern of a hollow turbine blade prototype is fabricated by stereolithography (SL). And then aqueous gelcasting process is utilized to fill the resin pattern with ceramic slurry of low viscosity

Haihua Wu; Dichen Li; Nannan Guo

2009-01-01

150

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...

151

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

NASA Astrophysics Data System (ADS)

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

Dhakal, Tara; Ganta, Lakshmi; Westgate, Charles

2012-02-01

152

The use of fluidized sand bed as an innovative technique for heat treating aluminum based castings  

NASA Astrophysics Data System (ADS)

The current study was carried out to arrive at a better understanding of the influences of the fluidized sand bed heat treatment on the tensile properties and quality indices of A356.2 and B319.2 casting alloys. For the purposes of validating the use of fluidized sand bed furnaces in industrial applications for heat treatment of 356 and 319 castings, the tensile properties and the quality indices of these alloys were correlated with the most common metallurgical parameters, such as strontium modification, grain refining, solutionizing time, aging parameters and quenching media. Traditional heat treatment technology, employing circulating air convection furnaces, was used to establish a relevant comparison with fluidized sand beds for the heat treatment of the alloys investigated, employing T6 continuous aging cycles or multi-temperature aging cycles. Quality charts were used to predict and/or select the best heat treatment conditions and techniques to be applied in industry in order to obtain the optimum properties required for particular engineering applications. The results revealed that the strength values achieved in T6-tempered 319 and 356 alloys are more responsive to fluidized bed (FB) heat treatment than to conventional convection furnace (CF) treatment for solution treatment times of up to 8 hours. Beyond this solution time, no noticeable difference in properties is observed with the two techniques. A significant increase in strength is observed in the FB heat-treated samples after short aging times of 0.5 and 1 hour, the trend continuing up to 5 hours. The 319 alloys show signs of overaging after 8 hours of aging using a conventional furnace, whereas with a fluidized bed, overaging occurs after 12 hours. Analysis of the tensile properties in terms of quality index charts showed that both modified and non-modified 319 and 356 alloys display the same, or better, quality, after only a 2-hr treatment in an FB compared to 10 hours when using a CF. The quality values of the 356 alloys are more responsive to the FB technique than 319 alloys through long aging times of up to 5 hours. The 319 alloys heat-treated in an FB, however, show better quality values after 0.5 hour of aging and for solution treatment times of up to 5 hours than those treated using a CF. With regard to the quality charts of 319 alloys, heat-treated samples show that increasing the aging time up to peak-strength, i.e. 8 and 12 hours in a CF and an FB, respectively, results in increasing in the alloy strength with a decrease in the quality values, for each of the solution heat treatment times used. The statistical analysis of the results reveals that modification and heating rate of the heat treatment technique have the greatest positive effects on the quality values of the 356 alloys. The use of a fluidized sand bed for the direct quenching-aging treatment of A356.2 and B319.2 casting alloys yields greater UTS and YS values compared to conventional furnace quenched alloys. The strength values of T6 tempered A356 and B319 alloys are greater when quenched in water compared to those quenched in an FB or CF. For the same aging conditions (170°C/4h), the fluidized bed quenched-aged 319 and 356 alloys show nearly the same or better strength values than those quenched in water and then aged in a CF or an FB. Based on the quality charts developed for alloys subjected to different quenching media, higher quality index values are obtained by water-quenched T6-tempered A356 alloys, and conventional furnace quenched-aged T6-tempered B319 alloys, respectively. The modification factor has the most significant effect on the quality results of the alloys investigated, for all heat treatment cycles, as compared to other metallurgical parameters. The results of alloys subjected to multi-temperature aging cycles reveal that the strength results obtained after the T6 continuous aging treatment of A356 alloys are not improved by means of multi-temperature aging cycles, indicating therefore that the optimum properties are obtained using a T6 aging treatment. The optimu

Ragab, Khaled

153

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

SciTech Connect

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.

Gupta, Surbhi; Gupta, Vinay, E-mail: drguptavinay@gmail.com [Department of Physics and Astrophysics, University of Delhi, Delhi (India); Tomar, Monika [Department of Physics, Miranda Housea, University of Delhi, Delhi (India); James, A. R. [Defence Metallurgical Research Laboratory, Hyderabad (India); Pal, Madhuparna; Guo, Ruyan; Bhalla, Amar [Department of Electrical and Computer Engineering, College of Engineering, University of Texas at SanAntonio, San Antonio 78249 (United States)

2014-06-21

154

Crystallinity in cast Nafion  

SciTech Connect

The performance of a polymer electrolyte fuel cell is critically dependent on the water uptake in the polymer electrolyte, usually Nafion. Nafion in solution is often painted onto the electrodes of the fuel cell. It is important that this cast Nafion film stay amorphous and not crystallize. Cast Nafion films, ca. 1 {micro}m thick, crystallized on silicon plates when kept in air at room temperature for a long time. The films contain large crystalline regions ranging from 0.5 mm to several millimeters in size. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) microspectroscopy have been used to investigate the crystalline and amorphous regions. The XRD shows two sharp peaks. One of the peaks is developed before the second one appears in the diffractogram, indicating that there might be two types of crystallizing processes. FTIR spectra of the amorphous and crystalline regions in the films show important differences. In the crystalline regions, the film contains the sulfonic acid at the end of the side chains; hence, the crystalline regions contain no water molecules. In the amorphous regions there is a complete proton transfer from the acid to the water molecules, and sulfonate groups are obtained.

Ludvigsson, M.; Lindgren, J.; Tegenfeldt, J.

2000-04-01

155

Pd-based films produced by PECVD for optical recording  

NASA Astrophysics Data System (ADS)

Plasma enhanced chemical vapor deposition is a novel process to produce metal-filled polymer films. Both bis-allyl-Pd-Cl and allyl-Pd-pentacyclodienyl precursors were used. In conditions dependent on precursor, pressure, electrical power, voltage, frequency and substrate temperature films of different chemical structure and morphology were obtained. Transparent films and absorptive amorphous ones were deposited. Film structure could be both mixture of particles and Pd particles surrounded by organic matrix. The complicated structure of organic part of Pd-based films can be explained by some chemical syntheses taking place during plasma process. The film sensitivity to laser irradiation and writing threshold dependent not only on Pd content but also on phases distribution morphology. Film sensitivity correlates with its electrical resistivity. Thermal stability correlates with cross-links quantity. Pd particles were not oxidized under 450 degrees C annealing.

Gritsenko, Konstantin P.

1996-08-01

156

Spray cast Al-Si base alloys for stiffness and fatigue strength requirements  

Microsoft Academic Search

SUMMARY Hypereutectic AlSiFe spray-cast alloys exhibit properties similar to those of metal-matrix composite (MMC's) : high Young's modulus and a low coefficient of thermal expansion. These physical properties can be adjusted by changing the Si content of the alloy. The refinement of the microstructure is produced by formation of a large amount of nuclei in the spray. Consolidation done by

M. COURBIERE; A. MOCELLIN

1993-01-01

157

Carbon nanotube based nanostructured thin films: preparation and application  

NASA Astrophysics Data System (ADS)

Hybrid thin films of multi-walled carbon nanotube (MWCNT) and titania were fabricated on quartz slides by alternatively depositing MWCNT and titanium(IV) bis(ammonium lactato) dihydroxide (TALH) via a solution based layer-by-layer (LbL) self-assembly method followed by calcination to convert TALH to crystalline titania. The multilayer film build-up was monitored by UV-vis spectroscopy which indicated the linear growth of the film with the bilayer number. XRD confirmed the formation of anantase titania after heat treatment. The photocatalytic property of the hybrid thin film was evaluated by its capacity to degrade rhodamine B under the UV illumination. Compared with pure TiO2 film, experiments showed that the MWCNT/TiO2 hybrid film had a much higher photocatalytic activity under the same conditions. The first order rate constant of photocatalysis of 30 bilayers of hybrid film was approximately 8-fold higher than that of 30 bilayers of pure TiO2 film. In addition, the degradation efficiency of MWCNT/TiO2 hybrid thin film increased with its thickness while pure titania film remained unchanged. A 30 bilayers hybrid thin film that contains about 0.2 mg MWCNT/TiO2 catalyst was capable of completely degrading 10 mL of 2 mg/L Rh B solution within 5 hours. The results also indicated that the hybrid catalyst could be reused for several cycles.

Fu, Li; Yu, Aimin

2013-08-01

158

Integrated thick-film nanostructures based on spinel ceramics  

PubMed Central

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

2014-01-01

159

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

Microsoft Academic Search

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

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

2008-01-01

160

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

PubMed

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

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

2004-10-20

161

Electrocaloric devices based on thini-film heat switches  

SciTech Connect

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.

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

2009-01-01

162

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...

163

Perfect subwavelength fishnetlike metamaterial-based film terahertz absorbers  

Microsoft Academic Search

We present two different designs of robust, easily manufactured metamaterial-based films of subwavelength thickness capable of full absorption of incident terahertz radiation at certain frequencies. Both designs allow a choice between the total absorption of all polarizations or only one linear polarization while the other polarization is reflected. Even if the films are optimized for normal incidence, the absorption remains

D. Yu. Shchegolkov; A. K. Azad; J. F. O'Hara; E. I. Simakov

2010-01-01

164

[The kidney collecting system in man: systematization and morphometry based on 100 polyester resin casts].  

PubMed

This study was made on 100 polyester casts of human rena cavities. Four morphological types were founded on the basis of the superior, middle and inferior great calices drainage. Types AI and AII showed two great calices, types BI and BII showed an independent middle drainage. The number of small calices were not statistically correlationed to number of great calices and morphometrical renal data. The inter-pelvis-calices space was described (IPC, type AII) as well as the pelvis perpendicular small calice. PMID:3916326

Sampaio, F J; Mandarim-de-Lacerda, C A

1985-12-01

165

Cast Awayand the Contradictions of Product Placement  

Microsoft Academic Search

This essay looks at implications of product placement in Cast Away, the 2000 film in which Tom Hanks plays a Federal Express executive who is stranded on a desert island before making his way back home. It argues that Cast Awayis a particularly valuable case study because of the conflict between its relentless product placement and its dark vision of

Ted Friedman

2004-01-01

166

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

NASA Technical Reports Server (NTRS)

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.

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

167

Chimerical categories: caste, race, and genetics.  

PubMed

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

Sabir, Sharjeel

2003-12-01

168

A Hierarchical Fuzzy Model for Predicting Casting Time in a Slip-Casting Process Kimberly L. Petri and Alice E. Smith  

E-print Network

A Hierarchical Fuzzy Model for Predicting Casting Time in a Slip-Casting Process Kimberly L. Petri Abstract This paper outlines the development of a predictive model for the casting time in a ceramic slip-casting, and one that predicts casting time based on the casting rate of the slip and the condition of the mold

Smith, Alice E.

169

Processing and characterization of extruded zein-based biodegradable films  

NASA Astrophysics Data System (ADS)

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

Wang, Ying

170

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

PubMed

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

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

2014-01-01

171

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

172

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

Microsoft Academic Search

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

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

2011-01-01

173

Porphyrin-based honeycomb films and their antibacterial activity.  

PubMed

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

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

2014-06-10

174

p-channel thin-film transistors based on spray-coated Cu2O films  

NASA Astrophysics Data System (ADS)

Thin films of cuprous oxide (Cu2O) were grown using solution-based spray pyrolysis in ambient air and incorporated into hole-transporting thin-film transistors. The phase of the oxide was confirmed by X-ray diffraction measurements while the optical band gap of the films was determined to be ˜2.57 eV from optical transmission measurements. Electrical characterization of Cu2O films was performed using bottom-gate, bottom-contact transistors based on SiO2 gate dielectric and gold source-drain electrodes. As-prepared devices show clear p-channel operation with field-effect hole mobilities in the range of 10-4-10-3 cm2 V-1 s-1 with some devices exhibiting values close to 1 × 10-2 cm2 V-1 s-1.

Pattanasattayavong, Pichaya; Thomas, Stuart; Adamopoulos, George; McLachlan, Martyn A.; Anthopoulos, Thomas D.

2013-04-01

175

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

SciTech Connect

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.

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

2006-04-15

176

Preparation, characterization and in vitro evaluation of a polyvinyl alcohol/sodium alginate based orodispersible film containing sildenafil citrate.  

PubMed

In this work, we developed a sildenafil citrate (SC)-loaded polyvinyl alcohol (PVA)/sodium alginate (ALG-Na) based orodispersible film (ODF) using a solvent casting method. Formulation factors such as the type and amount of plasticizers and disintegrants were optimized on the basis of characteristics of blank ODF, including the disintegration time, elastic modulus (EM) and percentage of elongation (E%). SC-loaded ODF with a loading capacity up to 25 mg in an area of 6 cm2 was prepared and evaluated in terms of mechanical properties, disintegration time and dissolution rate. The surface morphology of ODF was visualized under a scanning electron microscope (SEM). The physicochemical properties of ODF were investigated using X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). The blank ODF composed of PVA, polyethylene glycol 400 (PEG 400) and ALG-Na (20:5:2, w/w) had a remarkably short disintegration time of about 20 s. However, the loading of drug extended the disintegration time (100 s) of ODF, while it still maintained satisfactory mechanical properties. SC was homogenously dispersed throughout the films and the crystalline form of drug changed, with strong hydrogen bonding between the drug and carriers. The PVA/ALG-Na based ODF containing SC prepared by the simple solvent casting method might be an alternative to conventional SC tablets for the treatment of male erectile dysfunction. PMID:24855822

Shi, Li-Li; Xu, Wei-Juan; Cao, Qing-Ri; Yang, Mingshi; Cui, Jing-Hao

2014-05-01

177

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

PubMed

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

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

1981-05-01

178

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

PubMed

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

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

2013-08-01

179

High-temperature superconducting thin-film-based electronic devices  

SciTech Connect

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.

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

1996-09-01

180

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

Microsoft Academic Search

An efficient process is developed by spin-coating a single-component, self-assembled monolayer (SAM) to simultaneously modify the bottom-contact electrode and dielectric surfaces of organic thin-film transistors (OTFTs). This efficient interface modification is achieved using n-alkyl phosphonic acid based SAMs to prime silver bottom-contacts and hafnium oxide (HfOâ) dielectrics in low-voltage OTFTs. Surface characterization using near edge X-ray absorption fine structure (NEXAFS)

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

2011-01-01

181

Gating of Permanent Molds for ALuminum Casting  

SciTech Connect

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.

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

2004-03-30

182

Energy Consumption of Die Casting Operations  

SciTech Connect

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.

Jerald Brevick; clark Mount-Campbell; Carroll Mobley

2004-03-15

183

Casting methods  

DOEpatents

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.

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

2012-12-18

184

Tensile deformation-induced phase transformation in cast Zn-Al-based alloy (ZnAl{sub 7}Cu{sub 3})  

SciTech Connect

Tensile deformation-induced phase transformation and microstructural changes in a cast Zn-Al-based alloy (ZnAl{sub 7}Cu{sub 3}) were studied, using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The microstructure of the cast alloy and various parts of the tensile tested specimens were detected. Two types of precipitates ({alpha}- and T'-phases) were observed in the Zn-rich phases, {eta}'{sub T} and {epsilon}, respectively. External tensile stress-induced phase transformation and microstructural changes were discussed. The fracture mechanism of the tensile deformed alloy was also discussed.

Zhu, Y.H.; Lee, W.B.; To, S

2003-11-26

185

Volume ray casting is based on sampling the data along sight rays. In this technique, reconstruction is achieved by a convolution,  

E-print Network

ABSTRACT Volume ray casting is based on sampling the data along sight rays. In this technique meth- ods such as early ray termination and bounding volumes, which are methods that traditional voxel volume rendering has emerged as a major technology in many visualization scenarios. A natural choice

Mueller, Klaus

186

Functionally graded alumina-based thin film systems  

DOEpatents

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.

Moore, John J.; Zhong, Dalong

2006-08-29

187

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

Code of Federal Regulations, 2014 CFR

...nitrocellulose-base and cellulose-acetate base film? 1237.30 Section 1237.30 Parks...nitrocellulose-base and cellulose-acetate base film? (a) The nitrocellulose base, a...Agencies must handle nitrocellulose-base film (used in the manufacture of sheet...

2014-07-01

188

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

Code of Federal Regulations, 2013 CFR

...nitrocellulose-base and cellulose-acetate base film? 1237.30 Section 1237.30 Parks...nitrocellulose-base and cellulose-acetate base film? (a) The nitrocellulose base, a...Agencies must handle nitrocellulose-base film (used in the manufacture of sheet...

2013-07-01

189

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

Code of Federal Regulations, 2012 CFR

...nitrocellulose-base and cellulose-acetate base film? 1237.30 Section 1237.30 Parks...nitrocellulose-base and cellulose-acetate base film? (a) The nitrocellulose base, a...Agencies must handle nitrocellulose-base film (used in the manufacture of sheet...

2012-07-01

190

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

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

191

Film-based pressure-sensitive-paint measurements.  

