Intraoperative Optical Coherence Tomography-Assisted 27-Gauge Vitrectomy in Eyes with Vitreoretinal Diseases

Directory of Open Access Journals (Sweden)

Hiroshi Kunikata

2015-07-01

Full Text Available Objective: To report intraoperative optical coherence tomography (iOCT-assisted 27-gauge microincision vitrectomy surgery (MIVS in eyes with vitreoretinal disease. Methods: A retrospective, interventional case series performed at a single center, including 6 eyes with retinal disease that underwent iOCT-assisted 27-gauge MIVS. Results: The advantages of iOCT were most notable when it was used to evaluate, in real time, different macular areas: the pre-macula, in vitreomacular traction or epiretinal membrane; the intra-macula, in macular edema or macular hole; and the sub-macula, in macular detachment. Real-time imaging and the minimization of shadows cast on the underlying tissues by the 27-gauge instrumentation made it possible to quickly select the best procedure at each critical juncture of the surgery. No patients experienced any complications. Conclusion: Real-time iOCT imaging during 27-gauge MIVS provided excellent intraoperative visualization of retinal tissues without causing significant obstructions to the surgeon. The positive feedback from the system allowed the surgeon to better judge the necessity of additional surgical procedures.

Casting Technology.

Science.gov (United States)

Wright, Michael D.; And Others

1992-01-01

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

Solidification and casting

CERN Document Server

Cantor, Brian

2002-01-01

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

Inoculation Effects of Cast Iron

Directory of Open Access Journals (Sweden)

E. Fraś

2012-12-01

Full Text Available The paper presents a solidification sequence of graphite eutectic cells of A and D types, as well as globular and cementite eutectics. The morphology of eutectic cells in cast iron, the equations for their growth and the distances between the graphite precipitations in A and D eutectic types were analyzed. It is observed a critical eutectic growth rate at which one type of eutectic transformed into another. A mathematical formula was derived that combined the maximum degree of undercooling, the cooling rate of cast iron, eutectic cell count and the eutectic growth rate. One type of eutectic structure turned smoothly into the other at a particular transition rate, transformation temperature and transformational eutectic cell count. Inoculation of cast iron increased the number of eutectic cells with flake graphite and the graphite nodule count in ductile iron, while reducing the undercooling. An increase in intensity of inoculation caused a smooth transition from a cementite eutectic structure to a mixture of cementite and D type eutectic structure, then to a mixture of D and A types of eutectics up to the presence of only the A type of eutectic structure. Moreover, the mechanism of inoculation of cast iron was studied.

Bainite obtaining in cast iron with carbides castings

Directory of Open Access Journals (Sweden)

S. Pietrowski

2010-01-01

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

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

Science.gov (United States)

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

2013-01-01

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

Radiographic Co-60 in component of heavy equipment casting

International Nuclear Information System (INIS)

Djoli Soembogo, Harun Al Rasyid R dan Namad Sianta

2016-01-01

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

Melting and casting of FeAl-based cast alloy

Energy Technology Data Exchange (ETDEWEB)

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

1998-11-01

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

Numerical simulation and optimization of Al alloy cylinder body by low pressure die casting

Directory of Open Access Journals (Sweden)

Mi Guofa

2008-05-01

Full Text Available Shrinkage defects can be formed easily at Critical location during low pressure die casting (LPDC of aluminum alloy cylinder body. It has harmful effect on the products. Mold fi lling and solidifi cation process of a cylinder body was simulated by using of Z-CAST software. The casting method was improved based on the simulation results. In order to create effective feeding passage, the structure of casting was modifi ed by changing the location of strengthening ribs at the bottom, without causing any adverse effect on the part’s performance. Inserting copper billet at suitable location of the die is a valid way to create suitable solidifi cation sequence that is benefi cial to the feeding. Using these methods, the shrinkage defect was completely eliminated at the critical location.

Characterization of fold defects in AZ91D and AE42 magnesium alloy permanent mold castings

International Nuclear Information System (INIS)

Bichler, L.; Ravindran, C.

2010-01-01

Casting premium-quality magnesium alloy components for aerospace and automotive applications poses unique challenges. Magnesium alloys are known to freeze rapidly prior to filling a casting cavity, resulting in misruns and cold shuts. In addition, melt oxidation, solute segregation and turbulent metal flow during casting contribute to the formation of fold defects. In this research, formation of fold defects in AZ91D and AE42 magnesium alloys cast via the permanent mold casting process was investigated. Computer simulations of the casting process predicted the development of a turbulent metal flow in a critical casting region with abrupt geometrical transitions. SEM and light optical microscopy examinations revealed the presence of folds in this region for both alloys. However, each alloy exhibited a unique mechanism responsible for fold formation. In the AZ91D alloy, melt oxidation and velocity gradients in the critical casting region prevented fusion of merging metal front streams. In the AE42 alloy, limited solubility of rare-earth intermetallic compounds in the α-Mg phase resulted in segregation of Al 2 RE particles at the leading edge of a metal front and created microstructural inhomogeneity across the fold.

Use of freeze-casting in advanced burner reactor fuel design

Energy Technology Data Exchange (ETDEWEB)

Lang, A. L.; Yablinsky, C. A.; Allen, T. R. [Dept. of Engineering Physics, Univ. of Wisconsin Madison, 1500 Engineering Drive, Madison, WI 53711 (United States); Burger, J.; Hunger, P. M.; Wegst, U. G. K. [Thayer School of Engineering, Dartmouth College, 8000 Cummings Hall, Hanover, NH 03755 (United States)

2012-07-01

This paper will detail the modeling of a fast reactor with fuel pins created using a freeze-casting process. Freeze-casting is a method of creating an inert scaffold within a fuel pin. The scaffold is created using a directional solidification process and results in open porosity for emplacement of fuel, with pores ranging in size from 300 microns to 500 microns in diameter. These pores allow multiple fuel types and enrichments to be loaded into one fuel pin. Also, each pore could be filled with varying amounts of fuel to allow for the specific volume of fission gases created by that fuel type. Currently fast reactors, including advanced burner reactors (ABR's), are not economically feasible due to the high cost of operating the reactors and of reprocessing the fuel. However, if the fuel could be very precisely placed, such as within a freeze-cast scaffold, this could increase fuel performance and result in a valid design with a much lower cost per megawatt. In addition to competitive costs, freeze-cast fuel would also allow for selective breeding or burning of actinides within specific locations in fast reactors. For example, fast flux peak locations could be utilized on a minute scale to target specific actinides for transmutation. Freeze-cast fuel is extremely flexible and has great potential in a variety of applications. This paper performs initial modeling of freeze-cast fuel, with the generic fast reactor parameters for this model based on EBR-II. The core has an assumed power of 62.5 MWt. The neutronics code used was Monte Carlo N-Particle (MCNP5) transport code. Uniform pore sizes were used in increments of 100 microns. Two different freeze-cast scaffold materials were used: ceramic (MgO-ZrO{sub 2}) and steel (SS316L). Separate models were needed for each material because the freeze-cast ceramic and metal scaffolds have different structural characteristics and overall porosities. Basic criticality results were compiled for the various models

Deducing material quality in cast and hot-forged steels by new bending test

Science.gov (United States)

Valberg, Henry; Langøy, Morten; Nedreberg, Mette; Helvig, Torgeir

2017-10-01

A special bend test has been developed and applied for the purpose of characterization and comparison of the material ductility in crankpin steel discs manufactured by casting, or casting subsequently followed by hot open-die forging (ODF) or closed-die forging (CDF). The bending test specimen consists of a small rectangular plate of material with a round hole cut out in the middle. The "eye-shape" specimens were cut out from various positions either near to the surface of, or from the interior of the discs. The test method revealed differences in ductility for the investigated materials, and for different depth positions inside the discs. The roughening of the specimen surface on the top-side of the specimen bend also varied dependent on the processing method for the material. Current results show that this test method is useful for evaluation of material quality in differently processed material. Experimental bend test results are presented for differently processed variants of the same material, i.e., crankpin discs either made by solely casting or casting subsequently followed by hot working either by ODF or CDF.

Tape casting and partial melting of Bi-2212 thick films

Energy Technology Data Exchange (ETDEWEB)

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

1994-12-31

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

Eyes Wide Open

Directory of Open Access Journals (Sweden)

Zoi Manesi

2016-04-01

Full Text Available Research from evolutionary psychology suggests that the mere presence of eye images can promote prosocial behavior. However, the “eye images effect” is a source of considerable debate, and findings across studies have yielded somewhat inconsistent support. We suggest that one critical factor may be whether the eyes really need to be watching to effectively enhance prosocial behavior. In three experiments, we investigated the impact of eye images on prosocial behavior, assessed in a laboratory setting. Participants were randomly assigned to view an image of watching eyes (eyes with direct gaze, an image of nonwatching eyes (i.e., eyes closed for Study 1 and averted eyes for Studies 2 and 3, or an image of flowers (control condition. Upon exposure to the stimuli, participants decided whether or not to help another participant by completing a dull cognitive task. Three independent studies produced somewhat mixed results. However, combined analysis of all three studies, with a total of 612 participants, showed that the watching component of the eyes is important for decision-making in this context. Images of watching eyes led to significantly greater inclination to offer help as compared to images of nonwatching eyes (i.e., eyes closed and averted eyes or images of flowers. These findings suggest that eyes gazing at an individual, rather than any proxy to social presence (e.g., just the eyes, serve as a reminder of reputation. Taken together, we conclude that it is “eyes that pay attention” that can lift the veil of anonymity and potentially facilitate prosocial behavior.

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

Science.gov (United States)

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

2017-01-01

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

Investment casting: parameters, application and recent development

International Nuclear Information System (INIS)

Zaid, A.I.O.

2007-01-01

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

Clinical comparison of the (polymacon) spin-cast hydrogel contact lens to the (polymacon) lathe-cut hydrogel lenses.

Science.gov (United States)

Hill, J F

1980-08-01

The purpose of this study was to compare the clinical acceptability of polymacon spin-cast to polymacon lathe-cut hydrophilic contact lenses. Ten patients successfully wearing polymacon spin-cast lenses were studied. Each patient had one eye refitted with polymacon lathe-cut lenses. Comparison of the two types of lenses was then made. Objective evaluation included centration, movement, visual acuity, and over-refraction. Subjective criteria were based on patient comfort and stability and quality of vision. Results indicate that lathe-cut lenses can be just as clinically satisfactory as the spincast ones.

Data Package for Secondary Waste Form Down-Selection-Cast Stone

International Nuclear Information System (INIS)

Serne, R. Jeffrey; Westsik, Joseph H.

2011-01-01

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

Data Package for Secondary Waste Form Down-Selection—Cast Stone

Energy Technology Data Exchange (ETDEWEB)

Serne, R. Jeffrey; Westsik, Joseph H.

2011-09-05

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

Control of cast iron and casts manufacturing by Inmold method

Directory of Open Access Journals (Sweden)

S. Pietrowski

2009-07-01

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

The casting of western sculpture during the XIXth century: sand casting versus lost wax casting

NARCIS (Netherlands)

Beentjes, T.P.C.

2014-01-01

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

Effects of heat pipe cooling on permanent mold castings of aluminum alloys

International Nuclear Information System (INIS)

Zhang, C.; Mucciardi, F.; Gruzleski, J.E.

2002-01-01

The temperature distribution within molds is a critical parameter in determining the ultimate casting quality in permanent mold casting processes, so there is a considerable incentive to develop a more effective method of mold cooling. Based on this consideration, a novel, effective and controllable heat pipe has been successfully developed and used as a new method of permanent mold cooling. Symmetric step casting of A356 alloy have been produced in an experimental permanent mold made of H13 tool steel, which is cooled by such heat pipes. The experimental results show that heat pipes can provide extremely high cooling rates in permanent mold castings of aluminum. The dendrite arm spacing of A356 alloy is refined considerably, and porosity and shrinkage of the castings are redistributed by the heat pipe cooling. Moreover, the heat pipe can be used to determine the time when the air gap forms at the interface between the mold and the casting. The effect of heat pipe cooling on solidification time of castings of A356 alloy with different coating types is also discussed in this paper. (author)

Rapidly cast crystalline thin sheet materials

International Nuclear Information System (INIS)

Warlimont, H.; Emmerich, K.

1986-01-01

The current state and progress of casting thin sheet and ribbons directly from the melt are reviewed. First, the solidification phenomena pertinent to the process are outlined. Subsequently, Fe-Si,l Fe-Si-Al, Fe-Nd-B, Ag-Cu-Ti, alloy steels, Ni superalloys and Si are treated as examples. Finally, the information available on process development is critically assessed

The Optical Design of the Human Eye: a Critical Review

Directory of Open Access Journals (Sweden)

Rafael Navarro

2009-01-01

Full Text Available Cornea, lens and eye models are analyzed and compared to experimental findings to assess properties and eventually unveil optical design principles involved in the structure and function of the optical system of the eye. Models and data often show good match but also some paradoxes. The optical design seems to correspond to a wide angle lens. Compared to conventional optical systems, the eye presents a poor optical quality on axis, but a relatively good quality off-axis, thus yielding higher homogeneity for a wide visual field. This seems the result of an intriguing combination of the symmetry design principle with a total lack of rotational symmetry, decentrations and misalignments of the optical surfaces.

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

Science.gov (United States)

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

2018-03-01

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

Neutron radiography inspection of investment castings

International Nuclear Information System (INIS)

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

2004-01-01

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

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

Science.gov (United States)

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

2016-02-01

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

Plastic-casting intrinsic-surface unique identifier (tag)

International Nuclear Information System (INIS)

Palm, R.G.; De Volpi, A.

1995-04-01

This report describes the development of an authenticated intrinsic-surf ace tagging method for unique- identification of controlled items. Although developed for control of items limited by an arms control treaty, this method has other potential applications to keep track of critical or high-value items. Each tag (unique-identifier) consists of the intrinsic, microscopic surface topography of a small designated area on a controlled item. It is implemented by making a baseline plastic casting of the designated tag area and usually placing a cover (for example, a bar-code label) over this area to protect the surface from environmental alteration. The plastic casting is returned to a laboratory and prepared for high-resolution scanning electron microscope imaging. Several images are digitized and stored for use as a standard for authentication of castings taken during future inspections. Authentication is determined by numerically comparing digital images. Commercially available hardware and software are used for this tag. Tag parameters are optimized, so unique casting images are obtained from original surfaces, and images obtained from attempted duplicate surfaces are detected. This optimization uses the modulation transfer function, a first principle of image analysis, to determine the parameters. Surface duplication experiments confirmed the optimization

Travelling Through Caste

OpenAIRE

Kumar, Raj

2016-01-01

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

Microstructural causes of negative creep in cast superalloys

International Nuclear Information System (INIS)

Frank, G.

1990-01-01

The dissertation examines by means of microstructural investigations and modelling calculations two types of superalloys: the nickel-base cast alloy IN 738 LC (γ'-hardened, containing MC and M 23 C 6 carbides), and the cobalt-base cast alloy FSX 414 (containing M 23 C 6 carbides, solid solution-hardened). The task was to determine the causes of microstructural volume contraction, in order to improve and facilitate explanation and extrapolation of the materials' long-term behaviour at high temperatures, and to derive if possible information on appropriate measures preventing negative creep, which may lead to critical damage of bolted joints, for instance. (orig./MM) [de

Caste and power

DEFF Research Database (Denmark)

Roy, Dayabati

2011-01-01

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

Technological Aspects of Low-Alloyed Cast Steel Massive Casting Manufacturing

Directory of Open Access Journals (Sweden)

Szajnara J.

2013-12-01

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

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

Science.gov (United States)

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

2017-12-01

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

Irradiation response of delta ferrite in as-cast and thermally aged cast stainless steel

Energy Technology Data Exchange (ETDEWEB)

Li, Zhangbo; Lo, Wei-Yang [Department of Materials Science and Engineering, Nuclear Engineering Program, University of Florida, Gainesville, FL 32611 (United States); Chen, Yiren [Nuclear Engineering Division, Argonne National Laboratory, Lemont, IL 60439 (United States); Pakarinen, Janne [Belgian Nuclear Research Center (SCK-CEN), Boeretang 200, B-2400 Mol (Belgium); Wu, Yaqiao [Department of Materials Science and Engineering, Boise State University, Boise, ID 83715 (United States); Center for Advanced Energy Studies, Idaho Falls, ID 83401 (United States); Allen, Todd [Engineering Physics Department, University of Wisconsin, Madison, WI 53706 (United States); Idaho National Laboratory, Idaho Falls, ID 83415 (United States); Yang, Yong, E-mail: yongyang@ufl.edu [Department of Materials Science and Engineering, Nuclear Engineering Program, University of Florida, Gainesville, FL 32611 (United States)

2015-11-15

To enable the life extension of Light Water Reactors (LWRs) beyond 60 years, it is critical to gain adequate knowledge for making conclusive predictions to assure the integrity of duplex stainless steel reactor components, e.g. primary pressure boundary and reactor vessel internal. Microstructural changes in the ferrite of thermally aged, neutron irradiated only, and neutron irradiated after being thermally aged cast austenitic stainless steels (CASS) were investigated using atom probe tomography. The thermal aging was performed at 400 °C for 10,000 h and the irradiation was conducted in the Halden reactor at ∼315 °C to 0.08 dpa (5.6 × 10{sup 19} n/cm{sup 2}, E > 1 MeV). Low dose neutron irradiation at a dose rate of 5 × 10{sup −9} dpa/s was found to induce spinodal decomposition in the ferrite of as-cast microstructure, and further to enhance the spinodal decomposition in the thermally aged cast alloys. Regarding the G-phase precipitates, the neutron irradiation dramatically increases the precipitate size, and alters the composition of the precipitates with increased, Mn, Ni, Si and Mo and reduced Fe and Cr contents. The results have shown that low dose neutron irradiation can further accelerate the degradation of ferrite in a duplex stainless steel at the LWR relevant condition.

Irradiation response of delta ferrite in as-cast and thermally aged cast stainless steel

International Nuclear Information System (INIS)

Li, Zhangbo; Lo, Wei-Yang; Chen, Yiren; Pakarinen, Janne; Wu, Yaqiao; Allen, Todd; Yang, Yong

2015-01-01

To enable the life extension of Light Water Reactors (LWRs) beyond 60 years, it is critical to gain adequate knowledge for making conclusive predictions to assure the integrity of duplex stainless steel reactor components, e.g. primary pressure boundary and reactor vessel internal. Microstructural changes in the ferrite of thermally aged, neutron irradiated only, and neutron irradiated after being thermally aged cast austenitic stainless steels (CASS) were investigated using atom probe tomography. The thermal aging was performed at 400 °C for 10,000 h and the irradiation was conducted in the Halden reactor at ∼315 °C to 0.08 dpa (5.6 × 10"1"9 n/cm"2, E > 1 MeV). Low dose neutron irradiation at a dose rate of 5 × 10"−"9 dpa/s was found to induce spinodal decomposition in the ferrite of as-cast microstructure, and further to enhance the spinodal decomposition in the thermally aged cast alloys. Regarding the G-phase precipitates, the neutron irradiation dramatically increases the precipitate size, and alters the composition of the precipitates with increased, Mn, Ni, Si and Mo and reduced Fe and Cr contents. The results have shown that low dose neutron irradiation can further accelerate the degradation of ferrite in a duplex stainless steel at the LWR relevant condition.

A study on the effects of artifacts on fatigue limit of ductile cast iron with ferritic structure

International Nuclear Information System (INIS)

Kim, Jin Hak; Kim, Min Gun

2000-01-01

In this study, fatigue tests were performed to examine the effects of micro drill hole on fatigue limit of as cast and Austempered Ductile cast Iron (ADI) using the rotary bending fatigue tester. As results, micro drill holes (diameter≤0.4mm) did not influence the fatigue limit of ADI, compared to annealed ductile cast iron; the critical defect size of crack initiation, in ADI was larger than as cast. If the √areas of micro drill hole and graphite nodule in ADI are comparable, crack initiates at the graphite nodule. When the ruggedness develops through austempering treatment process, microstructure on crack initiation at micro drill hole is tougher than that of as cast ductile cast iron

Experimental Tape Casting of Adjacently Graded Materials for Magnetic Refrigeration

DEFF Research Database (Denmark)

Bulatova, Regina

encompass modification of the entire tape caster into a multi chamber unit, establishment of the optimal operating parameters such as casting gap, speed, and slurry level in the tape caster reservoir, and elucidation of the impact of chamber partition design on the quality of the final tape. The second...... of the side-by-side tape casting technique: recognising critical parameters which affect the quality of a graded tape, shape and position of the interface area. Studied parameters can be divided into two categories: operational parameters and slurry formulation optimisation. The operational parameters...

The Effect of Shell Thickness, Insulation and Casting Temperature on Defects Formation During Investment Casting of Ni-base Turbine Blades

Directory of Open Access Journals (Sweden)

Raza M.

2015-12-01

Full Text Available Turbine blades have complex geometries with free form surface. Blades have different thickness at the trailing and leading edges as well as sharp bends at the chord-tip shroud junction and sharp fins at the tip shroud. In investment casting of blades, shrinkage at the tip-shroud and cord junction is a common casting problem. Because of high temperature applications, grain structure is also critical in these castings in order to avoid creep. The aim of this work is to evaluate the effect of different process parameters, such as, shell thickness, insulation and casting temperature on shrinkage porosity and grain size. The test geometry used in this study was a thin-walled air-foil structure which is representative of a typical hot-gas-path rotating turbine component. It was observed that, in thin sections, increased shell thickness helps to increase the feeding distance and thus avoid interdendritic shrinkage. It was also observed that grain size is not significantly affected by shell thickness in thin sections. Slower cooling rate due to the added insulation and steeper thermal gradient at metal mold interface induced by the thicker shell not only helps to avoid shrinkage porosity but also increases fill-ability in thinner sections.

Rotation of lathe-cut hydrogel lenses on the eye.

Science.gov (United States)

Harris, M G; Harris, K L; Ruddell, D

1976-01-01

The rotation lathe-cut HydroCurveTM gel contact lens was measured on six eyes to evaluate the parameters that influence lens rotation and to determine if this lens could be used to correct astigmatism. Of the 72 observations made, 73.6% showed some lens rotation, and 33.4% of the sample rotated more than 5 degrees per 10 blinks. Of the observations in which rotation was noted, 88.7% were encyclorotation. These results are similar to those found for spin-cast hydrogel lenses. None of the lens parameters evaluated seemed to be related to lens rotation, whereas the eye parameters studied were. Lenses were more likely to rotate on eyes with smaller corneal diameters, smaller palpebral apertures, and corneal curvatures steeper than 4 3.00 DK (X2, N =72, p less than 0.05). Our findings indicate that some method of lens stabilization will be needed before lathe-cut hydrogel lenses can be used to effectively correct astigmatism.

Effect of cast steel production metallurgy on the emergence of casting defects

Directory of Open Access Journals (Sweden)

L. Čamek

2016-10-01

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

SPRAY CASTING

OpenAIRE

SALAMCI, Elmas

2010-01-01

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

Die casting copper motor rotors: mold materials and processing for cost-effective manufacturing

Energy Technology Data Exchange (ETDEWEB)

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

2000-07-01

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

Eye tracking and the translation process

DEFF Research Database (Denmark)

Hvelplund, Kristian Tangsgaard

2014-01-01

Eye tracking has become increasingly popular as a quantitative research method in translation research. This paper discusses some of the major methodological issues involved in the use of eye tracking in translation research. It focuses specifically on challenges in the analysis and interpretation...... of eye-tracking data as reflections of cognitive processes during translation. Four types of methodological issues are discussed in the paper. The first part discusses the preparatory steps that precede the actual recording of eye-tracking data. The second part examines critically the general assumptions...... linking eye movements to cognitive processing in the context of translation research. The third part of the paper discusses two popular eye-tracking measures often used in translation research, fixations and pupil size, while the fourth part proposes a method to evaluate the quality of eye-tracking data....

TECHNOLOGICAL PARAMETERS OF SLUGS CASTING OF GREY CAST IRON BY FROSTING

Directory of Open Access Journals (Sweden)

E. I. Marukovich

2009-01-01

Full Text Available The relation of geometrical parametres of casting with technological ones is shown. The monogram for definition of basic technological parametres of obtaining of castings by the method of continuously-cyclic iterative casting by freezing-up is presented.

Colour Metallography of Cast Iron - Chapter 3: Spheroidal Graphite Cast Iron (Ⅳ

Directory of Open Access Journals (Sweden)

Zhou Jiyang

2010-11-01

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

Colour Metallography of Cast Iron - Chapter 3: Spheroidal Graphite Cast Iron (Ⅰ

Directory of Open Access Journals (Sweden)

Zhou Jiyang

2010-02-01

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

Colour Metallography of Cast Iron - Chapter 4: Vermicular Graphite Cast Iron (Ⅱ

Directory of Open Access Journals (Sweden)

Zhou Jiyang

2011-05-01

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

Effects of process variables on the properties of YBa2Cu3O(7-x) ceramics formed by investment casting

Science.gov (United States)

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

1993-01-01

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

The deformation of wax patterns and castings in investment casting technology

Directory of Open Access Journals (Sweden)

A. Herman

2012-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-10-04

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

Anodization of cast aluminium alloys produced by different casting methods

Directory of Open Access Journals (Sweden)

K. Labisz

2008-08-01

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

Cast iron - a predictable material

Directory of Open Access Journals (Sweden)

Jorg C. Sturm

2011-02-01

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

Dimensional control of die castings

Science.gov (United States)

Karve, Aniruddha Ajit

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

Method and apparatus for improved melt flow during continuous strip casting

Science.gov (United States)

Follstaedt, Donald W.; King, Edward L.; Schneider, Ken C.

1991-11-12

The continuous casting of metal strip using the melt overflow process is improved by controlling the weir conditions in the nozzle to provide a more uniform flow of molten metal across the width of the nozzle and reducing the tendency for freezing of metal along the interface with refractory surfaces. A weir design having a sloped rear wall and tapered sidewalls and critical gap controls beneath the weir has resulted in the drastic reduction in edge tearing and a significant improvement in strip uniformity. The floor of the container vessel is preferably sloped and the gap between the nozzle and the rotating substrate is critically controlled. The resulting flow patterns observed with the improved casting process have reduced thermal gradients in the bath, contained surface slag and eliminated undesirable solidification near the discharge area by increasing the flow rates at those points.

Social-scientific criticism: Perspective, process and payoff. Evil eye ...

African Journals Online (AJOL)

Test

2010-05-19

May 19, 2010 ... Evil eye accusation at Galatia as illustration of the method .... the Jesus faction and the rival Pharisees or the Pauline Christ movement and the group around ..... used to protect a cucumber field from the withering glance.

Compound cast product and method for producing a compound cast product

Science.gov (United States)

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).

Multi-layers castings

Directory of Open Access Journals (Sweden)

J. Szajnar

2010-01-01

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

Rheologic behaviors of A356 aluminum alloy billet produced by semisolid continuous casting process

Directory of Open Access Journals (Sweden)

Shuming XING

2004-08-01

Full Text Available The experiments for rheologic behaviors of semisolid continous casting billets of A356 alloy in semisolid state has been carried out with a multifunctional rheometer. The results show that the deformation rate increases with loading time, the maximum strain reaches 120% (which is one time larger than that of traditional casting billet and the strain can be rapidly eliminated to 10% after unloading. Moreover, there is a critic stress for billet deformation even in semisolid state, which is named as critic shear stress. This stress increases with the decreasing of heating time. The rheologic behaviors can be expressed by five elements mechanical model and can be modified with the increasing of heating time.

Section thickness-dependent tensile properties of squeeze cast magnesium alloy AM60

Directory of Open Access Journals (Sweden)

Xuezhi Zhang

2012-05-01

Full Text Available The development of alternative casting processes is essential for the high demand of light weight magnesium components to be used in the automotive industry, which often contain different section thicknesses. Squeeze casting with its inherent advantages has been approved for the capability of minimizing the gas porosity in magnesium alloys. For advanced engineering design of light magnesium automotive applications, it is critical to understand the effect of section thickness on mechanical properties of squeeze cast magnesium alloys. In this study, magnesium alloy AM60 with different section thicknesses of 6, 10 and 20 mm squeeze cast under an applied pressure of 30 MPa was investigated. The prepared squeeze cast AM60 specimens were tensile tested at room termperature. The results indicate that the mechanical properties including yield strength (YS, ultimate tensile strength (UTS and elongation (A decrease with an increase in section thickness of squeeze cast AM60. The microstructure analysis shows that the improvement in the tensile behavior of squeeze cast AM60 is primarily attributed to the low-gas porosity level and fine grain strucuture which result from the variation of cooling rate of different section thickness. The numerical simulation (Magmasoft? was employed to determine the solidification rates of each step, and the simulated results show that the solidification rate of the alloy decreases with an increase in the section thickness. The computed solidification rates support the experimental observation on grain structural development.

Accuracy of single-abutment digital cast obtained using intraoral and cast scanners.

Science.gov (United States)

Lee, Jae-Jun; Jeong, Ii-Do; Park, Jin-Young; Jeon, Jin-Hun; Kim, Ji-Hwan; Kim, Woong-Chul

2017-02-01

Scanners are frequently used in the fabrication of dental prostheses. However, the accuracy of these scanners is variable, and little information is available. The purpose of this in vitro study was to compare the accuracy of cast scanners with that of intraoral scanners by using different image impression techniques. A poly(methyl methacrylate) master model was fabricated to replicate a maxillary first molar single-abutment tooth model. The master model was scanned with an accurate engineering scanner to obtain a true value (n=1) and with 2 intraoral scanners (CEREC Bluecam and CEREC Omnicam; n=6 each). The cast scanner scanned the master model and duplicated the dental stone cast from the master model (n=6). The trueness and precision of the data were measured using a 3-dimensional analysis program. The Kruskal-Wallis test was used to compare the different sets of scanning data, followed by a post hoc Mann-Whitney U test with a significance level modified by Bonferroni correction (α/6=.0083). The type 1 error level (α) was set at .05. The trueness value (root mean square: mean ±standard deviation) was 17.5 ±1.8 μm for the Bluecam, 13.8 ±1.4 μm for the Omnicam, 17.4 ±1.7 μm for cast scanner 1, and 12.3 ±0.1 μm for cast scanner 2. The differences between the Bluecam and the cast scanner 1 and between the Omnicam and the cast scanner 2 were not statistically significant (P>.0083), but a statistically significant difference was found between all the other pairs (POmnicam, 9.2 ±1.2 μm for cast scanner 1, and 6.9 ±2.6 μm for cast scanner 2. The differences between Bluecam and Omnicam and between Omnicam and cast scanner 1 were not statistically significant (P>.0083), but there was a statistically significant difference between all the other pairs (POmnicam in video image impression had better trueness than a cast scanner but with a similar level of precision. Copyright © 2016 Editorial Council for the Journal of Prosthetic Dentistry. Published by

Identification of temperature changes dynamics in selected castings as a contribution to performance life improvement

Directory of Open Access Journals (Sweden)

A. Pytel

2010-07-01

Full Text Available Parameters describing boundary conditions and dynamics of temperature changes during casting cooling in foundry moulds and thesuccessive performance, especially as regards the massive cast elements, were discussed. Considering the specific nature of castingoperation, non-standard methods of examination of the isotherms of temperature fields on the casting surface were described to determinelocal overheating resulting from the technological process, chemical composition, properties of the currently applied insulation materials,casting defects and/or design. Identification of these parameters can be interpolated to laboratory conditions and to the validation of virtual models subject to computer simulation. The use in simulation of genetic algorithms combined with the results of measurements under real conditions enables more precise determination of the performance parameters, including critical states of stresses present in a structure. This should allow further optimisation of the massive castings design, considering the specific nature of a manufacturing process (alloy composition included, combined with performance parameters. Measures described here are expected to contribute to the reduced casting weight and longer time of operation.

Clean Metal Casting

Energy Technology Data Exchange (ETDEWEB)

Makhlouf M. Makhlouf; Diran Apelian

2002-02-05

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

Caste System

OpenAIRE

Hoff, Karla

2016-01-01

In standard economics, individuals are rational actors and economic forces undermine institutions that impose large inefficiencies. The persistence of the caste system is evidence of the need for psychologically more realistic models of decision-making in economics. The caste system divides South Asian society into hereditary groups whose lowest ranks are represented as innately polluted. ...

Gating Systems for Sizeable Castings from Al Alloys Cast into Ceramic Moulds

Directory of Open Access Journals (Sweden)

I. Stachovec

2012-04-01

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

Diffusion of C and Cr During Creation of Surface Layer on Cast Steel Casting

Directory of Open Access Journals (Sweden)

Szajnar J.

