Casting methods

DOEpatents

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

2012-12-18

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

The effect of surface oxide layer on the rate of hydrogen emission from aluminum and its alloys in a high vacuum

NASA Technical Reports Server (NTRS)

Makarova, V. I.; Zyabrev, A. A.

1979-01-01

The influence of surface oxide layers on the kinetics of hydrogen emission at the high vacuum of 10 to the minus 8th power torr was investigated at temperatures from 20 to 450 C using samples of pure AB00 aluminum and the cast alloy AMg. Cast and deformed samples of AMts alloy were used to study the effect of oxide film thickness on the rate of hydrogen emission. Thermodynamic calculations of the reactions of the generation and dissociation of aluminum oxide show that degasification at elevated temperatures (up to 600 C) and high vacuum will not reduce the thickness of artificially-generated surface oxide layers on aluminum and its alloys.

Synthesis, characterization and application of functional carbon nano materials

NASA Astrophysics Data System (ADS)

Chu, Jin

The synthesis, characterizations and applications of carbon nanomaterials, including carbon nanorods, carbon nanosheets, carbon nanohoneycombs and carbon nanotubes were demonstrated. Different growth techniques such as pulsed laser deposition, DC/RF sputtering, hot filament physical vapour deposition, evaporative casting and vacuum filtration methods were introduced or applied for synthesizing carbon nanomaterials. The morphology, chemical compositions, bond structures, electronic, mechanical and sensing properties of the obtained samples were investigated. Tilted well-aligned carbon micro- and nano- hybrid rods were fabricated on Si at different substrate temperatures and incident angles of carbon source beam using the hot filament physical vapour deposition technique. The morphologic surfaces and bond structures of the oblique carbon rod-like structures were investigated by scanning electron microscopy, field emission scanning electron microscopy, transmission electron diffraction and Raman scattering spectroscopy. The field emission behaviour of the fabricated samples was also tested. Carbon nanosheets and nanohoneycombs were also synthesized on Si substrates using a hot filament physical vapor deposition technique under methane ambient and vacuum, respectively. The four-point Au electrodes are then sputtered on the surface of the nanostructured carbon films to form prototypical humidity sensors. The sensing properties of prototypical sensors at different temperature, humidity, direct current, and alternative current voltage were characterized. Linear sensing response of sensors to relative humidity ranging from 11% to 95% is observed at room temperature. Experimental data indicate that the carbon nanosheets based sensors exhibit an excellent reversible behavior and long-term stability. It also has higher response than that of the humidity sensor with carbon nanohoneycombs materials. Conducting composite films containing carbon nanotubes (CNTs) were prepared in two different ways of evaporative casting and vacuum filtration methods using the biopolymer kappa-carrageenan (KC) as a dispersant. Evaporative casting and vacuum filtration film-formation processes were compared by testing electrical properties. Results showed that films produced using vacuum filtration had higher electrical properties than those prepared using the evaporative casting method. The evaporative casted multi walled carbon nanotubes composite films also performed as the best humidity sensor over all other films measured.

Embedding Optical Fibers In Cast Metal Parts

NASA Technical Reports Server (NTRS)

Gibler, William N.; Atkins, Robert A.; Lee, Chung E.; Taylor, Henry F.

1995-01-01

Use of metal strain reliefs eliminates breakage of fibers during casting process. Technique for embedding fused silica optical fibers in cast metal parts devised. Optical fiber embedded in flange, fitting, or wall of vacuum or pressure chamber, to provide hermetically sealed feedthrough for optical transmission of measurement or control signals. Another example, optical-fiber temperature sensor embedded in metal structural component to measure strain or temperature inside component.

Development and Implementation of the Casting of Rods Made of Refractory Cast Alloys

NASA Astrophysics Data System (ADS)

Kabanov, I. V.; Urin, S. L.; Ivanyuk, A. S.; Nesterov, A. N.; Bogdanov, S. V.

2017-12-01

The problems of the production of a so-called casting rod blank made of a refractory casting alloy in the vacuum induction furnaces of AO Metallurgical Plant Electrostal are considered. A unique technology of casting and subsequent treatment of as-cast rod blanks made of refractory alloys is developed, tested, and optimized. As a result of the developed and performed measures for the production of metal products in the Consarc furnace, the ingot-to-product yield increases by 15% as compared to metal casting in an ISV-1.0 furnace. As a result, we have widened the range of cast alloy grades and are going to cast metals for the manufacture of blanks of other sizes and ranges of alloy an steel grades.

Vacuum forming of thermoplastic sheet results in low-cost investment casting patterns

NASA Technical Reports Server (NTRS)

Clarke, A. E., Jr.

1964-01-01

Vacuum forming of a sheet of thermoplastic material around a mandrel conforming to the shape of the finished object provides a pattern for an investment mold. The thickness of the metal part is determined by the thickness of the plastic pattern.

CASTING FURNACES

DOEpatents

Ruppel, R.H.; Winters, C.E.

1961-01-01

A device is described for casting uranium which comprises a crucible, a rotatable table holding a plurality of molds, and a shell around both the crucible and the table. The bottom of the crucible has an eccentrically arranged pouring hole aligned with one of the molds at a time. The shell can be connected with a vacuum.

Casting technology for manufacturing metal rods from simulated metallic spent fuels

NASA Astrophysics Data System (ADS)

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

2000-09-01

A uranium metal rod 13.5 mm in diameter and 1,150 mm long was produced from simulated metallic spent fuels with advanced casting equipment using the directional-solidification method. A vacuum casting furnace equipped with a four-zone heater to prevent surface oxidation and the formation of surface shrinkage holes was designed. By controlling the axial temperature gradient of the casting furnace, deformation by the surface shrinkage phenomena was diminished, and a sound rod was manufactured. The cooling behavior of the molten uranium was analyzed using the computer software package MAGMAsoft.

Limitation of Shrinkage Porosity in Aluminum Rotor Die Casting

NASA Astrophysics Data System (ADS)

Kim, Young-Chan; Choi, Se-Weon; Kim, Cheol-Woo; Cho, Jae-Ik; Lee, Sung-Ho; Kang, Chang-Seog

Aluminum rotor prone to have many casting defects especially large amount of air and shrinkage porosity, which caused eccentricity, loss and noise during motor operation. Many attempts have been made to develop methods of shrinkage porosity control, but still there are some problems to solve. In this research, the process of vacuum squeeze die casting is proposed for limitation of defects. The 6 pin point gated dies which were in capable of local squeeze at the end ring were used. Influences of filling patterns on HPDC were evaluated and the important process control parameters were high injection speed, squeeze length, venting and process conditions. By using local squeeze and vacuum during filling and solidification, air and shrinkage porosity were significantly reduced and the feeding efficiency at the upper end ring was improved 10%. As a result of controlling the defects, the dynamometer test showed improved motor efficiency by more than 4%.

Fabrication of orderly nanostructured PLGA scaffolds using anodic aluminum oxide templates.

PubMed

Wang, Gou-Jen; Lin, Yan-Cheng; Li, Ching-Wen; Hsueh, Cheng-Chih; Hsu, Shan-Hui; Hung, Huey-Shan

2009-08-01

In this research, two simple fabrication methods to fabricate orderly nanostructured PLGA scaffolds using anodic aluminum oxide (AAO) template were conducted. In the vacuum air-extraction approach, the PLGA solution was cast on an AAO template first. The vacuum air-extraction process was then applied to suck the semi-congealed PLGA into the nanopores of the AAO template to form a bamboo sprouts array of PLGA. The surface roughness of the nanostructured scaffolds, ranging from 20 nm to 76 nm, can be controlled by the sucking time of the vacuum air-extraction process. In the replica molding approach, the PLGA solution was cast on the orderly scraggy barrier-layer surface of an AAO membrane to fabricate a PLGA scaffold of concave nanostructure. Cell culture experiments using the bovine endothelial cells (BEC) demonstrated that the nanostructured PLGA membrane can increase the cell growing rate, especially for the bamboo sprouts array scaffolds with smaller surface roughness.

Vertical discrepancy and microleakage of laser-sintered and vacuum-cast implant-supported structures luted with different cement types.

PubMed

Oyagüe, Raquel Castillo; Sánchez-Turrión, Andrés; López-Lozano, José Francisco; Suárez-García, M Jesús

2012-02-01

This study aimed to evaluate the vertical misfit and microleakage of laser-sintered and vacuum-cast cement-retained implant-supported frameworks. Three-unit implant-fixed structures were constructed with: (1) laser-sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC); and (3) vacuum-cast Pd-Au (CP). Every framework was luted onto 2 prefabricated abutments under constant seating pressure. Each alloy group was randomly divided into three subgroups (n=10) according to the cement used: (1) Ketac Cem Plus (KC); (2) Panavia F 2.0 (PF); and (3) RelyX Unicem 2 Automix (RXU). After 30 days of water ageing, vertical discrepancy was measured by SEM, and marginal microleakage was scored using a digital microscope. Three-way ANOVA and Student-Newman-Keuls tests were run to investigate the effect of alloy/fabrication technique, FDP retainer, and cement type on vertical misfit. Data for marginal microleakage were analysed with Kruskal-Wallis and Dunn's tests (α=0.05). Vertical discrepancy was affected by alloy/manufacturing technique and cement type (p<0.001). Despite the luting agent, LS structures showed the best marginal adaptation, followed by CP, and CC. Within each alloy group, KC provided the best fit, whilst the use of PF or RXU resulted in no significant differences. Regardless of the framework alloy, KC exhibited the highest microleakage scores, whilst PF and RXU showed values that were comparable to each other. Laser-sintered Co-Cr structures achieved the best fit in the study. Notwithstanding the framework alloy, resin-modified glass-ionomer demonstrated better marginal fit but greater microleakage than did MDP-based and self-adhesive dual-cure resin cements. All groups were within the clinically acceptable misfit range. Laser-sintered Co-Cr may be an alternative to cast base metal and noble alloys to obtain passive-fitting structures. Despite showing higher discrepancies, resin cements displayed lower microleakage than resin-modified glass-ionomer. Further research is necessary to determine whether low microleakage scores may guarantee a suitable seal that could compensate for misfit. Copyright © 2011 Elsevier Ltd. All rights reserved.

Fire-Retardant Decorative Inks For Aircraft Interiors

NASA Technical Reports Server (NTRS)

Kourtides, D. A.; Nir, Z.; Mikroyannidis, J. A.

1988-01-01

Report describes testing of commercial and experimental fire retardants for incorporation into acrylic printing inks used on aircraft-interior sandwich panels. Films of acrylic ink containing fire-retardant additives prepared by casting on glass plates. Solvent evaporated in vacuum, cast films cured at 80 to 100 degree C for 30 minutes in air-circulating oven. Thermochemical properties of films examined by thermogravimetric analysis and differential scanning calorimetry (DSC). Samples of inks cast on sheets of polyvinylfloride (PVF), and their limiting oxygen indices and smoke evolution measured.

How to Avoid Cast Saw Complications.

PubMed

Halanski, Matthew A

2016-06-01

As casts are routinely used in pediatric orthopaedics, casts saws are commonly used to remove such casts. Despite being a viewed as the "conservative" and therefore often assumed safest treatment modality, complications associated with the use of casts and cast saws occur. In this manuscript, we review the risk factors associated with cast saw injuries. Cast saw injuries are thermal or abrasive (or both) in nature. Thermal risk factors include: cast saw specifications (including a lack of attached vacuum), use of a dull blade, cutting in a concavity, too thin padding, and overly thick casting materials. Risk factors associated with abrasive injuries include: sharp blades, thin padding, and cutting over boney prominences. Because nearly all clinicians contact the skin with the blade during cast removal, appropriate "in-out technique" is critical. Such technique prevents a hot blade from remaining in contact with the skin for any significant time, diminishing the risk of burn. Similarly, using such technique prevents "dragging the blade" that may pull the skin taught, cutting it. It may be useful to teach proper technique as perforating a cast rather than cutting a cast.

Effect of flask vibration time on casting integrity, Surface Penetration and Coating Inclusion in lost foam casting of Al-Si Alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2011-01-17

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 ofmore » 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.« less

Vacuum investment cast PH13-8Mo corrosion resistant steel. (SAE standard)

DOE Office of Scientific and Technical Information (OSTI.GOV)

NONE

1991-07-01

An industry-wide interest has arisen with regards to the properties and capabilities of investment cast PH 13-8Mo corrosion resistant steel. Specifically of interest are the structural applications in the aerospace industry for this product heat treated to the H1000 condition. The objective of this AMEC cooperative test program was to generate and compile useful data for aerospace structural evaluation of investment cast PH 13-8Mo heat treated to H1000. The determination was made of overall mechanical properties, fatigue, fracture toughness, and crack growth data along with basic microstructural evaluation of the investment cast material. The evaluation of mechanical property variations betweenmore » cast and machined tensile specimens and evaluation of microstructural constituents. PH 13-8Mo, H1000 investment castings for use in the aerospace industry is included.« less

JPRS Report, Science and Technology, Europe.

DTIC Science & Technology

1991-02-15

VIDP furnace is a further development of the conventional vacuum induction melter (VIM). It has an independent smelting and processing unit, to...which various casting systems can be linked according to the modular principle. Unlike the conventional vacuum induction melter, the VIDP furnace does... induction coil and the crucible. The furnace body can be extracted for relining or replacement with another, ready-lined, fur- nace body. This

Fabrication of Ti-0.48Al Alloy by Centrifugal Casting.

PubMed

Park, Jong Bum; Lee, Jung-Il; Ryu, Jeong Ho

2018-09-01

Many of the unique properties of TiAl alloys that make are attractive for use in high-temperature structural applications also make it challenging to process them into useful products. Cast TiAl is rapidly nearing commercialization, particularly in the vehicle industry, owing to its low production cost. In this study, the centrifugal casting of a TiAl (Ti-48%Al, mole fraction) turbocharger was simulated and an experimental casting was created in vacuum using an induction melting furnace coupled to a ceramic composite mold. Numerical simulation results agreed with the experiment. The crystal structure, microstructure, and chemical composition of the TiAl prepared by centrifugal casting were studied by X-ray diffractometry, optical microscopy, field emission scanning electron microscopy (FE-SEM) and energy dispersive spectroscopy (EDS). FE-SEM and EDS examinations of the TiAl casting revealed that the thickness of the oxide layer (α-case) was typically less than 35 μm.

Evaluation of fit of cement-retained implant-supported 3-unit structures fabricated with direct metal laser sintering and vacuum casting techniques.

PubMed

Oyagüe, Raquel Castillo; Sánchez-Turrión, Andrés; López-Lozano, José Francisco; Montero, Javier; Albaladejo, Alberto; Suárez-García, María Jesús

2012-07-01

This study evaluated the vertical discrepancy of implant-fixed 3-unit structures. Frameworks were constructed with laser-sintered Co-Cr, and vacuum-cast Co-Cr, Ni-Cr-Ti, and Pd-Au. Samples of each alloy group were randomly luted in standard fashion using resin-modified glass-ionomer, self-adhesive, and acrylic/urethane-based cements (n = 12 each). Discrepancies were SEM analyzed. Three-way ANOVA and Student-Newman-Keuls tests were run (P < 0.05). Laser-sintered structures achieved the best fit per cement tested. Within each alloy group, resin-modified glass-ionomer and acrylic/urethane-based cements produced comparably lower discrepancies than the self-adhesive agent. The abutment position did not yield significant differences. All misfit values could be considered clinically acceptable.

Environmentally benign processing of YAG transparent wafers

NASA Astrophysics Data System (ADS)

Yang, Yan; Wu, Yiquan

2015-12-01

Transparent yttrium aluminum garnet (YAG) wafers were successfully produced via aqueous tape casting and vacuum sintering techniques using a new environmentally friendly binder, a copolymer of isobutylene and maleic anhydride with the commercial name ISOBAM (noted as ISOBAM). Aqueous YAG slurries were mixed by ball-milling, which was followed by de-gassing and tape casting of wafers. The final YAG green tapes were homogenous and flexible, and could be bent freely without cracking. After the drying and sintering processes, transparent YAG wafers were achieved. The microstructures of both the green tape and vacuum-sintered YAG ceramic were observed by scanning electronic microscopy (SEM). Phase compositions were examined by X-ray diffraction (XRD). Optical transmittance was measured in UV-VIS regions with the result that the transmittance is 82.6% at a wavelength of 800 nm.

Method For Removing Volatile Components From A Gel-Cast Ceramic Article

DOEpatents

Klug, Frederic Joseph; DeCarr, Sylvia Marie

2004-09-07

A method of removing substantially all of the volatile component in a green, volatile-containing ceramic article is disclosed. The method comprises freezing the ceramic article; and then subjecting the frozen article to a vacuum for a sufficient time to freeze-dry the article. Frequently, the article is heated while being freeze-dried. Use of this method efficiently reduces the propensity for any warpage of the article. The article is often formed from a ceramic slurry in a gel-casting process. A method for fabricating a ceramic core used in investment casting is also described.

Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties.

PubMed

Kuo, Chin-Guo; Chang, Ho; Wang, Jian-Hao

2016-03-24

In this investigation, anodic aluminum oxide (AAO) with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn) into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO) nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 μm, 60 μm, and 70 μm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA.

Investigation of Re-X glass ceramic for acceleration insulating columns

NASA Astrophysics Data System (ADS)

Faltens, A.; Rosenblum, S.

1985-05-01

In an induction linac the accelerating voltage appears along a voltage-graded vacuum insulator column which is a performance limiting and major cost component. Re-X glass ceramic insulators have the long-sought properties of allowing cast-in gradient electrodes, good breakdown characteristics, and compatibility with high vacuum systems. Re-X is a glass ceramic developed by General Electric for use in the manufacture of electrical apparatus, such as vacuum arc interrupters. We have examined vacuum outgassing behavior and voltage breakdown in vacuum and find excellent performance. The housings are in the shape of tubes with type 430 stainless steel terminations. Due to a matched coefficient of thermal expansion between metal and insulator, no vacuum leaks have resulted from any welding operation. The components should be relatively inexpensive to manufacture in large sizes and appear to be a very attractive accelerator column. We are planning to use a standard GE housing in our MBE-4 induction linac.

Valve seat pores sealed with thermosetting monomer

NASA Technical Reports Server (NTRS)

Olmore, A. B.

1966-01-01

Hard anodic coating provides a smooth wear resistant value seating surface on a cast aluminum alloy valve body. Vacuum impregnation with a thermosetting monomer, diallyl phthalate, seals the pores on the coating to prevent galvanic corrosion.

Fabrication of ZnO Nanowires Arrays by Anodization and High-Vacuum Die Casting Technique, and Their Piezoelectric Properties

PubMed Central

Kuo, Chin-Guo; Chang, Ho; Wang, Jian-Hao

2016-01-01

In this investigation, anodic aluminum oxide (AAO) with arrayed and regularly arranged nanopores is used as a template in the high-vacuum die casting of molten zinc metal (Zn) into the nanopores. The proposed technique yields arrayed Zn nanowires with an aspect ratio of over 600. After annealing, arrayed zinc oxide (ZnO) nanowires are obtained. Varying the anodizing time yields AAO templates with thicknesses of approximately 50 μm, 60 μm, and 70 μm that can be used in the fabrication of nanowires of three lengths with high aspect ratios. Experimental results reveal that a longer nanowire generates a greater measured piezoelectric current. The ZnO nanowires that are fabricated using an alumina template are anodized for 7 h and produce higher piezoelectric current of up to 69 pA. PMID:27023546

Inter-Batch Variation and the Effect of Casting Vacuum on Ballistic and Mechanical Properties of a High Performing Cast Composite Rocket Propellant

DTIC Science & Technology

2014-12-01

premature dewetting of crystal surfaces. This is a similar phenomenon to that described by Gocmez, et al. [7] for coarse/fine ratios of AP. That is...they postulated that a greater force is required to dewet fine AP crystals due to a larger surface area/volume ratio and therefore a larger overall...tensile strength. Dewetting of AP crystals from binder during the application of stress creates vacuoles which contribute to total specimen elongation

Discussion of "Investigation of Oxide Bifilms in Investment Cast Superalloy IN100 Parts I and II"*

NASA Astrophysics Data System (ADS)

Campbell, John

2017-10-01

Fuchs and Kaplan carried out experiments in an attempt to ascertain whether oxide bifilms were present in a vacuum-cast Ni-base superalloy but concluded negatively. Although this author challenged their interpretation of their findings, both parties had overlooked the presence in the alloy of boron which is now known to inhibit bifilm formation. However, even though boron can help significantly, improved filling system designs remain important if other damaging entrainment defects are to be avoided.

Does the casting mode influence microstructure, fracture and properties of different metal ceramic alloys?

PubMed

Bauer, José Roberto de Oliveira; Grande, Rosa Helena Miranda; Rodrigues-Filho, Leonardo Eloy; Pinto, Marcelo Mendes; Loguercio, Alessandro Dourado

2012-01-01

The aim of the present study was to evaluate the tensile strength, elongation, microhardness, microstructure and fracture pattern of various metal ceramic alloys cast under different casting conditions. Two Ni-Cr alloys, Co-Cr and Pd-Ag were used. The casting conditions were as follows: electromagnetic induction under argon atmosphere, vacuum, using blowtorch without atmosphere control. For each condition, 16 specimens, each measuring 25 mm long and 2.5 mm in diameter, were obtained. Ultimate tensile strength (UTS) and elongation (EL) tests were performed using a Kratos machine. Vickers Microhardness (VM), fracture mode and microstructure were analyzed by SEM. UTS, EL and VM data were statistically analyzed using ANOVA. For UTS, alloy composition had a direct influence on casting condition of alloys (Wiron 99 and Remanium CD), with higher values shown when cast with Flame/Air (p < 0.05). The factors 'alloy" and 'casting condition" influenced the EL and VM results, generally presenting opposite results, i.e., alloy with high elongation value had lower hardness (Wiron 99), and casting condition with the lowest EL values had the highest VM values (blowtorch). Both factors had significant influence on the properties evaluated, and prosthetic laboratories should select the appropriate casting method for each alloy composition to obtain the desired property.

TiC-Fe-Based Composite Coating Prepared by Self-Propagating High-Temperature Synthesis

NASA Astrophysics Data System (ADS)

He, Shen; Fan, Xi'an; Chang, Qingming; Xiao, Lixiang

2017-06-01

TiC-Fe-based composite coatings were prepared in situ by self-propagating high-temperature synthesis combined with vacuum expendable pattern casting process. The band-like TiC phase embedded in a continuous Fe binder. There were no obvious defects and impurities at the interface between coatings and matrices. Fe presented consecutively in the coating zones and substrate zones without interruption and the microhardness in the cross-sectional area of the coating-matrix reduces continuously from the coating to the matrix area, indicating a good metallurgical bonding between the coatings and matrices. The effect of casting temperature on the microstructure and hardness of TiC-Fe-based composite coating was investigated in detail. The TiC particles formed at low casting temperature were nearly spherical in shape, and the size of TiC particles increased with increasing casting temperature due to more agglomeration. The hardness of the coatings increased first and then decreased with increasing casting temperature, and reached the highest value of 68 HRC when the casting temperature was 1773 K (1500 °C), which was twice more than that of the matrix.

Casting evaluation of U-Zr alloy system fuel slug for SFR prepared by injection casting method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Song, Hoon; Kim, Jong-Hwan; Kim, Ki-Hwan

2013-07-01

Metal fuel slugs of U-Pu-Zr alloys for Sodium-cooled Fast Reactor (SFR) have conventionally been fabricated by a vacuum injection casting method. Recently, management of minor actinides (MA) became an important issue because direct disposal of the long-lived MA can be a long-term burden for a tentative repository up to several hundreds of thousand years. In order to recycle transuranic elements (TRU) retained in spent nuclear fuel, remote fabrication capability in a shielded hot cell should be prepared. Moreover, generation of long-lived radioactive wastes and loss of volatile species should be minimized during the recycled fuel fabrication step. In order tomore » prevent the evaporation of volatile elements such as Am, alternative fabrication methods of metal fuel slugs have been studied applying gravity casting, and improved injection casting in KAERI, including melting under inert atmosphere. And then, metal fuel slugs were examined with casting soundness, density, chemical analysis, particle size distribution and microstructural characteristics. Based on these results there is a high level of confidence that Am losses will also be effectively controlled by application of a modest amount of overpressure. A surrogate fuel slug was generally soundly cast by improved injection casting method, melted fuel material under inert atmosphere.« less

Plastic flow and microstructure of cast nickel aluminides at 1273 K

NASA Astrophysics Data System (ADS)

Schneibel, J. H.; Porter, W. D.; Horton, J. A.

1987-12-01

Chill-cast nickel aluminides based on Ni3Al were compression-tested in vacuum at 1273 K at strain rates ranging from 10-5 s-1 to 10-1 s-1. As the strain rate increases, the propensity for intergranular cracking increases. The ductile-to-brittle transition strain rate (DBTS) of as-cast Ni-22.5Al-0.5Hf-0.1B (at. pct) is approximately 10-1 s-1. Homogenization lowers this value by three orders of magnitude, to 10-4 s-1 (a homogenized specimen disintegrated completely at a rate of 10-3 s-1). The fine-grained structure of the as-cast alloy plays an important role in its relatively high DBTS. A hafnium-free alloy, Ni-24A1-0.1B, on the other hand, shows only a weak dependence of the DBTS on prior homogenization, and possible reasons for this finding are discussed.

Microstructure and corrosion behavior of die-cast AM60B magnesium alloys in a complex salt solution. A slow positron beam study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Y. F.; Yang, W.; Qin, Q. L.

2013-12-15

The microstructure and corrosion behavior of high pressure die-cast (HPDC) and super vacuum die-cast (SVDC) AM60B magnesium alloys were investigated in a complex salt solution using slow positron beam technique and potentiodynamic polarization tests. The experiments revealed that a CaCO 3 film was formed on the surface of the alloys and that the rate of CaCO 3 formation for the SVDC alloy with immersion time was slower than that of the HPDC alloy. The larger volume fraction of b-phase in the skin layer of the SVDC alloy than that of the HPDC alloy was responsible for the better corrosion resistance.

Measurement of the setting expansion of phosphate-bonded investment materials: Part I - Development of the Casting-Ring Test.

PubMed

Lloyd, C H; Yearn, J A; Cowper, G A; Blavier, J; Vanderdonckt, M

2004-07-01

The setting expansion is an important property for a phosphate-bonded investment material. This research was undertaken to investigate a test that might be suitable for its measurement when used in a Standard. In the 'Casting-Ring Test', the investment sample is contained in a steel ring and expands to displace a precisely positioned pin. Variables with the potential to alter routine reproduction of the value were investigated. The vacuum-mixer model is a production laboratory variable that must not be ignored and for this reason, experiments were repeated using a different vacuum-mixer located at a second test site. Restraint by the rigid ring material increased expansion, while force on the pin reduced it. Expansion was specific to the lining selected. Increased environmental temperature decreased the final value. Expansion was still taking place at a time at which its value might be measured. However, when these factors are set, the reproducibility of values for setting expansion was good at both test sites (coefficient of variation 14%, at most). The results revealed that with the control that is available reliable routine measurement is possible in a Standard test. The inter-laboratory variable, vacuum-mixer model, produced significant differences and it should be the subject of further investigation.

Manufacturing and High Heat Flux Testing of Brazed Flat-Type W/CuCrZr Plasma Facing Components

NASA Astrophysics Data System (ADS)

Lian, Youyun; Liu, Xiang; Feng, Fan; Chen, Lei; Cheng, Zhengkui; Wang, Jin; Chen, Jiming

2016-02-01

Water-cooled flat-type W/CuCrZr plasma facing components with an interlayer of oxygen-free copper (OFC) have been developed by using vacuum brazing route. The OFC layer for the accommodation of thermal stresses was cast onto the surface of W at a temperature range of 1150 °C-1200 °C in a vacuum furnace. The W/OFC cast tiles were vacuum brazed to a CuCrZr heat sink at 940 °C using the silver-free filler material CuMnSiCr. The microstructure, bonding strength, and high heat flux properties of the brazed W/CuCrZr joint samples were investigated. The W/Cu joint exhibits an average tensile strength of 134 MPa, which is about the same strength as pure annealed copper. High heat flux tests were performed in the electron beam facility EMS-60. Experimental results indicated that the brazed W/CuCrZr mock-up experienced screening tests of up to 15 MW/m2 and cyclic tests of 9 MW/m2 for 1000 cycles without visible damage. supported by National Natural Science Foundation of China (No. 11205049) and the National Magnetic Confinement Fusion Science Program of China (No. 2011GB110004)

Development of high purity large forgings for nuclear power plants

NASA Astrophysics Data System (ADS)

Tanaka, Yasuhiko; Sato, Ikuo

2011-10-01

The recent increase in the size of energy plants has been supported by the development of manufacturing technology for high purity large forgings for the key components of the plant. To assure the reliability and performance of the large forgings, refining technology to make high purity steels, casting technology for gigantic ingots, forging technology to homogenize the material and consolidate porosity are essential, together with the required heat treatment and machining technologies. To meet these needs, the double degassing method to reduce impurities, multi-pouring methods to cast the gigantic ingots, vacuum carbon deoxidization, the warm forging process and related technologies have been developed and further improved. Furthermore, melting facilities including vacuum induction melting and electro slag re-melting furnaces have been installed. By using these technologies and equipment, large forgings have been manufactured and shipped to customers. These technologies have also been applied to the manufacture of austenitic steel vessel components of the fast breeder reactors and components for fusion experiments.

The influence of cooling parameters on the speed of continuous steel casting

NASA Astrophysics Data System (ADS)

Tirian, G. O.; Gheorghiu, C. A.; Hepuţ, T.; Chioncel, C. P.

2018-01-01

This paper analyzes the cooling parameters of the continuous casting speed. In the researches carried out we aimed to establish some correlation equations between the parameters characterizing the continuous casting process, the temperature of the steel at the entrance to the crystallizer, the superheating of the steel and the flow of the cooling water in the crystallizer and different zones of the secondary cooling. Parallel to these parameters were also the values for the casting speed. The research was made for the casting of round ϕ270mm semi-finished steel products. The steel was developed in an electric EBT furnace with a capacity of 100t, treated in L.F. (Ladle - Furnace) and VD (Vacuum-Degassing) and poured in a 5-wire continuous casting plant. The obtained data was processed in MATLAB using three types of correlation equations. The obtained results are presented both in the analytical and graphical form, each correlation being analyzed from the technological point of view, indicating the optimal values for the independent parameters monitored. In the analysis we present a comparison between the results obtained after the three types of equations for each correlation.

Manufacturing Processes for Long-Life Gas Turbines

NASA Astrophysics Data System (ADS)

Hoppin, G. S.; Danesi, W. P.

1986-07-01

Dual-alloy turbine wheels produced by solid-state diffusion bonding of vacuum investment cast blade rings of one superalloy to preconsolidated powder metal hubs of a second superalloy have the long cyclic lives characteristic of wrought or powder superalloys combined with the high creep strength and net-shape blades characteristic of cast superalloys. A wide variety of superalloys and turbine configurations are compatible with this technology. Improved temperature capability turbine blades and vanes of the MAR-M 247 alloy made by directional solidification casting processes are now in volume production for Garrett gas turbines. Single-crystal alloys derivative to MAR-M 247 further extend the temperature capability of turbine blades and have been successfully engine tested. These blades are produced by a relatively simple modification of the processes used to manufacture directionally solidified blades.

Method for removing volatile components from a ceramic article, and related processes

DOEpatents

Klug, Frederic Joseph; DeCarr, Sylvia Marie

2002-01-01

A method of removing substantially all of the volatile component in a green, volatile-containing ceramic article is disclosed. The method comprises freezing the ceramic article; and then subjecting the frozen article to a vacuum for a sufficient time to freeze-dry the article. Frequently, the article is heated while being freeze-dried. Use of this method efficiently reduces the propensity for any warpage of the article. The article is often formed from a ceramic slurry in a gel-casting process. A method for fabricating a ceramic core used in investment casting is also described.

[The induction current, an ideal resource for the smelting of dental alloys].

PubMed

Ionescu, G; Chiper, C; Teofănescu, L; Brezulianu, C

1996-01-01

The authors present an electrical furnace for melting dental alloys, made by the German company BEGO. This furnace uses electrical current of high frequency. The advantages of this melting method are the possibility of controlling the adequate melting temperature for a specific type of alloy, the fusion in a protective environment of rare gas and casting by associating the centrifugation with the vacuum. This leads to exact castings without any defects. The authors describe as a personal contribution an external cooling system capable of maintaining the furnace's parameters even when the water pressure is low.

Optimization of Composition and Heat Treating of Die Steels for Extended Lifetime

DOE Office of Scientific and Technical Information (OSTI.GOV)

David Schwam; John F. Wallace; Quanyou Zhou

2002-01-30

An ''average'' die casting die costs fifty thousand dollars. A die used in making die cast aluminum engine blocks can cost well over one million dollars. These costs provide a strong incentive for extension of die life. While vacuum quenched Premium Grade H13 dies have become the most widely used in the United States, tool makers and die casters are constantly searching for new steels and heat treating procedures to extend die life. This project was undertaken to investigate the effects of composition and heat treating on die life and optimize these parameters.

Out-of-pile creep behavior of uranium carbide

NASA Technical Reports Server (NTRS)

Wright, T. R.; Seltzer, M. S.

1974-01-01

Compression creep tests were investigated on various UC-based fuel materials having a variation in both density and composition. Specimens were prepared by casting and by hot pressing. Steady-state creep rates were measured under vacuum at 1400 to 1800 C in the stress range 500-4000 psi.

The Effect of Boron and Zirconium on the Structure and Tensile Properties of the Cast Nickel-Based Superalloy ATI 718Plus

NASA Astrophysics Data System (ADS)

Hosseini, Seyed Ali; Abbasi, Seyed Mehdi; Madar, Karim Zangeneh

2018-04-01

The effects of boron and zirconium on cast structure, hardness, and tensile properties of the nickel-based superalloy 718Plus were investigated. For this purpose, five alloys with different contents of boron and zirconium were cast via vacuum induction melting and then purified via vacuum arc remelting. Microstructural analysis by light-optical microscope and scanning electron microscope equipped with energy-dispersive x-ray spectroscopy and phase studies by x-ray diffraction analysis were performed. The results showed that boron and zirconium tend to significantly reduce dendritic arm spacing and increase the amount of Laves, Laves/gamma eutectic, and carbide phases. It was also found that boron led to the formation of B4C and (Cr, Fe, Mo, Ni, Ti)3B2 phases and zirconium led to the formation of intermetallic phases and ZrC carbide. In the presence of boron and zirconium, the hardness and its difference between dendritic branches and inter-dendritic spaces increased by concentrating such phases as Laves in the inter-dendritic spaces. These elements had a negative effect on tensile properties of the alloy, including ductility and strength, mainly because of the increase in the Laves phase. It should be noted that the largest degradation of the tensile properties occurred in the alloys containing the maximum amount of zirconium.

Sixty Years of Casting Research

NASA Astrophysics Data System (ADS)

Campbell, John

2015-11-01

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

Triple Plate Mold Final Report: Optimization of the Mold Design and Casting Parameters for a Thin U-10mo Fuel Casting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aikin, Jr., Robert M.

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 numerousmore » 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 characterization are compared to the initial design.« less

Misfit and microleakage of implant-supported crown copings obtained by laser sintering and casting techniques, luted with glass-ionomer, resin cements and acrylic/urethane-based agents.

PubMed

Castillo-Oyagüe, Raquel; Lynch, Christopher D; Turrión, Andrés S; López-Lozano, José F; Torres-Lagares, Daniel; Suárez-García, María-Jesús

2013-01-01

This study evaluated the marginal misfit and microleakage of cement-retained implant-supported crown copings. Single crown structures were constructed with: (1) laser-sintered Co-Cr (LS); (2) vacuum-cast Co-Cr (CC) and (3) vacuum-cast Ni-Cr-Ti (CN). Samples of each alloy group were randomly luted in standard fashion onto machined titanium abutments using: (1) GC Fuji PLUS (FP); (2) Clearfil Esthetic Cement (CEC); (3) RelyX Unicem 2 Automix (RXU) and (4) DentoTemp (DT) (n=15 each). After 60 days of water ageing, vertical discrepancy was SEM-measured and cement microleakage was scored using a digital microscope. Misfit data were subjected to two-way ANOVA and Student-Newman-Keuls multiple comparisons tests. Kruskal-Wallis and Dunn's tests were run for microleakage analysis (α=0.05). Regardless of the cement type, LS samples exhibited the best fit, whilst CC and CN performed equally well. Despite the framework alloy and manufacturing technique, FP and DT provide comparably better fit and greater microleakage scores than did CEC and RXU, which showed no differences. DMLS of Co-Cr may be a reliable alternative to the casting of base metal alloys to obtain well-fitted implant-supported crowns, although all the groups tested were within the clinically acceptable range of vertical discrepancy. No strong correlations were found between misfit and microleakage. Notwithstanding the framework alloy, definitive resin-modified glass-ionomer (FP) and temporary acrylic/urethane-based (DT) cements demonstrated comparably better marginal fit and greater microleakage scores than did 10-methacryloxydecyl-dihydrogen phosphate-based (CEC) and self-adhesive (RXU) dual-cure resin agents. Copyright © 2012 Elsevier Ltd. All rights reserved.

The development of ultrahigh strength low alloy cast steels with increased toughness

NASA Astrophysics Data System (ADS)

Lynch, Paul C.

This work describes the initial work on the development of the next generation of ultrahigh strength low alloy (UHSLA) cast steels. These UHSLA cast steels have both ultrahigh strength levels and good impact toughness. The influence of heat treatment, secondary processing using hot isostatic processing (HIP), and chemical composition on the microstructure and properties of UHSLA cast steels have been evaluated. The extent of microsegregation reduction expected during the heat treatment of UHSLA cast steels has also been estimated by diffusion modeling. This new family of UHSLA cast steels is similar in composition and properties to UHSLA wrought steels. However, the heat treatment and secondary processing of the UHSLA cast steels is used to develop microstructures and properties typically developed through thermomechanical processing and heat treatment for wrought UHSLA steels. Two martensitic UHSLA steels, 4340+ (silicon modified 4340) and ES-1 were investigated for this study. For the 4340+ alloy, heat treatment variables evaluated include homogenization temperature and time, tempering temperature, and austempering temperature and time. For the ES-1 alloy, heat treatment variables evaluated include homogenization temperature and time, austenization temperature, cryogenic treatment, and tempering temperature. The effect of high temperature hot isostatic processing (HIP) on the 4340+ and ES- 1 alloys was also investigated. Tensile properties, charpy v-notch impact toughness (CVN), microstructures, and fractographs have all been characterized after heat treatment. The effects of HIP on microporosity reduction in the ES-1 alloy were also investigated. The experiments carried out on the investment cast 4340+ alloy have shown that increasing the homogenization temperature can increase CVN without changing the ultimate tensile strength (UTS) or yield strength (YS) of the cast material. By replacing the homogenization step in the conventional heat treatment process with a high temperature HIP treatment, both the CVN and ductility of the alloy was found to increase while maintaining comparable ultimate tensile strength (UTS) and yield strength (YS) levels as compared to the original homogenization treatment. Austempering the (IC) 4340+ material led to a significant increase in CVN and ductility at the expense of UTS and yield strength as the primarily martensitic microstructure was converted to a mixed martensitic-bainitic structure. An initial heat of induction melted, aluminum deoxidized investment cast ES-1 with 0.06 wt % of aluminum showed that the average -40°F and +72°F impact toughness, % elongation, and UTS and YS of the fully heat treated investment cast + HIP ES-1 material lagged significantly behind that of the vacuum degassed cast + HIP ES-1 ingot material. Even though the % elongation and impact toughness of the investment cast ES-1 material changed between heat treatment conditions, the average UTS and YS values remained relatively unchanged throughout the heat treatments for the investment cast study. Etched micrographs of the investment cast ES-1 material showed evidence of significant differences in microsegregation reduction between the samples homogenized at 2125°F for 4 hours and those not homogenized at 2125°F for 4 hours. SEM fracture surface work performed on the investment cast material clearly showed that the induction melted investment and aluminum killed cast material contained significant amounts of MnS and Al2O3 inclusions that were not discovered in the vacuum degassed cast ingot material. Lastly, the results of a third heat of induction melted, aluminum deoxidized investment cast ES-1 material possessing just 0.01wt% of aluminum showed that the decrease in aluminum content from the first experimental heat did not improve the mechanical properties of the investment cast material. (Abstract shortened by UMI.)

Development of Integrated Die Casting Process for Large Thin-Wall Magnesium Applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Carter, Jon T.; Wang, Gerry; Luo, Alan

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 improvemore » 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 improvement in tensile properties with vacuum casting. Plant trials with large castings revealed cavity fill issues attributed to cooling and partial solidification of metal in the shot sleeve while waiting for vacuum to be established in the die cavity. 6. Developed age-hardenable Mg-based alloys as potential alternatives to the AM60 and AZ91 alloys typically used in automotive applications. Mg-7%Al-based alloys having Sn or Sn+Si additions exhibited significant age hardening, but more work is needed to demonstrate significant improvement in tensile properties. Corrosion behavior of these alloys is between those of AM60 and AZ91 alloys. 7. Evaluated the die casting of magnesium directly onto either steel or aluminum tubes as a potential process to make large lightweight subassemblies. Samples were free of gross defects, but additional work is needed to increase the interfacial shear strength. Overall, the project demonstrated that an automotive door-in-white design incorporating a die cast magnesium inner panel and a stamped aluminum outer panel can achieve approximately 50% mass reduction compared to the stamped steel baseline door-in-white. This leads to reduced energy consumption when driving the vehicle, which should more than offset the increased embedded energy of manufacture associated with the lighter metals. However, additional design work would be needed in order to meet the mechanical performance required of a door. Development of high-strength, high-ductility magnesium alloy castings would help make this technology more attractive for potential use in the side doors on automobiles. Also, increased use of recycled magnesium and aluminum would reduce the embedded energy and greenhouse gas emissions associated with the manufacture of this type of lightweight door. Commercialization planning of the type of lightweight door technology addressed in this project would be contingent upon the doors meeting all technical performance requirements of the car maker. The specific lightweight door developed in this project didn’t meet some of those requirements, but a preliminary business case study was conducted anyhow. This study considered the ratio of cost increase to mass decrease when the lightweight door is compared to a baseline steel door. The ratio was found to be in an acceptable range for some vehicle programs, especially if the number of such vehicles to be produced is equal to or slightly less than the estimated 250,000-shot life of the die set. This would allow for the investment in the dies to be spread across many parts and thereby help minimize the cost increase.« less

8. VIEW OF FOUNDRY INDUCTION FURNACES, MODULE J. THE FOUNDRY ...

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

8. VIEW OF FOUNDRY INDUCTION FURNACES, MODULE J. THE FOUNDRY CASTING PROCESS WAS CONDUCTED IN A VACUUM. PLUTONIUM METAL WAS MELTED IN ONE OF FOUR ELECTRIC INDUCTION FURNACES TO FORM INGOTS. - Rocky Flats Plant, Plutonium Manufacturing Facility, North-central section of Plant, just south of Building 776/777, Golden, Jefferson County, CO

Influence of melting and casting methods and finish line design on the marginal discrepancy of nickel-chromium-titanium alloy crowns.

PubMed

Cogolludo, Pablo G; Suarez, María J; Peláez, Jesús; Lozano, José F L

2010-01-01

The aim of this study was to analyze the influence of melting and casting procedures and the cervical finish line design on the marginal fit of nickel-chromium-titanium alloy crowns. Sixty standardized specimens were prepared to receive metal-ceramic crowns and were divided into two groups according to the cervical finish line: chamfer or rounded shoulder. Three melting and casting procedures were analyzed: (1) induction-centrifuge (IC), (2) gas oxygen torch-centrifuge (TC), and (3) induction-vacuum/pressure (IP). The marginal fit was measured with an image analysis system. Significant differences (P =.005) were observed among the groups, with TC showing the lowest discrepancies (45.87 μm). No significant differences were observed between the two finish lines. The accuracy of fit achieved for the groups analyzed may be regarded as within the range of clinical acceptance.

Low-Cycle Fatigue Behavior of Die-Cast Mg Alloy AZ91

NASA Astrophysics Data System (ADS)

Rettberg, Luke; Anderson, Warwick; Jones, J. Wayne

An investigation has been conducted on the influence of microstructure and artificial aging response (T6) on the low-cycle fatigue behavior of super vacuum die-cast (SVDC) AZ91. Fatigue lifetimes were determined from total strain-controlled fatigue tests for strain amplitudes of 0.2%, 0.4% and 0.6%, under fully reversed loading at a frequency of 5 Hz. Cyclic stress-strain behavior was determined using incremental step test (IST) methods. Two locations in a prototype casting with different thicknesses and, therefore, solidification rates, microstructure and porosity, were examined. In general., at all total strain amplitudes fatigue life was unaffected by microstructure refinement and was attributed to significant levels of porosity. Cyclic softening and a subsequent increased cyclic hardening rate, compared to monotonic tests, were observed, independent of microstructure. These results, fractography and damage accumulation processes, determined from metallographic sectioning, are discussed.

Silicon Sheet Growth Development for the Large Area Sheet Task of the Low Cost Solar Array Project. Heat Exchanger Method - Ingot Casting Fixed Abrasive Method - Multi-Wire Slicing

NASA Technical Reports Server (NTRS)

Schmid, F.; Khattak, C. P.

1978-01-01

Solar cells fabricated from HEM cast silicon yielded up to 15% conversion efficiencies. This was achieved in spite of using unpurified graphite parts in the HEM furnace and without optimization of material or cell processing parameters. Molybdenum retainers prevented SiC formation and reduced carbon content by 50%. The oxygen content of vacuum cast HEM silicon is lower than typical Czochralski grown silicon. Impregnation of 45 micrometers diamonds into 7.5 micrometers copper sheath showed distortion of the copper layer. However, 12.5 micrometers and 15 micrometers copper sheath can be impregnated with 45 micrometers diamonds to a high concentration. Electroless nickel plating of wires impregnated only in the cutting edge showed nickel concentration around the diamonds. This has the possibility of reducing kerf. The high speed slicer fabricated can achieve higher speed and longer stroke with vibration isolation.

Autoclave Meltout of Cast Explosives

DTIC Science & Technology

1996-08-22

various tanks , kettles , and pelletizing equipment a usable product was recovered. This process creates large amounts of pink water requiring...vacuum treatment melt kettles , flaker belts, and improved material handling equipment in an integrated system. During the 1976/1977 period, AED...McAlester Army Ammo Plant , Oklahoma, to discuss proposed workload and inspect available facilities and equipment . Pilot model production and testing

Vacuum-assisted fluid flow in microchannels to pattern substrates and cells.

PubMed

Shrirao, Anil B; Kung, Frank H; Yip, Derek; Cho, Cheul H; Townes-Anderson, Ellen

2014-09-01

Substrate and cell patterning are widely used techniques in cell biology to study cell-to-cell and cell-substrate interactions. Conventional patterning techniques work well only with simple shapes, small areas and selected bio-materials. This paper describes a method to distribute cell suspensions as well as substrate solutions into complex, long, closed (dead-end) polydimethylsiloxane (PDMS) microchannels using negative pressure. Our method builds upon a previous vacuum-assisted method used for micromolding (Jeon et al 1999 Adv. Mater 11 946) and successfully patterned collagen-I, fibronectin and Sal-1 substrates on glass and polystyrene surfaces, filling microchannels with lengths up to 120 mm and covering areas up to 13 × 10 mm(2). Vacuum-patterned substrates were subsequently used to culture mammalian PC12 and fibroblast cells and amphibian neurons. Cells were also patterned directly by injecting cell suspensions into microchannels using vacuum. Fibroblast and neuronal cells patterned using vacuum showed normal growth and minimal cell death indicating no adverse effects of vacuum on cells. Our method fills reversibly sealed PDMS microchannels. This enables the user to remove the PDMS microchannel cast and access the patterned biomaterial or cells for further experimental purposes. Overall, this is a straightforward technique that has broad applicability for cell biology.

Vacuum-assisted Fluid Flow in Microchannels to Pattern Substrates and Cells

PubMed Central

Shrirao, Anil B.; Kung, Frank H.; Yip, Derek; Cho, Cheul H.; Townes-Anderson, Ellen

2014-01-01

Substrate and cell patterning are widely used techniques in cell biology to study cell-to-cell and cell-to-substrate interactions. Conventional patterning techniques work well only with simple shapes, small areas and selected bio-materials. This paper describes a method to distribute cell suspensions as well as substrate solutions into complex, long, closed (dead-end) polydimethylsiloxane (PDMS) microchannels using negative pressure. Our method builds upon a previous vacuum-assisted method used for micromolding (Jeon, Choi et al. 1999) and successfully patterned collagen-I, fibronectin and Sal-1 substrates on glass and polystyrene surfaces, filling microchannels with lengths up to 120 mm and covering areas up to 13 × 10 mm2. Vacuum-patterned substrates were subsequently used to culture mammalian PC12 and fibroblast cells and amphibian neurons. Cells were also patterned directly by injecting cell suspensions into microchannels using vacuum. Fibroblast and neuronal cells patterned using vacuum showed normal growth and minimal cell death indicating no adverse effects of vacuum on cells. Our method fills reversibly sealed PDMS microchannels. This enables the user to remove the PDMS microchannel cast and access the patterned biomaterial or cells for further experimental purposes. Overall, this is a straightforward technique that has broad applicability for cell biology. PMID:24989641

The manufacture of moulded supportive seating for the handicapped.

PubMed

Nelham, R L

1975-10-01

The wheelchair-bound population often have difficulty in obtaining a correct or comfortable posture in their chairs and sometimes develop pressure sores from long-duration sitting. This problem is being solved by manufacturing personalised, contoured seats which support the patient over the maximum area possible thereby reducing the pressure on the body and the incidence of pressure sores. A cast is obtained of the patient in a comfortable, medically correct posture and from this cast the seat is vacuum formed in thermoplastic materials or hand layed up in glass fibre reinforced resin. Some correction of deformity may be achieved. It is also possible to use the moulded seat in a vehicle.

Innovative Vacuum Distillation for Magnesium Recycling

NASA Astrophysics Data System (ADS)

Zhu, Tianbai; Li, Naiyi; Mei, Xiaoming; Yu, Alfred; Shang, Shixiang

Magnesium recycling now becomes a very important subject as magnesium consumption increases fast around the world. All commonly used magnesium die-casting alloys can be recycled and recovered to the primary metal quality. The recycled materials may be comprised of biscuits, sprues, runners, flash, overflows, dross, sludge, scrap parts, and old parts that are returned from service, An innovative magnesium recycle method, vacuum distillation, is developed and proved out to be able to recycle magnesium scraps, especially machining chips, oily magnesium, smelting sludge, dross or the mixture. With this process at a specific temperature and environment condition, magnesium in scraps can be gasified and then solidified to become crystal magnesium crown. This `recycled' magnesium crown is collected and used as the raw material of magnesium alloys. The experimental results show the vacuum distillation is a feasible and plausible method to recycle magnesium. Further, the cost analysis will be addressed in this paper.

Exploratory Thermal-mechanical Fatigue Results for Rene' 80 in Ultrahigh Vacuum

NASA Technical Reports Server (NTRS)

Sheinker, A. A.

1978-01-01

A limited study was conducted of the use of strainage partitioning for predicting the thermalmechanical fatigue life of cast nickel-base superalloy Rene' 80. The fatigue lives obtained by combined inphase thermal and mechanical strain cycling between 400 C (752 F) and 1000 C (1802 F) in an ultrahigh vacuum were considerably shorter than those represented by the four basic partitioned inelastic strainrange fatigue life relationships established previously for this alloy at 871 C (1600 F) and 1000 C (1832 F) in an ultrahigh vacuum. This behavior was attributed to the drastic decrease in ductility with decreasing temperature for this alloy. These results indicated that the prediction of the thermal-mechanical fatigue life of Rene' 80 by the method of strainrange partioning may be improved if based on the four basic fatigue life relationships determined at a lower temperature in the thermal-mechanical strain cycle.

Method of casting patterned dielectric structures

DOEpatents

Poco, John F.; Hrubesh, Lawrence W.

2001-01-01

A pattern of dielectric structures are formed directly on a substrate in a single step using sol-gel chemistry and molding procedures. The resulting dielectric structures are useful in vacuum applications for electronic devices. Porous, lightweight structures having a high aspect ratio that are suitable for use as spacers between the faceplate and baseplate of a field emission display can be manufactured using this method.

3. Credit BG. The interior of the control room appears ...

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

3. Credit BG. The interior of the control room appears in this view, looking north (0°). The control console in the room center permitted remote control of various propellant grinders and mixers in surrounding buildings. Television monitors (absent from their mounts in this view) permitted direct viewing of operating machinery. From foreground to background: Panel (1) contains OGAR warning light switches for Curing Buildings E-39, E-40, E-41 and E-86; (O=off, G=green safe, A=amber caution, R=red danger) Panel (2) E-85 Oxidizer Dryer Building console: OGAR switch Panel (3) E-84 Oxidizer Grinder Building console: controls for vibrator, feed, and hammer; Panel (4) E-36 Oxidizer Grinder Building console: controls for vibrator, feed, hammer, attritor, and SWECO ("SWECO" undefined) Panels (5) & (6) blank Panel (7) E-38 Mixer & Casting Building console: vacuum pump, blender, heating and cooling controls Panel (8) E-37 Mixer & Casting Building console: motor controls for 1 pint, 1 gallon, 5 gallon and 30 gallon mixers; vacuum pump, deluge (fire suppression), pot up/down, vibrator, feed, and SWECO. - Jet Propulsion Laboratory Edwards Facility, Weigh & Control Building, Edwards Air Force Base, Boron, Kern County, CA

Glass transition in thin supported polystyrene films probed by temperature-modulated ellipsometry in vacuum.

PubMed

Efremov, Mikhail Yu; Kiyanova, Anna V; Last, Julie; Soofi, Shauheen S; Thode, Christopher; Nealey, Paul F

2012-08-01

Glass transition in thin (1-200 nm thick) spin-cast polystyrene films on silicon surfaces is probed by ellipsometry in a controlled vacuum environment. A temperature-modulated modification of the method is used alongside a traditional linear temperature scan. A clear glass transition is detected in films with thicknesses as low as 1-2 nm. The glass transition temperature (T(g)) shows no substantial dependence on thickness for coatings greater than 20 nm. Thinner films demonstrate moderate T(g) depression achieving 18 K for thicknesses 4-7 nm. Less than 4 nm thick samples are excluded from the T(g) comparison due to significant thickness nonuniformity (surface roughness). The transition in 10-20 nm thick films demonstrates excessive broadening. For some samples, the broadened transition is clearly resolved into two separate transitions. The thickness dependence of the glass transition can be well described by a simple 2-layer model. It is also shown that T(g) depression in 5 nm thick films is not sensitive to a wide range of experimental factors including molecular weight characteristics of the polymer, specifications of solvent used for spin casting, substrate composition, and pretreatment of the substrate surface.

Beryllium Manufacturing Processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Goldberg, A

2006-06-30

This report is one of a number of reports that will be combined into a handbook on beryllium. Each report covers a specific topic. To-date, the following reports have been published: (1) Consolidation and Grades of Beryllium; (2) Mechanical Properties of Beryllium and the Factors Affecting these Properties; (3) Corrosion and Corrosion Protection of Beryllium; (4) Joining of Beryllium; (5) Atomic, Crystal, Elastic, Thermal, Nuclear, and other Properties of Beryllium; and (6) Beryllium Coating (Deposition) Processes and the Influence of Processing Parameters on Properties and Microstructure. The conventional method of using ingot-cast material is unsuitable for manufacturing a beryllium product.more » Beryllium is a highly reactive metal with a high melting point, making it susceptible to react with mold-wall materials forming beryllium compounds (BeO, etc.) that become entrapped in the solidified metal. In addition, the grain size is excessively large, being 50 to 100 {micro}m in diameter, while grain sizes of 15 {micro}m or less are required to meet acceptable strength and ductility requirements. Attempts at refining the as-cast-grain size have been unsuccessful. Because of the large grain size and limited slip systems, the casting will invariably crack during a hot-working step, which is an important step in the microstructural-refining process. The high reactivity of beryllium together with its high viscosity (even with substantial superheat) also makes it an unsuitable candidate for precision casting. In order to overcome these problems, alternative methods have been developed for the manufacturing of beryllium. The vast majority of these methods involve the use of beryllium powders. The powders are consolidated under pressure in vacuum at an elevated temperature to produce vacuum hot-pressed (VHP) blocks and vacuum hot-isostatic-pressed (HIP) forms and billets. The blocks (typically cylindrical), which are produced over a wide range of sizes (up to 183 cm dia. by 61 cm high), may be cut or machined into parts or be thermomechanically processed to develop the desired microstructure, properties, and shapes. Vacuum hot-isostatic pressing and cold-isostatic pressing (CIP) followed by sintering and possibly by a final HIP'ing (CIP/Sinter/HIP) are important in their use for the production of near net-shaped parts. For the same starting powder, a HIP'ed product will have less anisotropy than that obtained for a VHP'ed product. A schematic presentation illustrating the difference between VHP'ing and HIP'ing is shown in Figure I-1. The types of powders and the various beryllium grades produced from the consolidated powders and their ambient-temperature mechanical properties were presented in the consolidation report referred to above. Elevated-temperature properties and the effect of processing variables on mechanical properties are described in the mechanical properties report. Beryllium can also be deposited as coatings as well as freestanding forms. The microstructure, properties, and various methods used that are related to the deposition of beryllium are discussed in the report on beryllium coatings.« less

[A surface reacted layer study of titanium-zirconium alloy after dental casting].

PubMed

Zhang, Y; Guo, T; Li, Z; Li, C

2000-10-01

To investigate the influence of the mold temperature on the surface reacted layer of Ti-Zr alloy castings. Ti-Zr alloy was casted into a mold which was made of a zircon (ZrO2.SiO2) for inner coating and a phosphate-bonded material for outer investing with a casting machine (China) designed as vacuum, pressure and centrifuge. At three mold temperatures (room temperature, 300 degrees C, 600 degrees C) the Ti-Zr alloy was casted separately. The surface roughness of the castings was calculated by instrument of smooth finish (China). From the surface to the inner part the Knoop hardness and thickness in reacted layer of Ti-Zr alloy casting was measured. The structure of the surface reacted layer was analysed by SEM. Elemental analyses of the interfacial zone of the casting was made by element line scanning observation. The surface roughness of the castings was increased significantly with the mold temperature increasing. At a higher mold temperature the Knoop hardness of the reactive layer was increased. At the three mold temperature the outmost surface was very hard, and microhardness data decreased rapidly where they reached constant values. The thickness was about 85 microns for castings at room temperature and 300 degrees C, 105 microns for castings at 600 degrees C. From the SEM micrograph of the Ti-Zr alloy casting, the surface reacted layer could be divided into three different layers. The first layer was called non-structure layer, which thickness was about 10 microns for room temperature group, 20 microns for 300 degrees C and 25 microns for 600 degrees C. The second layer was characterized by coarse-grained acicular crystal, which thickness was about 50 microns for three mold temperatures. The third layer was Ti-Zr alloy. The element line scanning showed non-structure layer with higher level of element of O, Al, Si and Zr, The higher the mold temperature during casting, the deeper the Si permeating and in the second layer the element Si could also be found. The mold temperature is one of the major factors influencing to casting quality. In order to reduce the surface reacted layer of Ti-Zr alloy castings, the lower mold temperature and the investment without Si should be chosen.

108. DETAIL OF DENVER DISC FILTER IN CO91107, SUCTION END. ...

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

108. DETAIL OF DENVER DISC FILTER IN CO-91-107, SUCTION END. NOTE BEARING HOUSING WITH CAST LOGO, SUCTION PIPE GOING OFF TO THE RIGHT, AND FILTER DISC IN BACKGROUND. VACUUM INSIDE DISCS FURTHER DEWATERED CONCENTRATE. AS DISC SLOWLY ROTATED A BAR SCRAPED DRIED CONCENTRATE FROM OUTSIDE OF FILTER CLOTH. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

Silicon Ingot Casting - Heat Exchanger Method Multi-wire Slicing - Fixed Abrasive Slicing Technique. Phase 3 Silicon Sheet Growth Development for the Large Area Sheet Task of the Low-cost Solar Array Project

NASA Technical Reports Server (NTRS)

Schmid, F.; Khattak, C. P.

1979-01-01

Several 20 cm diameter silicon ingots, up to 6.3 kg. were cast with good crystallinity. The graphite heat zone can be purified by heating it to high temperatures in vacuum. This is important in reducing costs and purification of large parts. Electroplated wires with 45 um synthetic diamonds and 30 um natural diamonds showed good cutting efficiency and lifetime. During slicing of a 10 cm x 10 cm workpiece, jerky motion occurred in the feed and rocking mechanisms. This problem is corrected and modifications were made to reduce the weight of the bladeheat by 50%.

Surface modification of investment cast-316L implants: microstructure effects.

PubMed

El-Hadad, Shimaa; Khalifa, Waleed; Nofal, Adel

2015-03-01

Artificial femur stem of 316L stainless steel was fabricated by investment casting using vacuum induction melting. Different surface treatments: mechanical polishing, thermal oxidation and immersion in alkaline solution were applied. Thicker hydroxyapatite (HAP) layer was formed in the furnace-oxidized samples as compared to the mechanically polished ones. The alkaline treatment enhanced the precipitation of HAP on the samples. It was also observed that the HAP precipitation responded differently to the different phases of the microstructure. The austenite phase was observed to have more homogeneous and smoother layer of HAP. In addition, the growth of HAP was sometimes favored on the austenite phase rather than on ferrite phase. Copyright © 2014 Elsevier B.V. All rights reserved.

Evaluating the Use of Synthetic Replicas for SEM Identification of Bloodstains (with Emphasis on Archaeological and Ethnographic Artifacts).

PubMed

Hortolà, Policarp

2015-12-01

Some archaeological or ethnographic specimens are unavailable for direct examination using a scanning electron microscope (SEM) due to methodological obstacles or legal issues. In order to assess the feasibility of using SEM synthetic replicas for the identification of bloodstains (BSs) via morphology of red blood cells (RBCs), three fragments of different natural raw material (inorganic, stone; plant, wood; animal, shell) were smeared with peripheral human blood. Afterwards, molds and casts of the bloodstained areas were made using vinyl polysiloxane (VPS) silicone impression and polyurethane (PU) resin casting material, respectively. Then, the original samples and the resulting casts were coated with gold and examined in secondary-electron mode using a high-vacuum SEM. Results suggest that PU resin casts obtained from VPS silicone molds can preserve RBC morphology in BSs, and consequently that synthetic replicas are feasible for SEM identification of BSs on cultural heritage specimens made of natural raw materials. Although the focus of this study was on BSs, the method reported in this paper may be applicable to organic residues other than blood, as well as to the surface of other specimens when, for any reason, the original is unavailable for an SEM.

Effect of casting atmosphere on the marginal deficiency and misfit of Ni-Cr alloys with and without beryllium.

