film casting process: Topics by WorldWideScience.org

Sample records for film casting process

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

Science.gov (United States)

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

2016-04-01

Films prepared from silk fibroin have shown potential as biomaterials in tissue engineering applications for the eye. Here, we present a novel process for fabrication of silk fibroin films for corneal application. In this work, fabrication of silk fibroin films was simply achieved by centrifugal force. In contrast to the conventional dry casting method, we carried out the new process in a centrifuge with a rotating speed of 4000 rpm, where centrifugal force was imposed on an aluminum tube containing silk fibroin solution. In the present study, we also compared the surface roughness, mechanical properties, transparency, and cell proliferation between centrifugal and dry casting method. In terms of surface morphology, films fabricated by the centrifugal casting have less surface roughness than those by the dry casting. For elasticity and transparency, silk fibroin films obtained from the centrifugal casting had favorable results compared with those prepared by dry casting. Furthermore, primary human corneal keratocytes grew better in films prepared by the centrifugal casting. Therefore, our results suggest that this new fabrication process for silk fibroin films offers important potential benefits for corneal tissue regeneration. © 2015 Wiley Periodicals, Inc.
On the membrane approximation in isothermal film casting

Science.gov (United States)

Hagen, Thomas

2014-08-01

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

Science.gov (United States)

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

2016-06-01

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

Energy Technology Data Exchange (ETDEWEB)

Zhang, Hong; Zhang, Li, E-mail: lizhang@mae.cuhk.edu.hk [Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Shatin N.T., Hong Kong (China); Chow Yuk Ho Technology Centre for Innovative Medicine, The Chinese University of Hong Kong, Shatin N.T., Hong Kong (China)

2015-01-19

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

DEFF Research Database (Denmark)

Duffy, Claudia M.; Andreasen, Jens Wenzel; Breiby, Dag W.

2008-01-01

We investigate the growth and field-effect transistor performance of aligned pentacene thin films deposited by zone-casting from a solution of unsubstituted pentacene molecules in a chlorinated solvent. Polarized optical microscopy shows that solution processed pentacene films grow as large...
SPH based modelling of oxide and oxide film formation in gravity die castings

International Nuclear Information System (INIS)

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

2015-01-01

Gravity die casting is an important casting process which has the capability of making complicated, high-integrity components for e.g. the automotive industry. Oxides and oxide films formed during filling affect the cast product quality. The Smoothed particle hydrodynamics (SPH) method is particularly suited to follow complex flows. The SPH method has been used to study filling of a gravity die including the formation and transport of oxides and oxide films for two different filling velocities. A low inlet velocity leads to a higher amount of oxides and oxide films in the casting. The study demonstrates the usefulness of the SPH method for an increased understanding of the effect of different filling procedures on the cast quality. (paper)
Tape casting and partial melting of Bi-2212 thick films

Energy Technology Data Exchange (ETDEWEB)

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

1994-12-31

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

Science.gov (United States)

Claro, Pedro Ivo Cunha; Corrêa, Ana Carolina; de Campos, Adriana; Rodrigues, Vanessa Bolzan; Luchesi, Bruno Ribeiro; Silva, Luiz Eduardo; Mattoso, Luiz Henrique Capparelli; Marconcini, José Manoel

2018-02-01

A wide variety of new green materials such as curaua leaf fibers (CLFs) has potential applications in nanotechnology. This study aims to investigate the thermomechanical properties and morphological structure of cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) films obtained by continuous casting. The CNCs were obtained by acid hydrolysis and CNFs by mechanical shearing from bleached CLFs and eucalyptus pulp. The morphology after continuous casting resulted in oriented nanofibers, and as a consequence there was mechanical anisotropy. CNCs films showed the greatest values of tensile strength (36±4MPa) and the more effective fibrillation provided better mechanical strength of eucalyptus CNFs films than curaua CNFs films. Sulfur groups and mechanical shear degradation affected the stability of CNCs and CNFs films, respectively. Thus, the type of nanostructure, the way they interact to each other, the cellulose source and the process interfere significantly on the properties of the films. Copyright © 2017 Elsevier Ltd. All rights reserved.
Ultrasonic Substrate Vibration-Assisted Drop Casting (SVADC) for the Fabrication of Photovoltaic Solar Cell Arrays and Thin-Film Devices.

Science.gov (United States)

Eslamian, Morteza; Zabihi, Fatemeh

2015-12-01

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

Directory of Open Access Journals (Sweden)

Kalyan Kumar Mistry

2007-04-01

Full Text Available Meso-porous g-Al2O3 film may be used as a highly sensitive trace moisture sensor. The crack-free alumina film was developed using a combination of sol-gel and tape casting processes, which produce high porosity, high surface area and small pore dimensions in the range of few nano-meter at uniform distribution. Sol-gel processes are well known in nano-technology and nano-material preparation, but it is difficult to make crack-free thick or thin films using this method. Tape cast methods are used for the fabrication of flexible crack-free thick ceramic sheets. Our objective was to develop nano-structured, crack-free, transparent Al2O3 film a few microns thick, has a highly porous and stable crystallographic nature. A metallic paste was printed by screen printing on both side of the film surface for electrodes to form a sensitive element. A silver wire (dia j=0.1mm lead was connected to a grid structure electrode using a silver paste spot for fine joining. Alumina is absorbs moisture molecules into its meso-porous layer and changes its electrical characteristics according to the moisture content, its dielectric constant increase as moisture increase. Moisture molecules can be conceived of as dipoles in random state before the application of an electric field. When the dipole orientation was changed from random to an equilibrium state under the application of external field, a large change in dielectric constant was observed. The number of water molecules absorbed determines the electrical impedance of the capacitor, which in turn is proportional to water vapor pressure.
Electroactive cytochrome P450BM3 cast polyion films on graphite electrodes

International Nuclear Information System (INIS)

Pardo-Jacques, Aurelie; Basseguy, Regine; Bergel, Alain

2006-01-01

Films of electrochemically active cytochrome P450 BM 3 were constructed on graphite electrodes using alternate assembly with polyethyleneimine (PEI). The original layer-by-layer adsorption method was slightly modified here to form so-called 'cast polyion' films. The cast polyion films were elaborated by immobilizing two successive layers of PEI and protein in very large excess with respect to a monolayer, without any intermediate washing step. Following the immobilization steps by SEM showed that uniform films of a few micrometers were deposited on the graphite surface. The electrochemically activity of the immobilized cytP450 was tested with regard to the reduction of oxygen and the one-electron reduction of the heme. Cyclic voltammetry indicated surface concentration of electrochemically active cytP450 around 0.6nmol/cm 2 , which corresponded to 5% of the total amount of protein that was consumed by the immobilisation process. Adapting the procedure to a graphite felt electrode with the view of scaling up porous electrodes for large scale synthesis increased the concentration to 0.9nmol/cm 2 . Cast polyion films may represent a simple technique to immobilize high amount of electrochemically active protein, keeping the advantage of the electrostatic interactions of the regular layer-by-layer method
NdFeB thick films prepared by tape casting

International Nuclear Information System (INIS)

Pawlowski, B.; Schwarzer, S.; Rahmig, A.; Toepfer, J.

2003-01-01

NdFeB films of thickness between 100 and 800 μm were prepared by tape casting of a slurry containing 84-95 wt% of commercial NdFeB powder (MQP-B, -Q and -S). After curing the flexible green tapes at 120 deg. C non-porous magnetic films are obtained. The remanence of the films is in the range of 350-450 mT and the coercivity is between 300 and 800 kA/m depending on the type of MQP powder used. The magnetic properties of the films are discussed in relation to film composition and type of magnetic material. For MEMS applications the thick films are magnetized with a multi-pole stripe pattern with 1 mm pole pitch. The induction at the surface of the films was measured with a Hall probe and compared to theoretical calculations. The results indicate that the films are completely magnetized regardless of the film thickness. Tape-casted NdFeB thick films are promising candidates for applications in micro-systems or actuators. Miniaturization of the magnet components is one of the key issues in the development of electromagnetic micro-systems, thus creating a need for replacement of small sintered magnets by magnetic thick film components. Other applications include encoders
Influence of reaction chamber shape on cast-iron spheroidization process in-mold

Directory of Open Access Journals (Sweden)

S. Pietrowski

2010-01-01

Full Text Available This paper presents a results concerning the influence of reaction chamber shape on cast – iron spheroidization process in form. The volume of the tested reaction chambers was about 118000mm3. Reaction chambers in the shape of: rectangular, cylinder and spherical cap were examined. It has been shown that the best graphite spheroidizing process was provided by spherical cap chamber shape. The reaction of cast – iron with magnesium in reaction chamber depends on the flow of cast – iron in the chamber. In rectangular and cylinder shape chambers proceed the impact of diphase stream on flat bottom wall. It causes the creation on its surface film, called: cast – iron “film”, where single grains of magnesium master alloy exist. The largest part of master alloy is drifted by liquid cast – iron to the top and only there graphite spheroidization process proceed. In the spherical cap shape reaction chamber, as a result of rotation movement of liquid cast – iron throughout its volume, graphite spheroidization process proceed. Apart from the reaction chamber shape, applying of mixing chamber ensure full cast – iron spheroidization process.
Large-area graphene films by simple solution casting of edge-selectively functionalized graphite.

Science.gov (United States)

Bae, Seo-Yoon; Jeon, In-Yup; Yang, Jieun; Park, Noejung; Shin, Hyeon Suk; Park, Sungjin; Ruoff, Rodney S; Dai, Liming; Baek, Jong-Beom

2011-06-28

We report edge-selective functionalization of graphite (EFG) for the production of large-area uniform graphene films by simply solution-casting EFG dispersions in dichloromethane on silicon oxide substrates, followed by annealing. The resultant graphene films show ambipolar transport properties with sheet resistances of 0.52-3.11 kΩ/sq at 63-90% optical transmittance. EFG allows solution processing methods for the scalable production of electrically conductive, optically transparent, and mechanically robust flexible graphene films for use in practice.
Preparation and Characterization of Anode-Supported YSZ Thin Film Electrolyte by Co-Tape Casting and Co-Sintering Process

International Nuclear Information System (INIS)

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

2011-01-01

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 x 7.8cm were achieved with good flatness. Scanning electron microscopy (SEM) observation indicated that the YSZ electrolyte film was about 16 μm 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)MnO 3 -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/cm 2 at 800 deg. C. The obtained results represent the important progress in the development of anode-supported intermediate temperature SOFC with reduced fabrication cost.
Preparation and Characterization of Anode-Supported YSZ Thin Film Electrolyte by Co-Tape Casting and Co-Sintering Process

Science.gov (United States)

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

2011-06-01

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

Science.gov (United States)

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

2016-05-01

Antimicrobial edible films based on sodium caseinate, glycerol, and 2 food preservatives (nisin or natamycin) were prepared by classical thermomechanical processes. Food preservatives were compounded (at 65 °C for 2.5 min) with sodium caseinate in a twin-screw extruder. Anti-Listeria activity assays revealed a partial inactivation of nisin following compounding. Thermoplastic pellets containing food preservatives were then used to manufacture films either by blown-film extrusion process or by heat-press. After 24 h of incubation on agar plates, the diameters of K. rhizophila growth inhibition zones around nisin-incorporated films prepared by solution casting (control), extrusion blowing or heat pressing at 80 °C for 7 min of nisin-containing pellets were 15.5 ± 0.9, 9.8 ± 0.2, and 8.6 ± 1.0 mm, respectively. Since heat-pressing for 7 min at 80 °C of nisin-incorporated pellets did not further inactivate nisin, this indicates that nisin inactivation during extrusion-blowing was limited. Moreover, the lower diameter of the K. rhizophila growth inhibition zone around films prepared with nisin-containing pellets compared to that observed around films directly prepared by solution casting confirms that nisin inactivation mainly occurred during the compounding step. Natamycin-containing thermoplastic films inhibited Aspergillus niger growth; however, by contrast with nisin-containing films, heat-pressed films had higher inhibition zone diameters than blown films, therefore suggesting a partial inactivation of natamycin during extrusion-blowing. © 2016 Institute of Food Technologists®
Study of self-assembled triethoxysilane thin films made by casting neat reagents in ambient atmosphere

International Nuclear Information System (INIS)

Yang Yongan; Bittner, Alexander M.; Baldelli, Steve; Kern, Klaus

2008-01-01

We studied four trialkoxysilane thin films, fabricated via self-assembly by casting neat silane reagents onto hydrophilic SiO x /Si substrates in the ambient. This drop-casting method is simple, yet rarely studied for the production of silane self-assembled monolayers (SAMs). Various ex-situ techniques were utilized to systematically characterize the growth process: Ellipsometry measurements can monitor the evolution of film thickness with silanization time; water droplet contact angle measurements reveal the wettability; the change of surface morphology was followed by Atomic Force Microscopy; the chemical identity of the films was verified by Infrared-Visible Sum Frequency Generation spectroscopy. We show that the shorter carbon chain (propyl-) or branched (2-(diphenylphosphino)ethyl-) silane SAMs exhibit poor ordering. In contrast, longer carbon chain (octadecyl and decyl) silanes form relatively ordered monolayers. The growth of the latter two cases shows Langmuir-like kinetics and a transition process from lying-down to standing-up geometry with increasing coverage
The effect of tape casting operational parameters on the quality of adjacently graded ceramic film

DEFF Research Database (Denmark)

Bulatova, Regina; Gudik-Sørensen, Mads; Della Negra, Michela

2016-01-01

For small length tape casting of ceramic slurries varying green film thickness is often a problem. To optimise this, the following parameters were investigated: single blade, double blade, using a pump system and a modelled speed change mode have been analysed. Advantages and limitations of every...... method are described here. The tape casting experiments were built to be generic in order to allow the control of various processing conditions. From these results, the single-blade technique was chosen for a study of side-by-side tape casting. The influence of the geometric parameters of partitioning...... the casting tank into chambers, on the quality of graded tape was studied. Tape casting experiments at different speeds and partition tongue lengths in combination with rheological tests revealed that high casting speeds and absence of the partition under the blade are detrimental to the formation...
Zero-order release of poorly water-soluble drug from polymeric films made via aqueous slurry casting.

Science.gov (United States)

Zhang, Lu; Alfano, Joy; Race, Doran; Davé, Rajesh N

2018-05-30

In spite of significant recent interest in polymeric films containing poorly water-soluble drugs, dissolution mechanism of thicker films has not been investigated. Consequently, release mechanisms of poorly water-soluble drugs from thicker hydroxypropyl methylcellulose (HPMC) films are investigated, including assessing thickness above which they exhibit zero-order drug release. Micronized, surface modified particles of griseofulvin, a model drug of BSC class II, were incorporated into aqueous slurry-cast films of different thicknesses (100, 500, 1000, 1500 and 2000 μm). Films 1000 μm and thicker were formed by either stacking two or more layers of ~500 μm, or forming a monolithic thick film. Compared to monolithic thick films, stacked films required simpler manufacturing process (easier casting, short drying time) and resulted in better critical quality attributes (appearance, uniformity of thickness and drug per unit area). Both the film forming approaches exhibited similar release profiles and followed the semi-empirical power law. As thickness increased from 100 μm to 2000 μm, the release mechanism changed from Fickian diffusion to zero-order release for films ≥1000 μm. The diffusional power law exponent, n, achieved value of 1, confirming zero-order release, whereas the percentage drug release varied linearly with sample surface area, and sample thickness due to fixed sample diameter. Thus, multi-layer hydrophilic polymer aqueous slurry-cast thick films containing poorly water-soluble drug particles provide a convenient dosage form capable of zero-order drug release with release time modulated through number of layers. Copyright © 2018 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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

2016-08-01

3D cellular graphene films with open porosity, high electrical conductivity, and good tensile strength, can be synthesized by a method combining freeze-casting and filtration. The resulting supercapacitors based on 3D porous reduced graphene oxide (RGO) film exhibit extremely high specific power densities and high energy densities. The fabrication process provides an effective means for controlling the pore size, electronic conductivity, and loading mass of the electrode materials, toward devices with high energy-storage performance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Effects of casting and post casting annealing on xylene isomer transport properties of Torlon® 4000T films

KAUST Repository

Chafin, Raymond; Lee, Jong Suk; Koros, William J.

2010-01-01

Procedures for Torlon® 4000T membrane formation were developed to provide attractive and repeatable xylene separation properties. Torlon® 4000T membrane films cast by our method were investigated in terms of thermally induced imidization, molecular weight enhancement, and solvent removal. After development of the Torlon® 4000T casting procedure, pervaporation of a xylene mixture (i.e. 30% para-xylene, 30% meta-xylene, 30% ortho-xylene, and 10% ethylbenzene) was performed in both Torlon® 4000T and post casting annealed Torlon® 4000T films. The xylene pervaporation in annealed Torlon® 4000T film at 200°C gave a permeability of 0.25 Barrer and a selectivity of 3.1 (para/ortho) and 2.1 (para/meta) respectively. A so-called " permeability collapse" reflecting an accelerated reduction in the free volume is consistent with significant temperature-induced changes in the films observed after thermal annealing at 300°C. This conditioning effect is induced by a combination of heat treatment and the presence of the interacting aromatic penetrants. Optical methods were used to verify that the density of annealed samples exposed to xylene for 5 days eventually increased, suggesting that the membrane is originally swollen upon initial xylene exposure, and then relaxes to a more densified, and more discriminating state. © 2010 Elsevier Ltd.
Effects of casting and post casting annealing on xylene isomer transport properties of Torlon® 4000T films

KAUST Repository

Chafin, Raymond

2010-07-01

Procedures for Torlon® 4000T membrane formation were developed to provide attractive and repeatable xylene separation properties. Torlon® 4000T membrane films cast by our method were investigated in terms of thermally induced imidization, molecular weight enhancement, and solvent removal. After development of the Torlon® 4000T casting procedure, pervaporation of a xylene mixture (i.e. 30% para-xylene, 30% meta-xylene, 30% ortho-xylene, and 10% ethylbenzene) was performed in both Torlon® 4000T and post casting annealed Torlon® 4000T films. The xylene pervaporation in annealed Torlon® 4000T film at 200°C gave a permeability of 0.25 Barrer and a selectivity of 3.1 (para/ortho) and 2.1 (para/meta) respectively. A so-called " permeability collapse" reflecting an accelerated reduction in the free volume is consistent with significant temperature-induced changes in the films observed after thermal annealing at 300°C. This conditioning effect is induced by a combination of heat treatment and the presence of the interacting aromatic penetrants. Optical methods were used to verify that the density of annealed samples exposed to xylene for 5 days eventually increased, suggesting that the membrane is originally swollen upon initial xylene exposure, and then relaxes to a more densified, and more discriminating state. © 2010 Elsevier Ltd.
Electroconductive PET/SWNT Films by Solution Casting

Science.gov (United States)

Steinert, Brian W.; Dean, Derrick R.

2008-01-01

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

Science.gov (United States)

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

2015-01-01

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

KAUST Repository

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

2015-01-01

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

KAUST Repository

Kim, Jin Young

2015-07-13

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

Science.gov (United States)

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

2012-12-01

In this paper, thick-film piezoelectric lead zirconate titanate (PZT) ceramic resonators with thicknesses down to tens of micrometers have been fabricated by tape-casting processing. PZT ceramic resonators with composition near the morphotropic phase boundary and with different dopants added were prepared for piezoelectric transducer applications. Material property characterization for these thick-film PZT resonators is essential for device design and applications. For the property characterization, a recently developed normalized electrical impedance spectrum method was used to determine the electromechanical coefficient and the complex piezoelectric, elastic, and dielectric coefficients from the electrical measurement of resonators using thick films. In this work, nine PZT thick-film resonators have been fabricated and characterized, and two different types of resonators, namely thickness longitudinal and transverse modes, were used for material property characterization. The results were compared with those determined by the IEEE standard method, and they agreed well. It was found that depending on the PZT formulation and dopants, the relative permittivities ε(T)(33)/ε(0) measured at 2 kHz for these thick-films are in the range of 1527 to 4829, piezoelectric stress constants (e(33) in the range of 15 to 26 C/m(2), piezoelectric strain constants (d(31)) in the range of -169 × 10(-12) C/N to -314 × 10(-12) C/N, electromechanical coupling coefficients (k(t)) in the range of 0.48 to 0.53, and k(31) in the range of 0.35 to 0.38. The characterization results shows tape-casting processing can be used to fabricate high-quality PZT thick-film resonators, and the extracted material constants can be used to for device design and application.
Comparison of directly compressed vitamin B12 tablets prepared from micronized rotary-spun microfibers and cast films.

Science.gov (United States)

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

2015-01-01

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

Science.gov (United States)

Jiang, Wenming; Fan, Zitian

2018-03-01

Lost foam casting (LFC) is a green precision casting process categorized as a near net forming technology. Yet, despite its popularity, it still suffers from some technological problems, such as poor filling ability of the castings, coarse and non-dense microstructure, low mechanical properties for the Al and Mg LFC processes, and defective carburization for the low carbon steel LFC process. These drawbacks restrict the development and widespread application of the LFC process. To solve these problems, the present study developed several novel LFC technologies, namely, LFC technologies under vacuum and low pressure, vibration solidification, and pressure solidification conditions; expendable shell casting technology; and preparation technology of bimetallic castings based on the LFC process. The results showed that the LFC under vacuum and low pressure evidently improved the filling ability and solved the oxidization problem of the alloys, which is suitable for producing complex and thinwall castings. The vibration and pressure solidifications increased the compactness of the castings and refined the microstructure, significantly improving the mechanical properties of the castings. The expendable shell casting technology could solve the pore, carburization, and inclusion defects of the traditional LFC method, obtaining castings with acceptable surface quality. Moreover, the Al/Mg and Al/Al bimetallic castings with acceptable metallurgical bonding were successfully fabricated using the LFC process. These proposed novel LFC technologies can solve the current technological issues and promote the technological progress of the LFC process.
Crosslinked superhydrophobic films fabricated by simply casting poly(methyl methacrylate-butyl acrylate-hydroxyethyl methacrylate)-b-poly(perfluorohexylethyl methacrylate) solution

Science.gov (United States)

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

2015-06-01

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

Science.gov (United States)

Kohiki, Shigemi; Nara, Koichiro; Mitome, Masanori; Tsuya, Daiju

2014-10-22

An oleic acid-coated Fe2.7Co0.3O4 nanocrystal (NC) self-assembled film was fabricated via drop casting of colloidal particles onto a three-terminal electrode/MgO substrate. The film exhibited a large coercivity (1620 Oe) and bifurcation of the zero-field-cooled and field-cooled magnetizations at 300 K. At 10 K, the film exhibited both a Coulomb blockade due to single electron charging as well as a magnetoresistance of ∼-80% due to spin-dependent electron tunneling. At 300 K, the film also showed a magnetoresistance of ∼-80% due to hopping of spin-polarized electrons. Enhanced magnetic coupling between adjacent NCs and the large coercivity resulted in a large spin-polarized current flow even at 300 K.
Growth directions of C8-BTBT thin films during drop-casting

Science.gov (United States)

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

2016-02-01

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

International Nuclear Information System (INIS)

Del Gaudio, Costantino; Ercolani, Enrico; Nanni, Francesca; Bianco, Alessandra

2011-01-01

Research highlights: → PHBV, PCL and blends were processed in form of solvent cast films and e-spun mats. → A clear phase separation was observed for cast films when blended in equal amount. → E-spun blends were comprised of uniform and defect-free randomly arranged fibers. → DSC and XRD analyses demonstrated the immiscibility of PHBV and PCL. → Rearrangement of e-spun fibers and neckings, after axial test, were observed. - Abstract: Poly(ε-caprolactone) (PCL) and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) were blended in different ratio, e.g. 30/70, 50/50 and 70/30 (w/w), by means of solvent casting or electrospinning. Microstructure, thermal and mechanical properties of cast films and non-woven mats were investigated by means of scanning electron microscopy (SEM), X-ray diffraction analysis (XRD), differential scanning calorimetry (DSC), and uniaxial tensile test. The microstructure of PHBV/PCL solvent cast films (thickness 65-100 μm) was strictly dependent on the composition of the blend, a clean phase separation was observed for the 50/50 (w/w) sample. All electrospun PHBV/PCL blends (thickness 350-800 μm) were characterised by uniform and homogenous fibers, the average size was about 3 μm. Both techniques led to polymeric blends comprised of separate crystalline domains associated to an amorphous interdisperse phase. It has also been demonstrated that electrospun PHBV/PCL blends showed a lower segregation degree among the crystalline domains. Solvent cast blends were characterised by superior mechanical properties in terms of tensile modulus and tensile strength compared to electrospun ones. Fractured electrospun blends showed an overall fiber rearrangement in the direction of the applied load, eventually highlighting multiple necking regions along the fibers.
Non-monotonic piezoresistive behaviour of graphene nanoplatelet (GNP-polymer composite flexible films prepared by solvent casting

Directory of Open Access Journals (Sweden)

S. Makireddi

2017-07-01

Full Text Available Graphene-polymer nanocomposite films show good piezoresistive behaviour and it is reported that the sensitivity increases either with the increased sheet resistance or decreased number density of the graphene fillers. A little is known about this behaviour near the percolation region. In this study, graphene nanoplatelet (GNP/poly (methyl methacrylate (PMMA flexible films are fabricated via solution casting process at varying weight percent of GNP. Electrical and piezoresistive behaviour of these films is studied as a function of GNP concentration. Piezoresistive strain sensitivity of the films is measured by affixing the film to an aluminium specimen which is subjected to monotonic uniaxial tensile load. The change in resistance of the film with strain is monitored using a four probe. An electrical percolation threshold at 3 weight percent of GNP is observed. We report non-monotonic piezoresistive behaviour of these films as a function GNP concentration. We observe an increase in gauge factor (GF with unstrained resistance of the films up to a critical resistance corresponding to percolation threshold. Beyond this limit the GF decreases with unstrained resistance.
Developing technological process of obtaining giality casts

Directory of Open Access Journals (Sweden)

A. Issagulov

2014-10-01

Full Text Available The article considers the process of manufacturing castings using sand-resin forms and alloying furnace. Were the optimal technological parameters of manufacturing shell molds for the manufacture of castings of heating equipment. Using the same upon receipt of castings by casting in shell molds furnace alloying and deoxidation of the metal will provide consumers with quality products and have a positive impact on the economy in general engineering.
Radiography of Co-60 in the lead cube castings

International Nuclear Information System (INIS)

Djoli Soembogo; Harun Al Rasyid R; Namad Sianta

2016-01-01

Radiography Co-60 on Carbon steel or Stainless steel has been widely applied, but for metal Lead has not yet been applied and has not yet widely known. Lead has a greater density than Carbon steel or Stainless steel and could muffle gamma radiation so it takes a longer exposure time. The result of its film radiography are also not as good as compared to radiography applications on carbon steel or Stainless steel. The study also applied digital radiography using isotope Co-60 sources and used Epson V700 scanner positive film for digitization results of conventional radiographic films. These radiographs using film AGFA D7 to get the contrast medium, medium sensitivity and good image quality. The purpose of radiography Co-60 on the cube castings Lead is to find indications of defective castings cube Lead and digitizing the results using conventional radiographic film with a positive film media scanner to process the data transfer and storage of digital data. Radiographic testing has been carried out using the isotope Co-60 on metal castings Lead with a single thickness of a single shadow method using positive film scanner media and isotope Co-60 with disabilities observation parameter Lead metal castings on radiographic film. Co-60 radiation time exposure is 3,500 hours for the thickness of the metal cube castings Lead 100 mm with the activity of 29 Ci and perpendicular SFD of 840 mm. Radiographic testing on metal cube castings Lead by the method of a single thickness of single image defects produce a parameter indicative for a cube of metal castings Lead of porosity level 2. The density mean of radiographic film was 2.051 and 2.046 for 5 minutes in a developer solution. The result of scanning positive film is in the form of digital radiography which allows for the transfer of digital data or computerized storage of digital data. This status is still within limits acceptable under the standards referred. (author)
Optimization of the investment casting process

Directory of Open Access Journals (Sweden)

M. Martinez-Hernandez

2012-04-01

Full Text Available Rapid prototyping is an important technique for manufacturing. This work refers to the manufacture of hollow patterns made of polymeric materials by rapid prototyping technologies for its use in the preparation of ceramic molds in the investment casting process. This work is focused on the development of a process for manufacturing patterns different from those that currently exist due to its hollow interior design, allowing its direct use in the fabrication of ceramic molds; avoiding cracking and fracture during the investment casting process, which is an important process for the foundry industry.
Strong composite films with layered structures prepared by casting silk fibroin-graphene oxide hydrogels

Science.gov (United States)

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

2013-04-01

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

Science.gov (United States)

Yang, Jie; Xiong, Liu; Li, Man; Sun, Qingjie

2018-06-20

The pursuit of sustainable functional materials requires the development of materials based on renewable resources and efficient fabrication methods. Here, we first fabricated chitosan-sodium phytate films via one-step-stripping and layer-by-layer-casting technologies. The proposed film-fabrication methods are general, facile, environmentally benign, cost-effective, and easy to scale up. The resultant one-step-stripped film was thin (9 ± 1 μm), soft, transparent, and strong, whereas the thickness of the layer-by-layer-cast film was 70 ± 3 μm. FTIR analysis of the films indicated the formation of interactions between the phosphoric groups in sodium phytate and the amino groups in chitosan. More importantly, the water-vapor-permeability values of the one-step-stripped and cast films were 4-5 orders of magnitude lower than chitosan films reported before. Layer-by-layer-cast films in particular exhibited high tensile strength (49.21 ± 1.12 MPa) and were more than three times stronger than other polyelectrolyte multilayer films. Both types of films remained stable in an acidic environment. Furthermore, the layer-by-layer-assembled films presented greater antimicrobial activity than the stripped films. The developed chitosan-sodium phytate films can enhance several biomedical and environmental applications, such as packaging, drug delivery, diagnostics, microfluidics, and biosensing.

Effect of medium on friction and wear properties of compacted graphite cast iron processed by biomimetic coupling laser remelting process

International Nuclear Information System (INIS)

Guo Qingchun; Zhou Hong; Wang Chengtao; Zhang Wei; Lin Pengyu; Sun Na; Ren Luquan

2009-01-01

Stimulated by the cuticles of soil animals, an attempt to improve the wear resistance of compact graphite cast iron (CGI) with biomimetic units on the surface was made by using a biomimetic coupled laser remelting process in air and various thicknesses water film, respectively. The microstructures of biomimetic units were examined by scanning electron microscope and X-ray diffraction was used to describe the microstructure and identify the phases in the melted zone. Microhardness was measured and the wear behaviors of biomimetic specimens as functions of different mediums as well as various water film thicknesses were investigated under dry sliding condition, respectively. The results indicated that the microstructure zones in the biomimetic specimens processed with water film are refined compared with that processed in air and had better wear resistance increased by 60%, the microhardness of biomimetic units has been improved significantly. The application of water film provided finer microstructures and much more regular grain shape in biomimetic units, which played a key role in improving the friction properties and wear resistance of CGI.
Effect of medium on friction and wear properties of compacted graphite cast iron processed by biomimetic coupling laser remelting process

Science.gov (United States)

Guo, Qing-chun; Zhou, Hong; Wang, Cheng-tao; Zhang, Wei; Lin, Peng-yu; Sun, Na; Ren, Luquan

2009-04-01

Stimulated by the cuticles of soil animals, an attempt to improve the wear resistance of compact graphite cast iron (CGI) with biomimetic units on the surface was made by using a biomimetic coupled laser remelting process in air and various thicknesses water film, respectively. The microstructures of biomimetic units were examined by scanning electron microscope and X-ray diffraction was used to describe the microstructure and identify the phases in the melted zone. Microhardness was measured and the wear behaviors of biomimetic specimens as functions of different mediums as well as various water film thicknesses were investigated under dry sliding condition, respectively. The results indicated that the microstructure zones in the biomimetic specimens processed with water film are refined compared with that processed in air and had better wear resistance increased by 60%, the microhardness of biomimetic units has been improved significantly. The application of water film provided finer microstructures and much more regular grain shape in biomimetic units, which played a key role in improving the friction properties and wear resistance of CGI.
Mercuric iodide composite films using polyamide, polycarbonate and polystyrene fabricated by casting

International Nuclear Information System (INIS)

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

2010-01-01

Mercuric iodide (HgI 2 ) composite films were obtained by using the casting technique. Insulator polymers such as polyamide, polycarbonate and polystyrene were mixed to HgI 2 crystallites forming a final sub-millimeter thick self-standing film. Fabrication temperature varied from 10 to 100 o C, and total fabrication time reached at most 5 min. The larger the fabrication temperature, the thinner the film and the smaller its electrical resistivity. Electrical characterization was performed in the dark, under UV illumination and under mammographic X-ray exposure. The final properties of the films are discussed and related to fabrication conditions. The optimized composite film might be a better candidate for use as X-ray detector for medical imaging, in place of the single HgI 2 crystalline device.
Relating hydrogen-bonding interactions with the phase behavior of naproxen/PVP K 25 solid dispersions: evaluation of solution-cast and quench-cooled films.

Science.gov (United States)

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

2012-11-05

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.
Structure of zone-cast HBC-C12H25 films

DEFF Research Database (Denmark)

Breiby, Dag Werner; Bunk, Oliver; Pisula, W.

2005-01-01

The structure of a thin zone-cast film of the hexa-n-dodecyl-substituted hexa-peri-benzocoronene (HBC) has been investigated using grazing incidence X-ray diffraction. A model with an orthorhombic unit cell containing two molecules accounts well for the observations. The molecules are arranged...... in a "herringbone" structure resembling the packing observed for unsubstituted HBC. The molecular disk planes are oriented perpendicularly to the substrate, rotated by approximately 39 degrees about the film normal. The relatively long side chains of dodecyl were found to be in an ordered interdigitated state....... The aliphatic side chains and the aromatic HBC-cores segregate to form regular vertical domains spanning the film thickness. For in-plane rocking scans a discrete orientation distribution is observed with peaks at regular angle intervals. We interpret this as a grain boundary effect induced by alkyl chain...
Properties of cast films made of chayote (Sechium edule Sw.) tuber starch reinforced with cellulose nanocrystals

Science.gov (United States)

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, ...
Numerical modelling of the tilt casting processes of titanium alumindes

OpenAIRE

Wang, Hong

2008-01-01

This research has investigated the modelling and optimisation of the tilt casting process of Titanium Aluminides (TiAl). This study is carried out in parallel with the experimental research undertaken in IRC at the University of Birmingham. They propose to use tilt casting inside a vacuum chamber and attempt to combine this tilt casting process with Induction Skull Melting (ISM). A totally novel process is developing for investment casting, which is suitable for casting gamma TiAl.\\ud \\ud As ...
The effects of casting speed on steel continuous casting process

Energy Technology Data Exchange (ETDEWEB)

Sadat, Mohammad; Honarvar Gheysari, Ali; Sadat, Saeid [Islamic Azad University, Department of Mechanics, Mashhad Branch, Mashhad (Iran, Islamic Republic of)

2011-12-15

A three dimensional simulation of molten steel flow, heat transfer and solidification in mold and ''secondary cooling zone'' of Continuous Casting machine was performed with consideration of standard k-{epsilon} model. For this purpose, computational fluid dynamics software, FLUENT was utilized. From the simulation standpoint, the main distinction between this work and preceding ones is that, the phase change process (solidification) and flow (turbulent in mold section and laminar in secondary cooling zone) have been coupled and solved jointly instead of dividing it into ''transient heat conduction'' and ''steady fluid flow'' that can lead to more realistic simulation. Determining the appropriate boundary conditions in secondary cooling zone is very complicated because of various forms of heat transfer involved, including natural and forced convection and simultaneous radiation heat transfer. The main objective of this work is to have better understanding of heat transfer and solidification in the continuous casting process. Also, effects of casting speed on heat flux and shell thickness and role of radiation in total heat transfer is discussed. (orig.)
A Numerical Simulation of Transport Phenomena During the Horizontal Single Belt Casting Process Using an Inclined Feeding System

Science.gov (United States)

Xu, Mianguang; Isac, Mihaiela; Guthrie, Roderick I. L.

2018-06-01

Horizontal single belt casting (HSBC) has great potential to replace current conventional continuous casting (CCC) processes for sheet metal production, by directly casting 3 to 1 mm sheet for the automobile industry. In the present paper, two-dimensional mathematical models were developed to study transport phenomena, for the case of an inclined wall feeding system for a liquid aluminum wrought alloy (AA6111). Based on the commercial software ANSYS FLUENT 14.5 and user-defined functions, a two-layer turbulence model was used to examine the fluid flow emanating from a slot nozzle set above a water-cooled, high-speed, steel belt. The Volume of Fluid (VOF) method was used to predict the shape of the melt-air interface. A transformed coordinate system ( x', y') was established in order to analyze the fluid flow on the inclined wall of the feeding system. The total pressure gauge gradient ( ∂p total/ ∂x) was used to describe the behavior of the melt film inside the slot nozzle of the head box. The modeling results show that during the melt film falling process, the total gauge pressure varies within the slot nozzle, which can decrease the stability of the falling film. The first impingement between the falling film and the inclined refractory wall of the feeding system gives rise to a local oscillation, and this influences the stability of the melt film moving downwards. At the rear meniscus position between the inclined wall and the moving belt, there is a clear vibration of the air-melt interface, together with a recirculation zone. The weak vibration of the air-melt interface could be induced by the periodic variation of the melt-air interface. Moreover, the formation of tiny air pockets is predicted. Finally, on the inclined wall of the feeding system, a suitable length of the transition area is needed to avoid over-acceleration of the melt film due to the force of gravity.
A Numerical Simulation of Transport Phenomena During the Horizontal Single Belt Casting Process Using an Inclined Feeding System

Science.gov (United States)

Xu, Mianguang; Isac, Mihaiela; Guthrie, Roderick I. L.

2018-03-01

Horizontal single belt casting (HSBC) has great potential to replace current conventional continuous casting (CCC) processes for sheet metal production, by directly casting 3 to 1 mm sheet for the automobile industry. In the present paper, two-dimensional mathematical models were developed to study transport phenomena, for the case of an inclined wall feeding system for a liquid aluminum wrought alloy (AA6111). Based on the commercial software ANSYS FLUENT 14.5 and user-defined functions, a two-layer turbulence model was used to examine the fluid flow emanating from a slot nozzle set above a water-cooled, high-speed, steel belt. The Volume of Fluid (VOF) method was used to predict the shape of the melt-air interface. A transformed coordinate system (x', y') was established in order to analyze the fluid flow on the inclined wall of the feeding system. The total pressure gauge gradient (∂p total/∂x) was used to describe the behavior of the melt film inside the slot nozzle of the head box. The modeling results show that during the melt film falling process, the total gauge pressure varies within the slot nozzle, which can decrease the stability of the falling film. The first impingement between the falling film and the inclined refractory wall of the feeding system gives rise to a local oscillation, and this influences the stability of the melt film moving downwards. At the rear meniscus position between the inclined wall and the moving belt, there is a clear vibration of the air-melt interface, together with a recirculation zone. The weak vibration of the air-melt interface could be induced by the periodic variation of the melt-air interface. Moreover, the formation of tiny air pockets is predicted. Finally, on the inclined wall of the feeding system, a suitable length of the transition area is needed to avoid over-acceleration of the melt film due to the force of gravity.
Espalhamento e secagem de filme de amido-glicerol-fibra preparado por "tape-casting"

Directory of Open Access Journals (Sweden)

Jaqueline Oliveira de Moraes

2014-02-01

Full Text Available O objetivo deste trabalho foi avaliar processos de espalhamento e secagem de filme de amido-glicerol-fibras de celulose, preparado por "tape-casting". O espalhamento da suspensão foi avaliado a 50, 150 e 250 cm min-1, seguido de secagem em estufa com circulação forçada de ar, a 40 ou 70ºC; avaliou-se também o espalhamento da suspensão a 150 cm min-1, seguido da secagem do filme sobre suporte de "tape-casting" a 22ºC e 60% de umidade relativa, com velocidades do ar de 4, 6 e 8 m s-1 no túnel de secagem. Ensaios reológicos mostraram que o espalhamento das suspensões a temperaturas inferiores a 50ºC apresentou módulo de elasticidade superior ao módulo viscoso, em todo o espectro de frequências de oscilação. As microscopias mostraram filmes secos a 40 e 70ºC sem defeitos de formação, e cujas propriedades mecânicas não diferiam. A velocidade de espalhamento e a do ar não modificam o tempo de secagem nem as propriedades dos filmes. O tempo de secagem pode ser reduzido para aproximadamente duas horas, o que é importante para a produção dos filmes em larga escala.
Thickness control and interface quality as functions of slurry formulation and casting speed in side-by-side tape casting

DEFF Research Database (Denmark)

Bulatova, Regina; Jabbari, Mirmasoud; Kaiser, Andreas

2014-01-01

A novel method of co-casting called side-by-side tape casting was developed aiming to form thin functionally graded films with varying properties within a single plane. The standard organic-based recipe was optimized to co-cast slurries into thick graded tapes. Performed numerical simulations...... identified the stable flow beneath the blade with a shear rate profile independent of slurry viscosity as long as the slurry load in the casting tank was low. Thickness and interface shape could be well predicted if the rheological behaviour of slurries is known and the processing parameters are well...
Application of film-casting technique to investigate drug-polymer miscibility in solid dispersion and hot-melt extrudate.

Science.gov (United States)

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

2015-07-01

Determination of drug-polymer miscibility is critical for successful development of solid dispersions. This report details a practical method to predict miscibility and physical stability of drug with various polymers in solid dispersion and, especially, in melt extrudates by applying a film-casting technique. Mixtures of itraconazole (ITZ) with hydroxypropylmethylcellulose phthalate (HPMCP), Kollidon(®) VA 64, Eudragit(®) E PO, and Soluplus(®) were film-casted, exposed to 40°C/75% RH for 1 month and then analyzed using differential scanning calorimetry (DSC), powder X-ray diffractometry, and polarized light microscopy (PLM). ITZ had the highest miscibility with HPMCP, being miscible at drug to polymer ratio of 6:4 (w/w). There was a downward trend of lower miscibility with Soluplus(®) (miscible at 3:7, w/w, and a few microcrystals present at 4:6, w/w), Kollidon(®) VA 64 (2:8, w/w) and Eudragit(®) E PO (casting and hot-melt extrusion (HME) using a twin screw extruder. For ITZ-Soluplus(®) mixtures, HME at 4:6 (w/w) resulted in a single phase, whereas drug crystallization was observed at higher drug load. HME of ITZ-Kollidon(®) VA 64 mixtures also correlated well with the miscibility predicted by film casting. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association.
Radiographic Co-60 in component of heavy equipment casting

International Nuclear Information System (INIS)

Djoli Soembogo, Harun Al Rasyid R dan Namad Sianta

2016-01-01

The application of radiography using isotope Co-60 source has been used on component of heavy equipment such as component of heavy equipment casting. Components of heavy equipment casting made through metal casting of carbon steel. This study tried applying digital radiography are using isotope Co-60 sources and using scanning positive film media of Epson V700 for digitization results of conventional radiographic films. This radiography is using film AGFA D7 and Fuji 100 to obtain a contrast medium, medium sensitivity and image quality is good. The purpose radiographic Co-60 at a component of heavy equipment casting is detecting indications of the shape and type casting defects of component of heavy equipment casting thus fit for use. Radiographic test of Co-60 has been carried out on component of heavy equipment casting with single wall single image method and the results of radiographic films digitization using scanning positive film media of Epson V700 with observation parameters casting defects. Time exposure of Co-60 radiation was 10 and 15 minutes hours for metal castings of carbon steel for thickness 20.00-50.00 mm by using activity 30.05 Ci and the perpendicular distance to the source of the film is 820 mm. Scanner positive film results in the form of digital radiography which allow for the transfer of digital data or digital computerized data storage. Radiographic test results on component of heavy equipment casting with single wall single image method produce the parameter casting defect of component of heavy equipment casting in position of critical area is found shrinkage that should be repaired and in position of safety area is not found defect indication so casting defect of component of heavy equipment casting are not acceptable according to standards referenced. (author)
Controlling coverage of solution cast materials with unfavourable surface interactions

KAUST Repository

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

2014-01-01

Creating uniform coatings of a solution-cast material is of central importance to a broad range of applications. Here, a robust and generic theoretical framework for calculating surface coverage by a solid film of material de-wetting a substrate is presented. Using experimental data from semiconductor thin films as an example, we calculate surface coverage for a wide range of annealing temperatures and film thicknesses. The model generally predicts that for each value of the annealing temperature there is a range of film thicknesses leading to poor surface coverage. The model accurately reproduces solution-cast thin film coverage for organometal halide perovskites, key modern photovoltaic materials, and identifies processing windows for both high and low levels of surface coverage. © 2014 AIP Publishing LLC.
Controlling coverage of solution cast materials with unfavourable surface interactions

KAUST Repository

Burlakov, V. M.

2014-03-03

Creating uniform coatings of a solution-cast material is of central importance to a broad range of applications. Here, a robust and generic theoretical framework for calculating surface coverage by a solid film of material de-wetting a substrate is presented. Using experimental data from semiconductor thin films as an example, we calculate surface coverage for a wide range of annealing temperatures and film thicknesses. The model generally predicts that for each value of the annealing temperature there is a range of film thicknesses leading to poor surface coverage. The model accurately reproduces solution-cast thin film coverage for organometal halide perovskites, key modern photovoltaic materials, and identifies processing windows for both high and low levels of surface coverage. © 2014 AIP Publishing LLC.
Oromucosal film preparations: points to consider for patient centricity and manufacturing processes.

Science.gov (United States)

Krampe, Raphael; Visser, J Carolina; Frijlink, Henderik W; Breitkreutz, Jörg; Woerdenbag, Herman J; Preis, Maren

2016-01-01

According to the European Pharmacopoeia, oromucosal films comprise mucoadhesive buccal films and orodispersible films. Both oral dosage forms receive considerable interest in the recent years as commercially available pharmaceutical products and as small scale personalized extemporaneous preparations. In this review, technological issues such as viscosity of the casting liquid, mechanical properties of the film, upscaling and the stability of the casting solution and produced films will be discussed. Furthermore, patient-related problems like appearance, mucosal irritation, taste, drug load, safety and biopharmaceutics are described. Current knowledge and directions for solutions are summarized. The viscosity of the casting solution is a key factor for producing suitable films. This parameter is amongst others dependent on the polymer and active pharmaceutical ingredient, and the further excipients that are used. For optimal patient compliance, an acceptable taste and palatability are desirable. Safe and inert excipients should be used and appropriate packaging should be provided to produced films. Absorption through the oral mucosa will vary for each active compound, formulation and patient, which gives rise to pharmacokinetic questions. Finally, the European Pharmacopoeia needs to specify methods, requirement and definitions for oromucosal film preparations based on bio-relevant data.
Real-time measurement system for tracking birefringence, weight, thickness, and surface temperature during drying of solution cast coatings and films

Science.gov (United States)

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

2012-02-01

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

Energy Technology Data Exchange (ETDEWEB)

Puthirath, Anand B.; Varma, Sreekanth J.; Jayalekshmi, S., E-mail: jayalekshmi@cusat.ac.in [Division for Research in Advanced Materials, Department of Physics, Cochin University of Science and Technology, Cochin, Kerala 682022 (India); Methattel Raman, Shijeesh [Nanophotonic and Optoelectronic Devices Laboratory, Department of Physics, Cochin University of Science and Technology, Cochin, Kerala 682022 (India)

2016-04-18

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

International Nuclear Information System (INIS)

Park, Sung Kyu; Kim, Yong-Hoon; Han, Jeong-In

2009-01-01

We report all solution-processed high-resolution bottom-contact indium-gallium-zinc-oxide (IGZO) thin film transistors (TFTs) using a simple surface patterning and dip-casting process. High-resolution nanoparticulate Ag source/drain electrodes and a sol-gel processed IGZO semiconductor were deposited by a simple dip-casting along with a photoresist-free, non-relief-pattern lithographic process. The deposited Ag and IGZO solution can be steered into the desired hydrophilic areas by a low surface energy self-assembled monolayer, resulting in source/drain electrodes and semiconducting layer, respectively. The all solution-processed bottom-contact IGZO TFTs including a channel length of 10 μm typically showed a mobility range 0.05-0.2 cm 2 V -1 s -1 with an on/off ratio of more than 10 6 .

The temperature gradient on section of casting in process of primary crystallization of chromium cast iron

Directory of Open Access Journals (Sweden)

A. Studnicki

2008-08-01

Full Text Available The methodology of defining in article was introduced the temperature gradient in process of primary crystallization during cooling the casting from chromium cast iron on basis of measurements of thermal field in test DTA-K3. Insert also the preliminary results of investigations of influence temperature gradient on structure of studied wear resistance chromium cast iron.
Fundamentals of Numerical Modelling of Casting Processes

DEFF Research Database (Denmark)

Hattel, Jesper Henri; Pryds, Nini; Thorborg, Jesper

Fundamentals of Numerical Modelling of Casting Processes comprises a thorough presentation of the basic phenomena that need to be addressed in numerical simulation of casting processes. The main philosophy of the book is to present the topics in view of their physical meaning, whenever possible......, rather than relying strictly on mathematical formalism. The book, aimed both at the researcher and the practicing engineer, as well as the student, is naturally divided into four parts. Part I (Chapters 1-3) introduces the fundamentals of modelling in a 1-dimensional framework. Part II (Chapter 4...
Simulation of ingot casting processes at Deutsche Edelstahlwerke GmbH®

International Nuclear Information System (INIS)

Hartmann, L; Ernst, C; Klung, J-S

2012-01-01

To enhance the quality of tool steels it is necessary to analyse all stages of the production process. During the ingot- or continuous casting processes and the following solidification, material and geometry depending reactions cause defects such as macro segregations or porosities. In former times the trial and error approach, together with the experience and creativity of the steelworks engineers was used to improve the as-cast quality, with a high amount of test procedures and a high demand of research time and costs. Further development in software and algorithms has allowed modern simulation techniques to find their way into industrial steel production and casting-simulations are widely used to achieve an accurate prediction of the ingot quality. To improve the as-cast quality, several ingot casting processes of tool steels were studied at the R and D department of Deutsche Edelstahlwerke GmbH by using the numerical casting simulation software MAGMASOFT ® . In this paper some results extracted from the simulation software are shown and compared to experimental investigations.
Experiments on the Model Testing of the 2nd Phase of Die Casting Process Compared with the Results of Numerical Simulation

Directory of Open Access Journals (Sweden)

Dańko R.

2015-12-01

Full Text Available Experiments of filling the model moulds cavity of various inner shapes inserted in rectangular cavity of the casting die (dimensions: 280 mm (height × 190 mm (width × 10 mm (depth by applying model liquids of various density and viscosity are presented in the paper. Influence of die venting as well as inlet system area and inlet velocity on the volumetric rate of filling of the model liquid - achieved by means of filming the process in the system of a cold-chamber casting die was tested. Experiments compared with the results of simulation performed by means of the calculation module Novacast (Novaflow&Solid for the selected various casting conditions - are also presented in the paper.
Grain refinement of DC cast magnesium alloys with intensive melt shearing

International Nuclear Information System (INIS)

Zuo, Y B; Jiang, B; Zhang, Y; Fan, Z

2012-01-01

A new direct chill (DC) casting process, melt conditioned DC (MC-DC) process, has been developed for the production of high quality billets/slabs of light alloys by application of intensive melt shearing through a rotor-stator high shear device during the DC casting process. The rotor-stator high shear device provides intensive melt shearing to disperse the naturally occurring oxide films, and other inclusions, while creating a microscopic flow pattern to homogenize the temperature and composition fields in the sump. In this paper, we report the grain refining effect of intensive melt shearing in the MC-DC casting processing. Experimental results on DC casting of Mg-alloys with and without intensive melt shearing have demonstrated that the MC-DC casting process can produce magnesium alloy billets with significantly refined microstructure. Such grain refinement in the MC-DC casting process can be attributed to enhanced heterogeneous nucleation by dispersed naturally occurring oxide particles, increased nuclei survival rate in uniform temperature and compositional fields in the sump, and potential contribution from dendrite arm fragmentation.
Integrated Modeling of Process, Structures and Performance in Cast Parts

DEFF Research Database (Denmark)

Kotas, Petr

This thesis deals with numerical simulations of gravity sand casting processes for the production of large steel parts. The entire manufacturing process is numerically modeled and evaluated, taking into consideration mould filling, solidification, solid state cooling and the subsequent stress build...... and to defects occurrence. In other words, it is desired to eliminate all of the potential casting defects and at the same time to maximize the casting yield. The numerical optimization algorithm then takes these objectives and searches for a set of the investigated process, design or material parameters e.......g. chill design, riser design, gating system design, etc., which would satisfy these objectives the most. The first step in the numerical casting process simulation is to analyze mould filling where the emphasis is put on the gating system design. There are still a lot of foundry specialists who ignore...
Application of complex inoculants in improving the process-ability of grey cast iron for cylinder blocks

Directory of Open Access Journals (Sweden)

LIU Wei-ming

2006-05-01

Full Text Available Effect of several complex inoculants on mechanical properties, process-ability and sensibility of grey cast iron used in cylinder block were investigated. The experimental results showed that the grey cast iron treated with 60%FeSi75+40%RE complex inoculants has tensile strength consistently at about 295 MPa along with good hardness and improved metallurgy quality. While the grey cast iron inoculated with 20%FeSi75+80%Sr compound inoculants has the best process-ability, the lowest cross-section sensibility and the least microhardness difference. The wear amount of the drill increases correspondingly with the increase of the microhardness difference of matrix structure, indicating the great effect of homogeneousness of matrix structure in the grey cast iron on the machinability of the grey cast iron.
Drug-printing by flexographic printing technology--a new manufacturing process for orodispersible films.

Science.gov (United States)

Janssen, Eva Maria; Schliephacke, Ralf; Breitenbach, Armin; Breitkreutz, Jörg

2013-01-30

Orodispersible films (ODFs) are intended to disintegrate within seconds when placed onto the tongue. The common way of manufacturing is the solvent casting method. Flexographic printing on drug-free ODFs is introduced as a highly flexible and cost-effective alternative manufacturing method in this study. Rasagiline mesylate and tadalafil were used as model drugs. Printing of rasagiline solutions and tadalafil suspensions was feasible. Up to four printing cycles were performed. The possibility to employ several printing cycles enables a continuous, highly flexible manufacturing process, for example for individualised medicine. The obtained ODFs were characterised regarding their mechanical properties, their disintegration time, API crystallinity and homogeneity. Rasagiline mesylate did not recrystallise after the printing process. Relevant film properties were not affected by printing. Results were comparable to the results of ODFs manufactured with the common solvent casting technique, but the APIs are less stressed through mixing, solvent evaporation and heat. Further, loss of material due to cutting jumbo and daughter rolls can be reduced. Therefore, a versatile new manufacturing technology particularly for processing high-potent low-dose or heat sensitive drugs is introduced in this study. Copyright © 2012 Elsevier B.V. All rights reserved.
Geometrical modulus of a casting and its influence on solidification process

Directory of Open Access Journals (Sweden)

F. Havlicek

2011-10-01

Full Text Available Object: The work analyses the importance of the known criterion for evaluating the controlled solidification of castings, so called geometrical modulus defined by N. Chvorinov as the first one. Geometrical modulus influences the solidification process. The modulus has such specificity that during the process of casting formation it is not a constant but its initial value decreases with the solidification progress because the remaining melt volume can decrease faster than its cooling surface.Methodology: The modulus is determined by a simple calculation from the ratio of the casting volume after pouring the metal in the mould to the cooled mould surface. The solidified metal volume and the cooled surface too are changed during solidification. That calculation is much more complicated. Results were checked up experimentally by measuring the temperatures in the cross-section of heavy steel castings during cooling them.Results: The given experimental results have completed the original theoretical calculations by Chvorinov and recent researches done with use of numerical calculations. The contribution explains how the geometrical modulus together with the thermal process in the casting causes the higher solidification rate in the axial part of the casting cross-section and shortening of solidification time. Practical implications: Change of the geometrical modulus negatively affects the casting internal quality. Melt feeding by capillary filtration in the dendritic network in the casting central part decreases and in such a way the shrinkage porosity volume increases. State of stress character in the casting is changed too and it increases.
[Corrosion property and oxide film of dental casting alloys before and after porcelain firing].

Science.gov (United States)

Ma, Qian; Wu, Feng-ming

2011-03-01

To evaluate the types and compositions of oxide films formed during porcelain-fused-to-metal (PFM) firing on three kinds of dental casting alloys, and to investigate the corrosion property of these alloys in Dulbecco's modification of Eagle's medium (DMEM) cell culture fluid, before and after PFM firing. Specimens of three dental casting alloys (Ni-Cr, Co-Cr and Ni-Ti) before and after PFM firing were prepared, and were immersed in DMEM cell culture fluid. After 30 days, the type and concentration of released metal ions were measured using inductively coupled plasma atomic emission spectroscopy (ICP-AES). X-ray photoelectron spectroscopy (XPS) and scanning electron microscope (SEM) were used for analysis of oxide film on the alloys. One way-ANOVA was adopted in data analysis. The total amount of metal ions released from the three dental alloys was found to be highest in Ni-Cr alloy [(2.829 ± 0.694) mg/L], followed by Co-Cr [(2.120 ± 0.418) mg/L] and Ni-Ti alloy [(1.211 ± 0.101) mg/L]. The amount of Ni ions released from Ni-Cr alloys [(1.531 ± 0.392) mg/L] was higher than that from Ni-Ti alloys [(0.830 ± 0.052) mg/L]. The amount of Cr, Mo ions released from Co-Cr alloy [Cr: (0.048 ± 0.011) mg/L, Mo: (1.562 ± 0.333) mg/L] was higher than that from Ni-Cr alloy [Cr: (0.034 ± 0.002) mg/L, Mo: (1.264 ± 0.302) mg/L] and Ni-Ti alloy [Cr: (0.013 ± 0.006) mg/L, Mo: (0.151 ± 0.026) mg/L] (P < 0.05). After PFM firing, the total amount of metal irons released from the three dental alloys decreased [Ni-Cr: (0.861 ± 0.054) mg/L, Co-Cr: (0.695 ± 0.327) mg/L, Ni-Ti: (0.892 ± 0.115) mg/L] (P < 0.05). In addition, XPS showed increase of Cr(2)O(3) and Mo-Ni oxide on the surface of all the alloys after PFM firing. The amount of ions released from Ni-Cr alloy was the highest among the three dental casting alloys, this means Ni-Cr alloy is prone to corrode. The PFM firing process changed the alloys' surface composition. Increased Ni, Cr and Mo were found in oxide film, and
Fabrication of hierarchically structured superhydrophobic PDMS surfaces by Cu and CuO casting

Science.gov (United States)

Migliaccio, Christopher P.; Lazarus, Nathan

2015-10-01

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

Science.gov (United States)

Steiner, Denise; Finke, Jan Henrik; Kwade, Arno

2016-09-25

Orodispersible films possess a great potential as a versatile platform for nanoparticle-loaded oral dosage forms. In this case, poorly water-soluble organic materials were ground in a stirred media mill and embedded into a polymer matrix. The aim of this study was the shortening of this manufacturing process by the integration of several process steps into a stirred media mill without facing disadvantages regarding the film quality. Furthermore, this process integration is time conserving due to the high stress intensities provided in the mill and applicable for high solids contents and high suspension viscosities. Two organic materials, the model compound Anthraquinone and the active pharmaceutical ingredient Naproxen were investigated in this study. Besides the impact of the film processing on the crystallinity of the particles in the orodispersible film, a particle load of up to 50% was investigated with the new developed processing route. Additionally, a disintegration test was developed, combining an appropriate amount of saliva substitute and a clear endpoint determination. In summary, high nanoparticle loads in orodispersible films with good particle size preservation after film redispersion in water as well as a manufacturing of the film casting mass within a few minutes in a stirred media mill was achieved. Copyright © 2016 Elsevier B.V. All rights reserved.
Ductile cast iron obtaining by Inmold method with use of LOST FOAM process

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T. Pacyniak

2010-01-01

Full Text Available The possibility of manufacturing of ductile cast iron castings by Inmold method with use of LOST FOAM process was presented in this work. The spheroidization was carried out by magnesium master alloy in amounts of 1% casting mass. Nodulizer was located in the reactive chamber in the gating system made of foamed polystyrene. Pretests showed, that there are technical possibilities of manufacturing of casts from ductile cast iron in the LOST FOAM process with use of spheroidization in mould.
Diclofenac sodium ion exchange resin complex loaded melt cast films for sustained release ocular delivery.