2014-10-01

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

U.S. Geological Survey's ShakeCast: A cloud-based future

Science.gov (United States)

Wald, David J.; Lin, Kuo-Wan; Turner, Loren; Bekiri, Nebi

2014-01-01

When an earthquake occurs, the U. S. Geological Survey (USGS) ShakeMap portrays the extent of potentially damaging shaking. In turn, the ShakeCast system, a freely-available, post-earthquake situational awareness application, automatically retrieves earthquake shaking data from ShakeMap, compares intensity measures against users’ facilities, sends notifications of potential damage to responsible parties, and generates facility damage assessment maps and other web-based products for emergency managers and responders. ShakeCast is particularly suitable for earthquake planning and response purposes by Departments of Transportation (DOTs), critical facility and lifeline utilities, large businesses, engineering and financial services, and loss and risk modelers. Recent important developments to the ShakeCast system and its user base are described. The newly-released Version 3 of the ShakeCast system encompasses advancements in seismology, earthquake engineering, and information technology applicable to the legacy ShakeCast installation (Version 2). In particular, this upgrade includes a full statistical fragility analysis framework for general assessment of structures as part of the near real-time system, direct access to additional earthquake-specific USGS products besides ShakeMap (PAGER, DYFI?, tectonic summary, etc.), significant improvements in the graphical user interface, including a console view for operations centers, and custom, user-defined hazard and loss modules. The release also introduces a new adaption option to port ShakeCast to the "cloud". Employing Amazon Web Services (AWS), users now have a low-cost alternative to local hosting, by fully offloading hardware, software, and communication obligations to the cloud. Other advantages of the "ShakeCast Cloud" strategy include (1) Reliability and robustness of offsite operations, (2) Scalability naturally accommodated, (3), Serviceability, problems reduced due to software and hardware uniformity, (4

Multiscale modeling for the prediction of casting defects in investment cast aluminum alloys

International Nuclear Information System (INIS)

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

2003-01-01

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

Childhood Eye Diseases and Conditions

Science.gov (United States)

... below. Early diagnosis and treatment are critical to maintaining your child’s eye health. Follow these screening recommendations ... About the Academy Jobs at the Academy Financial Relationships with Industry Medical Disclaimer Privacy Policy Terms of ...

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

Science.gov (United States)

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 cast using these two investment materials are both smooth enough to fulfill the demand of the titanium precision-casting for prosthodontic clinical use.

Examination and Elimination of Defects in Cone Casting Made of Ductile Cast Iron

Directory of Open Access Journals (Sweden)

Guzik E.

2013-12-01

Full Text Available In the scope of existing cooperation with the Foundry of Cast Iron ZM “WSK Rzeszów” Ltd. there was carried out research work of microstructure and mechanical properties in the walls of a cone casting made of ductile cast iron. The particular attention was being put to the search of the potential brittle phases which have deleterious effect on ductility and dynamic properties of highly strained use of the casting prone to the potential risk of cracks during the highly strained use.

Numerical microstructure prediction for an aluminium casting and its experimental validation

Directory of Open Access Journals (Sweden)

Unterreiter Guenter

2011-08-01

Full Text Available Virtual manufacturing based on through-process modelling becomes an evolving research area which aims at integrating diverse simulation tools to realize computer-aided design, analysis, prototyping and manufacturing. Numerical prediction of the as-cast microstructure is an initial and critical step in the whole through-process modelling chain for engineering components. A commercial software package with the capability of calculating important microstructure features for aluminium alloys is used to simulate a G-AlSi7MgCu0.5 laboratory casting. The simulated microstructure, namely grain size, secondary dendrite arm spacing and diverse phase fractions are verified experimentally. Correspondence and discrepancies are reported and discussed.

Colour Metallography of Cast Iron

Directory of Open Access Journals (Sweden)

Zhou Jiyang

2009-05-01

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

Rayleigh Number Criterion for Formation of A-Segregates in Steel Castings and Ingots

DEFF Research Database (Denmark)

Rad, M. Torabi; Kotas, Petr; Beckermann, C.

2013-01-01

A Rayleigh number-based criterion is developed for predicting the formation of A-segregates in steel castings and ingots. The criterion is calibrated using available experimental data for ingots involving 27 different steel compositions. The critical Rayleigh number above which A-segregates can b......, the primary reason for this over-prediction is persumed to be the presence of a central zone of equiaxed grains in the casting sections. A-segregates do not form when the grain structure is equiaxed. © The Minerals, Metals & Materials Society and ASM International 2013...

Casting characteristics of Al-Mg alloy 535 cast in permanent moulds

International Nuclear Information System (INIS)

Fasoyinu, F.A.; Thomson, J.; Cousineau, D.; Castles, T.; Sahoo, M.

2002-01-01

Aluminum alloy 535 could be used for automotive and marine applications because of its good corrosion resistance against mild alkaline and salt spray exposure. The majority of components from this alloy are usually produced by sand casting because it is prone to hot shortness and has poor fluidity when poured in permanent moulds. In an attempt to improve its castability in permanent moulds, casting characteristics such as casting fluidity and hot tear resistance have been studied. In addition, the effectiveness of titanium, boron, scandium, zirconium and a combination of selected elements from this group as grain refiners were evaluated. It s shown that alloy 535 exhibits good casting fluidity when poured with adequate metal superheat and that there is significant improvement in hot tear resistance following grain refinement. (author)

Applying RP-FDM Technology to Produce Prototype Castings Using the Investment Casting Method

Directory of Open Access Journals (Sweden)

M. Macků

2012-09-01

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

EFFECT OF ALLOYING ON TEMPERATURE OF TRANSFORMATION «PEARLITE – AUSTENITE» IN COMPLEX-ALLOYED WHITE CAST IRONS

Directory of Open Access Journals (Sweden)

T. V. Pastukhova

2014-11-01

Full Text Available Purpose. Pearlite is not accepted in the microstructure of wear resistant steels and cast irons. To prevent the pearlite by means of appropriate selection of mode of quenching requires the knowledge of the temperature of the critical points Ac1 and Ac3 for various steels and cast irons. Purpose of work is determine the effect of V (5-10% and Cr (up to 9% on the temperature range of the phase-structural transformation "pearlite®austenite in the complex-alloyed V-Cr-Mn-Ni white cast irons with spheroidal vanadium carbides. Methodology. Nine Mg-treated cast irons smelted in laboratory furnace were used for investigation. The metallographic and optical dilatometric analysis methods as well as energy-dispersive spectroscopy were used. Findings. It is shown that in irons studied the critical point Ac1 is in a temperature range from 710-780 °C (lower limit up to 730-850 °C (upper limit. The data on the concentrations of chromium and vanadium in a matrix of iron are presented, the regression equation describing the effect of vanadium and chromium on the temperature limits of the transformation «pearlite ® austenite» are obtained. Originality. It is shown that increase the chromium content leads to growth of lower and upper limits of the temperature interval of transformation "pearlite ® austenite"; vanadium increases only the upper limit of the range. It was found that the effect of chromium on the critical point Ac1 is attributed to its solubility in the metallic matrix (concentration of Cr in the austenite reaches 7%; vanadium, due to its slight dissolution in the matrix (vanadium content does not exceed 1.75%, affects the critical point indirectly by increasing of chromium concentration in the matrix due to enhanced carbon sequestration in VC carbides. Practical value. The temperature ranges of heating for quenching of V-Cr-Mn-Ni cast irons with spheroidal vanadium carbides, which provides the formation of austenitic-martensitic matrix without

Casting of microstructured shark skin surfaces and possible applications on aluminum casting parts

Directory of Open Access Journals (Sweden)

Todor Ivanov

2011-02-01

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

Aluminium Foam and Magnesium Compound Casting Produced by High-Pressure Die Casting

Directory of Open Access Journals (Sweden)

Iban Vicario

2016-01-01

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

A 1-D Analytical Model for the Thermally Induced Stresses in the Mould Surface During Die Casting

DEFF Research Database (Denmark)

Hattel, Jesper; Hansen, Preben

1994-01-01

This paper presents an anlytically based method for predicting the normal stresses in a die mold surface exposed to a thermal load. A example of application of the method is the high-pressure di casting process where the surface stresses in critical cases lead to cracks. Expressions for the normal...... stresses as afunction of the thermal and mechanical properties have been developed for a casting both without and with a coating. Finally, the resulting relationships are derived and evaluated, with particular emphasis on the effect of the heat transfer coefficient between the casting and the mold....

Applying RP-FDM Technology to Produce Prototype Castings Using the Investment Casting Method

Directory of Open Access Journals (Sweden)

Macků M.

2012-09-01

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

Casting AISI 316 steel by gel cast

International Nuclear Information System (INIS)

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

2004-01-01

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

Direct strip casting of steel - historical perspective and future direction

International Nuclear Information System (INIS)

Manohar, P.A.; Hunter, A.; Ferry, M.

2000-01-01

The commercialisation of direct strip casting (DSC) of steel represents the realisation of a dream cherished by engineers for over one hundred and fifty years. The story of the global competition for DSC of steel, that has ingredients of romanticism of chasing of a dream, adventure and intrigue, is being played out across continents over dozens of decades with an interplay of setbacks and successes. At this stage, DSC is set to make a profound impact on the steelmaking landscape. This paper reviews the important milestones in this compelling story, presents the current status and then gazes into the crystal ball in an attempt to predict which turn the story may take in the near future. The constraints and critical challenges for the successful commercialisation of DSC are highlighted. Recent results are discussed relating the production process to quality control and properties of unalloyed, low carbon strip-cast steels. future metallurgical challenges include a better understanding of solidification mechanism during high-speed casting and secondary processing variables affecting the final microstructure of austenitic grains

In vitro eye corrosion study of agrochemicals on isolated chicken eye.

Science.gov (United States)

Buda, I; Budai, P; Szabó, R; Lehel, J

2013-01-01

Agrochemicals must undergo numberless toxicological tests before marketing. The eye irritation test is part of this test packet. Nowadays, OECD 405 can be used to classify the irritation potential of substances, the base of the OECD 405 guideline is the Draize test, which is one of the most criticized in vivo methods because of the injuries of the test animals and subjective nature of the test in recording the results. Therefore, several in vitro tests have been developed to replace totally or partly the in vivo eye irritation testing. The isolated chicken eye test method (OECD 438), which was used, is one of these alternative methods. Five different agrochemicals were examined in the following way: All test compounds were applied in a single dose onto the cornea of isolated chicken eyes in order to potentially classify the test compounds as ocular corrosive and/or severe irritant. The damages caused by the test substances were assessed by the determination of corneal swelling, opacity, fluorescein retention and morphological effects. These parameters were evaluated pre-treatment and starting at approximately 30, 75, 120, 180, and 240 minutes after the post-treatment rinse. The endpoints evaluated were corneal opacity, swelling, fluorescein retention and morphological effects. All of the endpoints, with the exception of fluorescein retention (which was determined only at pre-treatment and 30 minutes after test substance exposure) were determined at each of the above time points. Positive and negative controls were used and they showed the expected results in each study. In these in vitro eye corrosives and severe irritants studies, using the Isolated Chicken Eye model with five different products, no ocular corrosion or severe irritation potential were observed. These results correspond to the available information about the tested agrochemicals, so these studies with isolated chicken eye are considered to be successful.

Symptomatic stent cast.

LENUS (Irish Health Repository)

Keohane, John

2012-02-03

Biliary stent occlusion is a major complication of endoscopic stent insertion and results in repeat procedures. Various theories as to the etiology have been proposed, the most frequently studied is the attachment of gram negative bacteria within the stent. Several studies have shown prolongation of stent patency with antibiotic prophylaxis. We report the case of stent occlusion from a cast of a previously inserted straight biliary stent; a "stent cast" in an 86-year-old woman with obstructive jaundice. This was retrieved with the lithotrypter and she made an uneventful recovery. This is the first reported case of a biliary stent cast.

Fracture Mechanisms in Steel Castings

Directory of Open Access Journals (Sweden)

Stradomski Z.

2013-09-01

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

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

Science.gov (United States)

Singh, Rupinder

2018-02-01

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

NUMERICAL MODELING OF HARDENING OF UNINTERRUPTEDLY-CASTED BRONZE CASTING

Directory of Open Access Journals (Sweden)

E. I. Marukovich

2009-01-01

Full Text Available The three-dimensional numerical model for calculation of thermal fields during solidification of continuously casted bronze casting is developed. Coefficients of heat transfer on borders of calculation areas on the basis of the solution of inverse heat transfer conduction problem are determined. The analysis of thermal fields, depending on loop variables of drawing and the sizes of not cooled zone of crystallizer is curried out.

Differentially expressed regulatory genes in honey bee caste development

Science.gov (United States)

Hepperle, C.; Hartfelder, K.

2001-03-01

In the honey bee, an eminently fertile queen with up to 200 ovarioles per ovary monopolizes colony level reproduction. In contrast, worker bees have only few ovarioles and are essentially sterile. This phenotype divergence is a result of caste-specifically modulated juvenile hormone and ecdysteroid titers in larval development. In this study we employed a differential-display reverse transcription (DDRT)-PCR protocol to detect ecdysteroid-regulated gene expression during a critical phase of caste development. We identified a Ftz-F1 homolog and a Cut-like transcript. Ftz-F1 could be a putative element of the metamorphic ecdysone response cascade of bees, whereas Cut-like proteins are described as transcription factors involved in maintaining cellular differentiation states. The downregulation of both factors can be interpreted as steps in the metamorphic degradation of ovarioles in worker-bee ovaries.

Casting thermal simulation

International Nuclear Information System (INIS)

Shamsuddin bin Sulaiman

1994-01-01

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

Clean Metal Casting; FINAL

International Nuclear Information System (INIS)

Makhlouf M. Makhlouf; Diran Apelian

2002-01-01

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

14 CFR 23.621 - Casting factors.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Casting factors. 23.621 Section 23.621... Casting factors. (a) General. The factors, tests, and inspections specified in paragraphs (b) through (d... structural castings except castings that are pressure tested as parts of hydraulic or other fluid systems and...

Hair casts

OpenAIRE

Sweta S Parmar; Kirti S Parmar; Bela J Shah

2014-01-01

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

Effect of inlet geometry on macrosegregation during the direct chill casting of 7050 alloy billets: experiments and computer modelling

International Nuclear Information System (INIS)

Zhang, L; Miroux, A; Subroto, T; Katgerman, L; Eskin, D G

2012-01-01

Controlling macrosegregation is one of the major challenges in direct-chill (DC) casting of aluminium alloys. In this paper, the effect of the inlet geometry (which influences the melt distribution) on macrosegregation during the DC casting of 7050 alloy billets was studied experimentally and by using 2D computer modelling. The ALSIM model was used to determine the temperature and flow patterns during DC casting. The results from the computer simulations show that the sump profiles and flow patterns in the billet are strongly influenced by the melt flow distribution determined by the inlet geometry. These observations were correlated to the actual macrosegregation patterns found in the as-cast billets produced by having two different inlet geometries. The macrosegregation analysis presented here may assist in determining the critical parameters to consider for improving the casting of 7XXX aluminium alloys.

Effect of inlet geometry on macrosegregation during the direct chill casting of 7050 alloy billets: experiments and computer modelling

Science.gov (United States)

Zhang, L.; Eskin, D. G.; Miroux, A.; Subroto, T.; Katgerman, L.

2012-07-01

Controlling macrosegregation is one of the major challenges in direct-chill (DC) casting of aluminium alloys. In this paper, the effect of the inlet geometry (which influences the melt distribution) on macrosegregation during the DC casting of 7050 alloy billets was studied experimentally and by using 2D computer modelling. The ALSIM model was used to determine the temperature and flow patterns during DC casting. The results from the computer simulations show that the sump profiles and flow patterns in the billet are strongly influenced by the melt flow distribution determined by the inlet geometry. These observations were correlated to the actual macrosegregation patterns found in the as-cast billets produced by having two different inlet geometries. The macrosegregation analysis presented here may assist in determining the critical parameters to consider for improving the casting of 7XXX aluminium alloys.

HFIR Fuel Casting Support

Energy Technology Data Exchange (ETDEWEB)

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

2017-09-28

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

Analysis of the Causes of Cracks in a Thick-Walled Bush Made of Die-Cast Aluminum Bronze

Directory of Open Access Journals (Sweden)

Pisarek B.P.

2016-12-01

Full Text Available For the die casting conditions of aluminium bronzes assumed based on the literature data, a thick-walled bush was cast, made of complex aluminium bronze (Cu-Al-Fe-Ni-Cr. After the cast was removed from the mould, cracks were observed inside it. In order to identify the stage in the technological production process at which, potentially, the formation of stresses damaging the continuity of the microstructure created in the cast was possible (hot cracking and/or cold cracking, a computer simulation was performed. The article presents the results of the computer simulation of the process of casting the material into the gravity die as well as solidifying and cooling of the cast in the shape of a thick-walled bush. The simulation was performed with the use of the MAGMA5 program and by application of the CuAl10Ni5,5Fe4,5 alloy from the MAGMA5 program database. The results were compared with the location of the defects identified in the actual cast. As a result of the simulation of the die-casting process of this bush, potential regions were identified where significant principal stresses accumulate, which can cause local hot and cold cracking. Until now, no research has been made of die-cast aluminium bronzes with a Cr addition. Correlating the results of the computer simulation validated by the analysis of the actual cast made it possible to clearly determine the critical regions in the cast exposed to cracking and point to the causes of its occurrence. Proposals of changes in the bush die casting process were elaborated, in order to avoid hot tearing and cold cracking. The article discusses the results of preliminary tests being a prologue to the optimization of the die-casting process parameters of complex aluminium bronze thick-walled bushs.

Engineering design of centrifugal casting machine

Science.gov (United States)

Kusnowo, Roni; Gunara, Sophiadi

2017-06-01

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

Clean Cast Steel Technology, Phase IV

Energy Technology Data Exchange (ETDEWEB)

Charles E. Bates

2003-02-24

The objective of the Clean Cast Steel Technology Program was to improve casting product quality by removing or minimizing oxide defects and to allow the production of higher integrity castings for high speed machining lines. Previous research has concentrated on macro-inclusions that break, chip, or crack machine tool cutters and drills and cause immediate shutdown of the machining lines. The overall goal of the project is to reduce the amount of surface macro-inclusions and improve the machinability of steel castings. Macro-inclusions and improve the machinability of steel castings. Macro-inclusions have been identified by industrial sponsors as a major barrier to improving the quality and marketability of steel castings.

The evaluation of dynamic cracking resistance of chosen casting alloys in the aspect of the impact bending test

Directory of Open Access Journals (Sweden)

J.Sadowski

2008-10-01

Full Text Available The increase of quality and durability of produced casting alloys can be evaluated on the base of material tests performed on a high level. One of such modern test methods are tests of the dynamic damage process of materials and the evaluation on the base of obtained courses F(f, F(t of parameters of dynamic cracking resistance KId, JId, performed with the usage of instrumented Charpy pendulums. In the paper there was presented the evaluation of dynamic cracking resistance parameters of casting alloys such as: AK12 aluminum alloy, L20G cast steel and spheroid cast iron. The methodology of the evaluation of that parameters was described and their change as well, for the AK12 alloy with the cold work different level, L20G cast steel cooled from different temperatures in the range +20oC -60oC, and for the spheroid cast iron in different stages of treatment i.e. raw state, after normalization, spheroid annealing and graphitizing annealing.Obtained parameters of dynamic cracking resistance KId, JId of tested casting alloys enabled to define the critical value of the ad defect that can be tolerated by tested castings in different work conditions with impact loadings.

Hox gene expression leads to differential hind leg development between honeybee castes.

Science.gov (United States)

Bomtorin, Ana Durvalina; Barchuk, Angel Roberto; Moda, Livia Maria; Simoes, Zila Luz Paulino

2012-01-01

Beyond the physiological and behavioural, differences in appendage morphology between the workers and queens of Apis mellifera are pre-eminent. The hind legs of workers, which are highly specialized pollinators, deserve special attention. The hind tibia of worker has an expanded bristle-free region used for carrying pollen and propolis, the corbicula. In queens this structure is absent. Although the morphological differences are well characterized, the genetic inputs driving the development of this alternative morphology remain unknown. Leg phenotype determination takes place between the fourth and fifth larval instar and herein we show that the morphogenesis is completed at brown-eyed pupa. Using results from the hybridization of whole genome-based oligonucleotide arrays with RNA samples from hind leg imaginal discs of pre-pupal honeybees of both castes we present a list of 200 differentially expressed genes. Notably, there are castes preferentially expressed cuticular protein genes and members of the P450 family. We also provide results of qPCR analyses determining the developmental transcription profiles of eight selected genes, including abdominal-A, distal-less and ultrabithorax (Ubx), whose roles in leg development have been previously demonstrated in other insect models. Ubx expression in workers hind leg is approximately 25 times higher than in queens. Finally, immunohistochemistry assays show that Ubx localization during hind leg development resembles the bristles localization in the tibia/basitarsus of the adult legs in both castes. Our data strongly indicate that the development of the hind legs diphenism characteristic of this corbiculate species is driven by a set of caste-preferentially expressed genes, such as those encoding cuticular protein genes, P450 and Hox proteins, in response to the naturally different diets offered to honeybees during the larval period.

Deposition of ultrafine aerosols in F344/N rat nasal casts

Energy Technology Data Exchange (ETDEWEB)

Cheng, Y S; Hansen, G K; Su, Y F; Yeh, H C; Morgan, K T [Chemical Industry Institute of Toxicology, Research Triangle Park, NC (United States)

1988-12-01

Determination of regional respiratory deposition of inhaled aerosols is critical for evaluation of the health effects of air pollutants. Information on deposition of larger particles (> 0.02 {mu}m) in the nasal passages of laboratory animals is available; the deposition fraction increases with increasing particle size. Little information on ultrafine particles less than 0.2 {mu}m is available. Molds (models) were prepared from replica casts of the nasal passages of F344/N rats, using clear casting plastic. Total deposition of ultrafine aerosols in these casts was then determined using a unidirectional flow system. Measured pressure drops in the casts were a function of flow rate to the power of 1.4-1.6, indicating that the flow through the nasal passage was not laminar. Deposition data were obtained from these casts, using monodisperse sodium chloride aerosols with particle size ranging from 0.2 to 0.005 {mu}m, at inspiratory and expiratory flow rates of 200 to 600 cc/min. Similar deposition data were obtained for the three casts studied. The deposition efficiency was greatest for the smallest particles, and decreased with increasing particle size and flow rate, indicating that diffusion was the dominant mechanism for deposition. At an inspiratory flow rate of 400 cc/min, which is comparable to a respiratory minute volume of 200 cc/min for mature male F344/N rats, deposition efficiencies reached 40 and 70% for 0.01 and 0.005 {mu}m particles, respectively. Turbulent diffusion was considered to be the dominant mechanism for deposition of ultrafine particles in the nasal passage. This information is important for understanding the toxicity and carcinogenicity of submicrometer particles, including diesel soot, radon progeny and vapors. (author)

Impact of as-cast structure on structure and properties of twin-roll cast AA8006 alloy

Energy Technology Data Exchange (ETDEWEB)

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

2000-07-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Thangirala, Mani

2015-09-30

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 Haynes 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

Relationship between casting modulus and grain size in cast A356 aluminium alloys

International Nuclear Information System (INIS)

Niklas, A; Abaunza, U; Fernández-Calvo, A I; Lacaze, J

2012-01-01

Microstructure of Al-Si alloy castings depends most generally on melt preparation and on the cooling rate imposed by the thermal modulus of the component. In the case of Al-Si alloys, emphasis is put during melt preparation on refinement of pro-eutectic (Al) grains and on modification of the Al-Si eutectic. Thermal analysis has been used since long to check melt preparation before casting, i.e. by analysis of the cooling curve during solidification of a sample cast in an instrumented cup. The conclusions drawn from such analysis are however valid for the particular cooling conditions of the cups. It thus appeared of interest to investigate how these conclusions could extrapolate to predict microstructure in complicated cast parts showing local changes in the solidification conditions. For that purpose, thermal analysis cups and instrumented sand and die castings with different thermal moduli and thus cooling rates have been made, and the whole set of cooling curves thus recorded has been analysed. A statistical analysis of the characteristic features of the cooling curves related to grain refinement in sand and die castings allowed determining the most significant parameters and expressing the cube of grain size as a polynomial of these parameters. After introduction of a further parameter quantifying melt refining an excellent correlation, with a R 2 factor of 0.99 was obtained.

Optimizing the Gating System for Steel Castings

Directory of Open Access Journals (Sweden)

Jan Jezierski

2018-04-01

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

Wear resistance of cast iron

Directory of Open Access Journals (Sweden)

S. Pietrowski

2008-10-01

Full Text Available In this paper investigations of abrasive and adhesive wear resistance of different cast iron grades have been presented. Examinations showed, that the most advantageous pair of materials is the cast iron – the hardened steel with low-tempered martensite. It was found, that martensitic nodular cast iron with carbides is the most resistant material.

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

Energy Technology Data Exchange (ETDEWEB)

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

1994-06-01

Four subprojects were completed: development and evaluation of die coatings, accelerated die life characterization of die materials, evaluation of fluid flow and solidification modeling programs, selection and characterization of Al-based die casting alloys, and influence of die materials and coatings on die casting quality.

Distinct Circuits for Recovery of Eye Dominance and Acuity in Murine Amblyopia.

Science.gov (United States)

Stephany, Céleste-Élise; Ma, Xiaokuang; Dorton, Hilary M; Wu, Jie; Solomon, Alexander M; Frantz, Michael G; Qiu, Shenfeng; McGee, Aaron W

2018-05-24

Degrading vision by one eye during a developmental critical period yields enduring deficits in both eye dominance and visual acuity. A predominant model is that "reactivating" ocular dominance (OD) plasticity after the critical period is required to improve acuity in amblyopic adults. However, here we demonstrate that plasticity of eye dominance and acuity are independent and restricted by the nogo-66 receptor (ngr1) in distinct neuronal populations. Ngr1 mutant mice display greater excitatory synaptic input onto both inhibitory and excitatory neurons with restoration of normal vision. Deleting ngr1 in excitatory cortical neurons permits recovery of eye dominance but not acuity. Reciprocally, deleting ngr1 in thalamus is insufficient to rectify eye dominance but yields improvement of acuity to normal. Abolishing ngr1 expression in adult mice also promotes recovery of acuity. Together, these findings challenge the notion that mechanisms for OD plasticity contribute to the alterations in circuitry that restore acuity in amblyopia. Copyright © 2018 Elsevier Ltd. All rights reserved.

The evaluation of working casts prepared from digital impressions.

Science.gov (United States)

Hwang, Y C; Park, Y S; Kim, H K; Hong, Y S; Ahn, J S; Ryu, J J

2013-01-01

The aim of this study is to evaluate the reproducibility of working casts of a digital impression system by comparing them with the original, virtual, and rapid prototyping casts. A total of 54 cast sets in clinically stable occlusion were used. They were scanned by an iTero intraoral scanner and converted into STL format virtual casts. Rapid prototyping casts and polyurethane casts were fabricated from the iTero milling system based on the virtual casts. Several horizontal and vertical measurements were performed from the four types of casts, that is, original stone casts, virtual casts, rapid prototyping casts, and polyurethane casts of iTero. Measurement error, intraclass correlation coefficient (ICC), and differences among the casts were calculated and compared. Casts from iTero milling machines exhibited greater dimensional differences and lower ICC values than did other casts. In addition, many of the measurements of the iTero working casts showed statistically significant differences in comparison to the three other types of casts. In contrast, there were no statistically significant differences between the virtual and original casts. Virtual casts made by the iTero intraoral scanner exhibited excellent reproducibility. However, the casts from the iTero milling machine showed greater dimensional differences and lower reproducibility compared to other types of casts.

Temperature and microstructure characteristics of silumin casting AlSi9 made with investment casting method

Directory of Open Access Journals (Sweden)

S. Pietrowski

2011-07-01

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

Segregation in cast products

Indian Academy of Sciences (India)

Unknown

The agreement with experimental data is mostly qualitative. The paper also ... For example, a high degree of positive segregation in the central region .... solute in a cast product, important ones being: size of casting, rate of solidification, mode.

The influence of the parameters of lost foam process on the quality of aluminum alloys castings

Directory of Open Access Journals (Sweden)

Aćimović-Pavlović Zagorka

2010-01-01

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

Genetic structure of Rajaka caste and affinities with other caste populations of Andhra Pradesh, India.

Science.gov (United States)

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.

White cast iron with a nano-eutectic microstructure and high tensile strength and considerable ductility prepared by an aluminothermic reaction casting

International Nuclear Information System (INIS)

La, Peiqing; Wei, Fuan; Hu, Sulei; Li, Cuiling; Wei, Yupeng

2013-01-01

A white cast iron with nano-eutectic microstructure was prepared by an aluminothermic reaction casting. Microstructures of the cast iron were investigated by optical microscope (OM), electron probe micro-analyzer (EPMA), scanning electron microscope (SEM) and X-ray diffraction (XRD). Mechanical properties of the cast iron were tested. The results showed that the cast iron consisted of pearlite and cementite phases. Lamellar spacing of the pearlite phase was in a range of 110–275 nm and much smaller than that of the Ni-Hard 2 cast iron. Hardness of the cast iron was 552 Hv, tensile strength was 383 MPa, total elongation was 3% and compressive strength was 2224 MPa. Tensile strength and hardness of the cast iron was same to Ni-Hard 2 cast iron, besides the ductility was much better than that of the Ni-Hard 2 cast iron which is much expensive than the cast iron.

Method for casting thin metal objects

Science.gov (United States)

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.

The Effect of Applied Pressure During Feeding of Critical Cast Aluminum Alloy Components With Particular Reference to Fatigue Resistance

Energy Technology Data Exchange (ETDEWEB)

J.T. Berry; R. Luck; B. Zhang; R.P. Taylor

2003-06-30

the medium to long freezing range alloys of aluminum such as A356, A357, A206, 319 for example are known to exhibit dispersed porosity, which is recognized as a factor affecting ductility, fracture toughness, and fatigue resistance of light alloy castings. The local thermal environment, for example, temperature gradient and freezing from velocity, affect the mode of solidification which, along with alloy composition, heat treatment, oxide film occlusion, hydrogen content, and the extent to which the alloy contracts on solidification, combine to exert strong effects on the porosity formation in such alloys. In addition to such factors, the availability of liquid metal and its ability to flow through the partially solidified casting, which will be affect by the pressure in the liquid metal, must also be considered. The supply of molten metal will thus be controlled by the volume of the riser available for feeding the particular casting location, its solidification time, and its location together with any external pressure that might be applied at the riser.

Modelling of flow phenomena during DC casting

NARCIS (Netherlands)

Zuidema, J.

2005-01-01

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

Mechanical properties of as-cast microalloyed steels produced via investment casting

International Nuclear Information System (INIS)

Najafi, H.; Rassizadehghani, J.; Norouzi, S.

2011-01-01

Tensile and room temperature Charpy V-notch impact tests were used to evaluate the variations in the as-cast mechanical properties of a low-carbon steel produced via shell mould investment casting and containing combinations of vanadium, niobium and titanium. Tensile results indicate that the yield strength and ultimate tensile strength (UTS) have increased up to respectively 615 MPa and 770 MPa due to the fine-scale microalloy precipitates in the microalloyed samples. Room temperature impact test results show that while addition of vanadium individually has not changed the impact energy, Nb has decreased it considerably. However, examination of fracture surfaces reveals that all microalloyed samples have failed by transgranular cleavage. Based on the transmission electron microscope (TEM) studies, it seems that carbonitrides being greater than 50 nm in size and formed along prior austenite grain boundaries before γ transformation are responsible for the observed reduction in impact energies and brittle fracture. In comparison to sand mould casting, the yield and UTS obtained from investment casting are superior. Furthermore, although the impact energies of Nb-containing alloys are approximately the same as those obtained from sand moulds, the impact energy of the alloy containing only vanadium has improved considerably.

Spatial Bimetallic Castings Manufactured from Iron Alloys

Directory of Open Access Journals (Sweden)

M. Cholewa

2007-07-01

Full Text Available In this paper a conception for manufacturing method of skeleton castings with composite features was shown. Main application of such castings are the working organs of machines subjected to intensive abrasive and erosive wear. Skeleton geometry was based on three-dimensional cubic net consisting of circular connectors and nodes joining 6 connectors according to Cartesian co-ordinate system. Dimension of an elementary cell was equal to 10 mm and diameter of single connector was equal to 5 mm. For bimetallic castings preparation two Fe based alloys were used: L25SHMN cast steel for skeleton substrate and ZlCr15NiMo cast iron for working part of the casting. In presented work obtained structure was analyzed with indication of characteristic regions. Authors described phenomena occurring at the alloys interface and phases in transition zone. A thesis was formulated concerning localization of transition zone at the cast iron matrix – cast steel reinforcement interface. Direction of further studies were indicated.