PubMed

A technique to measure surface pressure distributions by use of pressure-sensitive paint and a novel filmbased imaging system is described. An oxygen-permeable photoluminescent paint is excited by narrow-band light centered at 455 nm. The resulting red-shifted luminescence (>570 nm) is imaged with a 35-mm film camera and digitized with a film scanner. The luminescence is quenched by oxygen, resulting in a logarithmic relationship between film density and pressure. An image collected at a reference condition is subtracted from an image obtained at the test condition and calibrated with known pressures. The resulting images are, to our knowledge, the first quantitative global surface measurements made with pressure-sensitive paint by a film-based imaging technique. PMID:19881805

Abbitt, J D; Fuentes, C A; Carroll, B F

1996-11-15

192

A film pressure sensor based on optical fiber Bragg grating  

NASA Astrophysics Data System (ADS)

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

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

2010-03-01

193

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

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

194

Clamshell Casting! Stefanie Wuhrer  

E-print Network

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

Wuhrer, Stefanie

195

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

PubMed

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

Kakei, Yusuke; Shimada, Yukihisa

2015-01-01

196

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

Code of Federal Regulations, 2011 CFR

...manage records on nitrocellulose-base and cellulose-acetate base film? 1237.30 Section...manage records on nitrocellulose-base and cellulose-acetate base film? (a) The...base). (b) Agencies must inspect cellulose-acetate film periodically for...

2011-07-01

197

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

Code of Federal Regulations, 2010 CFR

...manage records on nitrocellulose-base and cellulose-acetate base film? 1237.30 Section...manage records on nitrocellulose-base and cellulose-acetate base film? (a) The...base). (b) Agencies must inspect cellulose-acetate film periodically for...

2010-07-01

198

Casting materials  

DOEpatents

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.

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

199

An interfacial instability in a transient wetting layer leads to lateral phase separation in thin spin-cast polymer-blend films.  

PubMed

Spin-coating is a very widely used technique for making uniform thin polymer films. For example, the active layers in most experimental semiconducting polymer-based devices, such as light-emitting diodes and photovoltaics, are made this way. The efficiency of such devices can be improved by using blends of polymers; these phase separate during the spin-coating process, creating the complex morphology that leads to performance improvements. We have used time-resolved small-angle light scattering and light reflectivity during the spin-coating process to study the development of structure directly. Our results provide evidence that a blend of two polymers first undergoes vertical stratification; the interface between the stratified layers then becomes unstable, leading to the final phase-separated thin film. This has given us the basis for establishing a full mechanistic understanding of the development of morphology in thin mixed polymer films, allowing a route to the rational design of processing conditions so as to achieve desirable morphologies by self-assembly. PMID:16142241

Heriot, Sasha Y; Jones, Richard A L

2005-10-01

200

SemCast: Semantic Multicast for Content-based Data Dissemination  

Microsoft Academic Search

We address the problem of content-based dissemination of highly-distributed, high-volume data streams for stream-based monitoring applications and large-scale data delivery. Existing content-based dissemination approaches commonly rely on distributed filtering trees that require filtering at all brokers on the tree. We present a new semantic multicast approach that eliminates the need for content-based filtering at interior brokers and facilitates fine-grained control

Olga Papaemmanouil; Ugur Çetintemel

2005-01-01

201

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

PubMed

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

Mahajan, Hitendra S; Deshmukh, Sachin R

2015-05-20

202

Initial solidification phenomena: Factors affecting heat transfer in strip casting  

NASA Astrophysics Data System (ADS)

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

Nolli, Paolo

203

Outdoor degradation of thin film amorphous silicon based PV modules  

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

204

Evolution of aluminide coating microstructure on nickel-base cast superalloy CM247 in a single-step high-activity aluminizing process  

Microsoft Academic Search

This study deals with the aluminizing of a directionally cast Ni-base superalloy, namely CM-247, by a single-step process\\u000a using a high-activity pack. It is observed that significant incorporation of Al into the substrate surface during aluminizing\\u000a continues over a period of about 1 hour and is not restricted merely to the first few minutes, as reported in the literature.\\u000a Based

D. K. Das; S. V. Joshi; Vakil Singh

1998-01-01

205

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

PubMed Central

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

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

2011-01-01

206

Optical antennas based on coupled nanoholes in thin metal films  

E-print Network

ARTICLES Optical antennas based on coupled nanoholes in thin metal films Y. ALAVERDYAN* , B. SEP, which makes the nanohole chains effectively behave as linear wire antennas. The possibility to control in areas such as integrated nanophotonic circuits6 , optical antennas7,8 , spectroscopy9 , sensing10

Loss, Daniel

207

Photon heterostructures based on single-crystal opal films  

Microsoft Academic Search

Creation of photon film crystals based on opal structures is a very urgent problem being investigated by several research teams in Russia, Europe, and the United States. We develop an original approach for solving this problem [1?3] on the basis on the properties of nanocrystallization in suspensions of monodisperse spherical silica particles (MSSPs) [4?8]. There are two different methods for

D. V. Kalinin; A. I. Plekhanov; V. V. Serdobintseva; V. F. Shabanov

2007-01-01

208

Wireless micro biomimetic swimming robot based on giant magnetostrictive films  

Microsoft Academic Search

A micro biomimetic swimming robot based on giant magnetostrictive thin film (GMF) actuator is developed. Its working principle is to convert magnetic energy into mechanical vibration of its GMF actuator on the action of piezomagnetism and magneto mechanical coupling of its micro GMF when oscillating magnetic field with different frequencies is externally applied, thereafter propulsive force on robot is generated

Yongshun Zhang; Guangjun Liu

2005-01-01

209

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

NASA Astrophysics Data System (ADS)

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.

Hendel, Robert Ashley

210

Carbon films from polyacrylonitrile  

Microsoft Academic Search

Polyacrylonitrile (PAN) films have been fabricated by both spin and solvent casting techniques, and pyrolyzed to produce carbon films in the thickness range of 200--50 000 A. These films have higher electrical conductivities than carbon films produced from most other precursors at similar temperatures. The chemical structure of the films at different stages of processing was investigated by UV, IR,

C. L. Renschler; A. P. Sylwester; L. V. Salgado

1989-01-01

211

Predicting displacement of augered cast-in-place piles based on load test database  

Microsoft Academic Search

Performance-based design for piles requires the prediction of displacements of piles during loading. In general, such prediction is challenging, given the complexity of load mechanisms, soil profiles and construction effects. This study makes use of the normalized load–displacement behavior of axially loaded piles and develops a probabilistic model for the load–displacement curves based on a load test database. It is

Jianye Ching; Jie-Ru Chen

2010-01-01

212

Ferromagnetism in antiferromagnetic NiO-based thin films  

NASA Astrophysics Data System (ADS)

Polycrystalline NiO-based thin films with Li or/and transition metal ions (V, Cr, Mn, Fe, Co, Cu, Zn) doping have been prepared by a sol-gel spin-coating method. Magnetization measurements reveal that V-, Fe-, and Mn-doped NiO thin films show obvious room-temperature ferromagnetic behaviors and ferromagnetic properties can be enhanced by the Li co-doping. Microstructure and X-ray core-level photoemission spectra analysis indicate that the ferromagnetism was not from the impurity TM metal cluster and may be ascribed to double exchange coupling effects via Li-induced holes.

Lin, Yuan-Hua; Zhan, Bin; Nan, Ce-Wen; Zhao, Rongjuan; Xu, Xiang; Kobayashi, M.

2011-08-01

213

A tunable hybrid metamaterial absorber based on vanadium oxide films  

NASA Astrophysics Data System (ADS)

A tunable hybrid metamaterial absorber (MA) in the microwave band was designed, fabricated and characterized. The hybrid MA was realized by incorporating a VO2 film into the conventional resonant MA. By thermally triggering the insulator-metal phase transition of the VO2 film, the impedance match condition was broken and a deep amplitude modulation of about 63.3% to the electromagnetic wave absorption was achieved. A moderate blue-shift of the resonance frequency was observed which is promising for practical applications. This VO2-based MA exhibits many advantages such as strong tunability, frequency agility, simple fabrication and ease of scaling to the terahertz band.

Wen, Qi-Ye; Zhang, Huai-Wu; Yang, Qing-Hui; Chen, Zhi; Long, Yang; Jing, Yu-Lan; Lin, Yuan; Zhang, Pei-Xin

2012-06-01

214

Dendritic wideband metamaterial absorber based on resistance film  

NASA Astrophysics Data System (ADS)

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

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

2015-03-01

215

Perfect subwavelength fishnetlike metamaterial-based film terahertz absorbers  

NASA Astrophysics Data System (ADS)

We present two different designs of robust, easily manufactured metamaterial-based films of subwavelength thickness capable of full absorption of incident terahertz radiation at certain frequencies. Both designs allow a choice between the total absorption of all polarizations or only one linear polarization while the other polarization is reflected. Even if the films are optimized for normal incidence, the absorption remains greater than 99% for angles up to ˜35° in the TE and up to ˜65° in the TM case. In the first design, the maximum absorption frequency shifts considerably with angle, and in the second design it is independent of angle.

Shchegolkov, D. Yu.; Azad, A. K.; O'Hara, J. F.; Simakov, E. I.

2010-11-01

216

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

PubMed

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 96mm×12mm 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

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

2015-05-01

217

Oxygen and oil barrier properties of microfibrillated cellulose films and coatings  

Microsoft Academic Search

The preparation of carboxymethylated microfibrillated cellulose (MFC) films by dispersion-casting from aqueous dispersions\\u000a and by surface coating on base papers is described. The oxygen permeability of MFC films were studied at different relative\\u000a humidity (RH). At low RH (0%), the MFC films showed very low oxygen permeability as compared with films prepared from plasticized\\u000a starch, whey protein and arabinoxylan and

Christian Aulin; Mikael Gällstedt; Tom Lindström

2010-01-01

218

Prediction of Part Distortion in Die Casting  

SciTech Connect

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.

R. Allen Miller

2005-03-30

219

Engineered pigments based on iridescent cellulose nanocrystal films.  

PubMed

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

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

2015-05-20

220

Tensile Behavior of Fabric Cement-Based Composites: Pultruded and Cast  

E-print Network

. In addition to the ease of manufacturing, fabrics provide benefits such as excellent anchorage and bond strength of only 6­10 MPa. Similar products re- inforced with polyacrylnitril PAN -based carbon continuous . Results of various studies suggest that the manufacturing pro- cess significantly affects the properties

Mobasher, Barzin

221

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

E-print Network

our daily life and has a large social impact through media such as novels, movies, dramas, and games in the existing one. Evaluation results, using an online-game simulator, confirm the effectiveness of the proposed system called OPIATE[1][2] ori- ented to online-games. In OPIATE, a story based on the Propp's morphology

Thawonmas, Ruck

222

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

NASA Astrophysics Data System (ADS)

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

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

223

A domain partitioning based pre-processor for multi-scale modelling of cast aluminium alloys  

Microsoft Academic Search

In this paper, a microstructural morphology based domain partitioning MDP methodology is developed for materials with non-uniform heterogeneous microstructure. The comprehensive set of methods is intended to provide a concurrent multi-scale analysis model with an initial computational domain that delineates regions of statistical homogeneity and inhomogeneity. The MDP methodology is intended to be a pre-processor to multi-scale analysis of mechanical

Somnath Ghosh; D M Valiveti; Stephen J Harris; James Boileau

2006-01-01

224

Thin Wall Iron Castings  

SciTech Connect

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.

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

2001-10-31

225

Metal oxide thin film based supercapacitors  

Microsoft Academic Search

Supercapacitors have been known for over fifty years and are considered as one of the potential energy storage systems. Research into supercapacitors is presently based primarily on their mode of energy storage, namely: (i) the redox electrochemical capacitors and (ii) the electrochemical double layer capacitor. The commonly investigated classes of materials are transition metal oxides (notably, ruthenium oxide) and conducting

C. D. Lokhande; D. P. Dubal; Oh-Shim Joo

2011-01-01

226

Diagnostic accuracy of monoclonal antibody based serum immunoglobulin free light chain immunoassays in myeloma cast nephropathy  

PubMed Central

Background The development of serum immunoassays for the measurement of immunoglobulin free light chains has led to a paradigm shift in the diagnosis, assessment and monitoring of patients with plasma cell dyscrasias. The impact of these immunoassays which employ polyclonal antibodies was most notable for those patients who were previously classified as non-secretory multiple myeloma. Recently new monoclonal antibody based assays have become available. The purpose of this study was to compare the diagnostic sensitivity of these new assays with those already in clinical practice. Methods Sera from 30 patients who present with severe acute kidney injury and multiple myeloma were identified for analysis. A head to head comparison of the two commercially available free light chains assays was then undertaken to determine if their diagnostic sensitivity and specificity were comparable. Results In this first assessment of the utility of these new assays, we found that one of 17 patients with a lambda monoclonal free light chain resulting in acute kidney injury were not identified and a further 12% of patients were wrongly classified as having levels below those associated with disease specific acute kidney injury. Conclusion These results suggest that caution should be applied to the use of new free light chain assays in the assessment of patients with a monoclonal gammopathy. PMID:22873484

2012-01-01

227

Effect of (Mo, W) substitution for Nb on glass forming ability and magnetic properties of Fe–Co-based bulk amorphous alloys fabricated by centrifugal casting  

Microsoft Academic Search

In this study, effects of simultaneous Mo and W substitution for Nb additions on the stability and magnetic properties of Fe–Co-based bulk metallic glass (BMG) alloys fabricated by centrifugal casting are investigated. The saturation magnetization (Js) and coercivity (Hc) for the as-cast Fe36Co36B19.2Si4.8X4 (X=Nb or Mo0.5W0.5) BMG alloys and melt-spun Fe36Co36B19.2Si4.8Mo2W2 were in the range of 1.02–1.57T and 11.13–1685A\\/m, respectively.

Ilker Kucuk; Muratahan Aykol; Orhan Uzun; Mehmet Yildirim; Mehmet Kabaer; Nagehan Duman; Fikret Yilmaz; Kadir Erturk; M. Vedat Akdeniz; Amdulla O. Mekhrabov

2011-01-01

228

Thin film display based on polymer waveguides.  

PubMed

This paper reports thin, transparent, and soft displays based on polymer waveguides that are compliant with curvilinear interfaces. In order to prove a feasibility of optical waveguide for a flexible display, we suggest the waveguide fabricated by a multi-step lithography process using two photo-curable pre-polymers with different refractive index. The displays are composed of light sources, polymer waveguides, and scatter patterns. The light signal propagating through the waveguides forms images of the scatter patterns by deflecting the light signals to outer surface. The scatter patterns are configured to a seven-segment. The seven-segment design with a switching methodology of the light sources contributes to selectively representing all decimal numbers from 0 to 9 by combination of activated segments. For a large area display based on the proposed methodology, a single light source interconnected to multi-waveguide section is integrated with a QWERTY key pad design. The display shows high transparency and flexibility without visual distortion. PMID:25321812

Park, Suntak; Park, Bong Je; Yun, Sungryul; Nam, Saekwang; Park, Seung Koo; Kyung, Ki-Uk

2014-09-22

229

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

PubMed

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

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

2008-09-01

230

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

NASA Astrophysics Data System (ADS)

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.

Naik, Gautam

231

Immunosensor systems with the Langmuir-film-based fluorescence detection  

SciTech Connect

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)

Chudinova, G K; Nagovitsyn, I A; Savranskii, V V [Natural Science Center, A.M. Prokhorov General Physics Institute, Russian Academy of Sciences, Moscow (Russian Federation); Karpov, R E [Photochemistry Center, Russian Academy of Sciences, Moscow (Russian Federation)

2003-09-30

232

Team-based thin-film CIS research activities  

NASA Astrophysics Data System (ADS)

This paper describes the team-based thin-film copper indium diselenide (CIS) research activities. The CIS team was formed in December 1994 in Kona, Hawaii. Originally, the team had two working groups: the "Junction" and the "Absorber" groups. Currently, there are four working groups the Present Junction, New Junction, Substrate/Mo Impact, and the Transient Effect groups. We have completed extensive data compilation of CIS-based films and solar cells using various techniques such as Auger, photoluminescence, scanning electron microscopy, secondary-ion mass spectrometry, X-ray photoelectron spectroscopy, X-ray diffraction, capacitance-voltage, light and dark current-voltage, and quantum efficiency. Studies are under way to understand the fundamental mechanisms that demonstrate a total-area, high efficiency of 17.7% in CuInGaSe2 devices using chemical-bath deposition (CBD) CdS. Alternate buffer layers are also being investigated to replace the CBD CdS. The impact of various Mo substrates from the various industrial partners has been investigated, and the results are reported. A study is under way to investigate the transient effects in encapsulated/laminated thin-film CIS-based devices.

Ullal, Harin S.

1997-02-01

233

Team-based thin-film CIS research activities  

SciTech Connect

This paper describes the team-based thin-film copper indium diselenide (CIS) research activities. The CIS team was formed in December 1994 in Kona, Hawaii. Originally, the team had two working groups: the {open_quotes}Junction{close_quotes} and the {open_quotes}Absorber{close_quotes} groups. Currently, there are four working groups the Present Junction, New Junction, Substrate/Mo Impact, and the Transient Effect groups. We have completed extensive data compilation of CIS-based films and solar cells using various techniques such as Auger, photoluminescence, scanning electron microscopy, secondary-ion mass spectrometry, X-ray photoelectron spectroscopy, X-ray diffraction, capacitance-voltage, light and dark current-voltage, and quantum efficiency. Studies are under way to understand the fundamental mechanisms that demonstrate a total-area, high efficiency of 17.7{percent} in CuInGaSe{sub 2} devices using chemical-bath deposition (CBD) CdS. Alternate buffer layers are also being investigated to replace the CBD CdS. The impact of various Mo substrates from the various industrial partners has been investigated, and the results are reported. A study is under way to investigate the transient effects in encapsulated/laminated thin-film CIS-based devices. {copyright} {ital 1997 American Institute of Physics.}

Ullal, H.S. [National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, Colorado 80401 (United States)

1997-02-01

234

Antimicrobial food packaging film based on the release of LAE from EVOH.  