Science.gov (United States)

Adelli, Goutham R; Balguri, Sai Prachetan; Bhagav, Prakash; Raman, Vijayasankar; Majumdar, Soumyajit

2017-11-01

The goal of the present study is to develop polymeric matrix films loaded with a combination of free diclofenac sodium (DFS free ) and DFS:Ion exchange resin complexes (DFS:IR) for immediate and sustained release profiles, respectively. Effect of ratio of DFS and IR on the DFS:IR complexation efficiency was studied using batch processing. DFS:IR complex, DFS free , or a combination of DFS free + DFS:IR loaded matrix films were prepared by melt-cast technology. DFS content was 20% w/w in these matrix films. In vitro transcorneal permeability from the film formulations were compared against DFS solution, using a side-by-side diffusion apparatus, over a 6 h period. Ocular disposition of DFS from the solution, films and corresponding suspensions were evaluated in conscious New Zealand albino rabbits, 4 h and 8 h post-topical administration. All in vivo studies were carried out as per the University of Mississippi IACUC approved protocol. Complexation efficiency of DFS:IR was found to be 99% with a 1:1 ratio of DFS:IR. DFS release from DFS:IR suspension and the film were best-fit to a Higuchi model. In vitro transcorneal flux with the DFS free + DFS:IR (1:1) (1 + 1) was twice that of only DFS:IR (1:1) film. In vivo, DFS solution and DFS:IR (1:1) suspension formulations were not able to maintain therapeutic DFS levels in the aqueous humor (AH). Both DFS free and DFS free + DFS:IR (1:1) (3 + 1) loaded matrix films were able to achieve and maintain high DFS concentrations in the AH, but elimination of DFS from the ocular tissues was much faster with the DFS free formulation. DFS free + DFS:IR combination loaded matrix films were able to deliver and maintain therapeutic DFS concentrations in the anterior ocular chamber for up to 8 h. Thus, free drug/IR complex loaded matrix films could be a potential topical ocular delivery platform for achieving immediate and sustained release characteristics.
Effects of thermomechanical processing on titanium aluminide strip cast by the melt overflow process

Energy Technology Data Exchange (ETDEWEB)

Gaspar, T.A. (Ribbon Technology Corporation, PO Box 30758, Columbus, OH 43230 (United States)); Hackman, L.E. (Ribbon Technology Corporation, PO Box 30758, Columbus, OH 43230 (United States)); Batawi, E. (Sulzer-Innotec, Division 1511, PO Box 65, Winterthur 8404 (Switzerland)); Peters, J.A. (Sulzer-Innotec, Division 1511, PO Box 65, Winterthur 8404 (Switzerland))

1994-05-01

The objective of this research project was to investigate the feasibility of producing titanium aluminide foils from direct cast strip using ribbon technology''s plasma melt overflow process. Niobium-modified Ti[sub 3]Al alloys were melted in a cold copper crucible using a transferred plasma arc and then direct cast into strip on a rotating chill roll.Samples cut from the as-cast Ti[sub 3]Al-Nb ([alpha][sub 2]) titanium aluminide strip were encapsulated into a pack. The packs were heated to the rolling temperature and then hot rolled at low strain rates. Foils 70 [mu]m (0.003 in) thick, having a uniform [alpha][sub 2]-B2 microstructure with oxygen contents as low as 900 wt.ppm were obtained after pack rolling. The strips and foils were characterized in terms of microstructure and chemical composition in the as-received, heat-treated and pack-rolled conditions.The results indicated that it was technically feasible to produce foils from direct cast titanium aluminide strip using pack-rolling technology. The advantage of this technology lies in its cost-effectiveness, since the relatively low cost direct-cast titanium aluminide strip was thermomechanically processed into foil with the desired microstructure without any intermediate processing steps. ((orig.))
Manufacturing of aluminum composite material using stir casting process

International Nuclear Information System (INIS)

Jokhio, M.H.; Panhwar, M.I.; Unar, M.A.

2011-01-01

Manufacturing of aluminum alloy based casting composite materials via stir casting is one of the prominent and economical route for development and processing of metal matrix composites materials. Properties of these materials depend upon many processing parameters and selection of matrix and reinforcements. Literature reveals that most of the researchers are using 2, 6 and 7 xxx aluminum matrix reinforced with SiC particles for high strength properties whereas, insufficient information is available on reinforcement of 'AI/sub 2/O/sub 3/' particles in 7 xxx aluminum matrix. The 7 xxx series aluminum matrix usually contains Cu-Zn-Mg; Therefore, the present research was conducted to investigate the effect of elemental metal such as Cu-Zn-Mg in aluminum matrix on mechanical properties of stir casting of aluminum composite materials reinforced with alpha 'AI/sub 2/O/sub 3/' particles using simple foundry melting alloying and casting route. The age hardening treatments were also applied to study the aging response of the aluminum matrix on strength, ductility and hardness. The experimental results indicate that aluminum matrix cast composite can be manufactured via conventional foundry method giving very good responses to the strength and ductility up to 10% 'AI/sub 2/O/sub 3/' particles reinforced in aluminum matrix. (author)
Manufacturing of Aluminum Composite Material Using Stir Casting Process

Directory of Open Access Journals (Sweden)

Muhammad Hayat Jokhio

2011-01-01

Full Text Available Manufacturing of aluminum alloy based casting composite materials via stir casting is one of the prominent and economical route for development and processing of metal matrix composites materials. Properties of these materials depend upon many processing parameters and selection of matrix and reinforcements. Literature reveals that most of the researchers are using 2, 6 and 7xxx aluminum matrix reinforced with SiC particles for high strength properties whereas, insufficient information is available on reinforcement of \\"Al2O3\\" particles in 7xxx aluminum matrix. The 7xxx series aluminum matrix usually contains Cu-Zn-Mg. Therefore, the present research was conducted to investigate the effect of elemental metal such as Cu-Zn-Mg in aluminum matrix on mechanical properties of stir casting of aluminum composite materials reinforced with alpha \\"Al2O3\\" particles using simple foundry melting alloying and casting route. The age hardening treatments were also applied to study the aging response of the aluminum matrix on strength, ductility and hardness. The experimental results indicate that aluminum matrix cast composite can be manufactured via conventional foundry method giving very good responses to the strength and ductility up to 10% \\"Al2O3\\" particles reinforced in aluminum matrix.
Surface hardening of two cast irons by friction stir processing

International Nuclear Information System (INIS)

Fujii, Hidetoshi; Kikuchi, Toshifumi; Nogi, Kiyoshi; Yamaguchi, Yasufumi; Kiguchi, Shoji

2009-01-01

The Friction Stir Processing (FSP) was applied to the surface hardening of cast irons. Flake graphite cast iron (FC300) and nodular graphite cast iron (FCD700) were used to investigate the validity of this method. The matrices of the FC300 and FC700 cast irons are pearlite. The rotary tool is a 25mm diameter cylindrical tool, and the travelling speed was varied between 50 and 150mm/min in order to control the heat input at the constant rotation speed of 900rpm. As a result, it has been clarified that a Vickers hardness of about 700HV is obtained for both cast irons. It is considered that a very fine martensite structure is formed because the FSP generates the heat very locally, and a very high cooling rate is constantly obtained. When a tool without an umbo (probe) is used, the domain in which graphite is crushed and striated is minimized. This leads to obtaining a much harder sample. The hardness change depends on the size of the martensite, which can be controlled by the process conditions, such as the tool traveling speed and the load. Based on these results, it was clarified that the FSP has many advantages for cast irons, such as a higher hardness and lower distortion. As a result, no post surface heat treatment and no post machining are required to obtain the required hardness, while these processes are generally required when using the traditional methods.
Toxicological evaluation of natural rubber films from vulcanized latex by the conventional process and the alternative process with ionizing radiation

International Nuclear Information System (INIS)

Campos, Vania Elisabeth

1997-01-01

The industrial vulcanization of natural rubber latex (NRL) is made all over the world by conventional process using sulphur and heat but it can be made by an alternative process using ionizing radiation. In this research the NRL was tested by 13 physical, chemical and mechanical assays which showed its good quality. It was done a preliminary study of the toxicological properties of 4 natural rubber films obtained by casting process of NRL: one non vulcanized, other vulcanized by the conventional process and two vulcanized by the alternative process. In the alternative process the films were obtained by irradiation of NRL by gamma rays from the 60 Co source at 250 kGy in the absence of sensitizer and irradiated NRL at 12 kGy in the presence of 4ph r of n-butyl acrylate / 0.2 phr of KOH. These vulcanization doses were determined from broken tensile strength. In the conventional process, sulphur vulcanized NRL was made using a classical composition. Another film was made with non vulcanized NRL. The preliminary evaluation of the toxicological properties was made from in vitro cytotoxicity and in vivo systemic toxicity assays. The LBN films vulcanized by the alternative process have less cytotoxicity than the NRL film vulcanized by the conventional process. The sensitized vulcanized films by gamma rays and non vulcanized films showed similar cytotoxicity while the vulcanized films without sensitizer showed a slight lower cytotoxicity. The non vulcanized NRL film and the NRL films vulcanized by the alternative process did not show toxic effects int he 72 hours period of the systemic toxicity assay. However the NRL film vulcanized with sulphur induced effects like allaying and motor in coordination on the animals treated with an oil extract at the fourth hour and recovering after that. The alternative process promoted lower toxic effects than conventional process because there was no toxic substances present. (author)
Quality and Safety Assurance of Iron Casts and Manufacturing Processes

OpenAIRE

Kukla S.

2016-01-01

The scope of this work focuses on the aspects of quality and safety assurance of the iron cast manufacturing processes. Special attention was given to the processes of quality control and after-machining of iron casts manufactured on automatic foundry lines. Due to low level of automation and huge work intensity at this stage of the process, a model area was established which underwent reorganization in accordance with the assumptions of the World Class Manufacturing (WCM). An analysis of wor...

Synergistic Impact of Solvent and Polymer Additives on the Film Formation of Small Molecule Blend Films for Bulk Heterojunction Solar Cells

KAUST Repository

McDowell, Caitlin

2015-07-14

The addition of polystyrene (PS), a typical insulator, is empirically shown to increase the power conversion efficiencies (PCEs) of a solution-deposited bulk heterojunction (BHJ) molecular blend film used in solar cell fabrication: p-DTS(FBTTh2)2/PC71BM. The performance is further improved by small quantities of diiodooctane (DIO), an established solvent additive. In this study, how the addition of PS and DIO affects the film formation of this bulk heterojunction blend film are probed via in situ monitoring of absorbance, thickness, and crystallinity. PS and DIO additives are shown to promote donor crystallite formation on different time scales and through different mechanisms. PS-containing films retain chlorobenzene solvent, extending evaporation time and promoting phase separation earlier in the casting process. This extended time is insufficient to attain the morphology for optimal PCE results before the film sets. Here is where the presence of DIO comes into play: its low vapor pressure further extends the time scale of film evolution and allows for crystalline rearrangement of the donor phase long after casting, ultimately leading to the best BHJ organization. In situ measurement shows that polystyrene (PS) and diiodooctane (DIO) additives promote donor crystallite formation synergistically, on different time scales, and through different mechanisms. PS-rich films retain solvent, promoting phase separation early in the casting process. Meanwhile, the low vapor pressure of DIO extends the time scale of film evolution and allows for crystalline rearrangement of the donor phase after casting. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Characterization of Jatropha curcas L. Protein Cast Films with respect to Packaging Relevant Properties

Directory of Open Access Journals (Sweden)

Gabriele Gofferje

2015-01-01

Full Text Available There is increasing research ongoing towards the substitution of petrochemical based plastics by more sustainable raw materials, especially in the field of bioplastics. Proteins of different types such as whey, casein, gelatine, or zein show potential beyond the food and feed industry as, for instance, the application in packaging. Protein based coatings provide different packaging relevant properties such as barrier against permanent gases, certain water vapour barrier, and mechanical resistance. The aim of this study was to explore the potential for packaging applications of proteins from Jatropha curcas L. and to compare the performance with literature data on cast films from whey protein isolate. As a by-product from oil extraction, high amounts of Jatropha meal are obtained requiring a concept for its sustainable utilization. Jatropha seed cake includes up to 40% (w/w of protein which is currently not utilized. The present study provides new data on the potential of Jatropha protein for packaging applications. It was shown that Jatropha protein cast films show suitable barrier and mechanical properties depending on the extraction and purification method as well as on the plasticiser content. Based on these findings Jatropha proteins own potential to be utilized as coating material for food packaging applications.
Modelling of shrinkage cavity defects during the wheel and belt casting process

International Nuclear Information System (INIS)

Dablement, S; Mortensen, D; Fjaer, H; Lee, M; Grandfield, J; Savage, G; Nguyen, V

2012-01-01

Properzi continuous casting is a wheel and belt casting process used for producing aluminium wire rod which is essential to the making of electrical cables and over head lines. One of the main concerns of Properzi process users is to ensure good quality of the final product and to avoid cast defects especially the presence of shrinkage cavity. Numerical models developed with the Alsim software, which allows an automatic calculation of gap dependent heat transfer coefficients at the metal-mould interface due to thermal deformation, are used in order to get a better understanding on the shrinkage cavity formation. Models show the effect of process parameters on the cavity defect development and provide initial guidance for users in order to avoid this kind of casting defect.
Film processing

International Nuclear Information System (INIS)

Abdul Nassir Ibrahim; Azali Muhammad; Ab. Razak Hamzah; Abd. Aziz Mohamed; Mohamad Pauzi Ismail

2008-01-01

The processing was made not only to show what are in the film but also to produce radiograph with high quality where the information gathered really presented level of the quality of the object inspected. Besides that, good procedure will make the film with good quality can keep the film in long time for reference. Here, more detailed on how the dark room functioned and its design. So, the good procedure while processed the film will be discussed detailed in this chapter from entering the dark room to exit from there.
MCWASP XIV: International Conference on Modelling of Casting, Welding and Advanced Solidification Processes

International Nuclear Information System (INIS)

Yasuda, H

2015-01-01

The current volume represents contributed papers of the proceedings of the 14th international conference on ''Modeling of Casting, Welding and Advanced Solidification Processes (MCWASP XIV)'', Yumebutai International Conference Center, Awaji island, Hyogo, Japan on 21 – 26 June, 2016. The first conference of the series 'Modeling of Casting, Welding and Advanced Solidification Processes (MCWASP)' was started up in 1980, and this is the 14th conference. The participants are more than 100 scientists from industry and academia, coming from 19 countries. In the conference, we have 5 invited, 70 oral and 31 poster presentations on different aspects of the modeling. The conference deals with various casting processes (Ingot / shape casting, continuous casting, direct chill casting and welding), fundamental phenomena (nucleation and growth, dendritic growth, eutectic growth, micro-, meso- and macrostructure formation and defect formation), coupling problems (electromagnetic interactions, application of ultrasonic wave), development of experimental / computational methods and so on. This volume presents the cutting-edge research in the modeling of casting, welding and solidification processes. I would like to thank MAGMA Giessereitechnologie GmbH, Germany and SCSK Corporation, Japan for supporting the publication of contributed papers. Hideyuki Yasuda Conference Chairman Department of Materials Science and Engineering, Kyoto University Japan (preface)
Simulation of mould filling process for composite skeleton castings

Directory of Open Access Journals (Sweden)

M. Dziuba

2008-04-01

Full Text Available In this work authors showed selected results of simulation and experimental studies on temperature distribution during solidification of skeleton casting and mould filling process. The aim of conducted simulations was the choice of thermal and geometrical parameters for the needs of designed calculations of the skeleton castings and the estimation of the guidelines for the technology of manufacturing. The subject of numerical simulation was the analysis of ability of filling the channels of core by liquid metal at estability technological parameters.. Below the assumptions and results of the initial simulated calculations are presented. The total number of the nodes in the casting was 1920 and of the connectors was 5280 what gave filling of 100% for the nodes and 99,56% for the connectors in the results of the simulation. Together it resulted as 99,78 % of filling the volume of the casting. The nodes and connectors were filled up to the 30 level of the casting in the simulation. The all connectors were filled up to the 25 level of the casting in the simulation. Starting from the 25 level individual connectors at the side surface of the casting weren’t filled up. The connectors weren’t supplied by multi-level getting system. The differences of filling the levels are little (maximally 5 per cent.
Friction Stir Processing of Cast Superalloys, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — This SBIR effort examines the feasibility of an innovative fabrication technology incorporating sand casting and friction stir processing (FSP) for producing...
PLC and SCADA based automation of injection casting process for casting of uranium-zirconium blanket fuel slugs for metallic fuel fabrication

International Nuclear Information System (INIS)

Yathish Kumar, G.; Jagadeeschandran, J.; Avvaru, Prafulla Kumar; Yadaw, Abhishek Kumar; Lavakumar, R.; Prabhu, T.V.; Muralidharan, P.; Anthonysamy, S.

2016-01-01

Fabrication of metallic (U-6wt.%Zr) slugs involves melting of binary alloy under vacuum and injection casting into quartz moulds at high pressure. Injection casting system housed inside glove box comprises of high vacuum, induction melting, high pressure control, motion control, mould preheating, chamber cooling, crucible handling and glove box pressure control systems. The technology development for process automation of injection casting system and process optimisation for fabrication of metallic (U-6%Zr) slugs is outlined in this paper. (author)
Numerical simulation of complex multi-phase fluid of casting process and its applications

Directory of Open Access Journals (Sweden)

CHEN Li-liang

2006-05-01

Full Text Available The fluid of casting process is a typical kind of multi-phase flow. Actually, many casting phenomena have close relationship with the multi-phase flow, such as molten metal filling process, air entrapment, slag movement, venting process of die casting, gas escaping of lost foam casting and so on. Obviously, in order to analyze these phenomena accurately, numerical simulation of the multi-phase fluid is necessary. Unfortunately, so far, most of the commercial casting simulation systems do not have the ability of multi-phase flow modeling due to the difficulty in the multi-phase flow calculation. In the paper, Finite Different Method (FDM technique was adopt to solve the multi-phase fluid model. And a simple object of the muiti-phase fluid was analyzed to obtain the fluid rates of the liquid phase and the entrapped air phase.
Mathematical Modelling of the Thermical Regime in the Continous Casting Process

Directory of Open Access Journals (Sweden)

Monika Erika POPA

2005-10-01

Full Text Available Continuous casting is one of the prominent methods of production of casts. Effective design and operation of continuous casting machines needs complete analysis of the continuous casting process. In this paper the basic principles of continuous casting and its heat transfer analysis using the finite element method are presented. In the analysis phase change is assumed to take place at constant temperature. A front tracking algorithm has been developed to predict the position of the solidification front at each step. Finally, examples that are solved by the proposed algorithm are discussed. The results show that there is a good agreement between the method developed in this work and other previously reported works.
Friction Stir Processing of Cast Superalloys, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — This SBIR Phase I effort examines the feasibility of an innovative fabrication technology incorporating sand casting and friction stir processing (FSP) for producing...
Manufacture and characterization of mucoadhesive buccal films.

Science.gov (United States)

Morales, Javier O; McConville, Jason T

2011-02-01

The buccal route of administration has a number of advantages including bypassing the gastrointestinal tract and the hepatic first pass effect. Mucoadhesive films are retentive dosage forms and release drug directly into a biological substrate. Furthermore, films have improved patient compliance due to their small size and reduced thickness, compared for example to lozenges and tablets. The development of mucoadhesive buccal films has increased dramatically over the past decade because it is a promising delivery alternative to various therapeutic classes including peptides, vaccines, and nanoparticles. The "film casting process" involves casting of aqueous solutions and/or organic solvents to yield films suitable for this administration route. Over the last decade, hot-melt extrusion has been explored as an alternative manufacturing process and has yielded promising results. Characterization of critical properties such as the mucoadhesive strength, drug content uniformity, and permeation rate represent the major research areas in the design of buccal films. This review will consider the literature that describes the manufacture and characterization of mucoadhesive buccal films. Copyright © 2010 Elsevier B.V. All rights reserved.
Predictive modeling of nanoscale domain morphology in solution-processed organic thin films

Science.gov (United States)

Schaaf, Cyrus; Jenkins, Michael; Morehouse, Robell; Stanfield, Dane; McDowall, Stephen; Johnson, Brad L.; Patrick, David L.

2017-09-01

The electronic and optoelectronic properties of molecular semiconductor thin films are directly linked to their extrinsic nanoscale structural characteristics such as domain size and spatial distributions. In films prepared by common solution-phase deposition techniques such as spin casting and solvent-based printing, morphology is governed by a complex interrelated set of thermodynamic and kinetic factors that classical models fail to adequately capture, leaving them unable to provide much insight, let alone predictive design guidance for tailoring films with specific nanostructural characteristics. Here we introduce a comprehensive treatment of solution-based film formation enabling quantitative prediction of domain formation rates, coverage, and spacing statistics based on a small number of experimentally measureable parameters. The model combines a mean-field rate equation treatment of monomer aggregation kinetics with classical nucleation theory and a supersaturation-dependent critical nucleus size to solve for the quasi-two-dimensional temporally and spatially varying monomer concentration, nucleation rate, and other properties. Excellent agreement is observed with measured nucleation densities and interdomain radial distribution functions in polycrystalline tetracene films. Numerical solutions lead to a set of general design rules enabling predictive morphological control in solution-processed molecular crystalline films.
Solid-state densification of spun-cast self-assembled monolayers for use in ultra-thin hybrid dielectrics

Energy Technology Data Exchange (ETDEWEB)

Hutchins, Daniel O.; Acton, Orb [Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195 (United States); Weidner, Tobias [Department of Bioengineering, University of Washington, Seattle, WA 98195 (United States); Cernetic, Nathan [Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195 (United States); Baio, Joe E. [Department of Chemical Engineering, University of Washington, Seattle, WA 98195 (United States); Castner, David G. [Department of Bioengineering, University of Washington, Seattle, WA 98195 (United States); Department of Chemical Engineering, University of Washington, Seattle, WA 98195 (United States); Ma, Hong, E-mail: hma@uw.edu [Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195 (United States); Jen, Alex K.-Y., E-mail: ajen@uw.edu [Department of Materials Science and Engineering, University of Washington, Seattle, WA 98195 (United States); Department of Chemistry, University of Washington, Seattle, WA 98195 (United States)

2012-11-15

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

OpenAIRE

M. Dziuba; M. Cholewa

2008-01-01

In this work authors showed selected results of simulation and experimental studies on temperature distribution during solidification of skeleton casting and mould filling process. The aim of conducted simulations was the choice of thermal and geometrical parameters for the needs of designed calculations of the skeleton castings and the estimation of the guidelines for the technology of manufacturing. The subject of numerical simulation was the analysis of ability of filling the channels of c...
Structure-property-processing correlations in freeze-cast composite scaffolds.

Science.gov (United States)

Hunger, Philipp M; Donius, Amalie E; Wegst, Ulrike G K

2013-05-01

Surprisingly few reports have been published, to date, on the structure-property-processing correlations observed in freeze-cast materials directionally solidified from polymer solutions, or ceramic or metal slurries. The studies that exist focus on properties of sintered ceramics, that is materials whose structure was altered by further processing. In this contribution, we report first results on correlations observed in alumina-chitosan-gelatin composites, which were chosen as a model system to test and compare the effect of particle size and processing parameters on their mechanical properties at a specific composition. Our study reveals that highly porous (>90%) hybrid materials can be manufactured by freeze casting, through the self-assembly of a polymer and a ceramic phase that occurs during directional solidification, without the need of additional processing steps such as sintering or infiltration. It further illustrates that the properties of freeze-cast hybrid materials can independently be tailored at two levels of their structural hierarchy, allowing for the simultaneous optimization of both mechanical and structural requirements. An increase in freezing rate resulted in decreases in lamellar spacing, cell wall thickness, pore aspect ratio and cross-sectional area, as well as increases in both Young's modulus and compressive yield strength. The mechanical properties of the composite scaffolds increased with an increasing particle size. The results show that both structure and mechanical properties of the freeze-cast composites can be custom-designed and that they are thus ideally suited for a large variety of applications that require high porosity at low or medium load-bearing capacity. Copyright © 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
Thin film processes II

CERN Document Server

Kern, Werner

1991-01-01

This sequel to the 1978 classic, Thin Film Processes, gives a clear, practical exposition of important thin film deposition and etching processes that have not yet been adequately reviewed. It discusses selected processes in tutorial overviews with implementation guide lines and an introduction to the literature. Though edited to stand alone, when taken together, Thin Film Processes II and its predecessor present a thorough grounding in modern thin film techniques.Key Features* Provides an all-new sequel to the 1978 classic, Thin Film Processes* Introduces new topics, and sever
Preparation and characterizations of polyaniline (PANI)/ZnO nanocomposites film using solution casting method

International Nuclear Information System (INIS)

Ahmed, Faheem; Kumar, Shalendra; Arshi, Nishat; Anwar, M.S.; Su-Yeon, Lee; Kil, Gyung-Suk; Park, Dae-Won; Koo, Bon Heun; Lee, Chan Gyu

2011-01-01

Polyaniline (PANI)-ZnO nanoparticles composites film has been successfully fabricated by solution casting technique on glass substrate in which ZnO nanopowder was prepared via auto combustion method and used as inorganic materials. The as-grown nanocomposites film has been characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, Transmission electron microscopy (TEM) and Atomic Force Microscopy (AFM) for their structural and morphological characterizations. X-ray diffraction studies of as-grown film showed the reflection of ZnO nanoparticles along with a broad peak of PANI. The AFM study of the film shows the incorporation of ZnO nanoparticles into the polymer matrix which was further supported by roughness measurement. TEM images showed that the size of ZnO nanoparticles in the nanocomposites increase from ∼ 35 nm to ∼ 45 nm, indicating the interaction of nanoparticles with PANI molecular chains. FTIR spectra showed a band at 501 cm -1 due to ZnO nanoparticles while the hydrogen bonding between the amine group of PANI and ZnO nanoparticles had been confirmed from the presence of the absorption band at 1148 cm -1 .
Crystallization behavior of polyethylene on silicon wafers in solution casting processes traced by time-resolved measurements of synchrotron grazing-incidence small-angle and wide-angle X-ray scattering

International Nuclear Information System (INIS)

Sasaki, S; Masunaga, H; Takata, M; Itou, K; Tashiro, K; Okuda, H; Takahara, A

2009-01-01

Crystallization behavior of polyethylene (PE) on silicon wafers in solution casting processes has been successfully traced by time-resolved grazing-incidence small-angle and wide-angle X-ray scattering (GISWAXS) measurements utilizing synchrotron radiation. A p-xylene solution of PE kept at ca. 343 K was dropped on a silicon wafer at ca. 298 K. While the p-xylene evaporated naturally from the dropped solution sample, PE chains crystallized to be a thin film. Raman spectral measurements were performed simultaneously with the GISWAXS measurements to evaluate quantitatively the p-xylene the dropped solution contained. Grazing-incidence wide-angle X-ray scattering (GIWAXS) patterns indicated nucleation and crystal growth in the dropped solution and the following as-cast film. GIWAXS and Raman spectral data revealed that crystallization of PE was enhanced after complete evaporation of the p-xylene from the dropped solution. The [110] and [200] directions of the orthorhombic PE crystal became relatively parallel to the wafer surface with time, which implied that the flat-on lamellae with respect to the wafer surface were mainly formed in the as-cast film. On the other hand, grazing-incidence small-angle X-ray scattering (GISAXS) patterns implied formation of isolated lamellae in the dropped solution. The lamellae and amorphous might alternatively be stacked in the preferred direction perpendicular to the wafer surface. The synchrotron GISWAXS experimental method could be applied for kinetic study on hierarchical structure of polymer thin films.
Polyether ether ketone film. Polyether ether ketone film

Energy Technology Data Exchange (ETDEWEB)

Suzuki, S. (Sumitomo Chemical Co. Ltd., Tokyo (Japan))

1990-07-05

The characteristics and the film making process of polyether ether ketone (PEEK) resin, and the characteristics and the applications of PEEK film, are described. PEEK is aromatic polyketone with super thermal resistance. Though it is a crystalline polymer of which the crystallinity is controlled to 48% in a highest degree, it has also amorphous property, thus it shows unique property. The characteristics of PEEK resin are found in thermal resistance, incombusti-bility, transparency, chemical resistance, light resistance and radiation resistance. As for the film making process, casting method by T-die is generally adopted. The general properties of PEEK film are excellent in high thermal resistance, good electrical properties, chemical resistance, hydrolysis resistance, radiation resistance and imcombusti-bility. In the application of PEEK film, new development is expected in following fields; a high performance composite, flexible print substrate with high thermal resistance, insulating tape with thermal resistance, and a general film in the nuclear energy industry. 5 figs., 5 tabs.

Analysis of the biomineralization process on SWNT-COOH and F-SWNT films

Energy Technology Data Exchange (ETDEWEB)

Armentano, Ilaria [Materials Engineering Centre, UdR INSTM, NIPLAB, University of Perugia, Terni (Italy)], E-mail: Ilaria.armentano@lnl.infn.it; Alvarez-Perez, Marco Antonio; Carmona-Rodriguez, Bruno [Laboratorio de Biologia Celular y Molecular, Facultad de Odontologia, Universidad Nacional Autonoma de Mexico, Mexico D. F. (Mexico); Gutierrez-Ospina, Ivan [Universidad Autonoma Metropolitana, Xochimilco, Mexico D. F. (Mexico); Kenny, Jose Maria [Materials Engineering Centre, UdR INSTM, NIPLAB, University of Perugia, Terni (Italy); Arzate, Higinio [Laboratorio de Biologia Celular y Molecular, Facultad de Odontologia, Universidad Nacional Autonoma de Mexico, Mexico D. F. (Mexico)

2008-12-01

In vitro biomineralization process was investigated on functionalized single wall nanotube (SWNT) films. The films were prepared by solvent casting method by using carboxylated and fluorinated nanotubes. SWNT films were characterized by means of electron microscopy, contact angle measurements and optical absorption. The in vitro assays were performed on cultured human alveolar bone-derived cells (HABDC) to determine the capabilities of carboxylated single-walled nanotubes (SWNTs-COOH) and fluorinated single-walled nanotubes (F-SWNTs) to promote the deposit of mineral-like tissue. The results showed that the cellular response of HABDC in secreting a mineralized extracellular matrix and their consequent mineralization is dependent on the degree of functionalization of the SWNTs. Differences were found related to the kind of sidewall functionalization. Both structures promoted hydroxyapatite formation, however, calcium uptake on SWNTs-COOH increased and it was related to crystal density. From our results, it is possible to infer that CNT functionalization opens a path to future developments in new bone graft materials and techniques.
Analysis of the biomineralization process on SWNT-COOH and F-SWNT films

International Nuclear Information System (INIS)

Armentano, Ilaria; Alvarez-Perez, Marco Antonio; Carmona-Rodriguez, Bruno; Gutierrez-Ospina, Ivan; Kenny, Jose Maria; Arzate, Higinio

2008-01-01

In vitro biomineralization process was investigated on functionalized single wall nanotube (SWNT) films. The films were prepared by solvent casting method by using carboxylated and fluorinated nanotubes. SWNT films were characterized by means of electron microscopy, contact angle measurements and optical absorption. The in vitro assays were performed on cultured human alveolar bone-derived cells (HABDC) to determine the capabilities of carboxylated single-walled nanotubes (SWNTs-COOH) and fluorinated single-walled nanotubes (F-SWNTs) to promote the deposit of mineral-like tissue. The results showed that the cellular response of HABDC in secreting a mineralized extracellular matrix and their consequent mineralization is dependent on the degree of functionalization of the SWNTs. Differences were found related to the kind of sidewall functionalization. Both structures promoted hydroxyapatite formation, however, calcium uptake on SWNTs-COOH increased and it was related to crystal density. From our results, it is possible to infer that CNT functionalization opens a path to future developments in new bone graft materials and techniques
Neutron radiography inspection of investment castings

International Nuclear Information System (INIS)

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

2004-01-01

Investment casting, also known as the lost wax process, is a manufacturing method employed to produce near net shape metal articles. Traditionally, investment casting has been used to produce structural titanium castings for aero-engine applications with wall thickness less than 1 in (2.54 cm). Recently, airframe manufacturers have been exploring the use of titanium investment casting to replace components traditionally produced from forgings. Use of titanium investment castings for these applications reduces weight, cost, lead time, and part count. Recently, the investment casting process has been selected to produce fracture critical structural titanium airframe components. These airframe components have pushed the traditional inspection techniques to their physical limits due to cross sections on the order of 3 in (7.6 cm). To overcome these inspection limitations, a process incorporating neutron radiography (n-ray) has been developed. In this process, the facecoat of the investment casting mold material contains a cocalcined mixture of yttrium oxide and gadolinium oxide. The presence of the gadolinium oxide, allows for neutron radiographic imaging (and eventual removal and repair) of mold facecoat inclusions that remain within these thick cross sectional castings. Probability of detection (POD) studies have shown a 3x improvement of detecting a 0.050x0.007 in 2 (1.270x0.178 mm 2 ) inclusion of this cocalcined material using n-ray techniques when compared to the POD using traditional X-ray techniques. Further, it has been shown that this n-ray compatible mold facecoat material produces titanium castings of equal metallurgical quality when compared to the traditional materials. Since investment castings can be very large and heavy, the neutron radiography facilities at the University of California, Davis McClellan Nuclear Radiation Center (UCD/MNRC) were used to develop the inspection techniques. The UCD/MNRC has very unique facilities that can handle large parts
The influence of the parameters of lost foam process on the quality of aluminum alloys castings

Directory of Open Access Journals (Sweden)

Aćimović-Pavlović Zagorka

2010-01-01

Full Text Available This paper presents the research results of application of Lost foam process for aluminum alloys castings of a simple geometry. The process characteristic is that patterns and gating of moulds, made of polymers, stay in the mould till the liquid metal inflow. In contact with the liquid metal, pattern intensely and in relatively short time decomposes and evaporates, which is accompanied by casting crystallization. As a consequence of polymer pattern decomposition and evaporation a great quantity of liquid and gaseous products are produced, which is often the cause of different types of casting errors. This paper presents the results of a research with a special consideration given to detecting and analyzing the errors of castings. In most cases the cause of these errors are defects of polymer materials used for evaporable patterns production, as well as defects of materials for refractory coatings production for polymer patterns. The researches have shown that different types of coatings determine properties of the obtained castings. Also, the critical processing parameters (polymer pattern density, casting temperature, permeability of refractory coating and sand, construction of patterns and gating of moulds significantly affect on castings quality. During the research a special consideration was given to control and optimization of these parameters with the goal of achieving applicable castings properties. The study of surface and internal error of castings was performed systematically in order to carry out preventive measures to avoid errors and minimize production costs. In order to achieve qualitative and profitable castings production by the method of Lost foam it is necessary to reach the balance in the system: evaporable polymer pattern - liquid metal - refractory coating - sandy cast in the phase of metal inflow, decomposition and evaporation of polymer pattern, formation and solidification of castings. By optimizing the processing
Improvement of food packaging related properties in whey protein isolate‑based nanocomposite films and coatings by addition of montmorillonite nanoplatelets

Science.gov (United States)

Schmid, Markus; Merzbacher, Sarah; Brzoska, Nicola; Müller, Kerstin; Jesdinszki, Marius

2017-11-01

In the present study the effects of the addition of montmorillonite (MMT) nanoplatelets on whey protein isolate (WPI)-based nanocomposite films and coatings were investigated. The main objective was the development of WPI-based MMT-nanocomposites with enhanced barrier and mechanical properties. WPI-based nanocomposite cast-films and coatings were prepared by dispersing 0 % (reference sample), 3 %, 6 %, 9 % (w/w protein) MMT, or, depending on the protein concentration, also 12 % and 15 % (w/w protein) MMT into native WPI-based dispersions, followed by subsequent denaturation during the drying and curing process. The natural MMT nanofillers could be randomly dispersed into film-forming WPI-based nanodispersions, displaying good compatibility with the hydrophilic biopolymer matrix. As a result, by addition of 15 % (w/w protein) MMT into 10 % (w/w dispersion) WPI-based cast-films or coatings, the oxygen permeability (OP) was reduced by 91 % for glycerol-plasticized and 84 % for sorbitol-plasticized coatings, water vapor transmission rate (WVTR) was reduced by 58 % for sorbitol-plasticized cast-films. Due to the addition of MMT- nanofillers the Young’s modulus and tensile strength improved by 315 % and 129 %, respectively, whereas elongation at break declined by 77 % for glycerol-plasticized cast-films. In addition, comparison of plasticizer type revealed that sorbitol-plasticized cast-films were generally stiffer and stronger, but less flexible compared glycerol-plasticized cast-films. Viscosity measurements demonstrated good processability and suitability for up-scaled industrial processes of native WPI-based nanocomposite dispersions, even at high nanofiller-loadings. These results suggest that the addition of natural MMT- nanofillers into native WPI-based matrices to form nanocomposite films and coatings holds great potential to replace well-established, fossil-based packaging materials for at least certain applications such as oxygen barriers as part of
Physicochemical and Microstructural Characterization of Corn Starch Edible Films Obtained by a Combination of Extrusion Technology and Casting Technique.

Science.gov (United States)

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

2016-09-01

Starch edible films (EFs) have been widely studied due to their potential in food preservation; however, their application is limited because of their poor mechanical and barrier properties. Because of that, the aim of this work was to use the extrusion technology (Ex T) as a pretreatment of casting technique to change the starch structure in order to obtain EFs with improved physicochemical properties. To this, corn starch and a mixture of plasticizers (sorbitol and glycerol, in different ratios) were processed in a twin screw extruder to generate the starch modification and subsequently casting technique was used for EFs formation. The best conditions of the Ex T and plasticizers concentration were obtained using response surface methodology. All the response variables evaluated, were affected significatively by the Plasticizers Ratio (Sorbitol:Glycerol) (PR (S:G)) and Extrusion Temperature (ET), while the Screw Speed (SS) did not show significant effect on any of these variables. The optimization study showed that the appropriate conditions to obtain EFs with the best mechanical and barrier properties were ET = 89 °C, SS = 66 rpm and PR (S:G) = 79.7:20.3. Once the best conditions were obtained, the optimal treatment was characterized according to its microstructural properties (X-ray diffraction, Scanning Electron Microscopy and Atomic Force Microscopy) to determine the damage caused in the starch during Ex T and casting technique. In conclusion, with the combination of Ex T and casting technique were obtained EFs with greater breaking strength and deformation, as well as lower water vapor permeability than those reported in the literature. © 2016 Institute of Food Technologists®
Solidification, processing and properties of ductile cast iron

DEFF Research Database (Denmark)

Tiedje, Niels Skat

2010-01-01

Ductile cast iron has been an important engineering material in the past 50 years. In that time, it has evolved from a complicated material that required the foundry metallurgist's highest skill and strict process control to being a commonly used material that can easily be produced with modern...... of the latest years of research indicate that ductile cast iron in the future will become a highly engineered material in which strict control of a range of alloy elements combined with intelligent design and highly advanced processing allows us to target properties to specific applications to a much higher...... degree than we have seen previously. It is the aim of the present paper to present ductile iron as a modern engineering material and present the many different possibilities that the material hides. Focus will be on the latest research in solidification and melt treatment. But for completeness...
Die design and process optimization of die cast V6 engine blocks

Directory of Open Access Journals (Sweden)

Henry Hu

2005-02-01

Full Text Available The use of aluminum, particularly for engine blocks, has grown considerably in the past ten years, and continues to rise in the automotive industry. In order to enhance the quality and engineering functionality of die cast engine blocks, die design and processes have to be optimized. In this study, a computer simulation software, MAGMAsoft, as an advanced tool for optimizing die design and casting process, was emplooyed to virtually visualize cavity filling and patterns of a V6 engine block. The original die design and process was simulated first to establish a baseline. A reality check was used to verify the predicted results. Then, the die modification with a different unner system was made by using a CAD software, Unigraphics (UG. The simulation on combinations of the modified die design and revised process was performed to examine the effect of die modification and process change on flow filling of V6 engine blocks. The simulated prediction indicateds that the enhancement of cavity filling due to the die and process modification minimizeds the occurrence of defects during casting, and consequently improves the quality of blocks. The results of mechanical testing show a significant increase in fatigue strengths, and a moderately improvement on tensile properties for the blocks die cast with the new die design and prpocess in comparison with those produced by the original ones.
Galvanic corrosion of copper-cast iron couples

International Nuclear Information System (INIS)

Smart, N.R.; Rance, A.P.; Fennell, P.A.H.

2005-01-01

the corrosion rates were near 100 μm/year for the cast iron at 50 deg C in the presence of oxygen. There was evidence of temporary polarity reversal at very low levels of current (i.e. the copper became the anode). The galvanic corrosion rates of iron coupled to copper at low groundwater oxygen concentrations were close to the values measured for anaerobic corrosion rates of uncoupled iron. Under deaerated conditions a black film was formed on the surface of the cast iron, which was consistent with the formation of magnetite. The electrochemical potentials of the cast iron-copper couples in deaerated conditions were in the thermodynamically stable regions for magnetite and metallic copper. The galvanic currents under deaerated conditions were higher at 50 deg C than at 30 deg C, by a factor of up to 10. This can be attributed to an increase in the exchange current density for the water reduction reaction on the copper cathode and to an increase in the rate of diffusion processes in the oxide film on cast iron. There was some evidence for an increase in the galvanic corrosion rate in the presence of bentonite slurry compared to fully aqueous artificial groundwaters. Pre-grown corrosion films on cast iron did not have a significant effect on subsequent measured galvanic corrosion rates when coupled to copper in deaerated conditions. None of the MCA specimens exhibited any signs of galvanically enhanced crevice corrosion under deaerated conditions. In terms of application of the results to the evolution of the environment within the annulus of the canister the following scenario is envisaged. If water penetrates the annulus through a hole in the outer copper container a galvanic couple will be set up between the copper and the cast iron insert. The current passing between the copper and the cast iron will be concentrated at the contact points. If any residual air is present in the annulus the corrosion rate of the cast iron will be enhanced (i.e. the iron will be the
Quality and Safety Assurance of Iron Casts and Manufacturing Processes

Directory of Open Access Journals (Sweden)

Kukla S.

2016-06-01

Full Text Available The scope of this work focuses on the aspects of quality and safety assurance of the iron cast manufacturing processes. Special attention was given to the processes of quality control and after-machining of iron casts manufactured on automatic foundry lines. Due to low level of automation and huge work intensity at this stage of the process, a model area was established which underwent reorganization in accordance with the assumptions of the World Class Manufacturing (WCM. An analysis of work intensity was carried out and the costs were divided in order to identify operations with no value added, particularly at individual manufacturing departments. Also an analysis of ergonomics at work stations was carried out to eliminate activities that are uncomfortable and dangerous to the workers' health. Several solutions were proposed in terms of rationalization of work organization at iron cast after-machining work stations. The proposed solutions were assessed with the use of multi-criteria assessment tools and then the best variant was selected based on the assumed optimization criteria. The summary of the obtained results reflects benefits from implementation of the proposed solutions.
Development of melting and casting process for Nb-Al intermetallic compounds and mechanical properties

International Nuclear Information System (INIS)

Kamata, Kinya; Degawa, Toru; Nagashima, Yoshinori

1993-01-01

The shaping methods of Nb-Al intermetallic compounds, especially melting and casting, have considerably different characteristics as compared with those for other metals and alloys. The authors have investigated melting and casting processes for Nb-Al compounds to develop precision casting processes for these intermetallics. Fundamental properties of Nb-Al compound castings have been also investigated for high temperature structural use in this work. An advanced Induction Skull Melting (ISM) furnace has been developed and the advantages of ISM have been recognized as a result of this study. The mechanical properties, such as hardness and compression strength, are dependent upon the Al content in Nb-Al binary compounds
Numerical modelling of evaporation in a ceramic layer in the tape casting process

DEFF Research Database (Denmark)

Jabbaribehnam, Mirmasoud; Jambhekar, V. A.; Hattel, Jesper Henri

2016-01-01

Evaporation of water from a ceramic layer is a key phenomenon in the drying process for the manufacturing of tape cast ceramics. This process contains mass, momentum and energy exchange between the porous medium and the free-flow region. In order to analyze such interaction processes, a Represent......Evaporation of water from a ceramic layer is a key phenomenon in the drying process for the manufacturing of tape cast ceramics. This process contains mass, momentum and energy exchange between the porous medium and the free-flow region. In order to analyze such interaction processes...
Mechanism and application of a newly developed pressure casting process: horizontal squeeze casting

Directory of Open Access Journals (Sweden)

Li Peijie

2014-07-01

Full Text Available Compared to traditional high-pressure die casting (HPDC, horizontal squeeze casting (HSC is a more promising way to fabricate high-integrity castings, owing to a reduced number of gas and shrinkage porosities produced in the casting. In this paper, the differences between HSC and HPDC are assessed, through which it is shown that the cavity filling velocity and the size of the gating system to be the most notable differences. Equipment development and related applications are also reviewed. Furthermore, numerical simulation is used to analyze the three fundamental characteristics of HSC: slow cavity filling, squeeze feeding and slow sleeve filling. From this, a selection principle is given based on the three related critical casting parameters: cavity filling velocity, gate size and sleeve filling velocity. Finally, two specific applications of HSC are introduced, and the future direction of HSC development is discussed.
Toxicological evaluation of natural rubber films from vulcanized latex by the conventional process and the alternative process with ionizing radiation; Avaliacao toxicologica de filmes de borracha natural obtidos do latex vulcanizado pelo processo convencional e pelo processo alternativo com radiacao ionizante

Energy Technology Data Exchange (ETDEWEB)

Campos, Vania Elisabeth

1997-07-01

The industrial vulcanization of natural rubber latex (NRL) is made all over the world by conventional process using sulphur and heat but it can be made by an alternative process using ionizing radiation. In this research the NRL was tested by 13 physical, chemical and mechanical assays which showed its good quality. It was done a preliminary study of the toxicological properties of 4 natural rubber films obtained by casting process of NRL: one non vulcanized, other vulcanized by the conventional process and two vulcanized by the alternative process. In the alternative process the films were obtained by irradiation of NRL by gamma rays from the {sup 60} Co source at 250 kGy in the absence of sensitizer and irradiated NRL at 12 kGy in the presence of 4ph r of n-butyl acrylate / 0.2 phr of KOH. These vulcanization doses were determined from broken tensile strength. In the conventional process, sulphur vulcanized NRL was made using a classical composition. Another film was made with non vulcanized NRL. The preliminary evaluation of the toxicological properties was made from in vitro cytotoxicity and in vivo systemic toxicity assays. The LBN films vulcanized by the alternative process have less cytotoxicity than the NRL film vulcanized by the conventional process. The sensitized vulcanized films by gamma rays and non vulcanized films showed similar cytotoxicity while the vulcanized films without sensitizer showed a slight lower cytotoxicity. The non vulcanized NRL film and the NRL films vulcanized by the alternative process did not show toxic effects in the 72 hours period of the systemic toxicity assay. However the NRL film vulcanized with sulphur induced effects like allaying and motor in coordination on the animals treated with an oil extract at the fourth hour and recovering after that. The alternative process promoted lower toxic effects than conventional process because there was no toxic substances present. (author)
PHYSICOCHEMICAL AND ANTIBACTERIAL PROPERTIES OF PLA-CHITOSAN BLENDS OBTAINED BY CASTING WITH POTENTIAL USE AS AGRICULTURAL MULCH FILMS

Directory of Open Access Journals (Sweden)

Danila Merino

2016-03-01

Full Text Available PLA-Chitosan films compatibilized with hexamethylenediisocyanate (HDI were obtained by casting and subsequent hot pressing. The films were prepared with different contents of chitosan (CS and then its physicochemical properties were studied by Fourier Transform infrared spectroscopy (FTIR, thermogravimetric analysis (TGA, differential scanning calorimetry (DSC, optical microscopy (OM and X-ray diffraction (XRD. It was found that the compatibilizing agent reacts completely and that chitosan affects the thermal properties of the films decreasing their decomposition temperatures, glass transition temperature (Tg and melting (Tm and increase its crystallinity. From the functional standpoint, antimicrobial properties of each blend were tested against Pseudomonas syringae pv tomato DC-3000. The increase in chitosan content was proportional to the antimicrobial effect allowing project its potential application in the agronomic field.
Solid-State Densification of Spun-Cast Self-Assembled Monolayers for Use in Ultra-Thin Hybrid Dielectrics.

Science.gov (United States)

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

2012-11-15

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

International Nuclear Information System (INIS)

Kelly, Andrew; Hardcastle, Nicholas; Metcalfe, Peter; Cutajar, Dean; Quinn, Alexandra; Cardoso, Michael; Rosenfeld, Anatoly; Foo, Kerwyn; Barlin, Sheree

2011-01-01

Curative breast radiotherapy typically leaves patients with varying degrees of cosmetic damage. One problem interfering with cosmetically acceptable breast radiotherapy is the external contour for large pendulous breasts which often results in high doses to skin folds. Thermoplastic casts are often employed to secure the breasts to maintain setup reproducibility and limit the presence of skin folds. This paper aims to determine changes in surface dose that can be attributed to the use of thermoplastic immobilization casts. Skin dose for a clinical hybrid conformal/IMRT breast plan was measured using radiochromic film and MOSFET detectors at a range of water equivalent depths representative of the different skin layers. The radiochromic film was used as an integrating dosimeter, while the MOSFETs were used for real-time dosimetry to isolate the contribution of skin dose from individual IMRT segments. Strips of film were placed at various locations on the breast and the MOSFETs were used to measure skin dose at 16 positions spaced along the film strips for comparison of data. The results showed an increase in skin dose in the presence of the immobilization cast of up to 45.7% and 62.3% of the skin dose without the immobilization cast present as measured with Gafchromic EBT film and MOSFETs, respectively. The increase in skin dose due to the immobilization cast varied with the angle of beam incidence and was greatest when the beam was normally incident on the phantom. The increase in surface dose with the immobilization cast was greater under entrance dose conditions compared to exit dose conditions.
Surface dosimetry for breast radiotherapy in the presence of immobilization cast material

Science.gov (United States)

Kelly, Andrew; Hardcastle, Nicholas; Metcalfe, Peter; Cutajar, Dean; Quinn, Alexandra; Foo, Kerwyn; Cardoso, Michael; Barlin, Sheree; Rosenfeld, Anatoly

2011-02-01

Curative breast radiotherapy typically leaves patients with varying degrees of cosmetic damage. One problem interfering with cosmetically acceptable breast radiotherapy is the external contour for large pendulous breasts which often results in high doses to skin folds. Thermoplastic casts are often employed to secure the breasts to maintain setup reproducibility and limit the presence of skin folds. This paper aims to determine changes in surface dose that can be attributed to the use of thermoplastic immobilization casts. Skin dose for a clinical hybrid conformal/IMRT breast plan was measured using radiochromic film and MOSFET detectors at a range of water equivalent depths representative of the different skin layers. The radiochromic film was used as an integrating dosimeter, while the MOSFETs were used for real-time dosimetry to isolate the contribution of skin dose from individual IMRT segments. Strips of film were placed at various locations on the breast and the MOSFETs were used to measure skin dose at 16 positions spaced along the film strips for comparison of data. The results showed an increase in skin dose in the presence of the immobilization cast of up to 45.7% and 62.3% of the skin dose without the immobilization cast present as measured with Gafchromic EBT film and MOSFETs, respectively. The increase in skin dose due to the immobilization cast varied with the angle of beam incidence and was greatest when the beam was normally incident on the phantom. The increase in surface dose with the immobilization cast was greater under entrance dose conditions compared to exit dose conditions.
Effect of extrusion process on the functional properties of high amylose corn starch edible films and its application in mango (Mangifera indica L.) cv. Tommy Atkins.

Science.gov (United States)

Calderón-Castro, Abraham; Vega-García, Misael Odín; de Jesús Zazueta-Morales, José; Fitch-Vargas, Perla Rosa; Carrillo-López, Armando; Gutiérrez-Dorado, Roberto; Limón-Valenzuela, Víctor; Aguilar-Palazuelos, Ernesto

2018-03-01

Starch is an attractive raw material as ingredient for edible film manufacture because of its low cost, abundant availability, renewability, and biodegradability. Nevertheless, starch based films exhibit several disadvantages such as brittleness and poor mechanical and barrier properties, which restrict its application for food packaging. The use of the extrusion technology as a pretreatment of the casting technique to change the starch structure in order to obtain edible films, may constitute an alternative to generate coatings with good functional properties and maintain longer the postharvest quality and shelf life of fruits. For this reason, the objective of this study was to optimize the conditions of an extrusion process to obtain a formulation of modified starch to elaborate edible films with good functional properties using the casting technique and assess the effect during the storage when applied on a model fruit. The best conditions of the extrusion process and concentration of plasticizers were obtained using response surface methodology. From optimization study, it was found that appropriate conditions to obtain starch edible films with the best mechanical and barrier properties were an extrusion temperature of 100 °C and a screw speed of 120 rpm, while the glycerol content was 16.73%. Also, once applied in fruit, the loss of quality attributes was diminished.
Novel casting processes for single-crystal turbine blades of superalloys

Science.gov (United States)

Ma, Dexin

2018-03-01

This paper presents a brief review of the current casting techniques for single-crystal (SC) blades, as well as an analysis of the solidification process in complex turbine blades. A series of novel casting methods based on the Bridgman process were presented to illustrate the development in the production of SC blades from superalloys. The grain continuator and the heat conductor techniques were developed to remove geometry-related grain defects. In these techniques, the heat barrier that hinders lateral SC growth from the blade airfoil into the extremities of the platform is minimized. The parallel heating and cooling system was developed to achieve symmetric thermal conditions for SC solidification in blade clusters, thus considerably decreasing the negative shadow effect and its related defects in the current Bridgman process. The dipping and heaving technique, in which thinshell molds are utilized, was developed to enable the establishment of a high temperature gradient for SC growth and the freckle-free solidification of superalloy castings. Moreover, by applying the targeted cooling and heating technique, a novel concept for the three-dimensional and precise control of SC growth, a proper thermal arrangement may be dynamically established for the microscopic control of SC growth in the critical areas of large industrial gas turbine blades.

Adaptive neural network controller for the molten steel level control of strip casting processes

International Nuclear Information System (INIS)

Chen, Hung Yi; Huang, Shiuh Jer

2010-01-01

The twin-roll strip casting process is a steel-strip production method which combines continuous casting and hot rolling processes. The production line from molten liquid steel to the final steel-strip is shortened and the production cost is reduced significantly as compared to conventional continuous casting. The quality of strip casting process depends on many process parameters, such as molten steel level in the pool, solidification position, and roll gap. Their relationships are complex and the strip casting process has the properties of nonlinear uncertainty and time-varying characteristics. It is difficult to establish an accurate process model for designing a model-based controller to monitor the strip quality. In this paper, a model-free adaptive neural network controller is developed to overcome this problem. The proposed control strategy is based on a neural network structure combined with a sliding-mode control scheme. An adaptive rule is employed to on-line adjust the weights of radial basis functions by using the reaching condition of a specified sliding surface. This surface has the on-line learning ability to respond to the system's nonlinear and time-varying behaviors. Since this model-free controller has a simple control structure and small number of control parameters, it is easy to implement. Simulation results, based on a semi experimental system dynamic model and parameters, are executed to show the control performance of the proposed intelligent controller. In addition, the control performance is compared with that of a traditional Pid controller
Through-plane uniformity of optical anisotropy in spin-coated biphenyl dianhydride-p-phenylenediamine films

International Nuclear Information System (INIS)

Diao Jie; Hess, Dennis W.

2005-01-01

The uniformity of the average refractive index and birefringence of poly-(biphenyl dianhydride-p-phenylenediamine) (BPDA-PDA) films has been investigated experimentally as a function of film thickness. Spin-cast and cured BPDA-PDA films were thinned sequentially by reactive ion etching and the dependence of average refractive index and birefringence on the post-thinned film thickness was determined using a prism wave-guide coupler. Negligible changes in the average refractive index and the birefringence were observed as a result of the thinning process. These results confirm previous assumptions that assert uniform optical anisotropy in the through-plane direction for spin-cast BPDA-PDA films
Market Opportunity of Some Aluminium Silicon Alloys Materials through Changing the Casting Process

Directory of Open Access Journals (Sweden)

Delfim SOARES

2012-08-01

Full Text Available Fatigue is considered to be the most common mechanism by which engineering components fail, and it accounts for at least 90% of all service failures attributed to mechanical causes. Mechanical properties (tensile strength, tensile strain, Young modulus, etc as well as fatigue properties (fatigue life are very dependent on casting method. The most direct effects of casting techniques are on the metallurgical microstructure that bounds the mechanical properties. One of the important variables affected by the casting technique is the cooling rate which is well known to strongly restrict the microstructure. In the present research has been done a comparison of fatigue properties of two aluminum silicon alloys obtained by two casting techniques. It was observed that the fatigue life is increasing with 24% for Al12Si and 31% for AL18Si by using centrifugal casting process instead of gravity casting. This increasing in fatigue life means that a component tailored from materials obtained by centrifugal casting will stay longer in service. It was made an estimation of the time required to recover the costs of technology in order to use the centrifuge process that will allow to obtain materials with improved properties. The amortization can be achieved by using two different marketing techniques: through the release of the product at the old price and with much longer life of the component which means "same price - longer life", or increasing price, by highlighting new product performance which means "higher price - higher properties".
Optimization of casting defects analysis with supply chain in cast iron foundry process

Directory of Open Access Journals (Sweden)

C. Narayanaswamy

2016-10-01

Full Text Available Some of the foundries are in need of meeting production targets and due to the urgency they ignore the rejections. The objective of this paper is to analyze the various defects, [1] from molding process in a cast iron foundry. The Failure Mode Effects Analysis (FMEA in quality control [2-6] with suitable supply chain for mold making process considering rejection rates are identified and analyzed in terms of Risk Priority Number (RPN to prioritize the attention for each of the problem. The optimum levels of selected parameters [7] are obtained in this analysis.
Structure/Processing Relationships of Highly Ordered Lead Salt Nanocrystal Superlattices

KAUST Repository

Hanrath, Tobias; Choi, Joshua J.; Smilgies, Detlef-M.

2009-01-01

We investigated the influence of processing conditions, nanocrystal/substrate interactions and solvent evaporation rate on the ordering of strongly interacting nanocrystals by synergistically combining electron microscopy and synchrotron-based small-angle X-ray scattering analysis. Spin-cast PbSe nanocrystal films exhibited submicrometer-sized supracrystals with face-centered cubic symmetry and (001)s planes aligned parallel to the substrate. The ordering of drop-cast lead salt nanocrystal films was sensitive to the nature of the substrate and solvent evaporation dynamics. Nanocrystal films drop-cast on rough indium tin oxide substrates were polycrystalline with small grain size and low degree of orientation with respect to the substrate, whereas films drop-cast on flat Si substrates formed highly ordered face-centered cubic supracrystals with close-packed (111)s planes parallel to the substrate. The spatial coherence of nanocrystal films drop-cast in the presence of saturated solvent vapor was significantly improved compared to films drop-cast in a dry environment. Solvent vapor annealing was demonstrated as a postdeposition technique to modify the ordering of nanocrystals in the thin film. Octane vapor significantly improved the long-range order and degree of orientation of initially disordered or polycrystalline nanocrystal assemblies. Exposure to 1,2-ethanedithiol vapor caused partial displacement of surface bound oleic acid ligands and drastically degraded the degree of order in the nanocrystal assembly. © 2009 American Chemical Society.
Structure/Processing Relationships of Highly Ordered Lead Salt Nanocrystal Superlattices

KAUST Repository

Hanrath, Tobias

2009-10-27

We investigated the influence of processing conditions, nanocrystal/substrate interactions and solvent evaporation rate on the ordering of strongly interacting nanocrystals by synergistically combining electron microscopy and synchrotron-based small-angle X-ray scattering analysis. Spin-cast PbSe nanocrystal films exhibited submicrometer-sized supracrystals with face-centered cubic symmetry and (001)s planes aligned parallel to the substrate. The ordering of drop-cast lead salt nanocrystal films was sensitive to the nature of the substrate and solvent evaporation dynamics. Nanocrystal films drop-cast on rough indium tin oxide substrates were polycrystalline with small grain size and low degree of orientation with respect to the substrate, whereas films drop-cast on flat Si substrates formed highly ordered face-centered cubic supracrystals with close-packed (111)s planes parallel to the substrate. The spatial coherence of nanocrystal films drop-cast in the presence of saturated solvent vapor was significantly improved compared to films drop-cast in a dry environment. Solvent vapor annealing was demonstrated as a postdeposition technique to modify the ordering of nanocrystals in the thin film. Octane vapor significantly improved the long-range order and degree of orientation of initially disordered or polycrystalline nanocrystal assemblies. Exposure to 1,2-ethanedithiol vapor caused partial displacement of surface bound oleic acid ligands and drastically degraded the degree of order in the nanocrystal assembly. © 2009 American Chemical Society.
Cellulose triacetate, thin film dielectric capacitor

Science.gov (United States)

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

1995-01-01

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

International Nuclear Information System (INIS)

Chen, C.H.; Altstetter, C.J.; Rigsbee, J.M.

1984-01-01

The surfaces of nodular and gray cast iron have been modified by CO 2 laser processing for enhanced hardness and erosion resistance. Control of the near-surface microstructure was achieved primarily by controlling resolidification of the laser melted layer through variations in laser beam/target interaction time and beam power density. Typical interaction times and power densities used were 5 msec and 500 kW/cm 2 . Two basic kinds of microstructure can be produced-a feathery microstructure with high hardness (up to 1245 HV) and a dendritic microstructure with a metastable, fully austenitic matrix and lower hardness (600 to 800 HV). Erosion testing was done using slurries of SiO 2 or SiC in water. Weight loss and crater profile measurements were used to evaluate the erosion characteristics of the various microstructures. Both ductile and gray cast iron showed marked improvement in erosion resistance after laser processing
Influence of the casting processing route on the corrosion behavior of dental alloys.

Science.gov (United States)

Galo, Rodrigo; Rocha, Luis Augusto; Faria, Adriana Claudia; Silveira, Renata Rodrigues; Ribeiro, Ricardo Faria; de Mattos, Maria da Gloria Chiarello

2014-12-01

Casting in the presence of oxygen may result in an improvement of the corrosion performance of most alloys. However, the effect of corrosion on the casting without oxygen for dental materials remains unknown. The aim of this study was to investigate the influence of the casting technique and atmosphere (argon or oxygen) on the corrosion behavior response of six different dental casting alloys. The corrosion behavior was evaluated by electrochemical measurements performed in artificial saliva for the different alloys cast in two different conditions: arc melting in argon and oxygen-gas flame centrifugal casting. A slight decrease in open-circuit potential for most alloys was observed during immersion, meaning that the corrosion tendency of the materials increases due to the contact with the solution. Exceptions were the Co-based alloys prepared by plasma, and the Co-Cr-Mo and Ni-Cr-4Ti alloys processed by oxidized flame, in which an increase in potential was observed. The amount of metallic ions released into the artificial saliva solution during immersion was similar for all specimens. Considering the pitting potential, a parameter of high importance when considering the fluctuating conditions of the oral environment, Co-based alloys show the best performance in comparison with the Ni-based alloys, independent of the processing route. Copyright © 2014 Elsevier B.V. All rights reserved.
Microstructural evolution and wear characteristics of equal channel angular pressing processed semi-solid-cast hypoeutectic aluminum alloys

International Nuclear Information System (INIS)

Thuong, Nguyen Van; Zuhailawati, Hussain; Seman, Anasyida Abu; Huy, Tran Duc; Dhindaw, Brij Kumar

2015-01-01

Highlights: • We produced aluminum feedstock for ECAP by two casting techniques: conventional and with cooling slope. • Globular α-Al phase was found in cooling slope sample compared to dendritic in the conventional. • After ECAP uniform Si particles distribution and fine α-Al were observed for cooling slope. • We observed significant improvement in wear resistance of ECAPed sample produced by cooling slope. - Abstract: This work investigated the microstructural evolution of Al–7Si–Mg alloy cast semi-solid using a cooling slope as well as conventional casting followed by equal channel angular pressing (ECAP) in a 120° die. Feed materials were prepared for ECAP by cooling slope casting and by conventional casting. The microstructure of the processed alloys extruded was observed by optical microscope and by transmission electron microscope, and their hardness and wear resistance were evaluated. After ECAP processing, the primary α-Al phase tended to be elongated while the Si particles became fragmented and more nearly globular in shape and uniform in size than in the as-cast sample. The microstructure of the cooling slope-cast ECAPed samples was more homogenous than that of the conventionally cast ECAPed sample. The α-Al phase sub-grains were refined to sub-micrometer sizes for samples cast by both methods after ECAP. The hardness of the cooling slope-cast ECAPed sample was also higher than that of the conventionally cast ECAPed sample. The wear resistance of the alloy improved after cooling slope casting and ECAP processing
Antimicrobial polymer films for food packaging

Science.gov (United States)

Concilio, S.; Piotto, S.; Sessa, L.; Iannelli, P.; Porta, A.; Calabrese, E. C.; Galdi, M. R.; Incarnato, L.