Modelling of Filling, Microstructure Formation, Local Mechanical Properties and Stress – Strain Development in High-Pressure Die Cast Aluminium Castings

DEFF Research Database (Denmark)

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

2009-01-01

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

THROUGH THE EYES OF THE LEARNER: A CRITICAL EVALUATION OF AN URBAN INDIAN SCHOOL

Directory of Open Access Journals (Sweden)

Smita Khan

2012-07-01

Full Text Available India, being the second most populated country in the world, a sizable school going population is the result of a positive and proactive response to the governmental efforts on basic education. This has catapulted the responsibility of schools and their environs in shaping young impressionable minds due to their sheer number. This study aims at exploring and investigating qualities and characteristics of an urban Indian school through critical post occupancy evaluation of the school environs through the eyes of the children. To initiate this study, a premier school of Nagpur city, exemplifying a typical urban school, was identified for a pilot study. The methodology encompassed interviewing the Principal, observation by the researchers and interaction with students to understand and critically analyze usage pattern by principal users of the school. The design of the tools for user response was devised keeping in mind the age of the students and their ability to communicate spatial experiences. The paper served as a fact-finding mission and in its outcomes led to an identification of the major variables of the spatial environs of schools. It brought to fore an understanding, which the mandatory prerequisites of school infrastructure lack in a humane vision that is so imperative to educational environments. It facilitated in pinpointing the lacunae existing in the National Curriculum Framework, which is a governmental guideline for all schools in India. In conclusion, the article emphasizes the urgency in the necessary ‘humanization’ of the schools to the happiness and contentment of the young who are nurtured within its spaces.

Influence of heat treatment on microstructure and properties of bainitic cast steel used for frogs in railway crossovers

Directory of Open Access Journals (Sweden)

E. Tasak

2010-01-01

Full Text Available This work deals with influence of heat treatment on microstructure and properties of sample cast assigned as a material used for frogs in railway crossover. Materials used in railway industry for frogs (manganese cast steel and forged pearlitic steel do not fulfil strict conditions of exploitation of railway. One of the solutions is using cast steel with bainitic or bainite-martensite microstructure, what allows to gain high resistance properties (Rm = 1400 MPa, Rp0,2 = 900 MPa, hardness to 400 HBW. The cooling rates of rail type UIC60 shows that it is possible to reach the bainitic microstructure in cast of frog. The microstructure of lower banite should have an advantageous influence on cracking resistance. In order to set the parameters of heat treatment, the critical temperatures were determined by dilatometric methods determined. This heat treatment consisted of normalizing that prepared it to the farther process of resistance welding. Moreover, the CCT diagram of proposed bainitic cast steel was prepared. The exams were done that can be used to evaluate the influence of heat treatment on microstructure and properties of the sample cast.

Aging degradation of cast stainless steel: status and program

Energy Technology Data Exchange (ETDEWEB)

Chopra, O.K.; Ayrault, G.

1983-10-01

A program has been initiated to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water reactor operating conditions. The existing data are reviewed to determine the critical parameters that control the aging behavior and to define the objectives and scope of the investigation. The test matrices for microstructural studies and mechanical property measurements are presented. The initial experimental effort is focussed on characterizing the microstructure of long-term, low-temperature aged material. Specimens from three heats of cast CF-8 and CF-8M stainless steel aged for up to 70,000 h at 300, 350, and 400/sup 0/C were obtained from George Fisher Ltd., of Switzerland. Initial analyses reveal the formation of three different types of precipitates which are not ..cap alpha..'. An FCC phase, similar to the M/sub 23/C/sub 6/ precipitates, was present in all the long-term aged material. 15 references, 10 figures, 2 tables.

Aging degradation of cast stainless steel: status and program

International Nuclear Information System (INIS)

Chopra, O.K.; Ayrault, G.

1983-10-01

A program has been initiated to investigate the significance of in-service embrittlement of cast duplex stainless steels under light-water reactor operating conditions. The existing data are reviewed to determine the critical parameters that control the aging behavior and to define the objectives and scope of the investigation. The test matrices for microstructural studies and mechanical property measurements are presented. The initial experimental effort is focussed on characterizing the microstructure of long-term, low-temperature aged material. Specimens from three heats of cast CF-8 and CF-8M stainless steel aged for up to 70,000 h at 300, 350, and 400 0 C were obtained from George Fisher Ltd., of Switzerland. Initial analyses reveal the formation of three different types of precipitates which are not α'. An FCC phase, similar to the M 23 C 6 precipitates, was present in all the long-term aged material. 15 references, 10 figures, 2 tables

Epithelial morphogenesis: the mouse eye as a model system.

Science.gov (United States)

Chauhan, Bharesh; Plageman, Timothy; Lou, Ming; Lang, Richard

2015-01-01

Morphogenesis is the developmental process by which tissues and organs acquire the shape that is critical to their function. Here, we review recent advances in our understanding of the mechanisms that drive morphogenesis in the developing eye. These investigations have shown that regulation of the actin cytoskeleton is central to shaping the presumptive lens and retinal epithelia that are the major components of the eye. Regulation of the actin cytoskeleton is mediated by Rho family GTPases, by signaling pathways and indirectly, by transcription factors that govern the expression of critical genes. Changes in the actin cytoskeleton can shape cells through the generation of filopodia (that, in the eye, connect adjacent epithelia) or through apical constriction, a process that produces a wedge-shaped cell. We have also learned that one tissue can influence the shape of an adjacent one, probably by direct force transmission, in a process we term inductive morphogenesis. Though these mechanisms of morphogenesis have been identified using the eye as a model system, they are likely to apply broadly where epithelia influence the shape of organs during development. © 2015 Elsevier Inc. All rights reserved.

Evaluation of porosity in Al alloy die castings

Directory of Open Access Journals (Sweden)

M. Říhová

2012-01-01

Full Text Available Mechanical properties of an Al-alloy die casting depend significantly on its structural properties. Porosity in Al-alloy castings is one of the most frequent causes of waste castings. Gas pores are responsible for impaired mechanical-technological properties of cast materials. On the basis of a complex evaluation of experiments conducted on AlSi9Cu3 alloy samples taken from the upper engine block which was die- cast with and without local squeeze casting it can be said that castings manufactured without squeeze casting exhibit maximum porosity in the longitudinal section. The area without local squeeze casting exhibits a certain reduction in mechanical properties and porosity increased to as much as 5%. However, this still meets the norms set by SKODA AUTO a.s.

Some Theoretical Considerations on Caste

Directory of Open Access Journals (Sweden)

Madhusudan Subedi

2014-05-01

Full Text Available Caste as a system of social stratification was an encompassing system in the past. There was reciprocal system of exchange goods and services. With time, occupation and mode of generation of livelihood of various caste groups changed, and the traditional form of jajmani system fizzled out. This paper provides an account of changing perspectives of caste relations in social science writing and political discourse. The discourse of caste has been shifted from ritual hierarchy and social discrimination to an instrument to mobilize people for economic and political gain. DOI: http://dx.doi.org/10.3126/dsaj.v7i0.10437 Dhaulagiri Journal of Sociology and Anthropology Vol. 7, 2013; 51-86

Fabrication of sacrificial anode cathodic protection through casting method

International Nuclear Information System (INIS)

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

2007-01-01

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

Tradeoffs in the evolution of caste and body size in the hyperdiverse ant genus Pheidole.

Directory of Open Access Journals (Sweden)

Terrence P McGlynn

Full Text Available The efficient investment of resources is often the route to ecological success, and the adaptability of resource investment may play a critical role in promoting biodiversity. The ants of the "hyperdiverse" genus Pheidole produce two discrete sterile castes, soldiers and minor workers. Within Pheidole, there is tremendous interspecific variation in proportion of soldiers. The causes and correlates of caste ratio variation among species of Pheidole remain enigmatic. Here we test whether a body size threshold model accounts for interspecific variation in caste ratio in Pheidole, such that species with larger body sizes produce relatively fewer soldiers within their colonies. We evaluated the caste ratio of 26 species of Pheidole and found that the body size of workers accounts for interspecific variation in the production of soldiers as we predicted. Twelve species sampled from one forest in Costa Rica yielded the same relationship as found in previously published data from many localities. We conclude that production of soldiers in the most species-rich group of ants is regulated by a body size threshold mechanism, and that the great variation in body size and caste ratio in Pheidole plays a role in niche divergence in this rapidly evolving taxon.

14 CFR 29.621 - Casting factors.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Casting factors. 29.621 Section 29.621... STANDARDS: TRANSPORT CATEGORY ROTORCRAFT Design and Construction General § 29.621 Casting factors. (a... approved specifications. Paragraphs (c) and (d) of this section apply to structural castings except...

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

Science.gov (United States)

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

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

Directory of Open Access Journals (Sweden)

A. Studnicki

2008-08-01

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

Casting Footprints for Eternity

Science.gov (United States)

1999-01-01

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

Casting fine grained, fully dense, strong inorganic materials

Science.gov (United States)

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.

Rebamipide ophthalmic suspension for the treatment of dry eye syndrome: a critical appraisal

Directory of Open Access Journals (Sweden)

Kashima T

2014-05-01

Full Text Available Tomoyuki Kashima,1 Hirotaka Itakura,1,2 Hideo Akiyama,1 Shoji Kishi11Department of Ophthalmology, Gunma University, School of Medicine, Maebashi, Gunma, Japan; 2Department of Ophthalmology, Maebashi Red Cross Hospital, Maebashi, Gunma, JapanAbstract: Rebamipide was initially developed and approved for use in treating gastric ulcers and lesions associated with gastritis. Discovery of its ability to increase gastric mucin led to investigations of its effect on ocular surface mucin and the subsequent development for use in dry eye patients. Investigations have confirmed that rebamipide increases corneal and conjunctival mucin-like substances along with improving corneal and conjunctival injury. Clinically, rebamipide ophthalmic suspensions can effectively treat tear deficiency and mucin-caused corneal epithelial damage, and can restore the microstructure responsible for tear stability. Topical rebamipide has also been shown to be effective in treating other ocular surface disorders such as lagophthalmos, lid wiper epitheliopathy, and persistent corneal erosion. Rebamipide’s ability to modify epithelial cell function, improve tear stability, and suppress inflammation in the absence of any known major side effects suggest that it may be a beneficial first drug of choice for severe dry eye treatment and other ocular surface disorders. This review summarizes the history and development of this innovative dry eye treatment from its initial use as an effective stomach medication to its current use in the treatment of dry eye in Japan.Keywords: quinolinone derivative, tear deficiency, ocular surface disorder, mucin secretion, Mucosta

14 CFR 25.621 - Casting factors.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Casting factors. 25.621 Section 25.621... STANDARDS: TRANSPORT CATEGORY AIRPLANES Design and Construction General § 25.621 Casting factors. (a... meet approved specifications. Paragraphs (c) and (d) of this section apply to any structural castings...

14 CFR 27.621 - Casting factors.

Science.gov (United States)

2010-01-01

... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Casting factors. 27.621 Section 27.621... STANDARDS: NORMAL CATEGORY ROTORCRAFT Design and Construction General § 27.621 Casting factors. (a) General... approved specifications. Paragraphs (c) and (d) of this section apply to structural castings except...

Abrasion Resistance of as-Cast High-Chromium Cast Iron

Directory of Open Access Journals (Sweden)

Pokusová Marcela

2014-12-01

Full Text Available High chromium cast irons are widely used as abrasion resistant materials. Their properties and wear resistance depend on carbides and on the nature of the matrix supporting these carbides. The paper presents test results of irons which contain (in wt.% 18-22 Cr and 2-5 C, and is alloyed by 1.7 Mo + 5 Ni + 2 Mn to improve the toughness. Tests showed as-cast irons with mostly austenitic matrix achieved hardness 36-53 HRC but their relative abrasion-resistance was higher than the tool steel STN 19436 heat treated on hardness 60 HRC.

SU-F-T-51: Investigating the Effect of Eye Size and Eccentricity On Normal Tissue Doses From Eye Plaque Brachytherapy

Energy Technology Data Exchange (ETDEWEB)

Polsdofer, E; Crilly, R [Oregon Health & Science University Portland, OR (United States)

2016-06-15

Purpose: This study investigates the effect of eye size and eccentricity on doses to critical tissues by simulating doses in the Plaque Simulator (v. 6.3.1) software. Present OHSU plaque brachytherapy treatment focuses on delivering radiation to the tumor measured with ocular ultrasound plus a small margin and assumes the orbit has the dimensions of a “standard eye.” Accurately modeling the dimensions of the orbit requires a high resolution ocular CT. This study quantifies how standard differences in equatorial diameters and eccentricity affect calculated doses to critical structures in order to query the justification of the additional CT scan to the treatment planning process. Methods: Tumors of 10 mm × 10 mm × 5 mm were modeled at the 12:00:00 hour with a latitude of 45 degrees. Right eyes were modeled at a number of equatorial diameters from 17.5 to 28 mm for each of the standard non-notched COMS plaques with silastic inserts. The COMS plaques were fully loaded with uniform activity, centered on the tumor, and prescribed to a common tumor dose (85 Gy/100 hours). Variations in the calculated doses to normal structures were examined to see if the changes were significant. Results: The calculated dose to normal structures show a marked dependence on eye geometry. This is exemplified by fovea dose which more than doubled in the smaller eyes and nearly halved in the larger model. Additional significant dependence was found in plaque size on the calculated dose in spite of all plaques giving the same dose to the prescription point. Conclusion: The variation in dose with eye dimension fully justifies the addition of a high resolution ocular CT to the planning technique. Additional attention must be made to plaque size beyond simply covering the tumor when considering normal tissue dose.

Novel casting processes for single-crystal turbine blades of superalloys

Science.gov (United States)

Ma, Dexin

2018-03-01

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

CASTING METHOD AND APPARATUS

Science.gov (United States)

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

1958-10-01

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

Pressure distribution in centrifugal dental casting.

Science.gov (United States)

Nielsen, J P

1978-02-01

Equations are developed for liquid metal pressure in centrifugal dental casting, given the instantaneous rotational velocity, density, and certain dimensions of the casting machine and casting pattern. A "reference parabola" is introduced making the fluid pressure concept more understandable. A specially designed specimen demonstrates experimentally the reference parabola at freezing.

Study on Compatibility between Converters and Casting Machines for Daily Steelmaking and Continuous Casting Scheduling

Institute of Scientific and Technical Information of China (English)

MA Feng-cai; ZHANG Qun

2009-01-01

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

Ponseti casting: a new soft option.

Science.gov (United States)

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

2008-11-01

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

More to it than meets the eye: how eye movements can elucidate the development of episodic memory.

Science.gov (United States)

Pathman, Thanujeni; Ghetti, Simona

2016-07-01

The ability to recognise past events along with the contexts in which they occurred is a hallmark of episodic memory, a critical capacity. Eye movements have been shown to track veridical memory for the associations between events and their contexts (relational binding). Such eye-movement effects emerge several seconds before, or in the absence of, explicit response, and are linked to the integrity and function of the hippocampus. Drawing from research from infancy through late childhood, and by comparing to investigations from typical adults, patient populations, and animal models, it seems increasingly clear that eye movements reflect item-item, item-temporal, and item-spatial associations in developmental populations. We analyse this line of work, identify missing pieces in the literature and outline future avenues of research, in order to help elucidate the development of episodic memory.

Modeling of mouse eye and errors in ocular parameters affecting refractive state

Science.gov (United States)

Bawa, Gurinder

Rodents eye are particularly used to study refractive error state of an eye and development of refractive eye. Genetic organization of rodents is similar to that of humans, which makes them interesting candidates to be researched upon. From rodents family mice models are encouraged over rats because of availability of genetically engineered models. Despite of extensive work that has been performed on mice and rat models, still no one is able to quantify an optical model, due to variability in the reported ocular parameters. In this Dissertation, we have extracted ocular parameters and generated schematics of eye from the raw data from School of Medicine, Detroit. In order to see how the rays would travel through an eye and the defects associated with an eye; ray tracing has been performed using ocular parameters. Finally we have systematically evaluated the contribution of various ocular parameters, such as radii of curvature of ocular surfaces, thicknesses of ocular components, and refractive indices of ocular refractive media, using variational analysis and a computational model of the rodent eye. Variational analysis revealed that variation in all the ocular parameters does affect the refractive status of the eye, but depending upon the magnitude of the impact those parameters are listed as critical or non critical. Variation in the depth of the vitreous chamber, thickness of the lens, radius of the anterior surface of the cornea, radius of the anterior surface of the lens, as well as refractive indices for the lens and vitreous, appears to have the largest impact on the refractive error and thus are categorized as critical ocular parameters. The radii of the posterior surfaces of the cornea and lens have much smaller contributions to the refractive state, while the radii of the anterior and posterior surfaces of the retina have no effect on the refractive error. These data provide the framework for further refinement of the optical models of the rat and mouse

Improved Casting Furnace Conceptual Design

Energy Technology Data Exchange (ETDEWEB)

Fielding, Randall Sidney [Idaho National Lab. (INL), Idaho Falls, ID (United States); Tolman, David Donald [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2017-02-01

In an attempt to ensure more consistent casting results and remove some schedule variance associated with casting, an improved casting furnace concept has been developed. The improved furnace uses the existing arc melter hardware and glovebox utilities. The furnace concept was designed around physical and operational requirements such as; a charge sized of less than 30 grams, high heating rates and minimal additional footprint. The conceptual model is shown in the report as well as a summary of how the requirements were met.

Numerical microstructure prediction for an aluminium casting and its experimental validation

OpenAIRE

Unterreiter Guenter; Ludwig Andreas; Wu Menghuai

2011-01-01

Virtual manufacturing based on through-process modelling becomes an evolving research area which aims at integrating diverse simulation tools to realize computer-aided design, analysis, prototyping and manufacturing. Numerical prediction of the as-cast microstructure is an initial and critical step in the whole through-process modelling chain for engineering components. A commercial software package with the capability of calculating important microstructure features for aluminium alloys is u...

Casting defects and mechanical properties of high pressure die cast Mg-Zn-Al-RE alloys

Energy Technology Data Exchange (ETDEWEB)

Xiao, Wenlong; Easton, Mark A.; Zhu, Suming; Nie, Jianfeng [CAST Cooperative Research Centre, Department of Materials Engineering Monash University, Melbourne, VIC (Australia); Dargusch, Matthew S. [School of Mechanical and Mining Engineering, University of Queensland, Brisbane, QLD (Australia); Gibson, Mark A. [CSIRO Process Science and Engineering, Melbourne, VIC (Australia); Jia, Shusheng [Key Laboratory of Automobile Materials, Ministry of Education, Department of Materials Science and Engineering Jilin University, Changchun (China)

2012-02-15

The die casting defects and tensile properties of high pressure die cast (HPDC) Mg-Zn-Al-RE alloys with various combinations of Zn and Al were studied. The results show that die casting defects in Mg-Zn-Al-RE alloys are affected by the percentage of Zn and Al contents. The hot tearing susceptibility (HTS) of Mg-Zn-Al-RE alloys tends to increase with increasing Zn content up to 6 wt%, while a further increase of Al and/or Zn content reduces the HTS. In tensile tests, the yield strength (YS) is generally improved by increasing Zn or Al content, whereas the tensile strength (TS) and ductility appear to depend largely on the presence of casting defects. Compared with Mg-Zn-Al alloys, the mechanical properties of the Mg-Zn-Al-RE alloy are significantly improved. The Mg-4Zn-4Al-4RE alloy is found to have few casting defects and the optimal tensile properties. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

EyeMusic: Making Music with the Eyes

OpenAIRE

Hornof, Anthony J.; Sato, Linda

2004-01-01

Though musical performers routinely use eye movements to communicate with each other during musical performances, very few performers or composers have used eye tracking devices to direct musical compositions and performances. EyeMusic is a system that uses eye movements as an input to electronic music compositions. The eye movements can directly control the music, or the music can respond to the eyes moving around a visual scene. EyeMusic is implemented so that any composer using established...

Low Loss Advanced Metallic Fuel Casting Evaluation

International Nuclear Information System (INIS)

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

2014-01-01

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

Early visual evoked potentials are modulated by eye position in humans induced by whole body rotations

Directory of Open Access Journals (Sweden)

Petit Laurent

2004-09-01

Full Text Available Abstract Background To reach and grasp an object in space on the basis of its image cast on the retina requires different coordinate transformations that take into account gaze and limb positioning. Eye position in the orbit influences the image's conversion from retinotopic (eye-centered coordinates to an egocentric frame necessary for guiding action. Neuroimaging studies have revealed eye position-dependent activity in extrastriate visual, parietal and frontal areas that is along the visuo-motor pathway. At the earliest vision stage, the role of the primary visual area (V1 in this process remains unclear. We used an experimental design based on pattern-onset visual evoked potentials (VEP recordings to study the effect of eye position on V1 activity in humans. Results We showed that the amplitude of the initial C1 component of VEP, acknowledged to originate in V1, was modulated by the eye position. We also established that putative spontaneous small saccades related to eccentric fixation, as well as retinal disparity cannot explain the effects of changing C1 amplitude of VEP in the present study. Conclusions The present modulation of the early component of VEP suggests an eye position-dependent activity of the human primary visual area. Our findings also evidence that cortical processes combine information about the position of the stimulus on the retinae with information about the location of the eyes in their orbit as early as the stage of primary visual area.

The effect of cast-to-cast variations on the quality of thin section nickel alloy welded joints

International Nuclear Information System (INIS)

Lambert, J.A.

1989-02-01

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

Influence of microscopic casting defects on fatigue endurance of ductile cast iron

Directory of Open Access Journals (Sweden)

Nový František

2018-01-01

Full Text Available In this work, there are published results about fatigue endurance of ductile cast iron obtained at high-frequency sinusoidal cyclic push-pull loading in the ultra-high cycle fatigue region. The main attention was focused on the fatigue lifetime data scatter caused by the influence of microscopic casting defects (microshrinkages, microbubbles, microcracks, non-metallic inclusions and local clusters of big graphitic nodules.

Caste in Itself, Caste and Class, or Caste in Class

OpenAIRE

Ramkrishna Mukherjee

2015-01-01

After the British conquered Bengal and eventually the whole of India,they set out to administer the colony. In this context they encountered two phenomena with which they were not familiar: (1) the relation of people to land for production (and not for revenue receiving, household living, etc.), and (2) the caste system of India, viz. the jati strati?cation of society.

Effect of parameters of high-pressure die casting on occurrence of casting nonconformities in sleeves of silumin alloy EN AB 47100

Directory of Open Access Journals (Sweden)

Pałyga Ł.

2017-03-01

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

Developing technological process of obtaining giality casts

Directory of Open Access Journals (Sweden)

A. Issagulov

2014-10-01

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

Simulation of the injection casting of metallic fuels

International Nuclear Information System (INIS)

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

1989-01-01

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

Development of vacuum continuous casting technology for uranium

International Nuclear Information System (INIS)

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

2001-02-01

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

Clusterin Seals the Ocular Surface Barrier in Mouse Dry Eye.

Science.gov (United States)

Bauskar, Aditi; Mack, Wendy J; Mauris, Jerome; Argüeso, Pablo; Heur, Martin; Nagel, Barbara A; Kolar, Grant R; Gleave, Martin E; Nakamura, Takahiro; Kinoshita, Shigeru; Moradian-Oldak, Janet; Panjwani, Noorjahan; Pflugfelder, Stephen C; Wilson, Mark R; Fini, M Elizabeth; Jeong, Shinwu

2015-01-01

Dry eye is a common disorder caused by inadequate hydration of the ocular surface that results in disruption of barrier function. The homeostatic protein clusterin (CLU) is prominent at fluid-tissue interfaces throughout the body. CLU levels are reduced at the ocular surface in human inflammatory disorders that manifest as severe dry eye, as well as in a preclinical mouse model for desiccating stress that mimics dry eye. Using this mouse model, we show here that CLU prevents and ameliorates ocular surface barrier disruption by a remarkable sealing mechanism dependent on attainment of a critical all-or-none concentration. When the CLU level drops below the critical all-or-none threshold, the barrier becomes vulnerable to desiccating stress. CLU binds selectively to the ocular surface subjected to desiccating stress in vivo, and in vitro to the galectin LGALS3, a key barrier component. Positioned in this way, CLU not only physically seals the ocular surface barrier, but it also protects the barrier cells and prevents further damage to barrier structure. These findings define a fundamentally new mechanism for ocular surface protection and suggest CLU as a biotherapeutic for dry eye.

Clusterin Seals the Ocular Surface Barrier in Mouse Dry Eye.

Directory of Open Access Journals (Sweden)

Aditi Bauskar

Full Text Available Dry eye is a common disorder caused by inadequate hydration of the ocular surface that results in disruption of barrier function. The homeostatic protein clusterin (CLU is prominent at fluid-tissue interfaces throughout the body. CLU levels are reduced at the ocular surface in human inflammatory disorders that manifest as severe dry eye, as well as in a preclinical mouse model for desiccating stress that mimics dry eye. Using this mouse model, we show here that CLU prevents and ameliorates ocular surface barrier disruption by a remarkable sealing mechanism dependent on attainment of a critical all-or-none concentration. When the CLU level drops below the critical all-or-none threshold, the barrier becomes vulnerable to desiccating stress. CLU binds selectively to the ocular surface subjected to desiccating stress in vivo, and in vitro to the galectin LGALS3, a key barrier component. Positioned in this way, CLU not only physically seals the ocular surface barrier, but it also protects the barrier cells and prevents further damage to barrier structure. These findings define a fundamentally new mechanism for ocular surface protection and suggest CLU as a biotherapeutic for dry eye.

The effects of casting speed on steel continuous casting process

Energy Technology Data Exchange (ETDEWEB)

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

2011-12-15

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

Optimization of squeeze casting parameters for non symmetrical AC2A aluminium alloy castings through Taguchi method

International Nuclear Information System (INIS)

Senthil, P.; Amirthagadeswaran, K. S.

2012-01-01

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

Long term stability analysis of cast iron shaft linings after Coal Mine closure and flooding

Energy Technology Data Exchange (ETDEWEB)

Hadj-Hassen, F. [Ecole des Mines de Paris - CGES, 77 - Fontainebleau (France); Bienvenu, Y. [Ecole des Mines de Paris, CM, 91 - Evry (France); Noirel, J.F. [Charbonnages de France, DTN, 57 - Freyming Merlebach (France); Metz, M. [charbonnages de France, ESA, 57 - Freyming Merlebach (France)

2005-07-01

This paper presents the results of a study conducted to analyse the long term stability of the cast iron shaft lining after coal mine closure and flooding. The attention is mainly focused on the behaviour during the critical phase of flooding as well as the phase corresponding to the disappearance of the water pressure and the stabilization of the environment. This pluri-disciplinary study was conducted by a team combining specialists in rock mechanics who identified the main risks and the conditions of stability of the lining and specialists in metallurgy who studied the composition of the cast iron and its corrosion behaviour after exposure to mine water. (authors)

Long term stability analysis of cast iron shaft linings after Coal Mine closure and flooding

International Nuclear Information System (INIS)

Hadj-Hassen, F.; Bienvenu, Y.; Noirel, J.F.; Metz, M.

2005-01-01

This paper presents the results of a study conducted to analyse the long term stability of the cast iron shaft lining after coal mine closure and flooding. The attention is mainly focused on the behaviour during the critical phase of flooding as well as the phase corresponding to the disappearance of the water pressure and the stabilization of the environment. This pluri-disciplinary study was conducted by a team combining specialists in rock mechanics who identified the main risks and the conditions of stability of the lining and specialists in metallurgy who studied the composition of the cast iron and its corrosion behaviour after exposure to mine water. (authors)

Tape casting fluorinated YBC123

International Nuclear Information System (INIS)

Taylor, J.A.T.; Luke, D.M.; Whiteley, B.A.

1991-01-01

Tape casting the superconducting Ba-Y-Cu oxide was accomplished by several laboratories and show promise for being a versatile forming technique. The major problem is low current density, probably due to lack of grain alignment and grain boundary related weak links. The latter problem may be due to formation of carbonates and hydroxides during binder burnout. Preliminary work done at Alfred shows that a bimodal powder size distribution displays significant alignment after tape casting and that F treated powder is resistant to attack by steam at 100C. Such corrosion resistant powder cast as form tape should survive the binder burnout without the detrimental grain boundary phases that develop from reaction of the superconducting phase, steam and carbon dioxide. This paper presents the results of an investigation of tape casting fluorinated powder with a bimodal size distribution

Seal welded cast iron nuclear waste container

International Nuclear Information System (INIS)

Filippi, A.M.; Sprecace, R.P.

1987-01-01

An article of manufacture is described comprising a cast iron container having an opening at one end and a cast iron plug; a first nickel-carbon alloy fusion weldable insert surrounding the opening and metallurgically bonded to the cast iron container at the one end of the container; a second nickel-carbon alloy insert metallurgically bonded to the cast iron plug located within the opening and surrounded by the first insert the inserts being jointed by a fusion bond in the opening without heating the cast iron container to an austenite formation temperature thereby sealing the interior of the container from the exterior ambient outside the opening; the nickel-carbon alloy containing about 2 to 5 w% carbon; and both the nickel-carbon alloy insert and the cast iron container have a microstructure containing a graphite phase

Centrifugal Casting Features/Metallurgical Characterization of Aluminum Alloys

International Nuclear Information System (INIS)

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

2008-01-01

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

Connecting eye to eye

DEFF Research Database (Denmark)

Dau, Susanne; Rask, Anders Bindslev

2017-01-01

Computer Supported Collaborative Learning (CSCL) is used a frame for supporting online and blended learning in educations. The online communication and collaboration are afforded by the social collaboration. However, the social collaboration is based on the establishment of direct eye contact...... (Khalid, Deska & Hugenberg, 2016), but direct eye contact is challenged by the position of the digital devices and thus CSCL. Lack of eye contact is the chief contributor to the negative effects of online disinhibition (Lapidot-Lefler & Barak, 2012) and the problem is the location of the web camera...... at the computer. Eye contact is challenged by the displacement between the senders´ and receivers´ focus on the screen picture and the camera's location at the top or bottom of screens on all digital devices. The aim of this paper is accordingly to investigate the influence of the displacement in eye contact...

Novel technologies for the lost foam casting process

Science.gov (United States)

Jiang, Wenming; Fan, Zitian

2018-03-01

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

Cardiovascular cast model fabrication and casting effectiveness evaluation in fetus with severe congenital heart disease or normal heart.

Science.gov (United States)

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.

Caste in Itself, Caste and Class, or Caste in Class

Directory of Open Access Journals (Sweden)

Ramkrishna Mukherjee

2015-08-01

Full Text Available After the British conquered Bengal and eventually the whole of India,they set out to administer the colony. In this context they encountered two phenomena with which they were not familiar: (1 the relation of people to land for production (and not for revenue receiving, household living, etc., and (2 the caste system of India, viz. the jati strati?cation of society.

Solidification of cast iron - A study on the effect of microalloy elements on cast iron

DEFF Research Database (Denmark)

Moumeni, Elham

The present thesis deals with the heat transfer and solidification of ductile and microalloyed grey cast iron. Heterogeneous nucleation of nodular graphite at inclusions in ductile iron during eutectic solidification has been investigated. A series of ductile iron samples with two different...... of the austenite, in the last region to solidify. The superfine graphite which forms in this type of irons is short (10-20µm) and stubby. The microstructure of this kind of graphite flakes in titanium alloyed cast iron is studied using electron microscopy techniques. The methods to prepare samples of cast iron...... for comprehensive transmission electron microscopy of graphite and the surrounding iron matrix have been developed and explained. Dual beam microscopes are used for sample preparation. A TEM study has been carried out on graphite flakes in grey cast iron using selected area electron diffraction (SAED). Based...

Structure fields in the solidifying cast iron roll

Directory of Open Access Journals (Sweden)

W.S. Wołczyński

2010-01-01

Full Text Available Some properties of the rolls depend on the ratio of columnar structure area to equiaxed structure area created during roll solidification. The transition is fundamental phenomenon that can be apply to characterize massive cast iron rolls produced by the casting house. As the first step of simulation, a temperature field for solidifying cast iron roll was created. The convection in the liquid is not comprised since in the first approximation, the convection does not influence the studied occurrence of the (columnar to equiaxed grains transition in the roll. The obtained temperature field allows to study the dynamics of its behavior observed in the middle of the mould thickness. This midpoint of the mould thickness was treated as an operating point for the transition. A full accumulation of the heat in the mould was postulated for the transition. Thus, a plateau at the curve was observed at the midpoint. The range of the plateau existence corresponded to the incubation period , that appeared before fully equiaxed grains formation. At the second step of simulation, behavior of the thermal gradients field was studied. Three ranges within the filed were visible: EC→EC→EC→EC→(tTECtt↔RERCtt↔a/ for the formation of columnar structure (the C – zone: ( and 0>>T&0>>=−>−=REREttGttG.The columnar structure formation was significantly slowed down during incubation period. It resulted from a competition between columnar growth and equiaxed growth expected at that period of time. The 0≈=−=RERCttGttG relationship was postulated to correspond well with the critical thermal gradient, known in the Hunt’s theory. A simulation was performed for the cast iron rolls solidifying as if in industrial condition. Since the incubation divides the roll into two zones: C and E; (the first with columnar structure and the second with fully equiaxed structure some experiments dealing with solidification were made on semi-industrial scale.