PubMed

The aim of this work was to develop antimicrobial films for active packaging applications containing the natural antimicrobial compound LAE (lauramide arginine ethyl ester) in EVOH copolymers with different mol % ethylene contents (i.e. EVOH-29 and EVOH-44). EVOH-29 and EVOH-44 films were made by casting and incorporating 0.25%, 1%, 5%, and 10% LAE in the film forming solution (w/w with respect to polymer weight). Previously, the minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) of LAE against Listeria monocytogenes, Escherichia coli, and Salmonella enterica were determined by a microdilution assay. The antimicrobial activity of the resulting films was tested in vitro against these microorganisms in liquid culture media. The activity of the films was also evaluated over time. The results showed that films containing 5% and 10% LAE produced total growth inhibition and viable counts decreased with 0.25% and 1% LAE. Finally, the effectiveness of the films was tested by applying them to an infant formula milk inoculated with L. monocytogenes and S. enterica and stored for 6 days at 4°C. The application of films with LAE to infant formula milk inoculated with L. monocytogenes reduced at the end of storage period about 4 log in case of 10% LAE and with S. enterica reduced 3.74 log and 3.95 log with EVOH 29 5% and 10%, respectively, and EVOH-44 5% and 10% LAE reduced 1 log and 3.27 log, respectively, at the end of storage. The antimicrobial capacity of EVOH-29 films was greater than that of EVOH-44 films in all the cases tested. In general, the films were more effective in inhibiting the growth of L. monocytogenes than S. enterica, this inhibition being more acute at the end of the storage time. PMID:22640726

Muriel-Galet, Virginia; López-Carballo, Gracia; Gavara, Rafael; Hernández-Muñoz, Pilar

2012-07-01

235

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

SciTech Connect

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.

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

2007-01-01

236

Initial solidification phenomena: Factors affecting heat transfer in strip casting  

Microsoft Academic Search

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

Paolo Nolli

2007-01-01

237

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

PubMed

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

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

2014-10-01

238

Piezoelectric micromachined ultrasonic transducers based on PZT thin films.  

PubMed

This paper describes fabrication and characterization results of piezoelectric micromachined ultrasonic transducers (pMUTs) based on 2-microm-thick Pb(Zr0.53Ti0.47O3) (PZT) thin films. The applied structures are circular plates held at four bridges, thus partially unclamped. A simple analytical model for the fully clamped structure is used as a reference to optimize design parameters such as thickness relations and electrodes, and to provide approximate predictions for coupling coefficients related to previously determined thin film properties. The best coupling coefficient was achieved with a 270-microm plate and amounted to kappa2 = 5.3%. This value compares well with the calculated value based on measured small signal dielectric (epsilon = 1050) and piezoelectric (e3l,f = 15 Cm(-2)) properties of the PZT thin film at 100 kV/cm dc bias. The resonances show relatively large Q-factors, which can be partially explained by the small diameters as compared to the sound wavelength in air and in the test liquid (Fluorinert 77). A transmit-receive experiment with two quasi-identical pMUTs was performed showing significant signal transmission up to a distance of 20 cm in air and 2 cm in the test liquid. PMID:16463493

Muralt, Paul; Ledermann, Nicolas; Baborowski, Jacek; Barzegar, Abdolghaffar; Gentil, Sandrine; Belgacem, Brahim; Petitgrand, Sylvain; Bosseboeuf, Alain; Setter, Nava

2005-12-01

239

MEMS-based thin-film fuel cells  

DOEpatents

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.

Jankowksi, Alan F.; Morse, Jeffrey D.

2003-10-28

240

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

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

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

241

Thermal properties of fish myofibrillar protein-based films as affected by moisture content  

Microsoft Academic Search

Myofibrilar protein-based films were developed from a film-forming solution based on fish mince. The thermal properties of these films were characterized by dynamical mechanical thermal analysis and by differential scanning calorimetry as a function of their water content. During a temperature increase, the films produced sudden changes in mechanical property and specific heat, which are classicaly associated with the glass-rubber

Bernard Cuq; Nathalie Gontard; Stéphane Guilbert

1997-01-01

242

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...

243

Large displacement vertical translational actuator based on piezoelectric thin films  

PubMed Central

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

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

2014-01-01

244

Naphthacene Based Organic Thin Film Transistor With Rare Earth Oxide  

SciTech Connect

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

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

2010-12-01

245

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

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

Jei, J Brintha; Mohan, Jayashree

2014-03-01

246

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

SciTech Connect

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

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

2011-12-31

247

Effect of casting methods on accuracy of peridental restorations.  

PubMed

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

Finger, W; Kota, K

1982-06-01

248

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

NASA Astrophysics Data System (ADS)

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

Jeon, Yu Hong

249

Development of Advanced Coating Techniques for Highly-durable Casting Dies  

NASA Astrophysics Data System (ADS)

In order to improve the durability of aluminum die-casting molds, we applied microstructure-controlled PVD coating techniques. Single-layer and multilayer films consisting of chromium nitride (CrN) or titanium aluminum nitride (TiAlN) were prepared using an ion plating process. Structures of multilayer films were observed using transmission electron microscopy. Pin-shaped mold steel specimens coated with each of the films were soaked in the molten aluminum alloy at 953 K different periods of time, and the amount of weight loss due to erosion was evaluated. The weight losses for the multilayer CrN and TiAlN specimens were found to be less than those for the single-layer specimens. As a practical test, five specimens of core pins used in aluminum die casting of automobile parts were coated with multilayer films, and the number of maintenance operations required to remove aluminum alloy remaining on the specimen surfaces after several thousand castings was counted and compared with six control specimens (core pins treated using a commercial salt bath diffusion process). The number of maintenance operations for CrN- and TiAlN-based multilayer-coated core pins was found to be lower than for the control specimens.

Tanaka, S.; Takagi, M.; Mano, T.

2013-03-01

250

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

NASA Astrophysics Data System (ADS)

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.

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

2011-10-01

251

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

SciTech Connect

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.

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

2006-06-30

252

Roll Casting of Aluminum Alloy Clad Strip  

Microsoft Academic Search

Casting of aluminum alloy three layers of clad strip was tried using the two sets of twin roll casters, and effects of the casting parameters on the cladding conditions were investigated. One twin roll caster was mounted on the other twin roll caster. Base strip was 8079 aluminum alloy and overlay strips were 6022 aluminum alloy. Effects of roll-load of

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

2011-01-01

253

Porous mullite composite with controlled pore structure processed using a freeze casting of TBA-based coal fly ash slurries  

Microsoft Academic Search

Porous ceramic composite with controlled “designer” pore structure has been prepared by a freeze casting route using a tertiary-butyl alcohol (TBA)\\/coal fly slurry system. Unidirectional aligned macropore channels were developed by controlling the solidification direction. Simultaneously, small sized dendrite-like pores formed in the outer walls of the pore channels. The compressive strength of the sintered porous composite increased as the

T. Y. Yang; H. B. Ji; S. Y. Yoon; B. K. Kim; H. C. Park

2010-01-01

254

A study of Ni 3Si-based composite coating fabricated by self-propagating high temperature synthesis casting route  

Microsoft Academic Search

A Ni3Si–Cr7C3 composite coating was fabricated on AISI 1020 steel substrate by self-propagating high-temperature synthesis (SHS) casting route. Phase composition, microhardness and dry sliding wear behavior of the coating were studied. The results indicated that the coating was mainly consisted of Ni3Si and Cr7C3. The microhardness of coating is about 900HV. The friction and wear tests showed that although the

Muye Niu; Qinling Bi; Lingqian Kong; Jun Yang; Weimin Liu

2011-01-01

255

Yield Improvement in Steel Casting (Yield II)  

SciTech Connect

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

Richard A. Hardin; Christoph Beckermann; Tim Hays

2002-02-18

256

Egyptian Caste System  

NSDL National Science Digital Library

Understand the culture, character, and societal characteristics of different classes in the ancient Egyptian caste system Understand the culture, character, and societal characteristics of different classes in the ancient Egyptian caste system Go to these sites to learn about the Egyptian Caste System ...

Ms. Issen

2009-09-17

257

Casting and Molding  

NSDL National Science Digital Library

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

Perkins School for the Blind

2012-06-26

258

Megahertz-frequency large-area optical modulators at 1.55 m based on solution-cast  

E-print Network

. Talapin and C. B. Murray, "PbSe nanocrystal solidsforn-andp-channel thin film field. Fritz, "Electro-otic properties of CdS embedded in a polymer," Phys. Rev. B 48, 11979-11986 (1993). 10 and electrochromic response of semiconductor nanocrystal thin films," J. Phys. Chem. B 107, 7355-7359 (2003). 15. W

259

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

NASA Astrophysics Data System (ADS)

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

Lu, Boxun; Wang, Wanlin

2015-01-01

260

Solution-cast films of poly(3,4-ethylenedioxythiophene) as ion-to-electron transducers in all-solid-state ion-selective electrodes  

Microsoft Academic Search

An aqueous dispersion of poly(3,4-ethylenedioxythiophene) (PEDOT) doped with poly(styrenesulfonate) (PSS) was cast on screen-printed gold substrates. PEDOT(PSS) was ionically (physically) crosslinked by multivalent cations, including Mg2+, Ca2+, Fe2+\\/3+ and Ru(NH3)62+\\/3+ to form a hydrogel in order to decrease the water solubility of the PEDOT(PSS). The resulting Au\\/PEDOT(PSS) electrodes were characterized by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and energy-dispersive

Mercedes Vázquez; Petter Danielsson; Johan Bobacka; Andrzej Lewenstam; Ari Ivaska

2004-01-01

261

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

PubMed

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

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

2014-03-01

262

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

NASA Technical Reports Server (NTRS)

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

Freche, John C; Schum, Eugene F

1957-01-01

263

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)

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.

Cooper, R. A.

1976-01-01

264

Use of REM-Based Modifying Agents for Improving the Structure and Properties of Cast Tungsten-Molybdenum High-Speed Steels  

Microsoft Academic Search

Special features of the structure and properties of cast high-speed steels R6M5K5 and R6M5 modified by REM-based additives, i.e., ferrocerium in a design amount of 0.1, 0.3, 0.6, and 1.2% and silicomishmetal and alumoyttrium in a design amount of 0.1, 0.3, and 0.6% are studied. Results of metallographic, x-ray diffraction, fracture surface, and microscopic x-ray spectral analyses of the steels

A. S. Chaus

2004-01-01

265

Sensors and Actuators B 49 (1998) 258267 Pd/PVDF thin film hydrogen sensor based on  

E-print Network

Sensors and Actuators B 49 (1998) 258­267 Pd/PVDF thin film hydrogen sensor based on laser thin film coated on a polymeric membrane, optical reflectance and transmittance signals are generated polyvinilydene fluoride (PVDF) thin-film photopy- roelectric (PPE) sensors [1,2]. The PPE sensor exhibits

Mandelis, Andreas

266

Acid-Base Equilibria of Weak Polyelectrolytes in Multilayer Thin Films  

E-print Network

Acid-Base Equilibria of Weak Polyelectrolytes in Multilayer Thin Films Susan E. Burke) incorporated in polyelectrolyte multilayer thin films. We assembled 10 polyelectrolyte layers on colloidal,4 The stratified structure of polyelectrolyte multilayer films has also been combined with small molecules

Barrett, Christopher

267

Suitability of some fluoropolymers used as base films for preparation of polymer electrolyte fuel cell membranes  

Microsoft Academic Search

Radiation grafting is a well-established technique for the preparation of polymer electrolyte membranes for fuel cells. The nature of the base films is an important parameter which is in close relation to the properties of the fuel cell membranes. In this study, six commercially available fluoropolymer films, PTFE, FEP, PFA, ETFE, PVDF and PVF films, together with the crosslinked PTFE

Jinhua Chen; Masaharu Asano; Yasunari Maekawa; Masaru Yoshida

2006-01-01

268

Photopolymerization-based fabrication of chemical sensing films  

DOEpatents

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

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

2003-12-30

269

Amperometric uric acid sensors based on polyelectrolyte multilayer films  

Microsoft Academic Search

Uricase (UOx) and polyelectrolyte were used for preparation of a permselective multilayer film and enzyme multilayer films on a platinum (Pt) electrode, allowing the detection of uric acid amperometrically. The polyelectrolyte multilayer (PEM) film composed of poly(allylamine) (PAA) and poly(vinyl sulfate) (PVS) were prepared via layer-by-layer assembly on the electrode, functioning as H2O2-selective film. After deposition of the permselective film

Tomonori Hoshi; Hidekazu Saiki; Jun-ichi Anzai

2003-01-01

270

Marginal reservoirs for multiunit castings.  

PubMed

This study measured the distortion of one-piece base metal four-unit fixed partial dentures and recorded the effect of positioning "marginal reservoirs" on the wax patterns. Standard wax patterns were made in a special three-piece stainless steel mold. Twenty anterior prostheses were cast: 10 for the experimental group and 10 for the control group. The prostheses were cast in a nickel-chromium alloy and were measured with a traveling microscope with a micrometer scale. Premarked points were designated on gingivoaxial line angles for buccolingual and mesiodistal distances and diameters to record marginal discrepancies of specimens with or without marginal reservoirs. Castings with marginal reservoirs distorted significantly less than did the control fixed partial dentures. PMID:7568745

Omurtay, S; Aslan, Y

1995-04-01

271

Magnesium-lithium casting alloys  

NASA Technical Reports Server (NTRS)

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

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

1974-01-01

272

Beam casting implicit surfaces on the GPU with interval arithmetic  

E-print Network

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

273

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

PubMed

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

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

2012-12-12

274

Fabrication of graphene-based films using remote plasma CVD  

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

275

Gating of Permanent Molds for Aluminum Casting  

SciTech Connect

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

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

2004-01-01

276

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

277

Design of novel miconazole nitrate transdermal films based on Eudragit RS100 and HPMC hybrids: preparation, physical characterization, in vitro and ex vivo studies.  

PubMed

Abstract The objective of this study was to formulate and evaluate transdermal films containing miconazole nitrate (MN), a poorly water-soluble imidazole antifungal agent, with a view to enhancing its delivery across intact skin. Transdermal films of MN were formulated by solvent casting technique using admixtures of film-forming polymers - Eudragit RS100 and hydroxypropylmethylcellulose (HPMC) (2:8, 4:6, 5:5, 6:4 and 8:2) with polyethylene glycol 8000 (plasticizer and permeation enhancer) and Tween 80 (mobile surfactant). The films were evaluated for weight uniformity, folding endurance, thickness, moisture loss and uptake, bioadhesive strength, drug content, skin irritation on rabbits and time-resolved stability. The ex vivo release of MN from the films was carried out using a modified Franz diffusion apparatus while the microbiological evaluation was conducted using a clinical isolate of Candida albicans. Overall results indicate that films made with two portions of Eudragit RS100 and eight portions of HPMC (batch T-1) had the least weight variation (57.33?±?0.27?mg), folding endurance (307.90?±?4.17), moisture uptake (1.37?±?0.28%) and thickness (145.9?±?2.08?µm), but highest drug content (97.50?±?2.43%) and bioadhesive strength (81.40?±?2.03?dyne/cm(2)), best bioactivity and in vitro skin permeation through rat skin with highest permeation flux (5.161?µg/cm(2)?h) and permeation coefficient (1.032?×?10(-6?)cm/h) compared to all other formulations. This study has established that transdermal films based on 2:8 admixtures of Eudragit RS100 and HPMC could offer a promising approach for the treatment of skin infections caused by MN-susceptible fungi. PMID:24455998

Ofokansi, Kenneth C; Kenechukwu, Franklin C; Ogwu, Nkechi N

2014-01-23

278

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

PubMed

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

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

2014-11-01

279

Property evaluations of dry-cast reconstituted bacterial cellulose/tamarind xyloglucan biocomposites.  

PubMed

We describe the mechanical defibrillation of bacterial cellulose (BC) followed by the dry-cast generation of reconstituted BC films (RBC). Xyloglucan (XGT), extracted from tamarind seeds, was incorporated into the defibrillated cellulose at various compositions, and new films were created using the same process. Microscopy and contact angle analyses of films revealed an increase in the microfibre adhesion, a reduced polydispersity in the diameters of the microfibrils and increased hydrophobic behaviour as a function of %XGT. X-ray diffraction analysis revealed changes to the crystallographic planes of the RBC and the biocomposite films with preferential orientation along the (110) plane. Compared with BC, RBC/XGT biocomposite with 10% XGT exhibited improvement in its thermal properties and in Young's modulus. These results indicated a reorganisation of the microfibres with mechanical treatment, which when combined with hydrocolloids, can create cellulose-based materials that could be applied as scaffolding for tissue engineering and drug release. PMID:23465913

de Souza, Clayton F; Lucyszyn, Neoli; Woehl, Marco A; Riegel-Vidotti, Izabel C; Borsali, Redouane; Sierakowski, Maria Rita

2013-03-01

280

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

PubMed

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

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

2015-03-30

281

Processing of IN-718 Lattice Block Castings  

NASA Technical Reports Server (NTRS)

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.