2012-07-01

New antimicrobial polymeric systems were realized introducing new antimicrobial azo compounds in PP and LDPE matrices. The polymeric materials containing different percentage of azo compounds were mold-casted and the obtained film were tested in vitro against Gram+ and Gram- bacteria and fungi. These results hold promise for the fabrication of bacteria-resistant polymer films by means of simple melt processing with antimicrobial azo-dyes.
TECHNOLOGICAL PROCESSES OF PRODUCTION OF THE MASS FUNCTION CAST BARS

Directory of Open Access Journals (Sweden)

A. N. Krutilin

2012-01-01

Full Text Available A number of scientifically grounded technical decisions, the whole set of which has enabled to create technological processes of production of high-quality cast bars of mass appointment is offered.
Processing of Advanced Cast Alloys for A-USC Steam Turbine Applications

Science.gov (United States)

Jablonski, Paul D.; Hawk, Jeffery A.; Cowen, Christopher J.; Maziasz, Philip J.

2012-02-01

The high-temperature components within conventional supercritical coal-fired power plants are manufactured from ferritic/martensitic steels. To reduce greenhouse-gas emissions, the efficiency of pulverized coal steam power plants must be increased to as high a temperature and pressure as feasible. The proposed steam temperature in the DOE/NETL Advanced Ultra Supercritical power plant is high enough (760°C) that ferritic/martensitic steels will not work for the majority of high-temperature components in the turbine or for pipes and tubes in the boiler due to temperature limitations of this class of materials. Thus, Ni-based superalloys are being considered for many of these components. Off-the-shelf forged nickel alloys have shown good promise at these temperatures, but further improvements can be made through experimentation within the nominal chemistry range as well as through thermomechanical processing and subsequent heat treatment. However, cast nickel-based superalloys, which possess high strength, creep resistance, and weldability, are typically not available, particularly those with good ductility and toughness that are weldable in thick sections. To address those issues related to thick casting for turbine casings, for example, cast analogs of selected wrought nickel-based superalloys such as alloy 263, Haynes 282, and Nimonic 105 have been produced. Alloy design criteria, melt processing experiences, and heat treatment are discussed with respect to the as-processed and heat-treated microstructures and selected mechanical properties. The discussion concludes with the prospects for full-scale development of a thick section casting for a steam turbine valve chest or rotor casing.
A comprehensive evaluation of the toxicology of the "Deli" cast sheet process used in experimental cigarettes.

Science.gov (United States)

Coggins, Christopher R E; Merski, Jerome A; Oldham, Michael J

2013-01-01

Manufacture of cigarettes results in tobacco by-products, some of which can be processed and added back to cigarettes. Such additions (known as reconstituted tobacco or reconstituted leaf) have been shown to reduce tar yields. A new process (termed "Deli" cast sheet) is a potential refinement of the reconstitution process. Compare toxicity of smoke from experimental cigarettes made with reconstituted leaf with that from cigarettes made with Deli cast sheet. Analytical chemistry, Salmonella mutagenicity and cytotoxicity assays were used to evaluate the composition biological activity of mainstream smoke from experimental cigarettes made with Deli cast sheet or with reconstituted leaf. The effect of different amounts of guar and propylene glycol in Deli cast sheet was also evaluated. Small increases in the amount of nitrogen oxides were found as a result of inclusion of the Deli cast sheet when compared with reconstituted leaf; no differences in cytotoxicity or mutagenicity were found. The Deli process neither significantly modified chemical composition of smoke nor affected its biological activity, as measured by the mutagenicity and cytotoxicity assays used here.
Multi-Objective Optimization of Squeeze Casting Process using Genetic Algorithm and Particle Swarm Optimization

Directory of Open Access Journals (Sweden)

Patel G.C.M.

2016-09-01

Full Text Available The near net shaped manufacturing ability of squeeze casting process requiresto set the process variable combinations at their optimal levels to obtain both aesthetic appearance and internal soundness of the cast parts. The aesthetic and internal soundness of cast parts deal with surface roughness and tensile strength those can readily put the part in service without the requirement of costly secondary manufacturing processes (like polishing, shot blasting, plating, hear treatment etc.. It is difficult to determine the levels of the process variable (that is, pressure duration, squeeze pressure, pouring temperature and die temperature combinations for extreme values of the responses (that is, surface roughness, yield strength and ultimate tensile strength due to conflicting requirements. In the present manuscript, three population based search and optimization methods, namely genetic algorithm (GA, particle swarm optimization (PSO and multi-objective particle swarm optimization based on crowding distance (MOPSO-CD methods have been used to optimize multiple outputs simultaneously. Further, validation test has been conducted for the optimal casting conditions suggested by GA, PSO and MOPSO-CD. The results showed that PSO outperformed GA with regard to computation time.
Demerit control chart as a decision support tool in quality control of ductile cast-iron casting process

Directory of Open Access Journals (Sweden)

Sika Robert

2017-01-01

Full Text Available In many industrial areas the product quality can be unequivocally assigned to classes such as: “good”, “bad” or “to repair”. In case of casting processes, the product is approved to sales considering customer’s requirements. Except for common characteristics, such as structure, compactness and mechanical properties, physical state of the product is also important. This state is assessed by checking occurrence of specific kind of defects. They are often conditionally accepted by a customer if they do not have any influence on functionality of the product (e.g. negative adhesive and cohesive phenomena, fatigue strength, thermal shocks. Authors’ experience shows that current registering of the most frequently occurring defects and comparing them to customers’ requirements can be very useful and help a quality engineer to control the casting process. They suggest using the Demerit Control Chart (DCC, according to authors’ own methodology, in aspect of information about the castings accepted conditionally by a customer (DCC-recognition. DCC-recognition can be used to assess this quality by monitoring the value of just one aggregated measure for all kinds of defects instead of using a single attribute control chart for each of them. The test version of this tool considering severity of defects proved to be useful in one of the European foundries.
The Through Process Simulation of Mold filling, Solidification, and Heat Treatment of the Al Alloy Bending Beam Low-pressure Casting

International Nuclear Information System (INIS)

Yin, Yajun; Guo, Zhao; Wang, Huan; Liao, Dunming; Chen, Tao; Zhou, Jianxin

2015-01-01

The research on the simulation for the through process of low-pressure casting and heat treatment is conducive to combine information technology and advanced casting technology, which will help to predict the defects and mechanical properties of the castings in the through process. In this paper, we focus on the simulation for through process of low-pressure casting and heat treatment of ZL114A Bending beam. Firstly, we analyzethe distribution of the shrinkage and porosities in filling and solidification process, and simulate the distribution of stress and strain in the late solidification of casting. Then, the numerical simulation of heat treatment process for ZL114A Bending beam is realized according to the heat treatment parameters and the corresponding simulation results of temperature field, stress, strain, and aging performance are given. Finally, we verify that simulation platform for the through process of low-pressure casting and heat treatment can serve the production practice perfectly and provide technical guidance and process optimization for the through process of low-pressure casting and heat treatment. (paper)
Process to Continuously Melt, Refine and Cast High Quality Steel

Energy Technology Data Exchange (ETDEWEB)

None

2005-09-01

The purpose of this project is to conduct research and development targeted at designing a revolutionary steelmaking process. This process will deliver high quality steel from scrap to the casting mold in one continuous process and will be safer, more productive, and less capital intensive to build and operate than conventional steelmaking. The new process will produce higher quality steel faster than traditional batch processes while consuming less energy and other resources.
Research on plant of metal fuel fabrication using casting process

International Nuclear Information System (INIS)

Senda, Yasuhide; Mori, Yukihide

2003-12-01

This document presents the plant concept of metal fuel fabrication system (38tHM/y) using casting process in electrolytic recycle, which based on recent studies of its equipment design and quality control system. And we estimate the cost of its construction and operation, including costs of maintenance, consumed hardware and management of waste. The content of this work is as follows. (1) Designing of fuel fabrication equipment: We make material flow diagrams of the fuel fabrication plant and rough designs of the injection casting furnace, demolder and inspection equipment. (2) Designing of resolution system of liquid waste, which comes from analytical process facility. Increased analytical items, we rearrange analytical process facility, estimate its chemicals and amount of waste. (3) Arrangement of equipments: We made a arrangement diagram of the metal fuel fabrication equipments in cells. (4) Estimation of cost data: We estimated cost to construct the facility and to operate it. (author)
Melting and casting of FeAl-based cast alloy

Energy Technology Data Exchange (ETDEWEB)

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

1998-11-01

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

Performance evaluation of solid oxide fuel cells with thin film electrolyte fabricated by binder-assisted slurry casting

Energy Technology Data Exchange (ETDEWEB)

Guo, W.M.; Liu, X.M.; Li, L.J. [Department of Biological and Chemical Engineering, Guangxi University of Technology, Liuzhou 545006 (China); Xiao, Y.F. [Department of Stomatology, Liuzhou Maternity and Child Health Hospital, Liuzhou 545001 (China); Chen, Y. [School of Yingdong Life Science, Shaoguan University, Shaoguan 512005 (China)

2011-10-15

A gas-tight yttria-stabilized zirconia (YSZ) electrolyte film was fabricated on porous NiO-YSZ anode substrates by a binder-assisted slurry casting technique. The scanning electron microscope (SEM) results showed that the YSZ film was relatively dense with a thickness of 10 {mu}m. La{sub 0.8}Sr{sub 0.2}MnO{sub 3} (LSM)-YSZ was applied to cathode using a screen-print technique and the single fuel cells were tested in a temperature range from 600 to 800 C. An open circuit voltage (OCV) of over 1.0 V was observed. The maximum power densities at 600, 700, and 800 C were 0.13, 0.44, and 1.1 W cm{sup -2}, respectively. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Feasibility of large volume casting cementation process for intermediate level radioactive waste

International Nuclear Information System (INIS)

Chen Zhuying; Chen Baisong; Zeng Jishu; Yu Chengze

1988-01-01

The recent tendency of radioactive waste treatment and disposal both in China and abroad is reviewed. The feasibility of the large volume casting cementation process for treating and disposing the intermediate level radioactive waste from spent fuel reprocessing plant in shallow land is assessed on the basis of the analyses of the experimental results (such as formulation study, solidified radioactive waste properties measurement ect.). It can be concluded large volume casting cementation process is a promising, safe and economic process. It is feasible to dispose the intermediate level radioactive waste from reprocessing plant it the disposal site chosen has resonable geological and geographical conditions and some additional effective protection means are taken
Film processing characteristics of nano gold suitable for conductive application on flexible substrates

International Nuclear Information System (INIS)

Gupta, Ashish; Mandal, Saumen; Katiyar, Monica; Mohapatra, Yashowanta N.

2012-01-01

In spite of large number of studies and wide use of thiol encapsulated gold nanoparticles, the mechanism of their transformation to thin gold films for conductive applications is not as yet well understood. In order to understand and optimize the process of conversion of nanoparticle based ink for printing on plastic substrates, we synthesize and study thiolated Au nanoparticles, with average size of 2 nm, but with differing carbon chain length viz. butane (Au-C4), hexane (Au-C6) and octane (Au-C8). The link between the properties of Au nanoparticle and its transformation from nonconductive gold nanoparticle ink to conductive gold film is studied using a variety of techniques such as thermo gravimetric analysis (TGA), X-ray diffraction (XRD), atomic force microscopy, scanning electron microscopy and electrical conductivity measurements. A combined study of the shape of solution TGA and differential thermal analysis indicates occurrence of two distinct processes corresponding to disentanglement and debonding of thiol chains preceding the sintering of nanoparticles. The lowest sintering temperature is observed to be approximately 155 °C for chain length C4, and hence Au-C4 on polyethylene terephthalate substrates is studied in detail. Though XRD peaks of thick drop-cast films on polyethylene terephthalate substrate show increasing peak intensity with annealing temperature as expected, for spin coated thin films, in contrast, the peak intensity decreases with increase in annealing temperature. Electrical conductivity of the thin films is comparable to bulk gold after conversion, but decreases with increase in annealing temperature demonstrating the usefulness of insights obtained in the study for optimization of annealing schedules. - Highlights: ► Sintering of alkanethiol capped Au nanoparticles is chainlength dependent. ► Sintering temperature depends on thiol debonding. ► Butanethiol capped Au nanoparticles are the most suitable for flexible substrates. �
Microstructure analysis of AISI 304 stainless steel produced by twin-roll thin strip casting process

Institute of Scientific and Technical Information of China (English)

无

2007-01-01

The microstructure of AISI 304 austenite stainless steel fabricated by the thin strip casting process were investigated using optical microscope, scanning electron microscope (SEM), transmission electron microscope (TEM), and X-ray diffraction (XRD).The microstructures of the casting strips show a duplex structure consisting of delta ferrite and austenite. The volume fraction of the delta ferrite is about 9.74vol% at the center and 6.77vol% at the surface of the casting thin strip, in vermicular and band shapes. On account of rapid cooling and solidification in the continuous casting process, many kinds of inclusions and precipitates have been found. Most of the inclusions and precipitates are spherical complex compounds consisting of oxides, such as, SiO2, MnO, Al2O3,Cr2O3,and FeO or their multiplicity oxides of MnO·Al2O3,2FeO·SiO2, and 2MnO·SiO2. Many defects including dislocations and stacking faults have also formed during the rapid cooling and solidification process, which is helpful to improve the mechanical properties of the casting strips.
Fixed-film processes. Part 2

International Nuclear Information System (INIS)

Canziani, R.

1999-01-01

Recently, full scale fixed-film or mixed suspended have been applied in many wastewater treatments plants. These processes no longer depend on biomass settle ability and can be used to improve the performance of existing plants as required by more stringent discharge permit limits, especially for nutrients suspended solids. Also, processes may work at high rates making is possible to build small footprint installations. Fixed-film processes include trickling filters (and combined suspended and fixed-films processes), rotating biological contactors, biological aerated submerged, filters moving bed reactors, fluidized bed reactors. In the first part, the theoretical based governing fixed-film processes are briefly outlined, with some simple examples of calculations, underlining the main differences with conventional activate sludge processes. In the second part, the most common types of reactors are reviewed [it
Development of Integrated Die Casting Process for Large Thin-Wall Magnesium Applications

Energy Technology Data Exchange (ETDEWEB)

Carter, Jon T. [General Motors LLC, Warren, MI (United States); Wang, Gerry [Meridian Lightweight Technologies, Plymouth MI (United States); Luo, Alan [General Motors LLC, Warren, MI (United States)

2017-11-29

The purpose of this project was to develop a process and product which would utilize magnesium die casting and result in energy savings when compared to the baseline steel product. The specific product chosen was a side door inner panel for a mid-size car. The scope of the project included: re-design of major structural parts of the door, design and build of the tooling required to make the parts, making of parts, assembly of doors, and testing (both physical and simulation) of doors. Additional work was done on alloy development, vacuum die casting, and overcasting, all in order to improve the performance of the doors and reduce cost. The project achieved the following objectives: 1. Demonstrated ability to design a large thin-wall magnesium die casting. 2. Demonstrated ability to manufacture a large thin-wall magnesium die casting in AM60 alloy. 3. Tested via simulations and/or physical tests the mechanical behavior and corrosion behavior of magnesium die castings and/or lightweight experimental automotive side doors which incorporate a large, thin-wall, powder coated, magnesium die casting. Under some load cases, the results revealed cracking of the casting, which can be addressed with re-design and better material models for CAE analysis. No corrosion of the magnesium panel was observed. 4. Using life cycle analysis models, compared the energy consumption and global warming potential of the lightweight door with those of a conventional steel door, both during manufacture and in service. Compared to a steel door, the lightweight door requires more energy to manufacture but less energy during operation (i.e., fuel consumption when driving vehicle). Similarly, compared to a steel door, the lightweight door has higher global warming potential (GWP) during manufacture, but lower GWP during operation. 5. Compared the conventional magnesium die casting process with the “super-vacuum” die casting process. Results achieved with cast tensile bars suggest some
Microstructure, process, and tensile property relationships in an investment cast near-γTiAl alloy

International Nuclear Information System (INIS)

Jones, P.E.; Porter, W.J. III.; Keller, M.M.; Eylon, D.

1992-01-01

The brittle nature of near-γ TiAl alloys makes fabrication difficult. This paper reports on developing near-net shape technologies, such as investment casting, for these alloys which is one of the essential approached to their commercial introduction. The near-γ TiAl alloy Ti-48Al-2Nb-2Cr (a%) is investment cast with two cooling rates. The effect of casting cooling rate on the fill and surface integrity was studied for complex shape thin walled components. Block and bar castings are hot isostatically pressed (HIP'd) and heat treated to produce duplex (lamellar + equiaxed) microstructures for mechanical property evaluation. The relationships between the casting conditions, microstructures, and tensile properties are studied. The strength and elongation below the ductile to brittle transition temperature are dependent on the casting cooling rate and section size. The tensile properties improved with faster cooling during the casting process as a result of microstructural refinement. Faster cooled castings are more fully transformed to a duplex structure during post-casting heat treatments. Above the ductile to brittle transition temperature the effect of casting cooling rate on tensile properties is less pronounced
Numerical simulation of casting process to assist in defects reduction in complex steel tidal power component

International Nuclear Information System (INIS)

Guo, E J; Zhao, S C; Wang, L P; Wu, T; Xin, B P; Tan, J J; Jia, H L

2016-01-01

In order to reduce defects and improve casting quality, ProCAST software is performed to study the solidification process of discharge bowl. Simulated results of original casting process show that the hot tearing is serious at the intersection of blades and outer or inner rings. The shrinkage porosity appears at the bottom of discharge bowl and the transition area of wall thickness. Based on the formation mechanisms of the defects, the structure of chills attached on the outer surface of discharge bowl casting is optimized. The thickness of chills ranges from 25mm to 35mm. The positions of chills corresponded to the outer surface of the T-shaped parts. Compared to the original casting design (without chills), the hot tearing and shrinkage porosity of the discharge bowl are greatly improved with addition of chills. (paper)
A comparative study on cellulose nanocrystals extracted from bleached cotton and flax and used for casting films with glycerol and sorbitol plasticisers.

Science.gov (United States)

Csiszár, Emilia; Nagy, Sebestyén

2017-10-15

Cellulose nanocrystals (CNCs) were released from bleached cotton and flax by a sulphuric acid hydrolysis with about 40 and 34% yield, respectively. The rod-like cotton-CNC particles were slightly longer and wider and had a less pronounced aggregation ability in aqueous suspension than the flax-CNC ones. Films were cast from the CNC suspensions with sorbitol and glycerol plasticisers. The concept behind this research was to explore how the plasticisers - with similar structure but different molecular weight - and their concentrations affect the perceptible and measured properties of CNC films. Results revealed that the type of plasticiser determined the morphology and the optical and tensile properties of films. The best quality CNC film with an averaged thickness of 50μm was obtained with 20% sorbitol from cotton-CNC. It was proved that behaviour of sorbitol and glycerol plasticisers in CNC films was very similar to that reported previously for starch films. Copyright © 2017 Elsevier Ltd. All rights reserved.
Super-rapid medical film processing system

International Nuclear Information System (INIS)

Honda, C.; Iwata, M.; Nozaki, H.

1988-01-01

A new super-rapid medical film processing system cuts processing time from 90 to 45 seconds, a critical advantage in traumatic injury, surgical operation, and other time-vital applications. The system consists of new films new processing chemicals (developer and fixer), and a new high-speed medical film processor. The system's creation is made possible by three new technologies. In film, multilayered monodispersed grains reduce processing time. In processing chemicals, an innovative design maximizes processing speed. And in the processor itself, a new drying apparatus increases drying efficiency. Together, these technologies achieve 45-second processing without degradation of image quality
Oxygen diffusion in bilayer polymer films

DEFF Research Database (Denmark)

Poulsen, Lars; Zebger, Ingo; Tofte, Jannik Pentti

2004-01-01

Experiments to quantify oxygen diffusion have been performed on polymer samples in which a film of poly(ethylene-co-norbornene) was cast onto a film of polystyrene which, in turn, was cast onto an oxygen-impermeable substrate. In the technique employed, the time evolution of oxygen transport...... through the film of poly(ethylene-co-norbornene) and into the polystyrene film was monitored using the phosphorescence of singlet oxygen as a spectroscopic probe. To analyze the data, it was necessary to solve Fick's second law of diffusion for both polymer films. Tractable analytical and numerical...
DC-magnetron sputtering of ZnO:Al films on (00.1)Al2O3 substrates from slip-casting sintered ceramic targets

International Nuclear Information System (INIS)

Miccoli, I.; Spampinato, R.; Marzo, F.; Prete, P.; Lovergine, N.

2014-01-01

Highlights: • ZnO:Al was DC-sputtered on sapphire >350 °C by slip-casting sintered AZO target. • Films are highly (00.1)-oriented, smooth and transparent in the NIR–visible range. • Films growth rate decreases with temperature, while their grain size increases. • A high temperature reduction for sticking coefficients of impinging species is proved. • We prove that Thornton model does not apply to high-temperature DC-sputtered ZnO. - Abstract: High (>350 °C) temperature DC-sputtering deposition of ZnO:Al thin films onto single-crystal (00.1) oriented Al 2 O 3 (sapphire) substrates is reported, using a ultrahigh-density, low-resistivity and low-cost composite ceramic target produced by slip-casting (pressureless) sintering of ZnO–Al 2 O 3 (AZO) powders. The original combination of high-angle θ–2θ (Bragg–Brentano geometry) X-ray diffraction with low angle θ–2θ X-ray reflectivity (XRR) techniques allows us to define the AZO target composition and investigate the structural properties and surface/interface roughness of as-sputtered ZnO:Al films; besides, the growth dynamics of ZnO:Al is unambiguously determined. The target turned out composed of the sole wurtzite ZnO and spinel ZnAl 2 O 4 phases. X-ray diffraction analyses revealed highly (00.1)-oriented (epitaxial) ZnO:Al films, the material mean crystallite size being in the 13–20 nm range and increasing with temperature between 350 °C and 450 °C, while the film growth rate (determined via XRR measurements) decreases appreciably. XRR spectra also allowed to determine rms surface roughness <1 nm for present films and showed ZnO:Al density changes by only a few percent between 350 °C and 450 °C. The latter result disproves the often-adopted Thornton model for the description of the sputter-grown ZnO films and instead points out toward a reduction of the sticking coefficients of impinging species, as the main origin of film growth rate and grain size dependence with temperature. Zn
Dimensional control of die castings

Science.gov (United States)

Karve, Aniruddha Ajit

The demand for net shape die castings, which require little or no machining, is steadily increasing. Stringent customer requirements are forcing die casters to deliver high quality castings in increasingly short lead times. Dimensional conformance to customer specifications is an inherent part of die casting quality. The dimensional attributes of a die casting are essentially dependent upon many factors--the quality of the die and the degree of control over the process variables being the two major sources of dimensional error in die castings. This study focused on investigating the nature and the causes of dimensional error in die castings. The two major components of dimensional error i.e., dimensional variability and die allowance were studied. The major effort of this study was to qualitatively and quantitatively study the effects of casting geometry and process variables on die casting dimensional variability and die allowance. This was accomplished by detailed dimensional data collection at production die casting sites. Robust feature characterization schemes were developed to describe complex casting geometry in quantitative terms. Empirical modeling was utilized to quantify the effects of the casting variables on dimensional variability and die allowance for die casting features. A number of casting geometry and process variables were found to affect dimensional variability in die castings. The dimensional variability was evaluated by comparisons with current published dimensional tolerance standards. The casting geometry was found to play a significant role in influencing the die allowance of the features measured. The predictive models developed for dimensional variability and die allowance were evaluated to test their effectiveness. Finally, the relative impact of all the components of dimensional error in die castings was put into perspective, and general guidelines for effective dimensional control in the die casting plant were laid out. The results of
Standard digital reference images for inspection of aluminum castings

CERN Document Server

American Society for Testing and Materials. Philadelphia

2005-01-01

1.1 These digital reference images illustrate the types and degrees of discontinuities that may be found in aluminum-alloy castings. The castings illustrated are in thicknesses of 1/ 4 in. [6.35 mm] and 3/4 in. [19.1mm]. 1.2 All areas of this standard may be open to agreement between the cognizant engineering organization and the supplier, or specific direction from the cognizant engineering organization. These items should be addressed in the purchase order or the contract. 1.3 The values stated in inch-pound units are to be regarded as standard. 1.4 These digital reference images are not intended to illustrate the types and degrees of discontinuities found in aluminum-alloy castings when performing film radiography. If performing film radiography of aluminum-alloy castings, refer to Reference Radiographs E 155. This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and he...
Dehydration of moulding sand in simulated casting process examined with neutron radiography

Energy Technology Data Exchange (ETDEWEB)

Schillinger, B., E-mail: Burkhard.Schillinger@frm2.tum.de [Technische Universitaet Muenchen, FRM II and Faculty for Physics E21, Lichtenbergstr. 1, 85748 Garching (Germany); Calzada, E. [Technische Universitaet Muenchen, FRM II and Faculty for Physics E21, Lichtenbergstr. 1, 85748 Garching (Germany); Eulenkamp, C.; Jordan, G.; Schmahl, W.W. [Ludwig-Maximilians-Universitaet Muenchen, Department fuer Geo- und Umweltwissenschaften, Sektion Kristallographie, Theresienstr. 41, 80333 Muenchen (Germany)

2011-09-21

Natural bentonites are an important material in the casting industry. Smectites as the main component of bentonites plasticize and stabilise sand moulds. Pore water as well as interlayer water within the smectites are lost as a function of time, location and temperature. Although rehydration of the smectites should be a reversible process, the industrially dehydrated smectites lose their capability to reabsorb water. This limits the number of possible process cycles of the mould material. A full understanding of the dehydration process would help to optimise the amount of fresh material to be added and thus save resources. A simulated metal casting was investigated with neutron radiography at the ANTARES neutron imaging facility of the FRM II reactor of Technische Universitaet Muenchen, Germany.
Predicting the optimal process window for the coating of single-crystalline organic films with mobilities exceeding 7 cm2/Vs.

Science.gov (United States)

Janneck, Robby; Vercesi, Federico; Heremans, Paul; Genoe, Jan; Rolin, Cedric

2016-09-01

Organic thin film transistors (OTFTs) based on single crystalline thin films of organic semiconductors have seen considerable development in the recent years. The most successful method for the fabrication of single crystalline films are solution-based meniscus guided coating techniques such as dip-coating, solution shearing or zone casting. These upscalable methods enable rapid and efficient film formation without additional processing steps. The single-crystalline film quality is strongly dependent on solvent choice, substrate temperature and coating speed. So far, however, process optimization has been conducted by trial and error methods, involving, for example, the variation of coating speeds over several orders of magnitude. Through a systematic study of solvent phase change dynamics in the meniscus region, we develop a theoretical framework that links the optimal coating speed to the solvent choice and the substrate temperature. In this way, we can accurately predict an optimal processing window, enabling fast process optimization. Our approach is verified through systematic OTFT fabrication based on films grown with different semiconductors, solvents and substrate temperatures. The use of best predicted coating speeds delivers state of the art devices. In the case of C8BTBT, OTFTs show well-behaved characteristics with mobilities up to 7 cm2/Vs and onset voltages close to 0 V. Our approach also explains well optimal recipes published in the literature. This route considerably accelerates parameter screening for all meniscus guided coating techniques and unveils the physics of single crystalline film formation.
SLIP CASTING METHOD

Science.gov (United States)

Allison, A.G.

1959-09-01

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

Directory of Open Access Journals (Sweden)

O. G. Devojno

2013-01-01

Full Text Available The paper provides an analysis of ultrasonic surface plastic deformation and subsequent laser thermal strengthening of gray cast iron parts in the regime of hardening from a solid state with the purpose to obtain strengthened surface layers of bigger depth and less roughness of the processed surface. Program complex ANSYS 11.0 has been used for calculation of temperature fields induced by laser exposure. The appropriate regime of laser processing without surface fusion has been selected on the basis of the applied complex. The possibility of displacement in the bottom boundary of α–γ-transformation temperature for СЧ20 with 900 °С up to 800 °С is confirmed due to preliminary ultrasonic surface plastic deformation of the surface that allows to expand technological opportunities of laser quenching of gray cast iron from a solid state.
Birefringence dynamics of poly{1-[4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl, sodium salt} cast films

International Nuclear Information System (INIS)

Madruga, Carla; Filho, Paulo Alliprandini; Andrade, Marta M.; Goncalves, Manuel; Raposo, Maria; Ribeiro, Paulo A.

2011-01-01

Photoinduced birefringence creation/decay dynamics in poly{1-[4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl, sodium salt}cast films, has been characterized in the 5 to 100 mW writing laser power range at the wavelength of 514 nm. The maximum birefringence magnitude increased with laser beam power, being the largest value of 0.03, measured at 632.8 nm. Birefringence creation kinetics followed a biexponential behavior, where a slow process and a fast process could be clearly distinguished. The fast process accounted for more than 60% of birefringence. The time constants for both fast and slow processes decreased with increasing power of writing beam. Birefringence relaxation after removal of writing laser beam revealed to be independent of beam power and, was found to be ruled by two processes, described by a biexponential curve plus a constant term accounting for residual birefringence. A high residual birefringence signal of 85 ± 3% was attained, with the fast process contributing to 67% of decay from maximum value. The large values obtained for time constants for both birefringence creation and relaxation processes are believed to arise from stabilization of azo-group either by the formation of an ionic network, or by local short range interactions that are coming through as a result polyelectrolyte coiling due to its high degree of ionization.
Control of cast iron and casts manufacturing by Inmold method

Directory of Open Access Journals (Sweden)

S. Pietrowski

2009-07-01

Full Text Available In this paper the usability of cast iron spheroidizing process in mould control by ATD method as well as by ultrasonic method were presented. Structure of instrumentation needed for control form performance of cast iron spheroidizing by Inmold method was illustrated. Author, pointed out that amount of magnesium master alloy should obtain 0,8 ÷ 1,0% of mass in form at all. Such quantity of preliminary alloy assure of obtain of nodular graphite in cast iron. In consequence of this, is reduce the cast iron liquidus temperature and decrease of recalescence temperature of graphite-eutectic crystallization in compare with initial cast iron. Control of casts can be carried out by ultrasonic method. In plain cast iron, ferritic-pearlitic microstructure is obtaining. Additives of 1,5% Cu ensure pearlitic structure.

Preparation and optical characterization of DNA-riboflavin thin films

Science.gov (United States)

Paulson, Bjorn; Shin, Inchul; Kong, Byungjoo; Sauer, Gregor; Dugasani, Sreekantha Reddy; Khazaeinezhad, Reza; Jung, Woohyun; Joo, Boram; Oh, Kyunghwan

2016-09-01

Thin films of DNA biopolymer thin film are fabricated by a drop casting process on glass and silicon substrates, as well as freestanding. The refractive index is measured by elliposmetry and in bulk DNA film the refractive index is shown to be increased in the 600 to 900 nm DNA transparency window by doping with riboflavin. Further analysis with FT-IR, Raman, and XRD are used to determine whether binding between riboflavin and DNA occurs.
Clean Metal Casting

Energy Technology Data Exchange (ETDEWEB)

Makhlouf M. Makhlouf; Diran Apelian

2002-02-05

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

International Nuclear Information System (INIS)

Ramirez, A.; Morales, R.; Morales, A. J.; Ramos, A.; Solorio, G.

2006-01-01

This work written for illustrating the use of Monte Carlo methods and generating of random number in combination with the information of the simulation system of thermal behaviour described previously in order to reproduce in a computer the solidification process of the steel and simulate the formation of strictures of casting step by step. (Author). 12 refs
The thermal fatigue resistance of vermicular cast iron coupling with H13 steel units by cast-in process

International Nuclear Information System (INIS)

Wang, Chengtao; Zhou, Hong; Lin, Peng Yu; Sun, Na; Guo, Qingchun; Zhang, Peng; Yu, Jiaxiang; Liu, Yan; Wang, Mingxing; Ren, Luquan

2010-01-01

This paper focuses on improving the thermal fatigue resistance on the surface of vermicular cast iron coupling with inserted H13 steel blocks that had different cross sections, by cast-in processing. The microstructure of bionic units was examined by scanning electron microscope. Micro-hardness and thermal fatigue resistance of bionic samples with varied cross sections and spacings were investigated, respectively. Results show that a marked metallurgical bonding zone was produced at interface between the inserted H13 steel block and the parent material - a unique feature of the bionic structure in the vermicular cast iron samples. The micro-hardness of the bionic samples has been significantly improved. Thermal resistance of the samples with the circular cross section was the highest and the bionics sample with spacing of 2 mm spacing had a much longer thermal fatigue life, thus resulting in the improvement for the thermal fatigue life of the bionic samples, due to the efficient preclusion for the generation and propagation of crack at the interface of H13 block and the matrix.
The Behaviour of Bifilm Defects in Cast Al-7Si-Mg Alloy.

Science.gov (United States)

El-Sayed, Mahmoud Ahmed

2016-01-01

Double oxide films (bifilms) are significant defects in the casting of light alloys, and have been shown to decrease tensile and fatigue properties, and also to increase their scatter, making casting properties unreproducible and unreliable. A bifilm consists of doubled-over oxide films containing a gas-filled crevice and is formed due to surface turbulence of the liquid metal during handling and/or pouring. Previous studies has shown that the nature of oxide film defects may change with time, as the atmosphere inside the bifilm could be consumed by reaction with the surrounding melt, which may enhance the mechanical properties of Al alloy castings. As a proxy for a bifilm, an air bubble was trapped within an Al-7wt.%Si-0.3wt.%Mg (2L99) alloy melt, subjected to stirring. The effect of different parameters such as the holding time, stirring velocity and melt temperature on the change in gas composition of the bubble was investigated, using a design of experiments (DoE) approach. Also, the solid species inside the bubbles solidified in the melt were examined using SEM. The results suggested that both oxygen and nitrogen inside the bifilm would be consumed by reaction with the surrounding melt producing MgAl2O4 and AlN, respectively. Also, hydrogen was suggested to consistently diffuse into the defect. The reaction rates and the rate of H diffusion were shown to increase upon increasing the holding time and temperature, and stirring velocity. Such significant effect of the process parameters studied on the gaseous content of the bubble suggesting that a careful control of such parameters might lead to the deactivation of bifilm defects, or at least elimination of their deteriorous effect in light alloy castings.
Casting AISI 316 steel by gel cast

International Nuclear Information System (INIS)

Ozols, A; Thern, G; Rozenberg, S; Barreiro, M; Marajofsky, A

2004-01-01

The feasibility of producing AISI 316 steel components from their powders and avoiding their compaction is analyzed. A casting technique is tested that is similar to gel casting, used for ceramic materials. In the initial stage, the process consists of the formulation of a concentrated barbotine of powdered metal in a solution of water soluble organic monomers, which is cast in a mold and polymerized in situ to form a raw piece in the shape of the cavity. The process can be performed under controlled conditions using barbotines with a high monomer content from the acrylimide family. Then, the molded piece is slowly heated until the polymer is eliminated, and it is sintered at temperatures of 1160 o C to 1300 o C under a dry hydrogen atmosphere, until the desired densities are attained. The density and micro structure of the materials obtained are compared with those for the materials compacted and synthesized by the conventional processes. The preliminary results show the feasibility of the process for the production of certain kinds of structural components (CW)
Validation Studies of Temperature Distribution and Mould Filling Process for Composite Skeleton Castings

Directory of Open Access Journals (Sweden)

M. Cholewa

2007-07-01

Full Text Available In this work authors showed selected results of simulation and experimental studies on temperature distribution during solidification of composite skeleton casting and mould filling process (Fig. 4, 5, 6. The basic subject of the computer simulation was the analysis of ability of metal to fill the channels creating the skeleton shape and prepared in form of a core. Analysis of filling for each consecutive levels of the skeleton casting was conducted for simulation results and real casting. The skeleton casting was manufactured according to proposed technology (Fig. 5. Number of fully filled nodes in simulation was higher than obtained in experimental studies. It was observed in the experiment, that metal during pouring did not flow through the whole channel section, what enabled possibilities of reducing the channel section and pointed out the necessity of local pressure increase.
SPRAY CASTING

OpenAIRE

SALAMCI, Elmas

2010-01-01

ABSTRACT This paper is designed to provide a basic review of spray casting. A brief overview of the historical development of spray casting and the description of plant and equipment have been given. Following metallurgical characteristics of spray formed alloys, process parameters and solidification mechanism of spray deposition have been discussed in detail. Finally, microstructure and mechanical properties of the selected spray cast Al-Zn-Mg-Cu alloys have been presented and comp...
Self-supported ceramic substrates with directional porosity by mold freeze casting

DEFF Research Database (Denmark)

Gurauskis, Jonas; Graves, Christopher R.; Moreno, R.

2016-01-01

in a mold and applying directional freeze casting. Use of optimized suspension, cryoprotector additive and mold proved to deliver defect free ceramic films with high dimensional control. Microstructure analysis demonstrated the formation of desirable aligned porosity at macro-structural scale and resulted...... to be highly dependent on colloidal behaviour and freeze casting conditions. Manufactured green films were joined by lamination at room temperature and sintered to obtain symmetrical cells consisting of two porous self-supported substrate electrodes (∼420 μm) and dense yttria stabilized zirconia electrolyte...
Hydroxyapatite scaffolds processed using a TBA-based freeze-gel casting/polymer sponge technique.

Science.gov (United States)

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

2010-05-01

A novel freeze-gel casting/polymer sponge technique has been introduced to fabricate porous hydroxyapatite scaffolds with controlled "designer" pore structures and improved compressive strength for bone tissue engineering applications. Tertiary-butyl alcohol (TBA) was used as a solvent in this work. The merits of each production process, freeze casting, gel casting, and polymer sponge route were characterized by the sintered microstructure and mechanical strength. A reticulated structure with large pore size of 180-360 microm, which formed on burn-out of polyurethane foam, consisted of the strut with highly interconnected, unidirectional, long pore channels (approximately 4.5 microm in dia.) by evaporation of frozen TBA produced in freeze casting together with the dense inner walls with a few, isolated fine pores (<2 microm) by gel casting. The sintered porosity and pore size generally behaved in an opposite manner to the solid loading, i.e., a high solid loading gave low porosity and small pore size, and a thickening of the strut cross section, thus leading to higher compressive strengths.
Fixed-film processes. Part 1

International Nuclear Information System (INIS)

Canziani, R.

1999-01-01

Recently, full scale fixed-film or mixed suspended and fixed biomass bioreactors have been applied in many wastewater treatments plants. These process no longer depend on biomass settle ability and can be used to improve the performance of existing plants as required by more stringent discharge permit limits, especially for nutrients and suspended solid. Also, processes may work at high rates making it possible to build small footprint installations. Fixed-film process include trickling filter, moving bed reactors fluidized bed reactors. In the first part, the theoretical base governing fixed-film processes are briefly outlined with some simple examples of calculations underlining the main differences with conventional activated sludge processes [it
Characterisation of solution cast cellulose nanofibre – reinforced poly(lactic acid

Directory of Open Access Journals (Sweden)

2010-01-01

Full Text Available Cellulose nanofibres, 20 nm in diameter and 300 nm long, were prepared by acid hydrolysis of flax yarns. Composite films containing 2.5 and 5.0 wt% flax cellulose (FC fibres were prepared by solution casting of mixtures of poly(lactic acid (PLA solution and cellulose nanofibre suspension in chloroform. The resulting composite films and solution cast pure PLA film, with thickness of around 160 m, showed good transparency. For composites with 2.5 and 5.0 wt% FC, the tensile strength increased by 25 and 59% and tensile modulus by 42 and 47%, respectively, compared to pure PLA film. The composite film with 2.5 wt% FC combined high strength and ductility with tensile strength of 24.3 MPa and 70% elongation at break. Flax cellulose appeared to facilitate nucleation and subsequent crystallisation of PLA more effectively in the amorphous composites than in the crystalline composites.
Process and apparatus for irradiating film, and irradiated film

International Nuclear Information System (INIS)

1981-01-01

A process for irradiating film is described, which consists of passing the film through an electron irradiation zone having an electron reflection surface disposed behind and generally parallel to the film; and disposing within the irradiation zone adjacent the edges of the film a lateral reflection member for reflecting the electrons toward the reflection surface to further reflect the reflected electrons towards the adjacent edges of the film. (author)
Numerical Modeling of Fluid Flow in the Tape Casting Process

DEFF Research Database (Denmark)

Jabbari, Masoud; Hattel, Jesper Henri

2011-01-01

The flow behavior of the fluid in the tape casting process is analyzed. A simple geometry is assumed for running the numerical calculations in ANSYS Fluent and the main parameters are expressed in non-dimensional form. The effect of different values for substrate velocity and pressure force...
Casting of microstructured shark skin surfaces and possible applications on aluminum casting parts

Directory of Open Access Journals (Sweden)

Todor Ivanov

2011-02-01

Full Text Available Within the project Functional Surfaces via Micro- and Nanoscaled Structures?which is part of the Cluster of Excellence 揑ntegrative Production Technology?established and financed by the German Research Foundation (DFG, an investment casting process to produce 3-dimensional functional surfaces down to a structural size of 1 μm on near-net-shape-casting parts has been developed. The common way to realize functional microstructures on metallic surfaces is to use laser ablation, electro discharge machining or micro milling. The handicap of these processes is their limited productivity. The approach of this project to raise the efficiency is to use the investment casting process to replicate microstructured surfaces by moulding from a laser-microstructured grand master pattern. The main research objective deals with the investigation of the single process steps of the investment casting process with regard to the moulding accuracy. Actual results concerning making of the wax pattern, suitability of ceramic mould and core materials for casting of an AlSi7Mg0.3 alloy as well as the knock-out behavior of the shells are presented. By using of the example of an intake manifold of a gasoline race car engine, a technical shark skin surface has been realized to reduce the drag of the intake air. The intake manifold consists of an air-restrictor with a defined inner diameter which is microstructured with technical shark skin riblets. For this reason the inner diameter cannot be drilled after casting and demands a very high accuracy of the casting part. A technology for the fabrication and demoulding of accurate microstructured castings are shown. Shrinkage factors of different moulding steps of the macroscopic casting part as well as the microscopic riblet structure have been examined as well.
Stress strain modelling of casting processes in the framework of the control volume method

DEFF Research Database (Denmark)

Hattel, Jesper; Andersen, Søren; Thorborg, Jesper

1998-01-01

Realistic computer simulations of casting processes call for the solution of both thermal, fluid-flow and stress/strain related problems. The multitude of the influencing parameters, and their non-linear, transient and temperature dependent nature, make the calculations complex. Therefore the nee......, the present model is based on the mainly decoupled representation of the thermal, mechanical and microstructural processes. Examples of industrial applications, such as predicting residual deformations in castings and stress levels in die casting dies, are presented...... for fast, flexible, multidimensional numerical methods is obvious. The basis of the deformation and stress/strain calculation is a transient heat transfer analysis including solidification. This paper presents an approach where the stress/strain and the heat transfer analysis uses the same computational...... domain, which is highly convenient. The basis of the method is the control volume finite difference approach on structured meshes. The basic assumptions of the method are shortly reviewed and discussed. As for other methods which aim at application oriented analysis of casting deformations and stresses...
Modelling of solidification processing and continuous strip casting for copper-base alloys

Energy Technology Data Exchange (ETDEWEB)

Mahmoudi, Jafar [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Materials Processing

2000-04-01

An experimental and numerical study was carried out to investigate the solidification process in a copper continuous strip casting process. Heat flow and solidification process has been experimentally studied. Cooling curves during solidification were registered using a thermocouple of type K connected to a data acquisition system. Temperature measurements in the mould and cooling water were also performed. The numerical model considers a generalized set of mass, momentum and heat equations that is valid for the solid, liquid and solidification interval in the cast. A k-{epsilon} turbulence model, produced with the commercial program CFX, is used to analyse the solidification process of pure copper in the mould region of the caster. The fluid flow, temperature and heat flux distributions in the mould region of the caster were computed. The shape and location of the solidification front were also determined. The effects of the parameters such as heat transfer coefficient, casting speed, casting temperature, heat of fusion and specific heat on the shape and location of the solidification front and the heat transport at the mould-cast interface were investigated. The predicted temperature and heat flux distributions were compared with experimental measurements, and reasonable agreement was obtained. The solidification behaviour of pure copper and different copper base alloys has been studied. A series of solidification experiments using DTA furnace, mirror furnace and levitation technique were performed on different copper-base alloys. The undercooling, cooling rates of the liquid and the solid states, solidification times and temperatures were evaluated from the curves. The cooling curves for different samples were simulated using a FEM solidification program. It was found that the calculated values of the heat of fusion were much lower than the tabulated ones. The fraction of solid formed before quenching, in the DTA experiments, has been observed to be much higher
High-throughput creation of micropatterned PDMS surfaces using microscale dual roller casting

International Nuclear Information System (INIS)

DiBartolomeo, Franklin J; Ge, Ning; Trinkle, Christine A

2012-01-01

This work introduces microscale dual roller casting (MDRC), a novel high-throughput fabrication method for creating continuous micropatterned surfaces using thermosetting polymers. MDRC utilizes a pair of rotating, heated cylindrical molds with microscale surface patterns to cure a continuous microstructured film. Using unmodified polydimethylsiloxane as the thermosetting polymer, we were able to create optically transparent, biocompatible surfaces with submicron patterning fidelity. Compared to other roll-to-roll fabrication processes, this method offers increased flexibility in the types of materials and topography that can be generated, including dual-sided patterning, embedded materials and tunable film thickness. (paper)
Highly Conductive Cu 2– x S Nanoparticle Films through Room-Temperature Processing and an Order of Magnitude Enhancement of Conductivity via Electrophoretic Deposition

KAUST Repository

Otelaja, Obafemi O.

2014-11-12

© 2014 American Chemical Society. A facile room-temperature method for assembling colloidal copper sulfide (Cu2-xS) nanoparticles into highly electrically conducting films is presented. Ammonium sulfide is utilized for connecting the nanoparticles via ligand removal, which transforms the as-deposited insulating films into highly conducting films. Electronic properties of the treated films are characterized with a combination of Hall effect measurements, field-effect transistor measurements, temperature-dependent conductivity measurements, and capacitance-voltage measurements, revealing their highly doped p-type semiconducting nature. The spin-cast nanoparticle films have carrier concentration of ∼1019 cm-3, Hall mobilities of ∼3 to 4 cm2 V-1 s-1, and electrical conductivities of ∼5 to 6 S·cm-1. Our films have hole mobilities that are 1-4 orders of magnitude higher than hole mobilities previously reported for heat-treated nanoparticle films of HgTe, InSb, PbS, PbTe, and PbSe. We show that electrophoretic deposition (EPD) as a method for nanoparticle film assembly leads to an order of magnitude enhancement in film conductivity (∼75 S·cm-1) over conventional spin-casting, creating copper sulfide nanoparticle films with conductivities comparable to bulk films formed through physical deposition methods. The X-ray diffraction patterns of the Cu2-xS films, with and without ligand removal, match the Djurleite phase (Cu1.94S) of copper sulfide and show that the nanoparticles maintain finite size after the ammonium sulfide processing. The high conductivities reported are attributed to better interparticle coupling through the ammonium sulfide treatment. This approach presents a scalable room-temperature route for fabricating highly conducting nanoparticle assemblies for large-area electronic and optoelectronic applications.
Casting thermal simulation

International Nuclear Information System (INIS)

Shamsuddin bin Sulaiman

1994-01-01

The whole of this study is concerned with process simulation in casting processes. This study describes the application of the finite element method as an aid to simulating the thermal design of a high pressure die casting die by analysing the cooling transients in the casting cycle. Two types of investigation were carried out to model the linear and non-linear cooling behavior with consideration of a thermal interface effect. The simulated cooling for different stages were presented in temperature contour form. These illustrate the successful application of the Finite Element Method to model the process and they illustrate the significance of the thermal interface at low pressure

Mechanical and Barrier Properties of Semi Refined Kappa Carrageenan-based Composite Edible Film and Its Application on Minimally Processed Chicken Breast Fillet

Science.gov (United States)

Praseptiangga, D.; Maimuni, B. H.; Manuhara, G. J.; Muhammad, D. R. A.

2018-03-01

Kappa-carrageenan (KC) is one of the most interesting biopolymers that is composed of a linear chain of sulfated galactans and extracted from red seaweed, Kappaphycus alvarezii. It shows good potential for development as a source of biodegradable or edible films. However, KC films do not have good water vapor barrier properties, as they are intrinsically hydrophilic. Palmitic acid (PA) as hydrophobic material was incorporated into semi-refined kappa-carrageenan (SRKC) edible films in order to improve water vapor barrier properties. In this study, composite films based on SRKC incorporating PA were prepared and their applications on minimally processed chicken breast fillet were evaluated. Composite SRKC-based films with varying concentrations of PA (5%, 10%, and 15% w/w) were obtained by a solvent casting method. Their mechanical and barrier properties were investigated. Results showed that the incorporation of PA in films caused an increase in thickness, but decrease in water vapor transmission rate (WVTR) as the concentration of PA increased (from 5% to 15% w/w). Composite SRKC-based edible film incorporating 15% w/w of PA presented better water vapor barrier properties as compared to other films with 5% and 10% w/w PA incorporation. Thus, formulation containing 15% w/w PA was used as a wrapping material for film application on minimally processed chicken breast fillet. The application results showed that the incorporation of PA in film caused an effect (p 0.05) change the color of minimally processed chicken breast fillet.
Colour Metallography of Cast Iron - Chapter 3: Spheroidal Graphite Cast Iron (Ⅳ

Directory of Open Access Journals (Sweden)

Zhou Jiyang

2010-11-01

Full Text Available Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application and combine cast iron technology with some hi-techs (for example, computer technology. Nevertheless, cast iron is a multi-element and multi-phase alloy and has complex and variety of structures and still has great development potential in structure and property. For further studying and developing cast iron, theoretical research work is important promise, and the study on solidification process and control mechanism of graphite morphology is fundamental for improving property of cast iron and developing new type of cast iron. Metallography of cast iron normally includes two sections: liquid phase transformation and solid phase transformation. The book, Colour Metallography of Cast Iron, uses colour metallography technique to study solidification structures of cast irons: graphite, carbides, austenite and eutectics; and focuses on solidification processes. With progress of modern solidification theory, the control of material solidification process becomes important measure for improving traditional materials and developing new materials. Solidification structure not only influences mechanical and physical properties of cast iron, but also affects its internal quality. The book uses a large amount of colour photos to describe the formation of solidification structures and their relations. Crystallization phenomena, which cannot be displayed with traditional metallography, are presented and more phase transformation information is obtained from these colour
Colour Metallography of Cast Iron - Chapter 3: Spheroidal Graphite Cast Iron (Ⅰ

Directory of Open Access Journals (Sweden)

Zhou Jiyang

2010-02-01

Full Text Available Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application and combine cast iron technology with some hi-techs (for example, computer technology. Nevertheless, cast iron is a multi-element and multi-phase alloy and has complex and variety of structures and still has great development potential in structure and property. For further studying and developing cast iron, theoretical research work is important promise, and the study on solidification process and control mechanism of graphite morphology is fundamental for improving property of cast iron and developing new type of cast iron. Metallography of cast iron normally includes two sections: liquid phase transformation and solid phase transformation. The book, Colour Metallography of Cast Iron, uses colour metallography technique to study solidification structures of cast irons: graphite, carbides, austenite and eutectics; and focuses on solidification processes. With progress of modern solidification theory, the control of material solidification process becomes important measure for improving traditional materials and developing new materials. Solidification structure not only influences mechanical and physical properties of cast iron, but also affects its internal quality. The book uses a large amount of colour photos to describe the formation of solidification structures and their relations. Crystallization phenomena, which cannot be displayed with traditional metallography, are presented and more phase transformation information is obtained from these colour
Colour Metallography of Cast Iron - Chapter 4: Vermicular Graphite Cast Iron (Ⅱ

Directory of Open Access Journals (Sweden)

Zhou Jiyang

2011-05-01

Full Text Available Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application and combine cast iron technology with some hi-techs (for example, computer technology. Nevertheless, cast iron is a multi-element and multi-phase alloy and has complex and variety of structures and still has great development potential in structure and property. For further studying and developing cast iron, theoretical research work is important promise, and the study on solidification process and control mechanism of graphite morphology is fundamental for improving property of cast iron and developing new type of cast iron. Metallography of cast iron normally includes two sections: liquid phase transformation and solid phase transformation. The book, Colour Metallography of Cast Iron, uses colour metallography technique to study solidification structures of cast irons: graphite, carbides, austenite and eutectics; and focuses on solidification processes. With progress of modern solidification theory, the control of material solidification process becomes important measure for improving traditional materials and developing new materials. Solidification structure not only influences mechanical and physical properties of cast iron, but also affects its internal quality. The book uses a large amount of colour photos to describe the formation of solidification structures and their relations. Crystallization phenomena, which cannot be displayed with traditional metallography, are presented and more phase transformation information is obtained from these colour
Tailoring polymer films for solar-collection use, phase 1

Science.gov (United States)

Fouser, J. P.

1983-09-01

Several types of Polyacrylonitrile (PAN) polymers in film form that could meet the performance criteria with respect to thermal, ultraviolet, and tensile strength stability for use as exterior glazing in a low cost solar collector or for the internal heat exchange component were evaluated. Seven film specimens were tested. It is concluded that acrylonitrile homopolymer films when properly cast and processed have good mechanical properties, have long uv stability, and are usable for prolonged periods at 300 F.
Photocatalytic Graphene-TiO2 Thin Films Fabricated by Low-Temperature Ultrasonic Vibration-Assisted Spin and Spray Coating in a Sol-Gel Process

Directory of Open Access Journals (Sweden)

Fatemeh Zabihi

2017-05-01

Full Text Available In this work, we communicate a facile and low temperature synthesis process for the fabrication of graphene-TiO2 photocatalytic composite thin films. A sol-gel chemical route is used to synthesize TiO2 from the precursor solutions and spin and spray coating are used to deposit the films. Excitation of the wet films during the casting process by ultrasonic vibration favorably influences both the sol-gel route and the deposition process, through the following mechanisms. The ultrasound energy imparted to the wet film breaks down the physical bonds of the gel phase. As a result, only a low-temperature post annealing process is required to eliminate the residues to complete the conversion of precursors to TiO2. In addition, ultrasonic vibration creates a nanoscale agitating motion or microstreaming in the liquid film that facilitates mixing of TiO2 and graphene nanosheets. The films made based on the above-mentioned ultrasonic vibration-assisted method and annealed at 150 °C contain both rutile and anatase phases of TiO2, which is the most favorable configuration for photocatalytic applications. The photoinduced and photocatalytic experiments demonstrate effective photocurrent generation and elimination of pollutants by graphene-TiO2 composite thin films fabricated via scalable spray coating and mild temperature processing, the results of which are comparable with those made using lab-scale and energy-intensive processes.
Coccidioidomycosis among cast and crew members at an outdoor television filming event--California, 2012.

Science.gov (United States)

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

2014-04-18

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

Institute of Scientific and Technical Information of China (English)

无

2003-01-01

The transparent PVC films were prepared by tape casting. In the process of preparation, rare earth nitrate, as a kind of modifier, was added to the solution of PVC and THF. These PVC films were tested after being crosslinked by ultraviolet light. It is found that the mechanical and physical properties of all the PVC films modified by rare earth nitrate are greatly enhanced.
Modeling of solidification of MMC composites during gravity casting process

Directory of Open Access Journals (Sweden)

R. Zagórski

2013-04-01

Full Text Available The paper deals with computer simulation of gravity casting of the metal matrix composites reinforced with ceramics (MMC into sand mold. The subject of our interest is aluminum matrix composite (AlMMC reinforced with ceramic particles i.e. silicon carbide SiC and glass carbon Cg. The created model describes the process taking into account solidification and its influence on the distribution of reinforcement particles. The computer calculation has been carried out in 2D system with the use of Navier-Stokes equations using ANSYS FLUENT 13. The Volume of Fluid approach (VOF and enthalpy method have been used to model the air-fluid free surface (and also volume fraction of particular continuous phases and the solidification of the cast, respectively.
High thermoelectric power factor from multilayer solution-processed organic films

Science.gov (United States)

Zuo, Guangzheng; Andersson, Olof; Abdalla, Hassan; Kemerink, Martijn

2018-02-01

We investigate the suitability of the "sequential doping" method of organic semiconductors for thermoelectric applications. The method consists of depositing a dopant (F4TCNQ) containing solution on a previously cast semiconductor (P3HT) thin film to achieve high conductivity, while preserving the morphology. For very thin films (˜25 nm), we achieve a high power factor around 8 μW/mK-2 with a conductivity over 500 S/m. For the increasing film thickness, conductivity and power factor show a decreasing trend, which we attribute to the inability to dope the deeper parts of the film. Since thick films are required to extract significant power from thermoelectric generators, we developed a simple additive technique that allows the deposition of an arbitrary number of layers without significant loss in conductivity or power factor that, for 5 subsequent layers, remain at ˜300 S/m and ˜5 μW/mK-2, respectively, whereas the power output increases almost one order of magnitude as compared to a single layer. The efficient doping in multilayers is further confirmed by an increased intensity of (bi)polaronic features in the UV-Vis spectra.
Modelling the Cast Component Weight in Hot Chamber Die Casting using Combined Taguchi and Buckingham's π Approach

Science.gov (United States)

Singh, Rupinder

2018-02-01

Hot chamber (HC) die casting process is one of the most widely used commercial processes for the casting of low temperature metals and alloys. This process gives near-net shape product with high dimensional accuracy. However in actual field environment the best settings of input parameters is often conflicting as the shape and size of the casting changes and one have to trade off among various output parameters like hardness, dimensional accuracy, casting defects, microstructure etc. So for online inspection of the cast components properties (without affecting the production line) the weight measurement has been established as one of the cost effective method (as the difference in weight of sound and unsound casting reflects the possible casting defects) in field environment. In the present work at first stage the effect of three input process parameters (namely: pressure at 2nd phase in HC die casting; metal pouring temperature and die opening time) has been studied for optimizing the cast component weight `W' as output parameter in form of macro model based upon Taguchi L9 OA. After this Buckingham's π approach has been applied on Taguchi based macro model for the development of micro model. This study highlights the Taguchi-Buckingham based combined approach as a case study (for conversion of macro model into micro model) by identification of optimum levels of input parameters (based on Taguchi approach) and development of mathematical model (based on Buckingham's π approach). Finally developed mathematical model can be used for predicting W in HC die casting process with more flexibility. The results of study highlights second degree polynomial equation for predicting cast component weight in HC die casting and suggest that pressure at 2nd stage is one of the most contributing factors for controlling the casting defect/weight of casting.
Engineering design of centrifugal casting machine

Science.gov (United States)

Kusnowo, Roni; Gunara, Sophiadi

2017-06-01

Centrifugal casting is a metal casting process in which metal liquid is poured into a rotating mold at a specific temperature. Given round will generate a centrifugal force that will affect the outcome of the casting. Casting method is suitable in the manufacture of the casting cylinder to obtain better results. This research was performed to design a prototype machine by using the concept of centrifugal casting. The design method was a step-by-step systematic approach in the process of thinking to achieve the desired goal of realizing the idea and build bridges between idea and the product. Design process was commenced by the conceptual design phase and followed by the embodiment design stage and detailed design stage. With an engineering design process based on the method developed by G. E. Dieter, draft prototype of centrifugal casting machine with dimension of 550×450×400 mm, ¼ HP motor power, pulley and belt mechanism, diameter of 120-150mm, simultaneously with the characteristics of simple casting product, easy manufacture and maintenance, and relatively inexpensive, was generated.
Microstructures and formation mechanism of hypoeutectic white cast iron by isothermal electromagnetic rheocast process

Directory of Open Access Journals (Sweden)

Zhang Wanning

2010-05-01

Full Text Available An investigation was made on the evolution of microstructures of hypoeutectic white cast iron slurry containing 2.5wt.%C and 1.8wt.%Si produced by rheocasting in which the solidifying alloy was vigorously agitated by electromagnetic stirrer during isothermal cooling processes. The results indicated that under the proper agitating temperatures and speeds applied, the dendrite structures in white cast iron slurry were gradually evolved into spherical structures during a certain agitating time. It also revealed that the bent dendrites were formed by either convection force or by the growth of the dendrites themselves in the bending direction; then, as they were in solidifying, they were gradually being alternated into separated particles and into more spherical structures at the end of the isothermal cooling process. Especially, the dendrites were granulated as the bending process proceeding, which suggested that they were caused by unwanted elements such as sulfur and phosphor usually contained in engineering cast iron. Convective flow of the melt caused corrosion on the dendritic segments where they were weaker in strength and lower in melting temperature because of higher concentration of sulfur or phosphor. And the granulation process for such dendrites formed in the melt became possible under the condition. Certainly, dendrite fragments are another factors considerable to function for spherical particles formation. A new mechanism, regarding to the rheocast structure formation of white cast iron, was suggested based on the structural evolution observed in the study.
Effect of cast steel production metallurgy on the emergence of casting defects

Directory of Open Access Journals (Sweden)

L. Čamek

2016-10-01

Full Text Available The paper documents metallurgical possibilities of high alloy cast steel production in open induction medium frequency furnaces and an electric arc furnace in a gravity die casting foundry. The observation was focused on the emergence of gas defects in steel castings. The content of gases achieved during the metallurgical processes was evaluated for every unit of the production equipment and the casting ladle before casting into disposable sand moulds. The sand mould area was considered to be constant. The aim was to evaluate the current metallurgical possibilities of affecting the content of gases in high alloy cast steel in the current technical conditions of the foundry.
Cast iron - a predictable material

Directory of Open Access Journals (Sweden)

Jorg C. Sturm

2011-02-01

Full Text Available High strength compacted graphite iron (CGI or alloyed cast iron components are substituting previously used non-ferrous castings in automotive power train applications. The mechanical engineering industry has recognized the value in substituting forged or welded structures with stiff and light-weight cast iron castings. New products such as wind turbines have opened new markets for an entire suite of highly reliable ductile iron cast components. During the last 20 years, casting process simulation has developed from predicting hot spots and solidification to an integral assessment tool for foundries for the entire manufacturing route of castings. The support of the feeding related layout of the casting is still one of the most important duties for casting process simulation. Depending on the alloy poured, different feeding behaviors and self-feeding capabilities need to be considered to provide a defect free casting. Therefore, it is not enough to base the prediction of shrinkage defects solely on hot spots derived from temperature fields. To be able to quantitatively predict these defects, solidification simulation had to be combined with density and mass transport calculations, in order to evaluate the impact of the solidification morphology on the feeding behavior as well as to consider alloy dependent feeding ranges. For cast iron foundries, the use of casting process simulation has become an important instrument to predict the robustness and reliability of their processes, especially since the influence of alloying elements, melting practice and metallurgy need to be considered to quantify the special shrinkage and solidification behavior of cast iron. This allows the prediction of local structures, phases and ultimately the local mechanical properties of cast irons, to asses casting quality in the foundry but also to make use of this quantitative information during design of the casting. Casting quality issues related to thermally driven
Preparation and characterization of nanocomposite films from oil palm pulp nanocellulose/poly (Vinyl alcohol) by casting method.