Eye Allergies

Science.gov (United States)

... Español Eye Health / Eye Health A-Z Eye Allergies Sections What Are Eye Allergies? Eye Allergy Symptoms ... allergy diagnosis Eye allergy treatment What Are Eye Allergies? Leer en Español: ¿Qué son las alergias de ...

The role of water in slip casting

Science.gov (United States)

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

1984-01-01

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

The CAST Time Projection Chamber

CERN Document Server

Autiero, D.; Carmona, J.M.; Cebrian, S.; Chesi, E.; Davenport, M.; Delattre, M.; Di Lella, L.; Formenti, F.; Irastorza, I.G.; Gomez, H.; Hasinoff, M.; Lakic, B.; Luzon, G.; Morales, J.; Musa, L.; Ortiz, A.; Placci, A.; Rodriguez, A.; Ruz, J.; Villar, J.A.; Zioutas, K.

2007-01-01

One of the three X-ray detectors of the CAST experiment searching for solar axions is a Time Projection Chamber (TPC) with a multi-wire proportional counter (MWPC) as a readout structure. Its design has been optimized to provide high sensitivity to the detection of the low intensity X-ray signal expected in the CAST experiment. A low hardware threshold of 0.8 keV is safely set during normal data taking periods, and the overall efficiency for the detection of photons coming from conversion of solar axions is 62 %. Shielding has been installed around the detector, lowering the background level to 4.10 x 10^-5 counts/cm^2/s/keV between 1 and 10 keV. During phase I of the CAST experiment the TPC has provided robust and stable operation, thus contributing with a competitive result to the overall CAST limit on axion-photon coupling and mass.

Heavy steel casting components for power plants 'mega-components' made of high Cr-steels

Energy Technology Data Exchange (ETDEWEB)

Hanus, Reinhold [voestalpine Giesserei Linz GmbH, Linz (Austria)

2010-07-01

Steel castings of creep resistant steels play a key role in fossil fuel fired power plants for highly loaded components in the high and intermediate pressure section of the turbines. Inner and outer casings, valve casings, inlet connections and elbows are examples of such critical components. The most important characteristic in a power plant is the efficiency, which mainly drives the CO2-emission. As a consequence of steadily improving power plant efficiencies and ever stricter emission standards, steam parameters become more critical and the creep resistance of the cast materials must also be constantly improved. The foundries voestalpine Giesserei Linz and voestalpine Giesserei Traisen participated in the development of the new 9-10% Cr-steels for application up to 625 C/650 C and in the THERMIE project where Ni-base alloys for 700 C-power plants were developed. Beside the material development in the European research projects the commercial production had to be established for industrial processes and the newly developed materials have to be transferred from research into the commercial production of heavy cast components. After selecting the most promising alloy from the laboratory melts, welding tests were performed - mostly with matching electrodes also produced within COST/THERMIE. Base material and welds were investigated in respect of microstructure, creep resistance, mechanical properties and weldability. Heat treatment investigations were also necessary for optimization of the mechanical properties. Based on the results of these studies, pilot components and plates for testing welding processes were cast in order to verify the castability and weldability of larger parts and to make any necessary adjustments to chemical composition, heat treatment or welding parameters. Parallel to the ongoing creep tests within COST/THERMIE-program, the newly developed steel grades were introduced into the commercial production of large components. This involved finding

The forty years of vermicular graphite cast iron development in China (PartⅠ

Directory of Open Access Journals (Sweden)

CHEN Zheng-de

2007-05-01

Full Text Available In China, the research and development of vermicular graphite cast iron (VGCI as a new type of engineering material, were started in the same period as in other developed countries; however, its actual industrial application was even earlier. In China, the deep and intensive studies on VGCI began as early as the 1960s. According to the incomplete statistics to date, more than 600 papers on VGCI have been published by Chinese researchers and scholars at national and international conferences, and in technical journals. More than ten types of production methods and more than thirty types of treatment alloy have been studied. Formulae for calculating the critical addition of treatment alloy required to produce VGCI have been put forward, and mechanisms for explaining the formation of dross during treatment were brought forward. The casting properties, metallographic structure, mechanical and physical properties and machining performance of VGCI, as well as the relationships between them, have all been studied in detail. The Chinese Standards for VGCI and VGCI metallographic structure have been issued. In China, the primary crystallization of VGCI has been studied by many researchers and scholars. The properties of VGCI can be improved by heat treatment and addition of alloying elements enabling its applications to be further expanded. Hundreds of kinds of VGCI castings have been produced and used in vehicles, engines, mining equipment, metallurgical products serviced under alternating thermal load, machinery, hydraulic components, textile machine parts and military applications. The heaviest VGCI casting produced is 38 tons and the lightest is only 1 kg. Currently, the annual production of the VGCI in China is about 200 000 tons. The majority of castings are made from cupola iron without pre-treatment, however, they are also produced from electric furnaces and by duplex melting from cupolaelectric furnaces or blast furnace-electric furnace

Improvement of Artistic Cast Production System

Directory of Open Access Journals (Sweden)

Władysiak R.

2017-09-01

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

The X-ray Telescope of CAST

CERN Document Server

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

2007-01-01

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

CASTing light on dark matter particles

CERN Multimedia

2005-01-01

CERN's CAST collaboration recently released first results from its search for solar axions, a candidate dark matter particle. Though they haven't found any axions yet, they have done much to narrow the hunt. The CAST experiment. Physicists think the universe is permeated with dark matter, particles that don't emit or absorb radiation and so are invisible to traditional telescopes. So far no one has found direct signs of dark matter. A different breed of telescope, however, may be able to see such particles. CERN's Axion Solar Telescope (CAST), currently the world's only working axion helioscope, is a superconducting test magnet from the Large Hadron Collider (LHC) that has been refurbished and outfitted with X-ray detectors, plus a focusing mirror system for X-rays that was recovered from the German space program. CAST stares into the sun in search of particles called axions, one of the leading candidates for dark matter. On 9 November, the CAST collaboration released the results of their first experimen...

New progresses of Chinese art casting

Directory of Open Access Journals (Sweden)

Tan Derui

2007-05-01

Full Text Available The Chinese art casting with 5 000 years history has been rapidly developed in recent ten years. This benefits from the great development of Chinese economy, the large-scale urban construction and transformation, the increasing demands for the cultural work of art, the loose religious environment and the expanding international market. The Art Casting Technical Committee of China Foundry Association has been established for 10 years. Almost 90 art casting enterprises joined in the organization, not including nearly thousand enterprises of foreign capital and massive domestic workshop type. It is estimated that the scale and the output of art castings in mainland China have situated the world front row.

Strip casting apparatus and method

Science.gov (United States)

Williams, R.S.; Baker, D.F.

1988-09-20

Strip casting apparatus including a molten-metal-holding container and a nozzle to deposit molten metal onto a moving chill drum to directly cast continuous metallic strip. The nozzle body includes a slot bounded between a back and a front lip. The slot width exceeds about 20 times the gap distance between the nozzle and the chill drum surface. Preferably, the slot width exceeds 0.5 inch. This method of strip casting minimizes pressure drop, insuring better metal-to-chill-drum contact which promotes heat transfer and results in a better quality metallic strip. 6 figs.

Delamination wear mechanism in gray cast irons

International Nuclear Information System (INIS)

Salehi, M.

2000-01-01

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

An Evaluation of ToxCast Angiogenic Disruptors for Effects on Mitochondrial Bioactivity Profiles (Teratology Society Annual Meeting)

Science.gov (United States)

Angiogenesis is a critical developmental process and a potential target for chemical teratogenesis. Over one-tenth of the Tox21 library of 10,000 compounds have been shown to disrupt mitochondrial function [Attene-Ramos et al., 2015]. Previous studies utilizing ToxCast chemicals ...

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

International Nuclear Information System (INIS)

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

2011-01-01

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

Full parallax three-dimensional computer generated hologram with occlusion effect using ray casting technique

International Nuclear Information System (INIS)

Zhang, Hao; Tan, Qiaofeng; Jin, Guofan

2013-01-01

Holographic display is capable of reconstructing the whole optical wave field of a three-dimensional (3D) scene. It is the only one among all the 3D display techniques that can produce all the depth cues. With the development of computing technology and spatial light modulators, computer generated holograms (CGHs) can now be used to produce dynamic 3D images of synthetic objects. Computation holography becomes highly complicated and demanding when it is employed to produce real 3D images. Here we present a novel algorithm for generating a full parallax 3D CGH with occlusion effect, which is an important property of 3D perception, but has often been neglected in fully computed hologram synthesis. The ray casting technique, which is widely used in computer graphics, is introduced to handle the occlusion issue of CGH computation. Horizontally and vertically distributed rays are projected from each hologram sample to the 3D objects to obtain the complex amplitude distribution. The occlusion issue is handled by performing ray casting calculations to all the hologram samples. The proposed algorithm has no restriction on or approximation to the 3D objects, and hence it can produce reconstructed images with correct shading effect and no visible artifacts. Programmable graphics processing unit (GPU) is used to perform parallel calculation. This is made possible because each hologram sample belongs to an independent operation. To demonstrate the performance of our proposed algorithm, an optical experiment is performed to reconstruct the 3D scene by using a phase-only spatial light modulator. We can easily perceive the accommodation cue by focusing our eyes on different depths of the scene and the motion parallax cue with occlusion effect by moving our eyes around. The experiment result confirms that the CGHs produced by our algorithm can successfully reconstruct 3D images with all the depth cues.

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

Science.gov (United States)

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.

Genetic evidence on the origins of Indian caste populations.

Science.gov (United States)

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

Modelling the effect of coating on the stresses and microstructure evolution in chill casting of wind turbine main shafts

DEFF Research Database (Denmark)

Sonne, Mads Rostgaard; Thorborg, J.; Hattel, Jesper Henri

2017-01-01

The purpose of the present work is to quantify the effect of the inside coating on chills for casting of large wind turbine main shafts with respect to the evolution of internal stresses. These are known to affect the lifetime of the chills, and this is a major cost for the foundries today. Simul......, it is concluded that the material quality obtained from casting the main shafts in chills (and hence the performance of the part) is still much better than for sand casting, even though a very thick layer of coating is applied. Copyright © 2017 John Wiley & Sons, Ltd....... in the simulations. The outcome is validated by comparisons with samples taken out from a critical region of main shafts cast in sand and in chills. The results reveal minor reductions in the maximum principal stresses on the inner and outer surfaces of the chill of 3.1% and 18.5%, respectively, from changing...

Microsegregation in Nodular Cast Iron with Carbides

Directory of Open Access Journals (Sweden)

S. Pietrowski

2012-12-01

Full Text Available In this paper results of microsegregation in the newly developed nodular cast iron with carbides are presented. To investigate the pearlitic and bainitic cast iron with carbides obtained by Inmold method were chosen. The distribution of linear elements on the eutectic cell radius was examined. To investigate the microsegregation pearlitic and bainitic cast iron with carbides obtained by Inmold method were chosen.The linear distribution of elements on the eutectic cell radius was examined. Testing of the chemical composition of cast iron metal matrix components, including carbides were carried out. The change of graphitizing and anti-graphitizing element concentrations within eutectic cell was determined. It was found, that in cast iron containing Mo carbides crystallizing after austenite + graphite eutectic are Si enriched.

Microsegregation in Nodular Cast Iron with Carbides

Directory of Open Access Journals (Sweden)

Pietrowski S.

2012-12-01

Full Text Available In this paper results of microsegregation in the newly developed nodular cast iron with carbides are presented. To investigate the pearlitic and bainitic cast iron with carbides obtained by Inmold method were chosen. The distribution of linear elements on the eutectic cell radius was examined. To investigate the microsegregation pearlitic and bainitic cast iron with carbides obtained by Inmold method were chosen. The linear distribution of elements on the eutectic cell radius was examined. Testing of the chemical composition of cast iron metal matrix components, including carbides were carried out. The change of graphitizing and anti-graphitizing element concentrations within eutectic cell was determined. It was found, that in cast iron containing Mo carbides crystallizing after austenite + graphite eutectic are Si enriched.

Simulation of Distortion and Residual Stress Development During Heat Treatment of Steel Castings

Energy Technology Data Exchange (ETDEWEB)

Beckermann, Christoph; Carlson, Kent

2011-07-22

Heat treatment and associated processing, such as quenching, are critical during high strength steel casting production. These processes must be managed closely to prevent thermal and residual stresses that may result in distortion, cracking (particularly after machining), re-work, and weld repair. The risk of casting distortion limits aggressive quenching that can be beneficial to the process and yield an improved outcome. As a result of these distortions, adjustments must be made to the casting or pattern design, or tie bars must be added. Straightening castings after heat treatments can be both time-consuming and expensive. Residual stresses may reduce a casting's overall service performance, possibly resulting in catastrophic failure. Stress relieving may help, but expends additional energy in the process. Casting software is very limited in predicting distortions during heat treatment, so corrective measures most often involve a tedious trial-and-error procedure. An extensive review of existing heat treatment residual stress and distortion modeling revealed that it is vital to predict the phase transformations and microstructure of the steel along with the thermal stress development during heat treatment. After reviewing the state-of-the-art in heat treatment residual stress and distortion modeling, an existing commercial code was selected because of its advanced capabilities in predicting phase transformations, the evolving microstructure and related properties along with thermal stress development during heat treatment. However, this software was developed for small parts created from forgings or machined stock, and not for steel castings. Therefore, its predictive capabilities for heat treatment of steel castings were investigated. Available experimental steel casting heat treatment data was determined to be of insufficient detail and breadth, and so new heat treatment experiments were designed and performed, casting and heat treating modified versions

New progresses of Chinese art casting

OpenAIRE

Tan Derui

2007-01-01

The Chinese art casting with 5 000 years history has been rapidly developed in recent ten years. This benefits from the great development of Chinese economy, the large-scale urban construction and transformation, the increasing demands for the cultural work of art, the loose religious environment and the expanding international market. The Art Casting Technical Committee of China Foundry Association has been established for 10 years. Almost 90 art casting enterprises joined in the organizatio...

Dry Eye

Science.gov (United States)

... Eye » Facts About Dry Eye Listen Facts About Dry Eye Fact Sheet Blurb The National Eye Institute (NEI) ... and their families search for general information about dry eye. An eye care professional who has examined the ...

The CAST time projection chamber

International Nuclear Information System (INIS)

Autiero, D; Beltran, B; Carmona, J M; Cebrian, S; Chesi, E; Davenport, M; Delattre, M; Di Lella, L; Formenti, F; Irastorza, I G; Gomez, H; Hasinoff, M; Lakic, B; Luzon, G; Morales, J; Musa, L; Ortiz, A; Placci, A; Rodrigurez, A; Ruz, J; Villar, J A; Zioutas, K

2007-01-01

One of the three x-ray detectors of the CERN Axion Solar Telescope (CAST) experiment searching for solar axions is a time projection chamber (TPC) with a multi-wire proportional counter (MWPC) as a readout structure. Its design has been optimized to provide high sensitivity to the detection of the low intensity x-ray signal expected in the CAST experiment. A low hardware threshold of 0.8 keV is set to a safe level during normal data taking periods, and the overall efficiency for the detection of photons coming from conversion of solar axions is 62%. Shielding has been installed around the detector, lowering the background level to 4.10 x 10 -5 counts cm -2 s -1 keV -1 between 1 and 10 keV. During phase I of the CAST experiment the TPC has provided robust and stable operation, thus contributing with a competitive result to the overall CAST limit on axion-photon coupling and mass

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

Energy Technology Data Exchange (ETDEWEB)

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

2017-01-04

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

Influence of Modification and Casting Technology on Structure of IN-713C Superalloy Castings

Directory of Open Access Journals (Sweden)

Binczyk F.

2016-09-01

Full Text Available The paper presents the results concerning impact of modification (volume and surface techniques, pouring temperature and mould temperature on stereological parameters of macrostructure in IN713C castings made using post-production scrap. The ability to adjust the grain size is one of the main issues in the manufacturing of different nickel superalloy castings used in aircraft engines. By increasing the grain size one can increase the mechanical properties, like diffusion creep resistance, in higher temperatures. The fine grained castings. on the other hand, have higher mechanical properties in lower temperatures and higher resistance to thermal fatigue. The test moulds used in this study, supplied by Pratt and Whitney Rzeszow, are ordinarily used to cast the samples for tensile stress testing. Volume modification was carried out using the patented filter containing cobalt aluminate. The macrostructure was described using the number of grains per mm2, mean grain surface area and shape index. Obtained results show strong relationship between the modification technique, pouring temperature and grain size. There was no significant impact of mould temperature on macrostructure.

Chemical casting of high-Tc superconducting BiSCCO

International Nuclear Information System (INIS)

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

1989-01-01

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

Development of casting techniques for uranium and uranium alloys

International Nuclear Information System (INIS)

Singh, S.P.

2003-01-01

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

Microstructured metal molds fabricated via investment casting

International Nuclear Information System (INIS)

Cannon, Andrew H; King, William P

2010-01-01

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

Comparing the Structure and Mechanical Properties of Welds on Ductile Cast Iron (700 MPa under Different Heat Treatment Conditions

Directory of Open Access Journals (Sweden)

Ronny M. Gouveia

2018-01-01

Full Text Available The weldability of ductile iron, as widely known, is relatively poor, essentially due to its typical carbon equivalent value. The present study was developed surrounding the heat treatability of welded joints made with a high strength ductile cast iron detaining an ultimate tensile strength of 700 MPa, and aims to determine which heat treatment procedures promote the best results, in terms of microstructure and mechanical properties. These types of alloys are suitable for the automotive industry, as they allow engineers to reduce the thickness of parts while maintaining mechanical strength, decreasing the global weight of vehicles and providing a path for more sustainable development. The results allow us to conclude that heat treatment methodology has a large impact on the mechanical properties of welded joints created from the study material. However, the thermal cycles suffered during welding promote the formation of ledeburite areas near the weld joint. This situation could possibly be dealt through the implementation of post-welding heat treatments (PWHT with specific parameters. In contrast to a ductile cast iron tested in a previous work, the bull-eye ductile cast iron with 700 MPa ultimate tensile strength presented better results during the post-welding heat treatment than during preheating.

Modern Cast Irons in Chemical Engineering

Science.gov (United States)

1934-11-09

fl’ceew. T I SOCIETY OF CHEMICAL INDUSTRY CHEMICAL ENGINEERING GROUP MODERN CAST IRONS IN CHEMICAL ENGINEERING By J. G. PEARCE, M.Sc., F.Inst.P...CAST IRONS IN CHEMICAL ENGINEERING By J. G. PEARCE, M.Sc., F.Inst.P., M.I.E.E.* INTRODUCTION to chemical or thermal resistance. Small blow-holes Any...consideration of modern cast irons in chemical seldom appear to reduce the mechanical strength of engineering should strictly be prefaced by a definition

Selected properties of new „duplex” cast steel

Directory of Open Access Journals (Sweden)

S. Pietrowski

2011-10-01

Full Text Available In this paper selected properties of new „duplex” cast steel are presented. The new cast steel was devised in HYDRO-VACUUM company in Grudziądz, where “duplex” cast steel for pump elements is smelted. The goal was to devise a new grade of “duplex” cast steel of better physicochemical properties and cheaper than now applied. It was demonstrated, that there is the possibility of devising the new grade of “duplex” cast steel. It is characterized by higher mechanical properties, similar wear resistance and greater corrosion resistance in 15% water solution of H2SO4 in comparison to now applied “duplex” cast steel. The chemical composition was selected to obtain in microstructure about of 50% ferrite and 50% austenite. It guarantee the highest properties and the lowest costs of its smelting.In the paper results of: the microstructure, Rm, Rp0,2, A5, HB, wear resistance and corrosion resistance in water solution of 15% HCl and H2SO4 acids of new cast steel was presented. They were compared with now applied in HYDRO-VACUUM company “duplex” cast steel.

Fan Fuel Casting Final Report

Energy Technology Data Exchange (ETDEWEB)

Imhoff, Seth D. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-09-28

LANL was approached to provide material and design guidance for a fan-shaped fuel element. A total of at least three castings were planned. The first casting is a simple billet mold to be made from high carbon DU-10Mo charge material. The second and third castings are for optimization of the actual fuel plate mold. The experimental scope for optimization is only broad enough for a second iteration of the mold design. It is important to note that partway through FY17, this project was cancelled by the sponsor. This report is being written in order to capture the knowledge gained should this project resume at a later date.

The x-ray telescope of CAST

Energy Technology Data Exchange (ETDEWEB)

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

2007-06-15

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

Selfish genetic elements and the gene’s-eye view of evolution

Science.gov (United States)

2016-01-01

During the last few decades, we have seen an explosion in the influx of details about the biology of selfish genetic elements. Ever since the early days of the field, the gene’s-eye view of Richard Dawkins, George Williams, and others, has been instrumental to make sense of new empirical observations and to the generation of new hypotheses. However, the close association between selfish genetic elements and the gene’s-eye view has not been without critics and several other conceptual frameworks have been suggested. In particular, proponents of multilevel selection models have used selfish genetic elements to criticize the gene’s-eye view. In this paper, I first trace the intertwined histories of the study of selfish genetic elements and the gene’s-eye view and then discuss how their association holds up when compared with other proposed frameworks. Next, using examples from transposable elements and the major transitions, I argue that different models highlight separate aspects of the evolution of selfish genetic elements and that the productive way forward is to maintain a plurality of perspectives. Finally, I discuss how the empirical study of selfish genetic elements has implications for other conceptual issues associated with the gene’s-eye view, such as agential thinking, adaptationism, and the role of fitness maximizing models in evolution. PMID:29491953

Casting methods

Science.gov (United States)

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.

Latest results of cast and future prospects

CERN Document Server

Vafeiadis, Theodoros

2014-01-01

CERN Axion Solar Telescope (CAST) is currently the most sensitive axion helioscope designed to search for axions and axion-like particles produced in the Sun. CAST completed successfully the second part of CAST phase II where the magnet bores were lled with 3He gas at variable pressure scanning axion masses up to 1.2 eV In the absence of signal it has set the best experimental limit on the axion-photon coupling constant over a broad range of axion masses. In 2013 CAST has improved its sensitivity to solar axions with rest mass below 0.02 eV by upgrading the Micromegas detectors and it will continue in 2014 with the implementation of a second X-ray optic and a new type detector (InGRID). In addition, CAST has extended its sensitivity into the sub-keV energy range using a silicon detector (SDD), to search for solar chameleons. Thus, CAST also became sensitive to dark energy particles. A new generation axion helioscope (IAXO) aims to improve the current axion-photon coupling by 1-1.5 orders of magnitude. This wi...

design, construction and performance evaluation of multiple casting

African Journals Online (AJOL)

eobe

time taken for solidification, plays an important role in the casting. There should not ... Keywords: Design, Construction, Multiple casting machine, Compo Casting operation. 1. Introduction .... metal and pathway channel pipe with heater is used.

A study of the level of awareness of different Cadre of eye care ...

African Journals Online (AJOL)

Background: The choice of a qualified eye care practitioner, a critical factor in eye care services, pre-supposes that the practitioner has the requisite training and skill. Often, lack of this knowledge among patients, relative overlap of functions among practitioners and attempts occasionally, to assume responsibility, has led to ...

Shadow casted by a Konoplya-Zhidenko rotating non-Kerr black hole

Energy Technology Data Exchange (ETDEWEB)

Wang, Mingzhi; Chen, Songbai; Jing, Jiliang, E-mail: wmz9085@126.com, E-mail: csb3752@hunnu.edu.cn, E-mail: jljing@hunnu.edu.cn [Institute of Physics and Department of Physics, Hunan Normal University, Changsha, Hunan 410081 (China)

2017-10-01

We have investigated the shadow of a Konoplya-Zhidenko rotating non-Kerr black hole with an extra deformation parameter. The spacetime structure arising from the deformed parameter affects sharply the black hole shadow. With the increase of the deformation parameter, the size of the shadow of black hole increase and its shape becomes more rounded for arbitrary rotation parameter. The D-shape shadow of black hole emerges only in the case a <2√3/3\\, M with the proper deformation parameter. Especially, the black hole shadow possesses a cusp shape with small eye lashes in the cases with a >M, and the shadow becomes less cuspidal with the increase of the deformation parameter. Our result show that the presence of the deformation parameter yields a series of significant patterns for the shadow casted by a Konoplya-Zhidenko rotating non-Kerr black hole.

Fast and robust ray casting algorithms for virtual X-ray imaging

International Nuclear Information System (INIS)

Freud, N.; Duvauchelle, P.; Letang, J.M.; Babot, D.

2006-01-01

Deterministic calculations based on ray casting techniques are known as a powerful alternative to the Monte Carlo approach to simulate X- or γ-ray imaging modalities (e.g. digital radiography and computed tomography), whenever computation time is a critical issue. One of the key components, from the viewpoint of computing resource expense, is the algorithm which determines the path length travelled by each ray through complex 3D objects. This issue has given rise to intensive research in the field of 3D rendering (in the visible light domain) during the last decades. The present work proposes algorithmic solutions adapted from state-of-the-art computer graphics to carry out ray casting in X-ray imaging configurations. This work provides an algorithmic basis to simulate direct transmission of X-rays, as well as scattering and secondary emission of radiation. Emphasis is laid on the speed and robustness issues. Computation times are given in a typical case of radiography simulation

Fast and robust ray casting algorithms for virtual X-ray imaging

Energy Technology Data Exchange (ETDEWEB)

Freud, N. [CNDRI, Laboratory of Nondestructive Testing Using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, Avenue Albert Einstein, 69621 Villeurbanne Cedex (France)]. E-mail: Nicolas.Freud@insa-lyon.fr; Duvauchelle, P. [CNDRI, Laboratory of Nondestructive Testing Using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, Avenue Albert Einstein, 69621 Villeurbanne Cedex (France); Letang, J.M. [CNDRI, Laboratory of Nondestructive Testing Using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, Avenue Albert Einstein, 69621 Villeurbanne Cedex (France); Babot, D. [CNDRI, Laboratory of Nondestructive Testing Using Ionizing Radiations, INSA-Lyon Scientific and Technical University, Bat. Antoine de Saint-Exupery, 20, Avenue Albert Einstein, 69621 Villeurbanne Cedex (France)

2006-07-15

Deterministic calculations based on ray casting techniques are known as a powerful alternative to the Monte Carlo approach to simulate X- or {gamma}-ray imaging modalities (e.g. digital radiography and computed tomography), whenever computation time is a critical issue. One of the key components, from the viewpoint of computing resource expense, is the algorithm which determines the path length travelled by each ray through complex 3D objects. This issue has given rise to intensive research in the field of 3D rendering (in the visible light domain) during the last decades. The present work proposes algorithmic solutions adapted from state-of-the-art computer graphics to carry out ray casting in X-ray imaging configurations. This work provides an algorithmic basis to simulate direct transmission of X-rays, as well as scattering and secondary emission of radiation. Emphasis is laid on the speed and robustness issues. Computation times are given in a typical case of radiography simulation.

Nonaqueous slip casting of high temperature ceramic superconductors using an investment casting technique

Science.gov (United States)

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

1993-01-01

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

High quality steel casting for energy technics

International Nuclear Information System (INIS)

Schuster, F.; Koefler, G.

1982-01-01

The casting of several chromium-molybdenum steels for steam and hydraulic turbines is discussed. Non-destructive testing of the castings is performed demonstrating the safety for use in nuclear technology. The effect of metallurgical parameters on steel casting quality, the heat treatment, and the effect of construction design on costs for fettling and repair weldings are considered. (Auth.)

CAST with its micromegas detector installed.

CERN Multimedia

Maximilien Brice

2002-01-01

The CERN Axion Solar Telescope (CAST) uses a prototype LHC dipole magnet to search for very weakly interacting neutral particles called axions, which should originate in the core of the Sun. The magnet converts the solar axions to photons which are then detected by an X-ray detector based on Micromegas technology. CAST's Micromegas detector has now been installed. Photos 01 02: General view of the CAST experiment with the Micromegas detector in place. Photo 03: Close-up of the micromegas set-up.

Research on Soft Reduction Amount Distribution to Eliminate Typical Inter-dendritic Crack in Continuous Casting Slab of X70 Pipeline Steel by Numerical Model

Science.gov (United States)

Liu, Ke; Wang, Chang; Liu, Guo-liang; Ding, Ning; Sun, Qi-song; Tian, Zhi-hong

2017-04-01

To investigate the formation of one kind of typical inter-dendritic crack around triple point region in continuous casting(CC) slab during the operation of soft reduction, fully coupled 3D thermo-mechanical finite element models was developed, also plant trials were carried out in a domestic continuous casting machine. Three possible types of soft reduction amount distribution (SRAD) in the soft reduction region were analyzed. The relationship between the typical inter-dendritic cracks and soft reduction conditions is presented and demonstrated in production practice. Considering the critical strain of internal crack formation, a critical tolerance for the soft reduction amount distribution and related casing parameters have been proposed for better contribution of soft reduction to the internal quality of slabs. The typical inter-dendritic crack around the triple point region had been eliminated effectively through the application of proposed suggestions for continuous casting of X70 pipeline steel in industrial practice.

Energy use in selected metal casting facilities - 2003

Energy Technology Data Exchange (ETDEWEB)

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

2004-05-01

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

Experimental Investigation on Corrosion of Cast Iron Pipes

Directory of Open Access Journals (Sweden)

H. Mohebbi

2011-01-01

Full Text Available It is well known that corrosion is the predominant mechanism for the deterioration of cast iron pipes, leading to the reduction of pipe capacity and ultimate collapse of the pipes. In order to assess the remaining service life of corroded cast iron pipes, it is imperative to understand the mechanisms of corrosion over a long term and to develop models for pipe deterioration. Although many studies have been carried out to determine the corrosion behavior of cast iron, little research has been undertaken to understand how cast iron pipes behave over a longer time scale than hours, days, or weeks. The present paper intends to fill the gap regarding the long-term corrosion behaviour of cast iron pipes in the absence of historical data. In this paper, a comprehensive experimental program is presented in which the corrosion behaviour of three exservice pipes was thoroughly examined in three simulated service environments. It has been found in the paper that localised corrosion is the primary form of corrosion of cast iron water pipes. It has also been found that the microstructure of cast irons is a key factor that affects the corrosion behaviour of cast iron pipes. The paper concludes that long-term tests on corrosion behaviour of cast iron pipes can help develop models for corrosion-induced deterioration of the pipes for use in predicting the remaining service life of the pipes.

Rough case-based reasoning system for continues casting

Science.gov (United States)

Su, Wenbin; Lei, Zhufeng

2018-04-01

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

Method and mold for casting thin metal objects

Science.gov (United States)

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.

Notes of a Racial Caste Baby. Color Blindness and the End of Affirmative Action. Critical America Series.

Science.gov (United States)

Fair, Bryan K.

This book is a defense of remedial affirmative action and an assertion that it is a policy that is a fair and workable solution to the chronic problem of racial caste in the United States. The personal narrative of the author, eighth of 10 children born to a single mother on public assistance, is combined with the discussion of American history…

Caste in 21st Century India: Competing Narratives.

Science.gov (United States)

Desai, Sonalde; Dubey, Amaresh

2012-03-12

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.

Thickness control and interface quality as functions of slurry formulation and casting speed in side-by-side tape casting

DEFF Research Database (Denmark)

Bulatova, Regina; Jabbari, Mirmasoud; Kaiser, Andreas

2014-01-01

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

Education and Caste in India

Science.gov (United States)

Chauhan, Chandra Pal Singh

2008-01-01

This paper analyses the policy of reservation for lower castes in India. This policy is similar to that of affirmative action in the United States. The paper provides a brief overview of the caste system and discusses the types of groups that are eligible for reservation, based on data from government reports. The stance of this paper is that…

Casting materials and their application in research and teaching.