PubMed

da Silva, Leandro J; Leal, Monica B; Valente, Mariana L C; de Castro, Denise T; Pagnano, Valéria O; Dos Reis, Andréa C; Bezzon, Osvaldo L

2017-07-01

The marginal adaptation of prosthetic crowns is still a significant clinical problem. The purpose of this in vitro study was to evaluate the marginal deficiency and misfit of Ni-Cr alloys with and without beryllium under different casting conditions. Four casting conditions were selected: flame-torch, induction/argon, induction/vacuum, and induction/air; and 2 alloys were used, Ni-Cr-Be and Ni-Cr. For each group, 10 metal specimens were prepared. Silicone indirect impressions and analysis of the degree of rounding were used to evaluate the marginal deficiencies of metal copings, and a standardized device for the setting pressure associated with optical microscopy was used to analyze the marginal misfit. Results were evaluated with 2-way ANOVA (α=.05), followed by the Tukey honest significant difference post hoc test, and the Pearson correlation test (α=.05). Alloy (P<.001) and casting technique (P<.001) were shown to affect marginal deficiencies. The Ni-Cr cast using the torch technique showed the highest marginal deficiency, and the Ni-Cr-Be cast in a controlled argon atmosphere showed the lowest (P<.001). Alloy (P=.472) and casting techniques (P=.206) did not affect the marginal misfit, but significant differences were found in the interaction (P=.001); the lowest misfit was achieved using the Ni-Cr-Be, and the highest misfit occurred with the molten Ni-Cr, using the cast torch technique. No correlation was found between deficiency and marginal misfit (r=.04, P=.69). The interactions demonstrated that the alloy containing beryllium that was cast in an argon atmosphere led to reduced marginal deficiency. Improved marginal adaptation can be achieved for the same alloy by using the torch technique. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

A Short Study of Large Rotary Forged Cylinders

DTIC Science & Technology

1979-06-01

ESR Steel Hollow ESR Steel Rotary Forge Vacuum Degassed Steel 20. ABSTRACT (Continue on reverse aide It necessary and identity by block number...treatment rging Line was used to produce steel for the Advanced ocram. Cylinders were rotary forged from cast hollow ESR ssed steel . Anomalies in the data...prompted a more detailed The results are presented. Satisfactory properties were cuum degassed steel . However, the very light forging th the very

Vacuum Plasma Spray Forming of Copper Alloy Liners for Regeneratively Cooled Liquid Rocket Combustion Chambers

NASA Technical Reports Server (NTRS)

Zimmerman, Frank

2003-01-01

Vacuum plasma spray (VPS) has been demonstrated as a method to form combustion chambers from copper alloys NARloy-Z and GRCop-84. Vacuum plasma spray forming is of particular interest in the forming of CuCrNb alloys such as GRCop-84, developed by NASA s Glenn Research Center, because the alloy cannot be formed using conventional casting and forging methods. This limitation is related to the levels of chromium and niobium in the alloy, which exceed the solubility limit in copper. Until recently, the only forming process that maintained the required microstructure of CrNb intermetallics was powder metallurgy formation of a billet from powder stock, followed by extrusion. This severely limits its usefulness in structural applications, particularly the complex shapes required for combustion chamber liners. This paper discusses the techniques used to form combustion chambers from CuCrNb and NARloy-Z, which will be used in regeneratively cooled liquid rocket combustion chambers.

A combined arc-melting and tilt-casting furnace for the manufacture of high-purity bulk metallic glass materials.

PubMed

Soinila, E; Pihlajamäki, T; Bossuyt, S; Hänninen, H

2011-07-01

An arc-melting furnace which includes a tilt-casting facility was designed and built, for the purpose of producing bulk metallic glass specimens. Tilt-casting was chosen because reportedly, in combination with high-purity processing, it produces the best fatigue endurance in Zr-based bulk metallic glasses. Incorporating the alloying and casting facilities in a single piece of equipment reduces the amount of laboratory space and capital investment needed. Eliminating the sample transfer step from the production process also saves time and reduces sample contamination. This is important because the glass forming ability in many alloy systems, such as Zr-based glass-forming alloys, deteriorates rapidly with increasing oxygen content of the specimen. The challenge was to create a versatile instrument, in which high purity conditions can be maintained throughout the process, even when melting alloys with high affinity for oxygen. Therefore, the design provides a high-vacuum chamber to be filled with a low-oxygen inert atmosphere, and takes special care to keep the system hermetically sealed throughout the process. In particular, movements of the arc-melting electrode and sample manipulator arm are accommodated by deformable metal bellows, rather than sliding O-ring seals, and the whole furnace is tilted for tilt-casting. This performance of the furnace is demonstrated by alloying and casting Zr(55)Cu(30)Al(10)Ni(5) directly into rods up to ø 10 mm which are verified to be amorphous by x-ray diffraction and differential scanning calorimetry, and to exhibit locally ductile fracture at liquid nitrogen temperature.

Research regarding the vacuuming of liquid steel on steel degassing

NASA Astrophysics Data System (ADS)

Magaon, M.; Radu, M.; Şerban, S.; Zgripcea, L.

2018-01-01

When the liquid steel comes in contact with the atmosphere of the elaboration aggregates, a process of gas diffusion into the metal bath takes place on the one hand, and on the other hand a process that allows them to pass from the metal bath into the atmosphere. The meaning of these processes is determined by a number of factors as follows: the quality of raw and auxiliary materials (moisture content, oils, etc.), the boiling intensity, the evacuation duration, the properties of used slags, the values of the casting ladle processing parameters (bubbling, vacuuming, etc.). The research was carried out at an electrical steelwork, equipped with an electric arc furnace type EBT (Electric Bottom Tapping) capacity 100t, LF (Ladle-Furnace) and VD (Vacuum Degassing) facilities, establishing some correlations between the vacuuming parameters from the V.D.facility and the amounts of hydrogen and nitrogen removed from the metal bath, as well as their removal efficiency, were taken into consideration. The obtained data was processed in MATLAB calculation program, the established correlations form was presented both in analytical and graphical form. The validity of these correlations was verified in practice, being particularly useful in research.

Effect of electric arc, gas oxygen torch and induction melting techniques on the marginal accuracy of cast base-metal and noble metal-ceramic crowns.

PubMed

Gómez-Cogolludo, Pablo; Castillo-Oyagüe, Raquel; Lynch, Christopher D; Suárez-García, María-Jesús

2013-09-01

The aim of this study was to identify the most appropriate alloy composition and melting technique by evaluating the marginal accuracy of cast metal-ceramic crowns. Seventy standardised stainless-steel abutments were prepared to receive metal-ceramic crowns and were randomly divided into four alloy groups: Group 1: palladium-gold (Pd-Au), Group 2: nickel-chromium-titanium (Ni-Cr-Ti), Group 3: nickel-chromium (Ni-Cr) and Group 4: titanium (Ti). Groups 1, 2 and 3 were in turn subdivided to be melted and cast using: (a) gas oxygen torch and centrifugal casting machine (TC) or (b) induction and centrifugal casting machine (IC). Group 4 was melted and cast using electric arc and vacuum/pressure machine (EV). All of the metal-ceramic crowns were luted with glass-ionomer cement. The marginal fit was measured under an optical microscope before and after cementation using image analysis software. All data was subjected to two-way analysis of variance (ANOVA). Duncan's multiple range test was run for post-hoc comparisons. The Student's t-test was used to investigate the influence of cementation (α=0.05). Uncemented Pd-Au/TC samples achieved the best marginal adaptation, while the worst fit corresponded to the luted Ti/EV crowns. Pd-Au/TC, Ni-Cr and Ti restorations demonstrated significantly increased misfit after cementation. The Ni-Cr-Ti alloy was the most predictable in terms of differences in misfit when either torch or induction was applied before or after cementation. Cemented titanium crowns exceeded the clinically acceptable limit of 120μm. The combination of alloy composition, melting technique, casting method and luting process influences the vertical seal of cast metal-ceramic crowns. An accurate use of the gas oxygen torch may overcome the results attained with the induction system concerning the marginal adaptation of fixed dental prostheses. Copyright © 2013 Elsevier Ltd. All rights reserved.

[The design of Co-Cr-Mo alloy combining the framework with porcelain fused to metal restorations and determination of the mechanical properties].

PubMed

Chao, Yong-lie; Lui, Chang-hong; Li, Ning; Yang, Xiao-yu

2005-02-01

To investigate a kind of Co-Cr-Mo alloys used for both porcelain fused to metal (PFM) restorations and casting framework of removable partial dentures. The Co-Cr-Mo alloy underwent the design for elementary compositions of the alloys and the production from the raw materials by means of a vacuum melt furnace. The strength, hardness, plasticity and casting ability of the alloy were examined with metal tensile test. Vickers hardness test and grid casting were examined respectively. The microstructure of the Co-Cr-Mo alloy was also inspected by scanning electron microscope and X-ray diffraction analysis. The elementary composition of DA9-4 alloy mainly consisted of Co 54%-67%, Cr 21%-26%, Mo 5%-8%, W 5%-8%, Si 1%-3%, Mn 0.1%-0.25% and trace elements. The yield strength of the alloy was 584 MPa, while the tensile strength was 736 MPa. The coefficient of expansion was 15.0%, the Vickers hardness reached 322, and the casting ratio exibited 100%. The DA9-4 Co-Cr-Mo alloy used for PFM and framework shown in this paper can meet the clinical demands and have reached the objects of the experiment plan.

Fabrication and life testing of thermionic converters

NASA Technical Reports Server (NTRS)

Yang, L.; Bruce, R.

1973-01-01

An unfueled converter containing a chloride-fluoride duplex tungsten emitter of 4.78 eV vacuum work function was tested for 46,647 hours at an emitter temperature of 1973 K and an electrode power output of about 8 watts/sq cm. The test demonstrated the superior and stable performance of the (110) oriented tungsten emitter at high temperatures. Three 90 UC-10 ZrC(C/U = 1.04, tungsten additive = 4 wt %) fueled converters were fabricated and tested at an emitter temperature of 1873 K. Converter containing chloride-arc-cast duplex tungsten cladding showed temperature thermionic performance and slower rate of performance drop than converter containing chloride-fluoride duplex tungsten cladding. This is believed to be due to the superior fuel component diffusion resistance of the arc-cast tungsten substrate used in the fuel cladding. It was shown that a converter containing a carbide fueled chloride-arc-cast duplex tungsten emitter with an initial electrode power output of 6.80 watts/sq cm could still deliver an electrode power output of 6.16 watts/sq cm after 18,632 hours of operation at an emitter temperature of 1873 K.

Tensile Properties of Molybdenum and Tungsten from 2500 to 3700 F

NASA Technical Reports Server (NTRS)

Hall, Robert W.; Sikora, Paul F.

1959-01-01

Specimens of commercially pure sintered tungsten, arc-cast unalloyed molybdenum, and two arc-cast molybdenum-base alloys (one with 0.5 percent titanium, the other with 0.46 percent titanium and 0.07 percent zirconium) were fabricated from 1/2-inch-diameter rolled or swaged bars. All specimens were evaluated in short-time tensile tests in the as-received condition, and all except the molybdenum-titanium-zirconium alloy were tested after a 30-minute recrystallization anneal at 3800 F in a vacuum of approximately 0.1 micron. Results showed that the tungsten was considerably stronger than either the arc-cast unalloyed molybdenum or the molybdenum-base alloys over the 2500 to 3700 F temperature range. Recrystallization of swaged tungsten at 3800 F considerably reduced its tensile strength at 2500 F. However, above 3100 F, the as-swaged tungsten specimens recrystallized during testing, and had about the same strength as when recrystallized at 3800 F before evaluation. The ductility of molybdenum-base materials was very high at all test temperatures; the ductility of tungsten decreased sharply above about 3120 F.

Surface quality and microstructure of low-vacuum sintered orthodontic bracket 17-4 PH stainless steel fabricated by MIM process

NASA Astrophysics Data System (ADS)

Suharno, Bambang; Suharno, Lingga Pradinda; Saputro, Hantoro Restucondro; Irawan, Bambang; Prasetyadi, Tjokro; Ferdian, Deni; Supriyadi, Sugeng

2018-02-01

Surface roughness and microstructure play important role on orthodontic bracket quality. Therefore, orthodontic brackets need to have smooth surface roughness to reduce the friction and bacterial adhesion. Microstructure of orthodontic brackets also determine the mechanical properties and corrosion resistance. There are two methods to produce orthodontic bracket, investment casting and metal injection molding. The purpose of this study is to observe the surface roughness and microstructure of orthodontic bracket which were made from two different fabrication methods. To produce orthodontic bracket with metal injection molding method, 17-4 PH stainless steel feedstock was injected to the orthodontic bracket mold using injection molding machine. After injection, the binder was eliminated with solvent and thermal debinding. Solvent debinding process was conducted with hexane at 50 °C on magnetic stirrer for 1.5 hours. Thermal debinding process was conducted at 510 °C with 0.5 °C/min heat rate and 120 min holding time. Hereafter, sintering process were performed with vacuum tube furnace at 1360 °C with heat rate 5 °C/min and 90 min holding time in low vacuum atmosphere. To produce orthodontic bracket with investment casting method, the wax was injected into the mold then the wax pattern was arranged into the tree form. The tree form was then dipped into ceramic slurry and allowed to harden, the ceramic slurry has a thickness in the region of 10 mm. The ceramic mold was then heated at a temperature of over than 1100°C to strengthen the ceramic mold and to remove the remaining wax. After that, the molten 17-4 PH stainless steel was poured into the ceramic mold at a temperature of over 1600°C. The natural cooling process was carried out at temperature of 25°C, after which the ceramic mold was broken away. Then, the orthodontic bracket was cut from the tree form. The results show that the orthodontic bracket which were made with investment casting fabrication method have low porosity, high density, and there is no indication of secondary phase on the microstructure. However, it has rough brackets surface. Whereas, the production of orthodontic brackets using metal injection molding method resulted in better surface roughness. But, it has relatively high porosity, presence of another phase on the microstructure, and low density.

TiC reinforced cast Cr steels

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dogan, O.N.; Hawk, J.A.; Schrems, K.K.

2006-06-01

A new class of materials, namely TiC-reinforced cast chromium (Cr) steels, was developed for applications requiring high abrasion resistance and good fracture toughness. The research approach was to modify the carbide structure of commercial AISI 440C steel for better fracture resistance while maintaining the already high abrasion resistance. The new alloys contained 12Cr, 2.5–4.5Ti, and 1–1.5C (wt.%) and were melted in a vacuum induction furnace. Their microstructure was composed primarily of a martensitic matrix with a dispersion of TiC precipitates. Modification of TiC morphology was accomplished through changing the cooling rate during solidification. Wear rates of the TiC-reinforced Cr steelsmore » were comparable to that of AISI 440C steel, but the impact resistance was much improved.« less

CAST constraints on the axion-electron coupling

DOE PAGES

None, None

2013-05-09

In non-hadronic axion models, which have a tree-level axion-electron interaction, the Sun produces a strong axion flux by bremsstrahlung, Compton scattering, and axio- recombination, the “BCA processes.” Based on a new calculation of this flux, including for the first time axio-recombination, we derive limits on the axion-electron Yukawa coupling g ae and axion-photon interaction strength g aγ using the CAST phase-I data (vacuum phase). For m a ≲ 10 meV/c 2 we find g aγ gae < 8.1 × 10–23 GeV–1 at 95% CL. We stress that a next-generation axion helioscope such as the proposed IAXO could push this sensitivitymore » into a range beyond stellar energy-loss limits and test the hypothesis that white-dwarf cooling is dominated by axion emission.« less

On the phase evolution of AlCoCrCuFeMnSix high entropy alloys prepared by mechanical alloying and arc melting route

NASA Astrophysics Data System (ADS)

Kumar, Anil; Chopkar, Manoj

2018-05-01

Effect of Si addition on phase formation of AlCoCrCuFeMnSix (x=0, 0.3, 0.6 and 0.9) high entropy alloy have been investigated in this work. The alloys are prepared by mechanical alloying and vacuum arc melting technique. The X-ray diffraction results reveals the formation of mixture of face centered and body centered cubic solid solution phases in milled powders. The addition of Si favours body centered cubic structure formation during milling process. Whereas, after melting the milled powders, body centered phases formed during milling is partial transformed into sigma phases. XRD results were also correlated with the SEM elemental mapping of as casted samples. Addition of Si favours σ phase formation in the as cast samples.

Advanced Main Combustion Chamber structural jacket strength analysis

NASA Astrophysics Data System (ADS)

Johnston, L. M.; Perkins, L. A.; Denniston, C. L.; Price, J. M.

1993-04-01

The structural analysis of the Advanced Main Combustion Chamber (AMCC) is presented. The AMCC is an advanced fabrication concept of the Space Shuttle Main Engine main combustion chamber (MCC). Reduced cost and fabrication time of up to 75 percent were the goals of the AMCC with cast jacket with vacuum plasma sprayed or platelet liner. Since the cast material for the AMCC is much weaker than the wrought material for the MCC, the AMCC is heavier and strength margins much lower in some areas. Proven hand solutions were used to size the manifolds cutout tee areas for combined pressure and applied loads. Detailed finite element strength analyses were used to size the manifolds, longitudinal ribs, and jacket for combined pressure and applied local loads. The design of the gimbal actuator strut attachment lugs were determined by finite element analyses and hand solutions.

Cast erosion from the cleaning of debris after the use of a cast trimmer.

PubMed

Hansen, Paul A; Beatty, Mark W

2017-02-01

Whether using tap water to rinse off debris will make a clinical difference to the surface detail of a gypsum cast is unknown. In addition, how best to remove debris from the cast is unknown. The purpose of this in vitro study was to evaluate the efficiency of different methods of cleaning a gypsum cast after trimming and the effect of short-term exposure to tap water on the surface quality of the cast. A die fitting American National Standards Institute/American Dental Association specification 25 (International Standards Organization specification 6873) for dental gypsum products was embedded in a Dentoform with the machined lines positioned at the same level as the occlusal surface of the posterior teeth. A flat plate was used to ensure that the plane of occlusion for the die was at the same position as the posterior teeth. Forty polyvinyl siloxane impressions of the Dentoform were made and poured with vacuum-mixed improved Type IV dental stone. Each cast was inspected for the accurate reproduction of the lines. The base of the 2-stage pour was trimmed with a cast trimmer with water, and surface debris was removed by rinsing by hand under tap water for 10 seconds, by brushing the cast with a soft toothbrush for 10 seconds, or by resoaking the cast and using a soft camel hair brush in slurry water for 10 seconds. The amount of debris was evaluated on a scale of 1 to 4, and the quality of the 20-μm line was evaluated on a scale of 1 to 4 under ×15 magnification. The nonparametric Kruskal-Wallis ranks test was used to identify significant differences among the different cleaning methods (α=.05). Results of the Kruskal-Wallis and Kruskal-Wallis Z-value tests demonstrated that all cleaning methods produced cleaner casts than were observed for uncleansed controls (P<.001), but no differences in debris removal were found among the different cleaning methods (.065≤P≤.901). The ability to see the quality of a 20-μm line (P=.974) was not statistically different among the groups. Rinsing the cast under flowing tap water and brushing, or hand washing under flowing tap water, or using a soft camel hair brush in slurry water for 10 seconds had no noticeable effects on the quality of a 20-μm line, and all 3 methods resulted in a clean cast. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Formation of β-NiAl Phase During Casting of a Ni-Based Superalloy

NASA Astrophysics Data System (ADS)

Detrois, Martin; Jablonski, Paul D.

2018-04-01

A high-refractory Ni-based superalloy prototype was melted on a research scale while simulating industry practices. Ingots were vacuum induction melted and subjected to a computationally optimized homogenization heat treatment prior to fabrication which consisted of forging and hot rolling. Failure of one of the ingots at the early stage of the forging process was attributed to the precipitation of the β-NiAl phase during melting which stabilized the eutectic constituent.

Vacuum thermal evaporation of polyaniline doped with camphor sulfonic acid

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boyne, Devon; Menegazzo, Nicola; Pupillo, Rachel C.

2015-05-15

Intrinsically conducting polymers belong to a class of organic polymers with intriguing electronic and physical properties specifically for electro-optical applications. Significant interest into doped polyaniline (PAni) can be attributed to its high conductivity and environmental stability. Poor dissolution in most solvents has thus far hindered the successful integration of PAni into commercial applications, which in turn, has led to the investigations of various deposition and acidic doping methods. Physical vapor deposition methods, including D.C. magnetron sputtering and vacuum thermal evaporation, have shown exceptional control over physical film properties (thickness and morphology). However, resulting films are less conductive than films depositedmore » by conventional methods (i.e., spin and drop casting) due to interruption of the hyperconjugation of polymer chains. Specifically, vacuum thermal evaporation requires a postdoping process, which results in incorporation of impurities and oxidation of surface moieties. In this contribution, thermally evaporated films, sequentially doped by vacuum evaporation of an organic acid (camphorsulfonic acid, CSA) is explored. Spectroscopic evidence confirms the successful doping of PAni with CSA while physical characterization (atomic force microscopy) suggests films retain good morphology and are not damaged by the doping process. The procedure presented herein also combines other postpreparation methods in an attempt to improve conductivity and/or substrate adhesion.« less

Scalable Production Method for Graphene Oxide Water Vapor Separation Membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fifield, Leonard S.; Shin, Yongsoon; Liu, Wei

ABSTRACT Membranes for selective water vapor separation were assembled from graphene oxide suspension using techniques compatible with high volume industrial production. The large-diameter graphene oxide flake suspensions were synthesized from graphite materials via relatively efficient chemical oxidation steps with attention paid to maintaining flake size and achieving high graphene oxide concentrations. Graphene oxide membranes produced using scalable casting methods exhibited water vapor flux and water/nitrogen selectivity performance meeting or exceeding that of membranes produced using vacuum-assisted laboratory techniques. (PNNL-SA-117497)

The Extra Flask

NASA Astrophysics Data System (ADS)

Thielemann, R.

1981-05-01

It seemed quite natural and logical for me to want to address such an informed group about some of the many superalloys developed over the past forty years-but then I realized that most, if not all of them are listed with their compositions and properties in the ASM Metals Handbook, so this subject did not seem promising. At this point I started to think about the many new and important developments in processing techniques that made the melting, casting, and forming of the alloys possible. It seemed to me that the new procedures were, in most every instance, just as important as the new compositions themselves. Without the new techniques, many of the higher strength compositions were difficult, if not impossible to produce by existing procedures. Certainly, vacuum induction melting allowed us to melt and cast the titanium-and aluminum-bearing compositions without incurring the usual oxide and nitride inclusions.

Development of exothermically cast single-crystal Mar-M 247 and derivative alloys

NASA Technical Reports Server (NTRS)

Strangman, T. E.; Hoppin, G. S., III; Phipps, C. M.; Harris, K.; Schwer, R. E.

1980-01-01

A low-cost, exothermic directional-solidification (DS) process was developed to produce single-crystal (SC) Mar-M 247 high-pressure turbine blades. Stress-rupture data indicated that SC Mar-M 247 provides only marginal improvements in longitudinal strength relative to the columnar grained DS material. Removal of grain boundary strengthening elements (B, C, Zr, Hf) from the Mar-M 247 composition (which are also melting point depressants) permitted the alloy to be solutioned at significantly higher temperatures. An order of magnitude improvement in rupture life relative to SC Mar-M 247 was observed for several derivative alloys at 103.5 MPa (15 KSI) and 1093 C. Rupture lives of the modified SC alloys were significantly affected by both alloy purity and heat treatment. Critical aspects of vacuum induction refining, exothermic casting technology, alloy development and heat treatment, which contributed to this new class of turbine blades, are reviewed

A novel approach to fabrication of three-dimensional porous titanium with controllable structure.

PubMed

Wang, Dong; Li, Qiuyan; Xu, Mingqin; Jiang, Guofeng; Zhang, Yunxia; He, Guo

2017-02-01

A new approach to fabrication of porous titanium by using the molybdenum wire as space holder was developed, in which titanium liquid was cast into the entangled molybdenum wires in a vacuum environment, and followed by etching off the space holder material in an aqua regia solution. This infiltration casting and acid corrosion method fabricated the porous titanium with different porosities with a pore diameter of 0.4mm. The porous titanium with the porosity of 32-47% exhibited the Young's modulus in the range of 23-62GPa and the yielding strength in the range of 76-192MPa. The adhesion and spreadability of the bovine osteoblast cells on the porous titanium were also evaluated in vitro. The porous titanium with 47% porosity has great potential for implant applications. Copyright © 2016 Elsevier B.V. All rights reserved.

Off-loading strategies in diabetic foot syndrome-evaluation of different devices.

PubMed

Götz, Jürgen; Lange, Mario; Dullien, Silvia; Grifka, Joachim; Hertel, Gernot; Baier, Clemens; Koeck, Franz

2017-02-01

Diabetic foot syndrome is one of the most dreaded complications in diabetes mellitus. The purpose of this study was to assess the value of different offloading devices compared to walking in barefoot condition and in normal shoes both in healthy subjects and in patients with diabetes and neuropathy. Twenty patients with diabetes and polyneuropathy and ten healthy probands were included. Pedobarographic examination was performed in barefoot condition, with sneakers, postoperative shoes, Aircast® Diabetic Pneumatic Walker™ and VACO®diaped. In the diabetic group, a total contact cast was additionally tested. The most effective reduction of force was achieved by TCC (75%) and VACOdiaped (64.3%) with the VACO®diaped resulting in the most homogeneous distribution of forces all over the foot. A customized device like the TCC is still the most proven offloading device. However, a removable cast walker being based on vacuum pads and a cushioning sole, provides better results concerning force distribution.

Vacuum-processed polyethylene as a dielectric for low operating voltage organic field effect transistors

PubMed Central

Kanbur, Yasin; Irimia-Vladu, Mihai; Głowacki, Eric D.; Voss, Gundula; Baumgartner, Melanie; Schwabegger, Günther; Leonat, Lucia; Ullah, Mujeeb; Sarica, Hizir; Erten-Ela, Sule; Schwödiauer, Reinhard; Sitter, Helmut; Küçükyavuz, Zuhal; Bauer, Siegfried; Sariciftci, Niyazi Serdar

2012-01-01

We report on the fabrication and performance of vacuum-processed organic field effect transistors utilizing evaporated low-density polyethylene (LD-PE) as a dielectric layer. With C60 as the organic semiconductor, we demonstrate low operating voltage transistors with field effect mobilities in excess of 4 cm2/Vs. Devices with pentacene showed a mobility of 0.16 cm2/Vs. Devices using tyrian Purple as semiconductor show low-voltage ambipolar operation with equal electron and hole mobilities of ∼0.3 cm2/Vs. These devices demonstrate low hysteresis and operational stability over at least several months. Grazing-angle infrared spectroscopy of evaporated thin films shows that the structure of the polyethylene is similar to solution-cast films. We report also on the morphological and dielectric properties of these films. Our experiments demonstrate that polyethylene is a stable dielectric supporting both hole and electron channels. PMID:23483783

Microstructure of Haynes® 282® Superalloy after Vacuum Induction Melting and Investment Casting of Thin-Walled Components.

PubMed

Matysiak, Hubert; Zagorska, Malgorzata; Andersson, Joel; Balkowiec, Alicja; Cygan, Rafal; Rasinski, Marcin; Pisarek, Marcin; Andrzejczuk, Mariusz; Kubiak, Krzysztof; Kurzydlowski, Krzysztof J

2013-11-01

The aim of this work was to characterize the microstructure of the as-cast Haynes ® 282 ® alloy. Observations and analyses were carried out using techniques such as X-ray diffraction (XRD), light microscopy (LM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray spectroscopy (EDS), wave length dispersive X-ray spectroscopy (WDS), auger electron spectroscopy (AES) and electron energy-loss spectrometry (EELS). The phases identified in the as-cast alloy include: γ (gamma matrix), γ' (matrix strengthening phase), (TiMoCr)C (primary carbide), TiN (primary nitride), σ (sigma-TCP phase), (TiMo)₂SC (carbosulphide) and a lamellar constituent consisting of molybdenum and chromium rich secondary carbide phase together with γ phase. Within the dendrites the γ' appears mostly in the form of spherical, nanometric precipitates (74 nm), while coarser (113 nm) cubic γ' precipitates are present in the interdendritic areas. Volume fraction content of the γ' precipitates in the dendrites and interdendritic areas are 9.6% and 8.5%, respectively. Primary nitrides metallic nitrides (MN), are homogeneously dispersed in the as-cast microstructure, while primary carbides metallic carbides (MC), preferentially precipitate in interdendritic areas. Such preference is also observed in the case of globular σ phase. Lamellar constituents characterized as secondary carbides/γ phases were together with (TiMo)₂SC phase always observed adjacent to σ phase precipitates. Crystallographic relations were established in-between the MC, σ, secondary carbides and γ/γ' matrix.

Quantification of rectifications for the Northwestern University Flexible Sub-Ischial Vacuum Socket.

PubMed

Fatone, Stefania; Johnson, William Brett; Tran, Lilly; Tucker, Kerice; Mowrer, Christofer; Caldwell, Ryan

2017-06-01

The fit and function of a prosthetic socket depend on the prosthetist's ability to design the socket's shape to distribute load comfortably over the residual limb. We recently developed a sub-ischial socket for persons with transfemoral amputation: the Northwestern University Flexible Sub-Ischial Vacuum Socket. This study aimed to quantify the rectifications required to fit the Northwestern University Flexible Sub-Ischial Vacuum Socket to teach the technique to prosthetists as well as provide a computer-aided design-computer-aided manufacturing option. Development project. A program was used to align scans of unrectified and rectified negative molds and calculate shape change as a result of rectification. Averaged rectifications were used to create a socket template, which was shared with a central fabrication facility engaged in provision of Northwestern University Flexible Sub-Ischial Vacuum Sockets to early clinical adopters. Feedback regarding quality of fitting was obtained. Rectification maps created from 30 cast pairs of successfully fit Northwestern University Flexible Sub-Ischial Vacuum Sockets confirmed that material was primarily removed from the positive mold in the proximal-lateral and posterior regions. The template was used to fabricate check sockets for 15 persons with transfemoral amputation. Feedback suggested that the template provided a reasonable initial fit with only minor adjustments. Rectification maps and template were used to facilitate teaching and central fabrication of the Northwestern University Flexible Sub-Ischial Vacuum Socket. Minor issues with quality of initial fit achieved with the template may be due to inability to adjust the template to patient characteristics (e.g. tissue type, limb shape) and/or the degree to which it represented a fully mature version of the technique. Clinical relevance Rectification maps help communicate an important step in the fabrication of the Northwestern University Flexible Sub-Ischial Vacuum Socket facilitating dissemination of the technique, while the average template provides an alternative fabrication option via computer-aided design-computer-aided manufacturing and central fabrication.

Optimization of Multilayer Laminated Film and Absorbent of Vacuum Insulation Panel for Use at High Temperature

NASA Astrophysics Data System (ADS)

Araki, Kuninari; Echigoya, Wataru; Tsuruga, Toshimitsu; Kamoto, Daigorou; Matsuoka, Shin-Ichi

For the energy saving regulation and larger capacity, Vacuum Insulation Panel (VIP) has been used in refrigerators with urethane foam in recent years. VIP for low temperature is constructed by laminated plastic film, using heat welding of each neighboring part for keeping vacuum, so that the performance decrement is very large under high temperature. But recently high efficiency insulation material is desired for high temperature water holding devices (automatic vending machine, heat pump water heater, electric hot-water pot water, etc.), and we especially focused on cost and ability of the laminated plastic film and absorbent for high temperature VIP. We measured the heatproof temperature of plastic films and checked the amount of water vapor and out coming gas on temperature-programmed adsorption in absorbent. These results suggest the suitable laminated film and absorbent system for VIP use at high temperature, and the long-term reliability was evaluated by measuring thermal conductivity of high temperature. As a result it was found that high-retort pouch of CPP (cast polypropylene film) and adding of aluminum coating are the most suitable materials for use in the welded layers of high-temperature VIPs (105°C).

Welding wire selection critical to jet engine repair work

NASA Astrophysics Data System (ADS)

1992-11-01

A review is provided of issues related to the selection of welding wire for aircraft gas-turbine engines emphasizing the importance of cleanliness in the welding wire product. A three-step metallurgical control process is described for the production of welding wire that is clean and suitable for turbine repair. The process is based on: (1) vacuum induction melting; (2) contamination-free processing of the wire; and (3) environmentally controlled packaging. Weld work on aerospace casting is shown to be useful and suitable for many alloy and superalloy materials with various filler materials.

Surface Characterization of New Biomaterials

NASA Astrophysics Data System (ADS)

Minciuna, M. G.; Vizureanu, P.; Abdullah, M. M. B.; Achitei, D. C.; Istrate, B.; Cimpoesu, R.; Focsaneanu, S. C.

2017-06-01

This paper presents the characterization of new alloys CoCrMoSi6, CoCrMoSi7, CoCrMoSi10, in terms of hardness determinations, fractographic analysis and surface analysis. The original version of the alloy was obtained by casting process in a vacuum arc furnace. Experimental results obtained from this study confirms that by increasing content of silicon, the mechanical properties are superior and the positive results obtained at surface studies favoring the formation of compounds, that lead to the reduction of alloying grade for α solid solution and the plasticity of the alloys.

Process for alloying uranium and niobium

DOEpatents

Holcombe, Cressie E.; Northcutt, Jr., Walter G.; Masters, David R.; Chapman, Lloyd R.

1991-01-01

Alloys such as U-6Nb are prepared by forming a stacked sandwich array of uraniun sheets and niobium powder disposed in layers between the sheets, heating the array in a vacuum induction melting furnace to a temperature such as to melt the uranium, holding the resulting mixture at a temperature above the melting point of uranium until the niobium dissolves in the uranium, and casting the uranium-niobium solution. Compositional uniformity in the alloy product is enabled by use of the sandwich structure of uranium sheets and niobium powder.

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

DOEpatents

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

1978-03-14

The invention consists of a method of producing a fine equiaxed grain structure (ASTM 2-4) in cast nickel-base superalloys which increases low cycle fatigue lives without detrimental effects on stress rupture properties to temperatures as high as 1800.degree. F. These superalloys are variations of the basic nickel-chromium matrix, hardened by gamma prime [Ni.sub.3 (Al, Ti)] but with optional additions of cobalt, tungsten, molybdenum, vanadium, columbium, tantalum, boron, zirconium, carbon and hafnium. The invention grain refines these alloys to ASTM 2 to 4 increasing low cycle fatigue life by a factor of 2 to 5 (i.e. life of 700 hours would be increased to 1400 to 3500 hours for a given stress) as a result of the addition of 0.01% to 0.2% of a member of the group consisting of boron, zirconium and mixtures thereof to aid heterogeneous nucleation. The alloy is vacuum melted and heated to 250.degree.-400.degree. F. above the melting temperature, cooled to partial solidification, thus resulting in said heterogeneous nucleation and fine grains, then reheated and cast at about 50.degree.-100.degree. F. of superheat. Additions of 0.1% boron and 0.1% zirconium (optional) are the preferred nucleating agents.

Fracture Toughness and Fatigue Crack Growth Behavior of As-Cast High-Entropy Alloys

NASA Astrophysics Data System (ADS)

Seifi, Mohsen; Li, Dongyue; Yong, Zhang; Liaw, Peter K.; Lewandowski, John J.

2015-08-01

The fracture toughness and fatigue crack growth behavior of two as-vacuum arc cast high-entropy alloys (HEAs) (Al0.2CrFeNiTi0.2 and AlCrFeNi2Cu) were determined. A microstructure examination of both HEA alloys revealed a two-phase structure consisting of body-centered cubic (bcc) and face-centered cubic (fcc) phases. The notched and fatigue precracked toughness values were in the range of those reported in the literature for two-phase alloys but significantly less than recent reports on a single phase fcc-HEA that was deformation processed. Fatigue crack growth experiments revealed high fatigue thresholds that decreased significantly with an increase in load ratio, while Paris law slopes exhibited metallic-like behavior at low R with significant increases at high R. Fracture surface examinations revealed combinations of brittle and ductile/dimpled regions at overload, with some evidence of fatigue striations in the Paris law regime.

Microstructure and Magnetic Properties of Optimally Annealed Ni43Mn41Co5Sn11Heusler Alloy

NASA Astrophysics Data System (ADS)

Elwindari, Nastiti; Kurniawan, Budhy; Kurniawan, Candra; Manaf, Azwar

2017-05-01

In this work, synthesis and characterization of a polycrystalline Ni43Mn41Co5Sn11 (NMCS) alloy are reported. Alloy preparation was conducted by melting the constituent components of the designated alloy under an inert Argon (Ar) atmosphere in a vacuum mini arc-melting furnace. Microstructure observation to the as-cast and annealed ingots showing dendritic structure in the as-cast sample. Series of annealing treatment to the sample at 1173 K have changed dendrites progressively in the homogeneous structure after 24 hours annealing time. The annealed sample consisted of a NiMnCoSn main phase with 99.3 % volume fraction. Hence, the 24 hours annealed ingot is a single phase alloy. The curie temperature of the annealed NMCS alloys was found in the range 348∼351 K. Loop hysteresis evaluation of the annealed ingots showed that ingot which annealed for 12 hours showed the largest magnetization value of 57.96 emu/g.

Heat Treatment Development for a Rapidly Solidified Heat Resistant Cast Al-Si Alloy

NASA Astrophysics Data System (ADS)

Kasprzak, W.; Chen, D. L.; Shaha, S. K.

2013-07-01

Existing heat treatment standards do not properly define tempers for thin-walled castings that solidified with high solidification rates. Recently emerged casting processes such as vacuum high pressure die casting should not require long solution treatment times due to the fine microstructures arising from rapid solidification rates. The heat treatment studies involving rapidly solidified samples with secondary dendrite arm spacing between 10 and 35 μm were conducted for solution times between 30 min and 9 h and temperatures of 510 and 525 °C and for various aging parameters. The metallurgical analysis revealed that an increase in microstructure refinement could enable a reduction of solution time up to 88%. Solution treatment resulted in the dissolution of Al2Cu and Al5Mg8Si6Cu2, while Fe- and TiZrV-based phases remained partially in the microstructure. The highest strength of approximately 351 ± 9.7 and 309 ± 3.4 MPa for the UTS and YS, respectively, was achieved for a 2-step solution treatment at 510 and 525 °C in the T6 peak aging conditions, i.e., 150 °C for 100 h. The T6 temper did not yield dimensionally stable microstructure since exceeding 250 °C during in-service operation could result in phase transformation corresponding to the over-aging reaction. The microstructure refinement had a statistically stronger effect on the alloy strength than the increase in solutionizing time. Additionally, thermal analysis and dilatometer results were presented to assess the dissolution of phases during solution treatment, aging kinetics as well as dimensional stability.

Ultra-high vacuum compatible preparation chain for intermetallic compounds

NASA Astrophysics Data System (ADS)

Bauer, A.; Benka, G.; Regnat, A.; Franz, C.; Pfleiderer, C.

2016-11-01

We report the development of a versatile material preparation chain for intermetallic compounds, which focuses on the realization of a high-purity growth environment. The preparation chain comprises an argon glovebox, an inductively heated horizontal cold boat furnace, an arc melting furnace, an inductively heated rod casting furnace, an optically heated floating-zone furnace, a resistively heated annealing furnace, and an inductively heated annealing furnace. The cold boat furnace and the arc melting furnace may be loaded from the glovebox by means of a load-lock permitting to synthesize compounds starting with air-sensitive elements while handling the constituents exclusively in an inert gas atmosphere. All furnaces are all-metal sealed, bakeable, and may be pumped to ultra-high vacuum. We find that the latter represents an important prerequisite for handling compounds with high vapor pressure under high-purity argon atmosphere. We illustrate the operational aspects of the preparation chain in terms of the single-crystal growth of the heavy-fermion compound CeNi2Ge2.

Semiconductor surface protection material

NASA Technical Reports Server (NTRS)

Packard, R. D. (Inventor)

1973-01-01

A method and a product for protecting semiconductor surfaces is disclosed. The protective coating material is prepared by heating a suitable protective resin with an organic solvent which is solid at room temperature and converting the resulting solution into sheets by a conventional casting operation. Pieces of such sheets of suitable shape and thickness are placed on the semiconductor areas to be coated and heat and vacuum are then applied to melt the sheet and to drive off the solvent and cure the resin. A uniform adherent coating, free of bubbles and other defects, is thus obtained exactly where it is desired.

[Rapid prototyping: a very promising method].

PubMed

Haverman, T M; Karagozoglu, K H; Prins, H-J; Schulten, E A J M; Forouzanfar, T

2013-03-01

Rapid prototyping is a method which makes it possible to produce a three-dimensional model based on two-dimensional imaging. Various rapid prototyping methods are available for modelling, such as stereolithography, selective laser sintering, direct laser metal sintering, two-photon polymerization, laminated object manufacturing, three-dimensional printing, three-dimensional plotting, polyjet inkjet technology,fused deposition modelling, vacuum casting and milling. The various methods currently being used in the biomedical sector differ in production, materials and properties of the three-dimensional model which is produced. Rapid prototyping is mainly usedforpreoperative planning, simulation, education, and research into and development of bioengineering possibilities.

Encapsulation for smart textile electronics - humidity and temperature sensor.

PubMed

Larsson, Andreas; Tran, Thanh-Nam; Aasmundtveit, Knut E; Seeberg, Trine M

2015-01-01

A combined humidity and temperature sensor was packaged by vacuum casting onto three different types of textiles; cotton, nylon and a waterproof fabric. This was done in order to integrate the sensor in a jacket in a soft and reliable way without changing the sensor performance. A membrane was custom made and integrated into the device to protect the sensor from the environment. The packaged sensors performance was characterized in a climate chamber were the relative humidity and temperature ranged from 25 % to 95 % and -10 °C to 75 °C respectively. The packaged sensors showed insignificant to limited performance degradation.

The effect of coating patterns with spinel-based investment on the castability and porosity of titanium cast into three phosphate-bonded investments.

PubMed

Pieralini, Anelise R F; Benjamin, Camila M; Ribeiro, Ricardo Faria; Scaf, Gulnara; Adabo, Gelson Luis

2010-10-01

This study evaluated the effect of pattern coating with spinel-based investment Rematitan Ultra (RU) on the castability and internal porosity of commercially pure (CP) titanium invested into phosphate-bonded investments. The apparent porosity of the investment was also measured. Square patterns (15 × 15 × 0.3 mm(3)) were either coated with RU, or not and invested into the phosphate-bonded investments: Rematitan Plus (RP), Rema Exakt (RE), Castorit Super C (CA), and RU (control group). The castings were made in an Ar-arc vacuum-pressure machine. The castability area (mm(2) ) was measured by an image-analysis system (n = 10). For internal porosity, the casting (12 × 12 × 2 mm(3) ) was studied by the X-ray method, and the projected porous area percentage was measured by an image-analysis system (n = 10). The apparent porosity of the investment (n = 10) was measured in accordance with the ASTM C373-88 standard. Analysis of variance (One-way ANOVA) of castability was significant, and the Tukey test indicated that RU had the highest mean but the investing technique with coating increased the castability for all phosphate-bonded investments. The analysis of the internal porosity of the cast by the nonparametric test demonstrated that the RP, RE, and CA with coating and RP without coating did not differ from the control group (RU), while the CA and RE casts without coating were more porous. The one-way ANOVA of apparent porosity of the investment was significant, and the Tukey test showed that the means of RU (36.10%) and CA (37.22%) were higher than those of RP (25.91%) and RE (26.02%). Pattern coating with spinel-based material prior to phosphate-bonded investments can influence the castability and the internal porosity of CP Ti. © 2010 by The American College of Prosthodontists.

Oxidation characteristics of porous-nickel prepared by powder metallurgy and cast-nickel at 1273 K in air for total oxidation time of 100 h.

PubMed

Mohamed, Lamiaa Z; Ghanem, Wafaa A; El Kady, Omayma A; Lotfy, Mohamed M; Ahmed, Hafiz A; Elrefaie, Fawzi A

2017-11-01

The oxidation behavior of two types of inhomogeneous nickel was investigated in air at 1273 K for a total oxidation time of 100 h. The two types were porous sintered-nickel and microstructurally inhomogeneous cast-nickel. The porous-nickel samples were fabricated by compacting Ni powder followed by sintering in vacuum at 1473 K for 2 h. The oxidation kinetics of the samples was determined gravimetrically. The topography and the cross-section microstructure of each oxidized sample were observed using optical and scanning electron microscopy. X-ray diffractometry and X-ray energy dispersive analysis were used to determine the nature of the formed oxide phases. The kinetic results revealed that the porous-nickel samples had higher trend for irreproducibility. The average oxidation rate for porous- and cast-nickel samples was initially rapid, and then decreased gradually to become linear. Linear rate constants were 5.5 × 10 -8  g/cm 2  s and 3.4 × 10 -8  g/cm 2  s for the porous- and cast-nickel samples, respectively. Initially a single-porous non-adherent NiO layer was noticed on the porous- and cast-nickel samples. After a longer time of oxidation, a non-adherent duplex NiO scale was formed. The two layers of the duplex scales were different in color. NiO particles were observed in most of the pores of the porous-nickel samples. Finally, the linear oxidation kinetics and the formation of porous non-adherent duplex oxide scales on the inhomogeneous nickel substrates demonstrated that the addition of new layers of NiO occurred at the scale/metal interface due to the thermodynamically possible reaction between Ni and the molecular oxygen migrating inwardly.

Preparation of enhanced hydrophobic poly(L-lactide-co-ɛ-caprolactone) films surface and its blood compatibility

NASA Astrophysics Data System (ADS)

Kim, Seung Il; Lim, Jin Ik; Jung, Youngmee; Mun, Cho Hay; Kim, Ji Heung; Kim, Soo Hyun

2013-07-01

Hydrophobicity-enhanced poly(L-lactide-co-ɛ-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 1H 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 × 104, 1.2 × 105, 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.

Materials

NASA Technical Reports Server (NTRS)

Glaessgen, Edward H.; Schoeppner, Gregory A.

2006-01-01

NASA Langley Research Center has successfully developed an electron beam freeform fabrication (EBF3) process, a rapid metal deposition process that works efficiently with a variety of weldable alloys. The EBF3 process can be used to build a complex, unitized part in a layer-additive fashion, although the more immediate payoff is for use as a manufacturing process for adding details to components fabricated from simplified castings and forgings or plate products. The EBF3 process produces structural metallic parts with strengths comparable to that of wrought product forms and has been demonstrated on aluminum, titanium, and nickel-based alloys to date. The EBF3 process introduces metal wire feedstock into a molten pool that is created and sustained using a focused electron beam in a vacuum environment. Operation in a vacuum ensures a clean process environment and eliminates the need for a consumable shield gas. Advanced metal manufacturing methods such as EBF3 are being explored for fabrication and repair of aerospace structures, offering potential for improvements in cost, weight, and performance to enhance mission success for aircraft, launch vehicles, and spacecraft. Near-term applications of the EBF3 process are most likely to be implemented for cost reduction and lead time reduction through addition of details onto simplified preforms (casting or forging). This is particularly attractive for components with protruding details that would require a significantly large volume of material to be machined away from an oversized forging, offering significant reductions to the buy-to-fly ratio. Future far-term applications promise improved structural efficiency through reduced weight and improved performance by exploiting the layer-additive nature of the EBF3 process to fabricate tailored unitized structures with functionally graded microstructures and compositions.

Evaluation of Titanium Alloys Fabricated Using Rapid Prototyping Technologies—Electron Beam Melting and Laser Beam Melting

PubMed Central

Koike, Mari; Greer, Preston; Owen, Kelly; Lilly, Guo; Murr, Lawrence E.; Gaytan, Sara M.; Martinez, Edwin; Okabe, Toru

2011-01-01

This study characterized properties of Ti-6Al-4V ELI (extra low interstitial, ASTM grade 23) specimens fabricated by a laser beam melting (LBM) and an electron beam melting (EBM) system for dental applications. Titanium alloy specimens were made into required size and shape for each standard test using fabrication methods. The LBM specimens were made by an LBM machine utilizing 20 µm of Ti-6Al-4V ELI powder. Ti-6Al-4V ELI specimens were also fabricated by an EBM using 40 µm of Ti-6Al-4V ELI powder (average diameter, 40 µm: Arcam AB®) in a vacuum. As a control, cast Ti-6Al-4V ELI specimens (Cast) were made using a centrifugal casting machine in an MgO-based mold. Also, a wrought form of Ti-6Al-4V ELI (Wrought) was used as a control. The mechanical properties, corrosion properties and grindability (wear properties) were evaluated and data was analyzed using ANOVA and a non-parametric method (α = 0.05). The strength of the LBM and wrought specimens were similar, whereas the EBM specimens were slightly lower than those two specimens. The hardness of both the LBM and EBM specimens was similar and slightly higher than that of the cast and wrought alloys. For the higher grindability speed at 1,250 m/min, the volume loss of Ti64 LBM and EBM showed no significant differences among all the fabrication methods. LBM and EBM exhibited favorable results in fabricating dental appliances with excellent properties as found for specimens made by other fabricating methods. PMID:28824107

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

NASA Technical Reports Server (NTRS)

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

2012-01-01

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

Evaluation of Titanium Alloys Fabricated Using Rapid Prototyping Technologies-Electron Beam Melting and Laser Beam Melting.

PubMed

Koike, Mari; Greer, Preston; Owen, Kelly; Lilly, Guo; Murr, Lawrence E; Gaytan, Sara M; Martinez, Edwin; Okabe, Toru

2011-10-10

This study characterized properties of Ti-6Al-4V ELI (extra low interstitial, ASTM grade 23) specimens fabricated by a laser beam melting (LBM) and an electron beam melting (EBM) system for dental applications. Titanium alloy specimens were made into required size and shape for each standard test using fabrication methods. The LBM specimens were made by an LBM machine utilizing 20 µm of Ti-6Al-4V ELI powder. Ti-6Al-4V ELI specimens were also fabricated by an EBM using 40 µm of Ti-6Al-4V ELI powder (average diameter, 40 µm: Arcam AB Ò ) in a vacuum. As a control, cast Ti-6Al-4V ELI specimens (Cast) were made using a centrifugal casting machine in an MgO-based mold. Also, a wrought form of Ti-6Al-4V ELI (Wrought) was used as a control. The mechanical properties, corrosion properties and grindability (wear properties) were evaluated and data was analyzed using ANOVA and a non-parametric method (α = 0.05). The strength of the LBM and wrought specimens were similar, whereas the EBM specimens were slightly lower than those two specimens. The hardness of both the LBM and EBM specimens was similar and slightly higher than that of the cast and wrought alloys. For the higher grindability speed at 1,250 m/min, the volume loss of Ti64 LBM and EBM showed no significant differences among all the fabrication methods. LBM and EBM exhibited favorable results in fabricating dental appliances with excellent properties as found for specimens made by other fabricating methods.

Materials for Advanced Ultrasupercritical Steam Turbines Task 4: Cast Superalloy Development

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thangirala, Mani

The Steam Turbine critical stationary structural components are high integrity Large Shell and Valve Casing heavy section Castings, containing high temperature steam under high pressures. Hence to support the development of advanced materials technology for use in an AUSC steam turbine capable of operating with steam conditions of 760°C (1400°F) and 35 Mpa (5000 psia), Casting alloy selection and evaluation of mechanical, metallurgical properties and castability with robust manufacturing methods are mandated. Alloy down select from Phase 1 based on producability criteria and creep rupture properties tested by NETL-Albany and ORNL directed the consortium to investigate cast properties of Haynesmore » 282 and Haynes 263. The goals of Task 4 in Phase 2 are to understand a broader range of mechanical properties, the impact of manufacturing variables on those properties. Scale up the size of heats to production levels to facilitate the understanding of the impact of heat and component weight, on metallurgical and mechanical behavior. GE Power & Water Materials and Processes Engineering for the Phase 2, Task 4.0 Castings work, systematically designed and executed casting material property evaluation, multiple test programs. Starting from 15 lbs. cylinder castings to world’s first 17,000 lbs. poured weight, heavy section large steam turbine partial valve Haynes 282 super alloy casting. This has demonstrated scalability of the material for steam Turbine applications. Activities under Task 4.0, Investigated and characterized various mechanical properties of Cast Haynes 282 and Cast Nimonic 263. The development stages involved were: 1) Small Cast Evaluation: 4 inch diam. Haynes 282 and Nimonic 263 Cylinders. This provided effects of liquidus super heat range and first baseline mechanical data on cast versions of conventional vacuum re-melted and forged Ni based super alloys. 2) Step block castings of 300 lbs. and 600 lbs. Haynes 282 from 2 foundry heats were evaluated which demonstrated the importance of proper heat treat cycles for Homogenization, and Solutionizing parameters selection and implementation. 3) Step blocks casting of Nimonic 263: Carried out casting solidification simulation analysis, NDT inspection methods evaluation, detailed test matrix for Chemical, Tensile, LCF, stress rupture, CVN impact, hardness and J1C Fracture toughness section sensitivity data and were reported. 4) Centrifugal Casting of Haynes 282, weighing 1400 lbs. with hybrid mold (half Graphite and half Chromite sand) mold assembly was cast using compressor casing production tooling. This test provided Mold cooling rates influence on centrifugally cast microstructure and mechanical properties. Graphite mold section out performs sand mold across all temperatures for 0.2% YS; %Elongation, %RA, UTS at 1400°F. Both Stress-LMP and conditional Fracture toughness plots data were in the scatter band of the wrought alloy. 5) Fundamental Studies on Cooling rates and SDAS test program. Evaluated the influence of 6 mold materials Silica, Chromite, Alumina, Silica with Indirect Chills, Zircon and Graphite on casting solidification cooling rates. Actual Casting cooling rates through Liquidus to Solidus phase transition were measured with 3 different locations based thermocouples placed in each mold. Compared with solidification simulation cooling rates and measurement of SDAS, microstructure features were reported. The test results provided engineered casting potential methods, applicable for heavy section Haynes 282 castings for optimal properties, with foundry process methods and tools. 6) Large casting of Haynes 282 Drawings and Engineering FEM models and supplemental requirements with applicable specifications were provided to suppliers for the steam turbine proto type feature valve casing casting. Molding, melting and casting pouring completed per approved Manufacturing Process Plan during 2014 Q4. The partial valve casing was successfully cast after casting methods were validated with solidification simulation analysis and the casting met NDT inspection and acceptance criteria. Heat treated and sectioned to extract trepan samples at different locations comparing with cast on coupons test data. Material properties requisite for design, such as tensile, creep/rupture, LCF, Fracture Toughness, Charpy V-notch chemical analysis testing were carried out. The test results will be presented in the final report. The typical Haynes 282 large size Steam Turbine production casting from Order to Delivery foundry schedule with the activity break up is shown in Figures 107 and 108. • From Purchase Order placement to Casting pouring ~ 26 weeks. 1. Sales and commercial review 3 2. Engineering Drawings/models review 4 3. Pattern and core box manufacturing 6 4. Casting process engineering review 4 5. FEM and solidification simulation analysis 4 6. Gating & Feeder Attachments, Ceramic tiling 2 7. Molding and coremaking production scheduling 6 8. Melting planning and schedule 3 9. Pouring, cooling and shake out 2 • From Pouring to casting Delivery ~ 29 weeks 10. Shot blast and riser cutting, gates removal 3 11. Homogenizing , solutionizing HT furnace prep 4 12. Grinding, Fettling 2 13. Aging HT Cycle, cooling 2 14. VT and LPT NDT inspections 2 15. Radiographic inspection 4 16. Mechanical testing, Chemical analysis test certs 4 17. Casting weld repair upgrades and Aging PWHT 4 18. NDT after weld repairs and casting upgrades 3 19. Casting Final Inspection and test certifications 3 20. Package and delivery 2 Hence the Total Lead time from P.O to Casting delivery is approximately 55 weeks. The Task 4.2 and Task 4.3 activities and reporting completed.« less

Improved Interfacial Bonding in Magnesium/Aluminum Overcasting Systems by Aluminum Surface Treatments

NASA Astrophysics Data System (ADS)

Zhang, Hui; Chen, Yiqing; Luo, Alan A.

2014-12-01

"Overcasting" technique is used to produce bimetallic magnesium/aluminum (Mg/Al) structures where lightweight Mg can be cast onto solid Al substrates. An inherent difficulty in creating strong Mg/Al interfacial bonding is the natural oxide film on the solid Al surfaces, which reduces the wettability between molten Mg and Al substrates during the casting process. In the paper, an "electropolishing + anodizing" surface treatment has been developed to disrupt the oxide film on a dilute Al-0.08 wt pct Ga alloy, improving the metallurgical bonding between molten Mg and Al substrates in the bimetallic experiments carried out in a high-vacuum test apparatus. The test results provided valuable information of the interfacial phenomena of the Mg/Al bimetallic samples. The results show significantly improved metallurgical bonding in the bimetallic samples with "electropolishing + anodizing" surface treatment and Ga alloying. It is recommended to adjust the pre-heating temperature and time of the Al substrates and the Mg melt temperature to control the interfacial reactions for optimum interfacial properties in the actual overcasting processes.

Structure-property characterization of rheocast and VADER processed IN-100 superalloy. Ph.D. Thesis. Final Report

NASA Technical Reports Server (NTRS)

Cheng, J. J. A.; Apelian, D.

1985-01-01

Two recent solidification processes have been applied in the production of IN-100 nickel-base superalloy: rheocasting and vacuum arc double electrode remelting (VADER). A detailed microstructural examination has been made of the products of these two processes; associated tensile strength and fatigue crack propagation (FCP) rate at an elevated temperature were evaluated. In rheocasting, processing variables that have been evaluated include stirring speed, isothermal stirring time and volume fraction solid during isothermal stirring. VADER processed IN-100 was purchased from Special Metals Corp., New Hartford, NY. As-cast ingots were subjected to hot isostatic pressing (HIP) and heat treatment. Both rheocasting and VADER processed materials yield fine and equiaxed spherical structures, with reduced macrosegregation in comparison to ingot materials. The rheocast structures are discussed on the basis of the Vogel-Doherty-Cantor model of dendrite arm fragmentation. The rheocast ingots evaluated were superior in yield strength to both VADER and commercially cast IN-100 alloy. Rheocast and VADER ingots may have higher crack propagation resistance than P/M processed material.

Solid Insulated Switchgear and Investigation of its Mechanical and Electrical Reliability

NASA Astrophysics Data System (ADS)

Sato, Junichi; Kinoshita, Susumu; Sakaguchi, Osamu; Miyagawa, Masaru; Shimizu, Toshio; Homma, Mitsutaka

SF6 gas is applied widely to medium voltage switchgear because of its high insulation reliability and down-sizing ability. However, SF6 gas was placed on the list of greenhouse gases under the Kyoto Protocol in 1997. Since then, the investigation and development concerning SF6-free or less has carried out activity. Therefore, we paid attention to the solid material which has higher dielectric strength than SF6, and we have newly developed solid insulated switchgear (SIS) achieved by molding all main circuit. A new epoxy casting material is applied, which contains a great deal of spherical silica and a small amount of rubber particles. This new material has the high mechanical strength, high thermal resistance, high toughness, and also high dielectric strength because of directly molding the vacuum bottle, down-sizing and reliability. This paper describes about the technology of a new epoxy casting material which achieves the SIS. In addition, the mechanical and electrical reliability test of SIS applied a new epoxy resin are carried out, and effectiveness of the development material and the mechanical and electrical reliability of SIS are verified.

Fundamental technical elements of freeze-fracture/freeze-etch in biological electron microscopy.

PubMed

Carson, Johnny L

2014-09-11

Freeze-fracture/freeze-etch describes a process whereby specimens, typically biological or nanomaterial in nature, are frozen, fractured, and replicated to generate a carbon/platinum "cast" intended for examination by transmission electron microscopy. Specimens are subjected to ultrarapid freezing rates, often in the presence of cryoprotective agents to limit ice crystal formation, with subsequent fracturing of the specimen at liquid nitrogen cooled temperatures under high vacuum. The resultant fractured surface is replicated and stabilized by evaporation of carbon and platinum from an angle that confers surface three-dimensional detail to the cast. This technique has proved particularly enlightening for the investigation of cell membranes and their specializations and has contributed considerably to the understanding of cellular form to related cell function. In this report, we survey the instrument requirements and technical protocol for performing freeze-fracture, the associated nomenclature and characteristics of fracture planes, variations on the conventional procedure, and criteria for interpretation of freeze-fracture images. This technique has been widely used for ultrastructural investigation in many areas of cell biology and holds promise as an emerging imaging technique for molecular, nanotechnology, and materials science studies.

Approaches to Design and Evaluation of Sandwich Composites

NASA Technical Reports Server (NTRS)

Shivakumar, Kunigal; Raju, I. S. (Technical Monitor); Ambur, D. (Technical Monitor)

2001-01-01

This report describes research during the period June 15, 1997 to October 31, 2000. This grant yielded a low cast manufacturing of composite sandwich structures technology and characterization interfacial and subinterfacial cracks in foam core sandwich panels. The manufacturing technology is called the vacuum assisted resin transfer (VARTM). The VARTM is suitable for processing composite materials both at ambient and elevated temperatures and of unlimited component size. This technology has been successfully transferred to a small business fiber preform manufacturing company 3TEX located in Cary, North Carolina. The grant also supported one Ph.D, one M.S and a number of under graduate students, and nine publications and Presentations.

Development and quality assessments of commercial heat production of ATF FeCrAl tubes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamamoto, Yukinori

2015-09-01

Development and quality assessment of the 2 nd generation ATF FeCrAl tube production with commercial manufacturers were conducted. The manufacturing partners include Sophisticated Alloys, Inc. (SAI), Butler, PA for FeCrAl alloy casting via vacuum induction melting, Oak Ridge National Laboratory (ORNL) for extrusion process to prepare the master bars/tubes to be tube-drawn, and Rhenium Alloys, Inc. (RAI), North Ridgeville, OH, for tube-drawing process. The masters bars have also been provided to Los Alamos National Laboratory (LANL) who works with Century Tubes, Inc., (CTI), San Diego, CA, as parallel tube production effort under the current program.

Using of fiber-array diagnostic to measure the propagation of fast axial ionization wave during breakdown of electrically exploding tungsten wire in vacuum.

PubMed

Shi, Huantong; Zou, Xiaobing; Wang, Xinxin

2017-12-01

The physical process of electrical explosion of wires in vacuum is featured with the surface discharge along the wire, which generates the corona plasma layer and terminates the Joule heating of the wire core. In this paper, a fiber-array probe was designed to directly measure the radiation of surface arc with spatial and temporal resolution. The radiation of the exploding wire was casted to the section of an optical-fiber-array by a lens and transmitted to PIN diodes and finally collected with an oscilloscope. This probe enables direct diagnostics of the evolution of surface discharge with high temporal resolution and certain spatial resolution. The radiation of a tungsten wire driven by a positive current pulse was measured, and results showed that surface discharge initiates near the cathode and propagates toward the anode with a speed of 7.7 ± 1.6 mm/ns; further estimations showed that this process is responsible for the "conical" structure of the exploding wire.

Using of fiber-array diagnostic to measure the propagation of fast axial ionization wave during breakdown of electrically exploding tungsten wire in vacuum

NASA Astrophysics Data System (ADS)

Shi, Huantong; Zou, Xiaobing; Wang, Xinxin

2017-12-01

The physical process of electrical explosion of wires in vacuum is featured with the surface discharge along the wire, which generates the corona plasma layer and terminates the Joule heating of the wire core. In this paper, a fiber-array probe was designed to directly measure the radiation of surface arc with spatial and temporal resolution. The radiation of the exploding wire was casted to the section of an optical-fiber-array by a lens and transmitted to PIN diodes and finally collected with an oscilloscope. This probe enables direct diagnostics of the evolution of surface discharge with high temporal resolution and certain spatial resolution. The radiation of a tungsten wire driven by a positive current pulse was measured, and results showed that surface discharge initiates near the cathode and propagates toward the anode with a speed of 7.7 ± 1.6 mm/ns; further estimations showed that this process is responsible for the "conical" structure of the exploding wire.

Application of powder metallurgy technique to produce improved bearing elements for cryogenic aerospace engine turbopumps

NASA Technical Reports Server (NTRS)

Moxson, V. S.; Moracz, D. J.; Bhat, B. N.; Dolan, F. J.; Thom, R.

1987-01-01

Traditionally, vacuum melted 440C stainless steel is used for high performance bearings for aerospace cryogenic systems where corrosion due to condensation is a major concern. For the Space Shuttle Main Engine (SSME), however, 440C performance in the high-pressure turbopumps has been marginal. A basic assumption of this study was that powder metallurgy, rather than cast/wrought, processing would provide the finest, most homogeneous bearing alloy structure. Preliminary testing of P/M alloys (hardness, corrosion resistance, wear resistance, fatigue resistance, and fracture toughness) was used to 'de-select' alloys which did perform as well as baseline 440C. Five out of eleven candidate materials (14-4/6V, X-405, MRC-2001, T-440V, and D-5) based on preliminary screening were selected for the actual rolling-sliding five-ball testing. The results of this test were compared with high-performance vacuum-melted M50 bearing steel. The results of the testing indicated outstanding performance of two P/M alloys, X-405 and MRC-2001, which eventually will be further evaluated by full-scale bearing testing.

Credit BG. This view looks northwest (290°) in the mixer ...