Science.gov (United States)

Asad, Mohammad; Saba, Naheed; Asiri, Abdullah M; Jawaid, M; Indarti, Eti; Wanrosli, W D

2018-07-01

TEMPO-oxidize nanocellulose (TONC) suspension has been obtained from total chlorine free (TCF) oil palm empty-fruit-bunches (OPEFB) pulp using 4-acetamido-TEMPO (2,2,6,6-tetramethyl piperidin-1-oxyl) mediated oxidation with sodium hypochlorite and sodium bromide in water at 25 °C and pH 10. TONC suspension with varied content from 0.5 to 6% (w/w) reinforced polyvinyl alcohol (PVA) polymer based nanocomposite films were prepared by the casting method. The structural interaction between the TONC and PVA was characterized by the Fourier transform infrared (FT-IR) spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was found that the 4% (w/w) TONC content reinforced nanocomposite exhibited the highest tensile strength and modulus with an increase of 122% and 291% respectively, compared to PVA while the elongation at break decreased about 42.7%. Thermal stability of PVA based nanocomposite films was improved after incorporation of TONC. Incorporation of TONC in PVA film increases its crystallinity due to strongly linking between the hydroxyl groups of materials however considerable decreases beyond 2 wt% loading are observed. TONC incorporation beyond 2 wt% also reduces the melting temperature peaks and enthalpy of nanocomposite films. FT-IR spectra, NMR and SEM indicate that there is interaction between the TONC and PVA. Copyright © 2018 Elsevier Ltd. All rights reserved.
Viability of HEK 293 cells on poly-β-hydroxybutyrate (PHB) biosynthesized from a mutant Azotobacter vinelandii strain. Cast film and electrospun scaffolds.

Science.gov (United States)

Romo-Uribe, Angel; Meneses-Acosta, Angelica; Domínguez-Díaz, Maraolina

2017-12-01

Sterilization, cytotoxicity and cell viability are essential properties defining a material for medical applications and these characteristics were investigated for poly(β-hydroxybutyrate) (PHB) of 230kDa obtained by bacterial synthesis from a mutant strain of Azotobacter vinelandii. Cell viability was investigated for two types of PHB scaffolds, solution cast films and non-woven electrospun fibrous membranes, and the efficiency was compared against a culture dish. The biosynthesized PHB was sterilized by ultraviolet radiation and autoclave, it was found that the thermal properties and intrinsic viscosity remained unchanged indicating that the sterilization methods did not degrade the polymer. Sterilized scaffolds were then seeded with human embryonic kidney 293 (HEK 293) cells to evaluate the cytotoxic response. The cell viability of these cells was evaluated for up to six days, and the results showed that the cell morphology was normal, with no cytotoxic effects. The films and electrospun membranes exhibited over 95% cell viability whereas the viability in culture dishes reached only ca. 90%. The electrospun membrane, however, exhibited significantly higher cell density than the cast film suggesting that the fibrous morphology enables better nutrients transfer. The results indicate that the biosynthesized PHB stands UV and autoclave sterilization methods, it is biocompatible and non-toxic for cell growth of human cell lines. Furthermore, cell culture for up to 18 days showed that 62% and 90% of mass was lost for the film and fibrous electrospun scaffold, respectively. This is a favorable outcome for use in tissue engineering where material degradation, as tissue regenerates, is desirable. Copyright © 2017 Elsevier B.V. All rights reserved.
Chemically Crosslinked Hydrogel Film Leads to Integrated Flexible Supercapacitors with Superior Performance.

Science.gov (United States)

Wang, Kai; Zhang, Xiong; Li, Chen; Sun, Xianzhong; Meng, Qinghai; Ma, Yanwei; Wei, Zhixiang

2015-12-02

A high-strength poly(vinyl alcohol) chemical hydrogel (PCH) film is prepared by coupling covalent crosslinking with a film-casting process. Conducting polyaniline (PANI) is then embedded in the PCH film by in situ growth to form a composite film with a PANI-hydrogel-PANI configuration, which leads to a new conceptual flexible supercapacitor with all-in-one configuration that exhibits superior electrochemical performance and mechanical flexibility. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Refining processes in the copper casting technology

OpenAIRE

Rzadkosz, S.; Kranc, M.; Garbacz-Klempka, A.; Kozana, J.; Piękoś, M.

2015-01-01

The paper presents the analysis of technology of copper and alloyed copper destined for power engineering casts. The casts quality was assessed based on microstructure, chemical content analysis and strength properties tests. Characteristic deoxidising (Logas, Cup) and modifying (ODM2, Kupmod2) formulas were used for the copper where high electrical conductivity was required. Chosen examples of alloyed copper with varied Cr and Zr content were studied, and the optimal heat treatment parameter...
Modelling of flow phenomena during DC casting

NARCIS (Netherlands)

Zuidema, J.

2005-01-01

Modelling of Flow Phenomena during DC Casting Jan Zuidema The production of aluminium ingots, by semi-continuous casting, is a complex process. DC Casting stands for direct chill casting. During this process liquid aluminium transforms to solid aluminium while cooling down. This is not an

Numerical modelling of stresses and deformations in casting processes

DEFF Research Database (Denmark)

Hattel, Jesper Henri

1997-01-01

Keywords: Stresses and deformations, casting, governing equations, thermal strain, control volume method......Keywords: Stresses and deformations, casting, governing equations, thermal strain, control volume method...
Multiscale modeling for the prediction of casting defects in investment cast aluminum alloys

International Nuclear Information System (INIS)

Hamilton, R.W.; See, D.; Butler, S.; Lee, P.D.

2003-01-01

Macroscopic modeling of heat transfer and fluid flow is now routinely used for the prediction of macroscopic defects in castings, while microscopic models are used to investigate the effects of alloy changes on typical microstructures. By combining these two levels of modeling it is possible to simulate the casting process over a wider range of spatial and temporal scales. This paper presents a multiscale model where micromodels for dendrite arm spacing and microporosity are incorporated into a macromodel of heat transfer and in order to predict the as cast microstructure and prevalence of microscopic defects, specifically porosity. The approach is applied to aluminum alloy (L169) investment castings. The models are compared with results obtained by optical image analysis of prepared slices, and X-ray tomography of volume samples from the experiments. Multiscale modeling is shown to provide the designer with a useful tool to improve the properties of the final casting by testing how altering the casting process affects the final microstructure including porosity
The deformation of wax patterns and castings in investment casting technology

Directory of Open Access Journals (Sweden)

A. Herman

2012-01-01

Full Text Available The dimensional accuracy of the final casting of Inconel alloy 738 LC is affected by many aspects. One of them is the choice of method and time of cooling wax model for precision investment casting. The main objective was to study the initial deformation of the complex shape of the casting of the rotor blades. Various approaches have been tested for cooling wax pattern. When wax models are cooling on the air, without clamping in jig for cooling, deviations from the ideal shape of the casting are very noticeable (up to 8 mm and most are in extreme positions of the model. When blade is cooled in fixing jig in water environment, the resulting deviations compared with cooling in air are significantly larger, sometimes up to 10 mm. This itself does not mean that the final shape of the casting is dimensionally more accurate with usage of wax models, which have deviations from the ideal position smaller. Another deformation occurs when shell mould is produced around wax pattern and furthermore deformations emerge while casting of blade is cooling. This paper demonstrates first steps in describing complex process of deformations of Inconel alloy blades produced with investment casting technology by comparing results from thermal imagery, simulations in foundry simulation software ProCAST 2010 and measurements from CNC scanning system Carl Zeiss MC 850. Conclusions are so far not groundbreaking, but it seems deformations of wax pattern and deformations of castings do in some cases cancel each other by having opposite directions. Describing entirely whole process of deformations will help increase precision of blade castings so that models at the beginning and blades in the end are the same.
Clean Metal Casting; FINAL

International Nuclear Information System (INIS)

Makhlouf M. Makhlouf; Diran Apelian

2002-01-01

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
Influence of the cordierite lining on the lost foam casting process

Directory of Open Access Journals (Sweden)

Trumbulović Ljiljana

2003-01-01

Full Text Available This paper discuss the influence of the refractory cordierite lining on the structure and mechanical properties of Al-Si and Al-Cu casings obtained from the Lost foam casting process. So far there has not been any report of the research on cordierite lining in the literature and moreover the cordierite ceramics have never been used in foundries. In the light of these facts this paper investigates the possibility of using cordierite for manufacturing evaporable model refractory linings. Our results indicate that the application of cordierite ceramics is comparable to talc-based refractory linings in both Al-Cu and Al-Si castings, while cordierites are favorable in Al-Cu case due to their higher melting temperature.
Fabrication of sacrificial anode cathodic protection through casting method

International Nuclear Information System (INIS)

Mohd Sharif Sattar; Muhamad Daud; Siti Radiah Mohd Kamarudin; Azali Muhamad; Zaiton Selamat; Rusni Rejab

2007-01-01

Aluminum is one of the few metals that can be cast by all of the processes used in casting metals. These processes consist of die casting, permanent mold casting, sand casting (green sand and dry sand), plaster casting, investment casting, and continuous casting. Other processes such as lost foam, squeeze casting, and hot isostatic pressing are also used. Permanent mold casting method was selected in which used for fabricating of sacrificial anode cathodic protection. This product was ground for surface finished and fabricated in the cylindrical form and reinforced with carbon steel at a center of the anode. (Author)
Thin film processes

CERN Document Server

Vossen, John L

1978-01-01

Remarkable advances have been made in recent years in the science and technology of thin film processes for deposition and etching. It is the purpose of this book to bring together tutorial reviews of selected filmdeposition and etching processes from a process viewpoint. Emphasis is placed on the practical use of the processes to provide working guidelines for their implementation, a guide to the literature, and an overview of each process.
Fatigue Resistance of GX12CrMoVNbN9-1 Cast Steel after Ageing Process

Directory of Open Access Journals (Sweden)

Stanisław MROZIŃSKI

2014-12-01

Full Text Available In the present paper, low cycle fatigue behaviour of GX12CrMoVNbN9-1 (GP91 cast steel is presented. Fatigue tests were performed under isothermal conditions at room temperature and at 550 and 600oC, on five levels of total strain amplitude value ɛac = 0.25÷0.60%. The cast steel subject to investigation was in the as-received condition (after heat treatment and after 8000 hours of ageing at the temperature of 600oC. Performed research has shown an insignificant influence of the ageing process on mechanical properties of GP91 cast steel, determined with the static test of tension. Analysis of the performed tests has proved that GP91 cast steel in the as-received condition and after ageing process was characterized by strong cyclic softening without a clear period of stabilization of the hysteresis loop parameters. The fatigue lifetime curves at each temperature were obtained based on Basquin and Coffin – Manson equations. The process of ageing of GP91 cast steel contributed to a decrease in its fatigue life Nf from a few to a few dozen percent, and the level of fatigue life was dependent on the value of strain amplitude ɛac. It has also been stated that the fatigue life Nf of GP91 cast steel is determined by its plastic properties, and the degree of changes in fatigue life Nf was dependent not only on the temperature of testing, but also on the value of strain amplitude ɛac. DOI: http://dx.doi.org/10.5755/j01.ms.20.4.6077
Production of A356 aluminum alloy wheels by thixo-forging combined with a low superheat casting process

Directory of Open Access Journals (Sweden)

Wang Shuncheng

2013-09-01

Full Text Available The A356 aluminum alloy wheels were produced by thixo-forging combined with a low superheat casting process. The as-cast microstructure, microstructure evolution during reheating and the mechanical properties of thixo-forged wheels made from the A356 aluminum alloy were studied. The results show that the A356 aluminum alloy round billet with fine, uniform and non-dendritic grains can be obtained when the melt is cast at 635 篊. When the round billet is reheated at 600 篊 for 60 min, the non-dendritic grains are changed into spherical ones and the round billet can be easily thixo-forged into wheels. The tensile strength, yield strength and elongation of the thixo-forged wheels with T6 heat treatment are 327.6 MPa, 228.3 MPa and 7.8%, respectively, which are higher than those of a cast wheel. It is suggested that the thixo-forging combined with the low superheat casting process is an effective technique to produce aluminum alloy wheels with high mechanical properties.
Process for forming thin film, heat treatment process of thin film sheet, and heat treatment apparatus therefor

International Nuclear Information System (INIS)

Watanabe, S.

1984-01-01

The invention provides a process for forming a magnetic thin film on a base film, a heat treatment process of a thin film sheet consisting of the base film and the magnetic thin film, and an apparatus for performing heat treatment of the thin film sheet. Tension applied to the thin film sheet is substantially equal to that applied to the base film when the magnetic thin film is formed thereon. Then, the thin film sheet is treated with heat. The thin film sheet is heated with a given temperature gradient to a reactive temperature at which heat shrinkage occurs, while the tension is being applied thereto. Thereafter, the thin film sheet to which the tension is still applied is cooled with substantially the same temperature gradient as applied in heating. The heat treatment apparatus has a film driving unit including a supply reel, a take-up reel, a drive source and guide rollers; a heating unit including heating plates, heater blocks and a temperature controller for heating the sheet to the reactive temperature; and a heat insulating unit including a thermostat and another temperature controller for maintaining the sheet at the nonreactive temperature which is slightly lower than the reactive temperature
HFIR Fuel Casting Support

Energy Technology Data Exchange (ETDEWEB)

Imhoff, Seth D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Gibbs, Paul Jacob [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Solis, Eunice Martinez [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-09-28

Process exploration for fuel production for the High Flux Isotope Reactor (HFIR) using cast LEU-10wt.%Mo as an initial processing step has just begun. This project represents the first trials concerned with casting design and quality. The studies carried out over the course of this year and information contained in this report address the initial mold development to be used as a starting point for future operations. In broad terms, the final billet design is that of a solid rolling blank with an irregular octagonal cross section. The work covered here is a comprehensive view of the initial attempts to produce a sound casting. This report covers the efforts to simulate, predict, cast, inspect, and revise the initial mold design.
Calorimetric analysis of heating and cooling process of nodular cast iron

Directory of Open Access Journals (Sweden)

Bińczyk F.

2007-01-01

Full Text Available The study presents the results of investigations of the thermal effects which take place during heating and cooling of samples of the nodular graphite cast iron taken from the stepped test casting of the wall thicknesses amounting to 5, 10, 15 and 20 mm. For investigations, a differential scanning calorimeter, type Multi HTC S60, was used. During heating, three endothermic effects related with pearlite decomposition, phase transformation α → γ, and carbon dissolution in austenite were observed on a DSC diagram. During cooling, two exothermic effects related with phase transformation γ→ α and pearlite formation were observed to consecutively take place on a DSC diagram. The values of the enthalpy of these processes differ and depend on the initial microstructure of the examined samples. The metallic matrix in 5 mm sample after the process of heating and cooling changes totally in favour of ferrite. The same effect, though less advanced in intensity, takes place in 10 mm sample, while in 15 and 20 mm samples the matrix constitution remains unchanged. The higher is the content of ferrite in samples, the stronger is the endothermic effect of the α → γ transformation and the weaker is the endothermic effect related with carbon dissolution in austenite. The total of the endothermic effects (heating is reduced, while that of the exothermic effects (cooling increases along with the increasing thickness of walls in a stepped test casting, from which samples for the investigations were taken.
The structure of abrasion-resisting castings made of chromium cast iron

Directory of Open Access Journals (Sweden)

D. Kopyciński

2011-01-01

Full Text Available In this study presents the analyse of chrome iron cast structure (as-cast condition which are used in rugged conditions abrasion-percussive and high temperature. While producing the casts of chrome iron major influence has been preserve the structure of technologi cal process parameters. The addition to Fe-C-Cr alloy Ni, Mo or Cu and then proper heat treatment leads to the improvement of functional and mechanical cast qualities. Then it is possible to develop high mechanical properties which are recommended by PN-EN12513. As can it be seen from the above research silicon is an adverse chemical element in this kind of alloy cast iron. However, the reason of cracksappearing in chrome iron casts are phosphorus eutectic microareas. When the compound of Si and P reach the critical point, described inPN-88/H-83144 outdated standard, the microareas might appear.
Characterisation and modelling of defect formation in direct-chill cast AZ80 alloy

Energy Technology Data Exchange (ETDEWEB)

Mackie, D.; Robson, J.D.; Withers, P.J. [School of Materials, University of Manchester, Manchester M13 9PL (United Kingdom); Turski, M. [Magnesium Elektron UK, Rake Lane, Manchester, M27 8BF (United Kingdom)

2015-06-15

Wrought magnesium alloys for demanding structural applications require high quality defect free cast feedstock. The aim of this study was to first identify and characterise typical defects in direct chill cast magnesium–aluminium–zinc (AZ) alloy billet and then use modelling to understand the origins of these defects so they can be prevented. Defects were first located using ultrasonic inspection and were then characterised using X-ray computed tomography (XCT) and serial sectioning, establishing the presence of oxide films and intermetallic particles Al{sub 8}Mn{sub 5} in all defects. A model was developed to predict the flow patterns and growth kinetics of the intermetallic phases during casting, which influence the formation of defects. Simulation of the growth of the intermetallic particles demonstrated that precipitation from the liquid occurs in the mould. The combination of the entrained oxide films and intermetallic particles recirculates in the liquid metal and continues to grow, until large enough to settle, which is predicted to occur at the centre of the mould where the flow is the slowest. Based on these predictions, strategies to reduce the susceptibility to defect formation are suggested. - Highlights: • Casting defects in magnesium direct chill casting have been imaged and characterised in 3-dimensions. • The occurrences of co-located clusters of particles and oxide films have been characterised and explained. • A coupled model has been developed to help interpret the observed trend for defects located towards the centre of billets.
Characterisation and modelling of defect formation in direct-chill cast AZ80 alloy

International Nuclear Information System (INIS)

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

2015-01-01

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

Science.gov (United States)

Moey, Siah Watt; Abdullah, Aminah; Ahmad, Ishak

2014-09-01

A new patent pending process is proposed in this study to produce edible film directly from seaweed (Kappaphycus alvarezii). Seaweed together with other ingredients had been used to produce the film through casting technique. Physical and mechanical tests were performed on the edible film to examine the thickness, colour, transparency, solubility, tensile strength, elongation at break, water permeability rate, oxygen permeability rate and surface morphology. The produced film was transparent, stretchable, sealable and have basic properties for applications in food, pharmaceutical, cosmetic, toiletries and also agricultural industries. Edible film was successfully developed directly from dry seaweed instead of using alginate and carrageenan. The edible film processing method developed in this research was easier and cheaper compared with the method by using alginate and carrageenan.
Low Loss Advanced Metallic Fuel Casting Evaluation

International Nuclear Information System (INIS)

Kim, Kihwan; Ko, Youngmo; Kim, Jonghwan; Song, Hoon; Lee Chanbock

2014-01-01

The fabrication process for SFR fuel is composed of fuel slug casting, loading and fabrication of the fuel rods, and the fabrication of the final fuel assemblies. Fuel slug casting is the dominant source of fuel losses and recycles streams in the fabrication process. Recycle streams include fuel slug reworks, returned scraps, and fuel casting heels, which are a special concern in the counter gravity injection casting process because of the large masses involved. Large recycle and waste streams result in lowering the productivity and the economic efficiency of fuel production. To increase efficiency the fuel losses in the furnace chamber, crucible, and the mold, after casting a considerable amount of fuel alloy in the casting furnace, will be quantitatively evaluated. After evaluation the losses will be identified and minimized. It is expected that this study will contribute to the minimization of fuel losses and the wastes streams in the fabrication process of the fuel slugs. Also through this study the technical readiness level of the metallic fuel fabrication process will be further enhanced. In this study, U-Zr alloy system fuel slugs were fabricated by a gravity casting method. Metallic fuel slugs were successfully fabricated with 19 slugs/batch with diameter of 5mm and length of 300mm. Fuel losses was quantitatively evaluated in casting process for the fuel slugs. Fuel losses of the fuel slugs were so low, 0.1∼1.0%. Injection casting experiments have been performed to reduce the fuel loss and improve the casting method. U-Zr fuel slug having φ5.4-L250mm was soundly fabricated with 0.1% in fuel loss. The fuel losses could be minimized to 0.1%, which showed that casting technology of fuel slugs can be a feasible approach to reach the goal of the fuel losses of 0.1% or less in commercial scale
Optimization of squeeze casting parameters for non symmetrical AC2A aluminium alloy castings through Taguchi method

International Nuclear Information System (INIS)

Senthil, P.; Amirthagadeswaran, K. S.

2012-01-01

This paper reports a research in which an attempt was made to prepare AC2A aluminium alloy castings of a non symmetrical component through squeeze casting process. The primary objective was to investigate the influence of process parameters on mechanical properties of the castings. Experiments were conducted based on orthogonal array suggested in Taguchi's offline quality control concept. The experimental results showed that squeeze pressure, die preheating temperature and compression holding time were the parameters making significant improvement in mechanical properties. The optimal squeeze casting condition was found and mathematical models were also developed for the process
Energy use in selected metal casting facilities - 2003

Energy Technology Data Exchange (ETDEWEB)

Eppich, Robert E. [Eppich Technologies, Syracuse, IN (United States)

2004-05-01

This report represents an energy benchmark for various metal casting processes. It describes process flows and energy use by fuel type and processes for selected casting operations. It also provides recommendations for improving energy efficiency in casting.
Colour Metallography of Cast Iron

Directory of Open Access Journals (Sweden)

Zhou Jiyang

2009-05-01

Full Text Available Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application and combine cast iron technology with some hi-techs (for example, computer technology. Nevertheless, cast iron is a multi-element and multi-phase alloy and has complex and variety of structures and still has great development potential in structure and property. For further studying and developing cast iron, theoretical research work is important promise, and the study on solidification process and control mechanism of graphite morphology is fundamental for improving property of cast iron and developing new type of cast iron.Metallography of cast iron normally includes two sections: liquid phase transformation and solid phase transformation. The book, Colour Metallography of Cast Iron , uses colour metallography technique to study solidification structures of cast irons: graphite, carbides, austenite and eutectics; and focuses on solidification processes. With progress of modern solidification theory, the control of material solidification process becomes important measure for improving traditionalmaterials and developing new materials. Solidification structure not only influences mechanical and physical properties of cast iron, but also affects its internal quality. The book uses a large amount of colour photos to describe the formation of solidification structures and their relations. Crystallization phenomena, which cannot be displayed with traditional metallography, are presented and more phase transformation information is obtained from these colour

Development of Cast Alumina-forming Austenitic Stainless Steel Alloys for use in High Temperature Process Environments

Energy Technology Data Exchange (ETDEWEB)

Muralidharan, Govindarajan [ORNL; Yamamoto, Yukinori [ORNL; Brady, Michael P [ORNL; Pint, Bruce A [ORNL; Pankiw, Roman [Duraloy Technologies Inc; Voke, Don [Duraloy Technologies Inc

2015-01-01

There is significant interest in the development of alumina-forming, creep resistant alloys for use in various industrial process environments. It is expected that these alloys can be fabricated into components for use in these environments through centrifugal casting and welding. Based on the successful earlier studies on the development of wrought versions of Alumina-Forming Austenitic (AFA) alloys, new alloy compositions have been developed for cast products. These alloys achieve good high-temperature oxidation resistance due to the formation of protective Al₂O₃ scales while multiple second-phase precipitation strengthening contributes to excellent creep resistance. This work will summarize the results on the development and properties of a centrifugally cast AFA alloy. This paper highlights the strength, oxidation resistance in air and water vapor containing environments, and creep properties in the as-cast condition over the temperature range of 750°C to 900°C in a centrifugally cast heat. Preliminary results for a laboratory cast AFA composition with good oxidation resistance at 1100°C are also presented.
Precipitation processes in DC-cast AlMn(Fe,Si) alloys

International Nuclear Information System (INIS)

Voeroes, G.; Kovacs, I.

1990-01-01

The precipitation processes in DC cast Al-Mn alloys were investigated by electrical resistivity measurements. It was obtained that the addition of Fe or Fe and Si influences basically the precipitation of Mn. In pure Al-Mn alloys a phase transition like behaviour was observed at about 550 degC, which can be related to the formation of two different precipitate particles below and above this temperature
Direct Cast U-6Nb – 2017 Progress on Cylindrical Castings

Energy Technology Data Exchange (ETDEWEB)

Aikin, Jr., Robert M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-10-04

This report describes work to further develop a sound technical basis and best practices for mold design and process parameters for the Direct Casting of U-6wt%Nb components. One major challenge to the production of U-6Nb components is the propensity for niobium segregation during casting and solidification. This is especially true for cylindrical castings where the vertical side walls allow flotation of Nb resulting in severe inverse macrosegregation. In this work, a small (120 mm diameter by 180 mm tall) and large cylinder (250 mm diameter by 310 mm tall) are examined with a focus on reducing, or eliminating, niobium segregation. It is demonstrated that counter gravity casting (top-to-bottom solidification) can be used to minimize segregation in the small cylinder. Attempts to counter gravity cast the large cylinder were unsuccessful, in large part due to size limitations of the current furnace. A path forward for casting of the large cylinders is discussed.
Properties of tungsten films prepared by magnetron sputtering

International Nuclear Information System (INIS)

Ahn, K.Y.; Ting, C.Y.; Brodsky, S.B.; Fryer, P.M.; Davari, B.; Angillelo, J.; Herd, S.R.; Licata, T.

1986-01-01

High-rate magnetron sputtering is a relatively simple process to produce tungsten films with good electrical and mechanical properties, and it offers good uniformity, reproducibility, process flexibility, and high throughput. The purity of the sputtered films is affected by the target purity (cold-pressed 99.95%, chemical vapor deposited 99.99% and cast 99.999%), base pressure, deposition rate, and substrate bias. Typical resistivity in films of 2000 to 3000A thickness deposited on Si, poly-Si, and SiO/sub 2/ ranges from 10 to 12 μΩ-cm, and this may be compared with 6 and 11 μΩ-cm by high-temperature evaporation and chemical vapor deposition, respectively. The presence of biaxial stress caused by substrate scanning was determined by x-ray technique. The sputtered films exhibit high compressive stress when deposited at low Ar pressure. It decreases with increasing pressure, and eventually changes sign to become tensile, and increases further with increasing pressure. Effects of processing parameters on films properties, and a comparison of film properties prepared by evaporation and chemical vapor deposition are discussed
A process chain for integrating piezoelectric transducers into aluminum die castings to generate smart lightweight structures

Directory of Open Access Journals (Sweden)

Stefan Stein

Full Text Available The application of piezoelectric transducers to structural body parts of machines or vehicles enables the combination of passive mechanical components with sensor and actuator functions in one single structure. According to Herold et al. [1] and Staeves [2] this approach indicates significant potential regarding smart lightweight construction. To obtain the highest yield, the piezoelectric transducers need to be integrated into the flux of forces (load path of load bearing structures. Application in a downstream process reduces yield and process efficiency during manufacturing and operation, due to the necessity of a subsequent process step of sensor/actuator application. The die casting process offers the possibility for integration of piezoelectric transducers into metal structures. Aluminum castings are particularly favorable due to their high quality and feasibility for high unit production at low cost (Brunhuber [3], Nogowizin [4]. Such molded aluminum parts with integrated piezoelectric transducers enable functions like active vibration damping, structural health monitoring or energy harvesting resulting in significant possibilities of weight reduction, which is an increasingly important driving force of automotive and aerospace industry (Klein [5], Siebenpfeiffer [6] due to increasingly stringent environmental protection laws. In the scope of those developments, this paper focuses on the entire process chain enabling the generation of lightweight metal structures with sensor and actuator function, starting from the manufacturing of piezoelectric modules over electrical and mechanical bonding to the integration of such modules into aluminum (Al matrices by die casting. To achieve this challenging goal, piezoceramic sensors/actuator modules, so-called LTCC/PZT modules (LPM were developed, since ceramic based piezoelectric modules are more likely to withstand the thermal stress of about 700 °C introduced by the casting process (Flössel et
Simulation of the injection casting of metallic fuels

International Nuclear Information System (INIS)

Nakagawa, Tomokazu; Ogata, Takanari; Tokiwai, Moriyasu.

1989-01-01

For the fabrication of metallic fuel pins, injection casting is a preferable process because the simplicity of the process is suitable for remote operation. In this process, the molten metal in the crucible is injected into evacuated molds (suspended above the crucible) by pressurizing the casting furnace. Argonne National Laboratory has already adopted this process in the Integral Fast Reactor program. To obtain fuel pins with good quality, the casting parameters, such as the molten metal temperature, the magnitude of the pressure applied, the pressurizing rate, the cooling time, etc., must be optimized. Otherwise, bad-quality castings (short castings, rough surfaces, shrinkage cavities, mold fracture) may result. Therefore, it is very important in designing the casting equipment and optimizing the operation conditions to be able to predict the fluid and thermal behavior of the castings. This paper describes methods to simulate the heat and mass transfer in the molds and molten metallic fuel during injection casting. The results obtained by simulation are compared with experimental ones. Also, appropriate casting conditions for the uranium-plutonium-zirconium alloy are discussed based on the simulated results
Advanced Casting Technology

Science.gov (United States)

1982-08-01

Anodic Films for the Protection of Magnesium Alloys". G.R. Kotler, D.L. Hawke and E.N. Agua . Proc. International Magnesium Association, Montreal, May...HCF testing, impellers were bench tested to assess the in situ fatigue capabilities of 250-C28 impeller airfoils. In this testing, the airfoils...64 at 204oC (400oF), 13- T to a> o >-, o r- i—l CD -*—• Cast Wrought TE-2222 Ficure 11. In situ HCF results for Ti-64 Model 250
Quality Assessment of Film Processing Chemicals in Dentistry

International Nuclear Information System (INIS)

Han, Mi Ra; Kang, Byung Chul

1999-01-01

The purpose of this study was to compare the qualities of the four different processing chemicals (solutions). With EP 21 films (Ektaspeed plus film, Kodak Co., USA), nine unexposed and nine exposed films of a step wedge were processed utilizing automatic film processor (XR 24, Durr Co., Germany) for 5 days. During 5 days, the total number of processed films including out-patient's intraoral films were about 400-500 for each brand. Base plus fog density, film density, contrast of processed films were measured with densitometer (model 07-443 digital densitometer, Victoreen Co., USA). These measurements were analyzed for comparison. The results were as follows,1. For the base plus fog density, there was significant difference among the four chemicals (p<0.05). The sequence of the base plus fog densities was in ascending order by Kodak, X-dol 90, Agfa and Konica. 2. For the film density, all chemicals showed useful range of photographic densities (0.25-2.5). The sequence of the film densities was in ascending order by Kodak, X-dol 90, Konica and Agfa. But there was no statistically significant difference of film density between X-dol and Kodak (p<0.05). 3. The sequence of the contrasts was in ascending order by Konica, X-dol 90, Kodak and Agfa. But there was no statistically significant difference of contrast between X-dol and Konica (p<0.05). These results indicated that the four processing chemicals had the clinically useful film density and contrast, but only Kodak processing chemical had useful base plus fog density.
Triple-component nanocomposite films prepared using a casting method: Its potential in drug delivery

Directory of Open Access Journals (Sweden)

Sadia Gilani

2018-04-01

Full Text Available The purpose of this study was to fabricate a triple-component nanocomposite system consisting of chitosan, polyethylene glycol (PEG, and drug for assessing the application of chitosan–PEG nanocomposites in drug delivery and also to assess the effect of different molecular weights of PEG on nanocomposite characteristics. The casting/solvent evaporation method was used to prepare chitosan–PEG nanocomposite films incorporating piroxicam-β-cyclodextrin. In order to characterize the morphology and structure of nanocomposites, X-ray diffraction technique, scanning electron microscopy, thermogravimetric analysis, and Fourier transmission infrared spectroscopy were used. Drug content uniformity test, swelling studies, water content, erosion studies, dissolution studies, and anti-inflammatory activity were also performed. The permeation studies across rat skin were also performed on nanocomposite films using Franz diffusion cell. The release behavior of films was found to be sensitive to pH and ionic strength of release medium. The maximum swelling ratio and water content was found in HCl buffer pH 1.2 as compared to acetate buffer of pH 4.5 and phosphate buffer pH 7.4. The release rate constants obtained from kinetic modeling and flux values of ex vivo permeation studies showed that release of piroxicam-β-cyclodextrin increased with an increase in concentration of PEG. The formulation F10 containing 75% concentration of PEG showed the highest swelling ratio (3.42±0.02 in HCl buffer pH 1.2, water content (47.89±1.53% in HCl buffer pH 1.2, maximum cumulative drug permeation through rat skin (2405.15±10.97 μg/cm2 in phosphate buffer pH 7.4, and in vitro drug release (35.51±0.26% in sequential pH change mediums, and showed a significantly (p<0.0001 higher anti-inflammatory effect (0.4 cm. It can be concluded from the results that film composition had a particular impact on drug release properties. The different molecular weights of PEG have a
HANFORD CONTAINERIZED CAST STONE FACILITY TASK 1 PROCESS TESTING & DEVELOPMENT FINAL TEST REPORT

Energy Technology Data Exchange (ETDEWEB)

LOCKREM, L L

2005-07-13

Laboratory testing and technical evaluation activities on Containerized Cast Stone (CCS) were conducted under the Scope of Work (SOW) contained in CH2M HILL Hanford Group, Inc. (CHG) Contract No. 18548 (CHG 2003a). This report presents the results of testing and demonstration activities discussed in SOW Section 3.1, Task I--''Process Development Testing'', and described in greater detail in the ''Containerized Grout--Phase I Testing and Demonstration Plan'' (CHG, 2003b). CHG (2003b) divided the CCS testing and evaluation activities into six categories, as follows: (1) A short set of tests with simulant to select a preferred dry reagent formulation (DRF), determine allowable liquid addition levels, and confirm the Part 2 test matrix. (2) Waste form performance testing on cast stone made from the preferred DRF and a backup DRF, as selected in Part I, and using low activity waste (LAW) simulant. (3) Waste form performance testing on cast stone made from the preferred DRF using radioactive LAW. (4) Waste form validation testing on a selected nominal cast stone formulation using the preferred DRF and LAW simulant. (5) Engineering evaluations of explosive/toxic gas evolution, including hydrogen, from the cast stone product. (6) Technetium ''getter'' testing with cast stone made with LAW simulant and with radioactive LAW. In addition, nitrate leaching observations were drawn from nitrate leachability data obtained in the course of the Parts 2 and 3 waste form performance testing. The nitrate leachability index results are presented along with other data from the applicable activity categories.
Improvement of Artistic Cast Production System

Directory of Open Access Journals (Sweden)

Władysiak R.

2017-09-01

Full Text Available The paper presents the technology and organization of the artistic cast production. On the basis of the actual cast production system, the manufacturing process was shown, in particular sand–piece moulding, which is a very important process and a time-consuming part of the entire manufacture of the casts. The current state of the production process as well as the organization of the work and production technology were analysed with the use of methods and techniques of production improvement, the Lean Manufacturing concept and computer systems. The results of the analysis and studies were shown with use of schemes and graphs of the layout of the production resources, a flow chart of the production process, value stream mapping, and a costs table for the production and modernization of the moulding stage. The work has shown that there are possibilities to improve the artistic cast production system. This improvement leads to increased productivity, lower production costs of artistic casts and increased competitiveness of the foundry.
Applying a Numerical Model of the Continuous Steel Casting Process to Control the Length of the Liquid Core in the Strand

Directory of Open Access Journals (Sweden)

Miłkowska-Piszczek K.

2015-04-01

Full Text Available This paper presents development and the application of a numerical model of the continuous steel casting process to optimise the strand solidification area. The design of the numerical model of the steel continuous casting process was presented and which was developed based on the actual dimensions of the slab continuous casting machine in ArcelorMittal Poland Unit in Kraków. The S235 steel grade and the cast strand format of 220×1280 mm were selected for the tests. Three strand casting speeds were analysed: 0.6, 0.8 and 1 m min-1. An algorithm was presented, allowing the calculation of the heat transfer coefficient values for the secondary cooling zone. In order to verify the results of numerical simulations, additional temperature measurements of the strand surface within the secondary cooling chamber were made. The ProCAST software was used to construct the numerical model of continuous casting of steel.
The taper of cast post preparation measured using innovative image processing technique

Directory of Open Access Journals (Sweden)

Al Hyiasat Ahmad S

2010-08-01

Full Text Available Abstract 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 using polyvinyl siloxan putty/wash technique. Digital camera with a 10' high quality lens was used for capturing two digital images for each impression; one in the Facio-Lingual (FL and the other in the Mesio-Distal (MD directions. Automated image processing program was developed to measure the degree of canal taper. Data were analyzed using Statistical Package for Social Sciences software and One way Analysis of Variance. Results Eighty four dies for cast posts were collected: 16 for each maxillary anterior teeth subgroup, and 18 for each maxillary and mandibular premolar subgroup. Mean of total taper for all preparations was 10.7 degree. There were no statistical differences among the total taper of all groups (P = .256 or between the MD and FL taper for each subgroup. Mean FL taper for the maxillary first premolars was lower significantly (P = .003 than the maxillary FL taper of the second premolars. FL taper was higher than the MD taper in all teeth except the maxillary first premolars. Conclusions Taper produced did not reflect the differences among the anatomy of teeth. While this technique deemed satisfactory in the maxillary anterior teeth, the same could not be said for the maxillary first premolars. Careful attention to the root anatomy is mandatory.
Chemical casting of high-Tc superconducting BiSCCO

International Nuclear Information System (INIS)

Toth, L.E.; Das, B.N.; Rayne, R.J.; Bender, B.A.; Lechter, W.L.; Hoff, H.A.; Osofsky, M.S.; Soulen, R.J. Jr.

1989-01-01

BiSCCO has been successfully cast into a number of useful shapes. This casting process differs significantly from traditional casting in that the process includes a change in the oxygen content of the melt. A heat treatment is required to restore the original chemistry, properly form the BiSCCO crystal structure and develop the superconducting properties. This paper emphasizes the microstructures of as-cast and heat treated BiSCCO. Casting causes considerable grain alignment of the BiSCCO platelets. The platelets align preferentially along the thermal gradients which exist during the solidification process
Synthesis and structural evaluation of freeze-cast porous alumina

Energy Technology Data Exchange (ETDEWEB)

Souza, Douglas F., E-mail: souzadf@outlook.com [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Nunes, Eduardo H.M., E-mail: eduardohmn@gmail.com [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Pimenta, Daiana S.; Vasconcelos, Daniela C.L. [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil); Nascimento, Jailton F.; Grava, Wilson [Petrobras/CENPES, Avenida Horácio Macedo 950, Cidade Universitária, Ilha do Fundão, Rio de Janeiro, RJ CEP:21941-915 (Brazil); Houmard, Manuel [Department of Materials Engineering and Civil Construction, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 1, sala 3304 (Brazil); Vasconcelos, Wander L., E-mail: wlv@demet.ufmg.br [Department of Metallurgical and Materials Engineering, Federal University of Minas Gerais — UFMG, Avenida Presidente Antônio Carlos, 6627, Campus UFMG, Belo Horizonte, MG CEP: 31270-901, Escola de Engenharia, bloco 2, sala 2230 (Brazil)

2014-10-15

In this work we fabricated alumina samples by the freeze-casting technique using tert-butanol as the solvent. The prepared materials were examined by scanning electron microscopy and X-ray microtomography. Next, they were coated with sol–gel silica films by dip-coating. Permeability tests were carried out in order to assess the permeation behavior of the materials processed in this study. We observed that the sintering time and alumina loading showed a remarkable effect on both the structural properties and flexural strength of the freeze-cast samples. Nitrogen adsorption tests revealed that the silica prepared in this study exhibited a microporous structure. It was observed that the presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance by about one order of magnitude. Because of the similar kinetic diameters of nitrogen and carbon dioxide, the CO{sub 2}/N{sub 2} system showed a separation efficiency that was lower than that observed for the He/CO{sub 2} and He/N{sub 2} systems. We noticed that increasing the feed pressure improved the separation capacity of the obtained materials. - Highlights: • Porous alumina samples obtained by the freeze-casting technique • Microporous silica coating prepared by a simple sol–gel dip-coating methodology • Samples examined by SEM, μ-CT, and nitrogen sorption tests • Mechanical tests were carried out in the freeze-cast samples. • The presence of silica coatings on the alumina surface decreased the CO{sub 2} permeance.
Multi-layers castings

Directory of Open Access Journals (Sweden)

J. Szajnar

2010-01-01

Full Text Available In paper is presented the possibility of making of multi-layers cast steel castings in result of connection of casting and welding coating technologies. First layer was composite surface layer on the basis of Fe-Cr-C alloy, which was put directly in founding process of cast carbon steel 200–450 with use of preparation of mould cavity method. Second layer were padding welds, which were put with use of TIG – Tungsten Inert Gas surfacing by welding technology with filler on Ni matrix, Ni and Co matrix with wolfram carbides WC and on the basis on Fe-Cr-C alloy, which has the same chemical composition with alloy, which was used for making of composite surface layer. Usability for industrial applications of surface layers of castings were estimated by criterion of hardness and abrasive wear resistance of type metal-mineral.
Solvent vapor annealing in the molecular regime drastically improves carrier transport in small-molecule thin-film transistors

KAUST Repository

Khan, Hadayat Ullah

2013-04-10

We demonstrate a new way to investigate and control the solvent vapor annealing of solution-cast organic semiconductor thin films. Solvent vapor annealing of spin-cast films of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pn) is investigated in situ using quartz crystal microbalance with dissipation (QCM-D) capability, allowing us to monitor both solvent mass uptake and changes in the mechanical rigidity of the film. Using time-resolved grazing incidence wide angle X-ray scattering (GIWAXS) and complementary static atomic force microscopy (AFM), we demonstrate that solvent vapor annealing in the molecular regime can cause significant performance improvements in organic thin film transistors (OTFTs), whereas allowing the solvent to percolate and form a liquid phase results in catastrophic reorganization and dewetting of the film, making the process counterproductive. Using these lessons we devise processing conditions which prevent percolation of the adsorbed solvent vapor molecules for extended periods, thus extending the benefits of solvent vapor annealing and improving carrier mobility by nearly two orders of magnitude. Ultimately, it is demonstrated that QCM-D is a very powerful sensor of the state of the adsorbed solvent as well as the thin film, thus making it suitable for process development as well as in-line process monitoring both in laboratory and in future manufacturing settings. © 2013 American Chemical Society.
Solvent vapor annealing in the molecular regime drastically improves carrier transport in small-molecule thin-film transistors

KAUST Repository

Khan, Hadayat Ullah; Li, Ruipeng; Ren, Yi; Chen, Long; Payne, Marcia M.; Bhansali, Unnat Sampatraj; Smilgies, Detlef Matthias; Anthony, John Edward; Amassian, Aram

2013-01-01

We demonstrate a new way to investigate and control the solvent vapor annealing of solution-cast organic semiconductor thin films. Solvent vapor annealing of spin-cast films of 6,13-bis(triisopropylsilylethynyl) pentacene (TIPS-Pn) is investigated in situ using quartz crystal microbalance with dissipation (QCM-D) capability, allowing us to monitor both solvent mass uptake and changes in the mechanical rigidity of the film. Using time-resolved grazing incidence wide angle X-ray scattering (GIWAXS) and complementary static atomic force microscopy (AFM), we demonstrate that solvent vapor annealing in the molecular regime can cause significant performance improvements in organic thin film transistors (OTFTs), whereas allowing the solvent to percolate and form a liquid phase results in catastrophic reorganization and dewetting of the film, making the process counterproductive. Using these lessons we devise processing conditions which prevent percolation of the adsorbed solvent vapor molecules for extended periods, thus extending the benefits of solvent vapor annealing and improving carrier mobility by nearly two orders of magnitude. Ultimately, it is demonstrated that QCM-D is a very powerful sensor of the state of the adsorbed solvent as well as the thin film, thus making it suitable for process development as well as in-line process monitoring both in laboratory and in future manufacturing settings. © 2013 American Chemical Society.
Effects of process variables on the properties of YBa2Cu3O(7-x) ceramics formed by investment casting

Science.gov (United States)

Hooker, M. W.; Taylor, T. D.; Leigh, H. D.; Wise, S. A.; Buckley, J. D.; Vasquez, P.; Buck, G. M.; Hicks, L. P.

1993-01-01

An investment casting process has been developed to produce net-shape, superconducting ceramics. In this work, a factorial experiment was performed to determine the critical process parameters for producing cast YBa2Cu3O7 ceramics with optimum properties. An analysis of variance procedure indicated that the key variables in casting superconductive ceramics are the particle size distribution and sintering temperature. Additionally, the interactions between the sintering temperature and the other process parameters (e.g., particle size distribution and the use of silver dopants) were also found to influence the density, porosity, and critical current density of the fired ceramics.
Anodization of cast aluminium alloys produced by different casting methods

Directory of Open Access Journals (Sweden)

K. Labisz

2008-08-01

Full Text Available In this paper the usability of two casting methods, of sand and high pressure cast for the anodization of AlSi12 and AlSi9Cu3 aluminium cast alloys was investigated. With defined anodization parameters like electrolyte composition and temperature, current type and value a anodic alumina surface layer was produced. The quality, size and properties of the anodic layer was investigated after the anodization of the chosen aluminium cast alloys. The Alumina layer was observed used light microscope, also the mechanical properties were measured as well the abrasive wear test was made with using ABR-8251 equipment. The researches included analyze of the influence of chemical composition, geometry and roughness of anodic layer obtained on aluminum casts. Conducted investigations shows the areas of later researches, especially in the direction of the possible, next optimization anodization process of aluminum casting alloys, for example in the range of raising resistance on corrosion to achieve a suitable anodic surface layer on elements for increasing applications in the aggressive environment for example as materials on working building constructions, elements in electronics and construction parts in air and automotive industry.

Babbitt Casting and Babbitt Spraying Processes Case Study

OpenAIRE

M. Jalali Azizpour; S.Norouzi H. Mohammadi Majd

2011-01-01

In this paper, the babbitting of a bearing in boiler feed pump of an electromotor has been studied. These bearings have an important role in reducing the shut down times in the pumps, compressors and turbines. The most conventional method in babbitting is casting as a melting method. The comparison between thermal spray and casting methods in babbitting shows that the thermal spraying babbitt layer has better performance and tribological behavior. The metallurgical and tribological analysis s...
A process chain for integrating piezoelectric transducers into aluminum die castings to generate smart lightweight structures

Science.gov (United States)

Stein, Stefan; Wedler, Jonathan; Rhein, Sebastian; Schmidt, Michael; Körner, Carolin; Michaelis, Alexander; Gebhardt, Sylvia

The application of piezoelectric transducers to structural body parts of machines or vehicles enables the combination of passive mechanical components with sensor and actuator functions in one single structure. According to Herold et al. [1] and Staeves [2] this approach indicates significant potential regarding smart lightweight construction. To obtain the highest yield, the piezoelectric transducers need to be integrated into the flux of forces (load path) of load bearing structures. Application in a downstream process reduces yield and process efficiency during manufacturing and operation, due to the necessity of a subsequent process step of sensor/actuator application. The die casting process offers the possibility for integration of piezoelectric transducers into metal structures. Aluminum castings are particularly favorable due to their high quality and feasibility for high unit production at low cost (Brunhuber [3], Nogowizin [4]). Such molded aluminum parts with integrated piezoelectric transducers enable functions like active vibration damping, structural health monitoring or energy harvesting resulting in significant possibilities of weight reduction, which is an increasingly important driving force of automotive and aerospace industry (Klein [5], Siebenpfeiffer [6]) due to increasingly stringent environmental protection laws. In the scope of those developments, this paper focuses on the entire process chain enabling the generation of lightweight metal structures with sensor and actuator function, starting from the manufacturing of piezoelectric modules over electrical and mechanical bonding to the integration of such modules into aluminum (Al) matrices by die casting. To achieve this challenging goal, piezoceramic sensors/actuator modules, so-called LTCC/PZT modules (LPM) were developed, since ceramic based piezoelectric modules are more likely to withstand the thermal stress of about 700 °C introduced by the casting process (Flössel et al., [7]). The
Processing of thin SU-8 films

International Nuclear Information System (INIS)

Keller, Stephan; Blagoi, Gabriela; Lillemose, Michael; Haefliger, Daniel; Boisen, Anja

2008-01-01

This paper summarizes the results of the process optimization for SU-8 films with thicknesses ≤5 µm. The influence of soft-bake conditions, exposure dose and post-exposure-bake parameters on residual film stress, structural stability and lithographic resolution was investigated. Conventionally, the SU-8 is soft-baked after spin coating to remove the solvent. After the exposure, a post-exposure bake at a high temperature T PEB ≥ 90 °C is required to cross-link the resist. However, for thin SU-8 films this often results in cracking or delamination due to residual film stress. The approach of the process optimization is to keep a considerable amount of the solvent in the SU-8 before exposure to facilitate photo-acid diffusion and to increase the mobility of the monomers. The experiments demonstrate that a replacement of the soft-bake by a short solvent evaporation time at ambient temperature allows cross-linking of the thin SU-8 films even at a low T PEB = 50 °C. Fourier-transform infrared spectroscopy is used to confirm the increased cross-linking density. The low thermal stress due to the reduced T PEB and the improved structural stability result in crack-free structures and solve the issue of delamination. The knowledge of the influence of different processing parameters on the responses allows the design of optimized processes for thin SU-8 films depending on the specific application
Thin-Film Material Science and Processing | Materials Science | NREL

Science.gov (United States)

Thin-Film Material Science and Processing Thin-Film Material Science and Processing Photo of a , a prime example of this research is thin-film photovoltaics (PV). Thin films are important because cadmium telluride thin film, showing from top to bottom: glass, transparent conducting oxide (thin layer
75 FR 8114 - In the Matter of Certain Cast Steel Railway Wheels, Processes for Manufacturing or Relating to...

Science.gov (United States)

2010-02-23

... INTERNATIONAL TRADE COMMISSION [Inv. No. 337-TA-655] In the Matter of Certain Cast Steel Railway Wheels, Processes for Manufacturing or Relating to Same and Certain Products Containing Same ; Issuance... to cast steel railway wheels and products containing same manufactured by or for Respondents using...
Microstructure and mechanical properties of AM50 alloy according to thickness and forming condition of the products by a high pressure die-casting process

Energy Technology Data Exchange (ETDEWEB)

Park, Joon Hong [Dong-A University, Busan (Korea, Republic of); Kang, Chung Gil [Pusan National University, Busan (Korea, Republic of)

2013-10-15

In recent years, Magnesium (Mg) and its alloys have become a center of special interest in the automotive industry. Due to their high specific mechanical properties, they offer a significant weight saving potential in modern vehicle constructions. Most Mg alloys show very good machinability and processability, and even the most complicated die casting parts can be easily produced. The die casting process is a fast production method capable of a high degree of automation for which certain Mg alloys are ideally suited. Although Mg alloys are fulfilling the demands for low specific weight materials with excellent machining and casting abilities, they are still not used in die casting process to the same extent as the competing material aluminum. One of the reasons is that effects of various forming variables for die casting process is not closely examined from the viewpoint of die design. In this study, step die and flowability tests for AM50 were performed by die casting process according to various combination of casting pressure and plunger velocity. Microstructure, Vickers hardness and tensile tests were examined and performed for each specimen to verify effects of forming conditions.
Comparison between two rheocasting processes of damper cooling tube method and low superheat casting

Directory of Open Access Journals (Sweden)

Zhang Xiaoli

2014-09-01

Full Text Available To produce a high quality semisolid slurry that consists of fine primary particles uniformly suspended in the liquid matrix for rheoforming, chemical refining and electromagnetic or mechanical stirring are the two methods commonly used. But these two methods either contaminate the melt or incur high cost. In this study, the damper cooling tube (DCT method was designed to prepare semisolid slurry of A356 aluminum alloy, and was compared with the low superheat casting (LSC method - a conventional process used to produce casting slab with equiaxed dendrite microstructure for thixoforming route. A series of comparative experiments were performed at the pouring temperatures of 650 °C, 638 °C and 622 °C. Metallographic observations of the casting samples were carried out using an optical electron microscope with image analysis software. Results show that the microstructure of semisolid slurry produced by the DCT process consists of spherical primary α-Al grains, while equiaxed grains microstructure is found in the LSC process. The lower the pouring temperature, the smaller the grain size and the rounder the grain morphology in both methods. The copious nucleation, which could be generated in the DCT, owing to the cooling and stirring effect, is the key to producing high quality semisolid slurry. DCT method could produce rounder and smaller α-Al grains, which are suitable for semisolid processing; and the equivalent grain size is no more than 60 μm when the pouring temperature is 622 °C.
Enhancement of Efficiency and Reduction of Grid Thickness Variation on Casting Process with Lean Six Sigma Method

Science.gov (United States)

Witantyo; Setyawan, David

2018-03-01

In a lead acid battery industry, grid casting is a process that has high defect and thickness variation level. DMAIC (Define-Measure-Analyse-Improve-Control) method and its tools will be used to improve the casting process. In the Define stage, it is used project charter and SIPOC (Supplier Input Process Output Customer) method to map the existent problem. In the Measure stage, it is conducted a data retrieval related to the types of defect and the amount of it, also the grid thickness variation that happened. And then the retrieved data is processed and analyzed by using 5 Why’s and FMEA method. In the Analyze stage, it is conducted a grid observation that experience fragile and crack type of defect by using microscope showing the amount of oxide Pb inclusion in the grid. Analysis that is used in grid casting process shows the difference of temperature that is too high between the metal fluid and mold temperature, also the corking process that doesn’t have standard. The Improve stage is conducted a fixing process which generates the reduction of grid variation thickness level and defect/unit level from 9,184% to 0,492%. In Control stage, it is conducted a new working standard determination and already fixed control process.
Gating Systems for Sizeable Castings from Al Alloys Cast into Ceramic Moulds

Directory of Open Access Journals (Sweden)

I. Stachovec

2012-04-01

Full Text Available In contrast to casting to conventional non-reusable “sand” moulds, for which calculating technique for an optimum design of the gating system is comparatively well-developed, a trial-and-error method is applied mostly for casting to ceramic shell moulds made by the investment casting technology. A technologist selects from gating systems of several types (that are standardized by the foundry mostly on the basis of experience. However, this approach is not sustainable with ever growing demands on quality of castings and also the economy of their fabrication as well as with new types of complex sizeable castings introduced to the production gradually (by new customers from the aircraft industry above all any more. The simulation software may be used as a possible tool for making the process of optimising gating systems more effective.
Yttria coating on quartz mould inner surface for fabrication of metal fuel slug using injection casting process

International Nuclear Information System (INIS)

Vinod, A.V.; Hemanth Kumar, S.; Manivannan, A.; Muralidaran, P.; Anthonysamy, S.; Sudha, R.

2016-01-01

Quartz moulds are used for casting metal alloy of U-Zr slugs by injection casting process. Ceramic (Y_2O_3) coating on inner surface of the quartz mould is provided to avoid silica contamination in the fuel slugs during casting. Experiments were carried out to standardise the coating process and optimising various parameters such as particle size of Y_2O_3, choice of suitable binder, method for application of coating, drying and sintering at high temperature to ensure uniformity and strength of coating. Required Coating thickness of ∼40 μm was achieved on a quartz mould of inner diameter of 4.98±0.01mm. Experimental procedure for coating on inner surface of the quartz tubes using yttrium oxide is described in this work. (author)
Influence of processing parameters on PZT thick films

International Nuclear Information System (INIS)

Huang, Oliver; Bandyopadhyay, Amit; Bose, Susmita

2005-01-01

We have studied influence of processing parameters on the microstructure and ferroelectric properties of lead zirconate titanate (PZT)-based thick films in the range of 5-25 μm. PZT and 2% La-doped PZT thick films were processed using a modified sol-gel process. In this process, PZT- and La-doped PZT powders were first prepared via sol-gel. These powders were calcined and then used with respective sols to form a slurry. Slurry composition was optimized to spin-coat thick films on platinized Si substrate (Si/SiO 2 /Ti/Pt). Spinning rate, acceleration and slurry deposition techniques were optimized to form thick films with uniform thickness and without any cracking. Increasing solids loading was found to enhance the surface smoothness of the film and decrease porosity. Films were tested for their electrical properties and ferroelectric fatigue response. The maximum polarization obtained was 40 μC/cm 2 at 250 kV/cm for PZT thick film and 30 μC/cm 2 at 450 kV/cm for La-doped PZT thick film. After 10 9 cycles of fatiguing at 35 kHz, La-doped PZT showed better resistance for ferroelectric fatigue compared with un-doped PZT films
Sequentially solution-processed, nanostructured polymer photovoltaics using selective solvents

KAUST Repository

Kim, Do Hwan; Mei, Jianguo; Ayzner, Alexander L.; Schmidt, Kristin; Giri, Gaurav; Appleton, Anthony L.; Toney, Michael F.; Bao, Zhenan

2014-01-01

We demonstrate high-performance sequentially solution-processed organic photovoltaics (OPVs) with a power conversion efficiency (PCE) of 5% for blend films using a donor polymer based on the isoindigo-bithiophene repeat unit (PII2T-C10C8) and a fullerene derivative [6,6]-phenyl-C[71]-butyric acid methyl ester (PC71BM). This has been accomplished by systematically controlling the swelling and intermixing processes of the layer with various processing solvents during deposition of the fullerene. We find that among the solvents used for fullerene deposition that primarily swell but do not re-dissolve the polymer underlayer, there were significant microstructural differences between chloro and o-dichlorobenzene solvents (CB and ODCB, respectively). Specifically, we show that the polymer crystallite orientation distribution in films where ODCB was used to cast the fullerene is broad. This indicates that out-of-plane charge transport through a tortuous transport network is relatively efficient due to a large density of inter-grain connections. In contrast, using CB results in primarily edge-on oriented polymer crystallites, which leads to diminished out-of-plane charge transport. We correlate these microstructural differences with photocurrent measurements, which clearly show that casting the fullerene out of ODCB leads to significantly enhanced power conversion efficiencies. Thus, we believe that tuning the processing solvents used to cast the electron acceptor in sequentially-processed devices is a viable way to controllably tune the blend film microstructure. © 2014 The Royal Society of Chemistry.
Effects of Hydrolysed Whey Proteins on the Techno-Functional Characteristics of Whey Protein-Based Films

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Klaus Noller

2013-03-01

Full Text Available Pure whey protein isolate (WPI-based cast films are very brittle due to its strong formation of protein cross-linking of disulphide bonding, hydrogen bonding as well as hydrophobic and electrostatic interactions. However, this strong cross-linking is the reason for its final barrier performance. To overcome film brittleness of whey protein layers, plasticisers like glycerol are used. It reduces intermolecular interactions, increases the mobility of polymer chains and thus film flexibility can be achieved. The objective of this study was to investigate the influence of hydrolysed whey protein isolate (WPI in whey protein isolate-based cast films on their techno-functional properties. Due to the fact, that the addition of glycerol is necessary but at the same time increases the free volume in the film leading to higher oxygen and water vapour permeability, the glycerol concentration was kept constant. Cast films with different ratios of hydrolysed and not hydrolysed WPI were produced. They were characterised in order to determine the influence of the lower molecular weight caused by the addition of hydrolysed WPI on the techno-functional properties. This study showed that increasing hydrolysed WPI concentrations significantly change the mechanical properties while maintaining the oxygen and water vapour permeability. The tensile and elastic film properties decreased significantly by reducing the average molecular weight whereas the yellowish coloration and the surface tension considerably increased. This study provided new data which put researchers and material developers in a position to tailor the characteristics of whey protein based films according to their intended application and further processing.
Engineering scale demonstration of a prospective Cast Stone process

International Nuclear Information System (INIS)

Cozzi, A.; Fowley, M.; Hansen, E.; Fox, K.; Miller, D.; Williams, M.

2014-01-01

This report documents an engineering-scale demonstration with non-radioactive simulants that was performed at SRNL using the Scaled Continuous Processing Facility (SCPF) to fill an 8.5 ft container with simulated Cast Stone grout. The Cast Stone formulation was chosen from the previous screening tests. Legacy salt solution from previous Hanford salt waste testing was adjusted to correspond to the average composition generated from the Hanford Tank Waste Operation Simulator (HTWOS). The dry blend materials, ordinary portland cement (OPC), Class F fly ash, and ground granulated blast furnace slag (GGBFS or BFS), were obtained from Lafarge North America in Pasco, WA. Over three days, the SCPF was used to fill a 1600 gallon container, staged outside the facility, with simulated Cast Stone grout. The container, staged outside the building approximately 60 ft from the SCPF, was instrumented with x-, y-, and z-axis thermocouples to monitor curing temperature. The container was also fitted with two formed core sampling vials. For the operation, the targeted grout production rate was 1.5 gpm. This required a salt solution flow rate of approximately 1 gpm and a premix feed rate of approximately 580 lb/h. During the final day of operation, the dry feed rate was increased to evaluate the ability of the system to handle increased throughput. Although non-steady state operational periods created free surface liquids, no bleed water was observed either before or after operations. The final surface slope at a fill height of 39.5 inches was 1-1.5 inches across the 8.5 foot diameter container, highest at the final fill point and lowest diametrically opposed to the fill point. During processing, grout was collected in cylindrical containers from both the mixer discharge and the discharge into the container. These samples were stored in a humid environment either in a closed box proximal to the container or inside the laboratory. Additional samples collected at these sampling points
Engineering scale demonstration of a prospective Cast Stone process

Energy Technology Data Exchange (ETDEWEB)

Cozzi, A.; Fowley, M.; Hansen, E.; Fox, K.; Miller, D.; Williams, M.