Hebsur, Mohan G.

2002-01-01

282

Optical corrosion sensor based on fiber Bragg grating electroplated with Fe-C film  

NASA Astrophysics Data System (ADS)

An optical fiber corrosion sensor (OFCS) based on iron-carbon (Fe-C) film was researched. OFCS was formed by electroplating a Fe-C film on fiber Bragg grating (FBG) metalized with silver film by magnetron sputtering. There was a more than 430-pm change of FBG wavelength when Fe-C film was seriously corroded. Compared to electrochemical method, the optical fiber sensor shows dominance in long-lasting monitoring of corrosion. The electric signal was broken off after the 20-h corrosion of Fe-C film, while the optical fiber sensor's monitoring lasted more than 40 days.

Zheng, Xing; Hu, Wenbin; Zhang, Ning; Gao, Min

2014-07-01

283

Graphene-based supercapacitor with carbon nanotube film as highly efficient current collector.  

PubMed

Flexible graphene-based thin film supercapacitors were made using carbon nanotube (CNT) films as current collectors and graphene films as electrodes. The graphene sheets were produced by simple electrochemical exfoliation, while the graphene films with controlled thickness were prepared by vacuum filtration. The solid-state supercapacitor was made by using two graphene/CNT films on plastic substrates to sandwich a thin layer of gelled electrolyte. We found that the thin graphene film with thickness <1 ?m can greatly increase the capacitance. Using only CNT films as electrodes, the device exhibited a capacitance as low as ?0.4 mF cm(-2), whereas by adding a 360 nm thick graphene film to the CNT electrodes led to a ?4.3 mF cm(-2) capacitance. We experimentally demonstrated that the conductive CNT film is equivalent to gold as a current collector while it provides a stronger binding force to the graphene film. Combining the high capacitance of the thin graphene film and the high conductivity of the CNT film, our devices exhibited high energy density (8-14 Wh kg(-1)) and power density (250-450 kW kg(-1)). PMID:25301789

Notarianni, Marco; Liu, Jinzhang; Mirri, Francesca; Pasquali, Matteo; Motta, Nunzio

2014-10-31

284

Graphene-based supercapacitor with carbon nanotube film as highly efficient current collector  

NASA Astrophysics Data System (ADS)

Flexible graphene-based thin film supercapacitors were made using carbon nanotube (CNT) films as current collectors and graphene films as electrodes. The graphene sheets were produced by simple electrochemical exfoliation, while the graphene films with controlled thickness were prepared by vacuum filtration. The solid-state supercapacitor was made by using two graphene/CNT films on plastic substrates to sandwich a thin layer of gelled electrolyte. We found that the thin graphene film with thickness <1 ?m can greatly increase the capacitance. Using only CNT films as electrodes, the device exhibited a capacitance as low as ˜0.4 mF cm?2, whereas by adding a 360 nm thick graphene film to the CNT electrodes led to a ˜4.3 mF cm?2 capacitance. We experimentally demonstrated that the conductive CNT film is equivalent to gold as a current collector while it provides a stronger binding force to the graphene film. Combining the high capacitance of the thin graphene film and the high conductivity of the CNT film, our devices exhibited high energy density (8–14 Wh kg?1) and power density (250–450 kW kg?1).

Notarianni, Marco; Liu, Jinzhang; Mirri, Francesca; Pasquali, Matteo; Motta, Nunzio

2014-10-01

285

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

SciTech Connect

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.

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

1994-06-01

286

Application of zeolite membranes, films and coatings  

Microsoft Academic Search

Preparation methods of zeolite molecular sieve membranes and films with and without support were reviewed. Unsupported films have been prepared by in situ synthesis, casting of zeolite nanoparticles and solid state transformation, and supported films have been obtained by in situ synthesis, vapor-phase synthesis, secondary growth, casting of nanoparticles and their combinations or modifications. It is favorable to use supports

Fujio Mizukami

1999-01-01

287

Evolution of halictine castes  

NASA Astrophysics Data System (ADS)

Social halictine bees have female castes that range from species with no size differences to those with a discrete bimodality. Female caste differences are inversely correlated with the number of males produced in the first brood. It is proposed that the sexual dimorphism of solitary forms is being usurped by the female caste system of species in the process of turning social. Thus, caste differences and summer male suppression are greatest in the social species originating from solitary precursors with distinct sexual dimorphism, and are least in species evolving from solitary ancestors with a continuous sexual polymorphism.

Knerer, Gerd

1980-03-01

288

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

SciTech Connect

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.

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

2013-02-04

289

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

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

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

290

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

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

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

291

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

292

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

Microsoft Academic Search

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

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

2010-01-01

293

Summary of thermal properties for casting alloys and mold materials  

NASA Astrophysics Data System (ADS)

A review of thermal properties of casting alloys and mold materials was conducted for the purpose of stimulating activity in computer aided design for castings. A summary of thermal data; thermal conductivity, specific heat, density, and heats of fusion was prepared for metals and casting alloys, and for primary molding materials. This summary represents an initial step in the development of data bases for support of computer aided design systems for castings. Additional information is required, in particular for thermal properties of commercial casting alloy systems.

Pehlke, R. D.; Jeyarajan, A.; Wada, H.

1982-12-01

294

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

PubMed Central

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

Landová, Hana; Gajdziok, Jan; Doležel, Petr; Muselík, Jan; Dvo?á?ková, Kate?ina; Jekl, Vladimír; Hauptman, Karel

2014-01-01

295

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

296

High-Tc/high-coupling relaxed PZT-based single crystal thin films  

NASA Astrophysics Data System (ADS)

Pb(Zr,Ti)O3 (PZT)-based ferroelectric ceramics exhibit high piezoelectricity, however, their Curie temperature (Tc) values are not so high, i.e., Tc < 400 °C. PZT-based piezoelectric thin films with higher Tc would be beneficial for improved micro actuators, sensors, memories, and piezoelectric micro-electro mechanical systems. In-plane biaxial strained PZT thin films in a laminated composite structure are known to exhibit enhanced Tc; however, the thickness of PZT-based thin films is limited to below a critical thickness typically <50 nm. The Tc of relaxed PZT-based thin films with thicknesses greater than the critical thickness is the same as bulk Tc. However, a sort of relaxed PZT-based single-crystal thin films exhibit extraordinary high Tc, Tc = ˜600 °C. In addition, the films show extremely low dielectric constant, ?/?o ˜ 100 with high coupling factor, kt ˜ 0.7, and large remnant polarization, Pr ˜ 100 ?C/cm2. These exotic properties would result from the single-domain/single-crystal structure. The enhanced Tc is possibly caused by the highly stable interface between the PZT-based thin films and substrates. Their ferroelectric performances are beyond those of conventional PZT. The high-Tc/high-coupling performances are demonstrated, and the possible mechanisms of the high Tc behavior in relaxed PZT-based single-crystal thin films are discussed.

Wasa, K.; Matsushima, T.; Adachi, H.; Matsunaga, T.; Yanagitani, T.; Yamamoto, T.

2015-03-01

297

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

NASA Astrophysics Data System (ADS)

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.

Mushi, Ngesa; Utsel, Simon; Berglund, Lars

2014-11-01

298

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

PubMed Central

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

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

2014-01-01

299

Optical Sensors Based on Single Arm Thin Film Waveguide Interferometer  

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

300

Polyester-based thin films with high photosensitivity  

SciTech Connect

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.

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

2000-02-29

301

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

SciTech Connect

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.

Bramhaiah, K., E-mail: jsneena@csmr.res.in; John, Neena S., E-mail: jsneena@csmr.res.in [Centre for Soft Matter Research, P.B. No.1329, Jalahalli, Bangalore-560013 (India)

2014-04-24

302

Cellulose triacetate, thin film dielectric capacitor  

NASA Technical Reports Server (NTRS)

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.

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

1993-01-01

303

Cellulose triacetate, thin film dielectric capacitor  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

304

Cool Cast Facts  

MedlinePLUS

... A splint can be made from the same materials as a cast or may be a pre-made piece of stiff plastic or metal surrounded by strong fabric. It is like a half cast that's wrapped with an elastic bandage or held in place with Velcro straps. A ...

305

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

PubMed Central

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

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

2009-01-01

306

Mechanical, physicochemical and color properties of chitosan based-films as a function of Aloe vera gel incorporation  

Microsoft Academic Search

The objective of the present study was to investigate the effect of Aloe vera gel incorporation at different proportions on chitosan-based films. Consequently, the thickness of films was affected significantly by the addition of the gel and decreased from F0 (plain chitosan film) to F50 (the film containing 50% gel). The gel incorporation did not have a considerable effect on

Sadegh Khoshgozaran-Abras; Mohammad Hossein Azizi; Zohreh Hamidy; Niloofar Bagheripoor-Fallah

307

Films  

NASA Astrophysics Data System (ADS)

Magnetic thin films of Ta/NiO/Ni81Fe19/NiO/Ta were fabricated by a magnetron sputtering method. The effects of NiO layer thickness and substrate temperature on the anisotropic magnetoresistance (AMR) and the magnetic field sensitivity of these Ni81Fe19 films have been investigated. The results show that the AMR of 20-nm Ni81Fe19 film with 4-nm NiO achieves 5.02% at 450°C, while the magnetic field sensitivity achieves 9.00% × 10-3 m A-1 at the same conditions. These enhanced 40% and 230% comparing with the film without NiO layer, respectively.

Wang, Shuyun; Zhang, Hui; Yao, Yuan

2014-09-01

308

Thin-film chemical sensors based on electron tunneling  

NASA Technical Reports Server (NTRS)

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.

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

1985-01-01

309

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

NASA Astrophysics Data System (ADS)

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

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

2012-08-01

310

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

Microsoft Academic Search

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

Dongxing Yang

2006-01-01

311

Multielectrocatalysis by Layer-by-Layer Films Based on Pararosaniline and Vanadium-Substituted Phosphomolybdate.  

PubMed

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

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

2015-02-10

312

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

Microsoft Academic Search

The fabrication of transparent, conductive, and uniform silver nanowire films using the scalable rod-coating technique is described in this study. Properties of the transparent conductive thin films are investigated, as well as the approaches to improve the performance of transparent silver nanowire electrodes. It is found that silver nanowires are oxidized during the coating process. Incubation in hydrogen chloride (HCl)

Cai-Hong Liu; Xun Yu

2011-01-01

313

CHARACTERIZATION OF CASEIN-BASED FILMS BY TRANSMISSION ELECTRON MICROSCOPY  

Technology Transfer Automated Retrieval System (TEKTRAN)

Edible films, made from milk proteins such as casein, offer a potential alternative to nonbiodegradable coatings and films currently used to enhance the quality or extend the shelf life of foods. Bovine casein obtained by a novel process using high pressure CO2 is of particular interest not only bec...

314

Advanced electrochromic devices based on WO 3 thin films  

Microsoft Academic Search

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

S Papaefthimiou; G Leftheriotis; P Yianoulis

2001-01-01

315

Influence of film growth conditions on carrier mobility of hot wall epitaxially grown fullerene based transistors  

NASA Astrophysics Data System (ADS)

Hot wall epitaxially grown C 60 based organic field-effect transistors (OFETs) show relatively high electron mobilities of 0.4-1 cm 2/Vs. We report results of thin film grown with various growth conditions such as preheating and initial substrate temperatures resulting in strikingly different fullerene film nanomorphology. The mobility is enhanced up to 3 cm 2/Vs for films grown at a substrate temperatures of 130 °C. This improvement in the mobility is explained in terms of a transition from a disordered interface consisting of small-elongated grains to a well-ordered C 60 film with bigger and rounder grains.

Montaigne Ramil, A.; Singh, Th. B.; Haber, N. T.; Marjanovi?, N.; Günes, S.; Andreev, A.; Matt, G. J.; Resel, R.; Sitter, H.; Sariciftci, S.

2006-02-01

316

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

NASA Technical Reports Server (NTRS)

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.

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

1973-01-01

317

Oligocarbazole-based chromophores for efficient thin-film dye-sensitized solar cells.  

PubMed

Carb your enthusiasm: Carbazole-based sensitizers with high extinction coefficients are synthesized for application in dye-sensitized solar cells (DSCs). The dyes perform efficiently with both iodine and cobalt electrolytes, showing power conversion efficiencies of up to 5.8% on TiO? films of 15 ?m thickness, and retaining 90% of their efficiency in devices with thinner films. PMID:23674249

De Sousa, Samuel; Olivier, Céline; Ducasse, Laurent; Le Bourdon, Gwenaëlle; Hirsch, Lionel; Toupance, Thierry

2013-06-01

318

Achromatic circular polarizer in the 482-535 nm range based on polypropylene films  

NASA Astrophysics Data System (ADS)

We present a design for an achromatic circular polarizer based on polypropylene films. The circular polarizer, having eccentricity ?0.92 in the 482-535 nm range and ideally circular for the wavelength of ~505 nm, is obtained by combining BOPP C2-25 and BOPP C2-35 films of thickness 23 m and 33 ?m.

Muravsky, Al. A.; Murauski, An. A.; Agabekov, V. E.; Chuvasheva, O. O.; Ivanova, N. A.

2012-11-01

319

One-dimensional semiconductor nanostructure based thin-film partial composite formed by transfer implantation for high-performance flexible and printable electronics at low temperature.  

PubMed

Having high bending stability and effective gate coupling, the one-dimensional semiconductor nanostructures (ODSNs)-based thin-film partial composite was demonstrated, and its feasibility was confirmed through fabricating the Si NW thin-film partial composite on the poly(4-vinylphenol) (PVP) layer, obtaining uniform and high-performance flexible field-effect transistors (FETs). With the thin-film partial composite optimized by controlling the key steps consisting of the two-dimensional random dispersion on the hydrophilic substrate of ODSNs and the pressure-induced transfer implantation of them into the uncured thin dielectric polymer layer, the multinanowire (NW) FET devices were simply fabricated. As the NW density increases, the on-current of NW FETs increases linearly, implying that uniform NW distribution can be obtained with random directions over the entire region of the substrate despite the simplicity of the drop-casting method. The implantation of NWs by mechanical transfer printing onto the PVP layer enhanced the gate coupling and bending stability. As a result, the enhancements of the field-effect mobility and subthreshold swing and the stable device operation up to a 2.5 mm radius bending situation were achieved without an additional top passivation. PMID:21174391

Moon, Kyeong-Ju; Lee, Tae-Il; Choi, Ji-Hyuk; Jeon, Joohee; Kang, Youn Hee; Kar, Jyoti Prakash; Kang, Jung Han; Yun, Ilgu; Myoung, Jae-Min

2011-01-25

320

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

321

Mechanisms of stabilization of earthworm casts and artificial casts  

Microsoft Academic Search

Fresh casts were collected from the earthworm species Aporrectodea caliginosa, and artificial casts were also made. The casts were subjected to ageing, drying-rewetting, and sterilization by hexanol vapour. Clay dispersion was determined, as a measure of the lack of stability of the casts. Two soils were used, the topsoil of a recently reclaimed polder soil in the Netherlands and the

J. C. Y. Marinissen; A. R. Dexter

1990-01-01

322

Vacuum-vapor-deposited films based on benzo(a)phenoxazine derivatives under surface plasma fluorination  

NASA Astrophysics Data System (ADS)

Modification of vacuum vapor deposited thin films based on benzo(a)phenoxazone-5 derivatives with C3F8 and SF6 plasma were investigated. X-ray photoelectron spectroscopy (XPS) method was used to identify and study the distribution of surface functional groups of untreated and fluorinated films investigated. It was shown that fluor content in element composition of surface film layers and perfluorocarbon group content in Cls-lines of XP-spectra depended on chemical structure of the initial compounds. The more quantity and size of side substitutes were contained in the compound chemical structure the less was the content of fluor and perfluorocarbon groups in film surface fluorinated layer. The probable way of plasma active particle interaction with film surface is discussed. Using Kaelbe's method the influence of treatment conditions and initial compound chemical structure on surface properties of fluorinated films was studied.

Agabekov, Vladimir E.; Ignasheva, Olga E.; Belyatsky, Vladimir N.

1997-07-01

323

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

PubMed

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

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

324

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

PubMed

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

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

2015-02-01

325

Electrophoretically deposited polyaniline nanotubes based film for cholesterol detection.  

PubMed

Polyaniline nanotube (PANI-NT) based films have been fabricated onto indium-tin-oxide (ITO) coated glass plates via electrophoretic technique. These PANI-NT/ITO electrodes have been utilized for covalent immobilization of cholesterol oxidase (ChOx) using glutaraldehyde (Glu) as cross-linker. Structural, morphological and electrochemical characterization of PANI-NT/ITO electrode and ChOx/Glu/PANI-NT/ITO bioelectrode have been done using FT-IR spectroscopy, SEM, electrochemical impedance spectroscopy and cyclic voltammetry techniques. Response studies of the ChOx/Glu/PANI-NT/ITO bioelectrode have been carried out using both linear sweep voltammetry and UV-Visible spectrophotometry. The results of the biosensing studies reveal that this bioelectrode can be used to detect cholesterol in wide detection range of 25-500 mg/dL with high sensitivity of 3.36 mA mg(-1) dL and fast response time of 30 s at pH 7.4. This bioelectrode exhibits very low value of Michaelis-Menten constant of 1.18 mM indicating enhanced interactions between cholesterol and ChOx immobilized onto this nanostructured PANI matrix. PMID:21077243

Dhand, Chetna; Solanki, Pratima R; Pandey, Manoj K; Datta, Monika; Malhotra, Bansi D

2010-11-01

326

Properties of blend film based on cuttlefish (Sepia pharaonis) skin gelatin and mungbean protein isolate.  