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

Credit BG. This view looks northwest (290°) in the mixer room at the 30-gallon Baker-Perkins model 121/2 PVM mixer and its associated equipment. The hopper in the left background feeds ingredients to the mixing pot when the hopper is mounted on the mixer frame; the hoist overhead is used to mount the hopper. The mixing pot is in its lowered position beneath the mixer blades. The pot is normally raised and secured to the upper half of the mixer, and a vacuum is applied during mixing operations to prevent the entrainment of air bubbles in the mix. A second mixing pot appears in the right background, and a pot vacuum lid appears in the extreme right foreground. The equipment on the palette in the left foreground is not related to the mixer. Note the explosion-proof fluorescent lighting fixtures suspended from the ceiling. The floor has an electrically conductive coating to dissipate static electrical charges - Jet Propulsion Laboratory Edwards Facility, Mixer & Casting Building, Edwards Air Force Base, Boron, Kern County, CA

Energy gap opening by crossing drop cast single-layer graphene nanoribbons.

PubMed

Yamada, Toyo Kazu; Fukuda, Hideto; Fujiwara, Taizo; Liu, Polin; Nakamura, Kohji; Kasai, Seiya; Vazquez de Parga, Amadeo L; Tanaka, Hirofumi

2018-08-03

Band gap opening of a single-layer graphene nanoribbon (sGNR) sitting on another sGNR, fabricated by drop casting GNR solution on Au(111) substrate in air, was studied by means of scanning tunneling microscopy and spectroscopy in an ultra-high vacuum at 78 K and 300 K. GNRs with a width of ∼45 nm were prepared by unzipping double-walled carbon nanotubes (diameter ∼15 nm) using the ultrasonic method. In contrast to atomically-flat GNRs fabricated via the bottom-up process, the drop cast sGNRs were buckled on Au(111), i.e., some local points of the sGNR are in contact with the substrate (d ∼ 0.5 nm), but other parts float (d ∼ 1-3 nm), where d denotes the measured distance between the sGNR and the substrate. In spite of the fact that the nanoribbons were buckled, dI/dV maps confirmed that each buckled sGNR had a metallic character (∼3.5 G o ) with considerable uniform local density of states, comparable to a flat sGNR. However, when two sGNRs crossed each other, the crossed areas showed a band gap between -50 and +200 meV around the Fermi energy, i.e., the only upper sGNR electronic property changed from metallic to p-type semiconducting, which was not due to the bending, but the electronic interactions between the up and down sGNRs.

Grain refinement and texture development of cast bismuth-antimony alloy via severe plastic deformation

NASA Astrophysics Data System (ADS)

Im, Jae-Taek

The purpose of this work was to study learn about grain refinement mechanisms and texture development in cast n-type Bi90Sb10 alloy caused by severe plastic deformation. The practical objective is to produce a fine grained and textured microstructure in Bi90Sb10 alloy with enhanced thermoelectric performance and mechanical strength. In the study, twelve millimeter diameter cast bars of Bi90Sb 10 alloy were encapsulated in square cross section aluminum 6061 alloy containers. The composite bars were equal channel angular (ECAE) extruded through a 90 degree angle die at high homologous temperature. Various extrusion conditions were studied including punch speed (0.1, 0.3 and 0.6 in/min), extrusion temperature (220, 235 and 250°C), number of extrusion passes (1, 2 and 4), route (A, BC and C), and exit channel area reduction ratio (half and quarter area of inlet channel). The affect of an intermediate long term heat treatment (for 100 hours at 250°C under 10-3 torr vacuum) was explored. Processed materials were characterized by optical microscopy, x-ray diffraction, energy dispersive spectroscopy, wavelength dispersive spectroscopy and scanning electron microscopy. Texture was analyzed using the {006} reflection plane to identify the orientation of the basal poles in processed materials. The cast grains were irregularly shaped, had a grain size of hundreds-of-microns to millimeters, and showed inhomogeneous chemical composition. Severe plastic deformation refines the cast grains through dynamic recrystallization and causes the development of a bimodal microstructure consisting of fine grains (5-30 micron) and coarse grains (50-300 micron). ECAE processing of homogenizied Bi-Sb alloy causes grain refinement and produces a more uniform microstructure. Texture results show that ECAE route C processing gives a similar or slightly stronger texture than ECAE route A processing. In both cases, the basal-plane poles become aligned with the shear direction. Reduction area exit channel extrusion is more effective for both grain refinement and texture enhancement than simple ECAE processing.

Microstructurally tailored ceramics for advanced energy applications by thermoreversible gelcasting

NASA Astrophysics Data System (ADS)

Shanti, Noah Omar

Thermoreversible gelcasting (TRG) is an advantageous technique for rapidly producing bulk, net-shape ceramics and laminates. In this method, ceramic powder is suspended in warm acrylate triblock copolymer/alcohol solutions that reversibly gel upon cooling by the formation of endblock aggregates, to produce slurries which are cast into molds. Gel properties can be tailored by controlling the endblock and midblock lengths of the copolymer network-former and selecting an appropriate alcohol solvent. This research focuses on expanding and improving TRG techniques, focusing specifically on advanced energy applications including the solid oxide fuel cell (SOFC). Rapid drying of filled gels can lead to warping and cracking caused by high differential capillary stresses. A new drying technique using concentrated, alcohol-based solutions as liquid desiccants (LDs) to greatly reduce warping is introduced. The optimal LD is a poly(tert-butyl acrylate)/isopropyl alcohol solution with 5 mol% tert-butyl acrylate units. Alcohol emissions during drying are completely eliminated by combining initial drying in an LD with final stage drying in a vacuum oven having an in-line solvent trap. Porous ceramics are important structures for many applications, including SOFCs. Pore network geometries are tailored by the addition of fugitive fillers to TRG slurries. Uniform spherical, bimodal spherical and uniform fibrous fillers are used. Three-dimensional pore structures are visualized by X-ray computed tomography, allowing for direct measurements of physical parameters such as concentration and morphology as well as transport properties such as tortuosity. Tortuosity values as low as 1.52 are achieved when 60 vol% of solids are uniform spherical filler. Functionally graded laminates with layers ranging from 10 mum to > 1 mm thick are produced with a new technique that combines TRG with tape casting. Gels used for bulk casting are not suitable for use with tape casting, and appropriate base gels are selected for this technique. Each layer is cast in a single pass, and the layers are directly laminated. The anode support, anode functional layer, and electrolyte of anode-supported SOFCs are produced using this technique. The performance of SOFCs produced this way is not yet equal to that of traditionally processed cells, but shows the promise of this technique.

Near-Net-Shape Processing of Sintered Fibrous Ceramics Achieved

NASA Technical Reports Server (NTRS)

Angel, Paul W.

2000-01-01

A variety of sintered fibrous ceramic (SFC) materials have been developed over the last 50 years as thermal barrier materials for reentry applications. SFC materials typically exhibit very low thermal conductivities combined with low densities and good thermal stability up to 2500 F. These materials have flown successfully on the space shuttle orbiters since the 1960's. More recently, the McDonnell Douglas Corporation successfully used SFC tiles as a heat shield on the underside of its DC X test vehicle. For both of these applications, tiles are machined from blocks of a specific type of SFC called an alumina-enhanced thermal barrier (AETB). The sizes of these blocks have been limited by the manufacturing process. In addition, as much as 80 to 90 percent of the material can be lost during the machining of tiles with significant amounts of curvature. To address these problems, the NASA Glenn Research Center at Lewis Field entered a cooperative contract with the Boeing Company to develop a vacuum-assisted forming process that can produce large (approximately 4 square feet), severely contoured panels of AETB while saving costs in comparison to the conventional cast-and-machine billet process. For shuttle use, AETB is slurry cast, drained, and fired to form square billets conforming to the shape of the filtration box. The billets are then cut into tiles of the appropriate size for thermally protecting the space shuttle. Processing techniques have limited the maximum size of AETB billets to 21.5 square inches by 6.5-in. thick, but the space shuttles use discrete heat shield tiles no more than 8 to 12 square inches. However, in other applications, large, complex shapes are needed, and the tiling approach is undesirable. For such applications, vacuum-assisted forming can produce large parts with complex shapes while reducing machining waste and eliminating cemented joints between bonded billets. Because it allows contoured shapes to be formed, material utilization is inherently high. Initial estimates show that the amount of material lost during machining can be reduced by 50 percent or more. In addition, a fiber alignment favorable for minimum heat transfer is maintained for all panel shapes since the fibers are aligned parallel to the contoured surface of the forming tool or mold. The vacuum-assisted forming process can complete the entire forming operation in a matter of minutes and can produce multiple parts whose size is limited only by the size of the forming tool. To date, panels as large as 2 square feet have been demonstrated The vacuum-assisted forming process starts with the fabrication of a permeable forming tool, or mold, with the proper part contour. This reusable tool is mounted over an internal rib support structure, as depicted in the diagram, such that a vacuum can be pulled on the bottom portion of the tool. AETB slurry is then poured over and around the tool, liquid is drawn from the slurry, and the part forms over the tool surface. The part is then dried, fired, and finished machined. Future plans include an evaluation of the need for additional coatings and surface-toughness treatments to extend the durability and performance of this material.

Regolith thermal energy storage for lunar nighttime power

NASA Technical Reports Server (NTRS)

Tillotson, Brian

1992-01-01

A scheme for providing nighttime electric power to a lunar base is described. This scheme stores thermal energy in a pile of regolith. Any such scheme must somehow improve on the poor thermal conductivity of lunar regolith in vacuum. Two previous schemes accomplish this by casting or melting the regolith. The scheme described here wraps the regolith in a gas-tight bag and introduces a light gas to enhance thermal conductivity. This allows the system to be assembled with less energy and equipment than schemes which require melting of regolith. A point design based on the new scheme is presented. Its mass from Earth compares favorably with the mass of a regenerative fuel cell of equal capacity.

Method for forming consumable electrodes from metallic chip scraps

DOEpatents

Girshov, Vladimir Leonidovich; Podpalkin, Arcady Munjyvich; Treschevskiy, Arnold Nikolayevich; Abramov, Alexey Alexandrovich

2005-10-11

The method relates to metallurgical recycling of waste products, preferably titanium alloys chips scrap. Accordingly after crushing and cleaning, the chip scrap is subjected to vacuum-thermal degassing (VTD); the chip scrap is pressed into briquettes; the briquettes are placed into a mould allowing sufficient remaining space for the addition of molten metal alloy; the mould is pre-heated before filling with the molten metal alloy; the mould remaining space is filled with molten metal alloy. After cooling, the electrode is removed from the mould. The method provides a means for 100% use of chip scrap in producing consumable electrodes having increased mechanical strength and reduced interstitial impurities content leading to improved secondary cast alloys.

Evaluation of outgassing, tear strength, and detail reproduction in alginate substitute materials.

PubMed

Baxter, R T; Lawson, N C; Cakir, D; Beck, P; Ramp, L C; Burgess, J O

2012-01-01

To compare three alginate substitute materials to an alginate impression material for cast surface porosity (outgassing), tear strength, and detail reproduction. Detail reproduction tests were performed following American National Standards Institute/American Dental Association (ANSI/ADA) Specification No. 19. To measure tear strength, 12 samples of each material were made using a split mold, placed in a water bath until testing, and loaded in tension until failure at a rate of 500 mm/min using a universal testing machine. For cast surface porosity testing, five impressions of a Teflon mold with each material were placed in a water bath (37.8°C) for the in-mouth setting time and poured with vacuum-mixed Silky Rock die stone at 5, 10, 30, and 60 minutes from the start of mixing. The gypsum samples were analyzed with a digital microscope for surface porosity indicative of hydrogen gas release by comparing the surface obtained at each interval with four casts representing no, little, some, and significant porosity. Data analysis was performed using parametric and Kruskal-Wallis analysis of variance (ANOVA), Tukey/Kramer post-hoc tests (α=0.05), and individual Mann-Whitney U tests (α=0.0167). All alginate substitute materials passed the detail reproduction test. Tear strength of the alginate substitute materials was significantly better than alginate and formed three statistically different groups: AlgiNot had the lowest tear strength, Algin-X Ultra had the highest tear strength, and Position Penta Quick had intermediate tear strength. Significant variation in outgassing existed between materials and pouring times (p<0.05). All alginate substitute materials exhibited the least outgassing and cast porosity 60 minutes after mixing. Detail reproduction and tear strength of alginate substitute materials were superior to traditional alginate. The outgassing effect was minimal for most materials tested. Alginate substitute materials are superior replacements for irreversible hydrocolloid.

Letter Report Documenting Progress of Second Generation ATF FeCrAl Alloy Fabrication

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yamamoto, Y.; Yang, Y.; Field, K. G.

2014-06-10

Development of the 2nd generation ATF FeCrAl alloy has been initiated, and a candidate alloy was selected for trial tube fabrication through hot-extrusion and gun-drilling processes. Four alloys based on Fe-13Cr-4.5Al-0.15Y in weight percent were newly cast with minor alloying additions of Mo, Si, Nb, and C to promote solid-solution and second-phase precipitate strengthening. The alloy compositions were selected with guidance from computational thermodynamic tools. The lab-scale heats of ~ 600g were arc-melted and drop-cast, homogenized, hot-forged and -rolled, and then annealed producing plate shape samples. An alloy with Mo and Nb additions (C35MN) processed at 800°C exhibits very finemore » sub-grain structure with the sub-grain size of 1-3μm which exhibited more than 25% better yield and tensile strengths together with decent ductility compared to the other FeCrAl alloys at room temperature. It was found that the Nb addition was key to improving thermal stability of the fine sub-grain structure. Optimally, grains of less than 30 microns are desired, with grains up to and order of magnitude in desired produced through Nb addition. Scale-up effort of the C35MN alloy was made in collaboration with a commercial cast company who has a capability of vacuum induction melting. A 39lb columnar ingot with ~81mm diameter and ~305mm height (with hot-top) was commercially cast, homogenized, hot-extruded, and annealed providing 10mm-diameter bar-shape samples with the fine sub-grain structure. This commercial heat proved consistent with materials produced at ORNL at the lab-scale. Tubes and end caps were machined from the bar sample and provided to another work package for the ATF-1 irradiation campaign in the milestone M3FT-14OR0202251.« less

Transparent layered YAG ceramics with structured Yb doping produced via tape casting

NASA Astrophysics Data System (ADS)

Hostaša, Jan; Piancastelli, Andreana; Toci, Guido; Vannini, Matteo; Biasini, Valentina

2017-03-01

The flexibility of the ceramic production process, in particular in terms of shaping and spatial control of distribution of active ions, is one of the strong points in favor of transparent ceramics. In high power lasers in particular, where thermal management is a critical issue, the finely controlled design of spatial distribution of the doping ions within the laser gain media can reduce undesired thermally induced effects and large temperature gradients, and thus enhance the efficiency and laser beam quality especially under increased thermal load. In the present work transparent structured YAG ceramics with Yb doping were produced by tape casting followed by thermal compression of assembled tapes and sintered under high vacuum. The thermal compression of variously doped tape cast layers is a very promising method because it allows a high precision and good control over dopant distribution in the sintered material. After sintering, the distribution of Yb across the layers was characterized by SEM-EDX and the thickness of Yb diffusion zones between the layers with different Yb content was measured. Optical homogeneity was assessed by means of optical transmittance mapping of the samples and by 2D scanning of laser output. The effect of structured dopant distribution on laser performance was measured in quasi-CW and CW regime with different duty factors. Slope efficiency values higher than 50% were measured both in quasi-CW and in CW lasing conditions. The results are in good agreement with previously calculated predictions, confirming the beneficial effect of structured doping on laser performances and enlightening the impact of the residual scattering losses. Compared to other processing methods, such as the pressing of granulated powders, tape casting followed by thermal compression leads to straight and narrow interfaces between layers with different composition and allows to build structures composed of extremely thin layers with defined dopant content.

Materials Selection and Their Characteristics as Used in Rapid Prototyping

NASA Technical Reports Server (NTRS)

Cooper, K.; Salvail, P.; Vesely, E.; Wells, D.

1999-01-01

NASA's Marshall Space Flight Center (MSFC) conducted a program to evaluate six technologies used in Rapid Prototyping (RP) to produce investment casting patterns. In this paper, RP refers to the collective additive fabrication technologies known as Solid Free-Form Fabrication. Such technologies are being used with increasing frequency in manufacturing applications, due in part to their rapidly expanding capabilities to fabricate models from many types of materials. This study used ABS plastic, polycarbonate, TrueForm PM6, epoxy resin, paper, starch, and wax. The baseline model was a semi-complex prototype fuel pump housing, intended for use in the X-33 reusable launch vehicle. All models were shelled in a production- grade colloidal silica ceramic. Primary coats were zircon-base flour with zircon backup, while secondary coats were silica grains with a tabular alumina backup. Each model was shelled in an identical manner, using the same atmospheric conditions and drying times, as well as the same number of layers. Bake-outs and firing cycles were consistent with the leach ability of each material. Preheat and bath temperatures were also kept consistent. All molds were cast in vacuum using a hydrogen-resistant superalloy (NASA- 23) that was developed in-house. The final technical evaluation included detailed measurements of the model and the final casting, in order to determine any dimensional changes caused by different pattern materials, as well as documentation of all defects and any obvious refractory/model reactions. Prototype production costs were estimated for each method and taken into consideration during trade-off analysis.

Pseudoplasticity of Propellant Slurry with Varied Aluminium Content for Castability Development

NASA Astrophysics Data System (ADS)

Restasari, A.; Budi, R. S.; Hartaya, K.

2018-04-01

The modification of the percentage of aluminium is necessary to obtain certain specific impulse. But, it affects the pseudoplasticity of propellant in elapsed time that is important in casting. Therefore, this research attempts to investigate the pseudoplasticity of propellant slurry with varied aluminium contents and as time elapsed, the range of percentage of aluminium and time that allows propellant slurry to be well processed. The methods include measuring the viscosity of propellant slurries that contain 6, 8, 10, 12, 14, 16 and 18% of aluminium at varied shear rates until 40 minutes after mixing by using Brookfield viscometer. The graphs of viscosity versus shear rate were made to determine pseudoplasticity index. After that, the graph volume fraction versus pseudoplasticity index were made to be investigated. It is concluded that the more aluminium contents, the slurries with 6 to 12% aluminium contents exhibit more pseudoplastic behaviour, but the slurries with 12 to 16% aluminium exhibit less pseudoplastic. While, slurry of 18% aluminium exhibit high pseudoplasticity. In the correlation with the time, the slurry compositions of 6, 8, 14, 16% aluminium become more pseudoplastic as time elapsed. While, for compositions of 10, 12 and 18% aluminium, the trend becomes contrary. Based on the pseudoplasticity index, propellant slurries that contain 10 and 14% of aluminium are suitable for pressure casting. While for slurries with 6, 8 and 16% of aluminium are also suitable for vacuum casting. All of those suitability are possesed until 40 minutes after mixing. While, the composition of slurries that contain 12 and 18% of aluminium need to be modified to enhanced its castability.

Fibrillar structure and elasticity of hydrating collagen: a quantitative multiscale approach.

PubMed

Morin, Claire; Hellmich, Christian; Henits, Peter

2013-01-21

It is well known that hydration of collagenous tissues leads to their swelling, as well as to softening of their elastic behavior. However, it is much less clear which microstructural and micromechanical "rules" are involved in this process. Here, we develop a theoretical approach cast in analytical mathematical formulations, which is experimentally validated by a wealth of independent tests on collagenous tissues, such as X-ray diffraction, vacuum drying, mass measurements, and Brillouin light scattering. The overall emerging picture is the following: air-drying leaves water only in the gap zones between the triple-helical collagen molecules; upon re-hydration, the extrafibrillar space is established at volumes directly proportional to the hydration-induced swelling of the (micro) fibrils, until the maximum equatorial distance between the long collagen molecules is reached. Thereafter, the volume of the fibrils stays constant, and only the extrafibrillar volume continues to grow. At all these hydration stages, the elastic behavior is governed by the same, hydration-invariant mechanical interaction pattern of only two, interpenetrating mechanical phases: transversely isotropic molecular collagen and isotropic water (or empty pores in the vacuum-dried case). Copyright © 2012 Elsevier Ltd. All rights reserved.

Double Higgs mechanisms, supermassive stable particles and the vacuum energy

NASA Astrophysics Data System (ADS)

Santillán, Osvaldo P.; Gabbanelli, Luciano

2016-07-01

In the present work, a hidden scenario which cast a long-lived superheavy particle A0 and simultaneously an extremely light particle a with mass ma ˜ 10-32-10-33 eV is presented. The potential energy V (a) of the particle a models the vacuum energy density of the universe ρc ≃ 10-47GeV4. On the other hand, the A0 particle may act as superheavy dark matter at present times and the products of its decay may be observed in high energy cosmic ray events. The hidden sector proposed here include light fermions with masses near the neutrino mass mν ˜ 10-2 eV and superheavy ones with masses of the order of the GUT scale, interacting through a hidden SU(2)L interaction which also affects the ordinary sector. The construction of such combined scenario is nontrivial since the presence of light particles may spoil the stability of the heavy particle A0. However, double Higgs mechanisms may be helpful for overcoming this problem. In this context, the stability of the superheavy particle A0 is ensured due to chiral symmetry arguments elaborated in the text.

Investigation of Test Methods, Material Properties and Processes for Solar Cell Encapsulants

NASA Technical Reports Server (NTRS)

Willis, P.; Baum, B.

1982-01-01

The evaluation of potentially useful low cost encapsulation materials is discussed. The goal is to identify, evaluate, test and recommend encapsulant materials and processes for the production of cost effective, long life solar cell modules. Technical investigations concerned the development of advanced cure chemistries for lamination type pottants; the continued evaluation of soil resistant surface treatment, and the results of an accelerated aging test program for the comparison of material stabilities. New compounds were evaluated for efficiency in curing both ethylene/vinyl acetate and ethylene/methyl acrylate pottants intended for vacuum bag lamination of solar cells. Two component aliphatic urethane casting syrups were evaluated for suitability as solar module pottants on the basis of optical, physical and fabrication characteristics.

Evidencing `Tight Bound States' in the Hydrogen Atom:. Empirical Manipulation of Large-Scale XD in Violation of QED

NASA Astrophysics Data System (ADS)

Amoroso, Richard L.; Vigier, Jean-Pierre

2013-09-01

In this work we extend Vigier's recent theory of `tight bound state' (TBS) physics and propose empirical protocols to test not only for their putative existence, but also that their existence if demonstrated provides the 1st empirical evidence of string theory because it occurs in the context of large-scale extra dimensionality (LSXD) cast in a unique M-Theoretic vacuum corresponding to the new Holographic Anthropic Multiverse (HAM) cosmological paradigm. Physicists generally consider spacetime as a stochastic foam containing a zero-point field (ZPF) from which virtual particles restricted by the quantum uncertainty principle (to the Planck time) wink in and out of existence. According to the extended de Broglie-Bohm-Vigier causal stochastic interpretation of quantum theory spacetime and the matter embedded within it is created annihilated and recreated as a virtual locus of reality with a continuous quantum evolution (de Broglie matter waves) governed by a pilot wave - a `super quantum potential' extended in HAM cosmology to be synonymous with the a `force of coherence' inherent in the Unified Field, UF. We consider this backcloth to be a covariant polarized vacuum of the (generally ignored by contemporary physicists) Dirac type. We discuss open questions of the physics of point particles (fermionic nilpotent singularities). We propose a new set of experiments to test for TBS in a Dirac covariant polarized vacuum LSXD hyperspace suggestive of a recently tested special case of the Lorentz Transformation put forth by Kowalski and Vigier. These protocols reach far beyond the recent battery of atomic spectral violations of QED performed through NIST.

Thermal expansion and microstructural analysis of experimental metal-ceramic titanium alloys.

PubMed

Zinelis, Spiros; Tsetsekou, Athena; Papadopoulos, Triantafillos

2003-10-01

Statement of problem Low-fusing porcelains for titanium veneering have demonstrated inferior color stability and metal-ceramic longevity compared to conventional porcelains. This study evaluated the microstructure and thermal expansion coefficients of some experimental titanium alloys as alternative metallic substrates for low-fusing conventional porcelain. Commercially pure titanium (CP Ti) and various metallic elements (Al, Co, Sn, Ga, In, Mn) were used to prepare 8 titanium alloys using a commercial 2-chamber electric-arc vacuum/inert gas dental casting machine (Cyclarc). The nominal compositions of these alloys were the following (wt%): I: 80Ti-18Sn-1.5In-0.5Mn; II: 76Ti-12Ga-7Sn-4Al-1Co; III: 87Ti-13Ga; IV: 79Ti-13Ga-7Al-1Co; V: 82Ti-18In; VI: 75.5Ti-18In-5Al-1Co-0.5Mn; VII: 85Ti-10Sn-5Al; VIII: 78Ti-12Co-7Ga-3Sn. Six rectangular wax patterns for each test material (l = 25 mm, w = 3 mm, h = 1 mm) were invested with magnesia-based material and cast with grade II CP Ti (control) and the 8 experimental alloys. The porosity of each casting was evaluated radiographically, and defective specimens were discarded. Two cast specimens from CP Ti and alloys I-VIII were embedded in epoxy resin and, after metallographic grinding and polishing, were studied by means of scanning electron microscopy and wavelength dispersive electron probe microanalysis. One specimen of each material was utilized for the determination of coefficient of thermal expansion (CTE) with a dilatometer operating from room temperature up to 650 degrees C at a heating rate of 5 degrees C/minute. Secondary electron images (SEI) and compositional backscattered electron images (BEI-COMPO) revealed that all cast specimens consisted of a homogeneous matrix except Alloy VIII, which contained a second phase (possibly Ti(2)Co) along with the titanium matrix. The results showed that the coefficient of thermal expansion (CTE) varied from 10.1 to 13.1 x 10(-6)/ degrees C (25 degrees -500 degrees C), depending on the elemental composition. The CTE of titanium can be considerably changed by alloying. Two-phase alloys were developed when alloying elements were added in concentrations greater than the maximum solubility limit in alpha-titanium phase.

Properties of TiNi intermetallic compound industrially produced by combustion synthesis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kaieda, Yoshinari

Most TiNi shape memory intermetallic compounds are conventionally produced by the process including high frequency induction vacuum melting and casting. A gravity segregation occurs in a cast TiNi ingot because of the big difference in the specific gravity between Ti and Ni. It is difficult to control accurately the phase transformation temperature of TiNi shape memory intermetallic compound produced by the conventional process, because the martensitic transformation temperature shifts by 10K due to the change in 0.1 % of Ni content. Homogeneous TiNi intermetallic compound is produced by the industrial process including combustion synthesis method, which is a newly developedmore » manufacturing process. In the new process, phase transformation temperatures of TiNi can be controlled accurately by controlling the ratio of Ti and Ni elemental starting powders. The chemical component, the impurities and the phase transformation temperatures of the TiNi products industrially produced by the process are revealed. These properties are vitally important when combustion synthesis method is applied to an industrial mass production process for producing TiNi shape memory intermetallic compounds. TiNi shape memory products are industrially and commercially produced today the industrial process including combustion synthesis. The total production weight in a year is 30 tins in 1994.« less

Tribo-mechanical properties of thin boron coatings deposited on polished cobalt alloy surfaces for orthopedic applications

PubMed Central

Klepper, C. C.; Williams, J. M.; Truhan, J.J.; Qu, J.; Riester, L.; Hazelton, R. C.; Moschella, J.J.; Blau, P.J.; Anderson, J.P.; Popoola, O.O.; Keitz, M.D.

2008-01-01

This paper presents experimental evidence that thin (<∼200 nm) boron coatings, deposited with a (vacuum) cathodic arc technique on pre-polished Co-Cr-Mo surfaces, could potentially extend the life of metal-on-polymer orthopedic devices using cast Co-Cr-Mo alloy for the metal component. The primary tribological test used a linear, reciprocating pin-on-disc arrangement, with pins made of ultra-high molecular weight polyethylene. The disks were cast Co-Cr-Mo samples that were metallographically polished and then coated with boron at a substrate bias of 500 V and at about 100 °C. The wear tests were carried out in a saline solution to simulate the biological environment. The improvements were manifested by the absence of a detectable wear track scar on the coated metal component, while significant polymer transfer film was detected on the uncoated (control) samples tested under the same conditions. The polymer transfer track was characterized with both profilometry and Rutherford Backscattering Spectroscopy. Mechanical characterization of the thin films included nano-indentation, as well as additional pin-on-disk tests with a steel ball to demonstrate adhesion, using ultra-high frequency acoustic microscopy to probe for any void occurrence at the coating-substrate interface. PMID:19340285

Synthesize and microstructure characterization of Ni{sub 43}Mn{sub 41}Co{sub 5}Sn{sub 11} Heusler alloy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elwindari, Nastiti; Manaf, Azwar, E-mail: azwar@ui.ac.id

2016-06-17

The ferromagnetic heusler alloys are promising materials in many technical applications due to their multifunctional properties such as shape memory effect, magnetocaloric effect, giant magnetoresistance, etc. In this work, synthesize and characterization of polycrystalline Ni{sub 43}Mn{sub 41}Co{sub 5}Sn{sub 11} (NMCS) alloy are reported. Alloy preparation was conducted by melting the constitute elements under an innert Argon (Ar) atmosphere in a vacuum mini arc-melting furnace. Homogenization of the microstructure of the as-cast ingot was obtained after annealing process at 750°C for 48 hours. It is shown that the dendrites structure has changed to equaixed grains morphology after homogenization. Microstructure characteristics ofmore » material by x-ray diffraction revealed that the alloy has a L{sub 21}-type cubic crystal structure as the main phase at room temperature. In order to induce the shape anisotropy, a forging treatment was applied to show the shape orientation of material. Various enhancements of magnetic properties in a longitudinal direction were observed at various degree of anisotropy. The microstructure changes of as-cast NMCS and effects of homogenization treatments as studied by scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) are discussed in details.« less

Scalable creation of gold nanostructures on high performance engineering polymeric substrate

NASA Astrophysics Data System (ADS)

Jia, Kun; Wang, Pan; Wei, Shiliang; Huang, Yumin; Liu, Xiaobo

2017-12-01

The article reveals a facile protocol for scalable production of gold nanostructures on a high performance engineering thermoplastic substrate made of polyarylene ether nitrile (PEN) for the first time. Firstly, gold thin films with different thicknesses of 2 nm, 4 nm and 6 nm were evaporated on a spin-coated PEN substrate on glass slide in vacuum. Next, the as-evaporated samples were thermally annealed around the glass transition temperature of the PEN substrate, on which gold nanostructures with island-like morphology were created. Moreover, it was found that the initial gold evaporation thickness and annealing atmosphere played an important role in determining the morphology and plasmonic properties of the formulated Au NPs. Interestingly, we discovered that isotropic Au NPs can be easily fabricated on the freestanding PEN substrate, which was fabricated by a cost-effective polymer solution casting method. More specifically, monodispersed Au nanospheres with an average size of ∼60 nm were obtained after annealing a 4 nm gold film covered PEN casting substrate at 220 °C for 2 h in oxygen. Therefore, the scalable production of Au NPs with controlled morphology on PEN substrate would open the way for development of robust flexible nanosensors and optical devices using high performance engineering polyarylene ethers.

Enhancing fire safety at Hydro plants with dry transformers

DOE Office of Scientific and Technical Information (OSTI.GOV)

Clemen, D.M.

Hydroelectric plant owners and engineers can use dry-type transformers to reduce fire hazards in auxiliary power systems. The decision to replace a liquid-immersed transformer with a dry-type product has a price: higher unit cost and a need to be more vigilant in detailing transformer specifications. But, whether the change affects only one failed transformer or is part of a plant rehabilitation project, the benefits in safety can be worth it. Voltages on hydroelectric plant auxiliary power systems can range from a 20 kV medium-voltage system to the normal 480-208/120 V low-voltage system. Dry transformers typically are used in such systemsmore » to reduce the fire hazard present with liquid-filled transformers. For a hydro plant owner or engineer seeking alternatives to liquid-filled transformers, there are two main kinds of dry-type transformers to consider: vacuum pressure impregnated (VPI) and cast coil epoxy resin. VPI transformers normally are manufactured in sizes up to 6,000 kVA with primary voltage ratings up to 20 kV. Cast coil transformers can be made in sizes from 75 to 10,000 kVA, with primary voltage ratings up to 34,500 V. Although the same transformer theory applies to dry transformers as to liquid-filled units, the cooling medium, air, required different temperature rise ratings, dielectric tests, and construction techniques to ensure reliability. Consequently, the factory and field tests for dry units are established by a separate set of American National Standards Institute (ANSI)/Institute of Electrical and Electronics Engineers (IEEE) standards. Cast coil transformers have several important advantages over VPI units.« less

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leung, Bonnie; Hitchcock, Adam; Brash, John

Spun-cast films of polystyrene (PS) blended with polylactide (PLA) were visualized and characterized using atomic force microscopy (AFM) and synchrotron-based X-ray photoemission electron microscopy (X-PEEM). The composition of the two polymers in these systems was determined by quantitative chemical analysis of near-edge X-ray absorption signals recorded with X-PEEM. The surface morphology depends on the ratio of the two components, the total polymer concentration, and the temperature of vacuum annealing. For most of the blends examined, PS is the continuous phase with PLA existing in discrete domains or segregated to the air?polymer interface. Phase segregation was improved with further annealing. Amore » phase inversion occurred when films of a 40:60 PS:PLA blend (0.7 wt percent loading) were annealed above the glass transition temperature (Tg) of PLA.« less

The Colloquium

NASA Astrophysics Data System (ADS)

Amoroso, Richard L.

HÉCTOR A.A brief introductory survey of Unified Field Mechanics (UFM) is given from the perspective of a Holographic Anthropic Multiverse cosmology in 12 `continuous-state' dimensions. The paradigm with many new parameters is cast in a scale-invariant conformal covariant Dirac polarized vacuum utilizing extended HD forms of the de Broglie-Bohm and Cramer interpretations of quantum theory. The model utilizes a unique form of M-Theory based in part on the original hadronic form of string theory that had a variable string tension, TS and included a tachyon. The model is experimentally testable, thus putatively able to demonstrate the existence of large-scale additional dimensionality (LSXD), test for QED violating tight-bound state spectral lines in hydrogen `below' the lowest Bohr orbit, and surmount the quantum uncertainty principle utilizing a hyperincursive Sagnac Effect resonance hierarchy.

Encapsulation of ZnO particles by metal fluorides: Towards an application as transparent insulating coatings for windows

NASA Astrophysics Data System (ADS)

Trenque, Isabelle; Mornet, Stéphane; Duguet, Etienne; Majimel, Jérôme; Brüll, Annelise; Teinz, Katharina; Kemnitz, Erhard; Gaudon, Manuel

2013-01-01

Because ZnO is a promising candidate for getting efficient films or varnishes with thermal insulating abilities for windows applications, the effect of the encapsulation of ZnO particles in shells of low refractive index material on the improvement of the visible light transmission was investigated. ZnO-MgF2 core-shell particles were synthesized by deposition of fluoride sols on ZnO particles through a vacuum slip casting process like. The transmission behaviours were first indirectly studied by diffuse reflexion measurements on powder beds. Then, particle films were elaborated by a screen printing process which ensured direct transmission measurements. The encapsulation of ZnO particles with a coating shell of 1.3 wt.% of MgF2 improves the visible light transmission of 32%.

Effects of substitution of Mo for Nb on less-common properties of Finemet alloys

NASA Astrophysics Data System (ADS)

Butvin, P.; Butvinová, B.; Silveyra, J. M.; Chromčíková, M.; Janičkovič, D.; Sitek, J.; Švec, P.; Vlasák, G.

2010-10-01

Particular properties of Fe-Nb/Mo-Cu-B-Si rapidly quenched ribbons were examined. Apart from minor variation, no significant difference due to the Mo for Nb substitution was observed in alloy density and its annealing-induced changes. The same holds for the anisotropic thermal expansion of as-cast ribbon when annealed and for induced anisotropy when annealed under stress. The Mo-substituted ribbons show only slightly higher crystallinity and lower coercivity if annealed in inert gas ambience than in vacuum. Some diversity in surface to interior heterogeneity of the differently annealed ribbons can still be distinguished. Preserving a minor percentage of Nb together with Mo does not seem substantiated to obtain favorable soft magnetic properties of ribbons annealed in inert gas.

Pneumatically Actuated Miniature Peristaltic Vacuum Pumps

NASA Technical Reports Server (NTRS)

Feldman, Sabrina; Feldman, Jason; Svehla, Danielle

2003-01-01

Pneumatically actuated miniature peristaltic vacuum pumps have been proposed for incorporation into advanced miniature versions of scientific instruments that depend on vacuum for proper operation. These pumps are expected to be capable of reaching vacuum-side pressures in the torr to millitorr range (from .133 down to .0.13 Pa). Vacuum pumps that operate in this range are often denoted roughing pumps. In comparison with previously available roughing pumps, these pumps are expected to be an order of magnitude less massive and less power-hungry. In addition, they would be extremely robust, and would operate with little or no maintenance and without need for oil or other lubricants. Portable mass spectrometers are typical examples of instruments that could incorporate the proposed pumps. In addition, the proposed pumps could be used as roughing pumps in general laboratory applications in which low pumping rates could be tolerated. The proposed pumps could be designed and fabricated in conventionally machined and micromachined versions. A typical micromachined version (see figure) would include a rigid glass, metal, or plastic substrate and two layers of silicone rubber. The bottom silicone layer would contain shallow pump channels covered by silicone arches that could be pushed down pneumatically to block the channels. The bottom silicone layer would be covered with a thin layer of material with very low gas permeability, and would be bonded to the substrate everywhere except in the channel areas. The top silicone layer would be attached to the bottom silicone layer and would contain pneumatic- actuation channels that would lie crosswise to the pump channels. This version is said to be micromachined because the two silicone layers containing the channels would be fabricated by casting silicone rubber on micromachined silicon molds. The pneumatic-actuation channels would be alternately connected to a compressed gas and (depending on pump design) either to atmospheric pressure or to a partial vacuum source. The design would be such that the higher pneumatic pressure would be sufficient to push the silicone arches down onto the substrates, blocking the channels. Thus, by connecting pneumatic- actuation channels to the two pneumatic sources in spatial and temporal alternation, waves of opening and closing, equivalent to peristalsis, could be made to move along the pump channels. A pump according to this concept could be manufactured inexpensively. Pneumatic sources (compressors and partial vacuum sources) similar those needed for actuation are commercially available; they typically have masses of .100 g and power demands of the order of several W. In a design-optimization effort, it should be possible to reduce masses and power demands below even these low levels and to integrate pneumatic sources along with the proposed pumps into miniature units with overall dimensions of no more than a few centimeters per side.

New solar axion search using the CERN Axion Solar Telescope with 4He filling

NASA Astrophysics Data System (ADS)

Arik, M.; Aune, S.; Barth, K.; Belov, A.; Bräuninger, H.; Bremer, J.; Burwitz, V.; Cantatore, G.; Carmona, J. M.; Cetin, S. A.; Collar, J. I.; Da Riva, E.; Dafni, T.; Davenport, M.; Dermenev, A.; Eleftheriadis, C.; Elias, N.; Fanourakis, G.; Ferrer-Ribas, E.; Galán, J.; García, J. A.; Gardikiotis, A.; Garza, J. G.; Gazis, E. N.; Geralis, T.; Georgiopoulou, E.; Giomataris, I.; Gninenko, S.; Gómez Marzoa, M.; Hasinoff, M. D.; Hoffmann, D. H. H.; Iguaz, F. J.; Irastorza, I. G.; Jacoby, J.; Jakovčić, K.; Karuza, M.; Kavuk, M.; Krčmar, M.; Kuster, M.; Lakić, B.; Laurent, J. M.; Liolios, A.; Ljubičić, A.; Luzón, G.; Neff, S.; Niinikoski, T.; Nordt, A.; Ortega, I.; Papaevangelou, T.; Pivovaroff, M. J.; Raffelt, G.; Rodríguez, A.; Rosu, M.; Ruz, J.; Savvidis, I.; Shilon, I.; Solanki, S. K.; Stewart, L.; Tomás, A.; Vafeiadis, T.; Villar, J.; Vogel, J. K.; Yildiz, S. C.; Zioutas, K.; CAST Collaboration

2015-07-01

The CERN Axion Solar Telescope (CAST) searches for a →γ conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward the Sun. Two parallel magnet bores can be filled with helium of adjustable pressure to match the x-ray refractive mass mγ to the axion search mass ma. After the vacuum phase (2003-2004), which is optimal for ma≲0.02 eV , we used 4He in 2005-2007 to cover the mass range of 0.02-0.39 eV and 3He in 2009-2011 to scan from 0.39 to 1.17 eV. After improving the detectors and shielding, we returned to 4He in 2012 to investigate a narrow ma range around 0.2 eV ("candidate setting" of our earlier search) and 0.39-0.42 eV, the upper axion mass range reachable with 4He, to "cross the axion line" for the KSVZ model. We have improved the limit on the axion-photon coupling to ga γ<1.47 ×10-10 GeV-1 (95% C.L.), depending on the pressure settings. Since 2013, we have returned to the vacuum and aim for a significant increase in sensitivity.

Northwestern University Flexible Subischial Vacuum Socket for persons with transfemoral amputation-Part 1: Description of technique.

PubMed

Fatone, Stefania; Caldwell, Ryan

2017-06-01

Current transfemoral prosthetic sockets restrict function, lack comfort, and cause residual limb problems. Lower proximal trim lines are an appealing way to address this problem. Development of a more comfortable and possibly functional subischial socket may contribute to improving quality of life of persons with transfemoral amputation. The purpose of this study was to (1) describe the design and fabrication of a new subischial socket and (2) describe efforts to teach this technique. Development project. Socket development involved defining the following: subject and liner selection, residual limb evaluation, casting, positive mold rectification, check socket fitting, definitive socket fabrication, and troubleshooting of socket fit. Three hands-on workshops to teach the socket were piloted and attended by 30 certified prosthetists and their patient models. Patient models responded positively to the comfort, range of motion, and stability of the new socket while prosthetists described the technique as "straight forward, reproducible." To our knowledge, this is the first attempt to create a teachable subischial socket, and while it appears promising, more definitive evaluation is needed. Clinical relevance We developed the Northwestern University Flexible Subischial Vacuum (NU-FlexSIV) Socket as a more comfortable alternative to current transfemoral sockets and demonstrated that it could be taught successfully to prosthetists.

Studies of Lubricating Materials in Vacuum

NASA Technical Reports Server (NTRS)

Buckley, D. H.; Johnson, R. L.; Swikert, M. A.

1964-01-01

Lubricating materials for use in a vacuum environment have been the subject of a series of experimental investigations. Evaporation properties were evaluated for solid polymeric compositions. Friction and wear studies explored the behavior during sliding contact for series of polymeric compositions, binary alloys containing soft film-forming phases, complex alloys with film-forming materials, and a burnished MoS2 film. Friction and wear experiments were conducted at 10(exp-9)mm Hg with a 3/16-inch-radius-hemisphere rider specimen sliding on the flat surface of a rotating 2-1/2-inch-diameter disk specimen with materials that had low rates of evaporation. The influence of fillers in polytetrafluoroethylene (PTFE) on decomposition during vacuum friction studies was determined with a mass spectrometer. A real advantage in reducing decomposition and improving friction wear properties is gained by adding fillers (e.g., copper) that improve thermal conductivity through the composite materials. A polyimide and an epoxy-MoS2 composition material were found to have better friction and wear properties than PTFE compositions. A series of alloys (cast binary as well as more complex alloys) that contained microinclusions of potential film-forming material was studied. These materials replaced the normal surface oxides as they were worn away on sliding contact. Iron sulfide, nickel oxide, and tin are typical film-forming materials employed and were demonstrated to be effective in inhibiting surface welding and reducing friction. A burnished MoS2 film applied to type 440-C stainless steel in argon with a rotating soft wire brush had good endurance properties but somewhat higher friction than commercially available bonded films. An oil film applied to the burnished MoS2 markedly reduced its endurance life.

Indigenous lunar construction materials

NASA Technical Reports Server (NTRS)

Rogers, Wayne P.; Sture, Stein

1991-01-01

The utilization of local resources for the construction and operation of a lunar base can significantly reduce the cost of transporting materials and supplies from Earth. The feasibility of processing lunar regolith to form construction materials and structural components is investigated. A preliminary review of potential processing methods such as sintering, hot-pressing, liquification, and cast basalt techniques, was completed. The processing method proposed is a variation on the cast basalt technique. It involves liquification of the regolith at 1200-1300 C, casting the liquid into a form, and controlled cooling. While the process temperature is higher than that for sintering or hot-pressing (1000-1100 C), this method is expected to yield a true engineering material with low variability in properties, high strength, and the potential to form large structural components. A scenario for this processing method was integrated with a design for a representative lunar base structure and potential construction techniques. The lunar shelter design is for a modular, segmented, pressurized, hemispherical dome which could serve as habitation and laboratory space. Based on this design, estimates of requirements for power, processing equipment, and construction equipment were made. This proposed combination of material processing method, structural design, and support requirements will help to establish the feasibility of lunar base construction using indigenous materials. Future work will refine the steps of the processing method. Specific areas where more information is needed are: furnace characteristics in vacuum; heat transfer during liquification; viscosity, pouring and forming behavior of molten regolith; design of high temperature forms; heat transfer during cooling; recrystallization of basalt; and refinement of estimates of elastic moduli, compressive and tensile strength, thermal expansion coefficient, thermal conductivity, and heat capacity. The preliminary design of the lunar shelter showed us that joining is a critical technology needed for building a structure from large segments. The problem of joining is important to the design of any structure that is not completely prefabricated. It is especially important when the structure is subjected to tensile loading by an internal pressure. For a lunar shelter constructed from large segments the joints between these large segments must be strong, and they must permit automated construction. With a cast basalt building material which is brittle, there is the additional problem of connecting the joint with the material and avoiding stress concentration that would cause failure. Thus, a well-defined project which we intend to pursue during this coming year is the design of joints for cast basalt structural elements.

Scanning electron microscopy of bone.

PubMed

Boyde, Alan

2012-01-01

This chapter described methods for Scanning Electron Microscopical imaging of bone and bone cells. Backscattered electron (BSE) imaging is by far the most useful in the bone field, followed by secondary electrons (SE) and the energy dispersive X-ray (EDX) analytical modes. This chapter considers preparing and imaging samples of unembedded bone having 3D detail in a 3D surface, topography-free, polished or micromilled, resin-embedded block surfaces, and resin casts of space in bone matrix. The chapter considers methods for fixation, drying, looking at undersides of bone cells, and coating. Maceration with alkaline bacterial pronase, hypochlorite, hydrogen peroxide, and sodium or potassium hydroxide to remove cells and unmineralised matrix is described in detail. Attention is given especially to methods for 3D BSE SEM imaging of bone samples and recommendations for the types of resin embedding of bone for BSE imaging are given. Correlated confocal and SEM imaging of PMMA-embedded bone requires the use of glycerol to coverslip. Cathodoluminescence (CL) mode SEM imaging is an alternative for visualising fluorescent mineralising front labels such as calcein and tetracyclines. Making spatial casts from PMMA or other resin embedded samples is an important use of this material. Correlation with other imaging means, including microradiography and microtomography is important. Shipping wet bone samples between labs is best done in glycerol. Environmental SEM (ESEM, controlled vacuum mode) is valuable in eliminating -"charging" problems which are common with complex, cancellous bone samples.

Charpy Impact Energy and Microindentation Hardness of 60-NITINOL

NASA Technical Reports Server (NTRS)

Stanford, Malcolm K.

2012-01-01

60-NITINOL (60 wt.% Ni 40 wt.% Ti) is being studied as a material for advanced aerospace components. The Charpy impact energy and microindentation hardness has been studied for this material, fabricated by vacuum induction skull melting (casting) and by hot isostatic pressing. Test specimens were prepared in various hardened and annealed heat treatment conditions. The average impact energy ranged from 0.33 to 0.49J for the hardened specimens while the annealed specimens had impact energies ranging from 0.89 to 1.18J. The average hardness values of the hardened specimens ranged from 590 to 676 HV while that of the annealed specimens ranged from 298 to 366 HV, suggesting an inverse relationship between impact energy and hardness. These results are expected to provide guidance in the selection of heat treatment processes for the design of mechanical components.

Characterization of structure and thermophysical properties of three ESR slags

NASA Astrophysics Data System (ADS)

Plotkowski, A.; deBarbadillo, J.; Krane, Matthew J. M.

2016-07-01

The structure and properties of electroslag remelting (ESR) slags were characterized. Slags samples of three compositions were obtained from industrial remelting processes at Special Metals Corporation and from casting in a laboratory vacuum induction melter. The structure of the slag samples was observed using optical and electron microscopy, and phases were identified and their relative amounts quantified using X-ray diffraction. Laser flash thermal diffusivity, density, and differential scanning calorimetry measurements for specific heat were performed to determine the bulk thermal conductivity of the samples. Sample porosity was measured as a function of depth using a serial sectioning technique, and a onedimensional computational model was developed to estimate the thermal conductivity of the fully dense slags. These results are discussed in context with previous studies, and opportunities for future research are identified. AFRL Case Number: 88ABW-2015-1871.

Organic nanofibers from squarylium dyes: local morphology, optical, and electrical properties

NASA Astrophysics Data System (ADS)

Balzer, Frank; Schiek, Manuela; Osadnik, Andreas; Lützen, Arne; Rubahn, Horst-Günter

2012-02-01

Environmentally stable, non-toxic squarylium dyes with strong absorption maxima in the red and near infrared spectral region are known for almost fifty years. Despite the fact that their optoelectronic properties distinguish them as promising materials for organics based photovoltaic cells, they have regained attention only very recently. For their application in heterojunction solar cells knowledge of their nanoscopic morphology as well as nanoscopic electrical properties is paramount. In this paper thin films from two different squarylium dyes, from squarylium (SQ) and from hydroxy-squarylium (SQOH) are investigated. The thin films are either solution casted or vacuum sublimed onto substrates such as muscovite mica, which are known to promote self-assembly into oriented, crystalline nanostructures such as nanofibers. Local characterization is performed via (polarized) optical microscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), and Kelvin probe force microscopy (KPFM).

Development of Metallic Fuels for Actinide Transmutation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hayes, Steven Lowe; Fielding, Randall Sidney; Benson, Michael Timothy

Research and development activities on metallic fuels are focused on their potential use for actinide transmutation in future sodium fast reactors. As part of this application, there is also a need for a near zero-loss fabrication process and a desire to demonstrate a multifold increase in burnup potential. The incorporation of Am and Np into the traditional U-20Pu-10Zr metallic fuel alloy was demonstrated in the US during the Integral Fast Reactor Program of the 1980’s and early 1990’s. However, the conventional counter gravity injection casting method performed under vacuum, previously used to fabricate these metallic fuel alloys, was not optimizedmore » for mitigating loss of the volatile Am constituent in the casting charge; as a result, approximately 40% of the Am casting charge failed to be incorporated into the as-cast fuel alloys. Fabrication development efforts of the past few years have pursued an optimized bottom-pour casting method to increase utilization of the melted charge to near 100%, and a differential pressure casting approach, performed under an argon overpressure, has been demonstrated to result in essentially no loss of Am due to volatilization during fabrication. In short, a path toward zero-loss fabrication of metallic fuels including minor actinides has been shown to be feasible. Irradiation testing of advanced metallic fuel alloys in the Advanced Test Reactor (ATR) has been underway since 2003. Testing in the ATR is performed inside of cadmium-shrouded positions to remove >99% of the thermal flux incident on the test fuels, resulting in an epi-thermal driven fuel test that is free from gross flux depression and producing an essentially prototypic radial temperature profile inside the fuel rodlets. To date, three irradiation test series (AFC-1,2,3) have been completed. Over 20 different metallic fuel alloys have been tested to burnups as high as 30% with constituent compositions of Pu up to 30%, Am up to 12%, Np up to 10%, and Zr between 10 and 60%. In general, the performance of all of these substantially disparate metallic fuel alloys has been observed to be excellent, and their irradiation behaviors are generally consistent with historic norms for metallic fuels without minor actinide additions and having lower Pu or Zr contents. Future work is being undertaken with a view toward increasing the burnup potential of metallic fuels even more. Design innovations under investigation include: 1) lowering the fuel smear density in order to accommodate more swelling, 2) annular fuel geometry to eliminate the need for a sodium bond, 3) minor alloy additions to stabilize lanthanide fission products inside the fuel and prevent their transport to the cladding where they can participate in fuel-cladding chemical interaction (FCCI), and 4) coatings/liners on the cladding inner surface to mitigate FCCI and enable higher temperature operation. This paper will present the current state of development of metallic fuels for actinide transmutation in the US. Highlights will include recent results from metallic fuel casting experiments, experiments to identify alloy additions to immobilize lanthanide fission products, and postirradiation examinations of annular metallic fuels at low burnup.« less

Manufacturing Demonstration Facility: Roll-to-Roll Processing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Datskos, Panos G; Joshi, Pooran C; List III, Frederick Alyious

This Manufacturing Demonstration Facility (MDF)e roll-to-roll processing effort described in this report provided an excellent opportunity to investigate a number of advanced manufacturing approaches to achieve a path for low cost devices and sensors. Critical to this effort is the ability to deposit thin films at low temperatures using nanomaterials derived from nanofermentation. The overarching goal of this project was to develop roll-to-roll manufacturing processes of thin film deposition on low-cost flexible substrates for electronics and sensor applications. This project utilized ORNL s unique Pulse Thermal Processing (PTP) technologies coupled with non-vacuum low temperature deposition techniques, ORNL s clean roommore » facility, slot dye coating, drop casting, spin coating, screen printing and several other equipment including a Dimatix ink jet printer and a large-scale Kyocera ink jet printer. The roll-to-roll processing project had three main tasks: 1) develop and demonstrate zinc-Zn based opto-electronic sensors using low cost nanoparticulate structures manufactured in a related MDF Project using nanofermentation techniques, 2) evaluate the use of silver based conductive inks developed by project partner NovaCentrix for electronic device fabrication, and 3) demonstrate a suite of low cost printed sensors developed using non-vacuum deposition techniques which involved the integration of metal and semiconductor layers to establish a diverse sensor platform technology.« less

Northwestern University Flexible Subischial Vacuum Socket for persons with transfemoral amputation-Part 1: Description of technique

PubMed Central

Fatone, Stefania; Caldwell, Ryan

2017-01-01

Background: Current transfemoral prosthetic sockets restrict function, lack comfort, and cause residual limb problems. Lower proximal trim lines are an appealing way to address this problem. Development of a more comfortable and possibly functional subischial socket may contribute to improving quality of life of persons with transfemoral amputation. Objectives: The purpose of this study was to (1) describe the design and fabrication of a new subischial socket and (2) describe efforts to teach this technique. Study design: Development project. Methods: Socket development involved defining the following: subject and liner selection, residual limb evaluation, casting, positive mold rectification, check socket fitting, definitive socket fabrication, and troubleshooting of socket fit. Three hands-on workshops to teach the socket were piloted and attended by 30 certified prosthetists and their patient models. Results: Patient models responded positively to the comfort, range of motion, and stability of the new socket while prosthetists described the technique as “straight forward, reproducible.” Conclusion: To our knowledge, this is the first attempt to create a teachable subischial socket, and while it appears promising, more definitive evaluation is needed. Clinical relevance We developed the Northwestern University Flexible Subischial Vacuum (NU-FlexSIV) Socket as a more comfortable alternative to current transfemoral sockets and demonstrated that it could be taught successfully to prosthetists. PMID:28094686

Progress in joining, reuse, and customization of WR284 waveguide in the laboratory

NASA Astrophysics Data System (ADS)

Clark, Mike; Flanagan, Ken; Milhone, Jason; Nonn, Paul; Forest, Cary

2017-10-01

A system of five 20 kW magnetrons is being installed for the Big Red Ball (BRB) to produce and heat the plasma with 2.45GHz RF energy. An existing system of two 6 kW magentrons of the same frequency is actively used for the same purpose on Plasma Couette Experiment Upgrade (PCX-U). In each experiment, the RF is transmitted to the vessel via WR284 waveguide. Waveguide occasionally needs to be disassembled, modified and rebuilt for different reasons such as physics interests, ongoing problems (arcing), or efficient utilization of laboratory space. Reuse of disassembled waveguide parts is desirable for cost savings. Methods of assembly, disassembly, and modification of waveguide will be discussed. Also, frequently used designs of chokes, windows, and limiters will be shown. Materials used include copper, brass, and even aluminum. The vacuum vessel of PCX-U is a 1 meter diameter, 1 meter tall cylinder comprised of ¼'' thick stainless steel. PCX-U has one removable end. The vacuum vessel of the BRB is a 3 meter diameter, sphere comprised of two hemispheres of 1-¼'' thick cast A356 aluminum. Rings comprised of hundreds of SmCo magnets in each vessel create a cusp field to contain the plasma and provide a resonance surface for the RF. Supported by NSF and DoE.

New solar axion search using the CERN Axion Solar Telescope with He 4 filling

DOE PAGES

Arik, M.; Aune, S.; Barth, K.; ...

2015-07-28

The CERN Axion Solar Telescope (CAST) searches for a → γ conversion in the 9 T magnetic field of a refurbished LHC test magnet that can be directed toward the Sun. Two parallel magnet bores can be filled with helium of adjustable pressure to match the x-ray refractive mass m γ to the axion search mass m a. After the vacuum phase (2003–2004), which is optimal for m a ≲ 0.02 eV , we used 4He in 2005–2007 to cover the mass range of 0.02–0.39 eV and 3He in 2009–2011 to scan from 0.39 to 1.17 eV. After improving themore » detectors and shielding, we returned to 4He in 2012 to investigate a narrow m a range around 0.2 eV (“candidate setting” of our earlier search) and 0.39–0.42 eV, the upper axion mass range reachable with 4He , to “cross the axion line” for the KSVZ model. We have improved the limit on the axion-photon coupling to g aγ < 1.47 × 10 - 10 GeV - 1 (95% C.L.), depending on the pressure settings. Since 2013, we have returned to the vacuum and aim for a significant increase in sensitivity.« less

Novel carbon-ion fuel cells. Final report, October 1, 1993--September 30, 1996

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cocks, F.H.

1997-01-01

Mixed lanthanide dicarbides having the fluorite crystal structure have been synthesized using the elemental lanthanide metals and elemental carbon that was 99.9% pure carbon-13 isotope. A two step process of first, arc furnace melting of the components, followed by an annealing step in a high vacuum furnace, was adopted as the standard method of fabricating small cast ingots of the dicarbides. The crystal structure of the various lanthanide dicarbides produced were confirmed by x-ray diffraction under protective atmospheres at both room temperature at Duke University and at high temperature at Oak Ridge National Laboratory. After more than 15 combinations ofmore » cerium or lanthanum with dopants were tried, low temperature x-ray diffraction showed that Ce{sub .5}Er{sub .5}C{sub 2} had been successfully stabilized and had the desired fluorite crystal structure at room temperature. The fluorite crystal structure lanthanide dicarbide cast ingots were further prepared by having flat and clean surfaces ground onto their surfaces by high-speed milling machines inside argon gas atmosphere gloveboxes. The surfaces thus created were then coated with carbon-12 by the arc evaporation method under low pressure argon gas. The coated ingots were then allowed to have carbon diffusion occur from the surface coating of carbon-12 into the ingot of dicarbide that had been synthesized from carbon-13. After the diffusion run, the cast ingots were slit down the axis perpendicular to the carbon coating. The fracture surface created was then squared and polished by high,speed milling in a glove box with a argon atmosphere. The high diffusion co-efficient of carbon in lanthanide dicarbides having the fluorite crystal structure would make possible the manufacture of a carbon-ion electrolyte for use in a battery or a fuel cell that could consume solid carbon as it`s feedstock.« less

Study of formation mechanism of incipient melting in thixo-cast Al–Si–Cu–Mg alloys

DOE Office of Scientific and Technical Information (OSTI.GOV)

Du, Kang, E-mail: du126kang@126.com; Zhu, Qiang, E-mail: zhu.qiang@grinm.com; Li, Daquan, E-mail: lidaquan@grinm.com

Mechanical properties of thixo-cast Al–Si–Cu–Mg alloys can be enhanced by T61 heat treatment. Copper and magnesium atoms in aluminum matrix can form homogeneously distributed precipitations after solution and aging treatment which harden the alloys. However, microsegregation of these alloying elements could form numerous tiny multi-compound phases during solidification. These phases could cause incipient melting defects in subsequent heat treatment process and degrade the macro-mechanical properties of productions. This study is to present heterogeneous distribution of Cu, Si, and Mg elements and formation of incipient melting defects (pores). In this study, incipient melting pores that occurred during solution treatment at variousmore » temperatures, even lower than common melting points of various intermetallic phases, were identified, in terms of a method of investigating the same surface area in the samples before and after solution treatment in a vacuum environment. The results also show that the incipient melting mostly originates at the clusters with fine intermetallic particles while also some at the edge of block-like Al{sub 2}Cu. The fine particles were determined being Al{sub 2}Cu, Al{sub 5}Cu{sub 2}Mg{sub 8}Si{sub 6} and Al{sub 8}Mg{sub 3}FeSi{sub 2}. Tendency of the incipient melting decreases with decreases of the width of the clusters. The formation mechanism of incipient melting pores in solution treatment process was discussed using both the Fick law and the LSW theory. Finally, a criterion of solution treatment to avoid incipient melting pores for the thixo-cast alloys is proposed. - Highlights: • In-situ comparison technique was used to analysis the change of eutectic phases. • The ralationship between eutectic phase size and incipient melting was studied. • Teat treatment criterion for higher incipient melting resistance was proposed.« less

Development of a full-length external-fuel thermionic converter for in-pile testing.

NASA Technical Reports Server (NTRS)

Schock, A.; Raab, B.

1971-01-01

Description of an external-fuel thermionic converter which utilizes a thoriated-tungsten fuel-emitter body. Performance in out-of-pile tests was comparable to that of an arc-cast tungsten emitter body, with 400-eW output power (about 5 W/sq cm) at 10.8% efficiency. Maximum fuel clad temperature averaged from 1650 to 1700 C during the 300-hour test. This converter has been processed for in-pile testing. The various processing steps, including the installation of six emitter thermocouples, encapsulation in the secondary container, and joining to the fission-gas collection system, are described in detail. In addition to the converter assembly, a doubly contained fission gas collection assembly with radiation-hardened differential pressure transducers was fabricated. The experiment support plate required for the in-pile test, containing electrically insulated instrumentation feedthroughs and coolant line feedthroughs to the vacuum test chamber, was also fabricated.

Fabrication and Testing of a Leading-Edge-Shaped Heat Pipe

NASA Technical Reports Server (NTRS)

Glass, David E.; Merrigan, Michael A.; Sena, J. Tom; Reid, Robert S.

1998-01-01

The development of a refractory-composite/heat-pipe-cooled leading edge has evolved from the design stage to the fabrication and testing of a full size, leading-edge-shaped heat pipe. The heat pipe had a 'D-shaped' cross section and was fabricated from arc cast Mo-4lRe. An artery was included in the wick. Several issues were resolved with the fabrication of the sharp leading edge radius heat pipe. The heat pipe was tested in a vacuum chamber at Los Alamos National Laboratory using induction heating and was started up from the frozen state several times. However, design temperatures and heat fluxes were not obtained due to premature failure of the heat pipe resulting from electrical discharge between the induction heating apparatus and the heat pipe. Though a testing anomaly caused premature failure of the heat pipe, successful startup and operation of the heat pipe was demonstrated.

Aesthetic finger prosthesis with silicone biomaterial

PubMed Central

Raghu, K M; Gururaju, C R; Sundaresh, K J; Mallikarjuna, Rachappa

2013-01-01

The fabrication of finger prosthesis is as much an art as it is science. The ideally constructed prosthesis must duplicate the missing structures so precisely that patients can appear in public without fear of attracting unwanted attraction. A 65-years-old patient reported with loss of his right index finger up to the second phalanx and wanted to get it replaced. An impression of the amputated finger and donor were made. A wax pattern of the prosthesis was fabricated using the donor impression; a trial was performed and flasked. Medical grade silicone was intrinsically stained to match the skin tone, following which it was packed, processed and finished. This clinical report describes a method of attaining retention by selective scoring of the master cast of partially amputated finger to enhance the vacuum effect at par with the proportional distribution of the positive forces on the tissues exerted by the prosthesis. PMID:23975917

MoNbTaV Medium-Entropy Alloy

DOE PAGES

Yao, Hongwei; Qiao, Jun -Wei; Gao, Michael; ...