2014-09-30

This report documents an engineering-scale demonstration with non-radioactive simulants that was performed at SRNL using the Scaled Continuous Processing Facility (SCPF) to fill an 8.5 ft container with simulated Cast Stone grout. The Cast Stone formulation was chosen from the previous screening tests. Legacy salt solution from previous Hanford salt waste testing was adjusted to correspond to the average composition generated from the Hanford Tank Waste Operation Simulator (HTWOS). The dry blend materials, ordinary portland cement (OPC), Class F fly ash, and ground granulated blast furnace slag (GGBFS or BFS), were obtained from Lafarge North America in Pasco, WA. Over three days, the SCPF was used to fill a 1600 gallon container, staged outside the facility, with simulated Cast Stone grout. The container, staged outside the building approximately 60 ft from the SCPF, was instrumented with x-, y-, and z-axis thermocouples to monitor curing temperature. The container was also fitted with two formed core sampling vials. For the operation, the targeted grout production rate was 1.5 gpm. This required a salt solution flow rate of approximately 1 gpm and a premix feed rate of approximately 580 lb/h. During the final day of operation, the dry feed rate was increased to evaluate the ability of the system to handle increased throughput. Although non-steady state operational periods created free surface liquids, no bleed water was observed either before or after operations. The final surface slope at a fill height of 39.5 inches was 1-1.5 inches across the 8.5 foot diameter container, highest at the final fill point and lowest diametrically opposed to the fill point. During processing, grout was collected in cylindrical containers from both the mixer discharge and the discharge into the container. These samples were stored in a humid environment either in a closed box proximal to the container or inside the laboratory. Additional samples collected at these sampling points
Colloidal CuInSe2 nanocrystals thin films of low surface roughness

International Nuclear Information System (INIS)

Kergommeaux, Antoine de; Fiore, Angela; Faure-Vincent, Jérôme; Pron, Adam; Reiss, Peter

2013-01-01

Thin-film processing of colloidal semiconductor nanocrystals (NCs) is a prerequisite for their use in (opto-)electronic devices. The commonly used spin-coating is highly materials consuming as the overwhelming amount of deposited matter is ejected from the substrate during the spinning process. Also, the well-known dip-coating and drop-casting procedures present disadvantages in terms of the surface roughness and control of the film thickness. We show that the doctor blade technique is an efficient method for preparing nanocrystal films of controlled thickness and low surface roughness. In particular, by optimizing the deposition conditions, smooth and pinhole-free films of 11 nm CuInSe 2 NCs have been obtained exhibiting a surface roughness of 13 nm root mean square (rms) for a 350 nm thick film, and less than 4 nm rms for a 75 nm thick film. (paper)
Effects of different cooling rates during two casting processes on the microstructures and mechanical properties of extruded Mg–Al–Ca–Mn alloy

International Nuclear Information System (INIS)

Xu, S.W.; Oh-ishi, K.; Kamado, S.; Takahashi, H.; Homma, T.

2012-01-01

Highlights: ► Ordered monolayer GP zone was formed by increasing cooling rate. ► Finer extruded microstructure was obtained by increasing cooling rate. ► Higher number density precipitates was obtained by increasing cooling rate. ► Tensile 0.2% proof stress was increased by 105 MPa by increasing cooling rate. ► Extruded DC-cast alloy shows higher tensile 0.2% proof stress of 409 MPa. - Abstract: In this study, Mg–3.6Al–3.4Ca–0.3Mn (wt.%) (which is denoted AXM4303) alloy ingots were prepared by two casting processes with different cooling rates: permanent mold (PM) casting, which has a lower cooling rate of 10–20 °C/s and direct chill (DC) casting, which has a higher cooling rate of 100–110 °C/s. Then, these two types of AXM4303 alloy ingots were hot extruded at 400 °C under the same conditions. The microstructures of the as-cast and extruded alloy samples were systematically investigated by field-emission scanning electron microscope (FE-SEM), transmission electron microscope (TEM) and electron backscattered diffraction (EBSD) systems. The effects of the different cooling rates during the casting process on the microstructures and mechanical properties of the extruded AXM4303 alloy samples were evaluated. The results show that the strength of the extruded Mg–Al–Ca–Mn alloy can be substantially increased by microstructural control during the casting process. Because the cooling rate of the DC casting process is much faster than the cooling rate of PM casting, the DC-cast AXM4303 has the following properties: (i) the lamellar eutectic structure and dendrite cell size are significantly refined, (ii) the ordered monolayer GP zones enriched with Al and Ca nucleate with no growth, and (iii) most of the Mn remains in solution in the matrix. Thus, after hot extrusion, the DC-cast AXM4303 has finer dynamically recrystallized (DRXed) grain size, finer and more uniformly distributed fragmented eutectic particles, finer planar Al 2 Ca precipitates
Diffusion of C and Cr During Creation of Surface Layer on Cast Steel Casting

Directory of Open Access Journals (Sweden)

Szajnar J.

2014-10-01

Full Text Available In paper a method of improvement in utility properties of unalloyed cast steel casting in result of diffusion of C and Cr in process of creation of surface layer is presented. The aim of paper was determination of diffusion range of basic elements of alloyed surface layer. Moreover a quantitative analysis of carbides phase strengthens alloyed surface layer of casting was carried out. The results of studies shown that important factors of surface layer creation are maximal temperature Tmax on granular insert – cast steel boundary dependent of pouring temperature, granularity Zw of Fe-Cr-C alloy insert and thickness of casting wall gśo. On the basis of obtained results was affirmed that with increase of thickness of casting wall increases range of diffusion in solid state in Fe-Cr-C grains and in liquid state. Moreover the range of Tmax = 13001500oC favours creation of the proper alloyed surface layers on cast steel.
Applying RP-FDM Technology to Produce Prototype Castings Using the Investment Casting Method

Directory of Open Access Journals (Sweden)

M. Macků

2012-09-01

Full Text Available The research focused on the production of prototype castings, which is mapped out starting from the drawing documentation up to theproduction of the casting itself. The FDM method was applied for the production of the 3D pattern. Its main objective was to find out whatdimensional changes happened during individual production stages, starting from the 3D pattern printing through a silicon mouldproduction, wax patterns casting, making shells, melting out wax from shells and drying, up to the production of the final casting itself.Five measurements of determined dimensions were made during the production, which were processed and evaluated mathematically.A determination of shrinkage and a proposal of measures to maintain the dimensional stability of the final casting so as to meetrequirements specified by a customer were the results.
The casting and mechanism of formation of semi-permeable polymer membranes in a microgravity environment

Science.gov (United States)

Vera, I.

The National Electric Company of Venezuela, C.A.D.A.F.E., is sponsoring the development of this experiment which represents Venezuela's first scientific experiment in space. The apparatus for the automatic casting of polymer thin films will be contained in NASA's payload No. G-559 of the Get Away Special program for a future orbital space flight in the U.S. Space Shuttle. Semi-permeable polymer membranes have important applications in a variety of fields, such as medecine, energy, and pharmaceuticals, and in general fluid separation processes such as reverse osmosis, ultra-filtration, and electro-dialysis. The casting of semi-permeable membranes in space will help to identify the roles of convection in determining the strucutre of these membranes.

High performance thin-film composite forward osmosis membrane.

Science.gov (United States)

Yip, Ngai Yin; Tiraferri, Alberto; Phillip, William A; Schiffman, Jessica D; Elimelech, Menachem

2010-05-15

Recent studies show that osmotically driven membrane processes may be a viable technology for desalination, water and wastewater treatment, and power generation. However, the absence of a membrane designed for such processes is a significant obstacle hindering further advancements of this technology. This work presents the development of a high performance thin-film composite membrane for forward osmosis applications. The membrane consists of a selective polyamide active layer formed by interfacial polymerization on top of a polysulfone support layer fabricated by phase separation onto a thin (40 mum) polyester nonwoven fabric. By careful selection of the polysulfone casting solution (i.e., polymer concentration and solvent composition) and tailoring the casting process, we produced a support layer with a mix of finger-like and sponge-like morphologies that give significantly enhanced membrane performance. The structure and performance of the new thin-film composite forward osmosis membrane are compared with those of commercial membranes. Using a 1.5 M NaCl draw solution and a pure water feed, the fabricated membranes produced water fluxes exceeding 18 L m(2-)h(-1), while consistently maintaining observed salt rejection greater than 97%. The high water flux of the fabricated thin-film composite forward osmosis membranes was directly related to the thickness, porosity, tortuosity, and pore structure of the polysulfone support layer. Furthermore, membrane performance did not degrade after prolonged exposure to an ammonium bicarbonate draw solution.
High Performance Thin-Film Composite Forward Osmosis Membrane

KAUST Repository

Yip, Ngai Yin

2010-05-15

Recent studies show that osmotically driven membrane processes may be a viable technology for desalination, water and wastewater treatment, and power generation. However, the absence of a membrane designed for such processes is a significant obstacle hindering further advancements of this technology. This work presents the development of a high performance thin-film composite membrane for forward osmosis applications. The membrane consists of a selective polyamide active layer formed by interfacial polymerization on top of a polysulfone support layer fabricated by phase separation onto a thin (40 μm) polyester nonwoven fabric. By careful selection of the polysulfone casting solution (i.e., polymer concentration and solvent composition) and tailoring the casting process, we produced a support layer with a mix of finger-like and sponge-like morphologies that give significantly enhanced membrane performance. The structure and performance of the new thin-film composite forward osmosis membrane are compared with those of commercial membranes. Using a 1.5 M NaCl draw solution and a pure water feed, the fabricated membranes produced water fluxes exceeding 18 L m2-h-1, while consistently maintaining observed salt rejection greater than 97%. The high water flux of the fabricated thin-film composite forward osmosis membranes was directly related to the thickness, porosity, tortuosity, and pore structure of the polysulfone support layer. Furthermore, membrane performance did not degrade after prolonged exposure to an ammonium bicarbonate draw solution. © 2010 American Chemical Society.
Development of polymer nano composite patterns using fused deposition modeling for rapid investment casting process

Science.gov (United States)

Vivek, Tiwary; Arunkumar, P.; Deshpande, A. S.; Vinayak, Malik; Kulkarni, R. M.; Asif, Angadi

2018-04-01

Conventional investment casting is one of the oldest and most economical manufacturing techniques to produce intricate and complex part geometries. However, investment casting is considered economical only if the volume of production is large. Design iterations and design optimisations in this technique proves to be very costly due to time and tooling cost for making dies for producing wax patterns. However, with the advent of Additive manufacturing technology, plastic patterns promise a very good potential to replace the wax patterns. This approach can be very useful for low volume production & lab requirements, since the cost and time required to incorporate the changes in the design is very low. This research paper discusses the steps involved for developing polymer nanocomposite filaments and checking its suitability for investment castings. The process parameters of the 3D printer machine are also optimized using the DOE technique to obtain mechanically stronger plastic patterns. The study is done to develop a framework for rapid investment casting for lab as well as industrial requirements.
Photophysical Studies of Spin Cast Polymer Films

Science.gov (United States)

1988-07-13

Polymeric Materials contained research presentations on fundamental radiation chemistry and physics as well as on technological applications of polymer ...on Polymeric Materials," X~os Hoos. ueensland. Australia., August 16-19, 1987 ,7 COSAII CODES I&. SUBJECT TEAMS (Conuo an itwre it r~,*Ctzy Mid od@0ty...by biOck mumblrJ _ILO GR UP SU8 -GaOUP 9. AaSTkRAC7T (COn1nue an r*"wne it noatamey and iwaf by bWok nuffltr) Snim casting is a commonly used technique
Application of a tablet film coating model to define a process-imposed transition boundary for robust film coating.

Science.gov (United States)

van den Ban, Sander; Pitt, Kendal G; Whiteman, Marshall

2018-02-01

A scientific understanding of interaction of product, film coat, film coating process, and equipment is important to enable design and operation of industrial scale pharmaceutical film coating processes that are robust and provide the level of control required to consistently deliver quality film coated product. Thermodynamic film coating conditions provided in the tablet film coating process impact film coat formation and subsequent product quality. A thermodynamic film coating model was used to evaluate film coating process performance over a wide range of film coating equipment from pilot to industrial scale (2.5-400 kg). An approximate process-imposed transition boundary, from operating in a dry to a wet environment, was derived, for relative humidity and exhaust temperature, and used to understand the impact of the film coating process on product formulation and process control requirements. This approximate transition boundary may aid in an enhanced understanding of risk to product quality, application of modern Quality by Design (QbD) based product development, technology transfer and scale-up, and support the science-based justification of critical process parameters (CPPs).
Polymeric bionanocomposite cast thin films with in situ laccase-catalyzed polymerization of dopamine for biosensing and biofuel cell applications.

Science.gov (United States)

Tan, Yueming; Deng, Wenfang; Li, Yunyong; Huang, Zhao; Meng, Yue; Xie, Qingji; Ma, Ming; Yao, Shouzhuo

2010-04-22

We report here on the facile preparation of polymer-enzyme-multiwalled carbon nanotubes (MWCNTs) cast films accompanying in situ laccase (Lac)-catalyzed polymerization for electrochemical biosensing and biofuel cell applications. Lac-catalyzed polymerization of dopamine (DA) as a new substrate was examined in detail by UV-vis spectroscopy, cyclic voltammetry, quartz crystal microbalance, and scanning electron microscopy. Casting the aqueous mixture of DA, Lac and MWCNTs on a glassy carbon electrode (GCE) yielded a robust polydopamine (PDA)-Lac-MWCNTs/GCE that can sense hydroquinone with 643 microA mM(-1) cm(-2) sensitivity and 20-nM detection limit (S/N = 3). The DA substrate yielded the best biosensing performance, as compared with aniline, o-phenylenediamine, or o-aminophenol as the substrate for similar Lac-catalyzed polymerization. Casting the aqueous mixture of DA, glucose oxidase (GOx), Lac, and MWCNTs on a Pt electrode yielded a robust PDA-GOx-Lac-MWCNTs/Pt electrode that exhibits glucose-detection sensitivity of 68.6 microA mM(-1) cm(-2). In addition, 2,2'-azinobis (3-ethylbenzothiazoline-6-sulfonate) diammonium salt (ABTS) was also coimmobilized to yield a PDA-Lac-MWCNTs-ABTS/GCE that can effectively catalyze the reduction of O(2), and it was successfully used as the biocathode of a membraneless glucose/O(2) biofuel cell (BFC) in pH 5.0 Britton-Robinson buffer. The proposed biomacromolecule-immobilization platform based on enzyme-catalyzed polymerization may be useful for preparing many other multifunctional polymeric bionanocomposites for wide applications.
Temperature-dependent structural properties of P3HT films

Energy Technology Data Exchange (ETDEWEB)

Grigorian, S; Joshi, S; Pietsch, U, E-mail: grigorian@physik.uni-siegen.de [Institute of Physics, University Siegen, Walter Flex Strasse 3, D-57068, Siegen (Germany)

2010-11-15

Structural investigations of spin coated and drop cast poly(3-hexylthiophene) P3HT films have been performed under x-ray grazing incidence geometry. Drop cast films revealed to be highly oriented and crystalline and only slightly modify with the temperature. In contrast, spin coated films provided random orientational distribution of nanocrystallites and undergo significant morphological and structural changes during annealing. Interestingly, spin coated films of low and high molecular weight fractions behavior differently as a function of temperature. Crystalline domains of the low molecular weight fractions have been decreased, and, in contrast, we found an improvement of crystallinity of high molecular weight fraction with increase of the temperature.
Temperature-dependent structural properties of P3HT films

International Nuclear Information System (INIS)

Grigorian, S; Joshi, S; Pietsch, U

2010-01-01

Structural investigations of spin coated and drop cast poly(3-hexylthiophene) P3HT films have been performed under x-ray grazing incidence geometry. Drop cast films revealed to be highly oriented and crystalline and only slightly modify with the temperature. In contrast, spin coated films provided random orientational distribution of nanocrystallites and undergo significant morphological and structural changes during annealing. Interestingly, spin coated films of low and high molecular weight fractions behavior differently as a function of temperature. Crystalline domains of the low molecular weight fractions have been decreased, and, in contrast, we found an improvement of crystallinity of high molecular weight fraction with increase of the temperature.
Applying RP-FDM Technology to Produce Prototype Castings Using the Investment Casting Method

Directory of Open Access Journals (Sweden)

Macků M.

2012-09-01

Full Text Available The research focused on the production of prototype castings, which is mapped out starting from the drawing documentation up to the production of the casting itself. The FDM method was applied for the production of the 3D pattern. Its main objective was to find out what dimensional changes happened during individual production stages, starting from the 3D pattern printing through a silicon mould production, wax patterns casting, making shells, melting out wax from shells and drying, up to the production of the final casting itself. Five measurements of determined dimensions were made during the production, which were processed and evaluated mathematically. A determination of shrinkage and a proposal of measures to maintain the dimensional stability of the final casting so as to meet requirements specified by a customer were the results.
Cast dielectric composite linear accelerator

Science.gov (United States)

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

2009-11-10

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

Directory of Open Access Journals (Sweden)

Stradomski Z.

2013-09-01

Full Text Available The investigations were inspired with the problem of cracking of steel castings during the production process. A single mechanism of decohesion - the intergranular one - occurs in the case of hot cracking, while a variety of structural factors is decisive for hot cracking initiation, depending on chemical composition of the cast steel. The low-carbon and low-alloyed steel castings crack due to the presence of the type II sulphides, the cause of cracking of the high-carbon tool cast steels is the net of secondary cementite and/or ledeburite precipitated along the boundaries of solidified grains. Also the brittle phosphor and carbide eutectics precipitated in the final stage solidification are responsible for cracking of castings made of Hadfield steel. The examination of mechanical properties at 1050°C revealed low or very low strength of high-carbon cast steels.
Application of digital pattern-less molding technology to produce art casting

Directory of Open Access Journals (Sweden)

Chen Li1

2014-11-01

Full Text Available Compared with the conventional casting process, digital pattern-less casting technology has many advantages such as good machining accuracy, a short processing cycle, and low production cost. It is a new rapid manufacturing technology for castings, integrated with CAD/CAM, casting, CNC machining and many other advanced technologies. With this digital casting technology, no pattern is needed for making molds; it is precise, flexible, and green. Usually, art castings have complex structures and are made in small batches or even made in a single-piece, especially for large-sized art castings. So it has the shortcomings of high cost, low efficiency and long time for making a pattern to produce art castings with the conventional casting processes. However, the digital pattern-less casting technology can be applied to fabricate art castings, since it can greatly shorten the manufacturing cycle and lower the production cost, thus having a very good prospect. In this study, based on the digital pattern-less casting technology, a plaque casting with artistic Chinese characters (a Chinese poem was designed and manufactured, and the production process was demonstrated in detail.
A new radiochromic film for radiation processing

International Nuclear Information System (INIS)

Sidney, L.N.; Lynch, D.C.; Willett, P.S.; Englund, W.J.

1990-01-01

Acid-sensitive leuco dyes in combination with a chlorine-containing polymer have been used to make a new kind of radiochromic film for radiation processing. When exposed to gamma, electron beam, or high intensity ultraviolet radiation, these films undergo a color change from colorless to royal blue, fuschia, or black, depending on the dye. The dose response for gamma and electron beam radiation has been characterized using reflection and transmission spectrophotometry over an adsorbed dose range of 1 to 100 kGy. The primary features of the films include improved color stability before and after irradiation and improved moisture resistance. The response and stability of the films make them useful for indicator (qualitative) or dosimeter (quantitative) films or labels for sterilization of medical products, food (especially meat, poultry, and spices), pharmaceuticals, and cosmetics, and the crosslinking of plastics, and the curing of polymer coatings. Large pieces of the film could be used in dose mapping when setting up and validating radiation processes and medical treatments
Fabrication of a large area cathode-supported thin electrolyte film for solid oxide fuel cells via tape casting and co-sintering techniques

Energy Technology Data Exchange (ETDEWEB)

Zhao, Chunhua; Liu, Renzhu; Wang, Shaorong; Wen, Tinglian [Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

2009-04-15

A large area cathode-supported electrolyte film, comprising porous (La{sub 0.8}Sr{sub 0.2}){sub 0.95}MnO{sub 3} (LSM95) cathode substrate, LSM95/Zr{sub 0.89}Sc{sub 0.1}Ce{sub 0.01}O{sub 2-x} (SSZ) cathode active layer, and SSZ electrolyte, has been successfully fabricated by tape casting and co-sintering techniques. The interface reaction between cathode and electrolyte was inhibited by using A-site deficient LSM. A dense enough SSZ thin film with a thickness of {proportional_to}26 {mu}m was obtained at 1250 C. By using Pt as anode, the obtained single cell reached the maximum power density of 0.54 W cm{sup -2} at 800 C in O{sub 2}/humidified H{sub 2}, with open circuit voltage (OCV) value of 1.08 V. (author)
Microstructural and mechanical evolutions during the forging step of the COBAPRESS, a casting/forging process

Science.gov (United States)

Perrier, Frédéric; Desrayaud, Christophe; Bouvier, Véronique

Aluminum casting/forging processes are used to produce parts for the automotive industry. In this study, we examined the influence of the forging step on the microstructure and the mechanical properties of an A356 aluminum alloy modified with strontium. Firstly, a design of samples which allows us to test mechanically the alloy before and after forging was created. A finite element analysis with the ABAQUS software predicts a maximum of strain in the core of the specimens. Observations with the EBSD technique confirm a more intense sub-structuration of the dendrite cells in this zone. Yield strength, ultimate tensile strength, elongation and fatigue lives were then improved for the casting/forging samples compared to the only cast specimens. The closure of the porosities and the improvement of the surface quality during the forging step enhance also the fatigue resistance of the samples.
Nuclear-waste encapsulation by metal-matrix casting

International Nuclear Information System (INIS)

Nelson, R.G.; Nesbitt, J.F.; Slate, S.C.

1981-05-01

Several encapsulation casting processes are described that were developed or used at the Pacific Northwest Laboratory to embed simulated high-level wastes of two different forms (glass marbles and ceramic pellets) in metal matrices. Preliminary evaluations of these casting processes and the products are presented. Demonstrations have shown that 5- to 10-mm-dia glass marbles can be encapsulated on an engineering scale with lead or lead alloys by gravity or vacuum processes. Marbles approx. 12 mm in dia were successfully encapsulated in a lead alloy on a production scale. Also, 4- to 9-mm-dia ceramic pellets in containers of various sizes were completely penetrated and the individual pellets encased with aluminum-12 wt % silicon alloy by vacuum processes. Indications are that of the casting processes tested, aluminum 12 wt % silicon alloy vacuum-cast around ceramic pellets had the highest degree of infiltration or coverage of pellet surfaces
Development of expert systems for modeling of technological process of pressure casting on the basis of artificial intelligence

Science.gov (United States)

Gavarieva, K. N.; Simonova, L. A.; Pankratov, D. L.; Gavariev, R. V.

2017-09-01

In article the main component of expert system of process of casting under pressure which consists of algorithms, united in logical models is considered. The characteristics of system showing data on a condition of an object of management are described. A number of logically interconnected steps allowing to increase quality of the received castings is developed
The application of optical measurements for the determination of accuracy of gear wheels casts manufactured in the RT/RP process

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G. Budzik

2010-01-01

Full Text Available The article discusses the possibilities of using optical measurements for defining the geometric accuracy of gear wheels casts manufactured in the rapid prototyping process. The tested gear wheel prototype was cast using an aluminum alloy. The casting mould was made by means of the three-dimensional print method (3DP with the use of a Z510 Spectrum device. The aim of the tests was to determine the geometric accuracy of the cast made by the ZCast technology in the rapid prototyping process. The tests were conducted with the use of the coordinate optical measuring method and a GOM measuring device. The prototype measurements were made in the scanning mode. The results of the measurements, saved in the STL format with the use of the scanning device software, were compared with the gear wheel 3D-CAD nominal model. The measurements enabled the determination of the real accuracy of prototypes manufactured in casting moulds by means of the ZCast technology. The selection of the measuring method was also analyzed in terms of measurement accuracy and the RP technology precision.
Optimizing the Gating System for Steel Castings

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Jan Jezierski

2018-04-01

Full Text Available The article presents the attempt to optimize a gating system to produce cast steel castings. It is based on John Campbell’s theory and presents the original results of computer modelling of typical and optimized gating systems for cast steel castings. The current state-of-the-art in cast steel casting foundry was compared with several proposals of optimization. The aim was to find a compromise between the best, theoretically proven gating system version, and a version that would be affordable in industrial conditions. The results show that it is possible to achieve a uniform and slow pouring process even for heavy castings to preserve their internal quality.
Fiber laser cladding of nickel-based alloy on cast iron

Energy Technology Data Exchange (ETDEWEB)

Arias-González, F., E-mail: felipeag@uvigo.es [Applied Physics Dpt., University of Vigo, EEI, Lagoas-Marcosende, Vigo E-36310 (Spain); Val, J. del [Applied Physics Dpt., University of Vigo, EEI, Lagoas-Marcosende, Vigo E-36310 (Spain); Comesaña, R. [Materials Engineering, Applied Mechanics and Construction Dpt., University of Vigo, EEI, Lagoas-Marcosende, Vigo E-36310 (Spain); Penide, J.; Lusquiños, F.; Quintero, F.; Riveiro, A.; Boutinguiza, M.; Pou, J. [Applied Physics Dpt., University of Vigo, EEI, Lagoas-Marcosende, Vigo E-36310 (Spain)

2016-06-30

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

Thin film plasma coatings from dielectric free-flowing materials

International Nuclear Information System (INIS)

Timofeeva, L.A.; Katrich, S.A.; Solntsev, L.A.

1994-01-01

Fabrication of thin film plasma coatings from insulating free-flowing materials is considered. Molybdenum-tart ammonium coating of 3...5 μ thickness deposited on glassy carbon, aluminium, silicon, nickel, cast iron and steel substrates in 'Bulat-ZT' machine using insulating free-flowing materials cathod was found to form due to adsorption, absorption and dissuasion processes. The use of insulating free-flowing materials coatings allow to exclude pure metals cathods in plasma-plating process
Physiochemical Characterization of Iodine (V Oxide Part II: Morphology and Crystal Structure of Particulate Films

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Brian K. Little

2015-11-01

Full Text Available In this study, the production of particulate films of iodine (V oxides is investigated. The influence that sonication and solvation of suspended particles in various alcohol/ketone/ester solvents have on the physical structure of spin or drop cast films is examined in detail with electron microscopy, powder x-ray diffraction, and UV-visible absorption spectroscopy. Results indicate that sonicating iodine oxides in alcohol mixtures containing trace amounts of water decreases deposited particle sizes and produces a more uniform film morphology. UV-visible spectra of the pre-cast suspensions reveal that for some solvents, the iodine oxide oxidizes the solvent, producing I2 and lowering the pH of the suspension. Characterizing the crystals within the cast films reveal their composition to be primarily HI3O8, their orientations to exhibit a preferential orientation, and their growth to be primarily along the ac-plane of the crystal, enhanced at higher spin rates. Spin-coating at lower spin rates produces laminate-like particulate films versus higher density, one-piece films of stacked particles produced by drop casting. The particle morphology in these films consists of a combination of rods, plates, cubes, and rhombohedra structure.
Breakout Prediction Based on BP Neural Network in Continuous Casting Process

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Zhang Ben-guo

2016-01-01

Full Text Available An improved BP neural network model was presented by modifying the learning algorithm of the traditional BP neural network, based on the Levenberg-Marquardt algorithm, and was applied to the breakout prediction system in the continuous casting process. The results showed that the accuracy rate of the model for the temperature pattern of sticking breakout was 96.43%, and the quote rate was 100%, that verified the feasibility of the model.
Nodular cast iron and casting monitoring

Directory of Open Access Journals (Sweden)

S. Pietrowski

2008-10-01

Full Text Available In this paper quality monitoring of nodular cast iron and casting made of it is presented. A control system of initial liquid cast iron to spheroidization, after spheroidization and inoculation with using of TDA method was shown. An application of an ultrasonic method to assessment of the graphite form and the metal matrix microstructure of castings was investigated.
Energy efficiency opportunities in the production process of cast iron foundries: An experience in Italy

International Nuclear Information System (INIS)

Lazzarin, Renato M.; Noro, Marco

2015-01-01

Foundry sector is one of the most energy intensive in industry. Energy audits performed in 5 Italian cast iron foundries allowed to identify energy utilization in the various processes that from the melting of the iron arrive at the finishing of the casting. Main equipment was surveyed, evaluating the influence on the overall energy consumption, producing a detailed analysis of energy use per department and energy performance indexes. A separate study was carried out for foundries with induction furnaces and cold or hot blast cupolas. Possibilities of heat recovery was identified particularly in combustion air preheating, but also for building heating or to power direct cycles to produce electricity. Better insulation and new insulating materials can improve the efficiency and the quality of the processes. Suggestions are supplied in the various foundry departments for energy saving. Possible energy saving actions on the service plants will be dealt with in a separate paper. - Highlights: • The Authors performed energy audits in 5 Italian cast iron foundries. • Main equipment was surveyed, evaluating the influence on the overall energy consumption. • An analysis of energy use per department and energy performance indexes was performed. • Possibilities of heat recovery were identified in combustion air preheating and for building heating. • Better and new insulating materials were analyzed to improve the efficiency and process quality.
Investment casting: parameters, application and recent development

International Nuclear Information System (INIS)

Zaid, A.I.O.

2007-01-01

Investment casting process, also referred to as the lost wax method and as precision casting, has been known for more than 6000 years. However, industry paid little attention to the process until the urgent military demands of World War 1 overtaxed the machine tool industry and short cuts were then needed to provide finished tools and precision parts, avoiding time-consuming in machining and assembly. The use of the process for the production of commercial casting has grown in the second half of the 20th century. The process is highly flexible and can handle great variety of parts which are difficult or even not possible to be produced by forging or other casting methods. In this paper, the investment casting process, its applications, advantages and limitations together with the parameters affecting it as related to pattern material, cluster, slurry and molten metal are given and discussed. Furthermore, the recent developments in the process particularly in manufacturing parts made of superalloys e.g nickel-base alloys are given and discussed. The striking fact that the process has advanced further in the last 60 years than it has in the previous 6000 years ensures that in the coming years of this century development in the process and its application will continue to advance in the interest of achieving higher quality and precision which can meet the critical performance standards being imposed. (author)
Friction and wear characteristics of Al-Cu/C composites synthesized using partial liquid phase casting process

International Nuclear Information System (INIS)

Ng, W.B.; Gupta, M.; Lim, S.C.

1997-01-01

During the sliding of aluminium alloys dispersed with graphite particulates, a layer of graphite is usually present at the sliding interface. This tribo-layer significantly reduces the amount of direct metal-to-metal contact, giving rise to low friction and a low rate of wear, making these composites useful candidate materials for anti-friction applications. Such self-lubricating composites are commonly fabricated via the squeeze casting, slurry casting or powder metallurgy route. These processes are expensive while the less-expensive conventional casting route is limited by the agglomeration of graphite particles in the composites, giving rise to poor mechanical properties. In this work, graphite particulate-reinforced Al-4.5 wt.% Cu composites with two effective graphite contents (Al-4.5 Cu/4.2 wt.% C and Al-4.5 Cu/6.8 wt.% C) were synthesized through an innovative partial liquid phase casting (rheocasting) technique, which is a modification of the conventional casting process. Unlubricated (without the use of conventional liquid lubrication) friction and wear performance of these composites as well as the un-reinforced aluminium alloy was determined using a pin-on-disk tester. The results revealed that the graphite-reinforced composites have a higher wear rate than the un-reinforced matrix alloy while their frictional characteristics are very similar within the range of testing conditions. Combining these with the information gathered from worn-surface examinations and wear-debris analysis, it is suggested that there exists a certain threshold for the amount and size of graphite particulates in these composites to enable them to have improved tribological properties. (Copyright (c) 1997 Elsevier Science B.V., Amsterdam. All rights reserved.)
Nonaqueous slip casting of high temperature ceramic superconductors using an investment casting technique

Science.gov (United States)

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

1993-01-01

A process for slip casting ceramic articles that does not employ parting agents and affords the casting of complete, detailed, precision articles that do not possess parting lines is presented. This process is especially useful for high temperature superconductors and water-sensitive ceramics. A wax pattern for a shell mold is provided, and an aqueous mixture of a calcium sulfate-bonded investment material is applied as a coating to the wax pattern. The coated wax pattern is then dried, followed by curing to vaporize the wax pattern and leave a shell mold of the calcium sulfate-bonded investment material. The shell mold is cooled to room temperature, and a ceramic slip, created by dispersing a ceramic powder in an organic liquid, is poured therein. After a ceramic shell of desired thickness or a solid article has set up in the shell mold, excess ceramic slip is poured out. The shell mold is misted with water and peeled away from the ceramic article, after which the ceramic is fired to provide a complete, detailed, precision, high temperature superconductive ceramic article without parting lines. The casting technique may take place in the presence of a magnetic field to orient the ceramic powders during the casting process.
Design and characterization of copaiba oil/alginate films for wound dressings application: Effect of copaiba oil concentration on the film properties

International Nuclear Information System (INIS)

Martins, Aryane Christine Neves; Silva, Classius Ferreira da

2016-01-01

Full text: Polymeric films have been used as wound dressings for burns and wounds. The healing, anti-inflammatory and antibiotic properties of these films can be induced or potentiated by the incorporation of bioactive like herbal medicines. In this work, alginate films were produced incorporating copaiba oil (Copaifera L.) which has the properties as mentioned above. The casting technique was used to prepare the copaiba oil/alginate films. The copaiba oil was previously emulsified in an alginate solution, and the emulsion was cast in a Petri dish before slow drying. The copaiba oil concentration was evaluated. The films were characterized according to the permeability to water vapor, differential scanning calorimetry, scanning electron microscopy, X-ray diffraction, and mechanical properties. The emulsified films showed appropriate properties for use as wound dressings. The main effect on the properties occurred in the highest concentration of copaiba oil. (author)
Design and characterization of copaiba oil/alginate films for wound dressings application: Effect of copaiba oil concentration on the film properties

Energy Technology Data Exchange (ETDEWEB)

Martins, Aryane Christine Neves; Silva, Classius Ferreira da, E-mail: aryanemartins_@hotmail.com [Universidade Federal de Sao Paulo (UNIFESP), Diadema, SP (Brazil)

2016-07-01

Full text: Polymeric films have been used as wound dressings for burns and wounds. The healing, anti-inflammatory and antibiotic properties of these films can be induced or potentiated by the incorporation of bioactive like herbal medicines. In this work, alginate films were produced incorporating copaiba oil (Copaifera L.) which has the properties as mentioned above. The casting technique was used to prepare the copaiba oil/alginate films. The copaiba oil was previously emulsified in an alginate solution, and the emulsion was cast in a Petri dish before slow drying. The copaiba oil concentration was evaluated. The films were characterized according to the permeability to water vapor, differential scanning calorimetry, scanning electron microscopy, X-ray diffraction, and mechanical properties. The emulsified films showed appropriate properties for use as wound dressings. The main effect on the properties occurred in the highest concentration of copaiba oil. (author)
Helical instability in film blowing process: Analogy to buckling instability

Science.gov (United States)

Lee, Joo Sung; Kwon, Ilyoung; Jung, Hyun Wook; Hyun, Jae Chun

2017-12-01

The film blowing process is one of the most important polymer processing operations, widely used for producing bi-axially oriented film products in a single-step process. Among the instabilities observed in this film blowing process, i.e., draw resonance and helical motion occurring on the inflated film bubble, the helical instability is a unique phenomenon portraying the snake-like undulation motion of the bubble, having the period on the order of few seconds. This helical instability in the film blowing process is commonly found at the process conditions of a high blow-up ratio with too low a freezeline position and/or too high extrusion temperature. In this study, employing an analogy to the buckling instability for falling viscous threads, the compressive force caused by the pressure difference between inside and outside of the film bubble is introduced into the simulation model along with the scaling law derived from the force balance between viscous force and centripetal force of the film bubble. The simulation using this model reveals a close agreement with the experimental results of the film blowing process of polyethylene polymers such as low density polyethylene and linear low density polyethylene.
Reengineering of Permanent Mould Casting with Lean Manufacturing Methods

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R. Władysiak

2007-07-01

Full Text Available At the work were introduced main areas of production system project of casts produced in permanent moulds, that constitutes reengineering of conventional production system according to Lean Manufacturing (LM methods. New resolution of cooling of dies with water mist was shown to casting of car wheels made from aluminium alloys in low pressure casting process. It was implemented as a part of goal-oriented project in R.H. Alurad Sp.z o.o. in Gorzyce. Its using intensifies solidification and self-cooling of casts shortening the time of casting cycle by the 30%. It was described reorganizing casting stations into multi-machines cells production and the process of their fast tool’s exchange with applying the SMED method. A project of the system was described controlling the production of the foundry with the computer aided light Kanban system. A visualization of the process was shown the production of casts with use the value stream mapping method. They proved that applying casting new method in the technology and LM methods allowed to eliminate down-times, to reduce the level of stocks, to increase the productivity and the flow of the castings production.
Fabrication and processing of polymer solar cells: A review of printing and coating techniques

DEFF Research Database (Denmark)

Krebs, Frederik C

2009-01-01

Polymer solar cells are reviewed in the context of the processing techniques leading to complete devices. A distinction is made between the film-forming techniques that are used currently such as spincoating, doctor blading and casting and the, from a processing point of view, more desirable film...... are described with focus on the particular advantages and disadvantages associated with each case....
Synthesis of thin films by the pyrosol process

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Tucić Aleksandar

2002-01-01

Full Text Available Among many aerosol routes, the Pyrosol process, due to its simplicity, low cost and quality of obtained films, represents a promising technique for the synthesis of thin films. The pyrosol process is based on the transport and pyrolysls of an aerosol of processor solution, generated in an ultrasonic atomizer, on a heated substrate. The theoretical principles of the pyrosol process are presented in this paper, as well as the influence of some synthesis parameters on the deposition of SnO2 thin films.
Rough case-based reasoning system for continues casting

Science.gov (United States)

Su, Wenbin; Lei, Zhufeng

2018-04-01

The continuous casting occupies a pivotal position in the iron and steel industry. The rough set theory and the CBR (case based reasoning, CBR) were combined in the research and implementation for the quality assurance of continuous casting billet to improve the efficiency and accuracy in determining the processing parameters. According to the continuous casting case, the object-oriented method was applied to express the continuous casting cases. The weights of the attributes were calculated by the algorithm which was based on the rough set theory and the retrieval mechanism for the continuous casting cases was designed. Some cases were adopted to test the retrieval mechanism, by analyzing the results, the law of the influence of the retrieval attributes on determining the processing parameters was revealed. A comprehensive evaluation model was established by using the attribute recognition theory. According to the features of the defects, different methods were adopted to describe the quality condition of the continuous casting billet. By using the system, the knowledge was not only inherited but also applied to adjust the processing parameters through the case based reasoning method as to assure the quality of the continuous casting and improve the intelligent level of the continuous casting.
Pectin- and gelatin-based film: effect of gamma irradiation on the mechanical properties and biodegradation

Energy Technology Data Exchange (ETDEWEB)

Jo, Cheorun; Kang, Hojin; Lee, Na Young; Kwon, Joong Ho; Byun, Myung Woo E-mail: mwbyun@kaeri.re.kr

2005-04-01

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

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Jaworski J.

2016-09-01

Full Text Available Ensuring the required quality of castings is an important part of the production process. The quality control should be carried out in a fast and accurate way. These requirements can be met by the use of an optical measuring system installed on the arm of an industrial robot. In the article a methodology for assessing the quality of robotic measurement system to control certain feature of the casting, based on the analysis of repeatability and reproducibility is presented. It was shown that industrial robots equipped with optical measuring systems have the accuracy allowing their use in the process of dimensional control of castings manufactured by lost-wax process, permanent-mould casting, and pressure die-casting.
Microstructure And Mechanical Properties Of An Al-Zn-Mg-Cu Alloy Produced By Gravity Casting Process

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Saikawa S.

2015-06-01

Full Text Available High-strength aluminum alloy are widely used for structural components in aerospace, transportation and racing car applications. The objective of this study is to enhance the strength of the Al-Zn-Mg-Cu alloy used for gravity casting process. All alloys cast into stepped-form sand mold (Sand-mold Casting; SC and Y-block shaped metal mold(Permanent mold Casting; PC C and then two –step aged at 398-423 K after solution treated at 743 K for 36 ks. The tensile strength and total elongation of the two-step aged SC alloys were 353-387 MPa and about 0.4% respectively. This low tensile properties of the SC alloys might be caused by remaining of undissolved crystallized phase such as Al2CuM, MgZn2 and Al-Fe-Cu system compounds. However, good tensile properties were obtained from PC alloys, tensile strength and 0.2% proof stress and elongation were 503-537 MPa, 474-519 MPa and 1.3-3.3%.
Stainless steel fibre reinforced aluminium matrix composites processed by squeeze casting: relationship between processing conditions and interfacial microstructure

International Nuclear Information System (INIS)

Colin, C.; Marchal, Y.; Boland, F.; Delannay, F.

1993-01-01

This work investigates the influence of some processing parameters on the extent of interfacial reaction in squeeze cast aluminium matrix composites reinforced with 12 μm diameter, continuous stainless steel fibres. The average thickness of the reaction layer at fibre/matrix interfaces was measured by image analysis. When casting was made in a die at room temperature, the thickness of the reaction layer was affected on a distance of several mm from the lateral surface or from the bottom of the preform. The results indicate that the major part of the reaction occurs before solidification of the liquid metal. The control of the extent of interfacial reaction can be achieved through optimization of both infiltration parameters and features of the preform such as the volume fraction of the fibres. (orig.)
Colloidal CuInSe2 nanocrystals thin films of low surface roughness

Science.gov (United States)

de Kergommeaux, Antoine; Fiore, Angela; Faure-Vincent, Jérôme; Pron, Adam; Reiss, Peter

2013-03-01

Thin-film processing of colloidal semiconductor nanocrystals (NCs) is a prerequisite for their use in (opto-)electronic devices. The commonly used spin-coating is highly materials consuming as the overwhelming amount of deposited matter is ejected from the substrate during the spinning process. Also, the well-known dip-coating and drop-casting procedures present disadvantages in terms of the surface roughness and control of the film thickness. We show that the doctor blade technique is an efficient method for preparing nanocrystal films of controlled thickness and low surface roughness. In particular, by optimizing the deposition conditions, smooth and pinhole-free films of 11 nm CuInSe2 NCs have been obtained exhibiting a surface roughness of 13 nm root mean square (rms) for a 350 nm thick film, and less than 4 nm rms for a 75 nm thick film. Invited talk at the 6th International Workshop on Advanced Materials Science and Nanotechnology, 30 October-2 November 2012, Ha Long, Vietnam.

Biodegradability and mechanical properties of starch films from Andean crops.

Science.gov (United States)

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

2011-05-01

Different Andean crops were used to obtain starches not previously reported in literature as raw material for the production of biodegradable polymers. The twelve starches obtained were used to prepare biodegradable films by casting. Water and glycerol were used as plasticizers. The mechanical properties of the starch based films were assessed by means of tensile tests. Compost tests and FTIR tests were carried out to assess biodegradability of films. The results show that the mechanical properties (UTS, Young's modulus and elongation at break) of starch based films strongly depend on the starch source used for their production. We found that all the starch films prepared biodegrade following a three stage process and that the weight loss rate of all the starch based films tested was higher than the weight loss rate of the cellulose film used as control. Copyright © 2011 Elsevier B.V. All rights reserved.
Aluminium Foam and Magnesium Compound Casting Produced by High-Pressure Die Casting

Directory of Open Access Journals (Sweden)

Iban Vicario

2016-01-01

Full Text Available Nowadays, fuel consumption and carbon dioxide emissions are two of the main focal points in vehicle design, promoting the reduction in the weight of vehicles by using lighter materials. The aim of the work is to evaluate the influence of different aluminium foams and injection parameters in order to obtain compound castings with a compromise between the obtained properties and weight by high-pressure die cast (HPDC using aluminium foams as cores into a magnesium cast part. To evaluate the influence of the different aluminium foams and injection parameters on the final casting products quality, the type and density of the aluminium foam, metal temperature, plunger speed, and multiplication pressure have been varied within a range of suitable values. The obtained compound HPDC castings have been studied by performing visual and RX inspections, obtaining sound composite castings with aluminium foam cores. The presence of an external continuous layer on the foam surface and the correct placement of the foam to support injection conditions permit obtaining good quality parts. A HPDC processed magnesium-aluminium foam composite has been developed for a bicycle application obtaining a suitable combination of mechanical properties and, especially, a reduced weight in the demonstration part.
Effect of Ethanolamines on Corrosion Inhibition of Ductile Cast Iron in Nitrite Containing Solutions

International Nuclear Information System (INIS)

Kim, K. T.; Kim, Y. S.; Chang, H. Y.; Lim, B. T.; Park, H. B.

2016-01-01

In this work, synergistic corrosion inhibition effect of nitrite and 3 kinds of ethanolamines on ductile cast iron using chemical and electrochemical methods was evaluated. This work attempts to clarify the synergistic effect of nitrite and ethanolamines. The effects of single addition of TEA, DEA, and MEA, and mixed addition of nitrite plus TEA, DEA or MEA on the corrosion inhibition of ductile cast iron in a tap water were evaluated. A huge amount of single addition of ethanolamine was needed. However, the synergistic effect by mixed addition was observed regardless of the combination of nitrite and triethanolamines, but their effects increased in a series of MEA + nitrite > DEA + nitrite > TEA + nitrite. This tendency of synergistic effect was attributed to the film properties and polar effect; TEA addition couldn't form the film showing high film resistance and semiconductive properties, but DEA or MEA could build the film having relatively high film resistance and n-type semiconductive properties. Moreover, it can be explained that this behaviour was closely related to electron attractive group within the ethanolamines, and thus corrosion inhibition power depends upon the number of the electron attractive group of MEA, DEA, and TEA.
Effect of Ethanolamines on Corrosion Inhibition of Ductile Cast Iron in Nitrite Containing Solutions

Energy Technology Data Exchange (ETDEWEB)

Kim, K. T.; Kim, Y. S. [Andong National University, Andong (Korea, Republic of); Chang, H. Y.; Lim, B. T.; Park, H. B. [KEPCO Engineering and Construction Company, Gimcheon (Korea, Republic of)

2016-08-15

In this work, synergistic corrosion inhibition effect of nitrite and 3 kinds of ethanolamines on ductile cast iron using chemical and electrochemical methods was evaluated. This work attempts to clarify the synergistic effect of nitrite and ethanolamines. The effects of single addition of TEA, DEA, and MEA, and mixed addition of nitrite plus TEA, DEA or MEA on the corrosion inhibition of ductile cast iron in a tap water were evaluated. A huge amount of single addition of ethanolamine was needed. However, the synergistic effect by mixed addition was observed regardless of the combination of nitrite and triethanolamines, but their effects increased in a series of MEA + nitrite > DEA + nitrite > TEA + nitrite. This tendency of synergistic effect was attributed to the film properties and polar effect; TEA addition couldn't form the film showing high film resistance and semiconductive properties, but DEA or MEA could build the film having relatively high film resistance and n-type semiconductive properties. Moreover, it can be explained that this behaviour was closely related to electron attractive group within the ethanolamines, and thus corrosion inhibition power depends upon the number of the electron attractive group of MEA, DEA, and TEA.
Low-Concentration Indium Doping in Solution-Processed Zinc Oxide Films for Thin-Film Transistors

Directory of Open Access Journals (Sweden)

Xue Zhang

2017-07-01

Full Text Available We investigated the influence of low-concentration indium (In doping on the chemical and structural properties of solution-processed zinc oxide (ZnO films and the electrical characteristics of bottom-gate/top-contact In-doped ZnO thin-film transistors (TFTs. The thermogravimetry and differential scanning calorimetry analysis results showed that thermal annealing at 400 °C for 40 min produces In-doped ZnO films. As the In content of ZnO films was increased from 1% to 9%, the metal-oxygen bonding increased from 5.56% to 71.33%, while the metal-hydroxyl bonding decreased from 72.03% to 9.63%. The X-ray diffraction peaks and field-emission scanning microscope images of the ZnO films with different In concentrations revealed a better crystalline quality and reduced grain size of the solution-processed ZnO thin films. The thickness of the In-doped ZnO films also increased when the In content was increased up to 5%; however, the thickness decreased on further increasing the In content. The field-effect mobility and on/off current ratio of In-doped ZnO TFTs were notably affected by any change in the In concentration. Considering the overall TFT performance, the optimal In doping concentration in the solution-processed ZnO semiconductor was determined to be 5% in this study. These results suggest that low-concentration In incorporation is crucial for modulating the morphological characteristics of solution-processed ZnO thin films and the TFT performance.
Casting Technology.

Science.gov (United States)

Wright, Michael D.; And Others

1992-01-01

Three articles discuss (1) casting technology as it relates to industry, with comparisons of shell casting, shell molding, and die casting; (2) evaporative pattern casting for metals; and (3) high technological casting with silicone rubber. (JOW)
DOE applied to study the effect of process parameters on silicon spacing in lost foam Al-Si-Cu alloy casting

International Nuclear Information System (INIS)

Shayganpour, A; Izman, S; Idris, M H; Jafari, H

2012-01-01

Lost foam casting as a relatively new manufacturing process is extensively employed to produce sound complicated castings. In this study, an experimental investigation on lost foam casting of an Al-Si-Cu aluminium cast alloy was conducted. The research was aimed in evaluating the effect of different pouring temperatures, slurry viscosities, vibration durations and sand grain sizes on eutectic silicon spacing of thin-wall castings. A stepped-pattern was used in the study and the focus of the investigations was at the thinnest 3 mm section. A full two-level factorial design experimental technique was used to plan the experiments and afterwards identify the significant factors affecting casting silicon spacing. The results showed that pouring temperature and its interaction with vibration time have pronounced effect on eutectic silicon phase size. Increasing pouring temperature coarsened the eutectic silicon spacing while the higher vibration time diminished coarsening effect. Moreover, no significant effects on silicon spacing were found with variation of sand size and slurry viscosity.
Characterization of MHPPV films by atomic force and Brewster angle microscopy

International Nuclear Information System (INIS)

Mello, S.V.; Bianchi, R.F.; Balogh, D.T.; Oliveira Junior, O.N.; Faria, R.M.

1999-01-01

We report on the characterization of MHPPV film morphology using Atomic Force Microscopy (AFM) and Brewster Angle Microscopy (BAM) with films deposited by spin coating and casting onto solid substrates such as glass, glass/indium tin oxide (ITO) and quartz. MH-PPV was synthesized according to standard routes, and its properties - obtained from UV-vis. Fourier Transform infrared and Nuclear Magnetic resonance spectroscopy, and high performance size exclusion chromatography - are essentially the same as reported in the literature. From BAM images no significant difference could be observed when comparing cast and spin coated films, since all samples appeared homogeneous under the conditions adopted. Major differences, however, were observed by AFM in the contact mode, especially in roughness values. For a range of temperatures, from 22 deg C up to the transition glass temperature (Tg) of the polymer (ca. 160 deg C), the mean roughness lied in the range 3-5 nm for spin coated films, while for cast films it was 4-10 nm. Samples treated at temperatures above 100 deg C appeared more compact and in all cases the film appeared soft to some extend, which could be the result of the conditions employed. (author)
Modelling of Filling, Microstructure Formation, Local Mechanical Properties and Stress – Strain Development in High-Pressure Die Cast Aluminium Castings

DEFF Research Database (Denmark)

Kotas, Petr; Hattel, Jesper Henri; Thorborg, Jesper

2009-01-01

.e. whether the casting is based on cast iron- or aluminium-alloys. The distribution of local properties in a casting might vary substantially which makes it complex to optimize the casting with good accuracy. Often, mechanical simulations of the load situation are based on the assumption that the cast...... in an aluminium alloy is considered including simulation of the entire casting process with emphasis on microstructure formation related to mechanical properties such as elastic modulus, yield stress, ultimate strength and elongation as well as residual stresses. Subsequently, the casting is subjected to service...... loads and the results of this analysis are discussed in relation to the predicted local properties as well as the residual stresses originating from the casting simulation....
Preparation of enhanced hydrophobic poly(L-lactide-co-ε-caprolactone) films surface and its blood compatibility

Energy Technology Data Exchange (ETDEWEB)

Kim, Seung Il; Lim, Jin Ik; Jung, Youngmee; Mun, Cho Hay [Division of Life and Health Science, Biomaterials Research Center, Korea Institute of Science and Technology, Seoul (Korea, Republic of); Kim, Ji Heung, E-mail: kimjh@skku.edu [Department of Chemical Engineering, Polymer Technology Institute, Sungkyunkwan University, Suwon, Kyunggi (Korea, Republic of); Kim, Soo Hyun, E-mail: soohkim@kist.re.kr [Division of Life and Health Science, Biomaterials Research Center, Korea Institute of Science and Technology, Seoul (Korea, Republic of); KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul (Korea, Republic of)

2013-07-01

Hydrophobicity-enhanced poly(L-lactide-co-ε-caprolactone) (PLCL) (50:50) films were cast by using the solvent–nonsolvent casting method. PLCL (50:50) was synthesized by the well-known random copolymerization process and confirmed by {sup 1}H NMR analysis. The molecular weight of the synthesized PLCL was measured by gel permeation chromatography (GPC). Number-average (Mn), weight-average (Mw) molecular weights and polydispersity (Mw/Mn) were 7 × 10{sup 4}, 1.2 × 10{sup 5}, and 1.7, respectively. PLCL films were cast in vacuum condition with various nonsolvents and nonsolvent ratios. Tetrahydrofuran (THF) was used as the solvent and three different alcohols were used as the nonsolvent: methanol, ethanol, and isopropyl alcohol (IPA). Surface hydrophobicity was confirmed by water contact angle. The water contact angle was increased from 81° ± 2° to 107° ± 2°. Water contact angle was influenced by surface porosity and topography. The prepared film surfaces were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The change of crystalline property was characterized by X-ray diffraction (XRD). Platelet adhesion tests on the modified PLCL film surfaces were evaluated by platelet-rich plasma (PRP). The modified film surface exhibited enhanced hydrophobicity and reduced platelet adhesion ratio depending on the surface topography. One of the candidate products proposed as a potential blood compatible material showed a markedly reduced platelet adhesion property.
Assessment Method of Overheating Degree of a Spent Moulding Sand with Organic Binder, After the Casting Process

Directory of Open Access Journals (Sweden)

Dańko R.

2013-06-01

Full Text Available A proper management of sand grains of moulding sands requires knowing basic properties of the spent matrix after casting knocking out. This information is essential from the point of view of the proper performing the matrix recycling process and preparing moulding sands with reclaimed materials. The most important parameter informing on the matrix quality - in case of moulding sands with organic binders after casting knocking out - is their ignition loss. The methodology of estimating ignition loss of spent moulding sands with organic binder - after casting knocking out - developed in AGH, is presented in the paper. This method applies the simulation MAGMA software, allowing to determine this moulding sand parameter already at the stage of the production preparation.
Influence of film structure on the dewetting kinetics of thin polymer films in the solvent annealing process.

Science.gov (United States)

Zhang, Huanhuan; Xu, Lin; Lai, Yuqing; Shi, Tongfei

2016-06-28

On a non-wetting solid substrate, the solvent annealing process of a thin polymer film includes the swelling process and the dewetting process. Owing to difficulties in the in situ analysis of the two processes simultaneously, a quantitative study on the solvent annealing process of thin polymer films on the non-wetting solid substrate is extremely rare. In this paper, we design an experimental method by combining spectroscopic ellipsometry with optical microscopy to achieve the simultaneous in situ study. Using this method, we investigate the influence of the structure of swollen film on its dewetting kinetics during the solvent annealing process. The results show that for a thin PS film with low Mw (Mw = 4.1 kg mol(-1)), acetone molecules can form an ultrathin enriched layer between the PS film and the solid substrate during the swelling process. The presence of the acetone enriched layer accounts for the exponential kinetic behavior in the case of a thin PS film with low Mw. However, the acetone enriched layer is not observed in the case of a thin PS film with high Mw (Mw = 400 kg mol(-1)) and the slippage effect of polymer chains is valid during the dewetting process.
Submerged process of bio films; Procesos sumergidos de biopelicula

Energy Technology Data Exchange (ETDEWEB)

Hontoria, E.; Zamorano, M.; Gomez, M.A.; Gonzalez, J. [Departamento de Ingeneria Civil, Universidad de Granada (Spain)

1995-07-01

The bio film process is the most frequently used one for the water treatment. This article presents the advantages of the bio film process, and its conclusion is: the increase of bio film takes place in 9 days, the appearance of nitrites and the small importance of feeding coefficients for the temperature of water.
Die casting copper motor rotors: mold materials and processing for cost-effective manufacturing

Energy Technology Data Exchange (ETDEWEB)

Peters, D.T.; Cowie, J.G.; Brush, E.F. Jr.

2000-07-01

This project seeks to demonstrate mold materials for copper pressure die-casting that are cost-effective and practical for production use in die-casting copper motor rotors. The incorporation of die-cast copper for conductor bars and end rings of the induction motor in place of aluminum would result in attractive improvements in motor energy efficiency through reductions in motor losses ranging from 15% to 20%. Die-cast motor rotors are produced in aluminum today because rotor fabrication by pressure die-casting is an established practice. Lack of a durable and cost-effective mold material has been the technical barrier preventing manufacture of the die-cast copper rotor. This project tested H-13 steel die inserts that establish the baseline. Nickel-, tungsten-, and molybdenum-based high temperature alloys were extensively tested. Results indicate that substantially extended die life is possible using high temperature die materials, pre-heated and operated at elevated temperatures. Pre-heating and high operating temperatures were shown to be critical in extending the die life by decreasing the cyclic stresses associated with thermal expansion. Extended die life provides the opportunity for economically viable copper motor rotor die-casting. (orig.)
Fabrication and mechanical characterization of biodegradable and synthetic polymeric films: Effect of gamma radiation

International Nuclear Information System (INIS)

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

2012-01-01

Chitosan (1 wt%, in 2% aqueous acetic acid solution) and starch (1 wt%, in deionised water) were dissolved and mixed in different proportions (20–80 wt% chitosan) then films were prepared by casting. Tensile strength and elongation at break of the 50% chitosan containing starch-based films were found to be 47 MPa and 16%, respectively. It was revealed that with the increase of chitosan in starch, the values of TS improved significantly. Monomer, 2-butane diol-diacrylate (BDDA) was added into the film forming solutions (50% starch-based), then casted films. The BDDA containing films were irradiated under gamma radiation (5–25 kGy) and it was found that strength of the films improved significantly. On the other hand, synthetic petroleum-based polymeric films (polycaprolactone, polyethylene and polypropylene) were prepared by compression moulding. Mechanical and barrier properties of the films were evaluated. The gamma irradiated (25 kGy) films showed higher strength and better barrier properties. - Highlights: ► Chitosan and starch-based biodegradable films were prepared by casting. ► With the increase of chitosan in starch, the strength of the films improved significantly. ► Monomer, 2-Butane diol-diacrylate was grafted with the films by gamma radiation. ► Mechanical properties of synthetic polymeric films improved by gamma radiation. ► The irradiated polymer films showed better water vapor barrier properties.
Impact of as-cast structure on structure and properties of twin-roll cast AA8006 alloy

Energy Technology Data Exchange (ETDEWEB)

Slamova, M.; Ocenasek, V. [Vyzkumny Ustav Kovu, Panenske Brezany (Czechoslovakia); Juricek, Z.

2000-07-01

Sheet production by twin-roll casting (TRC) process is a well established practice in the aluminium industry because it offers several advantages in comparison with DC casting and hot rolling, esp. lower production and investment costs. Thin strips exhibiting a combination of good strength and high ductility are required for various applications and for this reason alloys with higher Fe and Mn content such as AA 8006 displace AA 1xxx or AA 8011 alloys. However, TRC of AA 8006 strips involves several problems, e.g. casting conditions and subsequent treatment procedures need fine tuning. The results of an investigation of the effect of casting conditions on structure and properties of AA 8006 strips are presented. The influence of casting speed, grain refiner addition, molten metal level in the tundish, tip setback and roll separating force was investigated. The impact of imperfect as-cast structure on structure and properties of thin strips in H22 and O tempers was evaluated and compared with strips from good as-cast material. (orig.)
Costs Analysis of Iron Casts Manufacturing

Directory of Open Access Journals (Sweden)

S. Kukla

2012-04-01

Full Text Available The article presents the issues of costs analysis of iron casts manufacturing using automated foundry lines. Particular attention was paid to departmental costs, conversion costs and costs of in-plant transport. After the Pareto analysis had been carried out, it was possible to set the model area of the process and focus on improving activities related to finishing of a chosen group of casts. In order to eliminate losses, the activities realised in this domain were divided into activities with added value, activities with partially added value and activities without added value. To streamline the production flow, it was proposed to change the location of workstations related to grinding, control and machining of casts. Within the process of constant improvement of manufacturing processes, the aspect of work ergonomics at a workstation was taken into account. As a result of the undertaken actions, some activities without added value were eliminated, efficiency was increased and prime costs of manufacturing casts with regard to finishing treatment were lowered.
Workplace Basic Skills in the Metal Casting Industry for World Class Process and Technology.