PubMed

Blend films based on cuttlefish (Sepia pharaonis) ventral skin gelatin (CG) and mungbean protein isolate (MPI) at different blend ratios (CG/MPI=10:0, 8:2, 6:4, 4:6, 2:8 and 0:10, w/w) prepared at pH 11 using 50% glycerol (based on total protein) as plasticizer were characterized. CG films incorporated with MPI at increasing amounts had the decreases in tensile strength (TS) (p<0.05). The increases in elongation at break (EAB) were observed when CG/MPI ratios of 6:4 or 4:6 were used (p<0.05). Decreased water vapor permeability (WVP) was obtained for films having the increasing proportion of MPI (p<0.05). CG/MPI blend films with higher MPI proportion had lower film solubility and L*-values (lightness) but higher b*-values (yellowness) and ?E*-values (total color difference) (p<0.05). Electrophoretic study revealed that disulfide bond was present in MPI and CG/MPI blend films. However, hydrogen bonds between CG and MPI in the film matrix were dominant, as elucidated from FTIR spectroscopic analysis. Moreover, thermal stability of CG/MPI blend film was improved as compared to that of films from respective single proteins. Differential scanning calorimetry result suggested solid-state morphology of CG/MPI (6:4) blend film that consisted of amorphous phase of partially miscible CG/MPI mixture and the coexisting two different order phases of individual CG and MPI domains. Thus, the incorporation of MPI into gelatin film could improve the properties of resulting blend film, which were governed by CG/MPI ratio. PMID:21762722

Hoque, Md Sazedul; Benjakul, Soottawat; Prodpran, Thummanoon; Songtipya, Ponusa

2011-11-01

327

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

NASA Astrophysics Data System (ADS)

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

Nishizawa, Shingo; Shiratori, Seimei

2012-12-01

328

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

PubMed

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 cm(2) V(-1) s(-1) and on-off ratios of ?10(7) 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 cm(2) V(-1) s(-1) and on-off ratios of up to 10(5). Printed inverters based on the TFTs have been constructed on glass substrates, showing a maximum voltage gain of 112 at a V(dd) of -5 V. This work paves the way for making printable logic circuits for real applications. PMID:23595234

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

2013-05-21

329

Roll Casting of Aluminum Alloy Clad Strip  

NASA Astrophysics Data System (ADS)

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

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

2011-01-01

330

Roll Casting of Aluminum Alloy Clad Strip  

SciTech Connect

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

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

2011-01-17

331

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

NASA Astrophysics Data System (ADS)

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).

Chhabra, M.; Singh, R.

2015-04-01

332

TiNi-based thin films for MEMS applications  

E-print Network

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 ...

Fu, Yongqing

333

Chitosan based edible films and coatings: a review.  

PubMed

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

Elsabee, Maher Z; Abdou, Entsar S

2013-05-01

334

Iron-oxygen-based perpendicular magnetic thin films  

Microsoft Academic Search

Nonstoichiometric FexO1?x and FexMyO1?x?y films, where M is either a nonmagnetic element, e.g., Si, or a magnetic element, e.g., Co, were prepared by sputter deposition. They showed increasing ferromagnetic magnetization with decreasing oxygen concentration below 1?x?y<0.5, and strong perpendicular magnetic anisotropy which overwhelmed the shape anisotropy of the thin ferromagnetic films in certain composition ranges. The magnetization of perpendicular magnetic

T. Mizoguchi; N. Akutsu; M. Akimitsu

1987-01-01

335

A tunable hybrid metamaterial absorber based on vanadium oxide films  

Microsoft Academic Search

A tunable hybrid metamaterial absorber (MA) in the microwave band was designed, fabricated and characterized. The hybrid MA was realized by incorporating a VO2 film into the conventional resonant MA. By thermally triggering the insulator–metal phase transition of the VO2 film, the impedance match condition was broken and a deep amplitude modulation of about 63.3% to the electromagnetic wave absorption

Qi-Ye Wen; Huai-Wu Zhang; Qing-Hui Yang; Zhi Chen; Yang Long; Yu-Lan Jing; Yuan Lin; Pei-Xin Zhang

2012-01-01

336

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

NASA Astrophysics Data System (ADS)

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

Ghafouri, Niloufar

337

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

SciTech Connect

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.

Sabau, Adrian S [ORNL

2005-09-01

338

Method of casting aerogels  

DOEpatents

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.

Poco, J.F.

1993-09-07

339

Method of casting aerogels  

DOEpatents

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.

Poco, John F. (Livermore, CA)

1993-01-01

340

Casting Characteristics of Aluminum Die Casting Alloys  

SciTech Connect

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.

Makhlouf M. Makhlouf; Diran Apelian

2002-02-05

341

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

DOEpatents

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.

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

342

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

E-print Network

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 ...

Smyth, Katherine Marie

2012-01-01

343

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

DOEpatents

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.

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

2014-02-04

344

Surface-Based Assays for Enzyme Adsorption and Activity on Model Cellulose Films  

E-print Network

Cellulose Surfaces by Using Horizontal Dipping Procedure. Applicationand application of surface-based assays for elucidating cellulase kinetics on model films of cellulose.cellulose surface rather than solely with chain ends. Application

Maurer, Samuel Andrew

2012-01-01

345

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

346

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

DOEpatents

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.

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

347

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

PubMed Central

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

Mohamed Saat, Asmalina

2014-01-01

348

Evolution of aluminide coating microstructure on nickel-base cast superalloy CM-247 in a single-step high-activity aluminizing process  

SciTech Connect

This study deals with the aluminizing of a directionally cast Ni-base superalloy, namely CM-247, by a single-step process using a high-activity pack. It is observed that significant incorporation of Al into the substrate surface during aluminizing continues over a period of about 1 hour and is not restricted merely to the first few minutes, as reported in the literature. Based on the microstructural details of the coatings formed at various stages of aluminizing, it is concluded that the coating growth in the above process takes place primarily by inward Al diffusion initially, followed by an intermediate stage when the growth involves both inward Al and outward Ni diffusion. In the final stages, the outward diffusion of Ni dominates the coating formation process. The above mechanism of coating formation is different from the one that prevails in the conventional two-step high-activity coating process in that the reaction front for the formation of NiAl remains spatially stationary despite the outward diffusion of nickel during the intermediate stage. It is also shown in the present study that the content of the Al source in the pack affects the coating structure significantly. It is further demonstrated that the microstructure of the aluminide coatings depends not only on the amount of Al incorporated in the sample during aluminizing but also on the time over which the uptake of this Al takes place.

Das, D.K.; Joshi, S.V. [Defence Metallurgical Research Lab., Hyderabad (India); Singh, V. [Banaras Hindu Univ., Varanasi (India). Dept. of Metallurgical Engineering

1998-08-01

349

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

PubMed

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

Bai, Haicheng; Xie, Zhi; Zhang, Yuzhong; Hu, Zhenwei

2013-06-01

350

Slip casting of partially stabilized zirconia  

SciTech Connect

The toughness of partially-stabilized zirconia has been studied for some time. The tetragonal phase in partially stabilized ZrO2 transforms to the monoclinic phase under the influence of stress. Partially-stabilized ZrO2 has enhanced tensile strength, good wear resistance and low friction coefficient, and has found industrial applications. This article describes the use of partially-stabilized zirconia in slip casting. Lab techniques of slip casting have been reported for nonplastic materials such as Al2O3, CaF2, CaO-stabilized ZrO2 and MgO. The article discusses the variation of slip density and firing temperature and also reports the preparation of specimens of CaOstabilized ZrO2 by slip casting from ethanol-based suspensions. The preparation of Y2O3-ZrO2 compositions by slip casting from aqueous suspension is also reported. A Y2O3 partially stabilized ZrO2 powder was used as a starting material. The densities of the cast specimens were measured from the volume and weight, and those of the sintered specimens were measured by a liquid displacement technique using distilled water. The concentation of the suspension strongly affects the relative density of the cast specimen and the firing shrinkage of the sintered specimen, while the relative density of the sintered specimen is independent of the concentration of the suspension.

Taguchi, H.; Miyamoto, H.; Takahashi, Y.

1985-02-01

351

3D printing technique applied to rapid casting  

Microsoft Academic Search

Purpose – The purpose of this paper is to verify the feasibility and evaluate the dimensional accuracy of two rapid casting (RC) solutions based on 3D printing technology: investment casting starting from 3D-printed starch patterns and the ZCast process for the production of cavities for light-alloys castings. Design\\/methodology\\/approach – Starting from the identification and design of a benchmark, technological prototypes

Elena Bassoli; Andrea Gatto; Luca Iuliano; Maria Grazia Violante

2007-01-01

352

Flexible organic electroluminescent devices based on transparent clay films  

NASA Astrophysics Data System (ADS)

We report the fabrication of flexible organic light-emitting diodes (OLEDs) using transparent clay films with heat-resistant and high-gas-barrier properties. Indium tin oxide (ITO) thin films were deposited as anode layers at high temperature using the rf magnetron sputtering method. The ITO films deposited at temperatures greater than 300 °C exhibit high optical transparency (>90%) in the visible region with a low electrical resistivity of 4 × 10-4 ? cm. Flexible OLEDs with the structure of clay film/ITO/TPD/Alq3/Al (where TPD is N,N'-diphenyl-N,N'-(3-methylphenyl)-[1,1'-biphenyl]-4,4'-diamine and Alq3 is tris(8-hydroxyquinolinato) aluminum) showed a turn-on voltage of around 7.2 V, a luminance efficiency of 2.7 cd A-1, and a luminance of 100 cd m-2 at 11.5 V. Results show that the clay film is an excellent candidate for transparent flexible substrates for use in displays or other electronic applications.

Tetsuka, Hiroyuki; Ebina, Takeo; Tsunoda, Tatsuo; Nanjo, Hiroshi; Mizukami, Fujio

2007-09-01

353

Optimizing the optical and electrical properties of graphene ink thin films by laser-annealing  

NASA Astrophysics Data System (ADS)

We demonstrate a facile fabrication technique for graphene-based transparent conductive films. Highly flat and uniform graphene films are obtained through the incorporation of an efficient laser annealing technique with one-time drop casting of high-concentration graphene ink. The resulting thin films are uniform and exhibit a transparency of more than 85% at 550 nm and a sheet resistance of about 30 k?/?. These values constitute an increase of 45% in transparency, a reduction of surface roughness by a factor of four and a decrease of 70% in sheet resistance compared to un-annealed films.

Khandan Del, Sepideh; Bornemann, Rainer; Bablich, Andreas; Schäfer-Eberwein, Heiko; Li, Jiantong; Kowald, Torsten; Östling, Mikael; Haring Bolívar, Peter; Lemme, Max C.

2015-03-01

354

3D stress simulation and parameter design during twin-roll casting of 304 stainless steel based on the Anand model  

NASA Astrophysics Data System (ADS)

This study first investigated cracks on the surface of an actual steel strip. Formulating the Anand model in ANSYS software, we then simulated the stress field in the molten pool of type 304 stainless steel during the twin-roll casting process. Parameters affecting the stress distribution in the molten pool were analyzed in detail and optimized. After twin-roll casting, a large number of transgranular and intergranular cracks resided on the surface of the thin steel strip, and followed a tortuous path. In the molten pool, stress was enhanced at the exit and at the roller contact positions. The stress at the exit decreased with increasing casting speed and pouring temperature. To ensure high quality of the fabricated strips, the casting speed and pouring temperature should be controlled above 0.7 m/s and 1520°C, respectively.

Guo, Jing; Liu, Yuan-yuan; Liu, Li-gang; Zhang, Yue; Yang, Qing-xiang

2014-07-01

355

Physical Simulation of Investment Casting of Complex Shape Parts  

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

356

Antimicrobial packaging of chicken fillets based on the release of carvacrol from chitosan/cyclodextrin films.  

PubMed

Chitosan/cyclodextrin films (CS:CD) incorporating carvacrol were obtained by casting, and conditioned at 23°C and 75% relative humidity prior to being immersed in liquid carvacrol until they reached sorption equilibrium. In a previous work, the in vitro antimicrobial activity of these films was studied. In this work, active films were used to inhibit microbial growth in packaged chicken breast fillets. Samples of CS:CD films loaded with carvacrol, of different sizes and thus with different quantities of antimicrobial agent, were stuck to the aluminium lid used to seal PP/EVOH/PP cups containing 25g of chicken fillets. These samples were stored for 9days at 4°C. The packages were hermetically sealed and it was confirmed that they provided an infinite barrier to carvacrol. The partition of the antimicrobial agent within the food/packaging system was analysed. The antimicrobial devices rapidly released a large percentage of the agent load, amounts that were gained by the adhesive coating of the lid and especially by the chicken fillets. The latter were the main sorbent phase, with average concentrations ranging between 200 and 5000mg/Kg during the period of storage. The microbiota of the packaged fresh chicken fillets - mesophiles, psychrophiles, Pseudomonas spp., enterobacteria, lactic acid bacteria and yeasts and fungi - were analysed and monitored during storage. A general microbial inhibition was observed, increasing with the size of the active device. Inhibition with a 24cm(2) device ranged from 0.3 log reductions against lactic acid bacteria to 1.8logs against yeasts and fungi. However, the large amount of antimicrobial that was sorbed or that reacted with the fillet caused an unacceptable sensory deterioration. These high sorption values are probably due to a great chemical compatibility between chicken proteins and carvacrol. PMID:25087205

Higueras, Laura; López-Carballo, Gracia; Hernández-Muñoz, Pilar; Catalá, Ramón; Gavara, Rafael

2014-10-01

357

Structural, Electrical and Optical Characterization of Pure and Doped Poly (Vinyl Alcohol) (PVA) Polymer Electrolyte Films  

Microsoft Academic Search

A sodium ion conducting polymer electrolyte based on Poly (Vinyl Alcohol) (PVA) complexed with Sodium Iodide (NaI) was prepared using solution cast technique. The structural properties of composite PVA polymer electrolyte films were examined by XRD. The XRD results revealed that the amorphous domains of PVA polymer matrix increased in size with the increase of NaI salt concentration. The variation

P. Balaji Bhargav; V. Madhu Mohan; A. K. Sharma; V. V. R. N. Rao

2007-01-01

358

Titan Casts Revealing Shadow  

NASA Astrophysics Data System (ADS)

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,

2004-05-01

359

Theoretical investigation of acoustic wave devices based on different piezoelectric films deposited on silicon carbide  

NASA Astrophysics Data System (ADS)

Performances of acoustic wave (AW) devices based on silicon carbide (SiC) substrates are theoretically studied, in which two types of piezoelectric films of ZnO and AlN deposited on 4H-SiC and 3C-SiC substrates are adopted. The phase velocities (PV), electromechanical coupling coefficients (ECC), and temperature coefficients of frequency (TCF) for three AW modes (Rayleigh wave, A0 and S0 modes of Lamb wave) often used in AW devices are calculated based on four types of configurations of interdigital transducers (IDTs). It is found that that the ZnO piezoelectric film is proper for the AW device operating in the low-frequency range because a high ECC can be realized using a thin ZnO film. The AlN piezoelectric film is proper for the device operating in the high-frequency range in virtue of the high PV of AlN, which can increase the finger width of the IDT. Generally, in the low-frequency Lamb wave devices using ZnO piezoelectric films with small normalized thicknesses of films to wavelengths hf/?, thin SiC substrates can increase ECCs but induce high TCFs simultaneously. In the high-frequency device with a large hf/?, the S0 mode of Lamb wave based on the AlN piezoelectric film deposited on a thick SiC substrate exhibits high performances by simultaneously considering the PV, ECC, and TCF.

Fan, Li; Zhang, Shu-yi; Ge, Huan; Zhang, Hui

2013-07-01

360

Crystallographic and optical properties of Mn-substituted II-VI based magnetic semiconductor films  

NASA Astrophysics Data System (ADS)

Building upon the room-temperature magneto-optical properties of ternary and quaternary zinc blende magnetic semiconductor films of CdMnTe, CdMnCoTe, ZnMnTe, and ZnMnSe reported to date, the present study examines the crystallographic and optical properties of Mn-substituted II-VI based magnetic semiconductor films synthesized on sapphire (SA) or quartz glass (QG) substrates by molecular beam epitaxy. CdTe-based films on sapphire or glass exhibited preferential (111) growth as reported previously. However, ZnTe-based films on sapphire showed a (220) growth believed to be induced by the (20bar 22) plane of C-cut hexagonal SA substrates. The influence of crystallinity on optical or magneto-optical properties on both SA and QG is discussed from the viewpoint of the extinction ratio. The extinction ratio of films on QG was low compared to that of films on SA, and decreased further under an applied field. It has been shown that the decrease in the extinction ratio upon the application of a magnetic field contributes to the magneto-optical effect in the films.