Science.gov (United States)

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

2014-04-01

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

Reengineering of Permanent Mould Casting with Lean Manufacturing Methods

Directory of Open Access Journals (Sweden)

R. Władysiak

2007-07-01

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

Quality improvement of steel cast-welded constructions

Directory of Open Access Journals (Sweden)

Аркадій Васильович Лоза

2017-06-01

Full Text Available Among the various types of metallurgical equipment there are structures which are welded compounds of a cast base and additional elements produced by casting or any other means. Such structures are called cast-welded constructions. Besides new working properties such constructions appear to be more efficient and provide better durability as compared to the similar structures produced by other industrial means. Meanwhile the advantages of the technology are not used in full. One reason is low quality of the compound products caused by lack of proper preparation of the elements to be welded and poor quality of the welds themselves. In the article the methods of quality production and the maintenance of steel cast-welded constructions have been considered. A ladle of a blast-furnace slag car is used as the subject of investigation and further testing of the mentioned above technologies. The ladle is a cast product. Under operating conditions, the ladle undergoes mechanical and thermal load, which results in deformation of its sides that deflect inside. To prevent the deflection stiffening ribs are welded onto the outer surface of the ladle. However, there may be casting defects in the base metal that could reduce the durability of the welds. It has been proved that welds on the unprepared cast base of the steel product cannot guarantee the combination’s durability and reliability. To prevent the influence of the casting defects it has been recommended to cover the base metal with one more metal layer before welding the elements on. Two-layer surfacing provides best result as the first layer serves for the weld penetration of the casting defects since this layer has a significant share of base metal therefore it is less malleable; the second layer is necessary for making the layer viscous enough. The viscous layer ensures the absence of sharp transition from the deposited metal to the base metal and increases the crack resistance of the weld. In

Intraocular lens calculations in atypical eyes

Directory of Open Access Journals (Sweden)

Aazim A Siddiqui

2017-01-01

Full Text Available Cataract surgery is the most performed surgical procedure in the field of ophthalmology. The process of intraocular lens (IOL calculations is a critical step to achieving successful outcomes. Many IOL formulae exist to guide surgeons through the difficult process of picking the most appropriate lens to achieve a certain target refraction. However, these formulae reach within 0.50 diopters of the target refraction only 75% of the time, leaving 25% of the eyes with a significant refractive surprise. A literature review was performed to investigate all the relevant published material on the history, progress, and recent advancements of IOL calculations. Based on this review, the appropriate history, evolution, progress, limitations, and recent advancements are analyzed and explained. Although the modern IOL formulae and biometric devices perform well for average eyes, they are suboptimal for eyes with atypical biometric parameters and also those that are postrefractive and keratoconic. There has not been a single, perfect formula that can resolve the complexities of this process. Various methods of formula optimization and newer generation of IOL formulae and devices may hold the key to improving outcomes in both typical and atypical eyes. These solutions minimize refractive error by introducing new input parameters and complex mathematical techniques to better estimate postoperative lens position.

Cast iron repair method of stitching pin

International Nuclear Information System (INIS)

Yun, In Sik; Yu, Yeong Chul; Kim, Steve S.; Reed, Gary J.

2003-01-01

Many cast iron parts are welded and suffer from improper pre-heating and poor welding skills which destroy the castings due to new cracks, deformations etc. This is due mainly to the lack of understanding of the properties of cast iron. Welding, however impractical, was the only alternative for many years. Locks are used to add strength across a crack. Special drilling jigs are used to create a precise hole pattern that locks are driven into. Our locks have a unique ability to pull the sides of a crack together. Bottom locks are stacked or laminated to a depth of 80% of the casting thickness. Thicker surface locks finish off lock installation, allowing repairs in irregular shapes and contours. Installing products can be done quickly with pneumatic tools. Up to one inch of repair can be done in 5 minutes in 1/4 inch thick cast iron.

Standard digital reference images for titanium castings

CERN Document Server

American Society for Testing and Materials. Philadelphia

2010-01-01

1.1 The digital reference images provided in the adjunct to this standard illustrate various types and degrees of discontinuities occurring in titanium castings. Use of this standard for the specification or grading of castings requires procurement of the adjunct digital reference images, which illustrate the discontinuity types and severity levels. They are intended to provide the following: 1.1.1 A guide enabling recognition of titanium casting discontinuities and their differentiation both as to type and degree through digital radiographic examination. 1.1.2 Example digital radiographic illustrations of discontinuities and a nomenclature for reference in acceptance standards, specifications and drawings. 1.2 The digital reference images consist of seventeen digital files each illustrating eight grades of increasing severity. The files illustrate seven common discontinuity types representing casting sections up to 1-in. (25.4-mm). 1.3 The reference radiographs were developed for casting sections up to 1...

Accuracy of stereolithography additive casts used in a digital workflow

DEFF Research Database (Denmark)

Al-Imam, Hiba; Gram, Mia; Benetti, Ana R

2018-01-01

additive (SLA) casts from 2 manufacturers: 9 Dreve SLA casts and 9 Scanbiz SLA casts. All casts were then scanned 9 times with an extraoral scanner to produce the reference data set. Trueness was evaluated by superimposing the data sets obtained by scanning the casts with the reference data set. Precision...

Spall behavior of cast iron with varying microstructures

International Nuclear Information System (INIS)

Plume, Gifford; Rousseau, Carl-Ernst

2014-01-01

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.

Spall behavior of cast iron with varying microstructures

Energy Technology Data Exchange (ETDEWEB)

Plume, Gifford; Rousseau, Carl-Ernst, E-mail: rousseau@uri.edu [Mechanical Engineering, University of Rhode Island, 92 Upper College Rd., Kingston, Rhode Island 02881 (United States)

2014-07-21

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.

Cast Care: Do's and Don'ts

Science.gov (United States)

... al. Cast care. In: Instructions for Sports Medicine Patients. 2nd ed. Philadelphia, Pa.: Saunders Elsevier; 2012. https://www.clinicalkey.com. Accessed Jan. 25, 2018. Pfenninger JL, et al. Casts immobilization and upper extremity splinting. In: Pfenninger and Fowler's ...

Estimation of integrity of cast-iron cask against impact due to free drop test, (1)

International Nuclear Information System (INIS)

Itoh, Chihiro

1988-01-01

Ductile cast iron is examined to use for shipping and storage cask from a economic point of view. However, ductile cast iron is considered to be a brittle material in general. Therefore, it is very important to estimate the integrity of cast iron cask against brittle failure due to impact load at 9 m drop test and 1 m derop test on to pin. So, the F.E.M. analysis which takes nonlinearity of materials into account and the estimation against brittle failure by the method which is proposed in this report were carried out. From the analysis, it is made clear that critical flaw depth (the minimum depth to initiate the brittle failure) is 21.1 mm and 13.1 mm in the case of 9 m drop test and 1 m drop test on to pin respectively. These flaw depth can be detected by ultrasonic test. Then, the cask is assured against brittle failure due to impact load at 9 m drop test and 1 m drop test on to pin. (author)

Structure Distribution in Precise Cast Iron Moulded on Meltable Model

Directory of Open Access Journals (Sweden)

Skrbek B.

2015-12-01

Full Text Available Topic of this work is to compare metalurgy of cast irons poured into sand moulds and into shell molds at IEG Jihlava company and from it following differencies in structures of thin- and thick-walled castings. This work is dealing with investigation and experimental measurement on surfaces and sections suitable thin- and thick-walled investment castings at IEG Jihlava. Cast irons with flake graphite (grey cast iron and cast irons with spheroidal graphite (ductile cast iron. Both mechanical and physical properties are determined using calculations from as measured values of wall thicknesses L and Lu, Vickers hardness and remanent magnetism. Measurement results are discussed, findings are formulated and methods for castings metallurgical quality improvement are recommended finally.

Metallic Fuel Casting Development and Parameter Optimization Simulations

International Nuclear Information System (INIS)

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

2013-01-01

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

Plane-Casting: 3D Cursor Control with a SmartPhone

OpenAIRE

Katzakis, Nicholas; Kiyokawa, Kiyoshi; Hori, Masahiro; Takemura, Haruo

2018-01-01

We present Plane-Casting, a novel technique for 3D object manipulation from a distance that is especially suitable for smartphones. We describe two variations of Plane-Casting, Pivot and Free Plane-Casting, and present results from a pilot study. Results suggest that Pivot Plane-Casting is more suitable for quick, coarse movements whereas Free Plane-Casting is more suited to slower, precise motion. In a 3D movement task, Pivot Plane-Casting performed better quantitatively, but subjects prefer...

Total contact cast for neuropathic diabetic foot ulcers

International Nuclear Information System (INIS)

Ali, R.; Yaqoob, M.Y.

2008-01-01

To determine the outcome of diabetic neuropathic foot ulcers treated with Total Contact Cast (TCC) in terms of percentage of ulcers healed and time to heal. The study included diabetic patients with non-ischemic neuropathic foot ulcers of upto grade 2 of Wagner's classification. Ulcers were debrided off necrotic tissues and Total Contact Cast (TCC) was applied. TCC was renewed every 2 weeks till healing. Cases were labeled as cast failure when there was no reduction in wound size in 4 consecutive weeks or worsening to a higher grade. Main outcome measures were the percentage of ulcers healed and time to heal in the cast. Thirty four (87.17%) patients were males and 5(12.82%) were females. The mean age was 62 +- 13.05 years. All patients had NIDDM. Out of the 52 ulcers, 41(78.84%) healed with TCC in an average 2 casts duration (mean 32 days). There were 11(21.15%) cast failure. Majority (63.63%) of cast failure ulcers were located on pressure bearing area of heel. Most (90%) of the ulcers on forefoot and midsole region healed with TCC (p<0.001). Longer ulcer duration (mean 57.45 +- 29.64 days) significantly reduced ulcer healing (p<0.001). Total contact cast was an effective treatment modality for neuropathic diabetic foot ulcers of Wagner's grade 2, located on forefoot and midsole region. (author)

Microstructure analysis of cofebsinb metallic glasses with a various geometry prepared by planar flow casting and suction casting methods

International Nuclear Information System (INIS)

Hosko, J.; Janotova, J.; Svec, P.; Matko, I.; Janickovic, D.; Svec, P. Sr.

2012-01-01

In this paper we have studied the structure of as-cast Co_4_7Fe_2_0_._9B_2_1_._2Si_4_._6Nb_6_._3 ribbon, bilayer and bulk samples in form of rods up to 5 mm diameter. Amorphous structure of the ribbons and bilayer prepared by PFC was confirmed by XRD characterization. XRD analysis of the bulk sample with 5 mm diameter indicated the presence of crystalline phases. However, XRD analysis of the bulk sample with 4 mm diameter indicated no significant crystalline peaks. From TEM analysis it was found that in-situ BMG composite was obtained in bulk sample. The edge of bulk sample with 4 mm diameter was fully amorphous, however, the center of this sample contains crystalline particles of micron sizes dispersed in the amorphous matrix. Our results suggest that the system Co_4_7Fe_2_0_._9B_2_1_._2Si_4_._6Nb_6_._3 has high GFA because we have prepared various amorphous materials with different shape and thickness using the techniques of suction casting, modified PFC and PFC. The critical diameter of bulk samples with chemical composition Co_4_7Fe_2_0_._9B_2_1_._2Si_4_._6Nb_6_._3 for emergence amorphous phase is 4 mm. (authors)

NWIS Measurements for uranium metal annular castings

International Nuclear Information System (INIS)

Mattingly, J.K.; Valentine, T.E.; Mihalczo, J.T.

1998-01-01

This report describes measurements performed with annular uranium metal castings of different enrichments to investigate the use of 252 Cf-source-driven noise analysis measurements as a means to quantify the amount of special nuclear material (SNM) in the casting. This work in FY 97 was sponsored by the Oak Ridge Y-12 Plant and the DOE Office of Technology Development Programs. Previous measurements and calculational studies have shown that many of the signatures obtained from the source-driven measurement are very sensitive to fissile mass. Measurements were performed to assess the applicability of this method to standard annular uranium metal castings at the Oak Ridge Y-12 plant under verification by the International Atomic Energy Agency (IAEA) using the Nuclear Weapons Identification System (NWIS) processor. Before the measurements with different enrichments, a limited study of source-detector-casting moderator configurations was performed to enhance the correlated information. These configurations consisted of a casting with no reflector and with various thicknesses of polyethylene reflectors up to 10.16 cm in 2.54 cm steps. The polyethylene moderator thickness of 7.62 cm was used for measurements with castings of different enrichments reported here. The sensitivity of the measured parameters to fissile mass was investigated using four castings each with a different enrichment. The high sensitivity of this measurement method to fissile mass and to other material and configurations provides some advantages over existing safeguards methods

The structure of high-quality aluminium cast iron

Directory of Open Access Journals (Sweden)

D. Kopyciński

2012-01-01

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

Fluid flow and heat transfer modeling for castings

International Nuclear Information System (INIS)

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

1986-01-01

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

Fractomechanical Properties of As-Cast and Austempered SG Cast Iron Between -40 °C and +20 °C

Directory of Open Access Journals (Sweden)

V.E. Fierro

2002-06-01

Full Text Available The spheroidal graphite (SG cast iron fractomechanical response varies with the test temperature and with the microstructure parameters. In the present paper, we analyze this variation performing fractomechanical tests in a temperature range from -40°C to +20°C, doing also Charpy and tensile tests for material characterization. The tests were carried out on as-cast samples and heat treated samples to obtain an ADI grade 1. In both cases, we studied samples taken from two well differentiated "Y" block sizes. The results obtained show that, for the chemical composition analyzed, both castings have a fractomechanical response decrease as the temperature diminishes. Besides, the block size enlargement produce a deterioration of the mechanical properties (the fracture toughness, mainly, for both castings.

CAST Physics Proposal to SPSC

CERN Document Server

CAST, Collaboration

2011-01-01

The CAST experiment has the potential to search for solar axions (dark matter particle candidates) or other particles with similar coupling. E.g., paraphtons (Hidden Sector), chameleons (dark energy), while considering the possibility whether CAST could be transformed to an antenna for relic axions with rest mass up to 0.1 to 1meV. While axion searches suggest detectors with lower background, paraphoton and chameleon searches require detectors with sub-keV threshold energy and the use of transparent windows in front of the Micromegas detectors, which cover 3 out of the 4 CAST magnet exits. Ongoing theoretical estimates and experimental investigations will define the priorities of the suggested 4 physics items of this proposal for the period 2012-2014.

Cast Metals Coalition Technology Transfer and Program Management Final Report

Energy Technology Data Exchange (ETDEWEB)

Gwyn, Mike

2009-03-31

The Cast Metals Coalition (CMC) partnership program was funded to ensure that the results of the Department of Energy's (DOE) metalcasting research and development (R&D) projects are successfully deployed into industry. Specifically, the CMC program coordinated the transfer and deployment of energy saving technologies and process improvements developed under separately funded DOE programs and projects into industry. The transition of these technologies and process improvements is a critical step in the path to realizing actual energy savings. At full deployment, DOE funded metalcasting R&D results are projected to save 55% of the energy used by the industry in 1998. This closely aligns with DOE's current goal of driving a 25% reduction in industrial energy intensity by 2017. In addition to benefiting DOE, these energy savings provide metalcasters with a significant economic advantage. Deployment of already completed R&D project results and those still underway is estimated to return over 500% of the original DOE and industry investment. Energy savings estimates through December 2008 from the Energy-Saving Melting and Revert Reduction Technology (E-SMARRT) portfolio of projects alone are 12 x 1012 BTUs, with a projection of over 50 x 1012 BTUs ten years after program completion. These energy savings and process improvements have been made possible through the unique collaborative structure of the CMC partnership. The CMC team consists of DOE's Office of Industrial Technology, the three leading metalcasting technical societies in the U.S: the American Foundry Society; the North American Die Casting Association; and the Steel Founders Society of America; and the Advanced Technology Institute (ATI), a recognized leader in distributed technology management. CMC provides collaborative leadership to a complex industry composed of approximately 2,100 companies, 80% of which employ less than 100 people, and only 4% of which employ more than 250 people

INDIAN CASTE SYSTEM: HISTORICAL AND PSYCHOANALYTIC VIEWS.

Science.gov (United States)

Vallabhaneni, Madhusudana Rao

2015-12-01

This paper elucidates the historical origins and transformations of India's caste system. Surveying the complex developments over many centuries, it points out that three positions have been taken in this regard. One suggests that the caste one is born into can be transcended within one's lifetime by performing good deeds. The other declares caste to be immutable forever. And, the third says that one can be reborn into a higher caste if one lives a virtuous life. Moving on to the sociopolitical realm, the paper notes how these positions have been used and exploited. The paper then attempts to anchor the existence and purpose of the Hindu caste system in Freud's ideas about group psychology and Klein's proposals of splitting and projective identification. The paper also deploys the large group psychology concepts of Volkan and the culturally nuanced psychoanalytic anthropology of Roland and Kakar. It concludes with delineating some ameliorative strategies for this tragic problem in the otherwise robust democratic society of India.

Colour Metallography of Cast Iron - Chapter 1: Introduction (Ⅰ

Directory of Open Access Journals (Sweden)

Zhou Jiyang

2009-02-01

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

Beryllium-aluminum alloys for investment castings

International Nuclear Information System (INIS)

Nachtrab, W.T.; Levoy, N.

1997-01-01

Beryllium-aluminum alloys containing greater than 60 wt % beryllium are very favorable materials for applications requiring light weight and high stiffness. However, when produced by traditional powder metallurgical methods, these alloys are expensive and have limited applications. To reduce the cost of making beryllium-aluminum components, Nuclear Metals Inc. (NMI) and Lockheed Martin Electronics and Missiles have recently developed a family of patented beryllium-aluminum alloys that can be investment cast. Designated Beralcast, the alloys can achieve substantial weight savings because of their high specific strength and stiffness. In some cases, weight has been reduced by up to 50% over aluminum investment casting. Beralcast is now being used to make thin wall precision investment castings for several advanced aerospace applications, such as the RAH-66 Comanche helicopter and F-22 jet fighter. This article discusses alloy compositions, properties, casting method, and the effects of cobalt additions on strength

A dynamic control water distribution model of steel in continuous casting

International Nuclear Information System (INIS)

Fu Jianxun; Hwang, Weng-Sing; Tsai, De-Chang; Tsai, Ming Hsiu; Wang, Chien-Hsun

2012-01-01

After investigation in many continuous casting shop of steel, a dynamic water distribution model is proposed for flexible control on secondary cooling in continuous casting. In this model, the water cooling intensity is determined by the model casting speed instead of the real casting speed. When the casting speed is steady, the model casting speed is equal to the real casting speed. When the real casting speed is changing, the model casting speed according to calculating algorithm to adjust and approaches to the real one, but there is a time delay between them, so it can avoid the slab surface temperature fluctuated due to casting speed changes. The secondary cooling can be dynamically controlled by monitoring the model casting speed. The compare of the simulation results and the measured results reveals that the temperature field and thickness of slab shell in simulations agree very well with the real production situations.

Manufacturing technology of high-quality pressure castings

Directory of Open Access Journals (Sweden)

S. Pietrowski

2011-10-01

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

Application of digital pattern-less molding technology to produce art casting

Directory of Open Access Journals (Sweden)

Chen Li1

2014-11-01

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

Economical surface treatment of die casting dies to prevent soldering in high pressure casting

International Nuclear Information System (INIS)

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

2001-01-01

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

Shrinkages in heavy-sized cast components of nodular cast iron – NDT and fatigue

Directory of Open Access Journals (Sweden)

Bleicher Christoph

2014-06-01

Full Text Available Material defects like shrinkages, dross, pores and chunky graphite are likely to occur in thick-walled castings and are a challenge for the foundries and their customers. These defects are mostly detected with handheld ultrasonic testing (UT or X-ray analysis. Within a research project done at the Fraunhofer Institute for Structural Durability and System Reliability LBF, the fatigue of Dross, shrinkages and chunky graphite in thick-walled cast material GGG-40 was estimated based on X-ray and fatigue tests on bending specimens. High fatigue reductions were received for the different material imperfections. Based on these impressions a further research project was executed at the Fraunhofer LBF to get an estimation of the informational value of UT in relation to fatigue of shrinkages in thick-walled castings of the material EN-GJS-400-18U-LT, EN-GJS-450-18 and EN-GJS-700-2. With the help of X-ray analysis and the UT technique Sampling Phased Array (SPA information about geometry and density were derived for a numerical analysis of shrinkages in thick-walled castings concerning fatigue. The following text summarizes the fatigue results achieved in the two research projects with the help of the X-ray and UT analysis.

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

Science.gov (United States)

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.

Reinforcement of Aluminum Castings with Dissimilar Metals

Energy Technology Data Exchange (ETDEWEB)

Han, Q

2004-01-07

The project ''Reinforcement of Aluminum Casting with Dissimilar Metal'' was a Cooperative Research and Development Agreements (CRADAs) between Oak Ridge National Laboratory (ORNL) and Cummins Inc. This project, technologies have been developed to reinforce aluminum castings with steel insert. Defect-free bond between the steel insert and the aluminum casting has been consistently obtained. The push-out experiment indicated that the bond strength is higher than that of the Al-Fin method. Two patents have been granted to the project team that is comprised of Cummins Inc. and ORNL. This report contains four sections: the coating of the steel pins, the cast-in method, microstructure characterization, and the bond strength. The section of the coating of the steel pins contains coating material selection, electro-plating technique for plating Cu and Ni on steel, and diffusion bonding of the coatings to the steel. The section of cast-in method deals with factors that affecting the quality of the metallurgical bond between the coated steel and the aluminum castings. The results of microstructure characteristics of the bonding are presented in the microstructure characterization section. A push-out experiment and the results obtained using this method is described in the section of bond strength/mechanical property.

Radiology reading-caused fatigue and measurement of eye strain with critical flicker fusion frequency

International Nuclear Information System (INIS)

Maeda, Eriko; Yoshikawa, Takeharu; Hayashi, Naoto; Akai, Hiroyuki; Hanaoka, Shouhei; Sasaki, Hiroki; Matsuda, Izuru; Yoshioka, Naoki; Ohtomo, Kuni

2011-01-01

The aim of this study was to investigate eye fatigue that could impair diagnostic accuracy by measuring the critical flicker fusion frequency (CFFF) before and after reading. CFFF was measured before and after about 4 h of health checkup reading in seven healthy volunteer radiologists. A questionnaire was also completed on duration of sleep the night before the experiment, average duration of sleep, and subjective fatigue using a visual analog scale (corrected to a 0-1 scale, 0 indicating the worst fatigue ever experienced). After-reading subjective fatigue was significantly greater (before 0.52±0.15, after 0.42±0.15), and CFFF was significantly lower (before 40.9±2.4, after 39.9±2.0). There was no significant correlation between subjective fatigue and CFFF, either before or after or between before- and after-reading differences in subjective fatigue and CFFF. Shorter duration of sleep the night before significantly correlated with lower CFFF (Pearson's correlation coefficient): before 0.42, P=0.0047; after 0.52, P=0.0003. CFFF declines after reading and can be considered useful as an indicator of fatigue induced by radiology reading. CFFF declines significantly when sleep is reduced the day before reading without correlation with subjective fatigue, meaning that sleep deprivation can cause an unaware decline in visual function. (author)

Casting of Titanium and its Alloys

OpenAIRE

R. L. Saha; K. T. Jacob

1986-01-01

Titaniuni and its alloys have many applications in aerospace, marine and other engineering industries. Titanium requires special melting techniques because of its high reactivity at elevated temperatures and needs special mould materials and methods for castings. This paper reviews the development of titanium casting technology.

Interface Structure and Elements Diffusion of As-Cast and Annealed Ductile Iron/Stainless Steel Bimetal Castings

Directory of Open Access Journals (Sweden)

M. Ramadan

2018-04-01

Full Text Available Bimetal casting is considered to a promising technique for the production of high performance function materials. Heat treatment process for bimetal castings became an essential tool for improving interface structure and metallurgical diffusion bond. Molten iron alloy with carbon equivalent of 4.40 is poured into sand mold cavities containing solid 304 stainless steel strips insert. Specimens are heated to 7200C in an electrical heating furnace and holded at 720 0C for 60min and 180min. For as-cast specimens, a good coherent interface structure of ductile cast iron/304 stainless bimetal with four layers interfacial microstructure are obtained. Low temperature annealing at 720oC has a significat effect on the interface layers structure, where, three layers of interface structure are obtained after 180min annealing time because of the complete dissolving of thin layer of ferrite and multi carbides (Layer 2. Low temperature annealing shows a significant effect on the diffusion of C and otherwise shows slightly effect on the diffusion of Cr and Ni. Plearlite phase of Layer 3 is trsformed to spheroidal shape instead of lamallar shape in as-cast bimetals by low tempeature annealing at 720oC. The percent of the performed spheroidal cementit increases by increasing anneaaling time. Hardness of interface layers is changed by low temperauture annealing due to the significant carbon deffussion.

Perspectives of single cast nanowires technology

International Nuclear Information System (INIS)

Ioisher, Anatolii; Badinter, Efim; Postolache, Vitalie; Leporda, Nicolae; Tiginyanu, Ion; Monaico, Eduard

2011-01-01

The paper is dedicated to production potential of glass-coated cast nanowire with metal-, semimetal- and semiconductor-based cores by means of Taylor-Ulitovsky method. Criteria of melted core-formative material penetration into a drawing capillary were analyzed. Theoretical preconditions of the reduction of cast microwire diameter up to nano-dimensions of core are reviewed and an improved method of cast nanowire manufacturing is proposed. Correctness of conclusions was experimentally proved and laboratory samples of micro- and nano-wires with core diameter of about 200-300 nanometers were produced, even in case of materials with poor adhesion.

Caste dominance and economic performance in rural India

NARCIS (Netherlands)

Kalwij, Adriaan; Iversen, Vegard; Verschoor, Arjan; Dubey, Amaresh

2014-01-01

Using household panel data for rural India covering 1993–94 and 2004–5, we test whether scheduled castes (SCs) and other minority groups perform better or worse in terms of income when resident in villages dominated by (i) upper castes or (ii) their own group. Theoretically, upper-caste dominance

Spatial constancy of attention across eye movements is mediated by the presence of visual objects.

Science.gov (United States)

Lisi, Matteo; Cavanagh, Patrick; Zorzi, Marco

2015-05-01

Recent studies have shown that attentional facilitation lingers at the retinotopic coordinates of a previously attended position after an eye movement. These results are intriguing, because the retinotopic location becomes behaviorally irrelevant once the eyes have moved. Critically, in these studies participants were asked to maintain attention on a blank location of the screen. In the present study, we examined whether the continuing presence of a visual object at the cued location could affect the allocation of attention across eye movements. We used a trans-saccadic cueing paradigm in which the relevant positions could be defined or not by visual objects (simple square outlines). We find an attentional benefit at the spatiotopic location of the cue only when the object (the placeholder) has been continuously present at that location. We conclude that the presence of an object at the attended location is a critical factor for the maintenance of spatial constancy of attention across eye movements, a finding that helps to reconcile previous conflicting results.

Complicating Eroticism and the Male Gaze: Feminism and Georges Bataille’s Story of the Eye

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Chris Vanderwees

2014-01-01

Full Text Available This article explores the relationship between feminist criticism and Georges Bataille’s Story of the Eye . Much of the critical work on Bataille assimilates his psychosocial theories in Erotism with the manifestation of those theories in his fiction without acknowledging potential contradictions between the two bodies of work. The conflation of important distinctions between representations of sex and death in Story of the Eye and the writings of Erotism forecloses the possibility of reading Bataille’s novel as a critique of gender relations. This article unravels some of the distinctions between Erotism and Story of the Eye in order to complicate the assumption that the novel simply reproduces phallogocentric sexual fantasies of transgression. Drawing from the work of Angela Carter and Laura Mulvey, the author proposes the possibility of reading Story of the Eye as a pornographic critique of gender relations through an analysis of the novel’s displacement and destruction of the male gaze.

A Casting Yield Optimization Case Study: Forging Ram

DEFF Research Database (Denmark)

Kotas, Petr; Tutum, Cem Celal; Hattel, Jesper Henri

2010-01-01

This work summarizes the findings of multi-objective optimization of a gravity sand-cast steel part for which an increase of the casting yield via riser optimization was considered. This was accomplished by coupling a casting simulation software package with an optimization module. The benefits...... of this approach, recently adopted in foundry industry world wide and based on fully automated computer optimization, were demonstrated. First, analyses of filling and solidification of the original casting design were conducted in the standard simulation environment to determine potential flaws and inadequacies...

Independent origins of Indian caste and tribal paternal lineages.

Science.gov (United States)

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.

Did Language Evolve Like the Vertebrate Eye?

Science.gov (United States)

Botha, Rudolf P.

2002-01-01

Offers a critical appraisal of the way in which the idea that human language or some of its features evolved like the vertebrate eye by natural selection is articulated in Pinker and Bloom's (1990) selectionist account of language evolution. Argues that this account is less than insightful because it fails to draw some of the conceptual…

Fiber laser cladding of nickel-based alloy on cast iron

Energy Technology Data Exchange (ETDEWEB)

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

2016-06-30

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

Review of the continuous casting of steel by strip casting technology. Twin roll method system

International Nuclear Information System (INIS)

Ibarrondo, I.

2008-01-01

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

Precision casting into disposable ceramic mold – a high efficiency method of production of castings of irregular shape

OpenAIRE

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

2016-01-01

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

Evaluation and Characterization of In-Line Annealed Continuous Cast Aluminum Sheet

Energy Technology Data Exchange (ETDEWEB)

Dr Subodh K. Das

2006-01-17

This R&D program will develop optimized, energy-efficient thermo-mechanical processing procedures for in-line annealing of continuously cast hot bands of two 5000 series aluminum alloys (5754 and 5052). The implementation of the R&D will result in the production of sheet with improved formability at high levels of productivity consistency and quality. The proposed R&D involves the following efforts: (1) Design and build continuous in-line annealing equipment for plant-scale trials; (2) Carry out plant-scale trials at Commonwealth Aluminum Corp.'s (CAC) plant in Carson; (3) Optimize the processing variables utilizing a metallurgical model for the kinetics of microstructure and texture evolution during thermo-mechanical processing; (4) Determine the effects of processing variables on the microstructure, texture, mechanical properties, and formability of aluminum sheet; (5) Develop design parameters for commercial implementation; and (6) Conduct techno-economic studies of the recommended process equipment to identify impacts on production costs. The research and development is appropriate for the domestic industry as it will result in improved aluminum processing capabilities and thus lead to greater application of aluminum in various industries including the automotive market. A teaming approach is critical to the success of this effort as no single company alone possesses the breadth of technical and financial resources for successfully carrying out the effort. This program will enable more energy efficient aluminum sheet production technology, produce consistent high quality product, and have The proposal addresses the needs of the aluminum industry as stated in the aluminum industry roadmap by developing new and improved aluminum processes utilizing energy efficient techniques. The effort is primarily related to the subsection on Rolling and Extrusion with the R&D to address energy and environmental efficiencies in aluminum manufacturing and will provide

Clean Cast Steel Technology - Machinability and Technology Transfer

Energy Technology Data Exchange (ETDEWEB)

C. E. Bates; J. A. Griffin

2000-05-01

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

An attempt of assessing the production perspectives concerning malleable iron castings

Directory of Open Access Journals (Sweden)

M.S. Soiński

2009-07-01

Full Text Available The paper presents a historical outline of production of the malleable cast iron castings on the territory of Poland during the past over a hundred years. There have been also gathered data concerning the total quantity of castings and the quantity of malleable iron and nodular iron castings produced in twelve selected countries over the period from 1993 to 2006. The percentage of malleable iron to total production of castings, and for a purpose of comparison the percentage of nodular cast iron to total production of castings, has been determined for these countries. A distinct decreasing tendency can be seen with respect to the production of malleable iron castings, while an increasing trend exists in production of nodular iron castings.

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

Science.gov (United States)

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.

Microstructural evolution and mechanical properties of as-cast and T6-treated AA2195 DC cast alloy

International Nuclear Information System (INIS)

Hekmat-Ardakan, A.; Elgallad, E.M.; Ajersch, F.; Chen, X.-G.

2012-01-01

The use of direct chill (DC) cast ingot plates of AA2195 alloys has been recently extended for large mold applications in the plastics and automotive industries. The microstructural evolution of the as-cast AA2195 alloy was investigated using the Factsage thermodynamic software under both equilibrium and non-equilibrium conditions, and was compared with the results from differential scanning calorimetry (DSC) analysis and microstructural observations. The as-cast microstructure exhibited the presence of Al 2 CuMg, Al 2 Cu and Al 2 CuLi intermetallic phases formed at the aluminum dendrite boundaries, which can be completely dissolved in the α-Al matrix during the solution treatment. A significant improvement in the mechanical properties of the AA2195 cast alloy after the T6 heat treatment is attributed to the formation of nano-scale θ′ (Al 2 Cu) and T1 (Al 2 CuLi) precipitates. However, the non-uniform distribution of T1 precipitates together with the large size and low density indicate that the role of θ′ precipitates in strengthening the AA2195 cast alloy is more dominant than that of the T1 precipitates, in contrast with the strengthening mechanism of the pre-deformed AA2195-T8 rolled products.

Eye Protection

OpenAIRE

Pashby, Tom

1986-01-01

Eye injuries frequently occur in the home, at work and at play. Many result in legally blind eyes, and most are preventable. Awareness of potential hazards is essential to preventing eye injuries, particularly in children. In addition, protective devices must be used appropriately. We have developed eye protectors that have proved effective in reducing both the overall incidence and the severity of sports eye injuries.