2016-05-19

Guided by CALPHAD (Calculation of Phase Diagrams) modeling, the refractory medium-entropy alloy MoNbTaV was synthesized by vacuum arc melting under a high-purity argon atmosphere. A body-centered cubic solid solution phase was experimentally confirmed in the as-cast ingot using X-ray diffraction and scanning electron microscopy. The measured lattice parameter of the alloy (3.208 Å) obeys the rule of mixtures (ROM), but the Vickers microhardness (4.95 GPa) and the yield strength (1.5 GPa) are about 4.5 and 4.6 times those estimated from the ROM, respectively. Using a simple model on solid solution strengthening predicts a yield strength of approximately 1.5 GPa. Inmore » conclusion, thermodynamic analysis shows that the total entropy of the alloy is more than three times the configurational entropy at room temperature, and the entropy of mixing exhibits a small negative departure from ideal mixing.« less

Carbon-free induction furnace

DOEpatents

Holcombe, Cressie E.; Masters, David R.; Pfeiler, William A.

1985-01-01

An induction furnace for melting and casting highly pure metals and alloys such as uranium and uranium alloys in such a manner as to minimize contamination of the melt by carbon derived from the materials and the environment within the furnace. The subject furnace is constructed of carbon free materials and is housed within a conventional vacuum chamber. The furnace comprises a ceramic oxide crucible for holding the charge of metal or alloy. The heating of the crucible is achieved by a plasma-sprayed tungsten susceptor surrounding the crucible which, in turn, is heated by an RF induction coil separated from the susceptor by a cylinder of inorganic insulation. The furnace of the present invention is capable of being rapidly cycled from ambient temperatures to about 1650.degree. C. for effectively melting uranium and uranium alloys without the attendant carbon contamination problems previously encountered when using carbon-bearing furnace materials.

Non-carbon induction furnace

DOEpatents

Holcombe, C.E.; Masters, D.R.; Pfeiler, W.A.

1984-01-06

The present invention is directed to an induction furnace for melting and casting highly pure metals and alloys such as uranium and uranium alloys in such a manner as to minimize contamination of the melt by carbon derived from the materials and the environment within the furnace. The subject furnace is constructed of non-carbon materials and is housed within a conventional vacuum chamber. The furnace comprises a ceramic oxide crucible for holding the charge of metal or alloys. The heating of the crucible is achieved by a plasma-sprayed tungsten susceptor surrounding the crucible which, in turn, is heated by an rf induction coil separated from the susceptor by a cylinder of inorganic insulation. The furnace of the present invention is capable of being rapidly cycled from ambient temperatures to about 1650/sup 0/C for effectively melting uranium and uranium alloys without the attendant carbon contamination problems previously encountered when using carbon-bearing furnace materials.

Powder processing of hybrid titanium neural electrodes

NASA Astrophysics Data System (ADS)

Lopez, Jose Luis, Jr.

A preliminary investigation into the powder production of a novel hybrid titanium neural electrode for EEG is presented. The rheological behavior of titanium powder suspensions using sodium alginate as a dispersant are examined for optimal slip casting conditions. Electrodes were slip cast and sintered at 950°C for 1 hr, 1000°C for 1, 3, and 6 hrs, and 1050°C for 1 hr. Residual porosities from sintering are characterized using Archimedes' technique and image analysis. The pore network is gel impregnated by submerging the electrodes in electrically conductive gel and placing them in a chamber under vacuum. Gel evaporation of the impregnated electrodes is examined. Electrodes are characterized in the dry and gelled states using impedance spectrometry and compared to a standard silver- silver chloride electrode. Power spectral densities for the sensors in the dry and gelled state are also compared. Residual porosities for the sintered specimens were between 50.59% and 44.81%. Gel evaporation tests show most of the impregnated gel evaporating within 20 min of exposure to atmospheric conditions with prolonged evaporation times for electrodes with higher impregnated gel mass. Impedance measurements of the produced electrodes indicate the low impedance of the hybrid electrodes are due to the increased contact area of the porous electrode. Power spectral densities of the titanium electrode behave similar to a standard silver-silver chloride electrode. Tests suggest the powder processed hybrid titanium electrode's performance is better than current dry contact electrodes and comparable to standard gelled silver-silver chloride electrodes.

Evaluation of the Low Heat Input Process for Weld Repair of Nickel-Base Superalloys

NASA Astrophysics Data System (ADS)

Durocher, J.; Richards, N. L.

2011-10-01

The repair of turbine blades and vanes commonly involves gas tungsten arc welding or an equivalent process, but unfortunately these components are often susceptible to heat-affected zone (HAZ) cracking during the weld repair process. This is a major problem especially in cast alloys due to their coarse-grain size and where the (Al + Ti) contents is in excess of 3-4%; vacuum brazing is also used but mainly on low stress non-rotating components such as vanes. Micro-welding has the potential to deposit small amounts of filler at low heat input levels with minimum HAZ and thus is an attractive process for depositing a quality weld. As with conventional fusion processes, the filler alloy is deposited by the generation of a low power arc between a consumable electrode and the substrate. The low heat input of this process offers unique advantages over more common welding processes such as gas tungsten arc, plasma arc, laser, and electron beam welding. In this study, the low heat input characteristic of micro-welding has been used to simulate weld repair using Inconel (IN) (Inconel and IN are trademarks of INCO Alloys International) 625, Rene (Rene is a trademark of General Electric Company) 41, Nimonic (Nimonic is a trademark of INCO Alloys International) 105 and Inconel 738LC filler alloys, to a cast Inconel 738LC substrate. The effect of micro-welding process parameters on the deposition rate, coating quality, and substrate has been investigated.

Tensile strength comparison of presoldered and postsoldered joints.

PubMed

Monday, J J; Asgar, K

1986-01-01

Twenty half-dumbbell shaped rods were cast in a silverless gold-palladium alloy that contained a minimum of 42% fresh alloy and the rest once-melted alloy. Each pair of half-dumbbells was assembled and either presoldered or postsoldered using a vacuum-oven and a torch-soldering technique. There was no significant difference in the ultimate tensile strength values between the presoldered and postsoldered joints within the same technique group, but the torch-soldered joints for the same solder were significantly stronger (p less than .01). It was believed that slow heating and cooling has deleterious effects on the ultimate tensile strength joints (UTS) possibly because of the microstructural changes and the highly oxidizable content of the postsolder used. Another 15 samples cast using once, twice, and three-times remelted parent alloy were presoldered and postsoldered with the torch only. In each of these groups, specimens joined by presolder showed significantly higher strength than those joined by postsolder (p less than .02). Remelting the parent alloy affected the strength differences between the presoldered and postsoldered joints. It was assumed that on remelting, the nature of the parent alloy is changed because some original elements are volatilized and newly formed oxides dissolved into it. Because it contains copper, the postsolder is more affected by this contamination than presolder. The UTS of the parent alloy, as well as that of the presolder and postsolder, were also determined. As expected, the parent alloy possessed the highest strength and the postsolder, the lowest.

Thermophysical Properties of Cold and Vacuum Plasma Sprayed Cu-Cr-X Alloys, NiAl and NiCrAlY Coatings. Part 2; Specific Heat Capacity

NASA Technical Reports Server (NTRS)

Raj, S. V.

2017-01-01

Part I of the paper discussed the temperature dependencies of the electrical resistivities, thermal conductivities, thermal diffusivities and total hemispherical emissivities of several vacuum plasma sprayed (VPS) and cold sprayed copper alloy monolithic coatings, VPS NiAl, VPS NiCrAlY, extruded GRCop-84 and as-cast Cu-17(wt.%)Cr-5%Al. Part II discusses the temperature dependencies of the constant pressure specific heat capacities, CP, of these coatings. The data were empirically were regression-fitted with the equation: CP = AT4 + BT3 + CT2 + DT +E where T is the absolute temperature and A, B, C, D and E are regression constants. The temperature dependencies of the molar enthalpy, molar entropy and Gibbs molar free energy determined from experimental values of molar specific heat capacity are reported. Calculated values of CP using the Neumann-Kopp (NK) rule were in poor agreement with experimental data. Instead, a modification of the Neumann-Kopp rule was found to predict values closer to the experimental data with an absolute deviation less than 6.5%. The specific molar heat capacities for all the alloys did not agree with the Dulong-Petit law, and CP is greater than 3R, where R is the universal gas constant, were measured for all the alloys except NiAl for which CP is less than 3R at all temperatures.

Thermophysical Properties of Cold- and Vacuum Plasma-Sprayed Cu-Cr-X Alloys, NiAl and NiCrAlY Coatings II: Specific Heat Capacity

NASA Astrophysics Data System (ADS)

Raj, S. V.

2017-11-01

Part I of the paper discussed the temperature dependencies of the electrical resistivities, thermal conductivities, thermal diffusivities and total hemispherical emissivities of several vacuum plasma-sprayed (VPS) and cold-sprayed (CS) copper alloy monolithic coatings, VPS NiAl, VPS NiCrAlY, extruded GRCop-84 and as-cast Cu-17(wt.%)Cr-5%Al. Part II discusses the temperature dependencies of the constant-pressure specific heat capacities, C P, of these coatings. The data were empirically regression-fitted with the equation: \\varvec{C}_{P} = {AT}^{4} + {BT}^{3} + {CT}^{2} + DT + \\varvec{E}where T is the absolute temperature and A, B, C, D and E are regression constants. The temperature dependencies of the molar enthalpy, molar entropy and Gibbs molar free energy determined from experimental values of molar specific heat capacity are reported. Calculated values of C P using the Neumann-Kopp (NK) rule were in poor agreement with experimental data. Instead, a modification of the NK rule was found to predict values closer to the experimental data with an absolute deviation less than 6.5%. The specific molar heat capacities for all the alloys did not agree with the Dulong-Petit law, and C P > 3 R, where R is the universal gas constant, were measured for all the alloys except NiAl for which C P < 3 R at all temperatures.

Antimicrobial evaluation of novel poly-lactic acid based nanocomposites incorporated with bioactive compounds in-vitro and in refrigerated vacuum-packed cooked sausages.

PubMed

Rezaeigolestani, Mohammadreza; Misaghi, Ali; Khanjari, Ali; Basti, Afshin Akhondzadeh; Abdulkhani, Ali; Fayazfar, Samira

2017-11-02

Biodegradability and antimicrobial activity of food packaging materials are among the most attractive parameters in modern food industries. In order to develop biodegradable poly-lactic acid (PLA) film to antibacterial nanocomposites, different concentration of Zataria multiflora Bioss. essential oil (ZME), propolis ethanolic extract (PEE) and cellulose nanofiber (CNF) were incorporated to the polymer by solvent casting method. The resulting films were characterized by mechanical and physical tests and their antimicrobial application was evaluated in-vitro against four common foodborne pathogens and in vacuum-packed cooked sausages during refrigerated storage. Mechanical examination revealed that addition of ZME and PEE made films more flexible and incorporation of CNF improved almost all mechanical parameters tested. Moreover, according to physical analysis, incorporation of 0.5% v/v ZME to the composite primary solutions improved water vapor permeability of the resulting films. Almost all of the active films were effective against the tested bacteria except for PLA/PEE films, and maximum antibacterial effects recorded for the films containing both ZME and PEE. Based on the microbiological and sensory evaluation of the sausages, all of the PLA/1%ZME/PEE composites increased the shelf life to >40days. The results indicate that incorporation of natural antimicrobial substances such as ZME and PEE to packaging material could be an interesting approach in development of active packaging material without significant negative effect on polymer technical properties. Copyright © 2017 Elsevier B.V. All rights reserved.

Effect of Casting Material on the Cast Pressure After Sequential Cast Splitting.

PubMed

Roberts, Aaron; Shaw, K Aaron; Boomsma, Shawn E; Cameron, Craig D

2017-01-01

Circumferential casting is a vital component of nonoperative fracture management. These casts are commonly valved to release pressure and decrease the risk of complications from swelling. However, little information exists regarding the effect of different casting supplies on the pressure within the cast. Seventy-five long-arm casts were performed on human volunteers, divided between 5 experimental groups with 15 casts in each groups. Testing groups consisted of 2 groups with a plaster short-arm cast overwrapped with fiberglass to a long arm with either cotton or synthetic cast padding. The 3 remaining groups included fiberglass long-arm casts with cotton, synthetic, or waterproof cast padding. A pediatric blood pressure cuff bladder was placed within the cast and inflated to 100 mm Hg. After inflation, the cast was sequentially released with pressure reading preformed after each stage. Order of release consisted of cast bivalve, cast padding release, and cotton stockinet release. After release, the cast was overwrapped with a loose elastic bandage. Difference in pressure readings were compared based upon the cast material. Pressures within the cast were found to decrease with sequential release of cast. The cast type had no effect of change in pressure. Post hoc testing demonstrated that the type of cast padding significantly affected the cast pressures with waterproof padding demonstrating the highest pressure readings at all time-points in the study, followed by synthetic padding. Cotton padding had the lowest pressure readings at all time-points. Type of cast padding significantly influences the amount of pressure within a long-arm cast, even after bivalving the cast and cutting the cast padding. Cotton cast padding allows for the greatest change in pressure. Cotton padding demonstrates the greatest change in pressure within a long-arm cast after undergoing bivalve. Synthetic and waterproof cast padding should not be used in the setting of an acute fracture to accommodate swelling.

Comparison of marginal accuracy of castings fabricated by conventional casting technique and accelerated casting technique: an in vitro study.

PubMed

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.

Fibreglass Total Contact Casting, Removable Cast Walkers, and Irremovable Cast Walkers to Treat Diabetic Neuropathic Foot Ulcers: A Health Technology Assessment

PubMed Central

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 cast walkers were less expensive and led to more health outcome gains (e.g., ulcers healed and quality-adjusted life-years) than removable cast walkers. Irremovable cast walkers were as effective as total contact casting and were associated with lower costs. The 5-year budget impact of funding total contact casting, removable cast walkers, and irremovable cast walkers (device costs only at 100% access) would be $17 to $20 million per year. The patients we interviewed felt that wound healing was improved with total contact casting than with removable cast walkers, but that removable cast walkers were more convenient and came with a lower cost burden. They reported no experience or familiarity with irremovable cast walkers. Conclusions Ulcer healing improved with total contact casting, irremovable cast walkers, and removable cast walkers, but total contact casting and irremovable cast walkers had higher rates of ulcer healing than removable cast walkers. Increased access to offloading devices could result in cost savings for the health system because of fewer amputations. Patients with diabetic foot ulcers reported a preference for total contact casting over removable cast walkers, largely because they perceived wound healing to be improved with total contact casting. However, cost, comfort, and convenience are concerns for patients. PMID:28989556

Fibreglass Total Contact Casting, Removable Cast Walkers, and Irremovable Cast Walkers to Treat Diabetic Neuropathic Foot Ulcers: A Health Technology Assessment.

PubMed

2017-01-01

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. 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. 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 cast walkers were less expensive and led to more health outcome gains (e.g., ulcers healed and quality-adjusted life-years) than removable cast walkers. Irremovable cast walkers were as effective as total contact casting and were associated with lower costs. The 5-year budget impact of funding total contact casting, removable cast walkers, and irremovable cast walkers (device costs only at 100% access) would be $17 to $20 million per year. The patients we interviewed felt that wound healing was improved with total contact casting than with removable cast walkers, but that removable cast walkers were more convenient and came with a lower cost burden. They reported no experience or familiarity with irremovable cast walkers. Ulcer healing improved with total contact casting, irremovable cast walkers, and removable cast walkers, but total contact casting and irremovable cast walkers had higher rates of ulcer healing than removable cast walkers. Increased access to offloading devices could result in cost savings for the health system because of fewer amputations. Patients with diabetic foot ulcers reported a preference for total contact casting over removable cast walkers, largely because they perceived wound healing to be improved with total contact casting. However, cost, comfort, and convenience are concerns for patients.

Soft cast versus rigid cast for treatment of distal radius buckle fractures in children.

PubMed

Witney-Lagen, Caroline; Smith, Christine; Walsh, Graham

2013-04-01

Buckle fractures are extremely common and their optimum management is still under debate. This study aimed to ascertain whether buckle fractures of the distal radius can be safely and effectively treated in soft cast with only a single orthopaedic outpatient clinic appointment. A total of 232 children with buckle fractures of the distal radius were included in the study. 111 children with 112 distal radius fractures were treated in full rigid cast and 121 children with 123 fractures were treated with soft cast. The rigid cast children attended outpatient clinic for removal of cast at 3 weeks. Soft casts were removed by parents unwinding the cast at home after 3 weeks. Follow-up was conducted prospectively by telephone questionnaire at an average of 6 weeks post-injury. Outcome data were available for 117 children treated in soft cast and for 102 children treated in rigid cast. The most common mechanism of injury was a fall sustained from standing or running, followed by falls from bikes and then trampoline accidents. Overall, both groups recovered well. Overall satisfaction with the outcome of treatment was 97.4% in soft cast and 95.2% in rigid cast. Casts were reported as comfortable by 95.7% in soft cast and 93.3% in rigid cast. Cast changes were required for 6.8% of soft casts and 11.5% of rigid casts. The most frequent cause for changing rigid casts was getting the cast wet. None of the improved scores seen in the soft cast group were statistically significant. No re-fractures were seen in either group. Nearly all (94.9%) children in soft cast did bathe, shower or swim in their cast. Parents of both groups preferred treatment with soft cast (p < 0.001). Reasons given for preferring the soft cast included the ability to get the cast wet, avoidance of the plaster saw and not having to take time off work to attend a follow-up visit for cast removal. Buckle fractures of the distal radius can be safely and effectively treated in soft cast with only a single orthopaedic outpatient clinic appointment. Copyright © 2012 Elsevier Ltd. All rights reserved.

Incidence and etiology of unplanned cast changes for fractures in the pediatric population.

PubMed

DiPaola, Matthew J; Abzug, Joshua M; Pizzutillo, Peter D; Herman, Martin J

2014-09-01

The majority of pediatric fractures are treated in casts due to the child's ability to heal rapidly and remodel. Unplanned cast changes are a time and economic burden with potentially adverse effects on fracture management. The purpose of this study is to document the incidence, etiology, and complications related to unplanned cast changes. A prospective study was conducted over a 6-month period to determine the incidence of unplanned cast changes. All casts applied were nonwaterproof. Data collected include the reason for cast placement, type of cast placed, duration of wear before the unplanned change, reason for the unplanned change, experience level of the original cast applicator, and cast-related complications. A total of 1135 casts were placed with 58% placed by a resident, 38% by a cast technician, 2% by a physician's assistant, and 2% by an attending physician. Sixty casts (5.3%) required an unplanned change including 19 short-arm casts, 18 short-leg casts, 17 long-arm casts, 4 thumb spica casts, and 2 long-leg casts. The average duration from cast application until the unplanned change was 13 days. Twenty-eight (47%) were changed for wetness, 20 (33%) for wear/breakage, 2 (3%) for skin irritation, and 10 (17%) for other reasons including objects in the cast and patient self-removal. Two patients had superficial skin infections requiring oral antibiotics. No fracture reductions were lost secondary to an unplanned cast change. The need for an unplanned cast change did not correlate with the level of experience of the applicator. Most unplanned cast changes were the result of patient nonadherence to instructions and not related to cast application technique. Improved patient and family education regarding cast care may reduce the frequency of unplanned cast changes, thus reducing an economic and time burden on the health care system. Level II--prognostic study.

A new experimental apparatus for emissivity measurements of steel and the application of multi-wavelength thermometry to continuous casting billets

NASA Astrophysics Data System (ADS)

Wang, Peng; Hu, Zhenwei; Xie, Zhi; Yan, Ming

2018-05-01

An experimental apparatus has been designed for measuring the emissivity of a steel surface in both vacuum and oxidation atmosphere. The sample is heated with the method of electromagnetic induction in order to ensure the temperature uniformity. The radiance emitted from a sample is measured using a fiber-optic Fourier transform infrared spectrometer. Using this unique apparatus, we investigated the spectral (2-6 μm) and directional (0°-86°) emissivity of stainless steel 304 with different degrees of surface oxidation at temperatures ranging from 800 to 1100 °C. The experimental results show that the emissivity increases slightly with increasing temperature, which accords with the Hagen-Rubens relation. The emissivity increases rapidly at the initial stage of oxidation, but gradually reaches to a constant value after 20 min. In addition, the directional emissivity has a maximum value at the measuring angle of about 75°. The maximum uncertainty of emissivity is only 3.0% over all the measuring ranges, indicating that this experimental apparatus has a high reliability. In order to measure the surface temperature of casting billets based on multi-wavelength thermometry, the bivariate emissivity function with the two variables, wavelength and temperature, is determined. Temperature measurement results based on our technique are compared with those from common dual-wavelength radiation thermometry. Our approach reduces the measured temperature fluctuation from ±20.7 °C to ±2.8 °C and reflects the temperature variation with the changes of production parameters in real time.

Solid State Digital Propulsion "Cluster Thrusters" For Small Satellites Using High Performance Electrically Controlled Extinguishable Solid Propellants (ECESP)

NASA Technical Reports Server (NTRS)

Sawka, Wayne N.; Katzakian, Arthur; Grix, Charles

2005-01-01

Electrically controlled extinguishable solid propellants (ESCSP) are capable of multiple ignitions, extinguishments and throttle control by the application of electrical power. Both core and end burning no moving parts ECESP grains/motors to three inches in diameter have now been tested. Ongoing research has led to a newer family of even higher performance ECESP providing up to 10% higher performance, manufacturing ease, and significantly higher electrical conduction. The high conductivity was not found to be desirable for larger motors; however it is ideal for downward scaling to micro and pico- propulsion applications with a web thickness of less than 0.125 inch/ diameter. As a solid solution propellant, this ECESP is molecularly uniform, having no granular structure. Because of this homogeneity and workable viscosity it can be directly cast into thin layers or vacuum cast into complex geometries. Both coaxial and grain stacks have been demonstrated. Combining individual propellant coaxial grains and/or grain stacks together form three-dimensional arrays yield modular cluster thrusters. Adoption of fabless manufacturing methods and standards from the electronics industry will provide custom, highly reproducible micro-propulsion arrays and clusters at low costs. These stack and cluster thruster designs provide a small footprint saving spacecraft surface area for solar panels and/or experiments. The simplicity of these thrusters will enable their broad use on micro-pico satellites for primary propulsion, ACS and formation flying applications. Larger spacecraft may find uses for ECESP thrusters on extended booms, on-orbit refueling, pneumatic actuators, and gas generators.

Reducing the Incidence of Cast-related Skin Complications in Children Treated With Cast Immobilization.

PubMed

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.

Determining casting defects in near-net shape casting aluminum parts by computed tomography

NASA Astrophysics Data System (ADS)

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.

The effect of microstructure and strength on the fracture toughness of an 18 Ni, 300 grade maraging steel

NASA Technical Reports Server (NTRS)

Psioda, J. A.; Low, J. R., Jr.

1975-01-01

A 300 grade maraging steel was chosen as a vehicle by which to understand the inverse relationship between strength and toughness in high strength alloys such as the 18 Ni maraging steels. The 18 Ni, 300 grade maraging material was a commercial grade consumable-electrode, vacuum arc remelted heat obtained in the form of forged and annealed plate. The matrix contained a population of second-phase impurity inclusions which was a product of the casting and hot working processes. These inclusions did not change with subsequent precipitation hardening. Changes in microstructure resulting in strength increases were brought about by variations in aging temperature and time. Maximum strength was attained in the 300 grade maraging steel by aging at 427 C (800 F) for 100 hours. Tensile, fatigue precracked Charpy impact, and plane-strain fracture toughness tests were performed at room temperature, 20 C (68 F). With increasing strength the fracture toughness decreases as smaller and smaller inclusions act as sites for void initiation.

Trace element control in binary Ni-25Cr and ternary Ni-30Co-30Cr master alloy castings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Detrois, Martin; Jablonski, Paul D.

Electro-slag remelting (ESR) is used for control of unwanted elements in commercial alloys. This study focuses on master alloys of Ni-25Cr and Ni-30Co-30Cr, processed through a combination of vacuum induction melting (VIM) and electro-slag remelting (ESR). Minor additions were made to control tramp element levels and modify the melting characteristics. Nitrogen and sulfur levels below 10 ppm and oxygen levels below 100 ppm were obtained in the final products. The role of the alloy additions in lowering the tramp element content, the resulting residual inclusions and the melting characteristics were determined computationally and confirmed experimentally. Additions of titanium were beneficialmore » to the control of oxygen levels during VIM and nitrogen levels during ESR. Aluminum additions helped to control oxygen levels during remelting, however, aluminum pickup occurred when excess titanium was present during ESR. The usefulness of these master alloys for use as experimental remelt stock will also be discussed.« less

Thermally insulating and fire-retardant lightweight anisotropic foams based on nanocellulose and graphene oxide.

PubMed

Wicklein, Bernd; Kocjan, Andraž; Salazar-Alvarez, German; Carosio, Federico; Camino, Giovanni; Antonietti, Markus; Bergström, Lennart

2015-03-01

High-performance thermally insulating materials from renewable resources are needed to improve the energy efficiency of buildings. Traditional fossil-fuel-derived insulation materials such as expanded polystyrene and polyurethane have thermal conductivities that are too high for retrofitting or for building new, surface-efficient passive houses. Tailored materials such as aerogels and vacuum insulating panels are fragile and susceptible to perforation. Here, we show that freeze-casting suspensions of cellulose nanofibres, graphene oxide and sepiolite nanorods produces super-insulating, fire-retardant and strong anisotropic foams that perform better than traditional polymer-based insulating materials. The foams are ultralight, show excellent combustion resistance and exhibit a thermal conductivity of 15 mW m(-1) K(-1), which is about half that of expanded polystyrene. At 30 °C and 85% relative humidity, the foams retained more than half of their initial strength. Our results show that nanoscale engineering is a promising strategy for producing foams with excellent properties using cellulose and other renewable nanosized fibrous materials.

Robust, easily shaped, and epoxy-free carbon-fiber-aluminum cathodes for generating high-current electron beams.

PubMed

Liu, Lie; Li, Limin; Wen, Jianchun; Wan, Hong

2009-02-01

This paper presents the construction of carbon-fiber-aluminum (CFA) cathode by squeezing casting and its applications for generating high-current electron beams to drive high-power microwave sources. The fabrication process avoided using epoxy, a volatile deteriorating the vacuum system. These cathodes had a higher hardness than conventional aluminum, facilitating machining. After surface treatment, carbon fibers became the dominator determining emission property. A multineedle CFA cathode was utilized in a triode virtual cathode oscillator (vircator), powered by a approximately 450 kV, approximately 400 ns pulse. It was found that 300-400 MW, approximately 250 ns microwave was radiated at a dominant frequency of 2.6 GHz. Further, this cathode can endure high-current-density emission without detectable degradation in performance as the pulse shot proceeded, showing the robust nature of carbon fibers as explosive emitters. Overall, this new class of cold cathodes offers a potential prospect of developing high-current electron beam sources.

Mindfulness Broadens Awareness and Builds Eudaimonic Meaning: A Process Model of Mindful Positive Emotion Regulation

PubMed Central

Garland, Eric L.; Farb, Norman A.; Goldin, Philippe; Fredrickson, Barbara L.

2015-01-01

Contemporary scholarship on mindfulness casts it as a form of purely non-evaluative engagement with experience. Yet, traditionally mindfulness was not intended to operate in a vacuum of dispassionate observation, but was seen as facilitative of eudaimonic mental states. In spite of this historical context, modern psychological research has neglected to ask the question of how the practice of mindfulness affects downstream emotion regulatory processes to impact the sense of meaning in life. To fill this lacuna, here we describe the Mindfulness-to-Meaning Theory, from which we derive a novel process model of mindful positive emotion regulation informed by affective science, in which mindfulness is proposed to introduce flexibility in the generation of cognitive appraisals by enhancing interoceptive attention, thereby expanding the scope of cognition to facilitate reappraisal of adversity and savoring of positive experience. This process is proposed to culminate in a deepened capacity for meaning-making and greater engagement with life. PMID:27087765

Development of a collapsible reinforced cylindrical space observation window

NASA Technical Reports Server (NTRS)

Khan, A. Q.

1971-01-01

Existing material technology was applied to the development of a collapsible transparent window suitable for manned spacecraft structures. The effort reported encompasses the evaluation of flame retardants intended for use in the window matrix polymer, evaluation of reinforcement angle which would allow for a twisting pantographing motion as the cylindrical window is mechanically collapsed upon itself, and evaluation of several reinforcement embedment methods. A fabrication technique was developed to produce a reinforced cylindrical space window of 45.7 cm diameter and 61.0 cm length. The basic technique involved the application of a clear film on a male-section mold; winding axial and girth reinforcements and vacuum casting the outer layer. The high-strength transparent window composite consisted of a polyether urethane matrix reinforced with an orthogonal pattern of black-coated carbon steel wire cable. A thin film of RTV silicone rubber was applied to both surfaces of the urethane. The flexibility, retraction system, and installation system are described.

Fabrication of near-net shape graphite/magnesium composites for large mirrors

NASA Astrophysics Data System (ADS)

Wendt, Robert; Misra, Mohan

1990-10-01

Successful development of space-based surveillance and laser systems will require large precision mirrors which are dimensionally stable under thermal, static, and dynamic (i.e., structural vibrations and retargeting) loading conditions. Among the advanced composites under consideration for large space mirrors, graphite fiber reinforced magnesium (Gr/Mg) is an ideal candidate material that can be tailored to obtain an optimum combination of properties, including a high modulus of elasticity, zero coefficient of thermal expansion, low density, and high thermal conductivity. In addition, an innovative technique, combining conventional filament winding and vacuum casting has been developed to produce near-net shape Gr/Mg composites. This approach can significantly reduce the cost of fabricating large mirrors by decreasing required machining. However, since Gr/Mg cannot be polished to a reflective surface, plating is required. This paper will review research at Martin Marietta Astronautics Group on Gr/Mg mirror blank fabrication and measured mechanical and thermal properties. Also, copper plating and polishing methods, and optical surface characteristics will be presented.

Elevated temperature strengthening of a melt spun austenitic steel by TiB2

NASA Technical Reports Server (NTRS)

Michal, G. M.; Glasgow, T. K.; Moore, T. J.

1986-01-01

Mechanical properties of an iron-based alloy containing (by wt pct) 33Ni, 2Al, 6Ti, and 2B (resulting in an alloy containing 10 vol pct TiB2) were evaluated by hardness and tensile testing. The alloy was cast as a ribbon using a dual 'free-jet' variation of Jech et al. (1984) method of chill-block melt-spinning against a copper wheel; to simulate thermal cycles the alloy ribbon would experience during compaction into shapes, various segments of the ribbon were annealed under a vacuum at temperatures ranging from 500 to 1150 C. The results show that maximum strengths at 650 and 760 C were developed in ribbons annealed at 1100 C; in these ribbons an optimal combination of grain coarsening with minimum TiB2 particle growth was observed. However, the elevated-temperature strength of the TiB2-strengthened alloy under optimal annealing conditions was poorer than that of conventional iron-based superalloys strengthened by gamma-prime precipitates.

Non-Metallic Ti Oxides and MnS/FeS2 Complex Precipitation in Ti-Killed Steel

NASA Astrophysics Data System (ADS)

Chen, Jieyun; Zhao, Dan; Li, Huigai; Zheng, Shaobo

Titanium deoxidized experiments can be carried in vacuum induction furnace by adding Ti-Fe alloy in molten steel to simulate strip casting. Sub-rapid solidification samples were obtained in the method of suing copper mold. The morphology, the chemical composition and the structures of nanometer precipitations were carried out to investigate by transmission electron microscope (TEM) with Energy Dispersive X ray Spectrum (EDX) and by collecting diffraction patterns with carbon extraction specimens. It has been found that titanium oxides were TiO monoclinic, Ti4O7 anorthic and TiO2 orthogonal structure in one nanometer inclusion, as the composite oxide was precipitated MnS/FeS2 cubic structure during sub-rapid solidification. Thermodynamic calculation analysis showed that it was possible to precipitate different kinds of nonstoichiometric TiOx. The solid solution between MnS/FeS2 will precipitate on the surface of titanium oxides because of good coherency relationship.

New multifunctional materials obtained by the intercalation of anionic dyes into layered zinc hydroxide nitrate followed by dispersion into poly(vinyl alcohol) (PVA).

PubMed

Marangoni, Rafael; Ramos, Luiz Pereira; Wypych, Fernando

2009-02-15

Different anionic blue and orange dyes have been immobilized on a zinc hydroxide nitrate (Zn(5)(OH)(8)(NO(3))(2)nH(2)O--Zn-OH-NO(3)) by anion exchange with interlayer and/or outer surface nitrate ions of the layered matrix. Orange G (OG) was totally intercalated, orange II (OII) was partially intercalated, while Niagara blue 3B (NB) and Evans blue (EV) were only adsorbed at the outer surface. Several composite films of poly(vinyl alcohol)--PVA were prepared by casting through the dispersion of the hybrid material (Zn-OH-OG) into a PVA aqueous solution and evaporation of water in a vacuum oven. The obtained composite films were transparent, colored, and capable of absorbing UV radiation. Improved mechanical properties were also obtained in relation to the nonfilled PVA films. These results demonstrate the onset of a new range of potential applications for layered hydroxide salts in the preparation of polymer composite multifunctional materials.

Urinary casts

MedlinePlus

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

Casting Technology.

ERIC Educational Resources Information Center

Wright, Michael D.; And Others

1992-01-01

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

Vacuum-Assisted Low-Temperature Synthesis of Reduced Graphene Oxide Thin-Film Electrodes for High-Performance Transparent and Flexible All-Solid-State Supercapacitors.

PubMed

Aytug, Tolga; Rager, Matthew S; Higgins, Wesley; Brown, Forrest G; Veith, Gabriel M; Rouleau, Christopher M; Wang, Hui; Hood, Zachary D; Mahurin, Shannon M; Mayes, Richard T; Joshi, Pooran C; Kuruganti, Teja

2018-04-04

Simple and easily integrated design of flexible and transparent electrode materials affixed to polymer-based substrates hold great promise to have a revolutionary impact on the functionality and performance of energy storage devices for many future consumer electronics. Among these applications are touch sensors, roll-up displays, photovoltaic cells, health monitors, wireless sensors, and wearable communication devices. Here, we report an environmentally friendly, simple, and versatile approach to produce optically transparent and mechanically flexible all-solid-state supercapacitor devices. These supercapacitors were constructed on tin-doped indium oxide coated polyethylene terephthalate substrates by intercalation of a polymer-based gel electrolyte between two reduced graphene oxide (rGO) thin-film electrodes. The rGO electrodes were fabricated simply by drop-casting of graphene oxide (GO) films, followed by a novel low-temperature (≤250 °C) vacuum-assisted annealing approach for the in situ reduction of GO to rGO. A trade-off between the optical transparency and electrochemical performance is determined by the concentration of the GO in the initial dispersion, whereby the highest capacitance (∼650 μF cm -2 ) occurs at a relatively lower optical transmittance (24%). Notably, the all-solid-state supercapacitors demonstrated excellent mechanical flexibility with a capacity retention rate above 90% under various bending angles and cycles. These attributes underscore the potential of the present approach to provide a path toward the realization of thin-film-based supercapacitors as flexible and transparent energy storage devices for a variety of practical applications.

Electronic gap sensor and method

DOEpatents

Williams, R.S.; King, E.L.; Campbell, S.L.

1991-08-06

Disclosed are an apparatus and method for regulating the gap between a casting nozzle and a casting wheel in which the gap between the casting nozzle and the casting wheel is monitored by means of at least one sensing element protruding from the face of the casting nozzle. The sensing element is preferably connected to a voltage source and the casting wheel grounded. When the sensing element contacts the casting wheel, an electric circuit is completed. The completion of the circuit can be registered by an indicator, and the presence or absence of a completed circuit indicates the relative position of the casting nozzle to the casting wheel. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces. 5 figures.

Electronic gap sensor and method

DOEpatents

Williams, Robert S.; King, Edward L.; Campbell, Steven L.

1991-01-01

An apparatus and method for regulating the gap between a casting nozzle and a casting wheel in which the gap between the casting nozzle and the casting wheel is monitored by means of at least one sensing element protruding from the face of the casting nozzle. The sensing element is preferably connected to a voltage source and the casting wheel grounded. When the sensing element contacts the casting wheel, an electric circuit is completed. The completion of the circuit can be registered by an indicator, and the presence or absence of a completed circuit indicates the relative position of the casting nozzle to the casting wheel. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces.

Method of casting articles of a bulk-solidifying amorphous alloy

DOEpatents

Lin, X.; Johnson, W.L.; Peker, A.

1998-08-25

A casting charge of a bulk-solidifying amorphous alloy is cast into a mold from a temperature greater than its crystallized melting temperature, and permitted to solidify to form an article. The oxygen content of the casting charge is limited to an operable level, as excessively high oxygen contents produce premature crystallization during the casting operation. During melting, the casting charge is preferably heated to a temperature above a threshold temperature to eliminate heterogeneous crystallization nucleation sites within the casting charge. The casting charge may be cast from above the threshold temperature, or it may be cooled to the casting temperature of more than the crystallized melting point but not more than the threshold temperature, optionally held at this temperature for a period of time, and thereafter cast. 8 figs.

Method of casting articles of a bulk-solidifying amorphous alloy

DOEpatents

Lin, Xianghong; Johnson, William L.; Peker, Atakan

1998-01-01

A casting charge of a bulk-solidifying amorphous alloy is cast into a mold from a temperature greater than its crystallized melting temperature, and permitted to solidify to form an article. The oxygen content of the casting charge is limited to an operable level, as excessively high oxygen contents produce premature crystallization during the casting operation. During melting, the casting charge is preferably heated to a temperature above a threshold temperature to eliminate heterogeneous crystallization nucleation sites within the casting charge. The casting charge may be cast from above the threshold temperature, or it may be cooled to the casting temperature of more than the crystallized melting point but not more than the threshold temperature, optionally held at this temperature for a period of time, and thereafter cast.

[Manufacture and clinical application of 215 IPS-Empress casting ceramic restorations].

PubMed

Zhao, Na; Zhou, Jian

2008-08-01

To explore the manufacture and clinical application of IPS-Empress casting ceramic restorations. The problems in manufacture and clinical operation of 215 casting ceramic restorations were analyzed. In 215 casting ceramic restorations, 12 (5.58%) casting ceramic restorations were affected by clinical design or application, 15 (6.98%) casting ceramic restorations were affected by some manufacture problems, and 14 (6.51%) casting ceramic restorations were affected by clinical try-in. Through 2-3 years' follow-up, the achievement ratio of 215 IPS-Empress casting ceramic restorations was 94.88%, and 11 casting ceramic restorations were affected by some problems. Beauty and simultaneous enamel wear are the characteristics of casting ceramic restorations. But because of its brittle, the indications should be strictly selected.

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

DOEpatents

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

2002-01-01

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

Applying network analysis and Nebula (neighbor-edges based and unbiased leverage algorithm) to ToxCast data.

PubMed

Ye, Hao; Luo, Heng; Ng, Hui Wen; Meehan, Joe; Ge, Weigong; Tong, Weida; Hong, Huixiao

2016-01-01

ToxCast data have been used to develop models for predicting in vivo toxicity. To predict the in vivo toxicity of a new chemical using a ToxCast data based model, its ToxCast bioactivity data are needed but not normally available. The capability of predicting ToxCast bioactivity data is necessary to fully utilize ToxCast data in the risk assessment of chemicals. We aimed to understand and elucidate the relationships between the chemicals and bioactivity data of the assays in ToxCast and to develop a network analysis based method for predicting ToxCast bioactivity data. We conducted modularity analysis on a quantitative network constructed from ToxCast data to explore the relationships between the assays and chemicals. We further developed Nebula (neighbor-edges based and unbiased leverage algorithm) for predicting ToxCast bioactivity data. Modularity analysis on the network constructed from ToxCast data yielded seven modules. Assays and chemicals in the seven modules were distinct. Leave-one-out cross-validation yielded a Q(2) of 0.5416, indicating ToxCast bioactivity data can be predicted by Nebula. Prediction domain analysis showed some types of ToxCast assay data could be more reliably predicted by Nebula than others. Network analysis is a promising approach to understand ToxCast data. Nebula is an effective algorithm for predicting ToxCast bioactivity data, helping fully utilize ToxCast data in the risk assessment of chemicals. Published by Elsevier Ltd.

Dimensional control of die castings

NASA Astrophysics Data System (ADS)

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 this study will contribute to enhancement of dimensional quality and lead time compression in the die casting industry, thus making it competitive with other net shape manufacturing processes.

Lower limb intracast pressures generated by different types of immobilisation casts.

PubMed

Chaudhury, Salma; Hazlerigg, Alexandra; Vusirikala, Anuhya; Nguyen, Joseph; Matthews, Stuart

2017-02-18

To determine if complete, split casts and backslabs [plaster of Paris (POP) and fiberglass] generate different intracast pressures and pain. Increased swelling within casts was modeled by a closed water system attached to an expandable bag placed directly under different types of casts applied to a healthy lower limb. Complete fiberglass and POP casts, split casts and backslabs were applied. Twenty-five milliliter aliquots of saline were injected into the system and the generated intracast pressures were measured using a sphygmomanometer. The subject was blinded to the pressure scores to avoid bias. All casts were applied to the same right limb on the same subject to avoid the effects of variations in anatomy or physiology on intracast pressures. Pain levels were evaluated using the Visual Analogue Score after each sequential saline injection. Each type of cast was reapplied four times and the measurements were repeated on four separate occasions. Sample sizes were determined by a pre-study 90% power calculation to detect a 20% difference in intracast pressures between cast groups. A significant difference between the various types of casts was noted when the saline volume was greater than 100 mL ( P = 0.009). The greatest intracast pressure was generated by complete fiberglass casts, which were significantly higher than complete POP casts or backslabs ( P = 0.018 and P = 0.008 respectively) at intracast saline volumes of 100 mL and higher. Backslabs produced a significantly lower intracast pressure compared to complete POP only once the saline volume within casts exceeded 225 mL ( P = 0.009). Intracast pressures were significantly lower in split casts ( P = 0.003). Split POP and fiberglass casts produced the lowest intracast pressures, even compared to backslabs ( P = 0.009). Complete fiberglass casts generated the highest pain levels at manometer pressures of 75 mmHg and greater ( P = 0.001). Split fiberglass casts had significantly reduced pain levels ( P = 0.001). In contrast, a split complete POP cast did not produce significantly reduced pain levels at pressures between 25-150 mmHg. There was no difference in pain generated by complete POP and backslabs at manometer pressures of 200 mmHg and lower. Fibreglass casts generate significantly higher intracast pressures and pain than POP casts. Split casts cause lower intracast pressures regardless of material, than complete casts and backslabs.

Riser Feeding Evaluation Method for Metal Castings Using Numerical Analysis

NASA Astrophysics Data System (ADS)

Ahmad, Nadiah

One of the design aspects that continues to create a challenge for casting designers is the optimum design of casting feeders (risers). As liquid metal solidifies, the metal shrinks and forms cavities inside the casting. In order to avoid shrinkage cavities, risers are added to the casting shape to supply additional molten metal when shrinkage occurs during solidification. The shrinkage cavities in the casting are compensated by controlling the cooling rate to promote directional solidification. This control can be achieved by designing the casting such that the cooling begins at the sections that are farthest away from the risers and ends at the risers. Therefore, the risers will solidify last and feed the casting with the molten metal. As a result, the shrinkage cavities formed during solidification are in the risers which are later removed from the casting. Since casting designers have to usually go through iterative processes of validating the casting designs which are very costly due to expensive simulation processes or manual trials and errors on actual casting processes, this study investigates more efficient methods that will help casting designers utilize their casting experiences systematically to develop good initial casting designs. The objective is to reduce the casting design method iterations; therefore, reducing the cost involved in that design processes. The aim of this research aims at finding a method that can help casting designers design effective risers used in sand casting process of aluminum-silicon alloys by utilizing the analysis of solidification simulation. The analysis focuses on studying the significance of pressure distribution of the liquid metal at the early stage of casting solidification, when heat transfer and convective fluid flow are taken into account in the solidification simulation. The mathematical model of casting solidification was solved using the finite volume method (FVM). This study focuses to improve our understanding of the feeding behavior in aluminum-silicon alloys and the effective feeding by considering the pressure gradient distribution of the molten metal at casting dendrite coherency point. For this study, we will identify the relationship between feeding efficiency, shrinkage behavior and how the change in riser size affects the pressure gradient in the casting. This understanding will be used to help in the design of effective risers.

Aluminum-Alloy-Matrix/Alumina-Reinforcement Composites

NASA Technical Reports Server (NTRS)

Kashalikar, Uday; Rozenoyer, Boris

2004-01-01

Isotropic composites of aluminum-alloy matrices reinforced with particulate alumina have been developed as lightweight, high-specific-strength, less-expensive alternatives to nickel-base and ferrous superalloys. These composites feature a specific gravity of about 3.45 grams per cubic centimeter and specific strengths of about 200 MPa/(grams per cubic centimeter). The room-temperature tensile strength is 100 ksi (689 MPa) and stiffness is 30 Msi (206 GPa). At 500 F (260 C), these composites have shown 80 percent retention in strength and 95 percent retention in stiffness. These materials also have excellent fatigue tolerance and tribological properties. They can be fabricated in net (or nearly net) sizes and shapes to make housings, pistons, valves, and ducts in turbomachinery, and to make structural components of such diverse systems as diesel engines, automotive brake systems, and power-generation, mining, and oil-drilling equipment. Separately, incorporation of these metal matrix composites within aluminum gravity castings for localized reinforcement has been demonstrated. A composite part of this type can be fabricated in a pressure infiltration casting process. The process begins with the placement of a mold with alumina particulate preform of net or nearly net size and shape in a crucible in a vacuum furnace. A charge of the alloy is placed in the crucible with the preform. The interior of the furnace is evacuated, then the furnace heaters are turned on to heat the alloy above its liquidus temperature. Next, the interior of the furnace is filled with argon gas at a pressure about 900 psi (approximately equal to 6.2 MPa) to force the molten alloy to infiltrate the preform. Once infiltrated, the entire contents of the crucible can be allowed to cool in place, and the composite part recovered from the mold.

Processing, physical metallurgy and creep of NiAl + Ta and NiAl + Nb alloys. Ph.D. Thesis. Final Contractor Report

NASA Technical Reports Server (NTRS)

Pathare, Viren M.

1988-01-01

Powder processed NiAl + Ta alloys containing 1, 2, and 4.5 at percent tantalum and NiAl + Nb alloys containing 1 and 2 at percent niobium were developed for improved creep properties. In addition, a cast alloy with 5 at percent tantalum was also studied. Hot extrusion parameters for processing alloys with 1 and 2 at percent of tantalum or niobium were designed. The NiAl + 4.5 at percent Ta alloy could be vacuum hot pressed successfully, even though it could not be extruded. All the phases in the multiphase alloys were identified and the phase transformations studied. The Ni2AlTa in NiAl + 4.5 at percent Ta alloy transforms into a liquid phase above 1700 K. Solutionizing and annealing below this temperature gives rise to a uniform distribution of fine second phase precipitates. Compressive creep properties were evaluated at 1300 K using constant load and constant velocity tests. In the higher strain rate region single phase NiAl + 1 at percent Ta and NiAl + 1 at percent Nb alloys exhibit a stress exponent of 5 characteristic of climb controlled dislocation creep. In slower strain rate regime diffusional creep becomes important. The two phase alloys containing 2 to 5 at percent Ta and 2 at percent Nb show considerable improvement over binary NiAl and single phase alloys. Loose dislocation networks and tangles stabilized by the precipitates were found in the as crept microstructure. The cast alloy which has larger grains and a distribution of fine precipitates shows the maximum improvement over binary NiAl.

The Role of Indian Caste Identity and Caste Inconsistent Norms on Status Representation

PubMed Central

Sankaran, Sindhuja; Sekerdej, Maciek; von Hecker, Ulrich

2017-01-01

The Indian caste system is a complex social structure wherein social roles like one’s profession became ‘hereditary,’ resulting in restricted social mobility and fixed status hierarchies. Furthermore, we argue that the inherent property of caste heightens group identification with one’s caste. Highly identified group members would protect the identity of the group in situations when group norms are violated. In this paper, we were interested in examining the consequence of caste norm violation and how an individual’s status is mentally represented. High caste norms are associated with moral values while the lower caste norms are associated with immorality. We predicted a ‘black sheep effect,’ that is, when high caste individuals’ group identity (caste norm violation condition) is threatened their salient high caste identity would increase, thereby resulting in devaluing the status of their fellow in-group member if the latter is perceived as perpetrator. We presented participants with a social conflict situation of a victim and a perpetrator that is ‘Caste norm consistent’ (Lower caste individual as a perpetrator and higher caste individual as a victim) and vice versa ‘Caste norm inconsistent’ condition (higher caste individual as perpetrator and lower caste individual as a victim). Then, participants had to choose from nine pictorial depictions representing the protagonists in the story on a vertical line, with varying degrees of status distance. Results showed evidence for the black sheep effect and, furthermore, revealed that no other identity (religious, national, and regional) resulted in devaluing the status of fellow in-group member. These results help us understand the ‘black sheep’ effect in the context of moral norms and status representation and are discussed in the framework of the Indian society. PMID:28408896

The Role of Indian Caste Identity and Caste Inconsistent Norms on Status Representation.

PubMed

Sankaran, Sindhuja; Sekerdej, Maciek; von Hecker, Ulrich

2017-01-01

The Indian caste system is a complex social structure wherein social roles like one's profession became 'hereditary,' resulting in restricted social mobility and fixed status hierarchies. Furthermore, we argue that the inherent property of caste heightens group identification with one's caste. Highly identified group members would protect the identity of the group in situations when group norms are violated. In this paper, we were interested in examining the consequence of caste norm violation and how an individual's status is mentally represented. High caste norms are associated with moral values while the lower caste norms are associated with immorality. We predicted a 'black sheep effect,' that is, when high caste individuals' group identity (caste norm violation condition) is threatened their salient high caste identity would increase, thereby resulting in devaluing the status of their fellow in-group member if the latter is perceived as perpetrator. We presented participants with a social conflict situation of a victim and a perpetrator that is ' Caste norm consistent' (Lower caste individual as a perpetrator and higher caste individual as a victim) and vice versa 'Caste norm inconsistent' condition (higher caste individual as perpetrator and lower caste individual as a victim). Then, participants had to choose from nine pictorial depictions representing the protagonists in the story on a vertical line, with varying degrees of status distance. Results showed evidence for the black sheep effect and, furthermore, revealed that no other identity (religious, national, and regional) resulted in devaluing the status of fellow in-group member. These results help us understand the 'black sheep' effect in the context of moral norms and status representation and are discussed in the framework of the Indian society.

Casting fine grained, fully dense, strong inorganic materials

DOE Office of Scientific and Technical Information (OSTI.GOV)

Brown, Sam W.; Spencer, Larry S.; Phillips, Michael R.

2015-11-24

Methods and apparatuses for casting inorganic materials are provided. The inorganic materials include metals, metal alloys, metal hydrides and other materials. Thermal control zones may be established to control the propagation of a freeze front through the casting. Agitation from a mechanical blade or ultrasonic energy may be used to reduce porosity and shrinkage in the casting. After solidification of the casting, the casting apparatus may be used to anneal the cast part.

[The surface roughness analysis of the titanium casting founding by a new titanium casting investment material].

PubMed

Liang, Qin-ye; Wu, Xia-yi; Lin, Xue-feng

2012-04-01

To investigate the surface roughness property of the titanium castings cast in a new investment for titanium casting. Six wax patterns (20 mm × 20 mm × 0.5 mm) were invested using two investments: three in a new titanium investment material and three in the control material (Rematitan Plus). Six titanium specimens were obtained by conventional casting. After casting, surface roughness of the specimens were evaluated with a surface profilometer. The surface roughness of the specimens cast in new titanium investment material was (1.72 ± 0.08) µm, which was much smaller than that from Rematitan Plus [(1.91 ± 0.15) µm, P < 0.05]. The surfaces of titanium cast using these two investment materials are both smooth enough to fulfill the demand of the titanium precision-casting for prosthodontic clinical use.

Marginal accuracy of nickel chromium copings fabricated by conventional and accelerated casting procedures, produced with ringless and metal ring investment procedures: A comparative in vitro study.

PubMed

Alex, Deepa; Shetty, Y Bharath; Miranda, Glynis Anita; Prabhu, M Bharath; Karkera, Reshma

2015-01-01

Conventional investing and casting techniques are time-consuming and usually requires 2-4 h for completion. Accelerated nonstandard, casting techniques have been reported to achieve similar quality results in significantly less time, namely, in 30-40 min. During casting, it is essential to achieve compensation for the shrinkage of solidifying alloy by investment expansion. The metal casting ring restricts the thermal expansion of investment because the thermal expansion of the ring is lesser than that of the investment. The use of casting ring was challenged with the introduction of the ringless technique. A total of 40 test samples of nickel chromium (Ni-Cr) cast copings were obtained from the patterns fabricated using inlay casting wax. The 20 wax patterns were invested using metal ring and 20 wax patterns were invested using the ringless investment system. Of both the groups, 10 samples underwent conventional casting, and the other 10 underwent accelerated casting. The patterns were casted using the induction casting technique. All the test samples of cast copings were evaluated for vertical marginal gaps at four points on the die employing a stereo optical microscope. The vertical marginal discrepancy data obtained were tabulated. Mean and standard deviations were obtained. Vertical discrepancies were analyzed using analysis of variance and Tukey honestly significantly different. The data obtained were found to be very highly significant (P < 0.001). Mean vertical gap was the maximum for Group II (53.64 μm) followed by Group IV (47.62 μm), Group I (44.83 μm) and Group III (35.35 μm). The Ni-Cr cast copings fabricated with the conventional casting using ringless investment system showed significantly better marginal fit than that of cast copings fabricated from conventional and accelerated casting with metal ring investment and accelerated casting using ringless investment since those copings had shown the least vertical marginal discrepancies among the four methods evaluated in this study.

Venous haemodynamics of Jet Impulse Technology within a lower limb fibreglass cast: a randomized controlled trial.

PubMed

Braithwaite, Irene; Mackintosh, Stephen; Buchanan, Samantha; Schwarzenlander, Kerstin; De Ruyter, Bernadette

2017-02-01

We investigated popliteal venous haemodynamics of the VenaJet Jet Impulse Technology system within a below-knee fibreglass cast. Randomized controlled trial. Twenty-four healthy participants aged 18-54 had both feet placed within the Jet Impulse Technology system and were randomised for one or other leg to be within a below-knee fibreglass cast. Pacific Radiology, Lower Hutt, Wellington. The primary outcome variable was peak systolic velocity (cm/s) compared between legs with and without the cast at 60 min (after 10 min Jet Impulse Technology activation), using a mixed linear model and a non-inferiority bound of 4.8 cm/s. Secondary outcome variables were the difference in peak systolic velocity between the casted limb and the non-casted limb at baseline and 40 min after casting, and the difference in mean flow velocity (cm/s), vein diameter (mm), and total volume flow (L/min) between the casted limb and the non-casted limb at baseline, 40 and 60 min. The mean (standard deviation) peak systolic velocity was 4.6(1.5), 4.8(1.1), 28.8(16.1), and 4.3(1.2), 4.8(1.4) and 29.3(19.0) cm/s at baseline, 40 and 60 min in the casted and non-casted leg, respectively. The difference (95% confidence interval) between cast and no-cast at 60 min was -0.8 (-6.5 to 4.9) cm/s, P  = 0.78. The peak systolic velocity, flow velocity and total volume flow at 40 min were not statistically significantly different from baseline for both casted and non-casted limb. In healthy volunteers, the popliteal venous haemodynamics of the Jet Impulse Technology system was similar between the legs with and without a below-knee fibreglass cast. In-cast Jet Impulse Technology may provide a non-pharmacological option for venous thromboembolism prophylaxis for lower-limb cast-immobility.

Improved Foundry Castings Utilizing CAD/CAM (Computer Aided Design/ Computer Aided Manufacture). Volume 1. Overview

DTIC Science & Technology

1988-06-30

casting. 68 Figure 1-9: Line printer representation of roll solidification. 69 Figure I1-1: Test casting model. 76 Figure 11-2: Division of test casting...writing new casting analysis and design routines. The new routines would take advantage of advanced criteria for predicting casting soundness and cast...properties and technical advances in computer hardware and software. 11 2. CONCLUSIONS UPCAST, a comprehensive software package, has been developed for

Method and apparatus for in-situ drying investigation and optimization of slurry drying methodology

DOEpatents

Armstrong, Beth L.; Daniel, Claus; Howe, Jane Y.; Kiggans, Jr, James O.; Sabau, Adrian S.; Wood, III, David L.; Kalnaus, Sergiy

2016-05-10

A method of drying casted slurries that includes calculating drying conditions from an experimental model for a cast slurry and forming a cast film. An infrared heating probe is positioned on one side of the casted slurry and a thermal probe is positioned on an opposing side of the casted slurry. The infrared heating probe may control the temperature of the casted slurry during drying. The casted slurry may be observed with an optical microscope, while applying the drying conditions from the experimental model. Observing the casted slurry includes detecting the incidence of micro-structural changes in the casted slurry during drying to determine if the drying conditions from the experimental model are optimal.

Genetic variation in South Indian castes: evidence from Y-chromosome, mitochondrial, and autosomal polymorphisms

PubMed Central

Watkins, WS; Thara, R; Mowry, BJ; Zhang, Y; Witherspoon, DJ; Tolpinrud, W; Bamshad, MJ; Tirupati, S; Padmavati, R; Smith, H; Nancarrow, D; Filippich, C; Jorde, LB

2008-01-01

Background Major population movements, social structure, and caste endogamy have influenced the genetic structure of Indian populations. An understanding of these influences is increasingly important as gene mapping and case-control studies are initiated in South Indian populations. Results We report new data on 155 individuals from four Tamil caste populations of South India and perform comparative analyses with caste populations from the neighboring state of Andhra Pradesh. Genetic differentiation among Tamil castes is low (RST = 0.96% for 45 autosomal short tandem repeat (STR) markers), reflecting a largely common origin. Nonetheless, caste- and continent-specific patterns are evident. For 32 lineage-defining Y-chromosome SNPs, Tamil castes show higher affinity to Europeans than to eastern Asians, and genetic distance estimates to the Europeans are ordered by caste rank. For 32 lineage-defining mitochondrial SNPs and hypervariable sequence (HVS) 1, Tamil castes have higher affinity to eastern Asians than to Europeans. For 45 autosomal STRs, upper and middle rank castes show higher affinity to Europeans than do lower rank castes from either Tamil Nadu or Andhra Pradesh. Local between-caste variation (Tamil Nadu RST = 0.96%, Andhra Pradesh RST = 0.77%) exceeds the estimate of variation between these geographically separated groups (RST = 0.12%). Low, but statistically significant, correlations between caste rank distance and genetic distance are demonstrated for Tamil castes using Y-chromosome, mtDNA, and autosomal data. Conclusion Genetic data from Y-chromosome, mtDNA, and autosomal STRs are in accord with historical accounts of northwest to southeast population movements in India. The influence of ancient and historical population movements and caste social structure can be detected and replicated in South Indian caste populations from two different geographic regions. PMID:19077280

Twin-belt continuous caster with containment and cooling of the exiting cast product for enabling high-speed casting of molten-center product

DOEpatents

Dykes, Charles D.; Daniel, Sabah S.; Wood, J. F. Barry

1990-02-20

In continuously casting molten metal into cast product by a twin-belt machine, it is desirable to achieve dramatic increases in speed (linear feet per minute) at which cast product exits the machine, particularly in installations where steel cast product is intended to feed a downstream regular rolling mill (as distinct from a planetary mill) operating in tandem with the twin-belt caster. Such high-speed casting produces product with a relatively thin shell and molten interior, and the shell tends to bulge outwardly due to metallostatic head pressure of the molten center. A number of cooperative features enable high-speed, twin-belt casting: (1) Each casting belt is slidably supported adjacent to the caster exit pulley for bulge control and enhanced cooling of cast product. (2) Lateral skew steering of each belt provides an effective increase in moving mold length plus a continuity of heat transfer not obtained with prior art belt steering apparatus. (3) The exiting slab is contained and supported downstream from the casting machine to prevent bulging of the shell of the cast product, and (4) spray cooling is incorporated in the exit containment apparatus for secondary cooling of cast product.

Marginal Accuracy of Castings Fabricated with Ringless Casting Investment System and Metal Ring Casting Investment System: A Comparative Study.

PubMed

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.

46 CFR 56.60-10 - Cast iron and malleable iron.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 2 2010-10-01 2010-10-01 false Cast iron and malleable iron. 56.60-10 Section 56.60-10... APPURTENANCES Materials § 56.60-10 Cast iron and malleable iron. (a) The low ductility of cast iron and... avoided. Cast iron and malleable iron components shall not be used at temperatures above 450 °F. Cast iron...

Noise Reduction to Reduce Patient Anxiety During Cast Removal: Can We Decrease Patient Anxiety With Cast Removal by Wearing Noise Reduction Headphones During Cast Saw Use?

PubMed

Mahan, Susan T; Harris, Marie S; Lierhaus, Anneliese M; Miller, Patricia E; DiFazio, Rachel L

Noise reduction headphones decrease the sound during cast removal. Their effectiveness in decreasing anxiety has not been studied. Compare pediatric patients' anxiety levels during cast removal with and without utilization of noise reduction headphones combined with use of a personal electronic device. Quality improvement project. Patients randomly assigned to noise reduction headphone group or standard care group during cast removal. Faces, Legs, Activity, Cry, and Consolability Scale and heart rate were evaluated prior to, during, and after cast removal. Data were compared across groups. Fifty patients were included; 25 per group. No difference detected between the 2 groups in Faces, Legs, Activity, Cry, and Consolability Scale score prior to (p = .05) or after cast removal (p = .30). During cast removal, the headphone group had lower FLACC Scale scores (p = .03). Baseline heart rate was lower in the headphone group prior to (p = .02) and after (p = .005) cast removal with no difference during cast removal (p = .24). Utilizing noise reduction headphones and a personal electronic device during the cast removal process decreases patient anxiety.

[Variables effecting casting accuracy of quick heating casting investments].

PubMed

Takahashi, H; Nakamura, H; Iwasaki, N; Morita, N; Habu, N; Nishimura, F

1994-06-01

Recently, several new products of investments for "quick heating" have been put on the Japanese market. The total casting procedure time for this quick heating method involves only one hour; 30-minutes waiting after the start of mixing before placing the mold directly into the 700 degrees C furnace and 30-minutes heating in the furnace. The purpose of this study was to evaluate two variables effecting casting accuracy using these new investments. The effect of thickness of the casting liner inside the casting ring and the effect of waiting time before placing the mold into the 700 degrees C furnace were evaluated. A stainless-steel die with a convergence angle of 8 degrees was employed. Marginal discrepancies of the crown between the wax patterns and castings were measured. The size of the cast crown became larger when the thickness of the ring liner was thick and when the waiting time before placing the mold into the furnace was long. These results suggest that these new investments have the advantage of providing sound castings using short-time casting procedures. However, it is necessary to pay careful attention to the casting conditions for obtaining reproducible castings.

Distal limb cast sores in horses: risk factors and early detection using thermography.