Imamura, M.; Yamaguchi, T.

2010-01-01

361

Atomic Oxygen Sensors Based on Nanograin ZnO Films Prepared by Pulse Laser Deposition  

SciTech Connect

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.

Wang Yunfei; Chen Xuekang; Li Zhonghua; Zheng Kuohai; Wang Lanxi; Feng Zhanzu; Yang Shengsheng [National Key Laboratory of Vacuum and Cryogenics Technology and Physics, Lanzhou Institute of Physics, Lanzhou 730000 (China)

2009-01-05

362

Optical fiber-based sensor for in situ monitoring of cadmium sulfide thin-film growth.  

PubMed

This work presents a scheme for in situ monitoring of thin-film growth. A fiber-optic sensor based on Fabry-Perot interferometric technique has been established for the first time to monitor in situ growth of thin films. This was applied for determining thickness of cadmium sulfide (CdS) thin films during growth. The fabrication process of CdS film was carried out in 30 mM cadmium acetate and thioacetamide solution at 60°C temperature. The estimated thickness determined during the growth was verified by scanning electron microscopy. This study shows that in situ measurement of the thickness of thin films is feasible by this new technique, and a close match of the estimated thickness was achieved. PMID:24322264

Karim, Farzia; Bora, Tanujjal; Chaudhari, Mayur B; Habib, Khaled; Mohammed, Waleed S; Dutta, Joydeep

2013-12-15

363

High-energy-density sol-gel thin film based on neat 2-cyanoethyltrimethoxysilane.  

PubMed

Hybrid organic-inorganic sol-gel dielectric thin films from a neat 2-cyanoethyltrimethoxysilane (CNETMS) precursor have been fabricated and their permittivity, dielectric strength, and energy density characterized. CNETMS sol-gel films possess compact, polar cyanoethyl groups and exhibit a relative permittivity of 20 at 1 kHz and breakdown strengths ranging from 650 V/?m to 250 V/?m for film thicknesses of 1.3 to 3.5 ?m. Capacitors based on CNETMS films exhibit extractable energy densities of 7 J/cm(3) at 300 V/?m, as determined by charge-discharge and polarization-electric field measurements, as well as an energy extraction efficiency of ~91%. The large extractable energy resulting from the linear dielectric polarization behavior suggests that CNETMS films are promising sol-gel materials for pulsed power applications. PMID:23427818

Kim, Yunsang; Kathaperumal, Mohanalingam; Smith, O'Neil L; Pan, Ming-Jen; Cai, Ye; Sandhage, Kenneth H; Perry, Joseph W

2013-03-13

364

POLYMERIC ACRYLATE-BASED HYBRID FILMS CONTAINING LEAD AND IRON PATTERNED BY UV PHOTO-POLYMERIZATION  

PubMed Central

The development and processing of hybrid inorganic-organic thin film materials plays a critical role in advancing interdisciplinary sciences and device manufacturing. Here we present a novel approach to synthesize and deposit acrylate-containing organic/inorganic hybrid films. The material is based on a chemical solution and includes specifically desired metal dopants that are fully-integrated into the backbone of the polymer structure. The film can be deposited by simple spin coating, and we confer photosensitive properties to the material making it directly patterned by traditional UV photolithography techniques. Film thickness, chemical characterization and wet/dry etching capability of the film are also investigated. We believe this innovative material has the potential to be used in a broad range of applications for electronic, photonic, biology and other interdisciplinary fields. PMID:19795818

Han, Huilan; Bissell, John; Yaghmaie, Frank; Davis, Cristina E.

2009-01-01

365

FILMING OF 'CONTACT' AT LC39 PRESS SITE  

NASA Technical Reports Server (NTRS)

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.

1997-01-01

366

FILMING OF 'CONTACT' AT LC39 PRESS SITE  

NASA Technical Reports Server (NTRS)

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.

1997-01-01

367

Molecular and Culture-Based Analyses of Prokaryotic Communities from an Agricultural Soil and the Burrows and Casts of the Earthworm Lumbricus rubellus  

Microsoft Academic Search

The microbial populations in no-till agricultural soil and casts of the earthworm Lumbricus rubellus were examined by culturing and molecular methods. Clone libraries of the 16S rRNA genes were prepared from DNA isolated directly from the soil and earthworm casts. Although no single phylum dominated the soil library of 95 clones, the largest numbers of clones were from Acidobacteria (14%),

Michelle A. Furlong; David R. Singleton; David C. Coleman; William B. Whitman

2002-01-01

368

Establishing relationship between the base metal properties and friction stir welding process parameters of cast aluminium alloys  

Microsoft Academic Search

In friction stir welding (FSW), the material under the rotating action of non-consumable tool has to be stirred properly to get defect free welds in turn it will improve the strength of the welded joints. The welding conditions and parameters are differing based on the mechanical properties of base materials such as tensile strength, ductility and hardness which control the

M. Jayaraman; R. Sivasubramanian; V. Balasubramanian

2010-01-01

369

Verification of Gamma Knife extend system based fractionated treatment planning using EBT2 film  

SciTech Connect

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.

Natanasabapathi, Gopishankar; Bisht, Raj Kishor [Gamma Knife Unit, Department of Neurosurgery, Neurosciences Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029 (India)] [Gamma Knife Unit, Department of Neurosurgery, Neurosciences Centre, All India Institute of Medical Sciences, Ansari Nagar, New Delhi 110029 (India)

2013-12-15

370

Oxygen barrier performance of whey-protein-coated plastic films as affected by temperature, relative humidity, base film and protein type  

Microsoft Academic Search

Oxygen permeation properties of whey-protein-coated plastic films were examined to compare their oxygen-barrier performance as affected by temperature (15–40°C), relative humidity (30–85% RH), base film (PE: polyethylene & PP: polypropylene), and protein type (WPI: whey protein isolate & WPC: whey protein concentrate). The resulting whey-protein-coated films showed increase in oxygen permeability (OP) as temperature increased, with an Arrhenius behavior, and

Seok-In Hong; John M. Krochta

2006-01-01

371

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...

372

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)

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.

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

373

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)

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.

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

2014-08-01

374

Memory switches based on metal oxide thin films  

NASA Technical Reports Server (NTRS)

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.

Ramesham, Rajeshuni (Inventor); Thakoor, Anilkumar P. (Inventor); Lambe, John J. (Inventor)

1990-01-01

375

Carbon films from polyacrylonitrile  

SciTech Connect

Polyacrylonitrile (PAN) films have been fabricated by both spin and solvent casting techniques, and pyrolyzed to produce carbon films in the thickness range of 200--50 000 A. These films have higher electrical conductivities than carbon films produced from most other precursors at similar temperatures. The chemical structure of the films at different stages of processing was investigated by UV, IR, Raman, and XPS spectroscopies. An extra degree of control over the final electrical conductivity was obtained by varying the PAN content of copolymer precursors. Oxidation rates and an activation energy were determined. Finally, processing techniques are described which allow both dry and wet film transfer and lithographic patterning.

Renschler, C.L.; Sylwester, A.P.; Salgado, L.V.

1989-03-01

376

Fabrication and mechanical characterization of biodegradable and synthetic polymeric films: Effect of gamma radiation  

NASA Astrophysics Data System (ADS)

Chitosan (1 wt%, in 2% aqueous acetic acid solution) and starch (1 wt%, in deionised water) were dissolved and mixed in different proportions (20-80 wt% chitosan) then films were prepared by casting. Tensile strength and elongation at break of the 50% chitosan containing starch-based films were found to be 47 MPa and 16%, respectively. It was revealed that with the increase of chitosan in starch, the values of TS improved significantly. Monomer, 2-butane diol-diacrylate (BDDA) was added into the film forming solutions (50% starch-based), then casted films. The BDDA containing films were irradiated under gamma radiation (5-25 kGy) and it was found that strength of the films improved significantly. On the other hand, synthetic petroleum-based polymeric films (polycaprolactone, polyethylene and polypropylene) were prepared by compression moulding. Mechanical and barrier properties of the films were evaluated. The gamma irradiated (25 kGy) films showed higher strength and better barrier properties.

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

2012-08-01

377

Intense pulsed light treatment of cadmium telluride nanoparticle-based thin films.  

PubMed

The search for low-cost growth techniques and processing methods for semiconductor thin films continues to be a growing area of research; particularly in photovoltaics. In this study, electrochemical deposition was used to grow CdTe nanoparticulate based thin films on conducting glass substrates. After material characterization, the films were thermally sintered using a rapid thermal annealing technique called intense pulsed light (IPL). IPL is an ultrafast technique which can reduce thermal processing times down to a few minutes, thereby cutting production times and increasing throughput. The pulses of light create localized heating lasting less than 1 ms, allowing films to be processed under atmospheric conditions, avoiding the need for inert or vacuum environments. For the first time, we report the use of IPL treatment on CdTe thin films. X-ray diffraction (XRD), optical absorption spectroscopy (UV-Vis), scanning electron microscopy (SEM) and room temperature photoluminescence (PL) were used to study the effects of the IPL processing parameters on the CdTe films. The results found that optimum recrystallization and a decrease in defects occurred when pulses of light with an energy density of 21.6 J cm(-2) were applied. SEM images also show a unique feature of IPL treatment: the formation of a continuous melted layer of CdTe, removing holes and voids from a nanoparticle-based thin film. PMID:24635698

Dharmadasa, Ruvini; Lavery, Brandon; Dharmadasa, I M; Druffel, Thad

2014-04-01

378

New understanding of hardening mechanism of TiN/SiNx-based nanocomposite films  

PubMed Central

In order to clarify the controversies of hardening mechanism for TiN/SiNx-based nanocomposite films, the microstructure and hardness for TiN/SiNx and TiAlN/SiNx nanocomposite films with different Si content were studied. With the increase of Si content, the crystallization degree for two series of films firstly increases and then decreases. The microstructural observations suggest that when SiNx interfacial phase reaches to a proper thickness, it can be crystallized between adjacent TiN or TiAlN nanocrystallites, which can coordinate misorientations between nanocrystallites and grow coherently with them, resulting in blocking of the dislocation motions and hardening of the film. The microstructure of TiN/SiNx-based nanocomposite film can be characterized as the nanocomposite structure with TiN-based nanocrystallites surrounded by crystallized SiNx interfacial phase, which can be denoted by nc-TiN/c-SiNx model ('c’ before SiNx means crystallized) and well explain the coexistence between nanocomposite structure and columnar growth structure within the TiN/SiNx-based film. PMID:24134611

2013-01-01

379

Production and characterization of films from cotton stalk xylan.  

PubMed

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

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

2007-12-26

380

Large oriented arrays and continuous films of TiO2 based nanotubes.  

SciTech Connect

We report for the first time a one-step, templateless method to directly prepare large arrays of oriented TiO{sub 2}-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 TiO{sub 2} 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 TiO{sub 2} nanotubes, continuous films, and coatings are expected to have potentials for applications in catalysis, filtration, sensing, photovoltaic cells, and high surface area electrodes.

Xu, Huifang (University of New Mexico, Albuquerque, NM); Liu, Jun; Voigt, James A.; Tian, Zhengrong Ryan; McKenzie, Bonnie Beth

2003-08-01

381

Measurement of Adhesion Strength of DLC Film Prepared by Utilizing Plasma-Based Ion Implantation  

NASA Astrophysics Data System (ADS)

High-adhesion diamond-like carbon (DLC) film was prepared by a hybrid process of plasma-based ion implantation and deposition using superimposed RF and high-voltage pulses. The adhesion strength of DLC film on a stainless steel (SUS304) was enhanced by the carbon ion implantation to the substrate. Furthermore, ion implantation of mixed carbon and silicon led to considerable enhancement of adhesion strength above the resin glue strength. The adhesion strength of DLC film on the aluminum alloy (A-5052) was improved above the resin glue strength only by the carbon ion implantation to the substrate.

Oka, Yoshihiro; Yatsuzuka, Mitsuyasu

382

A tunable reflector based on VO2 thin films in terahertz optical systems  

NASA Astrophysics Data System (ADS)

We present a tunable reflector based on VO2 thin films in the terahertz frequency range. The reflectance of the reflector in the terahertz region can be tuned by controlling electrical properties of VO2 thin films. The change of electrical properties of VO2 originates from an insulator-metal transition of VO2. The experimental results demonstrated the effectiveness of the tunable reflector in the terahertz region. The tunable reflector of the VO2 thin films is very suitable for terahertz systems.

Lai, Wei en; Zhang, Huai wu; Wen, Qi ye; Qiu, Dong hong

2014-11-01

383

Chemical sensing employingpH sensitive emeraldine base thin film for carbon dioxide detection  

NASA Astrophysics Data System (ADS)

Respiration, or CO2 evolution, is a universal indicator for all the biological activities. Among many potential applications, the measurement of CO2 evolution has been found to be a rapid and nondestructive means for examining microbial contamination of food. The sensor developed in this work consists of a thin emeraldine base-polyaniline (EB-PAni) film. In the first half of the project the effect of carbon dioxide over the conductivity of a composite film of emeraldine base polyaniline and poly(vinyl alcohol) in N-methyl pyrrolidone (NMP) respectively was tested. Argon gas or mixture of argon and 5% CO2 were circulated through the glass cell containing the polymer film deposited on interdigitated electrode and exposed to specific humidity levels fixed by aqueous supersaturated salt solutions. In the second half of the project, a thin emeraldine base film in NMP was directly deposited on interdigitated electrode and the respective sensor inserted in water. Carbonic acid solutions of various pHs were generated by bubbling specific mixtures of carbon dioxide and argon. Conductivity measurements were performed by impedance spectroscopy throughout the project. The sensing mechanism is based on intermediate stages of the transformation of the emeraldine base polyaniline to a conductive salt type (ES-PAni). This EB-ES transformation is the consequence of the exposure of EB-PAni to a protonic acid and is accompanied by a change in the conductivity of the polymer film. Carbonic acid, unfortunately, is a very weak acid and is unable to induce a conductivity change, but the intermediate steps that predetermine this transformation are detected by impedance spectroscopy even when the overall conductivity of the film is unchanged. The composite thin film developed in the first part of the project showed poor sensing characteristics: limited dynamic range, drift, instability and slow time response. However, the sensor design employed in the second half of this work, coupled with impedance spectroscopy measurements, revealed valuable information about conduction mechanisms at pH levels were the overall conductivity of the film remained unchanged. Typical impedance spectra for the emeraldine thin films for a frequency sweep between 3.2 E7 to 1 Hz shows a single semicircle. The overall conductivity of the film (5x10-4 S/cm) does not change when CO 2 is bubbled through the water in which the sensor is immersed, but an additional semicircle starts to appear at low (less than 200 Hz) frequency corresponding to lowering the pH of the solution below 5.0. The original semicircle diminishes in size but maintains its initial peak frequency. The EB film is very sensitive to pH changes, therefore an additional semicircle appears in unpurified argon gas due to the reduction of the pH of water solution to 4.65. The same mechanism is displayed in hydrochloric acid solutions of various pH. The formation of the second semicircle depends on the initial conductivity of the emeraldine base film, a film displaying an initial conductivity of 4.8 x 10-3 S/cm forming the second semicircle at a pH of 5.85. The appearance of the second semicircle is most likely due to a preferential protonation in the insulating matrix of the polymer film. The overall conductivity of the film increases when the level of protonation in the insulating portion of the film reached a level close to the protonation level in the scattered metallic islands, allowing the electron-hopping mechanism to became active. The sensor output is stable and reproducible even after 11 months passed from the polymer film deposition.

Irimia-Vladu, Mihai

384

Fabrication of Graphene-Based Nanostructured Thin Films with Mid-Infrared Photoresponse Properties  

NASA Astrophysics Data System (ADS)

Graphene shows great potential as an advanced building block for fabricating varied graphene based nanostructured films together with other metal and metal oxide nanomaterials. In the current work, a new approach was developed to fabricate flexible, transparent conductive films via layer-by-layer (LbL) assembly of oppositely charged reduced graphene oxide (RGO) nanosheets. We further fabricated transparent conductive hybrid films via LbL assembly of oppositely charged RGO nanosheet and platinum (Pt) nanoparticle as well as silica (SiO2) nanoparticle. It was found that the graphene based nanostructured films showed different mid-infrared photoresponse properties. Moreover, the photoresponse performance could be manipulated by the power and distance between two electrodes.

Zhu, Jiayi; Zhang, Lin; Wu, Weidong; Cao, Yang; He, Junhui

2014-12-01

385

Reactive coating of soybean oil-based polymer on nanofibrillated cellulose film for water vapor barrier packaging.  

PubMed

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

Lu, Peng; Xiao, Huining; Zhang, Weiwei; Gong, Glen

2014-10-13

386

The mechanisms of plant stress mitigation by kaolin-based particle films and its applications in horticultural and agricultural crops  

Technology Transfer Automated Retrieval System (TEKTRAN)

Kaolin-based particle films have utility in reducing insect, heat, light, and uv stress in plants due to the reflective nature of the particles. Particle films with a residue density of 1 to 3 g/ square meter have been evaluated in a range of crops and agricultural environments. The particle film ...