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

Energy Technology Data Exchange (ETDEWEB)

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

2004-04-29

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

Understanding sexual violence as a form of caste violence

Directory of Open Access Journals (Sweden)

Prachi Patil

2016-07-01

Full Text Available The paper attempts to understand narratives of sexual violence anchored within the dynamics of social location of caste and gender. Apparent caste-patriarchy and gender hierarchies which are at play in cases of sexual violence against lower-caste and dalit women speak about differential experiences of rape and sexual abuse that women have in India. The paper endeavours to establish that sexual violence is also a form of caste violence by rereading the unfortunate cases of Bhanwari Devi, Khairlanji, Lalasa Devi and Delta Meghwal Keywords: caste-patriarchy, Dalit women, POA Act, rape, sexual violence

Diabetes eye exams

Science.gov (United States)

Diabetic retinopathy - eye exams; Diabetes - eye exams; Glaucoma - diabetic eye exam; Macular edema - diabetic eye exam ... if the doctor who takes care of your diabetes checks your eyes, you need an eye exam ...

Directional asymmetries in human smooth pursuit eye movements.

Science.gov (United States)

Ke, Sally R; Lam, Jessica; Pai, Dinesh K; Spering, Miriam

2013-06-27

Humans make smooth pursuit eye movements to bring the image of a moving object onto the fovea. Although pursuit accuracy is critical to prevent motion blur, the eye often falls behind the target. Previous studies suggest that pursuit accuracy differs between motion directions. Here, we systematically assess asymmetries in smooth pursuit. In experiment 1, binocular eye movements were recorded while observers (n = 20) tracked a small spot of light moving along one of four cardinal or diagonal axes across a featureless background. We analyzed pursuit latency, acceleration, peak velocity, gain, and catch-up saccade latency, number, and amplitude. In experiment 2 (n = 22), we examined the effects of spatial location and constrained stimulus motion within the upper or lower visual field. Pursuit was significantly faster (higher acceleration, peak velocity, and gain) and smoother (fewer and later catch-up saccades) in response to downward versus upward motion in both the upper and the lower visual fields. Pursuit was also more accurate and smoother in response to horizontal versus vertical motion. CONCLUSIONS. Our study is the first to report a consistent up-down asymmetry in human adults, regardless of visual field. Our findings suggest that pursuit asymmetries are adaptive responses to the requirements of the visual context: preferred motion directions (horizontal and downward) are more critical to our survival than nonpreferred ones.

Theory of uniqueness of Indian Caste System

OpenAIRE

Ashwin Kumar

2006-01-01

Classical studies on pre-modern Indian social structure have suggested apparent differences between the Indian caste system and social stratification as one can discern in other parts of the world. However, one needs to question such dogmatic assertions that such vast differences really existed. An endeavor is made in this research paper to reflect on the nature of caste hierarchy in pre-modern India. The caste system forms the significant basis of pre-modern Indian social structure. Early wr...

46 CFR 153.239 - Use of cast iron.

Science.gov (United States)

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...

Centrifugal vacuum casting for fuel cladding tube blanks

International Nuclear Information System (INIS)

Zelenskii, V.F.; Neklyudov, I.M.; Chernyi, B.P.; Zeidlits, M.P.; Vanzha, A.F.; Rubashko, V.G.; Ryabchikov, L.N.; Smirnov, Y.K.; Bespalova, V.R.; Mashkarova, V.T.; Rybal'chenko, N.D.

1990-01-01

An advanced technique for making tube blanks with an acceptable level of nonmetallic inclusions is vacuum induction melting combined with centrifugal casting, as the latter gives a cylindrical casting having an axial hole, while the cast metal has elevated density and contains fewer nonmetallic inclusions than does the metal cast in a stationary mold. The reduction in the nonmetallic inclusions occurs because of increased rates of floating up in the rotating mold on account of the centrifugal force and the rejection to the inner surface. One can choose the parameters such as the pouring speed, rotational speed, mold cooling, and liquid-metal temperature and can introduce a deoxidizer to remove the nonmetallic inclusions or reduce the grain size of them and produce an appropriate cast structure and obtain a metal whose quality is the same as that on vacuum induction melting with secondary arc remelting. For these purposes, the authors have developed centrifugal-casting machines for use under vacuum or in inert gases with horizontal and vertical mold rotation axes

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

Science.gov (United States)

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

PRECISION CASTING INTO DISPOSABLE CERAMIC MOLD – A HIGH EFFICIENCY METHOD OF PRODUCTION OF CASTINGS OF IRREGULAR SHAPE

Directory of Open Access Journals (Sweden)

B. I. Uvarov

2016-01-01

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

Effect of molybdenum, vanadium, boron on mechanical properties of high chromium white cast iron in as-cast condition

Science.gov (United States)

Nurjaman, F.; Sumardi, S.; Shofi, A.; Aryati, M.; Suharno, B.

2016-02-01

In this experiment, the effect of the addition carbide forming elements on high chromium white cast iron, such as molybdenum, vanadium and boron on its mechanical properties and microstructure was investigated. The high chromium white cast iron was produced by casting process and formed in 50 mm size of grinding balls with several compositions. Characterization of these grinding balls was conducted by using some testing methods, such as: chemical and microstructure analysis, hardness, and impact test. From the results, the addition of molybdenum, vanadium, and boron on high chromium white cast iron provided a significant improvement on its hardness, but reduced its toughness. Molybdenum induced fully austenitic matrix and Mo2C formation among eutectic M7C3 carbide. Vanadium was dissolved in the matrix and carbide. While boron was played a role to form fine eutectic carbide. Grinding balls with 1.89 C-13.1 Cr-1.32 Mo-1.36 V-0.00051 B in as-cast condition had the highest hardness, which was caused by finer structure of eutectic carbide, needle like structure (upper bainite) matrix, and martensite on its carbide boundary.

Eye Absence Does Not Regulate Planarian Stem Cells during Eye Regeneration.

Science.gov (United States)

LoCascio, Samuel A; Lapan, Sylvain W; Reddien, Peter W

2017-02-27

Dividing cells called neoblasts contain pluripotent stem cells and drive planarian flatworm regeneration from diverse injuries. A long-standing question is whether neoblasts directly sense and respond to the identity of missing tissues during regeneration. We used the eye to investigate this question. Surprisingly, eye removal was neither sufficient nor necessary for neoblasts to increase eye progenitor production. Neoblasts normally increase eye progenitor production following decapitation, facilitating regeneration. Eye removal alone, however, did not induce this response. Eye regeneration following eye-specific resection resulted from homeostatic rates of eye progenitor production and less cell death in the regenerating eye. Conversely, large head injuries that left eyes intact increased eye progenitor production. Large injuries also non-specifically increased progenitor production for multiple uninjured tissues. We propose a model for eye regeneration in which eye tissue production by planarian stem cells is not directly regulated by the absence of the eye itself. Copyright © 2017 Elsevier Inc. All rights reserved.

Filter effectiveness in the manufacture of high-chromium steel castings

Directory of Open Access Journals (Sweden)

M. Garbiak

2011-01-01

Full Text Available The paper presents the results of studies on the application of ceramic filters in the manufacture of cast hearth plates at the WestPomeranian University of Technology in Szczecin. Castings were poured from the heat-resistant G-X40CrNiSi27-4 cast steel in greensand moulds. The development of casting manufacturing technology included the following studies: analysis of the causes of nonmetallicinclusions in high-chromium alloys, computer simulation of mould filling with liquid metal using standard gating systems without filters and new systems with the built-in filter, making pilot castings, quantitative determination of the content of non-metallicinclusions, determination of the oxygen and nitrogen content, and evaluation of the extent of occurrence of the raw casting s urfacedefects. As a result of the conducted studies and analyses, the quality of produced castings was improved, mainly through the reducedcontent of non-metallic inclusions and better raw casting surface quality.

Casting dimensional control and fatigue life prediction for permanent mold casting dies. Technical progress report, September 29, 1993-- September 30, 1994

Energy Technology Data Exchange (ETDEWEB)

NONE

1994-11-01

First year efforts as part of a three year program to address metal casting dimensional control and fatigue life prediction for permanent mold casting dies are described. Procedures have been developed and implemented to collect dimensional variability data from production steel castings. The influence of process variation and casting geometry variables on dimensional tolerances have been investigated. Preliminary results have shown that these factors have a significant influence on dimensional variability, although this variability is considerably less than the variability indicated in current tolerance standards. Gage repeatability and reproducibility testing must precede dimensional studies to insure that measurement system errors are acceptably small. Also initial efforts leading to the development and validation of a CAD/CAE model to predict the thermal fatigue life of permanent molds for aluminum castings are described. An appropriate thermomechanical property database for metal, mold and coating materials has been constructed. A finite element model has been developed to simulate the mold temperature distribution during repeated casting cycles. Initial validation trials have indicated the validity of the temperature distribution model developed.

Assessment of Systems for Mechanisation of Casting Production

Directory of Open Access Journals (Sweden)

A. Fedoryszyn

2007-07-01

Full Text Available Using data on the world production of castings, the situation of foundry industry in Poland was evaluated with emphasis put on the produc-tivity of domestic foundries. It has been observed that an increase of productivity requires a wide-scale mechanisation of the equipment used for casting production on modern foundry moulding lines. Modernisation of foundries is expected to help in creation of optimum conditions for casting production, satisfying all the requirements regarding quantity and quality of castings produced. Modern designs of moulding lines were described, including moulding machines and the related equipment.

Casting defects and fatigue behaviour of ductile cast iron for wind turbine components: A comprehensive study

Energy Technology Data Exchange (ETDEWEB)

Haerkegaard, G. [Norwegian University of Science and Technology, Dept. of Engineering Design and Materials, Trondheim (Norway); Shirani, M.

2011-12-15

Two types of EN-GJS-400-18-LT ductile cast iron were investigated in this research, clean baseline material in the shape of castings with different thicknesses and also defective material from a rejected wind turbine hub. P-S-N curves for baseline EN-GJS-400-18-LT specimens with different dimensions and from castings with different thicknesses at different load ratios were established. Geometrical size effect, technological size effects and mean stress effect on fatigue strength of baseline EN-GJS-400-18-LT were evaluated. Fatigue strength of baseline EN-GJS-400-18-LT was compared with that of defective material from the rejected hub. The effect of defects type, shape, size and position on fatigue strength of this material was evaluated. The hypothesis that the endurance observed in an S-N test can be predicted based on the analysis of crack growth from casting defects through defect-free 'base' material was tested for the analyzed defective material. 3D X-ray computed tomography was use to detect defects in defective specimens and find the defect size distribution. The obtained defect size distribution for the defective material was used in random defect analysis to establish the scatter of fatigue life for defective specimens. Finally both safe-life design and damage tolerant design of wind turbine castings were analyzed and compared. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Evaluation of cast creep occurring during simulated clubfoot correction.

Science.gov (United States)

Cohen, Tamara L; Altiok, Haluk; Wang, Mei; McGrady, Linda M; Krzak, Joseph; Graf, Adam; Tarima, Sergey; Smith, Peter A; Harris, Gerald F

2013-08-01

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 creep displacement occurred in the plaster of Paris (2.0°), then the semi-rigid fiberglass (1.0°), and then the rigid fiberglass (0.4°). 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.

Heat Transfer Coefficient at Cast-Mold Interface During Centrifugal Casting: Calculation of Air Gap

Science.gov (United States)

Bohacek, Jan; Kharicha, Abdellah; Ludwig, Andreas; Wu, Menghuai; Karimi-Sibaki, Ebrahim

2018-06-01

During centrifugal casting, the thermal resistance at the cast-mold interface represents a main blockage mechanism for heat transfer. In addition to the refractory coating, an air gap begins to form due to the shrinkage of the casting and the mold expansion, under the continuous influence of strong centrifugal forces. Here, the heat transfer coefficient at the cast-mold interface h has been determined from calculations of the air gap thickness d a based on a plane stress model taking into account thermoelastic stresses, centrifugal forces, plastic deformations, and a temperature-dependent Young's modulus. The numerical approach proposed here is rather novel and tries to offer an alternative to the empirical formulas usually used in numerical simulations for a description of a time-dependent heat transfer coefficient h. Several numerical tests were performed for different coating thicknesses d C, rotation rates Ω, and temperatures of solidus T sol. Results demonstrated that the scenario at the interface is unique for each set of parameters, hindering the possibility of employing empirical formulas without a preceding experiment being performed. Initial values of h are simply equivalent to the ratio of the coating thermal conductivity and its thickness ( 1000 Wm-2 K-1). Later, when the air gap is formed, h drops exponentially to values at least one order of magnitude smaller ( 100 Wm-2 K-1).

Repair welding of cast iron coated electrodes

Science.gov (United States)

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

2017-08-01

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

Characterization of Ni–Cr alloys using different casting techniques and molds

International Nuclear Information System (INIS)

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

2014-01-01

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. - Highlights: • Properties of Ni–Cr alloys using various casting techniques are characterized. • Alloys cast by graphite mold exhibited higher recovery angle and more ductility. • Alloys cast by graphite mold exhibited higher strength and grinding rate. • Alloys in this study increase operative room to adjust the precision for prosthesis

Characterization of Ni–Cr alloys using different casting techniques and molds

Energy Technology Data Exchange (ETDEWEB)

Chen, Wen-Cheng, E-mail: wencchen@fcu.edu.tw [Advanced Medical Devices and Composites Laboratory, Department of Fiber and Composite Materials, College of Engineering, Feng Chia University, Taichung 40724, Taiwan (China); Teng, Fu-Yuan [Department of Dentistry, Kaohsiung Armed Forces General Hospital, Kaohsiung 802, Taiwan (China); School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Hung, Chun-Cheng [School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan (China); Department of Dentistry, Kaohsiung Medical University Hospital, Kaohsiung 807, Taiwan (China)

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. - Highlights: • Properties of Ni–Cr alloys using various casting techniques are characterized. • Alloys cast by graphite mold exhibited higher recovery angle and more ductility. • Alloys cast by graphite mold exhibited higher strength and grinding rate. • Alloys in this study increase operative room to adjust the precision for prosthesis.

Casting of Hearth Plates from High-chromium Steel

Directory of Open Access Journals (Sweden)

Drotlew A.

2014-12-01

Full Text Available The paper presents the results of studies on the development of manufacturing technologies to cast hearth plates operating in chamber furnaces for heat treatment. Castings made from the heat-resistant G-X40CrNiSi27-4 steel were poured in hand-made green sand molds. The following operations were performed: computer simulation to predict the distribution of internal defects in castings produced by the above mentioned technology with risers bare and coated with exothermic and insulating sleeves, analysis of each variant of the technology, and manufacture of experimental castings. As a result of the conducted studies and analysis it was found that the use of risers with exothermic sleeves does not affect to a significant degree the quality of the produced castings of hearth plates, but it significantly improves the metal yield.

Thermodynamic stability of austenitic Ni-Mn-Cu cast iron

Directory of Open Access Journals (Sweden)

A. Janus

2014-07-01

Full Text Available The performed research was aimed at determining thermodynamic stability of structures of Ni-Mn-Cu cast iron castings. Examined were 35 alloys. The castings were tempered at 900 °C for 2 hours. Two cooling speeds were used: furnace-cooling and water-cooling. In the alloys with the nickel equivalent value less than 20,0 %, partial transition of austenite to martensite took place. The austenite decomposition ratio and the related growth of hardness was higher for smaller nickel equivalent value and was clearly larger in annealed castings than in hardened ones. Obtaining thermodynamically stable structure of castings requires larger than 20,0 % value of the nickel equivalent.

Bigger helpers in the ant Cataglyphis bombycina: increased worker polymorphism or novel soldier caste?

Directory of Open Access Journals (Sweden)

Mathieu Molet

Full Text Available The mechanisms by which development favors or constrains the evolution of new phenotypes are incompletely understood. Polyphenic species may benefit from developmental plasticity not only regarding ecological advantages, but also potential for evolutionary diversification. For instance, the repeated evolution of novel castes in ants may have been facilitated by the existence of alternative queen and worker castes and their respective developmental programs.Cataglyphis bombycina is exceptional in its genus because winged queens and size-polymorphic workers occur together with bigger individuals having saber-shaped mandibles. We measured seven body parts in more than 150 individuals to perform a morphometric analysis and assess the developmental origin of this novel phenotype.Adults with saber-shaped mandibles differ from both workers and queens regarding the size of most body parts. Their relative growth rates are identical to workers for some pairs of body parts, and identical to queens for other pairs of body parts; critical sizes differ in all cases.Big individuals are a third caste, i.e. soldiers, not major workers. Novel traits such as elongated mandibles are combined with a mix of queen and worker growth rates. We also reveal the existence of a dimorphism in the queen caste (microgynes and macrogynes. We discuss how novel phenotypes can evolve more readily in the context of an existing polyphenism. Both morphological traits and growth rules from existing queen and worker castes can be recombined, hence mosaic phenotypes are more likely to be viable. In C. bombycina, such a mosaic phenotype appears to function both for defense (saber-shaped mandibles and fat storage (big abdomen. Recycling of developmental programs may have contributed to the morphological diversity and ecological success of ants.

Modeling of TiAl Alloy Grating by Investment Casting

OpenAIRE

Yi Jia; Shulong Xiao; Jing Tian; Lijuan Xu; Yuyong Chen

2015-01-01

The investment casting of TiAl alloys has become the most promising cost-effective technique for manufacturing TiAl components. This study aimed to investigate a series of problems associated with the investment casting of TiAl alloys. The mold filling and solidification of this casting model were numerically simulated using ProCAST. Shrinkage porosity was quantitatively predicted by a built-in feeding criterion. The results obtained from the numerical simulations were compared with experimen...

Hot forging of roll-cast high aluminum content magnesium alloys

Science.gov (United States)

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.

A role of the human thalamus in predicting the perceptual consequences of eye movements.

Science.gov (United States)

Ostendorf, Florian; Liebermann, Daniela; Ploner, Christoph J

2013-01-01

Internal monitoring of oculomotor commands may help to anticipate and keep track of changes in perceptual input imposed by our eye movements. Neurophysiological studies in non-human primates identified corollary discharge (CD) signals of oculomotor commands that are conveyed via thalamus to frontal cortices. We tested whether disruption of these monitoring pathways on the thalamic level impairs the perceptual matching of visual input before and after an eye movement in human subjects. Fourteen patients with focal thalamic stroke and 20 healthy control subjects performed a task requiring a perceptual judgment across eye movements. Subjects reported the apparent displacement of a target cue that jumped unpredictably in sync with a saccadic eye movement. In a critical condition of this task, six patients exhibited clearly asymmetric perceptual performance for rightward vs. leftward saccade direction. Furthermore, perceptual judgments in seven patients systematically depended on oculomotor targeting errors, with self-generated targeting errors erroneously attributed to external stimulus jumps. Voxel-based lesion-symptom mapping identified an area in right central thalamus as critical for the perceptual matching of visual space across eye movements. Our findings suggest that trans-thalamic CD transmission decisively contributes to a correct prediction of the perceptual consequences of oculomotor actions.

A role of the human thalamus in predicting the perceptual consequences of eye movements

Directory of Open Access Journals (Sweden)

Florian eOstendorf

2013-04-01

Full Text Available Internal monitoring of oculomotor commands may help to anticipate and keep track of changes in perceptual input imposed by our eye movements. Neurophysiological studies in non-human primates identified corollary discharge signals of oculomotor commands that are conveyed via thalamus to frontal cortices. We tested whether disruption of these monitoring pathways on the thalamic level impairs the perceptual matching of visual input before and after an eye movement in human subjects. Fourteen patients with focal thalamic stroke and twenty healthy control subjects performed a task requiring a perceptual judgment across eye movements. Subjects reported the apparent displacement of a target cue that jumped unpredictably in sync with a saccadic eye movement. In a critical condition of this task, six patients exhibited clearly asymmetric perceptual performance for rightward versus leftward saccade direction. Furthermore, perceptual judgments in seven patients systematically depended on oculomotor targeting errors, with self-generated targeting errors erroneously attributed to external stimulus jumps. Voxel-based lesion-symptom mapping identified an area in right central thalamus as critical for the perceptual matching of visual space across eye movements. Our findings suggest that trans-thalamic corollary discharge transmission decisively contributes to a correct prediction of the perceptual consequences of oculomotor actions.

25 CFR 217.6 - Method of casting votes.

Science.gov (United States)

2010-04-01

... 25 Indians 1 2010-04-01 2010-04-01 false Method of casting votes. 217.6 Section 217.6 Indians.... § 217.6 Method of casting votes. Within 30 days after an issue and any analysis provided for in §§ 217.4... superintendent in writing of the number of votes cast for and against the proposed or alternative solutions. If...

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

Science.gov (United States)

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.

SU-F-T-659: Nanoparticle-Aided Eye Plaque Radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Chin, J [University of Masschusetts-Lowell, Lowell, Massachusetts (United States); Ngwa, W [Harvard Medical School, Boston, MA (United States)

2016-06-15

Purpose: Eye plaque brachytherapy is one of the approaches for radiotherapy treatment for ocular cancers: retinoblastoma and choroidal melanoma. This study, investigates the potential benefits of using gold nanoparticles to enhance therapeutic efficacy during eye plaque brachytherapy. Methods: The EYE PHYSICS Inc. Plaque Simulator program distributed by IsoAid, LLC, Port Richey, Florida was used. It is based on the superposition of dose contributions from individual seeds following the TG–43 formalism. Dose enhancement factor (DEF) values for feasible nanoparticle concentrations from previous studies was used to investigate the benefit of using nanoparticles to enhance dose to tumour or reduce dose to healthy tissue. The dose enhancement factor (DEF) represents the ratio of the dose deposited in tumour with nanoparticles divided by dose deposited in the tumour without nanoparticles. The investigation was done for I–125 and Pd–103 typical sources employed for eye plaque brachytherapy. The prescription dose used is 85 Gy. Results: Lower dose enhancement values were obtained for Pd–103. With DEF of 2 due to gold nanoparticles, critical structure doses reduce by a factor of 2. Optic disc dose is 6.69 Gy and 4.571 Gy, opposite retina dose is 4.064 and 2.484 Gy, lens dose is 12.66 Gy and 9.870 Gy, and fovea dose is 9.85 Gy and 7.275 Gy. With DEF of 3 due to gold nanoparticles, critical structure doses reduce by a factor of 3. Optic disc dose is 4.352 Gy and 2.975 Gy, opposite retina dose is 2.644 Gy and 1.618 Gy, lens dose is 8.322 Gy and 6.427 Gy, and fovea dose is 4.815 Gy and 4.737 Gy. Conclusion: The results of this research predict that using gold nanoparticles will lead to major sparing of dose to critical structures. The finding provides more impetus for the development of nanoparticle–aided brachytherapy.

SU-F-T-659: Nanoparticle-Aided Eye Plaque Radiotherapy

International Nuclear Information System (INIS)

Chin, J; Ngwa, W

2016-01-01

Purpose: Eye plaque brachytherapy is one of the approaches for radiotherapy treatment for ocular cancers: retinoblastoma and choroidal melanoma. This study, investigates the potential benefits of using gold nanoparticles to enhance therapeutic efficacy during eye plaque brachytherapy. Methods: The EYE PHYSICS Inc. Plaque Simulator program distributed by IsoAid, LLC, Port Richey, Florida was used. It is based on the superposition of dose contributions from individual seeds following the TG–43 formalism. Dose enhancement factor (DEF) values for feasible nanoparticle concentrations from previous studies was used to investigate the benefit of using nanoparticles to enhance dose to tumour or reduce dose to healthy tissue. The dose enhancement factor (DEF) represents the ratio of the dose deposited in tumour with nanoparticles divided by dose deposited in the tumour without nanoparticles. The investigation was done for I–125 and Pd–103 typical sources employed for eye plaque brachytherapy. The prescription dose used is 85 Gy. Results: Lower dose enhancement values were obtained for Pd–103. With DEF of 2 due to gold nanoparticles, critical structure doses reduce by a factor of 2. Optic disc dose is 6.69 Gy and 4.571 Gy, opposite retina dose is 4.064 and 2.484 Gy, lens dose is 12.66 Gy and 9.870 Gy, and fovea dose is 9.85 Gy and 7.275 Gy. With DEF of 3 due to gold nanoparticles, critical structure doses reduce by a factor of 3. Optic disc dose is 4.352 Gy and 2.975 Gy, opposite retina dose is 2.644 Gy and 1.618 Gy, lens dose is 8.322 Gy and 6.427 Gy, and fovea dose is 4.815 Gy and 4.737 Gy. Conclusion: The results of this research predict that using gold nanoparticles will lead to major sparing of dose to critical structures. The finding provides more impetus for the development of nanoparticle–aided brachytherapy.

Numerical modelling of the tilt casting processes of titanium alumindes

OpenAIRE

Wang, Hong

2008-01-01

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

Thin wall ductile iron casting as a substitute for aluminum alloy casting in automotive industry

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M. Górny

2009-01-01

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

Comparative study of two commercially pure titanium casting methods

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Renata Cristina Silveira Rodrigues

2010-10-01

Full Text Available The interest in using titanium to fabricate removable partial denture (RPD frameworks has increased, but there are few studies evaluating the effects of casting methods on clasp behavior. OBJECTIVE: This study compared the occurrence of porosities and the retentive force of commercially pure titanium (CP Ti and cobalt-chromium (Co-Cr removable partial denture circumferential clasps cast by induction/centrifugation and plasma/vacuum-pressure. MATERIAL AND METHODS: 72 frameworks were cast from CP Ti (n=36 and Co-Cr alloy (n=36; control group. For each material, 18 frameworks were casted by electromagnetic induction and injected by centrifugation, whereas the other 18 were casted by plasma and injected by vacuum-pressure. For each casting method, three subgroups (n=6 were formed: 0.25 mm, 0.50 mm, and 0.75 mm undercuts. The specimens were radiographed and subjected to an insertion/removal test simulating 5 years of framework use. Data were analyzed by ANOVA and Tukey's to compare materials and cast methods (α=0.05. RESULTS: Three of 18 specimens of the induction/centrifugation group and 9 of 18 specimens of plasma/vacuum-pressure cast presented porosities, but only 1 and 7 specimens, respectively, were rejected for simulation test. For Co-Cr alloy, no defects were found. Comparing the casting methods, statistically significant differences (p<0.05 were observed only for the Co-Cr alloy with 0.25 mm and 0.50 mm undercuts. Significant differences were found for the 0.25 mm and 0.75 mm undercuts dependent on the material used. For the 0.50 mm undercut, significant differences were found when the materials were induction casted. CONCLUSION: Although both casting methods produced satisfactory CP Ti RPD frameworks, the occurrence of porosities was greater in the plasma/vacuum-pressure than in the induction/centrifugation method, the latter resulting in higher clasp rigidity, generating higher retention force values.

Report on results of current and future metal casting

International Nuclear Information System (INIS)

Unal, Cetin; Carlson, Neil N.

2015-01-01

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.

Understanding sexual violence as a form of caste violence

OpenAIRE

Prachi Patil

2016-01-01

The paper attempts to understand narratives of sexual violence anchored within the dynamics of social location of caste and gender. Apparent caste-patriarchy and gender hierarchies which are at play in cases of sexual violence against lower-caste and dalit women speak about differential experiences of rape and sexual abuse that women have in India. The paper endeavours to establish that sexual violence is also a form of caste violence by rereading the unfortunate cases of Bhanwari Devi, Khair...

Modeling of TiAl Alloy Grating by Investment Casting

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Yi Jia

2015-12-01

Full Text Available The investment casting of TiAl alloys has become the most promising cost-effective technique for manufacturing TiAl components. This study aimed to investigate a series of problems associated with the investment casting of TiAl alloys. The mold filling and solidification of this casting model were numerically simulated using ProCAST. Shrinkage porosity was quantitatively predicted by a built-in feeding criterion. The results obtained from the numerical simulations were compared with experiments, which were carried out on Vacuum Skull Furnace using an investment block mold. The investment casting of TiAl grating was conducted for verifying the correctness and feasibility of the proposed method. The tensile test results indicated that, at room temperature, the tensile strength and elongation were approximately 675 MPa and 1.7%, respectively. The microstructure and mechanical property of the investment cast TiAl alloy were discussed.

Costs Analysis of Iron Casts Manufacturing

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S. Kukla

2012-04-01

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

Caste differences in Pseudopolybia compressa (Hymenoptera: Vespidae: Polistinae

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Laura Chavarría Pizarro

2009-12-01

Full Text Available Studies of morphological caste syndromes in the tribe Epiponini help us to understand the evolution of social behavior in insects. Few studies have integrated morphological syndromes of various species from the same or distinct genera. We studied morphological differences between castes from three colonies of Pseudopolybia compressa de Saussure, 1854, in order to relate their caste syndrome with those of other species in the genus. We took eight morphometric measures and females were classified in relation to ovarian development and spermathecal contents. Females of Colony 1 (C1 present a higher distinction between castes than females of Colonies 2 and 3 (C2 and C3, and, in general, queens of the three colonies are larger than workers in some measures but smaller in others. In Pseudopolybia Dalla Torre, 1894, shape rather than size is a more important trait in caste divergence.

Galvanic corrosion of copper-cast iron couples

International Nuclear Information System (INIS)

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

2005-01-01

To ensure the safe encapsulation of spent nuclear fuel rods for geological disposal, SKB are considering using the Copper-Cast Iron Canister, which consists of an outer copper canister and an inner cast iron container. The canister will be placed into boreholes in the bedrock of a geologic repository and surrounded by bentonite clay. In the unlikely event of the outer copper canister being breached, water would enter the annulus between the inner and outer canister and at points of contact between the two metals there would be the possibility of galvanic interactions. Although this subject has been considered previously from both a theoretical standpoint and by experimental investigations there was a need for further experimental studies in support of information provided by SKB to the Swedish regulators (SKI). In the work reported here copper-cast iron galvanic couples were set up in a number of different environments representing possible conditions in the SKB repository. The tests investigated two artificial porewaters at 30 deg C and 50 deg C, under aerated and deaerated conditions. Tests were also carried out in a 30 wt% bentonite slurry made up in artificial groundwater. The potential of the couples and the currents passing between the coupled electrodes were monitored for several months. The effect of growing an oxide film on the surface of the cast iron prior to coupling it with copper was investigated. In addition, some crevice specimens based on the multi-crevice assembly (MCA) design were used to simulate the situation where the copper canister will be in direct contact with the cast iron inner vessel. The electrochemical results are presented graphically in the form of electrode potentials and galvanic corrosion currents as a function of time. The galvanic currents in aerated conditions were much higher than in deaerated conditions. For example, at 30 deg C, galvanic corrosion rates as low as 0.02 μm/year for iron were observed after deaeration, but

Squeeze casting of aluminum alloy A380: Microstructure and tensile behavior

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Li Fang

2015-09-01

Full Text Available A380 alloy with a relatively thick cross-section of 25 mm was squeeze cast using a hydraulic press with an applied pressure of 90 MPa. Microstructure and tensile properties of the squeeze cast A380 were characterized and evaluated in comparison with the die cast counterpart. Results show that the squeeze cast A380 possesses a porosity level much lower than the die cast alloy, which is disclosed by both optical microscopy and the density measurement technique. The results of tensile testing indicate the improved tensile properties, specifically ultimate tensile strength (UTS: 215.9 MPa and elongation (Ef: 5.4%, for the squeeze cast samples over those of the conventional high-pressure die cast part (UTS: 173.7 MPa, Ef: 1.0%. The analysis of tensile behavior shows that the squeeze cast A380 exhibits a high tensile toughness (8.5 MJ·m-3 and resilience (179.3 kJ·m-3 compared with the die cast alloy (toughness: 1.4 MJ·m-3, resilience: 140.6 kJ·m-3, despite that, during the onset of plastic deformation, the strain-hardening rate of the die cast specimen is higher than that of the squeeze cast specimens. The microstructure analyzed by the scanning electron microscopy (SEM shows that both the squeeze and die cast specimens contain the primary α-Al, Al2Cu, Al5FeSi phase and the eutectic Si phase. But, the Al2Cu phase present in the squeeze cast alloy is relatively large in size and quantity. The SEM fractography evidently reveals the ductile fracture features of the squeeze cast A380 alloy.

Quality evaluation of cast Al-SiCp composites

International Nuclear Information System (INIS)

Adalarasu, S.; Mahadevan, S.; Satyanarayana, K.G.; Pai, B.C.; Pillai, R.M.

1996-01-01

This paper presents a methodology for using x-ray radiography and ultrasonic for testing the soundness and distribution of dispersoids and identifying the casting defects in a cast aluminium cast alloy matrix SiCp composites. The ultrasonic inspection could detect in 6061-SiCp cast composites 1) the presence of low levels of locked in stresses and 2) existence of local imperfection due to the combined effects of the local solidification condition and the presence of the dispersoids which were not possible through x-ray radiography. This clearly suggests that ultrasonic test can be used as a powerful NDE tool for screening the composite ingots. (author)

Research on Accuracy of Automatic System for Casting Measuring

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Jaworski J.