Science.gov (United States)

Rasmussen, Bonnie

A workplace basic skills project for the metal casting industry was established jointly by Central Alabama Community College and Robinson Foundry, Inc. Evaluation of the project was made through a commercial test of hourly workers' general literacy level gains, instructor-developed pre- and posttests of mastery of the industrial process and…
Precision casting into disposable ceramic mold – a high efficiency method of production of castings of irregular shape

OpenAIRE

Уваров, Б. И.; Лущик, П. Е.; Андриц, А. А.; Долгий, Л. П.; Заблоцкий, А. В.

2016-01-01

The article shows the advantages and disadvantages of precision casting into disposable ceramic molds. The high quality shaped castings produced by modernized ceramic molding process are proved the reliability and prospects of this advanced technology.
A new casting defect healing technology

Energy Technology Data Exchange (ETDEWEB)

Hodge, E.S.; Reddoch, T.W. [ForMat Industries, Inc., Knoxville, TN (United States); Viswanathan, S. [Oak Ridge National Lab., TN (United States)

1997-01-01

A new technology is presented for healing of defects in 356 aluminium alloys that provides economic upgrading of these cast alloys. It uses pneumatic isostatic forging (PIF) to produce high quality Al alloys products with enhanced mechanical properties uniform throughout the part, allowing higher design allowables and increased usage of Al alloy castings. The fundamental mechanism underlying PIF is a single mode plastic deformation process that uses isostatic application of pressures for 10-30 seconds at temperature. The process can be integrated in-line with other production operations, i.e., using the latent heat from the previous casting step. Results of applying the PIF process indicate lower cost and significant improvement in mechanical properties that rival and often exceed corresponding properties of other technologies like hot isostatic pressing and related processes. This process offers many advantages that are described in this paper in addition to presenting case histories of property enhancement by PIF and the mechanism responsible for property enhancement.

Solidification and casting

CERN Document Server

Cantor, Brian

2002-01-01

INDUSTRIAL PERSPECTIVEDirect chillcasting of aluminium alloysContinuous casting of aluminium alloysContinuous casting of steelsCastings in the automotive industryCast aluminium-silicon piston alloysMODELLING AND SIMULATIONModelling direct chill castingMold filling simulation of die castingThe ten casting rulesGrain selection in single crystal superalloy castingsDefects in aluminium shape castingPattern formation during solidificationPeritectic solidificationSTRUCTURE AND DEFECTSHetergeneous nucleation in aluminium alloysCo
Temperature and microstructure characteristics of silumin casting AlSi9 made with investment casting method

Directory of Open Access Journals (Sweden)

S. Pietrowski

2011-07-01

Full Text Available This work presents the research result of the temperature distribution and the microstructure in certain parts of the field-glass body frame casting made from silumin AlSi9 using the investment casting method in the ceramic mould. It was proved that the highest temperature of the silumin appears in the sprue in which the silumin is in the liquid-solid state, though the process of silumin crystallization in the casting is finished. It was stated that in certain elements of the casting the side opposite to the runner crystallizes and cools fastest. The differences in the rate of crystalline growth and cooling of certain casting elements cause differ- ent microstructure in them which can also influence the mechanic properties.It is necessary to state that the temperature of the initial heating of the ceramic mold equal to 60oC guarantees obtaining of the castings without defects and of little porosity. Incomplete modification of the silumin with strontium causes silica precipitation to appear close to the spherical ones.
Fabrication of compact and stable perovskite films with optimized precursor composition in the fast-growing procedure

Energy Technology Data Exchange (ETDEWEB)

Liu, Tanghao; Zhou, Yuanyuan; Hu, Qin; Chen, Ke; Zhang, Yifei; Yang, Wenqiang; Wu, Jiang; Ye, Fengjun; Luo, Deying; Zhu, Kai; Padture, Nitin P.; Liu, Feng; Russell, Thomas; Zhu, Rui; Gong, Qihuang

2017-06-02

The fast-growing procedure (FGP) provides a simple, high-yield and lead (Pb)-release free method to prepare perovskite films. In the FGP, the ultra-dilute perovskite precursor solution is drop-cast onto a hot (~240 degrees C) substrate, where a perovskite film grows immediately accompanied by the rapid evaporation of the host solvent. In this process, all the raw materials in the precursor solution are deposited into the final perovskite film. The potential pollution caused by Pb can be significantly reduced. Properties of the FGP-processed perovskite films can be modulated by the precursor composition. While CH3NH3Cl (MACl) affects the crystallization process and leads to full surface coverage, CH(NH2)2I (FAI) enhances the thermal stability of the film. Based on the optimized precursor composition of PbI2(1-x)FAI xMACl, x=0.75, FGP-processed planar heterojunction perovskite solar cells exhibit power conversion efficiencies (PCEs) exceeding 15% with suppressed hysteresis and excellent reproducibility.
Thermoplastic processing of proteins for film formation--a review.

Science.gov (United States)

Hernandez-Izquierdo, V M; Krochta, J M

2008-03-01

Increasing interest in high-quality food products with increased shelf life and reduced environmental impact has encouraged the study and development of edible and/or biodegradable polymer films and coatings. Edible films provide the opportunity to effectively control mass transfer among different components in a food or between the food and its surrounding environment. The diversity of proteins that results from an almost limitless number of side-chain amino-acid sequential arrangements allows for a wide range of interactions and chemical reactions to take place as proteins denature and cross-link during heat processing. Proteins such as wheat gluten, corn zein, soy protein, myofibrillar proteins, and whey proteins have been successfully formed into films using thermoplastic processes such as compression molding and extrusion. Thermoplastic processing can result in a highly efficient manufacturing method with commercial potential for large-scale production of edible films due to the low moisture levels, high temperatures, and short times used. Addition of water, glycerol, sorbitol, sucrose, and other plasticizers allows the proteins to undergo the glass transition and facilitates deformation and processability without thermal degradation. Target film variables, important in predicting biopackage performance under various conditions, include mechanical, thermal, barrier, and microstructural properties. Comparisons of film properties should be made with care since results depend on parameters such as film-forming materials, film formulation, fabrication method, operating conditions, testing equipment, and testing conditions. Film applications include their use as wraps, pouches, bags, casings, and sachets to protect foods, reduce waste, and improve package recyclability.
Monitoring tablet surface roughness during the film coating process

DEFF Research Database (Denmark)

Seitavuopio, Paulus; Heinämäki, Jyrki; Rantanen, Jukka

2006-01-01

The purpose of this study was to evaluate the change of surface roughness and the development of the film during the film coating process using laser profilometer roughness measurements, SEM imaging, and energy dispersive X-ray (EDX) analysis. Surface roughness and texture changes developing during...... the process of film coating tablets were studied by noncontact laser profilometry and scanning electron microscopy (SEM). An EDX analysis was used to monitor the magnesium stearate and titanium dioxide of the tablets. The tablet cores were film coated with aqueous hydroxypropyl methylcellulose, and the film...... coating was performed using an instrumented pilot-scale side-vented drum coater. The SEM images of the film-coated tablets showed that within the first 30 minutes, the surface of the tablet cores was completely covered with a thin film. The magnesium signal that was monitored by SEM-EDX disappeared after...
Bainite obtaining in cast iron with carbides castings

Directory of Open Access Journals (Sweden)

S. Pietrowski

2010-01-01

Full Text Available In these paper the possibility of upper and lower bainite obtaining in cast iron with carbides castings are presented. Conditions, when in cast iron with carbides castings during continuous free air cooling austenite transformation to upper bainite or its mixture with lower bainte proceeds, have been given. A mechanism of this transformation has been given, Si, Ni, Mn and Mo distribution in the eutectic cell has been tested and hardness of tested castings has been determined.
Modeling of microstructure evolution of magnesium alloy during the high pressure die casting process

International Nuclear Information System (INIS)

Wu Mengwu; Xiong Shoumei

2012-01-01

Two important microstructure characteristics of high pressure die cast magnesium alloy are the externally solidified crystals (ESCs) and the fully divorced eutectic which form at the filling stage of the shot sleeve and at the last stage of solidification in the die cavity, respectively. Both of them have a significant influence on the mechanical properties and performance of magnesium alloy die castings. In the present paper, a numerical model based on the cellular automaton (CA) method was developed to simulate the microstructure evolution of magnesium alloy during cold-chamber high pressure die casting (HPDC) process. Modeling of dendritic growth of magnesium alloy with six-fold symmetry was achieved by defining a special neighbourhood configuration and calculating of the growth kinetics from complete solution of the transport equations. Special attention was paid to establish a nucleation model considering both of the nucleation of externally solidified crystals in the shot sleeve and the massive nucleation in the die cavity. Meanwhile, simulation of the formation of fully divorced eutectic was also taken into account in the present CA model. Validation was performed and the capability of the present model was addressed by comparing the simulated results with those obtained by experiments.
Study on Compatibility between Converters and Casting Machines for Daily Steelmaking and Continuous Casting Scheduling

Institute of Scientific and Technical Information of China (English)

MA Feng-cai; ZHANG Qun

2009-01-01

In this paper, daily production scheduling is studied based on the Third Steelmaking Plant of Wuhan Iron and steel corporation (WISCO). To make sure the daily production plan is feasible, method of casting gToup is established, and the compatibility between two converters and three continuous casting devices in the Third Steelmaking Plant of WISCO is analyzed. The process flow chart of daily production scheduling is given in this paper. Then, algorithms and procedures for the simulation of daily production plan is developed. Using the actual data from the Third Steelmaking Plant, the feasible daily steelmaking plan and cast plan are given. The plan contains 7 groups of cast plan, figured out 54 converters, and a- bout 13,500 tons steel.
Comparison of marginal accuracy of castings fabricated by conventional casting technique and accelerated casting technique: an in vitro study.

Science.gov (United States)

Reddy, S Srikanth; Revathi, Kakkirala; Reddy, S Kranthikumar

2013-01-01

Conventional casting technique is time consuming when compared to accelerated casting technique. In this study, marginal accuracy of castings fabricated using accelerated and conventional casting technique was compared. 20 wax patterns were fabricated and the marginal discrepancy between the die and patterns were measured using Optical stereomicroscope. Ten wax patterns were used for Conventional casting and the rest for Accelerated casting. A Nickel-Chromium alloy was used for the casting. The castings were measured for marginal discrepancies and compared. Castings fabricated using Conventional casting technique showed less vertical marginal discrepancy than the castings fabricated by Accelerated casting technique. The values were statistically highly significant. Conventional casting technique produced better marginal accuracy when compared to Accelerated casting. The vertical marginal discrepancy produced by the Accelerated casting technique was well within the maximum clinical tolerance limits. Accelerated casting technique can be used to save lab time to fabricate clinical crowns with acceptable vertical marginal discrepancy.
Study on interfacial heat transfer coefficient at metal/die interface during high pressure die casting process of AZ91D alloy

Directory of Open Access Journals (Sweden)

GUO Zhi-peng

2007-02-01

Full Text Available The high pressure die casting (HPDC process is one of the fastest growing and most efficient methods for the production of complex shape castings of magnesium and aluminum alloys in today’s manufacturing industry.In this study, a high pressure die casting experiment using AZ91D magnesium alloy was conducted, and the temperature profiles inside the die were Measured. By using a computer program based on solving the inverse heat problem, the metal/die interfacial heat transfer coefficient (IHTC was calculated and studied. The results show that the IHTC between the metal and die increases right after the liquid metal is brought into the cavity by the plunger,and decreases as the solidification process of the liquid metal proceeds until the liquid metal is completely solidified,when the IHTC tends to be stable. The interfacial heat transfer coefficient shows different characteristics under different casting wall thicknesses and varies with the change of solidification behavior.
Study on Removal of Bubble on Polyimide Film Surface%聚酰亚胺薄膜表面气泡去除技术研究

Institute of Scientific and Technical Information of China (English)

任小龙; 李雪明; 金城; 南洋; 莫志华

2015-01-01

通过分析气泡、杂质、色差等因素对聚酰亚胺薄膜表观质量的影响，从树脂合成和流涎液膜两过程对气泡去除工艺进行研究，对现有消泡釜及消泡工艺、流涎液膜处理装置及流涎工艺进行改进。结果表明：通过新型消泡釜和新型PAA液膜消泡装置均能有效的消除聚酰亚胺薄膜表面的微小气泡，使聚酰亚胺薄膜产品的色差减小，厚度公差降低，外观质量大幅提高。%Through analyzing the effect of bubble, impurity, and colour difference on the surface quality of polyimide film, we studied the bubble removal technology from resin synthesis and film casting process, and the existing defoaming kettle and defoaming process, casting equipment and casting process were improved. The results show that the micro-bubbles on the polyimide film surface could be removed by the new defoaming kettle and new PAA liquid film, the product’s colour difference and thickness tolerance decrease, and the appearance quality is improved significantly.
Method of producing thin cellulose nitrate film

International Nuclear Information System (INIS)

Lupica, S.B.

1975-01-01

An improved method for forming a thin nitrocellulose film of reproducible thickness is described. The film is a cellulose nitrate film, 10 to 20 microns in thickness, cast from a solution of cellulose nitrate in tetrahydrofuran, said solution containing from 7 to 15 percent, by weight, of dioctyl phthalate, said cellulose nitrate having a nitrogen content of from 10 to 13 percent
Comparison of microstructure and mechanical properties of A356 aluminum alloy/Al2O3 composites fabricated by stir and compo-casting processes

International Nuclear Information System (INIS)

Sajjadi, S.A.; Ezatpour, H.R.; Torabi Parizi, M.

2012-01-01

Highlights: → Nano and micro-composites (A356/Al 2 O 3 ) were fabricated by stir-casting and compo-casting. → Uniform distribution, grain refinement and low porosity in the composites were attained. → Addition of alumina led to the improvement in yield, ultimate tensile and compression strength. → Nano-alumina particles and compo-casting process obtained the best mechanical properties. -- Abstract: Metal-matrix composites (MMCs), as light and strong materials, are very attractive for application in different industries. In the present work, nano and micro-composites (A356/Al 2 O 3 ) with different weight percent of particles were fabricated by two melt techniques such as stir-casting and compo-casting. Microstructural characterization was investigated by optical (OP) and scanning electron microscopy (SEM). Tensile, hardness and compression tests were carried out in order to identify mechanical properties of the composites. The results of microstructural study revealed uniform distribution, grain refinement and low porosity in micro and nano-composite specimens. The mechanical results showed that the addition of alumina (micro and nano) led to the improvement in yield strength, ultimate tensile strength, compression strength and hardness. It was indicated that type of fabrication process and particle size were the effective factors influencing on the mechanical properties. Decreasing alumina particle size and using compo-casting process obtained the best mechanical properties.
Modeling and analysis of film composition on mechanical properties of maize starch based edible films.

Science.gov (United States)

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

2013-11-01

The present study investigates the influence of composition (content of maize starch (1-3 g), sorbitol (0.5-1.0 ml), agar (0.5-1.0 g) and tween-80 (0.1-0.5 ml)) on the mechanical properties (tensile strength, elongation, Young's modulus, puncture force and puncture deformation) of the maize starch based edible films using four factors with three level Box-Behnken design. The edible films were obtained by casting method. The results showed that, tween-80 increases the permeation of sorbitol in to the polymer matrix. Increasing concentration of sorbitol (hydrophilic nature and plasticizing effect of sorbitol) decreases the tensile strength, Young's modulus and puncture force of the films. The results were analyzed by Pareto analysis of variance (ANOVA) and second order polynomial models were obtained for all responses with high R(2) values (R(2)>0.95). 3D response surface plots were constructed to study the relationship between process variables and the responses. Copyright © 2013 Elsevier B.V. All rights reserved.
Limitations of retarded (bisulfite) x-ray film processing

International Nuclear Information System (INIS)

Stoering, J.P.; Dittmore, C.

1979-01-01

We demonstrate the limitations of using retarded (bisulfite) developer to abate film sensitivity of x-ray films that have been exposed to intense radiation. We compared the measured densities of a large number of Kodak Type-M x-ray film samples exposed to a known fluence of monochromatic x-rays. These film samples were processed in three separate batches of bisulfite developer mixed in the same proportions. We concluded that reproducible film-density information cannot be obtained using different batches of (bisulfite) developer solutions
Ordering process of sputtered FePt films

International Nuclear Information System (INIS)

Takahashi, Y.K.; Ohnuma, M.; Hono, K.

2003-01-01

We have investigated the in situ ordering process of sputtered FePt thin films deposited on heated substrates at 300 deg. C with different thicknesses. The films thinner than 50 nm were composed of nanograins (∼5 nm) of disordered FePt phase. Recrystallization occurred when films were grown thicker than 100 nm, and transformation twins were observed in recrystallized grains, in which ordering to the L1 0 structure was confirmed
Effect of heating cast kafirin films on their functional properties

CSIR Research Space (South Africa)

Byaruhanga, YB

2007-01-01

Full Text Available of heated plasticized films showed more wrinkled structures compared to non-heated films, whereas the non-plasticized films appeared more brittle with heating. The results indicate that heat-induced intermolecular disulfide cross-linking was involved...
Influence of additives on melt viscosity, surface tension, and film formation of dry powder coatings.

Science.gov (United States)

Sauer, Dorothea; McGinity, James W

2009-06-01

Limited information on thermally cured dry-powder coatings used for solid dosage forms has been available in the literature. The aim of this study was to characterize the film formation process of Eudragit L 100-55 dry-powder coatings and to investigate the influence of film additives on melt viscosity and surface tension. The coating process employed no liquids and the plasticizer was combined with the polymer using hot melt extrusion. Thermoanalytical methods including differential scanning calorimetry and thermogravimetric analysis (TGA) were used to investigate the thermal properties of the dry-coating formulations. The rheological behavior of the coating formulations were characterized with the extrusion torque, and the surface energy parameters were determined from contact angle measurements. The influence of the level of triethyl citrate (TEC) as plasticizer and polyethylene glycol (PEG) 3350 in the polymer film on film formation was investigated using a digital force tester. TGA confirmed thermal stability of all coating excipients at the investigated curing conditions. Increasing TEC levels and the addition of PEG 3350 as a low melting excipient in the coating reduced the viscosity of the polymer. Plasticization of the polymer with TEC increased the surface free energy, whereas the admixture of 10% PEG 3350 did not affect the surface free energy of Eudragit L 100-55. The spreading coefficient of the polymers over two sample tablet formulations was reduced with increasing surface free energy. During the curing process, puncture strength, and elongation of powder-cast films increased. The effect of curing time on the mechanical properties was dependent on the plasticizer content. The incorporation of TEC and PEG 3350 into the Eudragit L 100-55 powder coating formulation improved film formation. Mechanical testing of powder-cast films showed an increase of both elongation and puncture strength over the curing process as criterion for polymer particle fusion
PRECISION CASTING INTO DISPOSABLE CERAMIC MOLD – A HIGH EFFICIENCY METHOD OF PRODUCTION OF CASTINGS OF IRREGULAR SHAPE

Directory of Open Access Journals (Sweden)

B. I. Uvarov

2016-01-01

Full Text Available The article shows the advantages and disadvantages of precision casting into disposable ceramic molds. The high quality shaped castings produced by modernized ceramic molding process are proved the reliability and prospects of this advanced technology.
PRODUCTION OF ROTARY ENGINES’ PARTS FROM ALUMINUM ALLOYS USING LOST FOAM CASTING PROCESS

Directory of Open Access Journals (Sweden)

E. I. Marukovich

2018-01-01

Full Text Available The production technology of casting details for rotary engine from the aluminum alloy АК12М2 is developed. The bulk density of expanded polystyrene to ensure the best quality of the surface of castings has been experimentally established. The lost foam casting shop was organized in the experimental department of the Institute.

Temperature field in the hot-top during casting a new super-high strength Al-Zn-Mg-Cu alloy by low frequency electromagnetic process

Directory of Open Access Journals (Sweden)

Yubo ZUO

2005-08-01

Full Text Available The billets of a new super-high strength Al-Zn-Mg-Cu alloy in 200 mm diameter were produced by the processed of low frequency electromagnetic casting (LFEC and conventional direct chill(DCcasting, respectively. The effects of low frequency electromagnetic field on temperature field of the melt in the hot-top were investigated by temperature thermocouples into the casting during the processes. The results show that during LFEC process the temperature field in the melt applying the hot-top is very uniform, which is helpful to reduce the difference of thermal gradients between the surface and the center, and then to reduce the thermal stress and to eliminate casting crack.
Enhancement of polar crystalline phase formation in transparent PVDF-CaF{sub 2} composite films

Energy Technology Data Exchange (ETDEWEB)

Lee, Sang Goo; Ha, Jong-Wook, E-mail: jongwook@krict.re.kr; Sohn, Eun-Ho; Park, In Jun; Lee, Soo-Bok

2016-12-30

Highlights: • The crystalline phase in transparent PVDF-CaF{sub 2} composite films was investigated. • CaF{sub 2} promoted the formation of polar crystalline phases in PVDF matrix. • Ordered γ-phase was obtained by thermal treatment of as-cast films at the vicinity of its melting temperature. - Abstract: We consider the influence of calcium fluoride (CaF{sub 2}) nanoparticles on the crystalline phase formation of poly(vinylidene fluoride) (PVDF) for the first time. The transparent PVDF-CaF{sub 2} composite films were prepared by casting on PET substrates using N,N-dimethylacetamide (DMAc) as a solvent. It was found that CaF{sub 2} promoted the formation of polar crystalline phase of PVDF in composites, whereas nonpolar α-phase was dominant in the neat PVDF film prepared at the same condition. The portion of polar crystalline phase increased in proportional to the weight fraction of CaF{sub 2} in the composite films up to 10 wt%. Further addition of CaF{sub 2} suppressed completely the α-phase formation. Polar crystalline phase observed in as-cast composite films was a mixture of β- and γ-polymorph structures. It was also shown that much ordered γ-phase could be obtained through thermal treatment of as-cast PVDF-CaF{sub 2} composite film at the temperatures above the melting temperature of the composite films, but below that of γ-phase.
Development of casting techniques for uranium and uranium alloys

International Nuclear Information System (INIS)

Singh, S.P.

2003-01-01

The casting process concerning furnace set-up, mould temperatures, pouring temperatures, out gassing, post heating, casting recovery and crucible and mould clean-up is discussed. Some applications of casting theory can be made in practice, but experience in handling the metal is most valuable in the successful solution of a new problem. The casting of uranium alloys using induction stirring of the melt to promote homogeneity in the casting is described. A few remarks are made concerning safety aspects associated with the casting of uranium
Report of Separate Effects Testing for Modeling of Metallic Fuel Casting Process

Energy Technology Data Exchange (ETDEWEB)

Crapps, Justin M. [Los Alamos National Laboratory; Galloway, Jack D. [Los Alamos National Laboratory; Decroix, David S. [Los Alamos National Laboratory; Korzekwa, David A. [Los Alamos National Laboratory; Aikin, Robert M. Jr. [Los Alamos National Laboratory; Unal, Cetin [Los Alamos National Laboratory; Fielding, R. [Idaho National Laboratory; Kennedy, R [Idaho National Laboratory

2012-06-29

In order to give guidance regarding the best investment of time and effort in experimental determination of parameters defining the casting process, a Flow-3D model of the casting process was used to investigate the most influential parameters regarding void fraction of the solidified rods and solidification speed for fluid flow parameters, liquid heat transfer parameters, and solid heat transfer parameters. Table 1 summarizes the most significant variables for each of the situations studied. A primary, secondary, and tertiary effect is provided for fluid flow parameters (impacts void fraction) and liquid heat transfer parameters (impacts solidification). In Table 1, the wetting angle represents the angle between the liquid and mold surface as pictured in Figure 1. The viscosity is the dynamic viscosity of the liquid and the surface tension is the property of the surface of a liquid that allows it to resist an external force. When only considering solid heat transfer properties, the variations from case to case were very small. Details on this conclusion are provided in the section considering solid heat transfer properties. The primary recommendation of the study is to measure the fluid flow parameters, specifically the wetting angle, surface tension, and dynamic viscosity, in order of importance, as well as the heat transfer parameters latent heat and specific heat of the liquid alloy. The wetting angle and surface tension can be measured simultaneously using the sessile drop method. It is unclear whether there is a temperature dependency in these properties. Thus measurements for all three parameters are requested at 1340, 1420, and 1500 degrees Celsius, which correspond to the minimum, middle, and maximum temperatures of the liquid alloy during the process. In addition, the heat transfer coefficient between the mold and liquid metal, the latent heat of transformation, and the specific heat of the liquid metal all have strong influences on solidification. These
Transparent Low Electrostatic Charge Films Based on Carbon Nanotubes and Polypropylene. Homopolymer Cast Films

Directory of Open Access Journals (Sweden)

Zoe Vineth Quiñones-Jurado

2018-01-01

Full Text Available Use of multi-wall carbon nanotubes (MWCNTs in external layers (A-layers of ABA-trilayer polypropylene films was investigated, with the purpose of determining intrinsic and extrinsic factors that could lead to antistatic behavior of transparent films. The incorporation of 0.01, 0.1, and 1 wt % of MWCTNs in the A-layers was done by dilution through the masterbatch method. Masterbatches were fabricated using isotactic polypropylene (iPP with different melt flow indexes 2.5, 34, and 1200 g/10 min, and using different ultrasound assist methods. It was found that films containing MWCNTs show surface electrical resistivity of 1012 and 1016 Ω/sq, regardless of the iPP melt flow index (MFI and masterbatch fabrication method. However, electrostatic charge was found to depend upon the iPP MFI, the ultrasound assist method and MWCNT concentration. A percolation electron transport mechanism was determined most likely responsible for this behavior. Optical properties for films containing MWCNTs do not show significant differences compared to the reference film at MWCNT concentrations below 0.1 wt %. However, an enhancement in brightness was observed, and it was attributed to ordered iPP molecules wrapping the MWCNTs. Bright transparent films with low electrostatic charge were obtained even for MWCNTs concentrations as low as 0.01 wt %.
Surface Modification of Solution-Processed ZrO2 Films through Double Coating for Pentacene Thin-Film Transistors

Science.gov (United States)

Kwon, Jin-Hyuk; Bae, Jin-Hyuk; Lee, Hyeonju; Park, Jaehoon

2018-03-01

We report the modification of surface properties of solution-processed zirconium oxide (ZrO2) dielectric films achieved by using double-coating process. It is proven that the surface properties of the ZrO2 film are modified through the double-coating process; the surface roughness decreases and the surface energy increases. The present surface modification of the ZrO2 film contributes to an increase in grain size of the pentacene film, thereby increasing the field-effect mobility and decreasing the threshold voltage of the pentacene thin-film transistors (TFTs) having the ZrO2 gate dielectric. Herein, the molecular orientation of pentacene film is also studied based on the results of contact angle and X-ray diffraction measurements. Pentacene molecules on the double-coated ZrO2 film are found to be more tilted than those on the single-coated ZrO2 film, which is attributed to the surface modification of the ZrO2 film. However, no significant differences are observed in insulating properties between the single-and the double-coated ZrO2 dielectric films. Consequently, the characteristic improvements of the pentacene TFTs with the double-coated ZrO2 gate dielectric film can be understood through the increase in pentacene grain size and the reduction in grain boundary density.
Investment casting of beta titanium alloys for aerospace applications

International Nuclear Information System (INIS)

Wheeler, D.A.; Cianci, M.S.; Vogt, R.G.

1993-01-01

The process of investment casting offers the ability to produce complex titanium components with minimal finish machining, thereby reducing their overall manufacturing cost. While aerospace applications for cast titanium have focused primarily on alpha+beta alloys, recent interest in higher strength beta alloys has prompted an examination of their suitability for investment casting. In this paper, the processing characteristics and mechanical proper-ties of Ti-1 5V-3Cr-3Al-3Sn, Ti-3Al-8V-6Cr-4Mo-4Zr, and Ti-15Mo-3Nb-3Al-0.2Si (wt.%) will be discussed. It will be shown that all three alloy compositions are readily processed using only slight modifications from current Ti-6Al-4V (wt.%) production operations. In addition, the mechanical properties of the cast product form can be manipulated through heat treatment and compare quite favorably with typical properties obtained in wrought beta titanium products. Finally, several demonstration castings are reviewed which illustrate the shape-making capabilities of the investment casting approach for beta titanium alloys
The effect of cast-to-cast variations on the quality of thin section nickel alloy welded joints

International Nuclear Information System (INIS)

Lambert, J.A.

1989-02-01

The welding behaviour of 26 commercial casts of Alloy 800 has been quantified for mechanised, autogenous, full penetration, bead-on-strip tungsten inert gas welding tests. Weld front and back widths have been measured and correlated with minor element variations. Casts with similar welding responses have been sorted into groups. The behaviour of the weld pool, surface slags and arc have been compared and a convection controlled model has been used to account for differences between the groups of casts. The main factors governing laboratory process control variability have been identified and a statistical method has been used to identify all the components of weld variance. An optimum size of welding test matrix has been proposed to determine typical cast-to-cast variations at high significance levels. (author)
Microstructured metal molds fabricated via investment casting

International Nuclear Information System (INIS)

Cannon, Andrew H; King, William P

2010-01-01

This paper describes an investment casting process to produce aluminum molds having integrated microstructures. Unlike conventional micromolding tools, the aluminum mold was large and had complex curved surfaces. The aluminum was cast from curved microstructured ceramic molds which were themselves cast from curved microstructured rubber. The aluminum microstructures had an aspect ratio of 1:1 and sizes ranging from 25 to 50 µm. Many structures were successfully cast into the aluminum with excellent replication fidelity, including circular, square and triangular holes. We demonstrate molding of large, curved surfaces having surface microstructures using the aluminum mold.
Semi-solid twin-roll casting process of magnesium alloy sheets

International Nuclear Information System (INIS)

Watari, H.; Davey, K.; Rasgado, M.T. Alonso; Haga, T.; Koga, N.

2004-01-01

An experimental approach has been performed to ascertain the effectiveness of semi-solid strip casting using a horizontal twin roll caster. The demand for light-weight products with high strength has grown recently due to the rapid development of automobile and aircraft technology. One key to such development has been utilization of magnesium alloys, which can potentially reduce the total product weight. However, the problems of utilizing magnesium alloys are still mainly related to high manufacturing cost. One of the solutions to this problem is to develop magnesium casting-rolling technology in order to produce magnesium sheet products at competitive cost for commercial applications. In this experiment, magnesium alloy AZ31B was used to ascertain the effectiveness of semi-solid roll strip casting for producing magnesium alloy sheets. The temperature of the molten magnesium, and the roll speeds of the upper and lower rolls, (which could be changed independently), were varied to find an appropriate manufacturing condition. Rolling and heat treatment conditions were changed to examine which condition would be appropriate for producing wrought magnesium alloys with good formability. Microscopic observation of the crystals of the manufactured wrought magnesium alloys was performed. It has been found that a limiting drawing ratio of 2.7 was possible in a warm deep drawing test of the cast magnesium alloy sheets after being hot rolled
Physical Properties and Antibacterial Efficacy of Biodegradable Chitosan Films

OpenAIRE

中島, 照夫

2009-01-01

[Synopsis] Chitin, chitosan and quaternary chitosan films were prepared, and the physical properties and the antibacterial activities of chitosan and quaternary chitosan films were evaluated. The tensile strength of chitin films was 30～40％ lower than that of chitosan films, but the crystallinity of chitin film was much higher than that of chitosan films. The crystallinity and orientation of crystallites were hardly affected by the four kinds of solvent chosen to cast chitosan films, but a de...
Morphology and Precipitation Kinetics of MnS in Low-Carbon Steel During Thin Slab Continuous Casting Process

Institute of Scientific and Technical Information of China (English)

YU Hao; KANG Yong-lin; ZHAO Zheng-zhi; SUN Hao

2006-01-01

The morphology of manganese sulfide formed during thin slab continuous casting process in low-carbon steel produced by compact strip production (CSP) technique was investigated. Using transmission electron microscopy analysis, it was seen that a majority of manganese sulfides precipitated at austenite grain boundaries, the morphologies of which were spherical or close to the spherical shape and the size of MnS precipitates ranged from 30 nm to 100 nm. A mathematical model of the manganese sulfide precipitation in this process was developed based on classical nucleation theory. Under the given conditions, the starting and finishing precipitation temperatures of MnS in the continuous casting thin slab of the studied low-carbon steel are 1 189 ℃ and 1 171 ℃, respectively, and the average diameter of MnS precipitates is about 48 nm within this precipitation temperature range. The influences of chemical components and thermo-mechanical processing conditions on the precipitation behavior of MnS in the same process were also discussed.
Optical and structural characterization of oleic acid-stabilized CdTe nanocrystals for solution thin film processing

Directory of Open Access Journals (Sweden)

Claudio Davet Gutiérrez-Lazos

2014-06-01

Full Text Available This work presents results of the optical and structural characterization of oleic acid-stabilized cadmium telluride nanocrystals (CdTe-NC synthesized by an organometallic route. After being cleaned, the CdTe-NC were dispersed in toluene to obtain an ink-like dispersion, which was drop-cast on glass substrate to deposit a thin film. The CdTe-NC colloidal dispersion as well as the CdTe drop-cast thin films were characterized with regard to the optical and structural properties. TEM analysis indicates that the CdTe-NC have a nearly spherical shape (3.5 nm as mean size. Electron diffraction and XRD diffraction analyses indicated the bulk-CdTe face-centered cubic structure for CdTe-NC. An additional diffraction line corresponding to the octahedral Cd3P2 was also detected as a secondary phase, which probably originates by reacting free cadmium ions with trioctylphosphine (the tellurium reducing agent. The Raman spectrum exhibits two broad bands centered at 141.6 and 162.3 cm−1, which could be associated to the TO and LO modes of cubic CdTe nanocrystals, respectively. Additional peaks located in the 222 to 324 cm−1 range, agree fairly well with the wavenumbers reported for TO modes of octahedral Cd3P2.
The structure of high-quality aluminium cast iron

Directory of Open Access Journals (Sweden)

D. Kopyciński

2012-01-01

Full Text Available In this study presents the analyse of aluminium iron cast structure (as-cast condition which are used in high temperature. While producing the casts of aluminium iron major influence has been preserve the structure of technological process parameters. The addition to Fe-C-Al alloy V, Ti, Cr leads to the improvement of functional and mechanical cast qualities. In this study, a method was investigated to eliminate the presence of undesirable Al4C3 phases in a aluminium cast iron structure and thus improve the production process. V and Ti additions in aluminium cast iron allows to development of FeAl - VC or TiC alloys. In particular, V or Ti contents above 5 wt.% were found to totally eliminate the presence of Al4C3. In addition, preliminary work indicates that the alloy with the FeAl - VC or TiC structure reveals high oxidation resistance. The introduction of 5 wt.% chromium to aluminium cast iron strengthened Al4C3 precipitate. Thus, the resultant alloy can be considered an intermetallic FeAl matrix strengthened by VC and TiC or modified Al4C3 reinforcements.
Fluid flow and heat transfer modeling for castings

International Nuclear Information System (INIS)

Domanus, H.M.; Liu, Y.Y.; Sha, W.T.

1986-01-01

Casting is fundamental to manufacturing of many types of equipment and products. Although casting is a very old technology that has been in existence for hundreds of years, it remains a highly empirical technology, and production of new castings requires an expensive and time-consuming trial-and-error approach. In recent years, mathematical modeling of casting has received increasing attention; however, a majority of the modeling work has been in the area of heat transfer and solidification. Very little work has been done in modeling fluid flow of the liquid melt. This paper presents a model of fluid flow coupled with heat transfer of a liquid melt for casting processes. The model to be described in this paper is an extension of the COMMIX code and is capable of handling castings with any shape, size, and material. A feature of this model is the ability to track the liquid/gas interface and liquid/solid interface. The flow of liquid melt through the sprue and runners and into the mold cavity is calculated as well as three-dimensional temperature and velocity distributions of the liquid melt throughout the casting process. 14 refs., 13 figs
Clean Cast Steel Technology - Machinability and Technology Transfer

Energy Technology Data Exchange (ETDEWEB)

C. E. Bates; J. A. Griffin

2000-05-01

There were two main tasks in the Clean Cast Steel Technology - Machinability and Technology Transfer Project. These were (1) determine the processing facts that control the machinability of cast steel and (2) determine the ability of ladle stirring to homogenize ladle temperature, reduce the tap and pouring temperatures, and reduce casting scrap.
Influence of boron on ferrite formation in copper-added spheroidal graphite cast iron

Directory of Open Access Journals (Sweden)

Ying Zou

2014-07-01

Full Text Available This paper reviews the original work of the authors published recently, describing the influence of B on the matrix of the Cuadded spheroidal graphite cast iron. The effect of Cu has been corrected as a ferrite formation promoter in the matrix of the grey cast iron by the usage of high-purity material. Also, this paper focuses on the ferrite formation and the observation of the Cu distribution in the B-added and B-free Cu-containing spheroidal graphite cast iron. The Cu film on the spheroidal graphite can be successfully observed in the B-free sample using a special etching method. However, in the B-added sample, no Cu film could be found, while the secondary graphite was formed on the surface of the spheroidal graphite. The interaction between B and Cu is stressed as a peculiar phenomenon by the employment of a contrast experiment of B and Mn. The heat treatment could make Cu precipitate more significantly in the eutectic cells and in the matrix in the form of large Cu particles because of the limited solubility of Cu.
Preparation and Characteristics of Biodegradable Polyurethane/Clay Nanocomposite Films

Energy Technology Data Exchange (ETDEWEB)

Kim, Seong Woo [Kyonggi University, Suwon (Korea, Republic of)

2013-06-15

Biodegradable polyurethane (PU)/clay nanocomposite films were prepared via extrusion compounding process followed by casting film process. Organically modified montmorillonite (denoted as C30B) with a large amount of hydroxyl groups on its surface was used for the formation of strong bonding with PU resin. From both XRD analysis and TEM observations, the intercalated and exfoliated structure, and dispersion state of silicate platelets in the compounded nanocomposite films were confirmed. In addition, the rheological and tensile properties, optical transparency, oxygen permeability of the prepared nanocomposites were investigated as a function of added nanoclay content, and moreover based on these results, the correlation between the morphology and the resulting properties of the nanocomposites could be presented. The inclusion of nanoclays at appropriate content resulted in remarkable improvement in the nanocomposite performance including tensile modulus, elongation, transparency, and oxygen barrier property, however at excess amount of nanoclays, reduction or very slight increase was observed due to poor dispersion. The biodegradability of the prepared nanocomposite film was evaluated by examining the deterioration in the barrier and tensile properties during degradation period under compost.
The role of water in slip casting

Science.gov (United States)

Mccauley, R. A.; Phelps, G. W.

1984-01-01

Slips and casting are considered in terms of physical and colloidal chemistry. Casting slips are polydisperse suspensions of lyophobic particles in water, whose degree of coagulation is controlled by interaction of flocculating and deflocculating agents. Slip casting rate and viscosity are functions of temperature. Slip rheology and response to deflocculating agents varies significantly as the kinds and amounts of colloid modifiers change. Water is considered as a raw material. Various concepts of water/clay interactions and structures are discussed. Casting is a de-watering operation in which water moves from slip to cast to mold in response to a potential energy termed moisture stress. Drying is an evaporative process from a free water surface.
Qualitative Analysis of Films: Cultural Processes in the Mirror of Film

Directory of Open Access Journals (Sweden)

Gloria Dahl

2004-05-01

Full Text Available A special qualitative psychological analysis of movies developed by Wilhelm SALBER is practiced at the Psychological Institute of the University of Cologne for more than 40 years. This kind of film-analysis does not have an end in itself, but also aids as access to research cultural structures. In this respect movies are seismographs of cultural trends expressing general visions and images of future development. They indicate as well the status of society in its genesis and complexity as developmental perspectives, providing information about crisis, narrowing scope of action and its immanent self-healing power. Comparable to the process of dream-interpretation, the "manifest" film narration is expanded with the associations and in-depth descriptions of the audience in order to reconstruct the latent "Komplexentwicklung," the development of psychological lines. Suspense and spellbound is based on activating a meaningful transformational experience—only movies stimulate such a process which touch the heart of the viewers. The psychological analysis works out the morphological dramaturgy of the film-experience, which is shaped into a specific dynamic figure. Paradox insoluble problem-constellations are the driving forces in this moving process. The mere examination of the screenplay or the film-story does not take into consideration that the audience is always part of the scene. Viewers modify the story in a characteristic way while they are watching it—according to the dynamic of the psychological process they are going through. A combination of joining in and maintaining an observing distance—as in therapy, in advertising or in education—is an integral part of this interplay. Because the significant factors work unconsciously, it is necessary to apply a specific qualitative method in order to be able to grasp this. Short exemplary analyses of the movies The Piano, Fight Club, Dogville, Punch-Drunk Love, Catch Me If You Can, The Hours

Forward and Reverse Process Models for the Squeeze Casting Process Using Neural Network Based Approaches

Directory of Open Access Journals (Sweden)

Manjunath Patel Gowdru Chandrashekarappa

2014-01-01

Full Text Available The present research work is focussed to develop an intelligent system to establish the input-output relationship utilizing forward and reverse mappings of artificial neural networks. Forward mapping aims at predicting the density and secondary dendrite arm spacing (SDAS from the known set of squeeze cast process parameters such as time delay, pressure duration, squeezes pressure, pouring temperature, and die temperature. An attempt is also made to meet the industrial requirements of developing the reverse model to predict the recommended squeeze cast parameters for the desired density and SDAS. Two different neural network based approaches have been proposed to carry out the said task, namely, back propagation neural network (BPNN and genetic algorithm neural network (GA-NN. The batch mode of training is employed for both supervised learning networks and requires huge training data. The requirement of huge training data is generated artificially at random using regression equation derived through real experiments carried out earlier by the same authors. The performances of BPNN and GA-NN models are compared among themselves with those of regression for ten test cases. The results show that both models are capable of making better predictions and the models can be effectively used in shop floor in selection of most influential parameters for the desired outputs.
Intelligent Machine Vision Based Modeling and Positioning System in Sand Casting Process

Directory of Open Access Journals (Sweden)

Shahid Ikramullah Butt

2017-01-01

Full Text Available Advanced vision solutions enable manufacturers in the technology sector to reconcile both competitive and regulatory concerns and address the need for immaculate fault detection and quality assurance. The modern manufacturing has completely shifted from the manual inspections to the machine assisted vision inspection methodology. Furthermore, the research outcomes in industrial automation have revolutionized the whole product development strategy. The purpose of this research paper is to introduce a new scheme of automation in the sand casting process by means of machine vision based technology for mold positioning. Automation has been achieved by developing a novel system in which casting molds of different sizes, having different pouring cup location and radius, position themselves in front of the induction furnace such that the center of pouring cup comes directly beneath the pouring point of furnace. The coordinates of the center of pouring cup are found by using computer vision algorithms. The output is then transferred to a microcontroller which controls the alignment mechanism on which the mold is placed at the optimum location.
Microstructure control during twin roll casting of an AZ31 magnesium alloy

International Nuclear Information System (INIS)

Huang, Y; Bayandorian, I; Fan, Z

2012-01-01

The existing twin roll casting technique for magnesium alloys suffers heterogeneity in both microstructure and chemistry and downstream processing is required to improve the strip quality, resulting in cost rise. In the present work, twin roll casting was carried out using an AZ31 magnesium alloy, with the application of intensive shearing melt conditioning prior to casting. The effect of process parameters such as pouring temperature and casting speed on microstructure control during casting and subsequent downstream processing was studied. Experimental results showed that the melt conditioning treatment allowed the production of AZ31 strips with uniform and refined microstructure free of centreline segregations. It was also shown that an optimized combination of pouring temperature and casting speed, in conjunction with a strip thickness control operation, resulted in uniformly distributed stored energies due to enhanced plastic deformation, which promoted recrystallization during casting and subsequent heat treatment. Strips prepared by twin roll casting and homogenization developed similar microstructural features to those prepared by twin roll casting followed by lengthy downstream processing by homogenization, hot rolling and annealing and displayed a weaker basal texture, exhibiting a potentially better formability.
Numerical modelling of evaporation in a ceramic layer in the tape casting process

Energy Technology Data Exchange (ETDEWEB)

Jabbari, M.; Hattel, J. H. [Process Modelling Group, Department of Mechanical Engineering, Technical University of Denmark, Nils Koppels Allé, 2800 Kgs. Lyngby (Denmark); Jambhekar, V. A.; Helmig, R. [Department of Hydromechanics and Modelling of Hydrosystems, Institute for Modelling Hydraulic and Environmental Systems, Universität Stuttgart, Stuttgart (Germany)

2016-06-08

Evaporation of water from a ceramic layer is a key phenomenon in the drying process for the manufacturing of tape cast ceramics. This process contains mass, momentum and energy exchange between the porous medium and the free–flow region. In order to analyze such interaction processes, a Representative Elementary Volume (REV)–scale model concept is presented for coupling non–isothermal multi–phase compositional porous–media flow and single–phase compositional laminar free–flow. The preliminary results show the typical expected evaporation behaviour from a porous medium initially saturated with water, and its transport to the free–flow region according to the existent results from the literature.
Investigations on medical film processing in the city of Berlin

International Nuclear Information System (INIS)

Pape, U.

1986-01-01

An investigation on the methods of film processing in diagnostic radialogy departments can for instance be understood as a mere statistical representation of number and type of processing apparatus and film types, chemical methods and processing time, or it can be done as an attempt to objectively compare the film processing methods by means of a densitometric evaluation of equally exposed films of current usage within a given department. Such a comparative evaluation has been suggested by the diagnostics experts of the Berlin association of medical physicists, who presented their proposals within the course of project planning talks for a planned field test with a phantom for X-ray diagnostics, to be carried out in Berlin. (orig.) [de
Numerical Simulation of Cast Distortion in Gas Turbine Engine Components

International Nuclear Information System (INIS)

Inozemtsev, A A; Dubrovskaya, A S; Dongauser, K A; Trufanov, N A

2015-01-01

In this paper the process of multiple airfoilvanes manufacturing through investment casting is considered. The mathematical model of the full contact problem is built to determine stress strain state in a cast during the process of solidification. Studies are carried out in viscoelastoplastic statement. Numerical simulation of the explored process is implemented with ProCASTsoftware package. The results of simulation are compared with the real production process. By means of computer analysis the optimization of technical process parameters is done in order to eliminate the defect of cast walls thickness variation. (paper)
Study on Pot Forming of Induction Heater Type Rice Cookers by Forging Cast Process

Science.gov (United States)

Ohnishi, Masayuki; Yamaguchi, Mitsugi; Ohashi, Osamu

This paper describes a study result on pot fabrication by the forging cast process of stainless steel with aluminum. Rice cooked with the new bowl-shaped pot for the induction heater type rice cookers is better tasting than rice cooked with the conventional cylindrical one, due to the achievement of better heat conduction and convection. The conventional pot is made of the clad sheet, consisting of stainless steel and aluminum. However, it is rather difficult to form a bowl shape from the clad sheet, primarily due to the problem of a material spring back. The fabrication of a new type of a pot was made possible by means of the adoption of a forging cast process instead of the clad sheet. In this process, iron powder is inserted between stainless steel and aluminum in order to alleviate the large difference on the coefficient of expansion between each material. It was made clear that the application of two kinds of iron particle, namely 10 μm size powder on the stainless steel side and 44 μm on the aluminum side, enables the joints to become strong enough. The joint strength of the new pot by this fabrication process was confirmed by the tests of the shear strength and the fatigue tests together with the stress analysis.
Effect of oxide films, inclusions and Fe on reproducibility of tensile properties in cast Al–Si–Mg alloys: Statistical and image analysis

International Nuclear Information System (INIS)

Eisaabadi B, G.; Davami, P.; Kim, S.K.; Varahram, N.; Yoon, Y.O.; Yeom, G.Y.

2012-01-01

Double oxide films (hereafter: oxides), inclusions and Fe-rich phases are known to be the most detrimental defects in cast Al–Si–Mg alloys. The effects of these defects on reproducibility of tensile properties in Al–7Si–0.35Mg alloy have been investigated in this study. Four different casting conditions (low oxide—low Fe, high oxide—low Fe, low oxide—high Fe and high oxide—high Fe) were studied. In each case, 30 tensile test samples were prepared by casting in a metallic mold and machining (total of 120 tensile test samples). Results of tensile test were analyzed by Weibull three-parameter and mixture analyses. The microstructure and fracture surface of samples were studied by optical and scanning electron microscopes. Total of 800 metallography images (200 images for each experiment) were taken and analyzed by image analysis software. Finally, the relationship between tensile properties and defects characteristics was discussed. According to the results, Fe (Fe-related phases) had larger negative impact on tensile properties of the alloy compared to oxides. On the other hand, Weibull analysis revealed that the scattering of tensile properties was mainly due to the presence of oxides in microstructure. Results of image analysis showed that the shape factor and number of pores were mainly controlled by oxides and Fe, respectively. Also, there was a clear relationship between Weibull modules of UTS and El% and shape factor of pores. Furthermore, tensile properties of the examined alloy showed strong dependence to the number of pores.
Irradiation gamma on chitosan films

Energy Technology Data Exchange (ETDEWEB)

Mello, Luana Miranda Lopes de; Souza, Adriana Regia Marques de; Arthur, Valter, E-mail: lumilopes@hotmail.com, E-mail: drilavras@yahoo.com.br, E-mail: arthur@cena.usp.br [Universidade Federal do Tocantins (UFT), Palmas,TO (Brazil). Departmento de Ciencia e Tecnologia de Alimentos; Universidade Federal de Goias (UFGO), Goiania (Brazil). Departmento de Ciencia e Tecnologia de Alimentos; Centro de Energia Nuclear na Agricultura (CENA/USP), Piracicaba, SP (Brazil)

2017-11-01

Films are preformed structures, independent, that are used to wrap food after processing, increasing their shelf life and enhancing its bright and attractive appearance. They are prepared from biological materials as an alternative to the plastic synthetic containers to improve the quality of the environment. Chitosan is a biodegradable polymer composed of β-(1-4) linked D-glucosamine (deacetylated unit) and N-acetyl-D- glucosamine (acetylated unit). It is produced commercially by deacetylation of chitin, which is a structural component of the exoskeleton of crustaceans. She is able to form films and edible and/or biodegradable coatings. With the objective to evaluate the effect of different doses of gamma radiation (0, 5, 10 and 15 kGy) and chitosan concentrations (1 and 2%) in film properties, it was evaluated its optical, mechanical and morphological properties. The films were produced by casting. Irradiation did not affect the thickness of the films, but influenced its colors, increasing the tone of the film for a stronger yellowish color. This fact can be attributed to the increased concentration of C = O bonds of chitosan due to the breakdown of the chain reaction and the Maillard reaction. Irradiated films showed smoother surface and less rough, due to the degradation of the chitosan molecule and poor mechanical properties, not showing good flexibility and stretching. (author)
Irradiation gamma on chitosan films

International Nuclear Information System (INIS)

Mello, Luana Miranda Lopes de; Souza, Adriana Regia Marques de; Arthur, Valter

2017-01-01

Films are preformed structures, independent, that are used to wrap food after processing, increasing their shelf life and enhancing its bright and attractive appearance. They are prepared from biological materials as an alternative to the plastic synthetic containers to improve the quality of the environment. Chitosan is a biodegradable polymer composed of β-(1-4) linked D-glucosamine (deacetylated unit) and N-acetyl-D- glucosamine (acetylated unit). It is produced commercially by deacetylation of chitin, which is a structural component of the exoskeleton of crustaceans. She is able to form films and edible and/or biodegradable coatings. With the objective to evaluate the effect of different doses of gamma radiation (0, 5, 10 and 15 kGy) and chitosan concentrations (1 and 2%) in film properties, it was evaluated its optical, mechanical and morphological properties. The films were produced by casting. Irradiation did not affect the thickness of the films, but influenced its colors, increasing the tone of the film for a stronger yellowish color. This fact can be attributed to the increased concentration of C = O bonds of chitosan due to the breakdown of the chain reaction and the Maillard reaction. Irradiated films showed smoother surface and less rough, due to the degradation of the chitosan molecule and poor mechanical properties, not showing good flexibility and stretching. (author)
Review of the continuous casting of steel by strip casting technology. Twin roll method system

International Nuclear Information System (INIS)

Ibarrondo, I.

2008-01-01

In order to compete in the future steel market and to maintain market share, the steel makers will need to use new efficient technologies capable of supplying steel strip products of high quality at low cost. In this way, the strip casting technology by twin rol method is one of the most important research are in the iron and steel industry today. This review makes a general description of the strip casting technology as well as its different steps, such us; metal delivery and casting, solidification process, hot rolling reduction step, etc. Through mathematical and physical models, the influence on microstructure texture surface quality and mechanical properties of the materials obtained by this method are described as a function of processing parameters, specially the roughness of the rolls. the manufacturing of carbon, stainless and electrical steels involves smaller capital and operating cost, lower gas emissions, and an opportunity to create new grades due to a faster solidification rate that leads to a different solidification structures. In sight of all this it is likely that Strip Casting technology will make a profound impact on the manufacturing landscape of the 21 s t century. (Author) 177 refs
Sixty Years of Casting Research

Science.gov (United States)

Campbell, John

2015-11-01

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

Directory of Open Access Journals (Sweden)

D. Kakaš

2009-07-01

Full Text Available Porosity formation was detected in the casting thinnest section in the proximity of the as cast surface and near the wall centerline. In order to investigate the cause of the porosity formation light microscopy was used to define as cast structure. After initial findings SEM and EDS analyses were performed. Based on the results it is possible to define cause of the observed porosity. A number of pores originates from the mould filling stage and entrainment of the oxide films, while others appear due to insufficient feeding during solidification.
Economical surface treatment of die casting dies to prevent soldering in high pressure casting

International Nuclear Information System (INIS)

Fraser, D.T.; Jahedi, M.Z.

2001-01-01

This paper describes the use of a gas oxidation treatment of H13 tool steel to develop a compact iron oxide layer at the surface of core pins to prevent soldering in high pressure die casting. The performance of oxide layers in the protection of die steel against soldering during high pressure die casting was tested in a specially designed die using removable core pins and Al-11 Si-3 Cu casting alloy. The gas oxidation treatment can be applied at low temperatures and to large areas of the die surface. In addition this process is very cost effective compared to other coating processes such as physical vapour deposition (PVD), or thermo-reactive diffusion (TRD) coatings. This work demonstrated that surface treatment producing pure magnetite (Fe 3 O 4 ) layers are more protective than oxide layers containing a combination of Fe 3 O 4 (magnetite) and Fe 3 O 3 (haematite). The magnetite layer acts as a barrier between the die steel/casting alloy interface and prevents the formation of inter-metallic phases. Optical microscopy and scanning electron microscope were used to determine the thickness of the oxide layer, while X-ray diffraction was performed to determine the oxide phase structure
Development of vacuum continuous casting technology for uranium

International Nuclear Information System (INIS)

Lee, Y.S.; Kim, C. K.; Kim, K. H.; Lee, D. B.; Kim, J. D.; Jang, S. J.; Ahn, H. S.; Shin, Y. J.

2001-02-01

The spent fuel disposal process of new dry storage concept has been developed in KAERI, in which the uranium metal abstracted by Li-reduction of spent fuel will be formed to long rods and then the rods will be arranged uniformly in canister. The objective of this study is to review the feasibility of applying the continuous casting method to cast a long rod with modifying the vacuum high-frequency induction furnace to vacuum continuous casting system, which was normally used to cast the uranium. The results are as follows. With the nozzle size of 3mm and the withdrawal speed of 3.5 mm/sec, the length of 160mm, diameter of 30 mm continuous casting uranium bar was successfully cast. This result shows there might be a possibility of continuous casting of uranium and helps the design and fabrication of new continuous casting equipment
Comparing maximum intercuspal contacts of virtual dental patients and mounted dental casts.

Science.gov (United States)

Delong, Ralph; Ko, Ching-Chang; Anderson, Gary C; Hodges, James S; Douglas, W H

2002-12-01

Quantitative measures of occlusal contacts are of paramount importance in the study of chewing dysfunction. A tool is needed to identify and quantify occlusal parameters without occlusal interference caused by the technique of analysis. This laboratory simulation study compared occlusal contacts constructed from 3-dimensional images of dental casts and interocclusal records with contacts found by use of conventional methods. Dental casts of 10 completely dentate adults were mounted in a semi-adjustable Denar articulator. Maximum intercuspal contacts were marked on the casts using red film. Intercuspal records made with an experimental vinyl polysiloxane impression material recorded maximum intercuspation. Three-dimensional virtual models of the casts and interocclusal records were made using custom software and an optical scanner. Contacts were calculated between virtual casts aligned manually (CM), aligned with interocclusal records scanned seated on the mandibular casts (C1) or scanned independently (C2), and directly from virtual interocclusal records (IR). Sensitivity and specificity calculations used the marked contacts as the standard. Contact parameters were compared between method pairs. Statistical comparisons used analysis of variance and the Tukey-Kramer post hoc test (P= CM/C1 = CM/C2 > C2/IR > CM/IR > C1/IR, where ">" means "closer than." Within the limits of this study, occlusal contacts calculated from aligned virtual casts accurately reproduce articulator contacts.
A novel Graphene Oxide film: Synthesis and Dielectric properties

Science.gov (United States)

Canimkurbey, Betul; San, Sait Eren; Yasin, Muhammad; Köse, Muhammet Erkan

In this work, we used Hummers method to synthesize Graphene Oxide (GO) and its parallel plate impedance spectroscopic technique to investigate dielectric properties. Graphene Oxide films were coated using drop casting method on ITO substrate. To analyze film morphology, atomic force microscopy was used. Dielectrics measurements of the samples were performed using impedance analyzer (HP-4194) in frequency range (100 Hz to 10MHz) at different temperatures. It was observed that the films' AC conductivity σac varied with angular frequency, ω as ωS, with Sdirect current (DC) and Correlated Barrier Hopping (CBH) conductivity mechanisms at low and high frequency ranges, respectively. Using solution processed Graphene Oxide will provide potential for organic electronic applications through its photon absorption and transmittance capability in the visible range and excellent electrical parameters.
Colour Metallography of Cast Iron - Chapter 1: Introduction (Ⅰ

Directory of Open Access Journals (Sweden)

Zhou Jiyang

2009-02-01

Full Text Available Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application and combine cast iron technology with some hi-techs (for example, computer technology. Nevertheless, cast iron is a multi-element and multi-phase alloy and has complex and variety of structures and still has great development potential in structure and property. For further studying and developing cast iron, theoretical research work is important promise, and the study on solidification process and control mechanism of graphite morphology is fundamental for improving property of cast iron and developing new type of cast iron. Metallography of cast iron normally includes two sections: liquid phase transformation and solid phase transformation. The book, Colour Metallography of Cast Iron, uses colour metallography technique to study solidification structures of cast irons: graphite, carbides, austenite and eutectics; and focuses on solidification processes. With progress of modern solidification theory, the control of material solidification process becomes important measure for improving traditional materials and developing new materials. Solidification structure not only influences mechanical and physical properties of cast iron, but also affects its internal quality. The book uses a large amount of colour photos to describe the formation of solidification structures and their relations. Crystallization phenomena, which cannot be displayed with traditional metallography, are presented and more phase transformation information is obtained from these colour
Silk fibroin/pullulan blend films: Preparation and characterization

Energy Technology Data Exchange (ETDEWEB)

Shivananda, C. S.; Rao, B. Lakshmeesha; Madhukumar, R.; Asha, S. [Department of Studies in Physics, Mangalore University, Mangalagangotri – 574 199 (India); Sarojini, B. K. [Department of Industrial Chemistry, Mangalore University, Mangalagangotri, Mangalore –574 199 (India); Somashekhar, R. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore – 570 006 (India); Sangappa, Y., E-mail: syhalabhavi@yahoo.co.in [Department of Studies in Physics, Mangalore University, Mangalagangotri – 574 199 (India); School of Material Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States)

2016-05-23

In this work silk fibroin/pullulan blend films have been prepared by solution casting method. The blend films were examined for structural, and thermal properties using X-ray diffraction (XRD), thermogravimatric (TGA) and differential scanning calorimetry (DSC) analysis. The XRD results indicate that with the introduction of pullulan, the interaction between SF and pullulan in the blend films induced the conformation transition of SF films and amorphous phase increases with increasing pullulan ratio. The thermal properties of the blend films were improved significantly in the blend films.
Novel micro-patterning processes for thin film NiTi vascular devices

International Nuclear Information System (INIS)

Chun, Y J; Mohanchandra, K P; Carman, G P; Levi, D S; Fishbein, M C

2010-01-01

In order to create microscale features in thin film NiTi for use in vascular endografts, a novel 'lift-off process' was developed for use with deep reactive ion etching. A wet etching approach is compared to two variations of this new 'lift-off' process. The first lift-off process (lift-off I) used Si posts to define the features of NiTi film deposited on the Si substrate. This method produced fractures in the NiTi when the film was released. The lift-off II process used Si islands as substrate for the film while the Si wafer defined the specific geometric features. Lift-off II process allowed for the creation of various shape patterns (i.e., ellipse, diamond, circle, square, etc) in the range of 5–180 µm. The lift-off II process produced smooth and well aligned micro-patterns in thin film NiTi without the undercutting found in wet etching techniques. The micro-patterned thin film NiTi formed from the lift-off II process was used to cover a stent. In vivo tests were performed to evaluate the endothelialization though patterned thin films. Angiography, histopathology and SEM showed patency of the artery and uniformly promoted endothelial layer covering without thrombosis in both a medium and small artery

Excimer laser processing of ZnO thin films prepared by the sol-gel process

International Nuclear Information System (INIS)

Winfield, R.J.; Koh, L.H.K.; O'Brien, Shane; Crean, Gabriel M.