387

Formation and Dielectric Properties of Polyelectrolyte Multilayers Studied by a Silicon-on-Insulator Based Thin Film Resistor  

E-print Network

Formation and Dielectric Properties of Polyelectrolyte Multilayers Studied by a Silicon multilayers (PEMs) is investigated using a silicon-on-insulator based thin film resistor which is sensitive constants of the polyelectrolyte films and in the concentration of mobile ions within the films can

Bausch, Andreas

388

Thin-film deposition of an organic magnet based on vanadium methyl tricyanoethylenecarboxylate.  

PubMed

The preparation and characterization of a new thin-film organic-based magnet V[MeTCEC]x (V = vanadium; MeTCEC = methyl tricaynoethylenecarboxylate) via low-temperature chemical vapor deposition (50 °C) is reported. These thin films exhibit room-temperature magnetic ordering and semiconducting behavior, demonstrating the ability of tuning their magnetic, and potentially spintronic, functionality via chemical modification of the organic ligand. PMID:25327816

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

2014-12-01

389

Nano-TiO 2 based multilayer film deposition on cotton fabrics for UV-protection  

Microsoft Academic Search

Nano-TiO2 based multilayer nanocomposite films were fabricated on cationically modified woven cotton fabrics by layer-by-layer molecular\\u000a self-assembly technique. Cationization process was used to obtain cationic surface charge on cotton fabrics. Attenuated total\\u000a reflectance Fourier transform infrared spectroscopy analyses were used to verify the presence of cationic surface charge and\\u000a multilayer films deposited on the fabrics. Scanning electron microscope micrographs of

?ule S. U?ur; Merih Sar??š?k; A. Hakan Akta?

2011-01-01

390

Highly Ordered LB Films of a Novel Ferric Schiff Base Complex  

Microsoft Academic Search

An amphiphlic ferric Schiff base complex, FeLCl·2H2O (L = N,N?-bis-(1-phenyl-3-methyl-4-octadecylidene-pyrazone-5-one)ethylenediamine), is newly synthesized and characterized. Surface pressure-area isotherm on pure water subphase of the complex shows stable Langmuir film-formation. UV-visible spectroscopy and low-angle x-ray diffraction indicate that LB films transferred on hydrophilic glass are of highly ordered structure.

Kezhi Wang; Masa-Aki Haga; Hideaki Monjushiro

1999-01-01

391

Structure and Function of Protein-Based Edible Films and Coatings  

Microsoft Academic Search

\\u000a Research and development on films and coatings made from various agricultural proteins has been conducted over the past 20\\u000a years, but is of heightened interest, due to the demand for environmentally-friendly, renewable replacements for petroleum-based\\u000a polymeric materials and plastics. To address this demand, films and coatings have been made from renewable resources, such\\u000a as casein, whey, soy, corn zein, collagen,

Kirsten Dangaran; Peggy M. Tomasula; Phoebe Qi

392

High-temperature tribology of silicon nitride lubricated with cesium-based inorganic films  

Microsoft Academic Search

The high temperature sliding friction and wear of silicon nitride was investigated under unlubricated and solid lubricated conditions. Experiments were performed in laboratory air (18.7% +\\/- 10.0% R.H.), mostly at 600°C, using a ball-on-disk configuration. Two cesium-based inorganic films were studied; a sodium silicate bonded cesium oxythiotungstate (Cs2WOS 3) coating and a cesium silicate chemical reaction film of the form

Lewis Rosado

2001-01-01

393

Oxidation kinetics of Ni metallic films: Formation of NiO-based resistive switching structures  

Microsoft Academic Search

Resistive switching controlled by external voltage has been reported in many Metal\\/Resistive oxide\\/Metal (MRM) structures in which the resistive oxide was simple transition metal oxide thin films such as NiO or TiO2 deposited by reactive sputtering. In this paper, we have explored the possibility to form NiO-based MRM structures from the partial oxidation of a blanket Ni metallic film using

L. Courtade; Ch. Turquat; Ch. Muller; J. G. Lisoni; L. Goux; D. J. Wouters; D. Goguenheim; P. Roussel; L. Ortega

2008-01-01

394

Cucurbit[8]uril-based stimuli-responsive films as a sacrificial layer for preparation of free-standing thin films.  

PubMed

A pseudo-polycation was prepared based on the supramolecular cucurbit[8]uril ternary complex. It was then layer-by-layer assembled with poly(acrylic acid) to fabricate a stimuli-responsive film, which exhibited disassembly properties in response to stimuli, providing a supramolecular route for the fabrication of free-standing thin films. PMID:25370182

Li, Dan-dan; Chen, Xia-chao; Ren, Ke-feng; Ji, Jian

2015-01-31

395

Hickey, C8206_all casts Hickey, C8206_all casts, page 1  

E-print Network

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

Hickey, Barbara

396

CAST FLOOR WITH VIEW OF TORPEDO LADLE (BENEATH CAST FLOOR) ...  

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

CAST FLOOR WITH VIEW OF TORPEDO LADLE (BENEATH CAST FLOOR) AND KEEPERS OF THE CAST HOUSE FLOOR, S.L. KIMBROUGH AND DAVID HOLMES. - U.S. Steel, Fairfield Works, Blast Furnace No. 8, North of Valley Road, West of Ensley-Pleasant Grove Road, Fairfield, Jefferson County, AL

397

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

PubMed

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

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

1981-01-01

398

Leaching-resistant carrageenan-based colorimetric oxygen indicator films for intelligent food packaging.  

PubMed

Visual oxygen indicators can give information on the quality and safety of packaged food in an economic and simple manner by changing color based on the amount of oxygen in the packaging, which is related to food spoilage. In particular, ultraviolet (UV)-activated oxygen indicators have the advantages of in-pack activation and irreversibility; however, these dye-based oxygen indicator films suffer from dye leaching upon contact with water. In this work, we introduce carrageenans, which are natural sulfated polysaccharides, to develop UV-activated colorimetric oxygen indicator films that are resistant to dye leakage. Carrageenan-based indicator films were fabricated using redox dyes [methylene blue (MB), azure A, and thionine], a sacrificial electron donor (glycerol), an UV-absorbing photocatalyst (TiO2), and an encapsulation polymer (carrageenan). They showed even lower dye leakage in water than conventional oxygen indicator films, owing to the electrostatic interaction of anionic carrageenan with cationic dyes. The MB/TiO2/glycerol/carrageenan oxygen indicator film was successfully bleached upon UV irradiation, and it regained color very rapidly in the presence of oxygen compared to the other waterproof oxygen indicator films. PMID:24979322

Vu, Chau Hai Thai; Won, Keehoon

2014-07-23

399

Simulation of Dimensional Changes in Steel Casting  

E-print Network

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

Beckermann, Christoph

400

14 CFR 27.621 - Casting factors.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Casting factors. 27.621 Section 27.621...Construction General § 27.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2012-01-01

401

14 CFR 29.621 - Casting factors.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Casting factors. 29.621 Section 29.621...Construction General § 29.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2013-01-01

402

14 CFR 29.621 - Casting factors.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Casting factors. 29.621 Section 29.621...Construction General § 29.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2011-01-01

403

14 CFR 27.621 - Casting factors.  

Code of Federal Regulations, 2013 CFR

...2013-01-01 2013-01-01 false Casting factors. 27.621 Section 27.621...Construction General § 27.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2013-01-01

404

14 CFR 25.621 - Casting factors.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Casting factors. 25.621 Section 25.621...Construction General § 25.621 Casting factors. (a) General. ...of this section apply to any structural castings except castings that are pressure...

2012-01-01

405

14 CFR 27.621 - Casting factors.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Casting factors. 27.621 Section 27.621...Construction General § 27.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2014-01-01

406

14 CFR 27.621 - Casting factors.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Casting factors. 27.621 Section 27.621...Construction General § 27.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2011-01-01

407

14 CFR 25.621 - Casting factors.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Casting factors. 25.621 Section 25.621...Construction General § 25.621 Casting factors. (a) General. ...of this section apply to any structural castings except castings that are pressure...

2014-01-01

408

14 CFR 27.621 - Casting factors.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false Casting factors. 27.621 Section 27.621...Construction General § 27.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2010-01-01

409

14 CFR 29.621 - Casting factors.  

Code of Federal Regulations, 2012 CFR

...2012-01-01 2012-01-01 false Casting factors. 29.621 Section 29.621...Construction General § 29.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2012-01-01

410

14 CFR 29.621 - Casting factors.  

Code of Federal Regulations, 2014 CFR

...2014-01-01 2014-01-01 false Casting factors. 29.621 Section 29.621...Construction General § 29.621 Casting factors. (a) General. ...d) of this section apply to structural castings except castings that are pressure...

2014-01-01

411

14 CFR 25.621 - Casting factors.  

Code of Federal Regulations, 2011 CFR

...2011-01-01 2011-01-01 false Casting factors. 25.621 Section 25.621...Construction General § 25.621 Casting factors. (a) General. ...of this section apply to any structural castings except castings that are pressure...

2011-01-01

412

Room temperature magnetoresistive sensor based on thick films manganese perovskite  

NASA Astrophysics Data System (ADS)

La 2/3Sr 1/3MnO 3 perovskite (LSMO), which shows a ferromagnetic transition above room temperature, is a good candidate to be used as a magnetoresistive sensor. Magnetic and transport properties of granular LSMO have been studied. Different grain size and the use of metal/insulator composites have been explored in order to optimize the magnetoresistive response. LSMO ceramic powder have been used to prepare thick films on polycrystalline Al 2O 3 substrates by screen printing. The magnetoresistive response of the grown thick films is analyzed in the range of technical fields. It is shown, that under appropriate conditions, materials having field sensitivity high enough for some applications at room temperature can be obtained. A magnetic sensor has been developed in order to show the feasibility of this material as a low-cost magnetic sensor.

Balcells, Ll; Carrillo, A. E.; Martínez, B.; Sandiumenge, F.; Fontcuberta, J.

2000-11-01

413

Silicon-based thin film solid oxide fuel cell array  

NASA Astrophysics Data System (ADS)

Solid oxide fuel cells (SOFC) have been known for their clean and efficient energy conversion. SOFCs utilize a range of ceramic electrolyte materials, with yttria stabilized zirconia (YSZ) as the most common choice. Traditional SOFCs operate at relatively high temperatures (800-1000°C) due to their low oxide ion conductivity and high activation energy. Reducing the operating temperature is important to expand the field of SOFC applications, such as power sources for portable electronics. Reducing the electrolyte thickness by means of thin film deposition techniques to the submicrometer range is one way to reduce the Ohmic loss in SOFCs at lower temperature. In this paper, a miniature thin film fuel cell array is designed and fabricated targeting at reduced operating temperature as a potential portable power source.

Su, Pei-Chen; Prinz, Fritz B.

2010-04-01

414

Method for casting polyethylene pipe  

NASA Technical Reports Server (NTRS)

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.

Elam, R. M., Jr.

1973-01-01

415

Transparent conductive film based on carbon nanotubes and PEDOT composites  

Microsoft Academic Search

Single-walled nanotubes (SWNTs), thin multiwalled carbon nanotubes (t-MWNTs) and multiwalled carbon nanotubes (MWNTs) were treated with H2SO4–HNO3 acid solution, under different chemical conditions. The acid-treated CNTs were dispersed in DI water and in poly (3,4-ethylenedioxythiophene) (PEDOT) solution. Furthermore, the finely dispersed CNTs\\/PEDOT solutions were employed to a simple method of bar coating to obtain the transparent conductive films on the

J. S. Moon; J. H. Park; T. Y. Lee; Y. W. Kim; J. B. Yoo; C. Y. Park; J. M. Kim; K. W. Jin

2005-01-01

416

Growth of diamond thin films on nickel-base alloys  

Microsoft Academic Search

Microwave plasma-assisted chemical vapor deposition has been employed to grow diamond films (thickness up to 50 ?m) using a gas mixture of hydrogen (H2), methane (CH4), and oxygen (O2) on various substrates such as Ni 200, MONEL 400, INCONEL 600, INVAR, single crystal nickel with orientations of (100), (111), etc. Nucleation of diamond on the substrates has been achieved by

R. Ramesham; M. F. Rose; R. F. Askew

1996-01-01

417

Oxide thin film based inverse superconducting spin switches  

Microsoft Academic Search

Thin film F\\/S\\/F trilayers made of YBa2Cu3O7 (S, YBCO) and La0.7Ca0.3MnO3 (F, LCMO) behave as inverse superconducting spin switches (SSS) as the critical temperature of the superconductor depends on the relative orientation of the magnetization of the F layers in a way that the resistivity is increased in the antiparallel configuration. This is caused by enhanced pair-breaking due to the

Norbert M. Nemes; C. Visani; C. Miller; M. Rocci; F. Bruno; J. Garcia-Barriocanal; Z. Sefrioui; C. Leon; J. Santamaria; M. Iglesias; F. Mompean; M. Garcia-Hernandez; A. Hoffmann; S. G. E. Te Velthuis

2009-01-01

418

Virus-PEDOT Composite Films for Impedance-Based Biosensing  

PubMed Central

Composite films composed of poly(3,4-ethylenedioxythiophene), PEDOT, and the filamentous virus M13K07 were prepared by electrooxidation of 3,4-ethylenedioxythiophene (EDOT) in aqueous solutions containing 8 nM of the virus at planar gold electrodes. These films were characterized using atomic force microscopy and scanning electron microscopy. The electrochemical impedance of virus-PEDOT films increases upon exposure to an antibody (p-Ab) that selectively binds to the M13 coat peptide. Exposure to p-Ab causes a shift in both real (ZRE) and imaginary (ZIM) impedance components across a broad range of frequencies from 50 Hz to 10 kHz. Within a narrower frequency range from 250 Hz to 5 kHz, the increase of the total impedance (Ztotal) with p-Ab concentration conforms to a Langmuir adsorption isotherm over the concentration range from from 6 to 66 nM, yielding a value for Kd = 16.9 nM at 1000 Hz. PMID:21388148

Donavan, Keith C.; Arter, Jessica A.; Pilolli, Rosa; Cioffi, Nicola

2011-01-01

419

Wear behavior of alloyed hypereutectic gray cast iron  

Microsoft Academic Search

Alloyed gray cast iron of varying compositions was studied for their wear behavior. In general, the alloyed gray irons studied have higher graphite volume fraction (?20%) with Type-A graphite flake morphology. Base cast iron showed two to three times higher wear rates than the alloyed gray irons. Tensile strength and wear rates show decreasing trend with increase in graphite and

Aravind Vadiraj; G. Balachandran; M. Kamaraj; B. Gopalakrishna; D. Venkateshwara Rao

2010-01-01

420

The selection of the casting process using an expert system  

Microsoft Academic Search

This paper presents an expert system for the selection of casting processes. The selection criteria are based on the production, design, manufacturing as well as trade-off attributes. The objective of the present work is to aid the designer in adequately selecting casting processes for the production of components.

S. M. Darwish; A. M. El-Tamimi

1996-01-01

421

Breaking the Caste Barrier: Intergenerational Mobility Viktoria Hnatkovskay  

E-print Network

Breaking the Caste Barrier: Intergenerational Mobility in India Viktoria Hnatkovskay , Amartya coincided with a breaking down of caste-based historical barriers to socio-economic mobility. JEL Classi and the ISI Growth conference for comments. Special thanks to David Green for extremely helpful and detailed

Bandyopadhyay, Antar

422

INTEGRATED DESIGN OF STEEL CASTINGS FOR SERVICE PERFORMANCE  

E-print Network

that castings pass specified NDT standards without knowing exactly how this translates to part performance on case-by-case experience. Progress on the topic has not advanced much beyond this point despite great are available only for long-run, mass-produced components. Having such a knowledge-base for all steel castings

Beckermann, Christoph

423

Water Modeling of Twin-Roll Strip Casting  

Microsoft Academic Search

Twin-roll strip casting is regarded as a prospective technology of near net shape continuous casting. The fluid flow field and level fluctuation in the pool have a strong influence not only on composition and temperature homogeneity of pool, but also on the strip quality. A 1 : 1 water model of a twin-roll strip caster was set up based on

Bo WANG; Jie-yu ZHANG; Jun-fei FAN; Shun-li ZHAO; Yuan FANG; Sheng-li AN

2006-01-01

424

Advanced Pattern Material for Investment Casting Applications  

SciTech Connect

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.

F. Douglas Neece Neil Chaudhry

2006-02-08

425

Temperature dependence of a nanoporous Pd film hydrogen sensor based on an AAO template on Si  

NASA Astrophysics Data System (ADS)

In this study, hydrogen sensing properties of nanoporous Pd films based on Anodic Aluminium Oxide (AAO) templates grown on a silicon substrate have been investigated at various temperatures (25-100°C) and hydrogen concentrations (100-1000 ppm) to determine the temperature-sensitivity relationship. For this purpose, a hexagonally shaped AAO template of approximately 50 nm in diameter and 700 nm in length with 80 nm interpore distances was fabricated using two-step anodization of an Al film deposited on an n-type (100) oriented oxidized Si substrate. Then, the nanoporous surface of the AAO template was used as a substrate for supporting a nanoporous Pd film of an approximately thickness of 60 nm. The morphologies of the AAO template and Pd film coated on the AAO template were studied mainly by Scanning Electron Microscopy (SEM). Hydrogen sensing properties of the nanoporous Pd film were measured using a resistance transient method. It was found that the sensor response of the nanoporous Pd films on the AAO template was better than the traditional Pd thin film sensors, the sensitivity of the sensor was approximately 1.8% for 1000 ppm H2, and the detection limit was lower than 100 ppm at room temperature. The highest sensitivity was measured at room temperature.