2016-09-01

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

Improved ceramic slip casting technique. [application to aircraft model fabrication

Science.gov (United States)

Buck, Gregory M. (Inventor); Vasquez, Peter (Inventor)

1993-01-01

A primary concern in modern fluid dynamics research is the experimental verification of computational aerothermodynamic codes. This research requires high precision and detail in the test model employed. Ceramic materials are used for these models because of their low heat conductivity and their survivability at high temperatures. To fabricate such models, slip casting techniques were developed to provide net-form, precision casting capability for high-purity ceramic materials in aqueous solutions. In previous slip casting techniques, block, or flask molds made of plaster-of-paris were used to draw liquid from the slip material. Upon setting, parts were removed from the flask mold and cured in a kiln at high temperatures. Casting detail was usually limited with this technique -- detailed parts were frequently damaged upon separation from the flask mold, as the molded parts are extremely delicate in the uncured state, and the flask mold is inflexible. Ceramic surfaces were also marred by 'parting lines' caused by mold separation. This adversely affected the aerodynamic surface quality of the model as well. (Parting lines are invariably necessary on or near the leading edges of wings, nosetips, and fins for mold separation. These areas are also critical for flow boundary layer control.) Parting agents used in the casting process also affected surface quality. These agents eventually soaked into the mold, the model, or flaked off when releasing the case model. Different materials were tried, such as oils, paraffin, and even an algae. The algae released best, but some of it remained on the model and imparted an uneven texture and discoloration on the model surface when cured. According to the present invention, a wax pattern for a shell mold is provided, and an aqueous mixture of a calcium sulfate-bonded investment material is applied as a coating to the wax pattern. The coated wax pattern is then dried, followed by curing to vaporize the wax pattern and leave a shell

In-situ inspection of grooves in reactor tube sheet using a remotely operated cast impression taking device

International Nuclear Information System (INIS)

Rajendran, S.; Ramakumar, M.S.

1996-01-01

Utmost importance is given to the in-service inspection of critical components of a reactor to ensure its reliable performance during the reactor operation. This paper describes a cast taking device using cold setting resin to take impression of the grooves being made in the tube sheet for sparger tube installation in pressurised heavy water reactor. (author)

Colour Metallography of Cast Iron - Chapter 2: Grey Iron (Ⅱ

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Zhou Jiyang

2009-08-01

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

Titanium Aluminide Casting Technology Development

Science.gov (United States)

Bünck, Matthias; Stoyanov, Todor; Schievenbusch, Jan; Michels, Heiner; Gußfeld, Alexander

2017-12-01

Titanium aluminide alloys have been successfully introduced into civil aircraft engine technology in recent years, and a significant order volume increase is expected in the near future. Due to its beneficial buy-to-fly ratio, investment casting bears the highest potential for cost reduction of all competing production technologies for TiAl-LPTB. However, highest mechanical properties can be achieved by TiAl forging. In view of this, Access e.V. has developed technologies for the production of TiAl investment cast parts and TiAl die cast billets for forging purposes. While these parts meet the highest requirements, establishing series production and further optimizing resource and economic efficiency are present challenges. In order to meet these goals, Access has recently been certified according to aircraft standards, aiming at qualifying parts for production on technology readiness level 6. The present work gives an overview of the phases of development and certification.

Blinded By Magic: Eye-Movements Reveal the Misdirection of Attention

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Anthony S. Barnhart

2014-12-01

Full Text Available Recent studies (e.g., Kuhn & Tatler, 2005 have suggested that magic tricks can provide a powerful and compelling domain for the study of attention and perception. In particular, many stage illusions involve attentional misdirection, guiding the observer’s gaze to a salient object or event, while another critical action, such as sleight of hand, is taking place. Even if the critical action takes place in full view, people typically fail to see it due to inattentional blindness. In an eye-tracking experiment, participants watched videos of a new magic trick, wherein a coin placed beneath a napkin disappears, reappearing under a different napkin. Appropriately deployed attention would allow participants to detect the secret event that underlies the illusion (a moving coin, as it happens in full view and is visible for approximately 550 ms. Nevertheless, we observed high rates of inattentional blindness. Unlike prior research, eye-movements during the critical event showed different patterns for participants, depending upon whether they saw the moving coin. The results also showed that when participants watched several practice videos without any moving coin, they became far more likely to detect the coin in the critical trial. Taken together, the findings are consistent with perceptual load theory (Lavie & Tsal, 1994.

Engineering of the institutionalization of the circular economy at the level of casting production

Science.gov (United States)

Vescan, M. M.; Soporan, V. F.; Crișan, D. M.; Lehene, T. R.; Pădurețu, S.; Samuila, V.

2017-06-01

This paper is motivated by the necessity of introducing the principles of circular economy at the level of different social - economic activities, and from this point of view one of the fields with a special potential is that of the manufacture of castings. Objective: to connect to the organizing and application of the methodology of the circular economy principles. The proposed method is an innovating one, being connected to the use of institutionalization engineering. Formulating the subject: The subject formulated to be solved aims at the introduction of new approaches, defined through institutionalization engineering, which proposes to set the correlation of actions between the specifics of the circular economy and the specific elements of the manufacture of castings. Research method: An institutional structuring operation was imposed for the optimization of the research method, in which different versions interact at the following levels: the level of public policies, the level of the regulatory framework, the level of technical solutions and the level of financing solutions and financial instruments. The determination of the optimal solution established in a dynamic context, favorable for the requirements of the different actors present within the process, appeals to the elements of critical thinking, specific for the engineer’s actions. Achievement of the research activity: The research activity structures a methodology of quantifying the contributions of each stage of the manufacturing process for castings at the fulfilling of the specific conditions of the circular economy, indicating the critical areas of action for more efficient actions of the circular economy, according to the market economy requirements, where there is a potential of implementing the technical solutions by quantizing the financial solutions and the opportunity of using the financial instruments. The major contribution of the research: The proposed methodology, with examples at the

Effect of vibration frequency on microstructure and performance of high chromium cast iron prepared by lost foam casting

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Wen-qi Zou

2016-07-01

Full Text Available In the present research, high chromium cast irons (HCCIs were prepared using the lost foam casting (LFC process. To improve the wear resistance of the high chromium cast irons (HCCIs, mechanical vibration was employed during the solidification of the HCCIs. The effects of vibration frequency on the microstructure and performance of the HCCIs under as-cast, as-quenched and as-tempered conditions were investigated. The results indicated that the microstructures of the LFC-produced HCCIs were refined due to the introduction of mechanical vibration, and the hardness was improved compared to that of the alloy without vibration. However, only a slight improvement in hardness was found in spite of the increase of vibration frequency. In contrast, the impact toughness of the as-tempered HCCIs increased with an increase in the vibration frequency. In addition, the wear resistance of the HCCIs was improved as a result of the introduction of vibration and increased with an increase in the vibration frequency.

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

Science.gov (United States)

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.

Casting and stress-strain simulations of a cast ductile iron component using microstructure based mechanical behavior

International Nuclear Information System (INIS)

Olofsson, Jakob; Svensson, Ingvar L

2012-01-01

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

Grindability of alpha-case formed on cast titanium.

Science.gov (United States)

Koike, Marie; Jacobson, David; Chan, Kwai S; Okabe, Toru

2009-09-01

The hardened alpha-case (alpha-case) layer inevitably forms on the surface of titanium castings when prepared by investment casting. Because the hardness of the alpha-case is incomparable to that of the interior structure, the perception exists that the alpha-case is difficult to remove during cutting, grinding and polishing. Grindability (ease of grinding) of cast cpTi and cast Ti-6Al-4V was evaluated by grinding cast specimens incrementally using a SiC abrasive wheel. The present study revealed that the presence of the brittle alpha-case with lower fracture toughness is beneficial in grinding titanium. The alpha-case on the ductile cpTi can be ground much easier than its bulk interior structure. In less ductile Ti-6Al-4V, the grinding rate is much higher than that of cpTi, and the alpha-case and its interior structure are at similar levels since the fracture toughness of its alpha-case and the bulk material is not large enough.

A molecular concept of caste in insect societies.

Science.gov (United States)

Sumner, Seirian; Bell, Emily; Taylor, Daisy

2018-02-01

The term 'caste' is used to describe the division of reproductive labour that defines eusocial insect societies. The definition of 'caste' has been debated over the last 50 years, specifically with respect to the simplest insect societies; this raises the question of whether a simple categorisation of social behaviour by reproductive state alone is helpful. Gene-level analyses of behaviours of individuals in hymenopteran social insect societies now provide a new empirical base-line for defining caste and understanding the evolution and maintenance of a reproductive division of labour. We review this literature to identify a set of potential molecular signatures that, combined with behavioural, morphological and physiological data, help define caste more precisely; these signatures vary with the type of society, and are likely to be influenced by ecology, life-history, and stage in the colony cycle. We conclude that genomic approaches provide us with additional ways to help quantify and categorise caste, and behaviour in general. Copyright © 2017 Elsevier Inc. All rights reserved.

Understanding Zora Neale Hurston's Their Eyes Were Watching God

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Tatjana Vukelić

2007-12-01

Full Text Available The work of Zora Neale Hurston, in particular, the novel Their Eyes Were Watching God, has been the object of more than a decade of critical attention. But, in addition to the critical consideration of Hurston's writings, her work has received the level of institutional support necessary for Hurston to enter the American literary mainstream. The article addresses the issue of black women literary tradition and the search for freedom and identity in the white American social and cultural environment.

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

Science.gov (United States)

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

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

Casting metal microstructures from a flexible and reusable mold

International Nuclear Information System (INIS)

Cannon, Andrew H; King, William P

2009-01-01

This paper describes casting-based microfabrication of metal microstructures and nanostructures. The metal was cast into flexible silicone molds which were themselves cast from microfabricated silicon templates. Microcasting is demonstrated in two metal alloys of melting temperature 70 °C or 138 °C. Many structures were successfully cast into the metal with excellent replication fidelity, including ridges with periodicity 400 nm and holes or pillars with diameter in the range 10–100 µm and aspect ratio up to 2:1. The flexibility of the silicone mold permits casting of curved surfaces, which we demonstrate by fabricating a cylindrical metal roller of diameter 8 mm covered with microstructures. The metal microstructures can be in turn used as a reusable molding tool

Criticality safety studies for plutonium–uranium metal fuel pin fabrication facility

International Nuclear Information System (INIS)

Stephen, Neethu Hanna; Reddy, C.P.

2013-01-01

Highlights: ► Criticality safety limits for PUMP-F facility is identified. ► The fissile mass which can be handled safely during alloy preparation is 10.5 kg. ► The number of fuel slugs which can be handled safely during injection casting is 53. ► The number of fuel slugs which can be handled safely after fuel fabrication is 71. - Abstract: This study focuses on the criticality safety during the fabrication of fast reactor metal fuel pins comprising of the fuel type U–15Pu, U–19Pu and U–19Pu–6Zr in the Plutonium–Uranium Metal fuel Pin fabrication Facility (PUMP-F). Maximum amount of fissile mass which can be handled safely during master alloy preparation, Injection casting and fuel slug preparation following fuel pin fabrication were identified and fixed based on this study. In the induction melting furnace, the fissile mass can be limited to 10.5 kg. During fuel slug preparation and fuel pin fabrication, fuel slugs and pins were arranged in hexagonal and square lattices to identify the most reactive configuration. The number of fuel slugs which can be handled safely after injection casting can be fixed to be 53, whereas after fuel fabrication it is 71

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

Science.gov (United States)

2010-07-01

... copper casting subcategory. 464.20 Section 464.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Copper Casting Subcategory § 464.20 Applicability; description of the copper casting subcategory. The...

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

Science.gov (United States)

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...

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

Science.gov (United States)

2010-07-01

... aluminum casting subcategory. 464.10 Section 464.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS METAL MOLDING AND CASTING POINT SOURCE CATEGORY Aluminum Casting Subcategory § 464.10 Applicability; description of the aluminum casting subcategory. The...

EyeGENE

Data.gov (United States)

U.S. Department of Health & Human Services — The eyeGENE® Biorepository and corresponding Database contain family history and clinical eye exam data from subjects enrolled in eyeGENE® Program coupled to...

Detection of Cast Shadows in Surveillance Applications

DEFF Research Database (Denmark)

Erbou, Søren G.; Sørensen, Helge Bjarne Dissing; Stage, Bjarne

2005-01-01

Cast shadows from moving objects reduce the general ability of robust classification and tracking of these objects, in outdoor surveillance applications. A method for segmentation of cast shadows is proposed, combining statistical features with a new similarity feature, derived from a physics...

Bags Under Eyes

Science.gov (United States)

Bags under eyes Overview Bags under eyes — mild swelling or puffiness under the eyes — are common as you age. With aging, the tissues around your ... space below your eyes, adding to the swelling. Bags under eyes are usually a cosmetic concern and ...

In-situ surface hardening of cast iron by surface layer metallurgy

International Nuclear Information System (INIS)

Fischer, Sebastian F.; Muschna, Stefan; Bührig-Polaczek, Andreas; Bünck, Matthias

2014-01-01

Abrasive wear is a serious problem in many cast iron castings used in industry. To minimize failure and repair of these components, different strategies exist to improve their surface microhardness thus enhancing their wear resistance. However, most of these methods lead to very brittle and/or expensive castings. In the current work a new method for surface hardening is presented which utilizes surface layer metallurgy to generate in-situ a boron-enriched white cast iron surface layer with a high microhardness on a gray cast iron casting. To do this, sand molds are coated with a ferroboron suspension and cast with a cast iron melt. After solidification, a 100–900 µm thick layer of boron-enriched ledeburite is formed on the surface of the casting which produces an increase in the average microhardness from 284 HV 0.1 ±52 HV 0.1 to 505 HV 0.1 ±87 HV 0.1 . Analyses of the samples' core reveal a typical cast iron microstructure which leads to the conclusion that the coating mainly affects the castings' surface. By varying the grain size of the ferroboron powder in the coatings, it is shown that a powder size ≤100 µm is most suitable to create a boron-enriched ledeburite surface layer possessing high hardness values

Hydrogen analysis and effect of filtration on final quality of castings from aluminium alloy AlSi7Mg0,3

Directory of Open Access Journals (Sweden)

M. Brůna

2011-01-01

Full Text Available The usage of aluminium and its alloys have increased in many applications and industries over the decades. The automotive industry is the largest market for aluminium castings and cast products. Aluminium is widely used in other applications such as aerospace, marine engines and structures. Parts of small appliances, hand tools and other machinery also use thousands of different aluminium castings. The applications grow as industry seeks new ways to save weight and improve performance and recycling of metals has become an essential part of a sustainable industrial society. The process of recycling has therefore grown to be of great importance, also another aspect has become of critical importance: the achievement of quality and reliability of the products and so is very important to underst and the mechanisms of the formation of defects in aluminium melts, and also to have a reliable and simple means of detection.

Nuclear-waste encapsulation by metal-matrix casting

International Nuclear Information System (INIS)

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

1981-05-01

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

Influence of New Sol-gel Refractory Coating on the Casting Properties of Cold Box and Furan Cores for Grey Cast iron

DEFF Research Database (Denmark)

Nwaogu, Ugochukwu Chibuzoh; Poulsen, T.; Bischoff, C

2010-01-01

New Sol-Gel coated sand cores made from coldbox and furan binder systems were investigated. The idea of the coating was to improve the surface quality of castings. Grey iron was cast on the cores in a sand casting process. The effect of the high temperature of the melt on the cores was assessed...... by measuring the heating curves. The viscosity of the coating, moisture content and the permeability of the cores were evaluated. The surface quality of the castings was investigated using SEM and OM. The results show that the moisture content of the cores affected the permeability. In furan cores the vapour...... transport zone (VTZ) when in contact with the melt is larger than it is in a coldbox which means the furan cores have higher moisture content. The new sol-gel coating has the potential for improving the surface quality of castings without negative effects on the graphite distribution. The surface...

A proposal of parameter to predict biaxial fatigue life for CF8M cast stainless steels

International Nuclear Information System (INIS)

Park, Joong Cheul; Kwon, Jae Do

2005-01-01

Biaxial low cycle fatigue test was carried out to predict fatigue life under combined axial-torsional loading condition which is that of in-phase and out-of-phase for CF8M cast stainless steels. Fatemi Socie(FS) parameter which is based on critical plane approach is not only one of methods but also the best method that can predict fatigue life under biaxial loading condition. But the result showed that, biaxial fatigue life prediction by using FS parameter with several different parameters for the CF8M cast stainless steels is not conservative but best results. So in this present research, we proposed new fatigue life prediction parameter considering effective shear stress instead of FS parameter which considers the maximum normal stress acting on maximum shear strain and its effectiveness was verified

On the performance of a novel grain refiner in hyper-eutectic Al-Si cast alloys

OpenAIRE

Bolzoni, L; Nowak, M; Hari Babu, N

2014-01-01

The stringent requirements for pollution reduction are pushing the automotive industry towards the employment of lightweight structures and, therefore, aluminium and its alloys play a remarkable role. Al-Si casting alloy with eutectic or hyper- eutectic compositions are, normally, employed for the production of high performance automotive products such as pistons and engine blocks which have to withstand critical loading conditions (i.e. high temperature, high pressure and corrosive exhaust g...

What Is Dry Eye?

Medline Plus

Full Text Available ... Español Eye Health / Eye Health A-Z Dry Eye Sections What Is Dry Eye? Dry Eye Symptoms ... Dry Eye Dry Eye Treatment What Is Dry Eye? Leer en Español: ¿Qué es el ojo seco? ...

40 CFR 464.40 - Applicability; description of the zinc casting subcategory.

Science.gov (United States)

2010-07-01

... casting subcategory. 464.40 Section 464.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (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 420.60 - Applicability; description of the continuous casting subcategory.

Science.gov (United States)

2010-07-01

... continuous casting subcategory. 420.60 Section 420.60 Protection of Environment ENVIRONMENTAL PROTECTION... Continuous Casting Subcategory § 420.60 Applicability; description of the continuous casting subcategory. The... owned treatment works resulting from the continous casting of molten steel into intermediate or semi...

Study on wear resistance of vanadium alloying compacted/vermicular graphite cast iron

International Nuclear Information System (INIS)

Park, Yoon Woo

1987-01-01

Wear resistance of the Compacted/Vermicular graphite cast irons was studied by changing the vanadium content in the cast irons. The results obtained in this work are summarized as follows. 1. When the same amount of vanadium was added to the flake graphite cast iron, spheroidal graphitecast iron and Compacted/Vermicular graphite cast iron, spheroidal graphite cast iron and Compacted/Vermicular graphite cast iron wear resistance decreased in following sequence, that is, flake graphite cast iron> spheroidal graphite cast iron>Compacted/Vermicular graphite cast iron. 2. Addition of vanadium to the Compacted/Vermicular cast iron leaded to a remarkable increase in hardness because it made the amount of pearlite in matrix increase. 3. Addition of vanadium to the compacted/Vermicular graphite cast iron significantly enhanced wear resistance and the maximum resistance was achieved at about 0.36% vanadium. 4. The maximum amount of wear apppeared at sliding speed of about 1.4m/sec and wear mode was considered to be oxidation abrasion from the observation of wear tracks. (Author)

What Is Dry Eye?

Medline Plus

Full Text Available ... Stories Español Eye Health / Eye Health A-Z Dry Eye Sections What Is Dry Eye? Dry Eye Symptoms ... of Dry Eye Dry Eye Treatment What Is Dry Eye? Leer en Español: ¿Qué es el ojo seco? ...

ToxCast Dashboard

Science.gov (United States)

The ToxCast Dashboard helps users examine high-throughput assay data to inform chemical safety decisions. To date, it has data on over 9,000 chemicals and information from more than 1,000 high-throughput assay endpoint components.

About the Eye

Medline Plus

Full Text Available ... Ask a Scientist Video Series Glossary The Visual System Your Eyes’ Natural Defenses Eye Health and Safety First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun Stuff Cool Eye Tricks Links to More Information Optical Illusions Printables About the Eye Your eyes ...

The role of serial casting in early-onset scoliosis (EOS).

Science.gov (United States)

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

Combined testing of castings having rough surface

International Nuclear Information System (INIS)

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

1988-01-01

Mathematical models of a flaw detector for complex testing of castings, containing radiometric and pneumatic converters, are developed and investigated. The efficiency of compensation of casting thickness fluctuation effect on the results of testing in combined information processing obtained by various methods is estimated

Friction welding of ductile cast iron using interlayers

International Nuclear Information System (INIS)

Winiczenko, Radoslaw; Kaczorowski, Mieczyslaw

2012-01-01

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

Eye Care Professionals' Perspectives on Eye Donation and an Eye Donation Registry for Research: A Single-Institution, Cross-Sectional Study.

Science.gov (United States)

Williams, Andrew M; Allingham, R Rand; Stamer, W Daniel; Muir, Kelly W

2016-06-01

A centralized eye donation registry for research could help to bridge the gap between patients interested in donating their eyes to science and scientists who conduct research on human eye tissue. Previous research has demonstrated patient and family support for such a registry. In this study, we assessed the views that eye care professionals have toward an eye donation registry for research. Surveys were distributed to all 46 clinical faculty members of the Duke University Eye Center. In addition to collecting demographic information, the surveys assessed clinicians' experience with discussing eye donation with patients, described the proposed eye donation registry for research and asked how the registry would affect the clinicians' practice. A total of 21 eye care professionals returned the survey. Thirty-three percent reported discussing eye donation with patients, and 43% reported that a patient has asked about donating their eyes for research on their disease. Eighty-six percent of eye care professionals reported that a centralized registry would improve the way they work with patients who express a desire to donate their eyes for research. The majority of eye care professionals at our academic institution indicated that an eye donation registry for research would improve how they work with patients who are interested in donating their eyes for research on their disease. Future research should examine how best to communicate this registry to ophthalmic patients.

CASTING FURNACES

Science.gov (United States)

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.

Analysis of Mold Friction in a Continuous Casting Using Wavelet Transform

Science.gov (United States)

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.

Results of Casting in Severe Curves in Infantile Scoliosis.

Science.gov (United States)

Stasikelis, Peter J; Carpenter, Ashley M

2018-04-01

Previous work has demonstrated best results for casting in infantile scoliosis when the curves are small and the child begins casting under 2 years of age. This study examines if casting can delay the need for growth friendly instrumentation in severe curves (50 to 106 degrees) and how the comorbidities of syrinx or genetic syndromes affected outcomes. All children undergoing casting for scoliosis at a single institution over an 8-year period were examined. Inclusion criteria included initial curve at first casting of ≥50 degrees, age ≤3 years at the start of casting, and a minimum follow-up of 3 years. Of 148 children undergoing casting during this period, 44 met our inclusion criteria. All children underwent magnetic resonance imaging. Ten children with a syrinx were identified. Ten children had known genetic syndromes (2 who also had a syrinx). The 26 children without these comorbidities were considered idiopathic. Curve magnitude ranged from 50 to 106 degrees. Nine of the 26 (35%) children in the children with idiopathic curves demonstrated resolution of their curves, while only 3 of the remaining 18 (17%) did. Of the children that did not have resolution of their curves, 14 were maintained over the entire follow-up period to within 15 degrees of their initial curve and 13 were improved 15 degrees or more. Only 5 children had an increase of 15 degrees or more over the follow-up period and 4 of these have undergone growth friendly instrumentation after a mean delay from initial cast of 71 months (range, 18 to 100 mo). This study demonstrates that even in severe curves, casting was effective in delaying instrumentation in all cases, and led to curve resolution of the curves in 12 of 44 children. Level III-case control study.

29 CFR 452.131 - Casting of ballots; delegate elections.

Science.gov (United States)

2010-07-01

... 29 Labor 2 2010-07-01 2010-07-01 false Casting of ballots; delegate elections. 452.131 Section 452... REPORTING AND DISCLOSURE ACT OF 1959 Election Procedures; Rights of Members § 452.131 Casting of ballots; delegate elections. The manner in which the votes of the representatives are cast in the convention is not...

Effects of calpastain (CAST) polymorphisms on carcass and meat ...

African Journals Online (AJOL)

Calpastain (CAST) activity plays a major role in muscle growth and proteolytic changes post-mortem and the CAST gene has been considered as a candidate gene for carcass and pork quality characteristics. The aim of this study was to analyze the association of two polymorphisms namely CAST_HinfI (allele A and B) and ...

CAST Status Report to the SPSC for the 123rd Meeting

CERN Document Server

Desch, K

2016-01-01

After the successful 2015 data taking with Micromegas detectors, targeting solar axion search, and with an InGrid detector, targeting solar chameleon search, CAST has started on its new 2016-2018 program which has been presented to SPSC at the 119th meeting in October 2015. This program extends the physics goals of CAST towards the search for solar chameleons using a force sensor (KWISP) and towards the search for relic axions using a microwave cavity inserted into the CAST magnet (CAST-CAPP). The search for solar chameleons and other axion-like particles was continued with a significantly upgraded InGrid detector. The new experiments make use different elements of the unique CAST infrastructure (KWISP: Abrixas XRT and sun pointing capability of CAST, CAST-CAPP: high magnetic dipole field), while the InGrid detector exploits all of CAST´s features (Abrixas XRT, high magnetic dipole field, sun pointing). All three experiments within CAST have made significant progress in exploring these new approaches in 2016...

Investment casting of beta titanium alloys for aerospace applications

International Nuclear Information System (INIS)

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

1993-01-01

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

Mechanical properties of ductile cast iron and cast steel for intermediate level waste transport containers

International Nuclear Information System (INIS)

Gray, I.L.S.; Sievwright, R.W.T.; Egid, B.; Ajayi, F.; Donelan, P.

1994-01-01

UK Nirex Ltd is developing Type B re-usable shielded transport containers (RSTCs) in a range of shielding thicknesses to transport intermediate level radioactive waste (ILW) to a deep repository. The designs are of an essentially monolithic construction and rely principally on the plastic flow of their material to absorb the energies involved in impact events. Nirex has investigated the feasibility of manufacturing the RSTCs from ductile cast iron (DCI) or cast steel instead of from forgings, since this would bring advantages of reduced manufacturing time and costs. However, cast materials are perceived to lack toughness and ductility and it is necessary to show that sufficient fracture toughness can be obtained to preclude brittle failure modes, particularly at low temperatures. The mechanical testing carried out as part of that programme is described. It shows how the measured properties have been used to demonstrate avoidance of brittle fracture and provide input to computer modelling of the drop tests. (author)

Dome style heavy wall steel casting manufactured by metallic core mould system

International Nuclear Information System (INIS)

Yamamoto, Shiro; Saeki, Keiji; Hirose, Yutaka; Takebayashi, Kazunari; Kawasaki, Masatoshi

1986-01-01

Semi-spherical thick walled steel castings are one of the main products of Nippon Chutanko K.K., but there have been the problems of internal defects peculiar to large thick walled steel castings, and the various improvements have been carried out so far for the manufacturing method, but still some of those remains. Based on the anxiety about the reliability of large steel castings, the conversion to forging has been studied. For the purpose of thoroughly improving the internal quality of thick walled steel castings to compete with forgings, on the basis of the operating experience of chills, the development of the casting techniques changing cores completely to metallic cores has been advanced. After the preliminary experiment using models, a semi-spherical thick walled steel casting mentioned before was manufactured by this metallic core casting method for trial, and the detailed investigation was carried out. As the result, the excellent internal quality was confirmed, accordingly at present, the production is made by this method. The form, dimensions and specification of the semi-spherical thick walled steel castings, the conventional casting plan, the metallic core casting plan, the design of metallic cores, molding and casting, and the examination of the castings made for trial are reported. (Kako, I.)

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

Science.gov (United States)

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 (Pcasting 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.

Casting and dozing recovers deep seams

Energy Technology Data Exchange (ETDEWEB)

1992-04-01

Juliana Mining Co. has combined cast blasting with a team of dozers to maintain a competitive position at its Amos mine in West Virgina. Up to 100 ft of cover is removed with trucks and loaders, and then the pit is bridged, so the upper material can be placed on top of the spoil. Cast blasting creates two major advantages: short distances and downhill pushes. 5 figs.

En Route towards European Clinical Breakpoints for Veterinary Antimicrobial Susceptibility Testing: A Position Paper Explaining the VetCAST Approach

Science.gov (United States)

Toutain, Pierre-Louis; Bousquet-Mélou, Alain; Damborg, Peter; Ferran, Aude A.; Mevius, Dik; Pelligand, Ludovic; Veldman, Kees T.; Lees, Peter

2017-01-01

VetCAST is the EUCAST sub-committee for Veterinary Antimicrobial Susceptibility Testing. Its remit is to define clinical breakpoints (CBPs) for antimicrobial drugs (AMDs) used in veterinary medicine in Europe. This position paper outlines the procedures and reviews scientific options to solve challenges for the determination of specific CBPs for animal species, drug substances and disease conditions. VetCAST will adopt EUCAST approaches: the initial step will be data assessment; then procedures for decisions on the CBP; and finally the release of recommendations for CBP implementation. The principal challenges anticipated by VetCAST are those associated with the differing modalities of AMD administration, including mass medication, specific long-acting product formulations or local administration. Specific challenges comprise mastitis treatment in dairy cattle, the range of species and within species breed considerations and several other variable factors not relevant to human medicine. Each CBP will be based on consideration of: (i) an epidemiological cut-off value (ECOFF) – the highest MIC that defines the upper end of the wild-type MIC distribution; (ii) a PK/PD breakpoint obtained from pre-clinical pharmacokinetic data [this PK/PD break-point is the highest possible MIC for which a given percentage of animals in the target population achieves a critical value for the selected PK/PD index (fAUC/MIC or fT > MIC)] and (iii) when possible, a clinical cut-off, that is the relationship between MIC and clinical cure. For the latter, VetCAST acknowledges the paucity of such data in veterinary medicine. When a CBP cannot be established, VetCAST will recommend use of ECOFF as surrogate. For decision steps, VetCAST will follow EUCAST procedures involving transparency, consensus and independence. VetCAST will ensure freely available dissemination of information, concerning standards, guidelines, ECOFF, PK/PD breakpoints, CBPs and other relevant information for AST

En Route towards European Clinical Breakpoints for Veterinary Antimicrobial Susceptibility Testing: A Position Paper Explaining the VetCAST Approach.

Science.gov (United States)

Toutain, Pierre-Louis; Bousquet-Mélou, Alain; Damborg, Peter; Ferran, Aude A; Mevius, Dik; Pelligand, Ludovic; Veldman, Kees T; Lees, Peter

2017-01-01

VetCAST is the EUCAST sub-committee for Veterinary Antimicrobial Susceptibility Testing. Its remit is to define clinical breakpoints (CBPs) for antimicrobial drugs (AMDs) used in veterinary medicine in Europe. This position paper outlines the procedures and reviews scientific options to solve challenges for the determination of specific CBPs for animal species, drug substances and disease conditions. VetCAST will adopt EUCAST approaches: the initial step will be data assessment; then procedures for decisions on the CBP; and finally the release of recommendations for CBP implementation. The principal challenges anticipated by VetCAST are those associated with the differing modalities of AMD administration, including mass medication, specific long-acting product formulations or local administration. Specific challenges comprise mastitis treatment in dairy cattle, the range of species and within species breed considerations and several other variable factors not relevant to human medicine. Each CBP will be based on consideration of: (i) an epidemiological cut-off value (ECOFF) - the highest MIC that defines the upper end of the wild-type MIC distribution; (ii) a PK/PD breakpoint obtained from pre-clinical pharmacokinetic data [this PK/PD break-point is the highest possible MIC for which a given percentage of animals in the target population achieves a critical value for the selected PK/PD index ( f AUC/MIC or f T > MIC)] and (iii) when possible, a clinical cut-off, that is the relationship between MIC and clinical cure. For the latter, VetCAST acknowledges the paucity of such data in veterinary medicine. When a CBP cannot be established, VetCAST will recommend use of ECOFF as surrogate. For decision steps, VetCAST will follow EUCAST procedures involving transparency, consensus and independence. VetCAST will ensure freely available dissemination of information, concerning standards, guidelines, ECOFF, PK/PD breakpoints, CBPs and other relevant information for AST

En Route towards European Clinical Breakpoints for Veterinary Antimicrobial Susceptibility Testing: A Position Paper Explaining the VetCAST Approach

Directory of Open Access Journals (Sweden)

Pierre-Louis Toutain

2017-12-01

Full Text Available VetCAST is the EUCAST sub-committee for Veterinary Antimicrobial Susceptibility Testing. Its remit is to define clinical breakpoints (CBPs for antimicrobial drugs (AMDs used in veterinary medicine in Europe. This position paper outlines the procedures and reviews scientific options to solve challenges for the determination of specific CBPs for animal species, drug substances and disease conditions. VetCAST will adopt EUCAST approaches: the initial step will be data assessment; then procedures for decisions on the CBP; and finally the release of recommendations for CBP implementation. The principal challenges anticipated by VetCAST are those associated with the differing modalities of AMD administration, including mass medication, specific long-acting product formulations or local administration. Specific challenges comprise mastitis treatment in dairy cattle, the range of species and within species breed considerations and several other variable factors not relevant to human medicine. Each CBP will be based on consideration of: (i an epidemiological cut-off value (ECOFF – the highest MIC that defines the upper end of the wild-type MIC distribution; (ii a PK/PD breakpoint obtained from pre-clinical pharmacokinetic data [this PK/PD break-point is the highest possible MIC for which a given percentage of animals in the target population achieves a critical value for the selected PK/PD index (fAUC/MIC or fT > MIC] and (iii when possible, a clinical cut-off, that is the relationship between MIC and clinical cure. For the latter, VetCAST acknowledges the paucity of such data in veterinary medicine. When a CBP cannot be established, VetCAST will recommend use of ECOFF as surrogate. For decision steps, VetCAST will follow EUCAST procedures involving transparency, consensus and independence. VetCAST will ensure freely available dissemination of information, concerning standards, guidelines, ECOFF, PK/PD breakpoints, CBPs and other relevant information

The labor/land ratio and India's caste system

OpenAIRE

Duleep, Harriet

2012-01-01

This paper proposes that India’s caste system and involuntary labor were joint responses by a nonworking landowning class to a low labor/land ratio in which the rules of the caste system supported the institution of involuntary labor. The hypothesis is tested in two ways: longitudinally, with data from ancient religious texts, and cross-sectionally, with twentieth-century statistics on regional population/land ratios linked to anthropological measures of caste-system rigidity. Both the longit...