PubMed

Levet, T; Martens, A; Devisscher, L; Duchateau, L; Bogaert, L; Vlaminck, L

2009-01-01

There is a lack of evidence-based data on the prevalence, outcome and risk factors of distal limb cast sores, and no objective tool has been described for the early detection of cast sores. To investigate the prevalence, location, outcome and risk factors of cast sores after application of a distal limb cast and to determine whether static thermography of the cast is a valuable tool for the assessment of sores. A prospective study was conducted on horses treated with a distal limb cast. At each cast removal, cast sores were graded as superficial sores (SS), deep dermal sores (DS) or full thickness skin ulcerations (FS). In several cases, a thermographic evaluation of the cast was performed immediately prior to removal and differences in temperature (AT) between the coolest point of the cast and 2 cast regions predisposed for sore development (dorsoproximal mc/mtIII and palmar/plantar fetlock) were calculated. Mean +/- s.d. total casting time of 70 horses was 31 +/- 18 days. Overall, 57 legs (81%) developed at least SS. Twenty-four legs (34%) ultimately developed DS and one horse had an FS. Multivariable analysis showed that the severity of sores was positively associated with increasing age (OR: 1.111, P = 0.028), a normal (vs. swollen) limb (OR: 3387, P = 0.023) and an increase in total casting time (OR per week: 1.363, P = 0.002). The thermographic evaluation (35 casts) revealed that the severity of sores was positively associated with increasing deltaT (OR: 2.100, P = 0.0005). The optimal cut-off values for the presence of SS and DS were set at, respectively, deltaT = 23 and 43 degrees C. Distal limb cast is a safe coaptation technique with increasing risk of developing sores with time. Thermography is a valuable and rapid clinical tool to monitor the development of cast sores.

Energy Consumption of Die Casting Operations

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jerald Brevick; clark Mount-Campbell; Carroll Mobley

2004-03-15

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

Venous haemodynamics of Jet Impulse Technology within a lower limb fibreglass cast: a randomized controlled trial

PubMed Central

Mackintosh, Stephen; Buchanan, Samantha; Schwarzenlander, Kerstin; De Ruyter, Bernadette

2017-01-01

Objectives We investigated popliteal venous haemodynamics of the VenaJet Jet Impulse Technology system within a below-knee fibreglass cast. Design Randomized controlled trial. Participants Twenty-four healthy participants aged 18–54 had both feet placed within the Jet Impulse Technology system and were randomised for one or other leg to be within a below-knee fibreglass cast. Setting Pacific Radiology, Lower Hutt, Wellington Main outcome measures The primary outcome variable was peak systolic velocity (cm/s) compared between legs with and without the cast at 60 min (after 10 min Jet Impulse Technology activation), using a mixed linear model and a non-inferiority bound of 4.8 cm/s. Secondary outcome variables were the difference in peak systolic velocity between the casted limb and the non-casted limb at baseline and 40 min after casting, and the difference in mean flow velocity (cm/s), vein diameter (mm), and total volume flow (L/min) between the casted limb and the non-casted limb at baseline, 40 and 60 min. Results The mean (standard deviation) peak systolic velocity was 4.6(1.5), 4.8(1.1), 28.8(16.1), and 4.3(1.2), 4.8(1.4) and 29.3(19.0) cm/s at baseline, 40 and 60 min in the casted and non-casted leg, respectively. The difference (95% confidence interval) between cast and no-cast at 60 min was −0.8 (−6.5 to 4.9) cm/s, P = 0.78. The peak systolic velocity, flow velocity and total volume flow at 40 min were not statistically significantly different from baseline for both casted and non-casted limb. Conclusion In healthy volunteers, the popliteal venous haemodynamics of the Jet Impulse Technology system was similar between the legs with and without a below-knee fibreglass cast. In-cast Jet Impulse Technology may provide a non-pharmacological option for venous thromboembolism prophylaxis for lower-limb cast-immobility. PMID:28203384

Marginal accuracy of nickel chromium copings fabricated by conventional and accelerated casting procedures, produced with ringless and metal ring investment procedures: A comparative in vitro study

PubMed Central

Alex, Deepa; Shetty, Y. Bharath; Miranda, Glynis Anita; Prabhu, M. Bharath; Karkera, Reshma

2015-01-01

Background: Conventional investing and casting techniques are time-consuming and usually requires 2–4 h for completion. Accelerated nonstandard, casting techniques have been reported to achieve similar quality results in significantly less time, namely, in 30–40 min. During casting, it is essential to achieve compensation for the shrinkage of solidifying alloy by investment expansion. The metal casting ring restricts the thermal expansion of investment because the thermal expansion of the ring is lesser than that of the investment. The use of casting ring was challenged with the introduction of the ringless technique. Materials and Methods: A total of 40 test samples of nickel chromium (Ni-Cr) cast copings were obtained from the patterns fabricated using inlay casting wax. The 20 wax patterns were invested using metal ring and 20 wax patterns were invested using the ringless investment system. Of both the groups, 10 samples underwent conventional casting, and the other 10 underwent accelerated casting. The patterns were casted using the induction casting technique. All the test samples of cast copings were evaluated for vertical marginal gaps at four points on the die employing a stereo optical microscope. Results: The vertical marginal discrepancy data obtained were tabulated. Mean and standard deviations were obtained. Vertical discrepancies were analyzed using analysis of variance and Tukey honestly significantly different. The data obtained were found to be very highly significant (P < 0.001). Mean vertical gap was the maximum for Group II (53.64 μm) followed by Group IV (47.62 μm), Group I (44.83 μm) and Group III (35.35 μm). Conclusion: The Ni-Cr cast copings fabricated with the conventional casting using ringless investment system showed significantly better marginal fit than that of cast copings fabricated from conventional and accelerated casting with metal ring investment and accelerated casting using ringless investment since those copings had shown the least vertical marginal discrepancies among the four methods evaluated in this study. PMID:26929488

Factors contributing to the temperature beneath plaster or fiberglass cast material

PubMed Central

Hutchinson, Michael J; Hutchinson, Mark R

2008-01-01

Background Most cast materials mature and harden via an exothermic reaction. Although rare, thermal injuries secondary to casting can occur. The purpose of this study was to evaluate factors that contribute to the elevated temperature beneath a cast and, more specifically, evaluate the differences of modern casting materials including fiberglass and prefabricated splints. Methods The temperature beneath various types (plaster, fiberglass, and fiberglass splints), brands, and thickness of cast material were measured after they were applied over thermometer which was on the surface of a single diameter and thickness PVC tube. A single layer of cotton stockinette with variable layers and types of cast padding were placed prior to application of the cast. Serial temperature measurements were made as the cast matured and reached peak temperature. Time to peak, duration of peak, and peak temperature were noted. Additional tests included varying the dip water temperature and assessing external insulating factors. Ambient temperature, ambient humidity and dip water freshness were controlled. Results Outcomes revealed that material type, cast thickness, and dip water temperature played key roles regarding the temperature beneath the cast. Faster setting plasters achieved peak temperature quicker and at a higher level than slower setting plasters. Thicker fiberglass and plaster casts led to greater peak temperature levels. Likewise increasing dip-water temperature led to elevated temperatures. The thickness and type of cast padding had less of an effect for all materials. With a definition of thermal injury risk of skin injury being greater than 49 degrees Celsius, we found that thick casts of extra fast setting plaster consistently approached dangerous levels (greater than 49 degrees for an extended period). Indeed a cast of extra-fast setting plaster, 20 layers thick, placed on a pillow during maturation maintained temperatures over 50 degrees of Celsius for over 20 minutes. Conclusion Clinicians should be cautious when applying thick casts with warm dip water. Fast setting plasters have increased risk of thermal injury while brand does not appear to play a significant role. Prefabricated fiberglass splints appear to be safer than circumferential casts. The greatest risk of thermal injury occurs when thick casts are allowed to mature while resting on pillow. PMID:18298851

Non-rigid Reconstruction of Casting Process with Temperature Feature

NASA Astrophysics Data System (ADS)

Lin, Jinhua; Wang, Yanjie; Li, Xin; Wang, Ying; Wang, Lu

2017-09-01

Off-line reconstruction of rigid scene has made a great progress in the past decade. However, the on-line reconstruction of non-rigid scene is still a very challenging task. The casting process is a non-rigid reconstruction problem, it is a high-dynamic molding process lacking of geometric features. In order to reconstruct the casting process robustly, an on-line fusion strategy is proposed for dynamic reconstruction of casting process. Firstly, the geometric and flowing feature of casting are parameterized in manner of TSDF (truncated signed distance field) which is a volumetric block, parameterized casting guarantees real-time tracking and optimal deformation of casting process. Secondly, data structure of the volume grid is extended to have temperature value, the temperature interpolation function is build to generate the temperature of each voxel. This data structure allows for dynamic tracking of temperature of casting during deformation stages. Then, the sparse RGB features is extracted from casting scene to search correspondence between geometric representation and depth constraint. The extracted color data guarantees robust tracking of flowing motion of casting. Finally, the optimal deformation of the target space is transformed into a nonlinear regular variational optimization problem. This optimization step achieves smooth and optimal deformation of casting process. The experimental results show that the proposed method can reconstruct the casting process robustly and reduce drift in the process of non-rigid reconstruction of casting.

Characterization of Ni-Cr alloys using different casting techniques and molds.

PubMed

Chen, Wen-Cheng; Teng, Fu-Yuan; Hung, Chun-Cheng

2014-02-01

This study differentiated the mechanical properties of nickel-chromium (Ni-Cr) alloys under various casting techniques (different casting molds and casting atmospheres). These techniques were sampled by a sand mold using a centrifugal machine in ambient air (group I) and electromagnetic induction in an automatic argon castimatic casting machine (group II). The specimen casting used a graphite mold by a castimatic casting machine (group III). The characteristics of the Ni-Cr alloys, yield and ultimate tensile strength, bending modulus, microhardness, diffraction phase, grindability, ability to spring back, as well as ground microstructure and pattern under different casting conditions were evaluated. The group III specimens exhibited the highest values in terms of strength, modulus, hardness, and grindability at a grind rate of 500 rpm. Moreover, group III alloys exhibited smaller grain sizes, higher ability to spring back, and greater ductility than those casted by sand investment (groups I and II). The main factor, "casting mold," significantly influenced all mechanical properties. The graphite mold casting of the Ni-Cr dental alloys in a controlled atmosphere argon casting system provided an excellent combination of high mechanical properties and good ability to spring back, and preserved the ductile properties for application in Ni-Cr porcelain-fused system. The results can offer recommendations to assist a prosthetic technician in selecting the appropriate casting techniques to obtain the desired alloy properties. Copyright © 2013 Elsevier B.V. All rights reserved.

40 CFR 464.30 - Applicability; description of the ferrous casting subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... ferrous casting subcategory. 464.30 Section 464.30 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Ferrous Casting Subcategory § 464.30 Applicability; description of the ferrous casting subcategory. The...

Polymer quenched prealloyed metal powder

DOEpatents

Hajaligol, Mohammad R.; Fleischhauer, Grier; German, Randall M.

2001-01-01

A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3 % Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

Method of manufacturing aluminide sheet by thermomechanical processing of aluminide powders

DOEpatents

Hajaligol, Mohammad R.; Scorey, Clive; Sikka, Vinod K.; Deevi, Seetharama C.; Fleishhauer, Grier; Lilly, Jr., A. Clifton; German, Randall M.

2003-12-09

A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3% Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

Thermomechanical processing of plasma sprayed intermetallic sheets

DOEpatents

Hajaligol, Mohammad R.; Scorey, Clive; Sikka, Vinod K.; Deevi, Seetharama C.; Fleischhauer, Grier; Lilly, Jr., A. Clifton; German, Randall M.

2001-01-01

A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3% Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

Method of manufacturing aluminide sheet by thermomechanical processing of aluminide powders

DOEpatents

Hajaligol, Mohammad R.; Scorey, Clive; Sikka, Vinod K.; Deevi, Seetharama C.; Fleischhauer, Grier; Lilly, Jr., A. Clifton; German, Randall M.

2000-01-01

A powder metallurgical process of preparing a sheet from a powder having an intermetallic alloy composition such as an iron, nickel or titanium aluminide. The sheet can be manufactured into electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 4 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.0.05% Zr.ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Ni, .ltoreq.0.75% C, .ltoreq.0.1% B, .ltoreq.1% submicron oxide particles and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1% rare earth metal, and/or .ltoreq.3% Cu. The process includes forming a non-densified metal sheet by consolidating a powder having an intermetallic alloy composition such as by roll compaction, tape casting or plasma spraying, forming a cold rolled sheet by cold rolling the non-densified metal sheet so as to increase the density and reduce the thickness thereof and annealing the cold rolled sheet. The powder can be a water, polymer or gas atomized powder which is subjecting to sieving and/or blending with a binder prior to the consolidation step. After the consolidation step, the sheet can be partially sintered. The cold rolling and/or annealing steps can be repeated to achieve the desired sheet thickness and properties. The annealing can be carried out in a vacuum furnace with a vacuum or inert atmosphere. During final annealing, the cold rolled sheet recrystallizes to an average grain size of about 10 to 30 .mu.m. Final stress relief annealing can be carried out in the B2 phase temperature range.

Separating the Role of Protein Restraints and Local Metal-Site Interaction Chemistry in the Thermodynamics of a Zinc Finger Protein

PubMed Central

Dixit, Purushottam D.; Asthagiri, D.

2011-01-01

We express the effective Hamiltonian of an ion-binding site in a protein as a combination of the Hamiltonian of the ion-bound site in vacuum and the restraints of the protein on the site. The protein restraints are described by the quadratic elastic network model. The Hamiltonian of the ion-bound site in vacuum is approximated as a generalized Hessian around the minimum energy configuration. The resultant of the two quadratic Hamiltonians is cast into a pure quadratic form. In the canonical ensemble, the quadratic nature of the resultant Hamiltonian allows us to express analytically the excess free energy, enthalpy, and entropy of ion binding to the protein. The analytical expressions allow us to separate the roles of the dynamic restraints imposed by the protein on the binding site and the temperature-independent chemical effects in metal-ligand coordination. For the consensus zinc-finger peptide, relative to the aqueous phase, the calculated free energy of exchanging Zn2+ with Fe2+, Co2+, Ni2+, and Cd2+ are in agreement with experiments. The predicted excess enthalpy of ion exchange between Zn2+ and Co2+ also agrees with the available experimental estimate. The free energy of applying the protein restraints reveals that relative to Zn2+, the Co2+, and Cd2+-site clusters are more destabilized by the protein restraints. This leads to an experimentally testable hypothesis that a tetrahedral metal binding site with minimal protein restraints will be less selective for Zn2+ over Co2+ and Cd2+ compared to a zinc finger peptide. No appreciable change is expected for Fe2+ and Ni2+. The framework presented here may prove useful in protein engineering to tune metal selectivity. PMID:21943427

Microstructural Evolution in Intensively Melt Sheared Direct Chill Cast Al-Alloys

NASA Astrophysics Data System (ADS)

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.

Driving with a short arm cast in a simulator.

PubMed

Mansour, Damian; Mansour, Kristin Gotaas; Kenny, Benjamin William; Attia, John; Meads, Bryce

2015-12-01

To test the ability to steer in a driving simulator in subjects with a short arm cast. 17 men and 13 women aged 23 to 67 (mean, 37) years who had a valid driver's licence were randomised to the cast-first group (n=16; 7 had the cast on the dominant arm) or the cast-second group (n=14; 8 had the cast on the dominant arm) and drove in a simulator. A short arm plaster-of-Paris cast was applied in a neutral position, allowing free movement of the metacarpophalangeal joints, thumb, and elbow joint. Outcome measures included the number of driving off track instances, the number of crashes, the lap time, and the effect of hand dominance on these parameters. Subjects were asked whether the cast had impeded their steering ability. Subjects with or without a cast were comparable in terms of the number of driving off track instances, number of crashes, and lap time. Compared with no cast, the odds ratio (OR) of a subject in a cast driving off the track was 1.02 (p=0.921) and having a crash was 0.79 (p=0.047). All subjects were 1.23 times more likely to drive off the track in their first lap (OR=2.66, p=0.019). The mean lap time decreased for each consecutive lap from the 2nd to 5th laps. Subjects driving with a cast on the dominant or non-dominant arm were comparable. 26 out of the 30 participants considered that the plaster cast impeded their steering ability. Compared with no cast, driving with a short arm cast did not significantly decrease steering ability in a driving simulator.

Quiet breathing in hindlimb casted mice.

PubMed

Receno, Candace N; Roffo, Katelynn E; Mickey, Marisa C; DeRuisseau, Keith C; DeRuisseau, Lara R

2018-06-07

The hindlimb casting model was developed to study skeletal muscle reloading following a period of unloading. It is unknown if ventilation parameters of mice are affected by the casting model. We tested the hypothesis that hindlimb casted mice have similar ventilatory patterns compared to mice with the casts removed. Male CD-1 mice underwent 14 days of hindlimb immobilization via plaster casting. Breathing parameters were obtained utilizing unrestrained barometric plethysmography (UBP). Breathing traces were analyzed with Ponemah software for breathing frequency, tidal volume (TV), and minute ventilation (MV). Frequency, TV and MV did not show any differences in quiet breathing patterns during or post-casting in mice. Thus, the hindlimb casting model does not complicate breathing during and after casting and should not interfere with the unloading and reloading of skeletal muscle. Copyright © 2018 Elsevier B.V. All rights reserved.

40 CFR 464.10 - Applicability; description of the aluminum casting subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... aluminum casting subcategory. 464.10 Section 464.10 Protection of Environment ENVIRONMENTAL PROTECTION... Aluminum Casting Subcategory § 464.10 Applicability; description of the aluminum casting subcategory. The... introduction of pollutants into publicly owned treatment works resulting from aluminum casting operations as...

40 CFR 464.20 - Applicability; description of the copper casting subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... copper casting subcategory. 464.20 Section 464.20 Protection of Environment ENVIRONMENTAL PROTECTION... Copper Casting Subcategory § 464.20 Applicability; description of the copper casting subcategory. The... introduction of pollutants into publicly owned treatment works resulting from copper casting operations as...

40 CFR 464.20 - Applicability; description of the copper casting subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... copper casting subcategory. 464.20 Section 464.20 Protection of Environment ENVIRONMENTAL PROTECTION... Copper Casting Subcategory § 464.20 Applicability; description of the copper casting subcategory. The... introduction of pollutants into publicly owned treatment works resulting from copper casting operations as...

Method of reducing the green density of a slip cast article

DOEpatents

Mangels, John A.; Dickie, Ray A.

1985-01-01

The method disclosed in this specification is one of reducing the green density of an article cast in a slip casting operation. The article is cast from a casting slip containing silicon metal particles, yttrium containing particles, and a small amount of a fluoride salt which is effective to suppress flocculation of the silicon metal particles by y.sup.+3 ions derived from the yttrium containing particles. The method is characterized by the following step. A small amount of compound which produces a cation which will partly flocculate the particles of silicon metal is added to the casting slip. The small amount of this compound is added so that when the casting slip is slip cast into a casting mold, the partly flocculated particles of silicon will interrupt an otherwise orderly packing of the particles of silicon and particles of yttrium. In this manner, the green density of the slip cast article is reduced and the article may be more easily nitrided.

Management of Intolerance to Casting the Upper Extremities in Claustrophobic Patients

PubMed Central

Nagura, Issei; Kanatani, Takako; Sumi, Masatoshi; Inui, Atsuyuki; Mifune, Yutaka; Kokubu, Takeshi; Kurosaka, Masahiro

2014-01-01

Introduction. Some patients showed unusual responses to the immobilization without any objective findings with casts in upper extremities. We hypothesized their that intolerance with excessive anxiety to casts is due to claustrophobia triggered by cast immobilization. The aim of this study is to analyze the relevance of cast immobilization to the feeling of claustrophobia and discover how to handle them. Methods. There were nine patients who showed the caustrophobic symptoms with their casts. They were assesed whether they were aware of their claustrophobis themselves. Further we investigated the alternative immobilization to casts. Results. Seven out of nine cases that were aware of their claustrophobic tendencies either were given removable splints initially or had the casts converted to removable splints when they exhibited symptoms. The two patients who were unaware of their latent claustrophobic tendencies were identified when they showed similar claustrophobic symptoms to the previous patients soon after short arm cast application. We replaced the casts with removable splints. This resolved the issue in all cases. Conclusions. We should be aware of the claustrophobia if patients showed unusual responses to the immobilization without any objective findings with casts in upper extremities, where removal splint is practical alternative to cast to continue the treatment successfully. PMID:25379544

AMCC casting development, volume 2

NASA Technical Reports Server (NTRS)

1995-01-01

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

Optimization to Develop Multiple Response Microstructure and Hardness of Ductile Iron Casting by using GRA

NASA Astrophysics Data System (ADS)

Kabnure, Bahubali Bhupal; Shinde, Vasudev Dhondiram; Kolhapure, Rakesh Ramchandra

2018-05-01

Ductile irons are important engineering materials because of its high strength to weight ratio and castability. The ductile iron castings are used widely for automobile applications due to their wide spectrum of property range. Weight reduction is important in automobile to improve its fuel efficiency which can be achieved by thinning down the casting sections without altering its functionality. Generally, automobile castings are having varying section thickness. Varying thickness castings offers different cooling rates while solidification of the casting. The solidification cooling rate decides the final microstructure of the cast components. Cooling rate was found to affect directly the amount of pearlite and ultimately the as cast properties in varying thickness ductile iron castings. In view of this, the automobile impeller casting is selected for study in the present work as it consists of varying section thickness in which small sections are connected to central hub. The casting solidification simulations were performed and analyzed. The solidification cooling rates were analyzed further to correlate the experimental processing parameters. The samples from poured castings were analyzed for microstructure and hardness at different section thickness. Multiple response optimization of microstructure and hardness was carried out by combined Taguchi and Grey Relational Analysis (GRA). Contribution of input variables on the output variables is attained using ANOVA.

Modelling the Cast Component Weight in Hot Chamber Die Casting using Combined Taguchi and Buckingham's π Approach

NASA Astrophysics Data System (ADS)

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.

41. PHOTOGRAPHY OF BLUE PRINT (MINNEAPOLIS CITY ENGINEER) END AND ...

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

41. PHOTOGRAPHY OF BLUE PRINT (MINNEAPOLIS CITY ENGINEER) END AND CENTRE CASTING OF CAST STEEL, MASONRY CASTING OF CAST IRON CASTING, FOR MINNEAPOLIS STEEL ARCH (4 x 5 negative) - Steel Arch Bridge, Hennepin Avenue spanning west channel of Mississippi River, Minneapolis, Hennepin County, MN

Basic Casting from A to Z. Student's Instruction Booklet.

ERIC Educational Resources Information Center

Zebco, Tulsa, OK.

A profusely illustrated student instruction booklet contains step-by-step directions and diagrams for learning four basic casting techniques. Separate sections cover basic spin-casting, spinning, bait-casting, and fly-casting. Each section details recommended equipment (reel, rod, line, plug, tackle, lures, leaders, flies), describes specific…

Genetic evidence on the origins of Indian caste populations.

PubMed

Bamshad, M; Kivisild, T; Watkins, W S; Dixon, M E; Ricker, C E; Rao, B B; Naidu, J M; Prasad, B V; Reddy, P G; Rasanayagam, A; Papiha, S S; Villems, R; Redd, A J; Hammer, M F; Nguyen, S V; Carroll, M L; Batzer, M A; Jorde, L B

2001-06-01

The origins and affinities of the approximately 1 billion people living on the subcontinent of India have long been contested. This is owing, in part, to the many different waves of immigrants that have influenced the genetic structure of India. In the most recent of these waves, Indo-European-speaking people from West Eurasia entered India from the Northwest and diffused throughout the subcontinent. They purportedly admixed with or displaced indigenous Dravidic-speaking populations. Subsequently they may have established the Hindu caste system and placed themselves primarily in castes of higher rank. To explore the impact of West Eurasians on contemporary Indian caste populations, we compared mtDNA (400 bp of hypervariable region 1 and 14 restriction site polymorphisms) and Y-chromosome (20 biallelic polymorphisms and 5 short tandem repeats) variation in approximately 265 males from eight castes of different rank to approximately 750 Africans, Asians, Europeans, and other Indians. For maternally inherited mtDNA, each caste is most similar to Asians. However, 20%-30% of Indian mtDNA haplotypes belong to West Eurasian haplogroups, and the frequency of these haplotypes is proportional to caste rank, the highest frequency of West Eurasian haplotypes being found in the upper castes. In contrast, for paternally inherited Y-chromosome variation each caste is more similar to Europeans than to Asians. Moreover, the affinity to Europeans is proportionate to caste rank, the upper castes being most similar to Europeans, particularly East Europeans. These findings are consistent with greater West Eurasian male admixture with castes of higher rank. Nevertheless, the mitochondrial genome and the Y chromosome each represents only a single haploid locus and is more susceptible to large stochastic variation, bottlenecks, and selective sweeps. Thus, to increase the power of our analysis, we assayed 40 independent, biparentally inherited autosomal loci (1 LINE-1 and 39 Alu elements) in all of the caste and continental populations (approximately 600 individuals). Analysis of these data demonstrated that the upper castes have a higher affinity to Europeans than to Asians, and the upper castes are significantly more similar to Europeans than are the lower castes. Collectively, all five datasets show a trend toward upper castes being more similar to Europeans, whereas lower castes are more similar to Asians. We conclude that Indian castes are most likely to be of proto-Asian origin with West Eurasian admixture resulting in rank-related and sex-specific differences in the genetic affinities of castes to Asians and Europeans.

Genetic Evidence on the Origins of Indian Caste Populations

PubMed Central

Bamshad, Michael; Kivisild, Toomas; Watkins, W. Scott; Dixon, Mary E.; Ricker, Chris E.; Rao, Baskara B.; Naidu, J. Mastan; Prasad, B.V. Ravi; Reddy, P. Govinda; Rasanayagam, Arani; Papiha, Surinder S.; Villems, Richard; Redd, Alan J.; Hammer, Michael F.; Nguyen, Son V.; Carroll, Marion L.; Batzer, Mark A.; Jorde, Lynn B.

2001-01-01

The origins and affinities of the ∼1 billion people living on the subcontinent of India have long been contested. This is owing, in part, to the many different waves of immigrants that have influenced the genetic structure of India. In the most recent of these waves, Indo-European-speaking people from West Eurasia entered India from the Northwest and diffused throughout the subcontinent. They purportedly admixed with or displaced indigenous Dravidic-speaking populations. Subsequently they may have established the Hindu caste system and placed themselves primarily in castes of higher rank. To explore the impact of West Eurasians on contemporary Indian caste populations, we compared mtDNA (400 bp of hypervariable region 1 and 14 restriction site polymorphisms) and Y-chromosome (20 biallelic polymorphisms and 5 short tandem repeats) variation in ∼265 males from eight castes of different rank to ∼750 Africans, Asians, Europeans, and other Indians. For maternally inherited mtDNA, each caste is most similar to Asians. However, 20%–30% of Indian mtDNA haplotypes belong to West Eurasian haplogroups, and the frequency of these haplotypes is proportional to caste rank, the highest frequency of West Eurasian haplotypes being found in the upper castes. In contrast, for paternally inherited Y-chromosome variation each caste is more similar to Europeans than to Asians. Moreover, the affinity to Europeans is proportionate to caste rank, the upper castes being most similar to Europeans, particularly East Europeans. These findings are consistent with greater West Eurasian male admixture with castes of higher rank. Nevertheless, the mitochondrial genome and the Y chromosome each represents only a single haploid locus and is more susceptible to large stochastic variation, bottlenecks, and selective sweeps. Thus, to increase the power of our analysis, we assayed 40 independent, biparentally inherited autosomal loci (1 LINE-1 and 39 Alu elements) in all of the caste and continental populations (∼600 individuals). Analysis of these data demonstrated that the upper castes have a higher affinity to Europeans than to Asians, and the upper castes are significantly more similar to Europeans than are the lower castes. Collectively, all five datasets show a trend toward upper castes being more similar to Europeans, whereas lower castes are more similar to Asians. We conclude that Indian castes are most likely to be of proto-Asian origin with West Eurasian admixture resulting in rank-related and sex-specific differences in the genetic affinities of castes to Asians and Europeans. PMID:11381027

Intrinsic evolution of novel (Nd, MM)2Fe14B-system magnetic flakes

NASA Astrophysics Data System (ADS)

Yu, Xiaoqiang; Zhu, Minggang; Liu, Weiqiang; Li, Yanfeng; Zhang, Jiuxing; Yue, Ming; Li, Wei

2018-01-01

The Nd-substituted (Nd x MM1- x )-Fe-B strip-casting flakes were prepared by induction melting in the vacuum furnace and then subsequently by strip-casting technology. The microstructure and magnetic properties of (Nd x MM1- x )-Fe-B alloys are related to the Nd substitution. 2:14:1 main phases and minor impure phases coexist in the MM-Fe-B flake. For example, La2O3 and CeFe2 impure phases are obviously detected in the x = 0 specimen. As an increase of the Ce concentration is inversely accompanied with the decrease of the Nd content ( x) in (Nd x MM1- x )2Fe14B main phases (0 ≤ x ≤ 1), XRD analysis shows that the overall diffraction peaks of the main phases shift to right domestically because of smaller radius Ce4+. The melting point, spin reorientation phase transition temperature, Curie temperature, magneto-crystalline anisotropy field (at 300 K), and the magnetization ( M 9T) for MM-Fe-B/(Nd0.4MM0.6)-Fe-B/(Nd0.7MM0.3)-Fe-B/Nd-Fe-B strip-casting alloys are 1376.15/1414.15/1439.15/1458.15 K, 74/113/124/135 K, 493.2/538.4/559.7/582.3 K, 48/55.2/64.4/70.1 kOe and 136.5/143.7/151.5/153.7 emu/g, respectively. Due to the varied composition of hard magnetic main phases, M 9T increases gradually with the increase of Nd content ( x). SEM observation and EDX results demonstrate that more Nd and Pr elements aggregate into the 2:14:1 ferromagnetic phase, while less La and Ce elements are prone to the RE-rich region compared with the nominal ratio. As a result, the growth of M 9T becomes extraordinary under maximum external field 9 T, indicating that the (Nd0.7MM0.3)-Fe-B flake may display relatively good magnetic properties and those with higher Nd content have evident effect on magnetization, compositions, and microstructures of hard magnetic main phases. Therefore, practical application of (Nd x MM1- x )-Fe-B-sintered magnets will be very prospective.

Caste, Class and the Love-Marriage: Social Change in India

ERIC Educational Resources Information Center

Corwin, Lauren A.

1977-01-01

The present study of a small town in rural West Bengal, India, reveals a number of "love-marriages" involving individuals from castes of distinctly different ranks in the local caste hierarchy. Despite the prevailing rule of caste endogamy, inter-caste couples appear to face little difficulty. (Author)

Release of ToxCastDB and ExpoCastDB databases

EPA Science Inventory

EPA has released two databases - the Toxicity Forecaster database (ToxCastDB) and a database of chemical exposure studies (ExpoCastDB) - that scientists and the public can use to access chemical toxicity and exposure data. ToxCastDB users can search and download data from over 50...

Adhesion Casting In Low Gravity

NASA Technical Reports Server (NTRS)

Noever, David A.; Cronise, Raymond J.

1996-01-01

Adhesion casting in low gravity proposed as technique for making new and improved materials. Advantages of low-gravity adhesion casting, in comparison with adhesion casting in normal Earth gravity, comes from better control over, and greater uniformity of, thicknesses of liquid films that form on and adhere to solid surfaces during casting.

21 CFR 888.5960 - Cast removal instrument.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cast removal instrument. 888.5960 Section 888.5960...) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.5960 Cast removal instrument. (a) Identification. A cast removal instrument is an AC-powered, hand-held device intended to remove a cast from a...

40 CFR 466.20 - Applicability; description of the cast iron basis material subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability; description of the cast... Cast Iron Basis Material Subcategory § 466.20 Applicability; description of the cast iron basis... of pollutants into publicly owned treatment works from porcelain enameling of cast iron basis...

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

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

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

Adaptive significance of the Indian caste system: an ecological perspective.

PubMed

Gadgil, M; Malhotra, K C

1983-01-01

Indian society is an agglomeration of several thousand endogamous groups or castes each with a restricted geographical range and a hereditarily determined mode of subsistence. These reproductively isolated castes may be compared to biological species, and the society thought of as a biological community with each caste having its specific ecological niche. In this paper we examine the ecological-niche relationships of castes which are directly dependent on natural resources. Evidence is presented to show that castes living together in the same region had so organized their pattern of resource use as to avoid excessive intercaste competition for limiting resources. Furthermore, territorial division of the total range of the caste regulated intra-caste competition. Hence, a particular plant or animal resource in a given locality was used almost exclusively by a given lineage within a caste generation after generation. This favoured the cultural evolution of traditions ensuring sustainable use of natural resources. This must have contributed significantly to the stability of Indian caste society over several thousand years. The collapse of the base of natural resources and increasing monetarization of the economy has, however, destroyed the earlier complementarity between the different castes and led to increasing conflicts between them in recent years.

Microstructure and mechanical properties of zirconium doped NiAl/Cr(Mo) hypoeutectic alloy prepared by injection casting

NASA Astrophysics Data System (ADS)

Sheng, L. Y.; Du, B. N.; Guo, J. T.

2017-01-01

NiAl based materials has been considered as most potential candidate of turbine blade, due to its excellent high-temperature properties. However the bad room-temperature properties handicap its application. In the present paper, the zirconium doped NiAl/Cr(Mo) hypoeutectic alloy is fabricated by conventional casting and injection casting technology to improve its room-temperature properties. The microstructure and compressive properties at different temperatures of the conventionally-cast and injection-cast were investigated. The results exhibit that the conventionally-cast alloy comprises coarse primary NiAl phase and eutectic cell, which is dotted with irregular Ni2AlZr Heusler phase. Compared with the conventionally-cast alloy, the injection-cast alloy possesses refined the primary NiAl, eutectic cell and eutectic lamella. In addition, the Ni2AlZr Heusler phase become smaller and distribute uniformly. Moreover, the injection casting decrease the area fraction of primary NiAl phase at the cell interior or cell boundaries. The compressive ductility and yield strength of the injection-cast alloy at room temperature increase by about 100% and 35% over those of conventionally-cast alloy, which should be ascribed to the microstructure optimization.

The Soldiers in Societies: Defense, Regulation, and Evolution

PubMed Central

Tian, Li; Zhou, Xuguo

2014-01-01

The presence of reproductively altruistic castes is one of the primary traits of the eusocial societies. Adaptation and regulation of the sterile caste, to a certain extent, drives the evolution of eusociality. Depending on adaptive functions of the first evolved sterile caste, eusocial societies can be categorized into the worker-first and soldier-first lineages, respectively. The former is marked by a worker caste as the first evolved altruistic caste, whose primary function is housekeeping, and the latter is highlighted by a sterile soldier caste as the first evolved altruistic caste, whose task is predominantly colony defense. The apparent functional differences between these two fundamentally important castes suggest worker-first and soldier-first eusociality are potentially driven by a suite of distinctively different factors. Current studies of eusocial evolution have been focused largely on the worker-first Hymenoptera, whereas understanding of soldier-first lineages including termites, eusocial aphids, gall-dwelling thrips, and snapping shrimp, is greatly lacking. In this review, we summarize the current state of knowledge on biology, morphology, adaptive functions, and caste regulation of the soldier caste. In addition, we discuss the biological, ecological and genetic factors that might contribute to the evolution of distinct caste systems within eusocial lineages. PMID:24644427

Analysis of Mold Friction in a Continuous Casting Using Wavelet Transform

NASA Astrophysics Data System (ADS)

Ma, Yong; Fang, Bohan; Ding, Qiqi; Wang, Fangyin

2018-04-01

Mold friction (MDF) is an important parameter reflecting the lubrication condition between the initial shell and the mold during continuous casting. In this article, based on practical MDF from the slab continuous casting driven by a mechanical vibration device, the characteristics of friction were analyzed by continuous wavelet transform (CWT) and discrete wavelet transform (DWT) in different casting conditions, such as normal casting, level fluctuation, and alarming of the temperature measurement system. The results show that the CWT of friction accurately captures the subtle changes in friction force, such as the periodic characteristic of MDF during normal casting and the disordered feature of MDF during level fluctuation. Most important, the results capture the occurrence of abnormal casting and display the friction frequency characteristics at this abnormal time. In addition, in this article, there are some abnormal casting conditions, and the friction signal is stable until there is a sudden large change when abnormal casting, such as split breakout and submerged entry nozzle breakage, occurs. The DWT has a good ability to capture the friction characteristics for such abnormal situations. In particular, the potential abnormal features of MDF were presented in advance, which provides strong support for identifying abnormal casting and even preventing abnormal casting.

Very High Cycle Fatigue Behavior of a Directionally Solidified Ni-Base Superalloy DZ4

PubMed Central

Nie, Baohua; Zhao, Zihua; Liu, Shu; Chen, Dongchu; Ouyang, Yongzhong; Hu, Zhudong; Fan, Touwen; Sun, Haibo

2018-01-01

The effect of casting pores on the very high cycle fatigue (VHCF) behavior of a directionally solidified (DS) Ni-base superalloy DZ4 is investigated. Casting and hot isostatic pressing (HIP) specimens were subjected to very high cycle fatigue loading in an ambient atmosphere. The results demonstrated that the continuously descending S-N curves were exhibited for both the casting and HIP specimens. Due to the elimination of the casting pores, the HIP samples had better fatigue properties than the casting samples. The subsurface crack initiated from the casting pore in the casting specimens at low stress amplitudes, whereas fatigue crack initiated from crystallographic facet decohesion for the HIP specimens. When considering the casting pores as initial cracks, there exists a critical stress intensity threshold ranged from 1.1 to 1.3 MPam, below which fatigue cracks may not initiate from the casting pores. Furthermore, the effect of the casting pores on the fatigue limit is estimated based on a modified El Haddad model, which is in good agreement with the experimental results. Fatigue life for both the casting and HIP specimens is well predicted using the Fatigue Indicator Parameter (FIP) model. PMID:29320429

AIS/DOE Technology Roadmap Program: Strip Casting: Anticipating New Routes To Steel Sheet

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 inmore » 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.« less

Evaluation of the microstructure, secondary dendrite arm spacing, and mechanical properties of Al-Si alloy castings made in sand and Fe-Cr slag molds

NASA Astrophysics Data System (ADS)

Narasimha Murthy, I.; Babu Rao, J.

2017-07-01

The microstructure and mechanical properties of as-cast A356 (Al-Si) alloy castings were investigated. A356 alloy was cast into three different molds composed of sand, ferrochrome (Fe-Cr) slag, and a mixture of sand and Fe-Cr. A sodium silicate-CO2 process was used to make the necessary molds. Cylindrical-shaped castings were prepared. Cast products with no porosity and a good surface finish were achieved in all of the molds. These castings were evaluated for their metallography, secondary dendrite arm spacing (SDAS), and mechanical properties, including hardness, compression, tensile, and impact properties. Furthermore, the tensile and impact samples were analyzed by fractography. The results show that faster heat transfer in the Fe-Cr slag molds than in either the silica sand or mixed molds led to lower SDAS values with a refined microstructure in the products cast in Fe-Cr slag molds. Consistent and enhanced mechanical properties were observed in the slag mold products than in the castings obtained from either sand or mixed molds. The fracture surface of the slag mold castings shows a dimple fracture morphology with a transgranular fracture nature. However, the fracture surfaces of the sand mold castings display brittle fracture. In conclusion, products cast in Fe-Cr slag molds exhibit an improved surface finish and enhanced mechanical properties compared to those of products cast in sand and mixed molds.

Effects of Casting Size on Microstructure and Mechanical Properties of Spheroidal and Compacted Graphite Cast Irons: Experimental Results and Comparison with International Standards

NASA Astrophysics Data System (ADS)

Ceschini, L.; Morri, Alessandro; Morri, Andrea

2017-05-01

The aim of this research was to investigate the effects of casting size (10-210 mm) on the microstructure and mechanical properties of spheroidal (SGI) and compacted (CGI) graphite cast irons. A comparison of the experimental mechanical data with those specified by ISO standards is presented and discussed. The study highlighted that the microstructure and mechanical properties of SGI (also known as ductile or nodular cast iron) are more sensitive to casting size than CGI (also known as vermicular graphite cast irons). In particular, in both types of cast iron, hardness, yield strength and ultimate tensile strength decreased, with increasing casting size, by 27% in SGI and 17% in CGI. Elongation to failure showed, instead, an opposite trend, decreasing from 5 to 3% in CGI, while increasing from 5 to 11% in SGI. These results were related to different microstructures, the ferritic fraction being more sensitive to the casting size in SGI than CGI. Degeneration of spheroidal graphite was observed at casting size above 120 mm. The microstructural similarities between degenerated SGI and CGI suggested the proposal of a unified empirical constitutional law relating the most important microstructural parameters to the ultimate tensile strength. An outstanding result was also the finding that standard specifications underestimated the mechanical properties of both cast irons (in particular SGI) and, moreover, did not take into account their variation with casting size, at thicknesses over 60 mm.

Analysis and comparison of the biomechanical properties of univalved and bivalved cast models.

PubMed

Crickard, Colin V; Riccio, Anthony I; Carney, Joseph R; Anderson, Terrence D

2011-01-01

Fiberglass casts are frequently valved to relieve the pressure associated with upper extremity swelling after a surgical procedure or when applied after reduction of a displaced fracture in a child. Although different opinions exist regarding the valving of casts, no research to date has explored the biomechanical effects of this commonly used technique. As cast integrity is essential for the maintenance of fracture reduction, it is important to understand whether casts are structurally compromised after valving. Understanding the effects of valving on cast integrity may help guide clinicians in the technique of valving while minimizing the potential for a loss of fracture reduction. Thirty standardized cylindrical fiberglass cast models were created. Ten models were left intact, 10 were univalved, and 10 were bivalved. All the models were mechanically tested by a 3-point bending apparatus secured to a biaxial materials testing system. Load to failure and bending stiffness were recorded for each sample. Differences in load of failure and bending stiffness were compared among the groups. Unvalved cast models had the highest failure load and bending stiffness, whereas bivalved casts showed the lowest value for both failure load and bending stiffness. Univalved casts had a failure load measured to be between those of unvalved and bivalved cast models. Analysis of variance showed significance when failure load and bending stiffness data among all the groups were compared. A post hoc Bonferroni statistical analysis showed significance in bending stiffness between intact and bivalved models (P < 0.01), intact and univalved models (P < 0.01), but no significant difference in bending stiffness between univalved and bivalved models (P > 0.01). Differences in measured failure load values were found to be statistically significant among all cast models (P < 0.01). Valving significantly decreases the bending stiffness and load to failure of fiberglass casts. Univalved casts have a higher load to failure than bivalved casts. Valving adversely alters the structural integrity of fiberglass casts. This may impair a cast's ability to effectively immobilize an extremity or maintain a fracture reduction.

Ineffective higher derivative black hole hair

NASA Astrophysics Data System (ADS)

Goldstein, Kevin; Mashiyane, James Junior

2018-01-01

Inspired by the possibility that the Schwarzschild black hole may not be the unique spherically symmetric vacuum solution to generalizations of general relativity, we consider black holes in pure fourth order higher derivative gravity treated as an effective theory. Such solutions may be of interest in addressing the issue of higher derivative hair or during the later stages of black hole evaporation. Non-Schwarzschild solutions have been studied but we have put earlier results on a firmer footing by finding a systematic asymptotic expansion for the black holes and matching them with known numerical solutions obtained by integrating out from the near-horizon region. These asymptotic expansions can be cast in the form of trans-series expansions which we conjecture will be a generic feature of non-Schwarzschild higher derivative black holes. Excitingly we find a new branch of solutions with lower free energy than the Schwarzschild solution, but as found in earlier work, solutions only seem to exist for black holes with large curvatures, meaning that one should not generically neglect even higher derivative corrections. This suggests that one effectively recovers the nonhair theorems in this context.

Facile solution-processed aqueous MoOx for feasible application in organic light-emitting diode

NASA Astrophysics Data System (ADS)

Zheng, Qinghong; Qu, Disui; Zhang, Yan; Li, Wanshu; Xiong, Jian; Cai, Ping; Xue, Xiaogang; Liu, Liming; Wang, Honghang; Zhang, Xiaowen

2018-05-01

Solution-processed techniques attract increasing attentions in organic electronics for their low-cost and scalable manufacturing. We demonstrate the favorite hole injection material of solution-processed aqueous MoOx (s-MoOx) with facile fabrication process and cast successful application to constructing efficient organic light-emitting diodes (OLEDs). Atomic force microscopy and X-ray photoelectron spectroscopy analysis show that s-MoOx behaves superior film morphology and non-stoichiometry with slight oxygen deficiency. With tris(8-hydroxy-quinolinato)aluminium as emitting layer, s-MoOx based OLED shows maximum luminous efficiency of 7.9 cd/A and power efficiency of 5.9 lm/W, which have been enhanced by 43.6% and 73.5%, respectively, in comparison with the counterpart using conventional vacuum thermal evaporation MoOx. Current-voltage, impedance-voltage, phase-voltage and capacitance-voltage characteristics of hole-only devices indicate that s-MoOx with two processes of "spin-coating/annealing" shows mostly enhanced hole injection capacity and thus promoting device performance. Our experiments provide an alternative approach for constructing efficient OLED with solution process.

Experimental studies of the effect target geometry on the evolution of laser produced plasma plumes

NASA Astrophysics Data System (ADS)

Beatty, Cuyler; Anderson, Austin; Iratcabal, Jeremy; Dutra, Eric; Covington, Aaron

2016-10-01

The expansion of the laser plumes was shown to be dependent on the initial target geometry. A 16 channel framing camera was used to record the plume shape and propagation speeds were determined from analysis of the images. Plastic targets were manufactured using different methods including 3D printing, CNC machining and vacuum casting. Preliminary target designs were made using a 3D printer and ABS plastic material. These targets were then tested using a 3 J laser with a 5 ns duration pulse. Targets with a deep conical depression were shown to produce highly collimated plumes when compared to flat top targets. Preliminary results of these experiments will be discussed along with planned future experiments that will use the indented targets with a 30 J laser with a 0.8 ns duration pulse in preparation for pinched laser plume experiments at the Nevada Terawatt Facility. Other polymers that are readily available in a deuterated form will also be explored as part of an effort to develop a cost effective plasma plume target for follow on neutron production experiments. Dr. Austin Anderson.

Fabrication of silver nanowires and metal oxide composite transparent electrodes and their application in UV light-emitting diodes

NASA Astrophysics Data System (ADS)

Yan, Xingzhen; Ma, Jiangang; Xu, Haiyang; Wang, Chunliang; Liu, Yichun

2016-08-01

In this paper, we prepared the silver nanowires (AgNWs)/aluminum-doped zinc oxide (AZO) composite transparent conducting electrodes for n-ZnO/p-GaN heterojunction light emitting-diodes (LEDs) by drop casting AgNW networks and subsequent atomic layer deposition (ALD) of AZO at 150 °C. The contact resistances between AgNWs were dramatically reduced by pre-annealing in the vacuum chamber before the ALD of AZO. In this case, AZO works not only as the conformal passivation layer that protects AgNWs from oxidation, but also as the binding material that improves AgNWs adhesion to substrates. Due to the localized surface plasmons (LSPs) of the AgNWs resonant coupling with the ultraviolet (UV) light emission from the LEDs, a higher UV light extracting efficiency is achieved from LEDs with the AgNWs/AZO composite electrodes in comparison with the conventional AZO electrodes. Additionally, the antireflective nature of random AgNW networks in the composite electrodes caused a broad output light angular distribution, which could be of benefit to certain optoelectronic devices like LEDs and solar cells.

Public Health Law and Institutional Vaccine Skepticism.

PubMed

Parasidis, Efthimios

2016-12-01

Vaccine-hesitant parents are often portrayed as misinformed dilettantes clinging to unscientific Internet chatter and a debunked study that linked the MMR vaccine and autism. While this depiction may be an accurate portrayal of a small (but vocal) subset, scholars have unearthed a more complex picture that casts vaccine hesitancy in the context of broader notions of lack of trust in government and industry. At the same time, commentators have highlighted limitations of the vaccine injury compensation program and US Supreme Court Justices Sonia Sotomayor and Ruth Bader Ginsburg have argued that preemption laws that provide vaccine manufacturers with broad legal immunities create "a regulatory vacuum in which no one ensures that vaccine manufacturers adequately take account of scientific and technological advancements when designing or distributing their products." In short, the discussions surrounding vaccine hesitancy that dominate public discourse detract from serious debate as to whether amendments to vaccine-related laws can address the limitations of the existing framework governing immunizations. This commentary examines these issues through a public health law lens. Copyright © 2016 by Duke University Press.

Hamiltonian approach to GR - Part 1: covariant theory of classical gravity

NASA Astrophysics Data System (ADS)

Cremaschini, Claudio; Tessarotto, Massimo

2017-05-01

A challenging issue in General Relativity concerns the determination of the manifestly covariant continuum Hamiltonian structure underlying the Einstein field equations and the related formulation of the corresponding covariant Hamilton-Jacobi theory. The task is achieved by adopting a synchronous variational principle requiring distinction between the prescribed deterministic metric tensor \\widehat{g}(r)≡ { \\widehat{g}_{μ ν }(r)} solution of the Einstein field equations which determines the geometry of the background space-time and suitable variational fields x≡ { g,π } obeying an appropriate set of continuum Hamilton equations, referred to here as GR-Hamilton equations. It is shown that a prerequisite for reaching such a goal is that of casting the same equations in evolutionary form by means of a Lagrangian parametrization for a suitably reduced canonical state. As a result, the corresponding Hamilton-Jacobi theory is established in manifestly covariant form. Physical implications of the theory are discussed. These include the investigation of the structural stability of the GR-Hamilton equations with respect to vacuum solutions of the Einstein equations, assuming that wave-like perturbations are governed by the canonical evolution equations.

GRCop-84: A High Temperature Copper-based Alloy For High Heat Flux Applications

NASA Technical Reports Server (NTRS)

Ellis, David L.

2005-01-01

While designed for rocket engine main combustion chamber liners, GRCop-84 (Cu-8 at.% Cr-4 at.% Nb) offers potential for high heat flux applications in industrial applications requiring a temperature capability up to approximately 700 C (1292 F). GRCop-84 is a copper-based alloy with excellent elevated temperature strength, good creep resistance, long LCF lives and enhanced oxidation resistance. It also has a lower thermal expansion than copper and many other low alloy copper-based alloys. GRCop-84 can be manufactured into a variety of shapes such as tubing, bar, plate and sheet using standard production techniques and requires no special production techniques. GRCop-84 forms well, so conventional fabrication methods including stamping and bending can be used. GRCop-84 has demonstrated an ability to be friction stir welded, brazed, inertia welded, diffusion bonded and electron beam welded for joining to itself and other materials. Potential applications include plastic injection molds, resistance welding electrodes and holders, permanent metal casting molds, vacuum plasma spray nozzles and high temperature heat exchanger applications.

Influence of anode thickness on the power output of solid oxide fuel cells with (La,Sr)(Co,Fe)-type cathode

NASA Astrophysics Data System (ADS)

Menzler, Norbert H.; Haanappel, Vincent A. C.

The influence of the thickness of the anode (functional layer) on the power output of anode-supported solid oxide fuel cells with a lanthanum-strontium-cobalt-ferrite cathode was investigated. The anode was applied by vacuum slip casting and the thickness varied between 1 and 22 μm. All other material and microstructural parameters were kept constant. Single cells with dimensions of 50 mm × 50 mm and with an active cathode area of 40 mm × 40 mm were manufactured and tested in an alumina housing with air as oxidant and hydrogen with 3% water vapour as the fuel gas. Results have shown that SOFCs with anodes between 1 and 13 μm have slightly better performance than those with thicker anodes (∼1.7 A cm -2 versus 1.5 A cm -2 at 800 °C and 0.7 V). The current densities were discussed with respect to cell area specific resistance, helium leak rate of the half-cell, and microstructure.

MicroRNAs Associated with Caste Determination and Differentiation in a Primitively Eusocial Insect

PubMed Central

Collins, David H.; Mohorianu, Irina; Beckers, Matthew; Moulton, Vincent; Dalmay, Tamas; Bourke, Andrew F. G.

2017-01-01

In eusocial Hymenoptera (ants, bees and wasps), queen and worker adult castes typically arise via environmental influences. A fundamental challenge is to understand how a single genome can thereby produce alternative phenotypes. A powerful approach is to compare the molecular basis of caste determination and differentiation along the evolutionary trajectory between primitively and advanced eusocial species, which have, respectively, relatively undifferentiated and strongly differentiated adult castes. In the advanced eusocial honeybee, Apis mellifera, studies suggest that microRNAs (miRNAs) play an important role in the molecular basis of caste determination and differentiation. To investigate how miRNAs affect caste in eusocial evolution, we used deep sequencing and Northern blots to isolate caste-associated miRNAs in the primitively eusocial bumblebee Bombus terrestris. We found that the miRNAs Bte-miR-6001-5p and -3p are more highly expressed in queen- than in worker-destined late-instar larvae. These are the first caste-associated miRNAs from outside advanced eusocial Hymenoptera, so providing evidence for caste-associated miRNAs occurring relatively early in eusocial evolution. Moreover, we found little evidence that miRNAs previously shown to be associated with caste in A. mellifera were differentially expressed across caste pathways in B. terrestris, suggesting that, in eusocial evolution, the caste-associated role of individual miRNAs is not conserved. PMID:28361900

Development of a New Membrane Casting Apparatus for Studying Macrovoid Defects in Low-G

NASA Technical Reports Server (NTRS)

Lee, Hanyong; Hwang, Sun-Tak; Krantz, William B.; Greenberg, Alan R.; Khare, Vivek; Zartman, Jeremiah; Todd, Paul W.

2002-01-01

A new membrane-casting apparatus is developed for studying macrovoid defects in polymeric membranes made by the wet- and dry-casting process in low-gravity. Macrovoids are large (10-50 micron), open cavities interspersed among the smaller pores in the substructure under the gelled skin surface layer of the cast membrane. Although their occurrence is considered endemic to the wet- and dry-casting process since they can lead to compaction or skin rupture in the membrane process, recent studies suggest several useful applications such as transdermal and osmotic drug delivery systems, miniature bioreactors, etc. However, lack of knowledge about the macrovoid formation mechanism is an obstacle to further development of applications using them. An on-going debate is the role of the surface-tension-driven solutocapillary convection during macrovoid formation. The rapid growth of macrovoids within 1-5 seconds and the high polymer concentration in and near macrovoids make it difficult to explain the mechanism of macrovoid growth by diffusion alone, which is the widely accepted hypothesis proposed by Reuvers et al. The hypothesis advanced by our research group can explain this rapid growth via a mechanism that involves diffusion from the casting solution in the meta-stable region to the macrovoid enhanced by solutocapillary convection induced by the steep nonsolvent concentration gradient in the vicinity of the macrovoid. Since macrovoid growth is hypothesized to be the interplay of a solutocapillary-induced driving force counteracted by viscous drag and buoyancy, eliminate the latter provides a means for testing this hypothesis. Moreover, free convection mass transfer in the nonsolvent immersion bath used to cause phase-separation in membrane casting complicates developing a model for both the wet-casting process and macrovoid growth. The low-g environment minimizes gravitationally induced free convection thereby permitting a tractable solution to the ternary diffusion equations that characterize membrane formation. NASA's Parabolic Flight Research Aircraft provides a small window of low-g (approximately 25 s) that can be used to study macrovoid development in both wet- and dry-cast membranes if an appropriate casting apparatus is used. This casting apparatus should be able to cast the membrane in both low- and high-g in a manner so that essential one-dimensional mass transfer conditions are achieved to insure lateral uniformity in the membrane. The apparatus used in previous research on membrane casting in low-gravity was operated with the plunger driven mechanism. The spring-loaded plunger pushes the bottom block containing the polymer casting solution well directly under the absorbent chamber located in the upper stationary block. However, membranes made via this casting apparatus often displayed lateral nonuniformities that precluded obtaining quantitative information on the macrovoid growth process. Thus, it was necessary to determine the reason for these structural irregularities observed in the low-g casting apparatus. Both experimental as well as computer simulation studies of the low-g casting apparatus established that the impulsive action of the plunger caused the undesired structural nonuniformities. The simulation results showed that the width-to-depth aspect ratio of the shallow well that contains the casting solution in this apparatus was not an important factor in minimizing this problem. Even for a 40:1 (width : depth) aspect ratio, any convection induced by the horizontal motion of the interface of the casting solution will be damped out within 6.25x10(exp 4) seconds. However, the experimental studies revealed that the impulsive motion of the plunger caused a 'sloshing' of the casting solution that had to be eliminated. Therefore, the plungerdriven mechanism was changed to a cam-driven mechanism that did not cause any impulsive motion of the casting solution. Other refinements to this new membrane-casting apparatus include provision for removing the membranes from the casting wells in a less destructive manner. This was accomplished by using a slit geometry for the casting well that permitted disassembly for removal of the cast membrane. The materials used in the construction of this casting apparatus were chosen to insure wetting at the side walls and to maintain precise control of the thickness of the polymer solution in the casting well. An additional provision in this new casting apparatus is the ability to carry out both wet- as well as dry-casting. As such, this apparatus permitted the first studies of the wet-casting of polymeric membranes in low-g. Both wet- and dry-casting experiments on NASA's KC-135 research aircraft employing this new membrane-casting apparatus are scheduled in July 2002. The morphology of the resulting membranes will be characterized using an environmental scanning electron microscope (ESEM). The results of these low-g studies will be reported later.

Cross-Validation of the Computerized Adaptive Screening Test (CAST).

ERIC Educational Resources Information Center

Pliske, Rebecca M.; And Others

The Computerized Adaptive Screening Test (CAST) was developed to provide an estimate at recruiting stations of prospects' Armed Forces Qualification Test (AFQT) scores. The CAST was designed to replace the paper-and-pencil Enlistment Screening Test (EST). The initial validation study of CAST indicated that CAST predicts AFQT at least as accurately…

Materials processing threshold report: 2. Use of low gravity for cast iron process development

NASA Technical Reports Server (NTRS)

Frankhouser, W. L.

1980-01-01

Potential applications of a low gravity environment of interest to the commercial producers of cast iron were assessed to determine whether low gravity conditions offer potential opportunities to producers for improving cast iron properties and expanding the use of cast irons. The assessment is limited to the gray and nodular types of iron, however, the findings are applicable to all cast irons. The potential advantages accrued through low gravity experiments with cast irons are described.

Characterization of calpastatin gene in fish: its potential role in muscle growth and fillet quality.

PubMed

Salem, Mohamed; Yao, Jianbo; Rexroad, Caird E; Kenney, P Brett; Semmens, Kenneth; Killefer, John; Nath, Joginder

2005-08-01

Calpastatin (CAST), the specific inhibitor of the calpain proteases, plays a role in muscle growth and meat quality. In rainbow trout (RBT), we identified cDNAs coding for two CAST isoforms, a long (CAST-L) and a short isoform (CAST-S), apparently derived from two different genes. Zebrafish and pufferfish CAST cDNA and genomic sequences were retrieved from GenBank and their exon/intron structures were characterized. Fish CASTs are novel in that they have fewer repetitive inhibitory domains as compared to their mammalian counterparts (one or two vs. four). The expressions of CAST mRNAs were measured in three RBT strains with different growth rates and fillet firmness that were fed either high energy or control diets. CAST-L and S expressions were significantly lower (p<0.01) in the strain that has the slowest growth rate and yielded the softest fillet. Strain or diet did not affect level of calpain mRNAs. However, the decrease in the CAST/calpain ratio at the mRNA level did not lead to a corresponding change in the calpain catalytic activity. Further investigation should reveal a potential use of the CAST gene as a tool to monitor fish muscle growth and fillet firmness.

Chemical-Gene Interactions from ToxCast Bioactivity Data ...

EPA Pesticide Factsheets

Characterizing the effects of chemicals in biological systems is often summarized by chemical-gene interactions, which have sparse coverage in the literature. The ToxCast chemical screening program has produced bioactivity data for nearly 2000 chemicals and over 450 gene targets. To evaluate the information gained from the ToxCast project, a ToxCast bioactivity network was created comprising ToxCast chemical-gene interactions based on assay data and compared to a chemical-gene association network from literature. The literature network was compiled from PubMed articles, excluding ToxCast publications, mapped to genes and chemicals. Genes were identified by curated associations available from NCBI while chemicals were identified by PubChem submissions. The frequencies of chemical-gene associations from the literature network were log-scaled and then compared to the ToxCast bioactivity network. In total, 140 times more chemical-gene associations were present in the ToxCast network in comparison to the literature-derived network highlighting the vast increase in chemical-gene interactions putatively elucidated by the ToxCast research program. There were 165 associations found in the literature network that were reproduced by ToxCast bioactivity data, and 336 associations in the literature network were not reproduced by the ToxCast bioactivity network. The literature network relies on the assumption that chemical-gene associations represent a true chemical-gene inte

Cool Cast Facts

MedlinePlus

... Kinds of Casts? Most casts are made of fiberglass. Fiberglass is a kind of plastic that can be ... to the body part. It dries hard. Some fiberglass casts are waterproof. Doctors only use this type ...

Casting for infantile scoliosis: the pitfall of increased peak inspiratory pressure.

PubMed

Dhawale, Arjun A; Shah, Suken A; Reichard, Samantha; Holmes, Laurens; Brislin, Robert; Rogers, Kenneth; Mackenzie, William G

2013-01-01

Serial cast correction is a popular treatment option for progressive infantile scoliosis. Body casting can lead to chest and abdominal expansion restriction and result in decreased chest wall compliance. There are no studies evaluating the effects of casting on ventilation in infantile scoliosis. This study examines changes in peak inspiratory pressure (PIP) during serial casting for infantile scoliosis. We retrospectively reviewed data obtained from 37 serial Cotrel elongation, derotation, and flexion cast corrections in patients with infantile scoliosis. Patient demographics, radiographic measurements, and anesthesia data were recorded. Anesthesia technique was standardized: children were intubated with rigid endotracheal tubes (ETTs); tidal volume was held constant at 8 to 10 cm(3)/kg using volume control ventilation; and PIP was recorded at baseline, after cast application before window cutout, and after window cutout before extubation. Any complications were documented. We assessed the PIP changes with a repeated measures analysis of variance (ANOVA). The mean age at first casting was 21.8 months (range, 12 to 42 mo) and mean follow-up since first casting was 22.4 months (range, 13 to 40 mo) with mean major Cobb angle of 53±15 degrees. The mean PIP was 15.5±4.9 cm H(2)O before casting, 31.9±7.9 cm H(2)O after cast application, and 20.4±5.6 cm H2O after making windows. There was a 106% increase after casting and 32% increase after window cutout from the baseline PIP levels. There was a significant difference in PIP on repeated measures ANOVA (P<0.0001). Intraoperatively, there was difficulty in maintaining ventilation during 2 procedures and 1 hypotensive episode. One patient developed hypoxemia after casting and another had delayed difficulty in breathing. Casting resulted in an increased PIP due to transient restrictive pulmonary process; after windows were cut out, the PIP reduced but not to baseline. In patients with underlying pulmonary disease, the casting process may induce respiratory complications, and a proper period of observation after casting is necessary. Case series, level 4.

GRINDING ROOM AT SOUTHERN DUCTILE CASTING COMPANY, BESSEMER FOUNDRY SHOWING ...

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

GRINDING ROOM AT SOUTHERN DUCTILE CASTING COMPANY, BESSEMER FOUNDRY SHOWING WHEELABORATOR THAT IMPALE SHOT AT TUMBLING CASTINGS TO REMOVE EXCESS SURFACE METALS AND SAND; ANNEALING OVENS TO HEAT CERTAIN CASTINGS TO ACHIEVE A DESIRED CHARACTERISTIC; AND GRINDING WHEELS USED TO REMOVE GATES. - Southern Ductile Casting Company, Grinding & Shipping, 2217 Carolina Avenue, Bessemer, Jefferson County, AL

21 CFR 880.6185 - Cast cover.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cast cover. 880.6185 Section 880.6185 Food and....6185 Cast cover. (a) Identification. A cast cover is a device intended for medical purposes that is made of waterproof material and placed over a cast to protect it from getting wet during a shower or a...

Processing of IN-718 Lattice Block Castings

NASA Technical Reports Server (NTRS)

Hebsur, Mohan G.

2002-01-01

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

Research on the influence of moulding-casting technology on the quality of castings

NASA Astrophysics Data System (ADS)

Josan, A.; Pinca Bretotean, C.; Raţiu, S.; Ardelean, E.; Ardelean, M.