Ta?alt?n, Nevin; Öztürk, Sadullah; K?l?nç, Necmettin; Ziya Öztürk, Zafer

2009-12-01

426

Electronic properties of ultrathin films based on pyrrolofullerene molecules on the surface of oxidized silicon  

NASA Astrophysics Data System (ADS)

Results of the investigation into the interface formation during the deposition of the films based on aziridinylphenylpyrrolofullerene (APP-C60) up to 8 nm thick on the surface of the oxidized silicon substrate are presented. The procedure of detecting reflection of testing low-energy electron beam from the surface implemented in the total current spectroscopy mode with a change in the incident electron energy from 0 to 25 eV is used. The structure of maxima in the total current spectra induced by the APP-C60 deposited film is established, and the character of interrelation of these maxima with ?* and ?* energy bands in the studied materials is determined. It is revealed due to analyzing the variation in intensities of the total current spectra of the deposited APP-C60 film and the (SiO2) n-Si substrate that the APP-C60 film is formed at the early deposition stage with the coating thickness thinner than one monolayer without the formation of the intermediate modified organic layer. As the APP-C60/(SiO2) n-Si interface is formed, the work function of the surface increases by 0.7 eV, which corresponds to the transfer of the electron density from substrate (SiO2) n-Si toward the film APP-C60. The optical absorption spectra of the APP-C60 films are measured and compared with the spectra of films of unsubstituted C60.

Komolov, A. S.; Lazneva, E. F.; Gerasimova, N. B.; Gavrikov, A. A.; Khlopov, A. E.; Akhremchik, S. N.; Zimina, M. V.; Panina, Yu. A.; Povolotskii, A. V.; Konev, A. S.; Khlebnikov, A. F.

2014-08-01

427

Temperature dependence of resistive switching behaviors in resistive random access memory based on graphene oxide film  

NASA Astrophysics Data System (ADS)

We reported resistive switching behaviors in the resistive random access memory (RRAM) devices based on the different annealing temperatures of graphene oxide (GO) film as active layers. It was found that the resistive switching characteristics of an indium tin oxide (ITO)/GO/Ag structure have a strong dependence on the annealing temperature of GO film. When the annealing temperature of the GO film was 20 °C, the devices showed typical write-once-read-many-times (WORM) type memory behaviors, which have good memory performance with a higher ON/OFF current ratio (˜104), the higher the high resistance state (HRS)/low resistance state (LRS) ratio (˜105) and stable retention characteristics (>103 s) under lower programming voltage (-1 V and -0.5 V). With the increasing annealing temperature of GO film, the resistive switching behavior of RRAM devices gradually weakened and eventually disappeared. This phenomenon could be understood by the different energy level distributions of the charge traps in GO film, and the different charge injection ability from the Ag electrode to GO film, which is caused by the different annealing temperatures of the GO film.

Yi, Mingdong; Cao, Yong; Ling, Haifeng; Du, Zhuzhu; Wang, Laiyuan; Yang, Tao; Fan, Quli; Xie, Linghai; Huang, Wei

2014-05-01

428

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

PubMed

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

Borreani, Giorgio; Tabacco, Ernesto

2015-01-01

429

Temperature dependence of resistive switching behaviors in resistive random access memory based on graphene oxide film.  

PubMed

We reported resistive switching behaviors in the resistive random access memory (RRAM) devices based on the different annealing temperatures of graphene oxide (GO) film as active layers. It was found that the resistive switching characteristics of an indium tin oxide (ITO)/GO/Ag structure have a strong dependence on the annealing temperature of GO film. When the annealing temperature of the GO film was 20 °C, the devices showed typical write-once-read-many-times (WORM) type memory behaviors, which have good memory performance with a higher ON/OFF current ratio (?10(4)), the higher the high resistance state (HRS)/low resistance state (LRS) ratio (?10(5)) and stable retention characteristics (>10(3) s) under lower programming voltage (-1 V and -0.5 V). With the increasing annealing temperature of GO film, the resistive switching behavior of RRAM devices gradually weakened and eventually disappeared. This phenomenon could be understood by the different energy level distributions of the charge traps in GO film, and the different charge injection ability from the Ag electrode to GO film, which is caused by the different annealing temperatures of the GO film. PMID:24739543

Yi, Mingdong; Cao, Yong; Ling, Haifeng; Du, Zhuzhu; Wang, Laiyuan; Yang, Tao; Fan, Quli; Xie, Linghai; Huang, Wei

2014-05-01

430

Rapid casting solutions: a review  

Microsoft Academic Search

Purpose – This paper seeks to review the industrial applications of state-of-the-art additive manufacturing (AM) techniques in metal casting technology. An extensive survey of concepts, techniques, approaches and suitability of various commercialised rapid casting (RC) solutions with traditional casting methods is presented. Design\\/methodology\\/approach – The tooling required for producing metal casting such as fabrication of patterns, cores and moulds with

Munish Chhabra; Rupinder Singh

2011-01-01

431

Casting Of Multilayer Ceramic Tapes  

NASA Technical Reports Server (NTRS)

Procedure for casting thin, multilayer ceramic membranes, commonly called tapes, involves centrifugal casting at accelerations of 1,800 to 2,000 times normal gravitational acceleration. Layers of tape cast one at a time on top of any previous layer or layers. Each layer cast from slurry of ground ceramic suspended in mixture of solvents, binders, and other components. Used in capacitors, fuel cells, and electrolytic separation of oxygen from air.

Collins, Earl R., Jr.

1991-01-01

432

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

E-print Network

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 of the semiconductor layers in the fabrication of CdS/CdTe cells. The effort on high efficiency a-Si materials is led

Deng, Xunming

433

Numerical study of porosity in titanium dental castings.  

PubMed

A commercial software package, MAGMASOFT (MAGMA Giessereitechnologie GmbH, Aachen, Germany), was used to study shrinkage and gas porosity in titanium dental castings. A geometrical model for two simplified tooth crowns connected by a connector bar was created. Both mold filling and solidification of this casting model were numerically simulated. Shrinkage porosity was quantitatively predicted by means of a built-in feeding criterion. The risk of gas pore formation was investigated using the numerical filling and solidification results. The results of the numerical simulations were compared with experiments, which were carried out on a centrifugal casting machine with an investment block mold. The block mold was made of SiO2 based slurry with a 1 mm thick Zr2 face coat to reduce metal-mold reactions. Both melting and casting were carried out under protective argon (40 kPa). The finished castings were sectioned and the shrinkage porosity determined. The experimentally determined shrinkage porosity coincided with the predicted numerical simulation results. No apparent gas porosity was found in these model castings. Several running and gating systems for the above model casting were numerically simulated. An optimized running and gating system design was then experimentally cast, which resulted in porosity-free castings. PMID:15348102

Wu, M; Sahm, P R; Augthun, M; Spiekermann, H; Schädlich-Stubenrauch, J

1999-09-01

434

Erasable thin-film optical diode based on a photoresponsive liquid crystal polymer  

NASA Astrophysics Data System (ADS)

We report a thin-film optical diode written into thin films of a liquid-crystalline polymer (LCP), which is based on the photoinduced LC-to-isotropic phase transition of LCPs. The interference pattern between a collimated and a focused UV laser beam is imprinted as chirped volume-phase gratings in photoresponsive LCP films and no further processing steps like development or liftoff are required for the fabrication. The resultant thin-film device not only possesses the fundamental functions of an optical lens for laser beam focusing, but also shows diode effects with the focusing/defocusing function dependent on the direction of light incidence and orientation of the device. Furthermore, this photonic thin-film lens exhibits a spatially tunable spectroscopic response, revealing a unique physics of secondary excitations of resonance modes of the single-layer LCP waveguide grating structures. This reveals the mechanisms for the focusing/defocusing of laser beams by chirped grating structures. Erasability and reconstructibility of the photoresponsive LCPs guarantee rewritability of the thin-film diode lens.We report a thin-film optical diode written into thin films of a liquid-crystalline polymer (LCP), which is based on the photoinduced LC-to-isotropic phase transition of LCPs. The interference pattern between a collimated and a focused UV laser beam is imprinted as chirped volume-phase gratings in photoresponsive LCP films and no further processing steps like development or liftoff are required for the fabrication. The resultant thin-film device not only possesses the fundamental functions of an optical lens for laser beam focusing, but also shows diode effects with the focusing/defocusing function dependent on the direction of light incidence and orientation of the device. Furthermore, this photonic thin-film lens exhibits a spatially tunable spectroscopic response, revealing a unique physics of secondary excitations of resonance modes of the single-layer LCP waveguide grating structures. This reveals the mechanisms for the focusing/defocusing of laser beams by chirped grating structures. Erasability and reconstructibility of the photoresponsive LCPs guarantee rewritability of the thin-film diode lens. Electronic supplementary information (ESI) available. See DOI: 10.1039/c3nr06623a

Zhang, Xinping; Zhang, Jian; Sun, Yujian; Yang, Huai; Yu, Haifeng

2014-03-01

435

Replacing London's cast iron mains  

Microsoft Academic Search

This paper discusses the cast iron gas distribution systems that exist in many cities and contains considerable amounts of pipe that vary in age from 20 to 150 years. In many ways, cast iron is an excellent material. It is inherently corrosion resistant, easy to install and cheap. However, it is also brittle and smaller diameter cast iron pipe has

A. Thorne; P. Mathews

1992-01-01

436

Casting and Angling.  

ERIC Educational Resources Information Center

The self-contained packet contains background information, lesson plans, 15 transparency and student handout masters, drills and games, 2 objective examinations, and references for teaching a 15-day unit on casting and angling to junior high and senior high school students, either as part of a regular physical education program or as a club…

Little, Mildred J.; Bunting, Camille

437

Enhancements in Magnesium Die Casting Impact Properties  

SciTech Connect

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.

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

2000-06-30

438

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

ERIC Educational Resources Information Center

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…

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

2013-01-01

439

Study of the variation of the optical constants of the aluminum-based multilayer thin films  

NASA Astrophysics Data System (ADS)

The effective optical constants of aluminum-based multilayer metallic thin films (Ti/Al bilayer and Ag/Ti/Al trilayer) annealed at low temperature in air were determined by using the Krestchmann configuration in the attenuated total reflection (ATR) angular scan experiment. The theoretical reflectivity functions with and without the inclusion of the aluminum oxide layer correction were used in the data fitting procedure. The actual film thicknesses were also measured by an A-scope interferometer. The analysis of the penetration depths suggested that the ATR approach is more suitable than the normal incidence reflectivity for studying the effective multilayer optical constants. Good agreement with the reflectivity data as well as the actual film thicknesses also suggested that the optical properties of these multilayer metallic thin films can be properly represented by one set of effective optical constants. The effective optical constants of Ti/Al bilayer and Ag/Ti/Al trilayer films obtained from fitting the data were shown to have a non-linear functional dependence on the atomic fractions of Ti and Al. The results of the Rutherford backscattering spectroscopy (RBS) confirmed the compositions of the bilayer and trilayer films as well as the existence of the oxide layer. The calculated atomic fractions of Ti for Ti/Al bilayer and Ag/Ti/Al trilayer films were close to those obtained from the RBS spectra. During the crystallization of thin metal films, there is a stronger tendency for Ag rather than Al to form the FCC crystal structure during the formation of an ultra-thin film.

Yang, Henglong

1997-09-01

440

Low-cost flexible thin film thermoelectric generator on zinc based thermoelectric materials  

NASA Astrophysics Data System (ADS)

The high cost and complex production technique restrict the use of the conventional thermoelectric generators. In this work, we demonstrate a promising flexible thin film thermoelectric generator using the N-type Al-doped ZnO and P-type Zn-Sb based thin film. By using the cost-effective zinc based thermoelectric materials and flexible substrate, we greatly reduce the cost production of thin film thermoelectric generator. The maximum output power of our device with 10 couples is 246.3 ?W when the temperature difference is 180 K. The maximum output power of the flexible thin film thermoelectric generator produced per couple and per unit temperature difference was 0.14 ?W per K-couple, which is about several times that of other thin film reported. The thin film thermoelectric generator with low cost and excellent output power was fabricated on flexible substrate, which is can be made into various shapes for micro- and nano-energy application.

Fan, Ping; Zheng, Zhuang-hao; Li, Yin-zhen; Lin, Qing-yun; Luo, Jing-ting; Liang, Guang-xing; Cai, Xing-ming; Zhang, Dong-ping; Ye, Fan

2015-02-01

441

Solution-based assembly of conductive gold film on flexible polymer substrates.  

PubMed

Conductive films of gold were assembled on flexible polymer substrates such as Kapton and polyethylene using a solution-based process. The polymer substrates were modified by using argon plasma and subsequent coupling of silanes with amino- or mercapto- terminal groups. These modified surfaces were examined by X-ray photoelectron spectroscopy and contact angle measurements. Colloidal gold was assembled onto the silane-modified surface from solution. The gold particles are attached to the surface by covalent interactions with the thiol or amine group. Formation of a conductive film is achieved by increasing the coverage of gold by using a "seeding" method to increase the size of the attached gold particles. Field emission scanning electron microscopy was used to follow the growth of the film. The surface resistance of the films, measured using a four-point probe, was about 1 Omega/sq. PMID:15379520

Supriya, Lakshmi; Claus, Richard O

2004-09-28

442

Solution-based synthesis of crystalline silicon thin films from liquid silane inks  

NASA Astrophysics Data System (ADS)

Silicon (Si) dominates the photovoltaics industry and there is a need for new approaches that can significantly reduce fabrication cost. In this context, we report a non-vacuum, solution-based process for the synthesis of crystalline silicon (c-Si) thin films from liquid cyclohexasilane (CHS) in a platform that is readily applicable to large-area flexible devices. UV-polymerization during spin coating leads to the formation of thin films, which were crystallized via thermal and laser annealing. Structural changes in the films were examined using SEM, AFM and Raman spectroscopy. Subsequent chemical annealing through atmospheric-pressure hydrogen plasma treatment led to a four-decade enhancement in film conductivity, which we attribute to a disorder-order transition in a bonded Si network.

Iyer, Ganjigunte R. S.; Guruvenket, S.; Hoey, Justin M.; Anderson, Kenneth J.; Schulz, Douglas L.; Swenson, Orven F.; Elangovan, S.; Boudjouk, P.; Hobbie, Erik K.

2012-02-01

443

The X-ray Telescope of CAST  

E-print Network

The Cern Axion Solar Telescope (CAST) is in operation and taking data since 2003. The main objective of the CAST experiment is to search for a hypothetical pseudoscalar boson, the axion, which might be produced in the core of the sun. The basic physics process CAST is based on is the time inverted Primakoff effect, by which an axion can be converted into a detectable photon in an external electromagnetic field. The resulting X-ray photons are expected to be thermally distributed between 1 and 7 keV. The most sensitive detector system of CAST is a pn-CCD detector combined with a Wolter I type X-ray mirror system. With the X-ray telescope of CAST a background reduction of more than 2 orders off magnitude is achieved, such that for the first time the axion photon coupling constant g_agg can be probed beyond the best astrophysical constraints g_agg < 1 x 10^-10 GeV^-1.

M. Kuster; H. Bräuninger; S. Cébrian; M. Davenport; C. Elefteriadis; J. Englhauser; H. Fischer; J. Franz; P. Friedrich; R. Hartmann; F. H. Heinsius; D. H. H. Hoffmann; G. Hoffmeister; J. N. Joux; D. Kang; K. Königsmann; R. Kotthaus; T. Papaevangelou; C. Lasseur; A. Lippitsch; G. Lutz; J. Morales; A. Rodríguez; L. Strüder; J. Vogel; K. Zioutas

2007-05-10

444

Optical multilayer films based on an amorphous fluoropolymer  

SciTech Connect

Multilayered coatings were made by physical vapor deposition (PVD) of a perfluorinated amorphous polymer, Teflon AF2400, and with other optical materials. A high reflector for 1064 nm light was made with ZnS and AF2400. An all-organic 1064 nm reflector was made from AF2400 and polyethylene. Oxide (HfO{sub 2} and SiO{sub 2}) compatibility with AF2400 was also tested. The multilayer morphologies were influenced by coating stress and unintentional temperature rises from the PVD process. Analysis by liquid nuclear magnetic resonance of the thin films showed slight compositional variations between the coating and starting materials of perfluorinated amorphous polymers.

Chow, R.; Loomis, G.E.; Ward, R.L. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

1996-01-01

445

Spray casting project final report  

SciTech Connect

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.

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

1996-08-01

446

Rapid cycle casting of steel  

NASA Astrophysics Data System (ADS)

A rapid cycle casting process for steel via diffusion solidification (SD) is developed. Solidification takes place by carbon redistribution between iron saturated high carbon liquid iron and low carbon preexisting solid iron in a refractory mold. The solidification time is shorter and the economic scaling law is less dependent on the size of the casting than in conventional casting processes. The metallurgical and processing aspects of SD casting are addressed and the necessary parameters are developed to design a rapid cycle casting machine. These process parameters in addition to the metallurgical quality variables are included in an economic feasibility analysis of the SD process.

Apelian, D.; Langford, G.

1981-07-01