Ropes eye plaque brachytherapy dosimetry for two models of 103Pd seeds

International Nuclear Information System (INIS)

Saidi, P.; Sadeghi, M.; Shirazi, A.; Tenreiro, C.

2011-01-01

Full text: Brachytherapy dose distributions are calculated for I5 m m ROPES eye plaque loaded with model Theragenics200 and IR06-103Pd seeds. The effects of stainless steel backing and Acrylic insert on dose distribution along the central axis of the eye plaque and at critical ocular structure are investigated. Monte Carlo simulation was carried out with the Version 5 of the MCNP. The dose at critical ocular structure by considering the eye composition was calculated. Results are compared with the calculated data for CaMS eye plaque loaded with Theragenics200 palladium-103 seeds and model 6711 iodine-125 seed. The air kerma strength of the IR06- 103Pd seed to deliver 85 Gy in apex of tumor in water medium was calculated to be 4.10 U/seed. Along the central axis of stainless steel plaque loaded with new 103Pd seeds in Acrylic insert, the dose reduction relative to water is 6.9% at 5 mm (apex). Removal of the Acrylic insert from the plaque (replacing with water) did not make significantly difference in dose reduction results (O.2%). The presence of the stainless steel backing results in dose enhancement near the plaque relative to water. Doses at points of interest are higher for ROPES eye plaque when compared to CaMS eye plaque. The dosimetric parameters calculated in this work for the new palladium seed, showed that in dosimetry point of view, the IR06-103Pd seed is suitable for use in brachytherapy. The effect of Acrylic insert on dose distribution is negligible and the main effect on dose reduction is due to the presence of stainless steel plaque backing. (author)

Application of film-casting technique to investigate drug-polymer miscibility in solid dispersion and hot-melt extrudate.

Science.gov (United States)

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

2015-07-01

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

ShakeCast: Automating and improving the use of shakemap for post-earthquake deeision-making and response

Science.gov (United States)

Wald, D.; Lin, K.-W.; Porter, K.; Turner, Loren

2008-01-01

When a potentially damaging earthquake occurs, utility and other lifeline managers, emergency responders, and other critical users have an urgent need for information about the impact on their particular facilities so they can make appropriate decisions and take quick actions to ensure safety and restore system functionality. ShakeMap, a tool used to portray the extent of potentially damaging shaking following an earthquake, on its own can be useful for emergency response, loss estimation, and public information. However, to take full advantage of the potential of ShakeMap, we introduce ShakeCast. ShakeCast facilitates the complicated assessment of potential damage to a user's widely distributed facilities by comparing the complex shaking distribution with the potentially highly variable damageability of their inventory to provide a simple, hierarchical list and maps of structures or facilities most likely impacted. ShakeCast is a freely available, post-earthquake situational awareness application that automatically retrieves earthquake shaking data from ShakeMap, compares intensity measures against users' facilities, sends notifications of potential damage to responsible parties, and generates facility damage maps and other Web-based products for both public and private emergency managers and responders. ?? 2008, Earthquake Engineering Research Institute.

Recurrent cholangitis in the tropics: Worm or cast?

Directory of Open Access Journals (Sweden)

Jain P

2010-01-01

Full Text Available The development of biliary casts is very rare, especially in non-liver transplant patients. The etiology of these casts is uncertain but several factors have been proposed which lead to bile stasis and/or gallbladder hypo-contractility and promote cast formation. Here, we report a 54-year-old male, with diabetes and ischemic heart disease, who presented with recurrent attacks of cholangitis. Magnetic resonance cholangiopancreatography revealed linear T1 hyperintense and T2 hypointense filling defects in the right and left hepatic ducts extending into the common hepatic duct, and a calculus in the lower common bile duct, raising a suspicion of worm in the biliary tree. In view of failed attempts at extraction on endoscopy, patient underwent surgery. At exploration, biliary casts and stones were extracted from the proximal and the second order bile ducts, with the help of intraoperative choledochoscopy and a bilio-enteric anastomosis was accomplished. Although endoscopic retrieval of the biliary cast can be employed as first-line management, surgery should be considered in case it fails.

Effects of Antifungal Soaked Silicone Hydrogel Contact Lenses on Candida albicans in an Agar Eye Model.

Science.gov (United States)

Phan, Chau-Minh; Bajgrowicz, Magdalena; McCanna, David J; Subbaraman, Lakshman N; Jones, Lyndon

2016-09-01

To evaluate the effects of two commercial silicone hydrogel contact lenses (CLs) soaked with natamycin (NA) or fluconazole (FL) on the growth of Candida albicans in an in vitro eye model. Three-D printed molds were used as a cast for making eye-shaped models comprising potato dextrose agar. Senofilcon A (SA) and lotrafilcon B (LB) CLs were incubated with either 2 mL of NA or FL at a concentration of 1 mg/mL for 24 hr. To simulate a fungal infection, the eye models were coated with C. albicans. The drug-soaked lenses were placed on top of the eye models. Seven experimental conditions were examined: (1) NA-SA, (2) NA-LB, (3) FL-SA, (4) FL-LB, (5) SA, (6) LB, and (7) control-no lens. At specified time points (t=1, 8, 16, 24, 48 hr), the agar eyes from each experimental condition were removed from the incubator and photographed. The yeast cells from the 24 and 48 hr time point were also analyzed using light microscopy. At 24 and 48 hr, there was considerable growth observed for all conditions except for the NA-SA and NA-LB conditions. When observed under the microscope at 24 and 48 hr, the morphology of the yeast cells in the FL-SA and SA condition were similar to that of the control (oval shaped). There was limited hyphae growth observed for LB and significant visible hyphae growth for the NA-LB group. For NA-SA, NA-LB, and FL-LB groups, the cells were significantly smaller compared with the control. For NA-SA and NA-LB, there was limited growth of C. albicans observed on the eye models even after 48 hr. Under the microscope, the cell morphology differ noticeably between each testing condition, and is dependent on drug-lens combinations.

Pressing Speed, Specific Pressure and Mechanical Properties of Aluminium Cast

Directory of Open Access Journals (Sweden)

Gaspar S.

2016-06-01

Full Text Available Recent research in the process of aluminum alloy die castings production, which is nowadays deeply implemented into the rapidly growing automobile, shipping and aircraft industries, is aimed at increasing the useful qualitative properties of the die casting in order to obtain its high mechanical properties at acceptable economic cost. Problem of technological factors of high pressure die casting has been a subject of worldwide research (EU, US, Japan, etc.. The final performance properties of die castings are subjected to a large number of technological factors. The main technological factors of high pressure die casting are as follows: plunger pressing speed, specific (increase pressure, mold temperature as well as alloy temperature. The contribution discusses the impact of the plunger pressing speed and specific (increase pressure on the mechanical properties of the casting aluminum alloy.

Critical Involvement of Macrophage Infiltration in the Development of Sjogren's Syndrome-Associated Dry Eye

NARCIS (Netherlands)

Zhou, D.; Chen, Y.T.; Chen, F.L.; Gallup, M.; Vijmasi, T.; Bahrami, A.F.; Noble, L.B.; van Rooijen, N.; McNamara, N.A.

2012-01-01

Lymphocytic infiltration of the lacrimal gland and ocular surface in autoimmune diseases such as Sjögren's syndrome (SS) causes an aqueous-deficient dry eye that is associated with significant morbidity. Previous studies from our laboratory and others have established autoimmune regulator

Eye Movement Disorders

Science.gov (United States)

... work properly. There are many kinds of eye movement disorders. Two common ones are Strabismus - a disorder ... in "crossed eyes" or "walleye." Nystagmus - fast, uncontrollable movements of the eyes, sometimes called "dancing eyes" Some ...

Effect of Melting Techniques on Ductile Iron castings Properties

Directory of Open Access Journals (Sweden)

Bockus, S.

2006-01-01

Full Text Available The study was designed to investigate the effects of the charge, melting conditions, nodularizing and inoculation on the ductile iron castings properties. Results showed that the temperature and holding time of the melt in an induction furnace and the intensity of spheroidizing effect on the carbon and residual magnesium contents in the ductile iron castings. The same grade of ductile iron may be obtained using different chemical compositions. The castings of ductile iron will be ferritic as-cast only when large amount of pig iron in the charge and in addition some-steps inoculating treatment are used.

Investment casting or powder metallurgy – the ecological aspect

Directory of Open Access Journals (Sweden)

J. Tomasik

2009-04-01

Full Text Available The paper presents an analysis of manufacturing methods of material-saving products in relation to investment castings and sinteredpowder technology. Surface microgeometry, shape accuracy, performance parameters, manufacturing costs and energy consumption weretaken into account to make the optimal choice. The analysis was conducted by comparing test results for sintered powder products basedon Distaloy AB alloy that consists of 0.55% C, 1.5% Cu, 1.75% Ni and 0.5% Mo and investment castings made of high alloy cast steel andnodular cast iron. The analysis made it possible to choose the best technology, considering also the ecological aspect.

Comparative study on microstructures and mechanical properties of the heat-treated Al–5.0Cu–0.6Mn–xFe alloys prepared by gravity die casting and squeeze casting

International Nuclear Information System (INIS)

Lin, Bo; Zhang, WeiWen; Lou, ZhaoHui; Zhang, DaTong; Li, YuanYuan

2014-01-01

Highlights: • Only two kind Fe-rich intermetallics are found in the heat-treated Al–5.0Cu–0.6Mn–xFe alloys. • Squeeze cast Al–5.0Cu–0.6Mn alloys containing 1.5% Fe have desirable mechanical properties. • The difference between gravity die cast and squeeze cast Al–5.0Cu–0.6Mn–xFe alloys. - Abstract: The Al–5.0 wt% Cu–0.6 wt% Mn alloys with different Fe contents were prepared by gravity die casting and squeeze casting. The difference in microstructures and mechanical properties of the T5 heat-treated alloys was examined by tensile test, optical microscopy, deep etching technique, scanning electron microscope and electron probe micro-analyzer. The results show that both β-Fe and α (CuFe) are observed in T5 heat-treated gravity die cast alloy and only α (CuFe) appears in the squeeze cast alloy when the Fe content is 0.5 wt%. When the Fe content is more than 1.0 wt%, the main Fe-rich intermetallics is α (CuFe) in both squeeze cast and gravity die cast alloys. The mechanical properties of both the gravity die cast and squeeze cast alloys decrease gradually with the increase of Fe content due to the decreased volume fraction of precipitation particles, the increased volume fraction of Fe-rich intermetallics and the increased size of α (Al) dendrites. The squeeze cast alloys with different Fe contents have superior mechanical properties compared to the gravity die cast alloys, which is mainly attributed to the reduction of porosity and refinement of Fe-rich intermetallics and α (Al) dendrite. In particularly, the elongation of the squeeze cast alloys is less sensitive to the Fe content than that of the gravity die cast alloys. An elongation level of 13.7% is obtained in squeeze cast alloy even when the Fe content is as high as 1.5%, while that of the gravity die cast alloy is only 5.3%

Casting Porosity-Free Grain Refined Magnesium Alloys

Energy Technology Data Exchange (ETDEWEB)

Schwam, David [Case Western Reserve University

2013-08-12

The objective of this project was to identify the root causes for micro-porosity in magnesium alloy castings and recommend remedies that can be implemented in production. The findings confirm the key role played by utilizing optimal gating and risering practices in minimizing porosity in magnesium castings. 

To Stand Steadfast and Love Blackness in These Political Times: A Comparative Reflection from Ghana to the Us and Back Again

Science.gov (United States)

Dillard, Cynthia B.

2017-01-01

This article casts a critical eye on the political moment in the US and the world, ushered in by the election and governance of a person who, in my opinion, enacts openly racist, sexist, authoritarian and narcissist views in both his decisions and being as the US President. The author argues that this is also a moment to stand in steadfastness…

Undercooling and nodule count in thin walled ductile iron castings

DEFF Research Database (Denmark)

Pedersen, Karl Martin; Tiedje, Niels Skat

2007-01-01

Casting experiments have been performed with eutectic and hypereutectic castings with plate thicknesses from 2 to 8 mm involving both temperature measurements during solidification and microstructural examination afterwards. The nodule count was the same for the eutectic and hypereutectic casting...

Simulation of mould filling process for composite skeleton castings

Directory of Open Access Journals (Sweden)

M. Dziuba

2008-04-01

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

Particle attraction effects on the centrifugal casting and extrusion of alumina

International Nuclear Information System (INIS)

Schilling, C.H.; Bergstroem, L.; Ker, H.L.; Aksay, I.A.

1993-01-01

Interparticle attraction forces were empirically related to the centrifugal casting and extrusion behavior of flocculated alumina suspensions. Attractive forces were altered by two approaches: Salt flocculation, which entails regulating the electrical double-layer thickness through electrolyte additions; and screening of van der Waals attraction by steric interactions of surface-adsorbed fatty acids. Specimens produced by both compressibility at a critical maximum density that increased with decreasing interparticle attraction. Gradients in packing density during centrifugal casting were alleviated using both methods as long as spatial variations of the effective stress were within the low-compressibility range. We hypothesized that the reduced interparticle attraction in both methods may also raise the threshold packing density at which ductile-to-brittle transitions occur during plastic shear. Specimens prepared with oleic acid adlayers were highly plastic and easily extrudable at solids contents of up to 59 vol%, although salt-flocculated samples at 55 vol% density extruded at creeping flow rates that were insensitive to the applied pressure. Results suggested that particle rearrangement during shear, is a rate-limiting process, with an average relaxation time that is lowered by reducing interparticle attraction

Defect detection method in digital radiography for porosity in magnesium castings

International Nuclear Information System (INIS)

Rebuffel, V.; Sood, S.; Blakeley, B.

2006-01-01

European project MAGCAST has been devoted to X-rays inspection of magnesium components of complex shapes, as used in spatial, aeronautics, or automotive industries. Porosity affects seriously casting quality, and is critical for safety parts. A radiographic system has been designed, and optimised considering the specific requirements, defect size, and component characteristics. It is composed of a stable mini-focus generator, a direct-conversion detector, and software. In this paper we focus on the numerical method ensuring the automatic detection from the obtained radiographs. The principle consists in a subtraction of a reference image, then a defect extraction on the resulting flattened image. We propose an original algorithm to built off-line a reference image from a set of radiographs acquired using different components. The purpose is to get a completely defect-free reference image, associated to a confidence map. After subtraction of this reference image to the on-line acquired radiograph, an extraction step is performed, taken into account the residual errors due to non-perfect previous steps within the framework of a bayesian segmentation method. Characteristics on defect are also computed, to allow a later classification. Experimental validation of the method on industrial castings is discussed. (orig.)

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

Science.gov (United States)

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 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 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.

About the Eye

Medline Plus

Full Text Available ... for Kids >> About the Eye Listen All About Vision About the Eye Ask a Scientist Video Series ... Eye Health and Safety First Aid Tips Healthy Vision Tips Protective Eyewear Sports and Your Eyes Fun ...

About the Eye

Medline Plus

Full Text Available ... eye behind the iris that helps to focus light on the retina. It allows the eye to ... of the eye. It regulates the amount of light entering the eye through the pupil. Pupil (PYOO- ...

[Comparison of surface light scattering of acrylic intraocular lenses made by lathe-cutting and cast-molding methods--long-term observation and experimental study].

Science.gov (United States)

Nishihara, Hitoshi; Ayaki, Masahiko; Watanabe, Tomiko; Ohnishi, Takeo; Kageyama, Toshiyuki; Yaguchi, Shigeo

2004-03-01

To compare the long-term clinical and experimental results of soft acrylic intraocular lenses(IOLs) manufactured by the lathe-cut(LC) method and by the cast-molding(CM) method. This was a retrospective study of 20 patients(22 eyes) who were examined in a 5- and 7-year follow-up study. Sixteen eyes were implanted with polyacrylic IOLs manufactured by the LC method and 6 eyes were implanted with polyacrylic IOLs manufactured by the CM method. Postoperative measurements included best corrected visual acuity, contrast sensitivity, biomicroscopic examination, and Scheimpflug slit-lamp images to evaluate surface light scattering. Scanning electron microscopy and three-dimensional surface analysis were conducted. At 7 years, the mean visual acuity was 1.08 +/- 0.24 (mean +/- standard deviation) in the LC group and 1.22 +/- 0.27 in the CM group. Surface light-seatter was 12.0 +/- 4.0 computer compatible tapes(CCT) in the LC group and 37.4 +/- 5.4 CCT in the CM group. Mean surface roughness was 0.70 +/- 0.07 nm in the LC group and 6.16 +/- 0.97 nm in the CM group. Acrylic IOLs manufactured by the LC method are more stable in long-termuse.

Development Program for Natural Aging Aluminum Casting Alloys

Energy Technology Data Exchange (ETDEWEB)

Dr. Geoffrey K. Sigworth

2004-05-14

A number of 7xx aluminum casting alloys are based on the ternary Al-Zn-Mg system. These alloys age naturally to high strength at room temperature. A high temperature solution and aging treatment is not required. Consequently, these alloys have the potential to deliver properties nearly equivalent to conventional A356-T6 (Al-Si-Mg) castings, with a significant cost saving. An energy savings is also possible. In spite of these advantages, the 7xx casting alloys are seldom used, primarily because of their reputation for poor castibility. This paper describes the results obtained in a DOE-funded research study of these alloys, which is part of the DOE-OIT ''Cast Metals Industries of the Future'' Program. Suggestions for possible commercial use are also given.

Search for low Energy solar Axions with CAST

CERN Document Server

Cantatore, Giovanni; Aune, S.; Autiero, D.; Barth, K.; Belov, A.; Beltran, B.; Borghi, S.; Boydag, F.S.; Brauninger, H.; Cantatore, G.; Carmona, J.M.; Cebrian, S.; Cetin, S.A.; Collar, J.I.; Dafni, T.; Davenport, M.; Di Lella, L.; Dogan, O.B.; Eleftheriadis, C.; Elias, N.; Fanourakis, G.; Ferrer-Ribas, E.; Fischer, H.; Franz, J.; Galan, J.; Gazis, E.; Geralis, T.; Giomataris, I.; Gninenko, S.; Gomez, H.; Hasinoff, M.; Heinsius, F.H.; Hikmet, I.; Hoffmann, D.H.H.; Irastorza, I.G.; Jacoby, J.; Jakovcic, K.; Kang, D.; Karageorgopoulou, T.; Karuza, M.; Konigsmann, Kay; Kotthaus, R.; Krcmar, M.; Kousouris, K.; Kuster, M.; Lakic, B.; Lasseur, C.; Liolios, A.; Ljubicic, A.; Lozza, V.; Lutz, G.; Luzon, G.; Miller, D.; Morales, A.; Morales, J.; Niinikoski, T.; Nordt, A.; Ortiz, A.; Papaevangelou, T.; Pivovaroff, M.; Placci, A.; Raiteri, G.; Raffelt, G.; Riege, H.; Rodriguez, A.; Ruz, J.; Savvidis, I.; Semertzidis, Y.; Serpico, P.; Solanki, S.K.; Soufli, R.; Stewart, L.; Tsagri, M.; van Bibber, K.; Villar, J.; Vogel, J.; Walckiers, L.; Zioutas, K.

2008-01-01

We have started the development of a detector system, sensitive to single photons in the eV energy range, to be suitably coupled to one of the CAST magnet ports. This system should open to CAST a window on possible detection of low energy Axion Like Particles emitted by the sun. Preliminary tests have involved a cooled photomultiplier tube coupled to the CAST magnet via a Galileian telescope and a switched 40 m long optical fiber. This system has reached the limit background level of the detector alone in ideal conditions, and two solar tracking runs have been performed with it at CAST. Such a measurement has never been done before with an axion helioscope. We will present results from these runs and briefly discuss future detector developments.

Composition of organic matter in earthworm casts depending on litter quality

Science.gov (United States)

Ellerbrock, R. H.; Gerke, H. H.; Schrader, S.; Leue, M.

2009-04-01

Earthworms contribute to decomposition and stabilization of organic matter (OM) in soil. The digestion during intestinal passage inside worms may lead to a change in the composition of OM. It is largely unknown if and how the type of litter the earthworm is feeding on is affecting the OM composition in the casts. Fourier Transform infrared spectroscopy (FTIR) is used to determine the hydrophobic CH- (A) and the hydrophilic CO- (B) functional groups in OM. The objective was to compare the A/B- ratios of litter samples with that of (i) the corresponding casts of the primary decomposer Lumbricus terrestris and (ii) the water contact angles of ground cast samples and at intact cast surfaces. Litter from 10 different plant species including leaves of birch, beech, oak, spruce, pear, mustard and wheat straw (3 replicates) was offered separately to L. terrestris in microcosms containing a Luvisol soil. The OM composition of litter and that of casts, collected from the soil surface after 4-weeks was analyzed with FTIR (DRIFT technique). The A/B ratio of casts was generally increased as compared to that of the soil. For most litter types, the A/B ratio of cast was relatively similar except for casts from birch (Betula pendula) and pear (Pyrus communis) where the OM show a 3-times higher A/B ratio as compared to wheat (Triticum aestivum) or beech (Fagus sylvatica) casts. The higher A/B ratios seem to be related to the relative higher C/N ratios in the casts from Betula pendula and Pyrus communis feeding experiments. The results indicate that digestion of litter by the worm may change OM composition. The assumption that earthworm casts may enrich hydrophobic OM components could be verified only partly. However particulate and soluble OM fractions in the earthworm casts could have contributed to such differentiation.

Is caste destiny? Occupational diversification among Dalits in rural India

OpenAIRE

Ira Gang; Kunal Sen; Myeong-Su Yun

2012-01-01

The caste system - a system of elaborately stratified social hierarchy - distinguishes India from most other societies. Among the most distinctive factors of the caste system is the close link between castes and occupations, especially in rural India, with Dalits or Scheduled Castes (SC) clustered in occupations that were the least well paid and most degrading in terms of manual labour. Along with the Scheduled Tribes (STs), the SCs have the highest incidence of poverty in India, with poverty...

Diabetic Eye Disease

Science.gov (United States)

... Disease, & Other Dental Problems Diabetes & Sexual & Urologic Problems Diabetic Eye Disease What is diabetic eye disease? Diabetic eye disease is a group ... eye diseases that can threaten your sight are Diabetic retinopathy The retina is the inner lining at ...

"Split Cast Mounting: Review and New Technique".

Science.gov (United States)

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

2014-12-01

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

The selective disruption of spatial working memory by eye movements.

Science.gov (United States)

Postle, Bradley R; Idzikowski, Christopher; Sala, Sergio Della; Logie, Robert H; Baddeley, Alan D

2006-01-01

In the late 1970s/early 1980s, Baddeley and colleagues conducted a series of experiments investigating the role of eye movements in visual working memory. Although only described briefly in a book, these studies have influenced a remarkable number of empirical and theoretical developments in fields ranging from experimental psychology to human neuropsychology to nonhuman primate electrophysiology. This paper presents, in full detail, three critical studies from this series, together with a recently performed study that includes a level of eye movement measurement and control that was not available for the older studies. Together, the results demonstrate several facts about the sensitivity of visuospatial working memory to eye movements. First, it is eye movement control, not movement per se, that produces the disruptive effects. Second, these effects are limited to working memory for locations and do not generalize to visual working memory for shapes. Third, they can be isolated to the storage/maintenance components of working memory (e.g., to the delay period of the delayed-recognition task). These facts have important implications for models of visual working memory.

PLC and SCADA based automation of injection casting process for casting of uranium-zirconium blanket fuel slugs for metallic fuel fabrication

International Nuclear Information System (INIS)

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

2016-01-01

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

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

Science.gov (United States)

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...

Grindability of cast Ti-Cu alloys.

Science.gov (United States)

Kikuchi, Masafumi; Takada, Yukyo; Kiyosue, Seigo; Yoda, Masanobu; Woldu, Margaret; Cai, Zhuo; Okuno, Osamu; Okabe, Toru

2003-07-01

The purpose of the present study was to evaluate the grindability of a series of cast Ti-Cu alloys in order to develop a titanium alloy with better grindability than commercially pure titanium (CP Ti), which is considered to be one of the most difficult metals to machine. Experimental Ti-Cu alloys (0.5, 1.0, 2.0, 5.0, and 10.0 mass% Cu) were made in an argon-arc melting furnace. Each alloy was cast into a magnesia mold using a centrifugal casting machine. Cast alloy slabs (3.5 mm x 8.5 mm x 30.5 mm), from which the hardened surface layer (250 microm) was removed, were ground using a SiC abrasive wheel on an electric handpiece at four circumferential speeds (500, 750, 1000, or 1250 m/min) at 0.98 N (100 gf). Grindability was evaluated by measuring the amount of metal volume removed after grinding for 1min. Data were compared to those for CP Ti and Ti-6Al-4V. For all speeds, Ti-10% Cu alloy exhibited the highest grindability. For the Ti-Cu alloys with a Cu content of 2% or less, the highest grindability corresponded to an intermediate speed. It was observed that the grindability increased with an increase in the Cu concentration compared to CP Ti, particularly for the 5 or 10% Cu alloys at a circumferential speed of 1000 m/min or above. By alloying with copper, the cast titanium exhibited better grindability at high speed. The continuous precipitation of Ti(2)Cu among the alpha-matrix grains made this material less ductile and facilitated more effective grinding because small broken segments more readily formed.

Tensile-property characterization of thermally aged cast stainless steels

International Nuclear Information System (INIS)

Michaud, W.F.; Toben, P.T.; Soppet, W.K.; Chopra, O.K.

1994-02-01

The effect of thermal aging on tensile properties of cast stainless steels during service in light water reactors has been evaluated. Tensile data for several experimental and commercial heats of cast stainless steels are presented. Thermal aging increases the tensile strength of these steels. The high-C Mo-bearing CF-8M steels are more susceptible to thermal aging than the Mo-free CF-3 or CF-8 steels. A procedure and correlations are presented for predicting the change in tensile flow and yield stresses and engineering stress-vs.-strain curve of cast stainless steel as a function of time and temperature of service. The tensile properties of aged cast stainless steel are estimated from known material information, i.e., chemical composition and the initial tensile strength of the steel. The correlations described in this report may be used for assessing thermal embrittlement of cast stainless steel components

Stochastic simulation of grain growth during continuous casting

International Nuclear Information System (INIS)

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

2006-01-01

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

Stochastic simulation of grain growth during continuous casting

Energy Technology Data Exchange (ETDEWEB)

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

2006-04-15

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

Strategy of Cooling Parameters Selection in the Continuous Casting of Steel

Directory of Open Access Journals (Sweden)

Falkus J.

2016-03-01

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

Volume Ray Casting with Peak Finding and Differential Sampling

KAUST Repository

Knoll, A.

2009-11-01

Direct volume rendering and isosurfacing are ubiquitous rendering techniques in scientific visualization, commonly employed in imaging 3D data from simulation and scan sources. Conventionally, these methods have been treated as separate modalities, necessitating different sampling strategies and rendering algorithms. In reality, an isosurface is a special case of a transfer function, namely a Dirac impulse at a given isovalue. However, artifact-free rendering of discrete isosurfaces in a volume rendering framework is an elusive goal, requiring either infinite sampling or smoothing of the transfer function. While preintegration approaches solve the most obvious deficiencies in handling sharp transfer functions, artifacts can still result, limiting classification. In this paper, we introduce a method for rendering such features by explicitly solving for isovalues within the volume rendering integral. In addition, we present a sampling strategy inspired by ray differentials that automatically matches the frequency of the image plane, resulting in fewer artifacts near the eye and better overall performance. These techniques exhibit clear advantages over standard uniform ray casting with and without preintegration, and allow for high-quality interactive volume rendering with sharp C0 transfer functions. © 2009 IEEE.

Investigation of Shrinkage Defect in Castings by Quantitative Ishikawa Diagram

Directory of Open Access Journals (Sweden)

Chokkalingam B.

2017-03-01

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

The use of porcine corrosion casts for teaching human anatomy.

Science.gov (United States)

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.

What Is Dry Eye?

Science.gov (United States)

... Eye? Dry Eye Symptoms Causes of Dry Eye Dry Eye Treatment What Is Dry Eye? Leer en Español: ¿Qué ... Inside of Your Eyelid Nov 29, 2017 New Dry Eye Treatment is a Tear-Jerker Jul 21, 2017 Three ...

What Is Dry Eye?

Medline Plus

Full Text Available ... Eye Health A-Z Symptoms Glasses & Contacts Tips & Prevention News Ask an Ophthalmologist Patient Stories Español Eye ... Eye Symptoms Causes of Dry Eye Dry Eye Treatment What Is Dry Eye? Leer en Español: ¿Qué ...

Plans and Measures for Avoiding Casting-Air-Pollution

Institute of Scientific and Technical Information of China (English)

ZHOU Jian

2003-01-01

This article presents plans of preventing casting-air-pollution in practice, and some avoiding methods in detail. In modern times, environment protection is looked high upon day by day; green-casting thus becomes more and more important.

Correlation function measurement of uranium casting driven by tagged DT neutrons

International Nuclear Information System (INIS)

Li Jiansheng; Ye Cenming; Xie Wenxiong; Huang Po; Zeng Liheng; Jin Yu; Xie Qilin; Zhang Yi

2013-01-01

Background: In the nuclear disarmament process, the measurement and verification of uranium casting in sealed container are important to process control and treaty implementation. It is a difficult and hot problem to verify uranium casting in a sealed metal container, due to the weak intensity of neutron and gamma rays of uranium. Purpose: We want to measure the correlation functions of different casting in uranium casting verifications. Methods: Two BC501 scintillation detectors are placed outside the tagged neutron cone and in opposite position. The α detector forms the first channel pulse signal, while the two BC501 scintillation detectors form the second and third channel pulse signals. Those three pulsed time series are recorded by high speed acquisition system. The correlation functions between these signals are calculated by the time series. Results: Putting the two BC501 detectors into the tagged neutron cone, the time of flight for the 14 MeV neutron is measured. The FWHM in TOF spectrum is 2.0 ns. Putting the two BC501 detectors outside the tagged neutron cone, the correlation functions measured by high speed acquisition system and MCA are consistent. The spontaneous neutron decay constants of the castings are measured by γ rays. The decay constant of 6.5 kg Pb component is 184 μs -1 . The decay constants of 4 kg and 15 kg HEU casting are 210 μs -1 and 128 μs -1 , respectively. The correlation functions C 12 (τ), C 13 (τ) and C 23 (τ) are acquired. In C 12 (C), the γ ray peak coming from the inelastic reaction of 14-MeV neutrons with the casting is 5.0 ns before the neutron peak of fission chain. This time difference can estimate the casting position in container. The integrations of the C 12 (τ), C 13 (τ) and C 23 (τ) increase with the casting mass. The C 23 (τ) values of Pb component and DU casting are far less than the values of HEU casting. The C 23 (τ) integration of Pb component is 3.0% comparing with 15-kg HEU casting, while the

Castability of Ti-6Al-7Nb alloy for dental casting

OpenAIRE

Wang, Tie Jun; 小林, 郁夫; 土居, 壽; 米山, 隆之

1999-01-01

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

What Is Dry Eye?

Medline Plus

Full Text Available ... Eye? Dry Eye Symptoms Causes of Dry Eye Dry Eye Treatment What Is Dry Eye? Leer en Español: ¿Qué ... Inside of Your Eyelid Nov 29, 2017 New Dry Eye Treatment is a Tear-Jerker Jul 21, 2017 Three ...

Your Eyes

Science.gov (United States)

... away? If you guessed the eye, you're right! Your eyes are at work from the moment you wake up to the ... the eye is seeing. A Muscle Makes It Work The lens is suspended in ... of the lens. That's right — the lens actually changes shape right inside your ...