2017-05-01

The quality of castings has a particularly role in the Romanian foundries. In this context, quality assurance is the overall objective of the foundries. The paper presents the critical analysis performed on moulding-casting technology of the type Lifting mechanism. This casting is a subset of the lifting and rotating mechanism of the furnace vault. The casting analysed is a medium size, with weight of 114 kg. The current moulding-casting technology involves moulding into three mould-parts leading to the occurrence of defects (decentering of the core, displacement of the lower mould and the middle mould and occurrence of burrs in area separated. Thus, to reduce the percentage of defects registered in industrial practice is necessary to change the moulding-casting technology. This requires the use of two mould-parts, re-dimensioning of the core and the core box and dimensioning of the runner network. The adoption of these changes in industrial practice has direct implications on the cost of casting and foundry costs default.

Pneumatic gap sensor and method

DOEpatents

Bagdal, Karl T.; King, Edward L.; Follstaedt, Donald W.

1992-01-01

An apparatus and method for monitoring and maintaining a predetermined width in the gap between a casting nozzle and a casting wheel, wherein the gap is monitored by means of at least one pneumatic gap sensor. The pneumatic gap sensor is mounted on the casting nozzle in proximity to the casting surface and is connected by means of a tube to a regulator and a transducer. The regulator provides a flow of gas through a restictor to the pneumatic gap sensor, and the transducer translates the changes in the gas pressure caused by the proximity of the casting wheel to the pneumatic gap sensor outlet into a signal intelligible to a control device. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces. The apparatus and method enables accurate monitoring of the actual casting gap in a simple and reliable manner resistant to the extreme temperatures and otherwise hostile casting environment.

Pneumatic gap sensor and method

DOEpatents

Bagdal, K.T.; King, E.L.; Follstaedt, D.W.

1992-03-03

An apparatus and method for monitoring and maintaining a predetermined width in the gap between a casting nozzle and a casting wheel, wherein the gap is monitored by means of at least one pneumatic gap sensor. The pneumatic gap sensor is mounted on the casting nozzle in proximity to the casting surface and is connected by means of a tube to a regulator and a transducer. The regulator provides a flow of gas through a restictor to the pneumatic gap sensor, and the transducer translates the changes in the gas pressure caused by the proximity of the casting wheel to the pneumatic gap sensor outlet into a signal intelligible to a control device. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces. The apparatus and method enables accurate monitoring of the actual casting gap in a simple and reliable manner resistant to the extreme temperatures and otherwise hostile casting environment. 6 figs.

Energy Saving Melting and Revert Reduction (E-SMARRT): Precision Casting of Steel

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dr. Von L. Richards

2011-09-30

This project addresses improvements in metal casting processes by reducing scrap and reducing the cost of production, due to scrap reduction from investment casting and yield improvement offered by lost foam casting as compared to no-bake or green sand molding. The objectives for the investment casting portion of the subtask are to improve knowledge of fracture toughness of mold shells and the sources of strength limiting flaws and to understand the effects of wax reclamation procedures on wax properties. Applying 'clean steel' approaches to pouring technology and cleanliness in investment casting of steel are anticipated to improve incoming materials inspectionmore » procedures as they affect the microstructure and toughness of the shell. This project focused on two areas of study in the production of steel castings to reduce scrap and save energy: (1) Reducing the amount of shell cracking in investment cast steel production; (2) Investigate the potential of lost foam steel casting The basic findings regarding investment casting shell cracking were: (1) In the case of post pouring cracking, this could be related to phase changes in silica upon cooling and could be delayed by pouring arrangement strategies that maintained the shell surface at temperature for longer time. Employing this delay resulted in less adherent oxidation of castings since the casting was cooler at the time o fair exposure. (2) A model for heat transfer through water saturated shell materials under steam pressure was developed. (3) Initial modeling result of autoclave de-waxing indicated the higher pressure and temperature in the autoclave would impose a steeper temperature gradient on the wax pattern, causing some melt flow prior to bulk expansion and decreasing the stress on the green shell. Basic findings regarding lost foam casting of steel at atmospheric pressure: (1) EPS foam generally decomposes by the collapse mode in steel casting. (2) There is an accumulation of carbon pick-up at the end of the casting opposite the gate. (3) It is recommended that lost foam castings in steel be gated for a quiescent fill in an empty cavity mold to prevent foam occlusion defects from the collapse mode. The energy benefit is primarily in yield savings and lower casting weight per function due to elimination of draft and parting lines for the larger lost foam castings. For the smaller investment casting, scrap losses due to shell cracking will be reduced. Both of these effects will reduce the metal melted per good ton of castings. There will also be less machine stock required per casting which is a yield savings and a small additional energy savings in machining. Downstream savings will come from heavy truck and railroad applications. Application of these processes to heavy truck castings will lighten the heavy truck fleet by about ten pounds per truck. Using ten years to achieve full penetration of the truck fleet at linear rate this will result in a fuel savings of 131 trillion BTU over ten years.« less

Generation and evaluation of 3D digital casts of maxillary defects based on multisource data registration: A pilot clinical study.

PubMed

Ye, Hongqiang; Ma, Qijun; Hou, Yuezhong; Li, Man; Zhou, Yongsheng

2017-12-01

Digital techniques are not clinically applied for 1-piece maxillary prostheses containing an obturator and removable partial denture retained by the remaining teeth because of the difficulty in obtaining sufficiently accurate 3-dimensional (3D) images. The purpose of this pilot clinical study was to generate 3D digital casts of maxillary defects, including the defective region and the maxillary dentition, based on multisource data registration and to evaluate their effectiveness. Twelve participants with maxillary defects were selected. The maxillofacial region was scanned with spiral computer tomography (CT), and the maxillary arch and palate were scanned using an intraoral optical scanner. The 3D images from the CT and intraoral scanner were registered and merged to form a 3D digital cast of the maxillary defect containing the anatomic structures needed for the maxillary prosthesis. This included the defect cavity, maxillary dentition, and palate. Traditional silicone impressions were also made, and stone casts were poured. The accuracy of the digital cast in comparison with that of the stone cast was evaluated by measuring the distance between 4 anatomic landmarks. Differences and consistencies were assessed using paired Student t tests and the intraclass correlation coefficient (ICC). In 3 participants, physical resin casts were produced by rapid prototyping from digital casts. Based on the resin casts, maxillary prostheses were fabricated by using conventional methods and then evaluated in the participants to assess the clinical applicability of the digital casts. Digital casts of the maxillary defects were generated and contained all the anatomic details needed for the maxillary prosthesis. Comparing the digital and stone casts, a paired Student t test indicated that differences in the linear distances between landmarks were not statistically significant (P>.05). High ICC values (0.977 to 0.998) for the interlandmark distances further indicated the high degree of consistency between the digital and stone casts. The maxillary prostheses showed good clinical effectiveness, indicating that the corresponding digital casts met the requirements for clinical application. Based on multisource data from spiral CT and the intraoral scanner, 3D digital casts of maxillary defects were generated using the registration technique. These casts were consistent with conventional stone casts in terms of accuracy and were suitable for clinical use. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Dimensional accuracy and surface property of titanium casting using gypsum-bonded alumina investment.

PubMed

Yan, Min; Takahashi, Hidekazu; Nishimura, Fumio

2004-12-01

The aim of the present study was to evaluate the dimensional accuracy and surface property of titanium casting obtained using a gypsum-bonded alumina investment. The experimental gypsum-bonded alumina investment with 20 mass% gypsum content mixed with 2 mass% potassium sulfate was used for five cp titanium castings and three Cu-Zn alloy castings. The accuracy, surface roughness (Ra), and reaction layer thickness of these castings were investigated. The accuracy of the castings obtained from the experimental investment ranged from -0.04 to 0.23%, while surface roughness (Ra) ranged from 7.6 to 10.3microm. A reaction layer of about 150 microm thickness under the titanium casting surface was observed. These results suggested that the titanium casting obtained using the experimental investment was acceptable. Although the reaction layer was thin, surface roughness should be improved.

An investigation of squeeze-cast alloy 718

NASA Technical Reports Server (NTRS)

Gamwell, W. R.

1993-01-01

Alloy 718 billets produced by the squeeze-cast process have been evaluated for use as potential replacements for propulsion engine components which are normally produced from forgings. Alloy 718 billets were produced using various processing conditions. Structural characterizations were performed on 'as-cast' billets. As-cast billets were then homogenized and solution treated and aged according to conventional heat-treatment practices for this alloy. Mechanical property evaluations were performed on heat-treated billets. As-cast macrostructures and microstructures varied with squeeze-cast processing parameters. Mechanical properties varied with squeeze-cast processing parameters and heat treatments. One billet exhibited a defect free, refined microstructure, with mechanical properties approaching those of wrought alloy 718 bar, confirming the feasibility of squeeze-casting alloy 718. However, further process optimization is required, and further structural and mechanical property improvements are expected with process optimization.

The efficiencies of cast blasting in wide pits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Martin, R.L.; King, M.G.

Blasting activities in all four pits at Thunder Basin Coal`s Black Thunder Mine are focused on cast blasting. With widths varying from 190 feet to 265 feet and bench heights varying from 90 feet to 175 feet, casting efficiencies vary with different geometry`s. For example, the percent cast to final in the 200 foot pit is on the average higher than the 270 foot pit. The powder factors are somewhat higher in the narrower pits, thus increasing the cost of blasting. This leads to a very detailed look at the actual benefit of cast blasting and the associated cost ofmore » these benefits. The simple solution would be to reduce the width of the pits, thereby increasing the percent cast to final. However, the lower rehandle and low coal loss associated with wide pits would be fortified. Upon further review it becomes obvious that the wider pits could not be compared to the narrow pits with the cast to final percent indices. The focus should be shifted to cubic yards cast to final per lineal foot of pit. This will allow for more accurate measures of the casting efficiency of the shot. When comparing the pits with these indices their performances were much closer than the percent cast to final indices. The powder factors being higher in the narrow pits drove up the cost per cubic yard cast to final. Therefore, even though the percent cast to final was higher, the cost per cubic yard was also higher.« less

A Comparative Evaluation of the Effect of Double Casting Technique Using Functionally Generated Path and Conventional Single Casting with Respect to Functional Articulation, Patient Satisfaction and Chair Side Time, in Single Unit Molar Teeth: An In Vivo Study.

PubMed

Memon, Sarfaraz

2014-12-01

A stable centric occlusal position that shows no evidence of occlusal disease should not be altered. Confirmative restorative dentistry deals with making restorations that are in harmony with existing jaw relations. Conventional techniques for construction have been unsuccessful in producing a prosthesis that can be inserted without minor intraoral occlusal adjustment. This study was conducted to evaluate the benefits of the double casting technique with FGP over the conventional casting technique. Ten patients with root canal treated maxillary molar were selected for the fabrication of metal crown. Two techniques, one involving the conventional fabrication and other using functionally generated path with double casting were used to fabricate the prosthesis. A comparison based on various parameters which was done between the two techniques. The change in the height of castings for the double casting group was less compared to the conventional group and was highly statistically significant (P < 0.001). The time taken for occlusal correction was significantly lower in double casting group than the conventional group (P < 0.001). The patient satisfaction (before occlusal correction) indicated better satisfaction for double casting group compared to conventional (P < 0.01). The functionally generated path with double casting technique resulted in castings which had better dimensional accuracy, less occlusal correction and better patient satisfaction compared to the conventional castings.

Vascular Corrosion Casting: Review of Advantages and Limitations in the Application of Some Simple Quantitative Methods.

PubMed

Hossler, Fred E.; Douglas, John E.

2001-05-01

Vascular corrosion casting has been used for about 40 years to produce replicas of normal and abnormal vasculature and microvasculature of various tissues and organs that could be viewed at the ultrastructural level. In combination with scanning electron microscopy (SEM), the primary application of corrosion casting has been to describe the morphology and anatomical distribution of blood vessels in these tissues. However, such replicas should also contain quantitative information about that vasculature. This report summarizes some simple quantitative applications of vascular corrosion casting. Casts were prepared by infusing Mercox resin or diluted Mercox resin into the vasculature. Surrounding tissues were removed with KOH, hot water, and formic acid, and the resulting dried casts were observed with routine SEM. The orientation, size, and frequency of vascular endothelial cells were determined from endothelial nuclear imprints on various cast surfaces. Vascular volumes of heart, lung, and avian salt gland were calculated using tissue and resin densities, and weights. Changes in vascular volume and functional capillary density in an experimentally induced emphysema model were estimated from confocal images of casts. Clearly, corrosion casts lend themselves to quantitative analysis. However, because blood vessels differ in their compliances, in their responses to the toxicity of casting resins, and in their response to varying conditions of corrosion casting procedures, it is prudent to use care in interpreting this quantitative data. Some of the applications and limitations of quantitative methodology with corrosion casts are reviewed here.

Investigation of Materials Processing Technology

DTIC Science & Technology

1993-07-01

Figure 6: Time-temperature curves of A357 casting in Cu mold ................. 12 Figure 7: Time-temperature curves of 17 -4 casting in ceramic mold...simulation of 17 -4 ................ 17 Figure 12: IHTC from IHEAT simulation of 17 -4 casting ..................... 18 Figure 13: Temperature profiles...mold used for Ti castings .......................... 23 Figure 16: Cooling curves for a Ti casting in ceramic mold .................. 24 Figure 17

49 CFR 192.373 - Service lines: Cast iron and ductile iron.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Service lines: Cast iron and ductile iron. 192.373... Regulators, and Service Lines § 192.373 Service lines: Cast iron and ductile iron. (a) Cast or ductile iron... cast iron pipe or ductile iron pipe is installed for use as a service line, the part of the service...

Hot forging of roll-cast high aluminum content magnesium alloys

NASA Astrophysics Data System (ADS)

Kishi, Tomohiro; Watari, Hisaki; Suzuki, Mayumi; Haga, Toshio

2017-10-01

This paper reports on hot forging of high aluminum content magnesium alloy sheets manufactured using horizontal twin-roll casting. AZ111 and AZ131 were applied for twin-roll casting, and a hot-forging test was performed to manufacture high-strength magnesium alloy components economically. For twin-roll casting, the casting conditions of a thick sheet for hot forging were investigated. It was found that twin-roll casting of a 10mm-thick magnesium alloy sheet was possible at a roll speed of 2.5m/min. The grain size of the cast strip was 50 to 70µm. In the hot-forging test, blank material was obtained from as-cast strip. A servo press machine with a servo die cushion was used to investigate appropriate forging conditions (e.g., temperature, forging load, and back pressure) for twin-roll casts (TRCs) AZ111 and AZ131. It was determined that high aluminum content magnesium alloy sheets manufactured using twin-roll casting could be forged with a forging load of 150t and a back pressure of 3t at 420 to 430°C. Applying back pressure during hot forging effectively forged a pin-shaped product.

Casting materials and their application in research and teaching.

PubMed

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.

Development and evaluation of a digital dental modeling method based on grating projection and reverse engineering software.

PubMed

Zhou, Qin; Wang, Zhenzhen; Chen, Jun; Song, Jun; Chen, Lu; Lu, Yi

2016-01-01

For reasons of convenience and economy, attempts have been made to transform traditional dental gypsum casts into 3-dimensional (3D) digital casts. Different scanning devices have been developed to generate digital casts; however, each has its own limitations and disadvantages. The purpose of this study was to develop an advanced method for the 3D reproduction of dental casts by using a high-speed grating projection system and noncontact reverse engineering (RE) software and to evaluate the accuracy of the method. The methods consisted of 3 main steps: the scanning and acquisition of 3D dental cast data with a high-resolution grating projection system, the reconstruction and measurement of digital casts with RE software, and the evaluation of the accuracy of this method using 20 dental gypsum casts. The common anatomic landmarks were measured directly on the gypsum casts with a Vernier caliper and on the 3D digital casts with the Geomagic software measurement tool. Data were statistically assessed with the t test. The grating projection system had a rapid scanning speed, and smooth 3D dental casts were obtained. The mean differences between the gypsum and 3D measurements were approximately 0.05 mm, and no statistically significant differences were found between the 2 methods (P>.05), except for the measurements of the incisor tooth width and maxillary arch length. A method for the 3D reconstruction of dental casts was developed by using a grating projection system and RE software. The accuracy of the casts generated using the grating projection system was comparable with that of the gypsum casts. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

Focused Molding Using Adhesive Pads in Mehta Casting for Early-Onset Scoliosis.

PubMed

Abraham, Roby; Sponseller, Paul D

2014-11-01

Prospective clinical series. To determine the effect of adhesive pads placed over the apex of scoliosis curves on curve correction 1) after the first cast and 2) after the final cast. Early-onset scoliosis is often effectively managed by serial casting. Properly localizing the apex of the molds with the cast in place is challenging. The authors explored the effectiveness of a novel technique: incorporation of adhesive pads placed over the major curve apex before Mehta casting. The 27 patients who received body casts (2000-2013) were divided into 2 groups: those without and with apical adhesive pads (5-6 layers of pads placed on the major curve's apex during casting): non-pad (NP) group (n = 12) and pad (P) group (n = 15), respectively. Groups were compared regarding the percentage of Cobb angle change from the first cast and curve correction to a Cobb angle of <25° with Student t and chi-square tests (significance was p < .05). The mean percentage of major first-cast curve correction was 39% ± 18% and 56% ± 17% in the NP and P groups, respectively. Of the 26 patients out of a cast, 11 (42%) had a Cobb angle of <25°: 3 (25%) and 8 (57%) in the NP and P groups, respectively. The mean differences between the 2 groups in percentage of major curve correction and this Cobb angle correction were significant: p = .023 and .005, respectively. Adhesive pads placed over major curve(s) during Mehta casting were effective in increasing the amount of major curve correction from the first cast for idiopathic early-onset scoliosis and in decreasing curves to <25° at final follow-up. Copyright © 2014 Scoliosis Research Society. Published by Elsevier Inc. All rights reserved.

A comparison between the dimensions of positive transtibial residual limb molds prepared by air pressure casting and weight-bearing casting methods.

PubMed

Hajiaghaei, Behnam; Ebrahimi, Ismail; Kamyab, Mojtaba; Saeedi, Hassan; Jalali, Maryam

2016-01-01

Creating a socket with proper fit is an important factor to ensure the comfort and control of prosthetic devices. Several techniques are commonly used to cast transtibial stumps but their effect on stump shape deformation is not well understood. This study compares the dimensions, circumferences and volumes of the positive casts and also the socket comfort between two casting methods. Our hypothesis was that the casts prepared by air pressure method have less volume and are more comfortable than those prepared by weight bearing method. Fifteen transtibial unilateral amputees participated in the study. Two weight bearing and air pressure casting methods were utilized for their residual limbs. The diameters and circumferences of various areas of the residual limbs and positive casts were compared. The volumes of two types of casts were measured by a volumeter and compared. Visual Analogue Scale (VAS) was used to measure the sockets fit comfort. Circumferences at 10 and 15 cm below the patella on the casts were significantly smaller in air pressure casting method compared to the weight bearing method (p=0.00 and 0.01 respectively). The volume of the cast in air pressure method was lower than that of the weight bearing method (p=0.006). The amputees found the fit of the sockets prepared by air pressure method more comfortable than the weight bearing sockets (p=0.015). The air pressure casting reduced the circumferences of the distal portion of residual limbs which has more soft tissue and because of its snug fit it provided more comfort for amputees, according to the VAS measurements.

Strain Rate Dependency of Bronze Metal Matrix Composite Mechanical Properties as a Function of Casting Technique

NASA Astrophysics Data System (ADS)

Brown, Lloyd; Joyce, Peter; Radice, Joshua; Gregorian, Dro; Gobble, Michael

2012-07-01

Strain rate dependency of mechanical properties of tungsten carbide (WC)-filled bronze castings fabricated by centrifugal and sedimentation-casting techniques are examined, in this study. Both casting techniques are an attempt to produce a functionally graded material with high wear resistance at a chosen surface. Potential applications of such materials include shaft bushings, electrical contact surfaces, and brake rotors. Knowledge of strain rate-dependent mechanical properties is recommended for predicting component response due to dynamic loading or impact events. A brief overview of the casting techniques for the materials considered in this study is followed by an explanation of the test matrix and testing techniques. Hardness testing, density measurement, and determination of the volume fraction of WC particles are performed throughout the castings using both image analysis and optical microscopy. The effects of particle filling on mechanical properties are first evaluated through a microhardness survey of the castings. The volume fraction of WC particles is validated using a thorough density survey and a rule-of-mixtures model. Split Hopkinson Pressure Bar (SHPB) testing of various volume fraction specimens is conducted to determine strain dependence of mechanical properties and to compare the process-property relationships between the two casting techniques. The baseline performances of C95400 bronze are provided for comparison. The results show that the addition of WC particles improves microhardness significantly for the centrifugally cast specimens, and, to a lesser extent, in the sedimentation-cast specimens, largely because the WC particles are more concentrated as a result of the centrifugal-casting process. Both metal matrix composites (MMCs) demonstrate strain rate dependency, with sedimentation casting having a greater, but variable, effects on material response. This difference is attributed to legacy effects from the casting process, namely, porosity and localized WC particle grouping.

Precision cast vs. wrought superalloys

NASA Technical Reports Server (NTRS)

Tien, J. K.; Borofka, J. C.; Casey, M. E.

1986-01-01

While cast polycrystalline superalloys recommend themselves in virtue of better 'buy-to-fly' ratios and higher strengthening gamma-prime volume fractions than those of wrought superalloys, the expansion of their use into such critical superalloy applications as gas turbine hot section components has been slowed by insufficient casting process opportunities for microstructural control. Attention is presently drawn, however, to casting process developments facilitating the production of defect-tolerant superalloy castings having improved fracture reliability. Integrally bladed turbine wheel and thin-walled turbine exhaust case near-net-shape castings have been produced by these means.

Improved Safety and Cost Savings from Reductions in Cast-Saw Burns After Simulation-Based Education for Orthopaedic Surgery Residents.

PubMed

Bae, Donald S; Lynch, Hayley; Jamieson, Katherine; Yu-Moe, C Winnie; Roussin, Christopher

2017-09-06

The purpose of this investigation was to characterize the clinical efficacy and cost-effectiveness of simulation training aimed at reducing cast-saw injuries. Third-year orthopaedic residents underwent simulation-based instruction on distal radial fracture reduction, casting, and cast removal using an oscillating saw. The analysis compared incidences of cast-saw injuries and associated costs before and after the implementation of the simulation curriculum. Actual and potential costs associated with cast-saw injuries included wound care, extra clinical visits, and potential total payment (indemnity and expense payments). Curriculum costs were calculated through time-derived, activity-based accounting methods. The researchers compared the costs of cast-saw injuries and the simulation curriculum to determine overall savings and return on investment. In the 2.5 years prior to simulation, cast-saw injuries occurred in approximately 4.3 per 100 casts cut by orthopaedic residents. For the 2.5-year period post-simulation, the injury rate decreased significantly to approximately 0.7 per 100 casts cut (p = 0.002). The total cost to implement the casting simulation was $2,465.31 per 6-month resident rotation. On the basis of historical data related to cast-saw burns (n = 6), total payments ranged from $2,995 to $25,000 per claim. The anticipated savings from averted cast-saw injuries and associated medicolegal payments in the 2.5 years post-simulation was $27,131, representing an 11-to-1 return on investment. Simulation-based training for orthopaedic surgical residents was effective in reducing cast-saw injuries and had a high theoretical return on investment. These results support further investment in simulation-based training as cost-effective means of improving patient safety and clinical outcomes. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Casting of Ti-6Al-4V alloy compared with pure Ti in an Ar-arc casting machine.

PubMed

Syverud, M; Okabe, T; Herø, H

1995-10-01

Dental prostheses of Ti are normally cast in pure Ti. Some appliances, however, require higher yield strength. Casting of Ti alloys is of interest in such cases. The objective of the present work was to study the quality of castings made of Ti-6Al-4V compared with those made of pure Ti. Casting was made into a mold kept at room temperature using a MgO-Al2O3 investment. A standardized five-unit bridge was cast, consisting of two cylindrical crowns with sharp margins and three pontics. The overall mold filling was satisfactory. The margins of the casting alloys were, however, more rugged and incomplete than those of pure Ti. The most likely reason for this difference is the increased formation of dendrites in the alloy and thus more resistance to fluid flow. Furthermore, the sprue of the alloy was also found to contain some spherical, internal pores. Such pores were rare in the pure Ti castings. The surface reactions were found to be minimal for both of the materials. Increased casting deficiencies observed in the cast bridges of the Ti-6Al-4V alloy, compared with pure Ti, were: 1) the margins of the crowns in the bridge were less complete and 2) there was a tendency to an increased internal porosity, particularly in the sprues.

An audit of complications of fiberglass cast and hybrid cast for fractures of the foot, ankle and forearm in a Swedish emergency department.

PubMed

Ekwall, Anna; Carlberg, Eva; Palmberg, Gunilla; Sloberg, Rut

2018-06-01

Patients of all ages present to the Emergency Department (ED) with fractures that require immobilization using a cast. Various casting materials are used, all with advantages and disadvantages and there are considerable risks associated with fracture management using cast immobilization. The frequency and severity of complications from fiberglass or hybrid casts applied in the emergency setting has not previously been studied. The aim of this audit was to describe all the complications that occurred within 30 days in patients who had a fiberglass cast applied for immobilization of uncomplicated, non-angulated fractures of the foot, ankle or forearm. A retrospective care record audit was conducted that included 430 patients. The most common complications found were skin complications and cast related problems. No severe complications (e.g. compartment syndrome, venous thromboembolism or infection) were found. Fiberglass casts did not cause severe complications in this group of patients with uncomplicated fractures of the extremities. However, 25% of the patients experienced some form of complication. Interventions are needed that minimize the frequency of complications. As with all healthcare interventions, it is crucial that staff applying casts and providing follow-up care are competent. If casts are applied correctly and the patient is well informed and concordant, complications can be avoided. Copyright © 2018 Elsevier Ltd. All rights reserved.

The transcriptomic and evolutionary signature of social interactions regulating honey bee caste development.

PubMed

Vojvodic, Svjetlana; Johnson, Brian R; Harpur, Brock A; Kent, Clement F; Zayed, Amro; Anderson, Kirk E; Linksvayer, Timothy A

2015-11-01

The caste fate of developing female honey bee larvae is strictly socially regulated by adult nurse workers. As a result of this social regulation, nurse-expressed genes as well as larval-expressed genes may affect caste expression and evolution. We used a novel transcriptomic approach to identify genes with putative direct and indirect effects on honey bee caste development, and we subsequently studied the relative rates of molecular evolution at these caste-associated genes. We experimentally induced the production of new queens by removing the current colony queen, and we used RNA sequencing to study the gene expression profiles of both developing larvae and their caregiving nurses before and after queen removal. By comparing the gene expression profiles of queen-destined versus worker-destined larvae as well as nurses observed feeding these two types of larvae, we identified larval and nurse genes associated with caste development. Of 950 differentially expressed genes associated with caste, 82% were expressed in larvae with putative direct effects on larval caste, and 18% were expressed in nurses with putative indirect effects on caste. Estimated selection coefficients suggest that both nurse and larval genes putatively associated with caste are rapidly evolving, especially those genes associated with worker development. Altogether, our results suggest that indirect effect genes play important roles in both the expression and evolution of socially influenced traits such as caste.

Modeling the surface contamination of dental titanium investment castings.

PubMed

Atwood, R C; Lee, P D; Curtis, R V

2005-02-01

The objective of this study was to develop a computational tool for assisting the design of titanium dental castings with minimal defects and to compare computational simulations with casting experiments. Modeling. An in-house cellular-automata solidification and finite-difference diffusion program was coupled with a commercial casting program and applied to (a) simple geometric wedge models and (b) a 3D-laser scan of a molar crown casting. Experimental. Wedges and molar crowns were hand-waxed and investment cast in commercial purity grade 1 (CP-1) titanium by a commercial dental laboratory. The castings were sectioned and analyzed using light and scanning electron microscopy, X-ray microanalysis, and microhardness testing. In the wedge sample, contamination with impurities (Al, Si), including intermetallic precipitates, was found to extend to a depth ranging from 30 to 120 microm depending on the section thickness and hence the local cooling rate. Microstructural and mechanical (hardness) effects were found to a depth ranging from 80 to 250 microm. The coupled micro/macro model predictions showed reasonable agreement for the pattern of contamination. Dental and medical applications demand close dimensional tolerance and freedom from surface impurities and structural flaws in castings having unique shapes. The ability to predict the structural, mechanical, and chemical changes resulting from the casting process will help to design the casting and post-casting processes to minimize these problems.

46 CFR 59.20-1 - Carbon-steel or alloy-steel castings.

Code of Federal Regulations, 2010 CFR

2010-10-01

... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Castings § 59.20-1 Carbon-steel or alloy-steel castings. Defects in carbon-steel or alloy-steel castings may be repaired by welding. The repairs...

46 CFR 59.20-1 - Carbon-steel or alloy-steel castings.

Code of Federal Regulations, 2011 CFR

2011-10-01

... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Castings § 59.20-1 Carbon-steel or alloy-steel castings. Defects in carbon-steel or alloy-steel castings may be repaired by welding. The repairs...

46 CFR 59.20-1 - Carbon-steel or alloy-steel castings.

Code of Federal Regulations, 2013 CFR

2013-10-01

... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Castings § 59.20-1 Carbon-steel or alloy-steel castings. Defects in carbon-steel or alloy-steel castings may be repaired by welding. The repairs...

46 CFR 59.20-1 - Carbon-steel or alloy-steel castings.

Code of Federal Regulations, 2012 CFR

2012-10-01

... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Castings § 59.20-1 Carbon-steel or alloy-steel castings. Defects in carbon-steel or alloy-steel castings may be repaired by welding. The repairs...

46 CFR 59.20-1 - Carbon-steel or alloy-steel castings.

Code of Federal Regulations, 2014 CFR

2014-10-01

... BOILERS, PRESSURE VESSELS AND APPURTENANCES Welding Repairs to Castings § 59.20-1 Carbon-steel or alloy-steel castings. Defects in carbon-steel or alloy-steel castings may be repaired by welding. The repairs...

Y-chromosomal insights into the genetic impact of the caste system in India.

PubMed

Zerjal, Tatiana; Pandya, Arpita; Thangaraj, Kumarasamy; Ling, Edmund Y S; Kearley, Jennifer; Bertoneri, Stefania; Paracchini, Silvia; Singh, Lalji; Tyler-Smith, Chris

2007-03-01

The caste system has persisted in Indian Hindu society for around 3,500 years. Like the Y chromosome, caste is defined at birth, and males cannot change their caste. In order to investigate the genetic consequences of this system, we have analysed male-lineage variation in a sample of 227 Indian men of known caste, 141 from the Jaunpur district of Uttar Pradesh and 86 from the rest of India. We typed 131 Y-chromosomal binary markers and 16 microsatellites. We find striking evidence for male substructure: in particular, Brahmins and Kshatriyas (but not other castes) from Jaunpur each show low diversity and the predominance of a single distinct cluster of haplotypes. These findings confirm the genetic isolation and drift within the Jaunpur upper castes, which are likely to result from founder effects and social factors. In the other castes, there may be either larger effective population sizes, or less strict isolation, or both.

Metallic Fuel Casting Development and Parameter Optimization Simulations

DOE Office of Scientific and Technical Information (OSTI.GOV)

R.S. Fielding; J. Crapps; C. Unal

One of the advantages of metallic fuel is the abilility to cast the fuel slugs to near net shape with little additional processing. However, the high aspect ratio of the fuel is not ideal for casting. EBR-II fuel was cast using counter gravity injection casting (CGIC) but, concerns have been raised concerning the feasibility of this process for americium bearing alloys. The Fuel Cycle Research and Development program has begun developing gravity casting techniques suitable for fuel production. Compared to CGIC gravity casting does not require a large heel that then is recycled, does not require application of a vacuummore » during melting, and is conducive to re-usable molds. Development has included fabrication of two separate benchscale, approximately 300 grams, systems. To shorten development time computer simulations have been used to ensure mold and crucible designs are feasible and to identify which fluid properties most affect casting behavior and therefore require more characterization.« less

Computational Multi-Scale Modeling of the Microstructure and Segregation of Cast Mg Alloys at Low Superheat

NASA Astrophysics Data System (ADS)

Nastac, Laurentiu; El-Kaddah, Nagy

It is well known that casting at low superheat has a strong influence on the solidification structures of the cast alloy. Recent studies on casting magnesium AZ alloys at low superheat using the Magnetic Suspension Melting (MSM) process have shown that the cast alloy exhibit a fine globular grain structure, and the grain size depend on the cooling rate. This paper describes a stochastic mesoscopic model for predicting the grain structure and segregation in cast alloys at low superheat. This model was applied to predict the globular solidification morphology and solute redistribution of Al in cast Mg AZ31B alloy at different cooling rates. The predictions were found to be in good agreement with the observed grain structure and Al segregation. This makes the model a very useful tool for optimizing the solidification structure of cast magnesium alloys.

Casting Of Multilayer Ceramic Tapes

NASA Technical Reports Server (NTRS)

Collins, Earl R., Jr.

1991-01-01

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

'Fast cast' and 'needle Tenotomy' protocols with the Ponseti method to improve clubfoot management in Bangladesh.

PubMed

Evans, Angela; Chowdhury, Mamun; Rana, Sohel; Rahman, Shariar; Mahboob, Abu Hena

2017-01-01

The management of congenital talipes equino varus ( clubfoot deformity ) has been transformed in the last 20 years as surgical correction has been replaced by the non-surgical Ponseti method. The Ponseti method, consists of corrective serial casting followed by maintenance bracing, and has been repeatedly demonstrated to give best results - regarded as the 'gold standard' treatment for paediatric clubfoot. To develop the study protocol Level 2 evidence was used to modify the corrective casting phase of the Ponseti method in children aged up to 12 months. Using Level 4 evidence, the percutaneous Achilles tenotomy (PAT) was performed using a 19-gauge needle instead of a scalpel blade, a technique found to reduce bleeding and scarring. A total of 123 children participated in this study; 88 male, 35 female. Both feet were affected in 67 cases, left only in 22 cases, right only in 34 cases. Typical clubfeet were found in 112/123 cases, six atypical, five syndromic. The average age at first cast was 51 days (13-240 days).The average number of casts applied was five (2-10 casts). The average number of days between the first cast and brace was 37.8 days (10-122 days), including 21 days in a post-PAT cast. Hence, average time of corrective casts was 17 days.Parents preferred the reduced casting time, and were less concerned about unseen skin wounds.PAT was performed in 103/123 cases, using the needle technique. All post tenotomy casts were in situ for three weeks. Minor complications occurred in seven cases - four cases had skin lesions, three cases disrupted casting phase. At another site, 452 PAT were performed using the needle technique. The 'fast cast' protocol Ponseti casting was successfully used in infants aged less than 8 months. Extended manual manipulation of two minutes was the essential modification. Parents preferred the faster treatment phase, and ability to closer observe the foot and skin. The treating physiotherapists preferred the 'fast cast' protocol, achieving better correction with less complication. The needle technique for PAT is a further improvement for the Ponseti method.

Genetic affinities among the lower castes and tribal groups of India: inference from Y chromosome and mitochondrial DNA.

PubMed

Thanseem, Ismail; Thangaraj, Kumarasamy; Chaubey, Gyaneshwer; Singh, Vijay Kumar; Bhaskar, Lakkakula V K S; Reddy, B Mohan; Reddy, Alla G; Singh, Lalji

2006-08-07

India is a country with enormous social and cultural diversity due to its positioning on the crossroads of many historic and pre-historic human migrations. The hierarchical caste system in the Hindu society dominates the social structure of the Indian populations. The origin of the caste system in India is a matter of debate with many linguists and anthropologists suggesting that it began with the arrival of Indo-European speakers from Central Asia about 3500 years ago. Previous genetic studies based on Indian populations failed to achieve a consensus in this regard. We analysed the Y-chromosome and mitochondrial DNA of three tribal populations of southern India, compared the results with available data from the Indian subcontinent and tried to reconstruct the evolutionary history of Indian caste and tribal populations. No significant difference was observed in the mitochondrial DNA between Indian tribal and caste populations, except for the presence of a higher frequency of west Eurasian-specific haplogroups in the higher castes, mostly in the north western part of India. On the other hand, the study of the Indian Y lineages revealed distinct distribution patterns among caste and tribal populations. The paternal lineages of Indian lower castes showed significantly closer affinity to the tribal populations than to the upper castes. The frequencies of deep-rooted Y haplogroups such as M89, M52, and M95 were higher in the lower castes and tribes, compared to the upper castes. The present study suggests that the vast majority (> 98%) of the Indian maternal gene pool, consisting of Indio-European and Dravidian speakers, is genetically more or less uniform. Invasions after the late Pleistocene settlement might have been mostly male-mediated. However, Y-SNP data provides compelling genetic evidence for a tribal origin of the lower caste populations in the subcontinent. Lower caste groups might have originated with the hierarchical divisions that arose within the tribal groups with the spread of Neolithic agriculturalists, much earlier than the arrival of Aryan speakers. The Indo-Europeans established themselves as upper castes among this already developed caste-like class structure within the tribes.

Genetic affinities among the lower castes and tribal groups of India: inference from Y chromosome and mitochondrial DNA

PubMed Central

Thanseem, Ismail; Thangaraj, Kumarasamy; Chaubey, Gyaneshwer; Singh, Vijay Kumar; Bhaskar, Lakkakula VKS; Reddy, B Mohan; Reddy, Alla G; Singh, Lalji

2006-01-01

Background India is a country with enormous social and cultural diversity due to its positioning on the crossroads of many historic and pre-historic human migrations. The hierarchical caste system in the Hindu society dominates the social structure of the Indian populations. The origin of the caste system in India is a matter of debate with many linguists and anthropologists suggesting that it began with the arrival of Indo-European speakers from Central Asia about 3500 years ago. Previous genetic studies based on Indian populations failed to achieve a consensus in this regard. We analysed the Y-chromosome and mitochondrial DNA of three tribal populations of southern India, compared the results with available data from the Indian subcontinent and tried to reconstruct the evolutionary history of Indian caste and tribal populations. Results No significant difference was observed in the mitochondrial DNA between Indian tribal and caste populations, except for the presence of a higher frequency of west Eurasian-specific haplogroups in the higher castes, mostly in the north western part of India. On the other hand, the study of the Indian Y lineages revealed distinct distribution patterns among caste and tribal populations. The paternal lineages of Indian lower castes showed significantly closer affinity to the tribal populations than to the upper castes. The frequencies of deep-rooted Y haplogroups such as M89, M52, and M95 were higher in the lower castes and tribes, compared to the upper castes. Conclusion The present study suggests that the vast majority (>98%) of the Indian maternal gene pool, consisting of Indio-European and Dravidian speakers, is genetically more or less uniform. Invasions after the late Pleistocene settlement might have been mostly male-mediated. However, Y-SNP data provides compelling genetic evidence for a tribal origin of the lower caste populations in the subcontinent. Lower caste groups might have originated with the hierarchical divisions that arose within the tribal groups with the spread of Neolithic agriculturalists, much earlier than the arrival of Aryan speakers. The Indo-Europeans established themselves as upper castes among this already developed caste-like class structure within the tribes. PMID:16893451

It is not just comfort: waterproof casting increases physical functioning in children with minimally angulated distal radius fractures.

PubMed

Silva, Mauricio; Avoian, Tigran; Warnock, Robert Sean; Sadlik, Gal; Ebramzadeh, Edward

2017-09-01

Waterproof casting has been reported to increase patient comfort and satisfaction, and decrease skin irritation. There are no available data on the influence of waterproof casting materials on physical function in pediatric patients. Our aim was to determine whether the use of waterproof casting would result in faster recovery of physical function while maintaining similar clinical outcomes as those obtained with nonwaterproof materials. Twenty-six children with nonangulated or minimally angulated distal radius fractures were assigned randomly to initially receive a short-arm cast made of one of two optional materials: a hybrid mesh material with a waterproof lining or fiberglass with a nonwaterproof skin protector. Two weeks later, the initial cast was removed and replaced with a short-arm cast made of the alternative option. We compared the rate of fracture displacement, physical function, pain, skin changes, itchiness, and patient satisfaction. No evidence of displacement was found in either group. The mean Activities Scale for Kids - Performance (ASK-P) (physical function) score was 10% higher during the period of time when a waterproof cast was used (P=0.04). When a waterproof cast was used during the first 2 weeks of treatment, the mean total ASK-P scores were 23% higher than that when a nonwaterproof one was used during the same period of time (P=0.003). Patients who received a waterproof cast as the initial treatment reported lower functional scores overall and in almost every domain of the ASK-P once they were in a nonwaterproof one; similarly, those who received a nonwaterproof cast as the initial treatment reported higher functional scores overall and in every domain of the ASK-P once they were in a waterproof cast. Compared with a nonwaterproof cast, the use of waterproof casting resulted in comparable levels of pain, itchiness, skin irritability, and overall patient satisfaction. The results of this randomized, cross-over trial suggest that the use of waterproof casting material for the treatment of nondisplaced or minimally displaced distal radius fractures in children can result in a faster recovery of physical function, while providing comparable stability, pain, itchiness, skin irritability, and overall patient satisfaction. II.

Concise Associated Symptoms Tracking scale: a brief self-report and clinician rating of symptoms associated with suicidality.

PubMed

Trivedi, Madhukar H; Wisniewski, Stephen R; Morris, David W; Fava, Maurizio; Kurian, Benji T; Gollan, Jackie K; Nierenberg, Andrew A; Warden, Diane; Gaynes, Bradley N; Luther, James F; Rush, A John

2011-06-01

US Food and Drug Administration (FDA) warnings recommend monitoring negative symptoms associated with the initiation of antidepressant medications as these symptoms may interfere with full recovery and pose safety concerns. There is currently no brief, reliable rating instrument for assessing treatment-emergent, negative symptoms. We evaluated the psychometric properties of 2 versions of the newly developed 17-item Concise Associated Symptom Tracking (CAST) scale, the CAST Clinician Rating (CAST-C) and CAST Self-Rated (CAST-SR), which are brief instruments designed to measure the 5 relevant associated symptom domains (irritability, anxiety, mania, insomnia, and panic). The study enrolled 265 outpatients with major depressive disorder (MDD), from July 2007 through February 2008, into an 8-week, open-label trial with a selective serotonin reuptake inhibitor. Diagnosis of MDD was determined by the Psychiatric Diagnostic Screening questionnaire and an MDD checklist based on DSM-IV-TR criteria. Suicidality (suicidal ideation with associated behaviors) is 1 of 9 symptoms of MDD (depressed mood, loss of interest, appetite or weight change, sleep disturbance, reduced concentration or indecisiveness, fatigue or decreased energy, psychomotor agitation or retardation, feelings of worthlessness or excessive guilt). Psychometric evaluations were conducted on both versions of the CAST. Cronbach α was .80 (CAST-C) and .81 (CAST-SR). Factor analysis identified 5 factors for each scale: (1) irritability, (2) anxiety, (3) mania, (4) insomnia, and (5) panic. When the item that cross-loaded on 2 factors was eliminated, the 16-item solution had a better goodness of fit (CAST-C: 0.90 vs 0.87; CAST-SR: 0.88 vs 0.84). Cronbach α for the 16-item versions was .77 (CAST-C) and .78 (CAST-SR). The 5 associated CAST symptom domains correlated well with other standard measures of these domains. The 16-item CAST-C and CAST-SR demonstrated excellent psychometric properties. These are potentially useful measures for monitoring treatment-emergent negative symptoms associated with antidepressants, as recommended by the FDA. Clinicaltrials.gov Identifier: NCT00532103. © Copyright 2011 Physicians Postgraduate Press, Inc.

Women's health in a rural community in Kerala, India: do caste and socioeconomic position matter?

PubMed Central

Mohindra, K S; Haddad, Slim; Narayana, D

2006-01-01

Objectives To examine the social patterning of women's self‐reported health status in India and the validity of the two hypotheses: (1) low caste and lower socioeconomic position is associated with worse reported health status, and (2) associations between socioeconomic position and reported health status vary across castes. Design Cross‐sectional household survey, age‐adjusted percentages and odds ratios, and multilevel multinomial logistic regression models were used for analysis. Setting A panchayat (territorial decentralised unit) in Kerala, India, in 2003. Participants 4196 non‐elderly women. Outcome measures Self‐perceived health status and reported limitations in activities in daily living. Results Women from lower castes (scheduled castes/scheduled tribes (SC/ST) and other backward castes (OBC) reported a higher prevalence of poor health than women from forward castes. Socioeconomic inequalities were observed in health regardless of the indicators, education, women's employment status or household landholdings. The multilevel multinomial models indicate that the associations between socioeconomic indicators and health vary across caste. Among SC/ST and OBC women, the influence of socioeconomic variables led to a “magnifying” effect, whereas among forward caste women, a “buffering” effect was found. Among lower caste women, the associations between socioeconomic factors and self‐assessed health are graded; the associations are strongest when comparing the lowest and highest ratings of health. Conclusions Even in a relatively egalitarian state in India, there are caste and socioeconomic inequalities in women's health. Implementing interventions that concomitantly deal with caste and socioeconomic disparities will likely produce more equitable results than targeting either type of inequality in isolation. PMID:17108296

Improving Metal Casting Process

NASA Technical Reports Server (NTRS)

1998-01-01

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

Numerical simulation of the casting process of titanium tooth crowns and bridges.

PubMed

Wu, M; Augthun, M; Wagner, I; Sahm, P R; Spiekermann, H

2001-06-01

The objectives of this paper were to simulate the casting process of titanium tooth crowns and bridges; to predict and control porosity defect. A casting simulation software, MAGMASOFT, was used. The geometry of the crowns with fine details of the occlusal surface were digitized by means of laser measuring technique, then converted and read in the simulation software. Both mold filling and solidification were simulated, the shrinkage porosity was predicted by a "feeding criterion", and the gas pore sensitivity was studied based on the mold filling and solidification simulations. Two types of dental prostheses (a single-crown casting and a three-unit-bridge) with various sprue designs were numerically "poured", and only one optimal design for each prosthesis was recommended for real casting trial. With the numerically optimized design, real titanium dental prostheses (five replicas for each) were made on a centrifugal casting machine. All the castings endured radiographic examination, and no porosity was detected in the cast prostheses. It indicates that the numerical simulation is an efficient tool for dental casting design and porosity control. Copyright 2001 Kluwer Academic Publishers

A Comparative Study of Hot Deformation Behaviors for Sand Casting and Centrifugal Casting Q235B Flange Blanks

NASA Astrophysics Data System (ADS)

Qin, Fangcheng; Li, Yongtang; Ju, Li

2017-03-01

Hot compression tests of sand casting and centrifugal casting Q235B flange blanks were performed at strain rate range of 0.01-5 s-1 and temperature range of 850-1,150 °C. The evolutions of microstructure and texture were revealed. The constitutive models based on Arrhenius constitutive modeling were proposed by considering the effects of strain on material constants. The results show that recrystallization in centrifugal casting Q235B is more apparent than that in sand casting, resulting in the finer grains and lower flow stress for centrifugal casting Q235B. The intensities of textures slightly weaken with the increase of temperature. At 1,050 °C and 5 s-1, the textures of sand casting are characterized by strong {001}<100> and {001}<110>, which are related with severe deformation, while the textures of centrifugal casting are composed of {110}<110> and {111}<112>, which are related with dynamic recovery and shear deformation. A good agreement between the predicted and experimental flow stress is achieved and demonstrates that the proposed constitutive models are reliable.

Development of a new casting method to fabricate U–Zr alloy containing minor actinides

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jong Hwan Kim; Hoon Song; Hyung Tae Kim

2014-01-01

Metal fuel slugs of U–Zr alloys for a sodium-cooled fast reactor (SFR) have conventionally been fabricated using an injection casting method. However, casting alloys containing volatile radioactive constituents, such as Am, are problematic in a conventional injection casting method. As an alternative fabrication method, low pressure gravity casting has been developed. Casting soundness, microstructural characteristics, alloying composition, density, and fuel losses were evaluated for the following as-cast fuel slugs: U–10 wt% Zr, U–10 wt% Zr–5 wt% RE, and U–10 wt% Zr–5 wt% RE–5 wt% Mn. The U and Zr contents were uniform throughout the matrix, and impurities such as oxyen,more » carbon, and nitrogen satisfied the specification of total impurities less than 2,000 ppm. The appearance of the fuel slugs was generally sound, and the internal integrity was shown to be satisfactory based on gamma-ray radiography. In a volatile surrogate casting test, the U–Zr–RE–Mn fuel slug showed that nearly all of the manganese was retained when casting was done under an inert atmosphere.« less

The perception of 3-D shape from shadows cast onto curved surfaces.

PubMed

Norman, J Farley; Lee, Young-lim; Phillips, Flip; Norman, Hideko F; Jennings, L RaShae; McBride, T Ryan

2009-05-01

In a natural environment, cast shadows abound. Objects cast shadows both upon themselves and upon background surfaces. Previous research on the perception of 3-D shape from cast shadows has only examined the informativeness of shadows cast upon flat background surfaces. In outdoor environments, however, background surfaces often possess significant curvature (large rocks, trees, hills, etc.), and this background curvature distorts the shape of cast shadows. The purpose of this study was to determine the extent to which observers can "discount" the distorting effects of curved background surfaces. In our experiments, observers viewed deforming or static shadows of naturally shaped objects, which were cast upon flat and curved background surfaces. The results showed that the discrimination of 3-D object shape from cast shadows was generally invariant over the distortions produced by hemispherical background surfaces. The observers often had difficulty, however, in identifying the shadows cast onto saddle-shaped background surfaces. The variations in curvature which occur in different directions on saddle-shaped background surfaces cause shadow distortions that lead to difficulties in object recognition and discrimination.

Numerical simulation of the solidification microstructure of a 17-4PH stainless steel investment casting and its experimental verification

NASA Astrophysics Data System (ADS)

Li, You Yun; Tsai, DeChang; Hwang, Weng Sing

2008-06-01

The purpose of this study is to develop a technique of numerically simulating the microstructure of 17-4PH (precipitation hardening) stainless steel during investment casting. A cellular automation (CA) algorithm was adopted to simulate the nucleation and grain growth. First a calibration casting was made, and then by comparing the microstructures of the calibration casting with those simulated using different kinetic growth coefficients (a2, a3) in CA, the most appropriate set of values for a2 and a3 would be obtained. Then, this set of values was applied to the microstructure simulation of a separate casting, where the casting was actually made. Through this approach, this study has arrived at a set of growth kinetic coefficients from the calibration casting: a2 is 2.9 × 10-5, a3 is 1.49 × 10-7, which is then used to predict the microstructure of the other test casting. Consequently, a good correlation has been found between the microstructure of actual 17-4PH casting and the simulation result.

Consanguineous marriages and matrimonial distance: a study among three South Indian caste groups.

PubMed

Reddy, P G

1988-12-01

Reddy studies consanguineous marriages and matrimonial distance in 3 castes of Nellore district, Andhra Pradesh, South India. The castes include the well-to-do agricultural caste, the Desuri Kapu; the 2nd, artisan caste in the middle of the hierarchy, the Devanga; and the third caste at the bottom of the social ladder, the Mala. During field work conducted in 1978-1979, prominent elders of the villages were approached; information on the consanguinity of marriage and matrimonial distance was gathered through intensive interviews of both men and women from all the households of the 3 castes. Among the total of 979 marriages, 28.9% occurred within the village, the proportion of intra-village marriages being significantly higher in Nellore taluk than in Sullurpet. The 3 castes overall show little difference in the incidence of intra-village marriages, but there is some within caste regional variation in the incidence of intra-village marriages, the Devanga showing a significantly higher incidence in Nellore than in Sullurpet. Intra-village marriages are more common among consanguineous couples (41.5%) than among non-consanguineous (18.3%), a highly significant excess in each of the caste groups. In short, Reddy concludes that intra-village marriages are more common among consanguineous couples than non-consanguineous, and mean matrimonial distance is also lower.

Caste development and evolution in ants: it's all about size.

PubMed

Trible, Waring; Kronauer, Daniel J C

2017-01-01

Female ants display a wide variety of morphological castes, including workers, soldiers, ergatoid (worker-like) queens and queens. Alternative caste development within a species arises from a variable array of genetic and environmental factors. Castes themselves are also variable across species and have been repeatedly gained and lost throughout the evolutionary history of ants. Here, we propose a simple theory of caste development and evolution. We propose that female morphology varies as a function of size, such that larger individuals possess more queen-like traits. Thus, the diverse mechanisms that influence caste development are simply mechanisms that affect size in ants. Each caste-associated trait has a unique relationship with size, producing a phenotypic space that permits some combinations of worker- and queen-like traits, but not others. We propose that castes are gained and lost by modifying the regions of this phenotypic space that are realized within a species. These modifications can result from changing the size-frequency distribution of individuals within a species, or by changing the association of tissue growth and size. We hope this synthesis will help unify the literature on caste in ants, and facilitate the discovery of molecular mechanisms underlying caste development and evolution. © 2017. Published by The Company of Biologists Ltd.

A new method to acquire 3-D images of a dental cast

NASA Astrophysics Data System (ADS)

Li, Zhongke; Yi, Yaxing; Zhu, Zhen; Li, Hua; Qin, Yongyuan

2006-01-01

This paper introduced our newly developed method to acquire three-dimensional images of a dental cast. A rotatable table, a laser-knife, a mirror, a CCD camera and a personal computer made up of a three-dimensional data acquiring system. A dental cast is placed on the table; the mirror is installed beside the table; a linear laser is projected to the dental cast; the CCD camera is put up above the dental cast, it can take picture of the dental cast and the shadow in the mirror; while the table rotating, the camera records the shape of the laser streak projected on the dental cast, and transmit the data to the computer. After the table rotated one circuit, the computer processes the data, calculates the three-dimensional coordinates of the dental cast's surface. In data processing procedure, artificial neural networks are enrolled to calibrate the lens distortion, map coordinates form screen coordinate system to world coordinate system. According to the three-dimensional coordinates, the computer reconstructs the stereo image of the dental cast. It is essential for computer-aided diagnosis and treatment planning in orthodontics. In comparison with other systems in service, for example, laser beam three-dimensional scanning system, the characteristic of this three-dimensional data acquiring system: a. celerity, it casts only 1 minute to scan a dental cast; b. compact, the machinery is simple and compact; c. no blind zone, a mirror is introduced ably to reduce blind zone.

Obtaining of High Cr Content Cast Iron Materials

NASA Astrophysics Data System (ADS)

Florea, C.; Bejinariu, C.; Carcea, I.; Cimpoesu, N.; Chicet, D. L.; Savin, C.

2017-06-01

We have obtained, through the classic casting process, 3 highly chromium-based experimental alloys proposed for replacing the FC 250 classical cast iron in braking applications. Casting was carried out in an induction furnace and cast into moulds made of KALHARTZ 8500 resin casting mixture and HARTER hardener at SC RanCon SRL Iasi. It is known that the microstructure of the cast iron is a combination of martensite with a small amount of residual austenite after the heat treatment of the ingot. In the case of high-alloy chromium alloys, the performance of the material is due to the presence of M7C3 carbides distributed in the iron matrix Resistance to machining and deformation is based on alloy composition and microstructure, while abrasion resistance will depend on properties and wear conditions.

Possibility of reconstruction of dental plaster cast from 3D digital study models

PubMed Central

2013-01-01

Objectives To compare traditional plaster casts, digital models and 3D printed copies of dental plaster casts based on various criteria. To determine whether 3D printed copies obtained using open source system RepRap can replace traditional plaster casts in dental practice. To compare and contrast the qualities of two possible 3D printing options – open source system RepRap and commercially available 3D printing. Design and settings A method comparison study on 10 dental plaster casts from the Orthodontic department, Department of Stomatology, 2nd medical Faulty, Charles University Prague, Czech Republic. Material and methods Each of 10 plaster casts were scanned by inEos Blue scanner and the printed on 3D printer RepRap [10 models] and ProJet HD3000 3D printer [1 model]. Linear measurements between selected points on the dental arches of upper and lower jaws on plaster casts and its 3D copy were recorded and statistically analyzed. Results 3D printed copies have many advantages over traditional plaster casts. The precision and accuracy of the RepRap 3D printed copies of plaster casts were confirmed based on the statistical analysis. Although the commercially available 3D printing enables to print more details than the RepRap system, it is expensive and for the purpose of clinical use can be replaced by the cheaper prints obtained from RepRap printed copies. Conclusions Scanning of the traditional plaster casts to obtain a digital model offers a pragmatic approach. The scans can subsequently be used as a template to print the plaster casts as required. Using 3D printers can replace traditional plaster casts primarily due to their accuracy and price. PMID:23721330

Directional migration in the Hindu castes: inferences from mitochondrial, autosomal and Y-chromosomal data.

PubMed

Wooding, Stephen; Ostler, Christopher; Prasad, B V Ravi; Watkins, W Scott; Sung, Sandy; Bamshad, Mike; Jorde, Lynn B

2004-08-01

Genetic, ethnographic, and historical evidence suggests that the Hindu castes have been highly endogamous for several thousand years and that, when movement between castes does occur, it typically consists of females joining castes of higher social status. However, little is known about migration rates in these populations or the extent to which migration occurs between caste groups of low, middle, and high social status. To investigate these aspects of migration, we analyzed the largest collection of genetic markers collected to date in Hindu caste populations. These data included 45 newly typed autosomal short tandem repeat polymorphisms (STRPs), 411 bp of mitochondrial DNA sequence, and 43 Y-chromosomal single-nucleotide polymorphisms that were assayed in more than 200 individuals of known caste status sampled in Andrah Pradesh, in South India. Application of recently developed likelihood-based analyses to this dataset enabled us to obtain genetically derived estimates of intercaste migration rates. STRPs indicated migration rates of 1-2% per generation between high-, middle-, and low-status caste groups. We also found support for the hypothesis that rates of gene flow differ between maternally and paternally inherited genes. Migration rates were substantially higher in maternally than in paternally inherited markers. In addition, while prevailing patterns of migration involved movement between castes of similar rank, paternally inherited markers in the low-status castes were most likely to move into high-status castes. Our findings support earlier evidence that the caste system has been a significant, long-term source of population structuring in South Indian Hindu populations, and that patterns of migration differ between males and females. Copyright 2004 Springer-Verlag

Cyp15F1: a novel cytochrome P450 gene linked to juvenile hormone-dependent caste differention in the termite Reticulitermes flavipes.

PubMed

Tarver, Matthew R; Coy, Monique R; Scharf, Michael E

2012-07-01

Termites are eusocial insects that jointly utilize juvenile hormone (JH), pheromones, and other semiochemicals to regulate caste differentiation and achieve caste homeostasis. Prior EST sequencing from the symbiont-free gut transcriptome of Reticulitermes flavipes unexpectedly revealed a number of unique cytochrome P450 (Cyp) transcripts, including fragments of a Cyp15 family gene (Cyp15F1) with homology to other insect Cyp15s that participate in JH biosynthesis. The present study investigated the role of Cyp15F1 in termite caste polyphenism and specifically tested the hypothesis that it plays a role in JH-dependent caste differentiation. After assembling the full-length Cyp15F1 cDNA sequence, we (i) determined its mRNA tissue expression profile, (ii) investigated mRNA expression changes in response to JH and the caste-regulatory primer pheromones γ-cadinene (CAD) and γ-cadinenal (ALD), and (iii) used RNA interference (RNAi) in combination with caste differentiation bioassays to investigate gene function at the phenotype level. Cyp15F1 has ubiquitous whole-body expression (including gut tissue); is rapidly and sustainably induced from 3 h to 48 h by JH, CAD, and ALD; and functions at least in part by facilitating JH-dependent soldier caste differentiation. These findings provide the second example of a termite caste regulatory gene identified through the use of RNAi, and significantly build upon our understanding of termite caste homeostatic mechanisms. These results also reinforce the concept of environmental caste determination in termites by revealing how primer pheromones, as socioenvironmental factors, can directly influence Cyp15 expression and caste differentiation. © 2012 Wiley Periodicals, Inc.

Energy Saving Melting and Revert Reduction Technology (Energy-SMARRT): Light Metals Permanent Mold Casting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fasoyinu, Yemi

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 alloymore » 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.« less

Multidisciplinary approach to improve the quality of below-knee plaster casting.

PubMed

Williams, John Teudar; Kedrzycki, Marta; Shenava, Yathish

2018-01-01

In our trauma unit, we noted a high rate of incorrectly applied below-knee casts for ankle fractures, in some cases requiring reapplication. This caused significant discomfort and inconvenience for patients and additional burden on plaster-room services. Our aim was to improve the quality of plaster casts and reduce the proportion that needed to be reapplied. Our criteria for plaster cast quality were based on the British Orthopaedic Association Casting Standards (2015) and included neutral (plantargrade) ankle position, adequacy of fracture reduction and rate of cast reapplication. Baseline data collection was performed over a 2-month period by two independent reviewers. After distributing findings and presenting to relevant departments, practical casting sessions with orthopaedic technicians were arranged for the multidisciplinary team responsible for casting. This was later supplemented by new casting guidelines in clinical areas and available online. Postintervention data collection was performed over two separate cycles to assess the effect and permanence of intervention. Data from the preintervention period (n=29) showed median ankle position was 32° plantarflexion (PF), with nine (31%) inadequate reductions and six (20%) backslabs reapplied. Following Plan-Do-Study-Act (PDSA) 1, ankle position was significantly improved (median 25° PF), there were fewer inadequate reductions (12%; 2/17) and a lower rate of reapplication (0%; 0/17). After PDSA 2 (n=16), median ankle position was 21° PF, there was one (6%) inadequate reduction and two (12%) reapplications of casts. Following implementation of plaster training sessions for accident and emergency and junior orthopaedic staff, in addition to publishing guidance and new protocol, there has been a sustained improvement in the quality of below-knee backslabs and fewer cast reapplications. These findings justify continuation and expansion of the current programme to include other commonly applied plaster casts.

Accuracy of ringless casting and accelerated wax-elimination technique: a comparative in vitro study.

PubMed

Prasad, Rahul; Al-Keraif, Abdulaziz Abdullah; Kathuria, Nidhi; Gandhi, P V; Bhide, S V

2014-02-01

The purpose of this study was to determine whether the ringless casting and accelerated wax-elimination techniques can be combined to offer a cost-effective, clinically acceptable, and time-saving alternative for fabricating single unit castings in fixed prosthodontics. Sixty standardized wax copings were fabricated on a type IV stone replica of a stainless steel die. The wax patterns were divided into four groups. The first group was cast using the ringless investment technique and conventional wax-elimination method; the second group was cast using the ringless investment technique and accelerated wax-elimination method; the third group was cast using the conventional metal ring investment technique and conventional wax-elimination method; the fourth group was cast using the metal ring investment technique and accelerated wax-elimination method. The vertical marginal gap was measured at four sites per specimen, using a digital optical microscope at 100× magnification. The results were analyzed using two-way ANOVA to determine statistical significance. The vertical marginal gaps of castings fabricated using the ringless technique (76.98 ± 7.59 μm) were significantly less (p < 0.05) than those castings fabricated using the conventional metal ring technique (138.44 ± 28.59 μm); however, the vertical marginal gaps of the conventional (102.63 ± 36.12 μm) and accelerated wax-elimination (112.79 ± 38.34 μm) castings were not statistically significant (p > 0.05). The ringless investment technique can produce castings with higher accuracy and can be favorably combined with the accelerated wax-elimination method as a vital alternative to the time-consuming conventional technique of casting restorations in fixed prosthodontics. © 2013 by the American College of Prosthodontists.

Efficiency and Safety: The Best Time to Valve a Plaster Cast.