2007-01-01

ZnO thin films were prepared on soda-lime glass from a single spin-coating deposition of a sol-gel prepared with anhydrous zinc acetate [Zn(C 2 H 3 O 2 ) 2 ], monoethanolamine [H 2 NC 2 H 4 OH] and isopropanol. The deposited films were dried at 50 and 300 deg. C. X-ray analysis showed that the films were amorphous. Laser annealing was performed using an excimer laser. The laser pulse repetition rate was 25 Hz with a pulse energy of 5.9 mJ, giving a fluence of 225 mJ cm -2 on the ZnO film. Typically, five laser pulses per unit area of the film were used. After laser processing, the hexagonal wurtzite phase of zinc oxide was observed from X-ray diffraction pattern analysis. The thin films had a transparency of greater than 70% in the visible region. The optical band-gap energy was 3.454 eV. Scanning electron microscopy and profilometry analysis highlighted the change in morphology that occurred as a result of laser processing. This comparative study shows that our sol-gel processing route differs significantly from ZnO sol-gel films prepared by conventional furnace annealing which requires temperatures above 450 deg. C for the formation of crystalline ZnO
Quality Management and Control of Low Pressure Cast Aluminum Alloy

Science.gov (United States)

Zhang, Dianxi; Zhang, Yanbo; Yang, Xiufan; Chen, Zhaosong; Jiang, Zelan

2018-01-01

This paper briefly reviews the history of low pressure casting and summarizes the major production processes of low pressure casting. It briefly introduces the quality management and control of low pressure cast aluminum alloy. The main processes include are: preparation of raw materials, Melting, refining, physical and chemical analysis, K-mode inspection, sand core, mold, heat treatment and so on.
Effects of heat-treatment conditions on electrical properties of sol-gel-derived ferroelectric Pb(Zr,Ti)O3 thin films

International Nuclear Information System (INIS)

Shim, Donghyun; Pak, Jaemoon; Nam, Kuangwoo; Park, Gwangseo

2005-01-01

Pb(Zr,Ti)O 3 (PZT) films with Zr/Ti ratio of 50 : 50 were prepared by spin-casting at 3000 rpm for 30 sec on Pt/Ti/SiO 2 /Si substrates. After standard processing procedure, three different methods of annealing were conducted at 600 .deg. C : a single-step process carried out in (a) air, and (b) O 2 ambient, and (c) a 2-step process carried out in air, followed by an O 2 annealing process. These films were highly oriented along the (111) direction with large remnant polarization and low coercive voltage values. The films treated in O 2 had relatively larger polarization values, but the 2-step-annealed films possessed lower coercive voltage. Fatigue measurements were conducted until 1 X 10 10 switching cycles, resulting in abnormal switching characteristics for these films. A comparative study on the ferroelectric and fatigue properties will be emphasized.
Chemical Processing effects on the radiation doses measured by Film Dosimeter System

International Nuclear Information System (INIS)

Mihai, F.

2009-01-01

Halide film dosimetry is a quantitative method of measurement of the radiation doses. The fog density and chemical processing of the dosimeter film affect the radiation dose measurement accuracy. This work presents the effect of the developer solution concentration on the response of the dosimetric film which different fog densities. Thus, three batches of film, dosimeters with following fog density 0.312 ± 1.31 %, 0.71 ± 0.59% and 0.77 ± 0.81 %, were irradiated to 137 Cs standard source to dose value of 1mSv. The halide films have been chemical processed at different concentrations of the developer solution: 20 %; 14.29 %; 11.11%; all other physics-chemical conditions in baths of development have been kept constants. Concentration of 20% is considered to be chemical processed standard conditions of the films. In case of the films exposed to 1 mSv dose, optical density recorded on the low fog films processed at 20% developer solution is rather closed of high fog film optical densities processed at 11.11% developer solution concentration. Also, the chemical processing effect on the image contrast was taken into consideration
Active packaging from chitosan-titanium dioxide nanocomposite film for prolonging storage life of tomato fruit.

Science.gov (United States)

Kaewklin, Patinya; Siripatrawan, Ubonrat; Suwanagul, Anawat; Lee, Youn Suk

2018-06-01

The feasibility of active packaging from chitosan (CS) and chitosan containing nanosized titanium dioxide (CT) to maintain quality and extend storage life of climacteric fruit was investigated. The CT nanocomposite film and CS film were fabricated using a solution casting method and used as active packaging to delay ripening process of cherry tomatoes. Changes in firmness, weight loss, a*/b* color, lycopene content, total soluble solid, ascorbic acid, and concentration of ethylene and carbon dioxide of the tomatoes packaged in CT film, CS film, and control (without CT or CS films) were monitored during storage at 20°C. Classification of fruit quality as a function of different packaging treatments was visualized using linear discriminant analysis. Tomatoes packaged in the CT film evolved lower quality changes than those in the CS film and control. The results suggested that the CT film exhibited ethylene photodegradation activity when exposed to UV light and consequently delayed the ripening process and changes in the quality of the tomatoes. Copyright © 2018 Elsevier B.V. All rights reserved.
Characterization of Aldehyde Crosslinked Kenaf Regenerated Cellulose Film

Directory of Open Access Journals (Sweden)

Hatika Kaco

2015-08-01

Full Text Available Regenerated cellulose film with better mechanical properties was successfully produced by introducing aldehyde crosslinker during the regeneration process. The cellulose source material was derived from kenaf core powder and dissolved in LiOH/urea solvent at −13 °C to form a cellulose solution. The cellulose solution was cast and coagulated in a crosslinker bath at different percentages of glutaraldehyde (GA and glyoxal (GX to form a regenerated cellulose film. According to Fourier transform infrared spectroscopy (FTIR spectra, the hydroxyl group of the cellulose was reduced, reducing the percentage of swelling as the percentage of crosslinker was increased. X-ray diffraction (XRD patterns showed that the crystallinity index of the crosslinked film was decreased. The pore size of the films decreased as the percentage of crosslinker was increased, resulting in decreased film transparency. The pore volume and percentage of swelling in water of the films also increased with decreases in the pore size as the percentage of crosslinker was increased. The tensile strengths of the GA- and GX-crosslinked films increased by 20 and 15% with the addition of 20% of each crosslinker, respectively.
The Design and Construction Process of a Test Stand for Casting the Power Steering’S Housing with the Use of the Pdcpd Material

Science.gov (United States)

Sobek, M.; Baier, A.; Grabowski, Ł.

2018-01-01

The use of new technologies and materials in various industries is a natural process that is directly related to the very high rate of development of these technologies. Certain industries decide to much faster introduce new technologies and materials. One of such branches is the automotive industry, whose representatives are very energetically looking for both financial savings and savings resulting from the vehicles mass reduction. An economically justified approach to construction materials is leading the search for new solutions and materials. The use of a modern material such as the two-component PDCPD composite shows hitherto unknown possibilities of producing subassemblies of many different constructions. The possibility of using a modern composite material with parameters comparable to that of metals and significantly lighter, can be an excellent alternative in the selection of materials for many parts of motor vehicles. The potentiality of precise casting of tolerated surfaces will allow to reduce the operations related to machining process, which is an indispensable part of the production process of elements that are cast of metal. This article describes the process of designing and building a test stand for precise positioning of power steering gear components at the stage of casting their housing. The article presents the principle of operation of the test stand and the process of preparation for the casting and the cast itself will be rudely described. Due to the implementation of research as part of a research project with an industrial partner, the article will only describe some operations. This is related to the confidentiality of the project.
Investigation of Shrinkage Defect in Castings by Quantitative Ishikawa Diagram

Directory of Open Access Journals (Sweden)

Chokkalingam B.

2017-03-01

Full Text Available Metal casting process involves processes such as pattern making, moulding and melting etc. Casting defects occur due to combination of various processes even though efforts are taken to control them. The first step in the defect analysis is to identify the major casting defect among the many casting defects. Then the analysis is to be made to find the root cause of the particular defect. Moreover, it is especially difficult to identify the root causes of the defect. Therefore, a systematic method is required to identify the root cause of the defect among possible causes, consequently specific remedial measures have to be implemented to control them. This paper presents a systematic procedure to identify the root cause of shrinkage defect in an automobile body casting (SG 500/7 and control it by the application of Pareto chart and Ishikawa diagram. with quantitative Weightage. It was found that the root causes were larger volume section in the cope, insufficient feeding of riser and insufficient poured metal in the riser. The necessary remedial measures were taken and castings were reproduced. The shrinkage defect in the castings was completely eliminated.
A plasmaless, photochemical etch process for porous organosilicate glass films

Science.gov (United States)

Ryan, E. Todd; Molis, Steven E.

2017-12-01

A plasmaless, photochemical etch process using ultraviolet (UV) light in the presence of NH3 or O2 etched porous organosilicate glass films, also called pSiCOH films, in a two-step process. First, a UV/NH3 or UV/O2 treatment removed carbon (mostly methyl groups bonded to silicon) from a pSiCOH film by demethylation to a depth determined by the treatment exposure time. Second, aqueous HF was used to selectively remove the demethylated layer of the pSiCOH film leaving the methylated layer below. UV in the presence of inert gas or H2 did not demethylate the pSiCOH film. The depth of UV/NH3 demethylation followed diffusion limited kinetics and possible mechanisms of demethylation are presented. Unlike reactive plasma processes, which contain ions that can damage surrounding structures during nanofabrication, the photochemical etch contains no damaging ions. Feasibility of the photochemical etching was shown by comparing it to a plasma-based process to remove the pSiCOH dielectric from between Cu interconnect lines, which is a critical step during air gap fabrication. The findings also expand our understanding of UV photon interactions in pSiCOH films that may contribute to plasma-induced damage to pSiCOH films.
In situ polymerization process of polypyrrole ultrathin films

International Nuclear Information System (INIS)

Onoda, Mitsuyoshi; Tada, Kazuya; Shinkuma, Akira

2006-01-01

A novel thin film processing technique has been developed for the fabrication of ultrathin films of conducting polymers with molecular-level control over thickness and multilayer architecture. This new self-assembly process opens up vast possibilities in applications which require large area, ultrathin films of conducting polymers and more importantly in applications that can take advantage of the unique interactions achievable in the complex, supermolecular architectures of multilayer films. In in situ polymerized polypyrrole (PPy), the deposition process strongly depends on the nature of the substrate surface. That is, for a surface that is negatively charged, there is a linear correspondence between dipping time and the amount of PPy deposited on the substrate. However, in the case of a positively charged surface, there is an apparent rest period of approximately 10-20 min, during which no PPy is deposited. From optical absorption spectroscopy and photoelectron emission studies etc., it became clear that oligomers of pyrrole were adsorbed on the positively charged surface during the rest period, as a result the polymerization reaction of PPy could proceed
PVA/Polysaccharides Blended Films: Mechanical Properties

OpenAIRE

Silva, Fábio E. F.; Di-Medeiros, Maria Carolina B.; Batista, Karla A.; Fernandes, Kátia F.

2013-01-01

Blends of polyvinyl alcohol (PVA) and angico gum (AG) and/or cashew gum (CG) were used to produce films by casting method. Morphological and mechanical properties of these films were studied and compared to the properties of a commercial collagen membrane of bovine origin (MBO). The films presented thickness varying from 70 to 140 μm (PVA/AG) and 140 to 200 μm (PVA/CG). Macroscopic analysis showed that a PVA/CG film was very similar to MBO regarding the color and transparency. The higher valu...
Repair welding of cast iron coated electrodes

Science.gov (United States)

Żuk, M.; Górka, J.; Dojka, R.; Czupryński, A.

2017-08-01

Welding cast iron is a complex production procedure. Repair welding was used to repair damaged or poorly made castings. This is due to a tendency to cracking of the material during welding as well as after it. Welding cast iron can be carried out on hot or on cold. Hot welding requires high heat material and the use of welding material in the form of cast iron. In the case of cold welding, it is possible to use different materials. Mostly used filler metals are nickel and copper based. The work shows the course of research concerning repairmen of ductile iron with arc welding method. For the reparation process four types of ESAB company coated electrodes dedicated for cast iron were used with diameter 3.2 and 4 mm: ES 18-8-6B (4mm), EB 150 (4mm), OK NiCl, EŻM. In the cast iron examined during the testing grooves were made using plasma methods, in order to simulate the removed casting flaws. Then the welding process with coated electrodes was executed. The process utilized low welding current row of 100A, so there would only be a small amount of heat delivered to the heat affected zone (HAZ). Short stitches were made, after welding it was hammered, in order to remove stresses. After the repair welding the part of studies commenced which purpose was finding surface defects using visual testing (VT) and penetration testing (PT). In the second part, a series of macro and microscopic studies were executed witch the purpose of disclosuring the structure. Then the hardness tests for welds cross sections were performed. An important aspect of welding cast iron is the colour of the padding weld after welding, more precisely the difference between the base material and padding weld, the use of different materials extra gives the extra ability to select the best variant. The research of four types of coated electrode was executed, based on the demands the best option in terms of aesthetic, strength and hardness.
Triple Plate Mold Final Report: Optimization of the Mold Design and Casting Parameters for a Thin U-10mo Fuel Casting

Energy Technology Data Exchange (ETDEWEB)

Aikin, Jr., Robert M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-01-04

This work describes the experiments and modeling that have been performed to improve and try to optimize the simultaneous casting of three plates of U-10wt%Mo in a single coil vacuum induction melting (VIM) furnace. The plates of interest are 280 mm wide by 203 mm tall by 5 mm thick (11" x 8" x 0.2"). The initial mold design and processing parameters were supplied by Y-12. The mold and casting cavity were instrumented with a number of thermocouples, and the casting performed to determine the thermal history of the mold and casting. The resulting cast plates were radiographed and numerous defects identified. Metallography was performed to help identify the nature of the radiographically observed defects. This information was then used to validate a mold filling and solidification model of that casting. Based on the initial casting, good casting design practice, and process simulation of several design alternatives, a revised design was developed with the goal of minimizing casting defects such as porosity. The redesigned mold had a larger hot-top and had its long axis along the horizontal direction. These changes were to try to develop a strong thermal gradient conducive to good feeding and minimization of micro- and macroporosity in the cast plates. An instrumented casting was then performed with the revised mold design and a linear distributor. This design yielded cast plates with significantly less radiographically identified defects. Unfortunately, there was significant variation in plate weight and metal content in their hot-tops. Fluid flow simulations were then performed on this mold/distributor design. This helped identify the issue with this linear distributor design. Additional simulations were then performed on candidate distributor redesigns and a preferred distributor annular design was identified. This improved annular design was used to produce a third instrumented casting with favorable results. These refined designs and their radiographic
Quality problems root cause identification and variability reduction in casting processes

Directory of Open Access Journals (Sweden)

G. Furgał

2009-01-01

Full Text Available Increasing customer requirements and production costs force casting manufacturers to adopt a methodological approach to manufacturingprocesses, in order to deliver increasingly more repeatable, predictable and competitive products. One of the methods of achieving such results is the reduction of variability of manufacturing processes and the optimization of their control. This paper presents the possibilities granted by the Six Sigma methodology in efficient identification of special factors influencing pre-heat of ceramic moulds and castingparameters, in the minimization of the frequency at which they occur, and in the reduction of key process parameters variability. This paper also shows the usability of the method in achieving measurable business advantages for the company using the example of one DMAIC methodology based project realized in the Investment Foundry Department of WSK “PZL-Rzeszow” S.A.
PROCESSING OF CONCENTRATED AQUEOUS ZIRCONIA-BIOGLASS SLIPS BY SLIP CASTING

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Beltina Leon

2017-03-01

Full Text Available 3 mol% yttria-partially stabilized zirconia (Y-TZP powder and a sol-gel derived CaO- P₂O₅- SiO₂ (64S bioglass, were used to produce Y-TZP- bioglass slip cast compacts. The rheological properties of concentrated aqueous Y-TZP- 64S suspensions prepared with two different glass contents: 10.5 vol% and 19.9 vol%, and ammonium polyacrylate (NH₄PA as dispersant, were investigated and compared with those of Y-TZP. The density of green cast samples was related to the degree of slip dispersion. The substitution of Y-TZP by 64S glass in the mixtures resulted in greater adsorption of NH₄PA; however, the viscosity and yield stress values of Y-TZP-64S slips were higher than those of Y-TZP ones for the solid loadings studied. The increase in the glass content from 10.5 to 19.9 vol% increased the viscosity and yield stress values. The presence of 64S glass in the mixtures resulted in a less dense packing of cast samples.
Fibreglass Total Contact Casting, Removable Cast Walkers, and Irremovable Cast Walkers to Treat Diabetic Neuropathic Foot Ulcers: A Health Technology Assessment

Science.gov (United States)

Costa, Vania; Tu, Hong Anh; Wells, David; Weir, Mark; Holubowich, Corinne; Walter, Melissa

2017-01-01

Background Diabetic neuropathic foot ulcers are a risk factor for lower leg amputation. Many experts recommend offloading with fibreglass total contact casting, removable cast walkers, and irremovable cast walkers as a way to treat these ulcers. Methods We completed a health technology assessment, which included an evaluation of clinical benefits and harms, value for money, and patient preferences for offloading devices. We performed a systematic literature search on August 17, 2016, to identify randomized controlled trials that compared fibreglass total contact casting, removable cast walkers, and irremovable cast walkers with other treatments (offloading or non-offloading) in patients with diabetic neuropathic foot ulcers. We developed a decision-analytic model to assess the cost-effectiveness of fibreglass total contact casting, removable cast walkers, and irremovable cast walkers, and we conducted a 5-year budget impact analysis. Finally, we interviewed people with diabetes who had lived experience with foot ulcers, asking them about the different offloading devices and the factors that influenced their treatment choices. Results We identified 13 randomized controlled trials. The evidence suggests that total contact casting, removable cast walkers, and irremovable cast walkers are beneficial in the treatment of neuropathic, noninfected foot ulcers in patients with diabetes but without severe peripheral arterial disease. Compared to removable cast walkers, ulcer healing was improved with total contact casting (moderate quality evidence; risk difference 0.17 [95% confidence interval 0.00–0.33]) and irremovable cast walkers (low quality evidence; risk difference 0.21 [95% confidence interval 0.01–0.40]). We found no difference in ulcer healing between total contact casting and irremovable cast walkers (low quality evidence; risk difference 0.02 [95% confidence interval −0.11–0.14]). The economic analysis showed that total contact casting and irremovable
Morphological Influence of Solution-Processed Zinc Oxide Films on Electrical Characteristics of Thin-Film Transistors

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Hyeonju Lee

2016-10-01

Full Text Available We report on the morphological influence of solution-processed zinc oxide (ZnO semiconductor films on the electrical characteristics of ZnO thin-film transistors (TFTs. Different film morphologies were produced by controlling the spin-coating condition of a precursor solution, and the ZnO films were analyzed using atomic force microscopy, X-ray diffraction, X-ray photoemission spectroscopy, and Hall measurement. It is shown that ZnO TFTs have a superior performance in terms of the threshold voltage and field-effect mobility, when ZnO crystallites are more densely packed in the film. This is attributed to lower electrical resistivity and higher Hall mobility in a densely packed ZnO film. In the results of consecutive TFT operations, a positive shift in the threshold voltage occurred irrespective of the film morphology, but the morphological influence on the variation in the field-effect mobility was evident. The field-effect mobility in TFTs having a densely packed ZnO film increased continuously during consecutive TFT operations, which is in contrast to the mobility decrease observed in the less packed case. An analysis of the field-effect conductivities ascribes these results to the difference in energetic traps, which originate from structural defects in the ZnO films. Consequently, the morphological influence of solution-processed ZnO films on the TFT performance can be understood through the packing property of ZnO crystallites.
Combined testing of castings having rough surface

International Nuclear Information System (INIS)

Polyakov, Yu.O.; Zav'yalkin, F.M.; Moskvin, V.N.

1988-01-01

Mathematical models of a flaw detector for complex testing of castings, containing radiometric and pneumatic converters, are developed and investigated. The efficiency of compensation of casting thickness fluctuation effect on the results of testing in combined information processing obtained by various methods is estimated
Effect of flask vibration time on casting integrity, Surface Penetration and Coating Inclusion in lost foam casting of Al-Si Alloy

International Nuclear Information System (INIS)

Karimian, Majid; Idris, M. H.; Ourdjini, A.; Muthu, Kali

2011-01-01

The paper presents the result of an experimental investigation conducted on medium aluminum silicon alloy casting- LM6, using no-vacuum assisted lost foam casting process. The study is directed for establishing the relationship between the flask vibrations times developed for molded sample on the casting integrity, surface penetration and coating inclusion defects of the casting. Four different flask vibration times namely 180, 120, 90 and 60 sec. were investigated. The casting integrity was investigated in terms of fulfilling in all portions and edges. The surface penetration was measured using optical microscope whilst image analyzer was used to quantify the percentage of coating inclusion in the casting. The results show that vibration time has significant influence on the fulfilling as well as the internal integrity of the lost foam casting. It was found that the lower vibration time produced comparatively sound casing.
Biopolymer nanocomposite films reinforced with nanocellulose whiskers

Science.gov (United States)

Amit Saxena; Marcus Foston; Mohamad Kassaee; Thomas J. Elder; Arthur J. Ragauskas

2011-01-01

A xylan nanocomposite film with improved strength and barrier properties was prepared by a solution casting using nanocellulose whiskers as a reinforcing agent. The 13C cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance (NMR) analysis of the spectral data obtained for the NCW/xylan nanocomposite films indicated the signal intensity originating...

The X-ray Telescope of CAST

CERN Document Server

Kuster, M.; Cebrian, S.; Davenport, M.; Elefteriadis, C.; Englhauser, J.; Fischer, H.; Franz, J.; Friedrich, P.; Hartmann, R.; Heinsius, F.H.; Hoffmann, D.H.H.; Hoffmeister, G.; Joux, J.N.; Kang, D.; Konigsmann, Kay; Kotthaus, R.; Papaevangelou, T.; Lasseur, C.; Lippitsch, A.; Lutz, G.; Morales, J.; Rodriguez, A.; Struder, L.; Vogel, J.; Zioutas, K.

2007-01-01

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.
Schwann cell interactions with polymer films are affected by groove geometry and film hydrophilicity

International Nuclear Information System (INIS)

Mobasseri, S A; Downes, S; Terenghi, G

2014-01-01

We have developed a biodegradable polymer scaffold made of a polycaprolactone/polylactic acid (PCL/PLA) film. Surface properties such as topography and chemistry have a vital influence on cell–material interactions. Surface modifications of PCL/PLA films were performed using topographical cues and UV–ozone treatment to improve Schwann cell organisation and behaviour. Schwann cell attachment, alignment and proliferation were evaluated on the grooved UV–ozone treated and non-treated films. Solvent casting of the polymer solution on patterned silicon substrates resulted in films with different groove shapes: V (V), sloped (SL) and square (SQ) shapes. Pitted films, with no grooves, were prepared as a negative control. The UV–ozone treatment was performed to increase hydrophilicity. The process specifications for UV–ozone treatment were evaluated and 5 min radiation time and 6 cm distance to the UV source were suggested as the optimal practise. When cultured on grooved films, Schwann cells elongated on the V and SL shape grooves without crossing over, and grew in the direction of the grooves. However, there was less elongation with more crossing over on the SQ shape grooves. The maximum cell length (511 μm) was observed on the treated V-grooved films. The cells cultured on pitted UV–ozone treated surfaces showed random arrangements with no increase in length. We have demonstrated that the synergic effects of physical cues combined with UV–ozone treatment have the potential to enhance Schwann cell morphology and alignment. (paper)
Development of High-Performance Cast Crankshafts. Final Technical Report

Energy Technology Data Exchange (ETDEWEB)

Bauer, Mark E [General Motors, Detroit, MI (United States)

2017-03-31

The objective of this project was to develop technologies that would enable the production of cast crankshafts that can replace high performance forged steel crankshafts. To achieve this, the Ultimate Tensile Strength (UTS) of the new material needs to be 850 MPa with a desired minimum Yield Strength (YS; 0.2% offset) of 615 MPa and at least 10% elongation. Perhaps more challenging, the cast material needs to be able to achieve sufficient local fatigue properties to satisfy the durability requirements in today’s high performance gasoline and diesel engine applications. The project team focused on the development of cast steel alloys for application in crankshafts to take advantage of the higher stiffness over other potential material choices. The material and process developed should be able to produce high-performance crankshafts at no more than 110% of the cost of current production cast units, perhaps the most difficult objective to achieve. To minimize costs, the primary alloy design strategy was to design compositions that can achieve the required properties with minimal alloying and post-casting heat treatments. An Integrated Computational Materials Engineering (ICME) based approach was utilized, rather than relying only on traditional trial-and-error methods, which has been proven to accelerate alloy development time. Prototype melt chemistries designed using ICME were cast as test specimens and characterized iteratively to develop an alloy design within a stage-gate process. Standard characterization and material testing was done to validate the alloy performance against design targets and provide feedback to material design and manufacturing process models. Finally, the project called for Caterpillar and General Motors (GM) to develop optimized crankshaft designs using the final material and manufacturing processing path developed. A multi-disciplinary effort was to integrate finite element analyses by engine designers and geometry-specific casting
CASTING IMPROVEMENT BASED ON METAHEURISTIC OPTIMIZATION AND NUMERICAL SIMULATION

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Radomir Radiša

2017-12-01

Full Text Available This paper presents the use of metaheuristic optimization techniques to support the improvement of casting process. Genetic algorithm (GA, Ant Colony Optimization (ACO, Simulated annealing (SA and Particle Swarm Optimization (PSO have been considered as optimization tools to define the geometry of the casting part’s feeder. The proposed methodology has been demonstrated in the design of the feeder for casting Pelton turbine bucket. The results of the optimization are dimensional characteristics of the feeder, and the best result from all the implemented optimization processes has been adopted. Numerical simulation has been used to verify the validity of the presented design methodology and the feeding system optimization in the casting system of the Pelton turbine bucket.
Effect of parameters of high-pressure die casting on occurrence of casting nonconformities in sleeves of silumin alloy EN AB 47100

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Pałyga Ł.

2017-03-01

Full Text Available The paper presents a research on the effect of extreme - for the technology of the considered silumin EN AB 47100 - parameters of high-pressure die casting on occurrence of casting nonconformities. Considered was influence of the way of assembling the mould cooled-down to 140-160°C, non-standard for the selected casting, and pouring temperature in the range of 705 to 720°C (higher than the recommended of non-refined alloy. The castings were prepared with use of a high-pressure casting machine made by Kirov with mould closing force of 2500 kN. Occurrence of nonconformities was evaluated on properly prepared specimens taken from the castings manufactured with various parameters of the injection piston and various multiplication pressures. The results were subjected to quantitative and qualitative analyses of casting nonconformities and distribution of major alloying elements. It was found that proper selection of working parameters of the casting machine, in spite of disadvantageous pouring conditions, makes it possible to reduce occurrence of some casting defects, like shrinkage cavities and porosity, to improve tightness of castings even when the alloy refining process is omitted.
Delamination wear mechanism in gray cast irons

International Nuclear Information System (INIS)

Salehi, M.

2000-01-01

An investigation of the friction and sliding wear of gray cast iron against chromium plated cast irons was carried out on a newly constructed reciprocating friction and wear tester. The tests were the first to be done on the test rig under dry conditions and at the speed of 170 cm/min, and variable loads of 20-260 N for a duration of 15 min. to 3 hours. The gray cast iron surfaces worn by a process of plastic deformation at the subsurface, crack nucleation, and crack growth leading to formation of plate like debris and therefore the delamination theory applies. No evidence of adhesion was observed. This could be due to formation of oxides on the wear surface which prevent adhesion. channel type chromium plating ''picked'' up cast iron from the counter-body surfaces by mechanically trapping cast iron debris on and within the cracks. The removal of the plated chromium left a pitted surface on the cast iron
Dye film dosimetry for radiation processing

International Nuclear Information System (INIS)

Humphreys, J.C.; McLaughlin, W.L.

1981-01-01

Commercially available plastic films containing dyes or dye precursors are convenient dosimeters and imaging media for electron beams or photons used for industrial radiation processing. As ''grainless'' imaging systems having thicknesses down to a few micrometers, they provide high spatial resolution for determining detailed absorbed dose distributions through microdensitometric analysis. The radiation absorption properties of these systems are adjusted by changing film composition so that the dosimeter materials can be made to simulate the material of interest undergoing irradiation. Other advantages include long-term stability, dose-rate independence, and ease of use and calibration. Radiochromic dye films with thicknesses varying from 0.005 to 1 mm are presently used to monitor electron-beam or gamma-ray doses from 10 to 10 5 Gy (10 3 to 10 7 rad), typical of those encountered in medical applications, radiation curing of polymeric composites, wire and cable insulation, shrinkable plastic tubing and film, as well as sterilization of medical supplies and treatment of municipal and industrial wastes. An NBS calibration service to industry involves the traceability of standard 60 Co gamma ray absorbed dose measurements by means of these films employed as transfer standards
Formulation of chitosan-based ciprofloxacin and diclofenac film for ...

African Journals Online (AJOL)

Purpose: This study was designed to develop and evaluate chitosan films containing ciprofloxacin and diclofenac sodium for the topical treatment of periodontitis. Methods: Chitosan films containing ciprofloxacin alone and in combination with diclofenac sodium were prepared by solvent casting method. Some of the ...
Rapid deposition process for zinc oxide film applications in pyroelectric devices

International Nuclear Information System (INIS)

Hsiao, Chun-Ching; Yu, Shih-Yuan

2012-01-01

Aerosol deposition (AD) is a rapid process for the deposition of films. Zinc oxide is a low toxicity and environmentally friendly material, and it possesses properties such as semiconductivity, pyroelectricity and piezoelectricity without the poling process. Therefore, AD is used to accelerate the manufacturing process for applications of ZnO films in pyroelectric devices. Increasing the temperature variation rate in pyroelectric films is a useful method for enhancing the responsivity of pyroelectric devices. In the present study, a porous ZnO film possessing the properties of large heat absorption and high temperature variation rate is successfully produced by the AD rapid process and laser annealing for application in pyroelectric devices. (paper)
Investment Casting vs Replicast CS Considered in Terms of the Ceramic Mould Making and Dimensional Accuracy of Castings

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Karwiński A.

2014-03-01

Full Text Available The article presents an analysis of the applicability of the Replicast CS process as an alternative to the investment casting process, considered in terms of the dimensional accuracy of castings. Ceramic shell moulds were based on the Ekosil binder and a wide range of ceramic materials, such as crystalline quartz, fused silica, aluminosilicates and zirconium silicate. The linear dimensions were measured with a Zeiss UMC 550 machine that allowed reducing to minimum the measurement uncertainty
Fabrication and mechanical characterization of biodegradable and synthetic polymeric films: Effect of gamma radiation

Science.gov (United States)

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

2012-08-01

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

International Nuclear Information System (INIS)

Fielding, Randall S.; Kennedy, J.R.; Crapps, J.; Unal, C.

2013-01-01

Conclusions: • Gravity casting is a feasible process for casting of metallic fuels: – May not be as robust as CGIC, more parameter dependent to find right “sweet spot” for high quality castings; – Fluid flow is very important and is affected by mold design, vent size, super heat, etc.; – Pressure differential assist was found to be detrimental. • Simulation found that vent location was important to allow adequate filling of mold; • Surface tension plays an important role in determining casting quality; • Casting and simulations high light the need for better characterized fluid physical and thermal properties; • Results from simulations will be incorporated in GACS design such as vent location and physical property characterization
Physical Evaluation of PVA/Chitosan Film Blends with Glycerine and Calcium Chloride

Science.gov (United States)

Nugraheni, A. D.; Purnawati, D.; Kusumaatmaja, A.

2018-04-01

PVA/chitosan film has been fabricated by using drop casting method. PVA/chitosan film is produced by dissolving 2% (w/v) PVA solution and 2% (w/v) chitosan solution. PVA/chitosan film is produced with weight ratio variation (w/w) 100/0, 75/25, 50/50 and 0/100. The film is fabricated using drop casting method in Petry dish with diameter 11 cm at room temperature and RH 50%–60% during seven days. The mechanical properties were characterized by using Universal Technical Machine (UTM) and UV-Vis to understand the physical properties of weight ratio (w/w) of PVA/Chitosan film by addition of plasticizer and calcium chloride. The film thickness tends to decrease with PVA content. The addition of chitosan will increase film thickness, and it will decrease swelling index, elongation (%), and transmittance of UV rays. The additions of plasticizer to PVA/Chitosan film will increase film thickness and elongation (%), and it will decrease swelling index, tensile strength and transmittance of UV rays. The crosslink of PVA/Chitosan film with calcium chloride will decrease film thickness, swelling index, elongation (%) and transmittance of UV rays, and increase tensile strength.
Ejection Performance of Coated Core Pins Intended for Application on High Pressure Die Casting Tools for Aluminium Alloys Processing

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P. Terek

2017-09-01

Full Text Available In high pressure die casting (HPDC process of aluminium alloys cast alloy soldering severely damages tool surfaces. It hampers casting ejection, reduces the casting quality and decreases the overall production efficiency. Thin ceramic PVD (physical vapor deposition coatings applied on tool surfaces successfully reduce these effects. However, their performance is still not recognised for surfaces with various topographies. In this investigation, soldering tendency of Al-Si-Cu alloy toward EN X27CrMoV51 steel, plasma nitrided steel, CrN and TiAlN duplex PVD coatings is evaluated using ejection test. The coatings were prepared to a range of surface roughness and topographies. After the tests sample surfaces were analysed by different microscopy techniques and profilometry. It was found that the ejection performance is independent of the chemical composition of investigated materials. After the ejection, the cast alloy soldering layer was found on surfaces of all tested materials. This built-up layer formed by effects of mechanical soldering, without corrosion reactions. Coated samples displayed a pronounced dependence of ejection force on surface roughness and topography. By decreasing roughness, ejection force increased, which is a consequence of intensified adhesion effects. Presented findings are a novel information important for efficient application of PVD coatings intendent for protection of HPDC tools.
The casting of western sculpture during the XIXth century: sand casting versus lost wax casting

NARCIS (Netherlands)

Beentjes, T.P.C.

2014-01-01

This paper will discuss research into bronze casting techniques as practiced during the XIXth and early XXth century. Both natural sand casting (fonte au sable naturel) and lost wax casting (fonte à la cire perdue) were employed during this period and sometimes rivalled for commissions. Before the
Strategy of Cooling Parameters Selection in the Continuous Casting of Steel

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Falkus J.

2016-03-01

Full Text Available This paper presents a strategy of the cooling parameters selection in the process of continuous steel casting. Industrial tests were performed at a slab casting machine at the Arcelor Mittal Poland Unit in Krakow. The tests covered 55 heats for 7 various steel grades. Based on the existing casting technology a numerical model of the continuous steel casting process was formulated. The numerical calculations were performed for three casting speeds - 0.6, 0.8 and 1 m min-1. An algorithm was presented that allows us to compute the values of the heat transfer coefficients for the secondary cooling zone. The correctness of the cooling parameter strategy was evaluated by inspecting the shell thickness, the length of the liquid core and the strand surface temperature. The ProCAST software package was used to construct the numerical model of continuous casting of steel.
All-solution-processed flexible thin film piezoelectric nanogenerator

Energy Technology Data Exchange (ETDEWEB)

Chung, Sung Yun; Kim, Sunyoung; Kim, Kyongjun [Program in Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-744 (Korea, Republic of); Lee, Ju-Hyuck; Kim, Sang-Woo [SKKU Advanced Institute of Nanotechnology, School of Advanced Materials Science and Engineering, Sungkyunkwan University (SKKU), Suwon 440-746 (Korea, Republic of); Kang, Chong-Yun; Yoon, Seok-Jin [Electronic Materials Center, Korea Institute of Science and Technology, Seoul 136-791 (Korea, Republic of); Kim, Youn Sang [Program in Nano Science and Technology, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 151-744 (Korea, Republic of); Advanced Institutes of Convergence Technology, 864-1 Iui-dong, Yeongtong-gu, Suwon-si, Gyeonggi-do 443-270 (Korea, Republic of)

2012-11-27

An all-solution-processed flexible thin film piezoelectric nanogenerator is demonstrated using reactive zinc hydroxo-condensation and a screen-printing method. The highly elastic thin film allows the piezoelectric energy to be generated through the mechanical rolling and muscle stretching of the piezoelectric unit. This flexible all solution-processed nanogenerator is promising for use in future energy harvesters such as wearable human patches and mobile electronics. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
Effect of the pressed ceramic filters on the reoxidation process

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Brůna Marek

2018-01-01

Full Text Available Article is focused on reoxidation processes during filtration of aluminium alloys. Many of our experiments proven, that when using filtration media in gating system, reoxidation occurs. Main goal of this article is to point out reoxidation problems occurring during filtration of aluminium alloys. Reason to conduct this work was anomalies discovered by experimental casts, which pointed out that after filtration of primary alloys, small oxide films was detected. Oxides was absent, when we poured without filtration media. Simulation software ProCAST was used during our research.
Colour Metallography of Cast Iron - Chapter 2: Grey Iron (Ⅱ

Directory of Open Access Journals (Sweden)

Zhou Jiyang

2009-08-01

Full Text Available Cast iron, as a traditional metal material, has advantages of low total cost, good castability and machinability, good wear resistance and low notch sensitivity, and is still facing tough challenge in quality, property and variety of types etc. Experts and engineers studying and producing iron castings all around world extremely concern this serious challenge. Over more than 30 years, a great of research work has been carried out on how to further improve its property, expand its application and combine cast iron technology with some hi-techs (for example, computer technology. Nevertheless, cast iron is a multi-element and multi-phase alloy and has complex and variety of structures and still has great development potential in structure and property. For further studying and developing cast iron, theoretical research work is important promise, and the study on solidification process and control mechanism of graphite morphology is fundamental for improving property of cast iron and developing new type of cast iron. Metallography of cast iron normally includes two sections: liquid phase transformation and solid phase transformation. The book, Colour Metallography of Cast Iron, uses colour metallography technique to study solidification structures of cast irons: graphite, carbides, austenite and eutectics; and focuses on solidification processes. With progress of modern solidification theory, the control of material solidification process becomes important measure for improving traditional materials and developing new materials. Solidification structure not only influences mechanical and physical properties of cast iron, but also affects its internal quality. The book uses a large amount of colour photos to describe the formation of solidification structures and their relations. Crystallization phenomena, which cannot be displayed with traditional metallography, are presented and more phase transformation information is obtained from these colour
Manufacturing technology of high-quality pressure castings

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S. Pietrowski

2011-10-01

Full Text Available The paper presents manufacturing technology of pressure castings made of Al-Si alloy without porosity or with low microporosity of castings. It has been shown that the greatest impact on the porosity of the castings and the concentration of hydrogen has had the charge to the melting furnace. Liquidation or occurrence of a small microporosity of castings provides refining with solid refiners, nitrogen and modification of liquid alloy after various operations of preparing process. The liquid alloy stored in holding furnace should be refined once every 2 h with nitrogen. Authors developed a computer program of Al-Si alloys inspection with using of TDA method. The developed technology was verified under production conditions.

Preparation and Characterization of Potentially Antimicrobial Polymer Films Containing Starch Nano- and Microparticles

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Paulius Pavelas DANILOVAS

2014-09-01

Full Text Available The forming conditions of biodegradable polymer films containing iodine-modified starch particles as well as the properties of the obtained films were investigated. Cationic cross-linked starch microparticles and cationic starch nanoparticles were dispersed in cellulose acetate and hydroxyethyl cellulose solution, respectively, and composite films were spin-casted. The obtained films were characterized and their mechanical properties were assessed. The cellulose acetate solution has been found to be an appropriate matrix for the dispersion of dry modified starch microparticles, but not in the case of nanoparticles. Starch nanoparticles were obtained in an aqueous medium, and the mechanical properties of the formed cellulose acetate films are significantly reduced by water present in the casting solution. It has been estimated that a fairly high amount of nanoparticles (18 wt% can be immobilized into films of water-soluble hydroxyethyl cellulose without markedly affecting the mechanical properties of the films. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.5426
BaF2 POST-DEPOSITION REACTION PROCESS FOR THICK YBCO FILMS

International Nuclear Information System (INIS)

SUENAGA, M.; SOLOVYOV, V.F.; WU, L.; WIESMANN, H.J.; ZHU, Y.

2001-01-01

The basic processes of the so-called BaF 2 process for the formation of YBa 2 Cu 3 O 7 , YBCO, films as well as its advantages over the in situ formation processes are discussed in the previous chapter. The process and the properties of YBCO films by this process were also nicely described in earlier articles by R. Feenstra, (et al.) Here, we will discuss two pertinent subjects related to fabrication of technologically viable YBCO conductors using this process. These are (1) the growth of thick (>> 1 microm) c-axis-oriented YBCO films and (2) their growth rates. Before the detail discussions of these subjects are given, we first briefly discuss what geometrical structure a YBCO-coated conductor should be. Then, we will provide examples of simple arguments for how thick the YBCO films and how fast their growth rates need to be. Then, the discussions in the following two sections are devoted to: (1) the present understanding of the nucleation and the growth process for YBCO, and why it is so difficult to grow thick c-axis-oriented films (> 3 microm), and (2) our present understanding of the YBCO growth-limiting mechanism and methods to increase the growth rates. The values of critical-current densities J c in these films are of primary importance for the applications,. and the above two subjects are intimately related to the control of J c of the films. In general, the lower the temperatures of the YBCO formation are the higher the values of J c of the films. Thus, the present discussion is limited to those films which are reacted at ∼735 C. This is the lowest temperature at which c-axis-oriented YBCO films (1-3 microm thick) are comfortably grown. It is also well known that the non-c-axis oriented YBCO platelets are extremely detrimental to the values of J c such that their effects on J c dwarf essentially all of other microstructural effects which control J c . Hence, the discussion given below is mainly focused on how to avoid the growth of these crystallites
Modeling and Analysis of The Pressure Die Casting Using Response Surface Methodology

International Nuclear Information System (INIS)

Kittur, Jayant K.; Herwadkar, T. V.; Parappagoudar, M. B.

2010-01-01

Pressure die casting is successfully used in the manufacture of Aluminum alloys components for automobile and many other industries. Die casting is a process involving many process parameters having complex relationship with the quality of the cast product. Though various process parameters have influence on the quality of die cast component, major influence is seen by the die casting machine parameters and their proper settings. In the present work, non-linear regression models have been developed for making predictions and analyzing the effect of die casting machine parameters on the performance characteristics of die casting process. Design of Experiments (DOE) with Response Surface Methodology (RSM) has been used to analyze the effect of effect of input parameters and their interaction on the response and further used to develop nonlinear input-output relationships. Die casting machine parameters, namely, fast shot velocity, slow shot to fast shot change over point, intensification pressure and holding time have been considered as the input variables. The quality characteristics of the cast product were determined by porosity, hardness and surface rough roughness (output/responses). Design of experiments has been used to plan the experiments and analyze the impact of variables on the quality of casting. On the other-hand Response Surface Methodology (Central Composite Design) is utilized to develop non-linear input-output relationships (regression models). The developed regression models have been tested for their statistical adequacy through ANOVA test. The practical usefulness of these models has been tested with some test cases. These models can be used to make the predictions about different quality characteristics, for the known set of die casting machine parameters, without conducting the experiments.
Microstructure and wear behavior of friction stir processed cast hypereutectic aluminum silicon

Directory of Open Access Journals (Sweden)

Ahmad Rosli

2017-01-01

Full Text Available Hypereutectic as-cast Al-18Si-Cu-Ni alloy was subjected to friction stir processing (FSP. The resultant effect of FSP on the alloy was evaluated by microstructure analysis and wear tests (dry sliding. A significant microstructural modification and enhancement in wear behavior of Al-18Si-Cu-Ni alloy was recorded after friction stir processing. Wear resistance improvement was related to considerable modification in size, morphology and distribution of silicon particles, and hardness improvement. It was found that lower tool rotation speed was more effective to refine silicon particles and in turn increase wear resistance. Minimum Si particle mean area of about 47.8 µm2, and wear rate of 0.0155 mg/m was achieved.
Bio-films and processes of bio-corrosion and bio-deterioration in oil-and gas-processing industry

Energy Technology Data Exchange (ETDEWEB)

Kholodenko, V.P.; Irkhina, I.A.; Chugunov, V.A.; Rodin, V.B.; Zhigletsova, S.K.; Yermolenko, Z.M.; Rudavin, V.V. [State Research Center for Applied Microbiology, Obolensk, Moscow region (Russian Federation)

2004-07-01

As a rule, oil- and gas-processing equipment and pipelines are attacked by different microorganisms. Their vital ability determines processes of bio-deterioration and bio-corrosion that lead often to technological accidents and severe environmental contamination. Bio-films presenting a complex association of different microorganisms and their metabolites are responsible for most of damages. In this context, to study the role bio-films may play in processes of bio-damages and in efficacy of protective measures is important. We have developed method of culturing bio-films on the surface of metal coupons by using a natural microbial association isolated from oil-processing sites. Simple and informative methods of determining microbiological parameters of bio-films required to study bio-corrosion processes are also developed. In addition, a method of electron microscopic analysis of bio-films and pitting corrosion is offered. Using these methods, we conducted model experiments to determine the dynamics of corrosion processes depending on qualitative and quantitative composition of bio-films, aeration conditions and duration of the experiment. A harmful effect of soil bacteria and micro-mycetes on different pipeline coatings was also investigated. Experiments were conducted within 3-6 months and revealed degrading action of microorganisms. This was confirmed by axial tension testing of coatings. All these approaches will be used for further development of measures to protect gas- and oil-processing equipment and pipelines against bio-corrosion and bio-damages (first of all biocides). (authors)
Development of non-dendritic microstructures in AA6061 cast billets

Energy Technology Data Exchange (ETDEWEB)

Zhang, X.-D.; Chadwick, T.A.; Bryant, J.D. [Reynolds Metals Co., Chester, VA (United States)

2000-07-01

Non-dendritic structures have been shown to have many advantages over conventional, dendritic structures in castable aluminum alloys. Examples include high structural integrity, reduced porosity, excellent formability and enhanced near net-shape forming capability. Non-dendritic materials are characterized by an equiaxed, globularized grain structure. Previous work has focused on the application of these structures in traditional casting alloys such as A356 and A357, and on the processing of these alloys during semi-solid forming and squeeze casting. There is considerably less information on the impact of non-dendritic microstructures upon solid state deformation, and the use of such microstructures in the processing of traditional wrought aluminum alloys. In this paper, we will present our recent work in casting non-dendritic AA6061 alloy using different techniques, and discuss the effects of cast structure on deformation behavior during solid state processing at elevated temperatures. Cast microstructures were modified during direct chill casting using three different methods: magneto-hydrodynamic (MHD) agitation, mechanical stirring, and high loadings of grain refiner. A detailed microstructure characterization will be presented and discussed in terms of structural integrity, grain morphology, and their effects on deformation in the solid state. (orig.)
The Effects of ZnOnanorodson the Characteristics of Sago Starch Biodegradable Films

Directory of Open Access Journals (Sweden)

R. Alebooyeh

2013-01-01

Full Text Available : Nowadays tend to use biodegradable packaging; including edible coatings and films for free from synthetic chemicals and do not cause environmental pollution, the industry is growing day by day. The aim of this research was to preparation and characterization of biodegradable films supported with ZnOnanorods. In this study, sago starch based films were prepared and plasticized with sorbitol/ glycerol by casting method. ZnOnanorod with 0, 1, 3and 5%(w/wwas added to the films before casting the films. Films were dried at controlled conditions. Physicochemical properties such as water absorption capacity (WAC, permeability to water vapor (WVP and water solubility of the films were measured. Also, the effects of addition of nano particles were measured on the antimicrobial properties of the films by agar diffusion method. Results showed that by increasing concentration of ZnOnanorod, solubility in water, WAC, and WVP of the films significantly (p <0.05 decreased. Furthermore, the addition of zinc oxide nanorods showed antimicrobial properties against E. Coli. In summary sago starch films supported with ZnOnanorodscan were used as active packaging for agricultural products as well as food industry.
Initial assessment of the processes and significance of thermal aging in cast stainless steels

International Nuclear Information System (INIS)

Chopra, O.K.; Chung, H.M.

1988-10-01

Charpy-impact and J-R curve data for thermally aged cast stainless steel are presented. The effects of material variables on the embrittlement of cast materials are evaluated. The chemical composition and ferrite morphology have a strong effect on the kinetics and extent of embrittlement. The procedure and correlations for predicting the impact strength and fracture toughness of cast component during reactor service are described. 19 refs., 17 figs., 4 tabs
ToxCast Workflow: High-throughput screening assay data processing, analysis and management (SOT)

Science.gov (United States)

US EPA’s ToxCast program is generating data in high-throughput screening (HTS) and high-content screening (HCS) assays for thousands of environmental chemicals, for use in developing predictive toxicity models. Currently the ToxCast screening program includes over 1800 unique c...
Determining casting defects in near-net shape casting aluminum parts by computed tomography

Science.gov (United States)

Li, Jiehua; Oberdorfer, Bernd; Habe, Daniel; Schumacher, Peter

2018-03-01

Three types of near-net shape casting aluminum parts were investigated by computed tomography to determine casting defects and evaluate quality. The first, second, and third parts were produced by low-pressure die casting (Al-12Si-0.8Cu-0.5Fe-0.9Mg-0.7Ni-0.2Zn alloy), die casting (A356, Al-7Si-0.3Mg), and semi-solid casting (A356, Al-7Si-0.3Mg), respectively. Unlike die casting (second part), low-pressure die casting (first part) significantly reduced the formation of casting defects (i.e., porosity) due to its smooth filling and solidification under pressure. No significant casting defect was observed in the third part, and this absence of defects indicates that semi-solid casting could produce high-quality near-net shape casting aluminum parts. Moreover, casting defects were mostly distributed along the eutectic grain boundaries. This finding reveals that refinement of eutectic grains is necessary to optimize the distribution of casting defects and reduce their size. This investigation demonstrated that computed tomography is an efficient method to determine casting defects in near-net shape casting aluminum parts.
Continuous manufacturing and analytical characterization of fixed-dose, multilayer orodispersible films.

Science.gov (United States)

Thabet, Yasmin; Lunter, Dominique; Breitkreutz, Joerg

2018-05-30

Various drug therapies require more than one active pharmaceutical ingredient (API) for an effective treatment. There are many advantages, e.g. to improve the compliance or pharmacodynamic response in comparison to a monotherapy or to increase the therapy safety. Until now, there are only a few products available for the paediatric population due to the lack of age appropriate dosage forms or studies proving the efficacy and safety of these products. This study aims to develop orodispersible films (ODFs) in a continuous solvent casting process as child appropriate dosage form containing both enalapril maleate (EM) and hydrochlorothiazide (HCT) separated in different film layers. Furthermore, they should be characterised and the API migration analysed by confocal Raman microscopy (CRM). ODFs were successfully produced in a continuous manufacturing process in form of double- and triple-layer formulations based on hydroxypropylcellulose (HPC) or a combination of HPC and polyvinyl alcohol (PVA). CRM revealed that both APIs migrate within the film layers shortly after manufacturing. PVA inhibits the migration inside the double-layer film, but is not able to prevent the API migration as an interlayer inside a triple-layer ODF. With increasing film layers, the content of residual solvents and the disintegration time increases (mono-layer films: processing two incompatible APIs. Copyright © 2018 Elsevier B.V. All rights reserved.
Grain Refinement of Permanent Mold Cast Copper Base Alloys

Energy Technology Data Exchange (ETDEWEB)

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

2005-04-01

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

Science.gov (United States)

Stewart, David J; Dalton, Matthew J; Swiger, Rachel N; Cooper, Thomas M; Haley, Joy E; Tan, Loon-Seng

2013-05-16

Spin-cast films of dyes (donor-π-donor, donor-π-acceptor, and acceptor-π-acceptor type, where the donor is Ph2N-, the acceptor is 2-benzothiazoyl, and the π-linker is 9,9-diethylfluorene) blended with nonconjugated bisphthalimides were prepared. Upon visible-light excitation of the dyes, quenching of the excited state occurs by exciplex formation between dye and bisphthalimide molecules or, in some cases, by excimer formation or aggregation-induced emission between two dye molecules. The extent of exciplex formation is dependent on the driving force, which can be calculated using the energy difference between the lowest unoccupied molecular orbitals (LUMOs) of the dyes and bisphthalimides. The results show that complete exciplex formation occurs when this driving force is greater than 0.57 eV whereas partial exciplex formation occurs when the driving force is between 0.28 and 0.57 eV. The exciplex emission energies can also be predicted by calculating the difference between the LUMO level of the bisphthalimide and the highest occupied molecular orbital (HOMO) of the dye. These calculated values, which were obtained from the electrochemically determined energy levels, showed good agreement with the observed emission energies. The exciplex lifetimes were found to be significantly longer than the lifetimes of the lone dyes. These exciplexes formed from nonlinked donors and acceptors in the solid state might have potential uses in nonlinear photonics.
Tips pentacene crystal alignment for improving performance of solution processed organic thin film transistors

Science.gov (United States)

He, Zhengran

A newly-developed p-type organic semiconductor 6,13-bis (triisopropylsilylethynyl) pentacene (TIPS pentacene) demonstrates various advantages such as high mobility, air stability and solution processibility, but at the same time its application is restricted by major issues, such as crystal misorientation and performance variation of organic thin-film transistors (OTFTs). This dissertation demonstrates several different approaches to address these issues. As a result, both crystal orientation and areal coverage can be effectively improved, leading to an enhancement of average mobility and performance consistency of OTFTs. Chapter 1 presents an introduction and background of this dissertation. Chapter 2 explores the usage of inorganic silica nanoparticles to manipulate the morphology of TIPS pentacene thin films and the performance of solution-processed organic OTFTs. The resultant drop-cast films yield improved morphological uniformity at ~10% SiO2 loading, which also leads to a 3-fold increase in average mobility and nearly 4-times reduction in the ratio of standard deviation of mobility (μStdev) to average mobility (μAvg). The experimental results suggest that the SiO2 nanoparticles mostly aggregate at TIPS pentacene grain boundaries, and that 10% nanoparticle concentration effectively reduces the undesirable crystal misorientation without considerably compromising TIPS pentacene crystallinity. Chapter 3 discusses the utilization of air flow to effectively reduce the TIPS pentacene crystal anisotropy and enhance performance consistency in OTFTs. Under air-flow navigation (AFN), TIPS pentacene forms thin films with improved crystal orientation and increased areal coverage, which subsequently lead to a four-fold increase of average hole mobility and one order of magnitude enhancement in performance consistency. Chapter 4 investigates the critical roles of lateral and vertical phase separation in the performance of the next-generation organic and hybrid electronic
The x-ray telescope of CAST

Energy Technology Data Exchange (ETDEWEB)

Kuster, M [Technische Universitaet Darmstadt, IKP, Schlossgartenstrasse 9, D-64289 Darmstadt (Germany); Braeuninger, H [Max-Planck-Institut fuer extraterrestrische Physik, Giessenbachstrasse, D-85748 Garching (Germany); Cebrian, S [Laboratorio de Fisica Nuclear y Altas Energias, Universidad de Zaragoza, E-50009 Zaragoza (Spain)] (and others)

2007-06-15

The CERN Axion Solar Telescope (CAST) has been 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 of magnitude is achieved, such that for the first time the axion photon coupling constant g{sub a{gamma}}{sub {gamma}} can be probed beyond the best astrophysical constraints g{sub a{gamma}}{sub {gamma}} < 1 x 10{sup -10} GeV{sup -1}.
Modeling and Analysis of Mechanical Properties of Aluminium Alloy (A413 Processed through Squeeze Casting Route Using Artificial Neural Network Model and Statistical Technique

Directory of Open Access Journals (Sweden)

R. Soundararajan

2015-01-01

Full Text Available Artificial Neural Network (ANN approach was used for predicting and analyzing the mechanical properties of A413 aluminum alloy produced by squeeze casting route. The experiments are carried out with different controlled input variables such as squeeze pressure, die preheating temperature, and melt temperature as per Full Factorial Design (FFD. The accounted absolute process variables produce a casting with pore-free and ideal fine grain dendritic structure resulting in good mechanical properties such as hardness, ultimate tensile strength, and yield strength. As a primary objective, a feed forward back propagation ANN model has been developed with different architectures for ensuring the definiteness of the values. The developed model along with its predicted data was in good agreement with the experimental data, inferring the valuable performance of the optimal model. From the work it was ascertained that, for castings produced by squeeze casting route, the ANN is an alternative method for predicting the mechanical properties and appropriate results can be estimated rather than measured, thereby reducing the testing time and cost. As a secondary objective, quantitative and statistical analysis was performed in order to evaluate the effect of process parameters on the mechanical properties of the castings.
Casting and stress-strain simulations of a cast ductile iron component using microstructure based mechanical behavior

International Nuclear Information System (INIS)

Olofsson, Jakob; Svensson, Ingvar L

2012-01-01

The industrial demand for increased component performance with concurrent reductions in component weight, development times and verifications using physical prototypes drives the need to use the full potential of casting and Finite Element Method (FEM) simulations to correctly predict the mechanical behavior of cast components in service. The mechanical behavior of the component is determined by the casting process, and factors as component geometry and casting process parameters are known to affect solidification and microstructure formation throughout the component and cause local variations in mechanical behavior as well as residual stresses. Though residual stresses are known to be an important factor in the mechanical behavior of the component, the importance of local mechanical behavior is not well established and the material is typically considered homogeneous throughout the component. This paper deals with the influence of solidification and solid state transformation on microstructure formation and the effect of local microstructure variations on the mechanical behavior of the cast component in service. The current work aims to investigate the coupling between simulation of solidification, microstructure and local variations in mechanical behavior and stress-strain simulation. This is done by performing several simulations of a ductile iron component using a recently developed simulation strategy, a closed chain of simulations for cast components, able to predict and describe the local variations in not only elastic but also plastic behavior throughout the component by using microstructural parameters determined by simulations of microstructural evolution in the component during the casting process. In addition the residual stresses are considered. The results show that the FEM simulation results are significantly affected by including microstructure based mechanical behavior. When the applied load is low and the component is subjected to stress levels
High oxygen nanocomposite barrier films based on xylan and nanocrystalline cellulose

Science.gov (United States)

Amit Saxena; Thomas J. Elder; Jeffrey Kenvin; Arthur J. Ragauskas

2010-01-01

The goal of this work is to produce nanocomposite film with low oxygen permeability by casting an aqueous solution containing xylan, sorbitol and nanocrystalline cellulose. The morphology of the resulting nanocomposite films was examined by scanning electron microscopy and atomic force microscopy which showed that control films containing xylan and sorbitol had a more...
Development and Characterization of Edible Films Based on Fruit and Vegetable Residues.

Science.gov (United States)

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

2016-02-01

Edible films were developed from the solid residue of the processing of whole fruits and vegetables. The solid residue, processed into flour (FVR flour) was chemically and structurally characterized by microstructure, elemental composition, structural links, and moisture sorption isotherm. Films were prepared by casting using aqueous extracts of 8% and 10% of flour (w/w) and characterized in terms of thickness, water solubility, mechanical properties, water vapor permeability, and Fourier transform infrared (FTIR). The analysis of microstructure and elemental composition, performed on flour (mean particle size 350 μm), showed an essentially granular aspect, with the presence of fibrous particles having potassium as one of the most abundant elements. FTIR results showed similarity between the characteristic bands of other raw materials used in edible films. The sorption isotherm of FVR flour showed a typical profile of foods rich in soluble components, such as sugars. Dried films presented an average thickness of 0.263 ± 0.003 mm, a homogenous aspect, bright yellow color, pronounced fruit flavor, and high water solubility. The FTIR spectra of the edible films revealed that addition of potato skin flour did not change the molecular conformation. Moreover, the films presented low tensile strength at break when compared with fruit starch-based films. © 2016 Institute of Food Technologists®
Marginal Accuracy of Castings Fabricated with Ringless Casting Investment System and Metal Ring Casting Investment System: A Comparative Study.

Science.gov (United States)

Kalavathi, M; Sachin, Bhuvana; Prasanna, B G; Shreeharsha, T V; Praveen, B; Ragher, Mallikarjuna

2016-02-01

The thermal expansion of the investment can be restricted by the metal casting ring because the thermal expansion of the ring is less than that of the investment. The ringless casting procedure is in use in clinical dentistry, though there is little scientific data to support its use in fixed partial dentures. In this study, marginal discrepancy of castings produced with the ringless casting technique and the conventional technique using the metal rings were compared. A total of 30 wax patterns were fabricated directly on a metal die. Optical stereomicroscope was used to measure the marginal discrepancy between the metal die and wax patterns. A total of 15 castings were invested using Bellavest T phosphate-bonded investment with the ringless technique and 15 were invested with the same investment with a metal ring; 30 castings were produced using a nickel-chromium ceramo-metal alloy. The internal surface of the castings was not modified and seated with finger pressure. The vertical marginal discrepancy was measured using an optical stereomicroscope at a magnification of 100x. The data obtained were statistically analyzed using students t-test (paired t-test and unpaired t-test). The castings of the ringless technique provided less vertical marginal discrepancy (240.56 ± 45.81 μ) than the castings produced with the conventional metal ring technique (281.98± 53.05 μ). The difference was statistically significant. The ringless casting technique had produced better marginal accuracy compared with conventional casting technique. Ringless casting system can be used routinely for clinical purpose.

An eco design strategy for high pressure die casting components: microstructural analysis applied to mass reducing processes

International Nuclear Information System (INIS)

Suarez-Pena, B.; Asensio-Lozano, J.

2009-01-01

In this work the study focused on the possibility of use of new aluminium alloys with optimized microstructures that ensure the mechanical properties requested for cast components made by high pressure die casting. The objective was to check the possibility of manufacture of structurally sound eco-steps for escalators with reduced structural integrity. The former arises as a result of a new redesign of the traditional steps aiming at a significant weight reduction. The experimental results show that it is feasible to cut the use of materials during processing and therefore to reduce the impact of the components during its lifetime, whilst the performance and safety standards are kept identical or even improved. (Author) 17 refs
Microstructural Evolution in Intensively Melt Sheared Direct Chill Cast Al-Alloys

Science.gov (United States)

Jones, S.; Rao, A. K. Prasada; Patel, J. B.; Scamans, G. M.; Fan, Z.

The work presented here introduces the novel melt conditioned direct chill casting (MC-DC) technology, where intensive melt shearing is applied to the conventional direct-chill casting process. MC-DC casting can successfully produce high quality Al-alloy billets. The results obtained from 80 mm diameter billets cast at speed of 200 mm/min show that MC-DC casting of Al-alloys, substantially refines the microstructure and reduces macro-segregation. In this paper, we present the preliminary results and discuss microstructural evolution during MC-DC casting of Al-alloys.
Process Modeling With Inhomogeneous Thin Films

Science.gov (United States)

Machorro, R.; Macleod, H. A.; Jacobson, M. R.