PubMed

Steiner, Samuel R H; Gendi, Kirollos; Halanski, Matthew A; Noonan, Kenneth J

2018-04-18

The act of applying, univalving, and spreading a plaster cast to accommodate swelling is commonly performed; however, cast saws can cause thermal and/or abrasive injury to the patient. This study aims to identify the optimal time to valve a plaster cast so as to reduce the risk of cast-saw injury and increase spreading efficiency. Plaster casts were applied to life-sized pediatric models and were univalved at set-times of 5, 8, 12, or 25 minutes. Outcome measures included average and maximum force applied during univalving, blade-to-skin touches, cut time, force needed to spread, number of spread attempts, spread completeness, spread distance, saw blade temperature, and skin surface temperature. Casts allowed to set for ≥12 minutes had significantly fewer blade-to-skin touches compared with casts that set for <12 minutes (p < 0.001). For average and maximum saw blade force, no significant difference was observed between individual set-times. However, in a comparison of the shorter group (<12 minutes) and the longer group (≥12 minutes), the longer group had a higher average force (p = 0.009) but a lower maximum force (p = 0.036). The average temperature of the saw blade did not vary between groups. The maximum force needed to "pop," or spread, the cast was greater for the 5-minute and 8-minute set-times. Despite requiring more force to spread the cast, 0% of attempts at 5 minutes and 54% of attempts at 8 minutes were successful in completely spreading the cast, whereas 100% of attempts at 12 and 25 minutes were successful. The spread distance was greatest for the 12-minute set-time at 5.7 mm. Allowing casts to set for 12 minutes is associated with decreased blade-to-skin contact, less maximum force used with the saw blade, and a more effective spread. Adherence to the 12-minute interval could allow for fewer cast-saw injuries and more effective spreading.

Effect of dental technician disparities on the 3-dimensional accuracy of definitive casts.

PubMed

Emir, Faruk; Piskin, Bulent; Sipahi, Cumhur

2017-03-01

Studies that evaluated the effect of dental technician disparities on the accuracy of presectioned and postsectioned definitive casts are lacking. The purpose of this in vitro study was to evaluate the accuracy of presectioned and postsectioned definitive casts fabricated by different dental technicians by using a 3-dimensional computer-aided measurement method. An arch-shaped metal master model consisting of 5 abutments resembling prepared mandibular incisors, canines, and first molars and with a 6-degree total angle of convergence was designed and fabricated by computer-aided design and computer-aided manufacturing (CAD-CAM) technology. Complete arch impressions were made (N=110) from the master model, using polyvinyl siloxane (PVS) and delivered to 11 dental technicians. Each technician fabricated 10 definitive casts with dental stone, and the obtained casts were numbered. All casts were sectioned, and removable dies were obtained. The master model and the presectioned and postsectioned definitive casts were digitized with an extraoral scanner, and the virtual master model and virtual presectioned and postsectioned definitive casts were obtained. All definitive casts were compared with the master model by using computer-aided measurements, and the 3-dimensional accuracy of the definitive casts was determined with best fit alignment and represented in color-coded maps. Differences were analyzed using univariate analyses of variance, and the Tukey honest significant differences post hoc tests were used for multiple comparisons (α=.05). The accuracy of presectioned and postsectioned definitive casts was significantly affected by dental technician disparities (P<.001). The largest dimensional changes were detected in the anterior abutments of both of the definitive casts. The changes mostly occurred in the mesiodistal dimension (P<.001). Within the limitations of this in vitro study, the accuracy of presectioned and postsectioned definitive casts is susceptible to dental technician differences. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

7 CFR 1160.607 - Tabulation of ballots.

Code of Federal Regulations, 2010 CFR

2010-01-01

... referendum agent shall verify the validity of all ballots cast in accordance with the instructions and... ballots cast, including the disqualified ballots, shall be ascertained. The number of ballots cast approving, the number of ballots cast disapproving, and the pounds of fluid milk products distributed during...

75 FR 23295 - Iron Construction Castings From Brazil, Canada, and China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-03

... ``heavy'' iron construction castings from Brazil, the antidumping duty order on ``heavy'' iron... the countervailing duty order on ``heavy'' iron construction castings from Brazil, the antidumping duty order on ``heavy'' iron construction castings from Canada, and the antidumping duty orders on iron...

Vertical marginal gap evaluation of conventional cast and computer numeric controlled-milled titanium full-arch implant-supported frameworks.

PubMed

Alfadda, Sara A

2014-01-01

To use a novel approach to measure the amount of vertical marginal gap in computer numeric controlled (CNC)-milled titanium frameworks and conventional cast frameworks. Ten cast frameworks were fabricated on the mandibular master casts of 10 patients. Then, 10 CNC-milled titanium frameworks were fabricated by laser scanning the cast frameworks. The vertical marginal gap was measured and analyzed using the Contura-G2 coordinate measuring machine and special computer software. The CNC-milled titanium frameworks showed an overall reduced mean vertical gap compared with the cast frameworks in all five analogs. This difference was highly statistically significant in the distal analogs. The largest mean gap in the cast framework was recorded in the most distal analogs, and the least amount was in the middle analog. Neither of the two types of frameworks provided a completely gap-free superstructure. The CNCmilled titanium frameworks showed a significantly smaller vertical marginal gap than the cast frameworks.

Emulsion based cast booster - a priming system

DOE Office of Scientific and Technical Information (OSTI.GOV)

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

2005-07-01

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

Y-chromosomal insights into the genetic impact of the caste system in India

PubMed Central

Zerjal, Tatiana; Pandya, Arpita; Thangaraj, Kumarasamy; Ling, Edmund Y. S.; Kearley, Jennifer; Bertoneri, Stefania; Paracchini, Silvia; Singh, Lalji; Tyler-Smith, Chris

2008-01-01

The caste system has persisted in Indian Hindu society for around 3,500 years. Like the Y chromosome, caste is defined at birth, and males cannot change their caste. In order to investigate the genetic consequences of this system, we have analysed male-lineage variation in a sample of 227 Indian men of known caste, 141 from the Jaunpur district of Uttar Pradesh and 86 from the rest of India. We typed 131 Y-chromosomal binary markers and 16 microsatellites. We find striking evidence for male substructure: in particular, Brahmins and Kshatriyas (but not other castes) from Jaunpur each show low diversity and the predominance of a single distinct cluster of haplotypes. These findings confirm the genetic isolation and drift within the Jaunpur upper castes, which are likely to result from founder effects and social factors. In the other castes, there may be either larger effective population sizes, or less strict isolation, or both. PMID:17075717

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

PubMed

Patil, Rajan R

2014-01-01

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

Direct Cast U-6Nb – 2017 Progress on Cylindrical Castings

DOE Office of Scientific and Technical Information (OSTI.GOV)

Aikin, Jr., Robert M.

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.more » 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.« less

Three solutions to a single problem: alternative casting frames for treating infantile idiopathic scoliosis.

PubMed

Halanski, Matthew A; Harper, Benjamin L; Cassidy, Jeffry A; Crawford, Haemish A

2013-07-01

This is a technique article discussing 3 alternative frames for casting children with infantile scoliosis. To provide surgeons with alternatives to expensive specialized casting tables to allow local treatment of these children utilizing readily available materials present at most institutions. Casting for infantile scoliosis has become more popular as reports have shown promising results with this technique without the morbidity and complications associated with more invasive procedures. However, without a specialized casting table, treating these patients has been limited to a few centers throughout the country often causing patients to travel large distances to receive care. Three different alternatives to commercially available casting frames are presented. Requirements, setup, and techniques are discussed. Each surgeon has had success with each of these frames. These provide adequate support and traction while allowing enough access to the trunk to apply a well-molded cast. Cotrel/Metha casting for infantile scoliosis can be accomplished without a specialized table using commonly available equipment.

Development of the Electromagnetic Continuous Casting Technology for of Magnesium Alloys

NASA Astrophysics Data System (ADS)

Park, Joon-Pyo; Kim, Myoung-Gyun; Kim, Jong-Ho; Lee, Gyu-Chang

Currently, magnesium billets produced by ingot casting or direct chill casting process, result in low-quality surfaces and low productivity, Continuous casting technology to solve these problem has not only high-quality surface billets with fine-grained and homogeneous microstructure but also cost down. The latent heat of fusion per weight (J/g) of magnesium is similar to other metals, however, considering the heat emitted to the mold surface during continuous casting in meniscus region and converting it to the latent heat of fusion per volume, magnesium will be rapidly solidified in the mold during continuous casting, which induces subsequent surface defect formation. In this study, electromagnetic casting and stirring (EMC and EMS) techniques are proposed to control solidification process conveniently by compensating the low latent heat of solidification by volume and to fabricate magnesium billet with high-quality surface. This technique was extended to large scale billets up to 300 mm diameter and continuous casting was successfully conducted. Then magnesium billet was used for the fabrication of prototype automobile pulley.

Caste-based social inequalities and childhood anemia in India: results from the National Family Health Survey (NFHS) 2005-2006.

PubMed

Vart, Priya; Jaglan, Ajay; Shafique, Kashif

2015-06-05

Caste is one of the traditional measures of social segregation in India and differs from other indicators as it is both, endogamous and hereditary. Evidence suggests that belonging to lower castes exposes one to social inequalities and affects health adversely. We examined the association of caste with childhood anemia in India and explored the effect modifying role of adult education and household wealth. A cross-sectional analysis of National Family Health Survey (NFHS) data of 43,484 children aged 6-59 months was performed. Poisson regression analysis was conducted to study the association between caste and childhood anemia accounting for various maternal, child, and household related variables. Caste was categorized as "other caste" (least disadvantageous), "other backward caste", "scheduled tribe" and "scheduled caste" (most disadvantageous). Anemia was defined as mild (hemoglobin level 7-11 g/dL), moderate (hemoglobin level 5-7 g/dL) and severe (hemoglobin level <5 g/dL). We found that children in scheduled caste had higher risk of having anemia [mild anemia: RR = 1.10, 95% CI = 1.05-1.15; moderate anemia: RR = 1.19, 95% CI = 1.14-1.24; severe anemia: RR = 1.87, 95% CI = 1.51-2.31] after accounting for child, maternal and household covariates including adult education and household wealth. The interaction of caste with adult education and household wealth was not statistically significant for any level of anemia. Sensitivity analyses for children born to mothers of age ≥ 18 years at first child birth and body mass index (BMI) ≥ 18.5 kg/m(2), resulted in similar findings. Caste is an independent determinant of childhood anemia in India. The level of adult education and household wealth did not modify the association between caste and childhood anemia. The findings may be used for countering childhood anemia and it may be beneficial to target future public health actions towards disadvantageous castes in India.

Oral Sucrose for Pain Relief During Clubfoot Casting: A Double-Blinded Randomized Controlled Trial.

PubMed

Milbrandt, Todd; Kryscio, Richard; Muchow, Ryan; Walker, Janet; Talwalkar, Vishwas; Iwinski, Henry

2016-09-15

Idiopathic clubfoot treatment is treated by manipulation and casting utilizing the Ponseti technique which can make the infant fussy and irritable. The goal of this study was to determine which intervention could decrease this pain response in infants undergoing Ponseti casting for idiopathic clubfeet. Our hypothesis was that the administration of oral sucrose solution or milk would be the most effective in accomplishing that goal. We conducted a double-blinded randomized controlled trial at a tertiary pediatric orthopaedic center on 33 children (average age=17.94 d; SD=20.51 d) undergoing clubfoot manipulation and casting and their guardians. Each cast was considered a new event and was randomized to an oral 20% sucrose solution (S), water (W), or milk (M) in a bottle (breast or nonbreast). We assessed the Neonatal Infant Pain Scale (NIPS), heart rate, and oxygen saturation before, during, and after the casting. A total of 131 casts were randomized and 118 analyzed (37 M, 42 S, 39 W). Each child underwent an average of 3.97 casts (SD=1.74). There were no significant differences seen between the groups before casting in their mean NIPS score (M=2.2; SD=2.38, S=1.84, SD=2.18, W=1.61, SD=2.12). However during casting, mean NIPS score for both milk, 0.91 (SD=1.26, P=0.0005) and sucrose, 0.64 (SD=1.27, P<0.0001) were significantly less than water, 2.27 (SD=2.03) but not different from each other (P=0.33). Postcasting, the sucrose NIPS score, 0.69 (SD=1.53) continued to be significantly less than milk, 2.11 (SD=2.37, P=0.0065. There was no correlation between heart rate or oxygen saturation and NIPS. Sucrose solution and milk during Ponseti casting and manipulation were effective in decreasing the pain response in children undergoing manipulation and casting for clubfeet. The sucrose solution administration continued the pain relief into the postcasting period. In addition to the benefits of improving the patient experience during casting, a less irritable child may result in better casting. Level 1 evidence.

The role of serial casting in early-onset scoliosis (EOS).

PubMed

Baulesh, David M; Huh, Jeannie; Judkins, Timothy; Garg, Sumeet; Miller, Nancy H; Erickson, Mark A

2012-01-01

Serial casting has demonstrated efficacy for idiopathic early-onset scoliosis (EOS). Results of casting in nonidiopathic (syndromic and congenital) EOS patients have not previously been well described. A total of 53 patients underwent serial casting for EOS from 2005 to 2010 at a single institution. Deformity was classified as idiopathic or nonidiopathic. Diagnosis, time in cast, number of casts, use of bracing, complications, and outcomes were recorded. Radiographic measures included Cobb angle and thoracic height (T1-T12). Thoracic height velocity was calculated and compared with established norms. A total of 36 patients, 19 idiopathic and 17 nonidiopathic (14 syndromic, 3 congenital), completed cast treatment and had >6-month follow-up and were therefore included. Of those, 17% (6/36) experienced resolution of their deformity, 53% (19/26) are currently in braces, and 31% (11/36) had undergone surgery. Surgery occurred on average at age 5.6 years and was delayed by an average of 2.1 years from time of first cast. A 19% complication was observed. There was no statistical difference in the rate of resolution of deformity between idiopathic (5/19) and nonidiopathic (1/17) patients (P=0.182), although there exists a trend toward greater curve correction in idiopathic patients. Surgery occurred in fewer patients (2/19) in the idiopathic group compared with the nonidiopathic group (9/17) (P=0.006). Significant improvements in Cobb angle was observed in the idiopathic group (12.2 degrees) during casting (P=0.003). Nonidiopathic patients did not maintain the correction gained during casting at the time of final follow-up. T1-T12 height increased across all study patients regardless of etiology during the period of casting at similar velocity to established norms of 1.4 cm/y for this age group. Serial casting offers modest deformity correction in idiopathic deformities compared with nonidiopathic deformities. Thoracic height growth continued throughout the casting period at normal velocity. Serial casting maintained normal longitudinal thoracic growth in all patients with EOS in this cohort. Although many required surgery, the increased thoracic height may have positive implications on ultimate pulmonary function. Therapeutic level III.

Caste in 21st Century India: Competing Narratives

PubMed Central

Desai, Sonalde; Dubey, Amaresh

2012-01-01

Recent debates regarding inclusion of caste in 2011 Census have raised questions about whether caste still matters in modern India. Ethnographic studies of the mid-20th century identified a variety of dimensions along which caste differentiation occurs. At the same time, whether this differentiation translates into hierarchy remains a contentious issue as does the persistence of caste, given the economic changes of the past two decades. Using data from a nationally representative survey of 41,554 households conducted in 2005, this paper examines the relationship between social background and different dimensions of well-being. The results suggest continued persistence of caste disparities in education, income and social networks. PMID:22736803

Genetic structure of Rajaka caste and affinities with other caste populations of Andhra Pradesh, India.

PubMed

Parvatheesam, C; Babu, B V; Babu, M C

1997-01-01

The present study gives an account of the genetic structure in terms of distribution of a few genetic markers, viz., A1A2B0, Rh(D), G6PD deficiency and haemoglobin among the Rajaka caste population of Andhra Pradesh, India. The genetic relationships of the Rajaka caste with other Andhra caste populations were investigated in terms of genetic distance, i.e., Sq B (mn) of Balakrishnan and Sanghvi. Relatively lesser distance was established between the Rajaka and two Panchama castes. Also, the pattern of genetic distance corroborates the hierarchical order of the Hindu varna system.

Transmutation Fuel Fabrication-Fiscal Year 2016

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fielding, Randall Sidney; Grover, Blair Kenneth

ABSTRACT Nearly all of the metallic fuel that has been irradiated and characterized by the Advanced Fuel Campaign, and its earlier predecessors, has been arc cast. Arc casting is a very flexible method of casting lab scale quantities of materials. Although the method offers flexibility, it is an operator dependent process. Small changes in parameter space or alloy composition may affect how the material is cast. This report provides a historical insight in how the casting process has been modified over the history of the advanced fuels campaign as well as the physical parameters of the fuels cast in fiscalmore » year 2016.« less

A Recipe for Soft Fluidic Elastomer Robots

PubMed Central

Marchese, Andrew D.; Katzschmann, Robert K.

2015-01-01

Abstract This work provides approaches to designing and fabricating soft fluidic elastomer robots. That is, three viable actuator morphologies composed entirely from soft silicone rubber are explored, and these morphologies are differentiated by their internal channel structure, namely, ribbed, cylindrical, and pleated. Additionally, three distinct casting-based fabrication processes are explored: lamination-based casting, retractable-pin-based casting, and lost-wax-based casting. Furthermore, two ways of fabricating a multiple DOF robot are explored: casting the complete robot as a whole and casting single degree of freedom (DOF) segments with subsequent concatenation. We experimentally validate each soft actuator morphology and fabrication process by creating multiple physical soft robot prototypes. PMID:27625913

A Recipe for Soft Fluidic Elastomer Robots.

PubMed

Marchese, Andrew D; Katzschmann, Robert K; Rus, Daniela

2015-03-01

This work provides approaches to designing and fabricating soft fluidic elastomer robots. That is, three viable actuator morphologies composed entirely from soft silicone rubber are explored, and these morphologies are differentiated by their internal channel structure, namely, ribbed, cylindrical, and pleated. Additionally, three distinct casting-based fabrication processes are explored: lamination-based casting, retractable-pin-based casting, and lost-wax-based casting. Furthermore, two ways of fabricating a multiple DOF robot are explored: casting the complete robot as a whole and casting single degree of freedom (DOF) segments with subsequent concatenation. We experimentally validate each soft actuator morphology and fabrication process by creating multiple physical soft robot prototypes.

Microstructure and Corrosion Characterization of Squeeze Cast AM50 Magnesium Alloys

NASA Astrophysics Data System (ADS)

Sachdeva, Deepika; Tiwari, Shashank; Sundarraj, Suresh; Luo, Alan A.

2010-12-01

Squeeze casting of magnesium alloys potentially can be used in lightweight chassis components such as control arms and knuckles. This study documents the microstructural analysis and corrosion behavior of AM50 alloys squeeze cast at different pressures between 40 and 120 MPa and compares them with high-pressure die cast (HPDC) AM50 alloy castings and an AM50 squeeze cast prototype control arm. Although the corrosion rates of the squeeze cast samples are slightly higher than those observed for the HPDC AM50 alloy, the former does produce virtually porosity-free castings that are required for structural applications like control arms and wheels. This outcome is extremely encouraging as it provides an opportunity for additional alloy and process development by squeeze casting that has remained relatively unexplored for magnesium alloys compared with aluminum. Among the microstructural parameters analyzed, it seems that the β-phase interfacial area, indicating a greater degree of β network, leads to a lower corrosion rate. Weight loss was the better method for determining corrosion behavior in these alloys that contain a large fraction of second phase, which can cause perturbations to an overall uniform surface corrosion behavior.

Independent origins of Indian caste and tribal paternal lineages.

PubMed

Cordaux, Richard; Aunger, Robert; Bentley, Gillian; Nasidze, Ivane; Sirajuddin, S M; Stoneking, Mark

2004-02-03

The origins of the nearly one billion people inhabiting the Indian subcontinent and following the customs of the Hindu caste system are controversial: are they largely derived from Indian local populations (i.e. tribal groups) or from recent immigrants to India? Archaeological and linguistic evidence support the latter hypothesis, whereas recent genetic data seem to favor the former hypothesis. Here, we analyze the most extensive dataset of Indian caste and tribal Y chromosomes to date. We find that caste and tribal groups differ significantly in their haplogroup frequency distributions; caste groups are homogeneous for Y chromosome variation and more closely related to each other and to central Asian groups than to Indian tribal or any other Eurasian groups. We conclude that paternal lineages of Indian caste groups are primarily descended from Indo-European speakers who migrated from central Asia approximately 3,500 years ago. Conversely, paternal lineages of tribal groups are predominantly derived from the original Indian gene pool. We also provide evidence for bidirectional male gene flow between caste and tribal groups. In comparison, caste and tribal groups are homogeneous with respect to mitochondrial DNA variation, which may reflect the sociocultural characteristics of the Indian caste society.

Properties of a hybrid plaster-fibreglass cast

PubMed Central

Charles, Mark N.; Yen, David

2000-01-01

Objective To examine the suitability of a plaster-fibreglass hybrid cast for orthopedic applications, comparing them to plaster of Paris (POP) and fibreglass constructs. Method Groups of 10 standardized hybrid, POP and fibreglass casts were studied. An Instron servo-hydraulic system was used to test the casts in 3-point bending and shear. Outcome measures Strength, stiffness, weight, thickness and cost of the 3 types of cast, and shear strength at the interface between the POP and fibreglass in the hybrid casts. Results The hybrid casts were twice as strong as the POP constructs, were stiffer and weighed 14% less but were thicker and cost 2.5 times more. They were almost as strong as and less than half the cost of the fibreglass constructs but were thicker, not as stiff, and weighed 42% more. The shear strength of the POP–fibreglass interface in the hybrid casts was higher than the 3-point bending strength of this construct by a factor of 3. Conclusions Plaster-fibreglass hybrid casts should be considered for orthopedic use on the basis of their strength, stiffness, weight and cost, combined with their acknowledged advantages of good moulding ability and water resistance. PMID:11045095

Short-term after-effect of forearm cast removal in children.

PubMed

Katz, Kalman; Weigl, Daniel; Becker, Tal; Attias, Joseph; Bar-On, Elhanan

2011-05-01

To investigate the sensation in the hand after forearm cast removal in children. The study group included 33 consecutive children who were treated nonoperatively for a forearm fracture at our center over a 1-year period. The children were asked to report any sensation in the ipsilateral hand after cast removal, and the findings were analyzed against background and fracture-related data. The patients ranged in age from 6 to 14 years (median 10.00 years). Seventeen had been immobilized in an above-elbow cast and the remainder in a below-elbow cast. All children treated with an above-elbow cast complained that after cast removal, the hand on that side felt limp, and they had to hold it with the contralateral hand. By contrast, only one child treated with a below-elbow cast reported this sensation (p = 0.0001, Fisher exact test). Orthopedic surgeons and rehabilitation unit staff should be aware of the possibility of a very short-term sensation of drooping and weakness of the hand after removal of an above-elbow cast in children and prepare the child and parents accordingly in order to lessen unnecessary anxiety.

Comparative study on stiffness properties of WOODCAST and conventional casting materials.

PubMed

Pirhonen, Eija; Pärssinen, Antti; Pelto, Mika

2013-08-01

Plaster-of-Paris and synthetic materials (e.g. fibreglass) have been in clinical use as casting materials for decades. An innovative casting material, WOODCAST, brings interesting alternatives to the traditional materials. The aim of this study was to compare the stiffness properties of the WOODCAST material to traditional casting materials. In immobilization by casting, materials with variable stiffness properties are required. Ring stiffness of cylindrical samples correlates well with cast rigidity. For load-bearing structures, the use of the WOODCAST Splint is recommended as equally high stiffness was obtained with the WOODCAST Splint as was with fibreglass. The WOODCAST 2 mm product is optimal for structures where some elasticity is required, and WOODCAST Ribbon can be used in any WOODCAST structure where further reinforcement is needed. The results show that WOODCAST material can be used in replacing traditional casting materials used in extremity immobilization. The mechanical properties of casting material play an important role in safe and effective fracture immobilization. Stiffness properties of the WOODCAST casting material and conventional materials - fibreglass and plaster-of-Paris - were analysed in this study. The WOODCAST Splint appears to compare favorably with traditional materials such as Scotchcast.

Evaluation of marginal gap of Ni-Cr copings made with conventional and accelerated casting techniques.

PubMed

Tannamala, Pavan Kumar; Azhagarasan, Nagarasampatti Sivaprakasam; Shankar, K Chitra

2013-01-01

Conventional casting techniques following the manufacturers' recommendations are time consuming. Accelerated casting techniques have been reported, but their accuracy with base metal alloys has not been adequately studied. We measured the vertical marginal gap of nickel-chromium copings made by conventional and accelerated casting techniques and determined the clinical acceptability of the cast copings in this study. Experimental design, in vitro study, lab settings. Ten copings each were cast by conventional and accelerated casting techniques. All copings were identical, only their mold preparation schedules differed. Microscopic measurements were recorded at ×80 magnification on the perpendicular to the axial wall at four predetermined sites. The marginal gap values were evaluated by paired t test. The mean marginal gap by conventional technique (34.02 μm) is approximately 10 μm lesser than that of accelerated casting technique (44.62 μm). As the P value is less than 0.0001, there is highly significant difference between the two techniques with regard to vertical marginal gap. The accelerated casting technique is time saving and the marginal gap measured was within the clinically acceptable limits and could be an alternative to time-consuming conventional techniques.

Rough case-based reasoning system for continues casting

NASA Astrophysics Data System (ADS)

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.

Detecting novel SNPs and breed-specific haplotypes at calpastatin gene in Iranian fat- and thin-tailed sheep breeds and their effects on protein structure.

PubMed

Aali, Mohsen; Moradi-Shahrbabak, Mohammad; Moradi-Shahrbabak, Hosein; Sadeghi, Mostafa

2014-03-01

Calpastatin has been introduced as a potential candidate gene for growth and meat quality traits. In this study, genetic variability was investigated in the exon 6 and its intron boundaries of ovine CAST gene by PCR-SSCP analysis and DNA sequencing. Also a protein sequence and structural analysis were performed to predict the possible impact of amino acid substitutions on physicochemical properties and structure of the CAST protein. A total of 487 animals belonging to four ancient Iranian sheep breeds with different fat metabolisms, Lori-Bakhtiari and Chall (fat-tailed), Zel-Atabay cross-bred (medium fat-tailed) and Zel (thin-tailed), were analyzed. Eight unique SSCP patterns, representing eight different sequences or haplotypes, CAST-1, CAST-2 and CAST-6 to CAST-11, were identified. Haplotypes CAST-1 and CAST-2 were most common with frequency of 0.365 and 0.295. The novel haplotype CAST-8 had considerable frequency in Iranian sheep breeds (0.129). All the consensus sequences showed 98-99%, 94-98%, 92-93% and 82-83% similarity to the published ovine, caprine, bovine and porcine CAST locus sequences, respectively. Sequence analysis revealed four SNPs in intron 5 (C24T, G62A, G65T and T69-) and three SNPs in exon 6 (c.197A>T, c.282G>T and c.296C>G). All three SNPs in exon 6 were missense mutations which would result in p.Gln 66 Leu, p.Glu 94 Asp and p.Pro 99 Arg substitutions, respectively, in CAST protein. All three amino acid substitutions affected the physicochemical properties of ovine CAST protein including hydrophobicity, amphiphilicity and net charge and subsequently might influence its structure and effect on the activity of Ca2+ channels; hence, they might regulate calpain activity and afterwards meat tenderness and growth rate. The Lori-Bakhtiari population showed the highest heterozygosity in the ovine CAST locus (0.802). Frequency difference of haplotypes CAST-10 and CAST-8 between Lori-Bakhtiari (fat-tailed) and Zel (thin-tailed) breeds was highly significant (P<0.001), indicating that these two haplotypes might be breed-specific haplotypes that distinguish between fat-tailed and thin-tailed sheep breeds. Copyright © 2013 Elsevier B.V. All rights reserved.

Quengel Casting for the Management of Pediatric Knee Flexion Contractures: A 26-Year Single Institution Experience.

PubMed

Wiley, Marcel R; Riccio, Anthony I; Felton, Kevin; Rodgers, Jennifer A; Wimberly, Robert L; Johnston, Charles E

Quengel casting was introduced in 1922 for nonsurgical treatment of knee flexion contractures (KFC) associated with hemophilic arthropathy. It consists of an extension-desubluxation hinge fixed to a cast allowing for gradual correction of a flexion deformity while preventing posterior tibial subluxation. The purpose of this study is to report 1 center's experience with this technique for the treatment of pediatric KFC. A retrospective review was conducted over a 26-year period. All patients with KFC treated with Quengel casting were included. Demographic data, associated medical conditions, adjunctive soft tissue releases, complications, and the need for late surgical intervention were recorded. Tibiofemoral angle measurements in maximal extension were recorded at initiation and termination of casting, 1-year follow-up, and final follow-up. Success was defined as no symptomatic recurrence of KFC or need for subsequent surgery. Eighteen patients (26 knees) were treated for KFC with Quengel casting. Average age at initiation of casting was 8.1 years with average follow-up of 59.9 months. Fifteen knees (58%) underwent soft tissue releases before casting. An average of 1.5 casts per knee were applied over an average of 23.9 days. Average KFC before casting was 50.6 degrees (range, 15 to 100 degrees) which improved to 5.96 degrees (0 to 40 degrees) at cast removal (P<0.00001). Sixteen patients (22 knees) had 1-year follow-up or failed casting before 1 year. Of these, 11 knees (50%) had a successful outcome. Residual KFC of those treated successfully was 6.8 degrees (range, 0 to 30 degrees) at 1 year and 8.2 degrees (range, 0 to 30 degrees) at final follow-up, averaging 71.4 months (P=0.81). Of the 11 knees deemed failures, all had recurrence of deformity within an average of 1 year from cast removal. Surgical release before Quengel casting did not improve the chances for success (P=0.09). Quengel casting can improve pediatric KFC an average of 44.2 degrees with minimal complications. Although 50% of treated patients will demonstrate significant recurrence or need later surgery, the majority of those treated successfully have durable results at intermediate term follow-up. Level IV-therapeutic study.

75 FR 49945 - Iron Construction Castings From Brazil, Canada, and China

Federal Register 2010, 2011, 2012, 2013, 2014

2010-08-16

... Review)] Iron Construction Castings From Brazil, Canada, and China AGENCY: United States International... and antidumping duty orders on iron construction castings from Brazil, Canada, and China. SUMMARY: The... duty and or antidumping duty orders on iron construction castings from Brazil, Canada, and China would...

76 FR 63936 - Agency Information Collection Activities: Proposed Collection; Comment Request; PrepCAST

Federal Register 2010, 2011, 2012, 2013, 2014

2011-10-14

...CAST AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: The Federal Emergency...CAST) (formerly known as the National Incident Management System Compliance Assistance Support Tool (NIMSCAST)). PrepCAST is a self-assessment tool for State, territorial, Tribal, and local governments to...

40 CFR 464.25 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) EFFLUENT GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Copper Casting... existing sources. (a) Casting Quench Operations. PSES Pollutant or pollutant property Maximum for any 1 day... monitoring) 1.2 0.399 (b) Direct Chill Casting Operations. PSES Pollutant or pollutant property Maximum for...

Application of TRIZ Theory in Patternless Casting Manufacturing Technique

NASA Astrophysics Data System (ADS)

Yang, Weidong; Gan, Dequan; Jiang, Ping; Tian, Yumei

The ultimate goal of Patternless Casting Manufacturing (referred to as PCM) is how to obtain the casts by casting the sand mold directly. In the previous PCM, the resin content of sand mold is much higher than that required by traditional resin sand, so the casts obtained are difficult to be sound and qualified products, which limits the application of this technique greatly. In this paper, the TRIZ algorithm is introduced to the innovation process in PCM systematically.

Report on results of current and future metal casting

DOE Office of Scientific and Technical Information (OSTI.GOV)

Unal, Cetin; Carlson, Neil N.

2015-09-28

New modeling capabilities needed to simulate the casting of metallic fuels are added to Truchas code. In this report we summarize improvements we made in FY2015 in three areas; (1) Analysis of new casting experiments conducted with BCS and EFL designs, (2) the simulation of INL’s U-Zr casting experiments with Flow3D computer program, (3) the implementation of surface tension model into Truchas for unstructured mesh required to run U-Zr casting.

The ToxCast Chemical Landscape - Paving the Road to 21st ...

EPA Pesticide Factsheets

The ToxCast high-throughput screening (HTS) program within the U.S. Environmental Protection Agency (EPA) was launched in 2007. Phase I of the program screened 310 chemicals, mostly pesticides, across hundreds of ToxCast assay endpoints. In Phase II, the ToxCast library was expanded to 1878 chemicals, culminating in public release of screening data at the end of 2013. Concurrently, a larger EPA library of 3726 chemicals (including the Phase II chemicals) was undergoing screening in the cross-federal agency Tox21 HTS project. Four years later, Phase III of EPA’s ToxCast program is actively screening a diverse library consisting of more than 3800 chemicals, 96% of which are also undergoing Tox21 screening. The majority of ToxCast studies, to date, have focused on using HTS results to build biologically based models for predicting in vivo toxicity endpoints. The focus of the present article, in contrast, is on the EPA chemical library underpinning these efforts. A history of the phased construction of EPA’s ToxCast library is presented, considering factors influencing chemical selection as well as the various quality measures implemented. Next, Chemical Abstracts Service Registry Numbers (CASRN), which were used to compile initial chemical nominations for ToxCast testing, are used to assess overlaps of the current ToxCast library with important toxicity, regulatory, and exposure inventories. Lastly, ToxCast chemicals are described in terms of generaliz

Comparative Evaluation of Conventional and Accelerated Castings on Marginal Fit and Surface Roughness.

PubMed

Jadhav, Vivek Dattatray; Motwani, Bhagwan K; Shinde, Jitendra; Adhapure, Prasad

2017-01-01

The aim of this study was to evaluate the marginal fit and surface roughness of complete cast crowns made by a conventional and an accelerated casting technique. This study was divided into three parts. In Part I, the marginal fit of full metal crowns made by both casting techniques in the vertical direction was checked, in Part II, the fit of sectional metal crowns in the horizontal direction made by both casting techniques was checked, and in Part III, the surface roughness of disc-shaped metal plate specimens made by both casting techniques was checked. A conventional technique was compared with an accelerated technique. In Part I of the study, the marginal fit of the full metal crowns as well as in Part II, the horizontal fit of sectional metal crowns made by both casting techniques was determined, and in Part III, the surface roughness of castings made with the same techniques was compared. The results of the t -test and independent sample test do not indicate statistically significant differences in the marginal discrepancy detected between the two casting techniques. For the marginal discrepancy and surface roughness, crowns fabricated with the accelerated technique were significantly different from those fabricated with the conventional technique. Accelerated casting technique showed quite satisfactory results, but the conventional technique was superior in terms of marginal fit and surface roughness.

The effects of weld-repair and hot isostatic pressing on the fracture properties of Ti-5Al-2.5Sn ELI castings

NASA Technical Reports Server (NTRS)

Misra, M. S.; Lemeshewsky, S.; Bolstad, D.

1982-01-01

The Ti-5Al-2.5Sn extremely low interstitial alloy employed in the large castings which form the critical attachment fittings of the Space Shuttle External Tank was selected because of its high fracture resistance at cryogenic temperatures. Casting was selected over alternative fabrication methods because of its lower cost and adaptability to design changes, although it was found necessary to weld-repair surface and subsurface casting defects in order to reduce the scrap rate and maintain the inherent cost advantage of the castings. Hot Isostatic Pressing was experimentally found to heal the surface and internal defects of the castings, but did not improve tensile or fracture properties and was therefore rejected as a production technique. Production castings are instead weld-repaired, without any mechanical property degradation.

Method and mold for casting thin metal objects

DOEpatents

Pehrson, Brandon P; Moore, Alan F

2014-04-29

Provided herein are various embodiments of systems for casting thin metal plates and sheets. Typical embodiments include layers of mold cavities that are oriented vertically for casting the metal plates. In some embodiments, the mold cavities include a beveled edge such that the plates that are cast have a beveled edge. In some embodiments, the mold cavities are filled with a molten metal through an open horizontal edge of the cavity. In some embodiments, the mold cavities are filled through one or more vertical feed orifices. Further disclosed are methods for forming a thin cast metal plate or sheet where the thickness of the cast part is in a range from 0.005 inches to 0.2 inches, and the surface area of the cast part is in a range from 16 square inches to 144 square inches.

Method for casting thin metal objects

DOEpatents

Pehrson, Brandon P; Moore, Alan F

2015-04-14

Provided herein are various embodiments of systems for casting thin metal plates and sheets. Typical embodiments include layers of mold cavities that are oriented vertically for casting the metal plates. In some embodiments, the mold cavities include a beveled edge such that the plates that are cast have a beveled edge. In some embodiments, the mold cavities are filled with a molten metal through an open horizontal edge of the cavity. In some embodiments, the mold cavities are filled through one or more vertical feed orifices. Further disclosed are methods for forming a thin cast metal plate or sheet where the thickness of the cast part is in a range from 0.005 inches to 0.2 inches, and the surface area of the cast part is in a range from 16 square inches to 144 square inches.

Cause and Prevention of Explosions Involving DC Casting of Aluminum Sheet Ingot

NASA Astrophysics Data System (ADS)

Richter, Ray T.; Ekenes, J. Martin

The casting of aluminum alloy sheet ingot and T-bar presents the potential for some of the most volatile situations that can occur in DC (direct chill) and EMC (Electromagnetic) casting processes. Aluminum Association explosion incident data from over 300 explosions spanning a twenty-year period were reviewed and analyzed looking for common factors and repetitive reasons for explosions. Analysis of explosions occurring during the three stages of sheet ingot casting, `start of cast', `steady state' and `end of cast', were examined and prioritized. Case studies illustrate the need for understanding both technical and non-technical factors contributing to explosions involving molten metal. This paper identifies the major causes of explosions involving DC casting of aluminum alloy sheet ingot and makes recommendations for how to prevent the recurrence of such events and minimize the risk of injury.

Sealed vacuum canister and method for pick-up and containment of material

DOEpatents

Stoutenburgh, Roger R.

1996-01-01

A vacuum canister including a housing with a sealed vacuum chamber having a predetermined vacuum pressure therein and a valve having a first port for fluid communication with the vacuum chamber and a second port for receiving at least one of a fluid and a particulate material. The valve is operable between a first position to seal the vacuum chamber and retain the predetermined vacuum within the vacuum chamber, and a second position to access the vacuum chamber to permit vacuum fluid flow through the valve from the second port into the vacuum chamber. In operation of the vacuum canister to pick up material with the valve in the second position, when the second port is located adjacent at least one of a fluid and a particulate material, is effective to displace through the valve at least one of a fluid and a particulate material into the housing. The vacuum canister is desirably suitable for picking up and containing hazardous material such as radioactive material, in which the vacuum canister includes a protective layer of lead having a predetermined thickness that is effective to shield radiation emitted from the radioactive material contained within the housing. Advantageously, the vacuum canister includes a vacuum means for establishing a predetermined vacuum pressure within the vacuum chamber.

Sealed vacuum canister and method for pick-up and containment of material

DOEpatents

Stoutenburgh, R.R.

1996-02-13

A vacuum canister is described including a housing with a sealed vacuum chamber having a predetermined vacuum pressure therein and a valve having a first port for fluid communication with the vacuum chamber and a second port for receiving at least one of a fluid and a particulate material. The valve is operable between a first position to seal the vacuum chamber and retain the predetermined vacuum within the vacuum chamber, and a second position to access the vacuum chamber to permit vacuum fluid flow through the valve from the second port into the vacuum chamber. The vacuum canister, in the operation to pick up material with the valve in the second position, when the second port is located adjacent at least one of a fluid and a particulate material, is effective to displace through the valve at least one of a fluid and a particulate material into the housing. The vacuum canister is desirably suitable for picking up and containing hazardous material such as radioactive material, in which the vacuum canister includes a protective layer of lead having a predetermined thickness that is effective to shield radiation emitted from the radioactive material contained within the housing. Advantageously, the vacuum canister includes a vacuum means for establishing a predetermined vacuum pressure within the vacuum chamber. 6 figs.

Optimization of Squeeze Casting for Aluminum Alloy Parts

DOE Office of Scientific and Technical Information (OSTI.GOV)

David Schwam; John F. Wallace; Qingming Chang

2002-07-30

This study was initiated with the installation of a new production size UBE 350 Ton VSC Squeeze Casting system in the Metal Casting Laboratory at Case Western University. A Lindberg 75k W electrical melting furnace was installed alongside. The challenge of installation and operation of such industrial-size equipment in an academic environment was met successfully. Subsequently, a Sterling oil die heater and a Visi-Track shot monitoring system were added. A significant number of inserts were designed and fabricated over the span of the project, primarily for squeeze casting different configurations of test bars and plates. A spiral ''ribbon insert'' formore » evaluation of molten metal fluidity was also fabricated. These inserts were used to generate a broad range of processing conditions and determine their effect on the quality of the squeeze cast parts. This investigation has studied the influence of the various casting variables on the quality of indirect squeeze castings primarily of aluminum alloys. The variables studied include gating design, fill time and fill patter, metal pressure and die temperature variations. The quality of the die casting was assessed by an analysis of both their surface condition and internal soundness. The primary metal tested was an aluminum 356 alloy. In addition to determining the effect of these casting variables on casting quality as measured by a flat plate die of various thickness, a number of test bar inserts with different gating designs have been inserted in the squeeze casting machine. The mechanical properties of these test bars produced under different squeeze casting conditions were measured and reported. The investigation of the resulting properties also included an analysis of the microstructure of the squeeze castings and the effect of the various structural constituents on the resulting properties. The main conclusions from this investigation are as follows: The ingate size and shape are very important since it must remain open until the casting is solidified and pressure is maintained on the solidifying casting. Fanned gates, particularly on the smaller section castings avoid jetting effects at the ingate end. The fan type ingate helps accomplish a rapid fill without high velocities. The molten metal has to fill the cavity before localized solidification occurs. This is best accomplished with a larger ingate to attain rapid filling without excessive velocity or jetting that occurs at high metal velocities. Straight gates are prone to case jetting of the metal stream even a low velocities. Fanned gates allow use of higher fill velocity without excessive jetting. A higher metal pressure provides a more complete fill of the die including improved compensation for solidification shrinkage. With the proper filling pattern, ingates, overflows and die temperature for a given die, very good tensile properties can be attained in squeeze casting. In general, the smaller squeeze castings require higher die temperatures. Computer models using the UES Procast and MagmaSoft finite element software can, after suitable adjustments, predict the flow pattern in the die cavity.« less

Data Package for Secondary Waste Form Down-Selection—Cast Stone

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 andmore » 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.« less

21 CFR 888.5940 - Cast component.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Cast component. 888.5940 Section 888.5940 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.5940 Cast component. (a) Identification. A cast component is a...

21 CFR 888.5940 - Cast component.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Cast component. 888.5940 Section 888.5940 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.5940 Cast component. (a) Identification. A cast component is a...

21 CFR 888.5940 - Cast component.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Cast component. 888.5940 Section 888.5940 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.5940 Cast component. (a) Identification. A cast component is a...

Updates on EPA’s High-Throughput Exposure Forecast (ExpoCast) Research Project (CPCP)

EPA Science Inventory

Recent research advances by the ORD ExpoCast project (CSS Rapid Exposure and Dosimetry) are presented to the computational toxicology community in the context of prioritizing chemicals on a risk-basis using joint ExpoCast and ToxCast predictions. Recent publications by Wambaugh e...

Casting copper to tungsten for high-power arc lamp cathodes

NASA Technical Reports Server (NTRS)

Will, H. A.

1974-01-01

Voids forming at interface when copper is cast onto tungsten can be eliminated by adding wetting agent during casting process. Small amount of copper and nickel are cast onto thoriated tungsten insert, insert is recast with more copper to form electrode. Good thermal conductance results in long-lived cathode.

75 FR 67395 - Iron Construction Castings From Brazil, Canada, and China; Determinations

Federal Register 2010, 2011, 2012, 2013, 2014

2010-11-02

... Review)] Iron Construction Castings From Brazil, Canada, and China; Determinations On the basis of the...), that revocation of the countervailing duty order on heavy iron construction castings from Brazil, the... iron construction castings (both heavy and light) from Brazil and China would be likely to lead to...

40 CFR 464.40 - Applicability; description of the zinc casting subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 30 2011-07-01 2011-07-01 false Applicability; description of the zinc... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Zinc Casting Subcategory § 464.40 Applicability; description of the zinc casting subcategory. The provisions of this...

40 CFR 464.40 - Applicability; description of the zinc casting subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Applicability; description of the zinc... (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Zinc Casting Subcategory § 464.40 Applicability; description of the zinc casting subcategory. The provisions of this...

76 FR 27668 - Algonac Cast Products, Inc., Algonac, MI; Notice of Revised Determination on Reconsideration

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-12

... DEPARTMENT OF LABOR Employment and Training Administration [TA-W-74,549] Algonac Cast Products... workers and former workers of Algonac Cast Products, Inc., Algonac, Michigan (subject firm) to apply for... Algonac Cast Products, Inc., Algonac, Michigan. Conclusion After careful review of the additional facts...

40 CFR 464.16 - Pretreatment standards for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Aluminum Casting Subcategory § 464... CFR part 403 and achieve the following pretreatment standards for new sources. (a) Casting Cleaning...) 0.114 0.0431 (b) Casting Quench Operations. PSNS Pollutant or pollutant property Maximum for any 1...

40 CFR 464.26 - Pretreatment standards for new sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

... GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Copper Casting Subcategory § 464.26... and achieve the following pretreatment standards for new sources. (a) Casting Quench Operations. PSNS... 0.0335 0.0109 Oil and grease (for alternate monitoring) 1.2 0.399 (b) Direct Chill Casting...

21 CFR 888.5980 - Manual cast application and removal instrument.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Manual cast application and removal instrument... SERVICES (CONTINUED) MEDICAL DEVICES ORTHOPEDIC DEVICES Surgical Devices § 888.5980 Manual cast application and removal instrument. (a) Identification. A manual cast application and removal instrument is a...

The Ins and Outs of Relief Casting.

ERIC Educational Resources Information Center

Greene, Yvonne

2000-01-01

Describes a unit on clay casting that introduces students to relief sculpture. The unit takes three 45 to 50 minute class periods three weeks apart. Discusses each class session in detail: (1) creating the casting; (2) turning out and rinsing the casting; and (3) enriching the surface with color. (CMK)

40 CFR 464.15 - Pretreatment standards for existing sources.

Code of Federal Regulations, 2010 CFR

2010-07-01

...) EFFLUENT GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Aluminum Casting... existing sources. (a) Casting Cleaning Operations. PSES Pollutant or pollutant property Maximum for any 1....0771 0.0421 Lead (T) 0.0791 0.039 Zinc (T) 0.114 0.0431 (b) Casting Quench Operation. PSES Pollutant or...

49 CFR 192.755 - Protecting cast-iron pipelines.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 49 Transportation 3 2010-10-01 2010-10-01 false Protecting cast-iron pipelines. 192.755 Section... NATURAL AND OTHER GAS BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Maintenance § 192.755 Protecting cast-iron pipelines. When an operator has knowledge that the support for a segment of a buried cast-iron...

77 FR 8272 - Agency Information Collection Activities: Submission for OMB Review; Comment Request, PrepCAST.

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-14

..., PrepCAST. AGENCY: Federal Emergency Management Agency, DHS. ACTION: Notice. SUMMARY: The Federal... . SUPPLEMENTARY INFORMATION: Collection of Information Title: PrepCAST. Type of information collection: Revision.... Abstract: PrepCAST is a collection instrument that will collect preparedness information at the State...

40 CFR 721.10667 - Slimes and sludges, aluminum and iron casting, wastewater treatment, solid waste.

Code of Federal Regulations, 2014 CFR

2014-07-01

... casting, wastewater treatment, solid waste. 721.10667 Section 721.10667 Protection of Environment... iron casting, wastewater treatment, solid waste. (a) Chemical substance and significant new uses... and iron casting, wastewater treatment, solid waste (PMN P-12-560; CAS No. 1391739-82-4; chemical...

40 CFR 721.10667 - Slimes and sludges, aluminum and iron casting, wastewater treatment, solid waste.

Code of Federal Regulations, 2013 CFR

2013-07-01

... casting, wastewater treatment, solid waste. 721.10667 Section 721.10667 Protection of Environment... iron casting, wastewater treatment, solid waste. (a) Chemical substance and significant new uses... and iron casting, wastewater treatment, solid waste (PMN P-12-560; CAS No. 1391739-82-4; chemical...

The ToxCast Chemical Landscape - Paving the Road to 21st Century Toxicology

EPA Science Inventory

The ToxCast high-throughput screening (HTS) program within the U.S. Environmental Protection Agency (EPA) was launched in 2007. Phase I of the program screened 310 chemicals, mostly pesticides, across hundreds of ToxCast assay endpoints. In Phase II, the ToxCast library was exp...

When Your Child Needs a Cast

MedlinePlus

... a waterproof plastic cast protector instead of plastic bags. You can buy this at a drugstore. Keep the cast completely out of the water by propping it up on the side of the tub. If the cast or liner gets splashed, gently blow air into it from a hair dryer on the ...

21 CFR 888.5940 - Cast component.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Cast component. 888.5940 Section 888.5940 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... the cast heel, toe cap, cast support, and walking iron. (b) Classification. Class I (general controls...

21 CFR 888.5940 - Cast component.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cast component. 888.5940 Section 888.5940 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES... the cast heel, toe cap, cast support, and walking iron. (b) Classification. Class I (general controls...

Netcast™ Shape Casting Technology: A Technological Breakthrough that Enhances the Cost Effectiveness of Aluminum Forgings

NASA Astrophysics Data System (ADS)

Anderson, Mark; Bruski, Richard; Groszkiewicz, Daniel; Wagstaff, Bob

A new Direct Chill (DC) casting process is introduced to semi-continuous casting where near net shaped ingots are solidified. This process is currently being used at Alcan Engineered Cast Products (ECP) facility in Jonquiere, Canada, sectioned, then forged at Alcoa Automotive, Kentucky Casting Center (KCC). Finished forgings are machined and assembled into the Ford D/EW98 platform as suspension components. A brief description of the process and the implications on the forging process are presented.

Rapid Cycle Casting of Steel

DTIC Science & Technology

1981-07-01

C’, and at temperature T, are Infiltrated by !L amougt of liquid of composition C’., such that ,C, 4 f+.C’L - X. V. 7 average carbon content of the...maximum liquid penetration was 100 mm at an infiltration pressure of 755 kPa. The average casting composition was 0.94 w/o carbon . The segregation at...content* at four casting locations. 2. Results The casting composition ( carbon content) as a function of casting location is given in Table D-IV. The

The role of water in slip casting

NASA Technical Reports Server (NTRS)

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.

Research of Mechanical Property Gradient Distribution of Al-Cu Alloy in Centrifugal Casting

NASA Astrophysics Data System (ADS)

Sun, Zhi; Sui, Yanwei; Liu, Aihui; Li, Bangsheng; Guo, Jingjie

Al-Cu alloy castings are obtained using centrifugal casting. The regularity of mechanical property gradient distribution of Al-Cu alloy castings with the same centrifugal radius at different positions is investigated. The result shows that the tensile strength, yield strength, elongation and microscope hardness exhibit the following gradient distribution characteristic — high on both sides and low on the center. The trend of mechanical property gradient distribution of Al-Cu alloy increases with the increase in the rotation speed. Moreover, the mechanical properties of casting centerline two sides have asymmetry. The reason is that the grain size of casting centerline two sides and Al2Cu phase and Cu content change correspondingly.

ICAM Manufacturing Cost/Design Guide. Volume 3. Airframes. User’s Manual.

DTIC Science & Technology

1983-01-01

COST-DRIVER EFFECT 17 -413H Investment Cast 17 - 4PH Investment Cast 2 2 - U) *oo 0±0.01 ±0.02 ±0.03 0±0.01 ±0.02 ±0.03 356iA356 Aluminum 356/A356...B +20% CAST B +50% 17 - 4PH CRES DORC BASE INVESTMENT D OR C WITH 10% B +20% CAST D OR C WITH 50% B +30% B +60% NOTE: X-Ray Grade A Is an Impractical...per QQ-A-601 (sand castings) - 357 per MIL-A-21180 (sand castings) a Steel - 17 - 4PH CRES per AMS-5342, 5343, and 5344 or * company equivalent

Effect of carbon content on friction and wear of cast irons

NASA Technical Reports Server (NTRS)

Buckley, D. H.

1977-01-01

Friction and wear experiments were conducted with cast irons and wrought steels containing various amounts of carbon in the alloy structure in contact with 52100 steel. Gray cast irons were found to exhibit lower friction and wear characteristics than white cast irons. Further, gray cast iron wear was more sensitive to carbon content than was white. Wear with gray cast iron was linearly related to load, and friction was found to be sensitive to relative humidity and carbon content. The form, in which the carbon is present in the alloy, is more important, as the carbon content and no strong relationship seems to exist between hardness of these ferrous alloys and wear.

An objective assessment of safety to drive in an upper limb cast.

PubMed

Stevenson, H L; Peterson, N; Talbot, C; Dalal, S; Watts, A C; Trail, I A

2013-03-01

Patients managed with upper limb cast immobilization often seek advice about driving. There is very little published data to assist in decision making, and advice given varies between healthcare professionals. There are no specific guidelines available from the UK Drivers and Vehicles Licensing Agency, police, or insurance companies. Evidence-based guidelines would enable clinicians to standardize the advice given to patients. Six individuals (three male, three female; mean age 36 years, range 27-43 years) were assessed by a mobility occupational therapist and driving standards agency examiner while completing a formal driving test in six different types of upper limb casts (above-elbow, below-elbow neutral, and below-elbow cast incorporating the thumb [Bennett's cast]) on both left and right sides. Of the 36 tests, participants passed 31 tests, suggesting that most people were able to safely drive with upper limb cast immobilization. However, driving in a left above-elbow cast was considered unsafe.

A Winning Cast

NASA Technical Reports Server (NTRS)

2001-01-01

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

In Situ Casting and Imaging of the Rat Airway Tree for Accurate 3D Reconstruction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jacob, Rick E.; Colby, Sean M.; Kabilan, Senthil

The use of anatomically accurate, animal-specific airway geometries is important for understanding and modeling the physiology of the respiratory system. One approach for acquiring detailed airway architecture is to create a bronchial cast of the conducting airways. However, typical casting procedures either do not faithfully preserve the in vivo branching angles, or produce rigid casts that when removed for imaging are fragile and thus easily damaged. We address these problems by creating an in situ bronchial cast of the conducting airways in rats that can be subsequently imaged in situ using 3D micro-CT imaging. We also demonstrate that deformations inmore » airway branch angles resulting from the casting procedure are small, and that these angle deformations can be reversed through an interactive adjustment of the segmented cast geometry. Animal work was approved by the Institutional Animal Care and Use Committee of Pacific Northwest National Laboratory.« less

Casting And Solidification Technology (CAST): Directional solidification phenomena in a metal model at reduced gravity

NASA Technical Reports Server (NTRS)

Mccay, M. H.

1988-01-01

The Casting and Solidification Technology (CAST) experiment will study the phenomena that occur during directional solidification of an alloy, e.g., constitutional supercooling, freckling, and dendrite coarsening. The reduced gravity environment of space will permit the individual phenomena to be examined with minimum complication from buoyancy driven flows.

49 CFR 192.489 - Remedial measures: Cast iron and ductile iron pipelines.

Code of Federal Regulations, 2011 CFR

2011-10-01

... for Corrosion Control § 192.489 Remedial measures: Cast iron and ductile iron pipelines. (a) General graphitization. Each segment of cast iron or ductile iron pipe on which general graphitization is found to a... 49 Transportation 3 2011-10-01 2011-10-01 false Remedial measures: Cast iron and ductile iron...

49 CFR 192.489 - Remedial measures: Cast iron and ductile iron pipelines.

Code of Federal Regulations, 2010 CFR

2010-10-01

... for Corrosion Control § 192.489 Remedial measures: Cast iron and ductile iron pipelines. (a) General graphitization. Each segment of cast iron or ductile iron pipe on which general graphitization is found to a... 49 Transportation 3 2010-10-01 2010-10-01 false Remedial measures: Cast iron and ductile iron...

40 CFR 464.40 - Applicability; description of the zinc casting subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 31 2012-07-01 2012-07-01 false Applicability; description of the zinc casting subcategory. 464.40 Section 464.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) METAL MOLDING AND CASTING POINT SOURCE CATEGORY Zinc Casting Subcategory § 464.40...

40 CFR 464.40 - Applicability; description of the zinc casting subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 31 2013-07-01 2013-07-01 false Applicability; description of the zinc casting subcategory. 464.40 Section 464.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) METAL MOLDING AND CASTING POINT SOURCE CATEGORY Zinc Casting Subcategory § 464.40...

40 CFR 464.40 - Applicability; description of the zinc casting subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 30 2014-07-01 2014-07-01 false Applicability; description of the zinc casting subcategory. 464.40 Section 464.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) METAL MOLDING AND CASTING POINT SOURCE CATEGORY Zinc Casting Subcategory § 464.40...

75 FR 10216 - Malleable Cast Iron Pipe Fittings from the People's Republic of China: Notice of Rescission of...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-05

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-881] Malleable Cast Iron Pipe... antidumping duty order on malleable cast iron pipe fittings from the People's Republic of China (``PRC''). See... malleable cast iron pipe fittings from the PRC. See Initiation of Antidumping and Countervailing Duty...

46 CFR 153.239 - Use of cast iron.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Use of cast iron. 153.239 Section 153.239 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SHIPS CARRYING BULK... Systems § 153.239 Use of cast iron. (a) Cast iron used in a cargo containment system must meet the...

78 FR 74163 - Johnstown Specialty Castings Inc., a Subsidiary of WHEMCO, Including On-Site Leased Workers From...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-12-10

... Castings Inc., a Subsidiary of WHEMCO, Including On-Site Leased Workers From Berkebile Excavating Company... Assistance on June 25, 2013, applicable to workers of Johnstown Specialty Castings, Inc., a subsidiary of... Castings, Inc., a subsidiary of WHEMCO. The Department has determined that these workers were sufficiently...

78 FR 68474 - Non-Malleable Cast Iron Pipe Fittings From China; Scheduling of an Expedited Five-Year Review...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-11-14

... INTERNATIONAL TRADE COMMISSION [Investigation No. 731-TA-990 (Second Review)] Non-Malleable Cast... Duty Order on Non-Malleable Cast Iron Pipe Fittings From China AGENCY: United States International... determine whether revocation of the antidumping duty order on non-malleable cast iron pipe fittings from...

The use of porcine corrosion casts for teaching human anatomy.

PubMed

Eberlova, Lada; Liska, Vaclav; Mirka, Hynek; Tonar, Zbynek; Haviar, Stanislav; Svoboda, Milos; Benes, Jan; Palek, Richard; Emingr, Michal; Rosendorf, Jachym; Mik, Patrik; Leupen, Sarah; Lametschwandtner, Alois

2017-09-01

In teaching and learning human anatomy, anatomical autopsy and prosected specimens have always been indispensable. However, alternative methods must often be used to demonstrate particularly delicate structures. Corrosion casting of porcine organs with Biodur E20 ® Plus is valuable for teaching and learning both gross anatomy and, uniquely, the micromorphology of cardiovascular, respiratory, digestive, and urogenital systems. Assessments of casts with a stereomicroscope and/or scanning electron microscope as well as highlighting cast structures using color coding help students to better understand how the structures that they have observed as two-dimensional images actually exist in three dimensions, and students found using the casts to be highly effective in their learning. Reconstructions of cast hollow structures from (micro-)computed tomography scans and videos facilitate detailed analyses of branching patterns and spatial arrangements in cast structures, aid in the understanding of clinically relevant structures and provide innovative visual aids. The casting protocol and teaching manual we offer can be adjusted to different technical capabilities and might also be found useful for veterinary or other biological science classes. Copyright © 2017 Elsevier GmbH. All rights reserved.

Prediction model of austenite growth and the role of MnS inclusions in non-quenched and tempered steel

NASA Astrophysics Data System (ADS)

Jiang, Bo; Wu, Meng; Sun, He; Wang, Zhilin; Zhao, Zhigang; Liu, Yazheng

2018-01-01

The austenite growth behavior of non-quenched and tempered steels (casted by continuous casting and molding casting processes) was studied. The austenite grain size of steel B casted by continuous casting process is smaller than that of steel A casted by molding casting process at the same heating parameters. The abnormal austenite growth temperature of the steels A and B are 950 °C and 1000 °C, respectively. Based on the results, the models for the austenite grain growth below and above the abnormal austenite growth temperature of the investigated steels were established. The dispersedly distributed fine particles MnS in steel B is the key factor refining the austenite grain by pinning the migration of austenite grain boundary. The elongated inclusions MnS are ineffective in preventing the austenite grain growth at high heating temperature. For the non-quenched and tempered steel, the continuous casting process should be adopted and the inclusion MnS should be elliptical, smaller in size and distributed uniformly in order to refine the final microstructure and also improve the mechanical properties.

The Effect of Sr Modifier Additions on Double Oxide Film Defects in 2L99 Alloy Castings

NASA Astrophysics Data System (ADS)

Chen, Qi; Griffiths, W. D.

2017-11-01

In this paper, Sr modifier (300 ppm) was added to 2L99 alloy sand castings to investigate its effect on bifilm defects in the castings. Two different sand molds were used in this study, with good and bad running system designs, to introduce different amounts of bifilm defects into the castings. The mechanical properties of the modified 2L99 castings were compared to the properties of unmodified castings and showed that with high bifilm defect contents (H) the Sr addition reduced the Weibull modulus of the UTS by 67 pct and the Position Parameter by 5 pct, and introduced a bimodal distribution into the Weibull plot of the pct Elongation. However, for castings with low bifilm defect content (L), the Weibull moduli of both the UTS and pct Elongation were significantly improved (by 78 and 73 pct, respectively) with the addition of Sr. The Position Parameter of the pct Elongation was improved by 135 pct. The results suggested that a desirable modification effect can only be achieved while the bifilm defect content in a casting was low.

Glovebox Advanced Casting System Casting Optimization

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fielding, Randall Sidney

2016-03-01

Casting optimization in the GACS included three broad areas; casting of U-10Zr pins, incorporation of an integral FCCI barrier, and development of a permanent crucible coating. U-10Zr casting was improved over last year’s results by modifying the crucible design to minimize contact with the colder mold. Through these modifications casting of a three pin batch was successful. Incorporation of an integral FCCI barrier also was optimized through furnace chamber pressure changes during the casting cycle to reduce gas pressures in the mold cavities which led to three full length pins being cast which incorporated FCCI barriers of three different thicknesses.more » Permanent crucible coatings were tested against a base case; 1500°C for 10 minutes in a U-20Pu-10Zr molten alloy. None of the candidate coating materials showed evidence of failure upon initial visual examination. In all areas of work a large amount of characterization will be needed to fully determine the effects of the optimization activities. The characterization activities and future work will occur next year.« less

Characterization and expression of the calpastatin gene in Cyprinus carpio.

PubMed

Chen, W X; Ma, Y

2015-07-03

Calpastatin, an important protein used to regulate meat quality traits in animals, is encoded by the CAST gene. The aim of the present study was to clone the cDNA sequence of the CAST gene and detect the expression of CAST in the tissues of Cyprinus carpio. The cDNA of the C. carpio CAST gene, amplified using rapid amplification of cDNA ends PCR, is 2834 bp in length (accession No. JX275386), contains a 2634-bp open reading frame, and encodes a protein with 877 amino acid residues. The amino acid sequence of the C. carpio CAST gene was 88, 80, and 59% identical to the sequences observed in grass carp, zebrafish, and other fish, respectively. The C. carpio CAST was observed to contain four conserved domains with 54 serine phosphorylation loci, 28 threonine phosphorylation loci, 1 tyrosine phosphorylation loci, and 6 specific protein kinase C phosphorylation loci. The CAST gene showed widespread expression in different tissues of C. carpio. Surprisingly, the relative expression of the CAST transcript in the muscle and heart tissues of C. carpio was significantly higher than in other tissues (P < 0.01).

Physical and Clinical Evaluation of Hip Spica Cast applied with Three-slab Technique using Fibreglass Material

PubMed Central

Bitar, KM; Ferdhany, ME; Saw, A

2016-01-01

Introduction: Hip spica casting is an important component of treatment for developmental dysplasia of the hip (DDH) and popular treatment method for femur fractures in children. Breakage at the hip region is a relatively common problem of this cast. We have developed a three-slab technique of hip spica application using fibreglass as the cast material. The purpose of this review was to evaluate the physical durability of the spica cast and skin complications with its use. Methodology: A retrospective review of children with various conditions requiring hip spica immobilisation which was applied using our method. Study duration was from 1st of January 2014 until 31st December 2015. Our main outcomes were cast breakage and skin complications. For children with hip instability, the first cast would be changed after one month, and the second cast about two months later. Results: Twenty-one children were included, with an average age of 2.2 years. The most common indication for spica immobilisation was developmental dysplasia of the hip. One child had skin irritation after spica application. No spica breakage was noted. Conclusion: This study showed that the three-slab method of hip spica cast application using fibreglass material was durable and safe with low risk of skin complications. PMID:28553442

Hands-Off and Hands-On Casting Consistency of Amputee below Knee Sockets Using Magnetic Resonance Imaging

PubMed Central

Rowe, Philip

2013-01-01

Residual limb shape capturing (Casting) consistency has a great influence on the quality of socket fit. Magnetic Resonance Imaging was used to establish a reliable reference grid for intercast and intracast shape and volume consistency of two common casting methods, Hands-off and Hands-on. Residual limbs were cast for twelve people with a unilateral below knee amputation and scanned twice for each casting concept. Subsequently, all four volume images of each amputee were semiautomatically segmented and registered to a common coordinate system using the tibia and then the shape and volume differences were calculated. The results show that both casting methods have intra cast volume consistency and there is no significant volume difference between the two methods. Inter- and intracast mean volume differences were not clinically significant based on the volume of one sock criteria. Neither the Hands-off nor the Hands-on method resulted in a consistent residual limb shape as the coefficient of variation of shape differences was high. The resultant shape of the residual limb in the Hands-off casting was variable but the differences were not clinically significant. For the Hands-on casting, shape differences were equal to the maximum acceptable limit for a poor socket fit. PMID:24348164

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

PubMed

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

2015-05-01

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

Hands-off and hands-on casting consistency of amputee below knee sockets using magnetic resonance imaging.

PubMed

Safari, Mohammad Reza; Rowe, Philip; McFadyen, Angus; Buis, Arjan

2013-01-01

Residual limb shape capturing (Casting) consistency has a great influence on the quality of socket fit. Magnetic Resonance Imaging was used to establish a reliable reference grid for intercast and intracast shape and volume consistency of two common casting methods, Hands-off and Hands-on. Residual limbs were cast for twelve people with a unilateral below knee amputation and scanned twice for each casting concept. Subsequently, all four volume images of each amputee were semiautomatically segmented and registered to a common coordinate system using the tibia and then the shape and volume differences were calculated. The results show that both casting methods have intra cast volume consistency and there is no significant volume difference between the two methods. Inter- and intracast mean volume differences were not clinically significant based on the volume of one sock criteria. Neither the Hands-off nor the Hands-on method resulted in a consistent residual limb shape as the coefficient of variation of shape differences was high. The resultant shape of the residual limb in the Hands-off casting was variable but the differences were not clinically significant. For the Hands-on casting, shape differences were equal to the maximum acceptable limit for a poor socket fit.

Objective assessment of plaster cast quality in pediatric distal forearm fractures: Is there an optimal index?

PubMed

Labronici, Pedro José; Ferreira, Leonardo Termis; Dos Santos Filho, Fernando Claudino; Pires, Robinson Esteves Santos; Gomes, Davi Coutinho Fonseca Fernandes; da Silva, Luiz Henrique Penteado; Gameiro, Vinicius Schott

2017-02-01

Several so-called casting indices are available for objective evaluation of plaster cast quality. The present study sought to investigate four of these indices (gap index, padding index, Canterbury index, and three-point index) as compared to a reference standard (cast index) for evaluation of plaster cast quality after closed reduction of pediatric displaced distal forearm fractures. Forty-three radiographs from patients with displaced distal forearm fractures requiring manipulation were reviewed. Accuracy, sensitivity, specificity, false-positive probability, false-negative probability, positive predictive value, negative predictive value, positive likelihood ratio, and negative likelihood ratio were calculated for each of the tested indices. Comparison among indices revealed diagnostic agreement in only 4.7% of cases. The strongest correlation with the cast index was found for the gap index, with a Spearman correlation coefficient of 0.94. The gap index also displayed the best agreement with the cast index, with both indices yielding the same result in 79.1% of assessments. When seeking to assess plaster cast quality, the cast index and gap index should be calculated; if both indices agree, a decision on quality can be made. If the cast and gap indices disagree, the padding index can be calculated as a tiebreaker, and the decision based on the most frequent of the three results. Calculation of the three-point index and Canterbury index appears unnecessary. Copyright © 2016 Elsevier Ltd. All rights reserved.

Evaluation of cast creep occurring during simulated clubfoot correction

PubMed Central

Cohen, Tamara L; Altiok, Haluk; Wang, Mei; McGrady, Linda M; Krzak, Joseph; Graf, Adam; Tarima, Sergey; Smith, Peter A; Harris, Gerald, F

2016-01-01

The Ponseti method is a widely accepted and highly successful conservative treatment of pediatric clubfoot involving weekly manipulations and cast applications. Qualitative assessments have indicated the potential success of the technique with cast materials other than standard plaster of Paris. However, guidelines for clubfoot correction based on the mechanical response of these materials have yet to be investigated. The current study sought to characterize and compare the ability of three standard cast materials to maintain the Ponseti corrected foot position by evaluating cast creep response. A dynamic cast testing device, built to model clubfoot correction, was wrapped in plaster-of-Paris, semi-rigid fiberglass, and rigid fiberglass. Three-dimensional motion responses to two joint stiffnesses were recorded. Rotational creep displacement and linearity of the limb-cast composite were analyzed. Minimal change in position over time was found for all materials. Among cast materials, the rotational creep displacement was significantly different (p < 0.0001). The most creep displacement occurred in the plaster-of-Paris (2.0 degrees), then the semi-rigid fiberglass (1.0 degrees), and then the rigid fiberglass (0.4 degrees). Torque magnitude did not affect creep displacement response. Analysis of normalized rotation showed quasi—linear viscoelastic behavior. This study provided a mechanical evaluation of cast material performance as used for clubfoot correction. Creep displacement dependence on cast material and insensitivity to torque were discovered. This information may provide a quantitative and mechanical basis for future innovations for clubfoot care. PMID:23636764

Evaluation of the marginal fit of metal copings fabricated on three different marginal designs using conventional and accelerated casting techniques: an in vitro study.

PubMed

Vaidya, Sharad; Parkash, Hari; Bhargava, Akshay; Gupta, Sharad

2014-01-01

Abundant resources and techniques have been used for complete coverage crown fabrication. Conventional investing and casting procedures for phosphate-bonded investments require a 2- to 4-h procedure before completion. Accelerated casting techniques have been used, but may not result in castings with matching marginal accuracy. The study measured the marginal gap and determined the clinical acceptability of single cast copings invested in a phosphate-bonded investment with the use of conventional and accelerated methods. One hundred and twenty cast coping samples were fabricated using conventional and accelerated methods, with three finish lines: Chamfer, shoulder and shoulder with bevel. Sixty copings were prepared with each technique. Each coping was examined with a stereomicroscope at four predetermined sites and measurements of marginal gaps were documented for each. A master chart was prepared for all the data and was analyzed using Statistical Package for the Social Sciences version. Evidence of marginal gap was then evaluated by t-test. Analysis of variance and Post-hoc analysis were used to compare two groups as well as to make comparisons between three subgroups . Measurements recorded showed no statistically significant difference between conventional and accelerated groups. Among the three marginal designs studied, shoulder with bevel showed the best marginal fit with conventional as well as accelerated casting techniques. Accelerated casting technique could be a vital alternative to the time-consuming conventional casting technique. The marginal fit between the two casting techniques showed no statistical difference.

Comparative Evaluation of Conventional and Accelerated Castings on Marginal Fit and Surface Roughness

PubMed Central

Jadhav, Vivek Dattatray; Motwani, Bhagwan K.; Shinde, Jitendra; Adhapure, Prasad

2017-01-01

Aims: The aim of this study was to evaluate the marginal fit and surface roughness of complete cast crowns made by a conventional and an accelerated casting technique. Settings and Design: This study was divided into three parts. In Part I, the marginal fit of full metal crowns made by both casting techniques in the vertical direction was checked, in Part II, the fit of sectional metal crowns in the horizontal direction made by both casting techniques was checked, and in Part III, the surface roughness of disc-shaped metal plate specimens made by both casting techniques was checked. Materials and Methods: A conventional technique was compared with an accelerated technique. In Part I of the study, the marginal fit of the full metal crowns as well as in Part II, the horizontal fit of sectional metal crowns made by both casting techniques was determined, and in Part III, the surface roughness of castings made with the same techniques was compared. Statistical Analysis Used: The results of the t-test and independent sample test do not indicate statistically significant differences in the marginal discrepancy detected between the two casting techniques. Results: For the marginal discrepancy and surface roughness, crowns fabricated with the accelerated technique were significantly different from those fabricated with the conventional technique. Conclusions: Accelerated casting technique showed quite satisfactory results, but the conventional technique was superior in terms of marginal fit and surface roughness. PMID:29042726

The Design of 3D-Printed Lattice-Reinforced Thickness-Varying Shell Molds for Castings.

PubMed

Shangguan, Haolong; Kang, Jinwu; Yi, Jihao; Zhang, Xiaochuan; Wang, Xiang; Wang, Haibin; Huang, Tao

2018-03-30

3D printing technologies have been used gradually for the fabrication of sand molds and cores for castings, even though these molds and cores are dense structures. In this paper, a generation method for lattice-reinforced thickness-varying shell molds is proposed and presented. The first step is the discretization of the STL (Stereo Lithography) model of a casting into finite difference meshes. After this, a shell is formed by surrounding the casting with varying thickness, which is roughly proportional to the surface temperature distribution of the casting that is acquired by virtually cooling it in the environment. A regular lattice is subsequently constructed to support the shell. The outside surface of the shell and lattice in the cubic mesh format is then converted to STL format to serve as the external surface of the new shell mold. The internal surface of the new mold is the casting's surface with the normals of all of the triangles in STL format reversed. Experimental verification was performed on an Al alloy wheel hub casting. Its lattice-reinforced thickness-varying shell mold was generated by the proposed method and fabricated by the binder jetting 3D printing. The poured wheel hub casting was sound and of good surface smoothness. The cooling rate of the wheel hub casting was greatly increased due to the shell mold structure. This lattice-reinforced thickness-varying shell mold generation method is of great significance for mold design for castings to achieve cooling control.

A novel use of QR code stickers after orthopaedic cast application.

PubMed

Gough, A T; Fieraru, G; Gaffney, Pav; Butler, M; Kincaid, R J; Middleton, R G

2017-07-01

INTRODUCTION We present a novel solution to ensure that information and contact details are always available to patients while in cast. An information sticker containing both telephone numbers and a Quick Response (QR) code is applied to the cast. When scanned with a smartphone, the QR code loads the plaster team's webpage. This contains information and videos about cast care, complications and enhancing recovery. METHODS A sticker was designed and applied to all synthetic casts fitted in our fracture clinic. On cast removal, patients completed a questionnaire about the sticker. A total of 101 patients were surveyed between November 2015 and February 2016. The questionnaire comprised ten binary choice questions. RESULTS The vast majority (97%) of patients had the sticker still on their cast when they returned to clinic for cast removal. Eighty-four per cent of all patients felt reassured by the presence of the QR code sticker. Nine per cent used the contact details on the cast to seek advice. Over half (56%) had a smartphone and a third (33%) of these scanned the QR code. Of those who scanned the code, 95% found the information useful. CONCLUSIONS This study indicates that use of a QR code reassures patients and is an effective tool in the proactive management of potential cast problems. The QR code sticker is now applied to all casts across our trust. In line with NHS England's Five Year Forward View calling for enhanced use of smartphone technology, our trust is continuing to expand its portfolio of patient information accessible via QR codes. Other branches of medicine may benefit from incorporating QR codes as portals to access such information.

Cardiovascular cast model fabrication and casting effectiveness evaluation in fetus with severe congenital heart disease or normal heart.

PubMed

Wang, Yu; Cao, Hai-yan; Xie, Ming-xing; He, Lin; Han, Wei; Hong, Liu; Peng, Yuan; Hu, Yun-fei; Song, Ben-cai; Wang, Jing; Wang, Bin; Deng, Cheng

2016-04-01

To investigate the application and effectiveness of vascular corrosion technique in preparing fetal cardiovascular cast models, 10 normal fetal heart specimens with other congenital disease (control group) and 18 specimens with severe congenital heart disease (case group) from induced abortions were enrolled in this study from March 2013 to June 2015 in our hospital. Cast models were prepared by injecting casting material into vascular lumen to demonstrate real geometries of fetal cardiovascular system. Casting effectiveness was analyzed in terms of local anatomic structures and different anatomical levels (including overall level, atrioventricular and great vascular system, left-sided and right-sided heart), as well as different trimesters of pregnancy. In our study, all specimens were successfully casted. Casting effectiveness analysis of local anatomic structures showed a mean score from 1.90±1.45 to 3.60±0.52, without significant differences between case and control groups in most local anatomic structures except left ventricle, which had a higher score in control group (P=0.027). Inter-group comparison of casting effectiveness in different anatomical levels showed no significant differences between the two groups. Intra-group comparison also revealed undifferentiated casting effectiveness between atrioventricular and great vascular system, or left-sided and right-sided heart in corresponding group. Third-trimester group had a significantly higher perfusion score in great vascular system than second-trimester group (P=0.046), while the other anatomical levels displayed no such difference. Vascular corrosion technique can be successfully used in fabrication of fetal cardiovascular cast model. It is also a reliable method to demonstrate three-dimensional anatomy of severe congenital heart disease and normal heart in fetus.

Effect of pressure difference on the quality of titanium casting.

PubMed

Watanabe, I; Watkins, J H; Nakajima, H; Atsuta, M; Okabe, T

1997-03-01

In casting titanium using a two-compartment casting machine, Herø et al. (1993) reported that the pressure difference between the melting chamber and the mold chamber affected the soundness of the castings. This study tested the hypothesis that differences in pressure produce castings with various amounts of porosity and different mechanical properties values. Plastic dumbbell-shaped patterns were invested with an alumina-based, phosphate-bonded investment material. Both chambers of the casting machine were evacuated to 6 x 10(-2) torr; the argon pressure difference was then adjusted to either 50, 150, 300, or 450 torr. The porosity of the cast specimens was determined by x-ray radiography and quantitative image analysis. Tensile strength and elongation were measured by means of a universal testing machine at a strain rate of 1.7 x 10(-4)/s. The fractured surfaces were examined by SEM. Changes in Vickers hardness with depth from the cast surface were measured on polished cross-sections of the specimens. Raising the argon pressure difference to 300 and 450 torr caused a significant increase in internal porosity and a resultant decrease in the engineering tensile strength and elongation. The highest tensile strength (approximately 540 MPa), elongation (approximately 10%), bulk hardness (HV50g 209), and lowest porosity level (approximately 0.8%) occurred in the specimens cast at 150 torr. Turbulence of the metal during casting was thought to be responsible for the increase in porosity levels with the increase in argon pressure difference. By choosing an argon pressure difference (around 150 torr) suitable for this geometry, we could produce castings which have adequate mechanical properties and low porosity levels.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nick Cannell; Dr. Mark Samonds; Adi Sholapurwalla

The investment casting process is an expendable mold process where wax patterns of the part and rigging are molded, assembled, shelled and melted to produce a ceramic mold matching the shape of the component to be cast. Investment casting is an important manufacturing method for critical parts because of the ability to maintain dimensional shape and tolerances. However, these tolerances can be easily exceeded if the molding components do not maintain their individual shapes well. In the investment casting process there are several opportunities for the final casting shape to not maintain the intended size and shape, such as shrinkagemore » of the wax in the injection tool, the modification of the shape during shell heating, and with the thermal shrink and distortion in the casting process. Studies have been completed to look at the casting and shell distortions through the process in earlier phases of this project. Dr. Adrian Sabau at Oak Ridge National Labs performed characterizations and validations of 17-4 PH stainless steel in primarily fused silica shell systems with good agreement between analysis results and experimental data. Further tasks provided material property measurements of wax and methodology for employing a viscoelastic definition of wax materials into software. The final set of tasks involved the implementation of the findings into the commercial casting analysis software ProCAST, owned and maintained by ESI Group. This included: o the transfer of the wax material property data from its raw form into separate temperature-dependent thermophysical and mechanical property datasets o adding this wax material property data into an easily viewable and modifiable user interface within the pre-processing application of the ProCAST suite, namely PreCAST o and validating the data and viscoelastic wax model with respect to experimental results« less

Spall behavior of cast iron with varying microstructures

NASA Astrophysics Data System (ADS)

Plume, Gifford; Rousseau, Carl-Ernst

2014-07-01

The spall strength of cast iron with varying microstructures has been investigated using plate impact at moderate speed. Stress history measurements were made with manganin stress gauges embedded between the back face of the specimen and a low impedance polycarbonate backing. Five separate cast irons were tested. Four of these consisted of gray cast iron with graphite in flake form, with three classified as Type VII A2 and the fourth containing a bimodal distribution of Types VII A4 and VII D8. The fifth casting consisted of ductile cast iron with graphite in nodular form, classified as Type I, size class 5. The spall strength for the Type VII A2 gray cast irons varied between 40 and 370 MPa, and that of the additional gray cast iron, between 410 and 490 MPa. The spall strength of the ductile cast iron fell within the range of 0.94-1.2 GPa. It is shown that the spall strength is linked to the damage level at the spall plane, where an increased level of tensile stress is required to generate higher levels of damage. Post mortem analysis was performed on the recovered samples, revealing the graphite phase to be the primary factor governing the spall fracture of cast irons, where crack nucleation is directly correlated to the debonding of graphite from the metal matrix. The average length of graphite found within a casting is linked to the material's strength, where strength increases as a function of decreasing length. The morphology and mean free path of graphite precipitates further govern the subsequent coalescence of initiated cracks to form a complete fracture plane. In cases where graphite spacing is large, increased energy level is required to complete the fracture process. A secondary factor governing the spall fracture of cast irons has also been linked to the microstructure of the metal matrix, with pearlite yielding higher spall strengths than free ferrite.

Effect of surface contamination on adhesive bonding of cast pure titanium and Ti-6Al-4V alloy.

PubMed

Watanabe, I; Watanabe, E; Yoshida, K; Okabe, T

1999-03-01

There is little information regarding bond strengths of resin cements to cast titanium surfaces contaminated by investment material. This study examined the effect of surface contamination on the shear bond strength of resin cements to cast titanium and Ti-6Al-4V alloy. Two types of disks were cast from commercially pure titanium (CP-Ti) and Ti-6Al-4V alloy ingots using an argon-arc pressure casting unit and a phosphate-bonded Al2 O3 /LiAlSiO6 investment. After casting, disks were subjected to 3 surface treatments: (1) cast surface sandblasted (50 microm-sized Al2 O3 ) for 30 seconds; (2) metal surface sanded with silicon-carbide paper (600 grit) after grinding the contaminated cast surface (approximately 200 microm in thickness); and (3) metal surface sandblasted for 30 seconds after treatment 2. Surface structures were examined after each treatment with SEM and optical microscopy. Each type of disk was then bonded with 2 types of luting materials. Bonded specimens were subjected to thermocycling for up to 50,000 cycles, and shear bond strengths were determined after 0 (baseline) and 50,000 thermocycles. Results were statistically analyzed with 3-way ANOVA (P <.05). Microscopic observation of cast CP-Ti and Ti-6Al-4V exhibited noticeable structures on the cast surfaces apparently contaminated with investment material. However, there were no statistical differences (P >.05) in the bond strengths of both cements between contaminated (treatment 1) and uncontaminated surfaces (treatment 3) for both metals at baseline and after 50,000 thermocycles. The bond strength of specimens sanded with silicon-carbide paper (treatment 2) deteriorated dramatically after 50,000 thermocycles. Contamination of the cast metal surfaces by elements of the investment during casting did not affect bond strengths of the luting materials to CP-Ti and Ti-6Al-4V.

Effects of setting under air pressure on the number of surface pores and irregularities of dental investment materials.

PubMed

Tourah, Anita; Moshaverinia, Alireza; Chee, Winston W

2014-02-01

Surface roughness and irregularities are important properties of dental investment materials that can affect the fit of a restoration. Whether setting under air pressure affects the surface irregularities of gypsum-bonded and phosphate-bonded investment materials is unknown. The purpose of this study was to investigate the effect of air pressure on the pore size and surface irregularities of investment materials immediately after pouring. Three dental investments, 1 gypsum-bonded investment and 2 phosphate-bonded investments, were investigated. They were vacuum mixed according to the manufacturers' recommendations, then poured into a ringless casting system. The prepared specimens were divided into 2 groups: 1 bench setting and the other placed in a pressure pot at 172 kPa. After 45 minutes of setting, the rings were removed and the investments were cut at a right angle to the long axis with a diamond disk. The surfaces of the investments were steam cleaned, dried with an air spray, and observed with a stereomicroscope. A profilometer was used to evaluate the surface roughness (μm) of the castings. The number of surface pores was counted for 8 specimens from each group and the means and standard deviations were reported. Two-way ANOVA was used to compare the data. Specimens that set under atmospheric air pressure had a significantly higher number of pores than specimens that set under increased pressure (P<.05). No statistically significant differences for surface roughness were found (P=.078). Also, no significant difference was observed among the 3 different types of materials tested (P>.05). Specimens set under positive pressure in a pressure chamber presented fewer surface bubbles than specimens set under atmospheric pressure. Positive pressure is effective and, therefore, is recommended for both gypsum-bonded and phosphate-bonded investment materials. Copyright © 2014 Editorial Council for the Journal of Prosthetic Dentistry. Published by Mosby, Inc. All rights reserved.

Development of an expert system for the simulation model for casting metal substructure of a metal-ceramic crown design.

PubMed

Matin, Ivan; Hadzistevic, Miodrag; Vukelic, Djordje; Potran, Michal; Brajlih, Tomaz

2017-07-01

Nowadays, the integrated CAD/CAE systems are favored solutions for the design of simulation models for casting metal substructures of metal-ceramic crowns. The worldwide authors have used different approaches to solve the problems using an expert system. Despite substantial research progress in the design of experts systems for the simulation model design and manufacturing have insufficiently considered the specifics of casting in dentistry, especially the need for further CAD, RE, CAE for the estimation of casting parameters and the control of the casting machine. The novel expert system performs the following: CAD modeling of the simulation model for casting, fast modeling of gate design, CAD eligibility and cast ability check of the model, estimation and running of the program code for the casting machine, as well as manufacturing time reduction of the metal substructure. The authors propose an integration method using common data model approach, blackboard architecture, rule-based reasoning and iterative redesign method. Arithmetic mean roughness values was determinated with constant Gauss low-pass filter (cut-off length of 2.5mm) according to ISO 4287 using Mahr MARSURF PS1. Dimensional deviation between the designed model and manufactured cast was determined using the coordinate measuring machine Zeiss Contura G2 and GOM Inspect software. The ES allows for obtaining the castings derived roughness grade number N7. The dimensional deviation between the simulation model of the metal substructure and the manufactured cast is 0.018mm. The arithmetic mean roughness values measured on the casting substructure are from 1.935µm to 2.778µm. The realized developed expert system with the integrated database is fully applicable for the observed hardware and software. Values of the arithmetic mean roughness and dimensional deviation indicate that casting substructures are surface quality, which is more than enough and useful for direct porcelain veneering. The manufacture of the substructure shows that the proposed ES allows the improvement of the design process while reducing the manufacturing time. Copyright © 2017 Elsevier B.V. All rights reserved.

The therapeutic characteristics of serial casting on congenital scoliosis: a comparison with non-congenital cases from a single-center experience.

PubMed

Cao, Jun; Zhang, Xue-Jun; Sun, Ning; Sun, Lin; Guo, Dong; Qi, Xin-Yu; Bai, Yun-Song; Sun, Bao-Sheng

2017-04-04

The therapeutic efficacy of serial casting on idiopathic scoliosis has been gradually documented. However, literatures on serial casting for congenital scoliosis (CS) remain extremely rare. This paper aimed to compare the treatment outcomes of serial casting between CS and non-CS patients to comprehensively evaluate the therapeutic characteristics of serial casting on CS patients. A total of 23 early-onset scoliosis cases were included and divided into congenital scoliosis (CS, n = 8) and non-congenital group (non-CS, n = 15). Therapeutic outcomes including the major curve Cobb angle, thoracic kyphosis angle, lumbar lodosis angle, and thoracic spine growing rate were compared between groups at precast, after the first cast, and at the latest follow-up, respectively. All patients received the first cast at the age of 3.25 ± 1.20 years and 5.70 ± 1.18 times of cast corrections. The average casting time was 17.17 ± 3.38 months, and the mean follow-up time was 23.91 ± 12.28 months. Both CS and non-CS groups had significant decrease in Cobb angle after the first cast and at the latest follow-up (all P < 0.05). Cobb angle was significantly lower in non-CS group than in CS group at both time points (all P < 0.01). The correction rate of Cobb angle was significantly higher in non-CS group than in CS group (around 50 vs. 20%, both P < 0.01). The mean thoracic growth rate was significantly lower in CS group than in non-CS group (0.72 ± 0.20 vs. 1.42 ± 0.22 cm/year, P < 0.001). At the latest follow-up, there are 2 cases receiving growing rod surgery, 8 cases wearing a brace, and 13 cases continuing serial casting. Although the therapeutic efficacy of casting on CS patients is not as good as that on non-CS patients, casting is still an efficient treatment option for CS patients to delay the need for initial surgery.

Accuracy and precision of occlusal contacts of stereolithographic casts mounted by digital interocclusal registrations.

PubMed

Krahenbuhl, Jason T; Cho, Seok-Hwan; Irelan, Jon; Bansal, Naveen K

2016-08-01

Little peer-reviewed information is available regarding the accuracy and precision of the occlusal contact reproduction of digitally mounted stereolithographic casts. The purpose of this in vitro study was to evaluate the accuracy and precision of occlusal contacts among stereolithographic casts mounted by digital occlusal registrations. Four complete anatomic dentoforms were arbitrarily mounted on a semi-adjustable articulator in maximal intercuspal position and served as the 4 different simulated patients (SP). A total of 60 digital impressions and digital interocclusal registrations were made with a digital intraoral scanner to fabricate 15 sets of mounted stereolithographic (SLA) definitive casts for each dentoform. After receiving a total of 60 SLA casts, polyvinyl siloxane (PVS) interocclusal records were made for each set. The occlusal contacts for each set of SLA casts were measured by recording the amount of light transmitted through the interocclusal records. To evaluate the accuracy between the SP and their respective SLA casts, the areas of actual contact (AC) and near contact (NC) were calculated. For precision analysis, the coefficient of variation (CoV) was used. The data was analyzed with t tests for accuracy and the McKay and Vangel test for precision (α=.05). The accuracy analysis showed a statistically significant difference between the SP and the SLA cast of each dentoform (P<.05). For the AC in all dentoforms, a significant increase was found in the areas of actual contact of SLA casts compared with the contacts present in the SP (P<.05). Conversely, for the NC in all dentoforms, a significant decrease was found in the occlusal contact areas of the SLA casts compared with the contacts in the SP (P<.05). The precision analysis demonstrated the different CoV values between AC (5.8 to 8.8%) and NC (21.4 to 44.6%) of digitally mounted SLA casts, indicating that the overall precision of the SLA cast was low. For the accuracy evaluation, statistically significant differences were found between the occlusal contacts of all digitally mounted SLA casts groups, with an increase in AC values and a decrease in NC values. For the precision assessment, the CoV values of the AC and NC showed the digitally articulated cast's inability to reproduce the uniform occlusal contacts. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by Elsevier Inc. All rights reserved.

A simple technique to prolong molding time during application of a fiberglass cast: An in vitro study

PubMed Central

Ayzenberg, Mark; Narvaez, Michael; Raphael, James

2018-01-01

Casting is routinely used for acute and post-operative immobilization and remains a cornerstone in the non-operative management of fractures and deformities. The application of a properly fitted and wellmolded cast, especially for a trainee, can be challenging. We present a simple method of prolonging cure time of fiberglass cast — placing ice in the dip water. Eight-ply, fiveinch fiberglass cast was circumferentially applied to an aluminum-wrapped cardboard cylinder. An electronic, 2-channel temperature sensor (TR-71wf Temp Logger, T&D Corporation, Matsumoto, Japan), accurate to 0.1ºC and accurate to ±0.3ºC, was placed between the fourth and fifth layers of fiberglass. Thirty total casts were tested using 9±1ºC (cold), 22±1ºC (ambient), and 36±1ºC (warm) dip water. Room temperature was maintained at 24±1ºC. Cast temperatures were measured during the exothermic reaction generated by the cast curing. Peak temperatures and cure times were recorded. Cure time was defined as the point of downward deflection on the timetemperature curve immediately after peak. Cure and peak temperatures were compared among groups using analysis of variance. Mean cure time was 3.5±0.1 minutes for warm water, 5.0±0.4 minutes for ambient water and 7.0±0.5 minutes for cold water. Peak temperature, measured between layers 4 and 5 of the cast material, was 36.6±0.8ºC for warm water, 31.1±1.4ºC for ambient water and 25.2±0.5ºC for cold water. Cold afforded, on average, an additional 2 minutes (40% increase) in cure time compared to ambient water and an additional 3.5 minutes (100% increase) compared to warm water. Cure time differences were significant (P<0.001) for all groups, as were peak temperature differences (P<0.001). Temperatures concerning for development of burns were never reached. Utilizing iced dip water when casting is a simple and effective method to prolong the time available for cast application. Orthopedic residents and trainees may find this useful in learning to fabricate a high quality cast. For the experienced orthopedic surgeon, this method eliminates the need to bridge longlimb casts and facilitates the application of complex casts. PMID:29770174

Vacuum force

NASA Astrophysics Data System (ADS)

Han, Yongquan

2015-03-01

To study on vacuum force, we must clear what is vacuum, vacuum is a space do not have any air and also ray. There is not exist an absolute the vacuum of space. The vacuum of space is relative, so that the vacuum force is relative. There is a certain that vacuum vacuum space exists. In fact, the vacuum space is relative, if the two spaces compared to the existence of relative vacuum, there must exist a vacuum force, and the direction of the vacuum force point to the vacuum region. Any object rotates and radiates. Rotate bend radiate- centripetal, gravity produced, relative gravity; non gravity is the vacuum force. Gravity is centripetal, is a trend that the objects who attracted wants to Centripetal, or have been do Centripetal movement. Any object moves, so gravity makes the object curve movement, that is to say, the radiation range curve movement must be in the gravitational objects, gravity must be existed in non vacuum region, and make the object who is in the region of do curve movement (for example: The earth moves around the sun), or final attracted in the form gravitational objects, and keep relatively static with attract object. (for example: objects on the earth moves but can't reach the first cosmic speed).

Quality criteria for pure titanium casting, laboratory soldering, intraoral welding, and a device to aid in making uncontaminated castings.

PubMed

Hruska, A R; Borelli, P

1991-10-01

Procedures for casting, laboratory soldering, and intraoral welding of titanium for dental restorations are described and illustrated. Pure titanium and titanium 6A1-4Va alloy castings may be used for virtually any prosthodontic rehabilitation as well as for implants, with the proper equipment and technique.

75 FR 75964 - Non-Malleable Cast Iron Pipe Fittings From the People's Republic of China: Extension of Time...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-12-07

... DEPARTMENT OF COMMERCE International Trade Administration [A-570-875] Non-Malleable Cast Iron Pipe...-malleable cast iron pipe fittings from the People's Republic of China (``PRC''). See Initiation of...-malleable cast iron pipe fittings from the PRC within the time limits mandated by section 751(a)(3)(A) of...

75 FR 54595 - Certain Iron Construction Castings From Brazil, Canada, and the People's Republic of China: Final...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-09-08

...] Certain Iron Construction Castings From Brazil, Canada, and the People's Republic of China: Final Results... construction castings from Brazil, Canada, and the People's Republic of China (PRC), pursuant to section 751(c... antidumping duty orders\\1\\ on certain iron construction castings from Brazil, Canada, and the PRC pursuant to...

Estimation of Heat Transfer Coefficient in Squeeze Casting of Magnesium Alloy AM60 by Experimental Polynomial Extrapolation Method

NASA Astrophysics Data System (ADS)

Sun, Zhizhong; Niu, Xiaoping; Hu, Henry

In this work, a different wall-thickness 5-step (with thicknesses as 3, 5, 8, 12, 20 mm) casting mold was designed, and squeeze casting of magnesium alloy AM60 was performed in a hydraulic press. The casting-die interfacial heat transfer coefficients (IHTC) in 5-step casting were determined based on experimental thermal histories data throughout the die and inside the casting which were recorded by fine type-K thermocouples. With measured temperatures, heat flux and IHTC were evaluated using the polynomial curve fitting method. The results show that the wall thickness affects IHTC peak values significantly. The IHTC value for the thick step is higher than that for the thin steps.

Method and apparatus for planar drag strip casting

DOEpatents

Powell, John C.; Campbell, Steven L.

1991-01-01

The present invention is directed to an improved process and apparatus for strip casting. The combination of a planar flow casting nozzle positioned back from the top dead center position with an attached nozzle extension, provides an increased level of casting control and quality. The nozzle extension provides a means of containing the molten pool above the rotating substrate to increase the control of molten metal at the edges of the strip and increase the range of coating thicknesses which may be produced. The level of molten metal in the containment means is regulated to be above the level of melt supplying the casting nozzle which produces a condition of planar drag flow with the casting substrate prior to solidification.

Method and apparatus for planar drag strip casting

DOEpatents

Powell, J.C.; Campbell, S.L.

1991-11-12

The present invention is directed to an improved process and apparatus for strip casting. The combination of a planar flow casting nozzle positioned back from the top dead center position with an attached nozzle extension, provides an increased level of casting control and quality. The nozzle extension provides a means of containing the molten pool above the rotating substrate to increase the control of molten metal at the edges of the strip and increase the range of coating thicknesses which may be produced. The level of molten metal in the containment means is regulated to be above the level of melt supplying the casting nozzle which produces a condition of planar drag flow with the casting substrate prior to solidification. 5 figures.

Benefit from NASA

NASA Image and Video Library

1998-01-01

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

Effect of cobalt on microstructure and properties of AlCr1.5CuFeNi2Cox high-entropy alloys

NASA Astrophysics Data System (ADS)

Kukshal, Vikas; Patnaik, Amar; Bhat, I. K.

2018-04-01

The present paper investigates the effect of Co addition on the alloying behaviour, microstructure and the resulting properties of cast AlCr1.5CuFeNi2Cox high-entropy alloys intended to be used for high temperature applications. The elements Al, Cr, Cu, Fe, Ni and Co (Purity > 99) weighing approximately 800 g was melted in a high temperature vacuum induction furnace. The microstructure, phase transformation, density, microhardness and compressive strength of the samples were analysed using x-ray diffraction (XRD), scanning electron microscopes (SEM), Vickers microhardness tester and universal Testing machine. The crystalline structure of the alloys exhibits simple FCC and BCC phases. The microstructures investigation of the alloys shows the segregation of copper in the interdendritic region resulting in Cu-rich FCC phase. The addition of Co further enhances the formation of FCC phase resulting in the decrease in micro hardness value of the alloys, which varies from 471 HV to 364 HV with increase in the cobalt content from x = 0 to x = 1 (molar ratio). The similar decreasing trend is also observed for the compressive strength of the alloys.

Fabrication of the Ti5Si3/Ti composite inoculants and its refining mechanism on pure titanium

NASA Astrophysics Data System (ADS)

Li, Nuo; Cui, Chunxiang; Liu, Shaungjin; Zhao, Long; Liu, Shuiqing

2017-03-01

The in situ Ti5Si3/Ti inoculants were successfully prepared by vacuum arc-melting and melt-spinning method. An efficient route by adding a small quantity of Ti5Si3/Ti inoculants to Ti melt has been first proposed to modify the coarse grains of as cast microstructure of pure titanium in this paper. It was found that the microstructure of ribbon inoculants was cellular structure that composed of Ti5Si3 and α-Ti phases. The grain refining effect of the inoculants was significantly improved with the adding ratio range from 0.2% to 0.5% in weight. With the increase of addition amount of inoculants on Ti melt, the tensile strength, yield strength and microhardness of pure titanium are significantly improved except elongation. The excellent grain refining effect can be attributed to the heterogeneous nucleation of the titanium grain on the precipitated Ti5Si3 phases in the Si-rich regions and the constitutional supercooling of Si in the Si-poverty regions. It is suggested that the in situ Ti5Si3/Ti inoculants is a promising inoculants for titanium alloys.

Single-crystal gallium nitride nanotubes.

PubMed

Goldberger, Joshua; He, Rongrui; Zhang, Yanfeng; Lee, Sangkwon; Yan, Haoquan; Choi, Heon-Jin; Yang, Peidong

2003-04-10

Since the discovery of carbon nanotubes in 1991 (ref. 1), there have been significant research efforts to synthesize nanometre-scale tubular forms of various solids. The formation of tubular nanostructure generally requires a layered or anisotropic crystal structure. There are reports of nanotubes made from silica, alumina, silicon and metals that do not have a layered crystal structure; they are synthesized by using carbon nanotubes and porous membranes as templates, or by thin-film rolling. These nanotubes, however, are either amorphous, polycrystalline or exist only in ultrahigh vacuum. The growth of single-crystal semiconductor hollow nanotubes would be advantageous in potential nanoscale electronics, optoelectronics and biochemical-sensing applications. Here we report an 'epitaxial casting' approach for the synthesis of single-crystal GaN nanotubes with inner diameters of 30-200 nm and wall thicknesses of 5-50 nm. Hexagonal ZnO nanowires were used as templates for the epitaxial overgrowth of thin GaN layers in a chemical vapour deposition system. The ZnO nanowire templates were subsequently removed by thermal reduction and evaporation, resulting in ordered arrays of GaN nanotubes on the substrates. This templating process should be applicable to many other semiconductor systems.

Nickel foam-supported polyaniline cathode prepared with electrophoresis for improvement of rechargeable Zn battery performance

NASA Astrophysics Data System (ADS)

Xia, Yang; Zhu, Derong; Si, Shihui; Li, Degeng; Wu, Sen

2015-06-01

Porous nickel foam is used as a substrate for the development of rechargeable zinc//polyaniline battery, and the cathode electrophoresis of PANI microparticles in non-aqueous solution is applied to the fabrication of Ni foam supported PANI electrode, in which the corrosion of the nickel foam substrate is prohibited. The Ni foam supported PANI cathode with high loading is prepared by PANI electrophoretic deposition, and followed by PANI slurry casting under vacuum filtration. The electrochemical charge storage performance for PANI material is significantly improved by using nickel foam substrate via the electrophoretic interlayer. The specific capacity of the nickel foam-PANI electrode with the electrophoretic layer is higher than the composite electrode without the electrophoretic layer, and the specific capacity of PANI supported by Ni foam reaches up to 183.28 mAh g-1 at the working current of 2.5 mA cm-2. The present electrophoresis deposition method plays the facile procedure for the immobilization of PANI microparticles onto the surface of non-platinum metals, and it becomes feasible to the use of the Ni foam supported PANI composite cathode for the Zn/PANI battery in weak acidic electrolyte.

27Al, 63Cu NMR spectroscopy and electrical transport in Heusler Cu-Mn-Al alloy powders

NASA Astrophysics Data System (ADS)

Nadutov, V. M.; Perekos, A. O.; Kokorin, V. V.; Trachevskii, V. V.; Konoplyuk, S. M.; Vashchuk, D. L.

2018-02-01

The ultrafine powder of the Heusler Cu-13,1Mn-12,6Al (wt.%) alloy produced by electrical spark dispersion (ESD) in ethanol and the pellets prepared by pressing of the powders and aged in various gas environment (air, Ar, vacuum) were studied by XRD, nuclear magnetic resonance, magnetic and electric transport methods. The constituent phases were identified as b.c.c. α-Cu-Mn-Al, f.c.c. γ-Cu-Mn-Al, Cu2MnAl, and oxides. The sizes of the coherently scattering domains (CSD) and the saturation magnetizations were in the range of 4-90 nm and 0-1.5 Am2/kg, respectively. 27Al and 63Cu NMR spectra of the powders and pellets have shown hyperfine structure caused by contributions from atomic nuclei of the constituent phases. The aging of pellets in different gas environments had effect on their phase composition but no effect on dispersion of the phases. In contrast to the as-cast alloy, electrical resistance of the pellets evidenced semiconducting behavior at elevated temperatures due to the presence of metal oxides formed on the surfaces of nanoparticles.

Effect of Processing Route on Strain Controlled Low Cycle Fatigue Behavior of Polycrystalline NiAl

NASA Technical Reports Server (NTRS)

Rao, K. Bhanu Sankara; Lerch, B. A.; Noebe, R. D.

1995-01-01

The present investigation examines the effects of manufacturing process on the total axial strain controlled low cycle fatigue behavior of polycrystalline NiAl at 1000 K, a temperature above the monotonic Brittle-to-Ductile Transition Temperature (BDTT). The nickel aluminide samples were produced by three different processing routes: hot isostatic pressing of pre- alloyed powders, extrusion of prealloyed powders, and extrusion of vacuum induction melted ingots. The LCF behavior of the cast plus extruded material was also determined at room temperature (below the BD77) for comparison to the high temperature data. The cyclic stress response, cyclic stress-strain behavior, and strain-life relationships were influenced by the alloy preparation technique and the testing temperature. Detailed characterization of the LCF tested samples was conducted by optical and electron microscopy to determine the variations in fracture and deformation modes and to determine any microstructural changes that occurred during LCF testing. The dependence of LCF properties on processing route was rationalized on the basis of starting microstructure, brittle-to-ductile transition temperature, deformation induced changes in the basic microstructure, deformation substructure, and synergistic interaction between the damage modes.

Fast emission spectroscopy for monitoring condensed carbon in detonation products of oxygen-deficient high explosives

NASA Astrophysics Data System (ADS)

Poeuf, Sandra; Baudin, Gerard; Genetier, Marc; Lefrançois, Alexandre; Cinnayya, Ashwin; Laurent, Jacquet

2017-06-01

A new thermochemical code, SIAME, dedicated to the study of high explosives, is currently being developed. New experimental data relative to the expansion of detonation products are required to validate the code, and a particular focus is made on solid carbon products. Two different high explosive formulations are used: a melt-cast one (RDX/TNT 60/40 % wt.) and a pressed one (HMX/VitonR 96/4 % wt.). The experimental setup allows the expansion of the products at pressures below 1 GPa in an inert medium (vacuum, helium, nitrogen and PMMA). The results of fast emission dynamic spectroscopy measurements used to monitor the detonation carbon products are reported. Two spectral signatures are identified: the first is associated to ionized gases and the second to carbon thermal radiation. The experimental spectral lines are compared with simulated spectra. The trajectory of the shock wave front is continuously recorded with a high frequency interferometer. Comparisons with numerical simulations on the hydrodynamic code Ouranoshave been done. These two measurements, using the different inert media, enable to make one step forward in the validation of the detonation products equation of state implemented in the SIAME code.

Surface Enhancement For Optical Plastics

NASA Astrophysics Data System (ADS)

Masso, Jon D.

1988-07-01

Optical plastics can be molded or cast to replicate traditional spherical and aspheric lenses. It is possible to obtain good optical quality, but often it is necessary or desirable to enhance the surface characteristics in a variety of ways. These include improving the abrasion resistance, chemical resistance, the addition of anti-fog, or anti-static characteristics, applying electrically conductive coatings, and applying coatings or selective absorbers for light and color control. Coatings may be entirely organic or organo-silanes applied by dipping or spinning. All dielectric coatings such as quartz abrasion resistant coatings or multilayer dielectric coatings for reflection reduction or enhancement may be applied by vacuum vapor deposition. This paper discusses a number of these coatings and surface treatments. The paper describes their characteristics and includes discussions of their durability and environmental stability. The adhesion of coatings to plastic substrate depends on the specific substrate and coating materials. Pretreatments or primers are used to promote good coating adhesion. A coating used for one purpose will generally affect other properties of the plastic and trade-offs are sometimes required. A description is given of several test methods which have been found useful in evaluating the quality of the various coatings.

Thermal processing of EVA encapsulants and effects of formulation additives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pern, F.J.; Glick, S.H.

1996-05-01

The authors investigated the in-situ processing temperatures and effects of various formulation additives on the formation of ultraviolet (UV) excitable chromophores, in the thermal lamination and curing of ethylene-vinyl acetate (EVA) encapsulants. A programmable, microprocessor-controlled, double-bag vacuum laminator was used to study two commercial as formulated EVA films, A9918P and 15295P, and solution-cast films of Elvaxrm (EVX) impregnated with various curing agents and antioxidants. The results show that the actual measured temperatures of EVA lagged significantly behind the programmed profiles for the heating elements and were affected by the total thermal mass loaded inside the laminator chamber. The antioxidant Naugardmore » P{trademark}, used in the two commercial EVA formulations, greatly enhances the formation of UV-excitable, short chromophores upon curing, whereas other tested antioxidants show little effect. A new curing agent chosen specifically for the EVA formulation modification produces little or no effect on chromophore formation, no bubbling problems in the glass/EVX/glass laminates, and a gel content of {approximately}80% when cured at programmed 155{degrees}C for 4 min. Also demonstrated is the greater discoloring effect with higher concentrations of curing-generated chromophores.« less

Thermal processing of EVA encapsulants and effects of formulation additives

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pern, F.J.; Glick, S.H.

1996-09-01

The authors investigated the in-situ processing temperatures and effects of various formulation additives on the formation of ultraviolet (UV) excitable chromophores in the thermal lamination and curing of ethylene-vinyl acetate (EVA) encapsulants. A programmable, microprocessor-controlled, double-bag vacuum laminator was used to study two commercial as-formulated EVA films. A9918P and 15295P, and solution-cast films of Elvax{trademark} (EVX) impregnated with various curing agents and antioxidants. The results show that the actual measured temperatures of EVA lagged significantly behind the programmed profiles for the heating elements and were affected by the total thermal mass loaded inside the laminator chamber. The antioxidant Naugard P{trademark},more » used in the two commercial EVA formulations, greatly enhances the formation of UV-excitable, short chromophores upon curing, whereas other tested antioxidants show little effect. A new curing agent chosen specifically for the EVA formulation modification produces little or no effect on chromophore formation, no bubbling problems in the glass/EVX/glass laminates, and a gel content of {approximately}80% when cured at programmed 155 C for 4 min. Also demonstrated is the greater discoloring effect with higher concentrations of curing-generated chromophores.« less

Comparison of cast materials for the treatment of congenital idiopathic clubfoot using the Ponseti method: a prospective randomized controlled trial

PubMed Central

Hui, Catherine; Joughin, Elaine; Nettel-Aguirre, Alberto; Goldstein, Simon; Harder, James; Kiefer, Gerhard; Parsons, David; Brauer, Carmen; Howard, Jason

2014-01-01

Background The Ponseti method of congenital idiopathic clubfoot correction has traditionally specified plaster of Paris (POP) as the cast material of choice; however, there are negative aspects to using POP. We sought to determine the influence of cast material (POP v. semirigid fibreglass [SRF]) on clubfoot correction using the Ponseti method. Methods Patients were randomized to POP or SRF before undergoing the Ponseti method. The primary outcome measure was the number of casts required for clubfoot correction. Secondary outcome measures included the number of casts by severity, ease of cast removal, need for Achilles tenotomy, brace compliance, deformity relapse, need for repeat casting and need for ancillary surgical procedures. Results We enrolled 30 patients: 12 randomized to POP and 18 to SRF. There was no difference in the number of casts required for clubfoot correction between the groups (p = 0.13). According to parents, removal of POP was more difficult (p < 0.001), more time consuming (p < 0.001) and required more than 1 method (p < 0.001). At a final follow-up of 30.8 months, the mean times to deformity relapse requiring repeat casting, surgery or both were 18.7 and 16.4 months for the SRF and POP groups, respectively. Conclusion There was no significant difference in the number of casts required for correction of clubfoot between the 2 materials, but SRF resulted in a more favourable parental experience, which cannot be ignored as it may have a positive impact on psychological well-being despite the increased cost associated. PMID:25078929

Pacman in the sky with shadows: the effect of cast shadows on the perceptual completion of occluded figures by chimpanzees and humans.

PubMed

Tomonaga, Masaki; Imura, Tomoko

2010-07-08

Humans readily perceive whole shapes as intact when some portions of these shapes are occluded by another object. This type of amodal completion has also been widely reported among nonhuman animals and is related to pictorial depth perception. However, the effect of a cast shadow, a critical pictorial-depth cue for amodal completion has been investigated only rarely from the comparative-cognitive perspective. In the present study, we examined this effect in chimpanzees and humans. Chimpanzees were slower in responding to a Pacman target with an occluding square than to the control condition, suggesting that participants perceptually completed the whole circle. When a cast shadow was added to the square, amodal completion occurred in both species. On the other hand, however, critical differences between the species emerged when the cast shadow was added to the Pacman figure, implying that Pacman was in the sky casting a shadow on the square. The cast shadow prevented, to a significant extent, compulsory amodal completion in humans, but had no effect on chimpanzees. These results suggest that cast shadows played a critical role in enabling humans to infer the spatial relationship between Pacman and the square. For chimpanzees, however, a cast shadow may be perceived as another "object". A limited role for cast shadows in the perception of pictorial depth has also been reported with respect to human cognitive development. Further studies on nonhuman primates using a comparative-developmental perspective will clarify the evolutionary origin of the role of cast shadows in visual perception.

Reproducibility of the index of orthognathic functional treatment need scores derived from plaster study casts and their three-dimensional digital equivalents: a pilot study.

PubMed

McCrory, Emma; McGuinness, Niall Jp; Ulhaq, Aman

2018-06-01

To determine the reproducibility of Index of Orthognathic Functional Treatment Need (IOFTN) scores derived from plaster casts and their three-dimensional (3D) digital equivalents. Pilot study, prospective analytical. UK hospital orthodontic department. Thirty casts and their digital equivalents, representing the pre-treatment malocclusions of patients requiring orthodontic-orthognathic surgical treatment, were scored by four clinicians using IOFTN. Casts were scanned using a 3Shape digital scanner and 3D models produced using OrthoAnalyzer TM (3Shape Ltd, Copenhagen, Denmark). Examiners independently determined the IOFTN scores for the casts and digital models, to test their inter- and intra-operator reliability using weighted Kappa scores. Intra-operator agreement with IOFTN major categories (1-5: treatment need) was very good for plaster casts (0.83-0.98) and good-very good for digital models (0.78-0.83). Inter-operator agreement was moderate-very good for casts (0.58-0.82) and good-very good for digital models (0.65-0.92). Intra-operator agreement with IOFTN sub-categories (1-14: feature of malocclusion) was good-very good for casts (0.70-0.97) and digital models (0.80-0.94). Inter-operator agreement was moderate-good for casts (0.53-0.77); and moderate-very good for the digital models (0.58-0.90). Digital models are an acceptable alternative to plaster casts for examining the malocclusion of patients requiring combined orthodontic-orthognathic surgical treatment and determining treatment need.

Genetic profile based upon 15 microsatellites of four caste groups of the eastern Indian state, Bihar.

PubMed

Ashma, R; Kashyap, V K

2003-01-01

The formation of caste groups among the Hindu community and the practice of endogamy exert a great impact on the genetic structure and diversity of the Indian population. Allele frequency data of 15 microsatellite loci clearly portray the genetic diversity and relatedness among four socio-culturally advanced caste groups: Brahmin, Bhumihar, Rajput and Kayasth of Caucasoid ethnicity of Bihar. The study seeks to understand the impact of the man-made caste system on the genetic profile of the four major caste groups of Bihar. Computation of average heterozygosity, most frequent allele, allele diversity and coefficient of gene differentiation (Gst), along with genetic distance (DA)and principal coordinate analysis were performed to assess intra-population and inter-population diversity. The average Gst value for all the loci was 0.012 +/- 0.0033, and the level of average heterozygosity was approximately 75.5%, indicating genetic similarity and intra-population diversity. Genetic distance (DA) values and the phylogenetic tree along with other higher caste groups of India indicate the relative distance between them. The present study clearly depicts the genetic profile of these caste groups, their inherent closeness in the past, and the impact of the imposed caste system that later restricted the gene flow. The study highlights the status of Bhumihar and Kayasth in the Hindu caste system. The former was found clustering with the Brahmin group (as expected, since Bhumihar is known to be a subclass of Brahmin), whereas the distance between the Brahmin and Kayasth caste groups was found to be large. North-eastern Indian Mongoloids form a separate cluster.

The influence of flushing time on the bonding quality of liquid white cast iron on the solid surface of similar material

NASA Astrophysics Data System (ADS)

Bandanadjaja, Beny; Purwadi, Wiwik; Idamayanti, Dewi; Lilansa, Noval; Hanaldi, Kus; Nurzaenal, Friya Kurnia

2018-05-01

Hard metal castings are widely used in the coal mill pulverizer as construction material for coal crushers. During its operation crushers and mills experience degradation caused by abrasion load. This research dealed with the surface overlaying of similiar material on the surface of white cast iron by mean of gravity casting. The die blank casting was preheated prior to the casting process of outer layer made of Ni-Hard white cast iron to guarantee bonding processes and avoid any crack. The preheating temperature of die blankin ther range of 500C up to 850C was set up to reach the interface temperature in the range of 887°C -1198°C and the flushing time was varied between 10-20 seconds. Studies carried on the microstructure of sample material revealed a formation of metallurgical bonding at the preheating temperature above 625 °C by pouring temperature ranging from 1438 °C to 1468 °C. Metallographical and chemical composition by mean of EDS examination were performed to observed the resut. This research concludes that the casting of Ni-Hard 1 overlay by applying gravity casting method can be done by preheating the surface of casting to 625 °C, interface temperature of 1150 °C, flushing time of 7 seconds and pouring temperature of 1430 °C. Excellent metallurgical bonding at the contact area between dieblank and overlay material has been achieved in which there is no parting line at the interface area to be observed.

Casting made simple using modified sprue design: an in vitro study.

PubMed

Baskaran, B Eswaran; Geetha Prabhu, K R; Prabhu, R; Krishna, G Phani; Eswaran, M A; Gajapathi, B

2014-01-01

Success in dental casting restorations for fixed partial dentures (FPDs) depends on the castability. Castability is described as the ability of an alloy to faithfully reproduce sharp detail and fine margins of a wax pattern. The goal of a prosthodontist is to provide the patient with restorations that fit precisely. Regardless of the alloy used for casting, the casting technique should yield a casted alloy, which should possess sufficient mass, surface hardness and minimal porosity after casting. Twenty patterns for casting were made from three-dimensional printed resin pattern simulating a 3 unit FPD and casted using modified sprue technique. Later test samples were cemented sequentially on stainless steel model using pressure indicating paste and evaluated for vertical marginal gap in eight predetermined reference areas. Marginal gap were measured in microns using Video Measuring System (VMS2010F-CIP Corporation, Korea). A portion of the axial wall of the cast abutments depicting premolar and molar were sectioned and embedded in acrylic resin and tested for micro hardness using Reichert Polyvar 2 Met Microhardness tester (Reichert, Austria) and porosity using Quantimet Image Analyzer (Quantimet Corporation London, England). The results obtained for marginal gap, micro hardness, and porosity of all test samples were tabulated, descriptive statistics were calculated and the values were found to be within the clinically acceptable range. The new sprue technique can be an alternative and convenient method for casting which would minimize metal wasting and less time consuming. However, further studies with same technique on various parameters are to be conducted for its broad acceptance.

Aluminum-fly ash metal matrix composites for automotive parts. [Reports for October 1 to December 1998, and January 31 to March 31, 1999

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weiss, David; Purgert, Robert; Rhudy, Richard

1999-04-21

Some highlights are: (1) Material development, process development, and part validation are occurring simultaneously on a fast track schedule. (2) Prior project activity has resulted in a program emphasis on three components--manifolds, mounting brackets, and motor mounts; and three casting techniques--squeeze casting, pressure die casting, and sand casting. (3) With the project focus, it appears possible to offer manifolds and mounting brackets for automotive qualification testing on a schedule in line with the PNGV Year 2004 goal. (4) Through an iterative process of fly ash treatment, MMC ingot preparation, foundry process refinement, and parts production, both foundries (Eck Industries andmore » Thompson Aluminum Casting Company) are addressing the pre-competitive issues of: (a) Optimum castability with fly ash shapes and sizes; (b) Best mechanical properties derived from fly ash shapes and sizes; (c) Effective fly ash classification processes; (d) Mechanical properties resulting from various casting processes and fly ash formulations. Eck and TAC continued experiments with batch ingot provided by both Eck and the University of Wisconsin at Milwaukee. Castings were run that contained varying amounts of fly ash and different size fractions. Components were cast using cenosphere material to ascertain the effects of squeeze casting and to determine whether the pressure would break the cenospheres. Test parts are currently being machined into substandard test bars for mechanical testing. Also, the affect of heat treatments on ashalloy are being studied through comparison to two lots, one heat treated and one in the ''as cast'' condition.« less

Aluminum-fly ash metal matrix composites for automotive parts. [Reports for October 1 to December 31, 1999, and January 1 - to March 31, 2000

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weiss, David; Purgert, Robert; Rhudy, Richard

2000-04-21

The highlights of this report are: (1) fly ash classified by less than 100 microns in size was mixed into a 300 lb melt of alloy 535 without the need of a magnesium additive; (2) a vibratory feeder fitted with a sieve was used as the means to minimize particle clustering while introducing fly ash into the aluminum alloy 535 melt; and (3) the industrial-size field test was successful in that sand mold castings and permanent mold castings of tensile bars, K mold bars, and ingots were made from aluminum alloy 535-fly ash mix. Use of aluminum alloy 535 containingmore » 7% magnesium precluded the need to introduce additional magnesium into the melt. The third round of sand mold castings as well as permanent mold castings produced components and ingots of alloy 535 instead of alloy 356. The ingots will be remelted and cast into parts to assess the improvement of flyash distribution which occurs through reheating and the solidification wetting process. Microstructure analysis continues on sand and permanent mold castings to study particle distribution in the components. A prototype sand cast intake manifold casting was found to be pressure tight which is a major performance requirement for this part. Another heat of pressure die cast brackets of A380-classified fly ash will be made to examine their strength and fly ash distribution. Ingots of A356-fly ash have been made at Eck for remelting at Thompson Aluminum for squeeze casting into motor mounts.« less

Serious infectious complications related to extremity cast/splint placement in children.

PubMed

Delasobera, B Elizabeth; Place, Rick; Howell, John; Davis, Jonathan E

2011-07-01

Extremity injuries necessitating splinting or casting are commonly seen in the emergency department (ED) setting. Subsequently, it is not uncommon for patients to present to the ED with complaints related to an extremity cast or splint. To present a literature-based approach to the identification and initial management of patients with possible infectious cast/splint complications in the ED setting. We present two cases of serious infectious complications arising from extremity cast/splint placement seen in a single pediatric ED: a case of toxic shock syndrome in an 8-year-old child, and a case of necrotizing fasciitis resulting in upper extremity amputation in a 3-year-old child. A wide spectrum of potential extremity cast/splint infectious complications may be seen, which include limb- or life-threatening infections such as toxic shock syndrome and necrotizing fasciitis. Simply considering these diagnoses, and removing the cast or splint to carefully inspect the affected extremity, are potential keys to early identification and optimal outcome of cast/splint complications. It is also prudent to maintain particular vigilance when treating a patient with a water-exposed cast, which may lead to moist padding, skin breakdown, and potential infection. In patients with suspected serious infections, aggressive fluid management and antibiotic therapy should be initiated and appropriate surgical consultation obtained without delay. Copyright © 2011 Elsevier Inc. All rights reserved.

[Cohort study of the incidence of heel pressure sores in patients with leg casts at the Rizzoli Orthopedic Hospital and of the associated risk factors].

PubMed

Forni, Cristiana; Zoli, Marina; Loro, Loretta; Tremosini, Morena; Mini, Sandra; Pirini, Valter; Turrini, Roberta; Durante, Stefano; Nicolini, Annamaria; Riccioni, Francesca; Girolami, Roberto

2009-01-01

Pressure sores, especially at the heel, are a side effect of the cast. To assess the incidence of late skin complications (heel pressure sores) of a cast and determine risk factors. All consecutive patients treated with a leg cast over a 16 months observation time were recruited. Risk factors were identified by the nurse that placed the cast and skin lesions classified with the NPUAP scale when the cast was removed. In the 216 enrolled patients 17.6% (38) developed a pressure sore: 16/124 in orthopedic wards; 22/92 in oncology wards. The multivariate analysis identified the following risk factors: administration of cytotoxic drugs (p = 0.033; OR = 2.61; having a cancer did not increase the risk); skin redness before cast application (p = 0.001; OR = 4.44) and having reported symptoms after the application (p = 0.000; OR = 7.86). Pressure sores were mainly stage 1 and only 6/216 (2.4%) > or = stage II. The type of plaster cast, the material, the number of days it was worn and having had a surgery are not significant risk factors. Pressure sores related to leg plaster casts are a frequent complication in at risk sub-groups. The acknowledgement and identification of specific risk factors may allow to identify and evaluate preventive interventions to improve the care of these patients.

Accuracy of impressions with different impression materials in angulated implants.

PubMed

Reddy, S; Prasad, K; Vakil, H; Jain, A; Chowdhary, R

2013-01-01

To evaluate the dimensional accuracy of the resultant (duplicative) casts made from two different impression materials (polyvinyl siloxane and polyether) in parallel and angulated implants. Three definitive master casts (control groups) were fabricated in dental stone with three implants, placed at equi-distance. In first group (control), all three implants were placed parallel to each other and perpendicular to the plane of the cast. In the second and third group (control), all three implants were placed at 10° and 15 o angulation respectively to the long axis of the cast, tilting towards the centre. Impressions were made with polyvinyl siloxane and polyether impression materials in a special tray, using a open tray impression technique from the master casts. These impressions were poured to obtain test casts. Three reference distances were evaluated on each test cast by using a profile projector and compared with control groups to determine the effect of combined interaction of implant angulation and impression materials on the accuracy of implant resultant cast. Statistical analysis revealed no significant difference in dimensional accuracy of the resultant casts made from two different impression materials (polyvinyl siloxane and polyether) by closed tray impression technique in parallel and angulated implants. On the basis of the results of this study, the use of both the impression materials i.e., polyether and polyvinyl siloxane impression is recommended for impression making in parallel as well as angulated implants.

Compound cast product and method for producing a compound cast product

DOEpatents

Meyer, Thomas N.; Viswanathan, Srinath

2002-09-17

A compound cast product is formed in a casting mold (14) having a mold cavity (16) sized and shaped to form the cast product. A plurality of injectors (24) is supported from a bottom side (26) of the casting mold (14). The injectors (24) are in fluid communication with the mold cavity (16) through the bottom side (26) of the casting mold (14). A molten material holder furnace (12) is located beneath the casting mold (14). The holder furnace (12) defines molten material receiving chambers (36) configured to separately contain supplies of two different molten materials (37, 38). The holder furnace (12) is positioned such that the injectors (24) extend downward into the receiving chamber (36). The receiving chamber (36) is separated into at least two different flow circuits (51, 52). A first molten material (37) is received in a first flow circuit (51), and a second molten material (38) is received into a second flow circuit (52). The first and second molten materials (37, 38) are injected into the mold cavity (16) by the injectors (24) acting against the force of gravity. The injectors (24) are positioned such that the first and second molten materials (37, 38) are injected into different areas of the mold cavity (16). The molten materials (37, 38) are allowed to solidify and the resulting compound cast product is removed from the mold cavity (16).

40 CFR 63.5810 - What are my options for meeting the standards for open molding and centrifugal casting operations...

Code of Federal Regulations, 2011 CFR

2011-07-01

... standards for open molding and centrifugal casting operations at new and existing sources? 63.5810 Section... § 63.5810 What are my options for meeting the standards for open molding and centrifugal casting... (d) of this section to meet the standards for open molding or centrifugal casting operations in Table...