1986-12-01

Designers of optical multilayer coatings commonly assume that the individual layers will be ideally homogeneous and isotropic. In practice, it is very difficult to control the conditions involved in the complex evaporation process sufficiently to produce such ideal films. Clearly, changes in process parameters, such as evaporation rate, chamber pressure, and substrate temperature, affect the microstructure of the growing film, frequently producing inhomogeneity in structure or composition. In many cases, these effects are interdependent, further complicating the situation. However, this process can be simulated on powerful, interactive, and accessible microcomputers. In this work, we present such a model and apply it to estimate the influence of an inhomogeneous layer on multilayer performance. Presently, the program simulates film growth, thermal expansion and contraction, and thickness monitoring procedures, and includes the effects of uncertainty in these parameters or noise. Although the model is being developed to cover very general cases, we restrict the present discussion to isotropic and nondispersive quarterwave layers to understand the particular effects of inhomogeneity. We studied several coating designs and related results and tolerances to variations in evaporation conditions. The model is composed of several modular subprograms, is written in Fortran, and is executed on an IBM-PC with 640 K of memory. The results can be presented in graphic form on a monochrome monitor. We are currently installing and implementing color capability to improve the clarity of the multidimensional output.
Piezoelectric polydimethylsiloxane films for MEMS transducers

International Nuclear Information System (INIS)

Wang, Jhih-Jhe; Hsu, Tsung-Hsing; Yeh, Che-Nan; Tsai, Jui-Wei; Su, Yu-Chuan

2012-01-01

We have successfully demonstrated the fabrication of piezoelectric polydimethylsiloxane (PDMS) films utilizing multilayer casting, stacking, surface coating and micro plasma discharge processes. To realize the desired electromechanical sensitivity, cellular PDMS structures with micrometer-sized voids are implanted with bipolar charges on the opposite inner surfaces. The implanted charge pairs function as dipoles, which respond promptly to diverse electromechanical stimulation. In the prototype demonstration, cellular PDMS films with various void geometries are fabricated and internally coated with a thin layer of polytetrafluoroethylene, which can help secure the implanted charges. An electric field up to 35 MV m −1 is applied across the fabricated PDMS films to ionize the air in the voids and to accelerate the resulting bipolar charges to bombard the opposite inner surfaces. The resulting charge-implanted, cellular PDMS films show a low effective elastic modulus (E) of about 500 kPa, and a piezoelectric coefficient (d 33 ) higher than 300 pC N −1 , which is more than ten times higher than those of common piezoelectric polymers (e.g. polyvinylidene fluoride). Furthermore, the piezoelectricity of the PDMS films can be tailored by adjusting the dimensions of the cellular structures. As such, the demonstrated piezoelectric PDMS films could potentially serve as flexible and sensitive electromechanical materials, and fulfill the needs of a variety of sensor and energy harvesting applications. (paper)
Highly conductive, transparent flexible films based on open rings of multi-walled carbon nanotubes

International Nuclear Information System (INIS)

Ko, Wen-Yin; Su, Jun-Wei; Guo, Chian-Hua; Fu, Shu-Juan; Hsu, Chuen-Yuan; Lin, Kuan-Jiuh

2011-01-01

Open rings of multi-walled carbon nanotubes were stacked to form porous networks on a poly(ethylene terephthalate) substrate to form a flexible conducting film (MWCNT-PET) with good electrical conductivity and transparency by a combination of ultrasonic atomization and spin-coating technique. To enhance the electric flexibility, we spin-coated a cast film of poly(vinyl alcohol) onto the MWCNT-PET substrate, which then underwent a thermo-compression process. Field-emission scanning electron microscopy of the cross-sectional morphology illustrates that the film has a robust network with a thickness of ∼ 175 nm, and it remarkably exhibits a sheet resistance of approximately 370 Ω/sq with ∼ 77% transmittance at 550 nm even after 500 bending cycles. This electrical conductivity is much superior to that of other MWCNT-based transparent flexible films.
Modification of mechanical and thermal property of chitosan–starch blend films

International Nuclear Information System (INIS)

Tuhin, Mohammad O.; Rahman, Nazia; Haque, M.E.; Khan, Ruhul A.; Dafader, N.C.; Islam, Rafiqul; Nurnabi, Mohammad; Tonny, Wafa

2012-01-01

Chitosan–starch blend films (thickness 0.2 mm) of different composition were prepared by casting and their mechanical properties were studied. To improve the properties of chitosan–starch films, glycerol and mustard oil of different composition were used. Chitosan–starch films, incorporated with glycerol and mustard oil, were further modified with monomer 2-hydroxyethyl methacrylate (HEMA) using gamma radiation. The modified films showed improvement in both tensile strength and elongation at break than the pure chitosan–starch films. Water uptake of the films reduced significantly than the pure chitosan–starch film. Thermo gravimetric analysis (TGA) and dynamic mechanical analysis (DMA) showed that the modified films experience less thermal degradation than the pure films. Scanning electron microscopy (SEM) and FTIR were used to investigate the morphology and molecular interaction of the blend film, respectively. - Highlights: ► Chitosan–starch blend films (thickness 0.2 mm) were prepared by casting. ► To improve the properties of chitosan–starch films, glycerol and mustard oil of different composition were used. ► Chitosan–starch films, incorporated with glycerol and mustard oil, were further modified with monomer 2-hydroxyethyl methacrylate (HEMA) using gamma radiation. ► Properties of the modified films such as tensile strength, elongation at break, water uptake, TGA, DMA, SEM, FTIR were studied. ► Results indicate that modification of chitosan–starch film with mustard oil improved the properties of the blend films which could be further modified by HEMA using gamma radiation.
Densification effects on solution-processed indium-gallium-zinc-oxide films and their thin-film transistors

Energy Technology Data Exchange (ETDEWEB)

Rim, You Seung; Kim, Hyun Jae [School of Electrical and Electronic Engineering, Yonsei University, Seoul (Korea, Republic of)

2014-09-15

We report the effects of high-pressure annealing (HPA) on solution-processed InGaZnO (IGZO) thin-film transistors (TFTs). HPA increased the density of IGZO films. In particular, annealing in O{sub 2} at 1.0 MPa and 350 C resulted in a high-density and low-porosity IGZO film, as characterized using X-ray reflectivity (XRR) and ellipsometry measurements. This was attributed to the oxidative and compressive effects on the oxygen-deficient solution-processed IGZO film. TFTs annealed in O{sub 2} at 1.0 MPa and 350 C exhibited an increase in the field-effect mobility by a factor of approximately five compared with TFTs annealed in air at 0.1 MPa and 350 C. Furthermore, improvements in reliability under negative and positive bias stresses were also observed following HPA. (copyright 2014 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)
AIS/DOE Technology Roadmap Program: Strip Casting: Anticipating New Routes To Steel Sheet

Energy Technology Data Exchange (ETDEWEB)

Prof. Alan W. Camb; Prof. Anthony Rollett

2001-08-31

To determine the potential for strip casting in the steel industry and to develop the fundamental knowledge necessary to allow the role of strip casting in the modern steel industry to be understood. Based upon a study of carbon steel strip castings that were either produced for the program at British Steel or were received from a pre-commercial production machine, the following conclusions were made. Strip casting of carbon steels is technically feasible for sheet material from slightly less than 1 mm thick to 3 mm thick, and, assuming that it is economically viable, it will be first applied in carbon steel markets that do not require stringent surface quality or extensive forming. The potential of strip casting as a casting process to be developed for steel castings is very high as the cast strip has some very novel characteristics. Direct cast carbon strip has better surface quality, shape and profile than any other casting process currently available. The more rapidly solidified structure of direct cast strip tends to be strong with low ductility; however, with adequate thermal treatment, it is possible to develop a variety of properties from the same grade. The process is more amenable at this time to production tonnages per year of the order of 500,000 tons and as such will first find niche type applications. This technology is an additional technology for steel production and will be in addition to, rather than a replacement for, current casting machines.
The structure of oleamide films at the aluminum/oil interface and aluminum/air interface studied by Sum Frequency Generation (SFG) vibrational spectroscopy and Reflection Absorption Infrared Spectroscopy (RAIRS).

Science.gov (United States)

Casford, Michael T L; Davies, Paul B

2009-08-01

The structure of oleamide (cis-9-octadecenamide) films on aluminum has been investigated by sum frequency generation vibrational spectroscopy (SFG) and reflection absorption infrared spectroscopy (RAIRS). Three different film deposition strategies were investigated: (i) films formed by equilibrium adsorption from oleamide solutions in oil, (ii) Langmuir-Blodgett films cast at 1 and 25 mN m(-1), (iii) thick spin-cast films. Both L-B and spin-cast films were examined in air and under oil. The adsorbate formed in the 1 mN m(-1) film in air showed little orientational order. For this film, the spectroscopic results and the ellipsometric thickness point to a relatively conformationally disordered monolayer that is oriented principally in the plane of the interface. Direct adsorption to the metal interface from oil results in SFG spectra of oleamide that are comparable to those observed for the 1 mN m(-1) L-B film in air. In contrast, SFG and RAIRS results for the 25 mN m(-1) film in air and SFG spectra of the spin-cast film in air both show strong conformational ordering and orientational alignment normal to the interface. The 25 mN m(-1) film has an ellipsometric thickness almost twice that of the 1 mN m(-1) L-B film. Taken in combination with the spectroscopic results, this is indicative of a well packed monolayer in air in which the hydrocarbon chain is in an essentially defect-free extended conformation with the methyl terminus oriented away from the surface. A similar structure is also deduced for the surface of the spin-cast film in air. Upon immersion of the 25 mN m(-1) L-B film in oil the SFG spectra show that this film rapidly adopts a relatively disordered structure similar to that seen for the 1 mN m(-1) L-B film in air. Immersion of the spin-cast film in oil results in the gradual disordering of the amide film over a period of several days until the observed spectra become essentially identical to those observed for direct adsorption of oleamide from oil.
Travelling Through Caste

OpenAIRE

Kumar, Raj

2016-01-01

With its peculiar caste system, India is considered the most stratified of all known societies in human history. This system is ‘peculiar’ as it divides human beings into higher and lower castes and this division is backed by certain religious sanctions based on the sociological concepts of ‘purity’ and ‘pollution’. While the higher caste is associated with ‘purity’, the lower caste is associated with ‘pollution’. The people of the lower castes are not allowed to undertake religious journeys ...
Ponseti casting: a new soft option.

Science.gov (United States)

Brewster, M B S; Gupta, M; Pattison, G T R; Dunn-van der Ploeg, I D

2008-11-01

We have modified the Ponseti casting technique by using a below-knee Softcast instead of an above-knee plaster of Paris cast. Treatment was initiated as soon as possible after birth and the Pirani score was recorded at each visit. Following the manipulation techniques of Ponseti, a below-knee Softcast was applied directly over a stockinette for a snug fit and particular attention was paid to creating a deep groove above the heel to prevent slippage. If necessary, a percutaneous Achilles tenotomy was performed and casting continued until the child was fitted with Denis Browne abduction boots. Between April 2003 and May 2007 we treated 51 consecutive babies with 80 idiopathic club feet with a mean age at presentation of 4.5 weeks (4 days to 62 weeks). The initial mean Pirani score was 5.5 (3 to 6). It took a mean of 8.5 weeks (4 to 53) of weekly manipulation and casting to reach the stage of percutaneous Achilles tenotomy. A total of 20 feet (25%) did not require a tenotomy and for the 60 that did, the mean Pirani score at time of operation was 2.5 (0.5 to 3). Denis Browne boots were applied at a mean of 10 weeks (4 to 56) after presentation. The mean time from tenotomy to boots was 3.3 weeks (2 to 10). We experienced one case of cast-slippage during a period of non-attendance, which prolonged the casting process. One case of prolonged casting required repeated tenotomy, and three feet required repeated tenotomy and casting after relapsing while in Denis Browne boots. We believe the use of a below-knee Softcast in conjunction with Ponseti manipulation techniques shows promising initial results which are comparable to those using above-knee plaster of Paris casts.
Fabrication and Characterization of Porous MgAl₂O₄ Ceramics via a Novel Aqueous Gel-Casting Process.

Science.gov (United States)

Yuan, Lei; Liu, Zongquan; Liu, Zhenli; He, Xiao; Ma, Beiyue; Zhu, Qiang; Yu, Jingkun

2017-11-30

A novel and aqueous gel-casting process has been successfully developed to fabricate porous MgAl₂O₄ ceramics by using hydratable alumina and MgO powders as raw materials and deionized water as hydration agent. The effects of different amounts of deionized water on the hydration properties, apparent porosity, bulk density, microstructure, pore size distribution and compressive strength of the samples were investigated. The results indicated that the porosity and the microstructure of porous MgAl₂O₄ ceramics were governed by the amounts of deionized water added. The porous structure was formed by the liberation of physisorbed water and the decomposition of hydration products such as bayerite, brucite and boehmite. After determining the addition amounts of deionized water, the fabricated porous MgAl₂O₄ ceramics had a high apparent porosity (52.5-65.8%), a small average pore size structure (around 1-3 μm) and a relatively high compressive strength (12-28 MPa). The novel aqueous gel-casting process with easy access is expected to be a promising candidate for the preparation of Al₂O₃-based porous ceramics.
Effects of structural modification via high-pressure annealing on solution-processed InGaO films and thin-film transistors

International Nuclear Information System (INIS)

Rim, You Seung; Choi, Hyung-Wook; Kim, Kyung Hwan; Kim, Hyun Jae

2016-01-01

We investigated the structural modification of solution-processed nanocrystalline InGaO films via high-pressure annealing and fabricated thin-film transistors. The grain size of InGaO films annealed in the presence of oxygen under high pressure was significantly changed compared the films annealed without high pressure ambient. The O1s XPS peak distribution of InGaO films annealed under high pressure at 350 °C showed a peak similar to that of the non-pressure annealed film at 500 °C. The high-pressure annealing process promoted the elimination of organic residues and dehydroxylation of the metal hydroxide (M–OH) complex. We confirmed the improved device performance of high-pressure annealed InGaO-based thin-film transistors owing to the reduction in charge-trap density. (paper)
Fabrication of single nanofluidic channels in poly(methylmethacrylate) films via focused-ion beam milling for use as molecular gates

International Nuclear Information System (INIS)

Cannon, Donald M. Jr.; Flachsbart, Bruce R.; Shannon, Mark A.; Sweedler, Jonathan V.; Bohn, Paul W.

2004-01-01

Focused-ion beam (FIB) milling provides rapid fabrication of individual cylindrical submicrometer channels with reproducible dimensions (±5% diameters) through 8-μm thick poly(methylmethacrylate) (PMMA) films. PMMA films are spincast on sacrificial Si carriers and sputter-coated with Au before the 30-kV gallium FIB milling process. By adding a trace amount of poly(ethyleneoxide) and poly(dimethylsiloxane) to the PMMA solution before casting, the films can be released for subsequent mounting in microfluidic devices to create hybrid microfluidic-nanofluidic multilevel architectures. In situ FIB sectioning demonstrates the smooth cylindrical surface within the pore. Placing a milled film in contact with an aqueous fluorescein solution fills the channel by capillary action, as verified by confocal fluorescence microscopy. Confocal fluorescence of dyed films reveals that the pores span the thickness of the PMMA film. Small arrays of channels with a defined number and density and arbitrary in-plane spatial arrangement are fabricated with this process, allowing a unique testbed for high aspect ratio nanofluidic devices
Caste and power

DEFF Research Database (Denmark)

Roy, Dayabati

2011-01-01

This paper explores the institution of caste and its operation in a micro-level village setting of West Bengal, an Indian state, where state politics at grass roots level is vibrant with functioning local self-government and entrenched political parties. This ethnographic study reveals that caste...... relations and caste identities have overarching dimensions in the day-to-day politics of the study villages. Though caste almost ceases to operate in relation to strict religious strictures, under economic compulsion the division of labour largely coincides with caste division. In the cultural......–ideological field, the concept of caste-hierarchy seems to continue as an influencing factor, even in the operation of leftist politics....
Thin-Film Materials Synthesis and Processing Facility

Data.gov (United States)

Federal Laboratory Consortium — FUNCTION: Provides a wide capability for deposition and processing of thin films, including sputter and ion-beam deposition, thermal evaporation, electro-deposition,...
Quality control procedure for dental x-ray film processing

International Nuclear Information System (INIS)

Tingey, D.R.C.

1983-08-01

Methods of obtaining the optimum processing from dental films are discussed. A method of quality control of developing conditions for dental x-ray films has been developed. It is relatively easy to maintain and is sufficiently accurate for practical purposes
The effect of formulation additives on the properties of films prepared ...

African Journals Online (AJOL)

Method: Films were prepared by solvent casting method using Terminalia, xanthan gums and hydroxylpropy lmethylcellulose (HPMC). Terminlia was also combined with xanthan, HPMC at different ratios using propylene glycol and glycerol as plaasticizers. The films were characterized using adherence, folding endurance ...
The Cracking Mechanism of Ferritic-Austenitic Cast Steel

Directory of Open Access Journals (Sweden)

Stradomski G.

2016-12-01

Full Text Available In the high-alloy, ferritic - austenitic (duplex stainless steels high tendency to cracking, mainly hot-is induced by micro segregation processes and change of crystallization mechanism in its final stage. The article is a continuation of the problems presented in earlier papers [1 - 4]. In the range of high temperature cracking appear one mechanism a decohesion - intergranular however, depending on the chemical composition of the steel, various structural factors decide of the occurrence of hot cracking. The low-carbon and low-alloy cast steel casting hot cracking cause are type II sulphide, in high carbon tool cast steel secondary cementite mesh and / or ledeburite segregated at the grain solidified grains boundaries, in the case of Hadfield steel phosphorus - carbide eutectic, which carrier is iron-manganese and low solubility of phosphorus in high manganese matrix. In duplex cast steel the additional factor increasing the risk of cracking it is very “rich” chemical composition and related with it processes of precipitation of many secondary phases.
Energy Saving Melting and Revert Reduction Technology: Improved Die Casting Process to Preserve the Life of the Inserts

Energy Technology Data Exchange (ETDEWEB)

David Schwam, PI; Xuejun Zhu, Sr. Research Associate

2012-09-30

The goal of this project was to study the combined effects of die design, proper internal cooling and efficient die lubricants on die life. The project targeted improvements in die casting insert life by: Optomized Die Design for Reduced Surface Temperature: The life of die casting dies is significantly shorter when the die is exposed to elevated temperature for significant periods of time. Any die operated under conditions leading to surface temperature in excess of 1050oF undergoes structural changes that reduce its strength. Optimized die design can improve die life significantly. This improvement can be accomplished by means of cooling lines, baffles and bubblers in the die. A key objective of the project was to establish criteria for the minimal distance of the cooling lines from the surface. This effort was supported with alloys and machining by BohlerUddeholm, Dunn Steel, HH Stark and Rex Buckeye. In plant testing and evaluation was conducted as in-kind cost share at St. Clair Die Casting. The Uddeholm Dievar steel evaluated in this program showed superior resistance to thermal fatigue resistance. Based on the experimental evidence, cooling lines could be placed as close as 0.5"Â from the surface. Die Life Extension by Optimized Die Lubrication: The life of die casting dies is affected by additions made to its surface with the proper lubricants. These lubricants will protect the surface from the considerable temperature peaks that occur when the molten melt enters the die. Dies will reach a significantly higher temperature without this lubricant being applied. The amount and type of the lubricant are critical variables in the die casting process. However, these lubricants must not corrode the die surface. This effort was supported with alloys and machining by BohlerUddeholm, Dunn Steel, HH Stark and Rex Buckeye. In plant testing and evaluation was conducted as in-kind cost share at St. Clair Die Casting. Chem- Trend participated in the program with die

Use of a general-purpose heat-transfer code for casting simulation

International Nuclear Information System (INIS)

Erickson, W.C.

1975-07-01

The practical use of numerical techniques in simulating casting solidification dictate that a general purpose heat transfer code be used and that results be obtained in an easy-to-analyze format. Color film plotting routines were developed for use with NASA's CINDA-3G heat transfer code; the combination of which meet the above criteria. The subroutine LQSLTR written for SINDA, the successor to CINDA-3G, was verified by comparing calculated results obtained using LQSLTR with those obtained using the specific heat method for handling the heat of fusion. Excellent agreement existed when similar data was used. When the more restrictive requirement of a 1 0 F melting range was used, comparable results were obtained. Uranium and lead rod castings were cast in instrumented graphite molds and the solidification sequence simulated using CINDA-3G. Discrepancies attributed to initial assumptions of instantaneous mold filling, uniform melt temperature, and intimate metal/mold contact were encountered. Further calculations using a model incorporating a gap between the mold and casting showed that the intimate contact assumption could not be used; a three-dimensional model also showed that the thermocouple assemblies used with the platinum--platinum-10 percent rhodium were a significant perturbation to the system. An L-shaped steel casting was simulated and the results compared to those reported in the literature. The experimental data for this casting were reproduced within the accuracy permitted by the thermal conductivity of the sand, thus demonstrating that agreement can be obtained when the mold material does not act as a chill. (U.S.)
Effect of sodium sulfite, sodium dodecyl sulfate, and urea on the molecular interactions and properties of whey protein isolate-based films

Science.gov (United States)

Schmid, Markus; Prinz, Tobias K.; Stäbler, Andreas; Sängerlaub, Sven

2016-12-01

Whey protein coatings and cast films are promising for use as food packaging materials. Ongoing research is endeavoring to reduce their permeability. The intention of this study was to evaluate the effect of the reactive additives sodium sulfite, sodium dodecyl sulfate (SDS), and urea on the oxygen barrier, water vapor barrier, and protein solubility of whey protein cast films. The concentration of the reactive additives was 1 to 20 wt.-%. Dried whey protein cast films were used as substrate materials. The water vapor transmission rate, the oxygen permeability, and the protein solubility were measured. Effective diffusion coefficients and effective sorption coefficients were calculated from the results of the water vapor sorption experiments. The presence of sodium sulfite resulted in an increased number of hydrophobic interactions and hydrogen bonds and a slightly decreased number of disulfide bonds. The oxygen permeability decreased from 68 to 46 cm³ (STP / standard temperature and pressure) 100 µm (m² d bar)-1 for 1 wt.-% SDS in the whey protein cast film. The water vapor transmission rate decreased from 165 to 44 g 100 µm (m² d)-1 measured at 50 to 0 % r. h. for 20 wt.-% SDS in the whey protein cast film. The reduction in the water vapor transmission rate correlated with the lower effective diffusion coefficient.
Energy Saving Melting and Revert Reduction Technology (Energy-SMARRT): Light Metals Permanent Mold Casting

Energy Technology Data Exchange (ETDEWEB)

Fasoyinu, Yemi [CanmetMATERIALS

2014-03-31

Current vehicles use mostly ferrous components for structural applications. It is possible to reduce the weight of the vehicle by substituting these parts with those made from light metals such as aluminum and magnesium. Many alloys and manufacturing processes can be used to produce these light metal components and casting is known to be most economical. One of the high integrity casting processes is permanent mold casting which is the focus of this research report. Many aluminum alloy castings used in automotive applications are produced by the sand casting process. Also, aluminum-silicon (Al-Si) alloys are the most widely used alloy systems for automotive applications. It is possible that by using high strength aluminum alloys based on an aluminum-copper (Al-Cu) system and permanent mold casting, the performance of these components can be enhanced significantly. This will also help to further reduce the weight. However, many technological obstacles need to be overcome before using these alloys in automotive applications in an economical way. There is very limited information in the open literature on gravity and low-pressure permanent mold casting of high strength aluminum alloys. This report summarizes the results and issues encountered during the casting trials of high strength aluminum alloy 206.0 (Al-Cu alloy) and moderate strength alloy 535.0 (Al-Mg alloy). Five engineering components were cast by gravity tilt-pour or low pressure permanent mold casting processes at CanmetMATERIALS (CMAT) and two production foundries. The results of the casting trials show that high integrity engineering components can be produced successfully from both alloys if specific processing parameters are used. It was shown that a combination of melt processing and mold temperature is necessary for the elimination of hot tears in both alloys.
AN INTRODUCTION TO RAPID CASTING: DEVELOPMENT AND INVESTIGATION OF PROCESS CHAINS FOR SAND CASTING OF FUNCTIONAL PROTOTYPES

Directory of Open Access Journals (Sweden)

D. Dimitrov

2012-01-01

Full Text Available
ENGLISH ABSTRACT: This paper discusses the results obtained from studies on different Rapid Tooling process chains in order to improve the design and manufacture of foundry equipment that is used for sand casting of prototypes in final material. These prototypes are intended for functional and pre-production tests of vehicles. The Three Dimensional Printing process is used as core technology. Subsequently, while considering aspects such as time, cost, quality (accuracy and surface roughness, and tool life, a framework is presented for the evaluation and selection of the most suitable process chain in accordance with specific requirements. This research builds on an in-depth characterisation of the accuracy and repeatability of a 3D printing process.
AFRIKAANSE OPSOMMING: Hierdie artikel bespreek die resultate wat verkry is tydens studies op verskillende Snel-Gereedskapvervaardigingproseskettings wat ondersoek is teneinde die ontwerp en vervaardiging van sandgietgereedskap, om prototipes in finale materiaal te vervaardig, te verbeter. Die prototipes is bestem vir gebruik in funksionele- en voorproduksietoetse van voertuie. Die sogenaamde Driedimensionele Drukproses (3DP is as kerntegnologie aangewend. Gevolglik, na oorweging van aspekte soos tyd, koste, kwaliteit (akkuraatheid en oppervlakafwerking, en gereedskapleeftyd, is ’n raamwerk ontwikkel vir die evaluering en seleksie van die mees geskikte prosesketting met inagname van spesifieke vereistes. Hierdie navorsing bou op ’n diepgaande karakterisering van die akkuraatheids- en herhaalbaarheidsvermoë van ’n 3D drukproses.
Data Package for Secondary Waste Form Down-Selection-Cast Stone

International Nuclear Information System (INIS)

Serne, R. Jeffrey; Westsik, Joseph H.

2011-01-01

Available literature on Cast Stone and Saltstone was reviewed with an emphasis on determining how Cast Stone and related grout waste forms performed in relationship to various criteria that will be used to decide whether a specific type of waste form meets acceptance criteria for disposal in the Integrated Disposal Facility (IDF) at Hanford. After the critical review of the Cast Stone/Saltstone literature, we conclude that Cast Stone is a good candidate waste form for further consideration. Cast stone meets the target IDF acceptance criteria for compressive strength, no free liquids, TCLP leachate are below the UTS permissible concentrations and leach rates for Na and Tc-99 are suiteably low. The cost of starting ingredients and equipment necessary to generate Cast Stone waste forms with secondary waste streams are low and the Cast Stone dry blend formulation can be tailored to accommodate variations in liquid waste stream compositions. The database for Cast Stone short-term performance is quite extensive compared to the other three candidate waste solidification processes. The solidification of liquid wastes in Cast Stone is a mature process in comparison to the other three candidates. Successful production of Cast Stone or Saltstone has been demonstrated from lab-scale monoliths with volumes of cm3 through m3 sized blocks to 210-liter sized drums all the way to the large pours into vaults at Savannah River. To date over 9 million gallons of low activity liquid waste has been solidified and disposed in concrete vaults at Savannah River.
Data Package for Secondary Waste Form Down-Selection—Cast Stone

Energy Technology Data Exchange (ETDEWEB)

Serne, R. Jeffrey; Westsik, Joseph H.

2011-09-05

Available literature on Cast Stone and Saltstone was reviewed with an emphasis on determining how Cast Stone and related grout waste forms performed in relationship to various criteria that will be used to decide whether a specific type of waste form meets acceptance criteria for disposal in the Integrated Disposal Facility (IDF) at Hanford. After the critical review of the Cast Stone/Saltstone literature, we conclude that Cast Stone is a good candidate waste form for further consideration. Cast stone meets the target IDF acceptance criteria for compressive strength, no free liquids, TCLP leachate are below the UTS permissible concentrations and leach rates for Na and Tc-99 are suiteably low. The cost of starting ingredients and equipment necessary to generate Cast Stone waste forms with secondary waste streams are low and the Cast Stone dry blend formulation can be tailored to accommodate variations in liquid waste stream compositions. The database for Cast Stone short-term performance is quite extensive compared to the other three candidate waste solidification processes. The solidification of liquid wastes in Cast Stone is a mature process in comparison to the other three candidates. Successful production of Cast Stone or Saltstone has been demonstrated from lab-scale monoliths with volumes of cm3 through m3 sized blocks to 210-liter sized drums all the way to the large pours into vaults at Savannah River. To date over 9 million gallons of low activity liquid waste has been solidified and disposed in concrete vaults at Savannah River.
Controlled release of tetracycline-HCl from halloysite-polymer composite films.

Science.gov (United States)

Ward, Christopher J; Song, Shang; Davis, Edward W

2010-10-01

The first direct comparison between two common methods for loading halloysite with a small molecule for controlled release is presented. While the methods differ in the degree of simplicity, they provide essentially the same level of loading and release kinetics. A tentative explanation of the "burst" effect often seen in the release of low molecular weight molecules from halloysite is provided. The ability of halloysite to mediate the release rate of a water soluble drug, tetracycline, from solution cast polyvinyl alcohol and polymethyl methacrylate films was evaluated. In some films, montmorillonite was also incorporated. The addition of montmorillonite to solutions used to cast tetracycline containing films significantly reduced the release rate from the dried films. The same overall effect was seen when the drug was loaded into halloysite prior to preparation of the films. In both cases, the release was best fit with the simple Higuchi model. However, when montmorillonite was added to solutions of polyvinyl alcohol and drug loaded halloysite the release profiles were better fit by the Ritgar-Peppas model for anomalous transport. Release from polymethyl methacrylate was reduced by a factor of three by incorporating the drug in halloysite prior to producing the films.
Technological Aspects of Low-Alloyed Cast Steel Massive Casting Manufacturing

Directory of Open Access Journals (Sweden)

Szajnara J.

2013-12-01

Full Text Available In the paper authors have undertaken the attempt of explaining the causes of cracks net occurrence on a massive 3-ton cast steel casting with complex geometry. Material used for casting manufacturing was the low-alloyed cast steel with increased wear resistance modified with vanadium and titanium. The studies included the primary and secondary crystallization analysis with use of TDA and the qualitative and quantitative analysis of non-metallic inclusions.
Solution processed pentacene thin films and their structural properties

International Nuclear Information System (INIS)

Tao Chunlan; Zhang Xuhui; Zhang Fujia; Liu Yiyang; Zhang Haoli

2007-01-01

The paper reported the solution process of pentacene thin films from organic solvent O-dichlorobenzene. The pentacene thin films obtained from different conditions were characterized by X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM), and UV-vis spectroscopy. The result shows that the pentacene solution was successfully obtained at a minimum temperature of 40 deg. C. The optimum temperature of forming pentacene thin films was 100 deg. C
Biopolymer films to control fusarium dry rot and their application to preserve potato tubers

Science.gov (United States)

Films were cast using sodium alginate (NaAlg), high molecular weight (HMW) chitosan, and low molecular weight (LMW) chitosan as film forming biopolymers. Fludioxonil (Fl) at 1% concentration was used as fungicide. Thermal stability, mechanical, and water sorption properties of the films were examine...
Gangs and guilt: Towards a new theory of horror film

OpenAIRE

Kord, S. T.

2016-01-01

The most basic and unanimous statement made in scholarship on horror films is that horror films are ‘about’ fear: the primary purpose of horror films is to scare viewers. Based on horror films from the 1970s until the present in which child gangs play a significant part, this essay advances a new theory of horror film, namely that horror films primarily seek to elicit not fear but guilt. The analysis focuses on four topics: themes, camera angles, horror’s cinematic casting of ‘abnormality,’ a...
Friction welding of ductile cast iron using interlayers

International Nuclear Information System (INIS)

Winiczenko, Radoslaw; Kaczorowski, Mieczyslaw

2012-01-01

Highlights: → The results of the study of the friction welding of ductile cast iron using interlayers are presented. → The results of the analysis shows that the joint has the tensile strength compared to that of basic material. → In case of ductile cast iron, it is possible to reach the tensile strength equals even 700 MPa. → The process of friction welding was accompanied with diffusion of Cr, Ni and C atoms across the interface. -- Abstract: In this paper, ductile cast iron-austenitic stainless steel, ductile cast iron-pure Armco iron and ductile cast iron-low carbon steel interlayers were welded, using the friction welding method. The tensile strength of the joints was determined, using a conventional tensile test machine. Moreover, the hardness across the interface of materials was measured on metallographic specimens. The fracture surface and microstructure of the joints was examined using either light stereoscope microscopy as well as electron microscopy. In this case, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were applied. The results of the analysis shows that the joint has the tensile strength compared to that of basic material. In case of ductile cast iron, it is possible to reach the tensile strength equals even 700 MPa. It was concluded that the process of friction welding was accompanied with diffusion of Cr, Ni and C atoms across the ductile cast iron-stainless steel interface. This leads to increase in carbon concentration in stainless steel where chromium carbides were formed, the size and distribution of which was dependent on the distance from the interface.
Etching processes of transparent carbon nanotube thin films using laser technologies

International Nuclear Information System (INIS)

Lin, H.K.; Lin, R.C.; Li, C.H.

2010-01-01

Carbon nanotubes (CNTs) have potential as a transparent conductive material with good mechanical and electrical properties. However, carbon nanotube thin film deposition and etching processes are very difficult to pattern the electrode. In this study, transparent CNT film with a binder is coated on a PET flexible substrate. The transmittance and sheet resistance of carbon nanotube film are 84% and 1000 Ω/□, respectively. The etching process of carbon nanotube film on flexible substrates was investigated using 355 nm and 1064 nm laser sources. Experimental results show that carbon nanotube film can be ablated using laser technology. With the 355 nm UV laser, the minimum etched line width was 20 μm with a low amount of recast material of the ablated sections. The optimal conditions of laser ablation were determined for carbon nanotube film.
Reducing the Incidence of Cast-related Skin Complications in Children Treated With Cast Immobilization.

Science.gov (United States)

Difazio, Rachel L; Harris, Marie; Feldman, Lanna; Mahan, Susan T

2017-12-01

Cast immobilization remains the mainstay of pediatric orthopaedic care, yet little is known about the incidence of cast-related skin complications in children treated with cast immobilization. The purposes of this quality improvement project were to: (1) establish a baseline rate of cast-related skin complications in children treated with cast immobilization, (2) identify trends in children who experienced cast-related skin complications, (3) design an intervention aimed at decreasing the rate of cast-related skin complications, and (4) determine the effectiveness of the intervention. A prospective interrupted time-series design was used to determine the incidence of cast-related skin complications overtime and compare the rates of skin complications before and after an intervention designed to decrease the incidence of cast-related heel complications. All consecutive patients who were treated with cast immobilization from September 2012 to September 2014 were included. A cast-related skin complications data collection tool was used to capture all cast-related skin complications. A high rate of heel events was noted in our preliminary analysis and an intervention was designed to decrease the rate of cast-related skin complications, including the addition of padding during casting and respective provider education. The estimated cast-related skin events rate for all patients was 8.9 per 1000 casts applied. The rate for the total preintervention sample was 13.6 per 1000 casts which decreased to 6.6 in the postintervention sample. When examining the heel-only group, the rate was 17.1 per 1000 lower extremity casts applied in the preintervention group and 6.8 in the postintervention group. Incorporating padding to the heel of lower extremity cast was an effective intervention in decreasing the incidence of cast-related skin complications in patients treated with cast immobilization. Level II.
"Split Cast Mounting: Review and New Technique".

Science.gov (United States)

Gundawar, S M; Pande, Neelam A; Jaiswal, Priti; Radke, U M

2014-12-01

For the fabrication of a prosthesis, the Prosthodontist meticulously performs all the steps. The laboratory technician then make every effort/strives to perform the remaining lab procedures. However when the processed dentures are remounted on the articulator, some changes are seen. These changes may be divided into two categories: Pre-insertion and post-insertion changes, which deal with the physical properties of the materials involved (Parker, J Prosthet Dent 31:335-342, 1974). Split cast mounting is the method of mounting casts on the articulator. It is essentially a maxillary cast constructed in two parts with a horizontal division. The procedure allows for the verification of the accuracy of the initial mounting and the ease of removal and replacement of the cast. This provides a precise means of correcting the changes in occlusion occurring as a result of the processing technique (Nogueira et al., J Prosthet Dent 91:386-388, 2004). Instability of the split mounting has always been a problem to the Prosthodontist thereby limiting its use. There are various materials mentioned in the literature. The new technique by using Dowel pins and twill thread is very easy, cheaper and simple way to stabilize the split mounting. It is useful and easy in day to day laboratory procedures. The article presents different methods of split cast mounting and the new procedure using easily available materials in prosthetic laboratory.
Characterization of magnetization processes in nanostructured rare earth-transition metal films

International Nuclear Information System (INIS)

Zheng Guangping; Zhan Yangwen; Liu Peng; Li Mo

2003-01-01

We synthesize rare earth-transition metal (RE-TM) amorphous films using the electrodeposition method (RE=Nd, Gd and TM=Co). Nanocrystructured RE-TM films are prepared by thermal treatment of as-synthesized films below the glass-crystal transition temperature. Based on the magnetoelastic effect, the magnetization processes in nanostructured samples are characterized by acoustic internal friction measurements using the vibrating-reed technique. Since internal friction and the Young's modulus are sensitive to grain boundary and magnetic domains movement, this technique seems to characterize the effects of nanostructures on the magnetization processes in RE-TM films well. We find that the magnetoelastic effect in nanostructured RE-TM film increases with an increase in grain size
Transparent megahertz circuits from solution-processed composite thin films.

Science.gov (United States)

Liu, Xingqiang; Wan, Da; Wu, Yun; Xiao, Xiangheng; Guo, Shishang; Jiang, Changzhong; Li, Jinchai; Chen, Tangsheng; Duan, Xiangfeng; Fan, Zhiyong; Liao, Lei

2016-04-21

Solution-processed amorphous oxide semiconductors have attracted considerable interest in large-area transparent electronics. However, due to its relative low carrier mobility (∼10 cm(2) V(-1) s(-1)), the demonstrated circuit performance has been limited to 800 kHz or less. Herein, we report solution-processed high-speed thin-film transistors (TFTs) and integrated circuits with an operation frequency beyond the megahertz region on 4 inch glass. The TFTs can be fabricated from an amorphous indium gallium zinc oxide/single-walled carbon nanotube (a-IGZO/SWNT) composite thin film with high yield and high carrier mobility of >70 cm(2) V(-1) s(-1). On-chip microwave measurements demonstrate that these TFTs can deliver an unprecedented operation frequency in solution-processed semiconductors, including an extrinsic cut-off frequency (f(T) = 102 MHz) and a maximum oscillation frequency (f(max) = 122 MHz). Ring oscillators further demonstrated an oscillation frequency of 4.13 MHz, for the first time, realizing megahertz circuit operation from solution-processed semiconductors. Our studies represent an important step toward high-speed solution-processed thin film electronics.
Functional chitosan-based grapefruit seed extract composite films for applications in food packaging technology

International Nuclear Information System (INIS)

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

2015-01-01

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

Energy Technology Data Exchange (ETDEWEB)

Tan, Y.M. [Department of Mechanical Engineering, National University of Singapore (Singapore); Lim, S.H.; Tay, B.Y. [Forming Technology Group, Singapore Institute of Manufacturing Technology (Singapore); Lee, M.W. [Food Innovation and Resource Centre, Singapore Polytechnic (Singapore); Thian, E.S., E-mail: mpetes@nus.edu.sg [Department of Mechanical Engineering, National University of Singapore (Singapore)

2015-09-15

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

International Nuclear Information System (INIS)

Nguyen, Chuong L.; Atanacio, Armand; Zhang, Wei; Prince, Kathryn E.; Hyland, Margaret M.; Metson, James B.

2009-01-01

There have been many reports of the surface segregation of minor elements, especially Mg, into surface layers and oxide films on the surface of Al alloys. LM6 casting alloy (Al-12%Si) represents a challenging system to examine such segregation as the alloy features a particularly inhomogeneous phase structure. The very low but mobile Mg content (approximately 0.001 wt.%), and the surface segregation of modifiers such as Na, mean the surface composition responds in a complex manner to thermal treatment conditions. X-ray photoelectron spectroscopy (XPS) has been used to determine the distribution of these elements within the oxide film. Further investigation by dynamic secondary ion mass spectrometry (DSIMS) confirmed a strong alignment of segregated Na and Mg into distinct phases of the structure.

PVD processes of thin films deposition using Hall-current discharge

International Nuclear Information System (INIS)

Svadkovskij, I.V.

2007-01-01

Results of research and developments in the field of PVD processes of thin films deposition using Hall-current discharge have been summarized. Effects of interaction of ions with surface during deposition have been considered. Also features of application and prospects of devices based on ion beam and magnetron sputtering systems in thin films technologies have been analyzed. The aspects in the field plasma physics, technology and equipment plasma PVD processes of thin films deposition have been systematized, on the base of investigations made by author and other scientists. (authors)
Casting materials and their application in research and teaching.

Science.gov (United States)

Haenssgen, Kati; Makanya, Andrew N; Djonov, Valentin

2014-04-01

From a biological point of view, casting refers to filling of anatomical and/or pathological spaces with extraneous material that reproduces a three-dimensional replica of the space. Casting may be accompanied by additional procedures such as corrosion, in which the soft tissue is digested out, leaving a clean cast, or the material may be mixed with radiopaque substances to allow x-ray photography or micro computed topography (µCT) scanning. Alternatively, clearing of the surrounding soft tissue increases transparency and allows visualization of the casted cavities. Combination of casting with tissue fixation allows anatomical dissection and didactic surgical procedures on the tissue. Casting materials fall into three categories namely, aqueous substances (India ink, Prussian blue ink), pliable materials (gelatins, latex, and silicone rubber), or hard materials (methyl methacrylates, polyurethanes, polyesters, and epoxy resins). Casting has proved invaluable in both teaching and research and many phenomenal biological processes have been discovered through casting. The choice of a particular material depends inter alia on the targeted use and the intended subsequent investigative procedures, such as dissection, microscopy, or µCT. The casting material needs to be pliable where anatomical and surgical manipulations are intended, and capillary-passable for ultrastructural investigations.
Centrifugal Casting Features/Metallurgical Characterization of Aluminum Alloys

International Nuclear Information System (INIS)

Chirita, G.; Soares, D.; Cruz, D.; Silva, F. S.; Stefanescu, I.

2008-01-01

This paper deals with the study of centrifugal effects on aluminium castings under high G values. Most of the studies in this domain (FGMs obtained by centrifugal casting) deal with functionally graded composites reinforced with a solid phase such as silicon particles or others. However, in this study it will be shown that unreinforced aluminium alloys may be significantly influenced by the centrifugal effect and that functionally graded castings are also obtained. It has been observed that the centrifugal effect may increase in some alloys, depending on the relative position in the castings, the rupture strength by approx. 50%, and rupture strain by about 300%, as compared to the gravity casting technique. The Young's modulus may also increase by about 20%. It has also been reported that in vertical centrifugal castings there are mainly three aspects that affect the components thus obtained, namely: fluid dynamics; vibration (inherent to the system); and centrifugal force. These features have a different effect on the castings depending on the aluminium alloy. In this paper, an analysis of the most important effects of the centrifugal casting process on metallurgical features is conducted. A solidification characterization at several points along the mould will be made in order to have an accurate idea of both the fluid dynamics inside the mould during the casting and the solidification behavior in different parts of the component. These two analyses will be related to the metallurgical properties (phase distribution; SDAS; eutectic silicon content and shape, pores density and shape) along the component and mainly along the direction of the centrifugal pressure. A comparison between castings obtained by both centrifugal casting technique and gravity casting technique is made for reference (gravity casting)
Modelling and multi objective optimization of LM13 aluminium alloy squeeze cast process parameters using taguchi and genetic algorithm

Directory of Open Access Journals (Sweden)

S. Vellingiri

2018-01-01

Full Text Available This present investigation deals with squeeze casting process in order to produce a component with good mechanical properties such as micro-hardness(VH, tensile strength(Rm, and density(ρ on LM13 by varying squeeze pressure(P, molten temperature(Tm and die temperature(Td. Taguchi experimental design L9 orthogonal array was used to determine the signal to noise ratio. The results specified that the squeeze pressure and die preheat temperature are the most influencing parameters for mechanical properties improvement. Genetic algorithm (GA has been applied to optimize the casting parameters that simultaneously maximize the responses.
A study on corrosion resistance of the Ti-10Mo experimental alloy after different processing methods

International Nuclear Information System (INIS)

Alves, A.P.R.; Santana, F.A.; Rosa, L.A.A.; Cursino, S.A.; Codaro, E.N.

2004-01-01

The purpose of this work was to evaluate the microstructure and corrosion resistance of the experimental Ti-10Mo (wt.%) alloy as-cast and treated. These alloys were divided into three groups for analysis: as-cast, after solution heat treatment at 1000 deg. C in argon atmosphere and remelting in centrifugal machine (investment casting). The microstructure formed from each condition was studied using optical microscopy. Corrosion behavior of titanium-molybdenum alloys in fluoridated physiological serum (0.15 M NaCl+0.03 M NaF [pH=6]) was studied and compared with Ti-6Al-4V alloy. In all electrodes systems, similar electrochemical response was obtained. In naturally aerated physiological serum, the corrosion rate is mainly controlled by dissolution process of a complex passive film. This film appears to be formed by titanium species with different oxidation states. Experimental Ti-10Mo alloy exhibit the lowest passive current densities, in particular, samples after heat treatment
Polymer−metal organic framework composite films as affinity layer for capacitive sensor devices

NARCIS (Netherlands)

Sachdeva, S.; Gravesteijn, Dirk J; Soccol, D.; Kapteijn, F.; Sudhölter, E.J.R.; Gascon, J.; Smet, de L.C.P.M.

2016-01-01

We report a simple method for sensor development using polymer-MOF composite films. Nanoparticles of NH2-MIL-53(Al) dispersed in a Matrimid polyimide were applied as a thin film on top of capacitive sensor devices with planar electrodes. These drop-cast films act as an affinity layer. Sensing
Polymer-metal organic framework composite films as affinity layer for capacitive sensor devices

NARCIS (Netherlands)

Sachdeva, Sumit; Soccol, Dimitri; Gravesteijn, Dirk J.; Kapteijn, Freek; Sudhölter, E.J.R.; Gascon, Jorge; Smet, de L.C.P.M.

2016-01-01

We report a simple method for sensor development using polymer-
MOF composite films. Nanoparticles of NH2-MIL-53(Al) dispersed in a Matrimid
polyimide were applied as a thin film on top of capacitive sensor devices with planar electrodes. These drop-cast films act as an affinity layer.
Design and characterization of chitosan/zeolite composite films — Effect of zeolite type and zeolite dose on the film properties

International Nuclear Information System (INIS)

Barbosa, Gustavo P.; Debone, Henrique S.; Severino, Patrícia; Souto, Eliana B.; Silva, Classius F. da

2016-01-01

Chitosan films can be used as wound dressings for the treatment of chronic wounds and severe burns. The antimicrobial properties of these films may be enhanced by the addition of silver. Despite the antimicrobial activity of silver, several studies have reported the cytotoxicity as a factor limiting its biomedical applications. This problem may, however, be circumvented by the provision of sustained release of silver. Silver zeolites can be used as drug delivery platforms to extend the release of silver. The objective of this study was to evaluate the addition of clinoptilolite and A-type zeolites in chitosan films. Sodium zeolites were initially subjected to ion-exchange in a batch reactor. Films were prepared by casting technique using a 2% w/w chitosan solution and two zeolite doses (0.1 or 0.2% w/w). Films were characterized by thermal analysis, color analysis, scanning electron microscopy, X-ray diffraction, and water vapor permeation. The results showed that films present potential for application as dressing. The water vapor permeability is one of the main properties in wound dressings, the best results were obtained for A-type zeolite/chitosan films, which presented a brief reduction of this property in relation to zeolite-free chitosan film. On the other hand, the films containing clinoptilolite showed lower water vapor permeation, which may be also explained by the best distribution of the particles into the polymer which also promoted greater thermal resistance. - Highlights: • Zeolite/chitosan composite films were prepared by casting technique. • Micrographs showed slight difference according to the content and A-type zeolite. • The barrier properties of the films were suitable to the dressing application. • Film characterization suggested that zeolites interacted with the chitosan chain.
Design and characterization of chitosan/zeolite composite films — Effect of zeolite type and zeolite dose on the film properties

Energy Technology Data Exchange (ETDEWEB)

Barbosa, Gustavo P.; Debone, Henrique S. [Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema (Brazil); Severino, Patrícia [Universidade Tiradentes, Instituto de Tecnologia e Pesquisa, Aracaju (Brazil); Souto, Eliana B. [Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Coimbra (FFUC), Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548, Coimbra (Portugal); Center for Neuroscience and Cell Biology & Institute for Biomedical Imaging and Life Sciences (CNC-IBILI), University of Coimbra, Pólo das Ciências da Saúde, Azinhaga de Santa Comba, 3000-548, Coimbra (Portugal); Silva, Classius F. da, E-mail: cfsilva@unifesp.br [Instituto de Ciências Ambientais, Químicas e Farmacêuticas, Universidade Federal de São Paulo, Diadema (Brazil)

2016-03-01

Chitosan films can be used as wound dressings for the treatment of chronic wounds and severe burns. The antimicrobial properties of these films may be enhanced by the addition of silver. Despite the antimicrobial activity of silver, several studies have reported the cytotoxicity as a factor limiting its biomedical applications. This problem may, however, be circumvented by the provision of sustained release of silver. Silver zeolites can be used as drug delivery platforms to extend the release of silver. The objective of this study was to evaluate the addition of clinoptilolite and A-type zeolites in chitosan films. Sodium zeolites were initially subjected to ion-exchange in a batch reactor. Films were prepared by casting technique using a 2% w/w chitosan solution and two zeolite doses (0.1 or 0.2% w/w). Films were characterized by thermal analysis, color analysis, scanning electron microscopy, X-ray diffraction, and water vapor permeation. The results showed that films present potential for application as dressing. The water vapor permeability is one of the main properties in wound dressings, the best results were obtained for A-type zeolite/chitosan films, which presented a brief reduction of this property in relation to zeolite-free chitosan film. On the other hand, the films containing clinoptilolite showed lower water vapor permeation, which may be also explained by the best distribution of the particles into the polymer which also promoted greater thermal resistance. - Highlights: • Zeolite/chitosan composite films were prepared by casting technique. • Micrographs showed slight difference according to the content and A-type zeolite. • The barrier properties of the films were suitable to the dressing application. • Film characterization suggested that zeolites interacted with the chitosan chain.
Effect of initial as-cast microstructure on semisolid microstructure of AZ91D alloy during the strain-induced melt activation process

International Nuclear Information System (INIS)

Wang, J.G.; Lin, H.Q.; Li, Y.Q.; Jiang, Q.C.

2008-01-01

The effects of different as-cast microstructures which were initially cast in graphite, metal, sand and firebrick moulds, respectively on the semisolid microstructure of AZ91D alloy, have been investigated during the strain-induced melt activation (SIMA) process. The experimental results showed that the moulds with high cooling capacity could produce the fine-grained as-cast microstructure in which the fine α-Mg dendrites were surrounded by a narrow layer of eutectic mixtures. After compressive deformation, in the fine-grained as-cast microstructure, the more systemic strain energy would be gradually accumulated and abundantly stored due to uniform inner crystal lattice distortion, so the recrystallization was easily induced by the stored strain energy at the elevated temperature. As a channel for the diffusion of atoms, the subgrain boundary along which Al element was enriched, foremost melted above the eutectic temperature and resulted in the separation of neighboring subgrains from primary dendrites. Therefore, the refining role of recrystallization on the microstructural evolution from dendrite to globular particles in morphology was easier to play in the fine-grained as-cast microstructure, which was advantageous for the production of fine-grained semisolid microstructure. Additionally, in the fine-grained as-cast microstructure, the melting fracture of narrow secondary dendritic arms was easy to occur in their roots, which also attributed to the production of fine globular grains in semisolid microstructure from primary dendrites. The finer dendrites in the initial as-cast alloy could evolve into the finer globular grains with relatively small grain size distribution range in the semisolid microstructure during partial remelting; therefore, the finer the dendrites in the initial as-cast microstructure, the better were the tensile properties of the evolved semisolid microstructure
Stochastic simulation of grain growth during continuous casting

International Nuclear Information System (INIS)

Ramirez, A.; Carrillo, F.; Gonzalez, J.L.; Lopez, S.

2006-01-01

The evolution of microstructure is a very important topic in material science engineering because the solidification conditions of steel billets during continuous casting process affect directly the properties of the final products. In this paper a mathematical model is described in order to simulate the dendritic growth using data of real casting operations; here a combination of deterministic and stochastic methods was used as a function of the solidification time of every node in order to create a reconstruction about the morphology of cast structures
Stochastic simulation of grain growth during continuous casting

Energy Technology Data Exchange (ETDEWEB)

Ramirez, A. [Department of Aerounatical Engineering, S.E.P.I., E.S.I.M.E., IPN, Instituto Politecnico Nacional (Unidad Profesional Ticoman), Av. Ticoman 600, Col. Ticoman, C.P.07340 (Mexico)]. E-mail: adalop123@mailbanamex.com; Carrillo, F. [Department of Processing Materials, CICATA-IPN Unidad Altamira Tamps (Mexico); Gonzalez, J.L. [Department of Metallurgy and Materials Engineering, E.S.I.Q.I.E.-IPN (Mexico); Lopez, S. [Department of Molecular Engineering of I.M.P., AP 14-805 (Mexico)

2006-04-15

The evolution of microstructure is a very important topic in material science engineering because the solidification conditions of steel billets during continuous casting process affect directly the properties of the final products. In this paper a mathematical model is described in order to simulate the dendritic growth using data of real casting operations; here a combination of deterministic and stochastic methods was used as a function of the solidification time of every node in order to create a reconstruction about the morphology of cast structures.
Liquid and vapour water transfer through whey protein/lipid emulsion films.

Science.gov (United States)

Kokoszka, Sabina; Debeaufort, Frederic; Lenart, Andrzej; Voilley, Andree

2010-08-15

Edible films and coatings based on protein/lipid combinations are among the new products being developed in order to reduce the use of plastic packaging polymers for food applications. This study was conducted to determine the effect of rapeseed oil on selected physicochemical properties of cast whey protein films. Films were cast from heated (80 degrees C for 30 min) aqueous solutions of whey protein isolate (WPI, 100 g kg(-1) of water) containing glycerol (50 g kg(-1) of WPI) as a plasticiser and different levels of added rapeseed oil (0, 1, 2, 3 and 4% w/w of WPI). Measurements of film microstructure, laser light-scattering granulometry, differential scanning calorimetry, wetting properties and water vapour permeability (WVP) were made. The emulsion structure in the film suspension changed significantly during drying, with oil creaming and coalescence occurring. Increasing oil concentration led to a 2.5-fold increase in surface hydrophobicity and decreases in WVP and denaturation temperature (T(max)). Film structure and surface properties explain the moisture absorption and film swelling as a function of moisture level and time and consequently the WVP behaviour. Small amounts of rapeseed oil favourably affect the WVP of WPI films, particularly at higher humidities. Copyright (c) 2010 Society of Chemical Industry.
Phased arrays techniques and split spectrum processing for inspection of thick titanium casting components

International Nuclear Information System (INIS)

Banchet, J.; Chahbaz, A.; Sicard, R.; Zellouf, D.E.

2003-01-01

In aircraft structures, titanium parts and engine members are critical structural components, and their inspection crucial. However, these structures are very difficult to inspect ultrasonically because of their large grain structure that increases noise drastically. In this work, phased array inspection setups were developed to detected small defects such as simulated inclusions and porosity contained in thick titanium casting blocks, which are frequently used in the aerospace industry. A Cut Spectrum Processing (CSP)-based algorithm was then implemented on the acquired data by employing a set of parallel bandpass filters with different center frequencies. This process led in substantial improvement of the signal to noise ratio and thus, of detectability
A Study on Sealing Process of Anodized Al Alloy Film

Science.gov (United States)

Tsujita, Takeshi; Sato, Hiroshi; Tsukahara, Sonoko; Ishikawa, Yuuichi

Since sealing is an important process to improve the corrosion resistance in practical application of anodized aluminum, we prepared anodic oxide films on A5052 alloy in an oxalic acid bath and a sulfuric acid bath, sealed them at various conditions, and analyzed them by scanning electron microscopy, acid-dissolution examination, admittance measurements and infrared spectroscopy. The pore radius of the oxalic acid anodized film was about 5 times larger than that of sulfuric acid anodized film, while the corrosion resistance of the former showed about 2 times higher value than the latter with the same sealed state and amount of hydroxide formed by sealing process of the former was 6 times larger than the latter, respectively. Steam sealing formed dense hydroxide and boiling water sealing formed big coral-like hydroxide, whereas the corrosion resistance of the film sealed by the former showed about 1.5 times higher value than that sealed by the latter, respectively. Thus microstructure of anodic oxide films and their surface morphology after sealing process clearly depended on their anodizing solution and the sealing condition and showed obvious relation to electric and corrosive properties.
Microstructure of As-cast Co-Cr-Mo Alloy Prepared by Investment Casting

Science.gov (United States)

Park, Jong Bum; Jung, Kyung-Hwan; Kim, Kang Min; Son, Yong; Lee, Jung-Il; Ryu, Jeong Ho

2018-04-01

The microstructure of a cobalt-base alloy (Co-Cr-Mo) obtained by an investment casting process was studied. This alloy complies with the ASTM F75 standard and is widely used in the manufacturing of orthopedic implants owing to its high strength, good corrosion resistance, and excellent biocompatibility. This work focuses on the resulting microstructures arising from normal industrial environmental conditions. The characterization of the samples was carried out using optical microscopy, field emission scanning electron microscopy and energy-dispersive spectroscopy. In this study, the as-cast microstructure is an γ-Co (face-centered cubic) dendritic matrix with the presence of a secondary phase, such as M23C6 carbides precipitated at grain boundaries and interdendritic zones. These precipitates are the main strengthening mechanism in this type of alloy. Other minority phases, such as the σ phase, were also detected, and their presence could be linked to the manufacturing process and environment.
Thin wall ductile iron casting as a substitute for aluminum alloy casting in automotive industry

Directory of Open Access Journals (Sweden)

M. Górny

2009-01-01

Full Text Available In paper it is presented thin wall ductile iron casting (TWDI as a substitute of aluminium alloy casting. Upper control arm made of ductile iron with wall thickness ranging from 2 – 3.7 mm was produced by inmold process. Structure, mechanical properties and computer simulations were investigated. Structural analysis of TWDI shows pearlitic-ferritic matrix free from chills and porosity. Mechanical testing disclose superior ultimate tensile strength (Rm, yield strength (Rp0,2 and slightly lower elongation (E of TWDI in comparison with forged control arm made of aluminium alloy (6061-T6. Moreover results of computer simulation of static loading for tested control arms are presented. Analysis show that the light-weight ductile iron casting can be loaded to similar working conditions as the forged Al alloy without any potential failures.
A Comparative Study on Wear Properties of As Cast, Cast Aged and Forge Aged A356 Alloy with Addition of Grain Refiner and/or Modifier

Directory of Open Access Journals (Sweden)

D.G. Mallapur

2015-03-01

Full Text Available In the present work, a comparative wear behavior study of three categories of materials viz, as cast, cast aged (casting followed by T6 and forge aged (forging followed by T6 has been investigated. Neither melt treatment nor solid state processing (like aging and forging seems to be altering the wear behavior of the materials drastically. Cast aged A356 materials exhibit higher wear resistance compared to as cast and forge aged A356 materials. Further, it was observed that cast aged samples register lower coefficient of friction compared to other samples. It is also noted that the difference in wear behavior is revealed only at conditions of higher load, higher speed and longer sliding distance of testing. At lower regimes the difference is marginal. Among cast aged samples, ones treated with combined addition exhibit better wear resistance compared to other materials. Samples treated with combined addition register lowest coefficient of friction followed by samples treated with Sr, those with B, those with Ti and untreated ones. Abrasive wear mechanism is found to be operative in the regime of higher loading and higher velocity of sliding. Adhesive wear mechanism seems to be dominating the wear process at the lower regime of load and velocity of sliding.
Processing and Characterization of Functionally Graded Aluminum (A319)—SiCp Metallic Composites by Centrifugal Casting Technique

Science.gov (United States)

Jayakumar, E.; Jacob, Jibin C.; Rajan, T. P. D.; Joseph, M. A.; Pai, B. C.

2016-08-01

Functionally graded materials (FGM) are successfully adopted for the design and fabrication of engineering components with location-specific properties. The present study describes the processing and characterization of A319 Aluminum functionally graded metal matrix composites (FGMMC) with 10 and 15 wt pct SiCp reinforcements. The liquid stir casting method is used for composite melt preparation followed by FGMMC formation by vertical centrifugal casting method. The process parameters used are the mold preheating temperature of 523 K (250 °C), melt pouring temperature of 1013 K (740 °C), and mold rotation speed of 1300 rpm. The study analyzes the distribution and concentration of reinforcement particles in the radial direction of the FGMMC disk along with the effects of gradation on density, hardness, mechanical strength, the variation in coefficient of thermal expansion and the wear resistance properties at different zones. Microstructures of FGMMC reveal an outward radial gradient distribution of reinforcements forming different zones. Namely, matrix-rich inner, transition, particles-rich outer, and chill zone of a few millimeters thick at the outer most periphery of the casting are formed. From 10-FGM, a radial shift in the position of SiCp maxima is observed in 15-FGM casting. The mechanical characterization depicts enhanced properties for the particle-rich zone. The hardness shows a graded nature in correlation with particle concentration and a maximum of 94.4 HRB has been obtained at the particle-rich region of 15-FGM. In the particle-rich zone, the lowest CTE value of 20.1 µm/mK is also observed with a compressive strength of 650 MPa and an ultimate tensile strength of 279 MPa. The wear resistance is higher at the particle-rich zone of the FGMMC.
Castability of Ti-6Al-7Nb alloy for dental casting

OpenAIRE

Wang, Tie Jun; 小林, 郁夫; 土居, 壽; 米山, 隆之

1999-01-01

Castability of Ti-6Al-7Nb alloy, CP Ti, and Co-Cr alloy was examined for mesh type and plate type specimens. The casting was carried out with a pressure type casting machine and commercial molding material. The castability of the mesh type specimen was evaluated in terms of the number of cast segments (castability index), and that of the plate type was evaluated by the area of the specimen (casting rate). X-ray images processed by a digital imaging technique were used to identify the casting...

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